Sustainable wastewater treatment: developing a ...

TDO Technologie voor Duurzame Ontwikkeling tien jaar TDO, zesentwintig promovendi en twee postdoc's

Hora Est

Inhoud 5 9 15 20 22 24 26 28 31 36 38 40

Voorwoord Inleiding Biomassa

43 48 51 52 54 57 62 66 70 73 77 80 82 85 89 92

Intelligente netten

- Gas-side fouling in heat-recovery boilers - Growth rates of fouling layers in biomass gasifiers - Analysis of tar removal in a partial oxidation burner - Drop pinch-off from hydrophobic heat exchanger plates - Pyrolysis of wood powder and gasification of wood-derived char

Duurzaam - Driving rain on building envelopes - Radon transport in Autoclaved Aerated Concrete - Physical and sustainable/technical optimization of the IFD today-apartment building system - Pulsed corona-induced degradation of organic materials in water - Energy-Efficient Controlled Induction Motor Drives for Fuel Cell Power Systems - Corona Plasma for Tar removal - Energy-Efficient Controlled Induction Motor Drives for Fuel Cell Power Systems

Schone produktie - Electrocatalytic Reactions of Inorganic Nitrogen-containing Compounds - Catalytic Oxidation of Ammonia to Nitrogen - On the formation and reactivity of multinuclear silsesquioxane metal complexes - Positron Emission Profiling Study of Ammonia Oxidation on Platinum - Composites based on natural fibres and thermoplastic matrices - Scale-up of the Juliá-Colonna epoxidation - Rare earth activated – (oxy) nitride materials

Transities - Modelling and Control of Product Life-Cycles - Sustainable wastewater treatment: developing a methodology and selecting promising systems

97 102

Zonnecellen

105 108

- Growth Related Material Properties of Hydrogenated Amorphous Silicon

110 114

- The Rate-Limiting Factor of the Solid Oxide Fuel Cell

118

Overzicht onderzoeken

- Integration of Expanding Thermal Plasma deposited hydrogenated amorphous silicon in solar cells - Deposition and characterisation of doped (p-type and n-type) ZnO for solar cell and LED applications - Atomic and Molecular Excitation Processes in Microwave Induced Plasmas A Spectroscopic Study

Voorwoord

Prof.dr. Cees Midden Faculteit Technologie Management

In 1992 werd aan de Technische Universiteit Eindhoven begonnen met voorbereidingen voor de oprichting van de gemeenschappelijke commissie van Technologie voor Duurzame Ontwikkeling (TDO). Voor de oprichters was het essentieel dat de gekozen structuur voor TDO zowel een multidisciplinair karakter als een hoge kwaliteit zou kunnen waarborgen. We wilden de TU/e niet opzadelen met een slecht geaccepteerd ‘milieu-eiland’, maar een orgaan creëren dat onderzoekers bij elkaar zou brengen, dat onderwijs over opleidingen kon coördineren en dat ook een belangrijke externe functie zou moeten vervullen als aanspreekpunt binnen de TU/e en als coördinatiepunt voor gemeenschappelijke externe projectwerving met een multidisciplinair karakter. TDO is daarom heel bewust ingericht als een interfacultair orgaan, om het duurzaamheidsonderzoek bij elkaar te brengen. Multidisciplinair onderzoek vraagt altijd extra investeringen, kost extra inspanning en is daardoor moeilijker. Het was dus noodzakelijk om dit extra te stimuleren. TDO heeft dit sinds 1994 bewerkstelligd door middel van de TU/e stimuleringsregeling, waarmee het College van Bestuur via een matching model AIO’s en postdoc’s voor de helft financierde. Om de kwaliteit van het onderzoek te vergroten werd al het TDO-onderzoek ingebed in het onderzoek dat reeds in de verschillende faculteiten en onderzoekscholen plaatsvond. Tevens werd daarmee ongewenste concurrentie tussen TDO en facultaire projecten vermeden. TDO heeft met dit beleid jarenlang succesvol geopereerd. Deze TDO-structuur vond ook navolging, bijvoorbeeld in Delft.

5

Technologie voor Duurzame Ontwikkeling

Preface

demands more investments and extra effort, and therefore is harder to arrange. As a

Prof.dr. C.H.J. Midden, Faculteit Technologie Management

result, this research required an extra boost. TDO realized this by means of an incentive:

Preparations for the foundation of the cooperative committee of technology for a sustai-

the Executive Board partly-financed PhD students and post-docs via a matching model.

nable development (TDO) started in 1992. For the founders, it was essential that the structure for TDO would guarantee a multidisciplinary nature and high quality. We did

To increase the quality of the research, all TDO research was embedded in existing

not want to burden the TU/e with some poorly accepted ‘environmentalist island’,

research in the various departments and research institutes. Undesirable competition

we wanted to create an institute that brings researchers together, coordinates education

between TDO and the projects at the department was avoided. TDO has operated

between departments and would fulfill an important function as a contact point within

for years using this policy. This structure of TDO has even been imitated in Delft for

the TU/e and a coordinative center to obtain joint external projects of a multidisciplinary

example.

nature.

The support of the Excutive Board and TDO at the beginning of projects has led to new

That is why we chose to arrange TDO as an institute between the departments, mainly

research areas and also to more permanent ties between scientists at the TU/e.

to bring the sustainable research projects together. In essence multidisciplinary research

An expressive example of these ties is the biomass working group. In addition, the new Master’s track Sustainable Energy Technology (SET) is set to further enhance relations. In education in general and courses in particular the theme of sustainability was intro-

De hulp van het College van Bestuur en TDO bij de opstart van projecten heeft geleid tot nieuwe onderzoekslijnen en ook meer permanente structuren tussen onderzoekers op de TU/e. Een goed voorbeeld van dat laatste is de biomassawerkgroep. Wellicht dat ook door de nieuwe mastersopleiding Sustainable Energy Technology (SET) de dwarsverbanden extra gesterkt worden.

duced: TDO courses were taught and projects were developed that were integrated into the education programs of several departments. Each student, regardless of the department, was able to obtain a so-called TDO certificate if desired. Unfortunately, the room for further TDO incentives is decreasing. It would be dangerous to conclude that the support given was sufficient, because that is not true. Research in between departments and disciplines requires continuous impulses. The best idea

Ook in het onderwijs werd duurzaamheid verweven: er werden ‘TDO vakken‘ en projecten ontwikkeld die in de verschillende opleidingprogramma’s ingepast werden. Iedere student, ongeacht de studierichting, kreeg de mogelijkheid om een TDO-certificaat te behalen.

would be to continue the support, within the financial room we have. An example might be, less TDO-financed PhD students but more help to obtain external projects. From my own experience I know that these joint projects can be very successful and also fun to participate in.

Het is jammer dat de mogelijkheid om te stimuleren nu afneemt. Je kunt niet zeggen dat er nu genoeg gestimuleerd is, want dat is niet zo. Interfacultair en multidisciplinair onderzoek hebben voortdurend enige stimulans nodig. Het zou dus goed zijn, als de middelen het enigszins toelaten om na te denken over de beste vorm om die te geven. Je zou bijvoorbeeld kunnen denken aan minder eigen AIO’s, maar meer helpen met de werving van externe projecten. Uit eigen ervaring kan ik bevestigen dat zulke gezamenlijke projecten heel succesvol en ook heel leuk kunnen zijn.

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Voorwoord

7


Inleiding

Prof.dr.ir. Rini van Dongen Voorzitter van de gemeenschappelijke commissie

Sinds 7 september 1999 is Prof.dr.ir. Rini van Dongen voorzitter van de gemeenschappelijke commissie van Technologie voor Duurzame Ontwikkeling (TDO). Van Dongen trof, toen hij begon bij TDO, een goedlopende organisatie aan, onder de bezielende leiding van dr.ir. Lex Lemmens als hoofd van het bureau TDO en secretaris van de gemeenschappelijke commissie. Lex Lemmens en ook Cees Midden, de eerste voorzitter, zijn in zijn ogen de grote verwekkers geweest. De invloed van de TDO organisatie zelf speelt een grote rol: het bureau heeft volgens Van Dongen een uiterst stimulerende werking. Het enthousiasme van de medewerkers van bureau TDO en ook met name de activiteiten over de grenzen van faculteiten heen, zijn erg vruchtbaar gebleken. De prachtige brochures over het onderzoek, gemaakt door Ria Overwater (Office Manager) en haar mensen, en natuurlijk niet te vergeten de kalender, zijn daarvan voorbeelden. Ook de fraaie eendaagse seminars over duurzame onderwerpen waren een succes. Daarnaast natuurlijk het onderwijs waar het bureau hard aan heeft gewerkt en nog altijd aan werkt. In de achterliggende periode heeft de Universiteit duurzaam onderzoek sterk gestimuleerd. Stimulering is per definitie tijdelijk. Je geeft voor een beperkte tijd een stimuleringsimpuls, waarna vervolgens een andere structurele manier van financiering gezocht moet worden. Ook TDO is niet ontsnapt aan bezuiniging. Daarbij stond het college van bestuur overigens erg positief tegenover TDO. Er is altijd meegedacht over alternatieven. Het verdient volgens Van Dongen overigens de nadruk dat duurzaamheid gestimuleerd

9


Introduction Prof.dr.ir. M.E.H. van Dongen, Chair of the joint Committee From the 7th of September 1999 on, Prof.dr.ir. Rini van Dongen has been chair of the joint committee of sustainable development (technologie voor duurzame ontwikkeling (TDO)). Upon becoming the chair, Van Dongen found a well-organized institute with an inspiring manager: dr.ir. Lex Lemmens. He is the head of the TDO bureau and also secretary of the joint committee. Lex Lemmens and Cees Midden too, the first chair, are the important ‘fathers’ of TDO according to Van Dongen. The influence of the TDO institute itself is of great importance: Van Dongen thinks the bureau is extremely stimulating. The enthusiasm of the members of the TDO bureau and also the activities across the borders of the departments is very productive. Take, for

door TDO altijd plaats heeft gevonden in het kader van vernieuwend onderzoek van hoog wetenschappelijk niveau. De kwaliteit van het onderzoek is daarbij altijd een erg belangrijke factor geweest. Het duurzame onderzoek vindt nu ook zijn weg naar het onderwijs in de nieuwe MSc-opleiding 'Sustainable Energy Technology' (SET). Het initiatief voor deze opleiding is een gevolg geweest van voorbeeldig samendenken van het college van bestuur, TDO en vertegenwoordigers van de faculteiten, in eerste instantie: Anton van Steenhoven (W), Jaap Schouten (ST), Richard van de Sanden (N), Cees Midden (TM) en Geert Verbong (TM), Jan Blom (E) en Paul Rutten (B). De nieuwe Master-opleiding is volgens Van Dongen een verstandig initiatief met grote toekomst en het geeft bovendien aan TDO een permanente structuur. Het verbindt ook, door het bovenfacultaire karakter, activiteiten van verschillende faculteiten en dat kan volgens Van Dongen niet genoeg gestimuleerd worden. Het is natuurlijk wel zo dat 'technologie voor duurzame ontwikkeling' slechts voor een deel samenvalt met duurzame energie. Het is dus van belang dat ook op de overige gebieden activiteiten blijven bestaan en dat samenwerking wordt bevorderd: bijvoorbeeld op de gebieden afval, grondstoffen, bouw, materialen en milieu. Het is te hopen dat de stimulering ook op deze gebieden voldoende kiemvorming heeft bevorderd. In de toekomst zal het belangrijk zijn om op het niveau van de universiteit hier aandacht voor te houden. Van Dongen ziet dit positief in, er is nu veel aandacht voor SET nodig vanwege het opstarten, maar als dit eenmaal loopt kan de aandacht ook weer gericht worden op andere facetten.

10

Inleiding

Het voortbestaan van TDO in de huidige vorm is in elk geval gegarandeerd zolang er TDO-AIO’s zijn. Over wat er daarna gebeurt zal nog gedacht moeten worden. De bijeenkomsten van de gemeenschappelijke commissie zijn erg vruchtbaar gebleken: het is in de ogen van Van Dongen een club van enthousiaste mensen die het belang inzien van interfacultaire samenwerking. Het biomassalaboratorium is daarvan een mooi voorbeeld. Er zijn tal van initiatieven, contacten, organisaties ontstaan als gevolg van het bestaan van de TDO-organisatie. Kortom, al met al is de algemene indruk van Van Dongen over het stimulerende optreden van TDO erg positief.

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example, the exquisite brochures about the research projects, created by Ria Overwater

future. Moreover, it helps to create a permanent structure for the activities of TDO.

(Office Manager TDO) and her co-workers, and of course the calendar. Moreover, the splendid one-day seminars about sustainable topics were a success. And apart from all

In addition, its multidisciplinary nature connects activities in several departments.

this, there were the courses that the bureau was working on as well.

Van Dongen feels that these activities cannot be stimulated enough. However, 'Technology for sustainable development' only partly coincides with

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In the past few years, the university strongly stimulated sustainable research. Part of the

sustainable energy. So it is important that in the remainder of the research areas

problem with stimulation is that it is by definition of a temporary nature. For a certain

activities are continued and that the cooperation is stimulated in those areas as well:

time incentives were applied, but after that a structural solution for financial support has

for example in the areas waste, building and architecture, materials and environment.

to be found. Moreover, TDO did not escape from the spending cuts. The Executive Board

Let us hope that the TDO incentive has already created enough nuclei. In the future, it

was very positive about TDO, however, and they tried to help out and find alternatives.

will be important to monitor these research projects. Van Dongen thinks this is possible:

Van Dongen emphasizes that the sustainability supported by TDO was innovative and

right now the new Master’s track SET requires a lot of attention because of the start-up,

of a high scientific level. The quality of the researches has been a very important factor.

but once it has started we will focus our attention on other areas.

The sustainability research has also resulted in sustainability education at the TU/e in

The continued existence of TDO in the present configuration is guaranteed as long as

the new Master’s track 'Sustainable Energy Technology' (SET). The initiative for this

there are TDO-PhD students. Some thinking is required about what has to happen

track is a result of the cooperation of the Executive Board, TDO and representatives

afterwards. The meetings of the joint committee are very productive: according to

from the departments: Anton van Steenhoven (Mechanical Engineering), Jaap Schouten

Van Dongen this committee is a group of enthusiastic people who are aware of the

(Chemical Technology), Richard van de Sanden (Applied Physics), Cees Midden

importance of multidisciplinary cooperation. The biomass laboratory is a perfect

(Technology Management) and Geert Verbong (Technology Management), Jan Blom

example of this. Numerous initiatives, contacts, and organizations were started as a

(Electrical Engineering) and Paul Rutten (Building and Architecture). According to Van

result of the TDO institute. In short, taken as a whole, the general impression of Van

Dongen, the new Master’s track is a sizeable initiative with large implications for the

Dongen about the stimulating performance of TDO is very positive.

Inleiding

13


Biomassa Prof.dr.ir. Anton van Steenhoven Faculteit Werktuigbouwkunde

De stimulering van Technologie voor Duurzame Ontwikkeling (TDO) van het onderzoek bij de sectie energie technologie van Prof.dr.ir. Anton van Steenhoven is gericht op twee verschillende gebieden: enerzijds de vervuiling van warmtewisselaars, anderzijds de gasreiniging bij biomassavergassing. Op het gebied van de vervuiling zijn twee AIO’s gefinancierd door de stimuleringsregeling van TDO. De eerste AIO was Dr.ir. Marco van Beek. Het vervolg op dit project wordt gedaan door Mohammed Abd Elhady MSc. Hij is momenteel nog bezig met zijn onderzoek. Bij de toepassing van warmtewisselaars om afvalwarmte terug te winnen vormt vervuiling een belangrijke beperking. Door vervuiling neemt het rendement van de warmtewisselaar af. In het ergste geval kan vervuiling leiden tot het uit bedrijf nemen van de installatie. In het onderzoek van Van Beek is de vervuiling zoals deze optreedt in de ketel van een afvalverbrandingsinstallatie (AVI) als voorbeeld genomen. Vervuiling wordt hier veroorzaakt door het neerslaan van vliegasdeeltjes op een pijpenbundel in de ketel in combinatie met condensatie en chemische reacties. Om de aangroeisnelheid van een vervuilingslaag te minimaliseren is een model ontwikkeld waarmee als functie van de geometrie van een pijpenbundel en de procescondities, de lokale aangroei voorspeld kan worden. De vervuilingssnelheid wordt berekend met een computermodel dat het transport van deeltjes door de warmtewisselaar beschrijft in combinatie met een analytisch model voor het plakgedrag van deeltjes die op een pijpenbundel botsen. Dit laatste model is geverifieerd met experimenten waarin de botsing van deeltjes met poederachtige lagen is geanalyseerd.

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Biomass

cooperation that is formed between the Department of Mechanical Engineering (Energy

Prof.dr.ir. A.A. van Steenhoven, Department of Mechanical Engineering

Technology Group) and the Department of Chemical Engineering. The fouling research

The TU/e incentive arrangement for sustainable development (technologie voor duurzame

includes both heat and mass transport, as well as chemical reactions. In this way a link

ontwikkeling (TDO)) of the research in the energy technology group of Prof.dr.ir. Anton

between the two departments could be established. The collaboration with the group of

van Steenhoven focuses on two separate areas. One research area is the fouling of heat

Prof.dr.ir. Keurentjes in particular is very productive: three new PhD projects are being

exchangers. The other area is the gas cleaning of gases from biomass gasification. For

formed. These projects will all be financed without the help of TDO. Even a new (but

the fouling research two PhD students are being supported by TDO. The first PhD

related) research subject is being introduced: chemical fouling. The PhD study about

student was Dr.ir. Marco van Beek. The project is now being continued by Mohammed

chemical fouling is being done by Dr.ir. Misheck Mwaba MSc. It too has had no support

Abd Elhady MSc. This project is not finished yet. In the area of biomass gasification,

from TDO.

Dr.ir. Marja Houben studied the removal of tar from biomass gasification gases.

In the area of biomass research there was interaction with the Department of Chemical Engineering too. The combustion group of Prof.dr. Philip de Goey is closely involved in

Van Steenhoven thinks that the most profitable effect of the incentive is the structural

Uit berekeningen is gebleken dat door aanpassing van de geometrie van de pijpenbundel de aangroeisnelheid van vervuilingslagen verminderd kan worden. In het vervolgonderzoek van Abd Elhady ligt het accent op de verwijderingsaspecten, waardoor de vervuilingslaagdikte een asymptotische groei vertoont, en wordt ook de link naar biomassavergassers gelegd Belangrijk is te vermelden dat dit vervuilingsonderzoek fundamenteel van aard is: het gaat om het volgen van individuele deeltjes en om de interactie met wanden. Dit heeft geleid tot geavanceerde deeltjes-interactie-modellen en het beschouwen van deeltjesdynamica. Deze nieuwe wetenschapsgebieden, ook wel granulaire stromingen genoemd, kunnen na de TDOstimulering tijdens het opstarten van het onderzoek, nu verder uitgroeien met externe financiering. Want ook de maatschappelijke relevantie blijkt groot, je zou bijvoorbeeld kunnen denken aan de vervuiling in de Amercentrale. Naast de onderzoekslijn over vervuiling is een lijn opgezet over biomassavergassing. Dr.ir. Marja Houben heeft gewerkt aan het verwijderen van teren bij vergassing van biomassa. Biomassavergassing is een veelbelovende optie voor duurzame energieproduktie. Bij het introduceren van vergassers die geschikt zijn voor kleine schaal, vormt de teer die ontstaat tijdens het vergassingsproces een bron van zorg. Behalve dat het slecht is voor het milieu en de gezondheid, veroorzaken teren ook problemen in de nageschakelde processen, vooral doordat ze condenseren. Voordat het gas in een gasmotor gebruikt kan worden, moet het teergehalte in het gas daarom

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Biomassa

the projects as well. The project will be continued and financed by NOVEM.

verlaagd worden tot acceptabele waarden. Een veelbelovend concept voor kleinschalige applicaties verwijdert de teren door het verbranden van een deel van de gassen. Dit partiële verbranden zal de teren verwijderen: deels door de thermische behandeling en deels door de partiële oxidatie. Van Steenhoven vindt het aardige van de TDO stimulering dat het een structurele samenwerking van de faculteit Werktuigbouwkunde (energie technologie) met de faculteit Scheikundige Technologie op gang gebracht heeft. Het onderzoek naar de vervuiling omvat zowel warmte- en massatransport en chemische reacties, en legt daarmee een brug tussen beide disciplines. Met name samenwerking met de groep van Prof.dr.ir. Keurentjes op dit gebied is erg vruchtbaar: er zijn drie promotieonderzoeken uit voort gekomen en de onderzoekslijn kan nu op eigen kracht, dus zonder TDO stimulering, via externe financiering worden voortgezet. Ook is een nieuwe zijlijn ingeslagen met betrekking tot de chemische vervuiling in een project dat gedaan is door Dr. Misheck Mwaba MSc, ook los van de TDO stimulering. Ook op het gebied van de biomassavergassing is interactie met de faculteit scheikunde ontstaan. Na het project dat gestimuleerd werd door TDO, wordt het vervolgproject gefinancierd door NOVEM (Nederlandse Organisatie voor Energie en Milieu). Tevens is de verbrandingsgroep (bij de faculteit werktuigbouwkunde) van Prof.dr. Philip de Goey nauw betrokken bij het onderzoek. Een ander sprekend voorbeeld van de samenwerking, is het biomassalaboratorium. Dit is het resultaat van de spin-off van de TDO stimulering. Intussen is al heel wat apparatuur bij elkaar gebracht in dit laboratorium,

17


Another clear example of cooperation is the biomass laboratory. This is a result of

created a basis for follow-up research now financed with secondary or tertiary support.

the spin-off of the TDO incentive. A lot of equipment is gathered in this lab. Set-ups

The sustainable energy research also is a basis for the courses that will be taught in the

from the Chemical Engineering department, the Department of Applied Physics, the

new Master’s program Sustainable Energy Technology (SET).

Mechanical Engineering department and in the future maybe the Electrical Engineering department are or will be placed in the lab. This facility gives Master’s students and trainees the opportunity to do their research here. Projects concerning biomass are already being carried out in this laboratory. The part-time professors Prof.ir. Kees Daey Ouwens (energy from biomass) and Prof.dr.ir. Ronald Van Zolingen (solar energy) significantly contributed to the realization of sustainable research within the Energy Technology group. Without the TDO incentives, the research would not have been as fundamental as it is. The support

waar opstellingen van scheikundige technologie, natuurkunde, werktuigbouwkunde en in de toekomst bijvoorbeeld ook elektrotechniek een plek vinden. Daarnaast bieden de faciliteiten gelegenheid voor opstellingen voor afstudeerders van deze opleidingen. In het biomassalaboratorium vinden nu al projecten plaats in het kader van biomassa. De deeltijdhoogleraren Prof.ir. C. Daey Ouwens (biomassa) en Prof.dr.ir. R. Van Zolingen (zonnecellen) hebben een belangrijke bijdrage geleverd aan het tot stand komen van de duurzame onderzoeken binnen de groep. Zonder de financiering van TDO was het niet mogelijk geweest om het onderzoek zo fundamenteel van aard te laten zijn. Door de financiering is nu een basis gelegd voor vervolgprojecten die dan gefinancierd worden uit de tweede en derde geldstroom. Het lopende duurzame energie-onderzoek heeft ook zijn plek gevonden in het onderwijs via vakken die gegeven worden in het kader van de masteropleiding Sustainable Energy Technology (SET).

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Biomassa

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Gas-side fouling in heat-recovery boilers whether the particle sticks and deposits or rebounds. The sticking model is based on the assumption that the impact of the particle on the layer can be modelled as a two-body collision with the second body representing the layer. The mass of this second body is assumed to be proportional to the mass of the incident particle. Besides the proportionality factor between the two masses, also the coefficient of restitution and the friction coefficient are important model parameters. For the coefficient of restitution, a measure for the amount of energy losses over an impact, a separate model is presented.

Promotors: Prof.dr.ir. A.A. van Steenhoven and Prof.dr.ir. J.T.F. Keurentjes Copromotor: Dr.ir. C.C.M. Rindt Department of Mechanical Engineering, Energy Technology Department of Chemical Engineering, Proces Development

To validate the two-body approach and to determine the model parameters an experimental set-up has been built. In this set-up impact experiments are performed on different surfaces. From an experiment on a solid glass surface the coefficient of restitution and the friction coefficient are measured. Experiments on a powdery layer show that the proportionality factor is 3.5 for a layer composed of particles with the same size as that of the incident particles and 2.6 for a layer consisting of particles of 6.6 times smaller particles. With these proportionality factors, it is found that the agreement between the two-body model and the experiments performed at different impact angles and incident velocities is satisfactory.

Marco van Beek - 2002 - Department of Mechanical Engineering The formation of an insulation layer on the heat transfer surfaces, knows as fouling, is a common problem in heat-recovery applications. The boiler in a refuse waste incinerator is an example of such an application. On the gas-side of the tubes in this boiler a layer develops because of the deposition of fly-ash particles. As observed, the character of the layer formed is related to the local gas and tube temperatures. On the superheater tube bundle the layer is thick and sintered while on the economiser bundle the layer is thin and powdery. The difference in both types of layers resulted in a 27% reduction of the overall heat transfer coefficient. In this investigation a model is developed with which the rate of deposition can be calculated as a function of the process conditions and the geometry of the bundle. The model is confined to the formation of a powdery layer.

Using the developed deposition model calculations have been performed for various tube bundle geometries. In the original economiser geometry, it is found that predicted disposition rates closely resemble the disposition rates as estimated from the observed decrease in the heat transfer for the economisers. Furthermore, it is found that deposition is reduced when the distance between two tube rows in the direction normal to the main stream velocity is decreased, a staggered instead of an in-line arrangement is applied when elliptical instead of circular tubes are used. On the basis of these recommendations, the deposit rates can be reduced with more than 75%, limiting the decrease in heat transfer coefficient due to fouling to 8% compared to the original 27%.

In the developed model the transport of particles from the gas to the tube walls was simulated by individual particle tracks in a computed flow field. The turbulent flow field is calculated using a low-Reynolds k-ε model and for the particle tracking use is made of an eddyinteraction model. This model has been modified to take anisotropy in the boundary layer into account and to compensate for steep gradients in the flow characteristics upstream of the tube. Using the modified model calculated transport rates agreed well with values reported in literature. After a particle has reached the tube wall a sticking model determines

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Biomassa

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Growth rates of fouling layers in biomass gasifiers has a different fouling behavior than powdery layers. The aimed progress is to develop the removal model to take into account the interaction of an incident particle with a sintered fouling layer.

Promotor: Prof.dr.ir. A.A. van Steenhoven Copromotors: Dr.ir. C.C.M. Rindt and Ir. J. Wijers Department of Mechanical Engineering,

Removal of particles from the fouling layer due to shear forces is investigated. Fouling experiments have been done with particles of different sizes and different materials running under different gas speeds at the University of Twente. It is found that the smallest particles in the flow deposit first on the tubes of the heat exchanger at areas of minimum flow velocities. Then the large particles deposit and the fouling layer starts to build up. The fouling layer thickness and growth over the heat exchanger tube is influenced by the flow speed. As the flow speed in the heat exchanger increases, the thickness and the surface area of the fouling layer deposited over the heat exchanger tube are reduced. There is a limiting flow speed above which fouling is avoided. This limiting speed is related to the critical flow velocity required to roll a particle resting on a flat surface. The influence of particle size distribution on the selection of the limiting fouling speed still has to be investigated in more detail.

Energy Technology

Mohammed Abd-Elhady - lopend - Department of Mechnical Engineering Particulate fouling is defined as the deposition of unwanted materials, particles, on a heat exchange surface. Fouling in biomass gasifiers may lead to highly inefficient systems. The objective of the research is to model the growth rate of powdery fouling layers in biomass gasifiers. To model the growth rate of powdery fouling layers using commercial CFD-codes, a deposition model is required. The present deposition models do not take into account removal of particles from powdery fouling layers. Removal may take place as a result of impaction of particles on the fouling layer or as a result of the shear forces exerted by the fluid on the particles embedded in the fouling layer. A numerical removal model is developed to study the interaction of an incident particle with a bed of particles. The numerical model is based on the molecular dynamic theory of granular matter. The numerical model is verified experimentally. An experimental setup has been built to study the removal of particles from powdery fouling layers due to an incident particle impact. The numerical results show a good comparison to the experimental results. The numerical model is used to characterize the removal of particles from powdery fouling layers as a function of particle size, material, incident particle impact speed and angle.

The fouling layers in biomass gasifiers are subjected to high operating gas-side temperature. The high temperature of the gas-side causes sintering of the fouling layer. Sintering causes the fouling layer structure to change from a loose powdery structure to a robust structure, which

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Analysis of tar removal in a partial oxidation burner Promotors: Prof.dr.ir. A.A. Steenhoven and

mixtures in various compositions resembling biogas are used, without using tar. It is possible to operate the burner in a stable way using little air at low caloric values (down to 3 MJ/Nm3). So the burner meets the demands for the burning part of the process. The outlet temperature and gas composition are measured at several heating values, powers, fuel inlet compositions and air factors (λ). For the gas compositions used, it is seen that methane is converted to carbon monoxide and hydrogen. For the part of the process downstream of the burner, normal and stereo particle image velocimetry (PIV) are used to study the flow field. Also temperature measurements are performed. The temperature measurements downstream of the burner show that at a distance of about two times the diameter of the burner, a homogeneous mixture is attained. The stereo PIV measurements point out that the flow is weakly swirling (S ≈ 0.2). A strong decay of the swirling motion is seen at the same height where the temperature becomes homogeneous. The effect of thermal treatment (λ = 0) on the tars is studied using an experimental set-up at the Energy Research Centre of the Netherlands (ECN). A sooting trend is seen in these experiments: smaller carboncontaining ring compounds seem to convert step by step to soot. The longer the residence times the higher the amount converted into soot, and also an acceleration of the sooting process is seen with an increase of the temperature. Finally, the effect of partial oxidation on tar is studied in the burner geometry. Naphthalene is used as a model compound in these experiments. When adding some primary air (λ = 0.2), the total tar concentration is low. Interesting is, that when more air (λ > 0.4) is added to the burner, the same sooting tendency is found as in the case of thermal treatment only. By changing the inlet gas composition by adding more hydrogen, the tar concentration in the outlet is considerably affected. Hydrogen seems to be an inhibitor for soot formation: only a small amount of hydrogen present in the inlet gas transforms the sooting/polymerisation process into cracking. When considering the inlet gas compositions that resemble biogas and a λ of 0.2 as preferred, little tar is found downstream of the burner: only 7.5 % of the inlet mg/Nm3. Therefore, the process created by the burner geometry might be a promising method for the application to small-scale biomass gasifiers.

Prof.dr. L.P.H. de Goey Copromotor: Dr.ir. H.C. de Lange Department of Mechnical Engineering, Energy Technology

Marja Houben - 2004 - Department of Mechnical Engineering Biomass gasification is an interesting option for renewable energy production. However, for the introduction of small-scale gasifiers using biomass, the tar produced in this process is one of the major problems. Apart from causing environmental hazards, tar is known to create process-related problems in the end use devices, such as fouling, corrosion, erosion and abrasion. Before the gas can be introduced into the gas engine, the tar content has to be reduced to low values. A promising concept for small-scale applications, is to remove the tars by burning a small part of the gas. This partial burning will remove the tars; supposingly both by thermal cracking and partial oxidation. To investigate the removal processes, a burner geometry is evaluated and modified.The geometry should meet various demands: low caloric gas (5-12 MJ/Nm3) should be burned in a stable way using little air, creating a homogeneous temperature for the thermal treatment of the burnt and unburnt gas downstream of the burner. In this process the mixing is crucial: on one hand the mixing should not be too turbulent, because locally a stoichiometric mixture should create diffusion flames; on the other hand however, the mixing should be turbulent enough to make the temperature homogeneous downstream of the burner. First, the burner geometry is tested in a perspex (polymethyl metacrylate) set-up using water. By scaling this set-up by the Reynolds number, information was gained about the mixing process in the burner geometry and an optimal value for the ratio of the volume flows is found. The final set-up is built in stainless steel. In this set-up several gas

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Drop pinch-off from hydrophobic heat exchanger plates to find by which mechanism drops break off a heat exchanger plate. Some experiments are performed using ethane at near-critical conditions. Various variables, i.e. temperature, pressure, liquid and vapour density, the shape of the downstream edge, plate orientation, vapour velocity and surface tension coefficient have been varied to observe the effect on drop pinch-off.

Promotors: Prof.dr.ir. J.J.H. Brouwers and Prof.dr. A.A.H. Drinkenburg Copromotor: Dr. C.W.M. van der Geld Department of Mechanical Engineering, Proces technology Department of Chemical engineering,

During pinch-off from a vertical plate at low to moderate Weber numbers, a drop is stretched until the neck breaks. Drop size and the number of satellites formed depend mainly on Bond and Weber numbers, although no correlation has been found describing all measurements.

Process, product and design

Axel Lexmond - 2003 - Department of Mechanical Engineering

During pinch-off from a vertical plate at relatively high Weber number, or pinch off from a horizontal plate, the drop is stretched and oscillates perpendicular to the plate. The amplitude of the oscillation increases, until break-up follows. This breakup mechanism results in relatively small drops after pinch-off.

Compact PVDF heat exchangers are used to recover heat from highly polluted gas streams. Quite often, water vapour condenses in the heat exchanger, forming drops on the cold plates. Pinch-off of these drops from the downstream edge causes condensate to be re-entrained into the gas stream, possibly damaging downstream equipment and reducing thermal efficiency.

The shape of water drops during break-up has been used to calculate various forces that act on a drop pinching off a horizontal plate. The magnitude of the surface tension force and hydrodynamic force are much bigger than the magnitude of gravitational forces acting on the drop. However, plate orientation (or the direction of the gravitational force) has a large influence on the process of drop break-up. Changing a plate from vertical to horizontal has, at one condition, resulted in a decrease in drop volume after pinch-off by a factor 40. This large difference is caused by the difference in break-up mechanism (stretching versus oscillating) between the two situations.

The goal of this study is to increase the knowledge of the causes and consequences of drop pinch-off, as occurring in hydrophobic polymer heat exchangers. To this end, three aspects have been investigated. Firstly, re-entrainment, which is caused by drop pinch-off, has been studied in an small scale heat exchanger to quantify the effect of drop pinch-off on the overall heat and mass transfer rate. For this heat exchanger re-entrainment is found to depend on the total condensate flux and the Weber number of the gas flowing around the drop. A case study is used to quantify the effect of re-entrainment on heat and mass transfer. At typical industrial conditions, a re-entrainment rate of 10% reduces the thermal efficiency of the next heat exchanger in a heat exchanger cascade by 7%. It is also shown that a PVDF heat exchanger can be used to collect hydrogen fluoride from a polluted gas stream, but that 10% re-entrainment reduces the gas cleaning efficiency from 99.3 to 90%.

Thirdly, several experiments have been performed at well-defined conditions, which allow validation of numerical simulations of drop pinch-off in forced convective flow. Drop break-up has been simulated using a diffuse interface model. Comparison between numerical simulation and physical experiment has shown that at this moment, the simulation does not correctly describe drop pinch-off. Reasons for this are thought to be the use of a 2D grid and the large grid size. Most importantly, it shows that the measurements can be used for validation of multiphase flow simulations of changing topology without density matching at relatively high vapour velocities.

Secondly, experiments are performed in two single plate mock-ups

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Pyrolysis of wood powder and gasification of wood-derived char Promotors: Prof.dr.ir. M.E.H. van Dongen and

subsequently exposed to a CO2 environment. The gasification reaction is observed by means of infrared absorption spectroscopy, monitoring the CO-concentration versus time. A restriction of the applied procedure appeared to be the rather long heating-up time of the grid electrodes and of the grid itself. In order to circumvent this problem, char is produced in a separate oven and subsequently deposited on the preheated grid. To acquire an amount of char, sufficient for its characterization as well as for the gasification experiments, a series of chars has been produced at different final pyrolysis temperatures. By means of Scanning Electron Microscopy and the physical adsorption of CO2, the morphology and the pore structure of the chars are characterized. The results show that the produced char has very narrow pores of the order of 0.5 nm. Higher pyrolysis temperature promotes the increment of the micropore volume and of the heterogeneous surface. The gasification of these chars with pure CO2 is tested in a temperature range of 1300 K-1900 K at atmospheric pressure in the grid reactor. From the grid reactor experiments, it is found that the pyrolysis temperature, pressure and hold time have effect on the char gasification rate. In the temperature range of 1300 K-1900 K, no diffusion limitation is found. The activation energies of the chars vary from 100 kJ/mol to 210 kJ/mol, depending on their preparation conditions.

Prof.dr. W.R. Rutgers Copromotor: Dr. A. Veefkind Department of Applied Physics

Jieheng Guo - lopend - Department of Applied Physics In this thesis, fast pyrolysis of wood particles and gasification of woodderived char are investigated. To obtain insight in the kinetics of both processes, and to examine the interaction between the transport phenomena and the chemical reaction. Fast pyrolysis of Lignocel wood is studied in a shock tube reactor. Small wood particles (about 10µm in diameter, 50 µm in length) are suspended in nitrogen, prior to the heating of the particles due to shock compression. This compression results in a fast heating process that enables to follow the chemical conversion process at constant temperature. Temperatures range from 950 K to 1500 K at 0.8 MPa. A light extinction technique is applied for the time resolved characterization of the conversion process and two-wavelength pyrometry is applied to measure the temperature of the particles. An analysis is made of the shock induced particle motion and the heat transfer processes between particles and the surrounding gas. It is shown that the conversion is chemically controlled at temperatures below 1220 K. In this regime, pyrolysis of Lignocel wood particles is well described by a near first order reaction with an activation energy of 106 ± 18.5 kJ/mol and a pre-exponential factor of (9.8 ± 2.3)×108 1/s.

To understand the physics of the gasification process in a complex porous material, a model is developed, which takes into account the interplay between the diffusion of gaseous species and the gasification reaction for the binary case (CO2) and for the ternary case (CO2/N2), respectively. The diffusion of the gaseous species is described by the dusty gas model and the gasification reaction by the Langmuir kinetics. The effects of the temperature, total pressure and pore size on the intra-particle mole fractions of gaseous species, molar flux of CO and the surface reaction rate are primarily studied by means of the model. For both cases, diffusion plays no role in the gasification of the present chars under the operating conditions of interest, namely T < 2000 K, P < 2 bar and rc = 5 µm. This is due to the small particle size. Knudsen diffusion is the dominant diffusion process under the conditions mentioned above. The addition of nitrogen decouples the diffusion processes of CO2 and of CO. Therefore, diffusion is promoted with the addition of nitrogen but the effect is subtle.

Gasification of wood-derived char is the second main theme of this study. The experimental facility used is a closed grid reactor. In such a reactor char particles are heated on a thin-wired platinum grid up to a maximum temperature of 2000K. In the first series of experiments Lignocel wood particles are first pyrolysed in the grid reactor and

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Duurzaam bouwen Prof.ir. Nico Hendriks Faculteit Bouwkunde

In de capaciteitsgroep FAGO, waar Prof.ir. Nico Hendriks toe behoort, zijn drie promovendi gestimuleerd door Technologie voor Duurzame Ontwikkeling (TDO). Twee onderzoeken zijn intussen al afgerond. Het ene onderzoek gaat over de invloed van slagregen op de duurzaamheid van de gebouwschil en het andere over productie en transport van radon in bouwmaterialen. Het derde onderzoek loopt momenteel nog. Dit project, dat gedaan wordt door Ir. Haico van Nunen, gaat over industrieel, flexibel en demontabel bouwen (IFD). Het onderzoek loopt volgens Hendriks voorspoedig. Het proefschrift van Dr.ir. Fabien van Mook gaat over de invloed van slagregen. De duurzaamheid van een gebouwschil (gevels en daken) is beperkt door degradatie zoals vanwege warmte- en vochttransport, depositie van chemische stoffen, ontwerpfouten en fouten tijdens de bouw. Voor een duurzaam ontwerp is kennis van de blootstelling van het gebouw aan atmosferische invloeden een vereiste. Van Mook heeft één van de belangrijke micro-klimatologische parameters onderzocht, namelijk slagregen (in het Engels ‘driving rain’ of ‘wind-driven’ rain genoemd). Het onderzoek had de volgende doelen: 1) het ontwikkelen en testen van slagregenmeters; 2) het gedetailleerd meten van slagregen op de gevel van een gebouw samen met de relevante meteorologische grootheden; 3) het ontwikkelen en toepassen van simulaties en rekenmethodes voor slagregen op de gebouwschil, geverifieerd met metingen in dezelfde situatie.

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Sustainable building

being carried out together with Prof.dr.ir. de Wit, who is also from the FAGO Group

Prof.ir. N.A. Hendriks, Department of Building and Architecture

of the Department of Building and Architecture. One project is completely financed by

In the FAGO group of Prof.ir. Nico Hendriks, three PhD students are being financed via

the university. The other project is partly financed by 'Knowledge Center for Building

the TU/e incentive arrangement for sustainable development (techniek voor duurzame

and Systems' (KCBS) and partly by the university.The KCBS is a cooperative of the TU/e

ontwikkeling (TDO)). Two of the researches have already been finished. One study

and TNO.

was on the influence of driving rain on the long-term use and durability of building envelopes; the other study was on the production and transport of radon in building

A problem encountered by building and architecture is that the building industry is

materials. A third project is still on-going. This project, which is being done by Ir. Haico

not aimed at research. That is why Hendriks so much appreciates the incentives of

van Nunen, addresses Industrially Flexible and Demountable (IFD) building. This re-

sustainable development (TDO): in this way it is possible to do socially relevant research

search is progressing smoothly according to Hendriks.

without obstructions that might emerge from the building industry. According to Hendriks, it is hard to obtain good candidates for the PhD positions for example.

Two PhD students are now continuing the driving rain research area. These studies are

Twee promovendi gaan nu verder met deze onderzoekslijn over slagregen. Deze onderzoeken worden uitgevoerd in samenwerking met Prof.dr.ir. de Wit, eveneens van FAGO van de faculteit Bouwkunde. Een van de twee wordt nog volledig gefinancierd uit de eerste geldstroom. De andere promovendus wordt voor de helft gefinancierd door het KennisCentrum voor Bouwen en Systemen (KCBS) en voor de rest uit de eerste geldstroom. Dit KCBS is een samenwerkingsverband tussen de TU/e en TNO. Een probleem is dat de bouw niet gericht is op onderzoek. Daarom vindt Hendriks de stimulering van TDO zo geweldig: zo was het toch mogelijk om maatschappelijk relevant onderzoek te doen, zonder belemmerd te worden door belangen vanuit de bouwindustrie. Volgens Hendriks is het bijvoorbeeld moeilijk om goede kandidaten te vinden voor de AIO-posities. Dr. Michel van der Pal heeft bijvoorbeeld een chemische achtergrond. Het onderzoek van Van der Pal gaat over productie en transport van radon in bouwmaterialen. Radon, een radioactief edelgas, wordt gezien als één van de grootste bedreigingen van de gezondheid in het Nederlandse binnenmilieu. Naar schatting van de Wereld Gezondheids Raad (WHO) veroorzaakt de radon aanwezig in Nederlandse woningen zo'n 800 gevallen van longkanker per jaar. Hiermee overschrijdt radon de door de overheid gestelde maximale risico voor één enkele bron. Het doel van het promotie-onderzoek is om inzicht te krijgen in de processen die een rol spelen bij de productie en transport van radon in bouwmaterialen. Hiertoe is een opstelling gebouwd waarin de productie en

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Dr. Michel van der Pal is a chemical engineer rather than a building engineer.

transport van radon in bouwmaterialen nauwgezet kan worden gemeten en gestuurd. Door vergelijking van deze metingen met modelberekeningen kunnen de huidige fysische modellen worden getoetst op hun geldigheid. Hendriks wil samen met medepromotor Dr. Rob de Meijer van Natuurkunde, dolgraag een vervolgonderzoek van het project van Van der Pal. Het blijkt alleen enorm moeilijk om aan financiering te komen voor dit soort onderzoek. Ambitieuze voorstellen liggen al bij Hendriks op tafel. Aan geld komen is echter een probleem: bij veel van de bouwkundige onderzoeksonderwerpen zit je namelijk al snel vast aan industriële belangen. In het geval van radon is de betonindustrie er bijvoorbeeld helemaal niet zo blij mee. Het ministerie van Volkshuisvesting en Ruimelijke Ordening (VROM) wil het project wel steunen, maar niet met al te veel geld. De betonindustrie wil ook wel mee doen, maar dan meer om een oogje in het zeil te kunnen houden. Daarnaast worden er geen eerste geldstroom projecten meer gefinancierd. Door al deze factoren is het moeilijk financiering voor deze tweede onderzoekslijn te krijgen. Daarom was het onafhankelijk onderzoek voor TDO ideaal voor de onderzoekers. Hendriks is heel positief over TDO, in zijn ogen is de stimulering zeer succesvol geweest. Hendriks neemt met zijn groep geen deel in de mastertrack Sustainable Energy Technology (SET). Het onderzoek aan energiebesparing in de bouw is volgens Hendriks namelijk in de basis al klaar. Dat wil niet zeggen dat het niet belangrijk is, maar het afvalprobleem in de bouw ziet hij als een veel groter probleem. Soms wordt wel 10% van het geleverde materiaal

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Hendriks, together with PhD supervisor Dr. Rob de Meijer of the Department of Applied

Hendriks and his group, do not participate in the Master’s track Sustainable Energy

Physics, would like to continue the research done by Van der Pal. However, it has

Technology (SET). Research on energy saving in the built environment is finished

proved to be very hard to acquire financial support for this type of research. Ambitious

according to Hendriks. This does not mean that it is not important, but the research

proposals are lying ready on Hendriks’ desk. Unfortunately, money is a problem: many

concerning building waste is a larger problem. Sometimes 10% of the delivered material

of the research areas are tied to industrial interests. In the case of radon, the concrete

is discarded again as waste material. So from a research viewpoint, the waste problem

industry is a hesitant partner. The public housing department (VROM) wants to support

more interesting than the energy problem.

the project, but they do not want to spend too much money. The concrete industry would

Hendriks regrets that the support of TDO is coming to an end. He is now chair of one

like to support a little research to keep an eye on matters. The university stopped all

of the sustainable chemical development (DCO) platforms. These platforms want to

funding. So, all these factors make it really hard to find money for the second research

bring different institutes together: university, industry and knowledge institutes. The

area: the radon. That was why the independent research for TDO was an ideal situation

platforms will mainly be concerned with the research areas of renewable materials and

for the researchers. Hendriks feels very positive about TDO, he feels that the support by

functional polymers. Hendriks will be able to extend part of the research that was started

TDO has been very successful.

using the TDO incentives.

als afval weer weggegooid. Wat betreft onderzoek is dit afvalprobleem dus interessanter dan het hele energieverhaal. Hendriks vindt het erg jammer dat er geen stimulering meer is. Hij is nu voorzitter van één van de Duurzame Chemie Ontwikkeling (DCO) platforms. Deze platforms hebben als doelstelling verschillende disciplines bij elkaar te brengen: universiteiten, industrie en kennisinstituten. Het betreft vooral onderzoek naar vernieuwbare materialen en functionele polymeren. Voor een deel is het dus mogelijk om het door TDO bij de start gestimuleerde onderzoek op deze manier voort te zetten.

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Driving rain on building envelopes The measurements of driving rain on the west façade of the Main Building showed much variation for all observed the reference wind and rain quantities. A traditional empirical model (Lacy 1965) was applied to the data. We presented an improved empirical model, by which the wind direction and position on the façade are explicitly taken into account. Only with the improved model we could estimate quite accurate values of maximum driving rain intensities.

Promotors: Prof.ir. J.A. Wisse and Prof.dr.ir. K. Kopinga Copromotor: Dr.ir. M.H. de Wit Department of Architecture, building and planning

The wind at the experiment site was simulated by a standard k-ε model, and the results compared well with the measurements. The model, and the results compared well with the measurements. The applied model for driving rain takes drop trajectories (including drop dispersion due to wind turbulence) and raindrop spectra into account. The simulated driving rain intensities on the two positions on the west façade compared rather well with our measurements of driving rain. We discussed the aspects which should be dealt with to obtain reliable simulation results.

Fabien van Mook - 2003 - Department of Building and Architecture Driving rain is rain that is carried by the wind en driven onto the building envelope (façades and roofs). It is a complex phenomenon of falling raindrops in a turbulent flow around a building. It is one of the important climatological factors which determine long-term use and durability of building envelopes. We started the present study because the adequacy of the measurement techniques for driving rain in literature (from 1937 onwards) was doubted, and because, since the beginning of the 1990s, computational fluid dynamics made simulations of the complex phenomenon of driving rain – and hence a better understanding of it- possible. We developed a driving rain gauge which we improved by addition of a turning wiper. We tested it in an international comparison experiment in full-scale on the west façade of the Main Building of the Eindhoven University of Technology. The results indicated that out improved driving rain gauge is an accurate and reliable instrument, and that one may measure approximately half of the actual driving rain amount by an unimproved, traditional driving rain gauge. We formulated design rules for driving rain gauges. The full-scale experiments resulted in a unique series of continuous wind, rain and driving rain measurements during 24 months. Raindrop spectra with a disdrometer were measured during 3 months too. The measurements are detailed (data at 5 minute intervals were provided) and are available for future research.

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Radon transport in Autoclaved Aerated Concrete A probably cause of such flows is the presence of cracks. Inspection of the AAC cylinder and measurements on cracked and uncracked samples of AAC show that about half of the air flow goes through visually present cracks. This, however, only partly explains the results of the parallel-media model. There must still be a considerable part of the preferential flow in the visually uncracked, bulk material. Microcracks and mechanical dispersion are among the probable causes for this behaviour.

Promotors: Prof.ir. N.A. Hendriks and Prof.dr. R.J. de Meijer Copromotor: Dr.ir. W.H. van der Spoel Department of Architecture, building and planning Department of Applied Physics

Further research is required to understand the transport of radon in building materials and their contribution to the radon in Dutch dwellings. One of the aspects such research should focus on is the relation between the production and transport of radon in building material and its microscopic structure.

Michel van der Pal - 2004 - Department of Building and Architecture Radon in Dutch dwellings results, according to estimations of the WHO, in 800 cases of lung cancer per year. Limits set by the Dutch government tells this amount should be reduced. To be able to reduce radon concentrations, knowledge of the origin of radon in Dutch dwellings is required. Based on the second national radon survey, the building materials contribute about 70% to the total radon concentration in Dutch dwellings. However, when measuring the radon exhalation rate of building materials, a contribution of less than 20% is estimated. This research aims at gaining insight into the cause of this discrepancy by comparing measurements on the generation and transport of radon in autoclaved aerated concrete with model calculations based on independently measured parameters. To measure the transport of radon in AAC an experimental set-up has been developed. This set-up contains a cylinder of AAC placed in a stainless-steel cylindrical vessel of which various parameters, such as pressure, relative humidity, flow rate and temperature, can be controlled. A large discrepancy between the measurements and the model calculations is found for combined advective and diffusive transport of radon when representing AAC as a homogeneous material. A significantly better agreement is achieved when the AAC was represented as a material consisting of two parallel media, both with their own volume and permeability. The results of the parallel-media model indicate preferential flow.

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Physical and sustainable/technical optimization of the IFD today-apartment building system and the demounting phase embody the largest part of the environmental burden, the use phase has only a small contribution to the environmental burden. As a consequence prolonging service life will cause a much higher environmental burden while this is not the actual situation. All together it can be said that LCA in building at this moment is not completely true to the actual situation. To come to a more accurate way of LCA, the problem with the service life has to be solved. The Factor Method, an ISO standardised way of service life prediction will be used. With some alterations to include functional service life as well as technical service life, this method gives a closer estimation of the needed service life. Liability to trends as well as the complexity of building parts are incorporated in this kind of service life prediction. To enhance the reliability statistics will be used . That way a IFD building can be compared with a traditional building, with the specific extra’s an IFD-building has to offer rewarded (and not as a penalty). The research will point out the influence of time in Life Cycle Assessment and how to conduct a LCA so in the future these calculations can be done with more accuracy and optimisation of the IFD system can be achieved. Only then an accurate LCA comparison between traditional buildings and IFD buildings can be made.

Promotors: Prof.ir. N.A. Hendriks and Prof.ir. J. Westra Department of Building and Architecture

Haico van Nunen - lopend - Department of Building and Architecture There is a difference between Industrial Flexible and Demountable (IFD) building and the traditional way of building. For one, the flexibility in a IFD is higher. Because of this flexibility it is easier to adapt a building to the specific needs of an occupant. The start of this research lies in the assumption that IFD building will be better for the environment than traditional building. An environmental comparison between the two should prove this. During the research some gaps in the environmental calculation methods, or Life Cycle Assessments (LCA), are discovered. These gaps form a barrier to the calculation of a LCA for IFD buildings. The most important gap is the factor of time. To conduct a LCA, all the materials necessary throughout the complete service life of the building have to be taken into account, from cradle to grave. At this moment this is done by using reference service lives based on technical criteria. This is not in accordance with the actual situation, especially not in IFD buildings where the presence of flexibility will cause more changes than in traditional buildings. It is not the product that indicates the technical service life is over, but it is the occupant that decides the functional service life is over (it doesn’t satisfy the occupants wishes any longer). These kind of changes can not be taken into account in current LCA’s.

The end of this PhD research is planned for July 2005.

There are other aspects that influence the outcome of a LCA. Most current computer programs use a linear development of environmental burden through time. This is incorrect, because the building phase

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Intelligente netten Prof.dr.ir. Jan Blom Faculteit Elektrotechniek

Bij de faculteit Elektrotechniek worden een aantal projecten gestimuleerd door Technologie voor Duurzame Ontwikkeling (TDO). Eén project is al afgerond: het onderzoek van Dr.ir. Wilfried Hoeben. Momenteel zijn nog drie promovendi bezig met hun onderzoek, namelijk Ir. Konstantin Bionov, Ir. Paul Wingelaar en Ir. Sreejet Nair. In het proefschrift van Hoeben wordt de afbraak beschreven van organische verbindingen in waterige oplossing met behulp van gepulste corona-ontladingen. Deze elektrische ontladingen zijn toegepast in de gasfase boven de oplossing van de doelcomponent. Ten gevolge van de extreem hoge elektrische veldsterkte (ongeveer 200 kV/cm) aan de kop van de coronaontladingskanalen, worden aldaar aanwezige moleculen van het diëlectricum gedissocieerd, geëxciteerd of geïoniseerd. In vochtige lucht worden aldus de volgende reactieve deeltjes geproduceerd: hydroxylradicalen, zuurstofatomen, ozon, stikstofmetastabielen, ionen en UV fotonen. De gepulste corona technologie is gedetailleerd getoetst op de modelstof fenol (hydroxybenzeen), een belangrijke precursor in de organisch-chemische synthese. Tevens is de degradatie van enkele andere modelcomponenten bestudeerd, te weten atrazine (herbicide), malachiet groen (kleurstof ) en dimethyl sulfide (geurcomponent). Uit de experimenten is een gunstige elektrodenconfiguratie naar voren gekomen. Naast de oxidatie van doelcomponenten is ook de productie van oxidatoren onderzocht. De productie van hydroxylradicalen in waterige oplossing is bestudeerd met fluorescentie spectrometrie in combinatie met de fluorescerende moleculaire probe coumarine-3-carboxylzuur (CCA); tevens is in-situ elektron spin resonantie

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Intelligent networks

Nair is continuing this research. This second project is also supported by TDO and

Prof.dr.ir J.H. Blom, Department of Electrical Engineering

partly by DSM. The other two PhD students both work in the group ‘electromechanics

At the Department of Electrical Engineering several projects are being partly financed

and power electronics’ (EPE) at the Department of Electrical Engineering. One PhD

by the TU/e incentive arrangement for sustainable development (technologie voor

student, Boinov, is working on ‘energy-efficient controlled induction motor drives for

duurzame ontwikkeling (TDO)). One project has already been finished: the research

fuel cell power systems’ and the other, Wingelaar, is working on power electronic energy

of Dr.ir. Wilfried Hoeben. Three PhD students are still doing research: Ir. Konstantin

management of a small electricity generation system based on biomass and fuel cells.

Bionov, Ir. Paul Wingelaar and Ir. Sreejet Nair. Prof.dr.ir. Jan Blom, professor of electrical energy supply and also dean of the Electrical One research area is about so-called 'pulsed corona'. This technique is used to clean

Engineering department, discusses the link between electrical energy supplies and

gasses by means of the breaking of molecules or the influencing of chemical reactions.

sustainability. Nowadays, there are three trends visible in society: 1) a social trend, 2) an

In this way, it is possible to break down for example unpleasant or poisonous gasses into

economic trend, and 3) a technological trend.

harmless gasses. Hoeben was the first PhD student in this research area. Now, Ir. Sreejet

toegepast met behulp van de spin trap 5,5-dimethyl-1-pyrroline N-oxide (DMPO). UV absorptiespectrometrie is toegepast voor de kwantitatieve analyse van ozon. Het onderzoek naar pulsed corona is met name gericht op het reinigen van gassen. Hierbij worden dus moleculen afgebroken of chemische reacties beïnvloedt. Zo is het mogelijk bijvoorbeeld vervelend geurende of giftige gassen af te breken in onschuldige gassen. Nadat Hoeben de eerste aanzet gegeven heeft, is nu de promovendus Ir. Sreejet Nair bezig met het vervolgproject. Dit project wordt ook deels door TDO gefinancierd, daarnaast ook deels door DSM. De andere twee promovendi die nog bezig zijn, werken beide in de groep ‘technologie voor de conversie van elektrische in mechanische energie’ (electromechanics and power electronics EPE) bij de faculteit Elektrotechniek. Eén promovendus, Bionov, werkt aan energie-zuinige inductiemotoren voor brandstofcelsystemen en de ander, Wingelaar, aan elektrisch energie management van een kleinschalige systeem voor elektriciteitsopwekking gebaseerd op biomassa en brandstofcellen. Prof.dr.ir. Jan Blom, hoogleraar elektrische energietechniek en ook decaan van de faculteit Elektrotechniek, vertelt over het verband tussen elektrische energietechniek en duurzaamheid. In de huidige maatschappij zijn volgens Blom een drietal trendbreuken zichtbaar die duurzame ontwikkeling beïnvloeden, te weten: 1) een maatschappelijke trendbreuk; 2) een economische trendbreuk (de geliberaliseerde markt voor elektrische energie) en 3) een technologische trendbreuk.

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Intelligente netten

Volgens Blom moet een afweging gemaakt worden tussen: duurzame bronnen, duurzame energie of een duurzame samenleving. Van deze drie is de laatste de situatie die je in feite wil bereiken. Voor een duurzame samenleving is de maatschappelijke trendbreuk, zoals hierboven geformuleerd, het belangrijkst. Technologisch gezien zal een duurzame samenleving neerkomen op het vermijden van uitputting van bronnen en het recyclen van stofstromen. Technisch gezien moet het kunnen: energie blijft namelijk behouden, maar de kwaliteit van de energie neemt helaas af bij iedere omzetting. Elektrische energie is de enige energiedrager die je theoretisch met een rendement van 100% om kunt zetten in alle andere vormen van energie. Het wordt volgens Blom zaak te recyclen met een zo hoog mogelijk rendement. Daarbij is het ook van belang dat je energie efficiënt werkt, daarom is bijvoorbeeld het selectief reinigen met behulp van pulsed corona een goede optie. De duurzame samenleving vraagt in Blom’s optiek dus om elektrische energie, niet in de eerste plaats om duurzame energie. Wel is het zo dat vrijwel alle duurzame bronnen, bijvoorbeeld zon, wind en water, elektrische energie leveren. Kenmerkend is dat dit plaatsvindt op onregelmatige basis en bijvoorbeeld op kleinere schaal. De netwerkstructuur voor het elektrische energie-net moet dus zodanig ingericht worden dat het mogelijk is met deze specificaties elektrische energie aan te kunnen leveren aan het net. Dit geeft specifieke problemen die getackeld moeten worden. Volgens Blom neemt in alle scenario’s voor de energiehuishouding in de toekomst de vraag aan elektrische energie toe. Dit is bijvoorbeeld te vinden in het rapport van de KEMA from ‘source to service’.

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Blom thinks it is important to decide what you want: sustainable sources, sustainable

all sustainable sources, like water, sun and wind, can deliver electrical energy. Typically,

energy or a sustainable society? The latter, a sustainable society, is in fact what you

this only occurs irregularly and on a small scale. The structure of the network for the

really need. If a sustainable society is the goal, the social trend, as defined above, is

supply of electrical energy has to be arranged in such a way that it is suitable for these

most important. From a technological viewpoint, a sustainable society comes down to

specifications. Therefore specific problems have to be tackled.

avoidance of the depletion of sources and recycling of material flows. This might work, because energy is conserved. The quality of the energy however decreases. Electrical

According to Blom, all scenarios for the energy supply to households in the future show

energy is the only energy carrier of which the theoretical efficiency is 100% when

an increase in the demand for electrical energy. This is for example shown in the report

converted into all other energy forms. Blom thinks it is a matter of recycling and using

of KEMA: ‘from source to service’. By 2020 the energy demand will have doubled.

an efficiency that is as high as possible. So it is important to pay attention to energy

The greater part needs to be leveled out by increasing the amount of electrical energy.

efficient conversions. That is why selective cleaning such as by using a pulsed corona

From the point of view of chain optimization, electrical energy for static use and hydrog-

is such a good and sustainable option. In Blom’s point of view, a sustainable society

en for mobile use seem to be the best options In this context it is important to close the

demands electrical energy, so not sustainable energy in the first place. However, almost

chains by for example using waste heat for the heating of houses. This method is already applied in Moscow: the use of energy for heating is low there.

In 2020 wordt een verdubbeling van energievraag verwacht, waarvan het merendeel opgevangen dient te worden door de inzet van elektrische energie. Met het oog op ketenoptimalisering kom je uit bij een hoogwaardige energiedrager als elektrische energie voor statische toepassingen en waterstof voor mobiele toepassingen. Belangrijk is de ketens te sluiten door bijvoorbeeld gebruik van afvalwarmte van centrales voor verwarming van huizen. Dit gebeurt bijvoorbeeld in Moskou: het energieverbruik voor verwarming ligt daar laag.

The Department of Electrical Engineering is also participating in the Master’s track Sustainable Energy Technology (SET). Most attention is being focused on the problem of the integration of decentralized generation of energy in the network. For some time we have held on to the ‘economies of scale’ argument: the bigger a plant the better. However, for small-scale plants, optimization is a possibility. For example, ABB wants to introduce an optimized small-scale design on the market, but then in a large batch. Here, once again, sustainability has inspired research and education at the Department of Electrical Engineering.

De faculteit Elektrotechniek neemt ook deel aan de master track Sustainable Energy Technology (SET). Hierbij wordt vooral de aandacht gericht op het probleem van de integratie van decentrale opwekking in het net. Lange tijd is volgens Blom het ‘economies of scale’ argument vastgehouden: hoe groter de centrale hoe beter. Je kunt het echter ook van een andere kant bekijken: bij kleinschalige opwekking is het mogelijk een centrale te optimaliseren. Zo wordt bijvoorbeeld bij ABB gewerkt aan het op de markt zetten van een geoptimaliseerd kleinschalig ontwerp, maar dan in grote oplage. Het thema duurzaamheid is een inspiratiebron geworden voor zowel onderzoek als onderwijs aan de faculteit Elektrotechniek.

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Intelligente netten

47


Pulsed corona-induced degradation of organic materials in water dimethyl sulfide (odor component). A favourable electrode configuration has been derived from the experiments. In addition to the oxidation of model compounds, also the production of oxidizers has been investigated. The production of hydroxyl radicals in aqueous solution has been studied by fluorescence spectrometry in combination with the fluorescent molecular probe coumarin-3-carboxylic acid (CCA); also in-situ electron spin resonance has been applied using the spin trap 5,5-dimethyl-1-pyrroline N-oxide (DMPO). UV absorption spectrometry has been applied for the quantitative analysis of ozone.

Promotors: Prof.dr. W.R. Rutgers and Prof.dr.ir. C.A.M.G. Cramers Copromotor: Dr.ir. E.M. van Veldhuizen Department Electrical Engineering, Electrical Energy Systems group Department of Chemical Engineering, Instrumental Analysis group Department of Applied Physics, Elementary Processes in Gas Discharges (EPG)

The conversion level, conversion efficiency and oxidation mechanisms of the model compound phenol have been investigated. Conversion and oxidation pathways have been determined by means of the liquid chromatographic techniques reversed-phase HPLC and ion-exclusion chromatography; in addition, IonSpray and electron-impact mass spectrometry have been applied. Also, phenol oxidation has been studied in-situ using laser-induced fluorescence spectroscopy. The gas phase over the oxidized aqueous phenol solution has been analyzed by infrared spectroscopy and an aldehyde screening test. From an environmental point of view, Microtox ecotoxicity tests and total organic carbon measurements have been performed on fresh and oxidized phenol solutions. Reaction mechanisms have been derived for phenol oxidation by hydroxyl radicals, oxygen and ozone.

Wilfried Hoeben - 2000 - Department Electrical Engineering Since recently, some advanced oxidation processes (AOP’s) have been applied for the degradation of harmful materials, as alternative to microbiological waste water treatment or as add-on technology. The AOP focuses on the degradation of persistent toxic materials by radical-induced oxidation; for this purpose, halogen- and metal-free oxygen-based oxidizers are utilized, especially hydroxyl radicals. By advanced oxidation a persistent toxic compound is converted into microbiologically degradable products, or is even mineralized to carbon dioxide, water and -depending on the nature of the target compoundinorganic ions like e.g. nitrate, sulfate and phosphate. Hydrogen peroxide/UV, ozone/UV and wet oxidation AOP’s have already been applied on modest scale; the status of electrical discharge, electronbeam and photocatalytic AOP’s is still experimental. This thesis describes the degradation of organic materials in aqueous solution by pulsed corona discharges. These electrical discharges have been applied in the gas phase over the target compound solution. As a result of the extremely high electric field strength (about 200 kV/cm) at the head of the discharge channels, locally present molecules of the dielectric are dissociated, excited or ionized. In humid air the following reactive species are produced: hydroxyl radicals, oxygen atoms, ozone, nitrogen metastables, ions and UV photons. The pulsed corona technology has been studied in detail using the model compound phenol (hydroxybenzene), which is an important precursor in organic chemical synthesis. Also the degradation of some other model compounds has been studied viz. atrazine (herbicide), malachite green (dye) and

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Intelligente netten

The conversion of atrazine has been performed by reversed-phase HPLC. Dimethyl sulfide has been oxidized in the gas phase and the conversion has been determined by gas chromatography. The decolorization of malachite green due to oxidation by corona has been determined for several electrode configurations using absorption spectrometry. The most efficient electrode configuration consists of a multipin anode situated in the gas phase over the aqueous solution of the target compound, while the cathode is dielectrically separated from the anode. In this way an effectively dimensioned plasma is produced and energy dissipation due to vapour formation is avoided. During oxidation of aqueous solutions of the fluorescent molecular probe CCA, the fluorescence intensity appears to increase linearly with the oxidation time, which implies a constant hydroxyl radical production rate in water. Calibration of the fluorescence intensity as a function of the amount of hydroxyl radicals added using hydrogen

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Energy-Efficient Controlled Induction Motor Drives for Fuel Cell Power Systems peroxide and CCA has appeared to be impossible. Identification of hydroxyl radicals by in-situ ESR has been unsuccessful, although the spin trap DMPO has been utilized to produce a stable adduct. The ozone concentration in air over water increases with the applied load voltage, while positive corona produces more ozone than negative corona. The measured ozone production efficiency is about 40 g/kWh which is high, because the ozone has been produced in humid air. During oxidation the ozone concentration over aqueous phenol solutions is significantly lower than the ozone concentration over deionized water, which is explained by the reaction of ozone with phenol. The oxidation of phenol in aqueous solution by pulsed corona discharges in air yields a complex mixture of oxidation products. Polyhydroxybenzenes are produced, which yield aliphatic aldehydes and carboxylic acids by ring-cleavage. The derived oxidation pathways explain the formation of polyhydroxybenzenes and aliphatic polyfunctional hydrocarbons. The intermediate oxidation products are more harmful than phenol, therefore thorough oxidation progress is required; the temporal toxicity increase is no specific problem occurring from corona technology, but is inherent to oxidation. Except for small amounts of carbon dioxide, no other gaseous phenol oxidation products have been identified. This is in accordance with an observed nearly constant total organic carbon level of the aqueous solution during oxidation. There appear to be large differences between oxidation products obtained by corona in air and corona in argon. By corona in argon mainly hydroxylation of phenol takes place, while in the presence of air also ring-cleavage takes place. The measured efficiency at 24% phenol conversion by corona in air is about 22 nanomol/J, which corresponds to 7.5 g/kWh. Atrazine and malachite green are very stable compounds, which appears from the conversion efficiency: the efficiency of atrazine is 0.6 g/kWh at 27% conversion, while the efficiency of malachite green is 0.4 g/kWh at 24% absorption decrease at λabs=590 nm with regard to the most favourable electrode configuration. On the contrary, dimethyl sulfide is readily converted.

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Intelligente netten

Promotor: Prof.dr.ir. A.J.A. Vandenput Copromotor: Dr. J.L. Duarte Department of Electrical Engineering

Paul Wingelaar - lopend - Department of Electrical Engineering Although fuel cells are known for quite a long time, the first one is being demonstrated in 1843, the interest of using these green power generators in everyday applications is relatively new. Since the price of Polymer Electrolyte Membrane Fuel Cells (PEMFC) has dropped, the interest of implementing these energy generators grows. To provide the fuels to the fuel cell, one can choose for pure hydrogen, which can be the waste product of a chemical process, or it can be made by electrolysis of water on industrial scale. It is also possible to gain hydrogen from 'normal' fuels like methanol or diesel, but the challenge for sustainability is to win hydrogen from a green energy source like biomass. The overview of the system gives the desired implementation of the energy generator system based on biomass and fuel cells. The system can be connected to the grid, or can be used in island operation. It is of crucial importance to know which time constants are involved in the energy generator. In order to design an optimized power electronic device for coupling the fuel cell system to the grid, it is necessary to characterize the fuel cell system in combination with the fuel processor. A test-setup for the characterization of the fuel cell is used. This test-setup is capable of determining the steady state behavior and the dynamic response of the fuel cell system. Also a biomass / fuel cell emulator prototype is available. The characterized fuel cell system can be emulated with this device, leading to a good design tool without using a biomass reformer and fuel cell system.

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Corona Plasma for Tar removal reactions are outlined. Radical yields could be estimated at various conditions and for different gas compositions. An increase in radical utilization was observed in synthetic fuel gas at higher temperatures.

Promotoren: Prof.dr.ir. J.H. Blom and Prof.dr.ir. A.A.H. Drinkenburg Co-promotor: Dr.ing. A.J.M. Pemen

Energy consumption for naphthalene removal decreased with increasing temperature, indicating improvement in the overall process economics. From a value of 400 J/L at 200 0C, the energy consumption could be reduced to 200 J/L at 400 0C. Naphthalene decomposition pathways could be identified and these were supported by both calculations and experimental evidence. Based on these experiments, optimum operating conditions are obtained for a tar removal system using corona discharges. Further more, from the available information, a corona plasma device is conceived which can used not only for tar removal but also for cleaning gasification gas from other undesired components. This enables to enhance flexibility of operation of a gasifier and to improve the overall process economics as well.

Department of Electrical Engineering, Electrical Power Engineering Department of Chemical Engineering

Sreejit Nair - lopend - Department of Electrical Engineering Biomass gasification is one of the more efficient ways of utilizing it. One of the problems associated with it is the production of tar. In this project, we have investigated tar removal by means of non-thermal plasma, particularly pulsed corona plasma, as an alternative approach to catalytic or thermal tar removal. This technique, if successful, could enable combined tar, dust and particulate removal in single equipment.

We have identified the major mechanisms for tar removal by pulsed corona discharges. Research in 2004 will focus on further minimizing the costs for corona processing: - An novel method for corona plasma generation will be evaluated, based on a AC/DC power supply. This can significantly reduce the investment costs for corona tar removal. - Combined corona and catalytic techniques will be studied, in order to enhance utilization of the produced radicals for tar removal and to reduce radical termination reactions. - Corona processing allows the combined removal of tars and e.g. chlorine and sulfer compounds. This will be further elaborated.

Proof of concept studies were done on a real gasifier to verify this idea. Results from field tests on a real wood gasifier indicate that tar molecules can be broken down and simultaneously dust particles can be removed from the gas stream. Additionally, the experiments demonstrated that pulsed corona could be sustained in a large volume and in the present challenging operating conditions. A setup was constructed for performing high-temperature experiments. The design of the setup can be used as a concept for an industrial prototype and for scaling up the reactor. Experiments were performed: (i) to identify chemical mechanisms and develop a kinetic model, and (ii) to determine energy requirements for decomposition of naphthalene at various temperatures.

We demonstrated the feasibility of pulsed corona for biogas conditioning. Transfer of technology to industry is foreseen. Demonstration projects will be highly desirable. We plan to shift our research more from gas cleaning towards plasma assisted gasification. Novel concepts for combined thermal/non-thermal plasma generation and arrayed plasmas that have a distribution that is well controllable in space and time are under development. These plasmas can be generated in a proper region inside a biomass gasifier and will enhance the gasification process.

Primary mechanism for tar removal in synthetic fuel gas was identified to be oxidation, initiated by CO2 dissociation. Termination of reactive radicals leads to increased energy requirements of the process. These findings are supported by numerical calculations and main competitive

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Intelligente netten

53


Energy-Efficient Controlled Induction Motor Drives for Fuel Cell Power Systems optimization of the compressor drive operation profiles, and, on the other hand, to maintain the efficiency of the electrical drive at the appropriate level with respect to mentioned motion profiles through the implementation of the IM energy-efficient control strategies.

Promotor: Prof.dr.ir. A.J.A. Vandenput Copromoter: Dr. E.A. Lomonova Department of Electrical Engineering

At present time, the research is mainly focused on the theoretical and experimental investigation related to the system with the centrifugal compressor and a high-speed IM drive including the following tasks: -

Konstantin Boinov - lopend - Department of Electrical Engineering

-

The main goal of the research project is to provide the energy optimal operation of an autonomous fuel cell (FC) power system with integrated induction motor (IM) drives.

-

The optimal FC system operation requires the appropriate air management, which is provided by an air compressor driven by an electrical drive. Traditionally the task of air management in compressor systems is solved with the use of a constant speed drive (as a prime actuator) and a set of controllable valves. Such a configuration leads to the increasing in the level of power losses and, accordingly, decreasing in the total system efficiency.

The static and dynamic measurements on the compression system (high-speed IM, centrifugal air compressor, piping system, data acquisition (DAQ) and control system). The implementation of the IM high-performance control (indirect FOC combined with an adaptive control approach, e.g. Sliding Mode Control). Active surge control implementation by means of FOC IM. Optimization of the energy efficiency of the system with the high-speed IM and the centrifugal compressor with respect to the desired operation profile (balance of plant of the FC system operation).

Reporting and publication the results, writing the PhD thesis.

The replacement of the valve regulation by a variable speed drive allows the performing the more flexible control of the system and improving its efficiency by the accurate adjustment of the system operation regimes, and, therefore, avoiding the undesirable power consumption. The induction motor drive is regarded as one of the best candidates for the implementation as a FC compressor drive due to its advantages, such as: low cost, simple construction and high reliability. Meanwhile, the IM drive performance, in its turn, is dependent on the system operation regimes. Thus, the current project has the dual goal: on one hand, the improvement of the total system efficiency via the

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Intelligente netten

55


Schone producties Prof.dr. Rutger van Santen Faculteit Scheikundige Technologie

Het onderzoek in de katalyse-groep van Prof.dr. Rutger Van Santen gaat met name over het verwijderen van stikstofhoudende verbindingen uit water en gas. Hierbij moet voornamelijk gedacht worden aan ammoniak, en dan zowel de uitstoot van landbouw als ook van de industrie. In het kader van een samenwerking tussen Technologie voor Duurzame Ontwikkeling (TDO) en Schuit Katalyse Instituut (SKI) zijn een viertal AIO’s en twee post-docs gefinancierd: de AIO’s zijn Dr.ir. Arnoud de Vooys, Dr.ir. Lu Gang, Dr.ir. Rob Hanssen en Dr.ir. Dariusz Sobczyk. Daarnaast hebben de post-doc’s Dr.ir. Ukropec en Dr.ir. Frechard ook gewerkt aan dit onderzoeksonderwerp. Een korte beschrijving van elk van de vier AIO projecten geeft een aardig beeld van de gevolgde onderzoekslijn. Het proefschrift van Dr.ir. Arnoud de Vooys gaat over de elektrochemische oxidatie en reductie van kleine anorganische stikstofhoudende moleculen. De reden voor dit onderzoek is de milieuproblemen die veroorzaakt worden door, met name, nitraat (NO3-), stikstofmonoxide (NO) en ammoniak (NH3). Deze stoffen moeten verwijderd worden uit afval- en drinkwater door ze om te zetten in ongevaarlijk stikstof (N2). Het is heel belangrijk dat stikstof het enige product is, omdat andere producten soms giftiger zijn dan de uitgangsstof. De selectiviteit van de omzettingsreactie is daarom één van de hoofdthema’s van dit proefschrift, samen met de activiteit (de snelheid van de reactie). In de industrie wordt vaak een katalysator gebruikt om de reactie te sturen naar de juiste producten, en ook in dit proefschrift worden katalysatoren gebruikt. De gebruikte katalysatoren zijn de edelmetalen platina (Pt), palladium (Pd), rhodium (Rh), iridium (Ir), ruthenium (Ru) en

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Cleaner production: catalysis for end-of-pipe cleaning up Prof.dr. R.A. van Santen, Department of Chemical Engineering Removal of nitrogen-containing compounds from water and gas is the main focus of the research in the catalysis group of Prof.dr. R.A. Van Santen. The nitrogen-containing compound ammonia (NH3) is of particular interest. This component is a result of pollution caused both by industry and agriculture. Through cooperation between the bureau of sustainable energy (TDO) and the catalysis institute of Schuit (SKI), a set of four PhD projects and two post-doc positions are being financed. The PhD students are Dr.ir. Arnoud de Vooys, Dr.ir. Lu Gang, Dr.ir. Rob Hanssen and Dr.ir. Dariusz Sobczyk. Simultaneously, the post-doc’s Dr.ir. Ukropec and Dr.ir. Frechard worked on the same research subject. A short description of each project is found in the summaries added later on in this section. These descriptions give a good impression

goud (Au), en in sommige gevallen is ook zilver (Ag) en koper (Cu) gebruikt. Deze metalen zijn gekozen omdat ze niet roesten of oplossen in water (wat de reden is dat de metalen edel genoemd worden). Het doel van dit proefschrift is te onderzoeken hoe op moleculair niveau de reacties van kleine stikstofhoudende moleculen en ionen verlopen, wat de intermediairen zijn en wat de rol van de katalysator is. Het onderzoek van Dr.ir. Lu Gang gaat over selectieve katalytische oxidatie. Selectieve katalytische oxidatie (SCO) van ammoniak met zuurstof naar stikstof en water is bekend als een doelmatige oplossing voor de vermindering van de NH3 uitstoot. Tussen de katalysatoren die genoemd worden als mogelijke materialen voor dit proces, zijn edelmetaal katalysatoren zoals Pt, Ir heel actief bij lage temperatuur maar niet selectief naar stikstof. Bovendien produceren ze significante hoeveelheden N2O. Metaaloxides zoals Co3O4, MnO2, CuO, Fe2O3, V2O5 en MoO3 zijn ook actief voor ammoniak oxidatie maar de activiteit is niet hoog genoeg om te worden toegepast als industriële katalysator. Het onderzoek van Gang is specifiek gericht op de ontwikkeling van een nieuwe, actieve en selectieve katalysator voor de lage temperatuur selectieve oxidatie van ammoniak naar stikstof. Het proefschrift van Dr.ir. Rob Hanssen beschrijft de ontwikkeling van een nieuwe methodologie voor de synthese van microporeuze metaalsilicaatkatalysatoren op basis van oxidatie bij hoge temperatuur van metaalsilsesquioxaanvoorlopers (voorgevormde complexen). De activiteit en selectiviteit van heterogene katalysatoren zijn over het algemeen afhankelijk van

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Schone produkties

de metaaldispense (deeltjesgrootte), structuur (vorm en morfologie), metaalsamenstelling, en de interactie tussen het metaal en de drager. Aan de andere kant zijn de eigenschappen van katalysatoren afhankelijk van de bereidingsmethode. Verschillende methoden voor de bereiding van heterogene metalen katalysatoren zijn ontwikkeld om een hoge activiteit en selectiviteit te verkrijgen. Ondanks het feit dat deze methoden normaal gebruikt worden voor de productie van commerciële katalysatoren, geven ze niet altijd voldoende controle over de verdeling van de deeltjesgrootte op de metaalcompositie. Het onderzoek van Dr.ir. Dariusz Sobczyk had als doelstelling om het reactiemechanisme van katalytische omzetting van ammoniak op platina te bestuderen bij bepaalde reactiecondities: lage temperaturen, atmosferische druk en constante stroom. De aanzet om ammoniak om te zetten naar milieuvriendelijke producten, stikstof en water, kwam uit de noodzaak om industriële afvalstromen van ammoniak te zuiveren. Op platina gebaseerde katalysatoren geven goede perspectieven om bij lage temperaturen ammoniak naar stikstof en water om te zetten. Deze katalysatoren hebben een hoge activiteit en zijn stikstof selectief, hoewel ze vrij snel deactiveren. Volgens Van Santen zit het nut van de TDO stimulering hierin: de industrie wil geen geldkostende milieuvriendelijke oplossingen, en daardoor is met name bij het opstarten van dergelijk onderzoek de directe industriële steun zeer beperkt. Op dit punt is TDO dus heel waardevol. Behalve directe resultaten zoals in de vorm van patenten, publicaties, proefschriften en

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of the sort of research that is performed in this group financed by the TU/e incentive

Except from directly applicable knowledge, more insight is gained into the use of

arrangement for sustainable energy (TU/e stimuleringsregeling van technologie voor

electrolysis for the conversion of ammonia into nitrogen. For example, new conditions

duurzame ontwikkeling (TDO)).

are discovered for the conversion of nitrates. In a project in cooperation with the National Research school of Catalysis, enzymes are being used for the conversion of

The support from industry for cost-saving, environmentally-friendly solutions is limited

ammonia (NH3). When choosing the right enzymes, the conditions of the environment

according to Van Santen. So especially for the start of such research the direct support

can remain unchanged. Fundamental research in this area is performed together with

from industry is restricted. That is where TDO is valuable. Apart from direct results such

the Deutsche Forschungsgemeinschaft. In Eindhoven numerical calculations are per-

as patents, publications, theses and students, other developments are initiated by the

formed, while in Hannover the experimental part is studied.

supported projects as well. For example, the projects led to a proposal for an industrial process of removal of ammonia. Shell tested this process using practical conditions. This

In short, according to Van Santen sustainability is an essential motive for technology

example makes clear why the support at the start of the research is useful: in this case it

research.

has been proven that this technique will have relevance for industry.

studenten zijn er ook andere ontwikkelingen in gang gezet door de gestimuleerde projecten. Zo leidde de projecten bijvoorbeeld tot een voorstel voor een industrieel proces voor ammoniakverwijdering. Binnen Shell is dit proces onder praktische omstandigheden getest. Duidelijk een voorbeeld dus van het nut van de ondersteuning bij het opstarten van het onderzoek: in dit geval kon het bewijs worden geleverd dat de techniek uiteindelijk relevantie zal hebben voor de industie. Behalve direct toepasbare kennis is er ook meer inzicht verkregen in de kennis van elektrolyse voor het omzetten van ammoniak naar stikstof. Zo zijn er ook nieuwe condities ontdekt waarbij nitraten omgezet worden in stikstof. Nu wordt er in een project samen met de National Research School Catalyse gewerkt om met behulp van enzymen ammoniak om te zetten. Door de juiste enzymkeuze hoef je de omgevingscondities niet aan te passen. Momenteel wordt in samenwerking met de Deutsche Forschungs Gemeinschaft gewerkt aan fundamenteel onderzoek op dit gebied. In Eindhoven worden de numerieke berekeningen uitgevoerd en in Hannover wordt de experimentele kant belicht. Kortom, duurzaamheid is in de ogen van Van Santen een wezenlijke drijfveer voor technologie.

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Electrocatalytic Reactions of Inorganic Nitrogen-containing Compounds palladium in the selective reduction of NO to N2, other metals produce different products. When sulfate (SO42-) adsorbs at the surface there is less room for NO3- to adsorb, which lowers both the activity and the selectivity to N2. The trends in activity and selectivity are explained in terms of the amount of NO3- and NO near the surface. Since the reduction of NO is a crucial step in the reduction of NO3-, and is an interesting reaction in its own right, a systematic study was performed to determine the mechanism of the NO reduction. Since platinum shows the best reproducibility, this metal was chosen to perform an in-dept study (chapter 3). Both the reduction of NO in the presence of NO in the solution and the reduction of adsorbed NO in a clean electrolyte were investigated.

Promotors: Prof.dr. J.A.R. van Veen and Prof.dr. R.A. van Santen Copromotor: Dr. M.T.M. Koper Department of Chemical engineering Inorganic Chemistry and Catalysis

Arnoud de Vooys - 2001 - Department of Chemical engineering

The adsorbate reduction takes place through a combined proton/ electron transfer in equilibrium followed by a rate determining chemical step. NH3 is the only product in the absence of NO in solution. The reduction in the presence of NO in the solution at high potentials yields N2O as the only product. The mechanism of this reaction is not of the Langmuir-Hinshelwood type, but rather involves the combination of a surface-bonded NO molecule with a NO molecule from the solution and a simultaneous electron transfer. A protonation takes place prior to this step. In alkaline solutions a chemical step appears to be partially rate determining. The continuous reduction of NO at low potentials yields mainly NH3. The mechanism of this reaction is the same as for the adsorbate reduction.

In this thesis the reduction and oxidation reactions of small inorganic nitrogencontaining molecules and ions is investigated. The main motivation of this research is to counteract environmental problems caused by especially nitrate (NO3-), nitric oxide (NO) and ammonia (NH3). The desired product of these reactions is the environmentally benign N2. Since all other products are toxic, the selectivity of the reactions will be a main theme, next to the rate of the reactions. In industry, catalysts are often used to “steer” the reaction to the right products, and in this thesis we will also use catalysts. The catalysts will be noble metals (platinum (Pt), palladium (Pd), rhodium (Rh), iridium (Ir), ruthenium (Ru), gold (Au) and sometimes silver (Ag) and copper (Cu)), since these do not rust or dissolve in acidic and alkaline solutions. The objective of this thesis is to understand the reactions of NO3 -, NO and NH3 at a molecular level, the role of the catalyst, and to search for general features by which these reactions can be described.

In chapter 4 it is shown that the behaviour of the other transition metals (Pd, Rh, Ru, Ir and Au) is very similar to that of platinum, suggesting that the reaction schemes are essentially the same. This is true for both for the reduction of adsorbed NO and for the continuous NO reduction. In the presence of NO all metals show a high selectivity to N2O at high potentials and a high selectivity to NH3 at low potentials, whereas N2 is formed at intermediate potentials (although gold forms mainly N2O, and little NH3). Like platinum, the mechanism that leads to N2O is believed to involve the formation of a NO-dimer intermediate. The reduction of adsorbed NO leads on all metals only to formation of NH3, no N2O or N2 are formed, and also in this case is the mechanism similar to that found for platinum. The formation of N2, produced at potentials between the formation of N2O and NH3, most likely takes

Noble metals themselves are inactive in the reduction of NO3-, copper has to be added to get an active catalyst. The role of copper promotion and of palladium as the noble metal is investigated in chapter 2. In acidic electrolytes the activity increases linearly with copper coverage, showing that copper is active in the first step. The intermediate of this reaction is NO, so the first step of the reaction is the reduction of NO3- to NO. When the amount of palladium at the surface is increased, i.e. the coverage of copper decreased, the selectivity to N2 increases. This is attributed to the high activity of

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place by the reduction of previously formed N2O. Palladium has the highest activity in the N2O reduction and therefore also the highest selectivity in the reduction of NO to N2.

formed from ammoniacontaining electrolyte on gold and palladium electrodes using SERS. On gold, a band at ca. 365-385 cm-1 is observed, which is identified as the Au-NH3 vibration based of the frequency redshift observed upon deuteration (replacement of H2O with D2O). The Pd-NH3 vibration is observed at 440-455 cm-1, which also shows the H/D redshift. On palladium, a transfer of the deactivated electrode to an ammonia-free electrolyte yielded a vibrational band at 455-465 cm-1. The near-zero H/D frequency shift identifies this vibration as the Pd-N vibration, without any hydrogen atoms attached to the nitrogen.

Chapter 5 deals with the oxidation of NO on Pt, Pd, Rh, Ir, Ru and Au. The oxidation in the presence of NO takes place in two steps. In the first step HNO2 is formed, in a mechanism where the first electron transfer is rate determining. The rate of this reaction is independent of the metal, indicating that no strongly adsorbed species are involved in the rate-determining step. In the second step NO3 - is formed, and, opposed to the formation of HNO2, this reaction is metal dependent. The oxidation of adsorbed NO is again metal-independent, suggesting a link between continuous oxidation and adsorbate oxidation. Both in the oxidation in the presence of NO and in the adsorbate oxidation surface oxides might play an important role, this should be investigated using non-electrochemical techniques, like surface enhanced raman spectroscopy (SERS). The relationship between the activity for ammonia oxidation and the intermediates formed during the reaction on Pt, Pd, Rh, Ir, Ru, Au, Ag and Cu is discussed in chapter 6. The activity in the selective oxidation to N2 is directly related to the nature of the species at the surface: the electrode is active if NHads (or NH2,ads) is present, and deactivates when Nads is present. The potential at which NHads or Nads are formed is metal dependent. The observed trend in the strength of adsorption of Nads is Ru> Rh> Pd> Ir> Pt>> Au,Ag,Cu. This trend corresponds well with the trend observed in the calculated heat of adsorption of atomic nitrogen, with only iridium being an exception. Platinum is the best catalyst for this reaction because Nads is formed at high potential, compared to the other transition noble metals, but NHads seems to be stabilized rather well. Gold, silver and copper do not form NHads or Nads, and show only an activity when the surface becomes oxidized. The metal electrodissolution is enhanced by ammonia under these conditions. Most metals produce oxygen containing products, like NO and N2O, at potentials where the surface becomes oxidized. Proof that Nads is indeed the species at the surface of a deactivated electrode is given in chapter 7, by identifying the chemisorbates

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Catalytic Oxidation of Ammonia to Nitrogen than alumina-supported catalysts. At high O2/NH3 ratios the activity of all catalysts increased but the selectivity for nitrogen production decreased. In all, CuY and silver-based catalysts were found to be the most promising catalysts for low temperature SCO process. In Chapter 3 various kinds of copper oxides supported on alumina and on zeolite Y have been prepared and studied in detail. TPD, TPR, UVvis spectroscopy and high-resolution electron microscopy (HREM) were used to characterize these catalysts in an attempt to shed light on the optimal preparation for active and selective low-temperature ammonia oxidation catalysts. The HREM and UV-vis measurement results showed that a CuAl2O4-like phase was more active than a CuO phase for SCO reaction. NH3 TPD profiles on Cu-Al-10 indicated that both surface oxygen and lattice oxygen can react with ammonia to produce N2. However, surface oxygen was much more active than lattice oxygen at low temperature. NH3 TPD on CuY catalysts showed three types of active centers. Two of these were active at low temperature (below 200°C) and one was active at a higher temperature (above 300°C). The existence of low temperature active centers indicated that ammonia oxidation at low temperature on copper catalysts was possible. According to the UV spectra, the [Cu-O-Cu]2+-like species or small copper oxygen aggregates were responsible to the low temperature active centers. However the amount of low temperature active centers or the concentration of [Cu-O-Cu]2+ species was small prior to NaOH treatment. The NaOH treatment of CuY increased the amount of low temperature active centers. These studies apparently indicate that the environment or the type of active copper species is very important for low temperature ammonia oxidation and is strongly related with different supports and preparation methods. In Chapter 4 ammonia oxidation reaction pathways on high surface area silver powder has been studied by TPD, TPR, FT-Raman and transent as well as steady-state ammonia oxidation experiments. Silver is a very active catalyst for ammonia oxidation. At low tempe-rature (below 300°C) mainly N2 and N2O are produced. At higher temperature NO instead of N2O becomes one of the products. NO is an important reaction intermediate for this reaction. Even at room temperature the NO can be produced and adsorbed on silver surface in the form of NOx. Since NO can not desorb at low temperature it blocks the active sites for oxygen dissociation. The dissociation of oxygen is thus believed to be the rate-controlling step for ammonia oxidation.

Promotors: Prof.dr. R.A. van Santen and Prof.dr. J.A.R. van Veen Department of chemical engineering Laboratory of Inorganic Chemistry and Catalysis

Lu Gang - 2002 - Department of chemical engineering The selective catalytic oxidation (SCO) of ammonia with oxygen to nitrogen and water recently is considered to be an efficient method to abate ammonia pollution. Previous studies show that noble metals such as Pt, Ir are very active for this reaction at low temperature but less selective. Significant amounts of nitrous oxide or nitric oxide are produced on these catalysts, especially under the condition of very high O2/NH3 ratios. Metal oxide catalysts such as Co3O4, MnO2, CuO, Fe2O3, V2O5 and MoO3 are also studied in the literature but the efficiencies are not enough at low temperature for a practical use. The research described in this thesis was aimed at the development of new, active and selective catalysts for low temperature selective ammonia oxidation to nitrogen. In Chapter 2 an elementary catalyst screening study was performed in order to find new catalytic components and composites for SCO reaction. The emphasis was on zeolite-based and alumina-supported metal or metal oxide catalysts. The activity of copper ion-exchanged zeolite Y catalysts for ammonia oxidation was shown to be comparable to that of noble-metal catalysts at low temperatures. The selectivity to nitrogen was much higher for the zeolite catalysts. Treatment of CuY with NaOH after ion exchange increased the ammonia oxidation activity. Alumina-supported silver catalysts showed very high activity for ammonia oxidation, even superior to noble metal catalysts. But the selectivity to nitrogen was comparable to other noble-metal catalysts. Co-fed steam dramatically decreased catalyst activity, especially at lower temperatures. Ion-exchanged zeolite Y catalysts were more stable

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The selectivity to N2, N2O and NO is mainly determined by surface oxygen coverage and temperature. Low surface oxygen coverage favors nitrogen formation. Adsorbed NOx, N2Ox species are actually inhibitors for ammonia oxidation but they also lower the surface oxygen coverage. Hence, the selectivity to nitrogen is improved by increasing the amount of these adsorbed species on silver surface. The pathway of ammonia oxidation on silver at low temperature is actually a two-step reaction. Ammonia was first oxidized to NO. This reaction step was very fast on silver. At moderate temperature (below 300°C) the NO could be removed either as N2O or N2 through surface SCR reaction, the second step of ammonia oxidation. At even higher temperature NO could directly desorb as one of the products. Apparently the SCR performance of the silver-based catalysts was related closely to the ammonia oxidation performance of the catalysts. Unfortunately the silver-based catalysts are not good catalysts for SCR reaction. Therefore a large amounts of N2O is produced. Generally speaking, silver alone, like Pt, is not a good catalyst for selective ammonia oxidation to nitrogen because too much N2O is produced. It follows from the above conclusions that blocking of the sites for oxygen dissociation is an effective way to improve the nitrogen selectivity, but also would result in a loss of catalyst activity. In Chapter 5 low temperature gas phase oxidation of ammonia to nitrogen has been studied over alumina-supported, silica-supported and unsupported silver catalysts to distinguish the support effect on silver-based catalysts. TPD, TPR, TEM, XRD and FT-Raman were used to characterize the different silver catalysts. The results showed aluminasupported silver to be the best catalyst due to the interaction of silver with alumina. Pretreatment had a great affect on the catalyst performance. Reduction in hydrogen at 200°C without any pre-calcination gave the best activity while reduction at higher temperatures showed ittle difference from calcination pretreatment. At least four types of oxygen species were produced when silver was oxidized at high temperature. These species are adsorbed molecular oxygen, adsorbed atomic oxygen, subsurface oxygen and bulk dissolved oxygen respectively. Ammonia oxidation activity at low temperature is related to the catalyst.s ability of dissociatively or non-dissociatively adsorption of oxygen. In addition, a good correlation existed between the N2 selectivity for SCO reaction and the SCR performance of NO with NH3 for the silver-based catalysts, i.e., the higher SCR yield of nitrogen,

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the higher the SCO N2 selectivity. In Chapter 6 a new bi-functional Cu-Ag/Al2O3 catalyst was developed based on the previous reaction mechanism study, which showed not only high activity but also high selectivity for ammonia oxidation. The catalysts have been characterized by XRD, XPS, LEIS, TEM and EDX. In all catalysts analyzed by LEIS and TEM, copper has a very high dispersion. Most likely, the catalysts contain copper oxides platelets with a thickness of roughly 1 monolayer. At increasing copper loading, relatively more (or more extended) rather than thicker platelets are formed. However, silver has a broad particle size distribution. The average size of the Ag species ranges between 2.5 and 5.5 nm measured from LEIS. These numbers increase with increasing silver loading. The XRD and XPS results show that the valence states of copper and silver are the same for single component catalysts and bi-component catalysts. The TEM images and LEIS measurements also show no big difference in the particle size distribution for all these catalysts. There is no indication for the formation of a new Cu-Ag phase or the formation of Cu-Ag alloy. So the remarkable change for selectivity with addition of copper is not due to the synergic effect between copper and silver, or the particle size effect. The EDX results show that copper and silver exist together anywhere on the alumina surface. This proves that there is an intimate contact between copper and silver on alumina-supported Cu-Ag catalysts. The promotion effect of copper can thus be well explained by a mechanism of bi- functional catalyst, in which the silver component mainly catalyzes ammonia oxidation to NO, the first step of this reaction, and the copper catalyzes NO SCR reaction to nitrogen, the second step of ammonia oxidation on silver. Multi-functional catalysis is not a new concept, but catalyst design deliberately based on the principle of multifunctionality will be inevitable to develop high-performance catalysts which can cope with such difficult problems as in ammonia oxidation. This study only gives one example of such a design. Actually there are more alternatives available. Besides silver, many noble metals such as Pt, Ir are very active for ammonia oxidation with low selectivity to nitrogen due to the less efficiency for SCR reaction. There are also many good SCR catalysts such as vanadium oxide, iron oxide. Opportunities still exist for preparing high-performance bi-functional catalysts from these catalytic components.

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On the formation and reactivity of multinuclear silsesquioxane metal complexes The second chapter describes the reactivity of silsesquioxane trisilanol ligands with Grignard and dialkyl magnesium reagents. Reaction of Grignard reagents with trisilanol ligands leads to the formation of a new tetranuclear di-silsesquioxane structure. The formation of this new material is investigated by the use of model reactions that represent phases in the synthesis steps of the complex. It was found that these model reactions fit well to the proposed three-step model. The apparent electron-withdrawing character of the silsesquioxide ligand was noticed in the very short length of the magnesium-chloride bond, and was confirmed by DFT computations. The strength of the magnesium chloride bond was also of influence in the study of the reactivity of the complexes towards protic and metallated substances like alcohols, alkoxides and amides. No reaction could be determined. Only the use of silver triflate resulted in the formation of silver chloride and a degradated silsesquioxane framework. Activation of the silicon-oxygen-magnesium bond proved to be easier, and could be used to prepare silsesquioxane complexes with other metals than magnesium.

Promotors: Prof.dr. R.A. van Santen and Prof.dr. D. Vogt Copromotor: Dr. H.C.L. Abbenhuis Department of Chemical engineering, Laboratory of Inorganic Chemistry and Catalysis

Rob Hanssen - 2003 - Department of Chemical engineering Silsesquioxane chemistry has taken a tremendous flight over the past decade. New synthetic approaches were developed; new complexes based on elements throughout the periodic table were synthesized, and were applied in catalytic processes such as alkene epoxidation, Oppenauer oxidation, alkene polymerization, Diels-Alders reactions and alkene metathesis. The use of silsesquioxane ligands as models for silica surface disclosed intimate knowledge of the reactions on the surface of this much-used support. New methods were developed to incorporate silsesquioxanes into new materials. Encapsulation in siloxane polymers providedprecision supports for catalysts and controlled calcination produced materials with welldefined metal oxide particles.

Chapter three deals with the investigation of the interaction of silsesquioxane trisilanol ligands with alkyl zinc precursors. Reaction of these ligands with dialkyl zinc reagents in non-coordinating solvents yielded planar three-coordinate silsesquioxide zinc alkyl complexes with the same tetranuclear motif as found in the second chapter. The formation of this type of complexes was independent of the silsesquioxane side group, contrary to the magnesium type compounds. The polar character of the carbon-zinc moiety and the low coordination of zinc atoms made the complexes very reactive towards coordinating and polar substances. Addition of methyl zinc chloride, a zinc congener of a Grignard reagent, to a solution of trisilanol in THF formed the zinc alternative to the magnesium complexes in the second chapter. The zinc complexes were tested in the polymerization of lactide and were found to be active for a very short time before they precipitated from solution.

A detailed knowledge of the synthetic part towards catalytically active complexes is needed in order to make the appropriate complexes. This thesis is concerned with the interaction of main group and transition metal precursors with silsesquioxane trisilanol ligands in order to study the coordination chemistry and to synthesize new catalysts based on silsesquioxane ligands. In the first chapter, concepts and literature of silsesquioxane ligands and their metal complexes are reviewed. The main conclusions from the literature to date (February 2003) are (i) that silsesquioxane are the best available models for silica surfaces, (ii) that the ligands can be used to bind to a large variety of metals, be it main group, early or late transition metals, and (iii) that the application of silsesquioxane metal complexes in catalysis is not yet widespread, but promising in some areas.

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In the fourth chapter, the knowledge of formation mechanisms gained in the previous two chapters was applied to the synthesis of heterobimetallic compounds. The formation of heterobimetallic silsesquioxane complexes proved to be dependent on the oxophilicity of both metal compounds. Oxophilic (‘hard’) metals could easily replace softer metals to gain a more oxygen-rich environment. In case of zinc/magnesium,

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Positron Emission Profiling Study of Ammonia Oxidation on Platinum this led to exchange of the metal sites; in the case of aluminum and titanium, it led to complete expulsion of the softer metal. A mixed-metal magnesium-vanadium complex was tested in the catalytic polymerization of ethene and found to be reasonably active in producing highmolecular weight polyethene. However, it was found to be sensitive toward metal leaching depending on the temperature and aluminum activor. Based on the successful application of vanadium silsesquioxane chemistry polymerization of ethene in the previous chapter, chapter five is involved with trivalent vanadium and titanium complexes of silylsubstituted silsesquioxane disilanol ligands. The coordination behavior of solvents like THF and pyridine is studied with UV-Vis and qualitatively confirmed by DFT computations. The position of the UV-Vis absorption bands and the relative stability of adducts match well with the computational results. Polymerization of ethene to high molecular weight polyethene was possible with both vanadium and titanium complexes, although the activity of the titanium catalyst was very low. Under the conditions studied, the vanadium catalysts were very active, but only for a few minutes A possible way of selfimmobilizing catalysts by incorporating polymerizable groups in the ligand was proposed and tested, but the current systems could not be used with this approach. A tentative catalytic cycle was described and supported by DFT computations. The energetics of the reactions were found to be significantly lower than literature values, possibly explaining the low stability of the catalyst at reaction conditions.

Promotors: Prof.dr. R.A. van Santen and Prof.dr. M.J.A. de Voigt Copromotor: Dr.ir. A.M. de Jong Department of Chemical engineering, Inorganic Chemistry and Catalysis Schuit Institute of Catalysis, Heterogeneous catalysis group

Dariusz Sobczyk - 2003 - Department of Chemical engineering The main objective of this research is to study the mechanism of the catalytic ammonia oxidation on platinum at low temperatures, atmospheric pressure and plug flow conditions. A short literature review on the ammonia oxidation over platinum catalysts is given in chapter one. The need for purification of ammonia slip streams from industrial processes, like the selective catalytic reduction and soda process, was an impulse to start efforts to convert ammonia into harmless products. Emissions of ammonia are well known sources of pollution of soil, water and air. Platinum based catalysts are promising in the conversion of gaseous ammonia to harmless N2 and H2O at relatively low temperatures. They have a high activity and selectivity for N2 formation, however, the most important drawback of platinum based catalysts is their fast deactivation, which is discussed in chapters five and six. A suitable technique to study in situ transient and steady state phenomena is Positron Emission Profiling (PEP), which is applied in this study. In chapter one the background and the major applications of this technique are described.

General conclusions A new family of complexes, based on a general motif of four metal atoms in a µ3-oxygen surrounding has been synthesized and the reactivity was tested. Depending on the ligands on the outer (reactive) metal atoms, the reactivity ranges from very reactive towards protic and coordinating substances to completely unreactive. Based on the reaction mechanism, new heterobimetallic complexes could be synthesized, although caution should be taken regarding the ‘hardness’ of the metals. Selected complexes were tested in various catalytic reactions and were found to be inactive (Diels-Alder), active but unsuitable (lactide polymerization), or very active (ethene polymerization). Integrating the synthetic knowledge from this thesis into the relevant new developments in silsesquioxane chemistry could lead to the introduction of new and active catalysts for Lewis-acid based catalysis.

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To apply PEP in this catalytic study, first production methods for positron-emitterlabelled [13N]NH3 and [15O]O2 are developed (chapter two and three). The aim was realised, to produce gaseous [13N]NH3 and [15O]O2, which can be injected in small quantities into the reaction flow. These [13N]NH3 and [15O]O2 pulses have a high chemical and radionuclidic purity and sufficient specific radioactivity to be applied in the PEP studies. The production of these radioactive pulses is reproducible,

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fast, simple to operate and can be repeated batchwise, the [13N]NH3 pulses every 20 minutes and the [15O]O2 pulses every 2 minutes. 13N is formed via the irradiation of water with 16 MeV protons (500 nA). To facilitate smooth evolution of gaseous [13N]NH3 from the irradiated water, the DeVarda’s alloy method was adjusted. Pre-treatment of DeVarda’s alloy with water improved the manageability and reproducibility of the [13N]NH3 pulses and also the concentration of the labelled ammonia in the pulses. The method prevents adequately contamination from other radionuclides formed, in particular 18F. Chemical purity is achieved by a simple GC purification step, easily separating ammonia from air, hydrogen and water. The [15O]O2 pulses have been produced using the 14N(d,n)15O and 16O(p,pn)15O reaction. Both methods are based on the irradiation of a gaseous target, nitrogen or oxygen. The radiolabelled by-products of the irradiations are short living isotopes: 13 N, 17F and 18F (16O(p,pn)15O method) and 13N, 16N and 11C (14N(d,n)15O method). Chemical and radionuclidic purity is achieved by application of charcoal and sodalime absorbers and oxygen separation in a Molsieve column. The 14N(d,n)15O method produces carrier-free [15O]O2 pulses with a relatively higher specific activity. The specific activity of the 16O(p,pn)15O production method is much lower due to 16O-oxygen carrier gas.

and also NO is formed. The TPD and TPO experiments together with the reaction experiments with hydrogen, ammonia and nitric oxide indicated that a part of [13N]NH3, which remained at the surface, was mainly NHx. The ammonia oxidation experiments showed the fast deactivation of the platinum sponge catalyst below 400 K (chapter 5). The XPS and temperature programmed experiments showed that NH2(a) and NH(a) are poisoning the catalyst. The main reason for the deactivation of the platinum catalyst is the fact that the NHx(a) + OH(a) reaction is much slower than formation of water via hydroxyls. In this way the NHx species (NH and NH2) remain unreactive at the surface and they block the active sites. The oxygen species do not poison the catalyst, unless oxygen is pre-adsorbed at platinum. The pre-oxidised platinum sponge deactivates faster than the platinum sponge due to surface poisoning caused partly by the nitrogen species and partly by unreactive oxygen. The nitrogen formation proceeds via the recombination of atomic nitrogen and not via the NO(a) intermediate. Low surface coverage does not favour the NO(a) formation and below 400 K the dissociation of NO is prohibited. The intermediate NO(a) seems to be mainly involved in the formation of N2O, which occurs at high surface coverage, when the catalyst deactivates. Above 400 K nitrogen and water are formed and the catalyst maintains its high initial activity. The NO pulse experiments indicate that small quantities of NO can be selectively converted to nitrogen. Also N2O decomposes to nitrogen, which explains the high selectivity towards nitrogen. However, the reaction route for the nitrogen formation, above 400 K, is still unclear.

Chapter four elaborates on the first elementary steps in the low temperature ammonia oxidation, adsorption of ammonia and oxygen on platinum. The PEP experiments have shown that dissociation of ammonia on platinum is not favourable and that the interaction of ammonia with platinum is weak. Oxygen strongly adsorbs on platinum and immediately dissociates. This study, performed at atmospheric pressure conditions over pure platinum sponge, confirms UHV and theoretical studies by showing that ammonia dissociation on platinum is activated by the presence of oxygen at the surface.

Ammonia oxidation over Pt/γ-alumina catalyst showed similar features compared to the platinum sponge. Below 400 K Pt/γ-alumina showed almost no catalytic activity. The pretreatment of Pt/γ-alumina with oxygen lowers initial TOF, the adsorbed oxygen accelerates deactivation of the catalyst. During the ammonia oxidation the NHx(a) species remain adsorbed at the platinum sites and thus they also deactivate the catalyst. The use of the γ-alumina support has the disadvantage that ammonia strongly adsorbs on alumina. This means that while the am-monia saturates the alumina sites, oxygen adsorbs on (deactivates) the platinum sites and the initial reaction proceeds in an oxygen-rich environment. The oxygen spillover to the alumina is insignificant.

Adsorption of NH3 on Ptreduced ->weak molecular adsorption Adsorption of NH3 on Pt-O ->strong dissociative adsorption The PEP experiments have elegantly shown that platinum pre-covered with oxygen initiates the ammonia dissociation partly leading to the gaseous products. Below 423 K mainly nitrogen and a small amount of N2O is formed and above 423 K the product selectivity is changed

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Composites based on natural fibres and thermoplastic matrices Above 400 K Pt/γ-alumina showed much higher initial activity. However, below 520 K the catalyst still deactivates. In this temperature region (400 - 520 K) mainly the oxide formation causes the deactivation of the catalyst. The oxide formation takes place during the reaction, as the pre-oxidised catalyst showed similar catalytic behaviour. Above 520 K the catalyst is stable and active. In chapter seven, the strong interaction of ammonia with γ-alumina is studied. In accordance with the literature, it is shown with infrared and TPD experiments that ammonia chemisorbs on two Lewis acid sites of γ-alumina. Radiolabelled experiments, which involved the 13NH3/14NH3 exchange reaction on γ-alumina, showed that adsorption assisted desorption of chemisorbed ammonia takes place. Physisorbed ammonia strongly affects the desorption of chemisorbed ammonia and Hads of chemisorbed ammonia on γ-alumina is lowered. The PEP technique allowed us to measure in situ the heat of adsorption of ammonia on γ-alumina during the ammonia equilibrium. The overall isobaric heat of adsorption is calculated to be -11 kJ/mol ± 1 kJ/mol in the temperature range of 323 - 473 K.

Copromotor: Dr.ing. A.A.M.J. Peijs Department of Chemical Engineering

Sanjeev Garkhail - 2001 - Department of Chemical Engineering The above mentioned project was started to utilise natural fibres such as flax, jute etc. as reinforcement for composites based on plastic matrices. Some of the advantages offered by natural fibres are: a They are cheap, renewable, non-abrasive to processing equipment, b Natural fibres are light in weight which is advantageous for light weight composite applications (e.g. automotive parts, extruded fibre reinforced panels and railings for applications such as panels and composite terrace) and have good mechanical properties c Natural fibres can be CO2 neutral i.e. carbon-dioxide utilised during growth is equivalent to carbon-dioxide evolved on disposal d Natural fibres are bio-degradable which can be a positive factor for disposal and a negative factor when long term durability is concerned e Natural fibres give less concern with safety and health during handling of fibre products f Natural fibres can be incinerated for energy recovery Flax fibres were selected as reinforcement mainly because of their good mechanical properties when compared with other natural fibres and also because of their availability in different forms in Western Europe. Different types of flax fibres were used i.e. Green flax, dew-retted flax and ‘DuralinTM’ flax in various forms i.e. chopped fibres, non-woven mats and long (continuous) fibre strands. Also, different types of plastic matrices were used i.e. polypropylene (PP), poly-3-hydroxybutyrate (PHB) and poly-3-hydroxybutyrate-co-3-hydroxyvalerate (PHBV) copolymer, for

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manufacturing composites with flax fibres. Various routes were used to manufacture the composites such as compression moulding (film stacking and blend mats) and injection moulding. The effect of the above mentioned parameters on the composite properties (like dimensional stability and mechanical properties) was studied. Attempts were made to enhance the interfacial adhesion between fibre and matrix through fibre surface modifications as well as matrix modifications (blending). The project on the whole can be sub-divided into following major parts:

stability and can be processed up to around 200-220°C, which limits the applicability of these fibres. Based on the thermal stability as well as commercial aspect of composite, polypropylene (PP) was selected as the principal matrix material for this study. One of the crucial factors affecting the property of a composite is the bonding between fibre and matrix. The fibre/matrix bond not only affects the mechanical properties but also environmental properties like moisture pick-up. Several methods were used and studied to improve fibre/matrix bonding. Both, chemical treatment of fibre and matrix, as well as physical modification i.e. developing specific matrix morphologies (transcrystallinity) through controlled processing conditions were used to enhance the interaction between flax fibre and PP matrix.

a Optimisation of the mechanical properties of flax/PP thermoplastic composites made through compression moulding (film stacking and paper-making methods) and injection moulding. b Optimisation of the environmental properties (moisture uptake and dimensional stability) of the developed composites using upgraded flax fibres (DuralinTM). c Development of completely biodegradable thermoplastic composites, based on flax fibres and (PHB) Poly-3-hydroxybutyrate and (PHBV) Poly-3-hydroxybutyrate-3-hydroxyvalerate copolymer matrix material. d An attempt to optimise the macro-mechanical properties of flax/PP and flax/PHB(V) composites through micro-mechanical study (involving micro-debonding and fibre pull-out tests). e Life Cycle Analysis of natural fibre reinforced composites and glass fibre reinforced composites. For that purpose computer program SimaPro (developed by Pré consultants, the Netherlands) was used.

One of the major advantages of using natural fibre reinforced thermoplastic is based on the assumption that these composites would be environment friendly as far as processing and disposal of the materials was concerned. A life cycle assessment (LCA) study was conducted on flax fibre reinforced PP composites and compared with GMT composites based on PP matrix. From the study it can be concluded that, for nonautomotive applications as well as strength and impact critical automotive applications, PP and flax based NMTs are less environment friendly when compared with PP based GMT materials. Some of the factors contributing to the less environment friendly character of NMTs are the use of chemicals like fungicides, pesticides, herbicides and fertilisers during growth of flax fibres and higher weight of composite needed to satisfy tensile and impact properties criteria for automotive applications. Higher weight of NMTs when compared to GMTs would lead to higher fuel consumption. Due to weight saving, NMT composites for ‘stiffness critical’ automotive applications showed better environmental performance when compared to GMT composites. However, there are certain disadvantages of LCA studies as some of the factors were not included such as the negative effect of using glass fibres on human health and maintenance of processing machines, which would be higher due to abrasive wear by glass fibres. Also if possible one can use natural fibres which are grown easily without help of chemicals such as fungicides, pesticides, herbicides and fertilizers.

From the present study it can be concluded that flax fibre is a good candidate for reinforcing thermoplastics because of its good mechanical properties. Also, because of its highly crystalline and oriented molecular morphology flax fibre exhibit anisotropic mechanical properties and they are very sensitive to compressive loading. The final properties of flax fibre depend on the processing and can be engineered through different processing methods. One of the examples of improved performance of flax fibre through processing is Duralin flax, which has lower moisture sensitivity along with improved mechanical properties. In addition, Duralin fibres have improved thermal stability. The use of Duralin fibres also resulted into a reduced amount of scatter in the composite mechanical properties when compared to composites based on e.g. dew-retted fibres. Flax fibres in general have low thermal

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Scale-up of the Juliá-Colonna epoxidation scale and for the OLL-synthesis efforts are being made to reduce the polydispersity to increase the efficiency of the catalyst. After scale-up of the OLL-synthesis to 1 dm3 scale as well, the epoxidation itself will be addressed again. The focus will shift from a chemical view towards the fine chemical process engineering aspects in process design. Process design of the conceived system on 1 dm3 and 10 dm3 miniplant scale should give information on further scale-up of the process to industrial scale.

Promotor: Prof. dr. B. Hulshof Copromotors: Dr. J. Meuldijk and Dr. J. Vekemans Department of Chemical Engineering, Applied Organic Chemistry

References 1

Paul van der Weide - lopend - Department of Chemical Engineering

Juliá, S.; Guixer, J.; Masana, J.; Rocas, J.; Colonna, S.; Annuziata, R.; Molinari, H. J. Chem. Soc. Perkin Trans. I 1982, 1317

Chiral epoxides are important building blocks in the pharmaceutical, agrochemical, flavour and fragrance industry due to their reactivity. At the moment asymmetric syntheses of epoxides involve the use of transition metal complexes. Additionally, chemical transformations leading to epoxidations are accompanied by the formation of substantial quantities of waste. This project aims at developing a sustainable, competitive alternative for today’s electron deficient enone epoxidation processes. Synzymes (e.g. oligo-L-amino acids, OLL’s) have been applie in the Juliá-Colonna (JC) epoxidation, as reported1 with promising results.

2

Porter, M.J.; Skidmore, J. J. Chem. Soc. Chem. Commun. 2000, 1215

3

Bentley, P.A.; Flood, R.W.; Roberts, R.M.; Skidmore, J.; Smith, C.B.; Smith, J.A. Chem. Commun. 2001, 1616

4

Berkessel, A.; Gasch, N.; Glaubitz, K.; Koch, C. Org. Lett. 2001, 3839

Improvements and modifications to this three phase system have been reported since.2 The mechanism of the JC epoxidation is yet unknown. The reaction has been found to take place at the N-terminus of the oligopeptide and involves the action of the last three amino acids for stereo selectivity.3 Studies on the effect of chain length of OLL on the catalytic performance in the three phase system indicate the involvement of the stability of the α-helix in the reaction, as activity increases with increasing length, leveling off at around 14 units.3 Using an experimental design, the critical parameters in the state of the art JC epoxidation were determined. The most critical parameter appeared to be the catalyst. Therefore efforts have been made to improve the catalyst synthesis. Enhancing the purity of the activated monomer of leucine, N-carboxyanhydride (Leu-NCA), led to improved and reproducible catalysts. At the moment the Leu-NCA synthesis is being scaled up to 1 dm3

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Rare earth activated – (oxy) nitride materials Relationship between the emission maxima and the unit cell volume, Stokes shift and the bond length of Eu-N. With respect to the activator ions, the Eu2+ ions strongly depend on its local coordination, the doping concentration as well as the framework of the host lattices, such as SiN4, (Si, Al)-(N, O)4. Therefore, by tuning the chemical composition or varying the local structure can significantly improve the emission characteristics of the alkaline earth silicon nitride materials. However, Ce3+ and Tb3+ ions in most of (oxy) nitride hosts are insusceptible to their surroundings. The position of emission band or peak is hardly to modify.

Promotor: Prof.dr. G. de With Copromotor: Dr. H.T. Hintzen Department of Chemical Engineering

Yuan Li - lopend - Department of Chemical Engineering

New rare-earth doped (oxy) nitride host still need to explore. The crystal structure of some new (oxy) nitride compounds will be determined in order to build up the relationship between the structure and optical properties.

The development of new (oxy) nitride compounds for luminescent materials has been increased during the past few years. Oxynitride materials show some unique characteristics as host lattices compared with oxide, sulphide and halide. The invention of rare earth activated (oxy) nitrides with high efficiency, strong absorption and high stability is a great challenge. The present investigation is focused on exploring new (oxy) nitride compounds and correlating the structure with the luminescence properties of rare earth doped materials.

Literature 1

H.T. Hintzen, Y.Q. Li, Encyclopedia of Materials, 2004.

2

Y.Q. Li, H.T. Hintzen, G. de With, J. Alloy and Comp., 2004

3

Y.Q. Li, H.T. Hintzen, G. de With, J. Soli State Chem., submitted.

4

H.T. Hintzen, Y.Q.Li, et al, PCT Int. Appl., WO 2004030109.

In the past years, we have studied some novel (oxy) nitride materials with different structures and varying compositions. The structure and optical properties of rare earth (like Eu2+, Ce3+ and Tb3+) activated (oxy) nitride phosphors have been investigated by X-ray powder diffraction and fluorescent spectroscopic analysis. Some new (oxy) nitride compounds were synthesized by high temperature solid-state reaction method. The crystal structures were refined by the Rietveld method and the luminescence properties of rare earth doped materials were characterized. Several phosphors based on silicon-alumina oxynitrides with high absorption of UV/blue radiation and high efficiency have shown very promising applications in lightemitting diodes (LEDs). Emission spectra of Sr1-x Eu xSi4N7 as function of doped - Eu2+ concentration (λexc = 390 nm).

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Transities Dr.ir. Geert Verbong Faculteit Technologie Management

Uit een samenwerking van de faculteit Natuurkunde (sectie Systems and Control) en de faculteit Technologie Management (sectie Environment and Energy) zijn een tweetal proefschriften voortgekomen, beide gestimuleerd door Technologie voor Duurzame Ontwikkeling (TDO). Het gaat hierbij om een proefschrift over duurzame produktie en een proefschrift over een duurzaamheidsanalyse van de verschillende huishoudelijke watersystemen. Een belangrijke manier om duurzame productie te behalen is het sluiten van materiaalketens, omdat recycling van afgedankte producten en procesafval een effectieve methode is om het storten van afval te verminderen en de uitputting van grondstoffen te vertragen. Dr.ir. Uwe Kleineidam introduceert in zijn proefschrift een methode voor het modelleren en regelen van product-proces ketens die voor overheden en het bedrijfsleven van belang is. Ter illustratie van de modellerings- en analysetechnieken wordt de Nederlandse papierketen onderzocht. In de modelanalyse wordt eerst de stabiliteit van de papierketen aangetoond. Stabiliteit houdt in dat de productstromen en de prijzen niet onbegrensd groeien. Ten tweede wordt de regelbaarheid van de keten geanalyseerd. De papierketen is een voorbeeld van een bestaande keten waarin al geruime tijd recycling wordt toegepast. Daarom is zij geschikt voor het toetsen van de in dit proefschrift beschreven modellerings- en analysetechnieken. De uitgevoerde case study toont de bruikbaarheid van deze technieken voor de analyse en regeling van productketens aan.

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of the Master’s track 'Technology and Society' were able to do their Master’s project

Dr.ir. G.P.J. Verbong, Department of Technology Management

within the project on the water systems. Neither one of the PhD studies has lead to new

Cooperation between the Department of Applied Physics (Systems and Control Group)

projects in those areas yet. Verbong considers the research of sustainable production to

and Department of Technology Management (Environment and Energy Group) led to

be a niche in the research in their group at the moment.

two thesesthat were both financed by the TU/e incentive arrangement for sustainable

Opportunities for new research mostly lie in the area of Industrial Ecology en Reverse

development (techniek voor duurzame ontwikkeling (TDO)). One thesis deals with

Logistics. Transition research is now the main path in the research. This research is

sustainable production (by Dr.ir. Uwe Kleineidam) and the other thesis discusses a

focused on the analysis and understanding of long-term processes of change in socio-

sustainability analyses of several water systems for households (by Dr.ir. Annelies van

technical systems, like the electricity supply. The transition to a more sustainable energy

der Vleuten-Balkema).

supply is not so much a technical problem – there are a lot technical opportunities to do

Dr.ir. Geert Verbong is assistant professor in the History, Philosophy and Technology

so - but mainly a social problem.

Studies Group at the Department of Technology Management. He is head of the

According to Verbong, the fact that the group only has two PhD students that are

Technology and Sustainability Studies Group. According to Verbong, several students

financed by TDO is all a matter of timing. At the time the money of the TDO incentives

Het tweede proefschrift gaat over huishoudelijke watersystemen. De schatting van de Wereld Gezondheidsorganisatie is dat anno 2003 ongeveer 18% van de wereldbevolking geen toegang heeft tot veilig drinkwater en dat ongeveer 40% niet is voorzien van hygiënische sanitatie. Om inzicht te krijgen in de duurzaamheid van de verschillende huishoudelijke watersystemen, heeft Dr.ir. Annelies van der Vleuten-Balkema een duurzaamheidanalyse ontwikkeld die is samengesteld uit bestaande methoden als kostenbatenanalyse, levenscyclusanalyse, en sociale analyses. De belangrijkste kenmerken die deze analyse als geheel meerwaarde geven zijn: de brede visie, de set van indicatoren, de ontwerpgerichte methode van modelleren die is gebaseerd op een superstructuur en de multiobjective optimalisatie. Deze duurzaamheidanalyse is geïmplementeerd in een beslissingsondersteunend computermodel voor de selectie van duurzame huishoudelijke watersystemen.

kunnen doen. De beide onderzoeken hebben nog niet tot nieuwe vervolgonderzoeken geleid. Verbong ziet het onderzoek over duurzame productie ook min of meer als een niche in het huidige onderzoek in hun groep; mogelijkheden voor nieuw onderzoek liggen vooral op het gebied van Industriële Ecologie en Reverse Logistics. Het transitie-onderzoek vormt nu de hoofdlijn in het onderzoek. Dit onderzoek richt zich met name op de analyse en verklaring van lange termijn veranderingsprocessen in technisch-maatschappelijke systemen, zoals de elektriciteitsvoorziening. De transitie naar een meer duurzame energievoorziening is niet zozeer een technisch probleem - er zijn namelijk veel technische mogelijkheden om dat te realiseren - maar vooral een maatschappelijk probleem. Dat de vakgroep niet meer TDO-AIO’s heeft gehad, is volgens Verbong een kwestie van timing. Op het moment van verdeling van de TDO stimuleringsgelden was er minder noodzaak tot financiering voor het reeds lopende onderzoek. Via andere wegen zoals NWO-NOVEM werd het onderzoek gefinancierd. Wel heeft TDO, en met name Dr.ir. Lex Lemmens, een cruciale rol gespeeld in het bemiddelen bij geld van de provincie. De provincie Noord-Brabant, en ook energiebedrijf Essent, stimuleren namelijk de AIO Ir. Rob Raven deels. TDO stimuleert in dit geval dan misschien niet direct, maar toch

Dr.ir. Geert Verbong is universitair hoofddocent bij de capaciteitsgroep Algemene Wetenschappen van de faculteit Technologie Management. Hij leidt de sectie Techniek en Duurzaamheidsstudies. Hij vertelt dat het laatste project, over de watersystemen, verschillende studenten van de studie Techniek en Maatschappij de mogelijkheid heeft geboden hun afstudeeronderzoek binnen dit project te

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Modelling and Control of Product Life-Cycles was divided, the need for financial support was not very urgent in the group.

Promotors: Prof.dr. R.J.J. van Heijningen and

The research was supported by NWO-NOVEM for example. However, TDO and especially

Prof.dr.ir. J.J. Kok

Dr.ir. Lex Lemmens, played a crucial mediating role in acquiring money from the

Copromotor: Dr.ir. A.J.D. Lambert

province of North Brabant. The province as well as energy company Essent are now supporting part of the work by the PhD student Ir. Rob Raven. So though TDO is not

Department of Technology Management,

directly supporting this research, indirectly it has.

The energy and environment group

Verbong is a member of the joint committee of TDO. He judged proposals, for example,

Department of Applied Physics,

and knows TDO very well. Besides all this, Verbong mentions the biomass working

Systems and control group

group at the TU/e. This group consists of researchers from several departments who work on subjects concerning biomass. TDO is the driving force behind this group. According to Verbong this group is a productive initiative to stimulate the cooperation between researchers at the TU/e.

Uwe Kleineidam - 2000 - Department of Technology Management

op een indirecte manier een beetje het onderzoek.

In the last decades governments as well as industry have taken measures to achieve sustainability. One major opportunity for sustainable production is the reuse of waste streams, because recycling of discarded products is an effective way of diminishing the discharge of wastes and decreasing the depletion of resources. Since measures taken to influence the recycling of a product have effects on the production and consumption processes linked to the product, entire chains of such production and consumption processes are considered. A productprocess chain describes such a complete chain in a standard way. Productprocess chains are used in the framework of industrial metabolism to map the flow of materials and products through the industrial system by applying the laws of mass and energy conservation. In this study, the whole life-cycle of products is examined, from the initial extraction of raw materials to the reintegration, at some point, of their wastes into the ecosystem. Chains are influenced by the decisions of producers and consumers regarding product flows. These flows can be altered by the substitution of materials and products, the recycling of materials and the reuse of products. Governmental measures are external in.uences: regulatory influences, for example by the prescription of maximum emission levels, economic influences, for example by taxes and subsidies, and social influences, for example by the stimulation of environmental research and the stimulation of self-regulation of the chains. This study presents a method for modelling and controlling productprocess chains, which is of interest for governmental authorities as

Verbong is lid van de gemeenschappelijke commissie van TDO. Hij heeft onder andere onderzoeksvoorstellen meebeoordeeld en dus van binnenuit meegedraaid bij het doen en laten van de gemeenschappelijke commissie van TDO. Daarnaast haalt Verbong ook de ‘biomassa-werkgroep’ aan. Deze werkgroep bestaat uit onderzoekers van verschillende faculteiten die werken aan onderwerpen die te maken hebben met biomassa. TDO is hiervan de trekker. Verbong ziet deze werkgroep als een vruchtbaar initiatief om de samenwerking tussen onderzoekers op de TU/e te bevorderen.

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well as for industry. The chain models consist of elementary company models, which are connected by market models. Dynamic processes, such as market and storage processes, are included. By combining the company and market models, a large variety of product chains can be modelled, with the option to include recycle loops. Companies are conceived as consisting of resource and product inventories and of a transformation process. By applying the law of mass conservation to these inventories, two coupled dynamic equations that describe a company are obtained. Production decisions and decisions on supply and demand of products are substituted into these equations. The decisions are based on marketprices. The price developments determined by the difference between demand and supply. The contribution of control theory to chain analysis and chain control is demonstrated. The chain model can be put into the standard state space description used in control theory, thereby making it possible to use various methods for system analysis and control that are available in control theory, such as stability, controllability and observability analysis. These properties are prerequisites for effective chain management, such as in the evaluation of recycling policy. To illustrate the modelling and analysis techniques, the Dutch paper chain is examined. This chain is chosen because quite extensive historical data of prices, imports to and exports from the chain have been documented. It consists of paper producers, paper consumers and waste-paper recyclers, as well as of a pulp market, a paper market, and a waste-paper market. The historical prices are in good agreement with those calculated by the model provided that the imports and exports have the observed values. In the model analysis, the stability of the paper chain is demonstrated first. Stability means that the product flows and prices in the chain do not grow unboundedly. Second, the controllability of the chain is analysed. The measures expected to influence the chain are examined to see whether they are indeed able to guide the chain in the desired way. Controllability is shown with respect to taxes and subsidies on products, taxes and subsidies on activities, the regulation of imports and exports, and an adjustment of the price for final treatment. Moreover, it is demonstrated that the chain is observable by the measurement of the product flows, the product prices or the recycling rate. This indicates that these quantities contain enough information for effective chain regulation.

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Some examples of regulations of the paper chain are modelled to show the value of the model for evaluating influences on the chain. The regulation of the paper flow by a tax on pulp illustrates a measure that leads to the attainment of the control objective. The regulation of the recycling rate by an increase of recycling activities is modelled as a second example. It turns out that this is an ineffective measure. Furthermore, it is shown that the recycling rate can be controlled by adjusting the price for final treatment. This recycling rate can also be controlled through a combination of the final treatment price with a subsidy for waste-paper, which is a politically attractive regulation. Finally two measures aimed at reducing price fluctuations are modelled: a waste-paper subsidy and some kind of self-regulation, which has recently been introduced in the paper chain. This so-called paper fibre convenant provides mutual sale and purchase agreements aimed at a more secure throughput of paper through the chain and an increase of household waste-paper collection. It is demonstrated that the two influences can indeed improve the chain behaviour. The paper chain is an example of an existing chain in which recycling has been applied for a long time. Therefore it serves the purpose of examining the modelling and analysis techniques described in this thesis. The case study demonstrates the usefulness of these techniques for the analysis and control of productchains.

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Sustainable wastewater treatment: developing a methodology and selecting promising systems indicators, the process design oriented approach for modelling through the use of a superstructure, and selection of optimal structures by multi-objective integer optimisation. We implemented this sustainability assessment in a model-based decision support tool for the selection of sustainable domestic water systems. The three main components of this tool are:

Promotoren: Prof.dr.dipl-ing. H.A. Presig and Prof.dr.ing. Otterpohl Co-promotor: Dr.ir. A.J.D. Lambert Department of Technology Management, The energy and environment group Department of Applied Physics, Systems and control group

1 Sustainability indicators

Based on the different dimensions of sustainability we defined a set of indicators including economic, environmental, and social-cultural aspects. In addition we included functional indicators that are used to account for characteristics of technologies such as robustness, adaptability, and maintenance. The total set consists of 27 sustainability indicators, some of these are quantified in the mass balance for instance rainwater use, some others are derived indirectly through a categorisation of the outgoing streams, for instance water with a quality suitable for domestic reuse. A third type of indicators provides a qualitative measure, for instance social acceptance and robustness. These are used to indicate a potential advantage or disadvantage of a certain technology.

Annelies van der Vleuten - 2003 - Department of Technology Management A concrete challenge for this new millennium is to meet the UN target that aims at providing safe drinking water and hygienic sanitation to all people on earth by the year 2025. There is a wide variety of technologies that could fulfill these services, however many of the existing water systems do not provide an integral solution, such that we now face problems like eutrophication, heavy metals in sludge, water shortages. Even more complex problems are emerging, such as the loss of fertility due to traces of medicine and chemicals in the water, and scarcity of nutrients for food production due to the disruption of the nitrogen and phosphorus cycle. How can we try to meet those challenges? A major aspect in finding solutions maybe the fact that problems have become so complex that there is no single optimal solution. Furthermore, the solutions must be formulated with a long-term global view in mind, such that these do not trigger new problems. Or in other words: we are looking for sustainable solutions, carefully balancing the use of different resources such as environmental, economical, and social-cultural resources in such a way that the contribution to local and global problems is minimised or are at least known and accounted for.

2 Model

The quantification of the sustainability indicators is based on a model that represents the mass balances of the domestic water system. This model is constructed as a superstructure by superimposing a large number of known options for the supply of different water sources (drinkingwater, householdwater, and rainwater), in-house water disinfection, water conservation, and wastewater treatment ranging from smallscale onsite treatment to large-scale systems that serve complete urban areas. In the model structure, 37 simple static models of 13 different technologies are contained in the processing units. The optimisation selects a combination of technologies resulting in a complete model of a domestic water system.

To gain insight into the sustainability of wastewater treatment systems we developed a sustainability assessment, which is a combination of existing tools, such as life cycle assessment, cost-benefit analysis, and social inventories. The main features that make the combination more than a sum of the parts are: the broad scope, the set of sustainability

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3 Optimisation

We defined the selection of optimal systems as a multi-objective integer optimisation problem. Important objectives in selecting sustainable domestic water systems are: minimise costs, the use of resources such as water, energy and space, maximise the production of clean water,

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nutrients, and biomass for reuse, minimise harmful waste products, maximise social-cultural embedding through acceptance, participation, and stimulation of sustainable behaviour. To combine these sometimes contradicting objectives, the different sustainability indicators quantifying these different objectives have to be normalised and weighted such that they can be integrated into a single final objective for optimisation. To select optimal domestic water systems for different cases, we experimented with different solvers. However, we found that due to the large number of possible combinations, about 7*1012 different water systems are contained in the decision support tool, and the discrete changes in sustainability it is difficult to find global optima within a reasonable calculation time. Therefore, we choose to reduce the problem size by defining a smaller solution space in the form of two scenarios of which the results are discussed below.

is reported in the recent literature. The reuse of water will probably trigger decentralised treatment of rainwater and greywater and may introduce low-flush or even dry toilets and disinfection of drinking water on household scale. For nutrient recycling decentralisation is not necessary although collection and reuse of urine and compost may trigger this as well. While affordable systems for nutrient recycling and minimising drinking water are available, water recycling seems to be expensive due to the choice for a membrane bioreactor. Further research is needed to find out whether the tool selects cheaper systems such as wetlands if realistic changes are made to data on removal rates, incoming streams, and restriction. Since no trade-off between domestic reuse and fertiliser was found, it is very well possible to combine the goals of our two scenarios and construct domestic water systems that recycle both nutrients and water, thereby approaching life support systems.

We defined two scenarios, to select solutions that could help to fulfil the water challenge of this new millennium. These scenarios are: (1) systems for nutrient recycling, and (2) systems for water scarce condition aiming at minimizing drinking water use and maximising water reuse. In both scenarios we searched for affordable solutions being aware that poverty is a major issues still in many parts of the world. Based on the technology choices made by the decision support tool we can conclude that technologies not commonly used today, such as urine separation, membrane bioreactors, and rainwater systems, may become important in future domestic water systems that aim at the reuse of nutrients and water. We did not find the more conventional solutions due to the fact that we aim at recycling of nutrients and water while most studies aim at comparing and optimising existing treatment systems. Furthermore, the sludge treatment included in the decision support tool is limited. If clean sludge can be produced and/ or reused in different ways then the treatment configurations based on conventional treatment may be promising too. Still, based on the selections made by the decision support tool and its present settings we conclude that, if future domestic water systems aim at nutrient and water reuse, it is likely that the conventional systems will have to be replaced by new systems that allow separation of wastewater streams at the source, a conclusion that is very much in line with what

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Zonnecellen Prof.dr.ir. Richard van de Sanden Faculteit Natuurkunde

Bij de faculteit Technische Natuurkunde zijn Dr.ir. Bas Korevaar en ook Dr.ir. Arno Smets gepromoveerd op onderzoek naar de productie van amorf silicium zonnecellen, allebei projecten in het kader van de TU/e-stimuleringsregeling Technologie voor Duurzame Ontwikkeling (TDO). Ir. Ioana Volintiru is momenteel nog bezig met haar onderzoek op een stukje van ditzelfde onderwerp, ook deels gefinancierd door TDO. Het onderzoek betreft de snelle productie van zonnecellen van amorf silicium. Amorf betekent dat de atomen niet geordend zijn volgens een kristalrooster. Cellen van amorf silicium zijn naar verwachting goedkoop te produceren, omdat er minder silicium voor nodig is dan zonnecellen op basis van kristallijn silicium. Bovendien vergt de productie minder energie, want de temperatuur tijdens de productie hoeft niet zo hoog te zijn. De energieterugverdientijd van amorf silicium kan daarom korter zijn dan die van kristallijn silicium. Een ander voordeel is dat je met amorf silicium een heel dun laagje kunt aanbrengen op een flexibele ondergrond. Dergelijke zonnecellen zijn veel eenvoudiger toe te passen. Je kunt bij wijze van spreken een mat uitrollen. Het extreem dunne laagje silicium met een dikte van 400 nanometer wordt door middel van depositie oftewel opdamping vervaardigd met behulp van een plasma, een heet geïoniseerd gas. Voor deze depositie wordt een in Eindhoven ontwikkelde cascadeboog-plasmareactor gebruikt, die bij het instituut DIMES in Delft staat opgesteld. Deze depositietechniek, waarop de TU Eindhoven patent heeft verworven, wordt ETP genoemd, wat staat voor expanderend thermisch plasma.

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Solar cells Prof.dr.ir. M.C.M van de Sanden, Department of Applied Physics At the Department of Applied Physics, Dr.ir. Bas Korevaar and Dr.ir. Arno Smets both completed their PhD projects on the subject of production of amorphous silicon solar cells. Both of the projects were financed by the TU/e incentive arrangement for sustainable development (techniek voor duurzame ontwikkeling (TDO)). Ir. Ioana Volintiru is studying a subset of the same subject, also partly financed by TDO. The research area is the quick production of solar cells from amorphous silicon. Amorphous means that the atoms are not arranged according to a crystal lattice. Cells of amorphous silicon are expected to be cheaper to produce because less silicon is required. Moreover, the production requires less energy, as the temperature does not have to be raised that high. The energy payback time of amorphous silicon therefore is shorter than that of

Volgens Prof.dr.ir. Richard van de Sanden wordt er bij de faculteit Natuurkunde al jaren fundamenteel onderzoek aan plasma’s en aan deposities van dunne lagen met behulp van plasmatechniek. De stimuleringsregeling van TDO is volgens Van de Sanden als het ware het zaad geweest om het onderzoek verder op te tuigen: hierdoor kreeg de groep een kritische massa. Twee halve AIO-4 plaatsen zijn gefinancieerd door deze stimuleringsregeling, daarbij financierde Novem de andere helft van deze plaatsen. Bij het binnenhalen van deze financiering was de toezegging voor de stimuleringsregeling van TDO essentieel, want dergelijke subdidies krijg je alleen als je eigen universiteit ook een bijdrage levert.

geld van de onderzoeksprojecten Heliantos I en II. Dat zijn door NOVEM-Senter gesubsidieerde samenwerkingsprojecten van Akzo Nobel, TNO en de universiteiten Delft, Utrecht en Eindhoven. Doel is de industriële ontwikkeling en toepassing van flexibele amorf silicium zonnecellen. Deze projecten geven een goede inbedding voor verder onderzoek. Ook bij de opzet van de nieuwe masteropleiding Sustainable Energy Technology (SET) is de invloed van TDO terug te vinden. Zowel een onderwijs-case als ook een college zijn opgezet door de ‘zonnecel groep’, een groep waarbij Van de Sanden nauw samenwerkt met Prof.dr.ir. Rene Janssen en Prof.dr.ir. Ronald van Zolingen. Volgens Van de Sanden is dit gezamenlijke initiatief van de faculteiten Technische Natuurkunde, Scheikundige Technologie en Werktuigbouwkunde een spin-off van de TDO stimuleringsregeling.

Het resultaat is dat er nu een established group is gevormd die kan werken aan verschillende aspecten van de depositietechniek. Voor de stimulering waren er slechts twee promovendi werkzaam op het gebied van de amorfe silicium zonnecel, deze promovendi werkten toen nog sequentieel: de ene begon in 1989 de andere daarop volgend in 1994. De interne stimuleringsgelden hebben de groep dus de kritische massa verschaft om een belangrijke positie te verwerven in het onderzoek naar amorfe silicium zonnecellen. Na de TDO-AIO’s Korevaar, Smets en Volintiru is het onderzoek voortgezet zonder geld van de TU/e zelf, maar met

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crystalline silicon. Another advantage of amorphous silicon is the ability to apply a

on the area of amorphous silicon solar cells. These PhD students worked sequentially:

thin layer to a flexible base. Such solar cells are far easier to apply. It would be as easy

one started in 1989; the other as a follow-up in 1994. The critical mass created by the

as rolling out a mat with cells. An extremely thin layer of silicon with a thickness of

internal TDO incentive made it possible to reach an important position in the research

400 nanometers can be made via vapor deposition, using a cascade arc reactor. This

on amorphous silicon solar cells. After the TDO-PhD students Korvaar, Smets and

arc reactor was developed in Eindhoven and built at the DIMES institute in Delft. This

Volintiru, the research will be continued without financing of the TU/e. The projects

deposition technique, which the TU/e has patented, is called ETP, which stands for

are now being financed using money from research projects Heliantos I en II. These

Expanding Thermal Plasma.

projects are funded by NOVEM-Senter in which Akzo Nobel, TNO and the universities Delft, Utrecht and Eindhoven take part. The goal is the industrial development and

According to Prof.dr.ir. Richard van de Sanden, the fundamental research on plasmas

application of flexible amorphous silicon solar cells. These projects are a good basis

and the deposition of thin layers using a plasma technique has already been done for

for further research.

years at the Applied Physics department. Van de Sanden thinks of the TU/e incentive arrangement for sustainable development (technologie voor duurzame ontwikkeling

The influence of TDO is also visible when you consider the start-up of the new Master’s

(TDO) as a kind of seed that helped to create some critical mass for the research in his

track Sustainable Energy Technology (SET). Thew solar cell group offers both a project

group. Two PhD positions were 50% financed by the incentive, and 50 % by NOVEM.

and a course; Van de Sanden closely cooperates with Prof.dr.ir. René Janssen and

To obtain the NOVEM support the promise of the incentive from TDO was essential, since

Prof.dr.ir. Ronald van Zolingen in this group. According to Van de Sanden, this

subsidies given by NOVEM are only supplied if the university also pays a certain part.

cooperative initiative of the departments Applied Physics, Chemical Engineering and

This resulted in the formation of an established group working on several aspects of

Mechanical Engineering is a spin-off of the TDO incentives.

the deposition technique. Before the incentive, only two PhD students were working

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Integration of Expanding Thermal Plasma deposited hydrogenated amorphous silicon in solar cells The set-up has been designed and built in Eindhoven by the GTD and the group “Equilibrium and Transport in Plasmas” and placed at the Delft Institute of MicroElectronics and Submicron technology (DIMES) in Delft. The first goal of the project is to realise a-Si:H solar cells with an initial efficiency of 7% that incorporate an intrinsic layer that has been deposited at a deposition rate larger than 2 nm/s with the ETP method.

Promotors: Prof.dr.ir. M.C.M. van de Sanden and Prof.dr. C.I.M. Beenakker Copromotor: Dr. R.A.C.M.M. van Swaaij Department of Applied Physics, NOVEM (Nederlandse onderneming voor energie en milieu bv) Department of Informatie Technologie en Systemen (Technische Universiteit Delft)

The material properties of the intrinsic layer depend on the deposition rate and the deposition temperature. To be incorporated into solar cells the intrinsic layer needs to have a low defect density and a high response to light. From the research performed in the new CASCADE set-up it is shown that at a particular deposition rate an optimum in material properties is achieved at a certain deposition temperature. For the conventional technique (~0.15 nm/s) this optimum is at ~2000C. For the larger deposition rates of the ETP method the optimum deposition temperature shifts to 2500C and 4000C for 1 and 10 nm/s, respectively.

Bas Korevaar - 2003 - Department of Applied Physics Solar cells are a possible energy source for the future. However, at this moment solar electricity is still more expensive than electricity from oil and gas. Several types of solar cells are available on the market amongst which are solar cells based on hydrogenated amorphous silicon (a-Si:H). A considerable reduction in the production time and thus a reduction in the production costs of a-Si:H solar cells can be realised when the intrinsic layer of this type of solar cells is produced at higher rates.

For p-i-n solar cells one has to take care that the deposition temperatur of the intrinsic layer is below 2500C, because at higher temperature the p-layer deteriorates and the cell will not operate very well. At higher deposition temperature the hydrogen diffuses out of the p-layer, which results in an increase in defect density in this layer. This temperature requirement means that the deposition rate is limited to rates < 1 nm/s for p-i-n cells. This limitation is avoided for cells deposited in the n-i-p sequence.

In previous Ph.D. research at the Eindhoven University of Technology on the expanding thermal plasma (ETP) deposition technique it was shown that a-Si:H can be deposited ~50 times faster than with the conventional technique, Radio Frequency Plasma Enhanced Chemical Vapour Deposition (RF-PECVD), while maintaining the quality required for incorporation in solar cells. This patented TU/e method uses a thermal plasma that expands in a low-pressure vacuum chamber, which results in a directed transport of reactive particles to the substrate where the a-Si:H film grows at large growth rates (0.2-10 nm/s).

P-i-n solar cells have been made in which the intrinsic layer has been deposited at deposition rates of 0.85 nm/s. The highest achieved initial efficiency at this growth rate is 6.7%. This is ~3% lower than for very good cells prepared with RFPECVD and only 1.3% lower than for a cell deposited completely in the RF-PECVD chamber of CASCADE. However, the deposition rate of the i-layer with the ETP method is roughly four times larger. The lower efficiency is due to a lower fill factor, which points towards more recombination in the solar cells. However, the bulk defect density of ETP a-Si:H and RF-PECVD a-Si:H are similar. Simulations have shown that a higher defect density in the i-layer near the p-i interface can explain the lower fill factor while not affecting

A new set-up has been designed and built in which it is possible to makecomplete solar cells without vacuum breaks in between the different layers of the p-i-n structure. This set-up was named CASCADE, which is the acronym for: Cascaded Arc Solar Cell Apparatus Delft Eindhoven. The project is a co-operation between the Eindhoven and the Delft University of Technology and is financed by NOVEM and TDO.

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Growth Related Material Properties of Hydrogenated Amorphous Silicon the open-circuit voltage and short-circuit current density. A solution to overcome extra defects at the p-i interface is to use a buffer layer, which is deposited with RF-PECVD at very low growth rates. From this it is found that a p-layer thickness of 5 nm already results in an increase in fill factor of more than 10%.

Promotors: Prof.dr.ir. M.C.M. van de Sanden and Prof.dr.ir. D.C. Schram Department of Applied Physics Equilibrium and Transport in Plasmas, Center of Plasma Physics and Radiation Technology

In order to incorporate intrinsic layers deposited at high deposition temperature and large growth rates in p-i-n cells the effect of a buffer layer between the p-layer and the intrinsic layer has been studied. When the higher deposition temperature of the intrinsic layer deteriorates the p-layer the most important difference in the solar cell performance is the lower open-circuit voltage. By applying a buffer layer in such case it is observed that the open-circuit voltage increases drastically with increasing buffer layer thickness and saturates at a buffer layer thickness thicker than 20 nm. However, the saturation value of the open-circuit voltage is not as high as expected from low deposition temperatures, but the increase makes clear that it is possible to protect the p-layer against high deposition temperatures. By applying a buffer layer with a thickness of 50 nm an initial solar cell efficiency of 5.4% has been achieved with the i-layer deposited at a deposition temperature of 3500C and a deposition rate of 1.3 nm/s. More research is needed to optimise the buffer layer.

Arno Smets - 2002 - Department of Applied Physics The realization of ultra high hydrogenated amorphous silicon (a-Si:H) growth rates (>10 Å/s) is one of the main issues affecting cost reduction in the production process of thin film a-Si:H solar cells. Until now, the expanding thermal plasma (ETP) deposition technique and the hotwire chemical vapor deposition (HWCVD) technique are the only two techniques which have obtained good material properties at ultra high growth rates of 100 Å/s. To optimize the a-Si:H growth rate and the material properties, more insight into the a-Si:H growth is required. In this thesis the a-Si:H film properties deposited by means of the ETP technique are studied. Furthermore, the relation of the material properties with a-Si:H growth from the remote ETP deposition is studied.

Finally, some investigations are started to make n-i-p solar cells. The advantage of these types of solar cells is that high deposition rates can be used because the n-type layer can be made temperature resistant up to a temperature of 4000C. So far, an efficiency of 2.8% is achieved with the i-layer deposited at a deposition temperature of 3500C and a deposition rate of 1.5 nm/s.

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The ETP technique is based upon the creation of an Ar/H2 plasma in a cascaded arc at subatmospheric pressure. This plasma expands into a low pressure reactor in which silane is injected. In the conditions studied, the silane is mainly dissociated by the hydrogen atoms and the result is a SiH3 dominated radical beam. Growth rates obtained range from 2 Å/s up to 120 Å/s. Due to the remote character of the ETP plasma the ion bombardment at the growth surface is absent or negligible. Consequently the a-Si:H growth by means of the ETP technique is based on pure radical-surface interactions. The work in this thesis is devoted to increasing the insight into the relation between the a-Si:H material properties of hydrogenated amorphous silicon films and the growth mechanisms.

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exponent β on the substrate temperature can also be simulated using a solid on solid model with a surface diffusing species having an activation energy of approximately 1.0 eV. These results suggest that a chemisorbed surface radical rather than a weakly absorbed radical is responsible for the surface smoothening by diffusion.

The role of H in the a-Si:H network formation has been studied. The hydrogen in high quality a-Si:H is responsible for the low defect densities (~1015–1016 cm-3) compared to pure a-Si material and consequently related to the opto-electronicproperties of the material. The analyses of infrared spectra has been used to study the hydride types in the material and its relation to the film density. The Si-H bonds in the a-Si:H network of the ETP a-Si:H samples are mainly monohydrides. Two distinct density regions have been found, one region dominated by vacancies and one region dominated by voids. Furthermore, the dependence of the vacancy and void incorporation in the film on the growth rate and substrate temperature reveals that two different mechanisms govern the hydrogen incorporation. The void incorporation is due to an inactive surface diffusion of a Si containing species, whereas the vacancy incorporation is a result of the probability that a hydrogen elimination step does not occur at the surface.

The surface dangling bonds are believed to play a key role in the aSi:H growth since they act as a growth sites for the dominant SiH3 growth precursor. Up to now only the in situ electron spin resonance (ESR) technique [S. Yamasaki, J. Non-Cryst. Solids 266-269, 529(2000)] was used to monitor the surface defects during a-Si:H growth. In this thesis we propose to use the cavity ring down (CRD) absorption technique as an additional tool to monitor the surface defects. The technique has been tested on a-Si:H films deposited by means of the ETP technique. The absorption in the a-Si:H spectral sub gap range (1.17 eV) has been measured. The bulk and surface related cavity loss are deduced. It is suggested that besides bulk defect absorption, bulk scattering mainly contributes to the bulk cavity loss, whereas the surface defects absorption mainly contributes to the surface cavity loss. The sensitivity to surface defects of the CRD technique has also been used to monitor the surface defects in situ, in a so-called mirrortrapezoid prism-mirror cavity configuration.

Furthermore, the question of which material properties can be related to the growth processes is also addressed in this thesis. Several techniques have been used to characterize the a-Si:H film properties. The photoconductivity in the void dominated region and the optical band gap show a relation with the a-Si:H network structure. Moreover the optimum material properties (defect density, photoconductivity, Urbach energy, microstructure factor) show a general dependence in the growth rate-substrate temperature space: increasing the growth rate, while maintaining the high quality a- Si:H, also requires an increase in the substrate temperature. The underlying principle of this dependence is a thermally activated surface process. Since it has been demonstrated that the deposition of dense films requires an activated surface diffusion, we have used an additional tool, i.e. the study of the roughness evolution of the a-Si:H surface, to gain more insight into the underlying mechanism of the surface diffusion. It is discussed in this thesis, that the scaling behavior, expressed in scaling exponents, is a signature of the dominant surface smoothening mechanism. The atomic force microscopy (AFM) technique and the single wavelength rotating compensator ellipsometry (RCE) technique have been used to monitor the roughness evolution. The homebuilt RCE setup and the analyses of the ellipsometric data are discussed in more detail. The observed dependence of the growth

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Deposition and characterisation of doped (p-type and n-type) ZnO for solar cell and LED applications Promotor: Prof.dr.ir. M.C.M. van de Sanden

References

Department of Applied Physics

1

R. Groenen, J.L. Linden, H.R.M. van Lierop et al., Appl. Surf. Sci. 173 (2001) 40-43

2

Y.R. Ryu, T.S. Lee, H.W. White, Appl. Phys. Lett. Vol. 83, No. 1, 7 july 2003, 87-89

3

C.H. Park, S.B. Zhang, S.-H. Wei, Phys. Rev. B 66, 073202 (2002)

4

C.H. Park, S.B. Zhang, Su-Huai Wei, Phys. Rev. B, 66, 073202 (2002)

Ioana Volintiru - lopend - Department of Applied Physics Zinc oxide (ZnO) is a promising transparent conductive oxide (TCO) as front electrode in solar cells. High quality n-type undoped and Aldoped ZnO by means of a thermal expanding plasma were already obtained in a previous project [1]. Also first insight into plasma chemistry and film properties was made. In order to obtain semiconductor devices, it is necessary to obtain also p-type ZnO, which, according to several authors [2,3,4], can be done by incorporating dopants as As, Li or N in the lattice, but has not been obtained in a remote plasma yet. In the present project both n and p-type ZnO thin films will be deposited, using an argon/oxygen/diethylzinc plasma and mainly aluminium (from trimethylaluminium, for n-type) and nitrogen (from N2, NO) for p-type doping. A detailed study of plasma chemistry will be made, by means of optical emission spectroscopy, mass spectrometry, Langmuir probe, Cavity Ring Down Spectroscopy measurements in order to gather more information about the species contributing to the film growth. In-situ real time spectroscopic ellipsometry will be used to monitorize the film growth. The properties of the obtained films will be established using Atomic Force Microscopy, X-Ray Diffraction, Hall measurements, Fourier Transformed Infrared Spectroscopy.

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The Rate-Limiting Factor of the Solid Oxide Fuel Cell back to the cathode providing electricity to an external load. In order to make the SOFC economically and technically viable the current operating temperature of around 1000°C has to be reduced to the intermediate temperature range of 500 - 800°C. Before lowering the operating temperature, the currently limiting process, the surface oxygen exchange, has to be improved. The research described in this thesis has, therefore, focussed on the oxygen exchange characteristics in relation to the composition of the outermost surface layer of the YSZ electrolyte, where the oxygen exchange takes place.

Promotoren: Prof.dr. H.H. Brongersma and Prof.dr. J.W. Niemantsverdriet Copromotor: Dr. R.G. van Welzenis Department of Applied Physics

Low energy ion scattering (LEIS) is the only surface science technique that is capable of probing the outermost surface layer and quantifying its atomic composition. To study the YSZ surface with LEIS, water and hydrocarbon residues, adsorbed on the surface due to the transport through air, should be removed without changing the properties of the layer lying just beneath this contaminant overlayer. In a real SOFC system the contaminants at the cathode side are removed, because the SOFC is operated at 1000°C in oxygen. These conditions are, however, very difficult to implement in a UHV system and another method is, therefore, required. Thermal oxidation at 500°C is possible, but is not sufficient to produce clean YSZ surfaces. A new procedure, which consists of a high vacuum annealing treatment at 300°C followed by an oxidation treatment using atomic oxygen at a pressure of 10-4 mbar for 10 minutes, is, therefore, proposed and tested. Crucial to this cleaning process is the separation of the annealing and oxidation treatment and the cleaning of the vacuum system before each cleaning step. A clean YSZ surface is very reactive and therefore highly susceptible for cross-contamination and re-adsorption of previously desorbed species. The cleaning process complies with the imposed requirements.

Marco de Ridder - 2002 - Department of Applied Physics Fossil fuels have played a major role in the technological development and economic growth of the last thirty years, but are now held responsible for the increase in air pollution and the global climate change. In light of future generations these life threatening changes have to be stopped. A large contribution to this process can be made by using fuel cells. The fuel cell converts chemical energy directly into electrical energy and heat without combustion. They are inherently clean, efficient and compatible with renewable energy sources. One of the most appealing aspects of the fuel cell is its modularity, making a wide range of applications possible from large power plants to power supplies for cellular phones. The solid oxide fuel cell (SOFC) is one of the five existing types of fuel cells. They are mainly considered for stationary power generation, although other uses are being considered. The efficiency of the SOFC power plant lies between 50 and 70% and increases up to 90% in case of cogeneration. These efficiencies are much higher than conventional power plants. The key component of the SOFC is an yttria stabilized zirconia (YSZ) electrolyte, which is sandwiched between a cathode (e.g. La0.65Sr0.3MnO3) and an anode (e.g. Ni/YSZ). In operation, oxygen gas molecules are supplied to the cathode side of the electrolyte, where they are converted to oxygen ions. These ions will diffuse through the electrolyte to the anode side, where they react with the supplied hydrogen gas under the formation of water and the release of two electrons per created water molecule. The electrons are transported

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With a clean YSZ surface, the changes in the surface composition due to high temperature calcination treatments could be studied. An YSZ ceramic material, however, invariably contains glassy impurity oxides, such as silica, calcia and sodium oxide. These oxides are observed to segregate to the outermost surface layer of YSZ at elevated temperatures. Although the impurity oxides are restricted to the outermost layer, the enrichment proceeds until full coverage. Because of the strong segregation a total bulk impurity level of 10 ppm, which is a factor 100 lower than the impurity level in the currently available YSZ powders,

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will still poison more than half of the YSZ surface. In contrast to the conventional thinking, yttria does not accumulate in the outermost layer, but in the layer just beneath the surface. Because yttria resides in the subsurface layer it cannot participate actively in the oxygen exchange processes which are so important for the SOFC. Compared to the bulk the subsurface layer of 3 and 10 mol% yttria doped zirconia samples are enriched in yttria by respectively a factor 6 and 4.5 at 1000°C. From the Arrhenius plot the interfacial free energy for yttria segregation in zirconia could be determined to be –21 kJ/mol.

should be kept from the YSZ surface, e.g. through the addition of a species with a lower surface free energy than the impurity oxides or by trapping the impurities in the bulk. Addition of a catalyst could improve the oxygen exchange even further. Iron oxide is a likely candidate, because its low surface free energy will keep it from migrating into the bulk and because iron can change its valency in highly oxidising conditions at 1000°C. However, the presence of iron oxide on impurity free YSZ does not change the oxygen exchange. Mention of improvement in literature by this method is mainly to be blamed on the simultaneous removal of impurity oxides as a consequence of the deposition technique used. Also, the presence of iron oxide on the surface does not prevent impurities from segregating to the surface during calcination at temperatures in excess of 800°C. The results even suggest the formation of a compound between the impurity oxides and iron oxide, resulting again in an effective barrier for oxygen exchange.

The incorporation of oxygen into the electrolyte is a kind of Mars van Krevelen process, which means surface cations should be able to change their valency to be effective in the oxygen exchange process. The surface composition, therefore, has a major influence on the exchange characteristics, which is shown by the oxygen exchange experiments on YSZ samples with different impurity oxide coverages. In this kind of experiments the YSZ sample is calcined in isotopically labeled oxygen after which the exchanged oxygen concentration is determined at the surface, but also in deeper layers. When a monolayer of impurity oxides covers the YSZ surface completely no oxygen is exchanged at the surface. A decrease in the impurity coverage causes a proportional increase in the surface oxygen exchange. For a surface that is free from impurities more than half of the surface oxygen is already exchanged within 10 minutes at 500°C. Due to their stability, the impurity oxides at the YSZ surface form a barrier for oxygen exchange and although the exchange experiments pertain to a temperature of 500°C, the results show that at 1000°C the surface is still covered by impurities.

The research has lead to new insights, which are very important to the development of the SOFC. From the external surface, four different layers can be distinguished: a monolayer impurity oxides, a monolayer yttria enriched YSZ, a 6 nm thin YSZ layer with a very low diffusion coefficient and the bulk. To lower the operating temperature the impurity oxides should be removed from the external surface. However, as impurities will also segregate to the grain boundaries, removing the impurities completely will increase the performance even further. With the removal it should be possible to operate the SOFC at temperatures as low as 725°C.

Removal of the impurities not only caused a significant improvement of the oxygen exchange it also revealed the presence of a 6 nm thin YSZ layer at the external surface with an oxygen self-diffusion coefficient which is 4 – 10 orders in magnitude lower than that of cubic bulk YSZ. At least as far as the oxygen transport characteristics are concerned a comparison with the monoclinic phase is apparent. The thickness of this layer is, however, too small to have a significant influence on the oxygen diffusion through the electrolyte. To increase the oxygen exchange considerably the impurity oxides

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Atomic and Molecular Excitation Processes in Microwave Induced Plasmas A Spectroscopic Study experimental conditions, for which generally commercially available laboratory equipment is not suited, has been clearly demonstrated. A large variety of elements (like zinc, lead, sodium and magnesium) could be easily detected quasi-simultaneously. In general, emission spectra of the studied microwave induced plasmas are dominated by emission of diatomic molecules that are generated in the plasma itself (C2, CN, NO, OH, NH). Since interference with these molecular bands can disturb the detection of element lines, dissociation and association processes have been studied. Results of this investigation can also be used to find out whether it is possible to analyze molecules with plasmas. For this purpose experiments with different molecular gases have been performed. It is found that at atmospheric pressure 3-body association processes play an important role. Moreover, it is concluded that in free expanding torches molecular emission bands are inevitable as a result of air entrainment. At reduced pressure (~1-10 mbar) the importance of 3-body processes is limited. However, it is found that in this pressure regime association at the wall of the discharge tube is important (which is a process with two atoms or molecules and the wall as a substitute for the third body). Although, unlike for the atmospheric discharges, under some conditions diatomic dissociation products are observed when 3-atomic molecules are injected (CO emission after CO2 injection), no conditions are found in which originally injected molecules are observed in emission (except for nitrogen). Moreover, since matrix effects are readily observed, i.e. changes in the concentration of a certain element/molecule affect the emission of another element/molecule, it can be concluded that the analysis of molecular gas mixtures with plasmas will be very complex. Excitation balances and transport properties in free expanding plasma torches have been studied by means of so-called interruption experiments, in which the power of the microwave generator is momentary interrupted (typically 60 µs). In the active part of the plasma it is found that the injection of molecular gases has a large influence on the responses of emission lines to power interruption. Significant changes are observed, even for less than 1% of molecular gas injection. The agreement of the measurements in the recombining plasma zone with an established relationship between the intensity decay time of some element lines and the decay time for the gas temperature, suggests that in this zone the corresponding radiative levels are populated by thermal excitation. From the fast decay times of line intensities that

Promotoren: Prof.dr.ir. D.C. Schram and Prof.dr. J.A.C. Broekaert Copromotor: Dr. J.A.M. van der Mullen Department of Applied Physics

Eric Timmermans - 1999 - Department of Applied Physics Plasmas nowadays play an essential role in many industrial processes and laboratory applications. Some well-known examples are deposition and etching of layers, cutting and welding, waste treatment, cleaning of detrimental gases, light generation and spectrochemical analysis. In this thesis different microwave induced plasmas (MIPs) are investigated with respect to the latter application. The technique of atomic emission spectroscopy (AES) has become very popular during the last 20 years, especially for the elemental analysis of aqueous samples. The plasma is used to evaporate and atomize the sample and excite elements present in the sample. The emission that is generated by the spontaneous decay of excited levels provides information on these elements. Typical detection limits of AES when a so-called inductively coupled plasma is used as excitation source are around 1 ppb for most elements (1 ppb ≅ 1 ng/ml). By applying different plasma sources (i.e. the 'torche à injection axiale', the microwave plasma torch, the Beenakker cavity, the surfatron and the guide-surfatron) a large variety of plasma conditions is obtained. With various spectroscopic studies more insight is obtained in plasma processes related to spectrochemical analysis. It is found that many MIPs have a high tolerance to the introduction of molecular gases. Accordingly, the 'torche à injection axiale' has been used successfully for the on-line monitoring of the flow of metals in combustion gases in the secondary combustion chamber of AVRChemie, a large hazardous waste incinerator in the Netherlands. The potential of this torch for measurements under extremely rough

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result from electron excitation, information is obtained on diffusion and convection losses. Moreover, the axial gas flow velocity is determined from the propagation of a disturbance thatis created in the active part of the plasma. Finally, density profiles of the argon metastable 4s3P2 level have been determined in free expanding plasmas via diode laser absorption. The populations of the 4s levels constitute a decisive factor for the stepwise excitation and ionization of argon. Moreover, these levels can be responsible for Penning ionization of other elements. It is found that the 4s3P2 density is maximal in the active part of the plasma, where the plasma has a hollow cone-like structure. Abel-inversion has shown that the distribution of the 4s3P2 profile is less steep in this region than that of the electron density. The 4s3P2 density points towards an electron temperature of 1.3 eV, which is significantly less as determined with Thomson scattering (2.0 eV) but is in rather well agreement with the temperature that can be calculated from the particle balance (1.1 eV). Experiments with molecular gas injection have established that molecules quench the population of the 4s3P2 level. The broadening and the shift of central frequency of the absorption profile have been used to study trends in plasma parameters (such as gas and electron temperature and electron density).

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Onderzoeken op Duurzaamheidsgebied aan de Technische Universiteit Eindhoven

Duurzaam Bouwen

Ir. A.A.M. van Vliet, Arch. Faculteit Bouwkunde / BTO 'A sustainable and healthy environment for single older women' and 'The life-zone adaptable dwelling' S. Di Cicco, Arch. Faculteit Bouwkunde / BTO 'Design aids for healthy and sustainable hospital buildings' Prof.mag.arch. P. Schmid Faculteit Bouwkunde / BTO 'Essentials of sustainable building-ESB';'Strategies for sustainable building' and 'Straw panel systems-SPS' and 'Light metal systems-LMS' Ir. J. Janssen Faculteit Bouwkunde 'Rethinking the productive landscape. The spatial transformation of the Brabant countryside, 1890-1990' Ir. H. van Nunen Faculteit Bouwkunde / FAGO 'Physical and sustainable/technical optimization of the IFD today-apartment building system' Ir. A.W.M. van Schijndel Faculteit Bouwkunde 'Integrated building physics and systems modeling and simulation' Ir. F.J.M. van Gassel Faculteit Bouwkunde 'An Industrial, Flexible and Demountable multistorey building system' Ir. S.F.A.J.G. Zegers Faculteit Bouwkunde / CO 'Development of an Industrial, Flexible and Demountable Floor System' Ir. M. Ham Faculteit Bouwkunde / BTO 'Building technology and solar energy'

Ir. J.F.M. Boelen Faculteit Bouwkunde / BTO 'The architectural counterpoint' Drs. J. Czabanowski Faculteit Bouwkunde / BTO 'Human Ecologically Minded Building' F. de Medts Arch.lic. Faculteit Bouwkunde / BTO 'Building Constructions and Structures in Wood' and 'Towards a new building method' E. Mosiniak, Arch. Faculteit Bouwkunde 'Sound buildings investigations, cases, and advices for feeling good and environmentally conscious therapeutic buildings' Drs. T. van Pinxteren Faculteit Bouwkunde 'The growth and dimensions of chrildren’s territory' Drs.ir. C.M. Ravesloot Faculteit Bouwkunde 'Rombo Tactics - Development of a method for effective realization of energy-neutral housing in the Netherlands' Ir. W.H.M. Schijns Faculteit Bouwkunde / BTO 'The evolution of a West-African vernacular culture' and 'Sustainably built heritage' Mag. G. Schuster Faculteit Bouwkunde / BTO 'Solar Architecture - Implementing and transferring aspects for a postgraduate university program'

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A.R. Pereira, MSc Faculteit Bouwkunde / BTO 'Rearchitecture: lifespan rehabilitation of built heritage' Prof.ir. J.M. Post Faculteit Bouwkunde / BTO 'Design for life span' Ir. G.J. van den Brand Faculteit Bouwkunde / BTO 'Analysis of sustainable design concepts' Dr.ir. P.A. Erkelens Faculteit Bouwkunde / BTO 'Infrastructure for different temporary life span' Dr.ir. R.J. Dierkx Faculteit Bouwkunde / BTO 'Cool schools for hot suburbs Nairobi, Kenia' Prof.dr.ir. J. Lichtenberg Faculteit Bouwkunde / BTO 'Smart and lean building' Ir.ing. A. van der Zee Faculteit Bouwkunde / Ontwerpsystemen 'A method for evolutionary development of design alternatives subject to a set of performance constraints and user requirements'

Dr. A. Toland & Ir. H.A.J.A. van Kuijk Faculteit Werktuigbouwkunde / Combustion Technology 'EU project OPTICOMB' Dr. J.A. van Oijen Faculteit Werktuigbouwkunde / Combustion Technology 'VENI project New Combustion Concepts for Ultra-(c)lean Engines' Ir. P.J.M. Frijters & A. Evlampiev, MSc Faculteit Werktuigbouwkunde / Combustion Technology 'Modeling of the combustion process in a direct injection diesel engine' Ir. E. Doosje Faculteit Werktuigbouwkunde / Combustion Technology 'TNO project Ultra-(c)lean Combustion' Ing. R.T.E. Hermanns Faculteit Werktuigbouwkunde / Combustion Technology 'Greening of Gas' M. Salama Abd-Elhady, MSc Faculteit Werktuigbouwkunde / Energy Technology Group 'Fouling of heat-exchange equipment used in waste incinerators and biomass gasifiers' L.G. Grabowski, MSc Faculteit Natuurkunde / EPG 'Ytrid: Remediation of Acqeous and Gaseous Waste Streams by Pulsed Corona Discharge in Heterogeneous Media' X.Y. Zhu, MSc & Ir. T. Nimalasuriya Faculteit Natuurkunde / EPG 'Arges (Atomic Densities measured Radially using Emission Spectroscopy)' Ir. C.M.L. Scholz Faculteit Scheikunde / Laboratory of Chemical Reactor Engineering 'A model-based controller for diesel and lean-burn engines, to optimize both emissions and fuel consumption'

Energie Dr.ir. R.J.M. Bastiaans Faculteit Werktuigbouwkunde / WVM 'Burning stability of biogas/methane mixtures' Dr. Albrecht & Ir. J. de Swart Faculteit Werktuigbouwkunde / Combustion Technology 'STW project Influence of Biogas Addition on the Flame Stability of Lean Premixed Gasturbine Combustors'

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Ir. E.R. Delsman Faculteit Scheikunde / Laboratory of Chemical Reactor Engineering 'Micro reaction technology for hydrogen and electricity production' I. Volintiru, MSc Faculteit Natuurkunde / ETP 'Plasma deposition of p-type transparant conductors' J.H. Guo, MSc Faculteit Natuurkunde 'Pyrolysis of wood powder and gasification of wood-derived char' Ir. T.A. van der Hoeven Faculteit Werktuigbouwkunde / Energy Technology 'Tar removal from biogas through partial oxidation' L. Devi, MSc Faculteit Scheikunde / Environmental Technology 'Primary measures for inhibition of tar formation in biomass fuelled fluidised bed gasifier' Ir. M.J. Prins Faculteit Scheikunde / Environmental technology 'Design of a biomass gasifier in view of technical, economical and psychological parameters' and'Torrefaction for entrained-flow gasification of biomass'

Ir. O. Dos Santos Ferreira Faculteit Scheikunde / SVM 'A mesoscopic materials approach to adhesion' Dr. S. Fischer Faculteit Scheikunde / SVM 'Advanced highly filled nanocomposites' Ir. S. Kisin Faculteit Scheikunde / SVM 'Adhesion of metal on plastic: adhesion and adhesion change, a model study' Dr. D.J.W. Lensveld Faculteit Scheikunde / SVM Fundamental research into the effects of surface modifications at aluminium and zinc' Drs. Y.Q. Li Faculteit Scheikunde / SVM 'Rare-earth actived (oxy)nitrides' Drs. Z. Li Faculteit Scheikunde / SVM 'Adhesion properties in coatings' Dr.ir. A.J.D. Lambert Factulteit Technologie Management / OPAC 'Kwantitative models of industrial ecology' Z.O. Oyman, MSc & Drs. F. Micciche Faculteit Scheikunde / SVM 'Environmentally friendly alternatives to co-catalyst during the drying of alhyd coatings' Drs. W. Posthumus Faculteit Scheikunde / SVM 'IOP-Kras en slijtvaste coatings van de Linde' Drs. F. Scaltro Faculteit Scheikunde / SVM 'Durability of coating-metal interfaces'

Duurzame Productie Dr. E.D. Sourty Faculteit Natuurkunde / Polymer Physics Group 'Microstructure and micromechanics of hydrocarbon C-fix composites' Ir. A. Adallah Faculteit Scheikunde / SVM 'Mechanical integrity of laminar multi-material structures' T. Dikiç, Dipl.ing. Faculteit Scheikunde / SVM 'Self replenishing low adherence coatings'

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Drs. D. Senatore Faculteit Scheikunde / SVM 'Low temperature curing of powder coatings by encapsulated cross-linkers' Ir. W.J. Soer Faculteit Scheikunde / SVM 'Waterborne anti-corrosion coatings for magnesium surfaces' Dr. V. Soloukhin Faculteit Scheikunde / SVM 'Application of electro active polymers in environmentally friendly anticorrosive treatment of metals (TELMAB)' Ir. D. Wu Faculteit Scheikunde / SVM 'Topologically structured super hydrophobic termoset coatings' Prof.dr. R. van Benthem Faculteit Scheikunde / SVM 'Durability of industrial coatings' Dr. J. Laven Faculteit Scheikunde / SVM 'Dispersing pigments in waterborne paints' Ir. B.A.J. Noordover Faculteit Scheikunde / SPC 'Biobased building blocks for coating and toner resins' Dr. R.J. Sablong Faculteit Scheikunde / SPC 'Biobased co-monomers for polyesters and polycarbonates suitable as engineering plastic resins' Ir. A.J.M. van Dijk Faculteit Scheikunde / SPC 'A three step route to polymides for engineering plastic applications' Drs. W.J. van Meerendonk Faculteit Scheikunde / SPC 'CO2 as monomer for phosgene-free synthesis of new polycarbonates'

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Onderzoeken

Dr. S.A.Y. Mulder Faculteit Scheikunde / SPC 'Production of polyolefins by an emulsion polymerization process' Ir. M. de Geus Faculteit Scheikunde / SPC 'Enzymatic catalysis in the preparation block copolymers' Dr.ir. J.M. de Gooijer Faculteit Scheikunde / SPC 'Chemical modification of polymers in supercritical C02' Dr. F.D. Wiesbrock Faculteit Scheikunde / SKA/SMO 'Microwave assisted synthesis' Ir. V.N. Marin & Dr. E.K. Holder Faculteit Scheikunde / SKA/SMO 'Polypyridyl Ruthenium(II) Complexes for Solar Cells Applications' Dr.ir. E. Snijders Faculteit Scheikunde / SKT 'Water Expandable Polystyrene' N. Cabrera, MSc Faculteit Scheikunde / SKT 'All-PP Composites I' Ing. B. Tuerlings Faculteit Scheikunde / SKT 'All-PP Composites II' B. Alcock, MSc Faculteit Scheikunde / SKT 'All Plastic Composites' Z.P. Masende, MSc Faculteit Scheikunde / Laboratory of Chemical Reactor Engineering 'Catalytic wet oxidation of wastewater: phenol oxidation over platinum-based metal catalysts' Ir. C.P. Stemmet Faculteit Scheikunde / Laboratory of Chemical Reactor Engineering 'Solid foams: novel structured packings for gas-liquid reactors'

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Ir. M.J.F. Warnier Faculteit Scheikunde / Laboratory of Chemical Reactor Engineering 'Microstructured process architectures for advanced chemical synthesis' Dr.ir. P.A.G.M. Scheren Faculteit Scheikunde / Environmental Technology 'Integrated water pollution assesment in developing countries' I.Greeff, MSc Faculteit Scheikunde / Environmental Technology 'Recovery of work from exothermic chemical reaction systems by means of turbine expansion' Prof.mr.dr.ir. S.C. Santema Faculteit Tecnologie Management / OSM 'Sustainable outsourcing, definations and positionering'

Ir. W.M. v.d. Hoogen Faculteit TeMa / MTI Human Technology Interaction 'Public acceptance of biomass as sustainable energy source: consequences for development and implementation' Dr. L.T. McCalley Faculteit TeMa / MTI Human Technology Interaction 'Eco Feedback 3, a field study' Prof.mag.Arch. P. Schmid Faculteit Bouwkunde / Multidisciplinair Centrum voor technische vraagstukken van Vrede en Veiligheid 'Building for sustainable peace' Dr.ir. G.P.J. Verbong Faculteit TeMa / AW 'Study in system innovation and strategic niche management' Dr. A.L. Meijnders Faculteit TeMa / MTI - Human Technology Interaction 'Trust in GM Food' Ir. R.P.J.M. Raven Faculteit TeMa / AW 'Strategic Niche Management for Biomass' Dr.ir. S.D.P. Flapper Faculteit Technische Bedrijfskunde / OPAC 'Logistics planning and control of rework'

Gedrag en Voorlichting Dr. F.G. Kaiser & Prof.dr. C.J.H. Midden & A. Geven Faculteit TeMa / MTI Human Technology Interaction 'Environmental Motivation & Performance in Eindhoven, a goal-directed behavior approach' Dr. L.T. McCalley Faculteit TeMa / MTI Human Technology Interaction 'The role of the litter bin as an instrument to reducewaste' Drs. F.N.H. Montijn-Dorgelo 'Faculteit TeMa / MTI Human Technology Interaction Social acceptance of hydrogen as an energy carrier; feeling of risk and experience of control' Ir.ing. K. Haagdorens Faculteit TeMa / MTI Human Technology Interaction 'Use of interactive feedback agents as companies to support household energy conservation goals'

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Colofon

The TDO-Researchbook is a publication of The Centre of Technology for Sustainable Development (TDO) Pav. A. 58 P.O.Box 513 5600 MB Eindhoven The Netherlands Telephone + 31 (0)40 2474463 fax +31 (0)40 2439475 [email protected] www.tue.nl/tdo

Text Dr.ir. Marja Houben, Interviewer TDO Translation Drs. Steven Ralston (CTT) Editor-in-chief Ria Overwater, Office Manager TDO Assistant editor Jessica Peters, Student-assistant TDO Photography Norbert van Onna, Veldhoven Design vanRixtelvanderPut ontwerpers, Eindhoven Printer Drukkerij Lecturis, Eindhoven

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