Catalytic gasification

LTU Biosyngas Program:

Catalytic gasification

Overall project summary report Erik Furusjö, Division of Energy Sciences, LTU 2016-12-23

Overall project summary report LTU Biosyngas Program – Catalytic gasification

Erik Furusjö 2016-12-20

Summary The “Catalytic gasification” research project was coordinated by Luleå University of Technology 20132016. The catalytic effect of alkali is an important reason for the successful demonstration of black liquor gasification based biofuels production in previous projects. The overall objective of this project was to investigate if catalytic entrained flow gasification can be used to improve efficiency and/or decrease biofuel production costs also for other feedstocks than black liquor. Two main fields were investigated: black liquor/pyrolysis oil co-gasification and alkali catalyzed solid biomass gasification. The results of the project are reported in 8 project sub-reports, 9 scientific conference presentations and 14 peer-reviewed scientific articles (of which 6 are still in the peer review stage at the time of writing). Results from black liquor/pyrolysis oil entrained flow co-gasification experiments in lab and pilot scale shows that blending BL with the more energy-rich PO can increase the process efficiency without adversely affecting process performance. In pilot scale, carbon conversion was in the range 98.8% to 99.5% for both BL and PO/BL blends and did not vary systematically with fuel type. The cold gas efficiency increased by about 5%-units for a 20% PO blend compared to only BL due to the decreased inorganic ballast. For demonstration and of long term testing, over 1000 h of cogasification operation in pilot scale was accumulated without noticing any problematic long term effects. Over 850 h of this time included syngas upgrading to DME, meaning that this project was the first ever to produce significant amounts of biofuel from PO. The longest continuous run was more than seven days. PO/BL co-gasification is a technically and economically attractive production route for production of biofuels with similar costs as for a biofuels based on BL gasification. The main advantages from a techno-economic perspective are: feedstock flexibility (PO can be made from many different feedstocks) and the uncoupling of plant capacity from BL flow. The latter means that either a part of the BL flow from a mill can be used or that larger plants can be built, which can lead to a lower the total investment requirement to meet the total biofuel demand in the system. The catalytic solid biomass gasification investigations in this project concerns two partly separate tracks: precipitated kraft lignin and wood biomass (for example sawdust or milled forest residues). Potassium carbonate can be an efficient catalyst for entrained flow solid biomass gasification, allowing substantially lower process temperatures to be used with maintained carbon conversion and decreased soot and tar formation. A number of positive effects are obtained, including improved operability and improved biofuel yield from raw biomass. The possibility of alkali catalyst recovery means that the production costs are not increased compared to normal, non-catalytic, gasification. For precipitated kraft lignin, the normally practised washing step can be omitted to obtain both lower production costs and a lignin more suitable for catalytic gasification. Gasification of unwashed lignin shows greatly improved carbon conversion as well as decreases soot and tar formation compared to standard lignin. A techno-economic study shows that kraft lignin as a gasification feedstock provides added economic benefits for biofuel production only if lignin production costs can be decreased, for example by including a value from increased pulp production at the exporting mill.

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Table of contents 1

Introduction ..................................................................................................................................... 4

2

Project objectives ............................................................................................................................ 5

3

Result summary ............................................................................................................................... 6 3.1

Co-gasification of pyrolysis oil and black liquor ...................................................................... 6

3.1.1

Mixing pyrolysis oil and black liquor ............................................................................... 6

3.1.2

Lab scale experiments - fundamental understanding ..................................................... 6

3.1.3

Pilot scale experiments – demo and applied knowledge ................................................ 7

3.1.4

Techno-economic study .................................................................................................. 9

3.2

Catalytic solid biomass gasification ....................................................................................... 10

3.2.1

Lignin precipitation and costs........................................................................................ 10

3.2.2

Mixing lignin and black liquor........................................................................................ 10

3.2.3

Solid lignin and lignin/black liquor mixtures ................................................................. 11

3.2.4

Alkali impregnated solid biomass .................................................................................. 12

3.2.5

Techno-economic study ................................................................................................ 12

4

Graduate student training ............................................................................................................. 14

5

Scientific publication ..................................................................................................................... 14

6

5.1

Journal articles....................................................................................................................... 14

5.2

Conference presentations ..................................................................................................... 15

List of project deliverables ............................................................................................................ 15

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1 Introduction This report is an overall project summary report for the “Catalytic gasification” research project (Energimyndigheten 38026-1) coordinated by Luleå University of Technology with research work carried out at Luleå University of Technology, SP Energy Technology Center and Innventia between December 2013 and December 2016. The project was financed by the Swedish Energy Agency, Luleå University of Technology, Piteå Kommun, Landstinget Norrbotten and Haldor Topsö. Two important starting points for the project are 1) the established pilot scale operating experience of black liquor (BL) gasification and 2) the scientific literature on the importance of alkali catalysis in black liquor gasification, which leads to improved process efficiency and a very clean syngas suitable for biofuel production. If this catalytic effect can be realized in commercial scale also for other feedstocks it can potentially lead to improved efficiency and/or decreased biofuel production costs. Two main fields were investigated in the area of feedstock flexibility: black liquor/pyrolysis oil cogasification and alkali catalyzed solid biomass gasification. A lab scale pre-study in 2012 had indicated that pyrolysis oil (PO) could be co-gasified with BL with maintained catalytic effect from BL alkali and that co-gasification technology could potentially have a significant impact on the possibility to produce biofuels for the Swedish transportation system. This project provides demonstration in an industrially relevant scale and good estimates of technoeconomic performance in order to bring the co-gasification technology closer to commercialization. Different technologies for production of biofuels through gasification of solid biomass, including fixed and fluidized beds as well as entrained flow reactors, are under development by many actors. Increased efficiency is important in relation to limited biomass supply and can potentially lead to lower production costs. The project aimed to investigate if a catalytic effect from alkali metals can offer a potential way to significantly increase the efficiency of the gasification of solid biomass and thus increase biofuels production potential. The project included a technical and techno-economic feasibility study for catalytic gasification of solid biomass. This report summarizes the most important results from the project with references to more extensive reports for the reader who is looking for more details. Project economics are reported separately and thus not treated here. As a project manager, I would like to express my gratitude to all the people working in the project. I have learned a lot from working with you and together we have managed to reach a lot of very interesting results that can help Sweden and other countries to significantly advance the possibilities for production of biofuels and green chemicals from forest biomass. We have shown how to turn alkali, which is mostly considered problematic in biomass conversion, to an advantage!

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2 Project objectives The objectives of the project as stated in the Energy Agency decision are listed below in translated form. All objectives have been fully met. 1. Develop co-gasification technology for black liquor and pyrolysis oil and prepare commercialization by: a. executing co-gasification experiments in DP-1 with a total accumulated operating time of 1000 hours and thereby verify and demonstrate the technology b. Show that high carbon conversion can be achieved in pilot scale, quantify process performance and other critical design data for a commercial implementation and develop practical understanding of the process chemistry c. Make recommendations for the design of an efficient co-gasification technology based on understanding of the experiments in laboratory and pilot scale d. Quantify the potential of the technology from a techno-economic perspective for various realistic scenarios with regard to the prices of biomass and pyrolysis oil 2. Give a first basic assessment of commercial opportunities for the catalytic gasification of wood powder and lignin powder by: a. Demonstrating that a catalytic effect can be achieved by gasification of alkali impregnated wood powder in laboratory scale, quantifying the effect and investigating the technical possibilities for the catalytic gasification of wood powder b. Demonstrating that a catalytic effect can be achieved for residual or added alkali during gasification of lignin powder in laboratory scale, quantifying the effect and investigating the technical possibilities for catalytic gasification of lignin powder c. describing the technology's basic potential from a techno-economic perspective 3. Use fundamental studies of catalytic gasification to build theoretical and scientific knowledge of catalytic gasification by a. performing pyrolysis and gasification experiments in laboratory scale and reporting conclusions on co-gasification process chemistry for black liquor, black liquor/pyrolysis oil, alkali impregnated wood powder and lignin powder b. quantifying the differences in reactivity and char properties of the various raw materials and develop a theoretical model to explain these differences c. train three graduate students involved in this project

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3 Result summary 3.1 Co-gasification of pyrolysis oil and black liquor A major part of the research executed in the project is concerned with co-gasification of PO and BL. Experiments were made both in lab and pilot scale to quantify performance and increase process understanding. Techno-economic evaluations were based on the understanding developed.

3.1.1 Mixing pyrolysis oil and black liquor1 In order to efficiently co-gasify BL and PO they must first be mixed, since the gasifier only has one fuel inlet. BL/PO mixing is influenced by the acids present in PO. The acids limit the fraction of PO that can be mixed into BL without causing precipitation of the BL dissolved lignin, which occurs if the mixture pH is below approximately 11. The project results show that a simple model based on PO total acid number can be used to predict the maximum PO fraction in blends. A total PO acid number (TAN), including weak phenolic acids, is a more relevant measure of PO acid content than the standard acid number, which for PO mainly includes stronger carboxylic acids. The maximum PO fraction that can be mixed into BL is typically 20−25% by mass, corresponding to 30-40% by energy but it can be increased up to at least 50% by mass, corresponding to 70% by energy, by addition of a base to the mixture. Excess alkali in BL typically has a relatively large variation during normal operation of a pulp mill. Since this alkali is important for the maximum PO fraction that can be used without precipitation, a commercial co-gasification plant should include control of this parameter. The results related to PO/BL mixing are detailed in D1.1a and D1.1b.

3.1.2 Lab scale experiments - fundamental understanding2 Lab scale gasification experiments using a thermogravimetric analyser (TGA) and a drop tube furnace (DTF) were used for fundamental investigations of PO/BL co-gasification. Since the conditions that can be obtained in lab equipment can never be fully representative for a commercial plant, BL was used as a reference fuel in all experiments The pilot scale gasification behaviour of BL is fairly well known. The TGA study using up to 30% PO in BL (D2.2a, D2.2b) confirmed the hypothesized strong catalytic activity of alkali metals inherent in BL during gasification. Quantification of single droplet conversion times showed that PO/BL mixtures converted 30 times faster than pure PO and comparable to BL. Char gasification for PO/BL mixtures at temperatures up to 860 °C was comparable to that of pure BL. The combined results suggest that fuel mixtures containing up to 30% of PO on mass basis may be feasible in existing BL gasification technology. The TGA study, however, was limited to temperatures up to 860 °C, which is lower than is encountered in a commercial entrained flow gasifier. The use of a DTF allowed more representative 1

Research contributions from: Erik Furusjö (LTU), Esbjörn Pettersson (SP ETC) Research contributions from: Albert Bach Oller (LTU), Kawnish Kirtania (LTU), Kentaro Umeki (LTU), Erik Furusjö (LTU) 2

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conditions to be studied at temperatures up to 1400 °C and up to 40% PO in BL. The high temperatures enhanced alkali release in the gas phase. However, the concentration of alkali left in the particles remained high and no decrease in catalytic activity was observed due to alkali loss. Additionally the PO/BL blends showed better carbon conversion than pure BL at identical conditions. The conversion rate of large particles (500-630μm) was controlled by mass diffusion. Small fuel particles showed complete conversion at 1000 °C but larger particles did not reach complete conversion even at T= 1400 °C for neither BL nor PO/BL. This indicates that atomization can be of great importance in a commercial gasification process but the particle size limits of the lab study is not necessarily relevant for pilot or commercial scale due to different process conditions. In comparison with pine-wood, which was used as a reference, BL/PO samples showed much lower tar concentrations in the syngas, which was attributed to alkali elements. Remarkably, the addition of PO to BL further promoted tar reforming in the presence of carbon dioxide. The addition of PO also significantly increased the yields of methane and carbon monoxide. In summary, the results from the fundamental lab study indicate that PO/BL blends gasify equally well or better than BL with respect to most performance parameters. If this is extrapolated to pilot scale conditions it means that similar process conditions (temperature, pressure, residence time etc.) could likely be used to process PO/BL mixtures as pure BL.

3.1.3 Pilot scale experiments – demo and applied knowledge3 Pilot scale co-gasification experiments were executed in the LTU Green Fuels pilot plant in Piteå, Sweden. The plant was designed for BL gasification and built by Chemrec using their pressurized oxygen blown BL gasification technology. The plant comprises a full process chain from feedstock to biofuel product, including the following steps: gasification, gas conditioning (active carbon filter, water gas shift, acid gas removal), gas compression, methanol synthesis, DME synthesis and DME purification. In order to use the plant for PO/BL co-gasification, some additions were necessary and implemented as a part of this project. A PO storage and feeding system was designed and built. The system comprises a 55 m3 outdoor PO tank, a 2 m3 indoor PO tank and pumps to pressurize and feed PO to the gasifier. A high pressure mixer was used to mix BL and PO at 30 bar and 140 °C before feeding to the gasifier. No additions or modifications were required for the gasifier itself or the downstream equipment. The pilot plant modification work is described in D1.2a. The pilot plant experiments executed in this project were grouped in four separate parts: BL reference runs, initial co-gasification experiments, parametric study for process performance quantification and long term experiments. For the experiments, BL was supplied by the Smurfit Kappa Kraftliner mill that is integrated with the pilot plant. Fortum supplied a total of 120 t of PO by truck during the period September 2015-march 2016. The origin of this oil was the Fortum pyrolysis plant in Joensuu, Finland. BTG-BtL supplied 48 t of oil transported by ship and truck. The origin of this oil was the BTG-BtL Empyro pyrolysis plant in Hengelo, Netherlands.

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Research contributions from: Yawer Jafri (LTU), Erik Furusjö (LTU), Fredrik Granberg (LTU GF), Jonas Jönsson (LTU GF), Gustav Lindberg (LTU GF), Rikard Gebart (LTU)

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A 5-day campaign in June 2015 was used for a parametric study to quantify co-gasification process performance and sensitivity to variations in fuel blend and temperature. In summary, the results from the pilot tests confirm the theoretical prediction that blending BL with the more energy-rich PO can increase the cold gas efficiency and improve the process carbon distribution without adversely affecting either carbon conversion or the general process performance. Carbon conversion was in the range 98.8% to 99.5% for both BL and PO/BL blends and did not vary systematically with fuel type. The cold gas efficiency increased by about 5%-units for a 20% PO blend compared to only BL due to the decreased inorganic ballast. The fraction of feedstock sulfur released as H2S varied between 3135% for the PO/BL blends very similar to the 28-31% obtained for BL. The decrease in fuel inorganic content with increasing PO fraction resulted in more dilute green liquor (GL) since the water feed was not decreased proportionally. A detailed scientific account of these results can be found in D1.3c, D1.3d and D1.3e. An overview is also available in D1.3a.

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Accumulated PO consumption (tons)

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For demonstration and of long term testing, over 1000 h of co-gasification operation was accumulated without noticing any negative long term effects. Over 850 h of this time was operation with the full process chain to DME, meaning that this project was the first ever to produce significant amounts of biofuel from PO. The longest continuous run was more than seven days. By the time the project came to an end, the plant had recorded more than 1000 hours of operation on blends with up to 20 wt% PO, corresponding to ~32% on an energy basis. Based on these results from the long term runs, blending BL with PO does not appear to give any negative effects. More details can be found in D1.3a. The long term pilot experiment results have not been published in a scientific journal at the writing of this report but an abstract has been submitted to a scientific conference (D1.3h).

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Figure 1. Accumulated co-gasification operating hours and PO consumption in the pilot plant during the project (from D1.3a). Initial experiments/proof-of concept not shown in graph but included in the numbers.

Design recommendations were made for a commercial plant using Chemrec BL gasification technology as a baseline. The major design changes required in order to adapt the BL gasification design for co-gasification is the addition of a PO handling and feeding system and a BL/PO mixer. In addition, the GL dissolver needs to be adapted for the lower smelt flows in order to give a GL of correct concentration. More detailed design recommendations can be found in D1.3a.

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3.1.4 Techno-economic study4 Thermodynamic equilibrium calculations were used to understand the effects of blend composition, including any added base that can be used to increase the maximum PO fraction, on the performance of a commercial scale gasification process. A substantial increase in overall gasification efficiency is observed with increasing PO fraction (see D1.1b). Similar thermodynamic models were also used in two studies concerning a techno-economic evaluation of the co-gasification technology (see D1.4a, D1.4b, D1.4c). The two techno-economic studies performed accounted for different scenarios. The first study (D1.4a, D1.4b) concerned retrofitting a specific mill with a co-gasification based methanol plant and looked at the effect of the amount of PO added as well as the effect of the PO price on the profitability. The results show that gasifying a blend consisting of 50% PO and 50% BL on a wet mass basis increases the methanol production by more than 250%, compared to gasifying the available BL only. Co-gasification would be an attractive investment opportunity when the price for PO is less than 70 €/MWh. The economic evaluation was based on a first plant estimate with no investment credit for the recovery boiler and a methanol product value volumetric equivalent to conventional ethanol. The second study (D1.4c) looked at mature (nth plant) co-gasification technology for integration with pulp mill of various sizes and assumed a PO cost of 42 €/MWh, which believed to be a realistic long term estimate. It is concluded that gasification of pure BL and PO/BL blends up to 50% results in significantly lower production costs than what can be achieved by gasification of unblended PO. Cogasification with 20–50% oil addition gives the lowest production costs for small pulp mills whilst pure BL gasification gives lower costs for larger pulp mills due to decreasing economies of scale. It is concluded that the required methanol selling price is below 80 €/MWh for the best cases and the obtained production capacities at a single plant range from 0.9 to 1.6 TW h/y for pure BLG, and from 1.2 to 6.5 TW h/y for PO/BL co-gasification. The main conclusion of the techno-economic studies is that PO/BL co-gasification is a technically and economically attractive production route for production of biofuels. Biomethanol is used as the product in the cases studied but the technology can be used to produce a range of fuels including synthetic natural gas (SNG), dimethyl ether (DME) and synthetic diesel. The use of PO/BL cogasification leads to similar costs as for a methanol plant based on BL gasification. The main advantages of the co-gasification track from a techno-economic perspective are: 1. feedstock flexibility, since PO can be made from many different feedstocks including various wastes and residues 2. the uncoupling of plant capacity from BL flow, which means that larger biofuels plants can be built at a specific mill or, alternatively, that only a part of the BL flow can be used and still obtain reasonable scale of the plant (this latter alternative was not studied specifically in the project but is an important topic for further research)

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Research contributions from: Jim Andersson (LTU), Erik Furusjö (LTU), Joakim Lundgren (LTU), Elisabeth Wetterlund (LTU), Ingvar Landälv (LTU)

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3. by introducing PO/BL co-gasification, fewer pulp mills would need to be converted to biofuel plants than with pure BLG, to meet a certain biofuel demand for a region. Due to the technical as well as organizational complexity of the integration this may prove beneficial, and could also potentially lower the total investment requirement to meet the total biofuel demand in the system.

3.2 Catalytic solid biomass gasification The catalytic solid biomass gasification investigations in this project concerns two partly separate tracks: precipitated kraft lignin and wood biomass (for example sawdust or milled forest residues). For wood biomass, alkali impregnation was investigated as a method for improving an entrained flow gasification process, as discussed in 3.2.4 below. For Kraft lignin, two separate options were investigated: co-gasification with BL, which in reality creates a liquid feedstock, as well as gasification of solid lignin in dry form, see 3.2.2 and 3.2.3 below. Techno-economic evaluations for both feedstock options are discussed in 3.2.5. Adding lignin from an external pulp mill to BL introduced into a gasifier is a way of transferring energy from one pulp mill to another, for example because the exporting pulp mill has a production bottle-neck in the recovery boiler while the receiving pulp mill has a process that can efficiently use and valorize that energy, for example a biofuels plant.

3.2.1 Lignin precipitation and costs5 LignoBoost is a commercial process for precipitating kraft lignin from BL. A washing step, using sulphuric acid, gives a lignin with very low alkali content and low pH (around 2). Since one of the purposes of this project is to investigate the catalytic effect of alkali salts, a modification to the LignoBoost process in which the washing step was removed was introduced. This gives a lignin with high pH that contains about 7% Na compared to 0.2% for washed lignin (see D3.2a for details). Reduced pulp mill power generation is one of the most important factors for lignin production costs from BL in modern pulp mills. The removal of the washing step has effects on the mill chemicals balance since it extracts alkali with the lignin. A study was done to investigate the influence of this on production costs for the lignin. The results show that for the case studied the production cost for washed lignin is higher, 38-39 €/MWh, than the cost for unwashed lignin, 33-36 €/MWh. The primary reason is the reduced costs associated with the washing step (investment and sulphuric acid consumption). It should be noted that this cost does not include any benefits from increased pulp production that can be enabled by reducing the load on a capacity limiting recovery boiler. Hence, the real production costs for lignin can be lower than the numbers arrived at in this study. Details about the lignin production cost estimation can be found in D3.2d.

3.2.2 Mixing lignin and black liquor6 Technically, lignin addition to BL increases the heating value, carbon content and absolute energy supplied to the gasifier in order to increase its total energy conversion and reduce the specific 5

Research contributions from: Marie Anheden (Innventia), Jens Wolf (Innventia), Anna Jensen (Innventia)

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Research contributions from: Marie Anheden (Innventia), Anna Jensen (Innventia)

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investment cost of the gasifier. However, adding lignin to BL is limited by the increase of the mixture viscosity. The results from mixing tests using 65% DS BL show that the viscosity of the mixture is affected to a lesser extent when unwashed (high alkali, high pH) lignin from the first precipitation step of the LignoBoost process is added compared to similar amounts of standard (low alkali, low pH) lignin. Standard lignin can safely be added up to about 5% (wt lignin/wt BL) to the BL without significantly increasing the viscosity of the mixture. The addition of up to 15% washed lignin resulted in a viscosity that is expected to be difficult to manage in the evaporator and BL gasifier. Attempts to reduce the viscosity through heat treatment were unsuccessful. For unwashed lignin on the other hand, mixtures with up to 15% are believed to be feasible without causing major problems during evaporation and gasification. Based on the results from the mixing tests, increasing the energy intake to the mill with up to 28% through addition of up to 15% unwashed lignin and increasing the heating value of the liquor up to 12% is feasible, if unwashed lignin is added to the BL. If washed lignin is added, the lignin addition should be limited to about 5% based on the effect on viscosity. This is equivalent to an increase in the heating value of less than 5% and an energy intake increase with about 10%. The details of the BL/lignin mixing study can be found in D3.2a.

3.2.3 Gasification of solid lignin and lignin/black liquor mixtures7 The gasification characteristics of solid lignin and lignin/BL mixtures were investigated for both washed, low-alkali lignin and unwashed high-alkali lignin. Initial low temperature TGA experiments showed that unwashed lignin is much more reactive than washed lignin due to alkali catalysis but that the reactivity of unwashed lignin is still lower than for BL. To obtain results that are more representative for a commercial entrained flow gasifier, high temperature lab scale gasification in a DTF at 1000-1200 °C was used. These showed that washed lignin displayed low carbon conversion and that 20-40% of fuel carbon ended up as soot, tar and char residue. The amount of soot, constituting around 10% of the feed, is 2-3 times as high as that observed for the pine saw dust reference but the amount of tar generated is slightly lower than for pine. In total, this indicates that washed lignin is a very poor gasification fuel. The situation is drastically different for high-alkali unwashed lignin. This feedstock gives less than 2.5% unconverted carbon and practically no soot at 1000-1200 °C. Tar formation for unwashed lignin is low at T=1000°C but the same as for washed lignin at T=1200°C. The combined results indicated that unwashed lignin can be an attractive gasification feedstock. It is more reactive than washed lignin and also shows significantly higher conversion rate than pine saw dust and similar feedstocks. For the BL/lignin blends the situation is different and the presence of alkali in the lignin does not appear to be as important for gasification performance. The blends of BL and lignin behaved very similarly to BL with respect to soot formation and carbon conversion regardless of whether the lignin had been washed or not. It can be concluded that the alkali present in BL is enough to provide 7

Research contributions from: Albert Bach Oller (LTU), Gustav Häggström (LTU), Kawnish Kirtania (LTU), Kentaro Umeki (LTU), Erik Furusjö (LTU)

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catalytic activity also for lignin conversion in the case with BL/washed lignin and that form a fuel conversion perspective BL/lignin mixtures can likely be gasified under the same conditions as for pure BL. Details about low temperature experiments can be found in D3.2b and about more representative high temperature experiments in D3.2c.

3.2.4 Alkali impregnated solid biomass8 Low temperature gasification experiments in a TGA were used to screen the effect of different impregnation methods and alkali catalysts on impregnated biomass gasification behaviour. The results, detailed in D3.2e and D3.2f, shows that potassium carbonate is the most promising catalyst. There are several reasons for this choice besides the good catalytic activity; potassium is naturally abundant in biomass and hence, has an inherent make-up in a catalytic cycle. In addition, alkali salts mainly leave the gasifier in the form of carbonates, which means that catalyst recycling is facilitated without the need to upgrade/process the catalyst. The reactivity increase measured for potassium carbonate impregnated saw dust is so high that approximately the same conversion time is obtained for alkali impregnated saw dust at 1150 °C as for unimpregnated saw dust at 1500 °C. Hence, the gasification of impregnated wood can take place at a much lower temperature than the 1400-1500 °C that is typical for non-catalytic entrained flow gasification of solid biomass. High temperature gasification experiments in a DTF at 900-1400 °C, detailed in D2.3g, show that the improved char conversion rate is sustained also at those temperatures. In addition, it is shown that soot formation, which can be problematic for non-catalytic entrained flow gasification of solid biomass, is decreased more than 10 times by catalyst impregnation. The tar formation is also decreased significantly in the relevant temperature interval around 1000 °C. It can be concluded that impregnation of biomass with a catalytically active alkali salt, potassium carbonate, seems to offer many advantages for entrained flow gasification. The increased char conversion rate enables much lower temperatures to be used, which can improve efficiency, and the positive effect on tar and soot formation can decrease gas clean-up requirements.

3.2.5 Techno-economic study9 3.2.5.1 Lignin/black liquor mixtures A study was made concerning the techno-economic feasibility of producing biomethanol through cogasification of BL with up to 15% blend ratios of standard and unwashed lignin (see 3.2.1 and 3.2.2). The methanol plant is designed as fully integrated with a state-of-the-art pulp mill. Two grades of methanol are evaluated, namely crude methanol as maritime transport fuel and grade AA methanol as automotive fuel. The evaluation is done using a differential approach by comparing a reference case (standard pulp mill).

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Research contributions from: Albert Bach Oller (LTU), Gustav Häggström (LTU), Kawnish Kirtania (LTU), Kentaro Umeki (LTU), Erik Furusjö (LTU) 9

Research contributions from: Lara Carvalho (LTU), Erik Furusjö (LTU), Joakim Lundgren (LTU), Elisabeth Wetterlund (LTU)

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The study shows overall conversion efficiencies from BL/lignin feedstock to methanol of 49-53% but considering the pulp mill integration, which includes a fuel switch for process steam production, the overall efficiency of the process is 90-95% for crude methanol and 78-82% for grade AA methanol. The corresponding numbers on electricity equivalent basis10 are 72-73% and 66-67%. These numbers are very high, indicating that the process is a highly efficient way to produce biomethanol from biomass. Required methanol selling price, assuming a 15% return on investment, is approximately 80 €/MWh for crude methanol and 90 €/MWh for grade AA methanol. These prices are very competitive compared to other second generation biofuel production routes. However, with the lignin feedstock price assumptions made (see 3.2.1), the impact of lignin mixing on production costs is (weakly) to increase them. A sensitivity analysis shows that if lignin price is decreased to the same level as used for other biomass in the study, the effect of lignin mixing is to decrease the required selling price. As noted above in 3.2.1, the actual production cost for precipitated kraft lignin is highly dependent on the specific mill and any de-bottlenecking that it can lead to. Details of this techno-economic study can be found in D3.3d.

3.2.5.2 Alkali impregnated solid biomass and solid lignin A techno-economic study concerning the use of alkali catalyzed biomass gasification in 300 MW scale for biomethanol production was made based on the technical results for potassium carbonate impregnated biomass as discussed in 3.2.4 above. Entrained flow gasification of pulverized forest residues without alkali impregnation was used as reference case. The results show that feedstock to methanol conversion efficiency increases from 62% to 65% for catalytic gasification and up to 66% if unwashed lignin is used as a complementary feedstock. This is mainly a result of the lower gasification process temperature that can be used due to the catalytic activity of the alkali. Both grade AA and crude methanol production was studied (see 3.2.5.1). For crude methanol production, the process is always self-sufficient with heat, i.e. the waste heat from the processes is enough to supply heat to biomass impregnation and drying. For grade AA methanol, extra energy supply can be needed for biomass drying due to the increased heat demand for methanol distillation. The increased efficiency associated with catalytic gasification is compensated by the increased investment costs in biomass pre-processing (mainly impregnation) so that required selling price is practically the same for the reference case and the catalytic gasification case: approximately 100 €/MWh at 15% return on capital. For cases with lignin as a complementary feedstock, the production costs are 5-10 €/MWh higher. Despite not showing lower production costs, catalytic gasification is an attractive option due to the higher biomass to methanol conversion efficiency, which is important in a future scenario where biomass is a limited resource. In addition, catalytic gasification provides operational advantages, such as improved slag behaviour and decreased formation of tar and soot. These have not been

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Recalculating energy flows to electricity equivalents is one way of including exergy (”energy quality”) in the analysis.

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quantitatively included in the present study due to lack of specific information of possible impact on costs or availability.

4 Graduate student training The PhD thesis of Jim Andersson, Luleå University of Technology, was defended in March 2016. It contains two articles about co-gasification techno-economics and the project contributed significantly to the last two years of his training. The licentiate theses of Albert Bach-Oller (October 2016) and Yawer Jafri (December 2016) were both fully based on research in this project. The PhD student Lara Carvalho, Luleå University of Technology, has worked in the project August 2015-December 2016. Her PhD thesis, planned for December 2017 will contain one journal article about techno-economics of solid biomass catalytic gasification based on research in this project.

5 Scientific publication 5.1 Journal articles 1.

Furusjö, E., Stare, R., Landälv, I., Löwnertz, P., 2014. Pilot Scale Gasification of Spent Cooking Liquor from Sodium Sulfite Based Delignification, Energy & Fuels 28, 7517–7526. 2. Andersson, J., Lundgren, J. Furusjö, E., Landälv, I., 2015. Co-gasification of pyrolysis oil and black liquor for methanol production, Fuel 158, 451-459 3. Andersson, J., Lundgren, J. Furusjö, E., Wetterlund, E. , Landälv, I., 2016. Co-gasification of black liquor and pyrolysis oil: Evaluation of blend ratios and methanol production capacities, Energy Conversion and Management 110, 240-248. 4. Jafri Y., Furusjö E., Kirtania K., Gebart R., 2016, Performance of a pilot scale entrained-flow black liquor gasifier. Energy & Fuels 30, 3175-3185. 5. Bach, A., Furusjö, E., Umeki, K., 2015. Fuel conversion characteristics of black liquor and pyrolysis oil mixtures: efficient gasification with inherent catalyst, Biomass and Bioenergy 79, 155-165 6. Kirtania, K., Axelsson, J., Matsakas, L., Christakopoulos, P., Umeki, K., Furusjö, E., 2016, Kinetic study of catalytic gasification of wood char impregnated with different alkali salts, Energy in press, DOI: 10.1016/j.energy.2016.10.134. 7. Furusjö, E.; Pettersson, E., 2016. Mixing of Fast Pyrolysis Oil and Black Liquor: Preparing an Improved Gasification Feedstock. Energy & Fuels 30, 10575–10582 8. Furusjö, E.; Jafri, Y. 2016. Thermodynamic Equilibrium Analysis of Entrained Flow Gasification of Spent Pulping Liquors. Biomass Convers. Biorefinery in press, DOI: 10.1007/s13399-016-0225-7 9. Jafri, Y.; Furusjö, E.; Kirtania, K.; Gebart, R., 2016. Thermodynamic Equilibrium Modelling of Catalytic Entrained-Flow Gasification of Biomass. Submitted for publication. 10. Bach-Oller, A.; Kirtania, K.; Furusjö, E.; Umeki, K. 2016. Co-Gasification of Black Liquor and Pyrolysis Oil at High Temperature (800-1400 °C): Part 1. Fate of Alkali Elements. Submitted for publication. 11. Bach-Oller, A.; Kirtania, K.; Furusjö, E.; Umeki, K. 2016. Co-Gasification of Black Liquor and Pyrolysis Oil at High Temperature (800-1400 °C): Part 2. Fuel Conversion. Submitted for publication. 12. Jafri, Y.; Furusjö, E.; Kirtania, K.; Gebart, R. 2016. An Experimental Study of Black Liquor and Pyrolysis Oil Co-Gasification in Pilot-Scale. Submitted for publication.

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13. Umeki, K., Häggström, G., Bach-Oller, A., Kirtania, K., Furusjö, E. 2016. Reduction of tar and soot formation from entrained flow gasification of woody biomass by alkali impregnation. . Submitted for publication. 14. Carvalho, L.; Furusjö, E.; Kirtania, K.; Wetterlund, E.; Lundgren, J.; Anheden, M.; Wolf, J., 2016. Techno-economic assessment of catalytic gasification of biomass powders for methanol production. Submitted for publication.

5.2 Conference presentations 1. 2.

3.

4.

5.

6.

7.

8.

9.

Andersson, J., Lundgren, J. Furusjö, E., 2013, Co-gasification of pyrolysis oil and black liquor for methanol production, In International Conference on Sustainable Energy Technologies. Hong Kong. Bach, A., Furusjö, E., Umeki, K., 2014. Fuel conversion characteristics of black liquor and pyrolysis oil mixture for efficient gasification with inherent catalyst, In 22nd European Biomass Conference and Exhibition. Hamburg. Andersson, J. Lundgren, J. Furusjö, E., Landälv, I., 2014. Co-gasification of pyrolysis oil and black liquor: optimal feedstock mix for different raw material cost scenarios, In Nordic Wood Biorefinery Conference. Stockholm. Furusjö E., Kirtania K., Jafri Y., Oller A. B., Umeki K., Andersson J., Lundgren J., Wetterlund E., Landälv I., Gebart R., Pettersson E., 2015, Co-gasification of pyrolysis oil and black liquor – a new track for production of chemicals and transportation fuels from biomass. in 4th International conference on thermochemical (TC) biomass conversion science, Chicago, USA, 2-5 November, Gas Technology Institute, Chicago. Bach-Oller, A., Kirtania, K., Furusjö, E., and Umeki, K., 2015, Characterization of tar and soot formation for an improved co-gasification of black liquor and pyrolysis oil, In 4th International conference on thermochemical (TC) biomass conversion science, Chicago, USA, 2-5 November, Gas Technology Institute, Chicago. Jafri Y., Furusjö E., Kirtania K., Gebart R., 2015, Entrained-flow co-gasification of black liquor and pyrolysis oil - Concept verification and assessment of gasifier performance. In 4th International conference on thermochemical (TC) biomass conversion science, Chicago, USA, 2-5 November, Gas Technology Institute, Chicago. Jafri, Y., Furusjö, E., Kirtania, K., Gebart, R., 2016, Production of Methanol and Dimethyl Ether Via Entrained-Flow Catalytic Co-Gasification of Pyrolysis Oil and Black Liquor in Pilot-Scale, In 24th European Biomass Conference and Exhibition, Amsterdam 6-9 June Kirtania, K., Axelsson, J., Matsakas, L., Furusjö, E., Umeki, K., 2016, Alkali catalyzed gasification of woody biomass with the potential of catalyst recovery. In 24th European Biomass Conference and Exhibition, Amsterdam 6-9 June Carvalho, L.; Furusjö, E.; Kirtania, K.; Lundgren, J.; Anheden, M.; Wolf, J., 2016. Techno-Economic Assessment of Catalytic Gasification of Biomass Powders for Methanol Production. In 1st International Conference on Bioresource Technology for Bioenergy, Bioproducts & Environmental Sustainability, Sitges, Spain, 23-26 October;.

6 List of project deliverables 1.1a 1.1b 1.2a 1.3a 1.3b 1.3c

Residual alkali and possibilities to increase alkali content in black liquors - implications for cogasification of pyrolysis oil and black liquor Mixing of fast pyrolysis oil and black liquor – preparing an improved gasification feedstock Pyrolysis oil feeding system including documentation Co-gasification : process demonstration, long term effects and recommendations for design of commercial co-gasification plants Pilot Scale Gasification of Spent Cooking Liquor from Sodium Sulfite Based Delignification (scientific journal article) Performance of an Entrained-Flow Black Liquor Gasifier (scientific journal article)

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1.3d

1.3e 1.3f 1.3g 1.3h 1.4a 1.4b 1.4c 2.2a 2.2b 2.2c 2.2d 2.2e 3.1a 3.2a 3.2b 3.2c 3.2d 3.2e 3.2f 3.2g 3.3a 3.3b 3.3c 3.3d


Production of Methanol and Dimethyl Ether via EntrainedFlow Catalytic Co- Gasification of Pyrolysis Oil and Black Liquor in Pilot-Scale (scientific conference presentation) An Experimental Study of Black Liquor and Pyrolysis Oil Co-Gasification in Pilot-Scale (scientific journal article) Thermodynamic Equilibrium Modelling of Catalytic Entrained Flow Gasification of Biomass (scientific journal article) Entrained-Flow Gasification of Black Liquor and Pyrolysis Oil – Pilot-Scale and Equilibrium Modelling Studies of Catalytic Cogasification (licentiate thesis) Advances in black liquor gasification: a pilot-scale study of performance improvement through cogasification with pyrolysis oil (scientific conference presentation) Co-gasification of pyrolysis oil and black liquor : optimal feedstock mix for different raw material cost scenarios (scientific conference presentation) Co-gasification of pyrolysis oil and black liquor for methanol production (scientific journal article) Co-gasification of black liquor and pyrolysis oil: Evaluation of blend ratios and methanol production capacities (scientific journal article) Fuel Conversion Characteristics of Black Liquor and Pyrolysis Oil Mixture for Efficient Gasification with Inherent Catalyst (scientific conference presentation) Fuel Conversion Characteristics of Black Liquor and Pyrolysis Oil Mixtures: Efficient Gasification with Inherent Catalyst (scientific journal article) Co-Gasification of Black Liquor and Pyrolysis Oil at High Temperature (800-1400 °C): Part 1. Fuel Conversion (scientific journal article) Co-Gasification of Black Liquor and Pyrolysis Oil at High Temperature (800-1400 °C): Part 2. Fuel conversion (scientific journal article) Co-gasification of black liquor and pyrolysis oil: Fuel conversion and catalytic activity of alkali compounds (Licentiate thesis) Feeding aspects of catalytic gasification of solid biomass Mixing solid lignin into black liquor Catalytic gasification of wood powder and lignin with physical property assessment of the feedstock High temperature laboratory gasification of lignin Production Costs for washed and unwashed Kraft lignin Kinetic study of catalytic gasification of wood char impregnated with different alkali salts (scientific journal article) Alkali catalyzed gasification of woody biomass with the potential of catalyst recovery (scientific conference presentation) Reduction of tar and soot formation from entrained flow gasification of woody biomass by alkali impregnation (scientific journal article) Alkali catalysed solid biomass gasification - pre-treatment and gasification process for wood and Kraft lignin Techno-Economic Assessment of Catalytic Gasification of Biomass Powders for Methanol Production (scientific conference presentation) Techno-economic assessment of catalytic gasification of biomass powders for methanol production (scientific journal article) Techno-economics of BL/lignin co-gasification"

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