Energy for Sustainability 2013 Sustainable Cities: Designing for People and the Planet Coimbra, 8 to 10 September 2013
LIFE CYCLE ASSESSMENT OF BIODIESEL PRODUCTION UNIT FROM FRYING OIL F. Orlandin1*, V. M. Santos1, V. G. Maciel1 ,W. Menezes1, R. Ligabue1, M. Seferin1 1: Pontifical Catholic University of Rio Grande do Sul - PUCRS School of Chemistry Postgraduate Engineering and Materials Technology - PGETEMA Av. Ipiranga, 6681 – Partenon – Porto Alegre/RS – CEP 90619-900 e-mail:
[email protected], web: www.pucrs.com.br
Keywords: LCA, Biodiesel, used cooking oil Abstract The Life Cycle Assessment (LCA) of biodiesel pilot production from frying oil was performed. This study covers used oil collection, extraction and processing of raw materials, and the biodiesel production. The production plant is a small unit, capable of produce 300 kg of biofuel each batch and the purification method for biodiesel is the impurities adsorptions on solid. The functional unit chosen was the production of 300kg of biodiesel. The categories of impact selected for this evaluation were potential of climate change, ozone depletion, acidification and terrestrial depletion of fossil resources. The Life Cycle Impact Assessment was performed by a midpoint calculation method. The results obtained showed that the methanol use is responsible for the high impacts on the production and a model for the collection step was developed for further studeis. Finally, this work brings ways to minimize the impacts of producing unit of biodiesel, fundamenting choices on LCA results.
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F. Orlandin 1*, V. M. Santos1, V. G. Maciel 1 ,W. Menezes1, R. Ligabue1, M. Seferin 1
1. INTRODUCTION The growing production and use of biofuels all over the world is gaining attention of the researchers, industy, governments ans society. Several life cycle assessment studies have been published in the last years, generally covering renewable raw material sources. Other works brought the use of residues as feedstock for ethanol, biogas and biodiesel production. Only a few of those studies take in consideration the residues collection in the life cycle inventory, an important issue to get the whole picture of the production system. For small biofuels production plants, the systems emissions reduction is another major concern, since the energy consumption and correct efluent treatment can be serious technological, economic and environmental bottlenecks. Our reseach group is now involved with an educational project that shows to young students of 15 Brazilian schools some technologial, social, environmental and economic aspects related to renewable enrgy systems focusing the life cycle of the biofuels [1]. The students are encouraged to participate of lab sessions, cultural production and research activities, among other initiatives. For the research activities, we have installed a small biodiesel production plant, for 300 kg of biodiesel for batch and the used cooking oil collected in the schools and used as the biodiesel feedstock. Due to the low production capacity of the plant, the purification of the biodiesel is performed by adsorption for reducing the amount of generated residues. Among other research projects conducted by our group with the scholars collaboration is the anaerobic digestion of glycerin, project that will have its results communicated soon. In this work, we performed a life cycle assessment for the used cooking oil conversion to biodiesel in our small plant, taking in consideration the collection of raw material from the schools, and the biodiesel production.
2. METHODS The life cycle inventory was conducted in accordance with ISO 14040 [6] and ISO 14044 [7]. Data for building the inventory were obtained from direct on site measurements for the biodiesel production. Additional data were obtained from the literature. The inventory was constructed based on the productivity of the plant, which is 300 kg of biodisel/operation. For the used cooking oil collection phase, a collect route was concieved, taking in consideration that all the schools involved in the project were collect points and the amount of the available used oil in each school was proportional to the nunber of students in the school. The weight of the collection truck is increased as the operation is executed. The truck for the operation is an Euro III with diesel motorization fueled with Diesel B5 and capacity for transport 7500 kg. For biodiesel production, methanol as reagent, potassium hydroxide as catalyst and magnesium silicate as adorbent for purification were employed. The collected used frying oils was filtered for solids removal and utilized without purification, after measuring iodine number and acidity index. The 6:1 methanol: oil molar ratio was employed, and 1 % of the oil
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F. Orlandin 1*, V. M. Santos1, V. G. Maciel 1 ,W. Menezes1, R. Ligabue1, M. Seferin 1
mass of catalyst and magnesium silicate was added to the main reactor, which is mantained at 60oC during the transesterification time, about 1 h. The methanol excess is recovered and glycerol phase is decanted and separated from reactional media before the biodiesel purification step. The methyl esters characterization and quantification was performed by gas chromatography, in a Shimazu GC17 chromatograph and methyl heptadecanoate as internal standard. 2.1. Functional Unit The functional unit (FU) is used to produce 300 kg of biodiesel. 2.2 Scope The study covered the used cooking oil collection, extraction and processing of other raw material and biodiesel production The energy and material flows are presented in Figure 1.
Fig. 1: Material flow of the biodiesel production.
2.3 Inventory and Impacts Assessment Besides the material inputs and outputs described earlier, the energy consumption for operatin the biodiesel plant was directly measured. All the heating and mass transport were supplied by electric Power. The plant is equipped with five pumps for liquids transportation, (3 x 0.4kW and 2 x 1.5kW), one vaccum pump (1.1kW). There are six electric resitances (4000 kW) for heating processes. 3
The inventory was constructed with the help of SimaPro 7.4.3v software and the impacts assessment were conducted based on ReCiPe Midpoint v1.04. The consulted database was EcoInvent 2.2. Massic allocation was applied assigning 75.7% of the impacts for biodiesel, 18.8% for glycerin and 5.5% for filter cake. As soon as the technological solutions for glycerin and filter cake can be implemented, the calculation will be done again, expanding the system without any allocation. The impact categories analyzed were Global Warming Potential, Acidification, Ozone depletion and Fossil Resources Depletion.
3. RESULTS AND DISCUSSION
3.1 Used Cooking Oil Collection For modelling the collection of used oil, the real distances among the collection points were considered and a route was created taking in account the best scenario we could concieve. The truck travels the larger steps with the lesser amounts of oil and with the shorter possible distances between two adjacent points. The table 1 displays the distances between each two sequential collection points as well as the cummulative collected weight fraction. The distance traveled for the entire route is 188 km. Stretch
A/B
B/C
C/D
D/E
E/F
F/G
G/H
H/I
60.20
39.60
6.70
5.70
11.2
2.90
5.50
3.00
0*
0.200
0.240
0.247
0.303
0.479
0.502
0.537
Stretch
I/J
J/K
K/L
L/M
M/N
N/O
O/A
Total
d (km) 1
01.20
1.50
13.10
10.6
3.30
16.60
7,50
188
0.595
0.730
0.864
0.912
0.994
1.000
1.000
d (km) φ
φ
1
2
2
0.817
Tab. 1: Distances among adjacent collection points. *point A is the first and last point. 1 – lenght of each stretch. 2 – cummulative mass fraction of collected oil.
3.2 Environmental Impacts From the constructed inventory, the impacts for four categories were calculated: Potential Glocal Warming, Ozone depletion, Terrestrial Acidification and Fossile Resources Depletion. The impacts were calculated for the feedstock produtction and transportation as well as the trasport until the biodiesel plant as well as the energy usage for all steps of biodiesel production. The nonconverted oil and emissions for the transesterification were not considered. The figure 2 shows the obtained results for those impact categories. For energy usage impact calculation, the brazilian electric energy grid was used. In all considered categories except for terrestrial acidification, the methanol production and transportation was responsible for the major impacts. Once Brazil is a great bioethanol producer, is easy to think that the etylic biodiesel could be a reasonable way for lowering this impact, but there are technologic difficulties for this reaction caused by harder phase separation for the work up of the production. The higher acidifcication potential for the collection step was probably observed because of the euro III data that was employed in the calculus. Nevertheless we should consider that the higher part of brazilian fleet is still constituted for this kind of truck. Nowadays, only euro V truck can be produced in Brazil, and this scenario is expected to be changed. 4
F. Orlandin 1*, V. M. Santos1, V. G. Maciel 1 ,W. Menezes1, R. Ligabue1, M. Seferin 1
Fig 2 – Calculated Impact: Global Warming Potential; Ozone Depletion; Terrestrial Acidification; Fossile Resources Depletion ( clockwise, from top right to bottom left).
4. CONCLUSION In conclusion, the partnership with 15 schools in our region allowed us to concieve the potential impacts from the collection step in the methylic biodiesel production. The results obtained from the collection phase showed that this step cannot be underestimated when performing life cycle assessment for any production system that employs residues as raw material. Specifically for biodisel production from frying oil, the methanol production, transport and recovery is highly important. For the next steps of the work, system expansion Will be made, including glycerol as energy resource for the biodisel production and adsorbent purification and recycling steps in the system. 6. ACKNOWLEDGEMENTS The authors acknowledge the financial support provided by FINEP (Brazilian Funding for Studies and Projects), CNPq (The Brazilian Research Council) and FAPERGS (The Scientific Research Foundation of the State of Rio Grande do Sul, Brazil), and special thanks should be given to PUCRS (Pontifical Catholic University of Rio Grande do Sul), SULGÁS (Gas Company of Rio Grande do Sul) for their collaboration with this study
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F. Orlandin 1*, V. M. Santos1, V. G. Maciel 1 ,W. Menezes1, R. Ligabue1, M. Seferin 1
7. REFERENCES [1] Projeto PROMOBIO. FINEP/CT-PETRO/PROMOPETRO, Ref. 2520/2009. http://promobio.com.br. [2] S. Froehner and J. Leithold, Transesterificação de óleos vegetais: caracterização por cromatografia delgada e densidade. Química Nova, Vol 30, 2007. [3] C. Carrareto, A. Marcor, A. Mirandola, A. Stoppato, S. Tonon. Biodiesel as alternative fuel: Experimental analysis and energetic evaluations. Energy, Vol 29, 2004. [4] J. vam Garpen. Biodiesel processing and production. Fuel Processing Technology, Vol 86, 2005. [5] M. Canacki. potential of restaurant waste lipids as biodiesel feedstocks. Bioresource Technology, vol 98, 2007. [6] ASSOCIAÇÃO BRASILEIRA DE NORMAS TÉCNICAS (2009). NBR ISO 14040 Gestão ambiental – Avaliação do ciclo de vida – Princípios e estrutura. Brasil: ABNT. Agosto. 21p. [7] ASSOCIAÇÃO BRASILEIRA DE NORMAS TÉCNICAS (2009). NBR ISO 14040 Gestão ambiental – Avaliação do ciclo de vida – Requisitos e orientações. Brasil: ABNT. Agosto. 46p.
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