The biorefinery concept is attractive. Increasing international concerns over issuessuch as climate change have led to political as well as social pressures for a shift fromfossil fuels to renewable resources and biomass is one abundant renewable resource.Biomass has the potential of supplying many of the fuels and chemicals which arecurrently dependent on petroleum. Much development is still needed in the field ofbiorefineries and a systematic approach to evaluate and compare process technologiesand to suggest optimizations seems necessary.The objective of this thesis is to develop entropy analysis as a possible evaluation toolfor optimization of biorefinery processes. This is a new application of entropyanalysis which is rarely discussed in the literature. The scientific basis of the entropyanalysis is described and the proposed methodology is explained. The position ofentropy analysis among other system analysis tools such as exergy analysis and lifecycle assessment is discussed along with entropy analysis earlier applications.A case study is introduced which is the IBUS (Integrated Biomass Utilization System)project in Denmark. The idea in IBUS is to integrate the biomass plant with a powerplant to utilize the surplus steam from the power plant for the internal use of thebiorefinery. The suggested method of entropy analysis is applied to this case study tocompare different processes for production of ethanol along with solid biofuel andanimal feed from Danish wheat straw. The evaluation is a gate to gate analysis inwhich production of energy carriers are also included in addition to biorefining ofwheat straw. A parallel life cycle assessment study with equivalent system boundariesis also carried out to compare the results with a conventional environmental systemsanalysis method.The results from the entropy analysis of the IBUS case study show that fermentationof C5 and C6 sugars by yeast is the most efficient process thermodynamically whilefermentation of only C6 sugars by yeast is the least efficient among the three casesstudied. Integration of the biorefinery with a coal fired CHP plant is identified as awise choice by the results of the entropy analysis method.For the IBUS process alternatives investigated in this study, the entropy results andthe LCA results (aggregated environmental load) are in correlation; entropy results areconsistent with weighting results based on two different weighting methods namelyEco indicator 99 and EPS 2000. Entropy generation is also in correlation withproduction cost for the processes analyzed in this evaluation. Another observation isthat cooling in the biorefining process contributes highly in the generation of entropy.This potential improvement option is not surfaced by the LCA conducted.The potential for further investigation and development of the tool is recognizedreflecting on some interesting observations in the results. Improvement of the tool ishighly possible for example by supplementing other implications of entropy inprocess design such as "waste potential entropy" concept which is developed as aneco-toxicity measure. / Uppsatsnivå: D
| Identifer | oai:union.ndltd.org:UPSALLA1/oai:DiVA.org:hb-18679 |
| Date | January 2007 |
| Creators | Samiei, Kasra |
| Publisher | Högskolan i Borås, Institutionen Ingenjörshögskolan, University of Borås/School of Engineering |
| Source Sets | DiVA Archive at Upsalla University |
| Language | English |
| Detected Language | English |
| Type | Student thesis, info:eu-repo/semantics/bachelorThesis, text |
| Format | application/pdf |
| Rights | info:eu-repo/semantics/openAccess |
| Relation | Magisteruppsats, |
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