| The energy shortage has become a global challenge with the increasing energy demand. While fuel ethanol can improves the atmospheric environment as a kind of green and renewable energy and has the potential to become an ideal substitute for fossil fuels. Lignocellulose is a promising resource for bioethanol production due to its abundance, renewable, and low cost. However there are a lot of deficiencies in the lignocellulosic fuel ethanol production process, for example, the technology is far from maturity and the production cost of cellulosic ethanol is still higher than that of grain ethanol, which impede the industrialization of cellulosic ethanol.In this research, corn stover is choosed as the material for cellulosic ethanol production according to the local crops in Jilin Province. This research focus on the designing of process model, application of heat integration technology, technical and economic analysis in order to provide an available process as well as evaluation for the lignocellulosic ethanol production. It can be used in the future industrial plants for the process design, operation optimization and economic evaluation. The thesis mainly includes the following three parts:(1) A cellulosic ethanol production process based on corn stover was established and simulated. Pretreatment step have been identified as technological bottleneck for industrialization of cellulosic ethanol technology. The technological process of several typical pretreatment methods are reviewed and compared in terms of advantages and disadvantages, economics among those methods are performed and compared. As a result acid pretreatment method is chose and ammonia as a substitute of Ca(OH)2in detoxification section which simplify the process. Then estimation of physical property for biomass components is conducted with process simulation software Aspen Plus. Finally, cellulosic ethanol production with annual capacity of30000tons are designed in Aspen Plus platform. The simulating results show the annual consumption of corn stover is144000tons, water consumption and wastewater remission are5.5and7.7tons per ton of ethanol respectively.(2) Heat integration of whole process and process analysis are conducted by the energy analysis software Aspen Energy Analyzer. The results show that the energy consumption decreases from77887.2kW to52510kW after heat integration and energy saving potential is32.6%. The impact of the total solids content (mass fraction10%-34%) on the water and energy consumption of whole process is examined The result shows that the water consumption has been reduced with the increase of total solids content and energy consumption is declined and then rose.(3) A economic analysis for above cellulosic ethanol production process are conducted. Firstly, total investment estimation and total cost of production are estimated. Then financial calculation is conducted based on static analysis, dynamic analysis, profit and loss balance analysis. In additional, sensitivity analysis of profits was carried out focused on the key factor of income. The results show that the total project investment cost is RMB475.5million RMB, total production cost is RMB6987.4/tons Eth. Financial analysis shows that this design of lignocellulosic ethanol production process based on dilute acid pretreatment is financial feasible. Sensitivity analysis shows that the net profit is zero when the corn stover cost exceed RMB651.6/tons Eth and ethanol price reduced to RMB4.3/L. |
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