Study On Evaluation System Of Life Cycle Analysis And Impact Of Land Use Change Of Biomass Based Ester Fuel

In the paper,the biomass based ethyl levulinate（hereinafter as the “ester fuel”）was taken as the research object,the whole life cycle analysis of energy efficiency and environment system,economy analysis model and land use change analysis framework were built and investigated by considering the input of material,land,capital and energy.Based on the whole life cycle analysis method and comprehensive energy efficiency and environmental analysis indicators,the whole life cycle energy efficiency and environmental analysis of biomass based ester fuels were carried out,the energy consumption and environmental emission of each section in the conversion process of ester fuel using corn stalk were studied.The exergy consumption distribution of the whole life cycle and exergy consumption distribution of different pollutant types were analyzed.The economic analysis model was established via static and dynamic technical and economic indicators,and the life cycle of biomass ester fuel was analyzed with different conversion scales.Taking biomass based ester fuel as an example,the analysis framework of indirect land use change（ILUC）was established,and carbon sequestration and impact of land use change were analyzed.The results are as followings:（1）Considering the growth demand,environmental benefits,economic value and utilization scale of grain and straw,and combined with the parameters such as grain grass ratio and price ratio,a more scientific division proportion was calculated.In the emission analysis of the raw material stage of the whole life cycle system of corn stalk based ester fuel,89.2% of the emissions were divided to corn,while corn stalk accounts for 10.8%.In the whole life cycle analysis,the hydrolysis and esterification stage of biomass ester fuel required the most energy consumption,which was far more than the total energy consumption of other stages;The positive emission of greenhouse gases（GHG）in the hydrolysis and esterification process of the whole system was the most,followed by the ester fuel utilization process.The total standard gas emissions of hydrolysis esterification and ester fuel utilization were in the top two of the whole system.The emission of sulfur dioxide in hydrolysis esterification stage was much higher than that of other standard gases,which was mainly due to the coal-fired emission caused by power consumption in power plant.The overall exergy efficiency of the pretreatment system for production of ester fuel by hydrolysis and esterification of corn stalk was 62%,and the exergy loss of dryer and heat exchanger was large.Improving the exergy efficiency of heat exchanger was the key to improve the quality of energy utilization.The exergy consumption distribution of different emissions in the whole life cycle of ester fuel fuel prepared from corn stalk shown that the proportion of CO2 exergy consumption was the largest,which was 72%.The second was the exergy consumption of SO₂,which was 7%.The exergy consumption of VOC,CO,NO_x and PM₁₀ in gas pollutants was less than 2%,while the exergy consumption of N₂ O,CH₄ and HC accounted for 2-4%.The proportion of CO2 exergy consumption in the whole system was much higher than the sum of other pollutants,which was mainly due to the large amount of electric exergy consumption in the production of ester fuels.With the increase of renewable electricity,the exergyc onsumption of CO2 will be gradually decreased.（2）The production cost of ester fuel from straw varied in different stages.In the stages of collection,transportation and pretreatment,the cost of raw material pretreatment accounts for 90% of the total cost of raw material stage.The fixed investment cost can be understood in the aspects of biomass straw pretreatment,transformation and by-product post-treatment,in which the investment in fixed assets in the pretreatment stage of raw materials accounts for a large proportion.The investment cost of fixed assets in the core transformation stage was closely related to the production scale and straw resources.The process cost of biomass ester fuel was mainly the cost of raw materials.In biomass based ester fuel system,the price of ester fuel has the greatest impact on net present value,internal rate of return and investment payback period,followed by energy cost.The internal rate of return of the pilot scale biomass ester fuel production system was 12.21%,and the investment payback period was 8.35 years.The internal rate of return of the large-scale production system was 35.08%and the investment payback period was 5.32 years.The large-scale production system improved the economic benefits by increasing the hydrolysis and esterification efficiency and reducing the production cost.Blended fuel EL2.5 and EL5 of ester fuel adding to diesel have good combustion characteristics compared with pure diesel,and the price increased by2.11% and 4.11% compared with pure diesel.The use of biomass based ester fuel blended fuel into diesel has a good application prospect.（3）Combined with the research status of land use change caused by biomass fuel in Europe,Brazil and other countries and regions,the evaluation methods of land use change were analyzed,and the framework of indirect land use change according to the general situation of energy utilization and biomass resources in China were established.The research direction of land use change caused by biomass fuel production and utilization in China was put forward.Taking biomass based ester fuels as an example,indirect land use change was studied.Through statistical analysis,the planting area,agricultural product yield,land use change and types of agricultural and forestry crops in China in recent years were analyzed.The utilization of residues of corn,rice and wheat was the main way of carbon sequestration,which was closely related to soil carbon sequestration.In the whole life cycle of the produciton of ester fuel by hydrolysis of corn stalk,the carbon fixation,carbon emission and carbon balance were realized,and the impact of indirect land use change caused by energy crop planting was avoided.Finally,the direct and indirect land use change and estimation methods were put forward,and the policy implementation suggestions of land use change were raised,so as to provide reference for the estimation of land use change from biomass fuel in China.