Exergy Analysis of Biomass-Based Ethyl Levulinate Fuel for Whole Life Cycle

Abstract

Hydrolysis of agricultural residues into ester fuels is an important way to alleviate energy shortage and reduce greenhouse gas emissions, which is in accord with the major demand of sustainable energy development strategy. Based on the production and application of biomass-based ester fuel, this paper analyzed the growth, collection, pretreatment, hydrolysis and esterification of bagasse, transportation and distribution of fuel, and the vehicle use of fuel, make clear the exergy efficiency and distribution law of pollutant exergy consumption over the whole life cycle. The results are as follows: the overall exergy efficiency of the system for preparing ethyl levulinate (EL) by hydrolysis of bagasse is 64%. The exergy consumption proportion of CO2 is the largest (72%), the second is SO2 (7%) in the distribution of exergy consumption of different emissions in the whole life cycle. The exergy consumption of VOC, CO, NOx and PM10 in gas pollutants is less than 2%, while the exergy consumption of N2O, CH4 and HC is between 2% and 4%. The exergy consumption of industrial sewage accounted for the lowest of 1%, while the exergy consumption of agricultural sewage accounted for 5%. The exergy consumption of CO2 in the whole system is much higher than that of the sum of other pollutants. Based on the results of exergy analysis, the preparation of biomass-based EL can be optimized. It is suggested to improve the environmental index of the whole life cycle of the system, reduce the dependence on pesticides and fertilizers in the process of crop planting, reduce the electricity consumption in the process of ester fuel production as much as possible, and increase the proportion of clean power generation using renewable energy, so as to control the greenhouse gas emissions at the source.