Building Cellulosic Ethanol Conversion Evaluation System And Its Exploration On Straw Particles

Currently, the development of cellulosic ethanol is on the stage of research and demonstration plant. Raw material supply system and conversion technology are the bottlenecks for hindering its industrialization. In China, crop straw is the main raw material for producing cellulosic ethanol and we should build related assessment system to evaluate and analysis the raw materials.There are two methods to produce cellulosic ethanol, hydrolysis method and the thermochemical method. Hydrolysis method is to transfer the polysaccharide of the raw materials into ethanol and the thermochemical method gasificates the raw materials into synthesis gas and transfer them into ethanol. Curretly, hydrolysis is widely used. Based on the ways of chemical technological economic research, this article tries to build cellulosic ethanol conversion assessment system by using evaluation methods such as Delphi method, frequency analysis method and analytic hierarchy process, etc., to build the assessment indexes include three first-class indexes, such as technological index, etc; seven second-class indexes, such as raw materials composition; twenty-two third-class indexes, such as content of cellulose, scale of conversion device, utilization rate of fuel, cost of raw material, target price of cellulosic ethanol and carbon dioxide emission, etc. And then calculate the weight of each assessment index, that is cellulosic ethanol conversion (w=0.1994), scale of conversion device (w=0.1040), cost of cellulosic enzyme (w=0.0595), content of cellulose (w=0.0581), cost of raw materials (w=0.0510), carbon dioxide emission (w=0.0448) and content of semi-cellulose (w=0.0434), which build the main assessment index system. Score the crop straws such as maize straw, corn straw and sugar grass straw and confirm the optimum conversion method to every raw material. Besides that, the comprehensive score of raw materials is:maize straw (0.1551), corn straw (0.2034) and sugar grass straw (0.1416), and corn straw’ score is higher than the other two straws then this article focuses on the cellulosic ethanol conversion of corn straws.In the respect of corn straw’s storage and transportation system, the volume of corn straw is so large that more spaces and transport vehicles are needed. What’s more, raw materials should have relatively higher requirement, such as content of water should be controlled with20%, without clay and no enzyme change. So there exist problems of every stage as collection, storage and transportation. Chapter4puts forward a new idea about making the corn straws into particles. Chapter5analyses the corn straw particles and come to the conclude that the particles are is technically feasible, as the cellulosic content of particles is38.75%, which doesn’t make big difference with straw corn (39.41%). Provide the fittest way for corn particles producing cellulosic ethanol, making the raw materials into particles can also solve the problems of exist straw storage and transportation system in this way, which provides reflection for industrialization of cellulosic ethanol.