Study On Producing Fiber Ethanol With Lignocellulosic By Simultaneous Saccharification & Fermentation And Ethanol Dehydration

Now fuel ethanol has got more and more attention,which is widely used as the substitute of fossil fuel.The development of the second generation fuel ethanol made from cellulose is one important way to develop non-grain ethanol.In this paper cellulose raw materials were the experimental materials, components and crystallization structures of three kinds of cellulose raw material were analyzed and evaluated,the technology and process of translating furfural residue fiber into ethanol by simultaneous saccharification and fermentation were investigated and optimized.Besides.the yeast-activated technolog and the optimal condition of producing anhydrous ethanol by pervaporation were studied preliminarily.The components and crystallization structures of cellulose raw material:the percent of cellulose in furfural residue is 42.23%,bamboo 53.49%,Caragana 43.97%;the data of crystallinity is that:furfural residue 49.01%,in bamboo 58.76%,in caragana 57.43%.The crystallinity of furfural residue is the lowest for complex mesh structure among cellulose,hemicellulose and lignin are damaged.As a result, the saccharification of cellulose became easy.Therefore.the furfural residue is considered as the ideal raw material of fiber ethanol.The experimental device for ethanol dehydration by pervaporation (membrane area is 0.2m~2 ) was also stablished.Furfural residue pretreated by overliming was fermented to ethanol by batch simultaneous saccharification and fermentation(SSF) in this paper.The optimal combination of factors(reaction temperature,solution pH value,loading of both cellulase and tween-20) affecting the conversion of pretreated furfural residue to ethanol was found by orthogonal design experiment.The SSF of furfural residue was experimented in 5L fermentor,and the data of different phases were analyzed simultaneously.The optimal conditions were as follow:38℃of reacton temperature,4.2 of pH value, cellulase 20 FPU/(g cellulose),0.15%of tween-20 and 10%inoculum solution.The ethanol recovery up to 72.33%(vs theory data) was obtained in 5L fermentor.The simultaneous analysis result indicated that the highest ethanol conversion rate appeared at 27 h,which is much less than that of other cellulose material.The cellulose content and crystallinity index of fermented furfural residue decreased as the SSF proceeded,and the average dimension of cellulose crystallite had decreased during enzymatic hydrolysis.The study on technology of ethanol dehydration by pervaporation showed that separation factor and permeation flux increased with temperature enhanced.When water content increased,the separation factor declined and permeation flux increased.Once flow changed,separation factor and permeation flux increased with flow enhanced.At 85℃,320L/h,membrane area of 0.2m~2,99.81%anhydrous ethanol can be got from 95.38%ethanol with cycle dehydration by pervaporation for 9 hours.