Study On The Technology Of Fermenting Rapeseed Straw To Produce Bioethanol

Rape is an important edible oil crop in China, accounting for 25.3% of the world's rape planting area, the yield of rape straw is about 1.8×107-2.04×107t/a.The rape straw of the comprehensive utilization and the depth development is restricted because the rape straw contains a lot of cellulose and hemicellulose. At present, the treatment methods of rape straw are mainly in the field of burning or natural degradation, which not only waste the organic resources, but also pollute the environment. If it is converted into liquid fuel such as alcohol, not only can ease the energy crisis, but also provide a guarantee for the sustainable development of society.In order to take full advantage of rape straw resources and find the suitable production process of rape straw and alcohol.Acid pretreatment, alkali pretreatment and microwave pretreatment technology of rape straw were studied in this paper. On the basis of this, the effects of microwave pretreatment on the yield of sugar and the yield of ethanol were studied, and the optimized conditions were optimized by using response surface method.The results were showed as follows:1?The effects of acid pretreatment, alkali pretreatment and microwave pretreatment on cellulose degradation rate and yield of sugar of rape straw were studied with the degradation rate and yield of sugar as index by using single-factor experiment.The results showed that:(1) The process conditions of acid pretreatment were:sulfuric acid concentration 1.5%, pretreatment of 1.5h under constant temperature at 110?, the cellulose degradation rate and the yield of sugar were 94.5% and 34.73% respectively under the suitable conditions for enzymatic hydrolysis.(2) The process conditions of alkali pretreatment were:Sodium? hydroxide concentration 6%, pretreatment of 18h under constant temperature at 60?, the cellulose degradation rate and the yield of sugar were 88.93% and 24.59% under the suitable conditions for enzymatic hydrolysis. (3) The process conditions of microwave pretreatment were:microwave irradiation power 700W, irradiation treatment 6min, The cellulose degradation rate and the yield of sugar were 93.76% and 37.68% respectively under the suitable conditions for enzymatic hydrolysis.2?The effects of treatment conditions such as microwave power,pretreatment time,the ratio of water to solid,pH,enzyme concentration and enzymatic hydrolysis time on the yield of sugar and alcohol were studied by using single factor test with rape straw as material.Then the interactional effects of microwave treatment time,ratio of water to solid,pH and enzyme concentration on the yield of sugar and alcohol were evaluated by using a response surface method,based on above test results.Date were analyzed with Design Expert 8.0.5b software.The results showed that good quadratic polynomial models of conditions of cellulose conversion were obtained,the model of yield of sugar and alcohol are extremely significant (p<0.0001) and there were no lack of fit.The optimum conditions of producing bio-ethanol from rape straw cellulose conversion were as follows ?microwave treatment time 7min,ratio of water to solid 24.15,pH value 5.95, enzyme concentration 6640IU/g.Under these conditions,the yield of sugar and alcohol was 25.3394% and 9.7901%.