|
The comprehensive utilization of biomass energy and energy conservation for the new study is one of the key development areas of the Jiangxi provincial government’s "six-ones" project.Efficient use of storage in these plants not only for the energy straw in part alleviate the energy shortage problem in China, but also for environmental protection in the vast rural areas of great significance. The effective separation of the main components of straw and its hydrolyzate fermentation to ethanol was taken positive efforts to explore, the main contents are as follows:Firstly, The new utilization plan of straw have been proposed according to the main components of rice straw with different chemical properties, step by step, to separate effectively the main components, based on dilute acid hydrolysis pre-treatment.Secondly, after a series of experiments, the optimum conditions of acid hydrolysis, which 0.5% HCl+0.5% H2SO4, solid-liquid ratio of 1:5,100℃. Studies have shown that this condition can guarantee the maximum level of hemicellulose to dissolution, but also to ensure the least amount of fermentation inhibitors generated.Thirdly, acid catalyzed hydrolysis of rice straw is off most of the hemicellulose component and form the xylose and glucose hydrolysates by hydrolysis; also, straw composition of cellulose is more exposed than before. However, in dilute acid hydrolysis process of rice straw, lignin has little changes. In view of it, the delignification reaction is performed, and the resulting water-soluble lignin can be used as tertiary recovery agent. After acid catalyzed hydrolysis and lignin sulfomethylated, the remains are relatively pure cellulose. It can be effectively carried out its enzymatic hydrolysis, the enzymatic hydrolysis Efficiency of up to 93%.Fourthly, for the main components of the rice straw hydrolysates produced by acid hydrolysis are xylose and glucose. the traditional fermentation of glucose to ethanol can not apply on the fermentation of xylose. In this work, a Candida shehatae is selected to use in ethanol fermentation of xylose and glucose. Studies showed that pH=6.6, fermentation time 80h,120r/min are optimal conditions, and the ethanol production rate reaches to 39%, a higher level in similar studies.
|