Research On Key Technologies For Preparing Bio-polyols From Straw Cellulose

Biological polyol,which was refers to the ethylene glycol,propylene glycol,glycerin and all kinds of butyl glycol,etc.Those glycol was a indispensable raw material in chemical production,which mainly were produced by hydration method using oil,ethylene oxide and propylene at present.As the oil energy crisis became intentinonally,the subsequent product production became more and more difficult.Adopting the biological chemical method to prepare biological polyols by using straw fiber is a new way to transform agricultural waste resources.This study optimized those links of straw sugar transformed polyol,and under the improvement of straw sugar transform filter,preparation technologies and key technologies of industrialization were studied to realize the industrialization.Stalks of sugar production technology was optimized.On this part of the test the effects of four different pretreatment conditions on the saccharification were compared,and the optimum condition were as follows:190?,5% sulfuric acid,3min with1:1 presoak solid-liquid ratio.After processed,the content of sugar and xylose up to 8.03 g/L and 3.02 g/L respectively.The optimum hydrolysis conditions of saccharifying enzyme was optimized by single factor experiment,which were as follows:50?,pH4.8,saccharifying enzyme 7FPU.Through single factor and orthogonal test,the optimum conditions of high pressure hydrocracking straw sugar to make biological polyols were as follows :120min,11 MPa,230?,4% alkaline,under which conditions the rate of conversion was 81.61%.After through rectifying column,the content of propylene glycol and ethylene could reach more than 99%,and the moisture content was below 0.5%.Considering the cost problem,while the content of all kinds of butyl glycol content were less,so we took no account of separating them.Enlarging producing,the pilot plant scale is 300 t/a,after more than 20 batchtrial-produce,those products could meet national standards.Through the design of key technologies in the process of industrialization,including material balance and process flow diagram,the construction scale of straw into biological polyol production line was feasible.