渗滤与间歇高温液态水预处理甘蔗渣的对比研究

COMPARISON OF LIQUID HOT WATER PRETREATMENT WITH FLOW-THROUGH AND BATCH REACTOR FOR SUGARCANE BAGASSE

以甘蔗渣为原料,采用自主搭建的连续渗滤试验台,考察反应温度、反应时间、反应液流量对甘蔗渣水解情况的影响。实验发现水解液中木聚糖主要以低聚木糖的形式存在,其所占总木糖的比例主要与反应温度和反应液流量相关,高处理温度、低流量易于生成木糖并进而生成副产物,说明木聚糖在高温液态水中的水解路径为:木聚糖—低聚木糖—木糖—糠醛等。通过实验确定180℃是最合适的反应温度,反应液流量为30 m L/min,15 min获得具有4.17 g/L总木糖的水解液,此时总木糖收率可达93.95%。与间歇搅拌反应形式中的水解情况进行对比分析发现,在相同处理效果的前提下连续渗滤反应形式耗水量更大,但渗滤反应形式可获得更高的木糖收率,残渣酶解率、总糖收率均高于间歇法,副产物生成量也低于间歇反应形式。

Sugarcane bagasse （SCB） was hydrolyzed with liquid hot water （LHW） in a flow-through reactor and the influence of reaction temperature, residence time, and flow rate was investigated. Xylo-oligosaccharides are found to be the main component of dissolved xylan in the hydrolyzate, the ratio of xylose and xylo-oligosaccharides mainly depends on the reaction condition, severe condition usually enhanced the solubilization of xylan and got more xylose and byproducts, indicated that the hydrolysis of xylan follows the order of xylan-xylo-oligosaccharides-xylose-decomposition products. 180 ℃ was found to be the optimal temperature for the LHW pretreatment, the condition of 30 mL/min, 15 min had a total xylose yield of 93.95%, with a total xylose concentration of 4.17 g/L. Compared with the batch reactor, water consumption of flow-through reactor is higher than that of batch reactor for a same xylose yield, and flow-through reactor can get a more satisfactory xylose yield and total sugar yield with less by-products produced.