温和水热预处理促进秸秆产沼气的条件优化研究

以水稻秸秆为原料，在前期单因素试验基础上，通过正交试验研究不同水热预处理条件对稻秸理化特性及产沼气效果的影响.结果表明，预浸时间、初始含水率和热处理时间3个因素对稻秸厌氧发酵20d累积TS产气率的影响程度各不相同，各因素对厌氧发酵累积TS产气率的影响大小顺序为初始含水率 >预浸时间 >热处理时间；得出的最佳水热预处理条件为：初始含水率为55%，预浸时间为2h，热处理时间为6h；与处理CK相比，最佳预处理条件下稻秸20d容积产气率提高29.79%，产气量达总产气量60%和80%时间可提前5d；结合预处理前后稻秸理化特性变化规律分析，表明温和水热预处理促进了纤维素和半纤维素的降解溶出，并促使其更多转化为挥发性脂肪酸（VFA），从而有利于稻秸快速产沼气.

Optimization of conditions for promoting biogas production with hydrothermal pretreatment for straw

Effects of physic-chemical properties and biogas production were studied through orthogonal experiment with different hydrothermal pretreatment conditions, in the basis of the preliminary optimization of single factor test and with rice straw as raw material. The results showed that there has different impact on the 20days cumulative biogas production of anaerobic fermentation with rice straw for three factors, which including pre-leaching time and content of initial moisture with materials and heating time. The order of the effect on the cumulative TS yield of anaerobic fermentation for each factor is that content of initial moisture with materials > pre-leaching time > heating time; the condition that the initial water content of 55%, leaching time of two hours, the heating time of six hours were considered as the best condition. The 20days cumulative biogas production with rice straw under this optimum pretreatment conditions is increased by 29.79%, the time of biogas production reached 60% and 80% of the total gas production can be reduced five days compared with CK. And the result showed that the mild hydrothermal pretreatment promoting the degradation of cellulose and hemi-cellulose and make it more converted to volatile fatty acids (VFA), which is conducive to rapid biogas production of rice straw, combined with analysis of the changes of physical and chemical properties. The mild hydrothermal pretreatment process parameters that provided technical support and theoretical basis for the operation of straw biogas project were obtained from this experiment.