基于不同时间碱液预处理条件下厌氧发酵物料的转化

碱液预处理法操作简便、木质素去除效果显著,是目前较为常用和有效的秸秆预处理方法。本研究以玉米秸秆为原料,采用较低浓度碱液(1.2 %)预处理,分别测量预处理2 d、4 d、6 d、8 d、10 d后的原料中纤维素、半纤维素和木质素的变化水平,选择COD、产甲烷率、产气率等指标对比分析不同预处理时间对于发酵产气率的影响及物料平衡情况,为探求预处理和厌氧发酵过程中物料转化原理、碱液成分分析以及碱液回收利用等研究方向提供参考依据。结果表明,预处理2 d的条件下,破坏木质素纤维结构所析出的半纤维素占比最高为11.93 %,半纤维素得到最大程度解离是高产气率的重要原因之一,同时该条件下COD浓度最高达到17.93 g/L,秸秆损耗率最低,仅占15.24 %。厌氧发酵实验中,预处理2 d后的原料产气率最高为49.43 %,能够满足在高产气率的前提下,实现缩短预处理时间和提高产气效率的双重效果。

Material Conversion Studies of Anaerobic Fermentation on Alkaline Pretreatment in Different Time

The alkaline pretreatment method is easy to operate and has remarkable removal efficiency of lignin. It is a common and effective pretreatment method of straw, nowadays. In this study, corn straw was pretreated with low concentration of alkaline solution (1.2 %) to measure the change of cellulose, hemicellulose and lignin in the raw materials after pretreatment for 2, 4, 6, 8, and 10 days, respectively. The influence of different pretreatment time on fermentation gas production rate and material balance were compared and analyzed by the change of COD, methane production rate and gas production rate. This study provided reference for exploring material transformation principle in anaerobic fermentation process, the analysis of alkaline component and the recovery and utilization of alkaline after pretreatment. The results showed that the highest proportion of hemicellulose was 11.93 % after pretreatment for 2 days. The maximum dissociation of hemicellulose was an important reason for high gas production rate. The highest COD concentration was up to 17.93 g/L and the lowest straw loss rate was only 15.24 % in the same time. In the experiment of anaerobic fermentation, the highest gas production rate of raw material after pretreatment for 2 days is 48.50 %, which own dual effects of shortening pretreatment time and improving gas production efficiency under the premise of high gas production.