温度对秸秆厌氧消化产气量及发酵周期影响的研究

Effect of Temperature on Biogas Production and Fermentation Period Length from the Anaerobic Digestion of Crop Residue

温度是影响沼气产气效率和发酵周期的主要生态因子,探索农作物秸秆产气量和发酵周期与发酵温度之间的关系,是解决农村户用沼气原料选择、确定最佳发酵温度和提高作物秸秆资源化利用的效率的关键;本试验通过自行研究设计的可控性恒温发酵装置,以麦秆、稻秆和玉米秆作为发酵原料,以常温厌氧发酵池的底物为接种物,在总固体(TS)质量分数为8%的条件下进行批量试验,在25～40℃温度范围内,每5℃设一个温度梯度,研究了不同发酵温度对产气速率、产气量及发酵时间的影响,并用SAS软件对各因素进行多元回归分析,建立了回归方程,得出各因素的最优值。结果表明,在一定的温度范围内,3种秸秆厌氧发酵的产气速率的峰值出现的时间和发酵周期是随着温度的升高而缩短,其峰值和产气量是随温度的升高而增加。

Temperature is one of the main factors influencing fermentation period length and biogas production efficiency from the anaerobic digestion of crop residue. An improved understanding of the influence of temperature on the anaerobic digestion process is important for making recommendations regarding the choice of fermentation material and digestion conditions for biogas production in rural areas. The overall effect would be an increase in the utilization efficiency of crop residue. The experiment was to study the influence of temperature on the biogas yield, biogas production rate, and the length of the fermentation period from three types of crop residue： wheat, rice, and corn. Anaerobic digestion tests were conducted in a controllable constant temperature fermentation device that we designed. A series of experiments were conducted with temperatures increasing in increments of 5 ℃ from 25-40 ℃. The total solid （TS） of the fermentation material was 8% wt. The substrate was inoculated with material from a household biogas pool. Multiple regression analysis of the data was conducted and regression equations were established using SAS software. Based on these results, optimal values for temperature and digestion time were determined to maximize biogas yield per unit dry matter. The results showed that the time to get maximum biogas production rate and the overall length of the fermentation period were shortened as temperature increased within a certain range for all three types of straw. In addition, maximum biogas production rate and biogas yield increased with temperature increasing.