玉米秸秆与猪粪混合厌氧发酵产沼气工艺优化

摘要

Rural household biogas fermentation materials are mainly manure in China. Biogas plants cannot run steadily due to shortage of manure. Straw are rich in China, and anaerobic fermentation with mixed materials of corn straw and pig manure can be used to supplement fermentation materials. Thus it is important to study on optimization of mixed material of corn straw and pig manure. In this study, we conducted the experiments through the earlier single factor test. Quadratic regression orthogonal rotating combination design was adopted and the whole gas production was taken as the response value. Effects of four factors on anaerobic fermentation were analyzed. These four factors included ratio of corn straw and pig manure, temperature, pH, and ratio of inoculum and quality of raw fermentation material. The mathematical model for mixed fermentation of corn straw and pig manure was developed. The regression equation was optimized and analyzed when the optimum conditions and interactive effects were exposed. The optimum conditions for mixed-fermentation were determined as follows:the ratio of corn straw to pig manure was 1, pH value was 7.5, the ratio of inoculum volume and quality of raw fermentation material was 50%, the temperature was 30℃, and biogas production obtained is 18.51 L. The order of the influence of four factors on mixed-fermentation of corn straw and pig manure was:ratio of corn straw and pig manure, temperature, ratio of corn straw and pig manure, and pH value. Comparing with interactive effects of corn straw and pig manure raw material ratio, pH, raw material ratio and temperature on biogas yield including corn straw and pig manure raw material ratio and inoculum volume, pH and inoculum volume, pH and temperature, the effect of inoculum volume and temperature was not significant. During the optimum biogas production process in this experiment, the relative error of gas production between model prediction and experiment measurement was less than 5%. This study is expected to provide references for improving biogas production and fermentation efficiency of mixed material of corn straw and pig manure.%该研究针对农村户用沼气发酵中粪便类发酵原料不足、影响沼气池利用率的问题，为弥补沼气发酵原料单一及不足，将秸秆、粪便混合作为发酵原料，对秸秆粪便混合原料厌氧发酵产沼气的工艺条件进行优化研究，旨在为农村户用沼气工程的健康、稳定运行提供一定的科学依据。在前期单因素试验的基础上，采用二次回归正交旋转组合设计，以产气量为响应值，研究玉米秸秆与猪粪质量比、温度、pH 值、接种物质量分数4个因素对玉米秸秆与猪粪混合厌氧发酵的影响，得出产气数学模型，并对数学模型进行了理论分析。通过上述试验研究，得到最佳工艺条件为：玉米秸秆与猪粪质量比为1∶1、pH值为7.5、接种物质量分数为50%、温度30℃，预测产气量为18.51 L。4因素影响主次顺序依次为原料玉米秸秆与猪粪质量比、温度、接种物质量分数、pH值；通过验证分析，模型预测值与试验值之间相对误差小于5%，方差分析不显著，模型拟合较好，为提高粪便秸秆混合原料发酵产气量和提高发酵效率提供参考。