尿素预处理对玉米秸秆厌氧发酵产沼气特性影响及动力学分析

EFFECT OF UREA PRETERATMENT ON BIOGAS PTODUCTION CHARACTERISTICS OF CORN STRAW ANAREOBIC DIGESTION AND ITS KINETICS

针对玉米秸秆厌氧发酵产沼气过程中难降解问题,选用尿素对玉米秸秆进行预处理,并进行批次厌氧发酵产沼气试验研究。结果表明:经过45 d厌氧发酵,累积产气量最高为757.83 mL/g VS,最低为588.64 mL/g VS,厌氧发酵进行到25 d时达到45 d累积产气量的85%。分析联合预处理对累积沼气产气量影响得出,尿素质量浓度、预处理时间和玉米秸秆粒径3个因素对累积沼气产气量的影响程度是:玉米秸秆粒径>尿素质量浓度>预处理时间。通过2种动力学模型分析产气规律,对比模型的检验参数,得出Cone模型拟合预处理玉米秸秆厌氧发酵产气规律的适合度较高。

The study aims to solve the problem of refractory degradation in the process of biogas production from corn straw anaerobic digestion. After pretreating corn straws with urea,the biogas anaerobic digestion experiments were conducted. The results showed that after 45 days of anaerobic digestion,the maximum cumulative biogas yield was 757.83 mL/(g VS),and the lowest one was 588.64 mL/(g VS). At 25 days,the cumulative biogas yield reached 85% of 45 days’ total cumulative biogas yield. The analysis of the influence of pretreatment conditions on the biogas yield show that the effects of urea concentration,pretreatment time and corn straw particle size on cumulative biogas yield are corn straw size > urea mass concentration > pretreatment time. Two kinetic models are used to analyze the biogas production law,and the test parameters of the model are compared. It shows that Cone model is more suitable for pretreatment of corn straw anaerobic digestion for biogas production.