pH值对沼气产气量的影响

Research on the Effect of pH for Biogas Production

[目的]探讨发酵条件对产沼气的影响。[方法]以新鲜猪粪为原料,采用批量进料的方法,研究了7个处理（pH值分别为5.5、6.0、6.5、7.0、7.5、8.0、8.5）对厌氧发酵产气量、产气特性的影响。[结果]不同pH处理发酵都能启动。以pH值6.5启动最快,其次是7.0,其余pH处理启动较慢。各处理的pH值上升到6.5的时间为11 d（pH值7.0）1、2 d（pH值6.5）3、0 d（pH值7.5）3、2 d（pH值6.0）。pH值7.0和pH值6.5的60 d总产气量最高,pH值6.0次之,pH值5.5最低。pH值7.0处理的CH4含量最高,达78.0%,与其他处理差异极显著;pH值6.5处理的CH4含量最大为62.0%;其余各处理CH4含量50.0%左右,差异不显著。[结论]发酵体系的pH值为6.5～7.0,可促进厌氧发酵的启动,提高产沼气的质量。

[Objective] The study was to explore the influence of ferment condition on biogas production.[Method] With fresh pig dung as material,7 treatments with pH value of 5.5,6.0,6.5,7.0,7.5,8.0 and 8.5 were designed to study their influence on the yield and character of biogas through anaerobic fermentation by batch feed-in method.[Result] The treatments with different pH could all start the process of fermentation.The treatment with pH 6.5 started most fast,and the second was that of ph 7.0,the treatments with other pH started slowly.The times that the pH（7.0,6.5,7.5,6.0） in each treatment was rose to 6.5 were 11,12,30,32 d resp..The total biogas production at 60 day in the treatment with pH 7.0 was most and that with pH 6.0 was secondary and that with pH 5.5 was lowest.The content of CH4 in the treatment with pH 7.0 was highest（78.0%） and was significantly different from that in other treatments.The biggest content of CH4 in the treatment with pH 6.5 was 62.0%.The content of CH4 in other treatments was about 5 0.0% and had no obviously different from CK.[Conclusion] The pH 6.5-7.0 in fermentation system could promote to start fermentation and increase the quality of biogas.