秸秆中温厌氧发酵产沼气研究

Study on Biogas Produced by Straw in Medium Temperature Anaerobic Fermentation

为解决秸秆焚烧难题,实现秸秆资源的高值化利用,采用玉米秸秆为主要发酵原料,添加泥炭进行中温厌氧发酵产沼气实验,研究了原料混合配比、接种量、起始pH对沼气发酵的影响,分析了玉米秸秆高值化利用的沼气发酵途径。研究结果表明:原料混合配比、接种量、起始pH对沼气发酵均有显著影响,玉米秸秆与泥炭的配比为7∶3、接种量50%、起始pH7.5、在35℃下的发酵产沼气,沼气日产气量达到最大值227.5 m L,总产气量最高为3 193.3 m L。秸秆与泥炭混合,其中所含大量纤维素及半纤维素适合微生物的生长,能为沼气发酵提供丰富的碳素营养;沼气发酵前后原料中纤维素和半纤维素的降解程度比较大,发酵前后纤维素由28.60%降到9.32%,半纤维素由27.67%降到1.51%。

In order to solve the problem of straw burning and realize the high value utilization of straw resource, corn straw was used in this paper as the main fermentation raw material and peat was added to carry out biogas fermentation. The effects of mixing ratio, inoculation amount and initial pH value on biogas fermentation were investigated and the biogas fermentation method of high value utilization of corn stalk was explored. The results showed that mixing ratio, inoculation amount and initial pH value had remarkable influences on biogas fermentation, and the maximum daily biogas production amount was 227.5 m L and the total biogas production amount was 3 193.3 m L with corn stalk and peat ratio of 7︰3, the inoculation amount of 50%, the initial pH value of 7.5, and fermentation temperature at 35 ℃. Cellulose and hemicelluloses in the mixture of stalk and peat could be conducive to the growth of biogas fermentation microorganisms and could provide abundant carbon nutrition for biogas fermentation. The degradation degree of cellulose and hemicelluloses in the raw material before and after the biogas fermentation was significant. The cellulose decreased from 28.60% to 9.32%; and hemicelluloses decreased from 27.67% to 1.51%.