牛粪与玉米秸秆不同配比厌氧发酵的产气性能

Biogas production performance of anaerobic fermentation with different proportions of cattle manure and corn straw

【目的】研究牛粪与玉米秸秆不同配比混合厌氧发酵的产气性能,为提高厌氧发酵产气效率提供依据。【方法】采用自制的1 L厌氧反应器,以牛粪和玉米秸秆为发酵原料,设置牛粪与玉米秸秆干物质质量比分别为10∶0(对照),8∶2,6∶4,4∶6,2∶8和0∶10共6个处理,在物料总干物质质量分数8%、发酵温度(35±1)℃条件下进行厌氧发酵产气试验,分析不同产气指标的变化规律。【结果】在产气方面,牛粪与玉米秸秆按不同比例混合厌氧发酵的4个处理日产气量变化趋势为先快速升高后平稳下降,发酵第2~3天达到产气峰值,较对照提前2~3 d;当牛粪与玉米秸秆的干物质质量比为2∶8时,累积产气量、甲烷总产量及挥发性固体产甲烷量均高于其他处理,分别达13061.7 mL、6911.4 mL和0.170 L/g,较单一牛粪发酵处理(对照)分别提高52.47%,41.48%和34.92%。在发酵系统稳定性方面,牛粪与玉米秸秆不同比例混合厌氧发酵的4个处理均在发酵第5天pH值达到最低,挥发性脂肪酸质量浓度达到最高,较对照提前2 d达到极值;发酵5 d时,牛粪与玉米秸秆干物质质量比为2∶8的处理pH值低于其他处理,为5.75,较对照降低了7.70%;挥发性脂肪酸质量浓度高于其他处理,为1675.6 mg/L,较对照提高了59.04%。【结论】牛粪与玉米秸秆混合厌氧发酵产气效果优于单一原料发酵,且二者干物质质量比为2∶8时厌氧发酵具有较好的产气特性和发酵潜力。

【Objective】The biogas production characteristics of anaerobic fermentation of cattle manure and corn straw with different proportions were studied to provide basis for improving efficiency.【Method】Experiments were conducted in self-made 1 L anaerobic reactor with cattle manure and corn straw(dry matter)ratios of 10∶0(the control treatment),8∶2,6∶4,4∶6,2∶8 and 0∶10 under the condition of 8%dry matter quality fraction and(35±1)℃.Biogas characteristics during anaerobic digestion were tested.【Result】The daily biogas production increased rapidly and then decreased steadily in four co-digestion treatments with cattle manure and corn straw,and the peak of biogas production was reached on the 2nd or 3rd day,which was 2 to 3 days earlier than the control treatment.When cattle manure and corn straw ratio was 2∶8,the cumulative biogas production,total methane production and volatile solid methane production were higher than other treatments,reaching 13061.7 mL,6911.4 mL and 0.170 L/g,which were 52.47%,41.48%and 34.92%higher than that of the control treatment.For fermentation system stability,the pH value and mass concentration of volatile fatty acid reached the valley and peak on the 5th day in four treatments with cattle manure and corn straw co-digestion,respectively,which was 2 days ahead the control treatment.The lowest pH value of 5.75 and highest volatile fatty acids mass concentration of 1675.6 mg/L were abstained in the group of 2∶8,which were 7.70%lower and 59.04%higher than the control treatment,respectively.【Conclusion】The effects of co-digestion of cattle manure and corn straw were better than that of single material.Higher biogas production efficiency and potential were abstained when cattle manure and corn straw dry matter ratio was 2∶8.