不同压缩比和青贮时间下玉米秸秆厌氧发酵性能研究

Anaerobic Digestion Performance of Corn Stalk under Different Compression Ratio and Silage Time

青贮是保障秸秆长期贮存和可持续供应的重要方式,秸秆压缩后青贮更便于贮存和运输。选用玉米秸秆为原料,采用不同时间、不同压缩比进行青贮,分析了相应的玉米秸秆成分变化,并对压缩青贮后秸秆进行了厌氧发酵产气特性实验。结果表明:玉米秸秆在长期青贮时,采取高密度贮存可有效减少干物质损失,青贮300 d时,未压缩组的总固体(TS)回收率为26.5%,1∶6压缩组的TS回收率为51.0%,较未压缩组提高了92.5%。延长青贮时间会显著降低玉米秸秆沼气产量,青贮40 d时,未压缩组的累计产气量为23.2 mL/g,而1∶6压缩组为282.9 mL/g;青贮300 d时,未压缩组产气潜力丧失,1∶6压缩组累计产气量达200.3 mL/g,说明采用高压缩比对保持青贮秸秆的产沼气性能更为有利。

Silage is an important way to ensure long-term storage and sustainable supply of straw,and more convenient for storage and transportation after compression.However,when silage compressed straw was used for anaerobic digestion to produce biogas,there is a lack of influence on the biogas yield performance of compressed silage parameters.Corn stovers were used as substrate to study the changes of characteristics after different time and different ratios of compressed silage,and the anaerobic digestion biogas yield characteristics were tested.The results showed that with the extension of silage time,the material loss of corn stover was serious,the high-density of corn stover in the long-term silage can effectively reduce the dry matter loss.After 300 d of silage,the cellulose mass fraction of corn stalks was decreased significantly.But after compression,the mass fraction of cellulose and hemicellulose was higher than that of the original straw by 8.5%and 10.6%under the 1∶6 compression ratio,respectively.The TS recovery rate of the uncompressed group was 26.5%at 300 d silage,and the TS recovery rate of the 1∶6 compression group was 51.0%.It was 92.5%higher than that of the uncompressed group.The prolongation of silage time significantly reduced the biogas potential of corn stover.At 40 d of silage,the cumulative biogas yield of the uncompressed group was 23.2 mL/g,the 1∶6 compression group was 282.9 mL/g.At 300 d of silage,the biogas yield potential of the uncompressed group was lost(2.3 mL/g),and the cumulative biogas yield of the 1∶6 compression group was 200.3 mL/g,indicating that high compression ratio was more beneficial to maintain the biogas performance of silage straw.