预处理对打捆麦秸贮存和厌氧生物产沼气的影响

秸秆的长期贮存是秸秆沼气工程长期运行的重要保障,预处理是提高秸秆产气性能的常用方法.为此研究了打捆麦秸贮存与预处理一体化的可行性,分析了麦秸预处理后打捆贮存前后麦秸理化特性、物质结构以及厌氧发酵产气特性的变化.结果表明,将麦秸直接打捆后贮存120 d,对麦秸理化特性、物质结构及产气性能的影响均不明显,影响最大的是堆体上层的麦秸,产气量也仅下降了7.40%;将麦秸用NaOH处理后打捆贮存对提高麦秸干物质(total solid,TS)产气量有一定促进作用,麦秸TS产气量较未贮存麦秸和直接打捆贮存后的麦秸(CK)分别提高了7.02%～8.31%和5.68%～16.96%,对麦秸理化特性的影响不明显;麦秸经尿素处理后打捆贮存,不利于麦秸后续产沼气,麦秸TS产气量较CK下降了2.8%～7.71%;麦秸贮存过程中,将麦秸直接暴露于空气中对麦秸有机物的保存及后续产沼气利用均不利,但影响并不显著,CK和尿素处理堆体上层麦秸TS产气量分别下降了7.40%和4.25%.

Effect of Pretreatment on Storage and Biogas Production of Baling Wheat Straw

Long-term storage of crop straw is very important for biogas plant while pretreatment is always used to improve biogas production of crop straw. Feasibility of integrating the storage with pretreatment of baling wheat straw was studied. Changes of physico-chemical properties and the biogas productivity of wheat straw obtained before and after 120 days storage were analyzed. The results showed that it was feasible to directly bale wheat straw for storage (control) and storage treatment had little effect on the physico-chemical properties, structure and biogas productivity of wheat straw. After 120 day's storage, biogas production potential of the surface wheat straw of pile was decreased by 7.40%. Integrating NaOH pretreatment with straw storage was good for biogas production of wheat straw and the total solid (TS) biogas yield was increased by 7.02%-8.31% (compared to that of wheat straw without storage) and 5.68%-16.96% (compared to that of storage without alkaline pretreatment), respectively. Storage with urea treatment was adverse to biogas production of wheat straw and the contents of cellulose and hemicellulose of wheat straw were decreased by 18.25%-27.22% and 5.31%-16.15% and the TS biogas yield was decreased by 2.80%-7.71% after 120 day's storage. Exposing wheat straw to the air during the storage process was adverse to the conserving of organic matter and biogas utilization of wheat straw, but the influence was very slight and the TS biogas yield of wheat straw obtained from pile surface of control and urea treatment was decreased by 7.40% and 4.25%, respectively.