基于连续运行条件下的稻秸干法厌氧发酵中试研究

Effect of operating conditions on the dry anaerobic fermentation of rice straw

为了探索连续进料运行下秸秆干法厌氧发酵的产气情况,设计了一种适用于稻秸干法厌氧发酵中试系统,研究了牛粪单发酵启动试验、不同进料方式和氮源添加下的产气特征并且进行了技术经济性分析评估。结果表明:中试装置可实现含固率为20%的秸秆物料均匀混合,提高进料效率和实现连续发酵均衡产气。发酵启动试验阶段,牛粪单发酵29 d后具备处理稻秸所需的最佳厌氧微生物体系、适宜的发酵温度等,从而使连续进料阶段快速启动。在连续进料稳定运行阶段,秸秆进料量80 kg·d^-1并添加猪粪(干质量)4.54 kg·d^-1为补充氮源,单日CH4产气量从137.28 L·kg^-1VS达到227.8 L·kg^-1VS,并能连续维持20~22 m3·d^-1。对于缺乏猪粪等氮源的地区可采用一次性投加的方式,单次补充68.1 kg猪粪(干质量)且定期补充时间为20 d。研究表明,该适用于稻秸干法厌氧发酵中试系统技术可行且可实现连续进出料和稳定运行产气,并产生可观的经济效益。

To investigate biogas production during continuous-feed dry anaerobic rice straw fermentation, the aims of the present study are to investigate the effects of single fermentation of cow manure, feeding method and nitrogen source on biogas production and on technical economic analysis and evaluation. The pilot system could reach uniform mixing of straw materials at a solid content of 20%, thereby achieving continuous fermentation and balanced biogas production. At the beginning of the experiment, the optimal anaerobic microbial system and suitable fermentation temperature for rice straw treatment were available after 29 d of the single fermentation of cow manure. Thus, the continuous feeding phase test could be started quickly. At the continuous-feeding and stable-operation stage, during which 80 kg·d^-1 feeding quantity and 4.54 kg·d^-1(TS)pig manure were used as supplementary nitrogen sources, the daily biogas CH4 production increased significantly from 137.28 L·kg^-1 VS to 227.8 L·kg^-1 VS, and total production could be maintained at 20~22 m^3·d^-1. For area where pig manure source is scarce, the one-time addition of 68.1 kg(TS)pig manure could be adopted. The regular replenishment period was every 20 d.These results indicate that dry anaerobic rice straw fermentation is feasible and can facilitate continuous-feed and stable-operation biogas production, which will have great application prospects and economic benefits.