基于聚气释压实现厌氧干发酵自搅拌的模拟试验

目的]为解决干发酵传质限制和搅拌能耗高等问题提供新思路。方法]提出基于"周期聚气增压,瞬时释气泄压"实现自搅拌。采用空气为模拟气源,以盒子分形维数为搅拌效果定量评价指标,研究了聚气压力、释压时间、聚气空间分布对搅拌效果的影响。结果]分形维数随聚气压力的增加而增大,当压力逐步升至0.70 MPa时,反应器纵截面分形维数相对搅拌前增加了12.06%,搅拌效果明显增加;当释压时间为0.60~0.80 s,聚气压力为0.30~0.40 MPa时,分形维数变化率达最大值0.158 4,搅拌效果最佳。结论]聚气释压可实现干发酵自搅拌。

Simulation Test of Self-stirring in Dry Anaerobic Fermentation Based on Releasing Pressurized Biogas

Objective] In order to research new approaches for solving mass transfer limitation and high mixing energy consumption in dry anaerobic fermentation process.Method] A novel technology based on "accumulate pressurized biogas in cycles,release gas instantaneously to depressurizing" was designed as a mixing strategy which could achieve self-stirring.The experiment was carried out with compressed air as pressurized biogas and regarded box fractal dimension as quantitative evaluation index for mixing effect of materials.Effects of gas gathering pressure,pressure releasing time,gas distribution on self-stirring were studied.Result] The results showed that fractal dimension linearly tended to increase in pace with gas pressure and increased by 12.06％ as pressure gradually reached 0.70 MPa and self-mixing effect appeared obvious.The fractal dimension grew with shortening the time and incremental gas pressure and attained positive peak 0.158 4 in condition of 0.60-0.80 s and 0.30-0.40 MPa.The mixing effect was more conspicuous.Conclusion] Releasing pressurized biogas can achieve selfmixing in dry anaerobic fermentation.