猪粪与稻草混合沼气发酵投加方案优化设计

Optimization design of swine feces and straw feeding scheme on anaerobic co-digestion

以一实际工程为例,以产气稳定,满足用气要求,投料简易为目的,以沼气发酵工艺条件为约束,融合数学模拟与数理统计建立优化设计模型,优选粪草混合投加方案。结果表明:采用猪粪连续进料和稻草批量进料方式,控制温度35℃、碳氮比25、料液浓度9%、原料利用率53%左右工艺条件下,水力停留时间与稻草投加间隔时间的选择主要由猪粪和稻草的产气性能决定。水力停留时间为27 d左右,稻草投加间隔时间为20 d和37 d时,分别为最优解和满意解,产气量变差系数分别为0.000 6和0.004 5,猪粪日投加量与稻草每批投加量比分别为2.1和1.2,池容产气率分别为1.03 m3/(m3·d)和1.00 m3/(m3·d)。

For the purpose of the gas yield stable, meeting user requirements and operation simple, the optimization design model was established in this paper, making the biogas fermentation conditions as the restraint. Taking a practical project as an example, the satisfied swine feces and straw material feeding scheme was got in this experiment, combining mathematical modeling and statisti- cal analysis. The results showed that, in the biogas fermentation process conditions with swine feces continuous feeding and straw batch feeding mode, temperature at 35 ℃, C/N at 25, liquid con- centration at 9%, the utilization rate of raw materials at about 53%, hydraulic retention time and straw feeding interval depend mainly on swine feces and straw biogas production performances. The optimal solution was that, the hydraulic retention time equals 27 day approximately, straw feeding interval equals 20 day approximately, coefficient of variation of daily biogas production rate was 0.000 6, the ratio of swine feces daily dosage to straw each batch dosage was 2.1, tank volume aero genesis rate was 1.03 m^3/（m^3·d）, the ratio of swine feces daily biogas production to straw＇s was 10. The satisfactory solution was that, the hydraulic retention time was 27 day approximately, straw feeding interval was 37 day approximately, coefficient of variation of daily biogas production rate was 0.004 5, the ratio of swine feces daily dosage to straw each batch dosage was 1.2, tank volume aero genesis rate was 1.00 m^3/（m^3·d）.