沼气产量影响因子研究

Influence factors of biogas yields

【目的】综合研究秸秆类型、粪秆配比及温度对沼气产量的影响,为提高沼气产量提供理论依据。【方法】在室内模拟农村户用沼气发酵过程,运用信息熵原理,研究了秸秆类型(稻秆、麦秆、玉米秆)、鸡粪与秸秆配比(干物质质量比分别为1∶1,2∶1,3∶1)、发酵温度(20～40℃)、尿素、纤维素酶等因子对沼气产量的影响。【结果】在20～40℃,稻秆、麦秆、玉米秆与鸡粪配比时,沼气总产气量分别为407321.6,413096,478417.9mL,玉米秆-鸡粪组合沼气产量较麦秆-鸡粪组合和稻秆-鸡粪组合分别高17.6%和15.5%。鸡粪与秸秆配比显著影响沼气产量,表现为2∶1>1∶1>3∶1。在20～30℃,沼气产量随温度的升高逐渐增加,在30～35℃时达最大值,之后逐渐降低。沼气产量与温度呈一元二次回归关系,各处理最高沼气产量对应最佳温度为32～35℃。20℃发酵中期(28d),向发酵液料中分别添加尿素和纤维素酶均能明显增加沼气产量,分别平均提高93.7%和40.9%。信息熵原理k值表明,温度是影响沼气产量的首要因子,其次是鸡粪与秸秆配比,秸秆类型的影响最小。在20℃发酵中期,鸡粪与秸秆配比对沼气产量的影响高于外来添加物质尿素和纤维素酶。【结论】鸡粪与玉米秆按2∶1配比、发酵温度控制在32～35℃,可获得较高沼气产量。沼气产量是秸秆类型、鸡粪与秸秆配比、发酵温度及外源物(如尿素和纤维素酶)综合作用的结果,合理调控各因子可获得较高的沼气产量。

[Objective] The study was to explore the effect of straw types, manure-straw ratio and temperature on biogas yields. [Method] An indoor simulation experiment of rural households biogas digester was designed to study the influence factors of biogas yields based on information entropy theory. The factors included straw types （rice, wheat, corn straw）, manure-straw ratio, fermentation temperature （20 - 40 ℃）, urea,cellulose. [Result] The results showed that biogas yields of mixture of chicken manure and corn straw were 17.6% higher than that of chicken manure and wheat straw and 15.5% higher than that of chicken manure and rice straw in the same ratio. The manure-straw ratio had significant effect on biogas yields,showing 2 ： 1〉1 ： 1〉3 ： 1. With regression analysis,the optimum temperature to gain the maximum biogas yields was between 32 and 35 ℃. In the mid-fermentation （28 d） under 20 ℃, urea and cellulose was added respectively, which can significantly increase gas production （increasing rate 93. 7% and 40.9% separately）. Information entropy theory k-value showed that temperature was the primary impact factor of biogas yields, followed by chicken manure-straw ratio, straw types least affected. In the mid-fermentation （28 d） under 20 ℃ ,chicken manure-straw ratio had more effect on yield of biogas than urea and cellulose. [Conclusion] Chicken manure-corn straw ratio 2 ： 1 under 32--35 ℃ can obtain higher gas production. Biogas yield results from the joint effects of straw type, chicken manure-straw ratio, fermentation temperature and additive （such as urea and cellulose）, therefore biogas yields could be improved by rational regulation of above related factors.