不同预处理条件对棉秆厌氧发酵产沼气的影响

Effects of different pretreatment conditions on biogas production by anaerobic fermentation of cotton stalk

为探索合理的预处理方法以实现棉秆的高效厌氧发酵,研究了高温处理、NaOH处理与生物处理3种预处理方式对棉秆厌氧发酵产沼气的影响。经预处理的棉秆以8%的总固体质量分数,在常温((23±2)℃)下进行沼气发酵试验。结果表明,经NaOH及生物预处理,棉秆的木质纤维结构破坏较明显,而高温预处理对棉秆的表观结构影响不大。3种预处理均能有效缩短发酵启动时间,并不同程度提高棉秆产沼气的能力,作用大小依次为:NaOH处理>高温预处理>生物预处理。其中以质量分数为4%的NaOH对棉秆(含水率为60%)处理10 d的效果最佳,发酵61 d后的总产气量可达31 022.5 mL,日均产气量为508.57 mL/d,总固体产气率、挥发性固体产气率分别为193.89、216.30 mL/g,要远高于其他处理及对照,有效地提高了棉秆厌氧发酵的效率。

In order to search for fitting pretreatment methods in effective anaerobic fermentation of cotton stalks,effects of three pretreatments including high temperature,alkali treatment and microbial inoculation on biogas production by anaerobic fermentation of cotton stalks were studied.The pretreated cotton stalks were fermented in the biogas production experiments with total solid weight percentage of 8% under room temperature of（23±2）℃.The results showed that in cotton stalks pretreated with NaOH and microbial inoculation,the structure of lignocellulose was broken clearly,while high temperature affected the external structure indistinctively.All the three pretreatments effectively shortened the starting period of anaerobic fermentation,and improved the ability to biogas production of cotton stalks.Effects of the three pretreatments on biogas production followed the order that： alkali treatment high temperature microbial inoculation.Of all the conditions,the pretreatment of 4%（w/w） NaOH with 10 days treating period for cotton stalks（with 60% moisture） exhibited the best effect,which could gain the total gas production of 31 022.5 mL after 61 day fermentation.And in this fermentation,the daily average gas production achieved 508.57 mL/d,TS gas production and VS gas production reached 193.89 mL/g and 216.30 mL/g separately,which were much higher than those of the control and other pretreatments.This indicated that this kind of alkali treatment was the optimal,efficiently promoted biogas production in anaerobic fermentation of cotton stalks.