牛粪与秸秆干式厌氧共发酵性能与流变特性研究

Performance and rheological characteristics in dry anaerobic co-digestion of cow manure and corn straw

为了研究牛粪(CM)与玉米秸秆(CS)连续干式共发酵的性能与物料流变特性,在卧式不锈钢横推流式反应器中,将CM与CS分别按照2∶1,1∶1,1∶2的总固体(TS)质量比混合,在进料TS含量分别为20%,25%和30%的条件下进行厌氧共发酵试验。试验结果表明:CM与CS干式共发酵的最佳进料TS含量为25%,最佳CM和CS配比为1∶2,容积CH4产量最高为1.63 L/(L·d),发酵后期稳定在1.46~1.61 L/(L·d);随着进料TS含量的增加,进料表现出更高的剪切应力,在进料TS含量为25%的条件下,发酵物料的黏度达到30 Pa·s左右,但未观察到明显的抑制作用;当进料TS含量升高至30%时,发酵物料的黏度达到35 Pa·s左右,共发酵效率下降,物料的高黏度可能是导致CM与CS混合共发酵效率下降的原因;发酵物料的黏度随着CM占比的增加而增大,CM对物料流动的不利程度高于CS。

In this study,the performance and rheological characteristics in dry anaerobic co-digestion of cow manure(CM)and corn straw(CS)were investigated.CM and CS were mixed in a horizontal stainless steel push-flow reactor with the mixing ratio of 2∶1,1∶1 and 1∶2,respectively.The total solid(TS)content of anaerobic co-digestion experiment was 20%,25%and 30%,respectively.The results showed that the optimal TS content for dry co-digestion of CM and CS mixture was 25%,and the optimal feedstock ratio was 1∶2.The highest volumetric production of CH4was 1.63 L/(L·d).After that,the volumetric production stabilized at 1.46~1.61 L/(L·d).With the increase of TS content,the feed substrates shear stress was higher.When the TS content was 25%,the viscosity of substrates reached 30 Pa·s.But obvious inhibition was not observed.When the TS content increased to 30%,the viscosity of substrates reached 35 Pa·s,and the co-digestion efficiency decreased.The increase of CM ratio will cause the viscosity of the material increased.CM had a stronger adverse effect on material flow than CS.