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乙醇-沼气双发酵耦联工艺的应用有望实现乙醇工业工艺废水“零排放”的目标.本研究对该耦联工艺的回用配料水——中温沼液中的悬浮物对乙醇发酵的影响进行了考察,并对其去除方法进行了确定.结果表明,沼液中悬浮物的存在会促进酵母细胞的繁殖,提高发酵速率,但副产物甘油及小分子有机酸的量大幅上升,而主产物乙醇的生成量减少,悬浮物对乙醇合成的临界抑制浓度为0.35 g·L-1(干重).采用不同的絮凝剂及絮凝方式对沼液中的悬浮物进行去除,发现絮凝剂聚合氯化铝(PAC,300 mg·L-1)与阳离子聚丙烯酰胺(CPAM,2 mg·L-1)协同处理时效果最佳,对沼液浊度、色度的去除率分别为92.4%、23.7%,所得上清液的悬浮物粒径小于2μm,PAC、CPAM的残留量分别为0.82、0.03mg·L-1.絮凝处理后消除了悬浮物对乙醇合成的抑制作用,且絮凝处理后沼液回用的发酵性能略优于离心所得沼液回用的发酵水平,达到了预期的目的.
The application of ethanol-biogas double-coupling process is expected to achieve the goal of “zero discharge” of ethanol industrial wastewater.In this study, the reuse of the coupling process of water-medium temperature biogas slurry suspended in ethanol fermentation The results showed that the presence of suspended matter in biogas slurry would promote the propagation of yeast cells and increase the fermentation rate, but the amount of by-product glycerol and small molecule organic acids increased sharply, while The main product of ethanol production decreased, the critical concentration of suspended solids on ethanol synthesis was 0.35 g · L-1 (dry weight) .Different flocculants and flocculation of the slurry in the removal of suspended solids, found flocculant When PAC (300 mg · L-1) and CPAM (2 mg · L-1) were synergistic, the best turbidity and color removal rates were 92.4 % And 23.7% respectively, the particle size of the supernatant was less than 2μm, the residues of PAC and CPAM were 0.82,0.03mg · L-1, respectively. The flocculation treatment abolished the inhibitory effect of suspended solids on ethanol synthesis, After treatment, the fermentation performance of biogas slurry was slightly better than that of biogas slurry The level of fermentation, to achieve the desired purpose.