对比分析进水基质浓度对乙醇型和丁酸型发酵制氢系统的影响

摘要

In the present study, the anaerobic contact reactor (ACR) was used to produce hydrogen from diluted molasses by anaerobic fermentation, and an ethanol-type fermentation and butyric-type fermentation were established by keeping the effluent pH of the two reactors at 4.5—5.0 and 5.5—6.0, respectively. And then the comparison of the impact of influent substrate concentration on the performance of the above two reactors was investigated. For the ethanol-type fermentation system, the fermentative hydrogen-producing efficiency was enhanced when the influent chemical oxygen demanding (COD) was increased from 5000 to 12000 mg·L-1 under the HRT of 6 h, whereas, the feedback inhibition was turn to be functioned as the influent COD was increased to 15000 mg·L-1. It was found that the hydrogen production rate (HPR), specific hydrogen rate of sludge (SHPR) and hydrogen yield (HY) was peaked at 68.8 L·d-1, 744.5 ml H2·(g VSS·d)-1 and 2.3 mol H2·(mol glucose)-1,respectively, when the influent COD was 12000 mg·L-1. For the butyric-type fermentation system, the hydrogen producing efficiency was decreased on the whole as the influent COD was increased from 5000 to 20000 mg·L-1 under the HRT of 8 h. It also showed that the maximum value of SHPR and HY was 159.6 ml H2·(g VSS·d)-1 and 1.0 mol H2·(mol glucose)-1, respectively, when the influent COD was 5000 mg·L-1. It indicated that the hydrogen-producting capability of ethanol-type fermentation was better than that of butyric-type fermentation.%以糖蜜废水为基质,将两套厌氧接触式发酵制氢反应器(ACR)出水pH分别控制在4.5~5.0、5.5~6.0的水平,通过逐级提升进水 COD 浓度方式,系统对比分析基质浓度对乙醇型和丁酸型发酵制氢系统的影响.结果显示,对于乙醇型发酵制氢系统而言,当HRT=6 h,进水COD从5000逐步提升至12000 mg·L-1时,反应器的产氢效能逐步得到增强,但当COD进一步提升至15000 mg·L-1时,底物反馈抑制作用开始显现,因而在进水COD为12000 mg·L-1时,ACR产氢性能最佳,系统的产氢速率、污泥比产氢速率和单位基质氢气转化率分别为68.8 L·d-1、744.5 ml H2·(g VSS·d)-1、2.3 mol H2·(mol葡萄糖)-1.对于丁酸型发酵制氢系统而言,当HRT=8 h,在进水COD从5000提升至20000 mg·L-1过程中,ACR产氢效能总体呈下降趋势,在进水COD为5000 mg·L-1时,系统的污泥比产氢速率和单位基质氢气转化率最大,分别为159.6 ml H2·(g VSS·d)-1、1.0 mol H2·(mol葡萄糖)-1.研究结果表明,在进水COD为500~20000 mg·L-1的运行中,ACR乙醇型发酵系统的产氢效能优于丁酸型发酵制氢系统.