Abstract

This study evaluated the effect of hydraulic retention time (HRT) on the simultaneous hydrogen and ethanol production in two anaerobic fluidized bed reactors (55 °C) from mono-fermentation of cellulosic hydrolysate (AFBR-C) and the fermentation of glucose and xylose as co-substrates (AFBR-GX). In AFBR-C, the HRT was decreased from 24 to 8 h, while in AFBR-GX, the HRT was decreased from 16 to 0.5 h. The carbohydrate concentration was maintained at 4 g/L (AFBR-GX) and 2 g/L (AFBR-C). In AFBR-C, the main results observed by decreasing the HRT from 24 to 8 h were the increase in H₂ yield (0.6–1.1 mol H₂/mol hexose) and ethanol concentration (0.02–0.48 g/L). However, the H₂ yield in AFBR-GX decreased from 0.4 to 0.1 mol H₂/mol hexose by decreasing the HRT from 16 to 0.5 h. Additionally, the shortest HRTs applied to the AFBR-C (8 h) and AFBR-GX (0.5 h) resulted in the maximum hydrogen production rates of 115.7 and 279.9 mL H₂/h L, the maximum energy yields of 7.4 and 47.7 kJ/h L, and EtOH molar fractions of 58.9 and 50.2%, respectively.

Graphic abstract

摘要

这项研究评估了水力停留时间（HRT）对两个厌氧流化床反应器（55°C）中纤维素水解产物（AFBR-C）的单发酵以及葡萄糖和木糖发酵的同时产生氢和乙醇的影响共底物（AFBR-GX）。在AFBR-C中，HRT从24小时降低至8小时，而在AFBR-GX中，HRT从16小时降低至0.5小时。碳水化合物浓度维持在4 g / L（AFBR-GX）和2 g / L（AFBR-C）。在AFBR-C中，通过将HRT从24小时降低到8小时观察到的主要结果是H ₂产量（0.6–1.1 mol H ₂ / mol己糖）和乙醇浓度（0.02–0.48 g / L）的增加。然而，AFBR-GX中的H ₂产率从0.4 mol H ₂降低至0.1 mol H ₂/ mol己糖，将HRT从16 h降低至0.5 h。此外，应用于AFBR-C（8小时）和AFBR-GX（0.5小时）的最短HRT导致最大氢气产生速率为115.7和279.9 mL H ₂ / h L，最大能量产生为7.4和47.7 kJ / h L和EtOH摩尔分数分别为58.9％和50.2％。

图形摘要