Dark fermentation-light fermentation coupled biological hydrogen preparing process

Abstract

The invention discloses a dark fermentation-light fermentation coupled biological hydrogen preparing process. According to the dark fermentation-light fermentation coupled biological hydrogen preparing process, a bipolar membrane electrodialysis unit is added behind a dark fermentation reactor, the components of the outgoing water obtained after dark fermentation are separated, thus the concentrated acetic acid is obtained, after pH regulation, the concentrated acetic acid is taken as incoming water of a light fermentation reactor, and meanwhile, the not utilized substrate is recycled and returns to the dark fermentation reactor to be reutilized. The product inhibition at the dark fermentation hydrogen production stage can be relieved, the pH of a fermentation system is controlled to be within the optimal range, the substrate is effectively recycled and reutilized, the total utilization ratio of the substrate is improved, the optimal substrate, namely, acetic acid is provided for the light fermentation hydrogen production stage, NH<4+> in the outgoing water obtained by dark fermentation is removed, then the inhibiting for the dinitrogenase of light fermentation bacteria is relieved, meanwhile, the interception and separation for the dark fermentation bacteria are completed, and the steps including centrifugalization, filtering and sterilization of the original process are replaced; the optimal hydrogen production conditions are provided for the dark fermentation and light fermentation stages, and the two-step coupled hydrogen production efficiency adopting the dark fermentation bacteria and the light fermentation bacteria is improved.

Description

technical field [0001] The invention relates to the technical field of hydrogen production by fermentation, in particular to a dark-light fermentation coupled biological hydrogen production process. Background technique [0002] Dark fermentation bacteria can decompose macromolecular organic matter into small molecular organic acids and alcohols to obtain the energy and reducing power needed to maintain their own growth, and release part of hydrogen quickly by releasing electron accumulation. Among the small molecular organic acids produced, only formic acid can be further decomposed to release H2 and CO2, and other organic acids cannot be further decomposed by dark fermentation bacteria and accumulate in large quantities, resulting in low hydrogen production efficiency of dark fermentation bacteria and becoming a major hydrogen producer for dark fermentation bacteria. Bottleneck problems faced by large-scale applications. However, light-fermenting bacteria can utilize smal...

AI Technical Summary

Problems solved by technology

However, in the continuous production process, the fermentation products in the dark fermentation stage are significantly inhibited, resulting in low substrate utilization, and the dark fermentation effluent needs complex treatments such as centrifugation and filtration, adding chemicals, and secondary sterilization to adjust to photosynthetic bacteria. Optimum conditions, increased footprint and processing steps, greatly limit the scale-up production of coupled biohydrogen

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