Abstract: Biogas fermentation has two general problems, low production rate and low methane concentration. From the reaction mechanism for methane formation, if external H₂ is supplied, CO₂ in the biogas can be converted into CH₄, leading to increased yield and concentration of methane. Recently published experimental studies reported that biogas could be purified and upgraded to a quality as biomethane with the addition of hydrogen gas. However, to make this technology practical, two key problems should be resolved. One is to intensify H₂ transfer from gas phase to aqueous phase at low mixing speeds. The other is to obtain hydrogen gas with economical methods. A scheme is suggested for biogas upgrading through the integration of H₂ generation by photoelectrocatalysis and CH₄ production by anaerobic fermentation.

Key words: biogas upgrading/purification, biomethane, hydrogen gas, anaerobic fermentation, in situ methane enrichment

摘要： 沼气发酵过程存在产气速率低和甲烷浓度低两个普遍问题。从甲烷生成的反应机理来看，如果提供充足的氢气，能够把沼气中的CO₂成分转化为CH₄，既提高了甲烷的产量，又提高了甲烷的浓度。介绍了最近国内外在这个方向上的探索性研究成果。实验表明，利用外源氢气确实可以纯化升级沼气，在一定条件下还可以达到生物甲烷的品质（即CH₄浓度高于95%）。分析了这项技术实用化需要解决的两个关键问题：强化H₂气液传质及获取廉价氢源。最后，对这个方向进行了展望，并提出了一个光电催化产氢与厌氧发酵产甲烷耦合的设想方案。

关键词: 沼气提纯, 生物甲烷, 氢气, 厌氧发酵, 原位沼气纯化