根据加氢方式的不同，沼气提纯方式可分为原位加氢提纯和异位加氢提纯。所谓原位加氢提纯方式，是将外源氢气直接通入真是的沼气发酵体系中，在原位把沼气中的CO2转化成CH4，达到纯化升级沼气的目的，国外学者针对加氢提纯技术做了一系列探索性研究：
According to different hydrogenation methods, biogas purification methods can be divided into in-situ hydrogenation purification and ectopic hydrogenation purification. The so-called in-situ hydrogenation purification method refers to the direct introduction of exogenous hydrogen gas into a real biogas fermentation system, which converts CO2 from biogas into CH4 in situ, achieving the purpose of purifying and upgrading biogas. Foreign scholars have conducted a series of exploratory studies on hydrogenation purification technology:
1、 原位加氢提纯
1. In situ hydrogenation purification
以畜禽粪便和絮状污泥等固体废物的发酵体系为研究对象，实验证明通入外源氢气确实可以有效地提高沼气的生成速率和甲烷浓度，而沼气中的二氧化碳含量由对比实验中的38%降至12%，初步取得了沼气提纯效果。
Taking the fermentation system of solid waste such as livestock and poultry manure and flocculent sludge as the research object, experiments have shown that introducing exogenous hydrogen gas can effectively improve the generation rate and methane concentration of biogas, while the carbon dioxide content in biogas is reduced from 38% in the comparative experiment to 12%, achieving preliminary biogas purification effect.
此外为了解决原位沼气提纯中pH值升高的问题，他们开展了与酸性废物共发酵实验研究，把发酵体系的pH值有效地控制在8.0以下；针对气液传质速率低这一难点，采用中空纤维膜（HFM）组件曝气来代替传统微孔曝气方式，提高了H2在发酵液界面处的气液传质。
In addition, in order to solve the problem of pH increase in in-situ biogas purification, they conducted experimental research on co fermentation with acidic waste, effectively controlling the pH value of the fermentation system below 8.0; In response to the difficulty of low gas-liquid mass transfer rate, hollow fiber membrane (HFM) module aeration was used instead of traditional microporous aeration to improve the gas-liquid mass transfer of H2 at the fermentation liquid interface.
结果表明，在55℃发酵温度和150r/min搅拌强度下，当以1440mL/（L?d）的速率持续通气时，H2会被消耗完全，CH4的浓度达到90.2%，而在不通氢的发酵体系中，产生的沼气只含有55.4%的CH4，CO2的比重占44.6%。
The results showed that under a fermentation temperature of 55 ℃ and a stirring intensity of 150r/min, when continuously aerated at a rate of 1440mL/(L? D), H2 was completely consumed, and the concentration of CH4 reached 90.2%. However, in a hydrogen free fermentation system, the generated biogas only contained 55.4% CH4, with a proportion of CO2 accounting for 44.6%.
2、 异位加氢提纯
2. Ectopic hydrogenation purification
异位沼气提纯实验中，富集有嗜氢甲烷菌的厌氧反应器被作为单独的沼气提纯单元，经提纯处理后，沼气中CH4达到95%左右，成功实现沼气提纯。
In the experiment of heterotopic biogas purification, an anaerobic reactor enriched with hydrogen loving methane bacteria was used as a separate biogas purification unit. After purification treatment, the CH4 in biogas reached about 95%, successfully achieving biogas purification.
在氢气来源方面，除了利用可再生电能电解水制氢外，还可用焦炉气代替纯氢气，同步实现沼气提纯和焦炉气资源化双重目的。
In terms of hydrogen sources, in addition to utilizing renewable electricity to electrolyze water for hydrogen production, coke oven gas can also be used to replace pure hydrogen, achieving the dual goals of biogas purification and coke oven gas resource utilization simultaneously.
三、 国内加氢提纯技术发展现状
3、 Development status of domestic hydrogenation purification technology
近期，中国科学院成都生物研究所开展了高温原位加氢甲烷化制备生物天然气的研究，直接将氢气通入猪粪厌氧消化反应器内，平均甲烷产率从未加氢阶段的222L/kgVS提高至292L/kgVS，平均相对甲烷含量从66%提高至83%。
Recently, the Chinese Academy of Sciences Chengdu Institute of Biology has carried out the research on the preparation of biological natural gas by high-temperature in-situ hydro methanation. Hydrogen is directly introduced into the pig manure anaerobic digestion reactor, and the average methane yield has increased from 222L/kgVS in the hydrogenation stage to 292L/kgVS, and the average relative methane content has increased from 66% to 83%.
通过微生物多样性分析表明，严格氢营养型产甲烷菌Methanoculleus、Methanobrevibacter、Methanobacterium是高温原位加氢甲烷化系统的主要产甲烷菌，且外源氢气的加入会弱化同型产乙酸菌与氢营养型产甲烷菌之间的互营协作关系，而作为种间电子传递载体的甲酸钠的加入有助丙酸降解产乙酸，从而保证系统的稳定。
Through microbial diversity analysis, it was found that strictly hydrogenotrophic methanogens, such as Metanoculleus, Metanobrevibate, and Metanobacterium, are the main methanogens in the high-temperature in-situ hydrogenation methanation system. The addition of exogenous hydrogen gas weakens the synergistic relationship between homotrophic acetic acid producing bacteria and hydrogenotrophic methanogens, while the addition of sodium formate as an interspecific electron transfer carrier helps to degrade propionic acid and produce acetic acid, To ensure the stability of the system.
企业二维码
2023-08-21
鲁公网安备37011202000764号号