根據(jù)加氫方式的不同，沼氣提純方式可分為原位加氫提純和異位加氫提純。所謂原位加氫提純方式，是將外源氫氣直接通入真是的沼氣發(fā)酵體系中，在原位把沼氣中的CO2轉(zhuǎn)化成CH4，達(dá)到純化升級(jí)沼氣的目的，國(guó)外學(xué)者針對(duì)加氫提純技術(shù)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、 原位加氫提純
1. In situ hydrogenation purification
以畜禽糞便和絮狀污泥等固體廢物的發(fā)酵體系為研究對(duì)象，實(shí)驗(yàn)證明通入外源氫氣確實(shí)可以有效地提高沼氣的生成速率和甲烷濃度，而沼氣中的二氧化碳含量由對(duì)比實(shí)驗(yàn)中的38%降12%，初步取得了沼氣提純效果。
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.
此外為了解決原位沼氣提純中pH值升高的問(wèn)題，他們開展了與酸性廢物共發(fā)酵實(shí)驗(yàn)研究，把發(fā)酵體系的pH值有效地控制在8.0以下；針對(duì)氣液傳質(zhì)速率低這一難點(diǎn)，采用中空纖維膜（HFM）組件曝氣來(lái)代替?zhèn)鹘y(tǒng)微孔曝氣方式，提高了H2在發(fā)酵液界面處的氣液傳質(zhì)。
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.
結(jié)果表明，在55℃發(fā)酵溫度和150r/min攪拌強(qiáng)度下，當(dāng)以1440mL/（L?d）的速率持續(xù)通氣時(shí)，H2會(huì)被消耗完全，CH4的濃度達(dá)到90.2%，而在不通氫的發(fā)酵體系中，產(chǎn)生的沼氣只含有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、 異位加氫提純
2. Ectopic hydrogenation purification
異位沼氣提純實(shí)驗(yàn)中，富集有嗜氫甲烷菌的厭氧反應(yīng)器被作為單獨(dú)的沼氣提純單元，經(jīng)提純處理后，沼氣中CH4達(dá)到95%左右，成功實(shí)現(xiàn)沼氣提純。
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.
在氫氣來(lái)源方面，除了利用可再生電能電解水制氫外，還可用焦?fàn)t氣代替純氫氣，同步實(shí)現(xiàn)沼氣提純和焦?fàn)t氣資源化雙重目的。
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、 國(guó)內(nèi)加氫提純技術(shù)發(fā)展現(xiàn)狀
3、 Development status of domestic hydrogenation purification technology
近期，中國(guó)科學(xué)院成都生物研究所開展了高溫原位加氫甲烷化制備生物天然氣的研究，直接將氫氣通入豬糞厭氧消化反應(yīng)器內(nèi)，平均甲烷產(chǎn)率從未加氫階段的222L/kgVS提高292L/kgVS，平均相對(duì)甲烷含量從66%提高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%.
通過(guò)微生物多樣性分析表明，嚴(yán)格氫營(yíng)養(yǎng)型產(chǎn)甲烷菌Methanoculleus、Methanobrevibacter、Methanobacterium是高溫原位加氫甲烷化系統(tǒng)的主要產(chǎn)甲烷菌，且外源氫氣的加入會(huì)弱化同型產(chǎn)乙酸菌與氫營(yíng)養(yǎng)型產(chǎn)甲烷菌之間的互營(yíng)協(xié)作關(guān)系，而作為種間電子傳遞載體的甲酸鈉的加入有助丙酸降解產(chǎn)乙酸，從而保證系統(tǒng)的穩(wěn)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.
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2023-08-21
