1、氧氣和氮氣
1. Oxygen and nitrogen
沼氣在厭氧條件下產(chǎn)生,氧氣和氮氣一般不存在于沼氣中,但是如果空氣從外部進(jìn)入到系統(tǒng)中,就可能發(fā)現(xiàn)氧氣和氮氣的存在。如果沼氣中存在氧氣,會慢慢被消耗掉。氮氣存在則表明沼氣發(fā)酵過程存在反硝化作用,或者反應(yīng)器出現(xiàn)滲漏。在填埋場沼氣中越容易發(fā)現(xiàn)氮氣和較少量的氧氣,因為抽取填埋場沼氣時,填埋場形成負(fù)壓,容易導(dǎo)致空氣進(jìn)人填埋場。氧氣和沼氣中的甲烷會形成易燃易爆的混合氣體,因此沼氣脫硫設(shè)備應(yīng)謹(jǐn)慎控制氧氣含量。
Biogas is produced under anaerobic conditions, oxygen and nitrogen generally do not exist in biogas, but if air enters the system from outside, oxygen and nitrogen may be found. If there is oxygen in the biogas, it will be slowly consumed. The presence of nitrogen indicates that denitrification exists in the biogas fermentation process, or leakage occurs in the reactor. It is easier to find nitrogen and a small amount of oxygen in the landfill gas, because when the landfill gas is extracted, the negative pressure will be formed in the landfill site, which will easily lead to air entering the landfill site. Oxygen and methane in biogas will form flammable and explosive gas mixture. Therefore, methane desulfurization equipment should carefully control the oxygen content.
2、二氧化碳
2. Carbon dioxide
二氧化碳是沼氣中只次于甲烷的主要成分。不同類型的底物在發(fā)酵產(chǎn)沼氣過程中都會產(chǎn)生二氧化碳。底物轉(zhuǎn)化生成沼氣是一個復(fù)雜的過程,涉及多個階段和不同類型的微生物菌樣,二氧化碳可形成于不同的階段。在產(chǎn)甲烷階段,二氧化碳作為電子受體,也可被轉(zhuǎn)化成甲烷。
Carbon dioxide is the main component of biogas only inferior to methane. Different types of substrates will produce carbon dioxide in the process of biogas production. Biogas production from substrate is a complex process, involving multiple stages and different types of microbial samples. Carbon dioxide can be formed in different stages. In the methanogenesis stage, carbon dioxide, as an electron acceptor, can also be converted into methane.
二氧化碳會減低沼氣熱值,如果需要增加沼氣熱值(如用作車用燃?xì)饣虿⑷胩烊粴夤芫W(wǎng)),應(yīng)分離除去二氧化碳。沼氣作為其他用途,例如,沼氣發(fā)電或集中供氣,沼氣含有二氧化碳不會有大的問題,但是,二氧化碳溶于冷凝水形成碳酸,對管道和沼氣脫硫設(shè)備有預(yù)定的腐蝕。
Carbon dioxide will reduce the calorific value of biogas. If it is necessary to increase the calorific value of biogas (such as being used as vehicle fuel gas or incorporated into natural gas pipe network), carbon dioxide should be separated and removed. Biogas is used for other purposes, such as biogas power generation or centralized gas supply. There will be no big problem if biogas contains carbon dioxide. However, carbon dioxide dissolves in condensate water to form carbonic acid, which will cause predetermined corrosion to pipelines and biogas desulfurization equipment.
3、水
3. Water
在沼氣發(fā)酵過程中,由于蒸發(fā)作用,沼氣中存在一些量的水分,未經(jīng)處理的沼氣通常含有飽和水蒸氣,其含量與溫度有關(guān)。沼氣中的水分會引起后續(xù)利用一系列問題,例如,水和二氧化碳等混合后形成碳酸溶液腐蝕管道。
In the process of biogas fermentation, due to evaporation, there is a certain amount of moisture in biogas. Untreated biogas usually contains saturated steam, and its content is related to temperature. The moisture in biogas will cause a series of problems in subsequent utilization, such as the formation of carbonic acid solution after water and carbon dioxide are mixed to corrode the pipeline.
另外,水會減低沼氣熱值進(jìn)而影響沼氣利用。根據(jù)燃燒階段的溫度和壓力,冷凝水會造成熱交換器和排氣部件堵塞。
In addition, water will reduce the calorific value of biogas, thus affecting the utilization of biogas. Depending on the temperature and pressure of the combustion phase, condensate can cause blockage of the heat exchanger and exhaust components.
4、氨是沼氣中常見的雜質(zhì)氣體,氨來源于養(yǎng)殖廢水、屠宰廢水以及奶制品廢水的蛋白質(zhì)水解過程,沼氣發(fā)酵過程氨氮過高會抵御產(chǎn)甲燒過程。
4. Ammonia is a common impurity gas in biogas. Ammonia comes from the protein hydrolysis process of breeding wastewater, slaughtering wastewater and dairy wastewater. Too high ammonia nitrogen in biogas fermentation process will resist the process of nail production.
5、顆粒物
5. Particulate matter
顆粒物作為水凝結(jié)的核,常出現(xiàn)在沼氣中。由于其摩擦性能,顆粒物易造成沼氣脫硫設(shè)備的磨損。
As the core of water condensation, particles often appear in biogas. Due to its friction performance, particles are easy to cause wear of biogas desulfurization equipment.