有机废弃物资源化利用的过程中被厌氧处理后,产生的沼气中含有多种气体,其中的CH4是非常好的清洁能源,但H2S却是一种具有恶臭的腐蚀性气体,对后续的管道、沼气柜、燃气燃烧设备等都具有很强的腐蚀性,且H2S燃烧后产生SO2浓度很高,对自然环境的污染十分严重。因此,沼气在利用之前都需去除沼气中的H2S,避免对后期设备的腐蚀。
After anaerobic treatment in the process of resource utilization of organic waste, the biogas produced contains a variety of gases, among which CH4 is a very good clean energy, However, H2S is a kind of malodorous corrosive gas, which has strong corrosivity to the following pipelines, biogas tanks, gas combustion equipment, etc., and the concentration of SO2 produced by the combustion of H2S is very high, which seriously pollutes the natural environment. Therefore, before the utilization of biogas, it is necessary to remove the H2S in biogas to avoid the corrosion of later equipment.
目前,承建国内多个沼气脱硫项目,并针对项目中客户的沼气的气量、成分及用途,设计出符合客户需求的干法化学脱硫、酸法生物脱硫、碱法生物脱硫、络合铁脱硫等脱硫工艺,从设计、施工、运行等多角度出发为客户提供具有针对性的解决方案。
At present, we have undertaken a number of domestic biogas desulfurization projects. According to the gas volume, composition and use of biogas in the project, we have designed desulfurization processes that meet the needs of customers, such as dry chemical desulfurization, acid biological desulfurization, alkali biological desulfurization, complex iron desulfurization, etc., and provided targeted solutions for customers from the perspectives of design, construction and operation.
01碱法生物脱硫
01 alkaline biological desulfurization
碱法生物脱硫过程分为两步:
The basic biological desulfurization process is divided into two steps
一步:沼气通过脱硫反应塔将沼气中H2S从气相转化成液相。脱硫反应塔就是一个洗涤塔,沼气从塔底部进入并穿过滤料床。微碱性循环水从塔顶进入,经过喷头打散,自由落体穿过滤床,滤料可以使沼气与循环水进一步打散和延长接触时间,提高洗涤效果。含有硫化物的循环水从脱硫反应塔底部流入再生池。
One step: the methane is converted from gas phase to liquid phase by desulfurization reaction tower. Desulfurization reaction tower is a washing tower, biogas enters from the bottom of the tower and passes through the filter bed. The micro alkaline circulating water enters from the top of the tower, disperses through the nozzle, and freely falls through the filter bed. The filter material can further disperse the biogas and the circulating water, prolong the contact time, and improve the washing effect. The circulating water containing sulfide flows into the regeneration tank from the bottom of desulfurization reaction tower.
脱硫反应塔内的化学方程式:H2S(G)+OH-→HS(L)+H2O
Chemical equation in desulfurization reaction tower: H2S (g) + OH - → HS (L) + H2O
二步:再生池完成循环水中硫化物被氧化的过程,循环水中有大量的脱硫菌(主要为无色硫细菌等)将以硫化物为食,把硫化物转化为自身的营养物质,进入微生物的自身循环过程,从细菌体内排出单质硫和氢氧根,从而达到降解的目的。再生池内创造循环水中脱硫菌的生存环境,再生池内的换热器给循环水提供热量,保证循环水温度在33-34度左右。曝气头给循环水提供氧气,保证循环水适当的溶解氧。脱硫菌通过消化循环水中的硫化物新陈代谢产生副产品单质硫和硫酸根(约占5%),硫酸根会导致循环水的pH值降低,还需通过加药系统适当增加一些碱液中和这5%的硫酸根。
The second step: the regeneration pool completes the process of sulfide oxidation in the circulating water. A large number of desulfurization bacteria (mainly colorless sulfur bacteria, etc.) in the circulating water will feed on the sulfide, convert the sulfide into their own nutrients, enter the microbial self circulation process, and discharge elemental sulfur and hydroxyl from the bacteria, so as to achieve the purpose of degradation. The heat exchanger in the regeneration pool provides heat for the circulating water to ensure that the temperature of the circulating water is about 33-34 ℃. The aeration head provides oxygen for the circulating water to ensure proper dissolved oxygen in the circulating water. By digesting sulfide in circulating water, desulfurizing bacteria produce elemental sulfur and sulfate (about 5%). Sulfate will reduce pH value of circulating water, and it is necessary to add some alkali liquor to neutralize the 5% sulfate through dosing system.
再生池内的化学方程式:HS(L)+1/2O2→S+OH-
Chemical equation in regeneration tank: HS (L) + 1 / 2O2 → S + Oh-
这两步对沼气脱硫系统都非常重要。
These two steps are very important for biogas desulfurization system.
一步,H2S得到去除,同时消耗OH-,
In one step, H2S is removed and oh - is consumed,
二步,在再生池内通过脱硫菌的作用,将硫化物氧化生成单质硫,OH-重新生成。单质硫经沉淀池沉淀从底部排出硫污泥,沉淀池的上清液回到循环水系统中。
In the second step, sulfide is oxidized to elemental sulfur by desulfurizing bacteria in the regeneration tank, and oh - is regenerated. The elemental sulfur is precipitated by the sedimentation tank, and the sulfur sludge is discharged from the bottom, and the supernatant of the sedimentation tank returns to the circulating water system.
项目案例:
Project case:
02酸法生物脱硫
02 acid biological desulfurization
酸法生物脱硫过程分为三步:
The process of acid biological desulfurization is divided into three steps
一步:沼气穿过脱硫反应器,反应器中装有滤料,滤料表面覆盖有水层,沼气中的化学物质与滤料接触后在表层溶解,并从气相转化为液相,以利于滤料中的细胞作进一步的吸收和分解。
One step: the biogas passes through the desulfurization reactor, in which the filter material is installed, and the surface of the filter material is covered with water layer. After contacting with the filter material, the chemical substance in the biogas dissolves in the surface layer, and transforms from the gas phase to the liquid phase, so as to facilitate the further absorption and decomposition of the cells in the filter material.
二步:水溶液中的异味成分被微生物吸附吸收,H2S从水中转移至微生物体内。
Second step: the odor components in the aqueous solution are absorbed by microorganisms, and H2S is transferred from the water to the microorganisms.
三步:滤料中的专性细菌(主要为氧化亚铁硫杆菌、脱氮硫杆菌、排硫硫杆菌、氧化硫硫杆菌)将以污染物为食,把污染物转化为自身的营养物质,使H2S从化合物的形式转化为游离态,进入微生物的自身循环过程,从而达到降解的目的。与此同时,专性细菌等微生物又可实现自身的繁殖过程,当作为食物的污染化合物与专性细菌的营养需要达到平衡。
Three steps: the specific bacteria (mainly Thiobacillus ferrooxidans, Thiobacillus denitrificans, Thiobacillus thiooxidans, Thiobacillus thiooxidans) in the filter media will feed on the pollutants, transform the pollutants into their own nutrients, make the H2S from the form of compounds into free state, enter the self circulation process of microorganisms, so as to achieve the purpose of degradation. At the same time, obligate bacteria and other microorganisms can achieve their own reproduction process, when the food pollution compounds and obligate bacteria nutrition needs to achieve a balance.
脱硫:2H2S+O2→2S+2H2O
Desulfurization: 2h2s + O2 → 2S + 2H2O
再生:2S+3O2+2H2O→2H2SO4
Regeneration: 2S + 3O2 + 2H2O → 2h2so4
沼气碱法、酸法生物脱硫是自主研发且具有成熟脱硫技术,即利用脱硫微生物的再生作用,通过控制生化反应条件,将沼气中的H2S转化成为单质S或硫酸盐,从而实现去除H2S的目的。利用该技术,在项目运行的过程中,仅需要适当添加微量的营养盐和碱,以保证微生物的活性,即可提高脱硫效率,是一种非常经济稳定的沼气脱硫技术。
Biogas alkali and acid biological desulfurization are self-developed and mature desulfurization technologies, that is, by using the regeneration of desulfurization microorganisms and controlling biochemical reaction conditions, H2S in biogas can be transformed into elemental s or sulfate, so as to achieve the purpose of removing H2S. Using this technology, in the process of project operation, only a small amount of nutrients and alkali need to be added to ensure the activity of microorganisms, which can improve the desulfurization efficiency. It is a very economic and stable biogas desulfurization technology.