有機(jī)廢棄物資源化利用的過(guò)程中被厭氧處理后,產(chǎn)生的沼氣中含有多種氣體,其中的CH4是非常好的清潔能源,但H2S卻是一種具有惡臭的腐蝕性氣體,對(duì)后續(xù)的管道、沼氣柜、燃?xì)馊紵O(shè)備等都具有很強(qiáng)的腐蝕性,且H2S燃燒后產(chǎn)生SO2濃度很高,對(duì)自然環(huán)境的污染十分嚴(yán)重。因此,沼氣在利用之前都需去除沼氣中的H2S,避免對(duì)后期設(shè)備的腐蝕。
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,承建國(guó)內(nèi)多個(gè)沼氣脫硫項(xiàng)目,并針對(duì)項(xiàng)目中客戶的沼氣的氣量、成分及用途,設(shè)計(jì)出符合客戶需求的干法化學(xué)脫硫、酸法生物脫硫、堿法生物脫硫、絡(luò)合鐵脫硫等脫硫工藝,從設(shè)計(jì)、施工、運(yùn)行等多角度出發(fā)為客戶提供具有針對(duì)性的解決方案。
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堿法生物脫硫
01 alkaline biological desulfurization
堿法生物脫硫過(guò)程分為兩步:
The basic biological desulfurization process is divided into two steps
一步:沼氣通過(guò)脫硫反應(yīng)塔將沼氣中H2S從氣相轉(zhuǎn)化成液相。脫硫反應(yīng)塔就是一個(gè)洗滌塔,沼氣從塔底部進(jìn)入并穿過(guò)濾料床。微堿性循環(huán)水從塔頂進(jìn)入,經(jīng)過(guò)噴頭打散,自由落體穿過(guò)濾床,濾料可以使沼氣與循環(huán)水進(jìn)一步打散和延長(zhǎng)接觸時(shí)間,提高洗滌效果。含有硫化物的循環(huán)水從脫硫反應(yīng)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.
脫硫反應(yīng)塔內(nèi)的化學(xué)方程式:H2S(G)+OH-→HS(L)+H2O
Chemical equation in desulfurization reaction tower: H2S (g) + OH - → HS (L) + H2O
二步:再生池完成循環(huán)水中硫化物被氧化的過(guò)程,循環(huán)水中有大量的脫硫菌(主要為無(wú)色硫細(xì)菌等)將以硫化物為食,把硫化物轉(zhuǎn)化為自身的營(yíng)養(yǎng)物質(zhì),進(jìn)入微生物的自身循環(huán)過(guò)程,從細(xì)菌體內(nèi)排出單質(zhì)硫和氫氧根,從而達(dá)到降解的目的。再生池內(nèi)創(chuàng)造循環(huán)水中脫硫菌的生存環(huán)境,再生池內(nèi)的換熱器給循環(huán)水提供熱量,保證循環(huán)水溫度在33-34度左右。曝氣頭給循環(huán)水提供氧氣,保證循環(huán)水適當(dāng)?shù)娜芙庋?。脫硫菌通過(guò)消化循環(huán)水中的硫化物新陳代謝產(chǎn)生副產(chǎn)品單質(zhì)硫和硫酸根(約占5%),硫酸根會(huì)導(dǎo)致循環(huán)水的pH值降低,還需通過(guò)加藥系統(tǒng)適當(dāng)增加一些堿液中和這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.
再生池內(nèi)的化學(xué)方程式:HS(L)+1/2O2→S+OH-
Chemical equation in regeneration tank: HS (L) + 1 / 2O2 → S + Oh-
這兩步對(duì)沼氣脫硫系統(tǒng)都非常重要。
These two steps are very important for biogas desulfurization system.
一步,H2S得到去除,同時(shí)消耗OH-,
In one step, H2S is removed and oh - is consumed,
二步,在再生池內(nèi)通過(guò)脫硫菌的作用,將硫化物氧化生成單質(zhì)硫,OH-重新生成。單質(zhì)硫經(jīng)沉淀池沉淀從底部排出硫污泥,沉淀池的上清液回到循環(huán)水系統(tǒng)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.
項(xiàng)目案例:
Project case:
02酸法生物脫硫
02 acid biological desulfurization
酸法生物脫硫過(guò)程分為三步:
The process of acid biological desulfurization is divided into three steps
一步:沼氣穿過(guò)脫硫反應(yīng)器,反應(yīng)器中裝有濾料,濾料表面覆蓋有水層,沼氣中的化學(xué)物質(zhì)與濾料接觸后在表層溶解,并從氣相轉(zhuǎn)化為液相,以利于濾料中的細(xì)胞作進(jìn)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:水溶液中的異味成分被微生物吸附吸收,H2S從水中轉(zhuǎn)移微生物體內(nèi)。
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:濾料中的專性細(xì)菌(主要為氧化亞鐵硫桿菌、脫氮硫桿菌、排硫硫桿菌、氧化硫硫桿菌)將以污染物為食,把污染物轉(zhuǎn)化為自身的營(yíng)養(yǎng)物質(zhì),使H2S從化合物的形式轉(zhuǎn)化為游離態(tài),進(jìn)入微生物的自身循環(huán)過(guò)程,從而達(dá)到降解的目的。與此同時(shí),專性細(xì)菌等微生物又可實(shí)現(xiàn)自身的繁殖過(guò)程,當(dāng)作為食物的污染化合物與專性細(xì)菌的營(yíng)養(yǎng)需要達(dá)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.
脫硫:2H2S+O2→2S+2H2O
Desulfurization: 2h2s + O2 → 2S + 2H2O
再生:2S+3O2+2H2O→2H2SO4
Regeneration: 2S + 3O2 + 2H2O → 2h2so4
沼氣堿法、酸法生物脫硫是自主研發(fā)且具有成熟脫硫技術(shù),即利用脫硫微生物的再生作用,通過(guò)控制生化反應(yīng)條件,將沼氣中的H2S轉(zhuǎn)化成為單質(zhì)S或硫酸鹽,從而實(shí)現(xiàn)去除H2S的目的。利用該技術(shù),在項(xiàng)目運(yùn)行的過(guò)程中,僅需要適當(dāng)添加微量的營(yíng)養(yǎng)鹽和堿,以保證微生物的活性,即可提高脫硫效率,是一種非常經(jīng)濟(jì)穩(wěn)定的沼氣脫硫技術(shù)。
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.