目前沼氣提純工藝有變壓吸附法(PSA)、水洗法、化學(xué)吸收法、膜分離法、選擇分離法等,在目前世界范圍內(nèi)工藝較為成熟、應(yīng)用相對(duì)較多的方法是變壓吸附法(PSA)、化學(xué)吸收法(胺法凈化)。下面沼氣提純?cè)O(shè)備廠家就給大家詳細(xì)介紹一下!
Pressure swing adsorption (PSA), water washing, chemical absorption, membrane separation and selective separation are the current purification processes of biogas. Pressure swing adsorption (PSA) and chemical absorption (amine purification) are the most mature and widely used methods in the world. The following biogas purification equipment manufacturers will give you a detailed introduction!
1、變壓吸附法(PSA)
1. Pressure swing adsorption (PSA)
變壓吸附法(PSA)是在加壓條件下,利用沼氣中的CH4、CO2以及N2在吸附劑表面被吸附的能力不同而實(shí)現(xiàn)分離氣體成分的一種方法。組分的吸附量受壓力及溫度的影響,壓力升高時(shí)吸附量增加,壓力降低時(shí)吸附量減少;當(dāng)溫度升高時(shí)吸附量減小,溫度降低時(shí)吸附量增加。變壓吸附對(duì)氣體來(lái)源的要求非常嚴(yán)格,H2S的存在會(huì)導(dǎo)致吸附劑性中毒,并且變壓吸附要求氣體干燥,所以變壓吸附前要先脫除H2S和H2。
Pressure swing adsorption (PSA) is a method to separate gas components under pressure by using different adsorption capacities of CH4, CO2 and N2 in biogas on the surface of adsorbent. The adsorption capacity of components is affected by pressure and temperature. The adsorption capacity increases with the increase of pressure and decreases with the decrease of pressure. The adsorption capacity decreases with the increase of temperature and increases with the decrease of temperature. Pressure swing adsorption (PSA) requires very strict gas sources. The existence of H2S will lead to permanent poisoning of adsorbents. PSA requires gas drying. So H2S and H2 should be removed before PSA.
吸附材料在該技術(shù)中起到關(guān)鍵的作用,一般采用不同類(lèi)型的活性炭、沸石、硅膠、氧化鋁和分子篩作為吸附材料。不同的吸附材料對(duì)沼氣的純化效果各不相同。目前,以活性炭和分子篩為主的碳基吸附劑,在研究沼氣提純方面經(jīng)常被使用。近年來(lái)出現(xiàn)的一些新型吸附材料,如有序介孔材料、胺修飾吸附劑和金屬框架物(MOFs)對(duì)CO2具有很高吸附選擇性,應(yīng)用前景廣闊,而且MOFs被認(rèn)為是在CO2分離方面具有潛力。
Adsorption materials play a key role in this technology. Generally, different types of activated carbon, zeolite, silica gel, alumina and molecular sieve are used as adsorption materials. Different adsorption materials have different purification effects on biogas. At present, carbon-based adsorbents, mainly activated carbon and molecular sieve, are often used in the study of biogas purification. In recent years, some new adsorption materials, such as ordered mesoporous materials, amine-modified adsorbents and metal frameworks (MOFs), have high adsorption selectivity for CO2, and have broad application prospects. MOFs are considered to have potential in CO2 separation.
2、化學(xué)吸收法
2. Chemical Absorption Method
化學(xué)吸收法是利用胺溶液將CO2從CH4中分離的方法,分離過(guò)程中CO2被吸收后進(jìn)一步與胺溶液發(fā)生化學(xué)反應(yīng),通過(guò)加熱完成胺溶液的再生。由于化學(xué)反應(yīng)具有很強(qiáng)的選擇性,而CH4被胺溶液吸收的量又非常低,所以這種方法CH4的損失率低于0.1%。該技術(shù)操作壓力一般為1atm。
Chemical absorption is a method of separating CO2 from CH4 by using amine solution. In the process of separation, CO2 is absorbed and reacted with amine solution further. The regeneration of amine solution is completed by heating. Because of the strong selectivity of chemical reaction and the very low absorption of CH4 by amine solution, the loss rate of CH4 in this method is less than 0.1%. The operating pressure of this technology is generally 1 atm.
常用的胺溶液主要有乙醇胺(MEA)、二乙醇胺(DEA)和甲基二乙醇胺(MDEA)[13]。由于CO2被吸收后與胺溶液發(fā)生了化學(xué)反應(yīng),因此吸收過(guò)程可以在較低的壓力條件下進(jìn)行,一般情況下只需在沼氣已有壓力的基礎(chǔ)上稍微提高一些壓力即可。胺溶液的再生過(guò)程比較困難,需要160℃的溫度條件,因此運(yùn)行過(guò)程需要消耗大量的工藝用熱,存在運(yùn)行能耗高的弊端。此外,由于存在蒸發(fā)損失,運(yùn)行過(guò)程需要經(jīng)常補(bǔ)充胺溶液。
The commonly used amine solutions are ethanolamine (MEA), diethanolamine (DEA) and methyl diethanolamine (MDEA) [13]. Because of the chemical reaction between CO2 and amine solution after absorption, the absorption process can be carried out under lower pressure. Generally, only slightly higher pressure is needed on the basis of the existing pressure of methane. The regeneration process of amine solution is very difficult and needs 160 C temperature. Therefore, the operation process needs to consume a lot of process heat, which has the disadvantage of high energy consumption. In addition, because of the evaporation loss, the ammonia solution needs to be replenished frequently during operation.
Today, Xiaobian will talk to you for a moment. I hope this article can help you. If you have any questions about this, please consult the customer service staff of the biogas purification website: http://www.aycqc.cn.