（1）化學(xué)吸收。一種化學(xué)吸收機(jī)理是采用胺、堿、醇等復(fù)合溶液吸收劑，利用酸堿中和反應(yīng)吸收沼氣中的CO2、H2S等酸性物質(zhì)，同時也能吸收NH3等易溶于水、醇的氣體。另一種化學(xué)吸收機(jī)理是采用干化學(xué)物質(zhì)（如Fe2O3）作為吸收劑吸收雜質(zhì)氣體。化學(xué)吸收的吸收劑都可以通過裝置的自凈系統(tǒng)和再生系統(tǒng)釋放出各種雜質(zhì)和氣體得到再生循環(huán)使用。
(1) Chemical absorption. One chemical absorption mechanism is to use amine, alkali, alcohol and other composite solution absorbers to absorb CO2, H2S and other acidic substances in biogas by acid-base neutralization reaction. At the same time, it can also absorb NH3 and other gases easily soluble in water and alcohol. The other chemical absorption mechanism is to use dry chemical substances (such as Fe2O3) absorbs impurity gas as absorbent. The chemically absorbed absorbent can release various impurities and gases through the self purification system and regeneration system of the device for regeneration and recycling.
（2）物理提純。通過此機(jī)理提純沼氣的主要是變壓吸附法。利用吸附劑在不同壓力條件下對不同氣體吸附力不同的原理來分離沼氣中的不同組份。沼氣中的H2O、CO2、H2S等吸附容量較大的強(qiáng)吸附組分在一定壓力下被吸附劑吸附停留在床層中，而較小吸附容量的弱吸附組分N2、CH4 等從床層出口輸出，從而實現(xiàn)了對沼氣的提純。

(2) Physical purification. Pressure swing adsorption is the main method to purify biogas through this mechanism. Different components in biogas are separated by using the principle that adsorbents have different adsorption capacity for different gases under different pressure conditions. Strong adsorption components with large adsorption capacity such as H2O, CO2 and H2S in biogas are adsorbed by adsorbents under certain pressure and stay in the bed, while weak adsorption with small adsorption capacity The components N2 and CH4 are output from the bed outlet, so as to realize the purification of biogas.
（3）生物脫除。在一定的條件下利用微生物生長繁殖需要沼氣中某些雜質(zhì)氣體作為營養(yǎng)物質(zhì)，從而實現(xiàn)對沼氣的提純。
(3) Biological removal. Under certain conditions, the use of microbial growth and reproduction requires some impurity gases in biogas as as nutrients, so as to realize the purification of biogas.
現(xiàn)階段，物理化學(xué)法已被廣泛地應(yīng)用且積累了豐富的經(jīng)驗。但該方法存在運(yùn)行費(fèi)用高、投資大、再生困難、產(chǎn)生二次污染等缺點(diǎn)。生物法具有不需催化劑和氧化劑、不需處理化學(xué)污泥、少污染、低能耗、高效率、可回收單質(zhì)硫等優(yōu)點(diǎn)，正在成為沼氣脫硫領(lǐng)域的發(fā)展趨勢。
At present, physicochemical methods have been widely used and accumulated rich experience. However, this method has some disadvantages, such as high operation cost, large investment, difficult regeneration, secondary pollution and so on. Biological method has the advantages of no catalyst and oxidant, no treatment of chemical sludge, less pollution, low energy consumption, high efficiency and recyclable elemental sulfur. It is becoming the development trend in the field of biogas desulfurization.