（1）化学吸收。一种化学吸收机理是采用胺、碱、醇等复合溶液吸收剂，利用酸碱中和反应吸收沼气中的CO2、H2S等酸性物质，同时也能吸收NH3等易溶于水、醇的气体。另一种化学吸收机理是采用干化学物质（如Fe2O3）作为吸收剂吸收杂质气体。化学吸收的吸收剂都可以通过装置的自净系统和再生系统释放出各种杂质和气体得到再生循环使用。
(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）物理提纯。通过此机理提纯沼气的主要是变压吸附法。利用吸附剂在不同压力条件下对不同气体吸附力不同的原理来分离沼气中的不同组份。沼气中的H2O、CO2、H2S等吸附容量较大的强吸附组分在一定压力下被吸附剂吸附停留在床层中，而较小吸附容量的弱吸附组分N2、CH4 等从床层出口输出，从而实现了对沼气的提纯。

(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）生物脱除。在一定的条件下利用微生物生长繁殖需要沼气中某些杂质气体作为营养物质，从而实现对沼气的提纯。
(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.
现阶段，物理化学法已被广泛地应用且积累了丰富的经验。但该方法存在运行费用高、投资大、再生困难、产生二次污染等缺点。生物法具有不需催化剂和氧化剂、不需处理化学污泥、少污染、低能耗、高效率、可回收单质硫等优点，正在成为yl6809永利领域的发展趋势。
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.