Biogas is the product of anaerobic fermentation of biomass. It is a kind of high-quality renewable biomass energy. The main components are CH4 (about 55% - 70%) CO2 (about 30% - 45%), and a small amount of H2S, O2, Co, N2 and other hydrocarbons. The CO2 in biogas reduces the energy density and calorific value of biogas, and limits the utilization range of biogas, It is necessary to decarbonize and purify biogas to reduce the content of CO2.
The technology of biogas purification mainly includes the following aspects: 1. Membrane separation is an energy-saving CO2 separation and recovery process which has developed rapidly in recent years. This method uses the different solubility and permeability of different components in biogas when passing through the membrane to realize the separation of biogas. 2. Chemical absorption method is to use weak alkaline absorption liquid to absorb acidic CO2 in the adsorption tower, and then enter the desorption tower to complete regeneration under high temperature conditions, so as to achieve the purpose of removing CO2 from biogas. 3. Water washing method is to realize the separation of CO2 and CH4 by physical absorption based on the different solubility of CO2 and CH4 in water. 4. The adsorption principle of PSA is to selectively adsorb CO2 in biogas to separate it from CH4 by using adsorbents with different adsorption capacity for CH4 and CO2. 5. Low temperature separation method is to use the different boiling points of CH4 and CO2 to convert CO2 in biogas into liquid or solid at low temperature, but CH4 remains in gas state, so as to realize the separation of the two.
There are many biogas purification technologies. Kaifeng DEAR Air Separation Co., Ltd. has mature biogas purification technology and experience, which can be designed and selected according to users' energy utilization goals.
