The main components of biogas are CH4 and CO2, and the high-purity methane gas obtained by separating CO2 from the mixed gas is called biological natural gas. Biological natural gas can be directly used as an alternative fuel for petrochemical natural gas. The increasing demand for natural gas by humans has driven the development of bio natural gas technology. This article analyzes the differences in characteristics between biogas and natural gas, as well as the possibility of biogas purification replacing natural gas. It reviews the progress of methods for biogas purification, including pressurized water washing, chemical absorption, pressure swing adsorption (PSA), membrane separation, low-temperature separation, and in-situ methane enrichment, Among them, the pressurized water washing method and PSA method have become the two most commercially available technologies due to their comprehensive advantages in technology and economy. The performance of membrane separation technology in reducing purification costs and simplifying purification systems makes it a promising technology for development. Methane in-situ enrichment technology has advantages in using high solid content raw materials to produce biological natural gas.
