New technique for concentrating methane in oxygen-containing coal bed gas

The invention discloses a new technique for concentrating methane in oxygen-containing coal bed gas. Different adsorbents and different technological processes are adopted according to different concentrations of methane in the oxygen-containing coal bed gas, when concentration of methane in the oxygen-containing coal bed gas is low, a three-stage technological process is adopted, namely a first stage of low pressure methane enrichment technological process, a second stage of pressurized adsorption deoxygenation technological process, and a third stage of methane concentration technological process; when the concentration of the methane in the oxygen-containing coal bed gas is high, a two-stage technological process is adopted, namely a first stage of pressurized adsorption deoxygenation technological process and a second stage of methane concentration technological process, and 2-12 towers are arranged during an adsorption process. By adopting the new technique for concentrating the methane in the oxygen-containing coal bed gas, concentration of CH4 in the oxygen-containing coal bed gas can be increased to be more than 90%, O2 content can be reduced to be less than 0.5%, and a corresponding multi-stage concentrating way and a corresponding adsorbent are adopted in a concentrating process, so that technical defects in the prior art that PSA (polysulfone amide) is adopted for concentrating CH4 in the oxygen-containing coal bed gas are overcome.