Pressure equalizing processes in vacuum pressure-swing adsorption for upgrading methane in coal mine gas

The effect of pressure equalizing processes in vacuum pressure-swing adsorption on concentrating the methane in coal mine gas was studied experimentally.The results show that pressure equalization can increase the pressure of the absorber rapidly,and raise the adsorption pressure and methane content.The optimal pressure equalizing process is equalizing the pressure at both the inlet and outlet ends of the absorber.After pressure equalization at the inlet end for 0.2s and the outlet end for 0.4s,the methane concentration of the desorbed gas reaches maximum.In the meantime there is still a pressure difference between two absorbers.The energy consumption of raising the pressure from different equalizing pressures to a certain adsorption pressure was analyzed.The energy consumption is decreased by 31% when the equalizing pressure increases from 93.8kPa to 120.4kPa.