Separation method of CO gas not containing CH_4

摘要

It is an object of the present invention to provide a method for separating CO gas substantially free of CH₄ while maintaining the CO gas recovery rate. The CO gas is supplied by a four- tower pressure swing adsorption method from a source gas consisting of H₂, CO, CH₄, CO₂, and H₂O. Is a method of separating and recovering the H 2 gas by supplying the raw material gas to the adsorption tower, and simultaneously adsorbing CH, CO 2, and H 2 O, and depressurizing the inside of the electric adsorption column in the same direction as the adsorption step. The decompression process of boosting the CO gas containing CH2 gas to recover the H2 gas, and then finally discharging the CO gas, mixing the raw material gas and supplying it to the adsorption tower, and partially absorbing the recovered H2 gas. Fiji process for desorption and removal of CO2, CH₄ and CO gas from the adsorption tower by supplying in the reverse direction of the process, and boosting the pressure inside the electrosorption tower as part of the electricity recovery H2 gas. It is carried out repeatedly in this order in the adsorption tower of the four step-up process, in order thereof. It is possible to separate CO having a CH₄ content of 20 ppm or less while preventing a decrease in the CO gas recovery rate.