Patent ID: 8545601

Claim:
A two-stage complete recycle pressure-swing adsorption process for gas Separation, wherein the process is used to separate the strongly adsorbed component and the weakly adsorbed component from the gas mixture; the process adopts two-stage pressure-swing adsorption device operating in series; the gas mixture is fed into the first stage pressure-swing adsorption device, and the strongly adsorbed component of the gas mixture is adsorbed and is concentrated as product; the interim gas mixture from the outlet of the adsorption tower of the first stage pressure-swing adsorption device is fed into the second stage pressure-swing adsorption device; the strongly adsorbed component in the interim gas mixture is adsorbed further, and the nonadsorbed weakly adsorbed component acts as product and is fed into next step; all of the gas excepting for the weakly adsorbed component entering into next step in the second stage is returned into the first stage to increase the pressure of the adsorption tower; the adsorption tower of the first stage sequentially undergoes the following steps in one circulation period: adsorption step A, two-end equalization depressurization 2 ED′, backward depressurization BD, second stage gas repressurization 2 ER, two-end equalization repressurization 2 ER′ and final repressurization FR; the adsorption tower of the second stage sequentially undergoes the following steps in one circulation period: adsorption A, cocurrent equalization depressurization ED, backward depressurization BD, backward equalization repressurization ER and final repressurization FR, wherein during said two-end equalization depressurization step, the gas discharged at different times from both the inlet and the outlet of the adsorption tower enters into the adsorption tower which has completed the first stage regeneration step to pressurize, wherein the outlet of the depressurization adsorption tower is connected to the outlet of the pressurization adsorption tower that has been purged; and the inlet of the depressurization adsorption tower is connected to the inlet of the pressurization adsorption tower that has been purged.