Patent ID: 7824472
Filing Date: 2010-11-02
Classification: B01D,C01B

Abstract:
1. A pressure swing adsorption method in which a mixture gas containing at least two main components is used as a material gas, an adsorbent which easily adsorbs at least one main component in the material gas and does not readily adsorb at least another main component in the material gas is used, the method uses a separation apparatus comprising a lower column and a upper column which are filled with the adsorbent, a material gas storage tank for storing the material gas to be introduced into the lower column, a strong adsorbate storage tank for storing a main component which is easily adsorbed by the adsorbent, and a compressor for pressurizing gas from the material gas storage tank or the strong adsorbate storage tank and introducing into the lower column, and the strong adsorbate which is easily adsorbed by the adsorbent and the weak adsorbate which is not readily adsorbed by the adsorbent are recovered, wherein the method comprises: a step (a) in which the gas in the material gas storage tank is pressurized and introduced into the lower column, the strong adsorbate in the material gas is adsorbed by the adsorbent, gas from the lower column which contains a less amount of the strong adsorbate is introduced into the upper column, the strong adsorbate contained in the gas is adsorbed by the adsorbent in the upper column, and the weak adsorbate which flows from the upper column is recovered; a step (b) in which the gas in the strong adsorbate storage tank is pressurized by the compressor and introduced into the lower column, the weak adsorbate co-adsorbed by the adsorbent in the lower column and the weak adsorbate remaining in space among the adsorbent are led into the upper column, the strong adsorbate contained in the gas led out from the lower column is adsorbed by the adsorbent in the upper column, and the weak adsorbate which flows from the upper column is recovered; a step (c) in which the lower column is depressurized, the strong adsorbate adsorbed by the adsorbent filled in the lower column is desorbed, and the desorbed strong adsorbate is recovered in the strong adsorbate storage tank; a step (d) in which the upper column is depressurized, the weak adsorbate adsorbed by the adsorbent in the upper column is desorbed, the desorbed gas is introduced into the lower column, and gas which flows from the lower column is recovered in the material gas storage tank; and a step (e) in which the weak adsorbate recovered in the steps (a) and (b) is introduced into the upper column as a counter current purge gas, the strong adsorbate adsorbed by the adsorbent in the upper column is displaced and desorbed, gas which flows from the upper column is introduced into the lower column, the strong adsorbate adsorbed by the adsorbent in the lower column is displaced and desorbed by the gas introduced into the lower column, and gas which flows from the lower column is recovered in the material gas storage tank; and these steps (a) to (e) are sequentially repeated based on a predetermined sequence, and the strong adsorbate and the weak adsorbate in the material gas are simultaneously recovered in a high concentration with a high recovery percentage.