Patent ID: 7300497

Claim:
A gas separation method which uses a pressure swing adsorption method to separate from a mixed gas containing at least two components, a first component and a second component, using a first adsorbable column containing a first adsorbent on which said first component is less readily adsorbable and said second component is more readily absorbable, and a second adsorption column containing a second adsorbent on which said first component is more readily adsorbable and said second component is less readily adsorbable, comprising: a first step comprising an adsorption step in which in said first adsorption column, said mixed gas is supplied at a high pressure and said second component is selectively adsorbed and said first component is separated as a first product gas, and a regeneration step in which in said second adsorption column, said first component is desorbed by depressurization; a second step comprising an equalization depressurization step in which said first adsorption column is depressurized by connecting said first adsorption column and said second adsorption column, and introducing the gas in said first adsorption column into said second adsorption column, to pressure equalize said first and second adsorption columns, and an equalization pressurization step in which said second adsorption column is pressurized to equalize the pressure of said first and second adsorption columns; a third step comprising a regeneration step in which in said first adsorption column, said second component is desorbed by depressurization, and an adsorption step in which in said second adsorption column, said mixed gas is supplied at a high pressure, and said first component is selectively adsorbed, and said second component is separated as a second product gas; and a fourth step comprising an equalization depressurization step in which said second adsorption column is depressurized by connecting said second adsorption column and said first adsorption column, and introducing the gas in said second adsorption column into said first adsorption column, to pressure equalize said first and second adsorption columns, and an equalization pressurization step in which said first adsorption column is pressurized to equalize the pressure of said first and second adsorption columns, wherein a first product gas storage tank that stores said first product gas and a second product gas storage tank that stores said second product gas are used, and in said regeneration step in said first and second adsorption columns, each product gas in said first and the second product gas storage tanks is introduced into said first and the second adsorption columns respectively, and in said equalization pressurization step in said first and second adsorption columns, each product gas in said first and the second product gas storage tanks is introduced into said first and second adsorption columns respectively.