PURPOSE: To reduce the amount of product gas to be used as washing gas and to obtain the product gas with improved purity.
CONSTITUTION: In a pressure variable adsorption method which has adsorption towers 10, 11 filled with an adsorbent and comprises an adsorption process in which product gas is selectively adsorbed by the adsorbent from pressurized mixed gas, a washing process in which unnecessary gas is removed using a part of the product gas, and a desorption process in which the product gas adsorbed by the adsorbent is recovered by reducing the pressure, an automatic valve 10G is installed at the top of the adsorption tower, and the adsorption towers 10, 11 are separated from their pipe headers by closing the valve 10G at the start of the desorption process to reduce the volume of a space at the top of the tower.
KAWAMURA YASUSHI
KOSUGE KATSUSHI
KATO YUZURU
