EFFICIENT OBTAINMENT OF UNADSORBED GAS FROM GAS CONTAINING UNADSORBED GAS OF LOW CONCENTRATION

摘要

PURPOSE:To contrive the improvement of efficiency in adsorbing an unadsorbed gas and the recovery of a gas of high concn. even from an untreated gas of lower concn. by adsorbing adesorbed gas introduced from a second adsorption tower into an adsorption tower after adsorption treatment and effecting its desorption treatment. CONSTITUTION:The gas contg. an unadsorbed gas of lower concn. is subjected to an adsorption and desorption treatment in adsorption towers 1 and 2 filled with an adsorptive substance and the exhaust desorbed gas contg. an unadsorbed gas of higher concn. is condensed. At this time, the desorption treatment is effected after the adsorption of an unadsorbed gas contained in the desorbed gas introduced from a second adsorption tower 3 described later into the adsorption tower after the adsorption treatment. The exhaust gas contg. the uncondensed, unadsorbed gas resulting from the condensation of the desorbed gas is introduced into the adsorption tower 3 to adsorb the unadsorbed gas contained therein. In the next adsorption and desorption process, the desorption treatment in the adsorption tower 3 is effected and the resulting desorbed gas contg. the unadsorbed gas is adsorbed, followed by its introduction into the adsorption tower.