Process and apparatus for separating constituents of a gas mixture by adsorption

A process for separating a gas mixture composed of a plurality of gaseous constituents into separate gaseous constituents by adsorption within an enclosure, the enclosure having defined therein a plurality of compartments which are equal in size, sequentially arranged, separated from one another, and gas tight, which are each provided with an adsorbent material preselected as a function of which of the plurality of gaseous constituents is to be separated, and which are each arranged for temporarily allowing introduction of a gas mixture to be separated and for evacuation of at least one preselected gaseous constituent of the gas mixture whilst the adsorbent material adsorbs at least one not preselected gaseous constituent of the gas mixture to be separated, the process comprising:

• a. as adsorption steps:
• (1) introducing the gas mixture to be separated into one of the plurality of compartments until a predetermined pressure is reached while in further compartments of the plurality of compartments, consecutively starting from a compartment which is closest to the compartment where the gas is introduced in step a. (1);
• and
• (2) introducing the gas mixture to be separated into at least one compartment and allowing the at least one preselected constituent to escape therefrom;
• b. as desorption steps:
• (1) allowing pressure in a next compartment to drop so as to obtain naturally a partial desorption of the at least one not preselected gaseous constituent and optionally subsequently subjecting the next compartment, in view of said partial desorption, to a partial vacuum;
• (2) subjecting at least a next additional compartment to a final desorption vacuum which is equal to or stronger than the partial vacuum for the partial desorption;
• and
• (3) injecting a purging fluid into a last compartment to achieve a final desorption of the at least one not preselected constituent and substantially maintaining the final desorption vacuum therein during injection of the purging fluid;
• and
• c. providing between the compartment of step b (3) into which the purging fluid is injected and which is subjected to the final desorption vacuum, and the compartment of step a (1) wherein the gas mixture to be separated is introduced up to a predetermined pressure, an additional compartment wherein the gas mixture to be separated is let in naturally, by natural aspiration, whereby the vacuum prevailing therein after vacuum purging in step b (3) is compensated.