Pressure swing adsorption process

A pressure swing adsorption process which comprises:

• switching a plurality of adsorption columns packed with an adsorbent successively to an adsorption step, a first pressure equalization step, an evacuation step, a vacuum purge step, a second pressurization equalization step and a repressurization step to allow a more strongly adsorbable component gas contained in a gaseous mixture to be adsorbed on the adsorbent and to separate a less strongly adsorbable component gas;
• and
• compressing the thus separated less strongly adsorbable component gas by a product gas compressor to supply it as a product gas;
• wherein procedures of changing a feed amount of product gas is carried out by inputting a signal for changing the feed amount of product gas:
• a. to control an aperture of a circulatory flow control valve disposed on a circulatory passage connecting a discharge side and inlet side of said product gas compressor to control the amount of gas circulating from the discharge side to the inlet side of said compressor, whereby to control the amount of product gas delivered from said product gas compressor to a product gas feed passage to a preset flow rate after the change;
• and
• b. to control an aperture of a control valve disposed on said product feed passage to a level corresponding to predetermined gas flow conditions.

A pressure swing adsorption process which comprises:

• switching a plurality of adsorption columns packed with an adsorbent successively to an adsorption step, a first pressure equalization step, an evacuation step, a vacuum purge step, a second pressure equalization step and a pressurization step to allow a more strongly adsorbable component gas contained in a gaseous mixture to be adsorbed on the adsorbent and to separate a less strongly adsorbable component gas;
• and
• compressing the thus separated less strongly adsorbable component gas by a product gas compressor to supply it as a product gas;
• wherein procedures of reducing a feed amount of product gas is carried out by inputting a signal for reducing the feed amount of product gas to control an aperture of a flow control valve disposed on a product gas feed passage to a level corresponding to a reduced feed amount of product gas, and upon the feed amount of product gas substantially reaching a level, each step switching timing is changed in accordance with an operational mode corresponding to the reduced feed amount of product gas.

A pressure swing adsorption process which comprises:

• switching a plurality of adsorption columns packed with an adsorbent successively to an adsorption step, a first pressure equalization step, and evacuation step, a vacuum purge step, a second pressure equalization step and a repressurization step to allow a more strongly adsorbable component gas contained in a gaseous mixture to be adsorbed on the adsorbent and to separate a less strongly adsorbable component gas;
• and
• compressing the thus separated less strongly adsorbable component gas by a product gas compressor to supply it as a product gas;
• wherein procedures of increasing a feed amount of product gas are carried out by inputting a signal for increasing the feed amount of product gas to change each step switching timing in accordance with an operational mode corresponding to an increased feed amount of product gas and then to control an aperture of a flow control valve disposed on a product gas feed passage to a level corresponding to the increased feed amount of product gas.