Fluidized Bed Gas Adsorbers are used to separate gas species from a mixture of gases. They are constituted by a shell containing a fluidized bed of adsorbent particles. The fluidized bed consists of 2 sections - adsorption section and desorption section.
In the adsorption section, sieve trays are used with the raw gas passing up through the perforations (sieves) of the tray, and thus fluidizing the solid adsorbents particles. The fluidized solids flow like a liquid across the tray, into the down comer, and onto the tray below.
From the adsorption section, the solids pass to the desorption section. The solids first flow down through preheating tubes and then through desorption tubes. Steam is used for indirect heating in both sets of tubes and for stripping in the desorption tubes.
Moving beds, rather than fluidized beds on trays, are used in the desorption section because the stripping steam flow rate is insufficient for fluidizing the solids.
At the bottom of the unit, the regenerated solids are picked up by a carrier gas, which flows upward through a gas-lift line in the center of the vessel to the top. At the top, the solids settle out onto the top tray to repeat the adsorption part of the cycle.