Adsorption regeneration displacement-purge

While inert and displacement purge regeneration is widely used in liquid phase separations, there are few industrially relevant inert purge systems employed in gas phase separations. It is sufficient to note that an inert purge regeneration can be done and it will generally be most effective at relatively high adsorption temperatures. 

Liquid Adsorption. Adsorption takes place selectively because of (1) polarity differences between adsorbate and unadsorbed liquid, or (2) differences in size and structural characteristics of molecules. In the first category we may mention activated carbon, in the second one the molecular sieves. Liquid adsorption is suitable for both recovery of small amounts from dilute solutions, and for bulk separations. Purification is feasible with very selective adsorbent. Recovery of adsorbate and regeneration of the adsorbent may be performed by (1) Thermal Swing Adsorption, (2) Pressure Swing Adsorption, (3) inert-purge swing, or (4) displacement desorption. 

In gas separation by adsorption, the gaseous feed is put into contact, at adsorption conditions, with an adsorbent that selectively adsorbs some of the components. The feed is then removed from the adsorbent, and the adsorbed components are recovered by desorption at desorption conditions. The adsorbent is usually packed into one or more fixed-bed columns. The preferentially adsorbed species are then removed and the beds are regenerated by either increasing the temperature, as in temperature swing adsorption (TSA), or by purging with a displacement agent, as in displacement purge adsorption... 

The regeneration step in adsorption can be accomplished by pressure-swing (for gaseous species), purge-gas, temperature-swing (TSA processes) or displacement processes (see Section 7.1.1.3). Assuming that the adsorption... 

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