Process for regenerating adsorbents with supercritical fluids
AssigneeArthur D. Little, Inc.
InventorMichael Modell
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Abstract
An adsorbate is removed from an adsorbent by contacting the adsorbent with a supercritical fluid which is a solvent for the adsorbate. The supercritical fluid containing the dissolved adsorbate is then subjected to a physical treatment which renders the supercritical fluid a nonsolvent for the adsorbate and makes it possible to remove the adsorbate from the supercritical fluid. The supercritical fluid is then subjected to another physical treatment to restore it to a state wherein it is a solvent for the adsorbate so that it may be reused. The process and apparatus are particularly suitable for adsorbent regeneration in the treating of waste water.
Claims24
A process for regenerating an adsorbent by extracting adsorbate therefrom, comprising the steps of
- (a) contacting with a supercritical fluid an adsorbent with adsorbate adsorbed thereon from a solution of said adsorbate, said supercritical fluid being a solvent for said adsorbate thereby to desorb a substantial amount of said adsorbate and to dissolve it in said supercritical fluid, the temperature of said supercritical fluid during said contacting being no greater than about 50.degree. C. above its critical temperature and the pressure being above its critical pressure;
- (b) separating said supercritical fluid with said dissolved adsorbate from said adsorbent, thereby to render said adsorbent capable of adsorbing an additional quantity of said adsorbate;
- (c) subjecting said supercritical fluid containing said adsorbate dissolved therein to physical treatment which renders said fluid a nonsolvent for said adsorbate thereby to form a two-phase system comprising said fluid in a nonsolvent state and said adsorbate;
- (d) separating the resulting two-phase system into nonsolvent state fluid and adsorbate;
- and
- (e) subjecting said nonsolvent state fluid subsequent to said separating step to a physical treatment which converts it to a solvent state supercritical fluid making it a solvent for said adsorbate.
In a process for treating waste water in which at least one organic impurity is adsorbed on an adsorbent from said waste water and said adsorbent is periodically regenerated by removing said impurity therefrom, the improvement comprising regenerating said adsorbent by contacting said adsorbent having said impurity adsorbed thereon with a supercritical fluid which is a solvent for said impurity thereby to desorb a substantial amount of said imputity and to dissolve said impurity in said supercritical fluid and to render said adsorbent capable of again adsorbing said impurity from waste water.
In a process for treating waste water in which at least one organic impurity is adsorbed on activated carbon from said waste water and said carbon is periodically regenerated by removing said impurity therefrom, the improvement comprising regenerating said carbon by
- (a) contacting said carbon with said impurity adsorbed thereon with a supercritical fluid which is a solvent for said impurity thereby to desorb said impurity and dissolve it in said supercritical fluid;
- (b) separating said supercritical fluid with said dissolved impurity from said adsorbent, thereby to remove a substantial amount of said impurity from said carbon and render said carbon capable of adsorbing an additional quantity of said impurity;
- (c) subjecting said supercritical fluid containing said impurity dissolved therein to physical treatment which renders said fluid a nonsolvent for said impurity, thereby to form a two-phase system comprising said fluid in a nonsolvent state and said impurity;
- (d) separating the resulting two-phase system into nonsolvent state fluid and impurity;
- and
- (e) subjecting said nonsolvent state fluid subsequent to said separating step to a physical treatment which converts it to a solvent state supercritical fluid making it a solvent for said impurity.
A process for removing an adsorbate from an adsorbent subsequent to the adsorption of said adsorbate on said adsorbent from a solution of said adsorbate, characterized by contacting said adsorbent with said adsorbate adsorbed thereon with carbon dioxide in a supercritical state thereby to desorb a substantial amount of said adsorbate and to dissolve it in said supercritical carbon dioxide whereby said adsorbent is rendered capable of adsorbing an additional quantity of said adsorbate, said supercritical carbon dioxide during said contacting being at a temperature which is no greater than 50.degree. C. above its critical temperature and at a pressure above its critical pressure.
Dependencies are inferred from the claim text.