Three phase separation process

• US 5,084,187 A
• Filed: 05/15/1991
• Issued: 01/28/1992
• Est. Priority Date: 05/15/1991
• Status: Expired due to Fees

• Current Assignee: Parhelion Incorporated, Soma Kurtis
• Original Assignee: Soma Kurtis
• Inventors: Wilensky, Joseph
• Primary Examiner(s): KIM, SUN U
• Application Number:
  US07/701,452
• Time in Patent Office: 258 Days
• Field of Search: 210/742, 210/774, 210/768, 210/805, 210/808, 62/532, 159/DIG. 5
• US Class Current: 210/768
• CPC Class Codes: B01D 9/04 concentrating solutions by removing frozen solvent therefrom
• CPC Class Codes: C02F 1/22 by freezing
• CPC Class Codes: C02F 2103/08 Seawater, e.g. for desalination
• CPC Class Codes: Y02A 20/124 Water desalination

Abstract

A solute can be separated from a solute/solvent solution by dissolving a gas into the solution to produce a single phase composite liquid, lowering the temperature of the composite liquid to a certain temperature and then performing a Joule-Thompson free expansion on the composite liquid.

Claims

1. A process for separating a solute from a solvent which together constitute a solute/solvent solution starting material having an initial solute concentration and an initial temperature T₁, said process comprising:

(1) introducing a partially soluble gas into the solute/solvent solution in order to dissolve the partially soluble gas in the solute/solvent solution and thereby releasing the heat of condensation of the gas into said solution and in order to produce a dissolved gas/solute/solvent solution which takes the form of a single phase composite liquid material having a second temperature T₂ which is greater than the initial temperature T₁ of the solute/solvent solution starting material;

(2) placing the single phase composite liquid under a nominal high pressure by use of a pump means;

(3) introducing the single phase composite liquid having the second temperature T₂ into a first heat exchange means having a source of cold in order to remove a quantity of heat from the single phase composite liquid which approximates the heat of condensation of the dissolved gas and whose loss brings the single phase composite liquid to a third temperature T₃ which approximates the initial temperature T₁ of the solute/solvent solution starting material;

(4) introducing the single phase composite liquid having the third temperature T₃ into a second heat exchange means employing a source of cold other than the source of cold employed by the first heat exchange means in order to lower the temperature of the single phase composite liquid from the third temperature T₃ to a fourth temperature T₄ which is such that a release of pressure on the single phase composite liquid from the nominal high pressure to a nominal low pressure results in evolution of substantially all of the dissolved gas which, upon vaporization, absorbs heat of condensation in a quantity which is required to lower the temperature of an entire mass of the single phase composite liquid to a temperature T₅ which approximates the triple point temperature of said single phase composite liquid;

(5) subjecting the single phase composite liquid to a Joule-Thompson free expansion into a vessel having a nominal system low pressure and thereby obtaining three phases of resultant materials which each have a temperature T₅ which approximates the triple point temperature of the single phase composite liquid and wherein said three phases of resultant materials will include a vapor phase product containing the gas dissolved in the single phase composite liquid material, a liquid phase product containing a solute concentration different from the solute concentration of the solute/solvent solution starting material and a solid phase product containing a solute concentration different from that of the solute/solvent solution starting material; and

(6) collecting at least one of the three phases of resultant materials as a product of the process.

2. The process of claim 1 wherein the solute/ solvent solution starting material is sea water.

3. The process of claim 1 wherein the solute/solvent solution starting material is an industrial waste liquid.

4. The process of claim 1 wherein the partially soluble gas is carbon dioxide.

5. The process of claim 1 wherein the introduction of the partially soluble gas into the solute/ solvent solution is accomplished by means of a jet eductor wherein the solute/solvent solution is employed as a motive fluid and the partially soluble gas is educted into said solute/solvent solution.

6. The process of claim 1 wherein the solute/ solvent solution starting material is augmented by a portion of the liquid phase material produced by the Joule-Thompson free expansion of the single phase composite liquid material in order to produce a liquid phase product which approximates the eutectic composition of the single phase composite liquid.

7. The process of claim 1 wherein the single phase composite liquid is formed, in part, by adjusting an operating temperature of the jet eductor.

9. The process of claim 1 wherein the solute/ solvent solution starting material is raised to a temperature which is greater than the temperature T₁ of an incoming solute/solvent solution starting material by pumping said incoming solute/solvent solution starting material and thereupon employing said starting material as a motive fluid for a jet eductor.

10. The process of claim 1 wherein the vapor phase product produced by the Joule-Thompson free expansion is heat exchanged against the single phase composite liquid before it is returned to an initial stage of the process and redissolved into a new, incoming portion of solute/solvent solution starting material.

11. The process of claim 1 wherein the vapor phase product produced by the Joule-Thompson free expansion is directly returned to an eduction port of a jet eductor and educted into a solute/solvent solution which is used as a motive fluid in said jet eductor.

12. The process of claim 1 wherein the lowering of the temperature of the single phase composite liquid from the third temperature T₃ to a fourth temperature T₄ is accomplished by heat exchange with a resultant material from the Joule-Thompson free expansion selected from the group of resultant materials consisting of its vapor phase product, its liquid phase product or its solid phase product.

13. The process of claim 1 wherein the solute/ solvent solution starting material is mixed with a liquid product of the Joule-Thompson free expansion, in order to form a solute concentration in excess of that of an eutectic composition, at its triple point, so that solute can be obtained from the Joule-Thompson free expansion of the single phase composite liquid.

14. The process of claim 1 wherein the solute/ solvent solution starting material is sea water mixed with a brine product of the Joule-Thompson free expansion in order to make a feed liquid which contains a sodium chloride concentration greater than that of sea water in order that the ice obtained from the Joule-Thompson free expansion of the single phase composite liquid material is obtained as a substantially pure ice product.

15. The process of claim 1 wherein a resultant material from the Joule-Thompson free expansion selected from the group of resultant materials consisting of its vapor phase material, its liquid phase material or its solid phase material are employed for refrigeration purposes outside of the process for separating the solute from the solvent.

16. The process of claim 1 wherein a resultant material from the Joule-Thompson free expansion selected from the group of resultant materials consisting of its vapor phase material, its liquid phase material or its solid phase material are employed to control operating conditions of a jet eductor in which the gas is dissolved into the solute/ solvent solution starting material in order to form the single phase composite liquid.

8. The process of claim wherein the temperature T₅ which approximates a triple point temperature T_e of the single phase composite liquid lies just slightly above said triple point temperature T_e.

17. A process for obtaining potable water from a sea water solution staring material comprised of a salt component dissolved in a water component and having an initial salt component concentration and an initial temperature T₁, said process comprising:

(1) pumping the sea water solution into an eductor;

(2) educting carbon dioxide gas into the sea water solution by use of a jet eductor wherein the sea water solution is pumped into the jet eductor as a motive fluid and the carbon dioxide gas is educted into the jet eductor and, hence, dissolved into the sea water solution and thereby releasing the heat of condensation of the carbon dioxide gas into said sea water solution and producing a dissolved carbon dioxide gas/salt component/water component solution in the form of a single phase composite liquid having a nominal high pressure and a second temperature T₂ which is greater than the initial temperature T₁ of the sea water solution starting material and wherein at least a portion of the carbon dioxide educted into the sea water solution is obtained from a subsequent Joule-Thompson free expansion step of the process;

(3) introducing the single phase composite liquid having the second temperature T₂ into a first heat exchange means which uses a body of sea water as a source of cold in order to remove a quantity of heat from the single phase composite liquid which approximates the heat of condensation of the carbon dioxide in order to bring the single phase composite liquid to a third temperature T₃ which approximates the initial temperature T₁ of the sea water starting material and wherein the operating temperature conditions of the eductor are adjusted to promote production of a single phase composite liquid which is comprised of dissolved carbon dioxide, a salt component and a water component by use of temperature adjusting means which include use of the temperature contained in a carbon dioxide vapor produced by the Joule-Thompson free expansion of the single phase composite liquid;

(4) introducing the single phase composite liquid having a third temperature T₃ into a second heat exchange means which is at least partially cooled by heat exchange with a resultant material from the Joule-Thompson free expansion which has a temperature T₅ which approximates a triple point temperature T_e of the single phase composite liquid and which resultant material is selected from the group of resultant materials consisting of the Joule-Thompson free expansion'"'"'s vapor phase product, its liquid phase product or its solid phase product in order to lower the temperature of the single phase composite liquid from the third temperature T₃ to a fourth temperature T₄ which is such that a release of pressure on the single phase composite liquid from the nominal high pressure to a nominal low pressure results in the evolution of substantially all of the dissolved carbon dioxide which, upon vaporization, absorbs heat of condensation in a quantity which is required to lower the temperature of an entire mass of the single phase composite liquid to a temperature which approximates the triple point temperature T₅ of said single phase composite liquid;

(5) subjecting the single phase composite liquid to a Joule-Thompson free expansion into a vessel under a nominal system low pressure and thereby obtaining three phases of resultant product materials each have a temperature T₅ which approximates the single phase liquid'"'"'s triple point temperature and which will include a vapor phase product containing the carbon dioxide gas originally dissolved in the single phase composite liquid, a brine-like liquid phase product containing a salt component concentration greater than the salt component concentration of the sea water starting material and an ice-like, solid phase product containing a salt component concentration which is substantially less than the salt component concentration of the sea water starting material and such that when the ice-like, solid phase product is melted, the resulting water is potable;

(6) recycling the carbon dioxide vapor produced by the Joule-Thompson free expansion of the single phase composite liquid material back for re-eduction into the jet eductor;

(7) separating the ice-like, solid phase product material from its association with the brine-like liquid phase product and from the carbon dioxide, vapor phase product of the Joule-Thompson expansion; and

(8) melting the ice-like, solid phase product material to obtain potable water.

18. The process of claim 17 wherein the brine-like liquid phase product is mixed with incoming sea water to raise the solute concentration of the sea water such that a composition of the single phase composite liquid entering the Joule-Thompson free expansion will result in a liquid product which approximates the eutectic composition of the single phase composite liquid.

19. The process of claim 17 wherein the brine-like liquid phase product having a temperature T₅ is used as a heat exchange fluid in a heat exchange system which serves to lower the temperature of the single phase composite liquid material to a brink temperature T₄.

20. The process of claim 17 wherein the ice-like, solid phase product material is melted by heat exchange against the single phase composite liquid after said single phase composite liquid leaves the first heat exchange means, but before it enters the second heat exchange means.

21. The process of claim 17 wherein a portion of the water formed by melting the ice-like solid phase product is used to wash away surface brine from ice subsequently produced by the Joule-Thompson free expansion.

22. The process of claim 17 wherein the solute/solvent solution starting material is mixed with a product of the Joule-Thompson free expansion, in order to form a solute concentration in excess of that of an eutectic composition, at its triple point, so that solute is obtained from the Joule-Thompson free expansion of the single phase composite liquid material.