Three phase separation process

• US 5,167,838 A
• Filed: 12/30/1991
• Issued: 12/01/1992
• Est. Priority Date: 05/15/1991
• Status: Expired due to Fees

• Current Assignee: Parhelion Incorporated, The Estate of Soma Kurtis
• Original Assignee: Parhelion Incorporated
• Inventors: Wilensky, Joseph
• Primary Examiner(s): Dawson, Robert A.
• Assistant Examiner(s): KIM, SUN U
• Application Number:
  US07/814,564
• Time in Patent Office: 337 Days
• Field of Search: 210/742, 210/768, 210/774, 210/805, 210/808, 62/532, 62/533, 62/48.2, 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-forming material into said solution and then adjusting the temperature, pressure and solute concentration of a resulting single phase composite liquid such that a Joule-Thompson free expansion of said composite liquid will produce a three phase separation of its components.

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) combining the solute/solvent solution with a constant recycle quantity of a liquid product of increased solute concentration obtained from a Joule-Thompson free expansion step of this process and used as a circulating inventory of said concentrated liquid product which is recycled in an amount adjusted to control a solute concentration of a combined solution comprised of a portion of the solute/solvent solution and a portion of the liquid product of increased solute concentration;

(2) dissolving into said combined solution, under a system high pressure state, a controlled amount of a fluid material X which will constitute a vapor phase at a system low temperature and pressure state which exists after the Joule-Thompson free expansion step, in order to produce a fluid material X/solute/solvent solution which constitutes a single phase, composite solution of a given overall composition;

(3) removing any heat of solution and/or heat of condensation of the single phase composite solution and removing sensible heat of said composite solution in a stage-wise manner so as to transit successive temperatures T₂ and T₃ to reach a lower, jumping off temperature T₄ while still essentially at the nominal high pressure;

(4) releasing said nominal high pressure in a Joule-Thompson free expansion to a system low pressure in order to reach a system low temperature T₅ and thereby achieving a solid-liquid-gas equilibrium state (triple point) of the single phase composite solution;

while simultaneously;

(a) evolving substantially all dissolved fluid material X into an evaporated gaseous phase which will have absorbed its heat of vaporization from any remaining solvent and any remaining solute;

(b) distributing any remaining solvent and solute into a solid phase product of pure solvent and a liquid phase product;

(5) separating the solid phase as a product, and

(6) separating the liquid phase into a constant recycle quantity and a remaining "blowdown" quantity composed of total solute of the starting material and unsolidified remaining solvent of the starting material in proportions up to and approaching eutectic (solubility) proportions of the starting material solute and solvent.

2. The process of claim 1 wherein the fluid material X is liquid carbon dioxide.

3. The process of claim 1 wherein the fluid material X is gaseous carbon dioxide.

4. The process of claim 1 wherein the solute/solvent solution starting material is an aqueous solution and the solid phase product is ice.

5. The process of claim 1 wherein the vapor phase product is carbon dioxide gas which is thereafter recompressed into liquid carbon dioxide and reintroduced into the combined solution.

6. The process of claim 1 wherein any portion of any cooling used in going from T₁ (via T₂ and T₃) to T₄ is achieved by heat removal procedures selected from the group consisting of mechanical refrigeration, injection of liquid carbon dioxide and heat exchange with product(s) of the Joule-Thompson free expansion.

7. The process of claim 1 wherein the liquid product of the Joule-Thompson expansion is entirely returned to an inventory of starting material following separation of the solid phase of purified component originally present in excess of eutectic composition.

8. The process of claim 1 wherein the jumping off temperature T₄ is achieved through use of a source of refrigeration which is external to this process.

9. The process of claim 1 wherein a product of the Joule-Thompson free expansion is heat exchanged with an incoming combined solution.

10. The process of claim 1 wherein liquid carbon dioxide is introduced into the single phase, composite solution in order to aid said single phase, composite solution in attaining the jumping off temperature.

11. The process of claim 1 wherein any portion of cooling used in going from T₁ (via T₂ and T₃) to T₄ is achieved by injection of liquid carbon dioxide into the process.

12. The process of claim 1 wherein the distributing of any remaining solvent and solute into a solid phase product of pure solvent and a liquid phase product, does not take place, but rather, because of solute concentration, temperature and/or pressure adjustments to the single phase, composite solution, such distributing of any remaining solvent and solute results in a solid phase product of substantially pure, solid phase, solute which is precipitated from the liquid phase product as a result of the single phase, composite solution undergoing the Joule-Thompson free expansion.

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

(1) combining a portion of solute/solvent solution starting material with a constant recycle quantity of a liquid phase product of a Joule-Thompson free expansion step of this process in order to produce a composite solution of increased solute concentration and in order to aid in production of a single phase liquid composite solution which will have a given overall solute concentration greater than the initial concentration of the solute/solvent solution starting material;

(2) dissolving into said composite solution of increased solute concentration, a controlled amount of a fluid X (which will go into a vapor phase at a system low pressure state which exists after the Joule-Thompson free expansion step), in order to produce a fluid X/solute/solvent composite solution;

(3) placing the fluid X/solute/solvent composite solution under a system nominal high pressure state;

(4) removing heat of mixing and/or heat of condensation (resulting from dissolving fluid X in the solute/solvent solution) and/or sensible heat from the fluid X/solute/solvent composite solution and thereby producing a single phase liquid composite solution having a given overall solute concentration, a nominal high pressure state and a desired jumping off temperature;

(5) releasing the single phase liquid composite solution from the nominal high pressure state to a nominal low pressure state via a Joule-Thompson free expansion in order to achieve a solid-liquid-gas equilibrium state of the single phase liquid composite solution by;

(a) evaporating substantially all dissolved fluid X as a vapor phase product which absorbs its heat of vaporization from the solvent and solute in said single phase liquid composite solution, (b) distributing any solvent and solute remaining after said equilibrium state is reached into a solid phase product of substantially pure solvent and a liquid phase product comprised of any solvent which does not go into the solid phase product and any solute originally contained in the single phase liquid composite solution and thereby producing a liquid phase product having a solute concentration greater than the solute concentration of the solute/solvent solution starting material, and (c) lowering the temperature of the vapor phase product, the liquid phase product and the solid phase product to a temperature which is just above the eutectic temperature of the single phase liquid composite solution;

(6) apportioning the liquid phase product into a constant recycle quantity and a remainder quantity;

(7) recycling the constant recycle quantity of the liquid phase product and combining it with an incoming portion of solute/solvent solution starting material; and

(8) removing the solid phase product as an end product of this process.

14. The process of claim 13 wherein the fluid X is liquid carbon dioxide.

15. The process of claim 13 wherein the fluid X is gaseous carbon dioxide.

16. The process of claim 13 wherein the solute/solvent solution starting material is seawater.

17. The process of claim 13 wherein the solid phase product is a solid form of substantially pure solvent which is washed with pure solvent to remove any liquid phase product on the surface of said solid phase product.

18. The process of claim 13 wherein the solute/solvent solution starting material is a nonaqueous solution containing dissolved minerals.

19. The process of claim 13 wherein the solute/solvent solution starting material is an aqueous industrial waste fluid.

20. The process of claim 13 wherein the jumping off temperature is achieved through use of a source of refrigeration which is external to this process.

21. The process of claim 13 wherein a product of the Joule-Thompson free expansion is heat exchanged against an incoming single phase composite liquid before said product of the Joule-Thompson free expansion is returned to an initial stage of the process.

22. The process of claim 13 wherein liquid carbon dioxide is introduced into the single phase composite liquid in order to aid said composite liquid in attaining the jumping off temperature.

23. The process of claim 13 wherein the vapor phase product is collected and mechanically recompressed into a liquid product for reuse in the process.

24. The process of claim 13 wherein the liquid product of the Joule-Thompson expansion is entirely returned to an inventory of starting material following separation of the solid phase of purified component originally present in excess of eutectic composition.

25. The process of claim 13 wherein the constant recycle quantity of the liquid phase product is an output product of a blowdown procedure performed upon the liquid phase product of the Joule-Thompson free expansion.

26. The process of claim 13 wherein the distributing of any solvent and solute remaining after the equilibrium state is reached into a solid phase product of substantially pure solvent and a liquid phase product having a solute concentration greater than the solute concentration of the solute/solvent solution starting material, does not take place, but rather, because of solute concentration, temperature and/or pressure adjustments to the single phase liquid composite solution, such distributing of any solvent and solute remaining after said equilibrium state is reached results in production of a solid phase product of substantially pure, solid phase, solute precipitated from the liquid phase product as a result of the single phase liquid composite solution undergoing the Joule-Thompson free expansion.

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

(1) dissolving a gas-forming material into the solute/solvent solution in order to produce a dissolved gas/solute/solvent solution;

(2) placing the dissolved gas/solute/solvent solution under a nominal high pressure;

(3) lowering the temperature of the dissolved gas/solute/solvent solution to a jumping off temperature in order to produce a single phase liquid having a solute concentration, temperature and nominal high pressure which are such that a release of the nominal high pressure from said single phase liquid to a nominal low pressure results in evaporation of substatially all of the gas-forming material as a gas which takes its heat of vaporization in an amount such that the temperature of an entire mass of the single phase liquid is lowered to a temperature which approximates the triple point temperature of said single phase liquid;

(4) subjecting the single phase 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 approximating the triple point temperature of the single phase liquid and wherein said three phases of resultant materials comprise a gas phase product containing the gas-forming material originally dissolved in the solute/solvent solution starting material, a liquid phase product having a solute concentration greater than the initial concentration of the solute/solvent solution starting material and a solid phase product of substantially pure solvent;

(5) collecting at least one of the three phases of resultant materials as a product of the process; and

(6) recycling at least one of the three phases of resultant materials back into an earlier stage of the process.

28. The process of claim 27 wherein the gas-forming material is liquid carbon dioxide.

29. The process of claim 27 wherein the gas-forming material is gaseous carbon dioxide.

30. The process of claim 27 wherein the solute/solvent solution starting material is seawater.

31. The process of claim 27 wherein the liquid phase product is a potassium sulfate solution obtained as a by-product of a cement manufacturing process.

32. The process of claim 27 wherein the solute/solvent solution starting material is an aqueous solution containing dissolved minerals and the solid phase product is ice which is thereafter melted and used in the production of a carbonated beverage.

33. The process of claim 27 wherein the solute/solvent solution starting material is a nonaqueous industrial waste fluid.

34. The process of claim 27 wherein the liquid phase product is a brine of nearly eutectic solute concentration from which magnesium carbonate is recovered.

35. The process of claim 27 wherein a quantity of the liquid phase product containing a solute concentration greater than the initial concentration of the solute/solvent solution starting material is recycled to an earlier stage of the process as a constant recycle quantity of said liquid phase product.

36. The process of claim 27 wherein the liquid phase product is subjected to a blowdown procedure and a product of said blowdown procedure is recycled back to an earlier stage of the process as a constant recycle quantity of said product.

37. The process of claim 27 wherein the liquid phase product is separated into a constant recycle quantity and a remaining "blowdown" quantity composed of the starting material total solute and the unsolidified liquid remainder of starting material solvent in proportions up to and approaching eutectic (solubility) composition of the starting material.

38. The process of claim 27 wherein the liquid product of the Joule-Thompson expansion is entirely returned to the inventory of starting material following separation of the solid phase of purified component originally present in excess of eutectic composition.

39. The process of claim 27 wherein liquid carbon dioxide is introduced into the single phase liquid in order to aid said liquid in attaining the jumping off temperature.

40. The process of claim 27 wherein the gas-forming material is carbon dioxide gas which is thereafter mechanically recompressed and reused in the form of liquid carbon dioxide in said process.

41. The process of claim 27 wherein the solid phase product does not have a solute concentration substantially less than the initial concentration of the solute/solvent solution starting material, but rather, because of solute concentration, temperature and/or pressure adjustments to the single phase liquid, is a solid phase product of substantially pure, solid phase, solute which is precipitated from the liquid phase product as a result of said single phase liquid undergoing the Joule-Thompson free expansion.

42. A process for separating a dissolved salt from seawater which together constitute a dissolved salt/seawater solution starting material having an initial dissolved salt concentration and an initial temperature, said process comprising:

(1) placing the dissolved salt/seawater solution under a system high pressure state;

(2) dissolving into said dissolved salt/seawater solution, a controlled amount of a fluid X which will go into a vapor phase at a system low pressure state which exists just after a Joule-Thompson free expansion step of this process;

(3) recycling a quantity of a brine liquid product of said Joule-Thompson free expansion step as a constant recycle quantity which is combined with an incoming portion of seawater in an amount necessary to achieve a desired dissolved salt concentration in a resulting fluid X/dissolved salt/seawater composite solution;

(4) removing heat of mixing and/or heat of condensation present in the resulting fluid X/dissolved salt/seawater composite solution as a result of dissolving fluid X in said dissolved salt/seawater solution;

(5) removing sensible heat from the fluid X/dissolved salt/seawater composite solution in order to achieve a single phase liquid composite solution having a desired jumping off temperature;

(6) releasing, via a Joule-Thompson free expansion, the single phase liquid composite solution having the desired jumping off temperature from a system high pressure state to a system low pressure state and thereby;

(a) evaporating substantially fluid X contained in the single phase liquid composite solution, (b) producing a solid-liquid-vapor equilibrium state in order to produce a vapor phase product comprised of fluid X which absorbs its heat of vaporization from a solid phase product of pure ice and from a brine liquid phase product having a salt concentration greater than the salt concentration of the dissolved salt-seawater solution starting material, (c) producing brine liquid phase product, and (d) distributing a water component of the seawater starting material into the solid phase product of pure ice and into a brine liquid phase product having a dissolved salt concentration near the eutectic concentration of the single phase liquid composite solution;

(7) separating the brine liquid phase product into a constant recycle quantity and a remaining "blowdown" quantity composed of the starting material total solute and a unsolidified liquid remainder of starting material solvent in proportions up to (but not reaching) eutectic (solubility) composition of the single phase liquid composite solution;

(8) washing the solid phase product of pure ice to remove any surface brine; and

(9) melting the solid phase product of pure ice and thereby obtaining pure water as a product of this process.

43. The process of claim 42 wherein the fluid X is liquid carbon dioxide.

44. The process of claim 42 wherein the dissolved salt is magnesium carbonate.

45. The process of claim 42 wherein the liquid product of the Joule-Thompson expansion is entirely returned to the inventory of starting material following separation of the solid phase of purified component originally present in excess of eutectic composition.

46. The process of claim 42 wherein the distributing of the dissolved salt contained in the single phase liquid composite solution to a brine liquid phase product does not take place, but rather, because of solute concentration, temperature and/or pressure adjustments to the single phase liquid composite solution, the distribution results in production of a solid phase product of substantially pure, solid phase, salt precipitated from the brine liquid phase product as a result of the single phase liquid composite solution undergoing the Joule-Thompson free expansion.

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

(1) dissolving liquid carbon dioxide into said solute/aqueous solvent solution in order to;

(a) dissolve the liquid carbon dioxide in the solute/aqueous solvent solution and thereby produce a carbon dioxide/solute/aqueous solvent solution, and (b) produce a carbon dioxide/solute/aqueous solvent solution which takes the form of a single phase composite liquid having a second temperature T₂ which is lower than the initial temperature T₁ of the solute/solvent solution starting material and which temperature T₂ constitutes a jumping off temperature which is such that a release of pressure from the single phase composite liquid from a nominal high pressure to a nominal low pressure results in evolution of substantially all of the carbon dioxide in said single phase composite liquid as carbon dioxide vapor which absorbs its heat of vaporization in a quantity of heat which is such that its loss lowers the temperature of an entire mass of the single phase composite liquid to a temperature T₃ which approximates the triple point temperature of said single phase composite liquid;

(2) placing the single phase composite liquid under a nominal high pressure at temperature T₂ ;

(3) subjecting the single phase composite liquid to a Joule-Thompson free expansion into a vessel having a nominal system low pressure and thereby producing a three-phase separation of the single phase composite liquid and thereby producing three phases of resultant materials which each have a temperature T₃ which approximates the triple point temperature of the single phase composite liquid and wherein said three phases of resultant materials include a carbon dioxide vapor phase product, an aqueous liquid phase product having a solute concentration which approaches the eutectic concentration of the solute in the single phase composite liquid solution, and a solid phase, ice product;

(4) collecting the solid phase, ice product of the three-phase separation;

(5) removing any liquid phase product from the surface of the solid phase, ice product;

(6) melting the solid phase, ice product of the three-phase separation to obtain a substantially pure water; and

(7) recycling a portion of the aqueous liquid phase product as a constant recycle quantity of said liquid phase product and mixing said constant recycle quantity with an incoming portion of the solute/aqueous solvent solution starting material.

48. The process of claim 47 wherein the aqueous liquid phase product of the Joule-Thompson expansion is entirely returned to an inventory of starting material following separation of the solid phase product.

49. A process for separating a solute from a solvent which together constitute a solute/solvent solution starting material having an initial solute concentration said process comprising:

(1) dissolving into said solute/solvent solution, a controlled amount of a fluid X (which will constitute a vapor phase at a system low temperature and pressure state which will exist after a Joule-Thompson free expansion step of this process), in order to produce a fluid X/solute/solvent solution;

(2) placing the fluid X/solute/solvent solution under a nominal high pressure;

(3) lowering the temperature of the fluid X/solute/solvent solution to a jumping off temperature in order to produce a single phase liquid solution having a solute concentration, temperature and nominal high pressure which are such that a release of the nominal high pressure from said single phase liquid solution to a nominal low pressure will result in production of a solid-liquid-gas equilibrium state (triple point) of the single phase liquid solution;

(4) subjecting the single phase liquid solution to a Joule-Thompson free expansion into a vessel having the nominal system low pressure and thereby;

(a) evaporating all of the fluid X as a vapor which takes its heat of vaporization in an amount such that the temperature of an entire mass of the single phase liquid solution is lowered to a temperature which approximates the triple point temperature of the single phase solution,

(b) producing a solid-liquid-gas equilibrium state (triple point) of the single phase liquid solution;

(c) evolving a portion of the solute as a substantially pure, solid phase, solute product,

(d) producing a liquid phase product, and

(e) distributing the solute into a substantially pure, solid phase, solute product and into a liquid phase product comprised of the solvent of the starting material and any remaining solute which is not contained in the pure, solid phase, solute product;

(5) separating the pure, solid phase, solute product from the liquid phase product; and

(6) recycling a constant recycle quantity of a liquid phase product (from which the pure, solid phase, solute product is removed) to a prior stage of the process.

50. The process of claim 49 wherein the fluid X is liquid carbon dioxide.

51. The process of claim 49 wherein the fluid X is gaseous carbon dioxide.

52. The process of claim 49 wherein the solute/solvent solution starting material is seawater.

53. The process of claim 49 wherein the solute/solvent solution starting material is seawater and the pure, solid phase, solute product is magnesium carbonate.

54. The process of claim 49 wherein the solute/solvent solution starting material is seawater and the pure, solid phase, solute product is a mixture of magnesium carbonate and sodium chloride.

55. The process of claim 49 wherein the solute/solvent solution starting material is a nonaqueous, industrial waste liquid.

56. The process of claim 49 wherein the liquid phase product of the Joule-Thompson expansion is entirely returned to an inventory of starting material following separation of the solid phase product.

57. The process of claim 49 wherein the jumping off temperature is achieved through use of a source of refrigeration which is external to this process.

58. The process of claim 49 wherein a product of the Joule-Thompson free expansion is heat exchanged against an incoming single phase composite liquid before said product of the Joule-Thompson free expansion is returned to an initial stage of the process.

59. The process of claim 49 wherein liquid carbon dioxide is introduced into the fluid X/solute/solvent solution in order to aid said solution in attaining the jumping off temperature.

60. The process of claim 49 wherein the vapor phase product is carbon dioxide gas which is mechanically recompressed and reused in the form of liquid carbon dioxide in said process.

61. The process of claim 49 wherein the constant recycle quantity of the liquid phase product is an output product of a blowdown procedure performed upon the liquid phase product of the Joule-Thompson free expansion.

62. The process of claim 49 wherein the liquid phase product is separated into a constant recycle quantity and a remaining "blowdown" quantity composed of the starting material total solute and an unsolidified liquid remainder of starting material solvent in proportions up to and approaching eutectic (solubility) composition of the starting material components.