Process and power system utilizing potential of ocean thermal energy conversion

• US 8,561,406 B2
• Filed: 08/19/2011
• Issued: 10/22/2013
• Est. Priority Date: 07/21/2011
• Status: Expired due to Fees

• Current Assignee: Kalina Power Limited
• Original Assignee: Kalex, LLC
• Inventors: Kalina, Alexander I.
• Primary Examiner(s): Bomberg, Kenneth
• Assistant Examiner(s): Wan, Deming
• Application Number:
  US13/213,322
• Publication Number:
  US 20130019597A1
• Time in Patent Office: 795 Days
• Field of Search: 60640-657
• US Class Current: 60/641.7
• CPC Class Codes: F03G 7/05 Ocean thermal energy conversion, i.e. OTEC
• CPC Class Codes: Y02E 10/30 Energy from the sea, e.g. using wave energy or salinity gradient

Abstract

Ocean Thermal Energy Conversion (OTEC) systems and methods utilizing the systems are disclosed for producing a useable form of energy utilizing warm surface seawater and cold seawater from depths up to 2 miles below the surface and utilizing a multi-component working fluid. The systems and methods are designed to maximize energy conversion per unit of cold seawater, the limited resource, achieving relative net outputs compared to a Rankine cycle using a single component fluid by at least 20% and even as high as about 55%.

Claims

1. A method for producing electrical and/or mechanical energy from a temperature different between warm surface seawater and cold seawater collected at depths up to 2 miles below the surface of an ocean or sea, where the method comprises:

passing a first rich vapor stream, which may be pressure adjusted in a third throttle control valve if needed, through a turbine unit, where a portion of thermal energy in the first rich vapor stream is converted to a useable form of energy to produce a spent rich solution stream,

combining the spent rich solution stream with a cooled combined lean liquid stream, which may be pressure adjusted in a third throttle control valve if needed, to form an intermediate solution stream, where the intermediate solution stream is leaner than the rich solution stream,

condensing the intermediate solution stream in a first condenser utilizing a cold seawater stream to form a fully condensed, intermediate solution stream to form a warmed cold seawater stream,

pressurizing the fully condensed intermediate solution stream in a first pump to a higher pressure to form a higher pressure, fully condensed, intermediate stream,

preheating the higher pressure, fully condensed, intermediate stream in a second preheater utilizing a combined stream to form a preheated, higher pressure, intermediate stream and the cooled combined stream,

partially vaporizing the preheated, higher pressure, intermediate stream in a second partial vaporizer unit utilizing a second cooled warm seawater substream to form a partially vaporized, higher pressure, intermediate stream,

separating the partially vaporized, higher pressure, intermediate stream in a second separator to form a second rich vapor stream and a second lean liquid stream,

combining the second rich vapor stream with a second substream of a first lean liquid stream to form a rich solution stream,

condensing the rich solution stream in a second condenser utilizing the warmed cold seawater stream to form a fully condensed, rich solution stream,

pressurizing the fully condensed, rich solution stream in a second pump to a higher pressure to form a higher pressure, fully condensed, rich solution stream,

meanwhile, preheating the higher pressure, fully condensed, rich solution stream in a first preheater utilizing a first cooled warm seawater substream to form a preheated, higher pressure, rich solution stream,

partially vaporizing the preheated higher pressure, rich solution stream in a first partial vaporizer unit to form a partially vaporized, rich solution stream and a cooled warm seawater stream,

dividing the cooled warm seawater stream into the first cooled warm seawater substream and the second cooled warm seawater substream,

separating the partially vaporized, rich solution stream in a first separator to form the first rich vapor stream and a first lean liquid stream,

dividing the first lean liquid stream into a first substream of the first lean liquid stream and the second substream of the first lean liquid stream, and combining the first substream of the first lean liquid stream with the second lean liquid stream to form the combined lean liquid stream,

where all of the streams are derived from a multi-component working fluid and where the method is closed with respect to the multi-component working fluid.

2. The method of claim 1, wherein:

the rich vapor streams are richer than the rich solution streams, which is richer than the intermediate streams, which is richer than then lean solution stream, and which is richer than the lean liquid streams,

a temperature differential between the warm seawater and the cold seawater is between about 15°

C. and about 30°

C.,

the useable form of energy is electrical and/or mechanical energy, and a net relative output compared to a Rankine cycle using pure ammonia is increased by at least about 25%.

3. The method of claim 2, wherein a net relative output compared to a Rankine cycle using pure ammonia is increased by at least about 35%.

4. The method of claim 2, wherein a net relative output compared to a Rankine cycle using pure ammonia is increased by at least about 45%.

5. The method of claim 2, wherein a net relative output compared to a Rankine cycle using pure ammonia is increased by at least about 55%.

35. The system of claim 1, wherein the warm seawater supply subsystem collector collects warm seawater from at or with in 10 meters of the surface of the ocean or sea, where the warm seawater has a temperature between about 20°

C. and about 30°

C.

36. The system of claim 1, wherein the cold seawater supply subsystem collector collects cold seawater from a depth between about 0.5 and 1.5 miles below the surface of the ocean or sea having a temperature between about 1°

C. and about 10°

C.

37. The system of claim 1, wherein the multi-component working fluid comprises one or a plurality of lower boiling point components, lower boiling components, and one or a plurality of higher boiling point components, higher boiling components.

38. The system of claim 1, wherein the multi-component working comprises an ammonia-water mixture, a mixture of two or more hydrocarbons, a mixture of two or more freon, a mixture of hydrocarbons and freon.

39. The system of claim 1, wherein the multi-component working fluid comprises a mixture of water and ammonia.

6. A method for producing electrical and/or mechanical energy from a temperature different between warm surface seawater and cold seawater collected at depths up to 2 miles below the surface of an ocean or sea, where the method comprises:

passing a first rich vapor stream, which may be pressure adjusted in a third throttle control valve if needed, through a turbine unit, where a portion of thermal energy in the first rich vapor stream is converted to a useable form of energy to produce a spent rich solution stream,

combining the spent rich solution stream with a cooled combined lean liquid stream, which may be pressure adjusted in a third throttle control valve if needed, to form an intermediate solution stream, where the intermediate solution stream is leaner than the rich solution stream,

condensing the intermediate solution stream in a first condenser utilizing a cold seawater stream to form a fully condensed, intermediate solution stream to form a warmed cold seawater stream,

pressurizing the fully condensed intermediate solution stream in a first pump to a higher pressure to form a higher pressure, fully condensed, intermediate stream,

preheating the higher pressure, fully condensed, intermediate stream in a second preheater utilizing a combined stream to form a preheated, higher pressure, intermediate stream and the cooled combined stream,

combining a first substream of a first lean liquid stream with the preheated, higher pressure, intermediated stream to form a higher pressure, lean stream,

partially vaporizing the higher pressure, lean stream in a second partial vaporizer unit utilizing a second cooled warm seawater substream to form a partially vaporized, higher pressure, lean stream,

separating the partially vaporized, higher pressure, lean stream in a second separator to form a second rich vapor stream and a second lean liquid stream,

combining the second rich vapor stream with a second substream of a first lean liquid stream to form a rich solution stream,

condensing the rich solution stream in a second condenser utilizing the warmed cold seawater stream to form a fully condensed, rich solution stream,

pressurizing the fully condensed, rich solution stream in a second pump to a higher pressure to form a higher pressure, fully condensed, rich solution stream,

meanwhile, preheating the higher pressure, fully condensed, rich solution stream in a first preheater utilizing a first cooled warm seawater substream to form a preheated, higher pressure, rich solution stream,

partially vaporizing the preheated higher pressure, rich solution stream in a first partial vaporizer unit to form a partially vaporized, rich solution stream and a cooled warm seawater stream,

dividing the cooled warm seawater stream into the first cooled warm seawater substream and the second cooled warm seawater substream, separating the partially vaporized, rich solution stream in a first separator to form the first rich vapor stream and a first lean liquid stream,

dividing the first lean liquid stream into a first substream of the first lean liquid stream and the second substream of the first lean liquid stream, and

combining the first substream of the first lean liquid stream with the second lean liquid stream to form the combined lean liquid stream,

where all of the streams are derived from a multi-component working fluid and where the method is closed with respect to the multi-component working fluid.

7. The method of claim 6, wherein:

the rich vapor streams are richer than the rich solution streams, which is richer than the intermediate streams, which is richer than then lean solution stream, and which is richer than the lean liquid streams,

a temperature differential between the warm seawater and the cold seawater is between about 15°

C. and about 30°

C.,

the useable form of energy is electrical and/or mechanical energy, and

a net relative output compared to a Rankine cycle using pure ammonia is increased by at least about 25%.

8. The method of claim 7, wherein a net relative output compared to a Rankine cycle using pure ammonia is increased by at least about 35%.

9. The method of claim 7, wherein a net relative output compared to a Rankine cycle using pure ammonia is increased by at least about 45%.

10. The method of claim 7, wherein a net relative output compared to a Rankine cycle using pure ammonia is increased by at least about 55%.

11. A method for producing electrical and/or mechanical energy from a temperature different between warm surface seawater and cold seawater collected at depths up to 2 miles below the surface of an ocean or sea, where the method comprises:

passing a first rich vapor stream, which may be pressure adjusted in a third throttle control valve if needed, through a turbine unit, where a portion of thermal energy in the first rich vapor stream is converted to a useable form of energy to produce a spent rich solution stream,

combining the spent rich solution stream with a cooled second lean liquid stream, which may be pressure adjusted in a third throttle control valve if needed, to form an intermediate solution stream, where the intermediate solution stream is leaner than the rich solution stream,

condensing the intermediate solution stream in a first condenser utilizing a cold seawater stream to form a fully condensed, intermediate solution stream to form a warmed cold seawater stream,

pressurizing the fully condensed intermediate solution stream in a first pump to a higher pressure to form a higher pressure, fully condensed intermediate stream,

dividing the higher pressure, fully condensed intermediate stream into a first higher pressure, fully condensed intermediate substream and a second higher pressure, fully condensed intermediate substream,

combining the first higher pressure, fully condensed intermediate substream with a second rich vapor stream to form a rich solution stream,

condensing the rich solution stream in a second condenser utilizing the warmed cold seawater stream to form a fully condensed rich solution stream,

pressurizing the fully condensed rich solution stream in a second pump to a higher pressure to form a higher pressure, fully condensed rich solution stream,

preheating the higher pressure, fully condensed rich solution stream in a first preheater utilizing a first cooled warm seawater substream to form a preheated, higher pressure, rich solution stream,

partially vaporizing the preheated higher pressure, rich solution stream in a first partial vaporizer unit to from a partially vaporized, rich solution stream and a cooled warm seawater stream,

dividing the cooled warm seawater stream into the first cooled warm seawater substream and a second cooled warm seawater substream,

separating the partially vaporized, rich solution stream in a first separator to form the first rich vapor stream and a first lean liquid stream,

meanwhile, preheating the second higher pressure, fully condensed, intermediate substream in a second preheater utilizing the second lean liquid stream to form a preheated, second higher pressure, intermediate substream and the cooled second lean liquid stream,

partially vaporizing the preheated, second higher pressure, intermediate substream in a second partial vaporizer unit utilizing the second cooled warm seawater substream to form a partially vaporized, second higher pressure, intermediate substream,

combining the partially vaporized, second higher pressure, intermediate substream with the first lean liquid stream, which may be pressure adjusted by a first throttle control valve if needed, to form a lean solution stream, and

separating the lean solution stream in a second separator to form the second rich vapor stream and the second lean liquid stream,

where all of the streams are derived from a multi-component working fluid and where the method is closed with respect to the multi-component working fluid.

12. The method of claim 11, wherein all of the higher pressures are the same or different, wherein the rich vapor streams are richer than the rich solution streams, which is richer than the intermediate streams, which is richer than then lean solution stream, and which is richer than the lean liquid streams.

13. The method of claim 11, wherein a temperature differential between the warm seawater and the cold seawater is between about 15°

C. and about 30°

C.

14. The method of claim 11, wherein a net relative output compared to a Rankine cycle using pure ammonia is increased by at least about 20%.

15. The method of claim 11, wherein the useable form of energy is electrical and/or mechanical energy.

16. The method of claim 11, wherein a net relative output compared to a Rankine cycle using pure ammonia is increased by at least about 25%.

17. The method of claim 11, wherein a net relative output compared to a Rankine cycle using pure ammonia is increased by at least about 30%.

18. The method of claim 11, wherein a net relative output compared to a Rankine cycle using pure ammonia is increased by at least about 35%.

19. The method of claim 11, wherein a net relative output compared to a Rankine cycle using pure ammonia is increased by at least about 40%.

20. The method of claim 11, wherein a net relative output compared to a Rankine cycle using pure ammonia is increased by at least about 45%.

21. The method of claim 11, wherein a net relative output compared to a Rankine cycle using pure ammonia is increased by at least about 50%.

22. The method of claim 11, wherein a net relative output compared to a Rankine cycle using pure ammonia is increased by at least about 55%.

23. A thermal energy conversion system comprising:

a turbine or energy converting subsystem for converting a portion of thermal energy in a first rich vapor stream into a useable form of energy to from a spent stream,

a condensing subsystem including;

a first condenser for condensing an intermediate solution stream comprising the spent stream and a cooled second lean liquid stream utilizing a higher pressure, cold seawater stream to form a fully condensed, intermediate solution stream,

a first pump for pressurizing the fully condensed intermediate solution stream to a higher pressure to form a higher pressure, fully condensed, intermediate solution stream,

a first dividing valve for dividing the higher pressure, fully condensed, intermediate solution stream into a first higher pressure, fully condensed, intermediate solution substream and a second higher pressure, fully condensed, intermediate solution substream,

a second condenser for condensing a rich solution stream comprising the first fully condensed, higher pressure intermediate solution substream and a second rich vapor stream, and

a second pump for pressurizing the fully condensed, rich solution stream to a higher pressure,

a preheating subsystem including;

a first pre-heater or pre-heating heat exchange unit for preheating the second higher pressure, fully condensed, intermediate solution substream with thermal energy from a second lean liquid stream and

a second pre-heater or pre-heating heat exchange unit for preheating the higher pressure, fully condensed, rich solution stream with thermal energy from a first cooled warm seawater substream,

a partial vaporizing subsystem including;

a first partial vaporizing heat exchange unit for partially vaporizing the preheated, higher pressure, intermediate solution stream with thermal energy from a second cooled warm seawater substream, and

a second partial vaporizing heat exchange unit for partially vaporizing the preheated, higher pressure, rich solution stream with thermal energy from a higher pressure warm seawater stream, and

a separating subsystem including;

a first separator for separating the partially vaporized, higher pressure, rich solution stream into the first rich vapor stream and a first lean liquid stream and a second separator for separating a lean stream comprising the first lean liquid stream and the partially vaporized, higher pressure, intermediate solution stream into the second rich vapor stream and a second lean liquid stream,

where all of the streams are derived from a multi-component working fluid and the system is closed with respect to the multi-component working fluid.

24. The system of claim 23, wherein the turbine or energy converting subsystem comprises a single stage turbine or a multi-stage turbine.

25. The system of claim 23, wherein the condensing subsystem comprises:

a first condenser (HE6) for condensing the intermediate solution stream comprising the spent rich solution stream and the cooled second lean liquid stream utilizing the higher pressure, cold seawater stream,

a first pump (P2) for pressurizing the fully condensed intermediate solution stream to a higher pressure,

a first dividing valve for dividing the higher pressure, fully condensed, intermediate solution stream into the first substream and the second substream,

a second condenser (HE1) for condensing the rich solution stream comprising the first fully condensed, higher pressure intermediate solution substream and the second rich vapor stream, and

a second pump (P1) for pressurizing the fully condensed, rich solution stream to a higher pressure.

26. The system of claim 23, wherein the preheating subsystem comprises:

a first preheater (HE5) for preheating the second fully condensed, higher pressure, intermediate solution substream with thermal energy from the second lean liquid stream and

a second preheater (HE2) for preheating the higher pressure, fully condensed, rich solution stream with thermal energy from the first cooled warm seawater substream.

27. The system of claim 23, wherein the partial vaporizing subsystem comprises:

a first partial vaporizer (HE4) for partially vaporizing the preheated, higher pressure, intermediate solution stream with thermal energy from the second cooled warm seawater substream and

a second partial vaporizer (HE2) for partially vaporizing the preheated, higher pressure, rich solution stream with thermal energy from the higher pressure warm seawater stream.

28. The system of claim 23, wherein the separating subsystem comprising:

a first separator (SP2) for separating the partially vaporized, higher pressure, intermediate solution stream into the first rich vapor stream and the first lean liquid stream and

a second separator (SP1) for separating a lean stream comprising the first lean liquid stream and the partially vaporized, higher pressure, intermediate solution stream into the second rich vapor stream and the second lean liquid stream.

29. The system of claim 23, wherein the warm seawater supply subsystem collector collects warm seawater from at or with in 10 meters of the surface of the ocean or sea, where the warm seawater has a temperature between about 20°

C. and about 30°

C.

30. The system of claim 23, wherein the cold seawater supply subsystem collector collects cold seawater from a depth between about 0.5 and 1.5 miles below the surface of the ocean or sea having a temperature between about 1°

C. and about 10°

C.

31. The system of claim 23, wherein the multi-component working fluid comprises one or a plurality of lower boiling point components, lower boiling components, and one or a plurality of higher boiling point components, higher boiling components.

32. The system of claim 23, wherein the multi-component working comprises an ammonia-water mixture, a mixture of two or more hydrocarbons, a mixture of two or more freon, a mixture of hydrocarbons and freon.

33. The system of claim 23, wherein the multi-component working fluid comprises a mixture of water and ammonia.

34. A system for generating electrical and/or mechanical energy comprising:

a vessel or a floating platform,

a warm seawater supply subsystem comprising a collector, piping and a warm seawater pump (P4), where the warm seawater supply subsystem collects warm seawater from an ocean or a sea and pressurizes it to form a higher pressure warm seawater stream,

a warm seawater discharge subsystem comprising piping including an outlet for discharging spent warm seawater back into the ocean or sea,

a cold seawater supply subsystem comprising a collector, piping and a cold seawater pump (P3), where the cold seawater supply subsystem collects cold seawater from a depth up to two miles below a surface of the ocean or sea,

a cold seawater discharge subsystem comprises piping including an outlet for discharging spent cold seawater back into the ocean or sea, and

a thermal energy conversion subsystem including;

a turbine or energy converting subsystem for converting a portion of thermal energy in a first rich vapor stream into a useable form of energy to from a spent stream, a condensing subsystem including;

a first condenser for condensing an intermediate solution stream comprising the spent stream and a cooled second lean liquid stream utilizing a higher pressure, cold seawater stream to form a fully condensed, intermediate solution stream,

a first pump for pressurizing the fully condensed, intermediate solution stream to a higher pressure to form a higher pressure, fully condensed, intermediate solution stream,

a first dividing valve for dividing the higher pressure, fully condensed, intermediate solution stream into a first higher pressure, fully condensed, intermediate solution substream and a second higher pressure, fully condensed, intermediate solution substream,

a second condenser for condensing a rich solution stream comprising the first fully condensed, higher pressure intermediate solution substream and a second rich vapor stream, and

a second pump for pressurizing the fully condensed, rich solution stream to a higher pressure to form a higher pressure, fully condensed, rich solution stream,

a preheating subsystem including;

a first pre-heater or pre-heating heat exchange unit for preheating the second fully condensed, higher pressure, intermediate solution substream with thermal energy from a second lean liquid stream to form a pre-heated, higher pressure, intermediate solution stream, and

a second pre-heater or pre-heating heat exchange unit for preheating the higher pressure, fully condensed, rich solution stream with thermal energy from a first cooled warm seawater substream,

a partial vaporizing subsystem including;

a first partial vaporizing heat exchange unit for partially vaporizing the preheated, higher pressure, intermediate solution stream with thermal energy from a second cooled warm seawater substream, and

a second partial vaporizing heat exchange unit for partially vaporizing the preheated, higher pressure, rich solution stream with thermal energy from a higher pressure warm seawater stream, and

a separating subsystem including;

a first separator for separating the partially vaporized, higher pressure, rich solution stream into the first rich vapor stream and a first lean liquid stream, and

a second separator for separating a lean stream comprising the first lean liquid stream and the partially vaporized, higher pressure, intermediate solution stream into the second rich vapor stream and a second lean liquid stream,

where all of the streams are derived from a multi-component working fluid and the thermal energy conversion subsystem is closed with respect to the multi-component working fluid.