Waste heat recovery in an organic energy converter using an intermediate liquid cycle

• US 6,571,548 B1
• Filed: 12/31/1998
• Issued: 06/03/2003
• Est. Priority Date: 12/31/1998
• Status: Expired due to Term

• Current Assignee: Ormat Technologies Incorporated (Ormat Industries Limited)
• Original Assignee: Ormat Industries Limited
• Inventors: Kaplan, Uri, Amir, Nadav, Bronicki, Lucien Y., Batscha, Danny
• Primary Examiner(s): FREAY, CHARLES GRANT
• Application Number:
  US09/224,279
• Time in Patent Office: 1,615 Days
• Field of Search: 60/390.2, 60/390.4, 60/391.81, 60/391.82
• US Class Current: 60/772
• CPC Class Codes: F01K 23/10 with exhaust fluid of one cycle heating the fluid in another cycle F01K17/025 takes precedence
• CPC Class Codes: Y02E 20/14 Combined heat and power generation [CHP]
• CPC Class Codes: Y02E 20/16 Combined cycle power plant [CCPP], or combined cycle gas turbine [CCGT]

Abstract

A heat recovery method and system that extracts heat from the exhaust of a gas turbine unit in a waste heat, heat exchanger and transfers the heat to an intermediate fluid, which can be pressurized water. The intermediate fluid in-turn transfers the heat to an organic working fluid resulting in the vaporization thereof. The vaporized organic working fluid drives a series of turbines which in turn drive a generator that generates electricity.

Claims

1. A method of generating power using exhaust gases from a gas turbine unit comprising:

heating an intermediate fluid with said exhaust gases;

vaporizing an organic liquid working fluid with said heated intermediate fluid in a vaporizer to form a vaporized working fluid and a heat depleted intermediate fluid;

expanding said vaporized working fluid in an organic vapor turbine for generating power and producing an expanded vaporized working fluid;

condensing said expanded vaporized working fluid to produce a condensate;

transmitting the condensate back to said vaporizer;

and preheating said condensate with said heat depleted intermediate fluid before said vaporizing step.

2. A method as claimed in claim 1, wherein said intermediate fluid is pressurized water flowing in a closed, pressurized liquid water flow system.

3. A method as claimed in claim 2 and further including controlling the ratio of the amount of said heat depleted intermediate fluid preheating said condensate to the rest of said intermediate fluid.

4. A method as claimed in claim 2 and further including a further preheating step of said condensate by heating said condensate with said expanded vaporized working fluid before said condensate is preheated by said heat depleted intermediate fluid.

5. A method as claimed in claim 2 wherein said organic fluid is pentane.

6. A method of recovering energy from waste heat that is produced by a heat source comprising:

providing a heated intermediate fluid heated by the waste heat;

providing a gaseous working organic fluid vapor that has been vaporized from a liquid by said heated intermediate fluid in a vaporizer in which a heat depleted intermediate fluid is produced;

generating electrical power from said gaseous working organic fluid valpor with an electrical generator driven by an organic vapor turbine that is in turn driven by said gaseous working organic fluid vapor, which produces an expanded working fluid vapor;

producing a condensate in a condenser from said working organic fluid valpor after the use thereof in the organic vapor turbine; and

providing said condensate to said vaporizer;

and producing a preheated condensate before said condensate is provided to said vaporizer with said heat depleted intermediate fluid after the intermediate fluid has vaporized the organic fluid.

7. A method of recovering energy from waste heat as claimed in claim 6 wherein said condensate is preheated with said expanded vaporized working fluid.

8. A method for recovering energy from waste heat as claimed in claim 6 wherein said working fluid is pentane.

9. A method of recovering energy from waste heat as claimed in claim 6 wherein said intermediate fluid is pressurized water flowing in a closed, pressurized liquid water flow system.

10. A method for recovering energy from waste heat as claimed in claim 6, and further including producing a preheated condensate with said expanded working fluid vapor before said condensate is preheated by said heat depleted intermediate fluid.

11. A method according to claim 9 further including controlling the ratio of the amount of said heat depleted intermediate fluid preheating said condensate to the rest of said intermediate fluid.

12. A method according to claim 9 including pressurizing said pressurized water flowing in a closed, pressurized liquid water flow system to a pressure so that said water will not freeze at temperatures in cold climates on earth.

13. A method according to claim 9 including providing a pre-heater in which said condensate is heated with heat depleted intermediate fluid before entering said vaporizer.

14. A method according to claim 6 including pressurizing said intermediate fluid.

15. A method according to claim 12 including storing pressurized intermediate fluid and pumping said intermediate fluid from a storage tank into the cycle of said intermediate fluid.

16. A method for recovering energy from waste heat as claimed in claim 6 wherein said intermediate fluid is pressurized water.

33. A method according to claim 11 wherein the step of generating electrical power from said gaseous organic fluid vapor with an electrical generator driven by an organic vapor turbine is carried out by expanding said gaseous organic fluid vapor at high pressure and thereafter at low pressure in separate modules.

34. A method according to claim 33 wherein the step of generating electrical power from said gaseous organic fluid vapor with an electrical generator is carried out by constructing and arranging said electrical generator to be driven by the high pressure and the low pressure modules.

35. A method according to claim 34 wherein the step of generating electrical power from said gaseous organic fluid vapor with an electrical generator is carried out by constructing and arranging said electrical generator to be interposed and driven by the high pressure and the low pressure modules.

17. A heat recovery system that uses the heat produced by a power generating source, the heat recovery system comprising:

a supply of heat from a power generating source;

a heat recovery heat exchanger which receives said supply of heat and in which an intermediate fluid is heated by the supply of heat;

an intermediate fluid system containing an intermediate fluid and including

an intermediate fluid pump having an input and a discharge and lines connected to said pump input and discharge and to said heat exchanger, said lines containing and delivering said intermediate fluid;

a vaporizer in which a vaporized organic working fluid is produced from a liquid organic working fluid with heat contained in said intermediate fluid, said lines connecting said heat recovery heat exchanger to said vaporizer and heat depleted intermediate fluid being discharged from said vaporizer.

an organic vapor turbine that is driven by the vaporized organic working fluid and from which an expanded vaporized organic working fluid exits;

a condenser in which said expanded vaporized organic working fluid condenses into a condensate;

a main condensate pump that is supplied with condensate from said condenser and in turn supplies the condensate to said vaporizer;

and a preheater in which said condensate is heated with heat depleted intermediate fluid before entering said vaporizer.

18. A heat recovery system as claimed in claim 17 wherein said organic working fluid is pentane.

19. A heat recovery system as claimed in claim 18 wherein said intermediate fluid is pressurized water flowing in a closed, pressurized liquid water flow system having a pressure so that said water will not freeze in temperatures found in cold climates on earth.

20. A heat recovery system as claimed in claim 17, wherein said heat recovery heat exchange comprises a lower first set of coils having an input and an output, an upper second set of coils having an input and an output, and a cross-connect line connecting said first set of coils output to said input of said second set of coils;

and

wherein said output of said intermediate fluid pump is connected to said cross-connect conduit; and

wherein said intermediate fluid pump discharges through a valve to said cross-connect line.

21. A heat recovery system according to claim 17 wherein said intermediate fluid is pressurized water flowing in a closed, pressurized liquid water flow system.

22. A heat recovery system as claimed in claim 21, wherein said intermediate fluid system further includes a pressurizer connected to a first line located between the discharge of said intermediate fluid pump and said heat exchanger.

23. A heat recovery system as claimed in claim 21 wherein said intermediate fluid system further includes a storage tank having an inlet and an outlet, and a makeup liquid pump connected with lines between said storage tank and said lines connecting said heat recovery heat exchanger to said vaporizer.

24. A heat recovery system as claimed in claim 22 and further including a storage tank having an inlet and an outlet, and a pump connected with lines between said storage tank and said first line located between the discharge of said intermediate fluid pump and said heat exchanger;

and wherein said pressurizer includes a level controller connection that is connected to said storage tank.

25. A heat recovery system as claimed in claim 21 wherein said preheater has a primary side containing a heat providing fluid and a secondary side containing a heat receiving fluid, said preheater receiving said heat depleted intermediate fluid from the vaporizer on the primary side, and receiving said condensate via said condensate pump on the secondary side thereof and providing a further heat depleted intermediate fluid to said heat recovery heat exchanger.

26. The heat recovery system according to claim 17 further including a recuperator for preheating condensate with said expanded vaporized organic working fluid before said condensate is supplied to said preheater for preheating the condensate with heat depleted intermediate fluid.

27. The heat recovery system according to claim 21 wherein said organic vapor turbine further comprises a high pressure turbine module and a low pressure turbine module.

28. The heat recovery system according claim 26 further including an electric generator.

29. The heat recovery system according to claim 28 wherein the electric generator is driven by both the high pressure turbine module and the low pressure turbine module.

30. The heat recovery system according to claim 29 wherein the electric generator is interposed between the high pressure turbine module and the low pressure turbine module.

31. A heat recovery system according to claim 17 further including means for controlling the ratio of the amount of said heat depleted intermediate fluid preheating said condensate to the rest of said intermediate fluid.

32. A heat recovery system according to claim 31 wherein said means for controlling the ratio of the amount of said heat depleted intermediate fluid preheating said condensate to the rest of said intermediate fluid comprises a valve.