Rankine cycle power plant utilizing organic working fluid

• US 5,531,073 A
• Filed: 06/02/1995
• Issued: 07/02/1996
• Est. Priority Date: 07/01/1989
• Status: Expired due to Term

• Current Assignee: Ormat Technologies Incorporated (Ormat Industries Limited)
• Original Assignee: Ormat Turbines Ltd.
• Inventors: Bronicki, Lucien Y., Elovic, Asher
• Primary Examiner(s): Look, Edward K.
• Assistant Examiner(s): NGUYEN, HOANG M
• Application Number:
  US08/460,728
• Time in Patent Office: 396 Days
• Field of Search: 60/641.2, 60/641.3, 60/641.5, 60/653, 60/676
• US Class Current: 60/641.2
• CPC Class Codes: F01D 15/10 Adaptations for driving, or combinations with, electric generators
• CPC Class Codes: F01K 23/04 condensation heat from one cycle heating the fluid in another cycle
• CPC Class Codes: F01K 25/08 using special vapours
• CPC Class Codes: F03G 7/04 using pressure differences or thermal differences occurring in nature F03G7/06 takes precedence

Abstract

A Rankine cycle power plant includes a pair of multistage turbine modules each of which has an input for receiving vaporized working fluid and an output shaft, and each of which is responsive to vaporized working fluid applied to its input for expanding the working fluid and producing work at the output shaft and heat depleted working fluid that is superheated. An electrical generator is located between the modules and directly coupled to their output shafts. Superheated, heat depleted working fluid from one of the modules is supplied to the input of the other of the modules.

Claims

1. Apparatus for producing power comprising:

a) a pair of multi-staged turbine modules each of which has an input for receiving vaporized working fluid and an output shaft, and each of which is responsive to vaporized working fluid applied to its input for expending the working fluid and producing work at the output shaft and heat depleted working fluid that is superheated;

b) an electric generator located between said modules and directly coupled to their output shafts; and

c) means for supplying superheated, heat depleted working fluid from one of the modules to the input of the other of the modules.

2. Apparatus according to claim 1 including:

a) a vaporizer for supplying vaporized working fluid to said one of the modules, and a preheater for supplying heated working fluid to said vaporizer;

b) a mixer interposed between said modules through which superheated, heat depleted working fluid from said one of the modules is transferred to the input of the other of the modules; and

c) means for supplying liquid working fluid to said mixer for desuperheating the working fluid supplied to the input of the other of the modules.

3. Apparatus according to claim 2 wherein the liquid working fluid supplied to said mixer is heated working fluid produced by said preheater.

4. Apparatus according to claim 3 wherein the liquid working fluid supplied to said mixer is sprayed into the superheated, heat depleted working fluid in the mixer.

5. Apparatus according to claim 4 wherein said working fluid is an organic working fluid.

15. Apparatus according to claim 1 wherein said working fluid is an organic fluid.

16. Apparatus according to claim 1 wherein said working fluid is pentane.

55. Apparatus according to claim 1 wherein the electric generator positioned between the modules permits the generator to be directly driven by the output shafts of the modules at the same rotational speed as the modules at a relatively low speed.

56. Apparatus according to claim 55 wherein the relatively low speed is 1800 RPM.

70. Apparatus for producing power according to claim 1 including means for supplying geothermal fluid to the vaporizers of said systems.

71. Apparatus according to claim 70 wherein the electric generator positioned between the modules permits the generator to be directly driven by the output shafts of the modules at the same rotational speed as the modules at a relatively low speed.

72. Apparatus according to claim 71 wherein the relatively low speed is 1800 RPM.

6. A method for producing power from a pair of multi-staged turbine modules, each of which has an input for receiving vaporized working fluid, and an output shaft, and each of which is responsive to vaporized working fluid applied to its input for expanding the working fluid and producing work at the output shaft and heat depleted working fluid that is superheated, said method comprising the steps of:

a) positioning an electric generator between the modules such that the generator is directly driven by the output shafts of the modules at the same rotational speed as the modules; and

b) supplying superheated, heat depleted working fluid from one of the modules to the input of the other of the modules.

7. A method according to claim 6 including vaporizing the working fluid and supplying it to said one of the modules, mixing superheated, heat depleted working fluid from said one of the modules with liquid working fluid for desuperheating the vaporized working fluid before it is supplied to the input of said other of the modules.

8. A method according to claim 7 wherein the liquid fluid mixed with the superheated, heat depleted working fluid is preheated liquid working fluid.

9. Method according to claim 8 wherein mixing of the liquid working fluid with the superheated, heat depleted working fluid is achieved by spraying the liquid working fluid into the superheated, heat depleted working fluid.

10. Method according to claim 9 wherein said working fluid is an organic fluid.

17. A method according to claim 6 wherein said working fluid is an organic fluid.

18. A method according to claim 6 wherein said working fluid is pentane.

51. A method according to claim 6 wherein the step of positioning an electric generator between the modules permits the generator to be directly driven by the output shafts of the modules at the same rotational speed as the modules such that the modules rotate at a relatively low speed.

52. A method according to claim 51 wherein the relatively low speed is 1800 RPM.

11. A Rankine cycle power plant comprising:

a) a preheater for preheating liquid working fluid;

b) a vaporizer for vaporizing preheated liquid working fluid produced by said preheater;

c) a first turbine module having an input for receiving vaporized working fluid produced by said vaporizer and having an output shaft, said first module being responsive to vaporized working fluid for expanding the working fluid to produce work at the output shaft and heat depleted working fluid that is superheated;

d) a second turbine module having an input for receiving heat depleted working fluid from the first module and having an output shaft, said second module being responsive to vaporized working fluid for expanding the working fluid to produce work at the output shaft and heat depleted working fluid that is superheated;

e) an electric generator located between said modules and coupled to their output shafts;

f) means for supplying superheated, heat depleted working fluid from the first module to the input of the second module; and

g) a condenser for condensing heat depleted working fluid produced by said second module, and means for supplying condensate produced by the condenser to the preheater.

12. A power plant according to claim 11 including a mixer interposed between said first and second modules through which superheated, heat depleted working fluid from said first module is transferred to the input of the second module, and means for supplying liquid working fluid to said mixer for desuperheating the working fluid supplied to the input of said second module.

13. A power plant according to claim 12 wherein the liquid working fluid supplied to said mixer is working fluid produced by said preheater.

14. A power plant according to claim 12 wherein the liquid working fluid supplied to said mixer is sprayed into the superheated, heat depleted working fluid in the mixer.

57. A power plant according to claim 11 wherein the electric generator positioned between the modules is directly coupled to the output shafts of the modules.

58. A power plant according to claim 57 wherein the electric generator positioned between the modules permits the generator to be directly driven by the output shafts of the modules at the same rotational speed as the modules at a relatively low speed.

59. Apparatus according to claim 58 wherein the relatively low speed is 1800 RPM.

66. A power plant according to claim 11 wherein the electric generator positioned between the modules permits the generator to be directly driven by the output shafts of the modules at the same rotational speed as the modules at a relatively low speed.

67. A power plant according to claim 66 wherein the relatively low speed is 1800 RPM.

73. A power plant according to claim 11 including means for supplying geothermal fluid to the vaporizers of said systems.

74. A power plant according to claim 73 wherein the electric generator positioned between the modules is directly coupled to the output shafts of the modules.

75. A power plant according to claim 74 wherein the electric generator positioned between the modules permits the generator to be directly driven by the output shafts of the modules at the same rotational speed as the modules at a relatively low speed.

76. Apparatus according to claim 75 wherein the relatively low speed is 1800 RPM.

19. Apparatus for producing power comprising:

a) a plurality of systems each having;

(1) a pair of multi-stage turbines, each of which has an input for receiving vaporized working fluid and an output shaft, and each of which is responsive to vaporized working fluid applied to its input for expanding the working fluid and producing work at the output shaft, and heat depleted working fluid that is superheated;

(2) an electric generator located between said modules and directly coupled to their respective output shafts;

(3) means for supplying superheated, heat depleted working fluid from one of the modules to the input of the other of the module;

(4) a vaporizer for supplying vaporized working fluid to said one of the modules; and

(5) a preheater for supplying heated working fluid to said vaporizer;

b) means for serially supplying medium or low temperature fluid from a low grade heat source to the vaporizers to produce heat depleted source fluid; and

c) means for supplying heat depleted source fluid to the preheaters in parallel.

20. Apparatus according to claim 19 wherein said working fluid is an organic fluid.

21. Apparatus according to claim 19 wherein said working fluid is pentane.

45. Apparatus for producing power according to claim 19 wherein said medium or low temperature fluid from said low grade heat source is geothermal fluid.

46. Apparatus for producing power according to claim 45 wherein said geothermal fluid is geothermal water.

60. Apparatus according to claim 19 wherein the electric generator positioned between the modules permits the generator to be directly driven by the output shafts of the modules at the same rotational speed as the modules at a relatively low speed.

61. Apparatus according to claim 60 wherein the relatively low speed is 1800 RPM.

22. A method for producing power using a plurality of systems each having:

(1) a pair of multi-stage turbines, each of which has an input for receiving vaporized working fluid and an output shaft, and each of which is responsive to vaporized working fluid applied to its input for expanding the working fluid and producing work at the output shaft, and heat depleted working fluid that is superheated;

(2) an electric generator located between said modules and directly coupled to their respective output shafts;

(3) means for supplying superheated, heat depleted working fluid from one of the modules to the input of the other of the module;

(4) a vaporizer for supplying vaporized working fluid to said one of the modules; and

(5) a preheater for supplying heated working fluid to said vaporizer;

said method comprising the steps of;

a) serially supplying medium or low temperature fluid from a low grade heat source to the vaporizers to produce heat depleted source fluid; and

b) supplying said depleted source fluid to the preheaters in parallel.

23. A method according to claim 22 wherein said step of serially supplying medium or low temperature fluid is carried out using hot geothermal water.

24. A method according to claim 22 wherein the working fluid is an organic fluid.

25. A method according to claim 22 wherein the working fluid is pentane.

50. A method according to claim 22 wherein the step of serially supplying medium or low temperature fluid from said low grade heat source to the vaporizers is carried out by supplying geothermal fluid to the vaporizers.

26. Apparatus for producing power from a plurality of systems, comprising:

a) a pair of multi-stage turbines, each of which has an input for receiving vaporized working fluid and an output shaft, and each of which is responsive to vaporized working fluid applied to its input for expanding the working fluid and producing work at the output shaft, and heat depleted working fluid that is superheated;

b) an electric generator located between said modules and directly coupled to their respective output shafts;

c) means for supplying superheated, heat depleted working fluid from one of the modules to the input of the other of the module;

d) a vaporizer for supplying vaporized working fluid to said one of the modules; and

(5) a preheater for supplying heated working fluid to said vaporizer.

27. Apparatus according to claim 26 including means for supplying medium or low temperature source fluid from a low grade heat source to the vaporizers of said systems in series to produce heat depleted source fluid, and means for supplying heat depleted source fluid to the preheaters of the systems in parallel.

28. An apparatus according to claim 26 wherein the working fluid is an organic fluid.

29. An apparatus according to claim 26 wherein the working fluid is pentane.

62. Apparatus according to claim 26 wherein the electric generator positioned between the modules permits the generator to be directly driven by the output shafts of the modules at the same rotational speed as the modules at a relatively low speed.

63. Appartus according to claim 62 wherein the relatively low speed is 1800 RPM.

77. Apparatus for producing power according to claim 26 including means for supplying geothermal fluid to the vaporizers of said systems.

78. Apparatus according to claim 77 wherein the electric generator positioned between the modules permits the generator to be directly driven by the output shafts of the modules at the same rotational speed as the modules at a relatively low speed.

79. Apparatus according to claim 78 wherein the relatively low speed is 1800 RPM.

30. A method for producing power using a plurality of systems each having:

(1) a pair of multi-stage turbines, each of which has an input for receiving vaporized working fluid and an output shaft, and each of which is responsive to vaporized working fluid applied to its input for expanding the working fluid and producing work at the output shaft, and heat depleted working fluid that is superheated;

(2) an electric generator located between said modules and directly coupled to their respective output shafts;

(3) a vaporizer for supplying vaporized working fluid to said one of the modules; and

(4) a preheater for supplying heated working fluid to said vaporizer;

said method comprising the steps of;

a) supplying superheated, heat depleted working fluid from one of the modules to the input of the other of the module.

31. A method according to claim 30 including the step of supplying medium or low temperature source fluid from a low grade heat source to the vaporizers of said systems in series to produce heat depleted source fluid, and means for supplying heat depleted source fluid to the preheaters of the systems in parallel.

32. A method according to claim 30 wherein said step of serially supplying medium or low temperature fluid is carried out using hot geothermal water.

33. A method according to claim 30 wherein the working fluid is an organic fluid.

34. A method according to claim 30 wherein the working fluid is pentane.

35. An organic Rankine cycle power plant comprising:

a) a preheater for preheating organic liquid working fluid;

b) a vaporizer for vaporizing preheated liquid working fluid produced by said preheater;

c) a first turbine module having an input for receiving vaporized organic working fluid produced by said vaporizer and having an output shaft, said first module being responsive to vaporized organic working fluid from said preheater for expanding the organic working fluid to produce work at the output shaft and heat depleted organic working fluid that is superheated;

d) a second turbine module having an input for receiving heat depleted organic working fluid from the first module and having an output shaft, said second module being responsive to vaporized organic working fluid from said first module for expanding the organic working fluid to produce work at the output shaft and heat depleted organic working fluid that is superheated, the turbine efficiency of the second turbine module being higher than the turbine efficiency of the first module;

e) an electric generator located between said modules and coupled to their output shafts; and

f) a condenser for condensing heat depleted organic working fluid produced by said second module into condensate; and

g) means for supplying said condensate to the preheater.

36. An organic Rankine cycle power plant according to claim 35 wherein said second turbine module comprises at least one turbine stage whose last stage is effective to substantially isolate upstream stages of said second turbine module from changes in back pressure on the second module.

37. An organic Rankine cycle power plant according to claim 36 wherein the Mach number of the last stage in the second turbine module is around 1.2 for substantially isolating the upstream stages of said second turbine module from changes in back pressure.

38. Apparatus according to claim 35 wherein said organic working fluid is pentane.

64. A power plant according to claim 35 wherein the electric generator positioned between the modules permits the generator to be directly driven by the output shafts of the modules at the same rotational speed as the modules at a relatively low speed.

65. A power plant according to claim 64 wherein the relatively low speed is 1800 RPM.

39. Apparatus for producing power comprising:

(a) a plurality of systems each of which has;

(1) a preheater for preheating organic liquid working fluid;

(2) a vaporizer for vaporizing preheated organic liquid working fluid produced by said preheater;

(3) a pair of multi-staged turbine modules each of which has an input for receiving vaporized organic working fluid and an output shaft, each module being responsive to vaporized organic working fluid applied to its input for expanding the working fluid and producing work at its output shaft and heat depleted working fluid that is superheated;

(4) an electric generator located between said modules and coupled to the their output shafts;

(5) means for supplying superheated, heat depleted organic working fluid produced by one of the pair of modules to the input of the other of the pair of modules;

(6) the turbine efficiency of said other of the pair of modules being higher than the turbine efficiency of said one of the pair of modules;

(b) means for supplying medium or low temperature fluid from a low grade heat source to all of the vaporizers of said systems in series to produce heat depleted source fluid; and

(c) means for supplying heat depleted source fluid to all of the preheaters of the systems in parallel.

40. An organic Rankine cycle power plant according to claim 39 wherein the other of the modules of each pair comprises at least one turbine stage whose last stage is effective to substantially isolate upstream stages from changes in back pressure.

41. An organic Rankine cycle power plant according to claim 40 wherein the Mach number of the last stage in the second turbine module is around 1.2 for substantially isolating the upstream stages from changes in back pressure.

42. Apparatus according to claim 39 wherein said organic working fluid is pentane.

43. Apparatus for producing power according to claim 39 wherein said medium or low temperature fluid from said low grade heat source is geothermal fluid.

44. Apparatus for producing power according to claim 43 wherein said geothermal fluid is geothermal water.

68. Apparatus according to claim 43 wherein the electric generator positioned between the modules permits the generator to be directly driven by the output shafts of the modules at the same rotational speed as the modules at a relatively low speed.

69. Apparatus according to claim 68 wherein the relatively low speed is 1800 RPM.

47. A method for producing power comprising the steps of:

a) supplying medium or low temperature fluid from a low grade heat source to a plurality of systems each of which has;

(1) a preheater for preheating organic liquid working fluid;

(2) a vaporizer for vaporizing preheated organic liquid working fluid produced by said preheater;

(3) a pair of multi-staged turbine modules each of which has an input for receiving vaporized organic working fluid and an output shaft, each module being responsive to vaporized organic working fluid applied to its input for expanding the working fluid and producing work at its output shaft and heat depleted working fluid that is superheated;

(4) an electric generator located between said modules and coupled to the their output shafts;

(5) means for supplying superheated, heat depleted organic working fluid produced by one of the pair of modules to the input of the other of the pair of modules;

(b) supplying medium or low temperature fluid from a low grade heat source to all of the vaporizers of said systems in series to produce heat depleted source fluid; and

(c) supplying heat depleted source fluid to all of the preheaters of the systems in parallel.

48. A method according to claim 47 wherein the step of supplying medium or low temperature fluid from said low grade heat source to the plurality of systems is carried out by supplying geothermal fluid to the plurality of systems.

49. A method according to claim 48 wherein the step of supplying geothermal fluid to the plurality of systems is carried out by supplying geothermal water to the systems.

53. A method according to claim 47 wherein the step of positioning an electric generator between the modules permits the generator to be directly driven by the output shafts of the modules at the same rotational speed as the modules such that the modules rotate at a relatively low speed.

54. A method according to claim 53 wherein the relatively low speed is 1800 RPM.

80. Apparatus for producing power comprising:

a) a pair of multi-staged turbine modules each of which has an input for receiving vaporized working fluid and an output shaft, and each of which is responsive to vaporized working fluid applied to its input for expanding the working fluid producing heat depleted working fluid and driving the output shaft;

b) an electric generator located between said modules and directly coupled to their output shafts for driving the generator at the same speed as the turbine modules; and

c) means for supplying heat depleted working fluid from one of the modules to the input of the other of the modules.