HOT TOPIC HOUR

 

Valves for Combined Cycle Power Plants was Hot Topic Yesterday (June 4)

 

There was a good exchange of views among valve experts in the discussion of issues and options involving gas turbine combined cycle power plant valves. This was an organizational meeting so a range of topics covering 77 slides was addressed. The power point presentation has been posted in Power Plant Valves and Power Plant Air Quality Decisions (coal decision program), and GTCC Decisions and GTCC Supplier program.

 

GTCC Valves Decision Guide by Bob McIlvaine - Hot Topic Hour June 4, 2015

Power Point sequence used as a basis for the discussion in the June 4 Webinar.

Revision Date:  6/4/2015  Tags:  221112 - Fossil Fuel 化石燃料

Valves for Combined Cycle Power Plants Webinar - Hot Topic Hour June 4, 2015

Discussion of issues and options involving gas turbine combined cycle power plant valves.

Revision Date:  6/4/2015  Tags:  221112 - Fossil Fuel 化石燃料, Valves

 

There was agreement that the fast cycling GTCC power plants cause a real challenge for valve suppliers.  They also provide the opportunity for a unique designs to meet the challenges.  Severe service valves are customarily purchased separately from common service valves.  A number of issues were reviewed and solutions for the conditions discussed. Here are the titles of the power points and some of the details:

 

  1. Title: Combined Cycle Gas Turbine Valves: Issues and Options
  2. Table of Contents
  3. Overview
  4. What we will try to accomplish today
  5. CCJ reports turbine user group comments on valves
  6. Total Valve Solutions

§  The purchaser and supplier both benefit when the valve supplier offers a better solution rather than just a valve.

§  A good example is the Pentair pulse jet valves for gas turbine intake filters.

§  Pentair sells a solution not just a valve.

§  The selection of filter media and design depends on the ability of Pentair to clean the media.

§  So better valve systems allow consideration of different media and filter designs.

§  The valve manufacturer needs to understand the process in order to provide the best solution.

§  The same is true of fast start HRSGs and other processes.

§  McIlvaine has separate decision guides for even the nitrogen injection systems and the options for aqueous or anhydrous and the urea-to-ammonia which the Chinese prefer.

  1. Determine how valves can enhance new design HRSG
  2. Emerson Total Solution with valve and silencer
  3. Program Outline
  4. Gas Turbine Decision program
  5.  Periodic GTCC McIlvaine Valve webinar
  6. Overview of CCGT Major systems’
  7. Major valves in CCGT Water and Steam Cycle
  8. Common Valve Groupings in CCGT
  9. Specific Issues and Evaluation Considerations
  10. STEAM AND SEVERE SERVICE VALVES
  11. Specific Issues and Options for Steam Valves
  12. CCGT Severe Service Valve Requirements relative to coal plants
  13. What is severe service: Presented by Lou Sprecher of DFT

}  High pressure drop (>1000 psi), where aggressive liquids become very erosive.

}  High cycle applications including on/off service and constant modulation applications.

}  Service with entrained water droplets such as wet steam and mixed phase applications.

}  Any service that rapidly wears the valve trim causing a loss of seal or function.

}  Valves which require frequent maintenance. This can be as often as every start-up cycle

  1. Severe Service Definition (CCI)
  2. Severe Service Valves for GTCC (CCI)
  3. Combined Cycle severe service applications (CCI)
  4. Severe Service Hierarchy for Control Valves  (CCI)

24. Who should specify HP Valves

There was a discussion with Jai Jadhav of Larsen & Toubro which furnishes steam valves but not severe service throughout the world. The parent company also furnishes complete power plants and purchases severe service valves from others. L&T supplied a complete solution of HP valves for the 4,000 MW UMPP Mundra Project. There are arguments to buy severe service valves.

 

25.  Overview of CCGT Systems including hot reheat bypass valve selections

26.  Specific Issues and Evaluation Considerations

27.  Preventing cavity over-pressurization  and thermal binding (Weir presentation in McIlvaine Hot Topic Hour)

28.  29. 30. Specific Issues and Evaluation Considerations of CCOP - presented by Don Bowers, Weir

31. Velocity Related Damage Mechanisms (CCI)

32. 33. Repair vs. Replace (Arvo Eliau, Pentair)

 

Arvo Eilau of Pentair presented the following analysis done by a third party which shows the life cycle cost reduction by purchasing a better valve and repairing it rather than a cheaper valve and replacing it.

 

 

34. Specific Issues and Options for Steam Valves

35. Additional Valve Selection Resources (KSB)

36. Select Valve after you know the pump feedwater pressure

37. Do not Oversize feedwater valves

38. Specify tight shut off

39. Choices (single or dual valves for boiler feed, special purpose valves, special block and bleed)

40.  Resources (EPRI Valve Maintenance Guide for GTCC)

41.  Mogas fuse coating to base material

42. Special valve designs needed for fast cycling HRSGs (Conval)

43.  Hot reheat bypass valve selection

44. STEAM VALVE OPTIONS - Presented by Lou Sprecher of DFT

45. Severe service applications (DFT) - Presented by Lou Sprecher of DFT

46. 47. 48. 49.  DFT Control Valves flow characteristics - Presented by Lou Sprecher of DFT

 

50. Crane GTCC Valves - Presented by Brian Perkins, Crane

51. Crane Pacific Pressure Seal Y- Globe Stop-Check Valve - Presented by Brian Perkins, Crane

52. Pacific Pressure Seal – Parallel Disc Gate Valve - Presented by Brian Perkins, Crane

 

53. Pacific Forged Gate, Glove, & Check Product Design - Presented by Brian Perkins, Crane

54. Crane Nozcheck Nozzle-type Check Valve - Presented by Brian Perkins, Crane

55. Krombach Double –Offset Butterfly Valves - Presented by Brian Perkins, Crane

56. Typical Valves for Combined Cycle Plants (Flowserve)

57. Is it the glove valve design or the seal gasket and packing which prevents the leaks?

58. FUEL VALVES

59. Valve bypass eliminates liquid fuel nozzle coking (JASC)

60. Woodward supplies gas control valves for heavy frame turbines

61. MATERIALS

62. Better Alloys being used in steam valves

63. 9-12% martensitic popular but nickel alloys are expensive

64.  Incolloy 901 for stems and bushings with stellite overlay

65. COATINGS

66.  Materials expertise including EPRI Valve metallurgy guide, Special Metals product handbook
       and input from KR Mutama of TS Power

 

67.  Thermal spray coatings for ball valves (Praxair)

 

68.  Velan Secureseal Valves employ hard coatings

 

69. Stellite Delamination

 

70. NV Energy coping with stellite delamination

 

71. ACTUATORS

 

72. 73.  Pneumatic or hydraulic actuators for hot reheat bypass valves

 

74.  Electric Actuators (Rotork)  - Presented by Kathy Wilson, Rotork

 

75. Pneumatic and hydraulic actuator comparison

 

76. Hydraulic actuator premature failure

 

77. Actuator spring disc failure

 

78.  Young and Franklin electric actuator