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:
§ 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.
}
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
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