Tek-Tips is the largest IT community on the Internet today!

Members share and learn making Tek-Tips Forums the best source of peer-reviewed technical information on the Internet!

Register Log in
  • Congratulations cowski on being selected by the Eng-Tips community for having the most helpful posts in the forums last week. Way to Go!

Search results for query: *

  1. stgrme

    Isentropic efficiency vs Real Manufacturer efficiency

    I have calculated Steam Turbine-Generator output and turbine overall (HP/LP) efficiency. Please see the attached PDF of my spreadsheet. You will note that I have included estimated percentages for mechanical and electrical (generator) losses based on my experience. Although the value of the...
  2. stgrme

    Condensate Pipelines

    Please note that all drains shown on the piping diagram should be from low points in each pipe segment/run. If not, the drains need to be moved to the low points. The piping diagram already shows a drain from the common line downstream of NRVs with a sealing loop, I don’t think you need to add...
  3. stgrme

    Vacuum breaker valve

    Vacuum breaking is used on large steam turbine-generators to minimize damage to the turbine-generator under certain emergency shutdown conditions. Please see the excerpt below from Westinghouse Steam Information Manual, CT-24035, August 1983, Revision 0. “Vacuum should be broken immediately...
  4. stgrme

    Main Steam Line attemperator

    Keep in mind that the operating temperature of the main steam system may be limited by the “rated” temperature of the steam turbine. Check the turbine’s nameplate for the “rated” temperature. Operating above the “rated” temperature will result in reduced creep life of the turbine. Best of luck!
  5. stgrme

    Hydraulic Supply Piping to Actuator

    A hydraulic oil system for a steam turbine is not a typical industrial application. Steam turbine manufacturers recommend piping (not hoses) up to the valve actuator due to the fire hazard if hydraulic oil sprays onto a hot surface. Lube oil, used as a hydraulic oil, as well as most synthetic...
  6. stgrme

    power plant performance

    In my experience, one of the best plant performance software packages is "PEPSE" by Curtiss-Wright. Please note that the software is expensive (probably, in excess of $20,000) and will require a lot of input data to complete an accurate model of the plant. In addition to the software package...
  7. stgrme

    Effect of operating condition on steam turbine

    I am not surprised that your steam turbine operates successfully at the off-design conditions you noted. I would not expect the turbine to trip under these operating conditions. The main consequence of operating at 18 barg and 320 °C instead of the design conditions of 40 barg and 400 °C is a...
  8. stgrme

    Condensing steam turbine,isoentropical efficiency.

    Please note that my approach is based on a GE technical bulletin from the 1960s or 1970s, GET-2685 – Estimating Performance of Automatic-Extraction Turbines. I have adjusted the efficiency based on my observations of changes in turbine efficiency over the years. Please note that an actual...
  9. stgrme

    Condensing steam turbine,isoentropical efficiency.

    I suggest using an overall isentropic efficiency (main steam inlet to exhaust) of 76% rather than individual section efficiencies as you proposed. There are several reasons for this approach. First, besides the Curtis Control Stage immediately downstream of the main steam inlet, there is a...
  10. stgrme

    Feedwater Heater Drain Sizing

    I suggest that you consult ASME TDP-1 2013, Prevention of Water Damage to Steam Turbines Used for Electric Power Generation: Fossil-Fueled Plants. This reference is a definitive guide for design and operation of drain systems to prevent turbine water induction. Please note two drains are...
  11. stgrme

    Steam Turbine 1st Wheel Blade Root Crack

    In my first response I noted that a rapid temperature drop produces thermal shock. Rapid cooling results in high thermal stresses at the surface of the metal bathed by the “cool” steam. In response to your dilemma: • I don’t know your plant processes, so I don’t know if there is any way...
  12. stgrme

    Steam Turbine 1st Wheel Blade Root Crack

    The OEM’s concern about a rapid drop in temperature upstream of the TTV may be related to a loss of fire in the boiler and/or a carryover of water with the steam (a water induction). Entry of “cooler” steam into the turbine can result in high stresses due to thermal shock. Carryover of water...
  13. stgrme

    Round Condensers

    Perhaps, "round" steam surface condensers should be more appropriately called "cylindrical" since the main body of the condenser is cylindrical. I have attached an image of a typical "round" or "cylindrical" condenser. Cylindrical condensers are usually shipped fully assembled, and therefore...
  14. stgrme

    help needed about steam turbine

    The flanges, shown in the cross-sectional diagram, are for moisture removal from upstream of the last LP stage. I have enclosed a PDF file with the holes highlighted in yellow to show the connection of the chamber above each flange to the chamber above the last stage stationary blades at each...
  15. stgrme

    water induction preventing main stop valve to work.

    Further to my earlier reply, you should obtain a copy of ASME Standard TDP-1-2013, Prevention of Water Damage to Steam Turbines Used for Electric Power Generation: Fossil-Fueled Plants. This document is the most comprehensive guide for design, operation, inspection and testing to avoid turbine...
  16. stgrme

    water induction preventing main stop valve to work.

    There are two main consequences from water inductions: damage from the impact of a "slug" of water and thermal quenching causing high thermal stresses. Impact damage to internal parts of the main stop valve could result in broken parts preventing the valve from fully closing and/or damage to...
  17. stgrme

    Chattering in Quick Closing Cold Reheat NRV (CRH QCNRV)

    I re-read the original posting from the OP. In my initial reply, I suggested that the disc (clapper) might be operating close to its closed position. However, according to the OP, damage was seen on the hinge. If the disc were operating close to its seat. I would have expected damage to the...
  18. stgrme

    Chattering in Quick Closing Cold Reheat NRV (CRH QCNRV)

    Cold reheat (CRH) check valves are required for large reheat turbines with an HP turbine bypass system. See the typical outline image file enclosed. The check valves prevent back flow into the HP turbine exhaust during start-up when CRH pressure is greater than HP turbine exhaust pressure. As...
  19. stgrme

    VWO

    Steam turbines are generally designed for continuous operation at VWO (Valves Wide Open). If the turbine has capability for 5% overpressure (5% OP), then it can run continuously at VWO with 5% OP. In some cases the generator is not designed to operate at rated power factor (pf) at VWO or VWO...
  20. stgrme

    Steam flow through spillage in turbine

    Please understand that the flow in each bleed is not related to the inside area of the bleed pipe. The formula on Page 7 of the GE document (Page 11 of the PDF) discusses the flow through the turbine blade path, not through a bleed pipe. Bleed flow is a function of the heater performance...

Part and Inventory Search

Back
Top