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  1. dougarthur42

    Oil leak inside 9A5 generator

    I am not exactly familiar with your generator but may have some useable info. We use a vapor extractor on our lube oil tank which pulls(keeps) a slight negative pressure (vacuum)on the tank. This makes it so return lube oil cannot build up enough pressure to enter the air chambers. Any loose...
  2. dougarthur42

    Boiler feed water pump Vibration

    Just a couple things to ponder. Could the turbine be operating at or near its critical speed. We have a multistage unit that has 2 critical speeds 1 at about 2120 and another at almost 3000 rpm. It shakes like crazy at these speeds but settles out well above or below these speeds. It is not...
  3. dougarthur42

    Cladding / Thermal Spray Removal From Boiler Tubes

    yes Again
  4. dougarthur42

    Boiler tube in air path

    I would worry more about other erection mistakes, if this one was made , what else. Boiler water wall tube coming in contact with incoming secondary air should be no problem functionally. But you stated air gas path which I assume is in the flue gas exit pass, which could cause a problem. If it...
  5. dougarthur42

    circulating fluidized bed combustion

    Depending on what size unit you want probably not much. As an operator of a vintage first generation pyropower (now Foster wheeler)CFB built in 1989 twin boilers, a lot has changed since then. Some now have intrex loop seal heat exchangers, and others have plates in stead of hot cyclones and...
  6. dougarthur42

    HOGGING EJECTOR

    A hogging ejector is a steam turbine ejector that evacuates air and creates a vacuum on a condenser. Their are vacuum ejectors that pull vacuum and help a thermal turbine unit work. A hogging ejector is a larger than normal ejector used when starting up and during heavy loads. Usually they are a...
  7. dougarthur42

    Steam turbine - sudden temperature change

    I am definitely not an expert on turbines but I have experience. We operate a turbine with 3 boilers in parallel. 2 of them operate at 400kpph of flow @950* f while the other operates at 600kpph of flow @865*f. Our normal turbine inlet temps is around 905 to 915*f. However if the bigger unit...
  8. dougarthur42

    gas-tight flap after steam turbine

    A gas tight flap would be a check valve non return on the extraction. This is because if there is a turbine or extraction trip(shutdown) then you don't want water or steam to enter the turbine in this way. Many turbines have a bypass which takes an amount of steam and bypasses it directly to the...
  9. dougarthur42

    proper nomenclature - WHRSG or WHRB

    Yes HRSG Heat Recovery Steam Generator is the term. I agree a boiler is a fired vessel. In a paper mill(where I work) we have a Kraft Recovery Boiler which is a fired vessel of special design.
  10. dougarthur42

    Steam expansion at turbine lowers its pH. Why?

    I would like to know how you take Ph of superheated steam. You may be taking a sample of steam, condensing it then taking ph of the liquid condensate. Normally a ph value is present in the steam drum of the saturated steam. Volatile chemicals are added to the boiler water before it boils, these...
  11. dougarthur42

    Steam expansion at turbine lowers its pH. Why?

    It doesn't. chemicals in the boiler water are needed to assure proper condensate ph.
  12. dougarthur42

    Steam turbine vacuum keeps worsening

    at least here 28.5 in/hg is better than 24.5in hg.
  13. dougarthur42

    Steam turbine vacuum keeps worsening

    Vacuum is also directly proportional to temperature in the back end of the turbine and the condenser and may also be related to hot well level. more info is need for sure. We also have a 110 Mw steam turbine unit and condensate, it operates better with 1 vacuum pump than with 2. When the second...
  14. dougarthur42

    Steam-to-water HX pressure relief, vacuum breaking, and air removal

    Sounds like you have what you need, if the Hx is rated for SH steam. You should have a pressure relief valve on the inlet or shell side to prevent over pressure, that part is true. automatic air vent is not needed. upon initial start up you will need to bleed or drain out any excess air from...
  15. dougarthur42

    Ash and Bed Material in Circulating Fluidized Bed Boilers

    I will try to answer to the best of my ability. I am familiar with cfb's and co firing coal and petcoke. A lot of CFB operation is difficult to understand. First of all your fuel mix looks about right, you don't want any more petcoke to coal ratio than what you have. Yes the amount of bed is...
  16. dougarthur42

    Steam drum supported by downcomer

    The downcomers should not be structural support for the drum. Boilers are built so that the steam drum is hung from structural steel, The down comers are hung from the drum and not supported from below. They must be able to be allowed to expand and contract. A boiler will grow downward a few...
  17. dougarthur42

    Fuel Gas Bolier Tested with N-1 Burner

    This is just my experience We actually operate 2 boilers one with 4 burners and one with 3 burners. The one that has 4 burners has 2 above another 2 and we can get full load with one out of service. But we had trouble with the other, it has 3 burners side by each. When firing 3 burners and...
  18. dougarthur42

    Cooling tower De-Icing problems

    I don't think you can avoid ice buildup in cold climates. I work in Maine and we run our cooling tower summer and winter and it ices up in winter. All comments above are good ideas. We shut down our fans and just let the hot(75*) water break up the ice with not much air flow. Another way is that...
  19. dougarthur42

    replace speed control switch of hunter ceiling fan

    If you used 14 AWg for the repair and the orig was 18 then you have more current carrying capacity. The speed wiring of the fan should be in the wiring of the motor itself not the switch so the switch should have no bearing on fan speed. 120 volts across a certain number of wiring coils produces...
  20. dougarthur42

    Temperature of Steam After it goes through a PRV

    If the 600# steam is at saturation is is about 488*f. When you reduce the pressure you are not reducing the temperature so the 400# steam should be slightly superheated still around 488*f. Unless you desuperheat it it will remain hotter than saturation. Another point to ponder if enthalpy is...

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