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Recent content by MisterDonut

  1. MisterDonut

    Steam Traps

    Thermodynamic traps are typically a good choice for high pressure steam main condensate removal, including superheat conditions. Not so good for low pressure or high back pressure. They can also be used on steam tracing. Float traps are the first choice for draining of most heating and process...
  2. MisterDonut

    HHV and LHV

    The usual convention is to rate boiler efficiency on HHV basis, whether or not it is designed to operate in a condensing mode. Combustion turbines are frequently rated on LHV basis.
  3. MisterDonut

    Outlet static pressure of a Gas Turbine

    The pressure at the outlet is dependent on the configuration of the stack, etc., on the discharge. A simple stack has a lower pressure drop across it that a heat recovery steam generator. What the manufacturer probably means is that the performance listed is based on 200 mmH20 static pressure at...
  4. MisterDonut

    compressed air drip leg

    Yes drip leg. The dryer will work most of the time. The drip leg is useful for upset conditions in the dryer and for removing sediment or other contamination.
  5. MisterDonut

    Turbine Steam Usage problem

    MPPH is thousands of pounds per hour, like stgrme said. MMPH is not equivalent to lbs/bhp/hr.
  6. MisterDonut

    Putting three way valves in a variable flow system.

    In a variable flow system, sparing use of three-way valves is a technique used to maintain a minimum of flow throug the pumps at all times. This is not unusual and should work fine if applied correctly. The flow throught the three-way valves in the bypass position should only be enough to...
  7. MisterDonut

    Condensate load

    Yes, 300 lb/hr is conservative. The likely pump selection would be at least 1.2 gallons per minute.
  8. MisterDonut

    Condensate load

    If the condensate pump is pumping out of a tank that is vented to atmosphere, then some of the steam will be lost to flashing. The amount of flash loss depends on the pressure upstream of the trap. 300 lb/hr is a conservative number. The rated flow rate for the pump might be two times the steam...
  9. MisterDonut

    Heat Rejected from boiler into boiler room

    BronYrAur, 200,000 BTU/hr appears correct. Also make sure you are satasying applicable mechanical and fuel gas codes. Example: International Mechanical Code requires 1 CFM per 2400 BTU/HR fuel input for ventilation/combustion air/dilution air.
  10. MisterDonut

    Temperature of Steam After it goes through a PRV

    The steam will be at 400 psig but it will be "wet," meaning a mixture of saturated steam and saturated liquid.
  11. MisterDonut

    Temperature of Steam After it goes through a PRV

    The enthalpy of the system (in theory) stays the same. Some of the steam will condense.
  12. MisterDonut

    Can 3 GT's Supply 1 HRSG?

    Two-on-one CTG to HRSG has been done before, and it can work as long as both CTGs are running. If one CTG is down, the "cold" side of the HRSG has reduced circulation and possibly differential expansion. Keep in mind that an HRSG in this size range is going to be a bottom-supported unit, similar...
  13. MisterDonut

    Using PVC for condensing boiler venting. Will it melt?

    Codes might allow PVC, but that does not mean PVC is acceptable or in the ownedr's best interest in every situation. Your engineering judgement can be used to require more than the code allows. The boiler manufactuer might say that PVC is acceptable to them, but they won't take responsibility if...
  14. MisterDonut

    Relief valve rating / capacity

    I don't think you have an issue here. The relief valves are there to protect the boiler. They will not open unless the pressure in the boiler reaches the set point of the relief valve. Nothing that effects the sizing of the relief valves is changing.
  15. MisterDonut

    Relief valve rating / capacity

    If the relief valve setting are not changing, then this does not make sense. If the relief valve setting are supposed to be reduced, then the relief valves will need to be changed out and possible added to, as the size of the relief valve increases as the pressure decreases due to the increase...

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