How to size a vacuum pump

[REP2]

I have a condensor that will condense steam connected to a process flash vessel. I am looking for help sizing a vacuum pump to pull a vacuum on the condensor to condense the flash steam at 25" hg. Would like to know of any references to be able to help me size a vaccum pump for this application. The flash vessel is approx 150m3.

 

[Drexl]

Hi,
What kind of process is this?
The vacuum pump is used only for removing incondensable gases so the things you need to figure out is a) how much air leakage will the system have (lots of flanges?) and b) how much non-condensable gases will come into the condenser with the steam
All the non-condensible gases will have to leave the condenser a) through the vacuum pump and in very small quantities b) dissolved in the condensate
I have not found any general guide on this, but for more specific applications such as steam turbine condensers there are some recommendations. This can also be compared to recommended venting of heat exchangers (HEI guidelines).

Drex