Condensate pump design

[Kamakal]

Hello:
I have a steam condensate drum operating at 50 psig. I have designed a pump for this system where the destination pressure is also 50 psig. The discharge losses are around 30 psi (includes line pressure drop, exchanger and a control valve).
Should I design the pump for a differential pressure of 30 psi or 80 psi (to cater to a cold start up when the drum pressure may be very low). If I design for 80 psi delta, the pump will not operate near its best operating point during normal operations.
Is there a way out of this situation?
Thanks.

 

[TD2K]

Variable speed driver? It may not keep you at the BEP but it will keep you from wasting 50 psi (the additional dP you want to add for the cold startup case) across a control valve during normal operations.

For a cold startup, can you get rid of the condensate some way until you are up to normal (or close to it) operating pressures?

 

[quark]

I agree with TD2K on the second suggestion. Even a VSD may be redundant.

 

[Yorkman]

How about dual pumps? One rated for the cold start up with a pressure control or float switch to enable the other pump when up to operating temperature. That way you can run both at the optimum design.

I'm not a real engineer, but I play one on T.V.
A.J. Gest, York Int./JCI

 

[roker]

hello,

you can also add an expansion vessel connected to the suction with a pressure (above the diaphragm) of 50 psig.

regards,
roker