1 reply to this topic

[rsk]

I am on the assignment of sizing a boiler feed pump or pumps for total flow of 3000Tonne/hr. The boiler pressure is 43kg/cm2(g) & resistance of piping up to SG is 30m 250NB Sch 40 equivalent. At what stage i will feel to go for multistage pump in the selection process. whether it will be minimum specific speed requiring high NPSH required for a single stage pump?
Please help me in putting my fundamentals straight.
Thanks in advance

[djack77494]

rsk,
You WILL need a multistage pump for this application. While I will not condone any "rules of thumb" that say when you need/don't need to go from a single to a multi stage pump (it's a very fuzzy region), you are well into the area where a multistage pump is required. Especially in dealing with Boiler Feed Water (BFW), the worst, most unforgiving fluid in the world for pumping, you must be very conservative in your design. Do not work in a vacuum/use the pump vendor(s) for their expert advise. Most of all, ensure that you have plenty of NPSHa for this service.
Doug