Selection of Boiler Feed Water Pump
Selection of Boiler Feed Water Pump
(OP)
Guys,
I need to design a steam generator system with two electric boilers rated at 250 kg/gr @ 8 bar pressure to deliver a total output of 500kg/hr @8 bar.I need some guidance to select the boiler feed water pump and the condensate return pump( ie flow rates,pressure,type of pump etc).What should be the margin between pump outlet pressure and boiler rated pressure? What should be the flow rate for sizing the condensate line?I was once advised it should be twice the steam rate.Any specific reasons for this? What should be the capacity for the feed water and condesate tanks?
Thanks for any help
I need to design a steam generator system with two electric boilers rated at 250 kg/gr @ 8 bar pressure to deliver a total output of 500kg/hr @8 bar.I need some guidance to select the boiler feed water pump and the condensate return pump( ie flow rates,pressure,type of pump etc).What should be the margin between pump outlet pressure and boiler rated pressure? What should be the flow rate for sizing the condensate line?I was once advised it should be twice the steam rate.Any specific reasons for this? What should be the capacity for the feed water and condesate tanks?
Thanks for any help





RE: Selection of Boiler Feed Water Pump
For large boilers which also have some excess steam drum volume to limit the upset in drum water level , one usually oversizes the BFP by 15-20% in MCR flowrate, ie, the pump design point would be flow = 120% MCR flow at a discharge pressure equal to drum MAWP plus gravity head to the drum plus feddwater and economizer piping and valve pressure losses at a flowrate of 120% MCR.
The pump actually delivered to the site usually has an additional 5% factory margin in developed head. The design pressure of piping at the outlet of the pump would be based on pump dead head pressure ( full speed at min permitted flow incuding 5% margin) divided by 1.10 .
RE: Selection of Boiler Feed Water Pump
Thanks for your post.What should be the flow rate for the Condensate return pump?
On the boiler feed water bypass line to the tank,should I use an orice plate or a pressure control valve?
RE: Selection of Boiler Feed Water Pump
Remember not to pick a feedpump that has a discharge pressure that is the same as the boiler operating pressure. No pressure drop, no flow. I've seen a number of smaller boiler installation suffer from that mistake. You should be able to get water into the boiler at the safety valve setting.
RE: Selection of Boiler Feed Water Pump
RE: Selection of Boiler Feed Water Pump
You would only need a bypass line in your boiler feed pump if the pump is vastly oversized or running continuous with a modulating feedwater valve on your boiler.
RE: Selection of Boiler Feed Water Pump
RE: Selection of Boiler Feed Water Pump
RE: Selection of Boiler Feed Water Pump
RE: Selection of Boiler Feed Water Pump
for condensate recovery schemes, you may look the site of GESTRA.
www.gestra.de
and also you must keep in mind that the condensta flow must be calculated in max. conditions - during starting up and stop of the boilers.