Boiler Feed Water Pump Calculation

A feedwater pump is most often driven by an electric motor for energy efficiency.

Boiler feed water pump calculation.

Feed pumps for 1600 mw nuclear power stations are constructed for mass flow rates of up to 4000 tonnes h and feed pump discharge pressures of 70 to 100 bar. Boiler evaporation rate a. To ensure a high enough head and pressure boiler feed pumps have been arranged in series multistage pumps. Net pump flow rate boiler evaporation rate catch up capacity.

500 bhp x 34 5 8 337 60 x 1 5 52 gpm. Calculate the net flow rate of each boiler feed pump. Each pump on a boiler feed unit is sized based on the total load of boilers fed by specific pump feeds at one time. Another quick rule of thumb is that 1 10 of a gallon is needed for every boiler horsepower.

In exceptional cases the temperature of the fluid handled may be higher still. 10 calculate head at boiler safety vavle setting plus three percent 11 determine deaerator tank water temperature 12 perform npsha calculation 13 make preliminary pump selection 14 assure that shutoff head equals or exceeds three percent above safety valve setting 15 check npshr versus npsha 16 assure material compatibility chemical and. Boiler feed water pumps are commonly centrifugal pumps. The tdh of a boiler feed pump must at least be.

Typically a boiler feed pump is required to transfer feed water in a range of 200 230 f from a deaerator or boiler feed system to a boiler operating at pressures 15 300 psig depending on the boiler specifics. The size of boiler feed receivers are expressed in gross gallons. Boiler evaporation rate boiler capacity pph 500 2. The third step is to calculate the flow required for each boiler feed pump.

An 800 hp boiler will need an 80 gpm pump. For boiler feed pumps running on off the pumps are controlled by a boiler level controller. So a 500 hp boiler will need a pump capable of delivering 50 gpm.

The steam pressure of the boiler expressed as ft of water plus the piping control valve and other losses between the bfw pump and the feedwater inlet to the boiler plus a reasonable margin for off design conditions. For the example we have been using the calculation will look like this. Often two steam turbine driven turbo pump and two electric feedwater pumps are used. The receiver size on boiler feed units is typically based on the total system load of all boilers fed by the boiler feed unit with 20 minutes gross storage.