This document calculates the requirements for a feed pump for a boiler that produces 65 tons of steam per hour. It determines that the pump must supply 80 cubic meters of water per hour at a head of 400 meters. A pump model (RN-80_S) is selected that meets these requirements. The document then checks that the pump will not cavitate when operating at a liquid temperature of 110 degrees Celsius by calculating the net positive suction head available, which exceeds the pump's required net positive suction head.
This document calculates the requirements for a feed pump for a boiler that produces 65 tons of steam per hour. It determines that the pump must supply 80 cubic meters of water per hour at a head of 400 meters. A pump model (RN-80_S) is selected that meets these requirements. The document then checks that the pump will not cavitate when operating at a liquid temperature of 110 degrees Celsius by calculating the net positive suction head available, which exceeds the pump's required net positive suction head.
This document calculates the requirements for a feed pump for a boiler that produces 65 tons of steam per hour. It determines that the pump must supply 80 cubic meters of water per hour at a head of 400 meters. A pump model (RN-80_S) is selected that meets these requirements. The document then checks that the pump will not cavitate when operating at a liquid temperature of 110 degrees Celsius by calculating the net positive suction head available, which exceeds the pump's required net positive suction head.
This document calculates the requirements for a feed pump for a boiler that produces 65 tons of steam per hour. It determines that the pump must supply 80 cubic meters of water per hour at a head of 400 meters. A pump model (RN-80_S) is selected that meets these requirements. The document then checks that the pump will not cavitate when operating at a liquid temperature of 110 degrees Celsius by calculating the net positive suction head available, which exceeds the pump's required net positive suction head.
- Steam: 65 tons/hour (Qboiler) - Calculate feed pump? - Pressure max: 34 bar (Pboiler - Check pump’s cavitation at operation) temperature 110 degree Celsius. - Temperature max: 105 degree Celsius - Height of feed tank: 4m - Available pressure in tank: 2 bar - Suction pipe: 150 mm
T&T GLOBAL INDUSTRY AND WATER EQUIPMENT J.S.C
CALCULATION FEED PUMP FOR BOILER 65 TONS Deaerator/Condenser tank
Air vent
Pressure available: 2 bar
Typical liquid temp 105 °C.
Typical pressure 1.2 bar
T&T GLOBAL INDUSTRY AND WATER EQUIPMENT J.S.C
CALCULATION FEED PUMP FOR BOILER 65 TONS Steam Example for calculating flow and head. 70 ton/hour
From the boiler required we have the following Deaerator
information:
QBoiler = 65 tons/hour 105°C
PBoiler max = 34 bar Temp max. = 105° C
From the vapour table we have the
following data on water with a temp. of 105°C.
Density (rho) = 954,4 kg/m3 Boiler
Vapour pressure = 1,2 bar Feed pumps
T&T GLOBAL INDUSTRY AND WATER EQUIPMENT J.S.C
CALCULATION FEED PUMP FOR BOILER 65 TONS Pump sizing QBoiler 65 103 QBoiler 68,1 m 3 / h European rules according 954,4 to EN 12952-7
p Boiler 34 105 Flow: The pump has to be able to do a
hBoiler 363,18 mH 2O flow 1.15 times the max. flow on the g 954,4 9,81 boiler operation required.
Pressure: The pump has to be able to
do a pressure 1.10 times the max. QPump operation = 1,15 x QBoiler=1,15 x 68,1 = 78,31 m3/h pressure on the boiler pressure max Say: Q pump = 80 m3/h required.
hPump = 1,1 x hboiler = 1,1 x 363,18 = 399,49 m H2O
Say: H pump = 400 m H2O
Then we have FEED PUMP data is Q= 80m3/h @ H=400m
T&T GLOBAL INDUSTRY AND WATER EQUIPMENT J.S.C
CALCULATION FEED PUMP FOR BOILER 65 TONS Pump selection After we have pump spec, I select FEED pump below: - Pump model: RN-80_S - Pump flow: 80m3/h - Pump head: 400m - Pump speed: 2975rpm - NPSHreq: 4.24m
T&T GLOBAL INDUSTRY AND WATER EQUIPMENT J.S.C
CALCULATION FEED PUMP FOR BOILER 65 TONS Check pump cavitation at 110 degree C We have to calculate NPSH available at temperature 110 degree Celsius. Pa Pv Follow formula: Hsv 10 hs hl Where as: Pa: Pressure on the suction water surface (kgf/cm2) = 2 bar = 2 kgf/cm2 Pv: Pump water saturated vapour pressure (kgf/cm2) = 1,43 bar = 1,43 kgf/cm2 (at 110 degree Celsius) y: Pump liquid specific gravity [density] (kg/l) = 0,9507 kg/l (at 110 degree Celsius) hs: Suction actual head = 4m hl: Suction pipe loss head: Follow Darcy Weisbach formula L v2 4 1,2582 hl . 0,0349 0,075m D 2g 0,15 2x9,81 Vậy Hsv= 9,92m > NPSHreq= 4.24m
Conclusion: Pump operate well at liquid temperature 110 degree Celsius.