Boiler Horsepower Calculation
Boiler Horsepower Calculation
(OP)
Hello,
I'm looking to have someone double check my calculation for the capacity of a 250 BHP boiler assuming:
Feedwater Temperature = 270 degrees F (Specific Enthalpy of the Liquid = 239.17 BTU/lb)
Steam Pressure Desired = 250 PSIG (Specific Enthalpy of Liquid = 381.76 BTU/lb, Latent Heat of Evaporation of Steam = 820.44 BTU/lb)
Boiler Horsepower = 250
So calculate the heat to raise the water to 250 PSIG Saturation Temperature:
381.76-239.17 = 142.59 BTU/lb
Calculate Total Heat:
820.44+142.59 = 963.03 BTU/lb
250*33475 = 8,368,750 BTU/hr
8,368,750/963.03 = 8,690 lbs/hr steam
But the boiler manufacturer we are talking to says that the boiler has an input of 9,900,000 BTU/hr also. This is much different than the 250 BHP rating. I guess we can discuss with them, but thoughts from my calculation based on just BHP and how BTU/hr input calculates to BHP?
Thanks.
I'm looking to have someone double check my calculation for the capacity of a 250 BHP boiler assuming:
Feedwater Temperature = 270 degrees F (Specific Enthalpy of the Liquid = 239.17 BTU/lb)
Steam Pressure Desired = 250 PSIG (Specific Enthalpy of Liquid = 381.76 BTU/lb, Latent Heat of Evaporation of Steam = 820.44 BTU/lb)
Boiler Horsepower = 250
So calculate the heat to raise the water to 250 PSIG Saturation Temperature:
381.76-239.17 = 142.59 BTU/lb
Calculate Total Heat:
820.44+142.59 = 963.03 BTU/lb
250*33475 = 8,368,750 BTU/hr
8,368,750/963.03 = 8,690 lbs/hr steam
But the boiler manufacturer we are talking to says that the boiler has an input of 9,900,000 BTU/hr also. This is much different than the 250 BHP rating. I guess we can discuss with them, but thoughts from my calculation based on just BHP and how BTU/hr input calculates to BHP?
Thanks.





RE: Boiler Horsepower Calculation
You are missing heat losses and boiler efficiency in your boiler HP calculation. That's why you need about 10MMBtu/hr to get the 250 BHP.
Regards
StoneCold
RE: Boiler Horsepower Calculation
RE: Boiler Horsepower Calculation
The boiler manufacturer is telling you the heat input required to get the output you are looking for.