250 psi saturated steam at approximately 400 degrees F is used to pre-heat ambient air at 60 degrees F through a 100% theoretically efficient heat exchanger.
The desire is to raise the temperature of the ambient air from 60 degree F to 350 degrees F ---- I need to calculate the amount of steam energy in BTU's per minutes and lbs of steam per minute necessary to accomplish the increase in air temperature??
This is all the problem information provides other than the air is at atmospheric pressure.
How would you determine the temperature of the outlet steam from the HX?? Would it be at a low enough temperature to condense??
First determine the heat load from air stream:
m is the mass flowrate of air. The problem should have provided this information. But because I cannot find it here, I'm going to assign a value of 100 lb/min. You will need to change it to the desired flowrate later on.
c = specific heat of air = 0.24 (Btu/lbF)
deltaT = ...
This solution describes pre-heating of combustion air.