Gas Usage Combustion Air, Fuel Gas and Flue Gas of Fired Heater Calculation
Fluid Flow Rate(Q, MMBtu/hr):
Fuel Gas Comp.:
CH4(mol%):
C2H6(mol%):
C3H8(mol%):
Excess Air(ea,%):
Heater Efficiency (eff,%):
Result
lb/hr MMscfd
Fuel Gas Rate:
Combustion Air Rate:
Flue Gas Rate:
Flue/MMbtu(lb/MMbtu) check with GPA Fig 8-24
Fuel Gas LHV (LHV, Btu/scf)
Fuel Gas MW(MW, lb/mol)

Heater Fuel Gas Combustion Air and Flue Gas flow Rate
CH4 + 2 O2 --> CO2 + 2 H2O
C2H6 + 3.5 O2 --> 2 CO2 + 3 H2O
C3H8 + 5 O2 --> 3 CO2 + 4 H2O
Mass flow (lb/hr) =
MMscfd * 106 * MW / 24 * 379.46





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