100 moles of a fuel containing methane and butane is burned

Question

1. 100 moles of a fuel containing methane and butane is burned with 25% excess air in a furnace producing stack gas at 300C and 105 kPa. Determine the amount of 100 psi saturated steam that can be produced from water fed in at 500F, if

a) the stack gas does not contain CH₄, C₄H₁₀or CO,

b) the dew point of the stack gas is 58 0C, and

c) the air enters at 200C as dry air.