Question

The exhaust products from complete combustion of 1 kmol of PROPANE GAS contain 3 kmol of CO2, 4 kmol of H2O , 1 kmol of O2 and 22.56 kmol of N2 gases. Water vapor will begin to condense into liquid as the exhaust gases are cooled below (????) degrees C. Enter a integer value.

Answer 1

Let us first obtain the mole fraction of Water

Total moles = 3+4+1+22.56 = 30.56 kmol

Mole fraction of water (Ywater) = 4/30.56 =0.13

Now let us assume that the outlet is at atmospheric pressure

Partial pressure of water = Yi*P = 0.13*1 = 0.13 atm = 98.8 mmHg

Now we will make use of Antoine equation to solve this problem

Where P is in mmHg and T is in oC

substituting P = 98.8 mmHg in above equation to get T

T =51.40 ^oC

?Hence the temperature at which the water vapor will start condensing is 51 ^oC