Question

Methane gas (CH₄) at 25 °C is burned steadily with dry air, which enters a combustion chamber of a natural gas boiler in a small power plant at 17 °C. The volumetric analysis of the flue gas on a dry basis is 5.2% carbon dioxide, 0.33% carbon monoxide, 11.24% diatomic oxygen, and 83.23% diatomic nitrogen. The flue gas leaves at 700 K.

a) Sketch a fully labelled schematic diagram of the system.

b) Write a balanced chemical equation for the combustion of 1 kmol of methane and hence calculate the percentage of theoretical air used.

c) Construct a property table giving the number of moles and molar enthalpies for each component involved in this combustion process.

d) Using the first law of thermodynamics, calculate the heat transfer from the combustion chamber per kmol of methane.

Answer 1