6. A fuel contains the following percentage of combustibles by mass C: 84%, H2 : 4.1 %. If the air used from burning of coal in a boiler is 16.2 kg per kg of fuel, find the total heat carried away by dry flue gases if they escape at 300C. The specific heats of CO., Oz, Nz are 0.892, 0.917 and 1.047 respectively. Find the minimum amount of air required from the complete combustion of 1 kg of this fuel and the excess O, supplied. [Ans. 4806.68 kJ, 11.16, 1.158]