8. The foilowing observations were made during the trial of a boiler plant consisting of a battery of 6 lancashire boilers and an economiser: Calorific value of coal per kg= 30MJ/kg; Mass of feed...

Extracted text: 8. The foilowing observations were made during the trial of a boiler plant consisting of a battery of 6 lancashire boilers and an economiser: Calorific value of coal per kg= 30MJ/kg; Mass of feed water per kg of dry coal 9.1 kg; Equivalent evaporation from and at 100" C per kg of dry coal = 9.6 kg; Temperature of feed water to economiser 12" C: Temperature of feed water to boiler 105° C; Air temperature 13° C ; Temperature of flue gases entering economiser 370° C; Mass of flue gases entering economiser 18.2 kgkg of coal; Mean specific heat of flue gases = 1.005 kJ/kg K. %3D Find : 1. the cfficiency of the boiler alone; 2. the efficiency of the economiser alone ; and 3. the [Ans. 72.22% ; 54.43%; 84.1%l efficiency of the whole boiler plant.