Consider combustion of fuel oil with air to heat the furnace to a temperature at Fuel oil analyses 84% C 5% H 2% S and 9% incombustibles. Gross calorific value of fuel oil is 9500 kcal/kg. Determine GAH in each case when the furnace temperature T is (a)(b)(c)(d)
Assume complete combustion with the theoretical amount of air
Solution
Basis of calculation is 1 kg fuel. Reference state of in POC is liquid and the reference temperature is
First we have to calculate the amount of POC. Combustion is complete with theoretical amount of air, POC consists of and . We can calculate the amount of each constituent of POC by the Stoichiometry of the reaction as illustrated in the lectures on combustion (Lecture 9-11). We can calculate heat carried by each constituent of POC at each temperature by using mxCpxdT. The calculated values are given in the table
POC
Sensible heat (kcal) at T =1000K
Sensible heat (kcal) T=1100K
Sensible heat (kcal) T = 1200k
Sensible heat (kcal)T = 1400K
CO2
560
652
746
937
H2O
209
222
235
261
N2
1452
1675
1903
2346
Total
2161
2549
2884
3544
GAH
7339
6951
6616
5956
Increase in temperature from 1000K to 1400K decreases GAH by Decrease in GAH is followed by increase in fuel consumption in the same proportion.
Fuel oil analyses 84% C 5% H 2% S and 9% incombustibles. Gross calorific value of fuel oil is 9500 kcal/kg. Determine GAH in each case when the furnace temperature T is (a) 
(b) 
(c) 
(d) 
in POC is liquid and the reference temperature is 
. We can calculate the amount of each constituent of POC by the Stoichiometry of the reaction as illustrated in the lectures on combustion (Lecture 9-11). We can calculate heat carried by each constituent of POC at each temperature by using mxCpxdT. The calculated values are given in the table
Decrease in GAH is followed by increase in fuel consumption in the same proportion.
