Using Dulong’s formula:


 

                       =8183.98 k cal/kg.

Similarly CV of coke and tar could be calculated.   

GCV of coke = 7481.72 k cal/kg.
GCV of tar = 8775.9k cal/kg.

Calorific Value of Coke oven gas:  It can be determined by adding calorific values of all combustible components of Coke oven gas.

Combustible components of coke oven gas Heat of Combustion (k cal/kg mole) Combustible components (kg mole).   Calorific value kcal. C2 H4         297.5×103 0.4146 123.4×103 CO 67.6×103 1.796 121.4×103 H2S 123.96×103 0.3225 39.98×103

Total

 fraction of calorific value of coal in Coke

fraction of calorific value of coal in tar

fraction of calorific value of coal in coke oven gas

unaccounted calorific value of coal =1-(0.6618+0.0429+0.2172)=0.0781.
This shows that 7.81%of calorific value of coal is being utilized in raising temperatures of coke oven gas and tar to the discharge temperature.

Do Yourself

A by-product coke-oven carbonizes coal of the composition
and ash 7.5. The Coke produced contains C 88.2%, H 0.2% and ash 11.6%. Tar contains 52kg carbon.

The Coke-oven gas produced analysed

 and  

Calculate  per ton of coal.

a) Amount of coke

b) Amount of coke oven gas.

c) Fraction of calorific value of coal (a) in coke and (b) Coke- oven gas.

Answer: 

1. 647kg
2. 536  m3 (1 atm, 273 K)
3. (a) 0.63  (b) 0.34 

Those interested to solve more problems, see the following book.

1. A. Butts Metallurgical problems.