Question

Calculate the higher and lower calorific values of coal sample contains 84%carbon, 1.5% sulphur, 0.6 Nitrogen, 5.5% hydrogen and 8.4% oxygen. 

Answer 1

Dulong Formula
G.C.V = 1/100[8080C + 34500(H-O/8) + 2240S] kcal/kg
= 1/100[8080*84+34500*(5.5 – 8.4/8) + 2240*1.5]kcal/kg 

= 1/100[678720+153525+3360]
= 1/100[835605]
= 8356.05 kcal/kg
∴ G.C.V = 8356.05 kcal/kg
Net calorific value = G.C.V – [ 9H/100 *587]kcal/kg
= 8356.05 – [9*5.5/100*587]
= 8356.05 – 290.57
∴ N.C.V = 8065.48 kcal/kg