In a heat treatment shop, steel components are heat-treated in batches of 80 Tons. The
heat treatment cycle is as follows;
Increase temperature from 30 OC to 850 OC in 3 hours.
Maintain 850 OC for 1 hour (soaking time).
Cool the material to 60 OC in 4 hours.
a) Calculate the efficiency of the furnace, if the specific heat of steel is 0.12 kcal/kgOC
and fuel oil consumption per batch is 1400 litres.
GCV of fuel oil - 10200 kcal/kg,
Cost of fuel oil - Rs. 46,000/kL,
Sp. gr. of fuel oil - 0.92.
b) Due to high cost of oil, the plant management decides to convert to a lower operating
cost LPG fired furnace lined on the inside with ceramic fibre insulation and with an
operating efficiency of 80%, for same requirement. The investment towards installation of
the new furnace is Rs. 50
heat treatment cycle is as follows;
Increase temperature from 30 OC to 850 OC in 3 hours.
Maintain 850 OC for 1 hour (soaking time).
Cool the material to 60 OC in 4 hours.
a) Calculate the efficiency of the furnace, if the specific heat of steel is 0.12 kcal/kgOC
and fuel oil consumption per batch is 1400 litres.
GCV of fuel oil - 10200 kcal/kg,
Cost of fuel oil - Rs. 46,000/kL,
Sp. gr. of fuel oil - 0.92.
b) Due to high cost of oil, the plant management decides to convert to a lower operating
cost LPG fired furnace lined on the inside with ceramic fibre insulation and with an
operating efficiency of 80%, for same requirement. The investment towards installation of
the new furnace is Rs. 50