Combustion of furnace oil in a furnace (soaking pit) with preheated combustion air at 400°C results in saving of about __________ percent furnace oil as compared to its combustion with atmospheric air, if the flue gas outlet temperature from the soaking pit is 1200°C ?
Correct answer: C
Explanation
Preheating the combustion air increases efficiency by reducing the required fuel energy for heating the air.