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 ?

Related Mcqs:

1. Flue gas outlet temperature from the chimney of any furnace should be ideally about ______________ °C?

   A. 50
   B. 100
   C. 150
   D. 250

2. Which of the following advantages is not associated with the use of preheated air for combustion of a fuel in the furnace ?

   A. Increase in calorific value of the fuel
   B. Increase in flame temperature
   C. Reduction in scale losses
   D. Saving in fuel consumption

3. In furnaces operating at very high temperature (say) 1250°C, e.g. soaking pit), the maximum heat transfer takes place by__________________?

   A. Conduction
   B. Convection
   C. Radiation
   D. Cannot be predicted

4. Out of the following fuels used in a furnace exhausting flue gas at a temperature of 600°C, the percentage stack loss will be maximum in case of complete combustion of_________________?

   A. Furnace oil with air
   B. Furnace oil with oxygen
   C. Blast furnace gas with air
   D. Blast furnace gas with oxygen

5. Advantages of use of preheated combustion air are__________________?

   A. Saving in fuel consumption
   B. Reduction in scale losses
   C. Increase in flame temperature
   D. All A., B. and C.

6. Oxygen percentage in the flue gas coming out of a gaseous fuel fired furnace should be ideally about _____________ percent?

   A. < 2
   B. < 5
   C. < 8
   D. < 10

7. Acid dew point temperature (ADT) of a flue gas produced by the combustion of a fuel containing 1% sulphur may be about ____________ °C?

   A. 80
   B. 130
   C. 180
   D. 250

8. In a furnace, the heat taken by the charge/stock and the heat lost to the furnace structure & flue gases depends on the__________________?

   A. Rate of firing and emissivity of flame
   B. Thermal conductivity of the charge & structural materials of furnace
   C. Nature of process; whether batch, continuous or intermittent
   D. All A., B. and C.

9. Which furnace employs an I.D. fan for the removal of flue gases from the furnace ?

   A. Coke oven
   B. Blast furnace stoves
   C. Beehive coke oven
   D. High pressure boiler

10. Which furnace employs preheating, heating and soaking zones ?

    A. Soaking pit
    B. Reheating furnace
    C. Open hearth furnace
    D. Cupola