Protective gas used in the annealing furnace for steel coil comprises of__________________?

Related Mcqs:

1. 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 ?

   A. 5
   B. 60
   C. 20
   D. 40

2. Ceramic coating material for furnace refractory, which increases its emissivity and thus the radiation heat transfer rate in the furnace, comprises of_________________?

   A. Graphite powder
   B. Thoria
   C. Zircon powder
   D. Beryllium

3. In practical operation of any furnace, zero oxygen percentage or theoretical CO2 percentage in flue gas is rarely achieved, because of__________________?

   A. Use of non-preheated combustion air
   B. Use of pulverised solid fuels
   C. Imperfect mixing of fuel & air and infiltration of air
   D. Use of excessive positive draft in the furnace

4. Higher furnace temperature cannot be achieved by use of a lean fuel gas in the furnace by_________________?

   A. Increasing the draft in the furnace
   B. Preheating the fuel gas
   C. Oxygen enrichment of combustion air
   D. Preheating the combustion air

5. Temperature of a furnace fired with low calorific value fuel gas (i.e. lean gas) can be increased by______________________?

   A. Preheating the combustion air
   B. Oxygen enrichment of combustion air
   C. Preheating the fuel gas
   D. All A., B. & C.

6. Fuel economy in an industrial furnace operation cannot be achieved by the use of__________________?

   A. Stoichiometric combustion air
   B. Non-preheated combustion air
   C. Combustion air not enriched with oxygen
   D. Recuperators

7. 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.

8. Furnace aerodynamics is related to the _____________ in the furnace?

   A. Movement of gases
   B. Measurement of flue gas volume
   C. Temperature control
   D. Pressure adjustment

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. _____________ furnace is not an electric furnace?

    A. Arc
    B. Induction
    C. Pot
    D. Resistance