Related Mcqs:

1. Circulation of gases in furnace is caused by the_________________?

   A. Change in volume during a change of temperature
   B. Difference in density between hot and cold gases
   C. Furnace pressure in conjunction with draft in flues
   D. All A., B. and C.

2. Pulverised fuel fired furnaces employ ______________ fuel firing?

   A. Horizontal
   B. Vertical
   C. Tangential
   D. All A., B. and C.

3. Maximum heat transfer in high temperature furnaces is by____________________?

   A. Conduction
   B. Convection
   C. Radiation
   D. Either A., B. or C.; depends on the type of furnace

4. Hearth furnaces are not used for____________________?

   A. Roasting
   B. Melting
   C. Reheating
   D. None of these

5. Shaft furnaces are used for_______________________?

   A. Smelting
   B. Calcining
   C. Roasting
   D. All A., B. and C.

6. Thermal efficiency of furnaces can be improved by____________________?

   A. Waste heat recovery from flue gas
   B. Minimising heat losses from furnace walls
   C. Maintaining proper draught
   D. All A., B. and C.

7. 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

8. Thickness of stock does not affect the fuel economy of furnaces, if the material to be heated is of__________________?

   A. Low emissivity
   B. High thermal conductivity
   C. Both A. and B.
   D. Neither A. nor B.

9. Fuel economy in furnaces can be achieved by_________________?

   A. Using oxygen enriched combustion air
   B. Preheating the combustion air
   C. Reducing the heat loss through furnace openings & doors
   D. All A., B. and C.

10. Ingress of cold air in the furnaces through cracks, charging doors, openings etc ________________?

    A. Reduces the flue gas temperature and makes the furnace atmosphere oxidising
    B. Increases the load on the induced draft fan
    C. Reduces the furnace draught
    D. All A., B. and C.