Metallic recuperators are not used for waste heat recovery, if the hot flue gas temperature is above _____________ °C, because corrosion prevails at higher temperatures?

Related Mcqs:

1. Ceramic recuperators compared to metallic recuperators for the same duty_________________?

   A. Are lighter
   B. Occupy more space
   C. Are less costly
   D. Have higher pressure differential between flue gas & air side

2. Design of waste heat boiler for recovery of waste heat from furnace gases depends upon the_________________?

   A. Quantity & temperature of waste gas
   B. Dust concentration & nature of dust in waste gas
   C. Corrosive nature of the waste gas
   D. All A., B. and C.

3. Which of the following is not a continuous waste heat recovery equipment from the flue gases going out of furnace ?

   A. Economiser
   B. Regenerator
   C. Ceramic recuperator
   D. Waste heat boiler

4. To reduce the stack loss, heat recovery from flue gas can be done by_____________________?

   A. Preheating of cold stock
   B. Preheating of combustion air
   C. Steam generation in waste heat boilers
   D. All A., B. and C.

5. Ceramic recuperators (made of SiC) is economical, only when used for preheating combustion air above _____________ °C?

   A. 250
   B. 650
   C. 850
   D. 1000

6. Regenerators are used for waste heat recovery in____________________?

   A. By-product coke ovens
   B. Beehive coke oven
   C. Blast furnace stoves
   D. Soaking pits

7. Waste heat from the outgoing flue gases in a thermal power plant is recovered by a/an_________________?

   A. Economiser
   B. Steam superheater
   C. Air preheater
   D. All A., B. and C.

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

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

10. 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