A. Stoichiometric combustion air
B. Non-preheated combustion air
C. Combustion air not enriched with oxygen
D. Recuperators
Related Mcqs:
- 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 - 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 - 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. - 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 - 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. - An improved and fuel efficient version of the pusher type reheating furnace is the ______________ furnace?
A. Walking beam
B. Shaft
C. Tunnel
D. Rotary hearth - While the fuel fired furnace can be used upto a maximum temperature of about 1700°C, the electric furnace can be used upto a temperature of about _____________ °C?
A. 2000
B. 3000
C. 4500
D. 6000 - Protective gas used in the annealing furnace for steel coil comprises of__________________?
A. 95% N2 + 5% H2
B. 5% H2 + 9% N2
C. 100% CO
D. 100% H2 - 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 - _____________ furnace is not an electric furnace?
A. Arc
B. Induction
C. Pot
D. Resistance
