A. Low reactivity of carbonised residue containing high proportion of iron & sulphur
B. Low forced draft & fuel bed temperature
C. Thick firebed and preheated primary air
D. All A., B. and C.
Related Mcqs:
- 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 - Overfire burning in a furnace is a phenomenon characterised by____________________?
A. Supply of excess fuel
B. Supply of excess air
C. Burning carbon monoxide and other incombustible in upper zone of furnace by supplying
more air
D. None of these - 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 - 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. - The electric furnace in which heat is produced by a combination of induced current and skin effect is called _____________ furnace?
A. Arc
B. Resistance
C. Low frequency induction
D. High frequency induction - 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 - 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 - 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 - An electric furnace producing heat by means of an electric arc struck between each of three electrodes and the charge is called ____________ furnace?
A. Resistance
B. Arc
C. Low frequency induction
D. None of these
