Fuels and Combustion

A. 0.5
B. 10
C. 50
D. 500

A. Gaseous
B. Solid
C. Liquid
D. Both B. and C.

A. Electricity
B. Coke oven gas
C. Mixed gas
D. Both B. & C.

A. Produced by low temperature carbonisation of coal
B. A domestic fuel
C. Used in blast furnaces
D. None of these

A. 10
B. 25
C. 45
D. 60

A. It is abrasive to the coal pulveriser (i.e. ball mill) and the combustion chamber
B. The ash in molten condition gets absorbed in the pores of the refractory lining of the furnace
and causes its spalling due to different co-efficient of expansion/contraction of the refractory
and the ash
C. The ash retains the sulphur & phosphorus and thus affects the quality of products in
metallurgical furnace apart from increasing the slag volume. Besides, it may fuse and stick to
the boiler tubes thereby reducing the heat transfer
D. All A., B. and C.

A. Coke oven gas
B. Producer gas
C. Blast furnace gas
D. L.D. converter gas

A. Higher than
B. Lower than
C. Same as
D. Either A. or B.; depends on the type of coal

A. Low reactivity of carbonised residue containing high proportions of iron & sulphur
B. Low forced draught and fuel bed temperature
C. Thick fire bed and preheated primary air
D. All A., B. and C.

A. Reduces its consumption in the furnace
B. Increases its consumption in the furnace
C. Does not affect its consumption in the furnace
D. Decreases its hardness and abrasion resistance