High excess air in combustion of fuels results in____________________?

A. Increased fuel consumption
B. Incomplete combustion
C. Smoky flame
D. None of these

Very ______________ coals are completely devoid of cokability i.e., it is non-coking ?

A. Young
B. Mature
C. Both A & B
D. Neither A nor B

Incomplete combustion of a fuel is characterised by the high _______________ in the flue gas?

A. Smoke
B. Temperature
C. Oxygen
D. Carbon monoxide

Pitch creosote mixture (PCM) as compared to furnace oil is a better fuel, because its ___________________?

A. Emissivity factor is higher
B. Sulphur content is lower
C. Flue gas has lower dew point thereby facilitating more waste heat recovery
D. All A., B. and C.

Which is the most matured coal ?

A. Lignite
B. Bituminous
C. Semi-anthracite
D. Anthracite

Percentage of carbon monoxide in blast furnace gas may be around ____________________ ?

A. 8
B. 14
C. 22
D. 52

Main use of hard coke produced by high temperature carbonisation is in the ____________________ ?

A. Iron blast furnace
B. Cupola in foundries
C. Sinter making
D. Domestic ovens

For every 10% increase in the excess air; the fuel consumption increases by _______________ percent?

A. 0.1
B. 0.2
C. 0.5
D. 1.0

A coal gasifier operating at 20 atm. (e.g. Lurgi gasifier) as compared to one operating at atmospheric pressure (e.g. Kopper-Totzek or Winkler gasifier) will produce a gas having _____________________?

A. Higher methane content and thus higher calorific value
B. Higher carbon monoxide content
C. Lower carbon dioxide content
D. None of these

“Overfire burning” in a furnace is a phenomenon characterised by the __________________?

A. Supply of excess fuel
B. Supply of excess air
C. Burning of carbon monoxide and other incombustibles in upper zone of furnace by supplying
more air