০১। "Overfire burning" in a furnace is a phenomenon characterised by the
ক) supply of excess fuel.
খ) supply of excess air.
গ) burning of carbon monoxide and other incombustibles in upper zone of furnace by supplying more air.
ঘ) none of these.
০২। 'Fat coals' are those coals which have very high
ক) caking capacity.
খ) volatile matter content.
গ) fusion point of its ash.
ঘ) inherent moisture content.
০৩। 'Fat' coal means a coal having
ক) low calorific value.
খ) high volatile matter,
গ) low ash content.
ঘ) non smoking tendency.
০৪। 'Fuel' can be defined as a substance which produces heat by
ক) combustion.
খ) nuclear fission.
গ) nuclear fusion.
ঘ) all (a), (b) & (c).
০৫। 'Mixed gas' used in steel plants is a mixture of
ক) B.F. gas and coke oven gas.
খ) coke oven gas and converter gas.
গ) coke oven gas and L.P.G.
ঘ) blast furnace gas and naphtha vapor.
০৬। 'Wind loss' resulting from unscientific storage of coal may be the order of about __________ percent.
ক) 2.5
খ) 7.5
গ) 10.5
ঘ) 14.5
০৭। 'Wobbe index' is a characteristic of
ক) solid fuels
খ) gaseous fuels
গ) liquid fuels
ঘ) fat coals
০৮। (64-132) rank coal (ASTM) means a coal with 64%
ক) fixed carbon and having a heat value of 13, 200 BTU/1b.
খ) ash and a heating value of 13, 200 BTU/1b.
গ) fixed carbon and a heating value of 132 BTU/1b.
ঘ) none of these.
০৯। (64-132) rank coal (ASTM) means a coal with 64%
ক) fixed carbon and having a heating value around 13, 200 BTU/1b.
খ) ash and heating value around 13, 200 BTU/1b.
গ) fixed carbon and heating value around 132 BTU/1b.
ঘ) none of these.
১০। A carbonaceous fuel (containing no H2 or hydrocarbons) is burnt and the resulting flue gas contains 21% CO2. It means that
ক) 21% excess air has been used for combustion.
খ) 21% excess oxygen has been used for combustion.
গ) complete combustion of fuel has taken place.
ঘ) no excess air has been used for combustion.
১১। A certain thickness of the coal, if stored unscientifically on soft (katcha) ground having no metallic/concrete flooring gets sunked into the ground, which is termed as the 'carpet loss'. The carpet loss may be of the order of __________ cms.
ক) 1 to 2
খ) 3 to 4
গ) 5 to 15
ঘ) 20 to 40
১২। A coal containing high amount of volatile matter will have
ক) low ignition temperature
খ) very little ash content
গ) high fusion point of its ash
ঘ) low adiabatic flame temperature
১৩। A coal containing very high percentage of durain is called __________ coal.
ক) bright
খ) splint
গ) non-banded
ঘ) boghead
১৪। A coal gasifier opearating at 20 atm. (e.g. Lugri gasifier) as compared to one operating at atmospheric pressure (e.g. Kopper-Totzek or Winkler gasifier) will produce a gas having
ক) higher methane content and thus higher calorific value.
খ) higher carbon monoxide content.
গ) lower carbon dioxide content.
ঘ) none of these.
১৫। A coal having high amount of volatile matter
ক) would require smaller combustion chamber.
খ) produces very little of tar and gas on carbonisation.
গ) ignites easily and burns with long smoky flame.
ঘ) all (a), (b) and (c).
১৬। A coal having high ratio of volatile matter to fixed carbon as compared to a coal having low ratio of volatile matter to fixed carbon
ক) is less liable to spontaneous combustion on storage.
খ) is more difficult to ignite and produces a shorter flame.
গ) requires smaller combustion space and less secondary air.
ঘ) none of these.
১৭। A coal having high volatile matter content will
ক) give less yield of tar and gas on carbonisation.
খ) burn with a small non-smoky flame.
গ) have a very high calorific value.
ঘ) none of these.
১৮। A coal having higher volatile matter content will necessarily have lower
ক) ash fusion temperature.
খ) calorific value.
গ) ignition temperature.
ঘ) caking index.
১৯। A coal having higher volatile matter content, has lower
ক) smoking tendency on burning.
খ) coke oven gas yield on carbonisation.
গ) chance of catching fire during storage in open space.