271. Orsat apparatus
Gives flue gas analysis on dry basis
Determines N₂ in flue gas indirectly
Can
All of the above
✅ The correct answer is option D.
Fuel and Combustion MCQs
272. Which of the following will be unsuitable for dust cleaning from flue gas at 400°C from a pulverised coal fired boiler ?
Multicyclones
Bag filter
Wet scrubber
Hydrocyclones
✅ The correct answer is option B.
273. Main constituents of benzol are
Benzene, toluene & xylene
Tar & creosote
Ammonia & phenol
Anthracene & phenol
✅ The correct answer is option A.
274. 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
Higher methane content and thus higher calorific value
Higher carbon monoxide content
Lower carbon dioxide content
None of these
✅ The correct answer is option A.
275. Correct viscosity of furnace oil at the burner tip for proper atomisation is about 25 centistokes. To reduce the viscosity of high viscosity furnace oil (250 centistokes) to the correct atomisation viscosity (i.e. 25 cst), it should be preheated to about____°C.
70
85
105
145
✅ The correct answer is option C.
276. During coking of coal, the ash content (percentage)
Increases
Decreases
Remains constant
None of these
✅ The correct answer is option A.
277. The function of secondary combustion air is to
Pneumatically convey the pulverised coal
Completely burn the volatile matter
Burn the lumpy coal
None of these
✅ The correct answer is option B.
278. A coal that softens and fuses on heating is
Classified
Carbonised
Caking
Non-caking
✅ The correct answer is option C.
279. The sequence of absorption in flue gas analysis by Orsat’s apparatus is respectively
CO₂, O₂, CO
CO, O₂, CO₂
CO₂, CO, O₂
O₂, CO₂, CO
✅ The correct answer is option A.
280. Moisture loss is determined by the
Humidity of combustion air
Moisture content of fuel
Both A and B
The water formed by combustion reaction
✅ The correct answer is option C.