19
21
23
29
✅ The correct answer is option C.
Chemical Engineering MCQs
Producer gas containing least amount of tar is produced by the
Partial combustion of coal
Partial combustion of large size (< 50 mm) coke
High pressure gasification of coal (e.g. in Lurgi gasifier)
Atmospheric pressure gasification of coal (e.g., in Kopper-Totzek gasifier)
✅ The correct answer is option B.
Froth floatation is used for
Washing fine coal dust (< 0.5 mm size)
Washing lump coal (> 80 mm size)
Removing ash from the coal based on difference in specific gravity of coal and ash
All of the above
✅ The correct answer is option A.
Coals used for the generation of producer gas should have
High caking index
Low fusion point of ash
High volatile matter content
Very low ash content (8-10%)
✅ The correct answer is option C.
The main drawback of supplying more excess air in the combustion of fuel is the
Excessive power requirement of air blower
Enhanced sensible heat loss in the flue gas
Intermittant and uncontrolled combustion of the fuel
High exit flue gas temperature from the furnace
✅ The correct answer is option B.
Hard coke is manufactured from
Lignite
Bituminous coal
Semi-anthracite
Anthracite
✅ The correct answer is option B.
The main reason for making the copper calorimeter (used in bomb calorimeter) silvery white and shining/polished is to
Minimise its corrosion
Avoid radiation heat loss
Make it look attractive
None of these
✅ The correct answer is option B.
Critical Air Blast (CAB) value of coke is a direct measure of its
Reactivity
Hardness
Strength
None of these
✅ The correct answer is option A.
Naphthalene is used for making
Insecticides (e.g. moth balls)
Unsaturated polyesters
Drug intermediates e.g. β-naphthol
All of the above
✅ The correct answer is option D.
Net calorific value is the gross calorific value less the __________ heat of water in the product of combustion when cooled to 15°C.
Sensible
Latent
Sensible and latent
None of these
✅ The correct answer is option C.