3475. Coking time in beehive coke oven is about
12 hours
2-3 days
One week
Two weeks
✅ The correct answer is option B.
3480. Rate of low temperature oxidation of coal due to bad storage conditions
Decreases with increase in surface area
Does not vary with increase in surface area
Is more for low volatile coal compared to high volatile coal
Is accelerated by storage in large heaps with small surface to volume ratio
✅ The correct answer is option D.
3484. The calorific value of producer gas is around __________ kcal/Nm³
1300
500
4500
9000
✅ The correct answer is option A.
3450. Natural draught produced by a chimney depends upon the
Density of the chimney gases
Height of the chimney
Both A & B
Neither A nor B
✅ The correct answer is option C.
3455. In high temperature carbonisation of coal compared to low temperature carbonisation
Yield of ammonia is less
Aromatic content of tar is low
H₂ content in the coke oven gas is more
Calorific value of the coke oven gas is lower
✅ The correct answer is option C.
3466. Fuel consumption in coke making can be reduced by
Preheating, blending and de-ashing the coal
Stamped charging of coal
Dry quenching of coke
All of the above
✅ The correct answer is option D.
3471. During combustion of coal on grate, clinker formation is increased by the
Use of thick fire bed
Low fusion point of ash (< 1100° C)
Use of preheated primary air
All of the above
✅ The correct answer is option D.
3476. Which of the following combustibles is absent in blast furnace gas?
H₂
CH₄
CO
None of these
✅ The correct answer is option B.
3478. Calorific value of coke even gas produced by low temperature carbonisation of coal is about __________ Kcal/Nm³.
4000
2500
6500
10000
✅ The correct answer is option C.
3483. During combustion of a gaseous fuel, the presence of a non-luminous flame is an indication of the
Incomplete combustion
Complete combustion
High oxygen in flue gas
None of these
✅ The correct answer is option B.