51. Octane number of 2, 2, 4 – trimethyl pen-tane is
0
100
In between 0 and 100
More than 100
✅ The correct answer is option B.
Fuel and Combustion MCQs
52. In case of pulverised coal fired steam boiler, the secondary air serves the main purpose of
Transportation of coal
Drying of coal
Combustion of coal by supplying it around the burner
Preheating the primary air
✅ The correct answer is option C.
53. Which of the following coke has the least percentage of ash?
Petroleum coke
Beehive coke
Foundary coke
Metallurgical coke
✅ The correct answer is option A.
54. Which adsorbant is used for removing sulphur compounds (S Q, H₂S, RSH etc.) removal from coke oven gas in by-products recovery plant ?
Silica gel
Diatomaceous earth
Basalt
Bog iron (i.e., moist ferric hydroxide)
✅ The correct answer is option D.
55. With increase in the temperature of carbonisation of coal
Hydrogen content of coke oven gas increases due to cracking of hydrocarbons
Methane content in the coke oven gas decreases and carbon monoxide content increases
Calorific value of the coke oven gas decreases due to cracking of hydrocarbons which is not compensated by increase in CO & H? content
All of the above
✅ The correct answer is option D.
56. Bulk density of pulverised coal may be about __________ kg/m³.
100
500
1000
1500
✅ The correct answer is option B.
57. Yield of charcoal in high temperature carbonisation of wood is about __________ percent.
10
25
50
75
✅ The correct answer is option B.
58. In low temperature carbonisation of coal, the
Yield of coke oven gas is 290 Nm³ /ton dry coal
Volatile matter in coke is zero
Temperature maintained is 700°C
Yield of tar is about 3% of dry coal
✅ The correct answer is option C.
59. Which of the following fuels is the best for burning on chain grate stoker?
Non-caking coal
Caking coal
Coking coal
Pulverised coal
✅ The correct answer is option A.
60. Which of the following gaseous fuels has the highest net calorific value (kcal/Nm³)?
Producer gas
Carburetted water gas
Natural gas
Liquified petroleum gas
✅ The correct answer is option D.