Lignite
Semi-anthracite
Sub-bituminous
Bituminous
✅ The correct answer is option B.
Fuel and Combustion MCQs
172. The lowest temperature, at which a solid fuel produces enough vapors to support continuous combustion, is called
Fire point
Smoke point
Burning temperature
Kindling temperature
✅ The correct answer is option C.
173. Coal tar fuels (CTF) as compared to petroleum based fuel oils have higher
Calorific value
Higher C/H ratio
Sulphur content
Difference in gross & net calorific value
✅ The correct answer is option B.
174. High ash coals
Are soft & friable (poor strength and size stability)
Require longer time of carbonisation as ash offers resistance to heat transfer
Produce larger quantity of coke oven gas
None of these
✅ The correct answer is option B.
175. Which of the following is coking?
Vitrain
Fussain
Both A & B
Neither A nor B
✅ The correct answer is option A.
176. Which of the following is not applicable to fluidised bed combustion of coal?
It can not burn low grade coal
It achieves higher fuel combustion efficiency
Less heat transfer surface area is required in boilers
None of these
✅ The correct answer is option A.
177. Washing of coal
Reduces its ash & sulphur content
Improves its coking properties
Increase the fusion point of its ash by removing chlorine compounds
All of the above
✅ The correct answer is option D.
178. During the carbonisation of coal
All tar is evolved at < 600°C
Evolution of H₂ and formation of methane and aromatics occur at > 700°C
Hard semi-coke starts shrinking at 600°C
All of the above
✅ The correct answer is option D.
179. Which of the following oil gasification processes is non-catalytic?
Semet-Solvay process
Segas process
Onia-Gegi process
Steam reforming of naphtha
✅ The correct answer is option A.
180. When steam is passed over coal resulting in the endothermic reaction represent by, C + H₂O = CO + H₂, it is called the __________ of coal.
Carbonisation
Oxidation
Coalification
Gasification
✅ The correct answer is option D.