chemical engineering fuels and combustion MCQs – Page 9

Practise multiple-choice questions from chemical engineering fuels and combustion for competitive examinations and subject revision. Review each marked answer and report any item that may be outdated or unclear.

chemical engineering fuels and combustion Mcqs

161. 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?
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A. 105

B. 145

C. 85

D. 70

162. Pitch creosote mixture (PCM) as compared to furnace oil is a better fuel, because its ___________________?
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A. Emissivity factor is higher

B. Flue gas has lower dew point thereby facilitating more waste heat recovery

C. Sulphur content is lower

D. All A., B. and C.

163. The gas which contributes maximum to the heating value of natural gas is __________________?
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A. CO

B. CH4

C. CO2

D. H2

164. The maximum percentage of CO2 in a flue gas (from a carbonaceous fuel) can be_________________?
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A. 79

B. 29

C. 77

D. 21

165. The internal energy of the combustion products is ____________________ compared to that of reactants?
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A. More

B. More or less; (depends on the state of fuel.)

C. Less

D. Equal

166. Which of the following is the most important deterrents to an extended use of pulverised coal in boiler firing ?
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A. Ash disposal problem

B. Excessive fly-ash discharge from the stack

C. High power consumption in its transportation

D. Erosion of induced draft fan blades

167. Percentage of hydrogen in coke oven gas may be around ___________________?
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A. 10

B. 25

C. 60

D. 45

168. Octane number of 2, 2, 4 trimethyl pentane is __________________?
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A. In between 0 and 100

B. More than 100

C. 0

D. 100

169. Catalyst used in Fischer-Tropsch process is_______________?
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A. Alumina

B. Zinc oxide

C. Thorium oxide

D. Nickel

170. Cannel coal__________________?
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A. Is a non-banded coal which can be ignited easily with a match stick or candle flame, hence is

B. Has a high volatile matter content and burns with a luminous smoky flame

C. Is non-coking

D. All A., B. and C.

E. named

171. Which of the following has the highest calorific value (kcal/Nm3) ?
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A. Carburetted water gas

B. LPG

C. Natural gas

D. Gobar gas

172. _____________ has the widest inflammability limit (explosion limit) of all the gases?
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A. Methane

B. Hydrogen

C. Carbon monoxide

D. Acetylene

173. In case of pulverised coal fired steam boiler, the secondary air serves the main purpose of__________________?
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A. Combustion of coal by supplying it around the burner

B. Drying of coal

C. Transportation of coal

D. Preheating the primary air

174. A gaseous fuel in order to develop luminosity on burning, must contain __________________?
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A. Oxygen

B. Hydrocarbons

C. Carbon monoxide

D. Hydrogen

175. Cannel coal and boghead coal are the examples of _________________?
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A. None of these

B. Humic coals

C. Liptobiolites

D. Sapropelic coals

176. Which of the following is a poisonous fuel gas ?
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A. Coke oven gas

B. None of these

C. Blast furnace gas

D. Natural gas

177. Caking index of the coal blend used for the manufacture of metallurgical coke should be around__________________?
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A. 48

B. 5

C. 40

D. 21

178. Fat coal means a coal having ___________________?
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A. High volatile matter

B. Low ash content

C. Low calorific value

D. Non smoking tendency

179. Tolerable concentration of toxic carbon monoxide in atmospheric air is about ______________ ppm?
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A. 10000

B. 1000

C. 50

D. 5000

180. High rate of heating of coke ovens____________________?
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A. May damage its walls due to abrupt excessive swelling of coal

B. Increases the time of carbonisation

C. None of these

D. Produces larger size coke

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