chemical engineering fuels and combustion MCQs – Page 12

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 Review each marked answer and report any item that may be outdated or unclear.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
221. The ratio of maximum adiabatic flame temperature in air to that in pure oxygen is always___________________?
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A. Unpredictable

B. > 1

C. 1

D. < 1
222. Coal is heated in absence of air for 7 minutes at a temperature of about ______________ C, during its volatile matter determination for proximate analysis?
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A. 550

B. 750

C. 950

D. 1150

223. Coking coals are invariably____________________?
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A. Lignites

B. Anthracites

C. Bituminous coals

D. Semi-anthracites

224. Naphthalene recovered from coke oven gas is used___________________?
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A. As moisture proof coating on fibres

B. As moth balls (insecticides)

C. As a fuel in furnaces

D. For making electrodes

225. Which of the following is the most reactive (as regards the formation of CO + H2 from C + H2O) ?
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A. Sub-bituminous coal

B. Blast furnace coke

C. Anthracite coal

D. Low temperature coke
226. Actual flame temperature is always lower than the adiabatic flame temperature, because there is________________?
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A. No possibility of obtaining complete combustion at high temperature

B. Always loss of heat from the flame

C. Both A. and B.

D. Neither A. nor B.

227. Which of the following gaseous fuels has the highest net calorific value (kcal/Nm3) ?
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A. Liquefied petroleum gas

B. Natural gas

C. Carburetted water gas

D. Producer gas

228. During the carbonisation of coal__________________?
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A. All A., B. and C.

B. All tar is evolved at 700C

C. Hard semi-coke starts shrinking at 600C

229. Washing of coal________________?
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A. All A., B. and C.

B. Improves its coking properties

C. Reduces its sulphur and ash content

D. Controls its ash fusibility and increases its calorific value

230. Fossil fuels mean___________________?
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A. Solid fuels

B. Liquid fuels

C. Premature fuels with low calorific value

D. Those fuels which are found in the crust of earth
231. Ultimate analysis of coal determines its _______________ content?
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A. Carbon, volatile matter, ash & moisture

B. Carbon, hydrogen, nitrogen & sulphur

C. Carbon, ash, sulphur & nitrogen

D. Carbon, sulphur, volatile matter & ash

232. With increases in carbonisation temperature_______________________?
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A. Coke even gas yield increases

B. Hydrogen percentage in the coke oven gas decreases

C. Tar yield increases

D. Methane percentage in the coke oven gas increases

233. Pure carbon is completely burnt in oxygen. The flue gas analysis is 70%CO2, 20%CO and 10%O2. The percent excess oxygen used is __________________?
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A. 10

B. 12.5

C. 0

D. 20

234. Mixed gas used in steel plants is a mixture of___________________?
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A. Coke oven gas and L.P.G

B. Coke oven gas and converter gas

C. B.F. gas and coke oven gas

D. Blast furnace gas and naphtha vapor

235. Insitu theory and drift theory are related to the____________________?
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A. Coalification

B. Origin of coal

C. Variation of coal quality with depth

D. Origin of petroleum oil

236. Which adsorbent is used for removing sulphur compounds (S Q, H2S, RSH etc.) removal from coke oven gas in by-products recovery plant ?
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A. Silica gel

B. Basalt

C. Diatomaceous earth

D. Bog iron (i.e., moist ferric hydroxide)
237. Calorific value of gobar gas (containing CH4 = 60% , H2 = 10% ; CO2 = 30%) may be about ______________ Kcal/Nm3?
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A. 1,800

B. 3,200

C. 5,400

D. 10,200

238. Low temperature oxidation of coal resulting from bad storage conditions does not decrease its______________________?
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A. Calorific value

B. Caking power

C. Hydrogen content

D. Oxygen content
239. Mineral matter content (M) and ash content A. in coal are approximately related as _______________?
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A. M = A

B. M = 2A

C. M = 1.1A

D. M = 1.5A

240. Narrow coke ovens as compared to wider coke ovens_________________?
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A. Produce smaller coke

B. Produce stronger coke

C. All A., B. and C.

D. Require less time of carbonisation