chemical engineering fuels and combustion MCQs – Page 16

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 Review each marked answer and report any item that may be outdated or unclear.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
301. Which of the following is a measure of the agglutinating (i.e., binding) property of coal ?
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A. Thickness of plastic layer

B. Gray-king index

C. Swelling index

D. Caking index
302. The main product of high temperature carbonisation of coal is__________________?
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A. Coke

B. Ammonia

C. Coke oven gas

D. Tar

303. Ash content in the coke produced from a coking coal having 20% ash may be around _____________ percent?
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A. 24

B. 6

C. 12

D. 18

304. During coking of coal, the ash content (percentage)________________?
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A. Decreases

B. Increases

C. Remain constant

D. None of these

305. Sometimes water is sprayed during coal charging in the coke oven, which helps in ________________?
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A. in the gas (due to the endothermic reaction represented by C + H2O = CO + H2)

B. Controlling the dust nuisance while charging the coal

C. Prevention of clinker formation in the oven

D. All A., B. and C.

E. Reducing the cracking of hydrocarbons in the gas and increasing the percentage of CO &

306. Removal of hydrogen from coke oven gas ___________________?
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A. Increases its calorific value

B. Is not possible on commercial scale

C. Does not alter its calorific value

D. Decreases its calorific value

307. For maximum discharge through a chimney, its height should be___________________?
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A. More than 105.7 metres

B. Infinitely long

C. Equal to the height of the hot gas column producing draught

D. 200 meters

308. Yield of blast furnace gas is about _______________ Nm3 /ton of pig iron?
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A. 5000

B. 300

C. 10000

D. 2000
309. C.V. (kcal/Nm3) of gaseous fuels _____________ with increase in molecular weight?
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A. Increases

B. Decreases

C. May increase or decrease, depends on combustibles

D. Remain constant

310. As the C/H ratio of the fuel increases, the amount of CO2 formed on combustion _______________ for the same percentage of excess air?
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A. Remain same

B. Increases

C. Decreases

D. May increase or decrease depending on the type of fuel

311. Fuel combustion is never cent per cent efficient due to___________________?
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A. Dry gas/stack gas loss

B. Moisture loss

C. All A., B. and C.

D. Incomplete combustion

312. White flue gas (resembling steam) coming out of the chimney of a thermal power plant indicates that the fuel used in the boiler furnace is_________________?
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A. Tar

B. Pulverised coke

C. Pitch

D. Coke oven gas
313. Sulphur in metallurgical coal__________________?
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A. Contributes to its heating value

B. Affects the quality of steel produced as cracks develop on the surface while rolling the steel

C. Both A. and B.

D. Neither A. nor B.

314. As the equilibrium moisture content of the coal increases, its___________________?
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A. Swelling number increases

B. Calorific value increases

C. Bulk density decreases

D. Swelling number decreases
315. Adiabatic flame temperature of a fuel is dependent on the initial temperature of___________________?
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A. Fuel

B. Air

C. Both A. & B.

D. Neither A. nor B.

316. Use of excess of combustion air in the combustion of fuels results in__________________?
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A. Long flame

B. Condensation of water vapour from the fuel gas

C. None of these

D. Heat losses
317. Net calorific value is the gross calorific value less the _______________ heat of water in the product of combustion when cooled to 15C ?
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A. Sensible

B. Latent

C. None of these

D. Sensible and latent
318. High temperature in gasification of coal favours________________?
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A. High production of CO2

B. Low production of CO2

C. High production of CO

D. Both B. and C.
319. Steam is intermittently admitted into the fuel bed during the production of producer gas to__________________?
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A. Minimise the chances of clinker formation

B. Convert CO to CO2

C. Increase the gas production rate

D. Increase the combustion rate

320. Oxygen required for theoretically complete combustion of 1 Nm3 methane is ______________ Nm3?
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A. 2

B. 1

C. 6

D. 4