chemical engineering MCQs – Page 301

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 Review each marked answer and report any item that may be outdated or unclear.

chemical engineering Mcqs
6001. Function of secondary air in pulverised coal firing is to_________________?
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A. Reduce primary air requirement

B. Dry the coal

C. Transport the coal to the burner

D. Ensure efficient burning of coal around the burner
6002. Refractory castables are used for__________________?
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A. Minimising the number of joints in the structure

B. Producing monolithic linings

C. All A., B. and C.

D. Patch work

6003. Calorific value of pitch creosote mixture (PCM) i.e., C.T.F.-200 is about________________?
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A. 25000 kcal/kg

B. 8800 kcal/kg

C. 8800 kcal/m3

D. Same as that of coal middling

6004. Emission of dense white smoke out of the chimney of a thermal power plant is an indication of the use of__________________?
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A. Too much air for combustion

B. Pulverised coal in boilers

C. Less air for combustion

D. Correct amount of air for combustion

6005. Firing of refractory brick is done to __________________?
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A. Develop stable mineral forms in them

B. duct

C. All A., B. and C.

D. Dehydrate the dried refractory

E. Form ceramic bonds necessary for development of high crushing strength in the finished

6006. Which one expands on heating ?
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A. Silica bricks

B. Fireclay bricks

C. Both A. & B.

D. Neither A. nor B.

6007. Of the total tar present in raw coke oven gas, the tar recovered in primary cooler is about _______________ percent?
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A. 25

B. 5

C. 55

D. 75

6008. ____________ of carbon blocks in the hearth of blast furnace helps in avoiding skull formation, when it becomes cold?
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A. High density

B. High thermal conductivity

C. Low porosity

D. Non-wetting characteristics
6009. Thermal spalling mainly occurs during _____________ of furnaces?
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A. Cooling down

B. Warming up

C. Both A. & B.

D. Neither A. nor B.

6010. Coal tar fuel 200 (CTF 200) is a mixture of __________________?
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A. Light oil and pitch

B. Anthracene and crecosote oil

C. Pitch and creosote oil

D. Solar oil and pitch

6011. For which pair of the fuel gases, calorific value (C.V.) of one fuel is almost double that of the other on volume basis (i.e., kcal/Nm3), while the C.V. is same on weight basis (i.e., kcal/kg) ?
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A. Propane and acetylene

B. B.F. gas and coke oven gas

C. Sewage gas and gobar gas

D. Propane and LPG

6012. Stokes equation is valid in the Reynolds number range__________________?
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A. 0.1 to 2

B. 10 to 100

C. 2 to 10

D. 0.01 to 0.1
6013. Silica bricks are never used for lining the____________________?
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A. Roof of open hearth furnace

B. Beehive coke ovens

C. Dome of blast furnace stoves

D. By-product coke ovens

6014. Which of the following is the most common pump for pumping either raw sewage or sludge ?
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A. Electromagnetic pump

B. Centrifugal pump

C. Reciprocating pump

D. Gear pump

6015. Silica refractories are not used in _________________?
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A. Beehive coke ovens

B. Dome and upper portion of B.F. stoves

C. Coke oven walls

D. Open hearth furnace roof

6016. In a/an _____________, the flow rate of fluids is obtained by measuring the difference between the impact and the static pressure?
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A. Rotameter

B. Pitot tube

C. Venturimeter

D. Flow nozzle

6017. Use of higher percentage of lime for bonding silica bricks, reduces their__________________?
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A. Strength

B. Abrasion resistance

C. Both A. & B.

D. Neither A. nor B.

6018. The velocity for subsonic flow in a pipeline_______________?
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A. Decreases in the downstream direction

B. Increases in the downstream direction

C. Is independent of the area of flow

D. Is constant

6019. With increase in the alumina content, the refractoriness of high alumina refractories_______________?
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A. Increases

B. May increase or decrease

C. Decreases

D. Remain same

6020. Which form of silica has the highest specific gravity ?
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A. Cristobalite

B. Tridymite

C. Quartz

D. All have the same specific gravity