chemical engineering MCQs – Page 290

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 Review each marked answer and report any item that may be outdated or unclear.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
5781. Out of the following fuels, the difference between gross and net calorific value will be minimum in case of___________________?
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A. Blast furnace gas

B. Coke oven gas

C. Water gas

D. Natural gas

5782. One kg of carbon for theoretically complete combustion requires ______________ kg of air?
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A. 11.5

B. 0.5

C. 23

D. 12

5783. 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. 950

B. 750

C. 1150

D. 550

5784. Coking time in a commercial high temperature coal carbonisation plant is about ______________ hours?
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A. 6

B. 18

C. 36

D. 28

5785. Mineral matter, M and ash percentage A in coal are roughly related as_______________?
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A. M = 1.8 A

B. M = 0.5 A

C. M = 1.1 A

D. M = A

5786. Panel test determines the _____________ of refractories?
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A. Fusion point

B. Spalling resistance

C. Refractoriness under load (RUL)

D. Slag penetration resistance

5787. Froth floatation is used for_________________?
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A. Washing fine coal dust (< 0.5 mm size)

B. Washing lump coal (> 80 mm size)

C. All A., B. and C.

D. Removing ash from the coal based on difference in specific gravity of coal and ash

5788. Anthracite can be used for___________________?
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A. All A., B. and C.

B. m damage and to produce high strength coke

C. Recarbonising steel

D. Making carbon electrodes

E. Blending with highly coking coal to check its swelling which helps in saving coke even walls

5789. Higher efficiency in the combustion of solid fuel cannot be achieved by________________?
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A. Proper fuel preparation

B. Keeping the flue gas exhaust temperature very high

C. Adopting efficient-fuel firing technique & equipment

D. Supplying correct quantity of combustion air

5790. Which is not an alumino-silicate refractory ?
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A. Fireclay bricks

B. Mullite bricks

C. High alumina bricks

D. Tar dolomite bricks
5791. Too much of excess air in combustion results in high___________________?
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A. All A., B. and C.

B. Stack gas temperature

C. Fuel consumption for the same heat load

D. Percentage of oxygen in flue gases

5792. The liquid used for the washing of coal in an industrial coal washery is a mixture of water and ____________________?
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A. Carbon tetrachloride

B. Mineral oil of high viscosity & specific gravity (1.6)

C. Sand (40%)

D. None of these

5793. Periclase is___________________?
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A. Amorphous magnesite

B. MgCO3

C. ZrSO4

D. Crystalline form of MgO
5794. Ferromagnetic ceramic material is not used in the__________________?
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A. Magnetic switches

B. Transformers

C. Television sets

D. Thermal insulation
5795. Fusion point of coal ash generally varies from 1000 to 1700 C. Ash having fusion point less than _______________ C is liable to form clinker?
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A. 1100

B. 1350

C. 1400

D. 1250

5796. Porosity is induced in insulating refractories by adding________________?
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A. Powdered naphthalene

B. Calcium phosphate

C. Ammonium chloride/sulphate

D. All A., B. and C.
5797. Cermets are combination of ceramic and metallic materials due to which they have high strength & resistance to high temperature. Cermets are used in the_______________?
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A. Insulation of high temperature furnaces

B. Nuclear reactors, missiles & space crafts

C. Roof of electric furnaces

D. Hearth of the blast furnace

5798. Grog addition in fireclay during brick manufacture is done to_________________?
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A. Enhance the strength of fired refractories

B. Impart greater spalling resistance

C. Reduce its shrinkage on heating

D. All A., B. and C.
5799. A coal with high _____________ content, would ignite most easily?
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A. Fixed carbon

B. Volatile matter

C. Ash

D. Oxygen

5800. Which refractory must have controlled atmosphere (temperature and humidity) for its safe storage ?
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A. Mullite bricks

B. Tar bonded dolomite bricks

C. Magnesite bricks

D. Fireclay bricks