chemical engineering MCQs – Page 299

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 Review each marked answer and report any item that may be outdated or unclear.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
5961. Because of its very high refractoriness of the order of __________ C, silicon carbide refractories are used in zinc smelting furnace, muffle furnace and for supporting the wares in tunnel kilns ?
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A. 2700

B. 2400

C. 1800

D. 2200

5962. Lessing ring is formed by the addition of a partition across the centre of a raschig ring, which results in an area increase of about ______________ percent?
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A. 35

B. 55

C. 5

D. 20
5963. For the case of a fuel gas undergoing combustion with air, if the air/fuel ratio is increased, the adiabatic flame temperature will_____________________?
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A. Decrease

B. Increase or decrease depending on the fuel type

C. Not change

D. Increase

5964. Refractory materials are never used in the construction of _________________?
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A. Orton cones

B. Segar cones

C. Ovens & retorts

D. Pressure vessels
5965. Critical Air Blast (CAB) value of coke is a direct measure of its__________________?
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A. None of these

B. Strength

C. Hardness

D. Reactivity
5966. Moisture loss is determined by the _______________________?
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A. Humidity of combustion air

B. Moisture content of fuel

C. Both A. and B.

D. The water formed by combustion reaction

5967. A good metallurgical coke should have very low__________________?
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A. Sulphur & phosphorous content

B. Hardness & strength

C. Fusion point of its ash

D. Porosity

5968. During coal carbonisation process, the conversion of semi-coke to coke is accompanied by an increase in the _______________ of the mass?
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A. Density

B. Electrical resistivity

C. Porosity

D. None of these

5969. A coal having higher volatile matter content will necessarily have lower____________________?
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A. Ash fusion temperature

B. Calorific value

C. Caking index

D. Ignition temperature
5970. Which of the following would require maximum amount of % excess air for complete combustion ?
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A. Lump coal (fixed on chain grate)

B. Pulverised coal

C. Coke oven gas

D. Furnace oil

5971. Which of the following gaseous fuels is likely to have the highest gross calorific value ?
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A. Sewage gas

B. Producer gas

C. Natural gas

D. LPG
5972. A coal having high ratio of volatile matter to fixed carbon as compared to a coal having low ratio of volatile matter to fixed carbon _________________?
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A. Requires smaller combustion space and less secondary air

B. Is more difficult to ignite and produces a shorter flame

C. None of these

D. Is less liable to spontaneous combustion on storage

5973. With increase in the time of carbonisation at a particular temperature (say 1000C), the ______________ percentage in coke oven gas increases?
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A. Hydrogen

B. All A., B. and C.

C. Methane

D. Unsaturated hydrocarbons

5974. A fuel with high heat release rate will_________________?
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A. Require smaller combustion chamber

B. None of these

C. Have high calorific value

D. Have high adiabatic flame temperature

5975. Preheating of ______________ the flame temperature?
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A. The gaseous fuel before combustion decreases

B. Combustion air decreases

C. Either the fuel or the air or both, increases

D. Either the fuel or the air does not affect

5976. Eschka mixture, which is used for the determination of sulphur in coal, is a mixture of _____________________?
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A. MgSO4 & BaCl2

B. MgCO3 & NaCl

C. MgO & Na2CO3

D. BaSO4 & NaCl

5977. Firing temperature is minimum (1250-1400 C) for _______________ bricks?
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A. Fireclay

B. Silica

C. Direct bonded basic

D. Magnesite

5978. Turndown ratio of a gas burner is equal to the __________________ ?
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A. Maximum to minimum heat input ratio

B. Maximum to minimum permissible gas flow rate

C. Both A. & B.

D. Minimum to maximum heat input ratio

5979. Maximum water percentage in refractory mix meant for hand moulding may be as high as _____________ percent?
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A. 12-Jul

B. 7-May

C. 14-20

D. 3-Feb

5980. Blast furnace gas burns with a bluish flame, because of the presence of____________________?
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A. CH4

B. CO2

C. S

D. CO