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Furnace Technology MCQ Questions & Answers

Furnace Technology MCQs : This section focuses on the "Furnace Technology". These Multiple Choice Questions (MCQs) should be practiced to improve the Furnace Technology skills required for various interviews (campus interview, walk-in interview, company interview), placement, entrance exam and other competitive examinations.

Question 1

Thermal efficiency of blast furnace stoves used for heating blast (air) may be about __________ percent.

A. 20
B. 40
C. 60
D. 80

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Question 2

Acid dew point temperature (ADT) of a flue gas produced by the combustion of a fuel containing 1% sulphur may be about __________ °C.

A. 80
B. 130
C. 180
D. 250

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Question 3

Which furnace employs preheating, heating and soaking zones ?

A. Soaking pit
B. Reheating furnace
C. Open hearth furnace
D. Cupola

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Question 4

Ceramic recuperators compared to metallic recuperators for the same duty

A. are lighter.
B. occupy more space.
C. are less costly.
D. have higher pressure differential between flue gas & air side.

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Question 5

Thickness of stock does not affect the fuel economy of furnaces, if the material to be heated is of

A. low emissivity
B. high thermal conductivity
C. both (a) and (b)
D. neither (a) nor (b)

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Question 6

Fuel used in B.F. stove is

A. pulverised coal
B. furnace oil
C. blast furnace gas/mixed gas
D. coke oven gas

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Question 7

An example of shaft furnace is the

A. L.D. converter
B. glass melting tank
C. blast furnace
D. soaking pit

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Question 8

Which of the following is not a directly fired furnace ?

A. By-product coke oven
B. Calcination kiln
C. Sintering furnace
D. Open hearth furnace

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Question 9

Calcination of limestone to produce lime is done in a __________ kiln.

A. tunnel
B. rotary
C. vertical shaft
D. both (b) and (c)

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Question 10

In a muffle furnace, the muffle

A. retards the heat transfer.
B. assists in temperature equalisation in the charge.
C. permits the use of controlled atmosphere for the protection of stock.
D. all (a), (b) and (c).

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Question 11

Maximum heat transfer in high temperature furnaces is by

A. conduction
B. convection
C. radiation
D. either (a), (b) or (c); depends on the type of furnace

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Question 12

Regenerators are installed in

A. coke ovens
B. open hearth furnace
C. both (a) & (b)
D. neither (a) nor (b)

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Question 13

Means for giving direction to the circulation of gases in furnaces are

A. fans.
B. arrangement of heating stock in the furnaces.
C. location of outlet ports and heating & combustion devices.
D. all (a), (b) and (c).

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Question 14

Which is a continuous furnace ?

A. Coke ovens
B. Annealing furnace
C. Glass tank furnace
D. None of these

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Question 15

Which of the following is a heat treatment furnace ?

A. Muffle furnace
B. Annealing furnace
C. Reheating furnace
D. Rotary kiln

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Question 16

Which is the most thermally efficient furnace ?

A. Reheating furnace
B. Reverberatory furnace
C. Rotary kilns
D. Boiler furnace

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Question 17

To reduce the stack loss, heat recovery from flue gas can be done by

A. preheating of cold stock.
B. preheating of combustion air.
C. steam generation in waste heat boilers.
D. all (a), (b) and (c).

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Question 18

In producer gas making furnace, steam is added along with air to mainly control the

A. fusion of coal ash & clinker formation.
B. C. V. of producer gas.
C. temperature of producer gas.
D. tar content in producer gas.

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Question 19

The purpose of controlling the furnace atmosphere is to prevent surface attack by

A. oxidation/scaling
B. decarburising
C. sulphur penetration
D. either of the above

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Question 20

Cement Kiln is a

A. rotary Kiln
B. tunnel Kiln
C. natural draft furnace
D. batch furnace

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Question 21

The thermal efficiency of an air/fuel gas preheating recuperator may be as high as __________ percent.

A. 50
B. 65
C. 85
D. 99

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Question 22

Which is not a hearth furnace ?

A. Glass tank furnace
B. Open hearth furnace
C. Cupola
D. Reheating furnace

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Question 23

Soaking pits are meant for heating steel

A. ingots
B. coils
C. sheets
D. slabs

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Question 24

Pulverised fuel fired furnaces employ __________ fuel firing.

A. horizontal
B. vertical
C. tangential
D. all (a), (b) and (c)

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Question 25

Example of an indirectly heated furnace is

A. hood annealing furnace
B. muffle furnace
C. both (a) and (b)
D. neither (a) nor (b)

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Question 26

Ceramic coating material for furnace refractory, which increases its emissivity and thus the radiation heat transfer rate in the furnace, comprises of

A. graphite powder
B. thoria
C. zircon powder
D. beryllium

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Question 27

The reason for excessive clinker formation in gas producers is the

A. use of coal/coke containing a high % of fines and ash.
B. use of fuel having too low an ash fusion temperature.
C. development of hot spots in the fuel bed and an abnormally high rate of gasification.
D. all (a), (b) and (c).

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Question 28

Which of the following is a natural draft furnace ?

A. Blast furnace stoves
B. Power plant boilers
C. Sintering furnace
D. None of these

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Question 29

Tunnel kilns are usually used for

A. roasting of pyrites.
B. drying/tempering of refractories.
C. reheating of slabs.
D. melting of glass.

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Question 30

Thermal efficiency of a limestone calcination rotary kiln may be around __________ percent.

A. 20
B. 40
C. 65
D. 80

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Question 31

Large tonnage of refractory bricks are dried in a

A. shaft furnace
B. rotary hearth furnace
C. tunnel kiln
D. muffle furnace

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Question 32

Ceramic recuperators (made of SiC) is economical, only when used for preheating combustion air above __________ °C.

A. 250
B. 650
C. 850
D. 1000

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Question 33

__________ is an indirectly heated furnace.

A. Open hearth furnace
B. Muffle furnace
C. Soaking pit
D. Reheating furnace

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Question 34

The heat recoverable from flue gases of furnaces depends on the

A. thermal efficiency of furnace.
B. quantity of flue gases.
C. flue gas temperature drop through the furnace.
D. all (a), (b) and (c).

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Question 35

An example of a periodic furnace is the

A. blast furnace stoves
B. blast furnace
C. coke oven heating chamber
D. rotary kilns

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Question 36

Heat transfer rate to the stock/charge in the furnace does not depend upon the

A. emissivity of the refactory walls.
B. size of the furance.
C. use of waste heat recovery equipments.
D. thickness of the stock.

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Question 37

The thermal efficiency of a steel slab reheating furnace (walking beam type) may be about __________ percent.

A. 15
B. 40
C. 70
D. 85

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Question 38

Which of the following is not an additive for flue gases from furnace to reduce its dew-point?

A. Ammonia
B. Fine dolomite
C. Alkaline powders
D. None of these

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Question 39

Ostwald charts are meant for

A. computing the excess/deficiency of combustion air.
B. calculation of flue gas temperature.
C. computation of flue gas analysis.
D. none of these.

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Question 40

Temperature of a furnace fired with low calorific value fuel gas (i.e. lean gas) can be increased by

A. preheating the combustion air.
B. oxygen enrichment of combustion air.
C. preheating the fuel gas.
D. all (a), (b) & (c).

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Question 41

Low stack loss indicates the

A. use of sub-stoichiometric air for combustion.
B. efficient use of fuel.
C. inefficient use of fuel.
D. oxygen enrichment of combustion air.

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Question 42

The amount of combustible escaping uncon-sumed from the furnace, depends upon the

A. air supplied and furnace temperature.
B. burner design (thoroughness of mixing versus stratification).
C. air preheat and the flow of gases in the furnace (mixing by induction, by acceleration or by change of direction).
D. all (a), (b) and (c).

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Question 43

Higher furnace temperature can not be achieved by use of a lean fuel gas in the furnace by

A. increasing the draft in the furnace.
B. preheating the fuel gas.
C. oxygen enrichment of combustion air.
D. preheating the combustion air.

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Question 44

Which of the following is the most suitable for preheating combustion air above 650°C ?

A. Regenerator
B. Metallic recuperator
C. Ceramic recuperator
D. None of these

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Question 45

Coke ovens in steel plant are heated by

A. electricity
B. blast furnace gas/mixed gas
C. coke oven gas
D. both (b) and (c)

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Question 46

__________ atmosphere is maintained inside an iron blast furnace.

A. Oxidising
B. Reducing
C. Inert
D. Decarburising

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Question 47

In a furnace employing forced draught as compared to induced draught,

A. air is sucked in, so air leaks are more and hence the furnace efficiency is reduced.
B. the fan operates hot and hence blades are liable to corrosion and erosion.
C. positive pressure exists in the furnace.
D. none of these

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Question 48

In reverberatory furnace, charge is heated mainly by

A. conduction.
B. natural convection.
C. radiation of heat from the roof of the combustion chamber.
D. none of these.

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Question 49

In order to maintain a reducing atmosphere in a furnace, it should have

A. no O2 in flue gas
B. CO in flue gas
C. high excess air
D. none of these

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