Q.1

The heating capacity of continuous reheating furnace depends upon the

  • hearth area and furnace temperature.
  • emissivity of the stock.
  • ratio of wall surface to stock surface.
  • all (a), (b) and (c).
Q.2

Which is a regenerative furnace ?

  • Coke oven heating chamber.
  • Open hearth furnace.
  • Both (a) and (b).
  • Neither (a) nor (b).
Q.3

Which of the following accentuates clinker-ing troubles on furnace grate burning coal?

  • Low reactivity of carbonised residue containing high proportion of iron & sulphur.
  • Low forced draft & fuel bed temperature.
  • Thick firebed and preheated primary air.
  • All (a), (b) and (c).
Q.4

The electric furnace in which heat is produced by a combination of induced current and skin effect is called __________ furnace.

  • arc
  • resistance
  • low frequency induction
  • high frequency induction
Q.5

Ingress of cold air in the furnaces through cracks, charging doors, openings etc.

  • reduces the flue gas temperature and makes the furnace atmosphere oxidising.
  • increases the load on the induced draft fan.
  • reduces the furnace draught.
  • all (a), (b) and (c)
Q.6

Use of pulverised coal in boilers provides

  • higher calorific value
  • better combustion
  • smokeless burning
  • less erosion on furnace wall.
Q.7

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

  • no O2 in flue gas
  • CO in flue gas
  • high excess air
  • none of these
Q.8

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

  • emissivity of the refactory walls.
  • size of the furance.
  • use of waste heat recovery equipments.
  • thickness of the stock.
Q.9

Example of an indirectly heated furnace is

  • hood annealing furnace
  • muffle furnace
  • both (a) and (b)
  • neither (a) nor (b)
Q.10

Fuel used in B.F. stove is

  • pulverised coal
  • furnace oil
  • blast furnace gas/mixed gas
  • coke oven gas
Q.11

Which of the following is a natural draft furnace ?

  • Blast furnace stoves
  • Power plant boilers
  • Sintering furnace
  • None of these
Q.12

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

  • Regenerator
  • Metallic recuperator
  • Ceramic recuperator
  • None of these
Q.13

The reason for excessive clinker formation in gas producers is the

  • use of coal/coke containing a high % of fines and ash.
  • use of fuel having too low an ash fusion temperature.
  • development of hot spots in the fuel bed and an abnormally high rate of gasification.
  • all (a), (b) and (c).
Q.14

Which is the most thermally efficient furnace ?

  • Reheating furnace
  • Reverberatory furnace
  • Rotary kilns
  • Boiler furnace
Q.15

The heat recoverable from flue gases of furnaces depends on the

  • thermal efficiency of furnace.
  • quantity of flue gases.
  • flue gas temperature drop through the furnace.
  • all (a), (b) and (c).
Q.16

Coke ovens in steel plant are heated by

  • electricity
  • blast furnace gas/mixed gas
  • coke oven gas
  • both (b) and (c)
Q.17

Power required in case of forced draught as compared to induced draught (for the same draught produced) is

  • same
  • less
  • more
  • either more or less; depends on the flue gas density
Q.18

Which furnace employs preheating, heating and soaking zones ?

  • Soaking pit
  • Reheating furnace
  • Open hearth furnace
  • Cupola
Q.19

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

  • graphite powder
  • thoria
  • zircon powder
  • beryllium
Q.20

__________ is an indirectly heated furnace.

  • Open hearth furnace
  • Muffle furnace
  • Soaking pit
  • Reheating furnace
Q.21

Tunnel kilns are usually used for

  • roasting of pyrites.
  • drying/tempering of refractories.
  • reheating of slabs.
  • melting of glass.
Q.22

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

  • 15
  • 40
  • 70
  • 85
Q.23

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

  • preheating of cold stock.
  • preheating of combustion air.
  • steam generation in waste heat boilers.
  • all (a), (b) and (c).
Q.24

Soaking pits are meant for heating steel

  • ingots
  • coils
  • sheets
  • slabs
Q.25

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

  • oxidation/scaling
  • decarburising
  • sulphur penetration
  • either of the above
Q.26

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

  • Ammonia
  • Fine dolomite
  • Alkaline powders
  • None of these
Q.27

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

  • 80
  • 130
  • 180
  • 250
Q.28

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

  • 250
  • 650
  • 850
  • 1000
Q.29

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

  • fans.
  • arrangement of heating stock in the furnaces.
  • location of outlet ports and heating & combustion devices.
  • all (a), (b) and (c).
Q.30

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

  • tunnel
  • rotary
  • vertical shaft
  • both (b) and (c)
0 h : 0 m : 1 s