Q.1

In reverberatory furnace, charge is heated mainly by

  • conduction.
  • natural convection.
  • radiation of heat from the roof of the combustion chamber.
  • none of these.
Q.2

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

  • 50
  • 65
  • 85
  • 99
Q.3

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

  • increasing the draft in the furnace.
  • preheating the fuel gas.
  • oxygen enrichment of combustion air.
  • preheating the combustion air.
Q.4

Large tonnage of refractory bricks are dried in a

  • shaft furnace
  • rotary hearth furnace
  • tunnel kiln
  • muffle furnace
Q.5

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

  • 20
  • 40
  • 65
  • 80
Q.6

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

  • fusion of coal ash & clinker formation.
  • C. V. of producer gas.
  • temperature of producer gas.
  • tar content in producer gas.
Q.7

Low stack loss indicates the

  • use of sub-stoichiometric air for combustion.
  • efficient use of fuel.
  • inefficient use of fuel.
  • oxygen enrichment of combustion air.
Q.8

Which is a continuous furnace ?

  • Coke ovens
  • Annealing furnace
  • Glass tank furnace
  • None of these
Q.9

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

  • air supplied and furnace temperature.
  • burner design (thoroughness of mixing versus stratification).
  • air preheat and the flow of gases in the furnace (mixing by induction, by acceleration or by change of direction).
  • all (a), (b) and (c).
Q.10

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

  • low emissivity
  • high thermal conductivity
  • both (a) and (b)
  • neither (a) nor (b)
Q.11

An example of a periodic furnace is the

  • blast furnace stoves
  • blast furnace
  • coke oven heating chamber
  • rotary kilns
Q.12

In a muffle furnace, the muffle

  • retards the heat transfer.
  • assists in temperature equalisation in the charge.
  • permits the use of controlled atmosphere for the protection of stock.
  • all (a), (b) and (c).
Q.13

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

  • preheating the combustion air.
  • oxygen enrichment of combustion air.
  • preheating the fuel gas.
  • all (a), (b) & (c).
Q.14

Pulverised fuel fired furnaces employ __________ fuel firing.

  • horizontal
  • vertical
  • tangential
  • all (a), (b) and (c)
Q.15

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

  • 20
  • 40
  • 60
  • 80
Q.16

Ceramic recuperators compared to metallic recuperators for the same duty

  • are lighter.
  • occupy more space.
  • are less costly.
  • have higher pressure differential between flue gas & air side.
Q.17

Ostwald charts are meant for

  • computing the excess/deficiency of combustion air.
  • calculation of flue gas temperature.
  • computation of flue gas analysis.
  • none of these.
Q.18

Which is not a hearth furnace ?

  • Glass tank furnace
  • Open hearth furnace
  • Cupola
  • Reheating furnace
Q.19

An example of shaft furnace is the

  • L.D. converter
  • glass melting tank
  • blast furnace
  • soaking pit
Q.20

Which of the following is not a directly fired furnace ?

  • By-product coke oven
  • Calcination kiln
  • Sintering furnace
  • Open hearth furnace
Q.21

Maximum heat transfer in high temperature furnaces is by

  • conduction
  • convection
  • radiation
  • either (a), (b) or (c); depends on the type of furnace
Q.22

Cement Kiln is a

  • rotary Kiln
  • tunnel Kiln
  • natural draft furnace
  • batch furnace
Q.23

Dampers are located

  • before the I.D fan
  • after the I.D. fan
  • near the top of the chimney
  • anywhere after the I.D. fan
Q.24

In which of the waste heat recovery equipment, the flow of flue gas and air is alternately reversed after a fixed interval of time ?

  • Recuperator
  • Regenerator
  • Waste heat boiler
  • None of these
Q.25

Test specimen for determination of refractoriness under load (RUL) of a refractory is heated in a

  • furnace employing neutral atmosphere.
  • carbon resistance furnace.
  • reducing atmosphere.
  • furnace employing negative pressure.
Q.26

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

  • air is sucked in, so air leaks are more and hence the furnace efficiency is reduced.
  • the fan operates hot and hence blades are liable to corrosion and erosion.
  • positive pressure exists in the furnace.
  • none of these
Q.27

Regenerators are installed in

  • coke ovens
  • open hearth furnace
  • both (a) & (b)
  • neither (a) nor (b)
Q.28

Protective gas used in the annealing furnace for steel coil comprises of

  • 95% N2 + 5% H2
  • 5% H2 + 9% N2
  • 100% CO
  • 100 %H2
Q.29

An electric furnace producing heat by means of an electric arc struck between each of three electrodes and the charge is called __________ furnace.

  • resistance
  • arc
  • low frequency induction
  • none of these
Q.30

Turndown ratio of a burner gives an idea of the __________ in the furnace.

  • range of fuel firing rates
  • volume of the combustion chamber
  • maximum heat input rate only
  • minimum heat input rate only
0 h : 0 m : 1 s