Q.1
The advantages of firing pulverised coal in the furnace lies in the fact that, it
Q.2
Low stack loss indicates the
Q.3
The rate of scaling of furnace stock depends upon the
Q.4
Which of the following is the most suitable for preheating combustion air above 650°C ?
Q.5
Which of the following is a natural draft furnace?
Q.6

An improved and fuel efficient version of the pusher type reheating furnace is the __________ furnace.

  • walking beam
  • shaft
  • tunnel
  • rotary hearth
Q.7

Which of the following variables affects the furnace capacity ?

  • Temperature of flue gas.
  • Thermal conductivity of stock.
  • Thickness of heating stock.
  • All (a), (b) and (c).
Q.8

In a furnace, the heat taken by the charge/stock and the heat lost to the furnace structure & flue gases depends on the

  • rate of firing and emissivity of flame.
  • thermal conductivity of the charge & structural materials of furnace.
  • nature of process ; whether batch, continuous or intermittant.
  • all (a), (b) and (c)
Q.9

In which of the following furnaces, the gases are sucked through the stock bed from below?

  • Soaking pit
  • Sintering machine
  • Beehive oven
  • None of these
Q.10

Waste heat from the outgoing flue gases in a thermal power plant is recovered by a/an

  • economiser
  • steam superheater
  • air preheater
  • all (a), (b) and (c)
Q.11

Recuperator is

  • not used for fuel gas preheating.
  • an intermittant waste heat recovery equipment.
  • a continuous waste heat recovery equipment.
  • heavier than regenerator meant for the same duty.
Q.12

Which is not accomplished in an underfired furnace ?

  • Increase in heating capacity/m2 of floor space.
  • Elimination of cold spot at the bottom of the charge.
  • Reduction in the temperature of furnace gases.
  • Portection of the periphery of the charge from excessive radiation.
Q.13

Which of the following is not a recuperative furnace ?

  • Soaking pit
  • Reheating furnace
  • Steamboiler
  • Coke oven.
Q.14

Fuel economy in an industrial furnace operation can not be achieved by the use of

  • stoichiometric combustion air.
  • non-preheated combustion air.
  • combustion air not enriched with oxygen.
  • recupterators.
Q.15

Artificial draught produced by a fan in the furnace can be controlled by the

  • speed of the fan.
  • damper.
  • variation in the pitch of fan blades.
  • all (a), (b) and (c).
Q.16

The resistance furnace produces heat by the

  • electric arc struck between electrodes and the charge.
  • flow of current through a heating element.
  • combination of induced current and skin effect.
  • none of these
Q.17

In practical operation of any furnace, zero oxygen percentage or theoretical CO2 percentage in flue gas is rarely achieved, because of

  • use of non-preheated combustion air.
  • use of pulverised solid fuels.
  • imperfect mixing of fuel & air and infiltration of air.
  • use of excessive positive draft in the furnace.
Q.18

Size of the combustion chamber of a furnace depends upon the

  • heat release rate of the fuel.
  • preheat temperature of fuel & air.
  • method of mixing the fuel & air.
  • all (a), (b) and (c).
Q.19

Pick out the wrong statement.

  • Addition of methane to the furnace atmosphere reduces decarburising by hydrogen.
  • Nitrogen in presence of steam decar-burises high carbon steel, whereas hydrocarbon gases carburise the surface of steel at annealing temperatures.
  • Active nitrogen (formed by cracking ammonia at the metal surface) cause nitride formation with increase in surface hardness.
  • none of these.
Q.20

The function of an economiser in a boiler is to preheat the

  • feedwater
  • combustion air
  • pulverised coal
  • furnace oil
Q.21

Regenerators as compared to recuperators for the same duty

  • store smaller quantity of waste heat
  • are lighter & compact
  • involve higher initial cost
  • all (a), (b) & (c)
Q.22

Blast furnace stoves are meant for heating

  • none of these
  • air
  • blast furnace gas
  • steam
Q.23

Pot furnace which is either regenerative or recupterative, is used in the manufacture of

  • glass
  • stainless steel
  • potteries
  • refractory bricks.
Q.24

Which of the following variables does not affect the furnace capacity ?

  • Size of the furnace.
  • Gas velocity in furnace.
  • Ratio of wall surface to surface of stock.
  • None of these.
Q.25

In salt bath furnace, heat is transferred to the charge mainly by

  • conduction
  • convection
  • radiation
  • none of these
Q.26

While the fuel fired furnace can be used upto a maximum temperature of about 1700°C, the electric furnace can be used upto a temperature of about __________ °C.

  • 2000
  • 3000
  • 4500
  • 6000
Q.27

Rate of heat release in a furnace, which is the measure of heat intensity is defined as

  • kcal/hr/m3 combustion space.
  • kcal/m3 combustion space.
  • kcal/hr.
  • none of these.
Q.28

Reheating furnace (pusher type) is used for heating

  • ingots
  • slabs
  • steel coils
  • steel sheets
Q.29

Which one is not an induced draught furnace?

  • Blast furnace stove
  • Sintering furnace
  • High pressure boiler
  • None of these
Q.30

Which furnace employs an I.D. fan for the removal of flue gases from the furnace ?

  • Coke oven.
  • Blast furnace stoves.
  • Beehive coke oven.
  • High pressure boiler.
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