Q.1

Regenerators compared to the recuperators for the same duty

  • occupy more space
  • are less costly
  • are of smaller size
  • all (a), (b) and (c)
Q.2

The method of Lobo and Evans is concerned with the calculation of the

  • heat absorption in radiant section of a furnace.
  • heat transfer by forced convection in a reboiler.
  • heat transfer in vacuum condensers.
  • mass transfer co-efficient.
Q.3

Regenerators are normally provided in the

  • glass melting furnace.
  • open hearth furnace.
  • by product coke ovens.
  • all (a), (b) and (c).
Q.4

Thermal efficiency of furnaces can be improved by

  • waste heat recovery from flue gas.
  • minimising heat losses from furnace walls.
  • maintaining proper draught.
  • all (a), (b) and (c).
Q.5

The main function of a muffle in the muffle furnace is to

  • protect the charge from the effects of the products of combustion.
  • smooth out temperature inequalities on the combustion side of the muffle wall.
  • both (a) & (b)
  • neither (a) nor (b)
Q.6

Which of the following is a heat treatment furnace ?

  • Muffle furnace
  • Annealing furnace
  • Reheating furnace
  • Rotary kiln
Q.7

Out of the following fuels used in a furnace exhausting flue gas at a temperature of 600°C, the percentage stack loss will be maximum in case of complete combustion of

  • furnace oil with air.
  • furnace oil with oxygen.
  • blast furnace gas with air.
  • blast furnace gas with oxygen.
Q.8

In low or standard frequency induction furnace, heat is produced by the

  • combination of induced current and skin effect.
  • induction and resistance.
  • current flow through a heating element.
  • none of these.
Q.9

Which furnace employs natural draft ?

  • Coke oven
  • Boiler
  • Rotary kilns
  • L.D. converter
Q.10

The heating capacity of muffle furnace depends on the

  • surface area & emissivity of the stock.
  • properties of the muffle wall (temperature, area, emissivity).
  • both (a) & (b)
  • neither (a) nor (b)
Q.11

Forced recirculation of furnace gases is practised

  • to increase heat transfer by convection.
  • to ensure uniform temperature.
  • in furnaces, operating below 750°C.
  • all (a), (b) and (c).
Q.12

Regenerators are used for waste heat recovery in

  • by-product coke ovens
  • beehive coke oven
  • blast furnace stoves
  • soaking pits
Q.13

Reverberatory furnace is used for

  • roasting/reduction of ores
  • annealing steel coil
  • heating air
  • steel melting
Q.14

Metallic recuperators are not used for waste heat recovery, if the hot flue gas temperature is above __________ °C, because corrosion prevails at higher temperatures.

  • 350
  • 750
  • 1050
  • 1250
Q.15

Shaft furnaces are used for

  • smelting
  • calcining
  • roasting
  • all (a), (b) and (c)
Q.16

Flue gas outlet temperature from the chimney of any furnace should be ideally about __________ °C.

  • 50
  • 100
  • 150
  • 250
Q.17

Very high pressure boilers are usually __________ boilers.

  • fire tube
  • water tube
  • waste heat
  • natural circulation
Q.18

__________ atmosphere is maintained inside an iron blast furnace.

  • Oxidising
  • Reducing
  • Inert
  • Decarburising
Q.19

Scaling of furnace stock is reduced by __________ in flue gas.

  • CO
  • H2
  • high CO/CO2
  • all (a), (b) & (c)
Q.20

Which of the following is a batch furnace ?

  • Cupola
  • Reheating furnace
  • Glass tank furnace
  • None of these
Q.21

Design of waste heat boiler for recovery of waste heat from furnace gases depends upon the

  • quantity & temperature of waste gas.
  • dust concentration & nature of dust in waste gas.
  • corrosive nature of the waste gas.
  • all (a), (b) and (c).
Q.22

Which of the following furnaces will have maximum thermal efficiency ?

  • Soaking pits
  • Walking beam reheating furnace
  • Boiler furnace
  • Rotary kilns
Q.23

Overall thermal efficiency of a lumpy coal fired suitably designed heating furnace, if operated & maintained properly may be about __________ percent.

  • 10-15
  • 25-30
  • 45-50
  • 65-70
Q.24

Furnace pressure is normally controlled by regulating the

  • air pressure
  • fuel gas pressure
  • speed of I.D. fan
  • damper
Q.25

Hearth furnaces are not used for

  • roasting
  • melting
  • reheating
  • none of these
Q.26

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

  • type of fuels viz solid, liquid or gaseous.
  • flue gas temperature.
  • emissivity of refractory walls.
  • initial temperature of the charged stock.
Q.27

__________ furnace is not an electric furnace.

  • Arc
  • Induction
  • Pot
  • Resistance.
Q.28

In a heating process, a heat flow diagram in which the quantities of heat in the various items of a heat balance are represented by the width of a band is called the

  • Ostwald chart
  • Cox chart
  • Sankey diagram
  • none of these
Q.29

Air filtration in a furnace

  • reduces its thermal efficiency.
  • is indicated by flame sting out.
  • increases the flue gas temperature.
  • none of these.
Q.30

Which of the following is the most important deterrants to an extended use of pulverised coal in boiler firing ?

  • Ash disposal problem.
  • Excessive fly ash discharge from the stack.
  • Higher power consumption in its transportation.
  • Erosion of induced draft fan blades.
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