Q.1

Air/gas ratio for complete combustion will be the highest for

  • LPG
  • gobar gas
  • coke oven gas
  • carburetted water gas
Q.2

Combustion of pulverised fuel

  • requires larger combustion chamber than rich gaseous fuel.
  • in a metallurgical furnace does not contaminate the product in the furnace by ash from fuel.
  • suppresses the discharge of fine dust and grit into atmosphere
  • all (a), (b) and (c)
Q.3

Steam is intermittently admitted into the fuel bed during the production of producer gas to

  • convert CO to CO2.
  • increase the combustion rate.
  • increase the gas production rate.
  • minimise the chances of clinker formation.
Q.4

Wood charcoal is obtained by the destructive distillation of wood. It is used in the production of activated carbon, which is not used for the

  • decolourisation of sugar.
  • solvent recovery from air and gases
  • absorption of gases and vapor.
  • electrode manufacture.
Q.5

'Wind loss' resulting from unscientific storage of coal may be the order of about __________ percent.

  • 2.5
  • 7.5
  • 10.5
  • 14.5
Q.6

Preheating of coal charge for the coke ovens reduces the

  • time of carbonisation.
  • yield of gas and tar.
  • fuel consumption in coking.
  • all (a), (b) and (c).
Q.7

Net calorific value is the gross calorific value less the __________ heat of water in the product of combustion when cooled to 15°C.

  • sensible
  • latent
  • sensible and latent
  • none of these
Q.8

The catalyst used in shift converter is

  • nickel
  • vanadium
  • silica gel
  • alumina
Q.9

Which of the following would require least amount of secondary air for combustion ?

  • Coke breeze containing 25% ash and 2% volatile matter.
  • Anthracite containing 10% volatile matter and 8% ash.
  • Bituminous coal containing 20% ash and 25% volatile matter.
  • Semi-bituminous coal containing 25% ash and 20% volatile matter.
Q.10

The maximum adiabatic flame temperature in air as compared to that in pure oxygen is

  • much lower.
  • much higher.
  • same.
  • either lower or higher, depends on the type of fuel.
Q.11

Which of the following is unsuitable fuel for producer gas manufacture ?

  • Coke.
  • Anthracite.
  • Coal having low fusion point of its ash.
  • Coal having high fusion point of its ash.
Q.12

Calorific value of coke oven gas is around __________ Kcal/Nm3.

  • 900
  • 4200
  • 7500
  • 2000
Q.13

Naphthalene is used for making

  • insecticides (e.g. moth balls).
  • unsaturated polyesters.
  • drug intermediates e.g. β-naphthol.
  • all (a), (b) and (c).
Q.14

A good coking coal should have high __________ content.

  • ash
  • sulphur & phosphorus
  • moisture
  • none of these
Q.15

In flue gas analysis by Orsat's apparatus, oxygen is absorbed by

  • potassium hydroxide.
  • cuprous chloride.
  • alkaline pyragllol solution.
  • none of these.
Q.16

Artificial draught produced by a fan can be controlled by the

  • speed of the fan.
  • damper.
  • variation in the pitch of the fan blades.
  • all (a), (b)and(c).
Q.17

Water gas constitutes mainly of

  • CO & H2
  • CO & N2
  • CO2 & H2
  • CH4 & H2
Q.18

Moisture loss is determined by the

  • humidity of combustion air.
  • moisture content of fuel.
  • both (a) and (b).
  • the water formed by combustion reaction.
Q.19

Beehive coke oven

  • facilitates by-products recovery.
  • takes 2-3 days for coking of coal but requires no external fuel for heating.
  • gives larger yield of coke (around 85%) as compared to by-product ovens.
  • produces coke with very poor strength.
Q.20

Turndown ratio of a gas burner is equal to the

  • maximum to minimum heat input ratio.
  • maximum to minimum permissible gas flow rate.
  • both (a) & (b).
  • minimum to maximum heat input ratio.
Q.21

Presence of force moisture in coal is most disadvantageous during its

  • transportation and handling
  • washing
  • pulverisation
  • storage
Q.22

Gasification of the solid fuel converts its organic part into combustible by interaction with air/oxygen and steam so as to obtain a secondary gaseous fuel of high calorific value having no ash. Gasification reactions are normally carried out at about __________ °C.

  • 400-500
  • 900-1000
  • 1400-1500
  • 1700-1800
Q.23

Low temperature oxidation of coal during storage does not decrease its

  • oxygen content
  • caking power
  • calorific value
  • none of these
Q.24

In general, the limit of inflammability/explosion limit of fuel gases is widened by the

  • increase in gas pressure.
  • increase in temperature (i.e. preheating).
  • use of pure oxygen for combustion instead of air.
  • all (a), (b) & (c).
Q.25

Which of the following is unsuitable fuel for producer gas manufacture ?

  • Coke.
  • Anthracite.
  • Coal having low fusion point of its ash.
  • Coal having high fusion point of its ash.
Q.26

Washing of coal is done to reduce the

  • inherent impurities
  • adhering impurities
  • mineral matter
  • both (b) and (c)
Q.27

Volatile matter content in coking coal may be about __________ percent.

  • 1
  • 7
  • 22
  • 46
Q.28

The main function of primary air in pulverised coal fired burner is to

  • burn CO to CO2.
  • dry and transport the coal.
  • have proper combustion by supplying it around the burner.
  • preheat the tertiary air used for complete combustion of CO to CO2.
Q.29

The optimum percentage of excess air for combustion depends upon the __________ of the fuel.

  • type (solid, liquid or gaseous)
  • calorific value
  • sulphur content
  • ignition temperature
Q.30

'Fat coals' are those coals which have very high

  • caking capacity.
  • volatile matter content.
  • fusion point of its ash.
  • inherent moisture content.
Q.31

Yield of charcoal in high temperature carbonisation of wood is about __________ percent.

  • 10
  • 25
  • 50
  • 75
Q.32

A good metallurgical coke

  • should have high porosity.
  • should be brittle.
  • must contain moderate quantities of ash, moisture, sulphur and volatile matters.
  • should have low fusion point of its ash.
Q.33

Highly caking coals

  • produce weak coke.
  • produce strong coke.
  • may damage the coke oven walls during carbonisation.
  • both (b) and (c).
Q.34

The advantage of firing pulverised coal in the furnace lies in the fact, that it

  • permits the use of high ash content coal.
  • permits the use of low fusion point ash coal.
  • accelerates the burning rate and economises on fuel combustion.
  • all (a), (b) and (c).
Q.35

A coal having higher volatile matter content, has lower

  • smoking tendency on burning.
  • coke oven gas yield on carbonisation.
  • chance of catching fire during storage in open space.
  • ignition temperature.
Q.36

Pick out the wrong statement.

  • Cokes of high reactivity are obtained from weakly coking coals.
  • Cokes of high reactivity are obtained from strongly coking coals.
  • Reactivity of coke is inversely proportional to its absolute density.
  • Abrasion index of the coke is a measure of its hardness.
Q.37

Coals used for the generation of producer gas should have

  • high caking index.
  • low fusion point of ash.
  • high volatile matter content.
  • very low ash content (8-10%).
Q.38

Natural draft created by the chimney depends upon

  • temperature of the flue gas.
  • its height.
  • both (a) & (b).
  • neither (a) nor (b).
Q.39

Oxygen required for theoretically complete combustion of 1 Nm3 methane is __________ Nm3.

  • 2
  • 4
  • 6
  • 1
Q.40

Coke made in narrower by-product coke ovens (as compared to wider ovens) is

  • less reactive
  • stronger
  • smaller in size
  • all (a), (b) & (c)
Q.41

Purity of coke means that, it is high in carbon and low in

  • volatiles
  • ash
  • iron
  • moisture
Q.42

Tar is a better fuel than furnace oil, because of its

  • higher calorific value.
  • lower sulphur content.
  • higher emissivity (0.8 - 0.9) resulting in higher radiation heat transfer rate.
  • both (a) and (b).
Q.43

With increase in the oxygen content of the coal, its __________ decreases.

  • calorific value
  • caking power
  • both (a) & (b)
  • neither (a) nor (b)
Q.44

Caking coal is desirable for

  • burning on travelling grate.
  • coke making.
  • burning on firebars.
  • all (a), (b) and (c).
Q.45

Volumetric ratio of N2 to O2 in dry atmospheric air is

  • 0.21
  • 3.76
  • 4.76
  • 0.79
Q.46

__________ is used as jet engine fuel.

  • Petrol
  • Diesel
  • Kerosene
  • LPG
Q.47

Fuel for a nuclear reactor (thermal) is

  • uranium
  • plutonium
  • radium
  • none of these
Q.48

Highly reactive coke have lower

  • porosity.
  • coke reactivity index (CRI).
  • Critical air blast (CAB) value.
  • both (b) and (c).
Q.49

A coal with high ash content

  • has higher calorific value.
  • is harder and stronger.
  • is not subjected to washing.
  • has low quantity of mineral matter.
Q.50

The main advantage of forced draft over natural draft is that

  • combustion of fuel is complete.
  • smaller height chimney can be used.
  • furnace control is easier.
  • all (a), (b) & (c).
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