Fuels and Combustion Quiz 6

1 / 50

Naphthalene recovered from coke oven gas is used_____?

For making electrodes

As moth balls (insecticides)

As a fuel in furnaces

As moisture proof coating on fibres

2 / 50

Number of macrocomponents present in coal according to Stopes are _____?

Five

Two

Four

Six

3 / 50

Producer gas containing least amount of tar is produced by the__________?

Partial combustion of coal

Atmospheric pressure gasification of coal (e.g., in Kopper-Totzek gasifier)

High pressure gasification of coal (e.g. in Lurgi gasifier)

Partial combustion of large size (< 50 mm) coke

4 / 50

Pick out the wrong statement ?

Coal based fertiliser plants in India at Talcher (Orissa) and Ramagundam (A.P) employ Kopper-Totzek process of coal gasification

The calorific value (kcal/Nm3) of coke oven gas reduces on removal of hydrogen from it by cryogenic method

Ash is normally removed as ?fly-ash? in Kopper-Totzek process of coal gasification

Percentage of ash in coke produced from medium coking coal is more than that in coal

5 / 50

Percentage of carbon monoxide in blast furnace gas may be around ______ ?

6 / 50

Presence of force moisture in coal is most disadvantageous during its ___________?

Washing

Pulverisation

Storage

Transportation and handling

7 / 50

Out of the following fuels, the difference between the net and gross calorific value is maximum in case of__________?

Blast furnace gas

Bituminous coal

Pitch

Fuel oil

8 / 50

Pick out the correct statement ?

With increase in oxygen content, moisture holding capacity of coal increases and the caking power decreases

All A., B. and C.

Oxygen content decreases from lignite to bituminous coal as the coalification increases

The less the oxygen content, better is the coal, as it reduces the calorific value

9 / 50

Orsat apparatus is meant for _____?

Gravimetric analysis of flue gas

Direct determination of nitrogen in flue gas by absorbing it in ammoniacal cuprous chloride

None of these

Finding out combustion efficiency

10 / 50

Pick out the wrong statement ?

Gaseous fuels require the least % excess air for complete combustion

The ratio of fixed carbon to volatile matter percentage in coal is called its ?fuel ratio?

Calorific value of natural gas is more than that of LPG

High concentration of oxygen in flue gas means high stack loss

11 / 50

Pick out the wrong statement ?

The minimum temperature, at which a petroleum oil vapor catches fire and continues to burn, is called its flash point

Each ton of petroleum oil on distillation produces about 30-50 Nm3 of gas

LPG is also used as fuel for automobiles & small furnaces and for cutting & welding of metals

Maximum yield of naphthalene is obtained on distillation of crude oil

12 / 50

Pick the odd man out?

Oil gas

Briquettes

Wood

Pitch creosote mixture

13 / 50

Presence of nitrogen in combustion air does not reduce the ______?

Flame temperature

Any of the above

Flue gas temperature

Amount of heat liberated

14 / 50

Orsat apparatus___________?

Determines N2 in flue gas indirectly

All A., B. & C.

Gives flue gas analysis on dry basis

Can?t determine CO in flue gas, if it is < 0.2%

15 / 50

Naphthalene is used for making__________?

All A., B. and C.

Drug intermediates e.g. ?-naphthol

Insecticides (e.g. moth balls)

Unsaturated polyesters

16 / 50

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

None of these

Sensible and latent

17 / 50

Nitrogen present in the flue gas is determined in the Orsat apparatus by absorbing it in_______?

Pyrogallol solution

Ammoniacal cuprous chloride

None of these

KOH

18 / 50

Natural draft created by the chimney depends upon _______?

Both A. & B.

Neither A. nor B.

Temperature of the flue gas

Its height

19 / 50

Prime coking coal is always blended with medium or non- coking coal before carbonisation___________?

Neither A. nor B.

Because, it alone produces unreactive coke

Both A. and B.

To check against its excessive swelling during heating, which may exert high pressure and damage coke oven walls

20 / 50

Of the total tar present in raw coke oven gas, the tar recovered in primary cooler is about ________ percent?

21 / 50

Presence of free moisture in coal is most disadvantageous during__________?

None of these

Combustion of fire slacks on the grates

Handling (e.g. when emptying wagons)

Its pulverisation (as it requires more power)

22 / 50

Preheating of combustion air is done to _____?

Reduce its requirement for effecting the complete combustion

Increase the calorific value of the fuel

Increase the adiabatic flame temperature

Complete the combustion of fuel

23 / 50

Preheating of _______ the flame temperature?

Either the fuel or the air does not affect

Either the fuel or the air or both, increases

The gaseous fuel before combustion decreases

Combustion air decreases

24 / 50

Presence of free moisture in coal during its high temperature carbonisation _______?

Increases the loss of fine coal dust from the ovens when charging

Protects the volatile products from pyrolysis (cracking) in the presence of hot coke and hot oven walls

None of these

Reduces the coking time

25 / 50

Pick out the wrong statement ?

Specific heat of coal decreases with increases in the volatile matter and decrease in the C/H ratio of coal

Refractive index and reflectance of coal increases with the increasing rank of coal

Angle of repose of coal increases with its increasing size

Specific gravity of coal increases with its increasing maturity

26 / 50

Nitrogen in coal__________?

Is present upto 1-2%

All A., B. and C.

Is recovered as ammonia during its carbonisation

Comes from protein in parent vegetable matter

27 / 50

Narrow coke ovens as compared to wider coke ovens__________?

Produce smaller coke

Require less time of carbonisation

Produce stronger coke

All A., B. and C.

28 / 50

Oxygen required for theoretically complete combustion of 1 Nm3 methane is _______ Nm3?

29 / 50

Natural draught produced by a chimney depends upon the _______?

Both A. and B.

Height of the chimney

Density of the chimney gases

Neither A. nor B.

30 / 50

One kg of carbon for theoretically complete combustion requires _______ kg of air?

0.5

11.5

31 / 50

Pensky-Marten apparatus is used for those oils, whose flash points are ______ ?F?

< 90

< 120

90-110

> 120

32 / 50

Pick out the wrong statement ?

Pulverised fuel can be completely burnt with less percentage of excess air compared to lump coal

None of these

Low grade coal can be used, but generally high volatile matter coals are more suitable for making pulverised fuel

Regulation of furnace temperature and atmosphere (oxidising or reducing) is easily possible with pulverised fuel firing

33 / 50

Out of the following, which is the most important parameter for the blast furnace grade coke ?

Volatile matter content

CSR & CRI

Ash content

Moisture content

34 / 50

Power alcohol as compared to straight run gasoline has lower _________?

Specific gravity

Viscosity

Octane number

Calorific value

35 / 50

Producer gas comprises mainly of _________?

CO2 & H2

CO & N2

CO & H2

CO2 & N2

36 / 50

Percentage of hydrogen in coke oven gas may be around _____?

37 / 50

Percentage of nitrogen in blast furnace gas may be around___________?

38 / 50

Percentage of methane in coke oven gas may be around _______?

39 / 50

Pick out the wrong statement ?

Carbonisation time in a by-product coke oven is about 16 hours

Gross and net calorific value of a fuel is the same, if it does not contain hydrogen or hydrocarbons

Carburetted water gas is also called blue gas

Coals are divided in four species according to their carbon content in Seylor?s classification

40 / 50

Preheating of coal charge for the coke ovens reduces the ___________?

Fuel consumption in coking

All A., B. and C.

Yield of gas and tar

Time of carbonisation

41 / 50

Pitch creosote mixture (PCM) as compared to furnace oil is a better fuel, because its _____?

Sulphur content is lower

All A., B. and C.

Emissivity factor is higher

Flue gas has lower dew point thereby facilitating more waste heat recovery

42 / 50

Presence of phosphorous in metallurgical coal___________?

Is not undesirable

Badly affects the quality of steel

Reduces its calorific value

Increases its caking power

43 / 50

Oxygen percentage (by weight) in atmospheric air is__________?

44 / 50

Octane number of 2, 2, 4 ? trimethyl pentane is ___________?

100

More than 100

In between 0 and 100

45 / 50

Out of the following fuels, the difference between gross and net calorific value will be minimum in case of_____?

Natural gas

Blast furnace gas

Water gas

Coke oven gas

46 / 50

Presence of _______ in a dry gaseous fuel does not contribute to its calorific value?

Sulphur

Carbon

Oxygen

Hydrogen

47 / 50

Oxygen content in a flue gas was found to be 4%. It implies that excess air used for combustion was around _______ percent?

48 / 50

Preheating of a gaseous fuel results in increased______?

Flame length

Flame temperature

Quantity of flue gas

Ignition temperature

49 / 50

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

Abrasion index of the coke is a measure of its hardness

Reactivity of coke is inversely proportional to its absolute density

50 / 50

Pick out the wrong statement ?

Burning the fuel with excess pure oxygen results in maximum theoretical flame temperature

Theoretical flame temperature is the temperature attained by the products of combustion, when the fuel is burned without loss or gain of heat

Burning the fuel with theoretically required amount of pure oxygen results in attainment of maximum adiabatic flame temperature

Adiabatic flame temperatures of actual combustions are always less than the maximum values

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