Fuels and Combustion Quiz 1

1 / 50

A certain thickness of the coal, if stored unscientifically on soft (katcha) ground having no metallic/concrete flooring gets sunked into the ground, which is termed as the ?carpet loss?. The carpet loss may be of the order of _______ cms?

1 to 2

20 to 40

3 to 4

5 to 15

2 / 50

A coal gasifier operating at 20 atm. (e.g. Lurgi gasifier) as compared to one operating at atmospheric pressure (e.g. Kopper-Totzek or Winkler gasifier) will produce a gas having _______?

None of these

Lower carbon dioxide content

Higher methane content and thus higher calorific value

Higher carbon monoxide content

3 / 50

A coal containing high amount of volatile matter will have___________?

Low adiabatic flame temperature

Very little ash content

High fusion point of its ash

Low ignition temperature

4 / 50

?Wind loss? resulting from unscientific storage of coal may be the order of about ______ percent?

10.5

2.5

7.5

14.5

5 / 50

A particular coal is said to be free burning when it ___________?

None of these

Gives smokeless burning

Burns completely

Shows little or no fusing action

6 / 50

A coal that softens and fuses on heating is__________?

Classified

Non-caking

Caking

Carbonised

7 / 50

?Fat coals? are those coals which have very high______?

Caking capacity

Volatile matter content

Inherent moisture content

Fusion point of its ash

8 / 50

Ammonia content in raw coke oven gas is about ______ gm/Nm3?

100

9 / 50

A coal with high ash content is undesirable, as_________?

It is abrasive to the coal pulveriser (i.e. ball mill) and the combustion chamber

The ash retains the sulphur & phosphorus and thus affects the quality of products in metallurgical furnace apart from increasing the slag volume. Besides, it may fuse and stick to the boiler tubes thereby reducing the heat transfer

The ash in molten condition gets absorbed in the pores of the refractory lining of the furnace and causes its spalling due to different co-efficient of expansion/contraction of the refractory and the ash

All A., B. and C.

10 / 50

A coal having high amount of volatile matter______?

Ignites easily and burns with long smoky flame

Would require smaller combustion chamber

All A., B. and C.

Produces very little of tar and gas on carbonisation

11 / 50

A coal with high ash content_____?

Has low quantity of mineral matter

Is harder and stronger

Is not subjected to washing

Has higher calorific value

12 / 50

?Fuel? can be defined as a substance which produces heat by_____?

Combustion

Nuclear fission

All A., B. & C.

Nuclear fusion

13 / 50

______ present in coal is not determined in its ultimate analysis ?

Nitrogen

Hydrogen

Total carbon

Fixed carbon

14 / 50

______ of the coal is the basis for Seylor?s coal classification?

Calorific value

Proximate analysis

Caking index

Ultimate analysis

15 / 50

Actual flame temperature is always lower than the adiabatic flame temperature, because there is_________?

Neither A. nor B.

Both A. and B.

Always loss of heat from the flame

No possibility of obtaining complete combustion at high temperature

16 / 50

A travelling grate stoker is meant for the efficient burning of _______ coal?

Non-caking

High ash

Caking

Pulverised

17 / 50

__________ is used as jet engine fuel ?

Diesel

Kerosene

LPG

Petrol

18 / 50

A coal with high ______ content, would ignite most easily?

Fixed carbon

Ash

Volatile matter

Oxygen

19 / 50

Anthracite can be used for_____?

Making carbon electrodes

All A., B. and C.

Recarbonising steel

Blending with highly coking coal to check its swelling which helps in saving coke even walls from damage and to produce high strength coke

20 / 50

Adiabatic flame temperature of a fuel is dependent on the initial temperature of_____?

Fuel

Both A. & B.

Air

Neither A. nor B.

21 / 50

?Micum Index? of a coke is a measure of its_____?

Hardness & strength

Porosity

Bulk density

Reactivity

22 / 50

A good coking coal should have high _______ content?

Moisture

Ash

Sulphur & phosphorus

None of these

23 / 50

About ______ Nm3 of air will be required for the complete combustion of 2Nm3 of CO?

24 / 50

A liquid/gaseous fuel containing hydrocarbons and high amount of sulphur is burnt with 40% excess air. The flue gas still contains large amount of carbon monoxide. This may be due to the__________?

Presence of large quantity of hydrogen in the fuel

High sulphur content in the fuel

Low calorific value of the fuel

Lack of thorough mixing of fuel with air

25 / 50

64-132) rank coal (ASTM) means a coal with 64%_____?

Ash and heating value around 13, 200 BTU/1b

None of these

Fixed carbon and having a heating value around 13, 200 BTU/1b

Fixed carbon and heating value around 132 BTU/1b

26 / 50

A carbonaceous fuel (containing no H2 or hydrocarbons) is burnt and the resulting flue gas contains 21% CO2. It means that_____?

21% excess air has been used for combustion

21% excess oxygen has been used for combustion

No excess air has been used for combustion

Complete combustion of fuel has taken place

27 / 50

Abel apparatus is used for those oils, whose flash points are ___________?F?

< 120

> 120

> 280

300-600

28 / 50

A fuel with high heat release rate will__________?

Have high adiabatic flame temperature

Require smaller combustion chamber

None of these

Have high calorific value

29 / 50

A good metallurgical coke_____?

Should have high porosity

Should have low fusion point of its ash

Should be brittle

Must contain moderate quantities of ash, moisture, sulphur and volatile matters

30 / 50

?Overfire burning? in a furnace is a phenomenon characterised by the ___________?

Burning of carbon monoxide and other incombustibles in upper zone of furnace by supplying more air

None of these

Supply of excess air

Supply of excess fuel

31 / 50

Artificial draught produced by a fan can be controlled by the_____?

Damper

Variation in the pitch of the fan blades

All A., B. and C.

Speed of the fan

32 / 50

Anthracite coal ______?

Burns with short, bluish, yellow-tipped flame producing very little smoke

Ignites more easily than bituminous coal

Is essentially a coking coal

Contains more volatile matter than bituminous coal

33 / 50

?Fat? coal means a coal having _____?

Low calorific value

Low ash content

High volatile matter

Non smoking tendency

34 / 50

A sample of natural gas containing 80% methane (CH4) and rest nitrogen (N2) is burnt with 20% excess air. With 80% of the combustibles producing CO2 and the remainder going to CO, the Orsat analysis in volume percent is__________?

CO2 : 7.42, CO : 1.86, O2 : 4.64, N2:86.02

CO2 : 6.26, CO : 1.56, O2 : 3.91, H2O :15.66, N2 : 72.60

CO2 : 7.60, CO : 1.90, O2 : 4.75, N2 : 85.74

CO2 : 6.39, CO : 1.60, O2 : 3.99, H2O:25.96, N2:72.06

35 / 50

A good quality coal should have _____?

High sulphur

None of these

Low fusion point of ash

High ash content

36 / 50

______ prohibits the use of alcohols directly in petrol engines ?

High cost & availability

Low calorific value

Low octane number

Low flash point

37 / 50

A fuel containing carbon and carbon monoxide (but containing no hydrogen or its compounds) is burnt in pure oxygen at constant pressure. Its gross calorific value as compared to net calorific value will be__________?

Less

Same

Data insufficient; can?t be predicted

38 / 50

A coal having high ratio of volatile matter to fixed carbon as compared to a coal having low ratio of volatile matter to fixed carbon __________?

Is more difficult to ignite and produces a shorter flame

None of these

Is less liable to spontaneous combustion on storage

Requires smaller combustion space and less secondary air

39 / 50

A coal having higher volatile matter content will necessarily have lower______?

Ash fusion temperature

Calorific value

Ignition temperature

Caking index

40 / 50

Abrasion index of blast furnace coke should be around ______ percent?

41 / 50

A coal containing very high percentage of durain is called _______ coal?

Non-banded

Splint

Bright

Boghead

42 / 50

Advantages of fluidised bed combustion are ______?

Lower furnace operating temperature

All A., B. & C.

Reduced NOx formation in flue gas

High heat transfer rate

43 / 50

(64-132) rank coal (ASTM) means a coal with 64%_____?

Fixed carbon and having a heat value of 13, 200 BTU/1b

None of these

Fixed carbon and a heating value of 132 BTU/1b

Ash and a heating value of 13, 200 BTU/1b

44 / 50

A coal having higher volatile matter content, has lower__________?

Chance of catching fire during storage in open space

Ignition temperature

Coke oven gas yield on carbonisation

Smoking tendency on burning

45 / 50

______ has the widest inflammability limit (explosion limit) of all the gases?

Carbon monoxide

Hydrogen

Methane

Acetylene

46 / 50

?Wobbe index? is a characteristic of___________?

Gaseous fuels

Fat coals

Solid fuels

Liquid fuels

47 / 50

A coal having high volatile matter content will _________?

None of these

Have a very high calorific value

Burn with a small non-smoky flame

Give less yield of tar and gas on carbonisation

48 / 50

A gaseous fuel in order to develop luminosity on burning, must contain ___________?

Hydrocarbons

Oxygen

Carbon monoxide

Hydrogen

49 / 50

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

Coke oven gas

Carburetted water gas

LPG

Gobar gas

50 / 50

_____ process is meant for direct hydrogenation of coal to produce liquid fuel?

Lurgi

Bergius

Fischer-Tropsch

None of these

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