Fuels and Combustion Quiz 1

1 / 50

Anthracite coal ______?

Ignites more easily than bituminous coal

Contains more volatile matter than bituminous coal

Is essentially a coking coal

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

2 / 50

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

Pulverised

Caking

Non-caking

High ash

3 / 50

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

All A., B. & C.

Nuclear fission

Combustion

Nuclear fusion

4 / 50

A coal that softens and fuses on heating is__________?

Carbonised

Caking

Classified

Non-caking

5 / 50

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

10.5

7.5

2.5

14.5

6 / 50

______ prohibits the use of alcohols directly in petrol engines ?

Low calorific value

Low octane number

Low flash point

High cost & availability

7 / 50

A good quality coal should have _____?

Low fusion point of ash

High sulphur

None of these

High ash content

8 / 50

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

21% excess oxygen has been used for combustion

21% excess air has been used for combustion

Complete combustion of fuel has taken place

No excess air has been used for combustion

9 / 50

A coal having higher volatile matter content, has lower__________?

Ignition temperature

Chance of catching fire during storage in open space

Coke oven gas yield on carbonisation

Smoking tendency on burning

10 / 50

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

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

None of these

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

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

11 / 50

__________ is used as jet engine fuel ?

LPG

Petrol

Diesel

Kerosene

12 / 50

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

Supply of excess air

None of these

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

Supply of excess fuel

13 / 50

?Wobbe index? is a characteristic of___________?

Solid fuels

Fat coals

Liquid fuels

Gaseous fuels

14 / 50

A coal containing high amount of volatile matter will have___________?

Low ignition temperature

Low adiabatic flame temperature

Very little ash content

High fusion point of its ash

15 / 50

A fuel with high heat release rate will__________?

Have high adiabatic flame temperature

Have high calorific value

Require smaller combustion chamber

None of these

16 / 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

17 / 50

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

Bright

Non-banded

Boghead

Splint

18 / 50

Anthracite can be used for_____?

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

Recarbonising steel

Making carbon electrodes

All A., B. and C.

19 / 50

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

Fixed carbon

Nitrogen

Total carbon

Hydrogen

20 / 50

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

Always loss of heat from the flame

No possibility of obtaining complete combustion at high temperature

Neither A. nor B.

Both A. and B.

21 / 50

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

Hydrocarbons

Oxygen

Carbon monoxide

Hydrogen

22 / 50

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

23 / 50

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

Coke oven gas

Carburetted water gas

LPG

Gobar gas

24 / 50

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

Fixed carbon and heating value around 132 BTU/1b

None of these

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

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

25 / 50

A coal having high volatile matter content will _________?

None of these

Burn with a small non-smoky flame

Give less yield of tar and gas on carbonisation

Have a very high calorific value

26 / 50

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

100

27 / 50

A coal with high ash content_____?

Has low quantity of mineral matter

Is harder and stronger

Has higher calorific value

Is not subjected to washing

28 / 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 __________?

Requires smaller combustion space and less secondary air

Is more difficult to ignite and produces a shorter flame

Is less liable to spontaneous combustion on storage

None of these

29 / 50

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

Methane

Carbon monoxide

Hydrogen

Acetylene

30 / 50

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

Volatile matter content

Fusion point of its ash

Caking capacity

Inherent moisture content

31 / 50

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

32 / 50

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

Burns completely

Gives smokeless burning

Shows little or no fusing action

None of these

33 / 50

A good coking coal should have high _______ content?

Ash

Sulphur & phosphorus

None of these

Moisture

34 / 50

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

Speed of the fan

All A., B. and C.

Damper

Variation in the pitch of the fan blades

35 / 50

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

Both A. & B.

Fuel

Air

Neither A. nor B.

36 / 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__________?

Same

Less

Data insufficient; can?t be predicted

37 / 50

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

< 120

> 280

300-600

> 120

38 / 50

A good metallurgical coke_____?

Should have high porosity

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

Should have low fusion point of its ash

Should be brittle

39 / 50

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

Bulk density

Reactivity

Porosity

Hardness & strength

40 / 50

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

Fischer-Tropsch

Lurgi

Bergius

None of these

41 / 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__________?

Low calorific value of the fuel

Lack of thorough mixing of fuel with air

Presence of large quantity of hydrogen in the fuel

High sulphur content in the fuel

42 / 50

A coal having high amount of volatile matter______?

All A., B. and C.

Ignites easily and burns with long smoky flame

Would require smaller combustion chamber

Produces very little of tar and gas on carbonisation

43 / 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 : 7.60, CO : 1.90, O2 : 4.75, N2 : 85.74

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

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

44 / 50

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

Calorific value

Ignition temperature

Ash fusion temperature

Caking index

45 / 50

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

Calorific value

Caking index

Proximate analysis

Ultimate analysis

46 / 50

A coal with high ash content is undesirable, as_________?

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

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

All A., B. and C.

47 / 50

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

Oxygen

Ash

Volatile matter

Fixed carbon

48 / 50

?Fat? coal means a coal having _____?

High volatile matter

Non smoking tendency

Low calorific value

Low ash content

49 / 50

Advantages of fluidised bed combustion are ______?

All A., B. & C.

Lower furnace operating temperature

Reduced NOx formation in flue gas

High heat transfer rate

50 / 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?

3 to 4

5 to 15

20 to 40

1 to 2

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