Fuels and Combustion Quiz 1

1 / 50

A coal containing high amount of volatile matter will have___________?

High fusion point of its ash

Low adiabatic flame temperature

Low ignition temperature

Very little ash content

2 / 50

A coal having higher volatile matter content, has lower__________?

Smoking tendency on burning

Coke oven gas yield on carbonisation

Ignition temperature

Chance of catching fire during storage in open space

3 / 50

?Fat? coal means a coal having _____?

Low calorific value

High volatile matter

Low ash content

Non smoking tendency

4 / 50

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

Hydrocarbons

Oxygen

Hydrogen

Carbon monoxide

5 / 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 less liable to spontaneous combustion on storage

Is more difficult to ignite and produces a shorter flame

None of these

6 / 50

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.

7 / 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__________?

High sulphur content in the fuel

Low calorific value of the fuel

Presence of large quantity of hydrogen in the fuel

Lack of thorough mixing of fuel with air

8 / 50

?Wobbe index? is a characteristic of___________?

Liquid fuels

Fat coals

Gaseous fuels

Solid fuels

9 / 50

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

Ash

Fixed carbon

Volatile matter

Oxygen

10 / 50

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

Total carbon

Nitrogen

Fixed carbon

Hydrogen

11 / 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

12 / 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 _______?

Higher methane content and thus higher calorific value

Higher carbon monoxide content

Lower carbon dioxide content

None of these

13 / 50

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

Pulverised

High ash

Caking

Non-caking

14 / 50

__________ is used as jet engine fuel ?

LPG

Diesel

Petrol

Kerosene

15 / 50

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

No excess air has been used for combustion

21% excess air has been used for combustion

21% excess oxygen has been used for combustion

Complete combustion of fuel has taken place

16 / 50

A fuel with high heat release rate will__________?

Have high adiabatic flame temperature

Require smaller combustion chamber

Have high calorific value

None of these

17 / 50

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

Bright

Boghead

Splint

Non-banded

18 / 50

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

Neither A. nor B.

No possibility of obtaining complete combustion at high temperature

Always loss of heat from the flame

Both A. and B.

19 / 50

A good quality coal should have _____?

High ash content

High sulphur

Low fusion point of ash

None of these

20 / 50

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

Calorific value

Caking index

Ultimate analysis

Proximate analysis

21 / 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?

20 to 40

1 to 2

3 to 4

5 to 15

22 / 50

A good coking coal should have high _______ content?

Sulphur & phosphorus

Moisture

None of these

Ash

23 / 50

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

Shows little or no fusing action

Burns completely

Gives smokeless burning

None of these

24 / 50

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

Caking index

Ash fusion temperature

Calorific value

Ignition temperature

25 / 50

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

All A., B. & C.

Nuclear fission

Nuclear fusion

Combustion

26 / 50

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

Neither A. nor B.

Fuel

Air

Both A. & B.

27 / 50

Anthracite coal ______?

Contains more volatile matter than bituminous coal

Ignites more easily than bituminous coal

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

Is essentially a coking coal

28 / 50

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

Caking capacity

Fusion point of its ash

Inherent moisture content

Volatile matter content

29 / 50

A coal with high ash content_____?

Is harder and stronger

Is not subjected to washing

Has low quantity of mineral matter

Has higher calorific value

30 / 50

A coal that softens and fuses on heating is__________?

Non-caking

Caking

Classified

Carbonised

31 / 50

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

32 / 50

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

None of these

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

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

Fixed carbon and heating value around 132 BTU/1b

33 / 50

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

Acetylene

Methane

Carbon monoxide

Hydrogen

34 / 50

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

Gobar gas

Carburetted water gas

LPG

Coke oven gas

35 / 50

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

100

36 / 50

A coal having high volatile matter content will _________?

Burn with a small non-smoky flame

Give less yield of tar and gas on carbonisation

Have a very high calorific value

None of these

37 / 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 : 6.39, CO : 1.60, O2 : 3.99, H2O:25.96, N2:72.06

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

38 / 50

Advantages of fluidised bed combustion are ______?

Reduced NOx formation in flue gas

High heat transfer rate

Lower furnace operating temperature

All A., B. & C.

39 / 50

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

Fischer-Tropsch

None of these

Bergius

Lurgi

40 / 50

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

> 280

< 120

300-600

> 120

41 / 50

A good metallurgical coke_____?

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

Should be brittle

Should have high porosity

Should have low fusion point of its ash

42 / 50

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

10.5

14.5

2.5

7.5

43 / 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

Data insufficient; can?t be predicted

Same

44 / 50

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

None of these

Supply of excess fuel

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

Supply of excess air

45 / 50

A coal with high ash content is undesirable, as_________?

All A., B. and C.

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

46 / 50

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

None of these

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

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

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

47 / 50

Anthracite can be used for_____?

All A., B. and C.

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

Making carbon electrodes

Recarbonising steel

48 / 50

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

Porosity

Reactivity

Hardness & strength

Bulk density

49 / 50

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

50 / 50

______ prohibits the use of alcohols directly in petrol engines ?

Low octane number

High cost & availability

Low calorific value

Low flash point

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