Fuels and Combustion Quiz 1

1 / 50

A coal having high volatile matter content will _________?

Give less yield of tar and gas on carbonisation

Have a very high calorific value

Burn with a small non-smoky flame

None of these

2 / 50

?Fat? coal means a coal having _____?

Low calorific value

High volatile matter

Low ash content

Non smoking tendency

3 / 50

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

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

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

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

None of these

4 / 50

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

Ultimate analysis

Proximate analysis

Calorific value

Caking index

5 / 50

A fuel with high heat release rate will__________?

None of these

Have high adiabatic flame temperature

Require smaller combustion chamber

Have high calorific value

6 / 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

Complete combustion of fuel has taken place

21% excess oxygen has been used for combustion

No excess air has been used for combustion

7 / 50

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

Lurgi

Fischer-Tropsch

Bergius

None of these

8 / 50

A coal having high amount of volatile matter______?

Ignites easily and burns with long smoky flame

Produces very little of tar and gas on carbonisation

All A., B. and C.

Would require smaller combustion chamber

9 / 50

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

Caking index

Calorific value

Ignition temperature

Ash fusion temperature

10 / 50

A coal with high ash content_____?

Is not subjected to washing

Has higher calorific value

Has low quantity of mineral matter

Is harder and stronger

11 / 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

12 / 50

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

Nitrogen

Total carbon

Fixed carbon

Hydrogen

13 / 50

A good metallurgical coke_____?

Should be brittle

Should have high porosity

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

Should have low fusion point of its ash

14 / 50

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

15 / 50

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

None of these

Supply of excess fuel

Supply of excess air

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

16 / 50

A coal having higher volatile matter content, has lower__________?

Chance of catching fire during storage in open space

Coke oven gas yield on carbonisation

Ignition temperature

Smoking tendency on burning

17 / 50

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

Boghead

Splint

Non-banded

Bright

18 / 50

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

Non-caking

Pulverised

Caking

High ash

19 / 50

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

< 120

> 280

300-600

> 120

20 / 50

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

Carbon monoxide

Acetylene

Methane

Hydrogen

21 / 50

?Wobbe index? is a characteristic of___________?

Gaseous fuels

Fat coals

Solid fuels

Liquid fuels

22 / 50

______ prohibits the use of alcohols directly in petrol engines ?

Low calorific value

Low flash point

Low octane number

High cost & availability

23 / 50

Anthracite coal ______?

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

Ignites more easily than bituminous coal

Contains more volatile matter than bituminous coal

Is essentially a coking coal

24 / 50

A coal containing high amount of volatile matter will have___________?

Very little ash content

Low adiabatic flame temperature

Low ignition temperature

High fusion point of its ash

25 / 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 : 6.26, CO : 1.56, O2 : 3.91, H2O :15.66, N2 : 72.60

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

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

26 / 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

None of these

Lower carbon dioxide content

27 / 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 __________?

None of these

Is less liable to spontaneous combustion on storage

Requires smaller combustion space and less secondary air

Is more difficult to ignite and produces a shorter flame

28 / 50

A coal with high ash content is undesirable, as_________?

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.

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

29 / 50

A good quality coal should have _____?

None of these

Low fusion point of ash

High ash content

High sulphur

30 / 50

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

No possibility of obtaining complete combustion at high temperature

Neither A. nor B.

Always loss of heat from the flame

Both A. and B.

31 / 50

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

32 / 50

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

Caking capacity

Fusion point of its ash

Inherent moisture content

Volatile matter content

33 / 50

__________ is used as jet engine fuel ?

Diesel

Petrol

Kerosene

LPG

34 / 50

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

Hydrocarbons

Hydrogen

Carbon monoxide

Oxygen

35 / 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?

5 to 15

20 to 40

3 to 4

1 to 2

36 / 50

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

Speed of the fan

Variation in the pitch of the fan blades

Damper

All A., B. and C.

37 / 50

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

Nuclear fission

All A., B. & C.

Nuclear fusion

Combustion

38 / 50

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

Reactivity

Bulk density

Porosity

Hardness & strength

39 / 50

A good coking coal should have high _______ content?

Ash

None of these

Moisture

Sulphur & phosphorus

40 / 50

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

Fixed carbon

Ash

Oxygen

Volatile matter

41 / 50

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

100

42 / 50

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

Gives smokeless burning

Burns completely

Shows little or no fusing action

None of these

43 / 50

Anthracite can be used for_____?

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

Making carbon electrodes

All A., B. and C.

44 / 50

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

LPG

Gobar gas

Carburetted water gas

Coke oven gas

45 / 50

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

Neither A. nor B.

Fuel

Both A. & B.

Air

46 / 50

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

7.5

2.5

10.5

14.5

47 / 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

Lack of thorough mixing of fuel with air

Low calorific value of the fuel

Presence of large quantity of hydrogen in the fuel

48 / 50

A coal that softens and fuses on heating is__________?

Caking

Non-caking

Classified

Carbonised

49 / 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

50 / 50

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

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

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

Fixed carbon and heating value around 132 BTU/1b

None of these

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