Low temperature oxidation of coal is accelerated by the

Rate of low temperature oxidation of coal due to bad storage conditions

A

Decreases with increase in surface area

B

Does not vary with increase in surface area

C

Is more for low volatile coal compared to high volatile coal

D

Is accelerated by storage in large heaps with small surface to volume ratio

Low temperature oxidation and spontaneous combustion of freshly mined coal is accentuated, if

A

It contains large amount of volatile matter

B

It is stored in tall heaps

C

Smaller fines are stored in large quantity

D

All of the above

Low temperature oxidation of stored coal results in the

A

Decrease in its caking power & calorific value

B

Decrease in its carbon & hydrogen content

C

Increase in its oxygen content

D

All of the above

Low temperature oxidation of coal during storage does not decrease its

A

Oxygen content

B

Caking power

C

Calorific value

D

None of these

To avoid fire by spontaneous combustion of coal due to its low temperature oxidation, it should be stored in

A

Shallow and small piles

B

Fine sizes without the presence of any lump

C

Closed space without any ventilation facility

D

Large heaps with small surface to volume ratio

Low temperature oxidation of coal resulting from bad storage conditions does not decrease its

A

Caking power

B

Calorific value

C

Hydrogen content

D

Oxygen content

Calorific value of coal middling generated in coal washeries during washing of coal may be around __________ Kcal/kg.

A

1000

B

4000

C

6000

D

8000

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

A

Is less liable to spontaneous combustion on storage

B

Is more difficult to ignite and produces a shorter flame

C

Requires smaller combustion space and less secondary air

D

None of these

The bright glow of a combustion process is the characteristic of __________ temperature oxidation of coal.

A

Fast & high

B

Slow & low

C

Slow & high

D

Fast & slow

Tar yield in the low temperature and high temperature carbonisation of dry coal may be respectively __________ percent.

A

10 & 3

B

3 & 10

C

15 & 8

D

10 & 20

Low temperature oxidation of coal is accelerated by the

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