A good coking coal should have high __________ content.

Prime coking coal is always blended with medium or non- coking coal before ear-bonisation

A

To check against its excessive swelling during heating, which may exert high pressure and damage coke oven walls

B

Because, it alone produces unreactive coke

C

Both A & B

D

Neither A nor B

The coking process normally mostly used in Indian oil refineries is the __________ coking process.

A

Delayed

B

Flexi

C

Fluid

D

Contact

Volatile matter content in coking coal may be about __________ percent.

A

1

B

7

C

22

D

46

During coking of coal, the ash content (percentage)

A

Increases

B

Decreases

C

Remains constant

D

None of these

Coking time in a commercial high temperature coal carbonisation plant is about __________ hours.

A

6

B

18

C

28

D

36

Which of the following petrographic constituents of coal is non-coking?

A

Durain

B

Vitrain

C

Clarain

D

Fussain

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

Ash content in the middling coal (a byproduct of coal washeries) in India ranges between __________ percent.

A

15 to 25

B

35 to 45

C

55 to 75

D

75

Very __________ coals are completely devoid of cokability i.e, it is non coking.

A

Young

B

Mature

C

Both A & B

D

Neither A nor B

Coking time in narrow by-product coke ovens is around __________ hours.

A

18

B

48

C

8

D

80

A good coking coal should have high __________ content.

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