Fuels and Combustion

311.Quantity of coke oven gas produced by high temperature carbonisation of one ton of dry coal may be around _________ Nm3.

  1. 30
  2. 300
  3. 3000
  4. 30000

Correct answer: (B)
300

312.Quantity of coke produced from metallurgical coal may be around _________ percent.

  1. 30
  2. 50
  3. 75
  4. 95

Correct answer: (C)
75

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

  1. Decreases with increase in surface area
  2. Does not vary with increase in surface area
  3. Is more for low volatile coal compared to high volatile coal
  4. Is accelerated by storage in large heaps with small surface to volume ratio

Correct answer: (D)
Is accelerated by storage in large heaps with small surface to volume ratio

314.Ratio of primary air to secondary air increases with increase in the rank of coal, because the

  1. High rank coals have higher amount of volatile matter
  2. Ratio of fixed carbon to volatile matter increases
  3. Oxygen content progressively decreases
  4. Calorific value of the coal increases

Correct answer: (B)
Ratio of fixed carbon to volatile matter increases

315.Removal of hydrogen from coke oven gas

  1. Increases its calorific value
  2. Decreases its calorific value
  3. Does not alter its calorific value
  4. Is not possible on commercial scale

Correct answer: (A)
Increases its calorific value

316.Safe condition for storage of high V.M. bituminous coal is that

  1. Height of the coal heap should be < 3 metres
  2. Maximum 200 tons should be stored in a heap
  3. Both (A) and (B)
  4. Neither (A) nor (B)

Correct answer: (C)
Both (A) and (B)

317.Shatter index of metallurgical coke on 2 inches and 0.5 inch screen should be respectively around _________ percent.

  1. 80 and 97
  2. 95 and 100
  3. 40 and 70
  4. 25 and 97

Correct answer: (A)
80 and 97

318.Shatter index of the coke is a measure of its

  1. Strength
  2. Bulk density
  3. Reactivity
  4. None of these

Correct answer: (A)
Strength

319.Short/intense flame is produced during combustion of gaseous fuel by using

  1. High amount/current of combustion air
  2. Low amount/current of combustion air
  3. Preheated secondary air
  4. Very little excess air

Correct answer: (A)
High amount/current of combustion air

320.Soft coke is not

  1. Produced by low temperature carbonisation of coal
  2. A domestic fuel
  3. Used in blast furnaces
  4. None of these

Correct answer: (C)
Used in blast furnaces

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