Increase in ash content of blast furnace coke_________________?

Related Mcqs:

1. Explosion limit of blast furnace gas is 37 to 71% gas in gas-air mixture. It means that the blast furnace gas will explode when burnt in a confined space, if its concentration in the gas-air mixture is _______________ percent?

   A. 71%
   C. In between 37 & 71%
   D. None of these

2. Ash content in the coke produced from a coking coal having 20% ash may be around _____________ percent?

   A. 6
   B. 12
   C. 18
   D. 24

3. Mineral matter content (M) and ash content A. in coal are approximately related as _______________?

   A. M = 1.1A
   B. M = A
   C. M = 1.5A
   D. M = 2A

4. Dust content in raw blast furnace gas is about _______________ gm/Nm3; hence it is cleaned to the dust level of about < 10 mg /Nm3 before use?

   A. 15-30
   B. 1-2
   C. 70-100
   D. 150-200

5. Blast furnace gas is a very poisonous gas because of its predominantly high _______________ content?

   A. H2O
   B. CO2
   C. CO
   D. CH4

6. Fusion point of coal ash increases with increase in its ____________ content?

   A. Iron sulphate
   B. Iron silicate
   C. Lime and magnesia
   D. All A., B. and C.

7. Fusion point of coal ash generally varies from 1000 to 1700° C. Ash having fusion point less than _______________ °C is liable to form clinker?

   A. 1100
   B. 1250
   C. 1350
   D. 1400

8. A coal with high ash content is undesirable, as________________?

   A. It is abrasive to the coal pulveriser (i.e. ball mill) and the combustion chamber
   B. 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
   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
   D. All A., B. and C.

9. During coking of coal, the ash content (percentage)________________?

   A. Increases
   B. Decreases
   C. Remain constant
   D. None of these

10. Coal is heated in presence of air to a temperature of about _______________ °C, while determining its ash content for proximate analysis?

    A. 500
    B. 750
    C. 950
    D. 1100