Assam (India) coals suffers mainly from the disadvantage of high ______________ content?

Related Mcqs:

1. ‘Fat coals’ are those coals which have very high____________________?

   A. Caking capacity
   B. Volatile matter content
   C. Fusion point of its ash
   D. Inherent moisture content

2. High ash coals ____________________?

   A. Are soft & friable (poor strength and size stability)
   B. Require longer time of carbonisation as ash offers resistance to heat transfer
   C. Produce larger quantity of coke oven gas
   D. None of these

3. 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

4. Coals used for the generation of producer gas should have ____________________?

   A. High caking index
   B. Low fusion point of ash
   C. High volatile matter content
   D. Very low ash content (8-10%)

5. Coking coals are invariably____________________?

   A. Lignites
   B. Bituminous coals
   C. Semi-anthracites
   D. Anthracites

6. High sulphur content in a fuel ______________ of the flue gases?

   A. Decreases the dew point
   B. Increases the dew point
   C. Reduces the combustion efficiency by limiting the permissible temperature reduction
   D. Both B. and C.

7. A good coking coal should have high ______________ content?

   A. Ash
   B. Sulphur & phosphorus
   C. Moisture
   D. None of these

8. 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

9. A coal having high volatile matter content will ________________?

   A. Give less yield of tar and gas on carbonisation
   B. Burn with a small non-smoky flame
   C. Have a very high calorific value
   D. None of these

10. 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.