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

Related Mcqs:

1. Mineral matter, ‘M’ and ash percentage ‘A’ in coal are roughly related as_______________?

   A. M = 1.8 A
   B. M = 0.5 A
   C. M = 1.1 A
   D. M = A

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. 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

4. 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

5. 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

6. 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.

7. 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.

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

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

9. Softening temperature of coal ash is a measure of the _____________ of coal?

   A. Caking tendency
   B. Coking tendency
   C. Clinkering tendency
   D. Size stability

10. Gas yield in the Kopper-Totzek coal gasifier is about ______________ Nm3/ton coal (ash = 35%)?

    A. 150
    B. 1500
    C. 3500
    D. 5000