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

Related Mcqs:

1. 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

2. 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

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

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

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. 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

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. A coal with high ash content___________________?

   A. Has higher calorific value
   B. Is harder and stronger
   C. Is not subjected to washing
   D. Has low quantity of mineral matter

8. 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.

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

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

10. 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