A coal with high ash content is undesirable, as

A It is abrasive to the coal pulveriser (ie.g. 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 of the above

Correct Answer: All of the above

Bissoy MCQ
#Chemical Engineering #Fuels and Combustion

Related Questions

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A 15 to 25
B 35 to 45
C 55 to 75
D 75
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A M = 1.1A
B M = A
C M = 1.5A
D M = 2A
Cavitation in a pump creates so many undesirable effects. Out of the following, which is not an undesirable effect created by cavitation?
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A Has higher calorific value
B Is harder and stronger
C Is not subjected to washing
D Has low quantity of mineral matter
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A Caking tendency
B Coking tendency
C Clinkering tendency
D Size stability
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A Increases
B Decreases
C Remains constant
D None of these
Fusion point of coal ash increases with increase in its __________ content.
A Iron sulphate
B Iron silicate
C Lime and magnesia
D All of the above
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A 500
B 750
C 950
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The popular notion that a tree's age can be determined by counting number of internal rings in its trunk is generally true. Howeevr, to help regulate the internal temperature of the tree, the outermost layers of wood of the Brazilian ash often →peel away when the temperature exceeds 95 degrees Fahrenheit, leaving the tree with fewer rings than it would otherwise have. So only if the temperature in the Brazilian ash's environment never exceeds 95 degrees Fahrenheit →elav eing the tree with fewer rings than it would otherwise have. So only if the reliable measure of the tree's age. Which of the following is an assumption on whish the argument above depends?
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D The internal rings of all tress are of uniform thickness
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B 70 : 20 : 10
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D None of these

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