A. Produces more slag when used in the blast furnace
B. Has poor strength and abrasion resistance
C. Is desirable in producer gas manufacture
D. None of these
Related Mcqs:
- 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 - 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 - A fuel containing carbon and carbon monoxide (but containing no hydrogen or its compounds) is burnt in pure oxygen at constant pressure. Its gross calorific value as compared to net calorific value will be_________________?
A. More
B. Less
C. Same
D. Data insufficient; can’t be predicted - 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. - 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 - Gasification of the solid fuel converts its organic part into combustible by interaction with air/oxygen and steam so as to obtain a secondary gaseous fuel of high calorific value having no ash. Gasification reactions are normally carried out at about _____________ °C?
A. 400-500
B. 900-1000
C. 1400-1500
D. 1700-1800 - 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 - A liquid/gaseous fuel containing hydrocarbons and high amount of sulphur is burnt with 40% excess air. The flue gas still contains large amount of carbon monoxide. This may be due to the_________________?
A. Presence of large quantity of hydrogen in the fuel
B. Low calorific value of the fuel
C. High sulphur content in the fuel
D. Lack of thorough mixing of fuel with air - A coal containing high amount of volatile matter will have__________________?
A. Low ignition temperature
B. Very little ash content
C. High fusion point of its ash
D. Low adiabatic flame temperature - A coal containing very high percentage of durain is called ______________ coal?
A. Bright
B. Splint
C. Non-banded
D. Boghead
