1. Which type of burners are used for mixing of coal powder and air?
a) Turbulent burner
b) Pressure jet burner
c) Rotatory cup burner
d) Dual fuel burner
Explanation: Turbulent burner is an atomising burner which is used to mix fuel and air to produce a flow. Dual fuel burner cannot be used in this case as the physical state of both are different
2. Which type of firing technique is employed for pulverised coal?
a) Oxidation firing
b) Reduction firing
c) Front wall firing
d) Raku firing
Explanation: The pulverised coal is burnt along the front side of the burner. It can be done in more three ways, i.e. side wall firing, U-flame firing and corner firing respectively. U-flame firing is not used so much as it produces a very long flame.
3. Which method is used for reducing fly ash?
a) Dry bottom
b) Slag-tap
c) Cyclone burner
d) Corner firing
Explanation: Fly ash is the ash produced by burning the pulverised coal. 75% of fly ash is deposited around the surrounded places. When the pulverised coal is burnt is slag-tap furnace, its flame is directed towards and sweeps over the bed of molten slag where the particles of ash are caught.
4. All types of coals can be converted into coke.
a) True
b) False
Explanation: All types of coals cannot be converted into coke. Only that coal which has a tendency to soften, swell and stick together during strong heating in absence of air can be coked
5. The process of converting coal into coke is called ______
a) Coking
b) Carbonization
c) Decarbonization
d) Isomerization
Explanation: The process of converting coal into coke is called carbonization. When coking coal is heated in absence of air, porous, strong and hard residue left is called coke
6. Depending on the behaviour of the coal, when it is heated in the absence of air, it can be categorized into ______ categories.
a) 2
b) 3
c) 4
d) 5
Explanation: Depending on the behaviour of the coal, when it is heated in the absence of air, it can be categorized into 2 categories, Coking and Non-coking coals.
7. Which coals are suitable for metallurgical purposes?
a) Coking
b) Carburized
c) Non-coking
d) Decarburized
Explanation: Coking coals are suitable for metallurgical purposes because they are quite strong and not crushed under the weight of ore.
8. Only bituminous type of coal can be coked.
a) True
b) False
Explanation: Only that coal which has tendency to soften, swell and stick together during strong heating in absence of air can be coked. This property is found only in the bituminous type of coal
9. Caking coal with ______ content are used for gas manufacturer.
a) high volatile matter
b) low volatile matter
c) high ash content
d) high moisture content
Explanation: Caking coal with high volatile matter content are used for gas manufacture whereas caking coal with low moisture matter content is used for the manufacturing of metallurgical coke.
10. Practically, coking coals are blended with ______
a) caking coals
b) non-caking coals
c) non-coking coals
d) lignite
Explanation: Coking coals are blended with non-caking coals since it helps in increasing the rate of carbonization and producing good quality coke from non-caking coal.