1. Why should be a metallurgical coke porous in nature?
a) To increase its calorific value
b) To provide contact between carbon and oxygen
c) To decrease its ash content
d) For its easy storage
Explanation: When the metallurgical coke is porous then it becomes easy for the carbon present in it to make contact with oxygen so that the combustion process can be done efficiently of the fuel in the furnace. It increases the rate of combustion.
2. What happens when coke breaks into fine particles during the charging of the furnace?
a) It increases the rate of combustion
b) It cools down the temperature of furnace
c) It chokes the air passages
d) It stops the whole process
Explanation: When the coke break downs into fine particles, it hinders the flow of gases an choke the air passages. This happens due to the incomplete combustion of coke since it is broken into small pieces.
3. Why can coal not be used as a metallurgical fuel?
a) Because of its less purity
b) Due to its high calorific value
c) Due to the high cost of it
d) Due to the presence of less impurities
Explanation: Coal does not have necessary purity, porosity and strength. Coal can be used as metallurgical fuel only in reverberatory furnaces. This leads to incomplete combustion, thus affecting the metallurgical processes
4. How can we obtain liquid coal synthetically?
a) Carbonisation of coal
b) Hydrogenation of coal
c) By heating of coal
d) By cooling of coal
Explanation: Highly volatile bituminous coal is used for the hydrogenation process. The hydrogenation of bituminous coal produces liquid hydrocarbons which have a number of uses in many processes. It is obtained by the Bergius process.
5.In which processes does the low boiling fractions of petroleum are used?
a) Petrol engines
b) Diesel engines
c) Oil fired furnaces
d) Kerosene engines
Explanation: At low boiling fractions of petroleum least amount of impurities are left and since the efficiency petrol engine decreases with the increase in the amount of impurities, these fractions are used in petrol engines. At high boiling fractions, diesel engines and oil fired furnaces are used
6. Which of the following fuel requires less storage space?
a) Methane gas
b) Coal
c) Cow dunk
d) Kerosene
Explanation: Liquid fuels require less storage space as compared to solid and gaseous fuel. Kerosene weigh 30% less and occupy 50% less space than coal of equal heating value. Gaseous fuel are weigh very less, but their storage requires a big space.
7. Liquid fuels leave ash content after burning.
a) True
b) False
Explanation: Both liquid and gaseous fuel does not produce ash content after burning as solid fuel. The problem of clinker formation is totally absent in case of liquid fuel.
8. Which type of combustion is seen in liquid fuel?
a) Uniform and complete combustion
b) Non-uniform and complete combustion
c) Uniform and incomplete combustion
d) Non-uniform and incomplete combustion
Explanation: The rate of combustion in the case of liquid fuels can be controlled easily. Also since there is no ash generation in liquid fuel, it undergoes complete combustion.
9. Which of the following fuel does not requires excess air for its combustion?
a) Coal
b) Cow-dunk cake
c) Diesel
d) Charcoal
Explanation: Liquid fuel such as diesel does not require excess air for their combustion, they normally start combustion on catching fire where as in solid fuels excess air is required for the process of combustion. Pulverised coal does not require excess air for combustion.
10. Liquid fuel produces _____________ odours on incomplete combustion.
a) Pleasant
b) Unpleasant
c) No odours
d) Fruity
Explanation: Sometimes due to the presence of impurities, incomplete combustion of liquid fuel occurs which produces very unpleasant odours which can also be hazardous for health. For this process purification method is used.