This set of Energy Engineering Multiple Choice Questions & Answers (MCQs) focuses on “Fuel Burning Equipments”.
1. What is the function of coal burners?
a) To burn pulverized coal by using secondary air
b) To burn pulverized coal in presence of Primary and secondary air
c) To burn pulverized coal by using induced draught
d) To burn the pulverized coal in short amount of time
View Answer
Explanation: Function of the coal burner is to burn pulverized coal in the presence of primary and secondary air in a boiler furnace. Coal burners are classified according to their design and arrangement in the furnace.
2. Which coal burner is called Long-flame burner?
a) Tangential burner
b) Turbulent burner
c) Stream line burner
d) Cyclone burner
View Answer
Explanation: Stream line burner is called as Long-flame burner, also known as U-flame burner. It is designed to fire downwards in the furnace without any turbulence. Thin flat streams of air and fuel mixture is discharged in the furnace which travels considerably long distance producing long flame.
3. The secondary air in the stream-liner coal burner is fed flames from which direction?
a) At straight angle
b) Opposite to the fuel flow
c) At Right angle
d) Along the fuel
View Answer
Explanation: Heated secondary air in the stream-liner coal burners fed at right angles to the flame. It ensures proper mixing of air and fuel. This type of burner is suitable for burning fuels with low volatile matter as fuel flows at low velocity.
4. Which coal burner has the circular discharge orifices?
a) Tangential burner
b) Stream-line burner
c) Turbulent burner
d) Cyclone burner
View Answer
Explanation: Turbulent is made up of circular discharge orifices or with straight narrow outlets. It is placed in the wall of water cooled furnaces. The fuel and air mixture pass through the burner such that they mix properly at furnace entrance.
5. In which coal burners are fuel and air streams ejected in horizontal direction?
a) Tangential burner
b) Cyclone burner
c) Stream-line burner
d) Turbulent burner
View Answer
Explanation: In tangential burners, fuel and air streams are ejected in horizontal direction tangent to an imaginary circle at the centre of the furnace. The burners are placed at the corners of the furnace to ensure intense turbulence and thorough mixing of fuel and air.
6. Which coal burner is used to burn crushed coal instead of pulverized coal?
a) Cyclone burner
b) Tangential burner
c) Turbulent burner
d) Stream-line burner
View Answer
Explanation: Cyclone burners are used to burn crushed coal instead of pulverized coal. This is to eliminate fly ash handling problems. It consists of a cyclone furnace. Crushed coal of about 8 mm size is fed from the feeder to the centre of the cyclone along with primary air.
7. In which form does the coal burned rapidly in cyclone burner drains down the inner wall of furnace?
a) Powdered
b) In form of small chips
c) Metal slag
d) Gaseous form
View Answer
Explanation: The ash formed due to rapid burning of coal drains down the inner wall of the furnace as molten slag. Hot flue gases along with 10 to 20% of fly ash enter the furnace. Due to centrifugal action most of the fly ash is thrown against the furnace wall and is drained out along with molten slag.
8. Which type of oil burners are used for domestic purposes?
a) Atomizing burner
b) Vaporizing burner
c) Steam jet atomization burner
d) Mechanical atomization burner
View Answer
Explanation: The vaporizing burners are used for domestic purpose especially in portable air heaters, cooking stoves etc. petromax stove which burns kerosene is a classical example of a vaporizing burner. Here an upward moving high velocity fuel jet is allowed to strike against hot moving plate. The vapor burns with a short intense flame.
9. Which type of oil burners are commonly used in oil-fired furnaces of steam generators?
a) Vaporizing burner
b) Mechanical burner
c) Atomizing burner
d) Air jet burner
View Answer
Explanation: Atomizing burners are very commonly used in oil-fired furnaces of steam generators. The oil is divided into fine particles to increase the surface area of contact with the combustion air. Due to atomization a homogeneous mixture of oil and air is produced which is fired in the furnace.
10. How is oil pressurized in mechanical atomization of atomizing burner of oil burners?
a) By positive displacement pumps
b) By centrifugal pumps
c) Helicon-axial pumps
d) Electric submersible
View Answer
Explanation: In mechanical atomization of atomizing burner of oil burners, the oil is pressurized by using a positive displacement pump. It is used in high capacity steam generating furnaces. In order to improve efficiency and flow conditions the viscosity of the oil is reduced by heating it to about 120oC.
11. How does atomization of fuel occur in an atomizing burner of oil burner?
a) High pressure movement of fuels
b) By spraying the fuel at high pressure
c) By impinging two streams of fuel
d) By spark ignition method
View Answer
Explanation: In the atomizing burner, oil is delivered under pressure through a central tube. Steam or air is supplied along the annular space between the oil pipe and the concentric outer tube. Near the tip of the burners the two streams impinge resulting in atomization of fuel.
12. Which type of gas burner is used to control flame length?
a) Ring burner
b) Sealed burner
c) Electric burner
d) Standing pilot burner
View Answer
Explanation: Ring burners are used to control the flame length. The rate of gas flow can be controlled by using dampers. The gas flows through an annular ring, whereas air is induced both around and within the annular ring.
Sanfoundry Global Education & Learning Series – Energy Engineering.
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