Electrical Engineering XYZ MCQs
In thermal power stations, economizer purpose is to:
- Reduce the thermal efficiency
- Reduce the heat
- Both 1 and 2
- Increase the thermal efficiency
Correct answer: 4. Increase the thermal efficiency
Explanation: An economizer in a thermal power station is a heat exchanger that is used to preheat the feedwater before it enters the boiler. The primary purpose of an economizer is to increase the thermal efficiency of the power plant by recovering heat from the flue gases.
Working of economizer
- Flue gases exit the boiler after the combustion process with a high temperature.
- The economizer is placed in the flue gas path before it is released into the atmosphere.
- The feedwater, which is colder, passes through the economizer and absorbs heat from the hot flue gases.
- By preheating the feedwater, the economizer reduces the amount of fuel needed to bring the water to the required temperature in the boiler.
- This process helps in increasing the overall thermal efficiency of the power plant because less fuel is required to produce the same amount of steam.