Electrical Engineering XYZ MCQs
Gas turbine power plants for maximum efficiency may have:
- Heat exchangers
- Multistage compression
- Reheating
- All of above
Correct answer: 4. All of above
Explanation:
Gas turbine power plants utilize gas turbines to convert the energy of gas combustion into mechanical energy, which is then used to generate electricity. To maximize the efficiency of these power plants, several techniques are employed:
- Heat exchangers: Heat exchangers can be used to recover waste heat from the exhaust gases of the gas turbine. This recovered heat can then be used to preheat the air entering the combustion chamber or to generate steam for additional power generation in a combined cycle configuration. Heat recovery improves the overall efficiency of the plant by utilizing energy that would otherwise be lost.
- Multistage compression: Gas turbines typically require compressed air for combustion. Multistage compression involves compressing the air in several stages to achieve higher pressures before it enters the combustion chamber. This increases the efficiency of the combustion process and improves power output.
- Reheating: Reheating involves passing the exhaust gases from the gas turbine through a heat exchanger to raise the temperature of the gases before they enter the turbine again. This process increases the energy available for the turbine, improving its efficiency. Reheating is particularly effective in combined cycle power plants, where the exhaust gases are used to generate steam for additional power generation.
So, while heat exchangers and multistage compression are indeed techniques used to improve the efficiency of gas turbine power plants, the option “Reheating” encompasses these techniques and adds an additional efficiency-enhancing process, making it the most comprehensive choice. Therefore, the correct answer is “All of the above.”