What is the largest heat exchanger in a steam plant?

What is the largest heat exchanger in a steam plant?

• A. Condenser
• B. Boiler
• C. Economizer
• D. Superheater

Answer: (A)

The key idea here is heat rejection from the steam cycle. The condenser is the largest heat exchanger because it must remove the enormous amount of latent heat from all the steam exiting the turbine and condense it back into water. This requires a vast surface area cooled by circulating cooling water, making the condenser the biggest device for transferring heat out of the steam cycle and returning condensate to the feed system. The boiler's job is to add heat to water to generate steam, so its purpose is heating, not cooling. The economizer uses waste heat from flue gases to preheat feedwater, but the amount of heat it handles is far less than what the condenser must reject. The superheater increases the temperature of steam after it's generated, which is still a heating operation rather than a large-scale heat rejection.

The key idea here is heat rejection from the steam cycle. The condenser is the largest heat exchanger because it must remove the enormous amount of latent heat from all the steam exiting the turbine and condense it back into water. This requires a vast surface area cooled by circulating cooling water, making the condenser the biggest device for transferring heat out of the steam cycle and returning condensate to the feed system.

The boiler's job is to add heat to water to generate steam, so its purpose is heating, not cooling. The economizer uses waste heat from flue gases to preheat feedwater, but the amount of heat it handles is far less than what the condenser must reject. The superheater increases the temperature of steam after it's generated, which is still a heating operation rather than a large-scale heat rejection.