What is the purpose of maintaining a vacuum within the condenser system and which gas constituent is typically the primary contributor to vacuum degradation?

The purpose of maintaining a vacuum within the condenser system is to minimize the backpressure on the low-pressure turbine, maximizing the turbine's power output and improving overall cycle efficiency. A lower pressure at the turbine exhaust allows the steam to expand further, extracting more energy. The condenser achieves this low pressure by condensing the exhaust steam into liquid water, which occupies a much smaller volume. This creates a vacuum, typically in the range of 2-5 inches of mercury absolute pressure. Air is typically the primary gas constituent contributing to vacuum degradation. Air leaks into the condenser system through various sources, such as faulty seals, flanges, and expansion joints. This air accumulates within the condenser, increasing the total pressure and reducing the effectiveness of the vacuum. Even small air leaks can significantly impact condenser performance. Non-condensable gases like air impede heat transfer, reducing the condenser's ability to condense steam efficiently. Air also raises the partial pressure of water vapor in the condenser, which elevates the turbine backpressure and reduces cycle efficiency. Therefore, detecting and eliminating air leaks is crucial for maintaining optimal condenser vacuum and power plant performance. Continuous air removal systems, such as steam jet ejectors or vacuum pumps, are used to remove non-condensable gases from the condenser.