Condenser Pressure and Air In-Leakage

Surface condensers, such as large shell and tube heat exchangers, play a vital role in power generation by condensing the steam used in the process back into water. Cooling water flows through tubes within an air-tight shell, creating a sub-atmospheric pressure vacuum-tight space where the steam exhausted from the turbine generator condenses. If air and other non-condensable gases (known as ‘air in-leakage’) are not effectively removed from the steam space, they can hinder heat transfer and upset water chemistry in the condenser.

Effects of Air Leakage in Steam Condenser

If air in-leakage is not effectively managed, it can lead to:

• Excess turbine backpressure: Air in-leakage can increase the pressure in the condenser, causing operational issues.
• High dissolved oxygen: This can promote corrosion.
• Corrosion or ammonia grooving: High dissolved oxygen can damage materials.
• Increased plant heat rate: Air in-leakage can make the plant less efficient.

Condenser air in-leakage must remain within the capacity of the exhausters, as exceeding this limit raises condenser pressure. When air in-leakage exceeds the capacity of the air removal system, the condenser pressure rises, and additional exhauster capacity must be used. Exceeding the exhauster capacity leads to inefficiencies and increased costs. A slight increase in backpressure can cause significant operational costs, making air leakage inspections a cost-effective investment with immediate returns.

Condenser Air In-Leak Survey

Helium leak testing for condensers often leads to guesswork and trial-and-error fixes during outages to confirm results. Bionetics effectively uses continuous air in-leak monitoring to complement helium leak detection, providing precise quantification of leaks identified during testing. Quantifiable air in-leak surveys utilize Helium leak detection in conjunction with RheoVac condenser monitoring technology.

A ball valve fitting in the air extraction line between the condenser and vacuum system enables the installation of a RheoVac air in-leak probe. This setup supports temporary or permanent monitoring of air leaks and exhauster capacity for steam jet air ejectors or liquid ring vacuum pumps. To learn more about the RheoVac Air In-Leak monitor probe, click here.

Key Benefits of Air-in Leakage Surveys

A condenser air in-leakage survey provides critical benefits, including:

• Conducting routine inspections to ensure the condenser operates efficiently and consistently.
• Verifying system integrity before an outage to identify repair needs and post outage to confirm successful repairs.
• Performing emergency inspections when the unit struggles to maintain optimal efficiency, enabling prompt issue resolution.

How Does it Work?

The inspection starts on the steam turbine deck, systematically covering all areas within the vacuum boundary from top to bottom. This includes valves, flanges, rupture diaphragms, pump seals, and other vacuum components. Helium is applied to these components, and any leaks allow helium to enter the steam space. The helium is then carried to the air removal system, where a spectrometer detects it at the discharge. The leak source is recorded, and suspected leaks are temporarily sealed, if possible. The RheoVac instrument immediately quantifies any changes, providing precise measurements of the leak’s impact.

Our condenser air in-leak survey identifies the severity and location of leaks while offering potential repair solutions. Bionetics Engineers conduct the condenser air in-leak survey with meticulous attention to detail, ensuring comprehensive and accurate results. The survey provides clarity and confidence in addressing air in-leakage issues. Additionally, the RheoVac instrument can remain on-site, enabling steam power plant personnel to validate repairs and ensure ongoing system efficiency.

Want to Learn More?

If excess air in-leakage affects your condenser’s performance, let Bionetics help you quantify and resolve the issue effectively. Contact us using the form on this page or call us at the number at the top of the page to discuss your condenser performance. You can also visit our Contact Us page for more ways to reach us.