Steam surface condensers are large and complex heat exchangers widely installed in power plants to cool the exhaust steam from the turbine and convert it back to water for reuse. These condensers condense the steam at a low pressure. For a power plant to function reliably and safely, the tubing quality of the condenser is crucial. However, certain issues may arise pertaining to these condensers, such as air and water leaks or tube fouling, which, if not addressed, may impact their functioning and the efficiency of steam turbine power plants. These issues may occur due to their huge size, design complexity, and many seals. This post discusses some steam turbine problems and solutions along with some steps to enhance condenser performance with the help of condenser-related measuring instruments.

Common Problems in Steam Surface Condensers and Their Solutions

Here are some common problems in steam surface condensers and their solutions.

  • Fouling issues in condensers: This happens due to organic or inorganic material deposits, such as calcium carbonate, rock silt, and clay, that block the water circulation and inhibit heat transfer. To identify this, you must know the total circulating water flow rate to identify reduced flow or reduced heat transfer. Choose an instrument that monitors total flow rate.
  • Air leakage: Leakage into the condenser can come from a multitude of sources including turbine seals, expansion joints, or broken/cracked condenser penetrations. There are many penetrations and seals in a steam surface condenser; hence tracing the exact air leakage location can be time-consuming and costly. Aside from this air, condenser configuration may also be a contributing factor for excess condenser pressure. Some instruments can quantify air in-leakage. Choose an instrument to accurately calculate this leakage by directly measuring vent line gas parameters.
  • Excess condenser pressure: This issue occurs due to air in-leakage, air-bound zones, vacuum equipment deficiency, or fouling, and is one of the most obvious causes of reduced power plant efficiency and downtime. It leads to reduced generation or increased fuel consumption which causes lost revenue. To rectify this issue, it is wise to get an analysis of the condenser configuration from a professional service provider to recover lost load and reduce back pressure.
  • Dissolved gases and corrosion: Water is rarely in its purest form and contains dissolved oxygen (DO) as well as other gases that corrode the steam tubes. Corrosion directly impacts condenser tubes, sheets, and related components. A high DO percentage may not always be linked with high air in-leakage. The condenser configuration in this case may not be sufficient and will need correction.
  • Maintenance, cleanliness, and operational issues: In spite of maintenance and repairs, poor heat rate may be an issue that impacts the functioning of the power plant. This can happen in spite of low air in-leakage and a normal pump capacity as many plants function with high back pressure and low heat transfer coefficients. This leads to lost load and a high heat rate. For this, the condenser performance must be reviewed step by step. This includes studying the condenser design, comparing it with the original configuration, and analyzing the issue. Also, condenser tubes must be cleaned on a regular basis. The cleanliness factor (CF) is calculated by measuring the ratio of the actual heat transfer coefficient as a percentage of the associated HEI specified design heat transfer coefficient.

Steps for Condenser Performance Evaluation

Here are some steps you can take to improve condenser performance.

  1. The first step is to partner with a professional and experienced service provider to measure the condenser-related parameters in your power plant.
  2. A knowledgeable service provider will check all the aspects of the condenser operation.
  3. Ensure you get the necessary data for performance evaluation, which the service provider can analyze, generate reports, and offer actionable solutions.
  4. Ensure you track and trend the back pressure and establish a regular cleaning schedule.
  5. Ensure you have all the design and documentation as the service provider may need them for reviews to evaluate current operating deficiencies.

Are you a part of the power sector and planning to monitor your steam turbine power plant? If yes, consider the quality and functionality of the instruments used for monitoring various condenser-related parameters. The Bionetics Corporation is one of the leading manufacturers of measuring instruments and provides associated data monitoring and diagnostic services. Our RheoVac condenser monitors measure air in-leakage, pump capacity, and other significant parameters to provide a continuous picture of condenser operation, which helps improve the performance of your power plant. You can contact our team today via email at sales-flow@bionetics.com or phone at 614-895-0301 for more information.