Enhancing Plant Efficiency through NUHR and Condenser Testing Case Study

Our client's power generation unit was experiencing suboptimal net unit heat rate and condenser performance, leading to decreased efficiency, and increased operational costs. The challenge was to identify the root causes of these issues and develop strategies to enhance the unit's overall performance.

Net Unit Heat Rate (NUHR) refers to the quantity of heat required to produce 1 kWh (also known as a Unit) of electricity. Poor condenser performance can lead to a reduction in turbine heat rate due to reduced LP efficiency.

To address the challenge, a comprehensive study was conducted by our team of experts. The study involved a series of tests, analysis, and evaluations to identify the factors impacting the net unit heat rate and condenser performance. The following steps were undertaken:

1.      Test Guidelines and Objectives: The team established test objectives, ensuring compliance with ASME Performance Test Codes and relevant international standards.

2.      Performance Test Protocol: A detailed performance test protocol was developed to ensure consistency and accuracy throughout the testing process.

3.      Data Collection and Analysis: Extensive data collection was carried out, including turbine output, turbine heat rate and boiler thermal efficiency corrections utilising HRL’s test instrumentation.

4.      Test Limitations and Tolerances: The limitations and tolerances of the testing process were considered, ensuring that the results were acceptable based on nominated standards and codes.

5.      Water Tightness Test: A water tightness test was conducted to assess the integrity of the condenser and identify any potential leaks or inefficiencies.

1.      Identification of Performance Deviations: It was identified that the unit's performance deviated from established design. These deviations included lower turbine output, higher turbine heat rate, and lower boiler thermal efficiency. The team also identified deviations in the condenser performance which were low vacuum levels and high cooling water temperatures.

2.      Root Cause Analysis: A thorough root cause analysis revealed several issues, including fouling of condenser tubes, air ingress in the HP condenser, and imbalanced gas flow pattern in the boiler. The team also identified potential issues with the main condensate flow, such as incorrect installation of the orifice plate and foreign objects blocking the flow path.

The team provided several recommendations to the client to improve the unit's performance. These recommendations includes: -

1.      Cleaning of condenser tubes

2.      Air ingress investigation for the HP condenser

3.      Gas flow pattern balancing via boiler tunning exercise

4.      Inspection of main condensate nozzle

Overall, the recommendations provided by the team were aimed at improving the unit's performance by addressing the root causes of the suboptimal net unit heat rate and condenser performance. These recommendations, if implemented, could improve the unit's performance, reduce operating costs, and increase profitability.