A Northeast combined cycle gas turbine (CCGT) power plant needed to monitor the efficiency of one of its most critical assets, the steam surface condensers. CCGT plants often operate with minimal staff. For example, these facilities can produce up to 1,000 MW with less than 25 full-time employees. Not to mention, their cycling nature makes using simple parameters such as backpressure to monitor condenser efficiency unreliable. Efficiency losses within a steam surface condenser can result in lost power production, excess fuel cost and additional carbon dioxide (CO2) emissions. All of which negatively impact the performance and profitability of these power producers.
Veolia identified potential cost savings associated with condenser efficiency and employed the Empower digital tool to help the customer visualize and analyze their operating data. Through a collaborative effort with station personnel, the Veolia team identified the critical parameters, created a digital link between the customer’s DCS historian and Veolia’s InSight* platform, and engaged the advanced condenser analytics engine within Empower.
The Empower analytics engine takes raw customer data transferred to the InSight platform and calculates powerful outputs that normalize the data so that condenser performance issues can be quickly diagnosed and critical operating decisions made to maximize profitability and power output. The analytics engine is customized based upon a customer’s design criteria, fuel type and cost.
Empower features an interactive dashboard that displays multiple historical trends of key performance indicators such as cleanliness factor, terminal temperature difference, cooling water velocity, and subcooling and excess fuel cost and carbon dioxide emission penalties due to performance loss. The dashboard is accessible through a secure server to allow station personnel and consultants the opportunity to monitor performance while working remotely.
For the initial six months of the application, the condenser was operating at design with minimal economic or environmental penalties.
Empower then detected a slight loss of condenser cleanliness with an early indication that the loss was being caused by air ingress.
The station reviewed operations and potential sources for air ingress. The root cause for the increase in air ingress was a faulty isolation valve on a condensate pump. The valve allowed air to be drawn back into the condenser when the pump was not in operation. When the station resumed operation, the efficiency of the steam surface condenser returned to design levels.
The early identification of this issue by Empower saved the customer $215,000 (annualized) in excess fuel cost and mitigated the associated carbon increase associated with it.
Figure 1: Condenser Cleanliness Factor (CCF)