Electronic log enables tighter control of boiler chemistry
Challenge. The need for proper control of boiler chemistry is well known. An important part of any operator’s shift involves monitoring of boiler chemistry parameters and taking action to ensure they are maintained within posted specifications. The actions in real time help assure long-term integrity of boiler systems and, by extension, plant reliability.
There are time limits on how long chemistry parameters can be out of spec. For example, EPRI’s “Action Levels” establishes the time limits based on the severity of the out-of-spec parameter.
When logs were maintained on paper, tracking the time boilers operated in these levels was cumbersome—if done at all. The challenge to South Point staff: Find a more efficient way to track chemistry action levels to allow better decisions on boiler chemistry control.
Solution. Chemistry logs at South Point now are maintained in an electronic software format. The logs include the date and time of the analysis and the readings for the chemistry parameter.
If an out-of-spec reading is found while taking chemistry readings, the operations team responds immediately, taking appropriate steps to return chemistry to the proper control band.
The application used allows downloading of the data to an Excel format. The spreadsheet has the capability to flag when parameters are out of spec. The date and time stamp allows calculation of how long the out-of-spec condition lasted. Then the out-of-spec time periods can be added to determine the time in each action level. Posting the results on a monthly basis gives staff and management insight into the efficacy of the chemistry control plan.
Results. By monitoring the plant’s adherence to chemistry action levels, the efficacy of the plant’s chemistry control plan can be measured and acted upon. Tracking magnitude and time of out-of-spec chemistry parameters can offer insight into potential future maintenance issues.
Sharing of this information with the operations staff can foster ownership of the chemistry control program. Trending improvements attributed to the chemistry control program over time could become part of an incentive plan.
Project participants:
Kurt Fetters, plant manager
Darren Otero, operations manager
Stan Avallone, Calpine chemistry program manager
Vincent Powers, plant engineer
South Point Energy Center
Calpine Corp
580-MW, gas-fired, 2 × 1 combined cycle powered by 501FD2 gas turbines, located in Mohave Valley, Ariz
Plant manager: Kurt Fetters
