Pesqueria Power Plant: Three medals for best practices
The pandemic did not bring operations to a halt—and neither did it affect the drive to make improvements nor the ensuing recognitions. Three projects at the Mexican plant have been awarded the CCJ 2020 Best Practices Awards for achieving improvements in procedures.
Being able to rationally produce energy at the lowest cost while maintaining high availability and safety standards means that plant personnel has to do the "little things" better than the competition. Three improvement projects undertaken by the team at the Pesqueria Power Plant (Central Eléctrica Pesquería - CEP) were singled out for recognition by the trade magazine Combined Cycle Journal in its 2020 Best Practices Awards. The publication commends the best practices achieved by combined cycle plants throughout the world in a yearly ranking: the 2020 announcements were initially delayed by the pandemic.
The CEP was inaugurated in 2016 to supply energy to the Ternium and TenarisTamsa mills in Mexico: in 2019, with the endorsement of plant manager Miguel Ontiveros, three improvement projects were selected as entries for the contest which covers a total of nine categories. Each project was written up with technical details highlighting the key innovations and achievements and published in the US-based magazine’s most recent issue.
With proven success as a common factor, the projects ranged from the application of Lean procedures for the plant stoppage to optimizing steam turbine cooling processes and redesigning the sulfuric acid dosing system to eliminate leaks. These practices were all developed, tried, tested, and implemented by company employees, who worked with contractors and technical consultancies to benefit not only the plant, but the industry as a whole, and drive sustainable growth.
1- Lean method to reduce downtime
The first general plant shutdown for major maintenance was held in 2018, providing the opportunity for a diagnosis of critical pathways and pain points, all recorded on a board in the boardroom. "Once we’d completed this exercise and identified eight key crunch points, we began our search for a methodology that would be easy to implement and solve the issue of how to tackle those points," explains Carlos Rodríguez, in charge of project proposals. "The challenge was how to shorten the timing for scheduled shutdowns and optimize resources while ensuring people’s safety and that of our equipment."
The Engineering department came up with the proposal to apply Lean methodology--which focuses on optimizing an organization’s people, resources, efforts, and energy with a view to creating value--and involved both the entire Operation and Maintenance team and an external consultant. By the time the second and third general plant stoppages came around in 2019, execution time had been cut by 15% compared to the first one in 2018, which took 19 days.
2 - Optimization of turbine cooling
2019 was also the year when the first major maintenance was scheduled for the steam turbine (which works alongside three other gas ones at the plant). An earlier analysis had detected that cooling the steam turbine would involve carrying out an operation that fell beneath the standards of the minimum power supply guarantee, implying inefficient operation and higher costs.
“The challenge was to come up with a methodology to cool the steam turbine in the shortest time possible while respecting the cooling curves and complying with the minimum contractual generation load,” explained Rodríguez, who was on duty at the plant when the proposal was in its early stages. They laid out the problem before the turbine suppliers and the ensuing joint analysis determined that the requirements could be met by using a dry air cooling method. This meant that the forced cooling of the steam turbine was possible, enabling a generation to continue at above 400 megabytes without any incident, also gaining thirty hours of turbine operation compared with the standard method.
3- Water management: a success story
The CEP water treatment plant sources greywater from Monterrey's public sewer system and can produce 1,000 cubic meters per hour. The water is treated to meet the necessary quality standards for use in the cooling circuits, the plant's steam cycle, and various other services essential to circuit operations. However, the sulfuric acid dosing system involved in the operation, which has a 21 m3 tank, a distribution system, and 11 pumps, had been leaking since the plant began operations.
"The challenge was about correcting this problem at its roots, because of the risk and impact of these leaks on both personnel and our facilities as a whole," said Carlos Rodríguez. A work team was set up and took the decision to completely overhaul the piping system, design included: the success of the initiative was evident in the complete lack of leaks during 1,440 hours of operation after they had put the new system to work.