Overview

GE Power assists with rotor life management and extension at El Bajío Power Plant in Mexico to avoid outages and boost efficiency.

The challenge

Operators at El Bajío Power Plant (operated by Saavi Energía, an ACTIS company) were facing a crossroads in 2012 when they evaluated the long-term plan for the combined-cycle plant. The primary source of dependable power in the region in central Mexico, the power plant was commissioned in 2002 and is rated for 646MW of power, including 3x 7FA gas turbines in combined-cycle with 1 x D11 steam turbine. In 2012 the plant operators realized a plant overhaul was required to support the growth and needs of the Bajio market industry long term. 

The solution

Deciding on a solution early enabled the operators to make the most of cycle times for part manufacturing, improve outage labor efficiencies and utilize a seed rotor concept to reduce overall cost. 

Start planning early... very early

Considering a range of rotor life management solutions

Operators began planning in 2012—three years ahead of the expected outage. They evaluated the long-term viability of the plant, as well as ways to enable decades of safe operation, which meant they were able to look at many rotor and operating solutions.

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We knew our customers need reliable power in the region long-term, and GE was the right partner to help us get there.

Enrique Serrano

El Bajío Power Plant Manager

After analyzing different options, they decided to execute a mid-life rejuvenation of their 7FA gas turbines to almost double the viable life of the gas turbines and thereby the power trains. Deciding on a solution early enabled them to make the most of cycle times for part manufacturing, improve outage labor efficiencies and leverage utilizes a seed rotor concept to reduce overall cost. 

After considering many alternatives, in 2014 they selected General Electric to complete the mid-life rejuvenation. 

A tale of three rotors

In 2015 the project began to extend the life of the 3 power trains installed in 2002. A seed rotor (in this case a new rotor) was sent to the El Bajío site to be installed into the first of 3 gas turbines getting a mid-life rejuvenation.

The rotor removed from the first gas turbine was sent to the GE service shop in Greenville to be overhauled. At the GE Service shop this rotor was disassembled, inspected, repaired and updated with the latest in compressor and turbine rotor technology. It was sent back to the El Bajío site just in time to be installed in the second unit in 2017.

content-seed-rotor-diagram
content-seed-rotor-diagram

Similarly, the used rotor from the second unit was sent back to the GE Service shop to be refreshed and was used in the 3rd El Bajío gas turbine during the outage in 2018. Leveraging Using the seed rotor concept enabled the operator to stay within the outage window required because the rotor arrived at site before the outage began and was installed when needed without becoming the pacing item during the outage.  The final rotor that was removed from the unit in 2018 was returned to GE to be put into their refurbished rotor pool.  

Benefits of seed rotors

The seed rotor concept that the El Bajío leaders used is leveraged employed by many operators that have multiple F-class gas turbines. “The seed rotor let us install a rotor solution that worked best for us during the outage window,” said Serrano. 

The seed rotor concept that the El Bajío leaders used is leveraged employed by many operators that have multiple F-class gas turbines. “The seed rotor let us install a rotor solution that worked best for us during the outage window,” said Serrano.

Not all plants can take the longer outage needed with service work like rotor life extensions, which require a shop inspection, repair, and tear-down. Although significant work has been done to reduce the lead-time of such work, sometimes operators need to get back online fast.

Using a seed rotor to do a series of rotor life extensions is a best practice in the industry. It creates the flexibility of selecting an economical solution while eliminating the outage risk. Many operators who do not have time to do a rotor life extension during an outage use the seed rotor concept by installing a refurbished or new GE rotor. A refurbished rotor is from the GE pool of used rotors that have been inspected and updated with the latest technology to maintain safe long-term operation.

Looking to the future

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Working with GE was a great experience. Our series of rotor life extensions laid a solid foundation for our later upgrade work.

Enrique Serrano

El Bajío Power Plant Manager

The El Bajío plant continues to provide safe and reliable power to its customers in Mexico. In 2020 they added more incremental power to the plant by collaborating with GE again.