Siemens meeting focuses on issues, solutions, technology developments for large frames

Siemens Energy Inc’s first technical conference for owner/operators of its F, G, and H gas turbines, held Sept 14-17, 2015 at Walt Disney World’s Dolphin Hotel in Orlando, was rated a “success” by attendees sharing their views with the editors after the meeting. Approximately 130 users from across the globe participated. CCJ’s editorial team, unable to attend this meeting because of schedule constraints, asked Siemens’ Christie Robinson, representing the frame-owner office and product-line managers, to prepare the summary below.

Ed Bancalari, head of Siemens’ large gas turbine product line opened the conference with an overview of the agenda. His presentation focused on fleet growth, global customer base, market drivers and dynamics, big data and digitalization, and the importance of operational flexibility.

Highlights of the four-day meeting included new customer orientation, presentations by the OEM’s technical experts, closed user sessions, networking opportunities, a vendor fair, and a multi-day Siemens equipment/services showcase.

Mature-F Frame Owner Shantanu Natu directed a “deep dive” on F through FD3 engines. Jonathan Mount opened the session with a presentation on spin cool/hot restart and the company’s Direct Air Injection System (DAIS). One goal was to communicate the value of blade-tip clearance analysis for the compressor and turbine sections; plus, the process changes made to better accommodate spin cool and hot restart, based on recent engine tests. Improvements planned for the DAIS was another discussion topic.

Mount was followed at the podium by Jonathan Swasey, presenting on rotor and casing inspection and evaluation (RCIE), Tarik Chehab on the air separator, and Dan Welsh on bearings. Swasey summarized recent inspection findings and offered updated recommendations on what to look for during planned overhauls. Chehab and Welsh also presented on recent findings and made recommendations on inspection procedures, and on component repair and/or replacement.

Final topic in the first day’s session was Row 4 turbine-blade seal pins, by Veronica Arocho-Pettit. She reviewed fleet findings and explained product improvements to mitigate issues experienced by some owner/operators.

Track topics on the second day included operation on fuel oil, blade-path spread, turning-gear time reduction, and rotor air cooler. The deep dive concluded with presentations on plant optimization and mods and upgrades. Later, the users met in a closed session to critique content provided by Siemens; the steering committee of engine owners/operators communicated the feedback to Natu and his team.

Advanced F-class sessions (F4 and above), conducted in parallel with the mature-F sessions, was coordinated by Frame Owner Elizabeth Loveland. The main technical issues, addressed first, were these:

      • Enhanced single-piece exhaust (Stephen Bawer).

      • Compressor locking bolt (Bart Pepperman and Mark Adamson).

      • Inlet cracking and expansion-joint cracking (Javier Jimenez).

The company’s solution to address exhaust cracking experienced by the advanced fleet has been installed on all F4s and later models and appears to have completely eliminated the problem. The solution for the locking-bolt issue is available and recommended for installation only if the compressor cover is removed for other reasons. Finally, work to mitigate inlet cracking continues; the redesigned expansion joint is in commercial service and meeting expectations.

Other presentations on the first day included starting system, lube oil system, rotor cooling-air system, compressor water-wash recommendations, and bearings. Improvements to the DAIS were presented as well, followed by lessons learned and best practices for successful operation on liquid fuel.

On Day Two, Siemens updated users on what’s new in the 501Fs coming off the assembly line today and the upgrades available for use on advanced engines already in service. Siemens’ capabilities to optimize combined-cycle operation also were shared with attendees. The day concluded with a closed session for customers and presentation of an action-item list to Loveland and her team.

G fleet. The topic generating most discussion in the W501G session, chaired by Frame Owner Mark Carter, was an update on the turbine-rotor through-bolt failure issue. Rusty Van Hoose presented the latest fleet findings and mitigation program activity. Highlights since the last 501G meeting included the following:

      • Report of an additional bolt fracture event.

      • Comparison of findings from a rotor that had achieved a full service interval (two majors) without a bolt fracture to findings from rotors suffering bolt failures.

Root-cause findings for the most recent bolt fracture are consistent with those identified for the previous events: Specifically, debris accumulation contributing to high contact stresses which caused fretting fatigue cracks to initiate and propagate to a high-cycle fatigue (HCF) crack and eventual overload rupture. While debris also accumulated on the through bolts of the rotor that had achieved its full service interval, those bolts did not reveal the same type of damage identified with the failed bolts. Further, they did not exhibit the same indications of iron oxide formation (magnetite versus hematite) and water staining.

Because the most recent bolt fracture occurred on a rotor that had some mitigations applied, robust discussion ensued regarding the effectiveness of those mitigations as well as on the latest recommendation of low-plasticity burnishing. LPB is a surface treatment intended to greatly improve a through-bolt’s margin against both fretting and HCF crack initiation and propagation by adding a deep compressive residual stress field to the bolt surface. A review of LPB testing was provided, highlighting very favorable results on fatigue resistance tests and open actions for additional ongoing tests—such as material debit and thermal mechanical exposure.

Jonathan Swasey followed with a review of findings and recommendations on turbine debris because of its connection with bolt fractures. Other key presentations included a report by Dilshan Canagasaby on improvements to DLN combustion systems for increased operability and durability. Shervin Rodd led an informative and lively discussion on fleet performance, comparing power output and turbine-inlet-temperature variations and their potential relationship to exhaust-temperature values. He also reviewed how performance characteristics compare with emissions and combustor flashback indications and the potential of improvement options.

Siemens 8000H engine owners and operators came together for the first time at the Orlando conference. Because an H steering committee had not been formed prior to the meeting, the OEM directly asked its customers for help in developing an agenda. Frame Owner Dave Lawrence arranged the program in four sessions over two days, as follows:

1. Frame overview and fleet status, followed by an update on the company’s global service strategy for the H frame and planned mods and upgrade products.

2. Operational issues. A Q&A session following prepared presentations allowed users to dive deeper into specific topics.

3. Updates on the steam turbine and generator product lines compatible with the 8000H gas turbine.

4. User session for open discussion and to collaborate on additional questions to present to Siemens engineers.

Steamers, generators, etc. Multiple parallel-track breakouts were conducted following the gas-turbine sessions to update attendees on generators, KN and HE steam turbines, service and repair technologies, and training. Here are some notes from each track:

 Generator (air- and hydrogen-cooled) presentations/discussions covered service bulletins, field service capabilities, inspections, and maintenance practices. Also, a well-received introduction to new products—such as fiberoptic frame foot loading, high-frequency thermographic test, and generator life assessment.

 Service and repair technologies focused on recent developments in welding, coating, and brazing. Hardware was displayed in different stages of repair. Technologies covered included tools for in-situ and smart inspections, tools and techniques for field service, processing of big data, and addressing the challenges of a growing global fleet.

Steam turbine sessions reviewed details of the KN and HE frames, and discussed maintenance, outage planning, and available upgrades. A presentation on maintenance scopes and typical outage findings got high marks. Other topics covered included spare parts, outage kits, valves, titanium blades, and bearings.

Safety was an interactive session led by Will Weatherford, which included an overview of Siemens’ “Zero Harm Culture” and “Personal Commitment” programs. Chris Kopec and Keith Dean discussed innovations in field-service safety, highlighting human performance, hand safety, and line-of-fire/situational awareness.

The session concluded with a case study by Salman Khan on the challenges and opportunities in implementing safety programs—including best practices and lessons learned. Real-time audience polling provided feedback on content, revealing alignment on the need for an organizational safety culture and continuous human-performance improvement. Results also showed attendees acknowledged Siemens as a thought leader that walks the talk.

Controls included detailed presentations on T3K implementations, field experience, the version 7.2 upgrade, cybersecurity, and recent logic improvements for increased reliability and robustness.

The training track included an overview of the OEM’s power diagnostic center and how it is integrated with day-to-day plant operations, using real-world examples. The plant training group discussed different modules offered by Siemens for personnel training. A voice-of-the-customer session was conducted for feedback and to solicit ideas for further improvements.

The equipment/services showcase mentioned at the beginning of this article continued throughout the week. Highlights included the following:

      • Advanced hardware—including the H combustor and “Next Gen” G basket.

      • Parts improvements: bellybands, F-frame VGP (Value Generation Program) R1 and R2 turbine blades, and F-frame exhaust configurations.

      • Turbine vane repair.

      • Advanced maintenance tools—including robotic crawler, vision scope, and inspection trailer.

      • Advanced generator maintenance—including SIEMONplus monitoring system and FastGen tooling.

      • Steam turbine blades.

      • Steam turbine erosion experience.

      • Field service displays—including human performance kit, tooling examples.

Mark your calendar. The Siemens 2016 Customer Meeting will be held September 19-22 in Orlando. Golf and a pre-conference event are scheduled for September 18. Write Kelly Lewis (kelly.lewis@siemens.com) or Dawn McCarter (dawn.mccarter@siemens.com) to receive more details on the 2016 conference as they become available.

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