FRAME 6 USERS GROUP: Expanding the value proposition of participation for owner/operators

The need to do more with less should not surprise anyone in the electric power industry these days. Even user groups are putting the pedal to the metal to help make a new generation of engineers and technicians productive more quickly than, perhaps, ever before in peacetime.

Staffing at a typical 2 × 1 F-class combined cycle with a nameplate rating of 550 to 650 MW, for example, is 18 to 24 employees based on an informal survey by the editors. That’s 10% or less of the staffing level at a traditional coal-fired plant of similar capability where new employees primarily learned “on the job.” That training regimen doesn’t work with so few employees. And it’s the rare employer that’s going to send someone off for a month-long training program given the expense. Also, who’s going to do the work when the trainee is gone?

The steering committee of the Frame 6 Users Group recognizes this and has integrated a 6B-frame-specific course on engine design, operation, and maintenance into the organization’s annual meeting for the first time this year (see box for details). The discussion leader is the eminently qualified John F D Peterson, one of the founders of the user group with more than three decades of relevant engine experience.

The half-day course, Monday afternoon, June 11 (the day before the conference begins), will be fast-paced and conducted in four sessions of about 50 minutes each, with short breaks between them. Each attendee will receive a course workbook with descriptions of components, definitions of technical terms specific to the 6B, a listing of common operational and maintenance issues, etc. This document will be an invaluable aid for the meeting and in the plant afterwards.

Here’s a summary of the subject matter included in the course:

  • Design history of the Frame 6B.

  • Performance characteristics.

  • Instrumentation, controls, and protection.

  • Generator issues.

  • Review of “The “Green” Books,” including schematics, alarm list, etc.

  • Glossary of 6B jargon.

  • Failure mechanisms (low- and high-cycle fatigue, creep rupture, oxidation, etc) and modifications made to key components since the engine’s introduction.

  • Typical maintenance scopes for HGP and major inspections and how intervals are determined.

  • What to expect in the upcoming user sessions, vendor fair, and GE Day.

Anyone who knows John Peterson will tell you this session alone is worth the conference registration fee. Few know as much about this frame as he does.

Another benefit of participation in this group is access to engine-focused webinars between annual meetings. This helps keep users engaged throughout the year. The first such webinar, held in early March, focused on repairs technologies and lessons learned. More webinars will be conducted going forward.

Attendee profile. Frame 6B gas turbines are the heart of many cogeneration systems, and the O&M personnel responsible for them are a breed apart from most users the editors meet at industry meetings. The typical 6B user is a highly experienced “lifer” responsible for keeping steam flowing from his or her cogen facility to one or more process units.

The lives of 6B owner/operators rarely are controlled by a grid contract, by the need to “fill in” around must-take renewables, or by power prices. In their world, electricity is simply a byproduct of steam production, a world where an empty steam pipe means you might well be looking for employment elsewhere tomorrow.

Such a challenging environment is conducive to a practical solutions-driven mindset. It’s not news that some cogen-plant owners consider power production a “necessary evil” and keep O&M budgets lean, opting to spend on process facilities first. Their belief is that end-product investments will produce a better return—at least until a gas turbine is forced out of service.

Adding to the financial challenge is that many cogen facilities are not supported by a corporate engineering staff, and instead rely heavily on the talents of very-capable deck-plates personnel. The Frame 6 Users Group contributes to success by providing a “technical solutions lifeline” for its membership and the reason many of these people continue to attend meetings year after year—some since the group was founded 30 years ago.

Agenda. Meetings begin on Monday evenings with a welcome reception and dinner. Tuesday is reserved for open discussion sessions among users, plus presentations by owner/operators and invited providers of equipment and services. It concludes with a vendor fair that runs from 5 p.m. until 8:30—a long day. Wednesday is GE Day. Thursday morning (the formal meeting concludes at noon) has the same format as Tuesday.

Sessions on Tuesday and Thursday are dedicated to presentations and open discussion on safety, auxiliaries, generators and excitation systems, I&C, compressor section, combustion section, and turbine section.

Safety roundtable. Co-chairs Jeff Gillis and Sam Moots (members of the steering committee are identified in the box) called the meeting to order, made a few announcements, and reviewed the hotel’s emergency evacuation plan—a perfect segue to the opening roundtable discussion on safety. Gillis may be the ideal session leader on this topic given his global perspective. He has engineering management responsibilities at ExxonMobil for generating equipment worldwide, which requires learning how other countries and cultures assure worker safety and learning their regulations. OSHA is not global, and America does not have all the answers.

The 2017 safety forum may have been the most meaningful ever at a user group meeting in the editors’ experience. It ran from the opening bell to the morning coffee break—nearly two hours. Fire protection was the first topic. A user charged with replacing his plant’s Halon system wanted to know from attendees what they would do and why. He had been thinking CO2 but thought it expensive.

ExxonMobil prefers water mist today, the moderator said. Another user who had experienced a few Halon discharges and found it difficult to get refills, opted for CO2. The switchover was relatively simple, he said. Spray nozzles had to be modified but the piping basically was fine the way to was—except that the CO2 bottles took up more space than the Halon ones.

He was not familiar with safety procedures concerning door opening and entry with CO2 armed. It was brought to the group’s attention at this point that recent 6Bs, made in Belfort, France, are built to different standards than the legacy machines made here. They initiate a unit trip when you open the compartment door.

Another user said that during commissioning of his facility, the CO2 system was armed a little too early and the plant experienced a release with people in the compartment. Thankfully, no one was hurt. He suggested a lock on the CO2 valve or a blank flange to prevent such an accidental release.

Someone else offered that a challenge at his plant was getting operators to close the compartment door properly after entry. Not much protection from CO2 with a door ajar. Maintenance of door handles was stressed as at least part of the solution to avoid a safety breach of this type.

Problems encountered in identifying failing or failed sensors was another subject brought to the floor. Proper wiring is important the group was told. Be sure the temperature limit of your wiring is above the compartment temperature. Poor-quality conduit should be avoided, too. One contributor to the discussion said at his plant they wire sensors to relays to identify failed sensors.

 Haz-gas detection was the next subject. An attendee said the detectors installed in his unit, made in Belfort, must be calibrated every 360 days or they go to a “false state.” Others in the room suggested a six-month interval, to be on the safe side. One user mentioned that his units run 12 to 18 months between maintenance outages. Because they can’t get inside to maintain their detectors were moved outside the package.

In Europe, the owner/operators were told, a unit will trip if there’s no air flow through the package, to protect against a gas leak. This was considered too conservative by at least one user because you may trip the machine unnecessarily. He suggested a runback instead of a trip on haz-gas detection. About half of the users in attendance said they had in-package haz-gas detection capability. Most do not shut the gas valve as a first action when alerted; rather, they opt for a runback or fired shutdown.

Next topic was safety when performing maintenance on top of the unit. No easy fleet-wide solution given the variety of plant/equipment arrangements. Restraint systems require a free fall of 6 ft or so to work properly; plus, there’s a weight limit that may not be compatible with structural members at the tie-off point. Scaffolding may be the best solution in many cases.

One user created a diagram of tie-off points, where you need PPE, scaffolding, etc, because there typically are new safety personnel for each outage and they will interpret codes differently. Having this information available beforehand they know what’s required and won’t drive site people crazy. CCJ