7EA USERS GROUP

Webinar effective for technology, regulatory updates

Many powerplant supervisory personnel who could benefit from attending user group meetings often do not get to the annual conferences covering their gas turbines. Some have never gone. You know the usual reasons: internal meetings, no travel budget, short-staffed, etc.

For those who attend at least every other conference, 12 or 24 months is a long time to go between meetings and many things you should be aware of, but might not be, can happen during that time. Examples include new regulations, new/revised OEM technical information letters, best practices, equipment upgrades, etc.

Pat Myers, a member of the 7EAUsers Group steering committee , understands well the challenges of managing a multi-unit powerplant while trying to keep up with the seemingly endless number of equipment, personnel, ownership, and regulatory changes that characterize the generation sector of the electric power industry today.

Example: In addition to his day job as plant manager of American Electric Power Co’s Ceredo Generating Station, Myers was selected to head a special corporate committee charged with reviewing and upgrading, where necessary, AEP’s practices for the safe handling and combustion of natural gas. This included compliance with NFPA® 56, “Provisional Standard for the Commissioning and Maintenance of Flammable Gas Piping Systems,” which was being developed in parallel with the AEP initiative.

Myers, who spent more than two decades in the employ of a major gas transmission company before joining AEP, recognized that NFPA 56 would be a “game changer” regarding traditional practices of handling and burning natural gas at powerplants. He believed it was important for the industry to understand the safety standard’s requirements as soon as it was made public.

Owner/operators of 7B-EA engines worldwide were invited to participate at no cost in the user-only event, which was sponsored by Allied Power Group LLC,Houston. There were 88 owner/operators signed on when the webinar started and 53 were still connected when the “meeting” ended nearly two hours later. The broadcast had been scheduled for one hour but the presentations typically ran 15 minutes rather than the planned 10 and Q&A averaged more than 10 minutes per speaker.

Host for the webinar was Amy Alix, an engineer in Progress Energy Florida Inc’s Combustion Turbine Operations group, and member of the 7EA User Group’s steering committee. CCJ Senior Editor Scott Schwieger was responsible for the behind-the-scenes work in the “broadcast booth.” The webinar was not recorded.

The technical program was as follows:

• “NFPA 56, What You Need to Know to Protect Personnel and Property,” Mike Bethany, lead mechanical engineer, CEC Combustion Services Group, Cleveland.Bethany, CEC President John Puskar’s back-up on the NFPA 56 committee, is an expert in gas purging by virtue of his onsite involvement in dozens of such projects.
• “7EA R2 and R3 Bucket Rail Loss Repair Options and Preventive Measures,” Aaron Frost, technical director, Allied Power Group LLC,Houston. Frost is one of the industry’s top experts in the repair of HGP parts.
• “Control System Upgrades,” Glenn Corbiere, operations supervisor, Stony Brook Energy Center, Massachusetts Municipal Wholesale Electric Co (MMWEC), Ludlow, Mass. Corbiere profiled the conversion of four 7Es from Mark II control systems to PLC-based controls and one 7E converted to DLN-1/Mark V in 1993 to PLC-based controls.
• “Onsite Hot Section Fir Tree Build-up,” Pat Long, engineer, Calpine Corp’s Turbine Maintenance Group. Long has spent three decades on the
• deck plates doing what was necessary to get plants back in operation. This was the first time he had participated in a user group meeting.
• “Bucket-Rock Solution: Reduce Turning-Gear Speed,” Ken Knecht, maintenance foreman, Beluga Power Plant, Chugach Electric AssociationInc. Knecht, a millwright by trade, has been repairing, and supervising repairs to, gas turbines for 30+ years. This was the first time he had participated in a user group meeting.

NFPA 56.

CCJ has followed the development of NFPA 56 since Myers first brought it to the editors’ attention more than a year ago. Early details on the safety standard appeared in both the journal and CCJONsite, an electronic letter that reports on developments at user-group meetings. Access the 2011 Outage Handbook at www.ccj-online.com and read “NFPA 56 a ‘game changer’.”

Bethany’s presentation reviewed much of the material in that article and went a step further by telling webinar participants what they should do now that the provisional standard was “official.” First, he hammered home the point that OSHA compliance starts with a consensus standard being in effect. Non-compliance with a consensus standard usually is the basis for an OSHA citation.

While the designation “provisional standard” may appear to have only “baby teeth,” that thought couldn’t be further from the truth. It only means that the standard’s development was expedited. The possibility of an OSHA citation for not heeding it is very real.

For those who were caught unawares and take issue with some of the standard’s requirements, note that NFPA’s automatic revision cycle has already begun and new comments are being accepted. This standard will become a “code” as soon as a state adopts it into law.Connecticut, where the fatal gas explosion at the Kleen Energy combined cycle occurred in February 2010, is one state likely to do that.

Bethany urged everyone to buy a copy of the code at www.nfpa.org ($33.75) and read it. Next, develop the required implementation plan for your operation. This is very important: You must have a plan and it must include procedures, a hazard review process, and training. More specifically:

• Procedures for the retrofit of systems to enable safe purging and reintroduction of gas.
• Detailed plans for routine gas practices.
• Checklists for hazard review processes.
• Training of employees and monitoring of contractor personnel.

Be prepared, the expert noted. The implementation plan will impact regular operational activities and organizational and personnel behaviors will have to change.

To learn more, email CEC’s Puskar (jpuskar@combustionsafety.com) for a copy of his whitepaper summary highlights of NFPA 56.

Bucket rail loss

Allied Power Group’s Technical Director Aaron Frost reviewed rail-loss repair options and preventive measures following the Q&A onBethany’s presentation. Although Frost’s focus was rail loss on 7EA R2 and R3 buckets, the wear issue is problematic for owners of other engines as well—such as Frame 6B and 7FA+e R2 and R3 buckets and 501FD R3 turbine blades. Thus many users outside the 7EA community can benefit from what he said.

The problem, Frost said, is that in many instances the honeycomb becomes a cutting tool and machines away the tip rail of shrouded turbine buckets/blades (Fig 1). He noted that GE Energy uses a cutter-tooth design for its shrouded buckets, whereas Siemens does not. But in either case, he continued, the chance that the honeycomb machines off the bucket rail or that the bucket rail wins is the same (Fig 2).

The crux of the wear problem, Frost said, is that the Haynes 214 (GE) and Hastelloy X (Siemens) honeycomb materials oxidize over time, forming either an aluminum oxide or chrome oxide surface scale during exposure to high temperatures. Both oxides are abrasive and capable of machining away bucket/blade rails (Fig 3).

Allied’s proven method for preventing such damage is to coat rails with an abrasive plasma-deposited aluminum oxide coating (Figs 4, 5). This makes the bucket/blade the cutting tool instead of the honeycomb. It also eliminates the need for cutter teeth, improves seal effectiveness, and protects the side of the rail against wear associated with rotor movement during startup and shutdown. Finally, the removal of cutter teeth improves long-term shroud and airfoil creep life because of the reduction in weight.

Houston-based Allied, long a supporter of user-group activities, sponsored the 7EA User Group’s first webinar.