1Q 2012 – Business Partners
Latest concern for 7FA users: S1 tip liberation
Rod Shidler and Mike Hoogsteden of Advanced Turbine Support LLC (ATS), Gainesville, Fla, met with the editors during the Western Turbine
Users Group meeting and passed on photos of an S1 tip liberation at the 6 o’clock position that caused extensive damage to a 7FA flared compressor (Figs 1, 2). This event occurred the first week of March and was the second such incident witnessed by the engine inspection experts at ATS.
Save! Only a couple of weeks later, Shidler emailed the photo of a cracked S1 stator vane found by one of its inspectors the first week of April (Fig
3). The plant had asked ATS, based on a published report of the accident described above, to check S1 vanes while it was performing the OEM-recommended inspection of S0. How many more starts did this vane have left before the tip liberated?
The OEM, to the editors’ knowledge, has not issued a Technical Information Letter pertaining to S1 airfoils. The closest the manufacturer comes is with its TIL 1509-R3 which addresses R0, R1 and S0. This document recommends an annual visual inspection for R0 root cracking, R0/R1 tip discoloration, rolled metal, and/or tip loss. It provides detailed recommendations if any of those deterioration mechanisms are identified. For S0 stator vanes, inspection personnel are urged to look for trailing-edge cracks and if found immediate replacement is recommended.
Team ATS is not in complete agreement with the recommendations in TIL 1509-R3. It believes that annual visual inspections are not sufficiently comprehensive and have the potential to miss small or tight indications that could result in blade liberations and a catastrophic compressor event. Proof: The company’s inspection experts have identified multiple rotor-blade cracks with visible dye penetrant that were not seen during unaided visible inspections.
In addition, ATS’s state-of-the-art eddy-current inspection tools have identified S0 trailing-edge stator-vane cracks in the initiation phase that measured smaller than 0.080 in. These indications were not identified visually, even with the use of fluorescent dye. Company personnel also have found S0 leading-edge and radial-tip cracks in both flared and unflared compressors, which are not addressed in TIL 1509-R3. To those indications, you can now add the S1 experience.
ATS has recommended for several years dye-penetrant inspection of R0/R1 blades and dye-pen or eddy-current inspections of S0 vanes annually or every 100 fired starts. Subsequent inspections based on the results of the initial investigations would run parallel to the OEM’s recommendations. More recently it has recommended eddy-current inspections of S1 because of the earlier liberation.
a base-load unit that had logged more than 55,000 hours of operation. The plant is not located in the so-called “Ring of Fire” near the coastline where some engine parts generally are believed more susceptible to damage. ATS visually inspected the unit only by borescope in November 2011, at the customer’s request. Vibration signature changed in December but the unit did not trip and continued in service until the spring inspection when the damage was discovered.
Shidler said ATS can eddy-current check all the vanes in S0 and S1 during a top-on inspection. The company’s technicians can also get to some vanes in rows S2 and S3. He added that inspecting S1 after an eddy-current inspection of S0 only adds about 25% to the invoice.
DRS celebrates 10 years of vane pinning
Rodger Anderson, manager of gas turbine technology for DRS-Power Technology Inc, Schenectady, NY, called to say that the pin locking system he developed to prevent shims used in the vane rows of GE frames from protruding and liberating into the flow stream quietly passed its 10th anniversary (Fig 4).
More than 120 turbines worldwide are running with over 80,000 pinned vanes. Fleet hours total more than 3 million; multiple fleet leaders have passed 48,000 hours. Reliability is 100%—meaning there have been no vane failures or shim liberations since the first vanes were pinned.
The pin system also locks the vanes into a robust ring segment which stops fretting wear caused by loose vanes in the casing grooves. Pinning technology restores the vanes and shims to their “as new” positions without installing patch rings. This improves gas turbine performance by as much as 0.3%, Anderson said, which translates into an annual fuel saving of up to $150,000 for a base-load 7FA.
The compressor expert said the following GE engines are benefitting from pinning: Frame 5, 6B, 7EA, 9E, 6FA, 7FA, and 9FA. Pinned vanes are operating in Southeast Asia, Middle East, UK, Australia, and throughout the Americas.
SPS, ORAP® celebrate 25 years of service to the industry in 2012
Since 1987, Strategic Power Systems Inc, Charlotte, has processed and added to its ORAP database plant operational, failure, and maintenance data representing more than 22,000 unit years and over 280,000 forced, scheduled, and unscheduled outages. Today, information from over 2000 gas and steam turbines are reported on a monthly basis for review and validation prior to being entered into ORAP. It is these data that allow SPS to provide RAM benchmarks for use in the energy market for both heavy duty and aeroderivative plants across the various OEMs, technologies, applications, and duty cycles.
Data come to SPS from a variety of plant sources, including onsite operators and maintenance personnel, as well as from central operations staff. In some cases, SPS obtains operating data directly from the unit control or onsite historian; however, outage detail must always come from site or central staff.
Kevin Million, 49
Kevin Michael Baker Million, a senior plant operator at the Klamath Cogeneration Facility, Klamath Falls, Ore, died early in January 2012. Previously he worked for Fresno Cogeneration, following eight years in the US Navy where Million served as a gas turbine mechanic and nuclear field operator.
Team Klamath remembers him as always being concerned about his immediate family as well as his work family. One of several duties at the Oregon plant was onsite chemist.
Million is survived by Jan, his wife of 28 years, and children Makayla and Brandon.
Andrew Lazarus, 87
Andrew Lazarus, founder of New York City-based public relations agency, A J Lazarus Associates, died early in January 2012 in Portland, Ore. “Back in the day” he was well known in the power generation industry, with such blue-ribbon clients as Curtiss/Wright, ABB Power Generation/Alstom, Rolls-Royce, ASME Gas Turbine Div, and Black & Veatch.
Andy Laz, as he was called by industry friends, started his agency in 1968 and retired in 2004, succeeded as president by his daughter, Chris Lazarus. He began his industrial PR work at Dow Chemical, then Gulton Industries, before going on to head PR departments for two New York advertising agencies.
Gas turbine consultant Sep van der Linden (article, p 120) had this to say, “Who could forget his class, his enthusiasm? He had the nose of a hound, one capable of sniffing out any news item that could be used to positively place a client in good light. Give Andy a few thoughts and he could produce a world-class news release. We met when I was at Curtiss/Wright and he followed me to ABB, characteristic bow tie intact and with that big smile of his.”
This editor remembers Andy Laz as the person who introduced him to the emerging land-based gas turbine industry, and its leaders (van der Linden among them), in the early 1970s. He was a true professional in a difficult business, fine writer, persuasive, well respected, and all around “good guy.” Lazarus, a small-town person with a big-city degree (MA in literature from Columbia Univ), served in the Army Air Force in the Pacific during WWII and launched his civilian career as a correspondent for the NY Herald Tribune in Europe. He had a lifelong passion for the people and culture of Europe, as well as a never-ending curiosity about nearly everything.
Edward W Clark Generating Station, NV Energy, recently completed work to protect migrating birds from coming into contact with high-salt/solids water in two of the plant’s evaporation ponds. The station is in-line with certain bird-migration pathways and the company’s Environmental Services and Power Generation teams worked closely with the US Fish & Wildlife Service and Nevada Dept of Wildlife to protect the fowl.
About 7 acres of netting now covers the two ponds (Fig 5); reflective flags used previously were ineffective. Four other ponds are available for the birds to use for resting and watering. More than 300 support poles and high-tension cable were required to support the netting.
North Pole GT Plant, Golden Valley Electric Assn, was honored by HRSG manufacturer, IST, as the recipient of its 2011 Plant of the Year Award during Power-Gen International last December.
Rio Nogales Power Plant, an 800-MW combined cycle is purchased by CPS Energy from Tenaska Capital Management LLC to facilitate the utility’s transition to clean energy. Rio Nogales will replace the energy output of the J T Deely coal-fired plant planned for service in 2018.
NV Energy, like many other utilities , is trying to improve the safety consciousness of its employees. It’s “Safety by Choice” banners might be an idea for others.