CTOTF launches bulletin board, keyword-searchable database to serve all GT users

Perhaps the headline should have said something about the real content of this article— money-saving O&M ideas culled from the technical presentations and discussions that took place at the Spring Turbine Forum of the Combustion Turbine Operations Task Force (CTOTF), last April, in Chattanooga. But CTOTF’s recent investment in a new online bulletin board and keywordsearchable database to serve the entire gas-turbine (GT) user community is sure to have far more long-term positive impact on the industry and deserves top billing—in the minds of the editors at least.

Effective technical communication has three legs: print, online, face-to-face. Absent one leg, like the proverbial stool, can present challenges. Print is an effective and convenient method for delivering information in summary form to a broad audience; the Internet, although generally impersonal, enables quick communication 24/7 to help solve an immediate need, such as locating a part for an ongoing outage; periodic conferences and expos cement relationships among users thereby enabling effective networks of “go-to” colleagues when another viewpoint is necessary.

To make its Internet presence more effective, CTOTF launched last month a custom-designed bulletin board with features that go well beyond those incorporated into its previous interactive site. What sets CTOTF’s new offering apart from bulletin boards hosted by the modelspecific user groups is that it is available to employees of any company with an equity interest in or currently operating any type of gas turbine. This includes companies with GTs under construction or on firm order. The other bulletin boards, as the editors understand, are accessible only by owner/operators of the specific machines supported by the groups sponsoring the Websites.

Chairman John Lovelace, a consulting engineer for Arizona Public Service Co (APS), Phoenix, says that CTOTF’s new site (http://forums.ctotf. org/login.asp) also hosts a keyword-searchable database of documents of value to the entire GT-based powerplant community—a knowledge warehouse that will continue to grow over time. The reference material already available includes presentations from CTOTF meetings, articles on gas turbines published in the COMBINED CYCLE Journal, and other timely documents.

Access to the bulletin board and archive are available at no cost to users, stresses Lovelace. It’s part of CTOTF’s commitment to enable transparent communications among GT owner/operators, he adds. Lovelace invites all GT users to apply for membership at the URL above. The review process for registration typically takes a couple of days.

The new communications vehicle was developed by Michael Elmo of Goose Creek Systems Inc, Indian Trail, NC. Elmo has extensive experience in the development and implementation of computerbased systems. In nearly 20 years with the Electric Power Research Institute’s Nondestructive Evaluation and Combustion Turbine Centers, he was principal investigator or a major participant on many projects supported by the generation industry to help end users make better decisions. One example: The computeroriented retaining-ring eddy-current test (CORRECT) system for condition analysis of 18Mn-5Cr generator retaining rings.

Organizational changes

CTOTF is not only expanding the scope of its services to the industry, it’s expanding the scope of the organization as well. Lovelace announced in July the formation of a ZLD (zero liquid discharge) Roundtable to help plant managers and staff sort through the wide range of problems surfacing with these systems. Many problems are caused by regulations written without a full understanding of how ZLD works and what its limitations are when hooked up to the back end of a powerplant that has to serve the grid reliably and in real time.

Long-term industry veterans may remember the ZLD systems of yesteryear— those installed in several large steam plants in the West in the early to mid 1980s. While some of the equipment in today’s offerings is the same as that in the early systems, recent advancements in membrane technologies and far more demanding regulations regarding the handling of chemicals and of system upsets and liquid discharges have created a cornucopia of new challenges.

ZLD systems certainly are not going away, at least not soon. More and more powerplants will be required to have them. One illustration of what many consider overkill: The state of California has dictated the use of ZLD on peaking turbines recently installed by at least one municipality, this to deal with the relatively small liquid waste streams created by treating the cooling water for evaporative coolers, lube-oil coolers, etc, and the production of high-quality poweraugmentation water.

1. The CTOTF advantage

The Combustion Turbine Operations Task Force (CTOTF) develops content-rich meetings serving many publics. In sharp contrast to other gas-turbine user groups, it addresses issues on virtually all engine models— aeroderivative and frame—produced by the major manufacturers. CTOTF is the ideal forum for someone who is time- or budget-constrained and responsible for more than one type of machine.

The group’s semi-annual meetings revolve around a series of roundtables. Each focuses on the engines produced by a given frame OEM (original equipment manufacturer). Content of these sessions can vary substantially from meeting to meeting. For example, in the spring the Siemens Roundtable might address a topic common to the entire 501 series of machines, V engines, the W251, etc—such as experience in upgrading control systems to the new T3000. In the fall, it may zero-in on one or more problems associated with a specific machine. By contrast, programs for most of the model-specific user groups start at the compressor and work through the machine addressing issues component by component.

CTOTF also has two special forums for aero users (one general and one dedicated to the FT8), as well as a generic roundtable that covers specific topics of interest to most in attendance—such as generators—and a legacy roundtable that focuses on equipment purchased prior to about 1985.

Each roundtable has a user chairman and vice chairman with plant operations and maintenance (O&M) experience to help plan the program for their session and to guide the interactive discussion.

The CTOTF Program Committee, headed by Jeff Lee of Arizona Public Service Co, assists in identifying topics of interest to the group. These ideas are funneled through the Leadership Committee, which consists of the chairman, vice chairman, the roundtable chairs and vice chairs, and the group/conference coordinator.

One of the challenges to an all-volunteer organization is maintaining day-to-day communications to address user needs in timely fashion. CTOTF satisfies this vital requirement through the “always available” Group/Conference Coordinator Wickey Elmo of Goose Creek Systems Inc, Indian Trail, NC. Elmo sits on the Leadership Committee and has access to the latest information concerning group activities, including opportunities for participation in CTOTF conferences and exhibitions. If your question can’t be answered by visiting www.ctotf.org, contact Elmo at wickelmo@ctotf.com or 704-753-5377.

2. Herb Allen honored for his quiet, productive leadership

CTOTF’s second chairman, Herb Allen, attended the Spring Turbine Forum in Chattanooga and accepted an award from his colleagues for a lifetime of contributions to the gas-turbine-based powerplant community—in particular his steady hand and the keen sense of direction and purpose required to lead the organization during some challenging years, 1984-1991.

John Lovelace, the current and third chairman of CTOTF, reflected on “the formative years” of the group, now 31 years old. He went back to “the beginning,” 1975, when a group of GT operators met to discuss problems they were having with GE Frame 7 machines. Charlie Knauf, Lovelace said, was the first chairman, a position he held until losing his “user” status by leaving Long Island Lighting Co’s GT technical group in 1984 for a position at the Electric Power Research Institute.

When Allen, a Florida Power Corp (now Progress Energy) employee, became chairman, the group was affiliated with the Edison Electric Institute, reporting to the Steam and Combustion Turbine Subcommittee of the EEI Prime Movers Committee. That relationship lasted for 16 years, ending with the reorganization of EEI in 1995.

Lovelace, who led the transition from an EEI-sponsored organization to CTOTF’s current independent status, continued speaking about Allen. “Herb,” he said, “was a quality guy, a person who facilitated interchange, quiet by nature, but a confident ‘force’ when it came to getting things done.”

“Back in ‘those days,’” Lovelace continued, “the chairman did everything: He had to persuade a utility to host the meeting, he had to get the speakers, he had to make the hotel arrangements. Herb did it all and did it well. He was a team player, believing CTOTF was an organization by the members, for the members. It was never about one man and his agenda.”

Allen had to relinquish his position as CTOTF chairman when he retired from Florida Power in 1991. He spent several years thereafter as a consultant; his area of specialty was maintenance procedures.

Scott Takinen, plant manager, West Phoenix Generating Station, and David Brunson, plant manager, Redhawk Generating Station (two 2 × 1 F-class power blocks), are the chair and co-chair, respectively, of the ZLD Roundtable. Both plants have ZLD systems and both men are well versed in the challenges these systems present to managers of merchant facilities. Takinen, the first PM at Redhawk, and Brunson, were at Redhawk from groundbreaking. It’s relatively safe to say “they’ve seen it all.”

Changing faces. Since the Spring Turbine Forum, business pressures have forced the resignation of Vice Chairman David Jeffery of Reliant Energy; Benton PUD’s Bob Hunter, vice chair of the FT8 Users Roundtable, resigned his post because of a job change. Bob Kirn of TVA, chair of the GE Roundtable, was selected to fill Jeffery’s position; TVA’s John Gamble fills Kirn’s vacant seat.Hunter’s CTOTF position remains open at this time.

Jeffery and Hunter, both wellliked, always approachable, and strong proponent’s of CTOTF’s mission, will be missed. Hunter recently moved his family back East, having accepted a position as customer service engineer with Pratt & Whitney Power Systems where he is attached to the ancillary engineering group. Hunter’s primary responsibilities include working with customers to resolve problems, new design implementation, upgrades, and root-cause analysis of FT8 issues.

Plenary session, the first morning

Chairman Lovelace welcomed delegates to Spring Turbine Forum, introduced them to the Leadership Committee, and then reviewed the organization’s guidelines of conduct for all in attendance. This included avoiding discussion of bidders’ lists and pricing, treating as confidential all material discussed at roundtable sessions, etc.

Ron Hall, general manager

of combustion turbines and distributed resources for Tennessee Valley Authority, then extended his welcome on behalf of the host utility.Hall’s short presentation on life in the Tennessee Valley before and after the creation of TVA, and visuals on the company’s meteoric development, offered an engaging perspective on the incomparable value of electricity to a developing economy.

Most industry veterans in attendance probably were not surprised by TVA’s total generating capability of 30,644 MW (record peak demand stands at 31,924 MW), or by the facts that coal-fired powerplants represent just under half that total and hydro another 17%. After all, it was hydro that launched the company and coal was an inexpensive energy source readily available to electrify at least parts of the seven states the giant utility serves. Most participants also recalled TVA’s nuclear presence, now totaling nearly 6000 MW.

But the company’s investment in nearly 5000 MW of GT capacity was a surprise to many. There are only a handful of utilities in the country with more total generating capability than TVA has in GTs alone. A thumbnail sketch of the company’s gas-turbine assets follows.All machines are peaking units equipped for dual-fuel service:

  • Johnsonville Fossil Plant, New Johnsonville, Tenn—16 GE 7Bs and four GE 7EAs, total capacity of 1498 MW.
  • Gallatin Fossil Plant, Gallatin, Tenn—four W501B4s and four GE 7EAs, total capacity of 785 MW.
  • Colbert Fossil Plant, Tuscumbia, Ala—eight GE 7Bs, total capacity of 486 MW.
  • Kemper Combustion Turbine Plant, DeKalb, Miss—four GE 7EAs, total capacity of 401 MW.
  • Lagoon Creek Power Plant , Brownsville, Tenn—12 GE 7EAs, total capacity of 1206 MW.
  • Allen Fossil Plant, Memphis, Tenn—16 GE 5Ns and 4 GE 7Bs, total capacity of 610 MW.

Herb Allen. Following Group/ Conference Coordinator Wickey Elmo’s presentation on highlights of the 2006 spring forum—which included, for newcomers, a review of the meeting’s organization by roundtables (refer to Sidebar 1)—Lovelace presented Herb Allen, the second CTOTF chairman (1984-1991), the organization’s lifetime achievement award (Sidebar 2).

Akber Pasha, technical director (thermal), Vogt Power International Inc, Louisville, then made the first of the meeting’s technical presentations. His timely topic: “All You Want to Know about Grade 91 Material”—a tall order for a 45-min presentation.

Pasha, one of the leading experts in the American boiler industry on P91/T91 material and a frequent participant in international meetings on the subject, offered a primer of value to every owner/operator of heat-recovery steam generators (HRSGs). The first quarter of his presentation reviewed the metallurgy so critical to understanding why P91/ T91 must be handled properly from manufacture through erection and during maintenance activities throughout the HRSG’s life cycle. The bottom line: There’s little, if any, margin for error when working with P91/T91; mistakes routinely lead to the premature failure of pressure parts.

Structural changes in P91/T91 that adversely impact its beneficial properties can occur from improper mechanical work, over- and undertempering in terms of duration or temperature level, and other reasons. Pasha noted that thick components routinely are under-tempered; thinner ones, over-tempered. Also noteworthy: Improper heat-treatment during the fabrication can result in a P91/T91 component having a variable metallurgy, depending on the time and temperature of exposure and the cooling rate.

Sensitivity to both shop- and fieldconstruction procedures that often are less standard and consistent than claimed, means owner/operators must write ever tighter specifications and be especially vigilant in monitoring the manufacture and erection of critical HRSG components. A review of failure mechanisms, including a look at the types of cracks that occur and where they are most likely to be found, came next in Pasha’s presentation.

Proper design of individual components and the HRSG proper also is critical to success when working with P91/T91. Pasha had a couple of slides illustrating why life-cycle calculations of creep and fatigue of this material differ from more traditional steels used in boilers.

For a more in-depth presentation on the subject, access these articles from the COMBINED CYCLE Journal at www.psimedia.info/ ccjarchives.htm: “Special workshop explores P91/T91 issues, impending ASME Code changes,” Third Quarter 2005, p 3; “Growing experience with P91/T91 forcing essential code changes,” First Quarter 2005, p 8.

Water washing. Charlie Knauf, CTOTF’s first chairman (1975-1984), was remembered by Elmo for saying “there has never been a CTOTF meeting where water washing of GT compressors was not discussed.” The 2006 Spring Turbine Forum was no exception.

Hugh Sales’ presentation on the value of compressor washing for maintaining GT performance sounds better each time the price of fuel goes up. The operative word here is “maintaining.” Remember that you cannot increase efficiency by water washing, only gain back most of what was lost to the accumulation of dirt and other deposits on compressor blades and vanes.

Sales, a VP at Houstonbased Gas Turbine Efficiency (GTE, gtefficiency.com) is a pro in every sense of the word. He knows his subject well and has some compelling data to support the saving that he claims a first-rate washing system can deliver. Sales began with a tutorial on water washing and finished with a successful case history from a plant in the refinery corridor near Houston that is equipped with two F-class GTs in cogeneration service. Let’s look at the second part first to illustrate just how much a wash water system can impact a plant’s financial statement.

Both units at this Gulf Coast facility were equipped with inlet fogging and wash water systems supplied by the OEM when the machines were installed in fall 2001. One wash water system was changed out in March 2005 to GTE’s offering to permit an accurate comparison test.

Replacing the original was a relatively simple job: Mechanics unscrewed the OEM offline wash nozzles and installed in their place new GTE nozzles for both offline and online washing. The nozzles were connected in series with high-pressure stainless-steel wrapped flex hose which, in turn, was hooked up to existing OEM plumbing. Then the OEM’s pump skid was removed and the GTE skid moved into its place and connected to the OEM plumbing. New skid was wired and the supply plumbing attached.

Results of the test as reported by Sales: The new online washing arrangement doubled the heat-rate improvement of the OEM’s system; degradation between offline washes slowed from a rate of more than 2 MW/month to less than 0.5; number of offline washes was reduced from six per year to three.

The annual saving of $2.7 million, assuming site operations remain as before, totals this way: $1 million in reduced fuel cost attributed to the heat-rate improvement, $1.6 million attributed to the sharp reduction in performance degradation, and a $100,000 saving in offline washing expense. For some plants in the merchant power business that could double the facility’s annual profit—all things being equal, of course.

While a dramatic saving in O&M expense captures the imagination of everyone with bottom-line responsibility, what Sales had to say about the process variables most impacting washing efficiency was good information to bring back to the plant for further evaluation. This background may prove valuable in formulating questions for prospective suppliers should you be involved in the purchase of a wash system.

The optimization variables for a water wash system that you should be familiar with are these:

Water temperature. Water that’s too cold is conducive to blade temperature variation, loss of cleaning efficacy, and the increased need for chemicals. Water that’s too hot leads to increased early vaporization and loss of fluid penetration. Plus, it presents a safety risk to operators. The “just right” temperature, Sales said, was about 140F.

Water pressure is optimum within the range of 750 to 1400 psig. The designer’s goal is to accelerate water to approximately air-flow speed, not to increase blade impact. Water pressure within the range cited provides maximum dispersion across IGVs and R0 stage, maximum penetration into the compressor core, minimizes the waste of water and chemicals (if used), and ensures penetration of the air-flow boundary layer on blades and vanes.

Droplet size. Sales said this was the most critical variable in terms of cleaning penetration and erosion. If droplet size is too small—less than 40 microns according to Sales— water never reaches the blade surface, it merely follows air flow and no washing is accomplished. If it is too large—over 180 microns—the droplets may damage blades and inertial forces that throw water to the outer case may occur.

Water volume. The optimized water volume ranges from four to six minutes of water flow at approximately 40 gpm. The actual number depends on the size of the turbine.

Nozzle design and placement. Spray pattern for a nozzle should be engineered after considering the other variables being optimized. If true optimization is accomplished, Sales said, you only need one set of nozzles to accomplish both online and offline washes. Also, you will require far fewer nozzles (perhaps only a third as many) than others might say you need, he continued. Typical retrofit applications, Sales added, normally call for replacing existing OEM offline nozzles with those capable of both online and offline washing.

Fire prevention/ protection a hot topic at Generic Roundtable

Reliant Energy’s Jack Borsch and KeySpan Energy’s Bill Nawrath, the chair and co-chair, respectively, of the Generic Roundtable are hands-on engineers with a keen sense of what’s important to run a powerplant efficiently, reliably, safely, and within budget. They share a broad O&M perspective, which is evident by the diversity of subject matter covered in their session. The Generic Roundtable always gets high marks from attendees.

At the Spring Turbine Forum, much discussion focused on fire prevention and protection. One user presented on root-cause failure analysis of an aero-engine fire. Unit was operating on liquid fuel when the fire was detected shortly after startup. The automatic foam system discharged immediately and the fuel supply was shut down. Fire department responded within minutes.

Investigators concluded that the fire was initiated by a fuel leak onto the hot engine casing; lube oil, ignited by the primary fire, was a secondary source of “fuel.” Foam system most likely performed as intended but was unable to extinguish a fire of the size experienced.

A note in the foam-system manual is instructive for all with these types of systems: Fires caused by leaks of either gaseous or liquid fuels under pressure are difficult to extinguish and can continue to burn within a space completely filled with high-expansion foam. An additional fire suppression system is a possible solution.

Another user talked about the importance of proper operator intervention when a fire is detected. He said that at one plant he was familiar with a maintenance team reported a fire to the control room and the operator, unaware of the cause, hit the E-stop immediately.While this may sound like the proper action, in this case it wasn’t. Fire was in the fuel system and the operator’s action killed lube oil flow to the bearings, damaging them unnecessarily.

The takeaway from this experience is continuous training and drilling.Everyone forgets procedures that have not been exercised for a long periods of time. Periodic review of what actions to take and when is critical to safety and high availability.

Ivan Insua, an engineer with Salt River Project (SRP) delivered another insightful presentation on the subject of fire. It occurred last spring at the company’s 600-MW, 2 × 1 F-class combined- cycle at Desert Basin Generating Station in Casa Grande, Ariz.

Background: Work associated with the major inspection of Unit 2 was nearly complete and new media was being installed in the evaporative cooler; all generating units were offline and many systems still were de-energized; no fuel gas was onsite; a contractor was welding on the exterior wall of the air-inlet house.

A one-word description of the fire: spectacular (Fig 1). The high elevation of the air inlet house and the wideopen and flat desert terrain surrounding the plant contributed to the fire’s visibility. Fuel was bone-dry evaporative media and particulate filters; source of ignition was heat associated with grinding and welding.

The fire “took hold fast,” said Insua, and the speed with which it occurred serves as a reminder of the large amount of highly combustible material (when dry) in the filter house. All alarms worked and the 911 call was made immediately. Plant operating procedures specify that plant personnel fight garbagecan- size fires, the fire department to handle anything larger than that.

The immediate thought of several engineers listening to Insua was to turn on water to the evaporative media. Good idea; however, the cooler sumps were dry and the PVC piping had melted. Insua continued. He discussed how the plant conducted regular drills with the fire department (FD), how procedures were followed successfully to insure that MSDSs (material safety data sheets) and a current list of visitors actually onsite were available when the FD arrived, etc.

Fly in the ointment—there always seems to be one—said Insua was that the 911 operator mistakenly dispatched the emergency call to county, not to the Casa Grande FD that the plant conducted its drills with (plant is within city limits). Instead of help arriving within a few minutes, it took about half an hour for fire trucks to reach the plant. Message here is that you can’t check enough things often enough when personnel safety is at risk. Insua suggested that attendees verify that their alarms and 911 calls reach the proper emergency units upon returning to their respective plants.

Aftermath: No one was hurt. Everything upstream of the silencers was ruined and had to be replaced. There was no damage to the GT and no debris or water from the fire-fighting team reached the inlet scroll. Good emergency procedures and proper response by plant and contractor personnel contained the damage as intended.

In closing, Insua suggested regular orientation and training programs to ensure all employees know their plant well. This includes the dangers present, where emergency/safety equipment and protective clothing are stored, where fire hydrants are located, order of calls to make in an emergency, etc.

Cooling- tower inspection.

Most plant personnel probably think they’re maintaining their cooling towers properly, but the only way to tell for sure is with thorough, periodic inspections. You may very well find something disturbing. This is especially critical for mechanical-draft towers serving plants in cycling service.Wet/dry cycles can play havoc with wood members as one user showed in a revealing presentation. You may also learn that it’s necessary to change operating procedures to accommodate cycling without excessive wear and tear on tower members.

Here’s a short description of the type of damage that can occur based on the case history discussed. On a load-critical day, a roving operator identified one cell in the mechanical- draft tower as partially collapsed.Water was drained from the 54-in.- diam fiberglass distribution header at the top of the tower (Fig 2) and part of the line was removed, exposing some of the damage (Fig 3). Inspectors found that at least three posts/ columns had failed (Fig 4), as well as four beams; there were numerous lateral- restraint failures. Members also failed at connections (Fig 5).

The decision on whether to repair or rebuild was relatively easy to make. The rebuild quote was half that of the new. Plus there was no operational penalty—that is, for a one-cell rebuild, most of the tower remains in service continuously and the plant is derated only minimally.

Ageing of the transformer fleet is a growing concern among plant operators, with major repairs both costly and time-consuming. Equipment failures have forced outages or plant deratings of up to a year in some cases. Craig Stiegemeier of ABB Inc, St. Louis, closed out the Generic Roundtable with a short clinic on transformer preventive maintenance that also covered diagnostic techniques for assessing transformer health.

GE Roundtable addresses many user concerns

TVA’s Bob Kirn, who chaired the GE Roundtable through the Spring Turbine Forum, said “GE Day” focused primarily on technical issues associated with the Frame 7FA as well as with steam turbines installed in combined-cycle systems. Updates on TILs (technical information letters) and lively Q&A ensured that many user concerns were addressed satisfactorily.

Featured presentation topics by the more than one dozen GE experts in attendance included generator and GT reliability, GT uprates and services, BOP (balance of plant) solutions, and control systems. An interesting fact from the services presentation is that the company now has contractual services agreements (CSAs) at 624 plant sites worldwide that cover more than 2000 turbines.

A segment of the program was reserved for the OEM’s recently announced Evolution Compressor, which GE says offers significant performance improvements in both output and heat rate when retrofitted on Frame 7B through 7EA and 9E machines. The redesign team made use of leading-edge aerodynamic software for on-wing applications and other advanced engineering tools, and incorporated lessons learned from fleet experience since the original B/ Es were installed, to ensure an efficient and reliable product.

The Evolution Compressor is the first phase of the company’s multiphase performance-enhancement Evolution Program. It retains all current parts and rotor-life estimates and can accommodate future firingtemperature increases. The first retrofit will be done at Midway Sunset Cogeneration Co’s plant located in the oilfields near Taft, Calif.

Compressor stator-vane shim loss. After the GE program ended, Vice-Chair Larry Rose, an engineer in Dominion Energy’s CT Operations Group, addressed the GE Roundtable on his company’s recent experience with compressor stator-vane shim loss on both Frame 7F/FA and Frame 7EA machines.

Subject is of interest to owner and operators of these engines for several reasons, including:

  • Performance suffers when shims come loose and protrude into the flow path.
  • If shim migration continues, the resulting flow disturbance can produce a strong once-per-revolution stimulus at the tips of downstream rotor blades. High-cycle fatigue damage in neighboring blades is possible under such conditions.
  • In the extreme, when sufficient wear occurs at shim tabs—often referred to as “ears”—because of blade movement and the sharp corners in the casing groove, shims, or parts of them, can release into flow stream and cause FOD (foreign object damage) downstream.

Rose’s presentation focused on Rows S0-S4 of the 7F/FA (Fig 6) and Rows S1-S4 of the 7EA. Stator vanes in these rows are of the ring-segment design (Fig 7). Vanes in later stages are individually mounted—each on its own square base. The vane rings are forged of steel and then broached to make the dovetail slots; then they are saw-cut into six segments of various lengths.

Shims—either 40 or 80 mils thick— are inserted between ring segments where needed to make up for saw kerf material loss (Fig 8). The tabs that extend from the shims fit in the casing hooks and are supposed to be retained by them. Note that shims cannot be used at horizontal joints.Fig 9 shows typical shim assembly installed.

Borescope photo, Fig 10, shows shim protruding into the flow stream. Reason is evident in Fig 11: An ear is missing. When a shim migrates into the flow stream, part of it can break off and go downstream. Or the entire shim can work its way loose and liberate. In either case, downstream damage to vanes and blades is virtually impossible to avoid (Fig 12). In this case, the compressor case was opened immediately to conduct blend repairs.

Failure mechanism. With the problem well defined, Rose discussed several possible failure mechanisms. First he presented the OEM’s explanation:

  • Shims can become bound when ring segments expand faster than the case during starts.
  • Shim fretting can happen during vane vibratory responses from the dynamic nature of air flowing over the vanes.
  • Shims float in the ring-segment hooks and when clamped during startup, may contact the casing hooks before the ring segments thereby overloading the shim tabs. Investigative work done by engineers at Dominion revealed that the shims are clamped in place by the rough serrations at the ends of the ring segments (think Vice Grips here). The starts-based thermal ratcheting of shims pushes them radially inward, overloading the shim tab. Rose said that high-cycle fatigue also is at work, but evidence of this is most prevalent in segments for Rows S3 and S4.

The information Rose presented urged caution once shims are found out of place either during a borescope examination or by other visual means. Experience indicates that loose shims will continue to move outward, which very definitely is not a good thing. For example, one 7FA that went commercial in 2004 had fewer than 175 starts by spring 2005 when one shim was found protruding 1/8 in. into the flow stream. In fall 2005 and 150 starts later, the shim was 3/4 in. into the flow stream and susceptible to cracking from aerodynamic stimulation. Rose’s recommendation: If you find a shim beginning to migrate into the flow stream reinspect within the next 100 starts.

What to do when you find a protruding  shim? There almost always is no easy solution. Rose related experience on one 7FA where shim repair was the critical path of a six-day outage. Only 18 months after COD (commercial operating date) vane segments were difficult to remove; those in Row S0 in the lowerhalf of the casing the most difficult. Some segments were destroyed during removal. However, work was done under warranty.

Pinning said fast, effective for securing shims to vane segments

Pinning is a proven fastening technique, one used frequently for securing shims to squarebase stator vanes beyond Row S4 of Frame 7 compressors. A patent is pending on the procedure developed by Rodger Anderson (randerson@ drs-pt.com, 978-353-5318), manager of GT technology for DRS-Power Technology Inc, Schenectady, NY.

Advantage of the method over alternatives— such as bolting—is that it is fast as well as effective, says Anderson. He offers this example to illustrate the point: Pinning of 1234 square-based vanes in a Frame 7 compressor (all vanes in Rows S5 through S16) was accomplished within 14 hours. When job started, tip rock in 70% of the vanes exceeded the OEM spec; no tip rock on any vane at job’s end. For more background, refer to 7EA Users Group report in COMBINED CYCLE Journal, Fourth Quarter 2004, p 59; available at www.psimedia.info/ccjarchives.htm.

There are several fixes to consider, he continued. Extraction allows you to postpone repair from an unplanned event to a planned one. Rose said that Dominion’s experience in pulling shims from Rows S0 and S1 has been mixed. In one case—and only one—workers were able to remove a protruding shim with Vice Grips. Personnel developed a “shim puller” and that was only marginally successful, because there is so little room to maneuver. Experienced mechanics have extreme difficulty working above Row S1 on both 7F/FAs and 7EAs.

In terms of problem correction, there seems to be four viable solutions at present:

  • OEM bolting fix (considered an interim fix). Remove segments, drill holes through new shim and into the end of the segment, tap holes in the segment, bolt shims in place (Fig 13). Counterbore mating segment to accommodate bolt heads.
  • Weld shims to segments on difficult- to-remove segments rather than destroy the segments (Fig 14). Consider removing a couple of Row S0 segments to get working room and be sure to protect neighboring parts.
  • Weld additional material to the ends of carbon-steel vane-ring segments and machine to ensure proper fit-up.
  • Pin shims to vane segments using a technique developed by DRS-Power Technology Inc, Schenectady, NY (sidebar).

Finally, Rose suggested that users consider eliminating, when convenient, 40-mil-thick shims everywhere in the compressor since they would be most prone to failure.

GT rotors, generators, controls lead parade of subjects at Alstom Roundtable

The Alstom Roundtable can be likened to the marines: not many in numbers, but top engineering talent among both users and presenters. A successful meeting requires knowledgeable leadership and Chairman Bob McCue of the Midland Cogeneration Venture LP (MCV) and Vice Chair Ed Sundheim of Con Edison Development Inc certainly bring that to the table. Between them, they have decades of experience with Alstom equipment and know well what constitutes a meaningful program for users.

Of course, that’s only half the equation. It often is said “content is king,” and that is developed and delivered, in large measure, by a collaborative OEM. Formal user presentations and solid discussion periods led by McCue and Sundheim balanced out the program.

Subject matter ran the gamut, related McCue. Many questions were generated, many action items listed for follow-up by Alstom. Here’s a sample of the discussion topics, illustrating the wide range of subjects:

  • Overspeed testing.
  • How to make transition welds on inner combustor liners.
  • Facilitating the inspection of compressors for pitting that can be so severe as to require blade replacement. McCue mentioned Alstom’s solution implemented at MCV— the installation of a borescope port to do this without lifting the lid.
  • Converting hydraulic fluid to Fyrquel , a phosphate ester, because it is fire-resistant and personnel safety is a major concern.
  • How to make a suitable screen for the low-NOx EV burners used in silo combustors that would protect hot-gas-path components from compressor debris.

Prepared presentations by Alstom were delivered by Paul Elkovich, VP of the GT service business unit in America, and Ron Cox, director of marketing for the US rotating service business. Elkovich opened the session by updating the group on fleet-wide operating data. He said that Alstom is seeing an uptick in overall capacity factor like other OEMs, probably because of lower reserve margins.Gas prices may be moderating growth somewhat, but there are few practical alternatives to more generation.

Elkovich’s then spoke in detail about the 11D/N rotor optimization program, which had been summarized at CTOTF’s Fall Turbine Forum in Banff last year. Next, he updated the group on low-cycle fatigue (LCF) cracking experiences with 11D/N rotors, which is caused primarily by heavy cycling. Elkovich explained that the susceptibility of the L-bore area of an 11D/N rotor to LCF crack initiation depends on the type of service.

Alstom has developed multiple solutions to address the cracking problem should it occur, he continued. One can be implemented onsite and will extend life by another 300 starts. A permanent shop-based fix, which can be accomplished in less than a month, requires welding and stress relief, but it will extend life by another 3000 starts. The third option is rotor reconditioning, which requires a new “hot section” with a cooling bore designed to exceed 4000 starts.

For a more in-depth discussion of L-groove cracking and repair methods, read “GT11N L-groove repair solutions from OEM optimized for duty cycle,” in the User Group Activities section of the COMBINED CYCLE Journal, First Quarter 2006, p 74; access at www.psimedia.info/ccjarchives.htm.

Elkovich then spoke about a second category of rotor ageing, high-temperature creep, and how it can restrict the life of welded rotors. Creep can impact all GT rotors, he said, regardless of the manufacturer. Rotors for the 11D/N series of machines do not readily accommodate creep measurement because of their characteristic tangential-entry blade roots. Rather, design calculations and fleet experience are used for predicting life.

The original design standard for 11D/N rotor lifetime was 100,000 EOH (equivalent operating hours). New design tools, backed up by field verification and service experience, have allowed Alstom to extend the lifetime to 130,000 EOH.

Elkovich explained that the company’s methodology for extending rotor life beyond 130,000 EOH is a “whack and weld” solution. The rotor is severed at the drum and a replacement section is inserted and welded using processes similar to those used to manufacture the original spindle.

Result is a new rotor in the critical “hot section.” Alstom routinely welds rotors for both its steam and gas turbines, and has applied the same technology to STs made by other OEMs, Elkovich said, adding that this type of repair/rehabilitation is common for the company and has been used on nearly 100 rotors.

Later, Elkovich updated users on the 11N lower combustor insert/ inner-liner collar cracking experiences and solutions. One of his slides showed Alstom’s updated inner-liner collar design, which uses a straight cylindrical transition, followed by a radius with a smooth surface finish.

Users unable to attend the Spring Turbine Forum who have an interest in learning more about the upgrades summarized above should contact Ron Cox directly (ron.cox@power. alstom.com).

Cox’s presentation was on a new repair procedure developed by Alstom for a generator stator condemned by the OEM. Its significance for users, beyond the technology employed, is that what might not have been repairable yesterday, may be repairable today. It behooves all plant managers to get a second opinion when the first one recommends the scrap heap.

Repair technologies are advancing rapidly. OEMs, and the thirdparty service providers that compete against them, are investing heavily in equipment and techniques for maintenance and repair that bring value to the user. Owner/operators of merchant plants, in particular, can improve their bottom lines significantly by taking advantage of the growing “can-do” attitude in the repair sector.

To learn more about the Alstom generator repair technique, refer to the Western Turbine Users report elsewhere in this issue and turn to the section “Generators a hot topic.”

Controls. Sundheim led a couple of chatty discussions in the controls area. One was on distributed control systems supplied by ABB and Alstom for what are now referred to as legacy machines. Another focused on replacements for the ABB Egatrol. This GT control system, which dates back 15 or more years, is not supported by Alstom and replacement cards are difficult to come by, according to users.

Alstom responded by saying that it continues to support these systems and has developed a whole new series of upgraded direct-replacement cards known as “Blue Line” for the ABB Egatrol cards. Blue Line cards offer higher processing speed and Ethernet compatibility (Fig 15). In a related development, Alstom recently introduced a faster CPU (central processing unit) for the ABB P-13 control system.

Talk during the controls portion of the session was mostly about the advantages that accrue from a control system upgrade to today’s open architecture: Easier to change settings, easier for technicians to recalibrate, fewer cards for the same results, etc.

FT8 Roundtable compresses much into busy day

Chairman Ray deBerge of AmerenUE and Vice Chair Bob Hunter of Benton PUD molded a balanced program that featured an outside speaker on fire protection, several user presentations, and OEM participation. As noted at the beginning of the CTOTF report, Hunter has since resigned his CTOTF position, having left the utility to join Pratt & Whitney Power Systems (PWPS).

There were two parts to Randy Sherry’s presentation on GT fire protection systems—one concerned with inspection, testing, and maintenance; the other, 2005 changes to NFPA-12, “Standard on Carbon Dioxide Extinguishing Systems,” and their impact on the industry.Sherry (rsherry@associatedfire.net, 402-733-2800) is affiliated with Associated Fire Protection, Omaha.

“Fortunately,” Sherry began, “fire protection equipment is seldom called upon to perform the job for which it was provided. However, when needed, it must perform flawlessly— often to keep a small problem from becoming a disaster.”

Ultimately, he continued, plant management is responsible for establishing and monitoring the inspection, testing, and preventive maintenance (ITPM) program required to ensure system functionality when required. The type and frequency of this work, Sherry suggested, can be modified to suit site-specific conditions, but such decisions should be based on a realistic risk/reliability analysis.

Next, he urged development of an action plan both to review and assess your current ITPM program and to identify and plan the implementation of upgrades to improve system reliability. Steps to success include these, said Sherry:

  • Review the recognized NFPA (National Fire Protection Assn) standards to see what they recommend for your powerplant. For example, NFPA-12 recommends that tank liquid level in low-pressure CO2 systems be inspected by plant personnel weekly. NFPA 12A for Halon systems recommends an annual inspection by contractor personnel of hose condition.
  • Develop site-specific criteria using the NFPA recommendations as a starting point. Modify as needed after conducting a sound risk/reliability analysis and reviewing regulatory/ insurance requirements.
  • Use plant personnel only for those ITPM activities that reasonably fit their experience and availability. Leave the rest to fire-protection contractors—especially work that requires special experience or tools. It’s plant management’s responsibility to see that there are no gaps between work being done by in-house and contractor manpower; be sure all elements of the program are addressed.
  • Provide management oversight/ supervision to verify that critical work is performed correctly and in a timely manner according to the guidelines developed.

CO2. Sherry’s review of NFPA-12 and the 2005 changes to that standard certainly made the CTOTF experience a very productive one for anyone at a plant with a CO2 extinguishing system. He reviewed the standard chapter by chapter explaining the changes. Most revisions were easy to grasp quickly and many were non-technical. For example, what signage must be placed where, signage style sheet (format, color, letter style, message panel lettering), etc.

There were three user O&M presentations. DPL Energy’s Dave Richardson presented the details of a procedure for replacing bolts on the turbine exit-vane positioning ring based on PWPS Service Bulletin (SB) 05M03; Hunter spoke about operator qualification and the development of a program that leads to a certificate for a given plant site; deBerge presented on the latest Windows XP-based server and HMI software upgrade offered by PWPS, which is used at one of the plants he manages.

“The upgrade has provided a more stable operating platform while addressing issues with the previous HMI and operating system,” deBerge noted. “Equally important is the expansion of our ability to analyze process events and structure operating data profiles to better understand our machines,” he continued.

The chairman also led a discussion on an installation of the OEM-recommended power-turbine thrust-balance active feedback retrofit (refer to SB 05M04). A follow-up report on the performance of this upgrade after the summer run season is slated for the Fall Turbine Forum at the end of August.

Pratt & Whitney. Jerry McCormick (jerry.mccormick@pw.utc.com) and Joe Updegraff from PWPS’s customer service group represented the OEM. McCormick began by updating the group on FT8 fleet status and reviewing service bulletins issued in the last year as well as recent revisions to technical manuals.Next, questions submitted by users ahead of the session were answered. Finally, a frank roundtable discussion addressed a broad range of topics based on both pre-submitted questions and follow-up inquiries— including the value of ORAP® (refer to the Western Turbine Users report in this issue for details), control upgrades, maintenance practices, and spare-parts availability.

Legacy Roundtable gains in stature

There are relatively few, if any, owners scrapping equipment that can still generate power. It may not operate often—some GTs fewer than 100 hours annually—but if the shaft still turns and on-going costs are within reason, it stands ready for service. As the saying goes, “You never know.” This philosophy translates to a growing inventory of so-called legacy machines—for the purposes of this discussion, GTs built 20 or more years ago.

Chairman Steve Hedge of NRG Texas and Vice Chair Eddie Mims of Colectric Partners are doing halfday sessions now, but it won’t be long before the information needs of users overwhelm the four hours of program availability. One reason is that owner/operators are unlikely to have low-hours machines covered by any form of OEM warranty. Plus, OEMs often have not maintained the expertise base they had for older machines because of marginal profitability at best.

The bottom line: Most owners have assumed full responsibility for O&M and overhaul of their older units, and meetings that address legacy issues, like the CTOTF, become more valuable as the years pass. The Legacy Roundtable is the ultimate self-help clinic for users charged with overhauling and refurbishing their equipment to as good as new, or better, at the lowest possible cost.

Bucket rock. The search for specialty, low-overhead service providers is a continuous process for owner/ operators of legacy machines. One such service provider, Paul Tucker, addressed the group on bucket rock in GE Frame 7 machines: why it occurs, damage it causes, and corrective action. One of the points he made was that severe bucket rock could allow the liberation of seal pins which, in turn, could cause severe damage to downstream buckets and nozzles.

History first: Tucker’s (txtbsolutions@ hotmail.com, 281-381-0218) resume describes in detail his more than three decades in the rotor repair business, including 21 years with GE and short stints at Preco Turbine & Compressor Services, Sermatech Technical Services, and Wood Group.He started two Houston-based companies in 2003: FIRST LLP (for First Independent Rotor Services of Texas), a consultancy, and Turbine Bolting Solutions LLP, a manufacturer of bolts and fasteners for a wide range of gas and steam turbines, and seal pins for Frame 7s.

Tucker’s primer on bucket rock began with its definition—the circumferential movement between any two or more buckets. The problem, most prevalent in machines that cycle, also has been found in base-load units.

Bucket rock usually is most severe in rotors with a history of operating for long periods at the 30-40 rpm typical of the OEM’s turning gear. What happens at this speed is that buckets move slightly in the wheel dovetail as they pass top and bottom dead center, wearing the softer wheel material.Wear loosens the blades even more. Blast cleaning is another reason for the loss of material in the wheel dovetail that causes bucket rock.

Tucker then described how best to measure bucket rock. He also provided users valuable background on the purpose of seal pins—they prevent hot gas from entering the dovetail cavity and overheating the bucket or the wheel—and compared the OEM’s pin to the one offered by Technical Bolting Solutions.

Options for reducing bucket rock concluded Tucker’s remarks. His solutions included these:

  • Reduce turning-gear run time.
  • Modify the torque converter to allow turning-gear operation at 60 to 80 rpm and restrict bucket movement.
  • Grind vertical seal-pin slots to accept pins of the largest diameter allowed by the OEM—0.180 in.
  • Metal spray the unloaded side of the wheel dovetails with nickel aluminide using the high-velocity oxygen fuel (HVOF) process.
  • Metal spray the unloaded side of the bucket dovetails. This may be easier than coating the wheel because buckets are far more portable. However, when buckets are refurbished or replaced, the coating must be repeated.
  • Replace turbine wheel. Major consideration for this option is its cost, which may be higher than expected if problems are identified when the rotor is destacked. Also, unless you change procedures for turning-gear operation, the new wheel also will wear.

Impact of NSR on maintenance. Chairman Hedge made a short presentation that alerted attendees to the shifting sands of New Source Review (NSR) and the problems an unsuspecting or misinformed plant manager could face. He began by reviewing the controversial history of NSR. The main impact of NSR, Hedge said, was directed at new plants until the mid 1990s when lawsuits were filed against several companies that operated coalfired units.

In brief, NSR is triggered when a new facility is built or an existing one is modified. Most of the controversy surrounding NSR—at least in the generation sector of the electric power industry—focuses on what constitutes a “modification.” Hedge said that NSR defines modification as a non-routine repair or replacement that results in a (1) physical change to the plant, or a change in its method of operation, and (2) an increase in emissions.

“But,” he asked, “what does ‘non-routine maintenance’ really mean?” That the activity is routine for the type of unit—replacing GT blades, for example? Or, that the maintenance is routine within the industry—such as replacing a turbine wheel? “Unfortunately,” Hedge continued, “different federal courts have ruled that ‘routine maintenance’ can mean either of those definitions.

Next, “What does an ‘increase in emissions’ really mean?” Emissions measured annually or hourly? He said that different courts have ruled for and against both alternatives when determining if an increase in emissions has occurred.

To avoid unnecessary headaches, Hedge suggested that NSR be a consideration when planning any major repair or replacement projects—particularly if capacity will increase. In wrapping up, he urged plant managers to contact their company environmental staff or an experienced environmental attorney before committing to any major maintenance or project.

TVA’s John Gamble, the new chairman of the GE Roundtable, was a valuable addition to the program, speaking on TVA’s legacy units and the problems that have surfaced in the last few years. The utility has 16 Frame 5Ns, 28 Frame 7Bs, and four W501B4s—a lot of legacy for sure.

Gamble first discussed compressor blade failures on the Frame 5s and 7s. Two units were heavily damaged in year 2000 when Row 0 AISI 403 stationary blades in each machine failed and liberated metal. Failure modes in both cases were high-cycle fatigue (HCF).

He said that GE also has performed analyses on AISI compressor blade failures on Frame 5s and 7s. The OEM’s work revealed that environmental characteristics change the sensitivity of AISI 403 to corrosion pit size and to HCF. The smallest surface flaw influences HCF crack initiation; the curve plotting loss of properties against environment is much steeper than originally thought. In addition to the obvious stress concentrations caused by pits, there is a reduction in the endurance limit of parts subjected to HCF.

Gamble also reviewed TVA’s experience with steam-turbine casing cracks, HCF in Type 403 stainless steel rotating blades, bucket rock and rotor disk wear, generator field failures, diaphragm deterioration, etc.

Aero Roundtable focuses on LM6000

The marquee presentation at the Aero Roundtable, chaired by Richard Rebori of PSEG Power, was on the LM6000. Jerry Babic, the GE contract performance manager for PSEG Power, conducted the session. He began by reviewing the operating history of the 600-engine fleet, which has accumulated more than 11-million service hours.

Babic ran through slide after slide of depot findings so users knew better what to look for when returning to their plants and what action to take if they found anything suspicious. A couple of examples:

  • Inlet gearbox; bevel gear wear; some wear generally is considered normal; inspect carefully at overhaul.
  • LPC shaft rub caused by contact with No. 1 air/oil seal; condition found only on seals predating Service Bulletin 148; implement SB 148 at exposure.

Technical programs underway at GE in support of the LM6000 focused on individual components—such as the LM6000-PD durable dome combustor being developed to address issues with the current combustor. Babic reviewed more than a dozen current programs, outlining objectives, summarizing progress thus far, and giving an expected availability date for each upgrade.

The O&M portion of the presentation reviewed the company’s Service Bulletin program, including its purpose and customer responsibilities.

Rotor cracking, compressor icing discussed at Siemens Roundtable

Ray Martens, plant manager, Klamath (Ore) Cogeneration Plant, chaired his first Siemens Roundtable, elected to the position after Mike Murphy of Puget Sound Energy Inc resigned.Vice chair is Paul Tegen of Cogentrix Energy Inc. Difficult to find two users with more knowledge of Siemens machines. Both are active in the 501F Users Group as well; Tegen is the chair of that organization and Martens is on the steering committee.

Program for the Siemens Roundtable in the spring is an abbreviated one—half a day. At the upcoming Fall Turbine Forum it will occupy the entire second day of the meeting as it traditionally does in the fall.

Mitsubishi Power Systems’ (Orlando) Michael Robson was the first speaker at this last session of the conference. His was a progress report on Mitsubishi’s growth in services capabilities for gas and steam turbines—including replacement parts, field work, shop repairs, etc. Robson also mentioned that the company recently was selected as the O&M contractor for a new 730-MW, 2 × 1 combined-cycle plant powered by M501Gs of its manufacture.

Salt River Project’s Ivan Insua, who had presented earlier in the conference before the Generic Roundtable on the company’s recent airinlet filter house fire at Desert Basin, returned to the podium to discuss rotor cracks found in one of the same facility’s 501FD2 rotors.

Martens moderated a lively discussion among attendees as to what might have been the root cause of the cracking. Among these: damaged honeycomb seal on Row 2 vanes that allowed hot gasses to enter the cavity area, rubbing, overheating, multiple trips and hot/cold starts during initial startup, etc.

Insua said that cracks in the scalloped regions of the Row 1 turbine disk (downstream side of the blades) were found after the rotor was removed from the machine for blade replacement/refurbishment. Note that the cracks were in an unloaded, low-stress area of the rotor and were confirmed by a proven NDE (nondestructive examination) method.

An OEM-supplied work crew blended the scalloped regions with hand tools to the satisfaction of both Siemens and the owner; no welding is permitted on this part of the rotor. No restrictions were placed on unit operation following the repair work. Recommendation was to inspect during the next regular hot-gas-path or major outage.

Inlet icing. Martens also had a formal presentation, his on Klamath’s forced outage caused by inlet icing. This is discussed in the 501F Users report—the first article in this issue.

Much of the open discussion centered on best practices and what users would do differently if they had influence over the design of a new combined-cycle plant. Interestingly, there was quite a difference of opinion on the optimal arrangement, with good arguments for 1 × 1 single-shaft, 2 × 1, and 3 × 1 facilities. Conclusion was that the nature of the power-purchase agreement would likely dictate the best arrangement.

Valves always are a high-profile component on Martens’ list of discussion points. The need for high-quality valves, especially those in severe service, is one of the few things that all users agree is an absolute necessity. That was confirmed once again at the Spring Turbine Forum.

Among the other points mentioned by attendees:

  • Set a time when the plant takes over the management of change for controls logic.
  • Provide overhead crane access for turbines, generators, and valves.
  • Limit OEM and contractors on the number of starts, trips, and hours allowed for commissioning. Several participants in the discussion said that they assumed responsibility for plants that had reached hours or starts limits for the first maintenance outage during commissioning.
  • Select the proper location for the cooling tower in relation to the GT inlets.
  • Have the historian operable before first fire.
  • Develop a collaborative relationship with the major OEMs as early as possible.
  • Plan punch-list and warranty administration carefully and thoroughly. Ccj

Tenaska, Emcali, MEAG honored with ‘heavy metal’ at awards luncheon sponsored by CTOTF

One of the biggest challenges facing owners and operators of gas-turbine-based powerplants, especially those in deregulated markets, is the need to continually improve the performance of their facilities—to increase revenues and decrease expenses. One component of this goal of “continual improvement” is Best Practices. These are the methods and procedures plants rely on to assure top performance on a predictable and repeatable basis.

The Best Practices Awards program launched in late 2004 by the COMBINED CYCLE Journal (CCJ) has as its primary objective the recognition of the valuable contributions made by plant staffs—and headquarters engineering and asset-management personnel as well—to ensure reliable, efficient, and safe operation of GT-based generating facilities.

Finalists for the 2006 awards in Management, O&M, and Safety gathered at the CTOTF’s Spring Turbine Forum for formal recognition. Details on each of the Best Practices submitted for judging can be found in the 1Q/2006 edition of the CCJ, p 9; access at www.psimedia. info/ccjarchives.htm.

Judging was by the CTOTF Leadership Committee, with scoring based on an evaluation of real and measurable achieved business value, complexity of the issue, operations staff involvement, degree of coordination across multiple groups, and duration of impact.

The Combustion Turbine Operations Task Force, the nation’s oldest GT user group, and the one with the broadest coverage in terms of manufacturers and models served, hosted the awards presentation during a special luncheon at its Spring Turbine Forum organized by Group/Conference Coordinator Wickey Elmo of Goose Creek Systems Inc. There are two levels of awards to recognize the achievements at individual plants: Best Practices and The Best of the Best, as determined by the judges’ scores.

Awards were presented in three categories: management, safety, and O&M. A tie for the top spot in the O&M category resulted in the presentation of four “The Best of the Best” awards. The “heavy metal” in the headline refers to the eight pounds that each of these plaques weighs.

Plants accepting the top awards were:

  •  Tenaska Virgina Generating Station for management.
  •  TermoEmcali Plant for safety.
  •  Central Alabama Generating Station and MEAG Wansley Unit 9 for O&M.

Announcement of the 2007 awards program is made elsewhere in this issue. Entries should not take more than about an hour to prepare and can be submitted to Bob Schwieger, editor and publisher, at any time on or before Dec 29, 2006. This is one way to get the recognition your plant, your staff, and you have earned by your collective resourcefulness. Please plan to participate.

Management awards

Tenaska Virgina Generating Station

Tenaska Inc

Accepted by Robert Mayfield, plant manager.

Community relations program has contributed significantly to the spirit de corps among plant staff and helped employees feel connected and valued within the area where they live and work.

Quachita Power LLC

Cogentrix Energy Inc

Accepted by Paul Tegen, chief CT engineer.

ACT (Achieving Compl iance Together) is a proactive environmental awareness program that demonstrates the plant’s dedication to achieving an industry-leading compliance record.

Safety awards

TermoEmcali Plant

Emcali; operated by North American Energy Services

Accepted by Rick Shackelford, plant manager, Green Country Energy.

Physical improvements to the sulfuric acid system significantly reduced the potential for injury caused by an accidental spill or leak. The acid has been handled without accident or incident.

MEAG Wansley Unit 9

Municipal Electric Authority of Georgia; operated by GE Contractual Services

Accepted by Eddie Mims, Colectric Partners.

A battery preventive maintenance program is critical to high unit reliability and availability. Safety and productivity have been improved by using a digital hydrometer and modified electrolyte fill system.

Central Alabama and Lindsay Hill Generating Stations

Tenaska Alabama I and II Partners, LP

Accepted by Robert Threlkeld, plant manager.

Safety program with a high level of employee involvement has been in place for more than a year without a recordable injury. Plant staff is more aware of safety now than previously and taking a more proactive role.

Whiting Clean Energy

NiSource Inc; operated by GE Contractual Services

Accepted by Doug Klar, operations manager.

Plant-wide ready access to an accurate list of chemicals onsite and to their respective material safety data sheets has facilitated documentation and management of hazardous materials in accordance with regulatory requirements.

O&M awards

Central Alabama Generating Station

Tenaska Alabama II Partners LP

Accepted by Robert Threlkeld, plant manager.

Process developed for reducing by 25% the time to start a cold steam turbine saves fuel and allows more even heat-up of the steam turbine prior to loading.

MEAG Wansley Unit 9

Municipal Electric Authority of Georgia;

operated by GE Contractual Services

Accepted by Eddie Mims, Colectric Partners.

Optimizing the plant’s automatic steam-turbine startup program enabled a more controlled use of allowable stress without exceeding the OEM’s design limits. Fuel cost saving was an added benefit.

Mustang Station

Denver City Energy Associates LP and GS Electric Generating Co-op Inc; operated by North American Energy Services

Accepted by Rick Shackelford, plant manager, Green Country Energy.

Process for early detection of FAC allows plant personnel to schedule replacement of affected pressure components during planned outages rather than during forced outages caused by pressure-part failures.

A recommissioning and upgrading of the steam-turbine hydraulic system eliminated varnish contamination and restored unit reliability and availability to expected levels.

Tenaska Virginia Generating Station

Tenaska Inc

Accepted by Robert Mayfield, plant manager.

Cost-benefit analysis allowed plant personnel to make technology investment decisions that increased plant efficiency while contributing to long-term O&M cost savings.

Jasper Generating Station

South Carolina Electric & Gas Co

Accepted by Don Belle, maintenance engineer.

A new approach to cooling-towerfan gearbox maintenance opts for long-lived synthetic oil and a portable oil cleanup unit to reduce power curtailments and waste disposal requirements while cutting the cost of gear overhauls and replacements.

Whiting Clean Energy

NiSource Inc; operated by GE Contractual Services

Accepted by Doug Klar, operations manager.

Application of GE’s Fast Ramp™ automatic generation control solution has increased revenue by allowing the plant to provide ancillary load-frequency regulation services to the grid.

A stack balloon has proved to be an easily deployable, cost-effective alternative to retrofitting a stack damper on cycling units in cold climes to maximize warm versus cold starts and prevent freeze-up.

Lindsay Hill Generating Station

Tenaska Alabama I Partners LP

Accepted by Robert Threlkeld, plant manager.

Better procedures and data trending, plus an aggressive leak-management program, substantially improved condenser performance. Benefits included lower fuel cost, higher plant output.