CCJ Archives: 3Q 2006

Compressor issues dominate discussion at annual conference

The 7F Gas Turbine User’s Group consistently conducts a superior annual conference. Three things stand out when reviewing meeting notes:

  • User involvement. The 7F is the largest frame user group, with more than 700 active members. Attendance at this year’s conference— nearly 250 user delegates, including more than 50 first-timers— was more than double that of the next largest frame meeting in 2006. more

Generators, controls lead presentation, discussion topics at annual meeting

Gabe Fleck’s easy demeanor and keen sense of what’s important for operating and maintaining gas-turbinebased generating facilities to the highest standards have helped rekindle the spirit of the 501D5/D5A Users. Attendance at the annual meeting June 11-15 in Memphis tied the alltime high established in 2005. Were it not for several last-minute cancellations, a new record would have been established. more

CTOTF expands, refocuses services to better serve users

Chairman John Lovelace and the Leadership Commi t tee of the Combustion Turbine Operations Task Force are rapidly moving forward with an ambitious plan to expand and refocus the organization’s services to maximize CTOTF’s benefit to the user community. more

Balanced program of user-only discussion forums and presentations by owner/operators and outside experts focuses on member O&M concerns

Frame 6 gas turbines (GTs) began generating kilowatt- hours in 1978. Since that time, nearly a thousand engines have been installed worldwide. Design features have evolved significantly over the years—two different models of the 6A and seven of the popular 6B— to accommodate evolving market needs, such as increased generating capability and lower emissions. more

Intense, interactive program covering major issues defines annual meeting

The V fleet in the Americas is not very large—fewer than 200 units by one unofficial count. It is characterized by several engine models and several owner/operators that are true “fans” of the machine—for want of a better term. By way of example, Conective Energy has a dozen V84.2s just at its Hay Road Power Complex in Delaware and Bethlehem Commerce Plant in Pennsylvania. more

Cost-effective repairs, life extension dominate discussions on ageing fleet

Hats off to Federico Kitzberger, chairman of the W251 Users Group, for developing from his office in Argentina, a top-notch meeting in Canada that included a robust technical program and valuable shop tours. The conference was held at the Sheraton Hamilton Hotel, Hamilton, Ont, May 16-19. Recall that Kitzberger took over the reins of the small group from Procter & Gamble’s Chris Moshner after the 251 meeting in December 2004; no conference was held in 2005. more

Timely borescope inspection prevents turbine damage

It wouldn’t be difficult to convince yourself that a robust MS5001P gas turbine (GT) averaging two fired starts per month and 40 fired hours per year over its 30-year lifetime doesn’t require much—if any— attention by the maintenance staff. However, that would be an inappropriate decision. more

Don’t forget the cooling tower

During major outages, plant personnel typically focus on the gas and steam turbines, whose shafts produce marketable product—the kilowatt-hours, the juice, the ‘trons. But, as the Second Law of Thermodynamics reveals, only a portion of the heat released by combustion of fuel can be converted to shaft work. The rest must be rejected to an energy sink at a lower temperature. In your competitive zeal for short, low-cost outages, do not neglect the system handling heat rejection. more

Planning and executing your 100,000-hr overhaul

By Marty Magby, Turbine Generator Maintenance Inc

The 100,000-hr overhaul of your gas turbine/generator (GT) typically occurs during the second of what the OEMs refer to as a “major inspection.” That’s appropriate, because the 100,000-hr inspection is indeed a major event. more

Key steps in inspecting, reconditioning generator rotors

Generators have a reputation for being so reliable that resource-challenged plant O&M staffs are inclined to focus their attention on gas turbines (GTs), heat-recovery steam generators, critical-service valves, and other equipment where problems are expected. But this strategy may not be in your best interest; it is important to give generators the minimal attention they typically require. more

Advanced repair techniques prolong hot-section component life

The repair of gas-turbine (GT) hot-gas-path (HGP) components— turbine blades, vanes, and combustor parts—has developed into a billion-dollar business. The reason plant owner/operators are opting for repair, rather than replacement of these critical components is simple: cost savings. Regardless of how extensive the repair procedures, and whether the potential replacement is provided by the original equipment manufacturer (OEM) or an independent shop, the cost of a repair typically will not exceed onethird of the cost of a replacement. more

Replacement of damaged lower IGVs with rotor in place saves IMPA a million

Proper operation of compressor inlet guide vanes (IGVs) is critical for reliable startups and for achieving maximum output from your gas turbine (GT). The importance of periodic inspection and operation cannot be overstated. Keep in mind that IGVs need occasional service: Any foreign material that gets by the trash screen can hit them; they can suffer ice-related damage under certain weather conditions, and water carryover into the bellmouth area from improperly located/designed air inlet louvers and/or poorly designed wet-type inlet-air cooling or wet-compression systems can attack critical parts. more

Assess the condition of your oils prior to the outage

Oil analysis is one of the most commonly applied predictive-maintenance technologies in today’s combined-cycle/cogen plant. For good reason: The technology can provide operators with early indication of abnormal wear, corrosion, or contamination occurring in vital equipment. That’s becoming even more important as turbines are built with longer and more massive shafts, and are operating under greater loads and at more

Gas-turbine valve sticking . . . the plot thickens

By Greg Livingstone and Jon Prescott, EPT Inc, and Dave Wooton, Wooton Consulting

Lubricant varnish is the primary cause of valve sticking/seizing in the hydraulic circuits of gas turbines (GTs). Because valve sticking often leads to starting problems and turbine trips, lubricant varnish has been one of the hottest topics at recent user group meetings. It also has been a frequent subject of technical letters by OEM engineers, conference presentations by lubricant professionals, webinars by oil suppliers, and so on. more

Machinery-health monitoring helps plants achieve financial goals

By Ned Endress, RoMaDyn

Machinery-health monitoring (MHM) systems continuously record and analyze turbine vibration data (see sidebar). They take raw data from vibration sensors and other process-related indications and convert it to actionable information about machinery condition—thereby enabling better asset management. In today’s merchant power business, high plant availability is critical to success and the continuous assessment of machine condition provided by MHM is critical to achieving demanding performance goals. more

Monitoring the service life of HRSGs

By Peter Rop, NEM bv

For many years, it has been common practice to employ a robust, service-life monitoring system on a combined-cycle/cogeneration plant’s most valuable turbomachinery: the gas turbines (GTs) and steam turbines (STs). To date, such monitoring systems typically have not been installed on the plant’s heat-recovery steam generators (HRSGs). more

Case study provides valuable perspective for your first GT rotor overhaul

After only a few years of experience, most gas-turbine (GT) users become familiar with the repair of hot-gas-path components, because these parts—the turbine blades (buckets), vanes (nozzles), and combustors— require maintenance at frequent intervals. Users typically are less familiar with the repair of GT rotors, because they usually operate for 100,000 hours or more with little attention required. more

Lifecycle planning for your DCS

Lifecycle planning for your DCS

By Mitch Cochran, Process Control Solutions LLC

The advent of the distributed control system (DCS) in the 1980s brought powerplant control into the digital age, combined the formerly separate functions of control and data acquisition, and enabled process data to be integrated with enterprise-wide business-management data. In the 1990s, DCS suppliers further enhanced their systems, moving away from proprietary hardware and software, and toward more inter-operable, standards-based networks. Net result: Today’s DCS is a reliable, user-friendly product that dominates the controls sector of the electric-power industry. more

How to prevent corrosion and deposition, and maintain steam purity, in combined-cycle/cogen plants

By Irvin J Cotton, Arthur Freedman Associates Inc, and John Obermaier, Deltak LLC

The objectives of water treatment in heat-recovery steam generators (HRSGs) are the same as they are in all boilers: more