2013 Combined Cycle Users Group: Issue #2

Early experience with fast-start combined cycles positive say plant personnel
The Combined Cycle Users Group (CCUG) has been closely following the development of a series of large generating plants designed for fast-start/fast-ramp service since the organization's first meeting in San Antonio three years ago. What sets these new combined cycles apart from others in the fleet are heat-recovery steam generators equipped with HP sections that permit operating flexibility not possible with conventional drum-type HRSGs. The ability to bring a unit into service quickly can significantly reduce fuel consumption and emissions of NOx, CO, and VOCs normally associated with startups. There are similar benefits for faster shutdowns as well. more
Safety is a state of mind and way of life

How safe is "safe"? Is any work process or personal pursuit ever safe enough? Obviously, nothing is or can be 100% safe, but the elimination of controllable accidents in the workplace and home is a big step in the right direction. Dr Robert Mayfield, chairman of the Combined Cycle Users Group and plant manager of the 3 x 1 Tenaska Virginia Generating Station, is an effervescent champion of safety. more

Stator connection-ring vibration KOs F-class, H2-cooled generator

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A user received the blue ribbon from the editors in the intense, four-hour electrical session at the CCUG for a brief, but compelling account of a massive failure in an 11-month-old, F-class, hydrogen-cooled generator at a combined-cycle plant. One can find hundreds of articles about the virtues of visual inspection of generators and the perils of dusting or greasing, but this was a rare public account of winding vibration in extremis. Such sharing of knowledge among owner/operators is critical to the success of user groups. more

Drum chemistry, amines, sample panels, use of recycled water, EDI top discussion points in CCUG water treatment session

The CCUG is perhaps the only organization serving gas-turbine owner/ operators that covers water treatment for the entire plant-that is, steam/water chemistry, cooling water, makeup and demineralization systems, and wastewater. Dan Sampson, a senior technical consultant for WorleyParsons with more than two decades of experience in powerplant water treatment, conducted a clinic on the subject. Sampson is highly regarded by the membership for his commanding presence and insightful and interactive presentations. more

What are the life limits for your condenser sparger?
The value of a presentation is not related to the length of time the speaker stands at the podium. An example of an alert that left many attendees at the 2013 CCUG meeting with mouths agape concerned the failure of a condenser sparger pipe at an F-class combined-cycle plant. The speaker set the stage: "Most combined cycles are designed to operate in steam bypass mode during startups to allow the steam turbine and other equipment to warm up at a controlled rate-usually with the gas turbine at part load. Many condensers are 'designed' or 'rated' for full-flow steam-turbine bypass." more
Dual-fuel plant operates in simple- or combined-cycle mode
The CCUG takes an integrated approach to the design, operation, and maintenance of simple- and combined-cycle plants, setting it apart from the traditional user organizations serving gas-turbine owner/operators, which focus on a specific piece of equipment-the Frame 6 engine, for example. Several short presentations and open discussion concerning the idiosyncrasies of operating a dual-fuel combined cycle also permitted for simple-cycle service illustrates the point. more
Lessons learned from CCGT projects

CCUG programs are dominated by presentations made by plant owners and operators; there were a dozen at the two-day 2013 meeting, held at the Arizona Biltmore, September 3-5. One focused on lessons learned on recent plant construction projects-always a topic of great interest and one that fuels meaningful discussion. The following are over a dozen points made by the user presenting:

- TA cost overruns can eat your lunch.

- Fuel-gas heater: Intended versus actual service.

- What's the best contractual arrangement with an EPC? more


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