Gas

A great location, a fish-friendly cooling system, and the extent of environmental remediation needed to permit it distinguish this repowering project on the Hudson River just south of the New York State capital.

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Three years ago, an article in POWER described how Cheng Power Systems, by modifying the combustors of several popular gas turbines, had used steam injection to lower the units’ NOx output to about 5 ppm—but some models had substantial CO levels without combustor modifications. Since then, the company has developed new combustor nozzles that recently […]

Duct burners use supplementary firing to increase the heat energy of a gas turbine’s exhaust, making it possible to increase the output of a downstream heat-recovery steam generator (HRSG). Early systems of the 1960s took a conventional approach to burner design. The exhaust of the turbine was directed into a windbox and then into a […]

In late February, the largest gas turbine ever manufactured by GE Energy at its Belfort plant in France began a 30-day journey by land and sea that will take it to a new power plant in Spain. The Frame 9FB gas turbine—which is also the first built completely in Belfort—was loaded onto a special, wide-load […]

Increased cycling of combined-cycle plants has made precise control of attemperator spray water within heat-recovery steam generators more important if damage to their hardware and piping is to be avoided. Complicating the issue is the industry’s still-limited experience with cycling and the fact that demands on the attemperator and turbine bypass of cycled plants are more stringent than those on baseloaded units.

Nearly five years ago, a major IPP began standardizing steam cycle chemistry feed, control, and monitoring across its combined-cycle fleet. This article discusses the steps taken, the costs incurred, and the technical and financial benefits achieved. Although the project focused on non-cogeneration plants, the findings detailed below are broadly applicable to other kinds of plants. However, the specific implementations (especially of the chemistry standards) described may have to be modified slightly for application to cogen plants.

Designers of heat-recovery steam generators are using computational fluid dynamics software as one tool to reveal the invisible forces affecting the flow over, under, around, and through structures such as inlet ducts, distribution grids, and guide vanes.

The jury is still out on the economic and technical feasibility of burning gasified coal to generate electricity. Gasification technology has yet to be proven on a utility scale, especially with Powder River Basin coal as the feedstock. And on the generation side, there are more questions than answers about the capital cost and availability of integrated gasification combined-cycle (IGCC) plants. But with natural gas prices high and rising, it’s definitely worth examining whether it would be economically and technically feasible to convert the existing U.S. fleet of gas-fired combined-cycle plants to burn gasified coal.

Operating a combined-cycle power plant profitably is no walk in the park, even under ideal conditions. But the extreme conditions at the Beluga Power Plant—from isolation to volcanoes—challenge its staff every day in ways that operators in the lower 48 can only imagine.

Global Monitor

With U.S. combined-cycle plants increasingly being cycled—rather than being run continuously, as they were designed to do—owner/operators worry that units expected to last two or three decades may survive only a few years without an expensive overhaul. Cycling takes as much of a toll on heat-recovery steam generators as it does on gas turbines. Whether you’re procuring a new HRSG or adapting an existing one for cycling service, robust design features should be what you’re looking for.

The U.S. power generation industry is changing at warp speed, via regulatory changes, consolidation, mergers, and sales of assets at yard-sale prices. New players have entered the market and become major players overnight, while several mainstays have gone bankrupt. Though many of the latter blamed high gas prices for their woes, well-diversified merchants enjoyed a record year. Whatever changes are in store for the business of combined-cycle generation, you can be sure that innovations in plant design and O&M such as those described in this special section will keep pace with them.

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GE Energy’s latest "first" is in Turkey, where the Frame 6C gas turbine-generator—a younger cousin of the popular Frame 6B—has made its commercial debut. The turnkey 130-MW combined-cycle plant, called the GE206C, comprises two 40-MW Frame 6Cs, one GE steam turbine-generator, two heat-recovery steam generators, and a distributed control system. The gas-fired plant (Figure 1), […]

  The U.S. needs to add 600 to 800 billion cubic feet (Bcf) of natural gas storage capacity ASAP. Independent storage providers (ISPs) are the entities best equipped to build this needed infrastructure, but they continue to be restrained by anachronistic regulatory policies. The Federal Energy Regulatory Commission’s (FERC’s) December 2005 rule-making to modify its […]

Munich-based Siemens Power Generation (PG) recently finished building the 384-MW combined-cycle Tahaddart Power Plant in the city of the same name in Morocco (Figure 2). The turnkey project, which is about 20 miles south of Tangier, was completed in 25 months. The plant’s natural gas fuel comes through a new, 8-mile-long spur that connects to […]