The rotor of Nuovo Pignone's new version of its PGT 10, designated PGT 10B, is set in a turbine shell at the company's Florence, Italy, manufacturing plant.Redesigned versions of a popular gas turbine have recently been ordered for a U.S. and an Italian company.
ARCO Alaska Inc., Anchorage, and Bioelettrica S.p.A., Pisa, have each ordered uprated versions of Nuovo Pignone's PGT 10 gas turbine, designated as PGT 10B.
New design
Nuovo Pignone says power output has been increased 10% to 11.6 mw in a design intended for industrial, cogeneration, and utility applications.The PGT 10B is also now available in a single-shaft version, whereas previously it had been available only as a two-shaft machine.
Nuovo Pignone is an Italian affiliate of General Electric Co. U.S.A. GE Power Systems bought majority ownership of Nuovo Pignone in 1994.
ARCO Alaska's order is for a two-shaft version for electric-power generation. It will be fueled primarily by natural gas but can burn a light liquid fuel.
In addition, ARCO Alaska ordered a 26.3-mw MS5001 turbogenerator, a centrifugal compressor driven by a 38,000-hp MS5002 gas turbine, and a centrifugal compressor driven by an electric motor.
Bioelettrica ordered a single-shaft PGT 10B for a power plant in Cascina, Italy. The company is an international consortium established to implement an "energy farm" demonstration as part of the Thermie program financed by the European Union.
As its primary fuel, the PGT 10B will use low-heating-value gas obtained from the gasification of biomass. Natural gas will be the startup and backup fuel, says Nuovo Pignone.
Development
The Italian supplier has said that, since introduction of the PGT 10 in 1988, more than 100 units have been sold, with approximately 80% being used for mechanical-drive applications and 20% for power generation. Customer demand for units driving electric generators, however, is increasing rapidly, says Pignone.Responding to demands for small gas turbines, Pignone designed a new axial compressor to augment the power output of the PGT 10. The new compressor has a 10% increase in mass airflow to achieve a correspondingly higher gas-turbine power output at the same firing temperature.
In addition, the design of the 17-stage axial flowpath compressor was simplified. The new design features an 11-stage axial compressor with wide-chord, low-aspect-ratio, high-strength blades.
The reduction in number of stages was achieved primarily through the flowpath redesign, says Pignone. The new compressor fits existing gas-turbine layout and requires only minor changes in the interfaces with other components and auxiliaries.
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