New turbine-compressor combination delivers highest thermal efficiency

The G4 is the 4th generation of the popular LM2500 and combines an enhanced aeroderivative gas generator with a two-stage, High Speed Power Turbine (HSPT). It is ideal for marine and industrial applications requiring high power output at high temperature conditions. The first unit is scheduled for delivery in late 2006.

The two-stage turbine module is designed to achieve efficiencies greater than 40%, the highest thermal efficiency available in this power range. Operating at a high speed of 6100 rpm, the power turbine is capable of directly driving a compressor without the need for a gear in most oil and gas applications.

The new unit will achieve a 10% power increase over its predecessor and is capable of even higher power as temperatures rise (+20% power @ 120°F). Its ISO power starts at 34 MW, offering higher power than other options in the market, in both ISO and off ISO conditions.

For the DLE version, NOx and CO emissions at 15% O2 are 25 ppmvd in the 100-75% load range – it also features a fuel gas control with five valves instead of three, enabling more accurate combustion tuning. Dual Fuel and Dual Fuel DLE will also be available in the near future.

Key features

• +20% power @ 120°F
• IGV redesign to increase flow
• HPC/HPT and TMF life analysis
• DLE emission improvements to maintain 25 ppm
• Increased HPT flow function
• Dry Low Emission (DLE) technology
• Increased flow function
• Strengthened blade material from IN738 to GTD IIIDS
• Availability and gas flexibility in upstream applications

* Natural Gas Fuel, zero Losses

Maximum upgrade flexibility

In order to optimize the new unit’s appeal as an affordable upgrade, our designers focused on delivering the power increase without making significant changes to the footprint or package design. All the core components remain the same, ensuring the same durability customers have come to rely on through the years.

Similar to the PGT25+, the new G4 machine offers the flexibility to operate on a range of fuels including natural gas, various gas mixtures and liquid fuel. We are also providing a technical services package including a safe-area installation design, customizations to meet specific customer requirements, and installation services for difficult environments such as offshore platforms.

Design information

• 17-stage axial compressor; pressure ratio 21.5:1
• Annular combustion chamber (30 fuel nozzles)
• Two-stage gas generator turbine
• Two-stage high speed power turbine (6,100 RPM)
• Gas generator, power turbine, and auxiliary system are mounted on a single base plate
• Integrated enclosure and base plate for easy maintenance
• Standard configuration: 21 by 12 by 13 ft (6.5 by 3.6 by 3.9 m); weighs 38 tons

The PGT25+G4 offers greater availability and gas flexibility for upstream applications. With its greater output, it also offers a better dollars-to-kilowatt ratio than other machines in its class.

For more information, please contact:

Jeremy Barnes
jeremy.barnes@ge.com

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