The GE LM2500+ DLE (Dry Low Emissions) is an upgraded, high-efficiency aeroderivative gas turbine derived from the CF6-6 aircraft engine. Introduced in the mid-1990s (with first applications appearing around 1997/1998), it provides higher power output compared to the standard LM2500 by increasing compressor airflow by 23% and increasing the firing temperature. The DLE technology allows the engine to burn natural gas with low NOx/CO emissions without requiring water or steam injection. [1, 2, 3, 4, 5]

Key Performance Characteristics

• Power Output: ~29–31 MW (ISO)
• Efficiency: ~38%–39% (ISO)
• Emissions: DLE technology maintains \(NO_{x}\) emissions at 25 ppmvd or lower when using natural gas fuel at full load.
• Operating Experience: The LM2500+DLE has accumulated over 2.4 million operating hours, often used in power generation, offshore platform, and pipeline compression applications. [1, 2, 3, 4, 5]

Key Milestones (1997–2019)

• 1997/1998: The first LM2500+ commercial application was delivered in late 1997 for a Statoil floating production vessel.
• 1998: A DLE-equipped LM2500+ was supplied to TSSI in Rheden, The Netherlands for an EDF project, with commercial operation beginning in late 1998.
• 2005: Projects like the Repower of an existing LM2500 SAC with DLE at a European customer (CVG) showed the transition path.
• 2011: GE introduced further upgrades, such as the LM2500+ G4 DLE, which enhanced power to over 35 MW.
• 2019 & Beyond: The LM2500+ continued to see upgrades, including the adoption of LM2500XPRESS modular packages for faster installation. [1, 2, 3, 4, 5]

Technical Upgrades (SAC to DLE)

The DLE system, often retrofitted to older SAC (Singular Annular Combustor) models, offers:

• Three-manifold fuel system: Replaces traditional fuel valves with electrically actuated DLE fuel metering valves.
• Improved Efficiency: Eliminating water injection increases thermal efficiency and reduces water consumption, making it ideal for regions with low water availability.
• Lower Flame Temperature: DLE lowers flame temperatures to reduce emissions throughout the operating range. [1, 2]

Applications

The LM2500+ DLE is used extensively in:

• Power Generation: Base load or peaking power (50/60 Hz).
• Oil & Gas: Offshore platform power and gas compression.
• Marine Propulsion: High-speed ferries and naval vessels (due to high power-to-weight ratio).