The LM2500+G4 is an advanced variant of the LM2500+ aeroderivative gas turbine, designed to provide increased output and thermal efficiency through a set of targeted design upgrades. It retains the core architecture of the LM2500+ but introduces changes to the flow path that increase overall engine performance.

The primary difference between the LM2500+G4 and the LM2500+ is the increased flow capacity in the high-pressure (HP) compressor, HP turbine, and low-pressure turbine. These modifications raise the overall pressure ratio from 23.6 to 24.2, resulting in higher thermal efficiency and greater mass flow. The design changes are relatively limited, focusing mainly on minor geometry adjustments to blades and vanes to accommodate the increased flow.

In the high-pressure turbine, the G4 version includes improved blade cooling and upgraded materials. These changes enable the turbine to handle higher temperatures, contributing to both improved performance and component durability. To maintain proper rotor thrust balance with the updated flow path, the effective area of the compressor discharge pressure seal was also adjusted.

In terms of operational performance, the LM2500+G4 offers measurable improvements over the LM2500+ across a variety of ambient conditions. For example, it delivers approximately 11% more power in cold conditions and 12% more in hot conditions (running data to -50 deg F and start data to –40 deg F). In combined-cycle mode, the G4 variant is expected to provide a power increase of 8.5% and a heat rate improvement of 0.75% compared to the LM2500+.

The LM2500+G4 supports two power turbine configurations:

• A six-stage, low-speed power turbine, typically used for power generation applications with a nominal speed of 3600 rpm.
• A two-stage High-Speed Power Turbine (HSPT), used for mechanical drive applications, designed for a nominal speed of 6100 rpm, with an operating range from 3050 to 6400 rpm.

Both configurations support operation over a cubic load curve, which allows the turbine to match power output with varying mechanical loads — a feature especially useful in pipeline compression and similar variable-load industrial applications.

The 3” Globe-Style Gas Metering Valve is designed to deliver accurate and consistent fuel control in industrial gas turbines, including both Dry Low Emissions (DLE) and Single Annular Combustor (SAC) engine types. This valve ensures that the correct amount of gas fuel is metered into the engine based on real-time operating conditions—essential for achieving stable combustion, optimal turbine performance, and reduced emissions.

With an accuracy of ±3% of flow point and a full-stroke response time of 175 milliseconds, it supports precise adjustments to the fuel-to-air ratio, even under fluctuating load conditions. This level of performance is critical for maintaining turbine efficiency, lowering NOx and CO emissions, and supporting regulatory compliance.

The globe-style design allows for smooth fuel flow control, making it ideal for high-capacity, high-pressure turbine applications, such as those found in the oil and gas industry. Built to withstand extreme temperatures and pressures, the valve is available with certifications such as ATEX Zone 1 and 2, PED, UL, and NEC Class 1, ensuring safe operation in hazardous environments.

This metering valve supports modern turbine control systems and is part of a generation of components that prioritize long-term reliability, reduced maintenance needs, and consistent field performance.

The 2″ Gas Metering Valve is designed to precisely control the flow of gas fuel in aero-derivative gas turbines, including the LM2500. By adjusting fuel delivery based on operating conditions, it maintains the optimal fuel-to-air ratio essential for safe, efficient, and reliable turbine operation.

Fuel metering valves act as the throttle control for gas turbines. Since turbines generate power by burning fuel mixed with compressed air, accurate regulation of this mixture directly impacts power output, efficiency, and emissions such as nitrogen oxides (NOx) and carbon monoxide (CO).

This valve delivers exceptional accuracy within ±1% of the flow point, ensuring consistent fuel delivery and optimal combustion. It is built to perform reliably in demanding environments and meets safety standards including ATEX, PED, and UL, certifying it for use in hazardous and extreme conditions.

The fuel metering valve is a two-inch right-angle style valve commonly used on aero-derivative turbines. It integrates easily into existing systems without requiring hydraulic or electrical changes. With millions of hours of proven field performance, it offers dependable, precise fuel control that enhances turbine efficiency and reduces fuel consumption.

The Gas Check Valve is a unidirectional valve used in LM2500 gas turbine systems to prevent the reverse flow of combustion gases into critical fuel and oil lines. Its primary function is to maintain the correct flow direction, ensuring that gases only travel toward the combustion chamber and not back into upstream components, where reverse flow could cause damage, safety risks, or system inefficiencies.

This check valve is engineered to operate under the high-pressure and high-temperature conditions typical of industrial gas turbine environments. It serves as a passive safety component, requiring no external power to function, and contributes to the overall reliability and integrity of the turbine system.

Commonly found in aero-derivative gas turbines used in oil and gas applications, the check valve is essential for maintaining proper system performance. Its inclusion in the turbine’s gas path helps ensure safe operation by minimizing the risk of combustion gas contamination in auxiliary systems.

The Single Annular Combustor (SAC) version of the LM2500+G4 is designed for oil and gas applications that prioritize consistent performance, fuel flexibility, and emissions control—such as LNG facilities, gas processing plants, and pipeline compression, both onshore and offshore.

What makes the SAC version different is its simpler combustor design compared to dual annular or premix types. The SAC uses a through-flow, venturi swirler to ensure an even temperature profile at the turbine inlet, helping extend hot section life. It features individually replaceable fuel nozzles, a durable machined-ring liner, and a thermal barrier coating for better resistance to high temperatures and corrosion. This design supports both dry operation (with higher emissions) and water or steam injection to reduce NOx when needed—making it adaptable to site-specific emission regulations.

The LM2500+G4 SAC builds on the proven LM2500+ design, with approximately 10% more power. This gain comes from increased airflow, improved internal cooling, and material upgrades—while keeping the same number of compressor and turbine stages. The 17-stage high-pressure axial compressor and the basic engine layout remain unchanged, making it easy to maintain and service.

The engine can run on a wide range of liquid and gas fuels, allowing flexibility in remote or supply-constrained locations. It achieves up to 40% thermal efficiency in simple cycle mode. Water-injected operation enables NOx emissions as low as 25 ppm (gas) and 42 ppm (liquid).

In short, the LM2500+G4 SAC is well-suited for high-power mechanical drive and power generation in harsh or remote oil and gas environments, offering a balance of power output, fuel versatility, and emissions control.