Retrofit Kits for GE Aeroderivatives to Enhance Reliability, Increase Output, Reduce Emissions
ANAHEIM, CA -- Users of GE Marine & Industrial Engines' (M&I) aeroderivative gas turbines can enhance maintainability and reliability, increase power output and reduce emissions by applying GE's retrofit kits on existing LM units.Many of the retrofits offered can be tailored to specific customer needs and can be performed on-site to maximize availability while reducing maintenance costs. The kits are intended to help users:
- increase revenue by improving power output and increasing availability and reliability.
- reduce operating costs by increasing engine efficiency, enhancing parts life and reducing operating and maintenance costs
The popular LM2500 aeroderivative gas turbine is used to illustrate the types of retrofit packages offered by M&I:Maintainability/Reliability
LM2500: PE/PH Stage 1 high-pressure turbine nozzle with thermal barrier coating -- a thermal barrier coating is applied to the stage 1 high-pressure turbine nozzle of the LM2500 to enhance part life and repair. This enhancement can be incorporated as a set of individual nozzle segments or a modular assembly.Condition monitoring -- a variety of condition monitoring devices are available for the LM2500 to provide on-line remote monitoring of compressor performance to evaluate overall gas turbine performance. For example, a high-pressure compressor can be monitored with a variable stator vane position transducer and signal conditioner, as well as a T3 temperature sensor. Condition monitoring devices can be installed on-site during routine maintenance. Power Output/Efficiency Enhancement
Upgrade from PC to PE model -- the key factor in this upgrade is the replacement of the two-shank bladed high-pressure turbine with the improved technology based on single-shank blades. This enhanced air-cooled design uses special cored turbine blade castings and permits the turbine blade to operate at both lower temperatures and stress levels than the LM2500PC.Upgrade to PE steam model -- steam injection can be used in the standard LM2500PE model to enhance power output, improve thermal efficiency and suppress NOx . With the upgrade to the steam model, steam is injected into the compressor discharge port to increase power from 23.2 megawatts to 25 megawatts (ISO conditions). Upgrade to PE STIGô (Steam Injected Gas turbine) system -- the highest rating configuration for the LM2500PE uses the STIG system to enhance power output and suppress emissions. For the STIG upgrade, steam is injected into both combustor and compressor discharge pressure manifolds. Since the STIG system is capable of changing the steam injection rate rapidly, this type of configuration is ideal for cogeneration applications with varying process demands. In this case, the power increases from 23.2 megawatts to 28 megawatts, a 21% greater output. Upgrade from PE to PH STIG -- the PE configuration can be upgraded to the PH STIG model. This gas turbine is identical to the standard steam-injected LM2500PE STIG, but includes internal hardware modifications which increase high-pressure flow function by 2.2% and decrease low-pressure turbine flow function by 5%. These enhancements permit the injection of increased rates of steam to further improve power output and thermal efficiency.Emissions Reduction
Dry Low Emissions (DLE) system -- the DLE design provides very uniform mixture of fuel and air, a primary requirement in achieving low NOx levels. The DLE retrofit kit for the LM2500 is designed to meet emissions levels of 25 ppm NOx , 25 ppm CO and 5 ppm UHC. This system does not affect power output. Wet Low Emissions system -- users of an LM2500 without water or steam injection systems can choose from several wet retrofit options for existing units. Choices include gas/water, gas/steam, dual fuel/steam. Wet technology systems for the LM2500 are designed to achieve NOx levels as low as 15 ppm, depending on the type of fuel and the volume of water or steam injected. Retrofits can be performed by M&I, its OEMs or its authorized depots. M&I is currently developing other retrofit kits to meet end users' needs. Retrofit Orders
To date, M&I and its OEMs have secured the following orders for its retrofit kits: PEMEX/LM2500 uprate -- MTU Maintenance GmbH will install an uprate retrofit kit on an LM2500 compressor drive gas turbine owned by PEMEX, Mexico. This project marks the first sale of this type of retrofit kit for a compressor drive unit. The unit will be uprated from an LM2500PC to an LM2500PE model, and the unit's output will be enhanced to 31,200 shaft horsepower (shp) at ISO conditions from the present 27,500 shp rating. TBG Cogen/LM2500 emissions reduction -- two LM2500s at the TBG Cogen plant in Hicksville, NY, recently were retrofitted with new emissions reduction systems. This project, which was completed during a routine maintenance in April 1995, marked the first application of steam injection for NOx reduction on dual fuel LM2500s. The systems enable the gas turbines to meet New York state mandated RACT (reasonable available control technology) emissions requirement.