A Proven Engine Optimizer for the Aeroderivative Industry: Challenges and Solutions
Authors: Demougeot Nicolas , van den Hout Franklin , Grobbe Danny , Wang Wenping 
Published: November 2022

Premixed combustion systems are the ticket for low pollutant emissions, but they are also inherently unstable. With the introduction of the new operating requirements for Power Generation Gas Turbines, initiated by renewable energy sources, premixed combustion systems require not only revamping but also non-stop condition monitoring and tuning. Severe noise (pressure pulsations) within the combustor can lead to significant damage and accelerated wear. Also, the introduction of Hydrogen itself as an Energy Storage Solution and a potential fuel for use in Gas Turbines has complicated this process even more.

Manually tuning these engines used to be only a once-or-twice-a-year seasonal activity and always leads to the introduction of ample margins to safeguard against normal deviations over time from season and engine degradation. This has, unfortunately, been limiting the potential improvements in overall emission levels as well as gas turbine efficiency.

Such manual tuning has now slowly evolved into fully automated real time tuning versions such as our AutoTune system (AT) and they have been already in use in the Heavy-Duty Gas Turbine Industry for over fifteen years. Thomassen has started transferring this knowledge and experience also to the fleet of Aeroderivative Gas Turbines such as the LM6000PD DLE and the LM2500 DLE.

To accomplish the transfer of the existing AT Technology, a dynamic model of the LM6000PD DLE, was further enhanced to include the full DLE combustion system and process. This model can be run from within the Woodward GAP software. The closed loop entailed that the dynamic model included an emissions and combustion dynamics model. The values would be sent to the AT box, whereafter the AT box could send corrective actions via Modbus back to the LM6000PD Simulator/controller after processing.

A textbook perfect simulator was born in which the actions and reactions of both AT and Aeroderivative Engine could be analyzed, monitored, and optimized simultaneously. With the results of some actual manual field mappings of LM6000PD’s the dynamic model was perfected and the original Autotune system could be revamped and tested for use with Aeroderivative Industrial Engines.

Challenges existed in the integration of the Autotune actions and permissives into the current LM6000PD WoodWard controller (GAP) It had to be done in such a way that this additional logic remains supportive in the optimization process of engine Emissions and Combustion Dynamics, closely representing actual manual seasonal mapping but without intruding or overriding the core engine control and protection of the engine itself. AT always acts as a slave while the core engine control is always the master.

Autotune for LM-DLE has been successfully tested on the closed loop simulator and some of the new AT functionality has also been validated on a real engine. The results show promising and realistic improvements in In-Window emissions of NOX and CO as well as Cross-Window Gas Turbine Efficiency improvements. The efficiency improvement option is the most important part and is further detailed in this paper.

Full demonstration and validation of the new AT system is now being prepared on a real LM6000PD DLE engine (demonstrator). The next step is to perform simulator trials on a further adopted and enhanced dynamic model of the LM2500 DLE.