Session: 09-03 Gas Turbine Power Plant

Paper Number: 83026

83026 - A Proven Engine Optimizer for the Aeroderivative Industry: Challenges and Solutions 

The increasing use of renewable sources in the power industry is leading to new challenges for Gas Turbine (GT) operators. Very frequent start/stop cycles, large swings in power demand, increased loading/unloading rates and the need for peak loading or being able to park the engine at the lowest load possible are amongst those. Output limitations are getting stricter for pollutants such as NOx and CO, while CO₂, directly related to engine efficiency, is in the eye of the legislators.

Premix combustors are the ticket for low pollutant emissions but are also inherently unstable. Severe noise (pressure pulsations) within the combustor can lead to significant damage and accelerated wear. To counter that effect, manual combustion tuning, then automated versions, have been used in the GT frame (“Base Load”) industry for over fifteen years.

Aeroderivative GT engines are better suited, by design, to the new operating regimes observed in the industry. They have higher efficiency thanks to their high pressure ratio and associated higher firing temperature. However, to allow for that, the metal making the combustion chambers is protected underneath very brittle ceramic tiles. Acoustics (a.k.a. pulsations or combustion dynamics) are hence severely limited in amplitude. Manually tuning those engines leads to the use of ample margins to safeguard against normal deviations over time. This is unfortunately limiting potential improvements in overall emission levels but also efficiency.

Furthermore, aeroderivatives are using compressor air bleeds to control flame temperature in part load operation which is leading to significant losses in efficiency at those regimes. Optimization of bleed usage, while maintaining acoustics and emissions in check, shows significant gains in engine heat rate and results in additional revenue.

The engine control schemes are quite different between frame and aeroderivative engines, particularly the nozzle flame temperature governor. The design team faced significant challenges in order to incorporate an automated tuning system in the existing strict, hard to change and highly constrained engine code, those will be illustrated in this paper.

Additionally, bleed control is a sensitive subject with regards to compressor health and integrity. Once again, out of the box thinking and use of some of the essential bricks coming with an engine optimizer, such as algorithms for peak loading or to extend turndown, was key for success. This paper will expose those roadblocks and the solutions engineered.

Finally, extensive testing was done thanks to a state-of-the-art engine simulator developed specifically for the development program. The results from those tests will be illustrated and the benefits resulting from using a smart and universal automated tuning system will be demonstrated in terms of efficiency but also gains in emission and acoustics levels.

Although it started in the GT frame industry, it was only a question of time for automatic tuning technologies to be applied to aeroderivatives, furthering the operability envelope, reducing acoustics and emissions, and enabling important efficiency gains.

Presenting Author: Nicolas Demougeot Thomassen Energy

Presenting Author Biography: Nicolas is heading the Engineering department at Thomassen Energy and held positions in both the service and the development sides of the industry over his 20-year career.<br/>Nicolas’ design experience includes world class ultra-low pollutant combustors such as LECIII™ and FlameSheet™. He also led a talented team that designed the highly successful AutoTune control program, a generic, multiplatform optimizer. He took interest in Hydrogen over 25 years ago and has both personal and professional goals of helping with kick starting the Hydrogen economy.<br/>Nicolas owns an Engineer degree from the National Superior School of Mechanical and Aerospace Engineering in Poitiers, France and is undergoing Executive Master education with L’Ecole Polytechnique in Palaiseau, France. Nicolas owns several patents related to combustion and control design.

Authors:

Nicolas Demougeot Thomassen Energy
Franklin Van Den Hout Thomassen Energy
Danny Grobbe VBR Turbine Partners
Wenping Wang Power Systems Manufacturing