Transient Analysis of a Micro Gas Turbine With Fuel Composition Change

The aim of this study is to analyze the effect of fuel composition change on the performance and dynamic behavior of a T100 micro gas turbine. Fuel flexibility is a key asset of micro gas turbines and can support the energy transition when alternative fuels obtained from renewable energy sources are used. While the current research is mainly focusing on improving combustor performance, it is also required to investigate the effects of different fuel blends on the overall system. During transient operation, the use of fuels with a low LHV requires an increased fuel mass flow that can potentially reduce the compressor surge margin. Conversely, sudden composition changes of high LHV fuel can cause temperature peaks, detrimental for the turbine and recuperator life. In this paper, a validated transient model for the T100 machine has been used to simulate the injection of different fuels in the natural gas line (feeding the burner). Injection of hydrogen and ammonia, two promising carbon-free fuels, have been tested. A transient analysis was performed with this tool to monitor the main performance parameters with the aim to (i) verify compressor safe operations during different working conditions and (ii) to identify appropriate fuel composition change schedules to ensure Turbine Outlet Temperature values within an acceptable range, while keeping the original fuel control system.