Targeting Full-Hydrogen Operation on Industrial-Scale Gas Turbines: Impact of Unconventional Fuels on Turbine Module Performance and Aeromechanics

Abstract

With the trend to full decarbonization, a full-hydrogen economy development is a key industrial objective. Gas turbines, currently one of the cleanest fossil fuel-based power generation solutions, provide reliable and on-demand power. The introduction of hydrogen into the fuel mix of existing gas turbines represents a solution with great potential to provide low-carbon or even carbon-free energy. High-hydrogen-content fuels, however, challenge the efficient operation of the gas turbine expander, as crucial aspects such as increased flowrate, different gas properties, and temperature operating range may affect performance and structural integrity. To evaluate the impact of this conversion, a numerical investigation of five cases with increasing percentages of hydrogen in the fuel was carried out for an industrial four-stage gas turbine module. The variation of turbine inlet temperature distribution from the combustion chamber was considered, to assess the impact of the unconventional fuel on the well-known aeromechanical behavior of the last stage blades. Variations in capacity, efficiency, power, and potential limits due to aeroelasticity were evaluated, identifying the most relevant differences with respect to the full-methane case. All these analyses confirm the possibility of employing high-hydrogen fuel operation in a current gas turbine without the need of a further redesign while maintaining acceptable performance levels.