Thermodynamic and emission analysis of a hydrogen/methane fueled gas turbine

Abstract

The importance of hydrogen in the effort to decarbonize the power sector has grown immensely in recent years. Previous studies have investigated the effects of mixing hydrogen into natural gas for gas turbine combustors, but limited studies have examined the resulting effects hydrogen addition has on the entire system. In this work, a thermodynamic model of a gas turbine with combustion chemical kinetics integrated is created and the effects hydrogen addition (0–100 vol% addition) has on the system performance, emissions and combustion kinetics are analyzed. The maximum system performance is achieved when the maximum turbine inlet temperature is reached, and the resulting optimal fuel/air equivalence ratio is determined. As hydrogen is added to the fuel mixture, the optimal equivalence ratio shifts leaner, causing non-linearity in emissions and system performance at optimal conditions. An analysis of variance is conducted, and it is shown that isentropic efficiencies of the turbine and compressor influences the system performance the most out of any system parameter. While isentropic efficiencies of the turbine and compressor increase towards 100%, an operating regime where the optimal system efficiency cannot be achieved is discovered due to the lower flammability limit of the fuel being reached. This can be overcome by mixing hydrogen into the fuel.

Keywords

• Hydrogen combustion
• Gas turbine performance
• Thermodynamic modeling
• Fuel composition
• Parametric study