An Optimized and Reduced Chemical Kinetic Model for Hydrogen and Natural Gas Blends Combustion in Industrial Gas Turbines

Abstract

Natural gas is one of the common fuels that is used in gas turbines for power generation. Due to its interest in power generation and other applications, there are several chemical kinetic models available in the literature for natural gas. The power generation sector is moving toward decarbonization and there has been increased interest in replacing conventional fuels with fuels that produce less/zero carbon emissions like hydrogen. Pure hydrogen has a very wide flammability range and poses risks related to flashback and high thermal NOx production. Blending hydrogen with natural gas helps in having better control over the fuel properties. However, the literature lacks well-validated chemical kinetic models for the combustion of hydrogen blended natural gas for undilute mixtures at gas turbine-relevant conditions (8–16 bar). Hence, in this work, we develop a detailed chemical kinetic model for hydrogen-blended natural gas and validate it with a wide range of experimental data for both dilute and undilute mixtures relevant to gas turbine operating conditions. We outline the strengths and weaknesses of the current mechanism to aid future users of our chemical kinetic mechanism. The detailed chemical kinetic mechanism is then reduced to two smaller versions (60 species and 44 species mechanisms) without significant loss in accuracy using Directed Relation Graph with Error Propagation (DRGEP). To improve the prediction for pure hydrogen combustion while retaining all other predictive capabilities, an optimization is carried out for the most sensitive reactions for hydrogen combustion. The resultant mechanism can predict a wide range of experimental results with the least cumulative error.