Study on Reduced Chemical Mechanisms of Ammonia/Methane Combustion under Gas Turbine Conditions

Abstract

As an alternative fuel and hydrogen carrier, ammonia is believed to have good potential for future power generation. To explore the feasibility of co-firing ammonia with methane, studies involving robust numerical analyses with detailed chemistry are required to progress toward industrial implementation. Therefore, the objective of this study is to determine a reduced mechanism for simulation studies of ammonia/methane combustion in practical gas turbine combustor conditions. First, five different-sized reduced mechanisms of the well-known Konnov’s mechanism were compared. The reduced mechanisms were tested for ignition delay time validation (zero dimensional) using ammonia/methane mixtures at high-pressure conditions relevant to gas turbine devices. Furthermore, the combustion products of ammonia/methane premixed laminar flames (one dimensional) were validated with the results from the full Konnov’s mechanism. Finally, computational fluid dynamics simulations of a turbulent flame (two dimensional) with all of the reduced mechanisms were performed under high-temperature and high-pressure conditions representative of industrial systems. Results show that several of the reduced mechanisms utilized performed reasonably well in combustion simulation studies under gas turbine conditions. Hence, a reaction mechanism with 48 species and 500 elementary reactions is recommended for future studies.