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

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.