Combustion and emission characteristics of ammonia/hydrogen dual-fuelled generic gas turbine

To develop a generic gas turbine dual-fuelled by ammonia/hydrogen with high combustion efficiency and low NO_x emission, an in-depth understanding of combustion and emission characteristics of premixed ammonia/hydrogen flame in generic gas turbine is essential. Over a wide range of equivalence ratios, hydrogen blending ratios and oxygen contents in the oxidizer, an appropriate initial component ratio is firstly selected for subsequent parametric study. The influence of pressure, inlet temperature and secondary air injection on peak heat production rate, outlet temperature and emission (NH₃, H₂, NO_x) are investigated. Results show that the outlet temperature is slightly increased with either pressure augmentation or inlet temperature enhancement. The increase in pressure promotes the reduction of NO_x in the post-flame zone, and it has a greater influence on fuel-bound NO than thermal-NO. An increase of NO emission is found as inlet temperature rises due to the extended Zel’dovich mechanism. In addition, the secondary air injection is beneficial to the improvement of combustion efficiency, but since the NO consumption reaction is incomplete and the nitric oxide is oxidized by excess air, a considerable increase in NO and NO₂ emissions is observed. Thus, it is required to choose an appropriate amount of secondary air to balance the high combustion efficiency and low NO_x emission.