The advancement on carbon-free ammonia fuels for gas turbine: A review

This review assesses the feasibility of carbon-free ammonia fuels as an alternative fuel for gas turbines to alleviate the environmental problems associated with excessive carbon emissions. Its advantages and disadvantages are analyzed in terms of fuel properties and practical applications, and measures are presented, focusing on those deficiencies. Given the enormous prospects demonstrated by recent progress in exploring ammonia-fueled gas turbines, here, we review these key developments, starting from the performance and emissions, to operational stability, to emerging technologies, and then to the technical challenges that must be addressed. Moreover, the significance of ammonia-hydrogen blend fuel is highlighted to probe a technological path toward carbon-free fuels for gas turbines: What should be spotlighted is the blending ratio, in which there are dilemmas, including flashback and overheating, with high ratios due to the immaturity of existing technologies, while a reasonable wall cooling effect is concerned with lower ratios. Ammonia-driven integrated chemically recuperated gas turbines are a promising option for such dual-fuel systems at present. These developments broadly bridge ammonia fuels and gas turbines and provide a fresh impetus for the future transition to a low-carbon society.