Techno-economic assessment of a novel oxy-fuel cycle based on steam-nitrogen expansion after ammonia oxidation in a membrane reactor

• An oxy-fuel cycle based on ammonia oxidation in oxygen membrane reactor is studied. • Significant efficiency advantage over steam cycles is found in cogeneration configuration. • A total efficiency equal to 108.4 % is achieved when co-generating power and heat. • Replacing a boiler with a membrane reactor shows good techno-economic profitability. Green ammonia is currently seen as a promising solution for the decarbonisation of several sectors, including the energy industry. In this work, an innovative oxy-fuel cycle concept using ammonia as fuel is proposed, named HiPowAR, where ammonia oxy-combustion is accomplished in an oxygen membrane reactor, avoiding the need for an air separation unit and leveraging the synergy between oxygen permeation and fuel oxidation. Several system configurations are investigated by means of thermodynamic simulations, concluding that the cogeneration application is particularly promising due to the large overall first-principle efficiency achieved, up to 108.4 % (based on lower heating value). The feasibility of replacing a conventional boiler with a HiPowAR membrane reactor in cogeneration applications is evaluated through a techno-economic analysis. Internal rates of return larger than 20 % are observed, considering a 10-year investment horizon, proving the profitability of the investment. The sensitivity analysis shows that an average oxygen flux equal to 1 mL cm −2 min −1 on the membrane can be considered the threshold to make the investment profitable.