Modelling of green ammonia production based on solid oxide cells as electrolyser and oxygen separator for Haber-Bosch loop decarbonization

Ammonia is a well-known chemical and a rising candidate as hydrogen carrier. Nevertheless, its synthesis process decarbonization is a preliminary target. Since the Haber-Bosch loop is still the best path guaranteeing a high yield and capacity, alternative hydrogen and nitrogen upstream production steps have to be identified. Based on the water electrolysis, Power-to-Ammonia application allows for coupling the high performing traditional production process with renewables. This configuration would minimise the environmental impacts and make a decentralised local production feasible; nevertheless, its competitiveness strictly depends on reducing the electricity demand. Looking for low consumption electrolysis technologies, the work presents high-temperature solid oxide cells as one of the most competitive solutions showing a double operation, as hydrogen generator and as oxygen concentrator, which leads to H2–N2 mixture synthesis with a low energy demand (∼8.5 kWh/kg NH3) by optimizing the heat recovery and simplifying the plant design.