Demonstration of a Process Intensification Scenario for Producing Ammonia Synthesis Gas without an Air Separation Unit Using Soec Technology

Like conventional technologies, green ammonia production usually produces nitrogen through a cryogenic Air Separation Unit (ASU). An ASU requires up to 10% of CAPEX and 1% of electricity in a green ammonia plant. With recent development in Solid Oxide Electrolyzer Cells (SOEC) technologies, by proper process intensification, ASU could be eliminated from the green ammonia plant. A SOEC unit produces hydrogen from steam at high temperatures (700-800 °C), opening up heat integration potential with the exothermic Haber Bosch reaction. As a bonus, the process utilize the unique capabilities of SOEC to act as an oxygen separation membrane and its ability to utilize heat in lieu of power. The burning of air generates extra steam, which further could be electrolyzed again. Still, due to the high efficiency of SOEC, being close to 100 %, the net result is only a marginal increase in overall power consumption. The process ensures far better scalability of an electrified ammonia plant, as a much lower investment can be realized due to the elimination of the air separation unit. This work details this new synthesis gas production process and presents experimental results demonstrating 1000 hours of operation of this novel production pathway using a 25 kW synthesis gas production unit (10 Nm3/h ammonia synthesis gas).