(Invited) Ammonia Production Beyond Haber-Bosch Process

Abstract

Ammonia has been an important chemical precursor for agriculture and other applications for about a century. It is estimated that about 180 million tons of ammonia is produced annually, and over 90% of the ammonia is produced via the Haber-Bosch (HB) process. While the reaction for the Haber-Bosch process is simple (N2+3H2=2NH3), the actual production process is complicate. The first major step is the methane steam reforming process which provides the H2 source. This step consumes significant amount of energy and releases large amount of CO2. For the ammonia synthesis step, it typically requires high pressure such as up to 300 bar at around 400 to 500 oC. Therefore overall the HB process is very energy intensive. It is poorly suited to distributed/small-scale applications, and not suitable for fast ramping/turndown and thus not dispatchable. Thanks to the fast progress on capturing renewable energy such as solar, wind, tidal in recent years, small to medium scale clean energy becomes readily available. Meanwhile the regulations on the CO2 emission has become more and more rigorous and urgent, there seems higher demand to look for alternative and cleaner process on ammonia synthesis. This abstract will cover two parts: a brief review on current progress of ammonia production via non-Haber-Bosch process particularly using ionic conducting ceramic cells and current development and progress at the Colorado School of Mines using the state-of-the-art reversible protonic ceramic fuel cells on ammonia production and power generation.