Demonstration of On-demand Ammonia Production by High Pressure Microwave-Assisted Gas Catalysis

A. Welsh, R. Weiss, S. Melkote, J. Hu, C. Wildfire
Malachite Technologies, Inc,
United States

Keywords: microwave-assisted processing, ammonia generation, gas catalysis


The development and distribution of carbon-free, renewable fuel sources is urgently needed to meet the energy demands of a warming planet in the 21st century. Ammonia (NH3) is recognized as a versatile chemical that can be used directly as an energy dense fuel or as a carrier for hydrogen offering safe economical transport through established infrastructure. Hydrogen, of course, can be used as a combustion fuel or as a feedstock for fuel cells that, in turn, provide electricity. Today, the production of ammonia uses hydrogen with the hydrogen being obtained by steam methane reforming performed at massive centralized production facilities requiring 24/7 operation. The result of the combined processes for ammonia production is a high carbon emissions industry requiring 1-2% of the world’s energy production to support a centralized production capacity that is not compatible with decentralization, nor with the use of intermittent renewable energy sources. Our work aims to demonstrate the ability to ‘scale-down’ the ammonia production process so that it can operate economically while being located near the end user, powered by renewable energy sources and capable of on-demand generation. Through our collaboration with the National Energy Technology Laboratory (NETL), West Virginia University (WVU) and the ARPA-E REFUEL program, Malachite Technologies has developed a suite of microwave-assisted gas catalysis reactors capable of flowing reactants at high pressure (up to 1000psi) over catalyst coated monoliths. Utilizing microwave heating at 2.45GHz and 915MHz enables instant, volumetric heating of the coated monoliths for efficient energy transfer and designs have been adapted for both mono- and multi-mode configurations supporting fundamental research and industrial scale implementation of the technique. In parallel, our partners at WVU and NETL have developed a Ru/Cs based catalyst that is shown to reduce the processing temperature and increase ammonia productivity compared to traditional joule heating. We present here an overview of the reactor designs, the development of the catalyst material system, and examples of integrated ammonia production platforms.