Site items in: Low-pressure Ammonia Synthesis

Vanadium As a Potential Catalytic Membrane Reactor Material for NH3 Production
Paper

Vanadium As a Potential Catalytic Membrane Reactor Material for NH3 Production

Simona LiguoriJennifer Wilcox October 31, 2018

In solid or liquid states, ammonia salts and solutions are the active components of most synthetic fertilizers used in agriculture, which consume 83% of the world’s ammonia. Today, ammonia for fertilizers is industrially produced via the Haber-Bosch process at 400-500 °C and at pressures up to 30 MPa (300 bar). These harsh operating conditions are necessary due to the high affinity of dissociated nitrogen atoms towards the catalyst surface in addition to the high barrier associated with N2 dissociation. For these reasons, the need for advanced catalytic methods for the reduction of N2 to ammonia remains a requirement for sustainability…

Ammonia Absorption and Desorption in Ammines
Paper

Ammonia Absorption and Desorption in Ammines

Collin SmithMahdi MalmaliChen-Yu LiuAlon McCormickEdward Cussler October 31, 2018

While adsorption onto solids is a common separation process, absorption into solids is much less often used. The reason is that absorption is usually assumed ineffective because it includes very slow solute diffusion into the solid. An exception may be the separation of ammonia from nitrogen and hydrogen using ammines, especially at temperatures close to those used in ammonia synthesis. There, ammonia can be selectively absorbed by calcium chloride; nitrogen and hydrogen are not absorbed. The kinetics of ammonia release seem to be diffusion controlled. The kinetics of absorption are consistent with a first order reaction and diffusion in series,…

Nitride-Based Step Catalysis for Ammonia Synthesis at Atmospheric Pressure
Paper

Nitride-Based Step Catalysis for Ammonia Synthesis at Atmospheric Pressure

Peter PfrommMichael HeidlageBin LiuNannan ShanViktor ChikanHongfu LuoNate Flesher November 2, 2017

Formation of metal nitrides to activate dinitrogen is one avenue to ammonia and other nitrogen compounds. Attractive aspects are operation at atmospheric pressure and moderate temperatures, formation of stable chemical intermediates rather than reliance on somewhat sensitive heterogeneous catalysis, and inexpensive materials. If a single metal is used, however, one encounters tradeoffs somewhat akin to the well-known tradeoffs for Haber-Bosch catalysts. Results will be presented for metal nitride-based ammonia synthesis, and new metal alloys that can address some of the tradeoffs between affinity for nitrogen, and formation of ammonia when hydrogen is added. Options using water instead of hydrogen will…

Influence of H2 / N2 Ratio on Dynamic Behavior of Ammonia Production on Ru Catalyst Under Low Pressure Condition
Paper

Influence of H2 / N2 Ratio on Dynamic Behavior of Ammonia Production on Ru Catalyst Under Low Pressure Condition

Hideyuki MatsumotoJavaid RahatTetsuya Nanba November 2, 2017

Recently deployment of renewable energy such as sunlight and wind power or deployment of process technologies for carbon dioxide capture and storage (CCS) is indispensable to reduce the CO2-emission. However, there are some issues to be solved in order to accelerate the mass deployment of renewable energy. Since amount of renewable energy quite changes unstably with time, which depends on weather and place, development of process systems technology is an issue for stable and effective utilization of electric power that is generated by fluctuating renewable energy. Those in national institute of National Institute of Advanced Industrial Science and Technology (AIST)…

Atmospheric-Pressure Synthesis of Ammonia Using Non-Thermal Plasma with the Assistance of Ru-Based Multifunctional Catalyst
Paper

Atmospheric-Pressure Synthesis of Ammonia Using Non-Thermal Plasma with the Assistance of Ru-Based Multifunctional Catalyst

Peng PengYanling ChengNan ZhouRaymond HatzenbellerPaul ChenRoger Ruan November 2, 2017

Ammonia has much more uses than being a fertilizer. Its emerging applications include hydrogen carrier, fuel cells, clean transportation fuels, and other off-grid power applications. The traditional Haber Bosch process used to synthesize ammonia must be achieved at high temperature and pressure. The non-thermal plasma (NTP) allows for the synthesis of ammonia at a lower temperature and pressure conditions. It is proposed that the moderate process conditions can potentially allow a more economical construction and operation of ammonia production systems on distributed farms and renewable hydrogen production sites. In this study, we report the NTP synthesis of ammonia using dielectric…

Lower Pressure Ammonia Synthesis
Paper

Lower Pressure Ammonia Synthesis

Mahdi MalmaliAlon McCormickEdward CusslerJoshua PrinceMichael Reese November 1, 2017

Ammonia is a very important chemical, mainly produced through the Haber-Bosch process. This process requires high temperature (>400 °C) and pressure (>150 bar) in order to ensure fast kinetics and high conversions, respectively.1 As a result, ammonia synthesis is known to be very complex and energy-intensive.2 To alleviate the complexity and energy requirements of ammonia synthesis, and to reduce the CO2 emissions, we are proposing an innovative reaction-absorption process to synthesize carbon-free ammonia in small plants.3 This green ammonia can be synthesized in wind-powered plants, with hydrogen from electrolysis of water and nitrogen from pressure swing adsorption of air.4 In…