3rd generation ammonia synthesis: new catalysts & production pathways

We look at four new developments this week:

1. A team from DTU Energy and the Dalian Institute of Chemical Physics have uncovered a new class of alternative catalysts for mild condition ammonia synthesis. The ternary ruthenium complex hydrides Li4RuH6 and Ba2RuH6 avoid the energy-intensive pathway of nitrogen dissociation in a "synergistic" manner.

2. A team from the Korea Institute of Machinery and Materials reported a highly selective (95%) plasma ammonia synthesis method.

3. A team from Delft University of Technology has presented an present an "unconventional electrochemical design" that physically separates hydrogen and dinitrogen activation sites.

4. A team at the Max Planck Institute for Coal Research has demonstrated a new mechanochemical ammonia synthesis system that operates at room temperature and pressures as low as 1 bar.


Ammonia Synthesis from Water and Nitrogen Under Ambient Condition Using Single Atom Nickel

Our dependence on ammonia is not limited to development of fertilizers and other chemicals. Ammonia is being considered an energy vector, capable of being used for energy storage as well as fuel, due to its high energy density, ease of storage and transportation. Growing need for ammonia has forced development of alternate strategies for synthesis worldwide to serve as back up of Haber Bosch. Electrochemical ammonia synthesis is one such alternative. Earlier, we found that, nitrogen vacancy in metal-organic framework-derived disordered carbon is active for nitrogen reduction in alkaline electrolytes. We tried to investigate Fe-N4 sites for nitrogen reduction. It…


Yittria-Stabilized Zirconia (YSZ) Supports for Low Temperature Ammonia Synthesis

NH3 is important as the raw material for fertilizer production and high hydrogen density (17.7 wt. %) energy carrier. Conventionally, NH3 is synthesized through the well-known Haber-Bosch process at 400-500°C and P~150 bar. Both critical reaction conditions and massive production (145 mt NH3 in 2014 globally) make it one of the most energy extensive process, consuming 1-2% of the world’s total energy expense. Here we introduce YSZ as a more active Ru catalyst support than traditionally used supports such as Al2O3. The addition of Cs promoter increased rates an order of magnitude higher by reducing the apparent activation energy from…


Microwave Catalytic Synthesis of Ammonia for Energy Storage and Transformation

This paper presents an innovative approach of producing energy-dense, carbon-neutral liquid ammonia as a means of energy carrier. The approach synergistically integrates microwave reaction chemistry with novel heterogeneous catalysis that decouples N2 activation from high temperature and high pressure reaction, altering reaction pathways and lowering activation energy. Results have shown that ammonia synthesis can be carried out at 280 ℃ and ambient pressure to achieve ~1 mmol NH3/g cat. /hour over supported Ru catalyst systems. Adding promoters of K, Ce and Ba has significantly improved the ammonia production rate over Ru-based catalysts that could be attributing to enhanced electromagnetic sensitivity…


300°C Proton-Exchange Membrane for Low-Pressure Electrolytic Ammonia Synthesis

The two North Dakota universities and Proton OnSite are developing a 300°C-capable polymer–inorganic composite (PIC) proton exchange membrane for low-pressure (15-psi) ammonia synthesis. The PIC membrane comprises an inorganic proton conductor strategically composited within a high-temperature polymer to enable a proton conductivity of 10-2 siemens/centimeter at 300°C. Integrated with appropriate low-cost anode and cathode catalysts in a membrane–electrode assembly, the gas-impermeable PIC membrane is projected to enable ammonia production at a total energy input of about 6400 kilowatt-hours/ton (kWh/ton), versus about 8500 kWh/ton for state-of-the-art Haber Bosch-based ammonia production. The PIC membrane will also have application in high-temperature water electrolysis…


Starfire Energy’s 10 Kg/Day Rapid Ramp NH3 System Development

Starfire Energy is building a 10 kg/day NH3 synthesis system using its low pressure Rapid Ramp NH3 process. The system includes hydrogen production by proton exchange membrane electrolyzer, nitrogen production by pressure swing adsorption, NH3 synthesis, and liquid NH3 storage. The tight coupling of the hydrogen, nitrogen, and NH3 processes require minimal reactant buffering. The system design, status, and preliminary performance will be discussed.


Demonstration of CO2-Free Ammonia Synthesis Using Renewable Energy-Generated Hydrogen

In Japan, the government funding project SIP, Strategic Innovation Promotion Program, supports the research, development and demonstration of “Energy Carriers”. The concept of the “Energy Carriers” value chain is to produce hydrogen energy carriers overseas from fossil resources using CCS or renewable energy, and transport it to Japan for utilization as clean energy. The purpose of the program is to help realize a low-carbon society in Japan by using hydrogen. Among energy carriers, ammonia is the one of the most promising carriers, because of the ease of transportation as a liquid, higher hydrogen density, and proven technologies for commercial and…


A Low Pressure Membrane Based Renewable Ammonia Synthesis

Ammonia is currently mostly produced by the highly energy and carbon-intensive Haber–Bosch process, which requires temperatures of 450–500 °C and pressures of up to 200 bar. The feedstock for this process is hydrogen from natural gas (NG), coal or oil, and nitrogen produced from air by cryogenic route or pressure swing adsorption (PSA). The share of NG, coal and fuel oil feedstock for the global production of ammonia is 72%, 22% and 4% respectively, contributing to approximately 420 million tons of CO2 emissions per annum, representing over 1% of global energy related emissions. The energy consumed for ammonia synthesis by…


Microwave Catalysis for Ammonia Synthesis Under Mild Reaction Conditions

A scalable, cost-effective catalytic process of ammonia synthesis is developed by using microwave excitation under mild reaction conditions. In this research project funded by DOE ARPA-E, our interdisciplinary team of WVU, NETL, PNNL, FSU and two industrial partners have demonstrated that ammonia synthesis can be carried out at 200-300 °C and ambient pressure. This transformational process integrates system elements of electromagnetic sensitive catalysts and microwave reactor design. Taking advantages of state-of-the art non-equilibrium microwave plasma technology, catalytic ammonia synthesis undergoes a new reaction pathway where the barrier for the initial dissociation of the dinitrogen is decoupled from the bonding energy…


Advanced Catalysts Development for Small, Distributed, Clean Haber-Bosch Reactors

The traditional Haber-Bosch (HB) synthesis of anhydrous ammonia will adapt to clean power by sourcing the hydrogen from renewable electrolysis. However, the very large scale of current HB plant designs are not well-matched to smaller and more distributed clean power resources. Plant/reactor designs need to be made at a smaller scale in order to best utilize clean hydrogen. Small, megawatt scale HB reactors have an additional advantage of being better able ramp up and down with variable renewable power. This talk will detail ARPA-e funded work into the design and optimization of these smaller, clean NH3 reactors, which utilize much…