Tag Archives: Ammonia Synthesis

Highly-Selective Electrochemical Reduction of Dinitrogen to Ammonia at Ambient Temperature and Pressure

Posted on December 16, 2018 by | Leave a comment

Qiang Zhang*, Xiaoyang Cui, Cheng Tang, Tsinghua University, China

15th Annual NH3 Fuel Conference, Pittsburgh, PA, October 31, 2018
NH3 Energy+ Topical Conference at the AIChE Annual Meeting

ABSTRACT

Catalytic conversion of dinitrogen (N2) into ammonia under ambient conditions represents one of the Holy Grails in catalysis and surface science. As a potential alternative to the Haber-Bosch process, electrochemical reduction of N2 to NH3 is attractive owing to its renewability and flexibility, as well as sustainability for producing and storing value-added chemicals from the abundant feedstock of water and nitrogen on earth. However, owing to the kinetically complex and energetically challenging N2 reduction reaction (NRR) process, NRR electrocatalysts with high catalytic activity and high selectivity are rare. In this contribution, as a proof-of-concept, we demonstrate that both the NH3 yield and NH3 faradaic efficiency (FE) at ambient conditons can be improved by modification of the hematite nanostructure surface. Continue reading →

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Identifying the Prospects of Electrochemical Ammonia Synthesis on Mxenes Using First Principles Calculations

Posted on December 16, 2018 by | Leave a comment

Gurjyot Sethi, Venkat Viswanathan*, Carnegie Mellon University, USA

15th Annual NH3 Fuel Conference, Pittsburgh, PA, October 31, 2018
NH3 Energy+ Topical Conference at the AIChE Annual Meeting

ABSTRACT

Electrochemical synthesis of ammonia is a major challenge aimed at making production of ammonia sustainable. Currently ruthenium is the transition metal of choice for catalyzing the industrial Haber-Bosch process. However, electrochemical ammonia synthesis on ruthenium suffers from high overpotential and the competing hydrogen evolution reaction. Recently layered transition metals carbides and nitrides (MXenes) have been identified as a potential material class for ammonia synthesis. MXenes are particularly interesting owing to the high degree of tunability in surface chemistry due to the transition metal choice, interlayer distance, number of layers in the material, and surface termination. These choices affect the electron density of the surface and hence the binding strength of MXenes with key intermediates. In this work, we use density functional theory (DFT) to compute adsorption free energies of relevant intermediates to identify MXenes that are promising for ammonia synthesis. Using uncertainty quantification capabilities within the Bayesian error estimation functional (BEEF), we also compute the probability density functions for catalytic activity predictions. We obtain free energy diagrams and scaling relations and finally report prediction confidence values on the limiting potential and insights into the prospects of using MXenes for nitrogen fixation. Continue reading →

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Analysis of influence of operating pressure on dynamic behavior of ammonia production over ruthenium catalyst under high pressure condition

Posted on December 14, 2018 by | 1 comment

Hideyuki Matsumoto*, Javaid Rahat, Yuichi Manaka, Mika Ishii, Tetsuya Nanba, Renewable Energy Research Center, National Institute of Advanced Industrial Science and Technology (AIST), Japan

15th Annual NH3 Fuel Conference, Pittsburgh, PA, October 31, 2018
NH3 Energy+ Topical Conference at the AIChE Annual Meeting

ABSTRACT

Process technologies on energy conversion of renewable electricity into hydrogen energy carrier are significant to deploy long-term storage and long-distance transport of much more renewable inside and outside Japan. Ammonia is a potential hydrogen carrier that contains 17.6 wt% of hydrogen. Moreover, as an energy carrier, ammonia is thought to be a clean fuel as only water and nitrogen are produced on direct combustion.

Many researchers and engineers consider that ammonia plants using hydrogen produced by solar electricity or wind electricity will be much smaller than those currently used [1]. There is an issue of low pressure condition for feed of raw material gas, since hydrogen and nitrogen are produced by water electrolysis and pressure swing adsorption (or cryogenic air separation) respectively. Ammonia synthesis under the conventional pressure conditions needs increase in power for compression of the feed gas. Moreover, low temperature operation has advantage in getting higher ammonia concentration of equilibrium limitation. In order to promote the reaction under the lower pressure conditions, lower reaction temperature condition is desirable due to a limitation of equilibrium.

In Japan, the Japan Science and Technology Agency (JST) supports the research and development of catalyst with high catalytic activities in the low-temperature region, and our research group investigates performance of developed ruthenium catalysts by small-scale ammonia plant that is built in Fukushima Renewable Energy Institute, AIST (FREA). Continue reading →

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A Low Pressure Membrane Based Renewable Ammonia Synthesis

Posted on December 14, 2018 by | Leave a comment

Sarbjit Giddey, CSIRO, Australia

15th Annual NH3 Fuel Conference, Pittsburgh, PA, October 31, 2018
NH3 Energy+ Topical Conference at the AIChE Annual Meeting

ABSTRACT

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 Haber-Bosch process is in the 10 to 15 MWh/tonne range, depending on the type of fossil fuel feedstock used.

In an alternative route renewable hydrogen produced by an electrolyser can be fed to the Haber-Bosch reactor along with nitrogen for ammonia synthesis, and this route has been suggested to consume energy around 12 MWh/tonne of ammonia.

CSIRO has developed a metal membrane based ammonia synthesis process that uses hydrogen and nitrogen as feedstock. The materials and catalyst developed for the process allow the synthesis process at much lower pressures (~ 10 bar) at 450 °C. The synthesis rates achieved are two orders of magnitude higher than with any electrochemical route. The catalyst and the metal / catalyst interfacial structure have been specifically tailored for low pressure ammonia synthesis. The low pressure membrane reactor allows direct coupling to an electrolyser and air separation unit (ASU) operated by a renewable source, thus promising over 25% reduction in the energy input, substantial capital savings on reactors compared to conventional Haber-Bosch process, and allows distributed or centralised ammonia production. Continue reading →

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Microwave Catalysis for Ammonia Synthesis Under Mild Reaction Conditions

Posted on December 13, 2018 by | Leave a comment

Jianli Hu*, Hanjing Tian, Yan Luo, Xinwei Bai, West Virginia University, USA; Dushyant Shekhawat, Christina Wildfire, Victor Abdelsayed, Michael J. Spencer, National Energy Technology Laboratory, USA; Robert A. Dagle, Stephen Davidson, Pacific Northwest National Laboratory, USA; Albert E. Stiegman, Florida State University, USA

15th Annual NH3 Fuel Conference, Pittsburgh, PA, October 31, 2018
NH3 Energy+ Topical Conference at the AIChE Annual Meeting

ABSTRACT

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 of the intermediates. Continue reading →

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Creating a Redox Materials Database for Solar-Thermochemical Air Separation and Fuels Production

Posted on December 13, 2018 by | Leave a comment

Josua Vieten*, Dorottya Guban, Martin Roeb, Christian Sattler, Institute of Solar Research, DLR (German Aerospace Center), Germany; Patrick Huck, Matthew Horton, Kristin Persson, Lawrence Berkeley National Laboratory, USA; Brendan Bulfin, ETH Zurich, Switzerland

15th Annual NH3 Fuel Conference, Pittsburgh, PA, October 31, 2018
NH3 Energy+ Topical Conference at the AIChE Annual Meeting

ABSTRACT

Converting heat from renewable sources into other forms of energy is considered an essential factor in the reduction of greenhouse gas emissions. For instance, high temperatures can be reached using concentrated solar power (CSP), and the thus-captured energy can be converted into so-called solar fuels via thermochemical processes. These consist of the partial reduction of a redox material, usually a metal oxide, at high temperatures following the exothermic re-oxidation of this material at a lower temperature level using steam or CO2, which are thus converted into hydrogen or carbon monoxide, respectively. These two gases can be combined to generate syngas for the production of hydrocarbons (see Fig. 1). Through the same process, a stream of mostly inert gas can be produced by re-oxidation with air, allowing air separation using renewable energy sources. Hydrogen production and air separation can also provide the feedstock for ammonia production through the Haber-Bosch process, as the achieved oxygen partial pressures can be kept low enough to avoid catalyst poisoning. [2] Ammonia produced through this method can be used for fertilizer production, or as a fuel for energy storage. Continue reading →

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Terrestrial Energy, National Lab, Southern Company – Partnership Overview Using Integral Molten Salt Reactor Technology with HyS Acid for Hydrogen Production

Posted on December 13, 2018 by | Leave a comment

John Kutsch, Terrestrial USA, USA

15th Annual NH3 Fuel Conference, Pittsburgh, PA, October 31, 2018
NH3 Energy+ Topical Conference at the AIChE Annual Meeting

ABSTRACT

Demands for safe secure supplies of potable water across the planet are increasing faster than can be provided by natural, ever depleting sources of fresh water. At the same time, world demand for electric power is also accelerating. Making H2 from Natural Gas is not an optimal or efficient process that is also un-economic at higher gas costs. An Integral Molten Salt Reactor (IMSR) is uniquely suited to provide the very high temperatures (585 °C+ working temps.) that are needed to both generate significant amounts of Hydrogen, Oxygen (a feed for industrial oxygen uses) and Electricity needed for advanced economies and industry.

Terrestrial Energy USA, Savanna River National Lab, Sandia National Lab, Idaho National Laboratory, and Southern Company are working to show that this new generation of IMSR would be the only effective system to create an H2 supply utilizing the HyS system to produce Hydrogen. The Hybrid Sulfur (HyS) Hydrogen Generation process has the potential to produce hydrogen gas using both thermal and electrical energy at a cost of <$2/kg. Continue reading →

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Ammonia Synthesis Via Radiofrequency Plasma Catalysis

Posted on December 13, 2018 by | Leave a comment

Javishk Shah*, Maria Carreon, University of Tulsa, USA; Weizong Wang, Annemie Bogaerts, University of Antwerp, Belgium

15th Annual NH3 Fuel Conference, Pittsburgh, PA, October 31, 2018
NH3 Energy+ Topical Conference at the AIChE Annual Meeting

ABSTRACT

Introduction:
In 1909, a compound named Ammonia was discovered. Through the 20th century, the immense potential of this chemical was exploited by using in almost every product, from process industry for fertilizer and chemical production to every use in cosmetics, household cleaners and medicines. Recently, fuel cells operating on liquid ammonia as working fluid have been developed on research scale. Despite of using 1-2% of total energy production for the synthesis of this compound, no significant changes have been made to the process since the first Haber-Bosch process plant has been setup.

Plasma catalysis is the use of plasma and catalyst synergism for the synthesis of various compounds. In case of ammonia synthesis, it helps in shifting the rate-limiting step from nitrogen dissociation to NHx formation. The excitation source helps the molecules to reach excited and ionized states which ensures the abundance of radicals for radicals. Radio-Frequency plasma is once such tool for plasma-catalysis. The synthesis has been explored by Matasumoto et al.[1] but no concrete details about the reaction pathway and plasma-catalyst synergism have been reported. Continue reading →

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

Posted on December 13, 2018 by | 1 comment

Adam Welch*, Jonathan Kintner, Joseph Beach, Starfire Energy, USA; Jason Ganley, Christopher Cadigan, Ryan O’Hayre, Colorado School of Mines, USA

15th Annual NH3 Fuel Conference, Pittsburgh, PA, October 31, 2018
NH3 Energy+ Topical Conference at the AIChE Annual Meeting

ABSTRACT

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 higher and variable space velocities, lower pressures, and gas adsorption rather than condensation for NH3 extraction.

The different synthesis conditions at smaller scale also require a rethinking of the existing HB iron catalysts, which have been optimized for large, low space velocity reactors. New, advanced heterogeneous catalysts, capable of 5X faster nitrogen fixation, will be discussed. This talk will detail the development of the catalyst, including the ternary oxide support and metal nanoclusters, both of which play a key role in the catalyst performance. Many phases of the ternary system were synthesized, characterized for surface area and metal dispersion, and tested in a differential reactor to map catalytic performance to support composition and structure. Additionally, different active metals were attached to the best performing oxide support, to study the activity dependence on metal species.

Read the abstract at the AIChE website.

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RELATED NH3 FUEL CONFERENCE PAPERS

2018: Rapid Ramp NH3 Prototype Reactor Update
2017: Fast-Ramping Reactor for CO2-Free NH3 Synthesis

LINKS

Starfire Energy
Ammonia Synthesis for Fuel, Energy Storage, and Agriculture Applications, ARPA-E OPEN program, 2015
Learn more about the 2018 NH3 Fuel Conference

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Vanadium As a Potential Catalytic Membrane Reactor Material for NH3 Production

Posted on December 11, 2018 by | Leave a comment

Simona Liguori*, Jennifer Wilcox, Worcester Polytechnic Institute, USA

15th Annual NH3 Fuel Conference, Pittsburgh, PA, October 31, 2018
NH3 Energy+ Topical Conference at the AIChE Annual Meeting

ABSTRACT

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 in the food and energy cycle.

The aim of this work is to explore the potential of metallic membranes for N2 separation with the final intent to produce NH3. Based on a preliminary theoretical investigation using density functional theory, the Group V transition metals (e.g., vanadium (V), niobium (Nb) and tantalum (Ta)) show strong affinity toward N2. Continue reading →

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