Tag Archives: Catalysts

Ammonia Synthesis Via Radiofrequency Plasma Catalysis

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

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

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

Importance of Reaction Mechanism Involved in Design of the Catalyst and the Reactor for Future Ammonia Synthesis

Ken-ichi Aika, Tokyo Institute of Technology, Japan

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

ABSTRACT

The ammonia synthesis reaction is considered to involve several elementary steps [1]:

N2 + 2* → 2N(a) (1)
H2 + 2* → 2H(a) (2)
N(a) + H(a) → NH(a) + * (3)
NH(a) + H(a) → NH2 (a) + * (4)
NH2 (a) + H(a) → NH3(a) + * (5)
NH3(a) → NH3 + * (6)

Here, the symbol * indicates empty sites. For most metal catalysts, the dissociative adsorption of dinitrogen (step 1) is the rate-determining step, and all the other steps and its reverse step (from 2 to 6) are fast enough to be almost in equilibrium for each reaction step. The synthesis rate is considered to be the same as the rate for step (1), and is proportional to the dinitrogen pressure and square of the empty site concentration. Continue reading

Nitride-Based Step Catalysis for Ammonia Synthesis at Atmospheric Pressure

Peter Pfromm, Michael Heidlage*, Bin Liu, Nannan Shan, Viktor Chikan, Hongfu Luo, Nate Flesher
Kansas State University, United States

NH3 Fuel Conference, Minneapolis, November 2, 2017
AIChE Annual Meeting, Topical Conference: NH3 Energy+

ABSTRACT

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 also be included. Continue reading

Exploring Peptide-Bound Catalysts for Electrochemical Ammonia Generation

Charles Loney1*, Ashley Graybill1, Cheyan Xu1, Julie Renner1, Prashant Acharya2, David Suttmiller2, Lauren Greenlee2, Luke Wiles3, Katherine Ayers3, Wayne Gellett3
[1] Case Western Reserve University; [2] University of Arkansas; and [3] Proton OnSite, United States

NH3 Fuel Conference, Minneapolis, November 2, 2017
AIChE Annual Meeting, Topical Conference: NH3 Energy+

ABSTRACT

Today, most ammonia (NH3) manufacturing occurs via the Haber-Bosch process. This process consumes hydrogen from fossil fuels, and as a result NH3 contributes the highest amount of greenhouse gas emissions out of the top 18 large-volume chemicals made globally. Because the process is high temperature (400°–500°C) and pressure (150–300 atm) with a low (15%) single-pass conversion efficiency, the plants have to be very large to be economical. This means that ammonia is shipped from centralized locations, further increasing greenhouse gas emissions because of the fuel consumed in transportation. Additionally, their large size makes it difficult to integrate with renewable sources of hydrogen, such as electrolysis. Continue reading

LiH Mediated Ammonia Synthesis Under Mild Condition

Jianping Guo, Ping Chen*
Dalian Institute of Chemical Physics, China

NH3 Fuel Conference, Minneapolis, November 2, 2017
AIChE Annual Meeting, Topical Conference: NH3 Energy+

ABSTRACT

Having a hydrogen content of 17.6 wt% NH3 is an attractive hydrogen carrier. The key issue for NH3 synthesis and decomposition is the development of non-noble metal based, highly active and stable catalysts that can be operated under mild condition. With the understanding on the interaction of LiH and Li2NH with 3d metals or their nitrides, novel catalyst systems, i. e., LiH-3d transition metals for NH3 synthesis and Li2NH-3d transition metal for NH3 decomposition, that have activities surpassing the highly active Ru-based catalysts were developed. The unique chemistry among TM, Li, N and H creates a two-reactive center mediated pathway favouring NH3 synthesis / decomposition over both early and late 3d transition metals under mild condition, i.e., detectable NH3 formation rates can be obtained at 150 °C over the Mn-, Fe- and Co-LiH composite catalysts, respectively. The characterization of intermediate phases and surface clusters of the catalysts allow the elucidation of the step-wise reaction pathway and the interpretation of catalytic mechanism. Continue reading

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

Hideyuki Matsumoto*, Javaid Rahat, Tetsuya Nanba
National Institute of Advanced Industrial Science and Technology (AIST), Japan

NH3 Fuel Conference, Minneapolis, November 2, 2017
AIChE Annual Meeting, Topical Conference: NH3 Energy+

ABSTRACT

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) agree that process technologies on energy conversion of renewable electricity into hydrogen energy carrier are very useful 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. Continue reading

Early Transition Metal Carbide and Nitride Supported Catalysts for Ammonia Synthesis

Zixuan Wang*, Levi T. Thompson
University of Michigan, United States

NH3 Fuel Conference, Minneapolis, November 2, 2017
AIChE Annual Meeting, Topical Conference: NH3 Energy+

ABSTRACT

More than 180 million tons of NH3 are produced annual via the Haber-Bosch process which converts N2 and H2 at high temperatures (400 – 500°C) and pressures (150 – 300 bars). Ammonia synthesis also accounts for 1-2% of global energy consumption.1 The development of higher activity catalysts that can operate under less severe conditions would enhance the economics associated with and sustainability of NH3 synthesis.

Research described in this paper investigates the performance of transition metal carbide and nitride supported metals for NH3 synthesis. Previously, Mo2C and Mo2N have been reported to be more active than Ru-based catalysts, but slightly less active than the doubly-promoted Fe catalyst typically used in industrial processes.2 To enhance the performance of the bulk carbides and nitrides, we introduced metals including Fe and Ru. While carbide and nitride supported metal catalysts have typically been produced using the passivated supports, the method that we used allows for direct interaction between the metal and support material. Continue reading

Nitrogenase Inspired Peptide-Functionalized Catalyst for Efficient, Emission-Free Ammonia Production

Stephen Szymanski*, Wayne Gellett
Proton OnSite, United States

NH3 Fuel Conference, Minneapolis, November 1, 2017
AIChE Annual Meeting, Topical Conference: NH3 Energy+

ABSTRACT

Ammonia-based fertilizers have enabled increases in food production to sustain the world’s population. Currently the major source of ammonia is the Haber-Bosch process, which requires high temperature and pressure and has low conversion efficiency, such that very large plants are required for economical production. Ammonia is therefore one of the most energy and carbon intensive chemical processes worldwide, largely due to the steam methane reforming step to produce the required hydrogen. Because of the very large plant scale and resulting centralization of production, ammonia may also be transported long distances to point of use, adding additional energy and emissions. Distributed, sustainable ammonia production would therefore have a huge impact on global energy use and related carbon emissions. Electrochemical solutions are well-suited to modularity and integration with renewable energy sources and can operate at much milder temperatures and pressures, but a catalyst is needed which is selective to ammonia generation vs competing reactions. Continue reading

Nitrogen-Based Fuels: Renewable Hydrogen Carriers

Gideon S. Grader*, Michael Epstein, Ayillath Kutteri Deepa, Oren Elishav, Gennady E. Shter, Bar Mosevitzky
Technion – Israel Institute of Technology, Israel

NH3 Fuel Conference 2017, Minneapolis, November 1, 2017
AIChE Annual Meeting, Topical Conference: NH3 Energy+

ABSTRACT

Renewable energy sources such as solar and wind suffer from an intermittent power output, making energy storage a key element in future energy infrastructure. Fuels offer both high energy densities and efficient transport compared to other energy storage alternatives. One energy storage solution is water electrolysis. However, the generated hydrogen is incompatible with the global fuel infrastructure, inhibiting its implementation as an energy vector. Storing hydrogen on carrier atoms provides a safe and convenient way to utilize and transport renewable energies. While carbon–based fuels are commonly suggested, using nitrogen as a hydrogen carrier can potentially offer a superior option. Continue reading