Of all the devices that can convert the chemical energy in ammonia to electricity, gas turbines and fuel cells appear to be receiving the lion’s share of development effort, outstripping that devoted to ammonia-fueled internal combustion engines (A-ICEs). An Ammonia Energy review last year found a number of organizations with histories of work on A-ICE technology, but reports of progress have not been forthcoming.
It was good news, therefore, when a representative of a newly engaged group appeared at the NH3 Energy+ Topical Conference earlier this month and delivered a talk on an innovative A-ICE “combustion strategy.” Donggeun Lee from the Department of Mechanical Engineering at Seoul National University (SNU) delivered the paper, entitled “Development of new combustion strategy for internal combustion engine fueled by pure ammonia,” on behalf of his co-authors, Hyungeun Min, Hyunho Park, and Han Ho Song.
In the race to place the automotive sector on a sustainable footing, the field is dominated by just two horses: battery-electricity and hydrogen fuel cells. The economic implementation of BEVs is already well underway, with motor companies on track in 2017 to sell more than a million vehicles globally for the first time. The economic implementation of FCVs is also in progress, albeit at a much earlier stage, and has the backing of major motor companies and public-sector agencies. Given the huge leads enjoyed by electricity and hydrogen, ammonia is scarcely seen as a contending fuel. Earlier this month, though, the U.S. Department of Energy’s ARPA-E unit published an interview with two of its program managers that has an intriguing implication: the race is far from over and ammonia may yet break to the front of the pack.
The University of Western Australia has entered the increasingly competitive field of ammonia energy research in Australia, announcing a collaborative agreement to develop "the world's first practical ammonia-powered vehicle" as well as an "ammonia-based hydrogen production plant."
These goals are supported by funding from the R&D arm of Shenhua Group, formerly a coal company but now "China's largest hydrogen producer with a production capacity to power 40 million fuel cell passenger cars."
In the last 12 months ...
The maritime industry has begun assessing ammonia as a carbon-free fuel, for internal combustion engines and fuel cells. This marks the first time since the 1960s, when NASA used ammonia to fuel the X-15 rocket plane, that industry players have seriously considered ammonia for transport applications.
A paper has just been published by researchers in The Philippines who set out to determine the most environmentally benign way to produce, transport, and use ammonia as a fuel for vehicles.
This new work provides a detailed life cycle analysis of a broad range of ammonia technologies, evaluating both carbon and nitrogen footprints of each, and identifying the optimal "well-to-wheel" pathway. Their results support the idea that using ammonia for energy presents a safe and sustainable way to bring about the hydrogen economy.
On April 27 the on-line journal Science Advances published “Carbon-free H2 production from ammonia triggered at room temperature with an acidic RuO2/γ-Al2O3 catalyst.” The lead author, Katsutoshi Nagaoka, and his six co-authors are associated with the Department of Applied Chemistry at Oita University in Japan. The innovation featured in the paper could prove to be an important enabler of ammonia fuel in automotive applications.
Next month the print edition of Fuel Processing Technology will feature a paper entitled “Auto-ignition of a carbon-free aqueous ammonia/ammonium nitrate monofuel: a thermal and barometric analysis.” This title is provocative. First, what is this idea of a fuel composed of a mixture of ammonia and ammonium nitrate (AN)? If ammonia is a good fuel, is it made better with the addition of ammonium nitrate? Second, why is it aqueous? Is the presence of water a feature or a bug? Third, what is a monofuel and why is this term used when the fuel is a mixture of two molecular species? And finally, why is the paper ultimately about auto-ignition?
The shipping industry is beginning to evaluate ammonia as a potential "bunker fuel," a carbon-free alternative to the heavy fuel oil (HFO) used in maritime transport.
International trade associations are leading the effort to decarbonize the sector, in alignment with targets set by the Paris Climate Agreement. Their immediate challenge is simple to state but hard to solve: "ambitious CO2 reduction objectives will only be achievable with alternative marine fuels which do not yet exist." In the long-term, however researchers recognize that "fuel cell-powered ships are likely to dominate, drawing their energy from fuels such as hydrogen and ammonia."
The American Institute of Chemical Engineers (AIChE) will present a Webinar on December 21 on "Distributed Ammonia Synthesis." The presenter will be Edward L. Cussler, Distinguished Institute Professor at the Chemical Engineering and Materials Science Department of the University of Minnesota.
Distributed ammonia synthesis is one focus related to ammonia energy at the University of Minnesota - but just one. In fact, UMinn is the locus of a unique and globally significant collection of research efforts that promise to have significant impacts in the ammonia industry and the broader energy sector.
Ammonia energy proponents look forward to the day when their fuel is used in internal combustion engines – but the state of this art is unsettled and it is not clear which combustion technologies will win in the end.