Nuclear Production of Hydrogen, Fourth Information Exchange ...

SOUTH AFRICA’S NUCLEAR HYDROGEN PRODUCTION DEVELOPMENT PROGRAMME
decomposition reactor. The “attraction” of employing sulphuric acid in the thermoelectrochemical
splitting of water lies in the fact that the applied voltage is greatly reduced compared to normal water
electrolysis. This technology does however come at a “price”, or its own set of challenges, which is
directly linked to the employment of sulphuric acid in high concentrations. At the core of these
challenges are: i) materials; ii) the electro-catalyst; iii) the proton exchange membrane. A number of
key collaboration agreements as well as associations have been entered into so as to pool resources in
tackling these challenges.
With regard to the electro-catalyst the main research issue is to identify a platinum-based catalyst,
i.e. a binary, ternary or quaternary catalyst composed of platinum and one or more transition metals
that will be more active (and thereby further reducing the applied potential), exhibit an improved
lifespan, and have reduced platinum loadings to reduce the cost. The NWU, located in the North-West
province of South Africa where the majority of the world’s platinum is mined and produced, is currently
setting itself up for the synthesis, characterisation and testing of platinum-based electro-catalysts
specifically for normal water electrolysis as well as for SO 2 electrolysis.
The proton exchange membrane has to be improved so as to reduce resistance across the
membrane and the transfer of sulphur species across the membrane that results in the deposition of
sulphur on the cathode thereby poisoning the cathode. The focus will initially be on testing membranes
developed for fuel cells. The NWU will be acquiring and testing fuel cell membranes which include
the three top membranes in meeting the minimum requirements as set by US DOE for 2008, from
Professor P. Pintauro (Vanderbilt University, Nashville, USA), Dr. R. Wycisk (Case Western Reserve
University, Cleveland, USA) and Giner Electrochemical Systems Inc.
In targeting these challenges collaborative agreements have been entered into between the
North-West University (RSA), Giner Electrochemical Systems Inc. (USA), as well as Savannah River
National Laboratory (USA).
Hybrid sulphur pilot plant
In order to demonstrate the integrated operation of a HyS system a HySPP will be designed, constructed
and operated to verify the HyS concept and the scalability of the process as well as investigating
various expected integration challenges. This project will entail a concept design of a HySPP that will
demonstrate the critical R&D requirements needed for commercial application as well as the
development of a HySPP cost estimate and schedule in an iterative manner until the design, cost and
schedule has matured. A detail engineering design of the HySPP will be performed. The HySPP will be
constructed and pre-commissioned after which the final commissioning of the HySPP will be performed.
The HySPP will be used to demonstrate the physical integrity of the HyS process, develop start-up and
shutdown procedures, confirm reaction characteristics and reactor design parameters for commercial
facility design and cost information and will assist in resolving issues related to integration with a
HTGR reactor for commercial demonstration.
The development of the HySPP is a crucial step in the scale-up of the HyS technology. This
will build on the HyS component development and R&D project. The HySPP is also an important risk
mitigation tool as supplier (and supply chain) evaluation, system integration, human capital
development, scale-up verification, proof of concept, materials of construction verification and
various other risks will be mitigated before proceeding with basic and detail design of the commercial
HyS plant.
Plasma-arc reforming
Plasma reformation of natural gas is a relatively new process compared to steam methane reforming
(SMR). The technical application of the plasma-arc goes as far back as the beginning of the 20 th century
where it was used for the production of nitrogen oxides from air, which forms the basis for the
production of fertilisers. This technology was also used in the production of acetylene from light
hydrocarbons (Blom, 2008). The plasma-arc process has the following advantages:
• Using nuclear-based electricity to power the plasma-arc reforming process saves fossil fuels.
• It reaches high temperatures and high power densities. This has the advantage that high
reaction rates can be achieved and smaller reaction equipment is required.
210 NUCLEAR PRODUCTION OF HYDROGEN – © OECD/NEA 2010