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The Potential for Hydrogen Ironmaking in New Zealand

Abstract

Globally, iron and steel production is responsible for approximately 6.3% of global man-made carbon dioxide emissions because coal is used as both the combustion fuel and chemical reductant. Hydrogen reduction of iron ore offers a potential alternative ‘near-zero-CO2’ route, if renewable electrical power is used for both hydrogen electrolysis and reactor heating. This paper discusses key technoeconomic considerations for establishing a hydrogen direct reduced iron (H2-DRI) plant in New Zealand. The location and availability of firm renewable electricity generation is described, the experimental feasibility of reducing locally-sourced titanomagnetite irons and in hydrogen is shown, and a high-level process flow diagram for a counter-flow electrically heated H2-DRI process is developed. The minimum hydrogen composition of the reactor off-gas is 46%, necessitating the inclusion of a hydrogen recycle loop to maximise chemical utilisation of hydrogen and minimize costs. A total electrical energy requirement of 3.24 MWh per tonne of H2-DRI is obtained for the base-case process considered here. Overall, a maximum input electricity cost of no more than US$80 per MWh at the plant is required to be cost-competitive with existing carbothermic DRI processes. Production cost savings could be achieved through realistic future improvements in electrolyser efficiency (∼ US$5 per tonne of H2-DRI) and heat exchanger (∼US$3 per tonne). We conclude that commercial H2-DRI production in New Zealand is entirely feasible, but will ultimately depend upon the price paid for firm electrical power at the plant.

Funding source: This research was supported by funding received from the New Zealand Endeavour Fund, Grant no.: RTVU1907. Some data reported in this paper was taken on the Wombat beamline at the ANSTO neutron scattering facility, supported by Grant number 5895
Related subjects: Applications & Pathways
Countries: New Zealand
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2022-10-20
2022-11-30
http://instance.metastore.ingenta.com/content/journal3897
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