This project is based at the University of Sheffield and is sponsored by Paralloy, and seeks candidates with a 2.1 or 1st class degree in a STEM discipline. If English is not your first language you must have IELTS 7.0 (or equivalent).
The ongoing climate emergency necessitates a radical re-examination of fuel sources and the identification of technologies to aid the transition towards net-zero emissions. Hydrogen is routinely identified as critical to the decarbonisation of several industrial sectors from transportation to advanced manufacturing.
The most readily utilised production method of hydrogen is via steam-methane reforming. In this process, high temperature steam (700-1000˚C) reacts with methane (commonly from natural gas) under high pressures (up to 25 bar) in the presence of a catalyst to produce hydrogen and carbon dioxide, which is subsequently captured and stored underground. Whilst this method of producing “blue hydrogen” is certainly not zero-carbon, it enables the transition towards increased utilisation of hydrogen as a fuel source until green hydrogen production routes can be improved.
In addition, experience with blue hydrogen allows the design of materials that can withstand the inimical conditions encountered during hydrogen production as well as providing improved understanding of the corrosion implications associated with the presence of hydrogen. However, a critical requirement for the continued supply of blue hydrogen, and indeed for an increase in production, is the improvement in the alloys used in the reformer to design against creep and fatigue degradation and corrosive attack including carburisation and coking.
Currently, the alloys of choice available in the open market for reformer applications resemble austenitic steels or Ni-based superalloys strengthened by significant carbide networks. Tubes used in reformer applications are produced through spin casting in large sections and as a result the manufacturing process is integral to the alloy development process. For the past three to four decades the improvement to reformer alloys have been marginal and steady, with the main alloying elements being Ni and Cr. With the introduction of Paralloy H39WM+ which has much improved creep resistance to the previous generation of alloys used for reformer tubes, thinner tubes can be manufactured. This potentially reduces the energy usage per ton of blue hydrogen produced.
The prospect of hydrogen usage increasing in the coming years and more efficient ways of producing blue hydrogen is regarded as viable perception to contribute towards reduced carbon emission. To achieve this an alloy with superior creep resistance than H39WM+ at reformer operating temperature has to be developed, taking into consideration the operating conditions and manufacturing process or limitations.
This overarching project aim is to develop a new reformer alloy with an improved critical lifetime that can be readily manufactured using spin casting without additional post-casting operations. The following objectives will form part of the methodology of the project:
• Characterisation of H39WM+ to understand capabilities, microstructural constitution, manufacturability.
• Create experimental manufacturing protocol to mimic spin casting solidification rates (in house strip caster and additive manufacturing methods to enable matching of spin casting cooling rates).
• Exploration of solid solution strengthening and carbide optimisation methods using computational tools.
• Evaluation of creep performance and determination of creep mechanisms in H39WM+ and developmental alloys.
• Experimental investigation, microstructural characterisation, and property evaluation of downselected alloys.
• Advanced diffraction experiments at central facilities (Diamond, ISIS etc) to probe in situ microstructural evolution and surface stability will also be considered.
This project will run in close collaboration with Paralloy where an extended placement may be considered if deemed beneficial to the overall programme.
The Centre for Doctoral Training in Advanced Metallic Systems is a partnership between industry and the Universities of Sheffield, Manchester and I-Form Advanced Manufacturing Centre, Dublin. CDT students undertake a 4-year doctorate with an in-depth compulsory technical and professional skills training programme. Please review our training programme, application process and full entry requirements at www.metallicscdt.co.uk. Please note, application is only via the University of Sheffield (see website), and general enquiries can be made to the CDT ([Email Address Removed]). For more information on the research scope of the project please contact Kathy Chrisofidou ([Email Address Removed]).
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