Dr Karen Steel

Associate Professor

School of Chemical Engineering
Faculty of Engineering, Architecture and Information Technology
karen.steel@uq.edu.au
+61 7 336 53977

Overview

Biography:

1992 - 1995. B.E. (Hons), Bachelor of Engineering (Chemical). The University of Melbourne.

1996 - 1999. Ph.D. (Engineering), Department of Chemical Engineering, The University of Melbourne.

2000 - 2008. Research Fellow then Lecturer. Nottingham Fuel and Energy Centre, School of Chemical and Environmental Engineering, The University of Nottingham, UK.

2009 - 2018. Lecturer then Senior Lecturer, School of Chemical Engineering, The University of Queensland.

2019 - present. Associate Professor, School of Chemical Engineering, The University of Queensland.

My research interests are in energy and resources, including coal science, gas recovery, and sustainable mineral processing with a strong interest in developing new technologies to solve major issues. I develop new experimental/analytical capabilities and innovative approaches to provide new knowledge and novel insights that can help Australian industries maintain and extend their competitiveness in world markets. I also develop novel process schemes by manipulating solution equilibria and are currently focused on developing new mineral processes that include CO2 sequestration.

Main themes:

Metallurgical Coal Carbonisation

I have pioneered the use of high temperature oscillatory shear rheometry to characterise the microstructure of coal during pyrolysis/carbonisation as it transforms into coke (an essential porous carbon material used for steel-making). I obtained real mechanical properties of the plastic phase that forms and studied viscoelastic thresholds for bubble nucleation, growth and coalescence which enabled me to develop a hypothesis for a process problem known as high oven wall pressure. The knowledge base created from this research has paved the way for better models to predict oven wall pressure and elucidated clever ways to control pressure through blending.

This led to an ambitious new focus to develop a mechanistic model for coke strength that would reveal why some coals are not well predicted and how the value of a coal could be improved through blending. I combine rheometry and X-ray micro-CT analysis to reveal the physical mechanisms by which the pore structure of coke forms and how its features contribute to coke strength. The approaches taken have application in other fields, particularly where the curing of a foam occurs.

Significance: Coal is the 2nd biggest export earner for Australia, whereby the majority is metallurgical (met) coal used to make coke, and Australia is currently the largest exporter of met coal in the world. My research is used to ensure Australia remains at the forefront by enabling better predictions on the behaviour of different coals and providing new opportunities for the marketing of Australian coals.

Main collaborators: BHP, Anglo American, Rio Tinto, Peabody, Vale, The University of Newcastle (Aus), CSIRO, School of Earth Sciences (UQ).

Novel stimulation methods for enhanced methane recovery from coal seams

Methane is a ‘cleaner’ fuel than coal because it is hydrogen-rich and can be burned in high efficiency combined cycles. Coal deposits in eastern Australia have enormous amounts of adsorbed methane (known as coal seam gas or coalbed methane) which has given rise to a fast growing industry whereby the methane is extracted, liquefied (LNG), and exported overseas. Extraction depends on the permeability of the coal seam. The most commonly used technology for increasing permeability is hydraulic fracturing, which originates from the conventional oil/gas industry where sandstone is the usual source rock. The structural properties dictating permeability for coal is different, whereby coal is already highly cleated due to the shrinkage process that occurs during formation. There could be a missed opportunity, whereby instead of creating a new fracture network, flow through the existing cleat network could be enhanced through dissolution of the minerals within the cleats and etching of cleat surfaces.

I have developed new laboratory and analytical capabilities to study the chemical and physical effects caused during chemical injection, including X-ray micro-CT analysis combined with pore characterisation and flow simulation (using GEODICT) to explain the permeability changes observed in laboratory injection tests. Approaches taken have application in other areas, including predicting flow behaviour of CO2 through subsurface rock.

Significance: Liquefied Natural Gas (LNG) is the 5th biggest export earner for Australia, whereby 25% comes from Queensland. Industry is currently targeting regions where gas is easy to extract, and the challenge is to develop new technologies for increasing permeability in other regions. Chemical stimulation has the potential to increase permeability in a predictable manner and may play a crucial role in the growth of the CSG industry and assist it in competing with other supply regions.

Main collaborators: Santos, Origin Energy, Arrow Energy, QGC, Centre for Coal Seam Gas (UQ), School of Earth Sciences (UQ).

Sequestration of CO2 as stable mineral carbonates

Mineral carbonates are known to be stable for millions of years and so conversion of CO2 emissions to solid carbonate is an attractive solution. There is a major technological barrier preventing development of a commercially viable process, which is associated with the difference in pH between carbonate ion formation and mineral carbonate precipitation. My background in manipulating solution equilibria to achieve desired effects led me to establish a novel chemical route for making Mg-carbonates from CO2 and Mg-silicates involving a regenerable buffer to control ionic equilibria and enable a pH commensurate for carbonates to precipitate. Given that Mg-silicates can contain Ni the process can be aligned with the current process for Ni recovery.

Significance: Technologies to mitigate against CO2 emissions are of unparalled importance. One of the major challenges is keeping the cost low. Using clever chemistry and combining CO2 sequestration with existing mineral processing operations that produce valuable commodities could be a viable way of allowing it to work commercially.

Main collaborator: Sirius Minerals.

Treatment of spent pot-lining (SPL)

A chemical leaching scheme for the treatment of spent pot-lining (a hazardous waste currently going to landfill) has been developed. Aluminium cations (Al3+) are used at low temperatures and pressures to recover fluoride as AlF2OH which can be converted to AlF3 for sale back to smelters. Graphite is also recovered. Current efforts are focused on the AlF2OH crystallisation step, where particle size and purity must be optimised.

Production of Ultra-Clean Coal (UCC)

A chemical leaching scheme for the production of UCC has been developed, whereby the mineral level in coal is reduced to below 0.1 wt%, chemical reagents are recycled, and a pure silica co-product is generated. The main application of UCC is direct firing in gas turbines, which would enable coal to be burned in high efficiency cycles such as the natural gas combined cycle (NGCC). The UCC could also supplement petcoke used for the production of carbon anodes in the aluminium smelting industry. Current efforts are focused on reducing the energy requirements, which is the main barrier to commercialisation.

Qualifications

  • Bachelor of Engineering, University of Melbourne
  • Doctor of Philosophy in Chemical Engineering, University of Melbourne

Publications

View all Publications

Supervision

View all Supervision

Available Projects

View all Available Projects

Publications

Journal Article

Conference Publication

Grants (Administered at UQ)

PhD and MPhil Supervision

Current Supervision

  • Doctor Philosophy — Principal Advisor

  • Doctor Philosophy — Principal Advisor

    Other advisors:

  • Doctor Philosophy — Associate Advisor

Completed Supervision

Possible Research Projects

Note for students: The possible research projects listed on this page may not be comprehensive or up to date. Always feel free to contact the staff for more information, and also with your own research ideas.