Technical Market Support

Gasification Kinetics of Coke Lumps under Simulated Conventional and H2-Rich Blast Furnace Processes

Technical Market Support » Metallurgical Coal

Published: September 23Project Number: C34061

Get ReportAuthor: Apsara Jayasekara, Behnaz Rahmatmand, Salman Khoshk Rish, Merrick Mahoney, Arash Tahmasebi | The University of Newcastle

The introduction of hydrogen-rich fuels into blast furnace (BF) is identified as a promising approach to reducing the carbon footprint of ironmaking. In this process, injected hydrogen promotes the indirect reduction of the ferrous burden generating excess H2O in the process. Partial replacement of CO/CO2 with H2/H2O is expected to alter the gasification rate and coke degradation mechanism as steam is known as a potent gasifying agent.

The overall objective of this project was to improve the fundamental understanding of the rate and mechanism of coke gasification under the hydrogenenriched BF environment, benchmarked against conventional reaction conditions. This was achieved by conducting a series of tests to obtain gasification kinetics of coke lumps under a controlled CO2/CO/H2/H2O/N2 atmosphere in the temperature range of 900-1200 °C, simulating the region above the cohesive zone of BF, where coke gasification is dominant.

A novel experimental test facility was developed to investigate the gasification reactivity of coke lumps under simulated conventional and H2-rich BF environments. In addition, a modified random pore model (RPM) was developed to study the impact of reaction conditions, initial coke quality, and process parameters such as temperature on the mechanism of coke reactivity and degradation. The developed model took both pore diffusion and interfacial reaction for determining the reaction mechanism; hence, it was an improvement on the previous models reported in the literature.

Three pilot oven cokes were examined in this project, which were generated from coal blends, the blend components of which were sourced from different Australian coal measures. The ash chemistry of the coal blends was controlled at a consistent level, therefore, the variations observed in the gasification reactivity of the cokes were related to the differences in their microstructural and carbon structural properties.

The experimental and modelling work was conducted in two stages.

  • The gasification behaviour of the coke samples was investigated in single gas reaction conditions, i.e., in CO2 and H2O to isolate the impact of the two gases and to develop a base kinetics model.
  • The reactivity of cokes was investigated under simulated conventional and H2-rich BF reaction conditions by controlling CO2/CO/H2/H2O/N2 concentrations in the reaction gas mixture. In this stage, the combined impacts of CO2 and H2O on the coke reactivity were analysed and a more complex kinetics model was developed.

Results showed that the reaction rate of coke with H2O was up to 3.7 times faster than that of CO2. Moreover, the effective diffusion coefficient of H2O was up to 6 times greater than CO2. The combination of a higher reaction rate and diffusion coefficient of H2O significantly reduced the time required to achieve the complete conversion of coke lumps. This effect was exacerbated at elevated temperatures, in particular at above 1100 °C. The reaction temperature was also found to greatly influence the rate-controlling mechanism during gasification, where a shift from chemical reaction-controlled to diffusion-controlled reaction occurred at above 1100 °C.

Moreover, the concentration of H2O in the reaction gas and the initial coke CSR were found to greatly influence the mechanism of reactivity and degradation during gasification under conventional and H2-rich BF conditions. Higher H2O concentrations promoted reaction on the outer surface of coke lumps, while the core remained less consumed. Conversely, gasification under conventional BF conditions took place more volumetrically throughout the porous structure of coke. Using this observation, we postulate that the presence of excess H2O in an H2-rich BF shifts the mechanism of coke gasification from chemical-controlled to diffusion-controlled, where due to the significantly higher reaction rate, the diffusion of reactant to the interior pore structure of coke becomes the rate-limiting factor. The consequence is that under H2-rich BF reaction conditions, coke degrades more at the outer layers while maintaining a stronger core.

Results showed that the surface-promoted reaction in the presence of excess steam was more pronounced in higher CSR cokes, suggesting that with increasing the initial coke quality, gas diffusion becomes the rate-limiting factor. In contrast, lower CSR cokes were found to react and degrade more volumetrically. These observations suggest that a higher CSR coke may be required for an H2-rich BF operation to minimise the structural degradation and that a high CSR coke may have a performance advantage under H2-rich BF conditions.

New knowledge on the mechanism of reactivity and degradation of metallurgical coke under conventional and H2-rich BF reaction conditions has been generated. The project allowed an opportunity to develop unique experimental and modelling tools to evaluate coke reactivity under different blast furnace operation conditions.


Health and safety, productivity and environment initiatives.

Recently Completed Projects

C27045Assessment Of Longwall Mining Induced Connective Fracturing

In underground mines the mining induced permeability change in the o...

C29007Innovative Coal Burst System To Investigate The Influence Of Confinement Loss And Pre-Conditioning On Coal Burst Mechanism

The challenges associated with designing and operating a safe and pr...

C28009Advanced Fracture Propagation Testing Of Coal Measure Rocks Under Dynamic Loading To Replicate Coal Burst Scenario

This project is aimed to address critical challenges regarding enhan...


Open Cut

Safety, productivity and the right to operate are priorities for open cut mine research.

Recently Completed Projects

C28035Topsoil Deficits In Site Rehabilitation Accelerated Transformation Of Spoils To Functional Soils

The incorporation of commercial biological amendments (compost, worm...

C34036Tyre Handler Testing Rig Stage 2: Lifting Trials

Tyre handling is a major source of risk in surface mining operations...

C29052Autonomous Water Pressure Sensors For Spoil Dumps And Dams

The geotechnical integrity and stability of a mine spoil dump or tai...

Open Cut

Coal Preparation

Maximising throughput and yield while minimising costs and emissions.

Recently Completed Projects

C28062Improving Operation And Control Of Centrifugal Dewatering Using A Novel Online Tool

Centrifugal dewatering is one of the main processes used for fine an...

C23045Full Scale Trial Of The REFLUX™ Flotation Cell

A 2 m diameter REFLUX Flotation Cell™ (RFC™) was install...

C34042Impact Of Water Quality In Coal Handling And Preparation Plants

This project evaluated water chemistry impacts on the corrosion rate...

Coal Preparation

Technical Market Support

Market acceptance and emphasising the advantages of Australian coals.

Recently Completed Projects

C34062Improving The Classification Of Microstructure Distribution In Coke CT Images Using Deep Learning And Lineal Path Calculations

This project builds on a number of earlier projects that have helped...

C29071Source Of Variability Of Reactivity Of Coke In The CSR Test

The Coke Strength after Reaction (CSR) test is used worldwide to det...

C33070Update Of Coal Dustiness And Dust Extinction Moisture (DEM) Standard AS4156.6

This project involved assessing the accuracy and precision of a prop...

Technical Market Support

Mine Site Greenhouse Gas Mitigation

Mitigating greenhouse gas emissions from the production of coal.

Recently Completed Projects

C28076Selective Absorption Of Methane By Ionic Liquids (SAMIL)

This third and final stage of this project was the culmination of a ...

C29069Low-Cost Catalyst Materials For Effective VAM Catalytic Oxidation

Application of ventilation air methane (VAM) thermal oxidiser requir...

C23052Novel Stone Dust Looping Process For Ventilation Air Methane Abatement

This multi‐phase project is concerned with the mitigation of m...

Mine Site Greenhouse Gas Mitigation

Low Emission Coal Use

Step-change technologies aimed at reducing greenhouse gas emissions.

Recently Completed Projects

C17060BGasification Of Australian Coals

Four Australian coals were trialled in the Siemens 5 MWth pilot scale ga...

C17060AOxyfuel Technology For Carbon Capture And Storage Critical Clean Coal Technology - Interim Support

The status of oxy-fuel technology for first-generation plant is indicate...

C18007Review Of Underground Coal Gasification

This report consists of a broad review of underground coal gasification,...

Low Emission Coal Use

Mining And The Community

The relationship between mines and the local community.

Recently Completed Projects

C16027Assessing Housing And Labour Market Impacts Of Mining Developments In Bowen Basin Communities

The focus of this ACARP-funded project has been to identify a number...

C22029Understanding And Managing Cumulative Impacts Of Coal Mining And Other Land Uses In Regions With Diversified Economies

The coal industry operates in the context of competing land-uses that sh...

C23016Approval And Planning Assessment Of Black Coal Mines In NSW And Qld: A Review Of Economic Assessment Techniques

This reports on issues surrounding economic assessment and analysis ...

Mining And The Community


National Energy Research,Development & Demonstration Council (NERDDC) reports - pre 1992.

Recently Completed Projects

1609-C1609Self Heating of Spoil Piles from Open Cut Coal Mines

Self Heating of Spoil Piles from Open Cut Coal Mines

1301-C1301Stress Control Methods for Optimised Development...

Stress Control Methods for Optimised Development and Extraction Operations

0033-C1356Commissioned Report: Australian Thermal Coals...

Commissioned Report: Australian Thermal Coals - An Industry Handbook