Carbon structure transformation during coking of Australian coking coals: Better understanding the coke formation

Carbon structures of coke that are formed during the plastic layer and the semi-coke stage determine the coke strength and reactivity. So far, in the open literature, the evolution and transformation of carbon structures during coking processes and the correlation between the carbon structure parameters to the coke quality and coal properties have not been well understood.

This project aimed to carry out a systematic investigation on the carbon structure transformation from the later stage of the plastic layer to the semi-coke stage during coking using a suite of Australian coking coals from ACARP coal sample bank; to achieve a better understanding on how the carbon structures evolved from the thermoplast and semi-coke and the impacts of carbon structures of coke on coke quality. The partially carbonized samples that include the plastic layers, semi-cokes, and coke samples were prepared using the four kg lab-scale coke oven rig developed at University of Newcastle through which significant advancement in understanding plastic layer formation during coking has been achieved through previous ACARP projects.

The outcomes of this project have advanced our current understanding of coke formation, ie how the carbon structures of coke evolve from the plastic layer and resolidified semi-coke stage. Some progress was made on how the carbon structures are correlated to coke quality and apparent coal properties.

The combination of different analytical techniques used in the project demonstrate an effective method of investigating coking formation and coke quality using premium Australian coking coals. The improved understanding of coke formation through this research provides solid technical support to future ACARP projects. A comprehensive review of carbon structure related research in the open literature is also provided in the Appendix of this report.