The North-West University (NWU) reports that the number of post- graduate students participating in its coal research group has increased signifi- cantly since 2009, with more than 35 post- graduate students undertaking research projects in various coal-related study fields, such as gasification, molecular modelling and coal beneficiation.

NWU engineering faculty School of Chemical and Minerals Engineering asso- ciate professor John Bunt, who was seconded to NWU from local energy and chemicals group Sasol, says the investment by Sasol into the coal research group is part of a ten-year skills and competence development programme initiated by Sasol.

“Sasol started the ‘Hub-and-Spoke’ university collaboration programme, which aims to increase the overall skills levels of students by involving them in fundamental coal-reactivity and coal-beneficiation research projects, in 2007,” says Bunt.

The coal research programmes are funded by State-owned power utility Eskom, the South African National Energy Research Institute, South Africa’s National Research Foundation, the Coaltech Research Association and Sasol.

About the Research
Two areas of research related to coal-to- liquids processes, namely coal-reactivity and coal-beneficiation, predominate, says NWU engineering faculty School of Chemical and Minerals Engineering Professor Hein Neomagus, who specialises in coal conversion, membrane technology, kinetics and molecular modelling.

He explains that coal reactivity comprises research into catalytic gasification, combustion, devolatilisation coal extraction, and nitrogen oxide abatement.

He adds that NWU focuses especially on gasification, which is a step in the coal-to-liquids (CTL) process.

“The research done on catalytic gasification enables us to identify the characteristics and reactivity properties of South African coal. By understanding the fundamentals, it might provide some insight to further optimise combustion and gasification processes to ensure minimal impact on the environment,” says Bunt.

Further, the university’s coal-beneficiation research comprises coal dewatering, coal breakage, tomography, induction heating, sequestration and coal-tar research

Coal research at NWU is focused on the fundamental compositions of coal to better understand the mechanisms involved in reactions.

“Understanding mechanisms will enable us to optimise coal processes, making energy more affordable and enabling industries to use energy more effectively,” explains Neomagus.

Student Awards
In 2010, a NWU School of Chemical and Minerals Engineering master’s student, Burgert Hattingh, received an award for the best master’s studies in coal in South Africa.

His study dealt with the carbon dioxide (CO2) gasification of three typical South African coals. The CO2 gasification reaction plays a prominent role in commercial gasifiers, where the carbon in coal is converted to synthesis gas. These gases are then used to generate a wide spectrum of hydrocarbon products.

“My aim with the study was to investi- gate the reaction kinetics and to assess the influence of coal characteristics on the coal’s reactivity,” says Hattingh.

Sasol sponsored Hattingh and his NWU study leaders, Professor Raymond Everson, Neomagus and Bunt.

“The performance can be seen as a great gain for NWU and the faculty as it will establish us as a highly competitive institution in research in coal and coal processing in Southern Africa, as well as internationally,” says Hattingh.

He is currently preparing an article for possible publication in Fuel Processing Technology, an international journal published by Elsevier.

The article also centres on coal, but it deals with another reaction process, called devolatilisation.

Industry Perspective
South Africa has an abundance of coal and, with increasing demands for cheaper energy, the country is likely to continue using it for power generation, says Neomagus.

He adds that the process of using coal for energy has some negative impacts on the environment but, with other resources, such as crude oil nearly depleted, the country will simply have to make do with coal.

However, with coal research being done by some major South African universities and their partners abroad, cleaner and more environment-friendly ways of using coal for energy are a possibility, notes Neomagus.

“Carbon capture and storage might be a future solution to the problem of carbon emissions, but the concept is relatively new to South Africa,” he says.

Further, natural gas can also be harvested for energy use, and interest is increasing in the gas-to-liquids (GTL) refinery process, which uses the same CTL Fischer-Tropsch technology that converts a mixture of carbon monoxide and hydrogen into liquid hydrocarbons.

Even though the GTL technology is expensive, it is more environment friendly than the CTL process.

To subscribe to Mining Weekly's print magazine email subscriptions@creamermedia.co.za or buy now.