MechChem Africa talks to Dawie van Vuuren, president of the South African Institution of Chemical Engineers (SAIChE), about his experience of the industry and his views of chemical engineering as a career choice.
“I started my career at CSIR and have worked here, although not continuously, for 35 years in total,” says Van Vuuren. “ I received my chemical engineering degree from Pretoria University in 1976 and began my career here as part of my National Service,” he tells MechChem Africa. Qualification wise, Van Vuuren also holds an MSc from Wits and a PhD from Pretoria University, awarded for a thesis entitled, ‘In search of low cost titanium’.
“Like many chemical engineers of my generation, I was initially involved in synthetic fuels and the Fischer Tropsch process – and many of my team members ended up joining Sasol. I worked on slurry-bed Fischer Tropsch synthesis and I played a role in the initial work of Sasol to develop this process,” Van Vuuren relates, adding that the slurry bed process is now in use on Sasol’s Qatar gas-to-liquids plant.
In principle, the Fischer Tropsch processes carbon monoxide (CO) and hydrogen (H2) – which come from the gasification of coal or more directly from natural gas (CH4) – to make inter alia longer-chain alkane-based liquid fuels such as diesel.
“Sasol 2 and 3 use fluidised bed reactors with all of the reaction products in gaseous phase. These are then condensed and distilled. By using lower temperatures heavier components, such as oily and diesel-like stock, can be produced in fixed or slurry bed reactors,” he explains.
A slurry-bed reactor uses molten wax in which the catalysts are suspended. Describing the reaction, Van Vuuren says: “basically CO and H2 dissolve in the molten wax, which, via the catalysts, react to form more wax and other products.”
Related technologies in Van Vuuren’s experience include energy technologies. “The CSIR has a boiler called the National Fluidised Bed Combustor (NFBC) that can produce 10 t of steam per hour. I was not directly involved in this research, but the team that reported to me for a time designed several commercial fluidised combustion units for a variety of different applications. I also got involved in coal briquetting, gasification, calcination and drying, along with some minerals reduction investigations,” he recalls.
In 1993 Van Vuuren joined AECI in Modderfontein, where he worked for five years. “AECI was a wonderful company to work for and I thoroughly enjoyed my time there. It was there that I began to learn about titanium, starting with titanium effluent treatment for a titanium dioxide pigment plant,” he continues. “I was also involved in phosphoric acid purification, also fascinating, and solid waste treatment of waste fly-ash.
“Unfortunately, AECI decided to close down its engineering department in Modderfontein, so I rejoined the CSIR and became involved in titanium dioxide (TiO2) recovery from waste slag. On the road to Middelburg, is a ...