http://www.tradeinvestsa.co.za/news/981099.htmWaterberg coal...

http://www.tradeinvestsa.co.za/news/981099.htm

Waterberg coal suitable for fuels and chemicals
Fri, 06 Oct 2006 00:00


Waterberg coal is among the most liquefiable in the world and is also ideal for production of chemicals, says energy expert Prof. Philip Lloyd.

With additional resources of coalbed methane gas, the Waterberg Coal Field therefore has potential for CTL and GTL conversion, and for production from liquid fuels of aromatics such as benzene, toluene and xylene, or simply BTX. These are the basis for a range of plastics South Africa currently imports, such as styrene, PET and urethanes.

Lloyd told a conference held in Lephalale recently to assess the future of the Waterberg Coal Field that the renowned Fischer-Tropsch process used by Sasol to turn coal into liquid fuel and chemicals was not necessarily suitable for application in the Waterberg. Lloyd, who is attached to the Energy Research Centre at the University of Cape Town, highlighted another coal conversion process known as the Bergius process which was developed during the Second World War and which turns some 80% of carbon in coal into useful liquids, a much higher percentage than that yielded by the Fischer-Tropsch process.

The reason why Sasol adopted this process is that coal in the area where it operates is not suitable for the Bergius process. Coal from the Waterberg, however, ‘is one of the best feedstocks in the world’, explains Lloyd.

‘The process needs a special coal,’ he says, adding that coal from the Waterberg’s Grootegeluk mine ‘is very special’; that much of the field’s coal ‘is the most liquefiable in the world’; and that ‘there is great potential in producing chemicals from Grootegeluk coal.

‘The Bergius process has undergone continuous development over the past 60 years,’ says Lloyd. “We now have an excellent idea of the types of products it makes. Importantly, they fall into the class known as aromatics.

‘The South African economy is starved of aromatic feedstocks, which are the raw materials for a host of valuable chemicals, all of which have to be imported at present.’

He adds local manufacturing would be justified if, as seems likely, crude oil prices remain at their current high levels.

Adding more value
Waterberg coal is also well suited to more mundane but nevertheless potentially highly profitable uses, such as making special briquettes from fine coal particles which are often discarded by mines because they are difficult to process.

Briquetting is a process in which fine coal can be formed into lumps – similar to charcoal briquettes – that can be easily handled and transported. The process usually involves mixing fine coal with a binding agent and compressing the mixture into lumps.

However, the cost of binding agents constitutes a major portion of the total production cost. As a result, some briquetting plants have been decommissioned.

Building on international experience, South African research and development institute, the CSIR, is working to develop a ‘binderless briquette’ that could be made for about one third of the cost of conventional briquettes.

The new process involves the application of high pressure to fines, and research indicates that certain coal from the Waterberg’s Grootegeluk mine is well suited to this treatment.

‘Binderless briquetting offers a means to improve the utilisation potential of fine coal from the Waterberg Coal Field,’ a CSIR representative told the conference.