Fluidised bed gasification of low grade

To cope with increasing electricity demand, South Africa will need to install approximately 1000 MW of generating capacity per year for the foreseeable future. Whilst there is increasing pressure to adopt non-fossil fuel electricity generating technologies, it is a fact that South Africa will continue to exploit its abundant coal reserves. The challenge, therefore, is to utilise the coal as efficiently as possible, in order to reduce carbon dioxide emissions. This paper describes an on-going investigation into one potential Clean Coal Technology (CCT), namely fluidised bed gasification. Coal gasification holds the potential benefits of increased efficiency, reduced water consumption and co-production of liquid and gaseous fuels and chemicals. A suite of five South African coals has been identified as being possible fuels for power stations which would operate for three or four decades, towards the middle of this century. These coals are being subjected to thermogravimetric analysis (TGA) to ascertain their reactivity under gasification conditions. Further, pilot scale gasification trials will be carried out on two of these coals. The objective is to rank the coals in terms of suitability for gasification, and to ascertain if TGA analysis can give an accurate prediction of actual performance in a gasifier.