ABSTRACT
Better characterisation of coal volatile yields under rapid heating conditions could improve fuel matching for existing plant, leading to improved overall performance, and also assist in the development of advanced clean combustion technologies. The relative merits of entrained flow and captive sample techniques for routine coal characterisation under rapid heating are discussed. Although the former can apply conditions more representative of PF combustion, volatile yield measurements are likely to be easier and more accurate in the latter. A version of the well known wire-mesh captive sample reactor is described which dispenses with fine thermocouples for temperature measurement and is therefore easier to use on a routine basis. Results obtained in this apparatus for a variety of coals are presented. These show that the R factor, the ratio between yields under rapid heating conditions and the proximate VM content, can vary significantly between coals. A brief comparison with results from drop tube reactors indicates approximately similar trends.
