DETERMINATION OF RAPID HEATING VOLATILE MATTER CONTENTS AS A ROUTINE TEST

Better characterisation of coal volatile yields under rapid heating co nditions could improve fuel matching for existing plant, leading to im proved overall performance, and also assist in the development of adva nced clean combustion technologies. The relative merits of entrained f low and captive sample techniques for routine coal characterisation un der rapid heating are discussed. Although the former can apply conditi ons 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 dis penses with fine thermocouples for temperature measurement and is ther efore easier to use on a routine basis. Results obtained in this appar atus for a variety of coals are presented. These show that the R facto r, the ratio between yields under rapid heating conditions and the pro ximate VM content, can vary significantly between coals. A brief compa rison with results from drop tube reactors indicates approximately sim ilar trends.