Pyrolysis of South Wales coals: 1. Preliminary thermogravimetric studies

Thermogravimetry (TG) has been applied, in a preliminary investigation, to the pyrolysis of seven samples of South Wales coals varying in rank from bituminous to anthracite. Coal samples (4–10 mg) were investigated within the temperature range 150–900 °C at a heating rate of 80 °C min⁻¹, under a nitrogen atmosphere (40 cm³ min⁻¹). The chart recorder method of collecting data, was replaced by a BBC Model B microcomputer system which included a monitor screen, dual disc drive and a printer. The results indicate a significant increase in the sensitivity, compared with the chart recorder method. In addition, the technique shows promise as an aid in the characterisation of coals, due to the distinct pattern of differential thermogravimetric (DTG) peaks for each sample. It is possible these patterns may be of use in predicting qualities of coal important in gasification processes.