A study on combustion of Chinese coals by TA/MS

Thermal behavior and evolution characterization under designed combustion conditions of 13 Chinese coals of different ranks were investigated by means of thermal analysis/mass spectrometry (TA/MS). The experiments were carried out in a synthetic air atmosphere (20% oxygen+80% nitrogen) with a flow rate of 150 ml min(-1) and the samples were heated from 40 up to 1200 degreesC at a constant heating rate of 10 K min(-1). The volatile products and their evolution profiles against the temperature during the combustion were identified through the on-line recorded mass spectra. The results revealed that the whole combustion procedure could be broadly divided into 4 phases and the temperature of the maximum weight loss rate shifted to lower temperatures as the coal rank decreased. In addition to the primary combustion products water and carbon dioxide, fragments with the masses m/z 15, 55-60, 66, 67 and sulphur dioxide (m/z 64) were also found in the mass spectra. (C) 2002 Elsevier Science B.V. All rights reserved.