Comprehensive Conventional Analysis of Southern Hemisphere Coal Chars of Different Ranks for Fixed Bed Gasification
In this study, the physical and chemical changes accompanied in the coal to char transition were examined by conventional and Fourier Transform infrared spectroscopy (FTIR) techniques. Six coals (lignite to anthracite) o≤f 75 μm were acid washed, and subjected to a slow heating rate of 20 oC/min from 450 to 700 oC at atmospheric atmosphere. The chars were characterized by physical, chemical and petrographic evaluations. The coals were low rank C lignite (Rov = 0.31), low rank B sub-bituminous (Rov = 0.47), medium rank C bituminous (Rov = 0.73 for high volatile and Rov = 0.78 for low volatile), high rank C semi-anthracite (Rov = 2.48) and high rank B anthracite (Rov = 3.26) respectively. Char properties determined by conventional technique (proximate, ultimate and calorific value) and FTIR revealed correlations of the chemical structural changes during the coal to char transition. Unique relationships between the fuel ratio and other coal properties (H/C atomic ratio and aromaticity) were established. The fuel ratio was determined to be in the range of 1.9 – 21.0 for lignite; 3.4 – 20.3 for subbituminous; 5.5 – 24.0 for bituminous; 11.6 – 29.6 for semi-anthracite and 16.5 – 27.8 for anthracite.
