Morphological changes of pulverized coals during their devolatilization
Keywords:
devolatilisation, char type, image analysis, scanning electron microscopyAbstract
The aim of this study was to evaluate the influence of coal rank, temperature and time devolatilization on char morphology. Chars were obtained from three different coals rank at 100, 150 and 300 ms time devolatilisation, 900, 1000 and 1100 ºC temperature, using nitrogen atmosphere and a rate heating of 104 ºCmin-1. Char morphology was observed through image analysis and scanning electron microscopy. It was found that released volatile compounds depended of coal rank and increased with temperature and devolatilisation time. In addition, it was observed that there is a relationship between coal rank, porosity and char half thickness wall. Thus, coal rank and devolatilization temperature increase by increasing the average wall thickness and char particle size. It was also found that plasticity occurred on particle surfaces with closed porosity, as well as agglomeration and fusion between char particles having small particles inside them.
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