Valentim, B.Lemos de Sousa, M. J.Abelha, P.Boavida, D.Gulyurtlu, I.2007-05-082011-10-062007-05-082011-10-062006International Journal of Coal Geology. 67 (2006), pp. 202-21167 (2006)http://hdl.handle.net/10284/273During the petrographic study of seven feed coals from different origins, it was found that these coals presented microfeatures such as: material size, shape, weathering, thermally affected particles and contamination. After devolatilization under fluidized bed conditions, some chars presented the consequences of the above mentioned microfeatures, i.e., unreacted coal, unswelled particles, coatings and microstratification. Since the amounts of the microfeatures observed were low (less than 1%), the present study is essentially observational/ descriptional. However, it seems very likely, from the observations that were made, that the occurrence of one or more of these microfeatures in coal, depending on their kind and abundance, may have significant effect on the coal devolatilization.engCoal petrographyMicrofeatures;CharFluidized bed combustionjournal article