Raman spectroscopy of coal macerals and fluidized bed char morphotypes

Raman spectroscopy analyses were carried out on macerals from a set of coals with increasing rank and their corresponding char morphotypes in order to improve the understanding of the structure of coal char produced in a fluidized bed reactor. The Raman parameters obtained on collotelinite and fusinite are different from those obtained on the corresponding fused char and fusinoid morphotypes. The highest differences occur between collotelinite and corresponding fused chars, suggesting that major structural changes occur in collotelinite during pyrolysis, while those occurring in fusinite are less pronounced. Raman parameters of the different fused char and fusinoid portions are similar, suggesting that the heat treatment enhanced the formation of similar structures. However, the fused char portions not only display different optical patterns from fusinoid chars but also have slightly higher reflectance. (C) 2012 Elsevier Ltd. All rights reserved.