Micro-CT-Based Approaches for Quantifying the Morphology of Pulverized Char Particles

Document Type


Publication Date



American Chemical Society

Source Publication

Energy Fuels

Source ISSN



Morphological analysis of pulverized coal char particles using two-dimensional (2-D) cross-sectional imaging has been widely employed, but its accuracy has not been adequately assessed. In this study, pulverized coal char particles are imaged in three dimensions (3-D) using high-resolution X-ray microcomputed tomography (micro-CT). Particle volume, macropore volume, and macroporosity are measured in three dimensions and analyzed as a function of distance from the particle center using averaging at each radial location. A technique for extracting each particle’s average wall thickness, another morphological parameter used for classification, is also presented based on micro-CT imaging. When applied to pulverized bituminous coal char particles, the micro-CT-based analysis revealed a similar spatial distribution of macroporosity among a population that would typically be classified as containing both group II (mixed porous-solid) and group III (dense) particles. Wall thicknesses determined by micro-CT were generally well predicted by a model representing the particles as thick- and thin-walled cenospheres. Comparisons between 2-D and 3-D techniques reveal significant differences because of the use of just a single cross-sectional image in 2-D approaches. A new method for estimating macroporosity from 2-D imaging, called the cylindrical stacking method, is proposed for cases in which the micro-CT analysis is not feasible.


Energy Fuels, Vol. 33, No. 6 (May 2019): 4826-4834. DOI.