Characterization of Packing Ability of Coke Particles

This work aimed to investigate the reliability of the vibrated bulk density (VBD) test for estimating the void fraction and packing ability of coke particles. VBD is conventionally used in the anode industry to characterize the calcined coke and to determine the required amount of pitch and fine coke. High VBD may be achieved by dense particles while they do not necessarily result in a highly packed bed of particles since packing properties depend on particle shape factors. The apparent density of coke fractions was measured using image analysis. Then the inter-particle void fraction was calculated from the VBD. This void fraction indicates the packing ability of particles. VBD results did not follow the void fraction trend. It is shown that different cokes with equal VBD values might present different inter-particle void fractions. Nor is the VBD necessarily in agreement with intraparticle porosity. It is thus suggested to consider complementary parameters such as shape factors and particle porosity along with the VBD.