Effect of coal particle size on the coal hydrogenation reaction — In relation to the plasticity of coal

The effect of coal particle size on the catalytic hydrogenation of dry coal was investigated for three Hokkaido coals (Japan) of different ranks. It was found that the effect of coal particle size on conversion is dependent on coal rank. A greater difference in conversion with respect to coal particle size is noticed for coals of lower carbon content. The physical appearance of the products in the autoclave after the reaction suggests that the effect of particle size on conversion is dependent on the plastic properties of the heated coal sample. When the reaction proceeds with coal in the plastic state, the effect of particle size is small. As indicated by the product distribution, the plastic properties of a coal sample are related to the yield of asphaltene (hexane insoluble/benzene solubles) and/or the structural parts of original coal which yield asphaltene.