CAMD Study of Coal Model Molecules. 2. Density Simulation for Four Japanese Coals

The physical densities of previously proposed model structures of four Japanese coals [Tempoku, Taiheiyo, Akabira, and Yubari coals; carbon content (wt %, daf) 71.5, 77.9, 81.2, and 86.7 and physical density (g·cm⁻³) 1.37, 1.27, 1.28, and 1.24, respectively] were calculated using CAMD (computer-aided molecular design) software. The calculated densities (g·cm⁻³) followed the sequence Akabira coal 1.03 < Yubari coal 1.11 < Taiheiyo coal 1.22 < Tempoku coal 1.29, increasing as the carbon content of the coal structures decreased, except for the Akabira coal structure. A modification of the bridge structure in the Akabira coal model afforded a calculated density of 1.15. Thus, the correlation between the carbon contents and the physical densities for the original coals could be reasonably reproduced.