PETROGRAPHIC CLASSIFICATION OF SOLID RESIDUES DERIVED FROM THE HYDROGENATION OF BITUMINOUS COALS.

This paper is concerned with the optical study of the physical mechanisms involved in maceral dissolution during coal hydrogenation as well as the properties and morphology of residue constituents ( ″char″ ). Optical studies reveal that residue constituents are formed as a result of incomplete hydrogenation, repolymerization or carbonization. Those coal macerals which pass through the process unreacted or exhibiting only slight morphological alteration are readily identified. Other constituents are related to their precursory macerals by studying low temperature batch hydrogenation residues and are described on the basis of their morphology, relative reflectance, anisotropy, and grain size. The results of these optical studies along with a classification of organic solid residues are tabulated.