COAL STRUCTURE - INFERENCES FROM CATALYTIC-HYDROGENATION

The early stages of low-temperature catalytic hydrogenation were studi ed with the aim of following changes in the macromolecular network com ponent of coal during catalysed hydropyrolysis/hydroliquefaction. Reac tions were carried out using a subbituminous coal in the presence of M oS2 at 15 MPa H-2 and 300-450-degrees-C in a tubing bomb reactor and a swept fixed-bed reactor. The changes in the coal structural network w ere characterized by volumetric swelling ratios in pyridine, infrared spectroscopy and solid-state nuclear magnetic resonance, and the miner al matter content was determined by low-temperature ashing. The oils w ere analysed by chromatography. The use of two different reactors allo wed the effect of the hydrogenation system on the coal network structu re to be assessed. To infer information on coal structure, the fixed-b ed reactor is preferable because retrogressive reactions are minimized . However, in the tubing bomb the hydrogenation is deeper, and less se vere conditions are needed to obtain high yields of conversion product s.