Generalized Kinetic Model for the Uncatalyzed Hydroliquefaction of Coal

A kinetic model, incorporating dehydrogenation of tetralin, for the liquefaction of coals has been developed and tested with data from a variety of low- and medium-rank coals. The model postulates that coal essentially consists of three lumps. Of these, one dissociates almost instantaneously, the second is characterized by slow internal hydrogen shuttling, and only the third lump requires external hydrogen. The reactivity of each lump does not vary between coals; however, different coals are found to contain different fractions of each lump. The rate of reaction of coal is about 3 orders of magnitude faster than the tetralin dehydrogenation reaction. This study clearly shows that it is not only the solvent's capacity to donate hydrogen but also the rate at which hydrogen is donated that is important in coal liquefaction.