Inorganic constituents of coal liquefaction

Direct coal liquefaction residues from a high volatile bituminous coal and subbituminous coal are examined. Catalyst, temperature, pressure and coal preparation variables are compared for each of the two coals by analyzing the ash percentage of the residue and the inorganic elements present in the residue. The bituminous coal produces high overall conversion efficiencies and high ash content residues with heavy concentrations of inorganic elements when compared to the initial coal. The less efficient subbituminous coal produces lower ash percent residues. Thermo gravimetric analysis, atomic absorption spectrometry, and inductively coupled plasma mass spectrometry are used to determine what inorganic elements carry into the residue and what environmental and operational considerations are needed before the residue is put to further use.