Coprocessing of Berguedà lignite with vacuum residue under increasing hydrogen pressure comparison with hydrotreating

Abstract

The influence of initial pressure of hydrogen on the catalytic coprocessing of Berguedà lignite with a vacuum residue of petroleum was studied, using an Fe/γ-Al 2O 3 catalyst. Coal conversion increased with initial hydrogen pressure up to 10 MPa, but there was no significant increase beyond this value. However, oil conversion increased with pressure up to 12 MPa. On the other hand, high pressures markedly decreased gas production, both hydrocarbons and non-hydrocarbons. Maximum coal conversion was reached at lower temperatures when the initial hydrogen pressure increased. These results suggest that the coprocessing occurs with transfer of hydrogen via the aromatic compounds present. In hydrogenation of the vacuum residue in the absence of coal, under the same conditions as for coprocessing, the reaction products were in general more aromatic, but with an important loss of oil fraction. A synergistic interaction occurs when coal and vacuum residue are coprocessed.