Catalysis in direct coal liquefaction: status and directions for research

The economic viability and operability of processes to convert coals to useful liquid products is contingent upon the development and application of effective catalysts. New and improved catalysts can lead to more favorable process economics by increasing the rate of conversion and the selectivity to the desired products and by allowing operation at reduced temperatures and pressures. The processes of primary coal dissolution and coal liquids upgrading are distinguished. The status and limitations of catalysts used to promote these reactions are discussed together with approaches which could lead to the development of improved and novel catalysts.