Coal liquefaction and catalysis

There appears to be considerable potential for improving the processing and economics of direct coal liquefaction through the development and application of highly dispersed catalysts, where the aims are to promote the process of primary coal dissolution, and produce a solubilized product that can be readily upgraded in a second stage over a supported catalyst. Dispersed catalysts may also help to realize the potential of using cheap low-rank coals as liquefaction feedstocks by increasing the low rate and extent of conversion that are normally obtained. While iron based catalysts lack the high activity associated with other metals, such as molybdenum, their low cost has attracted considerable attention. Research to increase the activity of iron based catalysts focuses on decreasing the particle size, increasing catalyst dispersion, modifying the catalyst composition by the addition of promoters, or a combination of these strategies. To date, most of the work has been conducted on a laboratory scale. Several of the more promising lines of research are discussed.