Activity testing of fine-particle size, unsupported, iron-based catalysts

摘要

The efficiency of the initial reactions of coal during coal liquefaction will have significant impacts on downstream processing (including catalyst usage, reaction severity, product yields, product quality) and hence on process economics. Reactions that result in compounds with low molecular weights and decreased boiling points are beneficial, whereas retrogressive reactions, which yield higher molecular weight compounds that are refractory to further processing, decrease process efficiency. Likewise, reactions that result in decreased sulfur, nitrogen, and oxygen contents and increased hydrogen contents in the products are beneficial. The use of unsupported fine-particle (<40 nm) catalysts during initial coal processing has the potential to enhance desired reactions and minimize retrogressive reactions. The potential advantages of using fine-particle size catalysts include improved dispersion of the catalyst, improved coal /catalyst contact, and the potential for using low amounts ((le)0.5% based on the weight of coal) of these novel catalysts due to their very high surface areas. These catalysts could be combined with the coal or coal-solvent mixture as either active catalysts or catalyst precursors that would be activated in situ. Several methods of combining catalyst and coal, such as physical mixing or using a catalyst-hydrogen donor slurry, are possible. Ideally the fine-particle catalysts would be inexpensive enough to be disposable.