ACTIVITY AND CHARACTERIZATION OF COPROCESSING CATALYSTS PRODUCED FROM AN IRON PENTACARBONYL PRECURSOR

It is generally believed that highly dispersed catalysts are very effective in the conversion of coal to liquids but the effects of dispersion and composition have not been adequately investigated. We chose to study the use of iron pentacarbonyl, Fe(CO)5, to produce a highly dispersed catalyst in situ in the coprocessing of Illinois No. 6 coal and Maya ATB residuum. The activity of the catalyst produced from this precursor has been investigated, and its particle size and composition were measured by use of X-ray diffraction, Mössbauer spectroscopy, computer-controlled scanning electron microscopy (CCSEM), and transmission electron microscopy (TEM). Use of 0.5 wt % Fe added as Fe(CO)s resulted in an increase in coal conversion to methylene chloride solubles from 39% to 82%. The Fe(CO)5 precursor decomposed in the reactor to produce a mixture of highly dispersed pyrrhotite (Fe1-XS), Fe3C, and other iron compounds. However, with time at reaction conditions, 95% of the iron was converted to Fe1-XS. The pyrrhotite particles formed in the initial stages of reaction had a mean crystallite size of 12 nm when measured by use of X-ray diffraction line broadening; the small particle sizes were confirmed by TEM, CCSEM, and Mössbauer studies. © 1990, American Chemical Society. All rights reserved.