石炭液化用高活性リモナイト触媒の開発 １ 豪州産リモナイトの性状と液化活性

Abstract

The properties of limonite ores in Australia were examined by using powder XRD, Mossbauer spectroscopy and TGA, compared to hematite or pyrite are in relation to the catalytic activity in the direct coal liquefaction. It was found that one limonite (YY) deposited in Yandi mine of BHP Iron Ore, that is called Yandi Yellow, con-sisted of only α-FeOOH with no hematite from the analysis in XPD and Mossbauer spec-troscopy. The H2O/Fe (mol/mol) ratio, which was calculated from the weight loss in TGA, varied from 0.06 for hematite to 0.60 for limonite (YY) depending on the hematite content in limonite ore. Results of preliminary pulverization tests using a planetary mill showed that limonite (YY) could be easily pulverized to sub-micron particle size with a small abrasion of medium ball. The coal conversion in the liquefaction of Yallorn coal was increased with an increase in H2O/Fe ratio of limonite catalyst. It appeared tha H2O/Fe ratio could be one of the most important factors to select the better catalyst among limonite ores. The crystallite size of pyrrhotite (Fe1-xS) formed during the coal liquefaction with limonite (YY) catalyst was smaller than that with other limonite cata-lysts. The residual catalytic activities of CLB-THFI, recycled to the reactor through the bottom recycle mode in BSU experiments, was slightly decreased compared to the fresh catalyst due to a slightly increase in the crystallite size of pyrrhotite. It was con-cluded that limonite (YY) could be advantageously used as a catalyst raw material in the commercial plat for coal liquefaction, due to the low cost of catalyst preparation with finely pulverization as well as a high liquefaction activities to obtain a high oil yield.