煤加氢液化铁催化剂的穆斯堡尔谱研究——Ⅱ.氧化铁在不同反应条件下的转化及催化活性

MOSSBAUER SPECTROSCOPIC STUDY OF IRON CATALYST IN COAL HYDROLIQUEFACTION——Ⅱ. ON THE TRANSFORMATION AND THE HYDROGENATION ACTIVITY OF FERRIC OXIDE UNDER VARIOUS REACTION CONDITIONS

本文用穆斯堡尔谱学方法跟踪氧化铁催化剂在褐煤液化中随时间的演变过程,同时考察它们在不同S/Fe比系列和不同温度系列中的活性组分及其催化活性。此外,还就超细颗粒进行了探讨。

In the hydroliquefaction lignite, ^(57)Fe Mossbauer spectra of solid residues with an original S/Fe atomic ratio of 0.25, and sampled at different time intervals showed that about 90% of the α-Fe_2O_3 was reduced to Fe_3O_4 and the other 10% was reduced to Fe_(1-x)S and then to Fe-S superparamagnetic phase (SPM). The dominant active Fe-bearing phase which is responsible for enhancing the liquefaction yield is Fe_3O_4 spinel when the original S/Fe atomic ratio is less than 0.25 and is non-stoichiometric hexagonal pyrrhotite Fe_(1-x)S when the ratio is equal to 2.5. The pyrrhotite posseses significantly higher catalytic activity than magnetite. Increase in reaction temperature results in finer catalyst grains and therefore enhances the conversion of the coal to liquid products.