Adsorption and transfer behaviors of hydrogen on Fe1-xS catalysts for direct coal liquefaction

Abstract

Direct coal liquefaction (DCL) is an important and effective method to convert coal into chemicals and fuel oil. Pyrite catalysts play an important role in improving the hydrogenation and liquefaction efficiency of coal. There have been many studies on its active component Fe1-xS in promoting pyrolysis of coal and producing active hydrogen, but studies about the hydrogen migration on Fe1-xS catalyst and the interaction between hydrogen and Fe1-xS catalyst were rarely reported. It is significant to study the hydrogen transfer behaviors on Fe1-xS in DCL and understand the influence of Fe1-xS on the hydrogen migration process. In this study, the chemical adsorption and desorption of hydrogen on Fe1-xS were firstly proved experimentally. After pre-sulfidation of Fe1-xS, the maximum amount of H chemically adsorbed in Fe1-xS is 8.20 mmol/g at 360 °C and 1.5 h. The dehydrogenation of Fe1-xS in an anthracene (ANT) system and re-hydrogenation of that in the hydrogen supply systems, such as H2 and 1,2,3,4-tetrahydronaphthalene (THN), were explored at different experiment conditions, which gave some quantitative results of hydrogen transfer. Particularly, the dehydrogenation of Fe1-xS in the ANT system was analyzed in thermodynamics. The enthalpy of dehydrogenation of Fe1-xS in the ANT system is 117.6 kJ mol−1. The results break the traditional view about Fe1-xS only as a medium for active hydrogen transfer and provides a new perspective for further understanding the hydrogen transfer process.