Phase transformation of iron-based catalyst at coal liquefaction

WU Yan; ZHAO Peng; MAO Xuefeng

doi:10.13225/j.cnki.jccs.2017.1118

Abstract：In order to study the action mechanism and the principle of active phase regulation on coal liquefaction catalyst,the phase transition process of Fe2O3 in coal liquefaction had been investigated.The study was performed using X-ray powder diffractometer (XRD),saturate magnetization and scanning electron microscope (SEM).The Fe2O3 was identified and there was no FeS2 because S element was insufficient in the system.Due to the sufficient H element,the Fe2O3 had been reduced to Fe3O4.The temperature experiment results showed that Fe2O3 was vulcanized into two crystal forms of Fe7S8 (monoclinic and trigonal system) at 400 ℃,and the Fe7S8 was desulfurized into Fe9S1o and Feo.95S.The pyrrhotite was desulfurized to FeS continuously when temperature risen to 420 ℃ and 440 ℃.The time experiment results showed that the velocity of Fe7S8 transformed to Fe9S10 was slower than Fe9S10 decomposition in the system when the reaction time was 0 min at 420 ℃.Fe7S8 decomposed to produce lower S/Fe pyrrhotites at a uniform speed when the reactions continue.More stable FeS was generated when the reaction time was 90 min.The asphahene yield increased because catalyst capacity decreased.The SEM photos showed that there were long strip of macromolecular condensation polymers in the system.The atmosphere experiments showed that the same kind of iron sulfide was generated in nitrogen and hydrogen,but Fe7S8 generated in nitrogen was less than in hydrogen