为研究煤液化催化剂的作用机制和活性相调控原理,通过X射线粉末衍射、饱和磁化强度及SEM扫描电镜等分析手段,对Fe2O3在煤液化条件下的相变过程进行了研究。在煤液化产物四氢呋喃不溶物样品中鉴别出部分Fe2O3残留且未发现FeS2,可知体系中S元素不足;因H元素充足,部分Fe2O3被还原为Fe3O4。温度条件实验结果显示:400℃时,Fe2O3已被硫化生成两种晶形的Fe7S8（单斜晶系和三方晶系）,且部分Fe7S8脱硫生成六方晶系的Fe9S10,Fe0.95S;当温度升高至420℃和440℃,部分磁黄铁矿继续脱硫生成六方晶系陨硫铁FeS。时间条件试验显示在420℃下,当反应时间为0 min时,体系中Fe7S8脱硫生成Fe9S10的速度低于Fe9S10分解速度,所以在XRD谱图中未发现Fe9S10的谱峰。随反应时间延长,体系中的亚铁磁性Fe7S8匀速分解生成S/Fe原子比更低的磁黄铁矿,当反应时间为90 min时,生成了较多稳定的FeS,此时催化剂促进沥青质加氢裂化的能力下降,煤液化的油收率下降,沥青质产率增加。SEM照片显示体系中出现了长条状的大分子缩聚物。反应气氛实验表明,在氮气和氢气气氛下生成了同样种类的铁硫化物,但氮气气氛下生成的Fe7S8较少。

In order to study the action mechanism and the principle of active phase regulation on coal liquefaction cata- lyst,the phase transition process of Fe2 O3 in coal liquefaction had been investigated. The study was performed using X-ray powder diffractometer (XRD),saturate magnetization and scanning electron microscope (SEM). The Fe2 O3 was identified and there was no FeS2 because S element was insufficient in the system. Due to the sufficient H element,the Fe2 O3 had been reduced to Fe3 O4 . The temperature experiment results showed that Fe2 O3 was vulcanized into two crys- tal forms of Fe7 S8(monoclinic and trigonal system) at 400 ℃ ,and the Fe7 S8 was desulfurized into Fe9 S10 and Fe0. 95 S. The pyrrhotite was desulfurized to FeS continuously when temperature risen to 420 ℃ and 440 ℃ . The time experi- ment results showed that the velocity of Fe7 S8 transformed to Fe9 S10 was slower than Fe9 S10 decomposition in the sys- tem when the reaction time was 0 min at 420 ℃ . Fe7 S8 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 asphaltene yield increased because catalyst capacity decreased. The SEM photos showed that there were long strip of macromolec- ular condensation polymers in the system. The atmosphere experiments showed that the same kind of iron sulfide was generated in nitrogen and hydrogen,but Fe7 S8 generated in nitrogen was less than in hydrogen