摘要
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Fe_2O_3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Fe_2O_3残留且未发现FeS_2,可知体系中S元素不足;因H元素充足,部分Fe_2O_3被还原为Fe_3O_4。温度条件实验结果显示:400℃时,Fe_2O_3已被硫化生成两种晶形的Fe_7S_8(单斜晶系和三方晶系),且部分Fe_7S_8脱硫生成六方晶系的Fe_9S_(10),Fe_(0.95)S;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Fe_7S_8脱硫生成Fe_9S_(10)的速度低于Fe_9S_(10)分解速度,所以在XRD谱图中未发现Fe_9S_(10)的谱峰。随反应时间延长,体系中的亚铁磁性Fe_7S_8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Fe_7S_8较少。
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 Fe9S（10） and Fe（0.95）S.The pyrrhotite was desulfurized to Fe S continuously when temperature risen to 420 ℃ and 440 ℃.The time experiment results showed that the velocity of Fe7S8 transformed to Fe9S（10） was slower than Fe9S（10） 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 Fe S 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 macromolecularcondensation 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
作者
吴艳
赵鹏
毛学锋
WU Yan;ZHAO Peng;MAO Xuefeng(Research Institute of Coal Chemistry, China Coal Research Institute, Beijing 100013, China;State Key Laboratory of Coal Mining and Clean Utiliza- tion（ China Coal Research Institute） ,Beijing 100013 ,China)
出处
《煤炭学报》
EI
CAS
CSCD
北大核心
2018年第5期1448-1454,共7页
Journal of China Coal Society
基金
国家重点研发计划资助项目(2016YFB0600305-3)
NSFC-山西省煤基低碳联合基金资助项目(U1610221)
北京市科技计划资助项目(Z161100002616038)
关键词
煤直接液化
铁系催化剂
相变
coal direct liquefaction
iron-based catalyst
phase transformation
