铁酸盐尖晶石催化剂的脉冲反应性能  

STUDIES ON THE REDUCTION BEHAVIOUR AND SURFACE REACTION OF FERRITE SPINEL WITH BUTENE PULSE

作　　者：王继东[1] 宋为民[1] 尹元根[1] 

机构地区：[1]北京化纤工学院化学化工系

出　　处：《物理化学学报》1990年第2期239-245,共7页Acta Physico-Chimica Sinica

基　　金：国家自然科学基金;中国石油化工总公司资助的项目

摘　　要：铁酸盐尖晶石作为工业生产丁二烯的催化剂,自70年代问世以来,已用多种方法对其结构、催化性能、动力学特征、催化机理及其表面结构氧种等作了研究.B-02催化剂在工业反应器中已正常长期运转.为进一步发挥其潜力,还需要更进一步的了解,尤其对在绝热床反应器中高温缺氧情况下的催化状态,还缺乏基本的了解.本文以脉冲反应为主并结合TPR、TPD、XRD和FT-IR方法对与B-20及有关的MgFe_2O_4、α-Fe_2O_3和γ-Fe_2O_3的性能作进一步的考察。In this paper, B-02 catalyst, developed by Yanshan Synthetic Rubber Factoryand used in two large production plants,was investigated by means of pulse techniqueand temperature-programmed techniques,as well as XRD and FT-IR techniques. Threerelated iron compound, magnesium ferrite,hematite, and maghemite,were also studied. XRD showed the presence of two crystallographic phases, viz.,magnesium ferriteand hematite, in the B-02 catalyst. A combination study of the reduction behavior of B-02 was established, compri-sing, in addition to the conventional TPR technique, the pulse reduction and conti-nuous reduction by hydrogen at step temperatures. Evidences were provided to showthat, at 673K, the hematite presented in the B-02 catalyst was reduced to magnetite,while in the region 723-773K, all the Fe (Ⅲ) presented in the catalyst includingspinelic and hematitic, were reduced to Fe (Ⅱ), and above 823K, 1/3 to 1/4 ofthe Fe(Ⅲ) was reduced to metallic iron state. The spinel phase was progressivelydestroyed with increasing reduction extent. Results suggested the presence of three oxygen species on the B-02 and relatedFe-containing compounds: those responsible for the strong retention of butene on thecatalyst (O_a), those responsible for the selective formation of butadiene (O_b), andthose responsible for the carbon dioxide formation (O_c). Under certain conditions,theamount of carbon dioxide desorbed in TPD of retained butene on B-02 catalyst,beingrelated to the O_c species, is a constant for different dosages. As can be seen fromthe cumulative consumption of lattice oxygen in butene pulse reaction, the O_b specieson B-02 catalyst and magnesium ferrite can be further divided into two sub-speciesaccording to their dependences on temperature. Significant amount of oxygen species may be removed from the B-02 catalystwhen the catalyst was subjected to reducing medium. It was shown that the oxygenspecies removed by hydrogen is somewhat different to those removed by butene.Butene reduction appeared to remove more active oxyge

关 键 词：铁酸盐尖晶石 催化剂 脉冲反应 

分 类 号：TQ426.7[化学工程]