高岭土合成沸石分子筛的研究进展

高岭土的化学成分主要为硅和铝,可以作为硅铝源,用于沸石分子筛的合成过程.与以常规的凝胶法合成的沸石相比,以高岭土为原料合成的沸石分子筛以及催化剂,在沸石晶粒大小、水热稳定性、活性和抗重金属性能等方面具有独特的特点,且由于高岭土价格低廉、合成沸石成本低,因此在学术界和企业界引起人们的开发研究兴趣.本文对以高岭土为原料合成沸石分子筛的机理及其研究进展进行了综述.     

稀土形态与FCC催化剂性能关系的研究

采用IR羟基表征、XRD、微型和小型反应器等手段研究了不同形态稀土在FCC催化剂中的应用.实验结果表明,在分子筛制备过程中以沉淀方式引入的稀土,部分以独立相形式存在,具有抗钒污染的性能,对催化剂活性和裂化产物分布影响不大,这与以交换方式引入分子筛中的稀土对催化剂的影响不同.     

稀土和磷改性对裂化催化剂反应性能的影响

我们采用稀土以及稀土和磷两种方式对Y型沸石表面进行修饰，NH3-TPD测试表明稀土和磷复合改性Y沸石(P—RE—USY)的酸性分布更集中在中强酸范围．在固定床和提升管装置上评价了含有P—RE-USY沸石催化剂的反应性能．经过稀土和磷复合改性，增强了沸石孔道的酸性中心，而表面活性中心在磷和稀土相互作用的改性中得以减少和弱化．这种修饰作用引导更多的烃分子进入沸石孔道中进行反应，减少了烃分子通过表面反应形成大量烯烃分子的几率．同时，由于烯烃的降低不完全来自二次氢转移反应的饱和过程，所以，适度降低二次反应有效地减少了中间馏分油的裂解，提高了柴油收率．     

高岭土基质与重金属的相互作用

The phase transformation of kaolin in the presence of 1%～5% vanadium had been investigated. The results indicated that vanadium mullite emerged at 660～700℃which was at least 400℃ lower than conventional mullite formation temperature, and a chemical reaction between kaolin and vanadium took place obviously. The reaction of vanadium mullite formation could be described as a process of low melting vanadium kaolin eutectic transition.In addition, the unit cell volume of vanadium mullite was found increased with the increment of vanadium content, which could be deduced that vanadium incorporated into mullites' framework and was therefore passivated. Furthermore, in comparison with hydro kaolin, modified kaolin—PAL and CLS reacted fast with vanadium to form more mullite and CLS could even reacted with nickel to form a rather stable compound of NiAl 10 O 16 , and therefore protected zeolite in cracking catalysts against the heavy metal poisoning effectively.     

新型催化裂化助辛剂的研制

采用最新开发的粘结剂专利技术,制备了新型的LEO催化裂化助剂,并在小型固定床和中型提升管上进行了评价,结果表明当助剂加入量为2%～3%时,满足了轻质油损失较少和提高辛烷值的要求.