催化裂化装置沉降器内结焦物的基本特性分析及其形成过程的探讨

采用扫描电镜（SEM）和X射线能谱分析仪对催化裂化装置（FCCU）沉降器内结焦物的微观组织结构和成分进行了分析，将结焦物划分为软焦和硬焦。焦的硬度与油气液滴和催化剂颗粒的沉积过程有关，尤其是结焦部位的油气流动方式和催化剂颗粒的运动状态，决定着未汽化的重质油组分液滴和催化剂颗粒的沉积形式和沉积物的构成，从而影响着焦的软硬程度。软焦是催化剂颗粒或油气在油气静止空间以自由沉降和扩散方式堆积在器壁表面而产生的结焦，形成的焦块松散，易粉碎，含催化剂比较多，颗粒粒径比较大，是一种堆积型结焦；而硬焦是油气液滴和细小催化剂颗粒在油气流动状态下，在器壁表面的附面层内以沉积方式粘附在器壁表面形成的结焦，焦块质地坚硬，含催化剂比较少。颗粒粒径细小，足沉积型结焦。还有相当一部分结焦物介于软焦和硬焦之间。

THE CHARACTERISTICS AND FORMATION PROCESS OF COKE IN THE FCCU DISENGAGER

The microstructure and composition of coke from different parts of the FCCU disengager were analyzed by using both scanning-electron microscope(SEM) and X-ray analysis(EDS) methods.The cokes were divided into two kinds,i.e.,soft coke and hard coke based on the analytical results.The rigidity of coke was chiefly affected by the ways of oil droplets and catalyst particles accumulating and/or depositing together during coke formation.The incorporation of oil droplets and catalyst particles and their proportion were controlled by the flow field,which turned to influence the rigidity of coke.The soft coke was formed in the dead zone of the FCCU disengager,where the falling oil droplets and catalyst particles were accumulated together on the surface of the equipment in the way of diffusion and converted into accumulated coke,which was spongy and with catalyst particles as its major part.The hard coke was formed in the flowing zone of the FCCU disengager,where the moving oil droplets and catalyst particles were deposited on the surface of the equipment and converted into the deposited coke which was nonporous and hard,and with less catalyst particles.In fact,most of coke was transition between soft coke and hard coke.