催化裂化装置沉降器内结焦物的基本特性分析及其油气流动对结焦形成过程的影响

 通过对催化裂化装置(FCCU)沉降器内结焦物的微观组织结构和密度的分析, 考察了两者之间的内在关系,探讨了油气流动对结焦过程的影响. 油气的流动不仅起到输送油气液滴和催化剂颗粒的作用,油气的流动状态还影响油气液滴和催化剂颗粒之间的相互作用,影响它们在器壁的沉积形式,使焦体与催化剂颗粒结合方式具有多样性,焦体与催化剂颗粒的比例关系和结焦中催化剂颗粒粒度的分布发生变化; 从微观结构上看,是结焦的致密性发生变化, 从宏观上看,是结焦的密度发生变化. 根据油气流动速度的大小可将沉降器分为3类区域,各区域的结焦情况不同. 在油气静止区域,催化剂颗粒沉降堆积在固体表面上, 结焦中主要是催化剂,焦体比例少,结焦组织疏松,密度低; 在油气流动区域, 液滴与催化剂颗粒扩散沉积在固体表面上,结焦中焦体所占比例大,催化剂颗粒少且粒径小,结焦质地致密,密度高.

CHARACTERISTICS OF COKE IN FCCU DISENGAGER AND EFFECT OF OIL GAS FLOW ON COKE FORMATION PROCESS

The microstructures and density of the industrial coke samples from the disengager of fluidized catalytic cracking unit（FCCU）, and the relation between them were analyzed. The coke formation mechanism and the effect of oil gas flow on coke forming process were discussed. The oil gas flow not only carries the droplets and catalyst particles, but also affect their integration and deposition on the wall of disengager, further influence the composition and the density of coke, which means that the coke compactness changed from the view of microstructure, and the coke density changed from the view of macrostructure. According to the velocity of oil gas flow, there were three zones in the disengager, in which the compositions and structures of coke were various. In the dead zone, the falling oil droplets and catalyst particles were accumulated together on the surface of the equipment and converted into coke with porous and low density, containing lots of catalyst particles. In the flowing zone, the moving oil droplets and catalyst particles were deposited on the surface of the equipment and converted into coke with nonporous and high density, containing a few small catalyst particles and much compact coke.