Investigation of Different Coke Samples Adhering to Cyclone Walls of a Commercial RFCC Reactor

作     者：Li Xiaoman Song Jianfei Sun Guogang Yan Chaoyu Wei Yaodong 

作者机构：State Key Laboratory of Heavy Oil Processing China University of Petroleum 

出 版 物：《China Petroleum Processing & Petrochemical Technology》 (中国炼油与石油化工（英文版）)

年 卷 期：2016年第18卷第1期

页      面：8-14页

核心收录：

学科分类：080706[工学-化工过程机械] 08[工学] 0807[工学-动力工程及工程热物理] 

基　　金：financial support from the National Natural Science Foundation of China (No. 21176250  No. 21566038) 

主　　题：FCC reactor cyclone coke formation microstructure characteristics 

摘      要：The microstructure and properties of the coke samples collected from 4 different wall regions of the cyclone in the reactor of a residue fluid catalytic cracking unit(RFCCU) were analyzed by using the scanning-electron microscope(SEM), and the possible coke formation processes were investigated as well. The results showed that some of the heavy nonvolatile oil droplets entrained in the flowing oil and gas mixture could possibly deposit or collide on the walls by gravity settling or turbulence diffusion, and then were gradually carbonized into solid coke by condensing and polymerization along with dehydrogenation. Meanwhile some of fine catalyst particles also built up and integrated into the solid coke. The coke can be classified into two types, namely, the hard coke and the soft coke, according to its property, composition and microstructure. The soft coke is formed in the oil and gas mixture s stagnant region where the oil droplets and catalyst particles are freely settled on the wall. The soft coke appears to be loose and contains lots of large catalyst particles. However, the hard coke is formed in the oil and gas mixture s flowing region where the oil droplets and catalyst particles diffuse towards the wall. This kind of coke is nonporous and very hard, which contains a few fine catalyst particles. Therefore, it is clear that the oil and gas mixture not only carries the oil droplets and catalyst particles, but also has the effects on their deposition on the wall, which can influence the composition and characteristics of deposited coke.