Abstract: The Reynolds stress model was used to simulate gas-solids flow field of built-in fourth stage separation cyclone system in FCCU. Cross flow existed at the bottom of the dust hopper in the cyclone separator, which was not favorable for particle discharge. Although blowdown on the top of the dust storage tank could help separator discharge, it also increased the chance of particles escaping from the balance tube, lowering separation efficiency. The movement trajectory of particles in the system included trapped in the dust hopper of the dust storage tank, escaping from the vortex finder and the balance tube. In order to reduce particles escaping from the balance tube, adding a cone baffle in the dust storage tank could be an effective way. Particle concentration was higher at the top of the annular space and the bottom of the dust hopper, causing wall wear out. The built-in fourth stage separation cyclone system had an advantage of resolving catalyst loss.

Key words: FCC, fourth stage cyclone separation system, gas-solids two-phase flow, numerical simulation

摘要： 通过数值模拟的方法,采用RSM湍流模型对FCC内置式四旋分离系统内气固两相流场进行了研究.研究表明,四旋灰斗底部存在错流,不利于排料;储料罐顶部平衡管泄气有利于四旋排料,但同时增加了颗粒逃逸的概率,降低分离系统效率;分离系统内颗粒运动轨迹包括灰斗捕集、排气管逃逸及平衡管逃逸,控制颗粒在平衡管逃逸可通过在储料罐内添加锥形挡板结构实现;四旋环形空间顶部与灰斗底部锥段颗粒浓度较高,易对四旋内壁产生磨损;内置式四旋分离系统优点在于不存在催化剂跑损问题.

关键词: FCC, 四旋分离系统, 气固两相流, 数值模拟