Abstract:

The characteristics of slip velocity between gas and solid in a short-contact cyclone FCC reactor was simulated using the Eulerian-Eulerian two fluid model, especially about radial distribution of the tangential slip velocity between gas and solid as well as its dependence on operational and physical parameters in the separation chamber. Simulation results showed that the tangential slip velocity between gas and solid had a two-humped distribution in the radial direction. With increase of the inlet gas velocity or decrease of the ratio of catalyst to gas, the tangential slip velocity between gas and solid weakened but the tangential velocity of solid particles enhanced, which would strengthen the centrifugal force on particles and improve the gas-solid separation efficiency. The particle density exhibited little influence on radial distribution of the tangential slip velocity between gas and solid. However, when the particle diameters were increased, the dust outlet would easily be clogged which was not conducive to running the reactor for a long cycle of time. Finally, a model of the average cross-section tangential slip velocity between gas and solid was established with no more than ±7.0% difference among model simulations and calculated results.

Key words: short-contact cyclone reactor, separation chamber, slip velocity, simulation, separation, model

摘要：

利用欧拉-欧拉双流体模型对短接触旋流反应器分离腔内气固滑移特性进行了数值模拟，主要研究了切向气固滑移速度的分布规律，并考察了操作参数和物性参数对分离腔内切向滑移速度的影响。计算结果表明，分离腔内切向气固滑移速度沿径向呈“驼峰”分布；当气相入口速度增大或者剂气比减小时，切向气固滑移速度变小，颗粒切向速度增大，离心力增大，有利于提高气固分离效率；颗粒密度对切向滑移速度分布影响不大；颗粒粒径较大时，在排尘口易出现堵塞，不利于长周期运行；建立了截面平均切向气固滑移速度计算模型，计算值与模拟结果误差在±7.0%以内。

关键词: 短接触旋流反应器, 分离腔, 滑移速度, 模拟, 分离, 模型