化工学报 ›› 2012, Vol. 63 ›› Issue (2): 424-432.DOI: 10.3969/j.issn.0438-1157.2012.02.013

• 流体力学与传递现象 • 上一篇    下一篇

超短接触旋流反应器混合腔内气固混合特性的数值模拟

张玉春,金有海,王振波,马艺   

  1. 中国石油大学(华东)重质油国家重点实验室,山东 青岛 266555
  • 收稿日期:2011-07-04 修回日期:2011-09-05 出版日期:2012-02-05 发布日期:2012-02-05
  • 通讯作者: 张玉春

Numerical simulation on gas-solid mixing characteristics in mixing cavity of quick-contact cyclone reactor

ZHANG Yuchun, WANG Zhenbo,JIN Youhai,MA Yi   

  1. ZHANG Yuchun, WANG Zhenbo,JIN Youhai,MA Yi
  • Received:2011-07-04 Revised:2011-09-05 Online:2012-02-05 Published:2012-02-05

摘要: 采用欧拉双流体模型对超短接触旋流反应器内的气固两相流场进行了数值模拟,主要研究了混合腔内固相的体积分数分布情况。计算结果表明:混合腔内的气流在切向进气的作用下得到了一定的混合加速效果,切向的高速射流有效地缩短了气固停留时间,保证短接触反应效果。通过对两种不同混合腔结构反应器的对比计算发现,在相同入口速度条件下结构2(切向进气管位于混合腔顶部)较结构1(切向进气管位于混合腔下部)气固停留时间短,由于切向气流的迅速作用,增加了混合腔内的湍动强度,使催化剂颗粒迅速有效扩散、增强气固接触效果而更有利于催化裂化反应的进行,更易实现短接触操作要求。计算结果与实验测量结果的比较表明模型能有效地描述超短接触旋流反应器内气固两相流动形态。

关键词: Eulerian模型, 气固两相流, 超短接触旋流反应器, 混合特性

Abstract: Gas-solid two-phase flow of the quick-contact cyclone reactor was simulated with the Eulerian model, especially the volume fraction of solid in the mixing cavity was researched. The results show that tangential gas admission accelerates the gas speed in the mixing cavity, it has a great impact on shortening gas-solid residence time and ensuring short contact reaction effect. For two mixing cavity structures, the second reactor (tangential intake pipes were fixed at the top of the mixing cavity) has a shorter residence time in the same inlet velocity, it is more likely to achieve the short contact requirement. Solid particles of the first reactor (tangential intake pipes were fixed at the bottom of the mixing cavity) spread outward in the mixing cavity from the bottom of the feed inlet, nearly no particle moves to the centre space, the concentration gradient is obvious, then under the action of the tangential flow, solid spread evenly, tangential flow has a beneficial effect on the spreading of solid. In the second reactor, axial feeding contacts with the tangential flow in the mixing cavity at once, under the action of the tangential flow, solid particles are evenly distributed, enhancing the contact effect of gas-solid two-phase. The flow state of gas-solid in the separation cavity of two different structures has no difference, particles gather on the wall of the reactor because of the centrifugal force, and then flow down around a spiral. In a word, turbulent diffusion of tangential gas admission increase turbulent intensity, it has a great beneficial effect on spreading the catalyst particles effectively, enhancing gas-solid contact effect. Due to tangential gas admission, the second reactor is better to FCC reaction because of the solid particles spreading more evenly. The comparison of the numerical results and the experimental results show that the present model is available to describe the flow pattern in the reactor. This work could offer a base for the structure optimization of the quick-contact reactor and improve its efficiency.

Key words: Eulerian model, gas-solid two-phase flow, quick-contact cyclone reactor, mixing characteristics

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