工业级MIP提升管反应器气固两相流动特性的数值模拟

Numerical Simulation of the Gas-Solid Two-Phase Flow Characteristics in the Industrial Grade MIP Riser Reactor

以工业上多产异构烷烃催化裂化工艺(MIP)装置的提升管反应器为研究对象,采用欧拉-欧拉双流体模型对反应器的气固两相流动行为进行三维冷态数值模拟。采用计算流体力学(CFD)模拟方法分析了预提升段、一反段和二反段的气固流动特性,并对比了催化剂颗粒入口的质量流量与原料油入口的质量流量之比(剂油比)分别为6、7、8时反应器内的流动特性。模拟结果表明MIP提升管反应器内存在典型的非均匀流动特点。随着剂油比的增加,催化剂颗粒的轴向速度降低,固相体积分数增加。

Maximizing iso-paraffins(MIP) process utilizes the technique of linking two reaction zones in series to effectively improve the gasoline quality. Aiming at the fluid catalytic cracking(FCC) riser reactor in MIP process, this paper considers the three-dimensional cold simulation problem of the flow behavior of gas-solid two-phase flow in reactor via Eulerian-Eulerian two-fluid model. The computational fluid dynamic(CFD) simulation is used to analyze the gas-solid flow characteristics of three zones in the riser reactor of MIP process, i.e., the pre-lifting zone, the first reaction zone, and the second reaction zone, which was made via the velocity distribution at different elevations,respectively. Moreover, the comparison with the flow characteristics inside the reactor is also made according to different ratios of catalyst to feed oil, i.e., 6, 7 and 8, respectively. It is shown from the simulation results that there exist typical non-uniform flow characteristics inside the riser reactor of MIP process. The flow in the pre-lifting zone shows a typical ring-core distribution. The maximum axial velocity of catalyst occurs in the region of about one quarter and three quarters of the radius in the first reaction. The second reaction zone has the same distribution characteristics as the first one, but the velocity of the second reaction zone is lower than that of the first one. As the ratio of catalyst to feed oil increases, both the axial velocity of the catalyst particles and the solid phase volume fraction increase.