结晶釜直径对SAS成粒过程影响的CFD研究  

CFD analysis of precipitator's diameter effects on supercritical antisolvent micronization(SAS)

作　　者：张敏华[1] 王召亚 李永辉[1] 耿中峰[1] 

机构地区：[1]天津大学,天津大学石油化工技术开发中心,绿色合成与转化教育部重点实验室,天津300072

出　　处：《计算机与应用化学》2013年第7期703-708,共6页Computers and Applied Chemistry

摘　　要：为探讨结晶釜直径对SAS(超临界抗溶剂法)过程的影响规律,并确定适宜的结晶釜直径,本文采用计算流体力学(CFD)方法,选用Realizableκ-ε湍动模型对SAS喷射过程建立模型。结晶釜高度为L=190 mm,考察了直径分别为40 mm、30 mm、20 rnm和15 mm时釜内流体迹线、溶剂浓度分布、有效扩散因子分布及湍动强度分布变化规律,尤其是喷嘴出口附近溶液射流区内的流场变化状况。结果表明,随着结晶釜直径的减小,釜内漩涡区逐渐向釜顶缩小,有利于避免釜内颗粒间碰撞造成的粘结;釜内溶剂浓度逐渐减小,而有效扩散因子分布及湍动强度的绝对值逐渐增大但分布范围逐渐向釜顶缩小:喷嘴出口附近溶液射流区内的有效扩散因子与湍动强度逐渐增大,有利于提高成核速率而减小颗粒粒径。较小直径的结晶釜,还会降低流体在釜内的停留时间,减少颗粒生长时间而利于减小颗粒粒径,因此选择小直径结晶釜对SAS过程有利。本文通过CFD模拟研究,揭示了SAS结晶釜直径对SAS成粒过程的影响规律,对SAS结晶釜的优化设计具有一定的理论指导。A Computer fluid dynamic （CFD） model was established using the Realizable κ-ε turbulent model herein in order to investigate the precipitator＇s diameter effects on the particle sizes and morphology in the Supercritical antisolvent （SAS） process and determine the optimum diameter of the precipitator. The CFD model was used to study the influence of the SAS precipitators diameter of 40 mm, 30 mm, 20 mm and 15 mm on the fluid pathline, DMSO mole fraction distribution, Dey distribution, and turbulent intensity distribution. These influences near the nozzle were studied especially. It can be concluded that the swirl shrinked towards the top of the precipitator, which helped avoid agglutinating among the particles due to the collision; the concentration of the solvent reduced, and the De~ and I increased but with less scope when the precipitator diameter decreased; the De~ and I increased in the solution jet near the nozzle exit, which was benefited to reduce the particle size as it helped to speed up the nucleation rate. In addition, precipitators with smaller diameter shortened the residual time of the fluid, and therefore reduced the particle growth time resulting in obtaining smaller particles. The CFD results explained the precipitator＇s diameter effects on the SAS process. This paper remarkably provided insight into the mechanisms that govern the particle sizes in the SAS process.

关 键 词：SAS(超临界抗溶剂法) 结晶釜 直径 CFD 喷嘴 

分 类 号：TQ015.9[化学工程] TP391.9[自动化与计算机技术—计算机应用技术]