基于CFD考察新型连续结晶罐的性能

Study on performance of new continuous crystallizer based on CFD simulation

运用计算流体力学(CFD)数值模拟的方法,研究了结晶罐不同功能区(混合区、结晶区)对谷氨酸结晶的影响。考察混合区和结晶区在不同搅拌转速、不同晶体粒径下,结晶罐内晶体颗粒悬浮均匀程度、溢流液与进料液量比例的变化情况。模拟结果表明:结晶罐内2个对搅拌强度不同要求的区间——混合区和结晶区在结晶过程发挥着不同的功能,混合区搅拌桨可以有效调节溢流液量与进料液比例,降低进料液晶体的过饱和度;结晶区搅拌桨对于调节整个罐体晶体的悬浮起主要作用。通过调节结晶罐内各区间搅拌桨转速,控制结晶液溢流量与进料量比例保持为15以上、罐体晶体颗粒浓度标准差在0.2以下时,可以较好满足谷氨酸连续结晶工艺的要求,保证晶体处于较好的结晶环境。

A computational fluid dynamics （CFD） numerical simulation method was used to investigate the influence of different functional areas of new crystallizer （ mixing zone, crystallization zone） on the crystallization process overflow of glutamate. To evaluate the uniformity of suspended solid particles and the change of the ratio of the liquid and the feed liquid, the different stirring speeds crystallization zone were investigated and different crystal sizes of the mixing zone and the . The results show that the mixing zone and the crystallization zone, which have different demands for stirring intensity, play different roles in the crystallization process. The impeller of the mixing zone can effectively adjust the ratio of overflow liquid and feed liquid, and reduce the supersaturation of the feed liquid crystal ; the impeller of the crystalline zone plays a main role in adjusting the suspension of the crystal in the whole tank. By adjusting the speed of impellers in each zone, the ratio of overflow liquid to feed hquid is above 15, and the tank crystal particles uniformity suspended is below 0.2. In that case, it is suitable for the continuouscrystallized glutamate and the preserve of crystal.