双轴搅拌对晶粒降温结晶的影响  

Influence of Coaxial Mixer on Cooling Crystallization

作　　者：王博 张钰波 刘宝庆[1] WANG Bo;ZHANG Yubo;LIU Baoqing(Intiute of Proces Equipment,Zhejiang University,Hangzhou 310027,China)

机构地区：[1]浙江大学化工机械研究所,浙江杭州310027

出　　处：《轻工机械》2023年第2期1-9,共9页Light Industry Machinery

基　　金：国家自然科学基金(21978255)。

摘　　要：工业结晶过程中,一般希望结晶产物具有均匀的粒度和规则的晶形。考虑到带有外桨的双轴搅拌器能有效促进结晶过程的传质与传热,因此课题组以双轴搅拌器作为研究对象,通过实验考察了转速、桨型以及内外桨搅拌模式等参数对结晶产物粒度分布及晶型晶貌的影响;根据不同转速下测得的晶体成核生长动力学参数,建立氯化钾结晶成核速率与生长速率的预测公式。结果表明:双轴搅拌得到的晶体中值粒径明显高于单轴搅拌,但由于外桨的存在,使得粒度分布离散度变大;存在一个最佳转速使晶体中值粒径达到最大且粒度分布较为集中;内外桨同转、桨叶选用轴流桨或混流桨时更适用于结晶操作。氯化钾结晶成核速率与生长速率的预测公式为工业结晶提供一定的理论参考。In the process of industial cystallization,it is generally expected that the crystal products have uniform particle size and regular crystal shape.Considering the coaxial mixer with outer blade can effectively promote mass and heat transfer in the eystallization process,the effects of parametens such as rotation speed,agitator blade type and stiming mode of inner and outer blade on crystal size distribution and crystal morphology of crystallization products by taking the coaxial mixer as the research object.In addition,the predictive fomula of nucleation and growth rate of potassium chloride was established according to the kinetie parametens of crystal nucleation growh measured at different rotational speed.The results show that the median crystal size obtained by coaxial mixer is significantly higher than that of uniaxial stiming,but the dispersion of crystal distribution increases due to the presence of outer blade;there is an optimal rotation speed to maximize the crystal size and make the crystal size distribution more concentrated;it is more suitable for erystallization operation when the inner and outer blades are rotating in the same direction with the axial flow or mixed flow blades.The predictive formula of nucleaton and growth rate of potassium chloride can provide certain theoretical reference for industrial crystallization.

关 键 词：双轴搅拌 降温结晶 晶体形貌 粒度分布 

分 类 号：TQ027.2[化学工程] TH74[机械工程—光学工程]