组合桨聚合釜内非牛顿流体的混合特性

Mixing performance of agitators in a polymerization reactor with non -Ne wtonian fluid

在476mm的椭圆底有机玻璃聚合釜中,以羧甲基纤维素-甘油水溶液(前者质量分数为1.3%)为实验物系,利用酸碱中和法测定了9种不同的搅拌桨直径与聚合釜直径比接近于1的组合搅拌桨沿聚合釜轴向及径向的混合特性。结果表明:内外螺带-锚式组合桨的轴向混合最强,但径向混合较差。框板式搅拌桨的轴向混合较内外螺带-锚式组合桨弱,但比改进偏框式桨强,其径向混合较后者弱。改进偏框桨的7种不同组合方式沿径向的混合良好,多数组合桨沿轴向的混合较前2种组合桨弱,更接近于平推流。

In a cylindrical polymerization re actor of 0.476m diameter with elliptical bottom and no baffle,axial and radial mixing times were measured by using a decolourization method.Nine agitator configuratio ns including helical ribbon -anchor agitator,traditional frame -plate impeller and 7mod-ified asymmetric frame impellers we re used in the experi-ments.A non -Newtonian carboxymeth yl cellulose(CMC)-glycerin water solution was used as e xperimental liquid,the mass fraction of CMC was 1.3%.The results showed that he-lical ribbon -anchor agitator offered the shortest axial mixingtime and the longest radial mixing time among the nine agita-tors.Traditional frame -plate impeller had a medium axial and radial mixing performance.Most com binations of modified asymmetric frame impellers had much shorter radial mixing times and much longer axial mixing times than those of the former two agitators,more similar with the piston flow.