表面更新釜中粘弹性流体的脱挥特性测定

Devolatilization of Viscoelastic Fluids in a Surface-Renewal Apparatus

出于消化引进及自行开发聚合物系脱挥设备的需要,对粘弹性流体在双轴表面更新釜中装带刮刀的眼镜型桨及圆盘桨时脱挥性能进行了实验研究。用氧探头技术测定液侧容积传质系数k_La。结果表明,在扩散脱挥区域,粘弹性对容积传质系数无明显影响;装料量对k_La有显著的影响;带刮刀的眼镜型桨的脱挥性能优于圆盘桨。将实验结果在广泛的条件下进行了关联。

This article reports the study on devolatilization of viscoelastic fluids in a surface-renewal vessel with two axes, which is usually adopted in polyester and polystyrene manufacture processes. The experiments are carried out under a variety of conditions on kL a such as the impeller types, the number of impellers equipped with, feed volume and viscoelasticity etc. Liquid-phase volumatric mass transfer coefficients kLa in PAA-O2 systems is determined by oxygen probe technique. The results show that kL a is almost independent of the viscoelasticity of fluids and the spectacles-shaped impeller in devolatilization characteristics is superior to disc-shaped one. A correlative equation is obtained as follows:Sh = A0 (l/Di) A1(1- (VL /V* ) 2) A2 (NDi2/DL ) A2