超声内环流气升式反应器传质性能的研究

研究了超声内环流气升式反应器中空气-水-离子交换树脂体系的气液传质与液固传质性能.分别采用电极动态法和离子交换树脂法实验测定了气液传质和液固传质系数.重点考察了表观气速、超声电功率对于气液传质系数以及液固传质系数的影响.实验表明,内环流气升式反应器中表观气速对于气液传质性能影响较大,而超声作用对气液传质影响不大.该反应器中液固传质系数随表观气速的增加而增大;无超声作用情况下,当表观气速达到一定程度时,液固传质系数保持一恒定值.超声作用时,气速增加到4 cm·s-1左右,传质系数达到最大值,随后液固传质系数随着表观气速的增加而逐渐减小,传质系数仍然大于无超声作用时的值.超声对液固传质有较强的促进作用,电功率在150 W左右时,超声对液固传质的促进作用最佳,是不加超声作用时传质系数的两倍左右;但随着电功率的进一步增大,液固传质系数呈现下降趋势.

Mass Transfer Characteristics in Ultrasonic Internal Airlift Loop Reactor

The gas-liquid mass transfer characteristic and the liquid-solid mass transfer characteristics of air-water-ion exchanger resin system were studied in a 1L ultrasonic internal airlift loop reactor. The volumetric gas-liquid transfer coefficient (KLa) and the liquid-solid mass transfer coefficient (kl,s) were measured experimentally by the dynamic electrode method and the ion exchanger resin method, separately. The results show that the superficial gas velocity (Ugr) has the primary effect on KLa and the ultrasound has only a little influence on it. However for kl,s, both the superficial gas velocity and ultrasound have great effect on it. When no ultrasound is used, the kl,s, increases with increasing superficial gas velocity and then becomes to keep constant after the superficial gas velocity increases to a certain extent. When the ultrasound is used, the kl,s, increases with the ultrasonic electric power at first and then decreases, anyhow, under the same Ugr, all the kl,s with ultrasound are larger than those without ultrasound. The optimal ultrasonic electric power to be used is about 150W, using which, the kl,s reaches its maximum and is almost twice of that without ultrasound. Furthermore, the kl,s with ultrasound increases with the superficial gas velocity at first and reaches its maximum when Ugr is increased to about 4 cm.s-1.