Research On The Process Of Removing Voc By High Gravity

In the process of producing polymer,there are some volatile components in the polymer inevitably,so the devolatilization process is particularly important.As a typical process strengthening equipment,rotating packed bed(RPB)can generate high gravity to break the liquid phase into micro size units such as thin film,thin line and droplet in the packing,and can quickly update the surface to strengthen the gas-liquid contact and separation process.The application of RPB in the devolatilization process has the advantages of not easy to stick and block,easy to break bubbles and has fast surface renewal.So it is of great significance to study the devolatilization process of the rotating packed bed.In this paper,the devolatilization performance of RPB with traditional stainless steel wire mesh packing was studied firstly,and then three kinds of integral rotors with different structures were designed,which are circular column,circular column wire mesh and water-drop column wire mesh,and the three rotors were made by 3D printing.The effect of different rotor structures and packings on the devolatilization of RPB was investigated,at the same time,the effect of the cross wire and the shape of the vertical wire on the devolatilization process was explored The results are as follows:(1)When the rotor structure is different,the removal efficiency of volatile E and the total volume mass transfer coefficient of liquid phase KLa have the same trend with the increase of rotating speed,feed volume flow rate,vacuum degree and initial volatile content,that is,with the increase of rotating speed,E and KLa increase,but the increase amplitude is reduced;with the increase of feed flow rate,E decreases,KLa approximately increase linearly with the increase of flow rate;with the increase of the vacuum degree in the RPB,E and KLa increase;with the increase of the initial content of acetone,E and KLa increase.(2)Four kinds of RPB,The traditional stainless steel wire mesh,circular column,circular column wire mesh and water-drop column wire mesh,under the same operating conditions and initial volatile content,the order of E and KLa is:water-drop column wire mesh>traditional stainless steel wire mesh>circular column wire mesh>circular column.The results show that the shape of vertical wire has a great influence on the devolatilization.Under the same operating conditions and initial volatile content,the E and KLa of the water-drop column wire mesh RPB are 2.38%?12.93%and 9.85%?68.99%higher than those of the traditional stainless steel wire mesh RPB respectively,while the E and KLa of the traditional stainless steel wire mesh RPB are 3.90%?15.22%and 22.04%?105.02%higher than those of the circular column wire mesh RPB respectively.Compared with the devolatilization performance of circular column and circular column wire mesh,it can be seen that the existence of cross wire will play a great role in mass transfer,under the same initial volatile content and operation conditions,the E and KLa of circular column wire mesh RPB are 1.15%?10.99%and 6.06%?284.21%higher than those of circular column RPB,respectively.