针对高黏聚合物体系脱挥过程的特点,指出聚合物脱挥技术推广的关键是开发高速表面更新的新型高效传质设备。工业上常规的脱挥设备存在不同的使用限制,本文提出了设计新型旋转填充床用于高黏聚合物脱挥的可能性,并类比螺杆挤出机结构介绍其脱挥机理。结果表明,相比常规的脱挥设备,旋转填充床脱挥效率高,能耗低。采用该技术对丙烯腈系聚合物进行两次循环脱挥处理,丙烯腈脱除率达到99%以上。在脱挥过程中,解吸的挥发分气体在第一时间离开填料层,并迅速由真空泵抽走,防止了挥发分的二次溶解。
A crucial issue for the popularization of high viscous polymer devolatilization process is to develop high efficiency mass transfer apparatus with improved surface renewal rate. For the limitations of conventional apparatuses,a vertical rotating packed bed for high viscous polymer devolatilization process is proposed. The devolatilization mechanism of the proposed apparatus is illustrated by analogizing with the structure of screw extruder. Results show that the rotating packed bed has a higher devolatilization efficiency and a lower energy consumption as compared with conventional devices. Using the proposed vertical rotating packed bed,the acrylonitrile monomer removal efficiency from polyacrylonitrile can be achieved to over 99% upon twice devolatilized. As the desorbed volatiles can depart as soon from the packed bed and then be transfered by vacuum bump,this proposed technology will efficiently prevent the secondary dissolution of the volatiles.