新型聚醚酮熔体过滤装置的设计与应用

Design and Application of New Type of Melt PEK Filter

聚醚酮合成反应时产生细小胶体杂质,原料、精制及干燥过程会带入诸如灰尘等杂质,另外熔体挤出造粒中,聚醚酮因长时间塑化和加热产生碳化。这些杂质进入挤出模具中,会造成流道堵塞或制品残缺,不同程度地影响聚醚酮的应用范围。采用挤出机熔融、加压,经熔体泵加压,再经过高目数过滤网,成功实现了聚醚酮熔体的连续过滤。由于产量扩大,原有过滤设备已满足不了生产需要。经过放大原有设备,生产运行表明:由于网片区域空间过大,难控制网片表面的温度。温度过高会使物料出现变性;网片面积大易变形,杂质逃逸,不能实现聚醚酮预定过滤目标。根据已成功实现过滤的经验,设计一种新型过滤装置,采用双柱,每柱双网。过滤条件为:加料速度175 kg/h;挤出机加热温度375℃;出口压力12 MPa;熔体泵出口压力22～40 MPa;过滤网304材质;网块直径200 mm、网区直径180 mm、网孔最小直径5μm;换网次数1次/55分针。测试结果为过滤后杂质粒径小于5μm,纯物料收率91.4%。

PEK synthesis reaction could produce fine solid impurities, raw materials, refining. Drying process could also bring into such as dust and other impurities, In melt extrusion,PEK could generate residue by long time heating plasticizing, and impurities would cause the clogging of the flow path or products of incomplete. It affected PEK application scope in different degree. According to the filtering requirements, it made extruder, screen changer, melt pump, filter for selection and process design to obtain high purity PEK product. Through the equipment structural adjustment,a new type of filtration device was designed,which had double column, dual-network per column, and successfully realized PEK melt filtration. The suitable operation conditions and results as follows：the feeding speed was 40 kg/h,extruder heating temperature was 375 ℃ ,the outlet pressure was 12 MPa,melt pump outlet pressure was 22 - 45 MPa, filter material was 304,diameter of net block was 200 mm, and diameter of net was 180 mm,net mesh diameter was 5 μm,changing the net number was 1 times/55 min. The test results showed that, after filtering with 5 μm,and the pure material yield was 91.4 %.