聚醚酮熔体过滤装置的建立与改进研究

针对聚醚酮的合成反应会产生细小固体杂质,原料、精制及干燥过程会带入灰尘等杂质,熔体挤出造粒时聚醚酮因长时间塑化和加热会产生残渣等问题,设计、建立了聚醚酮连续过滤生产装置,采用挤出机熔融、加压,再经熔体泵加压,经过高目数过滤网对其进行过滤。对装置试运行后出现的问题进行了改进,确定了适宜的操作条件,加料速度40 kg/h,挤出机加热温度375℃;出口压力12 MPa,熔体泵出口压力22～45 MPa,过滤网304材质,网块直径200 mm、网直径180 mm,网孔直径5μm,换网次数1次/h。测试结果表明,过滤后Ф5μm的颗粒杂质个数<6个/cm2,纯物料收率90.5%。

Esteblishment and improvement of melt filter for PEK unit

PEK synthesis reaction is prone to produce fine solid impurities,such as the dust and other impurities the raw materials,refining and drying process bring into,and the residue generated by PEK after long time plasticizing and heating during melt extrusion granulation.If these impurities go into the extrusion die,the clogging of the flow path or product quality issues will occur.To obtain high purity of PEK,a continuous filtering process for PEK was established,that was,the raw materials were melt and exerted pressure by the extruder,then exerted pressure again by melt pump,finally filterd by high mesh filter.According to the filtering requirements,it makes extruder,screen changer,melt pump,filter for selection and process design.Based on the problems occurred during the installation and debugging of the equipment,such as signal distortion,system instability,and so on,the scattered temperature and pressure control systems were use to improve the computer centralized control system.The optimal operation conditions for PEK melt filtration are shown as follows:40 kg/h of feeding speed rate,375℃ of heating temperature for extruder,12 MPa of the outlet pressure,22-45 MPa of melt pump outlet pressure,filter mesh with Ф200 mm,screen with Ф180 mm,screen holes with Ф5 μm and once per hour of the number of changing the screen.The test results show that,after filtering,the number of particles with Ф5 μm is < 6/cm2 and the yield of pure material is 90.5%.