PTA装置氧化单元过滤系统技术改造

Technological reformation of filtration system for oxidation unit of PTA plant

以采用Dupont工艺技术的600 kt/a精对苯二甲酸（PTA）生产装置为例,介绍了装置氧化单元的过滤工艺及旋转真空过滤机的工作原理;由于旋转真空过滤机存在配套设备较多、能耗偏高、投资偏高等问题,需对其过滤系统进行改进;以旋转液压过滤机取代旋转真空（压力）过滤机,对旋转液压过滤机的技术特点进行了分析,将其应用于生产。结果表明：旋转液压过滤机的基本操作参数设定为压力0.50～0.60 MPa,温度142～148℃,过滤压差0.22～0.26 MPa,转速1 r/min,在此条件下得到了操作停留时间为洗涤时间10 s,脱水时间10 s,反吹时间10 s,其旋转液压过滤机处理效果较好;在停留时间相同、负荷相同的条件下,旋转液压过滤机的处理能力是旋转真空（压力）过滤机处理能力的2倍左右,其能耗和投资分别是旋转真空（压力）过滤机的30%,35%。

The filtration process of oxidation unit and the working principle of rotary vacuum filter were introduced by using a 600 kt/a purified terephthalic acid （PTA） plant of Dupont process as an example. The filtration system was reformed because of complex auxiliary equipments, high energy consumption and high investment. The rotary vacuum （pressure） filter was replaced with a rotary hydraulic filter. And the technological characteristics of the rotary hydraulic filter was analyzed and the production application was carried out. The results showed that the basic operation parameters of rotary hydraulic filter were set as pressure 0.50 -0.60 MPa, temperature 142 - 148 ℃, filtration pressure difference 0.22 -0.26 MPa, rotation speed 1 r/min; the filtra- tion effect was satisfying when the residence time was decided as washing time 10 s, dewatering time 10 s and blowback time 10 s based on the basic operation parameters; the rotary hydraulic filter was about twice the filtration efficiency of rotary vacuum （pressure） filter and was 30% and 35% of the rotary vacuum （pressure） filter in the energy consumption and investment cost, respectively, at the same residence time and load.