减压精馏—闪蒸分离混合苯二甲酸增塑剂

Seperation of DOIP & DOTP from Mixed Ester Via Vacuum-flash Distillation

PTA生产过程中会产生大量的TA残渣,该残渣中含有大量的苯甲酸、钴锰盐、苯二甲酸等有机物,本文通过减压精馏、闪蒸,对混合苯二甲酸增塑剂进行了进一步的分离,获得了最佳分离条件:塔顶压强在0.2 kPa左右,苯甲酸辛酯采出时塔顶气相温度控制在115℃左右,回流比控制在6∶1,精馏工段最终气相温度控制在190℃,通过进一步闪蒸可以得到纯度很高的三酯混合物。其中苯甲酸辛酯产出率为8.79%,三酯混合物产出率为75.7%,全工段产品、副产品总收率为99.46%。实际生产中可以通过工艺的系统化进一步提高产品的纯度和收率,该方法得到了附加值更高的产品,为TA残渣的高效利用提供了一个指导。

The TA residue which produced from PTA cobalt manganese salt, terephthalic acid and other production contains large amounts of benzoic acid, organic matter. After further separation of mixed phthalate plasticizers to obtain the best separation conditions by vacuum -flash distillation：top pressure of the tower is about 0.2 kPa, the system is stable running for 5 - 6 h of benzene formic acid octyl, its tower gas recovery temperature controlled at about 115 ℃ ,the reflux ratio controled at 6 ： 1 ,the distillation sec- tion in the final gas temperature is controlled at about 190 ℃, 14 -15 h after the stop recovery through flash can get high purity ester mixture, the output ratio of benzoic acid octyl is 8.96% ,the output rate of three ester mixture 75.49% ,the total yield of in products,by - product in whole section is 99.37%. Ac- production, through the systematic process to further improve product purity and yield of higher value added products, and provides a guidance for the efficient use of the TA residues.