文献类型：专利

英文题名：Separating low concentration 1,2-butanediol from ethylene glycol by azeotropic distillation involves introducing mixture of ethylene glycol and 1,2-butanediol together with dimethyl oxalate into ethylene glycol separation tower

作者：SHEN R;LI W;ZHOU J;ZHENG S;SUN J

机构：[1]UNIV EAST CHINA SCI & TECHNOLOGY

申请号：CN108017517-A

申请日：2017-12-29

公开日：2018-05-11

语种：英文

收录：DERWENT

摘要：NOVELTY - Separation of low concentration 1,2-butanediol from ethylene glycol by azeotropic distillation involves: (1) introducing a mixture of ethylene glycol and 1,2-butanediol together with dimethyl oxalate as azeotropic agent into an ethylene glycol separation tower; (2) introducing a mixture of ethylene glycol and dimethyl oxalate from the bottom of tower into an ethylene glycol refining tower; (3) introducing an azeotropic mixture from the top of tower into a low-pressure azeotropic distillation tower; (4) recycling ethylene glycol product and dimethyl oxalate from the top and bottom of refining tower to the ethylene glycol separation tower; and (5) obtaining 1,2-butanediol from the bottom of low-pressure azeotropic distillation column and an azeotropic mixture from the top of low-pressure azeotropic distillation column, and then introducing the azeotropic mixture in top of low-pressure azeotropic distillation column into a high-pressure azeotropic distillation column. USE - The method is useful for separating low concentration 1,2-butanediol from ethylene glycol by azeotropic distillation. The dimethyl oxalate is useful as azeotropic agent in azeotropic rectification method (claimed). ADVANTAGE - The method enables economical separation of low concentration 1,2-butanediol from ethylene glycol by azeotropic distillation with reduced energy consumption and high purity and yield. DETAILED DESCRIPTION - Separation of low concentration 1,2-butanediol from ethylene glycol by azeotropic distillation involves: (1) introducing a mixture of ethylene glycol and 1,2-butanediol together with dimethyl oxalate as azeotropic agent into an ethylene glycol separation tower; (2) introducing a mixture of ethylene glycol and dimethyl oxalate from the bottom of tower into an ethylene glycol refining tower; (3) introducing an azeotropic mixture from the top of tower into a low-pressure azeotropic distillation tower; (4) recycling ethylene glycol product and dimethyl oxalate from the top and bottom of refining tower to the ethylene glycol separation tower; (5) obtaining 1,2-butanediol from the bottom of low-pressure azeotropic distillation column and an azeotropic mixture from the top of low-pressure azeotropic distillation column, and then introducing the azeotropic mixture in top of low-pressure azeotropic distillation column into a high-pressure azeotropic distillation column; (6) obtaining dimethyl oxalate from the bottom of high-pressure azeotropic distillation column, mixing the material flow with the tower top material flow of ethylene glycol refining tower and then returning to the separation tower for recycling; and (7) circulating the azeotropic mixture from the top of high-pressure azeotropic distillation tower into the low-pressure azeotropic distillation tower. The azeotropic mixture is a mixture of 1,2-butanediol and dimethyl oxalate. The operating pressure of the separation tower is 8-10 bar, the number of tower plates in the separation tower is 60-80, and the reflux ratio of ethylene glycol and 1,2-butanediol together with dimethyl oxalate is 6-10. The operating pressure of ethylene glycol refining tower is 8-10 bar, the number of tower plates in the refining tower is 72-95, and the reflux ratio of ethylene glycol and dimethyl oxalate in the refining tower is 5-12. The operating pressure of low-pressure azeotropic distillation column is 5-10 bar, the number of trays in the distillation column is 60-90, and the reflux ratio of 1,2-butanediol and dimethyl oxalate in the distillation column is 8-20. The operating pressure of the high-pressure azeotropic distillation column is 10-30 bar, the number of trays in the high-pressure azeotropic distillation column is 60-90 and the reflux ratio in the high-pressure azeotropic distillation column is 6-20.