Process for Separation of Syngas-based EG Developed by China Wuhuan Engineering Company

A process for separating ethylene glycol, which is synthesized from syngas, has been developed by the China Wuhuan Engineering Company, Ltd. This process covers the following procedures. The hydrogenate obtained from hydrogenation of dimethyl oxalate is subjected to pretreatment involving the recovery of methanol, dehydration, removal of esters of oxalic acid, rectification and refining to obtain the ethylene glycol product. Dibutyl ketone used as the azeotropic agent is mixed with the raw ethylene glycol obtained after recovery of methanol, dehydration, and removal of oxalic esters to give the EG-rich azeotrope, which is then subjected to condensation and separation to yield an azeotrope-rich liquid phase and an EG-rich liquid phase. The EG-rich liquid phase is further refined to give a premium EG and an on-spec EG.

This process features good reliability in operation, low investment and operating cost, low energy consumption, easiness in separation of target products and good separation effects. In the practice the adoption of this process can achieve a maximum recovery of EG product equating to 96.7%, with the maximum recovery of azeotropic agent reaching 99.99%.