Ethylene glycol composition, preparation method thereof, and polyester prepared from the ethylene glycol composition

A method for preparing an ethylene glycol composition, comprising steps of:

• (1) reacting CO with methanol to generate dimethyl oxalate, hydrogenating the dimethyl oxalate to generate ethylene glycol, and passing the ethylene glycol through a methanol recovery tower and a dehydration tower to obtain a crude ethylene glycol;
• (2) feeding the crude ethylene glycol to a light fraction removal tower, feeding a heavy fraction of the light fraction removal tower to an ethylene glycol product tower, and distilling the heavy fraction of the light fraction removal tower in the ethylene glycol product tower to obtain an ethylene glycol product;
• (3) feeding a light fraction of the light fraction removal tower to a specific alcohol recovery tower, distilling the light fraction of the light fraction removal tower in the specific alcohol recovery tower, and obtaining an ethylene glycol solution containing a high concentration of a specific alcohol from a bottom of the specific alcohol recovery tower;
• and
• (4) mixing the ethylene glycol solution containing the high concentration of the specific alcohol obtained in the step (3) with the ethylene glycol product obtained in the step (2) in appropriate amounts according to a desired concentration of the ethylene glycol composition.