Process for refining a crude ethylene glycol stream

A process for refining a crude ethylene glycol stream comprising monoethylene glycol and at least one acid contaminant is disclosed. The process comprises reacting the acid contaminant with the monoethylene glycol in at least one reaction zone to form an ester and removing the ester by separation. Preferably a catalyst selected from silica, resin (such as PTFE resin or a sulfonated divinyl styrene benzene polymeric), zeolites and silica-alumina is used. The acid contaminant may be methoxyacetic acid or glycolic acid. The crude ethylene glycol stream may be produced by hydrogenation of methyl glycolate, in turn produced by esterification of glycolic acid with methanol. In one embodiment, in a purification system crude ethylene glycol stream 20 comprising monoethylene glycol (MEG), methoxyacetic acid and glycolic acid, and possibly diethylene glycol, is fed to esterification reactor 26 in which the acid contaminants are esterified by reaction with the MEG with a resin catalyst at 60-80°C. Outlet stream 32 from reactor 26 is fed to distillation column 28 where water and other light components are removed in overhead stream 29. Bottom stream 30 may be fed to a further esterification reactor 31 in which remaining acid contaminants are esterified.