Process for purification of recovered glycol from chemical recycling of waste polyester

A process for purifying polyester-grade ethylene glycol from crude ethylene glycol, comprising:

• (a) providing crude ethylene glycol from a process for the depolymerization of polyethylene terephthalate (PET) to form a terephthalate, comprising:
• (i) admixing the polyethylene terephthalate (PET) with a first solvent that is methanol to yield a first mixture;
• (ii) adding a glycoxide to the first mixture;
• (iii) adding a second solvent that is methanol;
• (iv) admixing;
• and
• (v) evaporating or distilling crude ethylene glycol from the terephthalate;
• (b) introducing the crude ethylene glycol stream into a first distillation column for distilling a first component and removing the first component from the process, wherein a portion of a tail stream from the first distillation column is introduced into a first reboiler to provide heat energy to vaporize a portion of the tail stream for reintroduction into the first distillation column;
• (c) withdrawing a first stream from a bottom of the first distillation column and feeding the first stream into a second distillation column for distilling a second component and removing the second component from the process, wherein a portion of a tail stream from the second distillation column is introduced into a second reboiler to provide heat energy to vaporize a portion of the tail stream for reintroduction into the second distillation column;
• (d) withdrawing a second stream from a bottom of the second distillation column and feeding the second stream into a third distillation column, wherein a portion of a tail stream from the third distillation column is introduced into a third reboiler to provide heat energy to vaporize a portion of the tail stream for reintroduction into the third distillation column;
• and
• (e) recovering polyester-grade ethylene glycol from top of the third distillation column, wherein the purity of the polyester-grade ethylene glycol is at least 99.9%.