A process for recycling of polyethylene terephthalate (pet) waste

A process for recycling of polyethylene terephthalate (PET) from polyethylene terephthalate (PET) waste, said process comprising the steps of:

• partially depolymerizing the polyethylene terephthalate (PET) waste by mixing the polyethylene terephthalate (PET) waste with ethylene glycol in a weight ratio of PET:ethylene glycol ranging from 1:0.3 to 1:1.5 while maintaining a temperature of the mixture in a range of 200° C. to 250° C. to obtain a partially depolymerized polyethylene terephthalate (PET);
• depolymerizing the partially depolymerized polyethylene terephthalate (PET) by contacting the partially depolymerized polyethylene terephthalate (PET) with ethylene glycol in a weight ratio of PET:ethylene glycol ranging from 1:1 to 1:4 in the presence of a depolymerization catalyst at a temperature ranging from 170° C. to 200° C. for a time period ranging from 2 hours to 5 hours to produce a crude product mixture comprising bis(2-hydroxyethyl) terephthalate (BHET);
• purifying the crude product mixture to obtain purified bis(2-hydroxy ethyl) terephthalate (BHET);
• and
• depolymerizing the purified bis(2-hydroxyethyl) terephthalate (BHET) in h presence of a polymerization catalyst at a temperature ranging from 200° C. to 300° C. and at a pressure ranging from 50 mbar to 2 mbar for a time period ranging from 2 hours to 5 hours to obtain the recycled polyethylene terephthalate (PET).

A system for production of bis(2-hydroxyethyl) terephthalate (BHET) from polyethylene terephthalate (PET), comprising:

• a first reaction vessel;
• at least one first conduit configured to feed polyethylene terephthalate (PET) and ethylene glycol into the first reaction vessel, wherein polyethylene terephthalate (PET) and the ethylene glycol are in a weight ratio of PET:ethylene glycol ranging from 1:0.3 to 1:1.5 and maintained at a temperature in a range of 200° C. to 250°, resulting in partially depolymerized polyethylene terephthalate (PET);
• and
• a second reaction vessel;
• a depolymerization catalyst in the second reaction vessel;
• and
• at least one second conduit configured to feed the partially depolymerized polyethylene terephthalate (PET) and ethylene glycol into the second reaction vessel, wherein the partially depolymerized polyethylene terephthalate (PET) and the ethylene glycol are in a weight ratio of PET:ethylene glycol ranging from 1:1 to 1:4 maintained at a temperature ranging from 170° C. to 200° C. for a time period ranging from 2 hours to 5 hours, resulting in a crude product mixture comprising bis(2-hydroxyethyl) terephthalate (BHET),
• wherein the first reaction vessel may be the same or different from the second reaction vessel;
• wherein the at least one first conduit may be the same or different from the second conduit;
• and
• wherein the depolymerization catalyst is not present in the first reaction vessel when the polyethylene terephthalate (PET) and ethylene glycol are fed into the first reaction vessel.