Abstract: A mobile process to reclaim spent aqueous glycol solutions used as heat transfer fluids and which contains deleterious contaminants, oil/grease, corrosion products, and additives such as buffers and corrosion inhibitors. Particulate contaminates and oil/grease are removed by passing the solution through an ultrafiltration membrane. The dissolved contaminants are removed by passing through a series of ion exchange resin (IER) vessels. The reclaimed glycol solution is reused after replacing the required additives. One embodiment provides for central processing of the filtration and absorption media housed in a mobile enclosure, such as a trailer. The mobile trailer may be used at various collection sites for cleaning and reprocessing spent glycols. After the media are spent, the mobile trailer is returned to a central processing facility for regeneration of the filtration and absorption media. The waste produced by the regeneration is concentrated at a single treatment and disposal facility.

Abstract: The present invention is an improved process for the recovery of ethylene glycol from spent glycol generated in the manufacture of polyethylene terephthalate. The spent glycol typically consists of metal oxide catalyst residues, low molecular weight terephthalate oligomers, diethylene glycol and other trace impurities. The improved process of the present invention is based on the principle that elevating the temperature of the spent glycol increases the solubility of the low molecular weight oligomers so that the low molecular weight oligomers can be dissolved in the ethylene glycol and further that the spent glycol at an elevated temperature may be passed through an ion exchange bed to remove metal oxide catalysts, color forming impurities and other trace impurities.