Method for cooling post reactor polyethylene terephthalate flakes

摘要

A process for more rapidly cooling post solid-stating reactor PET flakes is described. The process involves conveying PET flakes from a solid-stating reactor 12 to a first separator 24 in the presence of air and water at an elevated pressure through transfer pipe 16. During transfer through pipe 16 the PET flakes are partially cooled while the water is converted to steam. At separator 24 the PET flakes are separated from the steam before being transferred through pipe 26 in the presence of pressurized air. At the second separator 32 the hot air and any residual water vapour are separated from the now relatively cool PET flakes. The process does not cause any significant change in the molecular weight of the PET flakes.