Abstract: The present invention concerns a process for making polyester containing up to 50 percent by weight transparent recycled waste polyester by a novel equilibrium depolymerization process. The equilibrium depolymerization process of the present invention for making polyester containing transparent waste polyester comprises the steps of providing a stream containing oligomers, feeding transparent polyester waste to an extruder, melting in said extruder said waste polyester, extruding said molten polyester into said stream containing oligomers, completing the esterification creating a prepolymer mixture, and polymerizing said prepolymer mixture thereby producing polyester containing waste transparent polyester suitable for food grade applications. The present invention meets or exceeds the Food and Drug Administration (FDA) requirements for food contact with polyester and is thus useful in food contact applications, for example beverage containers and polyester film wrap.

Abstract: A method and apparatus for quenching and scrubbing a hot gas using a liquid in a single packed column while controlling mist formation. Hot gas is introduced at the bottom of the column and drawn upward countercurrent to the scrubbing liquid. The column has three stages, each packed and fed liquid from above. The first stage is a quench region wherein the gas flow rate, liquid flow rate and liquid temperature are controlled such that the quench rate does not exceed 5.4° C./ft2 of packing to prevent formation of an aerosol mist. The second and third stages for scrubbing employ packed regions separately supplied with increasingly cooler and purer liquid.