Patent ID: 7235677
Filing Date: 2007-06-26
Classification: C07D,Y02P

Abstract:
1. A method of improving the operation of an existing ethylene oxide manufacturing process, said method comprises: a.) operating an epoxidation reactor system by: charging a first reactor feed, having a first carbon dioxide concentration, to said epoxidation reactor system comprising an epoxidation reactor containing a first volume of high activity epoxidation catalyst; yielding from said epoxidation reactor system a first epoxidation reactor effluent; charging at least a portion of said first epoxidation reactor effluent to an ethylene oxide absorber used for separating said first epoxidation reactor effluent into a first recycle stream, having a second carbon dioxide concentration, and a first ethylene oxide stream; dividing said first recycle stream into a first split portion and a first remaining portion; providing a carbon dioxide removal system which includes a carbon dioxide absorber and a solvent regenerator, wherein said carbon dioxide absorber provides for receiving a carbon dioxide-containing feed gas and for contacting said carbon dioxide-containing feed gas with a lean solvent to yield a rich solvent and a carbon dioxide depleted gas stream, and wherein said solvent regenerator provides for receiving said rich solvent and separating carbon dioxide therefrom and yielding said lean solvent and a carbon dioxide gas stream; charging at least a portion of said first remaining portion to said carbon dioxide removal system as said carbon dioxide-containing feed gas to yield as said carbon dioxide depleted gas stream a second recycle stream, having a third carbon dioxide concentration, and to yield as said carbon dioxide gas stream a first carbon dioxide vent stream; combining at least a portion of said first split portion and at least a portion of said second recycle stream with oxygen and ethylene to thereby form said first reactor feed; b.) replacing at least a portion of said first volume of high activity epoxidation catalyst by: removing from said epoxidation reactor at least a portion of said first volume of high activity epoxidation catalyst and replacing therewith a replacement charge of a second volume of a high selectivity epoxidation catalyst to provide a modified epoxidation reactor system; c.) operating said modified epoxidation reactor system by: charging a second reactor feed, having a fourth carbon dioxide concentration which is lower than said first carbon dioxide concentration, to said modified epoxidation reactor system having said replacement charge; yielding from said modified epoxidation reactor system a second epoxidation reactor effluent; charging at least a portion of said second epoxidation reactor effluent to said ethylene oxide absorber used for separating said second epoxidation reactor effluent into a third recycle stream, having a fifth carbon dioxide concentration, and a second ethylene oxide stream; dividing said third recycle stream into a second split portion, if any, and a second remaining portion; charging at least a portion of said second remaining portion to said carbon dioxide removal system as said carbon dioxide-containing feed gas to yield as said carbon dioxide depleted gas stream a fourth recycle stream, having a sixth carbon dioxide concentration, and to yield as said carbon dioxide gas stream a second carbon dioxide vent stream; and combining at least a portion of said second split portion, if any, and at least a portion of said fourth recycle stream with oxygen and ethylene to thereby form said second reactor feed.