Process for recovery of ethylene

Claim 1

A PROCESS FOR TREATING A GASEOUS MIXTURE CONTAINING ETHYLENE AND LOWER AND HIGHER BOILING NORMALLY GASEOUS COMPONENTS INCLUDING ACETYLENE AND HYDROGEN TO RECOVER ETHYLENE AS A SUBSTANTIALLY PURE FRACTION, WHICH COMPRISES PARTIALLY LIQUIFYING AND COOLING SAID MIXTURE, SUBJECTING SAID PARTIALLY LIQUEFIED MIXTURE TO DEPROPANIZATION TO SEPARATE THE C4 HYDROCARBONS FROM THE MIXTURE AND PRODUCE A DEPROPANIZER OVERHEAD MIXTURE, PARTIALLY LIQUIFYING THE DEPROPANIZER OVERHEAD MIXTURE BY COMPRESSION AND COOLING, SUBJECTING THE RESULTING PARTIALLY LIQUEFIED AND COOLED MIXTURE TO DEMETHANIZATION TO SEPARATE THE HYDROGEN AND METHANE AS A GASEOUS FRACTION FROM ETHYLENE AND OTHER GASEOUS COMPONENTS HAVING A BOILING POINT ABOVE ETHYLENE, COOLING THE HYDROGEN AND METHANE FRACTION SO AS TO SUCCESSIVELY PARTIALLY LIQUIFY THE FRACTION, SEPARATING THE SUCCESSIVELY LIQUIFIED PORTIONS FROM THE UNLIQUIFIED PORTIONS AND RELEASING THE PRESSURE ON THE LIQUIFIED PORTIONS TO ADIABATICALLY EXPAND SAID PORTION TO PROVIDE COOLING FOR THE SUCCESSIVE PARTIAL LIQUIFICATION OF THE METHANEHYDROGEN FRACTION UNTIL A SUBSTANTIAL PROPORTION OF THE METHANE IS LIQUIFIED LEAVING A GASEOUS FRACTION OF PREDOMINANTLY HYDROGEN, CONTACTING THE GASEOUS FRACTION OF PREDOMINANTLY HYDROGEN WITH ETHANE COMING FROM A FOLLOWING STEP IN THE PROCESS TO ABSORB THE MAJOR PORTION OF THE METHANE FROM THE HYDROGEN, CHARGING THE HYDROGEN TO A FOLLOWING HYDROGENATION STEP IN THE PROCESS TO HYDROGENATE THE ACETYLENE, SUBJECTING THE ETHYLENE AND GASEOUS COMPONENTS BOILING ABOVE ETHYLENE OBTAINED FROM