Ethylene purification

Claim 1

A PROCESS FOR RECOVERING HIGH PURITY ETHYLENE FROM A NORMALLY GASEOUS MIXTURE THEREOF WHICH INCLUDES AS IMPURITIES METHANE, ACETYLENE AND HEAVIER HYDROCARBONS: WHICH COMPRISES PASSING SAID MIXTURE IN COUNTERCURRENT RELATION TO RFRIGERTED REFLUX IN A REBOILED FRACTIONATION ZONE UNDER SUPERATMOSPHERIC PRESSURE AND AT A TEMPERATURE WHEREBY SUBSTANTIALLY ALL OF SAID HEAVIER HYDROCARBONS ARE SEPARATED AS A LIQUID BOTTOMS; WITHDRAWING AN ETHYLENE ENRICHED GASEOUS OVERHEAD MIXTURE INCLUDING METHANE AND ACETYLENE FROM SAID FRACTIONATION ZONE AND COMPRESSING SAID ETHYLENE ENRICHED MIXTURE TO A SUBSTANTIALLY HIGHER PRESSURE THAN THE PRESSURE IN SAID FRACTIONATION ZONE; COOLING SAID COMPRESSED MIXTURE TO FORM AN ETHYLENE ENRICHED CONDENSATE, A PORTION OF SAID CONDENSATE COMPRISING THE REFRIGERATED REFLUX FOR SAID FRACTIONATION ZONE; INTRODUCING THE NET PORTION OF SAID CONDENSATE, AFTER SATISFYING SAID REFLUX REQUIREMENTS, INTO A FLASH ZONE; REDUCING THE PRESSURE ON SAID NET PORTION OF CONDENSATE IN SAID FLASH ZONE TO FORM AN ETHYLENE ENRICHED GASEOUS MIXTURE INCLUDING METHANE AND ACETYLENE AND PASSING SAID GASEOUS MIXTURE THROUGH AN ACETYLENE ABSORPTION ZONE IN COUNTERCURRENT RELATION TO A SELECTIVE SOLVENT OF SUFFICIENT AMOUNT TO ABSORB SUBSTANTIALLY ALL OF THE ACETYLENE IN SAID GASEOUS MIXTURE; AND WITHDRAWING SUBSTANTIALLY PURE ETHYLEN AS AN OVERHEAD GAS FROM SAID ABSORPTION ZONE, A PART OF SAID NET PORTION OF CONDENSATE BEING HEATED PRIOR TO INTRODUCTION INTO SAID FLASH ZONE BY INDIRECTLY EXCHANGING HEAT BETWEEN SAID SUBSTANTIALLY PURE GASEOUS ETHYLENE OVERHEAD AND SAID PART OF SAID NET PORTION OF CONDENSATE.