Demethanization of cracked gases

Claim 1

A METHOD FOR DEMETHANIZING A GAS COMPRISING METHANE, ETHYLENE, ETHANE, PROPYLENE AND HYDROGEN COMPRISING CHILLING SAID GAS IN SUCCESSIVE CHILLING STAGES TO A TEMPERATURE OF ABOUT -120* F. AT A FINAL PRESSURE OF ABOUT 870 P.S.I.A., SEPARATING A SEPARATE LIQUID CONDENSATE FROM EACH OF THE SUCCESSIVE CHILLING STEPS FROM UNCONDENSED GAS, EXPANDING SAID UNCONDENSED GAS TO A TEMPERATURE OF ABOUT -220* F. AND AT ABOUT 45 P.S.I.G. TO PRODUCE ADDITIONAL CONDENSATE, SEPARATING THE EXPANDED PRODUCT INTO A GAS PHASE AND A LIQUID PHASE, INTRODUCING THE SEPARATE CONDENSATES AT SUCCESSIVE LEVELS IN A FRACTIONAL DISTILLATION ZONE, THE CONDENSATE PRODUCED BY THE LAST AND LOWEST TEMPERATURE CHILLING STAGE OF SAID SUCCESSIVE CHILLING STAGES BEING INTRODUCED INTO SAID FRACTIONALD DISTILLATION ZONE AT THE HIGHEST LEVEL OF SAID SUCCESSIVE LEVELS, INTRODUCING THE CONDENSATE PRODUCED IN THE EXPANDING OPERATION INTO SAID FRACTIONATION ZONE AT A STILL HIGHER LEVEL THAN THE HIGHEST LEVEL OF SAID SUCCESSIVE LEVLS, FRACTIONATING THE SO-INTRODUCED CONDENSATES AT A PRESSURE OF ABOUT 400 P.S.I.G. AND WITH REFLUX AT A TEMPERATURE OF ABOUT -120* F. TO PRODUCE AN OVERHEAD PRODUCT RICH IN METHANE AND KETTLE PRODUCT RICH IN ETHANE AND THYLENE.

Claim 2

A METHOD FOR DEMETHANIZING A GAS COMPRISING METHANE, ETHYLENE, ETHANE, PROPYLENE AND HYDROGEN COMPRISING CHILLING SAID GAS IN SUCCESSIVE CHILLING STAGES TO A TEMPERATURE OF ABOUT -120* F. AT A FINAL PRESSURE OF ABOUT 870 P.S.I.A., SEPARATING A SEPARATE LIQUID CONDENSATE FROM EACH OF THE SUCCESSIVE CHILLING STEPS FROM UNCONDENSED GAS, EXPANDING SAID UNCONDENSED GAS TO A TEMPERATURE OF ABOUT -220* F. AND AT ABOUT 45 P.S.I.G. TO PRODUCE ADDITIONAL CONDENSATE, SEPARATING THE EXPANDED PRODUCT INTO A GAS PHASE AND A LIQUID PHASE, INTRODUCING THE SEPARATE CONDENSATES AT SUCCESSIVE LEVELS IN A FRACTIONAL DISTILLATION ZONE, THE CONDENSATE PRODUCED BY THE LAST AND LOWEST TEMPERATURE CHILLING STAGE OF SAID SUCCESSIVE CHILLING STAGES BEING INTRODUCED INTO SAID FRACTIONALD DISTILLATION ZONE AT THE HIGHEST LEVEL OF SAID SUCCESSIVE LEVELS, INTRODUCING THE CONDENSATE PRODUCED IN THE EXPANDING OPERATION INTO SAID FRACTIONATION ZONE AT A STILL HIGHER LEVEL THAN THE HIGHEST LEVEL OF SAID SUCCESSIVE LEVLS, FRACTIONATING THE SO-INTRODUCED CONDENSATES AT A PRESSURE OF ABOUT 400 P.S.I.G. AND WITH REFLUX AT A TEMPERATURE OF ABOUT -120* F. TO PRODUCE AN OVERHEAD PRODUCT RICH IN METHANE AND KETTLE PRODUCT RICH IN ETHANE AND THYLENE.