Low temperature purification of ethylene

Claim 1

A METHOD OF SEPARATING ETHYLENE FROM A STREAM CONTAINING IT, ETHANE, AND WATER AS AN IMPURITY WHICH COMPRISES FEEDING SAID STREAM TO A FRACTIONATION COLUMN BEING OPERATED AT A TEMPERATURE AT WHICH HYDRATES OF EHTYLENE WILL FORM, PRODUCING AND REMOVIG FROM SAID COLUMN AN OVERHEAD STREAM CONSISTING ESSENTIALLY OF ETHYLENE, CONTACTING SAID OVERHEAD STREAM WHILE STILL IN SAID COLUMN WITH DIMETHYLFORMAMIDE AT A POINT AT WHICH SAID HYDRATES WOULD NORMALLY TEND TO FORM IN THE ABSENCE OF SAID DIMETHYLFRMAMIDE IN A MANNER AND QUANTITY SUFFICIENT TO REMOVE ANY WATER FROM SAID OVERHEAD STREAM, RECOVERING SAID OVERHEAD STREAM AND CONDENSING AT LEAST A PORTION OF THE SAME, PASSING A PORTION OF CONDENSED ETHYLENE INTO SAID COLUMN AS REFLUX THEREFOR, AND REMOVING A STREAM OF DIMETHYLFORMAMIDE CONTAINING ANY WATER ABSORBED FROM SAID OVERHEAD STREAM AT A LEVEL SUBSTANTIALLY BELOW THE PLACE OF SAID CONTACTING OF THE DMF WITH SAID OVERHEAD STREAM.

Claim 2

A METHOD OF SEPARATING ETHYLENE FROM A STREAM CONTAINING IT, ETHANE, AND WATER AS AN IMPURITY WHICH COMPRISES FEEDING SAID STREAM TO A FRACTIONATION COLUMN BEING OPERATED AT A TEMPERATURE AT WHICH HYDRATES OF EHTYLENE WILL FORM, PRODUCING AND REMOVIG FROM SAID COLUMN AN OVERHEAD STREAM CONSISTING ESSENTIALLY OF ETHYLENE, CONTACTING SAID OVERHEAD STREAM WHILE STILL IN SAID COLUMN WITH DIMETHYLFORMAMIDE AT A POINT AT WHICH SAID HYDRATES WOULD NORMALLY TEND TO FORM IN THE ABSENCE OF SAID DIMETHYLFRMAMIDE IN A MANNER AND QUANTITY SUFFICIENT TO REMOVE ANY WATER FROM SAID OVERHEAD STREAM, RECOVERING SAID OVERHEAD STREAM AND CONDENSING AT LEAST A PORTION OF THE SAME, PASSING A PORTION OF CONDENSED ETHYLENE INTO SAID COLUMN AS REFLUX THEREFOR, AND REMOVING A STREAM OF DIMETHYLFORMAMIDE CONTAINING ANY WATER ABSORBED FROM SAID OVERHEAD STREAM AT A LEVEL SUBSTANTIALLY BELOW THE PLACE OF SAID CONTACTING OF THE DMF WITH SAID OVERHEAD STREAM.