This invention is an improved distillation sequence for the separation and
purification of ethylene from a cracked gas. A hydrocarbon feed enters a
C2 distributor column. The top of the C2 distributor column is thermally
coupled to an ethylene distributor column, and the bottoms liquid of a C2
distributor column feeds a deethanizer column. The C2 distributor column
utilizes a conventional reboiler. The top of the ethylene distributor is
thermally coupled with a demethanizer column, and the bottoms liquid of
the ethylene distributor feeds a C2 splitter column. The ethylene
distributor column utilizes a conventional reboiler. The deethanizer and
C2 splitter columns are also thermally coupled and operated at a
substantially lower pressure than the C2 distributor column, the ethylene
distributor column, and the demethanizer column. Alternatively, a
hydrocarbon feed enters a deethanizer column. The top of the deethanizer
is thermally coupled to an ethylene distributor column, and the ethylene
distributor column utilizes a conventional reboiler. The top of the
ethylene distributor column is thermally coupled with a demethanizer
column, and the bottoms liquid of the ethylene distributor column feeds a
C2 splitter column. The C2 splitter column operates at a pressure
substantially lower than the ethylene distributor column, the
demethanizer column, and the deethanizer column.