A method is described for refrigerant supply of a low-temperature
separation stage in a plant for producing olefins from
hydrocarbon-containing feed (olefin plant). During the separation
sequence beginning with a front end deethanizer (3) downstream of raw gas
compressor (1), precooler and dryer (2), first separation is performed
into an olefin fraction having at most two carbon atoms and an olefin
fraction having at least three carbon atoms. The fraction having at least
three carbon atoms is conducted to the further separation sequence for
longer-chain olefins (4). The fraction having at most two carbon atoms is
conducted via a catalytic hydrogenation stage (5) connected in between to
the low-temperature separation stage (6) which comprises three
condensation stages in the temperature range from -50.degree. C. to
-100.degree. C. From the low-temperature separation stage, gaseous
hydrogen (9) and methane (10) are drawn off, while the olefins having at
most two carbon atoms are conducted to a further fractionation stage (7).
The refrigeration power for the low-temperature separation stage is
provided by the vaporization via heat exchangers of a portion of the
liquid ethylene fraction (8) resulting in the front end deethanizer. The
vaporized ethylene fraction is recirculated to the raw gas compressor
(11).