A cryogenic system for recovering a gas product stream and a liquid product stream from a hydrocarbon gas stream is provided which operates at process temperature of -50.degree. F. or less. A portion of a refrigerating liquid stream and a cooled liquid stream produced during operation of the cryogenic system are passed heat exchange relationship with an inlet vapor stream and define a partially closed refrigeration loop. The partially closed refrigeration loop permits the low process temperatures to be achieved.