The invention discloses a
propane pre-cooling double-mixing
refrigerant serial-connection
liquefaction system, which comprises a pre-cooling cold box a, a pre-cooling cold box b, a
liquefaction cold box a, a
liquefaction cold box b, a deep-cooling cold box a, a deep-cooling cold box b, a
propane pre-cooling circulating mechanism, a mixed
refrigerant liquefaction circulating mechanism and a mixed
refrigeration deep-cooling circulating mechanism, wherein the
propane pre-cooling circulating mechanism comprises a three-grade compression unit; the mixed
refrigerant liquefaction circulating mechanism comprises a first-grade compression unit; and the mixed
refrigeration deep-cooling circulating mechanism comprises a first-grade compression unit. The liquefaction
system provided by the invention adopts the propane pre-cooling double-mixing refrigerant parallel-connection
refrigeration mode, and liquefaction and undercooling circulation respectively adopt independent mixing refrigerant refrigeration circulation; the power distribution of three compressor units (one pre-cooling circulation compressor, one liquefaction circulation compressor and one undercooling circulation compressor) is effectively balanced; the limitation on that the
processing capability of the whole liquefaction device is affected because one compressor has too large power can be broken through; and meanwhile the maneuverability of the device can be improved.