A system for cooling a gas with a mixed refrigerant including: a) a heat exchanger including a warm end and a cold end, the warm end having a feed gas inlet adapted to receive a feed of the gas and the cold end having a product outlet through which product exits said heat exchanger, said heat exchanger also including a cooling passage that extends between and is in communication with the feed gas inlet and the product outlet, a pre-cool liquid passage, a pre-cool refrigeration passage, a high pressure vapor passage, a high pressure liquid passage and a primary refrigeration passage; b) a suction separation device having a vapor outlet; c) a first stage compressor having a suction inlet in fluid communication with the vapor outlet of the suction separation device and an outlet; d) a first stage after-cooler having an inlet in fluid communication with the outlet of the first stage compressor and an outlet; e) an interstage separation device having an inlet in fluid communication with the outlet of the first stage after-cooler and having a vapor outlet in fluid communication with the high pressure vapor passage of the heat exchanger and a liquid outlet in fluid communication with the pre-cool liquid passage of the heat exchanger; f) a first expansion device having an inlet in fluid communication with the pre-cool liquid passage of the heat exchanger and an outlet in communication with the pre-cool refrigeration passage of the heat exchanger; g) a second expansion device having an inlet in fluid communication with the high pressure vapor passage of the heat exchanger and an outlet in communication with the primary refrigeration passage of the heat exchanger; h) said pre-cool refrigeration passage adapted to produce a mixed phase stream and said primary refrigeration passage adapted to produce a vapor stream; i) said suction separation device also in fluid communication with an outlet of the primary refrigeration passage of the heat exchanger so as to receive the vapor stream; j) a last stage compressor having a suction inlet in fluid communication with the vapor outlet of the interstage separation device and an outlet; k) a last stage after-cooler having an inlet in fluid communication with the outlet of the last stage compressor and an outlet; l) an accumulator separation device having an inlet in fluid communication with the outlet of the last stage after-cooler and a vapor outlet and a liquid outlet, said vapor outlet in fluid communication with the high pressure vapor passage of the heat exchanger and said liquid outlet in fluid communication with the high pressure liquid passage of the heat exchanger; and m) a third expansion device having an inlet in fluid communication with the high pressure liquid passage of the heat exchanger and an outlet in fluid communication with the primary refrigeration passage of the heat exchanger. a) a heat exchanger including a warm end and a cold end, the warm end having a feed gas inlet adapted to receive a feed of the gas and the cold end having a product outlet through which product exits said heat exchanger, said heat exchanger also including a cooling passage that extends between and is in communication with the feed gas inlet and the product outlet, a pre-cool liquid passage, a pre-cool refrigeration passage, a high pressure vapor passage, a high pressure liquid passage and a primary refrigeration passage; b) a suction separation device having a vapor outlet; c) a first stage compressor having a suction inlet in fluid communication with the vapor outlet of the suction separation device and an outlet; d) a first stage after-cooler having an inlet in fluid communication with the outlet of the first stage compressor and an outlet; e) an interstage separation device having an inlet in fluid communication with the outlet of the first stage after-cooler and having a vapor outlet in fluid communication with the high pressure vapor passage of the heat exchanger and a liquid outlet in fluid communication with the pre-cool liquid passage of the heat exchanger; f) a first expansion device having an inlet in fluid communication with the pre-cool liquid passage of the heat exchanger and an outlet in communication with the pre-cool refrigeration passage of the heat exchanger; g) a second expansion device having an inlet in fluid communication with the high pressure vapor passage of the heat exchanger and an outlet in communication with the primary refrigeration passage of the heat exchanger; h) said pre-cool refrigeration passage adapted to produce a mixed phase stream and said primary refrigeration passage adapted to produce a vapor stream; i) said suction separation device also in fluid communication with an outlet of the primary refrigeration passage of the heat exchanger so as to receive the vapor stream; j) a last stage compressor having a suction inlet in fluid communication with the vapor outlet of the interstage separation device and an outlet; k) a last stage after-cooler having an inlet in fluid communication with the outlet of the last stage compressor and an outlet; l) an accumulator separation device having an inlet in fluid communication with the outlet of the last stage after-cooler and a vapor outlet and a liquid outlet, said vapor outlet in fluid communication with the high pressure vapor passage of the heat exchanger and said liquid outlet in fluid communication with the high pressure liquid passage of the heat exchanger; and m) a third expansion device having an inlet in fluid communication with the high pressure liquid passage of the heat exchanger and an outlet in fluid communication with the primary refrigeration passage of the heat exchanger.