A refrigeration system for cooling a charge gas by a binary refrigerant, comprising: n heat exchangers (H-201, H-202, H-203, H-204, H-205) for progressively cooling the charge gas by the binary refrigerant, wherein n is an integer of at least 2, wherein the refrigerant is successively fed to the first to the nth heat exchanger, wherein a portion of the refrigerant is expanded to lower the temperature after each of the n heat exchangers (H-201, H-202, H-203, H-204) to provide first to nth expanded refrigerants (2502, 2503, 2504, 2505), wherein each of the expanded refrigerants is fed back to the series of heat exchangers (H-201, H-202, H-203, H-204) such that the kth expanded refrigerant (2502, 2503, 2504, 2505) is successively fed back to the kth to the first heat exchangers (H-204, H-203, H-202, H-201) to provide cooling and result in kth heated refrigerant (2410, 2308, 2206, 2104), wherein k is an integer of 1 to n, wherein the heated refrigerants (2410, 2308, 2206, 2104) have temperatures of 0 °C to 25 °C, n compressor stages (K-211, K-212, K-213, K-214) for compressing the heated refrigerants (2410, 2308, 2206, 2104) arranged such that the output from the mth compressor stage (K-211, K-212, K-213) is fed to the (m+1)th compressor stage (K-212, K-213, K-214) after being cooled by a respective interstage cooler (H-211, H-212, H-213), wherein m is an integer of 1 to (n-1), and the output from the nth compressor stage is fed to the nth interstage cooler (H-214), at least one separator (V-201, V-202, V-203) following one of the heat exchangers (H-202, H-203, H-204) for separating the cooled charge gas from said heat exchanger to produce an overhead (2005, 2008, 2011) to be fed to the subsequent heat exchanger and a bottoms (2004, 2007, 2010), and a demethanizer (C-201) for separating the bottoms (2004, 2007, 2010) from the at least one separator into an overhead comprising methane and a bottoms comprising C2+ hydrocarbons; wherein the charge gas from the nth heat exchanger (H-204) is separated into a stream of H 2 and a stream of methane and each of the streams is successively fed back to the nth to the 1st heat exchangers after the stream of H 2 is cooled. n heat exchangers (H-201, H-202, H-203, H-204, H-205) for progressively cooling the charge gas by the binary refrigerant, wherein n is an integer of at least 2, wherein the refrigerant is successively fed to the first to the nth heat exchanger, wherein a portion of the refrigerant is expanded to lower the temperature after each of the n heat exchangers (H-201, H-202, H-203, H-204) to provide first to nth expanded refrigerants (2502, 2503, 2504, 2505), wherein each of the expanded refrigerants is fed back to the series of heat exchangers (H-201, H-202, H-203, H-204) such that the kth expanded refrigerant (2502, 2503, 2504, 2505) is successively fed back to the kth to the first heat exchangers (H-204, H-203, H-202, H-201) to provide cooling and result in kth heated refrigerant (2410, 2308, 2206, 2104), wherein k is an integer of 1 to n, wherein the heated refrigerants (2410, 2308, 2206, 2104) have temperatures of 0 °C to 25 °C, n compressor stages (K-211, K-212, K-213, K-214) for compressing the heated refrigerants (2410, 2308, 2206, 2104) arranged such that the output from the mth compressor stage (K-211, K-212, K-213) is fed to the (m+1)th compressor stage (K-212, K-213, K-214) after being cooled by a respective interstage cooler (H-211, H-212, H-213), wherein m is an integer of 1 to (n-1), and the output from the nth compressor stage is fed to the nth interstage cooler (H-214), at least one separator (V-201, V-202, V-203) following one of the heat exchangers (H-202, H-203, H-204) for separating the cooled charge gas from said heat exchanger to produce an overhead (2005, 2008, 2011) to be fed to the subsequent heat exchanger and a bottoms (2004, 2007, 2010), and a demethanizer (C-201) for separating the bottoms (2004, 2007, 2010) from the at least one separator into an overhead comprising methane and a bottoms comprising C2+ hydrocarbons; wherein the charge gas from the nth heat exchanger (H-204) is separated into a stream of H 2 and a stream of methane and each of the streams is successively fed back to the nth to the 1st heat exchangers after the stream of H 2 is cooled.