China depends on naphtha (derived from oil) as the main feedstock for ethylene plants, resulting in margins that are negatively co-related with the price of oil. Clearly, light hydrocarbons provide cost advantages over the conventional naphtha feedstock. Consequently, the recovery of light hydrocarbons from refinery gas has been gathering more and more significance. Nonetheless, the cryogenic separation needs low process temperatures, substantially increasing the refrigeration load requirements and, attendantly, the compression requirements associated with the refrigeration system. In this paper, the cold energy of liquefied natural gas (LNG) is applied to light hydrocarbons cryogenic separation process to replace the compression refrigeration system on the basis of one China refinery. The results show that LNG can provide 14,373 kW cold energy for the separation process, resulting in a direct compression power saving of 7973 kW and making the utilization rate of LNG cold energy as high as 71.9%. (C) 2014 The Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.