A side-rectifier DWC (divided wall column) is proposed to replace the whole FLNG (floating liquefied natural gas) plant, which comprises of three distillation columns in the conventional system. The proposed column is compact equipment suitable to harsh offshore operation of the gas plant, which is operated at low pressure to reduce the investment and electricity costs. The economics, thermodynamic efficiency and operational difficulty of the side-rectifier DWC are evaluated and compared with the conventional system. The heating and cooling duties of the side-rectifier DWC are 5.9% and 5.1% less than those of the conventional system, respectively. The economic evaluation indicates that the side-rectifier DWC requires 57% less investment and 10% more utility cost than the conventional system. However, low feed pressure used in the side-rectifier DWC saves the compressor cost of 5.1 times the investment cost and the electricity cost of 1.8 times the total utility cost of the high-pressure conventional system. (C) 2014 Elsevier B.V. All rights reserved.