Abstract: Taking the shallow condensing unit of Daqing Oilfield Natural Gas Company as an example, the current cold energy recovery situation of light hydrocarbon and export dry gas of shallow condensing unit was analyzed. Some existed problems and measures of improvement were put forward. Various schemes for improvement were compared based on the simulation computations by HYSIM software. Finally, a cold energy recovery process using multi-flow heat exchanger was proposed. After adopting said optimized process, when the recovery temperature of light hydrocarbon and export dry gas was 10℃, 263.6 MJ/h of cold energy could be recovered, the temperature of rich natural gas was decreased to -1.94℃ from 5℃, the load of ammonia evaporator reduced by 20.4％, the annual saving of electricity and production cost reached 60.61×104 kWh and 0.477 MRMB, respectively.

Key words: natural gas, shallow condensing unit, cold engergy recovery, multi-flow heat exchanger, optimization