A Novel Process for Natural Gas Liquids Recovery from Oil Field Associated Gas with Liquefied Natural Gas Cryogenic Energy Utilization

A novel process to recovery natural gas liquids from oil field associated gas with liquefied natural gas (LNG) cryogenic energy utilization is proposed. Compared to the current electric refrigeration process, the proposed process uses the cryogenic energy of LNG and saves 62.6% of electricity. The proposed process recovers ethane, liquid petroleum gas (propane and butane) and heavier hydrocarbons, with total recovery rate of natural gas liquids up to 96.8%. In this paper, exergy analysis and the energy utilization diagram method (EUD) are used to assess the new process and identify the key operation units with large exergy loss. The results show that exergy efficiency of the new process is 44.3%. Compared to the electric refrigeration process, exergy efficiency of the new process is improved by 16%. The proposed process has been applied and implemented in a conceptual design scheme of the cryogenic energy utilization for a 300 million tons/yr LNG receiving terminal in a northern Chinese harbor.