可提高效率及海上适应性的浮式双混合制冷剂天然气液化工艺

摘要

The LNG Floating Production Storage and Offioading (LNG-FPSO) unit is movable,reliable and safe,but less adaptable to offshore conditions.In view of this,the Technology R&D Center of CNOOC Gas & Power Group developed a floating DMR (dual mixed refrigerant) LNG process and conducted a process simulation.They worked together with China University of Petroleum to develop an experimental device.With this device,DMR modular design and operation parameter optimization are realized by using two mixed refrigerants with different proportions,and the efficiency and offshore adaptability of LNG-FPSO technology are improved.Meanwhile,the equipment suitable for offshore complex conditions was selected for the experiment of DMR process.Error analysis was performed on the key parameters such as the outlet and inlet pressure,the temperature of the water cooler and the control scheme was determined;besides,the actual operation parameters of the process were confirmed through experiments,providing experience for equipment selection and operation in the actual production of LNG-FPSO.Finally,the sensitivity of this process to the temperature,pressure,flow rate and component content of natural gas was analyzed.The parameter variation range of this process suitable for the production is also presented.It is concluded that this process is adaptable to complex offshore conditions and large-scale natural gas liquefaction.%浮式天然气液化装置(LNG Floating Production Storage and Offloading Unit,缩写为LNG-FPSO)具有便于迁移、设备可靠、安全性高等优点,但其海上适应性较差.为此,中海石油气电集团有限责任公司技术研发中心研发了一种浮式双混合制冷剂的天然气液化工艺流程,进行了流程模拟并与中国石油大学(华东)合作建造了实验装置;通过利用不同配比的两种混合冷剂实现DMR模块化设计及流程运行参数的优化,提高了LNG-FPSO工艺的效率及海上适应性.同时选择适应于海上复杂工况的设备进行双混合制冷剂流程的实验,并针对压缩机出、入口压力、水冷器温度等关键参数进行误差分析以及控制方案的确定,通过实验确定了流程中实际操作参数,为LNG-FPSO实际生产中的设备选型和运行提供了经验.最后分析了该工艺对原料气温度、压力、流量以及组分含量的敏感性,并给出了该工艺在生产中适应的参数变化范围.结论认为:该工艺可适应于复杂的海况并进行大规模的天然气液化处理.