LNG接收站蒸发气再冷凝工艺改进及性能分析

Improvement and property analysis of BOG recondensation process at LNG receiving terminal

以国内某LNG接收站为例,利用HYSYS对蒸发气(Boil Off Gas,BOG)再冷凝工艺进行了模拟,在热力学分析基础提出了BOG多级压缩再冷凝工艺,并分析了性能参数对工艺能耗的影响,以此为根据提出了改进措施。经分析:多级压缩再冷凝工艺较典型的再冷凝工艺更为节能,可节约22.03%的能耗;压缩机压缩系数ri及BOG分流比xi对流程中压缩机能耗影响较大,可通过适当减小压缩系数ri与增大BOG分流比xi的方法来减少压缩机的能耗;外输LNG温度、压力对气化器、海水泵及外输泵的能耗影响较为明显,适当降低外输LNG温度与压力,能够有效改善这3个设备单元能量利用效率。

Through thermodynamics-based analysis and improvement of BOG recondensation process at a domestic LNG receiving terminal by HYSYS, a BOG multi-stage compression and recondensation process model was established. And analyzing effect of the performance parameters of this process on the energy consumption is for the sake of proposing improved measures. The results showed that multi-stage compression and recondensation process was more saving than the traditional process （saving about 22.03%）;the ri of compressor and the xi of BOG split ratio had big influence on the compressor energy, and reducing the ri of compressor and increasing the xi of BOG split ratio suitably can low the compressor energy; the energy of gasifier, seawater pump and last pump affected obviously by the temperature and pressure of LNG, and reducing the temperature and pressure of LNG suit-ably can effectively improve the energy efficiency of them.