LNG接收终端工艺流程动态仿真

Dynamic simulation of LNG import terminal process

LNG接收终端的主要功能是接收、储存和再汽化LNG,并通过天然气管网向电厂和城市用户供气。通过建立接收终端各设备的动态模型,增加了必要的控制系统,对流程进行了动态仿真,针对接收终端季节调峰、卸船和储罐超压3种工况进行了案例分析,得到了以下结论:接收终端调峰期间,外输泵、罐内泵功耗变化规律与外输天然气流量变化规律一致;卸船工况主要对压缩机功耗、再冷凝器入口BOG及LNG流量有影响,整个卸船过程一般需要13h左右;储罐超压过程中,由于压缩机负荷的调节,对压缩机功耗、再冷凝器压力、再冷凝器入口BOG及LNG流量有较大影响,整个超压事故持续时间为15.2h;对接收终端工艺的设计和运行提出了建议。

The main function of the LNG import terminal is LNG receiving, storage and re-gasification, then supplying natural gas to power plants and city users by pipelines. Through building the dynamic models of each equipment in the LNG import terminal, and adding the necessary control systems, the process was simulated in dynamic mode, and then three operation conditions of the LNG import terminal were analyzed, including seasonal peak shaving, ship unloading and tank overpressure. During the peak shaving of LNG terminal, the power consumption of LNG send-out pump and in-tank pump changed with the same trend as the flow rate of export nature gas. Compressor power consumption and inlet flow rate of re-condenser, including BOG and LNG were affected by the ship unloading condition, which spent 13 h for the entire process. During the tank overpressure accident, which spent 15.2 h for the entire process, compressor power consumption, re-condenser pressure and inlet flow rate of re-condenser changed with the adjustment of compressor load. Finally, some suggestions on the design and operation of the LNG import terminal were proposed.