晃荡条件下氮膨胀液化过程冷箱运行可靠性

Reliability experiments in a cold box with nitrogen expansion liquefaction process running under sloshing conditions

为了验证LNG-FPSO液化工艺及其核心设备——液化冷箱在海上晃荡条件下运行的可靠性,建造了小型撬装天然气液化装置,并通过冷箱的纵荡和横摇实验,对不同工况下板翅式换热器、膨胀机和分离器的工作性能及整体工艺系统的运行效果进行了分析。结果表明,晃荡条件下冷箱运行可靠,设备具有较强的抗晃动能力,带预冷的氮膨胀液化工艺可以适用于目标气田的海况;膨胀机水平安装可以减小晃荡的影响;横摇会提高气液两相分离过程的平衡程度及液相的蒸发率;横摇是对FPSO装置影响最大的运动形式,将工艺设备布置在船体的中轴线上可以减小设备晃荡的幅度。

A small-scale natural gas liquefaction equipment was built to study the liquefaction process of LNG-FPSO and the running reliability of liquefaction cold box under sloshing conditions at sea,which is the core equipment of the LNG-FPSO.The working performance of plate-fin heat exchanger,expander and separator and the operation effect of the whole process system under different working conditions were analyzed by the surge and roll experiments of the cold box.The main conclusions are summarized as follows： the cold box and the equipment run well under the experimental sloshing conditions and the pre-cooling nitrogen expansion liquefaction process is suited to the sea condition of the target gas field;the expander installed horizontally can reduce the effect of sloshing;the balance level of the gas-liquid two-phase separation process and the evaporation rate of liquid phase is increased by rolling;arranging the process equipment at the medial axis of the ship can reduce the amplitude of sloshing,as the roll is the most influential motion on the FPSO unit.