LNG接收站蒸发计算状态方程选择

LNG物性参数是LNG接收站模型建立、工艺流程模拟计算及研究必不可少的基础数据。以国外实验数据为基础，采用Aspen HYSYS软件分析评价PR、SRK、LKP、BWRS状态方程对气液相组成、焓、密度等物性参数的预测结果，比选汽液相平衡和热力学参数的计算状态方程，建立了LNG接收站储罐蒸发模型，并比较了四种状态方程的准确度。结果表明：PR方程在汽液相平衡计算方面计算精度最高，相对误差为4.70%；LKP方程计算热力学参数最准确，预测误差为2.59%。综合考虑相平衡参数和热力学参数计算精度，PR方程精度最高，预测误差为3.77%。此外，PR方程对LNG储罐蒸发和储罐压力的模拟计算值与现场数据吻合度最好，因此LNG接收站蒸发计算推荐选用PR方程。研究结果对物性参数和LNG接收站蒸发计算状态方程的选择具有借鉴意义。

Selection of state equations for evaporation calculation in LNG receiving terminal

LNG physical parameters are the basis for the establishment of LNG receiving terminal model, process simulation calculation. Based on foreign experimental data, Aspen HYSYS software was used to analyze and evaluate the prediction accuracy of physical parameters such as density, enthalpy, and dew point of PR, SRK, LKP and BWRS equations, and evaluate the gas-liquid equilibrium and thermodynamic parameters calculation model. The tank evaporation model of the LNG receiving terminal was established to compare the accuracy of the four equations of state. The results showed that the PR equation had the highest prediction accuracy in the calculation of gas-liquid phase equilibrium, and the relative error was 4.70%. The most accurate thermodynamic parameters were calculated by LKP equation, and the prediction error was 2.59%. Considering the calculation accuracy of thermodynamic parameters and phase equilibrium parameters, the PR equation had the highest precision and the prediction error was 3.77%. In addition, the simulation results of evaporation and tank pressure by PR equation are in good agreement with the field data. Therefore, PR equation is recommended for evaporation calculation of LNG receiving station. The research results are useful for the selection of physical parameters and the equation of state for evaporation calculation of LNG receiving station.