A Temperature prediction model for high pressure natural gas through chokes

摘要

This study developed a downstream temperature prediction model for the high pressure natural gas flowing through chokes based on the iso-enthalpy choke theory. Considering the phase change during the choke process, the Lee-Kesler equation of state (EoS) and SRK EoS were utilized to calculate the enthalpies and liquid-vapor phase equilibrium respectively. Pseudocritical properties of mixtures, which are obtained by mixing rules, are very important in the enthalpy model, so the combinations of Lee-Kesler, Plocker-Knapp, Wong-Sandlere, and Prausnitz-Gunn mixing rules for LK EoS were researched, and the combination mixing rules with satisfactory accuracy for high pressure natural gases were proposed. The applications show the average absolute errors between the measured and predicted downstream temperatures are expected for less than 2℃ by using the model.