The Joule-Thomson effect in natural gas flow-rate measurements

A numerical procedure for the calculation of the Joule-Thomson (JT) coefficient of a natural gas is derived. The AGA-8 extended virial-type characterization equation is used to calculate the rate of change of the compression factor with respect to the temperature at constant pressure. The DIPPR/AIChE generic ideal heat capacity equations are used to derive the molar heat capacity of a natural gas mixture. The accuracy of the natural gas flow-rate measurements, based on differential devices, is analysed with respect to the temperature drop, characterized by the JT effect. The results obtained are illustrated graphically. The procedure derived enables compensation for the JT effect in natural gas flow-rate measurements.