Effects of natural gas compositions on its Joule-Thomson coefficients and Joule-Thomson inversion curves

The main goal of this study is to investigate the effect of natural gas composition on the Joule-Thomson coefficient and Joule-Thomson inversion curve. The Joule-Thomson inverse curve is the geometrical location of points where the Joule-Thomson coefficient is zero. The curve is an important parameter for the liquefaction capability of natural gas. The GERG-2008 equation of state is utilized to calculate the Joule-Thomson coefficient as well as the JT inversion curve. To validate the numerical values, the results are compared with measured values and the validation results show the GERG-2008 calculated Joule-Thomson inversion curve with high accuracy. The results show, that natural gases with larger molecular weights have higher pressures at the same temperature. Also, Based on GERG-2008 data, a novel correlation is presented for the calculation of the Joule-Thomson inversion curve. The correlation has an average absolute percent deviation of less than 2.5% in determining the natural gas Joule-Thomson inversion curve. It should be pointed out that for developing the correlation a huge database of 33,000 natural gas mixture is employed.