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

Abstract

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.