On the Joule-Thomson Effect for Gas Mixtures

Abstract

An investigation of the integrated isothermal and isenthalpic Joule-Thomson effect and also of the isothermal and adiabatic Joule-Thomson coefficient for gas mixtures has been performed. It is shown that the experimental results of the integrated isenthalpic effect for gas mixtures obtained by Koeppe are in agreement with the qualitative results from the van der Waals thermal equation of state. A special interest is devoted to the question whether the cooling effect for a given inlet state and a given exit pressure of the throttling device, can be larger for a binary mixture than for both of its constituents. It is found that this is possible and this result is confirmed for a mixture of nitrous oxide and ethylen by the experimental results of Charnley et al. The adiabatic and isothermal zero pressure Joule-Thomson coefficients are analyzed as functions of the composition for fixed temperature and the conditions for maxima and minima are stated. The results for the isothermal coefficient are in agreement with the measurements reported by Charnley et al. The Joule-Thomson coefficients have also been studied with the aid of the principle of corresponding states and an equation for the zero pressure isothermal Joule-Thomson coefficient following from this principle has been derived from the experimental values of this coefficient. Further it is shown that for gases obeying the principle of corresponding states a necessary condition for a minimum of the zero pressure isothermal Joule-Thomson coefficient considered as a function of composition for fixed temperature, is that one of the constituents has a larger critical temperature and a smaller critical molar volume than the other one.

Numerical Simulations of High CO2 Content Flows in Production Wells, Flowlines and Risers

“…The Joule-Thomson effect contribution to the total cooling of the mixture can be evaluated by the integral isenthalpic Joule-Thomson effect (Gustafsson, 1970;Maytal and Pfotenhauer, 2013), which can be defined as the temperature drop when the mixture is subject to a given decompression:…”

“…where indexes u and d denote upstream and downstream conditions, respectively, and JT is the isenthalpic Joule-Thomson coefficient, defined as (Gustafsson, 1970):…”