ISOBARIC HEAT-CAPACITIES OF MULTICOMPONENT GASES BETWEEN 323 AND 423 K AND AT PRESSURES UP TO 25 MPA - COMPARISON WITH SOME EQUATIONS OF STATE

Isobaric heal capacities C-p have been measured, from 323 to 423 K at pressures from 5 to 25 MPa, by direct calorimetry for different gaseou s mixtures containing between 83 and 99% of methane and usually encoun tered in natural gas. The experimental technique has been calibrated a nd checked using pure gases such as nitrogen, helium, methane, carbon dioxide and argon. Experimental results were used to evaluate the perf ormance of five equations of state in the case of gaseous mixtures and of two equations of state for carbon dioxide and argon, respectively. The equation of state AGA 8 specially developed to represent pVT-prop erties of natural gas gives the best results, yielding C-p values whic h agree within +/- 2% with experimental data. (C) 1997 Elsevier Scienc e Ltd.