High pressure phase equilibria in methane plus waxy systems - 1. Methane plus heptadecane

Fluid-fluid and fluid-solid phase equilibrium were experimentally determined under pressure on the system methane + heptadecane using a full visibility cell. Measurements were performed using the synthetic method on mixtures ranging from pure heptadecane to 99% of methane. The liquid-solid phase transitions were investigated up to 90 MPa and fluid phase boundary was studied in the temperature domain from 293 to 373 K. The appearance of a minimum in the three phase (V-L-S) equilibrium curve is discussed and it is shown that the difference in the solid phase structure and the presence of a solid-solid phase transition do not affect significantly the phase diagram determined. (c) 2007 Elsevier B.V. All rights reserved.