PHASE-BEHAVIOR OF AN ASYMMETRIC TERNARY MIXTURE IN THE NEAR-CRITICAL REGION

The phase behavior of an asymmetric ternary mixture composed of methan e, n-butane and n-octane has been systematically studied in the near-c ritical region. The experimental work was performed by using a compute r-controlled, dual-cell high-pressure PVT unit (made by ROP Corporatio n, France) equipped with video camera-monitor-recorder system and on-l ine Anton-Paar fluid density meter. The experimental measurements invo lve the compressibility factor of the compressed fluid, the bubble/dew point locus in the near-critical region, the mixture critical point, the liquid volume fraction in the two-phase region, and the compositio n-density data of the coexisting equilibrium phases. Such systematic d ata are scarce in the open literature, and are valuable for testing th e performance of an equation of state/mixing rule in the near-critical region. The volume-translated Soave-Redlich-Kwong equation of state p roposed by Peneloux and Rauzy (Fluid Phase Equilibria, 1982) was used to predict the experimental data and the results being evaluated. Copy right (C) 1996 Elsevier Science Ltd.