PHASE-BEHAVIOR OF CO2 CRUDE-OIL MIXTURES IN SUPERCRITICAL-FLUID EXTRACTION SYSTEM - EXPERIMENTAL-DATA AND MODELING

Continuous multiple-contact extractions of a crude oil were carried ou t with supercritical CO2 in order to assess the effect of the density and critical point of a solvent on the extraction performance as a fun ction of process variables. Most of the extraction performance was sol vent density dependent. In the vicinity of the critical point of CO2, however, the solvent density was not the only parameter that governed extraction yields. The results of simulated distillation and gas chrom atography-mass spectrometry analyses of extracts represented that the earlier extracts contained lighter compounds and the latter extracts c ontained progressively heavier compounds. As the extraction proceeded, relatively greater amounts of paraffinic compounds and lesser amounts of naphthenic and aromatic compounds were extracted. This composition al change occurring during a dynamic extraction was also ascertained b y phase equilibrium calculations using the Soave-Redlich-Kwong equatio n of state and a component-lumping procedure.