LIMITING DIFFUSION-COEFFICIENTS OF HEAVY MOLECULAR-WEIGHT ORGANIC CONTAMINANTS IN SUPERCRITICAL CARBON-DIOXIDE

A Taylor dispersion apparatus was designed and constructed for measuri ng diffusion coefficients in supercritical carbon dioxide. The limitin g mutual diffusion coefficients of naphthalene, phenanthrene, and hexa chlorobenzene were measured in the temperature range of 308-328 K and at pressures between 96.4 and 249 bar. The triple point volume for car bon dioxide extrapolated from the data closely matches its literature value. In addition, a simple correlation based on hard sphere theories was developed for prediction of diffusivities of heavy molecular weig ht organics in supercritical carbon dioxide.