Low Vapor Pressure (down to 10-6 Pa) Determination of 12 Anthropogenic Polycondensed Hydrocarbons Using Dynamic Saturation Apparatus with Online Detection

Knowledge of data describing phase equilibria of key compounds contained in petroleum and coal liquids is of major interest for modeling the behavior of reservoir and coal fluids over a wide range of temperatures and pressures. While abundant data of reasonable accuracy are accessible for components of low and medium molar mass, less reliable information is available for characterizing high boiling fractions containing considerable amount of polycondensed hydrocarbons. Verified data for compounds of high molar mass are obviously needed for better characterization of reservoir fluids.

The aim of our work is to present the vapor and sublimation pressures of a series of Polycyclic Aromatic Hydrocarbons, PAH, (1,2,3,4, Dibenzanthracene, benzo(k) fluoranthene (a,c), Chrysene, 1,2 Benzanthracene, Coronene, 1,2,5,6, Dibenzanthracene (a,h), 1,2,7,8 Dibenzanthracene (a,j), Benzo(b) fluoranthene, Ovalene, etc). The measurements were carried out by a gas saturation method. The used apparatus has been designed and developed in our laboratory. The principle is based on relative method using a reference compound along with the sample. Experimental measurements were made for 12 PAH having 3 to 9 arenes. The pressure ranged from 100 Pa to 5.10-6 Pa corresponding to an interval of temperatures between 295 K to 513 K. The validation of the apparatus and the procedure in the quoted pressure range were carried out by studying normal alkanes (hexadecane and eicosane) and phenanthrene (aromatic compound with 3 arenes). The experimental results showed an excellent agreement with the available literature values: standard deviation of 5.5 % overall the studied temperature range. In a second step, the collected data were used to perform a cubic type equation of state based on a group contribution method.