Fractionation of Atmospheric Residue

An atmospheric residue from heavy crude oil was used in order to obtain different fractions by means of chromatographic separation. Table 5.1 shows the properties of the heavy crude and its atmospheric residue. Asphaltenes were obtained by precipitation with -heptane in a pressurized system (25kg/cm ), with nitrogen as inert at temperature of 60°C and constant stirring. SARA fractionation was carried out in two chromatographic columns packed with clay and alumina. More details about the fractionation procedure are reported elsewhere (Alvarez et al., 2011). 

Once the saturate, aromatic, resin, and asphaltene fractions were recovered, TGA was carried out on each fraction. The atmospheric residue was also analyzed by TGA. The temperature ranged from ambient up to 800°C. Aromatics, resins, asphaltenes, and atmospheric residue were analyzed at three different heating rate temperatures, i.e., 8°C/min, 12°C/min, and 16°C/min to obtain kinetic parameters toward coke formation, while for saturates only one heating rate (8°C/min) was used due to its propensity to ease thermal decomposition. 

Modeling of Processes and Reactors for Upgrading of Heavy Petroleum 

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FIGURE 5.3 Volatile fraction of atmospheric residue, asphaltenes, and resins at different heating rates. 

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