Adsorption of Polycyclic Aromatic Hydrocarbons from Heavy Naphthenic Oil Using Commercial Activated Carbons. 2. Column Adsorption Studies

Abstract

Continuous adsorption and desorption of polycyclic aromatic hydrocarbons (PAHs) from heavy naphthenic oils (HNOs) were performed using commercial activated carbon on fixed bed experiments. In part 1, HNO samples with high PAH content (ca. 8 wt %) were treated in batch adsorption experiments, showing decrease in PAH concentration to ca. 3%. In this study, successive column experiments were carried out to study the reduction in capacity along continuous cycles and optimal operational conditions. A column simulation model, using the particle parameters obtained in the previous study, was applied to predict breakthrough curves for adsorption and desorption runs. After several cycles of adsorption/desorption, using solvent or inert gas, only a slight decrease in PAH adsorption capacity was observed. Selectivities for PAH adsorption in relation to aromatics adsorption were also estimated from the adsorption breakthrough curves data. A conceptual continuous process was simulated using the proposed model and evaluated based on productivity in terms of volume of treated oil per mass of adsorbent per time, showing a maximum value at space velocity of ca. 4 h–1.