Effect of Reactor Configuration on the Hydrotreating of Atmospheric Residue

To study the effect of reactor configuration on hydrotreating, a series of experiments was carried out in a pilot plant equipped with two reactors in series that can operate in two modes: a fixed-bed reactor (FBR) or an ebullated-bed reactor (EBR). The experiments were carried out with the atmospheric residue as feedstock and commercial catalysts at a pressure of 100 kg/cm2 and temperatures of 380 and 400 °C. The highest conversions were obtained for the EBR–EBR (35.67–52.21%) and EBR–FBR (29.08–53.09%) configurations, unlike the FBR–FBR configuration that exhibited the lowest conversion (15.42–27.34%). At 400 °C, the EBR–FBR and FBR–FBR configurations showed higher hydrodemetalization than the others (81.00 and 76.95%, respectively). It was confirmed that the formation of sediments increases at high temperatures, whereas at 400 °C, it begins to be significant for the EBR–FBR and EBR–EBR configurations (0.010–0.767 and 0.041–0.613 wt %, respectively), in contrast to the FBR–FBR configuration that presented lesser formation of sediments (0.003–0.009 wt %).