Hydrodynamics and Heat-Transfer Characteristics of H2-Vacuum Residue Slurry Bubble Column Reactor

The hydrogen-vacuum residue (H₂-VR) slurry bubble column reactor (SBCR) with catalytic hydrocracking reactions was carried out in a pilot-scale SBCR under 160 bar and 425 ºC. The total gas holdup () was experimentally measured in the H₂-VR SBCR with 2 m height and 0.05 m inner diameter, which was operated at a superficial gas and liquid velocities of 6.4 and 0.27 mm/s, respectively. A two-phase Eulerian computational fluid dynamics (CFD) model coupled with the population balance equation (PBE) was developed for the H₂-VR SBCR. A reaction-mixture model was proposed to predict the physical properties varying with catalytic hydrocracking reactions along the reactor height. In order to calculate the momentum-transfer between two phases, the ratio of the drag coefficient to the bubble size was estimated based on the force balance for a rising bubble, and the swarm correction factor was integrated. The predicted by the CFD-PBE model was 6%, which was comparable to experimental data (6.6%). The bubble size and specific surface area were estimated to be 1.2 mm and 300 m²/m³, respectively. The temperature was distributed evenly in both axial and radial directions, except near the bottom.