We develop a strategy for scaling up a bubble column slurry reactor, which is used for example for carrying out the Fischer-Tropsch synthesis reaction. The strategy involves development of a proper description for the large bubble swarm velocity in highly concentrated paraffin-oil slurries in columns of varying diameters. The developed relationship is incorporated into an Eulerian simulation code which is then used to predict the hydrodynamic parameters (hold-up, velocity distribution, etc.) for reactors of commercial scale.