BACKGROUND: The FischerTropsch process is the most important path for converting natural gas to high quality liquid hydrocarbons. Low temperature FischerTropsch synthesis in slurry bubble column reactors with cobalt-based catalysts is used for mid-distillates production. RESULTS: In this work the slurry bubble column reactor was simulated by applying the two-bubble class mathematical model. In addition, the effect of operating parameters on synthesis gas conversion was studied. The distribution of products was also predicted from the simulation framework. CONCLUSIONS: The effect of synthesis gas inlet velocity on mid-distillates production rate was studied in the present work. A maximum production rate for mid-distillates of about 23 kg s(-1) was predicted from the simulation program. (C) 2011 Society of Chemical Industry