The Fischer-Tropsch reactor is sectioned into stages based on the systematic method given by Hillestad (2010). The design functions are optimized to maximize the concentration of C11+ at the end of reactor path. The decision variables are fluid mixing, hydrogen distribution, heat transfer area distribution, coolant temperature, and catalyst concentration. With the path temperature constrained by 250 degrees C, staging of the reactor will increase the concentration of C11+. For a three-stage reactor, the concentration is increased by 2.50% compared to a single-stage reactor. The optimal mixing structure is plug flow to have the maximum possible conversion. A case study is conducted to separate and distribute hydrogen along the reactor path. This will reduce H-2/CO at the beginning of the path and increase chain growth probability. The results show that for a three-stage reactor, the concentration of C11+ is increased by 15.93% compared to single-stage reactor. (c) 2011 Elsevier Ltd. All rights reserved.