The Fischer-Tropsch synthesis carried out in a slurry bubble column is modeled with a focus on the production of liquid fuels from biomass. Mass, momentum and energy balances are formulated for the gas, liquid and solid phases and solved by the orthogonal collocation method. A multifluid population balance model is utilized. The interfacial area between the gas and liquid phases can be calculated directly from a mass density function of the bubbles. Five different compositions of feed synthesis gas representing biomass (with and without water-gas shift reaction), coal (with and without autothermal reforming), and natural gas (after autothermal reforming) are simulated to highlight the effect of the synthesis gas composition.