A simulation on Aspen Plus for the synthesis of synthetic fuels and waxes is carried out. A 3MWth dual fluidized bed gasifier (DFBG) is employed to produce a syngas and it is fed with digestate or pine wood: the first biomass is the real investigation of the work while the latter is used as a reference. The mass flow of steam used in the gasification process is varied to keep the H2/CO ratio around 2. The syngas is cleaned removing sulfur compounds, ammonia and chlorine by wet scrubbers, the CO2 is removed by a pressure swing adsorption (PSA). The Fischer-Tropsch synthesis process (FTS) is simulated adopting the Anderson-Schulz-Flory model (ASF) with a chain-growth probability as a function of the temperature and H2/CO ratio.