A device and process for the conversion of aromatic compounds, includes/uses: a unit for the separation of the xylenes suitable for treating a cut comprising xylenes and ethylbenzene and producing an extract comprising para-xylene and a raffinate; an isomerization unit suitable for treating the raffinate and producing an isomerate enriched in para-xylene which is sent to a fractionation train; a pyrolysis unit suitable for treating biomass, producing a pyrolysis effluent feeding, at least partially, the feedstock, and producing a pyrolysis gas comprising CO and H2; a Fischer-Tropsch synthesis reaction section suitable for treating, at least in part, the pyrolysis gas, producing a synthesis effluent sent, at least in part, to the pyrolysis unit.