The invention relates to a method and apparatus for producing liquid hydro carbonaceous product (1) such as biofuel from solid biomass (2). The method comprises a gasifying step for gasifying solid biomass (2) in a gasifier (6) to produce raw synthesis gas (3), conditioning of the raw synthesis gas (3) to purify the raw synthesis gas (3) to obtain purified synthesis gas (4) having a molar ratio of hydrogen to carbon monoxide between 2.5 to 1 and 0.5 to 1, preferably to between 2.1 to 1 and 1.8 to 1, more preferably about 2 to 1, and subjecting purified synthesis gas (4) to a Fischer-Tropsch synthesis in a Fischer-Tropsch reactor (5) to produce liquid hydro carbonaceous product (1).