A process for batch wise production of bio-oil comprising the steps of a) preparing a black liquor composition comprising kraft black liquor, and having a hydroxide ion concentration of 1-40 g/l, preferably 5-15 g/l based on the volume of black liquor, if necessary adjusting the hydroxide ion concentration by means of addition of an acidifying agent; b) reacting the black liquor composition in a reactor and reacting the black liquor composition at 220-350 °C for 10-120 minutes, preferably 30-60 minutes in the absence of a solid catalyst; or at 180-240 °C for 10-120 minutes, preferably 30-60 minutes, in the presence of a solid catalyst, thereby causing depolymerization of lignin in the black liquor; c) cooling the composition to a temperature below the boiling point of a solvent to be added in a subsequent step; d) acidifying the composition by adding one or more acidifying agents until a pH of 4-5 is reached; e) adding a solvent to the composition, in order to extract oil from the composition; f) separating the composition by phase separation in a first separation step into - an oil phase comprising solvent, oil, and organic acids, - a first water phase comprising water, salts, and non-depolymerized lignin solids, - a second water phase comprising water and salts; g) filtering the first phase to remove any particles; h) desalting the filtered oil phase by I) washing it by adding water and separating by phase separation in a second separation step into - an oil phase comprising oil and solvent, - a third water phase comprising salts; or II) adding adsorbent and/or absorbent material or ion exchange material, or combinations thereof; i) evaporating the solvent comprised in the oil phase, thus obtaining a bio-oil. a) preparing a black liquor composition comprising kraft black liquor, and having a hydroxide ion concentration of 1-40 g/l, preferably 5-15 g/l based on the volume of black liquor, if necessary adjusting the hydroxide ion concentration by means of addition of an acidifying agent; b) reacting the black liquor composition in a reactor and reacting the black liquor composition at 220-350 °C for 10-120 minutes, preferably 30-60 minutes in the absence of a solid catalyst; or at 180-240 °C for 10-120 minutes, preferably 30-60 minutes, in the presence of a solid catalyst, thereby causing depolymerization of lignin in the black liquor; c) cooling the composition to a temperature below the boiling point of a solvent to be added in a subsequent step; d) acidifying the composition by adding one or more acidifying agents until a pH of 4-5 is reached; e) adding a solvent to the composition, in order to extract oil from the composition; f) separating the composition by phase separation in a first separation step into - an oil phase comprising solvent, oil, and organic acids, - a first water phase comprising water, salts, and non-depolymerized lignin solids, - a second water phase comprising water and salts; - an oil phase comprising solvent, oil, and organic acids, - a first water phase comprising water, salts, and non-depolymerized lignin solids, - a second water phase comprising water and salts; g) filtering the first phase to remove any particles; h) desalting the filtered oil phase by I) washing it by adding water and separating by phase separation in a second separation step into - an oil phase comprising oil and solvent, - a third water phase comprising salts; or II) adding adsorbent and/or absorbent material or ion exchange material, or combinations thereof; I) washing it by adding water and separating by phase separation in a second separation step into - an oil phase comprising oil and solvent, - a third water phase comprising salts; or - an oil phase comprising oil and solvent, - a third water phase comprising salts; or II) adding adsorbent and/or absorbent material or ion exchange material, or combinations thereof; i) evaporating the solvent comprised in the oil phase, thus obtaining a bio-oil.