A BATCH PROCESS FOR PRODUCING BIO-OIL FROM SPENT BLACK LIQUOR

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 -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 (AA1);b) reacting the black liquor composition in a reactor (R) 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 (AA2) until a pH of 4-5 is reached;e) adding a solvent (S) to the composition， in order to extract oil from the composition;f) separating the composition by phase separation in a first separation step (S1) intoan oil phase (A) comprising solvent， oil， and organic acids; a first water phase (B) comprising water， salts， and non-depolymerized lignin solids; a second water phase (C1) comprising water and salts;g) filtering (F2) the first phase (A) to remove any particles;h) desalting the filtered oil phase (A) byi) washing it by adding water and separating by phase separation in a second separation step (S2) into an oil phase (D) comprising oil and solvent， and a third water phase (C2) comprising salts; orii) adding adsorbent and/or absorbent material or ion exchange material， or combinations thereof;i) evaporating (E2) the solvent comprised in the oil phase (D)， thus obtaining a bio-oil. 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 -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 (AA1);b) reacting the black liquor composition in a reactor (R) 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 (AA2) until a pH of 4-5 is reached;e) adding a solvent (S) to the composition， in order to extract oil from the composition;f) separating the composition by phase separation in a first separation step (S1) intoan oil phase (A) comprising solvent， oil， and organic acids; a first water phase (B) comprising water， salts， and non-depolymerized lignin solids; a second water phase (C1) comprising water and salts;g) filtering (F2) the first phase (A) to remove any particles;h) desalting the filtered oil phase (A) byi) washing it by adding water and separating by phase separation in a second separation step (S2) into an oil phase (D) comprising oil and solvent， and a third water phase (C2) comprising salts; orii) adding adsorbent and/or absorbent material or ion exchange material， or combinations thereof;i) evaporating (E2) the solvent comprised in the oil phase (D)， thus obtaining a bio-oil.