Abstract: Disclosed is a method for linkage recovery of an organic acid in an aqueous organic acid solution. The method comprises: mixing a solution with an organic acid concentration lower than 20 wt % with a specific extractant and then subjecting same to counter-current extraction so as to obtain an extract phase and a raffinate phase; and subjecting the extract phase together with a solution with an acid concentration higher than 70 wt % to an azeotropic rectification so as to recover an organic acid. When the concentration of the aqueous organic acid solution is 20 wt %-70 wt %, the aqueous organic acid solution is extracted and concentrated to make the concentration of the aqueous organic acid solution higher than 70 wt %.

Abstract: The present document discloses a method for purifying lignin. The method comprises steps of solvent dissolution, ultrasonic vibration, centrifugal filtration, stirring in water at a constant temperature, and membrane filtration and drying. In the present application, lignin extracted from a plant fiber raw material using an organic solvent is added to a specific solvent, and is purified by sequentially performing the steps of ultrasonic vibration, centrifugal filtration, stirring in water at a constant temperature, and membrane filtration and drying. Any of the steps cannot be omitted and the sequence thereof cannot be reversed. The steps are efficiently coordinated to achieve a synergistic effect, so as to remove impurities in lignin, and significantly improve the purity of the lignin while maintaining a high purification yield. The invention has broad application prospects and high market value.

Abstract: Provided is a method for preparing furfural. The method comprises: mixing a plant raw material and an acid containing a —SO3H functional group for pre-treating, then mixing same with an organic acid, cooking same, and then subjecting same to solid-liquid separation, so as to obtain a hemicellulose sugar solution; introducing the resulting hemicellulose sugar solution from the upper part of a reaction kettle, and at the same time, introducing an acetic acid steam from the lower part of the reaction kettle, such that the sugar solution and the acetic acid steam come into contact in a counter-current manner and react so as to form a furfural steam; after the reaction is completed, discharging the furfural steam from the upper part of the reaction kettle; and cooling same so as to obtain a solution containing furfural.

Abstract: Provided is a method for preparing furfural. The method comprises: mixing a plant raw material and an acid containing a —SO3H functional group for pre-treating, then mixing same with an organic acid, cooking same, and then subjecting same to solid-liquid separation, so as to obtain a hemicellulose sugar solution; introducing the resulting hemicellulose sugar solution from the upper part of a reaction kettle, and at the same time, introducing an acetic acid steam from the lower part of the reaction kettle, such that the sugar solution and the acetic acid steam come into contact in a counter-current manner and react so as to form a furfural steam; after the reaction is completed, discharging the furfural steam from the upper part of the reaction kettle; and cooling same so as to obtain a solution containing furfural.

Abstract: The present document discloses a method for purifying lignin. The method comprises steps of solvent dissolution, ultrasonic vibration, centrifugal filtration, stirring in water at a constant temperature, and membrane filtration and drying. In the present application, lignin extracted from a plant fiber raw material using an organic solvent is added to a specific solvent, and is purified by sequentially performing the steps of ultrasonic vibration, centrifugal filtration, stirring in water at a constant temperature, and membrane filtration and drying. Any of the steps cannot be omitted and the sequence thereof cannot be reversed. The steps are efficiently coordinated to achieve a synergistic effect, so as to remove impurities in lignin, and significantly improve the purity of the lignin while maintaining a high purification yield. The invention has broad application prospects and high market value.

Abstract: Disclosed is a method for linkage recovery of an organic acid in an aqueous organic acid solution. The method comprises: mixing a solution with an organic acid concentration lower than 20 wt % with a specific extractant and then subjecting same to counter-current extraction so as to obtain an extract phase and a raffinate phase; and subjecting the extract phase together with a solution with an acid concentration higher than 70 wt % to an azeotropic rectification so as to recover an organic acid. When the concentration of the aqueous organic acid solution is 20 wt %-70 wt %, the aqueous organic acid solution is extracted and concentrated to make the concentration of the aqueous organic acid solution higher than 70 wt %.