Abstract: A continuous process for producing crystalline ammonium sulfate, said process comprising a start-up operation followed by a steady-state operation, wherein the start-up operation comprises: i) in a crystallizer, evaporating solvent from an approximately saturated ammonium sulfate solution; ii) replacing evaporated solvent with further approximately proximately saturated ammonium sulfate solution; iii) introducing to the crystallizer seed crystals of ammonium sulfate; iv) continuing to evaporate solvent, until a desired degree of supersaturation is reached; and v) recovering crystalline ammonium sulfate from ammonium sulfate solution in a recovery unit, and the steady-state operation comprises: vi) continuously feeding approximately saturated ammonium sulfate solution into the crystallizer and continuously withdrawing ammonium sulfate crystals from the crystallizer, such that the total combined volume of ammonium sulfate solution and ammonium sulfate crystals within the crystallizer remains constant; and vii)

Abstract: The present invention provides a continuous process for producing ammonium sulfate crystals, wherein said process comprises: i) feeding to a series of crystallization sections, which crystallization sections are heat integrated in series, a solution of ammonium sulfate; ii) crystallizing ammonium sulfate crystals from said solution of ammonium sulfate; iii) purging a fraction of the solution of ammonium sulfate from each of said crystallization sections; and iv) discharging ammonium sulfate crystals from each crystallization section, characterized in that: a fraction of said solution of ammonium sulfate is purged from at least one crystallization section to at least one other crystallization section; and an apparatus suitable for producing ammonium sulfate crystals.

Abstract: The present invention provides a continuous process for producing ammonium sulfate crystals, wherein said process comprises: (a) feeding to a first group of crystallization sections, which crystallization sections are heat integrated in series, a first aqueous ammonium sulfate solution that contains one or more impurities; (b) feeding to a second group of crystallization sections, which crystallization sections are heat integrated in series, a second aqueous ammonium sulfate solution that contains one or more impurities; (c) crystallizing ammonium sulfate crystals in each crystallization section respectively from each of said solutions of ammonium sulfate that contain one or more impurities; (d) purging a fraction of the ammonium sulfate solution that contains one or more impurities from each of said crystallization sections; and (e) discharging ammonium sulfate crystals from each crystallization section, characterized in that: (i) both the first group of crystallization sections and the second group of c

Abstract: The invention relates to a process for preparing a crystalline ammonium sulfate product, which process comprises: a) subjecting in a crystallizer a feed solution of ammonium sulfate to crystallization to form a first slurry of ammonium sulfate crystals; b) subjecting the first slurry of ammonium sulfate crystals to a first size classification to yield a first coarse ammonium sulfate crystal fraction and a first fine ammonium sulfate crystal fraction; c) recycling at least part of the first fine ammonium sulfate crystal fraction to the feed solution of ammonium sulfate; and d) recovering a crystalline ammonium sulfate product from the first coarse ammonium sulfate crystal fraction, characterized in that: e) a second size classification is carried out on a second slurry of ammonium sulfate crystals to yield a second coarse ammonium sulfate crystal fraction and a second fine ammonium sulfate crystal fraction.

Abstract: The present invention provides a continuous process for producing ammonium sulfate crystals, wherein said process comprises: i) feeding to a series of crystallization sections, which crystallization sections are heat integrated in series, a solution of ammonium sulfate; ii) crystallizing ammonium sulfate crystals from said solution of ammonium sulfate; iii) purging a fraction of the solution of ammonium sulfate from each of said crystallization sections;and iv) discharging ammonium sulfate crystals from each crystallization section, characterized in that: a fraction of said solution of ammonium sulfate is purged from at least one crystallization section to at least one other crystallization section; and an apparatus suitable for producing ammonium sulfate crystals.

Abstract: The present invention provides a continuous process for producing ammonium sulfate crystals, wherein said process comprises: (a) feeding to a first group of crystallization sections, which crystallization sections are heat integrated in series, a first aqueous ammonium sulfate solution that contains one or more impurities; (b) feeding to a second group of crystallization sections, which crystallization sections are heat integrated in series, a second aqueous ammonium sulfate solution that contains one or more impurities; (c) crystallizing ammonium sulfate crystals in each crystallization section respectively from each of said solutions of ammonium sulfate that contain one or more impurities; (d) purging a fraction of the ammonium sulfate solution that contains one or more impurities from each of said crystallization sections; and (e) discharging ammonium sulfate crystals from each crystallization section, characterized in that: (i) both the first group of crystallization sections and the second group of c

Abstract: A continuous process for producing crystal-line ammonium sulfate, said process comprising a start-up operation followed by a steady-state operation, wherein the start-up operation comprises: i) in a crystallizer, evaporating solvent from an approximately saturated ammonium sulfate solution; ii) replacing evaporated solvent with further approximately proximately saturated ammonium sulfate solution; iii) introducing to the crystallizer seed crystals of ammonium sulfate; iv) continuing to evaporate solvent, until a desired degree of supersaturation is reached; and v) recovering crystalline ammonium sulfate from ammonium sulfate solution in a recovery unit, and the steady-state operation comprises: vi) continuously feeding approximately saturated ammonium sulfate solution into the crystallizer and continuously withdrawing ammonium sulfate crystals from the crystallizer, such that the total combined volume of ammonium sulfate solution and ammonium sulfate crystals within the crystallizer remains constant; and vii)

Abstract: The invention relates to a process for preparing a crystalline ammonium sulfate product, which process comprises: a) subjecting in a crystallizer a feed solution of ammonium sulfate to crystallization to form a first slurry of ammonium sulfate crystals; b) subjecting the first slurry of ammonium sulfate crystals to a first size classification to yield a first coarse ammonium sulfate crystal fraction and a first fine ammonium sulfate crystal fraction; c) recycling at least part of the first fine ammonium sulfate crystal fraction to the feed solution of ammonium sulfate; and d) recovering a crystalline ammonium sulfate product from the first coarse ammonium sulfate crystal fraction, characterized in that: e) a second size classification is carried out on a second slurry of ammonium sulfate crystals to yield a second coarse ammonium sulfate crystal fraction and a second fine ammonium sulfate crystal fraction.

Abstract: The invention relates to a continuous process for preparing large crystal products of a crystalline product in a fluid bed crystallizer, said fluid bed crystallizer comprising a crystallization vessel and means for mechanically impacting of crystals; and connected to the crystallization vessel (i) a feed line; (ii) an external circulation circuit comprising means for determining properties of the slurry in the external circulation circuit and a heat exchanger; and (iii) a product withdrawal line, wherein—for any specific crystalline product and at any flow rate chosen in the external circulation circuit—the weight percentage of crystals of the crystalline product in the slurry in the external circulation circuit, ECCWPC, is controlled by said means for determining properties of the slurry within a specified and predetermined narrow range having a maximum and minimum value not more apart than at most 25% by weight and falling within the range of from 1 to 50% by weight.

Abstract: The invention relates to a continuous process for preparing large crystal products of a crystalline product in a fluid bed crystallizer, said fluid bed crystallizer comprising a crystallization vessel and means for mechanically impacting of crystals; and connected to the crystallization vessel (i) a feed line; (ii) an external circulation circuit comprising means for determining properties of the slurry in the external circulation circuit and a heat exchanger; and (iii) a product withdrawal line, wherein—for any specific crystalline product and at any flow rate chosen in the external circulation circuit—the weight percentage of crystals of the crystalline product in the slurry in the external circulation circuit, ECCWPC, is controlled by said means for determining properties of the slurry within a specified and predetermined narrow range having a maximum and minimum value not more apart than at most 25% by weight and falling within the range of from 1 to 50% by weight.