Black liquor viscosity control
AssigneeThor Technology Corporation
InventorsJohn N. Harbinson, David Todd R. Ellenor
Life of this patent
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Abstract
Black liquor is subjected to high shear to cause a breakdown of macromolecules contained therein and provide a reduction in viscosity, thereby improving the processability of the black liquor and enabling the solids content to be increased.
Claims25
A process of controlling the viscosity of black liquor from a pulping operation, which comprises subjecting the black liquor to physical conditions to effect shearing of black liquor macromolecules to decrease their molecular size and produce a decrease in viscosity of the black liquor of at least about 5%.
A process of controlling the viscosity of black liquor from a pulping operation, which comprises subjecting the black liquor to physical conditions by passing the black liquor through a gap between a rotor and stator of a high shear mixer operating at a peripheral velocity of rotor of at least about 10 m/s with a gap between the rotor and stator at less than about 1 mm to effect shearing of black liquor macromolecules to decrease their molecular size and produce a decrease in viscosity of the black liquor of at least about 5%.
A process of decreasing the viscosity of black liquor from a pulping operation, which comprises:
- providing a concentrated black liquor from the pulping of hardwood or softwood pulps having a solids content of about 40 to about 85 wt%,
- heating said concentrated black liquor to a temperature of about 75.degree. to about 300.degree. C.,
- passing said concentrated black liquor through a high shear zone wherein macromolecules in said concentrated black liquor are subjected to physical conditions of high shear to effect, in a gap between a rotor and a stator of a high shear mixer operating at a peripheral velocity of rotor of at least about 10 m/s with the gap between rotor and stator of less than about 1 mm, molecular size reduction and achieve a decrease in viscosity of said concentrated black liquor of at least about 5%, and
- recovering the treated black liquor having decreased viscosity.
A process for decreasing the viscosity of black liquor from a pulping operation, which comprises processing the black liquor in equipment primarily intended to shear molecules for a time and at a temperature sufficient to effect a decrease in viscosity.
A process for decreasing the viscosity of black liquor from a pulping operation, which comprises processing the black liquor in equipment primarily intended to shear molecules and comprises a high shear mixer comprising a rotor and a stator by passing the black liquor through a gap between the rotor and stator wherein said high speed mixer is operated at a peripheral rotor velocity of at least about 10 m/s with a gap between rotor and stator of less than about 1 mm.
Dependencies are inferred from the claim text.