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Liquid Lignin Company, LLC

Westvaco Corporation

Michael A Lake

John C Blackburn

J George Hayden

John H Thomas

Philip A Robinson

Gary B Womack

Don P Duncan

Craig R McIntyre

This invention provides improvements to processes for making granular lignin from black liquor. One of the improvements is that the use of a pre-carbonation column reduces the COflow into the sparger of a carbonation column. The pre-carbonation column is used to reduce the pH of the black liquor to about 12. Another improvement is that it has been found that coalescing droplets into a bulk liquid-lignin phase can be enhanced by placing the exit of the carbonation column at or slightly beneath carbonated black liquor/liquid-lignin interface. It has also been found that operating the carbonation settler at a low pressure and pumping the liquid-lignin from the carbonation settler to the acidification reactor operating at a higher pressure allows recycling the vent gas from the acidification reactor to the pre-carbonation column. The invention also provides for a vent gas absorber.

Process for treating lignin

There is provided a process for recovery of lignin from black liquor that contains either soluble or dispersed lignin, generating a 'liquid-lignin' at high yield. Lignin at elevated pH is precipitated by reducing the pH of the black liquor stream with carbon dioxide, at elevated temperature and pressure, creating two bulk fluid phases: a dense liquid-lignin phase and a light lignin-depleted phase. The dense liquid-lignin phase is separated and washed with a strong acid to displace metal cations from the lignin, creating a low-salt, randomly shaped lignin. If needed, especially for lignin recovered from kraft papermaking black-liquor streams, an oxidation step is included to eliminate negative odor for high value green chemistry applications.

Lignin product and process for making same

A process for recovery of lignin from black liquor that contains either soluble or dispersed lignin by generating a 'liquid lignin' at high yield is disclosed. Soluble lignin at a high pH is precipitated by reducing the pH of the black liquor stream by countercurrent reaction with carbon dioxide, at elevated temperature and pressure, creating a dense liquid-lignin phase and a light lignin-depleted phase. The dense lignin-rich phase is separated and washed countercurrently with a non-sulfur containing acid, such as acetic acid or formic acid, to displace metal cations from the lignin, creating a low-salt lignin, which is then formed into a low-dust, high-bulk density lignin fuel pellet. If desired, an oxidation step may be used to eliminate odor for lignins having high value green chemistry applications.

Treated wood, wood preservative compositions, and methods for treating wood generally include applying to the wood a wood preservative composition comprising a boron containing compound and a pH-reduced black liquor comprising soluble lignin, wherein the boron-containing compound is soluble in the pH-reduced black liquor and wherein the pH-reduced black liquor is derived from a carbonation process or an acid addition process of black liquor having phase-separated solid lignin and/or dense liquid lignin removed therefrom, and drying the wood.

Wood preservatives and methods for treating wood

There is provided a process for recovery of lignin from a black liquor that contains either soluble or dispersed lignin, generating a 'liquid lignin' at high yield. Soluble lignin at elevated pH is precipitated by reducing the pH of the black liquor stream by countercurrent reaction with carbon dioxide, at elevated temperature and pressure, creating two bulk fluid phases: a heavy lignin-rich phase and a light lignin-depleted phase. The heavy lignin-rich phase is separated and washed countercurrently with a strong acid to displace metal cations from the lignin, creating a low-salt lignin, which is then formed into a low-dust high-bulk-density lignin fuel pellet. If needed, especially for lignin recovered from kraft papermaking black-liquor streams, an oxidation step is included to eliminate negative odor for high-value green-chemistry applications.

Process for recovering lignin

A process for recovery of lignin from black liquor that contains either soluble or dispersed lignin by generating a 'liquid lignin' at high yield is disclosed. Soluble lignin at a high pH is precipitated by reducing the pH of the black liquor stream by countercurrent reaction with carbon dioxide, at elevated temperature and pressure, creating a heavy lignin-rich phase and a light lignin-depleted phase. The heavy lignin-rich phase is separated and washed countercurrently with a non-sulfur containing acid, such as acetic acid, to displace metal cations from the lignin, creating a low-salt lignin, which is then formed into a low-dust, high-bulk density lignin fuel pellet. If desired, an oxidation step may be used to eliminate odor for lignins having high value green chemistry applications.

Phosphinic acid (also called hypophosphorous acid), when used in very small quantities, is disclosed to act as a catalyst to accelerate the reaction of rosin with an unsaturated dibasic acid to form a modified rosin for subsequent esterification with a polyhydric alcohol. According to the process of the invention, a rosin is reacted with an unsaturated dibasic acid such as maleic anhydride or fumaric acid in the presence of phosphinic acid at a temperature of from about 180.degree. C. to about 220.degree. C. When the modified rosin is subsequently esterified, the rosin ester exhibits improved color, softening point, and viscosity in a specified solution.

Growing community of inventors

Mt. Pleasant, SC, United States of America

Michael A Lake