Delignification of non-woody biomass
AssigneeXylan Corporation
InventorGeorge J. Tyson
Life of this patent
Estimating the term…
Abstract
A non-woody biomass is delignified through extrusion technology, utilizing hydrogen peroxide and an alkali agent, to break down complex biomass materials. The process is useful in forming a highly absorbent fiber material for use as a dietary fiber or an absorbent fiber. Alternatively, the process is useful for preparing dietary feeds for ruminant animals, as well as produce a broad range of alcohols or polymers from the non-woody lignocellulosic substrate.
Claims34
A process for continuously treating a non-woody lignocellulosic substrate consisting of organic plant material having no more than about 20% lignin content, the process consisting essentially of:
- (a) reacting the substrate in a reaction medium including an aqueous solution of a strong alkali at a pH in the range of about 10.5 and 12.5;
- (b) reacting a chelating agent with the substrate the chelating agent being in an amount and for a time effective to chelate any metal ions in the solution;
- (c) continuously feeding the product of step b) to an aqueous solution in a pressurized extruder reactor and reacting the substrate in an oxygen atmosphere at a temperature between about 150.degree. and 315.degree. F. and at a pressure between about 250 and 450 psi, and in the presence of hydrogen peroxide for a period of time effective to delignify the substrate wherein the hydrogen peroxide is added to the extruder at a rate of between about 20 and 40 pounds of hydrogen peroxide per ton of substrate.
A process for continuously preparing a nearly white, non-woody, delignified dietary fiber suitable for food grade consumption, wherein the fiber contains at leat 80% cellulose, the process consisting essentially of the following steps of sequence:
- (a) reacting an organic non-woody lignocellulosic substrate having no more than about 20% lignin in a reaction medium including an aqueous solution of a strong alkali at a pH in the range of about 10.5 and 11.8;
- (b) reacting a chelating agent with the substrate, the chelating agent being in an amount and for a time effective to chelate any metal ions in the solution;
- (c) continuously feeding the substrate of step (b) to a pressurized extruder reactor and reacting the substrate in an oxygen atmosphere at a temperature between about 150.degree. and 315.degree. F. and at a pressure between about 250 and 450 psi, and in the presence of hydrogen peroxide for a period of time effective to delignify the substrate wherein the hydrogen peroxide is added to the extruder at a rate of between about 20 and 40 lbs. of hydrogen peroxide per ton of substrate;
- (d) washing the substrate in an aqueous wash solution to remove the hemicellulose and lignin from the substrate;
- (e) washing the substrate in an acid bath including an aqueous acid bath solution having a pH between about 0.5 and 3.0;
- (f) washing the substrate in an aqueous pH correction solution, wherein a buffering agent is added to the aqueous pH correction solution to adjust the pH to between about 6.5 and 7.0;
- (g) reducing the moisture content of the substrate to a moisture level between about 55% and 65%;
- (h) fluffing the substrate;
- and
- (i) drying the substrate at a temperature no greater than about 180.degree. F.
A process for continuously preparing a ruminant feed source consisting essentially of the following steps in sequence:
- (a) reacting a non-woody lignocellulosic substrate consisting of organic plant material having no more than 20% lignin in a reaction medium including an aqueous solution of a strong alkali at a pH in the range of about 10.5 and 12.5;
- (b) reacting a chelating agent with the substrate, the chelating agent being in an amount effective to chelate any metal ions in the solution;
- (c) continuously feeding the substrate of step b) to a pressurized extruder reactor and reacting the substrate in an oxygen atmosphere at a temperature between about 150.degree. and 315.degree. F. and at a pressure between about 250 and 450 psi, and in the presence of hydrogen peroxide for a period of time effective to delignify the substrate wherein the hydrogen peroxide is added to the extruder at a rate of between about 20 and 40 lbs.of hydrogen peroxide per ton of substrate;
- and
- (d) cooling the substrate.
A process for continuously preparing a highly absorbant fiber source consisting essentially of the following steps in sequence:
- (a) reacting a non-woody lignocellulosic substrate consisting of organic plant material having no more than about 20% lignin content in a reaction medium includng an aqueous solution of a strong alkali at a pH in the range of about 10.5 and 12.5;
- (b) reacting a chelating agent with the substrate, the chelating agent being in an amount and for a time effective to chelate any metal ions in the solution;
- (c) contnnuously feeding the substrate of step b) to a pressurized extruder reactor in an oxygen atmosphere at a temperature between about 150.degree. and 315.degree. F. and at a pressure between about 250 and 450 psi, and in the presence of hydrogen peroxide for a period of time effective to delignify the substrate wherein the hydrogen peroxide is added to the extruder at a rate of between about 20 and 40 lbs. of hydrogen peroxide per ton of substrate;
- (d) washing the substrate in an aqueous wash solution to remove the hemicellulose and lignin from the substrate;
- (e) washing the substrate in an acid bath including an aqueous acid bath solution having a pH between about 0.5 and 3.0;
- (f) washing the substrate in an aqueous pH correction solution, wherein a buffering agent is added to the aqueous pH correction solution to adjust the pH to between about 6.5 and 7.0;
- (g) reducing the moisture content of the substrate to a moisture level between about 55% and 65%;
- (h) fluffing the substrate;
- and
- (i) drying the substrate at a temperature no greater than about 180.degree. F.
Dependencies are inferred from the claim text.