WO2023137154A1

WO2023137154A1 - Process for treating land-based plant and marine-based biomasses

Info

Publication number: WO2023137154A1
Application number: PCT/US2023/010765
Authority: WO
Inventors: Melvin Mitchell; John E. Cahill
Original assignee: Greenkey Llc
Priority date: 2022-01-14
Filing date: 2023-01-13
Publication date: 2023-07-20

Abstract

The present invention provides a process for treating a biomass. The biomass may be from land-based plants or from marine-based plants to separate components such as cellulose, hemicellulose and lignin from the biomass. The process may include reducing the size of the biomass to provide the biomass in a fiber form and a suitable size for processing. The biomass fibers are then subjected to an apparatus to mechanically internally fibrillate the fibers often over a short time frame of less than about 10 seconds. The internal fibrillation alter the cell walls of the fibers to facilitate the separation of the biomass components. The fibrillated biomass fibers are then subjected to a solution comprising a basic composition and an oxidation agent to pulp the fibers. The pulped fibers may substantially be cellulose and are separated from the basic/oxidation agent solution. The pulped fibers may be formed into paper grade pulp for making a paper article of manufacture.

Description

PROCESS FOR TREATING LAND-BASED PLANT AND MARINE-BASED BIOMASSES

RELATED APPLICATION

[0001] The present application claims priority to Provisional Applications 63/299,465 filed January 14, 2022 and 63/341 ,040 filed May 12, 2022, the disclosure of which are herein incorporated in their entireties.

FIELD OF THE INVENTION

[0002] The present invention related to a process for treating a biomass, and particularly a process for separating components like cellulose from a land-based plant or marine-based biomass.

BACKGROUND

[0003] Biomasses may be the major feedstock to the pulp and paper industry. Exemplary biomasses include wood, wood residues, plants such as com, switchgrass, sugar cane and bamboo, agricultural waste, municipal solid waste, seaweed, and the like.

[0004] Historically land-based biomasses like wood were broken down into its cellulose, hemicellulose and lignin constituents using a Kraft pulping process. The Kraft pulping process typically includes treating wood, namely wood chips, with a hot reaction mixture of water, sodium hydroxide and sodium sulfide. The hot mixture breaks the bonds of the wood to form a pulp (cellulose) which may be converted to paper. This process tends to be slow, there is a noxious sulfur odor caused by the reaction mixture, and the process results in substantial and potentially hazardous liquid waste.

[0005] Moreover, if wood is used as the biomass, yields are often only 50 percent thus increasing demand for wood. Mechanical processes have yields but such comes with the limitation that lignin is still present. Thus, mechanical pulp is often bleached with sodium hydroxide or sodium dithionite with the downstream consequence of higher water treatment expense. [0006] Thus, there is a need for a sustainable process that is less energy intensive (e.g., does not require significant heat), reduces the amount and types of harsh chemicals used, reduces processing times, and reduces the amount and hazard level of the liquid waste of the process. Moreover, there is a need for a process that may be used with more sustainable sources of cellulose than using hardwood and softwood trees, as the source.

SUMMARY

[0007] It should be appreciated that this Summary is provided to introduce a selection of concepts in a simplified form, the concepts being further described below in the Details Description. This Summary is not intended to identify key features or essential features of this disclosure, nor is it intended to limit the scope of the invention.

[0008] The present invention provides a process for treating a biomass. The biomass may be from land-based plants (e.g., hemp) or from marine-based biomasses (e.g., seaweed) to separate components such as cellulose, hemicellulose and lignin from the biomass. The process may include reducing the size of the biomass to provide the biomass in a fiber form and a suitable size for processing. The biomass fibers are then subjected to an apparatus to mechanically internally fibrillate the fibers often over a short time frame of less than about 10 seconds. The internal fibrillation alters the cell walls of the fibers to facilitate the separation of the biomass components. The fibrillated biomass fibers are then subjected to a solution comprising a basic composition (e.g., sodium hydroxide) and an oxidation agent (e.g., hydrogen peroxide) to pulp the fibers. The chemical treatment are conducted at temperatures of less than 95°C and often at ambient temperature (24°C to 26°C). The pulped fibers may substantially be cellulose and are separated from the basic/oxidation agent solution along with an extract of the biomass. The cellulose pulped fibers may be dried and formed into paper grade pulp.

[0009] In another embodiment, the paper grade pulp may be combined with a starch, optionally a biomass extract and water to form a pulp slurry for forming paper articles of manufacture [0010] In another embodiment, the paper article of manufacture be formed from the pulp and pulp slurry may be coated with the biomass extract separated from the pulped fibers.

[0011] In an alternate embodiment, the pulped fibers may again be subjected to the mechanical internal fibrillation, a so-called “second pass” to further facilitate separation of the biomass components. These second pass fibers may then be subjected to the basic/oxidation agent solution again to further pulp the fibers followed by separating the fibers from the solution. These pulped fibers from the second pass may be formed into dissolving grade pulp, namely pulp having an alpha cellulose content of greater than about 90 percent.

DETAILED DESCRIPTION

[0012] The foregoing and other aspects of the present invention will now be described in more detail with respect to the description and methodologies provided herein. It should be appreciated that the invention can be embodied in different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. [0013] The terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used in the description of the embodiments of the invention and the appended claims, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. Also, as used herein, "and/or" refers to and encompasses any and all possible combinations of one or more of the associated listed items.

[0014] The term "about," as used herein when referring to a measurable value such as an amount of a compound, dose, time, temperature, and the like, is meant to encompass variations of 20%, 10%, 5%, 1%, 0.5%, or even 0.1% of the specified amount. Unless otherwise defined, all terms, including technical and scientific terms used in the description, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. [0015] As used herein, the terms "comprise," "comprises," "comprising," "include," "includes" and "including" specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.

[0016] As used herein, the term "consists essentially of" (and grammatical variants thereof), as applied to the compositions and methods of the present invention, means that the compositions/methods may contain additional components so long as the additional components do not materially alter the composition/method. The term "materially alter," as applied to a composition/method, refers to an increase or decrease in the effectiveness of the composition/method of at least about 20% or more.

[0017] All patents, patent applications and publications referred to herein are incorporated by reference in their entirety. In case of a conflict in terminology, the present specification is controlling.

[0018] The term land-based plant biomass” includes lignocellulosic materials, and may be wood (both hardwood and softwood), particle board, forestry wastes, sawdust, wood chips, grasses, switchgrass, miscanthus, cord grass, cotton gin mote, reed canary grass, grain residues, rice hulls, oat hulls, pea hulls, wheat chaff and hulls, barley hulls, peanut hulls, cotton linters, silage, canola straw, wheat straw, barley straw, oat straw, rice straw, jute, hemp, flax, kudzu, bamboo, sisal, abaca, sorghum, com cobs, corn stover, soybean stover, com fiber, alfalfa, hay, tomato leaves, coconut hair, sugar bagasse and sugar processing residues, beet pulp, agave bagasse, and agricultural and industrial wastes or mixtures or blends of any of these.

[0019] Plant biomass comprises three major components, namely hemicellulose, cellulose, lipid, and lignin. Hemicellulose is a polysaccharide comprising the pentose and hexose sugars xylon, glucuronoxylon, arabinoxylon, glucomannon, and xyloglucan. The sugars are highly substituted with acetic acid, and because of its branched structure, hemicellulose is amorphous. Hemicellulose may be easily cleaved via hydrolysis. In contrast, cellulose (alpha cellulose) is a polysaccharide of glucose sugars bonded together by l3>-glycosidic linkages to form lengthy linear chains. Hydrogen bonding can occur between cellulose chains and results in a rigid crystalline structure which is resistant to cleavage. Lignin is a polymer of phenolic molecules and is hydrophobic. It provides structural integrity to plants, i.e. , it is the glue that maintains the plant intact. The biomass may include lesser components such as sugars, lipids, proteins, ash, pectins and cutin, and other materials obtained from the leaves, stems, flowers, buds, roots, tubers, seeds, nuts, fruit, and the like of a plant.

[0020] Marine-based biomasses may include seaweed and algae such as Sargassum seaweed. It is understood that literally seaweed and algae are not plants because they often lack true stems, roots, leaves and vascular tissue. Seaweed and algae do have special parts that undergo photosynthesis. Seaweed and algae typically comprise cellulose and hemicellulose and often are substantially devoid of lignin.

[0021] The present invention provides a process for treating a biomass to separate components such as cellulose, hemicellulose and/or lignin from the biomass. The process may include reducing the size of the biomass to provide the biomass in a fiber form and a suitable size for processing. By providing the biomass in fiber form, the fibers are initially opened up by chopping, cutting, fraying or attrition. A refiner or disk mill may be used.

[0022] The biomass fibers are then subjected to an apparatus to mechanically internally fibrillate the fibers often over a short time frame of less than about 10 seconds. The phrase “mechanically internally fibrillate” is intended to mean a process or treatment in which the bonds between the tiny fibrils and microfibrils of a plant cell walls are destroyed and allows penetration of water into the space between the fibrils to fluidize or make flowable the biomass fibers. Internal fibrillation allows the fibers to be able to form bonds during the pulping process while maintaining strength.

[0023] In one embodiment, the fibrillation may be accomplished using a 1 .5# Voith Valley Beater available from Voith Group, Heidenheim, Germany or if biomass already dried, using a screw press. A dried biomass may also be rehydrated and pressed through the equipment again.

[0024] In another embodiment, the biomass fibers may be mechanically internally fibrillated over a short time frame of less than 10 seconds. Such an apparatus is described, for example, in WO 93/25584, WO 94/03497, and U.S. Patent No. 4,016, 353, the disclosures of which are incorporated by reference in their entireties and are available from Kadant Black Clawson, Lebanon, Ohio.

[0025] The fibrillated biomass fibers are then subjected to an aqueous solution comprising a basic composition (e.g., sodium hydroxide) and an oxidation agent (e.g., hydrogen peroxide) to pulp the fibers. This step is performed at temperatures less than 95°C and often at ambient temperature (24°C to 26°C). It is noted that mild heat (e.g., 50°C to 70°C) may be added to facilitate reaction of the fibers with the basic composition. An aqueous solution is one in which the basic or oxidation agent is blended or mixed with water. “Water” is intended to include deionized water, distilled water, mineral water, tap water, well water, river water and spring water, and mixtures thereof. Inasmuch as fibrillation increases the surface area of the fibers, this makes the fibers more susceptible to reaction with the basic/oxidation agent solutions. The pulped fibers may substantially be cellulose and are separated from the basic/oxidation agent solution along with an extract of the biomass. The cellulose pulped fibers may be formed into paper grade pulp.

[0026] The pulp may be formed into a pulp slurry for papermaking and paper conversion, namely for forming a paper article of manufacture. In one embodiment, the pulp slurry comprises pulp, water, optionally starch and optionally a biomass extract such as separated from the pulped fibers. Exemplary starch sources include corn, potato, waxy maize, wheat, and tapioca. The starch may be cationic, anionic, or amphoteric, and often have high levels of amylopectin. The starch may include a hydrolysis aid (e.g., hydrogen peroxide).

[0027] In one embodiment, the biomass extract may be applied to the paper article of manufacture as a coating to strengthen the article of manufacture made from the pulp. Such extracts may also provide barrier properties related to the transport of moisture and gases. The extracts may be blended with biopolymers to improve performance. The coating may be accomplished by extrusion coating, spray coating, curtain coating, size press coating, bar coating and dip coating.

[0028] In an alternate embodiment, the process may include repeating the mechanical internal fibrillation step to further facilitate separation of biomass components and to provide dissolving grade pulp, namely pulp having an alpha cellulose content of greater than about 90 percent.

[0029] The basic solution may be any aqueous solution, alkaline metal hydroxide, carbonate, phosphate, or borate. In one embodiment, the alkaline metal hydroxide is sodium hydroxide, sodium carbonate or sodium borate. Mixtures or blends of the hydroxides, carbonates, phosphates, and borates may be used. The pH may be from about 7.0 to about 13.0 and sometimes may be from about 9.0 to about 12.0.

[0030] Suitable oxidation agents include hydrogen peroxide. The oxidation agent facilitates cleavage of the lignin ether bond. Other oxidation agents may include sodium peroxide, calcium peroxide, magnesium peroxide and sodium percarbonate.

[0031] A catalyst may be included with the basic/oxidation agent solution. In one embodiment, the catalyst may be a transition metal catalyst such as iron, manganese, and cobalt.

[0032] The pulp may be separated, isolated, or purified from the aqueous solution by centrifugation or by membrane separation or a combination thereof to provide the paper grade pulp separate from an extract of the biomass.

[0033] The isolated pulp from the first pass may be utilized to make a wide variety of paper articles of manufacture including coated and uncoated paper-based products, for example tissue, board, printing, and specialty papers. The isolated dissolving grade pulp from the second pass may be used to make various textiles and used in the manufacture of viscose (rayon). End products may include clothing, non-wovens (e.g. for filters and hygiene products), and cellophane.

[0034] The pulp may be blended with virgin pulp or with pulp from a wide variety of biomasses using the present invention. For example, pulp based on a marinebased biomass may be blended with virgin pulp or with pulp from a land-based plant biomass treated according to the present invention. Often the blend between virgin pulp and the biomass pulp is between 50 to 95 percent virgin pulp to 5 to 50 percent biomass pulp, and often the amount of the virgin pulp is greater than 80 percent of the blend.

EXAMPLES

[0035] The invention now will be described in additional detail, by way of example only with reference to the following examples.

FILM FORMING OF BIOMASS EXTRACT

[0036] Various biomasses were treated and separated into a fibrous pulp and a liquid extract. The liquid extract may be applied to a web and formed into a film. The selected biomass is treated by chopping and fibril lating using a 1 .5# Voith Valley Beater. The biomass is then screen washed and pressed using a Samson SB0850 screw press. The fibrillated biomass is then mixed with sodium hydroxide and water and placed in an oven at 140°F for 30 minutes. Hydrogen peroxide is added to cover the treated biomass. The biomass is then screen pressed and pressed using an Omega 8006 screw press. The pulped biomass and biomass extract are collected in separate containers. The biomass extract can be coated onto a web and dried into a film to demonstrate its ability as a coating.

[0037] The results for various biomasses are as follows:

BIOMASS EXTRACTED BIOMASS FILM FORMING

CAPABILITY

Wheat/Barley Straw Yes Yes

Sargassum Seaweed Yes Yes

Wheat Hulls Yes Yes

Soybean Hulls Yes Yes

Cotton Gin Mote Yes Yes

Hemp Yes Yes

Sugar Bagasse Yes Yes

Cotton Linters Yes Yes

Agave Yes Yes

HEMP EXAMPLE

[0038] Hemp stalks were chopped and refined using 1 .5# Voith Valley Beater. The chopped hemp was fibrillated for 10 minutes using a cutting weight of 5.2 kilograms and an additional 10 minutes using a hydration weight of 0.2 kilograms. The hemp was pulp screen washed and pressed using a Samson Model SB0850 screw press. 180 grams of pressed hemp was mixed in an insulated stainless vessel with 32 grams of NaOH and 800 ml water and placed in a 140°F heated oven for 30 minutes. The kettle was removed from the oven and 30 ml of HOOH was added to the kettle and covered for one hour. An additional 20 ml of HOOH was added to the kettle and covered for an additional hour. The treated hemp pulp was removed from the kettle and screen washed. The screen washed pulp was pressed using an Omega Model 8006 screw press. The hemp pulp and hemp liquid extract were collected in separate containers.

[0039] The hemp pulp is formed into a hand sheet and weighed. The solids level of the hemp extract are measured using Mettler Toledo LJ16 Moisture Analyzer and the extract solids level adjusted to 4 to 5 percent. A uniform wet coating is applied using an Acculab Drawdown Machine using a #36 drawdown rod. Two drawdowns on each side and another in each direction (top to bottom) and (bottom to top) are conducted. The sheet is then air dried for 24 hours.

[0040] Dried Sargassum seaweed was screen washed twice and 180 grams of Sargassum was mixed in an insulated stainless vessel with 16 grams of NaOH and 800 ml water and placed in a 140°F heated oven for 30 minutes. The kettle was removed and 20 ml of HOOH was added to the kettle and covered for one hour. An additional 20 ml of HOOH was added to the kettle and covered for an additional hour. The Sargassum pulp was removed from the kettle and screen washed. The screen washed Sargassum pulp was pressed using an Omega Model 8006 screw press. Sargassum pulp and Sargassum liquid extract were collected in separate containers during the pressing process.

[0041] The hemp extract and Sargassum extract are mixed with the hemp pulp, water, and Avebe Solvitose N starch to form a pulp slurry and a hand sheet formed. The hemp pulp hand sheet is then coated with either the hemp extract or the Sargassum extract. The results are in Table 1 .

Table 1

Coating Basis Tear Tensile Burst

Weight (gf) (g/15mm) (psig)

Hemp I Starch/Handsheet 123.9 52.5 3134 6.7

Hemp/Starch/Hemp Extract Handsheet with 122.5 70 4631 14.6

12.5% Hemp extract overcoat

Hemp/Starch/Hemp Extract/Sargassum Extract 123.4 67.5 5407 17.3

Handsheet with 12.5% Sargassum extract overcoat

Hemp/Starch/Hemp Extract/12.5% Sargassum 125.8 72.5 5789 20.5 extract with 12.5% Hemp extract overcoat

The examples in Table 1 demonstrate that a paper article of manufacture may be produced with or without a coating of the biomass extract.

[0042] Although the present approach has been illustrated and described herein with reference to preferred embodiments and specific examples thereof, it will be readily apparent to those of ordinary skill in the art that other embodiments and examples may perform similar functions and/or achieve like results. All such equivalent embodiments and examples are within the spirit and scope of the present approach.

Claims

THAT WHICH IS CLAIMED IS

1 . A process for treating a biomass to separate components from the biomass, the process comprising:

(a) reducing the size of the biomass to provide biomass fibers of a suitable size for processing;

(b) subjecting the biomass fibers to an apparatus to mechanically internally fibri Hate the fibers to alter the cell walls of the fibers to facilitate the separation process;

(c) subjecting the fibrillated biomass fibers to an aqueous solution comprising a basic composition and an oxidation agent to pulp the fibers; and

(d) separating the pulped fibers from the solution of step (c) to provide an extract of the biomass separate from the pulped fibers.

2. The process of Claim 1 , further comprising forming the pulped fibers into paper grade pulp.

3. The process of Claim 1 , further comprising repeating steps (b) and (c) on the pulped fiber and separating the pulped fibers subjected to the repeated steps from the aqueous solution and forming the pulped fibers into dissolving grade pulp having an alpha cellulose content of greater than about 90 percent.

4. The process of claim 1 , wherein the apparatus comprises two or more disks to abrade the reduced size biomass fibers to mechanically internally fibril late the fibers.

5. The process of claim 1 , wherein the solution of step (c) further includes a catalyst.

6. The process of claim 5, wherein the catalyst comprises a transition metal catalyst selected from the group consisting of iron, manganese, and cobalt.

7. The process of claim 1 , wherein the biomass fibers are screened prior to step (c) and subjecting to the pulping solution.

8. The process of claim 1 , further comprising the step of subjecting the pulped fibers to a membrane or a centrifuge or both to separate the cellulose, hemicellulose and/or lignin components of the biomass fibers from the pulped fibers.

9. The process of claim 6, further comprising de-watering the pulped fibers.

10. The process of Claim 1 , wherein the basic composition is sodium hydroxide and the oxidation agent is hydrogen peroxide.

11 . The process of Claim 1 , wherein the biomass is a land-based plant biomass.

12. The process of Claim 1 , wherein the biomass is a marine-based plant biomass.

13. The process of Claim 1 wherein step (b) of mechanically internally fibrillating the fibers is done over a short time frame of less than 10 seconds.

14. The process of Claim 2, further including coating a paper article of manufacture formed from the paper grade pulp with the extract of the biomass.

15. The process of Claim 2, further including the steps of adding water, starch and an extract of the biomass to the paper grade pulp to provide a pulp slurry and forming the pulp slurry into a paper article of manufacture.

16. The process of Claim 15, further including coating a paper article of manufacture formed from the pulp slurry with the extract of the biomass.