Patent Application
20150152598
The present invention relates to a process for isolating components of a biomass. Examples of fractions and extractives provided in the process include the extraction, isolation, and purification of lignin, cellulose, sugars, hemicellulose, fibers and/or extractives.
Natural cellulosic feedstocks are typically referred to as “biomass.” Many types of biomass, including wood, paper, agricultural residues, herbaceous crops, and lignocellulosic municipal and industrial solid wastes have been considered as feedstocks for the production and preparation of a wide range of goods. Plant biomass materials are comprised primarily of cellulose, hemicellulose and lignin, bound together in a complex and entangled gel-like structure along with amounts of extractables, pectins, proteins and/or ash. Thus, successful commercial use of biomass as a chemical feedstock depends on the efficient and/or economical separation and isolation of these various constituents.
Many steps are often required in production, harvesting, storage, transporting, and processing of biomass to yield useful products. One step in the processing is the separation, or fractionation, of the biomass into its major components: extractives, hemicellulose, lignin, and cellulose with smaller amounts of pectins, ash, protein, and cutin. Many approaches have been investigated for disentangling the complex structure of the biomass. Once this separation has been achieved, a variety of paths are opened for further processing of each component into marketable products. For example, the possibility of producing products such as biofuels, polymers and latex replacements from biomass has recently received much attention. This attention is due to the availability of large amounts of cellulosic feedstock, the need to minimize burning or landfilling of waste cellulosic materials, and the usefulness of sugar and cellulose as raw materials substituting for oil-based products.
One component of the biomass that the isolation of which has been of interest is cellulose. Cellulose, particularly delignified cellulose is of particular interest to the paper industry and in the production of biofuels. Cellulose is an organic compound with the formula (C6H10O5)n, a polysaccharide consisting of a linear chain of several hundred to over ten thousand β(1→4) linked D-glucose units. Cellulose is an important structural component of the primary cell wall of green plants, many forms of algae and the oomycetes. Cellulose is an extremely abundant organic polymer on Earth. The cellulose content of cotton fiber is 90%, that of wood is 40-50% and that of dried hemp is approximately 45%. Cellulose is mainly used to produce paperboard and paper. Smaller quantities are converted into a wide variety of derivative products such as cellophane and rayon. Using cellulose as a feedstock can be problematic if the cellulose has been denaturated and/or degraded due to harsh conditions such as high temperature, high pressure chemical exposure, high acidic conditions and/or high basic conditions.
Thus, there continues to be a need for improved systems and methods for providing cellulose and cellulose substantially devoid of lignin, hemicellulose, other sugars and ash that take into consideration factors such as environmental and energy concerns, efficiency and cost-effectiveness, while limiting the denaturating and/or degrading of the cellulose composition.
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 Detailed 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.
The present invention provides a process for isolating cellulose that may be adapted to large-scale production, uses environmentally friendly solvents and/or is energy efficient. Moreover, the present invention provides a process for isolating and delignifying cellulose wherein the cellulose is substantially devoid of lignin, hemicellulose, other sugars, and various other water insoluble components, while maintaining its structure substantially similar to that of it in the biomass.
The process includes subjecting the biomass to conditions to isolate the cellulose from the biomass in a non-denaturated or non-degraded form and then subjecting the cellulose to oxidation to remove any remaining hemicelluloses, lignin, and the like to purify the cellulose fraction. The process includes pretreating the biomass to, for example, remove a substantial portion of the hemicellulose component. Pretreatment may include mechanically altering the fibers to, for example, open up the fibers and to form a fluidized biomass. The biomass with opened up fibers is then subjected to high frequency pulses and shear forces without denaturing the individual components of the biomass. The biomass is then subjected to compressive force to separate a first liquid fraction from a first fractionated biomass. The first fractionated biomass may again then be subjected to the same high frequency pulses and shear forces as previously, particularly if there are hemicellulose and/or sugars still present in the first fractionated biomass. Compressive forces are used to separate a second liquid fraction from a second fractionated biomass. The second fractionated biomass is high in cellulose and water insoluble components including lignins and proteins, and is substantially devoid of hemicelluloses and sugars. The second fractionated biomass is subjected to oxidation. The second fractioned biomass is then subjected to compressive forces to separate one or more water insoluble components of the biomass in water soluble and liquid form from a second fractionated biomass high in cellulose and substantially devoid of hemicellulose, sugar and the water insoluble components of the biomass, particularly lignin.
The cellulose of the second fractionated biomass is not denatured or degraded, i.e., it is substantially similar to the cellulose in the biomass prior to isolation. It is believed that because the process of the present invention avoids high temperature, high pressure, extreme chemical conditions, high acidic or basic conditions, and the like, denaturing and/or degrading the cellulose is avoided and provides the delignified cellulose in a form particularly suitable as a feedstock.
In the following detailed description, embodiments of the present invention are described in detail to enable practice of the invention. Although the invention is described with reference to these specific embodiments, 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.
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 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. The invention includes numerous alternatives, modifications, and equivalents as will become apparent from consideration of the following detailed description.
It will be understood that although the terms “first,” “second,” “third,” “a),” “b),” and “c),” etc. may be used herein to describe various elements of the invention should not be limited by these terms. These terms are only used to distinguish one element of the invention from another. Thus, a first element discussed below could be termed a element aspect, and similarly, a third without departing from the teachings of the present invention. Thus, the terms “first,” “second,” “third,” “a),” “b),” and “c),” etc. are not intended to necessarily convey a sequence or other hierarchy to the associated elements but are used for identification purposes only. The sequence of operations (or steps) is not limited to the order presented in the claims or figures unless specifically indicated otherwise. Steps may be conducted simultaneously.
Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the present application and relevant art and should not be interpreted in an idealized or overly formal sense unless expressly so defined herein. 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. All publications, patent applications, patents and other references mentioned herein are incorporated by reference in their entirety. In case of a conflict in terminology, the present specification is controlling.
Also as used herein, “and/or” refers to and encompasses any and all possible combinations of one or more of the associated listed items, as well as the lack of combinations when interpreted in the alternative (“or”).
Unless the context indicates otherwise, it is specifically intended that the various features of the invention described herein can be used in any combination. Moreover, the present invention also contemplates that in some embodiments of the invention, any feature or combination of features set forth herein can be excluded or omitted. To illustrate, if the specification states that a complex comprises components A, B and C, it is specifically intended that any of A, B or C, or a combination thereof, can be omitted and disclaimed.
As used herein, the transitional phrase “consisting essentially of” (and grammatical variants) is to be interpreted as encompassing the recited materials or steps “and those that do not materially affect the basic and novel characteristic(s)” of the claimed invention. See, In re Herz, 537 F.2d 549, 551-52, 190 U.S.P.Q. 461, 463 (CCPA 1976) (emphasis in the original); see also MPEP §2111.03. Thus, the term “consisting essentially of” as used herein should not be interpreted as equivalent to “comprising.”
The term “about,” as used herein when referring to a measurable value, such as, for example, an amount or concentration and the like, is meant to encompass variations of ±20%, ±10%, ±5%, ±1%, +0.5%, or even ±0.1% of the specified amount. A range provided herein for a measurable value may include any other range and/or individual value therein.
The term “biomass” includes any non-fossilized, i.e., renewable, organic matter. The various types of biomass may include plant biomass, animal biomass (any animal by-product, animal waste, etc.) and municipal waste biomass (residential and light commercial refuse with recyclables such as metal and glass removed).
The term “plant biomass” or “ligno-cellulosic biomass” includes virtually any plant-derived organic matter (woody or non-woody) available for energy on a sustainable basis. “Plant-derived” necessarily includes both sexually reproductive plant parts involved in the production of seed (e.g., flower buds, flowers, fruit, nuts, and seeds) and vegetative parts (e.g., leaves, roots, leaf buds and stems). Plant biomass can include, but is not limited to, agricultural crop wastes and residues such as corn stover, wheat straw, rice straw, sugar cane bagasse and the like. Plant biomass further includes, but is not limited to, woody energy crops, wood wastes and residues such as trees, softwood forest thinnings, barky wastes, sawdust, paper and pulp industry waste streams, wood fiber, herbal plant material brewing wastes, and the like. Additionally grass crops, such as switchgrass and the like have the potential to be produced in large-scale amounts and to provide a significant source of another plant biomass. For urban areas, potential plant biomass feedstock comprises yard waste (e.g., grass clippings, leaves, tree clippings, brush, etc.) and vegetable processing waste.
The biomass comprises three basic chemical components/fractions, namely hemicellulose, cellulose, and lignins. The biomass may also include lesser amounts of proteins, extractives, pectins, cutin, and ash depending on the biomass. Specifically, hemicellulose is a polymer (matrix 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 is also easy to cleave via hydrolysis. In contract, cellulose is a linear polymer (polysaccharide) of glucose sugars bonded together by β-glycosidic linkages to form lengthy linear chains. Hydrogen bonding can occur between cellulose chains 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.
Typical ranges of hemicellulose, cellulose, and lignin in, for example, a plant biomass such as corn stover are:
“Ambient temperature” includes the temperature of the surroundings in which the process of the invention takes place. Ambient temperature may include, but is not limited to, “room temperature,” and any temperature within the range of about 0 to about 40° C. (30 to 104° F.).
Individual components of the biomass may include, but are not limited to, lignin, cellulose, hemicellulose, others sugars, proteins, pharmaceuticals, nutraceuticals, 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.
“Alcohol” includes, but is not limited to, methanol, ethanol, isopropanol, propanol, isobutanol, butanol, and glycol. A “short chain alcohol” generally includes C1 to C4 alcohols.
“Water” includes, but is not limited to, deionized water, spring water, distilled water, mineral water, tap water and well water, and mixtures thereof. “Water soluble” includes a component that can be dissolved in water or other solvent at ambient temperature. “Water insoluble” includes a component that cannot be dissolved in water or other solvent at ambient temperature.
Referring now to
As briefly discussed above, in an initial pretreatment step 90 the biomass may be pre-soaked and contacted with a solvent such as with an alcohol, an aqueous alcohol, water or glycerin or co-solvent or mixture thereof in order to begin the fractionation or extraction of the biomass, particularly to begin isolating the hemicelloses from the biomass. The biomass may swell during this pretreatment step 90. The biomass may be disassembled 110 such as by chopping, cutting, fraying, attrition or crushing prior to contact with the solvent 100. In a particular embodiment, if the biomass is, for example, fresh plant biomass or herbal plant material, the material may be contacted with alcohol. If the biomass is dried plant biomass or herbal plan material, it may be contacted with an aqueous alcoholic solution. This aqueous alcoholic extraction may be performed in aqueous alcohol at different concentrations. Suitable alcohols may be short chain alcohol, such as, but not limited to, methanol, ethanol, propanol, isopropanol, butanol and isobutanol. In a particular embodiment, the alcohol is ethanol. The alcohol may be a co-solvent mixture such as a mixture of an alcohol and water. The aqueous alcoholic solution may comprise from 0-100% (v/v) alcohol. More particularly, the aqueous alcoholic solution may comprise from 25-95% (v/v) alcohol. In a particular embodiment, the aqueous alcoholic solution is 25% (v/v) or more alcohol. In another particular embodiment, the aqueous alcohol may be 60% (v/v) alcohol. In another embodiment, the aqueous alcoholic solution may be 70% (v/v) alcohol. In yet another embodiment, the aqueous alcoholic solution may be 86% or more (v/v) alcohol. In yet other embodiments, the process for fractionating or extracting biomass may comprise contacting the biomass with glycerin or an aqueous glycerin solution.
In yet another embodiment, the process for extracting biomass may comprise contacting the biomass with water via contacting with steam to provide a 20 to 40 percent moisture gain. Typically, in other embodiments of the invention, the ratio of biomass/solids contacted with a solvent/liquids used may be 1:1 to 1:10 of solids to liquid. During contact with the solvent (alcohol or water) the fibers of the biomass may swell.
With respect to disassembling the fibers, the fibers are initially opened up by chopping, cutting, fraying, attrition or crushing the biomass and are thereby provided in a fluidized or flowable form. For example, the biomass fibers may be processed in a mechanical high consistency fluidization machine such as a refiner or disk mill. An exemplary disk mill is available from Sprout Waldron, Beloit or Andritz. By utilizing a refiner or disk mill, the biomass and particularly the fibrous material thereof may be altered without destroying the fibrous nature of the fibrous material so that the high frequency pulses and shear forces of the fractionation apparatus are accessible to the fibrous material. The processing may take place for any amount of time necessary as would be understood by one of skill in the art as necessary to affect this step. In a particular embodiment, the disassembly process is performed for one minute or less.
The overall pretreatment step 90 may take place for any period of time that is sufficient for the fractionation or extraction process and may take place in any vessel, container or mixer suitable for contacting the biomass with a solvent and/or disassembling the fibers. In some embodiments, the pretreatment step may be any length of time between, for example, 15 minutes, 30 minutes or one hour, and 72 hours. In another embodiment, the pretreatment step may be 15 minutes or less. The pretreatment step may be one minute or less. In the pretreatment step, the biomass in contact with the solvent may optionally be subjected to a compressive force, which can facilitate absorption of the solvent into the biomass. The compression in the pretreatment step 90 may take place according to any technique that will be appreciated by one of skill in the art. In an embodiment of the invention, compression during the pretreatment step may be affected by a screw press.
In another embodiment, the pretreatment may include the addition of a mild acid to prehydrolyze the biomass to facilitate removal of the hemicellulose. Suitable acids for acidifying the pretreatment solution (solvent) include inorganic acids such as nitric acid, hydrochloric acid and phosphoric acids, and organic acids, such as acetic acid or formic acid. It is recognized that the addition of mild acids like acetic acid or formic acid may not be necessary because of natural amounts of the same being present in the biomass. If acidification/hydrolysis is desired, the pH of the solution will be about 0.5 to 7.0 and often may be between about 1.0 to 5.0. A sequestering agent or chelating agent such as an aminocarboxylic acid or aminopolyphosphoric acid may also be used.
Additionally a compound to help catalyze delignification may be included. In one embodiment, an anthraquinone (AQ) may be utilized. Exemplary anthraquinones and derivatives thereof including 1-methylanthrazuinone, 2-methylanthraquinone, 2-ethylanthraquinone, 2-methoxyanthraquinone, 2,3-dimethylantraquinone, and 2,7-dimethylantraquinone.
In another embodiment an alkaline buffer such as an alkaline metal hydroxide, carbonate, phosphate, or borate may be included to facilitate separation of the hemicellulose and lignin individual components. Suitable buffers may include sodium hydroxide, sodium carbonate, and sodium borate. Mixtures or blends of the hydroxides, carbonates, and borates may be used. If an alkaline metal hydroxide is added, the pH may be between about 7.0 to about 13.0 and often may be between about 8.0 to about 11.0.
The pretreatment step 90 to hydrate or rehydrate the biomass may be conducted at ambient temperature, elevated temperature (20° C. to 90° C.) or using steam/vapor (greater than 100° C.). It is recognized that the vapor may be of the solvent.
Isolation or removal of the hemicelluloses may be accomplished at this stage. Ultrafiltration or diafiltration may be utilized to provide a retentate having 80 to 95 percent of the hemicelluloses of the biomass and a permeate comprising the biomass with a substantial portion of the hemicelluloses removed. It is noted that the retentate may include isolated organic acids such as acetic acid or formic acid which may be removed from the retentate and used to pretreat the biomass as described above. The hemicelluloses may be dried to avoid fermentation or mold production and then used as a raw material for ethanol production, for example.
Overall the desire is to provide the fibers in a form wherein the components of the fibers can be readily fractionated using the high shear forces and pulses of the fractionation apparatus with a substantial portion of the hemicelluloses having been removed. The selection of the conditions of the pretreatment step 90 such as solvent choice, temperature, pressure, time, additives, and the like will be dependent on the biomass and the components of that biomass to be fractionated and isolated, and will be within the skill of one in the art without undue experimentation. Extreme and harsh conditions may be avoided so as to not denature and/or degrade the cellulose component.
Following removal of the hemicelluloses 105, the biomass is in fluid or flowable form may be subjected to fractionation 120 to fractionate or extract the biomass using shear forces and pulsation. It will be appreciated that in a particular embodiment, shear forces and pulsation are used in which the components of the biomass are not denatured or altered, and the chemical properties of the individual components are maintained wherein a portion of the fractions or extracts may be separated from the biomass. The subjecting of the biomass to shear forces and high frequency pulses may take place for any amount of time necessary as would be appreciated by one of skill in the art as necessary to affect this step. In a particular embodiment, this step may takes place for one minute or less. In operation the fluidized biomass is rapidly accelerated from about 4 mph to about 120 mph under greater than 1000 pulses per second of energy while avoiding attrition of the biomass particles. This facilitates the ability of the cellular structure of the biomass to release its various fractions or constituents from the complex and entangled structure of the biomass without having the chemical properties and characteristics of the components being denatured or degraded.
The fractionated biomass material may then be subjected to a compression force 130 e.g., a crushing or macerating force optionally in the presence of additional solvent, wherein the compression force removes liquid fraction for collection while discharging a low liquid solids cake primarily being cellulose. The compression force may be applied according to any technique that is appreciated by one of skill in the art. In a particular embodiment, the compression force is affected by screws of a screw press that macerate the fractionated biomass and may include optional stirring.
The steps of subjecting to fractionation 120 and subjecting to fractionation can continue until the biomass fraction is substantially free of hemicellulose and sugars. This can be monitored or measured in a wide variety of matters including using a brix meter to measure sugar content, differential scanning calorimeter (DSC) to measure melt temperatures and differential thermal analysis (DTA) to measure area under melt curves.
In one embodiment, the first fractionated biomass may be subjected to conditions to raise the pH of the first fractionated biomass to above about 9. For example, the biomass may be contacted with mild caustic, e.g. 0.1 to 0.5% w/w based upon water, sodium hydroxide.
The fractions or extracts provided according to the present invention may be further processed as outlined in
Once the fractionated biomass is substantially free of hemicellulose and sugars, the biomass is subjected to oxidation at a pH above 7 noting that the fractionated biomass typically has a pH of about 7 and is about 9. In one embodiment, oxidation occurs by contacting the fractionated biomass with about 0.1 to about 5 percent hydrogen peroxide. For example, with respect to lignin removal, isolation, and purification, the hydrogen peroxide allows the lignin ether bond to cleave. Specifically, the phenolic groups in the lignin are ionized and the resulting radical is mainly of the phenoxyl radical type. Then hydrogen peroxide is formed through dismutation of the superoxide anion. The superoxide anion itself is not very reactive but the decomposition products of hydrogen peroxide include the very reactive hydroxyl radical. The hydroxyl radical not only reacts with the lignin structures but also readily attacks the polysaccharides with subsequent glycosidic bond cleavage and the creation of new sites for peeling reactions. Once the perhydoxyl radical attaches to the lignin (or protein or water insoluble extractive) these individual components of the biomass become more polar and water soluble. Other oxidation agents include alkali metal peroxides such as organic and inorganic peroxides including sodium peroxide, calcium peroxide, magnesium peroxide, and sodium percarbonate. Moreover this reaction can be facilitated by inclusion of anthraquinone or its derivatives or other catalysts in the pretreatment step.
In another embodiment, an oxidation mixture is formulated. The oxidation mixture is provided by mixing together an alkaline buffer such as alkaline metal hydroxide, carbonate, phosphate, or borate, a source of oxyanions and a short chain organic acid to provide an oxidation mixture. Suitable alkaline buffers include sodium hydroxide, sodium carbonate and sodium borate. Suitable sources of oxyanions include hydrogen peroxide and organic and inorganic peroxides such as sodium peroxide, calcium peroxide, magnesium peroxide, and sodium percarbonate. Optionally, sulfuric acid or sodium sulfate (i.e., a source of S2− or HS− ions) may be included as an oxyanionic nucleophilic sulfide catalyst to facilitate delignification. Such will also facilitate base catalyzed esterification and transesterification of the cellulose when used as a feedstock. In one embodiment, the oxyanions may be generated electrically by ozonation. Suitable short chain organic acids may include acetic acid (vinegar) and formic acid. A stabilized catalyst mixture is provided by mixing together an alkali metal carbonate stabilizer such as sodium carbonate or sodium bicarbonate and a manganese catalyst. An exemplary manganese catalyst is a chelated manganese acid such as a manganese amino acid chelate. The stabilized catalyst mixture in one embodiment may be in powder solid form.
The stabilized catalyst mixture is then applied to the second fractionated biomass, for example, by mixing the catalyst in powder form with the second fractionated biomass. The liquid oxidation mixture is then added to the second fractionated biomass and mixed, and oxidation is allowed to occur for about one minute to about 48 hours. The oxidized second fractionated biomass is then subjected to compressive force with optional spinning to provide a third fractionated biomass low in lignin (i.e., often less than about 4 to about 8 percent), and a third liquid fraction high in lignin. The third fractionated biomass may again be oxidized as above and subjected to a compressive force with optional spinning to provide a fourth fractionated biomass substantially lower in lignin (i.e., often less than about 2 to about 4 percent and a four liquid fraction substantially high in lignin. The isolating of the biomass steps and repeated contacting with the oxidation mixture followed by compression can be repeated multiple times until the fractionated biomass has less than about 0 to about 2 percent lignin with the last step(s) being a conventional water rinse step.
After separation, the now water soluble individual components, e.g., the lignin, can be further separated, isolated and/or purified, such as described in copending U.S. application Ser. No. ______, filed Feb. 11, 2015 (Attorney Docket No. 1237-4IP2), the disclosure of which is incorporated herein by reference in its entirety. In one embodiment, the centrifugation is used to provide a decant. Then, for example, ultrafiltration or diafiltration membranes, available from Millipore, Billerica, Mass., may be used. A first membrane can be used to remove any remaining hemicellulose from the liquid fraction. In one embodiment, the first membrane is a 10K dalton screen. The retentate will comprise the hemicellulose and the permeate will primarily comprise lignins, proteins, and extractives with a small amount of hemicellulose, sugars, and fiber fragments. The second membrane will isolate the lignin, protein or extractive depending on the membrane as a retentate and any remaining hemicellulose, sugars, fragments, contaminants (e.g., heavy metals) as the permeate. In one embodiment, the second membrane is an 8K dalton screen. A further 3K dalton screen can be used to further isolate the desired component. The cellulose may be subjected to based catalyzed esterification or transesterification.
In a particular embodiment, the cellulose and/or cellulose pulp provided by the fractionation and/or extraction process of the present invention can be used or applied in the preparation of paper and paper products. Examples of paper products include, but are not limited to: paper; paperboard; and card stock. Use of the paper products prepared from the cellulose and/or cellulose pulp provided by the present invention is not particularly limited. The paper products can be produced with a wide variety of properties, depending on its intended use, which range from, for example: representing value, such as in paper money, bank notes, checks, security, vouchers and tickets; for storing information, such as in books and notebooks, scrapbooks, magazines, newspapers, art, letters; for personal use, such as in diaries, notes to oneself, etc. and scratch paper; for communication, such as in communication between individuals and/or groups of people; for packaging and containers, such as in paperboard, kraft board, containerboard, linerboard, beverage and/or food containers, liquid containers, corrugated boxes, paper bags, envelopes, wrapping tissue, Charta emporetica and wallpaper; for cleaning, such as in toilet paper, handkerchiefs, paper towels, facial tissue and cat litter; for construction, such as in papier-mâché, origami, paper planes, quilling, paper honeycomb, used as a core material in composite materials, paper engineering, construction paper and paper clothing; and other uses, such as in emery paper, sandpaper, blotting paper, litmus paper, universal indicator paper, paper chromatography, electrical insulation paper (see also dielectric and permittivity) and filter paper.
The method by which the cellulose and/or cellulose pulp provided by the present invention is used in the production of paper and paper products is not particularly limited, and any method that would be appreciated by one of skill in the art may be used in the production of paper and paper products using the cellulose and/or cellulose pulp provided by the present invention. For example, the cellulose pulp provided according to the present invention can be fed to a paper machine where it is formed as a paper web and the water is removed from it by pressing and drying. The cellulose pulp provided by the present invention may also be bleached to make the pulp whiter. Typical chemicals and processes used in the bleaching of pulp include: chlorine; sodium hypochlorite; extraction with sodium hydroxide; oxygen; alkaline hydrogen peroxide; ozones; chelation to remove metals; enzyme treatment; peroxy acids; and sodium dithionite. Typical chelation agents include, but are not limited to, EDTA and DTPA. Although not particularly limited by the method of bleaching of the cellulose and/or cellulose pulp provided by the present invention, elemental chlorine free (ECF) and/or total chlorine free (TCF) methods of bleaching provide more environmentally friendly methods of bleaching. TCF bleaching, for example, prevents the formation of toxic chemicals such as dioxins. An example of a TCF sequence for the bleaching of pulp is wherein the pulp would be treated with oxygen, then ozone, washed with sodium hydroxide then treated in sequence with alkaline peroxide and sodium dithionite.
In other embodiments, the cellulose and/or cellulose pulp provided according to the present invention can be used or applied in the preparation and/or manufacture of paper coatings. Cellulose and cellulose derivatives have been used to coat papers to enhance physical characteristics, for example, but not limited to, appearance, e.g., glossiness and finish, strength, rigidity and water resistance. The manner in which the paper coatings prepared from the cellulose and/or cellulose pulp provided according to the present invention is not limited and the method used may be any that would be appreciated by one of skill in the art.
In yet other embodiments, the cellulose and/or cellulose pulp provided according to the present invention can be used in the preparation of fibers. Examples of fibers include, but are not limited to, regenerated cellulose fibers, for example, cellophane and rayon.
In yet other embodiments, the cellulose and/or cellulose pulp provided according to the present invention can be used in consumables. The type of consumable is not particularly limited, and applications can include, but are not limited to: microcrystalline cellulose or powdered cellulose used as inactive fillers in drug tablets; thickeners and/or stabilizers Powdered cellulose may also be used to improve characteristics of processed foods or foodstuffs, for example, to prevent caking and/or clumping of the processed food or foodstuffs within a container.
In yet other embodiments, the cellulose and/or cellulose pulp provided according to the present invention can be used in scientific applications. Cellulose is commonly used in the laboratory as the stationary phase for chromatography, in particular, thin layer chromatography. Liquid and gel filtration typically use products prepared from cellulose, either alone or in combination with other filtration media, for example, diatomaceous earth. Various filtration made may comprise the cellulose of the invention.
In yet other embodiments, the cellulose and/or cellulose pulp provided according to the present invention can be used in construction and building materials. Cellulose insulation made from recycled paper is becoming popular as an environmentally preferable material for building insulation. It can be treated with boric acid as a fire retardant. Moreover, hydrogen bonding of cellulose in water can produce a sprayable, moldable material as an alternative to the use of plastics and resins. The recyclable material can be made water and/or flame-resistant or fire retardant, and can provide sufficient strength for use as a building material.
In another embodiment, the cellulose can be treated with cellulose enzymes to hydrolyze the crystalline cellulose to glucose followed by fermentation of the glucose with yeast or suitable microorganism to provide biofuel and/or bio feedstock. It is recognized that the hemicellulose and/or sugars previously separated from the fractionated biomass may be added back to be co-fermented with the cellulose.
In another particular embodiment, fractionation or extraction according to the invention provides hemicelluloses and sugars. Sugars and/or hemicelluloses provided by the process according to the invention may further be used in the preparation of biofuels such as, but not limited to, ethanol or the preparation of polymers/plastics. One such embodiment is the fermentation of the provided fractions to produce the ethanol. In another embodiment, the polymer is polylactic acid (PLA). In another embodiment the lignin may be further separated and emulsified for further processing. Because the lignin has not been subjected to high temperatures, its functional groups have not chemically reacted and the isolated lignin may be more reactive.
The following example is provided to illustrate the present invention, and should not be construed as limiting thereof.
10 Kg of dried wheat grass (straw) is chopped to a stalk length of ¾ to 2 inches. The straw was briefly rinsed with cold clean water to remove sand and dirt. The wheat straw is then subjected to water or steam injection into a disk mill for a few seconds to mechanically disassemble the cellulosic structure. The fluidized wheat grass is then subjected to high shear forces for 1.5 to 3 seconds with pulses of 1824 to 912 times without denaturing and/or degrading the components of the wheat straw. The combined mixture is subjected to compressive forces to separate the stream into liquid and a 20-60% cellulosic solids fractions. The liquid fraction containing hemicellulose is retained.
The solid fraction is pretreated with NaOH sufficient to raise the pH of the cellulosic water slurry from about 4-7 to 10-12. This basic mixture is allowed to age from a few seconds to 1 hour and again processed through the system starting at the disk mill which is subjected to water or steam injection in the mill for a few seconds to mechanically disassemble the cellulosic structure. The fluidized wheat grass is then subjected to high shear forces for 1.5 to 3 seconds with pulses of 1824 to 912 times without denaturing the components of the wheat straw. The combined mixture is subjected to compressive forces to separate the stream into liquid and a 20-60% cellulosic solids fractions. The liquid fraction containing hemicellulose is added to the first and second fraction and undergoes further processing.
The solid fraction is treated with an oxidation agent hydrogen peroxide, sufficient to raise the pH of the cellulosic water slurry from about 10-12 to 8-10. This basic mixture is allowed to age from a few seconds to 1 hour and again processed through the system starting at the disk mill which is subjected to water or steam injection in the mill for a few seconds to mechanically disassemble the cellulosic structure. The fluidized wheat grass is then again subjected to high shear forces for 1.5 to 3 seconds with pulses of 1824 to 912 times without denaturing the components of the wheat straw. The combined mixture is screened and subjected to compressive forces to separate the stream into liquid and a 20-60% cellulosic solids fractions. The liquid fraction containing lignin is retained. The solid fraction is then treated again to raise the pH and the liquid fraction containing hemicellulose is added to the first and second fraction and undergoes further processing. The solid fraction is then treated with an oxidation agent and rerun through the fractionation unit. The liquid fraction containing lignin is added to the first liquid lignin fraction and further separated using a membrane.
423 grams of dry switch grass is steam activated to rehydrate at about 25 to 50 percent water in a single disk refiner to provide the switch grass in a fluidized or flowable condition. Naturally occurring carboxylic acids (acetic acid and formic acid) with the switch grass lower the pH to below 3. The hydrated/activated switch grass is subjected to compressive force to separate a liquid high in hemicelluloses and a biomass high in cellulose and lignin. The hemicellulose/liquid is then subjected to a 1 to 5 kD ultrafiltration membrane to remove the acetic acid and formic acid as a permeate for reuse in the process.
The biomass is then subjected to high frequency pulses and shear forces without denaturing and/or degrading the lignin using the Green Extraction Technology fractionation apparatus described in U.S. application Ser. No. 14/454,833 filed on Aug. 8, 2014. The biomass is fractionated for about 15 to about 30 seconds at pulses of 912 to 1824 to provide a first fractionated biomass and a first liquid fraction. The first fractionated biomass is contacted with 0.3% w:w based upon water sodium hydroxide to raise the pH above about 9. The first fractionated biomass is then subjected to compressive force to separate a second liquid fraction with most of the remaining hemicellulose from a second fractionated biomass high in cellulose and lignins.
The second fractioned biomass is then subjected to oxidation to separate the lignin from the cellulose. An oxidation mixture is formed and comprises 2000 ml of hydrogen peroxide at 3% buffered with 60 g of sodium hydroxide and 300 ml of acetic acid. A catalyst/stabilizer mixture is formed by mixing 2 g of sodium carbonate stabilizer and 15 mg of manganese amino acid chelate catalyst in powder form. The powdered catalyst/stabilizer mixture is applied to the second fractionated biomass and then it is contacted with the liquid oxidation mixture and oxidized for 60 minutes. The oxidized second fractionated biomass is subjected to compressive forces using a two screw press with stirring to provide a third fractionated biomass high in cellulose with a lignin content of less than 7% and a third liquid fraction high in water soluble lignin. The third fractionated biomass is then oxidized again for 60 minutes using 1500 ml hydrogen peroxide and the same amounts of the other components of the oxidation mixture and the catalyst/stabilizer mixture. The oxidized third fractionated biomass is then subjected to compressive forces to provide a fourth fractionated biomass high in cellulose with a lignin content of less than 7% and a fourth liquid fraction high in lignin. The entire oxidation process is then repeated using 1000 ml hydrogen peroxide oxidized for 120 minutes and then subjected to compressive force to provide a fifth fractionated biomass high in cellulose having a lignin content of less than 5%.
DSCs of a third fractionated biomass are provided in
423 grams of dry wheat straw is steam activated to rehydrate at about 25 to 50 percent water in a single disk refiner to provide the switch grass in a fluidized or flowable condition. Naturally occurring carboxylic acids (acetic acid and formic acid) within the wheat straw lower the pH to below 3. The hydrated/activated wheat straw is subjected to compressive force to separate a liquid high in hemicelluloses and a biomass high in cellulose and lignin. The hemicellulose/liquid is then subjected to a 1 to 5 kD ultrafiltration membrane to remove the acetic acid and formic acid as a permeate for reuse in the process.
The biomass is then subjected to high frequency pulses and shear forces without denaturing and/or degrading the lignin using the Green Extraction Technology fractionation apparatus described in U.S. application Ser. No. 14/454,833 filed on Aug. 8, 2014. The biomass is fractionated for about 15 to about 30 seconds at pulses of 912 to 1824 to provide a first fractionated biomass and a first liquid fraction. The first fractionated biomass is contacted with 0.3% w:w based upon water sodium hydroxide to raise the pH above about 9. The first fractionated biomass is then subjected to compressive force to separate a second liquid fraction with most of the remaining hemicellulose from a second fractionated biomass high in cellulose and lignins.
The second fractioned biomass is then subjected to oxidation to separate the lignin from the cellulose. An oxidation mixture is formed and comprises 2000 ml of hydrogen peroxide at 3% buffered with 60 g of sodium hydroxide and 300 ml of acetic acid. A catalyst/stabilizer mixture is formed by mixing 2 g of sodium carbonate stabilizer and 15 mg of manganese amino acid chelate catalyst in powder form. The powdered catalyst/stabilizer mixture is applied to the second fractionated biomass and then it is contacted with the liquid oxidation mixture and oxidized for 60 minutes. The oxidized second fractionated biomass is subjected to compressive forces using a two screw press with stirring to provide a third fractionated biomass high in cellulose with a lignin content of less than 7% and a third liquid fraction high in water soluble lignin. The third fractionated biomass is then oxidized again for 60 minutes using 1500 ml hydrogen peroxide and the same amounts of the other components of the oxidation mixture and the catalyst/stabilizer mixture. The oxidized third fractionated biomass is then subjected to compressive forces to provide a fourth fractionated biomass high in cellulose with a lignin content of less than 7% and a fourth liquid fraction high in lignin. The entire oxidation process is then repeated using 1000 ml hydrogen peroxide oxidized for 120 minutes and then subjected to compressive force to provide a fifth fractionated biomass high in cellulose having a lignin content of less than 5%.
The wheat straw fractionated biomass was analyzed for percent lignin contact, Kappa number, and fiber quality. The results are provided in Table 1.
Example 3 was repeated with wild oats. The wild oats fractionated biomass was analyzed for lignin contact and Kappa number. The results are provided in Table 2.
Example 2 is repeated except the oxidized fifth fractionated biomass is subjected to oxidation using 1000 ml hydrogen peroxide again. This pulp is then combined with Northern bleached softwood kraft (“NBSK”) at a 80 percent pulp of the invention/20 percent NBSK blend to which is added 8 percent calcium carbonate. This is made into paper to mimic ink jet type papers.
Example 3 is repeated except the oxidized fifth fractionated biomass is subjected to oxidation using 1000 ml hydrogen peroxide again. This pulp is then combined with Northern bleached softwood kraft (“NBSK”) at an 80 percent pulp of the invention/20 percent NBSK blend to which is added 8 percent calcium carbonate. This is made into paper to mimic ink jet type papers.
Table 3 provides testing against commercially available ink jet paper for paper made according to Examples 5 and 6.
This shows that the papers of the invention have significantly higher strength and toughness as compared to the control paper due to the avoidance of denaturing and/or degrading the cellulose using the process of the invention.
Although selected embodiments of the present invention have been disclosed for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims.
This application is a continuation-in-part of U.S. application Ser. No. 14/454,972, filed Aug. 8, 2014, which claims priority to U.S. Provisional Patent Application Ser. No. 61/864,853, filed Aug. 12, 2013, U.S. Provisional Patent Application Ser. No. 61/909,418, filed Nov. 27, 2013, and U.S. Provisional Patent Application Ser. No. 61/919,194, filed Dec. 20, 2013, the disclosures of which are incorporated herein by reference in their entirety.
| Number | Date | Country | |
|---|---|---|---|
| 61864853 | Aug 2013 | US | |
| 61909418 | Nov 2013 | US | |
| 61919194 | Dec 2013 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 14454972 | Aug 2014 | US |
| Child | 14619406 | US |
