CN110832139A

CN110832139A - Nanohllocelluiose compositions and methods for producing these compositions

Info

Publication number: CN110832139A
Application number: CN201880040716.0A
Authority: CN
Inventors: K·尼尔森; T·雷特斯纳
Original assignee: API Intellectual Property Holdings LLC
Current assignee: Granbio Intellectual Property Holdings LLC
Priority date: 2017-06-22
Filing date: 2018-06-22
Publication date: 2020-02-21
Also published as: EP3642415A4; ZA201908402B; BR112019027082B1; JP2023060307A; BR112019027082A2; JP2020525659A; AU2018290293A1; EP3642415A1; RU2019140283A3; AU2018290293B2; WO2018237216A1; RU2019140283A; CA3067586A1

Abstract

Some variations provide a novel nano-lignocellulosic composition comprising, on a dry-out, ash-free and acetyl-free basis: 35 to 80 wt% of cellulose nano-fibrils, cellulose microfibrils, or a combination thereof; 15 to 45 wt% lignin; and 5 to 20 wt% hemicellulose. Hemicellulose may contain xylan or mannan as a main component. Novel properties result from the hemicellulose content being between the high hemicellulose content of the raw biomass and the low hemicellulose content of conventional nanocellulose. Due to the presence of lignin, the nano-lignocellulosic composition is hydrophobic. Methods for making and using the nano-lignocellulosic compositions are also described.

Description

Nanohllocelluiose compositions and methods for producing these compositions

Priority data

This international patent application claims priority from U.S. provisional patent application No.62/523,293 filed on day 22, 6/2017 and U.S. patent application No.16/014,589 filed on day 21, 6/2018, each of which is incorporated herein by reference.

Technical Field

The present invention relates generally to nanocellulose and related materials produced by fractionating lignocellulosic biomass and further processing the cellulose fraction.

Background

Biomass refining (or biorefinery) is becoming increasingly common in industry. Cellulose fibers and sugars, hemicellulose sugars, lignin, syngas, and derivatives of these intermediates are used to produce chemicals and fuels. Indeed, we have now observed that the commercialization of a comprehensive biorefinery capable of processing incoming biomass is much the same as that of a refinery now processing crude oil. Underutilized lignocellulosic biomass feedstocks have the potential to be much cheaper than petroleum on a carbon basis and much better from an environmental life cycle standpoint.

Lignocellulosic biomass is the most abundant renewable material on the planet and has long been considered as a potential feedstock for the production of chemicals, fuels and materials. Lignocellulosic biomass normally comprises mainly cellulose, hemicellulose and lignin. Cellulose and hemicellulose are natural polymers of sugars, and lignin is an aromatic/aliphatic hydrocarbon polymer that enhances the entire biomass network. Some forms of biomass (e.g., recycled material) do not contain hemicellulose.

Although the most available natural polymers on earth, cellulose has recently emerged as a nanostructured material in the form of nanocrystalline cellulose (NCC), nanofibrillar cellulose (NFC) and Bacterial Cellulose (BC). Nanocellulose is being developed for a wide variety of applications, such as polymer reinforcement, antimicrobial films, biodegradable food packaging, printed paper, pigments and inks, paper and paperboard packaging, barrier films, adhesives, biocomposites, wound healing, drug and drug delivery, textiles, water-soluble polymers, building materials, recyclable interior and structural components for the transportation industry, rheology modifiers, low calorie food additives, cosmetic thickeners, pharmaceutical tablet binders, bioactive papers, pickering stabilizers for emulsion and particle stabilized foams, coating formulations, films for optical switching, and detergents.

The biomass-derived slurry may be converted to nanocellulose by mechanical processing. Although this method may be simple, disadvantages include high energy consumption, damage to fibers and particles due to intensive mechanical treatment, and a broad distribution of fibril diameters and lengths.

There is a need in the art for improved methods of producing nanocellulose from biomass at reduced energy costs. Also, there is a need in the art for improved starting materials (i.e., biomass-derived slurries) for producing nanocellulose. For some applications, it is desirable to produce nanocellulose with high hydrophobicity.

There is also a need in the art to increase the strength of weak cellulosic fibers and to improve certain properties of paper, corrugated medium pulp and pulp products.

Disclosure of Invention

Some variations provide a nano-lignocellulosic composition comprising, on a dry-out, ash-free and acetyl-free basis: about 35 wt% to about 80 wt% of cellulose nano-fibrils, cellulose microfibrils, or a combination thereof; about 15 wt% to about 45 wt% lignin; and about 5 wt% to about 20 wt% hemicellulose. Hemicellulose may contain xylan or mannan as a main component.

In certain embodiments, the composition comprises about 40 wt% to about 70 wt% cellulose nano-fibrils, cellulose micro-fibrils, or a combination thereof on a dry-out, ash-free, and acetyl-free basis.

In certain embodiments, the composition comprises about 45 wt% to about 60 wt% cellulose nano-fibrils, cellulose micro-fibrils, or a combination thereof on a dry-out, ash-free, and acetyl-free basis.

In certain embodiments, the composition comprises about 20 wt% to about 40 wt% lignin on a dry, ash-free and acetyl-free basis.

In certain embodiments, the composition comprises about 25 wt% to about 35 wt% lignin on a dry, ash-free and acetyl-free basis.

In certain embodiments, the composition comprises from about 7 wt% to about 15 wt% hemicellulose on a dry, ash-free and acetyl-free basis.

In certain embodiments, the composition comprises from about 8 wt% to about 14 wt% hemicellulose on a dry, ash free and acetyl free basis.

In some embodiments, the nano-lignocellulosic composition is characterized by at least 99% filtration completion (e.g., 100% completion) in less than 100 minutes.

The invention also provides a pulp product or paper product comprising the disclosed nano-lignocellulosic composition.

Some variations provide a method for producing a nano-lignocellulosic composition, the method comprising:

(a) providing a lignocellulosic biomass feedstock;

(b) digesting the feedstock in a digester with a reaction solution comprising steam and/or hot water under effective reaction conditions to produce a digested stream containing cellulose-rich solids, hemicellulose oligomers and lignin;

(c) optionally washing the cellulose-rich solids to remove at least a portion of the hemicellulose oligomers and/or at least a portion of the lignin from the cellulose-rich solids;

(d) mechanically treating the cellulose-rich solids to form a nano-lignocellulosic composition comprising cellulose nanofibrils and/or cellulose nanocrystals, hemicellulose, and lignin; and

(e) recovering the nano-lignocellulosic composition.

In some methods, the nano-lignocellulosic composition, on a dry-out, ash-free and acetyl-free basis, comprises: about 35 wt% to about 80 wt% of cellulose nano-fibrils, cellulose microfibrils, or a combination thereof; about 15 wt% to about 4 wt% lignin; and about 5 wt% to about 20 wt% hemicellulose.

In some methods, the nano-lignocellulosic composition is characterized by at least 99% filtration completed in less than 100 minutes.

The method may further comprise producing a pulp product or a paper product comprising the nano-lignocellulosic composition. For example, the nano-lignocellulosic composition may be fed to a paper machine to produce a paper product.

Drawings

Fig. 1A is an SEM image of exemplary nanocellulose experimentally produced by refining and homogenizing materials produced by hot water extraction of biomass.

Fig. 1B is an SEM image of an exemplary nanocellulose experimentally produced by refining and homogenizing the material produced by hot water extraction of biomass.

Fig. 1C is an SEM image of exemplary nanocellulose experimentally produced by refining and homogenizing the material produced by hot water extraction of biomass.

Fig. 2 is a 40 x magnified optical micrograph of the washed nanolignocelluloses produced in example 1.

Fig. 3 is a 40 x magnified optical micrograph of the washed nanolignocelluloses produced in example 2.

Fig. 4 is a graph of the filtration rate of the nano lignocellulose of example 2 compared to the kraft pulp of the prior art.

Detailed Description

This description will enable one skilled in the art to make and use the invention, and it describes several embodiments, adaptations, variations, alternatives, and uses of the invention. These and other embodiments, features and advantages of the present invention will become more readily apparent to those of ordinary skill in the art when the following detailed description of the present invention is taken in conjunction with any of the accompanying drawings.

As used in this specification and the appended claims, an expression without a numerical designation includes a plurality of expressions unless the context clearly dictates otherwise. Unless defined otherwise, all 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. All compositional figures and ranges on a percentage basis are weight percentages unless otherwise indicated. All numbers or conditional ranges are intended to include any specific value subsumed within that range, rounded to any suitable decimal point.

Unless otherwise indicated, all numbers expressing parameters, reaction conditions, component concentrations, and so forth, used in the specification and claims are to be understood as being modified in all instances by the term "about". Accordingly, unless indicated to the contrary, the numerical parameters set forth in the following specification and attached claims are approximations that may vary depending at least upon the particular analytical technique.

The term "comprising" is synonymous with "including," "containing," or "characterized by," is inclusive or open-ended and does not exclude additional, unrecited elements or method steps. "comprising" is a term of art used in claim language that means that the specified claim element is essential, but that other claim elements may be added and still form a construct within the scope of the claims.

The phrase "consisting of" as used herein excludes any element, step, or ingredient not expressly recited in the claim. When the phrase "consisting of … …" (or a variant thereof) appears in the subject clause of the claims rather than immediately after the preamble, it is limited only to the elements set forth in that clause; the claims as a whole do not exclude other elements. The phrase "consisting essentially of" as used herein limits the scope of the claims to the explicitly recited elements or method steps, plus those elements or method steps that do not materially affect the basic and novel features of the claimed subject matter.

With respect to the terms "comprising," "consisting of … …," and "consisting essentially of … …," where one of these three terms is used herein, the presently disclosed and claimed subject matter can include the use of either of the other two terms. Thus, in some embodiments not explicitly recited otherwise, any instance of "comprising" may be replaced by "consisting of," or "consisting essentially of.

Some variants are premised on the discovery of a surprisingly simple process for converting lignocellulosic biomass to nanocellulose or nanolignocelluloses. The biomass may be steam or hot water soaked to dissolve the hemicellulose. This step is followed by mechanical refining of the cellulose-rich (and lignin-rich) solids.

Some variations provide a nano-lignocellulosic composition comprising, on a dry-out, ash-free and acetyl-free basis: about 35 wt% to about 80 wt% of cellulose nano-fibrils, cellulose microfibrils, or a combination thereof; about 15 wt% to about 45 wt% lignin; and about 5 wt% to about 20 wt% hemicellulose.

In various embodiments, the nano-lignocellulosic composition may comprise about (or at least about, or at most about) 30 wt%, 35 wt%, 40 wt%, 45 wt%, 50 wt%, 55 wt%, 60 wt%, 65 wt%, 75 wt%, 80 wt%, 85 wt%, or 90 wt% of cellulose nano-fibrils, cellulose micro-fibrils, or a combination thereof, on a dry, ash-free, and acetyl-free basis.

In various embodiments, the nano-lignocellulosic composition may comprise about (or at least about, or at most about) 10 wt%, 15 wt%, 20 wt%, 25 wt%, 30 wt%, 35 wt%, 40 wt%, 45 wt%, or 50 wt% lignin on a dry, ash-free and acetyl-free basis.

In various embodiments, the nano-lignocellulosic composition may comprise about (or at least about, or at most about) 2, 3, 4,5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20 wt% hemicellulose on a dry, ash-free and acetyl-free basis. Hemicellulose may contain xylan or mannan as a main component.

"dry-out, ash-free and acetyl-free basis" means that the recited concentration (i) is absolutely free of any water, e.g., H-OH groups chemically contained in the sugar polymer are excluded; (ii) free of any ash, including loose ash (e.g., sand or dirt) and bound ash (e.g., metal oxides that are not readily extractable from the solids); and (iii) free acetic acid free of acetyl groups bound to the hemicellulose component, or derived from acetyl groups.

In certain embodiments, the composition comprises about 40 wt% to about 70 wt% cellulose nano-fibrils, cellulose microfibrils, or a combination thereof on a dry-out, ash-free, and acetyl-free basis.

In certain embodiments, the composition comprises from about 7 wt% to about 15 wt% hemicellulose on a dry, ash free and acetyl free basis.

The nano-lignocellulosic composition may contain water as moisture or in a slurry of solids. The nanolignocelluloses composition can contain at least about (or at least about, or at most about) 5 wt%, 10 wt%, 15 wt%, 20 wt%, 25 wt%, 30 wt%, 35 wt%, 40 wt%, 45 wt%, 50 wt%, 60 wt%, 70 wt%, 80 wt%, 90 wt% or more water on an ash-free and acetyl-free basis (but on a wet basis).

The nano-lignocellulosic composition may contain ash. The nanolignocelluloses composition, on a dry to and acetyl free basis, can contain at least about (or at least about, or at most about) 0.1 wt%, 0.5 wt%, 1 wt%, 2 wt%, 3 wt%, 4 wt%, 5 wt% or more ash.

The nano-lignocellulosic composition may contain acetyl groups. The nanolignocelluloses composition, on a dry to and ash free basis, can contain at least about (or at least about, or at most about) 0.1 wt%, 0.5 wt%, 1.0 wt%, 1.5 wt%, 2.0 wt%, 2.5 wt%, 3.0 wt% or more acetyl groups.

In certain variations, paper mills co-produce nano-ligno-cellulose and add this material back to their own supply as a means for making stronger paper, or smoother paper, or to provide a cheaper supply for the final paper product. In some embodiments, the nano-ligno-cellulose is produced as a side-stream operation of the paper mill or a nearby paper mill, using existing low-compatibility refiners. At least some of the resulting nano-ligno-cellulose is added back to the admixture.

This concept can lead to the ability to produce pulp using low cost wood as the primary raw material. Many paper mills use mixtures of hardwood and softwood to achieve the desired combination of strength and sheet formation/smoothness. In addition to replacing the more costly raw material, the nano-ligno-cellulose may also act as a retention aid for the paper machine. Thus, the paper machine can utilize the function of retention aids as well as the paper strength from the same material (nano-ligno-cellulose).

The principles of the present invention may be applied to any type of pulp or pulp mill, including chemical (e.g.,

cow leather, or sulfites), mechanical, thermomechanical, chemithermomechanical, hydrothermal mechanical (e.g.

Or GP3+^TM) Or other types of pulping. Chemical pulping generally degrades lignin and hemicellulose into small water soluble molecules that can be washed off cellulose fibers without depolymerizing the cellulose fibers.

Pulping removes lignin and hemicellulose without significant degradation of sugars, so that all major components (cellulose, hemicellulose and lignin) can be recovered. Various mechanical pulping processes, such as wood grinding and refiner mechanical pulping, physically tear the cellulose fibers apart from each other. Much of the lignin remains attached to the fibers. Strength is compromised because fibers may be cut. Related hybrid pulping processes use a combination of chemical and thermal treatments to begin a simplified chemical pulping process, followed by mechanical treatment to separate the fibers. These mixing methods include thermomechanical pulping and chemithermomechanical pulping. Chemical and thermal treatments reduce the amount of energy subsequently required for mechanical treatment and also reduce the amount of strength loss experienced by the fibers.

In some preferred embodiments, the present invention is applied to a thermomechanical or a hydrothermal mechanical pulp mill.

In some embodiments, some of the thermomechanical or hydrothermal mechanical pulp produced by the normal pulping operation is sent to a side-stream nanocellulose production operation (including mechanical refining of the thermomechanical or hydrothermal mechanical pulp) to produce nanocellulose particles (e.g., cellulose nanofibrils). Commonly owned U.S. patent application No.15/278,800, entitled "method FOR PRODUCING NANOCELLULOSE AND NANOCELLULOSE compositions produced thereby," filed on 28/9/2016, the teachings of which in some embodiments convert thermomechanical or hydrothermal mechanical pulp into NANOCELLULOSE, is incorporated herein by reference.

In some variations, nanocellulose may be added to the corrugated medium pulp with insufficient strength properties to allow the resulting composite to meet or exceed the strength properties required for the intended application. Although the principles of these embodiments are not limited to any particular source of corrugated medium or nanocellulose, preferred embodiments will extract by steam or hot water (referred to as steam or hot water extraction)

Technology) and the fractionation of an acidic solvent from biomass (known as acid solvent fractionation from biomass)Technology) the obtained slurry is refined to produce nanocellulose.

In some preferred embodiments, steam extraction or hot water extraction of the starting biomass is employed to produce a slurry, which is then refined and optionally washed to produce a corrugated medium pulp. Reference is made to commonly owned U.S. patent application No.14/044,784 filed 2013, 10, month 2 (published as US 20140096922a1, 4, month 10 2014), which is herein incorporated by reference for exemplary process conditions for producing corrugated medium pulp in various embodiments.

In some embodiments, the starting biomass is extracted with hot water to produce a slurry, which is then refined to produce nano-lignocelluloses. As meant herein, a "nano lignocellulose" is a material containing cellulose particles that are tightly bound (i.e., chemically and/or physically bound) to a large amount of lignin and hemicellulose. The cellulose (within the nano-lignocellulosic particles) may comprise nano-fibrils and/or micro-fibrils. The percentage of lignin (within the nano lignocellulose particles) is typically at least about 20 wt% and the percentage of hemicellulose (within the nano lignocellulose particles) is typically at least about 5 wt%. Certain embodiments employ hot water digestion and/or refining as described in commonly owned U.S. patent application No.15/047,608 (published as US20160244788 on 25/8/2016), which is incorporated herein by reference.

Effective hot water extraction conditions may include contacting the lignocellulosic biomass with steam (in saturated, superheated, or supersaturated form at various pressures) and/or hot water. In some embodiments, the HWE step is performed using liquid hot water at a temperature of about 140 ℃ and 220 ℃, e.g., about 150 ℃, 160 ℃, 170 ℃, 175 ℃, 180 ℃, 185 ℃, 190 ℃,200 ℃, or 210 ℃. In some embodiments, the HWE step is performed using liquid hot water for a residence time of about 1 minute to about 60 minutes, e.g., about 2 minutes, 2.5 minutes, 3 minutes, 3.5 minutes, 4 minutes, 5 minutes, 7.5 minutes, 10 minutes, 12.5 minutes, 15 minutes, 20 minutes, 25 minutes, 30 minutes, 35 minutes, 40 minutes, 45 minutes, 50 minutes, or 55 minutes.

In certain embodiments, lignin-coated nanocellulose (preferably lignin-coated cellulose nanofibrils) is added to the corrugated medium pulp. Without being limited by theory, the lignin in the nano-fibrils may enhance the moisture resistance of the corrugated medium paper. The production of lignin-coated nanocellulose is described in detail below. In some embodiments, the lignin fills the voids between the fibers during pressing.

Corrugated medium products can be produced from the modified (with nanocellulose) corrugated medium pulp using well-known techniques. See, for example, Tweede and Selke, "cars, crops and managed boards: handbook of paper and wood packaging technology," DEStech Publications, pages 41-56,2005; and Foster "Boxes, Corrugated", in The Wiley Encyclopedia of Packaging Technology (1997, edited by Brody A and Marsh K, second edition).

As meant herein, "nanocellulose" is broadly defined to include a range of cellulosic materials, including but not limited to microfibrillated cellulose (or cellulose microfibrils), nanofibrillated cellulose (or cellulose nanofibrils), microcrystalline cellulose, nanocrystalline cellulose, and micronized or fibrillated dissolving pulp. Typically, nanocellulose as provided herein will comprise particles having a length dimension (e.g., diameter) of at least one nanometer scale.

"Nanoflibrillated cellulose" or equivalent "cellulose nanofibrils" refers to cellulose fibers or regions containing particles or fibers on a nanoscale, or both micron-scale and nanoscale. "nanocrystalline cellulose" or equivalent "cellulose nanocrystals" refers to cellulose particles, regions, or crystals containing nanoscale domains, or both microscale and nanoscale domains. "micron-sized" includes 1 μm to 100 μm, while "nanoscale" includes 0.01nm to 1000nm (1 μm). Larger domains (including long fibers) may also be present in these materials.

Certain exemplary embodiments of the invention will now be described. These embodiments are not intended to limit the scope of the invention as claimed. The order of the steps may be varied, some steps may be omitted, and/or other steps may be added. References herein to a first step, a second step, etc. are for the purpose of illustrating some embodiments only.

Some variations provide a pulp product comprising cellulose and nano-lignocellulose, wherein the nano-cellulose comprises cellulose nano-fibrils and/or cellulose nanocrystals, and wherein the nano-lignocellulose is derived from cellulose in a step separate from the pulping process for producing cellulose.

In some embodiments, the pulping process is thermomechanical pulping or hydrothermal mechanical pulping. The pulp product may be paper or a structural object other than paper (e.g., boxes, boards, engineered wood, etc.).

In a preferred embodiment, the pulp product is stronger than an otherwise identical pulp product without the nano-ligno-cellulose. In some embodiments, the pulp product is smoother than an otherwise identical pulp product without the nano-lignocellulose.

The pulping process is in certain embodiments thermomechanical pulping, and the nano lignocellulose consists essentially of nano fibrils comprising cellulose, lignin, and hemicellulose. Nano-fibrils can be produced by mechanical refining of cellulose precursors (with significant amounts of lignin and hemicellulose) from thermomechanical pulping.

Other variations provide a corrugated medium pulp composition comprising a cellulose pulp and a nano-lignocellulose, wherein the nano-lignocellulose comprises hydrophobic nano-fibrils. In some embodiments, the nano-lignocelluloses is present at a concentration of at least about 0.1 wt%, 0.5 wt%, 1 wt%, 2 wt%, 5 wt%, or 10 wt% of the composition on a dry basis. In certain embodiments, the nano-ligno-cellulose is a significant portion of the slurry feed, i.e., about 5 wt%, 10 wt%, 15 wt%, 20 wt%, 25 wt%, or more.

In some embodiments of the corrugated medium pulp composition, the cellulosic pulp is a mechanical or thermomechanical pulp (e.g.,slurry). In some embodiments, the cellulose pulp is a chemical pulp (e.g.,

pulp, kraft pulp, sulfite pulp, or soda pulp).

In some embodiments, the method further comprises producing a corrugated medium product from the corrugated medium pulp composition. The first amount of lignocellulosic biomass and the second amount of lignocellulosic biomass may be from the same biomass source or different biomass sources.

In some embodiments, the nano-lignocelluloses is a lignin-containing hydrophobic cellulose. In these or other embodiments, the nano-lignocellulose is predominantly in the form of nano-fibrils, micro-fibrils, or a mixture thereof.

In some embodiments, a system for performing the disclosed methods is provided. The system may include a first subsystem for producing a first slurry at a first location and a second subsystem for producing nano-ligno-cellulose at a second location different from the first location. The production of the end product may be performed at one of the first subsystem or the second subsystem or at another location.

In some embodiments, the nano-lignocelluloses are derived from a biomass source selected from the group consisting of hardwood, softwood, agricultural waste, and combinations thereof.

In some embodiments, the nano-ligno-cellulose is obtained by: producing a cellulose-rich solid and liquid phase by fractionating biomass in the presence of an acid, a solvent for lignin, and water; the cellulose-rich solids are then mechanically refined to produce nano-ligno-cellulose. In certain embodiments, the acid is sulfur dioxide and the solvent is ethanol. In some embodiments, use is made of

The method produces nano-lignocelluloses for reinforcing cellulose fibers.

"enhancement" may be achieved in various embodiments by simple mixing, milling, grinding, stirring, sedimentation/drying, or other treatment.

In some embodiments, the method further comprises producing a single fiber product from the cellulosic fiber. In these or other embodiments, the method further comprises producing the composite material from the cellulosic fiber. Reinforcing the microfibers with nano-ligno-cellulose can increase the strength of composites and single fiber products, as well as other products.

In some embodiments, the product is first made from cellulose fibers and then the product (not a slurry) is reinforced with nano-lignocelluloses. In these embodiments, the reinforcement can be provided, for example, to the entire product or to selected surfaces or areas, if desired.

The biomass feedstock may be selected from hardwood, softwood, forest residues, eucalyptus, industrial waste, pulp and paper waste, consumer waste, or combinations thereof. Some embodiments utilize agricultural wastes including lignocellulosic biomass associated with food crops, annual grasses, energy crops, or other annually renewable feedstocks. Exemplary agricultural wastes include, but are not limited to, corn stover, corn fiber, wheat straw, sugar cane bagasse, sugar cane straw, rice straw, oat straw, barley straw, miscanthus, energy sugar cane straw/bagasse, or combinations thereof. The processes disclosed herein benefit from feedstock flexibility; it is effective for various cellulose-containing raw materials.

As used herein, "lignocellulosic biomass" refers to any material containing cellulose, lignin, and hemicellulose. Mixtures of one or more types of biomass may be used. In some embodiments, the biomass feedstock comprises a lignocellulosic component (e.g., the above described lignocelluloses) in addition to a sucrose-containing component (e.g., sugar cane or energy cane) and/or a starch component (e.g., corn, wheat, rice, etc.). Various moisture levels may be associated with the starting biomass. The biomass feedstock need not be, but may be, relatively dry. Generally, the biomass is in the form of particles or chips, but the particle size is not critical in the present invention.

In some embodiments, the total mechanical energy processed is less than about 5000 kilowatt-hours per ton of cellulose-rich solids, such as less than about 4000 kilowatt-hours per ton of cellulose-rich solids, 3000 kilowatt-hours per ton of cellulose-rich solids, 2000 kilowatt-hours per ton of cellulose-rich solids, or 1000 kilowatt-hours per ton of cellulose-rich solids. Energy consumption may be measured in any other suitable unit. An ammeter that measures the current drawn by the motor driving the mechanical processing device is one way to obtain an estimate of the total mechanical energy.

Mechanical treatment may use one or more known techniques such as, but in no way limited to, grinding, milling, beating, sonication, or any other means to form or release nanofibrillar fibers and/or nanocrystals in the cellulose. Essentially, any type of mill or apparatus that physically separates the fibers into the raw fibers may be utilized. Such mills are well known in the industry and include, but are not limited to, Valley beaters, single disc refiners, double disc refiners, conical refiners including both large and small angle, cylindrical refiners, homogenizers, microfluidizers, and other similar grinding or attrition devices. See, e.g., Smook, Handbook for Pulp & Paper technologies, Tappi press, 1992; and Hubbe et al, "Cellulose Nanocomposites: A Review," BioResources 3(3), 929-.

The extent of mechanical treatment can be monitored during the process by any of a number of means. Some optical instruments can provide continuous data on fiber length distribution and% fineness, either of which can be used to define the endpoint of the mechanical processing step. The time, temperature and pressure during mechanical processing may vary. For example, in some embodiments, sonication at ambient temperature and pressure may be utilized for a period of about 5 minutes to 2 hours.

In some embodiments, a portion of the cellulose-rich solids are converted to nano-fibrils, while the remaining cellulose-rich solids are not fibrillated. In various embodiments, about 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 95%, 99%, or substantially all of the cellulose-rich solid is fibrillated into nano-fibrils. In some embodiments, a portion of the nanofibrils are converted into nanocrystals, while the remaining nanofibrils are not converted into nanocrystals. During drying, some of the nanocrystals may revert together and form nano-fibrils.

After mechanical treatment, the nanocellulose material may be classified by particle size. A portion of the material may be subjected to a separation process, such as enzymatic hydrolysis, to produce glucose. Such materials may have, for example, good crystallinity, but may not have the desired particle size or degree of polymerization.

The method may further comprise treating the cellulose-rich solids with one or more enzymes or one or more acids. When acids are used, they may be selected from the group consisting of sulfur dioxide, sulfurous acid, lignosulfonic acid, acetic acid, formic acid, and combinations thereof. Hemicellulose-related acids, such as acetic acid or uronic acid, can be used alone or in combination with other acids. Additionally, the method may include treating the cellulose-rich solids with heat. In some embodiments, the method does not use any enzymes or acids.

When an acid is used, the acid may be a strong acid, such as sulfuric acid, nitric acid, or phosphoric acid. At more stringent temperatures and/or times, weaker acids may be used. Enzymes that hydrolyze cellulose (i.e., cellulases) and possibly hemicellulose (i.e., having hemicellulase activity) may be used in place of the acid or may be used in a sequential configuration before or after acidic hydrolysis.

In some embodiments, the method comprises enzymatically treating the cellulose-rich solids to hydrolyze amorphous cellulose. In other embodiments, or sequentially before or after the enzymatic treatment, the method may comprise acid treatment of the cellulose-rich solids to hydrolyze the amorphous cellulose.

In some embodiments, the method further comprises enzymatically treating the crystalline cellulose. In other embodiments, or sequentially before or after the enzymatic treatment, the method further comprises acid treating the crystalline cellulose.

If desired, an enzymatic treatment may be employed prior to or possibly in conjunction with the mechanical treatment. However, in a preferred embodiment, it is not necessary to perform an enzymatic treatment to hydrolyze the amorphous cellulose or weaken the structure of the fiber walls prior to separating the nanofibers.

After mechanical treatment, the nano-ligno-cellulose may be recovered. The separation of cellulose nanofibrillar fibers and/or nanocrystals may be accomplished using a device capable of disintegrating the ultrastructure of the cell wall while maintaining the integrity of the nanofibrils. For example, a homogenizer may be used. In some embodiments, cellulose aggregate fibrils are recovered whose component fibrils have widths in the range of 1-100nm, where the fibrils have not yet been completely separated from each other.

In some embodiments, the nano-lignocellulosic material is characterized by an average length-to-width aspect ratio of the particles of about 10 to about 1000, such as about 15, 20, 25, 35, 50, 75, 100, 150, 200, 250, 300, 400, or 500. Nano-fibrils generally involve higher aspect ratios than nanocrystals. For example, the nanocrystals can have a length range of about 100nm to 500nm and a diameter of about 1nm to 10 nm. The nano-fibrils have a length of about 2000nm and a diameter in the range of 5nm to 50nm, converted to an aspect ratio of 40 to 400. In some embodiments, the aspect ratio is less than 50, less than 45, less than 40, less than 35, less than 30, less than 25, less than 20, less than 15, or less than 10.

Optionally, the method further comprises hydrolyzing the amorphous cellulose to glucose, recovering the glucose, and fermenting the glucose into a fermentation product. Optionally, the method further comprises recovering, fermenting, or further processing hemicellulose sugars derived from some of the hemicellulose. Optionally, the method further comprises recovering, combusting or further treating the lignin.

Glucose formed from hydrolyzed amorphous cellulose may be integrated into the overall process to produce ethanol or other fermentation co-products. Thus, in some embodiments, the method further comprises hydrolyzing the amorphous cellulose to glucose, and recovering the glucose. The glucose may be purified and sold. Alternatively, glucose can be fermented to a fermentation product, such as, but not limited to, ethanol. If desired, the glucose or fermentation product can be recycled to the front end, e.g., for hemicellulose sugar processing.

When the hemicellulose sugars are recovered and fermented, they may be fermented to produce monomers or precursors thereof. The monomers can be polymerized to produce a polymer, which can then be combined with the nanocellulose material to form a polymer-nanocellulose composite.

In some embodiments, the method further comprises chemically converting the nano-lignocellulosic material into one or more nano-lignocellulosic derivatives. For example, the nano-lignocellulose derivative may be selected from the group consisting of nano-lignocellulose esters, nano-lignocellulose ethers, nano-lignocellulose ether esters, alkylated nano-lignocellulose compounds, cross-linked nano-lignocellulose compounds, acid-functionalized nano-lignocellulose compounds, base-functionalized nano-lignocellulose compounds, and combinations thereof.

Various types of nano-lignocellulose functionalization or derivatization may be employed, such as functionalization using polymers, chemical surface modification, functionalization using nanoparticles (i.e., other nanoparticles than nano-lignocellulose), modification with inorganic substances or surfactants, or biochemical modification.

High loadings of lignin have been achieved in thermoplastics. Higher loading levels are obtained with known lignin modifications. The preparation of useful polymeric materials containing substantial amounts of lignin has been the subject of research for over thirty years. Typically, lignin can be blended by extrusion into polyolefins or polyesters up to 25-40 wt% while satisfying mechanical properties. In order to increase the compatibility between lignin and other hydrophobic polymers, different approaches have been used. Chemical modification of lignin can be accomplished, for example, by esterification with long chain fatty acids.

An important factor limiting the use of strength-enhancing light weight nanocellulose in composite materials is the inherent hydrophilicity of cellulose. Surface modification of nanocellulose surfaces to impart hydrophobicity to enable uniform dispersion in hydrophobic polymer matrices is an active area of research. It has been found that the nano lignocelluloses as provided herein are hydrophobic.

Optionally, the method for producing a hydrophobic nano-lignocellulosic material may further comprise chemically modifying the lignin to increase the hydrophobicity of the nano-lignocellulosic material. Any known chemical modification of lignin may be performed to further increase the hydrophobic properties of the nano-lignocellulosic materials provided by embodiments of the present invention.

Some variants of the invention presuppose a relatively simple method for generating high-viscosity compounds made from cellulosic biomass. The high viscosity compounds will act as rheology modifiers when mixed in small proportions with different fluids such as drilling fluids, coatings and the like.

These compositions may act as gelling agents in hydraulic fracturing fluid formulations, particularly water-based formulations but equally for oil-based formulations. Ease of mixing and handling allows customization for individual reservoir properties. The various properties of these rheology modifiers provide a powerful advantage when compared to products currently available on the market. Some of these properties are higher thermal stability, strong shear thinning, thixotropic quality and water solubility. Another important property of these new compounds is that they are biodegradable and that their production does not involve any other chemicals than biomass and water.

Some variations provide a method for producing a nanocellulose material, the method comprising:

(a) providing a lignocellulosic biomass feedstock;

(d) mechanically treating the cellulose-rich solids to form a nanocellulose material containing cellulose nanofibrils and/or cellulose nanocrystals; and

(e) recovering the nanocellulose material.

The method may further comprise treating the cellulose-rich solids with one or more enzymes (e.g., cellulase enzymes) or with one or more acids such as sulfur dioxide, sulfurous acid, lignosulfonic acid, acetic acid, formic acid, or combinations thereof. The method may further comprise treating the cellulose-rich solids with heat. In some embodiments, steps (b) - (d) are performed without any enzyme or added acid.

The nano-cellulose material may comprise cellulose nano-fibrils or a mixture of cellulose nano-fibrils and cellulose nanocrystals. Fig. 1A-1C show SEM images of exemplary nanocellulose experimentally produced by refining and homogenizing materials produced by hot water extraction of biomass. The nanocellulose material may also comprise lignin, comprising lignin particles less than 1 micron in diameter. The method may include post-production bleaching of cellulose-rich solids and/or bleaching of nanocellulose material.

In some embodiments, the method further comprises recovering, fermenting, or further processing hemicellulose sugars derived from the hemicellulose oligomers. For example, the hemicellulose sugars may be fermented to a fermentation product, such as (but not limited to) ethanol.

In some embodiments, the method further comprises hydrolyzing a portion of the cellulose-rich solids to glucose; recovering the glucose; and optionally fermenting glucose to a fermentation product, such as n-butanol or 1, 4-butanediol.

The method may further comprise recovering, combusting or further treating the lignin washed from the cellulose-rich solids. Some or all of the initial lignin (in the starting material) may become part of the nanocellulose material, which will be at least partially hydrophobic due to the presence of lignin.

In some embodiments, the method further comprises chemically converting the nanocellulose material into one or more nanocellulose derivatives. For example, the nanocellulose derivative may be selected from the group consisting of nanocellulose esters, nanocellulose ethers, nanocellulose ether esters, alkylated nanocellulose compounds, crosslinked nanocellulose compounds, acid-functionalized nanocellulose compounds, base-functionalized nanocellulose compounds, and combinations thereof.

In certain embodiments, step (d) comprises a disc refining followed by homogenization of the cellulose-rich solids. Step (d) or a part thereof may be carried out at a solids consistency of at least 10 wt%, for example at least 20 wt%.

In some embodiments, the method comprises blasting (explode) cellulose fibers contained in the cellulose-rich solid. For example, the blasting of the fibers may be accomplished using steam explosion and/or rapid pressure reduction. In certain embodiments, step (d) utilizes a blow-line refiner, optionally under reduced pressure.

Some variations of the invention provide a method for producing a biomass-derived rheology modifier from cellulosic biomass, the method comprising:

(a) providing a feedstock comprising cellulosic biomass;

(c) refining the cellulose-rich solids in a first high intensity refining unit to produce refined cellulose solids;

(d) washing the refined cellulosic solids after step (c) and/or washing the digested stream prior to step (c) and then refining, thereby producing washed refined cellulosic solids;

(e) gelling the washed refined cellulose solids in a second high intensity refining unit, thereby producing gelled cellulose solids; and

(f) homogenizing the gelled cellulose solids in a high shear homogenizer to produce a biomass-derived rheology modifier comprising cellulose nanofibrils, cellulose nanocrystals, or a mixture of cellulose nanofibrils and cellulose nanocrystals.

Optionally, the method further comprises wet or dry cleaning the feedstock prior to step (b). Optionally, whether or not the feedstock is cleaned, the method further comprises reducing the size of the feedstock prior to step (b).

Step (b) may be carried out at a digestion temperature of about 140 ℃ to about 210 ℃. Step (b) may be conducted for a digestion time of about 5 minutes to about 45 minutes. Step (b) may be carried out at a liquid/solid weight ratio of about 2 to about 6.

The process may include, after step (b), performing a hot or cold spray depressurization of the digested stream.

The first high intensity polishing unit may utilize, for example, a disk or a tapered plate. In various embodiments, the first high intensity refining unit transfers energy to the cellulose-rich solids in an amount of about 20 kilowatts per ton to about 200 kilowatts per ton (on a dry basis).

The washing in step (d) may be carried out at a temperature of about 18 ℃ to about 95 ℃. In some embodiments, the washing in step (d) utilizes a pressurized screw press.

The second high intensity polishing unit may utilize, for example, a disk or a tapered plate. The first and second high intensity refining units preferably have different patterns with different groove and baffle (dam) sizes. In various embodiments, the second high intensity refining unit transfers energy to the washed refined cellulose solids in an amount from about 20 kilowatts/ton to about 200 kilowatts/ton (on a dry basis).

In some embodiments, the shear force delivered by the high shear homogenizer is equal to that generated at a pressure of from about 10,000psig to about 25,000 psig.

In some embodiments, the washed refined cellulose solids are stored for a period of time prior to step (e). Step (e) may be performed at a different location than steps (a) - (d). Also, step (f) may be performed at a different location from steps (a) - (e).

Other variations of the invention provide a method for producing a biomass-derived rheology modifier from cellulosic biomass, the method comprising:

(a) providing a pretreated feedstock comprising cellulose-rich solids;

(b) refining the cellulose-rich solids in a first high intensity refining unit to produce refined cellulose solids;

(c) optionally washing the refined cellulosic solids after step (b), and/or optionally washing the digested stream prior to step (b) and then refining, thereby producing washed refined cellulosic solids;

(d) gelling the washed refined cellulose solids in a second high intensity refining unit, thereby producing gelled cellulose solids; and

(e) homogenizing the gelled cellulose solids in a high shear homogenizer to produce a biomass-derived rheology modifier containing cellulose nano-fibrils.

In some embodiments, the pretreated feedstock is kraft pulp derived from wood or lignocellulosic biomass. In some embodiments, the pretreated feedstock is sulfite slurry derived from wood or lignocellulosic biomass. In some embodiments, the pretreated feedstock is a soda slurry derived from wood or lignocellulosic biomass. In some embodiments, the pretreated feedstock is a mechanical slurry derived from wood or lignocellulosic biomass. In some embodiments, the pretreated feedstock is a thermomechanical slurry derived from wood or lignocellulosic biomass. In some embodiments, the pretreated feedstock is a chemi-mechanical slurry derived from wood or lignocellulosic biomass.

A variation of the invention provides a water-based hydraulic fracturing fluid formulation or additive comprising (i) a nanocellulose material produced according to the method or (ii) a biomass-derived rheology modifier produced according to the method.

A variation of the invention provides an oil-based hydraulic fracturing fluid formulation or additive comprising (i) a nanocellulose material produced according to the method or (ii) a biomass-derived rheology modifier produced according to the method.

A variation of the invention provides a water-based drilling fluid formulation or additive comprising (i) a nanocellulose material produced according to the method or (ii) a biomass-derived rheology modifier produced according to the method.

A variation of the invention provides an oil-based drilling fluid formulation or additive comprising (i) a nanocellulose material produced according to said method or (ii) a biomass-derived rheology modifier produced according to said method.

Some variations provide a polymer-nanocellulose composite comprising (i) a nanocellulose material produced according to the method or (ii) a biomass-derived rheology modifier produced according to the method. Exemplary polymers include, but are not limited to, polylactide, poly (vinyl alcohol), polyethylene, polypropylene, and the like.

In some embodiments, the method produces high viscosity compounds having a size between 1 micron and 100 microns, such as between 15 microns and 50 microns. These new compounds without any chemicals (except biomass and water) can be used as rheology modifiers and are fully biodegradable due to the cellulose-based.

The method provides a number of advantages. The design allows the process to be fully integrated in one line from start-up with biomass until high viscosity compounds are produced. Or the method may be divided into modules, which may be located in different geographical locations.

The biomass feedstock can be selected from hardwood, softwood, forest residues, agricultural wastes (e.g., bagasse), industrial wastes, consumer wastes, or combinations thereof. In any of these methods, the feedstock can comprise sucrose. In some embodiments where sucrose is present in the feedstock, a majority of the sucrose is recovered as part of the fermentable sugars.

Some embodiments of the present invention enable processing of "agricultural wastes," which for present purposes is meant to include lignocellulosic biomass associated with food crops, annual grasses, energy crops, or other annually renewable feedstocks. Exemplary agricultural wastes include, but are not limited to, corn stover, corn fiber, wheat straw, bagasse, rice straw, oat straw, barley straw, miscanthus, energy cane, or combinations thereof. In certain embodiments, the agricultural waste is bagasse, energy bagasse, sugarcane straw, or energy sugarcane straw.

In some embodiments, the method further comprises wet or dry cleaning the feedstock prior to step (b). In some embodiments, the method further comprises reducing the size of the feedstock prior to step (b). The method may include size reduction, hot water soaking, dewatering, steaming, or other operations upstream of the digester.

Step (b) may be carried out at a digestion temperature of from about 140 ℃ to about 210 ℃, for example from about 175 ℃ to about 195 ℃. Step (b) may be carried out for a digestion time of from about 5 minutes to about 45 minutes, for example from about 15 minutes to about 30 minutes. Step (b) may be carried out at a liquid/solid weight ratio of from about 2 to about 6, for example about 3, 3.5, 4, 4.5 or 5.

In some embodiments, the reaction solution comprises steam in a saturated, superheated, or supersaturated form. In some embodiments, the reaction solution comprises hot water.

The pressure in the pressurized vessel can be adjusted to maintain the aqueous feed liquid as a liquid, vapor, or combination thereof. Exemplary pressures are from about 1atm (atmospheric) to about 30atm, such as about 3atm, 5atm, 10atm, or 15 atm.

The solids residence time of the digester (pressurized extraction vessel) can vary from about 2 minutes to about 4 hours, e.g., from about 5 minutes to about 1 hour. In certain embodiments, the residence time of the digester is controlled at about 5 to 15 minutes, such as 5 minutes, 6 minutes, 7 minutes, 8 minutes, 9 minutes, 10 minutes, 11 minutes, 12 minutes, 13 minutes, 14 minutes, or 15 minutes. The liquid phase residence time of the digester can vary from about 2 minutes to about 4 hours, for example from about 5 minutes to about 1 hour. The gas phase residence time of the digester can vary from about 1 minute to about 2 hours, for example from about 3 minutes to about 30 minutes. The solid phase residence time, liquid phase residence time, and gas phase residence time can all be about the same, or they can be independently controlled according to reactor engineering principles (e.g., recirculation and internal recirculation strategies).

In some embodiments, the process further comprises, after step (b), performing a thermal spray depressurization of the digested stream. Alternatively, cold-blow depressurization of the digested stream after step (b) may be employed.

To reduce the pressure, a blow tank may be placed between the digester and the polishing unit. In some embodiments, the vapor is separated from the blow tank and heat is recovered from at least some of the vapor. Optionally, at least some of the vapor is compressed and returned to the digester, and/or at least some of the vapor is purged from the process. Note that "blow tank" should be understood broadly to include not only a tank, but any other device or apparatus capable of allowing a pressure drop in a process stream. Thus, the blow tank (or blow mechanism) may be a tank, vessel, pipe section, valve, separation device, or other unit.

Each mechanical refiner may be selected from the group consisting of a hot blow refiner, a hot feed refiner, a disc refiner, a conical refiner, a cylindrical refiner, an in-line defibrator, a homogenizer, and combinations thereof. Mechanical treatment (refining) may employ one or more known techniques such as, but in no way limited to, milling, grinding, beating, sonication, or any other method of reducing the particle size of the cellulose. Such refiners are well known in the industry and include, but are not limited to, Valley beaters, single disc refiners, double disc refiners, conical refiners, including both large and small angles, cylindrical refiners, homogenizers, microfluidizers, and other similar grinding or attriting devices. See, for example, Smook, Handbook for Pulp & paper technologies, Tappi press, 1992.

Refining can be performed at a wide range of solids concentrations (consistencies), including consistencies of about 2% to about 50%, such as about 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 15%, 20%, 30%, 35%, or 40%.

Each mechanical refiner can be configured to deliver about 20 kilowatts/ton to about 200 kilowatts/ton (i.e., kilowatt refining power per ton of fiber based on the solid phase converted to the refining stream). In certain embodiments, the mechanical refiner is configured to deliver about 75 kilowatts of refining power per ton of fiber to about 150 kilowatts of refining power per ton of fiber. For example, a mechanical refiner with plates may be adjusted to achieve these power inputs by altering plate type, gap, speed, etc.

The extent of mechanical treatment can be monitored during the process by any of a number of means. Certain optical instruments can provide continuous data relating to fiber length distribution and% fineness, either of which can be used to define the end point of a mechanical processing step. The time, temperature and pressure during mechanical processing may vary. For example, in some embodiments, sonication at ambient temperature and pressure may be utilized for a period of about 5 minutes to 2 hours.

In some embodiments, a portion of the cellulose-rich solids are converted to fibrillate and/or gel while the remainder of the cellulose-rich solids are not fibrillated and/or gelled. In various embodiments, about 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 95%, 99%, or substantially all of the cellulose-rich solid is fibrillated and/or gelled.

The first high intensity polishing unit may utilize, for example, a disk or a tapered plate. In some embodiments, the first high intensity refining unit transfers energy to the cellulose-rich solids in an amount of about 20 kilowatts/ton to about 200 kilowatts/ton (on a dry basis), such as about 75 kilowatts/ton to about 150 kilowatts/ton (on a dry basis).

In some embodiments, the washing in step (d) may be performed at a temperature of about 18 ℃ to about 95 ℃, e.g., about 70 ℃ to about 80 ℃. The washing in step (d) may utilize a pressurized screw press.

In some embodiments, the second high intensity polishing unit utilizes a disk or conical plate. The first and second high intensity refining units preferably have different patterns with different groove and baffle sizes. In some embodiments, the second high intensity refining unit transfers energy to the washed refined cellulose solids in an amount from about 20 kilowatts/ton to about 200 kilowatts/ton (on a dry basis), for example from about 75 kilowatts/ton to about 150 kilowatts/ton (on a dry basis).

In some embodiments, the shear force delivered by the high shear homogenizer (or other unit operation capable of applying shear) is equivalent to that produced at a pressure of from about 1,000psig to about 50,000psig, e.g., from about 10,000psig to about 25,000 psig.

The washed purified cellulosic solids may be stored for a period of time prior to step (e), which may be carried out at a different location than steps (a) - (d). In some embodiments, step (f) is not performed at a location different from steps (a) - (e).

In some embodiments, the biomass-derived rheology-modifying agent can be characterized by a particle size (e.g., fiber or fibril length or effective length) of from about 1 micron to about 100 microns, such as from about 1 micron to about 50 microns. In certain embodiments, a majority (e.g., about 50%, 60%, 70%, 80%, 90%, or 95%) of the particles are in the size range of 10-15 microns. The rheology modifier derived from biomass can comprise particles (i.e., nanoparticles) of less than 5 microns, such as 4 microns, 3 microns, 2 microns, 1 micron, or less. The width of the particles may be less than 1 micron. Particles greater than 100 microns, such as 150 microns, 200 microns, 250 microns, 300 microns, 400 microns, 500 microns, or more, may be present.

In some embodiments, the rheology-modifying agent derived from biomass can be characterized by a particle size (e.g., length or effective length) of less than about 10 microns, such as about 9 microns, 8 microns, 7 microns, 6 microns, 5 microns, 4 microns, 3 microns, 2 microns, 1 micron or less. In certain embodiments, the nanocellulose particles are about 900nm, 800nm, 700nm, 600nm, 500nm, 400nm, 300nm, 200nm, 100nm, or less in length. In these or other embodiments (including lengths in excess of 1 micron), the nanocellulose particles may be from about 3nm to about 1000nm, for example from about 5nm to about 500nm, or from about 10nm to about 200nm, or about 5nm, 10nm, 15nm, 20nm, 25nm, 30nm, 40nm, 50nm, 60nm, 70nm, 80nm, 90nm, 100nm, 150nm, 200nm, 250nm, 300nm, 350nm, 400nm, or 450nm in diameter. In some of these embodiments, the nanoparticle (or a portion thereof) may be characterized as a nanocrystal.

The rheology modifier compound is primarily a cellulose-based polymer with some crystallite-shaped like nanocellulose in the structure containing some of the original biomass lignin. In some embodiments, the compounds are primarily hydrophilic in nature, providing greater stability to water-based drilling fluids and water-based fracturing fluids. In some embodiments having lignin content and suitable high intensity refining, the compound is hydrophobic, moderately hydrophobic, or a combination of hydrophilic and hydrophobic.

The present disclosure provides water-based hydraulic fracturing fluid formulations or additives comprising a biomass-derived rheology modifier produced according to the methods described herein.

The present disclosure provides oil-based hydraulic fracturing fluid formulations or additives comprising a biomass-derived rheology modifier produced according to the methods described herein.

The present disclosure provides water-based drilling fluid formulations or additives comprising a biomass-derived rheology modifier produced according to the methods described herein.

The present disclosure provides oil-based drilling fluid formulations or additives comprising a biomass-derived rheology modifier produced according to the methods described herein.

The process may further comprise removing one or more fermentation inhibitors (e.g. acetic acid or furfural) by stripping. The stripping may be carried out by treating the hydrolysed cellulose stream prior to fermentation. Alternatively, or additionally, the stream may be stripped after digestion, for example in a blow-down line.

In some embodiments, the method further comprises the step of fermenting fermentable sugars contained in the liquid phase from the initial digestion to a dilute fermentation product. The method may further comprise concentrating and purifying the fermentation product. The fermentation product may be selected from, for example, ethanol, n-butanol, 1, 4-butanediol, succinic acid, lactic acid, or combinations thereof. Furthermore, the solid stream containing lignin may be removed before or downstream of the fermentation.

The step may include conditioning the hydrolysate to remove some or most of the volatile acids and other fermentation inhibitors. Evaporation may include flashing or stripping to remove sulfur dioxide, if any, prior to removal of the volatile acid. The evaporation step is preferably carried out at an acetic acid dissociation pH of less than 4.8, most preferably the pH is selected from about 1 to about 2.5. In some embodiments, an additional evaporation step may be employed. These additional evaporation steps may be performed under different conditions (e.g., temperature, pressure, and pH) relative to the first evaporation step.

In some embodiments, some or all of the vaporized organic acid may be recycled to the first step (the digestion step) as a vapor or condensate to aid in the removal of hemicellulose or minerals from the biomass. The recycling of such organic acids, e.g. acetic acid, may be optimized along with process conditions, which may vary depending on the amount of recycling, to improve cooking effectiveness.

The step may include recovering fermentable sugars, which may be stored, transported or processed. The step may comprise fermenting the fermentable sugars into co-products (the primary product being the rheology modifier).

The steps may include preparing a solid residue (containing lignin) for combustion. This step may include refining, grinding, fluidizing, compacting and/or pelletizing the dried extracted biomass. The solid residue may be fed to the boiler in the form of a fine powder, loose fibers, granules, agglomerates, extrudates or any other suitable form. The solid residue can be extruded through a pressurized chamber using known equipment to form uniformly sized particles or agglomerates.

After fermentation, the residual solids (e.g., distillation residue) can be recovered, or burned as a solid or slurry, or recycled for incorporation into biomass particles. The use of fermentation residue solids may require further demineralization. Generally, any remaining solids are available for combustion after the distillation residue is concentrated.

Alternatively, or additionally, the process may include recovering residual solids as a fermentation co-product in the form of a solid, a liquid, or a slurry. The fermentation co-product may be used as a fertilizer or as a fertilizer ingredient as it will typically be rich in potassium, nitrogen and/or phosphorus.

The process may be continuous, semi-continuous or batch. When continuous or semi-continuous, the stripping column may be operated counter-currently, co-currently, or a combination thereof.

The process may further comprise bleaching the cellulose-rich solids prior to and/or as part of the refining step. Alternatively, or additionally, the method may further comprise bleaching the refined, gelled or homogenized material. Any known bleaching technique or sequence may be employed, including enzymatic bleaching.

Rheology modifiers as provided herein can be incorporated into drilling fluids, drilling fluid additives, fracturing fluids, and fracturing fluid additives. The rheology modifier can be present in various concentrations, for example, from about 0.001 wt% to about 10 wt% or more, such as about 0.01 wt%, 0.05 wt%, 0.1 wt%, 0.5 wt%, 1 wt%, or 2 wt%.

In some variations, the present invention relates to a group of cellulosic compounds that can be used in different applications. One of the applications is their use as product enhancers for drilling fluids. The rheology modifier may serve one or more functions in the drilling fluid. For example, rheology modifiers can generally act as gelling agents, or viscosifiers, that increase viscosity. Rheology modifiers may act as friction reducers. Also, the rheology modifier may be a drilling polymer, in place of or in addition to other polymers.

Drilling fluids are fluids used for drilling in the gas and oil industries, as well as other industries that use large drilling equipment. The drilling fluid is used for lubrication, providing hydrostatic pressure, keeping the drill bit cool, and keeping the borehole as free of cuttings as possible. The rheology modifiers provided herein are suitable as additives for these drilling fluids.

In some embodiments, enzymes may be used with the compositions as "breakers" to break down rheology modifiers after a period of time or under certain conditions (e.g., temperature or pH).

In some embodiments, lignosulfonates are incorporated to enhance lubricity in drilling applications. Additionally, the ability of lignosulfonates to reduce the viscosity of mineral slurries can be beneficial in petroleum drilling muds.

In some embodiments, a natural lignin or non-sulfonated lignin derivative is incorporated into the composition.

Some embodiments provide a drilling fluid additive comprising a rheology modifier.

Some embodiments provide a drilling fluid additive comprising a rheology modifier, wherein the additive further comprises a lignosulfonate.

Some embodiments provide a drilling fluid additive comprising a rheology modifier, wherein the additive further comprises a non-sulfonated lignin.

Some embodiments provide a drilling fluid additive comprising a rheology modifier, wherein the additive further comprises a crosslinker.

Some embodiments provide a drilling fluid additive comprising a crosslinked rheology modifier and a lignosulfonate.

Some embodiments provide drilling fluids comprising the disclosed drilling fluid additives. The drilling fluid may be a water-based drilling fluid, an oil-based drilling fluid, or a mixed water-based/oil-based drilling fluid.

In various embodiments, the drilling fluid further comprises one or more of the following: biomass-derived weighting materials, biomass-derived filtration control agents, biomass-derived rheology control agents, biomass-derived pH control agents, biomass-derived lost circulation materials, biomass-derived surface activity modifiers, biomass-derived lubricants, and biomass-derived flocculants, and/or biomass-derived stabilizers.

In some variations, the present disclosure provides a method of using a drilling fluid additive that includes combining the disclosed drilling fluid additive to a base fluid to generate a drilling fluid. In some variations, the present invention provides a method comprising introducing the disclosed drilling fluid additive directly or indirectly into a geological formation.

In some variations, the drilling method comprises introducing a drilling fluid additive directly or indirectly into the geological formation, wherein the drilling fluid additive comprises an enzyme that is degelled under conditions effective for the drilling. In a related variation, the drilling method includes introducing the drilling fluid additive directly or indirectly into the geological formation, followed by introducing an enzyme for degelatinization under effective conditions.

Some variations provide a method for producing a drilling fluid additive comprising refining biomass under effective pretreatment conditions and refining conditions to produce a drilling fluid additive as disclosed. In some embodiments, effective pretreatment conditions include the production of lignosulfonic acid. Optionally, at least a portion of the lignosulfonic acid is not removed and still present in the drilling fluid additive. In certain embodiments, the drilling fluid additive comprises the liquid slurry resulting from the process. For example, the slurry may contain a rheology modifier derived from biomass as well as water and pretreatment chemicals (e.g., acids, solvents, etc.).

Another application of these compositions is their use as product enhancers for hydraulic fracturing fluids. Improvements in this objective are due, inter alia, to their effects on reducing friction, improving the pumping of proppant at higher rates at reduced pressures, and predictable viscosity at high temperatures. Furthermore, these products are completely biodegradable; they are produced from biomass and are as non-biofouling as other products such as galactomannan derivatives.

The rheology modifier may be crosslinked to firmly gel in the fracturing fluid. In some embodiments, crosslinking of the rheology modifier results in a stronger gel with more hydration.

Ash derived from biomass (from biomass structures) or sand (from washing) can be used as proppant to replace mined silica.

In other variations, the present invention provides fracturing fluid additives.

Some embodiments provide a fracturing fluid additive comprising a rheology modifier.

Some embodiments provide a fracturing fluid additive comprising a rheology modifier, wherein the additive further comprises a lignosulfonate.

Some embodiments provide a fracturing fluid additive comprising a rheology modifier, wherein the additive further comprises a non-sulfonated lignin.

Some embodiments provide a fracturing fluid additive comprising a rheology modifier, wherein the additive further comprises a crosslinker.

Some embodiments provide a fracturing fluid additive comprising a crosslinking rheology modifier and a lignosulfonate.

Some embodiments provide fracturing fluids comprising the disclosed fracturing fluid additives. The fracturing fluid may be a water-based fracturing fluid, an oil-based fracturing fluid, or a mixed water-based/oil-based fracturing fluid.

In addition to the disclosed fracturing fluid additives, the fracturing fluid may also comprise one or more of the following: biomass-derived acids (e.g., acetic acid, formic acid, levulinic acid, and/or lignosulfonic acid), biomass-derived corrosion inhibitors (e.g., lignin or lignin derivatives), biomass-derived friction reducers (e.g., lignosulfonates or lignosulfonate derivatives), biomass-derived clay control agents, biomass-derived cross-linking agents, biomass-derived scale inhibitors, biomass-derived breakers, biomass-derived iron control agents, biomass-derived biocides (e.g., biomass hydrolysates), and/or a recycled or recovered water source derived from biorefineries. Typically, the fracturing fluid carries, contains, or is intended to be combined with a proppant, which may be a biomass-derived proppant (e.g., ash contained in the biomass structure and/or sand, ash, or dirt that collects with the biomass).

Some variations of the invention provide a method of using a fracturing fluid additive that includes incorporating the disclosed fracturing fluid additive into a base fluid to generate a fracturing fluid. Some methods include introducing a fracturing fluid additive directly or indirectly into the geological formation.

In some variations, a method for producing a fracturing fluid additive includes refining biomass under effective pretreatment conditions and refining conditions to produce the disclosed fracturing fluid additive. In some embodiments, the pretreatment conditions include the formation of lignosulfonic acid, which optionally is not completely removed and is present in the fracturing fluid additive. In some embodiments, the fracturing fluid additive comprises a liquid slurry resulting from the method. For example, the slurry may contain a rheology modifier derived from biomass as well as water and pretreatment chemicals (e.g., acids, solvents, etc.).

The rheology modifier of some embodiments is characterized by an average cellulose degree of polymerization of from about 100 to about 2000, for example from about 400 to about 1200 or from about 500 to about 800. In certain embodiments, the rheology modifier is free of enzymes.

The present disclosure is in no way limited to rheology modifiers. The material produced by the various refining steps (after biomass pretreatment) as disclosed can be used in a variety of applications. For example, the rheology modifier may be incorporated into a product selected from the group consisting of: structural objects, foams, aerogels, polymer composites, carbon composites, films, coatings, coating precursors, current or voltage carriers, filters, membranes, catalysts, catalyst substrates, coating additives, binder additives, cement additives, paper coatings, thickeners, rheology modifiers, drilling fluid additives, and combinations or derivatives thereof.

Some embodiments provide products for applications of sensors, catalysts, antimicrobial materials, current carrying capability, and energy storage capability. Cellulose crystals have the ability to assist in the synthesis of metal and semiconductor chains.

Some embodiments provide a composite material containing refined cellulose and a carbonaceous material, such as (but not limited to) lignin, graphite, graphene, or carbon aerogel.

Cellulose crystals can be combined with the stabilizing properties of surfactants and used to fabricate architectures of various semiconductor materials.

The reactive surface of the-OH side groups in the refined cellulose facilitates grafting of chemicals to achieve different surface properties. Surface functionalization allows tailoring of particle surface chemistry to promote self-assembly, controlled dispersion in a wide variety of matrix polymers, and control of particle-particle and particle-matrix bond strengths. The composite material may be transparent, have a greater tensile strength than cast iron, and have a very low coefficient of thermal expansion. Potential applications include, but are not limited to: barrier films, antimicrobial films, transparent films, flexible displays, reinforcing fillers for polymers, biomedical implants, drugs, drug delivery, fibers and textiles, templates for electronic components, separation membranes, batteries, supercapacitors, electroactive polymers, and many other applications.

Other applications suitable for the present invention include: a reinforcing polymer; a binder; high strength spun fibers and textiles; advanced composite materials; films for barrier and other properties; additives for coatings, paints, lacquers, adhesives; a switchable optical device; drug and drug delivery systems; bone replacement and tooth restoration; modifying the paper; packaging and construction products; additives for food and cosmetics; a catalyst; and a hydrogel.

Aeronautical and transportation composites may benefit from these rheology modifiers. Automotive applications include cellulosic composites with polypropylene, polyamides (e.g., nylon), or polyesters (e.g., PBT).

The rheology modifiers provided herein can be suitable as strength-enhancing additives for renewable and biodegradable composites. The fibril structure of cellulose can act as a binder between two organic phases, improving fracture toughness and preventing crack formation in packaging, building materials, appliances and renewable fiber applications.

The rheology modifiers provided herein can be used as transparent and dimensionally stable strength-enhancing additives and substrates in flexible display, flexible circuit, printable electronics, and flexible solar panel applications. For example, cellulose is incorporated into a substrate sheet formed by vacuum filtration, drying under pressure, and calendering. In the sheet-like structure, the cellulose acts as a glue between the filler aggregates. The resulting calendered sheet is smooth and flexible.

The rheology modifiers provided herein can be useful in composites and cement additives, allowing for reduced cracking and increased toughness and strength. The cellular cellulose-concrete hybrid material of the foam allows for a lightweight structure and increases crack reduction and strength.

Strength enhancement with cellulose increases both bond area and bond strength in paper and paperboard applications with high strength, high bulk, high filler content, and improved moisture and oxygen barrier properties. The pulp and paper industry is particularly benefited by the rheology modifiers provided herein.

Porous cellulose is useful in porous bioplastics, insulators and plastics as well as bioactive membranes and filters. Highly porous cellulosic materials are generally of high interest in the manufacture of filtration media and for biomedical applications, such as in dialysis membranes.

The rheology modifiers provided herein can be suitable as additives to improve the durability of coatings, protective coatings and varnishes to abrasion caused by ultraviolet radiation.

The rheology modifiers provided herein are suitable as thickeners in food and cosmetics. Rheology modifiers can be used as thixotropic, biodegradable, dimensionally stable thickeners (stable to temperature and salt addition). The rheology modifier materials provided herein may be suitable as Pickering stabilizers for emulsion and particle stabilized foams.

The large surface area of these rheology modifiers combined with their biodegradability make them attractive materials for highly porous, mechanically stable aerogels.

In some embodiments, the method comprises forming a structural object comprising a nano-lignocellulosic material or a derivative thereof.

In some embodiments, the method comprises forming a foam or aerogel comprising a nano-lignocellulosic material or derivative thereof.

In some embodiments, the method comprises combining a nano-lignocellulosic material or derivative thereof with one or more other materials to form a composite material. For example, the other material may include a polymer selected from polyolefins, polyesters, polyurethanes, polyamides, or combinations thereof. Alternatively, or in addition, the other materials may include carbon in various forms.

In some embodiments, the method comprises forming a film comprising a nano-lignocellulosic material or a derivative thereof. In certain embodiments, the film is optically transparent and flexible.

In some embodiments, the method comprises forming a coating or coating precursor comprising a nano-lignocellulosic material or derivative thereof. In some embodiments, the nanolignocelluloses-containing product is a paper coating.

In some embodiments, the nanolignocelluloses-containing product is configured as a catalyst, catalyst substrate, or co-catalyst. In some embodiments, the nanolignocelluloses-containing product is electrochemically configured to carry or store an electrical current or voltage.

In some embodiments, the nanolignocellulose-containing product is incorporated into a filter, membrane, or other separation device.

In some embodiments, the nanolignocelluloses-containing product is incorporated as an additive into a coating, paint, or adhesive. In some embodiments, the nano-lignocellulose-containing product is incorporated as a cement additive.

In some embodiments, the nano-lignocellulose-containing product is incorporated as a thickener or rheology modifier. For example, the nano-lignocellulose-containing product may be an additive in a drilling fluid, such as (but not limited to) a production fluid and/or gas fluid, or a fracturing fluid.

The nanolignocellulose-containing product can include any of the disclosed nanolignocellulose compositions. Many nanolignocellulose containing products are possible. For example, the nano-lignocellulose-containing product may be selected from the group consisting of: structural objects, foams, aerogels, polymer composites, carbon composites, films, coatings, coating precursors, current or voltage carriers, filters, membranes, catalysts, catalyst substrates, coating additives, binder additives, cement additives, paper coatings, thickeners, rheology modifiers, drilling fluid additives, and combinations or derivatives thereof.

For example, certain nanolignocellulose-containing products provide high clarity, good mechanical strength, and/or enhanced gas (e.g., O)₂Or CO₂) Barrier properties. For example, certain nanolicocellulose-containing products containing the hydrophobic nanocellulose materials provided herein can be used as moisture and ice resistant coatings.

Some embodiments provide a nano-lignocellulose-containing product suitable for use in sensors, catalysts, antimicrobial materials, current-carrying and energy storage capabilities.

Some embodiments provide a composite material comprising nano-lignocelluloses and a carbonaceous material, such as (but not limited to) lignin, carbon black, graphite, graphene, or carbon aerogel.

The reactive surface of the-OH side group in the nano lignocellulose facilitates grafting of chemicals to achieve different surface properties. Surface functionalization allows tailoring of particle surface chemistry to promote self-assembly, controlled dispersion within a wide variety of matrix polymers, and control of particle-particle and particle-matrix bond strengths. The composite material may be transparent, have a greater tensile strength than cast iron, and have a very low coefficient of thermal expansion. Potential applications include, but are not limited to: barrier films, antimicrobial films, transparent films, flexible displays, reinforcing fillers for polymers, biomedical implants, drugs, drug delivery, fibers and textiles, templates for electronic components, separation membranes, batteries, supercapacitors, electroactive polymers, and many other applications.

Other nano-lignocellulosic applications suitable for the present invention include: a reinforcing polymer; high strength spun fibers and textiles; advanced composite materials; films for barrier and other properties; additives for coatings, paints, lacquers and adhesives; a switchable optical device; drug and drug delivery systems; bone replacement and tooth restoration; modifying the paper; packaging and construction products; food and cosmetic additives; a catalyst; and a hydrogel.

Aerospace and automotive applications include nano-lignocellulosic composites with polypropylene, polyamides (e.g., nylon), or polyesters (e.g., PBT).

The nano lignocellulosic materials provided herein are suitable as strength-enhancing additives for renewable and biodegradable composites. The nanofibrillar structure of cellulose may act as a binder between two organic phases, improving fracture toughness and preventing crack formation in packaging, building materials, appliances and renewable fiber applications.

The nano-lignocellulosic materials provided herein are suitable as transparent and dimensionally stable strength-enhancing additives and substrates in the application of flexible displays, flexible circuits, printable electronics, and flexible solar panels. For example, nano-lignocelluloses is incorporated into a substrate sheet formed by vacuum filtration, drying under pressure, and calendering. In the lamellar structure, the nanocellulose acts as a glue between the filler aggregates. The resulting calendered sheet is smooth and flexible.

The nano-lignocellulosic materials provided herein are suitable for composites and cement additives, allowing for reduced cracking and increased toughness and strength. The foamed porous nano-lignocellulose-concrete hybrid material allows for a lightweight structure and increases crack reduction and strength.

Strength enhancement with nano-ligno-cellulose increases both bond area and bond strength in applications of high strength, high bulk, high filler content, and paper and paperboard with enhanced moisture and oxygen barrier properties. The pulp and paper industry is particularly benefited from the nano-lignocellulosic materials provided herein.

The nano-fibrillated cellulose nano-paper has higher density and higher tensile mechanical properties than conventional paper. It may also be optically transparent and flexible, with low thermal expansion and excellent oxygen barrier properties. The functionality of the nanopaper can be further broadened by the addition of other entities such as carbon nanotubes, nanoclays, or conductive polymer coatings.

Rojo et al, Comprehensive emulsification of the effect of the recognition of the physical, barrier, mechanical and surface properties of nanocellulosefilms, Green chem., 2015, 17, 1853-1866, herein incorporated by reference.

The porous nano lignocellulose can be used for porous biological plastics, insulators and plastics, and bioactive membranes and filters. Highly porous materials are generally of high interest in the manufacture of filtration media and for biomedical applications, for example in dialysis membranes.

The nano-lignocellulosic materials provided herein are suitable as coating materials with oxygen barrier and wood fiber affinity in food packaging and printing paper applications.

The nano-lignocellulosic materials provided herein are suitable as additives to improve the durability of coatings, protective coatings and varnishes to abrasion caused by ultraviolet radiation.

The nano-lignocellulosic materials provided herein are suitable as thickeners in food and cosmetics. The nano lignocellulose can be used as a thickening agent (stable to temperature and salt addition) with thixotropy, biodegradability and dimensional stability. The nano lignocellulosic materials provided herein are suitable as Pickering stabilizers for emulsion and particle stabilized foams.

The large surface area of these nano-lignocellulosic materials combined with their biodegradability make them attractive materials for highly porous, mechanically stable aerogels.

The invention also provides systems configured to perform the disclosed methods and compositions produced thereby. Any stream produced by the disclosed methods can be partially or fully recovered, purified or further processed, and/or sold.

In this detailed description, reference has been made to various embodiments of the invention and non-limiting examples relating to how the invention may be understood and practiced. Other embodiments may be utilized without departing from the spirit and scope of the present invention, which do not provide all of the features and advantages set forth herein. The present invention includes routine experimentation and optimization of the methods and systems described herein. Such modifications and variations are considered to be within the scope of the invention as defined by the appended claims.

All publications, patents, and patent applications cited in this specification are herein incorporated by reference in their entirety as if each individual publication, patent, or patent application were specifically and individually indicated to be incorporated herein by reference.

Where methods and steps described above indicate certain events occurring in a certain order, those of ordinary skill in the art will recognize that the order of certain steps may be modified and that such modifications are in accordance with the variations of the present invention. In addition, certain steps may be performed concurrently in a parallel process, as well as sequentially, where possible.

To the extent there are variations of the invention, which are within the spirit of the disclosure or equivalent to the inventions found in the dependent claims, it is intended that this patent will also cover such variations. The invention is limited only by the claims.

Examples

Example 1: nanohligocellulose produced from softwood

Softwood (pine) chips were processed in a pilot steam gun digester at 185 ℃ for 20 minutes to give a pulp yield of about 80%. The slurry was passed through a pilot plant disc refiner to defibrate the cooked wood chips to a freeness of about 100. The freeness of the slurry gives a measure of the rate of Drainage of the dilute slurry suspension (see TAPPI T221 "slurry Drainage Time of Pulp)"). The slurry was then passed through a laboratory scale homogenizer three times to achieve the target of 80-85% fines, thereby producing unwashed nano-ligno-cellulose. The percentage of fines (refined material) can be increased by more passes through the homogenizer. The unwashed nanolignocelluloses was washed with water at 60 ℃ 3 times for 30 minutes at about 2 kg water/kg pulp, 1 kg water/kg pulp, and 1 kg water/kg pulp to produce washed nanolignocellulose.

Fig. 2 shows a 40 x magnified optical micrograph of the washed nano-lignocellulose produced in this example.

The nano-lignocelluloses in this example is a combination of precipitated lignin particles (diameter of about 50 to 300 nanometers), lignocelluloses nano-fibrils (length of about 500 nanometers, width of about 10 to 500 nanometers, and length of tens of micrometers), and lignocelluloses fines (length <76 micrometers and width <5 micrometers).

The washed solids were analyzed for composition. The total carbohydrate is about 66.8 wt% of the solids. 54 wt% glucan, 9.2 wt% xylan, 1.3 wt% galactan, 0.6 wt% arabinan, and 1.7 wt% mannan. The concentration of acetyl groups in the solid was 1.9 wt%. The total lignin was 35.8 wt%, 33.3 wt% (as solids) of which was Klason lignin and 2.5 wt% (as solids) of which was acid soluble lignin.

The solution phase analysis showed 0.98 wt% glucose, 7.44 wt% xylose, 0.42 wt% galactose, 0.35 wt% arabinose, and 0.79 wt% mannose, all sugars as a percentage of the original total solids (as a percentage of wood). Formic acid 0.07 wt%, acetic acid 0.28 wt%, HMF 0.02 wt%, furfural 0.02 wt%, and dissolved lignin 1.82 wt%, all again as a percentage of the original total solids.

Example 2: nanohllocelluiose produced from hardwood

Hardwood chips were processed in a pilot steam gun digester at 185 ℃ for 15 minutes to give a pulp yield of about 80%. The slurry was passed through a pilot plant disc refiner to defibrate the cooked wood chips to a freeness of about 100. The slurry was then passed through a laboratory scale homogenizer three times to achieve the target of 80-85% fines, thereby producing unwashed nano-ligno-cellulose. The percentage of fines (refined material) can be increased by more passes through the homogenizer. The unwashed nanolignocelluloses was washed with water at 60 ℃ 3 times for 30 minutes at about 2 kg water/kg pulp, 1 kg water/kg pulp, and 1 kg water/kg pulp to produce washed nanolignocellulose.

Fig. 3 shows a 40 x magnified optical micrograph of the washed nano-lignocellulose produced in this example.

The slurry produced in this example was also passed through a homogenizer 7 times, producing 92% fines. This compares to bleached softwood kraft, which was massuko refined, 14 passes, and 93% fines by area. Fig. 4 is a graph of the filtration rate of the nano lignocellulose compared to a kraft pulp of the prior art. Filtration was a Buchner filtration at 0.8 wt% total solids with a starting volume of 450mL (based on 17% total solids in the nanocellulose pad, the total available filtrate assumed to be 430 mL). The filter paper was Whatman 4 (pore size 20-25 μm).

Figure 4 shows the higher filtration rate of the nano lignocellulose relative to bleached kraft fibrils. In particular, the nano-ligno-cellulose is substantially 100% complete in less than 100 minutes. Due to the high lignin content, the water retention and drainage rate of the nano lignocellulose fibrils is much higher than that of pure cellulose fibrils. This is believed to be a key performance attribute for the use of nano-lignocelluloses on paper machines.

Claims

1. A nano-lignocellulosic composition comprising, on a dry, ash-free and acetyl-free basis: about 35 wt% to about 80 wt% of cellulose nano-fibrils, cellulose microfibrils, or a combination thereof; about 15 wt% to about 45 wt% lignin; and about 5 wt% to about 20 wt% hemicellulose.

2. The nano-lignocellulosic composition according to claim 1, wherein the composition comprises about 40 to about 70 wt% of cellulose nano-fibrils, cellulose micro-fibrils, or a combination thereof, on a dry-out, ash-free, and acetyl-free basis.

3. The nano-lignocellulosic composition according to claim 1, wherein the composition comprises about 45 to about 60 wt% of cellulose nano-fibrils, cellulose micro-fibrils, or a combination thereof, on a dry-out, ash-free, and acetyl-free basis.

4. The nano-lignocellulosic composition of claim 1 wherein the composition comprises about 20 to about 40 wt% lignin on a dry-out, ash-free and acetyl-free basis.

5. The nano-lignocellulosic composition of claim 1 wherein the composition comprises about 25 to about 35 wt% lignin on a dry-out, ash-free and acetyl-free basis.

6. The nano-lignocellulosic composition according to claim 1, wherein the composition comprises about 7 to about 15 wt% hemicellulose, on a dry-out, ash-free and acetyl-free basis.

7. The nano-lignocellulosic composition according to claim 1, wherein the composition comprises about 8 to about 14 wt% hemicellulose, on a dry-out, ash-free and acetyl-free basis.

8. The nano-lignocellulosic composition according to claim 1, wherein the hemicellulose contains xylan as a main component.

9. The nano-lignocellulosic composition according to claim 1, wherein the hemicellulose contains mannan as a main component.

10. The nano-lignocellulosic composition according to claim 1, wherein the nano-lignocellulosic composition is characterized by: at least 99% filtration was completed in less than 100 minutes.

11. A pulp product or paper product containing the nano-lignocellulosic composition according to claim 1.