(19)
(11)EP 2 925 789 B1

(12)EUROPEAN PATENT SPECIFICATION

(45)Mention of the grant of the patent:
04.07.2018 Bulletin 2018/27

(21)Application number: 13859071.6

(22)Date of filing:  28.11.2013
(51)International Patent Classification (IPC): 
C08B 15/08(2006.01)
(86)International application number:
PCT/US2013/072441
(87)International publication number:
WO 2014/085729 (05.06.2014 Gazette  2014/23)

(54)

PROCESSES AND APPARATUS FOR PRODUCING NANOCELLULOSE, AND COMPOSITIONS AND PRODUCTS PRODUCED THEREFROM

VERFAHREN UND VORRICHTUNG ZUR HERSTELLUNG VON NANOCELLULOSE SOWIE DARAUS HERGESTELLTE ZUSAMMENSETZUNGEN UND PRODUKTE

PROCÉDÉS ET APPAREIL DE PRODUCTION DE NANOCELLULOSE ET COMPOSITIONS ET PRODUITS OBTENUS À PARTIR DE CELLE-CI


(84)Designated Contracting States:
AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR

(30)Priority: 30.11.2012 US 201261732047 P
25.06.2013 US 201361838985 P
29.10.2013 US 201361897156 P
27.11.2013 US 201314092906
27.11.2013 US 201314092908
27.11.2013 US 201314092910

(43)Date of publication of application:
07.10.2015 Bulletin 2015/41

(73)Proprietor: Api Intellectual Property Holdings, LLC
Atlanta, Georgia 30308 (US)

(72)Inventors:
  • NELSON, Kimberly
    Atlanta, Georgia 30317 (US)
  • RETSINA, Theodora
    Atlanta, Georgia 30308 (US)
  • PYLKKANEN, Vesa
    Atlanta, Georgia 30329 (US)
  • O'CONNOR, Ryan
    Minnetrista, Minnesota 55364 (US)

(74)Representative: Dehns 
St. Brides House 10 Salisbury Square
London EC4Y 8JD
London EC4Y 8JD (GB)


(56)References cited: : 
WO-A1-2011/001036
US-A1- 2011 003 352
US-A1- 2012 135 505
US-A1- 2010 288 456
US-A1- 2011 196 094
US-B1- 6 228 213
  
  • HARLIN ET AL.: 'Developments in advanced biocomposites.' VTT TECHNICAL RESEARCH CENTRE OF FINLAND ., [Online] 2010, pages 71 - 78, XP055260335 Retrieved from the Internet: <URL:http://www.vtt.fi/inf/pdf/tiedotteet/2 010/T2558.pdf> [retrieved on 2014-03-11]
  
Note: Within nine months from the publication of the mention of the grant of the European patent, any person may give notice to the European Patent Office of opposition to the European patent granted. Notice of opposition shall be filed in a written reasoned statement. It shall not be deemed to have been filed until the opposition fee has been paid. (Art. 99(1) European Patent Convention).


Description

FIELD



[0001] The present invention generally relates to nanocellulose and related materials produced by fractionating lignocellulosic biomass and further processing the cellulose fraction.

BACKGROUND



[0002] Biomass refining (or biorefining) has become more prevalent in industry. Cellulose fibers and sugars, hemicellulose sugars, lignin, syngas, and derivatives of these intermediates are being utilized for chemical and fuel production. Indeed, we now are observing the commercialization of integrated biorefineries that are capable of processing incoming biomass much the same as petroleum refineries now process crude oil. Underutilized lignocellulosic biomass feedstocks have the potential to be much cheaper than petroleum, on a carbon basis, as well as much better from an environmental life-cycle standpoint.

[0003] Lignocellulosic biomass is the most abundant renewable material on the planet and has long been recognized as a potential feedstock for producing chemicals, fuels, and materials. Lignocellulosic biomass normally comprises primarily cellulose, hemicellulose, and lignin. Cellulose and hemicellulose are natural polymers of sugars, and lignin is an aromatic/aliphatic hydrocarbon polymer reinforcing the entire biomass network. Some forms of biomass (e.g., recycled materials) do not contain hemicellulose.

[0004] Despite being the most available natural polymer on earth, it is only recently that cellulose has gained prominence as a nanostructured material, in the form of nanocrystalline cellulose (NCC), nanofibrillar cellulose (NFC), and bacterial cellulose (BC). Nanocellulose is being developed for use in a wide variety of applications such as polymer reinforcement, anti-microbial films, biodegradable food packaging, printing papers, pigments and inks, paper and board packaging, barrier films, adhesives, biocomposites, wound healing, pharmaceuticals and drug delivery, textiles, water-soluble polymers, construction materials, recyclable interior and structural components for the transportation industry, rheology modifiers, low-calorie food additives, cosmetics thickeners, pharmaceutical tablet binders, bioactive paper, pickering stabilizers for emulsion and particle stabilized foams, paint formulations, films for optical switching, and detergents. Despite the major advantages of nanocellulose such as its non-toxicity and great mechanical properties, its use to now has been in niche applications. Its moisture sensitivity, its incompatibility with oleophilic polymers, and the high energy consumption needed to produce, for example, NFC have so far prevented it from competing with other mass products such as ordinary paper or plastic. See "THE GLOBAL MARKET FOR NANOCELLULOSE TO 2017," FUTURE MARKETS INC. TECHNOLOGY REPORT No. 60, SECOND EDITION (October 2012).

[0005] Biomass-derived pulp may be converted to nanocellulose by mechanical processing. For instance, US 2012/0135505 describes a method for preparing microcrystalline cellulose comprising a prior step of compaction of the cellulose before degradation of the glucose chains. Although the process may be simple, disadvantages include high energy consumption, damage to fibers and particles due to intense mechanical treatment, and a broad distribution in fibril diameter and length.

[0006] Biomass-derived pulp may be converted to nanocellulose by chemical processing. For example, pulp may be treated with 2,2,6,6-tetramehylpiperidine-1-oxy radical (TEMPO) to produce nanocellulose. Such a technique reduces energy consumption compared to mechanical treatment and can produce more uniform particle sizes, but the process is not regarded as economically viable.

[0007] Improved processes for producing nanocellulose from biomass at reduced energy costs are needed in the art. Also, improved starting materials (i.e., biomass-derived pulps) are needed in the art for producing nanocellulose. It would be particularly desirable for new processes to possess feedstock flexibility and process flexibility to produce either or both nanofibrils and nanocrystals, as well as to co-produce sugars, lignin, and other co-products. For some applications, it is desirable to produce nanocellulose with high crystallinity, leading to good mechanical properties of the nanocellulose or composites containing the nanocellulose. For certain applications, is would be beneficial to increase the hydrophobicity of the nanocellulose.

SUMMARY



[0008] In some variations, the present invention provides a process for producing a nanocellulose material comprising nanocellulose particles having at least one length dimension of from 0.01nm to 1000nm, the process comprising:
  1. (a) providing a lignocellulosic biomass feedstock;
  2. (b) fractionating the feedstock in the presence of an acid, a solvent for lignin, and water, to generate cellulose-rich solids and a liquid containing hemicellulose and lignin;
  3. (c) mechanically treating the cellulose-rich solids with a total mechanical energy of less than about 1000 kilowatt-hours per ton (1.102 kWh/kg) of said cellulose-rich solids to form cellulose fibrils and/or cellulose crystals, thereby generating a nanocellulose material having a crystallinity of at least 60%; and
  4. (d) recovering the nanocellulose material.


[0009] In some embodiments, the acid is selected from the group consisting of sulfur dioxide, sulfurous acid, sulfur trioxide, sulfuric acid, lignosulfonic acid, and combinations thereof. In particular embodiments, the acid is sulfur dioxide.

[0010] In some embodiments, during step (c), the cellulose-rich solids are treated with a total mechanical energy of less than about 500 kilowatt-hours per ton (0.551 kWh/kg) of the cellulose-rich solids. In certain embodiments, the total mechanical energy is from about 100 kilowatt-hours (0.110 kWh/kg) to about 400 kilowatt-hours per ton (0.441 kWh/kg) of the cellulose-rich solids.

[0011] Step (c) may further comprise treatment of the cellulose-rich solids with one or more enzymes or with one or more acids. When acids are employed, they may be selected from the group consisting of sulfur dioxide, sulfurous acid, lignosulfonic acid, acetic acid, formic acid, and combinations thereof. Also, step (c) may include treatment of the cellulose-rich solids with heat. In some embodiments, step (c) does not employ any enzymes or acids.

[0012] In some embodiments, the crystallinity of the nanocellulose material is at least 70%, 75%, 80%, or 85% (or higher).

[0013] The process may further comprise bleaching the cellulose-rich solids prior to step (c) and/or as part of step (c). Alternatively, or additionally, the process may further comprise bleaching the nanocellulose material during step (c) and/or following step (c).

[0014] The nanocellulose material may include, or consist essentially of, nanofibrillated cellulose. The nanocellulose material may include, or consist essentially of, nanocrystalline cellulose. In some embodiments, the nanocellulose material may include, or consist essentially of, nanofibrillated cellulose and nanocrystalline cellulose.

[0015] In some embodiments, the nanocellulose material is characterized by an average degree of polymerization from about 100 to about 1500. For example, the nanocellulose material may be characterized by an average degree of polymerization from about 300 to about 700, or from about 150 to about 250.

[0016] Optionally, the process further comprises hydrolyzing amorphous cellulose into glucose in step (b) and/or step (c), recovering the glucose, and fermenting the glucose to a fermentation product. Optionally, the process further comprises recovering, fermenting, or further treating hemicellulosic sugars derived from the hemicellulose. Optionally, the process further comprises recovering, combusting, or further treating the lignin.

[0017] When hemicellulosic sugars are recovered and fermented, they may be fermented to produce a monomer or precursor thereof. The monomer may be polymerized to produce a polymer, which may then be combined with the nanocellulose material to form a polymer-nanocellulose composite.

[0018] In some embodiments, the nanocellulose material is at least partially hydrophobic via deposition of at least some of the lignin onto a surface of the cellulose-rich solids during step (b). In these or other embodiments, the nanocellulose material is at least partially hydrophobic via deposition of at least some of the lignin onto a surface of the nanocellulose material during step (c) or step (d).

[0019] In some embodiments, the process further comprises chemically converting the nanocellulose material to one or more nanocellulose derivatives. For example, nanocellulose derivatives may be selected from the group consisting of nanocellulose esters, nanocellulose ethers, nanocellulose ether esters, alkylated nanocellulose compounds, cross-linked nanocellulose compounds, acid-functionalized nanocellulose compounds, base-functionalized nanocellulose compounds, and combinations thereof.

[0020] Certain variations provide a process for producing a nanocellulose material comprising nanocellulose particles having at least one length dimension of from 0.01nm to 1000nm, the process comprising:
  1. (a) providing a lignocellulosic biomass feedstock;
  2. (b) fractionating the feedstock in the presence of sulfur dioxide, a solvent for lignin, and water, to generate cellulose-rich solids and a liquid containing hemicellulose oligomers and lignin, wherein the crystallinity of the cellulose-rich solids is at least 70%, wherein SO2 concentration is from about 10 wt% to about 50 wt%, fractionation temperature is from about 130°C to about 200°C, and fractionation time is from about 30 minutes to about 4 hours;
  3. (c) mechanically treating the cellulose-rich solids with a total mechanical energy of less than about 1000 kilowatt-hours per ton (1.102 kWh/kg) of said cellulose-rich solids to form cellulose fibrils and/or cellulose crystals, thereby generating a nanocellulose material having a crystallinity of at least 70%; and
  4. (d) recovering the nanocellulose material.


[0021] In some embodiments, the SO2 concentration is from about 12 wt% to about 30 wt%. In some embodiments, the fractionation temperature is from about 140°C to about 170°C. In some embodiments, the fractionation time is from about 1 hour to about 2 hours. The process may be controlled such that during step (b), a portion of the solubilized lignin intentionally deposits back onto a surface of the cellulose-rich solids, thereby rendering the cellulose-rich solids at least partially hydrophobic.

[0022] In some embodiments, the present invention provides a process for producing a hydrophobic nanocellulose material comprising nanocellulose particles having at least one length dimension of from 0.01nm to 1000nm, the process comprising:
  1. (a) providing a lignocellulosic biomass feedstock;
  2. (b) fractionating the feedstock in the presence of an acid, a solvent for lignin, and water, to generate cellulose-rich solids and a liquid containing hemicellulose and lignin, wherein a portion of the lignin deposits onto a surface of the cellulose-rich solids, thereby rendering the cellulose-rich solids at least partially hydrophobic;
  3. (c) mechanically treating the cellulose-rich solids with a total mechanical energy of less than about 1000 kilowatt-hours per ton (1.102 kWh/kg) of said cellulose-rich solids to form cellulose fibrils and/or cellulose crystals, thereby generating a hydrophobic nanocellulose material having a crystallinity of at least 60%; and
  4. (d) recovering the hydrophobic nanocellulose material.


[0023] In some embodiments, the acid is selected from the group consisting of sulfur dioxide, sulfurous acid, sulfur trioxide, sulfuric acid, lignosulfonic acid, and combinations thereof.

[0024] In some embodiments, during step (c), the cellulose-rich solids are treated with a total mechanical energy of less than about 500 kilowatt-hours per ton (0.551 kWh/kg) of the cellulose-rich solids.

[0025] The crystallinity of the nanocellulose material is at least 70% or at least 80%, in various embodiments.

[0026] The nanocellulose material may include nanofibrillated cellulose, nanocrystalline cellulose, or both nanofibrillated and nanocrystalline cellulose. The nanocellulose material may be characterized by an average degree of polymerization from about 100 to about 1500, such as from about 300 to about 700, or from about 150 to about 250.

[0027] Optionally, the process for producing a hydrophobic nanocellulose material may further include chemically modifying the lignin to increase hydrophobicity of the nanocellulose material. The chemical modification of lignin may be conducted during step (b), step (c), step (d), following step (d), or some combination.

[0028] The present invention also provides, in some variations, a process for producing a nanocellulose-containing product comprising nanocellulose particles having at least one length dimension of from 0.01nm to 1000nm, the process comprising:
  1. (a) providing a lignocellulosic biomass feedstock;
  2. (b) fractionating the feedstock in the presence of an acid, a solvent for lignin, and water, to generate cellulose-rich solids and a liquid containing hemicellulose and lignin;
  3. (c) mechanically treating the cellulose-rich solids with a total mechanical energy of less than about 1000 kilowatt-hours per ton (1.102 kWh/kg) of said cellulose-rich solids to form cellulose fibrils and/or cellulose crystals, thereby generating a nanocellulose material having a crystallinity of at least 60%; and
  4. (d) incorporating at least a portion of the nanocellulose material into a nanocellulose-containing product.


[0029] The nanocellulose-containing product includes the nanocellulose material, or a treated form thereof. In some embodiments, the nanocellulose-containing product consists essentially of the nanocellulose material.

[0030] In some embodiments, step (d) comprises forming a structural object that includes the nanocellulose material, or a derivative thereof.

[0031] In some embodiments, step (d) comprises forming a foam or aerogel that includes the nanocellulose material, or a derivative thereof.

[0032] In some embodiments, step (d) comprises combining the nanocellulose material, or a derivative thereof, with one or more other materials to form a composite. For example, the other material may include a polymer selected from polyolefins, polyesters, polyurethanes, polyamides, or combinations thereof. Alternatively, or additionally, the other material may include carbon in various forms.

[0033] The nanocellulose material incorporated into a nanocellulose-containing product may be at least partially hydrophobic via deposition of at least some of the lignin onto a surface of the cellulose-rich solids during step (b). Also, the nanocellulose material may be at least partially hydrophobic via deposition of at least some of the lignin onto a surface of the nanocellulose material during step (c) or step (d).

[0034] In some embodiments, step (d) comprises forming a film comprising the nanocellulose material, or a derivative thereof. The film is optically transparent and flexible, in certain embodiments.

[0035] In some embodiments, step (d) comprises forming a coating or coating precursor comprising the nanocellulose material, or a derivative thereof. In some embodiments, the nanocellulose-containing product is a paper coating.

[0036] In some embodiments, the nanocellulose-containing product is configured as a catalyst, catalyst substrate, or co-catalyst. In some embodiments, the nanocellulose-containing product is configured electrochemically for carrying or storing an electrical current or voltage.

[0037] In some embodiments, the nanocellulose-containing product is incorporated into a filter, membrane, or other separation device.

[0038] In some embodiments, the nanocellulose-containing product is incorporated as an additive into a coating, paint, or adhesive. In some embodiments, the nanocellulose-containing product is incorporated as a cement additive.

[0039] In some embodiments, the nanocellulose-containing product is incorporated as a thickening agent or rheological modifier. For example, the nanocellulose-containing product may be an additive in a drilling fluid, such as (but not limited to) an oil recovery fluid and/or a gas recovery fluid.

[0040] Nanocellulose compositions disclosed herein may comprise nanofibrillated cellulose with a cellulose crystallinity of about 70% or greater. The nanocellulose composition may include lignin and sulfur.

[0041] A nanocellulose composition may comprise nanofibrillated cellulose and nanocrystalline cellulose, wherein the nanocellulose composition is characterized by an overall cellulose crystallinity of about 70% or greater. The nanocellulose composition may include lignin and sulfur.

[0042] A nanocellulose composition may comprise nanocrystalline cellulose with a cellulose crystallinity of about 80% or greater, wherein the nanocellulose composition comprises lignin and sulfur.

[0043] The cellulose crystallinity may be about 75% or greater, such as about 80% or greater, or about 85% or greater. Preferably, the nanocellulose compositions disclosed herein are not derived from tunicates.

[0044] The nanocellulose composition disclosed herein is characterized by an average cellulose degree of polymerization from about 100 to about 1000, such as from about 300 to about 700 or from about 150 to about 250. The nanocellulose composition disclosed herein may be characterized by a cellulose degree of polymerization distribution having a single peak. The nanocellulose composition disclosed herein may be free of enzymes.

[0045] A hydrophobic nanocellulose composition disclosed herein may have a cellulose crystallinity of about 70% or greater, wherein the nanocellulose composition contains nanocellulose particles having a surface concentration of lignin that is greater than a bulk (internal particle) concentration of lignin. A coating or thin film of lignin may be on the nanocellulose particles, but the coating or film need not be uniform.

[0046] The hydrophobic nanocellulose composition disclosed herein may have a cellulose crystallinity is about 75% or greater, about 80% or greater, or about 85% or greater. The hydrophobic nanocellulose composition disclosed herein may further include sulfur.

[0047] The hydrophobic nanocellulose composition disclosed herein may or may not be derived from tunicates. The hydrophobic nanocellulose composition disclosed herein may be free of enzymes.

[0048] The hydrophobic nanocellulose composition disclosed herein may be characterized by an average cellulose degree of polymerization from about 100 to about 1500, such as from about 300 to about 700 or from about 150 to about 250. The nanocellulose composition disclosed herein may be characterized by a cellulose degree of polymerization distribution having a single peak.

[0049] A nanocellulose-containing product may include any of the disclosed nanocellulose compositions. Many nanocellulose-containing products are possible. For example, a nanocellulose-containing product may be selected from the group consisting of a structural object, a foam, an aerogel, a polymer composite, a carbon composite, a film, a coating, a coating precursor, a current or voltage carrier, a filter, a membrane, a catalyst, a catalyst substrate, a coating additive, a paint additive, an adhesive additive, a cement additive, a paper coating, a thickening agent, a rheological modifier, an additive for a drilling fluid, and combinations or derivatives thereof.

[0050] A nanocellulose material disclosed herein may be produced by a process comprising:
  1. (a) providing a lignocellulosic biomass feedstock;
  2. (b) fractionating the feedstock in the presence of an acid, a solvent for lignin, and water, to generate cellulose-rich solids and a liquid containing hemicellulose and lignin;
  3. (c) mechanically treating the cellulose-rich solids to form cellulose fibrils and/or cellulose crystals, thereby generating a nanocellulose material having a crystallinity of at least 60%; and
  4. (d) recovering the nanocellulose material.


[0051] A polymer-nanocellulose composite material disclosed herein may be produced by a process comprising:
  1. (a) providing a lignocellulosic biomass feedstock;
  2. (b) fractionating the feedstock in the presence of an acid, a solvent for lignin, and water, to generate cellulose-rich solids and a liquid containing hemicellulose and lignin;
  3. (c) mechanically treating the cellulose-rich solids to form cellulose fibrils and/or cellulose crystals, thereby generating a nanocellulose material having a crystallinity of at least 60%;
  4. (d) recovering the nanocellulose material;
  5. (e) fermenting hemicellulosic sugars derived from the hemicellulose to produce a monomer or precursor thereof;
  6. (f) polymerizing the monomer to produce a polymer; and
  7. (g) combining the polymer and the nanocellulose material to form the polymer-nanocellulose composite.


[0052] A nanocellulose material disclosed herein may also be produced by a process comprising:
  1. (a) providing a lignocellulosic biomass feedstock;
  2. (b) fractionating the feedstock in the presence of sulfur dioxide, a solvent for lignin, and water, to generate cellulose-rich solids and a liquid containing hemicellulose oligomers and lignin, wherein the crystallinity of the cellulose-rich solids is at least 70%, wherein SO2 concentration is from about 10 wt% to about 50 wt%, fractionation temperature is from about 130°C to about 200°C, and fractionation time is from about 30 minutes to about 4 hours;
  3. (c) mechanically treating the cellulose-rich solids to form cellulose fibrils and/or cellulose crystals, thereby generating a nanocellulose material having a crystallinity of at least 70%; and
  4. (d) recovering the nanocellulose material.


[0053] A further hydrophobic nanocellulose material disclosed herein may be produced by a process comprising:
  1. (a) providing a lignocellulosic biomass feedstock;
  2. (b) fractionating the feedstock in the presence of an acid, a solvent for lignin, and water, to generate cellulose-rich solids and a liquid containing hemicellulose and lignin, wherein a portion of the lignin deposits onto a surface of the cellulose-rich solids, thereby rendering the cellulose-rich solids at least partially hydrophobic;
  3. (c) mechanically treating the cellulose-rich solids to form cellulose fibrils and/or cellulose crystals, thereby generating a hydrophobic nanocellulose material having a crystallinity of at least 60%; and
  4. (d) recovering the hydrophobic nanocellulose material.


[0054] Another nanocellulose-containing product disclosed herein may be produced by a process comprising:
  1. (a) providing a lignocellulosic biomass feedstock;
  2. (b) fractionating the feedstock in the presence of an acid, a solvent for lignin, and water, to generate cellulose-rich solids and a liquid containing hemicellulose and lignin;
  3. (c) mechanically treating the cellulose-rich solids to form cellulose fibrils and/or cellulose crystals, thereby generating a nanocellulose material having a crystallinity of at least 60%; and
  4. (d) incorporating at least a portion of the nanocellulose material into a nanocellulose-containing product.


[0055] A product that includes the nanocellulose material disclosed herein may be selected from the group consisting of a structural object, a foam, an aerogel, a polymer composite, a carbon composite, a film, a coating, a coating precursor, a current or voltage carrier, a filter, a membrane, a catalyst, a catalyst substrate, a coating additive, a paint additive, an adhesive additive, a cement additive, a paper coating, a thickening agent, a rheological modifier, an additive for a drilling fluid, and combinations or derivatives thereof.

BRIEF DESCRIPTION OF THE FIGURES



[0056] 

FIG. 1 depicts the production of nanocellulose materials from biomass.

FIG. 2 depicts the production of nanocellulose materials from biomass.

FIG. 3 depicts the production of nanocellulose materials from biomass.

FIG. 4 depicts the production of nanocellulose materials from biomass.

FIG. 5 is a graph showing experimental degree of polymerization of nanocellulose versus fractionation time.

FIG. 6 is a graph showing experimental Kappa number of nanocellulose versus fractionation time.

FIG. 7 is a scanning-electron microscopy image of cellulose nano fibrils.

FIG. 8 is a scanning electron microscopy image of cellulose nano crystals.

FIG. 9 is a transmission electron microscopy image of cellulose nanocrystals (whiskers).


DETAILED DESCRIPTION OF SOME EMBODIMENTS



[0057] 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 apparent to those skilled in the art when taken with reference to the following detailed description of the invention in conjunction with any accompanying drawings.

[0058] As used in this specification and the appended claims, the singular forms "a," "an," and "the" include plural referents unless the context clearly indicates otherwise. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as is commonly understood by one of ordinary skill in the art to which this invention belongs. All composition numbers and ranges based on percentages are weight percentages, unless indicated otherwise. All ranges of numbers or conditions are meant to encompass any specific value contained within the range, rounded to any suitable decimal point.

[0059] Unless otherwise indicated, all numbers expressing parameters, reaction conditions, concentrations of components, 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 a specific analytical technique.

[0060] The term "comprising," which 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 which means that the named claim elements are essential, but other claim elements may be added and still form a construct within the scope of the claim.

[0061] As used herein, the phase "consisting of' excludes any element, step, or ingredient not specified in the claim. When the phrase "consists of' (or variations thereof) appears in a clause of the body of a claim, rather than immediately following the preamble, it limits only the element set forth in that clause; other elements are not excluded from the claim as a whole. As used herein, the phase "consisting essentially of' limits the scope of a claim to the specified elements or method steps, plus those that do not materially affect the basis and novel characteristic(s) of the claimed subject matter.

[0062] 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 may include the use of either of the other two terms. Thus in some embodiments not otherwise explicitly recited, any instance of "comprising" may be replaced by "consisting of' or, alternatively, by "consisting essentially of."

[0063] Generally it is beneficial to process biomass in a way that effectively separates the major fractions (cellulose, hemicellulose, and lignin) from each other. The cellulose can be subjected to further processing to produce nanocellulose. Fractionation of lignocellulosics leads to release of cellulosic fibers and opens the cell wall structure by dissolution of lignin and hemicellulose between the cellulose microfibrils. The fibers become more accessible for conversion to nanofibrils or nanocrystals. Hemicellulose sugars can be fermented to a variety of products, such as ethanol, or converted to other chemicals. Lignin from biomass has value as a solid fuel and also as an energy feedstock to produce liquid fuels, synthesis gas, or hydrogen; and as an intermediate to make a variety of polymeric compounds. Additionally, minor components such as proteins or rare sugars can be extracted and purified for specialty applications.

[0064] This disclosure describes processes and apparatus to efficiently fractionate any lignocellulosic-based biomass into its primary major components (cellulose, lignin, and if present, hemicellulose) so that each can be used in potentially distinct processes. An advantage of the process is that it produces cellulose-rich solids while concurrently producing a liquid phase containing a high yield of both hemicellulose sugars and lignin, and low quantities of lignin and hemicellulose degradation products. The flexible fractionation technique enables multiple uses for the products. The cellulose is an advantaged precursor for producing nanocellulose, as will be described herein.

[0065] The present invention, in some variations, is premised on the discovery that nanocellulose and related materials can be produced under certain conditions including process conditions and steps associated with the AVAP® process. It has been found, surprisingly, that very high crystallinity can be produced and maintained during formation of nano fibers or nanocrystals, without the need for an enzymatic or separate acid treatment step to hydrolyze amorphous cellulose. High crystallinity can translate to mechanically strong fibers or good physical reinforcing properties, which are advantageous for composites, reinforced polymers, and high-strength spun fibers and textiles, for example.

[0066] A significant techno-economic barrier for production of cellulose nanofibrils (CNF) is high energy consumption and high cost. Using sulfur dioxide (SO2) and ethanol (or other solvent), the pretreatment disclosed herein effectively removes not only hemicelluloses and lignin from biomass but also the amorphous regions of cellulose, giving a unique, highly crystalline cellulose product that requires minimal mechanical energy for conversion to CNF. The low mechanical energy requirement results from the fibrillated cellulose network formed during chemical pretreatment upon removal of the amorphous regions of cellulose.

[0067] As intended herein, "nanocellulose" is broadly defined to include a range of cellulosic materials, including but not limited to microfibrillated cellulose, nanofibrillated cellulose, microcrystalline cellulose, nanocrystalline cellulose, and particulated or fibrillated dissolving pulp. Nanocellulose as provided herein includes particles having at least one length dimension (e.g., diameter) on the nanometer scale, from 0.01nm to 1000nm.

[0068] "Nanofibrillated cellulose" or equivalently "cellulose nanofibrils" means cellulose fibers or regions that contain nanometer-sized particles or fibers, or both micron-sized and nanometer-sized particles or fibers. "Nanocrystalline cellulose" or equivalently "cellulose nanocrystals" means cellulose particles, regions, or crystals that contain nanometer-sized domains, or both micron-sized and nanometer-sized domains. "Micron-sized" includes from 1 µm to 100 µm and "nanometer-sized" includes from 0.01 nm to 1000 nm (1 µm). Larger domains (including long fibers) may also be present in these materials.

[0069] 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 steps may be varied, some steps may be omitted, and/or other steps may be added. Reference herein to first step, second step, etc. is for purposes of illustrating some embodiments only.

[0070] In some variations, the present invention provides a process for producing a nanocellulose material comprising nanocellulose particles having at least one length dimension of from 0.01nm to 1000nm, the process comprising:
  1. (a) providing a lignocellulosic biomass feedstock;
  2. (b) fractionating the feedstock in the presence of an acid, a solvent for lignin, and water, to generate cellulose-rich solids and a liquid containing hemicellulose and lignin;
  3. (c) mechanically treating the cellulose-rich solids with a total mechanical energy of less than about 1000 kilowatt-hours per ton (1.102 kWh/kg) of said cellulose-rich solids to form cellulose fibrils and/or cellulose crystals, thereby generating a nanocellulose material having a crystallinity (i.e., cellulose crystallinity) of at least 60%; and
  4. (d) recovering the nanocellulose material.


[0071] In some embodiments, the acid is selected from the group consisting of sulfur dioxide, sulfurous acid, sulfur trioxide, sulfuric acid, lignosulfonic acid, and combinations thereof. In particular embodiments, the acid is sulfur dioxide.

[0072] The biomass feedstock may be selected from hardwoods, softwoods, forest residues, eucalyptus, industrial wastes, pulp and paper wastes, consumer wastes, or combinations thereof. Some embodiments utilize agricultural residues, which include lignocellulosic biomass associated with food crops, annual grasses, energy crops, or other annually renewable feedstocks. Exemplary agricultural residues include, but are not limited to, corn stover, corn fiber, wheat straw, sugarcane bagasse, sugarcane straw, rice straw, oat straw, barley straw, miscanthus, energy cane straw/residue, or combinations thereof. The process disclosed herein benefits from feedstock flexibility; it is effective for a wide variety of cellulose-containing feedstocks.

[0073] As used herein, "lignocellulosic biomass" means any material containing cellulose and lignin. Lignocellulosic biomass may also contain hemicellulose. Mixtures of one or more types of biomass can be used. In some embodiments, the biomass feedstock comprises both a lignocellulosic component (such as one described above) in addition to a sucrose-containing component (e.g., sugarcane 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. In general, the biomass is in the form of a particulate or chip, but particle size is not critical in this invention.

[0074] During step (c), the cellulose-rich solids are treated with a total mechanical energy of less than about 1000 kilowatt-hours per ton (1.102 kWh/kg) of the cellulose-rich solids, such as less than about 950, 900, 850, 800, 750, 700, 650, 600, 550, 500, 450, 400, 350, 300, or 250 kilowatt-hours per ton (less than about 1.05, 0.992, 0.937, 0.881, 0.827, 0.772, 0.717, 0.661, 0.606, 0.551, 0.496, 0.441, 0.386, 0.331, or 0.276 kWh/kg) of the cellulose-rich solids. In certain embodiments, the total mechanical energy is from about 100 kilowatt-hours per ton (0.110 kWh/kg) to about 400 kilowatt-hours per ton (0.441 kWh/kg) of the cellulose-rich solids. Energy consumption may be measured in any other suitable units. An ammeter measuring current drawn by a motor driving the mechanical treatment device is one way to obtain an estimate of the total mechanical energy.

[0075] Mechanically treating in step (c) may employ one or more known techniques such as, but by no means limited to, milling, grinding, beating, sonicating, or any other means to form or release nanofibrils and/or nanocrystals in the cellulose. Essentially, any type of mill or device that physically separates fibers may be utilized. Such mills are well-known in the industry and include, without limitation, Valley beaters, single disk refiners, double disk refiners, conical refiners, including both wide angle and narrow angle, cylindrical refiners, homogenizers, micro fluidizers, and other similar milling or grinding apparatus. See, for example, Smook, Handbook for Pulp & Paper Technologists, Tappi Press, 1992; and Hubbe et al., "Cellulose Nanocomposites: A Review," BioResources 3(3), 929-980 (2008).

[0076] The extent of mechanical treatment may be monitored during the process by any of several means. Certain optical instruments can provide continuous data relating to the fiber length distributions and % fines, either of which may be used to define endpoints for the mechanical treatment step. The time, temperature, and pressure may vary during mechanical treatment. For example, in some embodiments, sonication for a time from about 5 minutes to 2 hours, at ambient temperature and pressure, may be utilized.

[0077] In some embodiments, a portion of the cellulose-rich solids is converted to nano fibrils while the remainder of the cellulose-rich solids is not fibrillated. In various embodiments, about 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 95%, 99%, or substantially all of the cellulose-rich solids are fibrillated into nanofibrils.

[0078] In some embodiments, a portion of the nanofibrils is converted to nanocrystals while the remainder of the nanofibrils is not converted to nanocrystals. In various embodiments, about 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 95%, 99%, or substantially all of the nanofibrils are converted to nanocrystals. During drying, it is possible for a small amount of nanocrystals to come back together and form nanofibrils.

[0079] Following mechanical treatment, the nanocellulose material may be classified by particle size. A portion of material may be subjected to a separate process, such as enzymatic hydrolysis to produce glucose. Such material may have good crystallinity, for example, but may not have desirable particle size or degree of polymerization.

[0080] Step (c) may further comprise treatment of the cellulose-rich solids with one or more enzymes or with one or more acids. When acids are employed, they may be selected from the group consisting of sulfur dioxide, sulfurous acid, lignosulfonic acid, acetic acid, formic acid, and combinations thereof. Acids associated with hemicellulose, such as acetic acid or uronic acids, may be employed, alone or in conjunction with other acids. Also, step (c) may include treatment of the cellulose-rich solids with heat. In some embodiments, step (c) does not employ any enzymes or acids.

[0081] In step (c), when an acid is employed, the acid may be a strong acid such as sulfuric acid, nitric acid, or phosphoric acid, for example. Weaker acids may be employed, under more severe temperature and/or time. Enzymes that hydrolyze cellulose (i.e., cellulases) and possibly hemicellulose (i.e., with hemicellulase activity) may be employed in step (c), either instead of acids, or potentially in a sequential configuration before or after acidic hydrolysis.

[0082] In some embodiments, the process comprises enzymatically treating the cellulose-rich solids to hydrolyze amorphous cellulose. In other embodiments, or sequentially prior to or after enzymatic treatment, the process may comprise acid-treating the cellulose-rich solids to hydrolyze amorphous cellulose.

[0083] In some embodiments, the process further comprises enzymatically treating the nanocrystalline cellulose. In other embodiments, or sequentially prior to or after enzymatic treatment, the process further comprises acid-treating treating the nanocrystalline cellulose.

[0084] If desired, an enzymatic treatment may be employed prior to, or possibly simultaneously with, the mechanical treatment. However, in preferred embodiments, no enzyme treatment is necessary to hydrolyze amorphous cellulose or weaken the structure of the fiber walls before isolation of nanofibers.

[0085] Following mechanical treatment, the nanocellulose may be recovered. Separation of cellulose nanofibrils and/or nanocrystals may be accomplished using apparatus capable of disintegrating the ultrastructure of the cell wall while preserving the integrity of the nanofibrils. For example, a homogenizer may be employed. In some embodiments, cellulose aggregate fibrils are recovered, having component fibrils in range of 1-100 nm width, wherein the fibrils have not been completely separated from each other.

[0086] The process may further comprise bleaching the cellulose-rich solids prior to step (c) and/or as part of step (c). Alternatively, or additionally, the process may further comprise bleaching the nanocellulose material during step (c) and/or following step (c). Any known bleaching technology or sequence may be employed, including enzymatic bleaching.

[0087] The nanocellulose material may include, or consist essentially of, nanofibrillated cellulose. The nanocellulose material may include, or consist essentially of, nanocrystalline cellulose. In some embodiments, the nanocellulose material may include, or consist essentially of, nanofibrillated cellulose and nanocrystalline cellulose.

[0088] In some embodiments, the crystallinity of the cellulose-rich solids (i.e., the nanocellulose precursor material) is at least 60%, 61%, 62%, 63%, 64%, 65%, 66%, 67%, 68%, 69%, 70%, 71%, 72%, 73%, 74%, 75%, 76%, 77%, 78%, 79%, 80%, 81%, 82%, 83%, 84%, 85%, 86% or higher. In these or other embodiments, the crystallinity of the nanocellulose material is at least 60%, 61%, 62%, 63%, 64%, 65%, 66%, 67%, 68%, 69%, 70%, 71%, 72%, 73%, 74%, 75%, 76%, 77%, 78%, 79%, 80%, 81%, 82%, 83%, 84%, 85%, 86% or higher. The crystallinity may be measured using any known techniques. For example, X-ray diffraction and solid-state 13C nuclear magnetic resonance may be utilized.

[0089] It is remarkable that the nanocellulose precursor material has high crystallinity-which generally contributes to mechanical strength-yet, very low mechanical energy consumption is necessary to break apart the nanocellulose precursor material into nanofibrils and nanocrystals. It is believed that since the mechanical energy input is low, the high crystallinity is essentially maintained in the final product.

[0090] In some embodiments, the nanocellulose material is characterized by an average degree of polymerization from about 100 to about 1500, such as about 125, 150, 175, 200, 225, 250, 300, 400, 500, 600, 700, 800, 900, 1000, 1100, 1200, 1300, or 1400. For example, the nanocellulose material may be characterized by an average degree of polymerization from about 300 to about 700, or from about 150 to about 250. The nanocellulose material, when in the form of nanocrystals, may have a degree of polymerization less than 100, such as about 75, 50, 25, or 10. Portions of the material may have a degree of polymerization that is higher than 1500, such as about 2000, 3000, 4000, or 5000.

[0091] In some embodiments, the nanocellulose material is characterized by a degree of polymerization distribution having a single peak. In other embodiments, the nanocellulose material is characterized by a degree of polymerization distribution having two peaks, such as one centered in the range of 150-250 and another peak centered in the range of 300-700.

[0092] In some embodiments, the nanocellulose material is characterized by an average length-to-width aspect ratio of particles from about 10 to about 1000, such as about 15, 20, 25, 35, 50, 75, 100, 150, 200, 250, 300, 400, or 500. Nanofibrils are generally associated with higher aspect ratios than nanocrystals. Nanocrystals, for example, may have a length range of about 100 nm to 500 nm and a diameter of about 4 nm, translating to an aspect ratio of 25 to 125. Nanofibrils may have a length of about 2000 nm and diameter range of 5 to 50 nm, translating 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.

[0093] Optionally, the process further comprises hydrolyzing amorphous cellulose into glucose in step (b) and/or step (c), recovering the glucose, and fermenting the glucose to a fermentation product. Optionally, the process further comprises recovering, fermenting, or further treating hemicellulosic sugars derived from the hemicellulose. Optionally, the process further comprises recovering, combusting, or further treating the lignin.

[0094] Glucose that is generated from hydrolysis of amorphous cellulose may be integrated into an overall process to produce ethanol, or another fermentation co-product. Thus in some embodiments, the process further comprises hydrolyzing amorphous cellulose into glucose in step (b) and/or step (c), and recovering the glucose. The glucose may be purified and sold. Or the glucose may be fermented to a fermentation product, such as but not limited to ethanol. The glucose or a fermentation product may be recycled to the front end, such as to hemicellulose sugar processing, if desired.

[0095] When hemicellulosic sugars are recovered and fermented, they may be fermented to produce a monomer or precursor thereof. The monomer may be polymerized to produce a polymer, which may then be combined with the nanocellulose material to form a polymer-nanocellulose composite.

[0096] In some embodiments, the nanocellulose material is at least partially hydrophobic via deposition of at least some of the lignin onto a surface of the cellulose-rich solids during step (b). In these or other embodiments, the nanocellulose material is at least partially hydrophobic via deposition of at least some of the lignin onto a surface of the nanocellulose material during step (c) or step (d).

[0097] In some embodiments, the process further comprises chemically converting the nanocellulose material to one or more nanocellulose derivatives. For example, nanocellulose derivatives may be selected from the group consisting of nanocellulose esters, nanocellulose ethers, nanocellulose ether esters, alkylated nanocellulose compounds, cross-linked nanocellulose compounds, acid-functionalized nanocellulose compounds, base-functionalized nanocellulose compounds, and combinations thereof.

[0098] Various types of nanocellulose functionalization or derivatization may be employed, such as functionalization using polymers, chemical surface modification, functionalization using nanoparticles (i.e. other nanoparticles besides the nanocellulose), modification with inorganics or surfactants, or biochemical modification.

[0099] Certain variations provide a process for producing a nanocellulose material comprising nanocellulose particles having at least one length dimension of from 0.01nm to 1000nm, the process comprising:
  1. (a) providing a lignocellulosic biomass feedstock;
  2. (b) fractionating the feedstock in the presence of sulfur dioxide, a solvent for lignin, and water, to generate cellulose-rich solids and a liquid containing hemicellulose oligomers and lignin, wherein the crystallinity of the cellulose-rich solids is at least 70%, wherein SO2 concentration is from about 10 wt% to about 50 wt%, fractionation temperature is from about 130°C to about 200°C, and fractionation time is from about 30 minutes to about 4 hours;
  3. (c) mechanically treating the cellulose-rich solids with a total mechanical energy of less than about 1000 kilowatt-hours per ton (1.102 kWh/kg) to form cellulose fibrils and/or cellulose crystals, thereby generating a nanocellulose material having a crystallinity of at least 70%; and
  4. (d) recovering the nanocellulose material.


[0100] In some embodiments, the SO2 concentration is from about 12 wt% to about 30 wt%. In some embodiments, the fractionation temperature is from about 140°C to about 170°C. In some embodiments, the fractionation time is from about 1 hour to about 2 hours. The process may be controlled such that during step (b), a portion of the solubilized lignin intentionally deposits back onto a surface of the cellulose-rich solids, thereby rendering the cellulose-rich solids at least partially hydrophobic.

[0101] A significant factor limiting the application of strength-enhancing, lightweight nanocellulose in composites is cellulose's inherent hydrophilicity. Surface modification of the nanocellulose surface to impart hydrophobicity to enable uniform dispersion in a hydrophobic polymer matrix is an active area of study. It has been discovered that when preparing nanocellulose using the processes described herein, lignin may condense on pulp under certain conditions, giving a rise in Kappa number and production of a brown or black material. The lignin increases the hydrophobicity of the nanocellulose precursor material, and that hydrophobicity is retained during mechanical treatment provided that there is not removal of the lignin through bleaching or other steps. (Some bleaching may still be performed, either to adjust lignin content or to attack a certain type of lignin, for example.)

[0102] In some embodiments, the present invention provides a process for producing a hydrophobic nanocellulose material comprising nanocellulose particles having at least one length dimension of from 0.01nm to 1000nm, the process comprising:
  1. (a) providing a lignocellulosic biomass feedstock;
  2. (b) fractionating the feedstock in the presence of an acid, a solvent for lignin, and water, to generate cellulose-rich solids and a liquid containing hemicellulose and lignin, wherein a portion of the lignin deposits onto a surface of the cellulose-rich solids, thereby rendering the cellulose-rich solids at least partially hydrophobic;
  3. (c) mechanically treating the cellulose-rich solids with a total mechanical energy of less than about 1000 kilowatt-hours per ton (1.102 kWh/kg) to form cellulose fibrils and/or cellulose crystals, thereby generating a hydrophobic nanocellulose material having a crystallinity of at least 60%; and
  4. (d) recovering the hydrophobic nanocellulose material.


[0103] In some embodiments, the acid is selected from the group consisting of sulfur dioxide, sulfurous acid, sulfur trioxide, sulfuric acid, lignosulfonic acid, and combinations thereof.

[0104] In some embodiments, during step (c), the cellulose-rich solids are treated with a total mechanical energy of less than about 1000 kilowatt-hours per ton (1.102 kWh/kg) of the cellulose-rich solids, such as less than about 500 kilowatt-hours per ton (0.551 kWh/kg) of the cellulose-rich solids.

[0105] The crystallinity of the nanocellulose material is at least 70% or at least 80%, in various embodiments.

[0106] The nanocellulose material may include nanofibrillated cellulose, nanocrystalline cellulose, or both nanofibrillated and nanocrystalline cellulose. The nanocellulose material may be characterized by an average degree of polymerization from about 100 to about 1500, such as from about 300 to about 700, or from about 150 to about 250, for example (without limitation).

[0107] Step (b) may include process conditions, such as extended time and/or temperature (e.g., see FIG. 6), or reduced concentration of solvent for lignin, which tend to promote lignin deposition onto fibers. Alternatively, or additionally, step (b) may include one or more washing steps that are adapted to deposit at least some of the lignin that was solubilized during the initial fractionation. One approach is to wash with water rather than a solution of water and solvent. Because lignin is generally not soluble in water, it will begin to precipitate. Optionally, other conditions may be varied, such as pH and temperature, during fractionation, washing, or other steps, to optimize the amount of lignin deposited on surfaces. It is noted that in order for the lignin surface concentration to be higher than the bulk concentration, the lignin needs to be first pulled into solution and then redeposited; internal lignin (within particles of nanocellulose) does not enhance hydrophobicity in the same way.

[0108] Optionally, the process for producing a hydrophobic nanocellulose material may further include chemically modifying the lignin to increase hydrophobicity of the nanocellulose material. The chemical modification of lignin may be conducted during step (b), step (c), step (d), following step (d), or some combination.

[0109] High loading rates of lignin have been achieved in thermoplastics. Even higher loading levels are obtained with well-known modifications of lignin. The preparation of useful polymeric materials containing a substantial amount of lignin has been the subject of investigations for more than thirty years. Typically, lignin may be blended into polyolefins or polyesters by extrusion up to 25-40 wt% while satisfying mechanical characteristics. In order to increase the compatibility between lignin and other hydrophobic polymers, different approaches have been used. For example, chemical modification of lignin may be accomplished through esterification with long-chain fatty acids.

[0110] Any known chemical modifications may be carried out on the lignin, to further increase the hydrophobic nature of the lignin-coated nanocellulose material provided by embodiments of this invention.

[0111] The present invention also provides, in some variations, a process for producing a nanocellulose-containing product comprising nanocellulose particles having at least one length dimension of from 0.01nm to 1000nm, the process comprising:
  1. (a) providing a lignocellulosic biomass feedstock;
  2. (b) fractionating the feedstock in the presence of an acid, a solvent for lignin, and water, to generate cellulose-rich solids and a liquid containing hemicellulose and lignin;
  3. (c) mechanically treating the cellulose-rich solids with a total mechanical energy of less than about 1000 kilowatt-hours per ton (1.102 kWh/kg) to form cellulose fibrils and/or cellulose crystals, thereby generating a nanocellulose material having a crystallinity of at least 60%; and
  4. (d) incorporating at least a portion of the nanocellulose material into a nanocellulose-containing product.


[0112] The nanocellulose-containing product includes the nanocellulose material, or a treated form thereof. In some embodiments, the nanocellulose-containing product consists essentially of the nanocellulose material.

[0113] In some embodiments, step (d) comprises forming a structural object that includes the nanocellulose material, or a derivative thereof.

[0114] In some embodiments, step (d) comprises forming a foam or aerogel that includes the nanocellulose material, or a derivative thereof.

[0115] In some embodiments, step (d) comprises combining the nanocellulose material, or a derivative thereof, with one or more other materials to form a composite. For example, the other material may include a polymer selected from polyolefins, polyesters, polyurethanes, polyamides, or combinations thereof. Alternatively, or additionally, the other material may include carbon in various forms.

[0116] The nanocellulose material incorporated into a nanocellulose-containing product may be at least partially hydrophobic via deposition of at least some of the lignin onto a surface of the cellulose-rich solids during step (b). Also, the nanocellulose material may be at least partially hydrophobic via deposition of at least some of the lignin onto a surface of the nanocellulose material during step (c) or step (d).

[0117] In some embodiments, step (d) comprises forming a film comprising the nanocellulose material, or a derivative thereof. The film is optically transparent and flexible, in certain embodiments.

[0118] In some embodiments, step (d) comprises forming a coating or coating precursor comprising the nanocellulose material, or a derivative thereof. In some embodiments, the nanocellulose-containing product is a paper coating.

[0119] In some embodiments, the nanocellulose-containing product is configured as a catalyst, catalyst substrate, or co-catalyst. In some embodiments, the nanocellulose-containing product is configured electrochemically for carrying or storing an electrical current or voltage.

[0120] In some embodiments, the nanocellulose-containing product is incorporated into a filter, membrane, or other separation device.

[0121] In some embodiments, the nanocellulose-containing product is incorporated as an additive into a coating, paint, or adhesive. In some embodiments, the nanocellulose-containing product is incorporated as a cement additive.

[0122] In some embodiments, the nanocellulose-containing product is incorporated as a thickening agent or rheological modifier. For example, the nanocellulose-containing product may be an additive in a drilling fluid, such as (but not limited to) an oil recovery fluid and/or a gas recovery fluid.

[0123] Nanocellulose compositions are disclosed herein, such as a nanocellulose composition comprising nanofibrillated cellulose with a cellulose crystallinity of about 70% or greater. The nanocellulose composition may include lignin and sulfur.

[0124] The nanocellulose material may further contain some sulfonated lignin that is derived from sulfonation reactions with SO2 (when used as the acid in fractionation) during the biomass digestion. The amount of sulfonated lignin may be about 0.1 wt% (or less), 0.2 wt%, 0.5 wt%, 0.8 wt%, 1 wt%, or more. Also, without being limited by any theory, it is speculated that a small amount of sulfur may chemically react with cellulose itself, in some embodiments.

[0125] A nanocellulose composition disclosed herein may comprise nanofibrillated cellulose and nanocrystalline cellulose, wherein the nanocellulose composition is characterized by an overall cellulose crystallinity of about 70% or greater. The nanocellulose composition may include lignin and sulfur.

[0126] A nanocellulose composition disclosed herein may comprise nanocrystalline cellulose with a cellulose crystallinity of about 80% or greater, wherein the nanocellulose composition comprises lignin and sulfur.

[0127] The cellulose crystallinity may be about 75% or greater, such as about 80% or greater, or about 85% or greater.

[0128] The nanocellulose composition disclosed herein may be characterized by an average cellulose degree of polymerization from about 100 to about 1000, such as from about 300 to about 700 or from about 150 to about 250. The nanocellulose composition disclosed herein may be characterized by a cellulose degree of polymerization distribution having a single peak. The nanocellulose composition disclosed herein may be free of enzymes.

[0129] Other variations include a hydrophobic nanocellulose composition with a cellulose crystallinity of about 70% or greater, wherein the nanocellulose composition contains nanocellulose particles having a surface concentration of lignin that is greater than a bulk (internal particle) concentration of lignin. There may be a coating or thin film of lignin on nanocellulose particles, but the coating or film need not be uniform.

[0130] The hydrophobic nanocellulose composition disclosed herein may have a cellulose crystallinity is about 75% or greater, about 80% or greater, or about 85% or greater. The hydrophobic nanocellulose composition disclosed herein may further include sulfur.

[0131] The hydrophobic nanocellulose composition disclosed herein may or may not be derived from tunicates. The hydrophobic nanocellulose disclosed herein composition may be free of enzymes.

[0132] The hydrophobic nanocellulose composition disclosed herein may be characterized by an average cellulose degree of polymerization from about 100 to about 1500, such as from about 300 to about 700 or from about 150 to about 250. The nanocellulose composition disclosed herein may be characterized by a cellulose degree of polymerization distribution having a single peak.

[0133] A nanocellulose-containing product may include any of the disclosed nanocellulose compositions disclosed herein. Many nanocellulose-containing products are possible. For example, a nanocellulose-containing product may be selected from the group consisting of a structural object, a foam, an aerogel, a polymer composite, a carbon composite, a film, a coating, a coating precursor, a current or voltage carrier, a filter, a membrane, a catalyst, a catalyst substrate, a coating additive, a paint additive, an adhesive additive, a cement additive, a paper coating, a thickening agent, a rheological modifier, an additive for a drilling fluid, and combinations or derivatives thereof.

[0134] A nanocellulose material disclosed herein may be produced by a process comprising:
  1. (a) providing a lignocellulosic biomass feedstock;
  2. (b) fractionating the feedstock in the presence of an acid, a solvent for lignin, and water, to generate cellulose-rich solids and a liquid containing hemicellulose and lignin;
  3. (c) mechanically treating the cellulose-rich solids to form cellulose fibrils and/or cellulose crystals, thereby generating a nanocellulose material having a crystallinity of at least 60%; and
  4. (d) recovering the nanocellulose material.


[0135] A polymer-nanocellulose composite material disclosed herein may be produced by a process comprising:
  1. (a) providing a lignocellulosic biomass feedstock;
  2. (b) fractionating the feedstock in the presence of an acid, a solvent for lignin, and water, to generate cellulose-rich solids and a liquid containing hemicellulose and lignin;
  3. (c) mechanically treating the cellulose-rich solids to form cellulose fibrils and/or cellulose crystals, thereby generating a nanocellulose material having a crystallinity of at least 60%;
  4. (d) recovering the nanocellulose material;
  5. (e) fermenting hemicellulosic sugars derived from the hemicellulose to produce a monomer or precursor thereof;
  6. (f) polymerizing the monomer to produce a polymer; and
  7. (g) combining the polymer and the nanocellulose material to form the polymer-nanocellulose composite.


[0136] A nanocellulose material disclosed herein may be produced by a process comprising:
  1. (a) providing a lignocellulosic biomass feedstock;
  2. (b) fractionating the feedstock in the presence of sulfur dioxide, a solvent for lignin, and water, to generate cellulose-rich solids and a liquid containing hemicellulose oligomers and lignin, wherein the crystallinity of the cellulose-rich solids is at least 70%, wherein SO2 concentration is from about 10 wt% to about 50 wt%, fractionation temperature is from about 130°C to about 200°C, and fractionation time is from about 30 minutes to about 4 hours;
  3. (c) mechanically treating the cellulose-rich solids to form cellulose fibrils and/or cellulose crystals, thereby generating a nanocellulose material having a crystallinity of at least 70%; and
  4. (d) recovering the nanocellulose material.


[0137] A hydrophobic nanocellulose material disclosed herein may be produced by a process comprising:
  1. (a) providing a lignocellulosic biomass feedstock;
  2. (b) fractionating the feedstock in the presence of an acid, a solvent for lignin, and water, to generate cellulose-rich solids and a liquid containing hemicellulose and lignin, wherein a portion of the lignin deposits onto a surface of the cellulose-rich solids, thereby rendering the cellulose-rich solids at least partially hydrophobic;
  3. (c) mechanically treating the cellulose-rich solids to form cellulose fibrils and/or cellulose crystals, thereby generating a hydrophobic nanocellulose material having a crystallinity of at least 60%; and
  4. (d) recovering the hydrophobic nanocellulose material.


[0138] A nanocellulose-containing product disclosed herein may be produced by a process comprising:
  1. (a) providing a lignocellulosic biomass feedstock;
  2. (b) fractionating the feedstock in the presence of an acid, a solvent for lignin, and water, to generate cellulose-rich solids and a liquid containing hemicellulose and lignin;
  3. (c) mechanically treating the cellulose-rich solids to form cellulose fibrils and/or cellulose crystals, thereby generating a nanocellulose material having a crystallinity of at least 60%; and
  4. (d) incorporating at least a portion of the nanocellulose material into a nanocellulose-containing product.


[0139] A nanocellulose-containing product that contains the nanocellulose material may be selected from the group consisting of a structural object, a foam, an aerogel, a polymer composite, a carbon composite, a film, a coating, a coating precursor, a current or voltage carrier, a filter, a membrane, a catalyst, a catalyst substrate, a coating additive, a paint additive, an adhesive additive, a cement additive, a paper coating, a thickening agent, a rheological modifier, an additive for a drilling fluid, and combinations or derivatives thereof.

[0140] Some process variations may be understood with reference to FIGS. 1-4. Dotted lines denote optional streams. Various embodiments will now be further described, without limitation as to the scope of the invention as defined in the appended claims. These embodiments are exemplary in nature.

[0141] In some embodiments, a first process step is "cooking" (equivalently, "digesting") which fractionates the three lignocellulosic material components (cellulose, hemicellulose, and lignin) to allow easy downstream removal. Specifically, hemicelluloses are dissolved and over 50% are completely hydrolyzed; cellulose is separated but remains resistant to hydrolysis; and part of the lignin is sulfonated into water-soluble lignosulfonates.

[0142] The lignocellulosic material is processed in a solution (cooking liquor) of aliphatic alcohol, water, and sulfur dioxide. The cooking liquor preferably contains at least 10 wt%, such as at least 20 wt%, 30 wt%, 40 wt%, or 50 wt% of a solvent for lignin. For example, the cooking liquor may contain about 30-70 wt% solvent, such as about 50 wt% solvent. The solvent for lignin may be an aliphatic alcohol, such as methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, isobutanol, 1-pentanol, 1-hexanol, or cyclohexanol. The solvent for lignin may be an aromatic alcohol, such as phenol or cresol. Other lignin solvents are possible, such as (but not limited to) glycerol, methyl ethyl ketone, or diethyl ether. Combinations of more than one solvent may be employed.

[0143] Preferably, enough solvent is included in the extractant mixture to dissolve the lignin present in the starting material. The solvent for lignin may be completely miscible, partially miscible, or immiscible with water, so that there may be more than one liquid phase. Potential process advantages arise when the solvent is miscible with water, and also when the solvent is immiscible with water. When the solvent is water-miscible, a single liquid phase forms, so mass transfer of lignin and hemicellulose extraction is enhanced, and the downstream process must only deal with one liquid stream. When the solvent is immiscible in water, the extractant mixture readily separates to form liquid phases, so a distinct separation step can be avoided or simplified. This can be advantageous if one liquid phase contains most of the lignin and the other contains most of the hemicellulose sugars, as this facilitates recovering the lignin from the hemicellulose sugars.

[0144] The cooking liquor preferably contains sulfur dioxide and/or sulfurous acid (H2SO3). The cooking liquor preferably contains SO2, in dissolved or reacted form, in a concentration of at least 3 wt%, preferably at least 6 wt%, more preferably at least 8 wt%, such as about 9 wt%, 10 wt%, 11 wt%, 12 wt%, 13 wt%, 14 wt%, 15 wt%, 20 wt%, 25 wt%, 30 wt% or higher. The cooking liquor may also contain one or more species, separately from SO2, to adjust the pH. The pH of the cooking liquor is typically about 4 or less.

[0145] Sulfur dioxide is a preferred acid catalyst, because it can be recovered easily from solution after hydrolysis. The majority of the SO2 from the hydrolysate may be stripped and recycled back to the reactor. Recovery and recycling translates to less lime required compared to neutralization of comparable sulfuric acid, less solids to dispose of, and less separation equipment. The increased efficiency owing to the inherent properties of sulfur dioxide mean that less total acid or other catalysts may be required. This has cost advantages, since sulfuric acid can be expensive. Additionally, and quite significantly, less acid usage also will translate into lower costs for a base (e.g., lime) to increase the pH following hydrolysis, for downstream operations. Furthermore, less acid and less base will also mean substantially less generation of waste salts (e.g., gypsum) that may otherwise require disposal.

[0146] In some embodiments, an additive may be included in amounts of about 0.1 wt% to 10 wt% or more to increase cellulose viscosity. Exemplary additives include ammonia, ammonia hydroxide, urea, anthraquinone, magnesium oxide, magnesium hydroxide, sodium hydroxide, and their derivatives.

[0147] The cooking is performed in one or more stages using batch or continuous digestors. Solid and liquid may flow cocurrently or countercurrently, or in any other flow pattern that achieves the desired fractionation. The cooking reactor may be internally agitated, if desired.

[0148] Depending on the lignocellulosic material to be processed, the cooking conditions are varied, with temperatures from about 65°C to 190°C, for example 75°C, 85°C, 95°C, 105°C, 115°C, 125°C, 130°C, 135°C, 140°C, 145°C, 150°C, 155°C, 165°C or 170°C, and corresponding pressures from about 1 atmosphere to about 15 atmospheres in the liquid or vapor phase. The cooking time of one or more stages may be selected from about 15 minutes to about 720 minutes, such as about 30, 45, 60, 90, 120, 140, 160, 180, 250, 300, 360, 450, 550, 600, or 700 minutes. Generally, there is an inverse relationship between the temperature used during the digestion step and the time needed to obtain good fractionation of the biomass into its constituent parts.

[0149] The cooking liquor to lignocellulosic material ratio may be selected from about 1 to about 10, such as about 2, 3, 4, 5, or 6. In some embodiments, biomass is digested in a pressurized vessel with low liquor volume (low ratio of cooking liquor to lignocellulosic material), so that the cooking space is filled with ethanol and sulfur dioxide vapor in equilibrium with moisture. The cooked biomass is washed in alcohol-rich solution to recover lignin and dissolved hemicelluloses, while the remaining pulp is further processed. In some embodiments, the process of fractionating lignocellulosic material comprises vapor-phase cooking of lignocellulosic material with aliphatic alcohol (or other solvent for lignin), water, and sulfur dioxide. See, for example, U.S. Patent Nos. 8,038,842 and 8,268,125.

[0150] A portion or all of the sulfur dioxide may be present as sulfurous acid in the extract liquor. In certain embodiments, sulfur dioxide is generated in situ by introducing sulfurous acid, sulfite ions, bisulfite ions, combinations thereof, or a salt of any of the foregoing. Excess sulfur dioxide, following hydrolysis, may be recovered and reused. In some embodiments, sulfur dioxide is saturated in water (or aqueous solution, optionally with an alcohol) at a first temperature, and the hydrolysis is then carried out at a second, generally higher, temperature. In some embodiments, sulfur dioxide is sub-saturated. In some embodiments, sulfur dioxide is supersaturated. In some embodiments, sulfur dioxide concentration is selected to achieve a certain degree of lignin sulfonation, such as 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, or 10% sulfur content. SO2 reacts chemically with lignin to form stable lignosulfonic acids which may be present both in the solid and liquid phases.

[0151] The concentration of sulfur dioxide, additives, and aliphatic alcohol (or other solvent) in the solution and the time of cook may be varied to control the yield of cellulose and hemicellulose in the pulp. The concentration of sulfur dioxide and the time of cook may be varied to control the yield of lignin versus lignosulfonates in the hydrolysate. In some embodiments, the concentration of sulfur dioxide, temperature, and the time of cook may be varied to control the yield of fermentable sugars.

[0152] Once the desired amount of fractionation of both hemicellulose and lignin from the solid phase is achieved, the liquid and solid phases are separated. Conditions for the separation may be selected to minimize or enhance the reprecipitation of the extracted lignin on the solid phase. Minimizing lignin reprecipitation is favored by conducting separation or washing at a temperature of at least the glass-transition temperature of lignin (about 120°C); conversely, enhancing lignin reprecipitation is favored by conducting separation or washing at a temperature less than the glass-transition temperature of lignin.

[0153] The physical separation can be accomplished either by transferring the entire mixture to a device that can carry out the separation and washing, or by removing only one of the phases from the reactor while keeping the other phase in place. The solid phase can be physically retained by appropriately sized screens through which liquid can pass. The solid is retained on the screens and can be kept there for successive solid-wash cycles. Alternately, the liquid may be retained and solid phase forced out of the reaction zone, with centrifugal or other forces that can effectively transfer the solids out of the slurry. In a continuous system, countercurrent flow of solids and liquid can accomplish the physical separation.

[0154] The recovered solids normally will contain a quantity of lignin and sugars, some of which can be removed easily by washing. The washing-liquid composition can be the same as or different than the liquor composition used during fractionation. Multiple washes may be performed to increase effectiveness. Preferably, one or more washes are performed with a composition including a solvent for lignin, to remove additional lignin from the solids, followed by one or more washes with water to displace residual solvent and sugars from the solids. Recycle streams, such as from solvent-recovery operations, may be used to wash the solids.

[0155] After separation and washing as described, a solid phase and at least one liquid phase are obtained. The solid phase contains substantially undigested cellulose. A single liquid phase is usually obtained when the solvent and the water are miscible in the relative proportions that are present. In that case, the liquid phase contains, in dissolved form, most of the lignin originally in the starting lignocellulosic material, as well as soluble monomeric and oligomeric sugars formed in the hydrolysis of any hemicellulose that may have been present. Multiple liquid phases tend to form when the solvent and water are wholly or partially immiscible. The lignin tends to be contained in the liquid phase that contains most of the solvent. Hemicellulose hydrolysis products tend to be present in the liquid phase that contains most of the water.

[0156] In some embodiments, hydrolysate from the cooking step is subjected to pressure reduction. Pressure reduction may be done at the end of a cook in a batch digestor, or in an external flash tank after extraction from a continuous digestor, for example. The flash vapor from the pressure reduction may be collected into a cooking liquor make-up vessel. The flash vapor contains substantially all the unreacted sulfur dioxide which may be directly dissolved into new cooking liquor. The cellulose is then removed to be washed and further treated as desired.

[0157] A process washing step recovers the hydrolysate from the cellulose. The washed cellulose is pulp that may be used for various purposes (e.g., paper or nanocellulose production). The weak hydrolysate from the washer continues to the final reaction step; in a continuous digestor this weak hydrolysate may be combined with the extracted hydrolysate from the external flash tank. In some embodiments, washing and/or separation of hydrolysate and cellulose-rich solids is conducted at a temperature of at least about 100°C, 110°C, or 120°C. The washed cellulose may also be used for glucose production via cellulose hydrolysis with enzymes or acids.

[0158] In another reaction step, the hydrolysate may be further treated in one or multiple steps to hydrolyze the oligomers into monomers. This step may be conducted before, during, or after the removal of solvent and sulfur dioxide. The solution may or may not contain residual solvent (e.g. alcohol). In some embodiments, sulfur dioxide is added or allowed to pass through to this step, to assist hydrolysis. In these or other embodiments, an acid such as sulfurous acid or sulfuric acid is introduced to assist with hydrolysis. In some embodiments, the hydrolysate is autohydrolyzed by heating under pressure. In some embodiments, no additional acid is introduced, but lignosulfonic acids produced during the initial cooking are effective to catalyze hydrolysis of hemicellulose oligomers to monomers. In various embodiments, this step utilizes sulfur dioxide, sulfurous acid, sulfuric acid at a concentration of about 0.01 wt% to 30 wt%, such as about 0.05 wt%, 0.1 wt%, 0.2 wt%, 0.5 wt%, 1 wt%, 2 wt%, 5 wt%, 10 wt%, or 20 wt%. This step may be carried out at a temperature from about 100°C to 220°C, such as about 110°C, 120°C, 130°C, 140°C, 150°C, 160°C, 170°C, 180°C, 190°C, 200°C, or 210°C. Heating may be direct or indirect to reach the selected temperature.

[0159] The reaction step produces fermentable sugars which can then be concentrated by evaporation to a fermentation feedstock. Concentration by evaporation may be accomplished before, during, or after the treatment to hydrolyze oligomers. The final reaction step may optionally be followed by steam stripping of the resulting hydrolysate to remove and recover sulfur dioxide and alcohol, and for removal of potential fermentation-inhibiting side products. The evaporation process may be under vacuum or pressure, from about 0.1 atmospheres (0.01 MPa) to about 10 atmospheres (1.01 MPa), such as about 0.1 atm (0.01 MPa), 0.3 atm (0.03 MPa), 0.5 atm (0.05 MPa), 1.0 atm (0.10 MPa), 1.5 atm (0.15 MPa), 2 atm (0.20 MPa), 4 atm (0.41 MPa), 6 atm (0.61 MPa), or 8 atm (0.81 MPa).

[0160] Recovering and recycling the sulfur dioxide may utilize separations such as, but not limited to, vapor-liquid disengagement (e.g. flashing), steam stripping, extraction, or combinations or multiple stages thereof. Various recycle ratios may be practiced, such as about 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 0.95, or more. In some embodiments, about 90-99% of initially charged SO2 is readily recovered by distillation from the liquid phase, with the remaining 1-10% (e.g., about 3-5%) of the SO2 primarily bound to dissolved lignin in the form of lignosulfonates.

[0161] In a preferred embodiment, the evaporation step utilizes an integrated alcohol stripper and evaporator. Evaporated vapor streams may be segregated so as to have different concentrations of organic compounds in different streams. Evaporator condensate streams may be segregated so as to have different concentrations of organic compounds in different streams. Alcohol may be recovered from the evaporation process by condensing the exhaust vapor and returning to the cooking liquor make-up vessel in the cooking step. Clean condensate from the evaporation process may be used in the washing step.

[0162] In some embodiments, an integrated alcohol stripper and evaporator system is employed, wherein aliphatic alcohol is removed by vapor stripping, the resulting stripper product stream is concentrated by evaporating water from the stream, and evaporated vapor is compressed using vapor compression and is reused to provide thermal energy.

[0163] The hydrolysate from the evaporation and final reaction step contains mainly fermentable sugars but may also contain lignin depending on the location of lignin separation in the overall process configuration. The hydrolysate may be concentrated to a concentration of about 5 wt% to about 60 wt% solids, such as about 10 wt%, 15 wt%, 20 wt%, 25 wt%, 30 wt%, 35 wt%, 40 wt%, 45 wt%, 50 wt% or 55 wt% solids. The hydrolysate contains fermentable sugars.

[0164] Fermentable sugars are defined as hydrolysis products of cellulose, galactoglucomannan, glucomannan, arabinoglucuronoxylans, arabinogalactan, and glucuronoxylans into their respective short-chained oligomers and monomer products, i.e., glucose, mannose, galactose, xylose, and arabinose. The fermentable sugars may be recovered in purified form, as a sugar slurry or dry sugar solids, for example. Any known technique may be employed to recover a slurry of sugars or to dry the solution to produce dry sugar solids.

[0165] In some embodiments, the fermentable sugars are fermented to produce biochemicals or biofuels such as (but by no means limited to) ethanol, isopropanol, acetone, 1-butanol, isobutanol, lactic acid, succinic acid, or any other fermentation products. Some amount of the fermentation product may be a microorganism or enzymes, which may be recovered if desired.

[0166] When the fermentation will employ bacteria, such as Clostridia bacteria, it is preferable to further process and condition the hydrolysate to raise pH and remove residual SO2 and other fermentation inhibitors. The residual SO2 (i.e., following removal of most of it by stripping) may be catalytically oxidized to convert residual sulfite ions to sulfate ions by oxidation. This oxidation may be accomplished by adding an oxidation catalyst, such as FeSO4·7H2O, that oxidizes sulfite ions to sulfate ions, which is a well-known practice for fermentation to acetone/butanol/ethanol (ABE). Preferably, the residual SO2 is reduced to less than about 100 ppm, 50 ppm, 25 ppm, 10 ppm, 5 ppm, or 1 ppm.

[0167] In some embodiments, the process further comprises recovering the lignin as a co-product. The sulfonated lignin may also be recovered as a co-product. In certain embodiments, the process further comprises combusting or gasifying the sulfonated lignin, recovering sulfur contained in the sulfonated lignin in a gas stream comprising reclaimed sulfur dioxide, and then recycling the reclaimed sulfur dioxide for reuse.

[0168] The process lignin separation step is for the separation of lignin from the hydrolysate and can be located before or after the final reaction step and evaporation. If located after, then lignin will precipitate from the hydrolysate since alcohol has been removed in the evaporation step. The remaining water-soluble lignosulfonates may be precipitated by converting the hydrolysate to an alkaline condition (pH higher than 7) using, for example, an alkaline earth oxide, preferably calcium oxide (lime). The combined lignin and lignosulfonate precipitate may be filtered. The lignin and lignosulfonate filter cake may be dried as a co-product or burned or gasified for energy production. The hydrolysate from filtering may be recovered and sold as a concentrated sugar solution product or further processed in a subsequent fermentation or other reaction step.

[0169] Native (non-sulfonated) lignin is hydrophobic, while lignosulfonates are hydrophilic. Hydrophilic lignosulfonates may have less propensity to clump, agglomerate, and stick to surfaces. Even lignosulfonates that do undergo some condensation and increase of molecular weight, will still have an HSO3 group that will contribute some solubility (hydrophilic).

[0170] In some embodiments, the soluble lignin precipitates from the hydrolysate after solvent has been removed in the evaporation step. In some embodiments, reactive lignosulfonates are selectively precipitated from hydrolysate using excess lime (or other base, such as ammonia) in the presence of aliphatic alcohol. In some embodiments, hydrated lime is used to precipitate lignosulfonates. In some embodiments, part of the lignin is precipitated in reactive form and the remaining lignin is sulfonated in water-soluble form.

[0171] The process fermentation and distillation steps are intended for the production of fermentation products, such as alcohols or organic acids. After removal of cooking chemicals and lignin, and further treatment (oligomer hydrolysis), the hydrolysate contains mainly fermentable sugars in water solution from which any fermentation inhibitors have been preferably removed or neutralized. The hydrolysate is fermented to produce dilute alcohol or organic acids, from 1 wt% to 20 wt% concentration. The dilute product is distilled or otherwise purified as is known in the art.

[0172] When alcohol is produced, such as ethanol, some of it may be used for cooking liquor makeup in the process cooking step. Also, in some embodiments, a distillation column stream, such as the bottoms, with or without evaporator condensate, may be reused to wash cellulose. In some embodiments, lime may be used to dehydrate product alcohol. Side products may be removed and recovered from the hydrolysate. These side products may be isolated by processing the vent from the final reaction step and/or the condensate from the evaporation step. Side products include furfural, hydroxymethyl furfural (HMF), methanol, acetic acid, and lignin-derived compounds, for example.

[0173] The glucose may be fermented to an alcohol, an organic acid, or another fermentation product. The glucose may be used as a sweetener or isomerized to enrich its fructose content. The glucose may be used to produce baker's yeast. The glucose may be catalytically or thermally converted to various organic acids and other materials.

[0174] When hemicellulose is present in the starting biomass, all or a portion of the liquid phase contains hemicellulose sugars and soluble oligomers. It is preferred to remove most of the lignin from the liquid, as described above, to produce a fermentation broth which will contain water, possibly some of the solvent for lignin, hemicellulose sugars, and various minor components from the digestion process. This fermentation broth can be used directly, combined with one or more other fermentation streams, or further treated. Further treatment can include sugar concentration by evaporation; addition of glucose or other sugars (optionally as obtained from cellulose saccharification); addition of various nutrients such as salts, vitamins, or trace elements; pH adjustment; and removal of fermentation inhibitors such as acetic acid and phenolic compounds. The choice of conditioning steps should be specific to the target product(s) and microorganism(s) employed.

[0175] In some embodiments, hemicellulose sugars are not fermented but rather are recovered and purified, stored, sold, or converted to a specialty product. Xylose, for example, can be converted into xylitol.

[0176] A lignin product can be readily obtained from a liquid phase using one or more of several methods. One simple technique is to evaporate off all liquid, resulting in a solid lignin-rich residue. This technique would be especially advantageous if the solvent for lignin is water-immiscible. Another method is to cause the lignin to precipitate out of solution. Some of the ways to precipitate the lignin include (1) removing the solvent for lignin from the liquid phase, but not the water, such as by selectively evaporating the solvent from the liquid phase until the lignin is no longer soluble; (2) diluting the liquid phase with water until the lignin is no longer soluble; and (3) adjusting the temperature and/or pH of the liquid phase. Methods such as centrifugation can then be utilized to capture the lignin. Yet another technique for removing the lignin is continuous liquid-liquid extraction to selectively remove the lignin from the liquid phase, followed by removal of the extraction solvent to recover relatively pure lignin.

[0177] Lignin produced in accordance with the invention can be used as a fuel. As a solid fuel, lignin is similar in energy content to coal. Lignin can act as an oxygenated component in liquid fuels, to enhance octane while meeting standards as a renewable fuel. The lignin produced herein can also be used as polymeric material, and as a chemical precursor for producing lignin derivatives. The sulfonated lignin may be sold as a lignosulfonate product, or burned for fuel value.

[0178] Systems configured for carrying out the disclosed processes, and compositions produced therefrom, are also disclosed herein. Any stream generated by the disclosed processes may be partially or completed recovered, purified or further treated, and/or marketed or sold.

[0179] Certain nanocellulose-containing products provide high transparency, good mechanical strength, and/or enhanced gas (e.g., O2 or CO2) barrier properties, for example. Certain nanocellulose-containing products containing hydrophobic nanocellulose materials provided herein may be useful as anti-wetting and anti-icing coatings, for example.

[0180] Due to the low mechanical energy input, nanocellulose-containing products produced by the methods provided herein may be characterized by fewer defects that normally result from intense mechanical treatment.

[0181] Nanocellulose-containing products disclosed herein may have applications for sensors, catalysts, antimicrobial materials, current carrying and energy storage capabilities. Cellulose nanocrystals have the capacity to assist in the synthesis of metallic and semiconducting nanoparticle chains.

[0182] Composites containing nanocellulose and a carbon-containing material, such as (but not limited to) lignin, graphite, graphene, or carbon aerogels are disclosed herein.

[0183] Cellulose nanocrystals may be coupled with the stabilizing properties of surfactants and exploited for the fabrication of nanoarchitectures of various semiconducting materials.

[0184] The reactive surface of -OH side groups in nanocellulose facilitates grafting chemical species to achieve different surface properties. Surface functionalization allows the tailoring of particle surface chemistry to facilitate self-assembly, controlled dispersion within a wide range of matrix polymers, and control of both the particle-particle and particle-matrix bond strength. Composites may be transparent, have tensile strengths greater than cast iron, and have 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, pharmaceuticals, drug delivery, fibers and textiles, templates for electronic components, separation membranes, batteries, supercapacitors, electroactive polymers, and many others.

[0185] Other nanocellulose applications include reinforced polymers, high-strength spun fibers and textiles, advanced composite materials, films for barrier and other properties, additives for coatings, paints, lacquers and adhesives, switchable optical devices, pharmaceuticals and drug delivery systems, bone replacement and tooth repair, improved paper, packaging and building products, additives for foods and cosmetics, catalysts, and hydrogels.

[0186] Aerospace and transportation composites may benefit from high crystallinity. Automotive applications include nanocellulose composites with polypropylene, polyamide (e.g. Nylons), or polyesters (e.g. PBT).

[0187] Nanocellulose materials disclosed herein are suitable as strength-enhancing additives for renewable and biodegradable composites. The cellulosic nanofibrillar structures may function as a binder between two organic phases for improved fracture toughness and prevention of crack formation for application in packaging, construction materials, appliances, and renewable fibers.

[0188] Nanocellulose materials disclosed herein are suitable as transparent and dimensional stable strength-enhancing additives and substrates for application in flexible displays, flexible circuits, printable electronics, and flexible solar panels. Nanocellulose is incorporated into the substrate-sheets are formed by vacuum filtration, dried under pressure and calandered, for example. In a sheet structure, nanocellulose acts as a glue between the filler aggregates. The formed calandered sheets are smooth and flexible.

[0189] Nanocellulose materials disclosed herein are suitable for composite and cement additives allowing for crack reduction and increased toughness and strength. Foamed, cellular nanocellulose-concrete hybrid materials allow for lightweight structures with increased crack reduction and strength.

[0190] Strength enhancement with nanocellulose increases both the binding area and binding strength for application in high strength, high bulk, high filler content paper and board with enhanced moisture and oxygen barrier properties. The pulp and paper industry in particular may benefit from nanocellulose materials disclosed herein.

[0191] Nanofibrillated cellulose nanopaper has a higher density and higher tensile mechanical properties than conventional paper. It can also be optically transparent and flexible, with low thermal expansion and excellent oxygen barrier characteristics. The functionality of the nanopaper can be further broadened by incorporating other entities such as carbon nanotubes, nanoclay or a conductive polymer coating.

[0192] Porous nanocellulose may be used for cellular bioplastics, insulation and plastics and bioactive membranes and filters. Highly porous nanocellulose materials are generally of high interest in the manufacturing of filtration media as well as for biomedical applications, e.g., in dialysis membranes.

[0193] Nanocellulose materials disclosed herein are suitable as coating materials as they are expected to have a high oxygen barrier and affinity to wood fibers for application in food packaging and printing papers.

[0194] Nanocellulose materials disclosed herein are suitable as additives to improve the durability of paint, protecting paints and varnishes from attrition caused by UV radiation.

[0195] Nanocellulose materials disclosed herein are suitable as thickening agents in food and cosmetics products. Nanocellulose can be used as thixotropic, biodegradable, dimensionally stable thickener (stable against temperature and salt addition). Nanocellulose materials disclosed herein are suitable as a Pickering stabilizer for emulsions and particle stabilized foam.

[0196] The large surface area of these nanocellulose materials in combination with their biodegradability makes them attractive materials for highly porous, mechanically stable aerogels. Nanocellulose aerogels display a porosity of 95% or higher, and they are ductile and flexible.

[0197] Drilling fluids are fluids used in drilling in the natural gas and oil industries, as well as other industries that use large drilling equipment. The drilling fluids are used to lubricate, provide hydrostatic pressure, and to keep the drill cool, and the hole as clean as possible of drill cuttings. Nanocellulose materials disclosed herein are suitable as additives to these drilling fluids.

EXAMPLES


Example 1: Production of cellulose nanofibrils and cellulose nanocrystals.



[0198] Eucalyptus chips (30 wet grams; 46 wt% moisture) were cooked in a 250-mL reactor in a hot oil bath with 12 wt% SO2, 56 wt% ethanol, and a liquor-to-biomass ratio of 6. The fractionation chemicals solution was composed of 49.2 g 95 wt% ethanol solution, 23.5 g distilled water, and 10.4 g SO2. Time and temperature were varied to study the effect on degree of polymerization, particle morphology, and mechanical energy consumption for the final fibrillization step.

[0199] The following conditions were studied:

Fractionation temperature 145°C, fractionation time 45 min

Fractionation temperature 145°C, fractionation time 60 min

Fractionation temperature 165°C, fractionation time 15 min

Fractionation temperature 165°C, fractionation time 30 min

Fractionation temperature 165°C, fractionation time 45 min

Fractionation temperature 165°C, fractionation time 60 min

Fractionation temperature 165°C, fractionation time 75 min

Fractionation temperature 165°C, fractionation time 90 min



[0200] Following fractionation, the pulp (cellulose-rich solids) was washed with 100 g of 50 wt% ethanol/water (two times) at 60°C followed by 500 mL distilled water (two times) at room temperature. The washed pulp (washed cellulose-rich solids) was analyzed for Kappa number and degree of polymerization.

[0201] The washed pulp was then bleached using a DEpD sequence. For example, the washed pulp after the treatment at 145°C and 45 min had a Kappa number of 8. In the first bleaching stage, chlorine dioxide was added at 0.65 wt% charge on pulp to a 10% pulp suspension. In the second stage, sodium hydroxide was added at a 2.00% charge on pulp to a 12% pulp suspension along with hydrogen peroxide at a 0.5% charge on pulp. In the final stage, chlorine dioxide was added at 1% charge on pulp to a 10% pulp suspension. The bleached pulp was analyzed for yield and degree of polymerization. It was found that the measured degree of polymerization increased slightly after bleaching, as small cellulose fragments are removed.

[0202] For each treatment condition, a 0.65 wt% suspension of bleached pulp was made and passed through a M-110EH-30 Microfluidizer Processor from Microfluidics (Westwood, Massachusetts, US) for up to 30 passes using a combination of interaction chambers with internal diameters of 87 µm, 200 µm, and 400 µm, depending on level of size reduction required. A constant pressure up to 30 kpsi (207 MPa) was supplied at a constant rate to the product stream. The interaction chamber's fixed-geometry microchannels accelerate the product stream to high velocity. High shear and impact forces reduce size of particles as the high velocity product stream impinges on itself and the wear resistant surfaces (polycystalline diamond). A heat exchanger regulates temperature. Samples were taken at each pass for observation of particle morphology by SEM and TEM.

[0203] For instance, using the material produced at 145°C and 45 min fractionation time, a single pass through the 400 µm chamber resulted in broken fibers. A single pass through the 200 µm and 87 µm chambers resulted in fibers and fibrils. Five passes through the 200 µm and 87 µm chambers resulted in fibrils, as shown by SEM. More passes through chambers were done to show increased fibrillization. This result demonstrated that cellulose nanofibrils can be produced starting with biomass fractionation 145°C, 45 min, and 12% SO2 in water and a solvent for lignin. Energy consumption was estimated to be about 860 kWh/ton (0.948 kWh/kg).

[0204] Using the material produced at 165°C and 15 min fractionation time, a single pass through the 400 µm and 200 µm chambers resulted in fibers and fibrils. Five or ten passes through the 200 µm and 87 µm chambers resulted in fibrils and whiskers. Thirty passes through the 200 µm and 87 µm chambers resulted in primarily whiskers, as observed by SEM.

[0205] Using the material produced at 165°C and 90 min fractionation time, five passes through the 200 µm chamber resulted in crystals. Five or thirty passes through the 200 µm and 87 µm chambers resulted in crystals. This result demonstrated that cellulose nanocrystals can be produced starting with biomass fractionation 165°C, 90 min, and 12% SO2 in water and a solvent for lignin. Energy consumption was estimated to be about 370 kWhr/ton (0.408 kWh/kg), although it is believed less energy may be necessary with fewer passes through the interaction chambers.

[0206] FIG. 5 is a graph showing experimental degree of polymerization of nanocellulose versus fractionation time, in this Example 1. FIG. 6 is a graph showing experimental Kappa number of nanocellulose versus fractionation time, in this Example 1. SEM images confirmed that DP is a good predictor for nanomaterial type/length after fibrillization, including mixtures of nanofibrils and nanocrystals.

[0207] FIG. 7 is an exemplary scanning-electron microscopy image of cellulose nanofibrils. FIG. 8 is an exemplary scanning electron microscopy image of cellulose nanocrystals. FIG. 9 is an exemplary transmission electron microscopy image of cellulose nanocrystals (whiskers).

Example 2: Production of nanocellulose materials from softwood.



[0208] Fractionation of softwood is carried out at 165°C for 60 minutes, with 12 wt% SO2, 56 wt% ethanol, and a liquor-to-biomass ratio of 6. Mechanical treatment includes ultrasonication for 10 minutes at 360 W, to generate nanocellulose. The crystallinity of the cellulose-rich solids is estimated to be 86%. The crystallinity of the nanocellulose is estimated to be 86%, showing high crystallinity of both the precursor material and the nanocellulose, and little or no loss of crystallinity during mechanical treatment. The nanocellulose particles are characterized by an average width of about 20 nm and length range from about 300 nm about 1000 nm or more.

Example 3: Production of nanocellulose materials from sugarcane straw.



[0209] Fractionation of sugarcane straw is carried out at 165°C for 60 minutes, with 12 wt% SO2, 56 wt% ethanol, and a liquor-to-biomass ratio of 6. Mechanical treatment includes ultrasonication for 10 minutes at 360 W, to generate nanocellulose. The crystallinity of the cellulose-rich solids is estimated to be above 80%. The crystallinity of the nanocellulose is estimated to be above 80%, showing high crystallinity of both the precursor material and the nanocellulose, and little or no loss of crystallinity during mechanical treatment. The nanocellulose particles are characterized by an average width of about 20 nm and length range from about 300 nm about 1000 nm or more.

Example 4: Production of lignin-boated cellulose nanofibrils.



[0210] Eucalyptus chips (30 wet grams; 46 wt% moisture) were cooked in a 250 mL reactor in a hot oil bath at 145°C for 45 minutes, with 12 wt% SO2, 56 wt% ethanol, and a liquor-to-biomass ratio of 6. The fractionation chemicals solution was composed of 49.2 g 95 wt% ethanol solution, 23.5 g distilled water, and 10.4 g SO2. The pulp was washed with 500 mL distilled water (two times) at room temperature. The dissolved unsulfonated lignin is insoluble in water and precipitates on the fibers surface. The measured Kappa number is about 14.5, compared to a Kappa number of 8.0 when washing with ethanol/water is performed (FIG. 6). That is, washing with water only aids in lignin deposition, which is desirable in this case.

[0211] The resulting material was microfluidized at 0.65 wt%, up to 20 passes, as described above. The nanocellulose product was recovered as a dilute solids suspension.


Claims

1. A process for producing a nanocellulose material or a nanocellulose-containing product comprising nanocellulose particles having at least one length dimension of from 0.01nm to 1000nm, said process comprising:

(a) providing a lignocellulosic biomass feedstock;

(b) fractionating said feedstock in the presence of an acid, preferably an acid selected from the group consisting of sulfur dioxide, sulfurous acid, sulfur trioxide, sulfuric acid, lignosulfonic acid, and combinations thereof, and more preferably an acid of sulfur dioxide, a solvent for lignin, and water, to generate cellulose-rich solids and a liquid containing hemicellulose and lignin;

(c) mechanically treating said cellulose-rich solids with a total mechanical energy of less than about 1000 kilowatt-hours per ton (1.102 kWh/kg) of said cellulose-rich solids to form cellulose fibrils and/or cellulose crystals, preferably wherein said cellulose-rich solids are treated with a total mechanical energy of less than about 500 kilowatt-hours per ton (0.551 kWh/kg) of said cellulose-rich solids, and more preferably with a total mechanical energy of from about 100 kilowatt-hours(0.110 kWh/kg) to about 400 kilowatt-hours per ton (0.441 kWh/kg) of said cellulose-rich solids, thereby generating a nanocellulose material having a crystallinity of at least 60%, preferably of at least 70%, 80% or 85%; and

(d)

(i) recovering said nanocellulose material; or

(ii) incorporating at least a portion of said nanocellulose material into a nanocellulose-containing product, preferably wherein said nanocellulose-containing product consists essentially of said nanocellulose material.


 
2. The process of claim 1, wherein step (c) further comprises treatment of said cellulose-rich solids with one or more enzymes, with one or more acids, preferably selected from the group consisting of sulfur dioxide, sulfurous acid, lignosulfonic acid, acetic acid, formic acid, and combinations thereof, or with heat.
 
3. The process of claim 1, wherein step (c) does not employ any enzymes or acids.
 
4. The process of claim 1, said process further comprising bleaching said cellulose-rich solids prior to step (c) and/or as part of step (c), or bleaching said nanocellulose material during step (c) and/or following step (c).
 
5. The process of claim 1, wherein said nanocellulose material comprises nanofibrillated cellulose and/or nanocrystalline cellulose.
 
6. The process of claim 1, wherein said nanocellulose material is characterized by an average degree of polymerization from about 100 to about 1500, preferably from about 300 to about 700 or from about 150 to about 250.
 
7. The process of claim 1, said process further comprising hydrolyzing amorphous cellulose into glucose in step (b) and/or step (c), recovering said glucose, and optionally fermenting said glucose to a fermentation product, said process further comprising recovering, fermenting, or further treating hemicellulosic sugars derived from said hemicellulose, preferably fermenting said hemicellulosic sugars to produce a monomer or precursor thereof; polymerizing said monomer to produce a polymer; and combining said polymer and said nanocellulose material to form a polymer-nanocellulose composite, and/or said process further comprising recovering, combusting, or further treating said lignin.
 
8. The process of claim 1, wherein said nanocellulose material is at least partially hydrophobic via deposition of at least some of said lignin onto a surface of said cellulose-rich solids during step (b), or onto a surface of said nanocellulose material during step (c) or step (d).
 
9. The process of claim 1, said process further comprising chemically converting said nanocellulose material to one or more nanocellulose derivatives, preferably selected from the group consisting of nanocellulose esters, nanocellulose ethers, nanocellulose ether esters, alkylated nanocellulose compounds, cross-linked nanocellulose compounds, acid-functionalized nanocellulose compounds, base-functionalized nanocellulose compounds, and combinations thereof.
 
10. The process of claim 1, wherein said acid is sulfur dioxide having a concentration from about 10 wt% to about 50 wt%, preferably from about 12 wt% to about 30wt%, the crystallinity of said cellulose-rich solids is at least 70%, the fractionation temperature is from about 130°C to about 200°C, preferably from about 140°C to about 170°C, and the fractionation time is from about 30 minutes to about 4 hours, preferably from about 1 hour to about 2 hours; and said nanocellulose material has a crystallinity of at least 70%.
 
11. The process of claim 10, wherein during step (b), a portion of said lignin deposits onto a surface of said cellulose-rich solids, thereby rendering said cellulose-rich solids at least partially hydrophobic.
 
12. The process of any one of claims 1, 5 or 6, wherein said nanocellulose material is hydrophobic, and wherein in step (b) a portion of said lignin deposits onto a surface of said cellulose-rich solids, thereby rendering said cellulose-rich solids at least partially hydrophobic, and in step (c) a hydrophobic nanocellulose material having a crystallinity of at least 60% is generated.
 
13. The process of claim 12, said process further comprising chemically modifying said lignin to increase hydrophobicity of said nanocellulose material.
 
14. The process of claim 1, wherein step (d)(ii) comprises forming a structural object that includes said nanocellulose material, or a derivative thereof, forming a foam or aerogel that includes said nanocellulose material, or a derivative thereof, forming a film comprising said nanocellulose material, or a derivative thereof, preferably an optically transparent and flexible film, or forming a coating or coating precursor comprising said nanocellulose material, or a derivative thereof, preferably wherein said nanocellulose material is at least partially hydrophobic via deposition of at least some of said lignin onto a surface of said cellulose-rich solids during step (b), or wherein said nanocellulose material is at least partially hydrophobic via deposition of at least some of said lignin onto a surface of said nanocellulose material during step (c) or step (d) or wherein step (d)(ii) comprises combining said nanocellulose material, or a derivative thereof, with one or more other materials, preferably with a polymer selected from polyolefins, polyesters, polyurethanes, polyamides, or combinations thereof, or with carbon to form a composite.
 
15. The process of claim 1, wherein said nanocellulose-containing product is configured electrochemically for carrying or storing an electrical current or voltage, is incorporated into a filter, membrane, or other separation device, is incorporated as an additive into a coating, paint, or adhesive, is configured as a catalyst, catalyst substrate, or co-catalyst, is incorporated as a cement additive, is a paper coating, is incorporated as a thickening agent or rheological modifier, or is incorporated as an additive in a drilling fluid, preferably in an oil recovery fluid and/or a gas recovery fluid.
 


Ansprüche

1. Verfahren zur Herstellung eines Nanozellulosematerials oder eine Nanozellulose enthaltenden Produkts, das Nanozellulosepartikel umfasst, die zumindest eine Längenausdehnung von 0,01nm bis 1000nm aufweisen, wobei das Verfahren umfasst:

(a) Bereitstellen einer Biomasse aus Lignozellulose als Ausgangsmaterial;

(b) Fraktionieren des Ausgangsmaterials in Gegenwart einer Säure, vorzugsweise einer Säure, die ausgewählt wird aus der Gruppe, die aus Schwefeldioxid, schwefliger Säure, Schwefeltrioxid, Schwefelsäure, Ligninsulfonsäure und Kombinationen davon, und bevorzugter einer Säure von Schwefeldioxid, eines Lösungsmittels für Lignin, und Wasser besteht, um Zellulose-reiche Feststoffe und eine Hemizellulose und Lignin enthaltende Flüssigkeit zu erzeugen;

(c) Mechanisches Behandeln der Zellulose-reichen Feststoffe mit einer mechanischen Gesamtenergie von unter etwa 1000 Kilowattstunden pro Tonne (1,102 kWh/kg) der Zellulose-reichen Feststoffe, um Zellulosefibrillen und/oder Zellulosekristalle zu bilden, wobei vorzugsweise die Zellulose-reichen Feststoffe mit einer mechanischen Gesamtenergie von unter etwa 500 Kilowattstunden pro Tonne (0,551 kWh/kg) der Zellulose-reichen Feststoffe, und bevorzugter mit einer mechanischen Gesamtenergie von etwa 100 Kilowattstunden (0,110 kWh/kg) bis etwa 400 Kilowattstunden pro Tonne (0,441 kWh/kg) der Zellulose-reichen Feststoffe behandelt werden, wobei dadurch ein Nanozellulosematerial erzeugt wird, das eine Kristallinität von zumindest 60%, bevorzugt von zumindest 70%, 80% oder 85% aufweist; und

(d)

(i) Rückgewinnen des Nanozellulosematerials; oder

(ii) Einarbeiten von zumindest einem Abschnitt des Nanozellulosematerials in eine Nanozellulose enthaltendes Produkt, wobei vorzugsweise das Nanozellulose enthaltende Produkt im Wesentlichen aus dem Nanozellulosematerial besteht.


 
2. Verfahren nach Anspruch 1, wobei Schritt (c) weiter umfasst die Behandlung der Zellulose-reichen Feststoffe mit einem oder mehreren Enzymen, mit einer oder mehreren Säuren, vorzugsweise ausgewählt aus der Gruppe, die aus Schwefeldioxid, schwefliger Säure, Ligninsulfonsäure, Essigsäure, Ameisensäure und Kombinationen davon besteht, oder mit Hitze.
 
3. Verfahren nach Anspruch 1, wobei Schritt (c) keine Enzyme oder Säuren einsetzt.
 
4. Verfahren nach Anspruch 1, wobei das Verfahren weiter umfasst Bleichen der Zellulose-reichen Feststoffe vor Schritt (c) und/oder als Teil von Schritt (c), oder Bleichen des Nanozellulosematerials während Schritt (c) und/oder nach Schritt (c).
 
5. Verfahren nach Anspruch 1, wobei das Nanozellulosematerial nanofasrige Zellulose und/oder nanokristalline Zellulose umfasst.
 
6. Verfahren nach Anspruch 1, wobei das Nanozellulosematerial gekennzeichnet ist durch einen durchschnittlichen Polymerisationsgrad von etwa 100 bis etwa 1500, bevorzugt von etwa 300 bis etwa 700 oder von etwa 150 bis etwa 250.
 
7. Verfahren nach Anspruch 1, wobei das Verfahren weiter umfasst Hydrolysieren amorpher Zellulose zu Glukose in Schritt (b) und/oder Schritt (c), Rückgewinnen der Glukose und optionales Fermentieren der Glukose zu einem Fermentationsprodukt, wobei das Verfahren weiter umfasst Rückgewinnen, Fermentieren oder weiteres Behandeln hemizellulosischer Zucker, die von der Hemizellulose abgeleitet sind, bevorzugt Fermentieren der hemizellulosischen Zucker, um ein Monomer oder ein Vorprodukt davon herzustellen; Polymerisieren des Monomers, um ein Polymer herzustellen; und Kombinieren des Polymers und des Nanozellulosematerials, um einen Polymer-Nanozellulose Verbund zu bilden; und/oder das Verfahren weiter umfasst Rückgewinnen, Verbrennen oder weiteres Behandeln des Lignins.
 
8. Verfahren nach Anspruch 1, wobei das Nanozellulosematerial zumindest teilweise hydrophob ist durch Abscheidung von zumindest etwas Lignin auf einer Oberfläche der Zellulose-reichen Feststoffe während Schritt (b), oder auf einer Oberfläche des Nanozellulosematerials während Schritt (c) oder Schritt (d).
 
9. Verfahren nach Anspruch 1, wobei das Verfahren weiter umfasst chemisches Umwandeln des Nanozellulosematerials in ein oder mehrere Nanozellulosederivate, bevorzugt ausgewählt aus der Gruppe, die aus Nanozelluloseestern, Nanozelluloseäthern, Nanozelluloseätherestern, alkylierten Nanozelluloseverbindungen, vernetzten Nanozelluloseverbindungen, Säure-funktionalisierten Nanozelluloseverbindungen, Basen-funktionalisierten Nanozelluloseverbindungen und Kombinationen davon besteht.
 
10. Verfahren nach Anspruch 1, wobei die Säure Schwefeldioxid, die eine Konzentration von etwa 10 Gewichtsprozent bis etwa 50 Gewichtsprozent, bevorzugt von etwa 12 Gewichtsprozent bis etwa 30 Gewichtsprozent aufweist, ist, die Kristallinität der Zellulose-reichen Feststoffe zumindest 70% beträgt, die Fraktionierungstemperatur zwischen etwa 130°C und etwas 200°C, bevorzugt zwischen etwa 140°C und 170°C liegt, und die Fraktionierungszeit zwischen etwa 30 Minuten und etwa 4 Stunden, bevorzugt zwischen etwa 1 Stunde und etwa 2 Stunden liegt; und das Nanozellulosematerial eine Kristallinität von zumindest 70% aufweist.
 
11. Verfahren nach Anspruch 10, wobei während Schritt (b), ein Abschnitt des Lignins auf einer Oberfläche der Zellulose-reichen Feststoffe abscheidet, wobei dadurch die Zellulose-reichen Feststoffe zumindest teilweise hydrophob gemacht werden.
 
12. Verfahren nach einem der Ansprüche 1, 5 oder 6, wobei das Nanozellulosematerial hydrophob ist, und wobei in Schritt (b) ein Abschnitt des Lignins auf einer Oberfläche der Zellulose-reichen Feststoffe abscheidet, wobei dadurch die Zellulose-reichen Feststoffe zumindest teilweise hydrophob gemacht werden, und in Schritt (c) ein hydrophobes Nanozellulosematerial, das eine Kristallinität von zumindest 60% aufweist, erzeugt wird.
 
13. Verfahren nach Anspruch 12, wobei das Verfahren weiter umfasst chemisches Modifizieren des Lignins, um die Hydrophobizität des Nanozellulosematerials zu erhöhen.
 
14. Verfahren nach Anspruch 1, wobei Schritt (d)(ii) umfasst das Bilden eines strukturellen Objekts mit dem Nanozellulosematerial oder einem Derivat davon, Bilden eines Schaums oder eines festen Schaums, der das Nanozellulosematerial oder ein Derivat davon enthält, Bilden eines Films, der das Nanozellulosematerial oder ein Derivat davon umfasst, bevorzugt einen optisch transparenten und flexiblen Film, oder Bilden einer Beschichtung oder eines Beschichtungsvorprodukts, das das Nanozellulosematerial oder ein Derivat davon umfasst, bevorzugt wobei das Nanozellulosematerial zumindest teilweise hydrophob ist durch Abscheidung von zumindest etwas Lignin auf einer Oberfläche der Zellulose-reichen Feststoffe während Schritt (b), oder wobei das Nanozellulosematerial zumindest teilweise hydrophob ist durch Abscheidung von zumindest etwas Lignin auf einer Oberfläche des Nanozellulosematerial während Schritt (c) oder Schritt (d), oder wobei Schritt (d)(ii) umfasst Kombinieren des Nanozellulosematerials oder eines Derivats davon mit einem oder mehreren Materialien, bevorzugt mir einem Polymer ausgewählt aus der Gruppe, die aus Polyolefinen, Polyestern, Polyurethanen, Polyamiden oder einer Kombination davon besteht, oder mit Kohlenstoff, um einen Verbund zu bilden.
 
15. Verfahren nach Anspruch 1, wobei das Nanozellulose enthaltenden Produkt elektrochemisch eingerichtet ist, einen elektrischen Strom oder eine Spannung zu tragen oder zu speichern, eingebunden ist in einen Filter, eine Membran oder ein anderes Trennungsgerät, eingebunden ist als Zusatzstoff in eine Beschichtung, eine Farbe oder einen Klebstoff, eingerichtet ist als ein Katalysator, Katalysatorsubstrat oder Cokatalysator, eingebunden ist als ein Bindemittelzusatzstoff, eine Papierbeschichtung ist, eingebunden ist als ein Dickungsmittel oder als ein rheologisches Modifiziermittel, eingebunden ist als ein Zusatzstoff in einer Bohrflüssigkeit, bevorzugt in einer Ölrückgewinnungsflüssigkeit und/oder einer Gasrückgewinnungsflüssigkeit.
 


Revendications

1. Procédé de production d'un matériau de nanocellulose ou d'un produit contenant de la nanocellulose comprenant des particules de nanocellulose ayant au moins une dimension dans la longueur de 0,01 nm à 1000 nm, ledit procédé comprenant :

(a) la fourniture d'une charge de biomasse lignocellulosique ;

(b) le fractionnement de ladite charge en présence d'un acide, de préférence un acide sélectionné à partir du groupe constitué du dioxyde de soufre, de l'acide sulfureux, du trioxyde de soufre, de l'acide sulfurique, de l'acide lignosulfonique, et des combinaisons de ceux-ci, et plus de préférence un acide de dioxyde de soufre, un solvant pour la lignine, et de l'eau, pour générer des solides riches en cellulose et un liquide contenant de l'hémicellulose et de la lignine ;

(c) le traitement mécanique desdits solides riches en cellulose avec une énergie mécanique totale inférieure à environ 1000 kilowatts-heure par tonne (1,102 kWh/kg) desdits solides riches en cellulose pour former des fibrilles de cellulose et/ou des cristaux de cellulose, de préférence dans lequel lesdits solides riches en cellulose sont traités avec une énergie mécanique totale inférieure à environ 500 kilowatts-heure par tonne (0,551 kWh/kg) desdits solides riches en cellulose, et plus de préférence avec une énergie mécanique totale d'environ 100 kilowatts-heure par tonne (0,110 kWh/kg) à environ 400 kilowatts-heure par tonne (0,441 kWh/kg) desdits solides riches en cellulose, générant ainsi un matériau de nanocellulose ayant une cristallinité d'au moins 60 %, de préférence d'au moins 70 %, 80 % ou 85 % ; et

(d)

(i) la récupération dudit matériau de nanocellulose ; ou

(ii) l'incorporation d'au moins une portion dudit matériau de nanocellulose dans un produit contenant de la nanocellulose, de préférence dans lequel ledit produit contenant de la nanocellulose est essentiellement constitué dudit matériau de nanocellulose.


 
2. Procédé selon la revendication 1, dans lequel l'étape (c) comprend en outre le traitement desdits solides riches en cellulose avec une ou plusieurs enzymes, avec un ou plusieurs acides, de préférence sélectionnés à partir du groupe constitué du dioxyde de soufre, de l'acide sulfureux, de l'acide lignosulfonique, de l'acide acétique, de l'acide formique, et des combinaisons de ceux-ci, ou avec de la chaleur.
 
3. Procédé selon la revendication 1, dans lequel l'étape (c) n'utilise aucune enzyme ni aucun acide.
 
4. Procédé selon la revendication 1, ledit procédé comprenant en outre le blanchiment desdits solides riches en cellulose avant l'étape (c) et/ou en tant que partie de l'étape (c), ou le blanchiment dudit matériau de nanocellulose pendant l'étape (c) et/ou après l'étape (c).
 
5. Procédé selon la revendication 1, dans lequel ledit matériau de nanocellulose comprend de la cellulose en nanofibrilles et/ou de la cellulose en nanocristaux.
 
6. Procédé selon la revendication 1, dans lequel ledit matériau de nanocellulose est caractérisé par un degré de polymérisation moyen d'environ 100 à environ 1500, de préférence d'environ 300 à environ 700 ou d'environ 150 à environ 250.
 
7. Procédé selon la revendication 1, ledit procédé comprenant en outre l'hydrolyse de cellulose amorphe en glucose dans l'étape (b) et/ou l'étape (c), la récupération dudit glucose, et facultativement la fermentation dudit glucose en un produit de fermentation, ledit procédé comprenant en outre la récupération, la fermentation, ou le fait de traiter davantage les sucres hémicellulosiques issus de ladite hémicellulose, de préférence la fermentation desdits sucres hémicellulosiques pour produire un monomère ou un précurseur de ceux-ci ; la polymérisation dudit monomère pour produire un polymère ; et la combinaison dudit polymère et dudit matériau de nanocellulose pour former un composite polymère-nanocellulose, et/ou ledit procédé comprenant en outre la récupération, la combustion, ou le fait de traiter davantage ladite lignine.
 
8. Procédé selon la revendication 1, dans lequel ledit matériau de nanocellulose est au moins partiellement hydrophobe par dépôt d'au moins une partie de ladite lignine sur une surface desdits solides riches en cellulose pendant l'étape (b), ou sur une surface dudit matériau de nanocellulose pendant l'étape (c) ou l'étape (d).
 
9. Procédé selon la revendication 1, ledit procédé comprenant en outre la conversion chimique dudit matériau de nanocellulose en un ou plusieurs dérivés de nanocellulose, de préférence sélectionnés à partir du groupe constitué des esters de nanocellulose, des éthers de nanocellulose, des nanocellulose éther esters, des composés de nanocellulose alkylés, des composés de nanocellulose réticulés, des composés de nanocellulose à fonctionnalité acide, des composés de nanocellulose à fonctionnalité basique, et des combinaisons de ceux-ci.
 
10. Procédé selon la revendication 1, dans lequel ledit acide est le dioxyde de soufre ayant une concentration d'environ 10 % en poids à environ 50 % en poids, de préférence d'environ 12 % en poids à environ 30 % en poids, la cristallinité desdits solides riches en cellulose est d'au moins 70 %, la température de fractionnement est d'environ 130 °C à environ 200 °C, de préférence d'environ 140 °C à environ 170 °C, et le temps de fractionnement est d'environ 30 minutes à environ 4 heures, de préférence d'environ 1 heure à environ 2 heures; et ledit matériau de nanocellulose a une cristallinité d'au moins 70 %.
 
11. Procédé selon la revendication 10, dans lequel pendant l'étape (b), une portion de ladite lignine se dépose sur une surface desdits solides riches en cellulose, rendant ainsi lesdits solides riches en cellulose au moins partiellement hydrophobes.
 
12. Procédé selon l'une quelconque des revendications 1, 5 ou 6, dans lequel ledit matériau de nanocellulose est hydrophobe, et dans lequel dans l'étape (b) une portion de ladite lignine se dépose sur une surface desdits solides riches en cellulose, rendant ainsi lesdits solides riches en cellulose au moins partiellement hydrophobes, et dans l'étape (c) un matériau de nanocellulose hydrophobe ayant une cristallinité d'au moins 60 % est généré.
 
13. Procédé selon la revendication 12, ledit procédé comprenant en outre la modification chimique de ladite lignine pour augmenter l'hydrophobicité dudit matériau de nanocellulose.
 
14. Procédé selon la revendication 1, dans lequel l'étape (d) (ii) comprend la formation d'un objet structurel qui inclut ledit matériau de nanocellulose, ou un dérivé de celui-ci, la formation d'une mousse ou d'un aérogel qui inclut ledit matériau de nanocellulose, ou un dérivé de celui-ci, la formation d'un film comprenant ledit matériau de nanocellulose, ou un dérivé de celui-ci, de préférence un film optiquement transparent et souple, ou la formation d'un revêtement ou d'un précurseur de revêtement comprenant ledit matériau de nanocellulose, ou un dérivé de celui-ci, de préférence dans lequel ledit matériau de nanocellulose est au moins partiellement hydrophobe par dépôt d'au moins une partie de ladite lignine sur une surface desdits solides riches en cellulose pendant l'étape (b), ou dans lequel ledit matériau de nanocellulose est au moins partiellement hydrophobe par dépôt d'au moins une partie de ladite lignine sur une surface dudit matériau de nanocellulose pendant l'étape (c) ou l'étape (d) ou dans lequel l'étape (d) (ii) comprend la combinaison dudit matériau de nanocellulose, ou d'un dérivé de celui-ci, avec un ou plusieurs autres matériaux, de préférence avec un polymère sélectionné parmi les polyoléfines, les polyesters, les polyuréthanes, les polyamides, ou des combinaisons de ceux-ci, ou avec du carbone pour former un composite.
 
15. Procédé selon la revendication 1, dans lequel ledit produit contenant de la nanocellulose est configuré électrochimiquement pour transporter ou stocker un courant ou une tension électrique, est incorporé dans un filtre, une membrane, ou un autre dispositif de séparation, est incorporé comme additif dans un revêtement, une peinture, ou un adhésif, est configuré comme un catalyseur, un substrat de catalyseur, ou un co-catalyseur, est incorporé comme un additif de ciment, est un revêtement de papier, est incorporé comme un agent épaississant ou un modificateur de rhéologie, ou est incorporé comme un additif dans un fluide de forage, de préférence dans un fluide de récupération d'huile et/ou un fluide de récupération de gaz.
 




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Cited references

REFERENCES CITED IN THE DESCRIPTION



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Patent documents cited in the description




Non-patent literature cited in the description