High shear drying and concentrating methods and systems

Abstract

Substances that are suspended, dispersed, and / or dissolved in a liquid can be dried or concentrated to obtain dried or concentrated material. For example, cellulose nanofibrils (CNFs) are cellulose-based materials with nanoscale dimensions and desirable properties formed by treating macroscopic cellulose fibers to defibrillate them into a slurry or feedstock, followed by drying of the feedstock to form dry CNF material. Drying methods such as spray drying and oven drying cause excessive aggregation of the dried materials, while freeze drying and supercritical CO2 drying are costly and difficult to scale up. The present embodiments include methods and systems using high shear for drying or concentrating liquid feedstocks containing suspended and / or dissolved substances to produce dried or concentrated substances in a scalable manner with high yield.

Description

HIGH SHEAR DRYING AND CONCENTRATING METHODS AND SYSTEMSCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to and the benefit of U.S. Provisional Application No. 63 / 551,895 filed February 09, 2024, the contents of which are incorporated by reference in its entirety.BACKGROUND

[0002] Substances that are suspended and / or dissolved in a liquid can be dried or concentrated using a variety of methods and systems to produce products (e.g., dried materials, concentrated substances, etc.) of different structures, depending on the drying or concentrating procedures. For example, cellulose nanofibrils (CNFs) are a form of cellulose- based nanomaterials, among others such as cellulose nanocrystals and bacterial nanocellulose, and are typically produced via mechanical refining of lignocellulosic materials in a liquid feedstock. CNFs have a hierarchical structure ranging from the micron scale down to nanometer dimensions with desirable characteristics including biodegradability, low density, high surface area, high aspect ratio and superior mechanical properties. Potential fields of application of CNFs include biomedical and health care, electronics and sensors, construction, food and packaging, consumer products, and as a reinforcing agent in thermoplastic feedstocks for large scale additive manufacturing. Examples of substances that are suspended and / or dissolved in liquid and can be dried or concentrated to form products include proteins, nucleic acids, polysaccharides, milk, viruses, black liquor, lignin, maple sap, salts, and pharmaceuticals.SUMMARY

[0003] Described herein are systems and methods for the high shear drying of suspended materials and / or dissolved solutes in liquid solvents, which may include the generation of turbulent airflows that apply high shear forces, for example, via one or more vortices.

[0004] In one aspect, the present embodiments are directed to a method for producing dried cellulose nanofibril (CNF) material, including: providing a cellulosic feedstock; heating the cellulosic feedstock; exposing the cellulosic feedstock to a high shear environment to form treated material; and collecting the treated material, wherein the treated material includes a plurality of cellulose nanofibrils, and wherein the cellulose nanofibrils are substantially not aggregated.

[0005] In some embodiments, the high shear environment includes a heated, turbulent air flow or gas flow. In some embodiments, the heating and exposing happen substantially simultaneously. In some embodiments, the method additionally includes filtering the treated material to form filtered material. In some embodiments, filtering includes passing at least a portion of the treated material through meshes, filter papers, or combinations thereof. In some embodiments, the cellulosic feedstock includes at least 50% fines (e.g., at least 60% fines, 70% fines, 80% fines, 85% fines, 90% fines, 95% fines, 99% fines, 100% fines).

[0006] In some embodiments, heating the feedstock is to about 95 °C (e.g., about room temperature, about 80 °C, about 85 °C, about 90 °C). In some embodiments, heating the feedstock is to about the boiling point of the feedstock. In some embodiments, the heated, turbulent airflow is heated to about 375 °C (e.g., about 250 °C, about 275 °C, about 300 °C, about 325 °C, about 350 °C, about 400 °C, about 425 °C, about 450 °C). In some embodiments, at least 20 wt% of the cellulosic feedstock becomes cellulose nanofibrils by end of the method (e.g., at least 30 wt%, 40 wt%, 50 wt%, 60 wt%, 70 wt%, 80 wt%, 90 wt%).

[0007] In some embodiments, the cellulosic feedstock includes an aqueous suspension of cellulose or lignocellulose. In some embodiments, the aqueous suspension includes at least 0.01 wt% cellulose (e.g., at least 0.1 wt%, at least 1 wt%, at least 2 wt%, at least 3 wt%, at least 4 wt%, at least 5 wt%). In some embodiments, the cellulosic feedstock is fed into the high shear environment at a rate of about 10 ml / min (e.g., about 20 ml / min, about 50 ml / min, about 100 ml / min, about 1 L / min, about 10 L / min, about 100 L / min, about 500 L / min).

[0008] In some embodiments, the heated, turbulent airflow includes one or more vortices. In some embodiments, the one or more vortices are formed by at least one of aVenturi plate, a nozzle, or a plenum chamber with a plurality of perforations. In some embodiments, the heated, turbulent airflow comprises a first vortex and a second vortex, wherein the first vortex and the second vortex rotate about a common axis.

[0009] In some embodiments, the plurality of cellulose nanofibrils include an average diameter below about 200 nm. In some embodiments, the heated, turbulent airflow includes a flow rate of 40 to 200 scf / h.

[0010] In some embodiments, providing the cellulosic feedstock includes loading the cellulosic feedstock into at least one feed reservoir, and using at least one pump module (e.g., a syringe pump, a gear pump, a diaphragm pump, a centrifugal pump) to transport the cellulosic feedstock out of the at least one reservoir. In some embodiments, collecting comprises removing and gathering dried CNF material after exposure the high shear environment.

[0011] In another aspect, the present embodiments are directed to a system for drying or concentrating a liquid feedstock including at least one liquid solvent and a quantity of dispersed materials and / or dissolved solutes, including: an input module for receiving the liquid feedstock; a turbulence module functionally connected to the input module; a collection module functionally connected to the turbulence module; a first heat source functionally connected to an outflow of the input module; and a second heat source functionally connected to a pressurized input gas flow into the turbulence module.

[0012] In some embodiments, the turbulence module is functionally connected to a source of heated, pressurized gas. In some embodiments, the input module includes: at least one feed reservoir fluidly connected to a pump module (e.g., syringe pump). In some embodiments, the input module further includes: at least one pressurized gas source (e.g., compressed gas cylinder, ambient air with compressor); and a plurality of valves to control flow of gas between the at least one feed reservoir and pump, and the at least one pressurized gas source. In some embodiments, the turbulence module includes a nozzle. In some embodiments, the turbulence module further includes a venturi plate. In some embodiments, the system further includes a vacuum system (e.g., a regenerative blower, or a vacuum pump) functionally connected downstream of the collection module.

[0013] In some embodiments, the collection module includes one or more (e.g., two or more) filter papers and one or more (e.g., two or more, three or more, four or more) meshes, wherein the one or more filter papers and the one or more meshes are stacked together. In some embodiments, the one or more filter papers comprise a first filter paper, and a second filter paper. In some embodiments, the one or more meshes includes four meshes comprising mesh sizes of 100, 200, 400, and 1000.

[0014] In some embodiments, first heat source includes a heat exchanger. In some embodiments, the second heat source includes a heat exchanger.

[0015] In some embodiments, the collection module includes a reservoir to collect concentrated substances.

[0016] In some embodiments, the turbulence module includes: an injector nozzle; a plenum chamber including a first cylinder disposed coaxially around the fuel injector nozzle, the first cylinder including a plurality of radial holes (e.g., slots, angled holes, nozzles, tapered holes), and a second cylinder disposed coaxially around the first cylinder, wherein a first stream of heated, pressurized gas flow flows through the fuel injector nozzle to generate a first vortex, and wherein a second stream of heated, pressurized gas flow flows through a space between the first cylinder and the second cylinder and through the plurality of radial holes to generate a second vortex.

[0017] In some embodiments, the second vortex is located within an internal diameter of the first cylinder. In some embodiments, the input module includes feed reservoirs that can be refilled or swapped for continuous operation of the system. In some embodiments, the turbulence module further includes at least one of a cooling module, a flushing and / or cleaning module, or a mechanism for switching between nozzles. In some embodiments, the collection module further includes at least one of a bag house, an electrostatic precipitator, or a centrifugal collection system.

[0018] In another aspect, the present embodiments are directed to a composite material including: a polymer matrix; and a plurality of cellulose nanofibrils (CNFs) distributed throughout the polymer matrix, wherein the cellulose nanofibrils are produced by a high shear drying method. In some embodiments, the polymer matrix comprises polylactic acid (PLA). In some embodiments, the polymer matrix includes at least one of athermoplastic polymer, polyethylene, polypropylene, or nylon. In some embodiments, the CNFs are distributed throughout the polymer matrix by melt mixing dry CNF material with pellets of the polymer matrix. In some embodiments, the CNFs comprise a plurality of nanofibrils with diameters below about 200 nm.

[0019] In another aspect, the present embodiments are directed to a method for forming a composite material, including: obtaining a quantity of cellulose nanofibril (CNF) material; obtaining a quantity of polymer pellets; drying the CNF material and polymer pellets at a drying temperature (e.g., 60°C) for a drying duration (e.g., 12 hours) in an oven; loading the polymer pellets into a shear mixer; operating the shear mixer (e.g., at 175°C and 70 rpm for 3 minutes) containing the polymer pellets; loading the CNF material into the shear mixer; operating the shear mixer (e.g., at 175°C and 70 rpm for 3 minutes) containing the polymer pellets and the CNF material; and removing a product from the shear mixer, the product comprising the composite material of the polymer and the CNF material.

[0020] In some embodiments, the CNF material is obtained by a high shear drying method. In some embodiments, the polymer pellets comprise polylactic acid (PLA). In some embodiments, the polymer pellets include at least one of a thermoplastic polymer, polyethylene, polypropylene, or nylon. In some embodiments, the CNF material includes a plurality of nanofibrils with average diameters below about 200 nm.

[0021] In another aspect, the present embodiments are directed to a method for drying or concentrating a liquid feedstock, including: providing a liquid feedstock; heating the liquid feedstock; exposing the liquid feedstock to a high shear environment to form treated material; and collecting the treated material.

[0022] In some embodiments, the liquid feedstock includes one or more liquid solvents and a plurality of suspended materials and / or dissolved substances. In some embodiments, the suspended materials and / or dissolved substances comprise at least one of cellulosic materials, polysaccharides, viruses, nucleic acids, proteins, milk, salts, black liquor, lignin, maple sap, or pharmaceuticals.

[0023] In some embodiments, the high shear environment includes a heated, turbulent air flow. In some embodiments, the heating and exposing happen substantially simultaneously. In some embodiments, the method additionally includes filtering the treatedmaterial to form filtered material. In some embodiments, filtering includes passing at least a portion of the treated material through meshes, filter papers, or combinations thereof.

[0024] In some embodiments, heating the feedstock is to about or above the boiling point of the feedstock (e.g., within 5 degrees Celsius of the boiling point, within 10 degrees Celsius of the boiling point, within 15 degrees Celsius of the boiling point). In some embodiments, the heated, turbulent airflow is heated to about 375 °C (e.g., about 250 °C, about 275 °C, about 300 °C, about 325 °C, about 350 °C, about 400 °C, about 425 °C, about 450 °C). In some embodiments, the liquid feedstock is fed into the high shear environment at a rate of about 10 ml / min (e.g., about 20 ml / min, about 30 ml / min, about 50 ml / min, about 100 ml / min).

[0025] In some embodiments, the heated, turbulent airflow includes one or more vortices. In some embodiments, the one or more vortices are formed by at least one of a Venturi plate, a nozzle, or a plenum chamber with a plurality of holes. In some embodiments, the heated, turbulent airflow comprises a first vortex and a second vortex, wherein the first vortex and the second vortex rotate about a common axis in opposite directions. In some embodiments, the heated, turbulent airflow comprises a first vortex and a second vortex, wherein the first vortex and the second vortex rotate about a common axis in the same direction. In some embodiments, the heated, turbulent airflow includes a flow rate of 40 to 200 scf / h.

[0026] In some embodiments, providing the liquid feedstock includes loading the liquid feedstock into at least one feed reservoir, and using at least one pump module (e.g., a syringe pump, a gear pump, a diaphragm pump, a centrifugal pump) to transport the liquid feedstock out of the at least one reservoir. In some embodiments, collecting includes removing and gathering dried material or concentrated substances from the high shear environment.BRIEF DESCRIPTION OF THE DRAWING

[0027] The present teachings described herein will be more fully understood from the following description of various illustrative embodiments, when read together with the accompanying figures. It should be understood that the figures described below are forillustration purposes only and are not intended to limit the scope of the present teachings in any way.

[0028] FIG. 1 shows schematic diagrams of the structures of glucose, cellobiose, and cellulose.

[0029] FIG. 2 shows a schematic diagram of the acid hydrolysis of cellulose microfibrils to release cellulose nanocrystals (CNC).

[0030] FIG. 3 shows atomic force microscopy (AFM) images of CNFs from 50% fines to 100% fines, illustrating hierarchical structure.

[0031] FIG. 4A shows scanning electron microscopy (SEM) images of oven-dried CNFs.

[0032] FIG. 4B shows SEM images of freeze-dried CNFs.

[0033] FIG. 4C shows SEM images of spray-dried CNFs.

[0034] FIG. 4D shows SEM images of supercritical CO2 dried CNFs.

[0035] FIG. 5 shows a process flow diagram of a high shear drying system, according to aspects of the present embodiments.

[0036] FIG. 6 shows a photograph of a high shear drying system, according to aspects of the present embodiments.

[0037] FIG. 7 shows a schematic diagram of a turbulence agent nozzle, according to aspects of the present embodiments.

[0038] FIG. 8 shows a schematic diagram of another embodiment of a turbulence agent nozzle, according to aspects of the present embodiments.

[0039] FIG. 9 shows a side view computer-aided design (CAD) diagram of a turbulence agent nozzle, according to aspects of the present embodiments.

[0040] FIG. 10 shows another side view CAD diagram of a turbulence agent nozzle, according to aspects of the present embodiments.

[0041] FIG. 11 shows an exploded side view CAD diagram of the components of a turbulence agent nozzle, according to aspects of the present embodiments.

[0042] FIG. 12 shows an exploded perspective view CAD diagram of the components of a turbulence agent nozzle, according to aspects of the present embodiments.

[0043] FIG. 13 shows a cross-sectional side view CAD diagram of the components of an assembled turbulence agent nozzle, according to aspects of the present embodiments.

[0044] FIG. 14A shows a photograph of an assembled turbulence agent nozzle with inner nozzle, inner cylinder, and outer cylinder visible, according to aspects of the present embodiments.

[0045] FIG. 14B shows a photograph of the inner cylinder (i.e., inner wall of the plenum chamber with radial circumferential holes visible, which help generate a secondary vortex, according to aspects of the present embodiments.

[0046] FIG. 14C shows a photograph of an assembled turbulence module 141, with injection nozzle 512 and plenum chamber formed by the inner cylinder 516 and outer cylinder 518 visible, and with the primary vortex and secondary vortex indicated by the small and large curved arrows, respectively, according to aspects of the present embodiments

[0047] FIG. 15 shows an SEM image of CNFs from high shear drying showing nanofibrils, according to aspects of the present embodiments.

[0048] FIG. 16 shows an SEM image of CNFs from high shear drying showing nanofibrils, according to aspects of the present embodiments.

[0049] FIG. 17 shows an SEM image of CNFs from high shear drying showing nanofibrils, according to aspects of the present embodiments.

[0050] FIG. 18 shows an SEM image of CNFs from high shear drying showing nanofibrils and globular features, according to aspects of the present embodiments.

[0051] FIGS. 19A, 19B, 19C, and 19D show histograms of fibril diameters from SEM images of CNFs from high shear drying, according to aspects of the present embodiments.

[0052] FIG. 20A shows a photograph of neat polylactic acid (PLA), according to aspects of the present embodiments.

[0053] FIG. 20B shows a photograph of PLA compounded with CNFs from high shear drying, according to aspects of the present embodiments.

[0054] FIG. 21 shows a photograph of tensile bars of neat PLA in dogbone Type V shapes for ASTM D638 tensile testing, according to aspects of the present embodiments.

[0055] FIGS. 22A, 22B, 22C, and 22D show photographs of tensile bars of PLA compounded with, respectively, 5 wt%, 10 wt%, 20 wt%, and 30 wt% CNFs from high shear drying in dogbone Type V shapes for ASTM D638 tensile testing, according to aspects of the present embodiments.

[0056] FIGS. 23 A, 23B, 23C, and 23D show photographs of tensile bars of PLA compounded with, respectively, 5 wt%, 10 wt%, 20 wt%, and 30 wt% CNFs from spray drying in dogbone Type V shapes for ASTM D638 tensile testing, according to aspects of the present embodiments.

[0057] FIGS. 24A and 24B show plots of ultimate tensile strength (UTS) for PLA compounded with varying concentrations of CNFs from spray drying (SD) and high shear drying (HSD), according to aspects of the present embodiments.

[0058] FIGS. 25A and 25B show plots of tensile modulus for PLA compounded with varying concentrations of CNFs from spray drying (SD) and high shear drying (HSD), according to aspects of the present embodiments.

[0059] FIG. 26 shows a flow chart diagram for a method of high shear drying to form dried materials, according to aspects of the present embodiments.

[0060] FIG. 27 shows a flow chart diagram for a method of high shear drying to form dried materials, according to aspects of the present embodiments.

[0061] FIG. 28 shows a flow chart diagram for a method for forming a composite material that includes CNFs, according to aspects of the present embodiments.DEFINITIONS

[0062] About, Approximately: As used herein, the terms “about” and “approximately” as used in reference to a value, refers to a value that is similar, in context to the referenced value. In general, those skilled in the art, familiar with the context, will appreciate the relevant degree of variance encompassed by “about” and “approximately” in that context. For example, in some embodiments, the terms “about” and “approximately”may encompass a range of values that within 25%, 20%, 19%, 18%, 17%, 16%, 15%, 14%, 13%, 12%, 11%, 10%, 9%, 8%, 7%, 6%, 5%, 4%, 3%, 2%, 1%, or less of the referred value.

[0063] Associated with: As used herein, the term, “associated with” refers to two events or entities when presence, level and / or form of one is correlated with that of the other. In some embodiments, two or more entities are physically “associated” with one another if they interact, directly or indirectly, so that they are and / or remain in physical proximity with one another. In some embodiments, two or more events may be correlated with each other by proximity in time and / or causation by each other and / or by other unrelated entities and / or events. In some embodiments, one or more events and one or more entities may be correlated with each other by some physical and / or temporal relationships between them.

[0064] Cellulose nanofibril (CNF): As used herein, cellulose nanofibrils (CNFs) are structures composed of cellulose formed into fibrils with high aspect ratio and nanometerscale lateral dimensions (e.g., diameters below 200 nm, diameters below 100 nm, diameters between 200 nm and 15 micrometers). In some embodiments, a population or a sample of CNFs may include CNFs with a distribution of sizes, with diameters ranging from below 100 nm up to 15 micrometers.

[0065] Cellulosic slurry or cellulosic feedstock: As used herein, a cellulosic slurry or cellulosic feedstock, or just slurry or feedstock, refer to a cellulose-containing liquid slurry that is produced from various mechanical, chemical, and / or biological defibrillation methods on cellulosic precursor materials (e.g., lignocellulose from plants, or other structures and / or sources), so that cellulosic fibers and structures of a variety of sizes and dimensions are in suspension. In some embodiments, a cellulosic slurry or feedstock is then dried to remove the liquid medium to produce dried cellulosic structures or materials or powders.

[0066] CNF material: As used herein, a CNF material is generated by drying of CNF feedstock or CNF slurry to remove liquid media to produce a dried product that may include powders, solids, blocks, films, fibers, particles, and / or crystals. In some embodiments, a CNF material may contain cellulosic structures that are nanoscaled, micron-scaled, or larger.

[0067] Injection nozzle: As used herein, an injection nozzle is a nozzle structure that may be used to produce a liquid / gas mixture to be sprayed (e.g., a fuel / air mixture in the case of an injection nozzle used as a fuel injection nozzle in a furnace or an internal combustion engine). In some embodiments, an injection nozzle is used to expose a liquidfeedstock to a high shear environment to dry the liquid component (e.g., one or more solvents) of the liquid feedstock. In some embodiments, an injection nozzle breaks up fluid entering from a center port using high shear using compressed air in a tornado-like vortex.

[0068] High Shear: As used herein, high shear refers to high shear forces that are generated in a turbulent airflow condition such as a vortex, or by the use of mechanical agitation or blades.

[0069] Liquid feedstock: As used herein, liquid feedstock refers to a liquid (e.g., one or more solvents) in which is dispersed or suspended a material, and / or dissolved a solute, or a combination of materials and solutes. Liquid feedstock is fed into a high shear drying and / or concentrating system to dry the dispersed or suspended materials to form dried materials, or to concentrate the liquid feedstock to achieve a product that has a concentrated amount of the dissolved and / or suspended substance. The dispersed, suspended, and / or dissolved substances may include cellulosic materials, nanoparticles, biomolecules, polysaccharides, polymers, viruses, milk, nucleic acid, black liquor, lignin, pharmaceuticals, etc.

[0070] Percent fines: As used herein, percent fines refers to the percentage by number of particles of material in a sample that is less than 200 micrometers in size (e.g., not detected optically by a morphological analyzer).

[0071] Plenum chamber: As used herein, a plenum chamber is a pressurized housing containing a fluid (e.g., air, gas) at a positive pressure. In some embodiments, a plenum chamber may be a confined volume into which pressurized air may be injected, and when expelled may be used to generate a vortex.

[0072] Regenerative blower: As used herein, a regenerative blower is a device that can move gas (e.g., generate suction or blow gas). In some embodiments, a regenerative blower may include an impeller that rotates rapidly to pull air in through an inlet side, accelerate the air, and push air out through an outlet side. In some embodiments, an impeller in a regenerative blower may include multiple blades similar to a turbine. In some embodiments, regenerative blowers are used to provide movement of gases for pneumatic conveying and other applications. In some embodiments, a regenerative blower is used to pull hot air with entrained CNFs through a drying and / or concentrating system and through a collection or filtration module.

[0073] Venturi plate: As used herein, a venturi plate, related to an orifice plate, is a structure with an entrance opening which narrows to a constriction, and then expands to an exit hole. A venturi plate operates based on the Venturi effect, which is a reduction in fluid pressure for a flow that passes through a constriction in a pipe or other passage. In some embodiments, a venturi plate may be incorporated into a turbulence module to increase turbulence to an airflow.DETAILED DESCRIPTION OF CERTAIN EMBODIMENTS

[0074] It is contemplated that methods, systems, compositions, and processes described herein encompass variations and adaptations developed using information from the embodiments described herein. Adaptation and / or modification of the methods, systems, compositions, and processes described herein may be performed, as contemplated by this description.

[0075] Throughout the description, where methods, systems, compositions, and / or processes are described as having, including, or comprising specific components, or where processes and methods are described as having, including, or comprising specific steps, it is contemplated that, additionally, there are embodiments of the systems and / or compositions that consist essentially of, or consist of, the recited components, and that there are embodiments of the processes and methods that consist essentially of, or consist of, the recited steps.

[0076] It should be understood that the order of steps or order for performing certain action is immaterial so long as the method and / or processes remain operable. Moreover, two or more steps or actions may be conducted simultaneously.

[0077] The mention herein of any publication, for example, in the Background section, is not an admission that the publication serves as prior art with respect to any of the claims presented herein. The Background section is presented for purposes of clarity and is not meant as a description of prior art with respect to any claim.

[0078] Headers are provided for the convenience of the reader; the presence and / or placement of a header is not intended to limit the scope of the subject matter described herein.

[0079] Provided herein are improved technologies (e.g., methods and systems) for the drying and / or concentrating of liquid feedstock (e.g., cellulosic feedstock, biomolecularfeedstock) to form materials (e.g., cellulose nanofibrils (CNFs)) in a solid form and / or to form liquids of concentrated substances. In some embodiments, dried materials (e.g., cellulosic materials, CNFs, biomolecular materials, etc.) may include structures with nanometer-scale dimensions and minimal aggregation. In some embodiments, methods and systems are scalable.

[0080] Cellulose is a simple homopolysaccharide that consists of linear chains of D- glucose dimers, termed cellobiose, which commonly number between 10,000 and 15,000 units. The cellulose polymer chains can be stacked either parallel or antiparallel with stabilization occurring via intermolecular hydrogen bonding due to the high density of free hydroxyl groups. The structure of cellulose contains both crystalline regions with highly ordered and tightly packed fibrils, and amorphous regions with less ordered and loosely packed fibrils. Native cellulose may be broken down into its constituent microfibrils using mechanical, chemical, or biological methods, and are the basic building block of cellulose. Drying of cellulose is very challenging due to aggregation driven by hydrogen bonding, and low degradation temperatures of cellulose. FIG. 1 are schematic diagrams of the structures of glucose, cellobiose, and cellulose (Lunardi, V. B., Soetaredjo, F. E., Putro, J. N, Santoso, S. P, Yuliana, M., Sunarso, J., Ju, Y. & Ismadji, S. (2021). Nanocelluloses: Sources, Pretreatment, Isolations, Modification, and Its Application as the Drug Carriers. Polymers, 13, 2052.).

[0081] Nanocellulose (NC) is a term used to describe cellulosic materials in which at least one of the fiber dimensions is on the nanoscale. Nanocellulose typically has a diameter of less than 100 nm, while its length may approach several microns. The extraction and processing methods used to form NC dictates the form of the NC obtained and affects many of the resultant physical properties such as surface area, strength, and stiffness. There are three basic types of nanocellulose; bacterial nanocellulose (BNC), cellulose nanocrystals (CNC) and cellulose nanofibrils (CNFs), each of which are produced via unique processes. Bacterial nanocellulose is composed of ultrafine fibers that are highly crystalline with diameters ranging from 20 to 100 nm and lengths of several micrometers. Cellulose nanocrystals (CNC) are short, rod-shaped particles with diameters of 10 to 30 nm, and lengths of 100 to 200 nm. CNFs are typically longer, more flexible and are often branched, with fiber diameters from 10 nm to 10 pm and lengths of up to several micrometers. CNFs are produced by defibrillation of native macroscopic cellulose fibers, and typically contain aportion of micron scale fibers which branch into smaller and smaller fibers / fibrils, eventually reaching the nanometer scale. The relative amounts of micro and nano fibrils depends on the processing method.

[0082] FIG. 3 shows atomic force microscopy (AFM) images of CNFs from 50% fines to 100% fines, illustrating a hierarchical structure (Kelly, P. V, Gardner, D. J., & Gramlich, W. M. (2021). Optimizing lignocellulosic nanofibril dimensions and morphology by mechanical refining for enhanced adhesion. Carbohydrate Polymers, Vol. 273, 118566.). The term ‘percent fines’ refers to the percentage by number of particles of material in a sample that is less than 200 micrometers in size (and thus not detected optically by a morphological analyzer). At low percent fines (correlating to minimal defibrillation), the sample comprises mostly fibers with diameters on the micrometer scale. As the extent of defibrillation increases, the percentage of fines increases and the large fibers are observed to become less common, with an increasing amount of fiber branching into progressively smaller fibrils.

[0083] Prior to the present disclosure, production of cellulose nanofibrils (CNF) usually consisted of biological, chemical, or mechanical defibrillation, or a combination of these methods. Mechanical defibrillation is the most commonly used and may be applied via high-pressure homogenization, microfluidization, or microgrinding. Mechanical degradation / defibrillation begins with large cellulose fibers (about tens of microns in diameter) that are mechanically reduced to the nanoscale by the application of high shear forces. A liquid medium, most commonly water, is used for the defibrillation process to produce a slurry. To decrease the energy required for mechanical disintegration, chemical and enzymatic pretreatment may be used, such as the use of alkali to dissolves the lignin structure between the fibers and the use of enzymes such as xylanases and laccases to eliminate the remaining lignin and hemicellulose content. FIG. 2 is a schematic diagram of acid hydrolysis of cellulose microfibrils to release cellulose nanocrystals (CNC) (Mishra R. K., Sabu A., & Tiwari, S. K. (2018). Materials chemistry and the futurist eco-friendly applications of nanocellulose: status and prospect. Journal of Saudi Chemical Society 22:949- 978.).

[0084] In accordance with various aspects of the disclosure, production of CNFs typically involves first forming a cellulosic feedstock as described above. The feedstock, usually an aqueous solution, includes a heterogeneous mixture of cellulosic structures ofdifferent dimensions, ranging from the nanometer scale to micron scale, in a slurry. The feedstock must then be dried to remove the solvent while preserving as much of the nanofibrils as possible, resulting in a dry CNF material. One of the main challenges in employing CNFs is the ability to dry the feedstock without cellulosic structures undergoing hydrogen-bond-driven aggregation, and concomitant loss of its nanoscale structure. Conventional methods of drying such as oven drying and spray drying result in micron size and larger monoliths. FIG. 4A shows scanning electron microscopy (SEM) images of oven- dried CNFs, showing aggregation and loss of nanoscale elements (Sinquefield, S., Ciesielski, P. N., Li, K., Gardner, D. J. & Ozcan, S. (2020). Nanocellulose Dewatering and Drying: Current State and Future Perspectives. ACS Sustainable Chem. Eng. 8, 26, 9601-9615.). FIG. 4C are SEM images of spray-dried CNFs, showing globular aggregations and loss of nanoscale elements (Sinquefield et al., 2020).

[0085] Freeze drying and supercritical CO2 drying have been shown to largely preserve the nanostructures of CNFs, but these methods are expensive, slow, use a lot of energy, and difficult to scale up. FIG. 4B are SEM images of freeze-dried CNFs (Sinquefield et al. 2020), and FIG. 4D are SEM images of supercritical CO2 dried CNFs (Peng, Y, Gardner, D. J., & Han, Y. (2011). Drying cellulose nanofibrils: in search of a suitable method. Cellulose, 19, 91-102) showing nanostructured CNFs.

[0086] CNFs may have applications as reinforcement in composite materials. Previous research has indicated that the incorporation of CNF as a reinforcing filler in polylactic acid (PLA) results in improved mechanical properties, but increases in properties such as tensile strength and tensile modulus depend on the means of composite production, surface modification of CNF, and perhaps most significantly, the method used to dry the CNF materials prior to composite formation. Spray dried CNFs, which have more aggregation, do not enhance mechanical properties (Kelly et al., 2023), while freeze dried CNF that have much better preservation of nanofibrillar structure, result in increasing tensile strength and tensile modulus (Tekinalp et al., 2019).

[0087] The present disclosure provides, inter alia, methods to thermally dry cellulosic feedstock without the structures undergoing significant aggregation or degradation to form nanostructured CNFs, while being scalable, cost-effective, and energy efficient. In accordance with various aspects, the present disclosure features new methods and systemsfor drying and / or concentrating CNFs using high shear forces and heating that result in CNF materials with a significant yield of nanofibrillar structure.High Shear Drying and / or Concentrating Methods

[0088] The present disclosure describes high shear drying and / or concentrating methods that apply high shear forces and optionally thermal energy to liquid feedstocks (e.g., cellulosic feedstocks, biomolecule feedstocks, liquid solutions, etc.) to produce dried and / or concentrated materials (e.g., CNFs with increased nanofibrous yield). In some embodiments, provided methods use heated, pressurized air that is injected into specialized nozzle systems to generate one or more (e.g., two or more, three or more, four or more, etc.) vortices of varying (e.g., opposite, same) directions into which flows of heated liquid feedstock is introduced, thus applying high shear and high temperature to the liquid feedstock and producing dried materials and / or concentrated solutes that may be entrained in air or gas flow and which can then be collected (e.g., via filtration).Steps in High Shear Drying and / or Concentrating Methods

[0089] In some embodiments, liquid feedstocks (e.g., cellulosic feedstocks, biomolecule feedstocks, suspensions, dispersions, solutions, etc.) are provided as starting materials and subjected to high shear drying and / or concentrating methods to produce dried and / or concentrated materials (e.g., CNF materials). Liquid feedstocks can include any application-appropriate initial concentration of suspended material and / or dissolved solutes (e.g., cellulosic suspended material) and / or any application-appropriate size distribution of particles of suspended materials (e.g., cellulosic fibers). For example, in some embodiments, cellulosic material may contain different initial concentrations of cellulosic material (e.g., approximately 1 wt%, approximately 2 wt%, approximately 3 wt%, approximately 3.5 wt%, approximately 4 wt%, etc.) which may include different size distributions of particles of cellulosic fibers (e.g., at least 80 percent fines, at least 85 percent fines, at least 90 percent fines, at least 95 percent fines, approximately 100 percent fines, etc.). In accordance with various embodiments, cellulosic feedstocks may be dispersed in liquid media (e.g., aqueous media, solvent media, etc.). Cellulosic feedstocks may be produced from any of a variety of different sources (e.g., plant sources, bacterial sources, etc.). By way of non-limitingexample, plant sources of cellulosic feedstocks may include, but are not limited to, Northern softwood bleached kraft pulp or flax or other sources or combinations of sources (e.g., softwoods, hardwoods, corrugated cardboard, paper, hemp, seaweed, agricultural waste, municipal waste, etc.). Introduction of liquid feedstock may include adding a quantity of liquid feedstock into an input of a high shear drying and / or concentrating system.

[0090] In some embodiments, examples of liquid feedstocks may include dispersions or solutions of proteins, nucleic acids, polysaccharides, milk, viruses, black liquor, lignin, maple sap, salts, and pharmaceuticals.

[0091] In accordance with various embodiments, a liquid feedstock (e.g., cellulosic feedstock) is heated to any of a variety of temperatures above room temperature, for example, prior to exposure to turbulent airflow. In some embodiments, a liquid feedstock is heated to about 95 °C (e.g., about 75 °C, about 80 °C, about 85 °C, about 90 °C, below about 100 °C). In some embodiments, a liquid feedstock is heated so that it is at an elevated temperature (i.e., above room temperature) before entering a heated, turbulent airflow for high shear drying. In some embodiments, a liquid feedstock is heated to the boiling point of the liquid feedstock, or to a temperature above the atmospheric boiling point of the liquid feedstock for a pressurized liquid feedstock. In some embodiments, a liquid feedstock may be heated by passing the feedstock through a tube or hose whose exterior is heated by a heater (e.g., a block heater or heat exchanger). Generally, liquid feedstock is heated to just below the boiling point of the solvent (e.g., water) of the feedstock, so that thermal energy is provided to the feedstock without forming any gaseous or vapor components. In some embodiments, the feedstock is not heated (i.e., maintained at ambient temperature). In some embodiments, the liquid feedstock is heated to within 5 degrees Celsius of the boiling point (e.g., within 10 degrees Celsius of the boiling point, within 15 degrees Celsius of the boiling point).

[0092] In some embodiments, a liquid feedstock is exposed to a high shear environment (e.g., a heated, turbulent airflow) (e.g., substantially simultaneously). In accordance with various embodiments, a rate of feeding of the liquid feedstock into high shear environment may be at about 10 ml / min (e.g., about 20 ml / min, about 30 ml / min) by use of a pump or mechanical conveyance (e.g., a syringe pump). The increased pressure may be between 40 and 200 psi (e.g., between 20 and 100 psi, between 50 and 200 psi, between 50 and 100 psi, between 75 and 200 psi, between 40 and 300 psi, between 20 and 300 psi,above 200 psi, above 500 psi, above 1000 psi). In some embodiments, a high shear environment includes mechanical means for generating shear (e.g., blades, impellers, stators).

[0093] In some embodiments, heating and exposing happen substantially simultaneously. In some embodiments, a liquid feedstock is first heated while it is flowing, and then the flow of feedstock enters a region of heated, turbulent airflow. In general, a turbulent airflow includes a flow of air (e.g., compressed air, compressed gases) that has turbulent and non-laminar flow, with chaotic changes in pressure, flow velocity, and / or flow direction. In some embodiments, air or gas that is used to form the turbulent airflow is first heated before turbulence is generated.

[0094] In some embodiments, a turbulent airflow may include a vortex (e.g., one or more vortices). In some embodiments, a turbulent airflow may include two or more vortices, which may each be oriented in a different direction (e.g., two vortices rotating and / or oriented in opposite directions). In some embodiments, a liquid feedstock (e.g., cellulosic feedstock, biomolecule feedstock) is exposed to a first vortex of heated air, and then is exposed to a second vortex of heated air operating in a different direction than the first vortex. In some embodiments, a heated, turbulent airflow is heated to at least about 375 °C (e.g., at least about 250 °C, at least about 275 °C, at least about 300 °C, at least about 325 °C, at least about 350 °C, at least about 400 °C, at least about 425 °C, at least about 450 °C). In some embodiments, the heated, turbulent airflow includes a flow rate of 40 to 200 scf / h (e.g., 20 to 200 scf / h, e.g., 10 to 100 scf / h, e.g., 10 to 200 sc / f, e.g., 40 to 100 scf / h, e.g., 40 to 300 scf / h, e.g., 20 to 400 scf / h, e.g, above 400 scf / h, above 600 scf / h, above 1000 scf / h).

[0095] Without being bound to any particular theory, turbulent airflow may generate high shear forces that may pull apart, and / or keep apart, cellulose nanofibrils within the cellulosic feedstock, and may contribute to evaporation of water (e.g., solvent) from the cellulosic feedstock. Without being bound to any further particular theory, the heat from the heated cellulosic feedstock and from the heated, turbulent airflow may also contribute to evaporation of water (e.g., solvent) from the cellulosic feedstock.

[0096] As a result of exposure to a combination of thermal energy (e.g., heat used to heat liquid feedstock (e.g., cellulosic feedstock), heat embodied in the heated air employed to generate turbulent airflow) and high shear (e.g., forces generated within turbulent airflow or within vortex) materials are dried from a liquid feedstock to form a solid-phase materialand / or concentrated solution (e.g., powders, solids, blocks, films, fibers, particles, and / or crystals).

[0097] In some embodiments, a cellulosic feedstock that has been dried forms CNF material in which there are cellulosic structures that are nanoscaled, micron-scaled, or larger. In some embodiments, dried CNF material contains CNFs that are substantially not aggregated. In some embodiments, dried CNF material is in a substantially powder form. In some embodiments, treated material from a cellulosic feedstock is substantially CNF material with at least 40 wt% of the cellulosic feedstock becoming cellulose nanofibrils after high shear drying and / or concentrating methods (e.g., at least 50 wt%, 60 wt%, 70 wt%, 80 wt%, 90 wt%), of which the plurality of CNFs have an average diameter below about 200 nm (e.g., below about 500 nm, below about 400 nm, below about 300 nm, below about 100 nm).

[0098] In some embodiments, treated materials are collected, which may include removing and gathering dried material from the heated, turbulent airflow. Collecting treated material may include locating deposits of material on components of high shear drying and / or concentrating systems, and physically removing the deposits of material and gathering the materials together.

[0099] In some embodiments, a treated material may be filtered by passing at least a portion of the treated material through one or more filtration elements (e.g., meshes of different mesh sizes, filter papers of different pore sizes, etc.), for example, positioned sequentially with each other to collect dried materials (e.g., CNF materials). In some embodiments, filtering includes passing an airflow with entrained materials (e.g., CNF materials) through one or more filtration elements so that at least a portion of entrained materials may be trapped or collected by each of the one or more filtration elements. The airflow with entrained materials may be moved through filtration elements by use of a vacuum system (e.g., a regenerative blower). In some embodiments, filtering the treated material occurs prior to collecting the filtered material. Collecting the filtered material may include removing dried material that may be deposited or accumulated on the surfaces of the one or more filtration elements. In some embodiments, physical implements may be used to remove or dislodge dried material from high shear drying and / or concentrating systems or from filtration elements, followed by gathering of the dried material in one or more containers or receptacles (e.g., via electrostatic precipitation, a cyclone filter, a baghouse, etc.).

[0100] In some embodiments, concentrated substances produced by the high shear drying and / or concentrating method may be in concentrated liquid form (i.e., solutes in higher concentrations after processing by high shear drying and / or concentrating systems than in the initial concentrations of liquid feedstocks). In some embodiments, concentrated substances may be collected in a reservoir, which may be switched to an empty reservoir when the reservoir is filled in order to maintain continuous operations.

[0101] After dried materials are formed from high shear drying and / or concentrating methods, the dried materials may be used in subsequent procedures and methods (e.g., characterization of materials, incorporation of materials in composite materials, formation of other forms of materials, etc.)High Shear Drying and / or Concentrating Systems

[0102] The present disclosure describes high shear drying and / or concentrating systems that apply high shear forces and thermal energy to a liquid feedstock with suspended and / or dissolved materials to produce dried and / or concentrated materials. For example, cellulosic feedstocks may be dried to produce CNFs with increased nanofibrous yield compared to conventional drying methods such as spray drying or oven drying. In some embodiments, provided systems use heated, pressurized air that is injected into specialized nozzle systems to generate one or more vortices (e.g., two or more vortices, three or more vortices) of opposite directions (e.g., different directions, or same directions) into which a flow of heated liquid feedstock is introduced, so that high shear and heat are applied to the liquid feedstock. In some embodiments, the application of high shear and heat generates dried materials from liquid feedstock, where solids (e.g., fibers or particles) may be entrained in an air or gas flow. In some embodiments, a vacuum system, e.g., using a regenerative blower, pulls materials entrained in the air flow into a collection module with, optionally, multiple filtration elements, or a cyclone collector, or an electrostatic precipitator to collect the dried materials.

[0103] The present disclosure also includes methods and systems including components to enable the high shear drying and / or concentrating system to be continuously operated rather than batch operation. In some embodiments, components are included in thesystem so that cellulosic slurry can be continuously added, and so that dried materials can be continuously collected and removed.Components of High Shear Drying and / or Concentrating Systems

[0104] In some embodiments, the present disclosure describes elements of high shear drying systems, inter alia, to dry a liquid feedstock (e.g., cellulosic feedstock, biomaterial feedstock, other feedstocks) into dried materials (e.g., CNF materials, powders, solids, blocks, films, fibers, particles, etc.), or to concentrate a liquid feedstock into concentrated liquids. FIG. 5 shows an exemplary process flow diagram of a high shear drying and / or concentrating system 100, according to aspects of the present embodiments. In some embodiments, the drying and / or concentrating system 100 includes an input module 101 for receiving liquid feedstock. In some embodiments, the input module 101 includes feed reservoirs 112, 114 into which the liquid feedstock may be initially loaded. The reservoirs 112, 114 are pressurized by a gas cylinder 106 via valves 108, 110. In some embodiments, the flow of cellulosic feedstock out of the reservoirs 112, 114 is combined via a connection 116 (e.g., a valve, a T connection, etc.). In some embodiments, the reservoir being used to feed the system can be selected, so that a depleted reservoir can be refilled while a filled reservoir is used, thus enabling continuous operation. The flow of liquid feedstock may be further controlled by another valve 128. Pumps 124, 126 (e.g., syringe pumps, gear pumps, diaphragm pumps, centrifugal pumps) are used to pump the flow of liquid feedstock, and are modulated by a controller 122 (e.g., valves, electronic controllers, etc.). In some embodiments, the pump being used to feed the system can be selected along with the selection of reservoir so that operation may be continuous. The liquid feedstock is then heated by a heater 130 (e.g., an isothermal heater or heat exchanger) so that the feedstock is at an elevated temperature (e.g., above room temperature but below the boiling point of the feedstock, e.g., about 95 °C). In some embodiments, the feedstock may be heated to about 80 °C, about 85 °C, or about 90 °C. In some embodiments, the feedstock may be heated to just below the boiling point of the solvent of the feedstock, which may be above the atmospheric boiling point for a pressurized feedstock. In some embodiments, the feedstock is heated by a heater 130 connected to an exterior surface of hoses or tubes used to carry the feedstock.

[0105] Referring still to FIG. 5, the high shear drying and / or concentrating system 100 also may include a turbulence module 141 to generate heated, turbulent air or gas flow, which may include a specialized feed nozzle 140, and a source of heated, pressurized air or gas. The heated, pressurized air or gas may be from ambient air 102 that is compressed using a compressor 104 and heated using heaters 118, 120. In some embodiments, the heaters 118, 120 are applied to the exterior of tubes or hoses used to carry the compressed air or gas. In some embodiments, heaters may be in-line (e.g., wires e.g., nickel chromium wires) in an interior of tubes or hoses carrying compressed air or gas that directly heat the air or gas. In some embodiments, the temperature of heated, compressed air or gas that exits is controlled by a closed loop PID controller tuned hot for fast response. In some embodiments, one or more heaters (e.g., two or more heaters) are used. In some embodiments, each controller may be heated separately. In some embodiments, the heaters may be heat exchangers. In some embodiments, the heaters 118, 120 may be block heaters. In some embodiments, the air or gas flow is divided into two separate flows that may be heated to two different temperatures, where the temperature of each air or gas flow may range between about 250 °C and 450 °C. In some embodiments, the air or gas flow is optimized to be about 375 °C (e.g., between about 350 and 400 °C).

[0106] Referring still to FIG. 5, in some embodiments, the turbulence module 141 includes two vortex generators. The first vortex generator includes an injector nozzle (e.g., a fuel injector nozzle) to generate a primary vortex when pressurized air or gas is fed into it. The second vortex generator includes two cylinders disposed coaxially around the injector nozzle, the inner cylinder with radial holes (e.g., slots, slits, angled holes, nozzles, etc.) disposed around its circumference to generate a secondary vortex when pressurized air or gas is fed into the gap between the two cylinders (i.e., a plenum chamber). In some embodiments, an injector nozzle does not have pressurized air or gas fed into it. In some embodiments, the heated feedstock is fed into the turbulence module 141 such that the feedstock first enters the primary vortex, then enters the secondary vortex. In some embodiments, the secondary vortex rotates in a direction opposite (e.g., or the same) to the primary vortex. In some embodiments, high shear is generated in the two vortices. In some embodiments, a first vortex and a second vortex are formed by two nozzles facing each other, i.e., non-counter- rotating nozzles. In some embodiments, the turbulence module 141 includes a venturi plate downstream of the first vortex generator and second vortex generator such that the feedstockpasses through the venturi plate after exiting the secondary vortex. In some embodiments, the venturi plate includes a restriction of 0.40” diameter (e.g., 0.2” diameter, 0.3” diameter, 0.35” diameter) with an inlet port of 0.45” diameter and an outlet port of 0.54” diameter; both the inlet and outlet ports may be tapered at 10° (e.g., 5°, 15°). In some embodiments, additional vortices may be included so that air or gas flow containing entrained materials may exit the secondary vortex and enter additional vortices (e.g., a third vortex, a fourth vortex, etc.) so that additional high shear is applied to the cellulosic feedstock. In some embodiments, turbulence may be generated by other means, e.g., mechanical means (e.g., blades, impellers, stators).

[0107] Referring still to FIG. 5, the materials are entrained in the air or gas flow exiting the turbulence module 141 and enters a canister 142. In some embodiments, the canister 142 may be made of stainless steel, and have a length of about 12” (e.g., about 1”, about 11”, about 13”, about 14”) and a diameter of about 11.7” (e.g., about 11”, about 11.5”, about 12”, about 12.5”). In some embodiments, the canister 142 is in such a configuration as to allow for expansion of gases and product. In some embodiments, some latency is required for product (i.e., liquid) to evaporate, in preferably as short a distance and a short a latency as possible, in order to generate explosively turbulent evaporation. In some embodiments, the canister 142 may include a viewing port and an access port, where the viewing port may be used for visual monitoring and quantification or measurement of the nozzle performance.

[0108] Referring still to FIG. 5, the air or gas flow with entrained materials then enters a collection module 151 which may include a vacuum system (e.g., regenerative blower 152) to pull the air or gas through a series of meshes 148 and filter papers 144, 146. In some embodiments, the meshes may be at least one mesh (e.g., at least two meshes, at least three meshes, at least four meshes, at least five meshes, at least six meshes). In some embodiments, the meshes may have mesh sizes 100 (0.15 mm openings), 200 (0.075 mm openings), 400 (0.0385 mm openings), and 1000 (0.015 mm openings). In some embodiments, the filter papers are stacked between meshes. In some embodiments, the filter papers 144, 146 may have pore sizes that may be between 20 to 50 microns (e.g., above 20 microns, above 50 microns, above 100 microns, below 20 microns, below 10 microns, below 2.5 microns, below 1 micron). In some embodiments, the filter papers 144, 146 may have pore sizes that are selected based on the structures and / or dimensions of suspended materials in liquid feedstock being dried. In some embodiments, the collection module 151 may havetwo filter papers and four meshes, with the first mesh (mesh size 100) placed at the open downstream end of the canister, followed sequentially by the first filter paper, the mesh size 200 mesh, the second filter paper, the mesh size 400 mesh, and the mesh size 1000 mesh. In some embodiments, the dried material (e.g., CNF material) 150 may be collected at the filter papers 144, 146, meshes 148, and canister 142. In some embodiments, the drying and / or concentrating system 100 may also include a HEPA filter 154 for environmental control, positioned downstream of the regenerative blower 152.

[0109] In some embodiments, high shear drying and / or concentrating systems may have collection modules that include collection reservoirs for collecting concentrated substances from liquid feedstock with dissolved substances. In some embodiments, concentrated substances that are produced by high shear drying and / or concentrating systems may be in liquid phase (e.g., viscous liquid, paste, fluid, low viscosity fluid, etc.) that are collected in collection reservoirs. In some embodiments, liquid solvents removed from liquid feedstocks by high shear drying and / or concentrating systems may be collected in solvent collection modules.

[0110] In some embodiments, the drying and / or concentrating system 100 may include multiple pressure sensors, temperature sensors, humidity sensors, and flow rate sensors on the air or gas flow and feedstock flow. These sensors monitor the system during a drying and / or concentrating process. In some embodiments, the humidity in the system is related to the degree of drying and / or concentrating of the feedstock as liquid (e.g., water) is removed. In some embodiments, the differential pressure drop across the collection module is monitored to determine when a certain quantity of material has been dried and collected (e.g., indicating clogging of the meshes 148 and filter papers 144, 146 due to buildup of dried material).

[0111] FIG. 6 is a photograph of an exemplary high shear drying and / or concentrating system 200, according to aspects of the present embodiments. FIG. 6 depicts a prototype implementation of the system shown in FIG. 5. In some embodiments, the system 200 includes a variable frequency drive (VFD) 202 controlled by a power switch 204 to drive the regenerative blower 206. In some embodiments, pressure valves 208, 210 are used at the feed inlet and outlet. In some embodiments, pressure gauges 212, 214, 215 are used to monitor pressure at different points in the system, including at feed reservoirs 216, 217. Insome embodiments, the pressure and / or flow rate of the air or gas delivered to generate the primary vortex and secondary vortex are measured by gauges 220, 222. In some embodiments, the flow of pressurized gas into the primary vortex and secondary vortex are controlled by the number of turns on individual valves 218, 223 (e.g., truncated cone valves, ball valves). In some embodiments, the gas flows are directed into a turbulence module (e.g., feed nozzle 224, custom nozzle), which is mounted in the side of a cylindrical canister 228. In some embodiments, the feed nozzle 224 may include an injection nozzle and coaxially disposed cylinders for generating vortices of opposite rotational directions. The canister 228 may include a viewport 226. Details of the exemplary feed nozzle are described below referring to FIGS. 7-14. In some embodiments, all valves and sensors may be computer controlled to optimize drying and / or concentrating efficiency.

[0112] In some embodiments, solvents that are removed from liquid feedstock may be cooled, collected and re-used or collected as product (e.g., water may be collected from salt water, so that the drying and / or concentrating system acts as a desalination system). In some embodiments, solvents may be collected in solvent collection modules.

[0113] Referring still to FIG. 6, the drying and / or concentrating system 200 may include a series of meshes and filter papers stacked together 230 to form a collection module where the dried material will be deposited. In some embodiments, collection modules may include a cyclone collector or electrostatic precipitation. In some embodiments, the stack 230 may include two filter papers and four meshes. In some embodiments, dried material may be deposited on the inner surface of the canister 228, and on each of the filter papers and meshes 230. The deposited material may be physically removed from these surfaces to be collected for further use. In some embodiments, the system may include meshes with different mesh sizes (e.g., mesh size 100, mesh size 200, mesh size 400, mesh size 1000) and filter papers with different pore sizes (e.g., between 20 to 50 microns (e.g., above 20 microns, above 50 microns, above 100 microns, below 20 microns, below 10 microns, below 2.5 microns, below 1 micron). In some embodiments, the outlet pressure at a low side of a regenerative blower is measured by a pressure gauge 238, and the inlet pressure at a high side of the regenerative blower is measured by a pressure gauge 232. In some embodiments, the pressures at the two heaters used to heat the pressured gas flows may be measured by gauges 236, 234. Not directly visible in FIG. 6 are two syringe pumps that pump the feedstock fromthe reservoirs 216, 217 into the feed nozzle 224, and a controller for running the syringe pumps (e.g., pumping speed, on / off control, etc.).Vortex Generators

[0114] In some embodiments, the drying and / or concentrating system 100, 200 includes a turbulence module 141 that includes one or more vortex generators. FIGS. 7-14 show schematic diagrams and photographs of an exemplary turbulence module 141. In accordance with various embodiments, an injection nozzle is used for generating a primary vortex (or vortex 1) while a plenum chamber with circumferential holes generates a secondary vortex (or vortex 2) which may rotate in opposite directions and generate the high shear needed to separate dispersed materials in the liquid feedstock (e.g., cellulosic fibers) and to evaporate solvent. In some embodiments, the circumferential holes may be slots, slits, angled holes, nozzles, etc., or other openings that may help to accelerate the air or gas flow by forcing the air or gas through constrictions. In some embodiments, these openings may accelerate the air or gas to high velocities (e.g., supersonic velocities).

[0115] FIG. 7 is a schematic diagram of a turbulence module 141 according to aspects of the present embodiments. Liquid feedstock enters the turbulence module 141 via connector 302 from the reservoirs holding feedstock. The feedstock entering at connector 302 is heated so that it has additional heat but is below boiling (e.g., to about 95 °C for an aqueous feedstock) to avoid gas bubbles. In some embodiments, the feedstock is heated to higher temperatures (e.g., as high as 200 °C for cellulosic feedstock) that are above the atmospheric boiling points of solvents used in liquid dispersions (e.g., when liquid dispersions are pressurized so that their boiling points are increased). Hot air 304 enters the input end of an injection nozzle 308 (e.g., a fuel injection nozzle), which is held by a flange 306. In some embodiments, the bore of the injection nozzle can vary from 1 mm and above. A vortex (i.e., primary vortex or vortex 1) forms inside the injection nozzle 308, where the feedstock entering the connector 302 encounters the vortex. The injection nozzle 308 fits coaxially inside the inner cylinder 312. The hot air or gas and entrained materials exit vortex 1, and enter vortex 2. Hot air 320 enters the space between the inner cylinder 312 and outer cylinder (i.e., the plenum chamber) via another inlet connector (not shown here, but shown in FIGS. 9-14), and passes through a plurality of circumferential holes (e.g., slots, slits, nozzles, angled holes, tapered holes, etc.) drilled in the inner cylinder 312 to form another vortex (i.e.,secondary vortex or vortex 2), which rotates in the opposite direction to vortex 1. The inner cylinder 312 is perforated with holes 314 (e.g., 8 holes, e.g., 6 holes, e.g., 10 holes, e.g., 12 holes) around its circumference pointing radially, which help to generate the vortex and allow the hot air and entrained materials from vortex 1 to enter vortex 2. In some embodiments, the injection nozzle 308 may be replaced by another structure similar to the inner cylinder 312 with holes 314. The hot air and materials exiting from vortex 2 pass out through a flange 316 (e.g., sanitary flange), which is held in place by screws 318. There are also screws 311 in the base of flange 310.

[0116] FIG. 8 is a schematic diagram of another embodiment of a turbulence module 141B, according to aspects of the present embodiments. Turbulence module 141B differs from turbulence module 141 in that there is an additional venturi plate 416 positioned immediately downstream of vortex 2. Liquid feedstock enters the turbulence module 141B via connector 402 from the reservoirs holding feedstock. The feedstock entering at connector 402 is heated so that it has additional heat but is below boiling (e.g., to about 95 °C for an aqueous feedstock). In some embodiments, the feedstock may be heated to above the atmospheric boiling point of the solvent of the liquid feedstock. Hot air 404 enters the input end of an injection nozzle 408 (e.g., a fuel injection nozzle), which is held by a flange 406. A vortex (i.e., primary vortex or vortex 1) forms inside the injection nozzle 408, where the feedstock entering the connector 402 encounters the vortex. The injection nozzle 408 fits coaxially inside the inner cylinder 412. Hot air 420 enters the space between the inner cylinder 412 and outer cylinder via another inlet connector (not shown here, but shown in FIGS. 9-14) and passes through plurality of circumferential holes drilled in the inner cylinder 412 to form another vortex (i.e., secondary vortex or vortex 2), which rotates in the opposite direction to vortex 1. The inner cylinder 412 is perforated with holes 414 (e.g., 8 holes, e.g., 6 holes, e.g., 10 holes, e.g., 12 holes) around its circumference pointing radially, which help to generate the vortex and allow the hot air or gas and materials from vortex 1 to enter vortex 2. The hot air or gas and materials exiting from vortex 2 then enter a venturi plate 416, which has an opening that narrows in the interior. In some embodiments, the venturi plate 416 may have a restriction of 0.40” diameter with an inlet port of 0.45” diameter and an outlet port of 0.54" diameter, with both the inlet and outlet ports tapered at 10°. The venturi plate 416 is held in place by screws 418. The hot air or gas and entrained dried materials exiting from the venturi plate 416 pass out through a flange 422 (e.g., sanitary flange), which is held in place by screws 420. There are also screws 411 in the base of flange 410.

[0117] FIG. 9 is a side view computer-aided design (CAD) diagram of an exemplary turbulence module 141, according to aspects of the present embodiments. Pressurized, heated air enters connector 504 connected to the injection nozzle 506 to form the primary vortex (vortex 1), and enters connector 520 connected perpendicularly to the side of the outer cylinder 518, and exits through a plurality of circumferential holes in the inner cylinder 516 to form the secondary vortex (vortex 2). The liquid feedstock enters the connector 502, which is connected perpendicularly to the side of the injection nozzle 506. A custom-built housing portion includes the outer cylinder 518 (which along with the inner cylinder 516 form a plenum chamber in the gap between the inner cylinder 516 and outer cylinder 518), tapped mating flange 520, flange 524, and exit tube or expansion tube 522.

[0118] FIG. 10 is another side view CAD diagram of a turbulence module 141, according to aspects of the present embodiments. The view in FIG. 10 is rotated slightly from the view in FIG. 9.

[0119] FIG. 11 is an exploded side view CAD diagram of the components of a turbulence module 141, according to aspects of the present embodiments. The view of FIG. 11 shows how the various components of an exemplary turbulence module 141 fit together. The injection nozzle 507 includes an air-liquid diverter 508, tapered endplate 510, and nozzle end nut 512. The tapered endplate 510 fits onto the nozzle of the air-liquid diverter 508, and the nozzle end nut 512 screws onto threads on the exterior of the air-liquid diverter 508, which then fits inside the outer housing 506. The assembled injection nozzle 507 then fits inside the inner cylinder 516, which fits inside the outer cylinder 518. In some embodiments, the inner cylinder 516 includes a plurality of radial circumferential holes (not shown). The outer cylinder 518 may include a threaded hole in its wall where connector 520 is connected. In some embodiments, the radial circumferential holes may include holes, slits, slots, nozzles, angled holes, or other openings. The gap between the inner cylinder 516 with holes and the outer cylinder 518 forms a plenum chamber, and the two cylinders together form a second vortex generator. The base of outer cylinder 518 is then screwed onto the tapped mating flange 520, which is then connected to exit tube or expansion tube 522 and further flange 524.

[0120] FIG. 12 is an exploded perspective view CAD diagram of the components of an exemplary turbulence module 141, according to aspects of the present embodiments. Theview of FIG. 12 is similar to the view of FIG. 11, but with a perspective view from an elevated viewpoint, rather than the side-on view of FIG. 11.

[0121] FIG. 13 is a cross-sectional side view CAD diagram of the components of an assembled turbulence module 141, according to aspects of the present embodiments. The same components indicated here are as described above in FIGS. 10-13. In FIG. 13, the coaxial positioning of the outer housing 506 and air-liquid diverter 508 of the injection nozzle with respect to the inner cylinder 516 and outer cylinder 518 of the plenum chamber (i.e., the second vortex generator) are visible.

[0122] FIG. 14A is a photograph of an assembled turb turbulence module 141, with injection nozzle 512 and second vortex generator comprising the inner cylinder 516 and outer cylinder 518 visible, according to aspects of the present embodiments. Holes 517 drilled in the wall of the inner cylinder 516 are also visible. In the opening tip of the injection nozzle 512, the air-liquid diverter 508 is visible.

[0123] FIG. 14B is a photograph of the inner wall 516 (or inner cylinder 516) of the plenum chamber of the turbulence module 141, which helps to form the secondary vortex in combination with the outer cylinder 518, according to aspects of the present embodiments. Radial circumferential holes 517 are visible in the wall of the inner cylinder 516. A drill bit is inserted to indicate the direction of the holes 517. In some embodiments, the radial circumferential holes are tapered (e.g., using a 7 degree tapered ream) so that the diameters of the holes at the inner surface of inner cylinder 516 may be smaller than the diameters of the holes at the outer surface of inner cylinder 516 (e.g., diameter at inner surface about 1 / 16”), each hole forming a small nozzle. The inner cylinder 516 may be made of stainless steel, and have a base for attaching to other components of the feed nozzle. In some embodiments, hole sizes, positions, angle with respect to cylinder, taper angles, shapes, and numbers drilled in inner cylinder 516 may be varied in order to tune the behavior of a secondary vortex. In some embodiments, another means of generating a secondary vortex may be used.

[0124] FIG. 14C is a photograph of an assembled turbulence module 141, with injection nozzle 512 and secondary vortex generator formed by the inner cylinder 516 and outer cylinder 518 visible, and with the primary vortex and secondary vortex indicated by the small and large curved arrows, respectively, according to aspects of the present embodiments. The primary vortex and secondary vortex are rotating in opposite directions in theembodiment shown in FIG. 14C. The plenum chamber 519 is formed by the gap between the inner cylinder 516 and the outer cylinder 518.Operating High Shear Drying and / or Concentrating System and Effect of System Parameters

[0125] Operation parameters of the high shear drying and / or concentrating system may affect the yield of dried material collected at the end of processing, and may also affect the morphology of the resulting material. FIGS. 26 and 27 show broad and detailed exemplary methods 600, 700 for the operation of a high shear drying and / or concentrating system to produce dried materials (e.g., CNF materials) and / or concentrated substances. The detailed method 700 in FIG. 27 show where various parameters may be set. These parameters may include the feed rate of the liquid feedstock, heater temperature for the compressed air or gas flows entering vortex 1 and vortex 2, the flow rates of compressed air or gas flows entering vortex 1 and vortex 2. Additional parameters include the set temperature of the liquid feedstock heater, the characteristics of the liquid feedstock such as the solvent, type of dispersed material, distribution of sizes of dispersed material, and concentration of dispersed material. For example, in a cellulosic feedstock, the relevant parameters may also include percent fines of cellulosic material in the feedstock, and the original source of the cellulosic material (e.g., the type of plant, method of processing to produce cellulosic material).

[0126] FIG. 26 is a flow chart diagram for a method 600 of high shear drying and / or concentrating to form dried materials and / or concentrated substances from materials dispersed and / or dissolved in a liquid feedstock, according to aspects of the present embodiments. The method 600 is a general method, and may include the following steps: step 602, providing a liquid feedstock; step 604, heating the liquid feedstock; step 606, exposing the liquid feedstock to a high shear environment to form treated material; and step 608, collecting the treated material. In some embodiments, the liquid feedstock may be a cellulosic feedstock. In some embodiments, a high shear environment may be a heated, turbulent airflow. In some embodiments, treated material may include a plurality of cellulose nanofibrils that are substantially not aggregated.

[0127] FIG. 27 is a flow chart diagram for an exemplary method 700 of high shear drying and / or concentrating to form dried and / or concentrated materials from a dispersion and / or solution in a liquid feedstock, according to aspects of the present embodiments. The method 700 is a detailed method, and may include the following steps: step 702, assemble parts of collection system; step 704, wash injection nozzle to remove residues from previous run; step 706, load liquid feedstock into feed reservoirs; step 708, pressurize feed reservoirs with gas; step 710, turn on syringe pumps and set flow rates; step 712, charge syringe pumps with feedstock; step 714, turn on feedstock heater and set temperature; step 716, turn on humidity data recording; step 718, turn on regenerative blower by turning on variable frequency drive (VFD); step 720, open valves to introduce compressed air into injection nozzle to create vortex 1, and into plenum chamber to generate vortex 2; step 722, turn on inline heaters to heat compressed air entering vortices; step 724, run syringe pumps to start the flow of feedstock; step 726, monitor pressure of system, where end of run is determined by increase in differential pressure across filter assembly (e.g., 70 inch water pressure); step 728, turn off heaters and air valves and cool system for 5 minutes; step 730, dismantle collection system and recover dry material from filter papers and mesh screens; and step 732, clean and flush system (i.e., vent and flush system with water multiple times).

[0128] The following parameters were varied to determine their effect on yield and morphology of CNFs produced by a high shear drying and / or concentrating system as applied to a cellulosic feedstock:• Feed rate of cellulosic feedstock: 10 ml / min, 20 ml / min, and 30 ml / min were used, with the 10 ml / min feed rate producing the highest nanofibrous product yield with the most non-aggregated morphology• Compressed air or gas flow rate for vortex generation: two truncated cone valves control the flow of air into the injection nozzle for vortex 1 generation, and into the plenum chamber for vortex 2 generation were opened by varying numbers of turns. Valve openings of 1, 1.5, 2, and 2.5 turns were used, resulting in the optimal nanofibrous yield at 2 turns open on each of the compressed air control valves. An example of valve openings and flow rates are summarized in the table below.• Vortex temperature: the set-point temperatures of the in-line heaters for the lines supplying air or gas for each of vortex 1 and vortex 2 were adjusted over the range of 250 °C to 375 °C, with the optimal vields achieved when both vortex temperatureswere set to 375 °C. The morphology did not significantly differ at different temperatures, but the yield (i.e., quantity collected) of nanofibrous material was maximized at 375 °C for both vortices.• Percent fines: feedstock including between 90% and 100% fines was used, with a higher yield of nanofibrous product for the 100% fines feedstock. Percent fines refers to the percentage of fibers in a sample that are less than 200 micrometers in size (e.g., not detected optically by a morphological analyzer). The 90% fines indicates that 90% of the fibers are <200 microns. For the 90% fines to reach 100% fines would mean the CNF slurry has been run through additional refining loops, eventually reaching a point where 100% of the fibers are <200 microns.• Cellulosic source: cellulosic feedstock made from flax produced similar results as cellulosic feedstock made from Northern softwood bleached kraft pulp. Most of the results disclosed herein were from materials generated from cellulosic feedstock made from Northern softwood bleached kraft pulp.Continuous Operation of High Shear Drying and / or Concentrating System

[0129] In some embodiments, provided high shear drying and / or concentrating systems may be modified by adding or changing components so that it may be operated in a continuous fashion with minimal stopping for adding liquid feedstock or removing processed material.

[0130] Continuous provision of liquid feedstock can be achieved by using one or more input reservoirs. In some embodiments, two input reservoirs holding liquid feedstock each with a transport mechanism (e.g., a pump) are used to provide input to the high shear drying and / or concentrating system. The high shear drying and / or concentrating system may be fed first by one input reservoir and a pump, and when that reservoir runs low of liquid feedstock, the system can switch to the second input reservoir and either the same pump or a second pump while the first reservoir is refilled. The two reservoirs can be repeatedly switched between providing input to the drying and / or concentrating system and being refilled. More than two reservoirs (i.e., multiple reservoirs) can be used in this manner of switching between feeding and refilling, with multiple pumps as needed, which can be set to switch to active reservoirs automatically, and can also be used to refill depleted reservoirs. In some embodiments, positive displacement pumps may be used for transporting liquid feedstock out of a reservoir (e.g., a syringe pump, a gear pump, a diaphragm pump, a centrifugal pump). In some embodiments, alternative delivery mechanisms may be used to provide liquid feedstock to high shear drying and / or concentrating systems.

[0131] Clogging of the feed nozzle may occur as dried material builds up during the drying and / or concentrating process. The feed nozzle also heats up during the drying and / or concentrating process as hot air or gas and heated feedstock enter into it. Continuous operations can be implemented by switching between multiple nozzles (e.g, by monitoring system pressure for an increase in pressure associated with partial nozzle clogging, and then switching to a new nozzle, so that the first nozzle can be cleaned). In some embodiments, valves may be added so that feed nozzles may be valved off and changed while other nozzles are in use.

[0132] Continuous removal of dried material or concentrated substances is also needed for continuous operation. For example, buildup of dried material on the meshes and filter papers can cause blockages or clogs. In some embodiments, a bag house may be used at the collection module to periodically tap and shake the filters to drop and collect dried material. In some embodiments, an electrostatic precipitator may be used to collect dried material. In some embodiments, a centrifugal collection system may be used to collect dried material. In some embodiments, filled filter papers and meshes can be swapped for clean ones. In some embodiments, monitoring the differential pressure drop across the filters and meshes can be used to indicate when a collection step may need to be implemented to collectbuilt-up dried material. In some embodiments, reservoirs to collect concentrated liquids may be swapped for empty reservoirs (e.g., using one or more valves to control the flow of liquids during a swapping procedure) for continuous operation. These methods can be implemented largely without significant interruptions to a continuous drying and / or concentrating process.Characterization of CNFs from High Shear Drying and / or Concentrating System

[0133] Dried CNFs from a high shear drying and / or concentrating system can be collected as a dry material (e.g., a powder, a solid, etc.) when the drying process is complete (e.g., when an increase in differential pressure in the collection module of filter papers and meshes is measured, or when a desired amount of dried CNF product has been collected). Scanning electron microscopy (SEM) was used to assess the degree of nanostructure maintenance and aggregation in the collected CNF material, and to measure the nanofibrils’ diameters and lengths. FIGS. 15-18 are SEM images of CNFs from high shear drying under varying processing conditions (e.g., vortex air or gas temperature, vortex air or gas flow rate, cellulosic feedstock flow rate, etc.). The samples featured in FIGS. 15-18 were collected from the first filter paper, where the largest proportion of CNF material was deposited.

[0134] FIG. 15 is an SEM image of CNF material from high shear drying showing nanofibrils, according to aspects of the present embodiments. The sample imaged in FIG. 15 was collected from the first filter paper of the collection module of the high shear drying system. The image shows many nanofibrous structures of narrow diameters and long lengths. The processing conditions and yields corresponding to the sample shown in FIG. 15 are summarized below:

[0135] FIG. 16 is an SEM image of CNF material from high shear drying showing nanofibrils, according to aspects of the present embodiments. The sample imaged in FIG. 16 was collected from the first filter paper of the collection module of the high shear drying system. The same conditions were used as in the drying procedure to generate the CNF material imaged in FIG. 15, but with a higher flow rate. The image shows many nanofibrous structures of narrow diameters and long lengths, as well as some thicker rope-like structures that may be some nanofibrils that have come together or may be pulp fibers that were not fibrillated. The processing conditions and yields corresponding to the sample shown in FIG. 16 are summarized below.

[0136] FIG. 17 is an SEM image of CNFs from high shear drying showing nanofibrils, according to aspects of the present embodiments. The sample imaged in FIG. 17 was collected from the first filter paper of the collection module of the high shear drying system, and was produced during experiments where drying conditions were being varied. In this particular example, the in-line heaters heating the compressed air lines supplying pressurized gas into the feed nozzle to generate vortex 1 and vortex 2 were both set to 375 °C, and the air flow rate was increased by opening the valve controlling hot air flow to more turns. The processing conditions and yields corresponding to the sample shown in FIG. 17 are summarized below.

[0137] FIG. 18 is an SEM image of CNFs from high shear drying showing nanofibrils and globular features, according to aspects of the present embodiments. The processing conditions and yields corresponding to the sample shown in FIG. 18 are summarized below. Lower vortex air temperatures were used here than in the process that led to the images in FIG. 17. These conditions do not produce optimized nanofibrous material, as there are globular features visible in FIG. 18, and the yields are lower than from other conditions that are more optimized.

[0138] FIGS. 19A, 19B, 19C, and 19D are histograms of fibril diameters from SEM images of CNFs from high shear drying, according to aspects of the present embodiments. These data were compiled by imaging CNFs from multiple different experiments. Multiple individual SEM images from 17 individual runs were used, and the diameters of CNFs in each SEM image were measured and tabulated. These data show that the CNFs are predominantly below 500 nm in diameter (82% of nanofibrils under 500 nm), with a large proportion below 200 nm in diameter (50% of nanofibrils under 200 nm), and smaller proportion below 100 nm in diameter (16% of nanofibrils under 100 nm). The peak in the histogram for smaller diameters appears at 80-120 nm diameter.Mechanical Reinforcement of Polymers by CNFs

[0139] The CNF material formed by provided high shear drying methods described herein may be used to provide mechanical reinforcement of polymers such as polylactic acid (PLA). In some embodiments, CNF material may be incorporated into PLA by melt mixing or compounding using a shear mixer. The incorporation of CNFs into PLA results in improvement of mechanical properties of the PLA by providing mechanical reinforcement through the CNF fibers. In some embodiments, CNF fibers may be coated and / or chemically modified or activated during drying so that they may be thermally bonded into shapes or for other needs. In some embodiments, CNF fibers may be carbonized and may be used for adsorptive chemistry, having very high specific surface area.

[0140] FIG. 28 is a flow chart diagram for an exemplary method 800 for forming a composite material that includes CNFs, according to aspects of the present embodiments. In some embodiments, the method 800 may include the following steps: step 802, obtaining a quantity of CNF material (e.g., CNF material dried by high shear drying method, or by another drying method such as spray drying); step 804, obtaining a quantity of polymer pellets; step 806, drying the CNF material and polymer pellets at a drying temperature (e.g., 60 °C) (or e.g., 55 °C, 65 °C, 70 °C); step 808; loading the polymer pellets into a shear mixer; step 810, operating the shear mixer (e.g., at 175 °C and 70 rpm for 3 min) containing the polymer pellets; step 812, loading the CNF material into the shear mixer; step 814, operating the shear mixer (e.g., at 175 °C and 70 rpm for 5 min) containing the polymer pellets and the CNF material; and step 816, removing a product from the shear mixer, i.e., the product comprising the composite material of the polymer and the CNF material. In some embodiments, the polymer used in method 800 may include at least one of polylactic acid (PLA), a thermoplastic polymer, polyethylene, polypropylene, or nylon.

[0141] FIG. 20A is a photograph of neat polylactic acid (PLA), according to aspects of the present embodiments. The PLA shown in FIG. 20A is after compounding. FIG. 20B is a photograph of PLA compounded with CNFs from high shear drying, according to aspects of the present embodiments.

[0142] FIG. 21 is a photograph of tensile bars of neat PLA in dogbone Type V shapes for ASTM D638 tensile testing, according to aspects of the present embodiments. The tensile bars were formed via compressing molding using a hot press. Prior to hot press molding, the compounded PLA / CNF materials were oven dried at 60 °C for at least 12 h to remove any moisture from the material. Test samples were produced in a two-step process. First, an initialsheet of composite material was pressed between a pair of 6” x 6” metal plates, cut into strips, and placed on top of molds of 4” x 1”. Second, a final press was used to create the tensile bars of 2.5” length x 0.38” width x 0.13” thickness.

[0143] FIGS. 22A, 22B, 22C, and 22D are photographs of tensile bars of PLA compounded with, respectively, 5 wt%, 10 wt%, 20 wt%, and 30 wt% CNFs from high shear drying in dogbone Type V shapes for ASTM D638 tensile testing, according to aspects of the present embodiments. These tensile bars were formed using the method described above. The CNFs used in these samples were dried using the high shear drying method, and collected from the first filter paper of the collection module. The CNFs were imaged by SEM prior to compounding with PLA in order to assess the extent of nanofibrous morphology. CNF material samples collected from multiple runs of the high shear dryer were aggregated into a single mass, which was used for compounding and compression molding of tensile bars.

[0144] FIGS. 23 A, 23B, 23C, and 23D are photographs of tensile bars of PLA compounded with, respectively, 5 wt%, 10 wt%, 20 wt%, and 30 wt% CNFs from spray drying in dogbone Type V shapes for ASTM D638 tensile testing, according to aspects of the present embodiments. These composites using spray dried CNF were made using a similar method as described above for the high shear dried CNF. Spray dried CNF have much less nanofibrous morphology, as the drying of droplets forms more globular structures (see FIG. 4C), which are less beneficial for mechanical reinforcement of polymers.

[0145] FIGS. 24A and 24B are plots of ultimate tensile strength (UTS) for PLA compounded with varying concentrations of CNFs from spray drying (SD) and high shear drying (HSD), according to aspects of the present embodiments. In both FIG. 24A and 24B, the error bars represent 95% confidence limits. The UTS values of the composite materials were determined by the maximum load divided by the original cross-sectional area:Cmax Pmax / Ao where Pmax = maximum load, and Ao = original cross-sectional area of the tensile bars. The UTS shows an increasing trend with increasing concentration of high shear dried CNF, but no significant change or even a slightly decrease was seen with spray dried CNF. However, samples denoted as “A” were determined to be statistically the same.

[0146] FIGS. 25A and 25B are plots of tensile modulus for PLA compounded with varying concentrations of CNFs from spray drying (SD) and high shear drying (HSD),according to aspects of the present embodiments. These results indicate that the tensile modulus increases with increasing concentration of CNF from both spray drying and high shear drying, but that the rate of increase is higher for high shear dried CNFs. In FIGS. 25A and 25B, the error bars represent 95% confidence limits. In FIG. 25B, groups labelled by different letters are significantly different by a = 0.05. Without being bound to any particular theory, the higher nanofibrous content of CNFs from high shear drying serves to more effectively provide mechanical reinforcement of the polymer matrix.EQUIVALENTS

[0147] Those skilled in the art will recognize, or be able to ascertain using no more than routine experimentation, many equivalents to the specific embodiments of the invention described herein. The scope of the present invention is not intended to be limited to the above Description, but rather is as set forth in the following claims:

Claims

CLAIMSWhat is claimed:

1. A method for producing dried cellulose nanofibril (CNF) material, comprising: providing a cellulosic feedstock; heating the cellulosic feedstock; exposing the cellulosic feedstock to a high shear environment to form treated material; and collecting the treated material, wherein the treated material comprises a plurality of cellulose nanofibrils, and wherein the cellulose nanofibrils are substantially not aggregated.

2. The method of claim 1, wherein the high shear environment comprises a heated, turbulent air flow or gas flow.

3. The method of claim 1, wherein the heating and exposing happen substantially simultaneously.

4. The method of claim 1, wherein the method additionally comprises filtering the treated material to form filtered material.

5. The method of claim 4, wherein filtering comprises passing at least a portion of the treated material through meshes, filter papers, or combinations thereof.

6. The method of claim 1, wherein the cellulosic feedstock comprises at least 50% fines (e.g., at least 60% fines, 70% fines, 80% fines, 85% fines, 90% fines, 95% fines, 99% fines, 100% fines).

7. The method of claim 1, wherein heating the feedstock is to about 95 °C (e.g., about room temperature, about 80 °C, about 85 °C, about 90 °C).

8. The method of claim 1, wherein heating the feedstock is to about the boiling point of the feedstock.

9. The method of claim 2, wherein the heated, turbulent airflow is heated to about 375 °C (e.g., about 250 °C, about 275 °C, about 300 °C, about 325 °C, about 350 °C, about 400 °C, about 425 °C, about 450 °C).

10. The method of claim 1, wherein at least 20 wt% of the cellulosic feedstock are collected as cellulose nanofibrils by end of the method (e.g., at least 30 wt%, 40 wt%, 50 wt%, 60 wt%, 70 wt%, 80 wt%, 90 wt%).

11. The method of claim 1, wherein the cellulosic feedstock comprises an aqueous suspension of cellulose or lignocellulose.

12. The method of claim 11, wherein the aqueous suspension comprises at least 1 wt% cellulose (e.g., at least 2 wt%, at least 3 wt%, at least 4 wt%, at least 5 wt%).

13. The method of claim 1, wherein the cellulosic feedstock is fed into the high shear environment at a rate of about 10 ml / min (e.g., about 20 ml / min, about 50 ml / min, about 100 ml / min, about 1 L / min, about 10 L / min, about 100 L / min, about 500 L / min).

14. The method of claim 2, wherein the heated, turbulent airflow comprises one or more vortices.

15. The method of claim 14, wherein the one or more vortices are formed by at least one of a Venturi plate, a nozzle, or a plenum chamber with a plurality of perforations.

16. The method of claim 2, wherein the heated, turbulent airflow comprises a first vortex and a second vortex, wherein the first vortex and the second vortex rotate about a common axis.

17. The method of claim 1, wherein the plurality of cellulose nanofibrils comprise an average diameter below about 200 nm.

18. The method of claim 2, wherein the heated, turbulent airflow comprises a flow rate of 40 to 200 scf / h.

19. The method of claim 1, wherein providing the cellulosic feedstock comprises loading the cellulosic feedstock into at least one feed reservoir, and using at least one pump module (e.g., a syringe pump, a gear pump, a diaphragm pump, a centrifugal pump) to transport the cellulosic feedstock out of the at least one reservoir.

20. The method of claim 1, wherein collecting comprises removing and gathering dried CNF material from the high shear environment.

21. A system for drying and / or concentrating a liquid feedstock comprising at least one liquid solvent and a quantity of dispersed materials and / or dissolved solutes, comprising: an input module for receiving the liquid feedstock; a turbulence module functionally connected to the input module; a collection module functionally connected to the turbulence module; a first heat source functionally connected to an outflow of the input module; anda second heat source functionally connected to a pressurized input gas flow into the turbulence module.

22. The system of claim 21, wherein the turbulence module is functionally connected to a source of heated, pressurized gas.

23. The system of claim 21, wherein the input module comprises: at least one feed reservoir fluidly connected to a pump module (e.g., syringe pump).

24. The system of claim 23, wherein the input module further comprises: at least one pressurized gas source (e.g., compressed gas cylinder, ambient air with compressor); and a plurality of valves to control flow of gas between the at least one feed reservoir and pump, and the at least one pressurized gas source.

25. The system of claim 21, wherein the turbulence module comprises a nozzle.

26. The system of claim 25, wherein the turbulence module further comprises a venturi plate.

27. The system of claim 21, wherein the system further comprises a vacuum system (e.g., a regenerative blower, or a vacuum pump) functionally connected downstream of the collection module.

28. The system of claim 21, wherein the collection module comprises one or more (e.g., two or more) filter papers and one or more (e.g., two or more, three or more, four or more) meshes, wherein the one or more filter papers and the one or more meshes are stacked together.

29. The system of claim 28, wherein the one or more filter papers comprise a first filter paper, and a second filter paper.

30. The system of claim 28, wherein the one or more meshes comprises four meshes comprising mesh sizes of 100, 200, 400, and 1000.

31. The system of claim 21, wherein the first heat source comprises a heat exchanger.

32. The system of claim 21, wherein the second heat source comprises a heat exchanger.

33. The system of claim 21, wherein the collection module comprises a reservoir to collect concentrated substances.

34. The system of claim 21, wherein the turbulence module comprises: an injector nozzle; a plenum chamber comprising a first cylinder disposed coaxially around the fuel injector nozzle, the first cylinder comprising a plurality of radial holes (e.g., slots, angled holes, nozzles, tapered holes), and a second cylinder disposed coaxially around the first cylinder, wherein a first flow of heated, pressurized gas flow flows through the fuel injector nozzle to generate a first vortex, and wherein a second flow of heated, pressurized gas flow flows through a space between the first cylinder and the second cylinder and through the plurality of radial holes to generate a second vortex.

35. The system of claim 34, wherein the second vortex is located within an internal diameter of the first cylinder.

36. The system of claim 21, wherein the input module comprises feed reservoirs that can be refilled or swapped for continuous operation of the system.

37. The system of claim 21, wherein the turbulence module further comprises at least one of a cooling module, a flushing and / or cleaning module, or a mechanism for switching between nozzles.

38. The system of claim 21, wherein the collection module further comprises at least one of a bag house, an electrostatic precipitator, or a centrifugal collection system.

39. A composite material comprising: a polymer matrix; and a plurality of cellulose nanofibrils (CNFs) distributed throughout the polymer matrix, wherein the cellulose nanofibrils are produced by the method of claim 1.

40. The composite material of claim 39, wherein the polymer matrix comprises polylactic acid (PL A).

41. The composite material of claim 39, wherein the polymer matrix comprises at least one of a thermoplastic polymer, polyethylene, polypropylene, or nylon.

42. The composite material of claim 39, wherein the CNFs are distributed throughout the polymer matrix by melt mixing dry CNF material with pellets of the polymer matrix.

43. The composite material of claim 39, wherein the CNFs comprise a plurality of nanofibrils with diameters below about 200 nm.

44. A method for forming a composite material, comprising: obtaining a quantity of cellulose nanofibril (CNF) material; obtaining a quantity of polymer pellets; drying the CNF material and polymer pellets at a drying temperature (e.g., 60°C) for a drying duration (e.g., 12 hours) in an oven; loading the polymer pellets into a shear mixer; operating the shear mixer (e.g., at 175°C and 70 rpm for 3 minutes) containing the polymer pellets; loading the CNF material into the shear mixer; operating the shear mixer (e.g., at 175°C and 70 rpm for 3 minutes) containing the polymer pellets and the CNF material; and removing a product from the shear mixer, the product comprising the composite material of the polymer and the CNF material.

45. The method of claim 44, wherein the CNF material is obtained by the method of claim 1.

46. The method of claim 44, wherein the polymer pellets comprise polylactic acid (PLA).

47. The method of claim 44, wherein the polymer pellets comprise at least one of a thermoplastic polymer, polyethylene, polypropylene, or nylon.

48. The method of claim 44, wherein the CNF material comprises a plurality of nanofibrils with average diameters below about 200 nm.

49. A method for drying and / or concentrating a liquid feedstock, comprising: providing a liquid feedstock;exposing the liquid feedstock to a high shear environment to form treated material; and collecting the treated material.

50. The method of claim 49, wherein the method further comprises heating the liquid feedstock.

51. The method of claim 49, wherein the liquid feedstock comprises one or more liquid solvents and a plurality of suspended materials and / or dissolved substances.

52. The method of 51, wherein the suspended materials and / or dissolved substances comprise at least one of cellulosic materials, polysaccharides, viruses, nucleic acids, proteins, milk, salts, black liquor, lignin, maple sap, or pharmaceuticals.

53. The method of claim 49, wherein the high shear environment comprises a heated, turbulent air flow.

54. The method of claim 49, wherein the heating and exposing happen substantially simultaneously.

55. The method of claim 49, wherein the method additionally comprises filtering the treated material to form filtered material.

56. The method of claim 55, wherein filtering comprises passing at least a portion of the treated material through meshes, filter papers, or combinations thereof.

57. The method of claim 50, wherein heating the liquid feedstock is to about or above a boiling point of the liquid feedstock (e.g., within 5 degrees Celsius of the boiling point,within 10 degrees Celsius of the boiling point, within 15 degrees Celsius of the boiling point).

58. The method of claim 53, wherein the heated, turbulent airflow is heated to about 375 °C (e.g., about 250 °C, about 275 °C, about 300 °C, about 325 °C, about 350 °C, about 400 °C, about 425 °C, about 450 °C).

59. The method of claim 49, wherein the liquid feedstock is fed into the high shear environment at a rate of about 10 ml / min (e.g., about 20 ml / min, about 30 ml / min, about 50 ml / min, about 100 ml / min).

60. The method of claim 53, wherein the heated, turbulent airflow comprises one or more vortices.

61. The method of claim 60, wherein the one or more vortices are formed by at least one of a Venturi plate, a nozzle, or a plenum chamber with a plurality of holes.

62. The method of claim 53, wherein the heated, turbulent airflow comprises a first vortex and a second vortex, wherein the first vortex and the second vortex rotate about a common axis in opposite directions.

63. The method of claim 53, wherein the heated, turbulent airflow comprises a first vortex and a second vortex, wherein the first vortex and the second vortex rotate about a common axis in the same direction.

64. The method of claim 53, wherein the heated, turbulent airflow comprises a flow rate of 40 to 200 scf / h.

65. The method of claim 49, wherein providing the liquid feedstock comprises loading the liquid feedstock into at least one feed reservoir, and using at least one pump module (e.g., a syringe pump, a gear pump, a diaphragm pump, a centrifugal pump) to transport the liquid feedstock out of the at least one reservoir.

66. The method of claim 49, wherein collecting comprises removing and gathering dried material and / or concentrated substances that have been exposed to the high shear environment.