Method and apparatus for recovering fibers

Abstract

An apparatus for recovering separated fibers from a biomass composite material, such as engineered wood material, is described. The apparatus has a channel configured to receive a slurry including water and the biomass composite material, two or more conveyor belts configured to move the slurry through the channel, whereby the biomass composite material is placed between the two conveyor belts, and a plurality of electrodes disposed within the channel, configured to apply an electric current to the slurry to heat the biomass composite material and achieve separation of the fibers in the biomass composite material; and recovering the separated fibers. A method for recovering the separated fibers is also described.

Description

[Technical field]

[0001] The present invention relates to the recovery and recycling of separated fibers from biomass composites, and more particularly from engineered wood products such as fiberboards and particleboards. More particularly, the present invention relates to a novel apparatus and method that uses ohmic heating to facilitate the recovery and recycling of separated fibers. [Background technology]

[0002] Biomass composites, such as engineered wood materials, are commonly used raw materials for many applications, including furniture manufacturing, articulation and construction. These materials contain a matrix of biomass fibers reinforced by the addition of resins or adhesives. Prominent examples of these materials are particleboard, medium density fiberboard (MDF) and high density fiberboard (HDF).

[0003] Biomass composites are widely used and are typically cheaper, denser and more uniform than untreated biomass materials such as conventional wood. However, over time these materials can be susceptible to swelling and discolouration due to moisture absorption. A key issue is that these materials do not readily lend themselves to effective regeneration, especially MDF. Those generating MDF-based waste typically pay costs of £100 or more per tonne for its disposal. Effective recovery of MDF fibres can be extremely difficult due to the strong reactive bonds that develop between the thermosetting adhesive and the functional hydroxyl groups of the biomass composite or lignocellulosic fibres. This means that heat alone cannot detach the thermosetting adhesive from the fibres.

[0004] Therefore, there would be great advantage in developing an apparatus and method for effectively separating fibers from biomass composite materials.

[0005] Previous attempts to solve this problem include crude hammer milling techniques, heating of the material (e.g., using microwave radiation or steam heating), or autoclaving. However, these methods have significant drawbacks. For example, crude hammer milling has been found to generate extreme levels of dust. Microwave techniques are too costly in terms of energy, capital, and safety. Steam heating processes typically must be carried out at high temperatures and pressures (e.g., 150°C and 15 bar), thereby having high energy and high equipment costs and complexity, and also run the risk of damaging the fibers in certain processes if moisture expands in and around the composite during the rapid reduction in pressure. Furthermore, the use of autoclaving requires the undesirable addition of chemicals (such as urea) and is not suitable for recovering materials on a large scale due to the batch nature of the process. To ensure a high end use of the recovered fibers, a process that causes the least amount of damage to the fibers in terms of the fiber's length to diameter ratio is desirable. However, prior art processes do not succeed in severing the adhesive from the fibers without causing significant damage.

[0006] EP 2516730 provides a method for regenerating engineered wood materials using ohmic heating. However, EP 2516730 does not describe an efficient method for continuously moving the slurry through the reaction channel. The methods described are effective but potentially inefficient. For example, plug screws and displacement devices are described and work to some extent, but such conveying systems are not optimal after extended use as the slurry containing MDF chips and biomass composites may cause the slurry to clog piping and equipment in the reaction channel after ohmic heating. The slurry can be conveyed more effectively when highly diluted with water, but during operation, the more dilute phase is more expensive to heat.

[0007] It is therefore an object of the present invention to develop improved apparatus and methods that i) are suitable for large-scale continuous processing for effective conveying through reaction channels, ii) can be used to convey slurries of any density, and / or iii) are more energy efficient and economically viable. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] European Patent No. 2516730 Summary of the Invention [Means for solving the problem]

[0009] According to a first aspect of the present invention, there is provided an apparatus for recovering separated fibres from a biomass composite material, comprising: a channel configured to receive a slurry comprising a liquid medium and a biomass composite material; two or more conveyor belts configured to move the slurry through the channel, whereby the biomass composite material is deposited between the two or more conveyor belts; a plurality of electrodes disposed within the channel, the electrodes configured to pass an electric current through the slurry to heat the biomass composite material and achieve separation of the fibers in the biomass composite material; An apparatus is provided comprising:

[0010] According to a second aspect of the present invention, there is provided a method for recovering separated fibers from a biomass composite material, comprising the steps of: providing a slurry comprising a liquid medium and a biomass composite material; moving the slurry through a channel using two or more conveyor belts, wherein the biomass composite material is placed between the two or more conveyor belts; and applying an electric current to the slurry while the biomass composite is between the conveyor belts to heat the biomass composite and achieve separation of the fibers in the biomass composite; and recovering the separated fibers; A method is provided, comprising:

[0011] According to a third aspect, there is provided a method of the second aspect using the apparatus of the first aspect.

[0012] According to a fourth aspect, there are separated fibres so produced according to the methods of the second and third aspects.

[0013] According to a fifth aspect, there is a recycled biomass composite material comprising separated fibers according to the fourth aspect.

[0014] The apparatus and methods described herein can be used to separate and recover fibers from all types of biomass composite materials, including but not limited to fiberboards and particleboards, including MDF.

[0015] Application of electric current to a slurry containing biomass composite and a liquid medium (e.g., water) results in effective ohmic (conductive) heating of the biomass composite compared to other heating methods. Application of ohmic heating results in physical separation between the resin and the fibers and / or breaking of the bonds between the resin(s) and the fibers in the biomass composite. The advantage of applying ohmic heating is the uniform and penetrative heating effect produced by this technique without combustion or charring. This breaks down the resin that binds the biomass fibers together in the biomass composite, resulting in the release and separation of the biomass fibers. This can result in a size expansion of the material (e.g., by about 5 times).

[0016] The present apparatus and method can address the change in the nature of the biomass composite as it moves through the channel from solid pieces of the composite to separated wood fibers. "Separated fibers" in this context indicates that the chemical adhesion between at least some of the fibers has been reduced or completely eliminated such that discontinuous fibers are formed. Separated fibers, while discontinuous, may still form a cohesive and entangled mass of fibers that may be in the form of a sponge-like compressible matrix. Separated fibers may, in some embodiments, be physically separated. The apparatus described herein can address continuous conditions while allowing the reaction to proceed. In particular, the two or more conveyor belts "sandwich" and physically confine the biomass composite, but the belts are flexible enough to allow room for the biomass composite to expand within the channel as liquid medium (e.g., water) is imbibed, and the buoyancy of the material is countered by physically confining the biomass composite (i.e., in a slurry) between the two or more belts. The belts can continuously move the slurry through the channel while applying an electric current to the slurry by applying a voltage to the electrodes. The two or more conveyor belt systems allow for variable conveying speeds and residence times throughout the channel. Additionally, the two or more conveyor belt systems can also efficiently remove separated fibers from the channel.

[0017] The recovered fibers may be of sufficient quality that they can be regenerated / reused into biomass composites, for example, within the fiberboard manufacturing industry and natural fiber insulation. The process itself is repeatable, i.e., the separated and recovered fibers are themselves renewable when used in manufactured products. This offers environmental and economic advantages over other disposal methods, such as landfilling or incineration, with energy recovery (whereby the fibers and (thereby embedded carbon) are "lost" after one cycle). The recycled fibers described herein can be washed in the wet or dry phase and therefore reintroduced into the MDF manufacturing process at one of several points. The recycled fibers described herein can also be sorted or graded. The recycled fibers described herein may be coated with adhesives, such as urea-formaldehyde, melamine, phenolic, MDI or pDI adhesives, or may not be coated with adhesives, for further use.

[0018] The apparatus and methods described herein do not generate large amounts of dust, nor do the methods require the use of dangerous or hazardous chemicals.

[0019] The devices and methods described herein are less energy intensive and more environmentally friendly than other devices and methods in the art, for example, in some instances the liquid medium can be heated and reused in a continuous process.

[0020] The apparatus and methods described herein are suitable for use with slurries of any density. Compared to prior art methods, the present apparatus and methods can be used with slurries having a higher amount of biomass composite material in the slurry without causing blockages or shutting down the apparatus. Unlike prior art systems that use slurries with low solids concentrations and high pumping or processing rates, the present invention is primarily used with slurries having higher solids concentrations and relatively lower processing rates.

[0021] The processing parameters of the methods herein (eg, preheat temperature, applied power or current, or belt speed) can be readily adjusted depending on the desired processing level and / or properties of the input material.

[0022] The method and apparatus are suitable for continuous processing of large volumes of biomass fibers from manufacturing products, which is significantly more advantageous and efficient than batch processing due to the highly targeted application of energy to targeted materials.

[0023] The methods and apparatus described herein are also suitable for separating finished materials (i.e., materials having surface finishes (e.g., veneer, metal foil paint) commonly applied to composite products) from biomass fibers. The methods and apparatus described herein are suitable for processing different waste streams (i.e., finished and unfinished materials or combinations thereof). The apparatus and methods are also suitable for separating biomass composite materials (i.e., MDF waste) from other biomass waste (e.g., conventional wood waste).

[0024] The methods and apparatus described herein are non-abrasive so that high quality fibers are recovered using recycled fibers having the same or similar length as the fibers input to the methods and apparatus. This is therefore an improvement over methods that utilize pressure release (such as autoclaving), pulping, screw conveying, or steam explosion, which can weaken the fibers when subjected to extended residence time in water or any other liquid medium.

[0025] Additionally, the methods and apparatus described herein are capable of processing materials with a high percentage of solid contaminants, such as wood or plastic, without clogging. As a result, the methods and apparatus of the present invention are an improvement over any methods and apparatus that utilize a screw or plug screw conveying system, making them particularly suitable for recycled consumer materials.

[0026] Particular embodiments of the invention may also have one or more of the following advantages.

[0027] In certain embodiments, the distance between the two (or more) conveyor belts is increased along the length of the channel, allowing room for the material to expand further as it progresses along the length of the channel. This can be accomplished by placing increasing separations in the roller positioning or by controlling the applied tension of the belts.

[0028] In certain embodiments, the channel is preferably fully filled with a liquid medium (e.g., water) and the two conveyor belts force the biomass composite material held between the two conveyor belts to be submerged in the liquid medium (e.g., water). This is advantageous because, depending on the density of the biomass composite material, the material may otherwise tend to float.

[0029] In certain embodiments, the use of a non-conductive conveyor belt may be preferred to prevent the current created by applying a voltage to the electrodes from substantially bypassing the slurry.

[0030] In certain embodiments, a mesh material is used for two or more conveyor belts (or at least one of the belts, e.g., the lower belt). This has several advantages:

[0031] o This allows a liquid medium (e.g., water) to pass through the conveyor belt, which can be used to wet the biomass composite and / or replace liquid medium (e.g., water) that is absorbed by the biomass composite.

[0032] o The use of mesh conveyors allows the biomass composite material to be transported and current to be passed through the material in the channel while simultaneously removing contaminating dust and fine particles, which improves the quality of the regenerated fiber.

[0033] o The mesh material allows for placement of electrodes positioned above and below the channel.

[0034] o The mesh materials described herein are preferably constructed from materials that have high tensile strength and can withstand high operating temperatures (e.g., up to 100° C.). PTFE-coated Kevlar mesh has been found to be particularly suitable for constructing meshes due to the material's lightweight, high tensile strength, suitability for use at high temperatures, and resistance to physical abrasion.

[0035] In certain embodiments, an automatic tensioning system is utilized to automatically adjust the tension between two or more conveyor belts to ensure that the slurry and / or biomass composite material is constrained between the two or more conveyor belts. This can be a pneumatic, mechanical, or hydraulic tensioning system.

[0036] In certain embodiments, the apparatus includes at least one baffle on a side of the channel between the two conveyor belts, and preferably two baffles on each of two opposing sides of the channel between the two conveyor belts, which directs the biomass composite and / or slurry away from the edges of the conveyor belts, reducing the chance of the slurry and / or biomass composite spilling over the edges as it expands through the channel.

[0037] In certain embodiments, the presence of an electrolyte (e.g., salt or sodium silicate) in the liquid medium (e.g., water) increases the electrical conductivity of the slurry and / or improves the heating efficiency of the slurry and biomass composite.

[0038] In certain embodiments, electrodes are placed above and below the slurry containing the liquid medium (e.g., water) and the biomass composite, and optionally above and below the conveyor belt, so that current can pass vertically through the slurry. Computational modeling has demonstrated that when the electrodes have this arrangement, increased energy efficiency can be achieved compared to devices with different electrode orientations. In other embodiments, the electrodes are laterally spaced apart from one another, e.g., placed on or adjacent opposing side walls, to allow lateral flow of current through the slurry. Test devices disclosed herein with electrodes placed on the sides of the channel have been demonstrated to efficiently and effectively ohmically heat the biomass composite to achieve fiber separation.

[0039] In certain embodiments, the electrodes are arranged in at least two separate groups or arrays within the channel (i.e., the electrodes in a group or array include two or more electrodes, and the electrodes in a group or array are controlled together so that a current flows between them). This provides greater flexibility in the ohmic heating and power supply of the device. For example, more power can be supplied to a first electrode array in a first portion of the channel compared to a second electrode array in a second portion of the channel. This can be more energy efficient than applying the same power over the entire length of the channel. Alternatively, the non-uniform power distribution can give better results in terms of the speed of processing the material compared to an equal power distribution over the length of the channel.

[0040] · In certain embodiments of the method, the biomass composite is ohmically heated to a temperature between 30-100°C, preferably between 50-100°C, preferably between 75°C-100°C. Ohmic heating promotes separation of the fibers in the biomass composite (e.g., by breaking chemical bonds between the resin and the constituent biomass fibers) and liberates the separated fibers for recovery. In certain embodiments, the biomass composite is preheated before entering the channel. Modeling has demonstrated that preheating the biomass composite before entering the channel can give a more energy-efficient and cost-efficient process while providing a greater degree of control. For example, preheating can be achieved using alternative energy sources such as gas. Additionally, preheating the biomass composite before entering the channel reduces the possibility of the biomass composite causing a "shock" in the system caused by reducing the temperature of the liquid medium (e.g., water) in the channel. This preheating can also be efficiently incorporated into the infeed conveyor.

[0041] In some embodiments, in the method, the biomass composite is pre-shredded and mechanically disintegrated prior to entering the channel to aid in process efficiency.

[0042] In certain embodiments, the biomass composite and / or slurry has a depth of 5-50 cm along the length of the channel between the conveyor belts. Maintaining a stable depth of the biomass composite ensures that the process can be more effectively controlled while still applying a constant amount of electrical current.

[0043] In certain embodiments, the belt speed is up to 100 mm / s, or in the range of 2 mm / s to 50 mm / s. This ensures that the slurry moves continuously through the channels and equipment while ensuring that the slurry and biomass composite has sufficient residence time in the channels and equipment for heating to achieve separation of the biomass fibers. The belt speed and residence time can be easily varied depending on the level of processing required.

[0044] In certain embodiments, the apparatus further comprises a deagglomeration module or agitation vessel downstream of the outlet of the channel, which can be used to loosen and release fibers from any remaining tightly bound lumps or clumps of the biomass composite by a beating type action or mixing / agitation.

[0045] In some embodiments, the operating level of liquid medium (e.g., water) in the channel is maintained by an automated system that continuously adds more liquid medium to the channel as it is absorbed or replaced.

[0046] In certain embodiments, the biomass composite is an engineered wood material, such as MDF or HDF. This is advantageous because certain fiberboards, including MDF, are otherwise difficult to recover and regenerate.

[0047] In certain embodiments, the invention allows for subsequent processing steps to dry the fibers to various degrees, providing flexibility and control of the moisture content of the separated and recovered fibers, thereby providing multiple entry points into a biomass composite (e.g. fiber board) manufacturing process line that can vary between processing plants.

[0048] In certain embodiments, the apparatus disclosed herein can affect the dewatering or removal of the liquid medium downstream of the channel, for example, by extending the belt so that it extends downstream of the channel, by using certain materials (e.g., mesh materials) of the belt, and optionally by using an elevation angle. This can reduce the energy load associated with the subsequent drying or dewatering process. Furthermore, the dewatering or liquid removal process can also allow the heated liquid medium (e.g., water) to be retained within the channel, since the removed liquid medium can be recirculated back into the channel.

[0049] In a further embodiment, the process can remove adhesive binders from feedstocks that include synthetic fibers, mineral fibers, or composite mixtures of synthetic or mineral fibers and lignocellulosic fibers.

[0050] In further embodiments, the described processes can extract proteins and carbohydrates from biomass, acting as a pretreatment step prior to enzymatic digestion, fermentation or other biorefining processes.

[0051] Non-limiting and non-exhaustive embodiments of the present invention will now be described with reference to the following figures. [Brief description of the drawings]

[0052] [Figure 1] 1 illustrates an exemplary device according to the present invention. [Diagram 2] 1 illustrates an exemplary process according to the present invention. [Diagram 3] The results of computational modeling of the heating efficiency of various arrangements of electrodes are shown: top) a vertical arrangement of electrodes where the electrodes are placed on the sides of the channel, or bottom) a horizontal arrangement of electrodes where the electrodes are placed on the top and bottom of the channel. Each graph shows a cross section along the length of the device, with material starting on the left and conveyed to the right. The grey area represents the liquid medium and the black area represents the slurry (biomass composite and liquid medium) between the conveyors. As can be observed, the horizontal arrangement shown by the bottom graph results in a more rapidly progressing expansion of the slurry at the front of the device, and a higher overall expansion achieved by the ends of the device. This is achieved with a lower power input for a comparable amount of material processed, and is therefore more cost-effective. [Figure 4] 1 shows exemplary photographs of A) biomass composite material in the form of MDF before entering the device and before applying the method of the invention, and B) separated fibers after exiting the device and after applying the method of the invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0053] Aspects of the invention have been described above. Optional and preferred features are described below. Unless otherwise specified, any optional or preferred feature can be combined with any other optional or preferred feature and aspect or embodiment of the invention mentioned herein, unless the context dictates otherwise. For example, throughout this specification, the use of the phrases "examples," "exemplary embodiments," "some embodiments," "embodiments," "preferred embodiments," or other similar language refers to the fact that a particular feature, structure, or attribute described in connection with an embodiment may be included in at least one embodiment of the invention. Thus, throughout this specification, the appearance of the phrases "in an embodiment," "exemplary embodiments," "some embodiments," "in other embodiments," or other similar language does not necessarily all refer to the same group of embodiments, and the described features, structures, or attributes may be combined in any suitable manner in one or more embodiments.

[0054] All measurements herein are measured under standard conditions unless otherwise specified. All averages referred to herein refer to averages unless otherwise specified.

[0055] When a standard test is referred to herein, unless otherwise specified, the version of the test referred to is the most current at the time of filing this patent application.

[0056] It will be readily understood that the features of the apparatus and methods as generally described and illustrated in the Figures could be arranged and designed in a wide variety of different configurations. Thus, the descriptions of the present apparatus and method embodiments are not intended to limit the scope of the invention as claimed, but are merely representative of selected embodiments or examples of the invention.

[0057] As used in this specification and the appended claims, the singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise.

[0058] As used herein, the term "about" is used to provide flexibility to the endpoints of a numerical range by providing that a given value may be slightly above or below the endpoint. The degree of flexibility of this term can be determined depending on the particular variable and is within the knowledge of one of ordinary skill in the art to determine based on experience and the relevant explanations herein.

[0059] As used herein, the term "comprises" has an open meaning that allows for other unspecified features to be present. This term encompasses, but is not limited to, the semi-closed term "consisting essentially of" and the closed term "consisting of." Unless the context indicates otherwise, the term "comprises" may be replaced with either "consisting essentially of" or "consists of."

[0060] As described herein, the term "slurry" refers to a mixture of a liquid medium (e.g., water) and a biomass composite. The term encompasses wet biomass composites and biomass composites suspended or held in a liquid medium, preferably water. In some embodiments, the liquid medium is a non-aqueous material, such as an alcohol, ether, ketone, alkyl or aromatic solvent. In other embodiments, the medium is an ionic liquid. An example of a suitable ionic liquid is BMIM-PF6 (1-butyl-3-methylimidazolium hexafluorophosphate).

[0061] As used herein, a "biomass composite" refers to a plant or animal material constructed by artificially binding plant or animal fibers together, for example, using an adhesive, glue, or resin matrix. In some embodiments, a biomass composite is any composite formed from or including plant fibers. In some embodiments, a biomass composite is any composite formed from or including lignocellulosic fibers. In some embodiments, a biomass composite is any material that includes lignin and one or more of an adhesive, binder, resin, or glue. In some embodiments, a biomass composite is a wood composite. In some embodiments, the material may be derived from, but is not limited to, wood, bamboo, palm, vegetables, straw (e.g., lime straw, wheat straw, rice straw), stalks (e.g., hemp stalk, kenaf stalk), sugarcane residue, coir, coconut shell fiber, or any combination thereof. An example of a biomass composite is an engineered wood material.

[0062] As used herein, "engineered wood material" refers to materials such as fiberboards and particleboards that are constructed by artificially bonding wood fibers using, for example, adhesives, binder glues, or resin matrices. Engineered wood materials can alternatively refer to or include wood composites, wood-plastic composites, or manufactured boards. Examples of engineered wood materials include medium density fiberboard (MDF), high density fiberboard (HDF), and particleboard.

[0063] As described herein, fiberboard may refer to a processed product formed by breaking down lignocellulosic material (e.g., wood) into fibers (often with a defibrillator), combining the fibers with resin, and subjecting them to high temperature and / or pressure.

[0064] As described herein, MDF is a medium density fiberboard having a density of, for example, 400 to 900 kg / m 3 This refers to a medium density fiberboard, which is a fiberboard having a fiber density of 1000 mm or more.

[0065] As used herein, HDF refers to high density fiberboard having a higher density of fibers compared to medium density fiberboard, typically 900 kg / m 3 Refers to fiberboard with a greater fiber density.

[0066] As described herein, softboard has a strength of 400 kg / m 3 This refers to a low density fiberboard having a fiber density of less than 100 mm.

[0067] As described herein, particleboard can refer to an engineered product made from lignocellulosic materials (e.g., wood chips) and synthetic resins (or other suitable binders) that are pressed and extruded.

[0068] As described herein, a "fibrous insulation board" has a fiber insulation strength of 200 kg / m 3 (e.g. for rigid boards) or less than 80 kg / m 3 It refers to a low density fiber board having a fiber density of less than 100 mm (e.g., for flexible boards). This fiber board is designed to provide thermal insulation and sound insulation in the construction industry. The terms rigid and flexible are terms commonly used in the construction industry to indicate the degree of structural strength of the product and therefore the typical application area within a building. In some embodiments, the fiber insulation board is flexible or rigid. In a preferred embodiment, the fiber insulation board comprises wood fibers and is a wood fiber insulation board. In other embodiments, the fiber insulation board comprises non-wood fibers (e.g., any other composite formed from resin and lignocellulosic fibers).

[0069] As described herein, the term "achieving fiber separation" refers to the separation of fibers within a biomass composite mass of fibrous material or individual fibers. In some embodiments, fiber separation is caused at least in part by the detachment and / or breaking of chemical bonds between the resin and the fibers of the biomass composite during heating. In some embodiments, fiber separation is caused at least in part by the decomposition of the resin in the biomass composite that would otherwise hold the fibers together.

[0070] The slurries described herein include a biomass composite material and a liquid medium, preferably water. In some embodiments, the slurries consist of a biomass composite material and a liquid medium, preferably water. In other embodiments, the slurries further include other materials, such as conventional wood materials. The other materials, such as conventional wood, are contaminants in the process.

[0071] In the apparatus and methods described herein, the slurry is transported through a channel and an electric current passes through the slurry as it is transported along the channel. The slurry may be formed within the channel (i.e., by mixing the biomass composite with a liquid medium (e.g., water) within the channel) or the slurry may be formed prior to entering the channel (i.e., by mixing the biomass composite with a liquid medium (e.g., water) in a wetting module upstream of the channel).

[0072] In some embodiments, the slurry and / or biomass composite in the channel has an average material depth between the two conveyor belts of between 5 cm and 50 cm, more preferably between 10 cm and 50 cm. In some embodiments, the depth of the slurry and / or biomass composite varies by ±25%, or ±10%, or ±5% along the entire length and width of the conveyor belt. Maintaining a stable and uniform depth of the biomass composite between the two conveyors in the channel ensures that the process can be more effectively controlled while applying a constant amount of current.

[0073] The slurry preferably contains a high density biomass composite. In some embodiments, the slurry contains a porosity (i.e., amount of space between biomass composites) of less than 50%, preferably less than 45%, preferably less than 40%, preferably less than 35%, preferably less than 30%, or preferably 25% or less (e.g., at the inlet of the channel). In some embodiments, the porosity is between 20% and 50%, more preferably between 20% and 35%. In some embodiments, the slurry contains a liquid medium (e.g., water) and biomass composite in a ratio of 8:1 to 1:1, or 8.1 to 2.5:1, or 7:1 to 1.5:1, or 6:1 to 1.5:1, or 4:1 to 2:1 by weight. In some embodiments, the slurry contains a liquid medium (e.g., water) and biomass composite in a ratio of up to 7:1, or up to 6:1, or up to 5:1, or up to 4:1, or up to 3:1 by weight (e.g., at the inlet of the channel). In some examples, for every 1 kg of dry composite biomass material fed into the channel, the slurry at the inlet to the channel contains about 4 kg of liquid medium (eg, water).

[0074] In the channels, the liquid medium (e.g., water or brine) is partially absorbed into the biomass fibers and / or fills the voids between the pieces of biomass composite. For best results, it is desirable to keep the dense bed of biomass composite placed between the two conveyor belts submerged with the liquid medium (e.g., water). If the biomass composite (e.g., MDF) is too diluted, it becomes difficult to maintain the heating of the composite, but if the biomass composite (e.g., MDF) is not wet enough, its electrical conductivity is reduced.

[0075] Biomass Composites In some embodiments, the biomass composite is an engineered wood material (e.g., wood composite), and the biomass fibers are wood fibers. The wood fibers may be aggregated in the form of particles, such as particles in chipboard or low-density fiberboard. In some embodiments, the biomass composite is a particle board, fiber board, or fiber insulation board (e.g., any lignocellulosic fiber insulation board, such as wood fiber insulation board). In some embodiments, the biomass composite is a fiber board or particle board. In some embodiments, the biomass composite is a soft board, a medium density fiber board (MDF), a high density fiber board (HDF), or a particle board (i.e., otherwise known as chipboard or low density fiber board). In some examples, the MDF is an ultra-lightweight MDF plate (ULDF), a moisture-resistant board, or a fire-retardant MDF, or a combination thereof. In some embodiments, the biomass composite is a fiber insulation board, more preferably a wood fiber insulation board, and the fiber insulation board can be flexible or rigid. In other embodiments, the fiber insulation board may be a non-wood fiber insulation board (eg, any other composite formed from resin and lignocellulosic fibers).

[0076] In some embodiments, the biomass composite includes particleboard or fiberboard in combination with non-composite materials (i.e., traditional wood materials). In some embodiments, the biomass composite is a finished biomass composite (i.e., includes a facing or veneer), or an unfinished biomass composite (i.e., does not include a facing or veneer). In some embodiments, the biomass composite further includes one or more of plywood, oriented strand board (i.e., otherwise known as flakeboard, waferboard, or chipboard), or any combination thereof. These other materials are typically contaminants during the process.

[0077] In some embodiments, the biomass composite is chopped before being introduced between the conveyor belts as part of the slurry. The biomass composite may be chopped in a dry form, i.e., before being combined with a liquid medium to form a slurry, or as part of the slurry. In some examples, before being introduced between the conveyor belts as part of the slurry, at least a portion of the biomass composite is in the form of pieces, which may be layered pieces. A layered piece is a piece having a first and second dimension of length greater than a third dimension, each of the first, second and third dimensions being perpendicular to each other. In other words, the layered piece is a platelet-like piece. In some examples, before being introduced between the conveyor belts as part of the slurry, the chopped biomass composite comprises pieces, which may be layered, at least a portion of which (preferably at least 25% (by number), optionally at least 50% (by number), optionally at least 75% (by number)) have a length of 10 to 45 mm, preferably 30 to 40 mm, when measured along its longest dimension. In some examples, prior to being introduced between the conveyor belts as part of the slurry, the chopped biomass composite comprises pieces which may be layered, at least a portion of which (preferably at least 25% (by number), optionally at least 50% (by number)) have a thickness of 3 to 10 mm, as measured along the shortest dimension of the pieces, prior to being introduced between the conveyor belts as part of the slurry. In some examples, the biomass composite may be chopped in a chopping step using a mechanical disruption module forming part of the apparatus described herein.

[0078] In some embodiments, the biomass composite has any suitable dry density (i.e., density prior to mixing with a wet or liquid medium (e.g., water) to form a slurry). In one embodiment, the biomass composite has a dry density of 100 to 1100 kg / m 3 , or 200-900kg / m 3 , preferably 450 to 900 kg / m3 In some embodiments, the biomass composite has a dry density of 100 kg / m 3 Greater than or equal to 200kg / m 3 Greater than or equal to 300kg / m 3 Greater than or equal to 400kg / m 3 Greater than or equal to 500kg / m 3 Greater than or equal to 600kg / m 3 Greater than or equal to 700kg / m 3 Greater than or equal to 800kg / m 3 Greater than or equal to 900kg / m 3 or greater than 1000kg / m 3 In some embodiments, the dry density of the biomass composite material is greater than 1100 kg / m 3 Less than or equal to 1000kg / m 3 Less than or equal to 900kg / m 3 Less than or equal to 800 kg / m 3 Less than or equal to 700 kg / m 3 Less than or equal to 600 kg / m 3 Less than or equal to 500 kg / m 3 Less than or equal to 400 kg / m 3 Less than or equal to 300 kg / m 3 Less than or equal to 200 kg / m 3 is less than.

[0079] In some embodiments, the biomass composite material comprises 70-90% by weight of biomass fiber (e.g., wood fiber) and 5-20% by weight of resin. In some embodiments, the biomass composite material comprises 75%-87.5% by weight of biomass fiber (e.g., wood fiber) and 5-15% by weight of resin, or 80%-85% by weight of biomass fiber (e.g., wood fiber) and 7%-12.5% ​​by weight of resin. In some embodiments, the biomass composite material further comprises wax (e.g., in an amount of less than 2% by weight) and / or silicon (e.g., in an amount of less than 0.05% by weight). As used herein, the term "resin" may be used interchangeably with glue, adhesive, or binder. In some examples, the resin is urea-formaldehyde (UF), melamine-urea-formaldehyde (MUF), methylene diisocyanate (MDI), polymeric methylene diisocyanate (PMDI), phenol-formaldehyde (PF), or any combination thereof. In some embodiments, the resin may be a bioadhesive. A bioadhesive as described herein may refer to an adhesive substance produced or obtained by a living organism. A bioadhesive may include or be selected from biological monomers, including, but not limited to, sugars, proteins, and carbohydrates.

[0080] liquid medium The slurry includes a liquid medium. The liquid medium is preferably a conductive liquid medium. In some embodiments, the liquid medium has a conductivity of greater than 1 mS / m, or greater than 10 mS / m, or greater than 100 mS / m, or greater than 200 mS / m, or greater than 300 mS / m, or greater than 400 mS / m, or greater than 500 mS / m, or greater than 600 mS / m. In some embodiments, the liquid medium has a conductivity of 100 mS / m to 1500 mS / m, or 200 mS / m to 1000 mS / m, or 300 mS / m to 900 mS / m, or 400 mS / m to 800 mS / m, or 500 mS / m to 700 mS / m. In some examples, the liquid medium is a brine, which may have a conductivity within any of the ranges described above, and in some embodiments, a conductivity of 600 mS / m. The conductivity can be selected with respect to the device dimensions and required processing speed so that an appropriate and economical electrical design can be achieved to deliver the required power. In the device configuration described herein, a conductivity of about 600 mS / m allows the use of commercially available electric drive systems utilizing non-specialized components and connection to common distribution voltages.

[0081] In a preferred embodiment, the liquid medium is water. In some embodiments, no additives are added to the water. In other embodiments, the water includes an electrolyte (i.e., a salt or molecule that ionizes in water). In some embodiments, the electrolyte includes one or more of sodium, chloride, magnesium, phosphate, sulfate, or calcium. In some embodiments, the electrolyte is sodium chloride, i.e., the water is a brine. The use of brine (or any other electrolyte) improves the conductivity of the water and improves heating efficiency. In some embodiments, the electrolyte includes sodium silicate, which may provide fire-resistant properties to the fibers.

[0082] In a preferred embodiment, the liquid medium (e.g., water) is free or substantially free of chemicals or chemical additives (apart from the biomass composite, the liquid and any electrolytes). This may include chemicals that may be harmful to the environment and / or humans, or that may adversely affect the subsequent use of the recovered fibers, such as substances that may be harmful to the manufacturing or performance characteristics of new MDF boards.

[0083] channel The channel refers to the portion of the apparatus where the slurry and / or biomass composite is treated with the electrodes to heat the biomass composite and / or slurry (i.e., ohmic heating). The channel may otherwise be referred to as a reaction channel, processing area, or ohmic heater. In the present invention, the slurry is moved through the channel using two or more conveyor belts, and multiple electrodes are placed within the channel.

[0084] The channels are sized to provide sufficient residence time for the slurry and / or biomass composite within the channel and / or to ensure the distance between the electrodes (i.e., if the electrodes are located above and below the channel or on the sides of the channel) to operate at suitable voltages with commonly available equipment. In some examples, the channels are 2 to 50 meters long (preferably 5 to 25 meters long), 0.2 to 5 meters wide, and / or 0.1 to 1 meter deep.

[0085] In some embodiments, the device includes multiple channels, for example two or more channels, which may be preferable when scaling up the device.

[0086] In some embodiments, the channel may include a preheating region and an electrode region, the preheating region being upstream of the electrode region. In the preheating section, the biomass composite is preheated by a suitable technique (e.g., a technique selected from hot water, which may be in liquid or vapor form, and radiative heating methods, such as using lamps, e.g., halogen lamps, to a temperature of, for example, about 50°C to up to 100°C, or 60°C to about 100°C, or 65°C to about 100°C, or 70°C to about 100°C, or 75°C to about 100°C, or 80°C to about 100°C) The electrode region includes multiple electrodes within the channel. In some embodiments, the channel may include only the electrode region (i.e., the preheating module is instead located upstream of the channel). Preheating can result in process improvements, including shorter residence times in ohmic heating and / or lower power input in ohmic heating.

[0087] In preferred embodiments, the channel is not pressurized, i.e., the channel is at atmospheric pressure. Nevertheless, in some embodiments, the channel may be pressurized, i.e., up to 20 times atmospheric pressure (20 barg).

[0088] In use, the channel contains a slurry including a liquid medium (e.g., water) and a biomass composite material. The liquid medium (e.g., water) is present in the channel such that a conductive path is available between the electrodes. In some embodiments, the liquid medium is present in the channel such that at least 70%, or at least 75%, or at least 80%, or at least 85%, or at least 90%, or at least 95%, or at least 99% of the volume of the channel is filled with water, or the channel is completely filled with water. In some embodiments, the device includes an automatic top-up system (i.e., replaces water lost from the device). The operating level of the water is preferably above the upper belt of the two conveyor belt system.

[0089] The channel may be formed from any suitable material. The channel is preferably formed from a non-conductive material, for example a polymeric material such as polyalkylene. The material is selected so that it can withstand the operating temperatures of the method. In some embodiments, the channel is formed from a material that is heat resistant to a temperature of at least 100°C, or at least 120°C, or at least 150°C, or at least 175°C, or at least 200°C, or at least 225°C, or at least 250°C. In some examples, the channel is formed from polypropylene.

[0090] The channel may have any suitable shape. In some embodiments, the channel is rectangular. In alternative embodiments, the channel is shaped to mimic or accommodate the profile of two or more conveyor belts (e.g., the expansion profile of two or more conveyor belts). In some embodiments, the channel is shaped to have a top or bottom that slopes from an entry point to an exit point (i.e., matches the profile of the sloped conveyor belt). In a preferred embodiment, the channel is shaped to have a bottom that slopes from an entry point to an exit point (i.e., matches the profile of the sloped lower conveyor belt).

[0091] This can allow for lower energy usage, as less liquid medium (e.g., water) is needed to fill the channel, as opposed to rectangular channels. Furthermore, the slope of the bottom can prevent the formation of stagnant areas of the liquid medium in the device and can prevent solid particles from settling to the bottom of the channel. This can be advantageous from a maintenance perspective and ensures maximum recovery of fibers.

[0092] Conveyor Belt The apparatus described herein comprises two or more conveyor belts. The point where the two or more conveyor belts feed into the channel is the entry point, and the point where the two or more conveyor belts feed out of the channel is the exit point. The two or more conveyor belts, preferably a lower conveyor belt and an upper conveyor belt, are disposed on top of each other in the channel with a space between the two conveyor belts (i.e., for the presence of the biomass composite material and slurry).

[0093] In use, the slurry and biomass composite material are placed between two or more conveyor belts in the channel, e.g., in a sandwich arrangement, such that the slurry and biomass composite material are physically trapped. The two or more conveyor belts are configured to move the slurry through the channel by any suitable means. In some embodiments, the two or more conveyor belts are moved by rollers. In some embodiments, the rollers comprise driven rollers (e.g., one per belt) and one or more guide rollers.

[0094] In a preferred embodiment, the biomass composite material is fed into the channel via a lower belt.

[0095] The conveyor belts are configured to move at any suitable speed. The speed can vary depending on the desired residence time of the slurry in the channel or reactor. In some embodiments, the belt speed of the two or more conveyor belts is up to 100 mm / s. In some embodiments, the belt speed of the two or more conveyor belts is from about 1 mm / s to about 75 mm / s, or from about 2 mm / s to about 50 mm / s, or from about 2.5 mm / s to about 20 mm / s, or from about 3 mm / s to about 15 mm / s, or from about 3.5 mm / s to about 12.5 mm / s, or from about 4 mm / s to about 10 mm / s, or from about 5 mm / s to about 9 mm / s. In some embodiments, the belt speed is greater than 1 mm / s, or greater than 2 mm / s, or greater than 3 mm / s, or greater than 4 mm / s, or greater than 5 mm / s, or greater than 6 mm / s, or greater than 7 mm / s, or greater than 8 mm / s, or greater than 9 mm / s, or greater than 10 mm / s, or greater than 15 mm / s, or greater than 20 mm / s. In some embodiments, the belt speed is less than 25 mm / s, or less than 20 mm / s, or less than 17.5 mm / s, or less than 15 mm / s, or less than 12.5 mm / s, or less than 10 mm / s, or less than 9 mm / s. Nevertheless, the belt speed can be adjusted to account for different properties (e.g., density) of the biomass composite material, which can change the selected residence time.

[0096] The two or more conveyor belts may include a lower belt and an upper belt and may be formed of any suitable material. In some embodiments, the two or more conveyor belts, e.g., the lower belt and the upper belt, are made of the same material as one another. In other embodiments, the two or more conveyor belts, e.g., the lower belt and the upper belt, are made of different materials.

[0097] In some embodiments, the two or more conveyor belts (e.g., the lower belt and / or the upper belt) are preferably made of non-conductive material. The use of non-conductive belts is safer in the operation and construction of the device and minimizes the risk of electrical potentials being present outside the channel. Furthermore, the inventors have found that non-conductive belts are advantageous because the current density and power dissipation in the process material are independent of the spacing between the two belts.

[0098] In an alternative embodiment, the two or more conveyor belts can be made of a conductive material, which can provide advantages in providing an electrical potential directly to the slurry material. Non-conductive refers to a material that has a lower electrical conductivity than water, e.g., tap water, e.g., a conductivity of 0.05 S / m or less, preferably 0.005 S / m or less, preferably 0.0005 S / m or less.

[0099] The two or more conveyor belts are preferably strong enough to withstand the forces occurring in the apparatus. In some embodiments, the two or more conveyor belts (i.e., the lower belt and / or the upper belt) are formed of a material with high tensile strength. In some embodiments, the two or more conveyor belts are formed of a material with a tensile strength of more than 2000N / 5cm, or more than 2500N / 5cm, or more than 3000N / 5cm, or more than 3500N / 5cm, or more than 4000N / 5cm, or more than 4500N / 5cm, or more than 5000N / 5cm, or more than 5500N / 5cm. In some embodiments, the two or more conveyor belts are formed of a material with a tensile strength of 2500N / 5cm to 12500N / 5cm, or 3000 to 8000N / 5cm.

[0100] The two or more conveyor belts are preferably sufficiently heat resistant to withstand the temperatures within the channel, in some embodiments, the two or more conveyor belts are heat resistant to temperatures of at least 100°C, or at least 120°C, or at least 150°C, or at least 175°C, or at least 200°C, or at least 225°C, or at least 250°C.

[0101] In some embodiments, the two or more conveyor belts (i.e., the lower belt and / or the upper belt) comprise a material selected from a polymeric material and a ceramic material. In some embodiments, the two or more conveyor belts (i.e., the lower belt and / or the upper belt) comprise a material selected from an aramid, PTFE (i.e., polytetrafluoroethylene), fiberglass, polyester, PBO (polybenzobisoxazole), rubber, polyurethane, nylon, nitrile, neoprene, polyester, polyolefin, such as polyethylene or polypropylene. The aramid may be a para-aramid (e.g., poly(azanediyl-1,4-phenyleneazanediylterephthaloyl), sometimes commercially referred to as Kevlar®, available from DuPont) or a meta-aramid (e.g., a polymer formed from the monomers m-phenylenediamine and isophthaloyl chloride, sometimes commercially referred to as Nomex®, available from DuPont). In some embodiments, the two or more conveyor belts are formed of a coated para-aramid material, more particularly a PTFE coated para-aramid material, such conveyor belts having high tensile strength and capable of withstanding high temperatures.

[0102] At least one of the two or more conveyor belts (i.e., the lower belt and / or the upper belt) is preferably made of a mesh material, more preferably a non-conductive mesh material. A mesh material is described as any material that includes holes or openings. This allows a path for a liquid medium (e.g., water) to travel through the conveyor belt, for example to wet the biomass composite material or to replace the liquid medium (e.g., water) absorbed by the biomass composite material. The mesh material is also compatible with various electrode configurations, i.e., configurations having electrodes installed above and below the conveyor belt, so that an electric current can pass through the conveyor belt. The use of a mesh can also allow for the simultaneous removal or separation of dust or fine particles from the separated fibers.

[0103] The mesh may have any suitable size of openings, but is preferably small enough to retain the separated fibers on the conveyor belt(s). In some embodiments, the mesh may have an opening size of about 1-20 mm, more preferably 1-6 mm, and even more preferably 1-3 mm, with the opening size being defined as the size of the diameter or longest dimension. In some embodiments, the mesh may have an opening size of less than 6 mm, or less than 5 mm, or less than 4 mm, or less than 3 mm, or less than 2 mm. In some embodiments, the open mesh may have a mesh size of greater than 1 mm, or greater than 2 mm, or greater than 3 mm, or greater than 4 mm, or greater than 5 mm.

[0104] The mesh can have apertures of any suitable shape. In some embodiments, the ratio of the longest dimension of the aperture to the shortest dimension of the aperture is preferably less than 2:1, or less than 1.5:1. In some examples, the apertures are circular or square.

[0105] In some embodiments, the distance between the two or more conveyor belts is adaptable along the length of the channel. In some embodiments, the distance between the two or more conveyor belts (i.e., the lower belt and the upper belt) increases along the length of the channel (i.e., from the entry point to the exit point). In other words, the two or more conveyor belts diverge and / or separate as they progress along the length of the channel (i.e., from the entry point to the exit point), e.g., at least one of the two or more conveyor belts is inclined along the length of the channel. As a result, the distance between the two conveyor belts at the entry point of the channel is less than the distance between the two conveyor belts at the exit point of the channel. In some embodiments, the distance between the two conveyor belts increases by at least 20% over the length of the channel (i.e., from the entry point to the exit point), preferably, the distance between the two conveyor belts increases by 20-400% over the length of the channel. In some embodiments, the distance between the two conveyor belts at the entry point of the channel is 25-300 mm, or 100-275 mm, or 150-250 mm (e.g., 200 mm), and the distance between the two conveyor belts at the exit point of the channel is 50-600 mm, or 200-450 mm, or 250 mm-400 mm, or 300-350 mm. The separation of the two conveyor belts along the length of the channel allows for expansion of the slurry as the reaction proceeds (i.e., the slurry is ohmically heated and the resin is decomposed). In some embodiments, the distance between the two conveyor belts is increased or adapted by changing the roller positioning. In other embodiments, the distance between the two conveyor belts is increased or adapted by controlling the applied tension of the belts. In some embodiments, the apparatus further comprises an automatic tensioning system for adjusting the tension between the two or more conveyor belts. In some embodiments, the distance between the two or more conveyor belts remains substantially similar along the length of the channel. In some embodiments, the automatic tensioning system is a pneumatic tensioning system, a mechanical tensioning system, an electrical tensioning system, or a hydraulic tensioning system.

[0106] The distance between the entry points of the two or more conveyor belts in the channel and the exit points of the two conveyor belts may be any suitable distance (varies depending on the scale of the apparatus and the size of the channel). In some examples, the distance is between 1 and 20 meters, optionally between 5 and 20 meters.

[0107] The two conveyors or belts can have any suitable width (depending on the scale of the equipment and the size of the channel). In some embodiments, the width of the belt is up to 5 meters, or about 0.1 meters to about 5 meters, or about 0.25 meters to 4 meters. Or about 2 meters to about 4 meters, or about 3 meters. In some embodiments, the width of the belt is greater than 1 meter, or greater than 2 meters, or 3 meters or more, or 4 meters or more.

[0108] The two conveyors or belts may have any suitable thickness. In one embodiment, the two conveyor belts each independently have a thickness of 0.5 mm to 5 mm, or 0.5 mm to 2 mm. The thickness of the belts may be selected depending on the desired tensile strength.

[0109] In some embodiments, the belt includes flights or stiffeners to make the belt more rigid. This can be useful as the size of the apparatus and belt increases. Additionally, the flights can also aid in processing by helping the biomass composite material move through the channel and can eliminate slippage, thereby allowing the two conveyor belts to move while leaving the material behind. Additionally or alternatively, in some embodiments, the apparatus may include rollers to support the belt.

[0110] In some embodiments, two or more conveyor belts lift the separated fibers from the channel for delivery to the next processing step (eg, a drying module, a deagglomeration module, and / or a washing module).

[0111] In some embodiments, the two or more conveyor belts are formed from a mesh material and further comprise an elongated section downstream of the channel to allow water to be drained from the separated fibers. In some embodiments, the elongated section is elevated. In some embodiments, the apparatus further comprises a compression means, e.g. a mechanical press, arranged to compress the elongated section to effect the drainage of water. This may be beneficial since at the outlet of the channel, the separated fibers may contain a high proportion of water, e.g. up to six times the mass of the separated fibers. A further advantage of this water drainage process is that dissolved contaminants can be removed instead of proceeding to a subsequent processing step. In some embodiments, the apparatus comprises a means for returning the drained water to the channel (e.g. by a water circulation unit as disclosed herein). This may be beneficial to return electrolytes and heat to the channel.

[0112] In one embodiment, the apparatus may include a belt washing system. The belt washing system may remove the biomass and / or any other materials from the belt after the biomass has been ohmically heated. The belt washing system may be located toward the opposite end of the channel from where the biomass is introduced into the channel. The belt washing system may act to improve fiber recovery when using the apparatus.

[0113] electrode The apparatus includes a plurality of electrodes disposed within the channel, the electrodes being positioned at any suitable location within the channel such that the electrodes are configured to pass an electrical current through the slurry and the biomass composite material to heat the biomass composite material (i.e., ohmic heating).

[0114] A plurality of electrodes as described herein includes any suitable number of electrodes. In some embodiments, a plurality of electrodes may include at least 2 electrodes, or at least 4 electrodes, or at least 6 electrodes, or at least 8 electrodes, or at least 10 electrodes, or at least 20 electrodes, or at least 30 electrodes.

[0115] In some embodiments (e.g., in non-pressurized systems), the electrodes are configured to heat the slurry and / or maintain the temperature of the slurry at a temperature of 50°C to 100°C, or 60°C to 100°C, or 65°C to 100°C, or 70°C to 100°C, or 75°C to 100°C, or 80°C to 100°C. In some embodiments, the electrodes are configured to heat and / or maintain the temperature of the slurry at a temperature of at least 50°C, or at least 60°C, or at least 65°C, or at least 70°C, or at least 75°C, or at least 80°C. Higher temperatures may facilitate the breakdown of bonds between the resin and the constituent fibers in the biomass composite and / or facilitate the breakdown of resin present in the biomass composite. In some embodiments (e.g., in pressurized systems), the electrodes are configured to heat the slurry and / or maintain the temperature of the slurry at a temperature of up to 200°C.

[0116] In some embodiments, the electrodes are arranged such that the first electrode is spaced from the second electrode to allow the slurry to pass between the first and second electrodes and the current to pass between the first and second electrodes, and in use the first and second electrodes are located at different vertical heights within the channel and / or the first electrode is laterally spaced within the channel from the second electrode. The plurality of first electrodes may be provided, for example, in the form of an array. The plurality of second electrodes may be provided, for example, in the form of an array.

[0117] In some embodiments, the first and second electrodes are placed at different vertical heights (e.g., above and below the slurry). In embodiments where the first and second electrodes are placed at different vertical heights such that the current passes substantially vertically, this has been found to have efficiency advantages over embodiments where they are spaced laterally (i.e., along the horizontal direction). In some embodiments, the electrodes are placed above and below two or more conveyor belts (i.e., in the case of a horizontal conveyor), i.e., the conveyor belts are placed between the first and second electrodes, allowing the current to pass through the conveyor belts and through the slurry between them. In the above-mentioned embodiments, the first and second electrodes may be a single phase and neutral electrical supply, or may be two phases of a multi-phase power supply. The electrodes may further include further electrodes or electrode arrays, for example third and fourth electrodes (or third and fourth electrode arrays), allowing connection to a three-phase or three-phase and neutral electrical supply found in a typical industrial environment, or indeed any number of electrodes and phases as may be conceived for an electrical supply.

[0118] For the electrode arrangements described above, the two or more conveyor belts are of a material suitable for allowing electrical current to pass through the conveyor belts (e.g., conductive material or open mesh conveyors). Modeling suggests that increased energy efficiency is observed when the electrodes are positioned in this manner. The electrodes are preferably positioned outside at least the two or more conveyors at the smallest practical distance from the slurry and / or biomass composite material being processed. In such embodiments, the vertical distance between the first and second electrodes placed at different vertical heights is about 0.1 to 1 meter. In preferred embodiments, the electrodes span at least 70%, or at least 75%, or at least 80%, or about 85%, or about 90%, or about 95%, or about 99% of the width of the two or more conveyor belts, or the electrodes span 100% of the width of the two or more conveyor belts. This allows the material being processed to receive uniform heat input while simultaneously allowing the slurry to be transported through the channel.

[0119] In alternative embodiments, the electrodes or electrode arrays (e.g., first and second electrodes or arrays) are placed, for example, laterally on opposing side walls of the channel, i.e., with the first electrode(s) on a side wall and the second electrode(s) on an opposing side wall, allowing the slurry to pass between them and current to pass through the slurry. As demonstrated in the exemplary methods, electrodes placed on either side of the channel in the device can be used to effectively heat a slurry containing biomass composite material and water to effectively separate and recover fibers from the material. In such embodiments, the distance between the electrodes on either side of the channel can be from about 0.3 to about 5 meters.

[0120] In preferred embodiments, the electrodes span at least 70%, or at least 75%, or at least 80%, or about 85%, or about 90%, or about 95%, or about 99%, or the electrodes span 100% of the distance between the two or more conveyor belts, allowing the material being processed to receive similar heat input while the slurry is being transported through the channel.

[0121] In some embodiments, the first and second electrodes are positioned at different vertical heights within the channel, and the first electrode is laterally spaced within the channel from the second electrode, i.e., in use, some electrodes may be positioned above and below the slurry and some electrodes are positioned on either side of the slurry, allowing current to be passed vertically and / or laterally through the slurry.

[0122] In preferred embodiments, the electrodes are positioned at different points along at least a portion of the length of the channel between the exit and entry points of the conveyor belt. In some embodiments, the electrodes are positioned along a portion of the channel between the exit and entry points of the conveyor belt. This is referred to herein as the electrode area or L. 電極 , and the electrode area is defined as the area extending from the first electrode to the last electrode.

[0123] In some embodiments, the electrode area spans more than 40%, or more than 45%, or more than 50%, or more than 55%, or more than 60%, or more than 65%, or more than 70%, or more than 75%, or more than 80%, or more than 85%, or more than 90%, or more than 95% of the distance between the entry and exit points of the two or more conveyor belts. In some embodiments, the electrode area spans the entire length of the channel (i.e., the first electrode(s) is placed at (or substantially near) the entry of the channel and the last electrode(s) is placed at (or substantially near) the exit of the channel). In some embodiments, the electrode area is at least 3 meters long, or at least 4 meters long, or at least 5 meters long, or at least 6 meters long, or at least 7 meters long, or at least 8 meters long.

[0124] In some embodiments, at least some of the electrodes are near the entry point of the channel, i.e., at least some of the electrodes are within 2 meters, or within 1.5 m, or within 1 meter, or within 75 cm, or within 50 cm, or within 25 cm, or within 10 cm of the entry point. It is advantageous to apply ohmic heating to the slurry as close as possible to the entry point of the channel, since heating is used to increase the temperature of the material being processed, thus promoting the decomposition of resins present in the biomass composite and / or breaking the bonds between the resin and the fibers. In some embodiments, the electrode area follows the preheat area in the channel.

[0125] In some embodiments, the electrodes are arranged in at least two groups along the length of the channel, with each group including multiple electrodes (e.g., a first group of electrodes and a second group of electrodes). The at least two separate groups may be configured to pass different levels of current through the slurry along the length of the channel. In some embodiments, there are at least three separate groups along the length of the channel, or at least four, or at least five, or at least six, or at least seven, or at least eight, or at least nine, or at least ten separate groups along the length of the channel. The use of such groups allows for different current applications along the length of the channel, providing greater flexibility with respect to process control. In some embodiments, in use, the current applied to the first group of electrodes (e.g., located in a first portion of the channel) is greater than the current applied to the second group of electrodes (e.g., located in a second portion of the channel downstream of the first portion of the channel).

[0126] In some embodiments, there is a spacing between electrodes arranged in series along the length of the channel, or along a portion of the length of the channel (i.e., between the entry and exit points of two or more conveyor belts). By spacing between the electrodes, this therefore means that the slurry passes through areas of relatively higher or lower heat input. Thus, in such embodiments, the electrode spacing is appropriately selected such that the heating remains relatively consistent and controllable heating is achieved overall. In some embodiments, the spacing between the electrodes along the length of the channel is 0-4000 mm, preferably 30-500 mm. In other embodiments, the electrodes are arranged in series continuously such that there is no spacing between the electrodes.

[0127] The electrodes can have any suitable shape. In one embodiment and example, the electrodes are in the form of plates. In other embodiments, rod electrodes may be used. Rod electrodes have better contact with the water in the device, thereby reducing the current concentration near the electrodes and resulting in more consistent heating.

[0128] The electrodes may have any suitable size. In some embodiments, the electrodes are 1,000 to 10,000 mm 2 It has a size of

[0129] The electrodes may be formed from any suitable conductive material. In some embodiments, the electrodes are formed from metal or conductive carbon. In some embodiments, the electrodes are formed from steel (e.g., stainless steel), copper, titanium, gold, palladium, platinum, brass, silver, nickel, graphene, carbon nanotubes, or tungsten. In exemplary devices, steel and titanium coated electrodes have been found to work efficiently. Steel electrodes are particularly easy to machine and affordable.

[0130] In use, a potential difference is applied to the electrodes to generate a current through the slurry. The potential difference can generate a direct current (DC) or an alternating current (AC) through the slurry. In a preferred embodiment, an AC voltage is applied to the electrodes. This can extend the life of the electrodes and reduce gas generation at the electrodes that can be caused by electrolysis of water or brine.

[0131] In some embodiments, the device further comprises a power source. The power source may be any suitable power source. In some embodiments, the power source is a single-phase AC power source, which may provide more uniform heating. In other embodiments, the power source is a three-phase power source, which may be useful for higher power installations. In some embodiments, the device comprises thyristors, inverters, or solid-state relays (SSRs) for optimized power delivery. In some embodiments, the device further comprises a more complex power system, for example, the device comprises waveform and voltage regulation devices. These can cost-effectively deliver the required power to the device, limit the effects of electrical noise on the supply system, and match or convert available mains power to that required by the device.

[0132] In some embodiments, the electrodes can be supplied with power of about 1 kW to about 1500 kW, optionally about 10 kW to about 1500 kW, optionally about 20 kW to about 1500 kW. This can be about 1 kW to 100 kW, optionally 10 kW to 100 kW, optionally 20 kW to 100 kW, or 25 kW to 75 kW, or 40 kW to 60 kW, or about 50 kW for small installations, and up to 1500 kW for large installations. In some embodiments, the voltage applied to the electrodes is 100 to 450 V.

[0133] Baffle In some embodiments, the apparatus includes at least one baffle at an edge of the channel between two or more conveyor belts. Preferably, the apparatus includes two baffles at either edge of the channel between two or more conveyor belts. In some embodiments, the at least one baffle or two baffles are present only at the entry point of the channel.

[0134] The baffle(s) direct the biomass composite material and / or slurry away from the edges of the conveyor belt, reducing the chance of the material spilling over the edges as it expands along the length of the channel.

[0135] Upstream of the channel The apparatus may comprise further components or modules upstream of the channel, for example to pre-treat the biomass composite. Transport between the different parts of the apparatus may be by standard industrial screw or flat bed conveyors.

[0136] In some embodiments, the apparatus includes a mechanical disruption module located upstream of the channel. The mechanical disruption module can be used to chop the biomass composite material in order to break it down into smaller and more uniformly sized pieces. This allows a larger surface area of ​​the biomass composite material to be exposed to water when wetted to form a slurry. In some examples, the chopped biomass composite material is in the form of layered pieces, for example having the sizes described above. This allows a larger surface area of ​​the material to be exposed to water in the slurry. In some embodiments, downstream of the mechanical disruption module but upstream of the channel, there is a storage vessel for storing the chopped biomass composite material. The storage vessel may be in the form of a silo.

[0137] In one embodiment, downstream of the mechanical disruption module (if present) but upstream of the channel, the apparatus includes an automatic sieve. The automatic sieve may be in the form of a mesh conveyor, optionally using some degree of vibration to remove dust and particulates. In some embodiments, there is no automatic sieve upstream of the channel, since dust and particulates can be removed within the channel, for example, if two or more conveyor belts in the channel are formed of an open mesh material.

[0138] In one embodiment, the apparatus further comprises an induction magnet located upstream of the channel and downstream of the mechanical disruption module (if present), which can be used to remove magnetic (e.g., ferrous) metals or magnetic metal contaminants.

[0139] In one embodiment, the apparatus further comprises an eddy current separator located upstream of the channel and downstream of the mechanical destruction module (if present), which can be used to remove non-magnetic contaminants (e.g., screws, nails, fasteners, hinges, and other inserts that may form manufactured product waste).

[0140] In some embodiments, the apparatus further comprises one or more heating modules located upstream of the channel and downstream of the mechanical disruption module (if present) apparatus. The one or more heating modules can be used to preheat the slurry, biomass composite and / or liquid medium (e.g., water or brine) before entering the channel. This promotes fiber separation while in the channel and / or reduces energy consumption. In some embodiments, the heating module uses excess heat from other parts of the apparatus (i.e., from the reaction channel) to preheat the slurry, liquid medium water and / or biomass composite. In some embodiments (e.g., in non-pressurized apparatus), the one or more heating modules are configured to preheat the slurry, biomass composite and / or liquid medium (e.g., water) to a temperature between 30°C and 100°C, preferably between 50°C and up to 100°C, more preferably between 75°C and up to 100°C, or between 75°C and 95°C, or between 75°C and 90°C, or between 75°C and 85°C. In some embodiments, the one or more heating modules are configured to preheat the slurry, biomass composite and / or liquid medium (e.g., water) to a temperature of at least 30° C., or at least 40° C., or at least 50° C., or at least 60° C., or at least 70° C., or at least 75° C., or at least 80° C. In some embodiments (e.g., in a pressurized apparatus), the one or more heating modules are configured to preheat the slurry, biomass composite and / or liquid medium (e.g., water) to a temperature of up to 200° C.

[0141] In some embodiments, the device includes insulation (eg, around the channels) to prevent unwanted heat loss and retain heat for circulation.

[0142] In one embodiment, the apparatus comprises a wetting module upstream of the channel and downstream of the mechanical disruption module (if present). The wetting module may be in the form of a wetting tank. The wetting module contains a liquid medium (e.g., water), and the purpose of the wetting tank is to form a slurry and wet the biomass composite fibers before they enter the channel. The wetting module may be used to pre-wet the biomass composite before it enters the channel, e.g., to form a slurry. In some embodiments, the wetting module may be configured to heat the liquid medium (e.g., water), and in some embodiments, the wetting module may be integral with the heating module.

[0143] In some embodiments, the apparatus does not include a wetting module upstream of the channel. This may be the situation where the biomass composite material instead wets and forms a slurry within the channel.

[0144] In some embodiments, the apparatus further includes a feeding system for feeding the biomass composite and / or slurry onto the lower belt of the two conveyor belt system. Examples may include storage containers and automatic feeding; rotary release valves, screw conveyor feeding (e.g., for dry biomass composite entering the channel), pneumatic feeding systems, or scraper action for vertical feeding (e.g., leveling bars). The feeding system can be used to ensure uniform and even distribution of the biomass composite on the lower belt of the conveyor (i.e., the first belt). The feeding system can be used to ensure a stable depth of material (i.e., 5-50 cm of slurry or biomass composite so that the process can be efficiently controlled).

[0145] In some embodiments, the apparatus further comprises a liquid medium delivery system (e.g., a water delivery system) for delivering liquid medium (e.g., water) to the channels. The liquid medium delivery system may comprise a dosing pump and / or a conductivity controller. The liquid medium delivered to the channels can be used to replace liquid medium absorbed within the biomass composite material and / or can be used to fill the flow paths.

[0146] In some embodiments, the apparatus further comprises a recirculation unit (e.g., a water recirculation unit) for circulating a liquid medium (e.g., water) in and out of the channel. 3 The liquid medium can be circulated at a rate of 10000 / hr.

[0147] In some embodiments, a recirculation unit can be used to heat and / or maintain the temperature of the apparatus (thereby reducing energy consumption). This can be useful to prevent the liquid medium (e.g., water) from becoming too hot due to heat generated by the flow of electrical current in the liquid medium, compared to the heat generated in the biomass composite being processed. In some embodiments, the water recirculation unit may include a filtration system, which can be used to filter the liquid medium (e.g., to filter out resin and / or to wash the liquid medium).

[0148] Additionally and alternatively, a liquid medium circulation unit (e.g., a water recirculation unit) is configured to recirculate liquid medium removed during the drying process (e.g., during mechanical compression) into the channels. This can be useful for returning heat to the channels and / or the apparatus. This is also useful for recovering and reusing liquid medium so that the apparatus operates in a more sustainable and environmentally friendly manner.

[0149] Additionally or alternatively, in other embodiments, a liquid medium recirculation unit (eg, a water recirculation unit) can be used to purge the channels of solid and dissolved contaminants.

[0150] In some embodiments, the apparatus may further comprise a filter or screen. In the case of solids, mainly comprising wood fibers, escaping containment between the conveyor belts, these solids can be collected in a filter or screen to improve overall fiber recovery from the apparatus.

[0151] In some embodiments, the apparatus further comprises a near-infrared (NIR) (or other machine vision camera) separation system upstream of the channel, which allows contaminants to be identified and removed from the incoming feedstock, thereby increasing the purity of the material being processed.

[0152] Downstream of the channel The apparatus may comprise further modules downstream of the channel. Transport between the channel and different parts of the apparatus downstream of the channel may be by standard industrial screw or flat bed conveyors. In some embodiments, the apparatus comprises a double belt wire or mesh press downstream of the channel for dewatering. In some embodiments, the apparatus may comprise a dewatering device located downstream of the channel, for example a plug screw dewatering device. In some embodiments, the biomass is dewatered after ohmic heating, for example downstream of the channel, so that the moisture content is 70% by weight or less, preferably 60% by weight or less, 60% by weight or less. By dewatering (e.g. mechanically using a dewatering device), this can minimize energy consumption in the evaporative heating process. In some embodiments, the apparatus may further comprise one or more of a deagglomeration module, a washing module, or a drying module downstream of the channel. In some embodiments, the deagglomeration module, the washing module, and the drying module are separate modules. In other embodiments, one or more of the deagglomeration module, the washing module, or the drying module are integrated into one module.

[0153] In some embodiments, downstream of the channel, the apparatus may further comprise a deagglomeration module for de-clumping or de-agglomerating the separated fibers. The deagglomeration means may be in the form of an optionally heated agitated vessel or rotating cylinder. The deagglomeration means may comprise an airflow system to achieve the effect of loosening the fibers from remaining agglomerates. In other embodiments, the deagglomeration means may comprise a mechanical agitation means, for example an in-line ribbon blender module.

[0154] In one embodiment, downstream of the channel is a cleaning module. In some embodiments, the cleaning module is in the form of a flotation separation device. In additional or alternative embodiments, the cleaning module may comprise an air separation device, such as a cyclone separator, which may be used to remove non-fibrous or incompatible contaminants. This may be used to allow for the removal of heavier, denser particles from the separated fibers (i.e., while retaining the lighter fibers).

[0155] In one embodiment, downstream of the channel of the device is a drying module for drying and / or discharging the recovered fibers. In some embodiments, the drying means comprises a component for drying by pressing or blowing. This is preferred over drying means for drying by evaporation alone, as it has a much lower energy demand. In some embodiments, the drying module is in the form of a mechanical press. In some embodiments, the drying means is in the form of a high-pressure nozzle. In some embodiments, the mechanical drying achieves a moisture content of less than 500 g of liquid medium (e.g., water) per kg of fiber. In some embodiments, the drying module alternatively or additionally comprises a component for drying by evaporation. In some embodiments, the drying module comprises a ring dryer, a flash dryer, a rotary dryer or a fluidized bed dryer. In some embodiments, the drying by evaporation achieves a moisture content of less than 150 g of liquid medium (e.g., water) per kg of fiber, more preferably less than 100 g of liquid medium (e.g., water) per kg of dry fiber.

[0156] In one embodiment, downstream of the channel, the device further comprises a processing plant for producing biomass composite articles from the separated and recovered fibers. For example, if the biomass composite is MDF, the processing plant is an MDF production line. In some embodiments, the MDF production line does not include a refinery. It is a preferred solution that the separated fibers are integrated after the refining step of standard MDF production. This avoids the most energy-intensive operation of the process and ensures that the shortening / degradation of the fibers in the refiner is avoided.

[0157] In one embodiment, downstream of the channel, the apparatus further comprises a processing plant for producing a fiber insulation board, for example a wood fiber insulation board, which may be a flexible or rigid insulation board.

[0158] method The methods of the present invention can be carried out using the devices described herein.

[0159] The method includes providing a slurry comprising a liquid medium (e.g., water) and a biomass composite material. In some embodiments, the slurry is provided by mixing the biomass composite material with a liquid medium (e.g., water), in other words, wetting the biomass composite material. In some embodiments, the mixing and / or wetting occurs prior to entering the channel, e.g., in a wetting module upstream of the channel. In other embodiments, the mixing and / or wetting occurs within the channel, e.g., by feeding the biomass composite material into the channel and wetting the biomass composite material with the liquid medium (e.g., water) within the channel.

[0160] In some embodiments, the biomass composite may be chopped in a chopping step prior to providing the slurry. In some embodiments, the biomass composite is chopped into pieces, which may be layered pieces, at least a portion of which (preferably at least 25% (by number), optionally at least 50% (by number), optionally at least 75% (by number)) have a length of 10-45 mm, preferably 30-40 mm, measured along their longest dimension. In some embodiments, the biomass composite is chopped into pieces, which may be layered pieces, at least a portion of which (preferably at least 25% (by number), optionally at least 50% (by number)) have a thickness of 3-10 mm, measured along their shortest dimension.

[0161] In some embodiments, prior to providing the slurry, the biomass composite is treated with an induction magnet and / or an eddy current separator to remove contaminants.

[0162] In some embodiments, prior to providing the slurry, the biomass composite and / or water are preheated, for example in a heating module upstream of the channel. In some embodiments, the biomass composite, liquid medium (e.g., water) and / or slurry are heated to a temperature of 50° C. up to 100° C., or 75° C. up to 100° C., or 75° C. to 95° C., or 75° C. to 90° C., or 75° C. to 85° C. In some embodiments, providing the slurry (i.e., wetting the biomass composite) and preheating are performed in an integrated process.

[0163] In some embodiments, after providing the slurry (i.e., after wetting the biomass composite material), but before moving the slurry through the channel, the slurry is heated, for example, in a heating module upstream of the channel. In some embodiments, the biomass composite material, liquid medium (e.g., water), and / or slurry are heated to a temperature of 50 up to 100° C., or 75° C. up to 100° C., or 75° C. to 95° C., or 75° C. to 90° C., or 75° C. to 85° C. In some embodiments, the heating is performed at atmospheric pressure.

[0164] In the method of the invention, the slurry moves through a channel via two or more conveyor belts, and the biomass composite material is placed between the two or more conveyor belts. In some embodiments, the biomass composite material is present between the two or more conveyor belts at a depth of 5 cm to 50 cm. In some embodiments, the biomass composite material is present between the two conveyor belts at a depth of at least 5 cm, or at least 10 cm, or at least 15 cm, or at least 20 cm, or at least 25 cm, or at least 30 cm, or at least 35 cm. In some embodiments, the biomass composite material is present between the two conveyor belts at a depth of less than 50 cm, or less than 45 cm, or less than 40 cm, or less than 35 cm, or less than 30 cm, or less than 25 cm, or less than 20 cm, or less than 15 cm, or less than 10 cm.

[0165] In some embodiments, the belt speed of the two or more conveyor belts is in the range of up to 100 mm / s, or between 2 mm / s and 50 mm / s, in some embodiments between 3 mm / s and 15 mm / s, in some embodiments between 4 mm / s and 10 mm / s, in some embodiments between 5 mm / s and 8 mm / s, in some embodiments, the belt speed of the two or more conveyor belts is at least 2 mm / s, or at least 3 mm / s, or at least 4 mm / s, or at least 5 mm / s, or at least 6 mm / s, or at least 7 mm / s, or at least 8 mm / s. In some embodiments, the belt speed of the two or more conveyor belts is less than 20 mm / s, or less than 19 mm / s, or less than 18 mm / s, or less than 17 mm / s, or less than 16 mm / s, or less than 15 mm / s, or less than 14 mm / s, or less than 15 mm / s, or less than 14 mm / s, or less than 13 mm / s, or less than 12 mm / s, or less than 11 mm / s, or less than 10 mm / s, or less than 9 mm / s, or less than 8 mm / s, or less than 7 mm / s, or less than 6 mm / s, or less than 5 mm / s, or less than 4 mm / s, or less than 3 mm / s.

[0166] In some embodiments, the slurry has a residence time in the channel of at least 2 minutes, or at least 3 minutes, or at least 4 minutes, or at least 5 minutes, or at least 6 minutes, or at least 7 minutes, or at least 8 minutes, or at least 9 minutes, or at least 10 minutes, or at least 12.5 minutes, or at least 15 minutes, or at least 17.5 minutes, or at least 20 minutes, or at least 30 minutes, or at least 40 minutes, or at least 60 minutes, or at least 120 minutes. In some examples, the residence time is about 15 to 45 minutes. Higher density materials may require longer residence times and may take longer to process.

[0167] In some embodiments, the biomass composite moves through the channel at a rate of 200 kg / hr to 10 tons / hr. In some examples, the biomass composite moves through the channel at a rate of 2.6 to 3.1 tons / hr. In some examples, the method can be run at at least 400 kg / hr, which has proven to be very cost effective in some circumstances.

[0168] The method includes passing an electric current through the slurry to heat the biomass composite to achieve separation of the fibers in the biomass composite. Heating the biomass composite with an electric current may alternatively be described as ohmic heating. In some embodiments (e.g., in a non-pressurized apparatus), the biomass composite, water and / or slurry are heated or maintained in the channel at a temperature of 50°C to 100°C, or 60°C to 100°C, or 75°C to 100°C, or 75°C to 90°C, or 75°C to 85°C. Chemical bonds between the resin and the fibers in the biomass composite may be broken down during this process, and / or the resin material is decomposed, leading to separation of the biomass fibers. In other embodiments (e.g., in a pressurized apparatus), the biomass composite, water and / or slurry are heated or maintained at a temperature of up to 200°C.

[0169] In a preferred embodiment, the heating is carried out at atmospheric pressure. In other embodiments, the method may include the use of high pressure within the channel.

[0170] In an embodiment, the heating is carried out at above atmospheric pressure, for example up to 20 barg.

[0171] In some embodiments, the passage of current is accomplished by applying a voltage to electrodes placed within the channel. In some embodiments, the applied voltage is between 100 and 450 V, such as between 200 V and 450 V, or 240 V±25 V or 400 V±25 V.

[0172] In some embodiments, the total power applied to the electrodes is between 1 kW and 1500 kW, optionally between 10 kW and 1500 kW, optionally between 20 kW and 1500 kW, or between 1 kW and 1000 kW, optionally between 10 kW and 1000 kW, optionally between 20 kW and 1000 kW, or between 1 and 500 kW, optionally between 10 and 500 kW, optionally between 20 and 500 kW, or between 1 and 100 kW, optionally between 10 and 100 kW, optionally between 20 and 100 kW, or between 25 and 75 kW, or about 40 and 50 kW. In some embodiments, the electrodes are segregated into one or more arrays within the channel, and the power supplied to the electrode array in a first portion (or half) of the channel is greater than the power supplied to the electrode array in a second portion (or half) of the channel. In some embodiments, at least 55%, or at least 60%, or at least 65%, or at least 70%, or at least 75% of the power is delivered to the electrode array in the first portion (or half) of the channel.

[0173] In some embodiments, the energy per unit mass of the biomass composite is between 20 kWh / ton and about 500 kWh / ton. Depending on the level of processing, the energy per unit of the biomass composite can be more or less.

[0174] After moving the slurry through the channel and applying an electric current to the slurry, the separated fibers are collected. In some embodiments, the separated fibers are collected after exiting the channel. In some embodiments, after exiting the channel (i.e., in a deagglomeration, washing or drying module), the separated fibers are subjected to one or more of deagglomeration, washing or drying before collecting the separated fibers.

[0175] In some embodiments, the separated fibers are subjected to a wet washing process after exiting the channel. In some examples, the wet phase washing involves diluting the separated fibers with water (e.g., the water contains 2% to 20% solids by weight). The separated fibers may then be subjected to a mechanical agitation process (e.g., to further separate and / or deagglomerate the fibers). The separated fibers may then be screened using one or more filters to remove contaminants. In some embodiments, the separated fibers then undergo a drying process, e.g., in a drying module, e.g., using a mechanical press.

[0176] In an alternative embodiment, the separated fibers are subjected to a dry-washing process after exiting the channel. This allows for proper storage and transportation of the recovered fibers and avoids biological degradation of the recovered fibers after production. Dry-washing also facilitates flexibility to address multiple end markets for the recovered fibers, many of which are dry manufacturing environments. In the dry-washing process, the separated fibers are dried, for example, using a mechanical press and / or using a ring dryer, flash dryer, rotary dryer, or fluidized bed dryer. The separated fibers are then washed, for example, using a cyclone separator or a series of separators. This allows heavier and denser particles to be removed from the air stream while retaining the lighter biomass fibers.

[0177] The recovered fibers can be used for further processing. In some methods, the separated and recovered fibers may be sent to a processing plant for the production of recycled biomass composites, for example, recovered wood fibers, and sent to an MDF production plant.

[0178] Separated / recovered fibers According to a fourth aspect, the separated fibers are produced according to the method disclosed herein. The separated fibers may be called regenerated or reclaimed fibers or rMDF in other cases. For example, if the biomass composite is MDF, the recovered fibers are regenerated MDF fibers. In some aspects, the separated fibers may be used in fiberboard manufacturing industry. In other aspects, the separated fibers may be used in insulation materials, as fillers for plastic or cement composites, as spill absorbents, or in horticultural growing media.

[0179] In some embodiments, the separated fibers may be clumps of fibers, while in other embodiments, the separated fibers may be individual fibers.

[0180] Recycled Biomass Composites According to a fifth aspect, there is a recycled biomass composite material that includes or is formed using the separated fibers (or recycled fibers) disclosed herein.

[0181] The recycled biomass composite material may be an engineered wood material, such as fiberboard or particleboard, hi some embodiments, the recycled biomass composite material is MDF. EXAMPLES

[0182] Exemplary Apparatus An exemplary apparatus of the present disclosure will be described with reference to FIG.

[0183] The apparatus comprises a reaction channel (1) which, in use, is filled with brine (2). The channel has a length (L) of about 10 metres (the length being defined as the length of the base of the channel). However, other suitable lengths may be used.

[0184] Within the channel are placed two independent conveyor belts, namely a lower belt (3a) and an upper belt (3b) (which may otherwise be referred to as a first belt and a second belt, respectively). The belts are formed of non-conductive PTFE (Teflon coated Kevlar mesh), although other suitable materials may be used. The belts have a width of 300 mm and a mesh opening size of 1 mm to 3 mm. In the channel, the lower belt and the upper belt are placed on top of each other with a space in between (i.e., due to the presence of the biomass composite material and slurry). Both the lower belt (3a) and the upper belt (3b) are fed into the channel to form an entry point (4). The two conveyor belts extend along the length of the channel, separate, and are fed out of the channel at an exit point (5). The two conveyor belts are adapted to (i) feed the biomass composite material into the channel, (ii) move the slurry through the channel (i.e., from the channel inlet to the channel outlet), and (iii) pull the fibers out of the channel.

[0185] In use, the biomass composite material is fed into the channel by the lower belt 3a. The upper belt 3b also descends into the channel to sandwich or trap the biomass composite material, forming an entry point (4). The channel is filled with brine, so that the lower belt 1a, upper belt 1b and the biomass composite material are submerged in water.

[0186] Two conveyor belts move the biomass composite material along the length of the channel (i.e., in the direction of the arrows (see FIG. 1)), and the belts are driven by a number of rollers (9). The two conveyor belts hold the slurry and biomass composite material in place.

[0187] In the apparatus of Figure 1, the distance between the two conveyor belts increases along the length of the channel, whereby the lower conveyor belt slopes downwards along the length of the channel. In use, this allows the material to expand as it is drawn through the apparatus. In this exemplary apparatus, there is a distance of 200 mm at the entry point where the two conveyor belts feed into the channel (4), and a distance of 300-350 mm at the exit point where the two conveyor belts feed out of the channel (5). However, other suitable distances may be used.

[0188] Above and below the channel are placed a series of electrodes (6a and 6b). In this example, the series of electrodes are positioned below (6a) and above (6b) the channel. The first electrode in the series to the last electrode in the series define an electrode area (7). The electrode area has a length (L) of about 5 meters. E ), although any suitable length may be used. The electrodes are stainless steel, although any conductive material may be used. Each electrode is in the form of a flat plate measuring 30 mm by 300 mm. Although not shown in FIG. 1, power delivery to the electrodes may be optimized by the use of a control device comprising, for example, one or more thyristors or inverters. In use, an applied voltage is applied to the electrodes such that current flows through the slurry and the biomass composite to heat the biomass composite. This causes the fibers to separate due to the breakdown of chemical bonds in the biomass composite that hold the biomass composite together and / or the breakdown of resins in the biomass composite.

[0189] In use, brine (2) is pumped into the channel via a water feed system (8). Although not shown, the operating level of water (brine) is maintained by an automated system that continuously adds more water (brine) to the device channel. The water pumped into the channel can pass through a mesh conveyor belt and can be used to wet the biomass composite and / or to replace water absorbed by the biomass composite. The water in the slurry between the two conveyor belts in the channel allows a conductive path to form between the electrodes.

[0190] 1, the distance between the belts increases along the length of the device between the entry and exit points, however, in other embodiments, the distance between the belts may remain substantially constant over the length of the device. Additionally, while in this example, electrodes are positioned above and below the channel, additionally or alternatively, electrodes may be placed on both sides of the channel.

[0191] In FIG. 1, a mesh material is used for the belt, however, a non-mesh belt can be used as long as the biomass composite material used is pre-wetted or there is at least one opening in the belt to allow water to pass through and into the area between the two conveyor belts.

[0192] Although not shown in Figure 1, the apparatus may further include one or more baffles at the inlet of the channels on each side of the lower belt 1a to direct the material away from the edges of the belt (i.e., so that the belt does not fill up to the edges) so that the biomass composite material does not overflow the edges of the belt.

[0193] Although not shown in FIG. 1, the apparatus may further include the use of drivers and / or rollers to support or increase the stiffness of the belt arrangement.

[0194] Although not shown in FIG. 1, the apparatus may further include a tensioning system (e.g., a pneumatic, hydraulic, electric, or mechanical tensioning system) to achieve good tension between the belts, which can automatically adjust to the operating conditions such that the apparatus is sufficient to contain the biomass composite material between the belts and transport the material through the channel as the belts move.

[0195] Although not shown in Figure 1, upstream of the channel, the apparatus may further comprise one or more of a mechanical disruption module, a wetting module, or a pre-heating module. In some embodiments, heating and wetting may occur in the same vessel in an integrated process.

[0196] Although not shown in Figure 1, after the conveyor exits the channel, the conveyor may include an elongated section that allows water to drain before separation. Drainage may be assisted by compression, for example by a mechanical press.

[0197] Although not shown in Figure 1, after exiting the channel, the conveyor belt delivers the separated fibers to one or more of a deagglomeration module, a washing module, and / or a drying module. In some embodiments, deagglomeration, washing, and / or drying may occur in the same vessel in an integrated process.

[0198] Although not shown in FIG. 1, excess water (from the exhaust or drying module) can be removed and returned to the channel by a water recirculation unit. This water removal process can be beneficial because it allows electrolyte (if present) and water to be returned to the device and prevents dissolved contaminants from entering subsequent processing steps. If the water is heated, this also provides a mechanism for returning heat to the device. If the next stage is a drying step, this initial water removal reduces the load and therefore the size and cost of the subsequent drying equipment. If the next processing step is a wet phase wash, removal of contaminants can be important.

[0199] Comparative Example: The inventors have considered, designed or tested many other delivery systems in combination with ohmic heating channels but have not found these to be suitable, as will be explained in more detail below.

[0200] Pumped Systems - Pumped systems have been found to be prone to blockages and breakdowns, i.e., due to incompatibility with the feedstock, which expands as the reaction proceeds. To reduce the degree of blockage and breakdown, highly dilute slurries can be used, but highly dilute slurries are very inefficient for the process and ohmic heating.

[0201] Screw conveyor systems- Similar problems with expansion were observed for screw conveyor systems. Screw conveyor systems were found to be less compatible with feed materials that expand as the reaction progresses. Additionally, screw conveyor systems had problems with irregularly shaped input materials that easily bridge in the pipe due to the Janssen effect. The Janssen effect describes the mechanical behavior of particles within a confined geometry such as a column or pipe, whereby frictional forces between the particles and the walls of the vessel cause the material to become immobile and behave like a solid rather than a granular mass, thus preventing flow through the confined geometry.

[0202] Tubular Drag Conveyor Systems - Tubular drag conveyor systems were not found to be suitable due to the limited capacity of the system due to their inherent strength of the cable design. There were further difficulties and incompatibility with this system in handling the solid biomass composite material which is forced into the gaps between the disks of the tubular drag conveyor system.

[0203] Single Conveyor Belt System - A single conveyor belt is routinely used for transporting materials, but this was not adapted for transporting a slurry containing biomass composite and water. It was found that the single conveyor did not have enough drag to draw the slurry through the reactor channel.

[0204] Pneumatic Air Conveyor Systems - Pneumatic air conveyor systems are not suitable for use with liquids or water, therefore the creation of a conductive path is not possible which would preclude the use of ohmic heating.

[0205] Detailed example of processing method An exemplary process method was carried out in an apparatus substantially similar to that described above, except that the electrodes were located on both sides of the channel (as opposed to the top and bottom of the channel).

[0206] MDF board feedstock is prepared by chipping MDF into pieces approximately 30mm-40mm long and wide, and 3-10mm thick. MDF board feedstock contains 85-95% wood fibre and 5-15% urea formaldehyde resin. The dry density of MDF board feedstock is 750-850kg / m 3 is within the range.

[0207] A brine solution is prepared with a conductivity of 600 mS / m and heated to a temperature of 80° C. The channel is filled with the brine solution. The working level of water in the channel is above the level of the upper belt and was maintained by an automated system that continuously adds more brine to replace the water absorbed by the MDF chips.

[0208] Dry MDF chips are introduced into the channel via a lower conveyor belt at a rate of 150 kg / hour. The MDF chips are spread in an even layer across the lower belt with an initial depth of about 50 mm. It has been found to be advantageous to allow a gap of approximately 25 mm on each side of the belt to prevent the material from spilling over the edges of the belt as it expands. This can be achieved by using an apparatus with baffles on each side of the belt at the entrance to the apparatus.

[0209] As the MDF material moves into the device, the upper belt descends to restrain the material and the entire arrangement is submerged in the brine. The twin belt arrangement helps hold the wood chips in place, forcing them to sink as they would otherwise naturally float. The slurry and biomass composite is moved through the channel at a speed of 5mm / s. This ensures a dense slurry as the two conveyors compress the biomass due to the tension of the belts.

[0210] To achieve a stable operating temperature of about 80°C, ohmic heating is applied via an array of electrodes installed on either side of the material in the device channel. In this example, a total power of about 50 kW is applied across the electrode array. In this example, the electrodes in the device are electrically isolated into several groups, and the power input to each group of electrodes can be modulated according to various requirements by pulse width modulation of the applied waveform. In this example, significantly more power, e.g., about 75% of the total, is applied to the electrodes located in the first half of the device channel compared to the second half of the device channel. This is found to give better results in terms of the speed at which the material is processed. Although this example was used with electrodes installed on the sides of the channel, modeling suggests that electrodes installed horizontally on the top and bottom of the channel may provide more efficient production and lower energy loads (see Figure 3 and table below).

[0211] [Table 1]

[0212] [Table 2]

[0213] When the equipment is running, the operator must monitor the achieved composition of the product in order to adjust the process parameters.

[0214] Power may be adjusted between 20-60 kW, typically 40 kW, to achieve the desired degree of breaking of the chemical bonds between the resin and the fibers, or decomposition of the resin. Alternatively or additionally, the conveyor speed may be adjusted from 1 to 12 mm / s, or the temperature may be increased or decreased to a temperature of about 100°C. The applied power and operating parameters may depend on the density of the composite, the mass flow rate of the slurry (faster flow rates of the slurry may require more power to be applied), the temperature of the slurry, and the amount of heat loss of the equipment (which may depend on the geometry, insulating qualities and external temperature of the equipment). For example, a higher density of the composite will typically require more power to be applied, but a higher temperature of the slurry may mean that less power or a faster flow rate can be used. In either case, the operator may monitor the composition of the product to adjust the processing parameters. If the product is minimally processed (e.g., there are pieces of untreated MDF chips in the product) and a higher degree of processing is required, the applied power can be increased, the temperature can be raised, or the conveyor speed can be reduced, which has the effect of increasing the power delivered per unit of material processed. If the material is over-processed (e.g., there is significant fiber expansion and brine absorption into the wood fibers), the opposite adjustments are made.

[0215] During processing, chemical bonds between the resin and the fibers present in the MDF may break down, releasing wood fibers and / or the resin may decompose. This results in the conversion of solid MDF chips to wood fibers that form a sponge-like compressible matrix. This may cause the material to expand by approximately five times (the level of expansion depends on the quality of the original MDF board and the processing conditions). Part of this expansion may be facilitated by the wood fibers filling the voids that were present in the original pile of MDF chips. Expansion may also be enabled by the flexibility of the belt system while keeping the material restrained and transported through the equipment. Expansion is also assisted by the spacing between the belts, which increases between the inlet and outlet of the equipment.

[0216] At the exit of the channel, two conveyor belts leave the brine, the upper belt separates it from the treated material. Typically, when the wood fibres leave the device channel, they are accompanied by about 600 kg of brine, which is partially absorbed by the material. The lower belt can deliver these fibres to a subsequent processing step.

[0217] In some embodiments, separation of the belts can occur after an elongated section of the two conveyor belts to aid in dewatering.

[0218] During processing in the equipment, the MDF chips may have been reduced to individual wood fibers or clumps of fibers, which exit the equipment as a mat of material. The individual wood fibers can be recovered since they are no longer bound together by the resin. The consistency of the product can be varied by manipulating the equipment to achieve various degrees of processing. Figure 4 shows the conversion of MDF chips input into the equipment (A) after processing (B).

[0219] final result At the minimum degree of processing that would be most efficient in commercial operations (e.g., when the energy per unit mass of material processed is about 40 kWh / ton), the end result is separated fibers that have been clumped together corresponding to the initially fed MDF chips, and this grouping can be physically identified in the product and individually handled as chunks of material. This type of material can be further broken down by light mechanical action, for example, by mixing with water in an agitated vessel, or by combing or beating type action against the bulk material.

[0220] At higher treatment intensities (for example, when the energy per unit mass of material being treated is about 80 kWh / ton), the wood fibers are completely freed of their original associations and no trace of the fed MDF chips can be discerned. Either after drying or when the material is diluted with water, an essentially uniform mat of fibers is produced, with the individual fibers readily accessible.

Claims

1. 1. An apparatus for recovering separated fibers from a biomass composite material, comprising: a channel configured to receive a slurry comprising a liquid medium and a biomass composite material; two or more conveyor belts configured to move the slurry through the channel, whereby, in use, a biomass composite material is placed between the two or more conveyor belts; and a plurality of electrodes disposed within the channel configured to pass an electric current through the slurry to heat the biomass composite material and achieve separation of the fibers in the biomass composite material; An apparatus comprising:

2. The apparatus of claim 1 , wherein the distance between the two or more conveyor belts increases along the length of the channel.

3. 3. An apparatus according to any one of claims 1 to 2, wherein the two or more conveyor belts are formed of a non-conductive mesh material, preferably the mesh material comprises a polymeric material, preferably the polymeric material is selected from para-aramid and polytetrafluoroethylene (PTFE), optionally PTFE coated para-aramid.

4. 4. The apparatus of any one of claims 1 to 3, wherein, in use, the electrodes are arranged such that a first electrode is spaced from a second electrode to allow the slurry to pass between the first and second electrodes and the current to pass between the first and second electrodes, and wherein, in use, the first and second electrodes are located at different vertical heights within the channel and / or the first electrode is spaced laterally within the channel from the second electrode.

5. 5. The apparatus of claim 1, wherein the electrodes are arranged in at least two groups along the length of the channel, each of the groups configured to pass a different level of electrical current through the slurry along the length of the channel.

6. An apparatus according to any one of claims 1 to 5, wherein the apparatus comprises at least one baffle on a side of a channel between the two or more conveyor belts.

7. 1. A method for recovering separated fibers from a biomass composite material, comprising: providing a slurry comprising a liquid medium and a biomass composite material; moving the slurry through a channel using two or more conveyor belts, the biomass composite material being placed between the two or more conveyor belts; and applying an electric current to the slurry while the biomass composite material is between the conveyor belts to heat the biomass composite material and effect separation of the fibers in the biomass composite material; and and recovering the separated fibers.

8. A method according to claim 7, carried out using an apparatus according to any one of claims 1 to 6.

9. The method according to any one of claims 7 to 8, wherein the biomass composite material is heated between 50 and 100°C, preferably between 75°C and 100°C.

10. The method of any one of claims 7 to 9, wherein the slurry is provided by feeding the composite biomass material into the channel and wetting the composite biomass material with water within the channel.

11. A method according to any one of claims 7 to 10, wherein the belt speed is in the range up to 100 mm / s, preferably between 2 mm / s and 50 mm / s.

12. A method according to any one of claims 7 to 11, wherein the composite biomass material is chopped into pieces, preferably at least some of which are 1045mm along their longest dimension.

13. A method according to any one of claims 7 to 12, wherein the liquid medium comprises or is water.

14. 14. The method of claim 13, wherein the water further comprises an electrolyte, and preferably the liquid medium comprises or is a brine.

15. 15. The method of any one of claims 7 to 14, wherein the ratio of liquid medium to composite biomass in the slurry is from 20:1 to 1:1 by weight, optionally from 15:1 to 1:1 by weight, optionally from 8:1 to 2.5:1 by weight.

16. The apparatus of any one of claims 1 to 6 or the method of any one of claims 7 to 15, wherein the biomass composite material comprises lignocellulosic fibers.

17. An apparatus according to any one of claims 1 to 6 or a method according to any one of claims 7 to 16, wherein the biomass composite material is an engineered wood material and the fibres are wood fibres.

18. 17. The apparatus or method of claim 16, wherein the biomass composite material is selected from softboard, MDF, HDF and particleboard.

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