Process for the production of recycled lignocellulose fragments

Description

1 / 31 “PROCESS FOR THE PRODUCTION OF RECYCLED LIGNOCELLULOSE FRAGMENTS”

[0001] The present invention relates to a process for the production of recycled lignocellulose fragments, for example, recycled wood fibers or recycled wood chips. This invention also relates to a process for the production of lignocellulose-based panels, for example, wood fiberboard panels – such as MDF (Medium Density Fiberboard) or HDF (High Density Fiberboard), or soft or hard panels – in which recycled lignocellulose fragments obtained from the recycling of lignocellulose-based panels – for example, from the recycling of MDF (Medium Density Fiberboard) and / or from the recycling of HDF (High Density Fiberboard) panels and / or from the recycling of soft and / or hard panels – are used, at least to some extent, as raw material.

[0002] WO2011 / 077155A1 describes a method for recycling “engineered wood panels”, such as wood fiber panels, in which wood fibers are recovered that can be used as substitutes for new wood fibers.

[0003] US2003 / 0056873A1 describes a process for the production of wood fiber panels – by recycling waste wood composite products – using a conventional dry production process. The process employs a modified treatment in a preheater, followed by mechanical refining in a refiner, resulting in recycled fibers. In the preheater, the recycled wood products are chemically treated under pressure in the presence of steam. A disadvantage of this process is the need to add chemicals in the preheater.

[0004] WO2005 / 007968A1 refers to a method for recovering wood constituents from a panel material. Petition 870250086477, dated 09 / 24 / 2025, page 8 / 56 2 / 31 Made from a lignocellulose matrix bonded by glue. The method involves treating the material with a combination of electromagnetic radiation and immersion in a liquid medium, and recovering the constituents. A disadvantage is the need for special equipment to generate the electromagnetic radiation necessary to heat the material, as well as the difficulty of incorporating such a process into a continuous process.

[0005] WO01 / 39946A1 describes a process for the production of fiberboard panels by recycling waste from wood composite products using a conventional continuous dry wood fiberboard panel process, wherein the process in the preheater and / or refiner is modified. These modifications ensure the production of fiberboard panels containing at least 20% by weight of recycled fibers.

[0006] One problem with prior art recycling methods for recycling MDF and HDF panels is that they require complex equipment, are difficult to incorporate into existing production processes for particleboard, MDF or HDF panels, are not economically viable and do not result in the required and consistent quality of panels produced with the recovered material.

[0007] WO 2023 / 031763 A1 describes, among other things, a process for the production of wood fiber panels, in which recycled wood fibers are produced and in which these recycled wood fibers are used to form new wood fiber panels.

[0008] One objective of the invention is to offer a solution to deficiencies in the recycling processes of lignocellulose-based boards and panels into recycled lignocellulose fragments and to improve the production of new lignocellulose-based boards comprising recycled lignocellulose fragments. Petition 870250086477, dated 09 / 24 / 2025, p. 9 / 56 3 / 31

[0009] The invention, according to a first aspect, relates to a process for the production of recycled lignocellulose fragments, such as recycled wood fibers or recycled wood chips, wherein the process comprises a first step in which refined material from recycled lignocellulose-based boards or panels - preferably recycled MDF or HDF - is introduced into a container and moistened, heated and pressurized using steam; wherein the process optionally comprises a second step in which this material is maintained under pressure and temperature for a specified period of time in said container, wherein the process comprises a third step of steam explosion of the moistened, heated and pressurized material, wherein the pressure in the container is reduced by at least 3 bar, and preferably by at least 5 bar, more preferably by at least 7 bar; more preferably by at least 10 bar, more preferably by at least 11 bar;and in which recycled lignocellulose fragments, such as recycled wood fibers or recycled wood chips, are produced during said steam explosion; wherein the steam explosion is a multistage steam explosion, meaning that the pressure reduction occurs in at least two partial stages, wherein the multistage steam explosion comprises at least a first partial stage in which the pressure in the vessel is reduced and a subsequent second partial stage in which the pressure in the vessel is further reduced, wherein a first ratio between the pressure drop in the first partial stage and the duration of the pressure reduction in the first partial stage is less than a second ratio between the pressure drop in the second partial stage and the duration of the pressure reduction in the second partial stage.

[0010] Preferably, at least two partial stages are clearly distinguishable from each other. This can be done by means of Petition 870250086477, dated 09 / 24 / 2025, page 10 / 56 4 / 31 one or more of the following options: - a valve or flap that can assume different positions (for example, fully open or partially open), where, for example, in the second partial stage, the valve or flap is more open than in the first partial stage. - a pump (for example, a vacuum pump) with adjustable flow rate. For example, in the first partial stage, the pump is not used, and in the second partial stage, the pump creates a flow from the container, or in the first partial stage, the flow rate is lower than in the second partial stage; - at least two valves or flaps, wherein, for example, a first valve or flap is opened for the first partial stage and a second valve or flap is opened for the second partial stage.

[0011] Of course, other options are possible.

[0012] In both the first and second partial stages, there is a reduction in pressure within the vessel, resulting in a pressure drop. In the first partial stage, this pressure drop is slower than in the second partial stage, so the steam explosion begins gradually but is still very effective. The advantage of this is that the recycled lignocellulose fragments are produced more gradually, yet efficiently, and the production of recycled lignocellulose fragments can be controlled more effectively. The result is also more uniform recycled lignocellulose fragments, more suitable for use in the production of new lignocellulose-based boards. The risk of recycled lignocellulose fragments being lost and / or blocking or polluting parts of the facility where the process takes place is also lower. To release the pressure from the vessel, an opening is needed through which the pressure can be released.By providing at least two partial steps, the risk of blockage of said opening and / or loss of fragments of... Petition 870250086477, dated 09 / 24 / 2025, page 11 / 56 The amount of recycled lignocellulose produced through this process is significantly reduced compared to a more abrupt pressure drop. This process makes it possible to produce recycled lignocellulose fragments efficiently.

[0013] The aforementioned recycled lignocellulose-based fragment can then be used as raw material in a process for the production of a new lignocellulose-based board. For example, if the recycled lignocellulose fragments are recycled wood fibers, they can be used for the production of a wood fiberboard, preferably for the production of an MDF or HDF panel.

[0014] With steam explosion, in addition to recycled lignocellulose fragments, a fraction of agglomerates and any other impurities can be produced. Preferably, the amount of agglomerates after steam explosion is less than 5% by weight, preferably less than 3% by weight, preferably less than 2% by weight, and even more preferably less than 1% by weight. Such embodiments confer even greater efficiency to the process. These embodiments can be achieved through a suitable choice of process parameters, preferably due to the fact that, in the first stage, the material is brought to temperatures above 10 bar, preferably 11 bar, and preferably 12 bar. If this is optionally affected by the use of saturated steam, an even greater energy efficiency of the process is obtained. Energy efficiency is expressed as the amount of energy required per mass of recycled lignocellulose fragments produced.

[0015] During the second stage, in which this material is kept under pressure and temperature for a certain period in the aforementioned container, a slight drop in pressure is possible. For example, the container may not be completely pressure-tight, so that Petition 870250086477, dated 09 / 24 / 2025, p. 12 / 56 6 / 31 a pressure drop is possible. With a smaller pressure drop, a pressure drop of less than 4 bar is indicated, preferably less than 3 bar, and a higher drop, preferably greater than 2 bar.

[0016] Recycled lignocellulose-based panels or boards are selected from end-of-life panels or boards. End-of-life panels or boards may include, but are not limited to: panels or boards that have been used by an end consumer and / or production waste and / or installation waste and / or transport waste and / or marketing waste and / or unsold stock. Recycled lignocellulose-based panels or boards are selected from a non-exhaustive list of: - wood fiber panels, such as HDF (high-density fiberboard), MDF (medium-density fiberboard), LDF (low-density fiberboard), softboard or hardboard; - particleboard, OSB (oriented strand board), plywood, glued laminated timber; - linen panels, hemp panels, bamboo panels; - board made of wood and plastic; - laminate comprising a lignocellulose-based substrate, such as wood fiberboard or particleboard, and, for example, one or more layers of resin-impregnated paper and / or a veneer layer; - Solid wood panels, engineered wood panels; - etc.

[0017] The refined material may have an average size, according to the figures, of less than 10 cubic centimeters, more preferably less than 5 cubic centimeters, more preferably less than 3 cubic centimeters.

[0018] The first and second ratios are average ratios, meaning that the pressure drop is the total pressure drop during the Petition 870250086477, dated 09 / 24 / 2025, page 13 / 56 7 / 31 The aforementioned partial stage and the duration is the total duration of the pressure drop in said partial stage. Preferably, during the entire time of said partial stage, there is a reduction in pressure such that the duration of the pressure drop in said partial stage is the total time of the duration of said partial stage. The instantaneous ratio between pressure drop and duration may or may not be constant during said partial stage. The instantaneous ratio is the ratio measured at time intervals smaller than the total duration of the pressure drop in a partial stage, being, for example, measured per second, or per half second, or per quarter second. Preferably, the maximum instantaneous ratio of the first partial stage is less than the maximum instantaneous ratio of the second partial stage. Preferably, the maximum instantaneous ratio of the pressure drop to the duration of the pressure reduction in the first partial stage is, at most, 1 bar / second.Pressure is normally released by opening the valve or flap. When opening this valve or flap to initiate the first partial stage, a high pressure is present, so a high maximum instantaneous rate may be present; however, it is preferable that, when opening this valve or flap, the instantaneous rate of pressure drop to the duration of the pressure reduction at the moment of opening said valve or flap is ensured to be less than 1 bar / second.

[0019] Preferably, the first ratio is at most 0.4 bar / second, preferably at most 0.2 bar / second, or preferably at most 0.1 bar / second. The first ratio can be 0.35 bar / second, 0.24 bar / second, or 0.13 bar / second. For example: - the pressure drop can be a maximum of 7 bar in the first partial stage and the duration of the pressure drop can be at least 20 seconds, so that the first ratio is a maximum of 0.35 bar / second; Petition 870250086477, dated 09 / 24 / 2025, page 14 / 56 8 / 31 - the pressure drop can be a maximum of 6 bar in the first partial stage and the duration of the pressure drop can be at least 25 seconds, so that the first ratio is a maximum of 0.24 bar / second; - The pressure drop can be a maximum of 4 bar in the first partial stage, and the duration of the pressure drop can be at least 30 seconds, so that the first ratio is a maximum of 0.13 bar / second.

[0020] In the first partial stage, the pressure reduction is preferably a maximum of 8 bar, and preferably a maximum of 7 bar. In the second partial stage, there may be a sufficient amount of pressure remaining, which will be reduced more rapidly, so that the steam explosion can occur sufficiently and recycled lignocellulose fragments of the desired quality are obtained.

[0021] In the first partial stage, the duration of the pressure reduction is preferably at least 10 seconds, preferably at least 20 seconds, for example, 30 seconds. Here, there is sufficient time to initiate the steam explosion gradually.

[0022] In a preferred embodiment, the second ratio is at least 0.25 bar / second, preferably at least 0.50 bar / second, and preferably at least 0.75 bar / second. This ensures that the pressure reduction is rapid enough to allow for good separation of the refined material into recycled lignocellulose fragments, with the lignocellulose fragments exhibiting good quality. The first ratio can be 0.33 bar / second, 0.6 bar / second, or 0.87 bar / second. For example, - the pressure drop can be at least 5 bar in the second partial stage and the duration of the pressure drop can be a maximum of 15 seconds, so that the second rate is at least 0.33 bar / second; Petition 870250086477, dated 09 / 24 / 2025, page 15 / 56 9 / 31 - the pressure drop can be at least 6 bar in the second partial stage and the duration of the pressure drop can be a maximum of 10 seconds, so that the second rate is at least 0.6 bar / second; - The pressure drop can be at least 7 bar in the second partial stage, and the duration of the pressure drop can be a maximum of 8 seconds, so that the second rate is at least 0.875 bar / second.

[0023] Preferably, the pressure drop in the first partial stage is at least 30% of the total pressure drop in the third stage, preferably at least 40%, preferably approximately 50%. This ensures a good balance between slow and rapid pressure release, so that good quality lignocellulose fragments are obtained efficiently. For example, the pressure drop in the first partial stage and the second partial stage can be approximately the same and, moreover, preferably there is only one first partial stage and one second partial stage, so that both the first and second partial stages account for approximately 50% of the total pressure drop. When, in the first stage, the material is brought to a pressure above 10 bar, preferably 11 bar, or preferably 12 bar, for example 14 bar, the pressure drop in the first and / or second partial stage can be, respectively, 4.5 bar, 5 bar, 5.5 bar or 6.5 bar.

[0024] In a highly preferred embodiment, the vessel comprises a pressure vessel and a first flap or valve for releasing pressure from the pressure vessel, such that preferably said first flap or valve makes a first tube connected to the pressure vessel closeable, so that in the first stage said first flap or valve is at least partially open to release pressure. This flap or valve can be opened gradually du Petition 870250086477, dated 09 / 24 / 2025, page 16 / 56 10 / 31 during the first stage, so that the instantaneous ratio between the pressure drop and the duration of the pressure drop is approximately constant during the first partial stage and / or does not exceed a certain maximum, for example, a maximum of 1 bar / second. This instantaneous ratio does not need to be constant. By gradually opening the valve or flap, the risk of recycled lignocellulose fragments blocking the valve or flap or the first tube is reduced. Preferably, the first tube is present and the pressure is released through the first tube. With the aid of this valve or flap and the optional first tube, water that could result from condensation during this process can also be easily discharged, so that lignocellulose fragments with the desired moisture content can be obtained.

[0025] Refined board or panel material made from recycled lignocellulose preferably has a moisture content of no more than 15% by weight, and preferably a moisture content of no more than 10% by weight.

[0026] The recycled lignocellulose fragments preferably have a moisture content of no more than 15% by weight, and preferably a moisture content of no more than 10% by weight, for example, 8% by weight, directly after the said steam explosion.

[0027] Furthermore, preferably, liquid water can be discharged through the aforementioned first flap or valve, and preferably the first flap or valve is connected to a lower part of the pressure vessel. This liquid water is then preferably discharged during the third stage and preferably at least during the first partial stage. This has the added advantage that the recycled lignocellulose fragments have a relatively low moisture content, for example, a moisture content of no more than 20% by weight, or, for example, a moisture content between 10 and 15% by weight. These Petition 870250086477, dated 09 / 24 / 2025, page 17 / 56 11 / 31 Recycled lignocellulose fragments, if they are recycled wood fibers, can be used directly in the production of wood fiber panels, without the need for an additional drying process. This implementation also has the advantage that the discharge of liquid water, formed mainly by condensation, increases the efficiency of the process.

[0028] Furthermore, preferably, the container comprises a second flap or valve, which preferably makes a second tube connected to the pressure vessel closeable, so that, in the second stage, said second flap or valve is at least partially opened to release the pressure. With the aid of a second flap or valve, said first and second partial stages can easily be obtained. Different embodiments are possible. Below, a non-exhaustive list of possibilities is presented: - First possibility: the first valve or flap is opened to start the first partial stage. Subsequently, the first valve or flap is closed to finish the first partial stage. When the first flap or valve is closed, the second valve or flap is opened to start the second partial stage, and then the second flap or valve is closed to finish the second partial stage. -Second possibility: the first valve is opened to start the first partial stage. Subsequently, the first valve is closed to finish the first partial stage. During the closing of the first valve, the second valve opens to start the second partial stage, and the second valve is closed to finish the second partial stage. Third possibility: the first valve or valves are opened to start the first partial stage. Subsequently, the second valve or valves are opened to start the second partial stage and finish the first partial stage. Then, the first valve or valve is closed. Petition 870250086477, dated 09 / 24 / 2025, page 18 / 56 12 / 31 The first valve or flap is closed, and subsequently or simultaneously, the second valve or flap is closed to complete the second partial stage. The closing of the first valve or flap can be done before or during the closing of the second valve or flap. Preferably, the first valve or flap is closed before the closing of the second valve or flap. In this way, the pressure in the pressure valve can be easily reduced by subjecting the second pipe to suction and / or vacuum, for example, by connecting the second pipe to an expansion vessel.

[0029] Naturally, if only a first valve or check flap is available, it is also possible to have the first and second partial step, controlling, for example, the amount of opening of the valve or check flap.

[0030] More preferably, the first valve is connected to the first pipe and the second valve is connected to the second pipe, provided that the diameter of the first pipe is smaller than the diameter of the second pipe. With the aid of a smaller first pipe, the pressure reduction in the first partial step can be sufficiently low, and with the aid of a larger second pipe, it can be ensured that the pressure reduction in the second partial step is sufficiently high. If the third possibility is used and / or an expansion vessel is connected to the second pipe and / or the amount of opening of the flaps or valves is controlled, different diameters of the first and second pipes may be optional, and this still with a first ratio smaller than the second ratio.

[0031] Also, preferably, the pressure vessel is positioned so that it has a lower side and an upper side, so that the first flap or valve is located closer to the lower side and the second flap or valve is located closer to the upper side. In this way, the first flap or valve is ideally positioned to also release liquid water and / or pressure. Petition 870250086477, dated 09 / 24 / 2025, page 19 / 56 13 / 31 more slowly, since the refined material will be located above and / or at the height of the first flap or valve. The second flap or valve is also ideally positioned to release pressure more quickly, since it will be located above the refined material and / or at the height of the higher refined material.

[0032] Also, preferably, the vessel comprises a grid that is positioned inside the pressure vessel and divides the pressure vessel into at least two distinct areas extending one over the other, a higher area above the grid where the refined material of recycled wood boards or panels is introduced and a lower area below the grid where the first valve or flap connects to the pressure vessel at the height of the lower area and, preferably, said second valve or flap (if present) connects to the pressure vessel at the height of the upper area. Said grid prevents the refined material from entering the second area and thus prevents the first flap or valve from being blocked during the third stage.The aforementioned grid forms a separation surface between the aforementioned upper and lower areas, and said surface may have a grid structure, i.e., openings, over approximately its entire surface and / or may have closed sections where no openings are present. The grid structure may have a consistent pattern, or different patterns are possible, with, for example, openings of different shapes and / or different distances between the openings. Preferably, the pressure vessel is designed so that the grid can be easily cleaned; for example, a steam inlet may be present at the height of the grid, so that when pressurizing the pressure vessel, the grid is also cleaned.

[0033] In addition, in a specific embodiment, a filter is present between the pressure vessel and said flap or valve. This filter may be designed as a grid or grate, so that the flow of Petition 870250086477, dated 09 / 24 / 2025, p. 20 / 56 14 / 31 air through said filter is sufficiently high. This filter will prevent fragments of recycled lignocellulose from passing through said valve or flap. The pressure vessel is preferably designed so that the filter can be easily cleaned and / or removed for cleaning or replacement.

[0034] In a specific embodiment, the said valve or flap is connected to an expansion vessel. With the aid of an expansion vessel, the pressure drop can be sufficiently rapid and / or can be efficiently controlled. For example, a pressure drop sufficiently rapid to approximately atmospheric pressure or below atmospheric pressure can be easily controlled with the aid of an expansion vessel. This expansion vessel can be connected to a pump, such as a vacuum pump, to actively reduce the pressure. With an expansion vessel, the pressure can be actively reduced. An additional advantage of using an expansion vessel is that if recycled lignocellulose fragments end up in the expansion vessel, they can be easily recovered.

[0035] The invention, according to a second aspect, relates to a process, optionally according to the first aspect of the invention, for the production of recycled lignocellulose fragments, such as recycled wood fibers or recycled wood chips, wherein the process comprises a group of sequential steps, and the process uses at least a first container and a second container, wherein said group of sequential steps occurs in the first container and wherein said group of sequential steps also occurs in the second container, wherein said group of sequential steps comprises at least - a first stage in which the refined material of boards or panels based on recycled lignocellulose - preferably MDF - is processed. Petition 870250086477, dated 09 / 24 / 2025, page 21 / 56 15 / 31 or recycled HDF - is introduced into the first container or, respectively, into the second container, and is moistened, heated and pressurized using steam; - an optional second stage in which this material is kept under pressure and temperature for a specified period of time in the first container or, respectively, in the second container; - a third stage of steam explosion of the wetted, heated and pressurized material, in which the pressure in the first container or, respectively, in the second container is reduced by at least 3 bar, and preferably by at least 5 bar, plus preferably by at least 7 bar; plus preferably by at least 10 bar, plus preferably by at least 11 bar; and in which recycled lignocellulose fragments are produced during said steam explosion; whereby, in order to reduce the pressure in the first container or respectively in the second container in the third stage, the steam is released from the first container or respectively from the second container and at least partially reused to pressurize the second container or respectively the first container, and this at the moment when the first stage occurs in the second container or respectively in the first container, so that the steam is partially reused.

[0036] The first and second stages of the first aspect are preferably the same as the first and second stages of the second aspect. The third stage of the first aspect may be the same as the third stage of the second aspect. However, the third stage of the second aspect may or may not be a multistage vapor explosion. If the third stage of the second aspect is a multistage vapor explosion, the characteristics and embodiments of Petition 870250086477, dated 09 / 24 / 2025, p. 22 / 56 16 / 31 The first aspect of the invention also applies to this second aspect of the invention. In the process according to the first aspect, the steam may or may not be at least partially reused to pressurize another container in which the steam explosion will occur.

[0037] The advantage of the second aspect is that the steam is partially reused, so less energy is needed to produce a certain amount of recycled lignocellulose fragments and steam consumption is reduced. The result is a more sustainable process.

[0038] The steam explosion is preferably a multi-stage steam explosion, meaning that the pressure reduction occurs in at least two partial stages; wherein the multi-stage steam explosion comprises at least a first partial stage in which the pressure in the vessel is reduced and a subsequent second partial stage in which the pressure in the vessel is further reduced, wherein partial reuse of the steam occurs in the first partial stage. Furthermore, preferably, a first ratio between the pressure drop in the first partial stage and the duration of the pressure reduction in the first partial stage is less than a second ratio between the pressure drop in the second partial stage and the duration of the pressure reduction in the second partial stage. As a result, the pressure reduction during the first partial stage will be slower and the steam can be reused fairly easily.For example, the first and second containers may each have a pressure vessel, wherein said pressure vessels are connected to each other by one or more pipes, which may be closed with the aid of one or more valves or flaps. The first partial stage of the third stage in the first container or, respectively, in the second container, may then occur by opening one or more valves. By opening one or more valves, the pressure vessels come into contact with each other and the pressure... Petition 870250086477, dated 09 / 24 / 2025, page 23 / 56 17 / 31 are in the pressure vessel of the first container or, respectively, in the pressure vessel of the second container, the pressure is reduced, while the pressure in the pressure vessel of the second container or, respectively, in the pressure vessel of the first container increases. Preferably, the pressure vessels have approximately the same dimensions and / or, preferably, the first partial step occurs until the pressure in the pressure vessel of the first container is approximately the same as the pressure in the pressure vessel of the second container.

[0039] Also, preferably, both the first and second vessels have at least one additional valve or flap, which preferably connects to an expansion vessel. For the first partial stage, preferably only the valves or flaps connecting the pressure vessels to each other are at least partially open. For the second partial stage, the said additional valve or flap is opened. The closing of said valves or flaps connecting the pressure vessels may be done before or simultaneously with the opening of said additional valve or flap.

[0040] Furthermore, in a preferred embodiment, in the first partial stage, the pressure is released until the pressure in the first and second containers differs by a maximum of 2 bar, preferably by a maximum of 1 bar, and is approximately the same. This allows for the recovery of a relatively large quantity of steam.

[0041] Preferably, a valve or flap is placed between the first and second containers to release the steam from one of the containers and reuse it in the other.

[0042] Each container is preferably connected to an expansion vessel to further reduce the pressure to, for example, atmospheric pressure or below atmospheric pressure.

[0043] In a preferred embodiment, in the first or second aspect, the container comprises a stirring mechanism, Petition 870250086477, dated 09 / 24 / 2025, page 24 / 56 18 / 31 where this agitation mechanism mixes the refined material in the vessel for at least part of the time period – and preferably for the entire time period – of the first and / or second stages. Furthermore, preferably, the vessel comprises a pressure vessel into which the refined material of recycled lignocellulose-based plates or panels is introduced, with the agitators located inside the pressure vessel. This embodiment has the advantage that the refined material is treated homogeneously in the vessel, which makes the process faster and more efficient, where the transformation into recycled lignocellulose fragments is more quickly and completely achieved. Instead of operating with an agitation mechanism to obtain good mixing, it is also possible to opt for operating with a vessel capable of rotating, for example, around a rotation axis.Of course, it is possible to choose to operate with a container that can rotate and has a stirring mechanism.

[0044] Furthermore, preferably, the vessel comprises a grid positioned within the pressure vessel and dividing the pressure vessel into at least two distinct areas extending one over the other: a higher area above the grid, where the refined material of recycled wood-based boards or panels is introduced, and a lower area below the grid, where one or more agitators are located in said higher area, and further, preferably, the grid comprises an opening that can be closed, where one or more agitators are preferably also provided to agitate after the steam explosion, so as to guide the recycled lignocellulose fragments through said opening and out of said pressure vessel.

[0045] Para a primeira etapa, o vapor é introduzido no recipiente, por exemplo, no vaso de pressão, se presente. O vapor pode ser in Petição 870250086477, de 24 / 09 / 2025, pág. 25 / 56 19 / 31 introduced in one or more locations. For example, the pressure vessel may be connected to one or more pipelines to introduce steam into the pressure vessel. Some of these pipelines may be located in a location where refined material and / or recycled lignocellulose fragments may accumulate. By introducing steam into such a location during the first stage, any accumulated refined material and / or recycled lignocellulose fragments are removed.

[0046] In a preferred embodiment in the first and / or second aspect, in the first stage, the material is brought to a pressure of at least 4 bar, preferably at least 6 bar, preferably at least 7 bar, for example, a pressure between 7 and 9 bar, such as 8 bar, preferably at least 10 bar, at least 11 bar or at least 12 bar. It has been shown that both high temperature and high pressure are favorable to the efficient production of recycled lignocellulose fragments. If the material is brought to a higher pressure, it is possible to implement a greater pressure drop during the third stage. A large pressure drop has proven to have a positive effect on process efficiency.In the case of a greater pressure drop, the material can be introduced more quickly and / or the material does not need to be kept under pressure for as long and / or the refined material used from recycled lignocellulose-based boards or panels may have lower homogeneity / quality. Lower homogeneity may, for example, indicate that there are many large pieces present in the refined material from recycled lignocellulose-based boards or panels. Lower quality may indicate that there are many impurities present, such as paper, metal, glass, plastic, etc. The material can be subjected to a pressure of, for example, 12 bar, 13 bar or 14 bar. Preferably, the refined material from recycled lignocellulose-based boards or panels is subjected to a pressure of no more than 20 bar. Petition 870250086477, dated 09 / 24 / 2025, p. 26 / 56 20 / 31 maximum 18 bar, so that no thermal damage occurs.

[0047] Preferably, for the first and / or second aspect, after the third stage, the recycled lignocellulose fragments have a moisture content between 3 and 20% by weight, preferably between 5 and 15% by weight, preferably between 10 and 15% by weight. The moisture content can therefore be between 10 and 13% by weight, for example, 11 or 12% by weight.

[0048] Preferably, for the first and / or second aspect, between 0.1 kg of steam and 1 kg of steam are consumed per kg of recycled lignocellulose fragments produced, even more preferably between 0.2 kg of steam and 0.7 kg of steam. For example, 0.4 kg, 0.5 kg or 0.6 kg of steam are consumed for the production of 1 kg of recycled lignocellulose fragments.

[0049] Preferably, for the first and / or second aspect, the time period from the beginning of the first stage to the beginning of the third stage is less than 5 minutes, preferably less than 3 minutes, preferably less than 2 minutes, preferably less than 90 seconds; and / or preferably more than 40 seconds, preferably more than at least 50 seconds. For example, this time is 60 seconds. These implementations have the advantage of achieving a high degree of process efficiency.

[0050] The duration of the first stage is a maximum of 60 seconds, for example, 50 seconds. This rapid heating stage ensures that condensate formation is limited and that optimal process efficiency is achieved, also and especially in terms of the energy required.

[0051] Preferably, for the first and / or second aspect, the third step is carried out in a time interval of less than 1 minute, preferably less than 45 seconds, or preferably less than 30 seconds. This third step can be carried out in a Petition 870250086477, dated 09 / 24 / 2025, page 27 / 56 21 / 31 time interval of at least 15 seconds, for example, at least 20 seconds. The time interval of the third stage may be, for example, 40 seconds. If the third stage comprises the first partial stage and the second partial stage, the time interval of the second partial stage is preferably shorter than the time interval of the first partial stage. For example, the first partial stage represents at least 60% of the total time interval of the third stage, preferably at least 70%, for example, approximately 75%. The second partial stage then represents at most 40% of the total time interval of the third stage, preferably at least 30%, for example, approximately 25%.

[0052] Preferably, for the first and / or second aspect, in the first stage, the refined material is heated to a temperature below 240 °C, preferably below 230 °C; and preferably above 130 °C, and preferably above 150 °C, preferably above 170 °C. Such temperatures are very suitable, as they allow the lignocellulose fragments to be released efficiently without the lignocellulose fragments themselves, such as wood fibers, being degraded, which would occur at higher temperatures, since cellulose has a degradation temperature of 260 °C.

[0053] Preferably, the time for the second stage is at least seconds, preferably at least 10 seconds.

[0054] It is possible to operate with two or more containers arranged in parallel. If there are two or more containers, the latter can, for example, be operated alternately in order to obtain continuity in the formation of recycled lignocellulose fragments.

[0055] After the third stage, the process may include the separation of lumps and any other impurities present besides the recycled lignocellulose fragments. This separation of Petition 870250086477, dated 09 / 24 / 2025, page 28 / 56 22 / 31 preference utilizes the mass difference between, on the one hand, the recycled lignocellulose fragments and, on the other hand, the lumps and any other impurities.

[0056] Naturally, this invention also relates to an installation that can be used for the processes according to the invention. An installation for the production of recycled lignocellulose fragments, such as recycled wood fibers or recycled wood chips, in which the processes according to the invention, for example, according to the preferred or specific embodiments of the invention, can be carried out. With respect to the installation, this typically refers to an installation comprising one or more vessels, as described above – for example, vessels with pressure vessels and valves or flaps – and, optionally, expansion vessels, piping, etc.

[0057] According to a third aspect, the invention relates to a process for producing a lignocellulose-based panel, preferably for producing an MDF or HDF panel, wherein the process comprises producing recycled lignocellulose fragments, as described in the first and / or second aspects of the invention, and wherein the process further comprises the step of supplying the recycled lignocellulose fragments as raw material in a production line - preferably in a dry production process - for the production of lignocellulose-based panels, preferably for the production of MDF or HDF panels.

[0058] In a preferred embodiment, panels made from recycled lignocellulose are chosen from: wood fiber panels, such as MDF or HDF panels, and laminates comprising wood fiber panel substrates. The recycled lignocellulose fragments are then recycled wood fibers. These fibers of Petition 870250086477, dated 09 / 24 / 2025, page 29 / 56 23 / 31 wood is then preferentially used for the manufacture of new MDF or HDF panels.

[0059] According to a first divergent variant, the present invention relates to a process for the production of recycled fibers, wherein the process comprises a first stage in which refined material from elements comprising recycled fibers is introduced into a container and moistened, heated and pressurized using steam; wherein the process optionally comprises a second stage in which this material is maintained under pressure and temperature for a specified period of time in said container, wherein the process comprises a third stage of steam explosion of the moistened, heated and pressurized material, wherein the pressure in the container is reduced by at least 3 bar, and preferably by at least 5 bar, preferably by at least 7 bar; preferably by at least 10 bar, preferably by at least 11 bar; and wherein recycled fibers are produced during the steam explosion; wherein the steam explosion is a multistage steam explosion, meaning that the pressure reduction occurs in at least two partial stages, wherein the multistage steam explosion comprises at least a first partial stage in which the pressure in the vessel is reduced and a subsequent second partial stage in which the pressure in the vessel is further reduced, wherein a first ratio between the pressure drop in the first partial stage and the duration of the pressure reduction in the first partial stage is less than a second ratio between the pressure drop in the second partial stage and the duration of the pressure reduction in the second partial stage.

[0060] According to a second divergent variant, the present invention relates to a process for the production of recycled fibers Petition 870250086477, dated 09 / 24 / 2025, page 30 / 56 24 / 31 of the process, wherein the process comprises a group of sequential steps, and the process makes use of at least one first container and one second container, wherein said group of sequential steps occurs in the first container and wherein said group of sequential steps also occurs in the second container, wherein said group of sequential steps comprises at least - a first stage in which the refined material, made from elements comprising recycled fibers, is introduced into the first container or, respectively, the second container, and is moistened, heated, and pressurized using steam; - optionally, a second stage in which this material is kept under pressure and temperature for a specified period of time in the first container or, respectively, in the second container, - a third stage of steam explosion of the wetted, heated and pressurized material, in which the pressure in the first container or, respectively, in the second container is reduced by at least 3 bar, and preferably by at least 5 bar, or preferably by at least 7 bar; more preferably by at least 10 bar, most preferably by at least 11 bar; and in which recycled lignocellulose fragments are produced during the steam explosion; wherein, in order to reduce the pressure in the first container or, respectively, in the second container in the third stage, the steam is released from the first container or, respectively, from the second container and, at least partially, reused to pressurize the second container or, respectively, the first container, and this at the moment when the first stage occurs in the second container or, respectively, in the first container, so that the steam is partially reused. Petition 870250086477, dated 09 / 24 / 2025, page 31 / 56 25 / 31

[0061] These elements comprising fibers for the first and second divergent variants may be, for example: insulating material, panels comprising vegetable fibers, such as flax fiber panels, linen fiber panels, hemp fiber panels, bamboo fiber panels. In this case, these fibers are, for example, flax fibers, hemp fibers, bamboo fibers. All embodiments described above for the process, as described for the first aspect, respectively for the second aspect according to the invention, apply mutatis mutandis to the first divergent variant, respectively to the second divergent variant.

[0062] In order to provide a better illustration of the features of the invention, the following text describes a number of preferred embodiments by way of example, without any limiting character, with reference to the accompanying drawings, in which: Figure 1 illustrates part of an installation that can be used in a first embodiment of the process according to the invention for the production of recycled wood fibers; Figure 2 shows a pressure vessel that can be used in embodiments of the invention and the positions of possible piping and valves; Figure 3 illustrates a grid that can be installed on the pressure vessel; Figure 4 illustrates part of an installation that can be used in a second embodiment of the process according to the invention for the production of recycled wood fibers; Figure 5 illustrates part of an installation that can be used in a third embodiment of the process according to the invention for the production of recycled wood fibers.

[0063] The facilities are used for a recycled wood fiber production process 10. Naturally, they can also Petition 870250086477, dated 09 / 24 / 2025, page 32 / 56 26 / 31 to be used to produce other lignocellulose fragments. The process comprises a first stage in which refined material 1, derived from MDF, HDF or laminate comprising recycled HDF / MDF, is introduced into a container and moistened, heated and pressurized with steam; wherein the process comprises a second stage in which this material is maintained under pressure and temperature for a certain period of time in said container; wherein the process comprises a third stage of steam explosion of the moistened, heated and pressurized material, in which the pressure in the container is reduced by at least 3 bar, and preferably by at least 5 bar, more preferably by at least 7 bar; more preferably by at least 10 bar, more preferably by at least 11 bar; and in which recycled wood fibers 10 are produced during the steam explosion.Furthermore, the aforementioned steam explosion is a multi-stage steam explosion with two partial stages, meaning that the pressure reduction occurs in two partial stages.

[0064] Figure 1 illustrates part of an installation that can be used in a first embodiment of the process according to the invention for the production of recycled wood fibers 10. Here, the process uses at least one vessel, wherein this vessel comprises a pressure vessel 2, piping 4a, 4b, 11 connected to said pressure vessel 2, and valves 3a, 3b, 13 that ensure that said piping 4a, 4b, 11 can be closed and opened as desired. Inside said pressure vessel 2, there is a grid 5 that divides said pressure vessel 2 into a higher area 6a above the grid 5, into which the refined material 1 is introduced, and a lower area 6b below the grid 5. The vessel further comprises an agitation mechanism 8 comprising agitators that are located and operate within said higher area 6a. The vessel Petition 870250086477, dated 09 / 24 / 2025, p. 33 / 56 27 / 31 comprises two steam inlet tubes 11, which are provided for injecting steam into pressure vessel 2 and which can be closed with the aid of valves 13. The higher steam inlet tube 11 is capable of rapidly filling pressure vessel 2 with steam, since the steam is injected into pressure vessel 2 in the higher area 6a, in a location where there is normally no refined material 1 present. The lower steam inlet 11 is provided for injecting steam at the height of grate 5 and above grate 5, therefore in the higher area 6a. By injecting steam with the lower steam inlet 11, not only can pressure vessel 2 be pressurized, but grate 5 can also be cleaned. Cleaning can occur in the first stage, but also before the first stage, so that pressure vessel 2 is cleaned before the introduction of refined material 1 in the higher area 6a.The container comprises a first tube 4a connecting the lower area 6b of pressure vessel 2 to a pump 12. A first valve 3a is provided to close and open the first tube 4a. The container comprises a second tube 4b connecting the upper area 6a of pressure vessel 2 to an expansion vessel 7, and this at a height above the refined material 1. Furthermore, the expansion vessel 7 connects via a third tube 4c to the first tube 4a, so that it is also connected to the pump 12. The third tube 4c can be closed by a valve 3c. In the first stage, refined material 1 is introduced into the upper area 6a, while all valves 3a, 3b, 3c and 13 are closed. For example, the introduction of refined material 1 may take between 10 and 20 seconds. Next, the valves 13 of the steam inlet pipes 11 are opened to inject steam into the pressure vessel 2 and pressurize it to a pressure of at least 11 bar.Next, the valves 13 of the steam inlet pipes 11 are closed. Steam injection may take between 40 and 60 seconds. In the second stage, the pressure vessel 2... Petition 870250086477, dated 09 / 24 / 2025, page 34 / 56 28 / 31 is maintained under pressure and temperature, for example, between 5 and 15 seconds. Then, in a third stage, a multi-stage steam explosion occurs with two partial stages. During this steam explosion, recycled wood fibers 10 are formed. Firstly, in a first partial stage of the third stage, valve 3a of the first tube 4a is opened and the pressure is slowly released to a pressure between 5 and 9 bar. During this first partial stage, water can be discharged through the first tube 4a. Then, in a second partial stage, valve 3b of the second tube 4b is opened and pump 12 draws air through the expansion vessel 7, so that the pressure drop is faster than in the first partial stage. Before or during the second partial stage, valve 3a of the first tube 4a may close. In the first partial stage of the third stage, the total pressure drop can be between 2 and 7 bar and can take between 20 and 40 seconds.The second partial stage of the third stage may have a total pressure drop of at least 5 bar and preferably between 6 and 10 bar, where the second partial stage may take between 5 and 15 seconds. Preferably, the first ratio between the total pressure drop and the total time in the first partial stage is less than the second ratio between the total pressure drop and the total time in the second partial stage. By having a slower pressure release in the first partial stage, it is ensured that the steam explosion is not too powerful, so that the quality of the recycled wood fibers is guaranteed.

[0065] Figure 2 shows a pressure vessel 2 and more possibilities for the steam inlet tubes 11. With the aid of more steam inlet tubes 11, it is possible to ensure that the pressure vessel 2 is not polluted with refined material 1 and / or recycled wood fibers 10 during the use of said pressure vessel 2.

[0066] Figure 3 shows a possible implementation of grid 5 Petition 870250086477, dated 09 / 24 / 2025, page 35 / 56 29 / 31 located inside pressure vessel 2 of Figure 1. This grid 5 may have a grid structure over its entire surface, but it may also have a grid structure only in certain locations (see Figure 3, where only half of the circular surface has a grid structure). This grid 5 also comprises an opening 9 that can be closed so that recycled wood fibers 10 can be released after the steam explosion.

[0067] Figure 4 illustrates part of an installation that can be used in a second embodiment of the process according to the invention for the production of a wood fiber panel. Here, the process uses at least two vessels, each of which comprises a pressure vessel 2, pipes 4a, 4b, 11 connected to said pressure vessel 2, and valves 3a, 3b, 13 that ensure that said pipes 4a, 4b, 11 can be opened and closed as desired. What makes this installation special is that the pressure vessels 2 are connected to each other by a first pipe 4a (see further below). Within each pressure vessel 2, there is a grid 5 that divides the pressure vessel 2 into a higher area 6a, above the grid 5, into which the refined material 1 is introduced, and a lower area 6b, below the grid 5. Each vessel further comprises an agitation mechanism 8, which comprises agitators located and operable within said higher area 6a.Each vessel comprises two steam inlet tubes 11, which are provided to inject steam into the pressure vessel 2 and which can be closed with the aid of valves 13. The higher steam inlet tube 11 is capable of rapidly filling the pressure vessel 2 with steam, since the steam is injected into the pressure vessel 2 at the highest area 6a, in a location where there is normally no refined material 1 present. The lower steam inlet tube 11 is provided to inject steam at the height of the grate 5 and, therefore... Petition 870250086477, dated 09 / 24 / 2025, page 36 / 56 30 / 31 both above grid 5, in the highest area 6a. By injecting steam through the steam inlet 11 located at the bottom, not only can pressure vessel 2 be pressurized, but grid 5 can also be cleaned. Cleaning can occur in the first stage, but also before it, so that pressure vessel 2 is cleaned before the introduction of refined material 1 into the upper area 6a. The first pipe 4a connects the lower areas 6b of the two pressure vessels 2 to each other. A first valve 3a is provided to close and open the first pipe 4a. Each vessel further comprises a second pipe 4b that connects the upper area 6a of each pressure vessel 2 to an expansion vessel 7, located at a height above the refined material 1. In addition, the expansion vessel 7 is connected, via a third pipe 4c, to a pump 12.In the first stage, refined material 1 is introduced into the upper area 6a of one of the pressure vessels 2, while all valves 3a, 3b, and 13 are closed. For example, this can take between 10 and 20 seconds. Then, valve 3a of the first tube 4a and valves 13 of the steam inlet tubes 11 of pressure vessel 2 are opened to inject steam into pressure vessel 2 and pressurize it to a pressure of at least 11 bar. The opening of valve 3a of the first tube 4a assists in pressurizing pressure vessel 2, as the first partial stage of the steam explosion occurs in the other pressure vessel 2 (see below). In the second stage, pressure vessel 2 is maintained under pressure and temperature, for example, between 5 and 15 seconds. Then, in the third stage, a multi-stage steam explosion occurs with two partial stages. During this steam explosion, recycled wood fibers 10 are formed.Firstly, in the first partial stage of the third stage, valve 3a of the first tube 4a is opened and the pressure is slowly released to a pressure between 5 and 9 bar. By opening valve 3a of the first tube 4a, the other pressure vessel 2 can be pressurized. Petition 870250086477, dated 09 / 24 / 2025, page 37 / 56 31 / 31 and part of the steam is reused. During this first partial stage, water can be discharged from the first tube 4a. Then, for the second partial stage, valve 3a of the first tube 4a is closed and valve 3b of the second tube 4b is opened, and pump 12 draws air through expansion vessel 7, so that the pressure drop is faster than in the first partial stage. In the first partial stage of the third stage, the total pressure drop can be between 2 and 7 bar and can take between 20 and 40 seconds. The second partial stage of the third stage can have a total pressure drop of at least 5 bar and preferably between 6 and 10 bar, where the second partial stage can take between 5 and 15 seconds. Preferably, a first ratio between the total pressure drop and the total time in the first partial stage is less than a second ratio between the total pressure drop and the total time in the second partial stage.By having a slower pressure release in the first partial stage, it is ensured that the steam explosion is not too powerful, thus guaranteeing the quality of the recycled wood fibers 10.

[0068] Figure 5 illustrates part of an installation that can be used in a third embodiment of the process according to the invention for the production of recycled wood fibers 10. Here, the process uses four containers and four expansion vessels 7, as described in the first embodiment. Here, all containers and expansion vessels 7 are connected to a pump 12.

[0069] The production of recycled wood fibers 10, as illustrated in the figures, is a batch process. Preferably, these batch processes are carried out in line with the continuous production of new wood fiber boards. Petition 870250086477, dated 09 / 24 / 2025, page 38 / 56

Claims

1 / 7 CLAIMS 1. Process for the production of recycled lignocellulose fragments (10), such as recycled wood fibers or recycled wood chips, wherein the process comprises a first step in which the refined material (1) of recycled lignocellulose-based boards or panels - preferably recycled MDF or HDF - is introduced into a container and moistened, heated and pressurized using steam; wherein the process optionally comprises a second step in which this material is maintained under pressure and temperature for a specified period of time in said container, wherein the process comprises a third step of steam explosion of the moistened, heated and pressurized material, wherein the pressure in the container is reduced by at least 3 bar, and preferably by at least 5 bar, more preferably by at least 7 bar; more preferably by at least 10 bar, more preferably by at least 11 bar;and in which recycled lignocellulose fragments (10), such as recycled wood fibers or recycled wood chips, are produced during said steam explosion; wherein the steam explosion is a multistage steam explosion, meaning that the pressure reduction occurs in at least two partial stages, characterized in that the multistage steam explosion comprises at least a first partial stage, in which the pressure in the vessel is reduced, and a subsequent second partial stage, in which the pressure in the vessel is further reduced, in which a first ratio of the pressure drop in the first partial stage to the duration of the pressure reduction in the first partial stage is less than a second ratio of the pressure drop in the second partial stage to the duration of the pressure reduction in the second partial stage.

2. Process, according to claim 1, characterized in that the first ratio is at most 0.4 bar / second, preferably at most 0.2 bar / second, more preferably at most 0.1 bar / second.

3. Process, according to claim 1 or 2, characterized in that in the first partial stage, the pressure reduction is at most 8 bar, preferably at most 7 bar and / or in that the duration of the pressure reduction in the first partial stage is at least 10 seconds, preferably at least 20 seconds.

4. A process, according to any of the preceding claims, characterized in that, during the first partial stage, the ratio between the pressure drop and the duration of the pressure reduction is approximately constant or not, wherein the maximum ratio between the pressure drop and the duration of the pressure reduction in the first partial stage is at most 1 bar / second.

5. A process, according to any of the preceding claims, characterized in that the second rate is at least 0.25 bar / second, preferably at least 0.50 bar / second, most preferably at least 0.75 bar / second.

6. A process, according to any of the preceding claims, characterized in that the pressure drop in the first partial stage is at least 30 percent of the total pressure drop in the third stage, preferably at least 40 percent, more preferably approximately 50 percent.

7. Process, according to any of the preceding claims, characterized in that the container comprises a pressure vessel (2) and a first flap or valve (3a) for releasing pressure from the pressure vessel (2), wherein preferably said first flap or valve (3a) makes a first tube (4a) connected to the pressure vessel (2) closeable, wherein in the first step said first flap or valve (3a) is at least partially opened to release pressure.

8. Process according to claim 7, characterized in that liquid water can be discharged through said first flap or valve (3a), and wherein preferably the first flap or valve (3a) is connected to a lower part of the pressure vessel (2).

9. Process, according to any one of claims 7 and 8, characterized in that the container comprises a second flap or valve (3b), which preferably makes a second tube (4b) connected to the pressure vessel (2) closeable, wherein in the second stage said second flap or valve (3b) is at least partially opened to release the pressure.

10. Process according to claim 9, characterized in that the diameter of the first tube (4a) is smaller than the diameter of the second tube (4b).

11. Process, according to any one of claims 7 to 10, characterized in that the pressure vessel (2) is positioned in such a way that it has a lower side and an upper side, wherein the first flap or valve (3a) is located closer to the lower side and the second flap valve (3b) is located closer to the upper side.

12. Process, according to any one of claims 7 to 11, characterized in that the vessel comprises a grid (5) that is positioned inside the pressure vessel (2) and divides the pressure vessel (2) into at least two distinct areas extending one over the other, a higher area (6a) Petition 870250086477, dated 24 / 09 / 2025, page 41 / 56 4 / 7 above the grid (5) wherein the refined material (1) from recycled wood boards or panels is introduced, and a lower area (6b) below the grid (5) wherein the first valve or flap (3a) connects to the pressure vessel (2) at the height of the lower area (6b).

13. Process, according to any one of claims 7 to 12, characterized in that between the pressure vessel (2) and a said valve or flap (3a, 3b), a filter is present.

14. Process, according to any one of claims 7 to 13, characterized in that a said valve or flap (3a, 3b) is connected to an expansion vessel (7).

15. Process, optionally according to any one of claims 1 to 14, for the production of recycled lignocellulose fragments (10), such as recycled wood fibers or recycled wood chips, wherein the process comprises a group of sequential steps, and the process makes use of at least a first container and a second container, wherein said group of sequential steps occurs in the first container and wherein said group of sequential steps also occurs in the second container, wherein said group of sequential steps comprises at least - a first step in which the refined material (1) from recycled lignocellulose-based boards or panels, preferably recycled MDF or HDF - is introduced into the first container or, respectively, into the second container, and is moistened, heated and pressurized by steam;- an optional second stage in which this material is held under pressure and temperature for a specified period of time in the first container or, respectively, in the second container, - a third stage of vapor explosion of the wetted, heated and pressurized material Petition 870250086477, dated 24 / 09 / 2025, page 42 / 56 5 / 7, in which the pressure in the first container or respectively in the second container is reduced by at least 3 bar, and preferably by at least 5 bar, more preferably by at least 7 bar; more preferably by at least 10 bar, more preferably by at least 11 bar; and in which recycled lignocellulose fragments (10) are produced during said vapor explosion;characterized by the fact that, in order to reduce the pressure in the first container or, respectively, in the second container in the third stage, the steam is released from the first container or, respectively, from the second container and at least partially reused to pressurize the second container or, respectively, the first container, and this at the moment when the first stage occurs in the second container or, respectively, in the first container, so that the steam is partially reused.

16. Process, according to claim 15, characterized in that the steam explosion is a multi-stage steam explosion, meaning that the pressure reduction occurs in at least two partial stages; wherein the multi-stage steam explosion comprises at least a first partial stage in which the pressure in the vessel is reduced and a subsequent second partial stage in which the pressure in the vessel is further reduced, wherein partial reuse of the steam occurs in the first partial stage.

17. Process according to claim 16, characterized in that in the first partial step, the pressure is released until the pressure in the first and second containers differs by a maximum of 2 bar, preferably by a maximum of 1 bar, and is preferably approximately the same.

18. Process, according to any of the Petition 870250086477, dated 09 / 24 / 2025, p. 43 / 56 6 / 7 claims 15 to 17, characterized in that a flap or valve (3a) is disposed between the first and second container so as to release the vapor from one of the containers and reuse it in the other container.

19. Process, according to any of the preceding claims, characterized in that each container is further connected to an expansion vessel (7) to further reduce the pressure to, for example, atmospheric pressure.

20. Process, according to any of the preceding claims, characterized in that the vessel comprises a pressure vessel (2) into which refined material (1) derived from recycled lignocellulose-based boards or panels is introduced, wherein the vessel comprises an agitation mechanism (8), wherein this agitation mechanism (8) comprises one or more agitators located in said pressure vessel (2) for mixing the refined material (1) in the vessel for at least part of the time period - and preferably for the entire time period - of the first and / or second stage.

21. Process, according to claim 20, characterized in that the vessel comprises a grid (5) which is positioned inside the pressure vessel (2) and divides the pressure vessel (2) into at least two distinct areas extending one over the other, a higher area (6a) above the grid (5) wherein the refined material (1) of recycled wood boards or panels is introduced and a lower area (6b) below the grid (5), wherein one or more agitators are located in said higher area (6a), and wherein the grid (5) preferably comprises a closeable opening (9), wherein one or more agitators are preferably also provided to agitate after the steam explosion of the third stage, so as to guide the lignocellulose fragments. Petition 870250086477, dated 09 / 24 / 2025, p. 44 / 56 7 / 7 recycled through the said opening (9) and out of the said pressure vessel (2).

22. Process for the production of a lignocellulose-based panel, preferably for the production of an MDF or HDF panel, characterized in that the process comprises the production of recycled lignocellulose fragments (10), as defined in any of claims 1 to 21, and in that the process further comprises the step of supplying the recycled lignocellulose fragments (10) as raw material in a production line – preferably in a dry production process – for the production of lignocellulose-based panels, preferably for the production of MDF or HDF panels. Petition 870250086477, dated 09 / 24 / 2025, pp. 45 / 56

Images