Plant for processing fibrous material and operating method for the same

Abstract

Plant for processing fibrous material and operating method for the same, wherein steam is returned by means of a pump device (500) from a steam outlet (430) of a fiber separator (400) via a steam return line (600) to a refiner-fiber separator connecting line (700) in order to support the discharge of a fiberized fibrous material from a refiner (300) and / or the transport of the fiberized fibrous material via the refiner-fiber separator connecting line (700) to the fiber separator (400).

Description

[0001] The invention relates to a plant for processing fibrous material and to an operating method of a plant as described in this application.

[0002] Currently, in the processing of fibrous material, the fiber material is fiberized by a refiner and then discharged from the refiner with a large amount of steam. This high volume of steam at least assists the transport of the fiberized material, as a fiber-steam mixture, from the refiner to a fiber separator. The fiberized material can then be separated from the fiber-steam mixture by the fiber separator, and the steam can be discharged from the fiber separator via a steam outlet. Such a device is known, for example, from WO 2015 / 014451 A1.

[0003] The object of the invention is to create a plant for processing fibrous material which requires less energy for its operation, as well as an operating method for such a plant and a use of such a plant or such an operating method.

[0004] The invention provides a system for processing fiber material according to claim 1, an operating method according to claim 12, a use according to claim 14, and a use according to claim 15. Advantageous embodiments of the invention are described in the dependent claims.

[0005] The steam return line and the pump device located in the steam return loop allow steam from the fiber separator's steam outlet to be returned to the refiner connection point of the refiner-fiber separator connecting line. This enables, among other things, improved (e.g., energy-saving and / or resource-conserving) support for transporting the fiber material-steam mixture from the refiner, even in cases where little steam is generated in the refiner due to less frictional heat during the fiberization process.This applies, for example, to the recycling of medium-density fiberboard (MDF) as post-consumer waste fiber material. When MDF is used as raw material, the fiber material is not as densely packed in the process state before the refiner as it is with solid wood-based raw material or other wood-based raw material being fiberized for the first time. Consequently, less energy is required in an MDF recycling process for fiberizing the raw material compared to fiberizing material that has not been previously fiberized. Less energy consumption results in less frictional heat and therefore less steam in the refiner, which could otherwise be used to transport the fiber-steam mixture out of the refiner.Consequently, the steam returned to the refiner can at least support the transport of the fiber material from the refiner as a fiber material-steam mixture, and reduce or eliminate the need to generate fresh steam elsewhere and introduce it to transport the fiber material to the fiber separator.

[0006] Furthermore, by recirculating the steam from the fiber separator to the refiner, the amount of steam loss is kept to a minimum, and steam cleaning is only required for a smaller amount of steam or is even avoided entirely.

[0007] Thus, the system according to the invention requires less energy; for example, less energy is needed to generate additional fresh steam and / or less energy is needed for steam cleaning.

[0008] In contrast to plants for processing fiber material without a refiner, the use of a refiner leads to an improved dissolution effect and reduced evaporation, and allows for both a design for carrying out a wet process and a design for carrying out a dry process.

[0009] Optionally, the refiner connection point of the refiner-fiber separator connecting line can be located in or at least adjacent to the steam recirculation loop.

[0010] The refiner can, for example, include a grinding chamber located between the fiber material inlet and the refiner outlet, and a grinding mechanism arranged within the grinding chamber for grinding the received fiber material. The refiner can be integrated into the steam recirculation loop and may have a refiner steam inlet that communicates with the refiner's grinding chamber and is connected to the steam recirculation line. This allows the steam discharged from the fiber separator's steam outlet to be recirculated back to the refiner's grinding chamber via the steam recirculation line, thus aiding the discharge of the fiberized material from the refiner. This improves and simultaneously increases the efficiency of transporting the fiberized material, as a fiber-steam mixture, from the refiner to the refiner-fiber separator connecting line and onward to the fiber separator.

[0011] The pump device can be integrated into the refiner, making the system more compact.

[0012] The grinding mechanism can include a grinding element rotatable around a grinding axis, or optionally a grinding disc rotatable around the same axis, which also serves as the rotatable impeller of the pumping device. By designing the grinding element as a rotatable impeller, it can perform a dual function, resulting in an even more compact design. Simultaneously, less energy is required because no additional part needs to be moved for pumping; instead, the rotating grinding element is enabled to also perform a pumping function by its design as a rotatable impeller.

[0013] The grinding element can have a grinding side, which has a grinding surface designed for grinding the fibrous material, and a pumping side opposite the grinding side, which is equipped with projections suitable for pumping, optionally with pump vanes. This separation of the grinding and pumping sides achieves a pumping effect through the pumping projections on the pumping side, without impairing the grinding process by reducing the grinding surface.

[0014] The grinding unit can have a further (or additional), optionally a stationary, grinding element, which is arranged opposite the rotatable grinding element, so that a grinding gap is formed between them, defining a grinding gap plane. The refiner steam inlet is located in or adjacent to the grinding gap plane and is aligned parallel to the grinding gap plane and radially or tangentially to the grinding axis of rotation. Furthermore, the refiner steam inlet can optionally be oriented at an angle of 90° to the grinding axis of rotation. Such an arrangement of the refiner steam inlet with respect to the grinding axis of rotation and / or the grinding gap plane allows the resulting steam flow to at least reduce deposits or fouling in the grinding gap and / or on one or both grinding elements. This can increase the efficiency of the grinding process and reduce downtime for maintenance and / or cleaning of the refiner.

[0015] As an alternative to aligning the refiner steam inlet with the grinding gap plane, the refiner steam inlet can be aligned with respect to the grinding axis of rotation at an angle of 0° (e.g. collinear with the grinding axis of rotation) to less than 90° towards the pump side, which allows the pump side of the grinding element to be cleaned during operation of the system, thereby reducing deposits on it and consequently also reducing dead times for cleaning the refiner.

[0016] Optionally, a pump device can be located in the refiner's grinding chamber (for example, in the form of the rotatable impeller described above), or a pump device can be located outside the refiner's grinding chamber but within the steam recirculation loop (e.g., the steam recirculation line). Alternatively, both a pump device in the refiner's grinding chamber and another pump device outside the refiner but within the steam recirculation loop can be present. By providing both pump devices, the transport capacity via the fiber-steam mixture can be further increased, if required, without supplying additional live steam.

[0017] As an alternative to the refiner integrated into the steam recirculation loop, the steam recirculation line can be connected directly to the refiner-fiber separator connecting line, so that the steam recirculation loop does not run through the refiner's grinding chamber. The suction effect created by the recirculated steam can assist in removing the fiber-steam mixture generated in the refiner and introducing it into the refiner-fiber separator connecting line, where the fiber-steam mixture is then transported to the fiber separator.

[0018] Furthermore, the system can also include a cooker upstream of the refiner to soften the fiber material via steam pressure (e.g., by hydrolyzing post-consumer fiber material to be recycled) and an additional steam return line. This additional steam return line can communicate with the steam outlet of the fiber separator, and optionally, it can branch off from the steam return line in a section between the steam outlet of the fiber separator and the refiner. In addition, the additional steam return line can be connected to the cooker to return the steam discharged from the steam outlet of the fiber separator to the cooker.Furthermore, the cooker, refiner, fiber separator, refiner-fiber separator connecting line, steam recirculation loop, and further steam recirculation line can form a high-pressure section in which the operating pressure is higher than the operating pressure upstream of the cooker inlet and downstream of the fiber material outlet of the fiber separator. The fiber material outlet of the fiber separator can be suitable for creating a pressure seal between the high-pressure section and a region downstream of the fiber material outlet of the fiber separator. This can be achieved, for example, by a conical closure (e.g., by the conical closure as described in EP 24 211 454.4), a compression screw (e.g., a discharge screw), or a rotary valve (e.g., by the rotary valve as described in DE 28 16 931 A1).If a compression screw is used to seal the fiber material outlet of the fiber separator, a subsequent loosening device is helpful to loosen the fiber material compressed by the compression screw (e.g., to separate it). The high-pressure section between the cooker and the fiber separator allows steam to be recirculated, thus saving steam and energy.

[0019] As an alternative to the system with a high-pressure section from the cooker to the fiber separator, the system can also include a cooker upstream of the refiner to soften the fiber material via steam pressure (e.g., by hydrolysis of post-consumer fiber material to be recycled), a cooker-refiner connecting line connecting the cooker to the fiber material inlet of the refiner, and a pressure range discharge device located in the cooker-refiner connecting line.In this configuration, the cooker and a section of the cooker-refiner connecting line upstream of the pressure-area discharge unit can form a high-pressure section. In this section, the operating pressure is higher than in a section of the cooker-refiner connecting line between the pressure-area discharge unit and the refiner. Optionally, the operating pressure in the vapor recirculation loop can be higher than in the section of the cooker-refiner connecting line between the pressure-area discharge unit and the refiner. This configuration results in a smaller high-pressure section, which (compared to a system with a high-pressure section from the cooker to the fiber separator) allows for more flexible and simplified transport of the fiber material or the fiber-vapor mixture downstream of the high-pressure section.Thus, the structure in which the high-pressure section does not contain the refiner and the fiber separator can allow for a simpler and more energy-efficient plant structure.

[0020] Furthermore, the system can also include a pre-steaming unit for pre-steaming fibrous material, optionally wood material, which is installed upstream of the digester to supply pre-steamed fibrous material to the digester. The pre-steaming unit is not part of the high-pressure section. A pre-steaming unit can pre-steam fibrous material without pressure at a slightly elevated temperature (e.g., above 20°C and up to 100°C) to soften the fibrous material and facilitate its fiberization and transport.

[0021] Furthermore, the system can include a pulper connected to the fiber separator to receive fiber material discharged by the fiber separator and disperse this fiber material in a liquid, optionally water. Using the pulper, the system can, for example, perform a wet process for processing fiber material.

[0022] In the inventive operating method for the inventive system, steam is returned from the steam outlet of the fiber separator via the steam return line to the refiner-fiber separator connecting line by means of the pump device in order to support the discharge of the fiberized fiber material from the refiner and / or the transport of the fiberized fiber material via the refiner-fiber separator connecting line to the fiber separator.

[0023] Furthermore, in this operating process, the fiber separator can be designed as a cyclone separator, whereby the recirculation of steam to the refiner-fiber separator connecting line by means of the pumping device accelerates the fiberized material to a velocity sufficient for the formation of a cyclone within the cyclone separator. Such an operating process can be lighter, more energy-efficient, more efficient, and simultaneously more environmentally friendly. This can be the case, for example, particularly in MDF board recycling and / or the production of lignocellulosic fibers for substrates.

[0024] The fiber material outlet of the fiber separator can optionally have a conical closure, a compression screw (e.g., a discharge screw), or a rotary valve. The fiber separator can be, for example, a cyclone separator (in which a flow cyclone can cause separation) or a centrifugal separator (in which separation can be caused by rotation of the fiber material-vapor mixture by means of a rotor device). The fiber separator can also be a cyclone separator with a rotary valve, as described in DE 28 16 931 A1.

[0025] The inventive plant and operating method can be used for recycling MDF boards, making it possible to recycle MDF boards more energy-efficiently and continuously.

[0026] Furthermore, the inventive system and the inventive operating process can be used to produce lignocellulosic fibers for substrate.

[0027] The invention is explained below with reference to exemplary embodiments and the accompanying drawings. These exemplary embodiments are not intended to limit the invention as claimed. Furthermore, the same reference numerals are used throughout all figures in the drawings for identical or similar features. The drawings show: Figure 1 a schematic representation of a plant for processing fibrous material according to an embodiment of the invention, Figure 2 a schematic representation of a plant for processing fibrous material according to another embodiment of the invention, and Figure 3a schematic representation of a plant for processing fibrous material according to yet another embodiment of the invention.

[0028] As in Figure 1 As shown, a system 1 according to an embodiment of the invention comprises a pre-steamer 100, a cooker 200, a refiner 300, a fiber separator 400, a pump device 500, a steam return line 600 and a refiner-fiber separator connecting line 700.

[0029] The pre-steaming unit 100 is equipped with at least one pre-steaming insert 101 to pre-steam fibrous material (e.g., wood material, e.g., wood fiber material). The pre-steaming unit 100 may include a pre-steaming transport screw 110, by means of which pre-steamed fibrous material can be transported towards the cooker 200.

[0030] The cooker 200 has a cooker inlet 210 (e.g., a rotary valve or a screw feeder). Furthermore, the cooker 200 can have a cooker pressure relief device 220 and a cooker transport screw 230. The cooker inlet 210 allows for pressure isolation between the pre-damping device 100 and the cooker 200 such that a higher pressure can be maintained in the cooker 100 compared to the pre-damping device 100. The cooker pressure relief device 220 is suitable for releasing pressure from the cooker 200 when the pressure in the cooker 200 exceeds a certain value, e.g., a value above which safe operation of the cooker is no longer possible. Furthermore, the Kocher pressure release device 220 can, for example, be set up to separate non-condensable gases and / or other gas components that are not water vapor in a controlled manner and to continuously feed them to a continuous exhaust gas treatment device.A continuous flue gas treatment system requires less space to process the same quantity of gas than a discontinuous flue gas treatment system. The cooker transport screw 230 transports fiber material within the cooker 200, for example, in such a way that the fiber material is transported towards the refiner 300 so that at the end of its passage through the cooker 200 it can be received by a fiber material inlet 310 of the refiner 300.

[0031] The refiner 300 also has a refiner outlet 320, a refiner steam inlet 330, a grinding chamber 340 with a grinding unit arranged therein (the grinding unit can have a grinding element 350 and another grinding element 360) and a refiner transport screw 370.

[0032] The refiner transport screw 370 can transport fiber material received via the fiber material inlet 310 of the refiner 300 in the direction of the grinding chamber 340 (e.g. to / into the grinding chamber 340).

[0033] The grinding element 350 and the additional grinding element 360 are positioned and configured in the grinding chamber 340 with an intervening grinding gap 355 to break down fibrous material in the grinding gap 355. Due to the friction that occurs, a fibrous material-vapor mixture is produced, which can be discharged from the refiner 300 via the refiner outlet 320. The grinding element 350 can be a rotatable grinding element, and the additional grinding element 360 can be a static grinding element. In particular, the additional grinding element 360 can be rigidly (e.g., integrally) connected to a refiner housing 380 of the refiner 300, which surrounds the grinding chamber 340. The grinding element 350 can be a grinding disc rotatable about a grinding axis M and have a grinding surface facing the additional grinding element 360.

[0034] The refiner fiber separator connecting line 700 is connected to the refiner outlet 320 at a refiner connection point 710 of the refiner fiber separator connecting line 700, and to the fiber separator at a fiber separator connection point 720 of the refiner fiber separator connecting line 700.

[0035] The fiber separator 400 has a mixing inlet 410, via which the fiber separator 400 is connected to the fiber separator connection point 720 of the refiner-fiber separator connecting line 700, so that the fiber separator 400 can receive fiber material-steam mixture via the mixing inlet 410, which originates from the grinding chamber 340 of the refiner 300 and is transported to the fiber separator 400 via the refiner-fiber separator connecting line 700.

[0036] Furthermore, the fiber separator 400 has a fiber material outlet 420 and a steam outlet 430. The fiber separator 400 is designed to separate fiber material from the fiber material-steam mixture and to discharge the separated fiber material from the fiber separator 400 via the fiber material outlet 420. The steam released in the fiber separator 400 is discharged from the fiber separator via the steam outlet 430 and from there, by means of the pumping device 500, is returned to the grinding chamber via the steam return line 600 and the refiner steam inlet 330.

[0037] Additionally, a further steam return line 800 can branch off from the steam return line 600 in a section between the steam outlet 430 of the fiber separator 400 and the refiner steam inlet 330 of the refiner 300, which is connected to the cooker 200 in such a way that a part of the steam discharged via the steam outlet 430 of the fiber separator 400 is returned to the cooker.

[0038] Furthermore, the fiber material outlet 420 of the fiber separator 400 is equipped with a conical closure 440. The operating pressure generated in the high-pressure section H, which includes the cooker 200, the refiner 300, the fiber separator 400, the refiner-fiber separator connecting line 700, the steam return line 600, the further steam return line 800, and the pump device 500, is higher than the operating pressure before the cooker inlet 210 and after the fiber material outlet 420.

[0039] The steam recirculation loop can run via the steam outlet 430 of the fiber separator 400, along a steam loop circuit direction (arrow A) via the steam recirculation line 600, the refiner steam inlet 330, the grinding chamber 340, the refiner outlet 320, the refiner connection point 710 to the refiner-fiber separator connecting line 700, whereby a further (or additional) steam recirculation loop is formed starting from the steam outlet 430 of the fiber separator 400, which then branches off from a section of the steam recirculation loop between steam outlet 430 and refiner steam inlet 330 from the steam recirculation line 600 and via the further steam recirculation line 800 to the cooker 200 and from there on to the refiner 300 and from there further to Refiner-fiber separator connecting line 700 runs.

[0040] The fiber separator 400 can be designed as a cyclone separator, whereby the fiberized material is accelerated to a speed sufficient to form a cyclone in the cyclone separator by means of the return of the steam to the refiner-fiber separator connecting line 700 by means of the pump device 500 (which can be, for example, a blower or a compressor).

[0041] Furthermore, the system 1 comprises a collection device 900, a collection device-dryer connection line 901, and a dryer 950. The collection device 900 is designed to collect the separated fiber material discharged via the fiber material outlet 420, which is then transported to the dryer 950 via the collection device-dryer connection line 901. For example, the fiber material can be transported to the dryer 950 by means of a blower 902 arranged in the collection device-dryer connection line 901. The fiber material can be further dried in the dryer 950. From the dryer 950, the fiber material can be transported via a processing line 951 to a further processing stage, for example, to the production of MDF boards.

[0042] A classifier for removing foreign matter can be arranged in the collection device-dryer connecting line 901 and / or in the processing line 951. For example, a classifier arranged in the collection device-dryer connecting line 901 can be a coarse classifier for removing coarse foreign matter, and the classifier arranged in the processing line 951 can be a classifier for removing less coarse foreign matter.

[0043] In system 1, the grinding element 350 can have a grinding side 351 designed for grinding the fibrous material and a pumping side (or pumping side) 352 opposite the grinding side 351. The refiner steam inlet 330 can be oriented at an angle of 0° to less than 90° with respect to the grinding axis of rotation M towards the pumping side 352 of the grinding element 350. For example, the refiner steam inlet 330 can also be aligned with respect to the grinding axis M on the pump side 352 at an angle of 0° to 80°, 0° to 70°, 0° to 60°, 0° to 50°, 0° to 45°, 0° to 40°, 0° to 30°, 0° to 20°, 0° to 10°, 10° to 80°, 10° to 70°, 10° to 60°, 10° to 45°, 10° to 30°, 30° to 60°, or 45°. For example, the refiner steam inlet 330 can also be aligned parallel or collinear with the grinding axis M on the pump side 352 of the grinding element 350.

[0044] For example, plant 1 can be used to perform a drying process for MDF board recycling (e.g., this further processing can include a pressing operation). Alternatively, plant 1 can be used to produce lignocellulosic fibers for substrate.

[0045] Figure 2 shows an attachment 1' according to another embodiment of the invention, which is similar to the one shown on the basis of Figure 1 The described Annex 1 is, whereby essentially only the differences are explained below.

[0046] In this embodiment, steam from the fiber separator 400 is returned to the refiner 300 via the steam outlet 430 by means of the pump device 500 and the steam return line 600 via the refiner steam inlet 330, however, there is no steam return from the fiber separator 400 to the cooker 200 via the further steam return line 800.

[0047] Furthermore, in the system 1', the refiner steam inlet 330 is arranged in or adjacent to the grinding gap plane E and parallel to the grinding gap plane E and aligned radially or tangentially to the grinding rotation axis M (see Figure 1 (regarding the position of M and E). For example, the refiner steam inlet 330 is arranged in the grinding gap plane E and oriented radially to the grinding axis of rotation M. For example, the refiner steam inlet 330 can be oriented at an angle of substantially 90° to the grinding axis of rotation M.

[0048] The steam recirculation loop can run via the steam outlet 430 of the fiber separator 400, along a steam loop circulation direction (arrow A) via the steam recirculation line 600, the refiner steam inlet 330, the grinding chamber 340, the refiner outlet 320, the refiner connection point 710 to the refiner fiber separator connecting line 700.

[0049] The fiber material discharged from the fiber material outlet 420 of the fiber separator 400 in system 1' can also be collected by the collection device 900, which may, for example, include a collection device transport screw 960. The fiber material from the collection device 900 in system 1' can be transported to a pulper 1000 by means of the collection device transport screw. The pulper 1000 can receive the fiber material and disperse it in a liquid (e.g., water). Furthermore, the pulper 1000 may include at least one dispersion device 1010.

[0050] The dispersed fiber material from the pulper 1000 can be transported further via a pulper processing line 1020, which may, for example, include a pump. The dispersed fiber material can then be transported via the pulper processing line 1020 for further processing into MDF boards (this further processing may, for example, involve a pressing operation).

[0051] For example, Plant 1' can be used to carry out a wet MDF board recycling process. Alternatively, Plant 1' can be used to produce lignocellulosic fibers for substrate.

[0052] Figure 3 shows an attachment 1" according to yet another embodiment of the invention, which is similar to the one shown on the basis of Figure 1 The described Annex 1 is, whereby essentially only the differences are explained below.

[0053] In this embodiment, steam from the fiber separator 400 is returned to the refiner 300 via the steam outlet 430 and the steam return line 600 via the refiner steam inlet 330, however, there is no steam return from the fiber separator 400 to the cooker 200 via the further steam return line 800.

[0054] The refiner steam inlet 330 can be configured either as shown in the Figure 1 embodiment shown or as in the Figure 2 as shown in the embodiment.

[0055] The grinding element 350 has, on its pump side 352, projections 500 suitable for pumping, which can be designed as pump vanes. The projections 500 are configured to achieve a pumping effect.

[0056] The pumping action generated by the 500 projections is suitable to replace the one in Figure 1 and 2 used separate pump device to function as a pump device.

[0057] However, in an embodiment not shown, a separate pumping device can be used in combination with protrusions on the grinding element suitable for pumping.

[0058] In the Figure 3 In the embodiment shown, the system 1" has a cooker-refiner connecting line 1100 which connects the cooker 200 to the fiber material inlet 310 of the refiner 300.

[0059] The cooker-refiner connecting line 1100 can have a pressure range discharge device 1101. For example, the pressure range discharge device 1101 can have a connecting line compression screw 1102 (e.g., a connecting line discharge plugging screw) and a counter-pressure device 1103 (e.g., in the form of a valve with a valve disc (in Fig. 3 schematically represented as an arrow)).

[0060] The cooker 200 and a section of the cooker-refiner connecting line 1100 can form a high-pressure section H upstream of the pressure range discharge device 1101, in which an operating pressure is greater than an operating pressure in a section of the cooker-refiner connecting line 1100 between the pressure range discharge device 1101 and the refiner 300.

[0061] For example, the high-pressure section H can run from the cooker inlet 210 to the pressure range discharge device 1101, wherein the operating pressure before the cooker inlet 210 and after the pressure range discharge device 1101 is lower than the operating pressure in the high-pressure section H bounded by the cooker inlet 210 and the pressure range discharge device 1101.

[0062] The counter-pressure device 1103 can seal the cooker-refiner connecting line towards the cooker 200 when the system 1 is started (e.g., be pre-tensioned in this direction) in order to separate the high-pressure section H from the following section. Additionally, the counter-pressure device 1103 of the pressure range discharge device 1101 can be configured to regulate the compression of the connecting line compression screw 1102 during operation.

[0063] The cooker-refiner connecting line 1100 can furthermore have a safety valve 1200 (e.g. a pressure relief valve) downstream of the pressure range discharge device 1101, wherein the safety valve 1200 prevents a high (e.g. impermissibly high) pressure increase in the section directly after the pressure range discharge device 1102 in the event of a malfunction of the pressure range discharge device 1102.

[0064] The in Figure 3The system shown in "1" can be connected to the fiber material outlet 420 in conjunction with both the Figure 1 explained facilities from the collection device 900 as well as those in connection with Figure 2 The facilities described above must be connected from the collection device 900 onwards.

[0065] Furthermore, the system 1" can be used, for example, to carry out a dry or wet MDF board recycling process. Alternatively, the system 1" can be used to produce lignocellulosic fibers for substrate. REFERENCE MARK LIST

[0066] 1, 1', 1" Fiber material processing plant 100 Pre-steamer unit 101 Pre-steamer insert 110 Pre-steamer transport screw 200 Cooker 210 Cooker inlet 220 Cooker pressure release device 230 Cooker transport screw 300 Refiner 310 Fiber material inlet 320 Refiner outlet 330 Refiner steam inlet 340 Grinding chamber 350 Grinding element 351 Grinding side 352 Pump side 355 Grinding gap 360 Additional grinding element 370 Refiner transport screw 380 Refiner housing 400 Fiber separator 410 Mixing inlet 420 Fiber material outlet 430 Steam outlet 440 Cone closure 500 Pump unit 600 Steam return line 700 Refiner-fiber separator connection line 710 Refiner connection point 720 Fiber separator connection point 800 Additional steam return line 900 Collection device 901 Collection device-dryer connection line 902 Blower 950 Dryer 951 Processing line 960 Collection device-screw conveyor 1000 Pulper 1010 Dispersing device 1020 Pulper-processing line1100 Boiler-refiner connecting line 1101 Pressure area discharge device 1102 Connecting line-compression screw 1103 Back pressure device 1200 Safety valve A Steam loop circuit direction E Grinding gap plane M Grinding axis of rotation H High pressure section

Claims

1. Plant for processing fiber material, comprising: - a refiner (300) which has a fiber material inlet (310) through which fiber material, optionally softened fiber material, can be received, and a refiner outlet (320) through which fiber material refined by the refiner (300) can be discharged as a fiber material-steam mixture, - a fiber separator (400) which is downstream of the refiner (300) and which has a mixing inlet (410) for receiving the fiber material-steam mixture, a fiber material outlet (420) for discharging fiber material separated by the fiber separator (400) from the fiber separator (400) and a steam outlet (430) through which steam from the fiber separator (400) can be discharged, - a refiner-fiber separator connecting line (700),which is connected to the refiner outlet (320) via a refiner connection point (710) and to the mixture inlet (410) via a fiber separator connection point (720), and through which the fiber material vapor mixture can be supplied from the refiner (300) to the fiber separator (400), and - a vapor return line (600) which is connected on one side to the vapor outlet (430) of the fiber separator (400) and on the other side to the refiner-fiber separator connecting line (700), so that a vapor return loop is formed, through which vapor discharged from the vapor outlet (430) of the fiber separator (400) can be returned along a vapor loop circulation direction (A) to the refiner-fiber separator connecting line (700), wherein the refiner connection point (710) is in or at least is arranged adjacent to the steam recirculation loop, and - a pump device (500) located in the steam recirculation loop, optionally in the steam recirculation line (600),is arranged and is set up to pump the steam recirculated via the steam recirculation loop along the steam loop circulation direction (A).

2. The system according to claim 1, wherein the refiner (300) has a grinding chamber (340) which is connected between the fiber material inlet (310) and the refiner outlet (320), and a grinding mechanism arranged in the grinding chamber (340) for grinding the received fiber material, and wherein the refiner (300) is integrated into the steam recirculation loop, wherein the refiner (300) has a refiner steam inlet (330) which communicates with the grinding chamber (340) of the refiner (300) and with which the steam recirculation line (600) is connected, so that the steam discharged via the steam outlet (430) of the fiber separator (400) can be recirculated via the steam recirculation line (600) to the grinding chamber (340) of the refiner (300) to facilitate the discharge of the fiberized material. to support from the refiner (300).

3. System according to claim 1 or 2, wherein the pump device (500) is integrated into the refiner (300).

4. System according to claim 3, wherein the grinding mechanism has a grinding element (350) rotatable about a grinding axis (M), optionally a grinding disc rotatable about the grinding axis (M), which is also designed as a rotatable pump impeller of the pump device (500).

5. System according to claim 4, wherein the grinding element (350) has a grinding side (351) which has a grinding surface designed for grinding the fibrous material, and a pumping side (352) opposite the grinding side (351) which is equipped with projections (500) suitable for pumping, optionally with pump vanes.

6. System according to claim 5, wherein the grinding mechanism has a further, optionally a stationary, grinding element (360) which is arranged opposite the rotatable grinding element (350) such that a grinding gap (355) is formed between them, which defines a grinding gap plane (E), and wherein the refiner steam inlet (330) is arranged in or adjacent to the grinding gap plane (E) and is aligned parallel to the grinding gap plane (E) and radially or tangentially to the grinding axis of rotation (M).

7. System according to claim 5, wherein the refiner steam inlet (330) is aligned with respect to the grinding axis (M) at an angle of 0° to less than 90° to the pump side (352).

8. A system according to any of the preceding claims, further comprising: - a boiler (200) upstream of the refiner (300) to soften the fiber material via steam pressure, - a further steam return line (800), -- which communicates with the steam outlet (430) of the fiber separator (400), wherein optionally the further steam return line (800) is branched off from the steam return line (600), optionally in a section between the steam outlet (430) of the fiber separator (400) and the refiner (300), and -- which is connected to the boiler (200) to also return the steam discharged from the steam outlet (430) of the fiber separator (400) to the boiler (200), wherein the boiler (200), the refiner (300), the fiber separator (400), the The refiner-fiber separator connecting line (700), the steam recirculation loop and the further steam recirculation line (800) form a high-pressure section (H) in which an operating pressure is higher,as an operating pressure before a cooker inlet (210) of the cooker (200) and after the fiber material outlet (420) of the fiber separator (400).

9. A system according to any one of claims 1 to 7, further comprising: - a cooker (200) upstream of the refiner (300) to soften the fiber material via steam pressure, - a cooker-refiner connecting line (1100) connecting the cooker (200) to the fiber material inlet (310) of the refiner (300), - a pressure range discharge device (1101) arranged in the cooker-refiner connecting line (1100), wherein the cooker (200) and a section of the cooker-refiner connecting line (1100) upstream of the pressure range discharge device (1101) form a high-pressure section (H) in which an operating pressure is greater than an operating pressure in a section of the cooker-refiner connecting line (1100) between the pressure range discharge device (1101) and the refiner (300),where optionally the operating pressure in the steam recirculation loop is greater than the operating pressure in the section of the cooker-refiner connecting line (1100) between the pressure range discharge device (1101) and the refiner (300).

10. System according to claim 8 or 9, further comprising - a pre-steaming device (100) for pre-steaming fibrous material, optionally wood material, which is connected upstream of the cooker (200) in order to supply pre-steamed fibrous material to the cooker (200), wherein the pre-steaming device (100) is not part of the high-pressure section (H).

11. Apparatus according to any of the preceding claims, further comprising - a pulper (1000) connected to the fiber separator (400) to receive fiber material discharged from the fiber separator (400) and to disperse this fiber material in a liquid, optionally in water.

12. Operating method for the plant according to any of the preceding claims, wherein steam is returned from the steam outlet (430) of the fiber separator (400) via the steam return line (600) to the refiner-fiber separator connecting line (700) by means of the pump device (500) to assist in the discharge of the fiberized fiber material from the refiner (300) and / or the transport of the fiberized fiber material via the refiner-fiber separator connecting line (700) to the fiber separator (400).

13. Operating method according to claim 12, wherein the fiber separator (400) is designed as a cyclone separator and wherein the fiberized material is accelerated to a speed sufficient to form a cyclone in the cyclone separator by means of the pump device (500) by returning the steam to the refiner-fiber separator connecting line (700).

14. Use of the plant according to any one of claims 1 to 11 or of the operating method according to claim 12 or 13 for recycling medium-density fiberboard.

15. Use of the plant according to any one of claims 1 to 11 or of the operating method according to claim 12 or 13 for producing lignocellulosic fibers for substrate.

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