BR112019012942B1 - METHOD FOR SEPARATING FIBERS - Google Patents

Abstract

METHOD FOR SEPARATING FIBERS The invention relates to a method for separating fibers using a container with a predefined reception volume, a vacuum pump, which is connected by a vacuum tube and a valve to the volume of the container, and a ventilation tube with a predefined transverse opening and at least one valve, wherein the valve can be switched, within a time interval of 19 ms to 41 ms, from a closed state to an open state and, within a time interval of 20 ms to 45 ms time from open state to open state. The method has at least the steps of filling the container with a predefined amount of water and at least one fiber composite, gas-tightly closing the container, mixing the water and the fiber composite by means of energy. mechanics, in particular through agitation, generate kinetic energy in the fiber composite by decreasing the internal pressure of the container to a value between -700 hPa to -950 hPa, and equalize the pressure inside the container to generate cavitation in the fiber composite. fibers, in which the equalization of pressure inside the container (...).

Description

[001] The present invention relates to a method for separating fibers, in particular a method for extracting fibers from a fiber composite or a fiber composite material by using cavitation. The method according to the present invention can be used in the field of the paper industry or in the recycling industry, for, for example, to recover the fibers contained in the composite materials of paper products (raw materials) and to be able to lead to the manufacture of paper or recycling. Furthermore, this can be used for other applications for fiber separation in different industries.

[002] Multiple use of fibers, for example from waste paper, preserves natural resources and is a key factor in protecting the environment, and also saves energy and water compared to the production of primary fiber paper in the manufacturing process and produces fewer harmful emissions and waste.

[003] Methods for recycling, in particular methods for separating fibers, are known in the art. The applicability of these methods essentially depends on the quality of the recycled fiber obtained and the use of resources, in particular energy expenditure, to carry out the method.

[004] In the manufacture of paper products, for example in the packaging materials sector, the percentage of composite materials and coated papers increases compared to used paper. Known examples here are composite packaging, such as beverage packaging, which consists of at least two materials, containing cardboard as the outer packaging layer and aluminum and/or a plastic layer as the inner packaging layer.

[005] These two materials are connected to each other so that separation is impossible with just your hands.

[006] The recycling of these packaging materials, but also of other paper products with an increasingly high content of composites, is possible by removing or separating the fibers (raw materials) contained therein, with methods known in the art. technique, almost impossible or possible only with very high energy expenditure.

[007] Typically, in methods known in the art, the used paper is moistened in a defibrator with water and soaked under mechanical action, so that the fibers swell and the material contained in the paper fibers separates. The shredders feature rotors for mixing, which increases internal material friction, resulting in better fiber separation.

[008] Document DE 10 2011 083 667 A1 discloses a method for wetting fiber material by means of a device, which comprises at least one housing having an opening that can be closed, as well as a rotor for mixing complete content of the accommodation.

[009] The methods known in the art have the disadvantage that a very long treatment time is required for immersion and swelling, for the separation of fiber composites or fiber composite materials. This causes waste separated from used paper and therefore fiber, such as plastic, aluminum foil, waxes, to be unnecessarily crushed, and only through additional process steps and at great cost and effort, fibers can be separated with great difficulty from the recycled fibers themselves. The amount of the recoverable fibers in this regard decreases significantly with the treatment time of the fiber composite and fiber composite materials. Furthermore, fibers can be crushed and/or damaged by internal material friction, thus reducing the yield and quality of recyclable fibers.

[0010] Furthermore, an excessively long treatment time has a negative effect on the fibers themselves and the associated constitution and on the strength properties of the fibers. Long fibers tend to break during a very long treatment time, resulting in reduced fiber quality. Furthermore, fibers are essentially altered in their shape, particle size and length by methods commonly employed in the prior art, resulting in reduced fiber quality and, consequently, a lower yield of recyclable fibers.

[0011] In order to counteract a reduction in fiber quality and the loss of recyclable fibers due to too long a treatment time, the fiber composite material is processed in the methods according to the prior art, in the defibrator only for one very short period of time. These methods have the disadvantage that a high percentage of the fiber composites or fiber composite material is not separated by the short treatment time and must be conveyed with the waste from further utilization/separation, to sorting and cleaning facilities arranged downstream. . This leads to a loss of high quality fibers and an increase in operating costs for the treatment/separation or final disposal of waste.

[0012] In this context, it is the objective of the invention to remedy, at least partially, the disadvantages of the prior art. This objective is solved by a method according to claim 1. Preferred embodiments of the invention are the subject of the dependent claims.

[0013] Therefore, the invention relates to a method for separating fibers, in particular to a method of extracting fibers from a fiber composite or a fiber composite material by means of cavitation with the use of at least one container with a predefined receiving volume, as well as at least one vacuum pump, which is connected via a vacuum tube and a valve to the container volume. In this case, fibers are understood to be a fine or thin structure similar to a thread that consists of a vegetable or animal raw material, through chemical and/or mechanical methods or that can also be produced synthetically. These fibers, in particular paper/cellulose fibers, represent the raw material for paper manufacturing and are associated with other materials, precisely in materials to be recycled into fiber composites or fiber composite materials. Fiber composites or fiber composite materials represent a strong bond between different materials. In this case, paper/cellulose fibers are used as part of a composite with other materials, for example, an aluminum coating, combined in such a way that they practically merge, forming a unit. Through the method of the invention, this unit/composite is separated by cavitation and both the paper/cellulose fibers and other composite materials are present separately. Cavitation is understood as a process based on the speed of decomposition of gas bubbles, in which gas bubbles in liquids are increased in volume after the generation of a pressure change, in particular when a vacuum is generated, and implode in the case of an explosive type pressure equalization. By imploding the gas bubbles, the increased volume of the gas bubbles is flooded with the liquid, whereby a kinetic energy acts on the fiber composite or fiber composite materials, and these are separated from each other. By explosive type pressure equalization is meant a rapid equalization of pressures between the pressure inside the container and the pressure outside the container within a range of 0.001 s to 1 s.

[0014] The method according to the invention stands out in particular for a cavitation method, with which preferably fiber/fiber bonds and fiber/non-fiber bonds, i.e. coatings of any type, are moved away or separated from each other. others. In particular, the non-fibrous compounds in the fibers (e.g. PE foil, aluminum foil, barrier coatings, etc.) are separated from each other practically fiber-free and over a large area, i.e. they are reduced or completely Residual adhesions of a percentage of residual fiber in these materials composed of an original fiber composite are avoided. Furthermore, fiber agglomerates or classical fibers/fiber composites are broken down into individual fibers. This decomposition also occurs in the case of special fiber compounds, which have been treated or impregnated, for example, with special agents (moisture resistant agents, resin, etc.) and which are not separable in the prior art or can only be separated through extremely high energy expenditure.

[0015] The method according to the invention is particularly designed to separate (pull apart) composite materials, which have been glued to a fiber fleece, coated (extruded), practically free of fibers and above all over a large area. This is done by this method in a preservative manner, without crushing the detached composite materials, as is already known from previous processes, unnecessarily. This property benefits the downstream sorting/separation of different materials to lead the different fractions that are thus formed respectively to a respective recycling circuit, and thus serves significantly for energy and resource efficiency.

[0016] Furthermore, with the method according to the invention, fiber composites can be dissolved, which are based on their altered properties (special pretreatment, e.g. hydrophobization) or very "tough" and are taken to the recycling process. This is not possible in the state of the art, nor with a high energy expenditure, or especially, for example, types of fiber or paper treated with moisture resistance.

[0017] The method of extracting fibers from a composite is advantageously carried out in a gas-tight sealable container, a so-called cavitation solvent. The container (cavitation defibrator) is sufficiently dimensioned in the choice of material, wall thickness and stiffening, so that it does not affect the execution of the process with the separation passes of individual fibers under different pressures through evacuation (expansion) or under explosive pressure equalization (implosion). The pressures necessary to produce the cavity are supplied through at least one conventional vacuum pump known in the art. The vacuum pump installed outside the container is connected directly to the container via at least one vacuum tube. To advantageously generate a vacuum and thus a depression, an additional pressure vessel is not necessary. This simplifies the structural design and reduces the volume of the entire system and leads to cost savings. At least one vacuum tube has at least one valve for closing and opening the vacuum tube. The vacuum tube valve is pneumatically controlled. Advantageously, by pneumatic control of the vacuum tube valve, it is possible to obtain a temporally oriented and coordinated sequence for generating the vacuum. Other control possibilities, such as, for example, electro-pneumatic control of the valves, are not ruled out with these measures.

[0018] Furthermore, at least one ventilation tube with a predefined transverse opening is used with at least one valve. The ventilation pipe valve has a closed state and an open state, wherein in the open state, air can pass through the valve and in the closed state, the valve is closed so that no air passes through the valve. The vent pipe valve can be switched from the closed state to the open state within a time range of 19 ms (milliseconds) to 41 ms. In this case, the valve is switched to the switching state in which air can pass through the valve. Furthermore, the ventilation pipe valve can be switched from open to closed state within a time interval of 20 ms to 45 ms. In this case, the valve is switched to the switching state, in which air cannot pass through it. The valve is preferably pneumatically controlled. Advantageously, a oriented and temporally coordinated sequence for generating the vacuum can be achieved by pneumatic actuation of the valves. Other control possibilities, such as, for example, electro-pneumatic control of the valves, are not ruled out with these measures.

[0019] The valves used (quick flaps) in the ventilation tubes are modified valves known in the art for opening and closing pressure and air tubes, respectively. Valves known in the prior art have the disadvantage of not reaching fast opening speeds to provide the cavitation necessary for the method of the invention. Only through high opening speeds is it guaranteed that the pressure in the internal compartment of the container to be evacuated is quickly compensated by the pressure outside the container. Modified valves feature an air chamber, a valve inlet, and a valve outlet, each connected to internally located guide tubes. Furthermore, the valve has an internal cylinder chamber, into which air is introduced through the valve inlet. In the inner cylinder chamber, a piston is rotatably mounted, which is in contact with the two guide tubes. The valve inlet and valve outlet have a diameter in the range of at least 1/4” (6.35 cm) to 3/4” (19.05 mm), preferably in the range of 1/2” (12, 7mm) to 3/4" (19.05mm), more preferably 3/4" (19.05mm). Through the modified design of the valve inlet or valve outlet, compared to prior art valves which feature a valve inlet of 1/4" or less, the piston is moved much more quickly, allowing air switching faster. Furthermore, the cylinder chambers have been modified in their volume and air outlet hole, which advantageously guarantees better air exit from the valve.

[0020] The method according to the invention presents at least steps i) to iv), which are described below. Furthermore, step iv) presents at least two additional substeps v) and vi).

[0021] The container (cavitation defibrator) is filled with a predefined amount of water and at least one fiber composite or fiber composite material. Alternatively, the container can already be filled with a water-fiber composite mixture, which has already been produced in a previous process step and another container made of a fiber composite or a fiber-water composite material. For filling, air supply and air extraction, as well as for emptying the container, it is preferably provided with five openings that can be closed in a gas-tight manner. These consist of a filling cap with a completely circumferential rubber seal for filling with fiber composites or fiber composite materials, and an emptying opening for removing recyclable fibers and for separating waste. Furthermore, the container has a dilution tube for supplying water and at least one vacuum tube with a valve. The vacuum tube is connected to at least one vacuum pump to establish an internal vessel pressure different from the pressure outside the tank (ambient vessel pressure). Furthermore, the container has at least one ventilation tube with at least one valve (quick flaps), wherein a pressure equalization between the internal pressure of the container and the ambient pressure of the container is carried out by opening the valve on the vent tube. ventilation. Through the rapid opening and closing of at least one valve in at least one ventilation pipe, explosive-type pressure equalization is carried out and, at the same time as providing vacuum through the vacuum pump, cavitation is generated between the composite fiber and fiber composite material. The fully circumferential rubber seal fill cap is a hydraulically and/or electrically actuated cap to close the container fill opening. The sequence of movement of the lid extends from an open position, which is not above the fill opening to be closed, to a closed position, which is above the fill opening to be closed. The fill cap moves from the open position to the closed position on wheels placed on the cap frame, which run on a straight guide mounted on the container. The filling cap is lifted before each crossing at the beginning of the movement sequence a few millimeters concurrently in the vertical direction so as not to advantageously damage the rubber seal placed on the lower side of the filling cap, slightly protruding and surrounding, by the friction of the filling process. fill cap, moving from the open position to the closed position or from the closed position to the open position. Traversing is understood as the sequence of movement of the lid from the open position to the closed position or from the closed position to the open position, with prior or subsequent raising or lowering in the vertical direction. The positioning state of the lid is detected by a sensor system that is selected from a group comprising electrical, magnetic, mechanical, electromechanical and/or optical sensors. On the front edge of the lid, a brush-type ruler is installed which, during the forward or backward movement of the lid, removes dirt found on the upper edge of the lid opening, to advantageously guarantee a complete sealing of the container by means of the fill cap. The front edge of the lid is understood to be the edge of the lid that has the shortest distance to the opening of the container when it moves from the open position to the closed position.

[0022] After filling the container with fiber composites or fiber composite materials, the container is gas-tight sealed so that no ambient air from the container can penetrate the container or through at least one vacuum pump can be established a pressure inside the container different from the pressure outside the container. By gas-tight closing the filling opening (filling cap) of the container, the first necessary vacuum (depression) is advantageously obtained to produce a corresponding cavitation by subsequent explosive-type pressure equalization.

[0023] After gas-tight closing of the container, mixing of water with the fiber composite or fiber composite material is carried out by using mechanical energy, in particular by stirring. Agitation is carried out by a stirrer installed in the container. By continuously stirring the pulp suspension by means of the stirring mechanism, the liquid distribution and thorough mixing of the pulp suspension are advantageously improved, thereby increasing the cavitation effect. Stirring is carried out at an average rotor speed controlled by a frequency converter in the range of 1 l/min to 1000 l/min, preferably in the range of 1 l/min to 500 l/min, more preferably in the range of 200 l/min to 500 l/min. Alternatively, for a better liquid distribution, a conventional rotor can be installed in the container, which can be driven by drives known in the state of the art, such as, for example, asynchronous motors with pulley and belt, or by means of gear or through direct drive with nominal breaking point in relation to the rotor axis. For gas-tight sealing of the rotor, a seal known in the art, for example a slip ring seal, is used.

[0024] By the method of the invention, a kinetic energy is generated in the fiber composites or fiber composite materials by two substeps (v) and (vi). Substeps (v) and (vi) are performed at least once, depending on the type and quantity of fiber composites to be processed and fiber quality required for further recycling, and may be repeated at least once and/or several times to increase both yield and fiber quality.

[0025] In a first substep (v), by evacuating the air out of the container through at least one vacuum tube, by means of at least one vacuum pump, an internal container pressure different from the pressure outside the container is established. container. The internal vessel pressure is reduced to a value between -700 hPa and -950 hPa. Through the depression generated in the container or by the generation of vacuum the gas bubbles present between the individual fibers of the water-immersed fiber composite or fiber composite materials are increased in volume. When these gas bubbles implode, within the fiber composite, between the fibers, as well as on adjacent surfaces, short-term extreme states with high pressure values and temperatures occur. Through these short-term extreme states within the fiber composites, even harder materials are attacked and corroded.

[0026] In the second sub-step (vi), a pressure equalization is generated in the container interior space to generate the above-mentioned cavitation in the fiber composite or fiber composite materials. Advantageously, a cavitation is generated by explosion-like pressure equalization by opening at least one valve in at least one vent pipe. Through cavitation, the gas bubble ruptures (implodes), causing the previously increased volume to be flooded with a liquid, preferably water. The kinetic energy of this space-occupying liquid results in collision energy in the form of liquid pressure, centrally conducting through the previously existing gas space. The resulting acicular energy bursts produce a "knock" of the fibers and tailings of fiber composites or fiber composite materials and thus result in a separation of the used material. The process of opening at least one valve in the ventilation pipe and quasi-explosive parallel pressure equalization occurs in a time interval of 0.001 s and 1 s. By generously opening the valve, the collapse of the gas bubble and the associated occurrence of kinetic energy within the fiber composite is further enhanced and the yield of recyclable fibers increases. Advantageously, through the increasingly available kinetic energy, the separation of fibers and waste is simplified and additionally accelerated, significantly reducing the treatment duration of the fiber composites or fiber composite materials as a whole and the fiber composites or composite materials fiber can be subjected to a significantly more preservative treatment for separation. This results in a better yield of recyclable fibers, as well as an improved quality of the recyclable fibers, as well as a significant reduction in the energy consumption of the method of the invention through the reduced treatment duration.

[0027] More specifically, in another embodiment, step (vi) preferably occurs within a time interval of 0.001 s to 0.1 s, more preferably within a time interval of 0.001 s to 0.01 s.

[0028] In one embodiment of the invention, the valve is connected via the vacuum tube with at least one non-return valve. Through the non-return valve, the valve and thus the vacuum tube are closed in one direction and released in the other opposite direction by the suction of the vacuum pump. When the vacuum pump is turned on, the sealing flap is lifted out of the flap seat and the gases and/or air present in the container are pumped out by the suction effect of the vacuum pump. When switching off the vacuum pump, the sealing flap is pressed against the flap seat by its own weight and thus closes tightly. Between the container environment and/or the vacuum tube with the vacuum pump and the inner space of the container in this regard, there will be no more air exchange and the vacuum within the inner space of the container and the pressure remain stable. The non-return valve structure described here represents only an exemplary description and is not limited to this technique. Likewise, valves with non-return elements containing, for example, spheres, cones and membranes, are used. The return mechanism or actuation of the closing element can also be carried out by means of a spring.

[0029] The presence of the non-return valve makes it possible to maintain the internal pressure of the container, in particular the depression, constant, in which, then, through the air that enters the flow in step (iv) cavitation is established between the fibers of the fiber composites or fiber composite materials. Through the non-return valve, it is possible to prevent the loss of vacuum through the vacuum tube when the vacuum in the container lasts for a long time. Furthermore, the non-return valve serves to protect the vacuum pump.

[0030] In another embodiment of the invention, the valves in the ventilation pipe are switched from the closed state to the open state in a time interval of 19 ms to 27 ms, preferably in a time interval of 19 ms to 24 ms and/or in a time interval of 20 ms to 39 ms, preferably in a time interval of 20 ms to 33 ms, more preferably in a time interval of 20 ms to 24 ms from the open state to the closed state.

[0031] The invention relates to a method for processing at least one fiber composite selected from a group of fibers containing natural fibers, such as vegetable fibers and/or mineral fibers and/or synthetic fibers, formed from polymers natural polymers of vegetable or animal origin, natural polymers and/or synthetic polymers and films of natural polymers and/or synthetic polymers and/or metal and mixtures thereof.

[0032] The invention also relates to a method in which, in addition to water and the fiber composite, at least one additional additive is added, which is selected from a group comprising acids, alkalis, dispersants, wetting agents and their combinations.

[0033] Furthermore, the invention relates to a method in which the fiber composite has been crushed before entering the container and preferably the individual parts of the fiber composite have an average maximum edge area of less than 10,000 mm2, preferably less of 100 mm2 and particularly preferably less than 25 mm2. It is advantageous that in this case a better penetration behavior of the liquid is achieved in the fiber composite, and thus by means of cavitation and disintegration of gas bubbles the penetrating liquid more effectively separates the fibers from the fiber composites or fiber composite materials. By reducing the edge area, there is an increase in attack surfaces and the prevention of overlapping parts, thus improving the yield and quality of the fiber through the process of the invention.

[0034] When using the method according to the invention for processing fibrous materials, the fibers used are less damaged. The fine branching of the fiber structure, particularly on the surface of the individual fibers, is less damaged than in prior art processes, which serve the same purpose, namely to enable pumping of the fibrous material and separation of the fibers.

[0035] In the filtrate of fibrous material dissolved by means of the described method, the chemical oxygen demand (CSB) to reduce the content present in the filtrate compared to prior art dissolution systems at the same degree of dissolution and with the same application material is reduced by 2 to 42%.

[0036] The drainage resistance according to Shopper-Riegler (°SR) is reduced by 1 to 8 points by using the described method in comparison with state-of-the-art dissolution systems with the same degree of dissolution and the same raw material .

[0037] As a result, among other things, an increase in the yield of the raw material used is obtained, a reduction in the drainage resistance of the fiber material thus produced and thus an increase in the production speed of the paper machine. Furthermore, there is a reduction in the need for contamination-reducing agents (biocides) and, therefore, a reduction in the burden on the environment. Reducing the overload of the wastewater treatment plant due to less load on the paper mill represents another advantage of the present invention.

[0038] In particular, the edge surface of the individual parts of the fiber composite increases substantially in proportion to the receiving volume of the container, which is thus reflected in a temporally constant process duration. A constant edge surface of the individual parts of the fiber composite in case of simultaneous increase of the receiving volume of the container can be reflected in a process extension.

[0039] In one embodiment of the invention, step (iv) is repeated in a predefined number of passes. By repeating step (iv), through the preservative treatment, an increase in fiber yield is obtained with an increase in fiber quality. For this purpose, the first pass of step (iv) proceeds under differential pressure with an action time of 2 minutes, in particular 3 minutes, in particular 5 minutes. Specifically, in the first pass of step (iv), the differential pressure (depression) generated by the evacuation of the container is maintained for the effective time, while the substance suspension is mixed (homogenized) under agitation by the rotor. Subsequently, by opening the valves in the ventilation pipes and thus obtaining rapid pressure equalization, cavitation is obtained between the fibers of the fiber composites or fiber composite materials. The gas bubbles between the fibers of fiber composites or fiber composite materials disintegrate and are filled with liquid, and a separation is made. Advantageously, fiber composites or fiber composite materials are prepared by the first pass with a longer action time, so that the method of the invention proceeds with a more preserving action for recyclable fibers. This leads to better fiber yield and fiber quality.

[0040] In another embodiment of the invention, step (iv) is repeated by varying the action time by at least another 4 passes, in particular by 9 additional passes, preferably in a range of 14 to 25 additional cycles, particularly preferably in 29 additional passes. By repeating step (iv) with the evacuation of the container and the generation of the differential pressure, as well as the subsequent rapid opening of the valve on at least one vent pipe, the yield of recyclable fibers, which have been separated from the fiber composite, is significantly increased.

[0041] In yet another embodiment of the invention, step (v) is completed in a first cycle in a time interval of 60 s to 120 s, in particular in a time interval of 80 s to 120 s, preferably in an interval of time from 100 s to 120 s, particularly preferably 120 s.

[0042] In one embodiment of the invention, the depression within the container after step (v) is a maximum of -950 hPa, especially a maximum of -700 hPa, preferably a maximum of -500 hPa. The level of depression to be adjusted results from the type, nature and quantity of the fiber composite or fiber composite material to be dissolved. The kinetic energy introduced from the water when imploding the gas bubble is greater when a higher depression is selected. This results through the resulting larger bubble volume with higher depression. Advantageously, by using a lower pressure to establish the depression, less energy is required, saving costs. In this regard, the depression level is chosen so that a positive relationship is established between the dissolution result and the fiber yield in a reasonable time and with low energy consumption. Depending on the fiber composite or fiber composite material, the combination of less depression with multiple passes of step (iv) or more depression in conjunction with fewer cycles of step (iv) may result in better fiber yield.

[0043] In one embodiment, the material filled in the container is composed of a suspension of substance, which consists of at least one liquid, which comprises water or water and at least one additional additive and a fiber composite with a percentage of solids, which are present in a ratio between liquid and percentage of solids in a range between 2% to 35%, preferably in a range between 5% to 25%, with particular preference in a range between 8% and 22%. The ratio of liquid to percentage solids was determined by methods in accordance with DIN 54 359. It was found to be advantageous that a good separation of reusable fibers from fiber composites or fiber composite materials is established at this liquid/percentage solids ratio. Advantageously, the generation of the cavitation process is improved at these material densities. At substance densities greater than the specified ranges, the suspension contains a very small proportion of water, which makes it difficult to carry out the cavitation process.

[0044] In another embodiment, after step (vi), the acceleration of the gas flowing into the container after opening the valve or valves in the cross section of the valve is between 20 m/s2 and 20,000 m/s2 , in particular between 2,000 m/s2 and 20,000 m/s2, preferably in a range between 6,000 m/s2 and 16,000 m/s2, particularly preferably in a range between 8,000 m/s2 and 16,000 m/s2 . Furthermore, the flow rate after step (vi) of the gas flowing into the container after opening the valve or valves in a range between 43 m/s to 1,000 m/s, in particular between 100 m/s to 750 m /s, preferably in a range between 200 m/s and 500 m/s, more preferably in a range between 300 m/s and 500 m/s. The disintegration of the gas bubble between the fibers of fiber composites or fiber composite materials is enhanced by the higher flow rates and optimizes the entire process. While slower flow velocities worsen, inhibit the process and therefore the disintegration of the gas bubble, these make cavitation unfeasible.

[0045] In one embodiment of the invention, the ratio between the container volume and the effective cross-sectional area of the vent tube or valves in the vent tube is in the range of 10,000 to 100,000, more preferably in the range of 35,000 to 75,000, preferably in a range of 50,000 to 60,000 more preferably in a range of 52,500 to 57,500. The ratio is determined by formula 1: Formula 1

[0046] Where:

[0047] Reason represents the relationship to be determined;

[0048] Vc represents the volume of the container;

[0049] N represents the number of valves connected through the ventilation tube;

[0050] Dv represents the diameter of the valves; It is

[0051] h represents the thickness of the valve closing flap.

[0052] The method according to the invention is based on cavitation. To create cavitation between the fibers in a fiber composite, the air in the container must first be evacuated with a predefined volume. In the next step, through at least one quick-acting valve in at least one vent pipe, air is applied to the substance suspension to produce disintegration of gas bubbles between the fibers in the fiber composites. In order to produce the positive effect of cavitation, the number of ventilation pipes to be provided with respective valves and their effective cross-sectional area depends on the volume of the container to be evacuated. Depending on the structure and size of the container, the number of ventilation pipes to be provided with corresponding valve is at least one piece. In particular, the relationship between the volume of the container and the effective area of the vent tube or valve indicates that the required rate of pressure equalization in the container, from the depression inside the container to the ambient pressure outside the container, occurs so quickly that it is made the decomposition of the gas bubble (cavitation) between the fibers of a fiber composite or fiber composite materials and these are separated.

[0053] The method according to the invention is also distinguished by the fact that, for example, contaminated fiber composites or non-fibrous fiber composites (e.g. used beverage boxes, coffee mugs, cups, etc.) and /or other types of mixtures in original fiber composites imply a reduction in microorganisms present in the application material during cavitation separation, which can be reduced by the method according to the invention. Thus, the total measured number of bacteria (molds, yeasts and bacteria) is reduced by 1 to 40%, which, among other things, is due to the improved separation and deposition of the different fractions. This results, among other things, in the advantages that the amount of consumption of microorganism-reducing agents (biocides) can be reduced and, thus, resulting in a reduction in burden on the environment. Additionally, there is a reduction in odor-causing ingredients from the dissolved fibrous material and a decrease in the load on the wastewater treatment plant.

[0054] The method according to the invention also offers the possibility of increasing the inherent strength and constitution of a vegetable fiber, that is, its strength properties by the cavitation process in the formation of sheet or fiber non-woven fabric.

[0055] This results in the advantages that a vegetable fiber treated by the cavitation process and thus separated undergoes stronger fibrillation. Through cavitation introduced into the fiber surface, the fibrils (keratinization) applied to the fiber wall in previous drying processes are suspended and the fibrils are reused for subsequent fiber bonding. This results, among other things, from the fact that the resistance properties (such as breaking load, tear length, breaking pressure, etc.) of a sheet produced from this fibrous material increase by 2 to 20% compared to a sheet made of fibrous material produced from the prior art of the same origin.

[0056] Finally, the method according to the invention shows that suitably pumpable vegetable fibers have a reduced swelling time. Tests showed that, for the same composition of fibrous material, it took less than three minutes compared to 20 minutes with state-of-the-art equipment technology. Downstream facilities for treating pumpable fibrous materials require less energy to achieve the same result.

[0057] This results, among other things, in the advantages that the reduced grinding resistance of the fibrous material is a saving of the energy to be used for refinery grinding by up to 15% and possibly also the need for chemicals in both the mass of fibrous material to be applied for sheet formation as well as in a subsequent surface finishing step may be lower than in the case of fibrous materials that have been processed by means of prior art equipment.

[0058] Another possibility, which the method according to the invention offers, is that, for example, during the cavitation process, vegetable fibers can be introduced into the dissolution process in order to give it additional or optimized properties. This results in the advantage that the vegetable fibers are conditioned in the process according to the invention; that is, depending on the constitution of the fiber, the structure of the fiber or the modifying substances belonging to the fiber of fibrous origin can be incorporated into the vegetable fiber. These additives can be, for example, coloring, hydrophobic, fluorescent or strength-increasing agents, or additives that can be provided with a nanoactuator or nanosensor.

[0059] In the following, various embodiments of the invention will be explained with reference to the drawings, which illustrate the invention by way of example only and do not limit the general teachings of the invention in terms of modifications. In which:

[0060] Figure 1 shows a flowchart to illustrate an embodiment of method 100 according to the invention.;

[0061] Figure 2 shows a schematic representation of an embodiment of the installation 200 with a cavitation defibrator 300 according to the invention;

[0062] Figure 3 shows a schematic representation of an embodiment of the cavitation defibrator 300 according to the invention;

[0063] Figure 4a is a schematic representation of an embodiment of the filling cap 330 of the cavitation defibrator 300 according to the invention in side view;

[0064] Figure 4b is a schematic representation of an embodiment of the filling cap 330 of the cavitation defibrator 300 according to the invention in top view;

[0065] Figure 5 shows a schematic representation of an embodiment of the valve 341 of the ventilation tube 340 of the cavitation defibrator 300 according to the invention;

[0066] Figure 6 shows a schematic representation of the opening speeds of the valve 341 of the ventilation tube 340;

[0067] Figure 7 is a schematic representation of the potential percentage savings in energy and cellulose separation time of the method of the invention in relation to methods known in the prior art.

[0068] Figure 1 shows a flowchart to illustrate a first embodiment of method 100 according to the invention. In particular, this first embodiment of method 100 is carried out by means of embodiments of the device shown in Figures 2 to 5.

[0069] Before filling the container 101 with a predefined amount of water and at least one fiber composite or fiber composite material, the seal water pump 240 is turned on to supply the seal water through the seal water pipe. seal 241 to the rotor slip ring seals 242 and the vacuum pump slip ring seal 243. The sealing water is supplied with at least a minimum pressure of six bars. With a sealing water pressure below the minimum pressure, the impeller and vacuum pump 220 are stuck and become inoperative. Furthermore, the slide (emptying) valve 320 is closed as an emptying opening for removing recyclable fibers and separating waste. For raising and lowering the filler cap 330, as well as for moving the filler cap 330 along the direction of movement 333, from the closed position 331 to the open position 332, the hydraulic unit 232 is connected. filling 330 is lifted in the vertical direction by a few millimeters and moved to the open position 332. Next, the main motor 210 is turned on, whereby the rotor rotates at the preset speed. The number of revolutions depends on the fiber composite or fiber composite material in a range from 1 l/min to 500 l/min. This embodiment refers to the use of an asynchronous motor 210 in combination with the belt 213/pulley 211, 212 or a motor/transmission configuration. In addition, valve 341 (fast flaps) in vent tube 340 is opened. The amount of water is adjusted via the inductive flow meter 251, where the material density required for the process lies in a liquid to solid ratio in a range between 2% and 35%, preferably in a range between 5% and 25%, particularly preferably in the range between 8% and 22%. Subsequently, the liquid (water) inlet is made through the open feedwater valve 252 and the addition of the fiber composite or fiber composite material, depending on the density of the material to be achieved through the shiftable fill cap and filling cap. closable gas-tight filling 330.

[0070] After filling the container 310, the filling cap 330 is closed in a gas-tight manner 102 and the hydraulic unit is turned off. During the gas-tight closing of the filling cap 330, a premix of the substance suspension is made by the rotating rotor.

[0071] After the gas-tight closure of the container 310, the step of mixing the suspension of substances 103 is carried out using mechanical energy, in particular by stirring by means of the rotor for a time of at least two minutes. After the preset mixing time, valve 341 of the vent pipe is closed.

[0072] After complete mixing of the suspension of substances, kinetic energy is generated in the fiber composite 104. For this purpose, the vacuum pump 220 is turned on to establish a differential pressure (depression) in the interior space of the container.

[0073] In substep (v) 105, with the use of the vacuum pump 220, a differential pressure (depression) is generated within the container 310 of at most -950 hPa, more preferably at most -700 hPa, preferably at -500 hPa. The level of the differential pressure dependent on the fiber composite or fiber composite materials to be dissolved and in this regard is specified at the beginning of method 100. The establishment and maintenance of the differential pressure (depression) is done in a first pass of step 104 , in total with an action time of 2 minutes, in particular 3 minutes, preferably 5 minutes. In this first pass, the suspension of substances is mixed and homogenized under agitation using the rotor, maintaining the differential pressure. By establishing and maintaining differential pressure, the volume of gas bubbles in the liquid increases. Through homogenization, the fibers of fiber composites or fiber composite materials absorb this liquid, in this embodiment of the invention, water.

[0074] Upon reaching the previously set differential pressure (depression) in the interior space of the container 310, the ventilation tube 340 is explosively opened and closed by the valve 341 in the ventilation tube 340. Through the rapid opening and closing of the valve 341 in the substep (vi) 106, an explosive-type pressure equalization occurs in the interior space of the container. Through explosive-type pressure equalization (vi) 106, the gas bubbles implode and the increased volume of the gas bubbles is flooded with water, whereby a kinetic energy acts on the fiber composite or fiber composite materials and separates them. each other's.

[0075] The differential pressure is determined by a pressure transducer 222 inside the container 310.

[0076] After the first explosive-type opening and closing of the valve 341 in the ventilation tube 340 within at least a time interval of 0.001 s and 1 s, preferably within 0.001 s and 0.1 s, more preferably within 0.001 s and 0 .01 s, and after the pressure equalization thus accomplished, the vacuum pump 220 generates a vacuum through the vacuum tube 221 and re-establishes a depression in the container 310.

[0077] Substeps (v) and (vi) are repeated under continuous operation of the vacuum pump 220 in at least four additional passes, in particular nine additional passes, preferably in a range of fourteen to twenty-five additional passes, particularly preferably in twenty-nine additional repeated passages. The number of additional passages of the valve 341 that opens and closes in the range of milliseconds in the ventilation tube 340 is adjusted at the beginning of the method 100 depending on the fiber composite or fiber composite material.

[0078] After the predefined cyclic sequence 107 has been completed, the vacuum pump 220 is turned off and the vent tube 340 is opened by opening the valve 341 in the vent tube 340, whereby a complete pressure equalization between the internal pressure and of the container and the ambient pressure of the container. Further, the hydraulic unit 232 is turned on and the filling cap 330 of the gas-tight closed container 310 is lifted in the vertical direction by a few millimeters and moved from the closed position 331 to the open position 332 along the direction of movement 333 After completion of the lid movement, the hydraulic unit 232 is turned off. Through the inductive flow meter 251, the amount of water for a subsequent dilution of the suspension of substances is adjusted and through the opening of the feed water valve 252 the adjusted water inlet is made. Subsequent stirring is carried out depending on the fiber composite or fiber composite material used in a subsequent stirring time of 0 to 3 minutes using an average rotor speed in the range of 1 l/min to 1,000 l/min , preferably in the range of 1 l/min to 500 l/min, more preferably in a range of 200 l/min to 500 l/min. After completion of the subsequent stirring process, the suspension is discharged through the slide valve (emptying slide valve) 320 and conveyed for further processing and/or recovery and/or disposal. To empty the container 310, if necessary, subsequent washing is carried out once again. After emptying the container 310, the main motor 210 and then the seal water pump 240 are turned off.

[0079] In a further embodiment, a direct driver, for example, a torque motor/direct motor is used as the main motor 210, in which first adding the water and the fiber composite or fiber composite material into the container 310 is done and then the main engine 210 and thus the rotor are turned on. Advantageously, additional energy savings can be obtained through this other modality.

[0080] Figure 2 shows the schematic two-dimensional representation of an embodiment of the installation 200 with a cavitation defibrator 300 according to the invention during the process sequence 100 with a closed fill cap 330. In this case, the fill cap 330 is above the filling opening of the container 310 in the closed position 331. Using the hydraulic unit (not shown), hydraulic pressure is provided, whereby the filling cap 330 is raised vertically by a few millimeters to the closed position 331 and then moves along the direction of movement 333 in the direction of the open position 332. During filling of the container with fiber composite or fiber composite materials, the filling cap 330 is in the open position 332. After the process is completed filling, the filling cap 330 is moved along the direction of movement 333 to the direction of the closed position 331 and deposited above the filling opening such that the container 310 is closed in a gas-tight manner. Furthermore, the installation 200 with cavitation shredder 300 features a main motor 210. The driving force of the main motor 210 is transmitted via two pulleys 211, 212 via a belt 213 to the rotor (not shown) situated within the container 310. The connection between the rotor and the pulley 212 is sealed via the slip ring seal 242. For this purpose, via the sealing water pump 240 through the sealing water pipe 241, the sealing water is supplied with a minimum pressure of 6 bar. Furthermore, through the sealing water pump 240 through the sealing water pipe 241, the slip ring seal 243 is supplied in the vacuum pump 220 with sealing water. Through the vacuum pump 221, air is sucked out of the interior space of the container by means of the vacuum pump 220 and thus a vacuum or a differential pressure (depression) is generated in the container 310. Through the pressure transducer 222, the pressure differential generated in container 230 is determined. Furthermore, the installation 200 with cavitation defibrator 300 has a feed water pipe 250, in which the amount of water required for the method 100 through the opening of the feed water valve 252 is supplied to the container 310. With the Using the inductive flow meter 251, the amount of water required for method 100 is adjusted depending on the consistency. Water is also led through the feed water pipe 250 for re-diluting the suspension of substances after step (iv). Furthermore, the installation 200 with cavitation defibrator 300 has a ventilation tube 340 with a valve 341 for pressure equalization after reaching the set differential pressure. By explosively venting the container 310 by rapidly closing the valve 341 on the vent pipe 340, cavitation is generated in the fiber composite or fiber composite materials.

[0081] Figure 3 shows a schematic representation of an embodiment of the cavitation defibrator 300 according to the invention of installation 200 in a side view. In this embodiment, the container 310 is shown open and the filler cap 330 is in the open position 332. The filler cap 330 moves along the direction of movement 333 from the open position to the closed position via wheels 371 (not shown) placed lid frame 334, which runs in a rectilinear guide 370 placed container 310. Before movement of the filler cap 330 along the direction of movement 333, the filler cap 330 is lifted in the vertical direction by a few millimeters to prevent advantageously that the slightly protruding and surrounding rubber seal 360 that engages the underside of the fill cap is damaged by process friction of the fill cap 330 along the direction of movement 333.

[0082] Figures 4a and 4b show a schematic representation of an embodiment of the filling cap 330 of the cavitation defibrator 300, according to the invention, in a side view and in a plan view. In this embodiment, the filler cap 330 is in the open position 332. The filler cap 330 is actuated through the actuator 350, which is installed in the cover structure 334, and moved from the closed position 331 to the open position 332 and from the open position 332 to the closed position 331, respectively. As a driver, a motor can be used from the group, containing electric motors, hydraulic or pneumatic motors. The driving force is transmitted by means of a belt, chain and/or gear to the wheels 371 that run in the rectilinear guide. Before moving the filler cap along the direction of movement 333, the filler cap 330 is lifted in the vertical direction by a few millimeters, advantageously so as not to damage the slightly protruding, surrounding rubber seal 360 that engages the underside of the filler cap. filling 330. Through the brush ruler 372 installed on the front side of the filling cover 330, dirt in the container cover opening 310 is removed along the movement direction 333 during the filling cover 330 process.

[0083] Figures 5a and 5b show examples of embodiments of modified valves 341 known in the state of the art, of the ventilation tube. Figures 5a and 5b show the double-acting valve 341, in particular Figure 5a shows the valve 341 closed and Figure 5b shows the valve 341 open. Through connection 342, valve 341 is activated with compressed air, whereby the compressed air flowing into the guide tube 344A is conducted to the inner chamber of the cylinder 346 through the orifice 345 in the guide tube 344A and the pistons 348 and the guide tubes 344A, 244B move apart from each other. This has the consequence that the central switching shaft 347 rotates 90° counterclockwise and the flap fixed there to the ventilation tube 340 also rotates through 90° and the ventilation tube 340 opens.

[0084] To close the valve 341, the connection 343 of the valve 341 is pressurized with compressed air and the compressed air flows through the guide tube 344B into the two external pressure chambers 349. The pistons 348 move toward each other. to the other and rotate the central commutation shaft 347 through the rack next to the piston 348 by 90° clockwise.

[0085] Figure 6 shows the opening and closing times of the modified valve 341 of the ventilation tube 340, determined in switching tests by a high-speed camera (1,000 images/s). For the generation of cavitation in fiber composites or fiber composite materials, it is necessary that, within a minimum time interval, a pressure equalization occurs between the internal pressure of the container and the ambient pressure of the container. In this regard, the switching times of the different embodiments of the valves in Figures 5a and 5b were recorded and evaluated under constant conditions to determine the fastest opening time. This shows, compared to the standard trigger (test 10), a significant improvement in opening time by 105 ms to 112 ms. Advantageously, the faster opening time improves cavitation in fiber composites or fiber composite materials and therefore the separation of fibers from waste, which reduces dissolution time. This reduces the cost of the fiber separation process from fiber composites.

[0086] Figure 7 shows the potential percentage savings of the method of the invention with respect to specific energy consumption by using the cavitation shredder 300 compared to conventional shredders known in the prior art in the case of five waste paper composites to be separated in different ways. Furthermore, Figure 7 shows the potential percentage savings, in particular of the dissolution time of fiber composites or fiber composite materials, which was also determined by measurements in the five test series. The test series were recorded at the test facility under identical test conditions at a water temperature of 8 °C and a consistency of 12.5%. These test parameters do not represent restrictions and also operational parameters for the functional installation 200, but only serve testing purposes for the series of tests in the test installation. It can be seen from Figure 7 that significant energy savings were obtained in all five series of tests with different paper composites used by using the method of the invention 100 using the cavitation shredder 300 compared to conventional methods and shredders. Energy savings here range from 37% for LWC paper to 65% for paper coated with PE on both sides. Advantageously, through lower energy consumption, costs can be reduced for operating the process and installation for separating fibers from fiber composites or fiber composite materials. Furthermore, the reduced dissolution time in a range of 43% to 71% compared to conventional methods is advantageous. This indirectly allows for an additional cost reduction, increasing productivity, since in the same process time, more fiber composites can be processed and separated for a shorter dissolution time than in conventional methods. Furthermore, advantageously reduced through the temporally reduced dissolution duration is also the treatment time for immersion and swelling of fiber composites or fiber composite materials, whereby the waste separated from the fibers is not unnecessarily crushed and does not need to be separated into subsequent high-cost steps, of the recycled fibers themselves. Furthermore, damage to the fibers due to internal friction is reduced due to the shorter treatment time, which allows for greater yield and quality of recyclable fibers. LIST OF NUMERICAL REFERENCES 100 Method 101 Process step filling the container 102 Process step gas-tight closing of the container 103 Process step mixing water and fiber composite 104 Process step generating kinetic energy 105 Process sub-step reducing pressure internal container 106 Process sub-step pressure equalization in the internal space of container 107 Cyclic sequence repetition of process step kinetic energy generation 200 Installation for fiber separation 210 main motor 211 pulley 212 pulley 213 belt 220 vacuum pump 221 vacuum tube 222 pressure transducer 240 seal water pump 241 seal water pipe 242 rotor slip ring seals 243 vacuum pump slip ring seal 250 feed water pipe 251 Inductive flow meter 252 feed water valve 300 cavitation defibrator 310 container 320 slide valve (emptying) 330 filling cap 331 closed position 332 open position 333 direction of movement 334 cover structure 340 ventilation pipe 341 ventilation pipe valve 342 ventilation pipe valve connection 343 connection of ventilation pipe valve 344A guide tube 344B guide tube 345 orifice 346 internal cylinder chamber 347 central switching shaft 348 piston 349 external pressure chamber 350 drive 360 protruding and surrounding rubber seal 370 straight guide 371 wheels 372 brush ruler

Claims (19)

1. METHOD (100) FOR SEPARATING FIBERS, using the following elements: i) a container (310) with a predefined reception volume; ii) a vacuum pump (220), which is connected by a vacuum tube (221) and a valve to the volume of the container; iii) a ventilation tube (340) with a predefined transverse opening and at least one valve (341), wherein the valve (341) is switched, in a time interval of 19 ms to 41 ms, from a closed state to a open state and, in a time interval of 20 ms to 45 ms, from the open state to the closed state; and the method is characterized by comprising the following steps: iv) filling the container (310) with a predefined amount of water and at least one fiber composite; v) ) close the container (310) gas-tight; vi) ) mix the water and the fiber composite by stirring; vii) after completion of steps i) to iii), generate kinetic energy in the fiber composite through the steps; viii) reduce the internal pressure of the container, in relation to a pressure outside the container, to a maximum of -950 hPa; and ix) equalize the pressure inside the container with the pressure outside the container to generate cavitation in the fiber composite; wherein the equalization step (vi) occurs within a time interval of 0.001 s and 1 s. 2. METHOD, according to claim 1, characterized in that the valve is connected by the vacuum tube (221) to a non-return valve. 3. METHOD, according to claim 1, characterized in that the valve (341) is switched in a time interval of 19 ms to 27 ms, from the closed state to the open state, and/or in a time interval of 20 ms to 39 ms, from the open state to the closed state. 4. METHOD, according to any one of claims 1 or 2, characterized in that step (vi) preferably occurs within a time interval of 0.001 s to 0.1 s. 5. METHOD, according to any one of claims 1 to 4, characterized in that the fiber composite is selected from a group of fiber systems that includes natural fibers, such as vegetable fibers and/or mineral fibers and/or chemical fibers, formed by natural polymers of plant or animal origin, natural polymers and/or synthetic polymers and films of natural polymers and/or synthetic polymers and/or metal and mixtures thereof. 6. METHOD, according to any one of claims 1 to 5, characterized in that, in addition to water and the fiber composite, at least one other additive is added, which is selected from a group comprising acids, alkaline solutions , dispersing agents, wetting agents and combinations thereof. 7. METHOD according to any one of claims 1 to 6, characterized in that the fiber composite has been crushed before introduction into the container and preferably the individual parts of the fiber composite have an edge surface of less than 10,000 mm2. 8. METHOD, according to claim 7, characterized in that the surface of the edges of the individual parts of the fiber composite increases in a manner essentially proportional to the receiving volume of the container (310). 9. METHOD, according to any one of claims 1 to 8, characterized in that, during step (iv), through the effect of mechanical energy, a differential pressure is maintained, at least, during a period of action of 2 minutes. 10. METHOD, according to any one of claims 1 to 9, characterized in that step (iv) is repeated in a predefined number of passes. 11. METHOD, according to any one of claims 9 or 10, characterized by the first passage of step (iv) taking place under differential pressure with the action period. 12. METHOD, according to any one of claims 10 or 11, characterized in that step (iv) is repeated by varying the period of action in at least four other passes. 13. METHOD, according to any one of claims 1 to 12, characterized in that step (v) is completed within a time interval of 60 s to 120 s. 14. METHOD, according to any one of claims 1 to 13, characterized by the negative pressure inside the container (310) after step (v) being a maximum of -700 hPa. 15. METHOD according to any one of claims 1 to 14, characterized by the material of a suspension of substances filled in the container (310), which consists of at least one liquid, comprising water or water and at least one other additive, and a composite of fibers as a proportion of solid matter, lies in a ratio of liquid to proportion of solid matter in a range between 2% and 35%. 16. METHOD, according to any one of claims 1 to 15, characterized by, after step (vi), accelerating the gas flowing in the container (310) after opening the valve (341) or valves (341) lies in a range between 2,000 m/s2 and 20,000 m/s2. 17. METHOD, according to any one of claims 1 to 16, characterized by, after step (vi), the flow velocity of the gas flowing in the container (310) after opening the valve (341) or valves ( 341) is located in a range between 43 m/s and 750 m/s. 18. METHOD, according to any one of claims 1 to 17, characterized by the ratio between the volume of the container and the effective cross-sectional surface of the ventilation tube (340) or the valve(s) (341) in the ventilation pipe (340), according to formula 1 below (Formula 1), is located in a range between 10,000 and 100,000 19. METHOD, according to claim 1, characterized by step v) further comprising decreasing the internal pressure of the container to between -700 and -950 hPa.