Polyurethane reaction in a tapering reactor

Abstract

The present invention relates to a continuous process for reacting a plastic material containing polyurethane, comprising the following steps, namely a reaction mixture comprising - a plastic material present as a solid and containing polyurethane, and further - an aqueous medium optionally containing reaction additives, providing a reaction mixture, in which the mass ratio of water of the aqueous medium to polyurethane in the reaction mixture is 0.6 to 1 or less; conveying the reaction mixture by means of a first screw conveyor arranged in a first line to a filling opening designed as a pressure lock of a reactor which tapers in the conveying direction at at least one end region; conveying the reaction mixture by means of a reactor screw conveyor arranged in the reaction vessel to the end region of the reactor at a temperature of 180 °C to 270 °C and a pressure of > 1 bar to 60 bar; transferring, in the end region of the reactor, the reaction mixture thus pressure- and heat-treated via a discharge opening designed as a pressure lock to a second line; conveying the pressure- and heat-treated reaction mixture by means of a second screw conveyor arranged in the second line; providing an evaporation zone in the second line at a temperature higher than the temperature in the reactor; removing gaseous components in the evaporation zone via at least one degassing point and obtaining, in the evaporation zone or downstream of the evaporation zone, a reaction mixture which has been pressure- and heat-treated and from which the gaseous components have been removed; a method comprising the above steps.

Description

Technical Field

[0001] The present invention relates to a method for reacting a plastic material containing polyurethane and a corresponding apparatus.

Background Art

[0002] Due to its many adjustable properties, polyurethane is widely used in industrial and household products. Examples of such products are foams, paints, adhesives, casting materials, hoses, seals, floor coverings, mattresses, automotive parts, parts of sports equipment, parts of shoes, and the like.

[0003] Therefore, when the corresponding products are damaged or reach their service life, a large amount of polyurethane waste is generated.

[0004] Therefore, attempts have been made in the past to recycle polyurethane. For example, European Patent No. 01976719 describes a method of hydrolyzing a polyurethane resin by contacting it with only water at a high temperature.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] The problem of the present invention is to provide an improved method.

Means for Solving the Problems

[0007] The present invention becomes apparent from the features of the independent claims. Advantageous developments and embodiments are the subject matter of the dependent claims.

[0008] Within the scope of this invention, plastic materials are understood to be materials containing plastics, ranging from pure plastics to mixtures containing plastics. The term "plastic" is used in a general sense and refers to substances produced by synthesis, for example, substances produced within the scope of organic synthesis, such as polymers produced by polymerization, polyaddition and / or polycondensation from one or more different monomers. Plastics are generally classified into thermosetting resins, thermoplastic resins, elastomers and thermoplastic elastomers. Well-known examples of plastics are polyethylene, polycarbonate, polyacrylic, polymethacrylic, polyacrylamide, polystyrene, acrylonitrile-butadiene rubber, styrene-butadiene rubber, chloroprene rubber, butadiene rubber, ethylene-propylene-diene rubber, and polyurethane. In special embodiments, plastic materials are intended to include only hydrolyzable plastics, such as polyester, polyamide, and / or polycarbonate, in addition to polyurethane, for example. Plastics are also considered plastics within the scope of this invention if they are vulcanized natural rubber, for example, vulcanized natural rubber, which has been previously used in technical tasks, for example, generated within the scope of mattress manufacturing, or chemically treated. However, lignin, i.e., wood, is not included. Plastics may, depending on their intended use, include other substances such as plasticizers, antibacterial agents, antioxidants, stabilizers against ultraviolet light, flame retardants, dyes, or residues of polymerization initiators. In addition to petroleum-based starting products, plastics are also produced within the scope of chemical synthesis from next-generation raw materials, or within the scope of microbiological processes using appropriately made enzymes or producing organisms, within the scope of the concepts of sustainability and renewables. The plastic-containing mixtures mentioned at the beginning are either mixtures of pure plastics or mixtures that also include one or more non-plastics, such as metals, ceramics, or glass.Preferably, one or more plastics in such a mixture, including non-plastics, constitute a relatively large proportion in terms of mass or volume, for example, at least 67%, at least 75%, at least 80%, at least 90%, at least 95%, at least 98%, or at least 99%. It is preferable that non-plastics are not present in the plastic material, and methods for reducing non-plastics are known to those skilled in the art, including, for example, manual removal of non-plastics, magnetic removal of magnetic metals or metal alloys, or separation of plastics from other materials of similar density, possibly by air sieves or oscillating or vibrating devices, due to density differences of materials of different densities. Within the plastic material, polyurethane constitutes the largest mass proportion, preferably more than 60%, for example, at least 65%, at least 70%, at least 75%, at least 80%, at least 85%, at least 90%, or at least 95%, and is therefore the overwhelming main component. For example, discarded polyurethane mattresses often contain a relatively small proportion of polyethylene or polypropylene derived from the surface material.

[0009] The plastic materials used in this method include one or more hydrolyzable plastics consisting of polyurethane and, optionally, further selected from polyester, polyamide, or polycarbonate, or polyurethane and, optionally, further selected from polyester, polyamide, or polycarbonate and / or mixtures thereof. According to a special embodiment, the plastic material consists of polyurethane or a polyurethane mixture, or consists of polyurethane and polyester or a polyester mixture, such as polyethylene terephthalate or a polyethylene terephthalate mixture, or consists of a polyurethane / polyolefin composite material, wherein the proportion of polyurethane in the composite material is preferably at least 50 percent by mass. Within the hydrolyzable plastic, polyurethane accounts for the largest mass proportion, preferably more than 60%, for example, at least 65%, at least 70%, at least 75%, at least 80%, at least 85%, at least 90%, or at least 95%, and is therefore the overwhelming major component. For example, the plastic material is a mattress or waste from mattress manufacturing, and the raw material contains polyurethane as a hydrolyzable component. In this case, polyurethane can exist particularly as a foam, and within the scope of the present invention, a special advantage arises in that a high-volume starting material (i.e., a foam that can be compressed to some extent but always tends to occupy a large volume, and therefore requires a appropriately sized first line and reaction vessel) is reacted in the presence of a relatively small volume of reaction medium, and the volume obtained after appropriate pressure and heat treatment is significantly smaller. In other words, a substantially bulky solid, i.e., a foam, is transformed into a more easily handled form with a significantly larger liquid proportion and smaller volume, thereby solving a major problem in the polyurethane waste and recycling industry.

[0010] One aspect of the present invention relates to a continuous method for reacting plastic materials comprising at least one hydrolyzable plastic, the method comprising the steps of: providing a reaction mixture comprising a plastic material that exists as a solid and includes polyurethane, and further comprising an aqueous medium, wherein the mass ratio of water to polyurethane in the aqueous medium in the reaction mixture is 0.6 to 1 or less; further conveying the reaction mixture by a first screw conveyor located in a first line to a filling opening designed as a pressure lock of a reactor that tapers in the conveying direction in at least one end region; and further heating at a temperature of 180°C to 270°C > 1b by a reactor screw conveyor located inside the reactor. The process includes the steps of: transporting the reaction mixture to the end region of the reactor at a pressure of ar ~ 60 bar; further, transferring the thus pressure- and heat-treated reaction mixture to a second line through an outlet opening designed as a pressure lock at the end region of the reactor; further, transporting the pressure- and heat-treated reaction mixture by a second screw conveyor located in the second line; further, providing an evaporation zone in the second line at a temperature higher than the temperature inside the reactor; and further, removing gaseous components in the evaporation zone through at least one degassing point; and obtaining a pressure- and heat-treated reaction mixture, from which gaseous components have been removed, in or downstream of the evaporation zone. In this case, the reaction mixture may be in a state from which gaseous components have been partially or completely removed.

[0011] The aqueous medium contains or consists of water and may optionally contain reaction additives.

[0012] From the obtained pressure and heat-treated reaction mixture, the liquid phase and the contained solids can optionally be separated, for example, by centrifugation or filtration, and the resulting solids can optionally be dried.

[0013] The mass ratio of water in the aqueous medium to polyurethane in the plastic material is 0.6:1 or less, particularly 0.5:1 or less, for example, 0.45:1, resulting in a large excess of polyurethane in terms of mass ratio. While larger amounts of aqueous medium are possible, it was surprisingly confirmed that a good reaction rate can be achieved with the aforementioned mass ratio. Therefore, it is not necessary to suspend the plastic material in the relevant aqueous medium; it only needs to be moistened with it. Reducing water consumption is an important advantage in aiming for a circular economy that conserves resources.

[0014] At the start of the method, the reaction mixture is transported by a first screw conveyor to the filling opening of a reactor designed as a pressure lock. An example of a suitable pressure lock is the double lock known in the art. Further examples include a screw conveyor that transports the material while compressing it, or a screw conveyor that even has a return conveyor element that causes local compression of the material being transported, which in itself forms a pressure barrier and thus functions as a pressure lock. The volume of the reactor can range, for example, from the liter range to the cubic meter range, and even to the volumes of large-scale technologies of tens of cubic meters or more.

[0015] After passing through the pressure lock, the polyurethane in the plastic material, which initially exists as a solid, and possibly other hydrolyzable plastics contained within it, transition to the liquid phase as the reaction of the hydrolyzable plastics progresses, under the temperature and pressure conditions in the reactor and optionally in the presence of an aqueous medium containing reaction additives. Since the volume of the reaction mixture mainly comes from the plastic material due to its low water content, the volume of the plastic material gradually decreases as it is transported toward the outlet opening. Therefore, a reactor that tapers at least one end region can be used, which is advantageous because the required heating power decreases and the required space decreases as the taper progresses and the volume of the reaction mixture decreases accordingly.

[0016] This method is performed at pressures in the range of >1 bar to 60 bar, i.e., pressures higher than 1 bar of atmospheric pressure, e.g., 5 to 50 bar, 10 to 40 bar, or 20 to 30 bar, e.g., approximately 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, or 60 bar. During the execution of the method, the temperature is in the range of 180°C to 270°C, e.g., 180°C to 250°C, e.g., 190°C to 245°C, e.g., 200°C to 245°C, 200°C to 240°C, 210°C to 235°C, or 215°C to 230°C, e.g., 185, 190, 200, 210, 215, 220, 225, 230, 235, 240, or 250°C. Preferably, target temperature and target pressure are set, but it will be understood by those skilled in the art that during the execution of the method, actual values ​​may deviate from or fluctuate around the target values, and may be appropriately controlled or readjusted as needed. Temperature and pressure can be actively controlled. According to a special development, only the temperature is actively controlled, and the pressure is passively generated as an equilibrium pressure based on the then temperature of the aqueous reaction mixture in a given reaction volume. The rate of transport from the filling opening to the removal opening can be adjusted according to the reduction in solid content achieved, and can be reduced, for example, if optional sampling indicates that there is too much solid content in the pressure- and heat-treated reaction mixture. Non-limiting examples of the duration of pressure and heat treatment are, for example, 1 to 8 hours, for example 1.5 to 6 hours, for example 2 to 4 hours, for example 1, 2, 3, 4, 5, 6, 7 or 8 hours, ±0 to 59 minutes. In that case, for example, the duration of pressure and heat treatment is 45 to 250 minutes, particularly 45 to 240 minutes. However, it will be apparent to those skilled in the art that the duration can be adjusted accordingly to suit the specific course of the reaction; for example, it can be less than one hour if the reaction is very fast, and longer than eight hours if the reaction is very slow. This method is carried out continuously, and in some cases, a sample is taken from the reactor to determine the degree of reaction, and the duration is adjusted accordingly. The reaction is carried out in isolation from air. The reaction can be carried out under anaerobic conditions in particular.For example, appropriate measures for creating anaerobic conditions are known to those skilled in the art, such as by heating to expel oxygen from the aqueous reaction mixture, generating vapor, and / or by flashing with an inert gas such as nitrogen.

[0017] The tapering in the conveying direction of the reactor can be continuous, thereby causing the cross-section between the filling opening and the removal opening to continuously decrease, for example, linearly. As an alternative, the cross-section of the reactor can be intended to be initially constant downstream of the filling opening. Thus, it is taken into consideration that after the introduction of the reaction mixture into the reactor, the reaction must first begin to proceed, and therefore less volume reduction of solids is expected at the filling opening. In this case, the cross-section of the reactor can be reduced at a certain distance from the filling opening. In fact, surprisingly, it has been found that even with a small proportion of aqueous medium, the conversion from solid to liquid begins after a short period of conveying within the reactor, accompanied by a decrease in solid volume. Therefore, for example, the first 5-20% of the reactor length, for example 10-15% of the length, can have a constant cross-section, and the remaining portion can be intended to taper, for example, linearly. According to one embodiment, the conveying direction within the reactor follows gravity.

[0018] After passing through the reactor, the pressurized and heat-treated reaction mixture is transferred to a second line through an outlet opening designed as a pressure lock. At this point, the reaction mixture has a significantly reduced volume of solids compared to the initially used reaction mixture, and in some cases, no solids are present. Instead, the pressurized and heat-treated reaction mixture is a liquid, or a liquid containing solids. Advantageously, this achieves the goal of the method: a reduction in the volume of solids used, consisting of plastic materials present as solids and possibly other solids. For example, a reduction of up to 95%, up to 90%, or 4-50%, e.g., 5-30%, e.g., 7-25%, or 10-15% of the volume of solids used is possible. Significant reductions are possible, especially with foams.

[0019] Another optional objective of the method is to further utilize the products obtained within the range of the reaction. Therefore, to provide a more uniformly pressure- and heat-treated reaction mixture, an evaporation zone at a temperature higher than the reactor temperature is provided in a second line. Thus, the evaporation zone is suitable for removing components whose boiling point is higher than the reactor temperature but lower than the evaporation zone temperature. This is done via one or more degassing points, where gaseous components with corresponding boiling points are removed. At the degassing points, cold traps, vacuum traps, and / or valves or regulators for maintaining a pressure gradient, as known in the art, may be used as needed. The removed gaseous components can be used for further purposes. In or downstream of the evaporation zone, a pressure- and heat-treated reaction mixture is obtained, from which gaseous components with boiling points higher than the reactor temperature have been removed.

[0020] For improved reaction, plastic materials are preferably used in a pulverized state, especially if they include plastics that do not swell in water. In this case, pulverization methods common in the art can be used, for example, the plastic material may be cut, torn, flaked, shredded, granulated, pulverized, or powdered after potentially lowering the temperature beforehand to increase brittleness. Non-limiting examples of the size of plastic particles used include about 0.5 cm², especially for porous or large surface area plastic materials. 3 ~10cm 3 (0.5ml to 10ml), for example, about 1cm 3 ~5cm 3 The plastic particles, or the diameter measured at their widest point, are approximately 10, 5, 2, 1, 0.5, 0.1, 0.05, or 0.01 millimeters.

[0021] According to one embodiment, the temperature of the evaporation zone is intended to be above the boiling point of the nitrogen-containing components and below the boiling point of the high-boiling-point components. The corresponding nitrogen-containing components are generated when nitrogen-containing plastics are included in the plastic material, particularly in the case of polyurethane. The nitrogen-containing components are usually diamines or their decomposition or reaction products. By removing these nitrogen-containing components, on the one hand they can be used separately for further use, and on the other hand a more uniform pressure and heat-treated reaction mixture can be provided. In particular, reaction mixtures from which nitrogen-containing components have been depleted or removed are better suited for subsequent processing steps, such as thermal decomposition.

[0022] In one embodiment, the evaporation zone temperature is intended to be 265°C to 300°C, particularly 265°C to 280°C, for example, 270°C to 280°C. Within these temperature ranges, it has been advantageously confirmed that a significant proportion of nitrogen-containing components can be partially or completely removed from the pressure- and heat-treated reaction mixture via at least one degassing site. In particular, at evaporation zone temperatures from 265°C to 280°C, it has been confirmed that diaminotoluene can be removed from the reaction mixture in gaseous form via the degassing site. Similarly advantageously, the remaining pressure- and heat-treated reaction mixture, from which the nitrogen-containing components have been thus partially or completely removed, contains components that boil at higher temperatures. While not intending to be bound by theory, considering the polyurethane present in the reaction mixture initially used, these are likely polyols and their decomposition and / or conversion products.

[0023] In one embodiment, in the second line, it is contemplated that a dehydration zone is arranged upstream of the evaporation zone, the temperature of which is higher than the boiling temperature of water and lower than the boiling temperature of the nitrogen-containing components. Thus, gaseous water vapor can be withdrawn through one or more water vapor withdrawal points within the dehydration zone, thereby reducing the water content of the pressure- and heat-treated reaction mixture. This enables the provision of a pressure- and heat-treated reaction mixture, which is additionally partially or completely dehydrated and, thus, advantageously, exists in a more easily handleable solid form. If necessary, at the water vapor withdrawal points, cold traps, vacuum traps, as well as / or valves or regulating devices for maintaining a pressure gradient, known in the art, can be used.

[0024] The pressure within the second line can correspond to the pressure within the reactor or atmospheric pressure. In the first case described, an additional pressure lock can be provided at the end of the second line to transition to atmospheric pressure. In the last case described, the pressure is reduced to atmospheric pressure through the extraction opening of the reactor designed as a pressure lock. As another option, it is possible to use one or more additional pressure locks between the extraction opening, which is itself designed as a pressure lock, and the end of the second line to reduce the pressure stepwise.

[0025] According to one embodiment, in the second line where atmospheric pressure prevails, the temperature within the second line corresponds to at least the boiling point of water at the corresponding atmospheric pressure. This advantageously enables the reduction of the water content by providing a dehydration zone having at least one degassing point. In one development, it is contemplated that the temperature of the dehydration zone is lower than the boiling temperature of the nitrogen-containing components, in which case the dehydration zone is followed by an evaporation zone at a temperature higher than the boiling temperature of the nitrogen-containing components, and the nitrogen-containing components can be withdrawn from the pressure- and heat-treated reaction mixture from which water has been partially or completely removed through one or more corresponding degassing points in the evaporation zone.

[0026] According to one embodiment, the volume ratio of solid medium to aqueous medium in the reaction mixture supplied to the first line is 100:1 to 5:1, for example 75:1 to 10:1, or 30:1 to 20:1, for example 25:1. In this respect, it can be seen that the aqueous medium does not mainly contain the plastic material suspended as a solid (and possibly another solid), but rather consists of plastic material that is merely moistened with a significantly smaller amount of aqueous medium for the majority of its volume. For example, it can be intended that 0.05 to 0.2 parts by volume of aqueous medium per volume of polyurethane foam or per volume of solid is provided. Therefore, at the start of the reaction, the reaction mixture contains only plastic material moistened with aqueous medium, i.e., a solid substantially moistened with the reaction medium, and as conveying in the conveying direction progresses, the solid, which requires a larger volume, is transferred by the reaction to the liquid phase, which requires a smaller volume.

[0027] According to a particular embodiment, the ratio of the cross-sectional area of ​​the reactor before tapering to the cross-sectional area at the maximum tapering can be 10:1, especially 5:1, and especially 2:1. Advantageously, this takes into account the expected decrease in the volume of the solid.

[0028] According to one embodiment, the obtained pressure- and heat-treated reaction mixture is intended to be introduced directly or indirectly into a pyrolysis apparatus to carry out pyrolysis. The principle of pyrolysis itself is known and is based on the thermochemical conversion of a substance under the exclusion of external oxygen, usually in the temperature range of 150°C to 800°C. Within the scope of the methods described herein, the highest temperature in the reactor or in a second line downstream is preferably the lower limit of the temperature range, for example, the temperature range of 265°C to 800°C. This is, for example, the temperature range of 265°C to 500°C or 300°C to 500°C. Another example of a temperature range is 700°C to 800°C, particularly 750°C to 800°C, which is suitable for decomposing calcium carbonate present in plastic materials into calcium oxide and carbon dioxide, and thus for providing pyrolysis coke with little or no calcium carbonate as the pyrolysis product. The pyrolysis treatment is preferable to using the obtained pressure- and heat-treated reaction medium. If we consider that the mixture contains essentially polyols and, in some cases, conversion products, then additional washing or separation steps are necessary to ensure sufficient quality for further use. In contrast, thermal decomposition can advantageously yield polyol monomers that are considered to have a higher qualitative purity compared to polyols.

[0029] In preferred embodiments, the pressurized and heat-treated reaction mixture introduced directly or indirectly into the pyrolysis plant is a reaction mixture from which gaseous components having a boiling point lower than the evaporation zone temperature have been partially or completely removed beforehand. In particular, according to embodiments described herein, it is possible to supply reaction mixtures to pyrolysis that have a low proportion of nitrogen-containing components or do not contain such components. This makes it possible to provide pyrolysis products that can themselves be advantageously further used. In particular, liquid, gaseous, and solid pyrolysis products can be obtained during pyrolysis. With respect to liquid products, this is pyrolysis oil, which can itself undergo cracking, in which case a high proportion of nitrogen-containing components is an obstacle. The resulting pyrolysis gas can be used for power generation, and the problem of nitrogen oxide generation is mitigated due to the low proportion of nitrogen-containing components. Solid pyrolysis products, which are a type of pyrolysis coke, can be used for a variety of purposes, for example, as a substitute for carbon black or as petroleum coke that can similarly be used for power generation, so in this case as well, it is advantageous if the nitrogen-containing components are low or absent.

[0030] In a particularly preferred embodiment, the pressure- and heat-treated reaction mixture, which is directly or indirectly introduced into the pyrolysis equipment, passes through a dehydration zone before passing through an evaporation zone, where its water content is reduced, resulting in a mixture with low water content or no water at all.

[0031] According to one embodiment, the reaction additive optionally included in the aqueous medium is selected from nitric acid, carboxylic acid, urea, and / or biomaterials. A good reaction can be achieved using nitric acid. However, if a pressure- and heat-treated reaction mixture with a low proportion of nitrogen-containing components is desired, other reaction additives are preferred because nitric acid introduces additional nitrogen. In general, mineral acids such as hydrochloric acid or phosphoric acid, or mineral bases such as sodium hydroxide, are not very preferred because chlorine, phosphorus, and sodium components are present in the pressure- and heat-treated reaction medium, which may have unfavorable effects in the case of downstream thermal decomposition or when the resulting thermal decomposition products are used later. In contrast, alternative reaction additives that can achieve a good reaction include carboxylic acids, particularly linear saturated monocarboxylic acids such as formic acid, acetic acid, propionic acid, butyric acid, or pentanoic acid, hexanoic acid, and heptanoic acid; dicarboxylic acids such as oxalic acid (ethanedioic acid), malonic acid (propandioic acid), succinic acid (butanedioic acid), glutaric acid (pentanedioic acid), adipic acid (hexanedioic acid), malic acid (2-hydroxybutanedioic acid), and tartaric acid (2,3-dihydroxybutanedioic acid); and tricarboxylic acids such as 3-carboxy-2-oxopentanedicarboxylic acid (oxasuccinic acid), propane-1,2,3-tricarboxylic acid, citric acid (2-hydroxypropane-1,2,3-tricarboxylic acid), and isocitric acid (1-hydroxypropane-1,2,3-tricarboxylic acid). Yet another reaction additive is urea. The proportion of urea in the aqueous medium relative to the total mass of the aqueous medium is, for example, 1 to 45 mass percent, particularly 1 to 20 mass percent, for example 1 to 10 mass percent, for example 1 to 7 mass percent, for example 1.5 to 5 mass percent, 1.5 to 4 mass percent, 2 to 4 mass percent, 2.5 to 3.5 mass percent, or 3 mass percent. Further ranges or further concentration examples include 5 to 10 mass percent, 1 mass percent, 5 mass percent, 7.5 mass percent, and 10 mass percent. In terms of the ratio of the amount of urea used to the degree of degradation of polyurethane achieved, a range of 1 mass percent to 10 mass percent, for example 2.5 mass percent to 10 mass percent, for example 2 mass percent to 7.5 mass percent, for example 3 mass percent to 5 mass percent is preferred.

[0032] According to a special embodiment, the aqueous medium contains 2.5 to 10 mass percent urea, in which case the duration of pressure and heat treatment is preferably 45 to 250 minutes, particularly 45 to 240 minutes. The ratio of the aqueous medium containing urea to the plastic material containing polyurethane can be, for example, 0.2 ml / g to 5 ml / g, particularly 0.4 ml / g to 5 ml / g.

[0033] Furthermore, the reaction additive can be a biomaterial. Within the scope of the present invention, a biomaterial is understood to be a plant material, an animal material, or a microbiome, such as a whole plant, or a part of a plant such as wood, leaves, stems, roots, or seeds, such as horticultural waste or grass clippings. Preferably, the biomaterial is a plant material. According to a special embodiment, the biomaterial is wood, in particular, wood in the form of crushed wood such as sawdust, wood chips, or shredded wood. Using a plant material, such as wood, after adequate dewatering in a dewatering zone, a well-flowable solid is obtained that is well suitable for conveying, for example, by a screw conveyor. This makes subsequent use, such as conveying and introducing into a pyrolysis facility, much easier. Thus, the presence of a plant material in the reaction mixture brings about considerable improvement. The mass ratio of the plastic material to the biomaterial, especially the plant material, can be, for example, 3:1 to 1.5:1, or for example, 2:1. In particular, when the mass ratio of the plastic material and biomaterial was one-third or more of the total mass, for example 33-50 mass percent, especially 33-45 mass percent, for example 34-40 mass percent, a solid that could flow very well after passing through the dehydration zone in a pressure- and heat-treated reaction medium was obtained.

[0034] The aforementioned reaction additives can be used individually or as any mixture of two or more of those described above.

[0035] An example of a mixing ratio of plastic material to an aqueous medium containing reaction additives is 2 to 25 liters of plastic material moistened with at least 0.08 to 1 liter of aqueous medium. The aqueous medium may contain 3 to 50 mass percent, particularly 4 to 40 mass percent, for example, 4 to 20 mass percent of nitric acid, carboxylic acid, dicarboxylic acid, tricarboxylic acid, and / or urea. When mixing with biomaterials, it is possible to intend for the plastic material to account for 55 to 95 volume percent, particularly 67 to 95 volume percent, and the biomaterial to account for a corresponding 5 to 45 volume percent, particularly 5 to 33 volume percent. The biomaterial can be mixed with the plastic material and then the aqueous medium can be added, or it can be mixed with the aqueous medium first and then with the plastic material, or all three components can be mixed simultaneously.

[0036] Insofar as the plastic material and / or hydrolyzable plastic contained herein is a compressible plastic, particularly a foam, the volume stated refers to the uncompressed plastic.

[0037] According to one embodiment, one or more pressure barriers are intended to be placed in the first line and / or the second line. When a pressure gradient is formed, this is advantageously used to prevent the reaction mixture from being transported in the opposite direction to the desired transport direction.

[0038] According to one embodiment, the reactor screw conveyor inside the reactor can extend only to a portion of the reactor, for example, to the portion of the reaction vessel where a high proportion of solids still exist, with respect to the conveying direction.

[0039] According to another embodiment, the reactor screw conveyor extends with a corresponding taper within the tapering end region of the reactor, thereby advantageously ensuring the transport of the reaction medium toward the outlet opening along the entire transport path.

[0040] The conveying speed of the reactor screw conveyor can be controlled. This opens up the possibility of influencing the residence time of the reaction mixture in the reactor, which is advantageous. If the reaction is slower than initially expected, the conveying speed can be reduced, for example, to increase the residence time and enhance the reaction. If the reaction is faster than initially expected, the conveying speed can be increased to increase the reactor throughput.

[0041] According to one embodiment, water obtained after removing solids from the acquired pressure and heat-treated reaction mixture and from which gaseous components have been removed, and / or water obtained from gaseous water extracted via a steam extraction point, is intended to be added to the provided reaction mixture after optionally adding reaction additives. Thus, advantageously, a recycling process is performed in which water from the already used aqueous medium is returned in a continuous manner, at least partially, thereby reducing resource consumption.

[0042] Another aspect of the present invention relates to an apparatus for carrying out the method described herein. The apparatus comprises a first line in which a first screw conveyor is located inside, the first line leading to a reactor through a filling opening designed as a pressure lock, and a reactor screw conveyor located inside the reactor, the reactor tapering at least one end region, As a pressure lockThrough a designed outlet opening, a second screw conveyor is located in a second line, which includes an evaporation zone that can be set to a higher temperature than that inside the reactor. The second line has a degassing point in the evaporation zone from which gaseous components can be removed from the second line. Thus, such an apparatus is suitable for conveying the reaction mixture described herein, namely a reaction mixture comprising a plastic material containing polyurethane and existing as a solid, and an aqueous medium further containing a reaction additive for wetting the plastic material, via the first screw conveyor of the first line to a filling opening designed as a pressure lock of the reactor, with at least one end region tapering. After entering the reactor for the reaction mixture through the filling opening, the reaction mixture is exposed to the prevailing pressure and temperature conditions therein to react and can be transferred to the second line via an outlet opening designed as a pressure lock in the end region of the reactor. The second screw conveyor located in the second line can convey the pressurized and heat-treated reaction mixture to an evaporation zone, where gaseous components can be removed via at least one degassing point. The pressure- and heat-treated reaction mixture, from which the gaseous components have been depleted, can be removed after being further transported in a second line for, for example, a pyrolysis treatment, or it can be supplied directly to a pyrolysis facility, optionally demonstrating an extension of the apparatus described herein.

[0043] In another embodiment of the apparatus, a dehydration zone is located upstream of the evaporation zone in the second line, the temperature of the dehydration zone is higher than the boiling point of water and lower than the boiling point of the nitrogen-containing components, and gaseous water can be removed in the dehydration zone through a steam extraction point. From the pressurized and heat-treated, water-depleted or water-removed reaction mixture remaining in the second line after the steam has been removed, the remaining gaseous components, particularly the gaseous nitrogen-containing components, are then partially or completely removed in the evaporation zone. The remaining pressurized and heat-treated, water-depleted or water-removed reaction mixture, and the other gaseous components depleted or removed, can also be extracted and supplied, for example, directly or indirectly to pyrolysis.

[0044] See also the implicit disclosure of apparatus used in relation to the method, and vice versa.

[0045] Further advantages, features, and details will become apparent from the following description, in which at least one exemplary embodiment is described in detail with reference to the drawings as appropriate. Identical, similar, and / or functionally identical parts are given the same reference numeral. [Brief explanation of the drawing]

[0046] [Figure 1] This is a schematic cross-sectional view of a reactor with an evaporation zone. [Figure 2] This is a schematic diagram of a reactor having an evaporation zone and a dehydration zone. [Modes for carrying out the invention]

[0047] The drawings are schematic and not necessarily to scale, showing only the essential components. [Examples]

[0048] Example 1: Preparation of reaction mixture In the pilot test, a polyurethane foam mixture obtained from mattresses at the end of their lifecycle was used as the plastic material. Mattresses with a unit volume weight of approximately 40 kg per cubic meter were shredded, and the resulting material was a mixture of standard ether foam, HR foam, and viscoelastic foam. 400 g of this material was placed in a 10-liter bucket and filled to approximately 85%.

[0049] To the shredded material, 100g of sawdust and 100g of shredded wood waste were added as biomaterials, resulting in a starting density of approximately 700kg per cubic meter. Plastic material was then mixed with the biomaterials, but the bucket was still filled to about 85%.

[0050] As an aqueous medium, plant material was added as a reaction additive, and 150 ml of the reaction medium, which had been pressure- and heat-treated based on preliminary experiments assuming a pH of 4 during the conversion process, was used. This aqueous medium was mixed with a mixture of plastic material and biomaterial and moistened with it. The resulting reaction mixture, i.e., a mixture of shredded mattress material and biomaterial moistened with the reaction medium, was approximately 8.6 liters.

[0051] Example 2: Supply to the reactor A Buchi reactor pressure vessel, designed with a capacity of 10 liters and a maximum pressure of 60 bar, was used as the reactor. The prepared reaction mixture was placed in a stainless steel inner bucket (inliner), which was also placed inside the Buchi reactor pressure vessel. Subsequently, the Buchi reactor pressure vessel was compacted and sealed with a lid.

[0052] Example 3: Reaction Implementation The objective of this experiment was to confirm the decrease in the solid content due to the reaction. The reactor was first heated to a jacket temperature of 260°C, which was reached in approximately 6-10 minutes. It was then maintained at 260°C for 1 hour, followed by 240°C for 2 hours, during which time the reactor reached equilibrium pressure. Subsequently, the pressure vessel was actively and rapidly cooled to ambient temperature.

[0053] Example 4: Determination of residual solid content After the reaction was complete, the liquid phase of the pressurized and heat-treated reaction medium was added dropwise to determine the volume of the residual solid. No original components were recognizable in the residual solid; rather, it was a brownish-black mass, and its volume was determined to be 1.2 liters. Thus, the volume of the solid was reduced to approximately 14% of the starting volume by the transformation.

[0054] Other experiments using urea solution as a reaction additive have confirmed partial or complete liquefaction. Therefore, a reduction of 90–95% ± 5% in solid volume is realistically achievable.

[0055] Example 5: In another experiment, 500 g of shredded mattress material was placed in a Buchi reactor pressure vessel with 150 ml of water containing 40 g of citric acid and 50 g of 96 percent acetic acid. The mattress material used consisted substantially of polyurethane foam with polyethylene and polypropylene content.

[0056] The reaction mixture was heated to 260°C under equilibrium pressure for 60 minutes, and then maintained at 250°C for 120 minutes.

[0057] After the reaction mixture, which had been subjected to pressure and heat treatment in this manner, was cooled, the solid particles made of polyethylene / polypropylene, due to their low density, floated in the liquid phase and could be easily separated mechanically.

[0058] After the separation of the liquid phase of the pressure- and heat-treated reaction mixture, a dark-colored material remained. When this material was dried, it resulted in a volume reduction of approximately 95% compared to the volume of the plastic material initially used.

[0059] Explanation of the diagram Figure 1 shows a schematic diagram of reactor 16. A reaction mixture, which exists as a solid and comprises a plastic material containing at least one type of polyurethane, and optionally an aqueous medium containing reaction additives, is filled into a first line 10 via a filling funnel (not shown in detail). In line 10, the reaction mixture is transported by a first screw conveyor 12 to a filling opening 14 of reactor 16, which is designed as a pressure lock, and introduced into reactor 16 through the filling opening. The pressure inside reactor 16 is >1 bar to 60 bar at a temperature of 180°C to 270°C. A reactor screw conveyor 18, located inside reactor 16, transports the reaction mixture toward the end region of reactor 16. The reaction occurring inside reactor 16, between polyurethane and, optionally, other hydrolyzable plastics contained in the plastic material, reduces the volume proportion of solids in the reaction mixture, allowing reactor 16 to taper toward the end region. The reaction mixture is introduced into a second line 22 through an outlet opening 20 of reactor 16, which is designed as a pressure lock, and conveyed by a second screw conveyor 24 located within it. Within the second line 22 is an evaporation zone 26, whose temperature is higher than that of reactor 16. At this temperature, the gaseous components can be removed from the second line 22 through a degassing point 28, and as a result, the pressure and heat-treated reaction mixture, with the gaseous components considerably depleted, can be conveyed downstream of the outlet opening in the second line 22 and acquired. Details of the first screw conveyor 12, the second screw conveyor 24, or reactor screw conveyor 18, or the motors, etc., for driving heating devices to heat reactor 16 or evaporation zone 26 are not shown.

[0060] Figure 2 shows another schematic diagram of reactor 16 corresponding to reactor 16 shown in Figure 1, but additionally, a dehydration zone 30 in a second line 22. The dehydration zone 30 is located before the evaporation zone 26 in the direction of transport of the conveyed reaction mixture. The dehydration zone 30 is designed to be at a temperature higher than the temperature inside reactor 16 but lower than the temperature inside the subsequent evaporation zone 26. The temperature inside the dehydration zone 30 is selected so that water evaporates under appropriate pressure and temperature conditions.

[0061] The embodiments and / or individual elements thereof referred to herein can be freely combined with one another. Although the present invention has been illustrated and described in detail by preferred embodiments, the present invention is not limited by the disclosed examples, and those skilled in the art can derive other modifications without departing from the scope of protection of the present invention. Thus, it is clear that there are numerous possible modifications. It is also clear that the exemplary embodiments are merely examples and should not be construed as limiting the scope of protection, applicability, or configuration of the present invention in any way. Rather, the foregoing description and the illustrations are intended to enable those skilled in the art to concretely implement the exemplary embodiments, thereby enabling them to make various changes, for example, with respect to the function or arrangement of the individual elements referred to in the exemplary embodiments, with an understanding of the spirit of the disclosed invention, without departing from the scope of protection defined by the claims and their legal equivalents, such as the full description in the specification. [Explanation of Symbols]

[0062] 10 First line 12. First screw conveyor 14 Filling opening 16 Reactors 18. Reactor screw conveyor 20 Removal opening 22 Second line 24. Second screw conveyor 26 Evaporation Zone 28 Degassing points 30 Dehydration Zone 32 Steam extraction points

Claims

1. A continuous method for reacting plastic materials including polyurethane, comprising the following steps: A reaction mixture, - A plastic material that exists as a solid and contains polyurethane, and further - A step of providing a reaction mixture comprising an aqueous medium, wherein the mass ratio of water to polyurethane in the aqueous medium is 0.6 to 1 or less. A step of transporting the reaction mixture to a filling opening designed as a pressure lock of a reactor that tapers in the transport direction at at least one end region, using a first screw conveyor positioned on a first line, A process of transporting the reaction mixture to the end region of the reactor at a temperature of 180°C to 270°C and a pressure of >1 bar to 60 bar using a reactor screw conveyor placed inside the reactor, In the end region of the reactor, the reaction mixture, which has been pressurized and heat-treated in this manner, is transferred to a second line through an outlet opening designed as a pressure lock. A step of transporting the pressure and heat-treated reaction mixture by a second screw conveyor located in the second line, The process involves providing an evaporation zone within the second line at a temperature higher than the temperature inside the reactor, A step of removing gaseous components in the evaporation zone through at least one degassing point, and obtaining the pressure- and heat-treated reaction mixture from which gaseous components have been removed in the evaporation zone or downstream of the evaporation zone, A method of including.

2. The method according to claim 1, characterized in that the temperature of the evaporation zone is above the boiling point of the nitrogen-containing component and below the boiling point of the high-boiling point component.

3. The method according to claim 1, characterized in that the temperature of the evaporation zone is 265°C to 300°C.

4. The method according to claim 1, characterized in that, in the second line, a dehydration zone is located upstream of the evaporation zone, the temperature of the dehydration zone is higher than the boiling point of water and lower than the boiling point of nitrogen-containing components, and gaseous water can be extracted in the dehydration zone through a water vapor extraction point.

5. The method according to claim 1, characterized in that the atmospheric pressure is dominant within the second line and the temperature is at least equivalent to the boiling point of water at atmospheric pressure.

6. The method according to claim 1, characterized in that the volume ratio of the solid to the aqueous medium is 100:1 to 5:

1.

7. The method according to claim 1, characterized in that the ratio of the cross-sectional area of ​​the reaction vessel before tapering to the cross-sectional area at the maximum tapering is 10:

1.

8. The method according to any one of claims 1 to 6, characterized in that the ratio of the cross-sectional area of ​​the reaction vessel before tapering to the cross-sectional area at the maximum tapering is 5:

1.

9. The method according to any one of claims 1 to 6, characterized in that the ratio of the cross-sectional area of ​​the reaction vessel before tapering to the cross-sectional area at the maximum tapering is 2:

1.

10. The method according to claim 1, characterized in that the pressure- and heat-treated reaction mixture obtained is introduced directly or indirectly into a pyrolysis apparatus to carry out pyrolysis.

11. The method according to claim 10, characterized in that the pressure- and heat-treated reaction mixture, depleted of gaseous components with a boiling point lower than the temperature of the evaporation zone, is introduced directly or indirectly into a pyrolysis facility to carry out pyrolysis.

12. The method according to claim 1, characterized in that the aqueous medium contains a reaction additive selected from nitric acid, carboxylic acid, dicarboxylic acid, particularly adipic acid, tricarboxylic acid, particularly citric acid, and / or urea and / or biomaterials.

13. The method according to claim 12, characterized in that the reaction additive is a plant material.

14. The method according to claim 1, characterized in that one or more pressure barriers are arranged on the first line and / or the second line.

15. The method according to claim 1, characterized in that the reactor screw conveyor extends to the tapered end region of the reaction vessel by a corresponding taper.

16. - Water obtained after removing solids from a reaction mixture that has been pressure- and heat-treated and from which gaseous components have been removed, and / or - The water obtained from the gaseous water extracted through the water vapor extraction point, The method according to claim 1, characterized in that a reaction additive is optionally added before being added to the provided reaction mixture.

17. An apparatus for carrying out the method of claim 1, comprising a first line (10) in which a first screw conveyor (12) is disposed inside, the first line leading to a reactor (16) via a filling opening (14) designed as a pressure lock, a reactor screw conveyor (18) disposed inside the reactor (16), the reactor (16) tapering at least one end region leading to a second line (22) in which a second screw conveyor (24) is disposed via an outlet opening (20) designed as a pressure lock, the second line (22) is provided with an evaporation zone (26) that can be set to a higher temperature than inside the reactor (16), the second line (22) having a degassing section (28) in the evaporation zone (26) from which the gaseous component can be removed from the second line (22).

18. The apparatus according to claim 17, characterized in that in the second line (22), a dehydration zone (30) is located upstream of the evaporation zone (26), the temperature of the dehydration zone is higher than the boiling point of water and lower than the boiling point of nitrogen-containing components, and gaseous water can be extracted in the dehydration zone via a water vapor extraction point (32).

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