PROCESSOR AND METHOD FOR TREATING A MIXTURE OF SUBSTANCES

Description

[0001] The invention relates to a processor and a method for treating a mixture of substances.

[0002] The invention particularly relates to a method for treating a mixture of different materials, in which the mixture is mixed in a processing area of a processor under high shear forces. The processor is typically a pulper with a screw or helix. If the processor is also used to separate fine grains such as fibers, then it has a screen or perforated plate that separates an upper flow from an underflow. The invention therefore also relates to an apparatus for carrying out a method with a processor with a screw and an upper flow separated from an underflow by a screen.

[0003] A pulper, for example, can be used to separate the aluminum from multilayer packaging using high shear forces. This type of packaging is also known as composite packaging and consists of different materials such as plastics, aluminum, cardboard, and paper. Composite packaging of this type is typically manufactured by coating, lamination, or metallization. Common packaging types include blister packs, which are primarily used to package tablets. However, a mixture of different materials can also arise when shredding electrical circuits.

[0004] The best-known use for this type of composite packaging is in the food sector, where examples of juice and milk cartons, frozen food boxes, and bags for instant soup are well known. Separating the various materials in composite packaging after use during waste treatment is very difficult. The paper or cardboard portion is the easiest to separate. The composite material is soaked. The paper fibers absorb water, swell, and separate from the thin layers of polyolefins and aluminum. Polyethylene is often used as the polyolefin. After separation, the fiber is cleaned, thickened, and further processed into paper or cardboard. The paper portion or cellulose fibers in conventional composite packaging make up around 75% of the total volume. By using special chemicals, olefins and aluminum can also be separated from the fiber.

[0005] However, after separating the fibers, it is problematic to separate the remaining olefins and aluminum layer, or multiple olefin and aluminum layers. Therefore, these layers either end up unseparated in the cement industry, where the plastic component serves as an energy source and the aluminum affects the strength of the concrete made from the cement, or the aluminum is recovered in pure form in plants where the plastics are converted into gas. Attempts have also been made to separate the aluminum from the polyethylene using hot organic solvents.

[0006] Washing processes with extensive use of various chemicals make it possible to separate aluminum and olefins from the composite. However, the high chemical consumption and the difficulty of separating aluminum and olefins are problematic.

[0007] In addition to composites, there are other material mixtures that must be separated as accurately as possible for further processing. While conventional processing systems allow for separation at considerable expense, achieving acceptable purity is very difficult for many material mixtures. Composites, especially those containing aluminum and olefins, should be separated more easily.

[0008] Such a processor is described in WO 2013 / 135224 A2. EP 1 130 156 A2 shows a large inlet and outlet and no spiral for the material feed, which could lead to an increase in pressure in the container.

[0009] When the mixture of substances is mixed, especially when a washing liquid is used, foams are created which hinder processing.

[0010] The invention is therefore based on the object of further developing a generic processor and providing a method with which mixtures of substances made of different materials can be separated.

[0011] This object is achieved by a processor according to claim 1 and a method according to claim 6. Advantageous further developments are the subject of the subclaims.

[0012] The processor is suitable for all types of composite materials, regardless of the type of bonded material. Such composite materials can include plastics, metals, or paper, among others.

[0013] A cyclone not belonging to the invention has a head section with a decentralized, preferably tangential inlet and a central outlet, with an expanding outlet cone adjoining the central outlet. It is thus a double cyclone that initially narrows or remains cylindrical in the direction of flow and then expands to achieve optimal separation.

[0014] A tapered collection cone can be connected to the discharge cone. This collection cone collects fractions of the mixture to be separated by the hydrocyclone. For this purpose, a closable discharge opening is preferably connected to the discharge cone or the collection cone. In a preferred embodiment, this discharge opening is designed as a lock.

[0015] Inlet openings in the lower section of the cyclone, such as in a discharge cone or a collection cone, allow a liquid or gas to flow in. This allows the materials in the cyclone to be swirled up and fed back into the separation section of the cyclone.

[0016] To prevent material from becoming trapped in the central drain, it is proposed that the cyclone have a roof in which a central drain is arranged in such a way that it does not protrude into the cyclone. The central drain of the cyclone then has no dip tube, so that the drain can be formed in the roof of the cyclone without any protruding elements.

[0017] It has proven advantageous if the cyclone ceiling, where the outlet is located, is convexly curved or tapered toward the outlet. In a vertical cyclone, the central outlet is located at the highest point of the cyclone. This prevents particles from accumulating around the outlet in the area of the cyclone ceiling.

[0018] It has been found that such a cyclone is particularly suitable for a process that treats mixtures of substances in order to separate fractions from the mixture.

[0019] Especially for the separation of mixtures of substances which contain a composite material, such as aluminium and plastic, the cyclone has proven to be particularly advantageous as a hydrocyclone or as a cyclone operated with gas, such as air in particular.

[0020] The cyclone can be connected to the downstream section of the processor to separate sand or aluminum particles, for example, that were separated from the material in the processor. A small cyclone is sufficient for this purpose and does not need to be operated in a closed loop.

[0021] Alternatively, or in addition, another, much larger cyclone can be provided, connected to the upper flow of the processor. For this purpose, materials are removed from the upper flow, preferably using a screw conveyor, which is then treated in the cyclone and then returned to the processor above the screen.

[0022] In particular for such a large cyclone, it is proposed that the inlet of a pump be connected to the overflow discharge of the processor and an outlet of the pump be connected to the decentralized inlet of the cyclone, with the central outlet of the cyclone being connected to the overflow inlet of the processor.

[0023] It's advantageous, for example, if the pump is a centrifugal pump. A centrifugal pump can both pump large volumes and crush materials, such as wood pieces, at the same time. It thus acts like a hammer mill.

[0024] In order to maintain or influence the spiral movement in the cyclone, it is proposed that the device has a circulation pump that conveys from the central outlet of the cyclone to the decentralized inlet of the cyclone.

[0025] It is advantageous if the device has a filter whose liquid inlet is connected to the downstream of the processor and whose liquid outlet is connected to the inlet of the centrifugal pump. This allows fibers to be removed from the filter, which can also be designed as a disc filter, while the liquid is returned to the centrifugal pump circuit.

[0026] In order to pre-clean the discharge from the processor, it is proposed that the device has a further cyclone arranged between the underflow of the processor and the filter.

[0027] In addition, the device may comprise a buffer provided between the upper flow of the processor and the centrifugal pump.

[0028] The process for treating a mixture of substances can be carried out continuously. However, it is particularly advantageous if the fractions are separated from the mixture in batch operation. The mixture is passed through the hydrocyclone several times, and the various fractions separating from the mixture are gradually removed from the circuit. Thus, a predetermined quantity is treated and circulated until the fractions to be separated have been separated according to a specified time. A further quantity is then treated as the next batch. The batches can be taken from a buffer according to the first-in, first-out principle.

[0029] It is advantageous if a circuit between the central cyclone outlet and a decentralized inlet maintains, increases, or decreases the rotation in the cyclone, while a second circuit between the central cyclone outlet and the decentralized cyclone inlet is routed through a processor to separate the materials using the shear forces occurring in the processor. For this purpose, the processor is preferably operated at a high stock consistency.

[0030] When carrying out the process, it is advantageous if the aluminum layer is broken up, detached and suspended as particles in the processor by means of high shear forces and the use of chemicals.

[0031] The particles washed out in the downstream section of the processor can be further treated in a preferably single-stage hydrocyclone, particularly to separate sand-like particles. Such a hydrocyclone is simple in design, offers high efficiency, and requires little energy. Depending on the chemicals used, aluminum particles can also be removed in such a hydrocyclone. The fibers generated in the cyclone can either be separated in a disc filter or thickener or returned to the processor in the upstream section.

[0032] After completion of such a separation process, a multi-stage wash can follow, starting with highly enriched wash water and ending with quasi-fresh water.

[0033] Chemical losses are minimal in this process because the concentration differences are small (quasi-concurrent process) and thus the wash water requirement is also low.

[0034] Finally, the washed plastics can be removed from the system using a spiral scraper and the process can be restarted, i.e. the processor is loaded with new material and recycled chemicals.

[0035] During mixing of the material mixture in the work area, a portion of the mixture can be removed from the processor's work area using a screw conveyor. In a special process, after a certain processing time, the screw conveyor reverses the direction of the spiral scraper's conveying motion, thereby returning the mixture from the screw conveyor to the work area.

[0036] This results in a batch process in which a batch of material is processed in the work area until hardly any finer material is discharged through the screen and hardly any coarse material remains in the work area. The remaining material coming from the cyclone can then be enriched with the material already in the screw or spiral conveyor to improve the grinding process in the processor.

[0037] To facilitate separation of the mixture in the processor and / or cyclone, it is suggested that the separation of the fractions from the mixture be carried out in a liquid that is lighter or heavier than water. This can be achieved, for example, by adding salt or alcohol to the water. However, hydrophobic liquids such as oils can also be used.

[0038] Hydrocyclones typically separate materials with a density greater than 1. However, this can be influenced by specific flow conditions. For this purpose, a liquid, such as water, can be introduced into a tapered collection cone or discharge cone at the lower end of the hydrocyclone to create a counterflow. The liquid is preferably introduced via nozzles or inlet openings. These can be arranged in one or more planes around the circumference. The inlet flow should be dimensioned such that laminar flow promotes separation.

[0039] The invention is explained in more detail below using exemplary embodiments. Figure 1 schematically shows a device for treating composite materials with a small hydrocyclone, Figure 2 schematically shows a device for treating composite materials with a small and a large hydrocyclone, Figure 3 schematically shows a device with a washer, Figure 4 shows a processor with an inlet and outlet screw and Figure 5 shows several views of a screw with a scraper.

[0040] The Figure 1 shows the conditioner 1 with the schematically illustrated screw 2 and a sieve or perforated plate 3, which separates an area for the upper flow 4 from an area for the lower flow 5.

[0041] The processor 1 is connected to a material feed for composite materials 6. Furthermore, a microemulsion 8 and a washing emulsion 9 are added to a working area 7 in which the screw 2 is located. In the processor 1, the screw 2, microemulsion 8, composite materials 6, and washing emulsion 9 are thoroughly mixed together. The friction between the materials causes finer particles to flow off via the underflow 5, while coarser particles such as plastics are removed from the processor via the overflow.

[0042] To achieve high shear forces in the processor, which cause strong friction between the materials, a consistency of over 10% GG, preferably over 20% GG, and in practice, depending on the material, particularly preferably around 30% GG, is set in the processor. This means that a maximum of 90 kg of water is used per 10 kg of dry material mixture. Reducing the water content increases the power consumption of the spiral rotating in the processor or of the moving scrapers within the processor – however, the shear forces that cause friction between the particles increase.

[0043] To expel air from the mixture, the rotor is first stirred at a low speed of around 1 m / s at its radially outermost end. Air or gas is drawn off through a vent at the top of the processor. The processor is then continually filled with mixture until the mixture is forced into the processor. This increases the power consumption of the rotor. On the other hand, however, the shear forces also increase. It has been shown that a rotor speed of less than 5 m / s at its radially outermost end and a stock consistency of 20 to 30% GG produce optimal results in terms of material separation and power consumption.

[0044] The liquid 10 from the underflow 5 is fed to a first bath 11. The liquid from bath 16 is then fed to the processor and, after mixing with the residual chemicals still present in the plastics, is returned to the same bath 16. The same procedure is followed for baths 17 to 19.

[0045] The addition of dilution water 20 from the containers 16 to 19 into the baths 11 and 16, 17, 18, 19 results in the bath 11 still having a very highly concentrated washing emulsion, while the baths 16, 17, 18, 19 have increasingly diluted washing emulsions, so that ultimately a highly diluted washing emulsion is fed from the bath 19 via the overflow to a sewage treatment plant 21.

[0046] Fresh water 23 is added to the tank 19 for final dilution. The plastics 24 removed via the upper reaches are completely dewatered (pressed out) and are ready for further processing.

[0047] The material from the underflow 5 is pumped into a hydrocyclone 26 via a pump 25, where the aluminum is separated from the liquid 28. The fibers are entrained via the overflow 28 by flow separation and returned to the system. A sensor 29 determines the exact time the washing process begins. The mixture of aluminum and fibers is separated in tank 30 by reusing the settling aluminum 31, while the liquid 32 is added as overflow to a tank 33. From there, the liquid 34 flows to the microemulsion 8, with which it is returned to the processor 11.

[0048] The Figure 2 shows the integration of the Figure 1The processor shown or a similar processor into a device with a large hydrocyclone 40. This hydrocyclone 40 has an inlet cone 41 and a head region 42. A tangential inlet 43 and a central outlet 44 are provided in the head region. The inlet cone 41 can extend to the head region 42, so that the head region is also conical. In an alternative embodiment, the inlet cone 41 can also be cylindrical.

[0049] At the lower end of the inlet cone 41 is a smaller diameter 45, which, like a constriction, transitions from the inlet cone 41 into a widening outlet cone 46. At the lower end of the outlet cone 46, a tapered collecting cone 47 is provided, which has a discharge opening 49 closed by a lock 48.

[0050] A conditioner 50 has a screw 52 in its upper region 51 and a sieve 53 below it, which separates the upper region 51 from a lower flow 54.

[0051] The mixture 55 treated in the processor 50 is discharged by a discharge screw 56 and conveyed to a buffer 57, which can accommodate a larger quantity of the mixture to be fed as needed to a collector 58, from where the material is conveyed via a centrifugal pump 59 to the decentralized inlet 43 of the hydrocyclone 40. The collector 58 serves to dilute the circulating material with water and then feed it in liquefied form to the centrifugal pump 59. The collector 58 can therefore be designed as a screw conveyor to which liquid is added to achieve a consistency that can be conveyed via the centrifugal pump 59.

[0052] Instead of the discharge screw or discharge screw 56 and buffer 57, a particularly large discharge screw (see Figure 3) should be provided, which on the one hand makes it possible to withdraw material from the upper reaches of the processor and on the other hand to store as much material as possible, which is then gradually liquefied and fed to the centrifugal pump.

[0053] In the hydrocyclone, the material initially spirals up to the constriction 45 and from there into the outlet cone 46, where a material fraction is removed via the lock 48. The remaining material spirals back up in the outlet cone 46 into the inlet cone 41 and via the central outlet 44 back to the processor 50.

[0054] Feed openings 73 in the lower area of the cyclone allow water or another liquid to be introduced to facilitate the separation of the material in the cyclone through a radial flow component directed from the outside to the inside. For this purpose, the feed openings can be designed as nozzles that allow a liquid to enter the cyclone in a defined flow direction.

[0055] At the switch 60, the main flow curves into the line 61 and from there to the circulation pump 62. This circulation pump 62 thus pumps from the central outlet 44 of the cyclone 40 to the tangential inlet 43 of the cyclone 40.

[0056] A bypass 63, which is not absolutely necessary, makes it possible to withdraw a partial flow before the circulation pump 62 and to cut it off above the collector 58 or directly to the centrifugal pump 59.

[0057] The circuit between hydrocyclone 40, processor 50 and centrifugal pump 59 makes it possible to treat the mixture 55 over a longer period of time and to remove different fractions from the circuit at the discharge opening 49.

[0058] Once all valuable fractions have been removed, the transfer switch 64 is switched over and the lightweight material, particularly polyolefins such as polyethylene and polypropylene, is discharged.

[0059] Different plastic materials can be separated simply by selecting the liquid 65 and the hydrocyclone 40. Alternatively, the plastics can be separated after the diverter 64 in another cyclone containing a liquid that is lighter or heavier than water.

[0060] New material is added as a mixture of substances 66 either upstream of the centrifugal pump 59 to the collector 58 or at another location, such as the buffer 57.

[0061] The underflow 54 of the processor 50 is fed via a pump 67 to a small cyclone 68, where sand or, for example, aluminum 69 is separated and discharged, while the materials, such as fibers 70, are fed to a filter 71. Here, the fibers are separated, while the liquid flows via line 72 to the collector 58 and from there to the centrifugal pump 59.

[0062] The Figure 3shows a processor 100 with a spiral 101 and a scraper 102. A screen or perforated plate 103 is arranged below the scraper 102. A screw 104 is arranged on the side of the processor 100, and a vent 106 is provided on the ceiling 105 of the processor 100, which allows air to escape, particularly during the filling process. An extraction system (not shown) can be connected to this vent opening 106 in order to create a negative pressure in the processor 100. Such a vent opening prevents overpressure in the processor. Depending on the material to be treated and the washing liquid used, a vent opening may also be omitted. The fiber discharge 107 is located below the perforated plate 103, and next to it is a residue discharge 108.

[0063] A screw 104, which is suitable for an entry into the processor 100 and for a discharge from the processor 100, shows the Figure 4. There, material can be fed in via the hopper 110 and material falling out of the screw can be collected via the hopper 112.

[0064] The helix 113 of the screw 104 is arranged in a tube 114 having an opening 115. In the axial direction upstream and downstream of the opening 115, the helix 113 has an opposing pitch. The regions of the helix with opposing pitches are connected to a tube scraper 118, which slides along the inside of the tube 114 to prevent buildup. A slider 116 allows the opening to be closed.

[0065] It is advantageous if two spaced-apart openings are provided, as shown in the figure. It is advisable to position one opening for filling the processor closer to the processor than the other opening for emptying the processor. This makes it possible to easily fill and empty the processor with a single screw or helix.

[0066] The helix 113 is axially displaceable in the tube 114 in order to move it as close as possible to the scraper 150 without having to move the entire screw.

[0067] The Figure 3 The processor 100 shown is connected to a container 111 having several chambers 119 to 122 arranged one above the other. An agitator 123 has several impellers with which the liquid can be stirred in each of the chambers.

[0068] Tanks 124 and 125 allow washing liquid and washing water to be supplied to the processor.

[0069] Material to be treated can be fed via a line 126. Line 127 allows this material to be fed tangentially to the upper section of the processor.

[0070] A special dynamic and keeping the holes of a perforated sheet clear are achieved with the Figure 5 This is achieved with the scraper 150 shown. It is welded to the underside of a screw 151 and has a wall that runs essentially perpendicular to a horizontal screen surface to push the material across the screen surface. A precisely positionable slider is arranged on the underside of the scraper, allowing the slider to be guided over a perforated plate at a distance of only 1 mm. This allows the holes in the perforated plate to be brushed clean with the material to be treated.

[0071] The simplest variant for operating such a processor 100 or processors 1 and 50 is batch operation with dry material feed.

[0072] When operating in a true batch mode (filling / emptying), which is advantageous for example for processing composites without fine grain (e.g. fibers), only the processor is required.

[0073] The required liquid medium is fed into the reactor by means of a pump while the rotor is stationary.

[0074] The filling process is complete when no more air rises. At the end of the filling process, the rotor is slowly rotated at a peripheral speed of approximately 1 m / s.

[0075] The material is fed up to the power limit of drive 109 via screw 104, which serves as a reverse-running discharge system, using an attached hopper 110. The material is then forced into the processor to process as much compressed material as possible. Towards the end of the power curve (but still well before this), the processor's speed is slowly increased to the digestion speed (approximately 4 m / s). The digestion process then begins.

[0076] Finally, the washing process is initiated – preferably using a so-called differential wash. This involves taking the digestion medium from the previous batch – each with a slightly lower content of active component – from a container with a multi-chamber system (stacked vertically, each with a stirrer). If this medium is then continuously fed into the reactor, the concentration in the reactor steadily decreases with this type of wash – without the reactor having to be drained. At the end, the liquid, which is now only very slightly concentrated, is drained off and rinsed again with fresh water. If necessary, a pressing process can be inserted in between. Rinsing with fresh water reduces adhesions. Finally, the material is discharged via the discharge system.

[0077] For example, for the depletion and recovery of fiber, a batch operation with continuous underflow is suitable.

[0078] When operating with dry material feed, only the reactor is required as a component. The water feed is at the very top – tangentially, to utilize the feed momentum as a turbine effect.

[0079] To fill the reactor, the material is fed through hopper 110 of the discharge system, with simultaneous fiber pulping and fiber washing. This process step continues until approximately half of the fiber content has been removed—measured by pulp consistency and water flow in the underflow.

[0080] Subsequently, the washed-out accompanying material is added, and the spiral is allowed to continue running until there is so little fiber left in the reactor that further washing would be uneconomical. This would be uneconomical both in terms of fiber recovery and washing for plastics production.

[0081] Finally, the reactor is emptied completely using a discharge system.

[0082] Another variant involves the addition of a suspension, i.e., a liquid feed. This process is similar to the previously described procedure. However, the material is fed via a pump through the tangential inlet – e.g., a centrifugal pump.

[0083] This process has the advantage, among other things, that the material and water are mixed beforehand, significantly accelerating the washing process. It also makes it possible to separate out unwanted heavy particles beforehand—e.g., using a cyclone. The suspension unit can also pre-break large particles, potentially replacing a pre-shredder. Furthermore, due to the interaction of the screw conveyor and the suction centrifugal pump, such a system is much more powerful than the discharge screw, which in practice must press into a high structural pressure for several minutes.

[0084] The material is fed in again until about half of the fiber content has been removed - measured by the pulp density and water flow in the downstream section.

[0085] In contrast to the dry material feed, the remaining fiber is removed by running the full accompanying material spiral backwards.

[0086] The subsequent emptying continues until the power requirement of the spiral decreases. This ensures that the discharge buffer is still (almost) full—full of washed accompanying substances. Then the next batch can begin.

[0087] The Figure 2 The batch operation with an external buffer shown here is by far the most powerful variant, but also the most complex. An external buffer is required here. This ensures that the maximum possible fiber input—and thus the highest fiber flow—is achieved at any time during a batch.

[0088] By comparison, in batch operation, approximately halfway through the fiber recovery time (before the material feed changes), material with full fiber content is forced into material with no fiber content, and then material with no fiber content is mixed into material with a still significant fiber content. Both processes generate a significant amount of entropy.

[0089] The process itself: The completely empty system is filled with suspension, then circulated until the desired residual fiber content is reached. It is then emptied into the reject buffer via a diverter, and from there, it is fed into the reject press.

Claims

1. A conditioner with a container, in which a screw (2, 52) is arranged, and a spiral leading into the container, characterized in that the container is closed in a pressure-tight manner and has a venting opening (106) on its upper side, which is arranged on the ceiling (105) of the preparator (100) in the lid in order to allow air to escape, in particular during the filling process.

2. The conditioner according to claim 1, characterized in that it has a suction appliance which is connected to the venting opening (106).

3. The conditioner according to one of the preceding claims, characterized in that the spiral (113) is axially displaceable in order to be brought close to the scraper (150).

4. The conditioner according to one of the preceding claims, characterized in that the spiral (113) is arranged in a tube (114) which has an opening (115) (115), wherein the spiral (113) is arranged before and after the opening (115) in the axial direction and has an opposite pitch before the opening (115) compared to after the opening (115).

5. The conditioner according to claim 4, characterized in that the spiral (113) has no core and has a pipe scraper (118) between the areas with opposing pitches connecting these spiral areas.

6. A method for processing a substance mixture (6, 66) of different materials with a conditioner according to one of the preceding claims, in which a washing liquid is added to the substance mixture and the substance mixture (6, 66) is mixed in a work area of the conditioner (1, 50) by means of a rotor under high shear forces in order to separate at least one fraction from the mixture, characterized in that the separation of the fractions from the mixture (6, 66) is carried out in a liquid (65) which is lighter or heavier than water.

7. The method according to one of the preceding method claims, characterized in that during mixing the speed of the rotor at its radially outermost end is less than 5 m / s.

8. The method according to one of the preceding method claims with a cyclone, where the substance mixture (6, 66) is mixed in a work area of the conditioner (1, 50) under high shear forces in order to separate at least one fraction from the mixture, characterized in that this fraction is subsequently further treated in the cyclone.

9. The method according to one of the preceding method claims, characterized in that the substance mixture is fed to and removed from the conditioner using the same spiral conveyor.

10. The method according to one of the preceding method claims, characterized in that after separation of a fraction of the substance mixture in the work area, a part of the mixture is removed from the work area of the conditioner by a spiral conveyor and after a certain processing time, a mixture is conveyed from the spiral conveyor back into the work area by reversing the conveying direction of the screw.

11. The method according to one of the preceding method claims, characterized in that the washing liquid is stored in containers with different washing liquid concentrations and the conditioner is gradually supplied with liquid of decreasing concentration from the containers.