Apparatus and method for thermal decomposition of organic raw materials

Abstract

The present invention relates to a system for pyrolysis of waste materials, particularly for depolymerizing shredded scrap tire material, to produce a raw material that can be further processed into recovered carbon black. The system includes at least one rotary tube reactor, a quench unit, and a burner unit. The rotary tube reactor has a reactor drum that rotates about a longitudinal axis during operation, and the reactor drum has an internal chamber that has at least one heating zone, a reaction zone, and a degassing zone. The burner unit is configured to combust pyrolysis gas into heating gas and generate a heating gas flow through the heating jacket chamber, and is connected to the heating jacket casing via a heating gas supply line. The quench unit is connected to the gas outlet of the rotary tube reactor and is configured to cool the pyrolysis gas generated in the reactor internal chamber during operation. According to the present invention, multiple heating gas outlet flaps are distributed along the length of the heating jacket casing, and the heating gas outlet flaps can influence the flow of heating gas through the heating jacket chamber so as to supply different amounts of heat to the heating zone, reaction zone, and degassing zone within the reactor internal chamber, respectively. This system allows for persistently stable (static) process conditions to be achieved in continuous pyrolysis operation, enabling the production of pyrolysis solids from, for example, shredded waste tire material, with a starting quality that meets all requirements for further processing in a back-end system to produce a refined form of recovered carbon black.

Description

Technical Field

[0006] , , , , ,

[0005] ,

[0007] , ,

[0001] The present invention relates to an apparatus and method for pyrolyzing organic raw materials.

[0002] Pyrolysis generally means the thermal decomposition of organic compounds. In this case, under the exclusion of oxygen and, for example, at a high temperature of 300 °C to 900 °C, the bonds within the relatively large molecules of the raw material are forcibly broken. By pyrolyzing the solid raw material, gases, liquids, and solids are usually obtained, and in this case, the gases and liquids are separated from the pyrolysis vapor generated during pyrolysis. At that time, the quantitative ratio and composition depend on the raw material, pyrolysis temperature, pressure ratio, and reaction time. When pyrolyzing polymers, often the corresponding monomers occur as part of the pyrolysis vapor.

[0003] Apparatuses and methods for pyrolyzing organic raw materials are basically known.

[0004] For example, according to European Patent No. 0592057, a method for pyrolyzing waste tires is known, in which the waste tires are pyrolyzed in a metal bath under the interruption of air and water and under reduced pressure. The pyrolysis vapor generated by pyrolysis is separated into the gas phase or the liquid phase after cooling. In this method, it is further assumed that a part of the gas phase is then returned to the inner chamber of the reactor above the metal bath, and nitrogen is continuously introduced into the inner chamber of the reactor above the metal bath. In the method known from this publication, the pyrolysis reaction is controlled, inter alia, by controlling the velocity of the gas flow in the inner chamber of the reactor.

[0005] A method for carrying out pyrolysis in a rotary tube reactor in a continuous process is known from German Patent Application Publication No. 102014015281.

[0006] An important product that can be obtained by pyrolyzing waste tires is char, especially high-value char called "carbon black" having a large specific surface area.

[0007] The process carried out continuously for the depolymerization or thermal decomposition of waste rubber in order to produce a material suitable for further processing to obtain recovered carbon black must be carried out as follows: 1. The reaction temperature and heat of reaction achieve depolymerization of the rubber component, but further decomposition of hydrocarbons down to carbon is avoided. 2. The conditions in the reactor after the completion of the reaction stage (reaction zone) ensure that hydrocarbon residues are almost completely removed from the remaining solid flow, and 3. High-temperature gaseous decomposition products are rapidly removed from the reactor chamber at the point of generation and rapidly cooled to prevent recombination (repolymerization) of the decomposition products, and consequently, the generation of high-boiling-point components and their deposition on solids.

[0008] Materials resulting from pyrolysis processes suitable for further processing to obtain recovered carbon black are particularly favorable in that the proportion of extractable material with toluene is less than 1%, preferably less than 0.5%, of oil content. Furthermore, the morphology of the carbon particles is important for intended use as a filler in rubber and plastic applications. Carbon additionally formed during pyrolysis does not possess the morphological properties of conventional carbon black and degrades the quality of the final product. The proportion of oil carbon, also referred to as "char," should preferably not exceed 2% of the total carbon.

[0009] The fundamental technical problem underlying this invention is to provide an improved apparatus for the continuous thermal decomposition of organic raw materials.

[0010] According to the present invention, a system for thermally decomposing waste materials, particularly a system for depolymerizing shredded waste tire material, is proposed to produce raw materials that can be further processed to obtain recovered carbon black. The system comprises at least one rotary tube reactor, a quenching unit, and a burner unit.

[0011] A rotary-tube reactor has a reactor drum that rotates around a longitudinal axis during operation, and this reactor drum has drum walls surrounding the reactor chamber. A conveying device is arranged on the inner surface of the drum walls to transport the waste material to be processed as the reactor drum rotates. The reactor chamber has at least one heating zone, a reaction zone, and a degassing zone. The reactor drum has a waste material inlet, as well as a (thermal decomposition) solid outlet and a (thermal decomposition) gas outlet. The reactor drum is surrounded by a heating jacket casing and is rotatably supported so that the reactor drum can rotate around its axis of rotation inside the heating jacket casing. The heating jacket casing encloses a heating jacket chamber, which is defined internally by the drum walls of the reactor drum.

[0012] The burner unit is configured to burn a gas (preferably a pyrolysis gas) to produce a heating gas, and to generate a flow of heating gas that passes through the heating jacket chamber. For this purpose, it is connected to the heating jacket casing via a heating gas pipeline so that the heating gas can be introduced into the heating jacket chamber, thereby indirectly heating the reactor drum located inside the heating jacket chamber from the outside with the heating gas.

[0013] The quenching unit is connected to the gas outlet of the rotary tube reactor and is configured to cool the pyrolysis gases produced in the reactor chamber during operation.

[0014] According to the present invention, a plurality of heating gas outlet flaps are distributed along the length of the heating jacket casing, and the heating gas outlet flaps can influence the flow of heating gas through the heating jacket chamber so that different amounts of heat can be supplied to the heating zone, reaction zone, and degassing zone within the reactor chamber, respectively.

[0015] Preferably, the conveying device is a conveying spiral formed by guide plates or guide projections that extend along a single helical track and project from the drum wall toward the interior of the reactor chamber.

[0016] Preferably, the spiral grooves of the conveying spiral have different pitches in the reaction zone and the degassing zone, thereby optimizing the residence time of the pyrolysis product in the different zones.

[0017] The underlying principles of this invention, including the recognition of specific process conditions and the structural characteristics of the system components, provide a solution that, on the one hand, further improves the efficiency of the method when using the system for the thermal decomposition of waste tires / waste rubber, and on the other hand, guarantees the required quality of the thermal decomposition products.

[0018] This invention acknowledges that, unlike batch-type (intermittent) pyrolysis processes, continuously operating systems present special challenges in ensuring high process stability and consistent product quality over long operating periods. This requires a finely adapted (tuned) process mode for the entire system, consisting of a rotary-tube reactor, a quenching unit, and a burner system. A further problem for sustainably stable process implementation is the risk of solid particles, carried by high-temperature decomposition gases, accumulating in the transition area from the reactor chamber to the quenching unit, ultimately clogging the piping between the reactor and the quenching unit.

[0019] The system and method according to the present invention allow the residence time of pyrolysis products in individual zones within the reactor chamber to be adapted so that each process, such as heating, decomposition reaction (pyrolysis / depolymerization), and residual degassing, proceeds completely and zone by zone at a predetermined rotational speed of the reactor drum and a predetermined processing rate of pyrolysis products. For this purpose, the conveying spirals within the reactor drum have different pitches for each zone. The drum diameter and the spacing between the spiral grooves of the conveying spirals in each longitudinal section of the reactor drum are also selected for each zone so that the bulk volume and mixing of the bulk material are sufficient for the process proceeding in each zone. In addition to good heat transfer from the reactor jacket chamber to the drum wall and from the drum wall to the pyrolysis products, good mixing of the solid bulk material is necessary for sufficient mass transfer and heat transfer. Mixing is achieved by lifting blades positioned within the spiral grooves.

[0020] The rotation of the reactor drum and the movement of materials within the reactor drum cause some of the solid to be stirred up and discharged along with the high-temperature decomposition gas. A drawback of conventional reactor structures was the placement of the gas outlet at the end of the reactor drum. As a result, the solid (dust-like) stirred up in the degassing zone was carried away and discharged by the separation gas produced in the reaction zone. To avoid this problem, it is preferable to provide a pyrolysis gas outlet pipe that can directly extract the separation gas from the reaction zone and lead it to a quenching unit. A pyrolysis gas outlet pipe that enters the reactor drum from the outlet side, passes through the degassing zone, and reaches the end of the reaction zone has been proven to be an effective means of solving this drawback. At the same time, such a means allows the decomposition products to leave the reactor chamber more quickly, thus avoiding the aforementioned drawbacks (recombination and additional formation of decomposed carbon), and thus ensuring an improvement in the quality of the recovered carbon black.

[0021] Complete removal of solids from the gas phase is impossible even by the means described above. Over time, coke-like compounds and carbon dust accumulate in the pyrolysis gas outlet tube between the quenching unit and the reactor chamber. Their removal is achieved by a tube cleaning device operated at regular intervals (e.g., twice a week). During the tube cleaning process, the pyrolysis process is briefly interrupted by withholding material supply to interrupt the formation of decomposition gases. The tube cleaning device is characterized by a cleaning member, filled to the entire diameter of the pyrolysis gas outlet tube, being guided by a rack through the pyrolysis gas outlet tube—starting from the quenching unit inlet and reaching the tube end inside the reactor drum—in which case the deposits are removed and transported to the inlet opening of the pyrolysis gas outlet tube, and thus into the reaction zone of the reactor drum. The rack is then moved backward again with the cleaning member, and thus completely removed from the pyrolysis gas outlet tube. The rack is driven by a drive unit equipped with a gear motor and gears. The rack, cleaning member, and drive gear are located in a closed tubular member that is positioned directly opposite the pyrolysis gas outlet pipe in the resting position.

[0022] For efficient operation of the pyrolysis reactor, an assembly configuration in which the burner system supplies heating gas to two rotating tube reactors has been demonstrated to be effective. The heating gas produced by the combustion of pyrolysis gas with air in the burner chamber reaches a temperature of 850°C. This heating gas is mixed with the heating gas that has already been used and recycled in a mixing section, thereby obtaining the required heating gas temperature of 580-680°C and providing a large volume flow of heating gas. The controlled heat supply to each reactor is achieved by a heating gas inlet flap at the lower inlet on the inflow side leading to the heating jacket chamber of the rotating tube reactor.

[0023] The heat distribution along the longitudinal direction of the reactor drum is achieved by heating gas outlet flaps positioned above the heating jacket casing, which distribute heat along the length of the heating jacket casing, with each degree of opening of these heating gas outlet flaps ensuring the heat demand of each reactor zone. To adjust the optimal heat distribution, it is advantageous that the adjustment (opening) of the heating gas outlet flaps is highly adjustable and coordinated with each other. A suitable flap adjustment structure demonstrated with respect to the tire section results in a distribution of the supplied heat of 20% for the heating zone of the reactor drum, 70% for the reaction zone, and 10% for the degassing zone. The spent heating gas arriving through the heating gas outlet flaps of both heating jacket casings flows into a collection pipeline for heating gas recirculation and is typically at a temperature of 550°C.

[0024] In the mixing section, the heated gas generated from the recirculated heated gas and the fresh heated gas from the burner unit, which is not needed for heating the reactor, can be supplied for further heat utilization as a heat transfer medium, and subsequently, flue gas purification can be performed if necessary.

[0025] On the one hand, the heat distribution obtained by this configuration offers advantages, and on the other hand, it can compensate for fluctuations and disturbances in the reactor process without using primary energy in the form of natural gas or liquefied gas for the burner unit. Such disturbances in the process could be, for example, the periodic operation of the pipe cleaning device described above. The pyrolysis gas (synthesis gas; the uncondensed portion of the decomposition products) supplied by the induced fan of the quenching unit is completely burned in the burner unit.

[0026] The pyrolysis gas has a temperature of typically 40°C at the quench outlet. In the process of one reactor, fluctuations occur. When the demand for heat for pyrolysis increases, the quench outlet temperature of the pyrolysis gas can be increased by changing the quench operating parameters. Thereby, the amount of pyrolysis gas around a predetermined component in the decomposition gas increases. Otherwise, this component would have condensed in liquid form and been present in the pyrolysis oil. The pressure adjustment of the internal pressure of the reactor to a value in the range of an overpressure of 50 - 150 Pa (an overpressure of 0.5 - 1.5 mbar) is achieved by the suction fan of the quench unit. Thereby, in response to fluctuations in the amount of pyrolysis gas generated, the conveying amount is adapted in the suction fan, and the pyrolysis gas of the burner unit is supplied at a supply overpressure of 2000 - 6000 Pa (an overpressure of 20 - 60 mbar).

[0027] Embodiments and further aspects of the present invention will be described in detail with reference to the drawings.

Brief Description of the Drawings

[0028] [Figure 1] It is a diagram showing a system for pyrolyzing waste materials, particularly for pyrolyzing tire pieces. [Figure 2] It is a longitudinal sectional view of a rotary tube reactor according to the present invention. [Figure 3] It is a diagram showing an apparatus for the post-treatment of pyrolysis solids. [Figure 4] It is a diagram showing an apparatus for solid preliminary purification as part of the apparatus for the post-treatment of pyrolysis solids in FIG. 3. [Figure 5] It is a diagram showing a fine pulverization apparatus of the apparatus for the post-treatment of pyrolysis solids in FIG. 3. [Figure 6] It is a diagram showing a whitening apparatus of the apparatus for the post-treatment of pyrolysis solids in FIG. 3. [Figure 7] It is a diagram showing a drying part and a packaging apparatus of the apparatus for the post-treatment of pyrolysis solids in FIG. 3.

[0029] The waste material thermal decomposition system 10 according to the present invention includes a burner unit 12, one or more rotary tube reactors 14, and one or more quenching units 16; see Figure 1.

[0030] The rotary tube reactor 14 has a reactor drum 18 that is rotatably positioned within a heating jacket casing 20 around a rotation axis.

[0031] The reactor drum 18 has a waste material inlet 22 at one of its longitudinal ends and a pyrolysis solid outlet 24 at the other longitudinal end. Furthermore, the reactor drum 18 is connected to a pyrolysis gas outlet 26. The reactor drum 18 surrounds the reactor chamber 28, which forms a heating zone 30, a reaction zone 32, and a degassing zone 34. The reactor chamber 28 is surrounded by a drum wall 36, and the drum wall itself is also surrounded by a heating jacket casing 20, so a heating jacket chamber 38 is created between the heating jacket casing 20 and the drum wall 36, into which a heating gas can be introduced.

[0032] The heating gas for heating the reactor drum 18 and its contents is generated by the burner unit 12. The heating gas is guided from the burner unit 12 to the heating gas inlet 42 within the heating jacket casing 20 via the heating gas supply pipeline 40. The heating gas inlet 42 is located near and below the waste material inlet 22. Above the reactor drum 18, the heating jacket chamber 38 has a plurality of heating gas outlet flaps 44 distributed along the longitudinal axis of the reactor drum 18, the degree of opening of these heating gas outlet flaps is adjustable and controllable. Therefore, the heating gas flowing into the heating jacket chamber 38 through the heating gas inlet 42 can flow around the drum wall 36 towards the heating gas outlet flaps 44, thus heating the reactor drum 18 and its contents from the outside.

[0033] By adjusting and, if applicable, controlling the degree of opening of each heating gas outlet flap 44, the temperature distribution within the heating jacket chamber 38, and consequently the temperature distribution within the reactor chamber 28, can be controlled and adjusted. In this way, suitable temperatures can be adjusted, particularly for the heating zone 30, reaction zone 32, and degassing zone 34 within the reactor drum 18.

[0034] The heated gas flowing out of the heating jacket chamber 38 through the heated gas outlet flap 44 is returned via the heated gas recirculation pipeline 46 and can be mixed with the heated gas generated by the burner unit 12.

[0035] For efficient operation of the pyrolysis reactor, an assembly configuration in which the burner unit 12 supplies heating gas to two rotary tube reactors 14 has been demonstrated to be effective. The heating gas generated from the burner unit 12 by the combustion of pyrolysis gas with air reaches a temperature of 850°C. This heating gas is mixed with the heating gas that has already been used and recycled in the heating gas mixing section 48, thereby obtaining the required heating gas temperature of 580-680°C and providing a large volume flow of heating gas.

[0036] The controlled heat supply to each rotary-tube reactor 14 is achieved by a heating gas inlet flap 50 at the lower heating gas inlet 42 on the inflow side leading to the heating jacket chamber 38 of the rotary-tube reactor 14. Heat distribution along the length of the reactor drum 18 is achieved by heating gas outlet flaps 44 distributed upward along its length along the heating jacket casing, and the degree of opening of each of these heating gas outlet flaps ensures the heat demand of each reactor zone 30, 32, and 34. To adjust the optimal heat distribution, it is advantageous that the adjustment (degree of opening) of the heating gas outlet flaps 44 is highly adjustable and coordinated with one another. A suitable flap adjustment structure demonstrated with respect to the tire section results in a distribution of the supplied heat of 20% for the heating zone 30 of the reactor drum 18, 70% for the reaction zone 32, and 10% for the degassing zone 34.

[0037] The used heating gas, arriving through the heating gas outlet flaps 44 of both heating jacket casings 20, flows into a recirculation manifold 46 and typically has a temperature of 550°C. In the heating gas mixing section 48, heating gas not required for heating the rotary-tube reactor 14, resulting from the recirculated heating gas and fresh heating gas from the burner unit 12, can be supplied for further thermal utilization as a heat transfer medium and subsequently, optionally, for flue gas purification. Advantages are obtained, on the one hand, from the heat distribution achieved by this configuration, and on the other hand, from the ability to compensate for fluctuations and disturbances in the reactor process without using primary energy in the form of natural gas or liquefied gas for the burner unit 12.

[0038] Therefore, preferably, the burner unit 12 is connected to two rotary-tube reactors 14, so that the heating gas is guided to both rotary-tube reactors 14 via two heating gas supply lines (each of which leads to one rotary-tube reactor), and the heating gas flowing out from each heating jacket casing 20 can also be returned via a common heating gas recirculation line 46 located above and midway between the two rotary-tube reactors.

[0039] Further improvements to the pyrolysis process can be achieved—either as an alternative to or supplement to the temperature control described above—by the structure of the reactor drum, which allows for appropriate residence times of the pyrolysis products in individual zones 30, 32, and 34 within the reactor drum. The residence times are structurally adjusted so that each process, for example, heating in heating zone 30, decomposition reaction or pyrolysis or depolymerization in reaction zone 32, and residual degassing in degassing zone 34, proceeds completely and zone by zone at a predetermined rotational speed of the reactor drum 18 and a predetermined processing rate of the pyrolysis products.

[0040] The transport of pyrolysis products from the waste material inlet 22 to the pyrolysis solid outlet 24 along the longitudinal direction of the reactor drum 18 is carried out by transport spirals 52 located inside the reactor drum 18 and projecting inward from the drum wall 36; see Figure 2. The transport spirals 52 inside the reactor drum 18 have different pitches in each zone. Thus, the transport spiral 52.1 in the heating zone 30 has a different pitch than the transport spiral 52.2 in the reaction zone 32 or the transport spiral 52.3 in the degassing zone 34. Furthermore, the reactor drum 18 has varying drum diameters along its longitudinal axis. The drum diameter is largest in the reaction zone 32. The spacing between the spirals of the individual transport spirals 52.1, 52.2 and 52.3 is also not the same in all three zones. Rather, the diameter of each drum of the reactor drum 18 and the spacing between the spirals of the conveying spiral 52 are sized such that, for each of the three zones, the desired bulk and mixing of the pyrolysis product is sufficient for the process that proceeds each time, namely heating, decomposition reaction, and residual degassing.

[0041] In addition to good heat transfer from the heating jacket chamber 38 to the drum wall 36 and from the drum wall 36 to the pyrolysis product in the reactor chamber 28, good mixing of solid bulk materials from the pyrolysis product is necessary for sufficient mass transfer and heat transfer. Mixing is achieved by lifting blades 54 positioned within the helical grooves of the conveying spiral 52.

[0042] During the operation of the rotary-tube reactor 14, waste materials, such as tire shavings, are supplied as pyrolysis products through the waste material inlet 22 of the reactor drum 18. For this purpose, a supply screw conveyor 56 operates to transport the waste materials from the waste material inlet 22 into the reactor drum 18. Inside the reactor drum 18, the waste materials are transported from a transport spiral 52.1 to the heating zone 30, where they are mixed by a lifting blade 54. The pyrolysis products, i.e., waste tire shavings, are then transported in the reaction zone 32 by a transport spiral 52.2 to the degassing zone 34. In the degassing zone 34, the pyrolysis products are then transported by a transport spiral 52.3, which has a larger pitch and therefore a higher transport speed, to the pyrolysis solids outlet 24. At the pyrolysis solids outlet 24, the pyrolysis solids produced in the reactor drum 18 fall into a collection slot 58 and are discharged from the collection slot by an outlet screw conveyor 60.

[0043] The pyrolysis gas generated during pyrolysis can flow out of the reactor chamber 28 through the pyrolysis gas outlet pipe 62. Advantageously, the pyrolysis gas outlet pipe 62 extends from the pyrolysis gas outlet 26 into the reaction zone 32. The pyrolysis gas outlet pipe 62 extends to the center of the reactor drum 18 along the rotation axis of the reactor drum 18, in which case the pyrolysis gas outlet pipe 62 does not need to be precisely aligned with the rotation axis of the reactor drum 18. The pyrolysis gas generated in the reactor chamber 28 during pyrolysis can flow in through the inlet opening 64 of the pyrolysis gas outlet pipe and flow through the pyrolysis gas outlet pipe 62, which penetrates the pyrolysis gas outlet 26, to the quenching unit 16. In this case, the inlet opening 64 of the pyrolysis gas outlet pipe 62 is located in the region of the reaction zone 32, as already mentioned. This effectively prevents solid particles, which are generally dusty and are stirred up in the degassing zone 34, from being carried out of the reactor chamber 28 through the pyrolysis gas outlet 26 by the pyrolysis gas generated in the reaction zone 32 and discharged outside. A further advantage of the pyrolysis gas outlet pipe 62, which extends into the reaction zone 32, is that the decomposition products, i.e., the pyrolysis gases, generated during pyrolysis can flow out of the reactor chamber 28 more quickly, avoiding drawbacks such as the recombination of decomposition products and the additional formation of decomposed carbon. In this way, the quality of the recovered carbon black is further improved.

[0044] Within the rapid cooling unit 16, the pyrolysis gas flowing out from the pyrolysis gas outlet pipe 62 is cooled, causing it to liquefy at a relatively high evaporation temperature and become pyrolysis oil. The liquid—pyrolysis oil—generated within the rapid cooling unit 16 is collected in a collection container 66 at the lower end of the rapid cooling unit 16 and discharged by a pump 68. A portion of the pyrolysis oil flows through the pyrolysis oil recirculation pipe 70 and the liquid cooler 72, returning to the rapid cooling unit 16, where it is sprayed by the spray unit 74. If the pyrolysis oil generated in the rapid cooling unit is not recirculated, it is discharged through the liquid outlet 76. The unliquefied pyrolysis gas remaining within the rapid cooling unit 16 is ultimately supplied to the burner unit 12 via the pyrolysis gas pipe 78, where it is burned and becomes heated gas.

[0045] The pyrolysis gas supplied from the quenching unit 16 is synthesis gas formed by the proportion of uncondensed pyrolysis decomposition products. The pyrolysis gas typically has a temperature of 40°C at the outlet of the quenching unit 16. If fluctuations occur in the process of one or both rotary-tube reactors 14, and the demand for heat for pyrolysis increases, the quenching outlet temperature of the pyrolysis gas can be increased by changing the operating parameter values ​​of the quenching unit 16. This also increases the amount of pyrolysis gas surrounding a certain component in the decomposition gas. Otherwise, this certain component would have liquefied within the quenching unit 16 and condensed into a liquid state in the pyrolysis oil.

[0046] For adjusting and controlling process parameters, the burner unit 12 is connected to the burner control unit 100, which allows the air supply to the burner unit 12 to be controlled by closed-loop control via the fan 102. The gas supply control unit 104 controls the amount of pyrolysis gas to be supplied to the burner unit 12 via the gas supply valve 106.

[0047] The amount of recirculated heated gas to be supplied to the heated gas mixing section 48 is controlled in a closed loop by a recirculation control unit 108 that controls the recirculated heated gas fan 110.

[0048] To control the rapid cooling outlet temperature in a closed loop, a rapid cooling temperature control unit 112 is provided that controls the pyrolysis oil circulation valve 114. This allows control of the amount of cooled pyrolysis oil sprayed into the rapid cooling unit 16. As described above, the circulating pyrolysis oil is cooled by the water cooler, so the rapid cooling outlet temperature can be controlled by the amount of pyrolysis oil returned.

[0049] Furthermore, each rotary tube reactor 14 is provided with an additional process control unit 116 that controls an induction fan 94.

[0050] The rotary tube reactor 14 is operated by an internal pressure in the reactor chamber 28 that is approximately 50 Pa to 150 Pa above the ambient pressure. This overpressure is achieved via the induced fan 94 of the quenching unit 16. By adjusting the feed rate in the induced fan 94, it is possible to react to fluctuations in the amount of pyrolysis gas produced. The pyrolysis gas is supplied by a supply overpressure that is 2000 Pa to 6000 Pa above the ambient pressure.

[0051] Even though the pyrolysis gas outlet pipe 62 extends into the reaction zone 32, it is impossible to completely remove solids from the pyrolysis gas. Therefore, over time, coke-like compounds and carbon dust accumulate inside the pyrolysis gas outlet pipe 62. To remove such deposits, a pipe cleaning device 80 is provided, which can be used at regular intervals, for example, twice a week. The pipe cleaning device 80 has a cleaning member 82, the outer diameter of which corresponds to the inner diameter of the pyrolysis gas outlet pipe 62. The cleaning member 82 can be moved into the pyrolysis gas outlet pipe 62 by a rack 84 until it reaches the inlet opening 64 of the pyrolysis gas outlet pipe 62. This removes the deposits in the pyrolysis gas outlet pipe 62, which are then transported to the inlet opening 64, thus reaching the reaction zone 32 of the reactor drum 18 again. The cleaning member 82 can then be moved back by the rack 84, completely removing it from the pyrolysis gas outlet pipe 62. A drive unit 86 is provided to drive the rack 84, which includes a gear motor 88 and a drive gear 90. In its resting position, the rack 84, cleaning member 82, and drive gear 90 are located within a closed pipe member 92 that is positioned directly opposite the outlet side of the pyrolysis gas outlet pipe 62.

[0052] When using the pipe cleaning device 80, the pyrolysis process is briefly interrupted by not supplying waste material to the reactor drum 18 in order to interrupt the formation of pyrolysis gas.

[0053] This constitutes a disturbance in the pyrolysis process, and the result can be reduced by appropriately adjusting the heating gas outlet flap 44. Additionally, the results related to uniform operation can be minimized by adjusting the operating conditions of the quenching device 16, as described above.

[0054] For post-treatment of the pyrolysis solids that exit the reactor drum 18 via the pyrolysis solid outlet 24, the apparatus shown in Figure 3, also known as the backend, is provided.

[0055] The pyrolysis solid discharged from the reactor drum 18 is first subjected to solid pre-purification; see Figure 4. For this purpose, a device 120 is provided for magnetically removing coarse components from the pyrolysis solid. The pyrolysis solid, free of coarse magnetic components, is then fed to a device 122 for coarse crushing of the pyrolysis solid. This device 122 crushes the pyrolysis solid into particles smaller than 2 mm. The coarsely crushed pyrolysis solid is then fed again to a second device 124 for removing magnetic components. This device 124 removes extremely fine magnetic components. The magnetic components removed by devices 120 and 124 may be fed to a steel press, respectively.

[0056] The pyrolysis solid, free from fine magnetic components, is finally fed to a device 106 for removing coarse and fibrous components. The thus pre-purified pyrolysis solid is then fed to a fine grinding section, for example, a jet grinder 130 as shown in Figure 5. The jet grinder 130 has a jet grinding device equipped with a classifier wheel 132, which functions for grinding and classifying the pyrolysis solid and maintaining an upper particle size limit of, for example, 15 μm. Alternatively, a roller mill may be used in cooperation with a classifier wheel for particle classification.

[0057] The pulverized pyrolysis solid is finally fed into a stirring vessel 134, which functions to remove air from the pulverized pyrolysis solid, thereby obtaining a uniform and increased bulk density for subsequent polishing.

[0058] For the purpose of refining, a refining apparatus 140, as shown in Figure 6, is provided. The refining apparatus 140 includes a pin mixer and a metering device for supplying the powder and a water-surfactant mixture.

[0059] After exiting the polishing unit 140, the polished pyrolysis solid is supplied to the drying unit 150; see Figure 7. The drying unit is equipped with a drum dryer or a fluidized bed dryer for evaporating the polishing water. The heat required for the drying unit 150 is preferably provided, at least partially by the system 10, in the form of heat supplied to a heat transfer medium via the heating gas outlet pipe 126 from the amount of heating gas taken from the excess heating gas in the recirculation pipe 46; see also reference numeral 126 in Figure 1.

[0060] After drying the refined pyrolysis solid, sieving is performed to separate large and small particles from the product stream. The large and small particles are then fed into the fine grinding process 130.

[0061] Finally, the refined and classified pyrolysis solid can be packaged using the packaging device 160. [Explanation of Symbols]

[0062] 10 Systems 12 burner units 14. Rotary tube reactor 16 Rapid Cooling Unit 18 Reactor Drum 20 Heated jacket casing 22 Waste material entrance 24 Pyrolysis solids outlet 26 Pyrolysis gas outlet 28 Reactor interior 30 heating zones 32 reaction zones 34 Degassing Zone 36 Drum Wall 38 Heating Jacket Chamber 40. Heating gas supply pipeline 42 Heating gas inlet 44. Heated gas outlet flap 46. ​​Recirculation pipeline for heated gas 48. Heated gas mixing section 50 Heating gas inlet flap 52 Conveyor spiral 54 Lifting Blades 56 Supply screw conveyor 58 collection slots 60. Lead-out screw conveyor 62 Pyrolysis gas outlet pipe 64 Entrance opening 66 Collection container 68 pumps 70 Pyrolysis oil recirculation line 72 Liquid cooler 74 Spray Unit 76 Liquid outlet 78 Pyrolysis gas pipeline 80 Pipe cleaning device 82 Cleaning parts 84 racks 86 Drive Unit 88 Gear Motor 90 drive gear 92 Pipe members 94 Inducing Fan 100 Burner Control Unit 102 Fans 104 Gas supply control unit 106 Gas supply valve 108 Recirculation Control Unit 110 Recirculating heating gas fan 112 Rapid Cooling Temperature Control Unit 114 Pyrolysis oil circulation valve 116 Process Control Unit 120 Apparatus for magnetically removing coarse components 122 Apparatus for crushing pyrolysis solids 124 Second apparatus for removing magnetic components 126 Heated gas outlet 130 Fine grinder 132 Jet pulverizer 134 Stirring vessel 140 Polishing equipment 150 Drying section 160 Packaging equipment

Claims

1. A system (10) for thermally decomposing waste materials, the system (10) includes at least one rotary tube reactor (14), a quenching unit (16), and a burner unit (12), The rotary tube reactor (14) has a reactor drum (18) that rotates around its longitudinal axis during operation, and the reactor drum (18) has drum walls (36) surrounding the reactor chamber (28). A conveying device (52) is positioned on the inner surface of the drum wall (36) to transport the waste material to be processed as the reactor drum (18) rotates. The reactor chamber (28) has at least one heating zone (30), a reaction zone (32), and a degassing zone (34), The reactor drum (18) has a waste material inlet (22), a pyrolysis solid outlet (24), and a pyrolysis gas outlet (26), and is surrounded by a heating jacket casing (20) and is rotatably supported, so that the reactor drum (18) can rotate inside the heating jacket casing (20) about its axis of rotation, the heating jacket casing (20) encloses a heating jacket chamber (38), the heating jacket chamber (38) is defined internally by the drum wall (36) of the reactor drum (18), The burner unit (12) is configured to burn gas to produce heated gas and generate a flow of heated gas that passes through the heating jacket chamber (38). For this purpose, the heating jacket casing (20) is connected via a heated gas supply pipeline (40) so that the heated gas can be introduced into the heating jacket chamber (38). This allows the reactor drum (18) located inside the heating jacket chamber (38) to be indirectly heated from the outside by the heated gas. The rapid cooling unit (16) is connected to the pyrolysis gas outlet (26) of the rotary tube reactor (14) and is configured to cool the pyrolysis gas generated in the reactor chamber (28) during operation. In system (10), Multiple heating gas outlet flaps (44) are distributed along the length of the heating jacket casing (20), and the heating gas outlet flaps (44) can influence the flow of the heating gas through the heating jacket chamber (38) so that different amounts of heat can be supplied to the heating zone (30), the reaction zone (32), and the degassing zone (34) within the reactor chamber (28), respectively. The conveying device (52) is a conveying spiral (52) that extends along a single helical track and is formed by protrusions that project from the drum wall (36) toward the interior of the reactor chamber (28), wherein the helical grooves of the conveying spiral (52) have different pitches in the reaction zone (32) and the degassing zone (34). The pitch of the spiral groove in the reaction zone (32) is smaller than the pitch in the degassing zone (34). The reactor drum (18) has different drum diameters along its longitudinal axis, and the drum diameter is largest in the reaction zone (32). A system (10) for thermal decomposition, characterized by the above.

2. The system for pyrolysis (10) according to claim 1, characterized in that the system includes one burner unit (12) and two rotary tube reactors (14), each equipped with one quenching unit (16).

3. A pyrolysis system (10) according to claim 1 or 2, characterized in that each rotary tube reactor (14) is provided with a rapid cooling unit (16) for condensing and cooling the pyrolysis gas, and the internal pressure in the rotary tube reactor (14) and the rapid cooling unit (16) can be adjusted by an induced fan (94) for drawing out uncondensed pyrolysis gas products.

4. A pyrolysis system (10) according to any one of claims 1 to 3, characterized in that a pyrolysis gas outlet pipe (62) is provided that enters the reactor drum (18) of the rotary tube reactor (14) from the outlet side for removing gaseous decomposition products from the reaction zone (32) and further sending the pyrolysis gas to the rapid cooling unit (16).

5. A pyrolysis system (10) according to claim 4, characterized in that a circular cleaning member (82) having a pipe cross-section is provided for cleaning the pyrolysis gas outlet pipe (62), the cleaning member is connected to a rack (84) and can move back and forth, and the rack (84) is driven via a drive gear (90).

6. The resting positions of the cleaning member (82) and the rack (84) are located within a pipe member (92) facing the pyrolysis gas outlet pipe (62), and the pipe member (92) is formed to be sealed to the surroundings, the pyrolysis system (10) according to claim 5.

7. The system for pyrolysis (10) according to claim 5 or 6, wherein driving energy is transmitted to the rack by an externally located gear motor having a gas-tight shaft feedthrough for the drive gear (90).

8. A pyrolysis system (10) according to any one of claims 1 to 7, characterized in that small lifting blades (54) are regularly arranged between the conveying device (52) of the heating zone (30) and the conveying device (52) of the reaction zone (32) to improve the mixing of the bulk material in the reactor drum (18).

9. A method for producing a pyrolysis solid from waste rubber for further use as a raw material for producing recovered carbon black, using a system according to any one of claims 1 to 8, wherein the system comprises one burner unit (12) and two rotary-tube reactors (14), each having one quenching unit (16), wherein the heated gas produced in the burner unit is mixed with recirculated heated gas and supplied to the heating jacket chamber (38) of the rotary-tube reactors (14) via a heated gas inlet flap (50), wherein the amount of heat and its distribution are supplied to the reactor chamber (28) in a manner that matches the demand by adjusting the heat flow distribution with a heated gas outlet flap (44) located above the heating jacket chamber (38) and its degree of opening, and the heated gases exiting the heating jacket chambers (38) of the two rotary-tube reactors (14) merge in a heated gas recirculation pipeline (46) and are supplied to a heated gas mixing section (48).

10. The method according to claim 9, characterized in that the excess heating gas is guided along the rotary tube reactor (14) via a bypass and supplied to another heat utilization section.

11. The method according to claim 9 or 10, wherein the heated gas generated in the burner unit (12) has a temperature of 850 to 900°C.

12. The method according to any one of claims 9 to 11, wherein the temperature of the heated gas mixture, consisting of the recirculated heated gas and the heated gas from the burner unit, is 580 to 680°C.

13. The method according to any one of claims 9 to 12, wherein the distribution of the heated gas flow within the reactor jacket is adjusted by the degree of opening of three to five heated gas outlet flaps (44) that are uniformly distributed along the longitudinal axis of the reactor drum (18) and positioned above it.

14. The method according to claim 13, wherein the heated gas outlet flap (44) is adjusted to produce a heat distribution in the form of a heated gas volume flow at a rate of 20% for the heating zone (30), 70% for the reaction zone (32), and 10% for the degassing zone (34).

15. The method according to any one of claims 9 to 14, wherein the internal pressure in the rotary tube reactor (14) and the quenching unit (16) is 0.5 to 1.5 mbar higher than the ambient pressure.

16. The method according to claim 15, referencing claim 14, which affects the amount of uncondensed pyrolysis gas by increasing or decreasing the rapid cooling output and consequently increasing or decreasing the pyrolysis gas outlet temperature, in order to compensate for demand fluctuations in the thermal output of the burner unit and thereby avoid the use of a primary energy source such as natural gas or liquefied gas.

17. The method according to claim 14 or 15, wherein the system (10) comprises two induced fans (94) for drawing out uncondensed pyrolysis gas products, the two induced fans (94) supply the synthesis gas / pyrolysis gas to a single common burner system, achieving a supply pressure 20 to 60 mbar higher than the ambient pressure.

Images