JP2008531799A - Method for depolymerization of hydrocarbon-containing residues and apparatus for carrying out this method - Google Patents

Abstract

The present invention relates to a process for depolymerizing feedstock containing hydrocarbons such as residues in a continuous process. In order to achieve uniform operation using relatively simple techniques, the raw material preheated to liquid or pulpy consistency is continuously applied under pressure in a reactor (4) heated to the depolymerization temperature. The gaseous fraction is continuously withdrawn from the reactor for further processing, while the bottom fraction is withdrawn continuously or periodically. The raw material is preferably preheated, liquefied and injected by an injection pump or an extruder screw. A high degree of availability is assured in connection with a mixer or doctor head that periodically removes deposits on the inner wall of the reactor.
[Selection] Figure 3

Description

  The present invention relates to a process for the depolymerization of hydrocarbon-containing residues according to the preamble of claim 1, in particular a process for the production of diesel oil and kerosene. The invention also relates to an apparatus for carrying out this method according to the preamble of claim 15.

  For depolymerization of hydrocarbon-containing residues, especially to produce diesel oil, plastic, oil, grease, dry garbage, electrical cables, wood, paper, digested sludge, crop residues, natural fibers, and many Other waste materials or waste or residual materials are depolymerized catalyzed with the goal of obtaining the smallest possible solid and gas conversion products. These processes are performed at peak temperatures between 300 ° C. and 450 ° C. of the material being processed, often in the 400 ° C. region, ie 340-440 ° C. In the presence of an ion exchange catalyst, the depolymerization process, i.e. the molecular shortening of long chain hydrocarbon compounds, takes place relatively quickly due to catalytic cracking. Here, hydrocarbon molecules are deposited on the catalyst until different reaction temperatures are reached depending on the type of residue, and degradable organisms evaporate. In general, fluid / catalyst mixing is performed periodically between the evaporation temperature and the feed temperature. By supplying the raw material, the mixing temperature is lowered. According to the cycle, the desired low-boiling fraction evaporation temperature is reached again with a heater such as a tubular heat exchanger. The component remaining as a liquid is refluxed to the raw material supply unit. The agglomerates formed from the catalyst material and the high-boiling fraction of the raw material in this circulation step are transferred to the outside for further processing. The vapor fraction away from the circulation is refined in a distillation system, producing for example diesel oil or kerosene. The gaseous component is combusted under the production of hot combustion gases, which provides the amount of heat required for evaporation and the liquid cycle processing temperature (pyrolysis temperature). If chlorine, sulfur, phosphorus, and / or other components not desired in the product (diesel oil or kerosene) are included in the feed, these are removed in the circulation process. This is done, for example, through the use of calcium aluminum silicate or sodium aluminum silicate as an ion exchange catalyst and through the addition of, for example, lime for the binding of chlorine, sulfur or phosphorus components to be removed from the feedstock.

In order to carry out this known catalytic depolymerization process, various circulation methods are described, for example, in DE 100 49 377 A1 and DE 103 16 969 A1. In the former case, the finely divided fine raw material is transferred into the first reactor from above through a measuring screw, where the recirculated oil, the catalyst, and the raw material already supplied to the circulation are mixed. The fluid-vapor mixture is fed from the heater to the reactor. A gaseous fraction and a solid-forming fraction are discharged therefrom. The raw material, well mixed with the liquid, is heated here and led to the heater as a fluid mixture via a conduit (DE 100 49 377 A1).
German Patent Publication No. DE100 49 377A1 German Patent Publication No. DE103 16 969A1

  Catalytic depolymerization according to DE 103 16 969 A1 also leads to suspension of the catalyst in the recirculating oil. This is formed by a depolymerization reactor, a hydrocyclone, and a sediment container. Heating is achieved through electrical wall heating in a reactor configured in a unique manner. The reactor has a central feed line for feedstock, fresh catalyst, lime, and recirculated oil, which is directed downwards by a feed screw where it is mixed with circulating fluid refluxing from the sediment container. Within the reactor, the central tube is surrounded by several risers, which allow the mixture appearing in the reactor sump to rise through the feed screw. The riser electrical wall heating ensures that the pyrolysis temperature is achieved and that the liquid-vapor mixture is withdrawn from the top of the reactor.

  Heating the raw material and the fluid containing the raw material to the pyrolysis temperature, unless very carefully heated, will cause local superheating of the liquid mixture and on the reactor wall or reactor baffle, especially on the heat exchanger surface It became clear that the caking of the carbon in the mixture was extremely dangerous because the thermal decomposition of the components of the mixture could not be prevented. Especially in the case of tubular reactors, the tube was blocked, leading to the result of the process stopping. Generally, this precipitate is hard like a rock, so the reactor cannot be used again.

  Starting from this situation, a method having the features of claim 1 and an apparatus having the features of claim 15 are proposed for the depolymerization method according to the classification for improving the supply of raw materials and the supply of heat. . The present invention relates to the basic concept of injecting a preheated raw material having a liquid or slurry-like consistency under pressure into a reactor heated to a pyrolysis temperature.

  According to the present invention, on the one hand, it is possible to produce diesel oil / kerosene from various organic substances in a simple manner and with high yields, on the other hand, by this method of waste and residue recovery, dioxins, By-products such as methane and others can be avoided. Gas production is very low and can be reduced to, for example, about 4.5% of the feedstock. In under-grate firing, this gas can be otherwise reused in the process. The use of a catalyst is possible. However, the method is advantageous because it can avoid the problems and costs of the catalyst and the associated processing.

  In this way, it has been pointed out that the handling of raw materials is greatly simplified and not only the risk of sticking during transfer and in the supply system, but also the risk of caking in the pyrolysis reactor is significantly reduced. Another advantage is that standard components for pressure injection can be used, as is known from plastic injection molding technology.

  In the present invention, a wide variety of hydrocarbon-containing feedstocks (also referred to herein collectively as residues) can be processed into liquid products, particularly diesel oil. Raw materials (residues) are mainly plastics, oils (and waste oils and waste oils), greases, dry wastes, electrical cables, wood, paper, digested sludge, crop residues, natural fibers, and many other old materials or waste Or it can be old materials such as residual materials, recycled materials and wastes, as well as renewable materials and rubbers. The treatment of plastics and waste oils is particularly advantageous. Thus, pyrolysis or depolymerization processes can be used to produce high quality commercial products, ie kerosene or diesel oil.

  It is particularly preferred to preheat the mixture produced from plastic and waste oil, and it is particularly preferred that this preheating is carried out to a temperature above 200 ° C., in particular to a temperature between about 250 ° C. and 300 ° C. The essential advantage here is that the water in the charge mixture evaporates and is not introduced into the reactor. In addition, all other low-boiling substances are also discharged, and thus do not need to be transported outside by the system. The waste heat of the pyrolysis reactor can be used for this purpose.

  The plastic to be introduced is preheated, for example through heat transfer heating, regenerative heating, or frictional heating, and supplied, for example, to the injection nozzle of the extruder, from where it is injected into the reactor under a fixed or set pressure. This process can be carried out continuously through a suitable selection of injection nozzles that can also be formed by the pressure generated and / or the opening of the line. That is, the raw material is continuously and substantially uniformly supplied into the reaction apparatus. In order to maintain a constant charge in the reactor, it is of course necessary to remove gases and solid and liquid components and to adapt the feeds to match each other. This leads to a constant processing state and guarantees a constant product quality. Waste oil can be introduced into the reactor in a similar manner. The raw material is further heated in the reactor, where the long chain hydrocarbons are broken down into short chain molecules. At this temperature, these molecules leave the bath as a gas and rise in the distillation column. Depending on their length, molecules are captured at different stages of the tower. If the processing parameters of the tower are set appropriately in a known manner, a product, ie diesel oil or kerosene, is obtained in the accumulator, for example by water cooling. Until now, the charge was supplied to the reactor in finely divided state without any special measures.

  The injection is performed in the central region of the reactor for careful additional heating.

  For further optimization of the heating of the feed, it is proposed to form the reactor in particular as a rotationally symmetric pot with a parabolic or hyperbolic internal profile in which the multiblade mixer rotates. It is advantageous if the end of the mixing arm is made from a refractory ceramic or graphite material and / or the internal contour of the reactor is essentially doubled with very little play, in order to prevent or eliminate deposition . In this way, the decomposed carbon accumulates on the bitumen slurry formed as waste and is disposed of with this slurry instead of caking on the reactor heating wall.

  When using a pot reactor with a stirrer arm, heat transfer is stronger and turbulence occurs in the liquid, which lowers the top surface temperature and leads to reduced free carbon formation. Stirring or scraping near the surface also prevents deposition and overheating and simultaneously improves heat transfer through the reactor wall.

  Surface cleaning of the reactor inner wall is also of independent significance and preferably with minimal or no lateral play by a periodic scraping device that is periodically guided along the contour of the reactor inner wall. And can optionally be performed without the target mixing effect. The contour of the inner wall of the rotationally symmetric reactor is preferred for this purpose. In this case, the scraping head of the scraping device carries at least two contour-matching scraping elements that are driven to rotate. They can be provided with replaceable closure backings, where excess wear play can be detected, for example through electrical measurements. When the scraping head comes into contact with or is pressed against the inner wall of the reactor by its own weight or due to the effect of the force applied through its rotating shaft, even a small coagulum is removed from the inner wall of the reactor and transferred to the outside, for example Can be sent to the reactor sump to do so.

  Such scraping devices are subject to the risk of caking in some situations and can limit the effectiveness of the device. For this purpose, the scraping device can be protected by a self-cleaning element which can be activated at any time, in particular for the cleaning of the scraping element by the scraping head. A typical cleaning cycle for a rotary scraper with two blades is about 1 to 1000 cleaning cycles per hour, preferably the rotational speed of the scraping head is 1 to 20 rotations per minute, preferably 5 to 10 It is a rotation. Depending on the size of the reactor and the caking sensitivity of the raw material to be depolymerized, the weight of the scraping device producing a specific contact pressure can be from several grams to several thousand kilograms. For reactors with a capacity of about 1 cubic meter, the typical weight of the scraping head is on the order of 10 to 1000 kg, preferably between 50 kg and 200 kg.

  Under the influence of such a scraping device, which preferably also has a mixing effect, the temperature difference between the average desired temperature of the liquid to be depolymerized in the reactor and the outer wall of the reactor can be advantageously kept low. For example, it can be maintained at about 20 to 80 ° C.

  Another aspect of the present invention is the improvement of a scraping device for depolymerization reactors and the like. In this aspect, a self-cleaning element of the scraping head for occasional cleaning of the scraping element during a continuous depolymerization operation is proposed. As one practical realization, the self-cleaning element can move relative to the scraping device in mutual contact with the scraping element. Such movement can be performed perpendicularly to and along the scraping blade. Actuation is preferably performed by means of a rotating shaft, in particular through telescopic movement. The self-cleaning scraping element alone has an inventive significance.

  Another aspect of the invention is the structure of the reactor that supports the continuous availability of the depolymerization system. In this regard, the reactor can be separated from the reactor cover with the distillation column by lowering it with its heater and replaced with a new or dismantled reactor. If the reactor is dish-shaped and can be loaded into a heating jacket, the reactor can be quickly replaced, for example for demolition inspection. The diverting element on its outer surface allows for effective heat guidance for heating, maintaining temperature and also for cooling. This aspect of the invention also has inventive significance alone.

  The components used in accordance with the present invention as specified above and in the claims and embodiments are subject to any special exceptional conditions with respect to their size, shape, material selection, or technical concept. Can be used without limitation, selection criteria known in the field of application.

  Additional details, features and advantages of the subject matter of the present invention will become apparent from the dependent claims and from the following description of the accompanying drawings and tables which show embodiments of catalytic depolymerization as an example. I will.

  The block circuit diagram of FIG. 1 shows that a raw material 1 consisting of plastic and waste oil is heated to 250 ° C. in a preheating stage 2 and then a pressure injection apparatus such as a pressure and feed pump known in plastic injection molding. (Injection 3). This pump allows the raw material to be injected directly into the pyrolysis reactor (reactor 4), whose liquid component is about 300 by the heater 5 (eg, oil or gas at about 800 ° C. and waste gas). The pyrolysis temperature is maintained between 0 ° C. and 460 ° C., preferably between 340 ° C. and 440 ° C., in particular between 390 ° C. and 420 ° C., and the waste heat is partly in the preheating stage 2, for example a heat transfer heater. Collected. A gaseous fraction is withdrawn from the reactor 4 and after a corresponding treatment such as rectification, it is obtained as product 8. Similar to known methods, the solids produced in the reactor are removed from the reactor 4 and released from the oil, obtained as a residue 7 and optionally further processed.

  It will be appreciated that the reactor 4 can be constructed in various ways. Similarly, there is no narrow constraint on the heater 5.

  FIG. 2 presents a basic representation of the possible structure of the depolymerization system according to the invention. The preheating of the raw material 1 is performed through external heating and / or friction with feed and compression screws. Here, various raw materials such as plastics, oils, in particular waste oil / drainage, and optionally additives are supplied at various points. At least after partial preheating, the pressure drops. In the expansion stage 2A, water vapor and other gases can be sent to the filter, for example via an exhaust line. Pots that are transported by the outer end of the supply screw and heated externally, with the raw material that is almost or almost completely liquid or slurry in the middle, optionally with additional heating and increased internal pressure It is injected into the shape depolymerization reactor 4. The reactor cover 4D carries a distillation column 9 which is connected on the outside to a head condenser and, for example, a kerosene / diesel product tank. The sump product is transferred to the outside for further processing / reuse at 4B. Gaseous pyrolytic organisms are guided after exit from the depolymerization reactor, preferably through a high speed cyclone with a large safety vessel. This uses a so-called demister to remove the vapor of particles carried by the aerosol. From there, the desired pyrolytic organism is introduced into the distillation column. It is preferable to measure the filling state of the reactor 4 and adjust it to a desired value. This is executed by a known measurement probe with the gas space 4A left open (see FIG. 3).

  Through the mixing / scraping head shown in FIG. 3, the reactor inner wall 4C is continuously cleaned, where the solid components are sent down to the reactor sump, preferably moving spirally. The filling state of the solid component of the reactor sump is preferably monitored using a non-contact method. The reservoir 4B holding the sump product allows for the collection of solid components in the steady flow zone.

  FIG. 3 shows a principle view (center longitudinal section) of a rotationally symmetric reactor 4, for example in the form of a pot, with several stirring arms 8A and blade-like mixing elements 8B which can be made at least partly from ceramic or graphite material. Figure). The mixing element 8B is adapted to the dome-shaped inner contour, ie the inner wall 4C of the reactor 4, and can maintain a relatively small gap S there. Accordingly, caking deposits are constantly removed from the internal contour of the reactor 4 which is preferably heated from the outside. In addition, overheating of the contents proximate the reactor wall is prevented by thorough mixing of the reaction contents. In this embodiment, the reactor outer wall 4 </ b> E forms a part of the air box of the heater 5. For this purpose, the reactor pot 4G is provided with a peripheral opening flange 4G 'on the flange 5A' of the box-shaped superheat jacket 5A. In the heating jacket 5A, there is an intermediate platform 5B having perforations, and a high-temperature gas of, for example, 560 ° C. is supplied from the mixer 5D through the flexible line 5C. This occurs, for example, by mixing room temperature (RT) air with the gas-fired flame exhaust, which is applied by the fan 5E. The high temperature exhaust exits the heating jacket via the outlet 5F. The reactor 4 is sealed by a reactor cover 4D that contacts the open flange 4G '. This cover carries the distillation column 9 and holds the raw material supply path 4H. It is held stationary on the appropriate frame. For purposes such as cleaning, the reactor pot 4G, along with the heating jacket 5A, can be detached from the reactor cover 4D and lowered as shown by the double-headed arrow, then through, for example, turning (double-headed arrow R), It can be taken out from the position under the reaction vessel cover 4D. In this way, the stirrer or scraping head not yet described can be removed simultaneously (FIG. 4). The outlet for the residue is correspondingly flexible or detachably connected to the residue line. In this embodiment, the outlet consists of a reactor sump 4B provided with a heat insulating wall 4B ′ guided outwards via a heating jacket or wind box, which is intermittently closed by a discharge air lock 4J. Can do.

  As can be seen from FIG. 4, the rotary shaft 4E of the scraping or mixing head shown in FIGS. 7 and 8 is such that the drive motor M remains fixed to the drive shaft on the reactor cover 4D, while the head is free from vertical play. Can be disconnected by a pluggable rotary drive connection.

  7A / 7B show a first embodiment of a scraping head 10D that can be used as a stirrer in the embodiment according to FIG. In these figures, the two side views are designated a) and c), respectively, and the top view is designated b). Two substantially quadrant blades 10B can be seen from FIG. 7Ba), which together form a substantially semicircular shape, with the radially outer side acting or formed as a scraping element 10C. The scraping element 10 </ b> C can contact the inner wall 4 </ b> C of the reaction device 4 due to the weight of the scraping head 10 </ b> D. During the depolymerization process, the scraping head 10D, which also serves as a mixer, rotates slowly, for example at a speed of 5 to 10 revolutions per minute. In this way, deposits continue to be removed from the reactor walls. After a specific period of operation that can be determined through experience or measurement, the scraping head 10D is cleaned by the self-cleaning element 10G in a continuous rotational state or during interruption of the rotational movement. This is repeated in the sickle-shaped blade 10B embodiment and is positioned during normal scraping operations at a distance from the reactor wall as shown in FIG. 7B. The self-cleaning element 10G is connected to a drive element 10H guided in a telescopic manner within or on the rotating shaft 10E. The self-cleaning element 10D is displaced in the vertical direction through the expansion and contraction of the driving element 10H. Here, the scraping blade 10G ′ comes into contact with the blade 10B and removes the caking deposit from the front blade surface so as to scrape in the rotational direction until it approaches or comes into contact with the scraping blade of the scraping element 10C. To do. This scraping self-cleaning step can also be performed through multiple back and forth reciprocating motions. Alternatively, self-cleaning is achieved by relative movement between the self-cleaning element and the scraping element so that the self-cleaning element remains in its original position and the scraping element is raised by an appropriate amount and then lowered again. It is also possible to execute.

  In the embodiment shown in FIGS. 8A to 8C, the scraping element 10C has a C-shaped cross section and is connected to the bottom end of the rotating shaft 10E, and each of the profiles holds the driving element 10H in the guide path. Prepare. The self-cleaning head 10G "can also be guided along the scraping element 10C and is arranged in mutual contact on this element. This self-cleaning head is connected to one end of the associated drive element 10A and is therefore driven 10H moves along the scraping blade as it moves to expand and contract with respect to the rotating shaft 10E, showing the various intermediate positions of the self-cleaning head, which in the illustrated embodiment is approximately U The U-shaped leg does not protrude outward beyond the scraping blade of the scraping element 10 C. The possible usage is consistent with the embodiment according to FIGS.

  Incidentally, the scraping element can be formed in various ways. In the embodiment of FIG. 5, the scraping element 10 </ b> C is composed of a material profile that is held by a cage 10 </ b> F having a separation layer 12 </ b> A at an intermediate position. The material is selected according to the desired wear resistance or reactor wall protection. In this embodiment, wear has already progressed so much that the retainer 10F is almost in contact with the reactor wall. As wear progresses until such contact occurs, the cage 10F and scraping element 10C are conductively bridged by the reactor wall 4C. The evaluation circuit then determines the allowable limit wear and reports that the scraping element 10C should be replaced.

  FIG. 6 shows that the reactor pot 4G is provided with a flow guide element 4F on its outer wall 4E that facilitates efficient heating or cooling. In particular, a circulating flow of warm air can be achieved. The heating jacket 5A of the heater 5 can be shaped accordingly for further promotion of this purpose. Similarly, the diversion element can be adapted to the internal contour of the heating jacket 5A. A fixed connection of the diversion element to the outer wall of the reactor allows the reactor pot to be easily disconnected from the heating jacket, thus enabling a particularly quick exchange of the reactor pot.

The block circuit diagram of a depolymerization system. Overview of practical setup of depolymerization system. The schematic longitudinal cross-sectional view as a principle figure cut along the center of the reactor of the depolymerization system containing a reactor heater. FIG. 4 is a detailed view of the coupling between the rotating shaft and the scraping head of the reaction apparatus according to FIG. 3. FIG. 5 is a cross-sectional view of the same reactor of FIG. 3 (cross-section along line VV) showing the scraping element held and moved by the holder. The perspective view of the outer side of the reactor of FIG. Scraping head for scraping position for depolymerization reactor. Same scraping head in self-cleaning position. An alternative embodiment of a scraping head in a scraping position. The expanded sectional view of the same scraping head in the position under self-cleaning of a scraping head. FIG. 9 is another enlarged detail view of the same scraping head (in the position according to FIG. 8B).

Explanation of symbols

1 Raw material 2 Preheating stage 2A Expansion stage 3 Injection 4 Reactor 4A Gas space 4B Sump 4B 'Wall 4C Inner wall 4D Reactor cover 4E Outer wall 4F Conducting element 4G Reactor pot 4G' Opening flange 5 Heater 5A Heating jacket 6 Product 7 Residue 8 Stirrer 8A Arm 8B Mixing element 9 Distillation tower 10 Scraping device 10A Arm 10B Blade 10C Scraping element 10D Scraping head 10E Rotating shaft 10F Receptor 10G Self-cleaning element 10G ′ Scraping blade 10G ”Self-cleaning head 10H Drive element 12 Wear detection device 12A Separation layer

Claims (41)

  A process for depolymerizing a hydrocarbon-containing feedstock, such as a residue, in a continuous operation process, wherein the feedstock in liquid or slurry form is preheated continuously under pressure, at a pyrolysis temperature. The gas fraction is continuously injected out of the reactor for further processing, and the sump fraction is also continuously or periodically transferred out of the reactor. A method characterized by being made.   The method according to claim 1, characterized in that the injection is carried out under pressure using an injection pump or an extruder screw similar to those known in particular for plastic injection molding.   3. Process according to claim 1 or 2, characterized in that the raw material in an infusion pump or extruder screw is exposed to a pressure between 100 and 1 bar, preferably between 100 and 2 bar.   A method according to one of claims 1 to 3, characterized in that the preheating is carried out to a temperature above about 100 ° C, preferably above about 250 ° C.   The preheating is performed in two stages. In the first stage, the raw material reaches a temperature of about 100 to 150 ° C. in a kneaded and compressed state for the removal of gas and interstitial spaces. The process according to one of claims 1 to 4, characterized in that preheating up to ~ 300 ° C is carried out.   6. A method according to claim 5, characterized in that a pressurized expansion stage for separating a gas such as water vapor is first carried out in connection with the first preheating stage.   The method according to one of claims 1 to 6, characterized in that the raw material comprises at least one plastic.   8. A method according to one of claims 1 to 7, characterized in that the raw material comprises at least one oil.   A process according to one of claims 1 to 5, characterized in that the heated wall zone of the reactor is cooled through stirring of the reactor contents close to the wall.   The reactor temperature of the inner wall is maintained during depolymerization at a temperature between 300 ° C. and 460 ° C., preferably between 340 ° C. and 440 ° C., particularly preferably between 390 ° C. and 420 ° C. 10. A method according to one of claims 1 to 9.   11. Process according to one of the preceding claims, characterized in that the raw material is supplied to the fluid to be depolymerized at a distance from the reactor wall, in particular in the central region of the reactor.   The heated wall zone of the reactor is characterized in that, during depolymerization, caking deposits are periodically removed across their surfaces using a scraper shaped to fit the wall profile. 12. A method according to one of claims 1 to 11.   The method according to claim 12, wherein the scraper is self-cleaning from time to time.   By separating the reactor from its cover and / or further processing steps, for example from a distillation column, lowering it and moving it sideways if necessary or swirling it, 14. A process according to one of claims 1 to 13, characterized in that the reactor is exchanged.   An apparatus for depolymerizing hydrocarbon-containing raw materials such as residues in a continuous operation process according to one of claims 1 to 13, particularly a heated pyrolysis reactor (4), a liquid, a paste (2) for pre-heating a solid and / or solid hydrocarbon-containing raw material, and an apparatus for supplying the raw material (1) having a liquid or slurry-like consistency into the reactor (4) (3), a distillation column (9) fluidly connected to the gas space (4A) of the reactor (4), a reactor sump (4B) for transferring sump material to the outside, and during the depolymerization process And a scraping device (10) for periodically cleaning the inner wall (4C) of the reactor coated with at least a liquid.   In order to inject the preheated raw material into the pyrolysis reaction device under pressure, a preheated raw material (1) connected as a feeding device (3) to the input portion of the pyrolysis reaction device (4) The device according to claim 15, characterized in that it is a pressure injection device such as an injection pump or an extruder screw for use in the above.   19. A device according to claim 15 or 18, characterized by a pot reactor (4).   18. Apparatus according to claim 17, characterized in that the reactor (4) has a rotationally symmetric internal contour.   19. The device according to claim 18, characterized in that the reactor (4) has a substantially crown-like internal contour.   Device according to one of claims 15 to 19, characterized by a multi-blade with arms (8A) and blades (8B), a rotatable / rotatable mixer, or a stirrer (8).   21. Device according to claim 20, characterized in that the blade (8B) is at least partly composed of a refractory ceramic or graphite material.   Device according to claim 19 or 20, characterized in that the blade (8B) essentially replicates the contour of the inner wall of the reactor (4).   Device according to one of claims 15 to 22, characterized in that the scraping element (10C) of the scraping device (10) essentially duplicates the contour of the inner wall of the reactor (4).   The scraping device (10) has a scraping head (10D) composed of a rotating shaft (10E) and at least two blades (10B) having a scraping element (10C), 24. The device of claim 23.   25. The scraping head 10D contacts the inner wall (4C) of the reactor (4) by its own weight and / or by pressure maintained by the rotating shaft (10E), according to claim 24, The device described.   The rotary shaft (10E) has in particular a pluggable rotary drive connection, which allows movement of the scraping head (10D) and wear of the scraping element (10C) so that the wear play is even. 26. The device according to claim 25, characterized in that increases.   27. One of the claims 23 to 26, characterized in that the blade (10B) of the scraping head (10D) has a retainer for a scraping element (10C) formed as a wear part. Equipment.   28. Device according to claim 27, characterized by a separation layer (12A) for preventing contact between the retainer (10F) and the scraping element (10C) on the blade (10B).   29. Device according to one of claims 23 to 28, characterized by a wear detection device (12) for the scraping element (10C).   An electrical circuit for detecting a conductive bridge between the scraping element (10C) and a holder or attachment of the scraping element (10C) as a signal of a state of advanced wear of the scraping element 10C 30. The apparatus of claim 29.   31. The self-cleaning element (10G) of the scraping head (10D) for cleaning the scraping element (10C) from time to time, especially during continuous depolymerization operations. apparatus.   32. Device according to claim 31, characterized in that the self-cleaning element (10G) moves relative to the scraping element (10C) in mutual contact with the scraping element (10C).   The self-cleaning element (10G) can be displaced along the scraping element by a drive element guided on or in the rotary shaft (10E). apparatus.   34. Device according to claim 32 or 33, characterized by the contour of the scraping blade (10G ') of the self-cleaning element (10G) essentially matching the contour of the scraping element (10C).   35. Device according to one of the claims 31 to 34, characterized in that the self-cleaning element (10G) is arranged on the front side of the scraping element 10C in the direction of movement.   34. Device according to one of the claims 31 to 33, characterized in that it comprises a self-cleaning head 10 "which can be moved along the scraping blade of the scraping element 10C.   37. A device according to claim 36, characterized in that the self-cleaning head can be moved along the scraping element (10C) by means of an elastic drive element (10H) guided along the scraping element (10C). The device described.   The reactor (4) is preferably separated from the reactor cover (4D) along with its heater (5) and can be separated from the distillation column (9) by lowering and fresh or demolition inspected. 38. Device according to one of claims 15 to 37, characterized in that it can be exchanged for a reactor.   39. Apparatus according to one of claims 15 to 38, in particular 38, characterized in that the reactor (4) can be installed deeply in a heating jacket (5A).   In order to enhance the thermal contact between the reactor (4) and the fluid that cools or heats the reactor outer wall (4E), the reactor has a diversion element on its outer wall, 40. Apparatus according to one of claims 15 to 39, in particular 38 or 39.   41. The device according to claim 40, characterized in that the flow-guiding element generates a circulating fluid flow on at least a partial peripheral surface of the reactor (4).

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