SK8601Y1 - Method of thermal depolymerization of plastics material and apparatus for its implementation - Google Patents

Abstract

It is described a method of thermal depolymerization of a plastic material characterized in that the plastic material (4) is fed to the reactor vessel (2) via a feeder (1) in a preheated and compressed state at a temperature of at least 150 °C. In the reactor vessel (2) the plastic material (4) is depolymerized in the absence of air and without catalyst at least partial stirring with a stirrer (6) at a temperature of 200 °C to 500 °C.

Description

The utility model relates to the depolymerization of plastics, in particular mixed plastic materials from municipal and industrial waste, where the depolymerization process takes place continuously with high stability of the process values and the resulting products, in particular the diesel and gasoline fractions. The utility model is also a device for depolymerization of plastic material with continuous filling and removal of material.

BACKGROUND OF THE INVENTION

The processing of plastic material, especially plastic municipal and industrial waste, utilizes depolyroerization and decomposition to produce fission products, especially in the gas phase, which subsequently condense in the distillation columns to the desired diesel and / or gasoline traction. In these processes, it is important to achieve stable depolymerization without interrupting the entire cycle, which typically involves mechanical treatment of the plastic material, drying it, degassing, and subsequent heating in the reactor without access of air.

The solution according to the published patent specification SK 279397 B6 describes a movable bed with a swirling movement of solid particles which are subjected to intense swirling. Stirring the solid particles leads to problems with the mechanical parts of the reactor, and such solutions are only suitable for processing liquid petroleum products or processing mixtures with liquid gases. petroleum products.

The solutions of EP 0591703 A2, EP 0687692 A1, US 20170073584 AJ, WO 03104354 A1, WO 9620254, US 5856599 disclose various complex systems and devices for the depolymerization of plastic material, especially plastic waste. These systems and equipment are complex, require cyclic cleaning of mechanical parts and produce low-quality end products.

The solution according to EP 2599854 A2 uses a group of blades which simultaneously feed the material to be processed. Operation of this equipment requires high energy requirements and. only low quality of the resulting products is achieved.

Published PL 355826 B1 discloses a system with continuous heavy fraction collection in the lower zone of the reactor, but does not explain how to ensure the stability and safety of processes in the system, especially in the reactor.

As has been shown in the operation of the plastic depolymerization apparatus, it is important to achieve thermal stability and thermal homogeneity of the material in the reactor during processing. However, maintaining the optimum temperature throughout the mass of material to be treated in the reactor is problematic in the operating conditions, since the continuous process requires regular addition of plastic material and collection of the heavy fraction without stopping and cooling the reactor. The technological equipment used in this field is usually based on general chemical industry constructions that have not been designed for the treatment of plastic waste, where the material to be treated has a low thermal conductivity and its heating leads to an uneven temperature field. Known devices and processes fail to create a thermally homogeneous environment in a pyrolysis reactor. For this reason, thermochemical processes take place naturally. The resulting products are not homogeneous even at homogeneous inputs, which requires further modification and cost. In order to increase the capacity, the devices have large-volume reactors where a homogeneous environment cannot be achieved.

It is desirable and not known a solution that will substantially stabilize thermal and thus chemical processes and that is reliable and suitable for continuous operation.

The essence of the technical solution

These shortcomings in essence! The method of thermal depolymerization of a plastic material in which the plastic material is first crushed and at least partially dehumidified is subsequently eliminated and subsequently the plastic material is depolymerized in the reactor vessel without air and catalyst without at least partial stirring at 200 ° C to 500 ° C. This technical solution is characterized in that the plastic material is fed into the reactor vessel through a feeder in a preheated and compressed state at a temperature of at least 150 ° C, wherein the material is fed continuously into the vessel during volumetric or mass flow during depolymerization. which is controlled to achieve a constant level and / or a constant mass amount of material in the reactor vessel.

The supply of plastic material to the reactor according to the present invention constitutes the first stage of processing of the plastic material, which is not only a mechanical processing and transfer of the plastic material, but the plastic material is already plasticized and at elevated temperatures of 150-200 ° C. . The compression of the plastic material is accompanied by the expulsion of air or other gases from the strange mass of the plastic material. As a result, the plastic material supplied to the reactor inlet also forms an airtight plug. It is preferred to compress the plastic material at this stage

With K 8601 Υ1, the relative weight of the stranded plastic material corresponding to the bulk density shall be increased up to a value which is equal to the material relative weight of the rigid material with an accuracy of ± 10%. Such compression means that the initially aerated blend of disintegrating plastic material particles is changed at the inlet to the solid mass reactor and / or the solid mass reactor. the material leaking under pressure from the feeder. Compressed plastic material in liquid or semi-liquid form has better thermal conductivity than unprocessed or only crushed plastic material.

The term continuous / continuous throughout this document is to be understood at the point of attachment of the feeder to the reactor vessel and in relation to the time of depolymerization. In short periods of time, of the order of seconds, and at the level of material in the reactor vessel, the plastic material addition process may be trekontinuous, as usually compressed plastic material falls from above the feeder exit, leaving smaller clumps of plastic material from the extruded flow. reactor vessel. Importantly, the feed of plastic material per minute and over a longer period of time is controlled so as to gradually reach a steady state between the incoming plastic material and the outlet components after depolymerization starts, which is accompanied by a stabilization of the level of material in the reactor vessel. Level control can also be achieved by the non-continuous addition of plastic material, for example by adding a single batch of plastic material at varying intervals, but this leads to undesirable temperature fluctuations of the material in the reactor vessel and less stability of the resulting depolymerization products.

The purpose of the first phase in the depolymerization according to the present invention is to compress the crushed and at least partially dehumidified plastic material, wherein the plastic material is simultaneously heated to at least 150 ° C. The plastic material is heated by the compression process itself, which is accompanied by friction and at the same time is heated to a predetermined temperature by added heat, for example from electricity or from the combustion of gaseous fuel. In this treatment outside the reactor vessel, mechanical-thermal low-temperature depolymerization processes are already occurring and at the same time the plastic material is homogenized and dehumidified. The heating of the plastic material already at this stage during its compression results in a better homogeneity of the plastic material at the reactor inlet. At the same time, preheating the plastic material reduces the temperature differences between the material already in the reactor and the plastic material being added. Compressing the plastic material up to the liquid state, resp. The semi-liquid mass improves heat transfer conditions. This process is also referred to herein as the first stage of processing.

In controlling the flow of plastic material to be added, the level of material in the reactor vessel and / or the weight of the reactor vessel may be measured and / or the weight of the material exiting the reactor outputs may be measured. The controlled yet substantially continuous addition of the preheated plastic material has a significant effect on the possibility of achieving high process stability in the reactor. Deposition processes are largely dependent on the temperature at a given location. By achieving the optimum temperature over the entire volume of material in the reactor, conditions are obtained for stable depolymerization with the resulting fractions in the desired range. A constant smooth or stable mass of the material in the reactor must be ensured during the depolymerization process, while at the same time the resulting gaseous products leave the reactor and the heavy fraction is removed from the reactor at intervals or continuously.

The continuous supply of plastic material to the reactor ensures that the proportion of plastic material flowing from the feeder (from the first stage) to the reactor (to the second stage), for example, in one minute of operation accounts for only 3-5% of the total volume of material in the reactor. Such a proportion does not cause significant fluctuations in the temperature in the reactor.

The requirement to achieve a constant level and / or a constant mass amount of material in the reactor vessel is also related to the passage of heat from the heating source to the material to be treated. At a constant level and / or a constant mass amount of material in the reactor, the heat input to the reactor is more easily and precisely controlled. At least partial mechanical mixing of the material in the reactor improves the heat transfer from the outer jacket of the reactor to the mass of the material being processed. Several features of the present invention by their interaction and also by the synergistic effect lead to the formation of a homogeneous temperature field in the mass of material in the reactor. Due to the compression and preheating of the plastic material, the formation of a thin layer of low temperature conductivity polymers in the reactor, where such a layer acts as an insulating layer and causes a temperature gradient increase, is avoided. Due to such a solution, it is sufficient if heat is supplied through the reactor jacket, there is no need for heat exchange elements such as various pipes or piping known in the art to interfere with the interior of the reactor, which subsequently complicates the mixing of the material and cleaning the reactor.

By thermal cracking in the reactor, while ensuring a continuous supply of plastic material without significant temperature fluctuations in the reactor and at reduced pressure, the resulting gaseous constituents rapidly leave the reaction space, thereby limiting the secondary reactions of the gaseous hydrocarbons and hence coke formation.

The present technical solution is operationally reliable and the resulting gasoline and diesel products are of such high quality that they can be used as fuel for internal combustion engines, for example, cogeneration units producing electricity and heat. The technical solution ensures process stability and provides for

S K 8601 Υ1 substitutes for effective control of the composition and quality of output products.

The method according to the present invention comprises measuring the level of the material and / or measuring the weight of the material in the reactor, wherein the addition of the plastic material is controlled according to the level of the material and / or the weight of the material in the reactor. This dependence may have operational inaccuracies that are related to the accuracy of measurement, dosing, and reaction times of each subsystem, such inaccuracies will not be considered as departing from the scope of the present invention.

In order to achieve efficient compression and heating of the plastic material, it is advantageous if the heat to be heated is added in the transport, compression and homogenization phases, whereby the amount of heat in the individual phases can be separately controlled. In the transport phase, the strange plastic material is transferred to the compression zone. In the compression phase the plastic material is compressed and in the homogenization phase the plastic material is already mixed in a semi-liquid or liquid form. All of these phases can be carried out in a single device, for example in a threaded extruder.

In the reactor, the material is depolytnerized based on the thermal action of the external heat added. In the reactor, long polymer chains are broken down into shorter ones, mainly in the form of n-aikans, to a lesser extent isoicans, alkenes, cyclanes and aromatics.

In order to achieve the stated goal of high stability and purity of depolymerization, it is suitable that the unevaporated heavier fractions and solid residues are withdrawn continuously from the reactor. Preferably, this will be carried out at the bottom of the reactor, from where the heavy fraction and the solid residues will be gravitationally discharged into a post-reactor in which the heavy fraction and solid residues are dried at 500-800 ° C. By separating this process into a separate post reactor, contamination of the products in the reactor is avoided. The term post-reactor is a closed vessel that is connected to the reactor outlet, and may also be referred to as a second reactor or dryer. The purpose of the post-reactor is to remove and process material from the reactor which is no longer capable of cracking into gaseous components. Higher temperatures in the post-reactor result in the release of gas and formation of dried solids, which, however, can no longer contaminate the main products discharged from the gas phase reactor. The passage of heavier fractions and solids from the reactor to the post-reactor is controlled by a valve at the bottom of the reactor.

The drawbacks of the prior art are also substantially eliminated by the thermal depolyzerization device of the plastic material itself, which occupies a sealed reactor vessel to which the plastic material infeed feeder is connected, and where the reactor vessel has an outlet for gaseous depolymerization products, has a mechanical stirrer and according to the present invention, the feeder being adapted to compress the plastic material and to feed it continuously into the reactor vessel, the feeder being equipped with heating of the plastic material and the feeder having a flow control of the output plastic material, where the flow control is connected to the control center.

In a preferred embodiment, the feeder is in the form of a threaded extruder with a heated jacket. The outlet of the screw extruder has a continuous character, the flow of plastic material in the head of the extruder is continuous and is easily adjustable by the speed of the screw. Preferably, heating in the feeder is provided at multiple locations, wherein at least one heating location is located in a compression zone where the plastic material is pressed against the walls of the extruder chamber, thereby ensuring good heat transfer to the plastic material mass. In order to ensure sufficient compression of the incoming plastic material and to be mixed at the end of the screw, the screw has a variable cross-section and / or variable thread pitch. The extruder may have a tapered head at the end, at the outlet of which the flow rate of the plastic material in the liquid or the plastic material is increased. semi-liquid state.

In the prior art solutions, screw conveyors are used as material feeders to the reactor. Such feeders are capable of continuously, continuously delivering plastic material to the reactor, but the prior art does not emphasize the continuous supply of controlled flow material according to the level or amount of material in the reactor. The feeder usually operated at the same speed and the hourly flow was controlled by turning the feeder off and on, or the feeder was operating continuously, but the plastic material was loaded into the feeder hopper at intervals. In the solution according to this utility model, the controlled mass flow is continuous and the plastic material is preheated.

The control center of the device is coupled to the material level sensing and / or the mass measurement of the material in the reactor vessel. In operation, the device has a plurality of sensors, control and safety elements. Several of these are known in the art, but continuous control of the amount of material in the reactor is important to achieve the stated technical tasks.

A solution has been found to be suitable in which the reactor comprises a cylindrical double-shell vessel with a conical bottom equipped with an opening communicating with the post-reactor vessel. A heating system is arranged in the space between the inner and outer shell of the vessel. Advantageously, the heating system comprises multi-point gas burners which are located at multiple locations and the combustion gases wash the inner shell of the vessel, thereby transferring heat over a large area. The turbulent flow is thereby prevented

With K 8601 Υί, the reactor jacket is relatively evenly heated. The combustion gases thus rise at least to the height to which the reactor is filled with material and the upper outlet leaving outside the plant, where it can still be used as a secondary heat source. The use of gas burners thi heat generation is also beneficial from. This is because after the start-up of the processes, the actual process gas, which is produced as a by-product of depolymerization, can be used to heat the reactor (as well as the post-reactor).

In order to ensure simple construction and at the same time good temperature conditions of depolymerization, the reactor vessel has a cylindrical shape terminated in a conical constriction where the radius of the cylindrical portion is greater than the height of the material level in the reactor measured from the bottom of the conical portion. The mass of the material in the reactor thereby overcomes the outer boundary, which very coherently corresponds to the spherical die, which is an optimal shape for mixing as well as for uniform heat distribution, and at the same time a relatively large surface area is obtained from which gaseous depolymerization products evaporate. Typically, the level of material in the reactor reaches one to two thirds of the height of the reactor vessel.

The main process of depolymerization in the reactor takes place at least partially with stirring at a temperature of 200 ° C to 500 ° C, preferably at a temperature of 350 ° C to 450 ° C and at a chamber pressure of 15 to 40 mbar. This process is also referred to herein as the second processing step.

When starting the start-up, ie the first start-up or start-up after shutdown, it is advantageous if the reactor is initially filled with oil, which is first heated to the reaction temperature or at least half the reaction temperature before the plastic material from the feeder starts reactor. The plastic material from the compression medium passes to the reactor where the pressure is preferably reduced.

The resulting lighter hydrocarbons are discharged in a continuous mode from the reactor via a cyclone separator to a reflux condenser. In the reflux condenser, some of the hydrocarbons condense on the basis of the selected temperature in the condenser and return to the reactor, allowing further cleavage in the reactor. The residence time in the reactor can be controlled based on the selected temperature of the coolers, thereby optimizing the main process in terms of yield of the desired products. Downstream of the reflux condenser, the hydrocarbon heels proceed to a condensation system where process gas, a light gasoline-water fraction, a wide diesel fraction, and a non-condensable gas fraction are separated. Processes in the second stage of processing are also known from the prior art as partial processes, a substantial benefit of the present invention is to achieve a stable regulatory framework that achieves high purity and quality of the resulting products.

A postreactor that is downstream of the reactor will preferably be located below the reactor so that the unevaporated heavier fractions and the solid residues gravitationally pass into the postreactor without the need for pumping. It is the task of the postreactor to ensure the removal of solid residues as a by-product of depolymerization from the reactor and their sintering and drying, the removal of these residues from the reactor taking place while the depolymerization is still ongoing in the reactor, i.e. without shutdown and cooling. The result is a bulk consistency of coke and mechanical impurities. The post-reactor is connected to the reactor so that material removal is continuous in terms of reactor function. A control element which changes the flow cross-section of the orifice at the reactor outlet is preferably used to control demand.

In order to achieve the desired technical tasks according to the present invention, it is advantageous if the plastic material is continuously added to the reactor and at the same time the unevaporated heavier fractions and solid residues are collected continuously or at intervals while the reactor is active. reactor with a deflection not exceeding 30%, preferably 15%. A good result is already achieved when a plastic material is continually added regardless of the way of removing the unevaporated heavier fractions and solid residues, or good results are obtained if the unevaporated heavy fractions and solid residues are taken continuously or at intervals in the active reactor regardless for a method of adding plastic material to a reactor. Particularly advantageous is the arrangement in which both the addition of plastic material and the removal of unevaporated heavier fractions and solid residues are continuous, both processes being controlled so as to maintain a constant level and / or constant mass amount of material in the reactor vessel.

The post-reactor vessel has its own heating, preferably in the form of a gas burner, which is supplied with process gas from the reactor after starting the process in the reactor. The postreaker may also have its own mixer. The gases exiting the post-reactor are cleaned of impurities by a cyclone and a scrubber. At the bottom of the post-reactor there is a screw conveyor which collects the solid processing residues and discharges through the closure element to the atmospheric environment.

Sensing the stirrer dynamics in the reactor can advantageously be used to control the flow of material between the reactor and the post-reactor. The control center evaluates the stirrer resistance, increasing the resistance means that the stirrer blades move at a given temperature in a material with altered viscosity and / or density. In this state, the mixing is stopped, the mixing direction is changed, opened behind the closing element, at the bottom of the reactor, and the material flows into the post-reactor when the mixing is reversed. The opening and flow time of the material into the postreactor is controlled so as to move a precise amount of material. Subsequently, the return of the bladder is stopped, the reactor outlet is closed and the non-beater is put into proper operation. The mixer in the post-reactor is operated throughout the solids discharge process from the reactor to the post-reactor.

N E 8601 Υ1

If there is no further gasification of the dried material in the post-reactor, which results in a pressure drop, a conveyor, such as a threaded emptying device, is started at the command of the control center. The post-reactor residues are transferred to a sealed solid residue container in the form of a slag. The container is connected to the discharge conveyor neck by a quick coupling. While emptying the postreactor, its mixer is active in reverse. After emptying, the conveyor stops and the mixer starts to run properly. The solid residue container is sealed with a flap and, after opening the quick-release coupling, is transferred to a dedicated space to cool the solid residue.

The process stability and thermal homogeneity are also maintained in the solids drying process in P ostreaklor, where the feedstock processing is finalized. The heavy fractions are discharged into the post-reactor after increasing the resistance of the stirring blades in the reactor, when the closure element is opened and the heavy fractions are discharged into the post-reactor, where they are dried. After a precisely set time, the closure element closes again. Importantly, it does not dump the entire reactor volume, but only its heaviest components dropped at the bottom of the reactor.

The separation part of the apparatus usually consists of three distillation rectification packed columns. The product from the first column is gas oil, which passes through a filtration and cooling system to a storage tank. The product of the second and third columns is a gasoline-water fraction, which passes through a pipeline into a storage tank with sludge equipment. After draining, this light fraction is transported by pipeline to a storage tank equipped with vapor recovery. The condensation system output is still gases that have not condensed at 40 ° C. After the impurities have been removed from the absorber, these gases are discharged via a pipeline to a separate gas management, where they are treated and temporarily stored before use. The yield of beer products ranges from 5 to 30% by weight. %, the gasoline fraction is in the range of 10 to 50 wt. % and the diesel fraction is 20 to 85 wt. %. During the operation of the device it turned out that it can handle even slightly contaminated mixed plastic waste up to 10% by weight without problems.

In order to achieve a compact design of the apparatus with n narrow space requirements, it is suitable if the apparatus is placed in a frame construction having the outer dimensions of the transport container. Advantageously, the frame structure also has the attachment elements of the shipping container and may be transported and lobbyed as a conventional shipping container. Such an arrangement allows the device to be used as a mobile unit which can and will be transported to a landfill site of plastic material.

Achieving high stability and reliable regulatory capability provides the possibility of continuous operation, ensuring a low level of contamination of the output products due to the cleavage of solids. Thanks to good process control and fast regulation possibilities of the equipment, the yield of individual fractions is increased and according to actual requirements the quality and usability of all outputs can be controlled. The stability of the process without severe thermal shocks, especially without cooling, gives a homogeneous product and also reduces the risk of formation of hazardous and toxic compounds.

BRIEF DESCRIPTION OF THE DRAWINGS

The technical solution is explained in more detail with the help of Figures 1 to 8. The illustrated ratio of the sizes of the individual elements of the device is only illusory. The dimensions in the figures cannot be interpreted as restricting the scope of protection.

Figure 1 shows a view of the feeder connection to the reactor. The thick arrows depict the flow of plastic material, its progress from the crusher hopper to the extruder and then to the reactor.

Figure 2 is a view of an extruder having a conveying zone, a compression zone, and a homogenization zone downstream of the plastic material.

Figure 3 shows a view of a double-jacketed reactor where the outlet of the feeder is connected to the reactor from above and the inlet to the post-reactor is connected to the reactor from below.

Figure 4 shows the co-operation of a reactor with a post-reactor having its own mixing and heating.

Figures 5 to 7 show views of the device structure housed in a compact cage with the dimensions of two standardized containers. Figure 5 is a side view, Figure 6 is a front view of the reactor side, and Figure 6 is a top view.

The graph of Figure 8 shows the depolymerization start-up as a function of the material temperature in the reactor. The donkeys show the temperature value in ° C, the y axis shows the time in hours.

EXAMPLES

Example t

In this example of Figures 1, 3 to 8, the device with the necessary elements is placed in a spatial frame structure having the external shape and dimensions of two standard shipping containers.

S K 8601 Stitched on top of each other.

The plastic material 4 is inserted into the hopper of the feeder 1. In this example, the feeder 1 is formed by a screw extruder having a similar construction to the extruder used to inject plastics in the form of granules into molds. the mechanicalnitt of the pressure associated with the thermal interaction relieves moisture The stranded and degassed composite plastic material 4 is advanced in the closed cylinder of the extruder by a specially shaped screw which forms the compression zone 12.

The feeder 1 has a conveying zone 11 from which the plastic material 4 is moved into the compression zone 12, where the plastic material 4 is compressed and passes into the homogenization zone 13 in the compressed state. Each zone 11, 12, 13 is equipped with a heating 14 which transfers heat through the casing of the feeder into the plastic material 4. In the homogenization zone 13, another plastic material 4 of the semi-liquid form, then passes through the conical head of the feeder 1 and through the open ball valve a. with a temperature in the range of 150 ° C to 200 ° C falling from above into the reactor 2.

The plastic material 4 of FIG. 1 enters the hopper of the feeder 1 in the part designated as MF - plastic material inlet 4. Moisture and dust are sucked from the hopper from above by the fan, which then pass through the condenser. Condensation moisture is discharged from the condenser chamber at the bottom. Air resp. the dust gas continues to the dust filter, and the purified air is then discharged into the surroundings via the exhaust head shown in the upper left corner of Figure 1.

At the beginning of the process, the plastic material 4 is crushed, dried and. piastification, with partial cleavage of the polymer chains in feed 1. This phase can therefore be referred to as the first stage of processing of the plastic material 4, the treatment being mechatric-tetmic in nature. In this example, the off-gas from the crusher of the extruder of Figure 1 is connected to an absorber with a vapor condenser, a liquefied gas tank and a particulate filter. This will prevent the spread of dust, dirt, gases and vapors from the shredder to the surroundings.

Reactor 2 has a fixed bed. The plastic material 4 pretreated in the feeder 1, which represents the first stage of processing, comes into contact with the hot mass of material 5 in the reactor at a temperature of 350 ° C to 450 ° C. The level of material 5 in the reactor 2 is in the range of one-third to two-thirds of the internal height of the reactor 2, maintaining a stable level of material 5 after the start of the process.

The reactor 2 has a cylindrical vessel with a conically shaped bottom, having a double-shell construction of the side part and the bottom. Inside the shells there is heating 7 by means of gas burners with three-point heating, which use natural gas as the fuel G for the start-up and after the start of the depolymerization reaction they use their own process gas, which is produced as a by-product of depolymerization. The process in reactor 2, as in the second stage, can be referred to as the main process and takes place at temperatures of 350 to 450 ° C. The flue gas outlet from the heater 7 is represented by an arrow marked EX.

The reactor 2 has a material level sensor 5, in this example an ultrasonic distance meter located at the top of the reactor 2 and directed to the material level 5. The sensor is connected to a control center having a computer with programmed modes and security algorithms . Pressure sensors, temperature sensors and control of individual control elements, motors, heating 7, heating 14 and other safety devices are also connected to the control center. The feed motor 1 has a continuously variable speed to provide the desired flow of plastic material 4. The transitions between feeder 1 and reactor 2, between reactor 2 and postreactor 3 are equipped with a shut-off element which can be separated by process spaces when needed, e.g. processes. Also the outputs of zreaktor 2 and postreactor. are fitted with a closing element.

The reactor 2 is equipped with a mechanical stirrer 6. Depolymerization is carried out at a constant speed of the stirrer 6 and a stable chamber pressure of 15 to 40 mbar. The resulting lighter hydrocarbons are discharged in a continuous mode from the reactor 2 through the production line P and via a cyclone separator to a reflux condenser. In the reflux condenser, some of the hydrocarbons condense on the basis of the selected temperature and return to the reactor 2, allowing further cleavage in the reactor 2. Based on the selected temperature on the condenser, the residence time in the reactor 2 can be controlled to optimize the main process in terms of yield of desired products. Downstream of the reflux condenser, the hydrocarbon vapors are passed to a condensation system where process gas, a light gasoline-water fraction, a wide diesel fraction, and a non-condensable gas fraction are separated.

By thermally cracking in the second stage, while ensuring the continuous inflow of plastic material 4 into the reactor 2, without significant temperature fluctuations in the reactor 2 and at the same reduced pressure, the resulting gaseous constituents rapidly leave the reaction space, thereby limiting the secondary reactions gaseous hydrocarbons and hence the formation of coke. At the same time, there are no large differences in the temperature of the material 5 at the center and at the walls of the reactor 2, which is important for controlling the temperature in the reactor 2 and hence for controlling and controlling the quality and composition of the output products. Depolymerization is stable, does not require a catalyst and is environmentally friendly, does not generate new waste. Cleavage of C-H bonds occurs only by the action of heat in combination with mechanical stress.

At the bottom of the reactor 2 there is an opening followed by an entry into the post-reactor 3, which ensures the continuous removal of solid residues as a by-product of the depolymerization of the reactor 2 and their subsequent fusion,

S K 8601 Υί drying to produce a bulk solid consistency of coke and mechanical impurities.

The highest coke formation and contamination of the liquid fractions occurred in the so-called phase. drying. By separating the drying process into the postreactor 3, i.e. by separating the whole process into three phases, which are carried out continuously, it is ensured that the depolymerization products are not contaminated by impurities - coke as well as solids decomposition products. Importantly, the flow of plastic material 4, material 5 into the individual processing stages is continuous, does not require the reactor to be shut down. The process temperature in the post-reactor 3 is in the range of 500 to 800 ° C. A separate gas burner is used to heat the post-reactor 3. Preferably, gaseous secondary fuel from the plant's own production is used as fuel. The gases exiting from the reactor 3 s and remove impurities from the cyclone and the scrubber.

The postreactor 3 has its own mechanical mixer and has a solids collection conveyor 8 at the bottom, which, after drying in the postreactor 3, represents residues of SL unused during depolymerization. The conveyor 8 has at its end a closing element in the form of a controlled slider valve.

After the device is brought into operation, the temperature 5 of the material 5 in the reactor 2 is rapidly stabilized, after about four hours the temperature stabilizes to an accuracy of ± 10 ° C. The flow rate of the compressed plastic material at the inlet to the reactor 2 in this example is about 7 kg / min.

In this example, the device is used to recycle mixed waste plastics containing mainly polypropylene PP and polyethylene PE in any ratio to each other. In this example, the process results in particular in a liquid fuel for cogeneration units that produce electricity and heat. In the processing of plastic material 4, which for example comes from sorted municipal waste, the process can be controlled so that the yield of gas products is in the range of 5 to 30 mass. %, the gasoline fraction is in the range of 10 to 50 wt. % and the diesel fraction is 20 to 85 mass. %. The products can also be used as feedstock for petrochemical industry operations. The gaseous form of the resulting product includes fuel gas for its own use for the development of the necessary process heat or for other energy purposes.

Example 2

In this example, the feeder 1 of Figure 2 has a variable geometry screw to provide the desired compression ratio. The casing of the feeder 1 has in addition to the electric heating 14 also gas burners, which are supplied with process gas from the storage tank.

The plastic material 4 pretreated in the first stage, i.e. the feeder 1, is not fed to the reactor 2 as the second stage, as in the prior art devices, but is fed, i.e. by a continuous, substantially continuous and controlled rotation of the feeder 1 screw. During the entire process, the plastic material 4 continuously flows into the reactor space 2, in which the traces are still present and the material 5 is heated to the reaction temperature. Thus, in one minute, friction is transferred to the reactor 2 as 5% of the total weight of the material 5 in the reactor 2.

At start-up and after each outage, at least 200 liters of oil are placed in the cold reactor 2, and only after it has been heated to at least half of the reaction temperature, the plastic material 4 from the feeder 1 is transferred to the reactor 2. there are no thermal shocks and the temperature drop in the reactor 2, the melt of the plastic material 4, which is dragged from the first stage to the second stage in the reactor 2, is rapidly heated by contact with the hot reaction mass of the material 5 in the reactor 2 its thin-chemical destruction.

Temperature in our material 5 a. the activity of feeder 1 is shown in the following table:

Time Melt flow of plastic material Material temperature in the reactor .36 7 kg / minute 208  .4 / 7 kg / minute 221 1:58 7 kg / minute 227 2.9 7 kg / minute 23b 2.21 7 kg / minute 242 2.30 7 kg / min 246 2:41 7 kg / minute 262 2:52 7 kg / minute 280 3:00 7 kg / minute 286 3.8 7 kg / minute 296 3.18 0 kg / minute 301) 3:57 7 kg / minute 377 4:43 7 kg / minute 385 5.7 7 kg / minute 386 5.21 7 kg / minute 393 5:36 7 kg / minute 397 5:46 7 kg / minute 394

S K 8601

Time Melt flow of plastic material Material temperature in the reactor 2.6 7 kg / roinut 398 6.24 7 kg / ninety 396 6.29 7 kg / ndout 395 6:39 7 kg / minute 387 6:48 7 kg / minute 395 6:55 7 kg / min 4Q4

The oil in Reactor 2 was heated to 200 ° C. From 1.36 to 3.57, the apparatus was started up at the same time as the melt flow of the plastic material 4, which was heated to a temperature of about 150 ° C. From 3.18 to 3.57, the melt flow of the plastic material 4 was suspended to achieve a faster temperature rise. Then 5, the melt flow of the plastic material 4 was restarted and the apparatus was run in stabilized mode for a further 2 days, the reaction temperature being at a temperature of 400 ° C ± 10 ° C.

Industrial usability

Industrial applicability is obvious. According to this technical solution, it is possible to industrially and repeatedly depolymerize plastics, in particular mixed plastic material from municipal and / or industrial waste, and also to produce and assemble a depolymerization device. In particular, the result is liquid products useful as secondary fuel in cogeneration units or useful for processing in downstream processes in the manufacture of other chemical products.

S K 8601 Υί

List of reference marks and positions

- feeder

-transport zone compression zone homogenization zone

- heating

- reactor

- postreaktor

- plastic material

- material

- not eating

- heating

- conveyor

MF -matéria! teed, plastic material input

EX - exhaust

G - gas, heating gas

P - product, output of products to the separation part

SL - slag, unused solid residues'

Claims (22)

Method for thermally depolymerizing a plastics material, wherein the plastics material (4) is first crushed and at least partially dehumidified and subsequently the plastics material (4) is depolymerized in the reactor vessel (2) without air and catalyst without at least partial stirring at temperature 200 ° C to 500 ° C, in which gaseous depolymerization products are withdrawn from the reactor (2), characterized in that the plastic material (4) is fed into the reactor vessel (2) via a feeder (1) in a preheated and compressed state having a temperature of at least 150 ° C, wherein the plastic material (4) is fed to the vessel continuously during the depolymerization taking place in the reactor vessel (2) at a volume or mass flow rate which is controlled to achieve a constant level and / or constant mass amount of material (5) in the reactor vessel (2). Method for thermally depolymerizing a plastics material according to claim 1, characterized in that the plastics material (4) is plasticized in the feeder (1). Method for thermally depolymerizing a plastics material according to claims 1 or 2, characterized in that the plastics material (4) and the feeder (1) are dehumidified. Method for thermally depolymerizing a plastics material according to any one of claims 1 to 3, characterized in that the plastics material (4) is compressed in the feeder (1) to form a melt flowing from above into the reactor (2). The method of thermally depolymerizing a plastics material according to any one of claims 1 to 4, characterized in that the minute flow rate of the plastics material (4) at the outlet of the feeder (1) does not exceed 5% by volume or 5% by weight of the material (5). 2). A method for thermally depolymerizing a plastics material according to any one of claims 1 to 5, wherein the non-vaporized heavier fractions a. the solid residues from the reactor (2) at its bottom gravitationally pass to the post-reactor (3) during depolymerization in the reactor (2). 7. A process for thermally depolymerizing a plastics material according to claim 6, wherein the non-vaporized heavier fractions and solid residues are removed. at 500 to 800 ° C they dry in the post-reactor (3), where gas is released with stirring and dried solids are formed which are subsequently discharged from the post-reactor Method for thermally depolymerizing a plastics material according to claim 6 or 7, characterized in that the non-vaporised heavier fractions and solid residues from the reactor (2) are transferred to the post-reactor (3) after the agitation resistance of the material (5) increases. ) in the reactor (2). Method for thermally depolymerizing a plastics material according to any one of claims 6 to 8, characterized in that the non-vaporised heavier fractions and solid residues from the reactor (2) are transferred to the post-reactor (3) during the back-mixing of the material ( 5) in the reactor (2). Method for thermally depolymerizing a plastics material according to any one of claims 1 to 9, characterized in that gaseous traction and solid residues are used to heat the plastics material (4) and / or to heat the material (5) and / or to heat heavier traction and solid residues. depolymerization fuel. A process for thermally depolymerizing a plastics material according to any one of claims 1 to 10, characterized in that the depolymerization takes place at a temperature of 350 ° C to 450 ° C and a pressure of 15 to 40 mbar, An apparatus for thermally depolymerizing a plastic material comprising a closed reactor vessel (2) to which a feeder (1) for supplying a plastic material (4) is connected and wherein the reactor vessel (2) has another outlet for gaseous depolymerization products. material (5) and also has an outlet for collecting the non-evaporated heavy fractions, characterized in that the feeder (1) is adapted to compress the plastic material (4) and to feed it continuously into the reactor vessel (2), (1) is provided with heating (14) of the plastic material (4) and the feeder (1) has a flow control of the output plastic material (4) according to the level and / or amount of material (5) in the reactor vessel (2). Device for thermally depolymerizing a plastic material according to claim 12, characterized in that the feeder (1) is in the form of a threaded extruder with a heated jacket and an adjustable screw speed. Apparatus for thermally depolymerizing a plastics material according to claim 13, characterized in that the feeder (1) has a conveying zone (11), a compression zone (12) and a homogenizing zone (13). A device for thermally depolymerizing a plastic material according to any one of claims 12 to 15 14, characterized in that it has a control center which is connected to the material level sensing and / or the mass quantity measurement of the material in the reactor vessel (2) and which is connected to the feeder control (1). A device for thermally depolymerizing a plastic material according to any one of claims 12 to 15 15, characterized in that the reactor (2) comprises a cylindrical double-walled vessel with a cannula bottom, which is provided with an opening connected to the post-reactor vessel (3), between the jacket of the reactor vessel With K 8601 Υ1 (2), the heating (7) is located. Apparatus for thermally depolymerizing a plastics material according to claim 16, characterized in that the heating (7) comprises at least three gas-fuel burners. A device for thermally depolymerizing a plastics material according to any one of claims 12 to 18 17, characterized in that the reactor vessel (2) has another cylindrical shape terminated in a conical taper, wherein the radius of the cylindrical portion is greater than the height of the material level (5) in the reactor (2) measured from the bottom of the conical portion. A device for thermally depolymerizing a plastics material according to any one of claims 12 to 15 18, characterized in that the post-reactor (3) has a mixer, preferably with a variable direction of rotation. A device for thermally depolymerizing a plastics material according to any one of claims 12 to 20 19, characterized in that the post-reactor (3) has a conveyor (8) for discharging dried residues from the post-reactor (3) into a collection vessel. A device for thermally depolymerizing a plastic material according to any one of claims 12 to 21 20, characterized in that it comprises a measuring element for measuring the resistance of the stirrer (6) in the mixing of the material (5) which is connected to the control center. A device for thermally depolymerizing a plastics material according to any one of claims 12 to 21 21, characterized in that it is the same in the frame structure which has the outer dimensions of the transport container or has the outer dimensions of a plurality of connected transport containers.