Char treatment section and depolymerization process associated therewith

Abstract

A carbon treatment section is provided for handling carbon containing a liquid slurry, comprising a series of devices for the progressive depolymerization of the liquid slurry and the drying of the carbon, which is then collected and disposed of. This configuration of the process and apparatus for carbon removal treatment and disposal is highly flexible and allows for continuous operation without stopping the depolymerization reactor.

Description

Technical Field

[0001] This invention relates to the field of depolymerizing waste plastic materials into novel products including hydrocarbon oils, which possess valuable and useful properties. In one aspect, this invention relates to processes and equipment for treating the carbon produced by the said depolymerization process. Background Technology

[0002] The awareness that waste plastics have a negative impact on the environment and therefore on the health of all forms of life is rapidly increasing.

[0003] One attempt to mitigate this impact is to recycle plastic materials from household and industrial waste, allowing a portion of these materials to re-enter the production cycle. This would lead to further positive outcomes, such as using fewer fossil hydrocarbon sources to produce plastic products.

[0004] However, various factors indicate that this solution alone is insufficient to achieve sustainability goals. In fact, the mechanical recycling of plastic materials typically produces lower-quality materials, is relatively costly, cumbersome, and unsuitable for municipal waste containing certain plastics mixed with various other materials.

[0005] Therefore, most plastic waste is either used as thermal energy in equipment such as incinerators or simply stored in landfills, which, as mentioned above, contribute to the degradation of the Earth's environment by increasing CO2 emissions and releasing harmful chemicals.

[0006] In view of the above, many attempts have been made in the past to effectively reprocess waste plastic raw materials into liquid hydrocarbon products, which have valuable and useful properties, especially as fuel.

[0007] Thermocatalysis is a fundamental process by which plastic waste is converted into liquid fuels (pyrolysis products) through thermal and selective catalytic degradation in the absence of oxygen. Plastic waste is typically first melted in a stainless steel chamber under an inert purging gas such as nitrogen. In the first thermal step, the chamber heats the molten material to a gaseous state, where it is subsequently cracked in a thermocatalytic step to form hydrocarbon chains of varying lengths.

[0008] The hot pyrolysis gases are then condensed in one or more condensers to produce a hydrocarbon distillate (pyrolysis oil) comprising straight-chain and branched aliphatic, cyclic aliphatic, and aromatic hydrocarbons. Depending on the composition, the resulting mixture is used in a variety of applications, but in all cases, product consistency and quality requirements must always be met. Due to the unstable composition of waste plastic raw materials, achieving consistent quality in the recycled oil is difficult.

[0009] Despite the use of catalysts and harsh conditions, the depolymerization reaction produces a large amount of sticky carbonaceous material, partially in carbon form, as a byproduct. This also includes inorganic materials derived from plastics or additives contained in the depolymerization catalyst. Due to its stickiness, the carbon adheres to the reactor walls and reduces the heat transfer coefficient, thereby also reducing process productivity and efficiency. Therefore, the produced carbon must be removed to maintain process operability.

[0010] Industrial pyrolysis or thermocatalytic equipment can have two pyrolysis chambers, called a dual-chamber system, which operate in parallel at approximately equal rates. While both chambers are completing the pyrolysis of the waste material concurrently, each chamber must be allowed to cool before the carbon is removed from its internal substrate. In a variation, the chambers can operate in an alternating mode, such that one is in the cleaning process while the other is in operation. However, this method reduces the amount of plastic processed per unit time.

[0011] To avoid the cleaning steps of the depolymerization chamber, one technical solution is to drain the contents of the depolymerization chamber while it is still in slurry form rather than a solid, viscous substance. Slurry form, especially if the carbon content in the slurry is not highly concentrated, allows the carbon to not adhere to or adhere to the reactor walls to a limited extent.

[0012] However, the relatively diluted slurry extracted from the reactor has a high content of hydrocarbon chains, which still needs to be depolymerized in order to produce pyrolysis products at a suitable and acceptable productivity.

[0013] Therefore, the carbon treatment section needs to be configured to handle the large volume of effluent from which carbon is extracted and to complete the depolymerization reactor.

[0014] In view of the above, the object of the present invention relates to a carbon processing section capable of receiving and processing a liquid effluent containing carbon in the form of a slurry. Summary of the Invention

[0015] Therefore, one aspect of the present invention discloses a carbon treatment section, comprising:

[0016] The first jacketed chamber (6a) is provided with an inlet conduit (6a-1) for feeding carbonaceous slurry and a stirring system (6b) capable of operating in a temperature range of 350-570°C, and further provided with a conduit (6b-1) for discharging gaseous effluent, and

[0017] The device (6c) is used to discharge concentrated slurry from chamber (6a) and convey it to a second chamber (6d). The device (6c) is capable of maintaining the slurry within the same temperature range as chamber (6a) and is provided with a degassing system for removing gaseous effluent and generating discharged carbon.

[0018] The second stripping chamber (6d) receives the discharged charcoal and is equipped with a stirring system (6d-1), a charcoal outlet (6d-2), a gas inlet (6d-3) located at the bottom of the chamber, and a gas outlet (6d-4) for removing gaseous effluents stripped from the charcoal.

[0019] The device (6e) is used to receive the dry charcoal from the stripping chamber (6d) and transport it to the third collection chamber (6f), and the device (6e) is capable of maintaining the charcoal in a temperature range of 60-100°C.

[0020] The third collection chamber (6f) receives dry charcoal and is equipped with a stirring system (6f-1) and an outlet for charcoal disposal operated by a valve (6f-2). Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the thermocatalytic process equipment.

[0022] Figure 2 This is a schematic diagram of the carbon treatment section. Detailed Implementation

[0023] As described above, the carbon treatment section of the present invention has the purpose of separating and disposing of the solid portion of the slurry as an effluent from the depolymerization reactor. Figure 2 A schematic diagram of the process is shown.

[0024] In a preferred embodiment, the hot slurry discharged from the depolymerization reactor is sent to a jacketed chamber (6a) operating in a temperature range of 350-570°C, where the depolymerization process can be carried out under stirring provided by rotating blades (6b) through the heat transferred by the thermal jacket. The resulting gaseous effluent leaves the chamber (6a) and is preferably sent to a condensation unit (3) and treated together with the gaseous effluent from the first reactor (2). Preferably, a filter is installed on the gas outlet duct to block entrained carbon particles. In a specific embodiment, the gaseous effluent is first condensed in a dedicated unit and then pumped back to the condensation unit (3).

[0025] A concentrated slurry (mud) is formed and discharged from the bottom of chamber (6a) by a screw (heat) conveyor (6c), which then transfers it to chamber (6d). The screw conveyor (6c) is preferably jacketed so that it can operate within the same temperature range of chamber (6a). In a more preferred embodiment, molten, sun-dried salt circulates within the jacket of chamber (6a) and the screw conveyor (6c).

[0026] The screw conveyor (6c) preferably consists of two different conveying mechanisms connected to each other. Preferably, a concentrated slurry, preferably in the form of mud, is discharged from the bottom chamber (6a) by a first lifting screw conveyor (6c-1), the lower end of which is integral with the bottom of the chamber (6a), and its upper end positioned at a higher height relative to the lower end. The first lifting screw conveyor (6c-1) is connected to one end of a second screw conveyor (6c-2), the other end of which is connected to and feeds into the upper part of the stripping chamber (6d). Both conveyors are jacketed and operate within the same temperature range of chamber 6a.

[0027] As the mud rises from the bottom of chamber (6a) and is conveyed to stripping chamber (6d) via a second conveyor, it is gradually discharged as the liquid portion flows back into chamber (6a) and is partially converted into the removed gaseous effluent.

[0028] The above system allows the feeding of carbon material containing a limited amount of liquid and preferably partially dried into the stripping chamber (6d).

[0029] In the stripping chamber (6d), nitrogen is preferably injected into the bottom of the stripping chamber to remove volatile hydrocarbon products. Gas is discharged from the top of the stripping chamber (6d) and sent to the condensation unit (3), while dry char is discharged from the bottom of the chamber, preferably via a ball valve, into another jacketed screw conveyor (6e) maintained at a temperature range of 60-100°C, which directly conveys the char to a stirred collection chamber (6f), preferably operating at approximately atmospheric pressure and a temperature range of 60-100°C. More preferably, nitrogen is circulated in the collection chamber through a gas inlet (6f-3) and a gas outlet (6f-4). Finally, the dry char is preferably discharged through a valve (6f-2) into a mobile container (6g) for further disposal.

[0030] The disclosed processes and equipment for carbon removal treatment and disposal are highly flexible and allow for continuous operation without stopping the depolymerization reactor. This also allows for lighter depolymerization equipment, as it is no longer strictly required to have reactors operating in parallel for a continuously operating depolymerization process. Preferably, the carbon treatment section is fed a slurry with a carbon content of 10-50 wt%, preferably 20-40 wt%.

[0031] In particular, the entire carbon generation, removal, and treatment system is continuous, scalable, flexible, and has little impact on the overall operability of the depolymerization process.

[0032] The carbon treatment process is also very effective in releasing dry char with a typical composition of approximately 20 wt% spent catalyst, 50 wt% inorganic matter, and approximately 30 wt% carbon.

[0033] The carbon treatment section can be associated with any depolymerization equipment operating the depolymerization reactor, from which the carbon-containing liquid slurry can be discharged.

[0034] refer to Figure 1 A preferred process for depolymerizing waste plastic materials and producing pyrolysis products includes the following steps:

[0035] (a) In an oxygen-free gas, a mixture comprising waste plastic material is fed into a feeding system comprising at least one screw extruder (1) heated in the melting temperature range of the plastic material;

[0036] (b) Molten plastic material from an extruder is fed into a first depolymerization reactor (2), which is a continuously stirred tank reactor operated at a temperature range of 280-600°C and a pressure range of 1-10 barg, in which depolymerization occurs to form gaseous effluent and liquid effluent.

[0037] (c) At least a portion of the liquid effluent generated in the first reactor (2) is directed to the carbon treatment section (6), and the gaseous effluent from the reactor (2) is fed to the condensation unit (3), from which gaseous and liquid flows are generated;

[0038] (d) The gaseous flow from the first condensing unit (3) is directed to the second condensing unit (5) which operates in a temperature range lower than that of the first condensing unit, and the liquid flow from the condensing unit (3) is directed to the second depolymerization reactor (4), which is a continuous stirred tank reactor operated in a temperature range of 280-600°C and a pressure range of 1-10 barg, in which depolymerization occurs to form gaseous effluent and liquid effluent;

[0039] (e) The gaseous effluent from the depolymerization reactor (4) is discharged and fed into the second condensation unit (5), and at least a portion of the liquid effluent from the depolymerization reactor (4) is recycled to the first depolymerization reactor (2);

[0040] A further feature of the process is the recovery of pyrolysis products from the condensation unit (5), and at least one of the depolymerization reactors (2) and (4) operates in the presence of a depolymerization catalyst.

[0041] Preferably, the process is carried out in a continuous mode.

[0042] In stage (a), the feeding system allows the waste plastic material to be fed into the reactor (2), preferably in a continuous mode. Care should be taken to avoid introducing oxygen-containing gases into the system. Barriers to potentially oxygen-containing gases can be achieved in various ways, such as nitrogen covering or a vacuum system connected to the extruder barrel.

[0043] More specifically, the waste plastic mixture is fed into the feeding system of the depolymerization reactor (2) through a hopper or two or more hoppers connected in parallel, and the oxygen present in the waste plastic material gas is substantially eliminated inside the hopper.

[0044] The process according to the invention is highly flexible and can feed a wide range of plastic waste compositions, for example, heterogeneous mixtures of waste plastic materials (called Plasmix in Italy) in which polyolefins are the most abundant component, but for which further sorting steps are no longer economical. In particular, when pyrolysis products are recycled back to the cracking / refining unit, it is preferable to depolymerize plastic waste mixtures in which the polyolefin (PE and PP) content is equal to or greater than 70 wt%.

[0045] Waste plastic materials preferably undergo a pretreatment stage, in which they are heated and melted and, where possible, mixed with additives, which may be alkaline materials. Through melt pretreatment, heterogeneous mixtures of different types of waste plastics can be transformed into a large quantity of homogeneous plastic composite materials. Therefore, this pretreatment is also preferred for pyrolysis without additives.

[0046] The heating temperature in the pretreatment stage is appropriately set according to the type and content of plastics contained in the waste plastic material, thereby inhibiting the pyrolysis of the plastic material to be treated. Such temperatures are typically in the range of 100°C-300°C, preferably 150°C-250°C. At temperatures approaching 300°C or higher, HCl is eliminated from any PVC resin that may be present.

[0047] If waste plastic materials are mixed with alkaline materials during the melting / kneading pretreatment process, the resulting HCl gas can be removed and continuously neutralized or captured through the exhaust system. For the melting operation, a conventional kneader, an extruder with a screw, or similar equipment can be used. Preferably, the plastic waste is fed into the depolymerization reactor via an extruder.

[0048] The extruder melts the plastic waste material, bringing it to a high temperature (250-350°C) and injects it into the first depolymerization reactor (2). The extruder can receive the plastic waste cut into small pieces into the feed hopper, transport the flow in the molten section, and heat the polymer through a combination of mixed energy and heat provided by the barrel heater.

[0049] Additives can be selectively incorporated into the melt to reduce the corrosivity of the received plastic waste or to improve the conversion process in the reaction section.

[0050] During the extrusion process, one or more degassing steps can be anticipated to remove residual moisture present in the product.

[0051] Before being fed into reactor (2), the melt stream can be filtered to remove solid impurities present in the plastic waste.

[0052] Depending on the amount and particle size of solid impurities, several designs for melt filter units can be applied.

[0053] It is preferable to use a self-cleaning melt filter that can operate for extended periods (days) without human intervention to replace the filter element.

[0054] A preferred design for a melt filter is based on a circular perforated plate as the melt filter element, perforated by laser or by machining according to the openings, in which solid contaminants accumulate. The accumulation of impurities can increase the pressure differential across the melt filter. For in-line cleaning of the filter element, a rotating scraper removes the accumulated impurities and directs them to a discharge port, which is opened briefly to remove process contaminant material.

[0055] This cycle can be repeated several times (up to several days of operation) without human intervention or the need to stop production for the time required to replace the filter element.

[0056] Another option for self-cleaning melt filters is based on the application of a continuous filter belt through which the polymer flow passes. Impurities accumulate on the metal filter, creating an increase in pressure. Consequently, the clogged portion of the filter belt is pushed out of the polymer channel area and then inserted into the cleaning section.

[0057] The process is automated and allows for long-term operation (up to several days) without human intervention or the need to stop production for the time required to replace filter elements.

[0058] Any extrusion system can be used, such as a single-screw extruder, a twin-screw extruder, a twin-screw extruder with a gear pump, or a combination thereof.

[0059] In step (b), the depolymerization reactor (2) is preferably a stirred vessel operating in a temperature range of 300-550°C, more preferably 350-500°C.

[0060] The operating pressure is preferably maintained in the range of 2.0-8 barg, more preferably in the range of 2.5-7 barg.

[0061] To improve material flowability, in a preferred embodiment, the melt of waste plastic entering the reactor is premixed with hydrocarbon oil, preferably recycled oil from the first condensation unit, in a dedicated container to promote melt dissolution into the depolymerization reactor. In this case, the oil / melt volume ratio can be 0.1:1 to 1:1.

[0062] The depolymerization reactor (2) preferably has a cylindrical portion and, more preferably, a circular bottom.

[0063] Preferably, it has a mixer mounted on the vertical axis of the reactor, which is operated by a geared motor that allows the mixer blades to rotate to keep the system in a stirred state. The design of the mixer and the power of the motor can vary in terms of the reactor contents, volume, and shape; however, as a non-limiting example, a power of 0.2-4 kW / m³ is preferred. 3 Preferred power is 0.2-2kW / m³. 3 More preferably 0.3-1.5kW / m 3 The power input operates the reactor.

[0064] The reactor is heated to a temperature range of 300°C to 570°C by heat transfer caused by the molten salt flow.

[0065] The molten salt feed circuit (not shown) is constructed to prevent molten salt leakage. The molten salt is molten, evaporated salt, preferably a mixture of sodium nitrate and potassium nitrate, and even more preferably in a weight ratio of 2:3 to 3:2. The evaporated salt receives heat from a dedicated furnace, which can be electric or fuel-powered. In the latter case, some of the recovered oil from the condensation unit (5) can be used as feed into the furnace. In alternatives or combinations, heat can be generated by the combustion of gaseous or liquid hydrocarbons. Gaseous hydrocarbons are preferred.

[0066] Preferably, the heat associated with the molten salt is transferred to the depolymerization reactor by circulating the molten salt through a jacket surrounding the entire reactor and / or by feeding it into an external heat exchanger.

[0067] In both cases, the salt is circulated using a circulating pump. A series of fins ensures uniform distribution of the molten salt flow within the jacket and maximizes the heat exchange coefficient.

[0068] The depolymerization process occurring within the reactor produces molecules with reduced chain lengths and lower boiling points. This continuously operating chain-breaking mechanism, particularly near the reactor wall, produces increasingly smaller gaseous molecules under operating temperatures and pressures.

[0069] As a result, the compositions within the reactor cover a wide range of hydrocarbons, from methane to heavier products, saturated and olefinic, with straight-chain or highly branched structures. Some aromatic products and fused-ring structures may also be present.

[0070] Those that remain liquid under operating conditions help reduce the mass viscosity of the liquid. As a result of the depolymerization process and feed composition, the contents of reactor (2) can be defined as the coexistence of a liquid slurry phase and a gas phase, wherein solids, particularly carbonaceous and inorganic substances, are dispersed in a liquid hydrocarbon mixture.

[0071] At least a portion of the liquid slurry phase is discharged from the reactor, preferably from the bottom of the reactor, and constitutes the liquid effluent sent to the carbon treatment section (6), which will be described in further detail.

[0072] From an operational perspective, it is preferable to trigger the discharge of the slurry phase from the bottom of the reactor by detecting the density of the liquid slurry when it reaches a predetermined value using a density sensor.

[0073] In a particular and preferred embodiment, a portion of the liquid slurry discharged from reactor (2) is optionally recirculated back to the top of the reactor via a circulation pump (7) and an external heater (8). As described above, heat is preferably supplied to the external heater via molten salt. This embodiment can provide increased homogeneity of the reactor contents and reactor heating.

[0074] According to a preferred embodiment, the liquid slurry portion recirculated to the reactor is discharged from a point on the reactor that is different from the discharge point of the liquid slurry portion sent to the carbon treatment.

[0075] According to another preferred embodiment, the liquid slurry portion recirculated to the reactor and the liquid slurry portion sent to the carbon treatment are both discharged from the same point and then separated sequentially.

[0076] The separation between the liquid slurry portion directed to the char treatment and the portion recycled to the reactor can be performed before or after the circulation pump (7). In the latter embodiment, the liquid slurry is first fed into a dedicated container equipped with lower and upper outlet points. The liquid portion directed to the char treatment (6) is discharged from the lower outlet point in a concentrated form, while the liquid portion to be recycled to the reactor (2) is discharged from the upper outlet point.

[0077] The gaseous phase of reactor (2) constitutes the gaseous effluent, which is sent to the condensation unit (3) for further processing.

[0078] The gaseous effluent comprises a mixture of light hydrocarbons, and may also include some heavy hydrocarbons and entrained carbon particles. The gaseous effluent is conveyed from the top of the reactor to a condenser (3), which is preferably operated at a pressure slightly lower than that of the reactor.

[0079] To suppress entrained carbon, the condenser (3) is better designed as a scrubbing tower. The condenser temperature is selected in such a way that heavy hydrocarbons are condensed and light hydrocarbons are released as a gaseous stream. The gaseous stream (H2 and light hydrocarbons) is then conveyed to another condensation unit (5) that operates at a lower temperature range than the condensation unit (3) for the recovered oil.

[0080] The operating temperature of the condenser unit (3) can also vary over a wide range depending on the operating pressure. The temperature, i.e., atmospheric pressure, can be 20°C to 200°C, more preferably 50°C to 200°C, and especially 60°C to 180°C. When a higher operating pressure is selected, the temperature range can of course be different.

[0081] In a specific embodiment, the condenser unit (3) operates at approximately 80°C and samples the condensed liquid for analysis using GC.

[0082] Due to the very high number of compounds, the analytical results were reported by grouping the obtained compounds according to their retention times using specific hydrocarbons as internal retention time references. The results showed the presence of approximately 2 wt% or more of compounds with retention times equal to or less than n-heptane, approximately 25 wt% or more of compounds with retention times between n-heptane and n-dodecane, a more abundant fraction of compounds with retention times higher than n-dodecane but lower than n-octacosane (70 wt% or less), and possibly small amounts of fractions with even higher retention times.

[0083] In a preferred configuration of the condensation unit (3), a partial condenser is installed at the top of the scrubber and operates in a temperature range below the temperature inside the tower. The condensate flows downwards by gravity as a return flow to the scrubber. The partial condenser can be installed as a separate unit or within the scrubber.

[0084] In an alternative preferred configuration, the pump recirculates the liquid collected at the bottom of the scrubber to the top of the tower. The recirculated liquid is cooled in a dedicated heat exchanger before being injected as reflux into the top of the scrubber.

[0085] The preferred hydrocarbon condensate having more than C7 carbon atoms constitutes the liquid flow delivered to the second depolymerization reactor (4) by a pump.

[0086] The second depolymerization reactor (4) is preferably of the same type as the first depolymerization reactor, and more preferably is a continuous stirred tank reactor.

[0087] Depolymerization is carried out within the same temperature range, but in order to limit the volatility of heavy hydrocarbons, it is preferable to operate at a pressure higher than that of the first reactor, particularly at 2-10 barg, preferably 3-9 barg, and more preferably 3-8 barg.

[0088] Because the feed to reactor (4) includes condensate from reactor (2), it contains fewer impurities and produces less carbon. Preferably, fresh catalyst is fed into reactor (4) through conduit (15).

[0089] According to the present invention, the catalyst can be selected from those that are active as depolymerization / cracking catalysts in thermocatalytic processes. In particular, it can be selected from metal oxides, heteropoly acids, mesoporous silica, aluminosilicate catalysts, such as hydrous kaolinite and kaolinite, and preferably from zeolites. Among them, synthetic Y-type zeolites and ZSM-5 are particularly preferred.

[0090] In a particularly preferred embodiment, the amount of catalyst feed is no more than 10 wt% relative to the plastic waste feed, preferably no more than 5 wt%, and particularly no more than 2 wt%.

[0091] In a preferred embodiment, the catalyst is injected into the second reactor as a powder dispersed in hydrocarbon oil, which is preferably a liquid pyrolysis product (oil) obtained from the condensation unit (3) or (5), and more preferably from the condensation unit (3).

[0092] Preferably, the catalyst slurry is prepared in a continuous stirred tank, wherein the catalyst is poured from a dedicated silo to maintain a constant concentration of the catalyst in the slurry.

[0093] The pyrolysis oil of the dispersed catalyst is preferably discharged from the condensation unit (3) to maintain a constant slurry level in the tank. Once ready, the catalyst slurry can be injected, preferably into the second reactor, preferably by means of a screw pump to maintain its constant level.

[0094] The liquid effluent from reactor (4) is preferably a highly concentrated hydrocarbon slurry, which preferably contains a depolymerization catalyst. It is discharged from the second reactor and returned to the first reactor via conduit (16). The same density control used in reactor (4) for discharging the slurry is also preferably operated in reactor (2).

[0095] The slurry density can be controlled by available methods such as gamma-ray measurement or Coriolis density meter. When the operating pressure of the first reactor is lower than that of the second reactor, the light hydrocarbons of the slurry entering the first reactor are expected to evaporate and be extracted together with the gaseous effluent generated in reactor (2).

[0096] Preferably, the amount of slurry recycled to the first reactor is 5-40% of the contents of the second reactor, more preferably 10-30% of the contents.

[0097] Also in reactor (4), which is a preferred embodiment, a portion of the liquid slurry discharged from the bottom of reactor (4) is recirculated back to the top of reactor by a circulation pump (12) through an external heater (13).

[0098] The gaseous effluent generated from the reactor (4) is transported to the condensation unit (5) for the recovery of pyrolysis products in the form of oil.

[0099] The condensing unit (5) preferably has a similar configuration to the condensing unit (3).

[0100] Preferably, the operating conditions of the condensing unit (5) are selected in such a way that they have a lower operating temperature and pressure than those of the condensing unit (3).

[0101] Specifically, the temperature can be 20-80°C, preferably 30-70°C. The pressure value should preferably be lower than that of the condensing unit (3) to allow non-condensable gases from unit (3) to enter unit (5) without further pressurization. The oil recovered from the condensing unit (5) is generally lighter than the oil recovered from the first condensing unit and may particularly have the following composition (GC determination):

[0102] - Approximately 10-15 wt% of the fractions with retention times equal to or less than that of n-heptane;

[0103] - Approximately 70-75 wt% of a fraction with retention time, consisting of n-heptane and n-dodecane, and

[0104] - Approximately 12-20 wt% of the product has a retention time higher than that of n-dodecane but lower than that of n-octacosane.

[0105] - No trace compounds with high retention times were found.

[0106] As described above, the liquid effluent discharged from the pyrolysis reactor (2) and directed to the carbon treatment section is in the form of a slurry. The slurry discharged from the bottom of the reactor is concentrated and preferably discharged continuously. Operating the pressurized reactor allows the concentrated slurry to be easily discharged to a lower pressure device without the use of additional discharge equipment. As described above, the slurry can be discharged through the bottom of the reactor, or, if present, through a line or container after the circulation pump (7).

[0107] Considering the process setup, the slurry flow is preferably continuous. The carbon content in the slurry can be 10-50 wt%, preferably 20-40 wt%.

Claims

1. A carbon processing device, comprising: - A first jacketed chamber (6a) is provided with an inlet conduit (6a-1) for feeding carbonaceous slurry and a stirring system (6b) capable of operating in a temperature range of 350-570°C, and further provided with a conduit (6b-1) for discharging gaseous effluent, and - A device (6c) for discharging concentrated slurry from the first jacket chamber (6a) and conveying it to the second stripping chamber (6d), which is capable of maintaining the slurry within the same temperature range as the first jacket chamber (6a) and is provided with a degassing system for removing gaseous effluent and generating discharged carbon. - The second stripping chamber (6d), which receives the discharged charcoal, is equipped with a stirring system (6d-1), a charcoal outlet (6d-2), a gas inlet (6d-3) located at the bottom of the second stripping chamber (6d), and a gas outlet (6d-4) for removing gaseous effluents stripped from the discharged charcoal. -A device (6e) for receiving dry charcoal from the second stripping chamber (6d) and conveying it to the third collection chamber (6f), which is capable of maintaining the dry charcoal in a temperature range of 60-100°C. - The third collection chamber (6f), which receives the dry charcoal, is equipped with a stirring system (6f-1) and an outlet for charcoal disposal operated by a valve (6f-2).

2. The carbon processing equipment according to claim 1, wherein the first jacket chamber (6a) operates in a temperature range of 350-570°C.

3. The carbon processing equipment according to claim 1, wherein the means for discharging concentrated slurry from the first jacketed chamber (6a) and conveying it to the second stripping chamber (6d) is a screw conveyor, which is jacketed and operates within the same temperature range as the first jacketed chamber (6a).

4. The carbon processing equipment according to claim 1, wherein the molten sun-dried salt circulates within the first jacket chamber (6a) and the jacket of the screw conveyor.

5. The carbon processing equipment according to claim 3, wherein the screw conveyor is composed of two different conveying mechanisms connected to each other, the lower end of the first lifting screw conveyor (6c-1) is integral with the bottom of the first jacket chamber (6a), and its upper end is positioned at a higher height relative to the lower end, the first lifting screw conveyor (6c-1) is connected to one end of the second screw conveyor (6c-2), and the other end of the second screw conveyor (6c-2) is connected to the upper part of the second stripping chamber (6d).

6. The carbon processing equipment according to claim 5, wherein both conveyors are jacketed and operate within the same temperature range in the first jacket chamber (6a).

7. The carbon treatment equipment according to claim 1, wherein the second stripping chamber (6d) is provided with a nitrogen inlet at the bottom and an outlet at the top for conveying the stripped gas to the condensation unit.

8. The carbon processing equipment according to claim 1, wherein the bottom of the second stripping chamber (6d) is provided with an outlet and a ball valve, the ball valve being used to discharge the dry carbon into a jacketed screw conveyor maintained in a temperature range of 60-100°C.

9. The carbon processing apparatus according to claim 1, wherein the jacketed screw conveyor is connected to a third collection chamber (6f), in which nitrogen is circulated through a gas inlet (6f-3) and a gas outlet (6f-4).

10. The carbon treatment apparatus according to claim 1, connected to the depolymerization apparatus, comprising: The feeding system contains waste plastic material, which includes at least one screw extruder (1) that heats the plastic material at its melting temperature. The first depolymerization reactor (2) receives molten plastic material. The first depolymerization reactor (2) is a continuous stirred tank reactor in which depolymerization occurs to form gaseous effluent and liquid effluent. The first depolymerization reactor (2) is provided with an outlet for guiding at least a portion of the liquid effluent generated in the first depolymerization reactor (2) to the carbon treatment section (6) and an outlet for discharging the gaseous effluent from the first depolymerization reactor (2). The first condensation unit (3) receives the gaseous effluent from the first depolymerization reactor (2), and is provided with means for transferring the gaseous product to the second condensation unit (5) which operates at a temperature lower than that of the first condensation unit and means for guiding the liquid flow from the first condensation unit (3) to the second depolymerization reactor (4). - The second depolymerization reactor (4) is a continuous stirred tank reactor in which depolymerization occurs to form gaseous effluent and liquid effluent. The second depolymerization reactor (4) is provided with a catalyst feed line, for guiding at least a portion of the liquid effluent generated in the second depolymerization reactor (4) to the outlet of the first depolymerization reactor (2), and for discharging the gaseous effluent from the second depolymerization reactor (4) and guiding them to the outlet of the second condensation unit (5).

11. A process for processing carbon-containing slurry, comprising: - The carbon-containing slurry is introduced into a first jacketed chamber (6a) equipped with a stirring system (6b), and the first jacketed chamber (6a) is operated to a temperature range of 350-570°C, thereby generating and discharging gaseous effluent and The concentrated slurry is discharged from the first jacket chamber (6a) and conveyed to the second stripping chamber (6d), while the slurry is maintained in the same temperature range as the first jacket chamber (6a), and the gaseous effluent formed therefrom is removed and the discharged carbon is produced. The discharged char is introduced into a second stripping chamber (6d), which is equipped with a stirring system (6d-1), a char outlet (6d-2), a gas inlet (6d-3) located at the bottom of the second stripping chamber (6d), and a gas outlet (6d-4) for removing gaseous effluents stripped from the discharged char. The dry char obtained in the second stripping chamber (6d) is fed into the third collection chamber (6f), while the dry char is maintained in a temperature range of 60-100°C. The dry charcoal is discharged from the third collection chamber (6f) through valve (6f-2) and disposed of.

12. The process according to claim 11, wherein the carbon content of the slurry is 10-50 wt% relative to the total weight of the slurry.

13. The process according to claim 11, wherein the carbon content of the slurry is 20-40 wt% relative to the total weight of the slurry.

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