System for separating gases, liquids and solid particles in materials

Abstract

Provided is an apparatus for pyrolyzing waste plastics into one or more hydrocarbon products, preferably at least one or more liquid hydrocarbon products, the apparatus comprising: a heating device, preferably a heat exchanger, for receiving and heating the waste plastics to pyrolysis temperatures; a separator vessel downstream of the heating device; the separator vessel comprising an inlet positioned to receive gaseous and liquid plastic waste at pyrolysis temperatures from the heating device; an upper outlet for exiting the gaseous materials; and a hollow body having a substantially conical bottom, the substantially conical bottom having an opening angle of about 30° to about 70°.

Description

Detailed Description of the Invention

[0001] [Field of the Invention]

[0001] The present invention generally relates to methods and apparatus for treating waste plastics by pyrolysis, and the products obtained by these methods and apparatus. More particularly, the present invention relates to methods and apparatus for treating preheated streams of plastics and plastic-derived hydrocarbons undergoing pyrolysis. More particularly, the present invention relates to effective phase separation and / or completion of pyrolysis of plastic-derived hydrocarbons. Furthermore, the present invention relates to systems for separating gases, liquids, and optionally solid particles in materials. Furthermore, the present invention relates to methods and systems for separating products obtained from cracking long-chain hydrocarbons, and in particular, to methods and systems for treating plastics and polyolefins by cracking.

[0002] [Background of the invention]

[0002] Modern society generates large amounts of waste plastic. Although plastic recycling is becoming increasingly efficient and effective, the reality is that much of the waste plastic cannot be effectively or efficiently recycled and is discarded in landfills, where it can take years to decompose, or it can be lost to the environment, where it can cause damage to ecosystems.

[0003]

[0003] However, plastic materials are made from essentially useful compounds that can be used as is and / or converted for (re)use. For example, fuels such as diesel can be derived from waste plastics, or waste plastics can be converted into raw materials suitable for the synthesis of new materials, such as new plastics, other hydrocarbon materials, etc. Materials recovered from waste plastics can be useful to at least partially replace hydrocarbons more traditionally obtained from natural gas or mineral oil.

[0004]

[0004] The output of plastic-to-chemical plants typically includes light hydrocarbons (LHC), heavy hydrocarbons (HHC), charcoal, and non-condensables (gases). Currently, LHC, HHC, or a mixture thereof are the most desired products, but this is market dependent.

[0005]

[0005] The LHC and HHC fractions are required by the industry to meet certain chemical and physical specifications, such as vapor pressure, initial boiling point, final boiling point, flash point, viscosity, cloud point, and cold filter plugging point. While different qualities may be desired by different customers or end uses, it is important for plastics-to-chemicals plants to produce products of consistent quality. The final quality of the product fractions is controlled by distillation columns, such as those commonly used and well-known in the petrochemical industry. It is desirable for the light and heavy hydrocarbon fractions to be relatively pure so that they do not contain significant amounts of high-boiling compounds. Such high-boiling compounds can increase the cold filter plugging point and cloud point, and are often unacceptable to purchasers of pyrolysis oil.

[0006]

[0006] In plastics-to-chemicals plants, the input is raw plastics, which may consist mostly of polyethylene and polypropylene if domestically sourced. These plastics, made from very long chain hydrocarbons, are then cracked into shorter chains, forming a wide range of molecules with various chain lengths. These mixtures can be distilled into various fractions, as is known, determined by temperature.

[0007]

[0007] A known process in the art for converting waste plastics, among others, into diesel, is the thermochemical decomposition process of pyrolysis. Pyrolysis is the thermal decomposition of waste plastics in an inert atmosphere. In effect, the long polymer chains of the plastic polymers are cracked by heating, yielding shorter hydrocarbon chains that are generally more useful as products.

[0008]

[0008] Pyrolysis is the preferred method for carrying out the thermochemical decomposition of waste plastic materials. Various attempts have been made to provide industrially cost-effective pyrolysis of waste plastics.

[0009]

[0009] Industrially useful results have been obtained using the techniques discussed in patent publications U.S. Patent Application Publication No. 2018 / 0010050 and WO 2021053139, the contents of which are incorporated herein by reference.

[0010]

[0010] U.S. Patent Application Publication No. 2018 / 0010050 discusses a method for recovering hydrocarbons from plastic waste, particularly polyolefin-rich waste, by pyrolysis without the use of a catalyst. The process involves melting the plastic waste in two heating devices and mixing a stream from a cracking reactor with the inflowing molten plastic waste from the first heating device. The heated and molten plastic is sent to the cracking reactor, where the plastic material is cracked. The cracked material is then distilled into diesel and low-boiling substances.

[0011]

[0011] WO 2021 / 053139, which offers some advancements over U.S. Patent Application Publication No. 2018 / 0010050, discusses, among other things, a method for cracking long-chain hydrocarbons from plastic-containing waste, the method including the steps of providing a material containing long-chain hydrocarbons, heating a specific volume of the material containing long-chain hydrocarbons to a cracking temperature at which the hydrocarbon chains of the material begin to crack into shorter chains, and, for the specific volume having a temperature above the cracking temperature, exposing the specific volume to heat not more than 50°C above the temperature of the specific volume. After the specific volume of material has been exposed to heat, WO 2021 / 053139 sends the partially cracked molten plastic stream to a gas-liquid separation structure. The separation structure, also referred to as a reactor, includes a separation zone including a gas-liquid phase boundary and a settling zone where heavy hydrocarbons and / or solid carbon, and potentially other solids such as aluminum, sand, and soil, accumulate.

[0012] While good results have been achieved based on the foregoing techniques, there is room for further improvement; for example, it would be useful to provide a system and process that is more versatile than systems previously attempted.

[0013]

[0013] EP 2876146 discusses tested technology for recovering hydrocarbons from polyolefin plastic recycle by pyrolytic cracking, which process includes the steps of introducing the plastic recycle into a mixing vessel under inert gas and mixing with diesel oil, removing water vapor in a first heating zone, removing acid gases in a second heating zone, liquefying the not yet melted plastic recycle in a third heating zone, cracking the plastic recycle in a cracking reactor at about 400 degrees Celsius, partially condensing to prevent the release of paraffins, and fractionating the cracked product.

[0014] The present invention has the general object of improving the overall system of such pyrolysis processes and apparatus, and the improvements can preferably include one or more of the following aspects:

[0015] In one aspect, it is an object of the present invention to provide alternatives, preferably improvements, to pyrolysis processes and apparatus. These alternatives, preferably improvements, may address systems for separating gases, liquids, and solid particles in plastic cracking streams, and / or cracking long-chain hydrocarbons. It is also an object of the present invention to provide improved methods for cracking long-chain hydrocarbons.

[0016] In one aspect of the present invention, it may be useful to reduce or limit char formation in vessels that separate pyrolyzed gaseous hydrocarbons from liquid, partially pyrolyzed plastic material.

[0017] In another aspect of the present invention, it may be useful to achieve better control of the product fractions sent to distillation and which fractions are ultimately distilled, for example, to achieve a more commercially useful ratio of non-condensables, light hydrocarbon fraction, and heavy hydrocarbon fraction of the product stream.

[0018] In another aspect of the present invention, it may be desirable to improve the reliability of the process.

[0019] In another aspect of the present invention, it may be desirable to improve or limit system downtime.

[0020] In another aspect of the present invention, it may be advantageous to expand or diversify the product streams available for production by the pyrolysis process, for example, to produce heavier fractions such as paraffins in controllable amounts.

[0021] A non-limiting object of the present invention is to provide an efficient, versatile, and / or robust process and apparatus for converting waste plastics into useful product streams, such as non-condensable gases, light hydrocarbons, heavy hydrocarbons, paraffins, bitumen, tar, and other similarly derivable fractions. In this regard, the present invention may, for example, address one or more of the problems discussed above, or at least provide a useful option in the art.

[0022]

[0022] Attempts have been made in the past to achieve effective pyrolysis of waste plastics.

[0023]

[0023] Patent publication WO 11077419, which refers to a process for treating waste plastics, discusses an example in which plastics are melted and then pyrolyzed in an oxygen-free atmosphere in a jacket-heated pyrolysis vessel to form pyrolysis gases. The pyrolysis gases flow upward through a pipe directly connecting the pyrolysis chamber to the contactor vessel and contact the plates of the contactor vessel, thereby condensing some of the long-chain gas components. The condensed liquid flows downward through the same pipe and directly back into the pyrolysis zone. The condensed liquid is then reheated in the pyrolysis zone and further pyrolyzed. The short-chain gas components exit the contactor in gaseous form and are directed to distillation.

[0024]

[0024] WO 11077419 explains that when the batch ends, an increase in the load on the pyrolysis chamber agitator indicates that char drying is occurring and the process is complete. The pyrolysis chamber is then purged by reversing the operation of the double-helix agitator blade to remove the char, and nitrogen is pumped upward through the contactor and discharged directly to the thermal oxidizer to wash away any remaining hydrocarbons; during this stage, the pyrolysis vessel and contactor are isolated from the rest of the system. Such processes and systems can be problematic and suboptimal. For example, including an agitator in the pyrolysis chamber and directly jacketing and heating the pyrolysis chamber are necessary, albeit complicated. This system also uses a specific type of jacket-cooled contactor with a sloped, open-ended cooling contactor baffle plate to return condensed hydrocarbons from the contactor directly to the pyrolysis chamber through the same tubes through which the pyrolysis gases entered the contactor. This can be complicated; the pyrolysis process results in batch completion with a dry char (carbon) product and associated purging, which results in extended downtime of the pyrolysis reactor.

[0025] Previous attempts have involved placing a partial condenser directly on top of the pyrolysis vessel to return heavy hydrocarbons for further cracking. Some of these attempts have been found to be less than optimal in versatility, robustness, and efficiency. Without being bound by theory, engineering studies have demonstrated that returning condensed liquid from the partial condenser directly to the pyrolysis reactor vessel can result in temperature mismatches and heat losses in the pyrolysis zone, requiring complex heat input in the pyrolysis zone with the potential for hot spots, carbonization, complex mixing, and / or energy losses. It would be desirable to provide a process and system that is less susceptible to such drawbacks.

[0026] Another example is discussed in Swiss Patent Application Publication No. 708681, which refers to a process for recovering hydrocarbons from polyolefin plastic recycle by pyrolytic cracking. The plastic recycle is introduced into a mixing vessel under inert gas and subjected to the following steps: mixing with diesel oil, removing steam in a first heating zone, removing acid gases in a second heating zone, liquefying the not-yet-melted plastic recycle in a third heating zone, cracking the plastic recycle in a cracking reactor at about 400°C, partially condensing to prevent the release of paraffins, and fractionating the cracked product.

[0027] The partial condenser in Swiss Patent Application Publication No. 708681 is separate and remote from the pyrolysis reactor, and a connecting pipe leads the pyrolyzed gases from the pyrolysis reactor to the partial condenser. The partial condenser is adjusted so that heavy hydrocarbons not of the desired product characteristics condense and are returned via a separate pipe to the third heating zone, where these pyrolyzed gases can be further cracked. The additional cracking loop reduces excessive heavy hydrocarbons in the product.

[0028]

[0028] Attempts to implement concepts related to those disclosed in CH 708681 A1 have been found to be feasible to produce, but have shown some instability and inefficiency in the pyrolysis, for example requiring complex heating in the pyrolysis zone. Furthermore, the system of CH 708681 A1 can be complicated to implement due to the pressure difference between the partial condenser and the heating zone to which the heavy hydrocarbons are returned.

[0029]

[0029] Other attempts have included U.S. Patent No. 10,160,920, which describes a continuous cracking process for thermally cracking hydrocarbon feedstocks in cascade cracking units; U.S. Patent Application Publication No. 2007227874, which discusses a method for recovering fractionated hydrocarbons from recycled plastics; and U.S. Patent No. 5,580,443, which discusses a process for thermally cracking low-quality feedstocks containing a significant proportion of heavy fractions, such as high-boiling fractions.

[0030] All references, including any patents or patent applications, cited in this specification are hereby incorporated by reference. No admission is made that any reference constitutes prior art.

[0031] [overview]

[0031] The invention is defined in the independent claims, while further aspects of the invention are set out in the dependent claims, the drawings, the following description and clauses.

[0032] According to one aspect of the present invention there is provided a method for the pyrolysis of plastic material, the method comprising: heating the plastic material to a pyrolysis temperature to result in a fluid stream of at least partially pyrolyzed material comprising liquid and gaseous hydrocarbons; injecting the fluid streams of liquid and gaseous hydrocarbons, preferably under gravity, into a gas-liquid separation vessel where the gaseous and liquid materials diverge; discharging the gaseous material from the separation vessel for processing said gaseous material into hydrocarbon products; amassing the liquid at the bottom of a separation vessel and subjecting the liquid to further pyrolysis. wherein a fluid stream of liquid and gaseous hydrocarbons is injected to generate a vortex or cyclone fluid flow in the separation vessel.

[0033] Vortex or cyclone flow can help achieve efficient phase separation of the flow by pushing the denser liquid to the periphery and the gas rising upward. Vortex or cyclone flow can further aid in heat distribution and / or effective settling of solid particles in the liquid.

[0034]

[0034] The liquid and entrained solids (and / or solids such as carbon generated during pyrolysis) can thus collect at the bottom of the separator vessel, where the liquid and entrained solids can be further processed and / or separated.

[0035]

[0035] The injection of the fluid stream is preferably below the level of the accumulated liquid in the separator vessel, which can help to create a vortex or cyclone effect in the accumulated liquid.

[0036] The fluid streams of liquid and gaseous hydrocarbons are preferably injected into the gas-liquid separation vessel substantially tangentially to the interior surface of the separation vessel, and preferably the separation vessel has a substantially circular cross section, at least at the injection point, which injection can further assist in creating a vortex or cyclone effect in the accumulated liquid.

[0037] A portion of the liquid material stored in the separation vessel can be removed from the separation vessel, for example by suction or pumping, reheated to pyrolysis temperatures, and returned to the separation vessel as a second inlet fluid stream containing liquid and gaseous hydrocarbons. This can help reduce the need to heat the interior of the separation vessel to achieve pyrolysis. The second fluid stream can preferably be injected into the gas-liquid separation vessel separately from or together with the first stream.

[0038] In one aspect of the present invention, there is provided an apparatus for pyrolyzing waste plastics into one or more hydrocarbon products, preferably at least one or more liquid hydrocarbon products, the apparatus comprising: a heating device, preferably a heat exchanger, for receiving and heating the waste plastic to pyrolysis temperatures; a separator vessel downstream of the heating device, the separator device comprising: an inlet positioned to receive gaseous and liquid plastic waste at pyrolysis temperatures from the heating device; an upper outlet for the gaseous material to exit; and Lower outlet for liquid material Equipped with An apparatus is provided in which an inlet is arranged to inject gaseous and liquid plastic waste from a heating device to generate a vortex or cyclone fluid flow in the separation vessel.

[0039] The inlet(s) for the hot liquid plastic waste material are preferably arranged to inject the material substantially tangentially to the inner surface of the separation vessel, the separation vessel having a substantially circular cross section, at least at the injection point or level, which can assist in achieving a vortex or cyclone.

[0040]

[0040] The separation vessel is preferably elongated and vertically arranged so that the pyrolyzed gaseous and liquid materials separate under gravity, with the pyrolyzed gaseous material proceeding upward to the upper outlet and the liquid material proceeding downward.

[0041] In one aspect of the present invention there is provided a method for the pyrolysis of plastic materials, the method comprising: heating the plastic material to a pyrolysis temperature to result in a fluid stream of at least partially pyrolyzed material comprising liquid and gaseous hydrocarbons; passing the fluid stream of liquid and gaseous hydrocarbons, preferably under gravity, to a gas-liquid separation vessel where the gaseous and liquid materials separate; discharging the gaseous material from the separation vessel for processing said gaseous material into hydrocarbon products; collecting the liquid in the bottom of a separation vessel and subjecting the liquid to further pyrolysis; withdrawing a portion of the accumulated liquid material from the separation vessel, heating the withdrawn liquid to pyrolysis temperatures, and returning the liquid to the separation vessel as a fluid stream comprising liquid and gaseous hydrocarbons. wherein the accumulated liquid is withdrawn via an outlet within the separation vessel, preferably an outlet substantially radially central to the separation vessel.

[0042] This method can help achieve removal of liquid from the separation vessel having a relatively low solid particle content compared to conventional attempts to remove liquid from the interior walls, possibly for reheating. Preferably, the outlet for withdrawing the trapped liquid is positioned approximately in the center of the vortex or cyclone flow generated in the vessel, where a quiescent zone of little liquid movement can occur.

[0043] A shroud may be provided at least partially radially surrounding the liquid outlet, preferably partially or completely submerged in the accumulated liquid, which may assist in the exclusion of solid particulates and / or in stirring up the quiescent zone. Preferably, the shroud at least partially isolates the liquid outlet from the radially outer cyclone or vortex flow in the separation vessel.

[0044] The outlet for the accumulated liquid may preferably comprise a vertically disposed cylinder of preferably circular cross section having an opening at the top end of the cylinder and an opening at the bottom end of the cylinder, the opening at the top end preferably being smaller than the opening at the bottom end, thereby aiding in effective liquid removal, while still allowing upper gas bubbles to escape into the gas zone of the container.

[0045] In one aspect of the present invention, there is provided an apparatus for pyrolyzing waste plastics into one or more hydrocarbon products, preferably at least one or more liquid hydrocarbon products, the apparatus comprising: a heating device, preferably a heat exchanger, for receiving and heating the waste plastic to pyrolysis temperatures; a separator vessel downstream of the heating device, the separator device comprising: an inlet positioned to receive gaseous and liquid plastic waste at pyrolysis temperatures from the heating device; an upper outlet for the gaseous material to exit; and Lower outlet for liquid material Equipped with An apparatus is provided in which a lower outlet for exiting the liquid material is positioned within the separation vessel, preferably substantially radially centrally.

[0046]

[0046] In this apparatus, the inlet is arranged to inject gaseous and liquid plastic waste from the heating device substantially tangentially to the inner surface of the separation container, and preferably the separation container has a substantially circular cross-section, at least at the injection point or injection level.

[0047] The separation vessel of the present invention is preferably elongated and vertically oriented, which helps the pyrolyzed gaseous and liquid materials separate under gravity, with the pyrolyzed gaseous material proceeding upward to the upper outlet and the liquid material proceeding downward.

[0048]

[0048] The liquid outlet is preferably located below the working liquid level of the separation vessel and is preferably submerged in use.

[0049] In one aspect of the present invention, there is provided an apparatus for pyrolyzing waste plastics into one or more hydrocarbon products, preferably at least one or more liquid hydrocarbon products, the apparatus comprising: a heating device, preferably a heat exchanger, for receiving and heating the waste plastic to pyrolysis temperatures; a separator vessel downstream of the heating device, the separator vessel comprising: an inlet positioned to receive gaseous and liquid plastic waste at pyrolysis temperatures from the heating device; an upper outlet for the gaseous material to exit; and Hollow body with substantially conical base Equipped with Apparatus is provided in which the substantially conical bottom has an opening angle of about 30° to about 70°, preferably about 50° to about 70°, preferably about 55° to about 65°, and more preferably about 60°. The angle of the cone can help to effectively submerge the particulate material in the high solids concentration portion of the liquid, while still minimizing clogging of the lower outlet.

[0050] In various aspects of the present invention, the separation vessel has an inner surface, preferably the inner surface of the lower conical portion, with a surface roughness of less than Ra 25 μm, preferably less than Ra 15 μm, more preferably less than Ra 12 μm, even more preferably less than Ra 10 μm, and even more preferably less than Ra 6 μm. A smooth surface can not only effectively settle particulates but also help reduce fouling.

[0051] In one aspect of the present invention there is provided a method for the pyrolysis of plastic materials, the method comprising: heating the plastic material to a pyrolysis temperature to result in a fluid stream of at least partially pyrolyzed material comprising liquid and gaseous hydrocarbons and solid carbon particles; directing the fluid stream, preferably under gravity, to a gas-liquid separation vessel where the gaseous and liquid materials separate; discharging the gaseous material from the separation vessel for processing said gaseous material into hydrocarbon products; collecting the liquid with entrained solid carbon particles at the bottom of a separation vessel and subjecting the liquid to further pyrolysis to produce further solid carbon particles; allowing the solid carbon particles to settle to the bottom of a separation vessel, the bottom being substantially conical, the substantially conical bottom having an opening angle of about 30° to about 70°; and withdrawing at least a portion of the mixture of hydrocarbons and solid carbon particles from the bottom conical portion. A method is provided, comprising:

[0052] In one aspect of the present invention there is provided a method for the pyrolysis of plastic materials, the method comprising: heating the plastic material to a pyrolysis temperature to result in a fluid stream of at least partially pyrolyzed material comprising liquid and gaseous hydrocarbons; passing the fluid stream of liquid and gaseous hydrocarbons, preferably under gravity, to a gas-liquid separation vessel where the gaseous and liquid materials separate; discharging the gaseous material from the separation vessel for processing said gaseous material into hydrocarbon products; collecting the liquid in the bottom of a separation vessel and subjecting the liquid to further pyrolysis; and determining the liquid level in the separation vessel by radar, radioactivity, temperature, mass and / or pressure measuring devices; A method is provided, comprising:

[0053] Preferably, the liquid level in the separation vessel is controlled by adjusting the rate of pyrolysis, preferably by temperature control. The liquid level can alternatively or simultaneously be controlled by the rate of introduction of fresh feed.

[0054] Maintaining a predetermined level in the separation vessel can help achieve efficient cracking, a desired product output, and can protect operating equipment such as (centrifugal) pumps from damage. Providing a predetermined liquid level in the separation vessel can also aid in an efficient and / or safe start-up procedure for the system.

[0055] In one aspect of the present invention, there is provided an apparatus for pyrolyzing waste plastics into one or more hydrocarbon products, preferably at least one or more liquid hydrocarbon products, the apparatus comprising: a heating device, preferably a heat exchanger, for receiving and heating the waste plastic to pyrolysis temperatures; a separator vessel downstream of the heating device, the separator vessel comprising: an inlet positioned to receive gaseous and liquid plastic waste at pyrolysis temperatures from the heating device; an upper outlet for the gaseous material to exit; and A liquid level measurement system for determining a liquid level in a separation vessel, the liquid level measurement system comprising one, more than one or all of the devices selected from the group consisting of a radar measurement device, a radioactivity measurement device, a temperature measurement device, a mass measurement device and a differential pressure measurement device. An apparatus is provided comprising:

[0056] In one aspect of the present invention there is provided a method for the pyrolysis of plastic materials, the method comprising: heating the plastic material to a pyrolysis temperature to result in a fluid stream of at least partially pyrolyzed material comprising liquid and gaseous hydrocarbons and solid carbon particles; directing the fluid stream, preferably under gravity, to a gas-liquid separation vessel where the gaseous and liquid materials separate; discharging the gaseous material from the separation vessel for processing said gaseous material into hydrocarbon products; collecting the liquid with entrained solid carbon particles at the bottom of a separation vessel and subjecting the liquid to further pyrolysis to produce further solid carbon particles; allowing the solid carbon particles to settle to the bottom of a separation vessel; and withdrawing at least a portion of the mixture of hydrocarbons and solid carbon particles from the bottom of the separation vessel and recycling said mixture of hydrocarbons and solid carbon particles to said bottom; A method is provided, comprising:

[0057]

[0057] Recirculating the mixture can provide more efficient drainage of the particle-rich liquid, thus providing a more robust and low maintenance equipment and process, and can help reduce or prevent gelling, clumping, coagulation, etc. of the dense material. This recirculation can help prevent plugging of the separation vessel and can aid in in-process carbon removal.

[0058] Preferably, in this process, i.e., the step of withdrawing and recycling the mixture of hydrocarbons and solid carbon particles, the hydrocarbons and solid carbon particles are withdrawn from the bottom of the separation vessel, recycled, and injected into the separation vessel at a location in the separator vessel above the bottom withdrawal point and below the liquid level, preferably below an outlet for withdrawing a portion of the accumulated liquid material having a lower concentration of solid particles from the separation vessel. This step circulates the high concentration material to a lower concentration zone, helping to reduce clogging.

[0059] It is preferred to measure a property of the extracted material, such as a property indicative of the concentration or particle size of coke, charcoal or solid particles, which can be done by density analysis, turbidity analysis, viscosity analysis, spectroscopic analysis, radioactivity analysis and / or ultrasonic analysis.

[0060] Preferably, the extracted solids-containing liquid can be heated before being returned to the separation vessel.

[0061] In one embodiment, there is provided an apparatus for pyrolyzing waste plastics into one or more hydrocarbon products, preferably at least one or more liquid hydrocarbon products, the apparatus comprising: a heating device, preferably a heat exchanger, for receiving and heating the waste plastic to pyrolysis temperatures; a separator vessel downstream of the heating device, the separator device comprising: an inlet positioned to receive gaseous and liquid plastic waste at pyrolysis temperatures from the heating device; an upper outlet for the gaseous material to exit; a carbon outlet at the base of the separator vessel for withdrawing the mixture of hydrocarbons and solid carbon particles from the bottom of the separator vessel; one or more recirculation nozzles positioned at the bottom of the separation vessel for injecting at least a portion of the withdrawn mixture into the separation vessel; An apparatus is provided comprising:

[0062]

[0062] In order to determine the properties of the withdrawn liquid, the apparatus may be provided with a sample point or station for determining a property of the withdrawn mixture, preferably a property indicative of the concentration or size of solid carbon particles in said mixture, preferably comprising at least one sensor selected from a density sensor, a turbidity sensor, a flow sensor, a spectrometer, a radioactivity sensor and / or an ultrasonic sensor. Monitoring can assist in controlling the process and in determining when cleaning or maintenance is required.

[0063] In some embodiments, it may be useful to reduce or limit char formation in the vessel separating the pyrolyzed gas from the liquid, partially pyrolyzed plastic material. In this regard, it may be useful to reduce, limit, or avoid direct heating of such vessels, e.g., heating of the vessel walls, or the inclusion of heating elements (such as heating coils) in such vessels. Preferred separator vessels of the present invention are unheated, e.g., are not provided with jacket heaters or internal heating elements. The introduced molten waste plastic stream can be supplied already at the pyrolysis temperature, eliminating the need for additional heating in the separation vessel. In some preferred embodiments, the liquid, partially pyrolyzed plastic material collected in the separation vessel is controllably removed from the separation vessel, preferably by a pump, and reheated to the pyrolysis temperature, preferably in a heat exchanger, before being returned to the separation vessel, optionally together with fresh feed. Thus, the removed liquid long-chain hydrocarbons can be subjected to further pyrolysis, decomposed into shorter-chain hydrocarbons, and ultimately exit via a partial condenser.

[0064]

[0064] The waste plastic feedstock for the present invention may preferably comprise polyethylene and / or polypropylene plastics. Preferably, the sum of polyethylene and polypropylene in the feedstock is at least 50% by weight of the weight of the feedstock, more preferably at least 60% by weight, even more preferably at least 75% by weight, and most preferably at least 90% by weight. These materials represent the majority of domestic plastic waste and can be processed by pyrolysis. The preferred plastics for the feedstock are polyethylene or polypropylene.

[0065] The feedstock may also contain polyvinyl chloride plastic, but the level of PVC may be limited to less than 10% by weight, preferably less than 5% by weight. PVC may be present at greater than 1% by weight, more preferably greater than 5% by weight. It may be preferred that PVC is substantially absent from the feedstock.

[0066] The raw material may also contain polyethylene terephthalate plastic, preferably more than 3% by weight, more preferably more than 4% by weight. The raw material preferably contains up to 20% by weight of PET plastic. Preferably, the content of polyethylene terephthalate plastic is up to 10% by weight, more preferably 5% by weight.

[0067] The feedstock may comprise up to 100% by weight polystyrene plastic. In embodiments, the feedstock may comprise at least 5% by weight polystyrene, more preferably 20% by weight, more preferably 50% by weight polystyrene.

[0068] The pyrolysis temperature may vary within a limited range depending on factors such as the composition of the raw materials and the operating pressure; preferably, the plastic material is heated to a pyrolysis temperature of 360°C or higher, about 390°C or higher, more preferably about 400°C or higher, up to about 450°C, although higher temperatures up to about 500°C or about 550°C may also be implemented. Pyrolysis of plastics may begin as early as about 360°C, and such temperatures may also be considered. However, pyrolysis is more pronounced above about 390°C, which may enable a more economically attractive process.

[0069] As used herein, the term "pyrolysis zone" refers to a zone in which the material being treated by a process or system (e.g., waste plastics or derivatives thereof generated by pyrolysis in the process or system) is at a pyrolysis temperature, e.g., a temperature of 360°C or higher, more preferably a temperature of 390°C or higher, and even more preferably a temperature of 400°C or higher. A pyrolysis zone is preferably a zone in a process or system in which the material being treated is at a temperature of about 360°C to about 550°C, more preferably about 390°C to about 500°C, and even more preferably about 400°C to about 500°C. Processes and systems may include pyrolysis zones of different activity. For example, there may be a primary pyrolysis zone, preferably at a temperature above 390°C, where the majority of the pyrolysis occurs, and a secondary pyrolysis zone, where the temperature is above 360°C but below 390°C. A pyrolysis zone is a zone in a process, system, or apparatus in which pyrolysis occurs or where pyrolysis conditions are created.

[0070] Pyrolysis, as is generally understood, is carried out in the absence of oxygen, most preferably under an inert atmosphere. Nitrogen gas can form the inert atmosphere. Prior to start-up, the system may be purged with nitrogen gas to form at least an initial inert atmosphere.

[0071]

[0071] The gas phase may preferably consist of pyrolysis gases substantially free of oxygen, optionally containing nitrogen.

[0072] The operating pressure of the separator vessel is preferably higher than ambient to ensure that ambient air does not enter the system. The pressure can be from 1 bar (absolute) to 5 bar (absolute), from 1 bar (absolute) to 3 bar (absolute), from 1 bar (absolute) to 2 bar (absolute), or from 1 bar (absolute) to 1.5 bar (absolute), or from 1 bar (absolute) to 1.05 bar (absolute).

[0073] The present invention preferably produces one or more hydrocarbon products, preferably including one or more of butane, propane, kerosene, diesel, fuel oil; light distillates such as LPG, gasoline, naphtha, or mixtures thereof; medium distillates such as kerosene, jet fuel, diesel, or mixtures thereof; heavy distillates and residues such as fuel oil, lubricating oil, paraffin, wax, asphalt, or mixtures thereof. The hydrocarbon products may be saturated, unsaturated, linear, cyclic, or aromatic. Additional products may include non-condensable gases including methane, ethane, ethene, and / or other small molecules. The products may be a source of feedstock for steam crackers in the production of plastics.

[0074] The terms "noncondensables" or "noncondensable gases," variously referred to, refer to hydrocarbon fractions that are too volatile to be condensed in the distillation section and that preferably exit the process as gases. Generally, noncondensable hydrocarbons in a thermal cracking process are considered to have from about 1 to about 7 carbon atoms. Noncondensables can include saturated, unsaturated, linear, cyclic, and / or aromatic hydrocarbons.

[0075] The term "light hydrocarbons" or "LHCs," as variously called, refers to the hydrocarbon fraction that is condensable in the process and thus obtainable as a liquid, but that contains short-chain molecules. Generally, LHCs in a pyrolysis process are considered to have from about 3 to about 8 carbon atoms, possibly with some smaller amounts of C2 and / or C10 molecules. LHCs can include saturated, unsaturated, linear, cyclic, and / or aromatic hydrocarbons.

[0076] The term "heavy hydrocarbons" or "HHCs," as variously referred to, refers to hydrocarbon fractions that are condensable in the process and therefore obtainable as liquids, generally having a longer chain composition than LHCs. Generally, HHCs in a pyrolysis process are considered to have at least about 7 carbon atoms (possibly with some smaller C6 molecules), preferably up to about 35 carbon atoms. A preferred range may include a low-range product of about 7 to about 20 carbon atoms, optionally with smaller C6 and / or C21 molecules. For the low-range product, the HHC end point may be about 430°C. Another preferred range may include a mid-range product of about 8 to about 28 carbon atoms. For the mid-range product, the HHC end point may be about 450°C. Another preferred range may include a high-range product of about 10 to about 35 carbon atoms. For the high-range product, the HHC end point may be about 550°C. HHCs can include saturated, unsaturated, linear, cyclic and / or aromatic hydrocarbons.

[0077] The reader skilled in working with petrochemicals will understand that there may be some variation in the boundaries between noncondensables, LHC, and HHC in a distillation process. The overlap and / or variation may depend, among other things, on the temperature, pressure, and flow settings selected, and product specifications can be adjusted to meet desired product qualities.

[0078] The features and advantages of the present invention may be understood with reference to the following drawings. [Brief explanation of the drawings]

[0079] [Figure 1] 1 shows an assembly for cracking long chain hydrocarbons. [Figure 2] 2 illustrates an embodiment of the separation vessel, partial condenser, and reboiler of FIG. 1 in more detail. [Figure 3] 1 illustrates an embodiment of a separator vessel. [Figure 4] 4 shows a side view of the separator vessel of FIG. 3. [Figure 5] 4 shows a side view of the separator vessel of FIG. 3. [Figure 6] 4 shows a side view of the separator vessel of FIG. 3. [Figure 7] 4 shows a cross-sectional view of the separator vessel of FIG. 3. [Figure 8] 4 shows a top view of the separator vessel of FIG. 3. [Figure 9] 4 shows the underside of the separator vessel of FIG. 3. [Figure 10] 4 shows an enlarged partial view of the lower portion of the separator vessel of FIG. 3. [Figure 11] 1 illustrates a schematic diagram of a reheat recycle loop for a separation vessel. [Figure 12] 4 shows an enlarged partial view of the lower part of the separation vessel of FIG. 3. [Figure 13] 1 shows a schematic representation of a lower part of a separation vessel provided with an internal liquid withdrawal outlet; [Figure 14] 1 shows a schematic representation of a lower part of a separation vessel provided with an internal liquid withdrawal outlet; [Figure 15] 1 shows a schematic representation of a lower part of a separation vessel provided with an internal liquid withdrawal outlet and an internal shroud; [Figure 16] 16A and 16B are schematic illustrations of liquid flow patterns around the shroud of FIG. 15; [Figure 17] 1 shows a schematic representation of the lower part of a separation vessel provided with a carbon and / or bitumen circulation loop; [Figure 18] 1 shows a schematic representation of a separation vessel provided with a liquid level temperature sensor; [Figure 19] 1 shows a schematic representation of a separation vessel provided with a liquid level radiation sensor; [Figure 20] 1 shows a schematic representation of a separation vessel provided with a load sensor;

[0080] Description and Exemplary Embodiments

[0099] It will be understood that for brevity and clarity of the figures, where considered appropriate, reference numerals may be repeated in the figures to indicate corresponding or analogous elements or steps. Furthermore, numerous specific details have been set forth in order to provide a thorough understanding of the embodiments described herein. However, those skilled in the art will understand that the embodiments described herein may be practiced without these specific details. Furthermore, this description should in no way be considered as limiting the scope of the embodiments described herein, but merely as an illustration of implementations of the various embodiments described herein. Following are descriptions of specific embodiments of the present invention, shown by way of example only and with reference to the drawings.

[0081]

[0100] 1 shows an apparatus comprising a heating device 11 and a separation vessel 12. The heating device 11 is in communication with the separation vessel 12 for supplying fluids (liquid and gas) to the separation vessel 12. More specifically, the heating device 11 supplies fluids containing (partially) cracked hydrocarbons in both gaseous and liquid states to the separation vessel 12 at pyrolysis temperatures.

[0082]

[0101] In some embodiments, the feeding device 7 is arranged to charge the heating device 11 with material containing long-chain hydrocarbons, such as waste plastics as discussed above. In some embodiments, the feeding device comprises an actuator 8 for heating and / or advancing the material containing long-chain hydrocarbons. In some embodiments, the actuator is a screw auger 8 arranged to advance, and preferably also heat, the material containing long-chain hydrocarbons. In some embodiments, the screw auger 8 moves the material, and internal friction of the material causes it to heat and melt. In further embodiments, the feeding device 7 includes a heating device, such as an electric heater, or a heating device filled with a heating medium, such as thermal oil. The feeding device 7 extrudes the material containing long-chain hydrocarbons into the heating device 11.

[0083]

[0102] A significant portion of the solid particulates result from the pyrolysis reaction, which is the production of charcoal or coke particles typical of pyrolysis. Other particulates may be present due to impurities in the initial plastic feed stream to the process, such as metal particles and other detritus, including organic matter. In the illustrated embodiment, four heating zones are shown. Heating zones 1, 2, 3, and 4 may each be a heat exchanger, preferably a tube-in-shell heat exchanger. Heating zones 1, 2, 3, and 4 form a flow path for the plastic material containing long-chain hydrocarbons. Heating zones 1, 2, 3, and 4 provide a continuous or gradual increase in exposure temperature along the flow path. Heating is preferably gradual to reduce or avoid char formation due to excessive temperature differentials.

[0084]

[0103] Heating device 11 heats and melts the raw plastic material, raising its temperature to the pyrolysis temperature. Cracking may begin in any of heating zones 1, 2, 3, or 4, but the majority of cracking in the heating zones preferably occurs in heating zone 4, which is the hottest of the four. The pyrolysis temperature can be 360°C or higher, more preferably 390°C or higher, preferably 395°C or higher, preferably 400°C or higher, more preferably 410°C or higher. The pyrolysis temperature can range from 360 to 550°C, more preferably 390 to 450°C.

[0085]

[0104] The molten partially pyrolyzed plastic material exits the heating zone 4 at pyrolysis temperatures and passes into a separation vessel 12 via a separation vessel inlet 14 .

[0086]

[0105] In the separator vessel 12, the incoming cracked gas and liquid separate. The gas rises and exits the partial condenser 5, and the liquid falls to the bottom of the separator vessel 12.

[0087]

[0106] A recycle loop 26 is provided for removing the liquid, partially pyrolyzed plastic material collected in the separation vessel 12 by means of a pump 27. The removed liquid is reheated to pyrolysis temperatures by a heat exchanger 28 and then returned to the separation vessel 12, together with fresh feed in the illustrated case. This recycle loop 26 increases the residence time of the long-chain hydrocarbons at the pyrolysis temperature so that they are subjected to further pyrolysis and broken down into shorter-chain hydrocarbons, finally exiting via the partial condenser 5.

[0088]

[0107] The recycle loop 26 provides for reheating and reintroducing heat into the separation vessel 12 so that the separation vessel 12 remains at pyrolysis temperatures. Heat is carried to the separation vessel 12 by the incoming reheated material stream supplied by the recycle loop 26.

[0089]

[0108] In the preferred embodiment shown, the separation vessel 12 is unheated, and the term "unheated" means that the separation vessel 12 is not heated by any source other than heat carried by incoming heated material, such as heated material entering the interior volume of the separation device from a heating device such as heating device 11 or another heating device that may be provided in a recycle or return loop.

[0090]

[0109] It has been found useful to avoid providing heating means on or within the separation vessel, as can be found in some prior attempts. This can help reduce char formation in the separation vessel 12 and reduce or avoid the need for special agitation means. For example, prior attempts have found that internal heaters, such as heating coils, can cause charring of the pyrolysis material on the surfaces of the heating elements. This charring can represent a loss of product and can collect on the heating elements, requiring downtime for cleaning and maintenance. The same can be true for cracking reactor-type vessels that heat the vessel walls to bring or maintain the processed material at pyrolysis temperatures. Charring can occur on the interior surfaces of the cracking reactor walls, requiring complex mixing, cleaning, and downtime. Nevertheless, the use of direct heating of the separator vessel, such as via a jacket or internal heat exchangers or heating coils, is not precluded from use in some embodiments or aspects of the present invention and may be used to provide all or a portion of the heat requirements of the pyrolysis zone(s).

[0091]

[0110] In the preferred embodiment shown, separation vessel 12 is not provided with an agitator, such as a stirrer or auger. Without wishing to be bound by theory, it is believed that including an auger or similar agitation device to agitate the liquid in the separator vessel may be disadvantageous because it introduces complexity, creates surface areas for carbon / char buildup, reduces efficiency and requires maintenance, and may disrupt the flow pattern imparted by the injection or material. However, an agitator in separation vessel 12 may optionally be provided or is not excluded from some embodiments and aspects, as it may be useful to improve mixing within separation vessel 12.

[0092]

[0111] The combination of separation vessel 12, partial condenser 5 and reboiler 16 is more clearly illustrated in FIG.

[0093]

[0112] Upon entering separation vessel 12 via inlet 14, the plastic material is at its pyrolysis temperature and is therefore undergoing pyrolysis. Cracking of the plastic material results in the production of a wide range of substances with a wide range of boiling points. The plastic material exiting heating device 11 and entering separation vessel 12 via inlet 14 includes at least both gaseous and liquid components, and the liquid component includes, and may consist essentially of, at least partially cracked plastic material. The liquid component may also include molten, uncracked plastic material. The plastic material exiting heating device 11 and entering separation vessel 12 via inlet 14 may further include silt and other solid detritus, such as sand, aluminum, or other metal particles.

[0094]

[0113] The illustrated separation vessel 12 is elongated and arranged substantially vertically. Non-vertical arrangements, such as inclined or horizontal, are also contemplated. The pyrolyzed gaseous material rises in the separation vessel 12, while the liquid (partially) pyrolyzed material falls under gravity. In this manner, the gaseous and liquid materials separate and separate in the separation vessel 12.

[0095]

[0114] The gaseous hydrocarbon material rising in separation vessel 12 is discharged through upper outlet 132 and passes via line 6 to partial condenser 5. Partial condenser 5 is remote from and positioned downstream of separation vessel 12. Partial condenser 5 is in fluid communication with separation vessel 12 via line 6. Line 6 is a gas line that transports gas to the partial condenser. Liquid does not pass through line 6.

[0096]

[0115] Partial condenser 5 is positioned and / or configured to remove a heavy fraction (a lower, higher point fraction) from the exiting gas before the exiting gas is sent further to the full distillation or condenser section of the apparatus and process. In partial condenser 5, the gas is cooled as discussed below. As the gas is cooled, the heavier fraction can condense and be collected, while the lighter fraction remains in gaseous form and is sent via line to reboiler 16.

[0097]

[0116] The partial condenser 5 is preferably provided with a packed column 28 having (optional) random packing such as rings, e.g., Raschig rings, which increases the contact surface area between the gas and the liquid being condensed in the partial condenser. As is known in condensation processes, this packed column 28 can aid in effective condensation by providing a large solid surface area for the gas to condense upon.

[0098]

[0117] Partial condenser 5 is also preferably provided with a temperature controlled cooling element 29, such as a cooling coil supplied with a temperature regulated cooling medium. The temperature of cooling element 29 is controlled to cause condensation of long chain hydrocarbons (e.g., longer than C22), and this condensed material falls under gravity into a lower portion of partial condenser 5. Cooling element 29 is preferably downstream of packed column 28.

[0099]

[0118] Alternatively, or additionally, selective condensation may be achieved by a cooling jacket (not shown) acting as a cooling element, or the partial condenser may be an external (full reflux) condenser.

[0100]

[0119] The gases (C1 to C20 / C22, possibly up to C35) that do not condense in the packed column 28 or the cooling element 29 are discharged via the upper outlet of the partial condenser and pass via line 30 to a downstream distillation unit of the type commonly known for distillation applications in the petrochemical sector, for example used for the distillation of crude oil or mineral oil fractions.

[0101]

[0120] The downstream distillation section can be designed according to industry standards known to those skilled in the art. The gas can be fractionated into a gaseous fraction and a liquid fraction. In the distillation unit, the liquid fraction can be stripped as a middle distillate, and the gaseous fraction can be stripped as a light-boiling material. Hydrocarbon products from the distillation unit can include butane, propane, kerosene, diesel, fuel oil; light distillates such as LPG, gasoline, naphtha, or mixtures thereof; middle distillates such as kerosene, jet fuel, diesel, or mixtures thereof; heavy distillates and residues such as fuel oil, lubricating oil, paraffin, wax, asphalt, or mixtures thereof. The hydrocarbon products can be saturated, unsaturated, linear, cyclic, or aromatic. Additional products can include non-condensable gases containing methane, ethane, ethene, and / or other small molecules. The products can be a source of raw material for a steam cracker for the production of plastics.

[0102]

[0121] Hydrocarbons that condense in the partial condenser 5 (eg, containing C22 and higher chains, and possibly small amounts of carbon chains below C22) collect as liquid 31 at the bottom of the partial condenser 5 .

[0103]

[0122] The liquid level in the bottom of the partial condenser is controlled by one or more level control sensors and can be discharged batchwise or continuously. Level control of the partial condenser 5 can be achieved continuously by a flow control valve.

[0104]

[0123] The condensed liquid 31 from the partial condenser preferably exits through a lower outlet 32 ​​of the partial condenser and is sent to the reboiler 16 via a line 33 controlled by an optional valve 34. Valve 34 can be either an on-off valve or a control valve.

[0105]

[0124] The condensed liquid 31 collects in the reboiler 16, where it is reheated by a heater 13, preferably an internal heating element or an internal heat exchanger. The reboiler heater 13 can be electrically heated by thermal oil or other type of heating medium. The condensed liquid in the reboiler 16 is heated to a temperature higher than that of the partial condenser. An external heating element or external heat exchanger is also contemplated.

[0106]

[0125] Light hydrocarbon fractions that may unavoidably be carried along with the condensed liquid from the partial condenser can be vaporized or boiled off in this manner and sent to the distillation apparatus via the upper outlet 15 of the reheater vessel. These light hydrocarbon fractions can then be included in the distillation product. This can improve product yields compared to systems or processes in which the partially condensed material is returned directly to the thermal cracking zone. This is also considered preferable to returning the light hydrocarbons to the thermal cracking zone, where they are cyclically heated, re-vaporized, and then re-condensed, potentially subjecting them to further cracking or creating relatively unwanted heat release.

[0107]

[0126] A reboiler 16 is preferably configured as a component of the distillation section and is connected in gas fluid communication through the upper outlet 15 of the reheater vessel.

[0108]

[0127] Liquid 35 collected in the reboiler and not vaporized for distillation through reheater vessel upper outlet 15 is pumped back to separator vessel 12 via line 9 using pump 10 and optionally further heated before entering separator vessel 12. In this manner, the liquid can be further pyrolyzed into more useful lighter products than those condensed in partial condenser 5. For example, liquid can be returned to separator vessel 12 and / or the thermal cracking zone and cracked until they are reduced to chain lengths of C20-C22 or less. Thus, product yields can be improved and / or the ratio of light to heavy products can be more tailored to customer requirements.

[0109]

[0128] Alternatively, the liquid collected in the reboiler and not vaporized through the upper outlet 15 of the reheater vessel for distillation can be collected as a useful product, for example, this product can be paraffin, and can be transported via valve 21 to a collection vessel.

[0110]

[0129] The partial condenser coil 29 typically operates at a temperature between 220° C. and 380° C., and the reboiler typically operates at a temperature between 340° C. and 400° C. Both of these temperatures are below typical crack reactor operating temperatures of less than 390° C. and 450° C.

[0111]

[0130] The liquid pyrolyzed material exiting separator vessel 12 is continuously circulated, preferably by an external pump 27. As the liquid is circulated, it can be reheated by heat exchanger 28 to pyrolysis temperatures for further cracking.

[0112]

[0131] Preferably, a distillation column (not shown) is provided above the upper outlet 15 of the reheater vessel. The distillation column may have a section designed as a packed column, and optionally, intermediate trays may be provided in this packing-containing section, or preferably above this section, on which the liquid fraction (diesel product or HHC) can be collected and discharged. The HHC, e.g., diesel product, discharged from the distillation unit is preferably cooled by a heat exchanger, and part of this cooled diesel product can be recycled to the distillation unit via a recycle stream line to set optimal temperature conditions.

[0113]

[0132] Settings that may result in low range product compositions include: Partial condenser outlet temperature of approximately 290°C Reboiler (liquid) temperature of approximately 360°C The outlet temperature of the upper distillation column is approximately 80°C. LHC condenser temperature of condensed LHC liquid of about 42°C HHC final boiling point: 430℃

[0114]

[0133] Potential configurations that result in mid-range product compositions include: Partial condenser outlet temperature of approximately 320°C Reboiler (liquid) temperature of approximately 380°C Outlet temperature of the upper distillation column is approximately 100°C LHC condenser temperature of condensed LHC liquid of about 42°C HHC final boiling point: 450℃

[0115]

[0134] Configurations that may result in high range product compositions include: Partial condenser outlet temperature: approx. 330°C Reboiler (liquid) temperature of approximately 380°C The outlet temperature of the upper distillation column is approximately 120°C. LHC condenser temperature of condensed LHC liquid of about 55°C HHC final boiling point: 550℃

[0116]

[0135]

[0136] 3-9, more detailed views of a separation vessel 12 usable in the system of FIGS. 1 and 2 are provided.

[0117]

[0137] The separation vessel 12 in a plastics to chemicals (PTC) facility typically has multiple functions, which may include any, some, or all of the following:

[0118]

[0138] The separation vessel can function to aid in the separation of gas, liquid, and solid particulate phases present in the inlet stream of partially cracked plastic material. As discussed, the plastic material entering the separation vessel from heating device 11 is at a temperature where the plastic material is undergoing pyrolysis but not yet completely pyrolyzed. Thus, the plastic material exiting heating device 11 and entering separation vessel 12 via inlet 14 contains at least gaseous and (partially cracked) liquid components, which are separated for separate further processing. The incoming material flow may also contain solid particulate material. A significant portion of the solid particulates result from the pyrolysis reaction and the pyrolysis reaction's production of charcoal or coke particles common in pyrolysis. Other particulates may be present due to impurities in the initial plastic feed stream to the process, such as metal particles and other detritus.

[0119]

[0139] In the separator vessel, the gaseous material separates from the liquid and solid material by gravity and travels upward toward the exit point. The liquid and solid phases travel downward and collect in the separator vessel 12.

[0120]

[0140] According to one aspect of the present invention, separation efficiency and quality can be achieved by implementing various velocity patterns for the fluid flow in separator 12.

[0121]

[0141] Separator vessel 12 can function to provide residence time for cracking the plastic material in a pyrolysis zone, i.e., a zone where the temperature is high enough to cause pyrolysis. The plastic material can remain in separator 12 for a short period of time and be cracked in that manner, and the liquid plastic material can also be removed, reheated, and returned to separator vessel 12 for separation and / or further pyrolysis.

[0122]

[0142] The separation vessel 12 can function to mix fresh inflow liquid plastic material from the heater 11 with recycled partially cracked plastic material from a heater external to the separation vessel 12 and / or a reboiler, etc.

[0123]

[0143] Separator vessel 12 can function to control the characteristics and quality of the product stream through control of temperature, residence time, containment volume and / or pressure.

[0124]

[0144] The separator vessel 12 may function to separate solid particulates (e.g., coke, char particles, or other detritus) from the bulk of the pyrolysis liquid. This may be achieved by either or both of an advantageous separator vessel 12 configuration and / or a flow pattern of the material flow in the separator vessel 12. The solid particles may be removed as bitumen. Advantageously, the separator 12 may function to allow removal of the solid particles, coke, char, bitumen, and detritus as part of a continuous pyrolysis process. That is, the bitumen, including the solid particles, coke, char, and detritus, may be removable from the separator vessel while pyrolysis continues in the separator vessel 12.

[0125]

[0145] The separator vessel 12 serves as a (temporary) holding vessel for the liquid (partially) cracked liquid plastic material, and thus allows maintaining a volume of liquid (partially) cracked liquid plastic material in the system, which can advantageously facilitate (re)start-up operations, for example, since the system pumps can be primed from this liquid volume at start-up and / or provide NPSH (Net Positive Suction Head) for pumps operating on liquid in the separator vessel 12.

[0126]

[0146] Referring to Figures 3-9, the separator vessel is shown in greater detail.

[0127]

[0147] The separator vessel 12 shown has several injection and discharge points.

[0128]

[0148] A fresh feed injection point 121 is provided in the side wall of the separator 12 to receive a fresh feed of plastic material exiting the heating device 11 and entering the separation vessel 12 through the inlet 14 of the fresh feed injection point 121.

[0129]

[0149] The separator has a return feed injection point 122 in the side wall through which the reheated partially cracked plastic material can be returned after reheating in the recycle reheat loop 26.

[0130]

[0150] A reboiler return injection point 124 is preferably provided at the top of separator vessel 12 for injecting liquid 35 (e.g., paraffins) collected in reboiler 16 and pumped back to separator vessel 12 via line 9. The liquid 35 collected in reboiler 16 is preferably composed of paraffins and / or long chain hydrocarbons having a boiling point above about 400°C.

[0131]

[0151] The reboiler return injection point 124 is preferably positioned above the liquid level in the separator vessel 12, most preferably at the top of the separator vessel 12. This positioning can help prevent the reboiler return injection point 124 from becoming contaminated with carbon / charcoal, as would occur if the reboiler return injection point 124 were below the liquid level in the separator vessel 12.

[0132]

[0152] The injection of reboiler liquid 35 into separator vessel 12 via line 9 is preferably semi-continuous, and most preferably continuous. This injection is believed to advantageously provide a stable process for pyrolysis in separator vessel 12 with predictable and stable heat distribution and / or predictable and stable flow streams in separator vessel 12. This is believed to be advantageous compared to batch delivery.

[0133]

[0153] Liquid 35 returned from reboiler 16 to separator vessel 12 can be further cracked in separator vessel 12 to form more desirable shorter chain products.

[0134]

[0154] A nitrogen injection point 125 is provided above the pyrolysis reaction for injection of a nitrogen blanket. The nitrogen injection point 125 is preferably positioned at the top of the separator vessel 12. A (semi-)continuous flow of nitrogen gas is preferably supplied to the upper zone of the separator vessel 12 via a nitrogen injection point nozzle. The flow rate can range from 1 to 20 liters per hour, more preferably from 2 to 10 liters per hour. The nitrogen gas supply can help maintain the pyrolysis system, separator vessel 12, at atmospheric pressure or preferably higher. Overpressure (above ambient pressure) can help eliminate oxygen ingress, thus reducing the risk of unwanted air entrainment, which can adversely affect product quality, particularly that of the HHC product.

[0135]

[0155] An internal, preferably substantially central, liquid outlet 128 is provided in the hollow body of the separator vessel, through which the liquid, partially cracked plastic material can be removed (e.g., under the influence of a pump) and sent to the reheat loop 26.

[0136]

[0156] A side liquid outlet 127 is provided through which the partially cracked plastic material liquid can be substantially removed from the peripheral region of the separator vessel (e.g., under the influence of a pump) and sent to the reheat loop 26.

[0137]

[0157] A carbon outlet 124 is provided at the base of separator 12 for discharging carbon-containing bitumen or other solids that settle to the bottom of separator 12 .

[0138]

[0158] A pressure equalizer line 123 is provided. The pressure equalizer line can assist in pressure equalization during bitumen / carbon discharge from the base of the separator vessel 12.

[0139]

[0159] Bitumen recirculation nozzles 130, 131 may also be provided. Bitumen or high solids material at the base of separator vessel 12 may be recirculated to reduce or prevent gelling, clumping, coagulation, etc. in dense materials. This recirculation may help prevent plugging of carbon outlet 129.

[0140]

[0160] A gas outlet 132 is provided at the top of the illustrated separator vessel 12, through which the (partially) cracked gaseous material produced during the pyrolysis reaction can be sent via line 6 to partial condenser 5 and then optionally sent for further processing in the form of distillation, use as fuel and / or further processing.

[0141]

[0161] In general, it is advantageous for all inlets and outlets to the separation vessel 12 to be flush with the interior surface of the separator vessel 12, i.e., not protruding substantially into the vessel, if possible. This can help reduce or prevent fouling and / or disruption of flow patterns in the separation vessel.

[0142]

[0162] For use in pyrolysis, a fresh feed stream is delivered from heating device 11 to separator vessel 12 at fresh feed injection point 121 via separator vessel inlet 14. The incoming fresh feed contains gas and liquid phases resulting from the melting and cracking that occurred in heating device 11. Upon entering separator vessel 12, the incoming cracked gas and liquid separate. The gas rises to gas outlet 132 and exits via line 6 to partial condenser 5, with the liquid (with any entrained solid particles) accumulating in separator vessel 12 and the solid particles sinking to the bottom through the liquid phase. Separator vessel 12 is filled to a predetermined level with the liquid phase in its lower portion, and the gas phase separates upward toward the upper portion of the vessel where the gas phase is primarily present.

[0143]

[0163] In the illustrated embodiment, a fresh feed of gas / liquid mixture is shown injected tangentially into separator vessel 12. The gas and liquid phases then separate into upper and lower phases, respectively, in the interior volume of separator vessel 12.

[0144]

[0164] The tangential introduction or injection of fresh feed can, at least in part, impart a vortex or cyclonic flow pattern to the incoming gas / liquid stream, which can aid in efficient phase separation of the stream by centrifugal force pushing the denser liquid to the periphery and causing the gas to rise upward.

[0145]

[0165] The liquid and entrained solids collect at the bottom of separator vessel 12. The collected liquid is not yet sufficiently cracked for all the desired product properties and is still too heavy to distill. Therefore, in the plastics-to-chemicals conversion process, the liquid is subjected to additional residence time under pyrolysis conditions to further crack the polymer chains.

[0146]

[0166] As discussed hereinabove, it has been found useful to avoid providing heating means on or within the separation vessel 12, for example, heating the walls of the crack reactor or providing heating elements or heat exchangers in the crack reactor, as can be found in some prior attempts.

[0147]

[0167] To introduce heat into separator vessel 12 and thus maintain the pyrolysis temperature of separator vessel 12, liquid collected in the lower portion of separator vessel 12 is removed from separator vessel 12 and sent through recycle heating loop 26, and the liquid partially pyrolyzed plastic material is reheated to the pyrolysis temperature by heat exchanger 28 and then returned to separator vessel 12. In some embodiments, the reheated plastic material can be combined with fresh feed prior to injection into separator vessel 12. In the embodiment illustrated in FIGS. 3-10, a recycle stream, return feed injection point 122, separate from fresh feed injection point 121, is provided in the sidewall of separator vessel 12 through which the reheated partially cracked plastic material is returned after reheating in recycle reheat loop 26. The return feed stream carries heat to separator vessel 12, maintaining pyrolysis conditions in separator vessel 12, while also providing additional residence time for the plastic material to be further cracked until the resulting shorter chain hydrocarbons can be distilled and processed into desired products.

[0148]

[0168] The liquid level in separator vessel 12 can be controlled, for example, by balancing the input of fresh feed and the output of gaseous cracked material. The rate of output of gaseous material can be controlled primarily through the rate of pyrolysis, i.e., by controlling the temperature in separator vessel 12. This temperature can be controlled by the rate of circulation of liquid through recycle reheat loop 26 and / or the temperature of the heater in recycle reheat loop 26.

[0149]

[0169] The equilibrium liquid level can also be controlled by controlling the rate of fresh feed input by increasing or decreasing the feed of fresh molten plastic from heater 11. The equilibrium liquid level can also be controlled by controlling the rate of coal removal or coal purge from separator vessel 12 by increasing or decreasing the removal of coal-containing material from the base of separator vessel 12.

[0150]

[0170] The pressure in separator vessel 12 is preferably maintained at greater than atmospheric pressure, preferably slightly greater than atmospheric pressure, for example, in the range of 50-100 mbarg. The pressure in separator vessel 12 can be controlled to affect product yield, and it is contemplated that separator vessel 12 can be operated at higher or subatmospheric pressures.

[0151]

[0171] Operating the separation vessel at higher pressures, such as above 100 mbarg, preferably above 200 mbarg, and more preferably above 300 mbarg, can help produce lighter products with lower end points or a greater fraction of lighter products. Even higher pressures, above 5 barg, may be used. Without wishing to be bound by theory, it is believed that higher pressures inhibit the vaporization of hydrocarbon chains, with longer chain hydrocarbons being more affected by this than shorter chain hydrocarbons. Hydrocarbons, particularly longer chain hydrocarbons, are less likely to vaporize and remain in the thermal cracking zone where they are further cracked into lower boiling point hydrocarbons.

[0152]

[0172] Operating the separation vessel at lower pressures, for example, below atmospheric pressure, for example, below 0 mbarg, preferably below 10 mbarg, more preferably below 30 mbarg, more preferably below 50 mbarg, can help increase the fraction of high boiling materials such as paraffins. Even lower pressures (vacuum reactors) above 0 bar (absolute) can also be used. Without wishing to be bound by theory, it is believed that at lower pressures, long chain hydrocarbons vaporize more easily and exit the pyrolysis zone before they are further cracked to lower boiling materials.

[0153]

[0173] Temperature and residence time within separator vessel 12 are interrelated. By balancing these two parameters, a desired liquid volume can be achieved in separator vessel 12. For example, higher temperatures can increase the rate of cracking and gasification, reducing the residence time of the material in the system.

[0154]

[0174] The temperature of the liquid in the separator vessel 12 is controlled to be at the pyrolysis temperature. Preferably, the temperature of the liquid in the separator vessel is controlled to be about 360°C or higher, more preferably about 390°C or higher, preferably 395°C or higher, preferably 400°C or higher, more preferably 410°C or higher. The pyrolysis temperature can range from 360 to 550°C, more preferably 390 to 450°C, more preferably about 400°C to about 450°C. The higher the temperature, the faster the cracking reaction will occur.

[0155]

[0175] The residence time in the pyrolysis zone of the apparatus and operation is preferably from about 10 minutes to about 12 hours, more preferably from about 20 minutes to about 6 hours, and more preferably from about 30 minutes to about 3 hours. Residence time is a measure of the time a volume of material resides in the pyrolysis zone. The residence time for a system can be calculated as volume (m3) / flow rate (m3 / s). Residence time can be reported as the mean residence time or mean transit time, i.e., the average residence time of all material exiting the control volume at time t.

[0156]

[0176] The temperature and rate of production can be varied in the pyrolysis process and adjusted depending on the type of raw plastic. This allows the process to be adapted to different plastic types, especially those with various cracking temperatures. The operation can be adjusted to crack homogeneous feedstocks or heterogeneous feedstocks having two or more plastic types.

[0157]

[0177] As discussed, separator vessel 12 is provided with a fresh feed injection point 121 and a return feed injection point 122. It has been found that the fresh feed injection point 121 and the return feed injection point can significantly affect the flow behavior of the fluid within separator vessel 12.

[0158]

[0178] One or preferably both of the fresh feed injection point 121 or the return feed injection point 122 may be positioned to inject the gas / liquid feed into the separator vessel 12 substantially tangentially, preferably along or above the interior wall of the separation vessel 12, preferably in a circumferential direction. The injection points 121, 122 preferably inject the feed into the separation vessel below the level of the liquid in the separation vessel 12 to set up a rotational, vortex, or cyclonic flow pattern in the liquid. Alternatively, one or more of the injection points 121, 122 may be positioned to inject the feed above the level of the liquid in the separation vessel 12, although this is less preferred.

[0159]

[0179] The discussed introduction of collected liquid into a gas / liquid zone below can provide a cyclone effect, which advantageously does not require an auger or similar agitation device to force the collected liquid out and into the cyclone rotation.

[0160]

[0180] This cyclone effect can advantageously improve one or more of settling of solids, particularly dense particles (denser than the liquid), within separation vessel 12, distribution of heat from the incoming feed to materials already in separation vessel 12, and gas and liquid separation, and can form a central zone in the collected liquid having a relatively low concentration of solid particles, such as carbon particles, from which liquid can be removed by internal, preferably substantially central, liquid outlet 128 and sent to reheat loop 26. This cyclone effect can help reduce or prevent buildup of blockages in reheat loop 26, pump 27, heat exchanger 28, and / or return feed injection point 122.

[0161]

[0181] The strength of the vortex, cyclone effect can be controlled by controlling or varying the inlet velocities at the fresh feed injection point 121 and / or the return feed injection point 122 (e.g., by changing the pump capacity, higher recirculation flow, or larger mass injection), and by the ratio or relative inlet velocities of the two inlet velocities.

[0162]

[0182] The inlet velocity can be increased by narrowing the inlet nozzle at the injection point, for example, the fresh feed inlet nozzle can be reduced in inner diameter from about 8 cm to about 6 cm, and the return feed inlet nozzle can be reduced in inner diameter from about 15 cm to about 8 cm. Nozzle narrowing is illustrated in Figure 9.

[0163]

[0183] The velocity at the fresh feed injection point 121 and / or the return feed injection point 122 may also increase due to the production of pyrolysis gases in the heater 11 and reheat loop 26, both of which contain pyrolysis temperature zones. As the gases expand into the relatively low pressure separation vessel 12, they accelerate to high inlet velocities, which can help create a cyclone effect.

[0164]

[0184] The cyclone flow effect can also be controlled by the ratio of flow rates and / or velocities between the fresh feed injection point 121 and the return feed injection point 122. Preferably, the ratio of flow rates (liters per second) between the fresh feed injection point 121 and the return feed injection point 122 is preferably about 1:1 to 1:25, more preferably 1:20, more preferably 1:15, and most preferably 1:8. The operating ratio can be selected (e.g., preferably about 1:1 to 1:25, more preferably 1:20, more preferably 1:15, and most preferably 1:8) and can be adjusted during operation, for example, by reducing the frequency control of the associated pumps. The feed ratio can be adjusted during operation to increase or decrease the temperature in the separator vessel 12 to slow or accelerate pyrolysis.

[0165]

[0185] Additional or alternative injection nozzles may be provided at various circumferential locations that can be optimized to achieve a stable cyclonic effect.

[0166]

[0186] The cyclonic flow effect can also be controlled by adjusting the surface roughness of the inner walls of the separator vessel 12. Lower surface roughness reduces friction between the walls and the liquid, thereby affecting the velocity of the liquid within the vessel.

[0167]

[0187] While previous attempts have been made to inject hot plastic melts into pyrolysis operations, the present invention advantageously achieves improved separation, heat distribution and / or reheating of liquid pyrolysis material by injecting a gas / liquid mixture into the reactor vessel at high velocities and / or defined substantially tangential angles and different ratios between injection nozzles, thereby creating a vortex in the liquid.

[0168]

[0188] Other prior attempts to inject hot plastic melt into pyrolysis operations have involved premixing the fresh and return feeds prior to entry into the pyrolysis vessel. Without being bound by theory, the present invention is advantageous because it allows the fresh feed to be introduced into the separation vessel more efficiently.

[0169]

[0189] It has been found that providing pyrolysis prior to separation vessel 12, for example, heater 11 achieving pyrolysis temperatures prior to injection into the separation vessel, can generate a large amount of gaseous material. It is believed that a more efficient process can be obtained by releasing this gaseous material into separator vessel 12 prior to mixing with the return feed. It is believed that this process can help reduce or prevent further or excessive cracking of the already gaseous material.

[0170]

[0190] Furthermore, without wishing to be bound by theory, it is believed that injecting fresh feed into separator vessel 12 separately from the recycled, reheated stream may improve the efficiency and resilience of the system, particularly the pumps in recycle line 26. This is believed to be because pressure peaks or pressure pulses that may occur in the fresh stream feed due to the high gas content and high pressure in the fresh feed are less likely to be transmitted to the pumps in recycle stream 26. Instead, the relatively large volume of separator vessel 12 can absorb or dissipate pressure peaks associated with injecting fresh feed. This relatively large volume may help improve the efficiency and reduce maintenance requirements for the pumps in recycle loop 26.

[0171]

[0191] Pyrolysis (thermal decomposition of materials at high temperatures in an inert atmosphere) cracking hydrocarbons will result in the formation of coke particles in the plastic material stream. Coke particles form in all pyrolysis zones of the process, including heater 11, separator vessel 12, and recycle heater loop 26. Solid coke particles will tend to accumulate at the bottom of separator vessel 12.

[0172]

[0192] In addition to solid coke particles, other particulates may be present due to impurities in the initial plastic feed stream to the process, such as metal particles and other detritus. The feedstock may contain inorganic materials, such as sand, glass, metal, etc., preferably less than 10 wt. %, more preferably less than 5 wt. % inorganic matter.

[0173]

[0193] It is advantageous to avoid or prevent excessive buildup and resulting blockage of the separation vessel 12 and / or to efficiently remove solid particles to avoid product contamination.

[0174]

[0194] As discussed in connection with the tangential introduction of the fresh feed stream at fresh feed injection point 121 and the tangential introduction of the recycled reheater stream at return feed injection point 122, the injections affect the flow behavior within separator vessel 12. Tangential introduction through one, both, or more of such nozzles can cause the fluid within the crack reactor vessel to form a cyclone. This cyclone effect can advantageously improve the settling of solids within separator vessel 12, similar to a centrifuge. This cyclone effect advantageously allows the (centrifuged) solids to remain adjacent to the interior wall, sink, and be less susceptible to being sucked in by a pump than lighter fluids.

[0175]

[0195] Referring to FIG. 10, the lower conical section of the separator vessel 12 is shown, which reaches its lowest point at the carbon discharge point 129 .

[0176]

[0196] Solid particles present in the pyrolysis liquid in the separation vessel 12 will tend to fall to the bottom of the separation vessel 12 and settle and accumulate in the illustrated lower conical section 133 where the fluid flow is lower energy or slower and more gentle.

[0177]

[0197] Once the solids reach the bottom of separator vessel 12, they accumulate. The conical shape of the reactor bottom can help direct the settling solids to the carbon discharge section.

[0178]

[0198] The settling of solid particles by the lower conical section is particularly effective when combined with the cyclone effect which pushes the solids against the inner wall of the separation vessel 12 .

[0179]

[0199] Without being bound by theory, it is believed that the angle of the cone slope is important to achieve effective settling of the solids and avoid blockage of the lower portion of the separator vessel 12. Through research, it has been found that the angle of slope of the inner surface of the conical reactor should be properly balanced so that certain types of solid particles produced during pyrolysis do not adhere to or build up on the inner walls of the separator vessel 12, yet still allow the solids to proceed to the carbon outlet 129. A steeper angle can also result in excessive vessel height, which can limit the volume in the lower portion of the vessel.

[0180]

[0200] Without being bound by theory, it is believed that efficient pyrolysis can be achieved when separator vessel 12 is provided with a conical lower section 133 having an internal opening angle α of the conical lower section of separator vessel 12 of from about 30° to about 70°, more preferably from about 50° to about 70°, more preferably from about 55° to about 65°, and most preferably about 60°.

[0181]

[0201] Furthermore, without being bound by theory, it is believed that solid particle separation can be improved by limiting the surface roughness of the inner surface(s) of separation vessel 12, particularly the conical lower portion 133 of separation vessel 12. This limitation can help to reduce buildup of blockages and prevent buildup of fouling and carbon solids, as well as ensure effective and rapid settling.

[0182]

[0202] Efficient pyrolysis can be achieved when separator vessel 12 is provided with a surface roughness of Ra 20 or less, preferably Ra 18 or less, more preferably Ra 15 or less, more preferably Ra 12 or less, and most preferably Ra 6 or less for one or more of its inner surfaces. Preferably, the inner surface of the conical lower section has such limited surface roughness.

[0183]

[0203] Surface roughness is measured as a roughness average (Ra) having units of micrometers. Methods for measuring surface roughness are known to skilled workers. As an example, surface roughness can be measured using a perthometer with a diamond probe that records the uneven height of the surface. Methods for adjusting the surface roughness of a given material are also known to skilled workers and can include, but are not limited to, deburring, sawing, planing, shaping, drilling, or (chemical) milling.

[0184]

[0204] In previous independent attempts at implementing plastics-to-chemicals plants, the vessels that aid in the separation of pyrolysis liquids and gases were equipped with oval heads rather than conical bottoms, an alternative that caused the bottoms to fill with contaminants, ultimately causing the reactors to fill and plug.

[0185]

[0205] In a further previous independent attempt at implementing a plastics-to-chemicals plant, a vessel to aid in the separation of pyrolysis liquid was equipped with an inverted cone at the bottom of the vessel. The purpose of the inverted cone was to stop the flow at the bottom of the vessel, provide recirculation, and improve the settling of solid particles. However, research has shown that clogging occurs due to the inverted cone. For example, the peripheral openings around the inverted cone can become blocked by charcoal, and charcoal can build up in the inverted cone.

[0186]

[0206] Previous techniques have not been able to achieve (semi-)continuous discharge of solid particles such as carbon, or ongoing discharge of particles such as carbon. Previous attempts at pyrolysis required shutting down pyrolysis for a given pyrolysis zone while removing the (dry) carbon, or residual charcoal, by grinding. The conical shape of the lower section 133 and cyclonic fluid flow in the separator vessel 12 of the present invention can help achieve efficient carbon removal without or with reduced pyrolysis shutdown requirements. In particular, the combination of the conical shape of the lower section 133 and cyclonic fluid flow is effective. Continuous residual char removal can be advantageous.

[0187]

[0207] 11, there is shown a schematic diagram of a separation vessel 12 provided with a recycle reheat loop 26. The recycle reheat loop 26 is the source of thermal energy to the separator vessel 12, and preferably is the primary source of thermal energy to the separation vessel 12.

[0188]

[0208] Liquid 140 in the lower portion of separation vessel 12, including, for example, molten plastics and partially pyrolyzed hydrocarbons, is pumped by pump 27 to heat exchanger 28, preferably a shell-in-tube heat exchanger. Heat exchanger 28 (re)heats the liquid to a temperature higher than the temperature of the liquid in separation vessel 12, for example, from about 410 to about 550°C, more preferably from about 410 to about 500°C, and even more preferably from about 410 to about 450°C.

[0189]

[0209] At these temperatures, pyrolysis occurs and the pumped liquid stream generates pyrolyzed gases, which constitute part of the gas stream. To reduce cavitation effects in the pump 27, the pump is preferably upstream of the heat exchanger 28, so that the pump 27 is primarily in liquid phase.

[0190]

[0210] The (re)heated fluid carries the thermal energy back to the separator vessel 12, heating it from the inside.

[0191]

[0211] The fluid in the heat exchanger 28 preferably has a minimum velocity to keep solid particulates in suspension (preventing settling) and reduce fouling of the heat exchanger surfaces with carbon or charcoal. The minimum velocity is preferably about 1 m / sec, more preferably about 2 m / sec, at the inlet to the heat exchanger 28. The velocity at the outlet of the heat exchanger 28 can be higher due to gas formation, which increases volume and pressure.

[0192]

[0212] The liquid gas mixture is then directed by recycle reheat loop 26 and injected tangentially into the crack reactor at high velocities (e.g., about 5 m / s, more preferably about 8 m / s, and most preferably about 10 m / s). Tangential injection can advantageously help to impart a vortex or cyclonic flow pattern to the fluid in separator vessel 12. The liquid gas mixture is injected below liquid level 141. This injection can help to create a desirable flow pattern in the gas / liquid zone of separator vessel 12 and / or reduce or prevent plugging of the injection point.

[0193]

[0213] Liquid 140 in the lower portion of separator vessel 12 is withdrawn from separator vessel 12 through one or more outlets.

[0194]

[0214] In the illustrated embodiment, two outlets are shown: an internal, preferably substantially central, liquid outlet 128 in the hollow body of the separator vessel, and a side liquid outlet 127. The liquid outlets 128, 127 can be used individually or together.

[0195]

[0215] 12-13, internal liquid outlet 128 is radially centrally located in separator vessel 12, although other or substantially radially central locations may be employed. The opening of internal liquid outlet 128 is positioned below liquid level 141 in separator vessel 12 to allow liquid to be withdrawn. Substantially centralizing the opening of internal liquid outlet 128 can be advantageous because the cyclone fluid flow in separator vessel 12 has a relatively low velocity in the radially central portion compared to the radially outer fluid flow, tending to centrifuge solid particles to the periphery. Thus, liquid with a relatively low solid particle content can be withdrawn at the opening of internal liquid outlet 128, as illustrated by arrow 145 in FIGS. 13 and 14.

[0196]

[0216] 13, the depicted key shows the liquid level 551, the liquid flow near the inner surface with lower tangential velocity 552, the solid particles (carbon particles) in the liquid 553, the direction of liquid flow 554, the liquid proceeding to the pump inlet 555, the high velocity liquid compartment 556 in the radially outer part of the vessel 12, and the gas bubbles 556. At this location, only some or a low concentration of gas bubbles 556 may be present.

[0197]

[0217] The opening of the internal liquid outlet 128 is preferably located above the level of the conical bottom section 133 or settling zone to reduce entrapment of settled solid particles in the conical bottom section 133 .

[0198]

[0218] The opening of the internal liquid outlet 128 is shown as having a vertically oriented outlet 146 including a lower opening 147 and an upper opening 148, with a sidewall extending between the openings. The lower portion of the outlet 146 has a cylindrical shape (with a circular or other cross section), while the upper portion leading to the upper opening 148 has a frusto-conical shape. The outlet 146 may be formed as a vertically oriented tube with a reducer at its top. The upper opening 148 is smaller than the lower opening 147.

[0199]

[0219] The positioning of outlet 146 can advantageously help minimize the amount of solid particles entrained in the liquid withdrawn through outlet 146 and carried to reheater recycle loop 26. This positioning can help reduce plugging of the reheater, recycle loop 26, pump 27 of recycle loop 26, and heater 28 of recycle loop 26.

[0200]

[0220] A greater portion of the liquid flows to the outlet through lower opening 147, which is larger than upper opening 146, i.e., upper opening 148 is reduced in size compared to lower opening 147. The reduced size of upper opening 148 can advantageously force circulation of the liquid to the top of the vessel. This reduction can also help reduce gas entrainment in the extracted liquid stream that is removed to recycle loop 26.

[0201]

[0221] Due to the progression of pyrolysis in separator vessel 12, pyrolysis gases are generated in the liquid, creating a two-phase mixture of gas bubbles 149 in the liquid. Entraining gas bubbles in the flow to recycle reheat loop 26 is undesirable for several reasons. The gas could cause cavitation or other difficulties in pump 27. It is preferable that the gas be cracked sufficiently to exit separation vessel 12 and head toward the partial condenser, and not be further heated and cracked into shorter chains. The reduced-size upper opening 148 at the top of outlet 146 reduces intake into the outlet from above, yet allows gas bubbles to pass toward the top of separation vessel 12, as shown in FIG. 14 . A low flow rate to the outlet also helps reduce gas intake, since it allows the gas to rise quickly enough.

[0202]

[0222] The ratio of the open area of ​​the lower opening 147 to the open area of ​​the upper opening 148 is preferably greater than 1, preferably greater than 1.5, more preferably greater than 2, more preferably greater than 4.

[0203]

[0223] Referring to FIG. 15, there is shown a shroud 150 positioned around the outlet 146 that encloses or defines the volume around the outlet 146 in the separation vessel 12 .

[0204]

[0224] The shroud 150, shown in its preferred form as a duct, preferably a cylindrical duct or tube having open upper and lower ends, can advantageously help limit the entrainment of solid particles into the liquid withdrawn through the outlet 146.

[0205]

[0225] The shroud 150 is preferably substantially concentric with the outlet 146 , which itself is preferably radially centered in the separator vessel 12 .

[0206]

[0226] The shroud 150 inside the separator vessel 12 is preferably at least partially submerged in the liquid in the separator vessel 12. This preferably defines a radially inner portion of the liquid volume having a concentration of solid particles, which is lower than the concentration of solid particles in the radially outer volume of the liquid. This is achievable because solid particles in the separator vessel 12 tend to be centrifuged to the periphery of the separator vessel 12. The solid particles tend to sink radially outward of the shroud 150, and the shroud 150 can help limit or prevent radial intrusion of solid particles toward the outlet 146. Liquid with a relatively low solid particle concentration can be withdrawn from a low kinetic energy zone of the shroud 150 (lower flow velocity than the exterior of the shroud 150) at the opening of the internal liquid outlet 128, as illustrated by arrow 145 in FIG. 15 .

[0207]

[0227] The shroud 150 inside the separator vessel 12 is preferably completely submerged in the liquid in the separator vessel 12. Liquid can then easily escape from the top of the shroud 150 or the bottom of the shroud 150, which can help avoid dead or stagnant zones of liquid.

[0208]

[0228] The flow pattern of the liquid around the shroud 150 is illustrated in Figure 16. The circular flow tends to centrifuge solid particles radially outward, while the fluid in the shroud 150 is protected from the moving or kinetic energy or solid particles.

[0209]

[0229] The shroud 150 may partially or completely surround the liquid exit point. The shroud 150 may have a substantially solid wall or a porous wall with filter holes.

[0210]

[0230] Preferably, the wall or walls of the shroud 150 are substantially vertical, which can help limit or avoid fouling with solid materials. Typically, the walls are thin to minimize flow interruption and minimize horizontal surfaces.

[0211]

[0231] Preferably, the wall or walls of the shroud 150 are smooth to minimize or avoid fouling. Preferably, the surface roughness of the wall or walls is less than Ra 25 μm, preferably less than Ra 15 μm, more preferably less than Ra 12 μm, even more preferably less than Ra 10 μm, even more preferably less than 6 μm, and even more preferably less than Ra 4 μm.

[0212]

[0232] Without wishing to be bound by theory, the shroud 150 may help improve or maintain separation of liquids and solids in the separator vessel 12, which may reduce or prevent plugging of components in the recycle reheat loop 26. The shroud 150 may also improve tolerance to high solid particle concentrations in the separator vessel 12 and help reduce the overall purge volume from the carbon outlet 129, which may increase product yields.

[0213]

[0233] Alternatively, or in addition to the internal liquid outlet 128, a side liquid outlet 127 is substantially flush with the interior wall of the separator vessel 12. The side liquid outlet 127 is positioned below the liquid level 141 in the separator vessel 12 to allow liquid to be withdrawn, and preferably above the level of the conical bottom 133 or settling zone to reduce entrapment of settled solid particles in the conical bottom section 133.

[0214]

[0234] During operation, it is possible to use either or both of the internal liquid outlet 128 and the side liquid outlet 127. When both are used, the liquid withdrawal ratio can be 100:0 to 0:1000, 90:10 to 10:90, or preferably 60:40 to 40:60, preferably about 50:50.

[0215]

[0235] The withdrawal of liquid through the side liquid outlets 129 and / or the ratio of withdrawal between the outlets can favorably affect the velocity and flow pattern in the separator vessel 12. In particular, constructing the side liquid outlets 129 flush with the vessel wall can help create an uninterrupted flow pattern in the vessel.

[0216]

[0236] Withdrawing liquid through two or more liquid outlets, either internal or on the side, can be advantageous because of the reduced pressure drop across the pump 27 .

[0217]

[0237] 17, as discussed, solid particles present in or generated in the pyrolysis liquid in separation vessel 12 will tend to fall to the bottom of separation vessel 12 and settle and accumulate in the illustrated lower conical section 133 where the fluid flow is lower energy or slower and more gentle. The liquid containing a high concentration of solid particles can be discharged via carbon discharge point 129.

[0218]

[0238] Research has revealed that bottlenecks can occur in the discharge of the carbon particle-rich liquid through the carbon discharge point 129. The provision of bitumen circulation nozzles 130, 131 can help achieve more effective discharge of the particle-rich liquid, thus providing a more robust and less maintenance-intensive apparatus and process. Bitumen or high solids material at the base of the separator vessel 12 can be recirculated through the bitumen circulation nozzles 130, 131 to reduce or prevent gelation, clumping, coagulation, etc. in dense materials. This recirculation can help prevent blockage of the carbon outlet 129.

[0219]

[0239] The high solids liquid is removed via a carbon discharge point 129 and can be recycled through a line for re-entry via bitumen circulation nozzles 130, 131.

[0220]

[0240] The high solids liquid may be reheated or cooled before being returned to separator vessel 12. A heater or cooler may be provided for that purpose. In this way, the temperature in separator vessel 12 can be at least partially controlled or influenced.

[0221]

[0241] The high solids liquid may be sampled or monitored by one or more sensors during recirculation to determine the concentration of solid particles. This may assist in accurately determining the volume of high solids liquid for disposal to avoid excessive buildup of solid particles in the separator vessel 12. This may assist in providing efficient pyrolysis by more limited loss of hydrocarbon products to the purge stream and / or reducing maintenance operations such as cleaning or unplugging.

[0222]

[0242] The return line may be provided with a sample point 557. Sensors may include density sensors, turbidity sensors, viscosity sensors, flow sensors, spectrometers, radioactivity sensors, ultrasound, and the like.

[0223]

[0243] Circulation of bitumen or high solids material at the base of separator vessel 12 may also be advantageous as a means of maintaining or providing heat and kinetic energy to the lower portion of separator vessel 12 during (temporary) shutdown, slowdown, or startup procedures. This can reduce or prevent plugging of the base of separator vessel 12 because hydrocarbons remain liquid and solids remain suspended.

[0224]

[0244] 18-20, the liquid level in the separator vessel 12 can be measured in several different ways. While several alternatives are shown, other alternatives can be considered. For accuracy, more than one or all of the alternatives discussed can be implemented.

[0225]

[0245] The liquid level in the separation vessel 12 is complex to measure: some sensors can fail due to contamination or deteriorate due to harsh conditions, and other sensors can give false readings and be inaccurate due to foaming on the liquid surface.

[0226]

[0246] A radar measurement device, preferably a guided wave radar measurement, may be provided.

[0227]

[0247] The guided wave radar measurement instrument is installed inside the isolation vessel 12. A guided wave radar level transmitter is installed on top. The guided wave radar measurement instrument can provide a wide operating range with good reliability. In particular, rod-type guided wave radar is suitable for operation in foaming liquids, and the measurement instrument operates independently of noise, pressure, temperature, and density fluctuations. Furthermore, contamination of the guided wave radar probe or the inner surface of the isolation vessel has minimal impact on measurement accuracy.

[0228]

[0248] Guided wave radar measuring instruments are used as measuring devices for level control in the reactor vessel.

[0229]

[0249] FIG. 18 illustrates a temperature measuring level sensor device, preferably a multi-point temperature measuring sensor device.

[0230]

[0250] A multi-point temperature measuring device is installed within the crack reactor. A multi-point temperature communicator 300 is preferably located at the nozzle 301. A temperature rod 302 is attached to the top of the vessel. The temperature measuring rod 302 is equipped with a series of separate temperature sensors, e.g., two or more, five or more, or about twelve or more, spaced along the length of the rod 302. The liquid level can be assessed based on the temperature difference between adjacent sensors on the rod 302. Research and practice have shown that the liquid phase is typically, if not always, several degrees warmer than the vapor phase, e.g., 3°C to 6°C.

[0231]

[0251] The accuracy of the temperature measurement will depend on the number of temperature sensors provided on the rod 302 and the spacing of the temperature sensors.

[0232]

[0252] An additional benefit of temperature-based liquid level measurement is that it simultaneously provides information about the overall pyrolysis process in separator vessel 12, especially during start-up or transient conditions. During start-up, for example, the bottom of the vessel may remain cooler than the liquid higher in the vessel. This can occur due to the greater density of the cold liquid. Multiple temperature feedback from rod 302 can alert the operator to sub-prime conditions in separator vessel 12.

[0233]

[0253] An external radiation measuring device, preferably an external gamma source level measuring device, is illustrated in Figure 19. The key to Figure 19 shows radiation 560 and liquid level 561.

[0234]

[0254] The illustrated separation vessel 12 is equipped with an external radioactivity level measurement device comprising a radiation source 305 (preferably a gamma or X-ray source) and a radiation detector 306. The radioactivity level measurement has been found to provide accurate liquid level measurements despite the dynamic processes and conditions of the pyrolysis zone, including foaming and potential fouling. Notably, the radioactivity level measurement does not require an internal probe or other internal sensor.

[0235]

[0255] Mass-based measurement is illustrated in Figure 20. The mass of the liquid, and therefore the liquid level, can be determined based on the determined mass. A load cell 310 is positioned to measure the weight of the separator vessel 12. The load cell 310 is positioned on a support for the reactor vessel.

[0236]

[0256] As an alternative or complementary measurement, the separator vessel may be provided with a differential pressure measurement. Based on the differential pressure measurement and the density of the liquid, the liquid level can be calculated. This calculation can be performed, for example, in one of two ways. One way is to provide a pressure sensor at the bottom of the separator vessel 12 and a pressure sensor (optionally in the gas phase) at the top of the separator vessel 12. By determining the differential pressure in combination with the density of the liquid, the liquid level can be derived.

[0237]

[0257] The described separation vessel is further advantageous in that it is reliable, safe, and easy to achieve start-up. The start-up process may include the following steps: adding diesel or similar heavy hydrocarbon liquid to separator vessel 12 to a predetermined level, circulating and heating the liquid via reheat recycle loop 26 to achieve an above-ambient start-up temperature, and initiating the supply of fresh feed to separator vessel 12.

[0238]

[0258] Starting with higher boiling hydrocarbons such as paraffins (boiling point >370°C), as may be supplied from the reheater / reboiler 16, may be advantageous because the reheat recycle loop 26 allows the liquid to be heated to a high temperature, allowing the start-up liquid in the separator vessel to reach temperatures approaching pyrolysis, e.g., about 350°C-370°C, before fresh plastic feedstock is introduced into the separator vessel 12.

[0239]

[0259] Starting with higher boiling hydrocarbons can also help protect the pump, which may otherwise suffer from cavitation if too many more boiling components are involved.

[0240]

[0260] All documents cited in this detailed description of the present invention are, in relevant part, incorporated herein by reference, and the citation of any document shall not be construed as an admission that such citation is prior art with respect to the present invention. To the extent that a meaning or definition of a term within a document of this document conflicts with a meaning or definition of a term in a document incorporated by reference, the meaning or definition assigned to the term in this document shall control.

[0241]

[0261] While particular embodiments of the present invention have been illustrated and described, it would be obvious to those skilled in the art that various other changes and modifications can be made without departing from the spirit and scope of the invention. It is, therefore, intended in the appended claims to cover all such changes and modifications that are within the scope of this invention.

[0242]

[0262] The following clauses refer to various aspects of the present invention.

[0243]

[0263] Clause 0.1: A method for the pyrolysis of plastic materials, the method comprising: heating the plastic material to a pyrolysis temperature to result in a fluid stream of at least partially pyrolyzed material comprising liquid and gaseous hydrocarbons; injecting the fluid stream of liquid and gaseous hydrocarbons, preferably under gravity, into a gas-liquid separation vessel where the gaseous and liquid materials separate; discharging the gaseous material from the separation vessel for processing said gaseous material into hydrocarbon products; collecting the liquid in the bottom of a separation vessel and subjecting the liquid to further pyrolysis. wherein a fluid stream of liquid and gaseous hydrocarbons is injected to generate a vortex or cyclone fluid flow in the separation vessel.

[0244]

[0264] Clause 0.2: The method according to clause 0.1, wherein the injection of the fluid stream occurs below the level of the accumulated liquid in the separator vessel.

[0245]

[0265] Clause 0.3: The method of clause 0.1 or 0.2, wherein the plastic material is heated to a pyrolysis temperature of about 360°C to about 550°C, preferably about 390°C to about 450°C, before being poured into the separation vessel.

[0246]

[0266] Clause 0.4: A method according to any one of clauses 0.1 to 0.3, wherein the step of injecting the fluid streams of liquid and gaseous hydrocarbons into the gas-liquid separation vessel comprises injecting the fluid streams substantially tangentially to the inner surface of the separation vessel, and preferably the separation vessel has a substantially circular cross-section, at least at the injection point.

[0247]

[0267] Clause 0.5: The method of any one of clauses 0.1 to 0.4, wherein the step of heating the plastic material to a pyrolysis temperature to provide a stream of pyrolyzed gaseous hydrocarbons comprises heating the plastic material to a pyrolysis temperature in one or more heat exchangers, preferably a plurality of heat exchangers arranged in series, to provide a stream of at least partially pyrolyzed gaseous and liquid materials.

[0248]

[0268] Clause 0.6: The method of any one of clauses 0.1 to 0.5, further comprising the steps of removing the accumulated liquid material from the separation vessel, reheating the liquid material to pyrolysis temperatures, and returning the liquid material to the separation vessel as a second fluid stream comprising liquid and gaseous hydrocarbons.

[0249]

[0269] Clause 0.7: The method of clause 0.6, wherein a second fluid stream is separately injected into a gas-liquid separation vessel, and the gaseous and liquid materials are separated.

[0250]

[0270] Clause 0.8: The method of clause 0.6 or 0.7, wherein a second fluid stream of liquid and gaseous hydrocarbons is injected to generate or enhance a vortex or cyclonic fluid flow in the separation vessel.

[0251]

[0271] Clause 0.9: The method of any one of clauses 0.1 to 0.8, wherein pyrolysis generates solid carbon particles in the fluid stream and the vortex or cyclone fluid flow forces the solid carbon particles radially outward, preferably causing the solid particles to settle at the base of the method of any one of clauses 0.1 to 0.8.

[0252]

[0272] Clause 0.10: The method of any one of clauses 0.1 to 0.9, comprising providing a raw plastic material, the raw plastic material comprising polyethylene and / or polypropylene plastic, preferably wherein the sum of the polyethylene and polypropylene in the raw material is at least 50% by weight, more preferably at least 60% by weight of the weight of the raw material.

[0253]

[0273] Clause 0.11: The method of clause 0.10, wherein the feedstock comprises polyvinyl chloride plastic, preferably greater than 1 wt.%, more preferably greater than 5 wt.%, of polyvinyl chloride plastic, or the feedstock comprises less than 5 wt.%, more preferably less than 1 wt.%, of polyvinyl chloride plastic.

[0254]

[0274] Clause 0.12: The method of clause 10 or 11, wherein the feedstock comprises polyethylene terephthalate plastic, preferably more than 3% by weight, more preferably more than 4% by weight, of polyethylene terephthalate plastic, or the feedstock comprises less than 4% by weight, more preferably less than 3% by weight of polyethylene terephthalate plastic.

[0255]

[0275] Clause 0.13: The method of clause 10, 11 or 12, wherein the feedstock comprises polystyrene plastic, preferably more than 1 wt%, more preferably more than 5 wt%, of polystyrene plastic, or the feedstock comprises less than 20 wt%, more preferably less than 5 wt%, of polystyrene plastic.

[0256]

[0276] Clause 0.14: A method for producing hydrocarbon materials comprising the steps of any one of clauses 0.1 to 0.13 and the further step of distilling gaseous hydrocarbons in a distillation apparatus to obtain hydrocarbon products, preferably wherein the hydrocarbon products comprise butane, propane, kerosene, diesel, fuel oil; light distillates, such as LPG, gasoline, naphtha or mixtures thereof; medium distillates, such as kerosene, jet fuel, diesel or mixtures thereof; heavy distillates and residues, such as fuel oil, lubricating oil, paraffin, wax, asphalt or mixtures thereof; or any mixtures thereof; hydrocarbons, whether saturated, unsaturated, linear, cyclic or aromatic; non-condensable gases, including methane, ethane, ethene and / or other small molecules; and mixtures thereof.

[0257]

[0277] Clause 0.15: An apparatus for pyrolysis of waste plastics into one or more hydrocarbon products, preferably at least one or more liquid hydrocarbon products, comprising: a heating device, preferably a heat exchanger, for receiving and heating the waste plastic to pyrolysis temperatures; a separator vessel downstream of the heating device, the separator device comprising: an inlet positioned to receive gaseous and liquid plastic waste at pyrolysis temperatures from the heating device; an upper outlet for the gaseous material to exit; and Lower outlet for liquid material Equipped with The apparatus, wherein the inlet is positioned to inject gaseous and liquid plastic waste from the heating device to generate a vortex or cyclone fluid flow in the separation vessel.

[0258]

[0278] Clause 0.16: The apparatus of clause 0.15, wherein the heating device is configured to heat the waste plastic to a pyrolysis temperature of about 360°C to about 550°C, preferably about 390°C to about 450°C.

[0259]

[0279] Clause 0.17: An apparatus as described in clause 0.15 or 0.16, wherein the inlet is arranged to inject gaseous and liquid plastic waste from the heating device substantially tangentially to the inner surface of the separation vessel, and preferably the separation vessel has a substantially circular cross section, at least at the injection point.

[0260]

[0280] Clause 0.18: An apparatus according to any one of clauses 0.15 to 0.17, wherein the heating device comprises one or more heat exchangers, preferably a tube-in-shell heat exchanger, more preferably several heat exchangers arranged in series.

[0261]

[0281] Clause 0.19: An apparatus as described in any one of clauses 0.15 to 0.18, wherein the separation vessel is elongated and vertically arranged so that the pyrolyzed gaseous and liquid materials separate under gravity, with the pyrolyzed gaseous material proceeding upward to the upper outlet and the liquid material proceeding downward.

[0262]

[0282] Clause 1.1: A method for the pyrolysis of plastic materials, the method comprising: heating the plastic material to a pyrolysis temperature to result in a fluid stream of at least partially pyrolyzed material comprising liquid and gaseous hydrocarbons; passing the fluid stream of liquid and gaseous hydrocarbons, preferably under gravity, to a gas-liquid separation vessel where the gaseous and liquid materials separate; discharging the gaseous material from the separation vessel for processing said gaseous material into hydrocarbon products; collecting the liquid in the bottom of a separation vessel and subjecting the liquid to further pyrolysis; withdrawing a portion of the accumulated liquid material from the separation vessel, heating the withdrawn liquid to pyrolysis temperatures, and returning the liquid to the separation vessel as a fluid stream comprising liquid and gaseous hydrocarbons. and withdrawing the accumulated liquid through an outlet inside the separation vessel, preferably an outlet substantially radially central to the separation vessel.

[0263]

[0283] Clause 1.2: The method of clause 1.1, wherein the plastic material is heated to a pyrolysis temperature of about 360°C to about 550°C, preferably about 390°C to about 450°C, before being fed to the separation vessel.

[0264]

[0284] Clause 1.3: The method of clause 1.1 or 1.2, wherein pyrolysis produces solid carbon particles in a separator vessel, and the fluid in the separator vessel is controlled to form a vortex or cyclone fluid that centrifuges the solid carbon particles radially outward.

[0265]

[0285] Clause 1.4: The method of clause 3, wherein an outlet for withdrawal of accumulated liquid is positioned approximately in the central portion of the vortex or cyclone flow.

[0266]

[0286] Clause 1.5: A method according to any one of clauses 1.1 to 1.4, wherein a shroud is provided which at least partially radially surrounds the liquid outlet, and preferably the shroud is partially or completely submerged in the stored liquid.

[0267]

[0287] Clause 1.6: The method of clause 1.5, wherein the shroud at least partially isolates the liquid outlet from the radially outer cyclonic or vortex flow in the separation vessel.

[0268]

[0288] Clause 1.7: The method according to any one of clauses 1.1 to 1.6, wherein the outlet for the stored liquid consists of a vertically arranged cylinder, preferably of circular cross section, having an opening at the upper end of the cylinder and an opening at the lower end of the cylinder.

[0269]

[0289] Clause 1.8: The method of clause 7, wherein the opening at the top end is smaller than the opening at the bottom end.

[0270]

[0290] Clause 1.9: The method of any one of clauses 1.1 to 1.8, wherein the returned fluid stream is injected into a separation vessel to generate or enhance said vortex or cyclone fluid flow in the separation vessel.

[0271]

[0291] Clause 1.10: The method according to any one of clauses 1.1 to 1.9, wherein the injection of the fluid stream takes place below the level of the accumulated liquid in the separator vessel.

[0272]

[0292] Clause 1.11: A method according to any one of clauses 1.1 to 1.10, comprising providing a raw plastic material, the raw plastic material comprising polyethylene and / or polypropylene plastic, preferably the sum of the polyethylene and polypropylene in the raw material being at least 50% by weight, more preferably at least 60% by weight of the weight of the raw material.

[0273]

[0293] Clause 1.12: The method of clause 1.10, wherein the feedstock comprises polyvinyl chloride plastic, preferably greater than 1% by weight, more preferably greater than 5% by weight, of polyvinyl chloride plastic, or the feedstock comprises less than 5% by weight, more preferably less than 1% by weight of polyvinyl chloride plastic.

[0274]

[0294] Clause 1.13: The method of clause 1.10 or 1.11, wherein the feedstock comprises polyethylene terephthalate plastic, preferably more than 3% by weight, more preferably more than 4% by weight, of polyethylene terephthalate plastic, or the feedstock comprises less than 4% by weight, more preferably less than 3% by weight, of polyethylene terephthalate plastic.

[0275]

[0295] Clause 1.14: The method of clause 1.10, 1.11 or 1.12, wherein the feedstock comprises polystyrene plastic, preferably greater than 1% by weight, more preferably greater than 5% by weight, of polystyrene plastic, or the feedstock comprises less than 20% by weight, more preferably less than 5% by weight, of polystyrene plastic.

[0276]

[0296] Clause 1.15: A method for producing hydrocarbon materials comprising the steps of any one of clauses 1.1 to 1.14 and the further step of distilling gaseous hydrocarbons in a distillation apparatus to obtain hydrocarbon products, preferably wherein the hydrocarbon products comprise butane, propane, kerosene, diesel, fuel oil; light distillates, such as LPG, gasoline, naphtha or mixtures thereof; medium distillates, such as kerosene, jet fuel, diesel or mixtures thereof; heavy distillates and residues, such as fuel oil, lubricating oil, paraffin, wax, asphalt or mixtures thereof; or any mixtures thereof; hydrocarbons, whether saturated, unsaturated, linear, cyclic or aromatic; non-condensable gases comprising methane, ethane, ethene and / or other small molecules; and mixtures thereof.

[0277]

[0297] Clause 1.16: An apparatus for pyrolysis of waste plastics into one or more hydrocarbon products, preferably at least one or more liquid hydrocarbon products, comprising: a heating device, preferably a heat exchanger, for receiving and heating the waste plastic to pyrolysis temperatures; a separator vessel downstream of the heating device, the separator device comprising: an inlet positioned to receive gaseous and liquid plastic waste at pyrolysis temperatures from the heating device; an upper outlet for the gaseous material to exit; and Lower outlet for liquid material Equipped with An apparatus in which a lower outlet for exiting the liquid material is positioned within the separation vessel, preferably substantially radially centrally.

[0278]

[0298] Clause 1.17: The apparatus of clause 1.16, wherein the heating device is configured to heat the waste plastic to a pyrolysis temperature of about 360°C to about 550°C, preferably about 390°C to about 450°C.

[0279]

[0299] Clause 1.18: An apparatus as described in clause 1.16 or 1.17, wherein the inlet is arranged to inject gaseous and liquid plastic waste from the heating device substantially tangentially to the inner surface of the separation vessel, and preferably the separation vessel has a substantially circular cross section, at least at the injection point.

[0280]

[0300] Clause 1.19: An apparatus as described in any one of clauses 1.16 to 1.18, wherein the separation vessel is elongated and vertically arranged so that the pyrolyzed gaseous and liquid materials separate under gravity, with the pyrolyzed gaseous material proceeding upward to the upper outlet and the liquid material proceeding downward.

[0281]

[0301] Clause 1.20: An apparatus according to any one of clauses 1.16 to 1.19, wherein the liquid outlet is located below the working liquid level of the separation vessel, and preferably is submerged in use.

[0282]

[0302] Clause 2.1: An apparatus for pyrolysis of waste plastics into one or more hydrocarbon products, preferably at least one or more liquid hydrocarbon products, comprising: a heating device, preferably a heat exchanger, for receiving and heating the waste plastic to pyrolysis temperatures; a separator vessel downstream of the heating device, the separator vessel comprising: an inlet positioned to receive gaseous and liquid plastic waste at pyrolysis temperatures from the heating device; an upper outlet for the gaseous material to exit; and Hollow body with substantially conical base Equipped with The device wherein the substantially conical bottom has an opening angle of about 30° to about 70°.

[0283]

[0303] Clause 2.2: The device according to clause 2.1, wherein the opening angle is between about 50° and about 70°, preferably between about 55° and about 65°, more preferably about 60°.

[0284]

[0304] Clause 2.3: An apparatus according to clause 2.1 or 2.2, wherein the separation vessel has one or more inner walls with a surface roughness of less than Ra 25 μm, preferably less than Ra 15 μm, more preferably less than Ra 12 μm, even more preferably less than Ra 10 μm.

[0285]

[0305] Clause 2.4: An apparatus according to any one of clauses 2.1 to 2.3, wherein the inlet is configured to allow material to enter the separation vessel tangentially.

[0286]

[0306] Clause 2.5: The apparatus of clause 2.4, wherein the inlet is configured to allow material to enter the separation vessel at a velocity high enough to achieve vortex or cyclonic motion of the material in the separation vessel.

[0287]

[0307] Clause 2.6: An apparatus according to any one of clauses 2.1 to 2.5, wherein the bottom of the separation vessel is provided with an outlet, preferably a carbon discharge outlet, arranged to allow material to exit the separation vessel.

[0288]

[0308] Clause 2.7: An apparatus according to any one of clauses 2.1 to 2.6, wherein the system is configured to heat the material.

[0289]

[0309] Clause 2.8: An apparatus according to any one of clauses 2.1 to 2.7, wherein the system is configured to allow material leaving the separation vessel via the outlet to circulate and return to the separation vessel via the inlet.

[0290]

[0310] Clause 2.9: A method for the pyrolysis of plastic materials, the method comprising: heating the plastic material to a pyrolysis temperature to result in a fluid stream of at least partially pyrolyzed material comprising liquid and gaseous hydrocarbons and solid carbon particles; directing the fluid stream, preferably under gravity, to a gas-liquid separation vessel where the gaseous and liquid materials separate; discharging the gaseous material from the separation vessel for processing said gaseous material into hydrocarbon products; collecting the liquid with entrained solid carbon particles at the bottom of a separation vessel and subjecting the liquid to further pyrolysis to produce further solid carbon particles; allowing the solid carbon particles to settle to the bottom of a separation vessel, the bottom being substantially conical, the substantially conical bottom having an opening angle of about 30° to about 70°; and withdrawing at least a portion of the mixture of hydrocarbons and solid carbon particles from the bottom conical portion. A method comprising:

[0291]

[0311] Clause 2.10: The method according to clause 2.9, wherein the plastic material is heated to a pyrolysis temperature of about 360°C to about 550°C, preferably about 390°C to about 450°C, before being fed to the separation vessel.

[0292]

[0312] Clause 2.11: The method of clause 2.9 or 2.10, wherein pyrolysis produces solid carbon particles in a separator vessel, and the fluid in the separator vessel is controlled to form a vortex or cyclone fluid that centrifuges the solid carbon particles radially outward.

[0293]

[0313] Clause 2.12: The method of any one of clauses 2.9 to 2.11, carried out using an apparatus of any one of clauses 2.1 to 2.8.

[0294]

[0314] Clause 2.13: A method for producing hydrocarbon materials comprising the steps of any one of clauses 2.9 to 2.12 and the further step of distilling gaseous hydrocarbons in a distillation apparatus to obtain hydrocarbon products, preferably wherein the hydrocarbon products comprise butane, propane, kerosene, diesel, fuel oil; light distillates, such as LPG, gasoline, naphtha or mixtures thereof; medium distillates, such as kerosene, jet fuel, diesel or mixtures thereof; heavy distillates and residues, such as fuel oil, lubricating oil, paraffin, wax, asphalt or mixtures thereof; or any mixtures thereof; hydrocarbons, whether saturated, unsaturated, linear, cyclic or aromatic; non-condensable gases comprising methane, ethane, ethene and / or other small molecules; and mixtures thereof.

[0295]

[0315] Clause 3.1: A method for the pyrolysis of plastic materials, the method comprising: heating the plastic material to a pyrolysis temperature to result in a fluid stream of at least partially pyrolyzed material comprising liquid and gaseous hydrocarbons; passing the fluid stream of liquid and gaseous hydrocarbons, preferably under gravity, to a gas-liquid separation vessel where the gaseous and liquid materials separate; discharging the gaseous material from the separation vessel for processing said gaseous material into hydrocarbon products; collecting the liquid in the bottom of a separation vessel and subjecting the liquid to further pyrolysis; and determining the liquid level in the separation vessel by radar, radioactivity, temperature, mass and / or pressure measuring devices; A method comprising:

[0296]

[0316] Clause 3.2: The method according to clause 3.1, wherein the liquid level in the separation vessel is controlled by adjusting the rate of pyrolysis, preferably by temperature control.

[0297]

[0317] Clause 3.3: The method of any one of clauses 3.1-3. to any one of clauses 3.1-3.2, wherein the liquid level in the separation vessel is controlled by the rate of introduction of fresh feed.

[0298]

[0318] Clause 3.4: The method of any one of clauses 3.1 to 3.3, wherein the liquid level in the separation vessel is maintained at a predetermined level.

[0299]

[0319] Clause 3.5: A method for producing hydrocarbon materials comprising the steps of any one of clauses 3.1 to 3.5 and the further step of distilling the gaseous hydrocarbons in a distillation apparatus to obtain hydrocarbon products, preferably wherein the hydrocarbon products comprise butane, propane, kerosene, diesel, fuel oil; light distillates, such as LPG, gasoline, naphtha or mixtures thereof; medium distillates, such as kerosene, jet fuel, diesel or mixtures thereof; heavy distillates and residues, such as fuel oil, lubricating oil, paraffin, wax, asphalt or mixtures thereof; or any mixtures thereof; hydrocarbons, whether saturated, unsaturated, linear, cyclic or aromatic; non-condensable gases comprising methane, ethane, ethene and / or other small molecules; and mixtures thereof.

[0300]

[0320] Clause 3.6: An apparatus for pyrolysis of waste plastics into one or more hydrocarbon products, preferably at least one or more liquid hydrocarbon products, comprising: a heating device, preferably a heat exchanger, for receiving and heating the waste plastic to pyrolysis temperatures; a separator vessel downstream of the heating device, the separator vessel comprising: an inlet positioned to receive gaseous and liquid plastic waste at pyrolysis temperatures from the heating device; an upper outlet for the gaseous material to exit; and A liquid level measurement system for determining a liquid level in a separation vessel, the liquid level measurement system comprising one, more than one or all of the devices selected from the group consisting of a radar measurement device, a radioactivity measurement device, a temperature measurement device, a mass measurement device and a differential pressure measurement device. An apparatus comprising:

[0301]

[0321] Clause 3.7: An apparatus according to clause 3.6, wherein the liquid level in the container is measured using at least two, preferably three, devices.

[0302]

[0322] Clause 3.8: An apparatus as described in clause 3.6 or 3.7, wherein the liquid level in the container is measured using a device selected from the group consisting of a guided wave radar measuring device, an external radioactivity level measuring device, a differential pressure measuring device and a multi-point temperature measuring device.

[0303]

[0323] Clause 3.9: The apparatus of any one of clauses 3.6 to 3.8, wherein the system is configured to control the liquid level in the container.

[0304]

[0324] Clause 3.10: An apparatus described in any one of clauses 3.6 to 3.9, wherein the system is further configured to control the pressure within the container.

[0305]

[0325] Clause 3.11: An apparatus as described in clause 3.9 or 3.10, wherein the apparatus controls the liquid level in the vessel by controlling the input rate of fresh feed material entering the separation vessel and / or controlling the output rate of material exiting the vessel via the outlet as gas, liquid or purge.

[0306]

[0326] Clause 3.12: An apparatus according to clause 3.9 or 3.10, wherein the apparatus controls the liquid level in the separation vessel by controlling the inflow rate and / or temperature of the material in the vessel.

[0307]

[0327] Clause 4.1: A method for the pyrolysis of plastic materials, the method comprising: heating the plastic material to a pyrolysis temperature to result in a fluid stream of at least partially pyrolyzed material comprising liquid and gaseous hydrocarbons and solid carbon particles; directing the fluid stream, preferably under gravity, to a gas-liquid separation vessel where the gaseous and liquid materials separate; discharging the gaseous material from the separation vessel for processing said gaseous material into hydrocarbon products; collecting the liquid with entrained solid carbon particles at the bottom of a separation vessel and subjecting the liquid to further pyrolysis to produce further solid carbon particles; allowing the solid carbon particles to settle to the bottom of a separation vessel; and withdrawing at least a portion of the mixture of hydrocarbons and solid carbon particles from the bottom of the separation vessel and recycling said mixture of hydrocarbons and solid carbon particles to said bottom; A method comprising:

[0308]

[0328] Clause 4.2: The method of clause 4.1, wherein the plastic material is heated to a pyrolysis temperature of about 360°C to about 550°C, preferably about 390°C to about 450°C, before being poured into the separation vessel.

[0309]

[0329] Clause 4.3: The method of clause 4.1 or 4.2, wherein the fluid in the separator vessel is controlled to form a vortex or cyclone fluid flow that centrifuges the solid carbon particles radially outward.

[0310]

[0330] Clause 4.4: The method of any one of clauses 4.1 to 4.3, wherein in the step of withdrawing and recycling the mixture of hydrocarbons and solid carbon particles, the hydrocarbons and solid carbon particles are withdrawn from the bottom of a separation vessel, recycled, and injected into the separation vessel at a location that is above a bottom withdrawal point and below the liquid level in the separator vessel, and preferably below an outlet for withdrawing from the separation vessel a portion of the accumulated liquid material having a lower concentration of solid particles.

[0311]

[0331] Clause 4.5: The method of any one of clauses 4.1 to 4.4, further comprising determining a property of the extracted mixture of hydrocarbons and solid carbon particles, preferably the content mixture, more preferably a property indicative of the concentration or particle size of the coke, charcoal or solid particles.

[0312]

[0332] Clause 4.6: The method of clause 4.5, wherein the step of determining the content of the mixture includes one or more of density analysis, turbidity analysis, viscosity analysis, spectrometric analysis, radioactivity analysis and / or ultrasonic analysis.

[0313]

[0333] Clause 4.7: The method of any one of clauses 4.1 to 4.6, wherein the ratio of the withdrawn mixture to the returned mixture is determined based on analysis of one or more properties of the mixture, and optionally a portion of the withdrawn mixture is discharged, more preferably purged, preferably wherein said one or more properties are indicative of the concentration or size of solid carbon particles in said mixture.

[0314]

[0334] Clause 4.8: The method of any one of clauses 4.1 to 4.7, comprising heating the mixture during recirculation outside the separation vessel.

[0315]

[0335] Clause 4.9: The method of any one of clauses 4.1 to 4.8, comprising providing a raw plastics material, the raw plastics material comprising polyethylene and / or polypropylene plastic, preferably wherein the sum of the polyethylene and polypropylene in the raw material is at least 50% by weight, more preferably at least 60% by weight of the weight of the raw material.

[0316]

[0336] Clause 4.10: The method of clause 4.9, wherein the feedstock comprises polyvinyl chloride plastic, preferably more than 1 wt.%, more preferably more than 5 wt.%, of polyvinyl chloride plastic, or the feedstock comprises less than 5 wt.%, more preferably less than 1 wt.%, of polyvinyl chloride plastic.

[0317]

[0337] Clause 4.11: The method of clause 4.9 or 4.10, wherein the feedstock comprises polyethylene terephthalate plastic, preferably more than 3% by weight, more preferably more than 4% by weight, of polyethylene terephthalate plastic, or the feedstock comprises less than 4% by weight, more preferably less than 3% by weight, of polyethylene terephthalate plastic.

[0318]

[0338] Clause 4.12: The method of clause 4.10, 4.11 or 4.12, wherein the feedstock comprises polystyrene plastic, preferably greater than 1% by weight, more preferably greater than 5% by weight, of polystyrene plastic, or the feedstock comprises less than 20% by weight, more preferably less than 5% by weight, of polystyrene plastic.

[0319]

[0339] Clause 4.13: A method for producing hydrocarbon materials comprising the steps of any one of clauses 4.1 to 4.12 and the further step of distilling the hydrocarbons in a distillation apparatus to obtain hydrocarbon products, preferably wherein the hydrocarbon products comprise butane, propane, kerosene, diesel, fuel oil; light distillates, such as LPG, gasoline, naphtha or mixtures thereof; medium distillates, such as kerosene, jet fuel, diesel or mixtures thereof; heavy distillates and residues, such as fuel oil, lubricating oil, paraffin, wax, asphalt or mixtures thereof; or any mixtures thereof; hydrocarbons, whether saturated, unsaturated, linear, cyclic or aromatic; non-condensable gases, including methane, ethane, ethene and / or other small molecules; and mixtures thereof.

[0320]

[0340] Clause 4.14: An apparatus for pyrolysis of waste plastics into one or more hydrocarbon products, preferably at least one or more liquid hydrocarbon products, comprising: a heating device, preferably a heat exchanger, for receiving and heating the waste plastic to pyrolysis temperatures; a separator vessel downstream of the heating device, the separator device comprising: an inlet positioned to receive gaseous and liquid plastic waste at pyrolysis temperatures from the heating device; an upper outlet for the gaseous material to exit; a carbon outlet at the base of the separator vessel for withdrawing the mixture of hydrocarbons and solid carbon particles from the bottom of the separator vessel; one or more recirculation nozzles positioned at the bottom of the separation vessel for injecting at least a portion of the withdrawn mixture into the separation vessel; An apparatus comprising:

[0321]

[0341] Clause 4.15: The apparatus of clause 14, wherein the heating device is configured to heat the waste plastic to a pyrolysis temperature of about 360°C to about 550°C, preferably about 390°C to about 450°C.

[0322]

[0342] Clause 4.16: The apparatus of clause 4.14 or 4.15, further comprising a sample point or station for determining a property of the withdrawn mixture, preferably a property indicative of the concentration or size of solid carbon particles in the mixture.

[0323]

[0343] Clause 4.17: The apparatus of clause 4.16, further comprising at least one sensor selected from a density sensor, a turbidity sensor, a flow sensor, a spectrometer, a radioactivity sensor and / or an ultrasonic sensor.

[0324]

[0344] Clause 4.18: An apparatus according to any one of clauses 4.14 to 4.18, wherein the separation vessel is elongated and vertically arranged so that the pyrolyzed gaseous and liquid materials separate under gravity, with the pyrolyzed gaseous material proceeding upward to the upper outlet and the liquid material proceeding downward.

Claims

1. An apparatus for thermally decomposing waste plastic into one or more hydrocarbon products, preferably at least one or more liquid hydrocarbon products, wherein the apparatus is A heating device, preferably a heat exchanger, for receiving waste plastic and heating it to a thermal decomposition temperature. The heating device is further comprising a separator container downstream of the heating device, and the separator container is An inlet is arranged to receive gaseous and liquid plastic waste at the thermal decomposition temperature from the aforementioned heating device. An upper outlet for the release of gaseous material, and A hollow body with a substantially conical base Equipped with, The apparatus wherein the substantially conical base has an opening angle of approximately 30° to approximately 70°.

2. The apparatus according to claim 1, wherein the opening angle is approximately 50° to approximately 70°, preferably approximately 55° to approximately 65°, and more preferably approximately 60°.

3. The apparatus according to claim 1 or 2, wherein the separation container has one or more inner walls having a surface roughness of Ra less than 25 μm, preferably less than 15 μm, more preferably less than 12 μm, and even more preferably less than 10 μm.

4. The apparatus according to claim 1 or 2, wherein the inlet is configured to allow the material to enter the separation container in a tangential direction.

5. The apparatus according to claim 4, wherein the inlet is configured to allow the material to enter the separation container at a speed high enough to achieve a vortex or cyclone motion of the material in the separation container.

6. The apparatus according to claim 1 or 2, wherein the bottom of the separation container is provided with an outlet, preferably a carbon discharge outlet, arranged to allow the material to exit the separation container.

7. The apparatus according to claim 1 or 2, wherein the system is configured to heat the material.

8. The apparatus according to claim 1 or 2, wherein the system is configured to allow material that has exited the separation container via an outlet to circulate and return to the separation container via an inlet.

9. A method for the thermal decomposition of plastic materials, A step of heating a plastic material to a thermal decomposition temperature to produce a fluid flow of at least partially thermally decomposed material containing liquid and gaseous hydrocarbons and solid carbon particles, The step of sending the aforementioned fluid flow, preferably under gravity, to a gas-liquid separation container in which the gaseous and liquid materials are separated, A step of releasing the gaseous material from the separation container in order to process the gaseous material to obtain a hydrocarbon product, The steps include: storing the liquid containing the entrained solid carbon particles at the bottom of the separation container, and subjecting the liquid to further thermal decomposition to generate even more solid carbon particles; A step of allowing the solid carbon particles to settle at the bottom of the separation container, wherein the bottom is substantially conical, and the substantially conical bottom has an opening angle of about 30° to about 70°, and Step 1: Extracting at least a portion of the mixture of hydrocarbons and solid carbon particles from the bottom cone-shaped portion. Methods that include...

10. The method according to claim 9, wherein the plastic material is heated to a thermal decomposition temperature of about 360°C to about 550°C, preferably about 390°C to about 450°C, before being supplied to the separation container.

11. The method according to claim 9 or 10, wherein solid carbon particles are generated in the separator container by the thermal decomposition, and the fluid in the separator container is controlled to form a vortex or cyclone fluid that centrifuges the solid carbon particles radially outward.

12. The method according to claim 9 or 10, performed using the apparatus described in claim 1 or 2.

13. A method for producing a hydrocarbon material, comprising the steps described in claim 9 or 10, and a further step of distilling a gaseous hydrocarbon in a distillation apparatus to obtain the hydrocarbon product, wherein the hydrocarbon product preferably comprises butane, propane, kerosene, diesel, fuel oil; light distillates, e.g., LPG, gasoline, naphtha, or mixtures thereof; medium distillates, e.g., kerosene, jet fuel, diesel, or mixtures thereof; heavy distillates and residues, e.g., fuel oil, lubricating oil, paraffin, wax, asphalt, or mixtures thereof; or any mixture thereof; saturated, unsaturated, linear, cyclic, or aromatic hydrocarbons; non-condensable gases including methane, ethane, ethene, and / or other small molecules; and mixtures thereof.

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