System for separating gas, liquid and solid particles in material

Abstract

There is provided a method for pyrolyzing a plastic material, the method comprising the steps of:-heating the plastic material to a pyrolysis temperature to provide a fluid stream comprising liquid and gaseous hydrocarbons of the at least partially pyrolyzed material; -passing the fluid stream of liquid and gaseous hydrocarbons into a gas-liquid separation vessel, wherein the gaseous and liquid materials are separated preferably under the action of gravity; -releasing the gaseous material from the separation vessel for processing the gaseous material into a hydrocarbon product; -accumulating the liquid in a bottom portion of the separation vessel and subjecting the liquid to further pyrolysis; and-determining the liquid level in the separation vessel by means of radar, radioactivity, temperature, mass and / or pressure measurements.

Description

Technical Field

[0001] The present invention generally relates to methods and apparatuses for pyrolyzing waste plastics, and products obtained therefrom. More specifically, the present invention relates to methods and apparatuses for preheating streams of plastics and plastic-derived hydrocarbons undergoing pyrolysis. More particularly, the present invention relates to effective phase separation of plastic-derived hydrocarbons and / or completion of pyrolysis. Additionally, the present invention relates to a system for separating gases, liquids, and optionally solid particles in a material. The present invention also relates to a method and system for cracking long-chain hydrocarbons and separating the resulting products, and particularly relates to a method and system for treating plastics and polyolefins by cracking. Background Art

[0002] Today's society generates a large amount of waste plastics. Although plastic recycling is becoming increasingly efficient and effective, there are still situations where many waste plastics cannot be recycled effectively or efficiently and are disposed of in landfills, where the waste plastics take many years to degrade or may leak into the environment, where it can cause damage to the ecosystem.

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

[0004] The output of plastic-to-chemicals plants typically includes light hydrocarbons (LHC), heavy hydrocarbons (HHC), char, and non-condensable (gases). Currently, LHC, HHC, or their mixtures are the most popular products, but this is market-dependent.

[0005] The industry requires the LHC and HHC fractions 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. Different customers or end uses may expect different qualities, but it is very important for plastic-to-chemicals plants to produce products with stable quality. The final quality of the product fractions is controlled by distillation columns, such as those well-known and commonly used in the petrochemical industry. It is desirable for the fractions to be relatively pure, such that the light hydrocarbon fraction and the heavy hydrocarbons do not contain most of the 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] In a plastic-to-chemicals plant, the feedstock plastics form the input, which may consist mostly of polyethylene and polypropylene for domestic sources. These plastics, which are composed of extremely long-chain hydrocarbons, are then cracked into shorter chains, forming a series of molecules with a variety of chain lengths. As is known, these mixtures can be distilled into various temperature-defined fractions.

[0007] Processes known in the art for converting waste plastics into other substances such as diesel are thermochemical decomposition processes, i.e., pyrolysis. Pyrolysis is the thermal decomposition of waste plastics in an inert atmosphere. In fact, the long polymer chains of the plastic polymers are cracked by heating, resulting in shorter hydrocarbon chains, which are generally more useful as products.

[0008] Pyrolysis is the preferred method for performing the thermochemical decomposition of waste plastic materials. Various attempts have been made previously to provide a technically and cost-effective pyrolysis of waste plastics.

[0009] The techniques discussed in patent publications US2018 / 0010050 and WO2021053139 have achieved technically useful results, the contents of which are incorporated herein by reference.

[0010] US2018 / 0010050A1 discusses a method for recovering hydrocarbons from plastic waste, especially polyolefin-rich waste, by pyrolysis without using a catalyst. The method involves melting the plastic waste in two heating devices and mixing the stream from the cracking reactor with the incoming molten plastic waste of the first heating device. The heated molten plastic is transferred to the cracking reactor, where the plastic material is cracked. Subsequently, the cracked material is distilled into diesel and low-boiling compounds.

[0011] WO 2021 / 053139 Al has many improvements over US2018 / 0010050A1 and, among other things, discusses a method for decomposing long-chain hydrocarbons from plastic-containing waste, the method comprising: 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 in the material begin to crack into shorter chains; and for a specific volume at a temperature higher than the cracking temperature, exposing the specific volume to heat not exceeding 50°C higher than the temperature of the specific volume. After the specific volume of the material has been exposed to the heat, WO 2021 / 053139 transfers the partially cracked molten plastic stream to a gas-liquid separation structure. The separation structure, also known as a reactor, includes a separation zone containing a gas-liquid interface and a settling zone for the accumulation of heavy hydrocarbons and / or solid carbon, and potentially other solids such as aluminum, sand, dirt, etc.

[0012] Although good results have been achieved based on the above technologies, there is still room for further improvement. For example, it would be useful to provide a more general system and process than the previously attempted systems.

[0013] EP 2 876 146 Bl discusses tested technologies, where the process for recovering hydrocarbons from polyolefin plastic recyclables by pyrolytic cracking includes: introducing the plastic recyclables into a mixing vessel under an inert gas and mixing with diesel; removing water vapor in a first heating zone; removing acidic gases in a second heating zone; liquefying those plastic recyclables that have not melted in a third heating zone; cracking the plastic recyclables in a cracking reactor at about 400 degrees Celsius; performing partial condensation to prevent the emission of paraffin; and fractionating the cracked products.

[0014] While the overall objective of the present invention is an overall system improvement of such pyrolysis processes and equipment, the aspects of improvement may preferably include one or more of the following.

[0015] In one aspect, the object of the present invention is to provide alternatives for, and preferably improvements to, pyrolysis processes and equipment. These can solve the separation problems of the cracked plastic stream and / or gases, liquids, and solid particles in the system for cracking long-chain hydrocarbons. The object of the present invention is also to provide an improved method for decomposing long-chain hydrocarbons.

[0016] In one aspect of the present invention, it may be useful to reduce or limit carbon formation in the container in which the pyrolyzed gaseous hydrocarbons are separated from the 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 that are sent to distillation and ultimately distilled. For example, this is to achieve a more commercially useful ratio of non-condensable, light hydrocarbon fractions, and heavy hydrocarbon fractions in the product stream.

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

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

[0020] In another aspect of the present invention, in production by pyrolysis processes, for example, it may be advantageous to expand or enrich the available product stream in the production of heavier fractions such as paraffin in a controllable amount.

[0021] A non-limiting object of the present invention is to provide efficient, versatile, and / or robust processes and apparatuses for converting waste plastics into useful product streams, such as non-condensable gases, light hydrocarbons, heavy hydrocarbons, paraffins, asphalt, tar, and other similar derivable fractions. In this regard, the present invention may solve one or more of the foregoing problems, or at least provide a useful alternative in the art.

[0022] Attempts have been made previously to effect efficient pyrolysis of waste plastics.

[0023] An example is discussed in patent publication WO11077419 Al, which relates to a process for treating waste plastics, in which the plastics are melted and then pyrolyzed in an oxygen-free atmosphere in a jacket-heated pyrolysis vessel to provide pyrolysis gas. The pyrolysis gas flows upward through a tube connecting the pyrolysis chamber directly to a contactor vessel, contacts plates in the contactor vessel such that some long-chain gas components condense. The condensed liquid returns directly to the pyrolysis zone by flowing downward through the same tube. The condensed liquid is then reheated and further pyrolyzed within the pyrolysis zone. The short-chain gas components leave the contactor in gaseous form and proceed to distillation.

[0024] WO11077419 Al explains that when a batch is completed, an increased load on the pyrolysis chamber agitator indicates that carbon drying has occurred and the process is ended. The pyrolysis chamber is then purged by operating the twin-screw agitator blades in reverse to remove the carbon, and nitrogen is passed upward through the contactor and directly out to a thermal oxidizer to flush any remaining hydrocarbons, during which stage the pyrolysis vessel and contactor are isolated from the rest of the system. Such a process and system can be problematic and sub-optimal. For example, incorporating an agitator in the pyrolysis chamber and direct jacket heating of the pyrolysis chamber are complex but also necessary. The system also utilizes a specific type of jacket-cooled contactor having inclined and porous cooling contactor baffles to enable the condensed hydrocarbons to return directly from the contactor to the pyrolysis chamber via the same tube used for the pyrolysis gas to enter the contactor. This can be complex; the pyrolysis process results in batch completion with a dry carbon (char) product; and purging associated with extended downtime of the pyrolysis reactor.

[0025] There have been previous attempts to place a fractionator directly on top of a pyrolysis vessel to return heavy hydrocarbons for further cracking. Some of these attempts have been found to be less versatile, less robust, and less efficient compared to the optimal case. Without being bound by theory and through technical research, it has been determined that it is possible that the condensed liquid returned directly from the fractionator to the pyrolysis reaction vessel can cause temperature inconsistencies and heat losses in the pyrolysis zone, which requires complex heat input at the pyrolysis zone, possibly accompanied by hot spots, carbonization, complex agitation, and / or energy losses. It may be desirable to provide a process and system that is less affected by such drawbacks.

[0026] Another example is discussed in CH708681A1, which relates to a process for recovering hydrocarbons from polyolefin plastic recyclables by pyrolytic cracking. The plastic recyclables are introduced into a mixing vessel under an inert gas and mixed with diesel; water vapor is removed in a first heating zone; acidic gases are removed in a second heating zone; those plastic recyclables that have not melted are liquefied in a third heating zone; the plastic recyclables are cracked in a cracking reactor at about 400 °C; partial condensation is carried out to prevent the emission of paraffin; and the cracked products are fractionated.

[0027] The fractionator in CH708681A1 is separate and spaced apart from the pyrolysis reactor, where a connecting pipe guides the pyrolysis gas from the pyrolysis reactor to the fractionator. The fractionator is adjusted so that heavy hydrocarbons that do not have the desired product characteristics are condensed and led back via a separate pipe to the third heating zone, where the heavy hydrocarbons can be further cracked. The additional cracking loop reduces the incorporation of overly heavy hydrocarbons in the product.

[0028] It has been found that attempts to implement concepts related to the concepts disclosed in CH708681A1, while producing products practically, have shown some instability and inefficiency in pyrolysis, such as the need for complex heating in the pyrolysis zone. In addition, due to the differential pressure between the fractionator and the heating zone to which the heavy hydrocarbons are returned, the system of CH708681A1 may be complex to implement.

[0029] Other attempts include US10160920 BB, which employs a sequential cracking process for the thermal cracking of hydrocarbon feedstocks in a cascade of cracking units;

[0030] US2007227874 AA, which discusses a method for recovering fractionated hydrocarbons from recycled plastics; and US5580443 A, which discusses a process for the thermal cracking of low-quality feedstocks containing a relatively large proportion of heavy fractions, such as high-boiling fractions.

[0031] 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. SUMMARY OF THE INVENTION

[0032] Although the invention is defined in the independent claims, other aspects of the invention are set forth in the dependent claims, the drawings, the following description, and the clauses.

[0033] According to one aspect of the invention, there is provided a method for pyrolyzing a plastic material, the method comprising the steps of:

[0034] - heating the plastic material to a pyrolysis temperature to provide a fluid stream comprising liquid hydrocarbons and gaseous hydrocarbons of at least partially pyrolyzed material;

[0035] - injecting the fluid stream of liquid hydrocarbons and gaseous hydrocarbons into a gas-liquid separation vessel, wherein the gaseous material and the liquid material are preferably separated under the action of gravity;

[0036] - releasing the gaseous material from the separation vessel for processing the gaseous material into hydrocarbon products;

[0037] - accumulating the liquid in the bottom portion of the separation vessel and subjecting the liquid to further pyrolysis;

[0038] wherein the fluid stream of liquid hydrocarbons and gaseous hydrocarbons is injected to create a vortex or swirl fluid flow in the separation vessel.

[0039] The vortex or swirl can assist in achieving efficient phase separation of the flow, where the denser liquid is driven to the periphery while the gas rises upward. It can further assist in heat distribution and / or effective sinking of solid particles within the liquid body.

[0040] The liquid and entrained solids (and / or solids such as carbon generated during pyrolysis) can thus be collected at the bottom portion of the separation vessel, where they can be further processed and / or separated.

[0041] The injection of the fluid stream is preferably carried out below the liquid level of the accumulated liquid body in the separation vessel. This can help create a vortex or swirl effect in the accumulated liquid body.

[0042] The fluid stream of liquid hydrocarbons and gaseous hydrocarbons is preferably injected tangentially into the gas-liquid separation vessel substantially at the inner surface of the separation vessel, preferably where the separation vessel has a substantially circular cross-section at least at the injection point. This can further help create a vortex or swirl effect in the accumulated liquid body.

[0043] The portion of the liquid material accumulating in the separation vessel can be removed from the separation vessel, for example, by suction or pumping, reheated to the pyrolysis temperature, and returned to the separation vessel as a second incoming fluid stream containing liquid and gaseous hydrocarbons. This can help reduce any need for heating inside the separation vessel to effect pyrolysis. The second fluid stream can preferably be injected into the gas-liquid separation vessel separately from or alternatively in combination with the first stream.

[0044] In one aspect of the 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:

[0045] - heating means, preferably a heat exchanger, for receiving the waste plastics and heating the waste plastics to the pyrolysis temperature;

[0046] - a separation vessel downstream of the heating means, wherein the separation means comprises:

[0047] - an inlet arranged to receive the gaseous and liquid plastic waste at the pyrolysis temperature from the heating means,

[0048] - an upper outlet for the gaseous material to leave; and

[0049] - a lower outlet for the liquid material to leave;

[0050] wherein the inlet is arranged to inject the gaseous and liquid plastic waste from the heating means to create a vortex or swirling fluid flow in the separation vessel.

[0051] The inlet for the hot liquid plastic waste is preferably arranged to inject substantially tangentially to the inner surface of the separation vessel, and the separation vessel has a substantially circular cross-section at least at the injection point or injection level. This can help achieve a vortex or swirl.

[0052] The separation vessel is preferably elongated and arranged vertically to allow the pyrolyzed gaseous and liquid materials to separate under the action of gravity, with the pyrolyzed gaseous material passing upward to the upper outlet and the liquid material passing downward.

[0053] In one aspect of the invention, there is provided a method for pyrolyzing plastic materials, the method comprising the steps of:

[0054] - heating the plastic materials to the pyrolysis temperature to provide a fluid stream containing liquid and gaseous hydrocarbons of at least partially pyrolyzed materials;

[0055] - transferring the fluid stream of liquid and gaseous hydrocarbons to a gas-liquid separation vessel, wherein the gaseous and liquid materials are preferably separated under the action of gravity;

[0056] - Releasing the gaseous material from the separation vessel for processing the gaseous material into hydrocarbon products;

[0057] - Accumulating the liquid in the bottom portion of the separation vessel and subjecting the liquid to further pyrolysis;

[0058] - Removing a portion of the accumulated liquid material from the separation vessel, heating the removed liquid to the pyrolysis temperature and returning the removed liquid as a fluid stream comprising liquid and gaseous hydrocarbons to the separation vessel;

[0059] Wherein the accumulated liquid is removed via an outlet inside the separation vessel, preferably an outlet located substantially at the radial center within the separation vessel.

[0060] This can assist in achieving removal of the liquid in the separation vessel, which may be used for reheating and has a relatively low solid particle content compared to previous attempts to remove liquid at the inner wall. Preferably, the outlet for removing the accumulated liquid is located in the approximate central portion of the vortex or swirl generated in the vessel, which is a stationary zone where very little liquid movement may occur.

[0061] A shroud may be provided to at least partially radially surround the liquid outlet, preferably partially or completely immersed in the accumulated liquid, which can assist in excluding solid particulates and / or strengthening the stationary zone. Preferably, the shroud at least partially isolates the liquid outlet from the radial outer swirl or vortex in the separation vessel.

[0062] The outlet for the accumulated liquid may preferably comprise a vertically arranged cylinder, preferably having a circular cross-section, with an opening at its upper end and an opening at its lower end. The opening at the upper end is preferably smaller than the opening at the lower end, which can assist in effective liquid removal while allowing gas bubbles to escape upwards into the gas zone in the vessel.

[0063] 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:

[0064] - Heating means, preferably a heat exchanger, for receiving the waste plastics and heating the waste plastics to the pyrolysis temperature;

[0065] - A separation vessel downstream of the heating means, wherein the separation means comprises:

[0066] - An inlet arranged to receive the gaseous and liquid plastic waste at the pyrolysis temperature from the heating means,

[0067] - An upper outlet for the gaseous material to leave; and

[0068] - A lower outlet through which the liquid material exits;

[0069] The lower outlet through which the liquid material exits is located inside the separation container, preferably at the substantially radial center.

[0070] In the device, preferably, the inlet is arranged to inject the gaseous and liquid plastic waste from the heating device substantially tangentially to the inner surface of the separation container, preferably where the separation container has a substantially circular cross-section at least at the injection point or the liquid level.

[0071] The separation container of the present invention is preferably elongated and vertically arranged. This can help the gaseous and liquid materials from pyrolysis to separate under the action of gravity, with the gaseous materials from pyrolysis transferring upward to the upper outlet and the liquid materials transferring downward.

[0072] The liquid outlet is preferably located below the operating liquid level of the separation container and is preferably submerged during use.

[0073] In one aspect of the present invention, there is provided a device for pyrolyzing waste plastics into one or more hydrocarbon products, preferably at least one or more liquid hydrocarbon products, the device comprising:

[0074] - A heating device, preferably a heat exchanger, for receiving the waste plastics and heating the waste plastics to the pyrolysis temperature;

[0075] - A separation container downstream of the heating device, wherein the separation container comprises:

[0076] - An inlet arranged to receive the gaseous and liquid plastic waste at the pyrolysis temperature from the heating device,

[0077] - An upper outlet through which the gaseous material exits; and

[0078] - A hollow body, the bottom portion of which is substantially conical;

[0079] The opening angle of the substantially conical bottom portion is about 30° to about 70°, preferably about 50° to about 70°, preferably about 55° to about 65°, more preferably about 60°. The angle of the cone can help the particulate material to effectively sink into the high solid concentration part of the liquid while minimizing the blockage of the lower outlet.

[0080] In various aspects of the present invention, the separation container has an inner surface, preferably the inner surface of the lower conical portion, with a surface roughness less than Ra 25μm, preferably less than Ra 15μm, more preferably less than Ra12μm, even more preferably less than Ra10μm, even more preferably less than Ra 6μm. The smooth surface can help the particulate material to effectively sink and reduce fouling.

[0081] In one aspect of the present invention, there is provided a method for pyrolyzing plastic materials, the method comprising the steps of:

[0082] - Heating the plastic material to a pyrolysis temperature to provide a fluid stream comprising liquid hydrocarbons and gaseous hydrocarbons of at least partially pyrolyzed material, and solid carbon particles;

[0083] - Transferring the fluid stream to a gas-liquid separation vessel, wherein the gaseous material and the liquid material are preferably separated under the action of gravity;

[0084] - Releasing the gaseous material from the separation vessel for processing the gaseous material into hydrocarbon products;

[0085] - Accumulating the liquid comprising entrained solid carbon particles in the bottom portion of the separation vessel and subjecting the liquid to further pyrolysis, with further formation of solid carbon particles;

[0086] - Settling the solid carbon particles to the bottom portion of the separation vessel, wherein the bottom portion is substantially conical and the opening angle of the substantially conical bottom portion is from about 30° to about 70°;

[0087] And

[0088] - Removing at least a portion of the mixture of hydrocarbons and solid carbon particles from the bottom conical portion.

[0089] In one aspect of the present invention, there is provided a method for pyrolyzing plastic materials, the method comprising the steps of:

[0090] - Heating the plastic material to a pyrolysis temperature to provide a fluid stream comprising liquid hydrocarbons and gaseous hydrocarbons;

[0091] - Transferring the fluid stream of liquid hydrocarbons and gaseous hydrocarbons to a gas-liquid separation vessel, wherein the gaseous material and the liquid material are preferably separated under the action of gravity;

[0092] - Releasing the gaseous material from the separation vessel for processing the gaseous material into hydrocarbon products;

[0093] - Accumulating the liquid in the bottom portion of the separation vessel and subjecting the liquid to further pyrolysis; and

[0094] - Determining the liquid level in the separation vessel by radar measurement, radioactive measurement, temperature measurement, mass measurement, and / or pressure measurement.

[0095] Preferably, the liquid level in the separation vessel is controlled by adjusting the pyrolysis rate, preferably by temperature control. The liquid level can alternatively or simultaneously be controlled by the introduction rate of fresh feed.

[0096] Maintaining a predetermined liquid level in a separation vessel can contribute to achieving efficient pyrolysis, 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 contribute to the system achieving an efficient and / or safe startup procedure.

[0097] 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:

[0098] - a heating device, preferably a heat exchanger, which is configured to receive the waste plastics and heat the waste plastics to a pyrolysis temperature;

[0099] - a separation vessel downstream of the heating device, wherein the separation vessel comprises:

[0100] - an inlet which is arranged to receive the gaseous and liquid plastic waste at pyrolysis temperature from the heating device,

[0101] - an upper outlet for the gaseous material to leave; and

[0102] - a liquid level measurement system for determining the liquid level in the separation vessel, the liquid level measurement system comprising one, more or all of the devices selected from the group of radar measurement, radioactive measurement, temperature measurement, mass measurement and differential pressure measurement.

[0103] In one aspect of the present invention, there is provided a method for pyrolyzing plastic materials, the method comprising the steps of:

[0104] - heating the plastic materials to a pyrolysis temperature to provide a fluid stream comprising liquid hydrocarbons and gaseous hydrocarbons, and solid carbon particles of at least partially pyrolyzed materials;

[0105] - transferring the fluid stream to a gas-liquid separation vessel, wherein the gaseous and liquid materials are preferably separated under the action of gravity;

[0106] - releasing the gaseous material from the separation vessel for processing the gaseous material into hydrocarbon products;

[0107] - accumulating the liquid comprising entrained solid carbon particles in the bottom portion of the separation vessel and subjecting the liquid to further pyrolysis, with further formation of solid carbon particles;

[0108] - settling the solid carbon particles to the bottom portion of the separation vessel; and

[0109] - removing at least a portion of the mixture of hydrocarbons and solid carbon particles from the bottom portion of the separation vessel,

[0110] And recycle the mixture of the hydrocarbon and the solid carbon particles to the bottom portion.

[0111] Recycling of the mixture can help provide a more efficient discharge of the particle-rich liquid and thus provide a more robust and lower maintenance cost apparatus and process, reducing or preventing gelling, coalescence, agglomeration or the like in the dense material. This can help prevent blockage of the separation vessel and can assist in carbon removal in the process.

[0112] Preferably, in the method, in the step of withdrawing and recycling the mixture of the hydrocarbon and the solid carbon particles, the hydrocarbon and the solid carbon particles are withdrawn from the bottom of the separation vessel and recycled and injected into the separation vessel at a location above the bottom withdrawal point and below the liquid level in the separation vessel, preferably below the outlet for withdrawing a portion of the accumulated liquid material having a lower solid particle concentration from the separation vessel. This recycles the high-concentration material into the low-concentration zone, thus helping to reduce blockage.

[0113] Preferably, the properties of the withdrawn material can be measured, such as properties indicating coke, charcoal or solid particle concentration or particle size. This can be accomplished by density analysis, turbidity analysis, viscosity analysis, spectrometer analysis, radioactivity analysis and / or ultrasonic analysis.

[0114] Preferably, the withdrawn liquid containing solids can be heated before being returned to the separation vessel.

[0115] In one aspect, 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:

[0116] - Heating means, preferably a heat exchanger, for receiving the waste plastics and heating the waste plastics to the pyrolysis temperature;

[0117] - A separation vessel downstream of the heating means, wherein the separation means comprises:

[0118] - An inlet arranged to receive the gaseous and liquid plastic waste at the pyrolysis temperature from the heating means,

[0119] - An upper outlet for the gaseous material to leave;

[0120] - A carbon outlet at the base of the separation vessel for withdrawing a mixture of hydrocarbon and solid carbon particles from the bottom portion of the separation vessel;

[0121] - One or more recycle nozzles positioned in the bottom portion of the separation vessel for injecting at least a portion of the withdrawn mixture into the separation vessel.

[0122] To determine the characteristics of the removed liquid, the device may include sampling points or sampling stations for determining the characteristics of the removed mixture, preferably characteristics indicating the concentration or size of solid carbon particles in the mixture, preferably including at least one sensor selected from density sensors, turbidity sensors, flow sensors, spectrometers, radioactive sensors, and / or ultrasonic sensors. Monitoring can help control the process and determine when cleaning or maintenance is required.

[0123] In various aspects, it can be useful to reduce or limit carbon formation in a container in which pyrolysis gas is separated from a liquid, partially pyrolyzed plastic material. In this regard, it can be useful to reduce, limit, or avoid direct heating of such a container, such as heating the container wall or incorporating a heating element (such as a heating coil) within such a container. The preferred separation container of the present invention is not heated, for example, no jacket heater or internal heating element is provided. The introduced molten waste plastic stream may already be provided at the pyrolysis temperature and no additional heating in the separation container is required. In some preferred embodiments, the liquid, partially pyrolyzed plastic material collected in the separation container is controllably preferably removed from the separation container by a pump and preferably reheated to the pyrolysis temperature in a heat exchanger, and then optionally returned to the separation container together with fresh feed. Thus, the long-chain hydrocarbons in the removed liquid can undergo further pyrolysis and decompose into short-chain hydrocarbons, and finally leave via a fractionator.

[0124] The waste plastic feedstock of the present invention may preferably include polyethylene and / or polypropylene plastics. Preferably, the sum of polyethylene and polypropylene in the feedstock accounts for at least 50% by weight of the feedstock, more preferably at least 60% by weight, still 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 of the feedstock are polyethylene or polypropylene.

[0125] The feedstock may also include polyvinyl chloride plastic. However, the content of PVC may preferably be limited to less than 10% by weight, preferably less than 5% by weight. PVC may be present in an amount greater than 1% by weight, more preferably greater than 5% by weight. The effective absence of PVC in the feedstock may be preferred.

[0126] The feedstock may also include polyethylene terephthalate plastic, preferably greater than 3% by weight of polyethylene terephthalate plastic, more preferably greater than 4% by weight. The feedstock preferably includes at most 20% by weight of PET plastic. Preferably, the content of polyethylene terephthalate plastic is at most 10% by weight, more preferably 5% by weight.

[0127] The feedstock may include up to 100 wt% of polystyrene plastic. In an embodiment, the feedstock may include at least 5 wt%, more preferably 20 wt%, and even more preferably 50 wt% of polystyrene.

[0128] Depending on factors such as feedstock composition and operating pressure, the pyrolysis temperature can vary within a limited range. Preferably, the plastic material is heated to 360 °C or higher, about 390 °C or higher, more preferably about 400 °C or higher, up to a pyrolysis temperature of about 450 °C, but higher temperatures up to about 500 °C or about 550 °C can be achieved. Plastic pyrolysis can start at about 360 °C, and such temperatures can thus also be considered. However, at temperatures of about 390 °C or above, pyrolysis is more significant, which can allow for a more economically attractive process.

[0129] As used herein, the term "pyrolysis zone" refers to a zone where the material being processed by the process or system (e.g., waste plastic or its derivatives generated by pyrolysis in the process or system) is at the pyrolysis temperature, e.g., at 360 °C or above, more preferably at 390 °C or above, still more preferably at or above 400 °C. The pyrolysis zone is preferably those zones in the process or system where the processed material is at about 360 °C to about 550 °C, more preferably about 390 °C to about 500 °C, still more preferably about 400 °C to about 500 °C. The process and system can include pyrolysis zones with different activities. For example, there can be: a primary pyrolysis zone where most of the pyrolysis occurs, which is preferably at a temperature above 390 °C; and a secondary pyrolysis zone where the temperature is above 360 °C but below 390 °C. The pyrolysis zone is the zone in the system, process, or equipment where pyrolysis occurs or the conditions for pyrolysis are created.

[0130] As is commonly understood, pyrolysis is carried out in the absence of oxygen, most preferably in an inert atmosphere. Nitrogen can provide an inert atmosphere. Before startup, the system can be purged with nitrogen to at least provide an initial inert atmosphere.

[0131] The gas phase may preferably consist of pyrolysis gas that is substantially free of oxygen and optionally includes nitrogen.

[0132] The operating pressure of the separation vessel is preferably higher than ambient pressure to ensure that ambient air does not enter the system. The pressure can be 1 absolute bar to 5 absolute bar, 1 absolute bar to 3 absolute bar, 1 absolute bar to 2 absolute bar, or 1 absolute bar to 1.5 absolute bar, or 1 absolute bar to 1.05 absolute bar.

[0133] The present invention preferably produces one or more hydrocarbon products, preferably where the hydrocarbon products include one or more of the following: 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, wax, asphalt or mixtures thereof. The hydrocarbon products can be saturated, unsaturated, straight-chain, cyclic or aromatic. Additional products can include non-condensable gases including methane, ethane, ethylene and / or other small molecules. The products can be a feedstock source for a steam cracker for plastic manufacturing.

[0134] As differently mentioned, the term "non-condensable" or "non-condensable gas" refers to a hydrocarbon fraction that is too volatile in the distillation section to be condensed and will likely, preferably, leave the process as a gas. It is generally believed that non-condensable hydrocarbons in the pyrolysis process have from about 1 to about 7 carbon atoms. Non-condensables can include saturated, unsaturated, straight-chain, cyclic and / or aromatic hydrocarbons.

[0135] As differently mentioned, the term "light hydrocarbon" or "LHC" refers to a hydrocarbon fraction that is condensable in the process and can thus be obtained as a liquid, but contains short-chain molecules. It is generally believed that LHC in the pyrolysis process has from about 3 to about 8 carbon atoms, possibly having a small fraction of C2 molecules and / or C10 molecules. LHC can include saturated, unsaturated, straight-chain, cyclic and / or aromatic hydrocarbons.

[0136] As differently mentioned, the term "heavy hydrocarbon" or "HHC" refers to a hydrocarbon fraction that is condensable in the process and can thus be obtained as a liquid, having a generally longer chain composition than LHC. It is generally believed that HHC in the pyrolysis process has at least about 7 carbon atoms (possibly having a small fraction of C6 molecules), preferably up to about 35 carbon atoms. A preferred range can include a low-range product of about 7 to about 20 carbon atoms, possibly having a small fraction of C6 and / or C21 molecules. For the low-range product, the end boiling point of HHC can be about 430 °C. Another preferred range can include a medium-range product of about 8 to about 28 carbon atoms. For the medium-range product, the end boiling point of HHC can be about 450 °C. Another preferred range can include a high-range product of about 10 to about 35 carbon atoms. For the high-range product, the end boiling point of HHC can be about 550 °C. HHC can include saturated, unsaturated, straight-chain, cyclic and / or aromatic hydrocarbons.

[0137] Those skilled in the petrochemical industry should understand that in the distillation process, the boundaries between non-condensables, LHC and HHC may vary to some extent. The overlap and / or variation can depend especially on the selected temperature, pressure and flow settings, and the product specifications can be adjusted to suit the desired product quality. Description of the Drawings

[0138] The features and advantages of the present invention will be understood with reference to the following drawings, in which:

[0139] Figure 1 Components for cracking long-chain hydrocarbons are shown;

[0140] Figure 2 Is shown in more detail Figure 1 Embodiments of the separation vessel, partial condenser and reboiler;

[0141] Figure 3 Embodiments of the separation vessel are shown;

[0142] Figure 4 Is shown Figure 3 A side elevation view of the separation vessel of;

[0143] Figure 5 Is shown Figure 3 A side elevation view of the separation vessel of;

[0144] Figure 6 Is shown Figure 3 A side elevation view of the separation vessel of;

[0145] Figure 7 Is shown Figure 3 A cross-section of the separation vessel of;

[0146] Figure 8 Is shown Figure 3 A top view of the separation vessel of;

[0147] Figure 9 Is shown Figure 3 The bottom surface of the separation vessel of;

[0148] Figure 10 Is shown Figure 3 A partial enlarged view of the lower part of the separation vessel of;

[0149] Figure 11 A reheating recovery circuit for the separation vessel is schematically shown;

[0150] Figure 12 Is shown Figure 3 A partial enlarged view of the lower part of the separation vessel of;

[0151] Figure 13 A lower part of the separation vessel provided with an internal liquid withdrawal outlet is schematically shown;

[0152] Figure 14 A lower part of the separation vessel provided with an internal liquid withdrawal outlet is schematically shown;

[0153] Figure 15Schematically shows the lower part of a separation vessel provided with an internal liquid take-off outlet and an internal shield;

[0154] Figure 16 Schematically shows the liquid flow pattern around Figure 15 the shield.

[0155] Figure 17 Schematically shows the lower part of a separation vessel provided with a carbon and / or pitch circulation circuit;

[0156] Figure 18 Schematically shows a separation vessel provided with a liquid level temperature sensor;

[0157] Figure 19 Schematically shows a separation vessel provided with a liquid level radiation sensor; and

[0158] Figure 20 Schematically shows a separation vessel provided with a load sensor. Detailed Description

[0159] It should be understood that, for simplicity and clarity of illustration, where appropriate, reference numerals may be reused in the various figures to indicate corresponding or similar elements or steps. Additionally, numerous specific details are set forth 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. Further, this specification is not to be considered as limiting the scope of the embodiments described herein in any way, but rather as merely illustrating the manner of implementation of the various embodiments described herein. The following is a description of certain embodiments of the present invention, which description is given by way of example only and with reference to the drawings.

[0160] Figure 1 Shows a device including a heating device 11 and a separation vessel 12. The heating device 11 is in communication with the separation vessel 12 to feed a fluid (liquid and gas) into the separation vessel 12. More specifically, the heating device 11 feeds a fluid in a gaseous and liquid state containing (partially) cracked hydrocarbons into the separation vessel 12 at a pyrolysis temperature.

[0161] In some embodiments, the feed device 7 is arranged to fill the heating device 11 with a material containing long-chain hydrocarbons, such as the waste plastics discussed. In some embodiments, the feed device includes an actuator 8 for heating and / or conveying the material containing long-chain hydrocarbons. In some embodiments, the actuator is an auger 8, which is arranged to convey the material containing long-chain hydrocarbons and preferably also to heat the material. In some embodiments, the auger 8 moves the material, and the internal friction in the material causes the material to heat up and melt. In additional embodiments, the feed device 7 includes a heating device, such as an electric heater or a heating device filled with a heating medium such as hot oil. The feed device 7 drives the material containing long-chain hydrocarbons into the heating device 11.

[0162] A substantial portion of the solid particulates are generated by the pyrolysis reaction and the resulting carbon or coke particles (common in pyrolysis). Due to impurities in the initial plastic feed stream of the process, there may be other particulates, such as metal particles and other debris, including for example organic matter. In the illustrated embodiment, four heating zones are shown. Each of the heating zones 1, 2, 3, 4 can be a heat exchanger, preferably a shell and tube heat exchanger. The heating zones 1, 2, 3, 4 provide a flow path for the plastic material containing long-chain hydrocarbons. The heating zones 1, 2, 3, 4 continuously or gradually increase the exposure temperature along the flow path. Preferably, the heating is carried out gradually to reduce or avoid carbon formation due to excessive temperature differences.

[0163] The heating device 11 heats the plastic material feedstock and melts it, thereby raising its temperature to the pyrolysis temperature. Pyrolysis can start in any of the heating zones 1, 2, 3, 4, with most of the pyrolysis in the heating zone preferably occurring in heating zone 4, which is the hottest of the four heating zones. 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 be in the range of 360 °C to 550 °C, more preferably 390 °C to 450 °C.

[0164] The molten, partially pyrolyzed plastic material leaves heating zone 4 at the pyrolysis temperature and enters the separation vessel 12 via the separation vessel inlet 14.

[0165] In the separation vessel 12, the incoming pyrolysis gas and liquid are separated. The gas will rise and flow out to the partial condenser 5, while the liquid will drop to the bottom of the separation vessel 12.

[0166] A recycle loop 26 is provided to remove the liquid partially pyrolyzed plastic material collected in the separation vessel 12 by means of a pump 27. The removed liquid is reheated to the pyrolysis temperature by a heat exchanger 28 and then returned to the separation vessel 12, in the case shown, together with the fresh feed. This recycle loop 26 increases the residence time of the long-chain hydrocarbons at the pyrolysis temperature, causing them to undergo further pyrolysis and decompose into short-chain hydrocarbons, which eventually leave via the fractionator 5.

[0167] The recycle loop 26 is provided for reheating and reintroducing heat into the separation vessel 12 such that the separation vessel 12 is maintained at the pyrolysis temperature. The heat is carried into the separation vessel 12 by the incoming reheated material stream provided by the recycle loop 26.

[0168] In the preferred embodiment shown, the separation vessel 12 is not heated, the term "not heated" meaning that the separation vessel 12 is not heated by any heat source other than the heat carried by the incoming heated material (e.g., heated material entering the inner volume of the separation means from a heating means such as heating device 11 or another heating means that may be provided above or within the recycle or return loop).

[0169] It has been found useful to avoid providing heating means above or within the separation vessel, as found in some earlier attempts. This can help reduce carbon formation in the separation vessel 12 and reduce or avoid the need for special agitation means. For example, in earlier attempts it has been found that internal heaters such as heating coils can cause carbonization of the pyrolyzed material at the surface of the heating element. This carbon can represent a loss of product and can accumulate on the heating element, which requires shutdown for cleaning and maintenance. This may also be the case in vessels of the cracking reactor type, where the vessel walls are heated to bring the processed material to or maintain it at the pyrolysis temperature. Carbonization may occur at the inner surface of the cracking reactor walls, leading to the need for complex mixing, cleaning, and shutdown. Nevertheless, in some embodiments or aspects of the present invention, the use of direct heating of the separation vessel, for example via a jacket or an internal heat exchanger or heating coils, is not excluded in use, and such use may be employed to supply all or part of the heat demand to the pyrolysis zone.

[0170] In the preferred embodiment shown, the separation vessel 12 is not provided with an agitator, such as a stirrer or auger. Without wishing to be bound by theory, it is thought that incorporating an auger or similar agitation means in the separation vessel to agitate the liquid may be disadvantageous as it introduces complexity; forms surface areas on which carbon / carbon can accumulate, thus reducing efficiency and requiring maintenance; and may disrupt the flow pattern imparted by the injection or material. Optionally, however, an agitator may be provided inside the separation vessel 12, or the agitator is not excluded from some embodiments and aspects, as may be useful for improving mixing inside the separation vessel 12.

[0171] Figure 2 The combination of the separation vessel 12, the partial condenser 5 and the reboiler 16 is shown more clearly therein.

[0172] At the moment of entering the separation vessel 12 via the inlet 14, since the plastic material is at the pyrolysis temperature, it is undergoing pyrolysis. The cracking of the plastic material results in the formation of a series of substances with a wide range of boiling points. The plastic material leaving the heating device 11 and entering the separation vessel 12 via the inlet 14 contains at least both gaseous and liquid components, where the liquid component contains at least partially cracked plastic material and may consist essentially of partially cracked plastic material. The liquid component may also contain molten, uncracked plastic material. The plastic material leaving the heating device 11 and entering the separation vessel 12 via the inlet 14 may additionally contain sludge and other solid debris, such as sand, aluminum or other metal particles.

[0173] The shown separation vessel 12 is elongated and arranged substantially vertically. Non-vertical arrangements, such as inclined or horizontal arrangements, are also conceivable. The pyrolyzed gaseous material rises in the separation vessel 12, while the liquid (partially) pyrolyzed material falls under the action of gravity. In this way, the gaseous and liquid materials are separated in the separation vessel 12 and thus separated.

[0174] The gaseous hydrocarbon material rising in the separation vessel 12 is discharged via the upper outlet 132 and transferred via the pipeline 6 to the partial condenser 5. The partial condenser 5 is remote from the separation vessel 12 and is located downstream of the separation vessel 12. The partial condenser is in fluid communication with the separation vessel 12 via the pipeline 6. The pipeline 6 is a gas pipeline for transporting gas to the partial condenser. Liquid is not transferred to the pipeline 6.

[0175] The partial condenser 5 is arranged and / or configured to remove heavy fractions (lower higher point fraction) from the exiting gas before the exiting gas is further transferred to the full distillation or condenser section of the equipment and process. In the partial condenser 5, the gas is cooled, as discussed below. As the gas is cooled, the heavier fractions condense and can be collected, while the lighter fractions remain gaseous and are transferred via a pipeline to the reboiler 16.

[0176] The partial condenser 5 is preferably provided with a packed tower 28 having (optional) random packing material, such as rings, for example Raschig rings, which increases the contact surface area between the gas and the liquid condensing in the partial condenser. As is known in the condensation process, this can assist effective condensation by providing a larger solid surface area for the condensing gas.

[0177] The 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 the cooling element 29 is controlled to cause the condensation of long-chain hydrocarbons (e.g., longer than C22), and the condensed material falls by gravity to the lower part of the partial condenser 5. The cooling element 29 is preferably downstream of the packed column 28.

[0178] As an alternative or additionally, selective condensation can be achieved by a cooling jacket (not shown) acting as a cooling element, or the partial condenser can be an external (total reflux) condenser.

[0179] The uncondensed gas (C1-C20 / C22, possibly up to C35) in the packed column 28 or the cooling element 29 is discharged via the upper outlet of the partial condenser and transferred via line 30 to a downstream distillation unit of the type commonly known in the petrochemical field for distillation purposes (e.g., as used for the distillation of crude oil or mineral oil fractions).

[0180] 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 extracted as an intermediate distillate, while the gaseous fraction can be extracted as a light boiler. The hydrocarbon products from the distillation unit can include butane, propane, kerosene, diesel, fuel oil; light distillates such as LPG, gasoline, naphtha or mixtures thereof; intermediate distillates such as kerosene, jet fuel, diesel or mixtures thereof; heavy distillates and residues such as fuel oil, lubricating oil, paraffin wax, wax, asphalt or mixtures thereof; or any mixture thereof. The hydrocarbon products can be saturated, unsaturated, straight-chain, cyclic or aromatic. Additional products can include non-condensable gases including methane, ethane, ethylene and / or other small molecules. The products can be a source of feedstock for steam crackers in plastic manufacturing.

[0181] The hydrocarbons condensed in the partial condenser 5 (e.g., containing ≥C22 chains, possibly containing a small fraction of <C22 carbon chains) are collected as a liquid 31 at the bottom of the partial condenser 5.

[0182] The liquid level at the bottom of the partial condenser is controlled by one or more liquid level control sensors and can be discharged batchwise or continuously. The liquid level control in the partial condenser 5 can be achieved continuously by a flow control valve.

[0183] The condensed liquid 31 in the partial condenser is preferably discharged via the lower outlet 32 of the partial condenser and transferred via line 33 controlled by an optional valve 34 to the reboiler 16. The valve 34 can be either a on-off valve or a control valve.

[0184] The condensed liquid 31 is collected in the reboiler 16, where it is reheated by the heater 13, preferably an internal heating element or an internal heat exchanger. The reboiler heater 13 can be heated electrically, with hot oil, or with other types of heating media. The condensed liquid in the reboiler 16 is heated to a temperature higher than the temperature of the partial condenser. External heating elements or external heat exchangers are also conceivable.

[0185] In this way, light hydrocarbon fractions that may inevitably be carried along with the partial condenser condensate can be evaporated or boiled and sent to the distillation equipment via the upper outlet 15 of the reheater vessel. These light hydrocarbon fractions can then be included in the distillation products. This can increase the product yield compared to systems or processes where the partially condensed material is returned directly to the pyrolysis zone. This can also be considered more preferable than returning the light hydrocarbons to the pyrolysis zone, where the light hydrocarbons can further crack or form relatively useless heat emissions as they are cycled and heated to evaporate again and then re-condense.

[0186] The reboiler 16 is preferably included as part of the distillation section and is in fluid communication with the gas added via the upper outlet 15 of the reheater vessel.

[0187] The liquid 35 that is collected in the reboiler and not distilled by evaporation through the upper outlet 15 of the reheater vessel can be pumped back to the separation vessel 12 via the pump 10 through the line 9, where optional further heating is carried out before entering the separation vessel 12. In this way, the liquid can be further pyrolyzed into useful products lighter than the products condensed in the partial condenser 5. For example, the liquid is returned to the separation vessel 12 and / or the pyrolysis zone and cracked until their chain length is reduced to C20 to C22 or shorter chain lengths. Thus, the product yield can be increased, and / or the ratio of light products to heavy products can be made more in line with customer requirements.

[0188] Alternatively, the liquid that is collected in the reboiler and not distilled by evaporation through the upper outlet 15 of the reheater vessel can be collected as a useful product. For example, the product can be paraffin and is transported to the collection container via the valve 21.

[0189] The partial condenser coil 29 typically operates at a temperature between 220°C and 380°C, while the reboiler typically operates at a temperature between 340°C and 400°C. These temperatures are both lower than the operating temperatures of a typical cracking reactor, which are 390°C and 450°C.

[0190] The liquid pyrolysis material present in the separation vessel 12 is preferably continuously circulated by an external pump 27. As the liquid is circulated, it can be reheated to the pyrolysis temperature by the heat exchanger 28 for further cracking.

[0191] Preferably, a distillation column (not shown) is provided at the top of the upper outlet 15 of the reheater vessel. The distillation column may be provided with a certain area which is designed as a packed column, and optionally, packing is contained in this area, or preferably, above this area, intermediate trays are provided on which the liquid fraction (diesel product or HHC) can be collected and the liquid fraction can be discharged. The HHC (e.g., diesel) product discharged from the distillation unit is preferably cooled by a heat exchanger, and a part of this cooled diesel product can be recycled to the distillation unit via a recovery streamline in order to set the optimum temperature conditions.

[0192] Possible settings leading to low-range product compositions may include:

[0193] - The temperature at the outlet of the partial condenser is about 290 °C;

[0194] - The temperature of the reboiler (liquid) is about 360 °C,

[0195] - The temperature at the outlet of the upper distillation column is about 80 °C,

[0196] - The temperature of the LHC condenser for the condensed LHC liquid is about 42 °C

[0197] - The final boiling point of HHC: 430 °C

[0198] Possible settings leading to medium-range product compositions may include:

[0199] - The temperature at the outlet of the partial condenser is about 320 °C;

[0200] - The temperature of the reboiler (liquid) is about 380 °C,

[0201] - The temperature at the outlet of the upper distillation column is about 100 °C,

[0202] - The temperature of the LHC condenser for the condensed LHC liquid is about 42 °C

[0203] - The final boiling point of HHC: 450 °C

[0204] Possible settings leading to high-range product compositions may include:

[0205] - The temperature at the outlet of the partial condenser is about 330 °C;

[0206] - The temperature of the reboiler (liquid) is about 380 °C,

[0207] - The temperature at the outlet of the upper distillation column is about 120 °C,

[0208] - The temperature of the LHC condenser for the condensed LHC liquid is about 55 °C

[0209] - The final boiling point of HHC: 550 °C

[0210] Reference Figures 3 to 9 provides a more detailed illustration of the separation vessel 12 in a system that can be used for Figure 1 and Figure 2 .

[0211] The separation vessel 12 in a plastic-to-chemicals (PTC) facility typically has multiple functions. Such functions can include any one, several, or all of the following functions.

[0212] The separation vessel can serve to assist in separating the gas phase, liquid phase, and solid particle phase present in an incoming partially pyrolyzed plastic material stream. As discussed, the plastic material entering the separation vessel from the heating device 11 is at a temperature at which it is undergoing pyrolysis but has not yet been fully pyrolyzed. Thus, the plastic material leaving the heating device 11 and entering the separation vessel 12 via the inlet 14 contains at least gaseous components and (partially pyrolyzed) liquid components, which will be separated for different further processing. The incoming material stream can also include solid particulate material. A significant portion of the solid particulates is produced by the pyrolysis reaction and the resulting carbon or coke particles (common in pyrolysis). Due to impurities in the initial plastic feed stream of the process, other particulates may be present, such as metal particles and other debris.

[0213] In the separation vessel, the gaseous material will separate from the liquid and solid materials due to gravity and be conveyed upward towards the exit point. The liquid and solid phases will be conveyed downward and collected in the separation vessel 12.

[0214] According to one aspect of the present invention, the separation efficiency and quality can be achieved by implementing various velocity patterns for the fluid flow in the separator 12.

[0215] The separation vessel 12 can serve to provide a residence time for the pyrolysis of the plastic material in the pyrolysis zone (i.e., in the zone where the temperature is high enough to cause pyrolysis). The plastic material can be retained within the separator 12 for a period of time and thus be pyrolyzed, and the liquid plastic material can also be removed, reheated, and returned to the separation vessel 12 for separation and / or further pyrolysis.

[0216] The separation vessel 12 can serve to mix fresh incoming liquid plastic material from the heater 11 and recycled partially pyrolyzed plastic material from heaters and / or reboilers outside the separation vessel 12, for example.

[0217] The separation vessel 12 can serve to control the characteristics and quality of the product stream by controlling the temperature, residence time, holding volume, and / or pressure.

[0218] The separation vessel 12 can be used to separate solid particles (e.g., coke, carbon particles or other debris) from a large amount of pyrolysis liquid. This can be achieved by one or both of the advantageous shape of the separation vessel 12 or the flow pattern of the material flow within the separation vessel 12. The solid particles can be removed as pitch.

[0219] Advantageously, as part of a continuous pyrolysis process, the separator 12 can be used to allow the removal of solid particles, coke, carbon, pitch, debris. That is, when pyrolysis continues within the separation vessel 12, it may be possible to remove pitch, coke, carbon, debris containing solid particles from the separation vessel.

[0220] The separation vessel 12 can be used as a container for holding (partially) pyrolyzed liquid plastic material in a liquid state (temporarily), and thus maintain a certain volume of (partially) pyrolyzed liquid plastic material in the system. This can advantageously simplify the (re)start operation, for example because the system pump can be primed from this volume of liquid at startup, and / or provide NPSH (Net Positive Suction Head) for the pump handling the liquid within the separation vessel 12.

[0221] Reference Figures 3 to 9 shows the separation vessel in detail.

[0222] The shown separation vessel 12 is provided with a plurality of injection points and discharge points.

[0223] A fresh feed injection point 121 is provided at the side wall of the separator 12 for receiving the fresh feed of plastic material that leaves the heating device 11 and enters the separation vessel 12 through the inlet 14 in the fresh feed injection point 121.

[0224] A reflux feed injection point 122 is provided at the side wall of the separator. The reflux of the reheated partially pyrolyzed plastic material can return through the reflux feed injection point after being reheated in the recycle reheating loop 26.

[0225] Preferably, a reboiler reflux injection point 124 is provided at the top of the separation vessel 12 for injecting the liquid 35 (e.g., paraffin) collected in the reboiler 16 and pumped back to the separation vessel 12 via the pipeline 9. The liquid 35 collected in the reboiler 16 preferably consists of paraffin and / or long-chain hydrocarbons with a boiling point higher than about 400 °C.

[0226] The reboiler reflux injection point 124 is preferably positioned above the liquid level in the separation vessel 12, and most preferably at the top of the separation vessel 12. This can help prevent fouling of the reboiler reflux injection point 124 by carbon / coke, which may occur if the reboiler reflux injection point 124 is below the liquid level in the separation vessel 12.

[0227] The reboiler liquid 35 is injected into the separation vessel 12 via line 9, preferably semi - continuously and most preferably continuously. This is considered to advantageously provide a stable process for pyrolysis in the separation vessel 12, with a predictable and stable heat distribution and / or a predictable and stable flow stream within the separation vessel 12. This is considered to have an advantage compared to batch delivery.

[0228] The liquid 35 returned from the reboiler 16 to the separation vessel 12 can be further cracked in the separation vessel 12 to provide more of the desired short - chain products.

[0229] A nitrogen injection point 125 is provided for injecting a nitrogen layer above the pyrolysis reaction. The nitrogen injection point 125 is preferably located at the top of the separation vessel 12. Via a nitrogen injection point nozzle, a preferably (semi) - continuous nitrogen flow is supplied to the upper region of the separation vessel 12. The flow rate can be about 1 to 20 liters per hour, more preferably 2 to 10 liters per hour. Providing nitrogen can help maintain the pyrolysis system, the separation vessel 12, at atmospheric pressure or preferably above atmospheric pressure. Overpressure (above ambient pressure) can help exclude oxygen intrusion and thus reduce the risk of unwanted air intrusion, which can adversely affect product quality, especially the quality of HHC products.

[0230] An internal, preferably substantially central, liquid outlet 128 is provided within the hollow body of the separation vessel, through which the liquid, partially pyrolyzed plastic material can be removed (e.g., under the influence of a pump) and transferred to the reheating circuit 26.

[0231] A side liquid outlet 127 is provided, through which the liquid of the partially pyrolyzed plastic material can be removed from the substantially peripheral region of the separation vessel (e.g., under the influence of a pump) and transferred to the reheating circuit 26.

[0232] A carbon outlet 124 is provided at the base of the separator 12 for discharging the carbon - containing pitch or other solids that settle to the bottom of the separator 12.

[0233] A pressure equalization line 123 is provided. The pressure equalization line can help achieve pressure equalization during the pitch / carbon discharge from the base of the separation vessel 12.

[0234] Asphalt recirculation nozzles 130, 131 can also be provided. The pitch or high - solids - content material at the base of the separation vessel 12 can be recirculated to reduce or prevent gelling, coalescence, coagulation, or similar phenomena in the dense material. This can help prevent blockage of the carbon outlet 129.

[0235] A gas outlet 132 is provided at the top of the separation vessel 12 shown, through which the (partially) cracked gaseous material formed during the pyrolysis reaction can be transferred via line 6 to the condenser 5 and then further processed in the form of optional distillation, use as fuel, and / or other treatments.

[0236] It is generally advantageous for all inlets and outlets of the separation vessel 12 to be flush with the inner surface of the separation vessel 12, if possible, i.e., to project substantially not into the vessel. This can help reduce or prevent fouling within the separation vessel and / or interference with the flow pattern.

[0237] In pyrolysis use, a fresh feed stream is transferred from the heating device 11 into the separation vessel 12 through the separation vessel inlet 14 at the fresh feed injection point 121. The incoming fresh feed contains a gas phase and a liquid phase generated by melting and cracking that has already occurred in the heating device 11. Once inside the separation vessel 12, the incoming cracked gas and liquid separate. The gas rises to the gas outlet 132 and exits via line 6 to reach the condenser 5, and the liquid (with any entrained solid particles) accumulates in the separation vessel 12, where the solid particles sink to the bottom part through the liquid phase. The separation vessel 12 is filled to a predetermined level, where the liquid phase is in its lower part and the gas phase separates upward to the upper part of the vessel, in which the gas phase is mainly present.

[0238] In the embodiment shown, the fresh feed of the gas / liquid mixture is shown to be injected tangentially into the separation vessel 12. Then, the gas phase and the liquid phase separate upward and downward, respectively, within the inner volume of the separation vessel 12.

[0239] The tangential introduction or injection of the fresh feed can at least partially provide a vortex or swirling flow pattern for the incoming gas / liquid stream. This can help with efficient phase separation of the flow, where the denser liquid is centrifugally driven to the periphery while the gas rises upward.

[0240] The liquid and entrained solids are collected at the bottom part of the separation vessel 12. The collected liquid has not been fully cracked in terms of all the desired product characteristics and is still too heavy for distillation. During the conversion of plastics to chemicals, the liquid is therefore subjected to a further residence time under pyrolysis conditions to further crack the polymer chains.

[0241] As previously discussed herein, it has been found useful to avoid providing a heating device above or within the separation vessel 12, as can be found in some earlier attempts, for example, heating the walls of the pyrolysis reactor or providing heating elements or heat exchangers inside the pyrolysis reactor.

[0242] To introduce heat into the separation vessel 12 and thus maintain the pyrolysis temperature therein, the liquid collected in the lower part of the separation vessel 12 is removed from the separation vessel 12 and the liquid is passed through a recycle heating circuit 26 where the liquid fraction of the pyrolyzed plastic material is reheated to the pyrolysis temperature by a heat exchanger 28 and then returned to the separation vessel 12. In some embodiments, the reheated plastic material may be combined with the fresh feed before being injected into the separation vessel 12. In Figures 3 to 10 the embodiment shown, for the recycle stream, a recycle feed injection point 122 is provided in the side wall of the separation vessel 12 separate from the fresh feed injection point 121, through which the recycle of the reheated partially pyrolyzed plastic material returns after being reheated in the recycle heating circuit 26. The recycle feed stream brings heat into the separation vessel 12, thus maintaining the pyrolysis conditions within the separation vessel 12 and at the same time providing additional residence time for the plastic material that will still be further pyrolyzed until the resulting short-chain hydrocarbons can be processed into the desired products by distillation.

[0243] The liquid level in the separation vessel 12 can be controlled, for example, by balancing the fresh feed input and the gaseous pyrolysis material output. The output rate of the gaseous material can be mainly controlled via the pyrolysis rate, i.e., by controlling the temperature in the separation vessel 12. This temperature can be controlled by the circulation rate of the liquid via the recycle heating circuit 26 and / or the temperature of the heater in the recycle heating circuit 26.

[0244] The equilibrium liquid level can also be controlled by controlling the rate of the fresh feed input, by increasing or decreasing the feed of fresh molten plastic from the heater 11.

[0245] The equilibrium liquid level can also be controlled by controlling the rate of removal or purging of carbon from the separation vessel 12, by increasing or decreasing the removal of the carbon-containing material in the base of the separation vessel 12.

[0246] The pressure in the separation vessel 12 is preferably maintained above atmospheric pressure, preferably slightly above atmospheric pressure, such as, for example, in the range of 50 to 100 mbarg. The pressure in the separation vessel 12 can be controlled to affect the product yield, and it is contemplated that the separation vessel 12 can be operated at a higher pressure or at a pressure below atmospheric pressure.

[0247] Operating the separation vessel at a higher pressure, such as at a pressure of 100 mbarg or higher, preferably 200 mbarg or higher, more preferably 300 mbarg or higher, can help produce a lighter product with a lower final boiling point, or a greater proportion of the lighter product. Higher pressures above 5 barg or more can be employed. Without wishing to be bound by theory, it is believed that the higher pressure inhibits the evaporation of hydrocarbon chains, and longer chain hydrocarbons are more susceptible to this effect. Hydrocarbons, especially longer chain hydrocarbons, are less likely to evaporate and thus remain in the pyrolysis zone and are further cracked into lower boiling point hydrocarbons.

[0248] Operating the separation vessel at a lower pressure, such as below atmospheric pressure, such as below 0 mbarg, preferably below 10 mbarg, more preferably below 30 mbarg, more preferably below 50 mbarg, can help increase the fraction with a high boiling point, such as paraffin. Lower pressures above 0 absolute bar (vacuum reactor) can also be employed. Without wishing to be bound by theory, it is believed that at lower pressures, longer chain hydrocarbons will be more likely to evaporate and thus leave the pyrolysis zone before they are further cracked into lower boiling point substances.

[0249] The temperature and residence time inside the separation vessel 12 are interrelated. By balancing these two parameters, the preferred liquid volume in the separation vessel 12 can be achieved. For example, a higher temperature can result in faster cracking and gasification rates, thus reducing the residence time of the material in the system.

[0250] The temperature of the liquid in the separation vessel 12 is controlled to be the pyrolysis temperature. Preferably, the temperature of the bulk liquid in the separation 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 be in the range of 360 °C to 550 °C, more preferably 390 °C to 450 °C, more preferably about 400 °C to about 450 °C. The higher temperature increases the rate of the cracking reaction.

[0251] The residence time in the pyrolysis zone of the equipment and operation is preferably about 10 minutes to about 12 hours, more preferably about 20 minutes to about 6 hours, more preferably about 30 minutes to about 3 hours. The residence time is a measure of the time that a certain volume of material is present in the pyrolysis zone. The residence time of the system can be calculated as volume (m 3 ) / flow rate (m 3 / s). The residence time can be reported as the average residence time or average transit time, i.e., the average residence time of all the material leaving the control volume at time t.

[0252] The temperature and production rate can vary during pyrolysis and can be adjusted according to the changes in the feedstock plastic. This allows the process to be adapted to different plastic types, especially those with different cracking temperatures. The operation can be adjusted to crack a homogeneous feedstock or a heterogeneous feedstock having two or more plastic types.

[0253] As discussed, the separation vessel 12 is provided with a fresh feed injection point 121 and a reflux feed injection point 122. It has been found that the fresh feed injection point 121 and the reflux feed injection point can have a significant impact on the flow behavior of the fluid inside the separation vessel 12.

[0254] One or preferably both of the fresh feed injection point 121 or the reflux feed injection point 122 can be arranged to inject the gas / liquid feed substantially tangentially into the separation vessel 12, preferably along or across the inner wall of the separation vessel 12, preferably in the circumferential direction. The injection points 121, 122 preferably inject the feed into the separation vessel below the liquid level of the liquid in the separation vessel 12, thereby forming a rotational, swirling or vortex flow pattern in the liquid. One or more of the injection points 121, 122 can alternatively be positioned to inject the feed into the separation vessel above the liquid level of the liquid in the separation vessel 12, but this is less preferred.

[0255] By making the introduction discussed in the gas / liquid zone below the collected liquid, a swirling effect can be obtained. Advantageously, this does not require an auger or similar agitation device to drive the bulk of the collected liquid into swirling rotation.

[0256] This swirling effect can advantageously improve one or more of the following: the settling of solids inside the separation vessel 12, especially dense particles (denser than the liquid); the distribution of the heat of the incoming feed to the material already in the separation vessel 12; the separation of gas and liquid; providing a central zone in the bulk of the collected liquid having a relatively low concentration of solid particles, such as carbon particles, from which the liquid can flow out through an internal, preferably substantially central, liquid outlet 128 and be transferred to the reheating circuit 26. This can help reduce or prevent the accumulation of blockages in the reheating circuit 26, the pump 27, the heat exchanger 28, and / or the reflux feed injection point 122.

[0257] The intensity of the vortex, swirling effect can be controlled by controlling or changing the inlet velocity at the fresh feed injection point 121 and / or the reflux feed injection point 122 (e.g., by changing the pump capacity, a higher recirculation flow rate or a greater mass injection), and by the ratio of the two inlet velocities or the relative inflow rate.

[0258] The inlet velocity can be increased by narrowing the inlet nozzles at the injection points. For example, the fresh feed inlet nozzle can be reduced from an inner tube diameter of about 8 cm to about 6 cm, and the recycle feed inlet nozzle can be reduced from an inner tube diameter of about 15 cm to about 8 cm. Figure 9 The narrowing of the nozzles is shown in Figure 9 .

[0259] The velocity at the fresh feed injection point 121 and / or the recycle feed injection point 122 may also be increased due to the generation of pyrolysis gas in the heater 11 and the reheating circuit 26, both of which include a pyrolysis temperature zone. When the gas expands into the separation vessel 12 at a relatively low pressure, the gas can accelerate to a high inlet velocity, thus contributing to the generation of a swirling effect.

[0260] The swirling effect can also be controlled by the ratio of the flow rate and / or velocity between the fresh feed injection point 121 and the recycle feed injection point 122. Preferably, the ratio of the flow rate (liters per second) between the fresh feed injection point 121 and the recycle feed injection point 122 is preferably about 1:1 to 1:25, more preferably 1:20, still 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, still more preferably 1:15, and most preferably 1:8), and the operating ratio is adjusted during operation by, for example, controlling the frequency of the associated pump. The ratio of the feeds can be adjusted during operation to slow down or accelerate pyrolysis and to raise or lower the temperature in the separation vessel 12.

[0261] As can be optimized, additional or alternative injection nozzles can be provided at various circumferential positions to achieve a stable swirling effect.

[0262] The swirling effect can also be controlled by adjusting the surface roughness of the inner wall of the separation vessel 12. A lower surface roughness reduces the friction between the wall and the liquid, thus affecting the velocity of the liquid inside the vessel.

[0263] Although attempts have been made earlier to inject hot plastic melt in pyrolysis operations, the present invention can advantageously achieve improved separation, heat distribution, and / or reheating of the liquid pyrolysis material by introducing the injected gas / liquid mixture into the reaction vessel at a high velocity and / or at a defined basic tangential angle, and with different ratios between the injection nozzles, which causes the liquid to form a vortex.

[0264] Other earlier attempts to inject hot plastic melt in pyrolysis operations involved premixing the fresh feed and the recycle feed before entering the pyrolysis vessel. Without being bound by theory, the present invention is advantageous because the fresh feed can be introduced into the separation vessel more efficiently.

[0265] It has been determined that a heater 11 that causes pyrolysis prior to the separation vessel 12, such as achieving a pyrolysis temperature prior to injection into the separation vessel, can generate most of the gaseous material. It is considered that a more efficient process can be produced by releasing this gaseous material into the separation vessel 12 before mixing with the reflux feed. It is considered that this can help reduce or prevent further or excessive cracking of materials that are already gaseous.

[0266] In addition, without wishing to be bound by theory, it is considered that injecting the fresh feed and the recycled reheated stream separately into the separation vessel 12 can improve the efficiency and resilience of the system, particularly the pump in the recycle line 26. This may 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 will be less transmitted to the pump in the recycle stream 26. Instead, the relatively large volume of the separation vessel 12 can absorb or dissipate the pressure peaks associated with the fresh feed injection. For the pump in the recycle loop 26, this can help improve efficiency and reduce maintenance requirements.

[0267] Since pyrolysis (the thermal decomposition of materials at high temperature in an inert atmosphere) causes hydrocarbon cracking, coke (carbon) particles will form in the plastic material stream. Coke particles form in all pyrolysis zones of the process, including the heater 11, the separation vessel 12, and the recycle heater loop 26. The solid coke particles will tend to accumulate at the bottom of the separation vessel 12.

[0268] In addition to solid coke particles, other particulates, such as metal particles and other debris, may be present due to impurities in the initial plastic feed stream of the process. The feedstock may include inorganic materials, such as sand, glass, metal, or the like, preferably less than 10 wt% inorganic matter, more preferably less than 5 wt% inorganic matter.

[0269] It is advantageous to avoid or prevent excessive accumulation in the separation vessel 12 and the resulting blockage and / or efficiently remove solid particles to avoid product contamination.

[0270] As discussed regarding the tangential introduction of the fresh feed stream at the fresh feed injection point 121 and the recycled reheater stream at the reflux feed injection point 122, the injection affects the flow behavior inside the separation vessel 12. Tangential introduction through one, two, or more such nozzles can cause the fluid inside the cracking reaction vessel to form a swirl. Similar to a centrifuge, this swirl effect can advantageously improve the sedimentation of solids inside the separation vessel 12. This can advantageously provide the following effects: (centrifuged) solids are retained near the inner wall, and the sink is less suctioned by the pump than the light fluid.

[0271] Reference Figure 10, showing the lower conical part of the separation vessel 12, which conical part ends at the carbon emission point 129 at its lowest point.

[0272] Solid particles present in the pyrolysis liquid in the separation vessel 12 will tend to fall to the bottom of the separation vessel 12, thus settling and accumulating in the shown lower conical part 133, where the fluid flow has lower energy or remains relatively static at a low velocity.

[0273] When the solids reach the bottom of the separation vessel 12, the solids accumulate. The conical form at the bottom of the reactor helps to direct the settled solids towards the carbon emission section.

[0274] The lower conical part is particularly effective in combination with the settling of solid particles and the swirl effect, which drives the solids towards the inner wall of the separation vessel 12.

[0275] Without being bound by theory, it is considered that the inclination angle of the cone is very important for achieving effective settling of solids and avoiding blockages in the lower part of the separation vessel 12. Through research, it has been found that the inclination angle of the inner surface of the conical reactor should be inclined enough so that specific types of solid particles generated during pyrolysis do not adhere or accumulate on the inner wall of the separation vessel 12, while still allowing the solids to be transferred to a balance between the carbon outlet 129. A steeper angle may also result in an overly tall container and may lead to a limited volume in its lower part.

[0276] Without being bound by theory, it is considered that efficient pyrolysis can be achieved when the separation vessel 12 is provided with a conical lower part 133, where the internal opening angle α of the conical lower part of the separation vessel 12 is between about 30° and about 70°, more preferably between about 50° and about 70°, more preferably between about 55° and about 65°, and most preferably about 60°.

[0277] Additionally, without being bound by theory, it is considered that the separation of solid particles can be improved by restricting the surface roughness of the inner surface of the separation vessel 12, particularly its conical lower part 133. This can help to ensure effective and rapid settling, and also help to reduce the accumulation of blockages and prevent fouling and the accumulation of carbon solids.

[0278] Efficient pyrolysis can be achieved when the separation vessel 12 is provided with the following inner surface roughness in one or more of its inner surfaces: 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. Preferably, the inner surface of the conical lower part has this limited surface roughness.

[0279] Surface roughness is measured by the roughness average value (Ra), the unit of which is micrometer. The methods for measuring surface roughness are known to those skilled in the art. As an example, a roughness measuring instrument (perthometer) with a diamond probe can be used to measure surface roughness, and the roughness measuring instrument can display a surface with high unevenness. The methods for adjusting the surface roughness of a given material are also known to those skilled in the art and may include, but are not limited to, rough grinding, sawing, planing, shaping, drilling, or (chemical) milling.

[0280] In a previous proprietary attempt at an implementation of a plastic-to-chemicals plant, the container assisting in separating the pyrolysis liquid and gas was not equipped with a conical bottom but with an elliptical head. This alternative caused the bottom to be filled with contaminants and ultimately caused the reactor to be filled and blocked.

[0281] In a previous further proprietary attempt at an implementation of plastic-to-chemicals, the container assisting in separating the pyrolysis liquid was equipped with an inverted cone in the bottom of the container. The purpose of the inverted cone was to prevent the flow causing recirculation in the bottom of the container and to improve the sedimentation of solid particles. However, through research, it was determined that the blockage was caused by the inverted cone. For example, the peripheral opening around the inverted cone could be blocked by carbon, and carbon could accumulate on the inverted cone.

[0282] The prior art cannot achieve the (semi)-continuous discharge of solid particles such as carbon or the on-the-go discharge of particles such as carbon. In earlier pyrolysis attempts, it was necessary to shut down the pyrolysis for a given pyrolysis zone while removing (dry) carbon and char by grinding. The conical shape of the lower part 133 of the present invention and the swirling fluid flow in the separation container 12 can contribute to achieving efficient carbon removal with no or reduced shutdown requirements for pyrolysis. In particular, the combination of the conical shape of the lower part 133 and the swirling fluid flow is effective. Continuous char removal can be advantageous.

[0283] Reference Figure 11 , shows a schematic diagram of a separation container 12 provided with a recycle reheating circuit 26. The recycle reheating circuit 26 is the heat energy source of the separation container 12, preferably the main heat energy source of the separation container 12.

[0284] The liquid 140 (e.g., containing molten plastic and partially pyrolyzed hydrocarbons) in the lower part of the separation container 12 is pumped by a pump 27 to a heat exchanger 28, which is preferably a shell-and-tube heat exchanger. The heat exchanger 28 (re)heats the liquid to a temperature higher than the temperature of the liquid in the separation container 12. For example, about 410 °C to about 550 °C, more preferably about 410 °C to about 500 °C, still more preferably about 410 °C to about 450 °C.

[0285] Since pyrolysis occurs at these temperatures, the pumped liquid stream will generate pyrolysis gas and form part of the gas. To reduce the cavitation effect in pump 27, it is preferred to place the pump upstream of the heat exchanger 28 so that mainly a liquid phase is presented to pump 27.

[0286] (Re)heated fluid is returned to the separation vessel 12, thereby carrying thermal energy with the fluid and internally heating the separation vessel 12.

[0287] The fluid inside the heat exchanger 28 preferably has a minimum velocity to keep solid particles in suspension (prevent sedimentation) and reduce fouling of the heat exchanger surface due to carbon or char. At the inlet of the heat exchanger 28, the minimum velocity is preferably about 1 m / s, more preferably about 2 m / s. Due to gas formation increasing the volume and pressure, the velocity at the outlet of the heat exchanger 28 may be higher.

[0288] Then, the liquid-gas mixture is tangentially injected into the cracking reactor through the recycle reheating loop 26 at a high velocity (e.g., about 5 m / s, more preferably about 8 m / s, most preferably about 10 m / s). Tangential injection can advantageously help provide a vortex or swirling flow pattern in the fluid in the separation vessel 12. The liquid-gas mixture is injected below the liquid level 141. This can help generate the desired flow pattern in the gas / liquid zone in the separation vessel 12 and / or reduce or prevent blockage at the injection point.

[0289] The liquid 140 in the lower part of the separation vessel 12 is withdrawn from the separation vessel 12 via one or more outlets.

[0290] In the illustrated embodiment, two outlets are shown, one being an internal, preferably substantially central, liquid outlet 128 within the hollow body of the separation vessel and one being a side liquid outlet 127. The liquid outlets 128, 127 can be used individually or in combination.

[0291] Reference Figures 12 to 13 , the internal liquid outlet 128 is radially centered within the separation vessel 12, but non-centered or substantially radially centered positioning can also be employed. The opening of the internal liquid outlet 128 is positioned below the liquid level 141 in the separation vessel 12 so that the liquid can be withdrawn. The substantially central position of the opening of the internal liquid outlet 128 can be advantageous because in the swirling fluid flow in the separation vessel 12, the velocity in the radially central part is relatively low compared to the radially outer fluid flow, and solid particles tend to have been centrifuged to the circumferential periphery. Thus, as Figure 13 and Figure 14 shown by the arrow 145 in

[0292] InFigure 13 In it, the provided legend shows the liquid level 551, the liquid flow 552 with a lower tangential velocity near the inner surface, the solid particles (carbon particles) 553 in the liquid, the liquid flow direction 554, the liquid 555 transferred to the pump inlet, the high-speed liquid section 556 at the radially outer part of the container 12, and the bubbles 556. There may be a certain part or only a low concentration of bubbles 556 at this position.

[0293] The internal liquid outlet 128 opening is preferably placed above the liquid level or the settling zone of the conical bottom part 133 to reduce the suction of the solid particles settled in the conical bottom part 133.

[0294] The shown internal liquid outlet 128 opening is provided with a vertically oriented outlet 146, and the vertically oriented outlet includes a lower opening 147 and an upper opening 148, where the side wall extends between these openings. The lower part of the outlet 146 has a cylindrical form (with a circular or any other cross-section), while the upper part leading to the upper opening 148 has a frustoconical form. The outlet 146 can be formed to include a vertically oriented pipe with a reducer at its top. The upper opening 148 is smaller than the lower opening 147.

[0295] The positioning of the outlet 146 can advantageously assist in minimizing the amount of solid particles entrained by the liquid taken out via the outlet 146 and brought into the reheater recovery loop 26. This can help reduce the blockage of the reheater recovery loop 26, its pump 27, and its heater 28.

[0296] A larger part of the liquid will flow into the outlet via the lower opening 147, where the lower opening 147 is larger than the upper opening 146, that is to say, the upper opening 148 is reduced compared to the lower opening 147. The reduced size of the upper opening 148 can advantageously force the liquid to circulate to the top of the container. It can also help reduce the gas entrainment in the taken-out liquid flow brought to the recovery loop 26.

[0297] Due to the continuous pyrolysis in the separation container 12, pyrolysis gas is generated in the liquid body, resulting in a two-phase mixture containing bubbles 149 in the liquid. For various reasons, it is not desirable for the bubbles to be entrained by the flow into the recovery reheater loop 26. The gas can cause cavitation or other difficulties in the pump 27. The gas has been sufficiently cracked to leave the separation container 12 and reach the partial condenser, and preferably, the gas is not further heated and cracked into shorter chains. As Figure 14 As shown, the reduced-size upper opening 148 at the top of the outlet 146 reduces the suction from above the outlet, but allows the bubbles to pass through it and go to the top of the separation container 12. Since the gas can rise fast enough, the low flow rate to the outlet can also help reduce the gas suction.

[0298] The ratio of the opening area of the lower opening 147 to the opening area of the upper opening 148 is preferably greater than 1, preferably greater than 1.5, more preferably greater than 2, and even more preferably greater than 4.

[0299] Reference Figure 15 , the shroud 150 is shown positioned around the outlet 146 so as to enclose or define a volume around the outlet 146 within the separation vessel 12.

[0300] The shroud 150, shown in a preferred form as a pipe, preferably a cylindrical pipe or tube having an open upper end and a lower end, can advantageously assist in restricting entrainment of solid particles into the liquid withdrawn via the outlet 146.

[0301] The shroud 150 is preferably substantially concentric with the outlet 146, which outlet itself is preferably located at the radial center of the separation vessel 12.

[0302] The shroud 150 inside the separation vessel 12 is preferably at least partially immersed in the liquid body within the separation vessel 12. The shroud preferably defines a radially inner portion of the liquid volume having a certain concentration of solid particles, the concentration of which solid particles is lower than the concentration of solid particles in the radially outer volume of the liquid. This can be achieved because the solid particles in the separation vessel 12 will tend to be centrifuged to the circumferential periphery in the separation vessel 12. The solid particles will thus tend to sink radially outward from the shroud 150, and the shroud 150 can help restrict or prevent the radial intrusion of solid particles towards the outlet 146. Thus, as Figure 15 shown by the arrow 145 in, a liquid with a relatively low concentration of solid particles can be withdrawn at the opening of the internal liquid outlet 128 in the low kinetic energy zone (where the flow rate is lower than the flow rate outside the shroud 150) within the shroud 150.

[0303] The shroud 150 inside the separation vessel 12 is preferably completely immersed in the liquid body within the separation vessel 12. It is considered that the liquid can then easily escape from the top or from the bottom of the shroud 150, and this can help avoid the occurrence of dead zones or stagnant zones in the liquid.

[0304] Figure 16 The flow pattern of the liquid around the shroud 150 is shown in. The circulating flow will tend to centrifuge the solid particles radially outward, while the fluid within the shroud 150 is protected from being affected by the transfer or kinetic energy or solid particles.

[0305] The shroud 150 can partially or completely surround the liquid outlet point. The shroud can have a substantially solid wall or a porous wall with filter holes.

[0306] Preferably, one or more walls of the shroud 150 are substantially vertical, as this can help limit or avoid fouling due to solid materials. Generally, the walls are thin to minimize flow disruption and minimize horizontal surfaces.

[0307] Preferably, one or more walls of the shroud 150 are smooth to minimize or avoid fouling. Preferably, the surface roughness of one or more 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 6 μm, and even more preferably 4 μm.

[0308] Without wishing to be bound by theory, the shroud 150 can facilitate improving or maintaining the separation of liquid and solids within the separation vessel 12, which can result in reducing or preventing blockages in the components of the recuperator loop 26. It can also help increase the tolerance to high solid particle concentrations within the separation vessel 12, thereby reducing the total purge in the carbon dioxide outlet 129 and potentially resulting in a higher product yield.

[0309] As an alternative or supplement to the internal liquid outlet 128, the side liquid outlet 127 is substantially flush with the inner wall of the separation vessel 12. The side liquid outlet 127 is positioned below the liquid level 141 within the separation vessel 12 such that liquid can be withdrawn, and is preferably positioned above the liquid level or sedimentation zone of the conical bottom portion 133 to reduce the entrainment of solid particles sedimented in the conical bottom portion 133.

[0310] During operation, one or both of the internal liquid outlet 128 and the side liquid outlet 127 can be employed. When both are employed, the ratio of liquid withdrawal can be from 100:0 to 0:1000, 90:10 to 10:90, or preferably 60:40 to 40:60, preferably approximately 50:50.

[0311] Withdrawing liquid via the side liquid outlet 129 and / or the ratio of withdrawal between the outlets can advantageously affect the velocity and flow pattern within the separation vessel 12. In particular, the configuration of the side liquid outlet 129 being flush with the vessel wall can help provide an uninterrupted flow pattern within the vessel.

[0312] Withdrawing liquid via two or more liquid outlets (internal or side) can be advantageous due to the reduced pressure drop in the pump 27.

[0313] Reference Figure 17, as discussed, solid particles present or generated in the pyrolysis liquid in the separation vessel 12 will tend to fall to the bottom of the separation vessel 12, and thus settle and accumulate in the lower conical portion 133 shown, where the fluid flow has lower energy or remains relatively stationary at low velocities. The liquid containing a high concentration of solid particles can be discharged via the carbon emission point 129.

[0314] Through research, it has been determined that failures may occur when the liquid rich in carbon particles is discharged via the carbon emission point 129. Providing the asphalt circulation nozzles 130, 131 can help provide a more efficient discharge of the particle-rich liquid, and thus provide a more robust and lower maintenance cost equipment and process. The asphalt or high-solid content material at the base of the separation vessel 12 can be recycled via the asphalt circulation nozzles 130, 131 to reduce or prevent gelling, coalescence, coagulation or the like in the dense material. This can help prevent blockage of the carbon outlet 129.

[0315] The high-solid content liquid can be removed via the carbon emission point 129 and recycled via a pipeline for re-entry via the asphalt circulation nozzles 130, 131.

[0316] The high-solid content liquid can be reheated or cooled before returning to the separation vessel 12. For this purpose, a heater or a cooler can be provided. The temperature in the separation vessel 12 can be at least partially controlled or affected in this way.

[0317] During recycling, the high-solid content liquid can be sampled or monitored by one or more sensors to determine the solid particle concentration. This can help accurately determine the volume of the high-solid content liquid to be disposed of to avoid excessive accumulation of solid particles in the separation vessel 12. This can help provide efficient pyrolysis as the loss of hydrocarbon products in the purge stream is more limited and / or maintenance operations such as cleaning or unclogging are reduced.

[0318] A sampling point 557 can be provided in the return pipeline. The sensors can include density sensors, turbidity sensors, viscosity sensors, flow sensors, spectrometers, radioactive sensors, ultrasonic sensors or similar sensors.

[0319] In the case of an (temporary) shutdown, deceleration or startup procedure, as a way to maintain or provide heating and kinetic energy to the lower part of the separation vessel 12, the circulation of the asphalt or high-solid content material at the base of the separation vessel 12 can also be beneficial. This can reduce or prevent blockage at the base of the separation vessel 12 as the hydrocarbons remain liquid while the solids remain in suspension.

[0320] Reference Figures 18 to 20, the liquid level inside the separation vessel 12 can be measured in a variety of different ways. A number of alternatives are shown, but other alternatives can be considered. For accuracy, two or more or all of the discussed alternatives can be implemented.

[0321] Measuring the liquid level inside the separation vessel 12 is complex. Some sensors may malfunction due to fouling or deteriorate due to harsh conditions, and other sensors may become inaccurate due to foaming at the liquid surface, giving false readings.

[0322] A radar measuring device can be provided, preferably a guided wave radar gauge.

[0323] The guided wave radar gauge is placed inside the separation vessel 12. The guided wave radar level gauge is placed at the top of the separation vessel. The guided wave radar gauge can provide a wide operating range with good reliability. In particular, the rod-type guided wave radar is suitable for operating under foaming liquids, and the gauge operates independently of noise, pressure, temperature, and density changes. Additionally, the influence of fouling on the guided wave radar probe or the inner surface of the separation vessel on the measurement accuracy is minimal.

[0324] The guided wave radar gauge is used as a measuring device to control the liquid level in the reaction vessel.

[0325] In Figure 18 , a temperature-measuring liquid level sensor arrangement is shown, preferably a multi-point temperature-measuring sensor arrangement.

[0326] The multi-point temperature gauge is placed inside the cracking reactor. The multi-point temperature communicator 300 is preferably placed in the nozzle 301. The temperature sensing rod 302 is installed at the top of the container. The temperature measuring rod 302 is equipped with a series of individual temperature sensors spaced along the length of the rod 302, such as two or more, five or more, or about twelve or more. The liquid level can be evaluated based on the temperature difference between adjacent sensors on the rod 302. Through research and practice, it has been determined that the liquid phase is usually (although not always) a few degrees hotter than the gas phase, for example, the temperature difference between the gas phase and the liquid phase is 3°C to 6°C.

[0327] The accuracy of the temperature measurement will depend on the number of temperature sensors provided on the rod 302 and their spacing.

[0328] Another advantage of the temperature-based measurement of the liquid level is that information about the entire pyrolysis process in the separation vessel 12 can be obtained simultaneously, especially during startup or transient conditions. During startup, for example, the bottom of the container may remain colder than the liquid at higher levels in the container. This may be due to the greater density of the cold liquid. Multiple temperature feedbacks from the rod 302 can alert the operator to adverse conditions in the separation vessel 12.

[0329] InFigure 19 In it, an external radiation measurement device is shown, preferably an external gamma source liquid level measurement device. Figure 19 The legend in it shows radiation 560 and liquid level 561.

[0330] The shown separation vessel 12 is equipped with an external radioactive liquid level measurement device, which includes a radiation source 305 (preferably gamma or X-ray radiation) and a radiation detector 306. It has been found that radioactive liquid level measurement can still provide accurate liquid level measurement despite the dynamic processes and conditions (including foaming and potential fouling) in the pyrolysis zone. In particular, radioactive liquid level measurement does not require an internal probe or other internal sensors.

[0331] In Figure 20 it, a mass-based measurement is shown. The mass of the liquid can be determined based on the measured mass, and thus also the liquid level. A load cell 310 is arranged to measure the weight of the separation vessel 12. Two load cells 310 are arranged at the support of the reaction vessel.

[0332] As an alternative or supplementary measurement, the separation vessel can be equipped with differential pressure measurement. Based on the differential pressure measurement and the density of the liquid, the liquid level can be calculated. For example, this can be done in one of two ways. One way is to provide a pressure sensor at the bottom part of the separation vessel 12 and a pressure sensor at the top part of the separation vessel 12 (optionally in the gas phase). By combining the differential pressure determination with the density of the liquid, the liquid level can be obtained.

[0333] A further advantage of the described separation vessel is that a reliable, safe and simple startup can be achieved. The startup process can include the following steps. Add diesel or a similar heavy hydrocarbon liquid to the separation vessel 12 until a predetermined liquid level; circulate and heat the liquid via the reheating recovery loop 26 to reach a startup temperature higher than the ambient temperature; start supplying fresh feed to the separation vessel 12.

[0334] Starting with a higher boiling hydrocarbon, such as paraffin (boiling point > 370 °C), which may possibly be sourced from the reheater / reboiler 16, can be advantageous because the reheating recovery loop 26 can heat the liquid to a high temperature such that the startup liquid inside the separation vessel can reach a temperature close to pyrolysis, for example about 350 °C to 370 °C, before introducing fresh plastic raw material into the separation vessel 12.

[0335] Starting with a higher boiling hydrocarbon can also help protect the pump, which might otherwise suffer from cavitation if it includes components with too low boiling points.

[0336] All documents cited in the specific embodiments of the present invention are incorporated herein by reference in their relevant parts; the citation of any document does not constitute an admission that it is prior art with respect to the present invention. If any meaning or definition of a term in this written document conflicts with any meaning or definition of that term in a document incorporated by reference, the meaning or definition assigned to that term in this written document shall prevail.

[0337] Although specific embodiments of the present invention have been shown and described, it will be apparent to those skilled in the art that various other changes and modifications can be made without departing from the spirit and scope of the present invention. Accordingly, all such changes and modifications are intended to be covered by the appended claims within the scope of the present invention.

[0338] The following clauses relate to various aspects of the present invention.

[0339] Clause 0.1: A method for pyrolyzing a plastic material, the method comprising the steps of:

[0340] - Heating the plastic material to a pyrolysis temperature to provide a fluid stream comprising liquid hydrocarbons and gaseous hydrocarbons of at least partially pyrolyzed material;

[0341] - Injecting the fluid stream of liquid hydrocarbons and gaseous hydrocarbons into a gas-liquid separation vessel, wherein the gaseous material and the liquid material are preferably separated under the action of gravity;

[0342] - Releasing the gaseous material from the separation vessel for processing the gaseous material into hydrocarbon products;

[0343] - Accumulating the liquid in the bottom portion of the separation vessel and subjecting the liquid to further pyrolysis;

[0344] wherein the fluid stream of liquid hydrocarbons and gaseous hydrocarbons is injected to create a vortex or swirling fluid flow in the separation vessel.

[0345] Clause 0.2: The method according to clause 0.1, wherein the injection of the fluid stream is carried out below the liquid level of the accumulated liquid in the separation vessel.

[0346] Clause 0.3: The method according to any one of clauses 0.1 to 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 injected into the separation vessel.

[0347] Clause 0.4: The method according to any one of clauses 0.1 to 0.3, wherein injecting the fluid stream of liquid hydrocarbons and gaseous hydrocarbons into the gas-liquid separation vessel comprises injecting the fluid stream substantially tangentially to the inner surface of the separation vessel, preferably wherein the separation vessel has a substantially circular cross-section at least at the injection point.

[0348] Clause 0.5: The method as described in any one of Clauses 0.1 to 0.4, wherein the step of heating the plastic material to the pyrolysis temperature to provide a stream of pyrolysis gaseous hydrocarbons includes heating the plastic material to the pyrolysis temperature in one or more heat exchangers, preferably a plurality of heat exchangers arranged in series, so as to provide a stream of at least partially pyrolyzed gaseous material and liquid material.

[0349] Clause 0.6: The method as described in any one of Clauses 0.1 to 0.5, which further includes removing the accumulated liquid material from the separation container, reheating the liquid material to the pyrolysis temperature and returning the liquid material as a second fluid stream containing liquid hydrocarbons and gaseous hydrocarbons to the separation container.

[0350] Clause 0.7: The method as described in Clause 0.6, wherein the second fluid stream is injected separately into the gas-liquid separation container, and the gaseous material and the liquid material are separated.

[0351] Clause 0.8: The method as described in any one of Clauses 0.6 to 0.7, wherein the second fluid stream of liquid hydrocarbons and gaseous hydrocarbons is injected to generate or intensify the vortex or swirling fluid flow in the separation container.

[0352] Clause 0.9: The method as described in any one of Clauses 0.1 to 0.8, wherein pyrolysis causes solid carbon particles to be generated in the fluid stream, and the vortex or swirling fluid flow drives the solid carbon particles radially outward, preferably whereby the solid particles settle to the base of the method as described in any one of the foregoing clauses.

[0353] Clause 0.10: The method as described in any one of Clauses 0.1 to 0.9, which includes providing a plastic material feedstock, wherein the plastic material feedstock includes polyethylene and / or polypropylene plastics, preferably wherein the sum of polyethylene and polypropylene in the feedstock accounts for at least 50% by weight of the feedstock, more preferably at least 60% by weight.

[0354] Clause 0.11: The method as described in Clause 0.10, wherein the feedstock includes polyvinyl chloride plastic, preferably more than 1% by weight of polyvinyl chloride plastic, more preferably more than 5% by weight, or wherein the feedstock includes less than 5% by weight, more preferably less than 1% by weight of polyvinyl chloride plastic.

[0355] Clause 0.12: The method as described in any one of Clauses 10 to 11, wherein the feedstock includes polyethylene terephthalate plastic, preferably more than 3% by weight of polyethylene terephthalate plastic, more preferably more than 4% by weight, or wherein the feedstock includes less than 4% by weight of polyethylene terephthalate plastic, more preferably less than 3% by weight.

[0356] Clause 0.13: A method as described in any one of Clauses 10, 11 or 12, wherein the raw material comprises polystyrene plastic, preferably greater than 1% by weight of polystyrene plastic, more preferably greater than 5% by weight, or wherein the raw material comprises less than 20% by weight of polystyrene plastic, more preferably less than 5% by weight.

[0357] Clause 0.14: A method for producing hydrocarbon materials, which comprises the steps of any one of Clauses 0.1 to 0.13, and the following additional steps: distilling gaseous hydrocarbons in a distillation apparatus to obtain hydrocarbon products, preferably wherein the hydrocarbon products comprise butane, propane, kerosene, diesel oil, fuel oil; light distillates such as LPG, gasoline, naphtha or mixtures thereof; middle distillates such as kerosene, jet fuel, diesel oil or mixtures thereof; heavy distillates and residues such as fuel oil, lubricating oil, paraffin wax, wax, asphalt or mixtures thereof; or any mixtures thereof; saturated, unsaturated, straight-chain, cyclic or aromatic hydrocarbons; non-condensable gases including methane, ethane, ethylene and / or other small molecules; and mixtures thereof.

[0358] Clause 0.15: An apparatus for pyrolyzing waste plastics into one or more hydrocarbon products, preferably at least one or more liquid hydrocarbon products, the apparatus comprising:

[0359] - A heating device, preferably a heat exchanger, which is used to receive waste plastics and heat the waste plastics to a pyrolysis temperature;

[0360] - A separation container downstream of the heating device, wherein the separation device comprises:

[0361] - An inlet, which is arranged to receive gaseous and liquid plastic wastes at the pyrolysis temperature from the heating device,

[0362] - An upper outlet for gaseous materials to leave; and

[0363] - A lower outlet for liquid materials to leave;

[0364] wherein the inlet is arranged to inject gaseous and liquid plastic wastes from the heating device to generate a vortex or swirling fluid flow in the separation container.

[0365] Clause 0.16: The apparatus as described in Clause 0.15, wherein the heating device is configured to heat the waste plastics to a pyrolysis temperature of about 360 °C to about 550 °C, preferably about 390 °C to about 450 °C.

[0366] Clause 0.17: Equipment as described in Clause 0.15 or 0.16, wherein the inlet is arranged to inject gaseous and liquid plastic waste from a heating device tangentially to substantially the inner surface of a separation vessel, preferably wherein the separation vessel has a substantially circular cross-section at least at the injection point.

[0367] Clause 0.18: Equipment as described in any one of Clauses 0.15 to 0.17, wherein the heating device comprises one or more heat exchangers, preferably shell and tube heat exchangers, more preferably a plurality of heat exchangers arranged in series.

[0368] Clause 0.19: Equipment as described in any one of Clauses 0.15 to 0.18, wherein the separation vessel is elongated and arranged vertically to allow the gaseous and liquid materials from pyrolysis to separate under the action of gravity, with the gaseous materials from pyrolysis passing upward to an upper outlet and the liquid materials passing downward.

[0369] Clause 1.1: A method for pyrolyzing plastic materials, the method comprising the following steps:

[0370] - Heating the plastic material to a pyrolysis temperature to provide a fluid stream containing liquid hydrocarbons and gaseous hydrocarbons of at least partially pyrolyzed material;

[0371] - Transferring the fluid stream of liquid hydrocarbons and gaseous hydrocarbons to a gas-liquid separation vessel, wherein the gaseous and liquid materials are preferably separated under the action of gravity;

[0372] - Releasing the gaseous material from the separation vessel for processing the gaseous material into hydrocarbon products;

[0373] - Accumulating the liquid in the bottom portion of the separation vessel and subjecting the liquid to further pyrolysis;

[0374] - Removing a portion of the accumulated liquid material from the separation vessel, heating the removed liquid to the pyrolysis temperature and returning the removed liquid as a fluid stream containing liquid hydrocarbons and gaseous hydrocarbons to the separation vessel; wherein the accumulated liquid is removed via an outlet inside the separation vessel, preferably an outlet located substantially at the radial center within the separation vessel.

[0375] Clause 1.2: The method as described in 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 provided to the separation vessel.

[0376] Clause 1.3: The method as described in any one of Clauses 1.1 to 1.2, wherein pyrolysis causes solid carbon particles to be generated in the separation vessel, and the fluid in the separation vessel is controlled to provide a vortex or swirl to centrifuge the solid carbon particles radially outward.

[0377] Clause 1.4: The method as described in Clause 3, wherein the outlet for removing the accumulated liquid is positioned in the substantially central part of the vortex or swirl.

[0378] Clause 1.5: The method as described in any one of Clauses 1.1 to 1.4, wherein a shroud is provided to at least partially radially surround the liquid outlet, preferably wherein the shroud is partially or completely immersed in the accumulated liquid.

[0379] Clause 1.6: The method as described in Clause 1.5, wherein the shroud at least partially isolates the liquid outlet from the radially outer swirl or vortex in the separation container.

[0380] Clause 1.7: The method as described in any one of Clauses 1.1 to 1.6, wherein the outlet for the accumulated liquid comprises a vertically arranged cylinder, preferably having a circular cross-section, with an opening at its upper end and an opening at its lower end.

[0381] Clause 1.8: The method as described in Clause 7, wherein the opening at the upper end is smaller than the opening at the lower end.

[0382] Clause 1.9: The method as described in any one of Clauses 1.1 to 1.8, wherein a returned fluid stream is injected into the separation container to generate or strengthen the swirl or vortex fluid flow in the separation container.

[0383] Clause 1.10: The method as described in any one of Clauses 1.1 to 1.9, wherein the injection of the fluid stream is carried out below the liquid level of the accumulated liquid in the separation container.

[0384] Clause 1.11: The method as described in any one of Clauses 1.1 to 1.10, which includes providing a plastic material raw material, wherein the plastic material raw material comprises polyethylene and / or polypropylene plastic, preferably wherein the sum of polyethylene and polypropylene in the raw material accounts for at least 50% by weight of the raw material, more preferably at least 60% by weight.

[0385] Clause 1.12: The method as described in Clause 1.10, wherein the raw material comprises polyvinyl chloride plastic, preferably more than 1% by weight of polyvinyl chloride plastic, more preferably more than 5% by weight, or wherein the raw material comprises less than 5% by weight, more preferably less than 1% by weight of polyvinyl chloride plastic.

[0386] Clause 1.13: The method as described in Clause 1.10 or Clause 1.11, wherein the raw material comprises polyethylene terephthalate plastic, preferably more than 3% by weight of polyethylene terephthalate plastic, more preferably more than 4% by weight, or wherein the raw material comprises less than 4% by weight of polyethylene terephthalate plastic, more preferably less than 3% by weight.

[0387] Clause 1.14: A method as described in Clauses 1.10, 1.11 or 1.12, wherein the raw material comprises polystyrene plastic, preferably greater than 1% by weight of polystyrene plastic, more preferably greater than 5% by weight, or wherein the raw material comprises less than 20% by weight of polystyrene plastic, more preferably less than 5% by weight.

[0388] Clause 1.15: A method for producing hydrocarbon materials, which comprises the steps of any one of Clauses 1.1 to 1.14, and the following additional steps: distilling gaseous hydrocarbons in a distillation apparatus to obtain hydrocarbon products, preferably wherein the hydrocarbon products include butane, propane, kerosene, diesel oil, fuel oil; light distillates such as LPG, gasoline, naphtha or mixtures thereof; middle distillates such as kerosene, jet fuel, diesel oil or mixtures thereof; heavy distillates and residues such as fuel oil, lubricating oil, paraffin wax, wax, asphalt or mixtures thereof; or any mixtures thereof; saturated, unsaturated, straight-chain, cyclic or aromatic hydrocarbons; non-condensable gases including methane, ethane, ethylene and / or other small molecules; and mixtures thereof.

[0389] Clause 1.16: An apparatus for pyrolyzing waste plastics into one or more hydrocarbon products, preferably at least one or more liquid hydrocarbon products, the apparatus comprising:

[0390] - Heating means, preferably a heat exchanger, for receiving the waste plastics and heating the waste plastics to a pyrolysis temperature;

[0391] - A separation container downstream of the heating means, wherein the separation means comprises:

[0392] - An inlet arranged to receive gaseous and liquid plastic waste at pyrolysis temperature from the heating means,

[0393] - An upper outlet for the gaseous material to leave; and

[0394] - A lower outlet for the liquid material to leave;

[0395] wherein the lower outlet for the liquid material to leave is positioned inside the separation container, preferably at a substantially radial center.

[0396] Clause 1.17: The apparatus as described in Clause 1.16, wherein the heating means is configured to heat the waste plastics to a pyrolysis temperature of about 360 °C to about 550 °C, preferably about 390 °C to about 450 °C.

[0397] Clause 1.18: The 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 means substantially tangentially to the inner surface of the separation container, preferably wherein the separation container has a substantially circular cross-section at least at the injection point.

[0398] Clause 1.19: A device as described in any one of Clauses 1.16 to 1.18, wherein the separation container is elongated and vertically arranged to allow the gaseous and liquid materials resulting from pyrolysis to separate under the action of gravity, with the gaseous materials resulting from pyrolysis being transferred upwards to the upper outlet and the liquid materials being transferred downwards.

[0399] Clause 1.20: A device as described in any one of Clauses 1.16 to 1.19, wherein the liquid outlet is located below the operating liquid level of the separation container and is preferably submerged during use.

[0400] Clause 2.1: A device for pyrolyzing waste plastics into one or more hydrocarbon products, preferably at least one or more liquid hydrocarbon products, the device comprising:

[0401] - Heating means, preferably a heat exchanger, for receiving the waste plastics and heating the waste plastics to the pyrolysis temperature;

[0402] - A separation container downstream of the heating means, wherein the separation container comprises:

[0403] - An inlet arranged to receive the gaseous and liquid plastic waste at the pyrolysis temperature from the heating means,

[0404] - An upper outlet for the gaseous materials to leave; and

[0405] - A hollow body, the bottom part of which is substantially conical;

[0406] wherein the opening angle of the substantially conical bottom part is from about 30° to about 70°.

[0407] Clause 2.2: A device as described in Clause 2.1, wherein the opening angle is from about 50° to about 70°, preferably from about 55° to about 65°, more preferably about 60°.

[0408] Clause 2.3: A device as described in any one of Clauses 2.1 to 2.2, wherein the separation container has one or more inner walls, and the surface roughness of the inner walls is less than Ra 25 μm, preferably less than Ra 15 μm, more preferably less than Ra 12 μm, and even more preferably less than Ra 10 μm.

[0409] Clause 2.4: A device as described in any one of Clauses 2.1 to 2.3, wherein the inlet is configured to allow the material to enter the separation container tangentially.

[0410] Clause 2.5: A device as described in Clause 2.4, wherein the inlet is configured to allow the material to enter the separation container at a high enough speed to achieve a swirling or vortex motion of the material in the separation container.

[0411] Clause 2.6: The apparatus as described in any one of Clauses 2.1 to 2.5, wherein the bottom part of the separation vessel includes an outlet arranged to allow material to leave the separation vessel, preferably a carbon emission outlet.

[0412] Clause 2.7: The apparatus as described in any one of Clauses 2.1 to 2.6, wherein the system is configured to heat the material.

[0413] Clause 2.8: The apparatus as described in any one of Clauses 2.1 to 2.7, wherein the system is configured to allow the material that has left the separation vessel via the outlet to circulate back into the separation vessel via an inlet.

[0414] Clause 2.9: A method for pyrolyzing plastic material, the method comprising the steps of:

[0415] - Heating the plastic material to a pyrolysis temperature to provide a fluid stream comprising liquid hydrocarbons and gaseous hydrocarbons, and solid carbon particles, of at least partially pyrolyzed material;

[0416] - Transferring the fluid stream to a gas-liquid separation vessel, wherein the gaseous material and the liquid material are preferably separated under the action of gravity;

[0417] - Releasing the gaseous material from the separation vessel for processing the gaseous material into hydrocarbon products;

[0418] - Accumulating the liquid comprising entrained solid carbon particles in the bottom part of the separation vessel, and subjecting the liquid to further pyrolysis, with further generation of solid carbon particles;

[0419] - Settling the solid carbon particles to the bottom part of the separation vessel, wherein the bottom part is substantially conical, and the opening angle of the substantially conical bottom part is about 30° to about 70°;

[0420] And

[0421] - Removing at least a portion of the mixture of hydrocarbon and solid carbon particles from the bottom conical part.

[0422] Clause 2.10: The method as described in 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 provided to the separation vessel.

[0423] Clause 2.11: The method as described in Clause 2.9 or 2.10, wherein pyrolysis causes solid carbon particles to be generated in the separation vessel, and the fluid in the separation vessel is controlled to provide a vortex or swirl to centrifugally move the solid carbon particles radially outwards.

[0424] Clause 2.12: The method as described in any one of Clauses 2.9 to 2.11 is carried out by means of the apparatus as described in any one of Clauses 2.1 to 2.8.

[0425] Clause 2.13: A method for producing hydrocarbon materials, which includes the steps of any one of Clauses 2.9 to 2.12, and the following additional steps: distilling gaseous hydrocarbons in a distillation apparatus to obtain hydrocarbon products, preferably where the hydrocarbon products 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, wax, asphalt or mixtures thereof; or any mixture thereof; saturated, unsaturated, straight-chain, cyclic or aromatic hydrocarbons; non-condensable gases including methane, ethane, ethylene and / or other small molecules; and mixtures thereof.

[0426] Clause 3.1: A method for pyrolyzing plastic materials, the method including the following steps:

[0427] - Heating the plastic material to a pyrolysis temperature to provide a fluid stream containing liquid hydrocarbons and gaseous hydrocarbons of at least partially pyrolyzed material;

[0428] - Transferring the fluid stream of liquid hydrocarbons and gaseous hydrocarbons to a gas-liquid separation container, where the gaseous material and the liquid material are preferably separated under the action of gravity;

[0429] - Releasing the gaseous material from the separation container for processing the gaseous material into hydrocarbon products;

[0430] - Accumulating the liquid in the bottom part of the separation container and subjecting the liquid to further pyrolysis; and

[0431] - Determining the liquid level in the separation container by means of radar measurement, radioactive measurement, temperature measurement, mass measurement and / or pressure measurement.

[0432] Clause 3.2: The method as described in Clause 3.1, where the liquid level in the separation container is controlled by adjusting the pyrolysis rate, preferably by temperature control.

[0433] Clause 3.3: The method as described in any one of Clauses 3.1 to 3.2, where the liquid level in the separation container is controlled by the introduction rate of fresh feed.

[0434] Clause 3.4: The method as described in any one of Clauses 3.1 to 3.3, where the liquid level in the separation container is maintained at a predetermined level.

[0435] Clause 3.5: A method for producing hydrocarbon materials, which includes the steps of any one of Clauses 3.1 to 3.5, and the following additional steps: distilling gaseous hydrocarbons in a distillation device to obtain hydrocarbon products, preferably where the hydrocarbon products 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, wax, asphalt or mixtures thereof; or any mixtures thereof; saturated, unsaturated, straight-chain, cyclic or aromatic hydrocarbons; non-condensable gases including methane, ethane, ethylene and / or other small molecules; and mixtures thereof.

[0436] Clause 3.6: An apparatus for pyrolyzing waste plastics into one or more hydrocarbon products, preferably at least one or more liquid hydrocarbon products, the apparatus comprising:

[0437] - Heating means, preferably a heat exchanger, which is used to receive waste plastics and heat the waste plastics to the pyrolysis temperature;

[0438] - A separation container downstream of the heating means, where the separation container includes:

[0439] - An inlet, which is arranged to receive gaseous and liquid plastic waste at the pyrolysis temperature from the heating means,

[0440] - An upper outlet for gaseous materials to leave; and

[0441] - A liquid level measurement system, which is used to determine the liquid level in the separation container, and the liquid level measurement system includes one, multiple or all of the devices selected from the group of radar measurement, radioactive measurement, temperature measurement, mass measurement and differential pressure measurement.

[0442] Clause 3.7: The apparatus as described in Clause 3.6, where the liquid level inside the container is measured using at least two, preferably three devices.

[0443] Clause 3.8: The apparatus as described in Clause 3.6 or 3.7, where the liquid level inside the container is measured using devices selected from the group of guided wave radar measurement, external radioactive liquid level measurement, differential pressure measurement and multi-point temperature measurement.

[0444] Clause 3.9: The apparatus as described in any one of Clauses 3.6 to 3.8, where the system is configured to control the liquid level inside the container.

[0445] Clause 3.10: The apparatus as described in any one of Clauses 3.6 to 3.9, where the system is further configured to control the pressure inside the container.

[0446] Clause 3.11: The equipment as described in any one of Clauses 3.9 to 3.10, wherein the equipment controls the liquid level inside the container by controlling the input rate of the fresh feed material entering the separation container and / or controlling the output rate of the material leaving the container as gas, liquid or purge via the outlet.

[0447] Clause 3.12: The equipment as described in any one of Clauses 3.9 to 3.10, wherein the equipment controls the liquid level inside the separation container by controlling the inflow rate and / or temperature of the material inside the container.

[0448] Clause 4.1: A method for pyrolyzing plastic materials, the method comprising the following steps:

[0449] - Heating the plastic material to a pyrolysis temperature to provide a fluid stream comprising liquid hydrocarbons and gaseous hydrocarbons and solid carbon particles of at least partially pyrolyzed material;

[0450] - Transferring the fluid stream to a gas-liquid separation container, wherein the gaseous material and the liquid material are preferably separated under the action of gravity;

[0451] - Releasing the gaseous material from the separation container for processing the gaseous material into hydrocarbon products;

[0452] - Accumulating the liquid comprising entrained solid carbon particles in the bottom part of the separation container and subjecting the liquid to further pyrolysis, with further generation of solid carbon particles;

[0453] - Settling the solid carbon particles to the bottom part of the separation container; and

[0454] - Removing at least a portion of the mixture of hydrocarbons and solid carbon particles from the bottom part of the separation container,

[0455] and recycling the mixture of hydrocarbons and solid carbon particles to the bottom part.

[0456] Clause 4.2: The method as described in 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 injected into the separation container.

[0457] Clause 4.3: The method as described in any one of Clauses 4.1 to 4.2, wherein the fluid in the separation container is controlled to provide a vortex or swirling fluid stream to centrifugally move the solid carbon particles radially outward.

[0458] Clause 4.4: A method as described in any one of Clauses 4.1 to 4.3, wherein in the step of withdrawing and recycling the hydrocarbon and solid carbon particle mixture, the hydrocarbon and solid carbon particles are withdrawn from the bottom of the separation vessel and recycled and injected into the separation vessel at a location above the bottom withdrawal point and below the liquid level in the separation vessel, preferably below the outlet for withdrawing a portion of the accumulated liquid material having a lower solid particle concentration from the separation vessel.

[0459] Clause 4.5: A method according to any one of the preceding clauses, further comprising the step of determining the characteristics of the withdrawn hydrocarbon and solid carbon particle mixture, preferably the content of the mixture, more preferably the characteristics indicating the concentration or particle size of coke, carbon or solid particles.

[0460] Clause 4.6: A method as described in Clause 4.5, wherein the step of determining the content of the mixture comprises any one or more of density analysis, turbidity analysis, viscosity analysis, spectrometer analysis, radioactivity analysis and / or ultrasonic analysis.

[0461] Clause 4.7: A method as described in any one of Clauses 4.1 to 4.6, wherein the ratio of the withdrawn mixture to the returned mixture is determined based on the analysis of one or more characteristics of the mixture, optionally wherein a portion of the withdrawn mixture is discharged, more preferably purged, preferably wherein the one or more characteristics indicate the concentration or size of the solid carbon particles in the mixture.

[0462] Clause 4.8: A method as described in any one of Clauses 4.1 to 4.7, comprising the step of heating the mixture during recycling outside the separation vessel.

[0463] Clause 4.9: A method as described in any one of Clauses 4.1 to 4.8, comprising providing a plastic material feedstock, wherein the plastic material feedstock comprises polyethylene and / or polypropylene plastic, preferably wherein the sum of polyethylene and polypropylene in the feedstock accounts for at least 50% by weight of the feedstock, more preferably at least 60% by weight.

[0464] Clause 4.10: A method as described in Clause 4.9, wherein the feedstock comprises polyvinyl chloride plastic, preferably greater than 1% by weight of polyvinyl chloride plastic, more preferably greater than 5% by weight, or wherein the feedstock comprises less than 5% by weight, more preferably less than 1% by weight of polyvinyl chloride plastic.

[0465] Clause 4.11: A method as described in Clause 4.9 or Clause 4.10, wherein the raw material comprises polyethylene terephthalate plastic, preferably greater than 3% by weight of polyethylene terephthalate plastic, more preferably greater than 4% by weight, or wherein the raw material comprises less than 4% by weight of polyethylene terephthalate plastic, more preferably less than 3% by weight.

[0466] Clause 4.12: A method as described in Clause 4.10, 4.11 or 4.12, wherein the raw material comprises polystyrene plastic, preferably greater than 1% by weight of polystyrene plastic, more preferably greater than 5% by weight, or wherein the raw material comprises less than 20% by weight of polystyrene plastic, more preferably less than 5% by weight.

[0467] Clause 4.13: A method for producing hydrocarbon materials, which comprises the steps of any one of Clauses 4.1 to 4.12, and the following additional steps: distilling 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; middle distillates such as kerosene, jet fuel, diesel or mixtures thereof; heavy distillates and residues such as fuel oil, lubricating oil, paraffin wax, wax, asphalt or mixtures thereof; or any mixtures thereof; saturated, unsaturated, straight-chain, cyclic or aromatic hydrocarbons; non-condensable gases including methane, ethane, ethylene and / or other small molecules; and mixtures thereof.

[0468] Clause 4.14: An apparatus for pyrolyzing waste plastics into one or more hydrocarbon products, preferably at least one or more liquid hydrocarbon products, the apparatus comprising:

[0469] - Heating means, preferably a heat exchanger, for receiving waste plastics and heating the waste plastics to a pyrolysis temperature;

[0470] - A separation vessel downstream of the heating means, wherein the separation means comprises:

[0471] - An inlet arranged to receive gaseous and liquid plastic waste at pyrolysis temperature from the heating means,

[0472] - An upper outlet for gaseous materials to leave;

[0473] - A carbon outlet at the base of the separation vessel for removing a mixture of hydrocarbons and solid carbon particles from the bottom part of the separation vessel;

[0474] - One or more recirculation nozzles positioned in the bottom part of the separation vessel for injecting at least a portion of the removed mixture into the separation vessel.

[0475] Clause 4.15: The equipment as described in 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.

[0476] Clause 4.16: The equipment as described in any one of Clauses 4.14 to 4.15, which further includes a sampling point or a sampling station for determining the characteristics of the withdrawn mixture, preferably the characteristics indicating the concentration or size of the solid carbon particles in the mixture.

[0477] Clause 4.17: The equipment as described in Clause 4.16, which further includes at least one sensor selected from a density sensor, a turbidity sensor, a flow sensor, a spectrometer, a radioactive sensor, and / or an ultrasonic sensor.

[0478] Clause 4.18: The equipment as described in any one of Clauses 4.14 to 4.18, wherein the separation container is elongated and vertically arranged to allow the gaseous and liquid materials from pyrolysis to separate under the action of gravity, with the gaseous material from pyrolysis transferring upward to the upper outlet and the liquid material transferring downward.

Claims

1. A method for pyrolyzing plastic materials, the method comprising the steps of: - heating the plastic material to a pyrolysis temperature to provide a fluid stream comprising liquid hydrocarbons and gaseous hydrocarbons of at least partially pyrolyzed material; - transferring the fluid stream of the liquid hydrocarbons and gaseous hydrocarbons to a gas-liquid separation vessel, wherein the gaseous material and the liquid material are preferably separated under the action of gravity; - releasing the gaseous material from the separation vessel for processing the gaseous material into hydrocarbon products; - accumulating the liquid in the bottom portion of the separation vessel and subjecting the liquid to further pyrolysis; and - determining the liquid level in the separation vessel by radar measurement, radioactive measurement, temperature measurement, mass measurement and / or pressure measurement.

2. The method according to claim 1, wherein the liquid level in the separation vessel is controlled by adjusting the pyrolysis rate, preferably by temperature control.

3. The method according to any one of the preceding claims, wherein the liquid level in the separation vessel is controlled by the introduction rate of fresh feed.

4. The method according to any one of the preceding claims, wherein the liquid level in the separation vessel is maintained at a predetermined liquid level.

5. A method for producing hydrocarbon materials, the method comprising the steps of any one of claims 1 to 5, and the following additional steps: distilling the gaseous hydrocarbons in a distillation apparatus to obtain hydrocarbon products, preferably wherein the hydrocarbon products include butane, propane, kerosene, diesel oil, fuel oil; light distillates such as LPG, gasoline, naphtha or mixtures thereof; middle distillates such as kerosene, jet fuel, diesel oil or mixtures thereof; heavy distillates and residues such as fuel oil, lubricating oil, paraffin wax, wax, asphalt or mixtures thereof; or any mixtures thereof; saturated, unsaturated, straight-chain, cyclic or aromatic hydrocarbons; non-condensable gases including methane, ethane, ethylene and / or other small molecules; and mixtures thereof.

6. An apparatus for pyrolyzing waste plastics into one or more hydrocarbon products, preferably at least one or more liquid hydrocarbon products, the apparatus comprising: heating means, preferably a heat exchanger, for receiving waste plastics and heating the waste plastics to a pyrolysis temperature; a separation vessel downstream of the heating means, wherein the separation vessel comprises: an inlet arranged to receive gaseous and liquid plastic waste at pyrolysis temperature from the heating means, an upper outlet for the gaseous material to leave; and a liquid level measurement system for determining the liquid level in the separation vessel, the liquid level measurement system comprising one, more or all of the devices selected from the group consisting of radar measurement, radioactive measurement, temperature measurement, mass measurement and differential pressure measurement.

7. The apparatus according to claim 6, wherein the liquid level inside the vessel is measured using at least two, preferably three devices.

8. The apparatus according to claim 6 or 7, wherein the liquid level inside the vessel is measured using devices selected from the group consisting of guided wave radar measurement, external radioactive liquid level measurement, differential pressure measurement and multi-point temperature measurement.

9. The apparatus according to any one of claims 6 to 8, wherein the system is configured to control the liquid level inside the container.

10. The apparatus according to any one of claims 6 to 9, wherein the system is further configured to control the pressure inside the container.

11. The apparatus according to any one of claims 9 to 10, wherein the apparatus controls the liquid level inside the container by controlling the input rate of fresh feed material entering the separation container and / or the output rate of material leaving the container as gas, liquid or purge via the outlet.

12. The apparatus according to any one of claims 9 to 10, wherein the apparatus controls the liquid level inside the separation container by controlling the inflow rate and / or temperature of the material inside the container.

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