Process for pyrolyzing substantially plastic materials having non-constant composition, associated reactors, equipment and resulting products - Patents.com

Abstract

The present invention relates to the treatment of plastic materials, such treatment being for reuse and valorization in a chemical recycling process for the reuse of substantially plastic materials, which are otherwise destined for disposal. In particular, the present invention relates to a process for pyrolysis of substantially plastic materials to obtain at least liquid hydrocarbons, said hydrocarbons being in a liquid state at 25° C., the method comprising the steps of: (a) Feeding a substantially plastic material (optionally already in a molten and / or preheated state) into a reactor for pyrolysis; (b) subjecting the material in the pyrolysis reactor to a temperature of between 330°C and 580°C (substantially in the absence of oxygen) and a pressure between atmospheric and 13 bar(a); (c) maintaining the material in the pyrolysis reactor at a temperature between 330° C. and 580° C. for a time sufficient to produce at least one gaseous effluent in the pyrolysis reactor; (d) adjusting the pressure in the pyrolysis reactor in relation to characteristic parameters defined by the composition of the substantially plastic material and / or characteristic parameters defined by the products of the pyrolysis process, while maintaining said pressure at a value between atmospheric pressure and 13 bar(a); (e) A step of partially or totally concentrating said gaseous effluent so as to form at least one fluid comprising liquid hydrocarbons (which are in a liquid state at 25° C.), said fluid being quantitatively at least 10% by weight based on the weight of the substantially plastic material provided. (f) characterizing the process by low delay in pressure adjustment in step (d).

Description

[Technical field]

[0001] The present invention relates to the treatment (or processing) of substantially plastic materials (or plastic substances materials or plastic materials), such treatment being for use in a chemical recycling process (or chemical recycling process) for the re-use (or reuse) and valorisation (or valorisation or valorisation) of substantially plastic materials which are otherwise destined for disposal.

[0002] In particular, the present invention relates to a process (or step or treatment or method) for processing a substantially plastic material (or plastics material or plastic substance material or plastic material) of indefinite composition (or changing composition or variable composition), an associated reactor (or reactor) and the resulting product (or article or product).

[0003] Advantageously, the invention may be used to process substantially plastic materials (or plastics materials or plastic substances materials or plastic materials) that have been previously treated (or pre-treated) in a sorting plant (or sorting factory or sorting plant) in which several plastic materials (or plastics materials or plastic substances materials or plastic materials) are identified (or recognized or identified or identified) and separated as individual polymers (or separation).

[0004] In this way, the fractions (or portions) that can be recovered as a single type of polymer can be reused as is, and only the parts (or components) that cannot be recovered as individual polymers undergo pyrolysis (or pyrolysis). After pyrolysis, hydrocarbons are produced. These hydrocarbons can be subjected to further processing (e.g. steam cracking) to produce monomers. The monomers can then be polymerized again to form new (or virgin) plastics.

[0005] Compared to the simple recovery or selective extraction of individual polymers in a sorting plant, the cycle of regenerating plastics by pyrolysis is obviously more expensive and more complicated, but it can result in a total recovery of the discarded plastics, and also has substantial advantages from an environmental point of view. [Background technology]

[0006] (State of the art) There are many publications and patent applications relating to the process of pyrolysis (or pyrolysis) of plastics (or plastic substances or plastics). However, very few studies have addressed the influence (or effects) of pressure.

[0007] In fact, the processes (or steps or treatments or methods) of the prior art relate to both processes (or steps or treatments or methods) under pressure and processes (or steps or treatments or methods) under reduced pressure, and no particular preference is given to one over the other in terms of operating (or operational) conditions.

[0008] For example, ES2389799 discloses a process for the production of diesel fuel (or diesel oil) (C13-C40). Such a process includes two stages under pressure (1-15 bar(a) (absolute)). The first stage is thermal, while the second stage is catalytic in the presence of hydrogen. The feed material is preferably of polyolefin origin, i.e. it is beyond the scope of the present invention to concern polymers which can be recycled simply by sorting. Polystyrene may be included, but preferably the content of other plastics (eg, PVC and PET) is less than 10%.

[0009] In contrast, a substantial portion of the prior art (e.g., WO2013187788, WO0231082 and EP2184334) suggests pyrolysis to be carried out at reduced pressure (pressure below atmospheric pressure).

[0010] For example, WO2013187788 (DAGAS SP ZOO, Poland) discloses a method for pyrolysis of plastics and / or rubber and / or organic waste, which comprises subjecting the waste to a pyrolysis reactor at 200-850° C. in the absence of air and separating the resulting products, and is characterized in that the process is continuously operated under reduced pressure of 0.1-0.9 atm. The plastic (or plastic material or plastic) provided in the examples is a mixture of polythene and polypropylene, although in example 1 20% polyamide is also provided. In addition to the charge (or packing) to be pyrolyzed, the reactor also contains a composition comprising water, an aliphatic alcohol, carbamide (or a derivative thereof) and monoacetylferrocene. Liquid hydrocarbons are produced, but not in significant amounts (40% of the feed in Example 1).

[0011] This prior art therefore demonstrates the advantages of operating the pyrolysis of plastic materials (most of which are polyolefins) at subatmospheric pressures. The reaction conditions vary widely, both with regard to parameters (temperature and residence time) as well as with regard to the type of reactor and any catalyst, and also with regard to the products obtained. Summary of the Invention [Problem to be solved by the invention]

[0012] From a review of the prior art, it is clear that there are many pyrolysis processes (or steps or treatments or methods) carried out at subatmospheric or superatmospheric pressures. However, there is no general technique that makes it possible to establish whether it is advantageous to manage a process (or step or treatment or method) of pyrolysis of complex polymer mixtures at atmospheric pressure, subatmospheric pressure (reduced pressure), or superatmospheric pressure (i.e., higher than atmospheric pressure). Often, the information available is subject to significant change and, in some cases, may be contradictory and represent completely different information. Furthermore, the identified documents do not provide any information on how to set the operating pressure of the pyrolysis system according to the quality of the polymer fed or the quality of the product obtained. In addition to this, the feed material is often relatively pure, being mostly polyethylene or a polyethylene-polypropylene blend. Furthermore, there is no case of a feed material whose composition is not constant, and in any case, it is not known how to manage changes in composition and the effect that this has on the process and resulting product.

[0013] The substantially plastic material remaining after the process of selection and extraction of the individual polymers is given its highly variable composition (and therefore inconstant nature) and is composed of a plurality of plastic and non-plastic materials.

[0014] Additionally, the pyrolysis process requires that the plastics fed to the process be preselected to reduce the amount of difficult-to-handle plastic materials (e.g., PVC, PET, cellulose, polystyrene) and non-plastic materials. Instead, polyolefins (specifically, polyethylene and polypropylene) are preferred. However, the majority of the polyolefins present in the substantially plastic material are generally separated in a selection process and then recycled as such, without pyrolysis. Therefore, with pyrolysis, there is a particular interest in processing the fraction remaining after selection, i.e. that which is at least used by the pyrolysis processes known in the art and which contains, in addition to a certain amount of polyolefins, a significant amount of other plastics and a smaller proportion of non-plastic materials.

[0015] Therefore, for the reasons set forth above, there is a need to identify processes (or steps or treatments or methods) that can overcome the limitations of the known art. [Means for solving the problem]

[0016] Summary of the Invention The Applicant has surprisingly found that by adjusting the reaction conditions, in particular the pressure, depending on the composition of the material to be treated, a plastic material having a non-constant composition can be successfully subjected to a process of pyrolysis. Accordingly, the applicant has developed the following process (or step or process or method). A process (or step or treatment or method) for pyrolysis of a substantially plastic material (or plastics material or plastic substance material or plastic material), preferably a continuous or semi-continuous process (or step or treatment or method) for obtaining at least liquid hydrocarbons, such hydrocarbons being in a liquid state at 25°C, by subjecting the substantially plastic material (or plastics material or plastic substance material or plastic material) (also having a non-constant composition and, if necessary, containing significant amounts of constituents that are normally considered undesirable) to a specific pyrolysis process (or step or treatment or method).

[0017] The process comprises a step of feeding the material to a pyrolysis reactor at a temperature between 330°C and 580°C and a pressure between atmospheric pressure and 13 bar(a) (absolute) in the substantial absence of oxygen, and further comprising a step of adjusting the pressure during the pyrolysis step in response to the composition comprising the substantially plastic material and / or the product of the pyrolysis process, wherein such pressure adjustment is preferably characterized by a low latency. Furthermore, the pyrolysis process is preferably characterized in that the substantially plastic material has a non-constant composition.

[0018] One of the advantages of the process disclosed in this invention, when combined with a pre-selection process, is that it allows for the recycling of plastics an infinite number of times ("closed loop recycling"), i.e. such materials can be used and then regenerated several times without losing their properties during the recycling process.

[0019] A further advantage of the process disclosed in the present invention is the ability of the process to process substantially plastic materials, such as vinyl polymers (polyethylene and polypropylene), polyvinyl aromatic polymers, such as polystyrene (PS) and related materials, non-vinyl polymers, such as polyethylene terephthalate (PET) and oxygen-rich polymers, such as cellulose and PET itself. In this case, there are no problems with fouling or blocking in any of the processes, and the liquid hydrocarbons, which are liquid at 25° C., are of high quality.

[0020] A further advantage of the process disclosed in the present invention is the ability of the process to process substantially plastic materials, which also contain large amounts of components that are normally considered undesirable, such as paper and cardboard (cellulose) and polymers containing chlorinated or brominated compounds, such as polyvinyl chloride (PVC) and halogenated flame retardants.

[0021] A further advantage of the process disclosed in the present invention is the ability of the process to process substantially plastic materials having inconstant composition without problems of fouling or blocking.

[0022] A further advantage of the process disclosed in the present invention is the ability of the process to process substantially plastic materials. Such plastic materials are generally the remainders that could not be separated and reused in a selection process applied to plastic waste.

[0023] A further advantage of the process disclosed in the present invention is the ability of the process to produce high quality pyrolysis oils even when the substantially plastic material being processed has an inconstant composition, with respect to the resulting composition, thereby maintaining the substantially high quality liquid hydrocarbons produced at 25°C.

[0024] The present invention also relates to a mixture comprising hydrocarbons and tetrahydrofuran, the amount of such hydrocarbons being more than 90% by weight relative to the total weight of the mixture, and the amount of tetrahydrofuran being between 0.01% and 0.25% by weight relative to the total weight of the mixture. The present invention also relates to the use of the mixture, the mixture being fed to a cracking plant.

[0025] The present invention also relates to a reactor for pyrolyzing a substantially plastic material, by means of which at least liquid hydrocarbons are obtained, which are in a liquid state at 25° C. The present invention also relates to an apparatus for pyrolyzing a substantially plastic material, by means of which at least liquid hydrocarbons are obtained, which are in a liquid state at 25° C. The apparatus comprises at least one reactor and at least one pressure regulating system. The reactor is for pyrolyzing a substantially plastic material. The pressure regulation system is for said reactor and depends on the characteristics assessed in the substantially plastic material fed thereto and / or the characteristics assessed in the pyrolysis oil produced by said reactor. In the reactor, such a pressure regulation system is characterized by low latency.

[0026] (definition) In describing the present invention, unless specifically stated otherwise, ranges of values ​​(eg, ranges of pressure, temperature, amount, etc.) may be considered to be inclusive of both end values.

[0027] In the description of the present invention, unless specifically stated otherwise, proportions (or percentages or %) may be considered to be proportions (or percentages or %) by weight (i.e., by mass). The symbol "%" means percent, usually by weight (mass).

[0028] In the description of the present invention, the term "comprise" also includes the meaning "consist of", in certain limited cases.

[0029] In describing the present invention, the term "essentially consist of" means that a composition or preparation (a) necessarily contains the recited ingredients, and (b) is open to ingredients (or ingredients) not recited, which do not materially affect the basic and innovative characteristics (or properties) of the composition.

[0030] In the present description, delay (or latency) means the delay time from the start of the measurement of a characteristic parameter evaluated on the substantially plastic material fed and / or the pyrolysis oil produced by the reactor, where the measurement is started as soon as the pressure setpoint is set. In other words, it is the difference between the time when the pressure setpoint is set and the time when the measurement is started.

[0031] In the present description, unless specifically stated otherwise, maintaining a particular parameter (e.g., pressure) within a given range means that operations are actively performed to keep this parameter within the given range, for example by checking that a measurement value is within the given range and / or by adjusting the parameter via a feedback regulating system in which the value of this parameter is set within the given range. Preferably, maintaining a particular parameter (e.g., pressure) at a set value or within a suggested range refers to setting this parameter in a feedback control system to a value within the suggested range, such that the parameter reaches the set value or within the suggested range.

[0032] In the description of the present invention, unless specifically stated otherwise, liquid hydrocarbons that are in a liquid state at 25°C means mixtures of hydrocarbons that are in a liquid state at atmospheric pressure and 25°C.

[0033] In the context of the present invention, pyrolysis oil (or oils) means the products of pyrolysis (or pyrolysis) which are in the liquid state at atmospheric pressure and 25°C (generally obtained by condensation of pyrolysis vapours). Thus, the pyrolysis process according to the present invention produces (or produces) a pyrolysis oil (or oils) containing hydrocarbon(s).

[0034] In the context of this invention, pyrolysis vapour (or pyrolysis vapour) means the product generated during the pyrolysis process which is present in gaseous form in the pyrolysis reactor or which will be present in gaseous form under the conditions of temperature, pressure and composition of the pyrolysis.

[0035] In the context of this invention, pyrolysis residue (or pyrolysis residue) means the product, which is in liquid or solid state or in both liquid and solid state in the pyrolysis reactor, or which exists in liquid and / or solid state under the conditions of temperature, pressure and composition of the pyrolysis.

[0036] In the present description, unless specifically stated otherwise, the substantial absence (or absence) of oxygen means that the oxygen (understood as molecular oxygen) in the pyrolysis vapours (or vapors) is less than 2% by weight, preferably less than 0.8% by weight and even more preferably between 20 and 4000 ppm by weight, relative to the total weight of the composition of said vapours (or vapors).

[0037] In the context of this invention, a reactor and / or apparatus specifically designed for the pyrolysis of substantially plastic materials means that the reactor / apparatus produces or forms at least liquid hydrocarbon(s) that are liquid at 25° C. for the purpose of treating the substantially plastic materials.

[0038] In the present description, unless specifically stated otherwise, a nozzle means an opening made in the body of a device (e.g., a pyrolysis reactor) that allows for the entry or exit of a material or To fit sensors to measure physical properties (e.g. temperature, pressure, level, height), or Allows for the insertion of further components (or elements) (e.g., agitators, heating coils, baffles). No mention is made here of any particular fastening method (for example by flange or by threading) or their shape, although a circular shape is preferred.

[0039] In the present description, unless otherwise specifically stated, if the value of a parameter is equal to a maximum determined value X, it means that this parameter is equal to or less than X, and if the value of a parameter is equal to at least a certain value X, it means that this parameter is equal to or greater than X.

[0040] In the description of the present invention, unless otherwise specifically stated, the yield in the manufacture (or production) of a product (or product) means the ratio (or percentage or %) (or weight %) based on the weight of the product (or product) relative to all of the products (or products) produced.

[0041] Unless specifically stated otherwise, in this document "part" means part by weight and "parts" means parts by weight. Weight (or weight) means mass (i.e. kg in SI units). Unless specifically stated otherwise, the unit of measurement for pressure is bar. Where not expressly specified (or defined) and where pressure can refer to both an absolute or relative (gauge) value, the absolute value is intended. [Brief description of the drawings]

[0042] [Figure 1] Figure 1 shows a reactor for pyrolysis of a substantially plastic material, according to the invention, for obtaining at least liquid hydrocarbons, such hydrocarbons being in a liquid state at 25°C. [Diagram 2] FIG. 2 shows one embodiment of a demister (inertial type) (cyclone) according to the present invention. [Diagram 3] FIG. 3 shows a bottom (or lower) or top (or upper) embodiment of the reactor. [Figure 4] Figure 4 shows diagrammatically an apparatus for pyrolysis of a substantially plastic material, according to the invention, for obtaining at least liquid hydrocarbons, such hydrocarbons being in a liquid state at 25°C. [Diagram 5] FIG. 5 shows some embodiments of pressure control according to the present invention. [Figure 6] FIG. 6 illustrates an embodiment of a split range control mode according to the present invention. [Figure 7] FIG. 7 shows a graph comparing two different temperature profiles (T1 and T2) applied to the pyrolysis reaction. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0043] Detailed Description of the Invention A first aspect of the present invention is a process (or treatment or step or method) for pyrolyzing a substantially plastic material to obtain at least liquid hydrocarbons, such hydrocarbons being liquid at 25°C, comprising the steps (a) to (e) of: (a) feeding a substantially plastic material, optionally already in a molten (or dissolved) state and / or in a preheated (or preheated) state, into a reactor for pyrolysis, (b) subjecting the material to a temperature of between 330°C and 580°C and a pressure of between atmospheric and 13 bar(a) (absolute) in the substantial absence (or absence) of oxygen in a pyrolysis reactor; (c) maintaining (or holding or holding) the material in the pyrolysis reactor at a temperature between 330° C. and 580° C. for a time sufficient to produce (or form or produce) at least one effluent in a gaseous state in the pyrolysis reactor; (d) a step of adjusting the pressure in the pyrolysis reactor with respect to the characteristic parameters defined by the composition of the substantially plastic material and / or the characteristic parameters defined by the product of the pyrolysis process, while maintaining the pressure at a value between atmospheric pressure and 13 bar(a) (absolute), (e) 1. A process (or step) of partially or totally concentrating an effluent in a gaseous state, which process (or step) results in the formation (or production or manufacture) of at least one fluid comprising liquid hydrocarbons, such hydrocarbons being in a liquid state at 25° C., the fluid being quantitatively at least 10% by weight based on the weight of the substantially plastic material supplied (or fed). The process is preferably characterised by low delay (or latency) in the pressure adjustment process (or step) (d).

[0044] Low latency means a delay (or latency) of 600 seconds or less, preferably 100 seconds or less. According to one embodiment, the delay (or latency) is less than 50 seconds, and even more preferably between 0.1 and 15 seconds.

[0045] In step (d), any characteristic parameter defined by the composition of the substantially plastic material and / or the product of the pyrolysis process may be used to adjust the pressure, provided that the measurement of such characteristic parameter(s) complies with specific delay (or latency) time requirements.

[0046] This means, in particular, that any measurements that take longer times (or durations or times) compared to the specific delay (or latency) time (or period or time) requirements are not part of (or included in) the present invention.

[0047] The following measurement methods can be used with both substantially plastic materials and products of the pyrolysis process and are characterized by delay (or latency) times (or durations or times), such delay times being within the scope of the specific delay time requirements. UV-Vis absorption spectroscopy Fluorescence emission spectroscopy X-ray fluorescence emission spectroscopy (XRF) X-ray dispersion spectroscopy (EDX) Fourier transform mid-infrared absorption spectroscopy (FTIR) Fourier transform near infrared absorption spectroscopy (FT-NIR) Raman absorption spectroscopy Rotovibrational microwave spectroscopy Dynamic light scattering (DLS) Circular dichroism Photoacoustic spectroscopy Ultrafast laser spectroscopy Laser-induced Breakdown Spectroscopy (LIBS).

[0048] The time delay between the measurement of such a characteristic and the definition of the pressure set point may be very small (typically less than 1 second, and even more preferably less than 0.1 second), whereby the calculation of the set point is performed automatically by digital computation means (e.g. a computer, a distributed control system (DCS), a microcontroller, a programmable logic controller (PLC) or a field-programmable gate array (FPGA) and any combination thereof).

[0049] Thus, according to one embodiment, in relation to the characteristic parameters defined by the composition of the substantially plastic material and / or the characteristic parameters defined by the product of the pyrolysis process, adjusting the pressure in the pyrolysis reactor is characterized by measuring the characteristic parameter(s) using at least one of the above mentioned measurement methods, while maintaining the pressure at a value between atmospheric pressure and 13 bar(a) (absolute). According to a further embodiment, preferably the adjustment of the pressure is performed by calculating (or computing or calculating) a pressure set point (or set value or set point) using one of the digital computation means (or digital computation means) mentioned above.

[0050] In particular, it has been found that where the substantially plastic material being fed is not constant, and particularly where the substantially plastic material is characterized by high variability (as described in more detail below), the effect of low latency is surprisingly robust, stable and reliable pressure control.

[0051] The pressure regulation maintained in step (d) is preferably performed at least during pyrolysis of the substantially plastic material contained in the reactor, and thereby preferably at least during step (c), i.e., while maintaining the substantially plastic material in the pyrolysis reactor at a temperature between 330° C. and 580° C. for a period of time sufficient to produce at least one of the effluents in a gaseous state.

[0052] The hydrocarbon-containing fluid (or effluent) concentrated in step (e) is a pyrolysis oil (or pyrolysis oil), which is in a liquid state at 25°C.

[0053] Preferably, the substantially plastic material comprises a composition (or composition or composition) of various plastics (or plastic substances or plastics). Even more preferably, the composition of various plastics includes at least a polymer having a high H / C index (H / C index or H / C idx) (e.g., polyethylene, polypropylene, polyamide, polymethyl methacrylate, etc.) and a polymer having a low H / C index (H / C index or H / C idx) (e.g., polystyrene, polycarbonate, polyethylene terephthalate, etc.).

[0054] Alternatively or additionally, various plastic compositions may include high carbon index polymers (e.g., polyethylene (including LDPE, LLDPE, HDPE), polypropylene, polystyrene, elastomers) and low carbon index polymers (e.g., polyamide, polymethyl methacrylate, polyethylene terephthalate, polyvinyl chloride, and cellulose).

[0055] Preferably, the substantially plastic material is characterized by an H / C index (or H / C index or H / C idx) and has an H / C index of at least 70, preferably from 80 to 98, even more preferably from 85 to 96.

[0056] Preferably, the substantially plastic material is characterized by a carbon index (or carbon index or carbon index) and has a carbon index of at least 55, preferably from 65 to 95, even more preferably from 75 to 90.

[0057] The H / C index (or H / C index or H / C idx) is proportional to the ratio of the total mass of hydrogen atoms present in the substantially plastic material to the total mass of carbon atoms present in the substantially plastic material and is calculated using the following formula:

number

[0058] The carbon index is proportional to the ratio of the total mass of carbon atoms present in the substantially plastic material to the total mass of all atoms present in the substantially plastic material and is calculated using the following formula:

number

[0059] In certain embodiments, the substantially plastic material comprises at least one material that is not plastic (or plastic substance or plastic material) (or non-plastic material) in an amount ranging from 0.01% to 10% by weight, alternatively from 0.05% to 7.5% by weight, alternatively from 0.2% to 5% by weight, alternatively from 1.1% to 4% by weight, based on the weight of the substantially plastic material. The material (or substance or material) that is not plastic (or plastic substance or plastic) (or non-plastic material) preferably comprises at least one of the following materials (or substances or materials): Paper (or paper or paper products), cardboard (or cardboard or thick paper or corrugated board), Wood (or tree or timber), Compost (as defined by IUPAC in “Terminology for biorelated polymers and applications (IUPAC Recommendations 2012)”, Pure Appl. Chem., Vol. 84, No. 2, pp. 377-410, 2012, DOI 10.1351 / PAC-REC-10-12-04), Metallic materials (e.g. aluminium and steel) and / or Inert materials (or substances or materials) (or inert materials)

[0060] In certain embodiments, the substantially plastic material comprises an inorganic filler (e.g., silica, titanium oxide, talc, coke, graphite, carbon black, calcium carbonate, tricalcium phosphate, zeolite, aluminum silicate, geopolymer, titanate, perovskite). In certain embodiments, the inorganic filler (or mineral filler or inorganic filler) may be present in an amount of 0.01% to 10% by weight, preferably 0.1% to 5% by weight, based on the total weight of the substantially plastic material. In certain embodiments, the substantially plastic material comprises a final inorganic residue (ash) having an amount of at least 0.01% by weight, preferably 0.1% to 20% by weight, more preferably 0.4% to 12% by weight, and even more preferably 1.1% to 7% by weight, based on the weight of the substantially plastic material, as measured according to the methods described herein. In certain embodiments, the substantially plastic material includes brominated and chlorinated additives, particularly organobrominated and organochlorinated additives, which are used to render a plastic material fire-resistant or in any case to provide a flame-retardant property. Examples of such additives (or additives) are hexabromocyclododecane, decabromo-diphenyl oxide, polybrominated diphenyl ethers and brominated polymers (e.g. brominated styrene-butadiene copolymers or brominated polystyrene). In certain embodiments, the halogen content present in the substantially plastic material is in an amount of 0.01% to 10% by weight, preferably 0.1% to 3% by weight, based on the total weight of the substantially plastic material.

[0061] In certain embodiments, the substantially plastic material includes non-halogenated additives (or additives) that are used to impart fire resistant or, in any case, flame retardant properties to the plastic material (e.g., phosphorus and nitrogen compounds).

[0062] When the substantially plastic material comprises one or more of the above materials or substances, the process of pyrolysis according to the present invention is not adversely affected.

[0063] By "inconstant composition" of the substantially plastic material is meant that the composition (or composition or composition) fed to the pyrolysis reactor referred to in step (a) is variable (or changeable or indefinite or variable). In certain embodiments, the composition is variable, where the amount of at least one ingredient of the substantially plastic material varies by at least 1%, preferably at least 2%, more preferably at least 5%, and even more preferably at least 10% by weight based on the weight of the substantially plastic material. In certain embodiments, the composition is variable, where the atomic composition varies by at least 1% by weight, preferably at least 2% by weight, more preferably at least 5% by weight, and even more preferably at least 10% by weight, based on the weight of the substantially plastic material. Here, atomic composition is understood as the weight of the elements in the periodic table (i.e., the mass of all atoms of an element (e.g., carbon or hydrogen) contained in the substantially plastic material). In certain embodiments, the composition is variable (or changeable or indefinite or variable) where the hydrogen / carbon index (or index) (H / C index or H / C idx ) and / or the carbon index (or carbon index or carbon index) fluctuates (or changes) by at least 1%, preferably at least 2%, more preferably at least 5%, and even more preferably at least 10%.

[0064] In one embodiment, the variability is between different manufacturing batches. Alternatively or in combination, the composition is not constant because variability in the composition exists, even within the same batch, for example due to layering of materials. In fact, there may be stratification during transport. This generally results in an increase in concentration at the bottom of the heavier and / or small size or powdery plastics and at the top of the lighter and / or large size plastics.

[0065] Alternatively, the substantially plastic materials described above do not have a constant composition, since the materials are provided by various manufacturers or suppliers. Each manufacturer may use different manufacturing specifications and / or different manufacturing processes (or steps or treatments or methods) and therefore the products (or products or products) available may vary.

[0066] In one embodiment, the variability of the substantially plastic material fed to the pyrolysis reactor referred to in step (a) is within a certain period of time (1 week, preferably 3 days, even more preferably 1 day, even more preferably 12 hours, even more preferably 3 hours, even more preferably 1 hour, even more preferably 30 minutes, even more preferably 15 minutes).

[0067] Also preferably, the substantially plastic material is recycled (or reused).

[0068] In certain embodiments, the substantially plastic material includes a halogenated component in an amount ranging from 0.01% to 10% by weight, based on the weight of the substantially plastic material.

[0069] Preferably, said substantially plastic material is obtained by a process (or step or treatment or method) of selecting (or selecting or sorting or sorting) a plastic material. Even more preferably, said substantially plastic material is a residual substantially plastic material. Such a material is a substantially plastic fraction. Such a fraction is what remains after recovering a portion of the plastic from the substantially plastic material fed to a selection process or what remains after selectively extracting a portion of the plastic. Selective extraction comprises the extraction of a substantially homogeneous material of a particular plastic (i.e., as a single plastic or single plastic or monoplastic). Typically, in the selection process (sorting or sorting), a substantially pure plastic stream (i.e., as a single plastic or single plastic material or single plastic or monoplastic) of the components (polyethylene, polypropylene and polyethylene terephthalate) can be extracted (or extracted). Thus, in such a preferred selection, the remaining (or residue or remainder or residue) substantially plastic material is the material (or substance or material) obtained after extraction of said substantially pure (or pure) plastic (or plastic substance or plastic). Such fractions are known in Italy by the term "Plas Mix" or "Plasmixes". They are defined as "a collection or set of heterogeneous plastic substances or heterogeneous plastics contained in post-consumer packaging and which have not been recovered as a single polymer" (Article 1 of the draft Atto Camera law 4502 of 18 May 2017).

[0070] Such substantially plastic materials can be further selected, such that materials that cannot be recycled (or reused) can be eliminated or can be used as is.

[0071] In particular, according to a preferred method, said substantially plastic material is obtained, possibly by a process (or step or treatment or method) of sorting plastic materials (as defined above) and, after a pre-treatment, is used in the process of pyrolysis according to the invention.

[0072] Such pre-treatment preferably includes a suitable washing, thereby removing at least a portion of the organic matter. Preferably, the above pretreatment also includes, alternatively or in combination, the elimination of non-organic solid particles (such as ferrous materials and crushed stone).

[0073] A second aspect of the present invention is a reactor for pyrolyzing a substantially plastic material, the reactor being for obtaining at least liquid hydrocarbons, such hydrocarbons being in a liquid state at 25° C. The method includes the steps of: (i) at least one port for exiting a gaseous product, such port being located at the top (or upper portion or apex) of the reactor or at a distance from the top (or upper portion or apex) of the reactor, such distance being no more than 1 / 3 of the height of the reactor; (ii) At least one port for removing solid product, located at the bottom of the reactor or at a distance from the bottom of the reactor, such distance being not more than 1 / 3 of the height of the reactor; (iii) at least one port for admitting a substantially plastic material, the port being at a distance from the top of the reactor that is greater than the distance from the top of the reactor of a port for withdrawing a gaseous product; (iv) At least one stirrer (or agitator); (v) at least one jacket for heating the reactor; (vi) at least one opening for inserting a temperature transducer; (vii) at least one opening for inserting a pressure transducer; (viii) At least one opening for inserting a sensor for measuring the level (or height) of the reactor. The method is characterized by the presence of a separator (demister) (for carry-over material) located below and / or at the port for exiting the gaseous product. Also, according to one embodiment, the reactor is characterized by a design pressure (or specified pressure or set pressure or design pressure or design temperature) and a design temperature (or specified pressure or set pressure or design temperature or design temperature). The design pressure is at least 3 bar (absolute (a)), preferably at least 4 bar (absolute (a)), even more preferably at least 6 bar (absolute (a)). The design temperature is at least 330°C, preferably at least 380°C, even more preferably at least 430°C, even more preferably at least 480°C. Also, according to one embodiment, the reactor is characterized by a substantially convex profile (i.e., the concave volume is greater than 10% of the total volume of the reactor).

[0074] According to one embodiment, in said stirrer (iv), at least one agitator element (or agitator element or stirrer element) for stirring (or agitating) the fluid in a non-gaseous state (or fluid) is arranged at a height, said height being equal to or lower than the height of the port (or entry port) for the entry of the substantially plastic material.

[0075] Figure 1 shows an example of a reactor, which includes: - a body (11) in which a reaction of thermal decomposition of a substantially plastic material proceeds, - a stirrer (12) for moving and mixing the substantially plastic material and the products of pyrolysis, - a jacket (13) through which a heat transfer fluid flows to provide the necessary heat to heat the substantially plastic material for pyrolysis; - a port (N1) for receiving a substantially plastic material (or an entry port), - a port (N2) for the exit of the gaseous product (i.e. pyrolysis vapours), - a port (N3) for removing the products and / or associated mixtures in solid or liquid form (i.e. residues of the pyrolysis), - an opening (NP) for inserting a sensor for measuring the pressure, - an opening (NL) for inserting a sensor for measuring the level (or height), An opening (NT) for inserting a sensor for measuring the temperature.

[0076] The following is also shown in the figure: - a height (D1) corresponding to the distance from the top of the reactor to the center of the port (N1); - a height (D2) corresponding to the distance from the top of the reactor to the center of the port (N2), - height (DJ) corresponding to the distance from the top (or upper part or apex) of the reactor to the highest point (or point) of the body (11) of the reactor heated by the jacket (13); - height (DS) corresponding to the distance from the top of the reactor to the highest point of the mixing element of the stirrer, a height (not shown in the drawing figures, since it is equal to zero), corresponding to the distance from the bottom of the reactor to the center of the port (N3); - the height (H) of the reactor, which corresponds to the distance from the top (or upper part or apex) of the reactor to the bottom (or lower part or bottom) of the reactor (i.e. the maximum axial distance (but vertical)); - a height (H / 3) which corresponds to one third (1 / 3) of the height (H) of the reactor.

[0077] In all the above distances, vertical distances are intended, i.e. distances measured axially (but vertically), and therefore not point-to-point distances (which are equal to or greater than the horizontal distances, which also contribute to the latter, according to the Pythagorean theorem).

[0078] All the above distances are measured inside the body (11) of the reactor, i.e. for example, the height (H) of the reactor is measured inside it (as shown in FIG. 1).

[0079] As described, the reactor has a substantially convex (or convex-like or convex or convex) profile (or shape). A convex (or convex-like or convex surface or convex) profile (or shape) means that, taking any two given points inside the reactor, the line (or segment) joining them lies completely (or entirely) inside the reactor. A line (or segment) inside the reactor means that each point of the line is within the reactor or is located on the interior surface of the reactor. A substantially convex (or convex or convex or convex) profile (or shape) means that its concave volume (or concave or concave or concave volume or volume or volume) (or concave volume) is at most 10% of the total volume (or total volume or total volume) of the reactor (or total reactor volume), preferably at most 5% of the total volume of the reactor. A concave volume means a volume in which there is at least one point such that another point (not necessarily within said volume) can be identified within the reactor, and such that the line connecting them is not completely (or wholly) within the reactor. As a special case, a substantially convex (or convex-like or convex or convex) profile (or shape) is a convex (or convex-like or convex or convex) profile (or shape).

[0080] Preferably, the reactor body is substantially axisymmetric, i.e. it has an axis of symmetry and its shape can be obtained substantially by a 360 degree rotation (or rotational movement or revolution) of the profile (or shape). An example of an axisymmetric shape is as follows: A flat edge (or flat end or flat end) (obtained by rotation (or rotary motion or revolution) of a rectangular profile (or shape) with an axis of symmetry perpendicular to the longest side of the rectangle), tubular profile (obtained by rotation of a rectangular profile with an axis of symmetry parallel to the longest side of the rectangle), Tapered ends (obtained by rotation (or rotary movement or revolution) of a non-aligned rectangular profile (or shape) about an axis of symmetry), and A spherical (sometimes called hemispherical), elliptical or semi-elliptical end (obtained by rotation (or a rotary motion or revolution) of a curved profile (or shape).

[0081] Preferably, the reactor body is formed by a shell. The shell is made up of three parts, the ends of which are firmly connected, and the body comprises a central body, an upper end and a lower end. The reactor body preferably has a cylindrical and / or tapered profile and / or is a composition of a cylindrical profile and a tapered profile, the internal surface of which forms the inner lateral surface of the reactor.

[0082] The ends are preferably rigidly connected at their extremities to a central part, thereby forming a substantially closed body, to which pressure can be applied.

[0083] Even more preferably, the edge (or edge or end) follows one of the geometries (or shapes) shown in FIG.

[0084] More preferably, the lower end (or lower end or lower end) is of the pseudo-elliptical, elliptical or hemispherical type. Even more preferably, the lower end is of the hemispherical type.

[0085] More preferably, the upper end (or upper edge or upper end) is of the flat, pseudo-elliptical, elliptical or hemispherical type. Even more preferably, the upper end is of the hemispherical type.

[0086] The rigid connection between the ends and the central body may be formed by any method known in the art, for example by welding, brazing, riveting or by means of a flange connection.

[0087] By substantially axisymmetric reactor body is meant that at most 15% of the reactor capacity (or volume or volume) cannot be obtained by a 360 degree rotation (or rotational movement or revolution) of any profile (or shape) and therefore must be added to or subtracted from the capacity (or volume or volume or volume) formed by a 360 degree rotation (or rotational movement or revolution) of the profile (or shape).

[0088] The reactor is preferably of upright type (or upright type or vertical type), i.e. the axis of symmetry of the shell is parallel to the vector of the load (or weight force) (gravity).

[0089] Applicant notes that the geometry of the reactor as disclosed herein, and in particular the substantially convex profile, generally makes it possible not only to reduce the thickness (thickness required to withstand the relatively high process pressures required for the process) but also to limit fouling. The reduced thickness also allows for increased and more uniform heat exchange with the fluid in the jacket, since the thermal resistance through the thickness of the reactor body is reduced.

[0090] A third aspect of the invention is an apparatus for pyrolyzing a substantially plastic material (or plastics material or plastic substance material or plastic material) to obtain at least liquid hydrocarbons, such hydrocarbons being in a liquid state at 25° C. The apparatus comprises: - at least one reactor for the pyrolysis of a substantially plastic material, - at least one condensation separator (or condensation separator or condensation separator) for condensing and separating the steam (or vapour) produced (or formed or generated or produced) by the reactor; - at least one system for regulating the pressure of the reactor in relation to a characteristic assessed in the substantially plastic material fed thereto and / or a characteristic assessed in the pyrolysis oil produced by the reactor and / or in the liquid hydrocarbons (which are liquid at 25°C) produced.

[0091] According to one embodiment, in the device for pyrolyzing a substantially plastic material, the system for regulating the pressure in the reactor is operated according to one or more of the following modes: - regulating the heat extracted from a condensation separator located downstream of the reactor and in fluid connection with the reactor, preferably by regulating the power of the condensation separator. If an auxiliary gaseous fluid is provided, adjusting the flow rate of this auxiliary gaseous fluid. - controlling the pressure regulation of the pyrolysis vapours by adjusting the opening of valves through which the pyrolysis vapours pass and then enter at least one condensation separator. - controlling the pressure regulation of the residual gas by adjusting the opening of a valve through which the residual gas passes, the gas being made up of a fluid containing hydrocarbons, the hydrocarbons not having been condensed after passing through at least one enrichment separator. - Double pressure regulation (or pressure regulation) by a combination of a control mode for regulating the pressure of the pyrolysis vapours and a control mode for regulating the pressure of the residual gas (or residue).

[0092] A schematic diagram of one embodiment of the above device is shown in Figure 4. The diagram shows the following components: - a reactor (70) for pyrolysis of the substantially plastic material (54), producing pyrolysis vapours (52) and solid residues (53), which may optionally receive an auxiliary gaseous (or gaseous) fluid (51); - a second reactor (71) for subjecting the pyrolysis vapors (52) coming from the pyrolysis reactor (70) (or the incoming pyrolysis vapors (52)) to a thermal or thermo-catalytic treatment; - a first pressure control device (72), for example a valve, acting by feedback on the value of the pressure (80) measured in the pyrolysis reactor (70) for receiving the pyrolysis vapors (63) from the second reactor (71) (although in an alternative embodiment this could alternatively be located between the reactor (70) and the reactor (71) (i.e. for receiving the pyrolysis vapors (52)); - a first concentrator (or condenser) (73) for receiving the pyrolysis vapors (64) and the concentrate (or condensate) (60) which are partially returned (55) to the pyrolysis reactor (70); - a second concentrator (or condenser) (74) for receiving (or accepting) the vapor (57) coming from the first concentrator (73) (wherein the second concentrator (74) produces (or forms) a second concentrate (or condensate) (61) and vapor (58); - a third condenser (75) for receiving the vapor (58) from the second condenser (74), the third condenser (75) producing (or forming) a third concentrate (62) and a non-condensed vapor or residual gas (59); a second device (or equipment) (76) for regulating (or managing or controlling) the pressure, for example a valve, acting by feedback in relation to the value of the pressure (80) measured in the pyrolysis reactor (70) to regulate (or limit) the cross section (area) of the passage (or passage) of the residual gas (59) discharged from the condenser and then to send the residual gas (56) to a unit (unit capable of receiving the gas (56)).

[0093] In the above pressure regulation system, when the characteristics of the substantially plastic material fed to the reactor are evaluated, they should preferably be regulated in relation to the H / C index (H / C index or H / C idx) and / or the carbon index (Carbon Index or CI) of the substantially plastic material, or based on a mathematical relationship taking into account both the H / C index and the carbon index of the substantially plastic material.

[0094] In the above pressure regulating system, when evaluating the above features (or characteristics) of the pyrolysis oil (or oils) (or pyrolysis oils) produced (or formed) by the above reactor and / or the hydrocarbons produced (or formed) that are liquid at 25°C, it is preferred that such features (or characteristics) are the refractive index, viscosity or molecular weight of the pyrolysis oil (or oils) (or pyrolysis oils).

[0095] (Preferred mode (or form or aspect) of the process according to the present invention) According to a preferred method, the substantially plastic material provided (or fed) to the reactor in step (a) is pre-melted (or dissolved) and / or pre-heated in a pre-heating device. This preheating device may be a single screw extruder, a twin screw extruder or an auger. Such a preheater may involve degassing to evacuate water vapor and any other produced gases (e.g., hydrogen chloride (HCl) in particular).

[0096] For this purpose, it may be advantageous to also supply the preheating device with an additive (or additives) in addition to the substantially plastic material, which is capable of promoting the generation of hydrochloric acid (or hydrochloric acid) and converting it back into salt. Such additives (or dopants) are preferably composed of elements of Groups IA and IIA. Even more preferably, such additives (or additives) are oxides (or oxides), hydroxides (or hydroxides), carbonates (or carbonates), silicates (or silicates) and aluminosilicates (those from groups IA and IIA). Even more preferably, such additives (or additives) are calcium oxide (or calcium oxide), calcium hydroxide (or calcium hydroxide), calcium carbonate (or calcium carbonate), sodium oxide (or sodium oxide), sodium hydroxide (or sodium hydroxide), sodium carbonate (or sodium carbonate), potassium oxide (or potassium oxide), potassium hydroxide (or potassium hydroxide), potassium carbonate (or potassium carbonate), sodium aluminosilicate (or sodium aluminosilicate).

[0097] The preheating temperature may be from 120°C to 430°C, preferably from 150°C to 320°C, and even more preferably from 180°C to 220°C. The residence time in the preheating device is preferably less than 10 minutes, even more preferably less than 2 minutes, in particular from 15 seconds to 1 minute.

[0098] The process for pyrolyzing a substantially plastic material to obtain at least liquid hydrocarbons (those that are liquid at 25° C.) may be carried out in batch mode, continuous mode, or semi-continuous mode. In the latter mode, the substantially plastic material is continuously loaded and the generated vapors are continuously extracted, provided that any solid remainder is maintained inside the pyrolysis reactor.

[0099] If the amount of solid residue inside the reactor increases beyond a certain threshold or increases at a predefined interval of time (for example, a frequency ranging from 2 days to 10 days), the material contained in the reactor, and thus the solid residue, is removed.

[0100] Preferably, the reactor is operated in a continuous or semi-continuous mode, and even more preferably in a semi-continuous mode.

[0101] Although the reactors described above are preferred, the pyrolysis process according to the present invention is not limited (or restricted) to any particular type (or kind) of reactor.

[0102] In particular, horizontal (or inverted) or vertical (or upright), stirred or unstirred reactors, kiln reactors or screw reactors may be used, whereas fluidized bed reactors are not preferred.

[0103] Among stirred reactors, continuously stirred reactors (CSTRs) and multizone reactors may be used. A piston flow reactor (PFR), preferably a stirred type, can also be used to facilitate heat transfer (or thermal transport).

[0104] Continuously stirred reactors (CSTRs) may be used, including fully packed reactors and reactors that separate the gas phase from the liquid phase and other possible phases, such as solid (char) products (i.e., reactors with a free surface).

[0105] Preferably, the reactor is a stirred reactor. Preferably, the reactor has a free surface (i.e., a surface that substantially separates a gas phase from a substantially non-gaseous phase). Substantially non-gaseous phases include, for example, phases that include solids and liquids, and by liquid we mean molten (or dissolved) material (such as the substantially plastic material being fed). Such a substantially non-gaseous phase may in any case include a gas phase (e.g., bubbles of steam (or vapor) rising toward the pyrolysis product reactor).

[0106] Step (b) of the process according to the invention is carried out in the substantial absence of oxygen. Such substantially plastic materials typically do not generate significant amounts of molecular oxygen during pyrolysis, and therefore this condition is usually reached automatically after a few hours after the process begins. However, after stopping the cycle and / or opening the reactor, it is preferable to inject an auxiliary gaseous (or gaseous) fluid in order to avoid autoignition phenomena. An example of a possible auxiliary gaseous fluid is a gas (or gases) that is inert (or inert gas) at the reaction conditions of the pyrolysis (by inert gas we mean a gas that does not substantially react at the process conditions of the pyrolysis reactor). Examples of such inert gases (or gases) (or inert gases) are nitrogen, argon, water vapor, carbon dioxide and relative mixtures. Such a gas can be fed prior to feeding the substantially plastic material to the pyrolysis reactor in order to remove any oxygen present in the atmosphere. Other possible choices for the auxiliary gas fluid are described below.

[0107] The temperature to which the material is subjected in the pyrolysis reactor is 330°C to 580°C, preferably 340 to 540°C, even more preferably 360 to 500°C, even more preferably 380 to 480°C, even more preferably 410 to 450°C.

[0108] The temperature of the material in the pyrolysis reactor can be measured by any method known in the art. For example, a thermocouple with a facing membrane disposed (or aligned) on the inner surface of the reactor to reduce fouling; or Enough thermocouples to measure more accurately inside the reactor; or A thermocouple measuring the temperature of the metal near the polymer-wetted reactor surface; or Non-contact measuring systems, e.g. infrared measuring systems can be used. For better reliability, multiple systems may be used simultaneously.

[0109] The temperature may be adjusted by acting on (or influencing) the heat power (or heat power or thermal power) introduced into the reactor. The heat power may be introduced by using any technique known in the art, such as a reactor equipped with a heating jacket through which a suitable heat transfer fluid flows, or a direct electric heating system by Joule effect, or even electric induction heating. Heating may also be affected using microwaves (or microwaves). Heating by means of a heating jacket (or heating jacket) is particularly preferred.

[0110] If a heat transfer fluid is used, this may be a molten salt. Preferably, the heat transfer fluid has a low melting point. More preferably, the melting point is at most 310°C, even more preferably at most 250°C, even more preferably at most 220°C. Preferably, such heat transfer fluids have a high decomposition temperature. More preferably, the decomposition temperature is at least 400°C, more preferably at least 450°C, even more preferably at least 490°C, even more preferably at least 540°C.

[0111] Preferably, such heat transfer fluids have a low chloride content. Preferably the chloride is less than 1000 ppm by weight. Even more preferably, the chloride is less than 100 ppm by weight.

[0112] According to one embodiment, the heat transfer fluid is a molten salt (or molten salt or molten salt), such as nitrates and carbonates of metals (from groups IA and IIA), preferably sodium nitrate, sodium nitrite, potassium nitrite, potassium nitrate, lithium nitrate, calcium nitrate and mixtures thereof. According to a further embodiment, the heat transfer fluid is a molten salt (or molten salt or molten salt), such as metal carbonates (from groups IA and IIA), preferably lithium, calcium, sodium, potassium carbonates and mixtures thereof. According to a further embodiment, the heat transfer fluid is a molten salt (or molten salt or molten salt), such as metal fluorides (from groups IA and IIA), preferably lithium, sodium, potassium and calcium fluorides. Even more preferably, the heat transfer fluid comprises a molten salt (or molten salts), such salts including sodium nitrite (or sodium nitrite), sodium nitrate (or sodium nitrate) and potassium nitrate (or potassium nitrate). Even more preferably, the heat transfer fluid comprises a molten salt (or molten salt or molten salt). Such salts include sodium nitrate (or sodium nitrate) and potassium nitrate (or potassium nitrate). When a preheating device is used, the heat transfer fluid may advantageously be fed first to the pyrolysis reactor and then to the preheating device, or may be fed in parallel.

[0113] According to one embodiment, the heat transfer fluid is an organic-based heat transfer fluid of semi-synthetic or synthetic origin (e.g., Dowtherm A, Marlotherm SH, Mobiltherm, Santotherm, Therminol 66, Therminol SP, etc.). According to a further embodiment, the heat transfer fluid is a silicone fluid (or silicone fluid) (eg, Syltherm 800, Duratherm S, or Gelest PDM 0821). Such silicone resin fluids can be operated at higher temperatures (even above 380° C.) and do not need to be pressurized. The use of silicone resin fluids also allows for a significant reduction in fluid replacement due to their greater thermal stability. According to a preferred method, the pyrolysis vapors produced by the pyrolysis reactor are subsequently passed through at least one condensation separator, so as to recover at least liquid hydrocarbons (those that are in a liquid state at 25° C.) (as defined in the present invention).

[0114] Condensation separator means any device that is capable of receiving a fluid in a gaseous state and removing sufficient heat from the fluid to cause at least a portion of the fluid to form in a liquid state.

[0115] An example of equipment is a concentrator (or condenser), e.g., a concentrator (or condenser) that includes a coil inside which a heat transfer fluid flows, capable of removing heat from a fluid (a gaseous (or gaseous) state that will be treated).

[0116] Other methods of removing heat may also be used. For example, alternatively or in combination, the condensation separator may be provided with a jacket in which a heat transfer fluid can remove the heat flow.

[0117] Advantageously, flooding concentrators can also be used, which are partly flooded by the liquid phase produced and whose concentrating power is adjusted by varying the depth of the liquid phase, since only the coils not flooded can absorb calories from the steam to be condensed. This therefore allows the power (or output) of the concentrator to be effectively adjusted.

[0118] Alternatively, the concentration separator may be a distillation column. In this case, a concentrated fluid is generated in the column concentrator (or column condenser), and the concentrated liquid flows back into the column by gravity or by pumping, concentrating the vapor inside the column. By using a distillation column type of concentration separator, a better fractionation of the incoming vapor is also obtained, i.e., a separation between the higher boiling components (i.e., the components to be concentrated) and the lower boiling components (i.e., the components remaining in the vapor phase) is obtained, because each equilibrium stage allows the heavy components to be concentrated in the liquid phase and the light components to be concentrated in the vapor phase. Additionally, the concentrated liquid falls back down the column, scrubbing the steam (or vapor) inside the distillation column. This results in the pick-up of solid particles present in the incoming vapor, which then completes the collection in the liquid phase.

[0119] A further advantage of using a distillation column is that the column can be operated at a higher temperature to obtain the same effluent in gaseous form, as compared to a single condenser (which is essentially the equivalent of an equilibrium stage separator). This is advantageous because the temperature in the pyrolysis reactor is usually higher than the condensation temperature in the condensation separator. Thus, when the liquid effluent of the distillation column is partially recycled to the pyrolysis reactor, the higher temperature recycled concentrate makes it possible to reduce the heat energy that must be supplied to the pyrolysis reactor.

[0120] Advantageously, the column does not have a boiler and the inlet for steam (or vapour) to the column is located (or arranged) in the lower half of the column, even more preferably at the bottom (or lower part or base).

[0121] The power (or output) of the concentrating separator may be adjusted in any manner (or method or manner) known in the art. According to a first preferred method, the power (or output) of the concentration separator may be regulated by acting on (or actuating or influencing) the temperature of the heat transfer fluid. In this way, the heat difference between the process fluid and the heat transfer fluid, and therefore the power (or output) exchanged, actually varies.

[0122] According to a second preferred method, such power may be adjusted by acting on (or actuating or influencing) the flow rate of the heat transfer fluid. According to a third preferred method, such power (or output) may be regulated by acting on (or actuating or influencing) the level (or height) of the heat transfer fluid in the jacket. If the thickening separator is a flooding thickener (or flooding condenser), according to a further preferred method the power (or output) of the thickening separator is adjusted by varying the depth (or height) of the liquid phase produced. The latter mode (or form or aspect) is illustrated in Figure 5, which shows a flood-type thickener separator (75). The thickener separator (75) is equipped with a level sensor (LT) and a system of level control by adjusting the aperture (or opening) of a valve (78) at the concentrate (or condensate) outlet (62).

[0123] Referring to Figure 5, a pyrolysis reactor (70) receives a substantially plastic material (54) at its inlet and, optionally, a supplemental gaseous fluid (51) to produce a solid residue (53) and pyrolysis vapors that are directed to at least one condensation separator (75). Optional control valve (72) receives pyrolysis vapors from pyrolysis reactor (70) and routes the pyrolysis vapors to condensation separator (75). The aperture (or opening) is controlled by signal (85).

[0124] The concentrator separator (75) in FIG. 5 is a flooding concentrator (or flooding condenser). The condensed fluid is flooded into the bottom of the condenser, and condensation is achieved by sending a heat transfer fluid (which is cooler than the pyrolysis vapors) through a jacket or coil positioned (or arranged) so that the portion of the jacket in contact with the vapor (to be condensed) changes depending on the level (or height) of the condensed liquid (e.g., by applying a jacket to the side wall of the condenser).

[0125] An optional regulating valve (76) regulates the pressure by restricting the cross-section of the passage of the residual gas (59), which is then sent to the receiving unit (56).

[0126] An optional control valve (78) regulates the outflow (or effluent) of concentrated fluid (62), i.e., the flooding level of the flooding concentrator (75).

[0127] An optional control valve (77) adjusts the flow rate of the auxiliary gaseous fluid entering the pyrolysis reactor (70).

[0128] The level controller (LIC) reads a level signal (or height signal) (83) at the flooding concentrator (75), which is measured by a level sensor (or height sensor) (LT). The level controller (LIC) then adjusts the aperture (or throttle or opening) of the valve (78) through feedback to ensure that the level (83) corresponds to the set point (or set point or set point indication) (86) received from the PIC controller. To be consistent with what is shown in FIG. 6 and to fit the cooling power concept, it should be noted that the set point indication (86) is equal to 0 at 100% level (i.e. maximum flooding = minimum concentrating power) and 100 at 0% level (i.e. empty concentrator = maximum concentrating power).

[0129] Also, to be consistent with that shown in FIG. 6, the opening indication (87) sent to valve (76) is equal to 0 when the valve is closed and equal to 100 when the valve is fully open.

[0130] The opening indication (84) sent to valve (77) is operated in reverse mode because valve (77) must open to increase reactor (80) pressure and must close to decrease reactor (80) pressure.

[0131] The pressure signal (80) from the pyrolysis reactor may result in several pressure transducer processing, as described below. Additionally, as shown in the figure and described below, detection can be performed in the clean fluid sent to the pyrolysis reactor (near the outlet, the fluid directed to the reactor) so that the transducer membrane remains clean. The figure shows the acquisition of a pressure signal from a conduit which transports an auxiliary gaseous fluid (51) to a pyrolysis reactor.

[0132] The pyrolysis reactor pressure set point (PS) may be set locally (i.e. manually, for example by setting a value at the plant control panel) or it may be set remotely (i.e. from an external setting signal).

[0133] Such an external signal may be, for example, a set point (81) calculated based on one or more parameters read at the substantially plastic material (54) arriving at the pyrolysis reactor. For example, this pressure set point may be an expression in which the variables are the H / C index and the carbon index of the substantially plastic material (measured in-line, on-line or off-line by an analyzer (at INPUT)).

[0134] Alternatively, such an external signal may be a setpoint (82) calculated by a feedback controller (AIC), which adjusts the setpoint (82) so that a parameter representative of the quality of the product (liquid state) obtained after concentration (62) (measured in-line, on-line or off-line by an analyzer (at OUTPUT)) reaches a target value.

[0135] The pressure controller (PIC) reads the pressure signal (80), compares the pressure signal (80) to a set point (PS), and activates one of the regulating devices (84, 85, 86, 87), either separately or in combination, using, for example, a PID (proportional, integral, derivative) algorithm, via feedback, to minimize the error between the read signal (80) and the set point (PS). An example of the above combination embodiment is obtained by using adjustment device (86) and adjustment device (87) in a split-range mode (as will be explained more fully below).

[0136] With reference to the graph of figure 6 and in view of the diagram of figure 5, the abscissa indicates the OP (operating point) determined by the controller (PIC), which may for example be output from the controller to a PID algorithm and is calculated based on the difference between the detected pressure signal (80) and a set point (SP). OP=0 gives maximum pressure, and OP=100 gives minimum pressure. The ordinate indicates YP, which is the signal (or signals) sent to the regulating devices (eg, the regulating devices shown at 84, 85, 86, 87 in FIG. 5).

[0137] According to one embodiment, the regulating devices, when operated individually, have a YP that is a linear signal with respect to the OP calculated by the PIC. For example, a pressure control valve for pyrolysis vapors released from the reactor (72) can receive an opening value YP (85). For the value of the aperture YP (85), when OP=0, YP is equal to 0 (the aim is to increase the pressure in the pyrolysis reactor), and when OP=100, YP is equal to 100 (the aim is to reduce the pressure in the pyrolysis reactor to a maximum). The corresponding curve (or curves) in FIG. 6 is the solid line 85. As a further example, the auxiliary gas fluid pressure regulating valve (77) typically receives an inverse signal. That is, when OP=100, YP is equal to 0, and when OP=0, YP is equal to 100 (the curve (or curves) are not shown in FIG. 6 in order to maintain the same clarity).

[0138] According to an alternative embodiment shown in Figure 6 ("split-range" control mode), and read in light of the diagram of Figure 5, a level controller (LIC) is used in combination with a valve (76) by a signal (86). The opening of the valve (76) is controlled by a signal (87). If the value of OP is between 0 and 50, the signal (87) sent to the valve (76) remains at 0 (the valve remains closed or at a preset minimum opening value, e.g. 10%), while the signal (86) of the level in the concentrator fluctuates. For example, signal (86) may be set to 0 when OP=0 (the concentrate level in the flooding concentrator is at its maximum value) and 100 when OP=50 (the concentrate level in the flooding concentrator is at its minimum value), varying linearly between these two values. In this way, the pressure is varied by changing the output (or power) of the concentrator. If the value of OP is between 50 and 100, the signal (86) is maintained at a maximum level. The signal (87) is gradually changed relative to the aperture (or opening) of the valve (76). In this way, the pressure in the pyrolysis reactor is adjusted (as will be explained in more detail below) by varying the output (or power) of the condenser, but if this is not sufficient, the condenser is maintained at maximum output (or power) and the pressure of the residual (or residue or remaining or residue) gas (59) is adjusted by changing the opening (or aperture or opening) of the pressure control valve (76). Under relatively steady-state conditions, the pyrolysis process generally produces gases that cannot be condensed. In such cases, the adjustment is made in this mode, where the value of OP remains between 50 and 100, operating the condenser at maximum output power, while adjusting the pressure control valve (76) instead. During a start, stop or strong variation of conditions (e.g. due to a change in the substantially plastic material being fed) the steam generation may decrease. This results in a decrease in the value of OP (which may be less than 50). Thus, the steam (vapor) becomes concentrated. In this way it is possible to maintain the target pressure even during transitional (or transient) periods. This allows the efficiency of the process (or step or treatment or method) to be maximized. That is, to ensure optimal pressure control and at the same time to limit the flow rate of the remaining gas. Therefore, split range mode is generally one of the best ways to regulate pressure during pyrolysis, as it allows for efficient management of such transients with only a small increase in the complexity of the regulation system.

[0139] These methods can be used individually or, where possible, in combination.

[0140] Remainder (or residue or remaining or residue) gas (or gas) means the fluid (or fluids) containing hydrocarbon(s) that has not been concentrated after passing through at least one concentration separator. This remaining gas (or residue) preferably comprises at least 40% by weight of light hydrocarbons (C1-C5) (or light or light hydrocarbons (C1-C5)), based on the total weight of this remaining gas, and can advantageously be used as a fuel gas (or fuel gas). A portion of such remaining gas may be recycled (or reused or circulated) in the pyrolysis reactor (after pressurization) as an auxiliary gaseous fluid (as described in greater detail below), or a portion of such remaining gas may be combusted to provide the heat energy required for the pyrolysis process. For this purpose, for example, a gas heater may be used, for example by means of which the temperature of a heat transfer fluid circulating in the jacket of the reactor may be regulated. Alternatively or in combination, such residual gases may advantageously be used to supply (or feed) a refinery plant (or refinery plant), such as a cracking plant or a cracking plant or a decomposition plant.

[0141] According to the invention, the fluid in liquid state after concentration in the at least one concentration separator is quantitatively at least 10% by weight, preferably between 20% and 92% by weight, even more preferably between 30% and 85% by weight, even more preferably between 40% and 75% by weight, relative to the mass of the substantially plastic material supplied. When more than one thickener separator is used, the above amounts are calculated by adding the amount of liquid (by mass) produced in each thickener separator.

[0142] According to a preferred method, the at least one condensation separator through which the pyrolysis vapours produced by the pyrolysis reactor pass consists of at least two condensation separators. In this mode (or configuration or embodiment), at least two concentrating separators are arranged in series (or in series or in series). Each of the enrichment separators receives (or receives) the non-enriched gas (or gas) discharged from the previous enrichment separator, while the first enrichment separator receives (or receives) the vapors of the pyrolysis.

[0143] In this preferred mode (or form or embodiment), the concentrate separator receiving the pyrolysis vapors (the first concentrate separator) operates at a higher temperature than the second concentrate separator (the concentrate separator receiving the unconcentrated vapors originating from the first concentrate separator). According to a further embodiment, when several enrichment separators are present in series (or in series or in series), each enrichment separator receiving vapor from a (previous enrichment separator) is operated (or operated) at a lower temperature than the previous enrichment separator.

[0144] According to one embodiment, there are three enrichment separators. Preferably, at least the first enrichment separator consists of a distillation column.

[0145] If there are at least three thickening separators, preferably the temperature of the liquid effluent of the third (or last) thickening separator is in the range of 220-420°C, preferably 240-370°C, even more preferably 250-340°C.

[0146] When there are at least two thickening separators, the temperature of the liquid effluent of the second (or second) thickening separator is in the range of 100-320°C, preferably 120-260°C, even more preferably 140-220°C.

[0147] When at least one thickening separator is present, the temperature of the liquid effluent of the last thickening separator is in the range of -10 to 150°C, preferably 25 to 100°C, even more preferably 30 to 70°C.

[0148] Generally, best results are obtained by using three concentrator separators in series (or in series or in series), such concentrator separators having temperatures within the ranges given.

[0149] According to a preferred method, a portion of the fluid in liquid state concentrated in at least one concentration separator is sent to the pyrolysis reactor for recycling (or reuse or circulation). Preferably, the fluid recycled (or reused or circulated) to the reactor is obtained (or taken) from the first enrichment separator. Preferably, the concentrated fluid recycled (or reused or circulated) to the reactor is from 2% to 60% by weight, more preferably from 5% to 30% by weight, based on the weight of pyrolysis vapor produced. In one embodiment, the concentrated fluid, which may be recycled (or reused or circulated) to the reactor, is heated and then recycled (or reused or circulated).

[0150] The process for pyrolysis of a substantially plastic material to obtain at least liquid hydrocarbons (those that are in a liquid state at 25° C.), according to the present invention, may therefore preferably also comprise the following step (or step) (f): (f) A step (or a step) of recycling (or reusing or circulating) a part of the fluid (or fluids) in a liquid state, including liquid hydrocarbons (those in a liquid state at 25°C concentrated in the pyrolysis reactor in step (or step) (e)).

[0151] To facilitate pressure regulation, the applicant has found that it may be advantageous to pressure regulate a fluid in a gaseous state (hereinafter defined as an auxiliary gaseous fluid) for introduction into the reactor.

[0152] The auxiliary gaseous stream may be supplied (or fed) to the pyrolysis reactor, or may be supplied (or fed) to a device in fluid connection with the pyrolysis reactor (e.g., a preheating device).

[0153] It has further been observed that the supply (or feed) of fluids in gaseous state makes the start-up (or start-up) of a plant (or factory) simpler and faster.

[0154] Such auxiliary gaseous fluids, if provided, preferably have a mass flow rate of 1% to 50% of the vapor flow rate of the pyrolysis, even more preferably a mass flow rate of 2% to 30% of the vapor flow rate of the pyrolysis, and especially preferably a mass flow rate of 3% to 20% of the vapor flow rate of the pyrolysis.

[0155] In certain embodiments, the auxiliary gaseous fluid comprises a gas that is inert (or an inert gas) at the reaction conditions of the pyrolysis. Such inert gases preferably consist of nitrogen, carbon dioxide, water vapor, argon and relative mixtures.

[0156] In a preferred embodiment, the auxiliary gaseous fluid also includes, in combination or alternatively, natural gas and / or other light hydrocarbons. Particularly preferred is methane or mixtures of C1-C2, C1-C2-C3 or C1-C2-C3-C4 (where the numbers represent the number of carbon atoms). Advantageously, by using an auxiliary gaseous stream comprising natural gas and / or other light hydrocarbons, the remaining gas (or residue or residual) after concentration of the liquid hydrocarbons (those that are liquid at 25°C) can be more easily used and / or sold as fuel gas or as gas to supply a cracking plant (or cracking plant or cracking factory).

[0157] In certain embodiments, the auxiliary gaseous fluid may comprise, in combination or alternatively, a portion of the residual gas (i.e., as defined above and obtained after the pyrolysis vapors have passed through at least one condensation separator) (which, as previously reported, contains a large amount of hydrocarbons).

[0158] In certain embodiments, the auxiliary gaseous fluid may include, in combination or alternatively, water vapor. Indeed, it has been surprisingly found that the use of water vapor contributes to reducing fouling, especially at low flow locations (or points) of the reactor.

[0159] Moreover, it easily condenses and separates the water vapor from the concentrated liquid hydrocarbons (which are liquid at 25°C) downstream of the pyrolysis reactor, thus facilitating the start-up and pressure regulation of the plant, while at the same time avoiding the dilution of the remaining gases after condensation by water vapor (itself). This facilitates its use as fuel gas and / or sale and / or supply to cracking plants (or cracking plants or decomposition plants).

[0160] Therefore, a process for pyrolysis of a substantially plastic material to obtain at least liquid hydrocarbons (those that are in a liquid state at 25° C.) is a preferred method according to the present invention, said process also comprising the following step (or step) (a2): (a2) The step of supplying an auxiliary gaseous stream to the pyrolysis reactor.

[0161] The auxiliary gaseous fluids are as already explained above and preferably include inert gases (or inert gases) (preferably nitrogen, carbon dioxide, argon, water vapor and relative mixtures), natural gas and / or other light hydrocarbons (preferably methane, C1-C2, C1-C2-C3 or C1-C2-C3-C4 mixtures), residual gases (or gases) and relative mixtures.

[0162] Any technique known in the art can be used to adjust the pressure in the pyrolysis reactor in relation to the composition of the substantially plastic material and / or the composition of the products of the pyrolysis process. According to a first method, the pressure is adjusted by adjusting the heat extracted from a condensation separator located downstream of and in fluid connection with the reactor. In this mode (or form or embodiment), increasing the heat removed from the condensation separator results in greater condensation of the steam (or vapor). This greater concentration causes a greater amount of pyrolysis vapor to transition from gaseous to liquid state. The liquid state of a substance typically has a significantly greater density than the gaseous state. This bulk concentration therefore results in a reduction in the total volume (or capacity or volume or volume) occupied by the sum of the liquid and gas phases (or overall volume). Such capacitance is the physical capacity (or volume or capacity) of a device that contains fluid and cannot allow the fluid to be removed, thereby reducing pressure. In fact, lower pressure corresponds to a lower density of vapor, thus allowing the liquid and vapor phases to occupy the capacity of the device. Conversely, by reducing the heat removed from the condensate separator, and therefore the condensate flow rate, vapor will build up and thus pressure will increase.

[0163] Any method known in the art may be used to adjust the output (or power) of the concentrating separator. For example, the flow rate, level or temperature of the heat transfer fluid flowing through the concentrate separator jacket may be altered (as described above).

[0164] In this mode (or form or embodiment), the large amount of non-condensable gases that may be present in the vapor (e.g., nitrogen) may make control difficult because the non-condensable gases inhibit condensation.

[0165] Therefore, it may be advantageous to remove non-condensable gases prior to or during the pyrolysis operation. One way to eliminate the gases that cannot be condensed is to use any system for removing the gases. Such gases can then be treated or combusted. The system may include a valve for regulating the flow rate of the removed gas (or gas). If the pressure in the pyrolysis reactor is subatmospheric, the system may also include a suitable vacuum pump or other device for increasing the pressure of such gas (or gas). Optionally, a distillation column may be provided to concentrate the condensable hydrocarbon fraction, or alternatively or in combination, a gas stream removed from the condensed liquid may be concentrated.

[0166] In a preferred method, removal of such non-condensable gas(es) proceeds by removal of residual (or residual or remainder or residue) gas(es) (generated as described herein and illustrated by stream (59) in FIG. 4).

[0167] Gases that cannot be condensed (including auxiliary gases that can be used to pressurize) can be sent to a thermal oxidation system and then released to the atmosphere.

[0168] According to a second pressure regulation mode, the pressure is regulated by adjusting the flow rate of the auxiliary gas (or gas) (or auxiliary gas). For example, referring to Figure 5, this can be accomplished by a pressure regulating valve (77) that adjusts the flow rate of the supplemental gas (51) at the inlet to the pyrolysis reactor (70) based on a signal (84).

[0169] Advantageously, the two above methods can be combined and used together.

[0170] According to a third pressure regulation mode (hereinafter defined as pressure regulation mode for managing the pyrolysis vapors), the pressure is regulated by adjusting the opening of a valve through which the pyrolysis vapors pass and then enter at least one enrichment separator. For example, and referring now to FIG. 5, such adjustment may be accomplished by a signal (or signals) (85) sent to valve (72).

[0171] In this mode (or form or aspect), the valve allows for softer (smoother) regulation (or management or control) of the flow as the actuator position is varied, making such a valve particularly advantageous. This allows the process to be more stably controlled, especially during plant start-up, when the pyrolysis steam production, which is initially very small, can be increased very rapidly. A Vee-Ball valve can be used for this purpose.

[0172] Also, in the pressure regulation mode to control the pyrolysis vapors, the use of an auxiliary gas (or gas) is particularly useful, as already mentioned, to facilitate pressure control.

[0173] According to a fourth pressure regulation mode (hereinafter defined as the control mode of pressure regulation of the residual gas), the pressure is regulated by adjusting the opening of a valve through which the residual gas passes. As already mentioned, the residual gas consists of the fluid containing hydrocarbons that has not been enriched after passing through at least one enrichment separator. 5, for example, this occurs by adjusting a signal (87) sent to valve (76), which adjusts the flow rate of remaining gas outlet (59).

[0174] Advantageously, these two control systems (or management systems or control systems) (regulation of the power (or output) of the concentrate separator and regulation of the pressure of the residual (or residue or remainder or residue) gas (or gas)) can be combined together. In these combined modes, the pressure regulation system may advantageously be set in a "split range" mode (as described above). For example, if the regulator output can range from 0 to 100, it may be set to temporarily increase the cooling power to the condensation separator by increasing it by 0 to 50 (e.g., by removing heat from the liquid by increasing the liquid flow rate). On the other hand, the opening of the pressure regulation valve for the remaining gas (or residue) can be increased for a period of time by increasing it by 50 to 100 (i.e., keeping the valve closed at a value below 50, and then opening it completely at 100) to keep the cooling power (or cooling output or cooling force) unchanged (or kept constant).

[0175] According to the fifth pressure regulation mode (hereinafter referred to as the double pressure regulation control mode), the pressure is regulated by combining a pressure regulation mode for controlling the pyrolysis vapor and a pressure regulation control mode for the remaining gas. In this case, it may also be advantageous to feed in an auxiliary gas (or auxiliary gas) according to the method described above.

[0176] According to a fifth pressure regulation mode, it is also possible to set not only the pressure of the pyrolysis reactor, but also that of at least one enrichment separator located downstream thereof. In this way it is also possible to independently regulate the pyrolysis reactor pressure and the condensation pressure. This allows the reactor pressure to be maintained in accordance with the techniques of the present invention, and at the same time allows the condensation pressure to be adjusted, thereby maximizing the yield of the desired product.

[0177] All of the described pressure regulation modes may allow for dynamic adjustment of the set pressure valve. It is therefore possible to change the reactor pressure valve in a short time. Therefore, preferably the pressure in the pyrolysis reactor is not maintained constant, i.e., actively operated, so that this parameter is within a desired range, but is not constant, because the desired pressure range may vary. Preferably, the desired range is close to the target value, for example close to ±0.4 bar of the target value (i.e. the pressure falls within said desired range when the value is greater than or equal to -0.4 bar (or minus 0.4 bar) of the target value and at the same time the value is less than or equal to +0.4 bar (or plus 0.4 bar) of the target value).

[0178] Applicant has also surprisingly found that the pressure control mode disclosed in the present invention can not only dynamically adjust pressure, but can also be self-stable. "Self-stable regulation" means that, when properly tuned, a regulator responds to variations in a set point or to variations in an uncontrolled variable (such as more / less production of pyrolysis steam due to a change in the mixture of plastics contained in a substantially plastic material fed to pyrolysis) to limit the amplitude of oscillations over time.

[0179] It is therefore an object of the present invention to provide a process (or step or treatment or method) for pyrolysis of a substantially plastic material, in which in step (d) the pressure in the pyrolysis reactor is regulated by one or more of the following: - regulation of the heat extracted from a condensation separator arranged downstream of the reactor and in fluid connection therewith, preferably by regulating the power of the condensation separator, by removing non-condensable gases or by a combination thereof: - when supplying an auxiliary gaseous fluid, adjusting the flow rate of this auxiliary gaseous fluid; - controlling the pressure regulation of the pyrolysis steam by adjusting the opening of a valve through which the pyrolysis steam passes and thereafter into at least one condensation separator; - controlling the pressure regulation of the residual gas (or residue) by adjusting the opening of a valve so that the residual gas (or residue) passes through the valve and the residual gas (or residue) consists of a fluid containing the hydrocarbon(s) that has not been enriched after passing through at least one enrichment separator; - Dual control of pressure regulation in which a control mode for regulating the pressure of the pyrolysis vapours is combined with a control mode for regulating the pressure of the residual gas (or residue).

[0180] The pressure in the reactor is preferably maintained within the range between atmospheric pressure and 13 bar(a) (absolute). More preferably, the pressure is maintained within the range between 1.1 and 8 bar(a) (absolute). Even more preferably, the pressure is maintained within the range between 1.5 and 6 bar(a) (absolute). Most preferably, the pressure is maintained within the range between 2.5 and 4 bar(a) (absolute).

[0181] The pressure in the reactor can be measured in any manner known in the art. For example, a pressure transducer located inside the reactor may be used. Alternatively, according to a preferred method, when an auxiliary gaseous fluid is used, the pressure sensor may advantageously be located in the injection duct (or in the injection tube or in the injection duct) of the auxiliary gaseous fluid, and even more preferably near the inlet (or entrance) of the reactor. This makes it possible to limit the fouling of the sensor, since it remains in contact with the auxiliary gas fluid and does not foul it, and at the same time makes it possible to measure the pressure in the reactor, since the sensor is located close to the inlet part (or entrance) of the reactor. If such a duct (or tube) has a sufficiently large cross-sectional area (which may generally be only 1 / 100 to 1 / 10 of the reactor diameter), the kinetic losses of the gas (or gas) leaving the duct and entering the reactor are negligible, so that the pressure measured in the duct (or tube) will substantially match the pressure in the reactor. Also, more pressure sensors may be used to measure pressure more accurately and for greater reliability (or accuracy or reliability). According to one embodiment, when at least n (n≧3) measuring elements are provided, the pressure in the reactor corresponds to the average of n-1 measuring elements, where the measurement difference is the smallest.

[0182] Advantageously, the pressure regulation is performed by a controller, which can read the value of said pressure for at least one parameter (such as those already disclosed above) of at least one plant component (or element) (or plant element), compare said pressure value with a set value (or set point), and act by feedback or by forward control (or feed forward) or by a combination (or composition) of these two actions (feedback + feed forward). The purpose is to bring the difference between the two values ​​in absolute value from zero (in any case) to a value below a fixed value (for example below 0.4 bar). For this purpose any process controller can be used, for example a PID logic controller, a fuzzy logic controller, particle swarm optimisation (PSO) or a neural network, or a combination thereof, for example an integrated PID and fuzzy logic controller.

[0183] Preferably, such regulation is accomplished using a PID (proportional, integral, derivative) algorithm (either in the form of position (Position PID) or velocity (Velocity PID)).

[0184] Typically, when the pressure set value (or set point or set point) is changed, the adjustment mechanism (or regulation mechanism or regulation mechanism) disclosed above allows the new set value (or set point or set point) to be achieved in a short period of time. However, it may be preferable to avoid rapid pressure changes to avoid entrainment, fouling and instability in the pyrolysis process. Preferably, the ratio of the change in pressure set point (or set value) / time to reach a new set point (or set value) is greater than or equal to 0.1 bar / hour, more preferably between 1 and 120 bar / hour.

[0185] Typically, when the pressure setpoint (or set point or set point) is changed, the change in the operating point (OP) is essentially temporary. That is, the change in the operating point (OP) of the controller is temporary. However, after a time necessarily determined by the inertia of the system and by the constants of the regulator, the operating point (OP) returns to near the operating point (OP) before the change even if the pressure change is not temporary (of course, this does not necessarily mean that the setpoint (OP) is not returned to its original value).

[0186] For example, if the quantity regulated by the regulator is the power (or output) of a concentrate separator, an increase in the setpoint pressure will result in a decrease in the power (or output) of the concentrate separator (e.g., if the concentrate separator is a flooding concentrator, the level (or height) of concentrate present therein will increase). This causes an increase in pressure because, as already explained above, less steam is concentrated. However, once the target pressure has been achieved, the regulator will first spontaneously lower the pressure below the operating point and then close the valve until a change occurs. In fact, if the pyrolysis vapor flow rate does not change, the time-averaged concentrator power cannot change either.

[0187] Also, the set value (or set point or set-point) of the pyrolysis pressure can be changed manually. Preferably, such set values ​​(or set points) are varied automatically by feedback or feedforward based on the quality of the liquid product obtained at 25°C, as previously described, or based on a suitable characteristic index of the substantially plastic material used.

[0188] Preferably, the liquid product (i.e., pyrolysis oil) condensed with pyrolysis vapours obtained according to the present invention and liquid at 25°C comprises at least 35% of a C5-C12 fraction and at the same time more than 3.5% of a C21+ fraction (hereinafter referred to as "C21+").

[0189] Preferably, the C5-C12 yield obtained according to the present invention is at least 30%, while the C21+ yield is at most 3%.

[0190] The applicant of the present invention has observed that it is advantageous to prescribe (or define) an overall index (hereinafter also referred to as "Overall Index", or "OI" for short). The Total Index (or Overall Index) is defined as the Carbon Index (CI) (as defined herein) multiplied by the H / C Index (as defined herein) divided by 10,000.

number

[0191] According to one embodiment of the present invention, the pressure in the pyrolysis reactor is adjusted in relation to the H / C index (or H / C idx) and / or the carbon index (CI) of the substantially plastic material.

[0192] In an embodiment of the present invention, according to a preferred method, the pyrolysis process is carried out at a pressure of at least a threshold pressure (PS) when the "total index" (OI) is 0.7 or more, and at a pressure below the threshold pressure (PS) when the "total index" (OI) is less than 0.7. Preferably, the threshold pressure (PS) is at least 1.5 bar(a) (absolute), even more preferably between 2 and 2.9 bar(a) (absolute), especially 2.5 bar(a) (absolute). Generally, best results can be achieved by such methods when the substantially plastic material has an inconstant composition.

[0193] Indeed, by applying this criterion to Examples 1-11 of the present application, a C5-C12 yield of at least 30% was obtained, while at the same time a C21 or greater (C21+) yield of greater than 3% was obtained. Furthermore, the C5-C12 fraction was also greater than 30%. The C21+ fraction was greater than 3%.

[0194] Preferably, the pyrolysis oil (or oils) obtained from the process according to the invention is a mixture containing more than 90% by weight of hydrocarbon(s), based on the total weight of the mixture.

[0195] Advantageously, the pyrolysis process according to the invention produces particularly useful products. For example, virgin naphtha is particularly suitable for steam cracking to produce monomers of industrial interest, i.e., can be used in the synthesis of polymers. This allows the plastics (or plastic materials or plastics) to be recycled (or reused or circulated) an infinite number of times ("closed loop recycling") (the advantages of this invention have been explained above).

[0196] Advantageously, the process, i.e. the object of the invention, may also be applied to substantially plastic materials that do not contain polymers containing oxygen atoms (as will be evident from the examples). In one embodiment, the mass of oxygen atoms of the substantially plastic material fed into the pyrolysis reactor is between 0.05% and 18%, preferably between 0.5% and 12%, and more preferably between 1.1% and 8%, by weight based on the total mass of the substantially plastic material fed.

[0197] In fact, it has been observed that when the substantially plastic material introduced into the pyrolysis reactor comprises a polymer containing oxygen atoms, in particular within the indicated ranges, the pyrolysis oil (or oils) (or pyrolysis oils) obtained by applying the process according to the invention contain an optimal amount of tetrahydrofuran (THF).

[0198] Advantageously, in the pyrolysis oil produced, tetrahydrofuran has solvent properties, which reduces fouling in processes using the pyrolysis oil produced. In this way, for example in plants using pyrolysis oils, the cleaning downtimes can be reduced, as for example in steam cracking plants using pyrolysis oils, the downtimes can be reduced by 10%.

[0199] As is evident from the examples described, the process according to the invention makes it possible to increase the tetrahydrofuran content compared to conventional processes, in particular by obtaining a pyrolysis oil containing an optimal amount of tetrahydrofuran for the abovementioned purposes.

[0200] Advantageously, the pyrolysis oil according to the invention preferably contains tetrahydrofuran (THF), the content of which is between 0.01% and 0.25% by weight, preferably between 0.07% and 0.19% by weight, based on the total weight of the pyrolysis oil.

[0201] It has also surprisingly been found that the pyrolysis oil obtained from the process according to the invention is characterized by low amounts of benzoic acid.

[0202] In large quantities, benzoic acid is actually very detrimental in processes using pyrolysis oils because it releases acidity, and is produced in large quantities when the substantially plastic material being fed to the process contains large amounts of non-vinyl polymers, such as polyethylene terephthalate (PET).

[0203] According to the current state of the art, various processes have been proposed both for recovering benzoic acid downstream of pyrolysis and for reducing its production by catalytic conversion (see, for example, Shouchen Du et al., “Conversion of Polyethylene terephthalate based waste carpet to benzene-rich oil through thermal catalytic and catalytic steam pyrolysis”, ACS Sustainable Chem. Eng. 2016, 4, 5, 2852-2860, April 11, 2016, doi https: / / doi.org / 10.1021 / acssuschemeng.6b00450).

[0204] On the contrary, the process according to the invention makes it possible to avoid such benzoic acid recovery processes, thereby providing a pyrolysis oil (or oils) that already contains low amounts of benzoic acid.

[0205] Advantageously, the pyrolysis oil according to the invention comprises benzoic acid in a content of less than or equal to 2% by weight, preferably between 0.01% and 1% by weight, based on the total weight of the pyrolysis oil.

[0206] It has also surprisingly been found that the process according to the invention is characterized by a reduced production (or generation or formation or production) of some non-linear alkene(s).

[0207] In general, alkene(s) are known to be undesirable in pyrolysis oils because they support fouling and reduce naphtha quality (e.g., as measured using the PONA or PIONA index).

[0208] Advantageously, the pyrolysis oil, i.e. the object of the present invention, is characterized by a content of isobutene (IUPAC name is 2-methylpropene) of less than or equal to 0.55% by weight, preferably between 0.15% and 0.3% by weight, based on the total weight of the pyrolysis oil.

[0209] According to a first modality, the process for pyrolyzing a substantially plastic material is preferably characterized by adjusting the pressure based on the composition of the substantially plastic material.

[0210] The composition of a substantially plastic material can be analyzed using in-line, on-line or off-line methods. Among the off-line methods, any analytical technique known in the art can be used. In particular, if one is interested in calculating the H / C index and the carbon index, this is sufficient to estimate the total amount of carbon and hydrogen contained in the substantially plastic material. For this purpose, for example, elemental analyzers can be used, by which a sample is completely combusted and the gases formed are subsequently analyzed by gas chromatography, thermal conductivity, infrared spectroscopy or a combination of these techniques.

[0211] Among other in-line or on-line methods, automated sampling systems connected to a gas chromatograph, a gas chromatograph connected to a mass spectrometer or a near-infrared (NIR) measurement system can be used.

[0212] According to different modalities, the process for pyrolyzing a substantially plastic material is characterized by adjusting the pressure based on a characteristic parameter defined by the composition and / or by the production yield of a fluid comprising liquid hydrocarbon(s) (which are in a liquid state at 25°C) and / or by its characteristic parameter.

[0213] The composition of the pyrolysis oil can be determined by in-line, on-line or off-line methods. In-line or on-line methods can be used, in particular automated sampling systems connected to a gas chromatograph or near-infrared (NIR) measuring systems. According to the invention, the pressure in the pyrolysis reactor is adjusted as a function of characteristic parameters defined by the composition of the substantially plastic material and / or by the product of the pyrolysis process, while simultaneously maintaining the pressure in the pyrolysis reactor at a value between atmospheric pressure and 13 bar(a) (absolute).

[0214] Preferably, the pressure is adjusted in relation to a characteristic parameter dictated (or defined) by the product (or product or product) of the pyrolysis process, the product (or product or product) being generated (or generated or formed or produced) in process (or step) (c) and / or process (or step) (e) of the process for pyrolyzing a substantially plastic material according to the present invention. According to one embodiment, the characteristic parameter defined by the composition of the substantially plastic material is the H / C index and / or the carbon index of the substantially plastic material.

[0215] According to one embodiment, the product (or product or process) of the pyrolysis process for which the characteristic parameters are specified (or defined) is a pyrolysis oil (or oils) obtained by condensation of the effluent (or effluent) in gaseous state produced (or formed) by the reactor in process (or step) (c) and / or a fluid (or fluid) comprising liquid hydrocarbon(s) (in liquid state at 25° C.) obtained from the condensation described in process (or step) (e).

[0216] According to one embodiment, the characteristic parameters defined by the product of the pyrolysis process are its production yield and / or characteristics measured on the product of the pyrolysis process, in particular refractive index, viscosity, molecular weight and relative combinations thereof.

[0217] According to one embodiment, the process for pyrolyzing a substantially plastic material is characterized in that the pressure is not constant. Preferably, the inconstant pressure is temporally inconstant, spatially inconstant, or both spatially and temporally inconstant.

[0218] When we say that the pressure is not temporally constant, we mean that the pressure fluctuates over a certain time domain (or time domain or time domain). Preferably, according to this method the temporary fluctuation (or variation) is at least 0.2 bar per day, even more preferably between 0.5 bar and 15 bar per hour, even more preferably between 1 bar and 5 bar per hour.

[0219] By pressure we mean that the pressure is not spatially constant, we mean that in a given spatial domain, the pressure is varied, i.e. by maintaining different zones of the reactor at different pressures. For example, at a certain pressure there may be a first zone of the reactor (wherein the reactor receives (or accepts) the substantially plastic material) and a second zone. In the first zone, a substantially plastic material is heated and maintained at a first pressure for a first residence time (or dwell time or residence time or residence time). In the second zone, the substantially plastic material (which has already been partially pyrolyzed) is maintained at a second pressure different from the first pressure for a second residence time (or dwell time or residence time or residence time).

[0220] According to this embodiment, the pressure difference between one zone and the next is preferably positive, i.e. the pressure in the next zone is less than the pressure in the previous zone. Preferably, the pressure difference between one zone and the next is at least 0.1 bar, more preferably between 0.2 bar and 10 bar, even more preferably between 1 bar and 5 bar, and most preferably between 2 bar and 4 bar.

[0221] Preferably, the process for pyrolyzing a substantially plastic material is characterized by a sufficient time (at least 30 minutes, preferably between 1 hour 30 minutes and 15 hours, even more preferably between 2 hours 30 minutes and 9 hours, and most preferably between 3 hours and 6 hours) to generate (or form) at least one effluent in gaseous (or gaseous) state in the pyrolysis reactor (as defined in process (or step) (c) of the process).

[0222] In a continuous or semi-continuous process (as defined above), the time (as defined in process step (c)) is calculated as the ratio of the reactor capacity (not occupied solely by gas phase) to the volumetric flow (or capacity flow rate or volumetric flow rate or volumetric flow rate) supplied. Volume flow (or volumetric flow rate) means the flow rate (or flow velocity or flow rate) per unit of volume (or volume or volume). Volume flow (or volumetric flow rate) may be calculated, for example, by dividing the mass flow (or mass flow rate) by the density of the substantially plastic material.

[0223] Capacity of a reactor (not occupied by the gas phase alone) means the capacity calculated by subtracting the capacity occupied by the gas phase alone from the geometric capacity of the reactor. Thus, following what has already been indicated above, the capacity (or volume or capacity) of the reactor (not occupied by gas phase) is the capacity (or volume or capacity) of the reactor that is below the "free surface", i.e. the capacity (or volume or capacity) of the reactor that is substantially occupied by the non-gaseous phase (as defined above). Generally speaking, the capacity (or volume) of such a reactor therefore includes the liquid and solid phases plus any evolved gas (which has not yet reached the free surface or liquid-gas separation surface).

[0224] The pyrolysis reactor may include further components (or components or elements) (e.g., at least one stirrer (or agitator)) and / or other components (or components or elements) (e.g., baffles, etc.). In this case, the geometric capacity (or volume or geometric volume) of the reactor means the geometric capacity (or volume or geometric volume) of the reactor minus the capacity (or volume or geometric volume) of the above-mentioned components (or elements or components or elements). In other words, the net capacity (or net volume or net volume or net volume) of the reactor.

[0225] If there is no free surface or no liquid-gas separation surface is formed (e.g. because it cannot be determined or because a foam forms at a level that fills the entire reactor), the above capacity should be considered as the geometric capacity of the reactor.

[0226] Instead, the volume flow (or capacity flow rate or volumetric flow rate or volumetric flow rate) of the substantially plastic material being fed into the reactor is expressed in SI units, e.g., m 3 It is expressed in / s and may be calculated either directly (the volume delivered (or fed) divided by the time (or duration) over which such volume (or volume) is delivered (or fed)) or indirectly, for example by measuring the mass flow and dividing it by the density.

[0227] On the other hand, in a batch process (discontinuous process), the time as specified (or defined) in step (c) above is calculated as the retention time (or hold time) of the material in the pyrolysis reactor under the conditions indicated in step (c) above.

[0228] In the pyrolysis process according to the present invention, the residence time (or residence time or residence time) is preferably at least 30 minutes, even more preferably from 45 to 540 minutes, even more preferably from 60 to 360 minutes, even more preferably from 90 to 240 minutes, and particularly preferably from 130 to 210 minutes.

[0229] Advantageously, the process for pyrolyzing a substantially plastic material may comprise an automatic regulation and control system for automatically regulating at least the pressure in process (or step) (c). In addition to the pressure in process (or step) (c), the automatic regulation and control system may also regulate other process parameters (e.g., the temperature and / or residence time in process (or step) (c)).

[0230] An automatic regulation and control system may be required for one or more process variables, including the pressure in process (or step) (d). Additionally, process variables may also include the process yield of liquid hydrocarbon(s) (that are liquid at 25° C.) described in process (or step) (e).

[0231] Alternatively or in combination, the automatic regulation and control system may involve one or more product variables. The product variable may be a characteristic of the substantially plastic material fed to the process (step (a)). For example, it may be the H / C index or the carbon index.

[0232] Alternatively or in combination, the product variable may be a characteristic of the gaseous effluent described in process step (c) and / or the liquid hydrocarbon(s) (liquid at 25° C.) containing fluid described in process step (e), selected from molecular weight, molecular weight distribution, halogen content, content of compounds having 5 to 12 carbon atoms (C5-C12), content of compounds having at least 21 carbon atoms (C21+), or a combination thereof.

[0233] Preferably, the mixture of hydrocarbon(s) obtained from the pyrolysis process disclosed in the present invention contains tetrahydrofuran in an amount between 0.01% and 0.25% by weight, more preferably between 0.07% and 0.19% by weight.

[0234] Preferably, the process for pyrolysis of substantially plastic material is integrated with a process for recovering plastic material including a sorting plant, such that the pyrolysis process uses the unrecovered fraction (as a single polymer) as the substantially plastic material fed in step (a).

[0235] Preferably, the effluent in gaseous form produced in step (c) may be further treated in a dedicated step (c2) followed by a partial or total concentration as described in step (e). Preferably, such further treatment (step (c2)) consists of subjecting the effluent to a certain temperature (between 400 and 650°C, preferably between 440°C and 550°C, even more preferably between 460°C and 530°C) and maintaining (or holding) the effluent at this temperature for a certain time (at least 10 seconds, preferably between 30 seconds and 6 minutes, even more preferably between 1 minute and 4 minutes).

[0236] Preferably, step (c2) is carried out in the presence of a solid catalyst in contact with the effluent in gaseous state. Even more preferably, such gaseous effluent is in relative motion with respect to the solid catalyst (catalyst in contact with the gaseous effluent). The velocity of such relative motion is at least 0.5 m / s, more preferably between 2 and 50 m / s.

[0237] According to one embodiment, the passage (or pass or route or step) (c2) is carried out at a pressure that substantially corresponds (or is equivalent) to the pressure used in the passage (or pass or route or step) (c). Substantially corresponding (or equivalent) pressure means that the difference between the pressure of the passage (or path or route or step) (c) and the pressure of the passage (or path or route or step) (c2) is preferably comprised between zero (0) and 0.5 bar.

[0238] According to an alternative embodiment, the passage (or pass or route or step) (c2) is carried out at a pressure substantially lower than the pressure used in the passage (or pass or route or step) (c). Substantially lower pressure means that the difference between the pressure in the passage (or path or route or step) (c) and the pressure in the passage (or path or route or step) (c2) is greater than 0.5 bar. To carry out such an alternative embodiment, a pressure regulating valve can be placed between the reactor for pyrolysis and the reactor in which step (c2) is carried out. In this embodiment, the pressure in the pyrolysis reactor may be regulated through a pressure regulating valve.

[0239] According to one embodiment, the passage (c2) is carried out at atmospheric pressure.

[0240] Any catalyst known in the art may be used as the solid state catalyst, including certain zeolites.

[0241] The present invention also relates to a reactor for the pyrolysis of a substantially plastic material, the purpose of which is to obtain at least liquid hydrocarbon(s) (which are in a liquid state at 25° C.), comprising: (i) to (viii) a reactor for the pyrolysis of a substantially plastic material; (i) At least one port (N2) for exiting a gaseous product, the port (N2) being located at the top of the reactor or at a distance from the top of the reactor, the distance being less than or equal to 1 / 3 of the height (H) of the reactor; (ii) At least one port (N3) for removing a solid product, located at the bottom of the reactor or at a certain distance from the bottom of the reactor, such distance being not more than 1 / 3 of the height (H) of the reactor; (iii) At least one port (N1) for admitting a substantially plastic material, the port (N1) being at a certain distance (D1) from the top of the reactor, such distance (D1) being equal to or greater than the distance (D2) between the port through which the gaseous product (or product) exits and the top of the reactor, (iv) At least one stirrer (or agitator); (v) at least one jacket for heating the reactor, (vi) at least one temperature transducer; (vii) at least one pressure transducer; (viii) At least one sensor for measuring the level (or height) of the reactor wherein the reactor is characterized in that there is a separator (demister) for carry-over (or remaining or remaining) material placed below the port for the exit of the product of said gaseous (or gaseous) and / or at the port for the exit of the product of said gaseous (or gaseous) Also, according to one embodiment, the reactor is characterized by a design pressure (or specified pressure or set pressure or design pressure or design pressure) of at least 2 bar (absolute (a)) and a design temperature (or specified temperature or set temperature or design temperature or design temperature) of at least 450°C. Also, according to one embodiment, the reactor is characterized by a concave volume (or a concave or concave surface or concave capacity or volume or volume) which is 10% or more of the total volume (or total capacity or total volume) of the reactor.

[0242] This reactor may advantageously be used to carry out steps (or steps) (a) to (d) of the process according to the invention.

[0243] Typically, reactors for the pyrolysis of substantially plastic materials suffer from a problem of fouling, which reduces their operability. Indeed, fouling is typically constituted by carbon deposits, which tend to adhere and accumulate on the inner surfaces of the reactor. As a result of the accumulation of fouling, the system becomes more difficult to manage. Furthermore, it has been observed that fragments of the fouling material may detach from the inner walls of the reactor and become entrained in the pyrolysis vapors, thus resulting in concentrated pyrolysis oil. It is therefore necessary to interrupt the process, clean the plant, open the reactor and clean the reactor, for example by brushing or hydro-jetting. Frequent fouling is therefore undesirable and can result in reduced plant (or factory) productivity.

[0244] Furthermore, fouling tends to cover not only the inner surfaces of the reactor, but also temperature, pressure and level (or height) sensors, thus reducing their efficiency.

[0245] This loss of efficiency is especially severe for pressure sensors because, in accordance with the present invention, the reactor pressure is regulated and therefore inaccurate measurement of the reactor pressure can jeopardize the results.

[0246] Finally, it has also been observed that pressure fluctuations favor fouling when the pressure changes rapidly. Without wishing to explain this phenomenon, rapid pressure variations can cause fouling, since during the rapid pressure drop the volume of the gas bubbles is substantially contained within the non-gas phase, and some of the liquid present therein can evaporate. Thus, foaming may occur and the presence of liquid, molten and solid materials subsequently wets those parts of the reactor that would normally be in contact with only the gas phase. During subsequent pressurization stages or by stabilization of the sample, the bubbles (or foam) will decrease, but some of the reactor surfaces will remain wetted with liquids, melts and solids (unlike the lower part of the reactor, which is wetted by substantially non-gaseous phases), and such liquids, melts and solids cannot be removed or replaced by other materials, because they remain in contact with only the gas phase.

[0247] It has been observed that a reactor for pyrolysis of a substantially plastic material to obtain at least liquid hydrocarbon(s) (which are in a liquid state at 25° C.), comprising the features described above, can surprisingly reduce fouling during the pyrolysis process or according to the method presented in the present invention, even when the pyrolysis pressure fluctuates.

[0248] In particular, the location (or location or position) of the ports, as shown, along with a substantially convex (or convex or convex) profile (or shape) have been observed to be important features (or characteristics) for achieving the above results, as also shown by the examples of the present invention.

[0249] Such a reactor further includes a demister, which is disposed below and / or at the port through which the gaseous product exits.

[0250] The demister avoids carry-over of substantially plastic material as well as liquids (resulting from the partial pyrolysis of the substantially plastic material) with the pyrolysis vapors.

[0251] It has further been discovered that the demister can retain (or hold back) liquid that forms during pressure changes. Indeed, the process according to the invention is characterized by non-constant pressure. If the pressure is increased (e.g., due to a variation in the nature of the substantially plastic material at the inlet of the reactor as described below, or via feedback regarding the viscosity, refractive index or molecular weight of the liquid hydrocarbon (that is liquid at 25°C) being produced), the sudden formation of liquid droplets may occur. The demister thus facilitates reducing the amount of liquid droplets (or droplets) that are entrained (or entrained) with the pyrolysis vapors.

[0252] Conversely, if the pressure decreases too quickly, boiling may occur in the liquid contained in the pyrolysis reactor. Since this liquid contains the polymer being pyrolyzed, such sudden boiling can cause a temporary increase in the level in the reactor, especially if the liquid phase is viscous, since the bubbles that form take some time to reach the surface of the reactor. This level (or height) may be increased to a point where it fills the entire pyrolysis reactor. In this case, the fluid (which is in liquid state) containing the polymer being pyrolyzed may reach the vapor outlet nozzle and be withdrawn, with the resulting harmful fouling and malfunction of pressure control equipment and systems.

[0253] It has therefore been found that the demister can promote not only the association of droplets in an air stream, but also the separation of the gas phase entrained in the liquid. Thus, at the outlet for pyrolysis vapor, a liquid phase is prevented from being taken out together with the gas phase.

[0254] According to a preferred method, several (or multiple) pyrolysis reactors may be used to carry out steps (a) to (d) of the process according to the invention, the pyrolysis vapours therefrom being fed to a single second reactor (or single secondary reactor) carrying out step (c2) as described above. In such a mode, the vapor from the pyrolysis reactor may be stored and then entered into the second reactor or through a separate outlet. Advantageously, an interception valve may be inserted for each of the pyrolysis vapours emitted from each pyrolysis reactor, making it possible to operate the plant even during maintenance, malfunctions and / or operations of loading substantially plastic material and / or discharging solid residue in one of the pyrolysis reactors.

[0255] (Preferred mode (or form or embodiment) of the reactor according to the present invention) According to a preferred method, the height (DJ) is greater than or equal to the distance (D1). The height (DJ) is the height corresponding to the distance from the top (or upper part or apex) of the reactor to the highest point (or point) of the body (or main body) of the reactor that is heated by the jacket. The distance (D1) is the distance between the port where the substantially plastic material enters and the top (or upper portion or apex) of the reactor.

[0256] By "highest point" of the reactor body heated by the jacket is meant the highest point of the reactor body in contact with the heat transfer fluid circulating within the jacket (as shown in FIG. 1).

[0257] Preferably, the jacket for heating the reactor has a minimum distance from the top (or upper part or apex) of the reactor, such distance being greater (or longer or higher) than 1 / 3 of the height of the reactor.

[0258] Preferably, the reactor heating jacket includes a septum (or partition) which promotes (or is advantageous to) a uniform distribution of the heat transfer fluid circulating inside it. Alternatively, the reactor heating jacket is a coil, such as a coil made of a tube that wraps around the wall of the reactor. According to a further modality, the jacket for heating the reactor is a coil, such coil being made from a half-pipe (i.e. a pipe cut in half along a plane passing through the diameter of the pipe, perpendicular to the cross section of the pipe) and welded to the wall of the reactor. This kind (or type) of jacket is known as a "half-pipe jacket" or "split coil jacket".

[0259] According to a first method, the heat transfer fluid inlet is positioned at the bottom of the jacket and the outlet is positioned at the top of the jacket, thereby creating a flow from the bottom upwards of the jacket. This mode (or configuration or aspect) promotes (or is advantageous) the outflow of bubbles contained in the heat transfer fluid. Alternatively, the heat transfer fluid inlet is positioned at the top of the jacket and the heat transfer fluid outlet is positioned at the bottom of the jacket, thereby achieving a top to bottom flow of the jacket. This mode (or form or aspect) is particularly useful when using molten salt as the heat transfer fluid, meaning that no dedicated pump is required, since the heat transfer fluid can be forced into the jacket by using gravity force. Advantageously, in this case, the heat transfer fluid may be at substantially atmospheric pressure.

[0260] According to a preferred method, the stirring elements (or agitation elements) are placed at a distance (DS) from the top (or upper or apex) of the reactor, the distance (DS) being equal to or greater than the distance (D1), the distance (D1) being the distance between the port for admitting the substantially plastic material and the top (or upper or apex) of the reactor. By stirring element (or stirring element) is meant a stirring component (or structure or element or element) that contributes to the stirring effect (or stirring effect), i.e. the rotational movement about the axis of rotation of the substantially non-gaseous phase (or non-gaseous phase) present in (in) the pyrolysis reactor. Thus, a stirring element (or stirring component) may be a stirring barrel, but not a stirring shaft, bushing, or other component (or structure or element or element) that does not contribute to imparting rotation.

[0261] According to a preferred modality, the reactor further comprises: (ix) and / or (x) (ix) At least one port for admitting an auxiliary gaseous fluid at a distance from the top of the reactor, the distance being no greater than 1 / 3 of the height of the reactor; and / or (x) At least one port for admitting liquid fluid that is concentrated in at least one concentration separator and recycled (or reused or circulated) in the reactor, said port being located at a distance from the top (or upper portion or apex) of the reactor, said distance being not more than 1 / 3 of the height of the reactor. Particularly preferred is a reactor comprising: (x) (x) At least one port for admitting the concentrated liquid fluid to at least one concentrate separator.

[0262] According to a preferred embodiment, the reactor comprises at least one system for regulating the pressure in the reactor with respect to one or more characteristic parameters of the substantially plastic material fed and / or of the pyrolysis oil produced by the reactor.

[0263] As stated, the reactor according to the invention is characterized by the presence of a demister. Any kind (or type) of demister known in the art may be used. For example, a suitable net (or screen) may be used that is located at the top (or upper part or apex) of the reactor, but below the port through which the gaseous product (or product) exits. Such a net (or mesh) may be made (or formed) from woven (diagonal folded) metal wire ("diagonal crimped knitted wire") (e.g., 0.011 inch). Alternatively, multiple bars may be used at the same position, arranged to impinge on the flow of vapor toward the pyrolysis vapor outlet port according to methods known in the art.

[0264] Such bars are particularly useful for the action of liquid-gas separation (or gas-liquid separation) in the case of rapid decompression, as described above.

[0265] According to an alternative embodiment, the demister may be of a type having a compartment with one (or single) or two (or double) pockets ("single pocket vane" or "double pocket vane") (with horizontal or vertical flow). Of these types, the vertical flow single pocket system is preferred.

[0266] Preferably, the demister comprises a cyclone, which is present within the reactor and is characterized by having a gas outlet (or outlet) (or gas outlet or gas outlet or gas outlet). The gas outlet (or outlet) is connected to a port for exiting steam (or vapor) from the pyrolysis reactor.

[0267] Referring to FIG. 2, the entrainment separator (or entrainment separator or entrainment separator) includes a body (21) having a substantially cylindrical portion (or section), the body (21) having a first opening (or aperture or opening) (22), a second opening (or aperture or opening) (23), and a sleeve (24). a first opening (22) to admit steam (or vapor) of pyrolysis entrained with liquid and / or solids (if present); a second aperture (23) to allow separated liquids and / or solids to exit; A sleeve (24) allows the vapors of pyrolysis to escape the reactor through port (N2).

[0268] The cyclone is therefore characterized by an inlet (22) which is preferably off-axis so as to impart a tangential motion to the vapor entering the body of the cyclone (21). The cyclone includes a "vortex finder" that includes an opening (24) that picks up the pyrolysis vapors and conveys them toward the outlet of the reactor. The cyclone also has an opening at its bottom (23) that allows the collected liquid to escape, so that it can fall back into the reactor under its own gravity.

[0269] Advantageously, the opening (or aperture) at the bottom (or lower part or base) (23) is characterized by a cross section of its passage (or path or route or step) which is no more than 20%, preferably no more than 10%, and even more preferably no more than 5% of the cross section of the passage (or path or route or step) at the inlet (or entrance) (22).

[0270] Preferably, the cyclone is entirely contained within one third (1 / 3) of the height H of the reactor, i.e., its lower end is at most H / 3 away from the top (or upper or apex) of the reactor (always measured along the vertical direction). Of the various demister modes described, the cyclone mode has generally proven to be the best due to the reduced occurrence of fouling and ease of maintenance.

[0271] The analytical techniques used in the examples of the present invention are described in detail below.

[0272] (Method of analysis by gas chromatography of samples (or specimens) of pyrolysis oil (or oils)) The pyrolysis oil sample was characterized by gas chromatography analysis. First, the compounds were quantitatively identified by a technique combining gas chromatography and mass spectrometry (GC-MS), while the compounds were quantified by gas chromatography with a flame ionization detector (GC-FID).

[0273] The instrument parameters used in the GC-FID analysis were as follows: - GC: Agilent HP 7890 B (fitted with a Gerstel MPS autosampler) - Column: HP-PONA Agilent Technologies J&W-50m-0.2mm-0.5μm - Carrier (H2): 1.1mL / min (constant flow) - Injector: 350℃, 255:1 split, 3mm (Ultra Inert) (liner (with glass wool)) - Detector (or detector): 360°C - Oven: Column temperature program: 20°C 5 min, 2°C / min (max 70°C, 5 min), 2°C / min (160°C, 5 min), 2°C / min (up to 320°C, 30 min) (run time: 195 min)

[0274] Samples were analyzed individually, with arbitrary response factors (or response coefficients or response factors) assumed to be equal to 1 for all compounds, and the concentrations obtained were then normalized (100%).

[0275] (Mode (or form or aspect) of analysis of gas chromatography (wax sample (or waxy sample))) Wax means the bottom fraction remaining after centrifuging the pyrolysis oil (as described below).

[0276] This fraction (or fractions) is analyzed in various ways, so that the high molecular weight compounds (or polymeric compounds) can be identified as well.

[0277] In fact, in gas chromatographic analysis, these compounds could not be conveniently eluted and analyzed.

[0278] Prior to taking the sample for GPC analysis, the pyrolysis oil was contained in a Schott bottle and its contents were homogenized by heating to 50°C (in some cases characterized by a deposit and / or layer of waxy compounds at room or chilled temperatures). A few milligrams of sample (in 1,2,4-trichlorobenzene (Baker) with 10 μL of n-heptane (internal marker)) was dissolved by heating (150 °C for 1 h), resulting in a concentration of about 1.8 mg / mL.

[0279] The analysis was carried out using the following chromatographic equipment: - High temperature Char Polymer GPC-IR - 3 TSK gel HT2 columns (dimensions: 13 μm) and a pre-column Bench - IR5 high temperature infrared detector The detector provides an absorbance signal (or signals) that is proportional to the amount of methyl and methylene groups.

[0280] The experimental conditions applied were as follows: - Eluent: 1,2,4 TAB (stabilized with BHT) - Flow: 1mL / min - Temperature: 25°C (pump), 150°C (or injector), 150°C (column), 150°C (detector) - Injection volume: 200 microliters (μL) - Internal standard: n-heptane

[0281] (Analysis of pyrolysis gas (or gases) by gas chromatography) A sample of the pyrolysis gas effluent was collected in a 500 mL Swagelok cylinder (DOT type) (i.e., regulated by the US Department of Transportation (DOT)) (stainless steel type 304L, internally coated with PTFE to render the interior surface inert). The instrument used was an Agilent 490 μGC with three modules in parallel, each of which determined only a particular class (or type) of compounds. Details are as follows: - Module 1: 10m MS 5Å (with injector heating, backflush) - Module 2: 10m PPQ (no injector heating) - Module 3: 10m CpSil-5CB (with injector heating)

[0282] The instrument parameters used in the various modules are as follows: - Module 1: Injector: 110°C, Backflush: 30s, Injection time (or injection time): 100ms, Column: 45°C, Carrier gas pressure: 80kPa, Carrier gas: Argon (required for hydrogen analysis) - Module 2: Injection time (or injection time): 15 ms, Column T: 70°C, Carrier gas temperature: 180 kPa, Carrier gas: Helium - Module 3: Injector: 110°C, Injection time (or injection time): 20 ms, Column: 70°C, Carrier gas pressure: 230 kPa, Carrier gas: Helium

[0283] Analysis of each module (only for a few specific compounds) - Module 1: Hydrogen, Oxygen, Nitrogen, Methane, CO - Module 2: CO2, ethylene, ethane, propylene, propane, propadiene, propyne, i-butane, i-butene, 1-butene, 1,3-butadiene, n-butane, trans-2-butene, cis-2-butene - Module 3: 1-butene-3-yne, 1,2-butadiene, i-pentane, 1,4-pentadiene, 1-pentene, n-pentane, 2-methyl-2-butene, 1,3-pentadiene, cyclopentene, n-hexane, methyl-1,3-cyclopentadiene, benzene, 3-ethylcyclopentene, methylcyclohexane, toluene, ethylbenzene, xylene

[0284] Quantification was performed by a calibration line using an external standard. It consists of two calibration cylinders with the following composition: - Cylinder 1: pentene-2(trans) = 0.1 mol%; pentene-2(cis) = 0.1 mol%; pentene-1 = 0.1 mol%; pentane-n = 0.25 mol%; methyl-2 Butene-2 ​​= 0.2 mol%; isopentane = 0.5 mol%; hexane-n = 0.1 mol%; propylene = 20 mol%; propane = 0.5 mol%; propadiene = 0.5 mol%; methane = 20 mol%; isobutene = 1 mol%; isobutane = 0.5 mol%; hydrogen = 15 mol%; ethylene = 30 mol%; ethane = 3 mol%; carbon oxide = 1 mol%; carbon dioxide = 0.5 mol%; butene-1 = 1 mol%; butene-2(trans) = 0.5 mol%; butene-2(cis) = 0.5 mol%; butane-n = 0.5 mol%; butadiene-1,3 = 1.5 mol%; acetylene = 0.5 mol%; balance (up to 100%): nitrogen Cylinder volume [liters]: 40; Charging pressure (or filling pressure) [bar]: 6.29; Cylinder type: Aluminum - Cylinder 2: Benzene = 0.0302 mol%; Toluene = 0.0323 mol%; Methycyclohexane = 0.0674 mol%; Styrene = 0.0334 mol%; Ethylbenzene = 0.0339 mol%; Remainder (to 100%): Helium Cylinder volume [liters]: 5; Charging pressure (or filling pressure) [bar]: 13.9; Cylinder type: Aluminum

[0285] The calibration cylinder does not contain the following compounds, so we used compounds that are sufficiently similar to them (compounds with very similar response factors) (in this case, the differences can be ignored).

[0286] [Table 1]

[0287] (Thermo-Gravimetric Analysis (TGA) method for solid residue (char)) TGA analysis was performed using a TA Instrument model Q 500 instrument. A temperature calibration was performed (using Alumel Curie Points and nickel samples), while a weight calibration was also performed (using the certified weights supplied by TA Instruments with the analyzer). The sample (or specimen) (weighed in an amount of 20-30 mg in a stainless steel sample holder) was placed directly, together with the sample holder, in a platinum crucible in the TGA analyzer. The use of a stainless steel sample holder facilitates the isolation and recovery of the final residue (ash) while preserving the integrity of the platinum crucible. The samples (or reagents) were subjected to the analytical procedure (or procedure) in three stages: - 1st stage (pyrolysis under nitrogen atmosphere): Starting from an initial temperature of 40° C., the sample (or specimen) was heated at a controlled rate (v=10° C. / min) up to 800° C. - Second stage (cooling under nitrogen): Starting from an initial temperature of 800° C., the sample (or specimen) was cooled at a controlled rate (v=20° C. / min) to 400° C. - Third stage (thermal oxidation in air): Starting from a temperature of 400° C., the sample (or specimen) obtained by pyrolysis (stage 1a) was subjected to heating at a controlled rate (v=20° C. / min) up to 850° C.

[0288] Integration was performed using Universal software (TA Instruments). The results are shown below. - Stage 1: After the temperature is determined, the weight loss at various temperatures is correlated to the maximum peak of the derivative of the weight loss with respect to temperature and residue at 800°C. - Stage 3 After the temperature is determined, the weight loss at various temperatures is correlated to the maximum peak of the derivative of the weight loss with respect to temperature and residue at 850°C. For stage 3, the weight loss was correlated to one or more carbonaceous species (different allotropic states or particle sizes).

[0289] Some non-limiting examples of the present invention are given below.

[0290] (Method for determining ash (inorganic residue) in substantially plastic materials) 20 g (grams) of substantially plastic material was weighed into a crucible and placed in an oven (Heraeus model K1253, Tmax=1250° C.) maintained under nitrogen flow. The temperature was increased to 400° C. (ramp=5° C. / min) and maintained at 400° C. for an additional hour. Air was then supplied instead of nitrogen. The temperature was gradually increased to 850° C. (also ramp = 5° C. / min) and maintained at 850° C. for an additional hour. The oven was then shut off and allowed to cool over approximately 12 hours.

[0291] The remaining material, called ash, was weighed. The ash percentage (or percentage or %) was calculated as the weight of the residue (or remainder or residue) relative to the amount of material of the substantially plastic material originally weighed (20 g). EXAMPLES

[0292] (Example) raw material It was deemed appropriate to use primarily virgin raw materials, so that the composition is known and constant, thereby enhancing the reproducibility of the invention. Therefore, by preparing (or manufacturing or forming) a suitable mixture of raw materials, it became possible to evaluate the effect on pyrolysis (any variations in pyrolysis are due to this alone). A substantially non-new (or new or virgin) plastic material (or plastics material or plastic substance material or plastic material) (hereinafter referred to as "BA1") was also tested. Such materials are the remainder (or residue or residu) after selection ("sorting") of recycled (or reused or circulated) plastic materials ("Plasmix" type). Such materials were then analyzed according to that already presented to determine their atomic composition.

[0293] The materials used were as follows:

[0294] [Table 2]

[0295] Polyethylene granules were mixed in the following ratios: 5.7% HDPE Eraclene BC82 34.3% LLDPE Flexirene CL10 60% Riblene FC20 This mixture is therefore the "PE" material for subsequent use.

[0296] The table below shows the atomic composition of the materials used (% by weight).

[0297] [Table 3]

[0298] The "BA1" material also exhibited residual ash, essentially attributable to inert inorganic material, equal to about 4% by weight, as determined using the method described above.

[0299] The following compounds were prepared (or manufactured or formed) using the ingredients listed (parts by weight):

[0300] [Table 4]

[0301] Then, based on the carbon atom (or carbon atom) and hydrogen atom (or hydrogen atom) content (or content or content) of the raw material used (shown in the table above), the carbon index (CI) and H / C index (H / C index or H / C idx) can be calculated from the following formula.

number

number

[0302] Here, the sum is calculated for each material with which the compound is blended (or compounded). As used herein, "weight atomic" refers to the total mass of the indicated atom (or "all" total atoms) in the material. Therefore, for the five compounds used, the following H / C index (or H / C idx) and carbon index (CI) values ​​can be calculated from these formulas, while for the recycled materials (such as Plasmix BA1), the calculations were performed starting from the atomic composition shown above.

[0303] [Table 5]

[0304] From an analysis of the table, it is clear that PAT1 and PAT2 are formulations (or formulations or compounds) characterized by a high H / C index, and PAT3 and PAT4 are formulations (or formulations or compounds) characterized by a low H / C index. On the other hand, the carbon indices of PAT1 and PAT3 are high (both are 86), while the carbon indices of PAT2 and PAT4 are low (both are 76). Instead, substantially recycled (or reused or cycled) plastic materials (such as Plasmix "BA1") have a high H / C index and an average carbon index (around 80).

[0305] In this way it is possible to analyze the behavior of the pyrolysis material (or pyrolysis material) with respect to the two variables presented (H / C index and carbon index).

[0306] The PAT5 mixture is the average composition of the four above (PAT1, PAT2, PAT3 and PAT4) and was used to validate the model and experiments.

[0307] (Pyrolysis Apparatus Used in the Examples ("Apparatus 1")) In the present invention, the pyrolysis apparatus used in the examples is composed of the following: - a reactor (thermostatic or thermostatic) comprising: Flanges for filling (or loading) material; A dip tube for inserting inert gas (nitrogen), a port (N1) for connection to any extruder and for admitting a substantially plastic material; A port (N2) for discharging steam (or vapor); and Openings (NT1, NT2, NT3, NP) for thermocouples for measuring temperature and pressure, respectively; and Two openings (NL1, NL2) for measuring the level, - a stirring system (or steering system) for said reactor (or reactor), comprising an anchor stirrer (or anchor agitator) (low rotation speed (tip speed: about 0.1 m / s)) and a baffle, - a flow meter (or flow meter or flow velocity meter) equipped with a fine adjustment valve (or fine adjustment valve) for adjusting the rate of flow of the inerting gas into the reactor; - a pressure transducer located at the top (or upper or top) of the reactor and a local pressure gauge (or local pressure gauge) reading the pressure of the gas (or gas) inside the reactor; - 3 thermocouples for measuring the actual temperature, located in the lower part of the reactor; - a reactor temperature regulating system, which reads the temperature value of one of three thermocouples and acts by feedback on the thermoset system, so that its control parameters are properly calibrated to ensure high thermal stability (temperature fluctuation: less than 5°C); - a level indicator, by using a differential pressure sensor, which reads the hydrostatic head of the reactor (the pressure difference between the top and bottom of the reactor); - a condenser (or cooler or condenser) for condensing (or cooling) the steam (or vapor) released from the reactor, which is kept at -10°C by a cooling fluid (or cooling fluid), which flows (or is made to flow) from a cooling unit at a controlled (or managed or controlled) temperature; a valve for regulating the flow of the gas discharged from the reactor, the valve being located between the reactor and the condenser; - A reactor pressure regulating system, which reads the pressure value of a pressure transducer and acts on a regulating valve by feedback, thereby ensuring high pressure stability (pressure fluctuation: less than 50 mbar); - an expansion flask (or an expandable flask), which is sealed and connected to the upper outlet (or upper outlet) of the concentrator and is intended to recover the fraction (or fractions) of the gas (or gases) that is not concentrated, a receiving vessel (or receptacle or container or receiver) sealed and connected to the lower outlet of the concentrator and intended for collecting the concentrated fraction (and therefore for collecting it in liquid form), the vent of which is connected to the upper outlet of the concentrator, - a valve for intercepting incoming nitrogen; a valve for intercepting the liquid product discharged from the concentrator and then sealing the connection with a receiving vessel; a valve for intercepting the gas product released from the condenser and then sealing the connection with the expansion flask; - a twin screw extruder (or twin screw extruder) for dosing the granulated polymer mixture into a reactor through a port for receiving a substantially plastic material; a gravimetric doser (or gravimetric injector) for dosing the granulated polymer mixture into the hopper of a twin-screw extruder (the twin-screw extruder for dosing the granulated polymer mixture into a reactor).

[0308] The locations (or places or positions) of the ports for introducing substantially plastic material, the ports for discharging steam (or vapor), and the ports for discharging solid material are D1 <H / 3、D2<H / 3、DJ> D1, DJ>H / 3, DS>D1, D3=0 (there is a drain at the bottom) (see the definition above). The reactor has a substantially convex, substantially axisymmetric profile (as defined above). The lower end is hemispherical and the upper end is flat.

[0309] (Example of preparing a granulated polymer mixture) Formulations (or compounds) (PAT1, PAT2, PAT3, PAT4, PAT5) were prepared as described in the composition table provided above. For example, a mixture "PAT1" was prepared, which contained the following materials: 42 parts low density polyethylene (LDPE) type Riblene® FC20 (manufacturer: Versalis) 24 parts linear low density polyethylene (LLDPE) type Flexirene® CL10 (manufacturer: Versalis) 4-part high density polyethylene (HDPE) type Eraclene® BC82 (manufacturer: Versalis) 30 parts polypropylene (PP) type ISPLEN® PP040 (manufacturer: Repsol)

[0310] In a Coperion ZSK 26 twin screw extruder, the compound prepared as described above was melted at 250°C and mixed using the mixing elements present in the extruder screws and passed through a die. The total residence time in the extruder was less than 1 minute. The polymer mixture obtained above was then cooled in a liquid bath and granulated into granules, the diameter and length of which were approximately 3 mm. In this way, mixtures of pelletized polymers (PAT1, PAT2, PAT3, PAT4 and PAT5) were prepared.

[0311] (Pyrolysis Examples 1 to 8 (Comparative Examples and Examples of the Invention)) Examples 1-8 were prepared using the granulated polymer mixes, set-ups, temperature profiles, and pressures set forth in the table below (set-ups and thermal profiles are described in more detail below).

[0312] [Table 6]

[0313] In the reactor of "Apparatus 1" above, the granulated polymer mixture was introduced (or charged) at room temperature until it reached 1 / 3 of the geometric volume of the reactor. The port through which the molten polymer could enter from the extruder was unused and plugged (or plugged).

[0314] The valve for regulating the flow of gas released from the reactor was manually set to fully open.

[0315] Next, nitrogen was injected from below through the dip tube and the fine adjustment valve of the flow meter was fully opened.

[0316] The gas contained in the reactor was then removed for a certain period of time (=24 hours) to ensure the exclusion of oxygen.

[0317] The valves on the gas and liquid product outlets from the condenser were then closed. Immediately thereafter the nitrogen supply was discontinued. It was then connected to an expansion flask for collecting the produced gas and to a receiving vessel for collecting the produced liquid.

[0318] The valves on the gas and liquid product outlets from the condenser were then reopened.

[0319] The valve for regulating the flow of gas out of the reactor was set to automatically adjust to a value selected for the test (in this example, 0 barg = 1 bar(a) (absolute)).

[0320] Nitrogen was then injected from below through the dip tube, but the flow rate was selected to be low so that the amount of nitrogen collected in the inflatable balloon did not exceed 30% of the maximum capacity of the balloon before its replacement.

[0321] The modalities (or formats) described above for Examples 1 to 8 are hereinafter referred to (or defined) as "Set-up A1 (or Setup A1)."

[0322] Turn on the reactor's thermal regulation system and set the following program: 1 First heating ramp (or heating ramp): 4 °C / min (until 380 °C is reached) 2 Keep warm (or maintain temperature): 380℃, 3 hours 3 Second heating ramp (or heating ramp): 2 °C / min (until 430 °C is reached) 4 Keep warm (or maintain temperature): 430℃, 3 hours 5 Third heating ramp (or heating ramp): 2 °C / min (until 480 °C is reached) 6 Heat retention (or temperature maintenance): 480℃, 3 hours 7 Stopping (or switching off) the heat

[0323] The above-described temperature vs. time profile will hereinafter be referred to as "Profile T1."

[0324] (cleaning) 12 hours after the end of the program, it was checked that the reactor temperature was below 60° C., the nitrogen supply was interrupted, the valves were closed to stop the liquid and gas products from being discharged from the condenser, and the reactor flanges were opened.

[0325] The inside of the reactor was carefully cleaned, with the aim of removing any deposits and dust that may have formed in the reactor in contact with the liquids and gases produced.

[0326] (analysis) The bottom of the reactor was then completely cleared of all solid material, the solid material was weighed, and the vessel and expansion flask for receiving liquid were removed.

[0327] The liquid contained in the vessel (or container) for receiving (or housing) the liquid was weighed and then subjected to ultracentrifugation (Sorvall Evolution RC, model of Thermo Scientific ultracentrifuge) (25000RPM, 45 minutes).

[0328] Next, the fraction left at the bottom after ultracentrifugation (hereinafter referred to as the wax fraction) and the supernatant (hereinafter referred to as the oil fraction) were separated and weighed.

[0329] The oil percentage was calculated by dividing the weight of the resulting oil fraction by the weight of the material initially fed to the reactor.

[0330] The wax percentage was calculated by dividing the weight of the resulting wax fraction by the weight of the material initially fed to the reactor.

[0331] The carbon residue (char) percentage was calculated by dividing the weight of the resulting solid fraction by the weight of the material originally fed to the reactor.

[0332] The mass of gas produced was calculated as the difference between the weight of the material initially fed to the reactor and the sum of the weights of the wax fraction, the carbon residue (char) fraction and the oil fraction. The gas fraction produced was calculated by dividing the mass of the gas fraction calculated in this way by the weight of the material initially fed to the reactor.

[0333] The resulting fractions were analyzed using the techniques described above. Approximately 130 chemical compounds were identified.

[0334] For each of these chemical compounds, the atomic masses of each atom were used to calculate the number of atoms of each element and the atomic mass fraction of the atoms.

[0335] "C5-C12 yield" means the sum of the masses of chemical compounds having from 5 to 12 carbon atoms (inclusive) contained in the evaporated pyrolysis products based on the total mass of the pyrolysis products. Similarly, "C21 + "Yield" means the sum of the masses of chemical compounds having at least 21 carbon atoms contained in the evaporated pyrolysis products based on the total mass fed.

[0336] "C5-C12 fraction" means the sum of the masses of chemical compounds having from 5 to 12 carbon atoms (inclusive) contained in a product, based on the total mass of the product. Similarly, "C21+ fraction" means the sum of the masses of chemical compounds having at least 21 carbon atoms contained in a product, based on the total mass of the product.

[0337] Thus, evaporated pyrolysis products refers to the sum of the gas fraction, the oil fraction and the wax fraction (not including the remaining solids (char)).

[0338] For such purposes, a gas chromatographic analysis is carried out for each of the gas, oil and wax fractions, respectively. The "C" yield of a given compound is then calculated as follows:

[0339]

number

[0340] In the formula, x C, <frac>< / frac>And f OIL and f WAX is as follows: -x C, <frac>< / frac> is the indicated fraction of product <frac>is the mass fraction (or mass fraction) of compound C contained in ( <frac>Examples include GAS = gas fraction, OIL = oil fraction, or WAX = wax fraction. In the case of the GAS fraction, the nitrogen fraction present was previously excluded from the calculation (nitrogen is supplied as an inert gas and is not a pyrolysis product). The chromatograms of the GAS fractions show the parts by volume (or parts by volume) converted to parts by weight, which are assumed to be the corresponding (or equivalent) number of molar parts, which are then calculated to parts by weight since the molecular weights of the compounds are known. -f OIL and f WAX are the mass fractions of the oil and wax fractions, respectively, and are obtained by dividing the weight of collected material by the weight of material fed to pyrolysis. Meanwhile, the weight of the gas produced was calculated using the difference between the weight of the material fed to the pyrolysis and the sum of the weights of the oil fraction, the wax fraction and the solid residue (char) fraction.

[0341]

number

[0342] f GAS Instead, M GAS and M. FEED It is calculated from the ratio of

[0343] (Pyrolysis Examples 9-11) Examples 9, 10 and 11 were carried out under the same setup and thermal profile conditions as Examples 1 to 8 (setup A1 and temperature profile T1). The pressure was set at 3 bar(a) (absolute). Indeed, the aim was to assess the reproducibility (or repeatability) and therefore the reliability (or accuracy or reliability) of the results obtained. Often, in a design of experiments (DOE), it is decided to repeat the central point three times.

[0344] The mixture used in all three examples was PAT5, which has been previously reported and has a constant composition, i.e., the average composition (or composition or composition) of PAT1, PAT2, PAT3 and PAT4. In the same manner as in Examples 1 to 8, the mixture was extruded (or extrusion molded) to form (or granulate) a particulate (or granular) polymer.

[0345] (Pyrolysis Examples 12 to 13 (Comparative Examples and Examples of the Invention)) The examples according to the invention and the comparative examples (Examples 1 and 2) were repeated (with the polymer mixture PAT1, carried out at pyrolysis pressures of 1 and 5 bar(a) (absolute)), but with the different thermal profiles just described.

[0346] The following program was set in the thermal regulation system of the reactor: (1) Heat Ramp: 4°C / min (until 430°C is reached), (2) Keep warm (or maintain temperature): 430℃, 6 hours, (3) Stopping (or switching off) the heating

[0347] Thus, the difference with the above example is the reduction of the pyrolysis treatment duration from 9 to 6 hours (+ ramp time) and by choosing an intermediate stage temperature of 430°C as the treatment temperature.

[0348] The temperature profile (or temperature profile) thus altered (or corrected) is hereinafter referred to as "Profile T2". Two different temperature profiles (T1 and T2) are shown in the graph of FIG.

[0349] In examples 12 and 13, a polymer mixture of PAT1 was processed. The pressure set was atmospheric in example 12 and 5 bar(a) (absolute) in example 13.

[0350] (Pyrolysis Examples 14 to 17 (Examples of the Invention)) Examples 14 to 17 refer to pyrolysis plants (or pyrolysis factories) operated in semi-continuous mode and according to the "A2" set-up (or configuration), which is described in more detail below.

[0351] The port of “Apparatus 1” was opened and connected to the twin screw extruder. This port is the port (or entry port) through which the polymer can enter from the extruder (or extruder). The substantially plastic material was not initially loaded into a reactor as was done in Examples 1-13 described above, but was instead loaded into a hopper of a gravimetric unit for feeding into an extruder. The extruder screw speed was adjusted to ensure that the extruder hopper remained empty (a "hungry mouse"). The flow rate of the gravimetric doser was adjusted to bring the reactor level to equal 40% of the total volume of the reactor while maintaining the temperature at 430°C. The volumetric flow rate of the polymer leaving the extruder was calculated by dividing the mass flow rate set at the dispenser by the density of the molten polymer. Before starting the feed of the substantially plastic material, the pyrolysis reactor atmosphere was inerted (as was done in the example above) by admitting nitrogen as an inert gas. The valves for regulating the flow of gases discharged from the reactor were set to automatic regulation at the valves selected for testing (as already done in the example above). The reaction and preparation were allowed to stabilize for a period of 6 hours, during which the nitrogen inlet was closed. Once the stabilization time was over, the residence time was measured. It was calculated by dividing the flow rate by the density of the substantially plastic material fed in the molten state and the volume used in the reactor (40% of the total (as above)). The residence time was equal to about 6.3 hours. Unlike the batch examples, it is not possible to estimate the mass of solid residue until the end of the test, since the examples are carried out consecutively without opening the reactor from one example to the next. Therefore, the mass of uncondensed vapor was estimated based on the capacity (or volume) of the inflatable balloon and the density of the gas (or vapor) calculated based on a compositional analysis of the gas (or vapor) present therein. The mass of solids remaining in the reactor was then calculated as the difference between the mass of the substantially plastic material fed and the sum of the mass of the pyrolysis oil recovered and the mass of the gas thus estimated.

[0352]

number

[0353] Example 14 was carried out using the "PAT2" mixture as the substantially plastic material (after a first hour of stabilization with the same mixture, for an additional 2 hours at the pressures shown in the table). The products of pyrolysis were collected (as in the previous examples).

[0354] Immediately thereafter, without interrupting the pyrolysis, the material present in the hopper of the heavy doser was replaced with substantially recycled plastic material (e.g. Plasmix "BA1") and the pressure set point of the pyrolysis was adjusted (as shown in the table). The material in the reactor was allowed to change for 6 hours, and then a representative sample for testing (Example 17) was taken after 2 hours.

[0355] The pyrolysis pressure set point was then changed to atmospheric pressure (as shown in the table). Six hours was then allowed and a representative sample for testing (Example 18) was taken after 2 hours.

[0356] The pyrolysis pressure set point was then changed to atmospheric pressure (see table). Six hours was then allowed and then a representative sample (Example 19) was taken for testing after 2 hours.

[0357] The feed of substantially plastic material was discontinued until no further formation of concentrate was observed, while the temperature in the reactor was maintained constant in order to complete the pyrolysis of what was in the reactor. The reactor was then left to cool, the nitrogen flow was re-started, and finally the pressure was reduced and the reactor was opened. No fouling was observed.

[0358] Finally, the process of pyrolysis was observed to be regular (or normal or normal). Changes in the substantially plastic material fed (as occurs between Tests 16 and 17) and changes in the pyrolysis pressure settings (as occurs in Tests 16, 17, and 18) did not cause the automatic adjustment to become unstable. The concentrated product did not show the presence of any polymer or solid residue that would have been present in the event of foaming and the resulting entrainment.

[0359] (result) The table below shows the achieved C5-C12 yield, C21+ yield and overall quality of the product ("+" means C5-12 yield ≥ 30% and C21+ yield ≤ 3% at the same time). (As a function of H / C index (or H / C index or H / C idx), carbon index (or carbon index or carbon index or CI), total index (the total index is expressed as H / C index of the product x carbon index / 10000)

[0360] [Table 7]

[0361] [Table 8]

[0362] [Table 9]

[0363] (Discussion of Results) One of the objectives of the present invention is to overcome the criticality associated with the pyrolysis of substantially plastic materials, where the composition is highly variable (and therefore substantially inconstant), while maintaining high quality of the products of pyrolysis.

[0364] Therefore, mixtures PAT1, PAT2, PAT3 and PAT4 were selected to evaluate the most suitable pyrolysis conditions, where the incoming raw material undergoes significant changes. - PAT1: exclusively made from vinyl polymers (polythene and polypropylene) - PAT2: Contains a large amount of cellulose (20.2%) - PAT3: Contains a large amount of polystyrene (27%) - PAT4: Contains a large amount (26.5%) of polyethylene terephthalate (PET).

[0365] Experiments performed have shown that for every composition of incoming feedstock, there are no optimal process conditions for the purposes of the present invention.

[0366] In particular, when the H / C index is large and the carbon index is large, it is quite clear that it is very advantageous to carry out pyrolysis at pressures higher than atmospheric pressure. In Example 2 (carried out at 5 bar(a) (absolute)) the yield of C5-C12 is almost doubled compared to Example 1 (comparative) (carried out at atmospheric pressure), and the share of the yield of the undesired fraction C21 and above, C21+, is drastically reduced from 3.7% to 0.24%.

[0367] Comparative Example 3 and Inventive Example 4 show the effect of pressure, where the feed H / C index is similar to Examples 1 and 2, but with a reduced carbon index (86 to 76). Also, in this case, there is a significant advantage in carrying out pyrolysis at high pressure, even if the advantage is reduced (the yield of C5-C12 goes from 34% to 49%, while the yield of undesirable C21+ goes from 22.3% to 2.1%).

[0368] Comparative Example 5 and Inventive Example 6 show the effect of pressure, where the carbon index of the feedstock used is essentially the same as in Examples 1 and 2 (86 in both cases), but the H / C index is significantly reduced (from 100 to 83). Also, in this case, there is a significant advantage in operating pyrolysis at high pressures, even if the advantage is reduced (C5-C12 yield goes from 47% to 58%, while the undesirable C21+ yield goes from 3.8% to 0.7%).

[0369] Comparative Example 7 and Inventive Example 8 show the effect of pressure, where the carbon index of the material used is substantially the same as the low value used in Examples 3 and 4 (77, very close to the value (76) in Examples 3 and 4), and the H / C index is substantially the same as the low value used in Examples 5 and 6 (83 in both cases). Surprisingly, in this case, there was no benefit in increasing the pyrolysis pressure: the C5-C12 yield remained essentially constant (although it decreased from 33% to 32%). However, it is very important to note that the yield of C21+ increases dramatically, from 2.9% to over 10%.

[0370] This therefore provides evidence that for some feed mixes it is advantageous to operate at high pressure, but for other feed mixes there is no advantage to operating at high pressure.

[0371] Moreover, even in the case of the preferred objective of obtaining a C5-C12 yield of at least 30%, and even more preferably at least 40%, and at the same time a C21 or higher yield (C21+) of at most 3%, it is clear that even under the same conditions (PAT1, PAT2, PAT3), this objective can only be achieved by using a high pressure system, whereas for the others (PAR4) it is more advantageous to keep the system at a lower pressure.

[0372] It should be noted that because such evidence is the applicant's first discovery, there is an opportunity to adjust the conditions of the process depending on the composition of the substantially plastic material being fed. As mentioned above, since this composition can vary during the process (especially when carried out in semi-continuous or continuous mode), the process according to the invention advantageously allows for adjustment of the pressure during the pyrolysis stages, thus maximizing results when the feedstock input to the pyrolysis is varied. Preferably, the process according to the present invention also allows the achievement of the preferred objective of obtaining a C5-C12 yield of at least 30%, more preferably at least 40%, and at the same time a maximum C21 or higher yield (C21+) of 3%, by appropriately adjusting the pyrolysis pressure depending on the composition of the supplied plastic material.

[0373] It should be noted that the use of such a criterion, compared with the more preferred modes (of carrying out the pyrolysis process at a pressure at least equal to the threshold pressure (PS) (where the total index (= carbon index (or CI index) x H / C index ÷ 10000) is ≧0.7) and at a pressure lower than the threshold pressure (PS) (where the total index = less than 0.7), makes it possible to obtain a production of a product that maximizes the C5-C12 yield and at the same time minimizes the C21+ yield, in particular for values ​​of the threshold pressure (PS) between 2.0 and 2.9 bar(a) (absolute).

[0374] In fact, in Examples 1 to 11 of the patent, by applying this criterion, a yield (or yield or amount) of C5 to C12 of at least 30% was obtained, and at the same time, a yield (or yield or amount) of C21 or more (C21+) of up to 3% was obtained. Furthermore, in the resulting pyrolysis oil, the C21+ fraction is less than or equal to 3.5%, while the C5-C12 fraction is at least 35% in the pyrolysis oil.

[0375] It has been demonstrated that the process (or step, or treatment, or manufacturing method, or method) according to the present invention has high reproducibility (or repeatability), as shown in Examples 9 to 11.

[0376] Additionally, Examples 12 and 13 show similar results consistent with the teachings of the present invention that can be obtained by using various thermal profiles.

[0377] Surprisingly, the process according to the invention allows the pyrolysis of substantially plastic materials containing very large amounts of polymers / materials. The carbon content is low, the carbon index may be less than 80, and the oxygen content is high. In particular, in the substantially plastic material, the cellulose content is greater than 20%. No operational or fouling problems are encountered, and the yield of C5-C21 is high, the yield of C21 is reduced, and the yield is even higher (both in batch mode (example 4) and in semi-continuous mode (example 14)).

[0378] Examples 15, 16 and 17 also show that the present invention is highly effective even with substantially plastic materials that are the remainder (or residue or remainder or residue) of Plasmix type separation (or sorting). In fact, when the pressure is increased, the OI index is greater than 0.7 and the yield of the C5-C12 fraction increases significantly. Furthermore, increasing the pressure also significantly reduces the yield of undesirable C21+.

[0379] Examples 14, 15, 16 and 17 also show that the semi-continuous process allows for handling both fluctuations in the composition of the substantially plastic material being fed and fluctuations in pressure without causing fouling or changes in the process (such as resulting in entrainment of polymer and / or solid residues (e.g., fouling)).

[0380] As can be seen from the comparison between the examples and the comparative examples, pyrolysis carried out at 5 bar(a) (absolute) resulted in a significant increase in the tetrahydrofuran (THF) content in the liquid hydrocarbon(s) produced (from 175% to 250%) when compared to the same test carried out at ambient pressure, where the substantially plastic material is characterized by an "Overall Index" (OI) of 0.7 or greater.

[0381] Similarly, tests starting with a substantially plastic material having an overall index greater than 0.7 reduced the benzoic acid content. In the case of Example 2, no benzoic acid was observed (100% reduction) when compared to Example 1 (PAT1 mixture). Also, an important reduction was obtained in Example 4 compared to Example 3 (PAT2 was used as the mixture in the test), where the reduction was more than 80%. In the case of Example 6, the decrease (or reduction) was similar to that of Example 5 (PAT3 mixture), but more pronounced (-23%).

[0382] In the same example, it can be seen that the amount of isobutene is also significantly reduced compared to the respective comparative examples, and therefore the quality of the resulting naphtha is also improved.

[0383] It should also be noted that the best results are obtained by the process according to the invention, where the content of polyolefins in the plastic material is low, i.e., such material is normally discarded by a sorting process for recovery of homoplastic materials.< / frac> < / frac>

Claims

1. 1. A process for pyrolyzing a substantially plastic material to obtain at least liquid hydrocarbons, said hydrocarbons being in a liquid state at 25° C., the process comprising the following steps (a) to (e): (a) feeding the substantially plastic material, optionally already in a molten state and / or preheated state, into a reactor for pyrolysis; (b) subjecting the material in the pyrolysis reactor to a temperature of between 330°C and 580°C and a pressure of between atmospheric and 13 bar(a) in the substantial absence of oxygen; (c) maintaining the material in the pyrolysis reactor at a temperature of from 330°C to 580°C for a time sufficient to produce at least one gaseous effluent in the pyrolysis reactor; (d) adjusting the pressure in the pyrolysis reactor in relation to characteristic parameters defined by the composition of the substantially plastic material and / or characteristic parameters defined by the products of the pyrolysis process, while maintaining said pressure at a value between atmospheric pressure and 13 bar(a); (e) a step of partially or totally condensing the gaseous effluent to form at least one fluid containing liquid hydrocarbons, the hydrocarbons being in a liquid state at 25° C., the fluid being quantitatively at least 10% by weight based on the weight of the substantially plastic material fed; The process includes:

2. 2. The process for pyrolyzing a substantially plastic material according to claim 1, wherein the characteristic parameter defined by the product of the pyrolysis process is the yield of production of said product and / or a characteristic measured on said product.

3. 10. The process for pyrolyzing a substantially plastic material of claim 1, wherein the provided substantially plastic material has a non-constant composition.

4. 1. An apparatus specifically designed for the pyrolysis of substantially plastic materials, to obtain at least liquid hydrocarbons, said hydrocarbons being in a liquid state at 25°C, as claimed in any one of claims 1 to 3, said apparatus comprising: at least one reactor for pyrolyzing the substantially plastic material; at least one condensation separator for vapors produced in the reactor; and at least one system for adjusting the pressure in the reactor in relation to one or more characteristic parameters of the substantially plastic material fed and / or one or more characteristic parameters of the pyrolysis oil produced by the reactor.

1. An apparatus comprising:

5. 1. An apparatus for pyrolyzing a substantially plastic material, to obtain at least hydrocarbons, as claimed in claim 4, wherein the hydrocarbons are in a liquid state at 25° C., and the system comprises the following process: - adjusting the heat extracted from the enrichment separator located downstream of the reactor and in fluid connection with the reactor, preferably by adjusting the power of the enrichment separator; If providing an auxiliary gaseous fluid, adjusting the flow rate of said auxiliary gaseous fluid; controlling the pressure regulation of the pyrolysis vapor by adjusting the opening of a valve, through which the pyrolysis vapor passes before entering at least one condensation separator; controlling the pressure regulation of the remaining gas by adjusting the opening of a valve, wherein the remaining gas comprises the hydrocarbon-containing fluid that has not been enriched after passing through at least one enrichment separator, and passing the remaining gas through the valve; Double pressure regulation is performed by combining a control mode for regulating the pressure of the pyrolysis vapor and a control mode for regulating the pressure of the remaining gas. and regulating the pressure in the operation of the reactor according to one or more of the following:

6. 10. An apparatus for pyrolyzing a substantially plastic material, the apparatus being for obtaining at least liquid hydrocarbons, the hydrocarbons being in a liquid state at 25°C, as claimed in claim 5, the apparatus further comprising at least one valve for regulating the pressure of unenriched vapor, the valve being located downstream of the enrichment separator, the pressure regulation system of the reactor being in split range mode and also acting on the valve regulating the pressure of the unenriched vapor.

7. A reactor specifically designed for the pyrolysis of substantially plastic materials, for obtaining at least liquid hydrocarbons, wherein the hydrocarbons are in a liquid state at 25°C, as claimed in any one of claims 1 to 3, the reactor comprising: (i) a reactor for pyrolyzing a substantially plastic material; (i) at least one port (N2) for discharging a gaseous product, the port (N2) being located at the top of the reactor or at a distance from the top of the reactor, the distance being less than or equal to one-third of the height (H) of the reactor; (ii) At least one port (N3) for removing solid products, which is located at the bottom of the reactor or at a distance from the bottom of the reactor, said distance being less than or equal to one-third of the height (H) of the reactor; (iii) at least one port (N1) for admitting a substantially plastic material, the port (N1) being at a distance (D1) from the top of the reactor, the distance (D1) being equal to or greater than the distance (D2) between the port from which the gaseous product leaves and the top of the reactor; (iv) at least one stirrer (12); (v) at least one jacket for heating the reactor, the height (DJ) corresponding to the distance from the top of the reactor to the highest point of the body of the reactor heated by the jacket being equal to or greater than the distance (D1) between the port for introducing the substantially plastic material and the top of the reactor; (vi) at least one opening for inserting a temperature transducer; (vii) at least one opening for inserting a pressure transducer; (viii) at least one opening for inserting a sensor for measuring the level of the reactor; Including, A reactor characterized in that there is a separator (demister) for carrying over material located below and / or at the port for exiting said gaseous product.

8. 10. A reactor for pyrolysis of a substantially plastic material, for obtaining at least liquid hydrocarbons, wherein the hydrocarbons are in a liquid state at 25° C., as claimed in claim 7, and wherein the stirrer (12) comprises a stirring element positioned at a distance (DS) from the top of the reactor, the distance (DS) being equal to or greater than the distance (D1) between the port for introducing the substantially plastic material and the top of the reactor.

9. 4. A mixture obtainable by the process of any one of claims 1 to 3, comprising hydrocarbons and tetrahydrofuran, the amount of said hydrocarbons being more than 90% by weight, based on the total weight of the mixture, the amount of said tetrahydrofuran being 0.01% to 0.25% by weight, even more preferably 0.07% to 0.19% by weight, based on the total weight of the mixture; preferably comprising benzoic acid, the content of which is 2% by weight or less, even more preferably 0.01% to 1% by weight, based on the total weight of the mixture; and / or preferably comprising isobutene, the content of which is 0.55% by weight or less, even more preferably 0.15% to 0.3% by weight, based on the total weight of the mixture.

10. 10. Use of the mixture according to claim 9 for feeding a cracking plant.

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