Compositions and methods of use of fine mineral matter as catalysts for chemical recycling - Patents.com

Abstract

The disclosed embodiments relate to the use of coal-derived fine mineral matter in the chemical recycling of plastics or solid plastic waste. The mineral-based catalysts disclosed herein benefit catalytic cracking, gasification, and steam reforming processes to maximize carbon utilization and the production of original-quality plastics from recycled or renewable feedstocks while reducing plastic pollution in the environment. The catalysts can be based on inorganic fine mineral matter, a natural, ancient mineral mixture found in coal deposits, and contain multiple transition metals, such as iron, copper, and manganese, as well as calcium, barium, magnesium, potassium, and sodium, which can act as promoters. The addition of the catalysts can convert plastics into synthesis gas at the energy rate of conventional technologies.

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This disclosure claims priority to U.S. Provisional Patent Application No. 62 / 927,493, filed October 29, 2019, entitled "Coal-derived fine mineral matter as a catalyst for the chemical recycling of plastics, mixed plastic solid waste, and heavy oil feedstocks," which is incorporated herein by reference in its entirety.

[0002] Field Various embodiments of the present disclosure generally relate to the use of fine mineral matter, such as coal-derived fine mineral matter, in the chemical recycling of plastic and / or solid mixed plastic waste, and more specifically, to the recycling of waste and heavy oil feedstocks in the presence of mineral-based catalysts that enhance the efficiency of recycling during catalytic cracking, gasification, and steam reforming processes. [Background technology]

[0003] The synthetic plastics industry has been one of the great industrial successes of the past 50 years. For example, plastic production soared from 15 million metric tons in 1964 to 311 million tons in 2014 and is expected to double again over the next 20 years, with new uses and applications for plastics being realized each year. Along with the widespread use of plastics in the marketplace, an unintended consequence of this widespread use is a proportional and rapid increase in plastic waste and litter. It is estimated that the amount of plastic that ends up in landfills worldwide is nearly half of annual production—over 150 million tons per year. Disposal of this waste is problematic due to the cost and availability of landfills, the toxicity of incineration, and the limited number of cycles that mechanical recycling can support.

[0004] Conventional recycling processes have several drawbacks that prevent their scalability and widespread use in response to the increasing prevalence of plastic use in industry. Current recycling processes lack the capacity to process a variety of plastic wastes, leaving the remaining waste to be landfilled. For wastes that can be recycled and processed, the products made from them are generally of lower quality than the original compounds, resulting in less desirable products and shorter life cycles. For example, this makes them more likely to end up in landfills. Summary of the Invention [Means for solving the problem]

[0005] According to one embodiment of the present invention, a chemical recycling process includes obtaining a quantity of catalytic mineral fines derived from coal and / or mined from natural sources including volcanic basalt, glacial debris deposits, potassium iron silicate, and / or coastal sediments, and having a particle size ranging from less than about 50 μm to about 2 μm, and contacting a molten polymer or its vapor with the catalytic mineral fines at cracking or gasification temperatures in the presence of oxygen and / or water vapor to form a synthesis gas product.

[0006] The synthesis gas product may include one or more of H2, CO, CH4, CO2, HO, and inert gases. The catalytic fine mineral matter includes at least one transition metal selected from the group consisting of Fe, Cu, Mn, Mo, Zn, Co, or combinations thereof, in the following concentrations: Fe 14,000-45,000 ppm, Cu 10-50 ppm, Mn 100-700 ppm, Mo 1-2 ppm, Zn 20-120 ppm, and Co 10-15 ppm, where ppm is measured using ICP-AES techniques in a heated digester utilizing nitric acid, hydrochloric acid, and hydrogen peroxide. In some embodiments, the catalytic fine mineral contains alkali and alkaline earth metals Ca, K, Na, Mg, or a combination thereof at the following concentrations: Ca 1,000-18,000 ppm, K 600-4,000 ppm, Na 300-1,500 ppm, and Mg 20-8,000 ppm. The catalytic fine mineral can be used as either a support material or a catalyst. The concentration of the catalytic fine mineral can range from 0.5 to 8% by volume, or a catalyst / feedstock ratio of about 1:5 to about 1:100 by weight. In some embodiments, the particle size can range from approximately 5 micrometers to approximately 0.5 micrometers.

[0007] In particular, the molten polymer in the methods disclosed herein can be produced following catalytic processing of post-industrial or post-consumer plastic waste, solid mixed plastic waste, or petrochemical heavy oils and alkanes by steam cracking, gasification, and reforming processes. Liquefaction precedes gasification, and is accomplished via pyrolysis, thermal cracking, or steam cracking to convert the plastic waste to synthetic heavy oils and condensable gases, which are injected into a gasifier and / or steam reformer. The methods can also include scrubbing and / or hydrogenation following gasification to improve the composition of the synthesis gas product. In some embodiments, the methods can subject the synthesis gas to one or more of the KDV process, the Texaco process, or processes utilizing single-column or double-column fluidized bed, fixed bed, and entrained flow reactors.

[0008] In some embodiments, the steam cracking may include hydrothermal decomposition in supercritical water. The reforming process may include catalytic steam reforming of methane to a synthesis gas product. The synthesis gas product may be used as a heat source to promote steam cracking or gasification, or as a gas source to support hydrocracking. Heating may be carried out at a temperature ranging from about 200 degrees Celsius to about 500 degrees Celsius. In some embodiments, the method may further include passing electricity through the synthesis gas product. Catalytic steam cracking may be batch or continuous flow (slurry type).

[0009] This disclosure will be more fully understood from the following detailed description taken in conjunction with the accompanying drawings, in which: [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 shows a flow diagram illustrating a method for recycling hydrocarbon plastics according to an embodiment disclosed herein. [Figure 2] FIG. 2 shows a graph of the degradation of stabilized linear low density polyethylene (LLDPE) in air according to one embodiment of the presently disclosed embodiments. [Figure 3] FIG. 3 shows a graph of the degradation of modified LLDPE in air according to one embodiment of the presently disclosed embodiments. [Figure 4] FIG. 4 shows a graph of the weight change of the base LLDPE at various rates according to one embodiment of the presently disclosed embodiments. [Figure 5] FIG. 5 shows a graph of weight change of modified LLDPE at various rates according to one embodiment of the presently disclosed embodiments. DETAILED DESCRIPTION OF THE INVENTION

[0011] Detailed Description Certain exemplary embodiments are described herein to provide a general understanding of the principles of the structure, function, manufacture, and use of the systems, devices, and methods disclosed herein. One or more examples of these embodiments are illustrated in the accompanying drawings. Those skilled in the art will understand that the systems, devices, and methods specifically described herein and shown in the accompanying drawings are non-limiting exemplary embodiments, and that the scope of the disclosure is defined only by the claims. Features shown or described in connection with one exemplary embodiment may be combined with features of other embodiments. Such modifications and variations are intended to be included within the scope of the present disclosure. Furthermore, those skilled in the art will recognize that the ranges disclosed herein are approximate and merely exemplary. The concentration ranges of the transition metal, promoter, and other compounds that make up the catalyst may vary within acceptable values.

[0012] In exemplary embodiments, coal-derived fine mineral matter is utilized in the chemical recycling of plastics or solid plastic waste. The fine mineral matter can serve to lower the activation energy for pyrolysis of polyethylene (PE) feedstock in the presence of minerals within the scope of the presently disclosed embodiments in catalytic cracking, gasification, and steam reforming processes. Such technology can support the mission of reducing plastic pollution in the environment while maximizing carbon utilization and the production of original-quality plastics from recycled or renewable feedstocks. For example, the compositions and methods disclosed herein can be used to process any type of plastic waste (PW), whether sorted or unsorted, and produce the same quality plastics. Such technology can enable the conversion of waste plastics into raw materials for new plastics, rather than burning them for energy recovery or landfilling. In some embodiments, the fine mineral matter of the presently disclosed embodiments can be utilized as a support material for processes discussed in more detail below.

[0013] In an exemplary embodiment, chemical recycling can be used to provide unlimited recycling of any plastic material (mixed or sorted), where the focus is on recovering the building blocks of the plastic material. Chemical recycling has great potential for heterogeneous and contaminated plastic waste materials when separation is not economically or technically feasible. Chemical recycling can be used in closed-loop recycling, where polymers are converted into smaller molecules that are then repurposed into the same products from which they were originally recovered, or in open-loop recycling, where those smaller molecules are repurposed into different products. Chemical recycling has the effect of reducing plastic pollution in the environment while transferring the value of the original material to next-generation products, reducing the consumption of fossil raw materials (carbon storage), and reducing GHG emissions associated with fossil raw materials.

[0014] Chemical recycling routes can be broadly divided into thermochemical and catalytic conversion, including steam cracking, pyrolysis, gasification, fluid catalytic cracking, and hydrocracking, among others. Cracking, gasification, and steam reforming processes can be appropriately catalyzed and carried out in the presence of air, oxygen, or steam. These techniques are particularly interesting for polyolefins, polymers that are highly susceptible to oxidative pyrolysis and account for over 60% of plastic waste generated. Many other types of polymers may also be highly susceptible to catalytic oxidative cracking, gasification, and reforming, especially in the presence of steam or supercritical water. Some non-limiting examples of polymers to which the compositions and methods disclosed herein can be applied include acrylics, styrenes, vinyls, polyesters, polyethers, polycarbonates, polyurethanes, polyamides, polyimides, cellulosic plastics, and combinations and copolymers of the above.

[0015] Those skilled in the art will recognize that conventional technology for the production of monomers, mostly olefins, is based on the direct thermal cracking of naphtha / alkanes. During cracking, a portion of the feedstock is converted to by-products that are not useful in the direct synthesis of plastics: 40-60% are hydrocarbons other than olefins, 4-25% are methane, and up to 10% are benzene. Steam is typically used to reduce the partial pressure of the hydrocarbons. In the presence of oxygen-containing molecules in the cracker, carbon oxides (CO, CO2) and hydrogen can also be produced via steam reforming and gasification.

[0016] If the feedstock is mixed plastic waste, more methane is expected to be produced. To achieve 100% carbon capture, further processes can be carried out, such as steam reforming of hydrocarbons to CO and H2, and combustion of the feedstock to cover part of the heat demand and capture carbon in the form of CO2 (which also balances the H2 / CO ratio of the syngas). For the combustion process, O2 can be produced via the electrolysis of water (oxygen combustion). The combustion, electrolysis and steam reforming routes are much less fuel-dependent than direct steam cracking of the feedstock to monomers.

[0017] In some embodiments, catalytic thermal cracking of plastic waste can be carried out in a fluidized bed reactor. For example, in catalytic thermal cracking, the catalyst and absorbent can be introduced in the form of bed material. In some embodiments, a double fluidized bed (DFB) can be used to separate the heat generation section (combustion) from the cracking section. Compared to a single fluidized bed reactor, the DFB configuration offers the additional advantage of diluting the cracking product with steam only (and not flue gas) and regenerating the catalyst from carbon deposits in a separate combustion section. The introduction of catalyst bed material into the fluidized bed reactor can be carried out during the pyrolysis stage or in a secondary stage of steam reforming of the pyrolysis product.

[0018] Steam cracking, as described above, produces a liquefied feedstock, a portion of which can then be sent to a gasification reactor to produce synthesis gas, a combination of hydrogen and carbon monoxide. Hydrogenation can also be used to remove sulfur impurities at the end of the gasification process. The synthesis gas produced by gasification can be used in the production of petroleum-like products via Fischer-Tropsch synthesis (FTS) or via methanol and DME synthesis, followed by methanol-to-gasoline (MTG) or methanol-to-olefins (MTO) conversion, as discussed in detail below. Methanol is one of the world's most produced chemicals because it is used as a reactant to produce several commodity chemicals, such as formaldehyde, acetic acid, and methylamine. Synthesis gas can also be used as a heat source to power steam cracking or as a gas source to support hydrocracking.

[0019] The use of catalytic steam cracking can lead to liquid products with lighter compositions and reduce coke formation due to the selective low-temperature steam reforming (LTSR) of polycyclic aromatic hydrocarbons (coke precursors). The additional hydrogen formed in situ as a result of both LTSR and water-gas reaction can also participate in upgrading due to the saturation of hydrocarbon radicals formed in catalytic steam cracking. To increase the efficiency and effectiveness of catalytic steam cracking, active and selective catalysts that are stable in heavy oil feedstocks and aqueous environments can be used, as described in more detail below. Catalytic steam cracking can be batch or continuous-flow, using fixed catalyst beds and slurries. In batch mode, dispersed catalysts are currently based on Mo, Ni, and Fe compounds. Specifically, the use of dispersed catalysts containing Fe leads to a reduction in coking, which is explained by Petr Yeletsky et al. in "Catalytic steam cracking of heavy oil feedstocks", Catalyst in Industry, 2018, vol. 10, No. 3, pp. 185-201, by the ability of iron salts to promote hydrogen transfer from hydrogen-saturated hydrocarbon molecules to newly formed hydrocarbon radicals and electron transfer between organic compounds due to a possible change in oxidation state. Fe 2+ Fe 3+ Hydrogen transfer to Fe leads to saturation of hydrocarbon radicals. 3+ Fe 2+The ability of the catalyst to be reduced to HCl can lead to improved stability of the hydrocarbon radicals, making them less likely to participate in polycondensation. Heterogeneously supported catalysts, such as red mud modified with ZrO2, can be used in batch mode. In continuous flow mode, catalytic steam cracking can be complicated by the hydrodynamic resistance of the catalyst bed and rapid deactivation of the catalyst (due to poisoning or coking). To prevent this, slurry reactors use dispersed catalysts as disclosed in this embodiment, and in some embodiments, include the addition of an aromatic solvent. Iron compounds, such as hematite, which can be reduced to magnetite, can be beneficial in this approach (based on their redox chemistry described above).

[0020] In some embodiments, the catalyst composition disclosed herein can be based on one or more inorganic fine minerals, natural ancient mineral mixtures found in coal deposits, containing multiple transition metals, such as iron, copper, and manganese. The catalyst can also contain one or more of calcium, barium, magnesium, potassium, and sodium, which can act as promoters. One exemplary embodiment of the catalyst composition can be 30,100 ppm iron, 17,600 ppm calcium, 5,190 ppm magnesium, 2,980 ppm potassium, 1,920 ppm sulfur, 1,190 ppm nitrogen, 253 ppm manganese, 139 ppm phosphorus, 93 ppm zinc, 43 ppm copper, and 2 ppm molybdenum. The bulk mineralogical analysis (XRD, XRF) of the fine minerals comprising such a catalyst is shown in Table 1 below: [Table 1]

[0021] In some embodiments, mineral oxides such as Al2O3, BaO, CaO, Fe2O3, MgO, P2O5, K2O, Na2O, TiO2, MnO2 may also be present in the finely divided mineral composition.

[0022] Some of the sedimentary clays that make up the fine mineral matter may contain porous structures and water of hydration, as well as zeolite minerals that can act as chemical catalysts. 2+ , Mg 2+ , Na + , K. + From Fe 2+ , Fe 3+ , Cu + , Cu 2+ , Mn 2+ and / or Mn 3+ , which are loosely held and readily available to exchange with others and participate in electron transfer reactions.

[0023] The bonds in minerals shown in Table 1 can be either ionic or covalent in nature, resulting in a variety of configurations, symmetries, charges, and bonding properties. The ligand field approach is most applicable because it involves ions or molecules surrounding a central atom or ion, with the resulting strength of the ligand field being the controlling factor. Charge transfer processes also occur in ligand field situations and can lead to photochemical oxidation and reduction.

[0024] The fine mineral matter contains at least one, more preferably at least two, transition metals selected from the group consisting of Fe, Cu, Mn, Mo, Zn, and / or Co. The concentrations of metals and metal salts in the fine mineral matter depend on the analytical method used and are typically measured by X-ray techniques: fluorescence (XRF) and diffraction (XRD) and inductively coupled plasma-acid-atomic analysis (ICP-AES). The transition metals in the fine mineral matter are measured using the ICP-AES method in a heated digester using nitric acid, hydrochloric acid, and hydrogen peroxide and have concentrations defined in the ranges shown in Table 2: [Table 2]

[0025] In some embodiments, the finely divided mineral matter further comprises a promoter that is an alkali metal / alkaline earth metal. Non-limiting examples of such promoters can include Ca, K, Mg, or combinations thereof to promote the oxidative degradation of plastics. The promoter in the finely divided mineral matter has a concentration defined by the ranges shown in Table 3. Other alkali / alkaline earth-containing minerals with similar fractions of soluble cations can also be used as promoters for oxidative degradation.

[0026] [Table 3]

[0027] Other elements identified by ICP-AES are shown in Table 4: [Table 4]

[0028] In some embodiments, the concentration of the catalytic fine mineral matter can depend on the type of reactor. For example, in a continuous fluidized bed reactor, the catalyst to feed ratio can range from about 1:5 to about 1:100 wt.%, and in some embodiments, the range can be from about 1:10 to about 1:70 wt.%. In a batch reactor, the catalyst concentration can range from about 0.5 to about 30 vol.%, and in some embodiments, the range can be from about 0.5 to 8 vol.%.

[0029] The fine mineral matter can be separated by froth flotation techniques or similar processes known to those skilled in the art and has a particle size generally ranging from less than about 50 μm to about 2 μm, although in some embodiments the particle size may range from about 0.5 to about 20 μm. In some embodiments, finer fractions can be used, such as from about 5 μm to about 0.5 μm, or from about 2 μm to about 0.5 μm.

[0030] The proposed catalyst enhances polymer chain scission and oxidative conversion, increasing the yield of CO, CO2 in the thermocatalytic cracking of petrochemical heavy oil feedstocks and / or alkanes, mixed plastic solid waste, or post-industrial or post-consumer plastic waste as discussed above. Transition metal compounds can participate in redox processes in media containing both hydrocarbons and water, i.e., reduction of transition metal oxides with hydrocarbons (oxidative cracking) followed by reoxidation with water, which can be in the form of superheated steam or supercritical fluids. Hydrogen formed in situ during the reoxidation of the reduced compounds can saturate and enhance the quality of the liquid products.

[0031] The distribution of liquefaction products can be affected by the presence of inherent mineral matter, with raw coal producing higher yields of benzene and pyridine solubles than demineralized coal. Under coal liquefaction conditions, hydrogen-donating solvents (e.g., tetralin) donate their hydrogen to coal-derived free radicals (naphthalene is the primary product of solvent dehydrogenation).

[0032] In embodiments disclosed herein, the free radicals generated from heavy oil or mixed plastic feedstocks are not terminated with hydrogen donor compounds, but rather participate in hydrogen abstraction, promoting the unzipping of additional chains of high molecular weight hydrocarbons in an oxygen-rich environment.

[0033] Those skilled in the art will recognize that more severe process conditions (requiring higher temperatures and / or pressures) typically lead to a higher proportion of aromatics. In the presence of a catalyst, for example, severity can be minimized, and the composition of the molecules produced can be made more homogeneous, with a lower proportion of aromatics. Complete conversion at low temperatures can simplify subsequent electrical conduction, which in some embodiments can be utilized instead of and / or in addition to combustion.

[0034] The use of the catalysts disclosed herein can promote partial oxidation, low-temperature partial steam reforming, and catalytic cracking, significantly increasing the efficiency of cracking and steam reforming / gasification processes. Water can be used in the form of steam, superheated steam, or supercritical fluid. Cracking involving supercritical water is highly effective in the presence of a catalyst because, unlike ordinary water, supercritical water is nearly nonpolar and a good solvent for hydrocarbons. Supercritical water can also disperse high-molecular-weight hydrocarbons that are not easily soluble or insoluble through the formation of emulsions, which leads to a reduction in the yield of coke and an increase in the yield of liquid products. Supercritical water can increase the efficiency of oxidative cracking by promoting the partial oxidation of hydrocarbons and leads to the formation of additional hydrogen.

[0035] It will be appreciated that in some embodiments, the disclosed catalysts do not undergo thermal decomposition. Rather, in some embodiments, the catalysts disclosed herein allow steam cracking, reforming, and gasification processes to be carried out under reduced process severity conditions, i.e., temperature, pressure, and energy consumption. The catalysts have been shown to reduce the activation energy for the decomposition of polyolefin-based feedstocks when the decomposition is carried out in an oxidizing environment, such as air. TGA data, as further described below, demonstrate a reduction in the activation energy for the thermal decomposition of PE feedstocks in the presence of the described minerals. For example, in some embodiments, the activation energy can be reduced from 43 to 23 kJ / mol using about 2% of the fine mineral matter.

[0036] The catalyst can function both in situ and in post-gasification reactions. The former can involve impregnating the catalyst into the feedstock prior to gasification. It can be added directly to the reactor, such as a fluidized bed. In post-gasification reactions, the catalyst is placed in a second reactor downstream of the gasifier (guard bed reactor) to convert the tar and methane formed, which has the added advantage of being independent of the gasifier operating conditions. The second reactor can be operated at the optimum temperature for the reforming reaction.

[0037] Some non-limiting examples of processes that can be used and / or improved using the catalysts disclosed herein include: (1) the KDV process (catalytic pressureless depolymerization process), (2) the Texaco process, which utilizes fluidized bed, fixed bed, and entrained flow reactors, and (3) the desulfurization of coal sulfur compounds, with or without the addition of other catalytic compounds. Additional processes that can benefit from the catalysts disclosed herein are summarized below:

[0038] Epoxidation of olefinic alcohols: The use of vanadium and molybdenum for the epoxidation of simple olefins with alkyl hydroperoxides is known, but has not been utilized for the synthesis of complex molecules. The use of catalysts based on finely divided minerals may provide a more effective and affordable approach.

[0039] Conversion of synthesis gas to methanol: The proposed catalyst may also provide for further optimization of the catalytic synthesis of methanol from synthesis gas, which is currently the most common method for the industrial production of methanol. Current catalysts for the catalytic conversion of synthesis gas to methanol are based on ZnO / Al2O3 (BASF process) or Cu / ZnO / Al2O3 (ICI process).

[0040] Methanol-to-gasoline (MTG) conversion: Methanol-to-gasoline synthesis, developed by Mobil Oil Corporation, catalytically converts methanol to hydrocarbons over a zeolite catalyst (NaAlSiO·H₂O) at 350°C and a pressure of about 30 atm. A similar "coal-to-gasoline" process was developed in China by the Jincheng Anthracite Mining Group.

[0041] Methanol to Olefins (MTO): The MTO process converts methanol to light olefins. Unlike steam cracking, the propylene yield relative to ethylene is more flexible, which is a strong advantage over steam cracking. This process currently requires higher temperatures than MTG, but at near atmospheric pressure.

[0042] In some embodiments, a combination of technologies, such as a liquefaction stage and an entrained or fixed-bed or fluidized-bed gasifier, can also be used. In the liquefaction stage, plastic waste can be thermally gently cracked (depolymerized) into synthetic heavy oil and several condensable and non-condensable gas fractions. The non-condensable gases can be reused as fuel (along with natural gas) in the liquefaction. The oil and condensable gases can be injected into a gasifier, where gasification occurs using oxygen and steam. After a number of cleaning processes, which may include, among others, the removal of HCl and HF, clean and dry synthesis gas, consisting primarily of CO and H, is produced, along with small amounts of CH, CO, HO, and some inert gases. Typical gasification is generally carried out in the temperature range of 1200°C to 1500°C, although those skilled in the art will recognize that higher or lower temperatures can be applied to facilitate gasification, which is essentially the Texaco process described above. It will be understood that the Texaco process requires high temperatures to facilitate conversion.

[0043] The chemical recycling process begins in S1, where a quantity of fine mineral matter is obtained that can be used as a catalyst. The fine mineral matter is separated from coal waste and / or fine-sized coal using the froth flotation process described above. The fine mineral matter can also be mined from natural sources, such as volcanic basalt, glacial debris deposits, potassium iron silicate, and / or other coastal mining deposits. The particle size of the fine mineral matter ranges from less than about 50 μm to about 2 μm. The fine mineral matter contains at least one, and more preferably at least two, transition metals selected from the group consisting of Fe, Cu, Mn, Mo, Zn, Co, or combinations thereof to cause oxidative degradation of non-biodegradable plastics. The transition metals in the fine mineral matter are measured using ICP-AES in a heated digester using nitric acid, hydrochloric acid, and hydrogen peroxide, and have concentrations defined within the ranges shown in Table 2 above.

[0044] In some embodiments, heating can be carried out at a temperature ranging from about 200 degrees Celsius to about 500 degrees Celsius.

[0045] The fine mineral matter further contains Ca, K, Mg or a combination thereof to promote the oxidative degradation of plastics.

[0046] In step S2, the fine mineral matter is contacted with the molten polymer or polymer vapor formed during cracking. Contact with the fine mineral matter can be carried out in the presence of oxygen and / or water vapor at cracking or gasification temperatures to produce synthesis gas rich in H and CO, along with smaller amounts of CH, CO, HO and some inert gases.

[0047] In step S3, transition metals in the fine mineral matter catalyze oxidative degradation. For hydrocarbon-based polymers susceptible to radical chain processes, the rate-limiting part of the degradation process is the oxidation segment, commonly referred to as peroxidation. Hydrocarbon polymers vary in their ability to withstand (or undergo) peroxidation. Thus, oxidative stability increases from natural rubber (cis-poly(isoprene)) to poly(butylene), polypropylene, polyethylene, and polyvinyl chloride. Among polyethylenes, LDPE and LLDPE are more susceptible to oxidative degradation than HDPE due to their chemical and morphological properties. [Example]

[0048] Experimental data Samples of linear low density polyethylene (LLDPE) and LLDPE modified with the catalysts disclosed herein were tested in air from 50°C to 550°C at rates of 5, 10, 15 and 20°C / min using a TA Instruments Discovery Thermogravimetric Analysis (TGA) analyzer. The activation energies for decomposition were calculated by the Kissinger method:

number

[0049] In the above formula, α is the conversion rate, E a is the apparent activation energy, kJ / mol; A is the frequency factor; β is the heating rate, °C / min; R is the universal gas constant, J / mol°K; T m is the temperature at which the decomposition rate reaches its maximum, °K, and n is the reaction order. The Kissinger method uses the product n(1-α) m n-1 is equal to 1 and is independent of the heating rate. a / RT m 2 )=-E a / RT m Rewritten as ln(β / Tm 2 ) of (1 / RT m) is found to be linear. The apparent activation energy is calculated from the slope, and the frequency factor from the intercept of the line on the y-axis.

[0050] Figures 2-5 illustrate the effect that the addition of a catalyst can have on LLDPE. As shown in Figure 2, the E of the decomposition of the base LLDPE compound in air a is 43.4 kJ / mol. The base LLDPE compound also contains 0.2% phenolic primary antioxidant and 0.13% benzotriazole UV absorber. The addition of catalyst to the base LLDPE compound increases E a to 20.85 kJ / mol. Thus, the inclusion of a catalyst reduces the activation energy E a Those skilled in the art will recognize that "fmm" in the drawings refers to "fine mineral matter." a The TGA data for the base LLDPE and modified LLDPE samples used in the calculation of is shown in Figures 4 and 5. As shown in Figure 4 for the base LLDPE, degradation is shown at 5 C / min (A), 10 C / min (B), 15 C / min (C), and 20 C / min (D).

[0051] For cracking carried out in nitrogen, the activation energies for base LLDPE and modified LLDPE are 107.83 and 156.44 kJ / mol, respectively. These values ​​suggest that the fine mineral matter catalyzes the oxidation process, and chemical recycling techniques involving oxidation should be considered. Some non-limiting examples of such techniques could be gasification, thermal cracking, or catalytic cracking carried out in the presence of oxygen or other oxidizing environments.

[0052] In some embodiments, when LDPE compounds with different stabilization chemistries are tested by TGA, a reduction in activation energy in compounds modified with fine mineral matter is also demonstrated, dropping from 51.6 to 45.7 kJ / mol with the use of only 0.5% of said mineral matter.

[0053] A summary table of TGA data for the thermal degradation of LDPE and LLDPE for various materials is shown in Table 5 below.

[0054] [Table 5]

[0055] Those skilled in the art will appreciate further features and advantages of the present disclosure based on the above-described embodiments. Accordingly, the present disclosure is not to be limited by what has been particularly shown and described, except as indicated by the appended claims. All cited publications and references are expressly incorporated herein by reference in their entirety.

Claims

1. obtaining a quantity of catalytic fine mineral matter separated from coal, said catalytic fine mineral matter being sedimented clay having a particle size in the range of 2 μm to 50 μm; contacting a feedstock comprising a molten polymer or vapor thereof with said catalytic fine mineral matter in the presence of oxygen and / or water vapor at cracking or gasification temperatures to form a synthesis gas product, wherein said molten polymer or vapor thereof is converted into smaller molecules after contact with said fine mineral matter. and the smaller molecule comprises H 2 , CO, CH 4 , CO 2 , H 2 and one or more of O and an inert gas, and the catalytic fine mineral matter comprises at least one transition metal selected from the group consisting of Cu, Mn, Mo, Zn, Co or a combination thereof, and Fe in the following concentrations: Fe 14,000-45,000ppm, Cu 10-50ppm, Mn 100-700ppm, Mo 1 to 2 ppm, Zn 20-120 ppm, and Co at 10 to 15 ppm, and The catalytic fine mineral matter contains one or more of the alkali and alkaline earth metals Ca, K, Na, Mg or combinations thereof in the following concentrations: Ca 1,000-18,000ppm, K 600-4,000ppm, Na 300 to 1,500 ppm, and Mg 20-8,000ppm Further included are chemical recycling methods.

2. 2. The method of claim 1, wherein ppm is measured using an ICP-AES method in a heated digester utilizing nitric acid, hydrochloric acid, and hydrogen peroxide.

3. 2. The process of claim 1, wherein the concentration of the catalytic mineral fines is in the range of 1:5 to 1:100 mass % catalyst / feed ratio.

4. 10. The method of claim 1, wherein the catalytic fine mineral matter is utilized as a catalyst.

5. 10. The method of claim 1, wherein liquefaction precedes gasification and is achieved via pyrolysis, or thermal cracking or steam cracking, to convert the plastic waste into synthetic heavy oil and condensable gases, which are injected into the gasifier and / or steam reformer.

6. 10. The method of claim 1 further comprising, following gasification, washing and / or hydrogenation to improve the composition of the synthesis gas product.

7. 10. The method of claim 1, further comprising subjecting the synthesis gas product to one or more of processes utilizing single or double column fluidized bed, fixed bed and entrained flow reactors.

8. 10. The method of claim 1, wherein the cracking is steam cracking, the steam cracking comprising hydrothermal decomposition in supercritical water.

9. 10. The method of claim 1, further comprising using the synthesis gas product as a heat source to promote steam cracking or gasification.

10. 10. The method of claim 1, further comprising using the synthesis gas product as a gas source to support hydrocracking.

11. 2. The process according to claim 1, wherein the catalytic steam cracking is batch or continuous flow (slurry type).

12. 10. The method of claim 9, wherein the heating is carried out at a temperature in the range of 200 degrees Celsius to 500 degrees Celsius.

13. 10. The method of claim 1, wherein the catalytic fine mineral material enhances chain scission or oxidative conversion of the molten polymer or its vapors.

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