Catalytic pyrolysis of plastics to produce petrochemical feedstocks

Abstract

This technology generally relates to catalyst compositions comprising a mesoporous active matrix and phosphorus-stabilized ZSM-5, and methods for preparing such compositions and using them in fluidized bed or conical sputtered bed reactors to catalytically pyrolyze plastics into olefins and aromatic compounds. Methods for catalytically pyrolyzing plastics (e.g., waste plastics) using such compositions provide petrochemical feedstocks such as ethylene, propylene, and butene with high gasification rates and better selectivity.

Description

[0001] Cross-reference to related applications This application claims priority to U.S. Patent Application No. 63 / 580,579, filed September 5, 2023, the contents of which are incorporated herein by reference in their entirety.

[0002] field This technology generally relates to the conversion of plastics into olefins and aromatic compounds via pyrolysis. Specifically, this technology relates to catalyst compositions comprising a mesoporous active matrix and phosphorus-stabilized ZSM-5, and methods for preparing such compositions and using such compositions in fluidized bed or conical sputtered bed reactors to catalytically pyrolyze plastics into olefins and aromatic compounds.

[0003] background Catalytic pyrolysis represents an attractive method for recycling plastic waste, involving the degradation of polymeric materials by heating them in the absence of oxygen and in the presence of a catalyst. Silica-alumina, zeolite, and fluidized bed catalytic cracking (FCC) catalysts are commonly used to lower energy barriers, influence the composition of cracking products, and reduce process time. Despite extensive research into catalytic pyrolysis, there remains a need to develop more efficient catalytic pyrolysis methods to maximize the yields of desired products (such as light olefins and aromatic compounds) and minimize the yields of undesirable products (such as methane and ethane). In particular, propylene is a specific light olefin with high demand due to its use in many of the world's largest and fastest-growing synthetic materials and thermoplastics.

[0004] This disclosure provides catalyst compositions comprising a mesoporous active matrix and phosphorus-stabilized ZSM-5, as well as methods for preparing such compositions and for using such compositions in fluidized bed or conical sputtered bed reactors to catalytically pyrolyze plastics into olefins and aromatic compounds. Methods for catalytically pyrolyzing plastics (e.g., waste plastics) using such compositions provide petrochemical feedstocks such as ethylene, propylene, and butene with high gasification rates and better selectivity.

[0005] Overview In one aspect, a catalyst composition comprises: Mesoporous active matrix; and Phosphorus-stabilized ZSM-5.

[0006] In some embodiments, the mesoporous active matrix comprises one or more of kaolin and soluble alumina. In some embodiments, the catalyst composition comprises more than about 30% of one or more of kaolin and soluble alumina based on the total weight of the catalyst composition.

[0007] In some embodiments, the catalyst composition comprises more than about 10% colloidal alumina based on the total weight of the catalyst composition. In some embodiments, the catalyst composition comprises more than about 30% colloidal alumina based on the total weight of the catalyst composition. In some embodiments, the catalyst composition comprises from about 10% to about 70% colloidal alumina based on the total weight of the catalyst composition.

[0008] In some embodiments, the mesoporous active matrix comprises pores with a pore size of about 20 Å to about 600 Å, or about 40 Å to about 600 Å. In some embodiments, the mesoporous active matrix comprises pores with a pore size greater than about 600 Å.

[0009] In some embodiments, the mesoporous active matrix has approximately 50 μm of surface area before deactivation. 2 / g to approximately 250 m 2 / g surface area. In some embodiments, the mesoporous active matrix has approximately 60 m² / g surface area before deactivation. 2 / g to approximately 200 m 2 / g, approximately 80 m 2 / g to approximately 150 m 2 / g, or approximately 90 m 2 / g to approximately 120 m 2 / g of surface area.

[0010] In some embodiments, the mesoporous active matrix has a pore volume greater than about 0.01 cc / g. In some embodiments, the mesoporous active matrix has a pore volume from about 0.1 cc / g to about 0.4 cc / g.

[0011] In some embodiments, the catalyst composition comprises more than about 5% w / w of phosphorus-stabilized ZSM-5 based on the total weight of the catalyst composition. In some embodiments, the catalyst composition comprises from about 5% to about 70% phosphorus-stabilized ZSM-5 based on the total weight of the catalyst composition.

[0012] In some embodiments, the phosphorus-stabilized ZSM-5 further comprises one or more metals selected from iron, copper, zinc, nickel, titanium, vanadium, chromium, manganese, cobalt, gallium, and boron. In some embodiments, the phosphorus-stabilized ZSM-5 has a crystallite size of approximately 0.05 micrometers to approximately 2 micrometers.

[0013] In some embodiments, the catalyst composition contains approximately 0.5% w / w to approximately 15% w / w P2O5 based on the total weight of the composition.

[0014] In some embodiments, phosphorus-stabilized ZSM-5 and mesoporous active matrix are separated particles in the catalyst composition.

[0015] In another aspect, a method for preparing a catalyst composition is provided, the method comprising: (a) Provide an aqueous slurry A containing solid particles of phosphorus-stabilized pentasil zeolite; (b) Slurry A is combined with colloidal alumina, kaolin and alumina sol to provide slurry B; (c) Spray-drying slurry B to form catalyst particles; and (d) Calcining the spray-dried catalyst particles at a temperature and time sufficient to remove volatiles and recover the catalyst composition; in: The catalyst composition comprises a mesoporous active matrix and phosphorus-stabilized pentasil zeolite.

[0016] In some embodiments, the method further includes washing the calcined catalyst particles with water and an ammonia solution with a pH of about 3 to about 7.5.

[0017] In some embodiments, the phosphorus-stabilized pentasil zeolite is phosphorus-stabilized ZSM-5. In some embodiments, the phosphorus-stabilized ZSM-5 is prepared by any stabilization method, such as impregnation with a suitable phosphorus compound such as H3PO4, (NH4)H2PO4, (NH4)2HPO4, and (NH4)3PO4 by slurry addition, spray drying, and optionally grinding ZSM-5 particles; drying at a temperature of about 120°C; and calcination at about 600°C for about 1 hour. In some embodiments, the phosphorus-stabilized ZSM-5 is derived from commercially available ZSM-5.

[0018] In some embodiments, the aqueous slurry A contains solid particles of phosphorus-stabilized ZSM-5 in an amount sufficient to provide a catalyst composition containing more than about 5% w / w of phosphorus-stabilized ZSM-5 based on the total weight of the catalyst composition.

[0019] In some embodiments, the aqueous slurry B contains soluble alumina in an amount sufficient to provide a catalyst composition containing more than about 10% w / w of soluble alumina based on the total weight of the catalyst composition.

[0020] In some embodiments, the alumina sol exists in the slurry in an amount sufficient to bind the catalyst comprising about 5% to about 50% alumina based on the total weight of the catalyst composition.

[0021] In some implementations, spray drying provides catalyst particles with a particle size of about 20 micrometers to about 200 micrometers.

[0022] In another aspect, a method is provided for producing at least one or more of olefins and aromatic compounds from plastic raw materials, the method comprising: In a fluidized bed or conical sputtered bed reactor, the plastic feedstock and any of the catalyst compositions described herein are contacted for a sufficient time at a temperature of about 400°C to about 700°C and in an oxygen-deficient environment (such as a low-oxygen or anaerobic environment) to allow at least a portion of the plastic feedstock to be converted into a product stream comprising olefins, aromatic compounds, or mixtures of olefins and aromatic compounds.

[0023] In some embodiments, the contact between the plastic raw material and the catalyst composition is carried out at a temperature of about 500°C to about 600°C.

[0024] In some embodiments, the plastic raw material includes at least one of polyethylene, polypropylene, polystyrene, polyethylene terephthalate (PET), polyvinyl chloride (PVC), polyamide, polycarbonate, polyurethane, polyester, natural and synthetic rubber, tires, filler polymers, composite materials, plastic alloys, and plastics dissolved in solvents.

[0025] In some embodiments, the plastic raw material comprises polyethylene, such as LLDPE and HDPE. In some embodiments, the plastic raw material comprises polypropylene, such as HPP.

[0026] In some embodiments, the product stream contains olefins, including ethylene, propylene, butene, or any two or more of these. In some embodiments, the product stream contains from about 15% by weight to about 60% by weight of olefins, such as ethylene, propylene, and butene.

[0027] In some embodiments, the product stream contains aromatic compounds, including benzene, toluene, xylene, or a mixture of any two or more of these.

[0028] In some embodiments, the method uses a conical spouted bed reactor that includes inlet pipes and restrictors. In some embodiments, the method uses a fluidized bed reactor. Brief description of the attached diagram Figure 1 This is a schematic diagram of a conventional sputtered bed reactor from existing technology.

[0030] Figure 2 This is a schematic diagram of a spouted bed reactor with a flow inlet and a limiter according to an exemplary embodiment.

[0031] Figure 3These are schematic diagrams of two exemplary embodiments of a drainage tube having open and closed sidewalls.

[0032] Figure 4 This is a schematic diagram of the arrangement of the drainage tube and restrictor with the dimensions shown.

[0033] Detailed Explanation Various implementation schemes are described below. It should be noted that the specific implementation schemes are not intended as an exhaustive description or as a limitation on the broader aspects discussed herein. An aspect described in conjunction with a particular implementation scheme is not necessarily limited to that scheme and can be implemented with any other implementation scheme.

[0034] As used herein, “approximately” will be understood by those skilled in the art and will vary to some extent depending on the context in which it is used. If those skilled in the art are unaware of the use of this term, “approximately” will, in light of the context in which it is used, mean at most + or -10% of a particular item.

[0035] Unless otherwise stated herein or clearly contrary to the context, the use of the terms “a,” “an,” “the,” and similar indicators in the context of describing elements (especially in the context of the following claims) should be interpreted as covering both singular and plural. Unless otherwise stated herein, the enumeration of numerical ranges herein is intended only to serve as a shorthand for referring one by one to each individual numerical value falling within that range, and each individual numerical value is incorporated into this specification as if enumerated one by one herein. Unless otherwise stated herein or clearly contrary to the context, all methods described herein may be performed in any suitable order. Unless otherwise stated, the use of any and all instances or exemplary wording (e.g., “such as”) provided herein is intended only to better elucidate the embodiments and not to limit the scope of the claims. None of the wording in the specification should be construed as indicating that any unclaimed element is essential.

[0036] This document discloses catalyst compositions comprising a mesoporous active matrix and phosphorus-stabilized ZSM-5, as well as methods for preparing and using such compositions. Specifically, the catalyst compositions described herein can be used in fluidized bed reactors or conical spouted bed reactors including inlet tubes and limiters to convert waste plastics into valuable petrochemical feedstocks such as ethylene, propylene, and butene in high yields. These petrochemical feedstocks can then be reprocessed into usable plastics for a more circular economy.

[0037] As demonstrated in the examples, an advantage of using the compositions disclosed herein for the catalytic pyrolysis of plastics (e.g., waste plastics) is the high gasification rate of the polymer in combination with ZSM-5, which provides better selectivity. Under certain conditions using an optimal catalyst, these advantages result in higher yields of light olefins. For example, in Example 12, the HDPE embodiment exhibited a lower yield but still a high gasification rate; and in Example 16, the maximum yield of light olefins was achieved by optimizing the phosphorus input with a high ZSM-5 loading.

[0038] ZSM-5 catalyst composition The catalyst composition described herein includes a mesoporous active matrix and a phosphorus-stabilized ZSM-5.

[0039] The mesoporous active matrix described herein is a catalytically active porous silica-alumina material; however, unlike zeolites, it is amorphous and non-crystalline. Furthermore, the mesoporous active matrix described herein is acidic (e.g., silica / alumina, or alumina, etc.). The acidity of the mesoporous active matrix can be determined by diffuse reflectance pyridine IR as a Lewis acid or Brønsted acid. In some embodiments, the acidity of the mesoporous active matrix is ​​not reduced by AlPO4.

[0040] The mesoporous active matrix described herein comprises one or more of kaolin and soluble alumina. In some embodiments, the mesoporous active matrix comprises one or more of kaolin and soluble alumina. In some embodiments, the catalyst composition comprises more than about 30% of one or more of kaolin and soluble alumina based on the total weight of the catalyst composition. In some embodiments, the catalyst composition comprises from about 30% to about 70% of one or more of kaolin and soluble alumina based on the total weight of the catalyst composition. In some embodiments, the catalyst composition comprises about 30%, about 35%, about 40%, about 45%, about 50%, about 55%, about 60%, about 65%, and about 70% of one or more of kaolin and soluble alumina based on the total weight of the catalyst composition.

[0041] In some embodiments, the catalyst composition comprises more than about 10% colloidal alumina based on the total weight of the catalyst composition. In some embodiments, the catalyst composition comprises more than about 30% colloidal alumina based on the total weight of the catalyst composition. In some embodiments, the catalyst composition comprises from about 10% to about 70% colloidal alumina based on the total weight of the catalyst composition. In some embodiments, the catalyst composition comprises about 10%, about 15%, about 20%, about 25%, about 30%, about 35%, about 40%, about 45%, about 50%, about 55%, about 60%, about 65%, and about 70% colloidal alumina based on the total weight of the catalyst composition.

[0042] In some embodiments, the mesoporous active matrix comprises pore sizes of about 20 Å to about 600 Å or about 40 Å to about 600 Å, including about 20 Å, about 30 Å, about 40 Å, about 50 Å, about 60 Å, about 70 Å, about 80 Å, about 90 Å, about 100 Å, about 110 Å, about 120 Å, about 130 Å, about 140 Å, about 150 Å, about 170 Å, about 180 Å, about 190 Å, about 200 Å, about 210 Å, about 220 Å, about 230 Å, about 240 Å, about 250 Å, about 260 Å, about 270 Å, about 280 Å, about 290 Å, about 300 Å, about 310 Å, about 320 Å, and about 330 Å. Pores of approximately 340 Å, approximately 350 Å, approximately 360 Å, approximately 370 Å, approximately 380 Å, approximately 390 Å, approximately 400 Å, approximately 410 Å, approximately 420 Å, approximately 430 Å, approximately 440 Å, approximately 450 Å, approximately 460 Å, approximately 470 Å, approximately 480 Å, approximately 490 Å, approximately 500 Å, approximately 510 Å, approximately 520 Å, approximately 530 Å, approximately 540 Å, approximately 550 Å, approximately 560 Å, approximately 570 Å, approximately 580 Å, approximately 590 Å, and approximately 600 Å.

[0043] In some embodiments, the mesoporous active matrix comprises pores (e.g., macropores) with a pore size greater than about 600 Å. In some embodiments, the mesoporous active matrix comprises pores with a pore size from about 600 Å to about 10,000 Å, including pores of about 600 Å, about 700 Å, about 800 Å, about 900 Å, about 1,000 Å, about 2,000 Å, about 3,000 Å, about 4,000 Å, about 5,000 Å, about 6,000 Å, about 7,000 Å, about 8,000 Å, about 9,000 Å, and about 10,000 Å. In some embodiments, the mesoporous active matrix comprises pores with a pore size from about 600 Å to about 1,000 Å, including pores of about 600 Å, about 700 Å, about 800 Å, about 900 Å, and about 1,000 Å.

[0044] In some embodiments, the mesoporous active matrix comprises pores with a pore size of about 1,000 Å to about 10,000 Å, including pores of about 1,000 Å, about 2,000 Å, about 3,000 Å, about 4,000 Å, about 5,000 Å, about 6,000 Å, about 7,000 Å, about 8,000 Å, about 9,000 Å, and about 10,000 Å.

[0045] The mesoporous active matrix described in this article has a density of approximately 50 μm before deactivation. 2 / g to approximately 250 m 2 / g surface area, wherein the surface area is determined by the N2-BET (Brunauer, Emmett and Teller) method, and the porosity and pore size distribution are measured by mercury porosimetry. In some embodiments, the mesoporous active matrix has approximately 50 μm² of surface area before deactivation. 2 / g to approximately 250 m 2 / g, including approximately 50 m before deactivation. 2 / g, approximately 60 m 2 / g, approximately 70 m 2 / g, approximately 80m 2 / g, approximately 90 m 2 / g, approximately 100 m 2 / g, approximately 110 m 2 / g, approximately 120 m 2 / g, approximately 130 m 2 / g, approximately 140m 2 / g, approximately 150 m 2 / g, approximately 160 m 2 / g, approximately 170 m 2 / g, approximately 180 m 2 / g, approximately 190 m2 / g, approximately 200m 2 / g, approximately 210 m 2 / g, approximately 220 m 2 / g, approximately 230 m 2 / g, approximately 240 m 2 / g and approximately 250 m 2 / g surface area. In some embodiments, the mesoporous active matrix has approximately 60 m² / g surface area before deactivation. 2 / g to approximately 200 m 2 / g, approximately 80m 2 / g to approximately 150 m 2 / g, or approximately 90 m 2 / g to approximately 120 m 2 / g of surface area.

[0046] In some embodiments, the mesoporous active matrix has a pore volume greater than about 0.01 cc / g. In some embodiments, the mesoporous active matrix has a pore volume from about 0.1 cc / g to about 0.4 cc / g, including about 0.1 cc / g, about 0.15 cc / g, about 0.2 cc / g, about 0.25 cc / g, about 0.3 cc / g, about 0.35 cc / g, and about 0.4 cc / g.

[0047] In some embodiments, the catalyst composition comprises more than about 5% w / w of phosphorus-stabilized ZSM-5 based on the total weight of the catalyst composition. In some embodiments, the catalyst composition comprises from about 5% to about 70% phosphorus-stabilized ZSM-5 based on the total weight of the catalyst composition. In some embodiments, the catalyst composition comprises about 5%, about 10%, about 15%, about 20%, about 25%, about 30%, about 35%, about 40%, about 45%, about 50%, about 55%, about 60%, about 65%, and about 70% phosphorus-stabilized ZSM-5 based on the total weight of the catalyst composition.

[0048] In some embodiments, the phosphorus-stabilized ZSM-5 further comprises one or more metals selected from iron, copper, zinc, nickel, titanium, vanadium, chromium, manganese, cobalt, gallium, and boron.

[0049] In some embodiments, ZSM-5 has crystallite sizes ranging from about 0.05 micrometers to about 2 micrometers, including about 0.05 micrometers, about 0.06 micrometers, about 0.07 micrometers, about 0.08 micrometers, about 0.09 micrometers, about 0.1 micrometers, about 0.2 micrometers, about 0.3 micrometers, about 0.4 micrometers, about 0.5 micrometers, about 0.6 micrometers, about 0.7 micrometers, about 0.8 micrometers, about 0.9 micrometers, about 1 micrometer, about 1.5 micrometers, and about 2 micrometers.

[0050] Based on the total weight of the composition, the catalyst composition described herein may comprise from about 0.5% w / w to about 15% w / w P2O5. In some embodiments, based on the total weight of the composition, the catalyst composition comprises about 0.5% w / w, about 1% w / w, about 2% w / w, about 3% w / w, about 4% w / w, about 5% w / w, about 6% w / w, about 7% w / w, about 8% w / w, about 9% w / w, about 10% w / w, about 11% w / w, about 12% w / w, about 13% w / w, about 14% w / w, or about 15% w / w of P2O5.

[0051] In some embodiments, phosphorus-stabilized ZSM-5 and mesoporous active matrix are separated particles in the catalyst composition.

[0052] In another aspect, a method for preparing a catalyst composition is provided, the method comprising: (a) Provide an aqueous slurry A containing solid particles of phosphorus-stabilized pentasil zeolite; (b) Slurry A is combined with colloidal alumina, kaolin and alumina sol to provide slurry B; (c) Spray-drying slurry B to form catalyst particles; and (d) Calcining the spray-dried catalyst particles at a temperature and time sufficient to remove volatiles and recover the catalyst composition; in: The catalyst composition comprises a mesoporous active matrix and phosphorus-stabilized pentasil zeolite.

[0053] In some embodiments, the method further includes washing the calcined catalyst particles with water and an ammonia solution with a pH of about 3.0 to about 7.5.

[0054] In some embodiments, the phosphorus-stabilized pentasil zeolite is phosphorus-stabilized ZSM-5. In some embodiments, the phosphorus-stabilized ZSM-5 is prepared by any stabilization method, such as impregnation with a suitable phosphorus compound such as H3PO4, (NH4)H2PO4, (NH4)2HPO4, and (NH4)3PO4 by slurry addition, spray drying, and optionally grinding ZSM-5 particles; drying at a temperature of about 120°C; and calcination at about 600°C for about 1 hour. In some embodiments, the phosphorus-stabilized ZSM-5 is derived from commercially available ZSM-5.

[0055] In some embodiments, the aqueous slurry A contains solid particles of phosphorus-stabilized ZSM-5 in an amount sufficient to provide a catalyst composition containing more than about 5% w / w of phosphorus-stabilized ZSM-5 based on the total weight of the catalyst composition.

[0056] In some embodiments, the aqueous slurry B contains soluble alumina in an amount sufficient to provide a catalyst composition containing more than about 10% w / w of soluble alumina based on the total weight of the catalyst composition.

[0057] In some embodiments, the alumina sol is present in the slurry in an amount sufficient to bind a catalyst comprising approximately 5% to approximately 50% alumina based on the total weight of the catalyst composition. In some embodiments, the alumina sol is present in the slurry in an amount sufficient to bind a catalyst comprising approximately 5%, approximately 10%, approximately 15%, approximately 20%, approximately 25%, approximately 30%, approximately 35%, approximately 40%, approximately 45%, and approximately 50% alumina based on the total weight of the catalyst composition.

[0058] In some embodiments, spray drying provides catalyst particles having particle sizes ranging from about 20 micrometers to about 200 micrometers, about 20 micrometers, about 30 micrometers, about 40 micrometers, about 50 micrometers, about 60 micrometers, about 70 micrometers, about 80 micrometers, about 90 micrometers, about 100 micrometers, about 110 micrometers, about 120 micrometers, about 130 micrometers, about 140 micrometers, about 150 micrometers, about 160 micrometers, about 170 micrometers, about 180 micrometers, about 190 micrometers, and about 200 micrometers.

[0059] Catalytic pyrolysis This document describes a method for producing at least one or more olefins and aromatic compounds from plastic raw materials, the method comprising: In a fluidized bed or conical sputtered bed reactor, the plastic feedstock and any of the catalyst compositions described herein are contacted for a sufficient time at a temperature of about 400°C to about 700°C and under an oxygen-deficient environment to allow at least a portion of the plastic feedstock to be converted into a product stream comprising olefins, aromatic compounds, or mixtures of olefins and aromatic compounds.

[0060] In some embodiments, the contact between the plastic raw material and the catalyst composition is carried out at a temperature of about 500°C to about 600°C, including about 525°C to about 575°C. In some embodiments, the contact between the plastic raw material and the catalyst composition is carried out at a temperature of about 400°C, about 410°C, about 420°C, about 430°C, about 440°C, about 450°C, about 460°C, about 470°C, about 480°C, about 490°C, about 500°C, about 510°C, about 520°C, about 530°C, about 540°C, about 550°C, about 560°C, about 570°C, about 580°C, about 590°C, about 600°C, about 610°C, about 620°C, about 630°C, about 640°C, or about 650°C. In some embodiments, the contact between the plastic raw material and the catalyst composition is carried out at a temperature of about 550°C.

[0061] The plastic raw materials described herein may include at least one of polyethylene, polypropylene, polystyrene, polyethylene terephthalate (PET), polyvinyl chloride (PVC), polyamide, polycarbonate, polyurethane, polyester, natural and synthetic rubber, tires, filled polymers, composite materials, plastic alloys, and plastics dissolved in solvents. In some embodiments, the plastic raw material includes polyethylene (e.g., high-density polyethylene (HDPE) and linear low-density polyethylene (LLDPE)). In some embodiments, the plastic raw material includes polypropylene (e.g., HPP).

[0062] For the catalytic method described herein, the product stream may include at least one or more olefins (e.g., light olefins) selected from ethylene, propylene, and butene. In some embodiments, the product stream contains more than about 15 wt%, about 20 wt%, about 25 wt%, about 30 wt%, about 35 wt%, about 40 wt%, about 45 wt%, about 50 wt%, about 55 wt%, or about 60 wt% of ethylene, propylene, and butene. In some embodiments, the product stream contains from about 15 wt% to about 60 wt% of ethylene, propylene, and butene. In some embodiments, the product stream contains about 15 wt%, about 20 wt%, about 25 wt%, about 30 wt%, about 35 wt%, about 40 wt%, about 45 wt%, about 50 wt%, about 55 wt%, about 60 wt%, about 65 wt%, or about 70 wt% of ethylene, propylene, and butene.

[0063] In some embodiments, the product stream contains aromatic compounds, including benzene, toluene, xylene, or a mixture of any two or more of these.

[0064] In some embodiments, the method uses a conical spouted bed reactor that includes inlet pipes and restrictors. In some embodiments, the method uses a fluidized bed reactor.

[0065] Conical Sprayed Bed Reactor The use of a spouted bed reactor for the pyrolysis of plastics has been disclosed; however, spouted bed reactors disclosed prior to this disclosure do not have inlet pipes or limiters.

[0066] Figure 1 This diagram shows a conventional conical spouted bed reactor disclosed in the prior art, without inlet pipes or restrictors. An inert gas, such as nitrogen or vapor, is introduced into the catalyst bed through orifices at the bottom of the reactor. The flowing gas forms a cylindrical path, or spout, through the catalyst bed. The catalyst entrained by the gas flowing through the spout is pushed above the surface of the catalyst bed and re-settles in a fountain shape. The catalyst moves downwards back to the bottom of the conical bed in the annulus region, thus completing the cycle. The rapid circulation of catalyst and reactants ensures good mixing in the reactor. The fountain is a region of low catalyst density, called the dilute phase, while the annulus is a region of high catalyst density, called the dense phase. In the absence of inlet pipes, some gas flows around the spout and through the annulus region.

[0067] In contrast, the catalytic pyrolysis method for plastic waste described herein uses a conical spouted bed reactor that includes inlet pipes and limiters. Figure 2 A schematic diagram of an exemplary implementation is shown. Figure 3Two examples of inlet tubes with open and closed sidewalls are shown. Gas flowing through the inlet tube creates a negative pressure region at the bottom, which draws the catalyst from the annular region and pushes it upwards along the inlet tube. A top-sealed restrictor redirects the catalyst downwards.

[0068] The guide tube directs gas through the nozzle, resulting in less gas passing through the annular region compared to a conventional nozzle-bed reactor. Therefore, the minimum jet velocity is significantly lower with the guide tube present than without it.

[0069] The limiter confines the dilute phase to a smaller volume through more turbulent mixing. The feedstock added to the limiter mixes rapidly with the catalyst. The higher collision frequency between the catalyst and the plastic results in faster heat transfer, melting of the plastic, and distribution of the molten plastic throughout the catalyst.

[0070] Figure 4 An exemplary embodiment showing the arrangement of the inlet tubes and restrictors with key dimensions is illustrated. The conical jet-flushed bed reactor has an inlet opening D. O The diameter D of the cylindrical section of the conical sputtered bed reactor C The limiter has a diameter D. G The drainage tube has H G The distance between the top and bottom of the drainage tube.

[0071] In some implementations, H G It can be approximately 3 to approximately 4 x D O Or approximately 1.5 to 2.5 x D O In some implementations, H G For approximately 2 x D O .

[0072] In some implementation schemes, D G It can be approximately 3 x D O Up to approximately 0.7 D C Or approximately 4 to approximately 6 x D O In some implementations, D G For approximately 5 x D O .

[0073] The invention, which is generally described herein, will be more readily understood by referring to the following embodiments, which are provided as examples and are not intended to limit the invention. Example

[0074] Background Example A The use of a sputtered bed reactor for plastic pyrolysis has been disclosed; however, sputtered bed reactors disclosed prior to this disclosure do not have inlet tubes or limiters. Furthermore, the catalyst used with these sputtered bed reactors is an extrudate containing approximately 20% to 25% fresh ZSM-5 and has not been deactivated to simulate commercial performance.

[0075] A schematic diagram of a conventional conical spouted bed reactor without inlet pipes or limiters is shown. Figure 1 This is used in the following embodiments. An inert gas, such as nitrogen or vapor, is introduced into the catalyst bed through orifices at the bottom of the reactor. The flowing gas forms a cylindrical path or nozzle through the catalyst bed. The catalyst entrained by the gas flowing through the nozzle is pushed above the surface of the catalyst bed and re-settles in a fountain shape. The catalyst moves downwards in the annular region back to the bottom of the conical bed, thus completing the cycle. The rapid circulation of catalyst and reactants ensures good mixing in the reactor. The fountain is a region of low catalyst density, called the dilute phase, while the annular region is a region of high catalyst density, called the dense phase. In the absence of an inlet pipe, some gas flows around the nozzle and through the annular region.

[0076] Background Example B Figure 2 A schematic diagram of a spouted bed reactor with a drain pipe and a restrictor (top) is shown for use in the following embodiments. Two examples of drain pipes with open and closed sidewalls are shown. Figure 3 In the middle, the gas flowing through the inlet tube creates a negative pressure zone at the bottom of the tube, which draws the catalyst from the annular region and pushes it upwards along the inlet tube. The top-sealed restrictor redirects the catalyst downwards.

[0077] The guide tube directs gas through the nozzle, resulting in less gas passing through the annular region compared to a conventional nozzle-bed reactor. Therefore, the minimum jet velocity is significantly lower with the guide tube present than without it.

[0078] The limiter confines the dilute phase to a smaller volume through more turbulent mixing. The feedstock added to the limiter mixes rapidly with the catalyst. The higher collision frequency between the catalyst and the plastic results in faster heat transfer, melting of the plastic, and distribution of the molten plastic throughout the catalyst.

[0079] Key dimensions of the drainage tube and restrictor arrangement are shown in Figure 4In this context, DO refers to the air inlet opening of the jet bed. DC refers to the diameter of the cylindrical section of the jet bed, and DG refers to the diameter of the restrictor. HG refers to the distance from the top of the drain pipe to the bottom of the restrictor. HG can be approximately 3 to 4 x DO. In some embodiments, HG can be approximately 1.5 to 2.5 DO. In some embodiments, HG should be approximately 2 x DO. In some embodiments, DG can be approximately 3 x DO to 0.7 x DC. In some embodiments, DG can be approximately 4 to 6 x DO, or approximately 5 x DO.

[0080] introduction Catalytic pyrolysis means promoting the initial decomposition of molten plastic into gaseous products on catalyst particles via a catalyst, which differs from passing product gases from thermal pyrolysis through a catalyst bed. This is clearly seen by comparing thermal pyrolysis with catalytic pyrolysis at lower temperatures where thermal pyrolysis is very slow. As Sharratt points out (P. Sharratt et al., Ind. Eng. Chem. Res. 36 (1997) 5118), the thermal cracking of HDPE on siliceous rock and the catalytic pyrolysis on ZSM-5 catalyst can be compared in Table 1 below within the temperature range of 360-430 °C. It can be seen that the thermal cracking at 360 °C is very slow, and only ~6% by weight of gasification is achieved in 60 minutes of reaction. At the same temperature, contact between molten HDPE and the ZSM-5 catalyst results in more than 95% by weight of HDPE gasification. Even at 360 °C, the catalytic pyrolysis of HDPE on ZSM-5 produces significant amounts of C2= to C4= olefins and other medium-range distillate oils such as gasoline (C5-C9). However, in this study, the catalyst was made from pure zeolite pellets and was not deactivated to simulate commercial performance.

[0081] Table 1. Pyrolysis of HDPE in a fluidized bed reactor with ID=10 mm, based on Sharatt's work. Siliceous rocks are pure SiO2 with a pentasil structure and are non-catalytic and inert.

[0082] Driven by the significant difference between catalytic pyrolysis and thermal decomposition at lower temperatures, an isothermal TGA method was developed and is used in this disclosure to screen catalysts with high gasification rates in the temperature range of 360–430 °C. All catalysts used in this invention were formulated and spray-dried into microspheres (APS ~65 μm) for commercial use and hydrothermally deactivated at 1500 °F in 100 v / v% steam for 24 hours to simulate commercial performance.

[0083] In addition to conventional fluidized bed reactors, Aguado (R. Aguado et al.) Ind. Eng. Chem. Res. 41(2002) 4559) has disclosed the use of a sputtered bed reactor for the pyrolysis of plastics, in which HDPE, LDPE, and PP granules (~4 mm) are pyrolyzed on sand particles (~1 mm). The results of the pyrolysis reported by Aguado at 550 °C are summarized in Table 2 below. With a shorter residence time of gaseous products than in a normal fluidized bed, at least 60 wt% of the product is wax, and about 32 wt% or less of light gases (C1-C4) are produced, with very little product (10 wt% or less) in the mid-boiling point (gasoline, C5-C9) range. A comparison between pyrolysis and catalytic pyrolysis in a conical sputtered bed reactor can be made using test data from Elordi (G. Elordi et al., INT. J.CHEM. REACT. ENG., 5 (2007) A72). Test data for HDPE at 500 °C from Aguado and Elordi are summarized in Table 3 below. It can be seen that, compared with thermal cracking, the catalytic pyrolysis of HDPE on a ZSM-5-based catalyst eliminates wax and improves the yield of gasoline, especially light olefins. However, in Aguado and Elordi, the catalysts were 1 mm particles from the extrudate and were not deactivated to simulate the expected performance in a commercial unit with regeneration. The better selectivity for light hydrocarbons on ZSM-5 can be explained by better catalytic pyrolysis and / or better catalytic cracking of wax (gaseous heavy hydrocarbons) at the acidic sites of the zeolite. However, there are no clear indications regarding the role of the ZSM-5 zeolite and how to further improve catalyst performance. Therefore, this disclosure focuses on the use of spray-dried microsphere catalysts (APS = 60-150 µm) in a conical sputtered bed reactor to obtain high yields of light olefins from the catalytic pyrolysis of plastics. The optimized catalyst in this disclosure was tested in a conical sputtered bed reactor at 550 °C to investigate the yield and selectivity improvements of this novel catalyst.

[0084] Table 2.

[0085] Table 3.

[0086] For the use of spray-dried microsphere catalysts (APS = 60-150 µm) in conventional fluidized bed and / or conical spouted bed reactors for plastic pyrolysis, catalysts with higher gasification activity are critical and highly desirable, in addition to improving reactor structure with inlet pipes and fountain confiners. This is because they can reduce the thickness of the molten plastic coated on the catalyst particles, thus reducing the chance of defluidization and the size of reactors for commercial applications. Therefore, one of the focuses of this disclosure is how to improve catalysts to achieve higher activity for the gasification of plastics, especially polyolefins such as polypropylene and polyethylene, which have high volume in plastic waste for sustainable recycling.

[0087] As cited in previous papers, ZSM-5 zeolite is considered a good candidate for catalytic pyrolysis of plastics. However, two issues need to be addressed for it to be used as a practical catalyst in the commercial pyrolysis of plastics: (1) hydrothermal stability. It is well known in industry that unstabilized ZSM-5 loses its acidity and porosity due to hydrothermal deactivation, and thus loses its catalytic activity and selectivity. Therefore, in this disclosure, P-stabilized ZSM-5 is chosen based on its proven stability; (2) the micropore size of ZSM-5 zeolite, as described by Degnan, is only ~5.5 Å, since the molecular size of molten plastics is much larger than the micropore size of ZSM-5 zeolite (TF Degnan et al.). Studies in Surface Science and Catalysis(Vol. 76 (1993) 499), the vaporization of molten plastic may only occur at acidic sites on the outer surface of zeolite crystals, and only when the zeolite particles are in a porous structure and accessible to the molecules of molten plastic. To increase pre-cracking sites for molten plastic molecules in addition to the acidic sites of ZSM-5, a mesoporous active matrix is ​​introduced and optimized in this invention. Similar to FCC catalysts, the typical components of a pyrolysis catalyst are zeolite and a matrix material, which may include binders, clay, high surface area Al2O3, SiO2, and / or SiO2-Al2O3. Pre-cracking of large molten plastic molecules can occur at acidic sites in intentionally added mesoporous active matrix materials such as clay, Al2O3, and / or SiO2-AlO3. This is a very successful method used in the past in the formulation of Y zeolite-based FCC catalysts, where high surface area matrix materials can be used to improve bottom oil cracking (see U.S. Patent No. 8,642,499 to W.-C. Cheng et al.). However, the use of mesoporous active matrices is rarely seen for ZSM-5-based catalysts, as they are typically used to treat smaller molecules in the C5 to C10 range. Surprisingly, a significant increase in the catalytic pyrolysis rate of HPP and LLDPE was observed when a mesoporous active matrix (such as kaolin and / or soluble mesoporous Al2O3) was included in the same catalyst particles as p-stabilized ZSM-5. This demonstrates a synergistic effect between clay, activated Al2O3, and zeolite to achieve better gasification activity. The catalyst with a mesoporous active matrix showed a 5- to 10-fold increase in the gasification rate of HPP and LLDPE at 400 °C compared to catalysts without a mesoporous active matrix, although this approach was less effective in the pyrolysis of HDPE. Further investigation into the effect of mesoporous surface area revealed that the gasification rates of LLDPE, HPP, and HDPE increased with increasing Al2O3 content ranging from 12 wt% to 40 wt%. Furthermore, selectivity tests in a conical sputtered bed reactor appear to indicate that the yield of light olefins at 550 °C significantly increases with increasing ZSM-5 content during the catalytic pyrolysis of HPP and LLDPE. These results suggest that ZSM-5 content is more important for the catalytic reaction after gasification.

[0088] To maximize the yield of light olefins, particularly propylene and ethylene, in the same reactor used for the catalytic pyrolysis of plastics, the catalyst needs not only to have high activity in converting molten plastics into gaseous hydrocarbons, but also high activity derived from phosphorus-stabilized ZSM-5, which exhibits good hydrothermal stability and excellent selectivity in converting gasoline-range olefins into light olefins such as butene, propylene, and ethylene (A. Corma et al.). J of CatalysisVolume 237 (2006) 267). The disclosed P-ZSM5 catalyst successfully combines a high mesoporous active matrix content with a P-ZSM5 loading of up to 50-60 wt% without sacrificing the activity from either component. Pyrolysis tests of HPP, LLDPE, and HDPE on the high P-ZSM5 loading catalyst at 550 °C in a small conical sputtered bed reactor showed a propylene yield of ~27-28 wt%, which is 2-8 wt% higher than the baseline. The total light olefin yield is also the highest in our invention, and in the range of 52-55 wt% on HPP, LLDPE, and HDPE, which is 5-15 wt% higher than the baseline.

[0089] Example 1 (Basic, Cat B) Cat B is a commercially available phosphorus-stabilized ZSM-5 additive from WR Grace. It contains 55% by weight ZSM-5, with the remainder consisting of alumina sol binder, boehmite alumina, phosphoric acid, and Natka clay. Prior to any performance testing, the catalyst was deactivated by steam in a fluidized bed reactor at 816°C in a 100% steam atmosphere for 24 hours. The properties of the fresh and steam-treated catalysts are shown in Table 4 below.

[0090] Example 2 (Comparative catalyst C-1) Comparative catalyst C-1 was prepared using 40% acid-gelled alumina and 60% by weight Natka clay. The slurry containing these two raw materials was milled in a Netzsch mill and then spray-dried in a Bowen spray dryer. The spray-dried product was calcined in a muffle furnace at 600°C for 1 hour. Prior to any performance testing, the catalyst was steam-deactivated in a fluidized bed reactor at 816°C in a 100% steam atmosphere for 24 hours. The properties of the fresh and steam-treated catalysts are shown in Table 4 below.

[0091] Example 3 (Invention, D-1) Catalyst D-1 was prepared as follows, containing 25 wt% CATB, 40 wt% acid-gelled alumina, 3 wt% alumina sol, and 32 wt% Natka clay. CATB dry powder was slurried with water and ground before being used as a raw material. The ground CATB slurry was then mixed with acid-gelled alumina, alumina sol, and Natka clay. The resulting mixture was ground in a Netzsch mill and spray-dried in a Bowen spray dryer. The spray-dried product was calcined in a muffle furnace at 600°C for 1 hour. Before any performance testing, the catalyst was steam-deactivated in a fluidized bed reactor at 816°C in a 100% steam atmosphere for 24 hours. The properties of the steam-treated catalyst are shown in Table 4 below. Total surface area (TSA) was measured using the standard nitrogen BET technique. Each sample was measured to determine its TSA. The percentage of ZSM-5 in the catalyst formulation was multiplied by a coefficient of 3.4 for steam-deactivated samples (m² per 1% ZSM-5). 2 The coefficient for the fresh sample was 3.2 (m / g ZSA) and 3.2 (m per 1% ZSM-5). 2 The zeolite surface area (ZSA) of each sample was determined using a nitrogen / argon adsorption analysis (TIA / g ZSA). This coefficient was determined based on nitrogen / argon adsorption analysis data reported by Shen et al. (Microporous and Mesoporous Materials, Vol. 344, 2022, Article 112210). The matrix surface area (MSA) was then calculated by the difference between TSA and ZSA. Pore volume (PV) in the range of 40–600 Å was measured using a Micromeritics AutoPore V mercury pore size analyzer conforming to ASTM Test Method D4284.

[0092] Table 4 below shows the properties of cat B, C1, and D1 after steam treatment.

[0093] Table 4.

[0094] Example 4: TGA testing of B, C1, and D1 at 400°C Laboratory tests of the vaporization rate of catalytic pyrolysis were conducted on a computerized thermobalance (TA Q500). Prior to testing, the thermobalance was preloaded with a well-mixed mixture of 3–9 mg catalyst and 20–30 mg plastic powder (<0.5 mm). The test was initiated with an inert atmosphere introduced using 110 sccm N2 controlled by a mass flow controller. This flow rate was maintained constant throughout the experiment. Simultaneously, the temperature was increased to 250 °C at a heating rate of 50 °C / min. This temperature was then maintained at 250 °C for 15 minutes to obtain stable balance readings unaffected by moisture, while the plastic sample was completely melted. The temperature was then increased to 400 °C at a rate of 50 °C / min and maintained at 400 °C for 2 hours as the isothermal pyrolysis step of the plastic. The weight loss rate was then calculated using the following equation. After two hours of pyrolysis, the carrier gas was switched to 100 sccm air, and the temperature was increased to 600 °C at 10 °C / min, subsequently maintained at 600 °C for 1 hour to complete catalyst regeneration (coke combustion). The furnace is slowly cooled to room temperature, during which the sample is mixed with another plastic sample, and the above procedure is repeated as a second test. The reported result is the average of the two tests. Typically, the difference between the results of the two tests is within 10%.

[0095] The average rate at which 90% conversion is achieved (g plastic / g catalyst min) = (1 / time to achieve 90% conversion) (Weight of plastic / weight of catalyst). Three commercially available plastic samples were used in the TGA experiments. These included samples of HPP, HDPE, and LLDPE. The samples were originally ~4 mm granules, which were then cryogenically ground into powder (<0.5 mm) prior to the TGA tests. Details of the three plastic powders are listed in Table 5 below.

[0096] Table 5

[0097] Prior to the activity tests, fresh samples of catalysts B, C-1, and D-1 were steam-deactivated for 24 hours at 816 °C in a 100% steam atmosphere in a fluidized bed reactor to simulate the performance of commercial equilibrium catalysts. The test results are listed in Table 6 below.

[0098] Table 6

[0099] The results show that the mesoporous active matrix (C-1) itself is highly active, exceeding the activity of the P-stabilized ZSM-5 catalyst (CAT B) without a matrix. Further improvement in the gasification rate was achieved by combining the mesoporous active matrix with the P-stabilized ZSM-5 catalyst according to the catalyst disclosed herein (D-1), demonstrating a synergistic effect between the mesoporous active matrix and the zeolite component. Compared to the ZSM-5 catalyst without a mesoporous active matrix, the gasification rate of D-1 was increased by more than ~10 times in the pyrolysis of HPP and LLDPE, and by ~2 times for HDPE.

[0100] Example 5 (Invention, D-2). Catalyst D-2 was prepared as follows, containing 25 wt% CATB, 0 wt% acid-gel sol alumina, 20 wt% alumina sol, and 55 wt% Natka clay. The dry CATB powder was slurried with water and ground before being used as a raw material. The ground CATB slurry was then mixed with the alumina sol and Natka clay. The resulting mixture was ground in a Netzsch mill and spray-dried in a Bowen spray dryer. The spray-dried product was calcined in a muffle furnace at 600°C for 1 hour. Prior to any performance testing, the catalyst was steam-deactivated in a fluidized bed reactor at 816°C in a 100% steam atmosphere for 24 hours. The properties of the fresh and steam-treated catalysts are shown in Table 7 below.

[0101] Example 6 (Invention, D-3) Catalyst D-3 was prepared as follows, containing 25 wt% CATB, 12 wt% acid-gelled alumina, 8 wt% alumina sol, and 55 wt% Natka clay. The dry CATB powder was slurried with water and milled before being used as a raw material. The milled CATB slurry was then mixed with acid-gelled alumina, alumina sol, and Natka clay. The resulting mixture was milled in a Netzsch mill and spray-dried in a Bowen spray dryer. The spray-dried product was calcined in a muffle furnace at 400°C for 1 hour, followed by washing with water and ammonia solution. Prior to any performance testing, the catalyst was steam-deactivated in a fluidized bed reactor at 816°C in a 100% steam atmosphere for 24 hours. The properties of the fresh and steam-treated catalysts are shown in Table 7 below.

[0102] Example 7 (Invention, D-4) Catalyst D-4 was prepared as follows, containing 25 wt% CATB, 26 wt% acid-gelled alumina, 8 wt% alumina sol, and 41 wt% Natka clay. The dry CATB powder was slurried with water and milled before being used as a raw material. The milled CATB slurry was then mixed with acid-gelled alumina, alumina sol, and Natka clay. The resulting mixture was milled in a Netzsch mill and spray-dried in a Bowen spray dryer. The spray-dried product was calcined in a muffle furnace at 400°C for 1 hour, followed by washing with water and ammonia solution. Prior to any performance testing, the catalyst was steam-deactivated in a fluidized bed reactor at 816°C in a 100% steam atmosphere for 24 hours. The properties of the steam-treated catalyst are shown in Table 7 below.

[0103] Table 7

[0104] Example 8: TGA testing of D-2, D-3, and D-4 at 400°C Prior to activity testing, fresh samples of catalysts D-2, D-3, and D-4 were steam-deactivated for 24 hours at 816°C in a 100% steam atmosphere in a fluidized bed reactor to simulate the performance of commercial equilibrium catalysts. The steam-treated samples were tested according to the test procedure in Example 5 and compared with D-1. The TGA test results are listed in the table below.

[0105] Table 8

[0106] The results show that the matrix activity increases with the increase of colloidal Al2O3 content, which, in addition to its acidity, also helps to introduce mesoporous structure and MSA into the catalyst.

[0107] Example 9 (Invention, D-5) Catalyst D-5 was prepared as follows, containing 35 wt% CATB, 40 wt% acid-gelled alumina, 5 wt% alumina sol, and 20 wt% Natka clay. The dry CATB powder was slurried with water and ground before being used as a raw material. The ground CATB slurry was then mixed with acid-gelled alumina, alumina sol, and Natka clay. The resulting mixture was ground in a Netzsch mill and spray-dried in a Bowen spray dryer. The spray-dried product was calcined in a muffle furnace at 400°C for 1 hour. Prior to any performance testing, the catalyst was steam-deactivated in a fluidized bed reactor at 816°C in a 100% steam atmosphere for 24 hours. The properties of the fresh and steam-treated catalysts are shown in Table 9 below.

[0108] Example 10 (Invention, D-6) Catalyst D-6, containing 53 wt% CATB, 40 wt% acid-gelled alumina, and 7 wt% alumina sol, was prepared as follows. The dry CATB powder was slurried with water and ground before being used as a raw material. The ground CATB slurry was then mixed with the acid-gelled alumina and alumina sol. The resulting mixture was ground in a Netzsch mill and spray-dried in a Bowen spray dryer. The spray-dried product was calcined in a muffle furnace at 400°C for 1 hour. Prior to any performance testing, the catalyst was steam-deactivated in a fluidized bed reactor at 816°C in a 100% steam atmosphere for 24 hours. The properties of the steam-treated catalyst are shown in Table 9 below.

[0109] Table 9

[0110] Example 11: TGA testing of D-5 and D-6 at 400°C Prior to activity testing, fresh samples of catalysts D-5 and D-6 were steam-deactivated in a fluidized bed reactor at 816°C in a 100% steam atmosphere for 24 hours to simulate the performance of commercial equilibrium catalysts. The steam-treated sample was tested according to the test procedure in Example 5 and compared with D-1. The TGA test results are listed in Table 10 below.

[0111] Table 10

[0112] The results show that the gasification rate did not vary significantly when the loading of CATB (containing P-stabilized ZSM-5) varied from 25% to 53% by weight. However, the ZSM-5 content remains crucial for product selectivity, which needs to be verified under specific reactor conditions.

[0113] Example 12 Selectivity test of B, D-5 and D-6 at 550°C Prior to the activity tests, fresh samples of catalysts D-5 and D-6 were steam-deactivated for 24 hours at 816°C in a 100% steam atmosphere in a fluidized bed reactor to simulate the performance of commercial equilibrium catalysts. In the selectivity tests, 135 g of catalyst was loaded into a spouted bed reactor equipped with a guide tube and limiter as described herein and heated to 550°C, using nitrogen at 5.2 NL / min as the jet gas. Granules of plastic samples (HPP, LLDPE, and HDPE, and identical to those in Example 5) were loaded into the reactor at 1 g / min. The test reached steady-state operation within 30 minutes, and the product distribution during steady-state operation was recorded. The test results for D-5 and D-6 are compared with B in Tables 11, 12, and 13 below.

[0114] Table 11. Selectivity test results for HPP at 550℃

[0115] The pyrolysis results of HPP at 550 °C show that the propylene and total C2-C5 olefin yields from this catalyst prepared according to the present disclosure are significantly higher than those from conventional ZSM-5-based catalyst B, primarily due to their lower selectivity for saturated products. Although the gasoline fraction yield is higher, it provides very high levels of gasoline olefins, which are more readily cracked into lighter C2-C4 olefins using additional gasoline-to-olefins technologies. The propylene yield of the catalyst according to the present disclosure increases with the loading of the ZSM-5 catalyst, a clear indication of the role of ZSM-5 and pointing towards further improvements in C3= yields.

[0116] Table 12. Selectivity test results for LLDPE at 550℃

[0117] The pyrolysis results of LLDPE at 550 °C are very similar to those from HPP, where the catalyst prepared according to this disclosure has much higher selectivity for light olefins.

[0118] Table 13

[0119] For the catalyst according to this disclosure, the pyrolysis results of HDPE at 550°C are similar to those of HPP and LLDPE in terms of better C3 and gasoline olefin content. However, a slightly different trend was observed regarding propylene yield. A possible explanation is that the increase in gasification rate during HDPE pyrolysis benefits least from this catalyst (see results in Example 5), and therefore, the thermal gasification of HDPE remains significant, while the addition of the active matrix dilutes the ZSM-5 content used for other gas-phase reactions after gasification.

[0120] Example 13 (Invention, D-7) Catalyst D-7 was prepared as follows, containing 53 wt% phosphorus-prestabilized ZSM-5 (p-ZSM-5), 40 wt% acid-gelled alumina, 7 wt% alumina sol, and 0 wt% Natka clay. The ZSM-5 slurry was mixed with phosphoric acid and ground before being used as a feedstock, then spray-dried and calcined at 600°C for 1 hour. Spray-dried P-ZSM-5 containing 9.4% P₂O₅ was then mixed with acid-gelled alumina and alumina sol. The resulting mixture was ground in a Netzsch mill and spray-dried in a Bowen spray dryer. The spray-dried product was calcined in a muffle furnace at 400°C for 1 hour, followed by washing with water and ammonia solution. Before any performance testing, the catalyst was steam-deactivated in a fluidized bed reactor at 816°C in a 100% steam atmosphere for 24 hours. The properties of the fresh and steam-treated catalysts are shown in Table 14 below.

[0121] Example 14 (Invention, D-8) Catalyst D-8 was prepared as follows, containing 53 wt% phosphorus-prestabilized ZSM-5 (p-ZSM-5), 40 wt% acid-gelled alumina, 7 wt% alumina sol, and 0 wt% Natka clay. The ZSM-5 slurry was mixed with phosphoric acid and ground before being used as a feedstock, then spray-dried and calcined at 600°C for 1 hour. Spray-dried P-ZSM-5 containing 11.6% P₂O₅ was then mixed with acid-gelled alumina and alumina sol. The resulting mixture was ground in a Netzsch mill and spray-dried in a Bowen spray dryer. The spray-dried product was calcined in a muffle furnace at 400°C for 1 hour, followed by washing with water and ammonia solution. Before any performance testing, the catalyst was steam-deactivated in a fluidized bed reactor at 816°C in a 100% steam atmosphere for 24 hours. The properties of the fresh and steam-treated catalysts are shown in Table 14 below.

[0122] Example 15 (Invention, D-9) Catalyst D-9 was prepared as follows, containing 53 wt% phosphorus-prestabilized ZSM-5 (p-ZSM-5), 40 wt% acid-gelled alumina, 7 wt% alumina sol, and 0 wt% Natka clay. The ZSM-5 slurry was mixed with phosphoric acid and ground before being used as a feedstock, then spray-dried and calcined at 600°C for 1 hour. Spray-dried p-ZSM-5 containing 14.1% P₂O₅ was then mixed with acid-gelled alumina and alumina sol. The resulting mixture was ground in a Netzsch mill and spray-dried in a Bowen spray dryer. The spray-dried product was calcined in a muffle furnace at 400°C for 1 hour, followed by washing with water and ammonia solution. Before any performance testing, the catalyst was steam-deactivated in a fluidized bed reactor at 816°C in a 100% steam atmosphere for 24 hours. The properties of the fresh and steam-treated catalysts are shown in Table 14 below.

[0123] Table 14 Properties of catalysts D-7, D-8 and D-9

[0124] Example 15: TGA testing of D-7, D-8, and D-9 at 400°C Prior to activity testing, fresh samples of catalysts D-7, D-8, and D-9 were steam-deactivated for 24 hours at 816°C in a 100% steam atmosphere in a fluidized bed reactor to simulate the expected performance of commercial equilibrium catalysts. The steam-treated samples were tested according to the test procedure in Example 5 and compared with the base catalyst (B) and catalyst D-6. The TGA test results are listed in Table 15 below.

[0125] Table 15 TGA test results for catalysts B, D-6, D-7, D-8, and D-9

[0126] The results showed that by using phosphorus-prestabilized ZSM-5 instead of Cat B, the combination of the mesoporous active matrix and p-ZSM-5 also produced catalysts with significantly higher activity for plastic gasification than conventional ZSM-5 catalyst (B). Furthermore, the gasification activities of catalysts D-7, D-8, and D-9 in the pyrolysis of HPP, LLDPE, and HDPE at 400 °C were similar to those of D-6. With increasing P2O5 content from D-7 to D-9, the gasification activity decreased only slightly, possibly due to the increased chance of matrix poisoning caused by phosphorus migration.

[0127] Example 16 Selectivity test of D-7, D-8 and D-9 at 550°C Prior to activity testing, fresh samples of catalysts D-7, D-8, and D-9 were steam-deactivated for 24 hours at 816°C in a 100% steam atmosphere in a fluidized bed reactor to simulate the performance of commercial equilibrium catalysts. In selectivity testing, each catalyst was tested in a sputtered bed reactor under the conditions described in Example 13. This test reached steady-state operation within 30 minutes, and the product distribution at steady-state operation was recorded. The test results for D-7, D-8, and D-9 are compared with those for catalysts B and D-6 in Tables 16, 17, and 18 below.

[0128] Table 16. Selectivity test results for HPP at 550℃

[0129] The pyrolysis results of HPP at 550 °C clearly show that the yields of propylene and total C2-C5 olefins from catalysts D-7, D-8, and D-9 are not only higher than those from the base catalyst B, but also higher than those from catalyst D-6, mainly due to the higher P-ZSM-5 input. With the aid of the mesoporous active matrix, gasoline yields are higher with a higher gasoline olefin fraction in the case of D-6. At a P-ZSM-5 loading of 53 wt%, D-7, D-8, and D-9 are able to further convert gasoline olefins into lighter olefins. Propylene yield reaches its maximum with catalyst D-8, where the P2O5 loading achieves an optimal balance between the good hydrothermal stability of P-ZSM-5 and less P migration in terms of matrix poisoning.

[0130] Table 17. Selectivity test results for LLDPE at 550℃

[0131] The pyrolysis results of LLDPE at 550 °C on catalysts D-7, D-8, and D-9 are very similar to those from HPP, where the yields of light olefins are much higher for the catalysts prepared according to this disclosure. Propylene yields are maximized with catalyst D-9, which has the lowest gasoline yield, although the gasoline aromatics yields on catalyst D-9 are still significantly lower than those from base catalyst B.

[0132] Table 18. Selectivity test results for HDPE at 550℃

[0133] Similar to D-6, HDPE pyrolysis at 550°C on catalysts D-7, D-8, and D-9 yielded better C3 and gasoline olefin content than the base catalyst B. As the P-ZSM-5 loading increased from D-6 to D-7, 8, and 9, propylene yield returned to ≥26 wt%, exceeding that of catalyst B. With catalyst D-8, the propylene yield reached a maximum of 27.8 wt%, 2.3 wt%, higher than catalyst B. Among the increases in light olefin yields from LLDPE and HPP, the increase from HDPE pyrolysis was the smallest. This can also be explained by the minimal increase in catalytic gasification rate during HDPE pyrolysis.

[0134] Although certain embodiments have been illustrated and described, it should be understood that variations and modifications can be made to them in accordance with common art without departing from the art as defined in its broader aspects as in the following claims.

[0135] The embodiments exemplified herein can be suitably implemented in the absence of any one or more elements or limitations not specifically disclosed herein. Therefore, terms such as “comprising,” “including,” and “containing” should be interpreted broadly and not restrictively. Furthermore, the terms and expressions used herein have been used as descriptive rather than restrictive terms, and it is not intended to exclude any equivalents of the features shown and described or portions thereof, but rather to recognize that various modifications may be made within the scope of the claimed technology. Additionally, the phrase “consistently of…” is understood to include those specifically listed elements and those additional elements that do not materially affect the basic and novel features of the claimed technology. The phrase “consisting of…” excludes any unspecified elements.

[0136] This disclosure is not limited to the specific embodiments described in this application. As will be apparent to those skilled in the art, many modifications and variations can be made without departing from its spirit and scope. Functionally equivalent methods and compositions within the scope of this disclosure, other than those listed herein, will be apparent to those skilled in the art from the foregoing description. Such modifications and variations are intended to fall within the scope of the appended claims. This disclosure is limited only by the terms of the appended claims and the full scope of their equivalents. It should be understood that this disclosure is not limited to specific methods, reagents, compounds, or compositions, which are of course variable. It should also be understood that the terminology used herein is for the purpose of describing specific embodiments only and is not intended to constitute limitation.

[0137] Furthermore, when features or aspects of this disclosure are described in terms of the Markush group, those skilled in the art will recognize that this disclosure is also described in terms of any single member or subgroup of members of that Markush group.

[0138] As those skilled in the art will understand, for any and all purposes, particularly in providing a written description, all scopes disclosed herein also encompass any and all possible subscopes and combinations thereof. Any enumerated scope can be readily considered sufficiently descriptive and allows the same scope to be divided into at least two, three, four, five, ten, etc., parts. As a non-limiting example, each scope discussed herein can be readily divided into a lower third, a middle third, and an upper third, etc. As those skilled in the art will also understand, all words such as “at most,” “at least,” “greater than,” and “less than” include the enumerated numerical values ​​and refer to a scope that can subsequently be divided into subscopes as described above. Finally, as those skilled in the art will understand, a scope includes individual members.

[0139] All publications, patent applications, granted patents, and other documents mentioned in this specification are incorporated herein by reference, as if each publication, patent application, granted patent, or other document were expressly and individually indicated to be incorporated herein by reference in its entirety. Definitions contained in the text incorporated herein by reference are excluded in the event of any conflict between them and the definitions in this disclosure.

[0140] Other embodiments are set forth in the following claims.

Claims

1. A catalyst composition comprising: Mesoporous active matrix; and Phosphorus-stabilized ZSM-5.

2. The catalyst composition according to claim 1, wherein the mesoporous active matrix comprises one or more of kaolin and colloidal alumina.

3. The catalyst composition according to claim 1 or 2, wherein, based on the total weight of the catalyst composition, the catalyst composition comprises more than about 30% of one or more of kaolin and colloidal alumina.

4. The catalyst composition according to any one of claims 1-3, wherein the catalyst composition comprises more than about 10% colloidal alumina based on the total weight of the catalyst composition.

5. The catalyst composition according to claim 4, wherein, based on the total weight of the catalyst composition, the catalyst composition contains more than about 30% colloidal alumina.

6. The catalyst composition according to any one of claims 1-5, wherein the catalyst composition comprises about 10% to about 70% colloidal alumina based on the total weight of the catalyst composition.

7. The catalyst composition according to any one of claims 1-6, wherein the mesoporous active matrix comprises pores with a pore size of about 20 Å to about 600 Å, or about 40 Å to about 600 Å.

8. The catalyst composition according to any one of claims 1-6, wherein the mesoporous active matrix comprises pores with a pore size greater than about 600 Å.

9. The catalyst composition according to any one of claims 1-7, wherein the mesoporous active matrix has a density of approximately 50 μm before deactivation. 2 / g to approximately 250 m 2 / g of surface area.

10. The catalyst composition according to claim 9, wherein the mesoporous active matrix has a density of approximately 60 μm before deactivation. 2 / g to approximately 200 m 2 / g, approximately 80 m 2 / g to approximately 150 m 2 / g, or approximately 90 m 2 / g to approximately 120 m 2 / g of surface area.

11. The catalyst composition according to any one of claims 1-10, wherein the mesoporous active matrix has a pore volume greater than about 0.01 cc / g.

12. The catalyst composition of claim 11, wherein the mesoporous active matrix has a pore volume of about 0.1 cc / g to about 0.4 cc / g.

13. The catalyst composition according to any one of claims 1-12, wherein, based on the total weight of the catalyst composition, the catalyst composition comprises more than about 5% w / w of phosphorus-stabilized ZSM-5.

14. The catalyst composition of claim 13, wherein, based on the total weight of the catalyst composition, the catalyst composition comprises about 5% to about 70% of phosphorus-stabilized ZSM-5.

15. The catalyst composition according to any one of claims 1-14, wherein the phosphorus-stabilized ZSM-5 further comprises one or more metals selected from iron, copper, zinc, nickel, titanium, vanadium, chromium, manganese, cobalt, gallium and boron.

16. The catalyst composition according to any one of claims 1-15, wherein the phosphorus-stabilized ZSM-5 has a crystallite size of about 0.05 micrometers to about 2 micrometers.

17. The catalyst composition according to any one of claims 1-16, wherein the catalyst composition comprises from about 0.5% w / w to about 15% w / w P2O5 based on the total weight of the composition.

18. The catalyst composition according to any one of claims 1-17, wherein the phosphorus-stabilized ZSM-5 and the mesoporous active matrix are separated particles in the catalyst composition.

19. A method for preparing a catalyst composition, the method comprising: (a) Provide an aqueous slurry A containing solid particles of phosphorus-stabilized pentasil zeolite; (b) Slurry A is combined with colloidal alumina, kaolin and alumina sol to provide slurry B; (c) Spray-dry slurry B to form catalyst particles; and (d) Calcining the spray-dried catalyst particles at a temperature and time sufficient to remove volatiles and recover the catalyst composition; in: The catalyst composition comprises a mesoporous active matrix and phosphorus-stabilized pentasil zeolite.

20. The method of claim 19, wherein the method further comprises washing the calcined catalyst particles with water and an ammonia solution with a pH of about 3 to about 7.

5.

21. The method according to claim 19 or 20, wherein the phosphorus-stabilized pentasil zeolite is phosphorus-stabilized ZSM-5.

22. The method of claim 21, wherein the phosphorus-stabilized ZSM-5 is prepared by any stabilization method, such as impregnation with a suitable phosphorus compound such as H3PO4, (NH4)H2PO4, (NH4)2HPO4 and (NH4)3PO4 by slurry addition, spray drying and optionally grinding ZSM-5 particles; drying at a temperature of about 120°C; and calcining at about 600°C for about 1 hour.

23. The method of claim 21 or 22, wherein the phosphorus-stabilized ZSM-5 is derived from commercially available ZSM-5.

24. The method according to any one of claims 21-23, wherein the aqueous slurry A comprises solid particles of phosphorus-stabilized ZSM-5 in an amount sufficient to provide a catalyst composition comprising more than about 5% w / w of phosphorus-stabilized ZSM-5 based on the total weight of the catalyst composition.

25. The method according to any one of claims 19-24, wherein the aqueous slurry B comprises soluble alumina in an amount sufficient to provide a catalyst composition comprising more than about 10% w / w of soluble alumina based on the total weight of the catalyst composition.

26. The method according to any one of claims 19-25, wherein the alumina sol exists in the slurry in an amount sufficient to provide binding for a catalyst comprising about 5% to about 50% alumina based on the total weight of the catalyst composition.

27. The method according to any one of claims 19-26, wherein spray drying provides catalyst particles having a particle size of about 20 micrometers to about 200 micrometers.

28. A method for producing at least one or more of olefins and aromatic compounds from plastic raw materials, the method comprising: In a fluidized bed or conical sputtered bed reactor, the plastic feedstock and the catalyst composition according to any one of claims 1-16 are contacted for a sufficient time at a temperature of about 400°C to about 700°C and in an oxygen-deficient environment to allow at least a portion of the plastic feedstock to be converted into a product stream comprising olefins, aromatic compounds, or a mixture of olefins and aromatic compounds.

29. The method of claim 28, wherein the contact between the plastic raw material and the catalyst composition is carried out at a temperature of about 500°C to about 600°C.

30. The method according to claim 28 or 29, wherein the plastic raw material comprises at least one of polyethylene, polypropylene, polystyrene, polyethylene terephthalate (PET), polyvinyl chloride (PVC), polyamide, polycarbonate, polyurethane, polyester, natural and synthetic rubber, tires, filled polymers, composite materials, plastic alloys, and plastics dissolved in a solvent.

31. The method of claim 30, wherein the plastic raw material comprises polyethylene, such as LLDPE and HDPE.

32. The method of claim 30, wherein the plastic raw material comprises polypropylene, such as HPP.

33. The method according to any one of claims 28-32, wherein the product stream comprises olefins, including ethylene, propylene, butene, or any two or more of these.

34. The method of claim 33, wherein the product stream comprises about 15% by weight to about 60% by weight of olefins, such as ethylene, propylene and butene.

35. The method according to any one of claims 28-30, wherein the product stream comprises an aromatic compound, including benzene, toluene, xylene, or a mixture of any two or more thereof.

36. The method according to any one of claims 28-35, wherein the method uses a conical spouted bed reactor comprising a drain tube and a limiter.

37. The method according to any one of claims 28-35, wherein the method uses a fluidized bed reactor.

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