Circular economy of waste plastics to polyethylene via petroleum refining with filtration and metal oxide treatment of pyrolysis oil

Abstract

In one embodiment, a continuous process for converting waste plastics containing polyethylene and / or polypropylene into polyethylene for recycling for polymerization is provided. The process includes selecting waste plastics containing polyethylene, polypropylene, or a mixture thereof, and passing the waste plastic through a pyrolysis reactor to thermally decompose at least a portion of the polyolefin waste and produce a pyrolysis effluent. The pyrolysis effluent is separated into off-gas, pyrolysis oil (including naphtha, diesel, and heavy fractions), and char. The pyrolysis oil, or at least a fraction thereof, is passed through a filtration / metal oxide treatment, and the treated product is passed through a refinery FCC unit. A liquefied petroleum gas C3 olefin / paraffin mixture fraction and a C4 olefin / paraffin mixture fraction are recovered from the FCC unit. The liquefied petroleum gas C3 olefin / paraffin mixture fraction is passed through a steam cracker for ethylene production.

Description

[Technical field]

[0001] (background) The world has witnessed a very rapid growth in plastic production. According to PlasticsEurope Market Research Group, global plastic production was 335 million tonnes in 2016, 348 million tonnes in 2017, and 359 million tonnes in 2018. According to McKinsey & Company, the global volume of plastic waste was estimated at approximately 260 million tonnes per year in 2016 and is projected to reach 460 million tonnes per year by 2030 if the current trajectory continues. [Background technology]

[0002] Single-use plastic waste is becoming an increasingly significant environmental issue. At present, there appear to be few options for recycling polyethylene and polypropylene waste plastics into value-added chemical and fuel products. Currently, only small amounts of polyethylene and polypropylene are recycled via chemical recycling, and this recycled and cleaned polymer pellets are pyrolyzed in pyrolysis units to produce fuels (naphtha, diesel), steam cracker feedstock, or slack wax.

[0003] Processes for converting waste plastics into hydrocarbon lubricants are known. For example, U.S. Pat. No. 3,845,157 discloses the cracking of waste or virgin polyolefins to form gaseous products such as ethylene / olefin copolymers, which are further processed to produce synthetic hydrocarbon lubricants. U.S. Pat. No. 4,642,401 discloses the heating of pulverized polyolefin waste at temperatures between 150 and 500° C. and pressures between 20 and 300 bar (2 to 30 MPa) to produce liquid hydrocarbons. U.S. Pat. No. 5,849,964 discloses a process for depolymerizing waste plastic materials into volatile and liquid phases. The volatile phase is separated into a gas phase and a condensate. The liquid, condensate and gas phases are refined into liquid fuel components using standard refining techniques. U.S. Pat. No. 6,143,940 discloses a procedure for converting waste plastics into heavy wax compositions. U.S. Pat. No. 6,150,577 discloses a process for converting waste plastics into lubricating oils. EP 0 620 264 A1 discloses a process for producing lubricants from waste or virgin polyolefins by thermally cracking the waste in a fluidized bed to form a waxy product, optionally using hydrotreating, followed by catalytic isomerization and fractionation to recover the lubricants.

[0004] Other documents relating to processes for converting waste plastics into lubricants include U.S. Patent Nos. 6,288,296, 6,774,272, 6,822,126, 7,834,226, 8,088,961, 8,404,912 and 8,696,994, and U.S. Patent Application Publication Nos. 2019 / 0161683, 2016 / 0362609 and 2016 / 0264885. The aforementioned patent documents are incorporated herein by reference in their entirety.

[0005] Current methods of chemical recycling via pyrolysis are not capable of making a significant impact on the plastics industry. Current pyrolysis operations produce poor quality fuel components (naphtha and diesel range products) but in small enough quantities that these products can be blended into the fuel supply. However, to recycle the very large quantities of waste polyethylene and waste polypropylene required to address environmental concerns, such simple blending cannot continue. The raw products from pyrolysis units are too poor quality to be blended in large quantities (e.g., 5-20 vol.% blends) into transportation fuels.

[0006] More robust processes are needed to industrially recycle single-use plastics on a large scale and reduce their environmental impact. These improved processes should establish a "circular economy" for waste polyethylene and polypropylene plastics, effectively recycling post-consumer waste plastics as starting material for polymers and high-value by-products. Summary of the Invention

[0007] Provided is a continuous process for converting waste plastics to recycle for polyethylene polymerization. The process includes selecting waste plastics containing polyethylene and / or polypropylene. These waste plastics are then passed through a pyrolysis reactor to thermally crack at least a portion of the polyolefin waste and produce a pyrolyzed effluent. The pyrolyzed effluent is separated into off-gas, pyrolysis oil (including naphtha, diesel, and heavy fractions), and char. In addition to pyrolysis oil, pyrolysis wax can also be produced.

[0008] The integration of this process into oil refinery is an important aspect of the process, and can achieve a circular economy with single-use waste plastics such as polyethylene or polypropylene. Thus, pyrolysis oil (e.g., the entire liquid fraction from the pyrolysis unit) can be passed to a refinery FCC unit from which liquid petroleum olefin streams can be recovered. These liquid petroleum olefin streams can be passed directly to a steam cracker for ethylene production. This ethylene is then passed to a polymerization unit for polyethylene production.

[0009] Another important aspect of the process is upgrading the liquid pyrolysis products before the stream is integrated with the refining unit. Pyrolysis oil and wax waste plastics contain multiple contaminants and cannot be fed in large quantities to refining units such as FCC units because these contaminants would deactivate the refining catalysts, cause clogging of the units, or cause corrosion in the processing units, which are generally made of carbon steel. The use of fine filtration followed by metal oxide processing has been found to be an effective treatment process to upgrade the pyrolysis products for safe processing in the refining unit. The use of fine filtration and metal oxide processing allows efficient recycling in large quantities by integrating with the refinery.

[0010] In another embodiment, a continuous process is provided for converting waste plastics, including polyethylene, to be recycled for polyethylene polymerization. The process includes selecting waste plastics, including polyethylene and / or polypropylene, and then passing the waste plastics through a pyrolysis reactor to thermally decompose at least a portion of the polyolefin waste and generate a pyrolysis effluent. The pyrolysis effluent is separated into off-gas, pyrolysis oil (including naphtha, diesel, and heavy fractions), and char. The pyrolysis oil (the entire liquid fraction from the pyrolysis unit) is finely filtered and then metal oxide processed. The resulting treated pyrolysis product is safely passed to a refinery FCC unit. The FCC unit converts the treated pyrolysis oil product into FCC hydrocarbon products. The FCC product is sent to the FCC unit separation section to generate off-gas, C3, C4, FCC gasoline, and heavy fractions. A clean C3 liquefied petroleum gas (LPG) fraction, including propane and propylene, is collected from the separation section. This C3 stream is a suitable feedstock for a steam cracker. The C3 stream is fed to a steam cracker distillation section and separated into propane and propylene. The propane is then fed to a steam cracker and converted to pure ethylene. The ethylene is then polymerized into a polyethylene product.

[0011] The recovered FCC gasoline is sent to a gasoline blending pool. The heavy portion of the hydrocarbons from the FCC unit distillation is sent to an appropriate refining unit for upgrading to clean gasoline and diesel. The recovered C4 LPG fraction contains butanes and butenes and can also be sent to various upgrading processes to produce clean gasoline and diesel.

[0012] In one embodiment, the treated pyrolysis oil is passed through a refined FCC feed pretreatment unit prior to the FCC unit, which is effective in removing sulfur, nitrogen, phosphorus, silica, dienes, and metals that impair the catalytic performance of the FCC unit, and which also hydrogenates aromatic compounds and improves the liquid yield of the FCC unit.

[0013] It has been found that, among other factors, the addition of refinery operations can upgrade waste pyrolysis oil and waste pyrolysis wax to higher value products such as gasoline, diesel, and base oils. It has also been found that the addition of refinery operations can efficiently and effectively produce clean naphtha (C5-C8) or C4 or C3 from the waste pyrolysis oil for the production of ultimate polyethylene polymer. Positive economics are realized throughout the process from recycled plastic to polyethylene product with product quality equivalent to virgin polymer. Furthermore, it has been discovered that the most effective process is achieved by upgrading the pyrolysis oil before integration into refinery operations. The combined use of fine filtration and metal oxide treatment has been found to be most effective. Such filtration / metal oxide treatment of pyrolysis oil allows for the safe recycling of larger quantities of waste plastic. [Brief description of the drawings]

[0014] [Figure 1] Figure 1 shows the current practice of pyrolyzing waste plastics to produce fuel or wax (base case).

[0015] [Diagram 2] FIG. 2 shows the present process for filtration / metal oxide treatment of pyrolysis oil in a pyrolysis facility.

[0016] [Diagram 3] Figure 3 shows the process for establishing a circular economy from waste plastics to recycled polyethylene by following the process including filtration / metal oxide treatment of pyrolysis oil.

[0017] [Figure 4]Figure 4 shows the process for establishing a circular economy from waste plastics to recycled polyethylene, following the process including filtration / metal oxide treatment of pyrolysis oil carried out at the refinery.

[0018] [Diagram 5] Figure 5 shows the classification of plastic types for recycling waste plastics. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] This process provides a way to recycle waste polyethylene and / or waste polypropylene into virgin polyethylene and establish a circular economy by combining separate industrial processes. The majority of polyethylene and polypropylene polymers are used for single-use plastics and are discarded after use. This single-use plastic waste is becoming an increasingly important environmental issue. At present, there seem to be few options to recycle polyethylene and polypropylene waste plastics into value-added chemical and fuel products. Currently, only a small amount of polyethylene / polypropylene is recycled via chemical recycling, and this recycled and cleaned polymer pellets are pyrolyzed in pyrolysis units to produce fuels (naphtha, diesel), steam cracker feedstock, or slack wax.

[0020] Ethylene is the most produced petrochemical building block. Hundreds of millions of tons of ethylene are produced annually via steam cracking. Steam crackers use either gaseous feedstocks (ethane, propane and / or butane) or liquid feedstocks (naphtha or gas oil). Steam cracking is a non-catalytic decomposition process that takes place at very high temperatures, up to 850°C.

[0021] Polyethylene is widely used in a variety of consumer and industrial products. It is the most common plastic, with over 100 million tons of polyethylene resin produced annually. Its main use is in packaging (polyethylene bags, plastic films, geomembranes, bottles and other containers). Polyethylene is produced in three main forms, which have the same chemical formula (C2H4): n However, the molecular structure is different: high density polyethylene (HDPE, approximately 0.940-0.965 g / m -3 ), linear low density polyethylene (LLDPE, approx. 0.915-0.940g / cm -3 ), low density polyethylene (LDPE, <0.930g / cm -3 HDPE has low branching and short side chains, whereas LDPE has very high branching and long side chains. LLDPE is a substantially linear polymer with a significant number of short branches and is usually made by the copolymerization of ethylene with short chain alpha olefins.

[0022] Low density polyethylene (LDPE) is produced by radical polymerization at temperatures between 150 and 300 °C and very high pressures between 1,000 and 3,000 atm (101 and 304 MPa). This process uses small amounts of oxygen and / or organic peroxide initiators to produce polymers with about 4,000 to 40,000 carbon atoms per average polymer molecule and with a lot of branching. High density polyethylene (HDPE) is produced in the presence of a catalyst at relatively low pressures (10 to 80 atm, 1 to 8 MPa) and temperatures between 80 and 150 °C. Ziegler-Natta organometallic catalysts (titanium(III) chloride with aluminum alkyls) and Phillips-type catalysts (chromium(IV) oxide supported on silica) are typically used, and the production is carried out via a slurry process using a loop reactor or a gas-phase process using a fluidized bed reactor. Hydrogen is mixed with the ethylene to control the chain length of the polymer. The production conditions for linear low density polyethylene (LLDPE) are similar to those for HDPE, except for the copolymerization of ethylene with short chain alpha olefins (1-butene or 1-hexene).

[0023] Today, due to the inefficiencies mentioned above, only a small portion of post-consumer polyethylene and polypropylene products are collected for recycling efforts. This process allows for a much larger amount of single-use plastic waste to be safely recycled using a process integrated with a refinery, effectively establishing a circular economy.

[0024] Figure 1 shows a diagram of waste plastic fuel or wax pyrolysis as commonly practiced in the industry today. As mentioned above, typically polyethylene and polypropylene waste are sorted together (1). The cleaned polyethylene / polypropylene waste 2 is converted to off-gas 4 and pyrolysis oil (liquid products) in a pyrolysis unit 3. The off-gas 4 from the pyrolysis unit is used as fuel to operate the pyrolysis unit. A distillation unit within the pyrolysis unit separates the pyrolysis oil to produce naphtha and diesel 5 products, which are sold to the fuel market. The heavy pyrolysis oil fraction 6 is recycled to the pyrolysis unit 3 to maximize fuel yield. Char 7 is removed from the pyrolysis unit 3. The heavy fraction 6 is rich in long-chain linear hydrocarbons and is very waxy (i.e., forms paraffinic wax when cooled to ambient temperature). Wax can be separated from the heavy fraction 6 and sold to the wax market.

[0025] It has been discovered that upgrading pyrolysis oil before introduction into the refinery unit improves the effectiveness and safety of the overall process. More specifically, important materials that need to be removed from the pyrolysis product for co-feeding to the refinery unit include components such as residual char, metals, and chlorides. Pyrolysis products containing these impurities cannot be fed to the refinery unit in large quantities because the char and inorganic solids would cause blockage of the unit, the metals would permanently deactivate the refinery catalyst, and the chlorides would cause corrosion of the processing equipment. Reduction of chloride impurities is especially important before feeding to the refinery unit because chlorides can cause severe corrosion of the bare carbon steel that makes up most refinery units. Chloride corrosion is especially accelerated at the high temperatures above 500°F (260°C) at which most refinery units operate.

[0026] The pyrolysis product processing of the present process can be efficiently performed in combination with the pyrolysis unit during the production of pyrolysis oil and wax. Alternatively, the pyrolysis oil and wax can be processed in the refinery before being fed to the refining unit. The present process of fine filtration and metal oxide treatment does not reduce the S and N impurities, nor the olefin and diene content. In the current process for establishing a circular economy, the conversion of these compounds is effectively achieved by refining units such as fluid catalytic cracking (FCC) units, FCC feedstock pretreaters, refinery crude units, cokers, distillate hydrotreaters or hydrocrackers.

[0027] The process converts large volumes of waste plastics into pyrolyzed polyethylene and / or polypropylene by integrating the waste polymer pyrolysis product stream into an oil refinery operation. The resulting process produces polymer feedstock (naphtha or C3-C4 or C3, for ethylene crackers only), as well as high quality gasoline, jet and diesel fuels, and / or high quality base oils.

[0028] In general, the process provides a circular economy for polyethylene plants. Polyethylene is produced through the polymerization of pure ethylene. Clean ethylene can be produced using a steam cracker. Either naphtha or C3 or C4 streams can be fed to the steam cracker. The ethylene is then polymerized to produce polyethylene.

[0029] By adding refining operations to upgrade the waste pyrolysis oil to higher value products (gasoline and diesel, base oils) and to produce clean LPG and naphtha for the steam cracker for the production of ultimate polyethylene polymer, positive economics can be generated throughout the process from recycled plastics to a polyethylene product with quality equivalent to virgin polymer.

[0030] The pyrolysis unit produces low quality products containing contaminants such as calcium, magnesium, chlorides, nitrogen, sulfur, phosphorus, silicon, dienes, and heavy components, which cannot be used in large quantities for blending transportation fuels. It was discovered that by passing these products through a refinery unit, the contaminants can be captured in a pre-treatment unit and their adverse effects can be mitigated. The fuel components can be further upgraded in a suitable refinery unit with chemical conversion processes, and the final transportation fuel produced by the integrated process can be of higher quality and meet the fuel quality requirements. The process upgrades the wax to valuable gasoline, diesel, and base oils. The integrated process produces a much cleaner naphtha stream as a steam cracker feedstock for ethylene production and polyethylene manufacturing. The mass production of these products on spec makes a "circular economy" of recycled plastics possible.

[0031] However, it has been discovered that upgrading of the pyrolysis products is still necessary before the stream can be integrated with the refining unit, which is a critical aspect of the process. Pyrolysis oil and wax waste plastics contain multiple contaminants that cannot be fed in large quantities to the refining unit because they would deactivate the refining catalyst or cause clogging of the unit or cause severe corrosion in the processing units, which are generally made of bare carbon steel.

[0032] FIG. 2 shows a process sequence of microfiltration and metal oxide treatment. In FIG. 2, the washed polyethylene / polypropylene waste 22 is passed through a pyrolysis reactor 23 to thermally decompose at least a portion of the polyolefin waste and produce a pyrolyzed effluent. Char 26 is generally removed from the pyrolysis reactor 23. The effluent is passed through a heat exchanger 60 for partial cooling and then through a gas-liquid separation unit 61. Off-gas 24 can be used as fuel to operate the pyrolysis unit. The liquid product from the pyrolyzed effluent is then passed through a microfiltration unit 27-1. Optionally, the pyrolysis wax produced can also be sent to microfiltration (and metal oxide treatment).

[0033] The fine filtration unit removes solids in the pyrolysis oil, especially inorganic solids resulting from char and contamination produced by the pyrolysis process. Metals are often present as inorganic solids in the form of metal chlorides, metals or metal oxides. Thus, the fine filtration process reduces contaminants originating from char, metals, metal oxides and metal chlorides. Very fine filter media must be used, preferentially with a nominal filtration accuracy of less than 5 microns, more preferentially less than 2.5 microns and most preferentially less than 1 micron. Several filter units with different sizes of filter elements may be used in series. These filter media are well known for industrial applications. The filter media must be able to withstand the temperatures of the pyrolysis oil and especially the chemical nature of the contaminants. The residual solids content can be measured, for example, by the heptane insolubles test, ASTM D-3279 method. The heptane insolubles content must be reduced to less than 0.5% by weight, preferably less than 0.1%.

[0034] After filtration, the filtered liquid effluent is passed through metal oxide treatment 27-2. The metal oxide treatment removes organic chlorides and metals from the filtered pyrolysis oil. Chloride and impurity removal is more effective when the metal oxide treatment temperature is greater than 200°F (93°C), preferentially greater than 300°F (149°C), and most preferentially greater than 400°F (204°C). The preferred pressure range is from atmospheric to 1000 psig, preferentially from 0 psig to 600 psig. Optionally, H2 gas can be added to the treatment process to reduce metal oxide fouling and improve performance. The preferred amount of H2 gas flow is in the range of 0-2000 scf / bbl of pyrolysis oil. Metal oxides with high surface area can also capture additional contaminants. Metal oxides such as CaO, ZnO, MgO, alumina, silica, clay, and silica-alumina are effective for chloride removal. Mixed metal oxides made of Mg, Ca, Al, Zn, or combinations thereof are particularly effective at removing organic chlorides. It is desirable to reduce the chloride content to less than 10 ppm, preferably less than 5 ppm, and most preferably less than 1 ppm. Metal oxides made of Ni, Mo, phosphate, alumina, silica, silica-alumina, or combinations thereof are particularly effective at removing residual metals, but can also remove other contaminants such as chloride, nitrogen, phosphorus, and silicon. It is desirable to reduce the total residual metal content to less than 10 ppm, preferably less than 5 ppm. Combinations of different metal oxides can be used to effectively remove impurities.

[0035] The treated effluent may then be cooled in heat exchanger 62 and the total treated liquid product (naphtha, distillate and heavy ends) 25 may be sent to a purification unit 63 .

[0036] Figures 3 and 4 show the present integrated process, filtration and metal oxide processing, and the integration of refining operations and recycling for efficient polyethylene production. The same numbers in Figures 2, 3, and 4 refer to the same types of units and product streams. In Figures 3 and 4, mixed waste plastics are sorted together (21). The cleaned waste plastics 22 are converted in a pyrolysis unit 23 to off-gas 24 and pyrolysis oil (liquid products) and sometimes wax (solid products at ambient temperature). The off-gas 24 from the pyrolysis unit can be used as fuel to operate the pyrolysis unit 23. The pyrolysis oil (total liquid products 25) includes naphtha / diesel distillate / heavy fractions. After the pyrolysis process is completed, char 26 is removed from the pyrolysis unit 23.

[0037] The pyrolysis unit can be located near the waste plastic collection site, which can be remote from the refinery, near the refinery, or within the refinery. If the pyrolysis unit is located remote from the refinery, the pyrolysis oil (naphtha / diesel and heavy oil) can be transported to the refinery by truck, barge, rail car, or pipeline. However, it is preferred that the pyrolysis unit be located at the waste plastic collection site or within the refinery.

[0038] In FIG. 3, fine filtration and metal oxide treatment 27 are performed in the pyrolysis facility. The total liquid pyrolysis product 25 from pyrolysis unit 23 is sent to a filtration unit followed by oxide treatment. The hot pyrolysis liquid is preferably filtered and treated with metal oxides before being fully cooled to ambient temperature for storage and / or transport. Thus, filtration and metal oxide treatment are preferably performed in the pyrolysis facility after the total liquid product 25 has been collected or simultaneously with the total liquid product collection step. The treated liquid product can then be transported to a refinery.

[0039] In Figure 4, in another embodiment, the entire liquid product 25 is transferred to a refinery. Microfiltration and metal oxide processing 27 is completed at the refinery.

[0040] The preferred starting material for the process is sorted waste plastics containing mainly polyethylene and polypropylene (plastic recycling classification types 2, 4, and 5). The pre-sorted waste plastics are washed, shredded or pelletized, and fed to a pyrolysis unit for pyrolysis. Figure 5 shows the plastic type classification for waste plastic recycling. Classification types 2, 4, and 5 are high density polyethylene, low density polyethylene, and polypropylene, respectively. Polyethylene and polypropylene waste plastics can be used in any combination. It is preferred to use at least some polyethylene waste plastics in the process.

[0041] Proper sorting of waste plastics is very important to minimize contaminants such as N, Cl, and S. Plastic waste including polyethylene terephthalate (Plastic Recycle Classification Type 1), polyvinyl chloride (Plastic Recycle Classification Type 3) and other polymers (Plastic Recycle Classification Type 7) should be sorted to less than 5%, preferably less than 1%, and most preferably less than 0.1%. The process can tolerate moderate amounts of polystyrene (Plastic Recycle Classification Type 6). Waste polystyrene should be sorted to less than 30%, preferably less than 20%, and most preferably less than 5%.

[0042] Washing of waste plastics removes metallic contaminants such as sodium, calcium, magnesium, aluminum, and non-metallic contaminants from other waste sources. Non-metallic contaminants include contaminants from Group IVA of the Periodic Table such as silica, contaminants from Group VA such as phosphorus and nitrogen compounds, contaminants from Group VIA such as sulfur compounds, and halide contaminants from Group VIIA such as fluorides, chlorides, iodides, etc. Residual metal, non-metallic contaminants, and halides should be removed to less than 50 ppm, preferentially less than 30 ppm, and most preferentially less than 5 ppm.

[0043] Pyrolysis is carried out by contacting the plastic material feedstock under pyrolysis conditions in a pyrolysis zone, where at least a portion of the feedstock is decomposed, thereby forming a pyrolysis zone effluent containing primarily 1-olefins and n-paraffins. The pyrolysis conditions include a temperature of about 400°C to about 700°C, preferably about 450°C to about 650°C. Conventional pyrolysis techniques teach operating conditions at pressures above atmospheric pressure (see, for example, U.S. Pat. No. 4,642,401). Furthermore, it has been found that the yield of desired products can be controlled by adjusting the pressure downward (see, for example, U.S. Pat. No. 6,150,577). Thus, in some embodiments where such control is desired, the pyrolysis pressure is below atmospheric pressure.

[0044] It has been discovered that the use of fine filtration (e.g., filters with pore sizes of 5.0 microns or less, preferably 1.0 microns or less, and in one embodiment 0.5 microns) followed by metal oxide treatment is highly beneficial in achieving a feed stream that can be efficiently passed through a refinery without problems such as corrosion, clogging, or catalyst deactivation. This treatment allows the bulk of the waste plastic pyrolysis liquid products to be passed through a refinery, resulting in the most efficient recycling process.

[0045] Figure 3 shows this integrated process in which the entire pyrolysis oil (naphtha, distillate and heavy fractions) after filtration and metal oxide treatment 27 is sent to a fluid catalytic cracking (FCC) unit 28. Optionally, only a portion of the pyrolysis oil (only the distillate and heavy fractions, or only the heavy fractions) can be sent to the FCC unit. In Figure 3, filtration and metal oxide treatment 27 occurs in the pyrolysis facility.

[0046] The fluid catalytic cracking (FCC) process is widely used in the refining industry to convert atmospheric gas oil, vacuum gas oil, atmospheric residua, and heavies recovered from other refining operations into high octane gasoline, light and heavy fuel oil, olefin-rich light gas (LPG), and coke. FCC uses highly active zeolite catalysts to crack heavy hydrocarbon molecules at reactor temperatures of 950-990°F (510-532°C) in the riser with short contact times of a few minutes or less. LPG streams containing olefins (propylene, butylene) are typically upgraded to produce alkylate gasoline or for use in the manufacture of chemical products. Conventional FCC units are used.

[0047] Cracking of pyrolysis liquids combined with petroleum-derived oil in an FCC unit produces liquefied petroleum gas (LPG) olefin streams 31 and 32, as well as gasoline 29 and heavy fractions 30. - Off-gas 33 is also produced.

[0048] Refineries generally have their own supply of hydrocarbons from petroleum-derived oils flowing through the refining unit. The volume of the pyrolysis oil stream generated from the pyrolysis of waste plastics and flowing to the refining unit can constitute any practical or containable volume percent (vol%) of the total flow (total flow rate) to the refining unit. In general, the flow rate of pyrolysis oil (and wax) generated from the pyrolysis of waste plastics can be up to about 50 vol% of the total flow rate (i.e., refining flow rate and pyrolysis flow rate) for practical reasons. In one embodiment, the pyrolysis oil flow rate is up to about 20 vol% of the total flow rate. In another embodiment, the pyrolysis oil flow rate is up to about 10 vol% of the total flow rate. It has been found that about 20 vol% is a very practical amount in terms of impact on the refinery, while at the same time providing good results and being a containable amount. Of course, the amount of pyrolysis oil and wax generated from pyrolysis can be controlled so that the fraction passed to the refining unit provides the desired volume percent of the flow rate.

[0049] The LPG olefin stream 31 is a C3 liquefied petroleum gas (LPG) fraction that contains propane and propylene. This C3 stream is a suitable feedstock for a steam cracker. The C3 stream 31 is fed to a steam cracker 34. The C3 stream can also be fed to a distillation section of the steam cracker to separate the propane and propylene. In the steam cracker 34, the propane stream is converted to pure ethylene, which is then polymerized (40). The polyethylene can then be used to produce a polyethylene product 41.

[0050] The FCC gasoline 29 can be sent to a gasoline blending pool. The heavy fraction 30 recovered from the FCC unit 28 is sent to a suitable refining unit 38 (such as a hydrotreating, hydrocracking and / or coker unit) for upgrading to cleaner gasoline and diesel 39. The C4 stream 32 is sent to a gasoline blending pool or is further upgraded to cleaner gasoline (via processes such as alkylation or C4 olefin dimerization or ether synthesis).

[0051] In another embodiment, the treated pyrolysis oil is first sent to an FCC feed pretreatment unit (not shown) prior to the FCC unit. The FCC feed pretreatment unit typically uses a bimetallic (NiMo or CoMo) alumina catalyst in a fixed bed reactor to hydrogenate the feed with a H2 gas stream at a reactor temperature of 660-780°F (349-415°C) and a pressure of 1,000-2,000 psi (6.89-13.79 MPa). The refined FCC feed pretreatment unit is effective in removing sulfur, nitrogen, phosphorus, silica, dienes, and metals that impair the catalytic performance of the FCC unit. The unit also hydrogenates aromatic compounds, improving the liquid yield of the FCC unit.

[0052] FIG. 4 shows this integrated process in which the entire pyrolysis oil (naphtha, distillate and heavy fraction) is sent to a fluid catalytic cracking (FCC) unit 28. Optionally, only a portion of the pyrolysis oil (only the distillate and heavy fraction, or only the heavy fraction) can be sent to the FCC unit. Before being sent to the FCC unit, the pyrolysis oil is finely filtered and metal oxide treated (27). In FIG. 4, the filtration and metal oxide treatment take place at the refinery. The pyrolysis oil 25 is transferred to the refinery for processing 27.

[0053] Similar to FIG. 3, cracking the treated pyrolysis liquids combined with petroleum-derived oil in an FCC unit produces liquefied petroleum gas (LPG) olefin streams 31 and 32, as well as gasoline 29 and heavy fractions 30. - Off-gas 33 is also produced.

[0054] The LPG olefin stream 31 is a C3 liquefied petroleum gas (LPG) fraction that contains propane and propylene. This C3 stream is a suitable feedstock for a steam cracker. The C3 stream 31 is fed to a steam cracker 34. In the steam cracker 34, the C3 stream is converted to pure ethylene, which is then polymerized (40). The polyethylene can then be used to produce a polyethylene product 41.

[0055] The LPG olefins stream 32 is a C4 liquefied petroleum gas (LPG) fraction that includes butanes and butenes, which may be sent to a refinery alkylation unit 35 (not shown).

[0056] The FCC gasoline 29 may be sent to a gasoline blending pool. The heavy fraction 30 recovered from the FCC unit 28 is sent to a suitable refining unit 38 for upgrading to clean gasoline and diesel 39.

[0057] In another embodiment, the treated pyrolysis oil is first sent to an FCC feed pretreatment unit (not shown). The FCC feed pretreatment unit typically uses a bimetallic (NiMo or CoMo) alumina catalyst in a fixed bed reactor to hydrogenate the feed with a H2 gas stream at a reactor temperature of 660-780°F (349-415°C) and a pressure of 1,000-2,000 psi (6.89-13.79 MPa). The refined FCC feed pretreatment unit is effective in removing sulfur, nitrogen, phosphorus, silica, dienes, and metals that impair the catalytic performance of the FCC unit. The unit also hydrogenates aromatic compounds, improving the liquid yield of the FCC unit.

[0058] Alternatively, instead of sending the C3 olefins / paraffins mixture 31 recovered from the FCC unit directly to the steam cracker 34, the C3 olefins / paraffins mixture stream 31 is sent to a propane / propylene (PP) splitter, which is a highly efficient distillation column. From the propane / propylene splitter, a pure propane stream is recovered. The pure propane fraction is then passed to the steam cracker 34 for ethylene production. The propylene may be polymerized separately to produce polypropylene consumer products.

[0059] The ethylene polymerization unit is preferably located near the refinery so that the feedstocks (propane, butane, naphtha) can be transported via pipeline. For petrochemical plants located remotely from the refinery, the feedstocks can be delivered via truck, barge, rail car, or pipeline.

[0060] The carbon going in and out of the refinery is “transparent,” meaning that not all molecules from the waste plastics are cycled back into the polyolefin plant and become the exact olefin product, but it is nevertheless considered a “credit” since the net “green” carbon going in and out of the refinery is positive. These integrated processes result in a significant reduction in the amount of virgin feedstock required for a polyethylene plant.

[0061] The benefits of a circular economy and effective, efficient recycling campaigns are realised through this integrated process: through the use of fine filtration and metal oxide processing, larger volumes of feedstock can be cycled through the refinery safely and efficiently.

[0062] The following non-limiting examples illustrate this process and its advantages. EXAMPLES

[0063] Example 1: Characterization of pyrolysis oils and waxes from commercial sources

[0064] Pyrolysis oil and wax samples were obtained from commercial sources. Their properties are summarized in Table 1. These pyrolysis samples were prepared from waste plastics, mainly containing polyethylene and polypropylene, via pyrolysis in a pyrolysis reactor at approximately 400-600 °C and near atmospheric pressure without the addition of gas or catalyst. Pyrolysis units typically produce gas, liquid oil products, optional wax products, and char. The overhead gas stream of the pyrolysis unit containing the thermally decomposed hydrocarbons was cooled and the condensate was collected as pyrolysis oil (liquid at ambient temperature) and / or pyrolysis wax (solid at ambient temperature). Pyrolysis oil is the primary product of the pyrolysis unit. Some pyrolysis units produce pyrolysis wax as a separate product in addition to pyrolysis oil. [Table 1]

[0065] Specific gravity measurements were performed using ASTM D4052. Simulated boiling point distribution curves were obtained using ASTM D2887. Carlo-Erba analysis for carbon and hydrogen was performed according to ASTM D5291. Bromine number measurements were performed according to ASTM D1159. Hydrocarbon type analysis was performed using a high resolution magnetic mass spectrometer, scanning the magnet from 40 to 500 Daltons. Total sulfur was determined using XRF according to ASTM D2622. Nitrogen was determined using chemiluminescence detection according to a modified ASTM D5762. Total chloride content was typically measured using a combustion ion chromatography (CIC) instrument according to a modified ASTM 7359. Oxygen content in the boiling range of naphtha and distillate was estimated using GC with GC / MS measurement equipped with an electron ionization detector in the m / Z range of 29 to 500. Trace metallic and non-metallic elements in the oils were determined using inductively coupled plasma atomic emission spectrometry (ICP-AES).

[0066] Industrial pyrolysis processes of sorted plastics, sourced primarily from polyethylene and polypropylene waste, have produced high-quality hydrocarbon streams with specific gravities in the range of 0.7-0.9 and boiling points in the range of 18-1100°F, as in the case of pyrolysis oil or pyrolysis wax.

[0067] The pyrolysis products are fairly pure hydrocarbons consisting mainly of carbon and hydrogen. The hydrogen to carbon molar ratio varies from 1.7 to nearly 2.0. The bromine numbers range from 14 to 60, indicating varying degrees of unsaturation due to olefins and aromatics. The aromatic content ranges from 5 to 23 vol%, with more severe pyrolysis units producing more aromatics. Depending on the process conditions of the pyrolysis unit, the pyrolysis products show paraffin contents ranging from the mid-20s to the mid-50s vol.%. The pyrolysis products contain significant amounts of olefins. Samples A and B are pyrolysis oils produced under more severe conditions, such as higher pyrolysis temperatures and / or longer residence times, which result in higher aromatics and less paraffin, with H / C molar ratios of about 1.7 and high bromine numbers of 50 to 60. Samples C and D were produced under less severe conditions and their pyrolysis oils are more paraffinic, resulting in H / C molar ratios closer to 2.0 and bromine numbers around 40. Sample E (pyrolysis wax) is mostly paraffinic saturated hydrocarbons with a significant amount of linear (as opposed to branched) hydrocarbons and a bromine number of only 14.

[0068] [Example 2] Microfiltration to remove contaminants and solids from pyrolysis oil

[0069] The pyrolysis oil or wax products contain residual solids and other impurities that can adversely affect the performance of the refinery conversion units. The as-received pyrolysis oil samples were vacuum filtered through 0.7 micron glassfiber filter paper to remove residual solids. The results are summarized in Table 2.

[0070] Residual solids content can be measured by heptane insoluble test (ASTM D-3279 method). Chloride analysis was performed using X-ray fluorescence (XRF) method. [Table 2]

[0071] In this study, the filter pore size was found to be important for impurity removal. When a 25 micron filter was used, the filter paper became clogged and filtration of the three pyrolysis oils was not completed. When a 0.7 micron filter was used, filtration reduced the heptane insoluble solids content by more than 90%. This study showed that filtration when using small pore size filters (e.g., 1.0 micron or smaller filters such as 0.7 micron filters) was effective in removing residual solids. Surprisingly, filtration also effectively removed chloride impurities (Examples 2-1 through 2-4) except in one case (Example 2-5). The data suggests that the pyrolysis oil products contain varying amounts of inorganic chloride species and that filtration can significantly reduce impurity levels. However, in Example 2-5, no reduction in chloride species was observed. This suggests that some chloride species are organic in nature and require further processing beyond the filtration process.

[0072] [Example 3] Pretreatment of pyrolysis oil by filtration followed by metal oxide treatment using CaO / ZnO / clay

[0073] The as-received pyrolysis oil (Sample F) was filtered through a continuous filtration unit equipped with a nominal 0.5 micron filter cartridge to prepare filtered oil (Sample F-1). These samples were analyzed for general feed characteristics and impurities, as shown in Table 3. [Table 3]

[0074] A continuous filtration unit equipped with nominal 0.5 micron filter cartridges was effective, reducing the heptane insoluble solids content by 87%, producing a filtered oil (Sample F-1) with residual heptane insoluble solids of 314. Filtration also removed significant amounts of other impurities, including nitrogen, chloride, iron, phosphorus, and silicon.

[0075] Sample F-1 was further processed by passing it through a fixed bed reactor containing a metal oxide sorbent made of CaO / ZnO / clay. The metal oxide processing experiments were carried out at a reactor pressure of 600 psig and a flow rate of 1 LHSV, with temperatures varying from 200 to 400°F. 1500 SCF / BBL of hydrogen was fed to the reactor along with the oil. The results are summarized in Table 4 below. [Table 4]

[0076] The metal oxide treatment process removed significant amounts of metals (Fe) and other non-metals (N, Cl, P, Si) that could adversely affect the performance of the refinery's conversion units. CaO and ZnO containing metal oxides were particularly effective at removing chlorides and iron. Removal was more efficient at higher temperatures.

[0077] [Example 4] Pretreatment of pyrolysis oil by filtration followed by metal oxide treatment using NiO / MoO3 / PO4 / alumina

[0078] The as-received pyrolysis oil (Sample G) was filtered through a continuous filtration unit equipped with a nominal 0.5 micron filter cartridge to prepare filtered oil (Sample G-1). These samples were analyzed for general feed characteristics and impurities as shown in Table 5. [Table 5]

[0079] The data in Table 5 show that a continuous filtration unit with nominal 0.5 micron filter cartridges was effective in reducing impurities such as nitrogen, chloride, calcium, chromium, iron, magnesium, and silicon. However, filtration did not remove sulfur and phosphorus impurities.

[0080] Sample G-1 was further processed by passing it through a fixed bed reactor containing a metal oxide sorbent made of NiO / MoO3 / PO4 / alumina. The metal oxide processing experiments were carried out at a reactor pressure of 400 psig and a flow rate of 1 LHSV, with temperatures varying from 500 to 550°F. 1500 SCF / BBL of hydrogen was fed to the reactor along with the oil. The results are summarized in Table 6 below. [Table 6]

[0081] The metal oxide treatment process removed significant amounts of metals (Fe, Ca, Cr, Mg) and other non-metals (N, Cl, P, Si) that could adversely affect the performance of the refinery's conversion units. MoO3 and NiO-containing metal oxides were particularly effective at removing metals at temperatures between about 500 and 550°F.

[0082] The following Examples 5 to 8 show the evaluation of waste plastic pyrolysis oil as a transportation fuel.

[0083] [Example 5] Fractional distillation of pyrolysis oil for evaluation as a transportation fuel

[0084] Sample D was distilled to separate multiple fractions of hydrocarbons, namely, gasoline (350° F. - ) fraction, jet (350-572°F) fraction, diesel (572-700°F) fraction, and heavy (700°F + Table 7 summarizes the boiling point distribution and impurity distribution of each fraction of the distillation product. [Table 7]

[0085] [Example 6] Evaluation of pyrolysis oil fractions for gasoline fuel

[0086] Sample H (a fraction of pyrolysis oil with a boiling point range for gasoline fuel) was evaluated for its usability as a gasoline fuel. The carbon number range of Sample H is C5 to C12, which is typical for gasoline fuel.

[0087] Because pyrolysis oils are olefinic in nature, oxidation stability (ASTM D525) and gum formation tendency (ASTM D381) were identified as the most important properties to be investigated. Research Octane Number (RON) and Motor Octane Number (MON) are also important properties for engine performance. RON and MON values ​​were estimated from detailed GC analysis of the hydrocarbons. [Table 8]

[0088] Sample H (a fraction of pyrolysis oil in the boiling range of gasoline fuel) is of poor quality and cannot be used alone as a gasoline fuel for motor vehicles. The gasoline fraction from pyrolysis oil showed very poor oxidation stability in that sample H failed after only 90 minutes compared to the target stability of over 1440 minutes. The pyrolysis gasoline exceeded the wash gum target of 4 mg / 100 mL, indicating a strong tendency for gum formation. The pyrolysis gasoline has a lower octane number compared to the reference gasoline. Premium unleaded gasoline was used as the reference gasoline.

[0089] The possibility of blending limited amounts of pyrolysis gasoline fractions into the reference gasoline was also investigated. This study showed that up to 15% by volume of sample H could potentially be blended into refined gasoline while still achieving the fuel property targets. By integrating pyrolysis gasoline products with refined fuels, the overall product quality can be maintained.

[0090] These results indicate that the as-produced gasoline fraction of pyrolysis oil has limited usefulness as a gasoline fuel. Upgrading in a refinery unit is required to convert the gasoline fraction of pyrolysis oil into hydrocarbons that meet gasoline fuel property targets.

[0091] [Example 7] Evaluation of pyrolysis oil fractions for jet fuel

[0092] Sample I (a fraction of pyrolysis oil with a boiling point range equivalent to that of jet fuel) was evaluated for its potential use as jet fuel. The carbon number range of Sample I is C9 to C18, which is typical of jet fuel.

[0093] Because pyrolysis oil is olefinic, the jet fuel thermal oxidation test (D3241) was considered the critical test. Sample I, the pure jet fraction of pyrolysis oil, had an oxidative stability of only 36 minutes, indicating that the pure pyrolysis jet fraction is unsuitable for use as jet fuel.

[0094] A 5% by volume blend of the pyrolysis jet fraction (Sample I) into refinery produced jet fuel was prepared. This blend still failed the jet fuel oxidation test, as shown in Table 9. [Table 9]

[0095] These results indicate that the as-produced jet fraction of pyrolysis oil is completely unsuitable for jet fuel and that upgrading in a refining unit is necessary to convert this jet fraction of pyrolysis oil into hydrocarbons that meet the property targets for jet fuel.

[0096] [Example 8] Evaluation of pyrolysis oil fractions for diesel fuel

[0097] Sample J (a fraction of pyrolysis oil with a boiling point range for diesel fuel) was evaluated for its potential use as diesel fuel. The carbon number range of Sample J is C14 to C24, which is typical for diesel fuel.

[0098] Sample J contains a significant amount of normal hydrocarbons, which tend to exhibit wax-like properties, so cold flow properties such as pour point (ASTM D5950-14) and cloud point (ASTM D5773) were considered the most important tests.

[0099] Two blends were prepared by blending 10% and 20% by volume of Sample J into refinery produced diesel fuel, but both blends still failed the target pour point of less than -17.8°C (0°F). [Table 10]

[0100] These results indicate that pyrolysis oil as is is completely unsuitable for diesel fuel and that upgrading in a refinery unit is required to convert the diesel fraction of pyrolysis oil into hydrocarbons that meet the property targets for diesel fuel.

[0101] [Example 9] Co-processing of pyrolysis products into FCC units

[0102] As shown in Figure 3, by feeding the entire pyrolysis feedstock to the FCC unit after pretreatment of the feedstock, the pyrolysis oil and wax are converted into off-gas, LPG paraffins and olefins, FCC gasoline and heavy hydrocarbon components. FCC gasoline is a valuable gasoline blending component. The heavy fraction, light cycle oil (LCO) and heavy cycle oil (HCO) are further converted in subsequent conversion units including jet hydrotreating unit, diesel hydrotreating unit, hydrocracking unit and / or coker unit to produce more gasoline, jet and diesel fuel with satisfactory product properties. The LPG paraffins and olefins can be further processed in the alkylation unit or partially used for the production of petrochemical products with recycled components.

[0103] Examples 10 and 11 below demonstrate the conversion of waste plastic pyrolysis products into high quality transportation fuels in a refinery and conversion unit (using an FCC unit as an example).

[0104] [Example 10] Conversion of pyrolysis oil in FCC

[0105] To investigate the effect of coprocessing waste plastic pyrolysis oil in FCC, a series of laboratory tests were carried out using Sample A and Sample C. Vacuum gas oil (VGO) is a typical feedstock for FCC. The FCC performance of a 20 vol.% blend of pyrolysis oil with VGO and pure pyrolysis oil was compared with that of pure VGO feedstock.

[0106] FCC experiments were performed in a Model C ACE (advanced cracking evaluation) unit manufactured by Kayser Technology Inc., using regenerated equilibrium catalyst (Ecat) from a refinery. The reactor was a fixed flow reactor using N2 as the fluidizing gas. Catalytic cracking experiments were performed at atmospheric pressure and a reactor temperature of 900°F. The catalyst / oil ratio was varied between 5 and 8 by varying the amount of catalyst. Gas products were collected and analyzed using a refinery gas analysis unit (RGA) equipped with a GC with FID detector. In-situ regeneration of spent catalyst was performed in the presence of air at 1300°F, and the regenerated flue gas was passed through a LECO to determine the coke yield. Liquid products were weighed and analyzed by GC for simulated distillation (D2887) and C5 - Compositional analysis was performed. Mass balance showed that the crude oil was composed of coke, dry gas components, LPG components, gasoline (C5, ~430°F), light cycle oil (LCO, 430-650°F), and heavy cycle oil (HCO, 650°F). + The yield of 1,2-dichloro-1,2-diphenyl-2,3-diphenyl-1,4-tetrahydrofuran (1,2-diphenyl-2,4-diphenyl-1,5-dimethyl-2,6-dimethyl-2,7-dimethyl-2,8-diphenyl-1,5 ...7- [Table 11]

[0107] The results in Table 11 show that co-feeding up to 20% by volume of pyrolysis oil only results in a negligible change in the performance of the FCC unit, indicating that co-processing up to 20% of pyrolysis oil is readily feasible. Blending 20% ​​by volume of Sample A or Sample C resulted in a negligible decrease in coke and dry gas yields, a slight increase in gasoline yield, and a slight decrease in LCO and HCO, which are favorable in most situations. Because pyrolysis oil is paraffinic, blending 20% ​​of Sample A or Sample C resulted in a decrease in octane number of about 3-5. Depending on the operational flexibility of the refinery, these octane losses can be compensated for by adjusting the blending or feed position.

[0108] The FCC unit cracks the pyrolysis oil into fuel range hydrocarbons, reduces impurities, and isomerizes n-paraffins to isoparaffins. All these chemical properties improve the fuel properties of the pyrolysis oil and wax. By co-feeding the pyrolysis oil through the FCC process unit with a zeolite catalyst, the fuel range oxygen and nitrogen impurities were significantly reduced from about 300-1400 ppm nitrogen (N) to about 30 ppm and from about 250-540 ppm oxygen (O) to about 60-80 ppm. The hydrocarbon composition of all these co-feed products is well within the range of typical FCC gasoline.

[0109] FCC operation of 100% pyrolysis oil showed a significant octane minus (minus about 13–14), indicating that co-processing of pyrolysis oil is preferable over processing of pure 100% pyrolysis oil.

[0110] [Example 11] Co-processing of pyrolysis wax in FCC

[0111] A series of laboratory tests were conducted using Sample E and VGO to study the effect of coprocessing waste plastic pyrolysis wax in FCC. As in Example 10, the FCC performance of a 20% blend of pyrolysis wax with VGO and pure pyrolysis wax was compared to the FCC performance of pure VGO feedstock. The results are summarized in Table 12 below. [Table 12]

[0112] The results in Table 12 show that co-feeding up to 20% by volume of pyrolysis wax results in only a negligible change in the FCC unit performance, indicating that co-processing of up to 20% pyrolysis wax is readily feasible. Blending 20% ​​by volume of Sample E resulted in little change in coke and dry gas yields, a significant increase in LPG olefins yield, a negligible increase in gasoline yield, and a slight decrease in LCO and HCO, which are favorable in most situations. Because pyrolysis oil wax is paraffinic, blending 20% ​​of Sample E resulted in a slight octane loss of 1.5. Due to the refinery's blending flexibility, this octane loss can easily be made up with minor blend adjustments.

[0113] FCC operation of 100% pyrolysis wax showed a significant increase in conversion and a negative octane number (negative 6), indicating that co-processing of pyrolysis wax is preferable over processing of 100% pyrolysis wax.

[0114] [Example 12] Feeding of recycled C3LPG stream to a steam cracker for the production of ethylene and subsequent production of polyethylene resin and polyethylene consumer products

[0115] As shown in FIG. 3, the C3LPG stream containing propane and propylene produced via co-feeding the pyrolysis products to the FCC unit is separated and fed to a steam cracker to produce ethylene containing recycled content. The ethylene is then processed to a polymerization unit to produce polyethylene resin containing recycled polyethylene / polypropylene derived material. The newly produced polyethylene has high quality that is indistinguishable from virgin polyethylene made entirely from virgin petroleum resources. This polyethylene resin containing recycled material is further processed to produce various polyethylene products that meet consumer product needs. Although these polyethylene consumer products contain chemically recycled circular polymers, the quality of these products is indistinguishable from those made from entirely virgin polyethylene polymers. These chemically recycled polymer products are different from mechanically recycled polymer products that are inferior in quality to polymer products made from virgin polymers.

[0116] [Example 13] Manufacturing high-quality gasoline, jet, and diesel products containing recycled content

[0117] As shown in Examples 10 and 11, co-feeding pyrolysis oil and / or wax to the FCC unit produces significant amounts of C3-C5 olefins with recycle content, as well as gasoline, jet and diesel products. A C4-only or C4-C5 stream containing recycled olefins is separated from the FCC light ends recovery unit and fed to the alkylation unit. Reaction of LPG olefins with isobutane in the alkylation reactor produces n-butane and alkylate gasoline with recycle content. Alkylate gasoline and n-butane are valuable gasoline blending components. The heavy fraction is further upgraded in a hydrocracking unit to produce high quality gasoline, jet and diesel products.

[0118] The above mentioned examples clearly show a new and effective way to recycle large amounts of polyethylene and polypropylene derived waste plastics by chemical recycling via pyrolysis followed by co-feeding of pyrolysis products with refineries via efficient integration. These examples also show the benefits of filtration / metal oxide treatment prior to the FCC unit. This integration allows the production of high quality fuels and circular polymers.

[0119] As used in this disclosure, the words "comprises" or "comprising" are intended as open-ended transitional phrases, meaning the inclusion of the indicated elements, but not necessarily the exclusion of other unspecified elements. The phrase "consists essentially of" or "consisting essentially of" is intended to mean excluding other elements that are essential to the composition. The phrase "consisting of" or "consists of" is intended as a transitional phrase, meaning the exclusion of all other than the recited elements, except for only trace impurities.

[0120] All patents and publications referenced herein are incorporated herein by reference to the extent not inconsistent therewith. It will be understood that the specific above-described structures, functions, and operations of the above-described embodiments are not necessary to practice the present invention, but are included in the description merely to complete the exemplary embodiment or embodiments. It will be further understood that the specific structures, functions, and operations described in the above-referenced patents and publications can be practiced in combination with the present invention, but are not essential to its practice. Thus, it should be understood that the present invention can be practiced as specifically described without actually departing from the spirit and scope of the present invention, as defined by the appended claims. The contents of the invention according to the claims as originally filed in this application are as follows: [Section 1] A continuous process for converting waste plastics into recycling for polyethylene polymerization, comprising: (a) selecting waste plastics comprising polyethylene and / or polypropylene; (b) passing the waste plastic from (a) through a pyrolysis reactor to thermally decompose at least a portion of the polyolefin waste and produce a pyrolyzed effluent; (c) separating the pyrolysis effluent into off-gas, pyrolysis oil (including naphtha, diesel and heavy fractions), and char; (d) subjecting the pyrolysis oil from (c) to a filtration / metal oxide treatment; (e) recovering the treated pyrolysis oil and passing it through a refinery FCC unit; (f) Liquefied petroleum gas C from the FCC unit. 3 recovering the olefin / paraffin mixture fraction; (g) The liquefied petroleum gas C 3 passing the olefin / paraffin mixture fraction through a steam cracker for producing ethylene; The above process comprising: [Section 2] Item 1. The process of claim 1, wherein gasoline and heavy fractions are recovered from a refinery FCC unit. [Section 3] The process according to item 1, wherein the ethylene produced in (g) is then polymerized. [Section 4] Item 4. The process of item 3, wherein the polyethylene product is prepared from polymerized ethylene. [Section 5] Item 3. The process of item 2, wherein the amount of gasoline produced by the FCC unit is increased with recycled pyrolysis oil. [Section 6] Item 3. The process according to item 1, wherein the filtration uses a filter having pores with an average diameter of 5 microns or less. [Section 7] 7. The process of claim 6, wherein the average diameter of the pores is less than 1 micron. [Section 8] The metal oxide treatment is CaO, ZnO, MgO, NiO, MoO 3 Item 1. The process of item 1, comprising a metal oxide selected from the group consisting of alumina, silica, silica-alumina, or clay, or mixtures thereof. [Section 9] Item 1. The process of item 1, wherein the metal oxide treatment is carried out at a temperature greater than 200° F. (93° C.). [Section 10] Item 1. The process of item 1, wherein the waste plastics selected in (a) are from plastic classification groups 2, 4, and / or 5. [Section 11] Item 1. The process of item 1, wherein the filtration / metal oxide treatment is carried out in a refinery that includes an FCC unit. [Section 12] Item 1. The process of item 1, wherein the filtration occurs in a pyrolysis facility and the metal oxide processing occurs in a refinery that includes an FCC unit. [Section 13] Item 1. The process of item 1, wherein after filtration, the heptane insoluble content is reduced to less than 0.1 wt.%. [Section 14] Item 1. The process of item 1, wherein after metal oxide treatment, the chloride content is reduced to less than 5 ppm. [Section 15] Item 1. The process of item 1, wherein after metal oxide treatment, the total metal impurity content is less than 10 ppm. [Section 16] The process of item 1, wherein in (d) filtration / metal oxide treatment, solid particulate and chloride reduction is achieved, and in the refinery FCC unit, S, diene, olefin, and N reduction is achieved. [Section 17] Item 1. The process of item 1, wherein only the diesel and heavy fractions of the pyrolysis oil, or only the heavy fractions of the pyrolysis oil, are passed through filtration and metal oxide treatment. [Section 18] The process of claim 1, wherein the treated pyrolysis oil recovered in (e) is first passed through an FCC pretreatment unit from which an effluent is recovered, and the recovered effluent is passed through a refinery FCC unit. [Section 19] Item 19. The process of item 18, wherein in (d) filtration / metal oxide treatment, solid particulate and chloride reduction is achieved, and in the FCC feed pretreatment unit, S, diene, olefin and N reduction is achieved. [Section 20] A continuous process for converting waste plastics into recycling for polyethylene polymerization, comprising: (a) selecting waste plastics comprising polyethylene and / or polypropylene; (b) passing the waste plastic from (a) through a pyrolysis reactor to thermally decompose at least a portion of the polyolefin waste and produce a pyrolyzed effluent; (c) separating the pyrolysis effluent into off-gas, pyrolysis oil (including naphtha, diesel and heavy fractions), and char; (d) subjecting the pyrolysis oil from (c) to a filtration / metal oxide treatment; (e) recovering the treated pyrolysis oil and sending it to a refinery; The above process comprising: [Section 21] Item 21. The process according to item 20, wherein the filtration uses a filter having pores with an average diameter of 5 microns or less. [Section 22] 22. The process of claim 21, wherein the average diameter of the pores is less than 1 micron. [Section 23] 21. The process of claim 20, wherein the metal oxide treatment comprises a metal oxide selected from CaO, ZnO, MgO, alumina, silica or silica-alumina, or mixtures thereof. [Section 24] 21. The process of claim 20, wherein the metal oxide treatment is carried out at a temperature greater than 200° F. (93° C.). [Section 25] Item 21. The process of item 20, wherein after filtration, the heptane insoluble content is reduced to less than 0.1 wt.%. [Section 26] 21. The process of claim 20, wherein after metal oxide treatment, the chloride content is reduced to less than 5 ppm. [Section 27] 21. The process of claim 20, wherein after metal oxide treatment, the total metal impurity content is less than 10 ppm. [Section 28] 21. The process of claim 20, wherein the filtration occurs in a pyrolysis facility and the metal oxide processing occurs in a refinery that includes an FCC unit. [Section 29] 21. The process of claim 20, wherein the waste plastics selected in (a) are from plastic classification groups 2, 4, and / or 5. [Section 30] 21. The process of claim 20, further comprising producing sustainable fuel products at a refinery and blending the products to produce gasoline, jet and / or diesel products. [Section 31] 31. The process of claim 30, wherein a jet fuel product is produced.

Claims

1. A continuous process for converting waste plastics into recycling for polyethylene polymerization, comprising: (a) selecting waste plastics comprising polyethylene and / or polypropylene; (b) passing the waste plastic from (a) through a pyrolysis reactor to thermally decompose at least a portion of the polyolefin waste and produce a pyrolyzed effluent; (c) separating the pyrolyzed effluent into off-gas, pyrolysis oils (including naphtha, diesel and heavy fractions), and char; (d) passing the pyrolysis oil from (c) through a filtration / metal oxide treatment; (e) recovering the treated pyrolysis oil and passing it through a refinery FCC unit; (f) extracting C from the refining FCC unit; ３ recovering the olefin / paraffin mixture fraction; (g) The above C ３ passing the olefin / paraffin mixture fraction through a steam cracker for the production of ethylene; The above process comprising:

2. 2. The process of claim 1, wherein gasoline and heavy fractions are recovered from a refinery FCC unit, and optionally the amount of gasoline produced by said refinery FCC unit is increased with recycled pyrolysis oil.

3. 10. The process of claim 1, wherein the ethylene produced in (g) is subsequently polymerized and a polyethylene product is prepared from the polymerized ethylene.

4. The metal oxide treatment is CaO, ZnO, MgO, NiO, MoO ３ 2. The process of claim 1, carried out with a metal oxide selected from the group consisting of alumina, silica, silica-alumina, or clay or mixtures thereof.

5. 10. The process of claim 1, wherein the filtration / metal oxide treatment is carried out in a refinery that includes a refinery FCC unit.

6. 2. The process of claim 1, wherein in (d) filtration / metal oxide treatment, solid particulate and chloride reduction is achieved, and in the refinery FCC unit, S, diene, olefin, and N reduction is achieved.

7. 2. The process of claim 1, wherein only the diesel and heavy fractions of the pyrolysis oil, or only the heavy fractions of the pyrolysis oil, are passed through filtration and metal oxide treatment.

8. 2. The process according to claim 1, wherein the treated pyrolysis oil recovered in (e) is first passed through a refined FCC feed pretreatment unit from which an effluent is recovered, and the recovered effluent is passed through a refined FCC unit, in which the filtration / metal oxide treatment in (d) achieves reduction of solid particulates and chlorides, and in which the refined FCC feed pretreatment unit achieves reduction of S, dienes, olefins and N.

9. 2. The process of claim 1, wherein the filtering utilizes a filter having pores with an average diameter of 5 microns or less.

10. 10. The process of claim 1, wherein the metal oxide treatment is carried out at a temperature greater than 200°F (93°C).

11. After filtration, the heptane insoluble content is reduced to less than 0.1 wt. %, or After metal oxide treatment, the chloride content is reduced to less than 5 ppm; or After metal oxide treatment, the total metal impurity content is less than 10 ppm; or 10. The process of claim 1, wherein the filtration occurs in a pyrolysis facility and the metal oxide processing occurs in a refinery that includes a refinery FCC unit.

12. 2. The process of claim 1, wherein the waste plastics selected in (a) are from plastic classification groups 2, 4, and / or 5.

13. 10. The process of claim 1, further comprising producing sustainable fuel products at a refinery and blending the products to produce gasoline, jet and / or diesel products, optionally producing a jet fuel product.

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