Circular Economy of Waste Plastics to Polypropylene via Petroleum Refining with Filtration of Pyrolysis Oil and Metal Oxide Treatment

Abstract

In one embodiment, a continuous process for converting waste plastics containing polyethylene and / or polypropylene into polypropylene for recycling 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 C3 olefin fraction is passed through a propylene polymerization reactor, and the C3 paraffins can be passed through a dehydrogenation unit to produce propylene for further polymerization.

Description

Technical Field

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

Background Art

[0002] Disposable plastic waste has become an increasingly important environmental problem. At present, there seem to be few options for recycling polyethylene and polypropylene waste plastics into value-added chemical products or fuel products. Currently, only a small amount of polyethylene and polypropylene are recycled via chemical recycling, and these recycled and purified polymer pellets are pyrolyzed in a pyrolysis unit to produce fuel (naphtha, diesel), feedstock for a steam cracker, or slack wax.

[0003] Processes for converting waste plastics into hydrocarbon lubricants are known. For example, U.S. Patent No. 3,845,157 discloses decomposing waste or unused polyolefins to form gaseous products such as ethylene / olefin copolymers, which are further processed to produce synthetic hydrocarbon lubricants. U.S. Patent No. 4,642,401 discloses heating pulverized polyolefin waste at a temperature of 150 - 500 °C and a pressure of 20 - 300 bar (2 - 30 MPa) to produce liquid hydrocarbons. U.S. Patent No. 5,849,964 discloses a process for depolymerizing waste plastic materials into a volatile phase and a liquid phase. The volatile phase is separated into a gas phase and a condensate. The liquid phase, condensate, and gas phase are purified into liquid fuel components using standard purification techniques. U.S. Patent No. 6,143,940 discloses a procedure for converting waste plastics into heavy wax compositions. U.S. Patent No. 6,150,577 discloses a process for converting waste plastics into lubricating oils. European Patent Application Publication No. 0620264 discloses a process for producing lubricating oils from waste or unused polyolefins, which forms a wax-like product by thermally decomposing the waste in a fluidized bed, optionally using hydrotreating, and then catalytically isomerizing and fractionating to recover the lubricating oil.

[0004] Other documents related to processes for converting waste plastics into lubricating oils 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 foregoing patent documents are hereby incorporated by reference in their entirety.

[0005] Current methods of chemical recycling via pyrolysis cannot have a significant impact on the plastics industry. Current pyrolysis operations produce poor-quality fuel components (products in the naphtha and diesel ranges), but the quantity is so small that these products can be blended into the fuel supply. However, to address environmental concerns, such simple blending cannot continue in order to recycle very large quantities of waste polyethylene and waste polypropylene. The as-produced products from the pyrolysis unit are of such poor quality that they cannot be blended in large quantities (e.g., 5 - 20 vol% blend) into transportation fuels.

[0006] To industrially recycle disposable plastics in large quantities and reduce their environmental impact, a more robust process is needed. In this improved process, a "circular economy" for waste polyethylene and waste polypropylene plastics should be established, and used waste plastics need to be effectively recycled as starting materials for polymers and high-value by-products.

Summary of the Invention

[0007] Provided is a continuous process for converting waste plastics into recycling for polypropylene polymerization. This 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] Integrating this process into an oil refinery is an important aspect of this process, and it can achieve a circular economy with disposable waste plastics such as polyethylene or polypropylene. In this way, pyrolysis oil (e.g., the entire liquid fraction from the pyrolysis unit) can be passed through a refining FCC unit, from which a liquid petroleum olefin stream can be recovered. The C3 olefin stream from the FCC unit can be separated and passed through a propylene polymerization unit.

[0009] Another important aspect of this process is to upgrade 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 a refining unit such as an FCC unit. This is because these contaminants can deactivate the refining catalyst, cause unit fouling, or cause corrosion in processing units typically made of carbon steel. The use of fine filtration followed by metal oxide treatment has been found to be an effective treatment process for upgrading pyrolysis products for safe processing in a refining unit. By using fine filtration and metal oxide treatment and integrating with a refinery, large-scale and efficient recycling becomes possible.

[0010] In another embodiment, a continuous process is provided for converting waste plastics containing polyethylene and polypropylene into recycle for polypropylene polymerization. This process involves selecting waste plastics containing 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 to produce a pyrolyzed effluent. The pyrolyzed 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 microfiltered and then treated with metal oxides. The resulting treated pyrolysis product is safely passed through a refined FCC unit. The FCC unit converts the treated pyrolysis oil product into FCC hydrocarbon products. The FCC products are sent to the FCC unit separation section, where off-gas, C3, C4, FCC gasoline, and heavy fractions are produced. C4 is separated from the mixture, leaving a C3 olefin / paraffin mixture, which is separated into C3 paraffin and C3 olefin fractions. The C3 olefins are passed through a propylene polymerization reactor. Optionally, the C3 paraffins are passed through a dehydrogenation unit to produce propylene for subsequent polymerization into polypropylene.

[0011] The recovered FCC gasoline is sent to the gasoline blend pool. The heavy portion of the hydrocarbons from the FCC unit distillation is sent to an appropriate refining unit to upgrade to clean gasoline and diesel. The recovered C4 LPG fraction contains butane and butene 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 before the FCC unit. This unit is effective in removing sulfur, nitrogen, phosphorus, silica, dienes, and metals that can damage the catalyst performance of the FCC unit. Also, this unit hydrogenates aromatic compounds and improves the liquid yield of the FCC unit.

[0013] Among other factors, it has been found that by adding a refinery operation, waste pyrolysis oil and waste pyrolysis wax can be upgraded to high-value products such as gasoline, diesel, and base oil. Also, by adding a refinery operation, it has been found that clean naphtha (C5-C8) or C4 or C3 can be efficiently and effectively produced from waste pyrolysis oil, enabling the production of ultimate polypropylene polymers. In the entire process from recycled plastics to polypropylene products with product quality equivalent to that of virgin polymers, the economy of plastics is realized. Furthermore, it has been discovered that the most effective process is achieved by upgrading pyrolysis oil before integrating it into the refinery operation. It has been found that using a combination of microfiltration and metal oxide treatment is the most effective. Such filtration / metal oxide treatment of pyrolysis oil enables the safe recycling of larger amounts of waste plastics.

Brief Description of the Drawings

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

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

[0016] [Figure 3] Figure 3 shows this process for establishing a circular economy from waste plastics to recycled polypropylene according to this process including the filtration / metal oxide treatment of pyrolysis oil carried out at a refinery.

[0017] [Figure 4] Figure 4 shows the type classification of plastics regarding the recycling of waste plastics.

DETAILED DESCRIPTION OF THE INVENTION

[0018] In this process, a method for establishing a circular economy is provided by recycling waste polyethylene and / or waste polypropylene into virgin polypropylene and combining separate industrial processes. Most of the polyethylene and polypropylene polymers are used for disposable plastics and discarded after use. This disposable plastic waste has become an increasingly important environmental problem. At present, there seem to be few options for recycling waste plastics of polyethylene and polypropylene into value-added chemical substances or fuel products. Currently, only a small amount of polyethylene / polypropylene is recycled through chemical recycling, and these recycled and purified polymer pellets are pyrolyzed in a pyrolysis unit to produce fuel (naphtha, diesel), feedstock for a steam cracker, or slack wax.

[0019] Polypropylene is the second most widely produced general-purpose plastic after polyethylene, with approximately 60 million tons produced globally annually. It is widely used in various consumer and industrial products such as packaging (robust reusable containers and bottles, transparent bags or transparent containers), labels, pipes, fibers, foams, and clothing. Polypropylene has properties similar to those of polyethylene but is slightly harder, has high heat resistance, and excellent chemical resistance. Industrial manufacturing processes can be classified into gas-phase polymerization, bulk polymerization, and slurry polymerization. All of the most advanced processes use a gas-phase reaction system or a bulk reaction system at 60 - 80°C. The properties of polypropylene (densities of 0.895 and 0.92 g / cm 3) is strongly influenced by its tacticity (the orientation of the methyl groups with respect to the methyl groups of adjacent monomer units). The tacticity of polypropylene (isotactic polypropylene, syndiotactic polypropylene, atactic polypropylene) can be selected by choosing an appropriate Ziegler-Natta or metallocene organometallic catalyst.

[0020] Today, due to the inefficiencies described above, only a small portion of used polyethylene and polypropylene products are collected for recycling efforts. By using a process integrated with a refinery, this process can safely recycle larger amounts of disposable plastic waste. This process effectively establishes a circular economy.

[0021] Figure 1 shows a diagram of the pyrolysis of waste plastic fuel or wax commonly practiced in today's industry. As described above, generally, polyethylene and polypropylene waste are sorted together (1). The washed polyethylene / polypropylene waste 2 is converted into off-gas 4 and pyrolysis oil (liquid product) in the pyrolysis unit 3. The off-gas 4 from the pyrolysis unit is used as fuel for operating the pyrolysis unit. The distillation unit within the pyrolysis unit separates the pyrolysis oil to produce naphtha and diesel 5 products, which are sold on the fuel market. The heavy pyrolysis oil fraction 6 is recycled to the pyrolysis unit 3 to maximize fuel yield. The 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., it forms paraffinic wax when cooled to ambient temperature). The wax can be separated from the heavy fraction 6 and sold on the wax market.

[0022] Before introducing into the refining unit, it has been discovered that upgrading the pyrolysis oil improves the overall effectiveness and safety of the process. More specifically, important substances that need to be removed from the pyrolysis products for co-feeding into the essential oil unit include components such as residual char, metals, and chlorides. Pyrolysis products containing these impurities cannot be supplied in large quantities to the refining unit. This is because char and inorganic solids cause blockage of the unit, metals permanently deactivate the refining catalyst, and chlorides cause corrosion of the processing equipment. Reduction of chloride impurities is particularly important before supplying to the refining unit. This is because chlorides can cause severe corrosion to the bare carbon steel that constitutes most refining units. Corrosion caused by chlorides is particularly accelerated at high temperatures above 500°F (260°C) at which most refining units operate.

[0023] The pyrolysis product treatment of this process can be efficiently carried out in combination with the pyrolysis unit during the production of pyrolysis oil and wax. Alternatively, the treatment can also be carried out at the refinery before supplying the pyrolysis oil and wax to the refining unit. This process of microfiltration and metal oxide treatment does not reduce S impurities, N impurities, olefin, and diene content either. In the current process for establishing circular economy, the conversion of these compounds is effectively achieved by refining units such as fluid catalytic cracking (FCC) units, FCC feed pretreatment units, refinery crude units, cokers, distillate hydrotreating units, or hydrocracking units.

[0024] This process converts large quantities of waste polyethylene and / or polypropylene plastics that have been pyrolyzed by integrating the pyrolysis product stream of waste polymers into the oil refinery operation. The resulting process produces raw materials for polymers (naphtha or C3-C4 or C3 only for propylene polymerization units), as well as high-quality gasoline, jet, and diesel fuels, and / or high-quality base oils.

[0025] Generally, this process provides a circular economy for polypropylene plants. Polypropylene is produced through the polymerization of pure propylene.

[0026] By adding purification operations to upgrade waste pyrolysis oil to high-value products (gasoline and diesel, base oil) and to produce clean LPG for the production of the ultimate polypropylene polymer, a plus economy can be created throughout the process from recycled plastics to polypropylene products with quality equivalent to that of virgin polymers.

[0027] The pyrolysis unit produces low-quality products containing contaminants such as calcium, magnesium, chlorides, nitrogen, sulfur, phosphorus, silicon, dienes, and heavy components, and these products cannot be used in large quantities for blending transportation fuels. It has been discovered that by passing these products through a purification unit, the contaminants can be captured in a pretreatment unit and their adverse effects mitigated. The fuel components can be further upgraded in a suitable purification unit with a chemical conversion process, and the final transportation fuels produced by the integrated process are of higher quality and can meet the fuel quality requirements. In this process, wax is upgraded to valuable gasoline, diesel, and base oil. The integrated process produces a much cleaner C3 stream for propylene production and polypropylene manufacturing. These mass productions according to these specifications enable a realizable "circular economy" of recycled plastics.

[0028] However, it has been discovered that upgrading of pyrolysis products is still necessary before the stream is integrated with the purification unit, which is an important aspect of this process. Waste plastic pyrolysis oil and wax contain multiple contaminants that cannot be fed in large quantities to the purification unit because they can deactivate the purification catalyst, cause fouling of the unit, or cause severe corrosion in the processing units generally made of bare carbon steel.

[0029] Figure 2 shows a series of processes of microfiltration and metal oxide treatment. In Figure 2, the washed polyethylene / polypropylene waste 22 is passed through a pyrolysis reactor 23 to thermally decompose at least a part of the polyolefin waste and generate a pyrolyzed effluent. The 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. The off-gas 24 can be used as fuel for operating the pyrolysis unit. The liquid product from the pyrolyzed effluent is then passed through a microfiltration unit 27-1. Optionally, the produced pyrolysis wax can also be sent for microfiltration (and metal oxide treatment).

[0030] The microfiltration unit removes solids in the pyrolysis oil, especially inorganic solids resulting from char and contamination generated by the pyrolysis process. Metals often exist as inorganic solids in the form of metal chlorides, metals or metal oxides. Thus, the microfiltration process reduces contaminants derived from char, metals, metal oxides, and metal chlorides. It is necessary to use a very fine filter medium, preferably a filter with a nominal filtration accuracy of less than 5 microns, more preferably less than 2.5 microns, and most preferably less than 1 micron. A plurality of filter units with filter elements of different sizes may be used in series. These filter media (filter materials) are well-known in industrial applications. The filter media must be able to withstand the temperature of the pyrolysis oil and especially the chemical nature of the contaminants. The residual solid content can be measured, for example, by the heptane insolubility test, ASTM D-3279 method. The content of heptane-insoluble matter needs to be reduced to less than 0.5 wt%, preferably less than 0.1%.

[0031] After filtration, the filtered liquid effluent is passed through a metal oxide treatment 27-2. The metal oxide treatment removes organic chlorides and metals from the filtered pyrolysis oil. The removal of chlorides and impurities is more effective when the metal oxide treatment temperature exceeds 200°F (93°C), preferably exceeds 300°F (149°C), and most preferably exceeds 400°F (204°C). The preferred pressure range is from atmospheric pressure to 1000 psig, preferably from 0 psig to 600 psig. Optionally, H2 gas can be added to the treatment process to reduce fouling of the metal oxide and improve performance. The preferred amount of H2 gas flow rate ranges from 0 to 2000 scf / bbl of pyrolysis oil. Metal oxides with a large 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 composed of Mg, Ca, Al, Zn, or combinations thereof are particularly effective for the removal of 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 for the removal of residual metals, but can also remove other contaminants such as chlorides, 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.

[0032] The treated effluent can then be cooled in a heat exchanger 62 and the entire treated liquid product (naphtha, distillate, and heavy fraction) 25 can be sent to a purification unit 63.

[0033] The pyrolysis unit can be located near the waste plastic collection site, which can be located away from the refinery, near the refinery, or within the refinery. When the pyrolysis unit is located away from the refinery, the pyrolysis oil (naphtha / diesel and heavy oil) can be transferred to the refinery by truck, barge, railway vehicle, or pipeline. However, it is preferred that the pyrolysis unit be located within the waste plastic collection site or within the refinery.

[0034] In Figure 3, microfiltration and metal oxide treatment 27 are carried out in the pyrolysis facility. The entire liquid pyrolysis product 25 from the pyrolysis unit 23 is sent to the filtration unit, followed by oxide treatment. The hot pyrolysis liquid is preferably filtered and treated with metal oxide before being completely cooled to ambient temperature for storage and / or transfer. Therefore, filtration and metal oxide treatment are preferably carried out in the pyrolysis facility after the entire liquid product 25 has been recovered, or simultaneously with the collection process of the entire liquid product. The treated liquid product can then be transferred to the refinery. In another embodiment, the entire liquid product 25 can be transferred to the refinery, and microfiltration and metal oxide treatment 27 are completed at the refinery.

[0035] The preferred starting material for this process is sorted waste plastic mainly containing polyethylene and polypropylene (plastic recycling classification types 2, 4, and 5). The pre-sorted waste plastic is washed, shredded or pelletized, supplied to the pyrolysis unit, and pyrolyzed. Figure 4 shows the plastic type classification for the recycling of waste plastic. Classification types 2, 4, and 5 are high-density polyethylene, low-density polyethylene, and polypropylene, respectively. The waste plastics of polyethylene and polypropylene can be used in any combination. In this process, it is preferred to use at least some waste plastic of polyethylene.

[0036] To minimize contaminants such as N, Cl, and S, it is very important to properly sort waste plastics. Plastic waste containing polyethylene terephthalate (plastic recycling classification type 1), polyvinyl chloride (plastic recycling classification type 3), and other polymers (plastic recycling classification type 7) should be sorted to less than 5%, preferably less than 1%, and most preferably less than 0.1%. This process can tolerate a moderate amount of polystyrene (plastic recycling classification type 6). Waste polystyrene should be sorted to less than 30%, preferably less than 20%, and most preferably less than 5%.

[0037] When waste plastics are washed, metal contaminants such as sodium, calcium, magnesium, and aluminum, as well as non-metal contaminants from other waste sources, are removed. Non-metal 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, and iodides. Residual metals, non-metal contaminants, and halides need to be removed to less than 50 ppm, preferably less than 30 ppm, and most preferably less than 5 ppm.

[0038] 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 mainly containing 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. Patent No. 4,642,401). Furthermore, it has been found that the yield of the desired product can be controlled by adjusting the pressure downward (see, for example, U.S. Patent No. 6,150,577). Thus, in some embodiments where such control is desired, the pyrolysis pressure is less than atmospheric pressure.

[0039] It has been discovered that the use of microfiltration followed by the use of metal oxide treatment is essential to achieve a feed stream that can be efficiently passed through a refinery without causing problems such as corrosion, clogging, or catalyst deactivation. Microfiltration means a filter with a pore size of 5.0 microns or less, preferably 1.0 micron or less, and in one embodiment about 0.5 microns. This treatment allows a large amount of waste plastic pyrolysis liquid product to be passed through a refinery, enabling the most effective recycling process to be realized.

[0040] Figure 3 shows the integrated process and depicts an integrated refining operation involving pyrolysis, filtration, and metal oxide treatment of waste plastics, as well as recycling for efficient polypropylene production. The same numbers in Figures 2 and 3 refer to the same types of units and product flows. The washed waste plastic 22 is converted in the pyrolysis unit 23 into off-gas 24 and pyrolysis oil (liquid product). The off-gas 24 from the pyrolysis unit can be used as fuel for operating the pyrolysis unit 23. The pyrolysis oil (the entire liquid product 25) contains naphtha, diesel distillate, and heavy distillate. After completion of the pyrolysis step, char 26 is removed from the pyrolysis unit 23. The entire pyrolysis oil (naphtha, distillate, and heavy fraction) 25 is passed through filtration and metal oxide treatment 27 and then 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.

[0041] The fluid catalytic cracking (FCC) process is widely used in the refining industry to convert atmospheric gas oil, vacuum gas oil, atmospheric residue, and heavy fractions recovered from other refining operations into high-octane gasoline, light fuel oil, heavy fuel oil, olefin-rich light gas (LPG), and coke. FCC uses a highly active zeolite catalyst to decompose heavy hydrocarbon molecules at a reactor temperature of 950 - 990°F (510 - 532°C) in the riser with a short contact time of less than a few minutes. The LPG stream containing olefins (propylene, butylene) is usually upgraded to produce alkylate gasoline or for use in the manufacture of chemical products. Conventional FCC units are used.

[0042] When pyrolysis liquid oil combined with petroleum-derived oil is decomposed in an FCC unit, liquefied petroleum gas (LPG) olefin streams 31 and 32, as well as gasoline 29 and heavy fraction 30 are produced. C2 - Offgas 33 is also produced.

[0043] Refineries generally have a unique hydrocarbon supply from petroleum-derived oil flowing through the refining unit. The volume of the pyrolysis oil stream generated from the pyrolysis of waste plastics and flowing into the refining unit can constitute any practical or accommodatable volume percentage (vol%) of the total flow into the refining unit. Generally, 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., the refining flow rate and the pyrolysis flow rate) for practical reasons. In one embodiment, the flow rate of pyrolysis oil is an amount up to about 20 vol% of the total flow rate. In another embodiment, the flow rate of pyrolysis oil is an amount up to about 10 vol% of the total flow rate. About 20 vol% has been found to be a very practical amount in terms of the impact on the refinery, while providing excellent results and being an accommodatable amount. Of course, the amount of pyrolysis oil and wax generated from pyrolysis can be controlled so that the fractions passed through the refining unit provide the desired volume percentage of the flow rate.

[0044] The LPG olefin stream 31 is a C3 liquefied petroleum gas (LPG) fraction containing propane and propylene. The C3 stream of the propane and propylene mixture is separated by a propane / propylene splitter (PP splitter) 34 to produce pure streams of propylene 35 and propane 36. The propylene stream 35 can be directly fed to a polypropylene polymerization unit 40.

[0045] Pure propane can be fed to a propane dehydrogenation unit 37 to produce propylene 35, and then finally, polypropylene can be produced in a propylene polymerization unit 40. The dehydrogenation of propane is widely practiced in the industry to produce propylene. The reaction is endothermic and the conversion is maintained by a multi-stage reactor and inter-stage heaters. The unit is typically operated at high temperature (>900°F) and low pressure (<50 psig) in the presence of a noble metal (Pt) catalyst. A propylene / propane mixture of about 85% purity is produced by a multi-stage process. This stream is sent to a propane-propylene (P-P) splitter, which is a high-efficiency distillation column. This splitter produces a pure propylene stream with a purity of 99.5 - 99.8%.

[0046] The LPG olefin stream 32 is a C4 liquefied petroleum gas (LPG) fraction containing butane and butene. This fraction can be sent to an alkylation unit (not shown) in a refinery or can be upgraded or blended into gasoline.

[0047] The FCC gasoline 29 can be sent to a gasoline blend pool. The heavy portion 30 recovered from the FCC unit 28 is sent to an appropriate purification unit 38 (such as a hydrotreating, hydrocracking, and / or coker unit) to upgrade it to clean gasoline and diesel 39. The C4 stream 32 can be sent to a gasoline blend pool or can be further upgraded to cleaner gasoline (through processes such as alkylation or C4 olefin dimerization or ether synthesis).

[0048] The polypropylene polymer produced in the propylene polymerization unit 40 can then be manufactured into consumer products 41.

[0049] The propylene polymerization unit is preferably located near the refinery so that the raw materials (propane and propylene) can be transferred via a pipeline. In the case of a petrochemical plant located far from the refinery, the raw materials can be delivered via trucks, barges, railroad cars, or pipelines.

[0050] In another embodiment, the treated pyrolysis oil is first sent to an FCC feed pretreatment unit (not shown) before 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 feedstock using a stream of H2 gas 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 would impair the catalyst performance of the FCC unit. Also, this unit hydrogenates aromatic compounds and improves the liquid yield of the FCC unit.

[0051] The carbon going in and out in the purification operation is "transparent", which means that not all molecules from the waste plastics circulate back to the polyolefin plant and become the exact olefin products. However, since the net "green" carbon going in and out of the refinery is positive, it is considered a "credit". These integrated processes will significantly reduce the amount of unused feedstock required for the polyethylene plant.

[0052] The merits of circular economy and effective and efficient recycling campaigns are realized by this integrated process. Through the use of microfiltration and metal oxide treatment, a larger amount of feedstock can be safely and efficiently circulated through the purification plant.

[0053] The following non-limiting examples illustrate the process and its advantages.

Example

[0054] [Example 1] Characteristics of Pyrolysis Oil and Wax from Commercial Sources

[0055] Samples of pyrolysis oil and wax were obtained from commercial sources. Their characteristics are summarized in Table 1. These pyrolysis samples were prepared from waste plastics mainly containing polyethylene and polypropylene through pyrolysis in a pyrolysis reactor at about 400 - 600 °C and near atmospheric pressure without adding gas or catalyst. The pyrolysis unit typically produces gas, liquid oil products, optionally wax products, and char. The overhead gas stream containing the thermally decomposed hydrocarbons from the pyrolysis unit 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 main product of the pyrolysis unit. Some pyrolysis units also produce pyrolysis wax as another product in addition to pyrolysis oil.

Table 1

[0056] The ASTM D4052 method was used for specific gravity determination. The simulated boiling point distribution curve was obtained using the ASTM D2887 method. The Carlo-Erba analysis of carbon and hydrogen was performed based on the ASTM D5291 method. The bromine number measurement was carried out based on the ASTM D1159 method. The hydrocarbon type analysis was performed using a high-resolution magnetic mass spectrometer by scanning the magnet from 40 to 500 Daltons. Total sulfur was determined using XRF in accordance with the ASTM D2622 method. Nitrogen was determined using chemiluminescence detection by the modified ASTM D5762 method. The total chloride content was typically measured using combustion ion chromatography (CIC) equipment by the modified ASTM 7359 method. The oxygen content in the boiling range of naphtha and distillate was estimated using GC with an electron ionization detector in the m / Z range of 29 to 500 for GC / MS measurement. Trace metal and non-metal elements in the oil were determined using inductively coupled plasma atomic emission spectrometry (ICP-AES).

[0057] In the industrial pyrolysis process of selected plastics mainly supplied from polyethylene and polypropylene wastes, a high-quality hydrocarbon stream with a specific gravity in the range of 0.7 to 0.9 and a boiling range of 18 to 1100°F was produced, as in the case of pyrolysis oil or pyrolysis wax.

[0058] The pyrolysis products are fairly pure hydrocarbons mainly composed of carbon and hydrogen. The molar ratio of hydrogen to carbon varies up to nearly 1.7 - 2.0. The bromine number ranges from 14 to 60, indicating varying degrees of unsaturation due to olefins and aromatic compounds. The aromatic content ranges from 5 to 23 volume %, with more aromatic compounds being produced in units with more severe pyrolysis conditions. Depending on the process conditions of the pyrolysis unit, the pyrolysis products exhibit a paraffin content in the range of around 20 vol% to around 50 vol%. The pyrolysis products contain a significant amount of olefins. Sample A and Sample B are pyrolysis oils produced under more severe conditions such as higher pyrolysis temperatures and / or longer residence times, with a high aromatic component and a low paraffin component. As a result, the H / C molar ratio is about 1.7 and the bromine number is as high as 50 - 60. Sample C and Sample D are produced under less severe conditions, and their pyrolysis oils are more paraffinic. As a result, the H / C molar ratio is close to 2.0 and the bromine number is about 40. Sample E (pyrolysis wax) consists mostly of paraffinic saturated hydrocarbons and contains a significant amount of straight-chain hydrocarbons (in contrast to branched hydrocarbons), with a bromine number of only 14.

[0059] [Example 2] Micro Filtration for Removing Contaminants and Solids in Pyrolysis Oil

[0060] Pyrolysis oil or wax products contain residual solids and other impurities that can potentially affect the performance of the refinery's conversion units. 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.

[0061] The residual solid content can be measured by the heptane insolubility test (ASTM D - 3279 method). Fluorescent X-ray (XRF) method was used for chloride analysis.

Table 2

[0062] In this study, it was found that the pore size of the filter is important for impurity removal. When using a 25-micron filter, the filter paper became clogged and the filtration of the three pyrolysis oils could not be completed. When using a 0.7-micron filter, the content of heptane-insoluble solids decreased by more than 90% through filtration. In this study, it was shown that filtration using a filter with a small pore size (for example, a filter of 1.0 micron or less such as a 0.7-micron filter) is effective for removing residual solids. Surprisingly, filtration effectively removed chloride impurities (Examples 2-1 to 2-4) except for one case (Example 2-5). This data suggests that the pyrolysis oil products contain various amounts of inorganic chloride species and that the impurity level can be significantly reduced by filtration. However, in Example 2-5, no decrease in chloride species was observed. This suggests that some chloride species are essentially organic and that further treatment beyond the filtration process is required.

[0063] [Example 3] Pretreatment of Pyrolysis Oil by Filtration Followed by Metal Oxide Treatment with CaO / ZnO / Clay

[0064] 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 a filtered oil (Sample F-1). As shown in Table 3, the general raw material properties and impurities of these samples were analyzed.

Table 3

[0065] The continuous filtration unit equipped with a nominal 0.5-micron filter cartridge was effective, reducing the content of heptane-insoluble solids by 87% and producing a filtered oil (Sample F-1) with 314 residual heptane-insoluble solids. Considerable amounts of other impurities such as nitrogen, chloride, iron, phosphorus, and silicon were also removed by filtration.

[0066] Sample F-1 was further processed by passing it through a fixed-bed reactor containing a metal oxide adsorbent made of CaO / ZnO / clay. The metal oxide treatment experiment was carried out with a reactor pressure of 600 psig and a flow rate of 1 LHSV while varying the temperature from 200 to 400°F. 1500 SCF / BBL of hydrogen was fed into the reactor together with the oil. The results are summarized in Table 4 below. [Table 4]

[0067] The metal oxide treatment process removed a significant amount of metals (Fe) and other non-metals (N, Cl, P, Si) that may have an adverse effect on the performance of the conversion unit in the refinery. The metal oxide containing CaO and ZnO was particularly effective in removing chlorides and iron. The removal was more efficient at high temperatures.

[0068] [Example 4] Pretreatment of pyrolysis oil by filtration followed by metal oxide treatment using NiO / MoO3 / PO4 / alumina

[0069] 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 a filtered oil (Sample G-1). As shown in Table 5, the general feedstock properties and impurities of these samples were analyzed. [Table 5]

[0070] The data in Table 5 shows that a continuous filtration unit equipped with a nominal 0.5 micron filter cartridge is effective in reducing impurities such as nitrogen, chloride, calcium, chromium, iron, magnesium, and silicon. However, filtration did not remove sulfur and phosphorus impurities.

[0071] Sample G-1 was further processed by passing it through a fixed-bed reactor containing a metal oxide adsorbent made of NiO / MoO3 / PO4 / alumina. The metal oxide treatment experiment was carried out with a reactor pressure of 400 psig and a flow rate of 1 LHSV, while varying the temperature from 500 to 550°F. Hydrogen at 1500 SCF / BBL was fed into the reactor together with the oil. The results are summarized in Table 6 below. [Table 6]

[0072] The metal oxide treatment process removed a significant amount of metals (Fe, Ca, Cr, Mg) and other non-metals (N, Cl, P, Si) that could potentially affect the performance of the conversion unit in the refinery. The MoO3- and NiO-containing metal oxides were particularly effective in removing metals at around 500 to 550°F.

[0073] Examples 5 to 8 below show the evaluation of waste plastic pyrolysis oil as a transportation fuel.

[0074] [Example 5] Fractionation of Pyrolysis Oil for Evaluation as a Transportation Fuel

[0075] Sample D was distilled to produce multiple fractions of hydrocarbons, namely, a gasoline (350°F - ) fraction, a jet (350 - 572°F) fraction, a diesel (572 - 700°F) fraction, and a heavy (700°F + ) fraction. Table 7 summarizes the boiling point distribution and impurity distribution of each fraction of the distillation product. [Table 7]

[0076] [Example 6] Evaluation of a Fraction of Pyrolysis Oil for Gasoline Fuel

[0077] For Sample H (a fraction of pyrolysis oil within the boiling range of gasoline fuel), the usability as a gasoline fuel was evaluated. The carbon number range of Sample H is C5 - C12, which is typical for gasoline fuel.

[0078] Since the pyrolysis oil is olefinic, the oxidation stability (ASTM D525) and gum formation tendency (ASTM D381) were identified as the most important properties to be investigated. The Research Octane Number (RON) and Motor Octane Number (MON) are also important properties for engine performance. The values of RON and MON were estimated from a detailed GC analysis of the hydrocarbons. [Table 8]

[0079] Sample H (a fraction of pyrolysis oil in the boiling range of gasoline fuel) has poor quality and cannot be used alone as a gasoline fuel for automobiles. The gasoline fraction from the pyrolysis oil showed very low oxidation stability in that Sample H failed after only 90 minutes compared to the target stability of over 1440 minutes. The pyrolysis gasoline exceeds the target of 4 mg / 100 mL for wash gum, indicating a strong tendency to form gum. The pyrolysis gasoline has a lower octane number compared to the reference gasoline. Premium unleaded gasoline was used as the reference gasoline.

[0080] The possibility of blending a limited amount of the pyrolysis gasoline fraction with the reference gasoline was also investigated. This investigation showed that it might be possible to blend up to 15 vol% of Sample H with the refined gasoline while achieving the fuel property targets. By integrating the pyrolysis gasoline product with the refined fuel, the overall quality of the product can be maintained.

[0081] These results indicate that the as-produced gasoline fraction of the pyrolysis oil has limited usefulness as a gasoline fuel. To convert the gasoline fraction of the pyrolysis oil into hydrocarbons that meet the gasoline fuel property targets, upgrading in a refining unit is necessary.

[0082] [Example 7] Evaluation of a Fraction of Pyrolysis Oil for Jet Fuel

[0083] For Sample I (a fraction of pyrolysis oil in the boiling range of jet fuel), its usability as jet fuel was evaluated. The carbon number range of Sample I is C9 - C18, which is typical for jet fuel.

[0084] Since pyrolysis oil is olefinic, the Jet Fuel Thermal Oxidation Test (D3241) was regarded as an important test. Sample I, which is the pyrolysis oil jet fraction as it is, had an oxidation stability of only 36 minutes, indicating that the pure pyrolysis jet fraction is not suitable for use as jet fuel.

[0085] A blend of 5 volume% of the pyrolysis jet fraction (Sample I) with jet fuel produced at a refinery was prepared. As shown in Table 9, this blend still failed the oxidation test for jet fuel. [Table 9]

[0086] These results indicate that the as - produced jet fraction of pyrolysis oil is completely unsuitable for jet fuel, showing that upgrading in a refining unit is necessary to convert this jet fraction of pyrolysis oil into hydrocarbons that meet the characteristic targets of jet fuel.

[0087] [Example 8] Evaluation of a Fraction of Pyrolysis Oil for Diesel Fuel

[0088] For Sample J (a fraction of pyrolysis oil in the boiling range of diesel fuel), its usability as diesel fuel was evaluated. The carbon number range of Sample J is C14 - C24, which is typical for diesel fuel.

[0089] Sample J contains a significant amount of normal hydrocarbons. Since normal hydrocarbons tend to exhibit waxy characteristics, low - temperature flow properties such as pour point (ASTM D5950 - 14) and cloud point (ASTM D5773) were regarded as the most important tests.

[0090] 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]

[0091] 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.

[0092] [Example 9] Co-processing of pyrolysis products into FCC units

[0093] 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.

[0094] 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).

[0095] [Example 10] Conversion of Pyrolysis Oil in FCC

[0096] To investigate the effect of coprocessing of pyrolysis oil from waste plastics 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 volume% blend of pyrolysis oil with VGO and pure pyrolysis oil was compared with that of a pure VGO feedstock.

[0097] The FCC experiments were conducted 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-fluidized reactor using N2 as the fluidizing gas. The catalytic cracking experiments were carried out at atmospheric pressure and a reactor temperature of 900°F. By varying the amount of catalyst, the catalyst / oil ratio was changed between 5 and 8. The gas products were collected and analyzed using a purified gas analysis unit (RGA) equipped with a GC with an FID detector. In-situ regeneration of the spent catalyst was carried out in the presence of air at 1300°F, and the coke yield was determined by passing the regeneration flue gas through a LECO. The liquid products were weighed and analyzed by GC for simulated distillation (D2887) and C5 - composition analysis. By material balance, the yields 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 + ) were determined. The results are summarized in Table 11 below.

Table 11

[0098] The results in Table 11 indicate that co-feeding up to 20% by volume of pyrolysis oil only brings about very slight changes in the performance of the FCC unit, showing that co-processing up to 20% of pyrolysis oil can be easily carried out. With a 20% by volume blend of Sample A or Sample C, the yields of coke and dry gas decreased slightly, the yield of gasoline increased slightly, and the yields of LCO and HCO decreased slightly. These are favorable in most situations. Since the pyrolysis oil is paraffinic, the octane number decreased by about 3 - 5 with a 20% blend of Sample A or Sample C. Due to the operational flexibility of the refinery, these negative octane number differences can be compensated for by adjusting the blend or the supply position.

[0099] The FCC unit decomposes pyrolysis oil into hydrocarbon fuels within the fuel range, reduces impurities, and isomerizes n-paraffins to isoparaffins. Due to all these chemical properties, the fuel characteristics of pyrolysis oil and wax are improved. By co-feeding pyrolysis oil with a zeolite catalyst through the FCC process unit, the oxygen and nitrogen impurities within the fuel range were significantly reduced, with nitrogen (N) decreasing from approximately 300 - 1400 ppm to about 30 ppm and oxygen (O) decreasing from approximately 250 - 540 ppm to about 60 - 80 ppm. The hydrocarbon composition of all these co-fed products is well within the range of typical FCC gasoline.

[0100] In the FCC operation with 100% pyrolysis oil, a significant negative octane number difference (the negative difference was about 13 - 14) was shown. This indicates that co-processing of pyrolysis oil is more preferable than processing pure 100% pyrolysis oil.

[0101] [Example 11] Co-processing of Pyrolysis Wax in FCC

[0102] To investigate the impact of co-processing of waste plastic pyrolysis wax in FCC, a series of laboratory tests were carried out using Sample E and VGO. Similar to Example 10, the FCC performance of a 20% blend of pyrolysis wax with VGO and pure pyrolysis wax was compared with that of a pure VGO feedstock. The results are summarized in Table 12 below. [Table 12]

[0103] The results in Table 12 show that co-feed of up to 20 vol% of pyrolysis wax only brings about very slight changes in the performance of the FCC unit, indicating that co-processing of up to 20% of pyrolysis wax is easily feasible. With a 20 vol% blend of Sample E, the yields of coke and dry gas hardly changed, the yield of LPG olefins increased significantly, the yield of gasoline increased slightly, and LCO and HCO decreased slightly. These are favorable in most situations. Since the pyrolysis oil wax is paraffinic, the octane number decreased slightly by 1.5 with a 20% blend of Sample E. Due to the flexibility of the refinery blend, this negative octane number can be easily compensated for by a slight blend adjustment.

[0104] In the FCC operation with 100% pyrolysis wax, the conversion rate increased significantly, showing a negative octane number (the negative number was 6). This indicates that co-processing of pyrolysis wax is more preferable than processing 100% pyrolysis wax.

[0105] [Example 12] Recycling of C3 for the isolation or production of propylene and subsequent production of polypropylene resin and consumer products made of polypropylene

[0106] As shown in Examples 10 and 11, co-feeding the pyrolysis products to the FCC unit generates a significant amount of C3LPG vapor containing recycled components. This C3 stream is a suitable feedstock for supplying to the polymerization unit to produce polypropylene polymers containing recycled components. To achieve this, C3LPG vapor containing propane and propylene is captured and fed to a propane / propylene (P / P) splitter to separate pure propylene vapor (>99 mol%) and supply it to the propylene polymerization unit. The propane from the P / P splitter may be dehydrogenated for the polymerization unit to produce additional propylene.

[0107] Polypropylene resins containing materials derived from recycled polyethylene / polypropylene are of high quality and indistinguishable from virgin polypropylene resins made from completely virgin petroleum resources. Polypropylene resins containing this recycled material can be further processed to produce various polypropylene products that meet the needs of consumer products. These consumer polypropylene products contain chemically recycled circular polymers, but the quality of these products is indistinguishable from those made from completely virgin polypropylene polymers. These chemically recycled polymer products are different from mechanically recycled polymer products, which are of inferior quality compared to polymer products made from virgin polymers.

[0108] [Example 13] Production of high-quality gasoline, jet, and diesel products containing recycled components

[0109] As shown in Examples 10 and 11, co-feeding pyrolysis oil and / or wax to the FCC unit produces a significant amount of C3-C5 olefins containing recycled components, as well as gasoline, jet, and diesel products. The C4 stream only or the C4-C5 stream containing recycled olefins is separated from the FCC light end recovery unit and fed to the alkylation unit. The reaction of LPG olefins with isobutane in the alkylation reactor produces n-butane and alkylate gasoline containing recycled components. Alkylate gasoline and n-butane are valuable blend components for gasoline. The heavy fraction is further upgraded in the hydrocracking unit to produce high-quality gasoline, jet, and diesel products.

[0110] The foregoing clearly shows a new and effective method for recycling a large amount of waste plastics derived from polyethylene and polypropylene by chemical recycling via pyrolysis and subsequent co-feeding of pyrolysis products in a refinery through efficient integration. These examples also show the advantages of performing filtration / metal oxide treatment prior to the FCC unit. This integration enables the production of high-quality fuels and recyclable polymers.

[0111] As used in this disclosure, the word "comprises" or "comprising" is intended as an open-ended transitional word and means including the recited element but not necessarily excluding other unrecited 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 that excludes everything other than the recited elements, except for trace impurities.

[0112] All patents and publications referred to in this specification are incorporated herein by reference to the extent not inconsistent with this specification. It should be understood that the specific structures, functions, and operations of the above-described embodiments are not necessary for practicing the present invention and are included in the description merely to complete exemplary embodiments or multiple embodiments. Further, it should be understood that the specific structures, functions, and operations described in the above-referred patents and publications can be implemented in combination with the present invention, but they are not essential for its implementation. Therefore, 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 content of the invention according to the claims of the present application at the time of filing is as follows. [Claim 1] A continuous process for converting waste plastics into recycling for polypropylene polymerization, (a) selecting waste plastics containing polyethylene and / or polypropylene; (b) passing the waste plastics from (a) through a pyrolysis reactor to thermally decompose at least a part of the polyolefin waste and produce a pyrolyzed effluent; (c) separating the pyrolyzed effluent into off-gas, pyrolysis oil (including naphtha / diesel / heavy fraction), and char; (d) passing the pyrolysis oil from (c) through filtration / metal oxide treatment; (e) recovering the treated pyrolysis oil and passing it through a refined FCC unit; (f) recovering a liquefied petroleum C 3 olefin / paraffin mixture fraction from the FCC unit; (g) separating the C 3 paraffin and the C 3 olefin into different fractions; (h) passing the C 3 olefin through a propylene polymerization reactor; The above process. [Claim 2] C 3 The process according to claim 1, further comprising passing paraffin through a dehydrogenation unit to produce C 3 olefin and then passing the C 3 olefin through a propylene polymerization reactor. [Claim 3] The process according to claim 1, recovering gasoline and heavy fraction from a refined FCC unit. [Claim 4] The process according to claim 1, wherein the polypropylene product is prepared from polymerized propylene. [Claim 5] The process according to claim 1, wherein the amount of gasoline produced by the FCC unit is increased with recycled pyrolysis oil. [Claim 6] The process according to claim 1, wherein the waste plastics selected in (a) are from plastic classification groups 2, 4, and / or 5. [Claim 7] The process according to claim 1, using a filter having pores with an average diameter of 5 microns or less in the filtration. [Claim 8] The process according to claim 7, wherein the average diameter of the pores is less than 1 micron. [Claim 9] The metal oxide treatment according to claim 1, comprising a metal oxide selected from CaO, ZnO, MgO, NiO, MoO 3 , alumina, silica, silica-alumina, clay, or a mixture thereof. [Claim 10] The process according to claim 1, wherein the metal oxide treatment is carried out at a temperature exceeding 200°F. [Item 11] The process according to claim 1, wherein the filtration / metal oxide treatment is carried out in a refinery including an FCC unit. [Item 12] The process according to claim 1, wherein the filtration is carried out in a pyrolysis facility and the metal oxide treatment is carried out in a refinery including an FCC unit. [Item 13] The process according to claim 1, wherein after the filtration treatment, the content of heptane-insoluble matter is reduced to less than 0.1% by weight. [Item 14] The process according to claim 1, wherein after the metal oxide treatment, the chloride content is reduced to less than 5 ppm. [Item 15] The process according to claim 1, wherein after the metal oxide treatment, the total metal impurities are less than 10 ppm. [Item 16] In the filtration / metal oxide treatment of (d), reduction of solid fine particles and chlorides is achieved, and reduction of S, diene, olefin, and N is achieved by a purified FCC unit. The process according to claim 1. [Item 17] The process according to claim 1, wherein only the diesel and heavy fraction of the pyrolysis oil, or only the heavy fraction of the pyrolysis oil, is passed through the filtration and metal oxide treatment. [Item 18] The process according to claim 1, wherein the treated pyrolysis oil recovered in (e) is first passed through an FCC pretreatment unit, an effluent is recovered therefrom, and the recovered effluent is passed through a purified FCC unit. [Item 19] In the filtration / metal oxide treatment of (d), reduction of solid fine particles and chlorides is achieved, and reduction of S, diene, olefin, and N is achieved by a purified FCC feed pretreatment unit. The process according to claim 18. [Item 20] The process according to claim 18, wherein only the diesel and heavy fraction of the pyrolysis oil, or only the heavy fraction of the pyrolysis oil, is passed through the filtration and metal oxide treatment. [Item 21] A continuous process for converting waste plastic into recycling for polypropylene polymerization, (a) a step of selecting waste plastic containing polyethylene and / or polypropylene, (b) a step of passing the waste plastic from (a) through a pyrolysis reactor to thermally decompose at least a part of the polyolefin waste and generate a pyrolyzed effluent, (c) a step of separating the pyrolyzed effluent into off-gas, pyrolysis oil (including naphtha / diesel / heavy fraction), and char, (d) a step of passing the pyrolysis oil from (c) through a filtration / metal oxide treatment, (e) a step of recovering the treated pyrolysis oil and sending it to a refinery for propylene polymerization, comprising the above process. [Item 22] The process according to claim 21, wherein in said filtration, a filter having pores with an average diameter of 5 microns or less is used. [Item 23] The process according to claim 22, wherein the average diameter of said pores is less than 1 micron. [Item 24] The process according to claim 21, wherein said metal oxide treatment comprises a metal oxide selected from CaO, ZnO, MgO, alumina, silica or silica - alumina, or a mixture thereof. [Item 25] The process according to claim 21, wherein said metal oxide treatment is carried out at a temperature exceeding 200°F (93°C). [Item 26] The process according to claim 21, wherein after the filtration treatment, the content of heptane - insoluble matter is reduced to less than 0.1% by weight. [Item 27] The process according to claim 21, wherein after the metal oxide treatment, the chloride content is reduced to less than 5 ppm. [Item 28] The process according to claim 21, wherein after the metal oxide treatment, the total metal impurities are less than 10 ppm. [Item 29] The process according to claim 21, wherein the filtration is carried out in a pyrolysis facility and the metal oxide treatment is carried out in a refinery including an FCC unit. [Item 30] The process according to claim 21, wherein the waste plastic selected in (a) is from plastic classification groups 2, 4, and / or 5. [Item 31] The process according to claim 21, further comprising manufacturing a sustainable fuel product in a refinery and mixing said product to manufacture gasoline, jet and / or diesel products. [Item 32] The process according to claim 31, wherein jet fuel products are blended.

Claims

1. A continuous process for converting waste plastic into recycling for polypropylene polymerization, comprising: (a) selecting waste plastic containing polyethylene and / or polypropylene; (b) passing the waste plastic from (a) through a pyrolysis reactor to thermally decompose at least a part of the polyolefin waste and generate a pyrolyzed effluent; (c) separating the pyrolyzed effluent into off-gas, pyrolysis oil (including naphtha / diesel / heavy fraction), and char; (d) passing the pyrolysis oil from (c) through a filtration unit and then through a metal oxide treatment; (e) recovering the treated pyrolysis oil from the metal oxide treatment and passing it through a refined FCC unit; (f) recovering from the refined FCC unit a C ３ olefin and C ３ paraffin-containing mixture fraction; (g) separating the C ３ paraffin and the C ３ olefin into different fractions; (h) passing the C ３ olefin through a propylene polymerization reactor. The above process.

2. Passing C ３ paraffin through a dehydrogenation unit to produce C ３ olefin, and then further passing the C ３ olefin through a propylene polymerization reactor. The process according to claim 1.

3. Recovering gasoline and heavy fraction from the refined FCC unit. The process according to claim 1.

4. A consumer polypropylene product is prepared from polymerized propylene. The process according to claim 1.

5. The process according to claim 1, wherein the amount of gasoline produced by the purified FCC unit is increased by the treated pyrolysis oil passed through the purified FCC unit in (e). **Claim 6** The process according to claim 1, wherein the waste plastic selected in (a) is from plastic classification groups 2, 4, and / or 5. **Claim 7** The process according to claim 1, wherein in the filtration, a filter having pores with an average diameter of 5 microns or less is used. **Claim 8** The process according to claim 7, wherein the average diameter of the pores is less than 1 micron. **Claim 9** The metal oxide treatment is carried out using a metal oxide selected from CaO, ZnO, MgO, NiO, MoO ３ , alumina, silica, silica - alumina, clay or a mixture thereof, in the process according to claim 1. **Claim 10** The process according to claim 1, wherein the metal oxide treatment is carried out at a temperature exceeding 200°F (93.3°C). **Claim 11** The process according to claim 1, wherein the filtration and the metal oxide treatment are carried out at a refinery including a purified FCC unit. **Claim 12** The process according to claim 1, wherein the filtration is carried out in the pyrolysis facility and the metal oxide treatment is carried out at a refinery including a purified FCC unit. **Claim 13** The process according to claim 1, wherein after the filtration treatment, the content of heptane - insoluble matter is reduced to less than 0.1% by weight. **Claim 14** The process according to claim 1, wherein after the metal oxide treatment, the chloride content is reduced to less than 5 ppm. **Claim 15** The process according to claim 1, wherein after the metal oxide treatment, the total metal impurities are less than 10 ppm. **Claim 16** The process according to claim 1, wherein in the filtration and metal oxide treatment of (d), reduction of solid fine particles and chlorides is achieved, and reduction of S, dienes, olefins, and N is achieved by a purification FCC unit.

17. The process according to claim 1, wherein only the diesel and heavy fraction of the pyrolysis oil, or only the heavy fraction of the pyrolysis oil, is passed through the filtration and metal oxide treatment.

18. In the filtration unit, a filter having pores with an average diameter of 5 microns or less is used, and the metal oxide treatment is performed using a metal oxide selected from CaO, ZnO, MgO, NiO, MoO ３ , alumina, silica, silica - alumina, clay, or a mixture thereof.

Images