Use of blends of waste plastics and bio-based raw materials for circular economy polyethylene production

Abstract

Provided is a continuous process for converting waste plastics into recycling for polyethylene polymerization. This process includes a step of selecting waste plastics containing polyethylene and / or polypropylene, and a step of preparing a blend of the biofeedstock and the selected plastics. The amount of plastic in the blend constitutes 20 wt% or less of the blend. The blend is passed through an FCC unit. Liquefied petroleum gas LPG olefin / paraffin mixture and naphtha are recovered from the FCC unit and can be used for the production of polyethylene.

Description

Technical Field

[0001] (Cross - reference to Related Applications) This application claims priority to U.S. Provisional Application No. 63 / 359,565, filed on July 8, 2022, the entire disclosure of which is incorporated herein by reference in its entirety.

Background Art

[0002] As part of efforts to combat global warming, the industry is rapidly increasing its activities to produce chemicals and fuels from renewable resources such as bio - based raw materials.

[0003] On the other hand, the world has witnessed a very rapid growth in plastic production. According to the Plastics Europe Market Research Group, the world's plastic production volume was 335 million tons in 2016, 348 million tons in 2017, 359 million tons in 2018, and 367 million tons in 2020. According to McKinsey & Company, if the current trajectory continues, the world's plastic waste volume is estimated to reach 460 million tons per year by 2030.

[0004] 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 fuels (naphtha, diesel), feedstock for steam crackers, or slack wax. Most (over 80%) are incinerated, landfilled, or discarded.

[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 too small for these products to be blended into the fuel supply. However, to address environmental concerns, such simple blending cannot continue in order to recycle very large amounts 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 into transportation fuels.

[0006] 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 to 500 °C and a pressure of 20 to 300 bar 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, in which the waste is thermally decomposed in a fluidized bed to form a waxy product, optionally using hydrotreating, and then catalytically isomerized and fractionated to recover the lubricating oil.

[0007] 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. 2021 / 0130699, 2019 / 0161683, 2016 / 0362609, and 2016 / 0264885. The foregoing patent documents are hereby incorporated by reference in their entirety into this specification.

[0008] Worldwide, the recycling and upcycling of plastic waste has attracted great attention for resource and environmental conservation. The mechanical recycling of plastic waste is quite limited because the types, properties, additives, and contaminants of the collected plastics vary. Usually, the quality of recycled plastics is degraded. Chemical recycling into starting materials or value-added chemicals has emerged as a more desirable method.

[0009] However, a more robust process is needed to industrially and massively chemically recycle disposable plastics to reduce their environmental impact. 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 or value-added chemicals or fuels. By establishing such a circular economy and also using renewable resources such as bio-based raw materials, the environmental advantages of such recycling processes can be further enhanced. SUMMARY OF THE INVENTION

[0010] Provided is an integrated process for converting plastic waste into recycling for polyethylene polymerization. This process includes selecting waste plastics to blend with biofeedstock, and the blend of waste plastics and biofeedstock is then supplied to a conversion unit and converted. This conversion process produces clean monomers and chemical intermediates for ethylene polymerization. This blend contains about 20 wt% or less of the selected waste plastics. In one embodiment, the blend is supplied to a purification conversion unit such as an FCC unit.

[0011] The term "bio" refers to biochemical and / or natural chemical substances that exist in nature. Thus, biofeedstock or bio-oil will include such natural chemical substances. Preferred starting biofeedstocks for blend preparation include triglycerides, fatty acids, plant-derived oils (such as palm oil, canola oil, corn oil, and soybean oil), and animal-derived fats and oils (such as tallow, lard, schmalz (e.g., chicken fat), and fish oil), as well as mixtures thereof.

[0012] Integrating this process into an oil refinery is an important aspect of this process, and disposable waste plastics such as polyethylene can be used to realize a circular economy. Thus, the blend is passed through a purification FCC unit. The blend is passed at a temperature above its pour point so that it can be pumped to the purification FCC unit. The blend is heated to a temperature above the melting point of the plastic before being injected into the reactor. From the FCC unit, a liquefied petroleum gas C3 olefin / paraffin mixture is recovered. The C3 olefin / paraffin mixture is passed through a steam cracker to produce ethylene, and polyethylene and polyethylene products can be prepared from the ethylene.

[0013] In another embodiment, the C4 olefin / paraffin mixture is recovered from the FCC unit, similar to the C3 mixture. These two streams are passed together through a steam cracker to produce ethylene. This mixture can also contain naphtha (C5-C8), if desired.

[0014] A refinery generally has its own hydrocarbon feed flowing through refinery units. An important aspect of this process is that it should not have an adverse impact on the operation of the refinery. The refinery still has to produce valuable chemicals and fuels. Otherwise, incorporating this process into an oil refinery would not be a viable solution. Therefore, the flow rates need to be carefully monitored.

[0015] The volume of the flow of the waste plastic / biofeed blend to the refinery unit can be constituted by any practical or acceptable volume percentage (vol%) of the total flow to the refinery unit (total flow rate). Generally, the flow rate of the blend can be up to about 100 vol% of the total flow rate (i.e., in this maximum case, the blend flow rate is the total flow rate excluding the refinery flow rate). In one embodiment, the flow rate of the blend is an amount up to about 50 vol% of the total flow rate (i.e., the refinery flow rate plus the blend flow rate).

[0016] Among other factors, it has been found that the blend of waste plastics and bio-based materials can be adjusted, and this blend is stable enough to be stored or transported as required. Furthermore, this blend can be converted into value-added chemicals or fuels in a conversion unit. The combined use of waste plastics and bio-based materials significantly improves the environmental aspects of the conversion and recycling processes. Additionally, by incorporating the conversion unit as part of a refinery operation, waste plastics can be recycled efficiently and effectively, while also complementing the refining operations involved in the preparation of high-value products such as gasoline, jet fuel, base oils, and diesel. However, it has also been found that by adding a refining operation, it is possible to efficiently and effectively produce clean LPG (propane, propylene, butane, and butene) and naphtha from waste plastics and ultimately produce polyethylene polymers. Throughout the process from recycled plastics to polymer products with product quality equivalent to that of virgin polymers, the plus economics are realized, and by utilizing the blend of bio-based materials and waste plastics, the environmental aspects of the recycling process are also enhanced.

Brief Description of the Drawings

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Embodiments for Carrying Out the Invention

[0024] This process provides a method for recycling waste plastics such as polyethylene and / or polypropylene into valuable chemicals and fuels, and virgin polyethylene. Most of the polyethylene and polypropylene polymers are used in 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 polyethylene and polypropylene into valuable chemicals and fuel products. Currently, only a small amount of polyethylene / polypropylene is recycled through chemical recycling, and the recycled and purified polymer pellets are pyrolyzed in a pyrolysis unit to produce fuel (naphtha, diesel), steam cracker feedstock, or slack wax.

[0025] Ethylene is the most produced basic building block of petrochemistry. Ethylene is produced hundreds of millions of tons 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 carried out at very high temperatures up to 850 °C.

[0026] Polyethylene is widely used in various consumer and industrial products. Polyethylene is the most common plastic, and over 100 million tons of polyethylene resin are produced annually. Its main use is in packaging (containers such as plastic bags, plastic films, geomembranes, bottles, etc.). Polyethylene is produced in the following three main forms, which have the same chemical formula (C2H4) n but different molecular structures: high-density polyethylene (HDPE, about 0.940 - 0.965 g / m -3 ), linear low-density polyethylene (LLDPE, about 0.915 - 0.940 g / cm -3 ), low-density polyethylene (LDPE, < 0.930 g / cm -3 ). HDPE has a low degree of branching and short side chains, while LDPE has a very high degree of branching and long side chains. LLDPE is a substantially linear polymer with a significant number of short branches and is usually made by copolymerization of ethylene and short-chain alpha olefins.

[0027] Low-density polyethylene (LDPE) is produced by radical polymerization at very high pressures of 150 - 300 °C and 1,000 - 3,000 atmospheres. In this process, a small amount of oxygen and / or an organic peroxide initiator is used to produce a polymer having about 4,000 - 40,000 carbon atoms per average polymer molecule and having many branches. High-density polyethylene (HDPE) is produced in the presence of a catalyst at relatively low pressures (10 - 80 atmospheres) and temperatures of 80 - 150 °C. Ziegler-Natta organometallic catalysts (titanium(III) chloride having an alkyl aluminum) and Phillips-type catalysts (chromium(IV) oxide supported on silica) are typically used, and this 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 ethylene to control the chain length of the polymer. The production conditions for linear low-density polyethylene (LLDPE) are the same as those for HDPE, except for the copolymerization of ethylene and a short-chain alpha olefin (1-butene or 1-hexene).

[0028] Today, due to the inefficiency and ineffectiveness of the recycling efforts described above, only a small portion of used polyethylene products are collected for recycling.

[0029] Recycling processes that return plastic waste to clean monomers are currently available, in which waste plastics and bio-based raw materials are simultaneously converted in a conversion unit. The clean monomers can be used as monomers for polymerization for value-added chemicals, fuels (e.g., recycling of polyethylene). This process includes preparing a novel blend of waste plastics and bio-based raw materials. This blend is converted in a conversion unit such as a catalytic process unit. In an integrated process, raw materials for producing clean monomers for polymerization are generated. In an integrated process, clean recycled propane, propylene, butane, and naphtha streams are generated, which serve as raw materials for an ethylene steam cracker and ultimately as raw materials for polyethylene production. Recycling of plastic waste does not degrade the quality of the final polyethylene product.

[0030] In parallel, high-quality gasoline, jet, and diesel fuels can be produced at a refinery from waste plastics. The fuel components are upgraded in appropriate refining units via a chemical conversion process. The final transportation fuels produced by the integrated process are of high quality and meet the fuel quality requirements.

[0031] A simplified process diagram of the basic case of the waste plastic pyrolysis process commonly practiced in today's industry is shown in FIG. 1. Generally, waste plastics are sorted together (1). The washed waste plastics 2 are converted in the pyrolysis unit 3 into off-gas 4 and pyrolysis oil (liquid product). The off-gas 4 from the pyrolysis unit is used as fuel for operating the pyrolysis unit. The on-site distillation unit separates the pyrolysis oil to produce naphtha and diesel 5 products, which are sold in the fuel market. The heavy pyrolysis oil fraction 6 is recycled to the pyrolysis unit 3 to maximize the fuel yield. The char 7 is removed from the pyrolysis unit 3. The heavy fraction 6 is rich in long-chain straight-chain hydrocarbons and is very waxy (i.e., it produces paraffinic wax when cooled to ambient temperature). The wax can be separated from the heavy fraction 6 and sold in the wax market.

[0032] By using the blend of waste plastics / biomass feedstock of the present invention, many advantages can be obtained compared to the pyrolysis process. In this process, the waste plastics are not pyrolyzed. Instead, the blend of biomass feedstock and waste plastics is directly converted in the conversion unit.

[0033] The blend is prepared in a high-temperature blend preparation unit with an operating temperature exceeding the melting point of the plastic (about 120 - 300 °C), and a homogeneous liquid blend of plastic and bio-oil at high temperature can be produced. The homogeneous liquid blend of plastic and biomass feedstock at high temperature can be directly fed to the conversion unit.

[0034] The preferred range of plastic in the composition blend is about 1 - 20 wt%. In one embodiment, the conditions for preparing the high-temperature liquid blend include heating the blend to a temperature above the melting point of the plastic while vigorously mixing it with the bio-based raw material. The process conditions include heating to 250 - 550°F, a residence time at the final heating temperature of 5 - 240 minutes, and an atmospheric pressure of 0 - 10 psig. This can be carried out even in open air, preferably also in an oxygen-free atmosphere.

[0035] Alternatively, the blend is prepared in a stable blend preparation unit, and the high-temperature homogeneous liquid blend is cooled to ambient temperature in a controlled manner so that it can be easily stored and transported. By using this method, a stable blend can be prepared at a remote facility away from the refinery and transported to the refining unit. The stable blend is then heated to a temperature above the melting point of the plastic and fed to the purification conversion unit. The stable blend is a physical mixture of micron-sized plastic particles finely suspended in a petroleum-based oil. This mixture is stable, and the plastic particles do not precipitate or agglomerate even after long-term storage.

[0036] The stable blend of the present invention is produced by a two-step process. In the first step, a high-temperature homogeneous liquid blend of the plastic melt and the bio-based raw material is produced. The preferred range of the plastic composition in the blend is about 1 - 20 wt%. In one embodiment, the conditions for preparing the high-temperature liquid blend include heating the plastic to a temperature above the melting point of the plastic while vigorously mixing it with the bio-based raw material. The preferred process conditions include heating to 250 - 550°F, a residence time at the final heating temperature of 5 - 240 minutes, and an atmospheric pressure of 0 - 10 psig. This can be carried out even in open air, preferably also in an oxygen-free inert atmosphere.

[0037] In the second step, the hot blend is cooled to a temperature below the melting point of the plastic while continuously and vigorously mixing it with the bio-based raw material, and further cooled to a low temperature, preferably ambient temperature, to produce a stable blend.

[0038] The resulting composition contains a stable blend of waste plastic and bio-based raw material and is for directly converting waste plastic in a conversion unit such as a purification process unit. The resulting composition is novel and brings many advantages.

[0039] The stable blend is made from a bio-based raw material and 1 - 20 wt% plastic waste, and the plastic is mainly polyethylene, polypropylene and / or polystyrene, and the plastic is in the form of finely dispersed micron-sized particles.

[0040] The significance of heating the blend to a temperature above the melting point of the plastic becomes clear when using a single plastic. However, when the waste plastic is composed of multiple waste plastics, it will exceed the melting point of the plastic with the highest melting point. Therefore, it must exceed the melting point of all plastics. Similarly, when cooling the blend to a temperature below the melting point of the plastic, the temperature must be cooled to a temperature below the melting point of all plastics constituting the blend.

[0041] By implementing these concepts, several advantages are realized compared to pyrolysis.

[0042] The stable blend of plastic and bio-based raw material can be stored for a long time at ambient temperature and atmospheric pressure. During storage, no polymer aggregation or chemical / physical degradation of the blend is observed. This facilitates the handling of waste plastic materials during storage or transportation.

[0043] A stable blend can be easily handled by using standard pumps typically used in refineries or warehouses, or pumps equipped with transport tanks. Depending on the blend, it may be necessary to heat the blend to a temperature above its pour point in order to transfer the blend using a pump or supply it to a conversion unit within the refinery. During heating, no polymer aggregation is observed.

[0044] To supply the conversion unit, the stable blend is further heated to a temperature exceeding the melting point of the plastic, producing a homogeneous liquid blend of the biofeedstock and the plastic. This homogeneous liquid blend at this high temperature is directly supplied to a petroleum refining process unit in order to convert waste plastic and biofeedstock into high-value and sustainable products with high yields.

[0045] Also, compared to pyrolysis units, these blend preparation units operate at much lower temperatures (about 500°C - 600°C vs. 120°C - 300°C). Therefore, this process is much more energy-efficient in preparing refined raw materials from waste plastics than pyrolysis processes such as pyrolysis.

[0046] The use of the waste plastic / biofeedstock blend of the present invention further increases the overall yield of hydrocarbons obtained from waste plastics. This increase in yield is significant. The hydrocarbon yield using this blend can reach up to 98%. In contrast, pyrolysis produces a significant amount of light products of about 10 - 30 wt% and about 5 - 10 wt% char from plastic waste. These light hydrocarbons are used as fuel to operate the pyrolysis plant as described above. Therefore, the liquid hydrocarbon yield from the pyrolysis plant is at most 70 - 80%.

[0047] Also, when this blend is passed through a purification unit such as an FCC unit, only a small amount of off-gas is generated. In the purification unit, a (catalytic) catalytic cracking process different from the pyrolysis process used in pyrolysis is used. When using the catalytic process, the generation of undesirable light by-products such as methane and ethane can be minimized. In the purification unit, efficient product fractionation is performed, and all hydrocarbon product streams can be efficiently utilized to produce high-value materials. In the co-feed of the refinery, only about 2% of off-gas (H2, methane, ethane, ethylene) is generated. The C3 stream and the C4 stream are captured to produce useful products such as cyclic polymers and / or high-quality fuel products. Therefore, the use of the oil / plastic blend of the present invention not only leads to an increase in hydrocarbons from waste plastics, but also realizes a more energy-efficient recycling process compared to heat treatment processes such as pyrolysis.

[0048] This process converts large amounts of disposable waste plastics by blending waste plastics with a biofeedstock stream and integrating it into an oil refinery operation. The resulting process produces polymer feedstocks (naphtha or C3 and C4 for ethylene crackers), as well as high-quality gasoline, jet fuel, and diesel, and / or high-quality base oils.

[0049] Generally, this process provides a circular economy for a polyethylene plant. Polyethylene is produced through the polymerization of pure ethylene. Clean ethylene can be produced using a steam cracker. Any stream of naphtha or C3 or C4 can be fed to the steam cracker. Then, ethylene is polymerized to produce polyethylene.

[0050] By adding purification operations to upgrade waste plastics into high-value products (gasoline, jet fuel, diesel, base oil) and to produce clean ethylene for the production of the ultimate polyethylene polymer, the plus economics is realized throughout the process from recycled plastics to polyethylene products with quality equivalent to that of virgin polymers. Also, by integrating this recycling process with petroleum refining operations, a more energy-efficient and effective process is achieved while avoiding the problems of purification operations.

[0051] The integration of purification operations is also very important in another aspect. Waste plastics contain contaminants such as calcium, magnesium, chlorides, nitrogen, sulfur, dienes, and heavy components, and these products cannot be used in large quantities for blending transportation fuels. It has been found that by passing these products through a purification unit, the contaminants can be captured in a pretreatment unit and their adverse effects can be reduced. The fuel components can be further upgraded in a suitable purification unit using 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. The integrated process produces a much cleaner and purer ethylene stream for polyethylene production. By mass-producing according to these specifications, the "circular economy" of recycled plastics becomes achievable.

[0052] The carbon flowing in and out in the purification operation is "transparent", which means that not all molecules from waste plastics circulate back to the polyolefin plant and become the exact olefin products. Nevertheless, since the net "green" carbon flowing in and out of the refinery is positive, it is regarded as "credit". These integrated processes will significantly reduce the amount of virgin feedstock required for the polyethylene plant.

[0053] Figure 2 shows a method for preparing a high-temperature homogeneous blend of plastic and bio-based raw materials according to this process. This high-temperature liquid blend can be used for direct injection into a conversion unit. The preferred range of the plastic composition in the blend is about 1 - 20 wt%. When waste plastics of high molecular weight polypropylene (average molecular weight of 250,000 or more) or high-density polyethylene (density exceeding 0.93 g / cc) are mainly used as, for example, at least 50 wt% of the waste plastics, the amount of waste plastics used in the blend is more preferably about 10 wt%. The reason is that the pour point and viscosity of the blend increase.

[0054] Preferred conditions for the preparation of the blend include heating the plastic to a temperature above its melting point while vigorously mixing it with the bio-based raw material. Preferred process conditions include heating to a temperature of 250 - 550°F, a residence time at the final heating temperature of 5 - 240 minutes, and an atmospheric pressure of 0 - 10 psig. This can be carried out even in an open atmosphere and preferably also in an oxygen-free inert atmosphere.

[0055] Referring to Figure 2 of the drawings, a step-by-step preparation process for preparing a blend of plastic and bio-based raw materials is shown. The mixed waste plastics are sorted to produce consumer post-use waste plastics 21 containing polyethylene and / or polypropylene. The waste plastics are cleaned (22) and then mixed with bio-based raw material oil 24 in a high-temperature blend preparation unit 23. After mixing at 23, a high-temperature homogeneous blend of plastic and bio-oil is recovered (25). Optionally, a filtration device can be added (not shown) to remove undissolved plastic particles or solid impurities present in the liquid blend. The blend of plastic and bio-oil can then be passed through a catalytic conversion unit 27. In this process, in one embodiment, the conversion unit is a purification unit such as an FCC unit. Optionally, the conversion unit can co-process vacuum gas oil 20 or other conventional raw materials from a refinery.

[0056] Figure 3 shows a method for preparing a stable blend of plastic and oil for use in this process. The stable blend is produced by a two-step process in a stable blend preparation unit. In the first step, a homogeneous liquid blend of plastic melt and biofeedstock is produced at a high temperature. This step is the same as the high-temperature blend preparation described in Figure 2. The preferred range of the plastic composition in the blend is about 1-20 wt%. When waste plastic of high molecular weight polypropylene (average molecular weight of 250,000 or more) or high-density polyethylene (density exceeding 0.93 g / cc) is mainly used, for example, as at least 50 wt% of the waste plastic, the amount of waste plastic used in the blend is more preferably about 10 wt%. The reason is that the pour point and viscosity of the blend increase.

[0057] Preferred conditions for the preparation of the high-temperature homogeneous liquid blend include heating the plastic to a temperature above the melting point of the plastic while vigorously mixing with the biofeedstock. Preferred process conditions include heating to a temperature of 250-550°F, a residence time at the final heating temperature of 5-240 minutes, and an atmospheric pressure of 0-10 psig. This can be carried out in open air and preferably also under an inert atmosphere without oxygen.

[0058] In the second step, the high-temperature blend is cooled to a temperature below the melting point of the plastic while continuously and vigorously mixing. Any diluent can be added during mixing. Further cooling to a low temperature, preferably ambient temperature, produces a stable blend of plastic and oil.

[0059] A stable blend has been found to be a close physical mixture of plastic and bio-based raw materials. The plastic is in a "de-aggregated" state. The plastic maintains a finely dispersed state of the solid particles in the bio-based raw materials at a temperature lower than the melting point of the plastic, particularly at ambient temperature. The blend is stable and easy to store and transport. At the refinery, the stable blend can be heated in a pre-heater to a temperature higher than the melting point of the plastic to produce a homogeneous liquid blend of plastic and bio-based raw materials at high temperature. This high-temperature liquid blend can then be fed to a refining unit either alone or as a co-feed together with conventional refining raw materials.

[0060] Figure 3 shows further details of the preparation of the stable blend. The stable blend is made in a two-step process in a stable blend preparation unit 100. As shown, clean waste 22 is passed through a high-temperature blend preparation unit 23. The selected plastic waste 22 is mixed with bio-based raw material oil 24 and heated in unit 23 to a temperature above the melting point of the plastic. The mixing is often carried out very vigorously. The mixing and heating conditions can generally be heating at a temperature in the range of about 250 - 550°F and heating with a residence time of 5 - 240 minutes at the final heating temperature. The heating and mixing can be carried out in open air or under an oxygen-free inert atmosphere. As a result, a homogeneous liquid blend 101 of plastic and oil at high temperature is obtained. Optionally, a filtration device (not shown) can be added to remove undissolved plastic particles or solid impurities present in the high-temperature homogeneous blend.

[0061] Next, the hot blend 101 is cooled in unit 102 to a temperature below the melting point of the plastic while continuing to mix the blend of plastic and bio-based raw material. During mixing and cooling, any diluent 103 can be added. Cooling is typically continued to ambient temperature, producing a stable blend of plastic and oil 29. At the refinery, the stable blend can be fed to a preheater 130, which heats the blend to a temperature above the melting point of the plastic to produce a homogeneous mixture at an elevated temperature of the plastic / oil blend 105, which is then fed to a refining conversion unit 27. Optionally, the conversion unit can co-process vacuum gas oil or other conventional refining feedstocks.

[0062] Preferred plastic starting materials for this process are sorted waste plastics mainly comprising 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 blend preparation unit. Figure 4 shows the plastic type classification for the recycling of waste plastics. 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 plastics of polyethylene. Polystyrene (classification 6) can also be present in limited amounts.

[0063] To minimize contaminants such as N, Cl, S, etc., it is very important to appropriately sort waste plastics. Plastic wastes 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 20%, preferably less than 10%, and most preferably less than 5%.

[0064] By washing waste plastics, metal contaminants such as sodium, calcium, magnesium, aluminum, etc., and non-metal contaminants from other waste sources can be removed. Non-metal contaminants include contaminants from Group IV of the periodic table such as silica, contaminants from Group V such as phosphorus compounds and nitrogen compounds, contaminants from Group VI such as sulfur compounds and oxygen compounds, and halide contaminants from Group VII such as fluorides, chlorides, iodides, etc. 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.

[0065] The term "bio" refers to biochemical and / or natural chemicals existing in nature. Thus, bio feedstock or bio-oil will contain such natural chemicals. Preferred starting bio feedstocks for blend preparation include triglycerides, fatty acids, plant-derived oils (such as palm oil, canola oil, corn oil, and soybean oil), and animal-derived fats and oils (such as tallow, lard, schmalz (e.g., chicken fat), and fish oil), as well as mixtures thereof. In one embodiment, the bio feedstock can include biomass pyrolysis oil prepared by pyrolyzing bio feedstock materials.

[0066] The most preferred bio-based materials are palm oil and tallow, which have a high degree of saturation and an iodine number of 91 or less (i.e., a low degree of unsaturation). The iodine number (iodine number or iodine value) is a measure of the unsaturation of fats, oils, and waxes. It is determined by measuring the mass (in grams) of iodine consumed by 100 g of the substance. The higher the value, the higher the degree of unsaturation of the substance. This is similar to using the bromine number to measure the unsaturation of petroleum samples.

[0067] Bio-based materials containing polyunsaturated fatty acids with a high iodine number, such as soybean oil (iodine number 130), have been found not to form a stable blend with plastics. However, a bio-based material mixture consisting of a bio-based material with a low iodine number (≤70) and a bio-based material with a high degree of iodination (>70) can form a stable blend with plastics. It has been found that bio-based material mixtures with an iodine number of about 95 or less can form a stable blend with plastics. In one embodiment, the mixture of bio-based materials has an iodine number of 91 or less.

[0068] Furthermore, the blend of plastic and bio-based material can be blended with other diluent hydrocarbons, such as heptane, as needed to change the properties of the blend, such as viscosity or pour point, and to facilitate handling and processing. Preferred blend hydrocarbon raw materials include standard petroleum-based raw materials such as vacuum gas oil (VGO), aromatic solvents, or light cycle oil (LCO). In one embodiment, the blend hydrocarbon raw material includes straight-run gas oil, VGO, or heavy fractions recovered from other refining operations. In another embodiment, the blend hydrocarbon raw material includes LCO, heavy cycle oil (HCO), FCC naphtha, gasoline, diesel, toluene, or aromatic solvents derived from petroleum. To lower the viscosity, a portion of the liquid FCC product (e.g., naphtha and LCO) can also be recycled to the blend. In one embodiment, no petroleum raw material is used, and only bio-based materials are used for making the blend and mixing with the blend.

[0069] While not wishing to be bound by theory, the prepared stable blend is a close physical mixture of plastic and biofeedstock for the catalytic conversion unit. This process produces a stable blend of biofeedstock and plastic, with the plastic in a “de-aggregated” state. This blend is stable and easy to store and transport. At the refinery, the stable blend is preheated to a temperature above the melting point of the plastic to produce a homogeneous liquid blend of plastic and biofeedstock at high temperature, which is then fed to the conversion unit. Thereafter, both the biofeedstock and the plastic are simultaneously converted in the conversion unit using a typical refining catalyst containing zeolite and other active components such as silica alumina, alumina, and clay.

[0070] Catalytic conversion units such as fluid catalytic cracking (FCC) units, hydrocracking units, and hydrotreating units convert a homogeneous liquid blend of plastic and biofeedstock at high temperature using the simultaneous conversion of plastic and biofeedstock in the presence of a catalyst. The presence of a catalyst in the conversion unit enables the conversion of waste plastics into high-value products at an operating temperature lower than typical pyrolysis temperatures. In hydrogenation processing units (hydrocracking units and hydrotreating units), hydrogen is added to the unit to improve the conversion of the plastic.

[0071] The fluid catalytic cracking process is a preferred mode of catalytic conversion of the stable blend. The catalyst selection is optimized to maximize monomer production for the manufacture of virgin plastics.

[0072] The yield of unwanted by-products (off-gas, tar, coke) is lower than that of typical pyrolysis processes. This blend may produce additional synergistic effects resulting from the interaction of plastic and biofeedstock during the conversion process.

[0073] The blending of plastic and bio-based raw materials enables more efficient recycling of waste plastics and enables the production of truly circular and sustainable plastics and chemicals. This is far more energy-efficient than current pyrolysis processes and enables recycling with a lower carbon footprint. The improved process allows for the establishment of a much larger circular economy by efficiently converting waste plastics into virgin-quality ethylene polymers or valuable chemicals and fuels.

[0074] Alternatively, the blend of plastic and bio-based raw materials can be supplied to a petroleum refining conversion unit and co-processed with petroleum-based oil. Refining conversion units such as fluid catalytic cracking (FCC) units, hydrocracking units, and hydrotreating units are preferred for simultaneously converting plastic, bio-based raw materials, and petroleum-based oil.

[0075] In such cases, the refinery generally has its own hydrocarbon feed flowing through the refining unit. For example, the hydrocarbon feedstock can be VGO. The volume of the blend stream flowing into a refining unit such as an FCC unit can constitute any practical or manageable volume percentage (vol%) of the total stream flowing into the refining unit (total flow rate). Generally, for practical reasons, the blend flow rate can be up to about 50 vol% of the total flow rate (i.e., the refining flow rate and the blend flow rate). In one embodiment, the blend flow rate is an amount up to about 100 vol% of the total flow rate. The volume percentage (vol%) of the blend also varies depending on the final desired product. In the case of chemicals centered around aromatic compounds and xylene, the blend flow percentage (flow%) can be much higher, if not 100%. In another embodiment, the volumetric flow rate of the blend is an amount up to about 25 vol% of the total flow rate. About 50 vol% has been found to be a very practical amount in terms of the impact on the refinery, while providing good results and being a manageable amount. It is important to avoid adverse effects on the refinery and its products. If the amount of plastic in the final blend (including the plastic / oil blend and co-feed petroleum) exceeds 20 wt% of the final blend, problems may occur in the operation of the FCC unit. The final blend means the plastic / oil blend and any co-feed petroleum. The plastic / oil blend can account for up to 100 volume % of the feed amount to the refining unit.

[0076] In Figure 5, the decomposition of the plastic / bio-oil high-temperature blend 25 can be passed through the conversion FCC unit 27 via 26, either alone or in combination with a co-fed petroleum feedstock (co-fed petroleum feed). The numbers in Figure 5 are the same as in Figures 2 and 3 and refer to the same stream or unit. The FCC unit 27 produces liquefied petroleum gas (LPG) of C3 and C4 olefin / paraffin streams 31 and 32, as well as naphtha 33 and heavy fraction 30. The C3 olefin / paraffin mixed stream 31, which is a mixture of propane and propylene, can be sent to the steam cracker 36 via 38 to produce ethylene 37. The ethylene 37 is supplied to the ethylene polymerization unit 40 to produce polyethylene and finally the polyethylene product 41.

[0077] The C4 stream 32 and at least a portion of the naphtha 33 can also be sent to the steam cracker 36 via 39 to produce ethylene 37. The ethylene is supplied to the ethylene polymerization unit 40 to produce polyethylene and finally the polyethylene product 41. Other hydrocarbon product streams (such as the heavy fraction 30) from the FCC unit 27 are sent to an appropriate purification unit 34 and upgraded to clean gasoline, diesel, or jet fuel. The naphtha / gasoline 33 from the FCC unit may be passed directly to the gasoline pool 35 or further upgraded (not shown) before being sent to the gasoline pool.

[0078] Figure 6 shows the integrated process of the present invention as shown in Figure 5, and the blend and the co-feed of the hydrocarbon purification flow 26 are first sent to the fluid catalytic cracking (FCC) feed pretreatment unit 77. The numbers in Figure 6 that are the same as in Figure 5 refer to the same stream or purification unit.

[0079] The FCC feed pretreatment unit typically uses a bimetallic (NiMo or CoMo) alumina catalyst in a fixed-bed reactor to hydrogenate the feed using a H2 gas flow at a reactor temperature of 660 - 780°F and a pressure of 1,000 - 2,000 psi. The purified FCC feed pretreatment unit is effective in removing sulfur, nitrogen, phosphorus, silica, dienes, and metals that would otherwise impair the catalyst performance of the FCC unit. Additionally, this unit hydrogenates aromatics and improves the liquid yield of the FCC unit.

[0080] The pretreated hydrocarbons from the feed pretreatment unit 77 can be distilled to produce LPG, naphtha, and a heavy fraction. The heavy fraction is sent to the FCC unit 27, where C3, C4, FCC gasoline, and a heavy fraction (each reference numeral is 31, 32, 33, and 30 in order) are further produced. The C4 stream and naphtha from the feed pretreatment unit can be passed through other upgrading processes within the refinery. The C3 stream 31 can be passed through a steam cracker 36 to produce ethylene 37.

[0081] The steam cracker and ethylene polymerization unit are preferably located near the refinery so that the raw materials (propane, butane, naphtha, or propane / propylene mixture) can be transferred via pipeline. In the case of a petrochemical plant located far from the refinery, the raw materials can be delivered via truck, barge, railroad car, or pipeline.

[0082] The merits of circular economy and an effective and efficient recycling campaign are realized by this integrated process.

[0083] The following examples are provided as illustrations of the blends and processes of the present invention and are not intended to be limiting.

Example

[0084] [Example 1] Characteristics of Plastic Samples and Biofeedstocks Used for Blend Preparation Five plastic samples (low-density polyethylene (LDPE, Plastic A), high-density polyethylene (HDPE, Plastic B), two polypropylene samples with an average molecular weight of about 12,000 (PP, Plastic C) and about 250,000 (PP, Plastic D), and polystyrene (PS, Plastic E)) were purchased and their properties are summarized in Table 1. [Table 1]

[0085] The bio-based raw materials used to prepare blends with the plastic melt included palm oil, tallow, and soybean oil, and their properties are shown in Table 2. [Table 2]

[0086] Thermogravimetric analysis (TGA) was performed on Plastic A (LDPE) and Plastic C (polypropylene) to confirm that the plastic materials were thermally stable at temperatures well above the melt preparation temperature. The TGA results shown in Figure 7 indicate that the LDPE sample was stable up to 800°F and the polypropylene sample was stable up to 700°F.

[0087] [Example 2] Preparation of a Stable Blend of Palm Oil and Plastic Several blends of palm oil and plastic were prepared by adding plastic pellets (Plastics A - D) to palm oil (bio-based raw material #1).

[0088] Use the following procedure. At ambient temperature, palm oil (waxy solid) was placed in a beaker. The palm oil was heated with a heating mantle while stirring with a magnetic stirrer. The temperature of the palm oil was gradually increased to 270°F - 400°F, and then the pre-weighed plastic pellets (solids) were slowly added to the hot palm oil while stirring and heating. After the plastic pellets were dissolved, the stirred solution was held at the final temperature for an additional 30 minutes in the case of blends using LDPE and plastic C polypropylene, and 60 minutes in the case of blends using HDPE and plastic D polypropylene. Thereafter, the blend was cooled to ambient temperature while stirring. Visual observation showed that the mixture was completely homogeneous. When cooled to ambient temperature, the blend of plastic and palm oil exhibited the appearance of the waxy solid of palm oil, but the hardening temperature (or solidification temperature) was different from that of the palm oil at the start of the procedure.

[0089] To evaluate the handling requirements of the materials, the pour point (by ASTM D5950-14) and viscosity (by ASTM D445) of the blends were measured. Additionally, the high-temperature heptane-insoluble content was measured according to the procedure of ASTM D3279. In the high-temperature heptane-insoluble method, the weight percentage of substances in the oil that are insoluble in high-temperature heptane at 80°C is measured. In this method, a 0.8-micron membrane filter is used to separate the insoluble substances. The heptane-insoluble content provides information regarding the undissolved plastic in the blend.

[0090] The stability of the materials was observed by visual inspection. The blend of plastic and palm oil was stable, and no changes were observed during the 3-month observation period.

[0091] Table 3 below summarizes the list of prepared samples and their properties.

Table 3

[0092] The values of the pour point and viscosity are used as guidelines for equipment selection and operating procedures. Blends prepared by adding plastic show a moderate increase in pour point and viscosity compared to the pure bio-based case. These changes can be accommodated with minor or no modifications in typical refining operation equipment. The blend tank is heated to a temperature above the pour point to transform the physical state of the blend into a liquid that can be easily transferred. Subsequently, the liquid blend can be transferred to a transport container or a refining unit via pump transportation by a pump, discharge by gravity, or transfer by a pressure difference.

[0093] The stable blend remains a physical mixture at temperatures up to 80 °C. The plastic was separated from the blend using a hot heptane insolubility test. At 80 °C, all the waxes in the palm oil were dissolved in the heptane solvent (Example 2-1), and the heptane-insoluble solids were only 0.02 wt%. The weight percentage of the heptane-insoluble substances is derived from the undissolved plastic filtered through a 0.8-micron membrane filter. The amounts recovered as solid substances in Examples 2-2 and 2-4 indicate that the heptane-insoluble solids are 7.6 wt% and 7.8 wt%, which is approximately the same as the amount of plastic added for blend preparation. Since the recovered amounts are 2.2 wt% - 2.4 wt% less, it is suggested that the blend may contain very fine particles of submicron size. The heptane-insoluble results in Table 3 clearly show that the plastic is a physical mixture of solid particles dispersed in the palm oil in the 80 °C blend, and most of the plastic particles can be separated by a 0.8-micron filter.

[0094] [Example 3] Preparation of a Stable Blend of Tallow and Plastic Several blends of tallow and plastic samples were prepared by adding plastic pellets to tallow raw material (Bio-based raw material #2).

[0095] The procedures described in Example 2 were used for these blend preparations.

Table 4

[0096] The blend prepared by adding plastic to tallow had a moderately increased pour point and viscosity compared to the pure bio-based case, similar to the results of palm oil shown in Example 2.

[0097] The weight percentage of the heptane-insoluble substances recovered as solids is in good agreement with the amount of plastic added to the blend preparation. The tallow in the basic case (Example 3-1) contains only 0.04 wt% of heptane-insoluble matter, while the stable blends (Examples 3-2 and 3-4) contain 7.7 wt% and 8.6 wt% of heptane-insoluble solids, which is almost the same as the amount of plastic added for blend preparation. Since the recovered amount is 1.4 wt% to 2.3 wt% less, it is suggested that the blend may contain very fine particles of submicron size. The heptane-insoluble results in Table 4 clearly show that the plastic is a physical mixture of solid particles dispersed in palm oil in the 80 °C blend, and that most of the plastic particles can be separated by a 0.8 micron filter.

[0098] [Example 4] Preparation of a blend of soybean oil and plastic (comparative example) A blend of soybean oil (bio - raw material #3) and plastic was attempted to be prepared using plastic pellets (Plastics A - D) with the procedure described in Example 2. Surprisingly, even when soybean oil and plastic were heated together in the same way as in the case of palm oil or animal fat, they did not form a homogeneous liquid melt at high temperature. When the mixture was heated above the melting point of the plastic, the pellets became soft and lost their shape. However, instead of forming a homogeneous liquid as in other cases, the plastic melt formed a separate liquid phase from soybean oil (SBO). Upon cooling, the plastic phase aggregated and formed large plastic solid pieces. The reason considered for this is that the unsaturation of SBO is much higher. This is also evident from the fact that the H / C ratio is lower than that of animal fat or palm oil, and is also evident from the measured iodine value. Also, the reason why most petroleum raw materials and highly saturated oils and fats determined by the iodine value can easily dissolve plastic can be explained by this. [Table 5]

[0099] [Example 5] Preparation of a Blend of Soybean Oil, Palm Oil, and Plastic A mixture of soybean oil and palm oil in a weight ratio of 1:1 (mixed bio - raw material) was prepared. Using the mixed bio - raw material, a blend of palm oil, soybean oil, and plastic was successfully prepared by adding plastic pellets (Plastics A and C) to a 1:1 mixture of palm oil and soybean oil (bio - raw material #1 and bio - raw material #3). Therefore, soybean oil can be used as a component of the mixed bio - raw material. The stable blend showed a good shelf life and showed no change for several months. These results indicate that by using soybean oil together with another bio - raw material to reduce the unsaturation, soybean oil can also be used as a bio - raw material for preparing a stable blend with plastic.

[0100] This test also shows the iodine value that can be tolerated to successfully produce a stable blend of plastic and bio-based raw materials. The iodine value of a 1:1 mixture of soybean oil and palm oil is estimated to be 91. These results indicate that soybean oil or other highly unsaturated oils can also be used as bio-based raw materials for preparing a stable blend with plastic as long as the overall unsaturation of the blended bio-based raw materials is 95 or less, preferably 91 or less in iodine value. [Table 6]

[0101] [Example 6] Preparation of a Blend of Soybean Oil, Tallow, and Plastic A 1:1 mixture of soybean oil and tallow was prepared. Using the blended bio-based raw materials, a blend of tallow, soybean oil, and plastic was successfully prepared by adding plastic pellets (Plastic A and C) to the 1:1 mixture of tallow and soybean oil (Bio-based raw material #2 and Bio-based raw material #3). The stable blend showed a good shelf life and no changes were observed for several months. These results again indicate that soybean oil can also be used as a bio-based raw material for preparing a stable blend with plastic by reducing the unsaturation using soybean oil together with another bio-based raw material.

[0102] This test also shows the iodine value that can be tolerated to successfully produce a stable blend of plastic and bio-based raw materials. The iodine value of a 1:1 mixture of soybean oil and tallow is estimated to be 88. [Table 7]

[0103] To investigate the impact of treating waste plastics and bio-based raw materials in an FCC unit, laboratory tests were conducted using a fluid catalytic cracking (FCC) process with a stable blend of plastic and bio-based raw materials. In this test, two FCC catalysts were used. One was a ZSM-5-containing FCC catalyst made of ZSM-5 zeolite (a 10-membered ring medium-pore zeolite), and the other was a USY-containing FCC catalyst made of USY (a 12-membered ring medium-pore zeolite). Three bio-based raw materials, palm oil, soybean oil, and tallow, were used.

[0104] (Catalyst) The catalytic cracking experiment was carried out in an ACE (Advanced Cracking Evaluation) Model C unit manufactured by Kayser Technology Inc. (Texas, USA). The reactor used in the ACE unit was a fixed fluidized bed reactor with an inner diameter of 1.6 cm. Nitrogen was used as the fluidizing gas and introduced from both the bottom and the top. The upper fluidizing gas was used to carry the feed injected from a calibrated syringe pump through a three-way valve. The experiment was carried out at atmospheric pressure and a temperature of 975°F. In each experiment, a fixed amount of 1.5 grams of feed was injected at a rate of 1.2 grams / minute for 75 seconds. The catalyst / oil ratio was maintained at 6. After 75 seconds of feed injection, the catalyst was stripped with nitrogen for 525 seconds. During the catalytic cracking and stripping processes, the liquid products were collected in sample vials attached to a glass receiver at the end of the reactor outlet and maintained at -15°C. The gaseous products were collected in a sealed stainless steel container (12.6 L) pre-filled with N2 at 1 atm. The gaseous products were mixed by an electric stirrer rotating at 60 rpm immediately after the feed injection was completed. After stripping, the gas products were mixed for an additional 10 minutes to ensure homogeneity. The final gas products were analyzed using a refined gas analyzer (RGA). After the completion of the stripping process, in-situ catalyst regeneration was carried out in the presence of air at 1300°F. The regeneration exhaust gas passed through a catalytic converter filled with CuO pellets (LECO Inc.) to oxidize CO to CO2. Then, the exhaust gas was analyzed with an on-line IR analyzer installed downstream of the catalytic converter. The coke deposited during the cracking process was calculated from the CO2 concentration measured by the IR analyzer.

[0105] The gaseous products, mainly C1 to C7 hydrocarbons, were cracked with an RGA. The RGA is a customized Agilent 7890B GC equipped with three detectors, namely a flame ionization detector (FID) for hydrocarbons and two thermal conductivity detectors for nitrogen and hydrogen. A methanizer was also installed in the RGA to quantify trace amounts of CO and CO2 contained in the gas products when bio-based raw materials such as soybean oil, palm oil or tallow were cracked. The gas products were classified into dry gas (C2-hydrocarbons and hydrogen) and LPG (C3 and C4 hydrocarbons). CO and CO2 were excluded from the dry gas. Their yields were reported separately. The liquid products were weighed and analyzed with a simulated distillation GC (Agilent 6890) using the ASTM D2887 method. The liquid products were split into gasoline (C5~430°F), LCO (430F°~650°F), and HCO (650°F+). The gasoline (C5+ hydrocarbons) in the gaseous products was combined with the gasoline in the liquid products to give total gasoline. The light fraction (C 5- ) in the liquid products was also subtracted from the liquid products and added back to the C3 and C4 species using an empirical distribution. The material balance was between 98% and 101% in most of the experiments.

[0106] For the gasoline portion of the liquid products, detailed hydrocarbon analysis (DHA) was also carried out using an Agilent 6890A and Hydrocarbon Expert software from Separation Systems Inc. (Florida) to analyze PONA and octane (RON and MON). DHA analysis was not carried out for the gasoline portion in the gaseous products. However, the DHA results still provided valuable information in evaluating the characteristics of the (catalytic) cracking products.

[0107] [Example 7] Direct conversion of plastics and palm oil via FCC (using a ZSM-5 catalyst) Laboratory tests of the fluid catalytic cracking (FCC) process were carried out using a stable blend of plastics and bio-based raw materials (Examples 2-2 and 5-1) and an FCC catalyst made of ZSM-5 zeolite, and the results are summarized in Table 8.

Table 8

[0108] The results in Table 8 show that the blend of waste plastic and bio-based raw materials (palm oil and soybean oil) is well converted by the ZSM-5-containing FCC catalyst. Surprisingly, the medium-pore 10-ring ZSM-5 catalyst can convert more than 95 wt% of the plastic / bio-based raw material blend under typical FCC process conditions (Examples 7-1 to 7-3). Due to the high conversion rate, the yields of LCO and HCO are very low. In all these cases, very high LPG and aromatic yields are obtained, indicating that this process can be used to produce raw materials for polymer and chemical manufacturing without using petroleum resources.

[0109] Even when 10 wt% of plastic was added to palm oil, only slight changes occurred in the performance of the FCC unit in terms of the conversion rate and the yields of dry gas and coke. This suggests that the co-processing of waste plastic and bio-based raw materials is easily feasible (Examples 7-1 and 7-2). When 10 wt% of low-density polyethylene (Plastic A) was blended with palm oil, the yields of coke and dry gas increased only slightly, but significant increases in the LPG yield (35 wt% vs. 37 wt%) and the total aromatic yield (76 wt% vs. 81 wt% in the gasoline fraction) were observed. The significant increase in the LPG yield and the aromatic yield from the plastic-containing blend was completely unexpected. This clearly shows that the synergistic effect of the bio-based raw material and the plastic blend increases the yields of LPG and aromatics.

[0110] When 10 wt% of plastic was blended with palm oil and soybean oil (Example 7-3), consistent results of high LPG and aromatic compound production were also shown.

[0111] These results indicate that the ZSM-5 catalyst made of medium-pore zeolite is a favorable catalyst for the production of LPG olefins and aromatic compounds when converting bio-based raw material / plastic blends.

[0112] The high yield of LPG by this process is important. LPG and LPG olefins are preferred raw materials for the production of polyethylene and polypropylene.

[0113] The high yield of aromatics by this process is also very important because these aromatics can be used in the production of polystyrene or polyethylene terephthalate. Another surprising discovery was the selectivity of paraxylene to total xylene. When using a ZSM-5 catalyst, the xylene produced in this process is substantially paraxylene, and the paraxylene selectivity is about 61 - 70% (ratio to the total xylene production). Paraxylene is the most desirable xylene isomer for the production of polyethylene terephthalate polymers.

[0114] This process is more suitable for the production of chemical substances, but a part of the product can be used in the production of premium gasoline fuel. The gasoline produced by this process has an excellent octane number exceeding 100 because of the high aromatic content in the gasoline fraction. Due to the high conversion rate, the yields of LCO and HCO are low.

[0115] [Example 8] Direct conversion of plastics and palm oil via FCC (using USY catalyst) Laboratory tests of the fluid catalytic cracking (FCC) process were carried out using a stable blend of plastics and palm oil (Examples 2-2 and 5-1) and an FCC catalyst made of USY zeolite, and the results are summarized in Table 9.

Table 9

[0116] The results in Table 9 show that the blend of waste plastics and bio-based raw materials (palm oil and soybean oil) is well-converted over the USY-containing FCC catalyst. The overall conversion rate of the blend is 86 - 87% under typical FCC process conditions (Examples 8-1 to 8-3). In all these cases, a low dry gas yield (undesired product) and high yields of LPG, gasoline, and LCO (desired products) are obtained, indicating that this process can be used for the co-production of raw materials for chemical manufacturing and premium renewable fuels without using petroleum resources.

[0117] Even when 10 wt% of plastics was added to palm oil, only slight changes occurred in terms of the conversion rate and the yields of dry gas and coke in the performance of the FCC unit. This indicates that the co-processing of waste plastics and bio-based raw materials is easily feasible (Examples 8-1 and 8-2). Even when low-density polyethylene (Plastic A) was blended with palm oil at 10 wt%, there was only a slight effect on the product yields: LPG yield (19.5 wt% vs. 21.3 wt%), gasoline yield (45.4 wt% vs. 44.9 wt%), LCO (10.9 wt% vs. 10.0 wt%), and HCO yield (3.2 wt% vs. 3.3 wt%). However, due to the paraffinic nature of the plastic, a 3-point decrease in the gasoline octane number was observed (from 91 to 88).

[0118] When 10 wt% of plastics was blended with palm oil and soybean oil (Example 8-3), it also showed consistent results of high LPG and gasoline production.

[0119] When using the USY catalyst, the synergistic effect between the biofeedstock and plastic was not observed, nor was the para-xylene selectivity observed with the ZSM-5 catalyst shown in Example 7-2. Compared with the ZSM-5 catalyst (Example 8-2 vs. Example 7-2), the USY catalyst had a much higher yield of LCO (10.0 wt% vs. 1.4 wt%) and also a much higher yield of HCO (3.3 wt% vs. 0.7 wt%). Furthermore, USY showed a much higher coke selectivity (6.7 wt% vs. 1.7 wt%) and a lower off-gas yield (2.2 wt% vs. 6.5 wt%). These results indicate that the USY catalyst made of large-pore zeolite is a preferred FCC catalyst for simultaneously producing chemical feedstocks and premium fuels.

[0120] Part of the product can be used in the production of premium fuels. The gasoline produced in this process has an octane number of 91 - 88. Due to the paraffinicity of the plastic, adding polyethylene plastic slightly reduces the octane number. Due to the flexibility of the refinery blend, this reduction in octane number can be compensated for by fine-tuning the blend.

[0121] The high yield of LPG by this process is important. LPG and LPG olefins are preferred feedstocks for the production of polyethylene and polypropylene.

[0122] The high yield of aromatics by this process is also important because these aromatics can be used in the production of polystyrene or polyethylene terephthalate.

[0123] [Example 9] Direct conversion of plastic and tallow via FCC (using ZSM-5 catalyst) Laboratory tests of the fluid catalytic cracking (FCC) process were carried out using a stable blend of plastic and biofeedstock (Examples 3-2, 3-4, and 6-1) and an FCC catalyst made of ZSM-5 zeolite, and the results are summarized in Table 10.

Table 10

[0124] The results in Table 10 show that blends of waste plastics and bio-based raw materials (tallow and soybean oil) are well-converted over ZSM-5-containing FCC catalysts. Similar to co-processing with palm oil, the ZSM-5 catalyst showed a very high conversion rate of over 95 wt% of the plastic / bio-based raw material blend under typical FCC process conditions (Examples 9-1 to 9-4). Due to the high conversion rate, the yields of LCO and HCO are very low. In all these cases, very high LPG and aromatic yields are obtained, indicating that this process can be used to produce raw materials for polymer and chemical manufacturing without using petroleum resources.

[0125] Adding 10 wt% of polyethylene or polypropylene plastic to tallow caused only slight changes in the performance of the FCC unit in terms of conversion rate and the yields of dry gas and coke. This suggests that co-processing of waste plastics and bio-based raw materials is easily feasible (Examples 9-1 vs. 9-2 and 9-3). Different from the case of palm oil shown in Example 7-2, blending 10 wt% of low-density polyethylene (Plastic A) and polypropylene (Plastic C) with tallow did not show a synergistic effect on LPG yield and aromatic yield. The LPG yield (36.5 wt% vs. 35.5 - 36.4 wt%) and the total aromatic yield (80.6 wt% in the gasoline fraction vs. 80.3 - 80.6 wt%) were the same as in the case of plastic co-feed.

[0126] Blending 10 wt% of plastic with tallow and soybean oil (Example 9-4) also showed consistent results of high LPG and aromatic compound production and high para-xylene selectivity.

[0127] The high yields of LPG and aromatics shown in Table 10 indicate again that the ZSM-5 catalyst prepared with medium pore zeolite is a favorable catalyst for the production of LPG olefins and aromatic compounds from the blend of plastic and bio-based raw materials (such as tallow). When using the ZSM-5 catalyst, the xylene produced in this process is substantially paraxylene, and the paraxylene selectivity is about 65 - 67% (ratio to the total xylene production).

[0128] [Example 10] Direct conversion of plastic and tallow via FCC (using USY catalyst) Laboratory tests of the fluid catalytic cracking (FCC) process were carried out using a stable blend of plastic and tallow bio-based raw materials (Examples 3-2, 3-4, and 6-1), and an FCC catalyst made of USY zeolite. The results are summarized in Table 11.

Table 11

[0129] The results in Table 11 show that the blend of waste plastic and bio-based raw materials (tallow and soybean oil) is well-converted with the USY-containing FCC catalyst. The overall conversion rate of the blend is 85 - 87% under typical FCC process conditions (Examples 10-1 to 10-4). In all these cases, a low dry gas yield (undesirable product) and high yields of LPG, gasoline, and LCO (desirable products) are obtained, indicating that this process can be used for the simultaneous production of raw materials for chemical manufacturing and premium fuels without using petroleum resources.

[0130] Even when 10 wt% of plastic was added to tallow, only slight changes occurred in the performance of the FCC unit in terms of the conversion rate and the yields of dry gas and coke. This indicates that the co-processing of waste plastics and bio-based raw materials can be easily carried out (Examples 10-1, 10-2, and 10-3). When 10 wt% of low-density polyethylene (Plastic A) or polypropylene (Plastic C) was blended with tallow, the LPG yield slightly increased (20.1 wt% vs. 21.6 - 22.6 wt%), but had only a slight effect on the yields of other products: gasoline yield (44.6 wt% vs. 43.6 - 44.3 wt%), LCO (10.5 wt% vs. 10.2 - 11.0 wt%), and HCO yield (3.5 wt% vs. 3.2 - 3.3 wt%). No decrease in the gasoline octane number was observed with the co-feed of polyethylene, and a 2-point increase in the gasoline octane number was confirmed with the co-feed of polypropylene (88.0 vs. 87.9 vs. 92.3).

[0131] These results indicate that the USY catalyst made of large-pore zeolite is a preferred catalyst for simultaneously producing chemical raw materials and premium renewable fuels.

[0132] As used in this disclosure, the words "comprises" or "comprising" are intended as open-ended transitional terms meaning 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.

[0133] All patents and publications referenced in this specification are incorporated herein by reference to the extent not inconsistent with this specification. It will be understood that the specific structures, functions, and operations of the above-described embodiments are not necessary for practicing the present invention and are merely included in the description to complete exemplary embodiments or multiple embodiments. Further, it will be understood that the specific structures, functions, and operations described in the above-referenced patents and publications can be implemented in combination with the present invention, but they are not essential for its implementation. Therefore, it is 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.

Claims

1. A process for converting waste plastics into recycling for polyethylene polymerization, comprising: (a) selecting waste plastics containing polyethylene and / or polypropylene; (b) preparing a blend of a bio-based material and the selected waste plastics, wherein the blend contains 20 wt% or less of the selected waste plastics; (c) passing the blend through an FCC unit at a temperature exceeding the melting point of the waste plastics in the blend. (d) recovering a C ３ olefin / paraffin mixture from the FCC unit; (e) passing the C ３ olefin / paraffin mixture through a steam cracker to produce ethylene The above process.

2. The process according to claim 1, wherein gasoline and heavy fractions are recovered from the FCC unit.

3. The process according to claim 1, wherein the blend in (b) is a high-temperature homogeneous blend of waste plastics and bio-oil.

4. The process according to claim 1, wherein the blend in (b) is a stable blend of waste plastics and bio-oil.

5. The process according to claim 1, wherein ethylene is polymerized into polyethylene.

6. The process according to claim 1, wherein the waste plastics selected in (a) include plastics from classification groups 2, 4, and / or 5.

7. The process according to claim 2, wherein the gasoline recovered from the FCC unit is sent to a gasoline blend pool.

8. C ４ The process of claim 1, wherein the stream and heavy fraction are recovered from the FCC unit distillation column and further processed at a refinery to obtain clean gasoline, diesel, or jet fuel.

9. The process according to claim 1, wherein the volumetric flow rate of the blend flowing into the FCC unit in (c) constitutes up to about 100 vol% of the total hydrocarbon flow rate flowing into the FCC unit.

10. The process according to claim 1, wherein the volumetric flow rate of the blend flowing into the FCC unit in (c) constitutes up to about 50 vol% of the total hydrocarbon flow rate flowing into the FCC unit.

11. The process according to claim 10, wherein the blend flow rate constitutes up to about 25 vol% of the total flow rate flowing into the FCC unit.

12. The process according to claim 1, wherein the blend of the bio-based material and the selected waste plastics in (b) is prepared by heating a mixture of the waste plastics and the bio-based material to a temperature exceeding the melting point of the plastics and then cooling the blend to a temperature below the melting point of the waste plastics.

13. The process according to claim 1, wherein the bio-based material contains triglycerides and / or fatty acids.

14. The process according to claim 1, wherein the bio-based material contains plant-derived oils and / or animal-derived fats and oils.

15. The process according to claim 14, wherein the plant-derived oil comprises palm oil, canola oil, corn oil, soybean oil, or a mixture thereof.

16. The process according to claim 14, wherein the bio-based feedstock comprises tallow, lard, schmalz, fish oil, or a mixture thereof.

17. The process according to claim 1, wherein the bio-based feedstock comprises palm oil, tallow, soybean oil, or a mixture thereof.

18. The process according to claim 1, wherein the bio-based feedstock comprises pyrolysis oil from biomass.

19. The process according to claim 1, wherein the bio-based feedstock comprises a bio-based feedstock or a mixed bio-based feedstock having an iodine value of 95 or less.

20. The process according to claim 19, wherein the iodine value is 91 or less.

21. The process according to claim 19, wherein the bio-based feedstock comprises a mixture of a bio-oil or fat having an iodine value of 70 or less and a bio-oil or fat having an iodine value exceeding 70.

22. The process according to claim 1, wherein a petroleum feedstock stream containing LCO or gasoline is added to reduce the blend viscosity.

23. The process according to claim 1, wherein the blend passed through the FCC unit is mixed with a petroleum-based feedstock.

24. The process according to claim 23, wherein the petroleum feedstock constitutes 1 to 50 vol% of the mixed blend.

25. The process according to claim 24, wherein the petroleum-based feedstock comprises atmospheric gas oil, vacuum gas oil (VGO), atmospheric residue, petroleum-derived oil, petroleum-based materials, and / or heavy fractions recovered from refining operations.

26. The process according to claim 24, wherein the petroleum-based feedstock comprises light cycle oil (LCO), heavy cycle oil (HCO), FCC naphtha, gasoline, diesel, toluene, and / or a petroleum-derived aromatic solvent.

27. The process according to claim 1, wherein the blend passed through the FCC unit is mixed with a recycle stream, thereby reducing the viscosity of the blend.

28. The process according to claim 1, wherein ethylene is polymerized to produce polyethylene.

29. Polyethylene produced from a blend of a bio-based feedstock and waste plastic according to the process of claim 28.

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