Use of blends of waste plastics and bio-based raw materials for the preparation of chemical substances

Abstract

Provided is a continuous process for converting waste plastics into recycling for the production of chemical substances. This process includes a step of selecting waste plastics containing polyethylene and / or polypropylene, and a step of preparing a stable 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 a conversion unit. Useful chemical substances including C3 and C4 olefins and aromatics are recovered.

Description

Technical Field

[0001] (Cross - reference to related applications) This application claims priority to U.S. Provisional Application No. 63 / 359,598, 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, there has been a rapidly growing movement in the industry to produce chemicals and fuels from renewable resources such as biomass feedstocks. With the increasing demand for liquid transportation fuels, the depletion of "easy oil" (crude oil that is easily accessible and recoverable), and the strengthening of restrictions on the carbon footprint of such fuels, it has become increasingly important to develop routes for efficiently producing liquid transportation fuels from alternative resources. Biomass - based feedstocks such as those containing triglycerides (e.g., fats and oils derived from plants, animals, and microorganisms) are important feedstocks for non - fossil - fuel - derived energy sources because they are available on a large scale. Biomass provides a renewable carbon source. Despite ongoing research and development in the manufacturing processes of liquid fuels, there is still a need to provide improved processes for producing low - carbon - footprint hydrocarbons useful as liquid fuels or fuel blend components.

[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, the world's plastic waste volume is estimated to reach 460 million tons per year by 2030 if the current trajectory continues.

[0004] Disposable plastic waste is becoming an increasingly important environmental issue. At present, there seem to be few options for recycling waste plastics such as polyethylene and polypropylene 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. Most (over 80%) are incinerated, landfilled, or discarded.

[0005] The current method of chemical recycling via pyrolysis cannot have a major impact on the plastics industry. In current pyrolysis operations, poor-quality fuel components (products in the naphtha and diesel ranges) are produced, but the quantity is so small that these products can be blended into the fuel supply. However, to address environmental issues, such simple blending cannot continue in order to recycle a very large amount of waste polyethylene and waste polypropylene. The products as they come from the pyrolysis unit are of such poor quality that they cannot be blended in large quantities into transportation fuels.

[0006] Worldwide, the recycling and upcycling of plastic waste have attracted great interest in order to conserve resources and the environment. The mechanical recycling of plastic waste is quite limited because the types, properties, additives, and contaminants of the collected plastics are different. Usually, the quality of recycled plastics deteriorates. Chemical recycling into starting materials or value-added chemical substances has emerged as a more desirable method.

[0007] However, in order to industrially and massively chemically recycle disposable plastics and reduce their environmental impact, a more robust process is required. 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, 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

[0008] Provided is a process for recycling plastic waste by converting it into valuable chemicals and fuels. This process includes a step of selecting waste plastics to blend with bio-based raw materials, and the bio-based raw materials can include a mixture of bio-based raw materials. The blend can then be fed to a catalytic conversion unit for conversion. This conversion process produces clean (clean) monomers, fuels, and chemical intermediates (including aromatics).

[0009] In one embodiment, the blend contains about 20 wt% or less of the selected waste plastics. In another embodiment, the blend is fed to a purification conversion unit such as an FCC unit.

[0010] The term "bio" refers to biochemical and / or natural chemicals that exist in nature. Thus, bio feedstock or bio-oil will include such natural chemicals. Preferred starting bio-based raw materials 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.

[0011] Integrating this process into an oil refinery is an important aspect of this process and enables the realization of a circular economy with respect to plastic recycling. Thus, the blend is passed through the refining FCC unit. The blend is passed at a temperature above its pour point so that it can be pumped to the refining 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. This C3 olefin / paraffin mixture can be used to produce polyethylene and polypropylene. However, other chemical streams can also be recovered from the FCC unit to produce important and valuable chemicals.

[0012] A refinery generally has its own hydrocarbon feed flowing through refinery units. An important aspect of this process is that it does not adversely affect the operation of the refinery. The refinery still has to produce valuable chemicals and fuels. Otherwise, integrating this process into an oil refinery cannot be said to be a feasible solution. Therefore, the flow rate needs to be carefully monitored.

[0013] The volume of the waste plastic / biomass feed blend flowing into the refining unit can be configured as any practical or acceptable volume percentage (vol%) of the total flow into the refining unit. Generally, the blend flow rate 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 refining flow rate). In one embodiment, the blend flow rate is an amount up to about 50 vol% of the total flow rate (i.e., the refining flow rate plus the blend flow rate).

[0014] Among other factors, it has been found that the blend of waste plastics and bio-based raw materials can be adjusted, and this blend can be made stable enough to be stored or transported as required. Further, this blend can be converted into value-added chemicals or fuels in a conversion unit. Using waste plastics and bio-based raw materials together significantly improves the environmental aspects of the conversion process. Additionally, by incorporating the conversion unit as part of a refinery operation, waste plastics can be recycled efficiently and effectively while complementing the refining operations in the preparation of high-value products such as gasoline, jet fuel, base oil, and diesel. Throughout the process from recycled plastics to value-added chemicals and fuels, the plus economics is realized, and by utilizing the blend of bio-based raw materials and waste plastics, the environmental aspects of the recycling process are also enhanced.

Brief Description of the Drawings

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DETAILED DESCRIPTION OF THE INVENTION

[0022] In this process, a method is provided for recycling waste plastics such as polyethylene and / or polypropylene into valuable chemicals and fuels. 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 via chemical recycling, and these recycled and purified polymer pellets are pyrolyzed in a pyrolysis unit to produce fuels (naphtha, diesel), steam cracker feedstock, or slack wax.

[0023] Ethylene is the most produced basic building block of petrochemicals. Ethylene is produced annually in hundreds of millions of tons via steam cracking. A steam cracker uses either gaseous feedstocks (ethane, propane, and / or butane) or liquid feedstocks (naphtha or gas oil). Steam cracking is a non-catalytic cracking process carried out at very high temperatures up to 850°C.

[0024] Today, due to the inefficiency and ineffectiveness of the recycling efforts described above, only a small portion of used polyethylene products are being collected for recycling.

[0025] Polypropylene is widely used in a variety of consumer and industrial products. Polypropylene is a general-purpose plastic that has mechanical durability and high chemical resistance and is the second most widely produced plastic after polyethylene. Polypropylene is widely used in packaging, films, fibers for carpets and clothing, molded products, and extruded pipes. Today, only a small portion of used polypropylene products are being collected for recycling. This is due to the inefficiency and ineffectiveness of the recycling efforts described above.

[0026] A recycling process that returns plastic waste to clean monomers is currently available, in which waste plastic and biofeedstock are simultaneously converted in a conversion unit. The clean monomers can be used for value-added chemicals, fuels, and aromatic chemical intermediates. This process involves preparing a novel blend of waste plastic and biofeedstock. This blend is converted in a conversion unit such as a catalytic process unit.

[0027] High-quality gasoline, jet, diesel fuel, and base oil can also be produced from the waste plastic / biofeedstock blend. The fuel components are upgraded in a suitable refining unit via a chemical conversion process. The final transportation fuels and base oil produced by the integrated process are of high quality and meet the quality requirements for fuels and base oil.

[0028] Figure 1 shows a simplified process diagram of the basic case of the waste plastic pyrolysis process commonly carried out in today's industry. Generally, waste plastics are sorted together (1). The washed waste plastics 2 are 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 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 paraffin wax when cooled to ambient temperature). The wax can be separated from the heavy fraction 6 and sold in the wax market.

[0029] By using the blend of waste plastic / biomass raw material of the present invention, many advantages can be obtained for recycling compared to the pyrolysis process. In this process, the waste plastics are not pyrolyzed. Instead, the blend of biomass raw material and waste plastics is directly converted in the conversion unit.

[0030] 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 can be produced at high temperature. The homogeneous liquid blend of plastic and biomass raw material at high temperature can be directly supplied to the conversion unit.

[0031] The preferred range of plastic in the composition blend is about 1 to 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, having 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, and preferably also in an oxygen-free atmosphere.

[0032] 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.

[0033] 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 to 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, having 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, and preferably also in an inert atmosphere without oxygen.

[0034] 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.

[0035] 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 offers many advantages.

[0036] The stable blend is made from 1 - 20 wt% of plastic waste and the bio-based raw material, and the plastic is mainly polyethylene, polypropylene and / or polystyrene, and the plastic is in the form of finely dispersed micron-sized particles.

[0037] The stable blend is fed into a catalytic conversion process, in which the bio-based raw material and the waste plastic are simultaneously converted into chemical raw materials.

[0038] The significance of heating the blend to a temperature above the melting point of the plastic becomes clear when using a single plastic. However, if 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 below the melting point of all plastics that make up the blend.

[0039] By implementing these concepts, several advantages are realized.

[0040] In this process, the waste plastic is not pyrolyzed. Instead, a blend of bio-based raw material and waste plastic is prepared. Therefore, the pyrolysis step can be avoided, which results in significant energy savings.

[0041] A stable blend of plastic and bio-based raw materials can be stored for a long time at ambient temperature and normal pressure. During storage, no polymer aggregation or chemical / physical degradation of the blend is observed. This simplifies the handling of waste plastic materials during storage or transportation.

[0042] The 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 a refinery. No polymer aggregation is observed during heating.

[0043] To supply a conversion unit, the stable blend is further heated to a temperature above the melting point of the plastic, producing a homogeneous liquid blend of the bio-based raw material 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 bio-based raw materials into high-value and sustainable products with high yields.

[0044] 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 purified raw materials from waste plastics than pyrolysis processes such as pyrolysis.

[0045] The use of the waste plastic / bio-based raw material 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, 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 a pyrolysis plant is at most 70 - 80%.

[0046] 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 cracking process (different from the pyrolysis process used in pyrolysis) is used. Using the catalytic process minimizes the generation of undesirable light by-products such as methane and ethane. 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.

[0047] This process can convert 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 can produce not only polymer feedstocks (naphtha or C3 and C4 for ethylene crackers), but also high-quality gasoline, jet fuel, and diesel, and / or high-quality base oils, and furthermore, value-added chemicals (including aromatic intermediates).

[0048] By adding a purification operation to upgrade waste plastics to high-value products, the plus economics is realized throughout the process of recycled plastics. Also, by integrating this recycling process with an oil refinery operation, a more energy-efficient and effective process is achieved while avoiding the problems of the purification operation.

[0049] The integration of the refining operation 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 refining 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 refining unit using a chemical conversion process, and the final transportation fuel produced by the integrated process is of higher quality and can meet the fuel quality requirements.

[0050] Figure 2 shows a method for preparing a high-temperature homogeneous blend of plastic and biomass feedstock according to this process. This high-temperature 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, for example, as 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.

[0051] 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 biomass feedstock. 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 open air and preferably also under an inert atmosphere without oxygen.

[0052] Referring to FIG. 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 post-consumer 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 in 23, a homogeneous blend of plastic and bio-oil is recovered (25). Optionally, a filtration device (not shown) can be added 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 refinery feedstocks.

[0053] FIG. 3 shows a method for preparing a stable blend of plastic and oil for use in this process. The stable blend is made by a two-step process in a stable blend preparation unit. In the first step, a homogeneous liquid blend of plastic melt and bio-based raw materials is produced at high temperature. This step is the same as the high-temperature blend preparation described in FIG. 2. 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 above 0.93 g / cc) are mainly used, for example, as 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 preparing the high-temperature homogeneous 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. 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.

[0055] 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. It is further cooled to a low temperature, preferably ambient temperature, to produce a stable blend of plastic and oil.

[0056] The stable blend is known to be a close physical mixture of plastic and bio-based raw material. The plastic is in a "de-aggregated" state. The plastic maintains a finely dispersed state of the solid particles in the bio-based raw material at a temperature lower than the melting point of the plastic, especially at ambient temperature. The blend is stable and easy to store and transport. At the refinery, the stable blend can be heated above the melting point of the plastic in a preheater to produce a homogeneous liquid blend of plastic and bio-based raw material at a high temperature. This high-temperature liquid blend can then be fed to the refining unit alone or as a co-feed together with a conventional refining feedstock.

[0057] Figure 3 shows further details of the preparation of a 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 biofeedstock 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. During mixing, any diluent 26 can be added. 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 inert atmosphere free of oxygen. 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.

[0058] Next, the high-temperature 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-oil. During mixing and cooling, any diluent 103 can be added. The cooling is usually 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 of plastic / oil blend 105, which is then fed to a purification conversion unit 27.

[0059] Preferred plastic starting materials for this process are sorted waste plastics mainly containing polyethylene and polypropylene (plastic recycling classification types 2, 4, and 5). The pre-sorted waste plastics are washed, shredded or pelletized, and supplied to the blend preparation unit. Figure 4 shows the type classification of plastics regarding the recycling of waste plastics. Classification types 2, 4, and 5 are high-density polyethylene, low-density polyethylene, and polypropylene, respectively. 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.

[0060] To minimize contaminants such as N, Cl, S, etc., it is very important to properly sort the 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) needs to 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 needs to be sorted to less than 20%, preferably less than 10%, and most preferably less than 5%.

[0061] Washing of the waste plastics can remove metal contaminants such as sodium, calcium, magnesium, aluminum, etc., and non-metal contaminants from other waste sources. 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, and iodides. Residual metals, non-metal contaminants, and halides need to be removed to less than 50 ppm, preferentially less than 30 ppm, and most preferentially less than 5 ppm.

[0062] The term "bio" refers to biochemical and / or natural chemical substances existing in nature. Therefore, bio feedstock or bio-oil will contain such natural chemical substances. 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), and mixtures thereof. In one embodiment, the bio feedstock can include biomass pyrolysis oil prepared by pyrolyzing bio feedstock materials.

[0063] The most preferred bio feedstocks 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 of iodine (in grams) consumed by 100 g of the substance. The higher the numerical 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.

[0064] Bio feedstocks 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 feedstock mixture consisting of a bio feedstock with a low iodine number (≤70) and a bio feedstock with a high iodine number (>70) can form a stable blend with plastics. Bio feedstock mixtures with an iodine number of about 95 or less have been found to form a stable blend with plastics. In one embodiment, the mixture of bio feedstocks has an iodine number of 91 or less.

[0065] Furthermore, the blend of plastic and bio-based raw 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, to facilitate handling or 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 products (such as naphtha and LCO) can also be recycled to the blend. In one embodiment, no petroleum raw material is used, and only bio-based raw materials are used for making the blend and mixing with the blend.

[0066] Without wishing to be bound by theory, the prepared stable blend is a close physical mixture of plastic and bio-based raw material for the catalytic conversion unit. This process produces a stable blend of bio-based raw material 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 bio-based raw material at high temperature, and then this high-temperature liquid blend is fed to the conversion unit. Thereafter, both the bio-based raw material 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.

[0067] 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 in the presence of a catalyst using co - conversion of plastic and biofeedstock. 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 plastics.

[0068] The fluid catalytic cracking process is a preferred mode of catalytic conversion of a stable blend. The yield of undesirable 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 between plastic and biofeedstock during the conversion process.

[0069] To maximize the conversion to the desired products, the selection of an appropriate catalyst is essential. ZSM - 5 - based FCC catalysts have been found to be particularly effective in producing LPG olefins and aromatic compounds from blends of plastic and biofeedstock. It has also been found that xylene products rich in para - xylene can be selectively produced in high yields. When using a ZSM - 5 catalyst, the xylene produced in this process is mainly para - xylene, and the para - xylene selectivity is about 60 - 70%. Para - xylene is the most desirable xylene isomer for the production of polyethylene terephthalate polymers. ZSM - 5 is a zeolite with a medium pore diameter of 10 - membered rings. Catalysts containing other medium - pore zeolites such as ZSM - 11, ZSM - 23, ZSM - 25, ZSM - 48, SSZ - 32, SSZ - 91 can also be suitably used to convert blends of plastic and biofeedstock to produce LPG olefins and aromatic compounds.

[0070] The most commonly used FCC catalysts are those based on macroporous faujasite, USY, or REY zeolites. Y zeolite-containing catalysts exhibit excellent cracking activity towards heavy molecules in conventional petroleum feedstocks such as VGO. USY-containing FCC catalysts have been found to produce more LCO from blends of plastics and biofeedstocks. USY is a 12-ring macroporous zeolite. Catalysts containing other large-pore zeolites such as ZSM-12, Beta, SSZ-24, SSZ-26, SSZ-33, SSZ-60, SSZ-65, SSZ-70, SSZ-81, SSZ-82, and SSZ-111 can be used to convert blends of plastics and biofeedstocks to simultaneously produce sustainable fuels and chemical intermediates.

[0071] A stable blend of plastic and biofeedstock enables more efficient recycling of waste plastics and truly circular and sustainable production of plastics and chemicals. This is much more energy-efficient than current pyrolysis processes and enables recycling with a lower carbon footprint. The improved process allows for the efficient conversion of waste plastics into unused-quality polymers or valuable chemicals and fuels, enabling the establishment of a much larger circular economy.

[0072] A dedicated conversion unit for converting blends of plastics and biofeedstocks produces sustainable low-carbon chemical intermediates and fuels without using petroleum feedstocks.

[0073] Alternatively, a blend of plastic and biofeedstock can be supplied to a petroleum refining conversion unit for co-processing with petroleum-based oils. Refining conversion units such as fluid catalytic cracking (FCC) units, hydrocracking units, and hydrotreating units are preferred for the simultaneous conversion of plastics, biofeedstocks, and petroleum-based oils.

[0074] In such cases, the refinery generally has a supply of its own hydrocarbons flowing through the refining unit. For example, the hydrocarbon source can be VGO. The volume of the blend stream flowing into the refining unit such as the FCC unit can constitute any practical or acceptable volume % (vol%) of the total stream flowing into the refining unit (total flow rate). Generally, for practical reasons, the flow rate of the blend 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 flow rate of the blend is an amount up to about 100 vol% of the total flow rate. The volume % (vol%) of the blend also varies depending on the ultimately desired product. In the case of aromatic compounds and chemicals centered on xylene, the flow % of the blend can be much higher, even if it is 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 excellent results and being an acceptable 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 occupy up to 100 volume % of the feed amount to the refining unit.

[0075] Figure 5 shows an embodiment of the integrated process of the present invention in which the blend is sent to a fluid catalytic cracking (FCC) unit. In Figure 5, the same numbers corresponding to the numbers in Figures 2 and 3 refer to the same items / units. As shown, the blend is prepared at 25 and then passed through 26 to the FCC conversion unit 27. The blend can also be mixed with co-feed vacuum gas oil (VGO) or not. The blend is generally heated to a temperature above the melting point of the plastic before being passed through the FCC conversion unit 27.

[0076] In Figure 5, the decomposition of the plastic / bio high-temperature blend generates liquefied petroleum gas (LPG) of C3 and C4 olefins / paraffins streams 31 and 32, as well as naphtha 33 and heavy fraction 30 in the FCC unit 27, either alone or in combination with co-fed petroleum feedstock (co-fed petroleum supply). The C3 olefin / paraffin mixed stream of propane and propylene is sent to a propane / propylene splitter (PP splitter), by which it can be separated to produce pure streams of propane and propylene.

[0077] The C4 stream 32 and other hydrocarbon product streams (such as heavy fraction 30) from the FCC unit 28 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 through the gasoline pool 35 or further upgraded before being sent to the gasoline pool (not shown).

[0078] A portion of the naphtha 33 can be sent for chemical production. For example, the naphtha can be sent to an aromatic separation unit 60. From 60, benzene, toluene, xylene, and ethylbenzene can be recovered and sent to intermediate processing 62 and / or other chemical production 63. From the intermediate processing 62 of the chemical substances, the resulting chemical substances can be sent to a polymerization process unit 64. Based on the recovered and polymer-fed processed chemical substances, polymers such as polyethylene terephthalate and polystyrene can be produced. For example, paraxylene can be easily used to prepare polyethylene terephthalate (PET).

[0079] LPG and naphtha can be recovered and supplied to a steam cracker for producing ethylene, and then chemicals derived from ethylene such as polyethylene, ethylene oxide, and polyalphaolefin can be produced. C3 olefins in LPG can be recovered and propylene and / or propylene oxide can be produced. C4 olefins in LPG can be recovered and low-density copolymers can be produced (the process scheme is not shown in the figure).

[0080] In one embodiment, the conversion unit 27 is not within the refinery and only the blend of biofeedstock / plastic is sent to the unit. In that case, the recovery of naphtha for producing aromatic compounds will be emphasized.

[0081] FIG. 6 shows an embodiment of the integrated process of the present invention in which the blend is sent to the hydrocracking unit 77. In FIG. 6, the same numbers corresponding to the numbers in FIGS. 2, 3, and 5 refer to the same items / units. As shown, the selected waste 21 is washed (22) and then passed through a blend preparation unit 23 where the plastic and the refined feedstock 24 are blended to produce a high-temperature blend of plastic and oil 25. To this blend, a petroleum refining feedstock such as vacuum gas oil (VGO) 20 is added as needed. If the plastic / oil blend is still hot (25 in FIG. 2), it can be immediately mixed with the co-feed oil 20. However, if the plastic / oil blend needs to be heated for storage or transportation (29 in FIG. 3), the blend is generally heated to a temperature above the melting point of the plastic, for example in a preheater, before mixing with the co-feed VGO oil. This homogeneous plastic / bio-oil blend is sent to the refinery's hydrocracking unit 77 regardless of the presence or absence of a refinery / hydrocarbon stream such as VGO oil 26. In another embodiment, the heated blend and the refinery / feedstock oil co-feed are each sent directly but separately to the hydrocracking unit.

[0082] Any suitable hydrocracking operation can be carried out. The catalyst in the hydrocracking unit can be selected from any known hydrocracking catalyst. The hydrocracking conditions generally include a temperature in the range of 300 °C to 485 °C, a molar ratio of hydrogen to hydrocarbon of 1 to 100, a pressure in the range of 30 to 350 bar, and a liquid hourly space velocity (LHSV) in the range of 0.1 to 10. Larger molecules are decomposed into smaller molecules in the hydrocracking reactor. Hydrocracking catalysts usually include various combinations of macroporous zeolites such as USY and Group VI and VIII base metals such as nickel, cobalt, molybdenum, and tungsten, which are finely dispersed on an alumina or oxide support.

[0083] From the hydrocracking unit, a C3-C4 stream 30 of LPG, a clean naphtha stream 31, and a heavy fraction 28 are recovered. The heavy fraction 28 can be sent to the isomerization / dewaxing unit 29. In the isomerization / dewaxing reactor, first, the feedstock can be contacted with a hydrotreating catalyst under hydrotreating conditions in a hydrotreating zone or a guard bed to provide a hydrotreated feedstock. Hydrotreating catalysts usually include various combinations of Group VI and VIII base metals such as nickel, cobalt, molybdenum, and tungsten, which are finely dispersed on an alumina or oxide support. By contacting the feedstock with the hydrotreating catalyst in the guard bed, aromatics in the feedstock can be effectively hydrogenated, and N-containing and S-containing compounds can be removed from the feedstock, thereby protecting the hydroisomerization catalyst of the catalyst system. "Effectively hydrogenating aromatics" means that the hydrotreating catalyst can typically reduce the aromatic content in the feedstock by at least about 20%. The hydrotreated feedstock generally contains C 10+ n-paraffins and slightly branched isoparaffins, and the wax content is typically at least about 20%.

[0084] The hydroisomerization catalyst useful in this process typically contains a catalytically active hydrogenation metal. The presence of the catalytically active hydrogenation metal leads to an improvement in the product, particularly in terms of VI and stability. Typical catalytically active hydrogenation metals include chromium, molybdenum, nickel, vanadium, cobalt, tungsten, zinc, platinum, and palladium. Platinum and palladium are particularly preferred as the metals, with platinum being the most preferred. When platinum and / or palladium are used, the total amount of the active hydrogenation metal is typically in the range of 0.1 wt% to 5 wt% of the total catalyst, usually 0.1 wt% to 2 wt%. Further, the hydroisomerization catalyst usually contains medium-pore zeolites such as ZSM-23, ZSM-48, ZSM-35, SSZ-32, SSZ-91, etc. dispersed on an oxide support.

[0085] The refractory oxide support can be selected from the oxide supports conventionally used in catalysts, including silica, alumina, silica-alumina, magnesia, titania, and combinations thereof.

[0086] The conditions within the isomerization / dewaxing reactor unit 29 generally include a temperature within the range of about 390°F to about 800°F (199°C to 427°C). In one embodiment, the hydroisomerization dewaxing conditions include a temperature in the range of about 550°F to about 700°F (288°C to 371°C). In a further embodiment, the temperature may be in the range of about 590°F to about 675°F (310°C to 357°C). The total pressure is in the range of about 500 to about 3000 psig (0.10 to 20.68 MPa), typically in the range of about 750 to about 2500 psig (0.69 to 17.24 MPa).

[0087] The dewaxed oil 33 can be recovered from the isomerization / dewaxing unit 29, and this oil can be used as base oil. This oil can also be sent to the hydrofinishing unit 34 to prepare the premium base oil 35. In the hydrofinishing unit 34, as is known in the art, hydrofinishing can be carried out in the presence of a hydrogenation catalyst. The hydrogenation catalyst used for hydrofinishing can include, for example, platinum, palladium, or a combination thereof on an alumina support. The hydrofinishing can be carried out at a temperature in the range of about 350°F to about 650°F (176°C to about 343°C) and a pressure in the range of about 400 psig to about 4000 psig (2.76 MPa to 27.581 MPa). The hydrofinishing for the production of lubricating oil is described, for example, in U.S. Patent No. 3,852,207, the disclosure of which is incorporated herein by reference.

[0088] The clean naphtha stream 31 and / or the clean LPG stream 30 from the hydrocracker, and the clean LPG stream 32 and / or the clean naphtha stream 36 from the isomerization unit 29 can be sent for chemical production as shown in FIG. 5. For example, the naphtha can be sent to the aromatics separation unit 60. From 60, benzene, toluene, xylene, and ethylbenzene can be recovered and sent to the intermediate treatment 62 and / or other chemical production 63. From the intermediate treatment 62 of the chemical substances, the resulting chemical substances can be sent to the polymerization process unit 64. Based on the recovered and treated chemical substances sent for polymerization, polymers such as polyethylene terephthalate and polystyrene can be produced. For example, paraxylene can be easily used to prepare polyethylene terephthalate (PET).

[0089] LPG and naphtha can be recovered and supplied to a steam cracker for producing ethylene, and then chemicals derived from ethylene such as polyethylene, ethylene oxide, and polyalphaolefin can be produced. C3 olefins in LPG can be recovered and propylene and / or propylene oxide can be produced. C4 olefins in LPG can be recovered and low-density copolymers can be produced (the process scheme is not shown in the figure). The merits of circular economy and an effective and efficient recycling campaign are realized by this integrated process.

[0090] The following examples are provided as illustrations of the blends and processes of the present invention and are not intended to be limiting.

Example

[0091] [Example 1] Characteristics of Plastic Samples and Bio-based Raw Materials 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 characteristics are summarized in Table 1.

Table 1

[0092] Bio-based raw materials used for preparing blends with plastic melts include palm oil, tallow, and soybean oil, and their characteristics are shown in Table 2.

Table 2

[0093] Thermogravimetric analysis (TGA) was performed on Plastic A (LDPE) and Plastic C (polypropylene), and it was confirmed 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.

[0094] [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 - raw material #1).

[0095] The following procedure was used. At ambient temperature, palm oil (a 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 raised 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 had dissolved, the stirred solution was held at the final temperature for an additional 30 minutes for blends using LDPE and plastic C polypropylene, and 60 minutes for blends using HDPE and plastic D polypropylene. Then, 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.

[0096] To evaluate the need for material handling, the pour point (by ASTM D5950-14) and viscosity (by ASTM D445) of the blend were measured. Further, the content of high-temperature heptane-insoluble substances 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 on the undissolved plastics in the blend.

[0097] The stability of the material 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.

[0098] Table 3 below summarizes the list of prepared samples and their properties.

Table 3

[0099] The pour point and viscosity values are used as guidelines for equipment selection and operating procedures. The blend prepared by adding plastic shows a moderate increase in pour point and viscosity compared to the pure bio-based case. These changes can be accommodated with minor or no changes in typical refining operation equipment. The blend tank is heated to a temperature above the pour point to change 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 transport by a pump, discharge by gravity, or transfer by a pressure difference.

[0100] The stable blend remains a physical mixture at temperatures up to 80°C. The plastic was separated from the blend using the hot heptane insolubility test. At 80°C, all the wax in the palm oil 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 substance is derived from the undissolved plastic filtered through a 0.8-micron membrane filter. The amounts recovered as solid substances in Example 2-2 and Example 2-4 indicate that the heptane-insoluble solids are 7.6 wt% and 7.8 wt%, respectively, which is almost the same as the amount of plastic added for blend preparation. Since the recovered amount is 2.2 wt% - 2.4 wt% less, it is suggested that the blend may contain very fine submicron-sized particles. 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.

[0101] [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 the tallow raw material (Biofeedstock #2).

[0102] The procedure described in Example 2 was used for these blend preparations.

Table 4

[0103] The blends 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 the palm oil shown in Example 2.

[0104] The weight percentage of heptane-insoluble substances recovered as solids is in good agreement with the amount of plastic added to the blend preparation. In the case of the base-case tallow (Example 3-1), only 0.04 wt% of heptane-insoluble matter is contained, while in the stable blends (Examples 3-2 and 3-4), 7.7 wt% and 8.6 wt% of heptane-insoluble solids are contained, 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 contains 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 an 80 °C blend, and that most of the plastic particles can be separated by a 0.8 micron filter.

[0105] [Example 4] Preparation of a Blend of Soybean Oil and Plastic (Comparative Example) An attempt was made to prepare a blend of soybean oil (biofeedstock #3) and plastic using the procedure described in Example 2 and plastic pellets (Plastics A - D). Surprisingly, soybean oil and plastic did not form a homogeneous liquid melt at high temperature even when heated together in the same way as in the case of palm oil or tallow. When the mixture was heated above the melting point of the plastic, the pellets softened and lost their shape. However, instead of forming a homogeneous liquid as in the other cases, the plastic melt formed a separate liquid phase from the soybean oil (SBO). Upon cooling, the plastic phase aggregated to form large plastic solid pieces. The reason for this is thought to be that the unsaturation of SBO is much higher. This is also evident from the lower H / C ratio compared to tallow and palm oil, and also from the measured iodine value. This also explains why most petroleum raw materials and highly saturated oils and fats determined by the iodine value can easily dissolve plastics.

Table 5

[0106] [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 biofeedstock) was prepared. Using the mixed biofeedstock, plastic pellets (Plastics A and C) were added to a 1:1 mixture of palm oil and soybean oil (Biofeedstock #1 and Biofeedstock #3), and a blend of palm oil, soybean oil, and plastic was successfully prepared. Therefore, soybean oil can be used as a component of the mixed biofeedstock. The stable blend showed a good shelf life and showed no change for several months. These results indicate that soybean oil can also be used as a biofeedstock for preparing a stable blend with plastic by reducing the degree of unsaturation using soybean oil together with another biofeedstock.

[0107] This test also shows an acceptable iodine value for successfully producing a stable blend of plastic and biofeedstock. 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 biofeedstocks for preparing a stable blend with plastic as long as the overall degree of unsaturation of the mixed biofeedstock is 95 or less, preferably 91 or less in iodine value.

Table 6

[0108] [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 mixed biofeedstock, plastic pellets (Plastics A and C) were added to a 1:1 mixture of tallow and soybean oil (Biofeedstock #1 and Biofeedstock #3), and a blend of tallow, soybean oil, and plastic was successfully prepared. The stable blend showed a good shelf life and showed no change for several months. These results again indicate that soybean oil can also be used as a biofeedstock for preparing a stable blend with plastic by reducing the degree of unsaturation using soybean oil together with another biofeedstock.

[0109] This test also shows the iodine value that can be tolerated in order 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

[0110] 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 medium-pore zeolite with a 10-membered ring), and the other was a USY-containing FCC catalyst made of USY (a medium-pore zeolite with a 12-membered ring). Three bio-based raw materials, palm oil, soybean oil, and tallow, were used.

[0111] (Catalyst) The catalytic cracking experiment was conducted 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 conducted 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 performed 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.

[0112] The gaseous products, mainly hydrocarbons from C1 to C7, were analyzed by 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 in the gas products when bio-based raw materials such as soybean oil, tallow, or palm oil were decomposed. 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 by simulated distillation GC (Agilent 6890) using the ASTM D2887 method. The liquid products were divided 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 obtain the total gasoline. The light components (C 5- ) in the liquid products were also subtracted from the liquid products and re-added to the C3 and C4 species using an empirical distribution. The material balance was 98% to 102% in most experiments.

[0113] For the gasoline portion of the liquid products, detailed hydrocarbon analysis (DHA) was also performed 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 performed on the gasoline portion of the gaseous products. However, the DHA results still provided valuable information for evaluating the characteristics of the (catalytic) cracking products.

[0114] [Example 7] Direct conversion of plastics and palm oil via FCC (using 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

[0115] 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 over the ZSM-5-containing FCC catalyst. Surprisingly, the medium-pore 10-membered 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 yields of LPG and aromatics are obtained, indicating that this process can be used to produce raw materials for polymer and chemical manufacturing without using petroleum resources.

[0116] 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 conversion rate and 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 total aromatics yield (76 wt% vs. 81 wt% in the gasoline fraction) were observed. The significant increase in the LPG yield and aromatics yield from the plastic-containing blend was completely unexpected. This clearly shows that the synergistic effect of the bio-based raw material and plastic blend increases the yields of LPG and aromatics.

[0117] 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.

[0118] These results indicate that the ZSM-5 catalyst made of medium-pore zeolite is a preferred catalyst for the production of LPG olefins and aromatic compounds when converting bio-based raw material / plastic blends.

[0119] 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.

[0120] 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 the 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.

[0121] 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 small.

[0122] [Example 8] Direct conversion of plastic 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 plastic 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

[0123] 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 of 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 co-production of raw materials for chemical manufacturing and premium renewable fuels without using petroleum resources.

[0124] 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). Blending 10 wt% of low-density polyethylene (Plastic A) with palm oil also had 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).

[0125] Blending 10 wt% of plastics with palm oil and soybean oil (Example 8-3) also showed consistent results of high LPG and gasoline production.

[0126] 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.

[0127] A portion 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.

[0128] The high yield of LPG by this process is important. LPG and LPG olefins are preferred feedstocks for the production of polyethylene and polypropylene.

[0129] 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.

[0130] [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

[0131] The results in Table 10 show that blends of waste plastics and bio-based feedstocks (tallow and soybean oil) are well-converted over the ZSM-5-containing FCC catalyst. Similar to the co-processing with palm oil, the ZSM-5 catalyst showed a very high conversion rate of over 95 wt% of the plastic / bio-based feedstock 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 were obtained, indicating that this process can be used for the production of raw materials for polymer and chemical manufacturing without using petroleum resources.

[0132] Even when 10 wt% of polyethylene or polypropylene 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 suggests that the co-processing of waste plastics and bio-based feedstocks can be easily carried out (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 the LPG yield and the 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 those in the case of plastic co-feed.

[0133] When 10 wt% of plastic was blended with tallow and soybean oil (Example 9-4), consistent results of high LPG and aromatic compound production, as well as high p-xylene selectivity, were shown.

[0134] The high yields of LPG and aromatics shown in Table 10 again indicate that the ZSM-5 catalyst made from medium pore zeolite is a favorable catalyst for the production of LPG olefins and aromatic compounds from the blend of plastic and bio-feedstock (such as tallow). When the ZSM-5 catalyst is used, the xylene produced in this process is substantially para-xylene, and the para-xylene selectivity is about 65 - 67% (ratio to the total xylene production).

[0135] [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-feedstock (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

[0136] The results in Table 11 show that the blend of waste plastic and bio-feedstock (tallow and soybean oil) is well converted by 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.

[0137] Even when 10 wt% of plastic was added to tallow, only slight changes occurred in the performance of the FCC unit in terms of conversion rate and yields of dry gas and coke. This indicates that co-processing of waste plastics and bio-based raw materials can be easily carried out (Examples 10-1, 10-2, and 10-3). When low-density polyethylene (Plastic A) or polypropylene (Plastic C) was blended with tallow at 10 wt%, the LPG yield increased slightly (20.1 wt% vs. 21.6 - 22.6 wt%), but had only a slight impact 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%). In the co-feed of polyethylene, no decrease in gasoline octane number was observed, and in the co-feed of polypropylene, a 2-point increase in gasoline octane number was confirmed (88.0 vs. 87.9 vs. 92.3).

[0138] 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.

[0139] 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 meaning excluding everything other than the recited elements, except for trace impurities.

[0140] All patents and publications referred to in this specification are hereby incorporated by reference into this specification to the extent that they are 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 the exemplary embodiments or multiple embodiments. Further, it will 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. Accordingly, 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 chemical substances, comprising: (a) selecting waste plastics containing polyethylene and / or polypropylene; (b) preparing a blend of a biofeedstock and the selected plastics, wherein the blend contains 20 wt% or less of the selected plastics; (c) passing the blend through a catalytic conversion unit. The above process.

2. A continuous process for converting waste plastics into aromatic compounds and chemical monomers, comprising: (a) selecting waste plastics containing polyethylene and / or polypropylene; (b) preparing a blend of a biofeedstock and the selected waste plastics, wherein the blend contains 20 wt% or less of the selected waste plastics; (c) passing the blend through a FCC unit at a temperature above the melting point of the waste plastics in the blend; (d) recovering a naphtha mixture from the FCC unit; (e) passing the naphtha mixture through an aromatic separation unit. The above process.

3. The process according to claim 2, wherein benzene, toluene, xylene, ethylbenzene, or a mixture thereof is recovered from the aromatic separation unit.

4. The process according to claim 3, wherein the recovered chemical substances are further separated and sent for polymerization.

5. The process according to claim 3, wherein p-xylene is separated and sent for polymerization to PET.

6. The process according to claim 2, wherein the catalyst in the FCC unit contains macroporous zeolite.

7. The process according to claim 2, wherein the catalyst in the FCC unit contains mesoporous zeolite.

8. The process according to claim 2, wherein the blend in (b) is a high-temperature homogeneous blend of waste plastics and bio-oil.

9. The process according to claim 2, wherein the blend in (b) is a stable blend of waste plastics and bio-oil.

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

11. C ４ The process according to claim 2, wherein the stream and the heavy fraction are recovered from the FCC unit distillation column and further processed at a refinery to obtain clean gasoline, diesel, or jet fuel.

12. The process according to claim 2, wherein the volumetric flow rate of the blend flowing into the purified FCC unit in (c) constitutes at most about 100% by volume of the total hydrocarbon flow rate flowing into the FCC unit.

13. The process according to claim 2, wherein the volumetric flow rate of the blend flowing into the FCC unit in (c) constitutes up to about 50% by volume of the total hydrocarbon flow rate flowing into the FCC unit.

14. The process according to claim 2, wherein the blend flow rate constitutes up to about 25% by volume of the total flow rate flowing into the FCC unit.

15. The process according to claim 2, wherein the blend of the bio-based feedstock and the selected waste plastic in (b) is prepared by heating a mixture of the waste plastic and the bio-based feedstock to a temperature above the melting point of the plastic and then cooling the blend to a temperature below the melting point of the waste plastic.

16. The process according to claim 2, wherein the bio-based feedstock contains triglycerides and / or fatty acids.

17. The process according to claim 2, wherein the bio-based feedstock contains plant-derived oil and / or animal-derived fats and oils.

18. The process according to claim 17, wherein the plant-derived oil contains palm oil, canola oil, corn oil, soybean oil, or a mixture thereof.

19. The process according to claim 17, wherein the bio-based feedstock contains tallow, lard, schmalz, fish oil, or a mixture thereof.

20. The process according to claim 2, wherein the bio-based feedstock contains palm oil, tallow, soybean oil, or a mixture thereof.

21. The process according to claim 2, wherein the bio-based feedstock contains pyrolysis oil of biomass.

22. The process according to claim 2, wherein the bio-based feedstock contains a bio-based feedstock or a plurality of bio-based feedstocks having an iodine value of 95 or less.

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

24. The process according to claim 22, wherein the bio-based feedstock contains 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.

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

26. The process according to claim 2, wherein the blend passed through the FCC unit is mixed with a petroleum feedstock.

27. The process according to claim 26, wherein the petroleum feedstock constitutes 1 to 50 vol% of the blended blend.

28. The process according to claim 27, wherein the petroleum-based feedstock contains atmospheric gas oil, vacuum gas oil (VGO), atmospheric residue, petroleum-derived oil, petroleum-based materials, and / or heavy components recovered from the refining operation.

29. The process according to claim 27, wherein the petroleum-based feedstock comprises light cycle oil (LCO), heavy cycle oil (HCO), FCC naphtha, gasoline, diesel, toluene, and / or an aromatic solvent derived from petroleum.

30. The process according to claim 2, wherein the blend passed through the FCC unit is mixed with a recycle stream, thereby reducing the viscosity of the blend.

31. The process according to claim 1, wherein the catalytic conversion unit comprises a hydrocracking unit.

32. The process according to claim 31, wherein the heavy fraction is recovered for the hydrocracking unit and sent to an isomerization / dewaxing unit.

33. The process according to claim 32, wherein the dewaxed oil is recovered from the isomerization / dewaxing unit and further processed into premium base oil in a hydrofinishing unit.

34. Chemicals, fuels, and base oils produced from a blend of biofeedstock and waste plastics according to the process of claim 1.

35. Chemicals, fuels, and base oils produced according to the process of claim 1.

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