Use of blends of waste plastics and biological feeds for cyclic economic polypropylene production

Abstract

A continuous process for converting waste plastic to a regenerant for polypropylene polymerization is provided. The method includes selecting waste plastic containing polyethylene and / or polypropylene and preparing a blend of the biofeedstock and the selected plastic. The amount of plastic in the blend comprises no more than 20% by weight of the blend. And introducing the blend into an FCC (Fluid Catalytic Cracking) device. A liquefied petroleum gas (LPG) olefin / paraffin mixture and naphtha are recovered from the FCC unit and can be forwarded to produce polypropylene.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to U.S. Provisional Application No. 63 / 359,588, filed on July 8, 2022, the complete disclosure of which is incorporated herein by reference in its entirety. Background Art

[0003] As part of efforts to reduce global warming, industry is experiencing rapid growth in the production of chemicals and fuels from renewable sources such as biofeedstocks or bio-oils.

[0004] On the other hand, the world has seen extremely rapid growth in plastic production. According to the European Plastics Market Research Group, world plastic production 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 global plastic waste volume is estimated to be 460 million tons / year by 2030.

[0005] Single-use plastic waste has become an increasingly important environmental issue. Currently, there seem to be few options for recycling polyethylene and polypropylene waste plastics into value-added chemicals and fuel products. Currently, only a small amount of polyethylene and polypropylene is regenerated by chemical regeneration, where recycled and clean polymer pellets are pyrolyzed in a pyrolysis unit to produce fuels (naphtha, diesel), stream cracker feeds or oily waxes. Most (greater than 80%) are incinerated, landfilled or discarded.

[0006] The current method of chemical regeneration by pyrolysis cannot make a big impact on the plastics industry. Current pyrolysis operations produce poor quality fuel components (naphtha and diesel range products), but in small enough quantities that these products can be blended into the fuel supply. However, if very large volumes of waste polyethylene and polypropylene are to be regenerated to address environmental issues, this simple blending cannot continue. The products produced by pyrolysis units are of too poor quality to be blended in transportation fuels in large quantities.

[0007] Methods for converting waste plastics into hydrocarbon lubricants are known. For example, U.S. Pat. No. 3,845,157 discloses the cracking of waste or virgin polyolefins to form gaseous products such as ethylene / olefin copolymers, which are further processed to produce synthetic hydrocarbon lubricants. U.S. Pat. No. 4,642,401 discloses the production of liquid hydrocarbons by heating powdered polyolefin waste at a temperature of 150-500° C. and a pressure of 20-300 bar. U.S. Pat. No. 5,849,964 discloses a method in which waste plastic materials are depolymerized 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 refined into liquid fuel components using standard refining techniques. U.S. Pat. No. 6,143,940 discloses a process for converting waste plastics into heavy wax compositions. U.S. Pat. No. 6,150,577 discloses a method for converting waste plastics into lubricating oils. EP0620264 discloses a process for producing lubricating oils from waste or virgin polyolefins by thermal cracking the waste in a fluidized bed to form a waxy product, optionally with hydrotreating, followed by catalytic isomerization and fractionation to recover the lubricating oil.

[0008] Other documents related to methods 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 above patent documents are incorporated herein by reference in their entirety.

[0009] Globally, recycling or upcycling of plastic waste has gained great interest for saving resources and the environment. Due to the different types, properties, additives and pollutants in the collected plastics, mechanical regeneration of plastic waste is quite limited. Often, the recycled plastics have degraded properties. Chemical regeneration to starting materials or value-added chemicals has become a more ideal approach.

[0010] However, in order to achieve chemical regeneration of single-use plastics on an industrial scale to reduce their environmental impact, more robust methods are needed. Improved methods should establish a "circular economy" for waste polyethylene and polypropylene plastics, in which used waste plastics are effectively regenerated into starting materials for polymers or value-added chemicals or fuels. The establishment of such a circular economy while also using renewable sources such as bio-based feedstocks will even further enhance the environmental benefits of such regeneration methods. Summary of the invention

[0011] An integrated process for converting waste plastics into recyclables for polypropylene production is provided. The method includes selecting waste plastics to blend with biomass, then adding the waste plastics / biomass blend to a conversion unit and converting in the conversion unit. The conversion process produces clean monomers and aromatic chemical intermediates for propylene polymerization. In one embodiment, the blend comprises about 20 wt % or less of the selected waste plastics. In another embodiment, the blend is added to a refinery conversion unit such as an FCC unit.

[0012] The term "biological" refers to biochemicals and / or natural chemicals found in nature. Thus, a biological feedstock or bio-oil will contain such natural chemicals. Preferred starting biological feedstocks for blend preparation include triglycerides and fatty acids, plant-derived oils (e.g., palm oil, rapeseed oil (canola oil), corn oil, and soybean oil) and animal-derived fats and oils (e.g., tallow, lard, chicken fat (schmaltz) (e.g., chicken fat) and fish oil), and mixtures of these.

[0013] Integration of the process with an oil refinery is an important aspect of the process and allows for a circular economy with disposable waste plastics such as polypropylene. Therefore, the blend is passed into a refinery FCC unit. The blend is passed at a temperature above its pour point so that the blend can be pumped to the refinery FCC unit. The blend is heated to a temperature above the melting point of the plastic before injection into the reactor. Liquid petroleum gas C is recovered from the FCC unit. 3 Olefin / paraffin mixture. 3 Separation of olefin / paraffin mixture into C 3 Alkanes and C 3 Olefin fraction. 3 The olefin is passed into a propylene polymerization reactor to produce polypropylene. 3 The paraffins are sent to a dehydrogenation unit to produce additional propylene, which can be used to produce polypropylene.

[0014] A refinery will typically have its own hydrocarbon feed flowing through the refinery unit. An important aspect of the present method is not to negatively impact the operation of the refinery. The refinery must still produce valuable chemicals and fuels. Otherwise, the combination of the method with an oil refinery will not be a viable solution. The flow volume must therefore be carefully observed.

[0015] The flow volume of the waste plastic / biomass raw material blend entering a refinery device can account for any actual or adapted volume % of the total flow entering a refinery device. Typically, the blend flow can be up to about 100 volume % of the total flow, i.e., the blend flow is the entire flow, without refinery flow. In one embodiment, the blend flow is an amount of up to about 50 volume % of the total flow (i.e., refinery flow and blend flow).

[0016] Among other factors, it has been found that a blend of waste plastics and bio-based materials can be prepared, and if necessary, the blend can be made sufficiently stable for storage or transportation. In addition, the blend can then be converted into value-added chemicals and fuels in a conversion unit. Bio-based materials are used together with waste plastics to significantly enhance the environmental aspects of conversion and regeneration methods. By further having a conversion unit part of a refinery operation, technicians can efficiently and effectively regenerate plastic waste while also supplementing the operation of refining in the preparation of higher value products such as gasoline, jet fuel, base oil and diesel. And, by adding refinery operations, it has been found that clean LPG (propane, propylene, butane and butylene) and naphtha can be efficiently and effectively produced by waste plastics for final polypropylene polymer production. The whole process from recycled plastics to the polymer product with the same product quality as the original polymer has achieved positive economic benefits, while also enhancing the environmental aspects of the regeneration method by using a blend of bio-based materials and waste plastics.

[0017] BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 depicts the current practice (base case) of pyrolyzing waste plastics to produce fuels or waxes.

[0019] Figure 2 The present method of preparing a hot, homogeneous liquid blend of plastic and biofeedstock and feeding the blend into a conversion unit is described.

[0020] Figure 3 The stable blend preparation apparatus process is described in detail, and how the stable blend can be added to the conversion apparatus.

[0021] Figure 4 Describe the classification of plastic types for recycling of waste plastics.

[0022] Figure 5 The process is described wherein the produced blend is passed to a conversion unit in a refinery to produce value added chemicals and fuels, as well as chemicals for the production of recycled polypropylene.

[0023] Figure 6 The present method of establishing a circular economy for waste plastics is described wherein a plastic / bio-oil blend is passed to a refinery FCC feed pre-treater and then to a refinery FCC unit.

[0024] Figure 7Thermogravimetric analysis (TGA) graphically depicting the thermal stability of polyethylene and polypropylene.

[0025] Details

[0026] In the present method, a method for recycling waste plastics such as polyethylene and / or polypropylene back to value-added chemicals and fuels and original polypropylene is provided. Most of the polyethylene and polypropylene polymers are used in disposable plastics and are discarded after their use. Disposable plastic waste has become an increasingly important environmental issue. At present, it seems that there is little option for recycling polyethylene and polypropylene waste plastics into value-added chemicals and fuel products. At present, only a small amount of polyethylene / polypropylene is regenerated by chemical regeneration, wherein recycled and clean polymer pellets are pyrolyzed in a pyrolysis unit to prepare fuels (naphtha, diesel), steam cracker feeds or oily waxes.

[0027] Polypropylene is widely used in a variety of consumer and industrial products. Polypropylene is the second most produced commodity plastic after polyethylene and has mechanical robustness and high chemical resistance. Polypropylene is widely used in packaging, films, fibers for carpets and clothing, molded articles, and extruded tubes. Currently, only a small portion of spent polypropylene products are collected for recycling due to the inefficiency and ineffectiveness of recycling efforts discussed above.

[0028] A method for regenerating plastic waste back into clean monomers is now provided, wherein the waste plastic and bio-feedstock are converted simultaneously in a conversion unit. The clean monomers can be used for value-added chemicals, fuels, as monomers for polymerization, such as regenerated polypropylene. The method includes preparing a novel blend of waste plastic and bio-feedstock. The blend is converted in a conversion unit, such as a catalytic process unit.

[0029] The integrated process produces feedstock to make clean monomers for polymerization. The integrated process produces clean, regenerated propane and propylene. The clean, regenerated propane and propylene streams can be used for polypropylene production. The quality of the final polypropylene product is not reduced due to the recycling of plastic waste.

[0030] At the same time, high-quality gasoline, jet and diesel fuels can be produced from waste plastics in refineries. The fuel components are upgraded by chemical conversion processes in suitable refinery units. The final transportation fuel produced by the integrated process is of high quality and meets fuel quality requirements.

[0031] A simplified process diagram of the basic conditions of the waste plastic pyrolysis process commonly operated in the industry today is shown in Figure 1. Typically, waste plastics are sorted together 1. The cleaned plastic waste 2 is converted into exhaust gas 4 and pyrolysis oil (liquid product) in a pyrolysis unit 3. The exhaust gas 4 from the pyrolysis unit 3 is used as fuel to operate the pyrolysis unit. An on-site distillation unit separates the pyrolysis oil to produce naphtha and diesel 5 products, which are sold to the fuel market. The heavy pyrolysis oil fraction 6 is recycled back to the pyrolysis unit 3 to maximize the fuel yield. Charcoal 7 is removed from the pyrolysis unit 3. The heavy fraction 6 is rich in long-chain linear hydrocarbons and is very waxy (i.e., forms paraffin wax when cooled to ambient temperature). Wax can be separated from the heavy fraction 6 and sold to the wax market.

[0032] The use of the present waste plastic / biofeed blend provides many advantages over pyrolysis methods. The present method does not pyrolyze the waste plastic. Instead, the blend of biofeed and waste plastic is directly converted in the conversion unit.

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

[0034] The preferred range of plastics in the composition blend is about 1-20 weight %. In one embodiment, the conditions for preparing the hot liquid blend include heating the blend to a melting point higher than the plastic while vigorously mixing with the biomass. Process conditions may include heating to 250-550°F, a residence time of 5-240 minutes at the final heating temperature, and 0-10 psig atmospheric pressure. This can be carried out in an open atmosphere and preferably in an oxygen-free atmosphere.

[0035] Alternatively, the blend is prepared in a stable blend preparation unit where the hot homogeneous liquid blend is cooled to ambient temperature in a controlled manner to allow easy storage and transportation. By using this method, a stable blend can be prepared at a remote facility away from a refinery and can be transported to a refinery unit. The stable blend is then heated to above the melting point of the plastic to be added to the refinery conversion unit. The stable blend is a physical mixture of micron-sized plastic particles finely suspended in a petroleum-based oil. The mixture is stable and there is no sedimentation or agglomeration of the plastic particles when stored for an extended period of time.

[0036] This stable blend is made by a two-step process. The first step produces a hot, uniform liquid blend of plastic melt and biomass. The preferred range of the plastic composition in the blend is about 1-20% by weight. In one embodiment, the conditions for preparing the hot liquid blend include heating the plastic to a melting point greater than the plastic while mixing vigorously with the biomass. Preferred process conditions include heating to 250-550°F, a residence time of 5-240 minutes at the final heating temperature, and 0-10 psig atmospheric pressure. This can be carried out in an open atmosphere and preferably in an oxygen-free, inactive atmosphere.

[0037] In a second step, the hot blend is cooled down to below the melting point of the plastic while continuing to mix vigorously with the biofeedstock, and then further cooled to a lower temperature, preferably ambient temperature, to produce a stable blend.

[0038] The resulting composition comprises a stable blend of waste plastic and bio-feedstock for direct conversion of waste plastic in a conversion unit such as a refinery process unit. The resulting composition is novel and provides numerous benefits.

[0039] The stable blend is made from biomass and 1-20 wt% plastic waste, wherein the plastic is mostly polyethylene, polypropylene and / or polystyrene, and the plastic is in the form of finely divided micron-sized particles.

[0040] When a single plastic is used, it is clear that the blend is heated to a temperature greater than the melting point of the plastic. However, if the waste plastic contains more than one waste plastic, the melting point of the plastic with the highest melting point is exceeded. Therefore, the melting points of all plastics must be exceeded. Similarly, if the blend is cooled to below the melting point of the plastic, the temperature must be cooled to below the melting points of all plastics that make up the blend.

[0041] There are several advantages over pyrolysis achieved by implementing these concepts.

[0042] The present method does not pyrolyze waste plastics. Instead, a blend of biomass and waste plastics is prepared. Thus, the pyrolysis step can be avoided, which is a significant energy saving.

[0043] Stable blends of plastic and bio-based materials can be stored at ambient temperature and pressure for extended periods of time. During storage, no polymer agglomeration and no chemical / physical degradation of the blend were observed. This allows for easier processing of waste plastic materials for storage or transportation.

[0044] The stable blend can be easily handled by using standard pumps typically used in refineries or warehouses, or by using a pump equipped with a transport tank. Depending on the blend, some heating of the blend to above its pour point is required to pump the blend for transfer or addition to a conversion unit in a refinery. During heating, no polymer agglomeration was observed.

[0045] For addition to the conversion unit, the stabilized blend is further heated to above the melting point of the plastic to produce a homogenous liquid blend of bio-feedstock and plastic. The hot homogenous liquid blend is directly added to the oil refinery process unit for conversion of waste plastic and bio-feedstock into high-value sustainable products with high yield.

[0046] Also compared to pyrolysis units, these blend preparation units operate at much lower temperatures (~500-600°C versus 120-300°C). Thus, the present process is a much more energy efficient process in preparing refinery feedstocks derived from waste plastics than thermal cracking processes such as pyrolysis.

[0047] The use of this waste plastic / biomass raw material blend further increases the total hydrocarbon yield obtained from waste plastic. This increase in yield is significant. The hydrocarbon yield using this blend provides a hydrocarbon yield of up to 98%. In contrast, pyrolysis produces a large amount of light products (about 10-30% by weight) from plastic waste, and about 5-10% by weight of char. These light hydrocarbons are used as fuel to operate the pyrolysis plant, as mentioned above. Therefore, the liquid hydrocarbon yield from the pyrolysis plant is at most 70-80%.

[0048] In addition, when the present blend is passed into a refinery unit such as an FCC unit, only a small amount of waste gas is generated. The refinery unit uses a catalytic cracking process that is different from the thermal cracking process used in pyrolysis. Using a catalytic process, the production of undesirable light end by-products such as methane and ethane is minimized. The refinery unit has efficient product fractionation and can efficiently utilize all hydrocarbon product streams to produce high value materials. The refinery co-feed will produce only about 2% waste gas (H 2 , methane, ethane, ethylene). 3 and C 4 The stream is captured to produce usable products such as cyclic polymers and / or quality fuel products. Thus, use of the present petroleum / plastic blend provides increased hydrocarbons from plastic waste, as well as a more energy efficient recycling process compared to thermal processes such as pyrolysis.

[0049] The present process converts single-use waste plastics in large quantities by integrating the waste plastics blended with petroleum product streams into oil refinery operations. The resulting process produces feedstocks for polymers (liquefied petroleum gas (LPG), C 3 olefin streams), high-quality gasoline, diesel and jet fuels and / or quality base oils.

[0050] In general, the present method provides a circular economy for polypropylene plants. Polypropylene is produced by the polymerization of pure propylene. Clean propylene can be made from a propane dehydrogenation unit. In addition, propylene can be obtained from an oil refining fluid catalytic cracking (FCC) unit, which produces a mixture of propylene and propane liquefied petroleum gas (LGP). Pure propylene is separated from the mixture using a propane / propylene separator (high efficiency distillation column (PP separator)).

[0051] By adding a refinery operation to upgrade waste plastics to higher value products (gasoline, jet fuel and diesel, base oils) and produce clean propylene for polypropylene polymer production, positive economic benefits are achieved for the entire process of recycling plastics to a polypropylene product with the same product quality as the original polymer. Moreover, by combining the present recycling process with an oil refinery operation, a more energy efficient and effective process is achieved while avoiding any problems of refinery operations.

[0052] Integration of refinery operations becomes very important on the other hand. Waste plastics contain pollutants, such as calcium, magnesium, chlorides, nitrogen, sulfur, dienes and heavy components, which cannot be used in large quantities for blending in transportation fuels. It has been found that by passing these products through refinery units, pollutants can be captured in pre-treatment units and their negative impact is reduced. Fuel components can be further upgraded by using appropriate refinery units of chemical conversion methods, and the final transportation fuel produced in the integrated method is of higher quality and meets fuel quality requirements. The integrated method will produce cleaner and purer propane streams for propane dehydrogenation units and ultimately for polypropylene production. These large, in-spec productions make the "circular economy" of recycled plastics possible.

[0053] The carbon flow in and out of the refinery operations is “transparent,” meaning that all molecules from the waste plastic do not have to end up in the exact olefin product that is recycled back into the polyolefin plant, but are still considered a “credit” because the net “green” carbon flow in and out of the refinery is positive. Through these integrated approaches, the amount of virgin feed required for the polypropylene plant is significantly reduced.

[0054] Figure 2 The method for preparing the heat homogeneous blend of plastics and bio-materials according to the present technology is described. The hot liquid blend can be used for direct injection into a conversion device. The preferred range of the plastic composition in the blend is about 1-20 weight %. If high molecular weight polypropylene (average molecular weight is 250,000 or greater) waste plastics or high density polyethylene (density greater than 0.93g / cc) is used as the main waste plastics, such as at least 50 weight %, the amount of the waste plastics used in the blend is more preferably about 10 weight %. The reason is that the pour point and viscosity of the blend will be high.

[0055] Preferred conditions for blend preparation include heating the plastic to a temperature greater than the melting point of the plastic while vigorously mixing with the biomass. Preferred process conditions include heating to a temperature of 250-550°F, a residence time of 5-240 minutes at the final heating temperature, and an atmospheric pressure of 0-10 psig. This can be done in an open atmosphere and preferably in an oxygen-free, inert atmosphere.

[0056] With reference to the attached drawings Figure 2 , showing a step-by-step preparation method for preparing a blend of plastic and bio-based raw materials. 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 oil 24 in a hot blend preparation device 23. After mixing in 23, a hot, uniform blend 25 of plastic and bio-oil is recovered. Optionally, a filtering device (not shown) can be added to remove any undissolved plastic particles or any solid impurities present in the liquid blend. The blend of plastic and bio-oil can then be passed into a catalytic converter 27. In the present method, in one embodiment, the converter is a refinery unit such as an FCC unit. Optionally, the converter can co-process vacuum gas oil 20 or another refined conventional feedstock.

[0057] Figure 3 A method for preparing a stable blend of plastic and oil for use in the present method is described. The stable blend is prepared in a stable blend preparation apparatus by a two-step process. The first step produces a hot, homogeneous liquid blend of the plastic melt and the biomass feedstock. This step is similar to the Figure 2 The same as described in the hot blend preparation of the invention. The preferred range of the plastic composition in the blend is about 1-20% by weight. If high molecular weight polypropylene (average molecular weight of 250,000 or more) waste plastic or high density polyethylene (density greater than 0.93 g / cc) is used as the main waste plastic, such as at least 50% by weight, the amount of waste plastic used in the blend is more preferably about 10% by weight. The reason is that the pour point and viscosity of the blend will be high.

[0058] Preferred conditions for the preparation of a hot, homogeneous liquid blend include heating the plastic to a temperature greater than the melting point of the plastic while vigorously mixing with the biomass. Preferred process conditions include heating to a temperature of 250-550°F, a residence time of 5-240 minutes at the final heating temperature, and 0-10 psig atmospheric pressure. This can be done in an open atmosphere and preferably in an oxygen-free, inert atmosphere.

[0059] In the second step, the hot blend is cooled down to below the melting point of the plastic while continuing to mix vigorously. An optional diluent may be added during mixing. Further cooling to a lower temperature, preferably ambient temperature, produces a stable blend of plastic and oil.

[0060] It was found that the stable blend is an intimate physical mixture of plastic and bio-raw material. The plastic is in a "deagglomerated" state. At temperatures below the melting point of the plastic, and particularly at ambient temperature, the plastic maintains a fine dispersion of solid particles in the bio-raw material. The blend is stable and allows easy storage and transportation. In a refinery, the stable blend can be heated in a preheater to above the melting point of the plastic to produce a hot, uniform liquid blend of the plastic and the bio-raw material. The hot liquid blend can then be added to the refinery unit alone or as a co-feed with conventional refinery feeds.

[0061] exist Figure 3 , additional details of the preparation of a stable blend are shown. A stable blend is made in a two-step process in a stable blend preparation device 100. As shown, clean waste 22 is passed into a hot blend preparation device 23. The selected plastic waste 22 is mixed with a bio-raw oil 24 and heated to a temperature higher than the melting point of the plastic in the device 23. The mixing is often quite intense. An optional diluent 26 may be added during mixing. The mixing and heating conditions may typically include heating at a temperature in the range of about 250-550°F, with a residence time of 5-240 minutes at the final heating temperature. Heating and mixing may be performed in an open atmosphere or in an oxygen-free inert atmosphere. The result is a hot, uniform liquid blend 101 of plastic and oil. Optionally, a filtering device (not shown) may be added to remove any undissolved plastic particles or any solid impurities present in the hot, uniform liquid blend.

[0062] The hot blend 101 is then cooled to below the melting point of the plastic while mixing of the plastic and bio-oil blend continues in unit 102. An optional diluent 103 may be added during mixing and cooling. Cooling typically continues, often to ambient temperature, to produce a stable blend of plastic and oil 29. At the refinery, the stable blend may be fed to a preheater 130, which heats the blend to above the melting point of the plastic to produce a hot, homogeneous mixture of the plastic / oil blend 105, which is then fed to a refinery conversion unit 27. Optionally, the conversion unit may co-process vacuum gas oil or another conventional refinery feedstock.

[0063] The preferred plastic starting material for the present process is sorted into waste plastics containing mainly polyethylene and polypropylene (plastic recycling classification types 2, 4 and 5). The pre-sorted waste plastics are cleaned and shredded or pelletized to be fed into the blend preparation unit. Figure 4 Describe the plastic type classification for waste plastic recycling. Classification types 2, 4 and 5 are high density polyethylene, low density polyethylene and polypropylene respectively. Any combination of polyethylene and polypropylene waste plastics can be used. For this method, at least some polyethylene waste plastics are preferred. Polystyrene (classification 6) can also exist in limited amounts.

[0064] Proper sorting of waste plastics is very important in order to minimize contaminants such as N, Cl and S. 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%. The present method can tolerate moderate amounts 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%.

[0065] The cleaning of waste plastics can remove non-metallic pollutants and metal pollutants such as sodium, calcium, magnesium, aluminum from other waste sources. Non-metallic pollutants include pollutants such as silicon oxide from Group IV of the periodic table, pollutants such as phosphorus and nitrogen compounds from Group V, pollutants such as sulfur and oxygen compounds from Group VI, and halide pollutants such as fluoride, chloride and iodide from Group VII. It is necessary to remove residual metals, non-metallic pollutants and halides to less than 50ppm, preferably less than 30ppm and most preferably less than 5ppm.

[0066] The term "bio" refers to biochemicals and / or natural chemicals found in nature. Thus, a bio-based material or bio-oil will contain such natural chemicals. Preferred starting bio-based materials for blend preparation include triglycerides and fatty acids, plant-derived oils (e.g., palm oil, rapeseed oil, corn oil, and soybean oil), and animal-derived fats and oils (e.g., tallow, lard, chicken fats (e.g., chicken fat), and fish oils, and mixtures of these. In one embodiment, the bio-based material may include a biomass pyrolysis oil prepared by pyrolyzing a bio-based material.

[0067] The most preferred biomass feedstocks are palm oil and beef tallow, which have a high degree of saturation, exhibiting an iodine value of 91 or less (i.e., a low degree of unsaturation). The iodine value (or iodine number) is a measure of the amount of unsaturation in fats, oils, and waxes. It is determined by measuring the mass of iodine in grams consumed by 100 g of a substance. A higher value means that the substance is less saturated. It is similar to using the bromine number to measure the degree of unsaturation in a petroleum sample.

[0068] It was found that biomaterials with polyunsaturated fatty acids with high iodine values, such as soybean oil (with an iodine value of 130), did not form stable blends with plastics. However, biomaterial mixtures composed of low (≤70) and high (>70) iodine value biomaterials can form stable blends with plastics. It was found that biomaterial mixtures with about 95 iodine values ​​or less formed stable blends with plastics. In one embodiment, the mixture of biomaterials exhibited an iodine value of 91 or less.

[0069] In addition, plastic and biomass blends can be blended with other diluent hydrocarbons such as heptane as needed to change the properties of the blends such as viscosity or pour point, for easier handling or for processing. Preferred blended hydrocarbon feedstocks include standard petroleum-based feedstocks such as vacuum gas oil (VGO), aromatic solvents or light cycle oil (LCO). In one embodiment, the blended hydrocarbon feedstock comprises atmospheric gas oil, VGO or heavy materials recovered from other refinery operations. In another embodiment, the blended hydrocarbon feedstock comprises LCO, heavy cycle oil (HCO), FCC naphtha, gasoline, diesel, toluene or aromatic solvents derived from petroleum. A portion of liquid FCC products (such as naphtha and LCO) can also be recycled to the blend to reduce viscosity. In one embodiment, no petroleum feedstock is used, and only biomass feedstock is used in producing the blend and mixing with the blend.

[0070] Without wishing to be bound by theory, the stable blend prepared is a close physical mixture of plastic and bio-feedstock for catalytic converters. The present method produces a stable blend of bio-feedstock and plastic, wherein the plastic is in a "deagglomerated" state. This blend is stable and allows easy storage and transportation. In a refinery, the stable blend is preheated to a hot, uniform liquid blend of plastic and bio-feedstock above the melting point of the plastic, and the hot liquid blend is then added to the converter. Both the bio-feedstock and the plastic are then converted simultaneously in a converter having a typical refinery catalyst containing zeolites and other active components such as silica-alumina, alumina and clay.

[0071] Catalytic conversion units such as fluid catalytic cracking (FCC) units, hydrocracking units, and hydrotreating units convert a hot, homogeneous, liquid blend of plastic and biomass in the presence of a catalyst for simultaneously converting plastic and biomass. The presence of a catalyst in the conversion unit allows waste plastics to be converted to higher value products at operating temperatures lower than typical pyrolysis temperatures. For hydroprocessing units (hydrocracking and hydrotreating units), hydrogen is added to the unit to improve the conversion of plastics.

[0072] Fluid catalytic cracking process is the preferred mode for catalytic conversion of stable blends.Catalyst selection is optimized to maximize monomer production for virgin plastic manufacturing.

[0073] The yield of undesirable byproducts (exhaust gases, tars, coke) is lower than typical pyrolysis processes. The blends can produce additional synergistic benefits from the interaction of plastic and biofeedstock during the conversion process.

[0074] The blend of plastic and bio-feedstock allows for more efficient regeneration of waste plastics and enables fully circular and sustainable plastic and chemical production. It is far more energy efficient than current pyrolysis processes and allows for regeneration with a lower carbon footprint. The improved process allows for the establishment of a circular economy on a much larger scale by efficiently converting waste plastics back into virgin quality polymers or value-added chemicals and fuels.

[0075] A dedicated conversion unit for the conversion of plastic and bio-feedstock blends will produce sustainable, low-carbon chemical intermediates and fuels without the use of any petroleum feedstocks.

[0076] Preferably, the plastic and biomass blend can be added to an oil refinery conversion unit for co-processing with petroleum-based oils. For the simultaneous conversion of plastics, biomass and petroleum-based oils, refinery conversion units such as fluid catalytic cracking (FCC) units, hydrocracking units and hydrotreating units are preferred.

[0077] In such a case, the refinery will generally have its own hydrocarbon feed flowing through the refinery unit. For example, the hydrocarbon feed may be VGO. The flow of the blend entering a refinery unit such as an FCC unit may account for any actual or adapted volume % of the total flow entering the refinery unit. Typically, for practical reasons, the blend flow may be up to about 50 volume % of the total flow (i.e., refinery flow and blend flow). In one embodiment, the blend flow is an amount accounting for up to about 100 volume % of the total flow. The volume % of the blend will also depend on the desired final product. If aromatics and xylene are focus chemicals, the blend flow % may be much higher, if not 100%. In another embodiment, the blend volume flow is an amount accounting for up to about 25 volume % of the total flow. It has been found that about 50 volume % is a fairly practical amount for the refinery to affect, while also providing excellent results, and is an adaptable amount. It is important to avoid any negative impact on the refinery and its products. If the amount of plastic in the final blend (comprising the plastic / oil blend and the co-feed petroleum) is greater than 20 wt% of the final mixture, the FCC unit operation may experience difficulties. The final blend means the present plastic / oil blend and any co-feed petroleum. The plastic / oil blend may comprise up to 100 vol% of the feed to the refinery unit.

[0078] exist Figure 5 In the cracking of the plastic / bio-oil thermal blend 25, either alone or in combination with a co-feed petroleum feed, the plastic / bio-oil thermal blend 25 may be passed to a conversion FCC unit 27 via 26. Figure 2 and 3 The same Figure 5 The numbers in the table refer to the same stream or unit. FCC unit 27 produces C 3 of liquefied petroleum gas (LPG) and C 4Olefin / paraffin streams 31 and 32 as well as naphtha 33 and heavy fraction 30. C of propane and propylene mixture 31 3 The olefin / paraffin mixed stream may be fed to and separated by a propane / propylene splitter (PP splitter) 50 to produce pure steam of propane 51 and propylene 52. The propylene 52 is fed to a propylene polymerization unit 52 to produce polypropylene.

[0079] Pure propane 51 can be fed to a propane dehydrogenation unit 54 to produce additional propylene 55 and then in a propylene polymerization unit 53 to ultimately produce polypropylene.

[0080] The dehydrogenation of propane is widely practiced in industry to produce propylene. The reaction is endothermic and the conversion is maintained by a multistage reactor and interstage heaters. The device typically operates at high temperature (>900°F) and low pressure (<50 psig) in the presence of a noble metal (Pt) catalyst. The multistage process produces a propylene / propane mixture of about 85% purity. The stream is directed to a propane / propylene (PP) separator, which is an efficient distillation column. The separator produces a pure propylene stream with a purity of 99.5-99.8%.

[0081] The PP separator unit and / or the propane dehydrogenation unit can be located away from the refinery, near the refinery, or within the refinery. The propane / propylene mixture is delivered to the PP separator by truck, barge, rail car, or pipeline. It is preferred that the PP separator unit and the propane dehydrogenation unit are in close proximity to the refinery FCC unit.

[0082] C 4 32 and other hydrocarbon product streams, such as heavy fractions 30 from FCC unit 27, are sent to suitable refinery units 34 for upgrading to clean gasoline, diesel or jet fuel. Gasoline 33 from the FCC unit can be directly passed to the gasoline pool 35, or further upgraded (not shown) before being sent to the gasoline pool.

[0083] The polypropylene polymer 56 produced in the propylene polymerization unit 53 may be made into a polypropylene product 57 which may then be further incorporated into consumer products.

[0084] Figure 6 Show for example Figure 5 The integrated process shown in FIG. 1 is a process in which a co-feed of the blend and the hydrocarbon refinery stream 26 is first sent to a fluid catalytic cracking (FCC) feed pre-treater unit 77. Figure 5 The same Figure 6 The numbers in refer to the same stream or refinery unit.

[0085] FCC feed pre-treaters typically use a bimetallic (NiMo or CoMo) alumina catalyst in a fixed bed reactor at 660-780°F reactor temperature and 1000-2000 psi pressure with H 2 The gas stream hydrogenates the feed. The refinery FCC feed pre-treater unit effectively removes sulfur, nitrogen, phosphorus, silica, dienes and metals (which will damage the FCC unit catalyst performance). In addition, the unit hydrogenates aromatic compounds and improves the liquid yield of the FCC unit.

[0086] The pretreated hydrocarbons from the feed pre-treater unit 77 can be distilled to produce LPG, naphtha and heavy fractions. The heavy fraction is sent to the FCC unit 27 to further produce C 3 31. C 4 32, FCC gasoline 33 and heavy fraction 30. C from feed pre-treater 4 The feed stream and naphtha can be fed to other upgrading processes in the refinery to produce gasoline, diesel and jet fuel. 3 The 31 stream is sent to a propane / propylene separator 50. The propylene 52 may be sent directly to the propylene polymerization 53, however the propane 51 may be added to a propane dehydrogenation unit 54 to produce additional propylene for polymerization.

[0087] Polypropylene is produced from the monomer propylene by chain growth polymerization. Ziegler-Natta catalysts or metallocene catalysts are used to catalyze the polymerization of propylene to a polypropylene polymer having the desired properties. These catalysts are activated with a special cocatalyst containing an organoaluminum compound. Industrial polymerization processes use either gas phase polymerization in a fluidized bed reactor or bulk polymerization in a loop reactor. Gas phase polymerization is typically carried out in the presence of H 2 The bulk polymerization is carried out at 60 to 80°C and a pressure of 30-40 atm is applied to keep propylene in a liquid state.

[0088] The propylene polymerization unit 53 is preferably located near a refinery so that the feedstock (propylene) can be transported via a pipeline. For petrochemical plants far from refineries, the feedstock can be transported by truck, barge, rail car or pipeline.

[0089] The benefits of a circular economy and effective and efficient regeneration activities are achieved through this integrated approach.

[0090] The following examples are provided to further illustrate the present method and its benefits. The examples are intended to be illustrative and not limiting.

[0091] Example 1: Properties of plastic samples and bio-raw materials used for blend preparation Five plastic samples were purchased and their properties are summarized in Table 1: low-density polyethylene (LDPE, plastic A), high-density polyethylene (HDPE, plastic B), two polypropylene samples with average molecular weights of ~12,000 (PP, plastic C) and ~250,000 (PP, plastic D), and polystyrene (PS, plastic E).

[0092] Table 1 Properties of the plastics used

[0093]

[0094] The bio-feedstocks used to prepare blends with the plastic melt included palm oil, beef tallow and soybean oil, and their properties are shown in Table 2.

[0095] Table 2 Properties of biomaterials used for blend preparation

[0096]

[0097]

[0098] Thermogravimetric analysis (TGA) was performed using Plastic A (LDPE) and Plastic C (Polypropylene) to verify that the plastic materials were thermally stable well above the melt preparation temperature. Figure 7 The TGA results shown in indicate that the LPDE sample is stable up to 800°F and the polypropylene sample is stable up to 700°F.

[0099] Example 2 - Preparation of stable blends of palm oil and plastic

[0100] Several blends of palm oil and plastic were prepared by adding plastic pellets (Plastics A to D) to palm oil (BioFeed No. 1).

[0101] Use the following procedure.At ambient temperature, palm oil (waxy solid) is added to a beaker.Palm oil is heated with a heating jacket and stirred with a magnetic stirrer.Palm oil temperature is gradually increased to 270-400 ° F, and then pre-weighed plastic pellets (solid) are slowly added to the hot palm oil, stirring and heating simultaneously.After the plastic pellets dissolve, the stirred solution is then maintained at the final temperature for a blend with LDPE and plastic C polypropylene for another 30 minutes, or for a blend with HDPE and plastic D polypropylene for 60 minutes.Then the blend is cooled down to ambient temperature, stirring simultaneously.Visual observation points out that the blend is completely uniform.When cooled to ambient temperature, the blend of plastic and palm oil shows the visual appearance of the waxy solid of palm oil, but the hardening temperature (or solidification temperature) is different from the starting palm oil.

[0102] To evaluate material handling needs, the pour point (per ASTM D5950-14) and viscosity (per ASTM D445) of the blends were measured. In addition, the content of hot heptane insoluble material was measured according to the ASTM D3279 procedure. The hot heptane insoluble method determines the weight percent of material in oil that is insoluble in hot heptane at 80°C. This method uses a 0.8 micron membrane filter to separate insoluble material. The heptane insoluble content provides information about the insoluble plastic in the blend.

[0103] The material stability was observed by visual inspection. The blend of plastic and palm oil was stable and no changes were observed over the 3 month observation period.

[0104] Table 3 below summarizes the list of samples prepared and their properties.

[0105] Table 3 Preparation of stable blends of plastics and palm oil

[0106]

[0107] Pour point and viscosity values ​​are used to guide equipment selection and operating procedures. Compared with the pure bio-based case, the blends made by the addition of plastics show a moderate increase in pour point and viscosity. These changes can be handled with typical refinery operating equipment with little or no modification. The blend tank is heated to above the pour point to change the physical state of the blend to a liquid that can be easily transferred. The liquid blend can then be transferred to a transport vessel or to a refinery device via pumping using a pump or via gravity discharge or via transfer using a pressure difference.

[0108] The stable blend remains as a physical mixture at temperatures up to 80°C. The hot heptane insoluble test is used to separate the plastic from the blend. At 80°C, all the waxes in the palm oil are dissolved in the heptane solvent (Example 2-1) and the heptane insoluble solids are only 0.02 wt%. The weight percentage of the heptane insoluble material comes from the insoluble plastic filtered out with a 0.8 micron membrane filter. The amount recovered as solid material in Examples 2-2 and 2-4 shows 7.6 and 7.8 wt% heptane insoluble solids, similar to the amount of plastic added for blend preparation. The amount recovered is 2.2-2.4 wt%, indicating that very fine particles can be present in the blend with a submicron size. The heptane insoluble results in Table 3 clearly indicate that the plastic at 80°C is a physical mixture of solid particles in the blend dispersed in palm oil, and most of the plastic particles can be separated with a 0.8 micron filter.

[0109] Example 3 - Preparation of Stable Blends of Beef Tallow and Plastic

[0110] Several blends of tallow and plastic samples were prepared by adding plastic pellets to a tallow feed (BioFeed No. 2).

[0111] The procedure described in Example 2 was used for these blend preparations.

[0112] Table 4 Preparation of stable blends of plastic and tallow

[0113]

[0114] The blends made from plastic additions to tallow showed moderate increases in pour point and viscosity compared to the pure bio-based case, similar to the palm oil results shown in Example 2.

[0115] The weight percentage of heptane insoluble material recovered as solid material matches well with the amount of plastic added to the blend preparation. The base tallow (Example 3-1) has only 0.04 wt% heptane insolubles while the stabilized blends (Examples 3-2 and 3-4) show 7.7 and 8.6 wt% heptane insoluble solids content, similar to the amount of plastic added for blend preparation. The amount recovered is 1.4-2.3 wt% less, indicating that very fine particles can be present in the blend that are submicron in size. The heptane insoluble results in Table 4 clearly indicate that the plastic at 80°C is a physical mixture of solid particles dispersed in palm oil in the blend, and most of the plastic particles can be separated out with a 0.8 micron filter.

[0116] Example 4 - Preparation of soybean oil and plastic blends (Comparative Example)

[0117] An attempt was made to prepare blends of soybean oil (biofeed No. 3) and plastic using the procedure described in Example 2 with plastic pellets (Plastics A to D). Surprisingly, the soybean oil and plastic did not make a hot, homogeneous, liquid melt when heated together in the same manner as palm oil or tallow. The pellets did soften and lose their shape when the mixture was heated above the melting point of the plastic. But instead of forming a homogeneous liquid as in other cases, the plastic melt formed a liquid phase that was separate from the soybean oil (SBO). Upon cooling, the plastic phase agglomerated and formed large plastic solids. A possible explanation for this is that SBO has a much higher degree of unsaturation, which is evident from its lower H / C ratio than that of tallow or palm oil and also from the measured iodine value. This also explains why most petroleum feeds, as well as highly saturated oils and fats as determined by iodine value, readily dissolve plastics.

[0118] Table 5 Preparation of stable blends of plastics and soybean oil

[0119]

[0120] Example 5 - Preparation of soybean oil, palm oil and plastic blends

[0121] A 1:1 weight mixture of soybean oil and palm oil (mixed bio-feed) was prepared. Using mixed bio-feed, a successful blend of palm oil, soybean oil and plastic was prepared by adding plastic pellets (Plastics A and C) to a 1:1 mixture of palm oil and soybean oil (Bio-feed No. 1 and Bio-feed No. 3). Therefore, SBO can be used as a component in mixed bio-feed. Stable blends show good shelf life and do not show any changes for several months. These results show that soybean oil can also be used as a bio-feed to prepare a stable blend with plastic by reducing its unsaturation with another bio-feed.

[0122] This test also confirmed acceptable iodine values ​​for making successful stable blends of plastics and bio-feedstocks. The iodine value of a 1:1 mixture of soybean oil and palm oil was estimated to be 91. These results show that soybean oil or other highly unsaturated oils can also be used as bio-feedstocks to make stable blends with plastics, as long as the total unsaturation of the mixed bio-feedstock has an iodine value of 95 or less, and preferably 91 or less.

[0123] Table 6 Preparation of stable blends of plastics, soybean oil and palm oil

[0124]

[0125] Example 6 - Preparation of soybean oil, beef tallow and plastic blends

[0126] Preparation of a 1:1 mixture of soybean oil and beef tallow. Using mixed biofeedstocks, blends of beef tallow, soybean oil, and plastic were successfully prepared by adding plastic pellets (Plastics A and C) to a 1:1 mixture of beef tallow and soybean oil (BioFeed #1 and BioFeed #3). The stable blends showed good shelf life and no changes were seen for several months. These results again show that soybean oil can also be used as a biofeedstock to prepare stable blends with plastics by reducing its unsaturation with another biofeedstock.

[0127] This test also shows acceptable iodine values ​​for making successful stable blends of plastics and bio-feedstocks. The iodine value of a 1:1 mixture of soybean oil and beef tallow was estimated to be 88.

[0128] Table 7 Preparation of stable blends of plastic, soybean oil and beef tallow

[0129]

[0130] To study the impact of processing waste plastics and bio-feedstocks in an FCC unit, laboratory tests of a fluid catalytic cracking (FCC) process were conducted using a stable blend of plastics and bio-feedstocks. Two FCC catalysts were used for the study: a ZSM-5 FCC catalyst made from ZSM-5 zeolite (a 10-membered ring mesoporous zeolite) and a USY FCC catalyst made from USY (a 12-membered ring mesoporous zeolite). Three bio-feedstocks were used: palm oil, soybean oil, and beef tallow.

[0131] Catalytic cracking experiments were carried out in the ACE (Advanced Cracking Evaluation) Model C unit manufactured by Kayser Technology Inc. (Texas, USA). The reactor used in the ACE unit is a fixed fluidized reactor with 1.6 cm ID. Nitrogen is used as fluidizing gas and is introduced from the bottom and top. The top fluidizing gas is used to carry the feed injected via a three-way valve from a calibrated syringe feed pump. Experiments were carried out at atmospheric pressure and a temperature of 975 ° F. For each experiment, a constant amount of 1.5 grams of feed was injected at a rate of 1.2 grams / min for 75 seconds. The catalyst / oil (cat / oi l) ratio was maintained at 6. After 75 seconds of feed injection, the catalyst was stripped by nitrogen for a period of 525 seconds. Liquid products were collected in a sample bottle connected to a glass receiver during the catalytic cracking and stripping process, which was located at the reactor outlet and maintained at -15 ° C. Gaseous products were collected at 1 atm in a closed stainless steel vessel (12.6 L) pre-filled with N2. The gaseous products were mixed by an electric stirrer rotating at 60 rpm as soon as the feed injection was completed. After stripping, the gaseous products were further mixed for 10 minutes to ensure homogeneity. The final gas products were analyzed using a refined gas analyzer (RGA). After the stripping process was completed, in-situ catalyst regeneration was carried out at 1300°F in the presence of air. The regenerated flue gas was passed through a catalytic converter filled with CuO pellets (LECO Inc.) to oxidize CO to CO 2 The flue gas is then analyzed by an online IR analyzer located downstream of the catalytic converter. From the CO measured by the IR analyzer 2 The concentration accounts for the coke deposited during the cracking process.

[0132] The gaseous products (mainly C 1 -C 7 Hydrocarbons) are dissolved in the RGA. The RGA is a custom Agilent 7890B GC equipped with three detectors: a flame ionization detector (FID) for hydrocarbons and two thermal conductivity detectors for nitrogen and hydrogen. A methanizer is also installed on the RGA to quantify trace amounts of CO and CO in the gas products when cracking biomass feedstocks such as soybean oil, palm oil or beef tallow. 2 The gas products are grouped into dry gas (C2 -hydrocarbons and hydrogen), LPG (C 3 and C 4 Hydrocarbons). Remove CO and CO from the dry gas 2 Their yields are reported separately. The liquid products were weighed and analyzed in a simulated distillation GC (Agilent 6890) using the ASTM D2887 method. The liquid products were split into gasoline (C 5 -430°F), LCO (430-650°F) and HCO (650°F+). Gasoline (C 5 + hydrocarbons) are combined with the gasoline in the liquid product as the total gasoline. The light fraction (C 5- ) and add it back to C using some empirical distribution 3 and C 4 For most experiments the material balance was between 98% and 101%.

[0133] A detailed hydrocarbon analysis (DHA) was also performed on the gasoline portion of the liquid product for PONA and octane (RON and MON) using an Agilen 6890A and Hydrocarbon Explorer software from Separation Systems Inc., FL. DHA analysis was not performed on the gasoline portion of the gaseous product. However, the DHA results still provide valuable information to evaluate the properties of the catalytic cracking products.

[0134] Example 7 - Direct conversion of plastics and palm oil via FCC using ZSM-5 catalyst

[0135] Laboratory tests of a fluid catalytic cracking (FCC) process were conducted using a stable blend of plastic and bio-feedstock (Examples 2-2 and 5-1) using an FCC catalyst made of ZSM-5 zeolite and the results are summarized in Table 8.

[0136] Table 8 Evaluation of plastics and palm oil co-fed to FCC using ZSM-5 catalyst

[0137]

[0138]

[0139] The results in Table 8 show that the blend of waste plastics and biomass (palm oil and soybean oil) is well converted using the FCC catalyst containing ZSM-5. Surprisingly, under typical FCC process conditions, the mesoporous 10 yuan ZSM-5 catalyst can convert more than 95% by weight of plastic / biomass blends (Examples 7-1 to 7-3). High conversion leads to very low yields of LCO and HCO. All these situations produce very high LPG and aromatics yields, which shows that the method can be used to produce raw materials for polymer and chemical manufacturing without using petroleum resources.

[0140] Adding 10 wt % plastic to palm oil only causes a small change in the performance of the FCC unit in terms of conversion and the yield of dry gas and coke, indicating that the co-processing of waste plastic and bio-based materials is easily feasible (Example 7-1 relative to Example 7-2). Although 10 wt % low density polyethylene (plastic A) blended to palm oil results in only a small increase in coke and dry gas yields, a significant positive increase in LPG yield (35 relative to 37 wt %) and total aromatic yield (76 relative to 81 wt % in the gasoline fraction) is observed. The significant increase in LPG and aromatic yields from blends containing plastics is quite unexpected. This clearly points out the synergistic effect of bio-based materials and plastic blends in providing an increased yield of LPG and aromatics.

[0141] 10 wt% plastic blended into palm oil and soybean oil (Example 7-3) also showed consistent results of high LPG and aromatics production.

[0142] These results indicate that ZSM-5 catalysts made from medium pore (pour) size zeolites are preferred catalysts for LPG olefins and aromatics production when converting biofeed / plastic blends.

[0143] High yields of LPG using this process are evident. LPG and LPG olefins are desirable feedstocks for polyethylene and polypropylene production.

[0144] The high yield of aromatic compounds using this process is also quite significant, since these aromatic compounds can be used in polystyrene or polyethylene terephthalate production. Another surprising discovery is the selectivity of para-xylene relative to total xylenes. Using the ZSM-5 catalyst, the xylenes produced by this process are essentially para-xylene with a selectivity of about 61-70% para-xylene (relative to the total xylene production). Para-xylene is the most desired xylene isomer for polyethylene terephthalate polymer manufacturing.

[0145] Although this process is more suitable for chemical manufacturing, a portion of the product can be used to prepare high-quality gasoline fuel. The gasoline produced by this process has an excellent octane number of more than 100 due to the high aromatic content in the gasoline fraction. The LCO and HCO yields are low due to the high conversion rate.

[0146] Example 8 - Direct conversion of plastics and palm oil via FCC using USY catalyst

[0147] Laboratory tests of a fluid catalytic cracking (FCC) process were conducted using a stable blend of plastic and palm oil (Examples 2-2 and 5-1) using an FCC catalyst made of USY zeolite and the results are summarized in Table 9.

[0148] Table 9 Evaluation of plastics and palm co-feed to FCC using USY catalyst

[0149]

[0150]

[0151] The results in Table 9 show that the blend of waste plastics and bio-feedstock (palm oil and soybean oil) is well converted using an FCC catalyst containing USY. The overall conversion of the blend is 86-87% (Examples 8-1 to 8-3) under typical FCC process conditions. All of these cases produce low dry gas yields (undesirable products) and high LPG, gasoline and LCO yields (desirable products), which shows that this method can be used to simultaneously produce feedstock chemical manufacturing and high-quality renewable fuels without using petroleum resources.

[0152] Adding 10 wt% plastic to palm oil caused only a small change in the performance of the FCC unit in terms of conversion and yield of dry gas and coke, indicating that co-processing of waste plastic and bio-feedstock is readily feasible (Example 8-1 vs. 8-2). Blending 10 wt% low-density polyethylene (Plastic A) to palm oil had only a small effect on the product yields: LPG yield (19.5 vs. 21.3 wt%), gasoline yield (45.4 vs. 44.9 wt%), LCO (10.9 vs. 10.0 wt%), and HCO yield (3.2 vs. 3.3 wt%). However, due to the paraffinic nature of the plastic, a 3-digit reduction in gasoline octane was observed (91 to 88).

[0153] 10 wt% plastic blended into palm oil and soybean oil (Example 8-3) also showed consistent results of high LPG and gasoline production.

[0154] Using the USY catalyst, no synergistic effect of biomass and plastics was observed, nor was the para-xylene selectivity observed using the ZSM-5 catalyst in Example 7-2 shown. Compared with the ZSM-5 catalyst (Example 8.2 compared to Example 7.2), the USY catalyst produced much higher LCO (10.0 relative to 1.4 wt%) and HCO (3.3 relative to 0.7 wt%) yields. In addition, USY showed much higher coke selectivity (6.7 relative to 1.7 wt%) and lower waste gas yield (2.2 relative to 6.5 wt%). These results indicate that the USY catalyst made of large pore size zeolite is a preferred FCC catalyst for the simultaneous production of chemical feedstocks and high-quality fuels.

[0155] A portion of the product can be used to make premium fuels. Gasoline produced by this process has an octane rating of 91 to 88. Addition of polyethylene plastic causes some reduction in octane due to the paraffinic nature of the plastic. Due to refinery blending flexibility, this octane loss can be compensated by minor blending adjustments.

[0156] High yields of LPG using this process are evident. LPG and LPG olefins are desirable feedstocks for polyethylene and polypropylene production.

[0157] High yields of aromatic compounds using this process are also evident, as these aromatic compounds can be used in polystyrene or polyethylene terephthalate production.

[0158] Example 9 - Direct Conversion of Plastics and Tallow via FCC Using ZSM-5 Catalyst

[0159] Laboratory tests of a fluid catalytic cracking (FCC) process were conducted using a stable blend of plastic and biofeedstock (Examples 3-2, 3-4, and 6-1) using an FCC catalyst made from ZSM-5 zeolite and the results are summarized in Table 10.

[0160] Table 10 Evaluation of plastics and tallow co-fed to FCC using ZSM-5 catalyst

[0161]

[0162] The results in Table 10 show that blends of waste plastics and biomass (tallow and soybean oil) are converted well using FCC catalysts containing ZSM-5. Similar to co-processing with palm oil, the ZSM-5 catalyst shows very high conversions of over 95% by weight of plastic / biomass blends under typical FCC process conditions (Examples 9-1 to 9-4). High conversions result in very low yields of LCO and HCO. All of these cases produce very high yields of LPG and aromatics, which indicates that this method can be used to produce feedstocks for polymer and chemical manufacturing without using petroleum resources.

[0163] Adding 10 wt% polyethylene or polypropylene plastic to tallow caused only a small change in the performance of the FCC unit in terms of conversion and yield of dry gas and coke, indicating that co-processing of waste plastics and bio-feedstocks is readily feasible (Example 9-1 vs. 9-2 and 9-3). Unlike the palm oil case shown in Example 7-2, blending 10 wt% low density polyethylene (Plastic A) and polypropylene (Plastic C) to tallow did not show any synergistic effect on LPG and aromatic yields. The LPG yield (36.5 vs. 35.5-36.4 wt%) and total aromatic yield (80.6 vs. 80.3-80.6 wt% in gasoline fraction) were similar to the plastic co-feed case.

[0164] 10 wt% plastic blended into tallow and soybean oil (Example 9-4) also showed consistent results of high LPG and aromatics production as well as high para-xylene selectivity.

[0165] The high yields of LPG and aromatics shown in Table 10 again indicate that the ZSM-5 catalyst made of medium pore size zeolite is a preferred catalyst for producing LPG olefins and aromatics from a blend of plastics and bio-feedstocks such as tallow. Using the ZSM-5 catalyst, the xylenes produced by this process are essentially para-xylene with a para-xylene selectivity of about 65-67% (relative to the total xylene production).

[0166] Example 10 - Direct conversion of plastics and tallow via FCC using USY catalyst

[0167] Laboratory testing of a fluid catalytic cracking (FCC) process using a stable blend of plastic and tallow biofeedstock (Examples 3-2, 3-4, 6-1) was performed using an FCC catalyst made of USY zeolite and the results are summarized in Table 11.

[0168] Table 11 Evaluation of plastics and tallow co-fed to FCC using USY catalyst

[0169]

[0170]

[0171] The results in Table 11 show that the blend of waste plastic and bio-feedstock (tallow and soybean oil) was well converted using the FCC catalyst containing USY. The overall conversion of the blend was 85-87% (Examples 10-1 to 10-4) under typical FCC process conditions. All of these cases produced low dry gas yields (undesirable products) and high LPG, gasoline and LCO yields (desirable products), indicating that this method can be used to simultaneously produce feedstocks for chemical manufacturing and high-quality fuels without using petroleum resources.

[0172] Addition of 10 wt% plastic to tallow caused only minor changes in FCC unit performance in terms of conversion and yield of dry gas and coke, indicating that co-processing of waste plastic and bio-feedstock is readily feasible (Example 10-1 vs. 10-2 and 10-3). Blending of 10 wt% low density polyethylene (Plastic A) or polypropylene (Plastic C) to tallow slightly increased LPG yield (20.1 vs. 21.6-22.6 wt%) with only minor effects on other product yields: gasoline yield (44.6 vs. 43.6-44.3 wt%), LCO (10.5 vs. 10.2-11.0 wt%) and HCO yield (3.5 vs. 3.2-3.3 wt%). No drop in gasoline octane was observed in the case of co-feed of polyethylene, and gasoline octane increased by 2 numbers in the case of co-feed of polypropylene (88.0 vs. 87.9 vs. 92.3).

[0173] These results indicate that USY catalysts made from large pore size zeolites are preferred catalysts for the simultaneous production of chemical feedstocks and high-quality renewable fuels.

[0174] As used in this disclosure, the words "comprising" or "comprising" are intended to be open ended transitional, meaning the specified elements are included but not necessarily excluding other unspecified elements. The phrases "consisting essentially of" or "consisting essentially of" are intended to mean excluding other elements of any significance to the composition. The phrases "consisting of" or "consisting of" are intended to be transitional, meaning excluding all but the recited elements except for only minor trace impurities.

[0175] All patents and disclosures cited herein are incorporated herein by reference to the extent that they are not inconsistent with this article. It will be understood that some of the above-mentioned structures, functions and operations of the above-mentioned embodiments are not necessary for implementing the present invention, and are included in the description only for the completeness of one or more exemplary embodiments. In addition, it will be understood that the specific structures, functions and operations set forth in the above-mentioned patents and disclosures can be implemented in conjunction with the present invention, but they are not necessary for the implementation of the present invention. It should therefore be understood that the present invention can be implemented in a manner different from the specific description without actually departing from the spirit and scope of the present invention as defined by the appended claims.

Claims

1. A method for converting waste plastics into regenerants for polypropylene polymerization, comprising: (a) selecting waste plastics comprising polyethylene and / or polypropylene; (b) preparing a blend of a bio-feedstock and a selected waste plastic, wherein the blend comprises about 20% by weight or less of the selected waste plastic; (c) passing the blend into an FCC unit at a temperature above the melting point of the plastic; (d) recovering a C3 olefin / paraffin mixture from the FCC unit; (e) separating C3 paraffins and C3 olefins into different fractions; and (f) introducing C3 olefin into a propylene polymerization reactor.

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

3. The process of claim 1, wherein the blend of (b) is a hot, intimate blend of waste plastic and bio-oil.

4. The method of claim 1, wherein the blend of (b) is a stabilized blend of waste plastic and bio-oil.

5. The process of claim 1, wherein a polypropylene product is prepared from the polymerized propylene.

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

7. The method according to claim 2, wherein the gasoline recovered from the FCC unit is sent to a gasoline blending tank.

8. The process of claim 1, wherein the C4 stream and heavy fractions are recovered from the FCC unit distillation column and further processed into clean gasoline, diesel or jet fuel in a refinery.

9. The process of claim 1, wherein the volume flow rate of the blend entering the FCC unit in (c) accounts for at most 100 volume % of the total hydrocarbon flow entering the FCC unit.

10. The process of claim 1, wherein the volume flow rate of the blend entering the FCC unit in (c) is at most 50 volume % of the total hydrocarbon flow rate entering the FCC unit.

11. The process of claim 10, wherein the blend flow rate is at most 25 volume % of the total flow entering the FCC unit.

12. The method of claim 1, wherein the blend of bioraw material and selected waste plastic in (b) is prepared by heating the waste plastic and bioraw material mixture to a temperature above the melting point of the plastics and then cooling the blend to a temperature below the melting point of the waste plastic.

13. The method of claim 1, wherein the biological feedstock comprises triglycerides and / or fatty acids.

14. The method of claim 1, wherein the biological feedstock comprises plant-derived oils and / or animal-derived fats and oils.

15. The method of claim 14, wherein the plant-derived oil comprises palm oil, rapeseed oil, corn oil, soybean oil, or a mixture thereof.

16. The method of claim 14, wherein the biological feedstock comprises beef tallow, lard, chicken fat, fish oil, or mixtures thereof.

17. The method of claim 1, wherein the biological feedstock comprises palm oil, beef tallow, soybean oil, or a mixture thereof.

18. The method of claim 1, wherein the biological feedstock comprises biomass pyrolysis oil.

19. The method of claim 1, wherein the biological raw material comprises a biological raw material or a mixture of biological raw materials having an iodine value of 95 or less.

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

21. The method of claim 19, wherein the biological raw material comprises a mixture of a biological oil or fat exhibiting an iodine value of 70 or less and a biological oil or fat exhibiting an iodine value of greater than 70.

22. The method of claim 1, wherein a petroleum feedstock stream comprising LCO or gasoline is added to reduce the blend viscosity.

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

24. The method of claim 23, wherein the petroleum feedstock comprises 1-50 volume percent of the mixed blend.

25. The method of claim 24, wherein the petroleum-based feedstock comprises atmospheric gas oil, vacuum gas oil (VGO), atmospheric residue, petroleum-derived oils, petroleum-based materials, and / or heavy materials recovered from refinery operations.

26. The method of claim 24, wherein the petroleum-based feedstock comprises light cycle oil (LCO), heavy cycle oil (HCO), FCC naphtha, gasoline, diesel, toluene, and / or aromatic solvents derived from petroleum.

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

28. A polypropylene product prepared by the process according to claim 5.

29. Polypropylene prepared by the process according to claim 1.

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