Removal of silicon and other impurities from pyrolysis oil using silica gel matrix

Abstract

A process for reducing siloxanes in a waste plastic pyrolysis oil composition is disclosed. The process can include contacting the waste plastic pyrolysis oil composition with a modified silica gel composition under conditions sufficient to produce a refined waste plastic pyrolysis oil composition. The refined waste plastic pyrolysis oil composition can have at least 50% less siloxanes by weight, preferably at least 60% less siloxanes by weight, compared to the untreated waste plastic pyrolysis oil composition. The siloxanes can include acyclic siloxanes, cyclic siloxanes, or a combination thereof. The modified silica gel composition can include a cobalt or iron composition.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of priority from European Patent Application No. 22201371.6, filed October 13, 2022, the contents of which are incorporated herein by reference in their entirety. [Technical Field]

[0002] The present invention relates generally to systems and methods for processing pyrolysis oil (pyrolysis oil). Specifically, the present invention relates to systems and methods for pretreating waste plastic pyrolysis oil with silica gel to reduce the siloxane content in the pyrolysis oil, which can aid in producing a more stable pyrolysis oil product and / or a more desirable pyrolysis oil feedstock for cracking. [Background technology]

[0003] Plastics are found in industrial and domestic applications. Many tons of plastic are produced every day, but waste plastics create serious environmental problems because they take a very long time to decompose naturally. Therefore, in recent decades, various processes for the reuse and / or recycling of plastics have been investigated.

[0004] Pyrolysis of waste mixed plastics is a process that involves breaking down plastics at high temperatures to produce pie oil, which can be used directly as liquid fuel or further processed to produce high-value chemicals. However, pie oil produced from mixed plastics generally contains high amounts of highly reactive chemicals, which leads to rapid degradation of the pie oil and the formation of gums during transportation and further processing. Therefore, it is quite common for containers and / or chemical processing units in which pie oil is handled and / or processed in the presence of trace amounts of oxygen to become contaminated with pie oil.

[0005] Methods for reducing contaminants in the processing of mixed waste plastics have been described. For example, U.S. Patent Application Publication No. 2009 / 0129994 to Giri et al. describes an absorption system that captures and / or adsorbs gums and / or gum precursors and other heteroatom-containing components. The absorption system can include activated carbon, molecular sieves, bleaching clay, silica hydrogel, ionic resins, hardened eggshell powder, or a combination thereof.

[0006] Overall, while systems and methods exist for treating waste plastic pie oil derived from mixed plastics, there remains a need for improvement in the art. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] International Publication No. 2021 / 255591 Summary of the Invention

[0008] A discovery has been made that provides a solution to at least one of the above-mentioned problems associated with systems and methods for purifying waste plastic pyrolysis oil. In one aspect, the present invention can include a process for reducing siloxanes (e.g., acyclic siloxanes, cyclic siloxanes, or a combination thereof) in a waste plastic pyrolysis oil composition. The process can include treating the waste plastic pyrolysis oil composition with a modified silica gel composition, thereby reducing the amount of siloxanes in the treated composition compared to the untreated composition. In certain aspects, the treated composition can contain at least 50% or at least 60% less siloxanes by weight compared to the untreated composition. The process of the present invention can also reduce or remove other components from the pyrolysis oil composition, such as heteroatom-containing components (e.g., oxygen-containing, organic nitrogen-containing, and chlorine-containing components in waste plastic pyrolysis oil). Siloxanes and / or other components present in waste plastic pyrolysis oil can shorten catalyst life, reduce corrosion, limit NOx production, and reduce pollution when treating the waste plastic pyrolysis oil. Thus, the present invention provides a simple and cost-effective process for reducing siloxanes and other components from waste plastic pyrolysis oil, which allows for more efficient storage, transportation, and / or processing of the treated waste plastic pyrolysis oil of the present invention, and also reduces adverse effects on equipment, components, and catalyst compositions used in storing, transporting, and / or processing the pyrolysis oil.

[0009] In one embodiment of the present invention, a process for reducing siloxanes in waste plastic pyrolysis oil is described. The process can include contacting an unrefined or untreated waste plastic pyrolysis oil composition with a modified silica gel composition under conditions sufficient to produce a refined or treated waste plastic pyrolysis oil composition having at least 50% or at least 60% less siloxanes by weight compared to the unrefined or untreated waste plastic pyrolysis oil composition. The siloxanes can include acyclic siloxanes, cyclic siloxanes, or a combination thereof. The modified silica gel composition can include cobalt (e.g., CoCl) and / or iron. The modified silica gel composition can include silica gel particles, granules, powder, or a combination thereof. In some embodiments, the modified silica gel composition is pulverized. The modified silica gel particles can have a pore size of 0.01 mm to 5.0 mm, a pore size of 1.5 nm to 7 nm, or a combination thereof. In another embodiment, the modified silica gel granules can have a pore size of 1.5 nm to 5 nm, a pore size of 0.5 mm to 5 mm, or a combination thereof. The modified silica gel powder can have a pore size of 5 nm to 7 nm, a pore size of 0.03 mm to 0.08 mm, or a combination thereof. The weight ratio of the modified silica gel composition to the pyrolysis oil is 0.005 to 1. The contacting conditions can include a temperature of 10°C to 100°C, a pressure of 0.101 MPa to 1 MPa, a contact rate of 0.1 bed volumes per hour (BV / h) to 5 BV / h, or a combination thereof. In some embodiments, the modified silica gel composition can include cobalt chloride. A mixture of unmodified silica gel and cobalt-modified silica gel (e.g., CoCl2 silica or iron complex) can also be used in the process of the present invention. In one preferred embodiment, the modified silica gel composition is in a dehydrated form. In a preferred embodiment, the modified silica gel can be dehydrated CoCl2 silica. The modified silica gel composition can be regenerated (e.g., by heating the modified silica gel composition).In addition to siloxanes, contacting a modified silica gel composition with a waste plastic pyrolysis oil composition can reduce the total level of heteroatom-containing compounds (e.g., by at least 50% by weight). For example, this process can reduce the amount of oxygen-containing compounds by at least 50% by weight compared to the same waste plastic pyrolysis oil composition not contacted with the modified silica gel composition. The amount of total organic nitrogen-containing compounds can be reduced by at least 50%, at least 80%, or at least 90% by weight compared to the same waste plastic pyrolysis oil composition not treated with the modified silica gel composition. Chloride-containing compounds can be reduced by at least 50%, at least 60% by weight compared to the same waste plastic pyrolysis oil composition not treated with the modified silica gel composition, and chloride compounds include inorganic chloride compounds and organic chloride compounds.

[0010] The following contains definitions of various terms and phrases used throughout this specification.

[0011] The terms "about" or "approximately" are defined as close to what would be understood by one of ordinary skill in the art. In one non-limiting embodiment, the term is defined as within 10%, preferably within 5%, more preferably within 1%, and most preferably within 0.5%.

[0012] The terms "wt %, "vol %", or "mole %" refer to the weight, volume, or mole % of a component based on the total weight, volume, or moles of the material containing that component, respectively. In one non-limiting example, 10 moles of a component in 100 moles of a material is 10 mole % of the component.

[0013] The term "substantially" and variations thereof are defined to include ranges of within 10%, within 5%, within 1%, or within 0.5%.

[0014] The terms "inhibiting," or "reducing," or "preventing," or "avoiding," or any variation of these terms, as used in the claims and / or this specification, include any measurable reduction or complete inhibition to achieve a desired result.

[0015] The term "effective," as that term is used in this specification and / or the claims, means sufficient to accomplish a desired, expected, or intended result.

[0016] The term "gums" refers to solid, creamy, and / or semi-solid portions gradually removed from liquid pyrolysis oil (pyrolysis oil). In embodiments of the present invention, "gums" can include components with an average molecular weight of 400 Daltons that are soluble or pulverized from the solution and / or liquid. Many pyrolysis gasolines, especially unrefined gasolines, can contain gums in the form of thick, resinous deposits that accumulate under certain conditions. For example, when left in the dark or under diffuse light conditions for a long period of time, a semi-liquid substance called "gums" is often observed gradually accumulating at the bottom of the oil as a brown, sticky mass. Another example of "gums" can include the dark brown, hard, resinous residue that can be obtained by evaporating liquid products, including pyrolysis gasoline and / or pyrolysis oil, in a copper pan.

[0017] The term "stability" refers to a pie oil composition that does not change over time due to chemical reactions. In embodiments of the present invention, "stability" can mean that the reactivity of the (adsorbent-treated) pie oil is limited or nonexistent due to the washing / capture of reactive substances by the adsorbent. As a result, there is substantially no or no gum formation or other color changes, and the properties after purification remain unchanged over time.

[0018] The use of the terms "a" or "an" in the claims or this specification when used in conjunction with the terms "comprising," "including," "containing," or "having" can mean "one," but is also consistent with the meanings of "one or more," "at least one," and "one or more."

[0019] The words "comprising" (and any form of "comprising", such as "comprise" and "comprises"), "having" (and any form of "having", such as "have" and "has"), "including" (and any form of "including", such as "includes" and "include"), or "containing" (and any form of "containing", such as "contains" and "contain") are inclusive or open-ended and do not exclude additional, unrecited elements or method steps.

[0020] The process of the present invention can "comprise," "consist essentially of," or "consist of" specific ingredients, components, compositions, etc., as disclosed throughout this specification. In one non-limiting embodiment, with regard to the provisional phrase "consist essentially of," a fundamental and novel feature of the process of the present invention is its ability to reduce the amount of siloxanes in waste plastic pyrolysis oil in a cost- and energy-efficient manner.

[0021] The term "primarily" refers to greater than any of 50% by weight, 50% by mole, and 50% by volume. For example, "primarily" can include 50.1% to 100% by weight, and all values ​​and ranges therebetween, 50.1% to 100% by mole, and all values ​​and ranges therebetween, or 50.1% to 100% by volume, and all values ​​and ranges therebetween.

[0022] Other objects, features, and advantages of the present invention will become apparent from the following drawings, detailed description, and examples. It should be understood, however, that the drawings, detailed description, and examples, while indicating specific embodiments of the present invention, are given by way of illustration only and are not meant to be limiting. In addition, it is contemplated that various changes and modifications within the spirit and scope of the present invention will become apparent to those skilled in the art from this detailed description. In further embodiments, features from a particular embodiment can be combined with features from other embodiments. For example, features from one embodiment can be combined with features from any of the other embodiments. In further embodiments, additional features may be added to the specific embodiments described herein. [Brief explanation of the drawings]

[0023] Advantages of the present invention will become apparent to those skilled in the art with the benefit of the following detailed description and by reference to the accompanying drawings.

[0024] [Figure 1] 1 shows a schematic diagram of a system for refining waste plastic pyrolysis oil according to an embodiment of the present invention. [Figure 2] 1 shows a visual comparison of untreated and treated pie oil using activated carbon, molecular sieves, and CoCl2 modified silica gel granules of the present invention. [Figure 3] 1 shows X-ray fluorescence data of untreated and treated pie oil using activated carbon, molecular sieves, and CoCl2-modified silica gel granules of the present invention. [Figure 4A] Figure 1 shows the 1-H NMR-based analysis of Si-species in raw and CoCl2-modified silica gel-treated pie oil. [Figure 4B] FIG. 1 shows 1-H NMR-based analysis of Si-species in untreated and CoCl2-modified silica gel-treated pie oil. [Figure 5] Figure 1 shows the contour plot of two-dimensional gas chromatograph (GC × GC) revealing the reduction of oxyacid salts in pie oil after treatment with CoCl2-modified silica gel granules. [Figure 6A] This is a visual observation of three different pie oils along with the same pie oil treated with silica gel granules, crushed silica gel granules, and silica gel powder. [Figure 6B] This is a visual observation of three different pie oils along with the same pie oil treated with silica gel granules, crushed silica gel granules, and silica gel powder. [Figure 6C] Figure 6 shows visual observations of three different Pi Oils, along with the same Pi Oil treated with silica gel granules, crushed silica gel granules, and silica gel powder. From left to right, Figure 6A shows untreated Pi Oil 1 (raw material), Pi Oil 1 treated with CoCl-containing silica gel granules, Pi Oil 1 treated with crushed CoCl-containing silica gel granules, and Pi Oil 1 treated with silica gel powder; Figure 6B shows untreated Pi Oil 2 (raw material), Pi Oil 2 treated with CoCl-silica gel granules, Pi Oil 2 treated with crushed CoCl-silica gel granules, and Pi Oil 2 treated with silica gel powder; and Figure 6C shows untreated Pi Oil 3 (raw material), Pi Oil 3 treated with CoCl-silica gel granules, Pi Oil 3 treated with crushed CoCl-silica gel granules, and Pi Oil 3 treated with silica gel powder. [Figure 7] FIG. 1 is a graph comparing the total Si-, Cl-, and TON contents of untreated pie oil and the same pie oil treated with silica gel granules, crushed silica gel granules, and silica gel powder. [Figure 8] 1 shows a comparative XRF spectrum of the elements cobalt and chlorine in a CoCl2-modified silica gel composition of the present invention. [Figure 9] CoCl2 silica gel (left) and hydrated CoCl2 silica gel (right) are shown.

[0025] While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings, which may not be to scale. DETAILED DESCRIPTION OF THE INVENTION

[0026] Currently, pie oil, particularly pie oil derived from the pyrolysis of plastics, has a high siloxane content and / or gum or gum precursor content. This can be harmful to the equipment and materials used in storing, transporting, and / or processing the pie oil (e.g., shortened catalyst life, increased gum formation, decreased pie oil stability, and increased pie oil acidity). Therefore, storing, transporting, and / or processing pie oil in chemical plants is very difficult. For this reason, pie oil is often burned as fuel in chemical plants. A discovery has been made that provides at least one solution to at least some of these problems. The method involves contacting waste plastic pyrolysis oil with a modified silica gel composition to remove siloxanes from the pie oil, thereby reducing compounds that can poison catalysts and thus shorten catalyst life. This process can also remove gums by removing gum precursors. Therefore, the stability of the pie oil for storage, transportation, and / or further processing can be significantly improved. The refined pie oil produced by the process of the present invention can be used in cracking processes to produce high value chemicals such as olefins, including light olefins (C2-C4 olefins), C5+ olefins, and / or aromatics such as benzene, toluene, and xylene.

[0027] These and other non-limiting aspects of the present invention are discussed in further detail in the following sections with reference to the figures.

[0028] A. Modified silica gel composition and waste plastic pyrolysis oil The modified silica gel composition can include CoCl2 silica gel, iron-complexed silica gel, or a mixture thereof. In some embodiments, the modified silica gel is a mixture of unmodified silica gel and modified silica gel. Silica gel compositions are commercially available (e.g., Sigma-Aldrich® (USA), AGM Container Controls, Inc. (Tucson, AZ, USA), ChemPoint (USA), etc.). The modified silica gel composition can be in the form of particles, granules, powder, or a mixture thereof. The modified silica gel composition can be crushed before use. The modified silica gel composition(s) can have a pore size and diameter. The pore size of the modified silica gel composition particles can be 0.01 mm to 5.0 mm, or 0.01, 0.05, 0.1, 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5 mm, or any range or value therebetween. The pore size of the modified silica gel composition particles can be 1.5 nm to 7 nm, or 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5, 7.0 nm, or any range or value therebetween. The modified silica gel composition granules can have a pore size of 0.5 mm to 5 mm, or 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5 mm, or any range or value therebetween. The pore size of the modified silica gel composition granules can be 1.5 nm to 5 nm, or 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5 mm, or any range or value therebetween. The modified silica gel composition powder can have a pore size of 0.03 mm to 0.08 mm, or 0.03, 0.04, 0.05, 0.06, 0.07, 0.08 mm, or any range or value therebetween. The pore size of the modified silica gel composition powder can be 5 nm to 7 nm, or 5, 5.5, 6, 6.5, 7 nm, or any value or range thereof. The unmodified silica can include silica gel or silica hydrogel.

[0029] The modified silica gel composition was 200 ml 2 / g~1200m 2 / g, and all ranges and values ​​therebetween. For example, 200 m 2 / g, 300m 2 / g, 400m2 / g, 500m 2 / g, 600m 2 / g, 700m 2 / g, 800m 2 / g, 900m 2 / g, 1000m 2 / gm, 1100m 2 / g, 1200m 2 / g, and all ranges and values ​​therebetween.

[0030] The modified silica gel composition can capture, adsorb, and / or remove at least some of one or more of (a) acyclic siloxanes, cyclic siloxanes, or a combination thereof, (b) oxygen-containing compounds, (c) nitrogen-containing compounds, (d) chloride-containing compounds, (e) polynuclear aromatic compounds and heavy tails (C20+), and (f) heavy metals from waste plastic pyrolysis oil, thereby removing gums and / or gum precursors from the pyrolysis oil and increasing the stability of the pyrolysis oil. In embodiments of the present invention, the adsorbent can further remove other heteroatom-containing compounds that are not gums or gum precursors. In embodiments of the present invention, the adsorbent can also remove other oxygen-containing compounds, nitrogen-containing compounds, and chloride-containing compounds that are not gums or gum precursors.

[0031] Non-limiting examples of acyclic siloxanes include hexamethyldisiloxane, octamethyltrisiloxane, decamethyltetrasiloxane, dodecamethylpentasiloxane, tetradecamethylhexasiloxane, etc. Non-limiting examples of cyclic siloxanes include hexamethylcyclotrisiloxane, octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane, dodecamethylcyclohexasiloxane, etc.

[0032] Non-limiting examples of oxygen- and / or nitrogen-containing compounds include fatty acids, aromatic acids, nitriles, amines, aldehydes, aliphatic / cyclic ketones, cyclic amides, aliphatic / aromatic alcohols, diols, esters, ethers, aliphatic / cyclic chlorides, furans, indoles, quinolines, phenolic compounds, indole compounds, acidic compounds, alcohols, amines, or combinations thereof. The oxygen- and / or nitrogen-containing compounds can include 2-heptadecanone, 2-pentanone, caprolactam, 3-heptanol, methyl (iso-2), octadecanenitrile, oleaninitrile, cyclopentanone, tridecanenitrile, heptanoic acid, dodecanophenone, 2-cyclopentenol, 1-butanol, benzoic acid, hexanenitrile, tridecanenitrile, 2-cyclopenten-1-one, 2-hydroxy-3-m, phenol, C5-substituted (iso-2) 2-cyclopenten-1-one, 3-ethyl-2-hydrogen, or combinations thereof.

[0033] Non-limiting examples of chloride-containing compounds can include 1,2-dichloroethane, ethanol, 2-chloroacetic acid, 2,chloroethanol, ethanol, 2-(2-chloroethoxy), benzene, (2-chloroethoxy), or combinations thereof.

[0034] Scheme I shows a representation of the proposed mechanism of action for removing siloxanes using the modified silica gel composition of the present invention. At the surface of the modified silica gel composition, hydrogen bonding (triangles) can occur between the Si-O-Si bonds of the siloxane backbone and the silanol groups. This interaction, at approximately 10 kJ / mol, is lower than covalent bonding but may be stronger than van der Waals interactions. This interaction can lead to ring opening, forming linear siloxanes. Cleavage of the Si-O bond (wavy line) can be advantageously enhanced under the acidic aqueous solution conditions attached to the silica gel. At higher loadings, polymerization of short linear chains into polydimethylsiloxanes can be promoted by molecular proximity. TIFF2025533982000002.tif88168

[0035] When cobalt chloride is incorporated into the modified silica gel composition, it can form adducts that are octahedral or tetrahedral in structure. For example, octahedral complexes can be formed with nitrogen-containing compounds, and tetrahedral complexes can be formed with phosphorus-containing compounds. This is exemplified by reactions (1) with pyridine and (2) with triphenylphosphine. In some cases, nitrogen-containing compounds can form salts of the anionic complex CoCl4, as shown in reaction (3) using tetraethylammonium chloride as an example. CoCl2 can also be chelated with alkylsilanes, as shown in reaction (4) using chlorotrimethylsilane as an example. Other heteroatom removals can involve hydrogen bonding between the compound and silanol groups on the silica gel surface in the presence of small amounts of water. CoCl2·6H2O +4 C5H5N → CoCl2(C5H5N)4+6 H2O(1). CoCl2·6H2O +2 P(C6H5)3→ CoCl2[P(C6H5)3]2+6 H2O(2). CoCl2+2[(C2H5)4N]Cl→[(C2H5)4N)]2[CoCl4](3) CoCl2·6H2O +12 (CH3)3SiCl → CoCl2+6[(CH3)3SiCl]2O +12HCl(4).

[0036] In some embodiments, the modified silica gel composition can include iron(II) tetrasulfophthalocyanine adsorbed onto silica gel modified with iron chloride (Fe), e.g., FeCl on silica gel powder, 1,10-phenanthroline, or 3-n-propylpyridinium chloride.

[0037] In some embodiments, the modified silica gel composition is regenerative. For example, a used modified silica gel composition can be sublimed under vacuum at temperatures between 20°C and 400°C, or 20°C, 50°C, 100°C, 125°C, 150°C, 175°C, 200°C, 225°C, 250°C, 275°C, 300°C, 325°C, 350°C, 375°C, 400°C, or any range or value therebetween.

[0038] Waste plastic pyrolysis oil can be obtained from commercial sources. Non-limiting examples of commercial sources include Enrestec, Inc. (Taiwan), Beston Group Co. (China), Henan Dong Environmental Technology Inc. (China), New Hope Energy (USA), and Agile Process Chemicals (India). The waste plastic pyrolysis oil can have a boiling point temperature of 20°C to 500°C (e.g., 20°C to 500°C, 40°C to 450°C, 50°C to 400°C, 55°C to 300°C, or any range or value therebetween). The waste plastic pyrolysis oil can have a molecular weight of 100 g / mol to 500 g / mol, or 100 g / mol, 150 g / mol, 200 g / mol, 250 g / mol, 300 g / mol, 350 g / mol, 400 g / mol, 450 g / mol, 500 g / mol, or any value or range therebetween.

[0039] B. System and method for refining waste plastic processing oil FIG. 1 shows an overview of a process for refining waste plastic pyrolysis oil using the method of the present invention. The system 100 can include a refining unit 102. A waste plastic pyrolysis oil feed 104 can enter the refining unit 102. The waste plastic pyrolysis oil can include pyrolysis oil derived from the pyrolysis of mixed plastics. The pyrolysis oil can have a boiling point range of 20°C to 600°C. In an embodiment of the present invention, the waste plastic pyrolysis oil feed 104 can flow directly into the refining unit 102 without any pretreatment (e.g., alkaline washing, etc.). In an embodiment of the present invention, the adsorbent in the refining unit 102 does not contain any chemicals.

[0040] The purification unit 102 can be any known unit (e.g., a packed column, a pressure swing unit, a tank, etc.). For example, the purification unit 102 can include a guard bed, a purification column, a fluidized bed, a stirred tank, or a combination thereof. The adsorbent in the purification unit 102 can be in a fixed bed and / or a fluidized bed, or dispersed in a stirred tank. For example, the purification unit 102 can include one or more absorption beds packed with the modified silica gel composition of the present invention, and optionally, other beds can include one or more types of absorbent. Other types of absorbents that can be used in conjunction with the modified silica gel composition of the present invention include activated carbon, molecular sieves, bleaching clay, ionic resins, hardened eggshell powder, and combinations thereof. Non-limiting examples of molecular sieves that can be used in conjunction with the modified silica gel composition of the present invention include K 12 [(AlO2)12(SiO2)12]·nH2O 、 Na 12 [(AlO2)12(SiO2) 12 ]·nH2O, Ca 4,5 [(AlO2) 12 (SiO2) 12 ]·nH2O, Na 86 [(AlO2) 86 (SiO2) 106 ]·nH2O, or combinations thereof. The molecular sieve can have a pore size of 3-10 Å, as well as all ranges and values ​​therebetween, including 3-4 Å, 4-5 Å, 5-6 Å, 6-7 Å, 7-8 Å, 8-9 Å, and 9-10 Å. The molecular sieve can be in the form of granules, flakes, beads, powder, or combinations thereof. When activated carbon is used in conjunction with the modified silica gel composition, the activated carbon can have a pore size in the range of 1-100 Å, a surface area of ​​10-8000 m2 / g, or combinations thereof.

[0041] The contact conditions for purifying waste plastic pyrolysis oil can include temperature and / or pressure. The contact temperature can be in the range of 10 to 100°C, as well as all ranges and values ​​therebetween, including 10 to 20°C, 20 to 30°C, 30 to 40°C, 40 to 50°C, 50 to 60°C, 60 to 70°C, 70 to 80°C, 80 to 90°C, and 90 to 100°C. The contact pressure can be in the range of 0.01 MPa to 1 MPa, or 0.01 MPa, 0.05 MPa, 0.1 MPa, 0.25 MPa, 0.5 MPa, 0.75 MPa, 1 MPa, or all ranges and values ​​therebetween. When an absorption bed is employed, the contact conditions are 0.1 to 10 hr -1 , as well as 0.1~0.5hr-1, 0.5~1hr-1, 1~2hr -1 , 2~4 hours -1 , 4~6 hours -1 , 6~8 hours -1 and 8 to 10 hours -1 The present invention can include weight hourly space velocities of all ranges and values ​​therebetween, including the ranges of

[0042] In some embodiments, the purification unit 102 can be a tank / reactor equipped with a stirring device. The waste plastic pyrolysis oil, the modified silica gel composition, and any other adsorbents can be dispersed in the stirred tank and mixed for 1 minute to 10 hours, and all ranges and values ​​therebetween, including 1 minute to 10 minutes, 10 minutes to 30 minutes, 30 minutes to 1 hour, 1 hour to 2 hours, 2 hours to 3 hours, 3 hours to 4 hours, 4 hours to 5 hours, 5 hours to 6 hours, 6 hours to 7 hours, 7 hours to 8 hours, 8 hours to 9 hours, and 9 hours to 10 hours.

[0043] In the refining unit 102, the waste plastic pyrolysis oil feed 104 can be contacted with the modified silica gel composition of the present invention to produce refined waste plastic pyrolysis oil 106. The refined waste plastic pyrolysis oil 106 exits the absorption unit 102 and can be transported, stored, processed in other units, or a combination thereof. For example, the adsorbent unit 102 can be located upstream of a hydrocracking unit and / or a cracking unit. The refined waste plastic pyrolysis oil 106 can contain at least 50%, 60%, 70%, 80%, 90%, 99% less siloxanes by weight, or any range or value therebetween, compared to the same waste plastic pyrolysis oil composition that has not been processed or treated in the refining unit 102. The total organic nitrogen-containing compound content in the refined waste plastic pyrolysis oil 106 can be at least 50%, 60%, 70%, 80%, 90%, 99% by weight less than the total nitrogen-containing compound content of the same waste plastic pyrolysis oil composition that has not been processed or treated in the refining unit 102, or any range or value therebetween. The oxygen-containing compound content in the refined waste plastic pyrolysis oil 106 can be at least 50%, 60%, 70%, 80%, 90%, 99% by weight less than the oxygen-containing compounds of the same waste plastic pyrolysis oil composition that has not been processed or treated in the refining unit 102, or any range or value therebetween. The refined waste plastic pyrolysis oil 106 can have at least 50%, 60%, 70%, 80%, 90%, 99% by weight less chloride content, or any range or value therebetween, compared to the same waste plastic pyrolysis oil composition that has not been processed or treated in the refining unit 102.In some embodiments, the total amount of siloxanes, total organic nitrogen-containing compounds, oxygen-containing compounds, and chloride-containing compounds can be at least 50%, 60%, 70%, 80%, 90%, 99% by weight less, or any range or value therebetween, than the total amount of siloxanes, total organic nitrogen-containing compounds, oxygen-containing compounds, and chloride-containing compounds in the same waste plastic pyrolysis oil composition that has not been processed or treated in the purification unit 102. The refined waste plastic pyrolysis oil 106 can be less dense or lighter in color than the waste plastic pyrolysis oil feed 104 prior to contact with the modified silica gel composition of the present invention.

[0044] According to embodiments of the invention, system 100 can include an adsorbent regeneration unit configured to regenerate adsorbent (saturated or partially saturated) from purification unit 102 to remove gums and / or gum precursors and produce a regenerated adsorbent. As an alternative to, or in addition to, the adsorbent regeneration unit, the adsorbent (saturated or partially saturated) can be regenerated in purification unit 102 when the purification unit is inactive. In embodiments of the invention, at least a portion of the saturated or partially saturated adsorbent in purification unit 102 can be discarded without regeneration. Regeneration can include heating (thermal regeneration) the saturated or saturated adsorbent, vacuum and thermal regeneration, rinsing with a strong acid or strong base solution, and / or rinsing with a polar organic solvent (e.g., tetrahydrofuran (THF)).

[0045] The following specific examples are included as part of this disclosure. These examples are for illustrative purposes only and are not intended to limit the invention. Those of ordinary skill in the art will readily recognize parameters that can be changed or modified to yield essentially the same results.

[0046] Example 1 Treatment of Pi Oil with Modified Silica Gel Compositions and Comparative Absorbents General Methods. Comparative adsorbents of the present invention, CoCl-modified silica gel granules / powder, activated carbon, and molecular sieves (2 g each), were added to waste plastic pyrolysis oil (pie oil, 10 mL each). Each sample was stored for a certain period of time and tested for changes in color, siloxane content, chloride content, oxygen content, and nitrogen content. Si and Cl content were measured by X-ray fluorescence spectroscopy (XRF), and Si-specific and total Si content were confirmed by NMR. Total organic nitrogen content was measured by isocratic gas chromatography with a chemiluminescence detector (GC-NCD) system. The oxygenate composition and paraffin, isoparaffin, olefin, and naphtha (PIONA) composition were evaluated by comprehensive two-dimensional gas chromatography (GC×GC). The GC×GC-FID instrument setup consisted of an Agilent GC and a JEOL-TOFMS system equipped with a cryogenic thermal loop modulator ZX-1. Agilent Chemstation software was used for data acquisition and GCImage software for data analysis and visualization.

[0047] Results: Comparison of the reduction of Si-Cl-, O-, and N- impurities by various absorbents. As shown in Figure 2, compared to untreated pie oil, activated carbon, molecular sieve, and silica gel treated pie oil samples exhibited lighter colors. XRF-based chemical analysis, total organic nitrogen (TON) (Figure 3), showed significant reductions in Cl- and total organic nitrogen (TON), especially for these absorbents. However, silica gel significantly reduced Si- as well as Cl- and TON.

[0048] Detailed 1H-NMR-based analysis of Si species, shown in Figures 4A and 4B, reveals that the cyclic siloxanes (peaks D3 (hexamethylcyclotrisiloxane), D4 (octamethylcyclotetrasiloxane), and D5 (decamethylcyclopentasiloxane)) abundant in the raw material pi-oil were significantly removed by silica gel treatment. These results are consistent with the XRF-based Si measurements shown in Figure 2. The Si removal efficiency was 77 wt. % as determined by XRF, while 1H-NMR indicated 86 wt. % removal.

[0049] Detailed heteroatom specificity based on comprehensive GC (GC × GC) shown in Figure 5 confirmed the removal of oxyacid salts from pie oil after treatment with the modified silica gel composition of the present invention.

[0050] Example 2 Treatment of Pi-Oil with Various Modified Silica Gel Compositions of the Invention To elucidate the effectiveness of various silica gels, three types of silica gel were investigated for removing siloxanes, Cl-, and TON using the procedure described in Example 1, including cobalt chloride-modified silica gel granules, crushed silica gel granules, and silica gel powder commonly used for chromatographic purposes. Three different pie oils, differing in source and composition, were also examined. Visual observation (Figure 6) clearly demonstrated that all silica gels tested exhibited bright colors, indicative of removal of heteroatom-containing compounds. The pie oils had boiling points ranging from 40°C to 450°C and molecular weights ranging from 100 g / mol to 200 g / mol.

[0051] The XRF-based chemical analysis of Si-, Cl-, and TON (Figure 7) revealed that all tested silicates significantly removed Si-, Cl-, and TON. Furthermore, the results indicated that the crushed cobalt chloride-modified silica gel performed slightly better than the granules, likely due to the increased surface area and wider pores that increased the diffusion rate. However, as shown in Table 1, for the highly contaminated sample 1, the removal rates of certain groups, especially Cl-, were low in terms of percent removal but actually high in terms of adsorbent loading. Furthermore, the contents of different types of impurities exhibited competitive behavior. In other words, when various contaminant groups were present, these groups competed with each other and affected each other's adsorbent loading. [Table 1]

[0052] Example 3 Analysis of the Modified Silica Gel Composition of the Present Invention XRF-based elemental analysis of the various silica gels used detected approximately 1% cobalt chloride in the modified silica gel but not in the regular silica gel, as shown in Table 2 and Figure 8. The dehydrated CoCl2 is blue, whereas the hydrated cobalt chloride is pink, which is easily distinguishable and reversible by heating the hydrated CoCl2 silica gel, as shown in Figure 9. [Table 2]

Claims

1. 1. A process for reducing siloxanes in a waste plastic pyrolysis oil composition, the process comprising contacting the waste plastic pyrolysis oil composition with a modified silica gel composition under conditions sufficient to produce a purified waste plastic pyrolysis oil composition having at least 50% less siloxanes by weight, preferably at least 60% less siloxanes by weight, compared to the waste plastic pyrolysis oil composition that has not been contacted with the modified silica gel composition, wherein the siloxanes preferably comprise acyclic siloxanes, cyclic siloxanes, or a combination thereof, and the modified silica gel composition comprises cobalt or iron.

2. 10. The process of claim 1, wherein the modified silica gel composition comprises silica gel particles having a pore diameter of 0.01 mm to 5.0 mm, a pore size of 1.5 nm to 7 nm, or a combination thereof.

3. 3. The process of any one of claims 1 to 2, wherein the modified silica gel composition comprises silica gel granules having a pore size of 1.5 nm to 5 nm, a pore size of 0.5 mm to 5 mm, or a combination thereof.

4. 3. The process of any one of claims 1 to 2, wherein the modified silica gel composition comprises silica gel powder granules having a pore size of 5 nm to 7 nm, a pore diameter of 0.03 mm to 0.08 mm, or a combination thereof.

5. The process of any one of claims 1 to 2, wherein the modified silica gel composition is pulverized.

6. 3. The process of any one of claims 1 to 2, wherein the contacting conditions comprise a temperature of from 10°C to 100°C, a pressure of from 0.101 MPa to 1 MPa, and / or a contacting rate of from 0.1 bed volumes per hour (BV / h) to 5 BV / h, or a combination thereof.

7. 3. The process of any one of claims 1 to 2, wherein the modified silica gel composition comprises unmodified silica gel.

8. The process according to any one of claims 1 to 2, wherein the pyrolysis oil further contains oxygen-containing compounds, and the oxygen-containing compounds are reduced by at least 50% by weight by contacting the pyrolysis oil with the modified silica gel composition, compared to the waste plastic pyrolysis oil composition that has not been contacted with the modified silica gel composition.

9. The process according to any one of claims 1 to 2, wherein the pyrolysis oil further contains organic nitrogen-containing compounds, and the contact with the modified silica gel composition reduces the total organic nitrogen-containing compounds by at least 50% by weight, at least 80% by weight, or at least 90% by weight, compared to the waste plastic pyrolysis oil composition that has not been contacted with the modified silica gel composition.

10. The process according to any one of claims 1 to 2, wherein the pyrolysis oil further contains chloride-containing compounds, and the chloride content is reduced by at least 50% by weight, at least 60% by weight, by contact with the modified silica gel composition, compared to the waste plastic pyrolysis oil composition that has not been contacted with the modified silica gel composition, and the chloride compounds include inorganic chloride compounds and organic chloride compounds.

11. The process according to any one of claims 1 to 2, wherein the pyrolysis oil further contains oxygen-containing compounds, organic nitrogen-containing compounds, and / or chloride-containing compounds, and the total amount of oxygen-containing compounds, organic nitrogen-containing compounds, and / or chloride-containing compounds is reduced by at least 50% by weight by contacting the pyrolysis oil with the modified silica gel composition, compared to the waste plastic pyrolysis oil composition that has not been contacted with the modified silica gel composition.

12. 3. The process of any one of claims 1 to 2, wherein the weight ratio of the modified silica gel composition to the pyrolysis oil is 0.005 to 1.

13. 3. The process of any one of claims 1 to 2, further comprising regenerating the modified silica gel composition.

14. The process of any one of claims 1 to 2, wherein the modified silica gel composition is in a dehydrated form.

15. The modified silica gel composition comprises CoCl ２ The process according to any one of claims 1 to 2, wherein the silica is silica.

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