Pretreatment of plastic pyrolysis oil

Abstract

A process for converting waste plastics into refinery feedstock, the process comprising: pyrolysis of a plastic feedstock, including waste plastics, to produce a liquid stream of plastic pyrolysis oil; feeding the liquid stream of plastic pyrolysis oil directly to an adsorption-based refining process to produce a treated plastic pyrolysis oil stream; and collecting the treated plastic pyrolysis oil stream from the adsorption vessel for further processing into value-added products as feedstock for conventional refining processes. The adsorption-based refining process comprises contacting the liquid stream of plastic pyrolysis oil with one or more adsorbents in an adsorption vessel, at least one of which is adapted to adsorb organic molecules having heteroatoms of each of sulfur, nitrogen, oxygen, and chlorine. Such a system may be integrated with conventional refining equipment.

Description

Description of Related Applications

[0001] This application claims the benefit of U.S. Patent Application No. 17 / 668,487, filed February 10, 2022, the entire disclosure of which is incorporated herein by reference. [Technical field]

[0002] The present disclosure relates to a process for converting waste plastics into refinery feedstocks. More specifically, certain embodiments of the present disclosure relate to a process for converting waste plastics into refinery feedstocks by removal of organic molecules with heteroatoms through a specific adsorption-based purification process. [Background technology]

[0003] Plastics are synthetic or semi-synthetic organic polymers composed primarily of carbon and hydrogen. In addition, plastics tend to be durable with slow decomposition rates, so they remain in the environment for long periods of time and are less likely to degrade rapidly upon disposal. Pure plastics are generally insoluble in water and non-toxic. However, additives used in the preparation of plastics can be toxic and leach into the environment. An example of a toxic additive is phthalate ester. Other types of additives include fillers, colorants, plasticizers, stabilizers, antioxidants, flame retardants, ultraviolet (UV) radiation absorbers, antistatic agents, foaming agents, and lubricants used during preparation to alter the composition and properties.

[0004] Plastics are pyrolyzed at high temperatures and the polymers can be converted back to their original monomers as gases or liquids and recovered. However, additives added to plastics during production pose a challenge to effectively utilize the products recovered from pyrolysis. During pyrolysis, the additives become pyrolysis products. Summary of the Invention [Problem to be solved by the invention]

[0005] Thus, there is clearly a long-standing need to provide a solution for utilizing the pyrolysis products produced by the thermal decomposition of plastics. In order to utilize such pyrolysis products, the residues left by the additives in the pyrolysis products must be removed. [Means for solving the problem]

[0006] According to one or more embodiments of the present disclosure, a process for converting waste plastics into refinery feedstock is disclosed, which includes the steps of: (a) pyrolysis of a plastic feedstock, including waste plastics, to produce a liquid stream of plastic pyrolysis oil, a tail gas stream, and a solid stream; (b) feeding the liquid stream of plastic pyrolysis oil directly to an adsorption-based refining process to produce a treated plastic pyrolysis oil stream containing less than 10 ppmw nitrogen, less than 10 ppmw sulfur, less than 10 ppmw chlorine, and less than 10 ppmw oxygen; and (c) collecting the treated plastic pyrolysis oil stream from the adsorption vessel for further processing into value-added products as feedstock for conventional refining processes. The adsorption-based purification process includes the steps of: i) contacting a liquid stream of plastic pyrolysis oil with one or more adsorbents in an adsorption vessel, the adsorbents being configured to adsorb organic molecules that contain one or more atoms of sulfur, nitrogen, oxygen, or chlorine, where at least one of the one or more adsorbents is configured to adsorb organic molecules that contain each of sulfur, nitrogen, oxygen, and chlorine; and ii) discharging the treated plastic pyrolysis oil stream from the adsorption vessel.

[0007] Additional features and advantages of the described embodiments are set forth in the detailed description which follows, and in part will become readily apparent to those skilled in the art from the description, or may be learned by practice of the described embodiments, including the following detailed description and drawings, and claims. [Brief description of the drawings]

[0008] The following detailed description of specific embodiments of the present disclosure can be best understood when read in conjunction with the following drawings. [Figure 1] FIG. 1 is a schematic diagram of one or more embodiments of the present disclosure. [Diagram 2] FIG. 1 is a schematic diagram of one or more embodiments of the present disclosure in which one adsorption vessel is utilized. [Diagram 3] Schematic diagram of one or more embodiments of the present disclosure in which a series of adsorption vessels is utilized. [Figure 4] Schematic diagram of one or more embodiments of the present disclosure in which parallel adsorption vessels are utilized. [Diagram 5] FIG. 1 is a schematic diagram of one or more embodiments of the present disclosure in which parallel adsorption paths of adsorption vessels in series are utilized. Reference will now be made in detail to various embodiments, some of which are illustrated in the accompanying drawings. Whenever possible, the same reference numbers will be used throughout the drawings to refer to the same or similar units. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] An embodiment of a process for converting waste plastics into refinery feedstocks combined with associated systems is provided in this disclosure.

[0010] The process for converting waste plastics into refinery feedstock includes pyrolysis of a plastic feedstock, including waste plastics, to produce a liquid stream of plastic pyrolysis oil, a tail gas stream, and a solid stream; feeding the liquid stream of plastic pyrolysis oil directly to an adsorption-based refining process to produce a treated plastic pyrolysis oil stream containing less than 10 ppmw of nitrogen, less than 10 ppmw of sulfur, less than 10 ppmw of chlorine, and less than 10 ppmw of oxygen; and collecting the treated plastic pyrolysis oil stream from the adsorption vessel for further processing into value-added products as feedstock for conventional refining processes. The adsorption-based refining process includes contacting the liquid stream of plastic pyrolysis oil with one or more adsorbents in the adsorption vessel, and discharging the treated plastic pyrolysis oil stream from the adsorption vessel. The adsorbents are adapted to adsorb organic molecules containing one or more atoms of sulfur, nitrogen, oxygen, or chlorine. Additionally, at least one of the one or more adsorbents is adapted to adsorb organic molecules containing each of sulfur, nitrogen, oxygen, and chlorine.

[0011] Having broadly described a process for converting waste plastics into refinery feedstocks, embodiments thereof will now be described in further detail with reference to the various figures.

[0012] Referring initially to FIG. 1, a schematic diagram of one or more embodiments of the present disclosure is provided in which waste plastics are converted into feedstock for a conventional refining process. An inlet stream 101 containing mixed plastics is fed to a plastic pyrolysis unit 110. The plastic pyrolysis unit 110 is in fluid communication with the inlet stream 101 and is operative to produce from the inlet stream 101 a liquid stream of plastic pyrolysis oil 102, a tail gas stream 104, and a solids stream 106. The liquid stream of plastic pyrolysis oil 102 is fed directly to an adsorption-based refining process 120. The adsorption-based refining process 120 is in fluid communication with the plastic pyrolysis unit 110 and is operative to produce a treated plastic pyrolysis oil stream 108 containing less than 10 parts per million by weight (ppmw) nitrogen, less than 10 ppmw sulfur, less than 10 ppmw chlorine, and less than 10 ppmw oxygen.

[0013] Plastic Raw Materials In one or more embodiments, the inlet stream 101 includes a plastic feedstock that includes mixed plastics of differing compositions. The plastic feedstock fed to the plastic pyrolysis unit 110 may be a mixture of plastics from various polymer classes. In various embodiments, the plastic feedstock may include plastics representing one or more of the polymer classes disclosed in Table 1. Specifically, the plastic feedstock may include plastics representing one or more of olefins, carbonates, aromatic polymers, sulfones, fluorinated hydrocarbon polymers, chlorinated hydrocarbon polymers, and acrylonitrile. Additionally, the plastic feedstock fed to the plastic pyrolysis unit 110 may include high density polyethylene (HDPE, e.g., about 0.93 to 0.97 grams per cubic centimeter (g / cm). 3 )), low density polyethylene (LDPE, e.g., about 0.910 g / cm 3 from 0.940 g / cm 3 ), polypropylene (PP), linear low density polyethylene (LLDPE), polystyrene (PS) and polyethylene terephthalate (PET). It will be recognized that the use of mixed plastic feedstocks allows for the recycling of plastics without the need for disaggregation of the plastics.

[0014] [Table 1]

[0015] The plastics in the inlet stream 101 may be provided in a variety of different forms. The plastics may be in powder form for smaller scale operations. The plastics may be in pellet form, such as pellets having particle sizes of 1 to 5 millimeters (mm), for larger scale operations. In further embodiments, the plastics may be provided as a shredded or ground product. Additionally, the plastics in the inlet stream 101 may be natural, synthetic, or semi-synthetic polymers. In various embodiments, the plastics in the inlet stream 101 may include waste plastics, off-spec manufacturing products, new plastic products, virgin plastic products, as well as combinations thereof.

[0016] Plastic pyrolysis The plastic pyrolysis unit 110 converts the inlet stream 101 of plastics into gas, liquid, and solid products. The liquid products are provided as an effluent from the plastic pyrolysis unit 110 as a stream of plastic pyrolysis oil 102. The gas product stream is shown broadly in FIGS. 1 through 5 as tail gas stream 104. The gas products in tail gas stream 104 may include a variety of species such as hydrogen and hydrocarbon gases (C1-C4), carbon monoxide (CO), carbon dioxide (CO2), and other acid gases. The solid product stream is shown broadly in FIGS. 1 through 5 as solids stream 106. Solids stream 106 may include pyrolysis residues resulting from additives that were added to the mixed plastics in the inlet stream 101 during the initial production of the mixed plastics.

[0017] The particular reactor used as the plastic pyrolysis unit 110 can be of different types and is not limited for purposes of this disclosure. Those skilled in the art will recognize that typical reactor types that can be used to perform the functions of the plastic pyrolysis unit 110 include tank reactors, rotary kilns, packed beds, bubbling, and circulating fluidized beds. In one or more embodiments, the pyrolysis of the waste plastic in the inlet stream 101 is carried out at a temperature of 300 to 1000° C. with or without the presence of a catalyst. In various further embodiments, the plastic pyrolysis unit 110 may operate at a temperature of 300 to 450° C., 450 to 1000° C., 450 to 750° C., 600 to 1000° C., or 750 to 1000° C. with low severity at temperatures below 450° C., high severity above 450° C. In various embodiments, the plastic pyrolysis unit 110 may operate at a pressure ranging from 1 to 100 bar (0.1 to 10 MPa), 1 to 50 bar (0.1 to 5 MPa), 1 to 25 bar (0.1 to 2.5 MPa), or 1 to 10 bar (0.1 to 1 MPa). Further, in various embodiments, the residence time of the waste plastic in the plastic pyrolysis unit 110 may be 1 to 3600 seconds, 60 to 1800 seconds, or 60 to 900 seconds.

[0018] Plastic pyrolysis oil It will be appreciated that the composition of the plastic pyrolysis oil 102 liquid stream may vary depending on the composition of the waste plastic utilized in the inlet stream 101. In particular, since additives added to plastics during production become pyrolysis products upon pyrolysis of the waste plastic, the amount and specific selection of organic molecules containing one or more atoms of sulfur, nitrogen, oxygen, or chlorine present in the plastic pyrolysis oil 102 liquid stream will be affected by the composition of the inlet stream 101. It will be appreciated, therefore, that the treatment process of plastic pyrolysis oil containing organic molecules containing one or more atoms of sulfur, nitrogen, oxygen, or chlorine present only at low levels below a threshold value according to the present disclosure will not be transferable or expected to be performed in the same manner as the process of the present disclosure for such organic molecules present at greater concentrations in the plastic pyrolysis oil 102 liquid stream.

[0019] In one or more embodiments, the liquid stream of plastic pyrolysis oil 102 may include up to 2000 ppmw sulfur. In various further embodiments, the liquid stream of plastic pyrolysis oil 102 may include up to 1800 ppmw sulfur, up to 1600 ppmw sulfur, up to 1400 ppmw sulfur, or up to 1200 ppmw sulfur. Additionally, in various embodiments, the concentration of sulfur in the liquid stream of plastic pyrolysis oil 102 may also have a lower limit of at least 3 ppmw sulfur, at least 5 ppmw sulfur, at least 10 ppmw sulfur, at least 20 ppmw sulfur, or at least 40 ppmw sulfur.

[0020] In one or more embodiments, the liquid stream of plastic pyrolysis oil 102 may include up to 5000 ppmw nitrogen. In various further embodiments, the liquid stream of plastic pyrolysis oil 102 may include up to 4000 ppmw nitrogen, up to 3500 ppmw nitrogen, up to 3000 ppmw nitrogen, or up to 2500 ppmw nitrogen. Additionally, in various embodiments, the concentration of nitrogen in the liquid stream of plastic pyrolysis oil 102 may also have a lower limit of at least 3 ppmw nitrogen, at least 5 ppmw nitrogen, at least 10 ppmw nitrogen, at least 100 ppmw nitrogen, or at least 500 ppmw nitrogen.

[0021] In one or more embodiments, the liquid stream of plastic pyrolysis oil 102 may include up to 2000 ppmw chlorine. In various further embodiments, the liquid stream of plastic pyrolysis oil 102 may include up to 1800 ppmw chlorine, up to 1500 ppmw chlorine, up to 1200 ppmw chlorine, or up to 1000 ppmw chlorine. Additionally, in various embodiments, the concentration of chlorine in the liquid stream of plastic pyrolysis oil 102 may also have a lower limit of at least 1 ppmw chlorine, at least 5 ppmw chlorine, at least 10 ppmw chlorine, at least 20 ppmw chlorine, or at least 40 ppmw chlorine.

[0022] In one or more embodiments, the liquid stream of plastic pyrolysis oil 102 may include up to 2000 ppmw oxygen. In various further embodiments, the liquid stream of plastic pyrolysis oil 102 may include up to 1900 ppmw oxygen, up to 1800 ppmw oxygen, up to 1750 ppmw oxygen, or up to 1600 ppmw oxygen. Additionally, in various embodiments, the concentration of oxygen in the liquid stream of plastic pyrolysis oil 102 may also have a lower limit of at least 3 ppmw oxygen, at least 5 ppmw oxygen, at least 10 ppmw oxygen, at least 100 ppmw oxygen, or at least 500 ppmw oxygen.

[0023] For clarity, note that the liquid stream of plastic pyrolysis oil 102 may contain each of sulfur, nitrogen, oxygen, and chlorine in the concentrations disclosed above, as well as only one, two, or a portion of three of sulfur, nitrogen, oxygen, and chlorine in the concentrations disclosed above.

[0024] Adsorption-Based Purification Processes The adsorption-based refining process 120 includes contacting the liquid stream of plastic pyrolysis oil 102 with one or more adsorbents in an adsorption vessel. The adsorbents are adapted to adsorb organic molecules containing one or more atoms of sulfur, nitrogen, oxygen, or chlorine. Furthermore, at least one of the one or more adsorbents is adapted to adsorb organic molecules containing each of sulfur, nitrogen, oxygen, and chlorine. That is, at least one of the adsorbents is adapted to adsorb sulfur-containing compounds, at least one of the adsorbents is adapted to adsorb nitrogen-containing compounds, at least one of the adsorbents is adapted to adsorb oxygen-containing compounds, and at least one of the adsorbents is adapted to adsorb chlorine-containing compounds. The adsorption of organic molecules containing each of sulfur, nitrogen, oxygen, and chlorine produces a treated plastic pyrolysis oil stream 108, which is discharged from the adsorption vessel for collection and further processing into value-added products as feedstock for conventional refining processes.

[0025] Before feeding the resulting treated plastic pyrolysis oil stream 108 to a conventional refining process to produce value-added products, it is desirable to remove organic molecules containing one or more atoms of sulfur, nitrogen, oxygen, or chlorine from the liquid stream of plastic pyrolysis oil 102, because such organic molecules may interfere with or affect the chemical reactions occurring in the conventional refining process. Value-added products such as ethylene, propylene, and butylene may be produced from pyrolysis oil and other hydrocarbon streams using conventional refining processes such as hydrotreating, hydrocracking, or fluid catalytic cracking, but residual organic molecules containing heteroatoms in the liquid stream of plastic pyrolysis oil 102 may affect the conventional refining process and the yield of such value-added products. Therefore, removing molecules containing one or more atoms of sulfur, nitrogen, oxygen, or chlorine from the liquid stream of plastic pyrolysis oil 102 before feeding the resulting treated plastic pyrolysis oil stream 108 to a conventional refining process is essential when converting waste plastics into refinery feedstocks. It is expressly noted that the presence of chlorine in process streams feeding conventional refinery processes is particularly problematic.

[0026] Adsorption is a separation technique that may be utilized to purify liquid or gas streams. When a solid is placed in contact with a gaseous or liquid compound, forces arise between the surface of the solid and the gaseous or liquid compound, forming bonds. This phenomenon is called adsorption. The bonds may have various strengths, depending on the nature of the compounds and solids involved. Different bond strengths may result in selective adsorption of only certain components in a mixture. Note that steric hindrance and kinetic phenomena may also contribute to the selectivity of the adsorption phenomenon. It is understood that this highly specific adsorption selectivity can be exploited by using a number of microporous solids with large surface areas, and therefore large adsorption capacities, as adsorbents in the adsorption vessels to fractionate mixtures or to selectively remove undesirable components from such mixtures.

[0027] Having broadly described the adsorption-based purification process 120 and separation by adsorption, embodiments of specific configurations and configurations of the adsorption-based purification process 120 are provided with reference to the various figures.

[0028] 1 adsorption vessel 2, in one or more embodiments, the adsorption-based purification process 120 includes a single adsorption vessel 122. The liquid stream of plastic pyrolysis oil 102 is fed directly into the adsorption vessel 122 and contacted with the adsorbent 130 contained therein to produce a treated plastic pyrolysis oil stream 108. In such a configuration, the adsorbent 130 contained within the single adsorption vessel 122 is adapted to adsorb sulfur-containing compounds, nitrogen-containing compounds, oxygen-containing compounds, and chlorine-containing compounds. Thus, it will be appreciated that in one or more embodiments, a single type of adsorbent 130 capable of adsorbing sulfur-containing compounds, nitrogen-containing compounds, oxygen-containing compounds, and chlorine-containing compounds is provided.

[0029] In one or more further embodiments, a plurality of different sorbents 130 are provided for adsorbing sulfur-containing, nitrogen-containing, oxygen-containing, and chlorine-containing compounds, with each sorbent 130 adsorbing one or more of sulfur-containing, nitrogen-containing, oxygen-containing, and chlorine-containing compounds. The plurality of different sorbents 130 may be provided in a homogeneous or heterogeneous manner. Specifically, in one or more embodiments, the plurality of different sorbents 130 are mixed together in an amalgam of sorbents 130, and in one or more further embodiments, the plurality of different sorbents 130 are provided as separate layers or populations within the adsorption vessel 122.

[0030] Multiple adsorption vessels in series Referring to FIG. 3, in one or more embodiments, the adsorption-based purification process 120 includes multiple adsorption vessels 122 in series, which may alternatively be referred to as series adsorption vessels 132. For clarity, the disclosure regarding the adsorption vessels 122 is fully transferable to the series adsorption vessels 132 as well. The liquid stream of plastic pyrolysis oil 102 is fed directly to the first of the series adsorption vessels 132 and contacted with the adsorbent 130 contained therein to produce an intermediate treated plastic pyrolysis oil stream 208. This intermediate treated plastic pyrolysis oil stream 208 is sent in a sequential manner to additional series adsorption vessels 132 to further process the intermediate treated plastic pyrolysis oil stream 208. The last series adsorption vessel 132 in the series of adsorption vessels 122 discharges the treated plastic pyrolysis oil stream 108. In such a configuration, the adsorbents 130 contained within the series adsorption vessels 132 are jointly adapted to adsorb sulfur-containing compounds, nitrogen-containing compounds, oxygen-containing compounds, and chlorine-containing compounds.

[0031] It will be appreciated, therefore, that in one or more embodiments, a type of sorbent 130 is provided in each of the series adsorption vessels 132, with each sorbent 130 capable of adsorbing one or more of sulfur-containing compounds, nitrogen-containing compounds, oxygen-containing compounds, and chlorine-containing compounds. For example, the sorbent 130 provided in the first series adsorption vessel 132 may be selective for adsorption of sulfur-containing compounds, the sorbent 130 provided in the second series adsorption vessel 132 may be selective for adsorption of nitrogen-containing compounds, the sorbent 130 provided in the third series adsorption vessel 132 may be selective for adsorption of oxygen-containing compounds, and the sorbent 130 provided in the fourth series adsorption vessel 132 may be selective for adsorption of chlorine-containing compounds. It will be appreciated that one adsorbent 130 selective with respect to more than one of the sulfur-containing, nitrogen-containing, oxygen-containing, and chlorine-containing compounds may be provided in one of the series adsorption vessels 132, thereby reducing the minimum total number of series adsorption vessels 132 required to adsorb the sulfur-containing, nitrogen-containing, oxygen-containing, and chlorine-containing compounds.

[0032] In one or more embodiments, a blend of adsorbents 130 may be provided in each series adsorption vessel 132 to achieve the desired adsorption characteristics of the sulfur-, nitrogen-, oxygen-, and chlorine-containing compounds. For example, the adsorbent 130 provided in the first series adsorption vessel 132 may be a blend selective for each of the sulfur-, nitrogen-, oxygen-, and chlorine-containing compounds, while the blend provided in the further series adsorption vessel 132 in series is directed to the intensive adsorption of only one of the sulfur-, nitrogen-, oxygen-, and chlorine-containing compounds. Furthermore, as described with respect to the embodiment having one adsorption vessel 122, a blend of multiple adsorbents 130 may be provided in each series adsorption vessel 132 in both a homogeneous manner as well as a heterogeneous manner.

[0033] In various embodiments in which the adsorption-based purification process 120 includes multiple adsorption vessels 122 in series, the total number of series adsorption vessels 132 may be two series adsorption vessels 132, three series adsorption vessels 132, four series adsorption vessels 132, five series adsorption vessels 132, up to eight series adsorption vessels 132, up to twelve series adsorption vessels 132, or two to twelve series adsorption vessels 132. Although an arrangement of three series adsorption vessels 132 is shown in Figure 3, it will be readily understood that Figure 3 may be reduced to two series adsorption vessels 132 or expanded to include twelve series adsorption vessels 132. It will be recognized that a greater number of series adsorption vessels 132 may increase the specificity in the selection of the adsorbent 130 placed within each series adsorption vessel 132 at the detriment of increased operating and capital costs.

[0034] Multiple adsorption vessels in parallel Referring to FIG. 4, in one or more embodiments, the adsorption-based purification process 120 includes multiple adsorption vessels 122, which may alternatively be referred to as parallel adsorption vessels 142. For clarity, the disclosure regarding the adsorption vessels 122 is fully transferable to the parallel adsorption vessels 142 as well. The liquid stream of the plastic pyrolysis oil 102 is in direct fluid communication with two or more parallel adsorption vessels 142, and the liquid stream of the plastic pyrolysis oil 102 is contacted with the adsorbent 130 contained therein to produce a treated plastic pyrolysis oil stream 108. In such a configuration, the adsorbent 130 collectively contained in each of the parallel adsorption vessels 142 is adapted to adsorb sulfur-containing compounds, nitrogen-containing compounds, oxygen-containing compounds, and chlorine-containing compounds. It will be appreciated, therefore, that in one or more embodiments, a single type of adsorbent 130 capable of adsorbing sulfur-containing compounds, nitrogen-containing compounds, oxygen-containing compounds, and chlorine-containing compounds is provided in each of the parallel adsorption vessels 142.

[0035] In one or more further embodiments, a plurality of different sorbents 130 are provided within each parallel adsorption vessel 142 to adsorb sulfur-containing, nitrogen-containing, oxygen-containing, and chlorine-containing compounds, with each sorbent 130 capable of adsorbing one or more of the sulfur-containing, nitrogen-containing, oxygen-containing, and chlorine-containing compounds. The plurality of different sorbents 130 may be provided in a homogeneous or heterogeneous manner. Specifically, in one or more embodiments, the plurality of different sorbents 130 are mixed together in an amalgam of sorbents 130, and in one or more further embodiments, the plurality of different sorbents 130 are provided as different layers or populations within each of the parallel adsorption vessels 142.

[0036] Providing the adsorption vessels 122 in a parallel configuration as parallel adsorption vessels 142 provides operational flexibility to the adsorption-based purification process 120. In one or more embodiments, each of the parallel adsorption vessels 142 includes a separate blend of adsorbents 130. Specifically, each of the parallel adsorption vessels 142 may include a blend of adsorbents 130 specific to the composition of the liquid stream of plastic pyrolysis oil 102 generated by the different compositions of the mixed plastics forming the inlet stream 101. Such an arrangement allows the liquid stream of plastic pyrolysis oil 102 to be provided to one of multiple parallel adsorption vessels 142 optimized to more effectively remove specific components. Targeted optimization for removal of specific components from the liquid stream of plastic pyrolysis oil 102 not only allows adaptation as the composition of the inlet stream 101 varies, but also allows the treated plastic pyrolysis oil stream 108 to be optimized to match the desired composition to be fed to a conventional purification process for further processing.

[0037] When the adsorption vessels 122 are provided in a parallel configuration, they can be operated in a rotational manner such that at least one of the parallel adsorption vessels 142 undergoes regeneration while at least one different parallel adsorption vessel 142 is operated to adsorb organic molecules containing one or more atoms of sulfur, nitrogen, oxygen, or chlorine from the liquid stream of plastic pyrolysis oil 102.

[0038] 5, in one or more embodiments, an adsorption-based purification process 120 is provided with a combination of parallel and series adsorption vessels 122. Specifically, the adsorption-based purification process 120 includes parallel adsorption paths, each of which is formed from multiple adsorption vessels 122 in series. Such a configuration provides the benefits of multiple parallel adsorption vessels 142, such as the ability to operate in a rotatable fashion, while also providing the benefits of multiple series adsorption vessels 132, such as tuning each adsorption vessel 122 for the adsorption of a specific type of component from the plastic pyrolysis oil 102 liquid stream.

[0039] In one or more embodiments, the adsorption vessel 122 , and by extension the series adsorption vessel 132 and the parallel adsorption vessel 142 , contain a fixed bed of adsorbent 130 .

[0040] In one or more embodiments, the adsorption vessel 122 , and by extension the series adsorption vessel 132 and the parallel adsorption vessel 142 , contain a slurry bed of adsorbent 130 .

[0041] In one or more embodiments, the adsorption vessel 122 , and by extension the series adsorption vessel 132 and the parallel adsorption vessel 142 , contain a moving bed of adsorbent 130 .

[0042] Adsorbent The sorbent 130 may be selected to remove undesirable organic molecules from the liquid stream of plastic pyrolysis oil 102. In one or more embodiments, the sorbent 130 provided in the adsorption vessel 122 is tailored to adsorb organic molecules that contain one or more atoms of sulfur, nitrogen, oxygen, or chlorine.

[0043] In various embodiments, the adsorbent 130 includes one or more of natural clays, such as attapulgus clay, alumina, silica gel, activated carbon, and natural and synthetic zeolites, such as ultra-stable zeolite Y. It is noted that each type of adsorbent 130 may improve the removal of one or more of sulfur or nitrogen or chlorine or oxygen.

[0044] 130-year-old 130-year-old household appliance ABW, ACO, AEI, AEL, AE N、AET、AFG、AFI、AFN、AFO、AFR、AFS、AFT、AFV、AFX、AFY、AHT、ANA、ANO、APC、 APD、AST、ASV、ATN、ATO、ATS、ATT、ATV、AVE、AVL、AWO、AWW、BCT、BEC、BIK、BO F、BOG、BOZ、BPH、BRE、BSV、CAN、CAS、CDO、CFI、CGF、CGS、CHA、-CHI、-CLO、CON CSV, CZP, DAC, DDR, DFO, DFT, DOH, DON, EAB, EDI, EEI, EMT, EON, EPI, ERI, E SV、ETL、ETR、ETV、EUO、EWO、EWS、EZT、FAR、FAU、FER、FRA、GIS、GIU、GME、GON、 GOO、HEU、IFO、IFR、-IFT、-IFU、IFW、IFY、IHW、IMF、IRN、IRR、-IRY、ISV、ITE 、ITG、ITH、ITR、ITT、-ITV、ITW、IWR、IWS、IWV、IWW、JBW、JNT、JOZ、JRY、JSN、J SR、JST、JSW、KFI、LAU、LEV、LIO、-LIT、LOS、LOV、LTA、LTF、LTJ、LTL、LTN、MA R、MAZ、MEI、MEL、MEP、MER、MFI、MFS、MON、MOR、MOZ、MRT、MSE、MSO、MTF、MTN、M TT、MTW、MVY、MWF、MWW、NAB、NAT、NES、NON、NPO、NPT、NSI、OBW、OFF、OKO、OSI 、OSO、OWE、-PAR、PAU、PCR、PHI、PON、POR、POS、PSI、PTO、PTT、PTY、PUN、PWN、P WO、PWW、RHO、-RON、RRO、RSN、RTE、RTH、RUT、RWR、RWY、SAF、SAO、SAS、SAT、SA V, SBE, SBN, SBS, SBT, SEW, SFE, SFF, SFG, SFH, SFN, SFO, SFS, SFW, SGT, SIV, S OD、SOF、SOR、SOS、SOV、SSF、SSY、STF、STI、STT、STW、-SVR、SVV、SWY、-SYT、S ZR、TER、THO、TOL、TON、TSC、TUN、UEI、UFI、UOS、UOV、UOZ、USI、UTL、UWY、VET、VFI, VNI, VSV, WEI, -WEN, YFI, YUG, ZON, * BEA, * CTH, * - EWT, * -ITN, * MRE, * PCS, * SFV, * -SSO, * STO, * -SVY, * For example, certain known zeolites used in the petroleum refining industry include, but are not limited to, mordenite, ZSM-5, ZSM-11, ZSM-12, ZSM-22, ZSM-23, ZSM 35, beta type ( *BEA), Y, USY, and MCM zeolites such as MCM-41 and MCM-48. For example, these include (FAU) framework structures including USY, which has a micropore size associated with a 12-membered ring when viewed along the

[0111] direction of 7.4×7.4 Å; (MFI) framework structures including ZSN-5, which has a micropore size associated with a 10-membered ring when viewed along the

[0100] and

[0010] directions of 5.5×5.1 Å and 5.6×5.3 Å, respectively; (MEL) framework structures including ZSM-11, which has a micropore size associated with a 10-membered ring when viewed along the

[0100] direction of 5.4×5.3 Å; (MTW) ​​framework structures including ZSM-12, which has a micropore size associated with a 12-membered ring when viewed along the

[0010] direction of 5.6×6.0 Å; and (TON) framework structures including ZSM-12, which has a micropore size associated with a 10-membered ring when viewed along the

[0001] direction of 4.6×5.7 Å. (MTT) framework structures including ZSM-23, having a micropore size associated with 10-membered rings when viewed along the <0001> direction of 4.5×5.2 Å; (FER) framework structures including ZSM-35, having micropore sizes associated with 10-membered rings and 8-membered rings when viewed along the <0001> and <0010> directions of 4.2×5.4 Å and 3.5×4.8 Å, respectively; (MOR) framework structures including mordenite zeolite, having micropore sizes associated with 12-membered rings and 8-membered rings when viewed along the <0001> and <0001> directions of 6.5×7.0 Å and 2.6×5.7 Å, respectively; and (C) framework structures including zeolite beta polymorph A, having micropore sizes associated with 12-membered rings when viewed along the <0100> and <0001> directions of 6.6×6.7 Å and 5.6×5.6 Å, respectively. * BEA) framework structures. Zeolite-type materials such as crystalline silicoaluminophosphate (SAPO) and aluminophosphate (AlPO) materials are also known.

[0045] In one or more embodiments, the sorbent 130 comprises activated carbon. It will be appreciated that the activated carbon can be easily disposed of, such as by burning at a power plant or by being gasified, without the need for disposal or regeneration of the solvent.

[0046] In one or more embodiments, the adsorbent 130 comprises ultra-stable zeolite Y. It will be appreciated that ultra-stable zeolite Y is commonly used for other purposes in the oil refining industry and is therefore readily available for use as the adsorbent 130. Additionally, spent ultra-stable zeolite Y from other catalytic conversion units within an oil refinery operation can be used as the adsorbent 130 after regeneration, providing both economic and environmental benefits through recycling within the oil refinery.

[0047] It is further noted that while embodiments of the sorbent 130 have been shown to include alumina or silica, the sorbent 130 may be a fresh or spent catalyst formed from silica, alumina, or a combination of both silica and alumina, in either a crystalline or amorphous state. The catalyst may additionally contain metals such as Co, Mo, Ni, or W.

[0048] In one or more embodiments, the sorbent 130 is provided as pellets, spheres, or extrudates. In further embodiments, the sorbent 130 is provided in a natural form. For purposes of this disclosure, a "natural form" is a geometric shape formed by crushing or breaking a larger mass of the sorbent 130. The sorbent 130 may be in pellets, spheres, extrudates, or natural forms having sizes ranging from 4 mesh to 60 mesh, 4 mesh to 50 mesh, 4 mesh to 40 mesh, or 4 mesh to 35 mesh in various embodiments. The adsorption rate of sorbents 130, such as activated carbon and zeolites, has been determined to be inversely dependent on particle size, making such parameters an important feature when analyzing the performance and suitability of the sorbent 130 for a particular application.

[0049] In one or more embodiments, the sorbent 130 may include a binder to aggregate the components of the sorbent 130 into a desired shape. Note that zeolites generally cannot bind together, so a binder component is used to form pellets or other desired shapes. In various embodiments, the binder may be alumina or silica-alumina.

[0050] In one or more embodiments, the adsorbent 130 has a solubility of at least 100 grams per square meter (m 2 / g). In various further embodiments, the adsorbent 130 has a surface area of ​​at least 125 m 2 / g, at least 200m 2 / g, at least 500m 2 / g, at least 1,000m 2 / g, or at least 2,000m 2 / g surface area.

[0051] In one or more embodiments, the adsorbent 130 has an average pore size of at least 10 Angstroms (Å). In various further embodiments, the adsorbent 130 has an average pore size of at least 25 Å, at least 50 Å, or at least 100 Å, as well as less than 800 Å, less than 500 Å, less than 400 Å, or less than 200 Å. The average pore size is calculated according to the Barrett-Joyner-Halenda (BJH) method. In one or more embodiments, the adsorbent 130 is mesoporous if the macropores are greater than 500 Å in diameter, the mesopores are 20 to 500 Å in diameter, and the micropores are less than 20 Å in diameter.

[0052] In one or more embodiments, the adsorbent 130 has a solubility of at least 100 grams per square meter (m 2 / g). In various further embodiments, the adsorbent 130 has a surface area of ​​at least 125 m 2 / g, at least 150m 2 / g, at least 200m 2 / g, or at least 250m 2 / g, up to 2,000m 2 / g, 1,800m 2 / g, 1,500m 2 / g, or 1,000m 2 / g surface area.

[0053] In one or more embodiments, the liquid stream of plastic pyrolysis oil 102 is contacted with the one or more adsorbents 130 in the adsorption vessel 122 at a temperature of 20 to 80° C. In various further embodiments, the liquid stream of plastic pyrolysis oil 102 is contacted with the one or more adsorbents 130 in the adsorption vessel 122 at a temperature of 20 to 80° C., 20 to 60° C., 20 to 50° C., or 20 to 40° C. It will be appreciated that operation at ambient conditions allows for operation without the need for external heating.

[0054] In one or more embodiments, the liquid stream of plastic pyrolysis oil 102 is contacted with the one or more adsorbents 130 in the adsorption vessel 122 at a pressure of 1 to 10 bar (0.1 to 1 MPa). In various further embodiments, the liquid stream of plastic pyrolysis oil 102 is contacted with the one or more adsorbents 130 in the adsorption vessel 122 at a pressure of 1 to 8 bar (0.1 to 0.8 MPa), 1 to 6 bar (0.1 to 0.6 MPa), 1 to 4 bar (0.1 to 0.4 MPa), or 1 to 3 bar (0.1 to 0.3 MPa).

[0055] In one or more embodiments, the liquid flow of the plastic pyrolysis oil 102 is maintained at a temperature between 0.1 and 8 inverse hours (h -1 In various further embodiments, the liquid stream of plastic pyrolysis oil 102 is contacted with the one or more adsorbents 130 in the adsorption vessel 122 at a liquid hourly space velocity (LHSV) of 0.1 to 5 h -1 , 0.1 to 4h -1 , or 0.1 to 3h -1 The adsorbent is contacted with the one or more adsorbents 130 in the adsorption vessel 122 at an LHSV of 100 to 200 MPa. It will be appreciated that the LHSV may be affected by the size of the adsorption vessel 122, with smaller adsorption vessels 122 having a relatively higher LHSV than larger adsorption vessels 122.

[0056] Adsorbent particles such as the adsorbent 130 have a finite capacity for liquid phase molecules. Extended contact with the liquid stream of plastic pyrolysis oil 102 will eventually result in a thermodynamic equilibrium between the solid phase of the adsorbent 130 and the organic molecules desired to be removed. In this equilibrium condition, the rates of adsorption and desorption are equal, the net loading on the adsorbent 130 cannot be increased, and the adsorbent 130 must either be regenerated or simply replaced. In one or more embodiments, the adsorbent is discarded from the adsorption vessel 122, and by extension from the series adsorbent vessel 132 and the parallel adsorbent vessel 142. Additionally, in one or more embodiments, the adsorbent 130 in the adsorption vessel 122, and by extension the adsorbent 130 in the series adsorbent vessel 132 and the parallel adsorbent vessel 142, may be regenerated to strip off the adsorbed organic molecules and reset the equilibrium. Any suitable regeneration method known to one of skill in the art may be practiced in accordance with the present disclosure.

[0057] Exemplary methods of desorption and regeneration include one or, more commonly, a combination of the following: increasing temperature, reducing partial pressure, reducing concentration, purging with an inert fluid, replacement with a more strongly adsorbing species, a polar solvent to desorb the adsorbed species, or changing chemical conditions such as pH. The method may be selected based on the particular adsorbent 130 placed within the adsorption vessel 122. When a polar solvent is utilized to desorb the adsorbed species, such a solvent may, in one or more embodiments, have a Hildebrand solubility parameter of at least 18 MPa.

[0058] Treated plastic pyrolysis oil As previously indicated, it is desirable to remove organic molecules containing one or more atoms of sulfur, nitrogen, oxygen, or chlorine from the plastic pyrolysis oil 102 liquid stream before feeding the resulting treated plastic pyrolysis oil stream 108 to a conventional refining process for the production of value-added products, as such organic molecules can interfere with or affect the chemical reactions that occur in conventional refining processes.

[0059] In one or more embodiments, the treated plastic pyrolysis oil stream 108 may contain up to 10 ppmw sulfur. In various further embodiments, the treated plastic pyrolysis oil stream 108 may contain up to 8 ppmw sulfur, up to 6 ppmw sulfur, up to 3 ppmw sulfur, or up to 1 ppmw sulfur.

[0060] In one or more embodiments, the treated plastic pyrolysis oil stream 108 may contain up to 10 ppmw nitrogen. In various further embodiments, the treated plastic pyrolysis oil stream 108 may contain up to 8 ppmw nitrogen, up to 6 ppmw nitrogen, up to 3 ppmw nitrogen, or up to 1 ppmw nitrogen.

[0061] In one or more embodiments, the treated plastic pyrolysis oil stream 108 may contain up to 10 ppmw chlorine. In various further embodiments, the treated plastic pyrolysis oil stream 108 may contain up to 8 ppmw chlorine, up to 6 ppmw chlorine, up to 3 ppmw chlorine, or up to 1 ppmw chlorine.

[0062] In one or more embodiments, the treated plastic pyrolysis oil stream 108 may contain up to 10 ppmw oxygen. In various further embodiments, the treated plastic pyrolysis oil stream 108 may contain up to 8 ppmw oxygen, up to 6 ppmw oxygen, up to 3 ppmw oxygen, or up to 1 ppmw oxygen.

[0063] In one or more embodiments, the process for converting waste plastics into refinery feedstocks may be integrated with conventional refining, which for purposes of this disclosure refers to existing refinery operations for processing crude oil into multiple useful products. EXAMPLES

[0064] The following examples illustrate features of the present disclosure but are not intended to limit the scope of the disclosure.

[0065] Representative tests were conducted to demonstrate the utility of the process for converting waste plastics into refinery feedstocks according to the present disclosure. Specifically, plastic pyrolysis oil was produced and then treated to remove organic molecules containing one or more atoms of sulfur, nitrogen, oxygen, or chlorine as disclosed in the present disclosure.

[0066] Production of plastic pyrolysis oil A plastic feed comprising a mixture of HDPE, LDPE, PP, LLDPE, PS, and PET was fed to a plastic pyrolysis unit 110 and processed to produce a stream of plastic pyrolysis oil 102. Further outputs from the plastic pyrolysis unit 110 were gaseous products including C1, C2, C3, C4 paraffinic and olefinic hydrocarbons, as well as other contaminant gases, and various solids. The nature and composition of the plastic pyrolysis oil 102 is shown in Table 2. Further, the plastic pyrolysis oil 102 was fed to a first fractionator 152 in accordance with the present disclosure and separated into a distillation fraction 103 comprising naphtha and diesel boiling in the range of 36 to 370° C. and a vacuum gas oil fraction 104 comprising hydrocarbons boiling above 370° C. The breakdown of the naphtha, diesel, and vacuum gas oil is also given in Table 2.

[0067] [Table 2]

[0068] Example 1 of the present invention An exemplary plastic pyrolysis oil having the composition outlined in Table 2 was treated with an adsorbent in an adsorption vessel in accordance with the present disclosure. Specifically, 50 grams of the exemplary plastic pyrolysis oil was passed through an adsorption column containing 20 grams of activated carbon at a temperature of 20° C. and atmospheric pressure. The activated carbon utilized was 770 ml 2 / g surface area, 12.7 Å average pore diameter, and 0.442 cm 3The treated plastic pyrolysis oil discharged as effluent from the adsorption column packed with activated carbon was collected and analyzed for the presence of nitrogen, sulfur, and chlorine. It is noted that 48 grams of treated plastic pyrolysis oil was collected. The reductions of nitrogen, sulfur, and chlorine are shown in Table 3. A simulated distillation profile of the treated plastic pyrolysis oil produced by adsorption in a column of activated carbon was also prepared, as shown in Table 4.

[0069] [Table 3]

[0070] [Table 4]

[0071] A review of Table 3 shows that treating the exemplary plastic pyrolysis oil with activated carbon according to the process of the present disclosure reduced nitrogen, sulfur, and chlorine in the treated plastic pyrolysis oil. Specifically, the treated plastic pyrolysis oil of the present invention Example 1 had an 89 percent reduction in nitrogen, a 61 percent reduction in sulfur, and a 52.3 percent reduction in chlorine. With further reference to Table 4, it is noted that the boiling point characteristics of the treated plastic pyrolysis oil of the present invention Example 1 compared to the original exemplary plastic pyrolysis oil did not change substantially.

[0072] Example 2 of the present invention An exemplary plastic pyrolysis oil having the composition outlined in Table 2 was also treated with USY zeolite functioning as an adsorbent in an adsorption vessel in accordance with the present disclosure. Specifically, 50 grams of the exemplary plastic pyrolysis oil was passed through an adsorption column containing 20 grams of USY zeolite at a temperature of 20° C. and atmospheric pressure. A zeolite-based adsorbent was used. The adsorbent contained 35% by weight USY zeolite, the remainder being an alumina binder. The USY zeolite was 280 ml 2 / g surface area, and 0.19 cm 3The treated plastic pyrolysis oil discharged as effluent from the adsorption column packed with USY zeolite was collected and analyzed for the presence of nitrogen, sulfur, and chlorine. It is noted that 47 grams of treated plastic pyrolysis oil was collected. The reductions in nitrogen, sulfur, and chlorine are shown in Table 5. A simulated distillation profile of the treated plastic pyrolysis oil produced by adsorption in a column of USY zeolite was also prepared, as shown in Table 6.

[0073] [Table 5]

[0074] [Table 6]

[0075] A review of Table 5 shows that treating the exemplary plastic pyrolysis oil with USY zeolite according to the process of the present disclosure reduced the nitrogen in the treated plastic pyrolysis oil. Specifically, the treated plastic pyrolysis oil of inventive Example 2 had an 87 percent reduction in nitrogen. With further reference to Table 6, it is noted that the boiling point characteristics of the treated plastic pyrolysis oil of inventive Example 2 did not change substantially compared to the initial exemplary plastic pyrolysis oil.

[0076] Various aspects of processes and associated systems for converting waste plastics into refinery feedstocks have been described herein, and it should be understood that such aspects may be utilized in conjunction with various other aspects.

[0077] According to a first aspect, a process for converting waste plastics into refinery feedstock comprises the steps of: (a) pyrolysis of a plastic feedstock comprising waste plastics to produce a liquid stream of plastic pyrolysis oil, a tail gas stream, and a solid stream; (b) feeding the liquid stream of plastic pyrolysis oil directly to an adsorption-based refining process to produce a treated plastic pyrolysis oil stream having less than 10 ppmw nitrogen, less than 10 ppmw sulfur, less than 10 ppmw chlorine, and less than 10 ppmw oxygen, the adsorption-based refining process comprising: i) feeding the liquid stream of plastic pyrolysis oil directly to an adsorption vessel; wherein the adsorbent is adapted to adsorb organic molecules containing one or more atoms of sulfur, nitrogen, oxygen, or chlorine, wherein at least one of the one or more adsorbents is adapted to adsorb organic molecules containing each of sulfur, nitrogen, oxygen, and chlorine; ii) discharging the treated plastic pyrolysis oil stream from the adsorption vessel; and (c) collecting the treated plastic pyrolysis oil stream from the adsorption vessel for further processing into value-added products as feedstock for conventional refining processes.

[0078] A second embodiment includes the process of the first embodiment, wherein the pyrolysis of the plastic feedstock is carried out at a temperature of from 300° C. to 1000° C. in the presence of a catalyst.

[0079] A third embodiment includes the process of the first or second embodiment, wherein the plastic feedstock comprises one or more polymers selected from polyethylene terephthalate (PET), high density polyethylene (HDPE), polyvinyl chloride (PVC), polypropylene (PP), polystyrene (PS), and low density polyethylene (LDPE).

[0080] A fourth aspect includes the process of any of the first to third aspects, wherein the plastic feedstock comprises mixed plastics of differing composition.

[0081] A fifth aspect includes the process of any of the first to fourth aspects, wherein the adsorbent is selected from the group consisting of natural clay, alumina, silica gel, activated carbon, natural zeolites, synthetic zeolites, alumina, silica, or a combination of alumina and silica, in an amorphous or crystalline state.

[0082] A sixth embodiment includes the process of any of the first to fourth embodiments, wherein the adsorbent comprises activated carbon.

[0083] A seventh embodiment includes the process of any of the first to sixth embodiments, wherein the adsorption vessel comprises a fixed bed of adsorbent.

[0084] An eighth embodiment includes the process of any of the first to sixth embodiments, wherein the adsorption vessel comprises a slurry bed of adsorbent.

[0085] A ninth embodiment includes the process of any of the first to sixth embodiments, wherein the adsorption vessel comprises a moving bed of adsorbent.

[0086] A tenth embodiment includes the process of any of the first to ninth embodiments, wherein the adsorbent is provided as pellets, spheres, extrudates, or natural shapes having a size ranging from 4 mesh to 60 mesh.

[0087] An eleventh aspect includes the process of any of the first to tenth aspects, wherein the adsorption-based purification process includes two or more adsorption vessels.

[0088] A twelfth embodiment includes the process of the eleventh embodiment, wherein the adsorption vessels are arranged in series.

[0089] A thirteenth embodiment includes the process of the eleventh embodiment, wherein the adsorption vessels are arranged in parallel.

[0090] A fourteenth embodiment includes the process of the thirteenth embodiment, wherein the adsorption vessels are operated in an alternating manner such that while at least one adsorption vessel is undergoing regeneration, at least one different adsorption vessel is operating to adsorb organic molecules comprising one or more atoms of sulfur, nitrogen, oxygen, or chlorine from the plastic pyrolysis oil liquid stream.

[0091] A fifteenth embodiment includes the process of the eleventh embodiment, wherein the adsorption vessels are arranged as parallel adsorption paths of the adsorption vessels arranged in series.

[0092] A sixteenth embodiment includes the process of the fifteenth embodiment, wherein the parallel adsorption paths are operated in an alternating manner such that while at least one of the parallel adsorption paths is undergoing regeneration, at least one different parallel adsorption path is operating to adsorb organic molecules comprising one or more atoms of sulfur, nitrogen, oxygen, or chlorine from the plastic pyrolysis oil liquid stream.

[0093] A seventeenth embodiment includes the process of any of the eleventh to sixteenth embodiments, wherein the same adsorbent is placed in each of the adsorption vessels.

[0094] An eighteenth embodiment includes the process of any of the eleventh to sixteenth embodiments, wherein at least two of the adsorption vessels contain adsorbents of different composition.

[0095] In a nineteenth embodiment, the adsorbent is at least 100 m 2 / g surface area, an average pore size of at least 10 Å, and a mean pore size of at least 0.1 cm 3 The process of any of the first to eighteenth aspects, wherein the pore volume is 0.1 to 0.5 µm / g.

[0096] A twentieth embodiment provides a method for preparing a liquid stream of plastic pyrolysis oil at a temperature of 20 to 80° C., a pressure of 1 to 10 bar (0.1 to 1 MPa), and a thermal decomposition temperature of 0.1 to 1 h. -1 20. The process of any of the first to 19th aspects, wherein the adsorbent is contacted with the one or more adsorbents in the adsorption vessel at a liquid hourly space velocity of

[0097] A twenty-first embodiment includes the process of any of the first through twentieth embodiments, wherein the plastic pyrolysis oil liquid stream comprises up to 2000 ppmw sulfur, up to 5000 ppmw nitrogen, up to 2000 ppmw chlorine, and up to 2000 ppmw oxygen.

[0098] A twenty-second embodiment includes the process of any of the first to twenty-first embodiments, wherein the treated plastic pyrolysis oil stream comprises less than 1 ppmw nitrogen, less than 1 ppmw sulfur, less than 1 ppmw chlorine, and less than 1 ppmw oxygen.

[0099] It should be apparent to one skilled in the art that various modifications and variations can be made to the described embodiments without departing from the spirit and scope of the claimed subject matter. Therefore, it is intended that this specification cover modifications and variations of the various described embodiments, provided such modifications and variations come within the scope of the appended claims and their equivalents.

[0100] Nouns include plural referents unless the context clearly requires otherwise.

[0101] Throughout this disclosure, ranges are given. Each discrete value encompassed by the range is considered to be inclusive. In addition, ranges that may be formed by each discrete value encompassed by an explicitly disclosed range are considered to be inclusive as well. For the sake of brevity, the same is not explicitly stated after each disclosed range, but the present general indication is given.

[0102] As used in this disclosure and the appended claims, the words "comprise," "has," and "include," as well as all grammatical variations thereof, are each intended to have an open, non-limiting meaning that does not exclude additional elements or steps. [Explanation of symbols]

[0103] 101 Inlet flow 102 Plastic pyrolysis oil 104 Exhaust gas flow 106 Solid flow 108 Treated plastic pyrolysis oil stream 110 Plastic pyrolysis unit 120 Adsorption-Based Purification Processes 122 Adsorption container 130 Adsorbents 132 Series adsorption vessel 142 Parallel adsorption vessel 208 Intermediately processed plastic pyrolysis oil stream

Claims

1. In the process of converting waste plastic into refined raw materials, (a) conducting pyrolysis of a plastic feedstock, including waste plastic, to produce a liquid stream of plastic pyrolysis oil, a tail gas stream, and a solid stream; (b) feeding the plastic pyrolysis oil liquid stream directly to an adsorption-based refinery process to produce a treated plastic pyrolysis oil stream containing less than 10 ppmw nitrogen, less than 10 ppmw sulfur, less than 10 ppmw chlorine, and less than 10 ppmw oxygen, said adsorption-based refinery process comprising: i) contacting the plastic pyrolysis oil liquid stream with one or more adsorbents in an adsorption vessel, the adsorbents being adapted to adsorb organic molecules containing one or more atoms of sulfur, nitrogen, oxygen, or chlorine, at least one of the one or more adsorbents being adapted to adsorb organic molecules containing each of sulfur, nitrogen, oxygen, and chlorine; ii) discharging the treated plastic pyrolysis oil stream from the adsorption vessel; and (c) collecting the treated plastic pyrolysis oil stream from the adsorption vessel for further processing into value-added products as feedstock for conventional refining processes; The process comprising:

2. 2. The process of claim 1, wherein the plastic feedstock comprises one or more polymers selected from polyethylene terephthalate (PET), high density polyethylene (HDPE), polyvinyl chloride (PVC), polypropylene (PP), polystyrene (PS), and low density polyethylene (LDPE).

3. 3. The process of claim 1 or 2, wherein the adsorbent is selected from the group consisting of natural clay, alumina, silica gel, activated carbon, natural zeolites, synthetic zeolites, silica, or a combination of alumina and silica, in an amorphous or crystalline state.

4. 4. The process of claim 1, wherein the adsorbent comprises activated carbon.

5. 5. The process of claim 1 , wherein the adsorption vessel comprises a fixed bed of the adsorbent.

6. 5. The process of claim 1, wherein the adsorption vessel comprises a slurry bed of adsorbent.

7. 5. The process of claim 1, wherein the adsorption vessel comprises a moving bed of adsorbent.

8. 8. The process of any one of claims 1 to 7, wherein the adsorbent is provided as pellets, spheres, extrudates, or natural shapes having a size ranging from 4 mesh to 60 mesh.

9. 9. The process of claim 1 , wherein the adsorption-based purification process comprises two or more adsorption vessels.

10. 10. The process of claim 9, wherein the adsorption vessels are arranged in series.

11. 10. The process of claim 9, wherein the adsorption vessels are provided in parallel and operated in an alternating fashion such that while at least one adsorption vessel is undergoing regeneration, at least one different adsorption vessel is operating to adsorb the organic molecules comprising one or more atoms of sulfur, nitrogen, oxygen, or chlorine from the plastic pyrolysis oil liquid stream.

12. 12. The process of any one of claims 9 to 11, wherein the same adsorbent is contained in each of the adsorption vessels.

13. 12. The process of any one of claims 9 to 11, wherein at least two of the adsorption vessels contain adsorbents of different composition.

14. The adsorbent is at least 100 m ２ / g surface area, an average pore size of at least 10 Å, and at least 0.1 cm ３ The process of claim 1 having a total pore volume of about 1 / g.

15. The liquid stream of plastic pyrolysis oil is heated at a temperature of 20 to 80° C., at a pressure of 1 to 10 bar (0.1 to 1 MPa), and for 0.1 to 1 h. －１ 15. The process of claim 1, wherein the adsorbent is contacted with the one or more adsorbents in the adsorption vessel at a liquid hourly space velocity of at least about 1000 psi.

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