System and method for processing pyrolysis oil at elevated temperatures

Abstract

Provided here are systems and methods for processing pyrolysis oil to remove heteroatom-containing species. A method presented herein includes the step of pretreating pyrolysis oil to yield pretreated pyrolysis oil, the pretreating including decreasing an amount of a first set of chloride-containing species in the pyrolysis oil via a gas stripping operation at elevated temperatures. The method includes the step of performing a hydroprocessing operation on the pretreated pyrolysis oil to yield hydroprocessed pyrolysis oil. The elevated temperatures may include a liquid temperature from about 120 degrees Celsius (°C) to about 250 °C and / or a vapor temperature from about 30 °C to about 100 °C. The gas stripping operation may include providing a gas stream into the pyrolysis oil in which the gas stream contains steam, nitrogen, or carbon dioxide, or a combination thereof.

Description

SYSTEM AND METHOD FOR PROCESSING PYROLYSIS OIL AT ELEVATED TEMPERATURESTECHNICAL FIELD

[0001] The present disclosure generally relates to systems and methods of processing pyrolysis oil. More specifically, the present disclosure relates to systems and methods for pretreating pyrolysis oil using at least a gas stripping operation at elevated temperatures prior to hydrotreatment.BACKGROUND

[0002] Pyrolysis oil originates from the chemical recycling of mixed plastic waste (MPW). For example, pyrolysis oil can be formed by pyrolyzing MPW at sufficiently elevated temperatures (e.g., between 400 °C and 500 °C) under anaerobic conditions. Pyrolysis oil predominantly contains small hydrocarbon molecules that can include a number of different heteroatoms, such as oxygen, nitrogen, and halide (e.g., chloride, bromide, fluoride) atoms, depending on the composition of the MPW and the pyrolysis process. It is presently recognized that the heteroatom content of pyrolysis oil can lead to undesirable gum formation within the pyrolysis oil. Additionally, it is presently recognized that the heteroatom content of the pyrolysis oil can cause corrosion and / or fouling issues with various processing equipment, such as hydrotreatment units and / or cracking units. As such, there remains a need to develop improved techniques to decrease the heteroatom content in pyrolysis oil.SUMMARY

[0003] Examples set forth herein include systems and methods for processing pyrolysis oil to remove heteroatom-containing species from the pyrolysis oil prior to hydrotreatment and steam cracking. One such method includes the step of pretreating pyrolysis oil to yield pretreated pyrolysis oil, the pretreating including decreasing an amount of a first set of chloride-containing species in the pyrolysis oil via a gas stripping operation at elevated temperatures. The method includes the step of performing a hydroprocessing operation on the pretreated pyrolysis oil to yield hydroprocessed pyrolysis oil. In some embodiments, the method includes the step of pyrolyzing mixed plastic waste to yield the pyrolysis oil. In some embodiments, the first set of chloride- containing species substantially contains chloroalkanes. In some embodiments, the first set ofchloride-containing species includes chloroethane, 2-chloroethanol, 1,2-di chloroethane, 1-chloro- 2-propanol, 2-chloro-ethanol acetate, or chloroethylbenzene, or any combination thereof. In some embodiments, the elevated temperatures include a liquid temperature from about 120 degrees Celsius (°C) to about 250 °C, a vapor temperature from about 30 °C to about 100 °C, or a combination thereof. In some embodiments, the gas stripping operation includes the step of providing a gas stream into the pyrolysis oil to decrease the amount of the first set of chloride- containing species in the pyrolysis oil, in which the gas stream comprises steam, nitrogen (N2), or carbon dioxide (CO2), or a combination thereof.

[0004] In some embodiments, pretreating the pyrolysis oil comprises includes the step of decreasing an amount of a second set of chloride-containing species, or a first set of nitrogencontaining species, or a combination thereof, in the pyrolysis oil via a solvent extraction operation using a polar solvent, in which the polar solvent includes dimethylsulfoxide (DMSO), N- methylpyrrolidone (NMP), dimethylformamide (DMF), ethylene glycol, water, or a combination thereof, and in which the second set of chloride-containing species includes chloroethers, chloroalcohols, or chloroesters, or a combination thereof. In some embodiments, pretreating the pyrolysis oil comprises includes the step of decreasing an amount of a third set of chloride- containing species, a second set of nitrogen-containing species, or a first set of oxygen-containing species, or a combination thereof, in the pyrolysis oil via an adsorption operation using one or more adsorbents, in which the one or more adsorbents comprise silica gel, zeolites, activated carbon, alumina, clays, solid acids, solid bases, or ion-exchange resins, or a combination thereof. In some embodiments, the pretreated pyrolysis oil includes less than 0.02 weight percent (wt. %) gum impurities after 30 days. In some embodiments, the method includes the steps of dissolving the hydroprocessed pyrolysis oil in naphtha, in which a weight ratio of hydroprocessed pyrolysis oil to naphtha is greater than 0.5, and steam cracking the hydroprocessed pyrolysis oil to yield a plurality of hydrocarbon products.

[0005] One such system includes a pyrolysis oil processing system having a gas stripping unit, in which the gas stripping unit is configured to contact a pyrolysis oil with one or more stripping gases at elevated temperatures to extract a portion of a first set of chloride-containing impurities from the pyrolysis oil, yielding a gas stream that contains the portion of the chloride-containing impurities and yielding a liquid stream that contains pretreated pyrolysis oil. The system includes a hydroprocessing unit disposed downstream of the gas stripping unit and configured to receiveand hydroprocess the pretreated pyrolysis oil to yield hydroprocessed pyrolysis oil. In some embodiments, the one or more stripping gases contain steam, N2, or CO2, or a combination thereof, and the one or more stripping gases are free of hydrogen (H2), and the elevated temperatures include a liquid temperature from about 120 degrees Celsius (°C) to about 250 °C, a vapor temperature from about 30 °C to about 100 °C, or a combination thereof, and the gas stripping unit is configured to extract at least 70% of the first set of chloride-containing impurities from the pyrolysis oil, the first set of chloride-containing impurities including chloroethane, 2- chloroethanol, 1,2-di chloroethane, l-chloro-2-propanol, 2-chloro-ethanol acetate, or chloroethyl benzene, or any combination thereof.

[0006] In some embodiments, the system includes a liquid extraction unit disposed downstream of the gas stripping unit and upstream of the hydroprocessing unit, in which the liquid extraction unit is configured to contact the pretreated pyrolysis oil of the liquid stream with a polar solvent to extract a second set of chloride-containing impurities, or nitrogen-containing impurities, or a combination thereof, from the pretreated pyrolysis oil, and in which the second set of chloride- containing impurities comprises chloroethers, chloroalcohols, or chloroesters, or a combination thereof. In some embodiments, the system includes an adsorption unit disposed downstream of the gas stripping unit and upstream of the hydroprocessing unit, in which the adsorption unit is configured to contact the pretreated pyrolysis oil with one or more adsorbents to extract nitrogencontaining impurities, oxygen-containing impurities, or a third set of chloride-containing impurities, or a combination thereof, from the pretreated pyrolysis oil. In some embodiments, the system includes a steam cracking unit disposed downstream of the hydroprocessing unit and configured to receive and crack the hydroprocessed pyrolysis oil without naphtha dilution.

[0007] Aspects and advantages of these exemplary examples and other examples, are discussed in detail herein. Moreover, it is to be understood that both the foregoing information and the following detailed description provide merely illustrative examples of various aspects and examples, and are intended to provide an overview or framework for understanding the nature and character of the claimed aspects and examples. Accordingly, these and other objects, along with advantages and features of the present disclosure, will become apparent through reference to the following description and the accompanying drawings. Furthermore, it is to be understood that the features of the various examples described herein are not mutually exclusive and may exist in various combinations and permutations.BRIEF DESCRIPTION OF THE DRAWINGS

[0008] The accompanying drawings, which are included to provide a further understanding of the examples of the present disclosure, are incorporated in and constitute a part of this specification, illustrate examples of the present disclosure, and together with the detailed description, serve to explain principles of the examples discussed herein. No attempt is made to show structural details of this disclosure in more detail than may be necessary for a fundamental understanding of the examples discussed herein and the various ways in which they may be practiced. According to common practice, the various features of the drawings discussed below are not necessarily drawn to scale. Dimensions of various features and elements in the drawings may be expanded or reduced to more clearly illustrate examples of the disclosure.

[0009] FIG. 1 is a diagrammatic representation of an embodiment of a hydrocarbon processing system for processing of pyrolysis oil, according to an example.

[0010] FIG. 2 is a diagrammatic representation of an embodiment of a method for pretreating pyrolysis oil to yield pretreated pyrolysis oil, and for hydrotreating the pretreated pyrolysis oil to yield hydrotreated pyrolysis oil, according to an example.

[0011] FIG. 3 is a diagrammatic representation of an embodiment of a gas stripping subzone for performing the gas stripping operation during the pretreatment of pyrolysis oil to yield gas-stripped pyrolysis oil, according to an example.

[0012] FIG. 4 is a diagrammatic representation of an embodiment of a method in which a controller controls operation of the embodiment of the gas stripping subzone illustrated in FIG. 3, according to an example.

[0013] FIG. 5 is a diagrammatic representation of an embodiment of a solvent extraction subzone for performing the solvent extraction operation during the pretreatment of pyrolysis oil to yield solvent-extracted pyrolysis oil, according to an example.

[0014] FIG. 6 is a diagrammatic representation of an embodiment of an adsorption subzone for performing the adsorption treatment operation during the pretreatment of pyrolysis oil to yield adsorbent-treated pyrolysis oil, according to an example.DETAILED DESCRIPTION

[0015] The present disclosure describes various examples related to systems and methods for processing pyrolysis oil to remove heteroatom-containing species from the pyrolysis oil prior tohydrotreatment and steam cracking. The description may use the phrases “in certain examples,” “in various examples,” “in an example,” or “in examples,” which may each refer to one or more of the same or different examples. Furthermore, the terms “comprising,” “including,” “having,” and the like, as used with respect to examples of the present disclosure, are synonymous. The term “plurality” as used herein refers to two or more items or components. The terms “about” or “approximately” are defined as being close to as understood by one of ordinary skill in the art. In one non-limiting example, these terms are defined to be within 10%, preferably within 5%, more preferably within 1%, and most preferably within 0.5%.

[0016] The terms “removing,” “removed,” “reducing,” “reduced,” or any variation thereof, when used in the claims and / or the specification includes any measurable decrease of one or more components in a mixture to achieve a desired result. The use of the words “a” or “an” when used in conjunction with any of the terms “comprising,” “including,” “containing,” or “having,” in the claims or the specification may mean “one,” but it is also consistent with the meaning of “one or more,” “at least one,” and “one or more than one.” The terms “wt. %”, “vol. %”, or “mol. %” refers to a weight, volume, or molar percentage of a component, respectively, based on the total weight, the total volume of material, or total moles, which includes the component. In a nonlimiting example, 10 grams of a component in 100 grams of the material is 10 wt. % of the component.

[0047] As used herein, the term “Cx-y compounds,” in which x and y are positive integer values, refers to hydrocarbon-based compounds, each compound containing between x and y carbon atoms, x and y inclusive. For example, a C3-5 stream refers to a mixture that substantially contains or entirely contains hydrocarbon-based compounds, each compound containing 3, 4, or 5 carbon atoms. The term “substantially contains” means that the mixture includes at least 50 mol. % of the named compound or class of compounds, such as at least 60 mol. %, at least 70 mol. %, at least 80 mol. %, at least 90 mol. %, at least 95 mol. %, at least 98 mol. %, at least 99 mol. %, or 100 mol. %, or any sub-ranges therebetween. As used herein, the term “zone” can refer to an area including one or more units and / or one or more subzones. Units can include one or more reactors or reactor vessels, separators, strippers, extraction columns, fractionation columns, heaters, exchangers, pipes, pumps, valves, compressors, sensors, and controllers. Additionally, a unit, such as a reactor, dryer, or vessel, can further include one or more zones or subzones that contain various equipment.

[0017] Examples set forth herein include systems and methods for processing pyrolysis oil to remove a substantial portion of one or more heteroatom-containing species from the pyrolysis oil prior to hydrotreatment and steam cracking. One such method includes the steps of pretreating pyrolysis oil to yield pretreated pyrolysis oil, the pretreating including decreasing an amount of a first set of chloride-containing species in the pyrolysis oil via a gas stripping operation at elevated temperatures. The method includes the step of performing a hydroprocessing operation on the pretreated pyrolysis oil to yield hydroprocessed pyrolysis oil. In some embodiments, the method includes the step of pyrolyzing mixed plastic waste to yield the pyrolysis oil. In some embodiments, the first set of chloride-containing species substantially contains chloroalkanes. In some embodiments, the first set of chloride-containing species includes chloroethane, 2- chloroethanol, 1,2-di chloroethane, l-chloro-2-propanol, 2-chloro-ethanol acetate, or chloroethylbenzene, or any combination thereof. In some embodiments, the elevated temperatures include a liquid temperature from about 120 degrees Celsius (°C) to about 250 °C, a vapor temperature from about 30 °C to about 100 °C, or a combination thereof. In some embodiments, the gas stripping operation includes the step of providing a gas stream into the pyrolysis oil to decrease the amount of the first set of chloride-containing species in the pyrolysis oil, in which the gas stream comprises steam, nitrogen (N2), or carbon dioxide (CO2), or a combination thereof.

[0018] In some embodiments, pretreating the pyrolysis oil comprises includes the step of decreasing an amount of a second set of chloride-containing species, or a first set of nitrogencontaining species, or a combination thereof, in the pyrolysis oil via a solvent extraction operation using a polar solvent, in which the polar solvent includes dimethylsulfoxide (DMSO), N- methylpyrrolidone (NMP), dimethylformamide (DMF), ethylene glycol, water, or a combination thereof, and in which the second set of chloride-containing species includes chloroethers, chloroalcohols, or chloroesters, or a combination thereof. In some embodiments, pretreating the pyrolysis oil comprises includes the step of decreasing an amount of a third set of chloride- containing species, a second set of nitrogen-containing species, or a first set of oxygen-containing species, or a combination thereof, in the pyrolysis oil via an adsorption operation using one or more adsorbents, in which the one or more adsorbents comprise silica gel, zeolites, activated carbon, alumina, clays, solid acids, solid bases, or ion-exchange resins, or a combination thereof. In some embodiments, the pretreated pyrolysis oil includes less than 0.02 weight percent (wt. %) gum impurities after 30 days. In some embodiments, the method includes the steps of dissolvingthe hydroprocessed pyrolysis oil in naphtha, in which a weight ratio of hydroprocessed pyrolysis oil to naphtha is greater than 0.5, and steam cracking the hydroprocessed pyrolysis oil to yield a plurality of hydrocarbon products.

[0019] One such system includes a pyrolysis oil processing system having a gas stripping unit, in which the gas stripping unit is configured to contact a pyrolysis oil with one or more stripping gases at elevated temperatures to extract a portion of a first set of chloride-containing impurities from the pyrolysis oil, yielding a gas stream that contains the portion of the chloride-containing impurities and yielding a liquid stream that contains pretreated pyrolysis oil. The system includes a hydroprocessing unit disposed downstream of the gas stripping unit and configured to receive and hydroprocess the pretreated pyrolysis oil to yield hydroprocessed pyrolysis oil. In some embodiments, the one or more stripping gases contain steam, N2, or CO2, or a combination thereof, and the one or more stripping gases are free of hydrogen (H2), and the elevated temperatures include a liquid temperature from about 120 degrees Celsius (°C) to about 250 °C, a vapor temperature from about 30 °C to about 100 °C, or a combination thereof, and the gas stripping unit is configured to extract at least 70% of the first set of chloride-containing impurities from the pyrolysis oil, the first set of chloride-containing impurities including chloroethane, 2- chloroethanol, 1,2-di chloroethane, l-chloro-2-propanol, 2-chloro-ethanol acetate, or chloroethyl benzene, or any combination thereof.

[0020] In some embodiments, the system includes a liquid extraction unit disposed downstream of the gas stripping unit and upstream of the hydroprocessing unit, in which the liquid extraction unit is configured to contact the pretreated pyrolysis oil of the liquid stream with a polar solvent to extract a second set of chloride-containing impurities, or nitrogen-containing impurities, or a combination thereof, from the pretreated pyrolysis oil, and in which the second set of chloride- containing impurities comprises chloroethers, chloroalcohols, or chloroesters, or a combination thereof. In some embodiments, the system includes an adsorption unit disposed downstream of the gas stripping unit and upstream of the hydroprocessing unit, in which the adsorption unit is configured to contact the pretreated pyrolysis oil with one or more adsorbents to extract nitrogencontaining impurities, oxygen-containing impurities, or a third set of chloride-containing impurities, or a combination thereof, from the pretreated pyrolysis oil. In some embodiments, the system includes a steam cracking unit disposed downstream of the hydroprocessing unit and configured to receive and crack the hydroprocessed pyrolysis oil without naphtha dilution.

[0021] FIG. 1 is a diagrammatic representation of an embodiment of a system 100 for processing of pyrolysis oil 102. The pyrolysis oil 102 may be formed by pyrolyzing mixed plastic waste (MPW). For example, the MPW may be heated to temperatures ranging from 400 °C to 500 °C under anaerobic conditions to yield pyrolysis oil. As noted, while the pyrolysis oil 102 substantially contains small hydrocarbon molecules, at least some of these molecules can also contain heteroatoms, such as oxygen, nitrogen, and halide (e.g., chloride, bromide, fluoride) atoms, depending on the composition of the MPW and the pyrolysis process.

[0022] For the embodiment illustrated in FIG. 1, the system 100 includes a pretreatment zone 104 that processes the pyrolysis oil 102 to generate pretreated pyrolysis oil 106 (also referred to herein as upgraded pyrolysis oil), a hydrotreatment zone 108 (also referred to herein as a hydroprocessing zone) that hydrotreats the pretreated pyrolysis oil 106 to generate hydrotreated pyrolysis oil 110, and a steam cracking zone 112 that processes the hydrotreated pyrolysis oil 110 to generate hydrocarbon products 114. In some implementations, the system 100 may include fewer zones or the zones may be disposed in separate geographical locations. For example, in some implementations, the system 100 includes the pretreatment zone 104, and optionally the hydrotreatment zone 108, disposed at a first location to pretreat, and to optionally hydrotreat, the pyrolysis oil 102 prior transport to a second location that includes the steam cracking zone 112. It may be appreciated that the pretreated pyrolysis oil 106 and / or the hydrotreated pyrolysis oil 110 desirably demonstrate substantially lower gum formation during storage and / or transport than the pyrolysis oil 102. For example, in an embodiment, the pretreated pyrolysis oil 106 includes less than about 0.02 wt. % of gum impurities after 30 days of storage and / or transport.

[0023] For the embodiment illustrated in FIG. 1, the pretreatment zone 104 includes a gas stripping subzone 116, a solvent extraction subzone 118, and an adsorption subzone 120. In some embodiments, the pretreatment zone 104 includes only the gas stripping subzone 116 and the solvent extraction subzone 118, while in other embodiments, the pretreatment zone 104 includes only the gas stripping subzone 116 and the adsorption subzone 120. In some embodiments, the pretreatment zone 104 includes only the gas stripping subzone 116. Examples of the gas stripping subzone 116, the solvent extraction subzone 118, and the adsorption subzone 120 are discussed below with respect to FIGS. 3, 5, and 6. As discussed herein, the one or more subzones of the pretreatment zone 104 are designed to remove a substantial quantity of one or more heteroatomcontaining species (e.g., chlorine-containing species) of the pyrolysis oil 102 prior tohydrotreatment, which can desirably decrease issues with fouling and / or corrosion in the downstream equipment of the hydrotreatment zone 108 and / or the steam cracking zone 112. As noted, in certain embodiments, the pretreated pyrolysis oil 106, which is stabilized by the pretreatment, may be stored and / or transported to another location, and may form substantially less gum compared to the pyrolysis oil 102 being stored and / or transported under similar conditions.

[0024] For the embodiment illustrated in FIG. 1, the hydrotreatment zone 108 includes a hydrotreatment reactor 122, also referred to herein as a hydroprocessing unit or hydroprocessing reactor. The hydrotreatment reactor 122 is designed to hydroprocess the pretreated pyrolysis oil 106 to yield the hydrotreated pyrolysis oil 110. In some embodiments, the hydrotreatment reactor 122 performs a two stage hydroprocessing of the pretreated pyrolysis oil 106, in which the first stage involves saturating diolefins present within the pretreated pyrolysis oil 106, and the second stage involves removing heteroatoms (e.g., nitrogen, oxygen, chloride) from the hydrocarbons remaining within the within the pretreated pyrolysis oil 106. It is presently recognized that, when the pyrolysis oil 102 is provided directly to the hydrotreatment zone 108 without traversing the pretreatment zone 104, the higher heteroatom content of the pyrolysis oil can result in the formation of a substantial quantity of corrosive species (e.g., hydrogen chloride (HC1) gas), which can undesirably corrode the hydrotreatment reactor 122 and / or other downstream equipment. Additionally, when the pyrolysis oil includes a substantial chloride and nitrogen heteroatom content, this can result in the formation of a substantial quantity of undesirable ammonium chloride (NH3CI), which can promote fouling within the hydrotreatment reactor 122 and / or other downstream equipment. As noted, in certain embodiments, the hydrotreated pyrolysis oil 110, which is stabilized by the pretreatment and the hydrotreatment, may be stored and / or transported to another location, and may form substantially less gum compared to the pyrolysis oil 102 being stored and / or transported under similar conditions.

[0025] For the embodiment illustrated in FIG. 1, the steam cracking zone 112 includes a steam cracker 124 and a separation subzone 126. The steam cracker 124 processes the hydrotreated pyrolysis oil 110 at elevated temperatures using steam to crack the hydrocarbon species present within the hydrotreated pyrolysis oil 110 to yield a mixed hydrocarbon stream that contains hydrogen (H2), paraffins (e.g., C1-12 alkanes), olefins, and aromatics. When the hydrotreated pyrolysis oil 110 includes a substantial quantity of HC1 or NH3CI, corrosion and / or fouling issuescan arise within the steam cracker 124. It is further presently recognized that pyrolysis oil is typically heavily diluted with naphtha prior to steam cracking; however, by processing the pyrolysis oil 102 using the pretreatment zone 104 and the hydrotreatment zone 108, present embodiments beneficially enable steam cracking of the hydrotreated pyrolysis oil 110 to be steam cracked with little or no naphtha dilution (e.g., using a weight ratio of hydrotreated pyrolysis oil to naphtha from about 0.1 to about 1, or greater than 0.5, in some embodiments). The separation subzone 126 includes one or more separation units (e.g., distillation columns, fractionation columns) that receive and separate out the various hydrocarbon products 114 into product streams (e.g., an ethene product stream, a propene product stream, a butenes product stream, a fuel gas stream, a pyrolysis gasoline stream), which may be collected and sold as products or serve as inputs to other hydrocarbon processing or manufacturing operations (e.g., isomerization, metathesis, polymer production, fuel production).

[0026] FIG. 2 is a diagrammatic representation of an embodiment of a method 200 for pretreating pyrolysis oil 102 to yield pretreated pyrolysis oil 106, and for hydrotreating the pretreated pyrolysis oil 106 to yield hydrotreated pyrolysis oil 110. The method 200 begins with the pyrolysis oil 102 entering the pretreatment zone 104 for pretreatment. The method 200 includes the step 202 of pretreating pyrolysis oil using a gas stripping operation at elevated temperature to remove a substantial portion of at least certain chlorinated species having a high vapor pressure, such as C2-8 chloroalkanes (e.g., chloroethane, di chloroethane, chloromethylbutanes, chloropentane, chlorocyclopentane, chlorooctanes). For example, in certain embodiments, the chlorine-containing species removed by the gas stripping operation may include chloroethane, 2- chloroethanol, 1,2-di chloroethane, l-chloro-2-propanol, 2-chloro-ethanol acetate, or chloroethyl benzene, or any combination thereof. The gas stripping operation of step 202 is performed within the gas stripping subzone 116 illustrated in FIG. 1.

[0027] For the embodiment illustrated in FIG. 2, during the gas stripping operation, the pyrolysis oil 102 is heated and contacted with a stripping gas that volatilizes and removes one or more volatile (e.g., high vapor pressure) heteroatom-containing species from the pyrolysis oil. The stripping gas used for the gas stripping operation may contain steam, nitrogen (N2), or carbon dioxide (CO2), or a combination thereof. In certain embodiments, the one or more stripping gases do not include or are substantial free of hydrogen (H2). The gas stripping operation occurs at elevated temperatures, for example, with a liquid temperature from about 120 degrees Celsius (°C)to about 250 °C and a gas temperature from about 30 °C to about 100 °C. In some embodiments, the stripping time extends from about 1 minute to about 60 minutes. In some embodiments, the ratio of stripping gas to pyrolysis oil ranges from about 0.05 wt. % to about 50 wt. %, or a weight ratio of pyrolysis oil to stripping gas greater than about 10: 1. It is presently recognized that the disclosed elevated-temperature gas stripping operation is distinct from simple degassing operations, which typically involve bubbling gas through pyrolysis oil at room temperature to remove oxygen dissolved in the pyrolysis oil, as such degassing operations fail to effectively remove heteroatom-containing species from the pyrolysis oil. For clarity, after the gas stripping operation, the resulting pyrolysis oil may be referred to herein as gas-stripped pyrolysis oil.

[0028] For the embodiment illustrated in FIG. 2, the method includes the step 204 of further pretreating the gas-stripped pyrolysis oil using a solvent extraction operation to remove a substantial portion of at least medium-polarity chlorinated species (e.g., chloroethers, chloroalcohols, chloroesters). The solvent extraction operation of step 204 is performed within the solvent extraction subzone 118 illustrated in FIG. 1. The solvent extraction operation is performed using at least one polar solvent, such as dimethylsulfoxide (DMSO), N-methylpyrrolidone (NMP), dimethylformamide (DMF), ethylene glycol, water, or a combination thereof. For example, in an embodiment, the solvent extraction operation may be performed using water as the polar solvent at a ratio of water to pyrolysis oil of 1 :2 at a temperature from about 10 °C to about 80 °C, which may remove about 90% or more of chloroalcohols (e.g., chloroethanol) from the pyrolysis oil. During the solvent extraction operation, the medium-polarity chlorinated species, and potentially certain nitrogen-containing species, are dissolved within the denser polar solvent layer, which is separated from the less-dense, purified pyrolysis oil. In some embodiments, the extraction solvent may be subsequently purified to remove the dissolved species and recycled in another solvent extraction operation to reduce operational cost and reduce waste. In some embodiments of the method 200, step 204 may be omitted to simplify the method / system and to reduce installation, maintenance, and / or operational costs. For clarity, after the solvent extraction operation, the resulting pyrolysis oil may be referred to herein as solvent-extracted pyrolysis oil.

[0029] For the embodiment illustrated in FIG. 2, the method includes the step 206 of further pretreating the gas-stripped pyrolysis oil or the solvent-extracted pyrolysis oil using an adsorption operation to remove at least chloride-containing species (chlorinates), nitrogen-containing species (nitrogenates), and oxygen-containing species (oxygenates). The adsorption operation of step 206is performed within the adsorption subzone 120 illustrated in FIG. 1. During the adsorption operation, the pyrolysis oil is exposed to an adsorbent that interacts with and sequesters heteroatom-containing species from the pyrolysis oil. In some embodiments, the adsorbent contains silica gels, Zeolite 13X adsorbents, activated carbon, activated alumina, clays, solid acids / bases, or ion-exchange resins, or combinations thereof. In some embodiments of the method 200, step 206 may be omitted to simplify the method / system and to reduce installation, maintenance, and / or operational costs. For clarity, after the adsorption operation, the resulting pyrolysis oil may be referred to herein as adsorbent-treated pyrolysis oil.

[0030] For the embodiment illustrated in FIG. 2, the pretreated pyrolysis oil 106 exits the pretreatment zone 104 and enters the hydrotreatment zone 108. As noted, in some embodiments, the pretreated pyrolysis oil 106 corresponds to the gas-stripped pyrolysis oil generated in step 202. In some embodiments, the pretreated pyrolysis oil 106 corresponds to the gas-stripped and solvent extracted pyrolysis oil generated in step 204. In some embodiments, the pretreated pyrolysis oil 106 corresponds to the gas-stripped and adsorbent-treated pyrolysis oil, or the gas-stripped, solvent-extracted, and adsorbent-treated pyrolysis oil, generated in step 206. Since each of the potential pretreatment operations target specific heteroatom-containing species of the pyrolysis oil 102, in some embodiments, particular pretreatment operations are selected based on the composition of the pyrolysis oil 102. For example, in some embodiments, a pyrolysis oil analyzer (e.g., a gas chromatographic analyzer) analyzes the pyrolysis oil to determine the heteroatom content and distribution, and based on this analysis, conditionally routes the pyrolysis oil 102 to step 202, step 204, and / or step 206 to yield the pretreated pyrolysis oil 106. For such embodiments, this enables lower operating cost and higher production rates for situations in which the pyrolysis oil 102 has a low heteroatom content and / or fewer heteroatom-containing species, while also enabling flexibility to process pyrolysis oil 102 having a higher heteroatom content and / or more heteroatom-containing species.

[0031] In some embodiments, the pretreatment steps 202, 204, and / or 206 are performed in different orders. For example, in some embodiments, pretreatment step 202 may be followed by pretreatment step 206 and then pretreatment step 204. In some embodiments, pretreatment step 204 may be performed first, followed by pretreatment step 202 and then pretreatment step 206. In some embodiments, pretreatment step 204 may be performed first, followed by pretreatment step 206 and then pretreatment step 202. In some embodiments, pretreatment step 206 may beperformed first, followed by pretreatment step 202 and then pretreatment step 204. In some embodiments, pretreatment step 206 may be performed first, followed by pretreatment step 204 and then pretreatment step 206. In some embodiments, only two of the pretreatment steps are performed. For example, in some embodiments, the pretreatment step 202 is performed first, followed by either the pretreatment step 204 or the pretreatment step 206. In some embodiments, the pretreatment step 204 is performed first, followed by either the pretreatment step 202 or the pretreatment step 206. In some embodiments, the pretreatment step 206 is performed first, followed by either the pretreatment step 202 or the pretreatment step 204.

[0032] For the embodiment illustrated in FIG. 2, the pretreated pyrolysis oil 106 enters the hydrotreatment zone 108, which includes the hydrotreatment reactor 122 illustrated in FIG. 1. During hydrotreatment, the pretreated pyrolysis oil 106 is generally exposed to a hydrotreatment catalyst at elevated temperature and in the presence of hydrogen gas (H2). For the embodiment illustrated in FIG. 2, the hydrotreatment operation proceeds over two stages. Accordingly, the method 200 includes the step 208 in which a first hydrotreatment stage is performed to saturate diolefins present within the pretreated pyrolysis oil 106 under relatively milder conditions. Subsequently, the method 200 includes the step 210 in which a second hydrotreatment stage is performed to remove heteroatoms remaining in the pretreated pyrolysis oil 106 at relatively higher temperatures. During hydrotreatment, and especially during the second stage of step 210, nitrogen heteroatoms are converted into ammonia (NH3) and chloride heteroatoms are converted into HC1, which can promote corrosion issues in the hydrotreatment zone 108 and in other downstream equipment (e.g., the steam cracker). Additionally, upon cooling, these species can react and form NH3CI precipitate as the hydrotreated pyrolysis oil 110 cools after hydrotreatment, which can promote fouling in downstream equipment (e.g., the steam cracker). As such, the pretreatment steps 202, 204, and / or 206 enable substantial reductions in the amount of heteroatom species, especially chlorinates and nitrogenates, within the pyrolysis oil, which limits or eliminates corrosion and / or fouling issues within the hydrotreatment zone 108, as well as other downstream zones (e.g., the steam cracking zone).

[0033] FIG. 3 is a diagrammatic representation of an embodiment of a gas stripping subzone 116 for performing the gas stripping operation during the pretreatment of pyrolysis oil 102 to yield gas-stripped pyrolysis oil 300, in accordance with step 202 of the method 200 illustrated in FIG. 2. While indicated as pyrolysis oil 102 in the drawing, it should be appreciated that, in someembodiments, the pyrolysis oil may be fresh pyrolysis oil, solvent-extracted pyrolysis oil, or adsorbent-treated pyrolysis oil, as discussed above. The example gas stripping subzone 116 illustrated in FIG. 3 includes a gas stripper 302 (also referred to herein as a gas stripping unit), which includes a reboiler 304 and at least one condenser 306. The illustrated gas stripping subzone 116 includes a controller 308, which may be a controller of the entire hydrocarbon processing system 100 illustrated in FIG. 1 or a sub-controller of the gas stripping subzone 116 in different embodiments.

[0034] For the embodiment illustrated in FIG. 3, the controller 308 includes a memory 310 (e.g., a random-access memory (RAM), read-only memory (ROM), a solid-state disk (SSD), or other suitable memory or storage device) that stores processor-executable instructions to implement, for example, the control method FIG. 4. The controller 308 includes a processor 312 (e.g., a central processing unit (CPU), a graphics processing unit (GPU), one or more co-processing units) that executes the instructions stored in the memory 310 to implement, for example, the control method of FIG. 4. For the illustrated embodiment, the controller 308 is communicatively connected to a pyrolysis oil analyzer 314 (e.g., a gas chromatographic analyzer) to receive measurements or data indicating the content and / or distribution of one or more heteroatom-containing species present within the gas-stripped pyrolysis oil 300. The controller 308 is communicatively connected to the reboiler 304 to receive indications of the current heat duty of the reboiler, and to provide suitable control signals to vary the heat duty of the reboiler (e.g., from about 50 kilowatts (kW) to about 200 kW). The controller 308 is communicatively connected to the condenser 306 to receive indications of the current heat duty of the condenser, and to provide suitable control signals to vary the heat duty of the condenser (e.g., from about 50 kW to about 200 kW). The controller 308 is communicatively connected to a flow control valve 316 to provide suitable control signals to regulate the flow of the pyrolysis oil 102 into the gas stripper 302, and communicatively connected to a flow control valve 318 to provide suitable control signals to regulate the flow of the one or more stripping gases 320 into the gas stripper 302. The communicative connection between the controller 308 and the various components of the gas stripping subzone 116 may be a wired or wireless connection in different embodiments.

[0035] For the embodiment illustrated in FIG. 3, the pyrolysis oil 102 and the one or more stripping gases 320 enter the gas stripper 302. In some embodiments, the gas stripper 302 functions similarly to a distillation column having three distillation stages. The liquid phase 322, whichcontains condensed pyrolysis oil, exits at or near the bottom of the gas stripper 302 and is directed to the reboiler 304, which heats the pyrolysis oil to a predefined temperature before it is routed back to the gas stripper. The gas phase 324, which contains the one or more stripping gases and one or more volatile components (e.g., volatile heteroatom-containing species) of the pyrolysis oil, exits at or near the top of the gas stripper 302 and is directed to a gas treatment unit 326. The gas treatment unit 326 may vary in different embodiments depending on the one or more stripping gases 320 that are used. For embodiments in which the one or more stripping gases 320 include steam, the gas phase 324 may be cooled and condensed by a heat exchanger of the gas treatment unit 326 before being provided to a waste-water stripper to remove the stripped components of the pyrolysis oil from the water. For embodiments in which the one or more stripping gases 320 include N2, the gas treatment unit 326 may contact the gas phase 324 with an adsorbent to interact with and sequester the stripped components of the pyrolysis oil before the gas phase is routed for flaring. In some embodiments, from about 0.5 wt. % to about 20 wt. % of the pyrolysis oil 102 is lost to the gas phase 324 during the gas stripping operation. After a predetermined amount of stripping time, the reboiler 304 is deactivated and the gas-stripped pyrolysis oil 300 exits the gas stripping subzone 116. For embodiments in which the gas stripping operation is the only or is the final pretreatment operation, the gas-stripped pyrolysis oil 300 may retain at least a portion of the heat from the gas stripping operation before proceeding to hydrotreatment, which may advantageously reduce the energy expenditure to heat the pyrolysis oil during hydrotreatment.

[0036] FIG. 4 is a diagrammatic representation of an embodiment of a method 400 in which the controller 308 controls operation of the embodiment of the gas stripping subzone 116 illustrated in FIG. 3. The method 400 includes the step 402, in which the controller 308 provides suitable control signals to set a flow rate of pyrolysis oil into the gas stripper, a flow rate of the stripping gas into the gas stripper, a heat duty of the reboiler of the gas stripper, a heat duty of the condenser of the gas stripper, a reflux ratio of the gas stripper, and a gas stripping time, in accordance with initial predefined values. In certain embodiments, the initial predefined values are selected based on an initial analysis of the heteroatom-containing species content and / or distribution of the pyrolysis oil prior to the gas stripping operation. The method 400 includes the step 404, in which the controller 308 receives, from the pyrolysis oil analyzer 314, an analysis of the liquid phase 322. The analysis may indicate the content and / or distribution of heteroatom-containing species present within the liquid phase 322. In some embodiments, the analysis is particularly directed tothe content and distribution of particular volatile heteroatom-containing species (e.g., chloroalkanes) present within the liquid phase 322. In some embodiments, the analysis is performed relative to an initial analysis of the content and / or distribution of heteroatom-containing species present within the pyrolysis oil prior to beginning the gas stripping operation.

[0037] For the embodiment illustrated in FIG. 4, the method 400 includes step 406, in which the controller 308 determines whether the amount of one or more volatile heteroatom-containing species in the liquid phase 322 is greater than predefined threshold value. Responsive to the amount of the one or more volatile heteroatom-containing species in the liquid phase 322 being greater than the predefined threshold value, in step 408, the controller 308 determines a new flow rate of pyrolysis oil into the gas stripper, a new flow rate of the stripping gas into the gas stripper, a new heat duty of the reboiler of the gas stripper, a new heat duty of the condenser of the gas stripper, a new reflux ratio of the gas stripper, or a new gas stripping time, or a combination thereof, based on the amount of volatile heteroatom-containing species in the liquid phase. Subsequently, in step 410, the controller 308 provides suitable control signals to set the new flow rate of pyrolysis oil into the gas stripper, the new flow rate of the stripping gas into the gas stripper, the new heat duty of the reboiler of the gas stripper, the new heat duty of the condenser of the gas stripper, the new reflux ratio of the gas stripper, or the new gas stripping time, or a combination thereof. For example, in step 408, the controller 308 may determine based on a comparison of the analysis of step 404 to a previous analysis that the removal of the one or more volatile heteroatom-containing species is proceeding at a desired rate, and in step 410 provide control signals to only increase the gas stripping time. In another example, the controller 308 may determine based on a comparison of the analysis of step 404 to a previous analysis that the removal of the one or more volatile heteroatom-containing species is proceeding at too slowly, and in step 410 provide control signals to modify other parameters of the gas stripping operation to increase the removal rate. As illustrated, after providing the control signals to adjust one or more parameters of the gas stripping operation, the controller 308 continues the gas stripping operation and returns to step 404 to receive a subsequent analysis of the liquid phase 322. In step 406, responsive to the amount of the one or more volatile heteroatom-containing species in the liquid phase 322 being less than or equal to the predefined threshold value, in step 412, the controller 308 provides suitable control signals to conclude the gas stripping operation and allow the gas-stripped pyrolysis oil 300 to proceed to other pretreatment operations or hydrotreatment, as discussed above.

[0038] FIG. 5 is a diagrammatic representation of an embodiment of a solvent extraction subzone 118 for performing the solvent extraction operation during the pretreatment of pyrolysis oil 102 to yield solvent-extracted pyrolysis oil 500, in accordance with step 204 of the method 200 illustrated in FIG. 2. While indicated as pyrolysis oil 102 in the drawing, it should be appreciated that, in some embodiments, the pyrolysis oil may be fresh pyrolysis oil, gas-stripped pyrolysis oil, or adsorbent-treated pyrolysis oil. The example solvent extraction subzone 118 illustrated in FIG. 5 includes a solvent extraction unit 502 that is designed to receive and mix the pyrolysis oil 102 and one or more polar extraction solvents 504 (e.g., DMSO, NMP, DMF, ethylene glycol, water). After a predetermined amount of contact time, the denser phase 506 that contains the one or more extraction solvents having one or more dissolved heteroatom-containing species (e.g., chloroethers, chloroalcohols, chloroesters) is separated from the less-dense solvent-extracted pyrolysis oil 500. In some embodiments, the denser phase 506 is directed to a solvent recovery unit 508 that uses a suitable method (e.g., distillation, adsorbent treatment) to remove the dissolved heteroatom-containing species from the one or more extraction solvents to enable the one or more extraction solvents to be used in another solvent-extraction operation.

[0039] FIG. 6 is a diagrammatic representation of an embodiment of an adsorption subzone 120 for performing the adsorption treatment operation during the pretreatment of pyrolysis oil 102 to yield adsorbent-treated pyrolysis oil 600, in accordance with step 206 of the method 200 illustrated in FIG. 2. While indicated as pyrolysis oil 102 in the drawing, it should be appreciated that, in some embodiments, the pyrolysis oil may be fresh pyrolysis oil, gas-stripped pyrolysis oil, or solvent-extracted pyrolysis oil. The example adsorption subzone 120 illustrated in FIG. 6 includes an adsorption unit 602 that includes an adsorbent 604, as discussed above. In certain embodiments, the adsorbent 604 may be arranged in a fixed bed. The adsorption unit 602 receives and contacts the pyrolysis oil 102 with the adsorbent 604, such that the adsorbent 604 interacts with and sequesters one or more heteroatom-containing species from the pyrolysis oil (e.g., chlorinates, nitrogenates, oxygenates) to yield the adsorbent-treated pyrolysis oil 600. In some embodiments, the pyrolysis oil 102 may proceed through a pyrolysis oil recycle 606 one or more times during the adsorption operation to ensure sufficient contact time with the adsorbent 604. In some embodiments, after one or more adsorption operations, the adsorbent 604 may be replaced, and the spent adsorbent 604 may be chemically and / or physically treated to remove the sequestered heteroatom-containing species to enable recycling of the adsorbent 604.EXAMPLES

[0048] Example 1: In a first example, a steam gas stripping operation of fresh pyrolysis oil was modeled using commercially available modeling software. Prior to the gas stripping operation, the fresh pyrolysis oil was modeled as having an initial chloride content of 288 parts-per-million (ppm) due to the presence of one or more chloride-containing species in the pyrolysis oil. Within the model, the pyrolysis oil was introduced into the gas stripper at a rate of 1250 kilograms per hour (kg / h), while the stripping steam was introduced at a rate of 100 kg / h. For this example, the gas stripper was modeled as having three stages and as operating at a liquid temperature of 175 °C and a vapor temperature of 58 °C. At the conclusion of the modeled gas stripping operation, the model predicted that the pyrolysis oil loss would be 4% and predicted that the chloride content would decrease to 69 ppm, representing a 76% decrease in the chloride content of the pyrolysis oil during the steam gas stripping operation of Example 1. Additionally, the particular chlorine-containing species predicted to be removed are indicated in Table 1.

[0049] Table 1. Chlorine-containing species removed in Example 1.

[0050] Example 2: In a second example, a N2 gas stripping operation of fresh pyrolysis oil was modeled using commercially available modeling software. Prior to the gas stripping operation, the fresh pyrolysis oil was modeled as having an initial chloride content of 288 ppm due to the presence of one or more chloride-containing species in the pyrolysis oil. Within the model, the pyrolysis oil was introduced into the gas stripper at a rate of 1250 kilograms per hour (kg / h), while the N2 stripping gas was introduced at a rate of 100 kg / h. For this example, the gas stripper was modeled as having three stages and as operating at a liquid temperature of 151 °C and a vaportemperature of 60 °C. At the conclusion of the modeled gas stripping operation, the model predicted that the pyrolysis oil loss would be 4% and predicted that the chloride content would decrease to 72 ppm, representing a 75% decrease in the chloride content of the pyrolysis oil during the N2 gas stripping operation of Example 2.

[0051] Other objects, features, and advantages of the disclosure will become apparent from the foregoing figures, detailed description, and examples. It should be understood, however, that the figures, detailed description, and examples, while indicating specific examples of the disclosure, are given by way of illustration only and are not meant to be limiting. Additionally, it is contemplated that changes and modifications within the spirit and scope of the disclosure will become apparent to those skilled in the art from the detailed description. In further examples, features from specific examples may be combined with features from other examples. For example, features from one example may be combined with features from any of the other examples. In further examples, additional features may be added to the specific examples described herein.

Claims

CLAIMSWhat is claimed is:

1. A method, comprising: pretreating pyrolysis oil to yield pretreated pyrolysis oil, the pretreating including decreasing an amount of a first set of chloride-containing species in the pyrolysis oil via a gas stripping operation at elevated temperatures; and performing a hydroprocessing operation on the pretreated pyrolysis oil to yield hydroprocessed pyrolysis oil.

2. The method of claim 1, comprising pyrolyzing mixed plastic waste to yield the pyrolysis oil.

3. The method of any of claims 1 or 2, wherein the first set of chloride-containing species substantially contains chloroalkanes.

4. The method of any of claims 1-3, wherein the first set of chloride-containing species includes chloroethane, 2-chloroethanol, 1,2-di chloroethane, l-chloro-2-propanol, 2- chloro-ethanol acetate, or chloroethylbenzene, or any combination thereof.

5. The method of any of claims 1-4, wherein the elevated temperatures include a liquid temperature from about 120 degrees Celsius (°C) to about 250 °C, a vapor temperature from about 30 °C to about 100 °C, or a combination thereof.

6. The method of any of claims 1-5, wherein the gas stripping operation comprises providing a gas stream into the pyrolysis oil to decrease the amount of the first set of chloride-containing species in the pyrolysis oil, wherein the gas stream comprises steam, nitrogen (N2), or carbon dioxide (CO2), or a combination thereof.

7. The method of any of claims 1-6, wherein pretreating the pyrolysis oil comprises decreasing an amount of a second set of chloride-containing species, or a first set of nitrogen-containing species, or a combination thereof, in the pyrolysis oil via a solventextraction operation using a polar solvent, wherein the polar solvent includes dimethylsulfoxide (DMSO), N-methylpyrrolidone (NMP), dimethylformamide (DMF), ethylene glycol, water, or a combination thereof, and wherein the second set of chloride- containing species includes chloroethers, chloroalcohols, or chloroesters, or a combination thereof.

8. The method of claim 7, wherein pretreating the pyrolysis oil comprises decreasing an amount of a third set of chloride-containing species, a second set of nitrogen-containing species, or a first set of oxygen-containing species, or a combination thereof, in the pyrolysis oil via an adsorption operation using one or more adsorbents, wherein the one or more adsorbents comprise silica gel, zeolites, activated carbon, alumina, clays, solid acids, solid bases, or ion-exchange resins, or a combination thereof.

9. The method of any of claims 1-8, wherein the pretreated pyrolysis oil includes less than 0.02 weight percent (wt. %) gum impurities after 30 days.

10. The method of any of claims 1-9, comprising: dissolving the hydroprocessed pyrolysis oil in naphtha, wherein a weight ratio of hydroprocessed pyrolysis oil to naphtha is greater than 0.5; and steam cracking the hydroprocessed pyrolysis oil to yield a plurality of hydrocarbon products.

11. A pyrolysis oil processing system, comprising: a gas stripping unit, wherein the gas stripping unit is configured to contact a pyrolysis oil with one or more stripping gases at elevated temperatures to extract a portion of a first set of chloride-containing impurities from the pyrolysis oil, yielding a gas stream that contains the portion of the chloride-containing impurities and yielding a liquid stream that contains pretreated pyrolysis oil; and a hydroprocessing unit disposed downstream of the gas stripping unit and configured to receive and hydroprocess the pretreated pyrolysis oil to yield hydroprocessed pyrolysis oil.

12. The pyrolysis oil processing system of claim 11, wherein the one or more stripping gases contain steam, nitrogen, or carbon dioxide, or a combination thereof, wherein the one or more stripping gases are free of hydrogen, wherein the elevated temperatures include a liquid temperature from about 120 degrees Celsius (°C) to about 250 °C, a vapor temperature from about 30 °C to about 100 °C, or a combination thereof, wherein the gas stripping unit is configured to extract at least 70% of the first set of chloride-containing impurities from the pyrolysis oil, and wherein the first set of chloride-containing impurities includes chloroethane, 2-chloroethanol, 1,2-di chloroethane, l-chloro-2- propanol, 2-chloro-ethanol acetate, or chloroethyl benzene, or any combination thereof.

13. The pyrolysis oil processing system of claims 11 or 12, comprising a liquid extraction unit disposed downstream of the gas stripping unit and upstream of the hydroprocessing unit, wherein the liquid extraction unit is configured to contact the pretreated pyrolysis oil of the liquid stream with a polar solvent to extract a second set of chloride-containing impurities, or nitrogen-containing impurities, or a combination thereof, from the pretreated pyrolysis oil, and wherein the second set of chloride-containing impurities comprises chloroethers, chloroalcohols, or chloroesters, or a combination thereof.

14. The pyrolysis oil processing system of any of claims 11-13, comprising an adsorption unit disposed downstream of the gas stripping unit and upstream of the hydroprocessing unit, wherein the adsorption unit is configured to contact the pretreated pyrolysis oil with one or more adsorbents to extract nitrogen-containing impurities, oxygen-containing impurities, or a third set of chloride-containing impurities, or a combination thereof, from the pretreated pyrolysis oil.

15. The pyrolysis oil processing system of any of claims 11-14, comprising a steam cracking unit disposed downstream of the hydroprocessing unit and configured to receive and crack the hydroprocessed pyrolysis oil without naphtha dilution.

Images