WO2023100139A1

WO2023100139A1 - Methods for removal of silicon and chloride contaminants from mixed plastic waste based pyrolysis oil

Info

Publication number: WO2023100139A1
Application number: PCT/IB2022/061668
Authority: WO
Inventors: Amit Sharma; Fabrice Cuoq; Ziyu LIU; Safa Farajzadeh BIBALAN; Sreenivasa Rao
Original assignee: Sabic Global Technologies B.V.
Priority date: 2021-12-03
Filing date: 2022-12-01
Publication date: 2023-06-08

Abstract

Systems and methods for pretreating a raw mixed plastic waste pyrolysis oil to remove silicon and chloride contaminants using an aqueous alkaline hydroxide solution. Specifically, these systems and methods lead to at least about 30 weight percent reduction in the silicon compounds present in the pyrolysis oil and at least about 50 weight percent reduction in the chloride compounds in the pyrolysis oil.

Description

METHODS FOR REMOVAL OF SILICON AND CHLORIDE CONTAMINANTS FROM MIXED PLASTIC WASTE BASED PYROLYSIS OIL

Inventors: Amit Sharma

Fabrice Cuoq

Ziyu Liu

Safa Farajzadeh Bibalan Sreenivasa Rao

Cross-Reference to Related Applications

[0001] This application claims the benefit of and priority to U.S. Provisional Application No. 63/264,860, filed on December 3, 2021, which is incorporated herein by reference in its entirety.

Technical Field

[0002] The present disclosure generally relates to systems and methods for processing mixed plastic waste pyrolysis oil to remove silicon and chloride contaminants. More specifically, the present disclosure relates to systems and methods for processing mixed plastic waste pyrolysis oil to produce a feedstock that is usable for a refinery unit, such as a hydrotreater, or a hydrocracker, or a combination thereof.

Background

[0003] Pyrolysis oil (pyoil) from the mixed plastic waste is emerging as an alternative feedstock via chemical recycling. Pyoil contains several contaminants such as silicon, chlorides, nitrogen, oxygenates and other heavy species. These contaminants result in several detrimental effects, such as fouling and downstream catalyst poisoning. Moreover, products derived from the processing of pyoil are subjected to strict elemental requirements to be used as a replacement for the fossil-based feedstock, such as naphtha or fuels. Presence of silicon and chloride contaminants limit further downstream applications. One way of processing the pyoil is to send it to a hydrotreater unit to remove the hetero-atom impurities, such as the silicon, oxygen compounds, nitrogen compounds, and chloride compounds along with saturating the unsaturated species. A drawback of this process is that the hydrotreater catalyst tends to coke rapidly due to heavy components. Another drawback is that such a process requires a large quantity of hydrogen and a large reactor due to the high level of contamination present in the raw pyoil. Moreover, the hydrotreatment of pyoils with such contaminants requires expensive and special metallurgical equipment to address the corrosion issues.

Summary

[0004] To address these shortcomings in the art, Applicant has developed systems and methods for pretreating raw mixed plastic waste pyrolysis oil to remove silicon and chloride contaminants. Products formed from the hydrotreating of the pretreated mixed plastic waste pyrolysis oil can also be subject to further hydrocracking and distillation.

[0005] The pyrolysis oil can be a raw mixed plastic waste pyrolysis oil or can be certain specific fractions. The pyrolysis oil obtained from processing of raw mixed plastic waste can be fractionated to provide multiple fractions, such as a light liquid fraction with a boiling point less than about 170 degrees centigrade (°C), a middle liquid fraction with a boiling point ranging from about 170 °C to about 370 °C, and a heavy end fraction with a boiling point greater than about 370 °C. In certain instances, this heavy end fraction has a boiling point greater than about 400 °C. A mixture of all the three fractions is called a full range pyrolysis oil.

[0006] An embodiment of a method of treating a pyrolysis oil includes the step of supplying, to a reaction vessel, a pyrolysis oil containing a plurality of silicon compounds and a plurality of chloride compounds, mixing the pyrolysis oil with an aqueous alkaline hydroxide solution in the reaction vessel operated at a temperature ranging from about 15 °C to about 225 °C, allowing the mixture of the pyrolysis oil and the aqueous alkaline hydroxide solution to separate into an upgraded pyrolysis oil fraction and an aqueous fraction, extracting the upgraded pyrolysis oil fraction and optionally supplying it to a hydroprocessing unit. In certain embodiments, the pyrolysis oil is mixed with the aqueous alkaline hydroxide solution in the reaction vessel operated at a temperature ranging from about 15 °C to about 100 °C, or from about 15 °C to about 50 °C, or at room temperature. In certain embodiments, the alkaline hydroxide solution contains less than about 50 weight percent of the alkaline hydroxide. The aqueous alkaline hydroxide solution can contain less than about 20 weight percent of the alkaline hydroxide. The aqueous alkaline hydroxide solution can contain less than about 10 weight percent of the alkaline hydroxide. In certain embodiments, the alkaline hydroxide solution contains an amount of alkaline hydroxide ranging from about 1 weight percent to about 20 weight percent. The mixture of the pyrolysis oil and the aqueous alkaline hydroxide solution is separated into the upgraded pyrolysis oil fraction and the aqueous fraction by settling or coalescence. In certain embodiments, the upgraded pyrolysis oil fraction contains at least about 30 weight percent less of the plurality of silicon compounds than the plurality of silicon compounds in the pyrolysis oil and at least about 50 weight percent less of the plurality of chloride compounds than the plurality of chloride compounds in the pyrolysis oil. In certain embodiments, the upgraded pyrolysis oil fraction contains at least about 50 weight percent less of the plurality of silicon compounds than the plurality of silicon compounds in the pyrolysis oil and at least about 90 weight percent less of the plurality of chloride compounds than the plurality of chloride compounds in the pyrolysis oil.

[0007] An embodiment of a method of treating a pyrolysis oil includes the step of supplying, to a reaction vessel, a pyrolysis oil containing a plurality of silicon compounds and a plurality of chloride compounds, mixing the pyrolysis oil with a first aqueous alkaline hydroxide solution in the reaction vessel operated at a temperature ranging from about 15 °C to about 30 °C, allowing the mixture of the pyrolysis oil and the first aqueous alkaline hydroxide solution to separate into a first upgraded pyrolysis oil fraction and a first aqueous fraction, removing the first aqueous fraction from the reaction vessel, mixing the first upgraded pyrolysis oil fraction and a second aqueous alkaline hydroxide solution in the reaction vessel operated at a temperature ranging from about 15 °C to 30 °C, allowing the mixture of the first upgraded pyrolysis oil fraction and the second aqueous alkaline hydroxide solution to separate into a second upgraded pyrolysis oil fraction and a second aqueous fraction, removing the second aqueous fraction from the reaction vessel, mixing the second upgraded pyrolysis oil fraction with a third aqueous alkaline hydroxide solution in the reaction vessel operated at a temperature ranging from about 15 °C to 30 °C, allowing the mixture of the second upgraded pyrolysis oil fraction and the third aqueous alkaline hydroxide solution to separate into a third upgraded pyrolysis oil fraction and a third aqueous fraction, and extracting the third upgraded pyrolysis oil fraction and optionally supplying it to a hydroprocessing unit.

[0008] Each of the first aqueous alkaline hydroxide solution, the second aqueous alkaline hydroxide solution, and the third aqueous alkaline hydroxide solution has a pH of about 10 or greater. The third upgraded pyrolysis oil fraction contains at least about 30 weight percent less of the plurality of silicon compounds than the plurality of silicon compounds in the pyrolysis oil and at least about 50 weight percent less of the plurality of chloride compounds than the plurality of chloride compounds in the pyrolysis oil. In certain embodiments, the third upgraded pyrolysis oil fraction contains at least about 30 weight percent less of the plurality of silicon compounds than the plurality of silicon compounds in the pyrolysis oil and at least about 80 weight percent less of the plurality of chloride compounds than the plurality of chloride compounds in the pyrolysis oil. In certain embodiments, the third upgraded pyrolysis oil fraction contains at least about 50 weight percent less of the plurality of silicon compounds than the plurality of silicon compounds in the pyrolysis oil and at least about 80 weight percent less of the plurality of chloride compounds than the plurality of chloride compounds in the pyrolysis oil. In certain embodiments, the third upgraded pyrolysis oil fraction contains at least about 50 weight percent less of the plurality of silicon compounds than the plurality of silicon compounds in the pyrolysis oil and at least about 90 weight percent less of the plurality of chloride compounds than the plurality of chloride compounds in the pyrolysis oil.

[0009] Methods disclosed herein can be used to treat a pyrolysis oil that is a light liquid fraction obtained from processing of raw mixed plastic waste pyrolysis oil at less than about 170 °C, defining a naphtha fraction. Methods disclosed herein can be used to treat a pyrolysis oil that is a medium liquid fraction obtained from processing of raw mixed plastic waste pyrolysis oil from about 170 °C to about 370 °C, defining a diesel fraction. Methods disclosed herein can be used to treat a pyrolysis oil that is a full range pyrolysis oil.

[0010] Embodiments include systems for treating a pyrolysis oil. One such system includes the following: (i) a reaction vessel operated at a temperature ranging from about 15 °C to about 30 °C and containing (a) a pyrolysis oil inlet configured to receive and supply to the reaction vessel a pyrolysis oil containing a plurality of silicon compounds and a plurality of chloride compounds,

(b) an alkaline hydroxide inlet configured to receive and supply to the reaction vessel an aqueous alkaline hydroxide solution containing less than about 20 weight percent of the alkaline hydroxide,

(c) a mixing element located inside the reaction vessel to facilitate mixing of the pyrolysis oil and the aqueous alkaline hydroxide solution, (d) an upgraded pyrolysis oil outlet configured to discharge an upgraded pyrolysis oil fraction that is produced by separation of the mixture of the pyrolysis oil and the aqueous alkaline hydroxide solution into the upgraded pyrolysis oil fraction and an aqueous fraction, and (e) an effluent outlet configured to supply the aqueous fraction to an alkaline hydroxide recycling unit and to discharge any solids formed during production of the upgraded pyrolysis oil fraction and the aqueous fraction; and (ii) the alkaline hydroxide recycling unit connected to and in fluid communication with the effluent outlet and configured to process the aqueous fraction and supply fresh aqueous alkaline hydroxide solution to the reaction vessel. The reaction vessel can also include a jacket heater operatively connected to an external wall of the reaction vessel. In certain embodiments, the system includes a hydrotreater unit connected to and in fluid communication with the upgraded pyrolysis oil outlet of the reaction vessel.

[0011] Still other aspects and advantages of these exemplary embodiments and other embodiments, 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 embodiments, and are intended to provide an overview or framework for understanding the nature and character of the claimed aspects and embodiments. 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 embodiments described herein are not mutually exclusive and may exist in various combinations and permutations.

Brief Description of the Drawings

[0012] The accompanying drawings, which are included to provide a further understanding of the embodiments of the present disclosure, are incorporated in and constitute a part of this specification, illustrate embodiments of the present disclosure, and together with the detailed description, serve to explain principles of the embodiments 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 embodiments 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 embodiments of the disclosure.

[0013] FIG. 1 is an illustration of a system for processing mixed plastic waste pyrolysis oil, according to an embodiment.

[0014] FIG. 2 is a schematic flowchart for a method of processing mixed plastic waste pyrolysis oil, according to an embodiment.

[0015] FIG. 3 is a schematic flowchart for a method of processing mixed plastic waste pyrolysis oil using multiple treatments with the alkaline hydroxide solution, according to an embodiment.

Detailed Description

[0016] The present disclosure describes various embodiments related to processes, devices, and systems for pretreating the raw mixed plastic waste pyrolysis oil. Also, provided here are systems and methods for processing the pretreated raw mixed plastic waste pyrolysis oil by subjecting it to further hydrotreating processes. Further embodiments may be described and disclosed.

[0017] In the following description, numerous details are set forth in order to provide a thorough understanding of the various embodiments. In other instances, well-known processes, devices, and systems may not have been described in particular detail in order not to unnecessarily obscure the various embodiments. Additionally, illustrations of the various embodiments may omit certain features or details in order to not obscure the various embodiments.

[0018] The description may use the phrases “in some embodiments,” “in various embodiments,” “in an embodiment,” or “in embodiments,” which may each refer to one or more of the same or different embodiments. Furthermore, the terms “comprising,” “including,” “having,” and the like, as used with respect to embodiments of the present disclosure, are synonymous. [0019] The term “about” or “approximately” are defined as being close to as understood by one of ordinary skill in the art. In one non-limiting embodiment, the terms are defined to be within 10%, preferably within 5%, more preferably within 1%, and most preferably within 0.5%.

[0020] The terms “reducing,” “reduced,” or any variation thereof, when used in the claims and/or the specification includes any measurable decrease or complete inhibition to achieve a desired result.

[0021] 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, that includes the component. In a non-limiting example, 10 grams of component in 100 grams of the material is 10 wt.% of component.

[0022] The words “comprising” (and any form of comprising, such as “comprise” and “comprises”), “having” (and any form of having, such as “have” and “has”), “including” (and any form of including, such as “includes” and “include”) or “containing” (and any form of containing, such as “contains” and “contain”) are inclusive or open-ended and do not exclude additional, unrecited elements or method steps.

[0023] Embodiments of the present disclosure include systems and methods for processing mixed plastic waste pyrolysis oil to remove silicon and chloride contaminants. More specifically, the present disclosure relates to systems and methods for processing mixed plastic waste pyrolysis oil to produce a feedstock that is usable for a refinery unit, such as a hydrotreater, or a hydrocracker, or a combination thereof. [0024] Embodiments include systems for treating a pyrolysis oil. One such system includes the following: (i) a reaction vessel operated at a temperature ranging from about 15 °C to about 225 °C and containing (a) a pyrolysis oil inlet configured to receive and supply to the reaction vessel a pyrolysis oil containing a plurality of silicon compounds and a plurality of chloride compounds,

[0025] In certain embodiments, the higher temperatures result in greater removal of silicon and chloride impurities, but can affect the amount of pyoil that is recovered in the liquid phase. The effect of increased temperatures on the recovery of the pyoil depends on the nature and hydrocarbon profile of the pyoil. [0026] These systems and methods for processing the pyrolysis oil reduce the level of silicon compounds and chloride compounds in the pyrolysis oil before being supplied to the downstream processing units in the hydrotreater feed. For example, this treatment step facilitates the reduction of hydrogen consumption in the hydrotreater.

[0027] In certain embodiments, the pyrolysis oil can be obtained from recycled or renewable organic material. These organic materials can contain fossil waste-based oils, waste oils, algal oils and microbial oils, plant based fats and oils, animal based fats and oils, or combinations thereof. In certain embodiments, the fossil waste-based pyrolysis oil can include waste plastic pyrolysis oil (WPPO), end-life-tire pyrolysis oil (ELTPO), used lubricating oil (ULO), or combinations thereof. The pyrolysis oil can be a raw mixed plastic waste pyrolysis oil or can be certain specific fractions. The raw mixed plastic waste can be processed to provide multiple fractions, such as a light liquid fraction with a boiling point less than about 170 °C, a middle liquid fraction with a boiling point ranging from about 170 °C to about 370 °C, and a heavy end fraction with a boiling point greater than about 370 °C. In certain instances, this heavy end fraction has a boiling point greater than about 400 °C. A mixture of all the three fractions constitutes a full range pyrolysis oil.

[0028] FIG. 1 is a schematic representation of the caustic wash arrangement to remove the silicon and chlorides from the pyoil stream. The system 100 includes a reaction vessel 102 that can be operated at a temperature ranging from about 15 °C to about 225 °C. The reaction vessel 102 can also include a jacket heater 104 operatively connected to an external wall of the reaction vessel 102. The reaction vessel can be one or more of a fixed bed, a moving bed, a fixed stirred unit, or a fluidized bed unit, either placed as a single unit, or as multiple units in series or in parallel to pretreat the raw mixed plastic waste pyrolysis oil stream. The fluidized bed unit can be an ebullated bed unit. In certain embodiments, the reaction vessel is a microwave heated reaction vessel. The reaction vessel can be equipped with a microwave heating system, including several components such as a microwave source, a receiver, a transmitter, and a shield.

[0029] In this system 100, a pyoil stream 106 is fed from the bottom through a pyrolysis oil inlet 108 configured to receive and supply to the reaction vessel. The aqueous alkaline hydroxide solution 110 is supplied to the reaction vessel 102 via an alkaline hydroxide inlet 112. A mixing element 114 is located inside the reaction vessel 102 to facilitate mixing of the pyrolysis oil and the aqueous alkaline hydroxide solution. In certain embodiments, the mixing element is one or more of an agitator, an impeller, a baffle, or a draft tube configured within the reactor to provide effective mixing of the first dehalogenated pyrolysis oil and water. In certain embodiments, the impeller is one of three types such as a propeller, paddle, or turbine, which generate either axial or radial flow of the fluids within the reactor.

[0030] In certain embodiments, the pyrolysis oil is mixed with the aqueous alkaline hydroxide solution in the reaction vessel operated at a temperature ranging from about 15 °C to about 150 °C, from about 15 °C to about 100 °C, or from about 15 °C to about 50 °C, or at room temperature. In certain embodiments, the alkaline hydroxide solution contains less than about 50 weight percent of the alkaline hydroxide. The aqueous alkaline hydroxide solution can contain less than about 20 weight percent of the alkaline hydroxide. The aqueous alkaline hydroxide solution can contain less than about 10 weight percent of the alkaline hydroxide. In certain embodiments, the alkaline hydroxide solution contains an amount of alkaline hydroxide ranging from about 1 weight percent to about 20 weight percent.

[0031] The reaction vessel 102 also includes an upgraded pyrolysis oil outlet 116 configured to discharge an upgraded pyrolysis oil fraction 118 that is produced by separation of the mixture of the pyrolysis oil and the aqueous alkaline hydroxide solution into the upgraded pyrolysis oil fraction and an aqueous fraction. The reaction vessel 102 also includes an effluent outlet 120 configured to supply the aqueous fraction 122 to an alkaline hydroxide recycling unit 124 and to discharge any solids formed during production of the upgraded pyrolysis oil fraction and the aqueous fraction. The waxy solid or deposits are recovered at the bottom and discharged as a waste stream 130 through a waste outlet 128. The system 100 includes an alkaline hydroxide recycling unit connected to and in fluid communication with the effluent outlet. The aqueous fraction is processed here to remove any contaminants and appropriate alkaline hydroxide is added to the processed aqueous fraction to align with the specification of the fresh aqueous alkaline hydroxide solution that is supplied to the reaction vessel. This processed aqueous fraction 126 is then recycled to the reaction vessel as a separate stream or in combination with the fresh aqueous alkaline hydroxide solution 110 via an alkaline hydroxide inlet 112. In certain embodiments, the system includes a hydrocarbon processing unit connected to and in fluid communication with the upgraded pyrolysis oil outlet of the reaction vessel. In certain embodiments, the hydrocarbon processing unit is one or more of a fluid catalytic cracking (FCC) unit, a hydrocracking unit, a decoking unit, a naphtha hydrotreatment unit, a hydrotreating unit, and a steam cracking unit.

[0032] The pyoil feed rate is controlled to provide the optimum residence time required for the removal of silicon and chloride compounds. Further, the vessel is provided with the heating jacket to supply heat and temperature (if required). The reaction mixture is left to react for a predetermined period of time and predetermined temperature preferably with mixing. Embodiments of the methods described herein are used to remove silicon compounds, chloride compounds, or combinations thereof from the pyrolysis oil by treating the pyrolysis oil with an aqueous basic solution under specific operating conditions. Silicon compounds include linear and cyclic siloxanes and derivatives. Chloride compounds include chloride salts and organic chloride compounds, such as chlorinated hydrocarbons, like chlorethanol or chlorobenzonitrile. The pyrolysis oil obtained from these treatment methods can further be processed in the steam cracker or hydrotreater units.

[0033] FIG. 2 is a schematic flowchart for a method 200 for processing mixed plastic waste pyrolysis oil, according to an embodiment. This method 200 includes the step 202 of supplying, to a reaction vessel, a pyrolysis oil containing a plurality of silicon compounds and a plurality of chloride compounds. This method 200 includes the step 204 of mixing the pyrolysis oil with an aqueous alkaline hydroxide solution in the reaction vessel operated at a temperature ranging from about 15 °C to about 225 °C, and the step 206 of allowing the mixture of the pyrolysis oil and the aqueous alkaline hydroxide solution to separate into an upgraded pyrolysis oil fraction and an aqueous fraction. This method 200 further includes the step 208 of extracting the upgraded pyrolysis oil fraction and the step 210 of optionally supplying it to a hydroprocessing unit.

[0034] The aqueous alkaline hydroxide solution can be a hydroxide of any one or more of Group I or Group 2 elements. For example, without limitations, the aqueous alkaline hydroxide solution can be one or more of lithium hydroxide, sodium hydroxide, potassium hydroxide, calcium hydroxide, or magnesium hydroxide. In certain embodiments, the aqueous alkaline hydroxide solution can be tetrabutylammonium hydroxide.

[0035] In certain embodiments, the pyrolysis oil is mixed with the aqueous alkaline hydroxide solution in the reaction vessel operated at a temperature ranging from about 15 °C to about 100 °C, or from about 15 °C to about 50 °C, or at room temperature. In certain embodiments, the alkaline hydroxide solution contains less than about 50 weight percent of the alkaline hydroxide. The aqueous alkaline hydroxide solution can contain less than about 20 weight percent of the alkaline hydroxide. The aqueous alkaline hydroxide solution can contain less than about 10 weight percent of the alkaline hydroxide. In certain embodiments, the alkaline hydroxide solution contains an amount of alkaline hydroxide ranging from about 1 weight percent to about 20 weight percent.

[0036] The mixture of the pyrolysis oil and the aqueous alkaline hydroxide solution is separated into the upgraded pyrolysis oil fraction and the aqueous fraction by settling or coalescence. In certain embodiments, the upgraded pyrolysis oil fraction contains at least about 30 weight percent less of the plurality of silicon compounds than the plurality of silicon compounds in the pyrolysis oil and at least about 50 weight percent less of the plurality of chloride compounds than the plurality of chloride compounds in the pyrolysis oil. In certain embodiments, the upgraded pyrolysis oil fraction contains at least about 50 weight percent less of the plurality of silicon compounds than the plurality of silicon compounds in the pyrolysis oil and at least about 90 weight percent less of the plurality of chloride compounds than the plurality of chloride compounds in the pyrolysis oil.

[0037] FIG. 3 is a schematic flowchart for a method 300 of processing mixed plastic waste pyrolysis oil using multiple treatments with the alkaline hydroxide solution, according to an embodiment. This method 300 includes the step 302 of supplying, to a reaction vessel, a pyrolysis oil containing a plurality of silicon compounds and a plurality of chloride compounds. This method 300 includes the step 304 of mixing the pyrolysis oil with a first aqueous alkaline hydroxide solution in the reaction vessel operated at a temperature ranging from about 15 °C to about 30 °C, and the step 306 of allowing the mixture of the pyrolysis oil and the first aqueous alkaline hydroxide solution to separate into a first upgraded pyrolysis oil fraction and a first aqueous fraction. In step 308, the first aqueous fraction is removed from the reaction vessel. This method 300 further includes the step 310 of mixing the first upgraded pyrolysis oil fraction and a second aqueous alkaline hydroxide solution in the reaction vessel operated at a temperature ranging from about 15 °C to 30 °C, and the step 312 of allowing the mixture of the first upgraded pyrolysis oil fraction and the second aqueous alkaline hydroxide solution to separate into a second upgraded pyrolysis oil fraction and a second aqueous fraction. In step 314, the second aqueous fraction is removed from the reaction vessel. This method 300 further includes the step 316 of mixing the second upgraded pyrolysis oil fraction with a third aqueous alkaline hydroxide solution in the reaction vessel operated at a temperature ranging from about 15 °C to 30 °C, and the step 318 of allowing the mixture of the second upgraded pyrolysis oil fraction and the third aqueous alkaline hydroxide solution to separate into a third upgraded pyrolysis oil fraction and a third aqueous fraction. In step 320, the third upgraded pyrolysis oil fraction is extracted, and in step 322, it is optionally supplied to a hydrocarbon processing unit. In certain embodiments, the hydrocarbon processing unit is one or more of a fluid catalytic cracking (FCC) unit, a hydrocracking unit, a decoking unit, a naphtha hydrotreatment unit, a hydrotreating unit, and a steam cracking unit.

[0038] Each of the first aqueous alkaline hydroxide solution, the second aqueous alkaline hydroxide solution, and the third aqueous alkaline hydroxide solution has a pH of about 10 or greater. In an embodiment, each of the first aqueous alkaline hydroxide solution, the second aqueous alkaline hydroxide solution, and the third aqueous alkaline hydroxide solution has a concentration of the alkali hydroxide equal to or greater than about 0.0 IM. The third upgraded pyrolysis oil fraction contains at least about 30 weight percent less of the plurality of silicon compounds than the plurality of silicon compounds in the pyrolysis oil and at least about 50 weight percent less of the plurality of chloride compounds than the plurality of chloride compounds in the pyrolysis oil. In certain embodiments, the third upgraded pyrolysis oil fraction contains at least about 30 weight percent less of the plurality of silicon compounds than the plurality of silicon compounds in the pyrolysis oil and at least about 80 weight percent less of the plurality of chloride compounds than the plurality of chloride compounds in the pyrolysis oil. In certain embodiments, the third upgraded pyrolysis oil fraction contains at least about 50 weight percent less of the plurality of silicon compounds than the plurality of silicon compounds in the pyrolysis oil and at least about 80 weight percent less of the plurality of chloride compounds than the plurality of chloride compounds in the pyrolysis oil. In certain embodiments, the third upgraded pyrolysis oil fraction contains at least about 50 weight percent less of the plurality of silicon compounds than the plurality of silicon compounds in the pyrolysis oil and at least about 90 weight percent less of the plurality of chloride compounds than the plurality of chloride compounds in the pyrolysis oil. [0039] Methods disclosed herein can be used to treat a pyrolysis oil that is a light liquid fraction obtained from processing of raw mixed plastic waste pyrolysis oil at less than about 170 °C, defining a naphtha fraction. Methods disclosed herein can be used to treat a pyrolysis oil that is a medium liquid fraction obtained from processing of raw mixed plastic waste pyrolysis oil from about 170 °C to about 370 °C, defining a diesel fraction. Methods disclosed herein can be used to treat a pyrolysis oil that is a full range pyrolysis oil.

EXAMPLES

[0040] Various examples provided below illustrate selected aspects of the various methods of using solid adsorbents to pretreat mixed plastic waste pyrolysis oil.

Example 1

[0041] A pyrolysis oil sample was prepared that contained the light liquid fraction obtained from processing of raw mixed plastic waste pyrolysis oil at less than about 170 °C (naphtha) and the medium liquid fraction obtained from processing of raw mixed plastic waste pyrolysis oil from about 170 °C to about 370 °C (diesel). The naphtha and the diesel components were present in a 2:

3 ratio. This sample had a silicon content of 550 ppm, an organic chloride content of 5450 ppm, and a total chloride content of 5560 ppm. Three alkaline hydroxide solutions were prepared containing approximately 10 wt.%, 30 wt.%, and 50 wt.% of sodium hydroxide in water. Each of the alkaline hydroxide solutions was added to the pyrolysis oil sample in a 1 :1 ratio, and each of the resulting mixtures was continuously mixed in the reaction vessel operated at 20 °C. After an hour, the mixture of the pyrolysis oil and the aqueous alkaline hydroxide solution was allowed to separate into an upgraded pyrolysis oil fraction and an aqueous fraction. About 90% of the pyrolysis oil sample was recovered as the upgraded pyrolysis oil fraction, in the instance when the 10 wt.% sodium hydroxide solution was used. About 70% of the pyrolysis oil sample was recovered as the upgraded pyrolysis oil fraction, in the instance when the 30 wt.% sodium hydroxide solution was used. About 25% of the pyrolysis oil sample was recovered as the upgraded pyrolysis oil fraction, in the instance when the 50 wt.% sodium hydroxide solution was used. The silicon and chloride content in the upgraded pyrolysis oil fraction were evaluated by inductively coupled plasma mass spectroscopy and the analytical method prescribed in UOP 779-08 for determining chloride in liquid hydrocarbons, respectively. The silicon content in each of the mixtures decreased by 50% to about 270 ppm and the chloride content decreased by 94% to about 312 ppm.

Example 2

[0042] The pyrolysis oil sample prepared in Example 1 was treated with two alkaline hydroxide solutions containing approximately 10 wt.% and 30 wt.% of sodium hydroxide in water. Each of the alkaline hydroxide solutions was added to the pyrolysis oil sample in a 1 :1 ratio, and each of the resulting mixtures was continuously mixed in the reaction vessel operated at 225 °C. After an hour, the mixture of the pyrolysis oil and the aqueous alkaline hydroxide solution was allowed to separate into an upgraded pyrolysis oil fraction and an aqueous fraction. About 30% of the pyrolysis oil sample was recovered as the upgraded pyrolysis oil fraction, in the instance when the 10 wt.% sodium hydroxide solution was used. About 20% of the pyrolysis oil sample was recovered as the upgraded pyrolysis oil fraction, in the instance when the 30 wt.% sodium hydroxide solution was used. The silicon and chloride content in the upgraded pyrolysis oil fraction were evaluated by inductively coupled plasma mass spectroscopy and the analytical method prescribed in UOP 779-08 for determining chloride in liquid hydrocarbons, respectively. The silicon content in each of the mixtures decreased by 50% and the chloride content decreased by about 97%.

Example 3

[0043] Three pyrolysis oil samples were prepared. The first sample was undistilled pyrolysis oil, while the second sample was the naphtha fraction and the third sample was the diesel fraction. The first sample had a silicon content of 220 ppm and a total chloride content of 3331 ppm. The second sample had a silicon content of 370 ppm and a total chloride content of 9020 ppm. The third sample had a silicon content of 230 ppm and a total chloride content of 2310 ppm. An alkaline hydroxide solution containing approximately 5 wt.% of sodium hydroxide in water was prepared. This 5% alkaline hydroxide solution was added to the first sample in a 1 : 5 ratio. The 5% alkaline hydroxide solution was added to the second sample in a 1:20 ratio. This 5% alkaline hydroxide solution was added to the third sample in a 1 :5 ratio. Each of the resulting mixtures was maintained in the reaction vessel operated at 25 °C. After ten minutes, the mixture of the pyrolysis oil and the aqueous alkaline hydroxide solution was allowed to separate into an upgraded pyrolysis oil fraction and an aqueous fraction. The upgraded pyrolysis oil fraction was again mixed with the 5% alkaline hydroxide solution and the foregoing process was repeated twice for a total of three washes with the alkaline hydroxide solution. About 90% of the pyrolysis oil sample was recovered from each of the three samples. The silicon and chloride content in the upgraded pyrolysis oil fraction were evaluated by inductively coupled plasma mass spectroscopy and the analytical method prescribed in UOP 779-08 for determining chloride in liquid hydrocarbons, respectively. The silicon content in each of the samples decreased by about 30%. The total chloride content decreased in the first and second samples by about 88% and in the third sample by about 50%.

Example 4

[0044] A pyrolysis oil sample containing undistilled pyrolysis oil was prepared. An alkaline hydroxide solution containing approximately 5 wt.% of sodium hydroxide in water was prepared. This 5% alkaline hydroxide solution was added to this sample in a 1 : 5 ratio. The resulting mixtures was maintained in the reaction vessel operated at 20 °C. After ten minutes, the mixture of the pyrolysis oil and the aqueous alkaline hydroxide solution was allowed to separate into an upgraded pyrolysis oil fraction and an aqueous fraction. The upgraded pyrolysis oil fraction was again mixed with the 5% alkaline hydroxide solution and the foregoing process was repeated twice for a total of three washes with the alkaline hydroxide solution. About 90% of the pyrolysis oil sample was recovered from each of the three samples. The silicon and chloride content in the upgraded pyrolysis oil fraction were evaluated by inductively coupled plasma mass spectroscopy and the analytical method prescribed in UOP 779-08 for determining chloride in liquid hydrocarbons, respectively. The silicon content in each of the mixtures decreased by about 30% and the chloride content decreased by about 90%.

[0045] Other objects, features and advantages of the disclosure will become apparent from the following figures, detailed description, and examples. It should be understood, however, that the figures, detailed description, and examples, while indicating specific embodiments 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 this detailed description. In further embodiments, features from specific embodiments may be combined with features from other embodiments. For example, features from one embodiment may be combined with features from any of the other embodiments. In further embodiments, additional features may be added to the specific embodiments described herein.

Claims

Claims What is claimed is:

1. A method of treating a pyrolysis oil, the method comprising: supplying, to a reaction vessel, a pyrolysis oil containing a plurality of silicon compounds and a plurality of chloride compounds, the pyrolysis oil being a mixture of a light liquid fraction obtained from processing of raw mixed plastic waste pyrolysis oil at less than about 170 degrees centigrade (°C) and a medium liquid fraction obtained from processing of the raw mixed plastic waste pyrolysis oil from about 170 °C to about 370 °C; mixing the pyrolysis oil with an aqueous alkaline hydroxide solution in the reaction vessel operated at a temperature ranging from about 15 °C to about 225 °C, the aqueous alkaline hydroxide solution containing about 1 weight percent to about 20 weight percent of the alkaline hydroxide; allowing the mixture of the pyrolysis oil and the aqueous alkaline hydroxide solution to separate into an upgraded pyrolysis oil fraction and an aqueous fraction; the upgraded pyrolysis oil fraction containing at least about 30 weight percent less of the plurality of silicon compounds than the plurality of silicon compounds in the pyrolysis oil and at least about 50 weight percent less of the plurality of chloride compounds than the plurality of chloride compounds in the pyrolysis oil; and extracting the upgraded pyrolysis oil fraction and optionally supplying it to a hydroprocessing unit.

2. The method of Claim 1, wherein the mixture of the pyrolysis oil and the aqueous alkaline hydroxide solution is separated into the upgraded pyrolysis oil fraction and the aqueous fraction by settling or coalescence.

3. The method of Claim 1, wherein the aqueous alkaline hydroxide solution contains less than about 10 weight percent of the alkaline hydroxide.

4. The method of Claim 3, wherein the upgraded pyrolysis oil fraction contains at least about 50 weight percent less of the plurality of silicon compounds than the plurality of silicon compounds in the pyrolysis oil and at least about 90 weight percent less of the plurality of chloride compounds than the plurality of chloride compounds in the pyrolysis oil. A method of treating a pyrolysis oil, the method comprising: supplying, to a reaction vessel, a pyrolysis oil containing a plurality of silicon compounds and a plurality of chloride compounds; mixing the pyrolysis oil with a first aqueous alkaline hydroxide solution in the reaction vessel operated at a temperature ranging from about 15 °C to about 30 °C, the first aqueous alkaline hydroxide solution having a pH of about 10 or greater; allowing the mixture of the pyrolysis oil and the first aqueous alkaline hydroxide solution to separate into a first upgraded pyrolysis oil fraction and a first aqueous fraction; removing the first aqueous fraction from the reaction vessel; mixing the first upgraded pyrolysis oil fraction and a second aqueous alkaline hydroxide solution in the reaction vessel operated at a temperature ranging from about 15 °C to 225 °C, the second aqueous alkaline hydroxide solution having a pH of about 10 or greater; allowing the mixture of the first upgraded pyrolysis oil fraction and the second aqueous alkaline hydroxide solution to separate into a second upgraded pyrolysis oil fraction and a second aqueous fraction; removing the second aqueous fraction from the reaction vessel; mixing the second upgraded pyrolysis oil fraction with a third aqueous alkaline hydroxide solution in the reaction vessel operated at a temperature ranging from about 15 °C to 30 °C, the third aqueous alkaline hydroxide solution having a pH of about 10 or greater; allowing the mixture of the second upgraded pyrolysis oil fraction and the third aqueous alkaline hydroxide solution to separate into a third upgraded pyrolysis oil fraction and a third aqueous fraction, the third upgraded pyrolysis oil fraction containing at least about 30 weight percent less of the plurality of silicon compounds than the plurality of silicon compounds in the pyrolysis oil and at least about 50 weight percent less of the plurality of chloride compounds than the plurality of chloride compounds in the pyrolysis oil; and extracting the third upgraded pyrolysis oil fraction and optionally supplying it to a hydroprocessing unit. The method of Claim 5, wherein the pyrolysis oil is a raw mixed plastic waste pyrolysis oil. The method of Claim 6, wherein the third upgraded pyrolysis oil fraction contains at least about 90 weight percent less of the plurality of chloride compounds than the plurality of chloride compounds in the raw mixed plastic waste pyrolysis oil. The method of Claim 5, wherein the pyrolysis oil is a light liquid fraction obtained from processing of raw mixed plastic waste pyrolysis oil at less than about 170 °C, defining a naphtha fraction. The method of Claim 8, wherein the third upgraded pyrolysis oil fraction contains at least about 80 weight percent less of the plurality of chloride compounds than the plurality of chloride compounds in the naphtha fraction. The method of Claim 5, wherein the pyrolysis oil is a medium liquid fraction obtained from processing of raw mixed plastic waste pyrolysis oil from about 170 °C to about 370 °C, defining a diesel fraction. The method of Claim 10, wherein the third upgraded pyrolysis oil fraction contains at least about 50 weight percent less of the plurality of chloride compounds than the plurality of chloride compounds in the diesel fraction. A system for treating a pyrolysis oil, the system comprising: a reaction vessel operated at a temperature ranging from about 15 °C to about 30 °C and containing:

(i) a pyrolysis oil inlet configured to receive and supply to the reaction vessel a pyrolysis oil containing a plurality of silicon compounds and a plurality of chloride compounds,

(ii) an alkaline hydroxide inlet configured to receive and supply to the reaction vessel an aqueous alkaline hydroxide solution containing less than about 20 weight percent of the alkaline hydroxide, (iii) a mixing element located inside the reaction vessel to facilitate mixing of the pyrolysis oil and the aqueous alkaline hydroxide solution,

(iv) an upgraded pyrolysis oil outlet configured to discharge an upgraded pyrolysis oil fraction that is produced by separation of the mixture of the pyrolysis oil and the aqueous alkaline hydroxide solution into the upgraded pyrolysis oil fraction and an aqueous fraction, the upgraded pyrolysis oil fraction containing at least about 30 weight percent less of the plurality of silicon compounds than the plurality of silicon compounds in the pyrolysis oil and at least about 50 weight percent less of the plurality of chloride compounds than the plurality of chloride compounds in the pyrolysis oil, and

(v) an effluent outlet configured to supply the aqueous fraction to an alkaline hydroxide recycling unit and to discharge any solids formed during production of the upgraded pyrolysis oil fraction and the aqueous fraction; and the alkaline hydroxide recycling unit connected to and in fluid communication with the effluent outlet and configured to process the aqueous fraction and supply fresh aqueous alkaline hydroxide solution to the reaction vessel. The system of Claim 12, further comprising a jacket heater operatively connected to an external wall of the reaction vessel. The system of Claim 12, further comprising a hydrotreater unit connected to and in fluid communication with the upgraded pyrolysis oil outlet of the reaction vessel. The system of Claim 12, wherein the pyrolysis oil is raw mixed plastic waste pyrolysis oil. The system of Claim 15, wherein the upgraded pyrolysis oil fraction contains at least about 90 weight percent less of the plurality of chloride compounds than the plurality of chloride compounds in the raw mixed plastic waste pyrolysis oil. The system of Claim 12, wherein the pyrolysis oil is a light liquid fraction obtained from processing of raw mixed plastic waste pyrolysis oil at less than about 170 °C, defining a naphtha fraction. The system of Claim 17, wherein the upgraded pyrolysis oil fraction contains at least about 80 weight percent less of the plurality of chloride compounds than the plurality of chloride compounds in the naphtha fraction. The system of Claim 12, wherein the pyrolysis oil is a medium liquid fraction obtained from processing of raw mixed plastic waste pyrolysis oil from about 170 °C to about 370 °C, defining a diesel fraction. The system of Claim 19, wherein the third upgraded pyrolysis oil fraction contains at least about 50 weight percent less of the plurality of chloride compounds than the plurality of chloride compounds in the diesel fraction.