Two-stage catalytic method for upgrading mixed pyrolysis oil into BTEX

Abstract

In accordance with one or more embodiments of the present disclosure, a multi-stage process for upgrading a mixed pyrolysis oil comprising a polyaromatic compound to benzene, toluene, ethylbenzene, and xylene (BTEX) includes combining a light pyrolysis oil with a heavy pyrolysis oil to form a mixed pyrolysis oil; upgrading the mixed pyrolysis oil in a slurry reactor zone to produce an intermediate product wherein the slurry reactor zone comprises a mixed metal oxide catalyst; and hydrocracking the intermediate product in a fixed bed reactor zone to produce BTEX wherein the fixed bed reactor zone comprises a mesoporous zeolite supported metal catalyst.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to U.S. Application No. 18 / 046,034, filed on October 12, 2022, which is incorporated herein by reference in its entirety. Technical Field

[0003] Embodiments of the present disclosure relate generally to petroleum products, and more particularly to a method for upgrading mixed pyrolysis oil. Background Art

[0004] In a typical hydrocarbon thermal cracking process, a stream called pyrolysis oil is discharged from the steam cracker as the bottom layer. Depending on the steam cracker feed, pyrolysis oil varies from heavy liquid to light liquid. There are two main sources of pyrolysis oil: heavy pyrolysis oil discharged from a naphtha steam cracker; and light pyrolysis oil discharged from a gas stream cracker.

[0005] Both heavy and light pyrolysis oils are low in sulfur but rich in aromatic compounds. While these properties may make pyrolysis oil a desirable feedstock for subsequent chemical conversions, traditional methods for upgrading pyrolysis oil are complex and inefficient. Summary of the invention

[0006] Heavy pyrolysis oil and light pyrolysis oil are both usually burned as fuel and are not considered to have high value. However, due to the high amount of aromatic compounds, relatively cheap pyrolysis oil will be an ideal feedstock for producing valuable intermediate petrochemicals such as benzene, toluene, ethylbenzene and xylene (BTEX). BTEX can then be processed to maximize p-xylene, which is a key base material for producing purified terephthalic acid (PTA) and final polyester. Therefore, there is a continuous demand for simplified and more effective novel pyrolysis oil upgrading methods. Embodiments of the present disclosure relate to such methods.

[0007] According to one embodiment, a multistage process for upgrading a mixed pyrolysis oil containing polyaromatic compounds to benzene, toluene, ethylbenzene and xylenes (BTEX) is provided. The process comprises combining a light pyrolysis oil with a heavy pyrolysis oil to form a mixed pyrolysis oil; upgrading the mixed pyrolysis oil in a slurry reactor zone to produce an intermediate product, wherein the slurry reactor zone comprises a mixed metal oxide catalyst; and hydrocracking the intermediate product in a fixed bed reactor zone to produce BTEX, wherein the fixed bed reactor zone comprises a medium pore zeolite supported metal catalyst.

[0008] Additional features and advantages of the embodiments described herein will be set forth in the detailed description that follows, and in part will be readily understood by those skilled in the art from that description or learned by practicing the described embodiments, including the detailed description provided below and the claims.

[0009] BRIEF DESCRIPTION OF THE DRAWINGS

[0010] The following detailed description of specific embodiments of the present disclosure may be best understood when read in conjunction with the following drawings, in which:

[0011] Figure 1 is a diagrammatic view of a system for producing BTEX from a mixed pyrolysis oil feed according to an embodiment disclosed herein;

[0012] Figure 2 is a schematic representation of cascade reactions that may occur in a slurry reactor zone according to embodiments described herein; and

[0013] Figure 3 is a schematic representation of a cascade of reactions that may occur in a fixed bed reactor zone according to embodiments described herein. DETAILED DESCRIPTION

[0014] As used herein, the term "light pyrolysis oil" refers to a stream whose composition is equal to the stream leaving the bottom layer of a gas steam cracker. In some embodiments, all or part of the stream leaving the bottom layer of the gas steam cracker may be further processed. In some embodiments, the stream leaving the bottom layer of the gas steam cracker may be further processed and separated at a hydrogenation unit to produce one or more processed streams. In some embodiments, the initial boiling point of the light pyrolysis oil is 30°C to 150°C, 40°C to 120°C, 40°C to 100°C, 40°C to 90°C, 50°C to 90°C, 60°C to 90°C, 70°C to 90°C, 75°C to 85°C, or 75°C to 80°C. According to one or more embodiments, the final boiling point of the light pyrolysis oil is 120°C to 450°C, 150°C to 450°C, 200°C to 450°C, 250°C to 450°C, 200°C to 450°C, 250°C to 450°C, 300°C to 400°C, or 325°C to 375°C. According to one or more embodiments, the light pyrolysis oil comprises paraffins, BTEX, mono-aromatics, naphthalene, indene, monocycloalkanes and dicyclopentadiene (DCPD). In some embodiments, the light pyrolysis oil does not comprise polyaromatic compounds as defined herein. According to one or more embodiments, the light pyrolysis oil comprises paraffins at a concentration of 1% to 30% by weight, 1% to 20% by weight, 2% to 20% by weight, 2% to 15% by weight, 3% to 15% by weight, 5% to 15% by weight or 5% to 10% by weight. In some embodiments, the light pyrolysis oil comprises BTEX at a concentration of 1 wt % to 20 wt %, 1 wt % to 15 wt %, 2 wt % to 15 wt %, 1 wt % to 10 wt %, 2 wt % to 10 wt %, 2 wt % to 8 wt %, 2 wt % to 6 wt % or 2 wt % to 5 wt %. According to an embodiment, the light pyrolysis oil comprises monoaromatics at a concentration of 10 wt % to 90 wt %, 15 wt % to 90 wt %, 20 wt % to 90 wt %, 20 wt % to 85 wt %, 25 wt % to 85 wt %, 30 wt % to 85 wt %, 35 wt % to 85 wt %, 40 wt % to 85 wt %, 40 wt % to 80 wt %, 45 wt % to 75 wt %, 50 wt % to 70 wt % or 55 wt % to 65 wt %. In some embodiments, the light pyrolysis oil comprises naphthalene at a concentration of 1 wt % to 15 wt %, 2 wt % to 15 wt %, 1 wt % to 10 wt %, 2 wt % to 10 wt %, 1 wt % to 8 wt %, 1 wt % to 6 wt %, 2 wt % to 6 wt %, or 2 wt % to 5 wt %.According to one or more embodiments, the light pyrolysis oil comprises indene at a concentration of 1 wt % to 30 wt %, 1 wt % to 20 wt %, 2 wt % to 20 wt %, 2 wt % to 15 wt %, 5 wt % to 15 wt %, or 8 wt % to 12 wt %. In some embodiments, the light pyrolysis oil comprises monocyclic alkanes at a concentration of 1 wt % to 15 wt %, 2 wt % to 15 wt %, 1 wt % to 10 wt %, 2 wt % to 10 wt %, 1 wt % to 8 wt %, 1 wt % to 6 wt %, 2 wt % to 6 wt %, or 2 wt % to 5 wt %. According to one or more embodiments, the light pyrolysis oil comprises a concentration of 1 wt % to 60 wt %, 1 wt % to 50 wt %, 1 wt % to 40 wt %, 1 wt % to 30 wt %, 1 wt % to 20 wt %, 2 wt % to 20 wt %, 2 wt % to 15 wt %, 5 wt % to 15 wt % or 8 wt % to 12 wt % DCPD. In some embodiments, the light pyrolysis oil comprises 3 wt % to 15 wt % paraffins, 2 wt % to 8 wt % BTEX, 40 wt % to 80 wt % monoaromatics, 1 wt % to 6 wt % naphthalene, 5 wt % to 15 wt % indene, 1 wt % to 6 wt % monocycloalkanes and 5 wt % to 15 wt % DCPD.

[0015] As used herein, the term "heavy pyrolysis oil" refers to a stream whose composition is equal to the stream leaving the bottom layer of a naphtha steam cracking unit. In some embodiments, all or part of the stream leaving the bottom layer of a naphtha steam cracking unit may be further processed. In some embodiments, the stream leaving the bottom layer of a naphtha steam cracking unit may be further processed and separated at a hydrogenation unit to produce one or more processed streams. In some embodiments, the initial boiling point of the heavy pyrolysis oil is 90°C to 250°C, 100°C to 200°C, 110°C to 190°C, 120°C to 180°C, 130°C to 170°C, or 140°C to 160°C. According to one or more embodiments, the final boiling point of the heavy pyrolysis oil is 500°C to 950°C, 500°C to 900°C, 550°C to 850°C, 600°C to 800°C, 650°C to 750°C, or 700°C to 750°C. In some embodiments, heavy pyrolysis oil comprises monoaromatics, diaromatics, triaromatics, tetraaromatics, pentaaromatics, hexaaromatics and heptaaromatics and larger aromatics. According to one or more embodiments, heavy pyrolysis oil comprises monoaromatics at a concentration of 1 wt % to 50 wt %, 1 wt % to 40 wt %, 2 wt % to 40 wt %, 5 wt % to 40 wt %, 5 wt % to 35 wt %, 5 wt % to 30 wt %, 10 wt % to 30 wt %, 10 wt % to 25 wt %, 15 wt % to 25 wt % or 15 wt % to 20 wt %. In some embodiments, the heavy pyrolysis oil comprises diaromatic hydrocarbons in a concentration of 2 wt % to 50 wt %, 5 wt % to 50 wt %, 5 wt % to 45 wt %, 10 wt % to 40 wt %, 15 wt % to 45 wt %, 20 wt % to 40 wt %, 20 wt % to 35 wt %, 25 wt % to 35 wt % or 25 wt % to 30 wt %. According to one or more embodiments, the heavy pyrolysis oil comprises triaromatic hydrocarbons in a concentration of 1 wt % to 20 wt %, 1 wt % to 15 wt %, 2 wt % to 15 wt %, 1 wt % to 10 wt %, 2 wt % to 10 wt %, 2 wt % to 8 wt %, 3 wt % to 7 wt % or 4 wt % to 6 wt %. In some embodiments, the heavy pyrolysis oil comprises tetraaromatics at a concentration of 1 wt % to 20 wt %, 1 wt % to 15 wt %, 2 wt % to 15 wt %, 1 wt % to 10 wt %, 2 wt % to 10 wt %, 2 wt % to 8 wt %, 3 wt % to 7 wt % or 4 wt % to 6 wt %. According to one or more embodiments, the heavy pyrolysis oil comprises pentaaromatics at a concentration of 1 wt % to 30 wt %, 1 wt % to 20 wt %, 2 wt % to 20 wt %, 2 wt % to 15 wt %, 5 wt % to 15 wt %, 8 wt % to 12 wt % or 8 wt % to 10 wt %.In some embodiments, the heavy pyrolysis oil comprises hexaaromatics in a concentration of 1 wt % to 30 wt %, 1 wt % to 20 wt %, 2 wt % to 20 wt %, 2 wt % to 15 wt %, 5 wt % to 15 wt % or 8 wt % to 12 wt %. According to one or more embodiments, the heavy pyrolysis oil comprises heptaaromatics and larger aromatics in a concentration of 2 wt % to 50 wt %, 5 wt % to 50 wt %, 5 wt % to 45 wt %, 10 wt % to 40 wt %, 15 wt % to 45 wt %, 15 wt % to 40 wt %, 15 wt % to 35 wt %, 15 wt % to 30 wt %, 20 wt % to 30 wt % or 20 wt % to 25 wt %. In some embodiments, the heavy pyrolysis oil comprises 10 wt % to 30 wt % monoaromatics, 15 wt % to 45 wt % diaromatics, 2 wt % to 10 wt % triaromatics, 2 wt % to 10 wt % tetraaromatics, 5 wt % to 15 wt % pentaaromatics, 5 wt % to 15 wt % hexaaromatics, and 10 wt % to 40 wt % heptaaromatics and larger aromatics.

[0016] As used herein, the term "hydrocarbon oil" or "hydrocarbon feedstock" refers to an oily liquid consisting primarily of a mixture of hydrocarbon compounds. Hydrocarbon oils may include refined oils obtained from crude oil, synthetic crude oil, asphalt, oil sands, shale oil, or kerosene. The term "refined oil" includes, but is not limited to: vacuum gas oil (VGO), depolyaromatized oil (DAO), or demetallized oil (DMO) obtained from a depolyaromatization process; light and / or heavy coker gas oils obtained from a coking process; cycle oils obtained from an FCC process; and gas oils obtained from a visbreaking process.

[0017] As used herein, the term "hydrocarbon" refers to a compound composed entirely of carbon and hydrogen atoms. x -C y The expression "hydrocarbon" refers to hydrocarbons having x to y carbon atoms. For example, C1-C5 hydrocarbons include methane, ethane, propane, butane, and pentane.

[0018] As used herein, the term "polyaromatics" refers to compounds composed of three or more aromatic rings.

[0019] As used herein, the term "naphtheno / olefino-benz" refers to a compound having a naphthyl structure having one or more olefin branches, cyclo-paraffin branches, or a combination thereof.

[0020] As used herein, the term "heptaarenes and larger" refers to polyaromatic hydrocarbons having seven or more aromatic rings.

[0021] As used herein, the term "hydrogen / oil ratio" or "hydrogen-oil ratio" or "hydrogen-hydrocarbon ratio" refers to a standard measure of the volume ratio of hydrogen gas circulating through a reactor relative to the volume of feed. The hydrogen / oil ratio can be determined by comparing the flow volume of the hydrogen gas stream to the flow volume of the hydrocarbon feed.

[0022] As used herein, the term "liquid hourly space velocity" or "LHSV" refers to the ratio of the liquid flow rate of the hydrocarbon feed to the volume of the catalyst.

[0023] As used herein, the term "conduit" includes casings, liners, pipes, tubing, coils, and mechanical structures having an internal void.

[0024] As used herein, the term "amount decreased" of a substance means that the concentration of the substance before passing through a stage of the process under examination is greater than its concentration after passing through the stage. As used herein, the term "amount increased" of a substance means that the concentration of the substance after passing through a stage of the process under examination is greater than its concentration before passing through the stage.

[0025] As used throughout this disclosure, "zeolite" may refer to a microporous inorganic material having regular intracrystalline cavities and channels of molecular size. Zeolites generally contain a crystalline structure, rather than an amorphous structure, such as an amorphous structure that can be observed in some porous materials (such as amorphous silica). Zeolites generally include a microporous framework, which can be identified by the framework type. The microporous structure of the zeolite (e.g., a pore size of 0.3nm to 2nm) can provide a large surface area and a desired size / shape selectivity, which can be beneficial to catalysis. The zeolite may include, for example, an aluminosilicate, a titanosilicate, or a pure silicate. In an embodiment, the zeolite may include micropores (present in the microstructure of the zeolite) and also include mesopores. As used throughout this disclosure, micropores refer to holes in the structure having a diameter greater than or equal to 0.1nm and less than or equal to 2nm, and mesopores refer to holes in the structure having a diameter greater than or equal to 2nm and less than or equal to 50nm. Unless otherwise specified herein, the "pore size" of a material refers to the average pore size, but the material may also include micropores and / or mesopores having a specific size that is different from the average pore size.

[0026] According to one aspect, a multistage method is provided for upgrading a mixed pyrolysis oil containing polyaromatic compounds to benzene, toluene, ethylbenzene and xylene (BTEX). The method comprises merging a light pyrolysis oil with a heavy pyrolysis oil to form a mixed pyrolysis oil. It is not intended to be limited to any particular theory, but it is believed that, compared with a separate heavy pyrolysis oil, merging the heavy pyrolysis oil with the light pyrolysis oil provides a mixed pyrolysis oil with increased mobility, so that the mixed pyrolysis oil can have better contact with a mixed metal oxide catalyst than a separate heavy pyrolysis oil. In addition, the components of both the light pyrolysis oil and the heavy pyrolysis oil can be fruitfully converted into BTEX in the process. Therefore, the light pyrolysis oil can be advantageously used as a diluent for the heavy pyrolysis oil, and in addition to the heavy pyrolysis oil, the components of the light pyrolysis oil can also be upgraded to BTEX in a multistage method. In some embodiments, it is 5 wt % to 50 wt %, 5 wt % to 45 wt %, 5 wt % to 40 wt %, 10 wt % to 40 wt %, 10 wt % to 35 wt %, 10 wt % to 30 wt % or 15 wt % to 25 wt % light pyrolysis oil that described mixed pyrolysis oil comprises concentration.According to one or more embodiments, it is 50 wt % to 95 wt %, 55 wt % to 95 wt %, 60 wt % to 95 wt %, 65 wt % to 95 wt %, 65 wt % to 90 wt %, 70 wt % to 90 wt % or 75 wt % to 90 wt % heavy pyrolysis oil that described mixed pyrolysis oil comprises concentration.In some embodiments, described mixed pyrolysis oil comprises 5 wt % to 40 wt % light pyrolysis oil and 60 wt % to 95 wt % heavy pyrolysis oil.

[0027] The process may further include upgrading the mixed pyrolysis oil in a slurry reactor zone to produce an intermediate product, and hydrocracking the intermediate product in a fixed bed reactor zone to produce BTEX. Although the presently described process is not limited to any particular apparatus, Figure 1 Schematic diagrams of systems suitable for performing embodiments of the methods described herein are provided.

[0028] Reference Figure 1 , the upgrading system 10 includes a first reactor 12 and a second reactor 14. In an embodiment, the first reactor 12 may be a slurry reactor (e.g., a fluidized bed slurry reactor), and the second reactor 14 may be a fixed bed reactor. In an embodiment, the catalyst recovery unit may be a heated liquid-solid separator.

[0029] In operation, heavy pyrolysis oil 15 and light pyrolysis oil 16 can be combined to produce mixed pyrolysis oil feed 17. Heavy pyrolysis oil 15 can be discharged from naphtha steam cracking unit (not shown) as bottom fraction. Light pyrolysis oil 16 can be discharged from gas cracking unit (not shown) as bottom fraction. Mixed pyrolysis oil feed 17 can be added to first reactor 12. First reactor 12 can include mixed metal oxide catalyst, which will be described in more detail below. While adding hydrogen to first reactor 12, mixed pyrolysis oil can be contacted with mixed metal oxide catalyst. In an embodiment, mixed metal oxide catalyst can be added simultaneously with mixed pyrolysis oil feed 17 so that liquid phase and solid phase can be mixed to produce slurry of slurry reactor. After allowing reaction, whole slurry can be transferred to separator 18 via conduit 19, and separator 18 is used to separate gaseous product, liquid product and spent catalyst (solid). The gaseous products can be collected through vent 20, the liquid products can be delivered to the second reactor 14 via conduit 22, and the solids can be delivered to the catalyst recovery unit 24 via conduit 25. In the catalyst recovery unit 24, the catalyst is separated from the residual polyaromatics and other heavy residues. The catalyst can be collected through conduit 26, and the residue can be recycled back to the mixed pyrolysis oil feed 17 via conduit 27. The collected catalyst can be recovered and recycled back to the first reactor 12.

[0030] As described above, the second reactor 14 can be a fixed bed reactor and can contain a mesoporous zeolite-supported metal catalyst, which will be described in more detail below. While adding hydrogen to the second reactor 14, the liquid product from the first reactor 12 can be contacted with the mesoporous zeolite-supported metal catalyst. Optionally, before contacting with the mesoporous zeolite-supported metal catalyst, the liquid product from the separator 18 can be sent through the heat exchanger 28 and then enter the second reactor 14 via the conduit 30, such as Figure 1 . After being allowed to react, the resulting gaseous products can be separated from the liquid products in separator 32 and then discharged via conduit 34 or analyzed by, for example, gas chromatograph 36. The liquid products can be collected in collector 38. In an embodiment, the liquid products can be sent through a heat exchanger (not shown) for cooling and then collected in collector 38. Various means of controlling flow rates, such as valves and pumps 40, can be used where needed throughout the system.

[0031] Having described embodiments of a system for performing a multi-stage process to upgrade a mixed pyrolysis oil, embodiments of the process will now be described.

[0032] In an embodiment, the mixed pyrolysis oil, hydrogen, and mixed metal oxide catalyst are added to a slurry reactor. In some embodiments, the components can be added simultaneously, or in other embodiments, the components can be added at different times. The reactor can be agitated. In an embodiment, agitation can include stirring. In other embodiments. Agitation can include shaking. In an embodiment, the reactor can be agitated by stirring and shaking.

[0033] The mixed pyrolysis oil is contacted with a mixed metal oxide catalyst in a slurry reactor zone to produce diaromatic intermediates by successive selective hydrogenation, selective saturated ring opening, hydrodealkylation, trans-alkylation and disproportionation, resulting in polyaromatic cracking (described more fully below). Figure 2 An example of such a reaction in a cascade is shown in , starting with pyrene to produce methylated naphthalene. Of course, the formation of methylated naphthalene from pyrene is only one example of a cascade reaction, and other starting materials and products are also contemplated.

[0034] In an embodiment, the mixed pyrolysis oil may include one or more polyaromatic compounds. The polyaromatic compound may include 16 or more aromatic carbon atoms (C 16+ ), such as C 16 -C 110 Polyaromatic compounds. For example, the polyaromatic compound may be C 16 -C 100 , C 16 -C 90 , C 16 -C 80 , C 16 -C 70 , C 16 -C 60 , C 16 -C 50 , C 16 -C 40 , C 16 -C 30 , C 16 -C 20 , C 20 -C 110 , C 30 -C 110 , C 40 -C 110 , C 50 -C 110 , C 60 -C 110 , C 70 -C 110 , C 80 -C 110 , C 90 -C110 or even C 100 -C 110 Polyaromatic Compounds. In an embodiment, the polyaromatic compound may include a plurality of fused aromatic rings, such as 3, 4, 5, 6, 7, 8, 9, or 10 fused benzene rings.

[0035] According to one or more embodiments, mixed pyrolysis oil comprises dicyclopentadiene (DCPD).In some embodiments, mixed pyrolysis oil comprises the DCPD that concentration is 0.1 wt % to 50 wt %, 0.1 wt % to 20 wt %, 0.2 wt % to 10 wt %, 0.2 wt % to 5 wt %, 0.5 wt % to 5 wt %, 0.5 wt % to 4 wt % or 1 wt % to 3 wt %.In some embodiments, DCPD consumption can be monitored to assess catalyst activity.

[0036] The conditions of the reactor (such as the flow velocity entering the reactor, the temperature in the reactor and the pressure in the reactor) can be changed to control the reaction in the first reactor. In an embodiment, the flow velocity of hydrogen can be 15ml / min to 35ml / min, such as 20ml / min to 35ml / min, 25ml / min to 35ml / min, 30ml / min to 35mL / min, 15ml / min to 30ml / min, 15ml / min to 25ml / min or even 15ml / min to 20ml / min. It is conceivable that the flow velocity of hydrogen can be from any lower limit disclosed herein to any upper limit disclosed herein. It is not intended to be limited to any particular theory, it is believed that the hydrogen flow rate entering the reactor may not allow enough levels of hydrogen to enter the reactor less than 15ml / min. However, the hydrogen flow rate greater than 35ml / min may cause too much hydrogen to circulate in the system, thereby consuming the hydrogen of unacceptable amount.

[0037] In an embodiment, the pyrolysis oil, diluent, hydrogen and mixed metal oxide catalyst are allowed to stay in the slurry reactor for a period of 1.5 h to 7.5 h. For example, the components may be allowed to stay in the slurry reactor for 1.5 h to 7 h, 1.5 h to 6.5 h, 1.5 h to 6 h, 1.5 h to 5.5 h, 1.5 h to 5 h, 1.5 h to 4.5 h, 1.5 h to 4 h, 1.5 h to 3.5 h, 1.5 h to 3 h, 1.5 h to 2.5 h, 1.5 h to 2 h, 2 h to 7.5 h, 2.5 h to 7.5 h, 3 h to 7.5 h, 3.5 h to 7.5 h, 4 h to 7.5 h, 4.5 h to 7.5 h, 5 h to 7.5 h, 5.5 h to 7.5 h, 6 h to 7.5 h, 6.5 h to 7.5 h, or even 7 h to 7.5 h. It is contemplated that the flow rate of the pyrolysis oil and diluent may be from any lower limit disclosed herein to any upper limit disclosed herein. Without intending to be limited to any particular theory, it is believed that if the components are allowed to stay in the slurry reactor for less than 1.5 hours, one or more of the continuous selective hydrogenation, selective opening of saturated rings, hydrodealkylation, transalkylation and disproportionation may not have enough time to complete. However, if this time is extended beyond 7.5 hours, unwanted by-products may be produced.

[0038] In an embodiment, the first reactor in the slurry reactor zone may be operated at a temperature of 350° C. to 450° C., such as 360° C. to 450° C., 370° C. to 450° C., 380° C. to 450° C., 390° C. to 450° C., 400° C. to 450° C., 410° C. to 450° C., 420° C. to 450° C., 430° C. to 450° C., 440° C. to 450° C., 350° C. to 440° C., 350° C. to 430° C., 350° C. to 420° C., 350° C. to 410° C., 350° C. to 400° C., 350° C. to 390° C., 350° C. to 380° C., 350° C. to 370° C., or even 350° C. to 360° C. It is contemplated that the temperature may be from any lower limit disclosed herein to any upper limit disclosed herein. Without intending to be bound by any particular theory, it is believed that reactor temperatures below 350°C may cause one or more of the sequential selective hydrogenation, selective opening of saturated rings, hydrodealkylation, transalkylation, and disproportionation to proceed too slowly to be commercially viable, while reactor temperatures above 450°C may cause one or more of these reactions to proceed too rapidly, which may result in runaway reactions or premature catalyst deactivation.

[0039] In an embodiment, the first reactor of the slurry reactor zone may be operated at a pressure of 3 MPa to 18 MPa, 3.5 MPa to 18 MPa, 4 MPa to 18 MPa, 4.5 MPa to 18 MPa, 5 MPa to 18 MPa, 5.5 MPa to 18 MPa, 6 MPa to 18 MPa, 6.5 MPa to 18 MPa, 7 MPa to 18 MPa, 7.5 MPa to 18 MPa, 8 MPa to 18 MPa, 8.5 MPa to 18MPa, 9MPa to 18MPa, 9.5MPa to 18MPa, 10MPa to 18MPa, 10.5MPa to 18MPa, 11MPa to 18MPa, 11.5MPa to 18MPa, 12MPa to 18MPa, 12.5MPa to 18MPa, 13MPa to 18MPa, 13.5MPa to 18MPa, 14MPa to 18MPa, 14.5MPa to 18MPa, 15MPa to 1 8MPa, 15.5MPa to 18MPa, 16MPa to 18MPa, 3MPa to 17.5MPa, 3MPa to 17MPa, 3MPa to 16.5MPa, 3MPa to 16MPa, 3MPa to 15.5MPa, 3MPa to 15MPa, 3MPa to 14.5MPa, 3MPa to 14MPa, 3MPa to 13.5MPa, 3MPa to 13MPa, 3MPa to 12.5MPa, 3MPa The pressure of the present invention can be from 3MPa to 12MPa, 3MPa to 11.5MPa, 3MPa to 11MPa, 3MPa to 10.5MPa, 3MPa to 10MPa, 3MPa to 9.5MPa, 3MPa to 9MPa, 3MPa to 8.5MPa, 3MPa to 8MPa, 3MPa to 7.5MPa, 3MPa to 7MPa, 3MPa to 6.5MPa, 3MPa to 6MPa, 3MPa to 5.5MPa, or even 3MPa to 5MPa. It is conceivable that the pressure can be from any lower limit disclosed herein to any upper limit disclosed herein. It is not intended to be limited to any particular theory, and it is believed that the pressure below 3MPa may not be sufficient to cause one or more of continuous selective hydrogenation, selective ring opening of saturated rings, hydrodealkylation, transalkylation and disproportionation to occur. However, at a pressure higher than 18MPa, a dedicated high-pressure device may be required, which will increase the cost of reacting.

[0040] The slurry reactor includes a mixed metal oxide catalyst. In an embodiment, the mixed metal oxide catalyst comprises two or more of Fe2O3, ZrO2, CeO2, Al2O3, TiO2, MoO3, Co2O3, and NiO. In an embodiment, the mixed metal oxide catalyst may include 50 wt % to 98 wt %, 55 wt % to 95 wt %, 60 wt % to 95 wt %, 65 wt % to 95 wt %, 65 wt % to 90 wt %, 70 wt % to 90 wt %, 75 wt % to 90 wt %, or 80 wt % to 85 wt % Fe2O3. In some embodiments, the mixed metal oxide catalyst may include 1 wt % to 60 wt %, 2 wt % to 60 wt %, 2 wt % to 50 wt %, 2 wt % to 40 wt %, 2 wt % to 30 wt %, 2 wt % to 20 wt %, 2 wt % to 15 wt %, 3 wt % to 15 wt %, 3 wt % to 10 wt %, 5 wt % to 10 wt %, or 7 wt % to 8 wt % ZrO 2. According to one or more embodiments, the mixed metal oxide catalyst may include 0.5 wt % to 10 wt %, 0.5 wt % to 7 wt %, 0.5 wt % to 5 wt %, 1 wt % to 5 wt %, 1 wt % to 4 wt %, 2 wt % to 4 wt %, or 2 wt % to 3 wt % CeO 2. In some embodiments, the mixed metal oxide catalyst may include 1 wt % to 50 wt %, 1 wt % to 40 wt %, 1 wt % to 30 wt %, 1 wt % to 20 wt %, 2 wt % to 20 wt %, 2 wt % to 15 wt %, 3 wt % to 15 wt %, 3 wt % to 12 wt %, 5 wt % to 10 wt %, or 6 wt % to 8 wt % Al2O3, wherein the wt % is calculated based on the total amount of oxides.

[0041] After the pyrolysis oil is contacted with the mixed metal oxide catalyst, a gas phase, a liquid phase and a solid phase are produced and can be separated from each other. The gas phase can be discharged or collected. Conveniently, the gas phase can be analyzed before collection or discharge, so that the material balance before and after the reaction can be calculated. The solid phase includes the used mixed metal oxide catalyst, which can be recycled to the slurry reactor. The liquid phase includes an intermediate product, which is sent to the fixed bed reactor area for further treatment. In an embodiment, the intermediate product can include diaromatic compounds and monoaromatic compounds. Examples of diaromatic compounds include but are not limited to naphthalene and tetralin, both of which can be unsubstituted or substituted by straight or branched hydrocarbon substituents. Examples of monoaromatic compounds include but are not limited to benzene, which can be unsubstituted or substituted by straight or branched hydrocarbon substituents.

[0042] In an embodiment, 90% to 100% pyrolysis oil can be converted into intermediate product.For example, 90% to 99%, 90% to 98%, 90% to 97%, 90% to 96%, 90% to 95%, 90% to 94%, 90% to 93%, 90% to 92%, 90% to 91%, 91% to 100%, 92% to 100%, 93% to 100%, 94% to 100%, 95% to 100%, 96% to 100%, 97% to 100%, 98% to 100% or even 99% to 100% pyrolysis oil can be converted into intermediate product.It is contemplated that the yield of intermediate product can be from any lower limit disclosed herein to any upper limit disclosed herein.

[0043] The liquid phase may be fed to a second reactor in the fixed bed reactor zone. In an embodiment, an optional heat exchanger may be located between the slurry reactor zone and the fixed bed reactor zone so that the temperature of the liquid phase may be controlled prior to its introduction into the fixed bed reactor. The optional heat exchanger may help control the temperature of the liquid intermediate product at a temperature sufficient to avoid condensation of the intermediate product between the slurry reactor and the fixed bed reactor.

[0044] The intermediate from the slurry reactor zone is contacted with a medium pore zeolite supported metal catalyst in a fixed bed reactor to produce BTEX by selective hydrogenation, selective ring opening of saturated rings, followed by further hydrodealkylation, transalkylation and disproportionation, as described more fully below. This cascade reaction is Figure 3 As shown, starting from naphthalene, BTEX is obtained. If excessive cracking occurs, saturated hydrocarbons may also be produced. Of course, the formation of BTEX from naphthalene is only one example of a cascade reaction, and other starting materials are also considered.

[0045] The conditions of the reactor (such as the flow rate entering the fixed bed reactor, the temperature in the reactor and the pressure in the reactor) can be changed to control the reaction in the second reactor. In an embodiment, the flow rate of hydrogen can be 15ml / min to 35ml / min, such as 20ml / min to 35ml / min, 25ml / min to 35ml / min, 30ml / min to 35mL / min, 15ml / min to 30ml / min, 15ml / min to 25ml / min, or even 15ml / min to 20ml / min. It is conceivable that the hydrogen flow rate can be from any lower limit disclosed herein to any upper limit disclosed herein. It is not intended to be limited to any particular theory, it is believed that the hydrogen flow rate entering the reactor may not allow enough levels of hydrogen to enter the reactor less than 15ml / min. However, the hydrogen flow rate greater than 35ml / min may cause too much hydrogen to circulate in the system, thereby consuming unacceptable amounts of hydrogen.

[0046] In an embodiment, the flow rate of the liquid product stream from the slurry reactor zone can be from 0.2 g / min to 1 g / min, such as 0.3 g / min to 1 g / min, 0.4 g / min to 1 g / min, 0.5 g / min to 1 g / min, 0.6 g / min to 1 g / min, 0.7 g / min to 1 g / min, 0.8 g / min to 1 g / min, 0.9 g / min to 1 g / min, 0.2 g / min to 0.9 g / min, 0.2 g / min to 0.8 g / min, 0.2 g / min to 0.7 g / min, 0.2 g / min to 0.6 g / min, 0.2 g / min to 0.5 g / min, 0.2 g / min to 0.4 g / min, or even 0.2 g / min to 0.3 g / min. It is contemplated that the flow rate of the liquid product stream from the slurry reactor zone can be from any lower limit disclosed herein to any upper limit disclosed herein. Any practical means for controlling the flow rate may be used, such as a liquid pump. Without intending to be bound by any particular theory, it is believed that a flow rate of the liquid product stream from the slurry reactor zone of less than 0.2 g / min may not allow a sufficient level of liquid product stream to enter the reactor. However, a flow rate greater than 1 g / min may result in too much liquid product stream circulating in the system, leaving an unacceptable amount of liquid product stream unreacted when leaving the reactor.

[0047] In an embodiment, the second reactor in the fixed bed reactor zone may be operated at a temperature of 350°C to 450°C, such as 360°C to 450°C, 370°C to 450°C, 380°C to 450°C, 390°C to 450°C, 400°C to 450°C, 410°C to 450°C, 420°C to 450°C, 430°C to 450°C, 440°C to 450°C, 350°C to 440°C, 350°C to 430°C, 350°C to 420°C, 350°C to 410°C, 350°C to 400°C, 350°C to 390°C, 350°C to 380°C, 350°C to 370°C, or even 350°C to 360°C. It is contemplated that the temperature may be from any lower limit disclosed herein to any upper limit disclosed herein. The temperature within the fixed bed reactor may, but need not be, the same as the temperature within the slurry reactor. Without intending to be bound by any particular theory, it is believed that reactor temperatures below 350°C may cause one or more of the selective hydrogenation, selective opening of saturated rings followed by further hydrodealkylation, transalkylation, and disproportionation to proceed too slowly to be commercially viable, while reactor temperatures above 450°C may cause one or more of these reactions to proceed too rapidly, which may result in a runaway reaction or premature catalyst deactivation.

[0048] In an embodiment, the second reactor in the fixed bed reactor zone may be operated at a pressure of 3 MPa to 18 MPa, 3.5 MPa to 18 MPa, 4 MPa to 18 MPa, 4.5 MPa to 18 MPa, 5 MPa to 18 MPa, 5.5 MPa to 18 MPa, 6 MPa to 18 MPa, 6.5 MPa to 18 MPa, 7 MPa to 18 MPa, 7.5 MPa to 18 MPa, 8 MPa to 18 MPa, 8.5 MPa to 18 MPa. a to 18MPa, 9MPa to 18MPa, 9.5MPa to 18MPa, 10MPa to 18MPa, 10.5MPa to 18MPa, 11MPa to 18MPa, 11.5MPa to 18MPa, 12MPa to 18MPa, 12.5MPa to 18MPa, 13MPa to 18MPa, 13.5MPa to 18MPa, 14MPa to 18MPa, 14.5MPa to 18MPa, 15MPa to 18MPa, 15.5MPa to 18MPa, 16MPa to 18MPa, 3MPa to 17.5MPa, 3MPa to 17MPa, 3MPa to 16.5MPa, 3MPa to 16MPa, 3MPa to 15.5MPa, 3MPa to 15MPa, 3MPa to 14.5MPa, 3MPa to 14MPa, 3MPa to 13.5MPa, 3MPa to 13MPa, 3MPa to 12.5MPa, 3MP The pressure in the fixed bed reactor can be from 3MPa to 12MPa, 3MPa to 11.5MPa, 3MPa to 11MPa, 3MPa to 10.5MPa, 3MPa to 10MPa, 3MPa to 9.5MPa, 3MPa to 9MPa, 3MPa to 8.5MPa, 3MPa to 8MPa, 3MPa to 7.5MPa, 3MPa to 7MPa, 3MPa to 6.5MPa, 3MPa to 6MPa, 3MPa to 5.5MPa, or even 3MPa to 5MPa. It is conceivable that the pressure can be from any lower limit disclosed herein to any upper limit disclosed herein. The pressure in the fixed bed reactor can be but need not be the same as the pressure in the slurry reactor. It is not intended to be limited to any particular theory, it is believed that the pressure below 3MPa may not be sufficient to cause selective hydrogenation, selective ring opening of saturated rings, then further hydrodealkylation, transalkylation and disproportionation to occur in one or more. However, at pressures above 18 MPa, dedicated high-pressure equipment may be required, which would increase the cost of conducting the reaction.

[0049] The fixed bed reactor includes a mesoporous zeolite-supported metal catalyst. In an embodiment, the metal of the mesoporous zeolite-supported metal catalyst includes molybdenum, tungsten, or a combination thereof. According to one or more embodiments, the metal of the mesoporous zeolite-supported metal catalyst includes molybdenum, tungsten, or a combination thereof, and also includes nickel, cobalt, or a combination thereof. In some embodiments, the mesoporous zeolite-supported metal catalyst includes 2 wt % to 20 wt %, 3 wt % to 20 wt %, 3 wt % to 18 wt %, 3 wt % to 15 wt %, 5 wt % to 15 wt %, 7 wt % to 13 wt %, 8 wt % to 12 wt %, or 9 wt % to 11 wt % of molybdenum. According to one or more embodiments, the mesoporous zeolite-supported metal catalyst includes 0.1 wt % to 10 wt %, 0.1 wt % to 5 wt %, 0.2 wt % to 5 wt %, 0.5 wt % to 5 wt %, 0.5 wt % to 3 wt %, 1 wt % to 3 wt % or 1.5 wt % to 2.5 wt % of nickel, cobalt, or a combination thereof. In some embodiments, the mesoporous zeolite supported metal catalyst comprises 2 wt % to 20 wt % of platinum and 0.1 wt % to 5 wt % of nickel, cobalt or a combination thereof. According to one or more embodiments, the mesoporous zeolite supported metal catalyst comprises 0.1 wt % to 10 wt %, 0.1 wt % to 5 wt %, 0.2 wt % to 5 wt %, 0.5 wt % to 5 wt %, 0.5 wt % to 3 wt %, 1 wt % to 3 wt % or 1.5 wt % to 2.5 wt % of nickel. In some embodiments, the mesoporous zeolite supported metal catalyst comprises 5 wt % to 15 wt % of platinum and 0.5 wt % to 3 wt % of nickel.

[0050] The metal catalyst of mesoporous zeolite support includes zeolite carrier. Generally, zeolite can be characterized by the framework type defining its microporous structure. In one or more embodiments, the zeolite described at present is not particularly limited to framework type. For example, Ch.Baerlocher et al. described framework type in "Atlas of Zeolite Framework Types" of the fifth revised edition in 2001, which is incorporated herein by reference. In an embodiment, the zeolite may include a microstructure (including micropores), characterized in that, among others, * BEA framework zeolite (such as but not limited to beta zeolite), FAU framework zeolite (such as but not limited to Y-type zeolite), MOR framework zeolite or MFI framework zeolite (such as but not limited to ZSM-5). It should be understood that * BEA, MFI, MOR and FAU refer to the zeolite framework type identified by their respective three letter codes established by the International Zeolite Association (IZA). Other framework types are also considered in the embodiments of the present disclosure. In an embodiment, the zeolite support of the medium-pore zeolite-supported metal catalyst comprises a zeolite selected from the group consisting of beta zeolite, ZSM-5, mordenite, Y-type zeolite, and combinations thereof. In some embodiments, the zeolite support comprises a zeolite selected from the group consisting of beta zeolite, Y-type zeolite, and combinations thereof. According to one or more embodiments, the zeolite support comprises beta zeolite.

[0051] In some embodiments, the zeolite support of the medium pore zeolite supported metal catalyst has a silica to alumina molar ratio (SiO2 / Al2O3) of 10 to 50. According to one or more embodiments, the zeolite support has a silica to alumina molar ratio of 5 to 50, 10 to 50, 15 to 50, 20 to 50, 20 to 45, 25 to 45, 30 to 45, 30 to 40, or 35 to 40.

[0052] After the intermediate product in the liquid phase contacts the metal catalyst supported by the medium-pore zeolite in the fixed bed reactor zone, a gas phase and a liquid phase are generated. The gas phase and the liquid phase can be separated from each other using a liquid / gas separator. The gas phase can be discharged or collected. Conveniently, the gas phase can be analyzed before collection or discharge, so that the material balance before and after the reaction can be calculated. The liquid phase including BTEX can be cooled using, for example, a heat exchanger and then collected.

[0053] In an embodiment, 25% to 45% by weight of the mixed pyrolysis oil can be converted into BTEX ("total yield"). For example, the total yield can be 10% to 50%, 15% to 50%, 20% to 50%, 20% to 45%, 25% to 45%, 30% to 45%, 35% to 45%, or 38% to 42%. It is contemplated that the total yield can be from any lower limit disclosed herein to any upper limit disclosed herein.

[0054] In some embodiments, the multistage process consumes 80% to 100% of the DCPD in the mixed pyrolysis oil. According to one or more embodiments, the multistage process consumes 40% to 100%, 50% to 100%, 60% to 100%, 65% to 100%, 70% to 100%, 80% to 100%, 85% to 100%, 90% to 100%, 95% to 100% or 98% to 100% of the DCPD in the mixed pyrolysis oil.

[0055] The embodiments described herein can help limit the content of aromatic compounds in fuels, thereby helping to protect the environment. In addition, the embodiments ensure that aromatic compounds are produced under relatively mild conditions, which are valuable as intermediates in industry. For example, pyrolysis oil can now be used as a raw material for the production of para-xylene, which is a well-known intermediate for the production of PTA.

[0056] Aspects of the present disclosure include a first aspect, which includes a multistage method for upgrading a mixed cracking oil containing polyaromatic compounds to benzene, toluene, ethylbenzene and xylenes (BTEX), the method comprising: combining a light cracking oil with a heavy cracking oil to form a mixed cracking oil; upgrading the mixed cracking oil in a slurry reactor zone to produce an intermediate product, wherein the slurry reactor zone contains a mixed metal oxide catalyst; and hydrocracking the intermediate product in a fixed bed reactor zone to produce BTEX, wherein the fixed bed reactor zone contains a metal catalyst supported on a medium pore zeolite.

[0057] The second aspect includes the first aspect, wherein the mixed metal oxide catalyst comprises two or more of Fe2O3, ZrO2, CeO2, Al2O3, TiO2, MoO3, Co2O3 and NiO.

[0058] The third aspect includes the first aspect and the second aspect, wherein the mixed metal oxide catalyst comprises: 70 wt % to 90 wt % Fe2O3, 5 wt % to 60 wt % ZrO2, 1 wt % to 4 wt % CeO2; and 5 wt % to 10 wt % Al2O3, wherein the wt % is calculated based on the total amount of oxides.

[0059] A fourth aspect includes any one of the first to third aspects, wherein the metal of the medium-pore zeolite-supported metal catalyst comprises molybdenum.

[0060] The fifth aspect includes any one of the first to fourth aspects, wherein the metal of the medium-pore zeolite-supported metal catalyst further comprises nickel, cobalt, or a combination thereof.

[0061] A sixth aspect includes any one of the first to fifth aspects, wherein the medium pore zeolite-supported metal catalyst comprises 2 wt % to 20 wt % of molybdenum.

[0062] The seventh aspect includes any one of the first to sixth aspects, wherein the medium pore zeolite-supported metal catalyst further comprises 0.1 wt % to 5 wt % of nickel, cobalt, or a combination thereof.

[0063] An eighth aspect includes any one of the first to seventh aspects, wherein the medium pore zeolite-supported metal catalyst comprises: 5 wt % to 15 wt % of molybdenum; and 0.5 wt % to 3 wt % of nickel.

[0064] A ninth aspect includes any one of the first to eighth aspects, wherein the zeolite carrier comprises a zeolite selected from the group consisting of beta zeolite, ZSM-5, mordenite, Y-type zeolite, and combinations thereof.

[0065] A tenth aspect includes any one of the first to ninth aspects, wherein the zeolite carrier comprises a zeolite selected from the group consisting of beta zeolite, Y-type zeolite, and combinations thereof.

[0066] An eleventh aspect includes any one of the first to tenth aspects, wherein the zeolite support has a silica to alumina ratio of 10 to 50.

[0067] A twelfth aspect includes any one of the first to eleventh aspects, wherein the zeolite support has a silica to alumina ratio of 20 to 45.

[0068] A thirteenth aspect includes any one of the first to twelfth aspects, wherein the zeolite carrier comprises beta zeolite.

[0069] A fourteenth aspect includes any one of the first to thirteenth aspects, wherein the zeolite support has a silica to alumina ratio of 20 to 45.

[0070] A fifteenth aspect includes any one of the first to fourteenth aspects, wherein the zeolite support has a silica to alumina ratio of 35 to 40.

[0071] A sixteenth aspect includes any one of the first to fifteenth aspects, wherein 25% to 45% of the mixed pyrolysis oil is converted into BTEX.

[0072] The seventeenth aspect includes any one of the first to sixteenth aspects, wherein the mixed pyrolysis oil comprises: 5 wt % to 40 wt % of light pyrolysis oil; and 60 wt % to 95 wt % of heavy pyrolysis oil.

[0073] The eighteenth aspect includes any one of the first to seventeenth aspects, wherein the mixed pyrolysis oil contains dicyclopentadiene.

[0074] A nineteenth aspect includes any one of aspects one to eighteen, wherein the multi-stage process consumes 80% to 100% of the dicyclopentadiene in the mixed pyrolysis oil.

[0075] A twentieth aspect of the present disclosure includes any one of the first to nineteenth aspects, wherein the multi-stage process consumes 95% to 100% of the dicyclopentadiene in the mixed pyrolysis oil.

[0076] Example

[0077] Using the above-described embodiments, an exemplary protocol for producing BTEX was performed.

[0078] Synthesis of mixed metal oxide catalysts

[0079] An exemplary mixed metal oxide catalyst is formulated to have the following composition: 83 wt% Fe2O3, 7.5 wt% ZrO2, 2.5 wt% CeO2, and 7 wt% Al2O3, the concentrations being calculated on an oxide basis. Fe(NO3)3·9H2O (40 g) was dissolved in 800 ml of distilled water to form solution A. Al(NO3)3·9H2O (4.906 g), ZrO(NO3)2 (1.549 g), and Ce(NO3)3·6H2O (0.601 g) were added to solution A to produce solution B, which was stirred for 30 minutes. Ammonium hydroxide solution (40 ml, 28%-30%, based on NH3) was mixed with 60 ml of distilled water to produce solution C. Solution B was titrated to pH 7 by gradually adding solution C. The appropriately titrated solutions were mixed for one hour to form a precipitate. The precipitate was isolated and dried in an oven overnight. The dried solid was then calcined in air at 500° C. for two hours. The calcined product was crushed to obtain the final mixed metal oxide catalyst in powder form.

[0080] Synthesis of Metal Catalysts Supported by Mesoporous Zeolites

[0081] Six different mesoporous zeolite-supported metal (MZM) catalysts were prepared according to the following general steps. Appropriate amounts of metal precursors and zeolites were added to 100 mL of water in a 250 mL round-bottom flask equipped with a magnetic stirring bar. The mixture was stirred at 500 rpm for 1 hour, at which time the mixture was uniform. Water was removed by a rotary evaporator at 50 ° C under vacuum. The solid was dried at 100 ° C overnight. The dried solid was calcined at 550 ° C for 5 hours to obtain the catalyst.

[0082] Each of the catalysts prepared is listed in detail in Table 1. The zeolites used in the study were purchased from Zeolyst International. In particular, beta zeolite (SiO2 / Al2O3 ratio of 38) corresponds to Zeolyst product CP814C. Beta zeolite (SiO2 / Al2O3 ratio of 25) corresponds to Zeolyst product CP814E. Y-type zeolite (SiO2 / Al2O3 ratio of 30) corresponds to Zeolyst product CBV720. Zeolite Y (SiO2 / Al2O3 ratio of 12) corresponds to Zeolyst product CBV712.

[0083] The metal precursors used to prepare the MZM catalyst were purchased from Aldrich. The Mo precursor was (NH4)6Mo7O 24 ·4H2O, the Ni precursor is Ni(NO3)2·6H2O, and the Co precursor is Co(NO3)2·6H2O.

[0084] Table 1 Composition of prepared MZM catalyst

[0085]

[0086] Each catalyst was pretreated before being used in the process. For pretreatment, the catalyst was added to a fixed bed reactor and then heated to 400°C at a heating rate of 5°C / min at a hydrogen flow rate of 25 ml / min and atmospheric pressure. Once the reactor temperature reached 400°C, the reactor was pressurized to 3 MPa with hydrogen and then the hydrogen flow rate was maintained at a rate of 25 ml / min.

[0087] Obtaining BTEX from mixed pyrolysis oil

[0088] Heavy pyrolysis oil (16 g) was mixed with light pyrolysis oil (4 g) to form a mixed pyrolysis oil feed. The composition of the heavy pyrolysis oil is shown in Table 2, and the composition of the light pyrolysis oil is shown in Table 3.

[0089] Table 2 Composition of heavy pyrolysis oil

[0090]

[0091] Table 3 Composition of light pyrolysis oil

[0092]

[0093] The mixed cracking oil feed and mixed metal oxide catalyst (5g) prepared as above are added to the slurry reactor. Before the slurry reactor is pressurized to 14MPa with hydrogen, the slurry reactor is purged three times with hydrogen. The mixture is then heated to 400°C and stirred continuously for 4 hours. The reaction mixture is cooled to room temperature, the gas mixture is released and collected in a gas bag. The slurry is transferred to a centrifuge tube and centrifuged at 10000rpm for 20 minutes, and two layers appear after centrifugation. The top layer is the liquid product of stage 1, and the bottom is the used mixed metal oxide catalyst solid. The used mixed metal oxide catalyst is washed with toluene to remove possible condensate, and vacuum dried at 20°C to 100°C.

[0094] The liquid product of stage 1 was analyzed by simulated distillation (SIMDIS) gas chromatography, vacuum ultraviolet absorption gas chromatography (GC-VUV) and high performance liquid chromatography (HPLC). Based on the analysis, the liquid product of stage 1 contained 14.46 wt% of diaromatic hydrocarbons, 73.13 wt% of monoaromatic hydrocarbons, 8.75 wt% of dicyclopentadiene (DCPD) and 3.66 wt% of BTEX.

[0095] The liquid product of stage 1 was fed to a fixed bed reactor containing 0.5 g of pretreated catalyst at a feed rate of 0.6 g / hour. The fixed bed reactor stage was repeated for each MZM catalyst. The fixed bed reactor stage was also performed with a silicon carbide (SiC) catalyst as a blank control for comparison. In each experiment, the reactor temperature was maintained at 400°C and 3 MPa. The hydrogen flow rate was maintained at a rate of 25 ml / min and the reaction was carried out for 24 hours. After each reaction, the product mixture was separated into a gaseous component and a liquid component and analyzed. The product mixture of each embodiment is summarized in Table 4.

[0096] Table 4 Composition of the product mixture of each example

[0097]

[0098] Based on the product mixture, the total yield of BTEX and the consumption of DCPD were calculated. Using silicon carbide as a catalyst does not substantially change the composition of the liquid product of stage 1 (see Comparative Example 1). Each MZM catalyst increases the amount of BTEX and reduces the amount of DCPD from the liquid product of stage 1. The total yield of BTEX and the consumption of DCPD of the mixed pyrolysis oil are shown in Table 5.

[0099] Table 5 BTEX total yield and DCPD consumption of each example

[0100]

[0101] The use of silicon carbide as a catalyst provided a negligible BTEX yield (3.93%) and consumed only 6.77% of the DCPD. All of the MZM catalysts consumed at least 30% of the DCPD and provided a BTEX yield of at least 8%. All of the featured catalysts of Examples 1 to 3 had only molybdenum as the metal and had a Y-type zeolite support, but none provided a BTEX yield higher than 10.5%. So far, the best results were obtained using MZM 4 (BTEX yield 40.44%, DCPD consumption 97.46%) and MZM 5 (BTEX yield 33.62%, DCPD consumption 95.46%). MZM 4 containing Mo and Ni performed slightly better than MZM 5 containing Mo and Co. Both MZM 4 and MZM 5 contain beta zeolite with a silica to alumina ratio of 38 (see Table 1). Notably, as demonstrated by comparing Example 4 to Example 6, changing the silica to alumina ratio from 38 to 25 results in a substantial decrease in catalyst performance.

[0102] It is worth noting that the description in the present disclosure that the components of the present disclosure are "operable" or "sufficient" in a specific manner to manifest a specific property or function in a specific manner is a structural description, rather than a description of the intended use. More specifically, the reference in the present disclosure to the manner in which the components are "operable" or "sufficient" refers to the existing physical conditions of the components and, therefore, should be regarded as an explicit description of the structural characteristics of the components.

[0103] The singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise.

[0104] Ranges are provided throughout this disclosure. It is contemplated that each discrete value contained in a range is also included. In addition, it is also contemplated that a range can be formed by each discrete value contained in an explicitly disclosed range.

[0105] As used in this disclosure and the appended claims, the words "comprising," "having," and "including" and all grammatical variations thereof are intended to have an open, non-limiting meaning that does not exclude other elements or steps.

[0106] As used in the present disclosure, terms such as "first" and "second" are arbitrarily assigned and are intended only to distinguish between two or more instances or components. It should be understood that the words "first" and "second" are not used for other purposes, are not part of the component name or description, and do not necessarily define the relative position, orientation, or order of the components. In addition, it should be understood that the use of the terms "first" and "second" alone does not require the presence of any "third" component, although this possibility is contemplated within the scope of the present disclosure.

[0107] Having described the subject matter of the present disclosure in detail and with reference to specific embodiments, it should be noted that the various details disclosed in the present disclosure should not be considered to imply that these details are related to the elements of the essential components of the various embodiments described in the present disclosure. In addition, it is apparent that adjustments and changes can be made without departing from the scope of the present disclosure (including but not limited to the embodiments defined in the appended claims).

Claims

1. A multistage process for upgrading a mixed pyrolysis oil containing polyaromatic compounds to benzene, toluene, ethylbenzene and xylenes (BTEX), the process comprising: combining the light pyrolysis oil with the heavy pyrolysis oil to form the mixed pyrolysis oil; The mixed pyrolysis oil is upgraded in a slurry reactor zone to produce an intermediate product, wherein: The slurry reactor zone contains a mixed metal oxide catalyst; and The intermediate product is hydrocracked in a fixed bed reactor zone to produce BTEX, wherein the fixed bed reactor zone comprises a medium pore zeolite supported metal catalyst.

2. The multi-stage method according to claim 1, wherein: The mixed metal oxide catalyst comprises two or more of Fe2O3, ZrO2, CeO2, Al2O3, TiO2, MoO3, Co2O3 and NiO.

3. The multi-stage method according to claim 1 or claim 2, wherein: The mixed metal oxide catalyst comprises: 70 to 90 wt % Fe2O3; 5 to 60 wt% ZrO2; 1 wt % to 4 wt % CeO2; and 5 to 10 wt% Al2O3, The weight % is calculated based on the total amount of oxides.

4. The multi-stage method according to any one of claims 1 to 3, wherein: The metal of the medium pore zeolite supported metal catalyst comprises molybdenum.

5. The multi-stage method according to any one of claims 1 to 4, wherein: The metal of the medium pore zeolite supported metal catalyst further comprises nickel, cobalt or a combination thereof.

6. The multi-stage method according to any one of claims 1 to 5, wherein: The medium pore zeolite supported metal catalyst comprises 2 wt % to 20 wt % of molybdenum.

7. The multi-stage method according to any one of claims 1 to 6, wherein: The medium pore zeolite supported metal catalyst further comprises 0.1 wt % to 5 wt % of nickel, cobalt or a combination thereof.

8. The multi-stage method according to any one of claims 1 to 7, wherein: The medium-pore zeolite-supported metal catalyst comprises: 5 to 15 wt % molybdenum; and 0.5 to 3 wt % nickel.

9. The multi-stage method according to any one of claims 1 to 8, wherein: The zeolite support comprises a zeolite selected from the group consisting of beta zeolite, ZSM-5, mordenite, Y-type zeolite and combinations thereof.

10. The multi-stage method according to any one of claims 1 to 9, wherein: The zeolite support has a silica to alumina ratio of 10 to 50.

11. The multi-stage method according to any one of claims 1 to 10, wherein: The zeolite support comprises beta zeolite.

12. The multi-stage method according to any one of claims 1 to 11, wherein: 25% to 45% of the mixed pyrolysis oil is converted into BTEX.

13. The multi-stage method according to any one of claims 1 to 12, wherein: The mixed pyrolysis oil comprises: 5 to 40 wt% light pyrolysis oil; and 60% to 95% by weight of heavy pyrolysis oil.

14. The multi-stage method according to any one of claims 1 to 13, wherein: The mixed pyrolysis oil contains dicyclopentadiene.

15. The multi-stage method according to any one of claims 1 to 14, wherein: The multi-stage process consumes 80% to 100% of the dicyclopentadiene in the mixed pyrolysis oil.

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