Modified ultrastable Y (USY) zeolite catalysts for the dealkylation of aromatics

Abstract

The present disclosure relates to a process for the hydrodealkylation of aromatic-rich hydrocarbon streams to produce benzene, toluene, and mixed xylenes (BTX) with high selectivity toward valuable xylenes, using a catalyst containing a framework-substituted zirconium and / or titanium and / or hafnium-modified ultrastable Y (USY)-type zeolite.

Description

[Technical Field]

[0001] The present disclosure relates to a process for the hydrodealkylation of aromatics-rich hydrocarbon streams to produce benzene, toluene, and mixed xylenes (BTX) with high selectivity toward valuable xylenes, using a catalyst containing a framework-substituted zirconium and / or titanium and / or hafnium-modified ultrastable Y (USY)-type zeolite. [Background technology]

[0002] Catalytic reforming is a widely used process for reforming hydrocarbon mixtures to produce reformate, an aromatics-rich gasoline blending fraction useful for the production of aromatics. The reformate from the catalytic reforming unit is sent to an aromatics complex to recover high-value products, such as xylenes and benzene, and to convert lower-value products, such as toluene, into higher-value products. For example, toluene is typically recovered as a separate fraction and subjected to disproportionation to produce benzene and xylenes, or hydrodealkylated to produce benzene.

[0003] Aromatics complexes produce very heavy (boiling in the range of 100-450°C) effluent streams or bottoms containing C9+ alkylated aromatics, with alkyl groups containing three or more carbon atoms. Heavy bottoms fractions are not suitable as gasoline blending components because they reduce gasoline quality and adversely affect engine performance in the long term. Furthermore, blending is becoming more difficult due to increasingly stringent regulations on aromatics content in gasoline. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] U.S. Patent No. 10,293,332 [Patent Document 2] U.S. Patent Application Publication No. 2019 / 0194095 Summary of the Invention [Problem to be solved by the invention]

[0005] Para-xylene is experiencing a growing market rate of demand. As a result, converting heavy aromatics to p-xylene provides a valuable product stream. Therefore, it is desirable to utilize heavy reformate fractions to obtain xylene-rich BTX via dealkylation of alkylated aromatics. [Means for solving the problem]

[0006] A process and system for the hydrodealkylation of heavy aromatics-rich reformate using a catalyst containing a post-modified framework-substituted ultrastable Y (USY) zeolite is disclosed.

[0007] The present disclosure relates to a system for hydrodealkylating a bottoms stream from an aromatics recovery complex to produce benzene, toluene, and xylenes (BTX) with selectivity toward valuable xylenes. The process utilizes a catalyst containing a post-modified framework-substituted ultrastable Y (USY) zeolite in which titanium (Ti) and / or zirconium (Zr) and / or hafnium (Hf) are inserted into the zeolite catalyst after dealumination. The use of the modified USY zeolite catalyst according to the present disclosure results in a higher ratio of xylenes to toluene and benzene compared to known processes. Therefore, the process of the present disclosure provides the technical advantage of preferentially forming valuable xylenes and reducing the formation of less valuable benzene and toluene.

[0008] Thus, in some embodiments, the present disclosure provides a method for hydrodealkylating a hydrocarbon feed comprising aromatic hydrocarbons having 9 or more carbon atoms (C9+ aromatics) by reacting the hydrocarbon feed with a hydrogen feed in the presence of a dealkylation catalyst, wherein the dealkylation catalyst is a framework-substituted ultrastable Y (USY)-type zeolite.

[0009] In another embodiment, the present disclosure provides a process for producing mixed xylenes from a hydrocarbon feed comprising aromatic hydrocarbons having C9+ aromatics by reacting the hydrocarbon feed with a hydrogen feed in the presence of a dealkylation catalyst that hydrodealkylates aromatic compounds in the hydrocarbon feed, wherein the dealkylation catalyst is a framework-substituted ultrastable Y (USY)-type zeolite.

[0010] In some embodiments, the framework-substituted USY zeolite has a portion of the aluminum atoms that make up the zeolite framework substituted with zirconium and / or titanium and / or hafnium atoms. In other embodiments, the framework-substituted USY zeolite can be supported on a support containing an inorganic oxide, such as alumina, silica-alumina, etc., as described herein.

[0011] Preferably, the hydrocarbon feed comprises an aromatics-rich heavy reformate feed (eg, a bottoms stream) comprising aromatics-rich hydrocarbon oils having a boiling range of from about 50°C to about 500°C.

[0012] The process of the present invention results in the formation of a BTX fraction with strong selectivity toward xylenes. In some embodiments, the ratio of mixed xylenes to benzene and toluene is at least about 2 to 1, preferably at least about 3 to 1. In other embodiments, the ratio of benzene to toluene to xylenes is about 1:4 to 10:15 to 25.

[0013] Further embodiments and the full scope of applicability of the present disclosure will become apparent from the "Description of the Invention" provided herein below. However, it should be understood that the "Description of the Invention" and the specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this "Description of the Invention."

[0014] A more complete understanding of the present invention and its many features and advantages will be achieved by reference to the following Detailed Description and the accompanying drawings, in which: It is important to note that the drawings illustrate only one embodiment of the present disclosure and therefore should not be considered limiting of its scope. [Brief explanation of the drawings]

[0015] [Figure 1] FIG. 1 is a diagram of an embodiment of a method. DETAILED DESCRIPTION OF THE INVENTION

[0016] Although the scope of the devices and methods will be described in several embodiments, it is understood that one skilled in the relevant art will recognize that many examples, variations, and alternatives to the devices and methods described herein are within the scope and spirit of the present embodiments.

[0017] The described embodiments are therefore set forth without any loss of generality and without imposing limitations thereon, and those skilled in the art will appreciate that the scope of the present invention includes all possible combinations and uses of the specific features described herein.

[0018] Described herein are processes and systems for the production of mixed xylenes by hydrodealkylating a heavy hydrocarbon feed containing C aromatics (e.g., a heavy bottoms reformate feed). The heavy bottoms reformate feed and a hydrogen feed (e.g., hydrogen gas) are introduced into a dealkylation reactor containing a dealkylation catalyst. The dealkylation catalyst is a catalyst containing a framework-substituted ultrastable Y (USY) zeolite in which a portion of the aluminum atoms comprising the zeolite framework have been replaced with zirconium and / or titanium and / or hafnium atoms. The dealkylation effluent from the dealkylation reactor may optionally be introduced into a splitter unit for separating the components of the dealkylation effluent.

[0019] Advantageously, the use of catalysts containing framework-substituted ultrastable Y (USY) zeolites results in higher overall xylene production rates compared to other catalysts, and the process dealkylates C9+ aromatics to produce benzene, toluene, and mixed xylenes (BTX), with preference for the more valuable xylenes.

[0020] definition As used throughout, references to "C" and numbers refer to the number of carbon atoms in a hydrocarbon. For example, C6 refers to a hydrocarbon having 6 carbon atoms, C7 refers to a hydrocarbon having 7 carbon atoms, etc.

[0021] As used throughout this specification, "C8 aromatics" refers to aromatic hydrocarbons having 8 carbon atoms. Examples of C8 aromatic hydrocarbons include mixed xylenes and ethylbenzene. As used throughout this specification, "mixed xylenes" refers to one or more of paraxylene (p-xylene), metaxylene (m-xylene), and orthoxylene (o-xylene).

[0022] As used throughout this specification, "C9 aromatics" refers to aromatic hydrocarbons having 9 carbon atoms. Examples of C9 aromatic hydrocarbons include methylethylbenzene, trimethylbenzene, and propylbenzene.

[0023] As used throughout this specification, "C10+ aromatics" refers to aromatic hydrocarbons having 10 carbon atoms and aromatic hydrocarbons having more than 10 carbon atoms, for example, aromatic hydrocarbons having 11 carbon atoms. C10+ aromatics can include double-ring aromatic compounds. Examples of double-ring aromatic compounds of C10+ aromatics include naphthalene, methylnaphthalene, naphthalene derivatives, and combinations thereof. Examples of methylnaphthalenes include 1-methylnaphthalene, 2-methylnaphthalene, and combinations thereof.

[0024] As used throughout this specification, "C9+ aromatics" refers to the group of C9 aromatics and C10+ aromatics.

[0025] As used herein, the term "BTX" refers to a composition containing benzene (C6), toluene (C7), and mixed xylenes (C8). As used herein, the term "xylene" refers to any one of ortho-xylene (o-xylene), meta-xylene (m-xylene), para-xylene (p-xylene), or any combination thereof. As used throughout, "mixed xylenes" refers to any one or more of o-xylene, m-xylene, and p-xylene.

[0026] As used throughout this specification, a "dealkylation reaction" refers to a reaction that results in the removal of one or more alkyl groups from one or more of the reactants.

[0027] As used throughout this specification, "light hydrocarbons" refers to one or more of the following alkanes, including methane, ethane, propane, butane, pentane, alkenes, and trace amounts of naphthenes, e.g., cyclopentane, cyclohexane.

[0028] As used throughout this specification, "light gas" refers to one or more of light hydrocarbons, hydrogen, and air.

[0029] As used throughout this specification, "single ring aromatic compound" refers to an aromatic compound having at least six carbon atoms arranged in a central aromatic ring and containing a ring having hydrogen and hydrocarbons as substituents.

[0030] Description of the embodiment Referring to Figure 1, an embodiment of a process for producing mixed xylenes is provided. A heavy reformate feed 100 is introduced into a dealkylation reactor 10 along with a hydrogen feed 105. The heavy reformate feed 100 may include toluene, mixed xylenes, C9 aromatics, and C10+ aromatics as described below.

[0031] The hydrogen feed 105 can be any stream containing hydrogen gas. The hydrogen feed 105 can be a pure hydrogen stream from a virgin hydrogen source. In at least one embodiment, the hydrogen feed 105 can be from a hydrogen source in a refinery and can contain light hydrocarbons.

[0032] Dealkylation reactor 10 may be any type of reactor capable of containing and supporting the dealkylation reactants. Dealkylation reactor 10 may be a fixed bed reactor or a fluidized bed reactor. The dealkylation temperature in dealkylation reactor 10 may be between 400 degrees Celsius (°C) and 500°C. The dealkylation pressure in dealkylation reactor 10 may be between 20 bar (2,000 kilopascals (kPa)) and 50 bar (5,000 kPa). The liquid hourly space velocity (LHSV) is about 0.5 per hour (hr -1 ) for about 5 hours -1 The hydrogen to hydrocarbon ratio may be between about 100 and about 500 SLt / Lt.

[0033] The dealkylation reactor 10 includes a dealkylation catalyst containing a framework-substituted USY zeolite, in which a portion of the aluminum atoms comprising the zeolite framework have been replaced with zirconium and / or titanium and / or hafnium atoms, as described further below. The dealkylation catalyst can be selected to selectively convert one or more C aromatics in a dealkylation reaction. The dealkylation reaction can convert the C aromatics to toluene, benzene, mixed xylenes, and light gases. The reaction in the dealkylation reactor 10 can remove methyl, ethyl, propyl, butyl, and pentyl groups and their isomers attached to the C aromatics.

[0034] In at least one embodiment, the dealkylation catalyst may be selected to convert greater than 97.5 wt% of the methylethylbenzene to toluene. In at least one embodiment, the overall conversion of C9+ aromatics may be greater than 98 wt% due to the conversion of C9 aromatics and the removal of methyl, ethyl, propyl, butyl, and pentyl groups attached to the C10+ aromatics.

[0035] The dealkylation reaction produces a dealkylation effluent 110, which may contain mixed xylenes, toluene, benzene, light gases, and C9+ aromatics. The dealkylation effluent may then optionally be introduced into a splitter unit 20, which is operated to separate and recover various fractions. Splitter unit 20 may be any type of separation unit capable of separating a stream into its component parts. In at least one embodiment, splitter unit 20 may be a single splitter column designed to separate a feed stream into multiple split streams. In at least one embodiment, splitter unit 20 may be a series of multiple splitter columns designed to separate a single component from a feed stream. In at least one embodiment, splitter unit 20 may be one or more distillation units. In at least one embodiment, splitter unit 20 comprises a distillation column operating at a pressure between 4 barg and 6 barg and a temperature between 20°C and 100°C to separate light gases from the first column feed to produce a light gas stream 120 and a liquid reaction effluent 122 comprising C6+ hydrocarbons.

[0036] In at least one embodiment, splitter unit 20 separates the components to produce a light gas stream 120 and a liquid reaction effluent 122 containing BTX (C6-8 aromatic hydrocarbons) and a C9+ aromatics stream. In at least one embodiment, effluent 122 can be introduced into an aromatics recovery complex (ARC) 30, where such effluent is further processed to recover a BTX stream 124.

[0037] It will be understood by those skilled in the art that splitter unit 20 can be designed to operate at temperatures and pressures that produce the desired streams. In at least one embodiment where splitter unit 20 is a distillation column, the distillation column can comprise multiple sections within a single vessel, where each section has operating conditions corresponding to each of the separate columns described in this paragraph.

[0038] It will be apparent to those skilled in the art that the equipment for the hydrodealkylation process of the present disclosure is not limited to the embodiments specifically described above, and any other equipment may be used as long as the above reaction is carried out. Various types of equipment can be used. According to some embodiments, the process of the present disclosure can be carried out in an ebullated bed, a slurry bed, or a moving bed reactor, or a CSTR or a batch reactor, etc.

[0039] Hydrocarbon Feed The hydrocarbon feed 100 used in the process of the present disclosure can be any hydrocarbon feed rich in aromatic hydrocarbons. In a preferred embodiment, the hydrocarbon feed is a heavy reformate feed (also referred to herein as the "aromatic bottoms fraction") produced from an aromatics recovery process. The heavy reformate feed is preferably rich in aromatic hydrocarbons and may include toluene, mixed xylenes, C9 aromatics, and C10+ aromatics.

[0040] In at least one embodiment, the heavy reformate feed 100 can contain between 0 wt% and 10 wt% C6 aromatics (benzene). In at least one embodiment, the heavy reformate feed 100 can contain between 0 wt% and 10 wt% C7 aromatics (toluene). In at least one embodiment, the heavy reformate feed 100 can contain between 0 wt% and 10 wt% mixed xylenes. In at least one embodiment, the heavy reformate feed 100 can contain between 0 wt% and 10 wt% C6-C8 aromatics. In at least one embodiment, the heavy reformate feed 100 can contain between 0 wt% and 10 wt% mixed xylenes and between 60 wt% and 100 wt% C9+ aromatics. In at least one embodiment, the heavy reformate feed 100 can contain between 0 wt% and 40 wt% C6-C8 aromatics and between 60 wt% and 100 wt% C9+ aromatics. In at least one embodiment, the heavy reformate feed 100 can contain between 0 wt% and 10 wt% mixed xylenes, between 0 wt% and 10 wt% toluene, and between 80 wt% and 100 wt% C9+ aromatics. In at least one embodiment, the heavy reformate feed 100 contains between 60 wt% and 100 wt% C9+ aromatics. In at least one embodiment, the heavy reformate feed 100 contains between 60 wt% and 100 wt% C10+ aromatics. In at least one embodiment, the heavy reformate feed 100 contains between 90 wt% and 100 wt% C10+ aromatics. In at least one embodiment, the heavy reformate feed 100 contains between 60 wt% and 100 wt% C aromatics. In at least one embodiment, the heavy reformate feed 100 contains between 90 wt% and 100 wt% C aromatics.

[0041] In at least one embodiment, the heavy reformate feed 100 may contain trace amounts of C8+ naphthenes and C10+ naphthylenes, including alkyl derivatives thereof. In further embodiments, the heavy reformate feed 100 contains trace amounts of non-aromatic hydrocarbons. In at least one embodiment, the heavy reformate feed contains between 0 wt% and 1 wt% C4-C12 n-paraffins. In at least one embodiment, the heavy reformate feed 100 contains between 0 wt% and 1 wt% C4-C12 i-paraffins. In at least one embodiment, the heavy reformate feed 100 contains between 0 wt% and 1 wt% C8+ naphthenes and C10+ naphthylenes.

[0042] In some embodiments, the heavy reformate feed comprises an aromatics-rich hydrocarbon oil having a boiling range from about 50° C. to about 500° C. In other embodiments, the hydrocarbon feed comprises an aromatics-rich hydrocarbon oil having a boiling range from about 100° C. to about 500° C. In other embodiments, the heavy reformate feed comprises an aromatics-rich hydrocarbon oil having a boiling range from about 150° C. to about 500° C. In other embodiments, the heavy reformate feed comprises an aromatics-rich hydrocarbon oil having a boiling range from about 150° C. to about 400° C.

[0043] Reformate feeds usually contain very low amounts of sulfur because they are typically subjected to desulfurization before reforming so that the resulting gasoline product contains acceptable levels of sulfur for compliance with current sulfur specifications. In some embodiments, the dealkylated hydrocarbon product preferably contains less than about 500 ppm, preferably less than about 10 ppm, and most preferably less than about 0.5 ppm sulfur. In other embodiments, the dealkylated hydrocarbon product contains less than about 100 ppm, preferably less than about 10 ppm, and most preferably less than about 0.5 ppm nitrogen.

[0044] Dealkylated Products As a result of the dealkylation reaction, the amount of alkylated aromatics is reduced relative to the amount of alkylated aromatics in the initial feed. According to at least one embodiment, the hydrocarbon feed is dealkylated by at least about 50%. According to at least one embodiment, the hydrocarbon feed is dealkylated by at least about 60%. According to at least one embodiment, the hydrocarbon feed is dealkylated by at least about 70%.

[0045] Advantageously, the disclosed process produces a dealkylation product comprising benzene, toluene, mixed xylenes (BTX), C aromatics, and C aromatics. Optionally, the dealkylation product may contain trace amounts of C naphthenes, C naphthylenes, C-C n-paraffins, and / or C-C i-paraffins.

[0046] Advantageously, the disclosed process is characterized by the production of a BTX fraction having a strong selectivity for xylenes relative to benzene and toluene. Thus, in at least one embodiment, the process produces a greater amount of mixed xylenes than benzene and toluene. In at least one embodiment, the ratio of mixed xylenes to benzene and toluene is at least about 2 to 1. In at least one embodiment, the ratio of mixed xylenes to benzene and toluene is preferably at least about 3 to 1.

[0047] In another embodiment, the ratio of benzene to toluene to xylene is about 1:4-10:15-25 (expressed as benzene:toluene:xylene and normalized to benzene), hi another embodiment, the ratio of benzene to toluene to xylene is about 1:4-7:18-25.

[0048] Catalysts with framework-substituted ultrastable Y (USY) zeolites. Dealkylation reactor 10 may contain a dealkylation catalyst. Advantageously, the dealkylation catalyst contains a framework-substituted zeolite in which a portion of the aluminum atoms that make up the zeolite framework are replaced with zirconium and / or titanium and / or hafnium atoms.

[0049] In some embodiments, the catalyst having a framework-substituted zeolite catalyst used in the method of the present disclosure is an ultrastable Y-type zeolite in which silicon atoms and aluminum atoms form the zeolite framework, and a portion of the aluminum atoms are replaced with zirconium atoms and / or titanium atoms and / or hafnium atoms. For example, a framework-substituted zeolite in a catalyst in which a portion of the aluminum atoms forming the zeolite framework are replaced with only zirconium atoms is referred to as a "zirconium-substituted zeolite" or "Zr-USY"; a framework-substituted zeolite in a catalyst in which a portion of the aluminum atoms forming the zeolite framework of the framework-substituted zeolite are replaced with only titanium atoms is referred to as a "titanium-substituted zeolite" or "Ti-USY"; a framework-substituted zeolite in a catalyst in which a portion of the aluminum atoms forming the zeolite framework are replaced with only zirconium atoms and titanium atoms is referred to as a "zirconium.titanium-substituted zeolite" or "Zr . The framework-substituted zeolite in the catalyst, in which some of the aluminum atoms forming the zeolite framework are replaced with zirconium atoms, titanium, and hafnium atoms, is referred to as "zirconium.titanium.hafnium-substituted zeolite" or "Zr . Ti . It is called "Hf-USY".

[0050] The zirconium and / or titanium and / or hafnium atoms substituted for the aluminum atoms forming the framework of ultrastable zeolite Y act as framework building blocks for ultrastable zeolite Y. The substitution can be confirmed, for example, by ultraviolet, visible, and near-infrared spectroscopy (UV-Vis-NIR) and Fourier transform infrared spectroscopy (FT-IR).

[0051] In some embodiments, in addition to the substituted atoms, zirconium and / or titanium and / or hafnium atoms may be further attached (supported) outside of or bonded to the framework of the USY-type catalyst, as described in U.S. Pat. No. 10,293,332, the entire contents of which are incorporated herein by reference as if fully set forth herein.

[0052] In some embodiments, the framework-substituted zeolite of the catalyst contains from about 0.1% to about 5%, preferably from about 0.2% to about 4%, and more preferably from about 0.3% to about 3%, by weight of zirconium and / or titanium and / or hafnium atoms, based on the oxide (i.e., "ZrO2," "TiO2," and "HfO2") weight, based on the framework-substituted zeolite. As contemplated herein, the zirconium and / or titanium and / or hafnium atom content ranges (on an oxide basis) include the content of all zirconium and / or titanium and / or hafnium atoms that have substituted for aluminum atoms forming the zeolite framework, as well as the content of zirconium and / or titanium and / or hafnium atoms that have not substituted for said aluminum atoms.

[0053] It will be appreciated by those skilled in the art that when the framework-substituted zeolite in the catalyst contains zirconium atoms as described above, as well as titanium and / or hafnium atoms, the mass ratio (in terms of oxide) of zirconium atoms to titanium and / or hafnium atoms is not particularly limited, and any ratio of zirconium to titanium or hafnium that is effective in carrying out the process of the present invention may be used.

[0054] The content of zirconium atoms and / or titanium atoms and / or hafnium atoms in the framework-substituted zeolite in the catalyst can be measured using, for example, an X-ray fluorescence analyzer, a high-frequency plasma emission spectrometer, an atomic absorption spectrometer, or the like.

[0055] In some embodiments, the particles of the zirconium and / or titanium and / or hafnium modified USY catalyst have a diameter of 50 nm or less.

[0056] Method for producing framework-substituted zeolites The framework-substituted zeolite in the catalyst of the present invention can be prepared according to the method described in U.S. Patent No. 10,293,332. For example, the framework-substituted zeolite in the catalyst can be prepared by calcining USY-type zeolite at 500 to 700°C, so that the USY-type zeolite has a crystal lattice constant of 2.430 to 2.450 nm and a lattice constant of 600 to 900 m. 2 / g and a molar ratio of SiO2 to Al2O3 of 20 to 100; forming a suspension containing calcined USY zeolite, the suspension having a liquid / solid mass ratio of 5 to 15; adding an inorganic or organic acid to the suspension so that the pH of the suspension is 1.0 to 2.0; subsequently adding a solution containing a zirconium compound and / or a hafnium compound and mixing them; and neutralizing the solution, for example with aqueous ammonia, so that the mixed solution has a pH of about 7.

[0057] Ultrastable Y-type zeolite is used as one of the raw materials for preparing framework-substituted zeolites in catalysts. Ultrastable Y-type zeolite has a crystal lattice constant (UD) falling within the range of 2.430 nm to 2.450 nm, and a lattice constant (UD) of 600 to 900 nm. 2 / g and a molar ratio of SiO2 to Al2O3 (silica-alumina ratio) falling within the range of 20 to 100. Ultrastable Y-type zeolites can be prepared by any method known in the art.

[0058] In a method for producing framework-substituted ultrastable Y zeolite, extraframework aluminum (aluminum atoms that do not form the zeolite framework) can be removed from the raw ultrastable Y zeolite to obtain the ultrastable Y zeolite. The extraframework aluminum can be removed, for example, by dispersing the ultrastable Y zeolite in warm water at 40 to 95°C to prepare a suspension, adding sulfuric acid to the suspension, and stirring the suspension for 10 minutes to 3 hours while maintaining the temperature at 40 to 95°C, thereby dissolving the extraframework aluminum. After dissolving the extraframework aluminum, the suspension is filtered, and the residue on the filter is washed with pure water at 40 to 95°C and dried at 100 to 180°C for 3 to 30 hours to obtain the ultrastable Y zeolite from which the extraframework aluminum has been removed.

[0059] Furthermore, in the method for producing a framework-substituted ultrastable Y-type zeolite, the raw material ultrastable Y-type zeolite can be calcined at 500°C to 700°C, preferably 550°C to 650°C. The calcination time is not particularly limited as long as the target framework-substituted zeolite is obtained, and it is, for example, calcined within a range of 30 minutes to 10 hours. The calcination atmosphere for the ultrastable Y-type zeolite is preferably air. The calcined ultrastable Y-type zeolite is suspended in water having a temperature of about 20°C to about 30°C to form a suspension. Regarding the concentration of the suspension of ultrastable Y-type zeolite, the liquid / solid mass ratio is preferably within a range of 5 to 15, more preferably 8 to 12.

[0060] Next, an inorganic acid or an organic acid is added to the suspension so that the pH of the suspension is adjusted to 1.0 to 2.0, and then a solution containing a zirconium compound and / or a hafnium compound is added and mixed. The mixed solution is then neutralized (pH 7.0 to 7.5) and dried at 80 to 180°C as desired, thereby obtaining the framework-exchanged zeolite described above.

[0061] Sulfuric acid, nitric acid, hydrochloric acid, etc. can be provided as the inorganic acid used above, and among them, sulfuric acid, hydrochloric acid, etc. are particularly preferred. Furthermore, carboxylic acids can be suitably used as the organic acids described above. The amount of inorganic acid or organic acid used is not limited as long as the pH of the suspension can be adjusted to a range of 1.0 to 2.0. The amount is, for example, 0.5 to 4.0 times, preferably 0.7 to 3.5 times, the molar amount based on the amount of Al2O3 in the ultrastable Y-type zeolite, but is not limited to the above range.

[0062] Examples of the zirconium compound described above include zirconium sulfate, zirconium nitrate, and zirconium chloride. Among these compounds, zirconium sulfate and zirconium nitrate are particularly preferred. The amount of the zirconium compound added is preferably about 0.1% by mass to about 5% by mass, more preferably about 0.2% by mass to about 4% by mass, based on the zirconium oxide for the ultrastable Y-type zeolite described above. Typically, an aqueous solution of a zirconium compound prepared by dissolving a zirconium compound in water is preferably used as the zirconium compound.

[0063] Examples of the hafnium compound described above include hafnium chloride, hafnium nitrate, hafnium fluoride, hafnium bromide, and hafnium oxalate. Among these compounds, hafnium chloride and hafnium nitrate are particularly preferred. The amount of hafnium compound added is preferably about 0.1% by mass to about 5% by mass, more preferably about 0.2% by mass to about 4% by mass, based on the hafnium oxide content of the ultrastable Y-type zeolite. Typically, an aqueous solution of a hafnium compound prepared by dissolving a hafnium compound in water is preferably used as the hafnium compound.

[0064] In some embodiments, a titanium compound can be added to the mixed solution described above. Examples of titanium compounds include titanium sulfate, titanium acetate, titanium chloride, titanium nitrate, and titanium lactate. Among these compounds, titanium sulfate, titanium acetate, and the like are particularly preferred. The amount of titanium compound added is preferably about 0.1% by mass to about 5% by mass, more preferably about 0.2% by mass to about 4% by mass, based on the oxide content of the ultrastable Y-type zeolite. Typically, an aqueous solution of a titanium compound prepared by dissolving the titanium compound in water is preferably used as the titanium compound.

[0065] The pH of the suspension must be adjusted beforehand to 1.0-2.0 in order to prevent precipitation from occurring when the aqueous solution of zirconium, hafnium or titanium compounds is mixed with the suspension of ultrastable Y zeolite described above.

[0066] When an aqueous solution of a zirconium compound, a hafnium compound, or a titanium compound is mixed with a suspension of ultrastable Y-type zeolite, the aqueous solution is preferably added gradually to the suspension. After the addition of the aqueous solution to the suspension is completed, the solution is mixed, for example, at room temperature (about 25°C to about 35°C) for 3 to 5 hours, preferably with stirring. Furthermore, after the mixing is completed, the mixed solution is neutralized by adding an alkali such as aqueous ammonia to adjust its pH to 7.0 to 7.5, thereby obtaining the framework-substituted zeolite in the catalyst.

[0067] When only a zirconium compound (or an aqueous solution thereof) is used as the compound (or an aqueous solution thereof) added to the suspension described above, a framework-substituted zeolite in the catalyst (Zr-USY) is formed in which zirconium atoms have substituted for some of the aluminum atoms forming the framework of the ultrastable Y-type zeolite; when only a hafnium compound (or an aqueous solution thereof) is used, a framework-substituted zeolite in the catalyst (Hf-USY) is formed in which hafnium atoms have substituted for some of the aluminum atoms forming the framework of the ultrastable Y-type zeolite; when only a titanium compound (or an aqueous solution thereof) is used, a framework-substituted zeolite in the catalyst (Ti-USY) is formed in which titanium atoms have substituted for some of the aluminum atoms forming the framework of the ultrastable Y-type zeolite; when a zirconium compound and a titanium compound (or an aqueous solution thereof) are used, a framework-substituted zeolite in the catalyst (Zr-USY) is formed in which zirconium atoms and titanium atoms have substituted for some of the aluminum atoms forming the framework of the ultrastable Y-type zeolite. . When zirconium and hafnium compounds (or their aqueous solutions) are used, the zirconium and hafnium atoms replace some of the aluminum atoms that form the framework of the ultrastable Y zeolite, forming a catalyst (Zr .When zirconium, titanium and hafnium compounds (or their aqueous solutions) are used, the zirconium, titanium and hafnium atoms are substituted for some of the aluminum atoms that form the framework of the ultrastable Y zeolite (Zr . Ti . It will be apparent to those skilled in the art that framework-substituted zeolites in Hf-USY are formed.

[0068] The resulting framework-substituted zeolite in the catalyst is preferably filtered, washed with water, and dried at about 80°C to about 180°C, if desired.

[0069] In addition to the framework-substituted zeolite in the catalyst described above, the framework-substituted USY zeolite can be supported on a support containing an inorganic oxide other than the framework-substituted zeolite in the catalyst described above. The inorganic oxide typically contains a material that acts as a grinding agent or binder. Known materials typically contained in supports containing ultrastable Y-type zeolites and known materials used as grinding agents can be used. Examples of inorganic oxides include, but are not limited to, alumina, silica, titania, silica-alumina, alumina-titania, alumina-zirconia, alumina-boria, phosphorus-alumina, silica-alumina-boria, phosphorus-alumina-boria, phosphorus-alumina-silica, silica-alumina-titania, and silica-alumina-zirconia. In the present disclosure, inorganic oxides primarily consisting of alumina and silica-alumina are particularly preferred.

[0070] The content of the framework-substituted zeolite in the catalyst and the content of the inorganic oxide in the support can be appropriately determined depending on the purpose. The support contains about 2% by mass to about 80% by mass, preferably about 10% by mass to about 80% by mass, and more preferably about 20% by mass to about 70% by mass of the framework-substituted zeolite in the catalyst, and has an inorganic oxide content of about 98% by mass to about 20% by mass, preferably about 90% by mass to about 20% by mass, and more preferably about 80% by mass to about 30% by mass.

[0071] Metal composition: The catalyst used in the method of the present disclosure may further comprise an active metal component selected from the group consisting of metals in IUPAC Groups 6 to 11 of the periodic table. Examples of active metals include iron, cobalt, nickel, rhodium, palladium, silver, iridium, platinum, or gold, which are in Group 8 of the long-form periodic table, and / or chromium, molybdenum, or tungsten, which are in Group 6. Preferred examples of metal components include a combination of molybdenum or tungsten, which are in Group 6, and a combination of cobalt or nickel, which are in Group 8, and a platinum group metal component (platinum, rhodium, palladium, etc.).

[0072] When present, the metal component may be contained in the catalyst in an amount of about 0.0001 to about 40 mass% as oxide. In the case of molybdenum, tungsten, cobalt, or nickel, the amount thereof is particularly preferably about 3 to about 30 mass% as oxide, based on the mass of the catalyst. In the case of platinum group metals (platinum, rhodium, palladium, etc.), when present, the amount thereof is particularly preferably about 0.01 to about 2 mass% as metal. [Example]

[0073] The following examples are provided to better illustrate embodiments of the present disclosure, however, it should be understood that these examples are merely exemplary in nature and that embodiments of the presently disclosed methods are not necessarily limited thereto.

[0074] Example 1 Example 1 shows the analysis of the dealkylation reactor 10 (see Figure 1). The heavy reformate feed 100 has the composition in Table 1. The composition and properties of the feedstock are summarized in Table 1. The detailed composition obtained from PIONA analysis is shown in Table 2.

[0075] [Table 1]

[0076] [Table 2]

[0077] The pilot plant test conditions are summarized in Table 3.

[0078] [Table 3]

[0079] The catalyst was a framework-substituted ultrastable Y (USY) zeolite in which some of the aluminum atoms constituting the zeolite framework were replaced with zirconium and titanium atoms, and it further contained nickel (Ni) and molybdenum (Mo) as active metals.

[0080] result: The results of aromatic dealkylation are shown in Table 4 (reaction temperature: 400°C) and Table 5 (reaction temperature: 425°C).

[0081] [Table 4]

[0082] [Table 5]

[0083] The benzene / toluene / xylene ratios obtained according to the experiments in Table 4 are summarized in Table 6.

[0084] [Table 6]

[0085] The benzene / toluene / xylene ratios obtained according to the experiments in Table 5 are summarized in Table 7.

[0086] [Table 7]

[0087] Comparative Example: Table 8 shows the benzene / toluene / xylene ratios obtained according to the method of U.S. Patent Application Publication No. 2019 / 0194095, Example 1. The method of U.S. Patent Application Publication No. 2019 / 0194095 uses a ZSM-5 zeolite catalyst at 400° C. U.S. Patent Application Publication No. 2019 / 0194095 is expressly incorporated herein by reference in its entirety.

[0088] [Table 8]

[0089] As can be seen, the process of the present disclosure produces a product with a benzene:toluene:xylene ratio of 1.0:6.7:19.5 at 400°C and 1.0:5.0:21.8 at 425°C, while the process of U.S. Patent Application Publication No. 2019 / 0194095 results in a benzene:toluene:xylene ratio of 1.0:6.5:6.6 at 400°C.

[0090] Thus, the process of U.S. Patent Application Publication No. 2019 / 0194095 using a ZSM-5 catalyst has similar ratios / selectivities toward toluene and xylenes. However, the process of the present disclosure using framework-substituted ultrastable Y (USY) zeolites has a stronger selectivity toward xylenes over benzene and toluene. Therefore, the use of the modified USY zeolite catalyst of the present disclosure provides the technical advantage of producing a higher proportion of desirable, valuable xylenes over toluene and benzene.

[0091] The foregoing description of specific embodiments makes quite fully apparent the general nature of this invention, which others may readily modify and / or adapt to various applications of such specific embodiments by applying knowledge within their skill in the art (including the content of references cited herein) without undue experimentation and without departing from the general concepts of the present disclosure. Such adaptations and modifications are therefore intended to be within the meaning and range of equivalents of the disclosed embodiments, based on the teaching and guidance provided herein. It is understood that the terminology or terminology used herein is for purposes of description and not limitation, and will be interpreted by one of ordinary skill in the art in light of the teaching and guidance provided herein, in combination with the knowledge of such artisan. [Explanation of symbols]

[0092] 10 Dealkylation reactor 20 Splitter Unit 30 Aromatics Recovery Complex (ARC) 100 Heavy Reformate Feed 105 Hydrogen Feed 110 Dealkylation Effluent 120 Light Gas Stream 122 Liquid reaction effluent 124 BTX style

Claims

1. 1. A process for hydrodealkylating a hydrocarbon feed to produce a dealkylated product, comprising: The method comprises reacting a hydrocarbon feed with a hydrogen feed in the presence of a dealkylation catalyst; the hydrocarbon feed comprises aromatic hydrocarbons having 9 or more carbon atoms (C9+ aromatics); The method of claim 1, wherein the dealkylation catalyst is a framework-substituted ultrastable Y (USY) zeolite in which a portion of the aluminum atoms constituting the zeolite framework are substituted with zirconium atoms and / or titanium atoms and / or hafnium atoms.

2. A method of producing a hydrocarbon feed comprising the steps of: introducing said hydrocarbon feed and said hydrogen feed into a dealkylation reactor, said dealkylation reactor comprising said dealkylation catalyst; reacting said hydrocarbon feed with said hydrogen feed in the presence of said dealkylation catalyst to produce a dealkylated product; The method of claim 1 further comprising:

3. 3. The method of claim 1, wherein the framework-substituted USY zeolite in the dealkylation catalyst comprises zirconium and titanium atoms.

4. 3. The method according to claim 1, wherein the framework-substituted USY zeolite in the dealkylation catalyst contains 0.1 to 5 mass % of zirconium atoms and / or titanium atoms and / or hafnium atoms, each calculated on an oxide basis.

5. 3. The method of claim 1 or 2, wherein the framework-substituted USY zeolite in the dealkylation catalyst further comprises a support comprising an inorganic oxide selected from the group consisting of alumina, silica-alumina, and combinations thereof.

6. 3. The method of claim 1, wherein the framework-substituted USY zeolite in the dealkylation catalyst further comprises alumina as a binder.

7. 3. The method of claim 1, wherein the dealkylation catalyst further comprises an active metal selected from the group consisting of metals from IUPAC Groups 6 to 11 of the Periodic Table.

8. 3. The method of claim 1 or 2, wherein the dealkylation products comprise benzene, toluene, mixed xylenes (BTX), and C9+ aromatics.

9. 9. The method of claim 8, wherein the mixed xylenes are produced in an amount greater than benzene and toluene.

10. 10. The method of claim 9, wherein the ratio of mixed xylenes to benzene and toluene, expressed as mixed xylenes:benzene+toluene, is at least 2:

1.

11. The method of claim 10, wherein the ratio of mixed xylenes to benzene and toluene, expressed as mixed xylenes:benzene+toluene, is at least 3:

1.

12. 10. The process of claim 9, wherein the ratio of benzene to toluene to xylene in the dealkylated product is 1:4 to 10:15 to 25.

13. 3. The method of claim 1 or 2, wherein the hydrocarbon feed comprises an aromatics-rich hydrocarbon oil having a boiling point range of 50°C to 500°C.

14. 3. The method of claim 1 or 2, wherein the hydrocarbon feed comprises a heavy reformate feed rich in aromatics.

15. A reaction temperature range of 400°C to 500°C, a pressure of 20 to 50 bar, and a reaction time of 0.5 to 5 hours. -1 and a hydrogen to hydrocarbon ratio of 100 to 500 SLt / Lt.

16. The process of claim 1 or 2, operated at a reaction temperature range of 400°C to 425°C.

17. 3. The method of claim 1 or 2, wherein the hydrogen feed comprises hydrogen gas.

18. 3. The method of claim 1 or 2, wherein the dealkylated product contains less than 500 ppm sulfur.

19. The method of claim 1 or 2, wherein the dealkylated product contains less than 10 ppm sulfur.

20. The method of claim 1 or 2, wherein the dealkylated product contains less than 0.5 ppm sulfur.

21. 3. The method of claim 1 or 2, wherein the dealkylated product contains less than 100 ppm nitrogen.

22. The method of claim 1 or 2, wherein the dealkylated product contains less than 10 ppm nitrogen.

23. The method of claim 1 or 2, wherein the dealkylated product contains less than 0.5 ppm nitrogen.

24. 3. The process of claim 1 or 2, wherein the hydrocarbon feed is at least 50 wt% dealkylated.

25. The method of claim 1 or 2, wherein the hydrocarbon feed is at least 60 wt% dealkylated.

26. The method of claim 1 or 2, wherein the hydrocarbon feed is at least 70 wt% dealkylated.

27. 3. The method of claim 1 or 2, further comprising the steps of introducing the dealkylated product into a splitter unit and separating the dealkylated product into a light hydrocarbon stream and a stream comprising C6+ aromatic hydrocarbons.

28. 28. The method of claim 27, wherein the C6+ aromatic hydrocarbon stream comprises benzene, toluene, mixed xylenes (BTX), and C9+ aromatic hydrocarbons.

29. 30. The method of claim 28, further comprising introducing the C6+ aromatic hydrocarbon stream into an aromatics recovery complex (ARC) to recover BTX.

30. 1. A process for producing mixed xylenes from a hydrocarbon feed, comprising: reacting a hydrocarbon feed with a hydrogen feed in the presence of a dealkylation catalyst to hydrodealkylate aromatic hydrocarbons in the hydrocarbon feed; the hydrocarbon feed comprises aromatic hydrocarbons having 9 or more carbon atoms (C9+ aromatics); The method of claim 1, wherein the dealkylation catalyst is a framework-substituted ultrastable Y (USY) zeolite in which a portion of the aluminum atoms constituting the zeolite framework are substituted with zirconium atoms and / or titanium atoms and / or hafnium atoms.

31. 31. The method of claim 30, wherein the hydrocarbon feed is a heavy reformate feed.

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