Mesoporous FAU zeolites, their production and use in heavy oil upgrading
阅读说明：本技术 中孔fau沸石、其生产和其在重油升级中的用途 (Mesoporous FAU zeolites, their production and use in heavy oil upgrading ) 是由 丁连辉 埃萨姆·阿尔-萨伊德 卡里穆丁·沙克 阿布德努尔·布兰 于 2018-05-01 设计创作，主要内容包括：根据本文所公开的一个或多个实施例,中孔沸石可以通过包括以下的方法制备：使初始沸石材料与六氟硅酸铵接触,以使所述初始沸石材料的框架改性,以及在所述框架改性的沸石材料中形成中孔。所述接触可以形成框架改性的沸石材料。所述中孔沸石可以掺入到催化剂中。(According to one or more embodiments disclosed herein, the mesoporous zeolite may be prepared by a method comprising: contacting an initial zeolitic material with ammonium hexafluorosilicate to modify the framework of the initial zeolitic material and form mesopores in the framework-modified zeolitic material. The contacting may form a framework-modified zeolite material. The mesoporous zeolite may be incorporated into a catalyst.)
1. A process for preparing a mesoporous zeolite, the process comprising:
contacting an initial zeolitic material with ammonium hexafluorosilicate to modify the framework of the initial zeolitic material, forming a framework-modified zeolitic material, the initial zeolitic material comprising silica and alumina and comprising FAU framework-type structures; and
mesopores are formed in the framework-modified zeolite material.
2. The method of claim 1, wherein the initial zeolitic material comprises ammonium and sodium.
3. The method of claim 2, wherein the initial zeolitic material is formed by ion-exchanging a zeolite comprising sodium with ammonium.
4. The method of any one of claims 1-3, wherein forming the mesopores comprises:
combining the framework-modified zeolitic material with one or more of a base or a surfactant, cetrimide, to form a mixture; and
heating the mixture to an elevated temperature for a heating period of time to form the mesopores.
5. The method of claim 4, wherein:
the elevated temperature is from 100 ℃ to 150 ℃ and the heating period is from 1 day to 5 days; or
The base comprises an aqueous solution comprising one or more of NaO, KOH, or ammonium hydroxide; or
And both.
6. The method of any one of claims 1-5, wherein the surfactant is cetrimide.
7. The process of any one of claims 1 to 6, wherein the ammonium hexafluorosilicate contacted with the initial zeolite is in an aqueous solution.
8. The method of any one of claims 1-7, further comprising separating the zeolite comprising mesopores from other contents of the mixture.
9. The process of any one of claims 1 to 8 wherein the medium pore zeolite has a crystallinity of at least 90% relative to the initial zeolite.
10. A method of preparing a catalyst, the method comprising:
forming a mesoporous zeolite by a process comprising:
contacting an initial zeolitic material with ammonium hexafluorosilicate to modify the framework of the initial zeolitic material, forming a framework-modified zeolitic material, the initial zeolitic material comprising silica and alumina and comprising FAU framework-type structures; and
forming mesopores in the framework-modified zeolite material to form a mesoporous zeolite; and
admixing the mesoporous zeolite with a metal oxide support material and one or more metal catalyst materials to form the catalyst.
11. The method of claim 10, wherein one or more of the metal catalyst materials comprises a W, Mo, Ni, or Co oxide or sulfide.
12. The method of claim 10 or 11, wherein the catalyst comprises a W oxide or sulfide and a Ni oxide or sulfide.
13. The method of claim 12, wherein the catalyst comprises:
20 to 26 wt.% of a W oxide or sulfide;
4 to 6 wt.% of a Ni oxide or sulfide;
10 to 60 wt.% of the medium pore zeolite; and
10 to 70 wt.% of alumina.
14. The method of any one of claims 10 or 11, wherein the catalyst comprises Mo and Ni oxides or sulfides.
15. The method of claim 14, wherein the catalyst comprises:
14 to 16 wt.% Mo oxide or sulfide;
4 to 6 wt.% of a Ni oxide or sulfide;
10 to 60 wt.% of the medium pore zeolite; and
20 to 80 wt.% alumina.
Technical Field
The present disclosure relates to zeolites, and more particularly, to zeolites that may be suitable for treating heavy oils including crude oil using a catalytic pretreatment process.
Background
Ethylene, propylene, butylene, butadiene and aromatics such as benzene, toluene and xylene are essential intermediates for most petrochemical industries. They are obtained mainly by thermal cracking (sometimes referred to as "steam pyrolysis" or "steam cracking") of petroleum gases and distillates such as naphtha, kerosene or even gas oil. These intermediate compounds may also be produced by a refinery Fluid Catalytic Cracking (FCC) process, wherein heavy feedstocks such as gas oils or resids are converted. For example, an important source of propylene production is refined propylene from an FCC unit. However, distillate feedstocks such as gas oils or residues are often limited and result from several expensive and energy intensive processing steps within the refinery.
However, as the demand for these basic intermediate compounds increases, other production sources must be considered in addition to traditional thermal cracking processes that use petroleum gas and distillate as feedstocks.
Disclosure of Invention
Accordingly, in view of the ever-increasing demand for such intermediate petrochemical products as butenes, there is a need for processes for producing these intermediate compounds from other types of feedstocks that are available in large quantities and/or at relatively low cost. The present disclosure relates to the production of mesoporous zeolites, such as mesoporous zeolite Y, which may be used in methods and systems for producing these intermediate compounds, sometimes referred to herein as "system products," by direct conversion of heavy oil feedstocks, such as crude oil, according to one or more embodiments. Conversion from crude oil feedstocks can be beneficial compared to other available feedstocks for producing these intermediate compounds, as crude oil can generally be less expensive and/or more widely available than other feedstock materials.
In accordance with one or more embodiments, heavy oil can be cracked by steam cracking to form system products, such as light olefins, e.g., butenes. However, steam cracking of heavy oil can lead to increased coking, which can require that refinery operations be stopped to remove coke. In addition, relatively large amounts of aromatic compounds in the heavy oil can lead to steam cracking of the heavy oil to form undesirable products and relatively low light olefin content. In some cases, the polyaromatics present in the heavy oil feedstock may not be convertible by steam cracking. It has been found that pre-treating a heavy oil feedstock to reduce or remove aromatics and other undesirable materials such as one or more of metals, sulfur, and nitrogen can increase the production of light olefins and reduce coking. According to one or more embodiments, such pretreatment may include one or more of hydrodemetallization, hydrodenitrogenation, hydrodesulfurization, or hydrocracking of aromatic compounds.
Due at least in part to its relatively weak acidity, conventional hydrotreating catalysts may not be effective in converting polyaromatics and saturated polyaromatics. Hydrocracking catalysts such as those used in hydrocracking having zeolite as a key cracking component may be much more acidic than conventional hydrotreating catalysts and may greatly increase the conversion of aromatics. However, the open pores of conventional zeolites may be too small to allow relatively large molecules in the heavy oil feedstock to diffuse into the active sites located inside the zeolite.
An effective way to address this problem (i.e., the problem of increasing the conversion of relatively large molecular aromatic compounds present in the heavy oil stream) has been to include mesopores in the zeolite, thereby increasing the zeolite pore size. For example, in one or more embodiments, increased pore size can be achieved by incorporating mesopores in previously formed zeolite crystals.
According to embodiments disclosed herein, zeolite Y comprising mesopores can be produced and used as a hydrocracking catalyst. As described herein, in some embodiments, with the presently described zeolite Y as the bottom bed hydrocracking catalyst, the 540℃ + fraction in the hydrotreated arabian light crude may be partially or even completely converted to a light fraction having a high percentage paraffin content. Additionally, in some embodiments, the presently described zeolite Y can be produced in reduced synthesis time and reduced number of synthesis steps compared to other zeolite catalysts.
According to one or more embodiments, the mesoporous zeolite may be prepared by a method comprising: contacting an initial zeolitic material with ammonium hexafluorosilicate to modify the framework of the initial zeolitic material and form mesopores in the framework-modified zeolitic material. The contacting may form a framework-modified zeolite material. The initial zeolite material may include silica and alumina, and may include a FAU framework type structure.
According to one or more further embodiments, the catalyst may be prepared by a method comprising: forming a mesoporous zeolite, and admixing the mesoporous zeolite with a metal oxide support material and one or more metal catalyst materials to form the catalyst. The mesoporous zeolite may be formed by a process comprising: contacting an initial zeolitic material with ammonium hexafluorosilicate to modify the framework of the initial zeolitic material, and forming mesopores in the framework-modified zeolitic material to form a mesoporous zeolite. The contacting may form a framework-modified zeolite material. The initial zeolite material may include silica and alumina, and may include a FAU framework type structure.
Additional features and advantages of the technology disclosed in this disclosure will be set forth in the detailed description which follows, and in part will be readily apparent to those skilled in the art from that description or recognized by practicing the technology as described in the present disclosure, including the detailed description which follows, the claims, as well as the appended drawings.
Drawings
The following detailed description of specific embodiments of the present disclosure can be best understood when read in conjunction with the following drawings, where like structure is indicated with like reference numerals and in which:
fig. 1 is a generalized diagram of a chemical pretreatment system including a pretreatment reactor including a Hydrodemetallization (HDM) catalyst, a transition catalyst, a Hydrodesulfurization (HDS) catalyst/Hydrodenitrogenation (HDN) catalyst, and a hydrocracking catalyst according to one or more embodiments described in the present disclosure;
FIG. 2 is a generalized diagram of a chemical treatment system used after the chemical pretreatment system of FIG. 1, including a steam cracking unit, according to one or more embodiments described in the present disclosure; and is
For purposes of the simplified schematic illustration and description of fig. 1 and 2, the numerous valves, temperature sensors, electronic controllers, etc., that may be employed in certain chemical processing operations and are well known to those of ordinary skill in the art, are not included. Further, accompanying components, such as, for example, air supplies, catalyst hoppers, and flue gas treatment, which are often included in conventional chemical treatment operations, such as refineries, are not depicted. Such components are known to be within the spirit and scope of the embodiments of the disclosed invention. However, operational components, such as those described in this disclosure, may be added to the embodiments described in this disclosure.
It should be further noted that the arrows in the drawings refer to process flows. However, an arrow may equivalently refer to a transfer line that may be used to transfer a process stream between two or more system components. In addition, the arrows connected to the system components define an inlet or outlet in each given system component. The direction of the arrow generally corresponds to the main direction of movement of the material of the stream contained within the physical transport line represented by the arrow. Further, an arrow not connecting two or more system components represents a product stream exiting the depicted system or a system inlet stream entering the depicted system. The product stream may be further processed in a companion chemical processing system or may be commercialized as a final product. The system inlet stream may be a diverted stream from an accompanying chemical treatment system, or may be an untreated feed stream.
Reference will now be made in detail to the various embodiments, some of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts.
Detailed Description
Generally described in this disclosure are examples of mesoporous zeolites, such as mesoporous zeolite Y materials, that may be incorporated into hydroprocessing catalysts, such as hydrocracking catalysts. In some embodiments, a hydrotreating catalyst may be used to crack aromatics in heavy oil in a pretreatment process prior to steam cracking or other cracking processes. The disclosure also relates to methods for producing such mesoporous zeolites and the properties and structure of the mesoporous zeolites produced. According to one or more embodiments, the zeolite Y composition may include mesoporosity. Throughout this disclosure, such zeolitic materials may be referred to as "medium pore zeolites. As used throughout this disclosure, "zeolite" refers to a microporous-containing inorganic material having regular crystalline internal cavities and molecular size channels. The microporous structure of zeolites (e.g., pore sizes of 0.3nm to 1nm) can provide large surface areas and desired size/shape selectivity, which can be advantageous for catalysis. The mesoporous zeolite may comprise an aluminosilicate, titanosilicate, or pure silicate. In embodiments, the zeolite may comprise micropores (present in the microstructure of the zeolite) and additionally mesopores. As used throughout this disclosure, microporous refers to pores in a structure having a diameter of less than or equal to 2nm and greater than or equal to 0.1nm, and mesoporous refers to pores in a structure having a diameter of greater than 2nm and less than or equal to 100nm, or in some embodiments, less than or equal to 50 nm. According to one or more embodiments, the presently described zeolite can be characterized as zeolite Y (i.e., having an aluminosilicate FAU framework type).
As used in this disclosure, "reactor" refers to a vessel in which one or more chemical reactions may occur between one or more reactants, optionally in the presence of one or more catalysts. For example, the reactor may comprise a tank or tubular reactor configured to operate as a batch reactor, a Continuous Stirred Tank Reactor (CSTR), or a plug flow reactor. Exemplary reactors include packed bed reactors such as fixed bed reactors and fluidized bed reactors. One or more "reaction zones" may be provided in the reactor. As used in this disclosure, "reaction zone" refers to a zone in a reactor where a particular reaction occurs. For example, a packed bed reactor having multiple catalyst beds may have multiple reaction zones, where each reaction zone is defined by the area of each catalyst bed.
As used in this disclosure, "separation unit" refers to any separation device or series of separation devices that at least partially separate one or more chemicals that are mixed with each other in a process stream. For example, the separation unit may selectively separate different chemical species from one another to form one or more chemical fractions. Examples of separation units include, but are not limited to, distillation columns, flash tanks, knock-out drums, knock-out pots, centrifuges, filtration devices, traps, scrubbers, expansion devices, membranes, solvent extraction devices, and the like. It should be understood that the separation methods described in this disclosure may not completely separate the entirety of one chemical component from the entirety of another chemical component. It is to be understood that the separation methods described in this disclosure "at least partially" separate different chemical components from each other, and even if not explicitly stated, it is to be understood that separation may comprise only partial separation. As used in this disclosure, one or more chemical components may be "separated" from a process stream to form a new process stream. Generally, a process stream may enter a separation unit and be separated or split into two or more process streams of desired composition. Further, in some separation processes, the "light fraction" and the "heavy fraction" may exit the separation unit, where typically the light fraction stream is lower in boiling point than the heavy fraction stream.
It is to be understood that "reaction effluent" generally refers to the stream that exits a separation unit, reactor, or reaction zone after a particular reaction or separation, and generally has a different composition than the stream entering the separation unit, reactor, or reaction zone.
As used in this disclosure, "catalyst" refers to any substance that increases the rate of a particular chemical reaction. The catalysts described in this disclosure may be used to promote various reactions such as, but not limited to, hydrodemetallization, hydrodesulfurization, hydrodenitrogenation, aromatic cracking, or combinations thereof. As used in this disclosure, "cracking" generally refers to a chemical reaction in which a molecule having carbon-carbon bonds is broken down into more than one molecule by breaking one or more of the carbon-carbon bonds, or converted from a compound containing a cyclic moiety, such as an aromatic, to a compound that does not contain a cyclic moiety, or in which the aromatic moiety is at least partially saturated.
It is understood that two or more process streams are "mixed" or "combined" when two or more lines intersect in the schematic flow diagrams of fig. 1 and 2. Mixing or combining may also comprise mixing by introducing the two streams directly into a similar reactor, separation device, or other system component.
It is to be understood that reactions conducted by catalysts as described in this disclosure may remove chemical constituents from a process stream, such as only a portion of the chemical constituents. For example, a Hydrodemetallization (HDM) catalyst may remove a portion of one or more metals from a process stream, a Hydrodenitrogenation (HDN) catalyst may remove a portion of the nitrogen present in the process stream, and a Hydrodesulfurization (HDS) catalyst may remove a portion of the sulfur present in the process stream. In addition, a hydrocracking catalyst such as one having a Hydrodearomatization (HDA) function can reduce the amount of aromatic moieties in the process stream by cracking those aromatic moieties, including saturation. It should be understood that throughout this disclosure, when a particular catalyst is referred to as having a particular function, the particular catalyst is not necessarily limited in function to the removal or cracking of a particular chemical component or moiety. For example, a catalyst identified in this disclosure as an HDN catalyst may additionally provide hydrocracking functionality, HDA functionality, HDS functionality, or a combination thereof.
It should be further understood that streams may be named according to their components, and that the component that names the stream may be the major component of the stream (e.g., including 50 wt.%, 70 wt.%, 90 wt.%, 95 wt.%, or even 95 wt.% of the content of the stream to 100 wt.% of the content of the stream).
According to an example, mesoporous zeolite Y can be characterized as mesoporous by an average pore size of 2nm to 50 nm. By comparison, conventional zeolites that can be used in hydrocracking catalysts may contain zeolites having micropores, meaning that their average pore diameter is less than 2 nm. In accordance with one or more embodiments, the average pore size of the presently disclosed mesoporous zeolite Y may be from 2nm to 25nm, from 2nm to 20nm, from 2nm to 15nm, from 2nm to 10nm, or from 2nm to 5 nm. In further embodiments, at least 30% of the pore volume may be characterized as mesoporous (i.e., at least 30% of the total pore volume has a pore diameter of at least 2 nm). In further embodiments, at least 35%, 40%, 45%, 50%, 60%, or even 70% of the pore volume may be characterized as mesoporous.
In further embodiments, the mesoporous zeolite Y may have a pore volume of 0.5mL/g to 1.2 mL/g. For example, embodiments of mesoporous zeolite Y can have a pore volume of 0.5mL/g to 0.6mL/g, 0.5mL/g to 0.7mL/g, 0.5mL/g to 0.8mL/g, 0.5mL/g to 0.9mL/g, 0.5mL/g to 1.0mL/g, 0.5mL/g to 1.1mL/g, 0.6mL/g to 1.2mL/g, 0.7mL/g to 1.2mL/g, 0.8mL/g to 1.2mL/g, 0.9mL/g to 1.2mL/g, 1.0mL/g to 1.2mL/g, or 1.1mL/g to 1.2 mL/g. As used in this disclosure, "pore volume" refers to the total pore volume measured.
In further embodimentsThe surface area of the medium pore zeolite Y may be 500m2G to 900m2(ii) in terms of/g. For example, an embodiment of the mesoporous zeolite Y may have a surface area of 500m2G to 550m2/g、500m2G to 600m2/g、500m2G to 650m2/g、500m2G to 700m2/g、500m2G to 750m2/g、500m2G to 800m2/g、500m2G to 850m2/g、550m2G to 900m2/g、600m2G to 900m2/g、650m2G to 900m2/g、700m2G to 900m2/g、750m2G to 900m2/g、800m2G to 900m2Per g, or 850m2G to 900m2/g。
In further embodiments, the crystallinity of the medium pore zeolite can be at least 90%, at least 92%, at least 94%, at least 96%, at least 98%, or even at least 99% of the crystallinity of the initial zeolite material from which the medium pore zeolite can be formed. Higher crystallinity can impart greater stability to the zeolite, particularly when exposed to high temperatures, such as those in heavy oil pretreatment or other catalytic processes. Crystallinity can be measured by XRD (X-ray diffraction). Commercial and relatively good crystalline NaY zeolites (e.g., CBV-100 from Zeolyst) may be referenced at 100% crystallinity. From the XRD spectra, the five strongest peaks were integrated. The sample relative crystallinity is calculated according to the following equation: x (%) 100% × Σ a/Σ a0Wherein A is the sum of the total areas of the five peaks of the sample produced; a. the0Is the sum of the total areas of the five peaks of the reference sample (e.g., CBV-100). Without being bound by theory, it is believed that the combination of hydrothermal or hydrothermal treatment with acid leaching for pore formation may reduce the crystallinity of the zeolite. For example, hydrothermal treatment of a zeolite sample may result in generally less than 90% crystallinity with respect to the starting zeolite.
Without being bound by theory, it is believed that the relatively large pore size (i.e., mesoporosity) of the presently described mesoporous zeolites and hydrocracking catalysts comprising the mesoporous zeolites allows for diffusion of larger molecules within the zeolites, which is believed to increase the reactivity and selectivity of the catalyst. As the pore size increases, the aromatic containing molecules can diffuse more easily into the catalyst and aromatic cracking can increase. For example, in some conventional embodiments, the feedstock converted by the hydroprocessing catalyst can be a vacuum gas oil, a light cycle oil from, for example, a fluid catalytic cracking reactor, or a coker gas oil from, for example, a coker. The molecular sizes in these oils are relatively small relative to those of heavy oils such as crude oil and atmospheric residue, which can be the feedstock for the present process and system. Heavy oils are generally incapable of diffusing within conventional zeolites and are converted at active sites located within the zeolite. Thus, zeolites having larger pore sizes (i.e., for example, mesoporous zeolites) may allow larger molecules of heavy oil to overcome diffusion limitations and may enable reaction and conversion of larger molecules of heavy oil.
The mesoporous zeolitic materials presently described may be prepared by a process comprising reacting a zeolite (e.g., a zeolite that does not contain mesoporosity) with ammonium hexafluorosilicate (NH)4)2SiF6Contacting to modify the framework of the zeolite. After the framework modification step, mesopores can be introduced into the structurally modified zeolite by further processes such as hydrothermal treatment, contact with a base, contact with an acid, or any combination of these. Additional processing steps may include ion exchange of the zeolite prior to framework modification and/or separation of the resulting mesoporous zeolite from other materials by methods such as washing, drying, calcining, and the like.
According to one or more embodiments, the zeolite may be ion-exchanged, such as zeolite Y (i.e., NaY zeolite) including sodium. For example, the zeolite may be reacted with, for example, NH4NO3NH by plasma exchanger4 +And (4) ion exchange. Ion exchange can be carried out at elevated temperatures for a heating time, such as at 90 ℃ (e.g., 70 ℃ to 110 ℃, or 80 ℃ to 100 ℃) for 1 hour (e.g., 30 minutes to 90 minutes, or 45 minutes to 75 minutes). The ion exchange process can produce a zeolite (i.e., NH) that includes sodium and ammonium4NaY zeolite) in which Na is present2The O content may be 2 wt.% to 4 wt.%. The NaY zeolite may contain 10 to 15 wt.% prior to ion exchangeAnd (3) sodium oxide. After ion exchange, the sodium oxide content may be 1 wt.% to 5 wt.%. In some embodiments, the ion exchange may replace the sodium molecules with ammonium molecules. In a further alternative embodiment, the supply may include Na and NH directly4And possibly without the need for an ion exchange step.
According to one or more embodiments, after the ion exchange step, if used, a zeolite (e.g., NH)4NaY zeolite) can be prepared by ammonium hexafluorosilicate ((NH)4)2SiF6) And (4) contacting. In some embodiments, the ammonium hexafluorosilicate may be in an aqueous solution. In further embodiments, the zeolite may be combined with water and heated. For example, deionized water may be added to the NH4NaY zeolite, and the mixture may be heated to an elevated temperature, such as 80-95 ℃. (NH) may be stirred, for example, in deionized water4)2SiF6Aqueous solution with NH4The NaY zeolite was combined dropwise. In one or more embodiments, (NH)4)2SiF6The concentration of the aqueous solution may be 0.2M to 2M. The slurry may be maintained at an elevated temperature, such as 80-95 ℃, for a heating period, such as 1-3 hours.
Ammonium hexafluorosilicate may modify the framework structure of the zeolite to form a framework-modified zeolite material. Without being bound by theory, it is believed that ammonium hexafluorosilicate affects the zeolite structure in several ways. For example, it is believed that NH of aqueous solution4 +And SiF6 -Al cations and Na cations can be removed from the framework simultaneously. Thus, in some embodiments, no further NH is required4 +Ion exchange to reduce the sodium content to meet any specified hydrocracking catalyst specification. It is believed that Na cations, Al cations, or both are present as Na3AlF6Is removed from the zeolite. Additionally, and still not to be bound by theory, it is believed that SiF6 -The Si in (b) may be inserted back into the vacancy left by the Al removal. Thus, it is believed that very high crystallinity (even up to a relative crystallinity of 110%) can be obtained. In addition, it is believed that the zeolite can be made from using ammonium hexafluorosilicate as opposed to other compoundsThe Al is removed uniformly. For example, in some embodiments, the hydrothermal treatment may remove framework Al from the zeolite. However, the hydrothermal treatment may have poor selectivity to remove Al uniformly, resulting in non-uniformity of mesopores. Such hydrothermal treatment may also result in relatively low crystallinity. The mesopores of the mesoporous zeolites described herein can be relatively uniform as observed using TEM (transmission electron microscopy). According to an embodiment, the SiO may be formed by treatment with ammonium hexafluorosilicate2/Al2O3The molar ratio was changed from 4-6 to 6-20.
In accordance with one or more embodiments, the solids and liquids of the slurry containing the framework-modified zeolite may then be at least partially separated, such as by decantation. The top zeolite may be washed with a solvent such as deionized water. The decanted cake may optionally be reacted with e.g. NH at elevated temperature4NO3NH by plasma exchanger4 +Ion exchange for a certain heating period, e.g. at 90 ℃ for 1 hour. The ion exchange cake may then optionally be treated by hydrothermal treatment, such as at 500-600 deg.C, under a steam pressure of 0.1-0.3 MPa for 1-3 hours.
The framework modified zeolite can then be processed to form mesopores. In one or more embodiments, the framework zeolite material can then be combined with one or more of a base or a surfactant. For example, aqueous base (e.g., NaOH, KOH, or ammonium hydroxide) and cetrimide may be combined with the framework modified zeolite to form a mixture. For example, an aqueous base solution may be added to the mixture containing the zeolitic material, and then cetrimide may be subsequently added. In one or more embodiments, the concentration of the aqueous base solution may be 0.05M to 2M, and the weight ratio of cetrimide to zeolite may be 0.1 to 1.5. This second mixture may then be heated to an elevated temperature for a heating period of time to form mesopores in the zeolite material. For example, the elevated temperature may be 100 ℃ to 150 ℃, and the heating period may be 1 day to 5 days. The zeolite material may then be separated from the other contents of the mixture. According to one or more embodiments, the separation may include a solid/liquid separation technique (e.g., centrifugation, filtration, etc.), followed by washing with water, drying at, for example, 100 ℃ for a period of several hours, and then calcining by exposure to a temperature of at least 400 ℃, such as 500 ℃ to 600 ℃, for several hours, such as 3 hours to 6 hours.
In accordance with one or more embodiments, the presently disclosed mesoporous zeolites may be incorporated into a catalyst. The catalyst may be used as a hydrocracking catalyst in the pretreatment of heavy oil, as described in detail later. Likewise, a catalyst comprising a medium pore zeolite is referred to herein as a "hydrocracking catalyst". However, it should be understood that although the hydrocracking catalyst is described in the context of pretreatment (e.g., hydrotreating) of heavy oil, the hydrocracking catalyst described herein may be used for other catalytic reactions of other process fuels.
In one or more embodiments, the hydrocracking catalyst may include the mesoporous zeolite, one or more metal oxide support materials, and one or more metal catalysts described herein. The presently described hydrocracking catalysts may have a material composition that includes from 10 wt.% to 80 wt.% of one or more metal oxide support materials (e.g., alumina), from 18 wt.% to 32 wt.% of a metal catalyst material, and from 10 wt.% to 60 wt.% of a medium pore zeolite.
The metal catalyst material may include one or more metals from IUPAC group 5, 6, 8, 9 or 10 of the periodic table. For example, the hydrocracking catalyst may comprise one or more metals from IUPAC group 5 or 6 and one or more metals from IUPAC group 8, 9 or 10 of the periodic table. For example, the hydrocracking catalyst may comprise molybdenum or tungsten from IUPAC group 6 and nickel or cobalt from IUPAC group 8, 9 or 10. In one or more embodiments, the hydrocracking catalyst may include tungsten and nickel metal catalysts. In another embodiment, the hydrocracking catalyst may include molybdenum and nickel metal catalysts. For example, in one or more embodiments, the hydrocracking catalyst may include 20 to 26 wt.% tungsten sulfide or oxide, 4 to 6 wt.% nickel oxide or sulfide, 10 to 70 wt.% metal oxide support material such as alumina, and 10 to 60 wt.% medium pore zeolite Y. In another embodiment, the hydrocracking catalyst may include 14 to 16 wt.% molybdenum oxide or sulfide, 4 to 6 wt.% nickel oxide or sulfide, 20 to 80 wt.% metal oxide support material such as alumina, and 10 to 60 wt.% medium pore zeolite Y.
The hydrocracking catalyst may be made by providing a medium pore zeolite and impregnating the medium pore zeolite with one or more catalytic metals or by mixing the medium pore zeolite with other components. In one or more embodiments, the mesoporous zeolite, the activated alumina (e.g., boehmite alumina), and the binder (e.g., acid peptized alumina) can be mixed. An appropriate amount of water may be added to form a dough that may be extruded using an extruder. The extrudate can be dried at 80 ℃ to 120 ℃ for 4 hours to 10 hours, and then calcined at 500 ℃ to 550 ℃ for 4 hours to 6 hours. A metal catalyst material, such as Mo, Ni, W or Ni oxide or sulfide, may then be added to this alumina support material containing the mesoporous zeolite. For example, in one or more embodiments, the support material can be impregnated with one or more metals to form a hydrocracking catalyst. According to the described embodiments, impregnation of the support material may include contacting the support material with a solution including one or more metal catalyst precursors. For example, the support material may be immersed in a solution comprising the one or more metal catalyst precursors, the impregnation method sometimes being referred to as saturation impregnation. In the saturated impregnation embodiment, the support may be immersed in an amount of the solution including the metal catalyst precursor of 2 times to 4 times as much as the amount of the metal catalyst precursor absorbed by the support, and then the remaining solution is removed. According to another embodiment, impregnation may be by incipient wetness impregnation, sometimes referred to as capillary impregnation or dry impregnation. In an incipient wetness impregnation embodiment, a solution comprising the metal catalyst precursor is contacted with the support, wherein the amount of solution is approximately equal to the pore volume of the support, and capillary action can draw the solution into the pores. After the support material is contacted with the solution, the support may be calcined at a temperature of at least 500 ℃ (e.g., 500 ℃ to 600 ℃)Bulk material for a period of at least 3 hours (e.g., 3 hours to 6 hours). For example, the calcination may be at a temperature of 500 ℃ for 4 hours. Typically, the impregnation process will allow the metal catalyst to be attached to a support material (i.e., zeolite and metal oxide support). The metal catalyst precursor may comprise one or more of Ni, W, Mo, Co and, after impregnation, is present on the catalyst support as a compound comprising Ni, W, Mo, Co or a combination thereof. When two metal catalysts are desired, two or more metal catalyst precursors may be used. However, some embodiments may contain only one of Ni, W, Mo, or Co. For example, if a W-Ni catalyst is desired, the catalyst support material may be passed through nickel nitrate hexahydrate (i.e., Ni (NO)3)2·6H2O) and ammonium metatungstate (i.e., (NH)4)6H2W12O40) Impregnating the mixture of (1). Although it should be understood that the scope of the present disclosure should not be limited to the selected metal catalyst precursor, other suitable metal catalyst precursors may include cobalt nitrate hexahydrate (Co (NO)3)26H2O), ammonium heptamolybdate ((NH)4)6Mo7O24·4H2O) or ammonium molybdate ((NH)4)2MoO4). After impregnation, the impregnated metal catalyst may be present as a metal oxide, e.g. WO3、MoO3NiO, and CoO, and are referred to in this disclosure as "metal catalyst materials". While these metal catalyst materials may comprise metal oxides, it is to be understood that the metal catalyst materials are different from the metal oxide support material of the catalyst, which in some embodiments may be alumina.
As described herein, the medium pore zeolite can be used as a hydrocracking catalyst in the upgrading process of heavy oils such as crude oil. Such upgrading processes may be a pretreatment step prior to other petrochemical processing, such as a refinery operation utilizing one or more of hydrocracking and fluid catalytic cracking. Generally, the upgrading process can remove at least a portion of one or more of nitrogen, sulfur, and one or more metals from the heavy oil, and can additionally destroy aromatic portions of the heavy oil. According to one or more embodiments, heavy oils may be treated with hydrodemetallization catalysts (sometimes referred to in this disclosure as "HDM catalysts"), transition catalysts, hydrodenitrogenation catalysts (sometimes referred to in this disclosure as "HDN" catalysts), and hydrocracking catalysts. The HDM catalyst, transition catalyst, HDN catalyst and hydrocracking catalyst may be placed in series, or contained in a single reactor, such as a packed bed reactor with multiple beds, or contained in two or more reactors arranged in series.
Referring now to fig. 1, a pretreatment system is schematically depicted comprising one or more of a HDM reaction zone 106, a transition reaction zone 108, a HDN reaction zone 110, and a hydrocracking reaction zone 120. According to embodiments of the present disclosure, the heavy oil feedstream 101 may be mixed with a hydrogen stream 104. The hydrogen stream 104 may include unused hydrogen from the recycled process gas component stream 113, make-up hydrogen from the hydrogen feed stream 114, or both, to form the pre-treated catalyst input stream 105. In one or more embodiments, the pretreated catalyst input stream 105 can be heated to a process temperature of 350 degrees Celsius (C.) to 450℃. The pretreated catalyst input stream 105 may enter and pass through a series of reaction zones, including a HDM reaction zone 106, a transition reaction zone 108, a HDN reaction zone 110, and a hydrocracking reaction zone 120. HDM reaction zone 106 includes HDM catalyst, transition reaction zone 108 includes transition catalyst, HDN reaction zone 110 includes HDN catalyst, and hydrocracking reaction zone 120 includes hydrocracking catalyst including medium pore zeolite.
The described systems and methods are applicable to a variety of heavy oil feeds (in heavy oil feed stream 101), including crude oil, vacuum residuum, tar sands, bitumen, and vacuum gas oil using a catalytic hydrotreating pretreatment process. For example, when the heavy oil feed is crude oil, its American Petroleum Institute (API) gravity can be greater than or equal to 25 degrees, such as 25 degrees to 50 degrees, 25 degrees to 30 degrees, 30 degrees to 35 degrees, 35 degrees to 40 degrees, 40 degrees to 45 degrees, 45 degrees to 50 degrees, or any combination of these ranges. For example, the heavy oil feed used may be an arabian heavy crude oil or an arabian light crude oil. By way of example, typical properties of an arabian heavy crude oil are shown in table 1.
TABLE 1A-Arab heavy-duty Outlet materials
TABLE 1B Arabia light export feedstock
Density, g/ml (20 ℃ C.)
0.8595
API
33.13
C，wt.％
85.29
H，wt.％
12.68
S，wppm
19400
N，wppm
849
Asphaltenes, wt. -%)
1.2
Trace carbon residue, wt. -%)
3.4
V，ppm
15
Ni，ppm
12
As，ppm
0.04
Hg，ppm
<2
Boiling point characteristic
Initial boiling point/5 wt. -%)
33℃/92℃
10wt.％/20wt.％
133℃/192℃
30wt.％/40wt.％
251℃/310℃
50wt.％/60wt.％
369℃/432℃
70wt.％/80wt.％
503℃/592℃
90wt.％/95wt.％
>720℃/>720℃
Final boiling point
>720℃
Yield of narrow cut, wt. -%)
C5-180℃
18wt.％
180-350℃
28.8wt.％
350-540℃
27.4wt.％
>540℃
25.8wt.％
Still referring to fig. 1, a pretreated catalyst input stream 105 may be introduced to a pretreatment reactor 130. According to one or more embodiments, the pretreatment reactor 130 may include a plurality of reaction zones (e.g., the HDM reaction zone 106, the transition reaction zone 108, the HDN reaction zone 110, and the hydrocracking reaction zone 120) arranged in series and each of these reaction zones may include a catalyst bed. In such embodiments, the pretreatment reactor 130 comprises a HDM catalyst bed comprising a HDM catalyst in the HDM reaction zone 106, a transition catalyst bed comprising a transition catalyst in the transition reaction zone 108, a HDN catalyst bed comprising a HDN catalyst in the HDN reaction zone 110, and a hydrocracking catalyst bed comprising a hydrocracking catalyst in the hydrocracking reaction zone 120.
In accordance with one or more embodiments, a pre-treatment catalyst input stream 105 comprising heavy oil is introduced into the HDM reaction zone 106 and contacted with the HDM catalyst. Contacting the HDM catalyst with the pretreatment catalyst input stream 105 can remove at least a portion of the metals present in the pretreatment catalyst input stream 105. After contacting with the HDM catalyst, the pretreated catalyst input stream 105 may be converted to an HDM reaction effluent. The HDM reaction effluent may have a reduced metal content compared to the content of the pretreated catalyst input stream 105. For example, the HDM reaction effluent may have at least 70 wt.% less, at least 80 wt.% less, or even at least 90 wt.% less metal than the pretreatment catalyst input stream 105.
According to one or more embodiments, the weighted average bed temperature of the HDM reaction zone 106 may be 350 ℃ to 450 ℃, such as 370 ℃ to 415 ℃, and the pressure may be 30 bar to 200 bar, such as 90 bar to 110 bar. The HDM reaction zone 106 includes HDM catalyst, and the HDM catalyst may fill the entire HDM reaction zone 106.
The HDM catalyst may include one or more metals from group 5, group 6, or groups 8-10 of the International Union of Pure and Applied Chemistry (IUPAC) of the periodic table. For example, the HDM catalyst may comprise molybdenum. The HDM catalyst may further comprise a support material, and the metal may be disposed on the support material. In one or more embodiments, the HDM catalyst may comprise a molybdenum metal catalyst (sometimes referred to as "Mo/Al") on an alumina support2O3Catalyst "). It should be understood throughout this disclosure that the metals contained in any of the disclosed catalysts may be present as sulfides or oxides or even other compounds.
In one or more embodiments, the HDM catalyst may comprise a metal sulfide on a support material, wherein the metal is selected from the group consisting of: IUPAC group 5, 6, and 8-10 elements of the periodic table, and combinations thereof. The support material may be gamma-alumina or silica/alumina extrudates, spheres, cylinders, beads, pellets and combinations thereof.
In one embodiment, the HDM catalyst may comprise a gamma-alumina support having a surface area of 100m2G to 160m2G (e.g. 100 m)2G to 130m2Per g, or 130m2G to 160m2In terms of/g). HDM catalysts can best be described as having a relatively large pore volume, e.g., at least 0.8cm3In grams (e.g., at least 0.9 cm)3In grams, or even at least 1.0cm3In terms of/g). The pore size of the HDM catalyst may be predominantly macroporous (i.e., greater than 50nm). This can provide a large capacity for metal adsorption on the surface of the HDM catalyst and optionally on the dopant. In one or more embodiments, the dopant may be selected from the group consisting of: boron, silicon, halogen, phosphorus, and combinations thereof.
In one or more embodiments, the HDM catalyst may include 0.5 to 12 wt.% molybdenum oxide or sulfide (e.g., 2 to 10 wt.% or 3 to 7 wt.% molybdenum oxide or sulfide) and 88 to 99.5 wt.% alumina (e.g., 90 to 98 wt.% or 93 to 97 wt.% alumina).
Without being bound by theory, in some embodiments, it is believed that during the reaction in the HDM reaction zone 106, the porphyrins present in the heavy oil are first hydrogenated over a catalyst using hydrogen to produce intermediates. After this primary hydrogenation, the nickel or vanadium present in the center of the porphyrin molecule is reduced with hydrogen and then with hydrogen sulfide (H)2S) is further reduced to the corresponding sulfide. The final metal sulfide is deposited on the catalyst, thereby removing the metal sulfide from the original crude oil. Sulfur is also removed from sulfur-containing organic compounds. This is done in a parallel approach. The rate of these parallel reactions may depend on the sulfur species under consideration. In general, hydrogen is used to extract sulfur, which is converted to H in the process2And S. The remaining sulfur-free hydrocarbon fragments remain in the liquid hydrocarbon stream.
The HDM reaction effluent may pass from HDM reaction zone 106 to transition reaction zone 108 where it is contacted with a transition catalyst. The contacting of the transition catalyst with the HDM reaction effluent may remove at least a portion of the metals present in the HDM reaction effluent stream, and may remove at least a portion of the nitrogen present in the HDM reaction effluent stream. After contact with the transition catalyst, the HDM reaction effluent is converted into a transition reaction effluent. The transition reaction effluent may have a reduced metal content and nitrogen content compared to the HDM reaction effluent. For example, the transition reaction effluent may have at least 1 wt.% less, at least 3 wt.% less, or even at least 5 wt.% less metal content than the HDM reaction effluent. Additionally, the transition reaction effluent may have at least 10 wt.% less, at least 15 wt.% less, or even at least 20 wt.% less nitrogen than the HDM reaction effluent.
According to an embodiment, the weighted average bed temperature of the transitional reaction zone 108 is about 370 ℃ to 410 ℃. The transition reaction zone 108 includes a transition catalyst, and the transition catalyst may fill the entire transition reaction zone 108.
In one or more embodiments, the transition reaction zone 108 may be used to remove an amount of metal components and an amount of sulfur components from the HDM reaction effluent stream. The transition catalyst may comprise an alumina-based support in the form of an extrudate.
In one or more embodiments, the transition catalyst comprises one metal from IUPAC group 6 and one metal from IUPAC groups 8-10. Exemplary IUPAC group 6 metals include molybdenum and tungsten. Exemplary IUPAC group 8-10 metals include nickel and cobalt. For example, the transition catalyst may comprise Mo and Ni (sometimes referred to as "Mo-Ni/Al) on a titania support2O3Catalyst "). The transition catalyst may also contain a dopant selected from the group consisting of: boron, phosphorus, halogen, silicon, and combinations thereof. The surface area of the transition catalyst may be 140m2G to 200m2G (e.g. 140 m)2G to 170m2G or 170m2G to 200m2In terms of/g). The transition catalyst may have a median pore volume of 0.5cm3G to 0.7cm3G (e.g. 0.6 cm)3In terms of/g). The transition catalyst may typically comprise a mesoporous structure having a pore size in the range of 12nm to 50 nm. These properties provide balanced activity in HDM and HDS.
In one or more embodiments, the transition catalyst can include 10 to 18 wt.% molybdenum oxide or sulfide (e.g., 11 to 17 wt.% or 12 to 16 wt.% molybdenum oxide or sulfide), 1 to 7 wt.% nickel oxide or sulfide (e.g., 2 to 6 or 3 to 5 wt.% nickel oxide or sulfide), and 75 to 89 wt.% alumina (e.g., 77 to 87 or 79 to 85 wt.% alumina).
The transition reaction effluent may pass from transition reaction zone 108 to HDN reaction zone 110 where it is contacted with HDN catalyst. Contacting the HDN catalyst with the transition reaction effluent may remove at least a portion of the sulfur and nitrogen present in the transition reaction effluent stream. For example, the HDN catalyst may have HDN and HDS functions. After contacting with the HDN catalyst, the transition reaction effluent may be converted to an HDN reaction effluent. The HDN reaction effluent may have a reduced metal content and nitrogen content compared to the transition reaction effluent. For example, the HDN reaction effluent may have a nitrogen content reduction of at least 80 wt.%, at least 85 wt.%, or even at least 90 wt.% relative to the transition reaction effluent. In another embodiment, the HDN reaction effluent may have a sulfur content reduction of at least 80 wt.%, at least 90 wt.%, or even at least 95 wt.% relative to the transition reaction effluent. In another embodiment, the HDN reaction effluent may have a reduction in aromatics content of at least 25 wt.%, at least 30 wt.%, or even at least 40 wt.% relative to the transition reaction effluent.
According to an embodiment, the weighted average bed temperature of the HDN reaction zone 110 is 370 ℃ to 410 ℃. The HDN reaction zone 110 includes HDN catalyst, and the HDN catalyst may fill the entire HDN reaction zone 110.
In one or more embodiments, the HDN catalyst comprises a metal oxide or sulfide on a support material, wherein the metal is selected from the group consisting of: IUPAC groups 5, 6, and 8-10 of the periodic Table and combinations thereof. The support material may comprise gamma-alumina, mesoporous alumina, silica, or both in the form of extrudates, spheres, cylinders, and pellets.
According to one or more embodiments, the HDN catalyst comprises a gamma alumina-based support having a surface area of 180m2G to 240m2G (e.g. 180 m)2G to 210m2Per g, or 210m2G to 240m2In terms of/g). This relatively large surface area of the HDN catalyst allows for a smaller pore volume (e.g., less than 1.0 cm)3G, less than 0.95cm3In terms of/g, or even less than 0.9cm3In terms of/g). In one or more embodiments, the HDN catalyst contains at least one metal from IUPAC group 6, such as molybdenum, and at least one metal from IUPAC groups 8-10, such as nickel. The HDN catalyst may further comprise at least one dopant selected from the group consisting of:boron, phosphorus, silicon, halogen, and combinations thereof. In one or more embodiments, cobalt may be used to increase the desulfurization of the HDN catalyst. In one or more embodiments, the HDN catalyst has a higher active phase metal loading than the HDM catalyst. This increased metal loading may result in increased catalytic activity. In one or more embodiments, the HDN catalyst includes nickel and molybdenum, and the molar ratio of nickel to molybdenum (Ni/(Ni + Mo)) is from 0.1 to 0.3 (e.g., from 0.1 to 0.2 or from 0.2 to 0.3). In embodiments comprising cobalt, the molar ratio of (Co + Ni)/Mo may be in the range of 0.25 to 0.85 (e.g., 0.25 to 0.5, or 0.5 to 0.85).
According to the examples, HDN catalysts may be produced by mixing a support material, such as alumina, with a binder, such as acid peptized alumina. Water or another solvent may be added to the mixture of carrier material and binder to form an extrudable phase, which is then extruded into a desired shape. The extrudate may be dried at an elevated temperature (e.g., greater than 100 ℃, e.g., 110 ℃) and then calcined at a suitable temperature (e.g., a temperature of at least 400 ℃, at least 450 ℃, e.g., 500 ℃). The calcined extrudate may be impregnated with an aqueous solution containing a catalyst precursor material, such as a precursor material comprising Mo, Ni, or a combination thereof. For example, the aqueous solution may contain ammonium heptamolybdate, nickel nitrate, and phosphoric acid to form an HDN catalyst comprising compounds including molybdenum, nickel, and phosphorus.
In accordance with one or more embodiments, the HDN catalyst may include 10 to 18 wt.% molybdenum oxide or sulfide (e.g., 13 to 17 or 14 to 16 wt.% molybdenum oxide or sulfide), 2 to 8 wt.% nickel oxide or sulfide (e.g., 3 to 7 or 4 to 6 wt.% nickel oxide or sulfide), and 74 to 88 wt.% alumina (e.g., 76 to 84 or 78 to 82 wt.% alumina).
In a similar manner to HDM catalysts, and again without intending to be bound by any theory, it is believed that hydrodenitrogenation and hydrodearomatization may operate by related reaction mechanisms. Both involve some degree of hydrogenation. For hydrodenitrogenation, the organic nitrogen compound is typically in the form of a heterocyclic structure, with the heteroatom being nitrogen. These heterocyclic structures may be saturated prior to removal of the nitrogen heteroatom. Similarly, hydrodearomatization involves the saturation of aromatic rings. Each of these reactions can occur in different amounts on each catalyst type because the catalyst selectively favors one type of transfer over the other, and because the transfer is competitive.
Still referring to fig. 1, the HDN reaction effluent may pass from HDN reaction zone 110 to hydrocracking reaction zone 120, where it contacts the hydrocracking catalyst described above. Contacting the hydrocracking catalyst with the HDN reaction effluent may reduce the level of aromatics present in the HDN reaction effluent. After contacting with the hydrocracking catalyst, the HDN reaction effluent is converted to a pretreated catalyst reaction effluent stream 109. The pretreated catalyst reaction effluent stream 109 may have a reduced aromatic content as compared to the HDN reaction effluent. For example, the pretreated catalyst reaction effluent stream 109 may have at least 50 wt.% less, at least 60 wt.% less, or even at least 80 wt.% less aromatic content than the HDN reaction effluent.
According to one or more embodiments described, the volumetric ratio of HDM catalyst to transition catalyst to HDN catalyst to hydrocracking catalyst may be from 5-20: 5-30: 30-70: 5-30 (e.g., from 5-15: 50-60: 15-20, or about 10:10:60: 20). The ratio of the catalyst may depend at least in part on the metal content of the oil feedstock being processed.
Still referring to fig. 1, the pretreated catalyst reaction effluent stream 109 can enter separation unit 112 and can be separated into a recycle process gas component stream 113 and an intermediate liquid product stream 115. In one or more embodiments, the pretreated catalyst reaction effluent stream 109 can also be purified to remove hydrogen sulfide and other process gases to increase the purity of the hydrogen recycled in the recycle process gas component stream 113. The hydrogen consumed in the process can be compensated by adding fresh hydrogen from the hydrogen feed stream 114, which can be derived from a steam or naphtha reformer or other source. The recycle process gas component stream 113 and the fresh make-up hydrogen feed stream 114 may be combined to form the hydrogen stream 104. In one or more embodiments, the intermediate liquid product stream 115 from the process can be flashed in a flash vessel 116 to separate a light hydrocarbon fraction stream 117 and a pretreated final liquid product stream 118; however, it should be understood that this flashing step is optional. In one or more embodiments, the light hydrocarbon fraction stream 117 serves as recycle and is mixed with the fresh light hydrocarbon diluent stream 102 to produce the light hydrocarbon diluent stream 103. The fresh light hydrocarbon diluent stream 102 may be used to provide make-up diluent to the process as needed to help further reduce deactivation of one or more of the catalysts in the pretreatment reactor 130.
In one or more embodiments, one or more of the pretreated catalyst reaction effluent stream 109, the intermediate liquid product stream 115, and the pretreated final liquid product stream 118 can have a reduced aromatic content as compared to the heavy oil feed stream 101. Additionally, in embodiments, one or more of the pretreated catalyst reaction effluent stream 109, the intermediate liquid product stream 115, and the pretreated final liquid product stream 118 can have a substantially reduced sulfur, metals, asphaltenes, conradson carbon, nitrogen content, or combinations thereof, as well as increased API and increased diesel and vacuum distillate yield as compared to the heavy oil feed stream 101.
In accordance with one or more embodiments, the pretreated catalyst reaction effluent stream 109 can have a nitrogen reduction of at least about 80 wt.%, at least 90 wt.%, or even at least 95 wt.% relative to the heavy oil feed stream 101. According to another embodiment, the pretreated catalyst reaction effluent stream 109 can have a sulfur reduction of at least about 85 wt.%, at least 90 wt.%, or even at least 99 wt.% relative to the heavy oil feed stream 101. According to another embodiment, the pretreated catalyst reaction effluent stream 109 can have at least about a 70 wt.% reduction in aromatic content, at least a 80 wt.% reduction in aromatic content, or even at least a 85 wt.% reduction in aromatic content relative to the heavy oil feed stream 101. According to another embodiment, the pretreated catalyst reaction effluent stream 109 can have at least about 80 wt.% metal reduction, at least 90 wt.% metal reduction, or even at least 99 wt.% metal reduction relative to the heavy oil feed stream 101.
Still referring to fig. 1, in various embodiments, one or more of the pretreated catalyst reaction effluent stream 109, the intermediate liquid product stream 115, and the pretreated final liquid product stream 118 may be suitable for use as an upgraded fuel stream 203 for a refinery process, as shown in fig. 2, as described subsequently in this disclosure. As used in this disclosure, one or more of the pretreated catalyst reaction effluent stream 109, the intermediate liquid product stream 115, and the pretreated final liquid product stream 118 may be referred to as "upgraded fuel" which may be processed downstream by refining, as described with reference to fig. 2.
Referring now to fig. 2, a steam cracking and separation system is depicted. The upgraded fuel stream 203 may be passed to a steam cracker unit 248. The steam cracker unit 248 may comprise a convection zone 250 and a pyrolysis zone 251. The lower boiling fuel fraction stream 203 can be passed into the convection zone 250 along with steam 205. In the convection zone 250, the upgraded fuel stream 203 may be preheated to a desired temperature, such as 400 ℃ to 650 ℃. The contents of the upgraded fuel stream 203 present in the convection zone 250 may then be passed to the pyrolysis zone 251 where it is steam cracked. The steam cracked effluent stream 207 may exit the steam cracker unit 248 and pass through a heat exchanger 208 where a process fluid 209, such as water or pyrolysis fuel oil, cools the steam cracked effluent stream 207 to form a cooled steam cracked effluent stream 210. The steam cracked effluent stream 207 and the cooled steam cracked effluent stream 210 may comprise a mixture of cracked hydrocarbon materials that may be separated into one or more petrochemical products contained in one or more system product streams. For example, the steam cracked effluent stream 207 and the cooled steam cracked effluent stream 210 may comprise one or more of fuel oil, gasoline, mixed butenes, butadiene, propylene, ethylene, methane, and hydrogen, which may be further mixed with water from steam cracking.
In accordance with one or more embodiments, the pyrolysis zone 251 can be operated at a temperature of 700 ℃ to 900 ℃. The pyrolysis zone 251 can operate with a residence time of 0.05 seconds to 2 seconds. The mass ratio of the steam 205 to the upgraded fuel stream 203 may be from about 0.3:1 to about 2: 1.
The cooled steam cracking effluent stream 210 may be separated into a system product stream by separation unit 211. For example, the separation unit 211 may be a distillation column that separates the contents of the cooled steam cracking effluent stream 210 into one or more of a fuel oil stream 212, a gasoline stream 213, a mixed butene stream 214, a butadiene stream 215, a propylene stream 216, an ethylene stream 217, a methane stream 218, and a hydrogen stream 219. As used in this disclosure, the system product streams (e.g., fuel oil stream 212, gasoline stream 213, mixed butene stream 214, butadiene stream 215, propylene stream 216, ethylene stream 217, and methane stream 218) may be referred to as system products, sometimes used as feeds for downstream chemical processing.
In accordance with one or more embodiments, at least about 5 wt.%, 10 wt.%, or even 15 wt.% of the upgraded fuel stream 203 may have a boiling point of 540 ℃ or higher. In conventional systems, such as those that do not include a hydrocracking catalyst including the currently described medium pore zeolite Y, this 540℃ + fraction may need to be removed from the steam cracking process shown in fig. 2 because of excessive coke formation and unsmooth steam cracking operations. However, by using the presently described hydrocracking catalyst including the presently described medium pore zeolite Y, this 540℃ + fraction may be reduced in wt.% in the upgraded fuel stream 203. The steam cracking efficiency is higher due to the reduction of the 540 ℃ + fraction. Without being bound by theory, it is believed that the presence of relatively smaller particle sizes and mesopores in zeolite Y currently described and contained in the hydrocracking catalyst can facilitate better conversion (e.g., aromatics reduction) of the 540℃ + fraction in the heavy oil feed stream 101, as these relatively large molecules (i.e., 540℃ + residue) can access the active sites and thus be converted to a light fraction, which is more readily converted by steam cracking, thereby producing more light olefins.
Examples of the invention
Various embodiments of the process for producing mesoporous zeolite Y will be further illustrated by the following examples. The examples are illustrative in nature and should not be construed as limiting the subject matter of the present disclosure.
Example 1 synthesis of the presently disclosed mesoporous zeolite Y
NaY zeolite and NH4NO3By carrying out NH4 +Ion exchange (at 90 ℃ for 1 hour) to generate NH4NaY zeolite (wherein, Na content is 2-4 wt%). Adding deionized water to NH4NaY zeolite, and heating to 80-90 ℃. Stirring, reacting (NH) for 1-3 hours4)2SiF6Dropping aqueous solution into NH in deionized water4NaY zeolite to form a slurry. The slurry is maintained at 80-95 ℃ for 1-2 hours. The slurry was then decanted. The top zeolite was washed twice with deionized water. Decant cake and NH4NO3By carrying out NH4 +Ion exchange (at 90 ℃ for 1 hour). The ion exchange cake is then optionally treated by hydrothermal treatment at 500-600 deg.C and steam pressure of 0.1-0.3 MPa for 1-3 hours. NaOH and Cetrimide (CTAB) are added to the ion-exchanged and optionally hydrothermally treated cake, with a weight ratio of CTAB/zeolite of 0.1-1.5. The NaOH concentration is in the range of 0.05-2M. The mixture was stirred at room temperature for 4 to 24 hours. After stirring, the mixture was transferred to an autoclave and held at 100 ℃ and 150 ℃ for 1-5 days. After autoclaving, the mixture is separated and washed three times with purified water and dried overnight at 100 ℃ and calcined at 500-600 ℃ for 3-6 hours. To study the different reaction solution pairs (NH)4)2SiF6Influence of solution treatment, also in NH respectively4NO3Aqueous solution and NH4Mesoporous zeolite Y was synthesized under aqueous Cl.
Example 2 characterization of the presently disclosed mesoporous zeolite Y
Mesoporous zeolite Y was synthesized as described in example 1 and studied in the laboratory. The main properties of zeolites are characterized by BET, XRD, etc. Tables 2, 3, 4A, 4B and 5 provide information on the various zeolites formed by the different reaction conditions and compositional variations.
The solution medium (H) is shown in Table 22O、NH4Cl, or NH4NO3) To (NH)4)2SiF6The impact of the treatment. The solution medium is (NH) and4)2SiF6the medium in which the zeolite is present when contacted with, is comprised of4)2SiF6Any medium combined with the zeolite prior to contact, or with (NH) when added to the zeolite4)2SiF6Any medium of mixing. List of "NH4NaY' represents and (NH)4)2SiF6The nature of the zeolite prior to contact.
TABLE 2
As can be seen from the results shown in Table 2, it is derived from NH4Cl and NH4NO3The main properties of the product from using only deionized water as the medium may be more desirable than those of the medium, especially with a lower Na content in the product. Using H2The crystallinity of O is also greater.
Under specific conditions, ultrastable zeolite Y having the properties shown in table 3 was prepared. Specifically, 100g of NH4NaY zeolite (Na 2O: 2.8 wt%) was mixed with 1000ml of deionized water and heated to 80-90 deg.C. 0.8M of (NH) was added dropwise over 3 hours with stirring4)2SiF6Aqueous solution (400 ml). The slurry was maintained at 90-95 ℃ for 2 hours. The slurry was then decanted. The top zeolite was washed twice with deionized water and then dried overnight at 110 ℃ and calcined at 550 ℃ for 4 hours.
TABLE 3
Example 3-preparation and characterization of zeolite Y with and without hydrothermal treatment
In addition, experiments were conducted to measure various properties of the prepared zeolite Y to investigate the effect of hydrothermal treatment during the preparation of mesoporous zeolite. As shown in Table 4A, in (NH)4)2SiF6Prior to treatment, in some samples NH gas was passed under self-generated steam pressure at 550 ℃ and 0.1MPa4 +The exchanged zeolite Y was subjected to hydrothermal treatment for 1 hour. Sample 1 is via NH4 +Commercially available zeolite Y (CBV-100 available from Zeolyst International) was exchanged. Sample 2 represents sample 1 that was subjected to additional hydrothermal treatment as described. Samples 3 and 4 are represented by (NH)4)2SiF6Zeolites of treated samples 1 and 2. In addition, the conditions and comparison results between the various samples are summarized in table 4A.
TABLE 4A
Then, ten grams (dry base) of sample 3 and sample 4 were treated with NaOH alkaline solution and CTAB, respectively. Each of samples 3 and 4 was added to 50ml of 0.1M NaOH aqueous solution and stirred at 60 ℃ for 4 hours. Meanwhile, in another beaker, 2.5g CTAB was mixed with 50ml deionized water and stirred vigorously at room temperature for 4 hours. Then, the CTAB solution was added dropwise to the zeolite slurry, and then stirred at room temperature for 24 hours. The mixture was transferred to a teflon-lined autoclave and treated in an oven at 120 ℃ for 48 hours. After that, the solid product was filtered and washed three times, dried at 120 ℃ overnight, and then calcined at 600 ℃ for 4 hours (rate of temperature rise: 2 ℃/min). As shown in table 4B, the zeolite of sample 3 after treatment with base and CTAB was sample 5, and the zeolite of sample 4 after treatment with base and CTAB was sample 6.
TABLE 4B
Sample name
Sample No. 5
Sample No. 6
Starting zeolite and treatment process
Sample 3+ base + CTAB
Sample 4+ base + CTAB
Surface area, m2/g
896
803
Pore volume, ml/g
0.74
0.96
Average pore diameter, nm
4.6
8.2
The ratio of mesopores in the total pores%
54
75
Example 4 catalyst preparation and testing
In order to compare the reaction performance of catalysts prepared from the currently disclosed medium pore zeolites with those prepared from commercially available zeolites, two catalysts were synthesized.
To make a catalyst comprising the presently disclosed zeolite Y, 22.5g of MoO was added329.2g of Ni (NO)3)2.6H2O, 15.5g of alumina (Puralox HP 14/150 from Sasol, pore volume: 0.9ml/g), and 70g of the mesoporous zeolite of sample 5 of example 3 were added to a mortarIn (b), and then 140.3g of a binder made of acid peptized alumina (Catapal alumina from Sasol, pore volume: 0.5ml/g, IOL: 80 wt%) was added and mixed uniformly. An appropriate amount of water is added to form a dough suitable for extrusion in an extruder. The extrudates were dried at 120 ℃ overnight and calcined at 500 ℃ for 4 hours (rate of temperature rise: 2 ℃/min). The composition of the final catalyst was 15 wt% MoO35 wt% NiO, 50 wt% zeolite and 30 wt% Al2O3. This catalyst is referred to as catalyst a in table 5.
A catalyst having a commercially available zeolite CBV-760(Zeolyst International) was made by: 22.5g of MoO329.2g of Ni (NO)3)2.6H2O, 15.5g of alumina (Puralox HP 14/150 from Sasol, pore volume: 0.9ml/g), and 68g of CBV-600 were added to the mortar and mixed homogeneously. To the mixture was added 140.3g of a binder made of acid peptized alumina (Capapal alumina from Sasol, pore volume: 0.5ml/g, IOL: 80 wt%), and mixed homogeneously. An appropriate amount of water is added to form a dough suitable for extrusion in an extruder. The extrudates were dried at 120 ℃ overnight and calcined at 500 ℃ for 4 hours (rate of temperature rise: 2 ℃/min). The composition of the final catalyst was 15 wt% MoO35 wt% NiO, 50 wt% of commercial zeolite and 30 wt% of Al2O3. This catalyst is referred to as comparative catalyst in table 5.
At a temperature of 390 ℃ for both catalysts, a hydrogen pressure of 150 bar, LHSV 0.2h-1And a hydrogen to oil volume ratio of 1200: 1. The feedstock was hydrotreated arabian light crude oil with HDM/transaction/HDN catalyst system. The feed properties and test results are summarized in table 5. The results show that with a catalyst comprising the presently described zeolite as hydrocracking catalyst, 540 ℃ + residue can be completely converted and the liquid product is a good feedstock for steam cracking.
TABLE 5
Hydrocracking catalyst
Feeding of the feedstock
Catalyst A
Comparative catalyst
Product Properties
Density of
0.8306
0.771
0.7988
S，ppmw
73
230
287.0
N，ppmw
5
<5
3.0
Product yield, wt% FF
C1
0.3
0.4
0.39
C2
0.3
0.6
0.48
C3
0.4
2.1
1.15
nC4
0.1
3.8
1.34
iC4
0.4
2.7
1.38
<180℃
18.4
53.3
30.03
180─350℃
41.4
31.7
45.60
350─540℃
30.5
3.2
15.18
>540℃
8.4
0.0
4.78
It is noted that one or more of the following claims utilize the term "wherein" as a transitional phrase. For the purposes of defining the present technology, it is noted that this term is introduced in the claims as an open transition phrase that is used to introduce a recitation of a series of characteristics of structure, and is to be interpreted in a similar manner as the more commonly used open leading word term "comprising".
It should be understood that any two quantitative values assigned to a characteristic may constitute a range for the characteristic, and all combinations of ranges formed from all the stated quantitative values for a given characteristic are contemplated herein.
It will be apparent to those skilled in the art that various modifications can be made to the described embodiments without departing from the spirit and scope of the claimed subject matter. Thus, it is intended that the present specification cover the modifications and variations of the various embodiments described, provided such modifications and variations come within the scope of the appended claims and their equivalents.
The present disclosure includes one or more non-limiting aspects. A first aspect may comprise a process for preparing a mesoporous zeolite, the process comprising: contacting an initial zeolitic material with ammonium hexafluorosilicate to modify the framework of the initial zeolitic material, forming a framework-modified zeolitic material, the initial zeolitic material comprising silica and alumina and comprising FAU framework-type structures; and forming mesopores in the framework-modified zeolite material.
The second aspect may comprise a method of preparing a catalyst, the method comprising: forming a mesoporous zeolite by a process comprising: contacting an initial zeolitic material with ammonium hexafluorosilicate to modify the framework of the initial zeolitic material, forming a framework-modified zeolitic material, the initial zeolitic material comprising silica and alumina and comprising FAU framework-type structures; and forming mesopores in the framework-modified zeolite material to form a mesoporous zeolite; and admixing the medium pore zeolite with a metal oxide support material and one or more metal catalyst materials to form the catalyst.
Another aspect includes any of the preceding aspects, wherein the initial zeolitic material comprises ammonium and sodium.
Another aspect includes any of the preceding aspects, wherein the initial zeolitic material is formed by ion-exchanging a zeolite comprising sodium with ammonium.
Another aspect includes any of the preceding aspects, wherein forming the mesopores comprises: combining the framework-modified zeolitic material with one or more of a base or a surfactant, cetrimide, to form a mixture; and heating the mixture to an elevated temperature for a heating period of time to form the mesopores.
Another aspect includes any of the preceding aspects, wherein the elevated temperature is from 100 ℃ to 150 ℃, and the heating period is from 1 day to 5 days.
Another aspect includes any of the preceding aspects, wherein the base comprises an aqueous solution comprising one or more of NaO, KOH, or ammonium hydroxide.
Another aspect includes any of the preceding aspects, wherein the surfactant is cetrimide.
Another aspect includes any of the preceding aspects, wherein the separating comprises one or more of washing, drying, or calcining the nano-sized zeolite particles.
Another aspect includes any of the preceding aspects, wherein the ammonium hexafluorosilicate that contacts the initial zeolite is in an aqueous solution.
Another aspect includes any of the preceding aspects, wherein the ammonium hexafluorosilicate is at a concentration of 0.2M to 2.0M.
Another aspect includes any of the preceding aspects, further comprising separating the zeolite comprising mesopores from other contents of the mixture.
Another aspect includes any of the preceding aspects, wherein the medium pore zeolite has a crystallinity of at least 90% relative to the initial zeolite.
Another aspect includes any of the preceding aspects, wherein one or more of the metal catalyst materials comprises a W, Mo, Ni, or Co oxide or sulfide.
Another aspect includes any of the preceding aspects, wherein the catalyst comprises a W oxide or sulfide and a Ni oxide or sulfide.
Another aspect includes any of the preceding aspects, wherein the catalyst comprises Mo and Ni oxides or sulfides.
Another aspect includes any of the preceding aspects, wherein the catalyst comprises: 20 to 26 wt.% of a W oxide or sulfide; 4 to 6 wt.% of a Ni oxide or sulfide; 10 to 60 wt.% of the medium pore zeolite; and 10 to 70 wt.% alumina.
Another aspect includes any of the preceding aspects, wherein the catalyst comprises: 14 to 16 wt.% Mo oxide or sulfide; 4 to 6 wt.% of a Ni oxide or sulfide; 10 to 60 wt.% of the medium pore zeolite; and 20 to 80 wt.% alumina.
Another aspect includes any of the preceding aspects, wherein the metal oxide support material comprises alumina.
Having described the subject matter of the present disclosure in detail and by reference to specific embodiments thereof, it should be noted that the various details disclosed herein are not to be considered as implying that such details relate to elements of the essential components of the various embodiments described herein, even though specific elements are shown in each of the figures accompanying this specification. Rather, the following claims should be looked to in order to provide a unique representation of the breadth of the disclosure and corresponding scope of the various embodiments described herein. Further, it will be apparent that modifications and variations are possible without departing from the scope of the appended claims.
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