Process for converting hydrocarbons to olefins

Abstract

This application relates to a method for converting hydrocarbons in a hydrocarbon stream, comprising contacting the hydrocarbon stream with a steam and a catalyst system under steam-enhanced catalytic cracking conditions to produce an effluent containing olefins. The catalyst system comprises a framework-substituted pentasilicone zeolite. The framework-substituted pentasilicone zeolite has a modified pentasilicone framework. The modified pentasilicone framework comprises a pentasilicaluminosilicate framework, wherein a portion of the skeletal aluminum atoms of the pentasilicaluminosilicate framework is replaced by Ce and Fe atoms. At least a portion of the Fe atoms are monomeric.

Description

Cross-reference to related applications

[0001] This application claims priority to U.S. Application Serial No. 18 / 402,371, filed January 2, 2024, the entire disclosure of which is incorporated herein by reference. Technical Field

[0002] This disclosure generally relates to methods and systems for converting hydrocarbons into olefins. More specifically, this disclosure relates to methods and systems for steam-enhanced catalytic cracking of crude oil to obtain light olefin products. Background Technology

[0003] The growing global demand for high-value-added petrochemical products and chemical intermediates remains a major challenge for many integrated refineries. In particular, the production of valuable light olefins such as ethylene and propylene has attracted increasing attention, as pure olefin streams are considered fundamental units in polymer synthesis. Additionally, light aromatic compounds, such as benzene, toluene, and mixed xylenes, can be used as fuel blending components or converted into high-value-added chemical products and intermediates, serving as fundamental units in chemical synthesis methods. Petrochemical feedstocks (such as crude oil) can be converted into petrochemical products, such as fuel blending components and chemical products and intermediates, such as light olefins and aromatic compounds, which are essential intermediates in much of the petrochemical industry. Crude oil is typically processed through distillation followed by various reforming, solvent treatment, and hydroconversion processes to produce a range of desired fuels, lubricants, chemicals, and feedstocks. Traditional refining systems often combine multiple complex refining units with petrochemical plants to produce high-value-added petrochemical products and intermediates. Summary of the Invention

[0004] Therefore, there is a continued need for cracking catalysts and methods for steam-enhanced catalytic cracking of crude oil feedstocks and other hydrocarbon feedstocks to produce higher yields of light olefins, light aromatic compounds, or both. This disclosure relates to a cracking catalyst comprising a skeleton-substituted pentasilica zeolite catalyst and a method for preparing said skeleton-substituted pentasilica zeolite, the method comprising mixing a pentasilica aluminosilicate framework with an iron precursor and a cerium precursor to form a first mixture, the first mixture being a solid mixture, and calcining the first mixture. The skeleton-substituted pentasilica zeolite may contain monomeric iron, monomeric cerium, or both. This disclosure also relates to methods for converting hydrocarbon feedstocks (e.g., but not limited to crude oil) to produce high-value-added petrochemical products and intermediates, these methods involving steam-enhanced catalytic cracking of the hydrocarbon feedstock in the presence of skeleton-substituted pentasilica zeolite to produce said high-value-added petrochemical products and intermediates, such as, but not limited to, light olefins, light aromatic compounds, or combinations thereof. Compared to other conventional refining methods, the processes and methods of this disclosure can more efficiently convert crude oil and other hydrocarbon feedstocks into high-value-added petrochemical products and intermediates.

[0005] According to at least one aspect of this disclosure, a method for converting hydrocarbons in a hydrocarbon stream may include contacting the hydrocarbon stream with a steam and catalyst system under steam-enhanced catalytic cracking conditions to produce an effluent containing olefins. The catalyst system may comprise a framework-substituted pentasilicone zeolite. The framework-substituted pentasilicone zeolite may have a modified pentasilicone framework. The modified pentasilicone framework may comprise a pentasilicaluminosilicate framework, wherein a portion of the skeletal aluminum atoms of the pentasilicaluminosilicate framework is replaced by Ce and Fe atoms. At least a portion of the Fe atoms may be monomeric.

[0006] Additional features and advantages of various aspects of this disclosure will be set forth in the following detailed description, and those skilled in the art will learn in part from the detailed description or recognize these features and advantages by practicing various aspects of this disclosure.

[0007] Brief description of the attached figures The following specific embodiments of this disclosure can be better understood when read in conjunction with the accompanying drawings, wherein: Figure 1 A general flow diagram of a fixed-bed reactor system for steam catalytic cracking of crude oil to produce olefins and aromatics is schematically depicted according to one or more embodiments shown and described in this disclosure. Figure 2 A flowchart is depicted of a method for producing a cracking catalyst comprising a framework-substituted pentasilica zeolite according to one or more embodiments shown and described in this disclosure; Figure 3 The nitrogen adsorption / desorption spectra of the framework-substituted pentasilica zeolite according to one or more embodiments shown and described in this disclosure are depicted graphically. Figure 4 The pore size distribution of the framework-substituted pentasilica zeolite according to one or more embodiments shown and described in this disclosure is depicted graphically. Figure 5 The UV-Vis diffuse reflectance spectra of skeleton-substituted pentasilicone zeolite according to one or more embodiments shown and described in this disclosure are depicted graphically. Figure 6 The X-ray diffraction (XRD) spectra of a framework-substituted pentasilica zeolite according to one or more embodiments shown and described in this disclosure are depicted graphically. Figure 7 The nitrogen-programmed temperature desorption (NH3-TPD) spectra of a skeleton-substituted pentasil zeolite according to one or more embodiments shown and described in this disclosure are depicted graphically. Figure 8Field emission transmission electron microscopy (FE-TEM) images of each of the skeleton-substituted pentasilica zeolites according to one or more embodiments shown and described in this disclosure are depicted. Figure 9 A general flow diagram of a fixed-bed reactor system for evaluating cracking catalysts is schematically depicted according to one or more embodiments shown and described in this disclosure; Figure 10 The product yields obtained by cracking AXL crude oil with cracking catalysts of CE-A, CE-B and EX-1 according to one or more embodiments shown and described in this disclosure are depicted graphically. Figure 11 The product yields obtained by cracking AXL crude oil with cracking catalysts of CE-C, CE-D, EX-1, EX-2 and EX-3 according to one or more embodiments shown and described in this disclosure are depicted graphically. Figure 12 The product yields obtained by cracking AXL crude oil using cracking catalysts of EX-1, EX-4, EX-5, and EX-6 are graphically depicted according to one or more embodiments shown and described in this disclosure; and Figure 13 The product yields obtained by cracking AXL crude oil with cracking catalysts of CE-C, CE-D, EX-1, EX-2, EX-3 and EX-4 according to one or more embodiments shown and described in this disclosure are depicted graphically.

[0008] When description Figure 1 and Figure 9 When providing a simplified schematic diagram, numerous valves, temperature sensors, electronic controllers, etc., that are compatible with and well-known to those skilled in the art may be omitted. Furthermore, items typically included in, for example... Figure 1 and Figure 9 The systems depicted include auxiliary components such as gas sources, heat exchangers, and buffer tanks. However, those skilled in the art will understand that these components are within the scope of this disclosure.

[0009] in addition, Figure 1 and Figure 9 In the simplified diagram, arrows indicate process flow. However, arrows can also refer to conveyor lines that can transport process flow between two or more system components. Arrows connected to one or more system components indicate inlets or outlets within a given system component, while arrows connected to only one system component indicate system outlet flow leaving the depicted system or system inlet flow entering the depicted system. The direction of the arrows typically corresponds to the primary direction of movement of the process flow or the process flow contained within the physical conveyor lines indicated by the arrows.

[0010] Figure 1 and Figure 9 Arrows in a simplified diagram can also indicate process steps that transfer a process flow from one system component to another. For example, an arrow from a first system component to a second system component can represent the "transfer" of a process flow from the first system component to the second system component. This can include the process flow "exiting" or "removing" from the first system component and the process flow "introducing" into the second system component.

[0011] Reference will now be made to the various aspects in more detail, some of which are shown in the accompanying drawings. Detailed Implementation

[0012] This disclosure relates to cracking catalysts and methods for steam-enhanced catalytic cracking of crude oil to produce higher yields of light olefins, light aromatic compounds, or both. The method for reforming hydrocarbon feedstocks disclosed herein may include contacting the hydrocarbon feedstock with steam in the presence of a cracking catalyst, under reaction conditions sufficient to subject at least a portion of the hydrocarbons in the feedstock to one or more cracking reactions, to produce a steam catalytic cracking effluent comprising light olefins, light aromatic compounds, or both. The cracking catalyst may comprise a skeletal-substituted pentasilica zeolite. The skeletal-substituted pentasilica zeolite may comprise cerium atoms substituted for skeletal aluminum atoms and monomeric iron atoms.

[0013] Framework-substituted pentasilica zeolite can be prepared by combining a pentasilica aluminosilicate framework with an iron precursor and a cerium precursor to form a first mixture; and calcining the first mixture to produce framework-substituted pentasilica zeolite in which the aluminum atoms of the framework are replaced by monomeric iron atoms. Using cracking catalysts incorporating framework-substituted pentasilica zeolite of this disclosure, steam-enhanced catalytic cracking of hydrocarbon feedstocks (e.g., but not limited to crude oil) can improve the selectivity and yield of light olefins, light aromatics, or both with fewer processing steps compared to conventional hydrocarbon refining systems.

[0014] As used in this disclosure, the term "cracking" refers to a chemical reaction in which molecules having carbon-carbon bonds break into more than one molecule through the breaking of one or more carbon-carbon bonds. As used in this disclosure, the term "catalytic cracking" refers to cracking carried out in the presence of a catalyst. Some catalysts may exhibit multiple forms of catalytic activity, and naming a catalyst after a particular function does not imply that the catalyst cannot have catalytic activity for other functions.

[0015] As used in this disclosure, the term "catalyst" refers to any substance that increases the rate of a particular chemical reaction (e.g., but not limited to, cracking).

[0016] As used in this disclosure, the term "used catalyst" refers to a catalyst that has been contacted with reactants under reaction conditions but has not yet been regenerated in a regenerator or regenerated in situ by a regeneration process. "Used catalyst" may have coke deposited on it and may include partially coked catalyst as well as fully coked catalyst. The amount of coke deposited on the "used catalyst" may be greater than the amount of coke remaining on the regenerated catalyst after regeneration. "Used catalyst" may also include catalysts whose temperature is lower after contact with reactants compared to before contact.

[0017] As used in this disclosure, the term "regenerated catalyst" refers to a catalyst that has been contacted with reactants under reaction conditions and then regenerated in a regenerator, or regenerated in situ by a regeneration process, or both, wherein the regeneration process heats the catalyst to a higher temperature, oxidizes it, and removes at least a portion of the coke or other organic contaminants from the catalyst to restore at least a portion of the catalyst's catalytic activity. Compared to used catalyst, a "regenerated catalyst" may have less coke or organic contaminants, a higher temperature, or both, and may have higher catalytic activity. Compared to fresh catalyst that has not been contacted with reactants in the cracking zone and then regenerated, a "regenerated catalyst" may have more coke and lower catalytic activity.

[0018] As used throughout this disclosure, the terms "butene" or "mixed butene" are used interchangeably and refer to one or more combinations of isobutene, 1-butene, trans-2-butene, or cis-2-butene. As used throughout this disclosure, the term "n-butene" refers to one or more combinations of 1-butene, trans-2-butene, or cis-2-butene. As used throughout this disclosure, the term "2-butene" refers to trans-2-butene, cis-2-butene, or combinations thereof.

[0019] As used in this disclosure, the term "initial boiling point" or "IBP" for a composition refers to the temperature at which the component with the lowest boiling point in the composition begins to transition from the liquid phase to the gas phase. As used in this disclosure, the term "final boiling point" or "EBP" for a composition refers to the temperature at which the component with the highest boiling point in the composition transitions from the liquid phase to the gas phase. Hydrocarbon mixtures can be characterized by distillation profiles expressed in terms of boiling point temperatures at which a specific weight percentage of the composition has transitioned from the liquid phase to the gas phase.

[0020] As used in this disclosure, the term "atmospheric boiling point temperature" refers to the boiling point temperature of a compound at atmospheric pressure.

[0021] As used in this disclosure, the terms "crude oil" or "whole crude oil" should be understood to mean a liquid, gas, or mixture of liquids and gases of petroleum that has not undergone significant separation or reaction processes, and in embodiments includes impurities such as, but not limited to, sulfur compounds, nitrogen compounds, and metallic compounds. Crude oil is different from crude oil fractions. In some embodiments, the crude oil feedstock may be a minimally processed light crude oil to provide a crude oil feedstock with a total metal (Ni+V) content of less than 5 parts per million by weight (ppmw) and a Conradson carbon residue of less than 5% by weight.

[0022] As used in this disclosure, the term "direct" means transferring material, such as effluent, from a first component of a processing system to a second component of the same system without passing the material through any intermediate component or unit operation capable of altering the material's composition. Similarly, the term "direct" also means introducing material (e.g., feed) into a component of the processing system without passing the material through any pre-component capable of altering the material's composition. Intermediate or pre-component components or systems capable of altering the material's composition include reactors and separators, but are not typically intended to include heat exchangers, valves, pumps, sensors, or other auxiliary components required for chemical process operation.

[0023] As used in this disclosure, the terms "downstream" and "upstream" refer to the location of a component or unit operation of the processing system relative to the flow direction of the material through the processing system. For example, if the material flowing through the processing system encounters the first component before encountering the second component, the second component is considered to be "downstream" of the first component. Similarly, if the material flowing through the processing system encounters the first component before encountering the second component, the first component is considered to be "upstream" of the second component.

[0024] As used in this disclosure, the term "effluent" refers to a stream that flows out of a reactor, reaction zone, or separator after a particular reaction or separation. Typically, the effluent has a different composition than the stream entering the reactor, reaction zone, or separator. It should be understood that when the effluent is transferred to another component or system, only a portion of the effluent may be transferred. For example, a sidestream stream may carry away some effluent, meaning that only a portion of the effluent may enter a downstream component or system. The terms "reaction effluent" and "reactor effluent" specifically refer to streams flowing out of a reactor or reaction zone.

[0025] The term "residence time" refers to the amount of time that reactants are in contact with a catalyst under reaction conditions, such as reaction temperature.

[0026] The term "light olefins" refers to hydrocarbon compounds containing 2 to 4 carbon atoms and at least one carbon-carbon double bond.

[0027] The term "light aromatic compounds" refers to aromatic compounds with boiling points in the naphtha boiling temperature range of 25°C to 221°C.

[0028] As used in this disclosure, the term "reactor" refers to any container, tank, pipeline, etc., in which one or more chemical reactions (e.g., but not limited to catalytic cracking) can occur between one or more reactants, optionally in the presence of one or more catalysts. One or more "reaction zones" may be provided in the reactor. The term "reaction zone" refers to the space in the reactor where a specific chemical reaction occurs.

[0029] As used in this disclosure, the terms "separation unit" and "separator" refer to any separation device that at least partially separates one or more chemical components in a mixture from each other. For example, a separation system selectively separates different chemical components to form one or more chemical fractions. Examples of separation systems include, but are not limited to, distillation columns, fractionating columns, flash drums, knock-out drums, knock-out pots, centrifuges, decanters, filters, traps, scrubbers, expansion devices, membranes, solvent extraction devices, adsorption devices, chemical separators, crystallizers, chromatographs, precipitators, evaporators, dryers, high-pressure separators, low-pressure separators, or combinations thereof. The separation methods described in this disclosure may not completely separate all of one chemical component from all of another chemical component. Rather, the separation methods described in this disclosure separate different chemical components "at least partially" from each other, and even if not explicitly stated otherwise, separation may involve only partial separation.

[0030] It should also be understood that a stream may be named according to its components, and the components on which the stream is named are typically the major components of the stream (e.g., the components with the largest proportion in the stream after excluding diluting gases such as nitrogen and rare gases). It should also be understood that when a stream containing said components is disclosed as being transferred from one system component to another, the components of the stream are disclosed as being transferred from said system component to another system component. For example, a disclosed “mixed butene stream” transferred to or from a first system component to a second system component should be understood as equivalently disclosing a “mixed butene” transferred to or from a first system component to a second system component.

[0031] Conventional refining systems comprise multiple unit operations. Steam-enhanced catalytic cracking of crude oil can directly reduce the complexity of the refining process, for example, by reducing the number of unit operations required to process crude oil. Steam-enhanced catalytic cracking typically uses zeolites, which generally have a microporous structure with an average pore size of less than 2 nanometers (nm). This disclosure relates to the steam catalytic cracking of crude oil using framework-substituted pentasilica zeolite to convert crude oil into high-value-added hydrocarbon products, such as, but not limited to, light olefins, aromatic compounds, or combinations thereof. In the framework-substituted pentasilica zeolite of this disclosure, a portion of the framework aluminum atoms are replaced by cerium atoms and monomeric iron atoms. This disclosure also relates to framework-substituted pentasilica zeolite and methods for preparing framework-substituted pentasilica zeolite.

[0032] Now for reference Figure 1 The method 100 of this disclosure for converting hydrocarbon feed 102 into light olefins, light aromatic compounds, or both includes contacting hydrocarbon feed 102 with steam in the presence of cracking catalyst 132 under reaction conditions sufficient to subject at least a portion of the hydrocarbons in hydrocarbon feed 102 to one or more cracking reactions to produce a steam catalytic cracking effluent 140 comprising light olefins, light aromatic compounds, or both, wherein cracking catalyst 132 comprises, is composed of, or is substantially composed of a skeletal substituted pentasilicic zeolite.

[0033] Hydrocarbon feed 102 may include one or more heavy oils, such as, but not limited to, crude oil, bitumen, oil sands, shale oil, coal slurry, vacuum residue, tar sands, other heavy oil streams, or combinations thereof. In some embodiments, heavy oil may refer to crude hydrocarbons that have not previously undergone distillation, such as whole crude oil, or may refer to hydrocarbon oils that have undergone some degree of processing before being introduced into method 100 as hydrocarbon feed 102. Hydrocarbon feed 12 may have a density greater than or equal to 0.80 g / mL. Hydrocarbon feed 12 may have a final boiling point (EBP) greater than 565 °C. Hydrocarbon feed 12 may have a nitrogen concentration less than or equal to 3000 parts by weight per million (ppmw).

[0034] In this embodiment, hydrocarbon feed 102 may be crude oil, such as whole crude oil or synthetic crude oil. The crude oil may have an American Petroleum Institute (API) degree of 22 to 50 degrees, such as 22 to 40 degrees, 25 to 50 degrees, or 25 to 40 degrees. For example, hydrocarbon feed 102 may include extra-light crude oil, light crude oil, heavy crude oil, or combinations thereof. In this embodiment, hydrocarbon feed 102 may be light crude oil, such as, but not limited to, Arab Light export crude oil. Exemplary properties of exemplary grades of Arab Light crude oil are provided in Table 1.

[0035] Table 1 - Examples of Light Raw Materials Exported from Arabia

[0036] In this implementation, hydrocarbon feed 102 may be Arab Extra Light (AXL) crude oil. Exemplary boiling point distributions for exemplary grades of AXL crude oil are provided in Table 2.

[0037] Table 2

[0038] When hydrocarbon feed 102 contains crude oil, the crude oil can be pure crude oil or crude oil that has undergone some treatment (e.g., desalting, solids separation, washing). For example, hydrocarbon feed 102 can be desalted crude oil that has undergone a desalting process. In an embodiment, hydrocarbon feed 102 may include crude oil that has not undergone pretreatment, separation (e.g., distillation), or other operations or processes that alter the hydrocarbon composition of the crude oil before it is introduced into system 100.

[0039] In an embodiment, the hydrocarbon feed 102 may be crude oil having a boiling point distribution as described by 5 wt% boiling temperature, 25 wt% boiling temperature, 50 wt% boiling temperature, 75 wt% boiling temperature, and 95 wt% boiling temperature. These corresponding boiling temperatures correspond to the boiling temperatures of a given weight percentage of the hydrocarbon feed stream. In an embodiment, the crude oil may have one or more of the following: a 5 wt% boiling temperature less than or equal to 150°C; a 25 wt% boiling temperature less than or equal to 225°C or less than or equal to 200°C; a 50 wt% boiling temperature less than or equal to 500°C, less than or equal to 450°C, or less than or equal to 400°C; a 75 wt% boiling temperature less than 600°C or less than or equal to 550°C; a 95 wt% boiling temperature greater than or equal to 550°C or greater than or equal to 600°C; or combinations thereof. In the implementation scheme, the crude oil may have one or more of the following: a 5% wt boiling temperature from 0°C to 100°C; a 25% wt boiling temperature from 150°C to 250°C; a 50% wt boiling temperature from 250°C to 400°C; a 75% wt boiling temperature from 350°C to 600°C; and a final boiling point temperature from 500°C to 1000°C, for example, from 500°C to 800°C.

[0040] Refer again Figure 1This document schematically depicts one embodiment of a steam catalytic cracking system 110 for steam catalytic cracking of hydrocarbon feed 102. The steam catalytic cracking system 110 may include at least one steam catalytic cracking reactor 130. The steam catalytic cracking reactor 130 may include one or more fixed-bed reactors, fluidized-bed reactors, batch reactors, fluidized-catalytic cracking (FCC) reactors, moving-bed catalytic cracking reactors, or combinations thereof. In one embodiment, the steam catalytic cracking reactor 130 may be a fixed-bed reactor. In another embodiment, the steam catalytic cracking reactor 130 may include multiple fixed-bed reactors operating in swing mode. The operation of the steam catalytic cracking reactor 130 will be described herein in the context of a fixed-bed reactor. However, it should be understood that other types of reactors, such as fluidized-bed reactors, batch reactors, FCC reactors, or moving-bed reactors, may also be used to contact the hydrocarbon feed 102 with a cracking catalyst for steam catalytic cracking of the methods disclosed herein.

[0041] The steam catalytic cracking reactor 130 can be used to contact the hydrocarbon feed 102 with steam in the presence of the cracking catalyst of this disclosure to produce a steam cracking effluent comprising light olefins, aromatic compounds, or combinations thereof. As previously described, the steam catalytic cracking reactor 130 can be a fixed-bed catalytic cracking reactor, which may include a cracking catalyst 132 disposed within a steam catalytic cracking zone 134. The steam catalytic cracking reactor 130 may include a porous packing material 136, such as silicon carbide packing, upstream of the steam catalytic cracking zone 134. The porous packing material 136 can ensure sufficient heat transfer to the hydrocarbon feed 102 and the steam prior to the steam catalytic cracking reaction in the steam catalytic cracking zone 134.

[0042] Refer again Figure 1 The hydrocarbon feed 102 can be introduced into the steam catalytic cracking reactor 130. In one embodiment, the hydrocarbon feed 102 can be introduced directly into the steam catalytic cracking system 110, for example, by passing the crude oil of the hydrocarbon feed 102 to the steam catalytic cracking reactor 130 without passing the hydrocarbon feed 102 to any separation system or unit operation that alters the hydrocarbon composition of the hydrocarbon feed 102. In another embodiment, the hydrocarbon feed 102 can be treated upstream of the steam catalytic cracking system 110 to remove contaminants, such as, but not limited to, nitrogen compounds, sulfur-containing compounds, heavy metals, or other contaminants that may reduce the effectiveness of the cracking catalyst.

[0043] The methods disclosed herein may include introducing hydrocarbon feed 102 into a steam catalytic cracking system 110, for example, introducing hydrocarbon feed 102 into a steam catalytic cracking reactor 130. Introducing hydrocarbon feed 102 into the steam catalytic cracking reactor 130 may include heating hydrocarbon feed 102 to a temperature of 35°C to 150°C, and then passing hydrocarbon feed 102 into the steam catalytic cracking reactor 130. In embodiments, distillation feed 110 may be heated to 40°C to 150°C, 45°C to 150°C, 50°C to 150°C, 35°C to 145°C, 40°C to 145°C, 45°C to 145°C, 35°C to 140°C, 40°C to 140°C, or 45°C to 140°C.

[0044] In one embodiment, delivering the hydrocarbon feed 102 to the steam catalytic cracking reactor 130 may include delivering the hydrocarbon feed 102 to a feed pump 104, wherein the feed pump 104 may increase the pressure of the hydrocarbon feed 102 and deliver the hydrocarbon feed 102 to the steam catalytic cracking reactor 130. The flow rate of the feed pump 104 may be adjusted such that the hydrocarbon feed 102 is at a rate greater than or equal to 0.1 / h (h -1 ) or greater than or equal to 0.25 h -1 The gas hourly space velocity (GHSV) is injected into the steam catalytic cracking reactor 130. The hydrocarbon feed 102 can be less than or equal to 50 h⁻¹. -1 Less than or equal to 25 h -1 Less than or equal to 20 h -1 Less than or equal to 14 h -1 9 h or less -1 or less than or equal to 5 h -1 The gas hourly space velocity (GHSV) is injected into the steam catalytic cracking reactor 130. Hydrocarbon feed 102 can be injected via feed inlet line 106 at a rate of 0.1 h⁻¹. -1 Up to 50 h -1 0.1 h -1 Up to 25 hours -1 0.1 h -1 Up to 20 h -1 0.1 h -1 up to 14 hours -1 0.1 h -1 up to 9h -1 0.1 h -1 Up to 5 hours -1 0.1 h -1 up to 4 hours -1 0.25 h -1 Up to 50 h -1 0.25 h -1 Up to 25 hours -1 0.25 h -1 Up to 20 h -1 0.25 h-1 up to 14 hours -1 0.25 h -1 up to 9 h -1 0.25 h -1 Up to 5 hours -1 0.25 h -1 up to 4 hours -1 1 h -1 Up to 50 h -1 1h -1 Up to 25 hours -1 1 h -1 Up to 20 h -1 1 h -1 up to 14 hours -1 1 h -1 up to 9 h -1 or 1 hour -1 Up to 5 hours -1 The gas hourly space velocity (GSLV) is injected into the steam catalytic cracking reactor 130. Before injecting the hydrocarbon feed 102 into the steam catalytic cracking reactor 130, the hydrocarbon feed 102 can be further preheated to a temperature of 100°C to 250°C in the feed inlet line 106.

[0045] Water 120 can be injected into the steam catalytic cracking reactor 130 via feedwater pump 124 and feedwater line 122. Feedwater line 122 can be preheated to heat the water 120 to temperatures of 50°C to 175°C, 50°C to 150°C, 60°C to 175°C, or 60°C to 170°C. The water 120 can be converted into steam in feedwater line 122 or upon contact with the hydrocarbon feed 102 in the steam catalytic cracking reactor 130. The flow rate of feedwater pump 124 can be adjusted to pump water 120 (liquid, steam, or both) at a rate greater than or equal to 0.1 h⁻¹. -1 ≥0.5 h -1 1 h or more -1 5 h or more -1 6 h or more -1 10 h or more -1 or even greater than or equal to 15 h -1 The gas hourly space velocity (HWHV) is delivered to the steam catalytic cracking reactor 130. The water 120 can be less than or equal to 100 hWHV. -1 Less than or equal to 75 h -1 Less than or equal to 50 h -1 Less than or equal to 30 h -1 or less than or equal to 20 h -1 The gas hourly space velocity (GHSV) is introduced into the steam catalytic cracking reactor 130. Water 120 can be introduced at a speed of 0.1 h⁻¹. -1 Up to 100 h -10.1h -1 Up to 75 h -1 0.1 h -1 Up to 50 h -1 0.1 h -1 Up to 30 h -1 0.1 h -1 Up to 20 h -1 1 h -1 Up to 100 h -1 1 h -1 Up to 75h -1 1 h -1 Up to 50 h -1 1 h -1 Up to 30 h -1 or 1 hour -1 Up to 20 h -1 The gas hourly space velocity is introduced into the steam catalytic cracking reactor 130.

[0046] Steam injected from water 120 into the steam catalytic cracking reactor 130 can reduce hydrocarbon partial pressure, which can have the dual effect of increasing the yield of light olefins (e.g., ethylene, propylene, and butene) and reducing coke formation on the cracking catalyst. Without being bound by any particular theory, it is believed that light olefins such as propylene and butene are primarily produced by catalytic cracking reactions following a carbocation mechanism, and since these are intermediate products, they can undergo secondary reactions such as hydrogen transfer and aromatization (leading to coke formation). Steam can increase the yield of light olefins by suppressing these secondary bimolecular reactions and can reduce the concentrations of reactants and products, which is beneficial for selectivity towards light olefins. Steam can also suppress secondary reactions that lead to coke formation on the catalyst surface, which is beneficial for maintaining high average catalyst activity. These factors may suggest that a larger steam-to-oil weight ratio may be beneficial for the production of light olefins.

[0047] The mass flow rate of water 120 to the steam catalytic cracking reactor 130 can be less than the mass flow rate of hydrocarbon feed 102 to the steam catalytic cracking reactor 130. In an embodiment, the mass flow rate ratio of water 120 to hydrocarbon feed 102 introduced into the steam catalytic cracking reactor 130 can be less than 1, for example, less than or equal to 0.9, less than or equal to 0.8, less than or equal to 0.7, or less than or equal to 0.6. In the implementation scheme, the mass flow ratio of water 120 introduced into the steam catalytic cracking reactor 130 to the hydrocarbon feed 102 can be 0.2 to less than 1, 0.2 to 0.9, 0.2 to 0.8, 0.2 to 0.7, 0.2 to 0.6, 0.3 to less than 1, 0.3 to 0.9, 0.3 to 0.8, 0.3 to 0.7, 0.3 to 0.6, 0.4 to less than 1, 0.4 to 0.9, 0.4 to 0.8, 0.4 to 0.7, 0.4 to 0.6, 0.5 to less than 1, 0.5 to 0.9, 0.5 to 0.8, 0.5 to 0.7, or 0.5 to 0.6. In another implementation scheme, the mass flow ratio of water 120 introduced into the steam catalytic cracking reactor 130 to the hydrocarbon feed 102 can be approximately 0.5. Water can be present as steam in the steam catalytic cracking reactor 130.

[0048] Refer again Figure 1 The steam catalytic cracking system 110 is capable of contacting hydrocarbon feed 102 with steam (from water 120) in a steam catalytic cracking reactor 130 in the presence of a cracking catalyst under reaction conditions sufficient to cause at least a portion of the hydrocarbons in the hydrocarbon feed 102 to undergo one or more cracking reactions, to produce a steam catalytic cracking effluent 140 comprising light olefins, light aromatic compounds, or both. In an embodiment, the steam catalytic cracking effluent 140 may comprise light olefins, which may include, but are not limited to, ethylene, propylene, butene, or combinations thereof. In an embodiment, the steam catalytic cracking effluent 140 may comprise light aromatic compounds, which are compounds containing an aromatic ring structure and having 10 or fewer carbon atoms. The light aromatic compounds in the steam catalytic cracking effluent 140 may include, but are not limited to, benzene, toluene, ethylbenzene, xylene, or other light aromatic compounds.

[0049] The steam catalytic cracking reactor 130 can operate at temperatures greater than 450°C, greater than 475°C, greater than 500°C, greater than or equal to 525°C, greater than or equal to 550°C, greater than or equal to 575°C, or even greater than or equal to 600°C. The steam catalytic cracking reactor 130 can also operate at temperatures less than or equal to 800°C, less than or equal to 750°C, less than or equal to 700°C, or even less than or equal to 675°C. The steam catalytic cracking reactor 130 can operate at temperatures ranging from 525°C to 800°C, 525°C to 750°C, 525°C to 700°C, 525°C to 675°C, 550°C to 750°C, 550°C to 700°C, 575°C to 675°C, 575°C to 700°C, 575°C to 675°C, 600°C to 750°C, 600°C to 700°C, or 600°C to 675°C. In one embodiment, the steam catalytic cracking reactor 130 can operate at approximately 675°C. The method can be operated at pressures from 1 bar (100 kPa) to 5 bar (500 kPa), for example, from 1 bar (100 kPa) to 4 bar (400 kPa), from 1 bar (100 kPa) to 3 bar (300 kPa), from 1 bar (100 kPa) to 2 bar (200 kPa) or any subrange thereof.

[0050] The method disclosed herein may include contacting a hydrocarbon feed 102 with steam (water 120) in a steam catalytic cracking reactor 130 in the presence of a cracking catalyst 132 for a residence time sufficient to convert at least a portion of the hydrocarbon compounds in the hydrocarbon feed 102 into light olefins, light aromatic compounds, or both. In embodiments, the method may include contacting the hydrocarbon feed 102 with steam (water 120) in the steam catalytic cracking reactor 130 in the presence of the cracking catalyst 132 for a residence time of 0.5 seconds to 1000 seconds, for example, 0.5 seconds to 500 seconds, 0.5 seconds to 250 seconds, 0.5 seconds to 100 seconds, 1 second to 60 seconds, for example, 1 second to 30 seconds, 1 second to 10 seconds, or about 10 seconds.

[0051] When the steam catalytic cracking reactor 130 is a fixed-bed reactor, it can be operated in a semi-continuous manner. For example, during a conversion cycle, the steam catalytic cracking reactor 130 can operate for a period of time with hydrocarbon feed 102 and water 120 flowing into it. After this period, the cracking catalyst can be regenerated. Each conversion cycle of the steam catalytic cracking reactor 130 can be 2 to 24 hours, 2 to 20 hours, 2 to 16 hours, 2 to 12 hours, 2 to 10 hours, 2 to 8 hours, 4 to 24 hours, 4 to 20 hours, 4 to 16 hours, 4 to 12 hours, 4 to 10 hours, or 4 to 8 hours, after which the feed pump 104 and feedwater pump 124 are shut off to stop the flow of hydrocarbons and steam to the steam catalytic cracking reactor 130.

[0052] At the end of the conversion cycle, the flow of hydrocarbon feed 102 and water 120 can be stopped, and the cracking catalyst 132 can be regenerated during the regeneration cycle. In an embodiment, the steam catalytic cracking system 110 may include multiple fixed-bed steam catalytic cracking reactors 130, which may operate in parallel or in series. In an embodiment, the steam catalytic cracking system 110 may include 1, 2, 3, 4, 5, 6, or more than 6 steam catalytic cracking reactors 130, which may operate in series or in parallel. In the case of multiple steam catalytic cracking reactors 130 operating in parallel, one or more steam catalytic cracking reactors 130 can remain in the conversion cycle while one or more other steam catalytic cracking reactors 130 are cut offline to regenerate the nano-zeolite cracking catalyst 132, thereby maintaining the continuous operation of the steam catalytic cracking system 110.

[0053] Refer again Figure 1 During the regeneration cycle, the steam catalytic cracking reactor 130 can be operated to regenerate the cracking catalyst 132. The cracking catalyst 132 can be regenerated to remove coke deposits accumulated during the conversion cycle. To regenerate the cracking catalyst 132, hydrocarbon gases and liquid products generated by the steam catalytic cracking process can be discharged from the steam catalytic cracking reactor 130. Nitrogen gas can be introduced into the steam catalytic cracking reactor 130 through gas inlet line 112 to discharge hydrocarbon gases and liquid products from the fixed-bed steam catalytic cracking reactor 130. Nitrogen gas can be supplied at a rate of 10 h⁻¹. -1 Up to 100 h -1 The gas hourly space velocity is introduced into the steam catalytic cracking reactor 130.

[0054] After venting the hydrocarbon gas and liquid, it can be discharged through gas inlet pipeline 112 at a rate of 10 h. -1 Up to 100 h -1Air is introduced into the steam catalytic cracking reactor 130 at a gas hourly space velocity (GHSV). The air exits the steam catalytic cracking reactor 130 through the air outlet line 142. While air is being passed through the cracking catalyst 132 in the steam catalytic cracking reactor 130, the temperature of the reactor 130 can be raised to a regeneration temperature of 650°C to 750°C over a period of 3 to 5 hours. The gas generated from the air regeneration through the cracking catalyst 132 can be discharged from the steam catalytic cracking reactor 130 and analyzed by an online gas analyzer to detect the presence or concentration of carbon dioxide generated from the decoking of the cracking catalyst 132. Once the carbon dioxide concentration in the gas discharged from the steam catalytic cracking reactor 130 decreases to less than 0.05% to 0.1% by weight, as determined by the online gas analyzer, the temperature of the steam catalytic cracking reactor 130 can be reduced from the regeneration temperature back to the reaction temperature. The airflow through the gas inlet line 112 can be stopped. Nitrogen gas can be introduced into the cracking catalyst 132 for 15 to 30 minutes to remove air from the steam catalytic cracking reactor 130. After nitrogen treatment, the flow of hydrocarbon feed 102 and water 120 can be restored to begin another conversion cycle of the steam catalytic cracking reactor 130. Although described herein in the context of a fixed-bed reactor system, it should be understood that the steam catalytic cracking reactor 130 can be of different types of reactors, such as a fluidized-bed reactor, a moving-bed reactor, a batch reactor, an FCC reactor, or a combination thereof.

[0055] Refer again Figure 1 The steam catalytic cracking effluent 140 can exit the steam catalytic cracking reactor 130. The steam catalytic cracking effluent 140 may include one or more products and intermediates, such as, but not limited to, light hydrocarbon gases, light olefins, aromatic compounds, pyrolysis oil, or combinations thereof. The light olefins in the steam catalytic cracking effluent 140 may include ethylene, propylene, butene, or combinations thereof.

[0056] As previously described, the cracking catalyst comprises a framework-substituted pentasilica zeolite. In embodiments, the cracking catalyst comprises, is composed of, or is substantially composed of a framework-substituted pentasilica zeolite. In embodiments, the cracking catalyst may comprise a framework-substituted pentasilica zeolite catalyst in which Ce and monomeric Fe are substituted into the zeolite framework to replace skeletal aluminum atoms. The cracking catalyst does not have any other catalytic species impregnated into, deposited on the surface of, or otherwise incorporated into the framework-substituted pentasilica zeolite.

[0057] Now for reference Figure 2, A method 200 for preparing a framework-substituted pentasil zeolite may include providing a starting pentasil zeolite having an aluminosilicate framework, such as ZSM-5 zeolite, in step 202; in step 204, combining the starting pentasil zeolite having an aluminosilicate framework with a metal precursor to form a first mixture; in step 206, mixing and / or grinding the first mixture; in step 208, calcining the first mixture; thereby forming a framework-substituted pentasil zeolite, as shown in step 210.

[0058] The starting pentasil zeolite may be a shape-selective zeolite having the activity of catalytically cracking hydrocarbons to produce smaller hydrocarbon molecules, such as light olefins, light aromatics, or both. Suitable pentasil zeolites may include ZSM-5 zeolite. As used in this disclosure, "ZSM-5" refers to a zeolite having the MFI framework type according to the IUPAC zeolite nomenclature and composed of silica and alumina. ZSM-5 refers to "Zeolite Socony Mobil-5" and is a pentasil family zeolite, which may be represented by the chemical formula Na n Al n Si 96–n O 192 ·16H2O, where 0 < n < 27. In an embodiment, the aluminosilicate framework of the starting pentasil zeolite may have a microporous pore structure with an average pore diameter less than or equal to 2 nm. The starting pentasil zeolite may have a silica-to-alumina molar ratio greater than or equal to 10 or greater than or equal to 20. The starting pentasil zeolite may have a silica-to-alumina molar ratio less than or equal to 300, such as less than or equal to 200, less than or equal to 100, or even less than or equal to 4 or. In an embodiment, the starting pentasil zeolite may have a silica-to-alumina molar ratio of 10 to 300, 10 to 200, 10 to 100, 10 to 50, 20 to 300, 20 to 200, 20 to 100, 20 to 50, or 50 to 300. The starting pentasil zeolite may be in the form of multiple particles, such as multiple spherical particles.

[0059] The starting pentasilica zeolite with an aluminosilicate framework is then combined with a metal precursor to form a first mixture. The metal precursor may include a cerium (Ce) precursor and an iron (Fe) precursor. The Ce precursor may include any compound or family of compounds containing Ce that generates Ce ions when exposed to high temperatures (e.g., greater than 500°C) during calcination. Suitable Ce precursors may include, but are not limited to, Ce-acetylacetonates (e.g., Ce(ACAC)2), Ce-nitrates, Ce-chlorides, or combinations thereof. The Fe precursor may include any compound or family of compounds containing Fe that generates Fe ions when exposed to high temperatures (e.g., greater than 500°C) during calcination. Suitable Fe precursors may include, but are not limited to, Fe-acetylacetonates (e.g., Fe(ACAC)2), Fe-nitrates, Fe-chlorides, or combinations thereof. Based on the total weight of the first mixture, the first mixture may contain at least 80% by weight, at least 90% by weight, at least 95% by weight, at least 99% by weight, at least 99% by weight, or even 100% by weight of the starting pentasilica zeolite, the cerium precursor, and the iron precursor.

[0060] The first mixture can be blended to produce a relatively homogeneous solid mixture. In an embodiment, the first mixture can be blended in a grinder or using a mortar and pestle. The first mixture can be blended until it has a uniform appearance. The first mixture can be a dry solid mixture. In an embodiment, the first mixture may contain less than 5% by weight, less than 1% by weight, or even less than 0.1% by weight of a solvent (e.g., water or an organic solvent).

[0061] The first mixture can be calcined to form a framework-substituted pentasilica zeolite. The first mixture can be calcined in an oxidizing atmosphere (e.g., air). The first mixture can be calcined at a temperature of at least 500°C, for example at least 525°C, at least 550°C, 500°C to 700°C, 500°C to 600°C, 500°C to 575°C, 525°C to 700°C, 525°C to 600°C, 525°C to 575°C, or any subrange thereof. Without being theoretically limited, it is believed that calcination of the first mixture can lead to the substitution of Ce and Fe precursor atoms for the framework aluminum atoms of the starting pentasilica zeolite.

[0062] Framework-substituted pentasilica zeolites may contain cerium atoms that replace a portion of the skeletal aluminum atoms that originally constitute the aluminosilicate framework of the starting pentasilica. The cerium atoms may be monomeric or oligomeric. Monomeric cerium atoms may be in the form of cerium cations, such as Ce. 3+ Ce 4+Or both. The oligomeric cerium atoms can be in the form of cerium oxides, such as CeO2, Ce2O3, or both. In embodiments, the cerium atoms can be predominantly monomeric. In embodiments, at least 40%, at least 60%, at least 80%, at least 90%, at least 95%, or even at least 99% of the cerium atoms in the framework-substituted pentasilica zeolite can be monomeric cerium atoms. The ratio of monomeric cerium atoms to oligomeric cerium atoms can be determined by, for example, UV-Vis spectroscopy. Based on the total weight of the framework-substituted pentasilica zeolite, the framework-substituted pentasilica zeolite may contain greater than 0% by weight and less than or equal to 1.0% by weight of cerium atoms. In the implementation scheme, based on the total weight of the framework-substituted pentasilica zeolite, the framework-substituted pentasilica zeolite may contain greater than 0.8% by weight and less than or equal to 0.8% by weight, greater than 0.6% by weight and less than or equal to 0.4% by weight, greater than 0.3% by weight and less than or equal to 0.3% by weight, 0.1 to 1.0% by weight, 0.2% to 1.0% by weight, 0.2% to 0.8% by weight, 0.2% to 0.6% by weight, 0.2% to 0.4% by weight, 0.2% to 0.3% by weight, 0.1% to 0.3% by weight, about 0.2% by weight, or any subrange thereof of cerium atoms.

[0063] Framework-substituted pentasilica zeolites may contain iron atoms that replace a portion of the skeletal aluminum atoms that originally constitute the aluminosilicate framework of the starting pentasilica zeolite. The iron atoms can be monomeric or oligomeric. Monomeric iron atoms can be in the form of iron cations, such as Fe. 2+ Fe 3+ Fe 4+ Or combinations thereof. The oligomeric iron atoms may be in the form of iron oxides, such as FeO2, Fe2O3, or combinations thereof. In embodiments, the iron atoms may be predominantly monomeric. In embodiments, at least 40%, at least 60%, at least 80%, at least 90%, at least 95%, or even at least 99% of the iron atoms in the framework-substituted pentasilica zeolite may be monomeric. The ratio of monomeric iron atoms to oligomeric iron atoms can be determined by, for example, UV-Vis spectroscopy. Based on the total weight of the framework-substituted pentasilica zeolite, the framework-substituted pentasilica zeolite may contain at least 0.2 wt% iron atoms. In embodiments, based on the total weight of the framework-substituted pentasilica zeolite, the framework-substituted pentasilica zeolite may contain at least 0.4 wt% iron atoms, for example, 0.2 wt% to 1.0 wt%, 0.2 wt% to 0.8 wt%, 0.2 wt% to 0.6 wt%, 0.4 wt% to 1.0 wt%, 0.4 wt% to 0.8 wt%, 0.4 wt% to 0.6 wt%, about 0.5 wt%, or any subrange thereof.

[0064] The weight ratio of cerium to iron can be from 1:5 to 5:5. In the embodiments, the ratio of cerium to iron can be from 1:5 to 4:5, 1:5 to 3:5, 1:5 to 2:5, 2:5 to 5:5, 2:5 to 4:5, 2:5 to 3:5, about 2:5 or any subrange thereof.

[0065] The substituted pentasilica zeolite, after substitution, can have a silica to alumina molar ratio greater than or equal to 10 or greater than or equal to 20. The substituted pentasilica zeolite can also have a silica to alumina molar ratio less than or equal to 300, for example, less than or equal to 200, less than or equal to 100, or even less than or equal to 40. In embodiments, the substituted pentasilica zeolite can have a silica to alumina molar ratio of 10 to 300, for example, 10 to 200, 10 to 100, 10 to 50, 20 to 300, 20 to 200, 20 to 100, 20 to 50, or 50 to 300.

[0066] The framework-substituted pentasilica zeolite can be in the form of multiple particles. In embodiments, the framework-substituted pentasilica zeolite can have an average crystal size greater than or equal to 50 nm, greater than or equal to 100 nm, or even greater than or equal to 200 nm. The framework-substituted pentasilica zeolite can also have an average crystal size less than or equal to 600 nm or less than or equal to 500 nm. In embodiments, the framework-substituted pentasilica zeolite can have an average crystal size of 50 nm to 600 nm, 50 nm to 500 nm, 100 nm to 600 nm, 100 nm to 500 nm, 200 nm to 600 nm, or 200 nm to 500 nm. The average crystal size is determined by scanning electron microscopy (SEM) according to known methods.

[0067] In the implementation scheme, the framework-substituted pentasilicone zeolite may have a 200 m 2 / g to 600 m 2 / g, for example 200 m 2 / g to 500 m 2 / g、200 m 2 / g to 400 m 2 / g、300 m 2 / g to 600 m 2 / g、300 m 2 / g to 500 m 2 / g、300 m 2 / g to 400m 2 / g、325 m 2 / g to 375 m 2Specific surface area per gram or any subrange thereof. Specific surface area is determined according to the Brunauer-Emmett-Teller (BET) method. Throughout this disclosure, specific surface area may be referred to as BET surface area.

[0068] Framework-substituted pentasilica zeolite can have a concentration of 0.1 cubic centimeters per gram (cm³). 3 / g) to 0.60 cm 3 / g, for example 0.1 cm 3 / g to 0.5 cm 3 / g, 0.1 cm 3 / g to 0.4 cm 3 / g, 0.1 cm 3 / g to 0.3 cm 3 / g, 0.1 cm 3 / g to 0.2 cm 3 / g, 0.15 cm 3 / g to 0.6 cm 3 / g, 0.15 cm 3 / g to 0.4 cm 3 / g, 0.15 cm 3 / g to 0.2 cm 3 / g, 0.16 cm 3 / g to 0.19 cm 3 / g, or approximately 0.179 cm 3 The total pore volume was determined by modeling and analysis using nonlocal density functional theory (NLDFT) from measured gas adsorption isotherms. The BET method was also used to determine the total pore volume.

[0069] In embodiments, the framework-substituted pentasilica zeolite may not contain any heteroatoms substituted into the zeolite framework, except for cerium and iron atoms. Heteroatoms substituted into the zeolite framework refer to elements, such as metals or metalloids, that substitute for silicon, aluminum, or both in the zeolite framework. In embodiments, the cracking catalyst may include framework-substituted pentasilica zeolite without any other catalytic species impregnated or deposited on the surface or in the pores of the framework-substituted pentasilica zeolite, except for cerium and iron atoms substituted into the zeolite framework. In embodiments, the framework-substituted pentasilica zeolite may be substantially free of impregnated metals, metalloids, or oxides thereof, for example, having less than or equal to 0.01% by weight of impregnated metals, metalloids, or oxides thereof based on the total weight of the framework-substituted pentasilica zeolite. The presence of impregnated metals, metalloids, or oxides thereof can alter the catalytic properties of the framework-substituted pentasilica for converting crude oil to light olefins, light aromatics, or both via steam catalytic cracking. The cracking catalyst may comprise individual particles of framework-substituted pentasilica zeolite with an average particle size of 150 micrometers (μm) to 200 μm. In embodiments, the cracking catalyst may consist of or be substantially composed of framework-substituted pentasilica zeolite. In embodiments, the cracking catalyst does not include any binder, matrix material, or other catalytic species supported on the framework-substituted pentasilica zeolite. In embodiments, the cracking catalyst may comprise at least 10 wt%, at least 20 wt%, 10 wt% to 100 wt%, 10 wt% to 15 wt%, 15 wt% to 20 wt%, 20 wt% to 30 wt%, 30 wt% to 40 wt%, 40 wt% to 50 wt%, 50 wt% to 75 wt%, 75 wt% to 100 wt%, or any combination thereof of framework-substituted pentasilica zeolite within these ranges. In embodiments, the balance of the cracking catalyst may comprise a balanced catalyst (ECAT).

[0070] Refer again Figure 1 The steam catalytic cracking system 110 may further include a cracking effluent separation system 150 disposed downstream of the steam catalytic cracking reactor 130. When the steam catalytic cracking system 110 includes multiple steam catalytic cracking reactors 130, the steam catalytic cracking effluent 140 from each steam catalytic cracking reactor 130 can be transferred to a single shared cracking effluent separation system 150. In an embodiment, each steam catalytic cracking reactor 130 may have its own dedicated cracking effluent separation system 130. The steam catalytic cracking effluent 140 can be transferred directly from the steam catalytic cracking reactor 130 to the cracking effluent separation system 150. The cracking effluent separation system 150 can separate the steam catalytic cracking effluent 140 into one or more cracking product effluents, which may be liquid or gaseous product effluents.

[0071] Refer again Figure 1 The cracking effluent separation system 150 may include one or more separation units. These separation units may include, but are not limited to, distillation columns, fractionators, flash tanks, separators, centrifuges, decanters, filters, traps, scrubbers, expansion devices, membranes, solvent extraction devices, adsorption devices, chemical separators, crystallizers, chromatographs, precipitators, evaporators, dryers, high-pressure separators, low-pressure separators, or combinations thereof. The separation units may include one or more gas-liquid separators, one or more liquid-liquid separators, or combinations thereof.

[0072] In an embodiment, the cracking effluent separation system 150 may include a gas-liquid separation unit 160 and a centrifuge unit 170 downstream of the gas-liquid separation unit 160. The gas-liquid separation unit 160 may be used to separate steam catalytic cracking effluent 140 into a liquid effluent 162 and a gaseous effluent 164. The gas-liquid separation unit 160 may be used to reduce the temperature of the steam catalytic cracking effluent 140 to condense components in the steam catalytic cracking effluent 140 having five or more carbon atoms. The gas-liquid separation unit 160 may operate at a temperature of 10°C to 15°C to ensure that n-pentane and components with boiling points higher than n-pentane condense into the liquid effluent 162. The liquid effluent 162 may include distilled fractions (e.g., naphtha, kerosene, gas oil, vacuum gas oil), unconverted feedstock, residue, water, or combinations thereof. Liquid effluent 162 may include light aromatic compounds produced in steam catalytic cracking reactor 130, including but not limited to benzene, toluene, mixed xylenes, ethylbenzene, and other light aromatic compounds. Liquid effluent 162 may include at least 95%, at least 98%, at least 99%, or even at least 99.5% of the hydrocarbon component having 5 or more carbon atoms in steam catalytic cracking effluent 140. Liquid effluent 162 may include at least 95%, at least 98%, at least 99%, or even at least 99.5% of water from steam catalytic cracking effluent 140.

[0073] Gaseous effluent 164 may include olefins, such as ethylene, propylene, butene, or combinations thereof; light hydrocarbon gases, such as methane, ethane, propane, n-butane, isobutane, or combinations thereof; other gases, such as, but not limited to, hydrogen; or combinations thereof. Gaseous effluent 164 may include C2-C4 olefin products generated in steam catalytic cracking reactor 130, such as, but not limited to, ethylene, propylene, butene (1-butene, cis-2-butene, trans-2-butene, isobutene, or combinations thereof) or combinations thereof. Gaseous effluent 164 may include at least 90%, at least 95%, at least 98%, at least 99%, or at least 99.5% of C2-C4 olefins from steam catalytic cracking effluent 140. Gaseous effluent 164 may be passed to a downstream gas separation system (not shown) to further separate gaseous effluent 164 into various product streams, such as, but not limited to, one or more olefin product streams.

[0074] In one embodiment, a liquid effluent 162 comprising water and hydrocarbons having more than five carbon atoms can be fed into an in-line centrifuge unit 170. The in-line centrifuge unit 170 can be used to separate the liquid effluent 162 into a liquid hydrocarbon effluent 172 and an aqueous effluent 174. The in-line centrifuge unit 170 can operate at speeds of 2500 rpm to 5000 rpm, 2500 rpm to 4500 rpm, 2500 rpm to 4000 rpm, 3000 rpm to 5000 rpm, 3000 rpm to 4500 rpm, or 3000 rpm to 4000 rpm to separate the hydrocarbon phase from the aqueous phase.

[0075] Liquid hydrocarbon effluent 172 may include hydrocarbons having five or more carbon atoms from steam catalytic cracking effluent 140. Liquid hydrocarbon effluent 172 may include light aromatic compounds produced in steam catalytic cracking reactor 130, including but not limited to benzene, toluene, mixed xylenes, ethylbenzene, and other light aromatic compounds. Liquid hydrocarbon effluent 172 may also include naphtha, kerosene, diesel oil, vacuum gas oil (VGO), or combinations thereof. Liquid hydrocarbon effluent 172 may include 90%, at least 95%, at least 98%, at least 99%, or even at least 99.5% of the hydrocarbon component from liquid effluent 162. Liquid hydrocarbon effluent 172 may be passed to downstream processing for further conversion or separation. At least a portion of liquid hydrocarbon effluent 172 may be returned to steam catalytic cracking reactor 130 for further conversion to olefins. Aqueous effluent 174 may include water and water-soluble components from liquid effluent 162. Aqueous effluent 174 may include some dissolved hydrocarbons soluble in the aqueous phase of liquid effluent 162. Aqueous effluent 174 may include at least 95%, at least 98%, at least 99%, or even at least 99.5% of the water from liquid effluent 162. Aqueous effluent 174 may be passed to one or more downstream processes for further treatment. In an embodiment, at least a portion of aqueous effluent 174 may be returned to steam catalytic cracking reactor 130 as at least a portion of the water 120 introduced into steam catalytic cracking reactor 130.

[0076] In embodiments, the skeleton-substituted pentasilica zeolite produced by the previously described method can be used as a catalyst in a fluidized bed catalytic cracking (FCC) reactor. The FCC reactor can be a fluidized bed reactor. In the FCC reactor, a cracking catalyst comprising, consisting of, or substantially consisting of the skeleton-substituted pentasilica zeolite can be contacted with a hydrocarbon feedstock such as crude oil in the presence of steam to produce light olefins, light aromatic compounds, or combinations thereof. Suitable FCC methods for the catalytic cracking of crude oil in the presence of steam are disclosed in U.S. Patent Application Nos. 17 / 009,008, 17 / 009,012, 17 / 009,020, 17 / 009,022, 17 / 009,039, 17 / 009,048, and 17 / 009,073, all of which are incorporated herein by reference in their entirety. The hydrocarbon feedstock can be any hydrocarbon feedstock previously discussed in this disclosure. An FCC reactor can be an upflow or downflow FCC reactor. An FCC reactor system may include one or more FCC reactors with one or more catalyst regenerators.

[0077] In the implementation scheme, the FCC reactor can operate at a reaction temperature of at least 450°C, such as at least about 500°C, 500°C to 800°C, 550°C to 800°C, 600°C to 800°C, 650°C to 800°C, 450°C to 750°C, 500°C to 750°C, 550°C to 750°C, 600°C to 750°C, 650°C to 750°C, 500°C to 700°C, 550°C to 700°C, 600°C to 700°C, or 650°C to 700°C. Steam can be injected into the FCC reactor. The hydrocarbon feedstock can be catalytically cracked in the presence of steam containing skeletal-substituted pentasilica zeolite. The mass ratio of steam to hydrocarbons in an FCC reactor can be 0.2 to 0.8, 0.3 to 0.8, 0.4 to 0.8, 0.5 to 0.8, 0.2 to 0.7, 0.3 to 0.7, 0.4 to 0.7, 0.5 to 0.7, 0.2 to 0.6, 0.3 to 0.6, 0.4 to 0.6, 0.5 to 0.6, or approximately 0.5. Steam can refer to all water in the FCC reactor. In the implementation scheme, the residence time of the hydrocarbon feed and vapor in contact with the cracking catalyst in the FCC reactor can be 0.5 seconds to 1000 seconds, 0.5 seconds to 500 seconds, 0.5 seconds to 250 seconds, 0.5 seconds to 100 seconds, 0.5 seconds to 60 seconds, 0.5 seconds to 20 seconds, 1 second to 20 seconds, 2 seconds to 20 seconds, 5 seconds to 20 seconds, 8 seconds to 20 seconds, 1 second to 18 seconds, 2 seconds to 18 seconds, 5 seconds to 18 seconds, 8 seconds to 18 seconds, 1 second to 16 seconds, 2 seconds to 16 seconds, 5 seconds to 16 seconds, 8 seconds to 16 seconds, 1 second to 14 seconds, 2 seconds to 14 seconds, 5 seconds to 14 seconds, 8 seconds to 14 seconds, 1 second to 12 seconds, 2 seconds to 12 seconds, 5 seconds to 12 seconds, or 8 seconds to 12 seconds. In the implementation scheme, the weight ratio of cracking catalyst to hydrocarbons (catalyst to oil) in the FCC reactor can be 3 to 40, for example 3 to 30, 3 to 20, 5 to 40, 5 to 30, 5 to 20, 5 to 10, 7 to 40, 7 to 30, 7 to 20, 10 to 40, 10 to 30, 10 to 20, or 20 to 40. The cracking effluent from the FCC reactor can be separated into various product streams, intermediate streams, and aqueous streams in a separation system downstream of the FCC reactor.

[0078] Example The following examples will further illustrate various aspects of this disclosure. These examples are illustrative in nature and should not be construed as limiting the subject matter of this disclosure.

[0079] Example CE-A: Preparation of Comparative Cracking Catalyst A In Example CE-A, a comparative cracking catalyst was prepared according to the initial wet impregnation method. Specifically, 5 g of HZSM-5 powder (CBV3024E, silica / alumina ratio of 30, purchased from Zeolyst International) was loaded into a 250 mL round-bottom flask equipped with a magnetic stirrer. The flask was then immersed in a 25°C water bath, and the powder was continuously stirred. Separately, a 10 mL precursor solution was prepared by dissolving 31 mg of cerium(III) nitrate hexahydrate and 180.9 mg of ferric(III) nitrate nonahydrate in deionized water. The precursor solution was then slowly added to the round-bottom flask. After the solution addition was complete, the slurry was vigorously stirred for 3 hours. The resulting material was then slowly dried on a hot plate at 50°C, followed by drying overnight at 100°C. The dried powder was then ground and subsequently calcined in air at a heating rate of 5°C / min for 5 hours in a furnace at 550°C.

[0080] Example CE-B: Preparation of Comparative Cracking Catalyst B In Example CE-B, a comparative framework-substituted pentasilica zeolite was prepared according to a liquid ion exchange method. Specifically, a 100 mL precursor solution was prepared by dissolving 309.9 mg of cerium(III) nitrate hexahydrate and 1808.6 mg of ferric(III) nitrate nonahydrate in deionized water and heating the solution to 80°C. Then, 5 g of HZSM-5 powder was slowly added to the solution, and the solution was stirred for 2 hours. The sample was filtered, washed with deionized water, and then dried overnight in an oven at 110°C. The dried powder was ground and then calcined in air at a heating rate of 5°C / min for 5 hours in a furnace at 550°C.

[0081] Example EX-1: Preparation of Exemplary Cracking Catalyst EX-1 In Example EX-1, the framework-substituted pentasilica zeolite of this disclosure was prepared according to the solid-state ion exchange (SSIE) method. Specifically, 5 g of HZSM-5 powder was mixed with 31 mg of cerium(III) nitrate hexahydrate and 180.9 mg of ferric(III) nitrate nonahydrate and thoroughly ground in an agate mortar for 1 hour under ambient conditions. The resulting mixture was calcined in air at a heating rate of 5 °C / min in a furnace at 550 °C for 5 hours to produce the cracking catalyst of Example EX-1. The composition of the EX-1 catalyst is provided in Table 3.

[0082] Example EX-2: Preparation of cracking catalyst EX-2 In Example EX-2, a framework-substituted pentasilica zeolite was prepared according to the same method described for producing the catalyst in EX-1. For example, in EX-2, Fe (ferric(III) nitrate nonahydrate) was first added. The catalyst was calcined as described in EX-1. After the first calcination, Ce (cerium(III) nitrate hexahydrate) was added. The catalyst was calcined again as described in EX-1. The composition of the EX-2 catalyst is provided in Table 3.

[0083] Example EX-3: Preparation of cracking catalyst EX-3 In Example EX-3, a framework-substituted pentasilica zeolite was prepared according to the same method described for producing the catalyst in EX-1. For example, in EX-3, Ce (cerium(III) nitrate hexahydrate) was first added. The catalyst was calcined as described in EX-1. After the first calcination, Fe (ferric(III) nitrate nonahydrate) was added. The catalyst was calcined again as described in EX-1. The composition of the EX-3 catalyst is provided in Table 3.

[0084] Examples EX-4 to EX-6: Preparation of cracking catalysts 4 to 6 In each of Examples EX-4 to EX-6, a framework-substituted pentasilica zeolite was prepared according to the same method as in EX-1. However, the Ce and Fe concentrations were adjusted, and the compositions of the catalysts in EX-4, EX-5, and EX-6 are provided in Table 3.

[0085] Example CE-C: Preparation of Comparative Cracking Catalyst C In Example CE-C, a comparative framework-substituted pentasilica zeolite was prepared according to the same method as in EX-1. However, Fe was not used.

[0086] Example CE-D: Preparation of Comparative Cracking Catalyst D In Example CE-D, a comparative framework-substituted pentasilica zeolite was prepared according to the same method as in EX-1. However, Ce was not used.

[0087] Table 3

[0088] Catalyst formation efficiency As shown in Table 4, the efficiency of the impregnation process is calculated. Table 4 shows that this method (used for the production of EX-1) is more efficient than the initial wet process used for the production of CE-A in terms of utilizing cerium and iron precursors.

[0089] Table 4

[0090] The utilization efficiency of the zeolite precursor was calculated. The results are shown in Table 5. As shown in Table 5, this method (for the production of EX-1) is more efficient than the wet impregnation method used for the production of CE-A in utilizing the ZSM-5 precursor.

[0091] Table 5

[0092] UV-Vis characterization To investigate the composition of different Ce and Fe species present in the precursor solution, UV-vis diffuse reflectance spectroscopy was performed using known testing methods. Figure 5 As shown, the matrix HZSM-5 exhibits absorption bands at approximately 210 and 280 nm. No distinguishable peaks for cerium oxide species were found in any of the zeolite samples, indicating that all cerium in the samples is either monomeric or present at concentrations undetectable by UV-Vis diffuse reflectance spectroscopy.

[0093] Samples CE-A and CE-B showed absorption signals for both oligomeric Fe species (~237 nm) and monomeric Fe species (>290 nm), indicating the formation of both monomeric and oligomeric Fe species. However, the spectrum of EX-1 only showed the absorption signal of monomeric Fe (~237 nm) and did not show the absorption signal of oligomeric Fe (>290 nm).

[0094] Catalyst physical characterization The amounts of Ce and Fe species on the prepared catalyst were measured by inductively coupled plasma mass spectrometry (ICP-MS) using known methods, and the results are presented in Table 6.

[0095] Figure 3 The N2 adsorption-desorption isotherms and pore size distributions of the ZSM-5 zeolite matrix, CE-A, CE-B, and EX-1 were plotted. The isotherms of all catalysts were Type I, reflecting their uniform microporous structure. Regardless of the preparation method, the isotherm shape and pore size distribution did not change significantly after cerium and iron modification. The adsorption-desorption isotherms were obtained at low relative pressures (p / p...). o The overlap of approximately 0.4 indicates monolayer-multilayer adsorption. The initiation of the hysteresis loop indicates capillary condensation within the pores, while the filling of the pores corresponds to the end of the hysteresis loop. Loading Ce and Fe metals using solid-state ion exchange resulted in a slight decrease in specific surface area, while the porosity and pore volume increased due to the infiltration of metal species into the support. However, other preparation methods showed comparable surface areas and porosities, indicating that metal modification has a limited impact on the physicochemical properties of the ZSM-5 catalyst matrix (Table 5).

[0096] Table 6

[0097] X-ray diffraction (XRD) was performed on each of the above samples according to known testing methods. The XRD spectra of each sample are shown below. Figure 6 In the study, all samples CE-A, CE-B, and EX-1 exhibited diffraction patterns similar to those of the unmodified zeolite, showing a typical ZSM-5 structure at 2θ = 7–10° and 20–24°, and without additional metal oxide phases, indicating a high dispersion of Ce and Fe species in all samples. It was observed that the XRD crystallinity of the zeolite remained almost identical even after changes in the preparation method.

[0098] Ammonia-programmed temperature desorption (NH3-TPD) was performed on each sample. The NH3-TPD spectra are shown below. Figure 7 The results are summarized in Table 7. The NH3-TPD spectrum of the initial ZSM-5 showed two distinct peaks at approximately 271 °C and 532 °C, corresponding to the weak and strong acid sites, respectively. The total acidity of sample CE-A was 0.365 mmol / g, approximately 15% of the acidity of the initial HZSM-5 (0.318 mmol / g) (Table 8). Samples CE-B and EX-1 exhibited slightly lower temperatures and acidities, particularly at the weak acid sites, due to the uniform distribution of monomeric Ce and Fe species on the zeolite support.

[0099] Table 7

[0100] Field emission scanning electron microscopy (FESEM) and energy-dispersive X-ray spectroscopy (EDS) revealed that the framework-substituted ZSM-5 zeolite of Example EX-1 consisted of a mixture of large microcrystals and a small number of small particles. EDS analysis of selected regions on the framework-substituted ZSM-5 zeolite of Example EX-1 showed that the elements Si, Al, O, Ce, and Fe were uniformly dispersed. This indicates that the elements within the framework are uniformly distributed on the framework surface of the framework-substituted ZSM-5 zeolite.

[0101] like Figure 8 As shown, high-resolution transmission electron microscopy (HR-TEM) images of each sample were captured. (a) and (b) are images of CE-A. (c) and (d) are images of CE-B. (e) and (f) are images of EX-1. From Figure 8 As can be seen, each of samples CE-A, CE-B, and EX-1 contains discrete particles of approximately 200 nm in size and an ordered microporous structure. The images show that while all three samples retain an ordered microstructure, EX-1 (f) retains a linearly ordered microstructure.

[0102] Evaluation of cracking catalysts The framework-substituted pentasilica zeolites CE-A, CE-B, and EX-1 were blended with a balanced catalyst (E-Cat) to form catalytic mixtures. E-Cat refers to a physical mixture of fresh and regenerated or aged catalysts, which is circulated within the FCC reactor. The ratio of E-Cat to framework-substituted pentasilica zeolite was 75 wt% E-Cat and 25 wt% framework-substituted pentasilica zeolite. Each catalytic mixture was hydrothermally deactivated at 810°C in 100% steam for 6 hours prior to activity testing.

[0103] The catalytic mixture was evaluated at atmospheric pressure in a fixed-bed reaction (FBR) system used for steam catalytic cracking of crude oil such as AXL crude. The general composition of AXL crude is provided in Table 8. Gas and liquid products from the cracking were characterized by offline gas chromatography (GC) analysis using simulated distillation and naphtha analysis techniques.

[0104] Now for reference Figure 9 The FBR system 300 used for evaluating cracking catalysts is schematically depicted. AXL crude oil 301 is supplied to a fixed-bed reactor 340 using metering pump 311. A constant feed rate of 2 g / h for AXL crude oil 301 is used. Water 302 is supplied to the fixed-bed reactor 340 using metering pump 312. Water 302 is preheated using preheater 321. A constant feed rate of 1 g / h for water 302 is used. Nitrogen 303 is used as a carrier gas at a rate of 65 mL / min. Nitrogen 303 is supplied to the fixed-bed reactor 340 using a mass flow controller (MFC) 313. Nitrogen 303 is preheated using preheater 322. Water 302 and nitrogen 303 are mixed using mixer 330 and the mixture is introduced into the fixed-bed reactor 340. AXL crude oil 301, water 302, and nitrogen 303 are preheated to 250°C in preheating zone 342 before entering the reactor tubes. The preheating zone 342 is preheated using a line heater 331. Crude oil 301 is introduced from the top of reactor 240 through injector 341 and mixed with steam in the top two-thirds of reactor tube 340 before reaching catalyst bed 344.

[0105] The catalyst bed 344 in reactor tube 340 is moved downwards by a few centimeters to allow more time for preheating of AXL crude oil 301 before contact with the cracking catalyst in catalyst bed 344. For each experiment, 1 gram (g) of cracking catalyst with a size of 30-40 mesh is placed in the center of reactor tube 340, supported by silica wool 343, 346 and reactor insert 345. Silica wool 343, 346 is placed at the bottom and top of catalyst bed 344 to hold it in place. The height of catalyst bed 344 is 1-2 cm. In different experiments, a catalytic mixture containing CE-A, CE-B and EX-1 is used as the cracking catalyst, respectively.

[0106] After steam deactivation, crude oil hydrocarbon feed and water / steam are introduced into the FBR reactor tube. The reaction is allowed to proceed for 45–60 minutes until steady state is reached. The mass ratio of steam to crude oil is 0.5 g steam per gram of crude oil. The crude oil is cracked at a cracking temperature of 675 °C and a catalyst-to-crude oil weight ratio of 1:2. The residence time of crude oil and steam in the fixed-bed reactor 340 is 10 seconds. The total run time for each individual experiment is 5 hours.

[0107] The cracking product stream 345 is introduced into a gas-liquid separator 351. A wet test meter 352 is placed downstream of the gas-liquid separator 351. The gaseous products 361 and liquid products 362 of the cracking reaction are characterized by offline gas chromatography (GC) analysis using simulated distillation and naphtha analysis techniques. The yields of ethylene, propylene, and butene from the cracking reaction product stream are analyzed. Yield analysis is plotted on... Figure 10 The values ​​are provided in numerical form in Table 8.

[0108] Table 8: Impact of Loading Method

[0109] AXL achieved the highest AXL conversion (83.3%), the highest maximum conversion of naphtha fraction (72%), and the lowest coke yield (5.2%) in steam-enhanced catalytic cracking on EX-2. Furthermore, CE-A exhibited the highest yield of light olefins. Therefore, the experimental results confirm that this catalyst and its preparation method yielded optimal catalytic performance. Unrestricted by theory, it is believed that this is because the solvent-free solid-state ion exchange (SSIE) method avoids the preparation of the precursor solution and the drying process of solvent removal. This prevents the hydrolysis and subsequent aggregation of Ce and Fe monomers in the precursor solution and during drying, resulting in EX-1 having the highest proportion of active Ce and Fe species.

[0110] The catalyst evaluation experiments described above were repeated using comparative examples CE-C, CE-D, and Examples EX-1 to EX-6. The results are shown in... Figure 11 , Figure 12 and Figure 13 As can be seen from the figure, simultaneous loading of Ce and Fe provided the best yield. Furthermore, 0.2 wt% Ce and 0.5 wt% Fe provided the best activity and yield at the tested concentrations.

[0111] In a first aspect, a method for converting hydrocarbons in a hydrocarbon stream may include: contacting the hydrocarbon stream with a steam and a catalyst system under steam-enhanced catalytic cracking conditions to produce an effluent containing olefins, wherein: the catalyst system may contain a framework-substituted pentasilicone zeolite; the framework-substituted pentasilicone zeolite may have a modified pentasilicone framework, the modified pentasilicone framework may contain a pentasilicaluminosilicate framework, wherein a portion of the skeletal aluminum atoms of the pentasilicaluminosilicate framework may be substituted with Ce atoms and Fe atoms; and at least a portion of the Fe atoms may be monomeric.

[0112] In a second aspect, in conjunction with the first aspect, at least a portion of the Ce atoms may be monomeric.

[0113] In a third aspect, in conjunction with aspect 1 or 2, based on the total mass of the skeleton-substituted pentasilica zeolite, calculated on an oxide basis, the skeleton-substituted pentasilica zeolite may contain 0.2 wt% to 1.0 wt% Ce atoms and 0.2 wt% to 0.5 wt% Fe atoms.

[0114] In the fourth aspect, in conjunction with any of aspects 1 to 3, the ratio of Ce atoms to Fe atoms can be from 1:5 to 3:5.

[0115] In a fifth aspect, in conjunction with any one of aspects 1 to 4, the framework-substituted pentasilica zeolite may have: (a) 200 m 2 / g to 600 m 2 (a) Specific surface area per g; (b) Molar ratio of SiO2 to Al2O3 from 10 to 200; and (c) 0.1 cm 3 / g to 0.6 cm 3 / g pore volume.

[0116] In the sixth aspect, in conjunction with any one of aspects 1 to 5, at least 80 mol% of the said Ce atoms may be monomeric.

[0117] In the seventh aspect, in conjunction with aspect 6, at least 99 mol% of the stated Ce atoms may be monomeric.

[0118] In the eighth aspect, in conjunction with any one of aspects 1 to 7, at least 80 mol% of the Fe atoms may be monomeric.

[0119] In the ninth aspect, in conjunction with aspect 8, at least 99 mol% of the Fe atoms may be monomers.

[0120] In a tenth aspect, in conjunction with any one of aspects 1 to 9, the steam-enhanced catalytic cracking conditions may include a steam-to-hydrocarbon ratio of 0.2 to 0.8.

[0121] In the eleventh aspect, in conjunction with any one of aspects 1 to 10, the steam-enhanced catalytic cracking conditions may include a reaction temperature of 450°C to 750°C, a reaction pressure of 1 bar to 5 bar, and a residence time of 0.5 seconds to 1000 seconds.

[0122] In the twelfth aspect, in conjunction with any one of aspects 1 to 11, the framework-substituted pentasilica zeolite can be prepared by a solid-state ion exchange method, wherein solid-state ion exchange is used to replace the framework aluminum atoms with Ce and Fe atoms.

[0123] In the thirteenth aspect, in conjunction with aspect 12, the framework aluminum atoms can be simultaneously replaced by solid-state ion exchange Ce and Fe atoms.

[0124] In the fourteenth aspect, in conjunction with any one of aspects 1 to 13, the catalyst system may comprise particles with a particle size of 150 μm to 200 μm.

[0125] In the fifteenth aspect, in conjunction with any one of aspects 1 to 14, the hydrocarbon stream may comprise crude oil.

[0126] In a sixteenth aspect, in conjunction with any one of aspects 1 to 15, the framework-substituted pentasilica zeolite may be prepared by a method comprising the steps of: combining a pentasilica aluminosilicate framework with an iron precursor and a cerium precursor to form a first mixture; and calcining the first mixture to form the framework-substituted pentasilica zeolite.

[0127] In the seventeenth aspect, in conjunction with aspect 16, calcining the first mixture may include exposing the first mixture to air at a temperature of at least 500°C for at least 1 hour.

[0128] In the eighteenth aspect, in conjunction with any of aspects 16 to 17, the first mixture may be a dry mixture.

[0129] In the nineteenth aspect, in conjunction with any one of aspects 1 to 18, the effluent may contain at least 46% by weight of light olefins.

[0130] In a twentieth aspect, in conjunction with any one of aspects 1 to 19, the method may further include combining a pentasilicic aluminosilicate framework with an iron precursor and a cerium precursor to form a first mixture; and calcining the first mixture to form the framework-substituted pentasilicic zeolite.

Claims

1. A method for converting hydrocarbons in a hydrocarbon stream, the method comprising contacting the hydrocarbon stream with a steam and catalyst system under steam-enhanced catalytic cracking conditions to produce an effluent containing olefins, wherein: The catalyst system comprises a framework-substituted pentasil zeolite; The framework-substituted pentasilicone zeolite has a modified pentasilicone framework, which comprises a pentasilicaluminosilicate framework, wherein a portion of the aluminum atoms in the pentasilicaluminosilicate framework are replaced by Ce and Fe atoms; and At least a portion of the Fe atoms are monomers.

2. The method of claim 1, wherein at least a portion of the Ce atoms are monomeric.

3. The method according to claim 1 or claim 2, wherein, based on the total mass of the skeleton-substituted pentasilica zeolite, the skeleton-substituted pentasilica zeolite comprises 0.2 to 1.0 wt% Ce atoms and 0.2 to 0.5 wt% Fe atoms.

4. The method according to any one of claims 1 to 3, wherein the ratio of Ce atoms to Fe atoms is 1:5 to 3:

5.

5. The method according to any one of claims 1 to 4, wherein the framework-substituted pentasilica zeolite comprises: (a) 200 m 2 / g to 600 m 2 Specific surface area per g; (b) The molar ratio of SiO2 to Al2O3 from 10 to 200; and (c) 0.1 cm 3 / g to 0.6 cm 3 / g pore volume.

6. The method according to any one of claims 1 to 5, wherein at least 80 mol% of the Ce atoms are monomeric, at least 80 mol% of the Fe atoms are monomeric, or both.

7. The method according to any one of claims 1 to 6, wherein the steam-enhanced catalytic cracking conditions comprise a steam-to-hydrocarbon ratio of 0.2 to 0.

8.

8. The method according to any one of claims 1 to 7, wherein the steam-enhanced catalytic cracking conditions include a reaction temperature of 450°C to 750°C, a reaction pressure of 1 bar to 5 bar, and a residence time of 0.5 seconds to 1000 seconds.

9. The method according to any one of claims 1 to 8, wherein the framework-substituted pentasilica zeolite is prepared by a solid-state ion exchange method, wherein solid-state ion exchange is used to replace the framework aluminum atoms with Ce and Fe atoms.

10. The method of claim 9, wherein solid-state ion exchange is used to simultaneously replace the framework aluminum atoms with Ce and Fe atoms.

11. The method according to any one of claims 1 to 10, wherein the catalyst system comprises particles with a particle size of 150 μm to 200 μm.

12. The method according to any one of claims 1 to 11, wherein the framework-substituted pentasilica zeolite is prepared by a method comprising the following steps: The pentasilyl aluminosilicate framework is combined with iron and cerium precursors to form a first mixture; and The first mixture is calcined to form the skeletal-substituted pentasilica zeolite.

13. The method according to any one of claims 1 to 11, further comprising: The pentasilicic aluminosilicate framework is combined with iron and cerium precursors to form the first mixture; and The first mixture is calcined to form the skeletal-substituted pentasilica zeolite.

14. The method according to claim 12 or claim 13, wherein the first mixture is a dry mixture.

15. The method according to any one of claims 1 to 14, wherein the effluent comprises at least 46% by weight of light olefins.

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