RU2838600C1 - Systems and methods for producing olefins - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: invention relates to a method of producing olefins, comprising: bringing a stream of hydrocarbon-containing material into contact with solid particles in a reaction vessel, wherein the solid particles react with the hydrocarbon-containing feed stream to form an olefin-containing product stream, wherein the reaction vessel is connected to a riser, wherein the reaction vessel has a maximum cross-sectional area which is at least 3 times greater than the maximum cross-sectional area of the riser, and wherein the reaction vessel performs the function of a reactor with an intense fluidized, turbulent or fluidised bed, and the riser performs the function of a riser reactor with a diluted phase. Further, passing the solid particles through the riser, wherein the riser passes through the riser opening in the outer shell of the solid particles separation section so that the riser comprises an inner riser segment located in the inner region of the solid particles separation section, and an outer segment of the riser, located outside the outer shell of the section for separating solid particles, wherein the solid particle separation section comprises at least an outer shell defining an inner region of the solid particle separation section, the outer shell comprising a gas outlet port, a riser opening and a solid particle outlet port, and wherein the outer shell comprises a gas/solid particles separation device and a solid particles collection zone in the inner area of the solid particles separation section, and wherein the riser hole is located on the side wall of the outer shell such that it is not located on the central vertical axis of the solid particles separation section; separating solid particles from the olefin-containing product stream in a gas/solid particle separation device and passing solid particles separated from the olefin-containing product stream, into solid particles collection zone located near the central vertical axis of the solid particles separation section.

EFFECT: use of the proposed invention reduces the number of side reactions and increases selectivity with respect to the end product.

14 cl, 6 dwg, 1 tbl, 2 ex

Description

Cross-references to related applications

This application claims the benefit of and priority to U.S. Patent Application Ser. No. 63/126,095, filed December 16, 2020, entitled “Systems and Methods for Producing Olefins,” the contents of which are incorporated herein by reference in their entirety.

Field of technology

Embodiments described herein relate generally to chemical processing and, more particularly, to methods and systems for catalytic chemical conversion.

Prerequisites for the creation of an invention

Lower olefins can be used as base materials for the production of many types of products and materials. For example, ethylene can be used to produce polyethylene, ethylene chloride or ethylene oxides. Such products can be used in product packaging, construction, textiles, etc. Thus, there is an industrial demand for lower olefins such as ethylene, propylene and butene. Lower olefins can be produced through a variety of chemical processes depending on the given feed stream of chemicals, which can be a product stream obtained from the refining of crude oil. Many lower olefins can be produced through processes using solid particles, such as catalysts consisting of solid particles.

The essence of the invention

Some reactor systems for processing hydrocarbon feedstocks to produce olefins include a reaction vessel located immediately below a solids separation section where a riser (connecting the reaction vessel to the separation section) extends from the reaction vessel through the bottom of the solids separation section. Such configurations can adversely affect the flow of solids through the solids separation section by creating an annular space at the bottom of the solids separation section where the outlet port cannot be centered at the bottom of the solids separation section. In addition, such configurations can result in the riser being longer than necessary, which can result in unwanted side reactions that can reduce the yield of lower olefins. In addition, such configurations can result in increased cost of process equipment since the internal riser may require high-grade materials and the bottom of the separation section may have a larger diameter to accommodate the volume occupied by the internal riser. There is a need for improved methods of producing olefins and improved system components for producing olefins.

The present document describes methods and systems for producing olefins that can solve problems identified in previous designs. In one or more embodiments, a riser does not enter a solids separation section through the bottom of the solids separation section, resulting in improved characteristics of the solids stream exiting the solids separation section. In addition, in embodiments described herein, the riser can have a shorter length compared to a riser that enters through the bottom of the solids separation section. This can result in a reduction in residence time during which side reactions can occur that reduce the yield of lower olefins.

According to one or more embodiments described herein, olefins can be produced by a method comprising contacting a hydrocarbon-containing feed stream with solid particles in a reaction vessel. Contacting the hydrocarbon-containing feed stream with the solid particles can cause the hydrocarbon-containing feed stream to react to form an olefin-containing product stream. The reaction vessel can be connected to a riser, and the reaction vessel can have a maximum cross-sectional area that is at least 3 times the maximum cross-sectional area of the riser. The method can further include passing solid particles through the riser. The riser can pass through an opening of the riser in an outer shell of the solid separation section such that the riser can comprise an inner riser segment located in an inner region of the solid separation section and an outer riser segment located outside the outer shell of the solid separation section. The solid separation section can comprise at least an outer shell defining an inner region of the solid separation section. The outer shell may comprise a gas outlet port, a riser opening, and a solids outlet port. The outer shell may comprise a gas/solids separation device and a solids collection zone in the interior of the solids separation section. The riser opening may be located on the side wall of the outer shell such that it is not located on the central vertical axis of the solids separation section. The method may further comprise separating solids from the olefin-containing product stream in the gas/solids separation device and passing the solids separated from the olefin-containing product stream into a solids collection zone located near the central vertical axis of the solids separation section.

It should be understood that both the preceding summary of the invention and the following detailed description represent embodiments of the technology and are intended to provide a general idea or concept for understanding the nature and character of the claimed technology. The accompanying drawings are provided for a more thorough understanding of the technical solutions and are incorporated into and form a part of this description. The drawings illustrate various embodiments of the invention and, together with the description, are used to explain the basic ideas and operating principles of the technical solutions. It is also intended that the drawings and description are illustrative only and are not intended to limit the scope of the claims in any way.

Additional features and advantages of the technology disclosed herein are set forth in the following detailed description and in part will be apparent to those skilled in the art from this description or learned by experience using the technology described herein, including the following detailed description, the claims, and the accompanying drawings.

Brief description of graphic materials

The following detailed description of specific embodiments of the present invention is best understood when read in conjunction with the following drawings, in which like elements are identified by like reference numerals, and where:

FIG. 1 is a schematic illustration of a reactor system comprising a reactor section and a regenerator section, in accordance with one or more embodiments described herein;

FIG. 2 is a schematic illustration of a reaction vessel and an outer riser segment in accordance with one or more embodiments described herein;

FIG. 3 is a schematic diagram of a solid particle separation section according to one or more embodiments described herein;

FIG. 4 illustrates a particulate matter collection area in accordance with one or more embodiments described herein;

FIG. 5 illustrates a particulate matter collection zone in accordance with one or more embodiments described herein; and

FIG. 6 graphically depicts residence time distributions for particulate matter collection zones in accordance with one or more embodiments described herein.

It should be understood that the drawings are schematic in nature and do not include certain components of a fluidized bed reactor system commonly used in the art, such as, but not limited to, temperature transmitters, pressure sensors, flow meters, pumps, valves, etc. It should be understood that such components do not depart from the spirit and scope of the disclosed embodiments of the invention according to this description. However, process components such as those described herein may be added to the embodiments described herein.

The following is a more detailed description of various embodiments of the present invention, some embodiments of which are shown in the accompanying drawings. Wherever possible, the same numerals are used in the drawings to indicate the same or similar parts.

Detailed description

The present document describes methods for producing olefins from hydrocarbon-containing feed streams. Such methods utilize systems that have certain features, such as a particular orientation of portions of the system. For example, in one or more embodiments described herein, the reaction vessel is not located immediately below the separation section. One particular embodiment that is described in detail herein is shown in FIG. 1. However, it should be understood that the principles described and explained herein may be applicable to other systems that utilize other system components oriented in different ways, or other reaction schemes using different catalyst compositions.

As shown in FIG. 1 and as can be understood with reference to the above figures and description, a feed chemical may react by contact with a solid particle, such as a catalyst, in the reactor section 200. The solid particles may be separated from the reaction products in the reactor section 200 and fed to a regeneration section 300. In the regeneration section 300, the solid particles may be regenerated. Such regenerated solid particles may be fed back to the reactor section 200 for subsequent reaction cycles.

Although some embodiments are described herein in the context of the reactor system 100, it should be understood that the methods and systems described herein can operate without the use of the regeneration section 300 or with alternative means for regenerating solids. Thus, it should not be understood that the regeneration section 300 is necessary or essential for all embodiments of the methods and systems described herein.

In non-limiting examples, the reactor system 100 described herein can be used to produce lower olefins from hydrocarbon feedstock streams. Lower olefins can be produced from a variety of hydrocarbon feedstock streams through a variety of reaction mechanisms. For example, lower olefins can be produced through at least one of dehydrogenation processes, cracking processes, dehydration processes, and methanol-to-olefin conversion processes. These types of reactions can use a variety of feedstock streams and a variety of solid particles to produce lower olefins. It should be understood that references herein to "catalysts" can equally include the solid particles referenced in connection with the system of FIG. 1.

According to one or more embodiments of the invention, the chemical reaction may be a dehydrogenation chemical reaction. According to such embodiments, the hydrocarbon-containing feed stream may comprise one or more of ethylbenzene, ethane, propane, n-butane, and isobutane. According to one or more embodiments, the hydrocarbon-containing feed stream may comprise at least 50 wt.%, at least 60 wt.%, at least 70 wt.%, at least 80 wt.%, at least 90 wt.%, at least 95 wt.%, or even at least 99 wt.% of ethylbenzene. According to one or more embodiments, the hydrocarbon-containing feed stream may comprise at least 50 wt.%, at least 60 wt.%, at least 70 wt.%, at least 80 wt.%, at least 90 wt.%, at least 95 wt.%, or even at least 99 wt.% of ethane. In further embodiments, the hydrocarbon-containing feed stream may comprise at least 50 wt.%, at least 60 wt.%, at least 70 wt.%, at least 80 wt.%, at least 90 wt.%, at least 95 wt.%, or even at least 99 wt.% of propane. In further embodiments, the hydrocarbon-containing feed stream may comprise at least 50 wt.%, at least 60 wt.%, at least 70 wt.%, at least 80 wt.%, at least 90 wt.%, at least 95 wt.%, or even at least 99 wt.% of n-butane. In further embodiments, the hydrocarbon-containing feed stream may comprise at least 50 wt.%, at least 60 wt.%, at least 70 wt.%, at least 80 wt.%, at least 90 wt.%, at least 95 wt.%, or even at least 99 wt.% of isobutane. In further embodiments, the hydrocarbon-containing feed stream may comprise at least 50 wt.%, at least 60 wt.%, at least 70 wt.%, at least 80 wt.%, at least 90 wt.%, at least 95 wt.%, or even at least 99 wt.% of the total amount of ethane, propane, n-butane, and isobutane.

In one or more embodiments, solid particles of gallium and/or platinum can be used as a catalyst in the dehydrogenation reaction. In such embodiments, the solid particles can comprise a gallium and/or platinum catalyst. According to the present description, the gallium and/or platinum catalyst comprises gallium, platinum, or both. The gallium and/or platinum catalyst can be formed on an alumina support or an aluminosilicate support and can optionally comprise potassium. Such gallium and/or platinum catalysts are disclosed in U.S. Patent No. 8,669,406, the contents of which are incorporated herein by reference in their entirety. At the same time, it should be understood that other suitable catalysts can be used to carry out the chemical dehydrogenation reaction.

In one or more embodiments, the reaction mechanism may be dehydrogenation followed by combustion (in the same chamber). In such embodiments, the dehydrogenation reaction may produce hydrogen as a byproduct, and the oxygen carrier material may contact the hydrogen and facilitate the combustion of hydrogen to form water. Examples of such reaction mechanisms, which are considered as possible reaction mechanisms for the systems and methods described herein, are described in WO 2020/046978, the teachings of which are incorporated herein by reference in their entirety.

According to one or more embodiments of the invention, the chemical process may be a cracking process. According to such embodiments, the hydrocarbon-containing feed stream may comprise one or more of naphtha, n-butane, or isobutane. According to one or more embodiments, the hydrocarbon-containing feed stream may comprise at least 50 wt.%, at least 60 wt.%, at least 70 wt.%, at least 80 wt.%, at least 90 wt.%, at least 95 wt.%, or even at least 99 wt.% naphtha. In further embodiments, the hydrocarbon-containing feed stream may comprise at least 50 wt.%, at least 60 wt.%, at least 70 wt.%, at least 80 wt.%, at least 90 wt.%, at least 95 wt.%, or even at least 99 wt.% n-butane. In further embodiments, the hydrocarbon-containing feed stream may comprise at least 50 wt.%, at least 60 wt.%, at least 70 wt.%, at least 80 wt.%, at least 90 wt.%, at least 95 wt.%, or even at least 99 wt.% of isobutane. In further embodiments, the hydrocarbon-containing feed stream may comprise at least 50 wt.%, at least 60 wt.%, at least 70 wt.%, at least 80 wt.%, at least 90 wt.%, at least 95 wt.%, or even at least 99 wt.% of the total amount of naphtha, n-butane, and isobutane.

In one or more embodiments, one or more zeolites may be used as a catalyst in the cracking reaction. In such embodiments, the solid particles may comprise one or more zeolites. In some embodiments, the one or more zeolites used in the cracking reaction may comprise a ZSM-5 zeolite. However, it should be understood that other suitable catalysts may be used to perform the cracking reaction. For example, suitable commercially available catalysts may include Intercat Super Z Excel or Intercat Super Z Exceed. In further embodiments, the cracking catalyst may comprise platinum in addition to the catalytically active material. For example, the cracking catalyst may comprise from 0.001 wt.% to 0.05 wt.% platinum. The platinum may be sputtered as platinum nitrate and calcined at an elevated temperature, such as about 700 °C. Without being limited by theory, it is believed that adding platinum to the catalyst could facilitate the combustion of auxiliary fuels such as methane.

According to one or more embodiments of the invention, the chemical process may be a dehydration process. According to such embodiments, the hydrocarbon-containing feed stream may comprise one or more of ethanol, propanol, or butanol. According to one or more embodiments, the hydrocarbon-containing feed stream may comprise at least 50 wt.%, at least 60 wt.%, at least 70 wt.%, at least 80 wt.%, at least 90 wt.%, at least 95 wt.%, or even at least 99 wt.% ethanol. In further embodiments, the hydrocarbon-containing feed stream may comprise at least 50 wt.%, at least 60 wt.%, at least 70 wt.%, at least 80 wt.%, at least 90 wt.%, at least 95 wt.%, or even at least 99 wt.% propanol. In further embodiments, the hydrocarbon-containing feed stream may comprise at least 50 wt.%, at least 60 wt.%, at least 70 wt.%, at least 80 wt.%, at least 90 wt.%, at least 95 wt.%, or even at least 99 wt.% butanol. In further embodiments, the hydrocarbon-containing feed stream may comprise at least 50 wt.%, at least 60 wt.%, at least 70 wt.%, at least 80 wt.%, at least 90 wt.%, at least 95 wt.%, or even at least 99 wt.% of the total amount of ethanol, propanol, and butanol.

In one or more embodiments, one or more acid catalysts may be used in the dehydration reaction. In such embodiments, the solid particles may comprise one or more acid catalysts. In some embodiments, the one or more acid catalysts used in the dehydration process may comprise a zeolite (e.g., ZSM-5 zeolite), alumina, amorphous aluminosilicate, acidic clay, or a combination of the foregoing. For example, in accordance with one or more embodiments, commercially available alumina catalysts that may be suitable include SynDol (available from Scientific Design Company), V200 (available from UOP), or P200 (available from Sasol). Commercially available zeolite catalysts that may be suitable include CBV 8014, CBV 28014 (both available from Zeolyst). Commercially available amorphous aluminosilicate catalysts that may be suitable include grade 135 aluminosilicate catalyst supports (available from Sigma Aldrich). However, it should be understood that other suitable catalysts may be used to perform the dehydration process.

According to one or more embodiments of the invention, the chemical process may be a process for converting methanol to an olefin. According to such embodiments, the hydrocarbon-containing feed stream may comprise methanol. According to one or more embodiments, the hydrocarbon-containing feed stream may comprise at least 50 wt.%, at least 60 wt.%, at least 70 wt.%, at least 80 wt.%, at least 90 wt.%, at least 95 wt.%, or even at least 99 wt.% methanol.

In one or more embodiments of the invention, one or more zeolites may be used as a catalyst in the methanol to olefin conversion reaction. In such embodiments, the solid particles may comprise one or more zeolites. In some embodiments, one or more zeolites used in the methanol to olefin conversion process may comprise one or more of a ZSM-5 zeolite or a SAPO-34 zeolite. At the same time, it should be understood that other suitable catalysts may be used to perform the methanol to olefin conversion process.

In one or more embodiments, controlling the chemical process may include releasing a product stream from the reactor. The product stream may comprise lower olefins or alkylated aromatic olefins, such as styrene. As described herein, "light olefins" refer to one or more of ethylene, propylene, or butene. As described herein, butene may include any isomer of butene, such as α-butylene, cis-β-butylene, trans-β-butylene, and isobutylene. In an embodiment, the product stream may comprise at least 50 wt.% light olefins. For example, the product stream may contain at least 60 wt.% light olefins, at least 70 wt.% light olefins, at least 80 wt.% light olefins, at least 90 wt.% light olefins, at least 95 wt.% light olefins, or even at least 99 wt.% light olefins.

Referring to FIG. 1, the reactor system 100 generally comprises a plurality of system components, such as a reactor section 200 and a regeneration section 300. As used herein in the context of FIG. 1, the reactor section 200 generally refers to a portion of the reactor system 100 in which the primary process reaction occurs and solid particles are separated from the olefin-containing reaction product stream. In one or more embodiments, the solid particles may be spent, which means that they are at least partially deactivated. Also as used herein, the term "regeneration section 300" generally refers to a portion of the fluidized bed reactor system in which solid particles are regenerated, such as by combustion, and the regenerated solid particles are separated from other process materials, such as off-gases from material previously burned on the spent solid particles or from additional fuel. The reactor section 200 essentially includes a reaction vessel 250, a riser 230 including an outer riser segment 232 and an inner riser segment 234, and a solids separation section 210. The regeneration section 300 essentially includes a solids treatment vessel 350, a riser 330 including an outer riser segment 332 and an inner riser segment 334, and a solids separation section 310. Essentially, the solids separation section 210 can be in fluid communication with the solids treatment vessel 350, for example, through the penetration 126, and the solids separation section 310 can be in fluid communication with the reaction vessel 250, for example, through the penetration 124 and the transport riser 130.

In essence, the reactor system 100 can be operated by feeding a hydrocarbon-containing feedstock and fluidized solids into a reaction vessel 250 and performing a reaction by contacting the hydrocarbon-containing feedstock with the fluidized solids to produce an olefin-containing product in the reaction vessel 250 of the reactor section 200. The olefin-containing product and solids can be passed from the reaction vessel 250 and through the riser 230 into the gas/solids separation device 220 in the solids separation section 210, where the solids can be separated from the olefin-containing product. The solids can then be transported from the solids separation section 210 to the solids treatment vessel 350. In the solids treatment vessel 350, the solids can be regenerated through chemical processes. For example, the spent solids may be regenerated by one or more of oxidizing the solids by contact with an oxygen-containing gas, burning coke present on the solids, and burning additional fuel to heat the solids. The solids may then be passed from the solids treatment vessel 350 and through the riser 330 to the riser terminal device 378, where a partial separation of the gas and solids from the riser 330 occurs. The gas and the remaining solids from the riser 330 are transported to the gas/solids separation device 320 in the solids separation section 310, where the remaining solids are separated from the gases from the regeneration reaction. The solids separated from the gases may be transferred to the solids collection zone 380. The separated solids are then transferred from the solids collection zone 380 to the reaction vessel 250 for further use. In this way, solid particles can circulate between the reactor section 200 and the regeneration section 300.

In one or more embodiments, the reactor system 100 may include either a reactor section 200 or a regeneration section 300, but not both. In further embodiments, the reactor system 100 may include one regeneration section 300 and a plurality of reactor sections 200.

In addition, as described herein, the structural features of the reactor section 200 and the regeneration section 300 may be similar or identical in some respects. For example, each of the reactor section 200 and the regeneration section 300 includes a reaction vessel (i.e., a reaction vessel 250 of the reactor section 200 and a solids treatment vessel 350 of the regeneration section 300), a riser (i.e., a riser 230 of the reactor section 200 and a riser 330 of the regeneration section 300), and a solids separation section (i.e., a solids separation section 210 of the reactor section 200 and a solids separation section 310 of the regeneration section 300). It should be understood that since many of the structural features of the reactor section 200 and the regeneration section 300 may be similar or identical in some respects, in the present description similar or identical portions of the reactor section 200 and the regeneration section 300 have been designated by reference numerals with the same last two digits, and disclosures relating to one portion of the reactor section 200 may be applicable to a similar or identical portion of the regeneration section 300, and vice versa.

As shown in FIGS. 1 and 2, the reaction vessel 250 may include a reaction vessel solids inlet port 252 that forms a connection between the transport riser 130 and the reaction vessel 250. The reaction vessel 250 may further include a reaction vessel outlet port 254 that is in fluid communication with or directly connected to the outer segment 232 of the riser 230. As used herein, the term "reaction vessel" means a drum, cylinder, vat, or other container suitable for a given chemical reaction. The reaction vessel may be substantially cylindrical in shape (i.e., having a substantially circular diameter) or may alternatively be non-cylindrical in shape, such as a prism formed with a cross-sectional shape of triangles, rectangles, pentagons, hexagons, octagons, ovals, or other polygons, or curved closed shapes, or combinations thereof. The reaction vessels used in the present disclosure may substantially include a metal frame and may further include refractory linings or other materials used to protect the metal frame and/or control process conditions.

In general, the "inlets" and "outlets" of any system unit of the fluidized catalyst reactor system 100 described herein refer to openings, through-holes, channels, slots, gaps or other similar mechanical elements in the system unit. For example, inlets provide a means for materials to be fed into a particular system unit, and outlets provide a means for materials to be discharged from a particular system unit. In general, an outlet or inlet will form a region of the system unit of the fluidized catalyst reactor system 100 to which a pipe, conduit, tube, hose, transport line or similar mechanical element is attached, or to a portion of the system unit to which another system unit is directly attached. Although inlets and outlets may sometimes be described herein in functional action, they may have similar or identical physical characteristics, and their respective functions in the working system should not be construed as limiting their physical designs. Other openings, such as riser opening 218, may comprise an opening in a given system unit at a location where other system units are directly connected, such as where riser 230 extends into solids separation section 210 at riser opening 218.

The reaction vessel 250 can be connected to a riser 130, which, during operation, can feed regenerated solids and chemicals into the reactor section 200. As shown in FIG. 2, the regenerated solids and chemical feedstock can be mixed by means of a distributor 260 located in the reaction vessel 250. As shown in FIG. 1, the solids entering the reaction vessel 250 through the riser 130 can pass through the passage 124 to the riser 130, thus coming from the regeneration section 300. In some embodiments, the solid particles may pass directly from the solid particle separation section 210 through the passage 122 and into the transport riser 130, through which they pass into the reaction vessel 250. These solid particles may be partially deactivated, but in some embodiments they may still be acceptable for use in the reaction vessel 250.

As shown in FIGS. 1 and 2, the reaction vessel 250 can be directly connected to the outer segment 232 of the riser. In one embodiment, the reaction vessel 250 can include a section 256 of the reaction vessel body and a transition section 258 of the reaction vessel located between the section 256 of the reaction vessel body and the outer segment 232 of the riser. The section 256 of the reaction vessel body can substantially have a larger diameter than the transition section 258 of the reaction vessel, and the transition section 258 of the reaction vessel can be narrowed from the size of the diameter of the section 256 of the reaction vessel body to the size of the diameter of the riser 230 such that the transition section 258 of the reaction vessel projects inwardly from the section 256 of the reaction vessel body to the outer segment 232 of the riser. It should be understood that in this document, the diameter of a part of a system node denotes its overall width, as shown in the horizontal direction in FIG. 1.

In addition, the section 256 of the reaction vessel body may substantially have a height, where the height of the section 256 of the reaction vessel body is measured from the inlet port 152 for solid particles to the transition section 258 of the reaction vessel. In one or more embodiments, the diameter of the section 256 of the reaction vessel body may be greater than the height of the section 256 of the reaction vessel body. In one or more embodiments, the diameter to height ratio of section 256 of the reaction vessel body may be from 5:1 to 1:5. For example, the diameter to height ratio of section 356 of the solids processing vessel body may be from 5:1 to 1:5, from 4:1 to 1:5, from 3:1 to 1:5, from 2:1 to 1:5, from 1:1 to 1:5, from 1:2 to 1:5, from 1:3 to 1:5, from 1:4 to 1:5, from 5:1 to 1:4, from 5:1 to 1:3, from 5:1 to 1:2, from 5:1 to 1:1, from 5 :1 to 2:1, 5:1 to 3:1, 5:1 to 4:1, or any combination or subcombination of these ranges.

In one or more embodiments, the reaction vessel 250 may have a maximum cross-sectional area that is at least 3 times the maximum cross-sectional area of the riser 230. For example, the reaction vessel 250 may have a maximum cross-sectional area that is at least 3, at least 4, at least 5, at least 6, at least 7, at least 8, at least 9, or even at least 10 times the maximum cross-sectional area of the riser 230. In accordance with the present description, unless explicitly stated otherwise, the term "cross-sectional area" means the cross-sectional area of a portion of a component of the system lying in a plane substantially perpendicular to the direction of the general flow of reactants and/or products.

In one or more embodiments, depending on the shape, size, and other process conditions such as the temperature and pressure in the reaction vessel 250 and the riser 230, the reaction vessel 250 can operate in a mode that is isothermal or near isothermal, such as in a reactor with an intense fluidized, turbulent, or ebullated bed, while the riser 230 can operate to a greater extent in a plug flow mode, such as in a dilute phase riser reactor. For example, the reaction vessel 250 can function as a reactor with an intense fluidized, turbulent, or ebullated bed and the riser 230 can function as a dilute phase riser reactor, whereby an average flow of catalyst and gas moves upward together. As used herein, the term "average flow" means the total upward flow minus the reverse flow, which is generally typical of the behavior of fluidized particles. As described herein, the term "intense fluidization reactor" may refer to a reactor with a fluidization regime in which the superficial velocity of the gas phase is higher than the choke velocity and which may be partially dense during operation. As described herein, a "turbulent bed" reactor may refer to a fluidization regime in which the linear velocity is less than the choke velocity, wherein said bed is denser than a fast fluidization regime. As described herein, the term "fluidized bed reactor" may refer to a fluidization regime in which clearly defined bubbles are present in two different phases in a high-density bed. "Choke velocity" refers to the minimum velocity required to maintain solids in a dilute phase regime in a vertical movement line. As described herein, a “dilute phase lift reactor” may refer to a lift reactor operating at a transfer rate at which the gas and catalyst have approximately the same velocity in the dilute phase.

In one or more embodiments, the pressure in the reaction vessel 250 may be in a range of from 6.0 to 100 pounds per square inch absolute (psia) (from about 41.4 kilopascals (kPa) to about 689.4 kPa), but in some embodiments, a narrower specified range may be used, such as from 15.0 psia to 35.0 psia (from about 103.4 kPa to about 241.3 kPa). For example, the pressure may be from 15.0 psia to 30.0 psia (from about 103.4 kPa to about 206.8 kPa), from 17.0 psia to 28.0 psia (from about 117.2 kPa to about 193.1 kPa), or from 19.0 psia to 25.0 psia (from about 131.0 kPa to about 172.4 kPa). Conversions of units from standard (non-SI) to metric (SI) expressions in this document include the term "about" to indicate rounding that may be present in metric (SI) expressions as a result of the conversions.

In additional embodiments, the weight hourly space velocity (WHSV) for the disclosed process can range from 0.1 pounds (lb) to 100 pounds of chemical feedstock per hour (hr) per pound of catalyst in the reactor (lb feedstock/hr/lb catalyst). For example, when the reactor comprises a reaction vessel 250 that functions as a reactor with an intense fluidized, turbulent, or ebullated bed and a riser 230 that functions as a riser reactor, the superficial gas velocity can be from 2 feet per second (ft/s, about 0.61 meters per second, m/s) to 80 ft/s (about 24.38 m/s), such as from 2 ft/s (about 0.61 m/s) to 10 ft/s (about 3.05 m/s) in the reaction vessel 250 and from 30 ft/s (about 9.14 m/s) to 70 ft/s (about 21.31 m/s) in the riser 230. In additional embodiments, a reactor configuration that fully corresponds to the type the riser reactor may operate at a single high linear gas velocity, such as, in some embodiments, at least 30 ft/s (about 9.15 m/s) throughout.

In further embodiments, the ratio of catalyst to feed stream in reaction vessel 250 and riser 230 may be in the range of 5 to 100 on a weight basis (w/w). In some embodiments, said ratio may be in the range of 10 to 40, such as 12 to 36 or 12 to 24.

In additional embodiments, the catalyst flow can be from 1 pound per square foot per second (lb/ft ² -s) (about 4.89 kg/m ² -s) to 30 lb/ft ² -s (about 146.5 kg/m ² -s) in reaction vessel 250 and from 10 lb/ft ² -s (about 48.9 kg/m ² -s) to 250 lb/ft ² -s (about 1221 kg/m ² -s) in riser 230.

FIG. 1 also shows a reactor section 200 that may include a riser 230 that serves to transfer reactants, products, and/or solids from the reaction vessel 250 to the solids separation section 210. In one or more embodiments, the riser 230 may be substantially cylindrical in shape (i.e., having a substantially circular cross-sectional shape) or may alternatively be non-cylindrical in shape, such as a prism formed with a cross-sectional shape of triangles, rectangles, pentagons, hexagons, octagons, ovals, or other polygons, or curved closed shapes, or combinations thereof. The riser 230 used in the present description may substantially include a metal frame and may further include refractory linings or other materials used to protect the metal frame and/or control process conditions.

According to some embodiments, the riser 230 may include an outer riser segment 232 and an inner riser segment 234. As used herein, the term "outer riser segment" refers to the portion of the riser that is located outside the solids separation section, and the term "inner riser segment" refers to the portion of the riser that is located inside the solids separation section. For example, in the embodiment shown in FIG. 1, the inner riser segment 234 of the reactor section 200 may be located inside the solids separation section 210, while the outer riser segment 232 is located outside the solids separation section 210.

As shown in FIG. 1 and 3, the solid particle separation section 210 may comprise an outer shell 212, where the outer shell 212 may form an inner region 214 of the solid particle separation section 210. The outer shell 212 may comprise a gas outlet port 216, a riser opening 218, and a solid particle outlet port 222. In addition, the outer shell 212 may comprise a gas/solid particle separation device 220 and a solid particle collection zone 280 in the inner region 214 of the solid particle separation section 210.

In one or more embodiments, the outer shell 212 of the solid particle separation section 210 may form an upper segment 276, a middle segment 274, and a lower segment 272 of the solid particle separation section 210. Substantially, the upper segment 276 may have a substantially constant cross-sectional area, such that the cross-sectional area does not vary by more than 20% across the upper segment 276. In one or more embodiments, the cross-sectional area of the upper segment 276 may be at least three times the maximum cross-sectional area of the riser 230. For example, the cross-sectional area of the upper segment 276 may be at least 3 times, at least 4 times, at least 5 times, at least 6 times, at least 7 times, at least 8 times, at least 9 times, at least 10 times, at least 12 times, at least 15 times, or even at least 20 times the maximum cross-sectional area of the riser 230. In other embodiments, the maximum cross-sectional area of the upper segment 276 may be 5 to 40 times the maximum cross-sectional area of the riser 230. For example, the maximum cross-sectional area of the upper segment 276 may be 5–40, 10–40, 15–40, 20–40, 25–40, 30–40, 35–40, 5–35, 5–30, 5–25, 5–20, 5–15 or even 5–10 times the maximum cross-sectional area of the riser 230.

In addition, in one or more embodiments, the lower segment 272 of the solid particle separation section 210 may have a substantially constant cross-sectional area, such that the cross-sectional area does not change by more than 20% in the lower segment 272. The cross-sectional area of the lower segment 272 may be greater than the maximum cross-sectional area of the riser 230 and less than the maximum cross-sectional area of the upper segment 276. The middle segment 274 may have the shape of a truncated cone, in which the cross-sectional area of the middle segment 274 is not constant and the cross-sectional area of the middle segment 274 transitions from the cross-sectional area of the upper segment 276 to the cross-sectional area of the lower segment 272 along the middle segment 274.

As shown in FIG. 3, the solids separation section 210 may comprise a central vertical axis 299. The central vertical axis may pass through an upper portion of the solids separation section 210 and a lower portion of the solids separation section 210, such that the central vertical axis 299 passes through an upper segment 276, a middle segment 274, and a lower segment 272 of the solids separation section 210. In one or more embodiments, the upper segment 276, the middle segment 274, and the lower segment 272 of the solids separation section 210 may be centered on the central vertical axis 299. For example, in embodiments in which the upper segment 276 and the lower segment 272 are substantially cylindrical, the central vertical axis 299 may pass through the midpoint of the diameter of the upper segment 276 and the midpoint of the diameter of the lower segment 272.

As shown in FIGS. 1 and 3, the inner segment 234 of the riser 230 can pass through the riser opening 218 of the solids separation section 210. The riser opening 218 can be any opening in the outer shell 212 of the solids separation section 210 through which at least the inner segment 234 of the riser 230 projects into the inner region 214 of the solids separation section 210. In one or more embodiments, the riser opening 218 is not located on the central vertical axis 299 of the solids separation section 210. In such embodiments, the riser opening 218 can be located on the side wall of the outer shell 212 such that the riser opening 218 is not located on the central vertical axis 299 and is not oriented such that the riser 230 extends into the solids separation section 210 in a direction substantially parallel to the central vertical axis 299.

In one or more embodiments, the inner riser segment 234 enters the solids separation section 210 at the middle segment 274 of the solids separation section 210. In such embodiments, the inner riser segment 234 passes through at least a portion of the middle segment 274 and through at least a portion of the upper segment 276. In such embodiments, the inner riser segment 234 does not pass through the lower segment 272 of the solids separation section 210. In other embodiments, the inner riser segment 234 can enter the solids separation section 210 at the upper segment 276 and the inner riser segment 234 can pass through at least a portion of the upper segment 276. In such embodiments, the inner riser segment 234 does not pass through the lower segment 272 or the middle segment 274.

As shown in FIG. 3, the inner riser segment 234 may comprise a vertical portion 296, a non-vertical portion 294, and a non-straight portion 295. As described herein, the term "non-straight portion" may refer to a portion or segment of a riser that comprises a curve or a beveled joint. The non-straight portion 295 may be located between the vertical portion 296 and the non-vertical portion 294 and may connect the vertical portion 296 and the non-vertical portion 294. In addition, the non-vertical portion 294 of the inner riser segment 234 may be near the riser opening 218. In one or more embodiments, the non-vertical portion 294 of the inner riser segment 234 may be adjacent to or directly connected to the riser opening 218. Thus, the riser 230 can pass through the riser opening 218 in a non-vertical direction.

As shown in FIG. 2, the outer riser segment 232 may comprise a vertical portion 291, a non-vertical portion 293, and a non-rectilinear portion 292. The non-rectilinear portion 292 may be located between the vertical portion 291 and the non-vertical portion 293 and may connect the vertical portion 291 and the non-vertical portion 293. The non-vertical portion 293 of the outer riser segment 232 may be located near the riser opening 218. In one or more embodiments, the non-vertical portion 293 of the outer riser segment 232 may be adjacent to or directly connected to the riser opening 218. In addition, the vertical section 291 of the outer segment 232 of the riser may be located near the reaction vessel 250. In such embodiments, the temperature compensation joint 282, described in more detail herein, may be located between the vertical section 291 of the outer segment 232 of the riser and the reaction vessel 250.

In one or more embodiments, riser 230 may extend through riser opening 218 in a diagonal direction, wherein the diagonal direction is from 15 to 75 degrees from vertical. For example, the diagonal direction can be from 15 to 75 degrees from vertical, from 20 to 75 degrees from vertical, from 25 to 75 degrees from vertical, from 30 to 75 degrees from vertical, from 35 to 75 degrees from vertical, from 40 to 75 degrees from vertical, from 45 to 75 degrees from vertical, from 50 to 75 degrees from vertical, from 55 to 75 degrees from vertical, from 60 to 75 degrees from vertical, from 65 to 75 degrees from vertical, from 70 to 75 degrees from vertical, from 15 to 70 degrees from vertical, from 15 to 65 degrees from vertical, from 15 to 60 degrees from vertical, from 15 to 55 degrees from vertical, from 15 to 50 degrees from vertical, from 15 to 45 degrees from vertical, from 15 to 40 degrees from vertical, from 15 to 35 degrees from vertical, from 15 to 30 degrees from vertical, from 15 to 25 degrees from vertical, from 15 to 20 degrees from vertical, or any combination or subcombination of these ranges. In one or more alternative embodiments, the riser 230 can extend through the riser opening 218 is a substantially horizontal direction. As described in this document, a “substantially horizontal” direction may be within 15 degrees of horizontal, within 10 degrees of horizontal, or even within 5 degrees of horizontal.

Without being limited by any theory, it is believed that when the riser opening 218 is not located on the central vertical axis 299 and the riser 230 enters the solids separation section 210 non-vertically, the reaction vessel 250 can be located closer to the gas/solids separation device 220. In this way, the gases and solids travel a shorter distance in the riser 230, which reduces the possibility of side reactions occurring within the riser 230. Such side reactions can be undesirable since they can lead to a decrease in the yield of lower olefins.

As shown in FIG. 3, in the upper segment 276 of the solid particle separation section 210, the inner riser segment 234 may be in fluid communication with the gas/solid particle separation device 220. For example, the vertical portion 296 of the inner riser segment 234 may be directly connected to the gas/solid particle separation device 220. The gas/solid particle separation device 220 may be any mechanical or chemical separation device that can separate solid particles from the gas or liquid phases, such as a cyclone or a plurality of cyclones.

According to one or more embodiments, the gas/solid separation device 220 may be a cyclonic separation system that may include two or more cyclonic separation stages. In embodiments where the gas/solid separation device 220 includes more than one cyclonic separation stage, the first separation device that receives the fluidized stream is referred to as a primary cyclonic separation device. The fluidized stream from the primary cyclonic separation device may be fed to a secondary cyclonic separation device for further separation. Primary cyclonic separation devices may include, for example, the primary cyclones and systems commercially available under the names VSS (commercially available from UOP), LD2 (commercially available from Stone and Webster), and RS2 (commercially available from Stone and Webster). Primary cyclones are described in, for example, U.S. Pat. Nos. 4,579,716; 5,190,650; and 5,275,641, the entire contents of each of which are incorporated herein by reference. In some separation systems that employ primary cyclones as the primary cyclonic separation device, one or more sets of additional cyclones, such as secondary cyclones and tertiary cyclones, are used to further separate the solids from the gaseous product. It should be understood that any primary cyclonic separation device can be used in the embodiments presented herein.

The solid particles may move upward through the riser 230 from the reaction vessel 250 and into the gas/solid particle separation device 220. The gas/solid particle separation device 220 may be used to deposit the separated solid particles into the lower portion of the upper segment 276 or into the middle segment 274 or into the lower segment 272 of the solid particle separation section 210. The separated vapors may be removed from the fluidized catalyst reactor system 100 through the pipe 120 at the gas outlet port 216 of the solid particle separation section 210.

As shown in FIGS. 1 and 3, the lower segment 272 of the solid particle separation section 210 may comprise a solid particle collection zone 280. In one or more embodiments, the solid particle collection zone 280 may allow solid particles to accumulate within the solid particle separation section 210. The solid particle collection zone 280 may comprise a stripping section. The stripping section may be used to remove product vapors from the solid particles before they are sent to the recovery section 300. Since the product vapors sent to the recovery section 300 are subject to combustion, it is desirable to remove these product vapors using a stripping device that uses less expensive gases than the product gases.

The solid particle collection zone 280 in the lower segment 272 may comprise a solid particle outlet port 222. In one or more embodiments, the solid particle outlet port 222 may be located near or even on the central vertical axis 299. According to one or more embodiments, the lower portion of the solid particle collection zone 280 may be curved such that the solid particle outlet port 222 is located at the lowest portion of the solid particle collection zone 280. The passage 126 may be connected to the solid particle separation section 210 at the location of the solid particle outlet port 222, and the solid particles may be transferred from the reactor section 200 through the passage 126 and into the regeneration section 300. Optionally, the solid particles may also be transferred directly back to the reaction vessel 250 through the passage 122. In such embodiments, each of the passage 122 and the passage 126 may be offset relative to the central vertical axis 229. Alternatively, the solid particles may be pre-mixed with the regenerated solid particles in the transfer riser 130.

Without being bound by any theory, it is believed that when the riser 230 does not pass through the solids collection zone 280 and when the solids outlet port 222 is located on the central vertical axis 299, the flow of solids through the solids collection zone 280 can be improved compared to configurations in which the riser 230 passes through the solids collection zone 280. If the riser 230 does not pass through the solids collection zone 280 and the riser opening 218 is not located on the central vertical axis 299, then the solids outlet port 222 can be located on the central vertical axis 299. In this way, the solids can move through the solids collection zone 280 in a manner that more closely resembles plug flow. This can result in an increase in the residence time of the solids in the solids collection zone 280, which can provide advantages in stripping or other contemplated processes occurring within the solids collection zone 280.

As described herein, portions of system assemblies, such as reactor vessel walls, separator section walls, or riser walls, may comprise a metallic material, such as carbon or stainless steel. In addition, the walls of various system assemblies may have portions attached to other portions of the same system assemblies or to another system assemblies. Sometimes in this document, attachment or connection points are referred to as "attachment points" and may include any known bonding agent, such as, but not limited to, a weld, adhesive, solder, etc. It should be understood that system components may be "directly joined" at an attachment point, such as a weld.

In order to reduce damage caused by hot solid particles and gases, refractory materials can be used as an internal lining of various components of the system. Refractory materials can be included in the riser 230, as well as in the solid particle separation section 210. It should be understood that although embodiments are made of specific configurations of refractory materials and materials, they should not be considered as limiting the physical structure of the disclosed system. For example, the refractory lining can extend in the riser 230 along the inner surface of the riser 230 and along the inner surfaces of the middle segment 274 and the upper segment 276 of the solid particle separation section 210. The refractory lining can include a hexagonal mesh or other suitable refractory materials.

The mechanical loads applied to the reaction vessel 250 and, in particular, to the connected nozzles, such as 218, of the vessel from the solids side and other parts of the reactor section 200, can be high, and springs can be used to provide movement of the vessel due to differences in temperature of the vessel walls and piping. These springs can apply an upward pressure on the reaction vessel 250 and the nozzle 218 when the vessel is empty. When the vessel has a set mass of catalyst, the loads on the nozzle 218 can shift downward. Such a design allows to reduce the overall load on the nozzle 218 in all directions. For example, the reaction vessel 250 can be suspended by springs or springs can be located under the reaction vessel 250 to support its mass, the mass of the catalyst and to provide thermal movements. For example, in FIG. 1 shows spring supports 188 mechanically attached to reactor section 200 on reaction vessel 250, wherein reactor section 200 is suspended on the supporting structure by means of spring supports 188.

In addition, the reaction vessel 250 and the riser 230 can be subject to thermal expansion. Thus, suspending the reaction vessel 250 with the spring supports 188 or supporting the reaction vessel 250 with the spring supports 188 can relieve the tension between the reaction vessel 250 and the outer segment 232 of the riser. As shown in FIG. 2, instead of springs, a thermal expansion joint 282 can be located between the reaction vessel 250 and the outer segment 232 of the riser. As described herein, the term "thermal expansion joint" can refer to seams made of metal or another suitable material, such as a fireproof, plastic, fiber or elastomer, which reduces the stress between the components of the system connected by the thermal expansion joint. For example, expansion joints can be used to reduce the stress between the components of the system due to thermal expansion and contraction. In one or more embodiments, the thermal expansion joint 282 may be used in combination with spring supports to reduce stress caused by thermal expansion between the reaction vessel 250 and the outer riser segment 232.

After separation in the solid particle separation section 210, the spent solid particles are transferred to the regeneration section 300. The regeneration section 300, as described herein, may have many structural similarities with the reactor section 200. Thus, the reference numerals assigned to parts of the regeneration section 300 are similar to the reference numerals used with respect to the reactor section 200, and if the last two digits of the reference numeral are the same, these parts of the reactor section 200 and the regeneration section 300 may perform similar functions and have a similar physical structure. Thus, many of the present disclosures related to the reactor section 200 may be equally applied to the regeneration section 300, and the differences between the reactor section 200 and the regeneration section 300 will be disclosed below in the present description.

With reference to the regeneration section 300, such as shown in FIG. 1, the solids treatment vessel 350 of the regeneration section 300 may include one or more reactor vessel inlet ports 352 and a reactor vessel outlet port 354 that is in fluid communication with or directly connected to the outer segment 332 of the riser 330. The solids treatment vessel 350 may be in fluid communication with the solids separation section 210 via a penetration 126 that may feed spent solids from the reactor section 200 to the regeneration section 300 for regeneration. The solids treatment vessel 350 may include an additional reactor vessel inlet port 352, wherein the gas inlet 128 is connected to the solids treatment vessel 350. Through the gas inlet 128, reaction gases such as additional gaseous fuel and oxygen-containing gases, including air, can be supplied, which can be used for at least partial regeneration of solid particles. In one or more embodiments, the solid particle processing vessel 350 can comprise a plurality of additional reactor vessel inlet ports, and each additional reactor vessel inlet port can supply a separate reaction fluid to the solid particle processing vessel 350. For example, the solid particles can be coked after reactions in the reaction vessel 250, and the coke can be removed from the solid particles by means of a combustion reaction. For example, oxygen-containing gases such as air can be supplied to the solid particle processing vessel 350 through the gas inlet 128 for oxidation of the solid particles, or additional fuel can be supplied to the solid particle processing vessel 350 and burned to heat the solid particles.

As shown in FIG. 1, the solids processing vessel 350 can be directly connected to the outer segment 332 of the riser 330. In one embodiment, the solids processing vessel 350 can include a solids processing vessel body section 356 and a solids processing vessel transition section 358. The solids processing vessel body section 356 can substantially have a larger diameter than the solids processing vessel transition section 358, and the solids processing vessel transition section 358 can be tapered from the diameter of the solids processing vessel body section 356 to the diameter of the outer segment 332 of the riser such that the solids processing vessel transition section 358 projects inwardly from the solids processing vessel section 356 to the outer segment 332 of the riser.

It should be understood that the solid particle treatment vessel 350 and the riser 330 may be subject to thermal expansion and, as described above, may be supported by spring supports 188. In addition, in one or more embodiments, the solid particle treatment vessel 350 may be connected to the riser 330 by means of a thermally compensating connection. For example, the thermally compensating connection may be located between the solid particle treatment vessel 350 and the outer segment 332 of the riser.

As shown in FIG. 1, the solid particle separation section 310 includes an outer shell 312 defining an inner region 314 of the solid particle separation section 310. The outer shell 312 may comprise a gas outlet port 316, a riser opening 318, and a solid particle outlet port 322. In addition, the outer shell 312 may comprise a gas/solid particle separation device 320 and a solid particle collection zone 380 in the inner region 314 of the solid particle separation section 310.

Similar to reactor section 200, outer shell 312 of solid particle separation section 310 may form an upper segment 376, a middle segment 374, and a lower segment 372 of solid particle separation section 310, as described above with respect to solid particle separation section 210.

As shown in FIG. 1, the riser 330 extends into the interior region 314 of the regeneration section 300 through the riser opening 318. In one or more embodiments, the riser 330 can extend through the riser opening 318 in a non-vertical direction. In one or more embodiments, the interior segment 334 of the riser does not extend through the lower segment 372 of the solids separation section 310.

As shown in FIG. 1, the outer shell 312 may further comprise a riser end device 378. The riser end device may be located near the inner riser segment 334. The gas and solid particles passing through the riser 330 may be at least partially separated by the riser end device 378. The gas and the remaining solid particles may be transported to a secondary separation device 320 in the solid particle separation section 310. The secondary separation device 320 may be any device suitable for separating solid particles from gases, such as a cyclone or a series of cyclones, as described above herein in relation to the gas/solid particle separation device 220. The secondary separation device 320 may deposit the separated solid particles in the lower portion of the upper segment 376, the middle segment 374, or the lower segment 372 of the solid particle separation section 310. In this way, solid particles can move under the action of gravity from the lower part of the upper segment 376 or the middle segment 374 to the lower segment 372.

The lower segment 372 of the solid particle separation section 310 may comprise a solid particle collection zone 380 that may allow solid particles to accumulate in the lower segment 372. In one or more embodiments, the solid particle collection zone 380 may comprise one or more of an oxygen scavenging zone, an oxygen separation zone, and a recovery zone. The solid particle collection zone 380 may further comprise a solid particle outlet port 322 similar to the solid particle outlet port 222 described above herein.

In one or more embodiments, the passageway 124 may be in fluid communication with the solids outlet port 322, and the regenerated solids may be moved from the regeneration section 300 to the reactor section 200 through the passageway 124. In this manner, the solids may be continuously recirculated through the reactor system 100.

Examples

The following examples illustrate the disclosure but are not intended to limit the scope of the disclosure. The following examples describe characteristics of solid particle collection zones in accordance with one or more embodiments described herein.

Example 1. Feed residence time in the riser and propylene selectivity

In accordance with the embodiments described above in this document, the reactor system was modeled to analyze the effect of riser residence time on propylene selectivity during the propane dehydrogenation reaction. The modeling results, which compare the change in feedstock residence time in the riser with the change in propylene selectivity, are shown in Table 1.

Table 1

Δ residence time (seconds) Δ propylene selectivity (mol.%) -0.51 0.31 -0.76 0.44 -1.27 0.75

As shown in Table 1, as the residence time in the riser decreases, the selectivity to propylene increases. This is likely due to a decrease in the side reactions that can occur within the riser. As the residence time in the riser is reduced, the opportunity for these side reactions to occur is reduced, which in turn leads to an overall increase in the selectivity of the system to propylene. As described earlier in this document, the use of a riser that enters the solids separation section in a non-vertical position can provide a shorter riser length. Thus, the risers described herein provide an advantage over a traditional riser that enters the solids separation section vertically through the bottom of the solids separation section by having a shorter length and, thus, providing a shorter residence time during which undesirable side reactions can occur.

Example 2: Flow of solids through solids collection zones

A flow of solid particles through two solid particle collection zones was simulated. The first solid particle collection zone 410 is shown in FIG. 4 and has an annular shape with one outlet passage 420 located at the bottom of the solid particle collection zone 410. The outlet passage 420 was not located on the central axis 430 of the first solid particle collection zone 410. The first solid particle collection zone 410 also includes several chordal beam supports covered with a tunnel grate 440.

The second zone 510 of collecting solid particles is shown in FIG. 5 and has a cylindrical shape and an outlet passage 520 located in the lower part of the zone 510 of collecting solid particles. The outlet passage 520 is located on the central axis 530 of the second zone 510 of collecting solid particles. The second zone 510 of collecting solid particles also includes several chordal beam supports covered with a tunnel grate 540.

Computational fluid dynamics (CFD) simulations were performed to model the flow of solids through the first and second solids collection zones. Residence time distributions (RTDs) of the solids in each vessel were obtained. For the purposes of the simulations, the diameter of each of the first and second solids collection zones was set to 46 inches. The superficial gas velocity at the bottom of each vessel was 0.3 ft/s and the average solids flux was 3.4 lb/ ^ft2 /s. In addition, the average revolution period for the solids was 8 minutes.

CFD modeling for the first solids collection zone predicted that the shortest solids residence time should be approximately 30 seconds due to solids crossflow on the outlet side of the vessel. CFD modeling also predicted that approximately 42% of the solids should have a residence time of less than 4 minutes. CFD modeling for the second solids collection zone predicted that the shortest solids residence time should be greater than 1 minute and that only 30% of the solids should have a residence time of less than 4 minutes.

RTDs for the first and second solids collection zones are graphically depicted in FIG. 6. The RTD for the first solids collection zone is shown by line 610 and the RTD for the second solids collection zone is shown by line 620. Additionally shown for reference in FIG. 6 are the RTDs for a single continuous stirred tank reactor (CSTR) and for three CSTRs in series. The RTD for a single CSTR is shown by line 630 and the RTD for three CSTRs in series is shown by line 640. As shown in FIG. 6, the RTD for the first solids collection zone is comparable to the RTD for a single CSTR and the RTD for the second solids collection zone is comparable to the RTD for three CSTRs in series. The second solids collection zone provides an advantage over the first solids collection zone because the flow of solids through the second solids collection zone more closely resembles plug flow. Thus, fewer solids quickly leave the solids collection area and fewer solids are retained in the solids collection area for a longer period of time. This results in a more uniform treatment of the solids in the solids collection area.

In a first aspect of the present description, olefins can be obtained by a method comprising contacting a hydrocarbon-containing feed stream with solid particles in a reaction vessel. Contacting the hydrocarbon-containing feed stream with the solid particles can result in the hydrocarbon-containing feed stream reacting to form an olefin-containing product stream. The reaction vessel can be connected to a riser and the reaction vessel can have a maximum cross-sectional area that is at least 3 times the maximum cross-sectional area of the riser. The method can further comprise passing solid particles through the riser. The riser can pass through an opening of the riser in an outer shell of the solid separation section such that the riser can comprise an inner segment of the riser located in an inner region of the solid separation section and an outer segment of the riser located outside the outer shell of the solid separation section. The solid separation section can comprise at least an outer shell defining an inner region of the solid separation section. The outer shell can comprise a gas outlet port, a riser opening and a solid outlet port. The outer shell may comprise a gas/solid separation device and a solids collection zone in the interior of the solids separation section. The riser opening may be located on the side wall of the outer shell such that it is not located on the central vertical axis of the solids separation section. The method may further comprise separating solids from the olefin-containing product stream in the gas/solid separation device and passing the solids separated from the olefin-containing product stream into a solids collection zone located near the central vertical axis of the solids separation section.

The second aspect of the present description may include the first aspect, in which the riser extends through the riser opening in a non-vertical direction.

The third aspect of the present description may include any of the first or second aspects, in which the riser extends through the riser opening in a diagonal direction, wherein the diagonal direction is from 15 to 75 degrees from the vertical.

The fourth aspect of the present description may include any of the first through second aspects, wherein the riser extends through the riser opening in a substantially horizontal direction.

The fifth aspect of the present description may include any of the first to fourth aspects, wherein the inner segment of the riser comprises a vertical portion, a non-vertical portion near the riser opening, and a non-linear portion connecting the vertical portion and the non-vertical portion.

The sixth aspect of the present description may include any of the first to fifth aspects, wherein the outer segment of the riser comprises a vertical portion near the reaction vessel, a non-vertical portion near the opening of the riser, and a non-linear portion connecting the vertical portion and the non-vertical portion.

The seventh aspect of the present description may include any of the first to sixth aspects, wherein the reaction vessel functions as an intense fluidized, turbulent or boiling bed reactor and the riser functions as a dilute phase riser reactor.

The eighth aspect of the present description may include any one of the first to seventh aspects, wherein the maximum cross-sectional area of the outer shell of the upper section of the solid particle separation is 5 to 40 times the maximum cross-sectional area of the riser.

The ninth aspect of the present description may include any of the first to eighth aspects, wherein the reaction vessel comprises a reaction vessel body section and a reaction vessel transition section, wherein the reaction vessel transition section is located between the reaction vessel body section and the outer segment of the riser.

The tenth aspect of the present description may include a ninth aspect, wherein the reaction vessel body section has a diameter and a height such that the ratio of the diameter to the height of the reaction vessel body section is from 5:1 to 1:5.

The eleventh aspect of the present description may include any of the first to tenth aspects, wherein the reaction vessel is supported by spring supports.

The twelfth aspect of the present description may include any of the first to eleventh aspects, wherein the reaction vessel is connected to the vertical portion of the outer segment of the riser via a thermal compensation connection.

The thirteenth aspect of the present disclosure may include any of the first to twelfth aspects, wherein the gas/solid particle separation device comprises one or more cyclones.

The fourteenth aspect of the present description may include any of the first through thirteenth aspects, wherein the riser does not pass through the solids collection zone.

The fifteenth aspect of the present description may include any of the first to fourteenth aspects, wherein the solid particle collection zone comprises a stripping device.

The subject matter of the invention herein is described in detail and with reference to specific embodiments. It should be understood that any detailed description of a component or feature of an embodiment does not necessarily imply that the component or feature is essential to the particular embodiment or any other embodiment. Furthermore, it will be apparent to those skilled in the art that various modifications and changes can be made to the described embodiments without departing from the spirit and scope of the claimed subject matter.

For the purposes of describing and defining the present specification, it should be noted that the terms "about" or "approximately" are used in the present specification to represent the inherent degree of uncertainty that may characterize any quantitative comparison, value, measurement or other representation. The terms "about" and/or "approximately" are also used in the present specification to represent the degree to which a quantitative representation may differ from a specified standard without altering the essential function of the subject matter of the invention.

It should be noted that in one or more of the following claims, the term "in which" is used as a transition phrase. For the purpose of disclosing the content of this technology, it should be noted that this term is used in the claims as a generic transition phrase that serves to represent a number of design characteristics, and it should be understood similarly to the more widely used generic introductory term "comprising".

It should be understood that where a first component is described as "comprising" a second component, it is intended that in some embodiments the first component "consists of" or "consists essentially of" the second component. It should also be understood that where a first component is described as "comprising" a second component, it is intended that in some embodiments the first component contains at least 10%, at least 20%, at least 30%, at least 40%, at least 50%, at least 60%, at least 70%, at least 80%, at least 90%, at least 95%, or even at least 99% of such second component (where % may mean weight % or mole %).

In addition, as used in this description, the term "consisting essentially of" refers to quantitative values that do not materially affect the basic and novel characteristics of the description. For example, it should be understood that a chemical composition "consisting essentially of" a particular chemical component or group of chemical components means that the composition includes at least about 99.5% of that particular chemical component or group of chemical components.

It should be understood that any two quantitative values assigned to a property may represent a range of that property, and all combinations of ranges formed from all specified quantitative values of a given property are contemplated in the present description. It should be understood that ranges of the component composition of a chemical component in a composition should be considered to contain, in some embodiments, a mixture of isomers of that component. In further embodiments, chemical compounds may be present in alternative forms, such as derivatives, salts, hydroxides, and the like.

Claims (18)

1. A method for producing olefins, comprising: bringing a hydrocarbon-containing feedstock stream into contact with solid particles in a reaction vessel, wherein the solid particles react with the hydrocarbon-containing feedstock stream to form an olefin-containing product stream, wherein the reaction vessel is connected to a riser, wherein the reaction vessel has a maximum cross-sectional area that is at least 3 times greater than the maximum cross-sectional area of the riser, and wherein the reaction vessel functions as a reactor with an intensive fluidized, turbulent or boiling bed, and the riser functions as a dilute phase riser reactor; passing solid particles through a riser, wherein the riser passes through a riser opening in an outer shell of the solid particle separation section in such a way that the riser comprises an inner riser segment located in an inner region of the solid particle separation section and an outer riser segment located outside the outer shell of the solid particle separation section, wherein the solid particle separation section comprises at least an outer shell defining an inner region of the solid particle separation section, wherein the outer shell comprises a gas outlet port, a riser opening and a solid particle outlet port, and wherein the outer shell comprises a gas/solid particle separation device and a solid particle collection zone in the inner region of the solid particle separation section, and wherein the riser opening is located on a side wall of the outer shell in such a way that it is not located on a central vertical axis of the solid particle separation section; separating solids from the olefin-containing product stream in a gas/solids separation device; and passing solid particles separated from the olefin-containing product stream into a solid particle collection zone located near the central vertical axis of the solid particle separation section. 2. The method according to claim 1, wherein the riser passes through the riser opening in a non-vertical direction. 3. The method of any one of the preceding claims, wherein the riser passes through the riser opening in a diagonal direction, the diagonal direction being from 15 to 75 degrees from vertical. 4. The method according to any one of claims 1 or 2, wherein the riser passes through the riser opening in a substantially horizontal direction. 5. A method according to any one of the preceding claims, wherein the internal segment of the riser comprises a vertical section, a non-vertical section near the opening of the riser, and a non-linear section connecting the vertical section and the non-vertical section. 6. A method according to any one of the preceding claims, wherein the outer segment of the riser comprises a vertical section near the reaction vessel, a non-vertical section near the opening of the riser, and a non-linear section connecting the vertical section and the non-vertical section. 7. The method of any one of the preceding claims, wherein the maximum cross-sectional area of the outer shell of the upper section of the solids separation is 5 to 40 times the maximum cross-sectional area of the riser. 8. A method according to any one of the preceding claims, wherein the reaction vessel comprises a reaction vessel body section and a reaction vessel transition section, wherein the reaction vessel transition section is located between the reaction vessel body section and the outer segment of the riser. 9. The method according to claim 8, wherein the section of the reaction vessel body has a diameter and height such that the ratio of the diameter to the height of the section of the reaction vessel body is from 5:1 to 1:5. 10. A method according to any of the preceding claims, wherein the reaction vessel is supported by spring supports. 11. A method according to any of the preceding claims, wherein the reaction vessel is connected to the vertical section of the outer segment of the riser by means of a thermal compensation connection. 12. A method according to any one of the preceding claims, wherein the gas/solid separation device comprises one or more cyclones. 13. The method of any one of the preceding claims, wherein the riser does not pass through a solids collection area. 14. A method according to any one of the preceding claims, wherein the solids collection zone comprises a stripping device.