Suppression of coke formation in hydrocarbon processing plant

Abstract

A process for reducing coke formation during thermal or thermochemical conversion of a hydrocarbon feedstock in a gaseous diluent using a rotating reactor is provided. The method comprises supplying an amount of additional gaseous diluent into a high temperature zone (10) of the reactor in which conditions are established for the thermal or thermochemical conversion to occur. In these regions, the additional gaseous diluent is supplied into the reaction space through perforations and / or pores (11) located in the stationary blades (2, 4) or other surfaces (7, 7A) surrounding the process fluid flow. A rotating apparatus configured to implement the method is also provided.

Description

Technical Field

[0001] The present invention relates generally to inhibiting carbonaceous deposition during thermal or thermochemical conversion of hydrocarbon feedstocks. In particular, the present invention relates to a method for reducing the formation of coke and other foulants on the surfaces of rotating bladed reactors designed for steam cracking. Background Art

[0002] Light olefins, such as ethylene and propylene, are widely used in the petrochemical and chemical industries to produce a variety of ingredients, including polymers, plastics, synthetic fibers and rubber. Ethylene is an essential compound used as a raw material for the manufacture of important industrial chemicals, including polyethylene, ethylene oxide, vinyl chloride, vinyl acetate, etc., and is a key ingredient in the petrochemical supply chain used to manufacture bulk commodities, such as plastic products, fibers, paints, coatings, detergents, solvents and packaging materials.

[0003] Traditionally, the conversion of common feeds such as diesel, naphtha, liquefied petroleum gas (LPG) and ethane to ethylene is carried out using thermal or catalytic conversion processes. The thermal degradation process using steam as a diluent medium is called steam cracking or pyrolysis. In a conventional tubular cracking furnace, the hydrocarbon feed and steam are first mixed and preheated in the convection section and then enter the radiant section (radiant coils) of the furnace where the cracking reaction takes place at about 700-900°C with residence times ranging from a few seconds to a fraction of a second.

[0004] Rotary reactor technology has been successfully used in steam cracking as an alternative to tubular furnaces. For example, in US 9,494,038 (Bushuev), US 9,234,140 ( Various rotating reactor configurations are described in US 9,494,038 (Xu & Rosic et al.) and US 10,744,480 (Xu & Rosic). Among them, US 9,494,038 and US 9,234,140 relate to rotating reactors comprising a rotor disk with associated blade cascades disposed between rows of stationary blades (stator cascades) arranged on a substantially annular support and enclosed in an annular gas housing. US 9,234,140 also outlines an axial reactor in which the rotating blades and the stationary blades are arranged in a substantially tubular housing, while US 10,744,480 describes a radial flow type reactor configuration.

[0005] In all the mentioned rotary devices, the hydrocarbon feed diluted with steam enters the reaction space formed by the reactor interior and passes through the fixed blades and the rotor blade rows several times before leaving the reactor. While propagating through the fixed blades and the rotating blade rows in the reactor space, the process fluid is heated to a temperature at which the feed hydrocarbons decompose to produce lower molecular weight hydrocarbons.

[0006] An unavoidable constraint of thermal cracking / pyrolysis is the formation and accumulation of carbonaceous deposits (mainly coke). The formation of coke negatively affects the process gas conversion and reduces the yield of the target olefins. In the above-mentioned rotary reactor design, heat is directly transferred to the gas flow, and the coke layer formed on the reactor surface causes distortion of the flow channel shape including the blades. As a result, the gas dynamic efficiency of the reactor decreases, the reactor shaft power decreases, and the temperature at the reactor exit decreases. The non-optimal temperature profile leads to a decrease in the yield of the target pyrolysis product. On the other hand, in conventional tubular cracking furnaces, the coke layer formed on the reactor surface hinders heat transfer through the reactor wall, which may lead to increased greenhouse gas emissions.

[0007] However, frequent decoking using conventional methods, such as burning a mixture of high-pressure air and steam (temperatures up to about 900°C), shortens the service life of the cracking equipment. In addition, decoking requires the production line to be stopped for about 20-40 hours, which has a considerable adverse effect on the economics of the process.

[0008] In the above rotating reactor design, coke formation is most intense in the region of the reactor where the reaction temperature exceeds about 750-850° C. This is also the region where the cracking reactions are most intense.

[0009] Steam acts as a diluent medium to reduce the rate of the cracking reaction by reducing the partial pressure of hydrocarbons, thereby increasing the selectivity of the target olefin (e.g., ethylene) and reducing coke deposition on the reactor surface. In known solutions, steam is added to the hydrocarbon feed before it enters the reaction zone. The maximum product capacity is then determined by calculating the optimal reaction temperature, feed temperature (preheating), and steam to hydrocarbon ratio.

[0010] However, the development of improved methods to prevent coke formation in thermal cracking plants remains a state-of-the-art challenge, especially with a view to optimizing and improving the energy and cost efficiency of industrial-scale ethylene production. Summary of the invention

[0011] The object of the present invention is to solve or at least alleviate the problems caused by the limitations and disadvantages of the related art. This object is achieved by various embodiments of methods and related apparatuses for reducing coke formation during thermal or thermochemical conversion of hydrocarbon feedstocks.

[0012] In one aspect, according to the definition in independent claim 1, there is provided a method for reducing coke formation during thermal or thermochemical conversion of a hydrocarbon feedstock using a rotary reactor in the presence of steam.

[0013] In an embodiment, a method for reducing coke formation during thermal or thermochemical conversion of a hydrocarbon feedstock using a rotary reactor in the presence of steam is provided, the rotary reactor comprising a rotor having a plurality of rotor blades arranged in at least one row on a circumference of a rotor hub mounted to a rotor shaft, and a plurality of stationary vanes arranged adjacent to the at least one row of rotor blades, wherein the rotor and the plurality of stationary vanes are enclosed in a conduit formed in a housing between at least one inlet and at least one outlet, the method comprising:

[0014] supplying, during the propagation of the process fluid provided as a mixture of hydrocarbon feed and dilution steam in said conduit between at least one inlet and at least one outlet, an amount of additional steam into one or more conduit zones in which conditions are established for thermal or thermochemical conversion to occur in said process fluid,

[0015] The additional steam is supplied into the duct through perforations and / or porous surfaces arranged on selected portions of the duct and / or on stationary vanes.

[0016] Additionally or alternatively, a supply of additional steam may be effected via at least some of the rotor blades.

[0017] In an embodiment, the method comprises supplying said amount of additional steam to said process fluid propagating through said conduit region, wherein a reaction temperature equals or exceeds a value of about 750 degrees Celsius (°C).

[0018] In an embodiment, the method comprises supplying said quantity of additional steam into said conduit region housing the last working stages of said rotary reactor.

[0019] In an embodiment, the method comprises supplying said amount of additional steam into said duct through perforated and / or porous surfaces arranged on a stationary guide vane upstream of said rotor blade and optionally on a stationary diffuser vane downstream of said rotor blade.

[0020] In an embodiment, the method comprises supplying said amount of additional steam into said conduit through a perforated and / or porous surface arranged on a selected portion of said conduit facing the process fluid flow.

[0021] In an embodiment, the method comprises supplying said quantity of additional steam into said duct through a perforated and / or porous surface arranged along a duct-defining inner wall of said housing.

[0022] In an embodiment, the method comprises supplying said amount of additional steam into said conduit through a perforated and / or porous surface arranged along a conduit-defining wall of a flow shaping device.

[0023] In an embodiment, the method comprises directing said amount of additional steam to the perforated and / or porous surface via a plurality of distribution channels connected to one or more external steam sources.

[0024] In an embodiment, the perforated and / or porous surface is composed of a composite material, a metal, a metal alloy, a ceramic, a cermet, or a combination thereof.

[0025] In an embodiment, the method further comprises: reducing the amount of steam at the reactor inlet.

[0026] In embodiments, the amount of additional steam is up to about 30% of the total amount of steam used in the thermal conversion or thermochemical conversion process.

[0027] In embodiments, the temperature of the additional steam supplied to the conduit is adjusted to be lower than the temperature of the process fluid stream to cool parts and components of the rotating reactor.

[0028] In an embodiment, the thermal or thermochemical conversion of the hydrocarbon feedstock is steam cracking of the hydrocarbon feedstock to produce olefins, such as ethylene and propylene.

[0029] In another aspect, according to the definition in independent claim 14, a rotary reactor for thermal or thermochemical conversion of a hydrocarbon feedstock in the presence of steam is provided with steam delivery means.

[0030] In another aspect, according to the definition in independent claim 15, there is provided a rotating reactor for thermal or thermochemical conversion of a hydrocarbon-containing feedstock in a gaseous diluent.

[0031] In an embodiment, the rotating reactor comprises a steam delivery device according to one of the previous aspects.

[0032] The utility of the present invention arises from a variety of reasons, depending on each of its specific embodiments. First, the proposed method allows the formation and accumulation of carbonaceous deposits (e.g., coke and other foulants) on the reactor surface facing the process fluid flow to be effectively suppressed in a highly targeted manner. Those areas in the reactor where coke formation is most intense can be targeted. The method also enables fine-tuning of the steam to hydrocarbon ratio during the conversion process, which provides further flexibility for adjusting conversion and olefin yield.

[0033] The method is energy-efficient. The method can reduce the amount of dilution medium (e.g. steam) fed to the cracking process at the reactor inlet. The reduction in the amount of dilution steam at the reactor inlet is proportional to the amount of additional steam fed to the areas that are particularly prone to coke formation. In practice, this amount can be as high as 30-35%. Therefore, the process does not require the input of additional energy to heat the steam diluent. Therefore, the provision of additional steam separation equipment downstream of the cracking reactor can be omitted.

[0034] By effectively inhibiting scaling of the reactor surface, the method is able to maintain the gas dynamics of the reactor at a level required to maintain an optimal temperature distribution throughout the reaction space for a longer period of time, thereby extending the time span between decoking processes. Therefore, the present invention eliminates the need for frequent (every few weeks) decoking of the cracking reactor, thereby minimizing system downtime associated with decoking. Costs associated with maintenance and repair can be reduced, and the service life of the reactor can be greatly extended. In the absence of a coke layer on the reaction surface, the output of the desired product can also be maintained at a stable high level.

[0035] The term "number" herein refers to any positive integer starting from one (1), such as one, two or three. The term "plurality" herein refers to any positive integer starting from two (2), such as two, three or four. The terms "first" and "second" as used herein are used solely to distinguish one element from another and do not denote any particular order or importance unless expressly stated otherwise.

[0036] In the present disclosure, the working blades or rotating blades of the turbine type reactor are mainly referred to by the term "blades"; and the stationary blades are mainly referred to by the term "vanes".

[0037] The term "gasification" is used herein to mean the conversion of matter into a gaseous state by any possible means.

[0038] Various embodiments of the invention will become apparent by consideration of the detailed description and accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1A is a vertical cross-sectional view of a reactor apparatus 100 , 100A for carrying out a method according to an embodiment. Figure 1B Shown along Figure 1A 100A and 100B are cross-sectional views taken along designated lines AA and BB, and illustrate a flow diagram of a streamlined path through reactor 100, 100A.

[0040] Figure 2A , Figure 2B and Figure 2Care vertical cross-sectional views of reactor devices 100 ( 100B, 100C, and 100D, respectively) for implementing a method according to an embodiment.

[0041] Figure 3A , Figure 3B and Figure 3C Steam supply devices installed in the reactor apparatus 100 are shown, embodied as 100A, 100B and 100C respectively. DETAILED DESCRIPTION

[0042] This article discloses detailed embodiments of the present invention in conjunction with the accompanying drawings. In all drawings, the same reference numerals represent the same components, wherein:

[0043] 100, 100A, 100B, 100C, 100D – reactor equipment;

[0044] 1 – rotor shaft;

[0045] 2, 4 – fixed blade cascade and associated fixed blades;

[0046] 3 – rotor blade cascade and associated rotor blades;

[0047] 3A – rotor hub / rotor disk;

[0048] 5 – flow shaping device;

[0049] 6 – gas housing;

[0050] 7, 7A – pipe and its bladeless part respectively;

[0051] 8, 8A, 8B – entrance;

[0052] 9, 9A, 9B – Exit;

[0053] 10 – high temperature area;

[0054] 11 – perforated and / or porous surface for conveying additional dilution medium into the pipeline;

[0055] 12, 12A, 12B—supply and distribution channels for directing additional dilution medium to the porous and / or perforated surface, wherein 12B denotes a distribution space provided as an extension of the branch channel 12A;

[0056] 13 – driving engine;

[0057] 14 – Shell of the reactor.

[0058] The present invention relates to a method for preventing or at least significantly reducing the formation and accumulation of carbonaceous deposits on the surfaces of feedstock processing equipment for thermal and / or chemical conversion of hydrocarbon feedstocks, wherein the feed enters the reaction space as a mixture of hydrocarbons and a dilution medium. In particular, the method allows for efficient suppression of fouling and coke formation within a rotating reactor configured for thermal / thermochemical processing of hydrocarbon feedstocks. The conversion may include thermal or thermochemical degradation reactions that occur when the mixture of hydrocarbon feedstock and dilution medium propagates through the reaction space.

[0059] The method comprises supplying a certain amount of additional dilution medium (diluent) into one or more regions of the reaction space where conditions for thermal or thermochemical conversion are established. These regions are respectively the regions where the highest severity operating conditions are achieved and the regions where the reaction temperatures are highest. Since the hydrocarbon feedstock conversion reactions are most intense in the high severity / high temperature regions, the regions are particularly susceptible to fouling due to the formation and accumulation of carbonaceous deposits such as coke. In some cases, the high temperature regions are also the regions where the feed conversion is the highest.

[0060] High temperature area Figure 1B and Figures 2A-2C 10. Conditions for thermal or thermochemical conversion to occur are established in zone 10. In an embodiment, such conditions are established when the temperature of the process fluid stream propagating through the reactor reaches a value in the range of at least about 700-750 degrees Celsius (° C.). Depending on the feedstock, the reaction temperature is in the region of about 700° C. to about 950° C.

[0061] In this context, the term "additional" refers to the amount of dilution medium supplied to the reaction space in addition to the "primary" diluent mixed with the hydrocarbon feed at the reactor inlet. In the described embodiments, the additional diluent and the primary diluent are preferably identical (have the same material composition).

[0062] Where appropriate, alternative arrangements are envisaged in which the additional diluent differs from the primary diluent in material composition.

[0063] In an embodiment, the disclosed method is used for a process for thermal or thermochemical cracking of a hydrocarbon feedstock in the presence of a gaseous diluent. In an embodiment, the gaseous diluent is (water) steam. In an embodiment, steam is used as a diluent medium for the hydrocarbon feed at the reactor inlet and as an additional diluent for delivery to the high temperature regions of the reaction space in a targeted manner. The disclosed method can be advantageously used for steam cracking of a hydrocarbon feedstock to produce lower molecular weight products.

[0064] In embodiments, hydrocarbon feedstocks include, but are not limited to, naphtha and gas oil, liquefied petroleum gas / LPG (LPG: propane and butane) and natural gas liquids / NGL (ethane, propane, butane). Propane and heavier fractions may be further utilized. Other feedstocks may be used where appropriate.

[0065] The disclosed method can be implemented in a rotary turbine type reactor 100, which is configured for thermal or thermochemical conversion of hydrocarbon feedstocks, comprising: a shell having at least one inlet and at least one outlet; a rotor having a plurality of rotor blades, the plurality of rotor blades being arranged in at least one row around the circumference of a rotor hub mounted on a rotor shaft; and a plurality of stationary vanes arranged near the at least one row of rotor blades, wherein the rotor and the plurality of stationary vanes are enclosed in a conduit formed in the shell and between the at least one inlet and the at least one outlet.

[0066] Figure 1A , Figure 2A and Figure 2B Rotating reactor apparatus 100 embodied as 100A, 100B and 100C are shown, respectively, which are configured to employ the disclosed method. It is further assumed that, based on the following description, a person skilled in the art is able to practice the method in any other type of rotating reactor, such as Figure 2C The reactor 100D shown in FIG. 1 , as well as reactors not explicitly disclosed herein.

[0067] exist Figure 1A , Figure 3A In the reactor configuration shown in , the process fluid propagates between an inlet and an outlet along a flow path established according to a substantially spiral trajectory formed within a substantially annular housing, wherein the fluid flow passes sequentially through rows of fixed guide vanes, rotor blades, and fixed diffuser vanes. Such devices are described in Bushuev's U.S. Patent Nos. 9,494,038 and et al., U.S. Pat. No. 9,234,140. Figure 2A and Figure 3B An axial type reactor is shown, in which the rotating blades and the stationary blades are contained in a substantially tubular housing, as shown in FIG. As described in the disclosure of et al. Figure 2B and Figure 3C The configuration outlined in US Pat. No. 10,744,480 to Xu & Rosic is shown. The method according to the embodiments may further be implemented in a rotating reactor, as outlined in US Pat. No. 7,232,937 to Bushuev (not shown). The entire contents of the above documents are deemed to be incorporated herein by reference.

[0068] The following description refers to the reactor 100 in all configurations ( 100A, 100B, 100C, and 100D).

[0069] The reactor 100 comprises a rotor system (hereinafter referred to as rotor), comprising a rotor shaft 1 positioned along a horizontal (longitudinal) axis XX' and a plurality of rotor blades (also referred to as working blades) arranged in at least one row on the circumference of a rotor hub or rotor disk 3A mounted on the rotor shaft. The plurality of rotor blades arranged in (blade) rows form a rotor blade assembly or rotor blade cascade 3.

[0070] The rotor is driven by a drive engine, which may be any one of an electric motor, a gas or steam turbine, or any other suitable drive device. Suitable couplings arranged between the motor drive shaft and the rotor shaft and various appliances, such as power converters, controllers, etc., are not described herein. The drive engine is Figure 2A The upper part is indicated by reference numeral 13.

[0071] The reactor 100 also comprises a stationary (stator) part formed by several structures defining the reaction space, such as for example a casing 6 , and a plurality of stationary blades 2 , 4 .

[0072] The fixed blades are arranged in rows, respectively forming fixed blade cascades adjacent to the rotor blade cascades. The first fixed blade cascade 2 is arranged upstream of the rotor blade cascade 3, and the second fixed blade cascade 4 is arranged downstream of the rotor blade cascade.

[0073] The term "cascade" (blade crown) refers to a group of (working) blades mounted on the periphery of the rotor disk / rotor hub or (stationary) blades mounted directly or indirectly on the inner wall of the casing. For clarity, the stationary blades are referred to as "buckets" in this disclosure.

[0074] The terms "upstream" and "downstream" mean: substantially along the direction of fluid flow throughout the device (along the axis X-X', see Figure 1A , 2A , 2B), the spatial and / or functional arrangement of structural parts or components relative to predetermined parts or components (i.e. at least one rotor blade row / cascade).

[0075] The cascade arranged upstream of at least one row of rotor blades comprises a plurality of fixed guide vanes. The fixed guide vanes can be configured as fixed nozzle guide vanes (NGV). These vanes form a first fixed vane cascade 2, also referred to as a fixed guide vane cascade. The cascade arranged downstream of at least one row of rotor blades comprises a plurality of fixed diffuser vanes. These vanes form a second fixed vane cascade 4, also referred to as a fixed diffuser cascade. The rotor blade row (cascade) 3 is located substantially between the fixed blade rows 2 and 4, which together can be regarded as a stator-rotor-stator arrangement 2, 3, 4.

[0076] In certain configurations, the provision of the second fixed vane cascade 4 (diffuser) may be omitted.

[0077] The reactor comprises a gas-tight housing 6 (also called a gas housing or a pressure housing), in which an internal passage 7 is established in the form of a pipe or duct, distributed between at least one inlet 8 and at least one outlet 9. The inner surface of the housing 6 faces the duct 7. In some configurations, the duct 7 is defined by the inner surface of the housing. The shape of the duct / duct 7 varies depending on the reactor configuration.

[0078] In this disclosure, the gas housing 6 is generally referred to as a reactor housing. In practice, the reactor 100 may be further enclosed in a separate housing. Figure 2B A reactor having a housing 14 is shown.

[0079] Figure 1A A reactor having two inlets 8A, 8B and two outlets 9A, 9B is shown, while FIG. 2A to FIG. 2C A configuration is shown with one inlet 8 and one outlet 9. Any other configuration may be envisaged where appropriate. The inlet(s) and outlet(s) comprise relevant openings or ports in the housing 6 and a number of branches, sleeves or manifold channels associated with each of the ports.

[0080] The housing 6 is configured to substantially completely enclose the periphery of the rotor on which a plurality of moving blades are assembled to form at least one rotor blade cascade 3 and a plurality of stationary vanes 2, 4 arranged adjacent to the rotor blade cascade(s).

[0081] In the reactor 100, the arrangement of the blade rows 2, 3, 4 in the internal passage 7 in the casing 6 forms one or more bladeless portions 7A (so-called bladeless spaces) between the exit of the row of fixed diffuser vanes 4 arranged downstream of the rotor blades and the entry of the row of fixed guide vanes 2 arranged upstream of the rotor blades.

[0082] Reactor 100 is configured with several basic stages, also referred to as working stages or process stages. In certain configurations, each working stage is formed by a continuous row of blades, which includes fixed guide vanes 2, rotor blades 3 and optional fixed diffuser vanes 4. The reactor can be configured as a single-stage reactor or a multi-stage reactor. It is conceivable to have a multi-stage configuration including, for example, 2-10 rows of rotor blades mounted on a rotor shaft (see, for example, 100B, 100C, 100D). In this multi-stage configuration, each stage can be driven by the same or different (e.g., connected) rotor shafts.

[0083] Figure 1B , Figures 2A-2C The working levels are indicated by Roman numerals (i-vii).

[0084] The function of the basic stage is to transfer mechanical energy to the process fluid and further convert the mechanical energy into heat energy. During the energy conversion cycle, the row(s) of fixed guide blades 2 arranged upstream of the rotor blades 3 prepare the required flow conditions at the inlet of the rotating blade row (cascade). In the rotor blade row, the mechanical energy of the shaft and the rotating blades is transferred to the fluid flow. In at least part of each rotor blade row 3, the process fluid flow can reach supersonic flow conditions.

[0085] The row (or rows) of fixed blades (diffuser 4) arranged downstream of the rotor blades 3 convert the mechanical energy of the fluid into its thermal energy (heat). The fluid flow leaves the rotor blades 3 at supersonic speed and enters the diffuser 4. If the flow upstream of the diffuser is supersonic, the kinetic energy of the fluid flow is converted into the internal energy of the fluid by multiple impacts and a viscous mixing and dissipation system. The flow dissipates its kinetic energy into the internal energy of the fluid flow propagating through the reactor (along the pipeline 7), thereby providing a certain amount of thermal energy to the fluid. The increase in the internal energy of the fluid leads to an increase in the temperature of the fluid.

[0086] In fact, the fluid flow propagating through the reactor 100 passes through several working stages in sequence, and with each stage / passage, the temperature of the process fluid increases by a certain value. More precisely, the temperature increase occurs when the process fluid flow leaves the rotor blades and passes through the diffuser and / or the bladeless space. The temperature increase promotes the thermal degradation or thermochemical degradation of the feedstock material and converts it into the desired product. The amount of thermal energy added to the fluid is sufficient to trigger chemical degradation reactions, especially reactions that cause the chemical bonds between long carbon-carbon (CC) chains to break. Therefore, the size of high molecular weight compounds present in the fluid flow is effectively reduced. In the working stage, when the temperature and the conditions of the process flow are sufficient to cause thermal conversion or thermochemical conversion, a group (one or more) of chemical reactions that trigger the conversion of feed hydrocarbons into target products mainly occur in the bladeless portion 7A of the pipeline.

[0087] In a configuration without fixed diffuser vanes, a vaneless space is formed downstream of the rotor blade cascade. For example, Figure 2B The reactor 100C shown may adopt such a configuration (see stages i, iv-vii realized without diffuser vanes 4). In this case, the non-vaned portion of the pipe is configured in its three-dimensional shape to act as an energy converter and convert the mechanical energy transferred by the rotor to the process fluid into heat.

[0088] In reactor 100, the temperature increase can be optimized as desired. The temperature increase achieved in one stage can, for example, be in the range of about 10°C to about 120°C. Thus, in any of 100A-100D (all provided as multi-stage solutions), the fluid can be heated to about 1000°C in a "one-pass" configuration (100°C temperature increase per stage in a 10-stage device). Since the residence time spent by the reaction fluid through the reactor stage is on the order of a fraction of a second, for example, about 0.01-0.1 seconds, rapid and efficient heating can be achieved even in the most basic configuration.

[0089] In some cases, the reactor may include a so-called inlet stage and an optional outlet stage. The configuration of these stages may differ from that of the working stages.

[0090] As the process fluid (a mixture of hydrocarbon feed and gaseous diluent, such as steam) propagates through the working stages between the inlet and the outlet, its temperature gradually increases. The thermal conversion process (and thus thermal cracking, with the decomposition of the feed hydrocarbons into lower molecular weight products) occurs in a conduit zone (or zones) 10, where the severity of cracking is about its maximum or at least close to its maximum. The reaction temperature reaches at least 700-750° C. in these (one or more) conduit zones. Depending on the feedstock, the cracking is most intense in the reactor zone, where the flow of the process fluid reaches about 700-950° C.

[0091] For example, the conversion of light hydrocarbons (such as certain naphthas or ethane) to ethylene occurs at about 800-850° C. Within the same temperature range, near maximum cracking severity can be achieved, resulting in the highest ethylene yields.

[0092] The conduit region(s) 10 are therefore referred to as “high temperature region(s)”. Since the regions 10 accommodate the most intense reactions, these regions are also the high turbulence region(s).

[0093] Considering that the typical temperature distribution in the thermal conversion process (e.g., steam cracking) operated in the rotating device 100 (any of 100A-100D) is in the range of about 300-500°C at the inlet and about 800-1300°C at the outlet, the location of the (one or more) high temperature regions 10 in the reactor 100 corresponds to the last working stages (i.e., the last working stages near the one or more reactor outlets 8, 8A, 8B). In the piping area that usually accommodates the two to four last stages, the severity of the operating conditions (especially the temperature) reaches a level sufficient to allow the cracking reaction to occur and proceed at near maximum levels.

[0094] The reaction rate and optionally the feed conversion are highest in the region(s) 10. Therefore, the formation of coke and other foulants on the reactor surfaces facing the pipe 7 is most intense in the region 10. Within the region 10, stationary surfaces, such as the inner wall of the pipe 7 and the stationary blade cascades 2, 4, are particularly susceptible to coke formation.

[0095] It should be noted that the span of the high temperature region 10 within the reactor 100 / along the pipeline 7 is not limited to a specific number of final stages, but depends on the reactor configuration, the total number of (working) stages, reaction conditions, process feedstocks, etc.

[0096] refer to Figure 1A , wherein a reactor 100 of configuration 100A is shown, wherein the housing 6 has a substantially toroidal shape (a "donut" shape) in a three-dimensional configuration, whereby the rotor system (1, 3A, 3) with the associated bearing assembly (not shown) can be considered to fill the aperture defining the opening of the central portion of the toroid. In its meridian cross section, the housing 6 is substantially toroidal in shape.

[0097] In the reactor 100A, the stationary blade cascades 2 , 4 are arranged as a substantially annular assembly on both sides of the rotor blade cascade 3 .

[0098] The reactor in configuration 100A further comprises a flow shaping device (flow guiding device) 5 arranged in the gas housing 6. In 100A, the flow shaping device 5 is configured as an internal fixed annular structure, which explains the establishment of a substantially annular duct in the housing 6. The device 5 is fixed in the gas housing 6 with appropriate fixing means (not shown). In some configurations, the flow shaping device 5 can be provided as an annular, substantially hollow structure, such as, for example, a hoop.

[0099] In the case where the stator vanes are arranged on bearing blocks (not shown) constituting the rotor bearing system, the flow shaping device 5 can abut the tip of the rotor blade (forming a gap therebetween to allow the rotor to rotate unhindered) and the peripheral portion of the stator vane. Alternatively, the stator cascade can be assembled on the flow shaping device 5 in a manner adjacent to the rotor blade 3. Thus, the stator vanes can be mounted on the flow shaping device and / or connected to the flow shaping device by auxiliary means (e.g. rings, brackets, etc.) (not shown). The above features are described in Bushuev (US 9,494,038) and cited above. A more detailed discussion is provided in the patent literature of et al. (US 9,234,140).

[0100] In the reactor 100A, the internal passage is defined by the volume formed between the gas housing 6 (outer "donut") and the internal flow shaping device 5 (inner "donut"). Thus, this internal passage (duct 7) formed between the inner surface of the gas housing 6 and the outer surface of the flow shaping device 5 adopts a substantially annular shape, with a substantially annular meridian cross section.

[0101] Figure 1B The location of the high temperature zone(s) 10 in the reactor 100A is shown.

[0102] Figure 1B Shown along Figure 1A . The cross-sectional area along line AA is located at the inlet (entrance) of the fixed guide vane cascade 2, while the cross-sectional area along line BB is located at the exit of the fixed diffuser cascade 4. The cross-sectional areas AA and BB can also be considered to depict events occurring at the inlet and exit of the stator-rotor-stator arrangement.

[0103] The inlet (entrance) into the blade / vane cascade is usually defined by the leading edge of the associated blade / vane, whereas the exit from the cascade is defined by the trailing edge of said blade / vane. The inlet and exit are defined in the direction of fluid flow.

[0104] In reactor 100A, process fluid propagates in conduit 7 between pairs of inlets and outlets (8A and 9A, and 8B and 9B, respectively). Figure 1B Streamlines running between the first inlet 8A and the first outlet 9A are shown. Streamlines running between the second inlet 8B and the second outlet 9B are not shown.

[0105] In the reactor 100A, the process fluid stream containing the feedstock flows along a path established by a substantially spiral trajectory, wherein the process fluid successively passes through a number of working stages i-vii defined across rows of fixed guide vanes 2, rows of rotor blades 3 and rows of fixed diffuser vanes 4. Thus, the fluid leaving the fixed diffuser cascade 4 flows "upwards", passes through the vaneless space 7A and continues to flow to the fixed guide vane cascade 2 of the subsequent stage.

[0106] like Figure 1B As shown, the reaction is most intense in the region along the last three regenerative passes through the cascade 2, 3, 4 (stages v-vii). Thus, stages v-vii form a high temperature region 10.

[0107] Figure 2AA reactor 100 is shown in configuration 100B. The reactor 100B is configured as an axial reactor, which generally follows the design for an axial compressor or turbine. The reactor 100B comprises an elongated rotor 1 extending along a horizontal axis XX'. A plurality of rotor blades are arranged in several consecutive rows along the rotor hub to form (one or more) rotor blade cascades 3. The rotor 1 is enclosed in a housing 6, the inner surface of which is provided with a first fixed blade cascade 2 and a second fixed blade cascade 4, respectively, arranged so that the blades / vanes of the rotor and stator cascades 2, 3 and 4 alternate along the longitudinal direction of the rotor 1 (along the axis XX'). The rows of fixed vanes 2, 4 can be arranged on opposite sides of the (inner) surface of the housing facing the pipe. In this way, working stages i-vii are established, each of which is formed by a rotor blade cascade 3 and an adjacent pair of stator blades 2, 4. The portion 7A of the pipe without blades / vanes is arranged between subsequent stages.

[0108] The housing 6 may be tapered, or the housing 6 may be of substantially constant cross-section along its entire length (not shown).

[0109] Figure 2B A reactor 100 is shown in configuration 100C. Reactor 100C is configured as a radial turbine, generally following the design used for a centrifugal compressor or centrifugal pump. The term "centrifugal" means that the fluid flow within the device is radial; therefore, reactor 100C is referred to as a "radial flow device". Figure 2B The reactor shown comprises several working stages (i-vii), each of which is represented by a fixed guide vane cascade 2, a rotor blade cascade 3 and a fixed diffuser vane cascade 4. The diffuser is located in a substantially U-shaped duct provided as part of a conduit 7 followed by a vaneless section 7A. In certain configurations, the provision of diffuser vanes 4 can be omitted, in which case the vaneless U-shaped duct located downstream of the rotor blades can act as an energy converter.

[0110] In configurations 100B and 100C, the high temperature region 10 begins approximately between stages v and vi and extends to the last stage vii to the outlet 9. The span of the region 10 within the conduit may vary depending on the reactor configuration, the total number of stages, process conditions, etc.

[0111] Figure 2C Any other type of multi-stage rotating reactor apparatus is shown at 100D, which may be configured to employ methods according to embodiments. In the exemplary configuration 100D, the high temperature zone 10 is established by the last two stages (iv and v).

[0112] In order to inhibit the formation and accumulation of carbonaceous deposits, such as coke and other foulants, on the reactor surfaces in contact with the process fluid stream in the high temperature zone 10, it is proposed to supply a certain amount of additional gaseous diluent into the zone 10. The present invention is based on the observation that by supplying additional gaseous diluent into the conduit 7 via perforations and / or pores made in a selected structure in the high temperature zone 10, the formation of coke and other foulants can be prevented or at least significantly reduced.

[0113] When a hydrocarbonaceous process fluid (a mixture of hydrocarbon feed and a gaseous diluent such as steam) is propagated through conduit 7, injection of additional diluent into the process intensive high temperature zone 10 has proven beneficial in suppressing coke formation during thermal or thermochemical conversion of the hydrocarbon feedstock.

[0114] The amount of additional gaseous diluent injected into the process can reach 30-35% of the total amount of gaseous diluent. At the same time, the amount of gaseous diluent at the reactor inlet can be reduced. This allows to keep the overall energy consumption at the same level (since no additional dilution medium needs to be heated) and avoids the difficulties associated with downstream excess steam separation.

[0115] In an embodiment, the gaseous diluent is (water) steam. Injecting additional steam into the high temperature zone 10 can effectively suppress the formation of coke and other foulants in the steam cracking process for producing light olefins (such as ethylene and propylene).

[0116] The steam supplied as an additional dilution medium to the zone(s) 10 reduces the hydrocarbon partial pressure, thereby inhibiting or reducing the formation of coke deposits.

[0117] Steam as an additional diluent is delivered to the interior region 10 of the reactor 100 by a number of fixed structures, including selected portions of the conduit 7 facing the process fluid flow and / or fixed vanes 2, 4. In some cases, the additional diluent may be injected through the working / rotating blades. However, for the purposes of the present invention, fixed structures are preferred.

[0118] The selected portion of the conduit 7 includes the surface(s) defining the inner wall of the gas housing 6 (the inner surface of the gas housing), the surface of the flow shaping device 5 defining the conduit (see configuration 100A), and any other surface surrounding the process fluid flow.

[0119] The delivery of steam as an additional diluent into the duct 7 may be achieved by any one of the fixed guide vanes 2, the fixed diffuser vanes 4, the vaneless portion 7A of the duct 7 downstream of the diffuser vanes, or any combination thereof.

[0120] In order to deliver steam as an additional diluent to the high temperature region 10, the selected fixed structure or part thereof is made perforated and / or porous. The perforated and / or porous surface for delivering the additional diluent into the pipeline is Figure 3A , Figure 3B and Figure 3C It is marked with reference numeral 11.

[0121] Steam as an additional dilution medium is directed to the perforated and / or porous surface 11 via a plurality of distribution channels 12, 12A arranged in the stationary vanes 2, 4, the casing 6, the flow shaping device 5 or any combination thereof. The gaseous diluent can be fed into the high temperature zone 10 from the same source that supplies the dilution medium (e.g. steam) to mix with the hydrocarbon feed at the reactor inlet. In said zone 10, several distribution channels 12 can be arranged to receive the gaseous medium from an external source of the dilution medium (not shown). The channel 12 is advantageously arranged to branch into a plurality of branch channels 12A at desired locations (see Figure 3C ).

[0122] The supply and distribution channels 12, 12A may further be expanded to form a distribution space 12B on at least a portion of the structure having the perforated / porous surface 11 (see Figure 3C ) to close the surface(s) 11. By closing the perforated and / or porous surface 11, the gaseous diluent can be evenly distributed in the reaction space (i.e. in the duct 7 and its bladeless portion 7A) through the perforated / porous structure (11). The distribution space 12B can be provided as one or more extensions of the branch channel(s) 12A.

[0123] The distribution channels 12, 12A, 12B and the plurality of perforated and / or porous surfaces 11 together form a steam delivery device for the rotary reactor. In the device, the distribution channels 12, 12A, 12B are configured to deliver steam to the perforated and / or porous surfaces 11, which enables the steam to stay in the reaction space. The reaction space is defined by the inner space of the reactor, i.e. the pipe 7. The steam delivery device is preferably installed in the high temperature zone 10.

[0124] The diluent feed through the fixed blades 2, 4 is implemented so that the gaseous diluent is supplied into the blade chamber through the branch channel 12A, so that the diluent leaves the blade chamber (and enters the reaction space / duct 7) through a plurality of holes / apertures arranged in the blade wall. Figure 3A and Figure 3B (Figure below).

[0125] FIG. 3A to FIG. 3C Exemplary locations along the high temperature zone(s) 10 for supplying additional gaseous diluent to the reactor are shown. Figure 3A (Picture above), Figure 3B(picture above) and Figure 3C The flow of additional gaseous diluent is shown by arrows in FIG.

[0126] All or selected stationary blades in region 10 may be modified as follows. Any vertical surface of the blade shell, i.e., the pressure side (i.e., where the flow enters the blade and / or the suction side, i.e., where the fluid separates from the blade), may be made perforated or porous. In some cases, the entire blade shell may be made of a porous material.

[0127] Providing a perforated and / or porous surface 11 on the pressure side of the airfoil will create a diluent boundary level, thereby reducing the hydrocarbon concentration near the blade wall. All or selected fixed guide vanes and / or all or selected fixed diffuser vanes can be modified on the pressure side of the blade to have a perforated / porous surface 11. On the other hand, providing a surface 11 on the suction side can prevent the return vortex formed by the airflow leaving the blade from contacting the blade again. For all or selected fixed diffuser vanes, modification on the suction side may be preferred.

[0128] Additionally or alternatively, the housing 6 and flow shaping device 5 (if applicable) may be modified to incorporate perforated and / or porous surfaces 11. Within the region(s) 10, any surface of the conduit 7 enclosing the process fluid flow may be modified to include perforations and / or pores. For example, the surface 11 may be arranged in a flow separation region where the process flow is diverted after leaving the diffuser vanes (see Figure 3C , circled area 12B).

[0129] In general, the position of the perforated and / or porous surface 11 is optimized to prevent coke formation. For example, arranging the surface 11 on the suction side of the diffuser vane (where the airflow separates from the vane) is not used in conventional vane cooling.

[0130] The reactor portion including the perforated and / or porous surface 11 may be constructed of composite materials, metals, metal alloys, ceramics, cermets, or combinations thereof.

[0131] By controlling the flow rate of (additional) steam supplied to the surface 11 via the distribution channels 12, 12A, 12B, the formation of deposits on the reactor surface can be further prevented.

[0132] In this method, the temperature of the additional steam supplied to the zone(s) 10 is lower than or equal to the temperature of the process fluid. By adjusting the additional steam diluent stream injected into the conduit zone(s) 10 to a temperature lower than the process fluid stream flowing through the conduits, the additional steam can be used to cool parts and components of the reactor, including stationary and non-stationary components, such as stationary blades and rotor blades. The additional steam is typically injected at a pressure higher than the pressure of the process fluid stream.

[0133] In one aspect, a steam delivery device is provided for a rotary reactor 100 for thermal or thermochemical conversion of a hydrocarbon feedstock in the presence of steam, the device comprising: distribution channels 12, 12A, 12B, and a plurality of perforated and / or porous surfaces 11 arranged on selected portions of the stationary blades 2, 4 and / or the pipe 7, which defines the reaction space of the rotary reactor. The distribution channels 12, 12A, 12B are configured to deliver steam to the perforated and / or porous surfaces 11, which enables the steam to stay in the reaction space. The steam delivery device is installed in those sections of the rotary reactor that surround the (one or more) high temperature regions 10 of the reaction space, in which the conditions for thermal or thermochemical conversion to occur are established. In some cases, the elements 11, 12 of the steam delivery device can be incorporated into at least some of the rotor blades 3.

[0134] There is further provided the use of the steam delivery device for reducing coke formation in a rotating reactor 100 during thermal or thermochemical conversion of a hydrocarbon feedstock, optionally accompanied by cooling of reactor parts and components, wherein the reduction in coke formation and optional cooling is achieved by delivering a certain amount of additional steam into (one or more) high temperature zones 10 of the reaction space in the manner described above.

[0135] In one aspect, a rotary reactor 100 (100A, 100B, 100C, 100D) for thermal or thermochemical conversion of a hydrocarbon-containing feedstock in a gaseous diluent is provided, comprising: a housing 6 having at least one inlet 8 and at least one outlet 9; a rotor 1 having a plurality of rotor blades 3 arranged in at least one row on the circumference of a rotor hub mounted to a rotor shaft; and a plurality of stationary vanes 2, 4 arranged adjacent to the at least one row of rotor blades, wherein the rotor and the plurality of stationary vanes are enclosed in a conduit 7 formed in the housing and located between the at least one inlet and the at least one outlet. The reactor comprises a perforated and / or porous surface 11 arranged on selected portions of the conduit defining structure and / or on the stationary vanes 2, 4 to enable additional gaseous diluent to flow therethrough, wherein the perforated and / or porous surface is arranged in one or more high temperature regions 10 of the conduit where conditions are established for thermal or thermochemical conversion to occur.

[0136] In an embodiment, perforations and / or porous structured surfaces are integrated into all or selected stationary vanes and / or selected portions of the conduit wall facing the process fluid flow, and optionally into at least some of the rotor blades.

[0137] The reactor is configured for heat-assisted conversion of feedstock in a fluid dilution medium, particularly for thermal or thermochemical cracking of hydrocarbonaceous feedstock. The cracking process involves fluidized hydrocarbonaceous feedstock (i.e., a fluidized organic feedstock material that primarily contains carbon and hydrogen). In an embodiment, the process is steam cracking of a hydrocarbonaceous feedstock to produce olefins, such as ethylene and propylene.

[0138] Additionally or alternatively, the heat-assisted conversion of the feedstock may involve processing organic feedstocks. In some configurations, the reactor 100 may be suitable for processing cellulose-based feedstocks. In some additional or alternative configurations, the device 100 may be suitable for processing feedstocks based on (waste) animal fats and / or (waste) vegetable oils. The pretreatment of the animal fat and vegetable oil-based feedstocks may include hydrodeoxygenation (removing oxygen from oxygenated compounds), which results in the decomposition of the (tri)glyceride structure and the production of mainly straight-chain alkanes. In further additional or alternative configurations, the reactor 100 may be suitable for processing byproducts of the wood pulp industry, such as tall oil or any derivatives thereof.

[0139] Thus, in some cases, the hydrocarbon-containing feed may be a gasified pretreated biomass material (cellulose or lignocellulose derived pretreated biomass, supplied to the reactor in a substantially gaseous form). Other organic feedstocks may include pretreated glyceride-based materials, such as (waste or residual) vegetable oils and / or animal fats, or pretreated plastic waste or residues. The pretreatment of the (tri)glyceride-based feedstock may include different processes, such as pyrolysis or deoxygenation as described above. A range of plastic wastes (including PVC, PE, PP, PS materials and mixtures thereof) may be used in processes for recovering pyrolysis oil or gas, which may be further used as a feedstock for the production of new plastics and / or refined into fuel oil (diesel equivalent).

[0140] Thus, the reactor 100 can be configured to perform at least one process selected from the following groups: processing a hydrocarbon feedstock preferably containing medium and light hydrocarbon fractions; processing a gasified carbohydrate-containing feedstock material, processing a gasified glyceride and / or fatty acid-containing feedstock material, and processing a gasified cellulosic biomass material.

[0141] In the case of using organic feedstocks, the reactor 100 can further be adapted for catalytic processes. This is achieved by contacting the process fluid with a plurality of optional catalytic surfaces (not shown) formed by the catalytic coating of the blades or inner walls. In some cases, the device can include a plurality of catalytic modules defined by a ceramic or metal matrix or carrier with an active (catalytic) coating, optionally implemented as a monolithic honeycomb structure.

[0142] It is clear to a person skilled in the art that, as technology advances, the basic idea of ​​the invention can be implemented in various ways. The invention and its embodiments may generally vary within the scope of the appended claims.

Claims

1. A method for reducing coke formation during thermal or thermochemical conversion of a hydrocarbon feedstock in the presence of steam using a rotary reactor (100), the rotary reactor comprising: A rotor (1) having a plurality of rotor blades (3) arranged in at least one row on the circumference of a rotor hub mounted on a rotor shaft, and a plurality of stationary vanes (2, 4) arranged adjacent to the at least one row of rotor blades, wherein the rotor and the plurality of stationary vanes are enclosed in a duct (7) formed in a housing (6) between at least one inlet (8) and at least one outlet (9), the method comprising: During the propagation of the process fluid provided as a mixture of hydrocarbon feed and dilution steam in the conduit (7) between at least one inlet and at least one outlet, a quantity of additional steam is supplied to one or more conduit areas (10) in which conditions are established for thermal or thermochemical conversion to occur in the process fluid, Therein, the additional steam is supplied to the duct through perforations and / or porous surfaces (11) arranged on selected portions of the duct and / or on the stationary blades (2, 4).

2. The method according to claim 1, comprising: The amount of additional steam is supplied to the process fluid propagating through the conduit region (10) wherein a reaction temperature equals or exceeds a value of about 750 degrees Celsius (°C).

3. The method according to any one of claims 1 or 2, comprising: The additional quantity of steam is supplied to a pipe area (10) housing the last working stages of the rotary reactor.

4. A method according to any one of the preceding claims, wherein: The amount of additional steam is supplied to the duct via a perforated and / or porous surface (11) which is arranged on a fixed guide vane (2) upstream of the rotor blade (3) and optionally on a fixed diffuser vane (4) downstream of the rotor blade.

5. A method according to any one of the preceding claims, wherein: The amount of additional steam is supplied into the conduit through a perforated and / or porous surface (11) arranged on a selected portion of the conduit facing the process fluid flow.

6. A method according to any one of the preceding claims, wherein: The additional quantity of steam is supplied into the duct via a perforated and / or porous surface (11) arranged along the duct-defining inner wall of the housing (6).

7. A method according to any one of the preceding claims, wherein: The amount of additional steam is supplied into the conduit via a perforated and / or porous surface (11) arranged along a conduit-defining wall of the flow shaping device (5).

8. A method according to any one of the preceding claims, wherein: The amount of additional steam is directed to the perforated and / or porous surface (11) via several distribution channels (12, 12A, 12B) connected to a steam source.

9. A method according to any one of the preceding claims, wherein: The perforated and / or porous surface is composed of a composite material, a metal, a metal alloy, a ceramic, a cermet, or a combination thereof.

10. The method according to any one of the preceding claims, further comprising: The amount of steam at the one or more reactor inlets (8, 8A, 8B) is reduced.

11. A method according to any one of the preceding claims, wherein: The amount of additional steam may be up to about 30% of the total amount of steam used in the thermal or thermochemical conversion process.

12. A method according to any one of the preceding claims, wherein: The temperature of the additional steam supplied to the conduit is adjusted to be lower than the temperature of the process fluid stream to cool parts and components of the rotating reactor.

13. A method according to any one of the preceding claims, wherein: Thermal or thermochemical conversion of hydrocarbon feedstocks is the steam cracking of hydrocarbon feedstocks to produce olefins, such as ethylene and propylene.

14. A steam delivery device for use in a rotary reactor (100) for use in thermal or thermochemical conversion of a hydrocarbon feedstock in the presence of steam, the device comprising: distribution channels (12, 12A, 12B), and several perforated and / or porous surfaces (11) arranged on selected parts of a pipe (7) defining a reaction space of the rotary reactor and / or on several fixed blades (2, 4) of the rotary reactor, wherein the distribution channels (12, 12A, 12B) are configured to deliver steam to the perforated and / or porous surface (11), which enables the steam to flow to the reaction space, The device is installed in a section of the rotary reactor that surrounds a region (10) in the reaction space where conditions for thermal or thermochemical conversion are established.

15. A rotary reactor (100) for thermally converting or thermochemically converting a hydrocarbon-containing feedstock in a gaseous diluent, the rotary reactor comprising: a housing (6) having at least one inlet (8) and at least one outlet (9), A rotor (1) having a plurality of rotor blades (3) arranged in at least one row on the circumference of a rotor hub mounted on a rotor shaft, and a plurality of fixed blades (2, 4), wherein the plurality of fixed blades (2, 4) are arranged near the at least one row of rotor blades, wherein the rotor and the plurality of stationary blades are enclosed in a duct (7) formed in the housing between at least one inlet and at least one outlet, Therein, the reactor comprises perforated and / or porous surfaces (11) arranged on selected portions of the pipe and / or on fixed blades (2, 4) to enable additional gaseous diluent to flow therethrough, wherein the perforated and / or porous surfaces are arranged in one or more pipe regions (10) where conditions for thermal or thermochemical conversion occur.

16. The rotary reactor according to claim 15, wherein: The perforated and / or porous surface (11) is composed of composite materials, metals, metal alloys, ceramics, cermets or combinations thereof.

17. A rotary reactor (100) for thermally converting or thermochemically converting a hydrocarbon-containing feedstock in the presence of steam, the rotary reactor comprising the steam delivery device according to claim 14.

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