Suppression of Coke Formation in Hydrocarbon Processing Equipment

Abstract

A method is provided for reducing coke formation during the thermal or thermochemical conversion of a hydrocarbon-containing feedstock in a gaseous diluent using a rotary reactor. The method includes supplying an additional amount of gaseous diluent into a high temperature region (10) of the reactor where conditions for the thermal or thermochemical conversion occur. Within these regions, the additional gaseous diluent is supplied into the reaction space through perforations and / or holes (11) formed within stationary blades (2, 4) or other surfaces (7, 7A) that confine the process fluid flow. A rotary device formed to carry out the method is further provided.

Description

Technical Field

[0001] Broadly speaking, the present invention relates to suppressing carbonaceous deposits in processes for the thermal or thermochemical conversion of hydrocarbon feedstocks. Specifically, the present invention relates to a method for reducing the formation of coke and other foulants on the surface of a rotating reactor with blades designed for steam cracking.

Background Art

[0002] Light olefins, such as ethylene and propylene, are widely used in the petrochemical and chemical industries for the production of various components including polymers, plastics, synthetic fibers, and rubbers. Ethylene is a basic compound used as a source material in the production of important industrial chemicals including polyethylene, ethylene oxide, vinyl chloride, vinyl acetate, etc., which are extremely important components in the petrochemical supply chain employed in the manufacture of goods such as plastic articles, fibers, paints, coatings, cleaners, solvents, and packaging materials.

[0003] Converting common feeds, such as gas oil, naphtha, liquefied petroleum gas (LPG), and ethane, to ethylene has traditionally been carried out using a thermal conversion process or a catalytic conversion process. A pyrolysis process using steam as a diluent medium is known as steam cracking or steam pyrolysis. In a conventional tubular cracking furnace, the hydrocarbon feed and steam are first mixed and preheated in a residence section and then enter the radiant section (radiant coil) of the furnace. Here, the cracking reaction takes place at a residence time of several seconds to less than 1 second at about 700 - 900 °C.

[0004] As an alternative to tubular furnaces, rotary reactor technology has been successfully employed in steam cracking. For example, U.S. Patent No. 9,494,038 (Bushuev), U.S. Patent No. 9,234,140 (Seppala et al.), and U.S. Patent No. 10,744,480 (Xu and Rosic) describe various rotary reactor configurations. Among these, U.S. Patent No. 9,494,038 and U.S. Patent No. 9,234,140 relate to rotary reactors that include a rotor disk cooperating with a blade cascade disposed between a fixed blade row (stator cascade) essentially disposed on a ring-shaped support and confined within a toroidal gas casing. U.S. Patent No. 9,234,140 also outlines an axial reactor in which rotating and fixed blades are disposed within an essentially tubular casing, whereas U.S. Patent No. 10,744,480 describes a radial flow reactor configuration.

[0005] In all of the above-described rotary devices, a hydrocarbon feed diluted with steam enters a reaction space formed within the reactor and continuously passes through rows of fixed and rotor blades several times before exiting the reactor. As the process fluid propagates through the rows of fixed and rotating blades within the reactor space, it is heated to a temperature at which the feed hydrocarbons decompose to produce lower molecular weight hydrocarbons.

[0006] The inevitable constraints of thermal / thermal cracking are the deposition of carbonaceous deposits, mainly the formation and accumulation of coke. The formation of coke has an adverse effect on the process gas conversion rate and reduces the yield of the target olefins. In the above-described rotary reactor design, heat is directly transferred to the gas stream, and the coke layer formed on the reactor surface causes distortion of the shape of the flow path including the blades. As a result, the gas dynamic efficiency of the reactor decreases, the reactor shaft output decreases, and the temperature at the reactor outlet decreases. The sub-optimal temperature profile reduces the yield of the target pyrolysis products respectively. On the other hand, in the case of a conventional tubular cracking furnace, the coke layer formed on the reactor surface impedes heat transfer through the reactor wall. This may increase the greenhouse gas emissions.

[0007] However, frequent decoking by conventional methods, such as burning a mixture of high-pressure air and steam (up to 900 °C), shortens the life of the cracking equipment. In addition, decoking requires that the production line be held for about 20 - 40 hours. This has a significant adverse impact on the process economy.

[0008] In the case of the above-described rotary reactor design, coke formation is most concentrated within the reactor zone where the reaction temperature exceeds approximately 750 - 850 °C. This is also the zone where the cracking reaction is most concentrated.

[0009] Steam as a diluent medium reduces the cracking reaction rate by reducing the hydrocarbon partial pressure. This improves the selectivity of the target olefins (e.g., ethylene) and reduces the coke deposits on the reactor surface. In known solutions, steam is added to the hydrocarbon feed before it enters the reaction zone. Then, the maximum production capacity is determined by calculating the optimal reaction temperature, feed temperature (preheating), and steam-to-hydrocarbon ratio.

[0010] However, developing an improved method for coke formation in thermal cracking equipment still remains a problem, specifically in terms of optimizing and improving the energy cost efficiency of ethylene production on an industrial scale.

SUMMARY OF THE INVENTION

PROBLEMS TO BE SOLVED BY THE INVENTION

[0011] An object of the present invention is to solve or at least mitigate the problems arising from the limitations and drawbacks of the related art. This object is achieved by a method for reducing coke formation during the thermal or thermochemical conversion of a hydrocarbon raw material, and various embodiments of related equipment.

MEANS FOR SOLVING THE PROBLEMS

[0012] In one aspect, based on what is defined in independent claim 1, a method is provided for reducing coke formation during the thermal or thermochemical conversion of a hydrocarbon raw material in the presence of steam using a rotary reactor.

[0013] In an embodiment, a rotor comprising a plurality of rotor blades arranged in at least one row around a rotor hub mounted on a rotor shaft, and a plurality of fixed vanes arranged adjacent to the at least one row of rotor blades, wherein the rotor and the plurality of fixed vanes are enclosed in a duct formed between at least one inlet and at least one outlet within a casing. A method for reducing coke formation during the thermal or thermochemical conversion of a hydrocarbon raw material in the presence of steam, the method comprising: supplying a predetermined amount of additional steam into a duct region where conditions for thermal or thermochemical conversion to occur in the process fluid are established while a process fluid provided as a mixture of a hydrocarbon feed and dilution steam propagates between at least one inlet and at least one outlet within the duct; The additional steam is supplied into the duct through a perforated and / or porous surface disposed on a selected portion of the duct and / or on a stationary vane. A method for reducing coke formation is provided.

[0014] In addition to or alternatively to this, the supply of additional steam may be effected through at least some of the rotor blades.

[0015] In an embodiment, the method includes supplying a predetermined amount of the additional steam into a process fluid propagating through the duct region where the reaction temperature is equal to or exceeds a value of about 750 degrees Celsius (°C).

[0016] In an embodiment, the method includes supplying a predetermined amount of the additional steam into the duct region corresponding to a predetermined number of the last working stages of the rotary reactor.

[0017] In an embodiment, the method includes supplying a predetermined amount of the additional steam into the duct through a perforated and / or porous surface disposed on a stationary guide vane upstream of the rotor blade and optionally on a stationary diffuser vane downstream of the rotor blade.

[0018] In an embodiment, the method includes supplying a predetermined amount of the additional steam into the duct through a perforated and / or porous surface disposed on a selected portion of the duct facing the process fluid flow.

[0019] In an embodiment, the method includes supplying a predetermined amount of the additional steam into the duct through a perforated and / or porous surface disposed along the duct-defining inner wall of the casing.

[0020] In an embodiment, the method includes supplying a predetermined amount of the additional steam into the duct through a perforated and / or porous surface disposed along the duct-defining wall of the flow shaping device.

[0021] In an embodiment, the method includes directing a predetermined amount of said additional steam towards a perforated and / or porous surface via a predetermined number of distribution channels connected to an external steam source.

[0022] In an embodiment, said perforated and / or porous surface is made of a composite material, metal, metal alloy, ceramics, cermet, or a combination thereof.

[0023] In an embodiment, the method further includes reducing the amount of steam at the reactor inlet.

[0024] In an embodiment, the amount of said additional steam is up to about 30% of the total amount of steam used in a thermal conversion process or a thermochemical conversion process.

[0025] In an embodiment, said additional steam supplied into the duct is adjusted to a temperature lower than the temperature of the process fluid stream in order to cool the components and constituents of the rotary reactor.

[0026] In an embodiment, the thermal conversion or thermochemical conversion of a hydrocarbon feedstock is steam cracking of a hydrocarbon feedstock to produce olefins such as ethylene and propylene.

[0027] In another aspect, there is provided a steam delivery device for a rotary reactor used in the thermal conversion or thermochemical conversion of a hydrocarbon feedstock in the presence of steam, based on that described in independent claim 14.

[0028] In another aspect, there is provided a rotary reactor for thermally converting or thermochemically converting a hydrocarbon-containing feedstock in a gaseous diluent, based on that described in independent claim 15.

[0029] In an embodiment, said rotary reactor includes a steam delivery device according to the previous aspect.

Advantages of the Invention

[0030] The usefulness of the present invention results from various reasons according to each specific embodiment. First, the proposed method enables the highly targeted and efficient suppression of the formation and accumulation of carbonaceous deposits, such as coke and other foulants, on the reactor surface facing the process fluid flow. The area of the reactor where coke formation is most concentrated can be targeted. The method further enables the fine-tuning of the steam-to-hydrocarbon ratio during the conversion process. This provides additional flexibility in adjusting the conversion rate and olefin yield.

[0031] This method is highly energy-efficient. This reduces the amount of diluent medium, such as steam, supplied into the cracking process at the reactor inlet. The reduction of diluent steam at the reactor inlet is proportional particularly to the amount of additional steam supplied into the area prone to coke formation. In practice, this amount can account for up to 30 - 35%. Therefore, the process does not require the input of additional energy to heat the steam diluent. Thus, it is not necessary to provide additional steam separation equipment downstream of the cracking reactor.

[0032] By efficiently suppressing fouling of the reactor surface, the method maintains the gas dynamics characteristics of the reactor at the level required to maintain an optimal temperature profile throughout the reaction space over a significantly long period. This lengthens the time span between decoking treatments. The present invention thus eliminates the need for frequent (every few weeks) decoking of the cracking reactor, thereby minimizing the shutdown period of the system related to decoking. The costs associated with maintenance and repair can be reduced, and the lifespan of the reactor can be extended considerably. Without the presence of a coke layer on the reaction surface, the yield of the desired product can be kept constantly high.

[0033] The expression "a number of" here means any positive integer starting from 1, such as 1, 2, or 3. The expression "a plurality of" here means any positive integer starting from 2, such as 2, 3, or 4. The terms "first" and "second" are used here merely to distinguish one element from another, unless expressly stated otherwise, and do not indicate any particular order or importance.

[0034] In the present disclosure, the working blade or rotating blade of a turbomachinery reactor is mainly referred to by the term "blade", while the stationary blade is mainly referred to by the term "vane".

[0035] The term "gasified" is used to indicate that a substance is converted into a gaseous form by any possible means.

[0036] Various different embodiments of the present invention will become apparent by considering the detailed description and the accompanying drawings.

Brief Description of the Drawings

[0037]

Figure 1

Figure 2

Figure 3

Modes for Carrying Out the Invention

[0038] Disclosed herein are detailed embodiments of the present invention with reference to the accompanying drawings. The same reference numerals are used throughout the drawings to indicate the same members. 100, 100A, 100B, 100C, 100D - Reactor device 1 - Rotor shaft 2, 4 - Fixed vane cascades and related fixed vanes 3 - Rotor blade cascade and related rotor blades 3A - Rotor hub / rotor disk 5 - Flow shaping device 6 - Gas casing 7, 7A - Duct and its vane - less portion respectively 8, 8A, 8B - Inlets 9, 9A, 9B - Outlets 10 - High - temperature area 11 - Perforated and / or porous surface for delivering additional dilution medium into the duct 12, 12A, 12B - Supply and distribution channels for guiding additional dilution medium towards the porous and / or perforated surface, where 12B represents a distribution space provided as an extension of the branch channel 12A. 13 - Driving engine 14 - External housing of the reactor

[0039] The present invention relates to a method for preventing or at least significantly reducing the formation of carbonaceous deposits on the surface of a raw material processing facility where the feed enters the reaction space as a mixture of hydrocarbons and a dilution medium, and the accumulation of carbonaceous deposits, which is used in the thermal conversion and / or chemical conversion of hydrocarbon raw materials. Specifically, the method enables the efficient suppression of fouling and coke formation inside a rotating reactor formed for the thermal / thermochemical treatment of hydrocarbon raw materials. The conversion may include reactions of thermal decomposition or thermochemical decomposition that occur while a mixture of a hydrocarbon feed and a dilution medium propagates through the reaction space.

[0040] The method involves supplying an additional dilution medium (diluent) amount into the duct region of the reaction space such that conditions for thermal conversion or thermochemical conversion are established. These are respectively the region where the operating conditions of the highest severity are achieved and the region where the reaction temperature is the highest. Since the hydrocarbon feed conversion reaction is most concentrated in the high severity / high temperature region, the regions mentioned are specifically prone to fouling through the formation and accumulation of carbonaceous deposits, such as coke. In some cases, the high temperature region is also the region where the degree of feed conversion is the highest.

[0041] The high temperature region is indicated by reference numeral 10 in FIGS. 1B and 2A - 2C. Within region 10, conditions for thermal conversion or thermochemical conversion are established. In an embodiment, such conditions are established when the temperature of the process fluid flow propagating through the reactor reaches a value of at least about 700 - 750 degrees (°C). Depending on the feed, the reaction temperature is from about 700 °C to about 950 °C.

[0042] The term "additional" in this context refers to the amount of dilution medium supplied into 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 the same (having the same material composition).

[0043] It is also conceivable in appropriate cases that the additional diluent is a different form with respect to the material composition from the primary diluent.

[0044] In an embodiment, the disclosed method is employed for use in a process of thermally cracking or steam cracking a hydrocarbon feed in the presence of a gaseous diluent. In an embodiment, the gaseous diluent is (steam). In an embodiment, the steam is used as a dilution medium for the hydrocarbon feed at the reactor inlet and is delivered in a targeted manner into the high temperature area of the reaction space as an additional diluent. The disclosed method can advantageously be employed for the steam cracking of hydrocarbon feeds to produce lower molecular weight products.

[0045] In an embodiment, examples of hydrocarbon feedstocks include naphtha and gas oil, liquefied petroleum gas (LPG) (LPG: propane and butane), and natural gas liquids gas liquids / NGL (ethane, propane, butane). Propane and heavier fractions can also be further utilized. Other feedstocks may be used if appropriate.

[0046] The disclosed method can be carried out in a rotary turbomachinery type reactor 100 formed for the thermal or thermochemical conversion of hydrocarbon feedstocks, comprising a casing having at least one inlet and at least one outlet, a rotor having a plurality of rotor blades arranged in at least one row around a rotor hub mounted on 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 confined within a duct formed between at least one inlet and at least one outlet within the casing.

[0047] Figures 1A, 2A and 2B show rotary reactor apparatuses 100 embodied as 100A, 100B and 100C respectively, formed to employ the disclosed method. Based on the following description, it is further assumed that those skilled in the art can implement this method in other types of rotary reactors, such as the reactor 100D shown in Figure 2C, and those not explicitly shown here.

[0048] In the case of the reactor configurations shown in FIGS. 1A and 3A, the process fluid propagates between the inlet and the outlet along a flow path established based on an essentially helical orbit formed inside an essentially toroidal casing, and the fluid flow continuously passes through a series of fixed guide vanes, rotor blades, and fixed diffuser vanes. This type of device is detailed in U.S. Patent No. 9,494,038 to Bushuev and U.S. Patent No. 9,234,140 to Seppala et al. In the case of the axial reactors shown in FIGS. 2A and 3B, rotating vanes and fixed vanes are enclosed within an essentially tubular casing as described in the disclosure of Seppala et al. FIGS. 2B and 3C show a configuration outlined in U.S. Patent No. 10,744,480 to Xu and Rosic. The method according to the embodiment can be further implemented in a rotating reactor as outlined in U.S. Patent No. 7,232,937 to Bushuev (not shown). The entire content of the above-mentioned documents is considered to be incorporated herein by reference.

[0049] The following description relates to the reactor 100 in all configurations (100A, 100B, 100C, and 100D).

[0050] The reactor 100 includes a rotor system, hereinafter referred to as a rotor, which includes a rotor shaft 1 positioned along a horizontal (longitudinal) axis X-X', and a plurality of rotor blades (also referred to as working blades) arranged to form at least one row around a rotor hub or rotor disk 3A mounted on the rotor shaft. The plurality of rotor blades arranged to form a (blade) row establish a rotor blade assembly or rotor blade cascade 3.

[0051] The rotor is driven by a drive engine. The drive engine may be any one of an electric motor, a gas turbine or a 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 an output converter, a controller, and the like are not described herein. The drive engine is indicated by reference numeral 13 in FIG. 2A.

[0052] The device 100 further includes a fixed (stator) component formed to have a predetermined number of structures (such as the casing 6) that define a reaction space, and a plurality of fixed vanes 2, 4.

[0053] The fixed vanes are each arranged in a row forming a fixed vane cascade adjacent to the rotor blade cascade. A first fixed vane cascade 2 is arranged upstream of the rotor blade cascade 3, and a second fixed vane cascade 4 is arranged downstream of the rotor blade cascade.

[0054] The term "cascade" (blade crown) means an assembly of (working) blades attached around the rotor disk / rotor hub, or (fixed) blades directly or indirectly attached to the inner wall of the casing. For clarity, the fixed blades are referred to as "vanes" in the present disclosure.

[0055] The terms "upstream side" and "downstream side" mean the spatial and / or functional arrangement of a given part or component, here at least one rotor blade row / cascade, as seen in the direction of the fluid flow (direction along the axis X-X', see FIGS. 1A, 2A, 2B) essentially throughout the device.

[0056] A cascade disposed upstream of at least one rotor blade row includes a plurality of fixed guide vanes. The fixed guide vanes can be formed as fixed nozzle guide vanes (NGVs). These vanes form a first fixed vane cascade 2, also called a fixed diffuser vane cascade. A cascade disposed downstream of at least one rotor blade row includes a plurality of fixed diffuser vanes. These vanes form a second fixed vane cascade 4, also called a fixed diffuser cascade. A rotor blade row (cascade) 3 positioned essentially between the fixed blade rows 2 and 4 can be viewed together as a stator-rotor-stator arrangement 2, 3, 4.

[0057] In some forms, the second fixed vane cascade 4 (diffuser) may not be provided.

[0058] The device includes an airtight casing 6 (also called a gas casing or pressure casing). An internal passage 7 is established in the form of a duct or conduit that extends between at least one inlet 8 and at least one outlet 9 within the casing. The inner surface of the casing 6 faces the duct 7. In some forms, the duct 7 is defined by the inner surface of the casing. The shape of the duct / conduit 7 varies depending on the device form.

[0059] In the present disclosure, the gas casing 6 is generally referred to as the device casing. In practice, the device 100 can be further enclosed within a separate external housing. A reactor with an external housing 14 is shown in FIG. 2B.

[0060] While FIG. 1A shows a reactor with two inlets 8A, 8B and two outlets 9A, 9B, FIGS. 2A - 2C show forms with one inlet 8 and one outlet 9. Any other form may be considered where appropriate. The inlets and outlets include associated orifices or ports within the casing 6, and a predetermined number of branch pipes, sleeves, or manifold channels in communication with each said port.

[0061] The casing 6 is formed to substantially completely surround the periphery of a rotor on which a plurality of working blades are integrated, in order to form at least one rotor blade cascade 3 and a plurality of fixed vanes 2, 4 arranged adjacent to the rotor blade cascade.

[0062] In the apparatus 100, the arrangement relationship of the blade rows 2, 3, and 4 in the internal passage 7 inside the casing 6 is such that a vane-less portion 7A (so-called vane-less space) is formed between the outlet from the fixed diffuser vane row 4 arranged on the downstream side of the rotor blade and the inlet to the fixed guide vane row 2 arranged on the upstream side of the rotor blade.

[0063] The reactor 100 is formed to have a predetermined number of basic stages, also called working stages or process stages. In a specific form, each working stage is formed to have a continuous blade row of fixed guide vanes 2, rotor blades 3, and optionally fixed diffuser vanes 4. The reactor can be formed as a single reactor or a multi-stage reactor. A multi-stage form including 2 to 10 rotor blade rows mounted on the rotor shaft is conceivable (see, for example, 100B, 100C, 100D). In such a multi-stage form, the stages can be driven by the same or different (for example, joined) rotor shafts.

[0064] The working stages are shown in FIGS. 1B, 2A - 2C by Roman numerals (i - vii).

[0065] The function of the basic stage is to impart mechanical energy to the process fluid and further convert the mechanical energy into thermal energy. During the energy conversion cycle, the fixed guide vane row 2 arranged on the upstream side of the rotor blade 3 prepares 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 a portion of each rotor blade row 3, the fluid flow can reach supersonic flow conditions.

[0066] The stationary blade row (diffuser 4) arranged on the downstream side of the rotor blade 3 converts the mechanical energy of the fluid into its thermal energy (heat). The fluid medium flow exits the rotor blade 3 and enters the diffuser 4 at supersonic speed. When the flow on the upstream side of the diffuser is supersonic, the kinetic energy of the fluid flow is converted into the internal energy of the fluid through a system of multiple shocks, viscous mixing, and dissipation. The flow dissipates its kinetic energy into the internal energy of the fluid flow propagating through the reactor (along the duct 7), thus adding an amount of thermal energy to the fluid. The increase in the internal energy of the fluid results in an increase in the fluid temperature.

[0067] The fluid flow propagating through the device 100 passes through several working stages continuously, and by each passage, the temperature of the process fluid is raised by a specific value. More precisely, the temperature rise occurs when the process fluid flow exits the rotor blade and passes through the diffuser and the vaneless space. The temperature rise promotes the thermal decomposition or thermochemical decomposition of the feedstock species and its conversion to the desired products. The amount of thermal energy added to the medium is sufficient to initiate a chemical decomposition reaction, specifically a reaction that decomposes the chemical bonds of long carbon-carbon (C-C) chains. Thus, the high molecular weight compounds present in the fluid flow are effectively reduced in size. In the working stages where the temperature and process flow conditions are sufficient for thermal or thermochemical conversion to occur, a series of chemical reactions that initiate the conversion of the feed hydrocarbon to the target product mainly occur within the vaneless portion 7A of the duct.

[0068] In a form without stationary diffuser vanes, the vaneless space is formed on the downstream side of the rotor blade cascade. Such a form may be adopted, for example, for the reactor 100C shown in FIG. 2B (see stages i, iv - vii implemented without the diffuser vanes 4). In such a case, the vaneless portion of the duct acts as an energy converter with respect to its three-dimensional shape and is formed to convert the mechanical energy imparted to the process fluid by the rotor into heat.

[0069] Within reactor 100, the temperature rise can be optimized as desired. The temperature rise achieved in one stage can be from about 10°C to about 120°C. Thus, in any one of 100A - 100D (all provided as multi-stage solution means), the fluid can be heated to about 1000°C in a "one-pass" configuration (considering a 100°C temperature rise per stage in a 10-stage device). Since the residence time spent by the reaction fluid passing through the reactor stage is less than 1 second, for example, about 0.01 - 0.1 seconds, even in the most basic form, high-speed and efficient heating can be achieved.

[0070] In some cases, the reactor may include a so-called inlet stage and optionally an outlet stage. The form of these stages may be different from that of the working stages.

[0071] As the process fluid (a mixture of a hydrocarbon feed and a gaseous diluent, such as steam) propagates between the inlet and the outlet through the working stages, its temperature gradually rises. The thermal conversion process involving the decomposition of the feed hydrocarbon to lower molecular weight products, here thermal cracking, occurs in duct area 10 where the cracking severity is at or at least close to its maximum value. The reaction temperature reaches at least 700 - 750°C within such a duct area. Depending on the feedstock, cracking is most concentrated within the reactor region where the process fluid stream reaches about 700 - 950°C.

[0072] 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, a cracking severity close to the maximum value that results in the highest ethylene yield can be achieved.

[0073] The duct area 10 mentioned is thus called the "high-temperature region". Since region 10 corresponds to the most concentrated reaction, such a region is also a high-turbulence area.

[0074] Considering that the temperature distribution typical of a thermal conversion process, such as steam cracking, which is carried out within the rotary device 100 (any one of 100A to 100D), is approximately 300 to 500 °C at the inlet and approximately 800 to 1300 °C at the outlet, the position of the temperature region 10 in the reactor 100 corresponds to a predetermined number of the last working stages (i.e., a predetermined number of the last working stages close to the reactor outlets 8, 8A, 8B). Typically, within the duct region accommodating 2 to 4 of the outermost stages, the operating conditions, specifically the severity of the temperature, reach a level sufficient for the cracking reaction to occur and proceed close to the maximum level.

[0075] Within the region 10, the reaction rate and optionally the feed conversion rate are the highest. Therefore, the formation of coke and other foulants is most concentrated on the reactor surface facing the duct 7 within the region 10. Inside the region 10, fixed surfaces such as the inner wall of the duct 7 and the fixed vane cascades 2, 4 are particularly prone to being covered with coke formation.

[0076] Note that the span of the high-temperature region 10 along the inside of the reactor 100 / duct 7 is not limited by a specific number of the outermost stages, which depends on the reactor configuration, the total number of (working) stages, the reaction conditions, the process feedstock, and the like.

[0077] Refer to FIG. 1A showing the reactor 100 forming the configuration 100A. Here, the casing 6 has an essentially toroidal shape (a "doughnut" shape) in three-dimensional form. Thereby, a rotor system (1, 3A, 3) with an associated bearing assembly (not shown) can be seen as filling an aperture that defines an opening in the central part of the torus. In its meridional cross-section, the casing 6 is essentially ring-shaped.

[0078] In the reactor 100A, fixed vane cascades 2, 4 are provided as essentially annular assemblies on both sides of the rotor blade cascade 3.

[0079] Reactor 100A further includes a flow shaping device (flow guiding device) 5 disposed inside the gas casing 6. In 100A, the flow shaping device 5 is formed as an internal fixed ring-shaped structure, which is considered to establish an essentially annular duct inside the casing 6. The device 5 is fixed inside the gas casing 6 by appropriate fixtures (not shown). In some forms, the flow shaping device 5 may be provided as an annular, essentially hollow structure, such as a hoop.

[0080] The flow shaping device 5 may be adjacent to the tips of the rotor blades (a gap is formed between them to allow the rotor to rotate unhindered), and when the stator vanes are provided on a bearing block (not shown) that constitutes the bearing system of the rotor, it may also be adjacent to the peripheral portion of the stator vanes. Alternatively, the stator cascade may be integrated on the flow shaping device 5 in a form adjacent to the rotor blades 3. The stator vanes may be mounted on the flow shaping device in this way and / or coupled to the flow shaping device by auxiliary devices such as rings, brackets, and the like (not shown). The above features are discussed in more detail in the patent documents by Bushuev (U.S. Patent No. 9,494,038) and Seppala et al. (U.S. Patent No. 9,234,140) referred to above.

[0081] In reactor 100A, the internal passage is defined by the volume formed between the gas casing 6 (outer "donut") and the internal flow shaping device 5 (inner "donut"). This internal passage (duct 7) formed between the inner surface of the gas casing 6 and the outer surface of the flow shaping device 5 thus adopts an essentially annular shape with an essentially ring-shaped meridional cross-section.

[0082] The location of the high-temperature region 10 inside the reactor 100A is shown in FIG. 1B.

[0083] Figure 1B is a cross-sectional view taken along the A-A and B-B lines shown in Figure 1A. The cross-sectional area along the A-A line is located at the inlet to the fixed guide vane cascade 2, while the cross-sectional area along the B-B line is located at the outlet from the diffuser cascade 4. Cross-sections A-A and B-B can also be regarded as showing events occurring at the inlet to, or the outlet from, the stator-rotor-stator arrangement.

[0084] The inlet to the blade / vane cascade is generally defined by the leading edge of the associated blade / vane, while the outlet from the cascade is defined by the trailing edge of the said blade / vane. The inlet and outlet are defined in the direction of the fluid flow.

[0085] Within the reactor 100A, the process fluid propagates within the duct 7 between the inlet / outlet pairs (8A and 9A, and 8B and 9B respectively). Figure 1B shows the streamlines moving between the first inlet 8A and the first outlet 9A. The streamlines moving between the second inlet 8B and the second outlet 9B are not shown.

[0086] Within the reactor 100A, the raw material-containing process fluid stream flows along a flow path established along an essentially helical trajectory. The process fluid continuously passes through a predetermined number of working stages i-vii defined across the fixed guide vane row 2, the rotor blade row 3, and the fixed diffuser vane row 4. The fluid emerging from the fixed diffuser cascade 4 thus flows "upwards", crosses the vaneless space 7A, and continues towards the fixed guide vane cascade 2 of the subsequent stage.

[0087] As shown in Figure 1B, the reaction is most concentrated within the region along the three final regeneration paths passing through the cascades 2, 3, 4 (stages v-vii). Stages v-vii thus form the high-temperature region 10.

[0088] Figure 2A shows a reactor 100 forming configuration 100B. Reactor 100B is formed as an axial reactor. Axial reactors generally follow the design for axial compressors or turbines. Reactor 100B includes an elongated rotor 1 extending along a horizontal axis X-X'. A plurality of rotor blades are arranged along the rotor hub to form a plurality of continuous rows, thereby forming a rotor blade cascade 3. Rotor 1 is enclosed within a casing 6. The inner surfaces of the casing are each provided with first and second fixed vane cascades 2 and 4. These fixed vane cascades are arranged such that the blades / vanes of the rotor cascade and stator cascades 2, 3, and 4 are alternately positioned longitudinally (along axis X-X') along rotor 1. The fixed vane rows 2, 4 can be arranged on opposite sides of the casing (inner) surface facing the duct. Operating stages i-vii are thus established. Each stage is formed to have a rotor blade cascade 3 and an adjacent stator vane pair 2, 4. A duct portion 7A without blades / vanes is arranged between subsequent stages.

[0089] Casing 6 may be conical in shape or may have an essentially constant cross-section along its entire length (not shown).

[0090] Figure 2B shows a reactor 100 forming configuration 100C. Reactor 100C is formed as a radial turbo machine. The radial turbo machine generally follows the design for a centrifugal compressor or a centrifugal pump. The term "centrifugal" implies that the fluid flow inside the device is in the radial direction, and thus, device 100C is called a "radial flow device". The reactor shown in Figure 2B includes a predetermined number of working stages (i - vii). Each stage is represented as having a fixed guide vane cascade 2, a rotor blade cascade 3, and a fixed diffuser vane cascade 4. The diffuser is arranged within a duct 7 and an essentially U - shaped conduit provided as part of duct 7 and a subsequent vane - less portion 7A. In some configurations, the diffuser vanes 4 may not be provided. In this case, the vane - less U - shaped conduit arranged downstream of the rotor blades may act as an energy converter.

[0091] In configurations 100B and 100C, the high - temperature region 10 starts approximately between stages v and vi and extends through the last stage vii to the outlet 9. The span of region 10 within the duct may vary depending on the reactor configuration, the total number of stages, the process conditions, etc.

[0092] Figure 2C shows 100D, which is any other type of multi - stage rotating reactor device. The multi - stage rotating reactor device can be formed to adopt the method according to the embodiment. In exemplary configuration 100D, the high - temperature region 10 is established in the two last stages (iv and v).

[0093] To suppress the formation and accumulation of carbonaceous deposits, such as coke and other foulants, on the reactor surface in contact with the process fluid flow inside the high - temperature region 10, it is proposed to supply an additional gaseous diluent amount into region 10. Fundamental to the present invention is the observation that by supplying the additional gaseous diluent into duct 7 through perforations and / or pores formed within a selected structure inside the high - temperature region 10, the formation of coke and other foulants can be prevented or at least significantly reduced.

[0094] When a hydrocarbon-containing process fluid (a mixture of a hydrocarbon feed and a gaseous diluent, such as steam) propagates through duct 7, injecting an additional diluent into the process-intensive high-temperature region 10 has been found to be beneficial in suppressing coke formation in the process of thermal conversion or thermochemical conversion of the hydrocarbon raw material.

[0095] The amount of additional gaseous diluent injected into the process can reach 30 - 35% of the total gaseous diluent amount. At the same time, the amount of gaseous diluent at the reactor inlet can be reduced. This enables maintaining the total energy consumption at the same level (because there is no need to heat the additional diluent medium) and avoiding the difficulties associated with the separation of excess steam on the downstream side.

[0096] In an embodiment, the gaseous diluent is (water) steam. Injecting additional steam into the high-temperature region 10 effectively suppresses the formation of coke and other foulants in the steam cracking process employed in the production of light olefins, such as ethylene and propylene.

[0097] The steam supplied as an additional diluent medium into region 10 reduces the hydrocarbon partial pressure, thereby suppressing or reducing the formation of coke deposits.

[0098] The steam as an additional diluent is delivered into the reactor 100 and into region 10 through a selected portion of duct 7 facing the process fluid flow and / or through a predetermined number of fixed structures including fixed vanes 2, 4. In some cases, the additional diluent can be injected through a working / rotating blade. However, for the purposes of the present invention, a fixed structure is preferred.

[0099] The said selected portion of duct 7 includes the surface defining the inner wall of the gas casing 6 (the inner surface of the gas casing), the surface of the flow shaping device 5 defining the duct (see form 100A), and any other surface confining the process fluid flow.

[0100] Delivery of the vapor as an additional diluent into the duct 7 can be carried out through any one of the fixed guide vanes 2, the fixed diffuser vanes 4, the vane-free portion 7A of the duct 7 located downstream of the diffuser vanes 4, or any combination thereof.

[0101] In order to deliver the vapor as an additional diluent into the high-temperature region 10, the selected fixed structure or a part thereof is perforated and / or made porous. The perforated and / or porous surface for delivering the additional diluent medium into the duct is denoted by reference numeral 11 in FIGS. 3A, 3B and 3C.

[0102] The vapor as an additional diluent medium is guided towards the perforated and / or porous surface 11 through a predetermined number of distribution channels 12, 12A arranged in any one of the fixed vanes 2, 4, the casing 6, the flow shaping device 5, or any combination thereof. The gaseous diluent may be supplied into the high-temperature region 10 from the same source as that for supplying, for example, the vapor, which is a diluent medium to be mixed with the hydrocarbon feed at the reactor inlet. A predetermined number of distribution channels 12 may be arranged in the region 10 to receive the gaseous medium from an external diluent medium source (not shown). The channels 12 are preferably arranged to branch at desired locations to form a plurality of branch channels 12A (see FIG. 3C).

[0103] The supply and distribution channels 12, 12A are further expanded to form a distribution space 12B so as to enclose the surface 11 on at least a part of the perforated / porous surface 11 (see FIG. 3C). By enclosing the perforated and / or porous surface 11, the gaseous diluent can be uniformly distributed into the reaction space (i.e., inside the duct 7 and its vane-free portion 7A) through the perforated and / or porous structure (11). The distribution space 12B may be provided as an extended portion of the branch channel 12A.

[0104] Together with distribution channels 12, 12A, 12B and a predetermined number of perforated and / or porous surfaces 11, a steam delivery device for a rotary reactor is formed. In said device, the distribution channels 12, 12A, 12B are formed to deliver steam to the perforated and / or porous surface 11. The surface allows the penetration of steam into the reaction space. The reaction space is defined by the internal space of the reactor, i.e., duct 7. The steam delivery device is preferably mounted inside the high-temperature region 10.

[0105] The diluent supply through the fixed blades 2, 4 is carried out such that the gaseous diluent is supplied into the blade cavity through the branch channel 12A, whereby the diluent exits the blade cavity (and enters the reaction space / duct 7) through a plurality of holes / pores arranged in the blade wall. The perforated fixed blades 2, 4 are shown in FIGS. 3A and 3B (lower images).

[0106] FIGS. 3A - 3C show exemplary locations for supplying additional gaseous diluent into the reactor along the high-temperature region 10. The additional gaseous diluent flows are indicated by arrows in FIGS. 3A (upper image) and 3B (upper image) and 3C.

[0107] All or selected fixed blades inside the region 10 can be modified as follows. Any one of the vertical surfaces of the blade shell, i.e., the pressure side, i.e., the side where the flow enters the blade, and / or the suction side, i.e., the side where the flow separates from the blade, can be made perforated or porous. In some cases, the entire blade shell may be formed of a porous material.

[0108] If a perforated and / or porous surface 11 is provided on the pressurized side of the wing, a diluent boundary level is formed, and thus the concentration of hydrocarbons near the blade wall decreases. Modifying the blade pressurized side to have a perforated and / or porous surface 11 can be done for all or selected stationary guide vanes and / or for all or selected stationary diffuser vanes. On the other hand, if a surface 11 is provided on the suction side, it becomes possible to prevent the return vortex formed by the flow leaving the blade from contacting the blade again. It may be preferable to modify the suction side for all or selected stationary diffuser blades.

[0109] In addition to or instead of this, by modifying the casing 6 and the flow shaping device 5 (if applicable), a perforated and / or porous surface 11 can also be incorporated. Inside the region 10, any surface of the duct 7 that confines the process fluid flow can be modified to include perforations and / or pores. For example, the surface 11 may be disposed within the flow separation region. Here, the process flow swirls after leaving the diffuser blade (see Figure 3C, the circled area 12B).

[0110] Overall, the position of the perforated and / or porous surface 11 is optimized to prevent coke formation. For example, the placement of the surface 11 on the suction side of the diffuser blade (where the flow separates from the blade) is not used in conventional blade cooling.

[0111] The part of the reactor including the perforated and / or porous surface 11 can be made of a composite material, metal, metal alloy, ceramics, cermet, or a combination thereof.

[0112] The formation of deposits on the reactor surface can also be further prevented by controlling the (additional) steam flow rate supplied towards the surface 11 through the distribution channels 12, 12A, 12B.

[0113] In the method, the temperature of the additional steam supplied into region 10 is below the temperature of the process fluid. By adjusting the additional steam diluent stream injected into duct region 10 to a temperature lower than the temperature of the process fluid stream flowing through the duct, the additional steam can be used to cool fixed and non-fixed components, such as the components and parts of a reactor including fixed blades and rotor blades. The additional steam is typically injected at a pressure higher than that of the process fluid stream.

[0114] In one aspect, there is provided a steam delivery device for a rotary reactor 100 used for the thermal conversion or thermochemical conversion of a hydrocarbon feedstock in the presence of steam, the device including distribution channels 12, 12A, 12B and a predetermined number of perforated and / or porous surfaces 11 disposed on fixed vanes 2, 4 and / or on a selected portion of duct 7 defining the reaction space of the rotary reactor. The distribution channels 12, 12A, 12B are formed to deliver steam to the perforated and / or porous surfaces 11, and the surfaces enable the penetration of the steam into the reaction space. The steam delivery device is mounted within a section of the rotary reactor such as to confine the high-temperature region 10 within the reaction space where the conditions for thermal conversion or thermochemical conversion are established. In some cases, elements 11, 12 of the steam delivery device may be incorporated into at least some of the rotor blades 3.

[0115] Optionally with cooling of the components and parts of the reactor, there is provided the use of the steam delivery device in reducing coke formation during the thermal conversion or thermochemical conversion of a hydrocarbon feedstock within rotary reactor 100, the reduction of coke formation and optionally cooling being achieved by delivering a predetermined amount of additional steam into the high-temperature region 10 of the reaction space in the manner described above.

[0116] In one aspect, there is provided a rotary reactor 100 (100A, 100B, 100C, 100D) for thermally or thermochemically converting a hydrocarbon-containing feedstock in a gaseous diluent, the rotary reactor 100 including a casing 6 having at least one inlet 8 and at least one outlet 9, a rotor 1 including a plurality of rotor blades 3 arranged in at least one row around 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 confined within a duct 7 formed between at least one inlet and at least one outlet within the casing. The reactor includes a perforated and / or porous surface 11 disposed on a selected portion of the duct defining structure and / or on the stationary vanes 2, 4 so as to allow an additional gaseous diluent to flow therethrough, and the perforated and / or porous surface is disposed within a high temperature region 10 of the duct where conditions for thermal or thermochemical conversion are established.

[0117] In an embodiment, the perforated and / or porous structured surface is incorporated into a selected stationary vane and / or a selected portion of the duct wall facing the process fluid flow and optionally into at least some of the rotor blades.

[0118] The reactor is configured to thermally assist in the conversion of a feedstock in a fluid diluent medium, specifically to thermally crack or thermochemically crack a hydrocarbon-containing feedstock. The cracking process involves a fluidized hydrocarbon-containing feedstock (i.e., a fluidized organic feedstock material mainly containing carbon and hydrogen). In some embodiments, the process produces olefins, such as ethylene and propylene, by steam cracking a hydrocarbon-containing feedstock.

[0119] In addition to or instead of this, the heat-assisted conversion of the raw material may involve processing organic raw materials. In some forms, the apparatus 100 can be configured to process cellulosic raw materials. In some additional or alternative forms, the apparatus 100 can be configured to process (waste) animal fat-based raw materials and / or (waste) vegetable oil-based raw materials. The processing of the animal fat-based feedstock and vegetable oil-based feedstock may include hydrodeoxygenation (removal of oxygen from oxygen-containing compounds), resulting in the decomposition of the (tri)glyceride structure and mostly linear alkanes. In further additional or alternative forms, the apparatus 100 can be configured to process by-products of the wood pulp industry, such as tall oil, or any derivative thereof.

[0120] Thus, in some cases, the hydrocarbon-containing feedstock may be a gasified pretreated biomass material (a pretreated biomass of cellulose-derived or lignocellulose-derived type supplied into the apparatus in a substantially gaseous form). Other organic raw materials may include pretreated glyceride-based materials, such as (waste or residual) vegetable oil and / or animal fat, or pretreated plastic waste or residues. The pretreatment of the (tri)glyceride-based raw materials may include various different processes as described above, such as pyrolysis or deoxygenation. In the process of recovering pyrolysis oil or gas that can be further used as a raw material for producing new plastics and / or refined into fuel oil (diesel equivalent), various plastic wastes including PVC, PE, PP, PS materials and mixtures thereof can be utilized.

[0121] Thus, the reactor 100 can be formed to perform at least one treatment selected from the group consisting of treating a hydrocarbon raw material preferably containing a medium-weight hydrocarbon fraction and a light-weight hydrocarbon fraction, treating a gasified carbohydrate-containing feedstock, treating a gasified glyceride and / or fatty acid-containing raw material, and treating a gasified cellulosic biomass material.

[0122] When using organic raw materials, the reactor 100 may be further configured for a catalytic process. This is achieved by a predetermined number of catalyst surfaces (not shown) formed by contact of the catalyst coating on the blades or the inner wall with the process fluid. In some cases, the apparatus may include a predetermined number of catalyst modules defined by a ceramic or metal substrate, or a support carrier, optionally having an active (catalytic) coating realized as a monolithic honeycomb structure.

[0123] As will be apparent to those skilled in the art, with the development of technology, the basic idea of the present invention can be implemented in various ways. The present invention and its embodiments can vary generally within the scope of the appended claims.

Claims

1. A reactor (100) having a rotor (1) with a plurality of rotor blades (3) arranged in at least one row around a rotor hub mounted on a rotor shaft, and a plurality of stationary vanes (2, 4) arranged adjacent to said at least one row of rotor blades, said rotor and said plurality of stationary vanes being enclosed in a duct (7) formed between at least one inlet (8) and at least one outlet (9) within a casing (6), for reducing coke formation during thermally converting or thermochemically converting a hydrocarbon feedstock in the presence of steam, the method comprising: supplying a predetermined amount of additional steam into a duct region (10) in which conditions are established for thermal conversion or thermochemical conversion to occur in the process fluid while the process fluid, provided as a mixture of a hydrocarbon feed and dilution steam, propagates between at least one inlet and at least one outlet within said duct (7); wherein said additional steam is supplied into said duct through a perforated and / or porous surface (11) disposed on a selected portion of said duct and / or on the stationary vanes (2, 4); A method for reducing coke formation.

2. The method of claim 1, comprising supplying a predetermined amount of said additional steam into the process fluid propagating through said duct region (10) where the reaction temperature is equal to or exceeds a value of about 750 degrees Celsius (°C).

3. The method according to claim 1 or 2, comprising supplying a predetermined amount of said additional steam into said duct region (10) corresponding to a predetermined number of final operating stages of said rotary reactor.

4. The method according to any one of claims 1 to 3, wherein a predetermined amount of said additional steam is supplied into said duct through a perforated and / or porous surface (11) disposed on a stationary guide vane (2) upstream of said rotor blade (3) and optionally also on a stationary diffuser vane (4) downstream of said rotor blade.

5. The method according to any one of claims 1 to 4, wherein a predetermined amount of said additional steam is supplied into said duct through a perforated and / or porous surface (11) disposed on a selected portion of said duct facing the process fluid flow.

6. The method according to any one of claims 1 to 5, wherein a predetermined amount of said additional steam is supplied into said duct through a perforated and / or porous surface (11) arranged along the inner wall defining the duct of said casing (6).

7. The method according to any one of claims 1 to 6, wherein a predetermined amount of said additional steam is supplied into said duct through a perforated and / or porous surface (11) arranged along the wall defining the duct of said flow forming device (5).

8. The method according to any one of claims 1 to 7, wherein a predetermined amount of said additional steam is directed towards a perforated and / or porous surface (11) via a predetermined number of distribution channels (12, 12A, 12B) connected to a steam source.

9. The method according to any one of claims 1 to 8, wherein said perforated and / or porous surface consists of a composite material, metal, metal alloy, ceramics, cermet, or a combination thereof.

10. The method according to any one of claims 1 to 9, further comprising reducing the amount of steam at said reactor inlet (8, 8A, 8B).

11. The method according to any one of claims 1 to 10, wherein the amount of said additional steam is at most approximately 30% of the total amount of steam used in a thermal conversion process or a thermochemical conversion process.

12. The method according to any one of claims 1 to 11, wherein said additional steam supplied into said duct is adjusted to a temperature lower than the temperature of said process fluid stream in order to cool the components and constituents of said rotary reactor.

13. The method according to any one of claims 1 to 12, wherein the thermal conversion or thermochemical conversion of a hydrocarbon feedstock is steam cracking of a hydrocarbon feedstock to produce olefins, such as ethylene and propylene.

14. A steam delivery device for a rotary reactor (100) used in the thermal conversion or thermochemical conversion of a hydrocarbon feedstock in the presence of steam, said device comprising: distribution channels (12, 12A, 12B); a predetermined number of perforated and / or porous surfaces (11) arranged on a selected portion of a duct (7) defining the reaction space of said rotary reactor and / or on a predetermined number of fixed vanes (2, 4) of said rotary reactor; and The distribution channels (12, 12A, 12B) are formed to deliver vapor to the perforated and / or porous surface (11), and the surface enables the penetration of the vapor into the reaction space. The apparatus is mounted within a section of the rotary reactor that confines a region (10) of the reaction space where conditions for thermal or thermochemical conversion are established. Vapor delivery device. **Claim 15** A rotary reactor (100) for thermally or thermochemically converting a hydrocarbon-containing feedstock in a gaseous diluent, a casing (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 around a rotor hub mounted on a rotor shaft; a plurality of stationary vanes (2, 4) arranged adjacent to the at least one row of rotor blades; comprising wherein the rotor and the plurality of stationary vanes are confined within a duct (7) formed between at least one inlet and at least one outlet within the casing; the reactor includes a perforated and / or porous surface (11) disposed on a selected portion of the duct and / or on the stationary vanes (2, 4) so as to permit the flow-through of an additional gaseous diluent, and the perforated and / or porous surface is disposed within a duct region (10) where conditions for thermal or thermochemical conversion are established; rotary reactor (100). **Claim 16** The rotary reactor according to claim 15, wherein the perforated and / or porous surface (11) is made of a composite material, metal, metal alloy, ceramics, cermet, or a combination thereof. **Claim 17** A rotary reactor (100) for thermally or thermochemically converting a hydrocarbon feedstock in the presence of vapor, the rotary reactor (100) comprising the vapor delivery device according to claim 14.

Images