Reactor for electrified steam cracking

Abstract

The present application relates to a reactor housing (10) for the production of olefins from a feed reactive mixture consisting of steam and hydrocarbons by steam cracking, said reactor housing (10) comprising at least one reaction flow duct (20) formed within said reactor housing (10), at least one structured ceramic bed (30) having a plurality of hollow flow channels (32), at least one electric resistance heating element (40) for heating the reactive mixture flow to a predetermined reaction temperature and a coating (31) provided on the surface in contact with the reactive mixture flow. The reactor housing (10) is characterized in that said electric resistance heating element (40) is arranged within at least some of said hollow flow channels (32) and that a flow passage (323) still exists within said hollow flow channels (32).

Description

Technical Field

[0001] This application relates to a reactor shell for steam cracking to produce olefins, wherein a feed reaction mixture of steam and hydrocarbons flows through the reactor shell for steam cracking to produce olefins, and particularly to a reactor shell with a coated structured ceramic bed having resistance heating elements. This application also relates to a method for electrically heating a reactive gas mixture to induce a reaction. Background Technology

[0002] Ethylene is the most widely used chemical raw material, primarily produced industrially through non-catalytic gas-phase free radical reactions. The demand for ethylene, a structural unit in the so-called "ethylene chain" with styrene-related polymers such as polyethylene and polyvinyl chloride as final products, is continuously increasing, currently reaching 200 million tons per year. As non-catalytic steam cracking is expected to be the most important process for supplying olefins in the coming decades, much work is dedicated to its further improvement and decarbonization.

[0003] The most important pathway for producing ethylene and propylene is the steam cracking of naphtha, ethane, propane, gasoline, and liquefied petroleum gas. Steam crackers are the most important reaction units in the petrochemical industry, providing feedstock for a variety of chemical processes. Steam cracking is the most energy-intensive thermochemical process, currently requiring approximately 15% of primary energy for the chemical industry. This process emits approximately 300 million tons of carbon dioxide, equivalent to the annual CO2 emissions of Italy, the world's eighth-largest economy.

[0004] More than 90% of CO2 emissions are related to heat generated through fuel combustion, which needs to be compensated for the endothermic nature of the reaction. In fact, energy costs account for more than 70% of operating costs. This energy is provided through fuel combustion, which includes burning fresh hydrocarbons and secondary byproducts of the process.

[0005] Steam cracking takes place inside the furnace and can be divided into two distinct sections. In the upper part of the furnace, the feed, hydrocarbons, and steam are preheated using the heat capacity of the hot flue gas. In the bottom (radiant section), the reaction mixture is preheated at a temperature of 500°C to 700°C (cross-point temperature), and the feed reacts in the cracking / reactor coil located within the combustion chamber.

[0006] Only 40-50% of the energy generated by the combustor in the combustion chamber is absorbed and utilized by the reaction. The remaining heat is carried by the flue gas and used for preheating the feed in the convection section. Through improvements and extensive heat recovery, an overall energy efficiency of over 90% is achieved.

[0007] High reaction endothermic rate, high reaction temperature (750℃-900℃), and short residence time (less than 1s) require a heat flux of over 30kWm on the outer surface of the reactor coil. -2 .

[0008] Therefore, there is no uniform radial temperature distribution within the reactor coil, which increases the formation of coke on the inner wall of the radiant tubes. These deposits create additional resistance to heat transfer. In industry, this variable heat transfer resistance requires regulation of combustion that affects the external (interface radiant coil-burner) surface temperature. This alters the temperature gradient across the coil wall, thereby changing the driving force of heat transfer.

[0009] The coke is gasified into CO and CO2 using air and / or steam, and the metal pyrolysis furnace coils are periodically cleaned at the highest working surface temperature (approximately 1150°C). These decoking procedures require production shutdowns, thus necessitating costly daily operations.

[0010] Coatings designed on the inner surface of metal coils can create barriers to coke deposition (barrier coatings) or kinetically minimize its formation (catalytically active coatings), enhancing coke gasification and extending reactor coil operation before regeneration is required. A comprehensive review of coking and anti-coking technologies can also be found in the article "Current Status of Coking Research in Steam Cracking Processes: Anti-coking Surface Technologies" by Symoens S. et al., published in *Industrial and Engineering Chemical Research*, 2018, 571, 16117-16136.

[0011] The mismatch between the coefficients of thermal expansion and the low chemical affinity between the ceramic coating and the metal surface of the reactor coil (such as an alloy containing Ti, NiCrNb) strongly affect the stability and industrial applicability of these coatings.

[0012] Ceramic coils can improve furnace operating temperature, efficiency, and product selectivity. They also minimize coke deposition and provide sufficient surface area for coating deposition. However, the mechanical properties of ceramic reactor coils make their application in cracking furnaces less than ideal.

[0013] For these reasons, improvements to pyrolysis furnaces mainly involve modifications to the metal coils, including: coil cross-sectional geometry, coil 3D configuration, and internal structured packing. In addition, metals that form surface-stable oxides, such as chromates or alumina, have been developed due to their excellent high-temperature resistance and anti-coking properties.

[0014] EP3574991A1 discloses a reactor system for steam reforming heated by an electrically conductive structured catalyst (e.g., a FeCrAl structured catalyst). Similar configurations without catalytically active materials can also be used for steam cracking, as described in WO 2021 / 094346A1. This system includes a pressure reactor shell, an internal insulation layer, and at least two electrical contacts that supply power to a macroscopic structure of a conductive material capable of supporting a ceramic coating. US201400060014 also discloses an electrically heated catalyst involving the energization of a macroscopic metal supporting the catalyst. Further details regarding the use of structured metals in high-temperature reactions can also be found in the article "FeCrAl as a Catalyst Support" by Pauletto G. et al., published in Chemical Reviews 2020, 120, 15, 7516–7550.

[0015] Even though the electrification of the macroscopic conductive structure / support has brought improvements to the reactor design, it is still challenging when applied to temperatures above 700°C and heat fluxes greater than 10 kWm. -2 In highly endothermic processes, these configurations present significant technical challenges and high industrialization costs. These issues primarily relate to the electrification of macroscopic conductive structures, complicating the design of power supply contact rails and related control systems. Industrializing heating elements and process heaters using macroscopic conductive materials for applications above 800°C is currently infeasible and complex due to uneven heat generation. Furthermore, the endothermic nature of steam cracking reactions results in surface loads far exceeding those of conventional gas flow heaters that only exchange specific heat.

[0016] In contrast, US1727584, US5400432, and US9867232B2 disclose a heating element design comprising a ceramic material with a coaxial electric heating wire, which can be used as a gas heater to heat fluids to 1100°C. Due to the low lifespan and harmful carbon formation of uncoated resistance heating elements, this device cannot be used for steam cracking. Furthermore, the resulting blockage due to localized overheating of the channel is further reduced.

[0017] A recent patent application, EP20170265.1, discloses a reactor with an electrically heated structured ceramic catalyst for the production of syngas, hydrogen, or carbon dioxide after a catalytic reaction. The structured ceramic catalyst reaches a temperature of 1300°C. The surface temperature and potential localized hot spots of the resistance heating element are controlled and minimized through the endothermic properties of the reaction, which acts as an energy sink. Therefore, the lifetime of the assembly is maximized. Summary of the Invention

[0018] In view of the above-mentioned technical problems encountered in the prior art, one objective of this application is to simplify and enhance the production of olefins by steam cracking while minimizing coking, pressure drop, carbon dioxide emissions, and improving reaction temperature and product selectivity.

[0019] Another objective of this application is to provide a reactor for producing olefins via steam cracking, which has lower capital and operating costs and minimal downtime.

[0020] To achieve the foregoing objectives, or those disclosed or deducted from the detailed description, this application relates to a reactor shell for producing olefins from a feed reactive mixture stream consisting of steam and hydrocarbons via steam cracking, comprising:

[0021] At least one reaction flow conduit (20) is formed within the reactor shell (10), substantially having at least one reaction flow inlet (21) for the feed of the reactive mixture, a product flow outlet (25) for the olefin product flow to exit the reactor shell (10), and at least one reaction section (23) disposed between the reaction flow inlet (21) and the product flow outlet (25).

[0022] Insulating filler (11) at least partially surrounds the reaction flow conduit (20).

[0023] At least one structured ceramic bed (30) is housed in the reaction section (23) and has a plurality of hollow channels (32) configured to allow the reactive mixture to flow through them.

[0024] At least one resistance heating element (40), including a meandering section (41), is arranged inside at least some of the hollow flow channels (32), connected to at least two electrical feeds (51), and powered by a power supply (50) configured to heat the reactive mixture stream to a temperature that initiates a non-catalytic gas-phase radical reaction involving vapor cracking.

[0025] The coating (31) is selected from a barrier coating (311) or a catalytically active coating (312) disposed on a surface in contact with the reactive mixture flow, thereby minimizing coke deposition.

[0026] In a possible embodiment of the reactor shell, the resistance heating element (40) is inserted from the inlet (321) of the first hollow channel (32), exits from the outlet (322) of the opposite side of the first hollow channel (32), enters the second hollow channel (32), exits, and continues to advance in the remaining hollow channels (32) of the structured ceramic bed (30).

[0027] In another possible embodiment of the reactor shell, the resistance heating element is a resistance wire or resistance strip.

[0028] In another possible embodiment of the reactor shell, the resistance heating element, the electrical feed, and the power source are configured to heat the reactive mixture stream to a temperature of 1200°C.

[0029] In another possible embodiment of the reactor shell, the structured ceramic bed is a combination of multiple ceramic sub-units arranged in a single piece or in a parallel manner to form multiple flow channels.

[0030] In another possible embodiment of the reactor shell, the reaction flow conduit further includes a distribution section and a collection section. The distribution section is formed in an extension of the reaction flow inlet for distributing the reactive mixture flow into the reaction section, and the collection section is formed in an extension of the reaction section for collecting the product flow and transferring the product flow toward the product flow outlet.

[0031] In another possible embodiment of the reactor shell, two reaction sections are provided, which are configured to be aligned in the same direction, wherein a diversion section is provided between the insulating packing to divert all product streams toward the product stream outlet.

[0032] In another possible embodiment of the reactor shell, the material of the structured ceramic bed is selected from SiO2, Al2O3, Y2O3, WO3, ZrO2, TiO2, MgO, CaO, CeO2 and mixtures thereof.

[0033] In another possible embodiment of the reactor shell, the coating material comprises elements from groups IIA, IIIB, IVB, VIIB, IIIA, and IVA of the periodic table.

[0034] In another possible embodiment of the reactor shell, the coating is applied to the surface of the hollow flow channel facing the resistance heating element.

[0035] In another possible embodiment of the reactor shell, the coating is applied to the surface of the resistance heating element facing the structured ceramic bed.

[0036] In another possible embodiment of the reactor shell, the coating is a barrier coating that prevents the reactive mixture flow from contacting the structured ceramic bed and / or the resistance heating element.

[0037] In another possible embodiment of the reactor shell, the coating is a catalytically active coating that enables the gasification of coke generated thermally during the steam cracking gas-phase free radical reaction.

[0038] In another possible embodiment of the reactor shell, the hydrocarbons in the feed reactive mixture stream are selected from naphtha, ethane, propane, gasoline, and liquefied petroleum gas.

[0039] In another possible embodiment of the reactor shell, the resistance heating element is made of FeCrAl alloy or has a resistivity of 1×10⁻⁶. -7 Ωm to 1×10 -5 Other materials with Ωm.

[0040] This application also relates to a method for producing olefins from a feed reactive mixture stream consisting of steam and hydrocarbons in a reactor shell via steam cracking. The reactor shell includes at least one reaction flow conduit, insulating packing, at least one structured ceramic bed, at least one resistance heating element, and a coating. The at least one reaction flow conduit generally has a reaction flow inlet, a product flow outlet, and a reaction section disposed between the reaction flow inlet and the product flow outlet. The insulating packing at least partially surrounds the reaction flow conduit. The at least one structured ceramic bed is housed in the reaction section and has a plurality of hollow channels configured to allow the reactive mixture stream to pass through. The at least one resistance heating element is powered by at least two electrical feeds connected to a power source and configured to heat the reactive mixture stream to a predetermined temperature for initiating a non-catalytic gas-phase radical reaction that triggers steam cracking. The coating is disposed on a surface in contact with the reactive mixture stream. The method includes the following steps:

[0041] The resistance heating element is arranged inside at least some of the hollow flow channels in such a way that the flow channel remains within the hollow flow channel.

[0042] By energizing the resistance heating element, the reactive mixture is heated to 1200°C.

[0043] A reactive mixture at a temperature of 400°C to 700°C and a pressure of 1 bar to 10 bar is fed into the reactor shell (10) through the reaction inlet.

[0044] The reactive mixture flow is made to contact the resistance heating element and the structured ceramic bed through the hollow flow channel.

[0045] The olefin product stream exits from the product stream outlet.

[0046] In a possible application of the method, the reactive mixture stream undergoes a non-catalytic gas-phase radical reaction involving steam cracking in the reaction section.

[0047] Figure Labels

[0048] 10 Reactor Shell

[0049] 11 Insulating Filler

[0050] 111 Diversion Section

[0051] 20 reaction flow pipes

[0052] 21 Reaction Inlet

[0053] 22 allocation segments

[0054] 23 reaction sections

[0055] 24 collection segments

[0056] 241 sedimentation chamber

[0057] 25 Product Flow Export

[0058] 30 Structured Ceramic Beds

[0059] 31 Coating

[0060] 311 Barrier Coating

[0061] 312 Catalytic Active Coating

[0062] 32 Hollow Flow Channel

[0063] 321 Flow Channel Inlet

[0064] 322 flow channel outlet

[0065] 323 flow channel

[0066] 40 resistance heating element

[0067] 41 winding sections

[0068] 50 power supply

[0069] 51 power supply

[0070] W: Width Attached Figure Description

[0071] Figure 1 The longitudinal section of the reactor shell is shown.

[0072] Figure 2 A longitudinal section of another embodiment of the reactor shell is shown.

[0073] Figure 3 A cross-section of the reactor shell is shown.

[0074] Figure 4 A cross-section of another embodiment of the reactor shell is shown.

[0075] Figure 5A representative view of the coating on the structured ceramic bed is shown.

[0076] Figure 6 A representative view of the coating on the structured ceramic bed and resistance heating element is shown.

[0077] Figure 7 The longitudinal section of the structured ceramic bed used in the reactor shell is shown. Detailed Implementation

[0078] Preferred embodiments of this application will now be described in more detail by way of non-limiting examples with reference to the accompanying drawings.

[0079] exist Figure 1 The image shows the shell (10) of a reactor for producing olefins from a feed reaction stream (i.e., a reactive mixture stream) via steam cracking. The reactor shell (10), with insulating packing (11), mainly comprises a reaction flow conduit (20) and a structured ceramic bed (30). The reaction flow conduit (20) is formed within the reactor shell (10) and surrounded by the insulating packing (11). The structured ceramic bed (30) is disposed within the reaction flow conduit (20) to enable non-catalytic steam cracking within the reactor shell (10). The structured ceramic bed (30) has resistance heating elements (40) powered by at least two electrical feeds (51) that pass through the reactor shell (10) in an insulated manner. The electrical feeds (51) are connected to a power source (50), which is located outside the reactor shell (10) and configured to heat the gas stream (30) to the desired temperature for the desired reaction to occur. Due to this arrangement, the reactive mixture flows through the reaction flow pipe (20) and exits from the pipe after the reaction. Structural and process details will be described in detail below.

[0080] The reaction flow conduit (20) comprises, in downstream order, at least one reaction flow inlet (21), a distribution section (22), a reaction section (23), a collection section (24), and a product flow outlet (25). In a preferred embodiment, the distribution section (22) is provided in the form of a truncated cone. However, in other embodiments, the distribution section (22) may have a truncated cone or cylindrical shape or any other 3D geometry. The reaction section (23) comprises a structured ceramic bed (30) with an equivalent diameter of 5 cm to 300 cm. In one embodiment, two reaction sections (23) are provided, and correspondingly, the reactor shell (10) has two reaction flow inlets (21). In this embodiment, the reaction sections (23) are arranged aligned in the same direction such that the collection section (24) is located between the reaction sections (23). The product flow outlet (25) is placed perpendicular to the reaction section (23) in the extension of the collection section (24). Insulating packing (11) is provided in the collection section (24) to form a diversion section (111). The diversion section (111) is configured to divert all generated olefins (i.e., the product stream) toward the product outlet stream (25). Specifically, the diversion section (111) has a width (W) of 0.5 to 1.0 of the width of the structured ceramic bed (30) to divert the product stream toward the product outlet stream (25) in such a way that the product stream does not remain in the collection section (24). In an embodiment having a reaction section (23), the product outlet stream (25) may be positioned perpendicular to the reaction section (23) or in the same direction as the collection section (24).

[0081] Reference Figure 1 , Figure 2 and Figure 4 A cavity-shaped deposition chamber (241) is provided in the extension of the reaction section (23), which is located at a different level from the product outlet (25). In embodiments where the reactor shell (10) has a reaction section (23), the deposition chamber (241) is located at a level lower than the product outlet (25). Figure 2 In the embodiment shown, the diversion section (111) defines two deposition chambers (241) facing the reaction section (23).

[0082] A structured ceramic bed (30) is positioned within the reaction section (23). (Refer to...) Figure 1 , Figure 2 and Figure 3The structured ceramic bed (30) has multiple hollow channels (32) through which reactive mixtures flow. The structured ceramic bed (30) can be formed as a combination of multiple ceramic subunits having hollow channels (32), such as granular, tubular, monolithic or other ceramic shapes, arranged in a side-by-side and having an axial length of less than 300 cm. Thus, the shape and arrangement of the hollow channels (32) are defined by the structure of the structured ceramic bed (30). The structured ceramic bed (30) is manufactured using non-limiting examples of ceramic materials, including SiO2, Al2O3, Y2O3, WO3, ZrO2, TiO2, MgO, CaO, CeO2 and mixtures thereof.

[0083] Reference Figure 5 A coating (31) is provided on the surface of the hollow flow channel (32) facing the resistance heating element (40). The coating (31) can be a barrier coating (311) or a catalytically active coating (312). In a preferred embodiment, the barrier coating (311) and / or the catalytically active coating (312) have a thickness of less than 500 μm. The materials of the barrier coating (311) and the catalytically active coating (312) can contain elements from groups IIA, IIIB, IVB, VIIB, IIIA, and IVA of the periodic table. Due to the physicochemical properties of the structured ceramic bed (30), the deposition, adhesion, and stabilization of the coating (31) are more advantageous than any other structure supported on a metal structure. Reference Figure 6 In an alternative embodiment, the coating (31) is also applied to the surface of the resistance heating element (40) facing the structured ceramic bed (30).

[0084] like Figure 3 and Figure 7 As shown, the resistance heating element (40) of this application is disposed within a hollow flow channel (32), thereby providing contact between the resistance heating element (40) and the reactive mixture flow. Specifically, in a preferred embodiment of this application, the resistance heating element (40) meanders through some or all of the hollow flow channels (32). In this specification, the term "meanders" means that the resistance heating element is inserted from the flow channel inlet (321) of the first hollow flow channel (32) and exits from its opposite side (flow channel outlet (322)). The resistance heating element (40) then enters the second hollow flow channel (32), exits, and continues to advance in the remaining hollow flow channels (32), as... Figure 3 and 7 As shown.

[0085] The physical proximity of the resistance heating element (40) to the structured ceramic bed (30), its high viewing angle coefficient, and its direct contact with the reactive mixture flow enhance heat transfer through radiation, convection, and conduction. Accordingly, the combination of the structured ceramic bed (30) and the resistance heating element (40) must be arranged in a manner that minimizes pressure drop while maintaining high heat and mass transfer. For example, the resistance heating element (40) is preferably sized to leave sufficient flow passage (323) within the hollow flow channel (32) once installed, so as to minimize the impact on the flow of the reactive mixture while maintaining proximity to the structured ceramic bed (30), i.e., close to the inner wall of the hollow flow channel (32).

[0086] On the other hand, the deployment and installation of the resistance heating element (40) within the hollow flow channel (32) is applied by the selected type of structured ceramic bed (30).

[0087] For example, a structured ceramic bed (30) is an assembly of tubes having longitudinal channels arranged side-by-side, defining a grid-like cross-section. Due to the side-by-side arrangement of these sub-units, the flow of the reactive mixture is confined within the hollow channels (32) where the reactive mixture is heated and reacted. If the sub-units are arranged in a non-side-side manner, the reactive mixture can flow through the bypass area left between adjacent sub-units. Since the bypass area is outside the hollow channels (32), the reactive mixture flow does not contact the resistance heating element (40). Therefore, by fixing the temperature of the resistance heating element (40), the temperature of the reactive mixture flow will decrease, resulting in a decrease in conversion and selectivity. Therefore, if an integral structured ceramic bed (30) is used within the reactor shell (10), such as Figure 3 and Figure 7 As shown, the resistance heating element (40) is placed longitudinally within the hollow flow channel (32) and extends coaxially in the flow direction of the reactive mixture. The meandering section (41) of the resistance heating element (40) remains outside the hollow flow channel (32). Therefore, when the resistance heating element (40) is installed in the structured ceramic bed (30), preferably a resistance wire or resistance strip, the resistance heating element (40) is inserted from the flow channel inlet (321) of the first hollow flow channel and exits from its opposite side (flow channel outlet (322)). Subsequently, the resistance heating element (40) enters the second hollow flow channel (32), exits, and continues in the remaining hollow flow channel (32), as... Figure 3 and Figure 7 As shown.

[0088] If a foam-type (i.e., open-cell type) structured ceramic bed (30) is selected, the resistance heating element (40) can extend in all directions, similar to a hollow flow channel (32) defined by the foam structure. Specifically, the resistance heating element (40) passes through the opening, defining a hollow flow channel (32) of the structured ceramic bed (30) from its inlet to its outlet opening, creating a heating channel along the placement of the resistance heating element (40). In this case, the reactive mixture flow flows in all directions due to the omnidirectional open structure of the open-cell foam of the structured ceramic bed (30). The meandering of the resistance heating element (40) is accomplished in a manner similar to the previously described embodiment, i.e., meandering along the hollow flow channel (32) in the open-cell structure of the structured ceramic bed (30) to form a heating channel in which the reactive mixture flow is heated and reacted.

[0089] Preferably, the resistance heating element (40) is a resistance wire. The resistance wire has a polarity of less than 0.30 cm. 2 The cross surface area allows it to easily meander and reside in the hollow channels (32) of the ceramic bed (30), which is preferably formed as a parallel assembly of sub-units.

[0090] However, in alternative embodiments, strip or rod-shaped resistance heating elements (40) can also be used. By changing the geometry of the resistance heating element (40), the heat exchange surface area can be increased by up to 30%, directly affecting the surface load (heat flux density of the outer surface) of the resistance heating element (40). Furthermore, the geometry of the resistance heating element (40) alters fluid dynamics, increasing the Reynolds number and thus enhancing transport phenomena. Thus, because the geometry of the resistance heating element (40) changes the flow pattern that causes localized eddies and / or swirls, operation can be performed outside the laminar flow region of a conventional structured ceramic bed (30).

[0091] The material of the resistance heating element (40) is FeCrAl alloy or has a resistivity of 1×10⁻⁶. -7 Ωm to 1×10 -5 Other materials with Ωm.

[0092] In view of the above-described structural properties of this application, the progress of the reaction process is described in detail below.

[0093] First, the gaseous reactive mixture stream enters the distribution section (22) through the reaction stream inlet (21). The temperature range of the reactive mixture stream is 400°C to 700°C, and the pressure range is 1 bar to 10 bar. The reactive mixture stream consists of steam and one or more hydrocarbons selected from naphtha, ethane, propane, gasoline, and liquefied petroleum gas. Subsequently, the supplied reactive mixture stream moves to a structured ceramic bed (30) disposed in the reaction section (23).

[0094] The distribution section (22) and its associated geometry ensure that the reactive mixture flow is uniformly distributed across the cross-section of the reaction section (23) before entering the structured ceramic bed (30) with associated resistance heating elements (40). The geometry of the distribution section (22) avoids the presence of localized eddies and / or dead volumes, thereby ensuring a narrow residence time distribution within the reactor shell (10). Thus, the possibility of carbon formation and / or the generation of undesirable products due to over-cracking is minimized compared to any other disclosed configuration.

[0095] The distribution section (22) needs to uniformly distribute the reaction mixture vapor along the cross-section of the reaction flow pipe (20) near the flow channel inlet (32). This ensures that each flow channel (323) draws in the same amount of reactive mixture flow. This will ensure that the hydrodynamic state, heat and mass transfer, energy demand, and temperature distribution remain constant in each flow channel (323) of the structured ceramic bed (30). The distribution section (22), located within the reaction flow pipe (20), compensates for low Reynolds number and radial velocity distribution, which characterizes the flow of the reactive mixture within the reactor shell supporting the structured bed. A lack of optimized distribution section (22) can lead to preferential flow paths, resulting in high-temperature and low-temperature zones within the structured ceramic bed (30), reduced lifespan of the resistance heating element (40), and wide residence time distribution.

[0096] The reactive mixture stream continuously exchanges heat and reacts through the structured ceramic bed (30). In the structured ceramic bed (30), the reactive mixture stream of steam and hydrocarbons reaches a sufficient temperature to thermally activate the non-catalytic gas-phase radical reaction of steam cracking.

[0097] The structured ceramic bed (30) is configured to prevent any flow bypass. In other words, the entire reactive mixture flowing through the reaction section (23) enters the hollow channel (32) and comes into contact with the resistance heating element (40).

[0098] The structured ceramic bed (30) carries the resistance heating element (40) and serves as a physical boundary and refractory sleeve to prevent electrical short circuits.

[0099] The resistance heating element (40) generates heat that is transferred to the structured ceramic bed (30) and the reactive mixture flow. The reactive mixture flow is in direct contact with the electric heating element (40) and the structured ceramic bed (30). This avoids resistance and limitation to heat transfer and minimizes the surface temperature of the electric heating element (40).

[0100] The temperature difference between the resistance heating element (40) and the reactive mixture flow is minimized as the mixture flow passes through the hollow channel (32), which is a small annular gap formed by the resistance heating element (40) and the structured ceramic bed (30). This directly affects the radial temperature gradient, thereby influencing the carbide formation potential and steam cracking selectivity.

[0101] The resistance heating element (40) exchanges heat primarily with the structured ceramic bed (30) through radiation, which benefits from a maximized viewing factor. The reactive mixture flow exchanges heat primarily with the resistance heating element (40) and the structured ceramic bed (30) through convection.

[0102] Unlike conventional reactor coils used for steam cracking, the structured ceramic bed (30) and resistance heating element (40) do not contain components such as Ni that catalytically activate coke formation. Both the structured ceramic bed (30) and resistance heating element (40) provide surfaces suitable for conventional coating processes, compared to any disclosed apparatus for steam cracking. Furthermore, issues concerning insufficient specific surface area, poor chemical affinity, and mismatch in the coefficients of thermal expansion between the carrier and coating materials are avoided. This is particularly relevant when comparing the designs disclosed herein with configurations where ceramic coatings are supported on metallic structures.

[0103] In one of the disclosed embodiments, a barrier coating (311) disposed on the surface of the structured ceramic bed (30) prevents the reactive mixture flow from coming into direct contact with potential acid sites (i.e. Lewis acid sites of Al2O3) that may partially cause coke formation.

[0104] In another embodiment, a barrier coating (311) is also provided on the surface of the resistance heating element (40). The addition of this barrier coating (311) enhances the stability of the resistance heating element (40), which typically relies on an adherent, stable, and dense surface oxide layer that acts as a barrier against further oxidation / contact between the bulk metal material and the external environment. Furthermore, the barrier coating (311) further enhances resistance to carbon diffusion, which can lead to carburization and metal pulverization of the resistance heating element (40). This is particularly relevant in cases involving steam cracking in high-carbon environments / atmospheres.

[0105] In another embodiment, in addition to the barrier coating (311), a structured ceramic bed (30) may support a catalytically active coating (312), which gasifies coke generated by the heat of vapor-phase free radical reaction from steam cracking. The catalytically active coating (312) converts solid carbon after undergoing a well-known gasification reaction, which primarily involves H2O or CO2 as co-reactants.

[0106] In another embodiment, a catalytically active coating (312) is provided on the surface of the resistance heating element (40). The catalytically active coating (312) activates carbon gasification after an endothermic reaction using H2O or CO2 present in the reactive mixture stream. Thus, the endothermic reaction occurring on the surface of the resistance heating element (40) acts as an energy receiver to further reduce the surface temperature of the resistance heating element (40). As a result, lifetime is maximized.

[0107] Adding a barrier coating (311) and / or a catalytically active coating (312) can minimize the formation and accumulation of coke that could clog the hollow channels (32). At the same time, it avoids the accumulation of heat transfer resistance and pressure drop, as well as the need to regenerate the reactor by using air and / or steam through coke gasification, which would cause reactor shutdown.

[0108] The resistance heating element (40) benefits from the mechanical support and geometric constraints provided by the structured ceramic bed (30). Due to this configuration, and the extremely high stability of the longitudinally shaped resistance heating element (40), particularly due to the presence of a barrier coating (311) or a catalytically active coating (312), the maximum surface load, operating temperature, and lifespan of the electric heating device (40) are significantly increased compared to any other device disclosed. The surface load is not limited by electromagnetic forces, thermal expansion, or the lower physical properties caused by extremely high operating temperatures up to 1200°C. As a result, the configuration disclosed herein achieves speeds exceeding 100 kWm at surfaces in direct contact with the reactive mixture flow. -2 The heat flux is high. The power per volumetric volume can also reach 30 MWm. -3 Table 1 provides the characteristics of the disclosed equipment.

[0109] Table 1 - Features of the apparatus disclosed herein

[0110]

[0111] When using a coated structured ceramic bed (30) with a resistance heating element (40) for steam cracking as disclosed herein, it is possible to:

[0112] - Maximize the surface-to-volume ratio

[0113] - Maximize reaction temperature

[0114] - Maximize power per volume

[0115] - Minimize dwell time

[0116] - Minimize pressure drop

[0117] - Reduce carbon dioxide emissions

[0118] - Improve thermal efficiency.

[0119] Because electric heating is used, the emission concentration is typically around 50 mg / m³. -3 Up to 100mg m -3 NO between x The generation of [something] can be avoided. In addition, since there is no flue gas, there is no need to build separate furnace convection sections and chimneys for recovering heat and venting flue gas.

[0120] exist Figure 2 In the illustrated embodiment, at least two reaction sections (23) are located in the same reactor shell (10). This minimizes the number of parallel reactor shells (10) and thus minimizes the cost of the steam cracker, which is considered to be a component of multiple parallel electrically heated reactor shells (10).

[0121] The product stream is collected in the collection section (24) and eventually reaches the product stream outlet (25) before leaving the reactor shell (10). In an embodiment with two reaction sections (23), a diversion section (111) diverts all product streams toward the product stream outlet (25). The diversion section (111), located within the collection section (24), facilitates the discharge of the product stream, avoiding potential accumulation and / or backmixing effects. The diversion section (111), located within the collection section (24), can have any geometry, including any parabolic structure. The diversion section (111) reduces the residence time distribution of the product stream within the reactor shell (10), thereby minimizing carbon formation and the yield of secondary unwanted products. The disclosed reactor shell (10) and associated collection section (24) are capable of accommodating an improved diversion section (111) that cannot be installed in conventional steam cracking reactor configurations.

[0122] If any coking is present, it accumulates in the deposition chamber (241) located in the collection section (24) and does not obstruct the product stream to the product stream outlet (25). Furthermore, the deposition chamber (241) can collect any ceramic components should the structured ceramic bed (30) be damaged. Due to this configuration, the product stream does not carry any foreign matter that could potentially clog the product stream outlet (25) or downstream equipment. Because the disclosed reactor shell (10) and process are well integrated with existing upstream and downstream facilities, conventional systems for heat recovery from the product stream (transfer line exchanger) and downstream fractionation units still exist. In this case, multiple electrified steam crackers are connected in parallel to the downstream equipment via manifolds. The possibility of using pipes and manifolds with internal refractory linings, allowing operation at lower metal temperatures, facilitates mechanical design and construction without the need for expensive and complex metal compensators or bellows to accommodate thermal expansion of the metal.

[0123] The aforementioned reactor shell (10) structure and the steam cracking process it enables avoid fuel combustion, reducing CO2 emissions by at least 80%; from producing more than 1 ton of CO2 per ton of ethylene to producing 0.2 ton of CO2 per ton of ethylene. Zero CO2 emissions are also possible because the steam cracking process disclosed herein facilitates CO2 capture; CO2 exists only in the product stream and is not diluted by nitrogen in the high-flow-rate flue gas leaving the combustion furnace.

[0124] The following results can be obtained through the above-described system and process for producing olefins by steam cracking:

[0125] - Minimize the characteristic length scale used for heat transfer, thereby minimizing the temperature gradient within the reaction section (23);

[0126] - By minimizing the temperature gradient, the necessary steam-to-carbon ratio is minimized;

[0127] - Due to the high product selectivity, the downstream separation and purification process is simplified;

[0128] - Minimize capital costs due to the amplification (learning factor) of process enhancement and modular factory configuration;

[0129] - Maximize the utilization of the reaction temperature of the direct contact resistance heating element (40);

[0130] - The pressure drop is minimized due to the high porosity of the structured ceramic bed (30);

[0131] - Due to the enhanced adhesion and stability of the barrier coating (311) and / or the catalytically active coating (312), the peeling of the coated structured ceramic bed (30) and the resistance heating element (40) is minimized.

[0132] - Due to the barrier coating (311) and / or the catalytically active coating (312), carbon formation is minimized, which can lead to longer operability before the necessary regeneration is carried out by coke gasification.

[0133] - By minimizing temperature gradient, pressure drop, and residence time, product selectivity is improved;

[0134] - The possibility of developing renewable electricity to use cheap energy;

[0135] - The possibility of converting free electrons into chemical energy using traditional and widely used thermochemical processes;

[0136] - The possibility of stabilizing the power grid to regulate reactor capacity;

[0137] Other advantages associated with the manufacture and installation of the reactor shell (10) are shown below.

[0138] The disclosed reactor shell (10) configuration enables operation of the reactor at cold surface temperatures, thus minimizing the cost of building materials. All mechanical parts are manufactured from cryogenic steel, significantly reducing the plant's capital costs.

[0139] The reactor shell (10) avoids the construction of expensive and complex combustion furnaces containing burners and reactor coils (i.e., combustion chambers), as well as economizers, preheaters, and superheaters involving convection sections. The absence of flue gas drastically reduces residual steam, currently preventing the conversion from steam to electrically driven equipment such as compressors.

[0140] The process, implemented using multiple reactor shells (10), enables modularization of the equipment, minimizing variations in plant productivity during routine and / or non-routine maintenance of plant sub-units.

[0141] Due to the rapid dynamics of the resistance heating element, the disclosed design enables rapid start-up and shutdown of the steam pyrolysis process. Furthermore, the cumulative volume of the steam pyrolysis unit is at least two orders of magnitude smaller than that of prior art combustion pyrolysis furnaces. The reactor has a lower heat capacity and faster dynamics. Within the disclosed configuration, temperatures above 30°C / min can be achieved. -1 The heating rate. This enables the segmented coupling (energy system integration) between the chemical and power sectors required to achieve a climate-neutral economy. The reactor shell (10) can vary its energy consumption, thereby enabling its productivity to stabilize the power grid. In this way, the plant operator creates new and additional revenue streams.

[0142] The reactor system of this application can replace existing pyrolysis furnaces or be integrated into auxiliary plant sections to improve productivity, flexibility and / or compensate for downtime of existing combustion steam pyrolysis furnaces (by debottlenecking and / or partial / gradual retrofitting).

[0143] The steam cracking process described in this application can be applied to both conventional centralized steam cracking units used in existing petrochemical plants and decentralized applications. The compact, inexpensive, and modular technology will help achieve zero-path gas combustion.

Claims

1. A reactor shell (10) for the production of olefins from a feed reactive mixture consisting of steam and hydrocarbons by steam cracking, characterized in that comprising: at least one reaction stream conduit (20) formed within said reactor housing (10) having at least one reaction stream inlet (21) for the flow of the reactive mixture, a product stream outlet (25) for the flow of the olefin product stream out of said reactor housing (10) and at least one reaction section (23) disposed between said reaction stream inlet (21) and said product stream outlet (25), an insulating packing (11) at least partially surrounding said reaction stream conduit (20), at least one structured ceramic bed (30) housed in said reaction section (23) and having a plurality of hollow flow channels (32) configured to allow the flow of the reactive mixture stream therethrough, at least one electrically resistive heating element (40) comprising a serpentine section (41) arranged inside at least some of said hollow flow channels (32) in such a way that the flow passage (323) remains within said hollow flow channels (32), connected to at least two electrical feed sources (51) and powered by an electrical power source (50) configured to heat the flow of the reactive mixture to a temperature that initiates a non-catalytic gas phase free radical reaction of steam cracking, a coating (31) selected from a barrier coating (311) or a catalytically active coating (312) disposed on the surface in contact with the flow of the reactive mixture, thereby minimizing the deposition of coke; wherein said electrically resistive heating element (40) is inserted from a flow channel inlet (321) of a first hollow flow channel (32), exits from an opposite side flow channel outlet (322) of said first hollow flow channel (32), enters a second hollow flow channel (32), exits and continues to advance in the remaining hollow flow channels (32) of said structured ceramic bed (30).

2. The reactor housing (10) according to claim 1, wherein said electrically resistive heating element (40) is an electrically resistive wire or an electrically resistive tape.

3. The reactor housing (10) according to claim 1 or 2, wherein said electrically resistive heating element (40), said electrical feed sources (51) and said electrical power source (50) are configured to heat the flow of the reactive mixture to a temperature of 1200°C.

4. The reactor housing (10) according to claim 1 or 2, wherein said structured ceramic bed (30) is a monolithic piece or a combination of a plurality of ceramic sub-units arranged in a side-by-side manner forming a plurality of flow channels (32).

5. The reactor housing (10) according to claim 1, wherein said reaction stream conduit (20) further comprises a distribution section (22) formed in an extension of said reaction stream inlet (21) for distributing the flow of the reactive mixture in said reaction section (23) and a collection section (24) formed in an extension of said reaction section (23) for collecting the product stream and diverting it towards said product stream outlet (25).

6. The reactor housing (10) according to claim 1 or 2, comprising two reaction sections (23) arranged in line in the same direction, wherein the insulation filler (11) has a split section (111) in between, thereby diverting all product flow towards the product flow outlet (25).

7. The reactor housing (10) according to claim 1, wherein the material of the structured ceramic bed (30) is selected from the group consisting of Si02, AI2O3, Y2O3, WO3, Zr02, Ti02, MgO, CaO, Ce02and mixtures thereof.

8. The reactor housing (10) according to claim 1, wherein the material of the coating (31) comprises elements from the group IIA, IIIB, IVB, VIIB, IIIA, IVA of the periodic table.

9. The reactor housing (10) according to claim 1, wherein the coating (31) is arranged on the surface of the hollow flow channel (32) facing the resistive heating element (40).

10. The reactor housing (10) according to claim 1, wherein the coating (31) is arranged on the surface of the resistive heating element (40) facing the structured ceramic bed (30).

11. The reactor housing (10) according to claim 1, wherein the coating (31) is a barrier coating (311) preventing contact between the reactive mixture flow and the structured ceramic bed (30) and / or the resistive heating element (40).

12. The reactor housing (10) according to claim 1, wherein the coating (31) is a catalytically active coating (312) that gasifies coke produced during thermal steam cracking gas phase free radical reactions.

13. The reactor housing (10) according to claim 1, wherein the hydrocarbons in the feed reactive mixture flow are selected from the group consisting of naphtha, ethane, propane, gasoline, liquefied petroleum gas.

14. The reactor housing (10) of claim 1, wherein the material of the resistive heating element (40) is a FeCrAl alloy or another material having an electrical resistivity of 1 x 10 7 5 5 Ω m to 1 x 10 5 Ω m.

15. A method for producing olefins from a feed reactive mixture of steam and hydrocarbons by steam cracking, the method flowing through a reactor housing (10) comprising at least one reaction flow conduit (20) having a reaction flow inlet (21), a product flow outlet (25), and a reaction section (23) disposed between the reaction flow inlet (21) and the product flow outlet (25), an insulation packing (11) at least partially surrounding the reaction flow conduit (20), at least one structured ceramic bed (30) housed in the reaction section (23) and having a plurality of hollow flow channels (32) configured to allow the reactive mixture to flow therethrough, at least one resistive heating element (40), and a coating (31). The at least one resistive heating element (40) is powered by at least two electrical feeds (51) connected to an electrical power source (50) and is configured to heat the reactive mixture flow to a predetermined temperature that initiates non-catalytic gas phase free radical reactions of steam cracking, the coating (31) is arranged on a surface in contact with the reactive mixture flow, the coating (31) is selected from a barrier coating (311) or a catalytically active coating (312) arranged on a surface in contact with the reactive mixture flow, thereby minimizing coke deposition, the method comprising the steps of: placing the electrically resistive heating element (40) within the hollow flow channel (32) in a manner such that the flow channel (323) remains within the hollow flow channel (32) and extends coaxially with the flow direction of the reactive mixture stream, wherein the electrically resistive heating element (40) is inserted from the flow channel inlet (321) of a first hollow flow channel (32), exits from the opposite side flow channel outlet (322) of the first hollow flow channel (32), enters a second hollow flow channel (32), exits, and continues in the remaining hollow flow channels (32) of the structured ceramic bed (30), energizing the electrically resistive heating element (40) by a power supply (50) to heat the reactive mixture stream to 1200 °C, feeding a reactive mixture stream having a temperature of 400 °C to 700 °C and a pressure of 1 bar to 10 bar through the reaction stream inlet (21) into the reactor housing (10), passing the reactive mixture stream through the hollow flow channels (32) in a manner such that the reactive mixture stream contacts the electrically resistive heating element (40) and the structured ceramic bed (30), causing an olefin product stream to exit from the product stream outlet (25).

16. The method of claim 15, wherein the reactive mixture stream undergoes a non- catalytic gas phase free radical reaction of steam cracking in the reaction section (23).

17. The method of claim 15, wherein the material of the coating (31) comprises elements from groups IIA, IIIB, IVB, VIIB, IIIA, IVA of the periodic table.

18. The method of claim 15, wherein the coating (31) is selected from a barrier coating (311) or a catalytically active coating (312) disposed on a surface of the hollow flow channel (32) facing the electrically resistive heating element (40) in contact with the reactive mixture stream, thereby minimizing coke deposition.

19. The method of claim 18, wherein the coating (31) is also disposed on a surface of the electrically resistive heating element (40) facing the structured ceramic bed (30).

20. The method of claim 15, wherein a meandering section (41) of the electrically resistive heating element (40) remains outside of the hollow flow channel (32) and the electrically resistive heating element (40) is inserted from the flow channel inlet (321) of a first hollow flow channel, exits from the opposite side flow channel outlet (322) of the first hollow flow channel (32), then the electrically resistive heating element (40) enters a second hollow flow channel (32), exits, and continues in the remaining hollow flow channels (32).

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