Method for treating chemicals and reactor system utilizing a tubular reactor

Abstract

A method for processing a chemical may include passing a hydrocarbon feed stream through an inlet of a tubular reactor at least partially disposed within an enclosure. The enclosure may include at least one heating element disposed between an inner surface of a sidewall of the enclosure and an outer surface of a wall of the tubular reactor. The method includes passing a first electric current through the wall of the tubular reactor to heat at least a portion of the wall of the tubular reactor and passing a second electric current through the heating element to heat the heating element such that heat is transferred from the heating element to the wall of the tubular reactor. The method includes reacting at least a portion of the hydrocarbon feed stream in the tubular reactor to form a product stream and passing the product stream through an outlet of the tubular reactor.

Description

[Technical Field]

[0001] (CROSS-REFERENCE TO RELATED APPLICATIONS) This application claims the benefit of U.S. Provisional Patent Application No. 63 / 432,168, filed December 13, 2023, the entire disclosure of which is incorporated herein by reference.

[0002] FIELD OF THE INVENTION FIELD OF THE INVENTION The embodiments described herein generally relate to methods and systems for chemical processing. [Background technology]

[0003] A variety of chemicals can be produced by reacting feed streams to form product streams in reactor systems, such as tubular reactors. Some reactions that can occur in such reactor systems are endothermic, such as steam cracking and steam methane reforming. Heat may be supplied to the reactor system to drive such reactions.

[0004] Conventional heating methods rely on on-site combustion of fossil fuels to provide process heat, which can result in greenhouse gas emissions. For example, some conventional reactor systems use multiple fuel gas burners to radiate heat from the combustion of fuel gas onto the tubular reactor walls, providing heat through the walls to the hydrocarbon feedstock and driving endothermic reactions to form desired products. The increasing availability of renewable electricity creates opportunities to provide heat using renewable energy, eliminating the need to burn fossil fuels, which leads to lower emissions. Therefore, there is a need for improved systems and methods for processing chemicals using electricity to provide heat to a reactor system. Summary of the Invention

[0005] Embodiments of the present disclosure relate to a reactor system that uses electricity to provide heat to a tubular reactor using both electric radiant heating and direct resistive heating techniques. The reactor system may include one or more tubular reactors disposed within an enclosure. Electric heating elements can be disposed within the enclosure to heat the tubular reactor by radiant heating. Additionally, the walls of the tubular reactor itself may be heated by direct electrical resistance heating. A combination of radiant heating from the electric heating elements and direct resistive heating of the tubular reactor walls can provide the heat necessary to promote endothermic reactions within the tubular reactor. Furthermore, without being bound by any particular theory, the use of both radiant and resistive heating may allow the reactor system to have greater operational flexibility, reduce mechanical stress within the reactor system, allow the use of less exotic materials for the tubular reactor and heating elements, and allow greater freedom in positioning the heating elements and tubular reactor within the reactor system. Therefore, the combination of direct resistive heating and radiant heating may be advantageous over conventional heating methods.

[0006] According to one or more embodiments of the present disclosure, a method for processing a chemical may include passing a hydrocarbon feed stream through an inlet of a tubular reactor. The tubular reactor may include an inlet, an outlet, and a wall extending at least from the inlet to the outlet. The tubular reactor may be at least partially disposed within an enclosure. The enclosure may include a first end, a second end, and at least one sidewall extending from the first end to the second end. The enclosure may include at least one heating element disposed between an inner surface of the sidewall of the enclosure and an outer surface of the wall of the tubular reactor. The method for processing a chemical may include passing a first electric current through at least a portion of the wall of the tubular reactor to heat at least a portion of the wall of the tubular reactor, and passing a second electric current through the heating element to heat at least a portion of the heating element such that heat is transferred from the heating element to the wall of the tubular reactor. The method includes reacting at least a portion of the hydrocarbon feed stream in the tubular reactor to form a product stream, and passing the product stream through an outlet of the tubular reactor.

[0007] According to one or more additional embodiments of the present disclosure, a reactor system may include a tubular reactor including an inlet, an outlet, and a wall extending at least from the inlet to the outlet. The wall of the tubular reactor may be connected to a first current source such that at least a portion of the tubular reactor is heated when a first current is passed through the tubular reactor. The reactor system may include a housing including a first end, a second end, and at least one sidewall extending from the first end to the second end, and at least one heating element disposed between an inner surface of the sidewall of the housing and an outer surface of the wall of the tubular reactor. The heating element may be connected to a second current source. The tubular reactor may be at least partially disposed within the housing such that the heating element is operable to heat at least a portion of the tubular reactor when a second current is passed through the heating element.

[0008] Additional features and advantages of the techniques disclosed herein will be set forth in the detailed description that follows, and in part will be readily apparent to those skilled in the art from that description, or will be learned by practicing the techniques as described herein, including the detailed description, claims, and accompanying drawings. [Brief explanation of the drawings]

[0009] The following detailed description of certain embodiments of the present disclosure can be best understood when read in conjunction with the following drawings, in which like structure is indicated with like reference numerals and in which: [Figure 1] FIG. 1 is a schematic diagram of a reactor system comprising a tubular reactor according to one or more embodiments disclosed herein. [Figure 2] FIG. 1 is a schematic diagram of a reactor system comprising a tubular reactor having a "U" shape, according to one or more embodiments described herein. [Figure 3] FIG. 1 is a schematic diagram of a reactor system comprising multiple tubular reactors according to one or more embodiments described herein. DETAILED DESCRIPTION OF THE INVENTION

[0010] One or more non-limiting embodiments are described herein. As described herein, a method for processing a chemical may include passing a hydrocarbon feed stream through an inlet of a tubular reactor, reacting at least a portion of the hydrocarbon feed stream to form a product stream, and passing the product stream from the tubular reactor. The tubular reactor may be disposed within an enclosure, and the tubular reactor may be heated by radiative heating from heating elements disposed within the enclosure and by resistive heating of the walls of the tubular reactor. Without being bound by theory, the use of both radiative and resistive heating may allow the system to have greater operational flexibility, may reduce mechanical stress within the reactor system, may allow the use of less specialized materials for the tubular reactor and heating elements, and may allow greater freedom in positioning the heating elements and tubular reactor within the reactor system. These advantages, as well as others, are described in detail below.

[0011] Referring now to FIG. 1 , a hydrocarbon feed stream 102 may be passed through a tubular reactor 110. FIG. 1 illustrates a cross section of the tubular reactor 110, as would be understood by one of ordinary skill in the art. As described herein, a "reactor" refers to a vessel suitable for a given chemical reaction. A "tubular reactor" may refer to a reactor having a substantially tubular shape such that reactants and products pass from an inlet to an outlet of the reactor. Tubular reactors are described in more detail below. The tubular reactor 110 may be part of a reactor system 100. The reactor system 100 may include one or more tubular reactors 110 and a housing 120, as described in more detail herein.

[0012] In one or more embodiments, the tubular reactor 110 may include an inlet 111, an outlet 112, and a wall 113. The wall 113 may have a substantially circular cross-sectional shape. The wall may include an inner surface 115 and an outer surface 114. The wall 113 may extend from at least the inlet 111 to the outlet 112 of the tubular reactor 110. In one or more embodiments, the wall 113 may extend from the inlet 111 to the outlet 112 of the tubular reactor 110. In such embodiments, the inlet 111 and the outlet 112 may be located at opposite ends of the tubular reactor 110. In one or more embodiments not shown, the wall 113 may extend beyond the inlet 111 or the outlet 112, or both. In such embodiments, the inlet 111 or the outlet 112 may not be located exactly at the ends of the tubular reactor 110. However, the inlet 111 and outlet 112 may be located sufficiently close to the end of the tubular reactor 110 so as not to significantly impair the functionality of the tubular reactor 110. For example, the inlet 111 or outlet 112 may be an opening in the wall 113 of the tubular reactor 110 that is close to the end of the tubular reactor 110, but the end of the tubular reactor 110 is closed.

[0013] In one or more embodiments, the tubular reactor 110 may have a cross-sectional area that is substantially constant from the inlet 111 of the tubular reactor 110 to the outlet 112 of the tubular reactor 110. As described herein, the cross-sectional area of ​​the tubular reactor 110 is perpendicular to the bulk flow of the hydrocarbon feed stream through the tubular reactor 110. As described herein, a cross-sectional area may be "substantially constant" if it varies by less than 15%, less than 10%, less than 5%, or even less than 1% over the length of the tubular reactor 110 from the inlet 111 of the tubular reactor 110 to the outlet 112 of the tubular reactor 110. It should be noted that individual particles or molecules within a phase can move in a direction different from, or even opposite to, the bulk flow of a phase without affecting the direction of the bulk flow of that phase. For example, but not by way of limitation, individual hydrocarbon molecules within the hydrocarbon feed stream 102 may move in a direction different from the bulk flow of the hydrocarbon feed stream 102 without affecting the direction of the bulk flow of the hydrocarbon feed stream 102. In one or more embodiments, the bulk flow of the hydrocarbon feed stream 102 through the tubular reactor 110 may be substantially plug flow from the inlet 111 of the tubular reactor 110 to the outlet 112 of the tubular reactor 110.

[0014] The tubular reactor 110 may have any suitable cross-sectional shape. In one or more embodiments, the tubular reactor 110 may have a closed curved cross-sectional shape, a polygonal cross-sectional shape, or a combination thereof. For example, without limitation, the tubular reactor 110 may have a cross-sectional shape such as a circle, an oval or ellipse, a triangle, a rectangle, a pentagon, a hexagon, or the like, or a combination thereof. In some embodiments, the tubular reactor 110 may have a substantially circular cross-sectional shape.

[0015] In one or more embodiments, the wall 113 of the tubular reactor 110 may include one or more bends between the inlet 111 of the tubular reactor 110 and the outlet 112 of the tubular reactor 110. For example, without limitation, the wall 113 of the tubular reactor 110 may include a single bend and may have a "U" shape, or the wall 113 of the tubular reactor 110 may include two or more bends and may have an "S" shape, an "M" shape, a "W" shape, or other shape. Referring now to FIG. 2, in some embodiments, the wall 113 of the tubular reactor 110 includes a single bend and the tubular reactor 110 has a "U" shape.

[0016] 1 , the wall 113 of the tubular reactor 110 may be straight or substantially free of bends. In such embodiments, the wall 113 of the tubular reactor 110 may have a substantially hollow cylindrical shape. As described herein, a hollow cylindrical shape has a circular cross-sectional shape when the cross section is a radial cross section relative to the hollow cylinder.

[0017] The tubular reactor 110 can be at least partially disposed within a housing 120. In one or more embodiments, the housing 120 can include a first end 121, a second end 122, and at least one sidewall 123 extending from the first end 121 to the second end 122. In one or more embodiments, the at least one sidewall 123 can have an inner surface 124. The inner surface 124 of the at least one sidewall 123 can be spaced apart from the outer surface 114 of the wall 113 of the tubular reactor 110. In other words, the inner surface 124 of the at least one sidewall 123 of the housing 120 does not have to be in direct contact with the outer surface 114 of the wall 113 of the tubular reactor 110. For example, conductive heating by the heating element 130 may not be possible for the tubular reactor 110.

[0018] In one or more embodiments, the inlet 111 of the tubular reactor 110 may be located at the first end 121 of the housing 120, and the outlet 112 of the tubular reactor 110 may be located at the second end 122 of the housing. In such embodiments, the tubular reactor 110 may span the housing 120 from the first end 121 of the housing 120 to the second end 122 of the housing. In one or more embodiments, the wall 113 of the tubular reactor may include one or more bends, and the inlet 111 of the tubular reactor 110 and the outlet 112 of the tubular reactor may be located at the same end of the housing 120. For example, without limitation, the inlet 111 of the tubular reactor 110 and the outlet 112 of the tubular reactor 110 may both be at the first end 121 of the housing 120 or at the second end 122 of the housing. Referring again to the embodiment shown in FIG. 2, the inlet 111 and outlet 112 of the tubular reactor 110 are both located at a first end 121 of the housing 120 .

[0019] Referring now to FIG. 3, two or more tubular reactors 110 may be at least partially disposed within the housing 120. For example, in the embodiment shown in FIG. 3, two tubular reactors 110a and 110b are disposed within the housing 120. In one or more embodiments, between 2 and 50 tubular reactors 110 may be disposed within the housing 120. For example, without limitation, the number of tubular reactors 110 disposed within the housing 120 may be between 2 and 50, between 10 and 50, between 20 and 50, between 30 and 50, between 40 and 50, between 2 and 40, between 2 and 30, between 2 and 20, between 2 and 10, or any combination or subset of these endpoints. Generally, each tubular reactor 110 may be in direct line of sight with one or more heating elements 130.

[0020] In embodiments in which two or more tubular reactors 110 are at least partially disposed within the enclosure 120, the reactor system 100 may further comprise an inlet manifold 211 for fluidly connecting the inlets 111 of each tubular reactor 110. In the embodiment shown in Figure 3, the inlet manifold 211 fluidly connects the inlet 111a of the tubular reactor 110a with the inlet 111b of the tubular reactor 110b so that the hydrocarbon feed stream 102 can be passed through both the inlet 111a and the inlet 111b. Additionally, the reactor system 100 may comprise an outlet manifold 112 for fluidly connecting the outlets 112 of each tubular reactor 110. Still referring to Figure 3, the outlet manifold 212 fluidly connects the outlet 112a of the tubular reactor 110a with the outlet 112b of the tubular reactor 110b so that the product stream 104 can be routed from the tubular reactors 110a and 110b. It should be noted that the inlet manifold 211 and the outlet manifold 212 may be configured to accommodate any number of tubular reactors 110 disposed within the enclosure 120 .

[0021] Referring again to FIG. 1 , the wall 113 of the tubular reactor 110 can be connected to a first current source 131. By passing a first current through the wall 113 of the tubular reactor 110, the wall of the tubular reactor 110 can be heated by electrical resistance heating. Without being bound by theory, the electrical resistance heating can occur through the "Joule effect." According to Joule's first law, the thermal power generated by an electrical conductor is proportional to its resistance times the square of the current. Joule's first law is given by Equation 1, where P is power, I is current, and R is resistance. P=I 2 R formula 1.

[0022] In one or more embodiments, the wall 113 of the tubular reactor 110 may be connected to a first current source 131 proximate the inlet 111 of the tubular reactor 110 and the outlet 112 of the tubular reactor. For example, without limitation, the first current source 131 may be connected to the wall 113 of the tubular reactor 110 at a location within 5%, 10%, 15%, or even 20% of the length of the wall 113 from the inlet 111 of the tubular reactor 110. Similarly, the first current source 131 may be connected to the wall 113 of the tubular reactor 110 at a location within 5%, 10%, 15%, or even 20% of the length of the wall 113 from the outlet 112 of the tubular reactor 110.

[0023] In one or more embodiments, the wall 113 of the tubular reactor 110 may be further connected to a first current source 131. For example, without limitation, a third connection to the first current source 131 may be made between connections proximate the inlet 111 and the outlet 112. In one or more embodiments, the third connection between the first current source 131 and the wall 113 of the tubular reactor 110 may be made within 5%, 10%, 15%, or even 20% of the length of the wall 113 from the midpoint of the wall 113 from the inlet 111 to the outlet 112 of the tubular reactor 110. Without being bound by theory, when a third connection is made between the wall 113 of the tubular reactor 110 and the first current source 131, two heating zones may be formed within the wall 113 of the tubular reactor 110. It is contemplated that these heating zones may be independently controlled to create two heating zones within the tubular reactor 110. In one or more embodiments, additional connections between the first current source 131 and the wall 113 of the tubular reactor 110 can be made to create additional heating zones within the tubular reactor 110 .

[0024] In one or more embodiments, the wall 113 of the tubular reactor 110 may be electrically conductive. In one or more embodiments, the wall 113 of the tubular reactor 110 may have a resistivity of 1.0 to 4.0 μΩ·m at 900°C, 1.0 to 3.5 μΩ·m at 900°C, 1.0 to 3.0 μΩ·m at 900°C, 1.0 to 2.5 μΩ·m at 900°C, 1.0 to 2.0 μΩ·m at 900°C, 1.0 to 1.5 μΩ·m at 900°C, 1.5 to 4.0 μΩ·m at 900°C, 1.5 to 3.5 μΩ·m at 900°C, 1.5 to 3.0 μΩ·m at 900°C, 1.5 to 2.5 μΩ·m at 900°C, The wall 113 of the tubular reactor 110 may have an electrical resistivity of 1.5 to 2.0 μΩ·m at 0° C., 2.0 to 4.0 μΩ·m at 900° C., 2.0 to 3.5 μΩ·m at 900° C., 2.0 to 3.0 μΩ·m at 900° C., 2.0 to 2.5 μΩ·m at 900° C., 2.5 to 4.0 μΩ·m at 900° C., 2.5 to 3.5 μΩ·m at 900° C., 2.5 to 3.0 μΩ·m at 900° C., 3.0 to 4.0 μΩ·m at 900° C., 3.0 to 3.5 μΩ·m at 900° C., or 3.5 to 4.0 μΩ·m at 900° C. In one or more embodiments, the electrical resistivity of the wall 113 of the tubular reactor 110 may vary over the length of the wall 113.

[0025] In one or more embodiments, the tubular reactor 110 can have an inner diameter of 1 to 6 inches (in), 1 to 5 in, 1 to 4 in, 1 to 3 in, 1 to 2 in, 2 to 6 in, 2 to 5 in, 2 to 4 in, 2 to 3 in, 3 to 6 in, 3 to 5 in, 3 to 4 in, 4 to 6 in, 4 to 5 in, or 5 to 6 in. In one or more embodiments, the tubular reactor wall 113 can have a thickness of 0.1 to 1.5 in, 0.1 to 1.25 in, 0.1 to 1.0 in, 0.1 to 0.75 in, 0.1 to 0.5 in, 0.1 to 0.25 in, 0.25 to 1.5 in, 0.25 to 1.25 in, 0.25 to 1.0 in, 0.25 to 0.75 in, 0.25 to 0.5 in, 0.5 to 1.5 in, 0.5 to 1.25 in, 0.5 to 1.0 in, 0.5 to 0.75 in, 0.75 to 1.5 in, 0.75 to 1.25 in, 0.75 to 1.0 in, 1.0 to 1.5 in, 1.0 to 1.25 in, or 1.25 to 1.5 in. In one or more embodiments, the wall 113 of the tubular reactor 110 can have a length of 10 to 60 meters (m), 10 to 50 m, 10 to 40 m, 10 to 30 m, 10 to 20 m, 20 to 60 m, 20 to 50 m, 20 to 40 m, 20 to 30 m, 30 to 60 m, 30 to 50 m, 30 to 40 m, 40 to 60 m, 40 to 50 m, or 50 to 60 m. It is contemplated that the inner diameter, wall thickness, or both can vary over the length of the wall 113 of the tubular reactor 110.

[0026] The first current source 131 may be any suitable source of electrical current. The first current source 131 may be operable to provide alternating or direct current to the wall 113 of the tubular reactor 110. For example, without limitation, a suitable current source may be a commercially available step-down transformer, such as a thyristor-based transformer manufactured by Fuji Electric.

[0027] In one or more embodiments, at least a portion of the wall 113 of the tubular reactor 110 can be heated by passing a first electric current through the wall 113 of the tubular reactor 110. In one or more embodiments, the wall 113 of the tubular reactor 110 can be heated to a temperature of 600° C. to 1100° C. For example, but not limited to, the wall 113 of the tubular reactor 110 can be heated to a temperature of 600° C. to 1100° C., 700° C. to 1100° C., 800° C. to 1100° C., 900° C. to 1100° C., 1000° C. to 1100° C., 600° C. to 1000° C., 600° C. to 900° C., 600° C. to 800° C., 600° C. to 700° C., or any combination or subset of these ranges.

[0028] 1 , the housing 120 may include at least one heating element 130 disposed between an inner surface 124 of a sidewall 123 of the housing 120 and an outer surface 114 of the tubular reactor 110. The heating element 130 may be operable to convert electricity into heat. Suitable heating elements may be described in WO 2020 / 002326(A1), which is incorporated herein by reference in its entirety.

[0029] In one or more embodiments, the heating element 130 may convert electricity to heat by electrical resistance heating, as described above. In one or more embodiments, the heating element 130 may include NiCr, SiC, MoSi, graphite, or FeCrAl as a material through which an electric current is passed to generate heat. In one or more embodiments, the heating element 130 may include silicon carbide (SiC). In one or more embodiments, the heating element 130 may take any suitable form. For example, without limitation, the heating element 130 may include round wire, rectangular wire, stranded wire, strip, rod, rod-over-band, etc. In one or more embodiments, the heating element 130 may be resistant to exposure to air, hydrocarbons, and steam. Without intending to be bound by theory, the heating element may be resistant to hydrocarbons and steam, and therefore, the heating element will not be damaged if hydrocarbons or steam are released due to a failure of one of the tubular reactors resulting in the release of reactants, products, or both. However, it should be noted that suitable heating elements are not limited to those that are resistant to exposure to hydrocarbons or vapors.

[0030] In one or more embodiments, the heating element 130 has a thermal conductivity of 1.0-4.0 μΩ·m at 900°C, 1.0-3.5 μΩ·m at 900°C, 1.0-3.0 μΩ·m at 900°C, 1.0-2.5 μΩ·m at 900°C, 1.0-2.0 μΩ·m at 900°C, 1.0-1.5 μΩ·m at 900°C, 1.5-4.0 μΩ·m at 900°C, 1.5-3.5 μΩ·m at 900°C, 1.5-3.0 μΩ·m at 900°C, 1.5-2.5 μΩ·m at 900°C, The resistivity may be 1.5 to 2.0 μΩ·m at 900°C, 2.0 to 4.0 μΩ·m at 900°C, 2.0 to 3.5 μΩ·m at 900°C, 2.0 to 3.0 μΩ·m at 900°C, 2.0 to 2.5 μΩ·m at 900°C, 2.5 to 4.0 μΩ·m at 900°C, 2.5 to 3.5 μΩ·m at 900°C, 2.5 to 3.0 μΩ·m at 900°C, 3.0 to 4.0 μΩ·m at 900°C, 3.0 to 3.5 μΩ·m at 900°C, or 3.5 to 4.0 μΩ·m at 900°C.

[0031] The enclosure 120 may include two or more heating elements 130. It should be noted that the number of heating elements 130 disposed within the enclosure 120 may depend on the dimensions of the enclosure 120, the number of tubular reactors 110 within the enclosure 120, the positions of the tubular reactors 110 within the enclosure 120, the desired temperatures of the tubular reactors 110, and the desired heat flux from the heating elements 130 to the tubular reactors 110. Without being bound by theory, when multiple heating elements 130 are disposed within the enclosure 120, the heating elements 130 may be controlled in groups or individually. Separately controlling groups of heating elements 130 may allow for independent control of various heating zones within the enclosure 120.

[0032] In one or more embodiments, the heating element 130 is connected to a second current source 132. The second current source 132 may be any suitable current source. The second current source 132 may be operable to provide either AC or DC current to the heating element 130. For example, without limitation, a suitable current source may be a commercially available step-down transformer, such as a thyristor-based transformer manufactured by Fuji Electric. In one or more embodiments, the power source 132 may include a silicon-controlled rectifier (SCR), which provides a discontinuous current to a resistive element, or a variable voltage power supply, which provides continuous voltage changes in discrete steps. Current from the latter may be measured using conventional means. However, the current output from SCR and thyristor power supplies is inherently discontinuous, and accurate measurement of the resulting discontinuous current may utilize techniques that account for the non-sinusoidal nature of the output waveform. In one or more embodiments, multiple heating elements 130 may be connected in series or parallel, or a combination thereof, to adjust the total heater circuit resistance, heater zone design, and voltage and current for the heating elements (e.g., material electrical resistivity, geometry, cross-sectional area, and element length) so that a desired heating power is achieved. Note that the amount of current flowing from the first current source 131 and the amount of current flowing from the second current source 132 may be independently controlled, such that the rate of heat supplied to the system by the heating elements 130 and through resistive heating of the wall 113 of the tubular reactor 110 may be independently controlled.

[0033] In one or more embodiments, at least a portion of the heating element 130 can be heated by passing a second electric current through the heating element 130. The heating element 130 may be capable of achieving a temperature of at least 1000°C, at least 1100°C, at least 1200°C, at least 1300°C, at least 1400°C, at least 1500°C, at least 1600°C, at least 1700°C, at least 1800°C, or even at least 1900°C by electrical resistance heating. For example, without limitation, heating element 130 may have a temperature between 1000°C and 1900°C, 1100°C and 1900°C, 1200°C and 1900°C, 1300°C and 1900°C, 1400°C and 1900°C, 1500°C and 1900°C, 1600°C and 1900°C, 1700°C and 1900°C, 1800°C and 1900°C, 1000°C and 1800°C, 1000°C and 1700°C, 1000°C and 1600°C, 1000°C and 1500°C, 1000°C and 1400°C, 1000°C and 1300°C, 1000°C and 1200°C, 1000°C and 1100°C, or any combination or subset of these values.

[0034] In one or more embodiments, heat may be transferred from the heating element 130 to the wall 113 of the tubular reactor 110. The heat may be transferred by radiation, convection, or a combination thereof. For example, without limitation, heat may be radiated directly from the surface of the heating element 130 to the outer surface 114 of the wall 113 of the tubular reactor 110. Further, heat may be radiated from the heating element 130 to the inner surface 124 of the housing 120. Heat may then be radiated from the inner surface 124 of the housing 120 to the outer surface 114 of the wall 113 of the tubular reactor 110. Additionally, gas contained within the housing may rise by the heating element 130 and fall by the tubular reactor 110, heating the wall of the tubular reactor 110 by convection. In one or more embodiments, the outer surface 114 of the wall 113 of the tubular reactor 110 is spaced apart from the heating element 130. In such embodiments, heat may generally not be transferred from the heating element 130 to the wall 113 of the tubular reactor 110 by conduction.

[0035] As described herein, the walls 113 of the tubular reactor 110 may be heated by electrical resistance heating of the walls 113 of the tubular reactor 110 and by radiative heating from the heating elements 130. In one or more embodiments, the heating elements 130 may provide 10% to 50% of the heat to the walls 113 of the tubular reactor 110. For example, the heating elements 130 may provide 10% to 50%, 20% to 50%, 30% to 50%, 40% to 50%, 10% to 40%, 10% to 30%, 10% to 20%, or any combination or subset of these values ​​of the heat to the walls 113 of the tubular reactor 110.

[0036] In one or more embodiments, the resistive heating of the wall 113 of the tubular reactor 110 can provide 50% to 90% of the heat to the wall 113 of the tubular reactor 110. For example, the resistive heating of the wall 113 of the tubular reactor 110 can provide 50% to 90%, 60% to 90%, 70% to 90%, 80% to 90%, 50% to 80%, 50% to 70%, 50% to 60% of the heat to the wall 113 of the tubular reactor 110, or any combination or subset of these values.

[0037] Without being bound by theory, the use of both electrical resistance heating of the wall 113 of the tubular reactor 110 and radiative heating of the wall 113 from the heating elements 130 may provide several advantages compared to systems that use only radiative heating of the wall 113 or only resistive heating of the wall 113. For example, the use of both radiative and resistive heating of the wall 113 may provide a uniform temperature profile in the wall 113 of the tubular reactor 110 in the radial direction, which may reduce material stresses in the wall 113 of the tubular reactor 110 while the reactor 110 is at operating temperature. Additionally, the uniform temperature profile may allow electrical current to pass more uniformly through the wall 113 of the tubular reactor 110, which may prevent the formation of hot spots in the wall 113 of the tubular reactor 110, which may result in uneven heating of hydrocarbons passing through the tubular reactor.

[0038] Furthermore, without being bound by theory, the use of both radiative and resistive heating of the walls 113 of the tubular reactor 110 may allow the system to have greater operational flexibility, particularly with regard to shifting the heating scheme during different operational phases. For example, during reactor startup, radiative heating can be used to raise the reactor tubes to a temperature where resistive heating is more efficient. This can reduce the amount of energy required to start up the reactor system 100. During steady-state operation of the reactor system 100, resistive heating of the tubular reactor walls may be the primary heat source, and radiative heating may be used to reduce heat loss from the tubular reactor walls 113. Radiative heating can also compensate for heat loss from the sidewalls 123. Furthermore, the use of both radiative and resistive heating allows the reactor to enter a "hot standby" operating mode, where radiative heating is used to maintain the reactor temperature near the operating temperature while resistive heating of the tubes is turned off. This operating mode may be useful in situations where no reaction is currently occurring in the reactor, but complete shutdown of the reactor system 100 is undesirable. Specifically, hot standby mode can prevent the energy losses associated with a complete shutdown of reactor system 100 when a relatively short outage is desired.

[0039] Furthermore, without being bound by theory, the use of both radiative and resistive heating of the walls 113 of the tubular reactor 110 may distribute the heating load across multiple heating elements. Specifically, the heating elements 130 may provide radiative heating to the walls 113 of the tubular reactor 110, and resistive heating of the walls 113 themselves may provide heat to the walls 113 of the tubular reactor. Because neither radiative nor resistive heating provides all of the heat to the reactor system 100, the reactor system 100 may be able to operate with a reduced number of heating elements 130 compared to conventional systems. Furthermore, because neither heating mechanism is responsible for providing all of the heat to the reactor system 100, a wider range of materials may be used for the heating elements 130 and the walls 113 of the tubular reactor 110. Thus, less specialized materials may be suitable for the heating elements 130 and walls 113 of the tubular reactor 110. Less specialized materials may be suitable because the maximum system temperature may be lower than that of conventional combustion-fired furnaces, and having both radiant and resistive heating provides a larger surface area to provide the required heat flux, reducing thermal stresses on the heating element 130 and extending material life. For example, without limitation, less specialized materials for the heating element 130 may include nickel chromium (NiCr 80 / 20), nickel chromium (NiCr 70 / 30) (both capable of operating at temperatures above 1100°C), as well as ferritic iron-chromium-aluminum alloy (FeCrAl) (capable of operating temperatures of 1400°C, has good electrical resistivity, and is very resistant to oxidation).

[0040] Also, without being bound by theory, the use of both radiative and resistive heating of the walls 113 of the tubular reactors 110 may allow for greater flexibility in the placement of the tubular reactors 110 and the heating elements 130 within the enclosure 120. For example, without limitation, the density of the tubular reactors 110 within the enclosure 120 may be increased compared to a reactor system that relies solely on radiative heating. This may be possible because the heating elements 130 contribute only a portion of the heat to the reactor system 100, and the resistive heating of the walls 113 of the tubular reactors 110 themselves also contributes heat to the reactor system 100. If each tubular reactor 110 could provide a portion of the required heat through resistive heating, the system may be able to accommodate more tubular reactors 110. Thus, it may be possible to increase the density of the tubular reactors 110 within the enclosure 120 when both radiative and resistive heating are used.

[0041] Furthermore, without being bound by theory, the use of both radiant and resistive heating of the wall 113 of the tubular reactor 110 may allow for independent control of the heating mechanisms, which may enable the operational flexibility discussed above. Additionally, independent control of the heating mechanisms may allow for multiple heating zones to be formed within the enclosure. Without being bound by theory, the use of multiple heating zones may allow for tighter control of the temperature distribution within the enclosure. Additionally, the use of multiple heating zones may improve the overall reliability and run time of the system if the multiple heating zones are designed to compensate for the loss of a heating zone if one zone fails.

[0042] In one or more embodiments, a method for processing a chemical includes passing a hydrocarbon feed stream 102 through a tubular reactor 110, reacting at least a portion of the hydrocarbon feed stream 102 in the tubular reactor 110 to form a product stream 104, and passing the product stream 104 through an outlet 112 of the tubular reactor 110. It should be noted that reacting the hydrocarbon feed stream 102 to form the product stream 104 may include performing any endothermic reaction. In some embodiments, the endothermic reaction may be a steam cracking reaction, a steam reforming reaction, or a hydrotreating reaction. However, it should be noted that the methods for processing chemicals described herein are not necessarily limited to such reactions.

[0043] In one or more embodiments, the reaction may be a steam cracking reaction. However, the described embodiments may have applicability to a wide range of chemical processes. As described herein, a "steam cracking reaction" refers to the thermal decomposition of hydrocarbons in the presence of steam to produce products such as hydrogen, olefins, and aromatic hydrocarbons. Without being bound by theory, the thermal cracking reaction of hydrocarbons follows a free radical mechanism that requires high temperatures. Steam can act as a diluent to reduce the partial pressure of the hydrocarbons, thereby improving selectivity by promoting higher yields of light olefins.

[0044] In one or more embodiments, the hydrocarbon feed stream 102 can comprise at least one of methane, ethane, propane, and butane. In some aspects, the hydrocarbon feed stream 102 can comprise naphtha or vacuum gas oil. In some embodiments, the hydrocarbon feed stream 102 can comprise C1-C5 hydrocarbons, C1-C6 hydrocarbons, C1-C7 hydrocarbons, C2-C5 hydrocarbons, C3-C6 hydrocarbons, C4-C5 hydrocarbons, C6-C7 hydrocarbons, C7-C8 hydrocarbons, C8-C9 hydrocarbons, C9-C10 hydrocarbons, C10-C12 hydrocarbons, C10-C14 hydrocarbons, C10-C16 hydrocarbons, C10-C18 ... 20 Hydrocarbons, or even C1-C 50 In some embodiments, the hydrocarbon feed stream 102 may further comprise water or steam (H2O), CO2, CO, N2, CO, CO2, H2, or combinations thereof.

[0045] In one or more embodiments, the product stream 104 may include at least one of hydrogen, olefins, and aromatic hydrocarbons. The product stream 104 may include olefins such as ethylene, propylene, 1-butene, 2-butene, isobutylene, 1-pentene, 2-pentene, 2-methyl-1-butene, 3-methyl-1-butene, 2-methyl-2-butene, or combinations thereof. In one or more embodiments, the product stream may include at least one of C2 to C6 olefins. 10 Olefins, C2-C 20 Olefins, or even C2-C 50 In one or more embodiments, the product stream 104 may include aromatic hydrocarbons, such as benzene and its derivatives. The product stream 104 may include benzene, toluene, ethylbenzene, o-xylene, p-xylene, m-xylene, mesitylene, durene, 2-phenylhexane, biphenyl, or combinations thereof.

[0046] In one or more embodiments, product stream 104 may comprise greater than 20 wt%, greater than 25 wt%, greater than 30 wt%, greater than 35 wt%, or greater than 40 wt% olefins, aromatic hydrocarbons, or combinations thereof. For example, without limitation, product stream 104 may comprise 20% to 100% by weight, 30% to 100% by weight, 40% to 100% by weight, 50% to 100% by weight, 60% to 100% by weight, 70% to 100% by weight, 80% to 100% by weight, 90% to 100% by weight, 20% to 90% by weight, 20% to 80% by weight, 20% to 70% by weight, 20% to 60% by weight, 20% to 50% by weight, 20% to 40% by weight, 20% to 30% by weight, or any combination or subset of these ranges of olefins, aromatic hydrocarbons, or combinations thereof.

[0047] In one or more embodiments, the methods for processing chemicals described herein may further include preheating the hydrocarbon feed stream 102. Preheating the hydrocarbon feed stream 102 may occur before passing the hydrocarbon feed stream 102 through the inlet 111 of the tubular reactor 110. In one or more embodiments, preheating the hydrocarbon feed stream 102 may include passing the hydrocarbon feed stream 102 through a heat exchanger 141. In one or more embodiments, the hydrocarbon feed stream 102 may be passed through multiple heat exchangers in parallel, in series, or a combination of both. The heat exchanger 141 may be any suitable heat exchanger, including, but not limited to, a shell-and-tube heat exchanger. Preheating the hydrocarbon feed stream 102 may increase the temperature of the hydrocarbon feed stream 102 to a temperature of 300° C., 400° C., 500° C., or even 600° C. In one or more embodiments, the temperature of the hydrocarbon feed stream 102 exiting the heat exchanger 141 may be lower than the temperature of the wall 113 of the tubular reactor 110.

[0048] In one or more embodiments, the methods of processing chemicals described herein may further include cooling the product stream 104 in a heat exchanger 142. The heat exchanger 142 may cool the product stream 104 below a reaction temperature. Cooling the product stream 104 below a reaction temperature may prevent further reaction or conversion of the product stream 104. In one or more embodiments, the heat exchanger 142 may cool the product stream 104 to a temperature below 1200°C, below 1000°C, below 800°C, below 600°C, or even below 500°C. In one or more embodiments, the heat exchanger 142 may comprise a quench exchanger or any other suitable heat exchanger. In some embodiments, heat removed from the product stream 104 may be used to heat the hydrocarbon feed stream 102. In one or more embodiments, the cooling of the product stream 104 may be performed with multiple heat exchangers in parallel, series, or a combination of both.

[0049] It should be noted that the method steps described herein should not be construed as requiring that the steps be performed in a particular order unless otherwise specified. For example, without limitation, in the methods of processing chemicals described herein, the method steps of passing a first current through at least a portion of the wall of the tubular reactor to heat at least a portion of the wall of the tubular reactor and passing a second current through a heating element to heat at least a portion of the heating element do not necessarily have to be performed in any particular order, and it is contemplated that claims reciting these method steps should not be construed as requiring them in any particular order. In one or more embodiments described herein, it is contemplated that the method steps of passing a first current through at least a portion of the wall of the tubular reactor and passing a second current through a heating element can be performed at any time during the methods of processing chemicals described herein. In particular, such process steps may occur before, during, and after passing the hydrocarbon feed stream through the inlet of the tubular reactor, before, during, and after reacting the hydrocarbon feed stream to form a product stream, and before, during, and after the product stream is passed from the tubular reactor.

[0050] It should be noted that one or more of the following claims utilize the term "wherein" as a transitional phrase. For purposes of defining the art, it should be noted that this term is introduced in the claims as an open-ended transitional phrase used to introduce the recitation of a series of features of a structure, and should be interpreted in a similar manner to the more commonly used open-ended preamble term "comprising."

[0051] It should be understood that when a first component is described as "comprising" a second component, in some embodiments it is contemplated that the first component "consists of" or "consists essentially of" that second component. It should further be understood that when a first component is described as "comprising" a second component, in some embodiments it is contemplated that the first component comprises at least 10%, at least 20%, at least 30%, at least 40%, at least 50%, at least 60%, at least 70%, at least 80%, at least 90%, at least 95%, or even at least 99% of that second component (where % can be by weight or mole %).

[0052] Additionally, the term "consisting essentially of" is used in this disclosure to refer to quantitative values ​​that do not materially affect the basic and novel characteristics of the disclosure. For example, a chemical composition "consisting essentially of" a particular chemical component or group of chemical components should be understood to mean that the composition contains at least about 99.5% of that particular chemical component or group of chemical components.

[0053] The subject matter of the present disclosure has been described in detail with reference to specific embodiments. It should be understood that any detailed description of an element or feature of an embodiment does not necessarily mean that the element or feature is essential to the particular embodiment or any other embodiment. Furthermore, it will be apparent to those skilled in the art that various modifications and variations can be made to the described embodiments without departing from the spirit and scope of the claimed subject matter.

Claims

1. 1. A method for treating a chemical, comprising: passing a hydrocarbon feed stream through an inlet of a tubular reactor; the tubular reactor comprises the inlet, the outlet, and a wall extending from at least the inlet to the outlet; the tubular reactor is at least partially disposed within an enclosure; the housing having a first end, a second end, and at least one sidewall extending from the first end to the second end; passing a hydrocarbon feed stream through the housing, the housing comprising at least one heating element disposed between an inner surface of the side wall of the housing and an outer surface of the wall of the tubular reactor; Passing a first current through at least a portion of the wall of the tubular reactor to heat at least a portion of the wall of the tubular reactor, wherein heating the wall of the tubular reactor provides 50% to 90% of the heat to the wall of the tubular reactor; passing a second current through the heating element to heat at least a portion of the heating element such that heat is transferred from the heating element to the wall of the tubular reactor, wherein the at least one heating element provides 10% to 50% of the heat to the wall of the tubular reactor; reacting at least a portion of said hydrocarbon feed stream in said tubular reactor to form a product stream; and passing the product stream through the outlet of the tubular reactor.

2. 10. The method of claim 1, wherein the heating element is spaced from the exterior surface of the wall of the tubular reactor.

3. 3. The method of claim 1, wherein the sidewall of the housing is spaced from the outer surface of the wall of the tubular reactor.

4. 4. The process of any one of claims 1 to 3, wherein the cross-sectional area of ​​the tubular reactor perpendicular to the bulk flow of the hydrocarbon feed stream through the tubular reactor is substantially constant from the inlet of the tubular reactor to the outlet of the tubular reactor.

5. 5. The method according to any one of claims 1 to 4, wherein 2 to 50 tubular reactors according to claim 1 are at least partially arranged within the enclosure.

6. 6. The method of claim 5, wherein the tubular reactors are connected to an inlet manifold for fluidly connecting the inlets of each tubular reactor, and the tubular reactors are connected to an outlet manifold for fluidly connecting the outlets of each tubular reactor.

7. The heating element is made of NiCr, SiC, MoSi ２ 7. The method of claim 1, wherein the metal oxide comprises FeCrAl, graphite, or FeCrAl.

8. The method of any one of claims 1 to 7, wherein the first current, the second current, or both, comprise an alternating current.

9. The method of any one of claims 1 to 7, wherein the first current, the second current, or both comprise direct current.

10. The method of any one of claims 1 to 9, wherein the hydrocarbon feed stream comprises one or more of ethane, propane, butane, naphtha, and vacuum gas oil.

11. 11. The process of any one of claims 1 to 10, wherein reacting the hydrocarbon feed stream comprises steam cracking at least a portion of the hydrocarbon feed stream, and wherein the product stream comprises one or more olefins.

12. 1. A reactor system comprising: a tubular reactor comprising an inlet, an outlet, and a wall extending at least from the inlet to the outlet, the wall of the tubular reactor being operatively connected to a first current source such that at least a portion of the tubular reactor is heated when a first current is passed through the tubular reactor; A housing, a first end, a second end, and at least one sidewall extending from the first end to the second end; a housing comprising at least one heating element disposed between an inner surface of the side wall of the housing and an outer surface of the wall of the tubular reactor, the at least one heating element being connected to a second current source; the tubular reactor is at least partially disposed within the housing such that the heating element is operable to heat at least a portion of the tubular reactor when the second current is passed through the heating element.

13. 13. The reactor system of claim 12, wherein the heating element is spaced from the outer surface of the wall of the tubular reactor and the sidewall of the housing is spaced from the outer surface of the wall of the tubular reactor.

14. 14. The reactor system according to claim 12 or 13, wherein 2 to 50 tubular reactors according to claim 12 are at least partially arranged in an enclosure.

15. The heating element is made of NiCr, SiC, MoSi ２ , graphite, or FeCrAl.

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