Panel-shaped resistive heating elements for electrically heated furnaces

Abstract

Apparatuses are described for electrically heated chemical processes, including, but not limited to, steam cracking and steam reforming. The apparatus may generally include a furnace having one or more process tubes extending though an interior cavity of the furnace. The apparatus may further include one or more panels secured and disposed within the interior cavity, the panels including an electrically resistive material having a plurality of apertures defined therein. Also provided is a system and method for hydrocarbon conversion using the apparatus.

Description

PANEL-SHAPED RESISTIVE HEATING ELEMENTSFOR ELECTRICALLY HEATED FURNACESFIELD OF DISCLOSURE

[0001] The present disclosure relates to apparatuses, systems and methods for generating thermal energy for the conversion of hydrocarbons.BACKGROUND

[0002] High temperature furnaces are useful for various applications, including, but not limited to chemical processes. In particular, high temperature furnaces have been used in steam cracking, steam methane reforming (SMR), reforming for ammonia, dehydrogenation, tar cracking, or similar applications. Such processes and furnaces for heating such processes traditionally rely on use of combustion. To meet new sustainability and carbon dioxide emission reduction requirements it is desirable to replace such fired heaters.

[0003] Recent developments have included heaters and furnaces powered by electricity, preferably renewable electricity, to provide heat to the processes above. One exemplary construction of heaters includes an impedance heater. Typically, the impedance heater will apply an electrical current directly to a process tube or vessel to heat the process fluid flowing inside. In some types of impedance heated furnace designs, the impedance element is a separate metal structure to which current is applied. However, existing impedance technologies operate at low voltages, usually less than 100 volts, requiring large amounts of electrical current to achieve the desired heat flux and temperatures necessary for steam cracking and steam methane reforming.

[0004] Another type of heater includes a conductive heating element, often in the form of a metal wire or metal ribbon. Because the material making up such heating element exhibits poor mechanical properties, this type of construction necessitates a furnace wall, including full mechanical support and insulation, for every heating surface. Accordingly, such designs are restricted to a single row or at most a double row of process tubes in which the process feed can flow. In contrast, conventional gas-fired furnaces may have floor and ceiling burners, allowing for a more compact structure with multiple rows of process tubes.

[0005] Furthermore, because of the geometry of the metal wire and metal ribbon, the amount of heating element surface area provided by this design within the furnace is limited due to the need for space for inclusion of the mechanical supports. To increase the amount of heatingelement surface area, while also increasing the total circuit resistance to operate at practical voltages, the wire or ribbon is bended in a serpentine fashion. However, minimum bend radii of the metallic wire or ribbon impose a geometrical constraint on the fraction of resistive heating area provided making it challenging to meet the heat fluxes needed for industrial steam cracking and steam methane reforming processes. Finally, the lifetime of the wire or ribbon heating element is limited since, in general, their maximum operating temperature cannot exceed 1300°C.

[0006] For electrically powered processes, the inventors have identified apparatuses, systems and methods for heating chemical processes using panels that are able to achieve desired heat fluxes at lower temperatures than those for conventional wire or ribbon heating elements.SUMMARY

[0007] In a first embodiment of the present disclosure, provided herein is an apparatus for hydrocarbon conversion, the apparatus includes a furnace and one or more panels. The furnace has an interior cavity and one or more process tubes extending through the interior cavity of the furnace. The one or more tubes are operable to receive a process vapor or fluid at an upstream end of the furnace and discharge a product stream at a downstream end of the furnace. The process vapor or fluid includes a hydrocarbon. The one or more panels are secured and disposed within the interior cavity of the furnace and are operable to receive electrical power from a power source. The one or more panels include an electrically resistive material that has a plurality of apertures defined therein. The electrically resistive material is operable to generate heat on the flow of an electrical current there through to heat the interior cavity of the furnace. The product stream includes at least a C2- C4 alkene, syngas, or a combination thereof. In some embodiments, the apparatus is easily scaled and may have a power output of 1 megawatt (MW) or greater, for example, at least 2 MW, at least 3 MW, at least 5 MW, at least 10 MW, at least 20 MW, at least 50 MW, at least 75 MW, at least 100 MW, at least 250 MW, at least 500 MW or up to 1 GW.

[0008] In another embodiment, provided herein is a system for hydrocarbon conversion including a process vapor or fluid and any implementation of the first embodiment (apparatus). The process vapor or fluid includes a hydrocarbon. The hydrocarbon can include natural gas, methane, naphtha, liquefied petroleum gas, ethane, propane, butane, as well as other hydrocarbon feedstocks, including, but not limited to, gas condensate, gas oil, diesel, jet fuel, gas-to-liquid fuel and bio feedstock, as well as any combinations thereof.

[0009] In still another embodiment, provided herein is a method for hydrocarbon conversion. The method includes flowing a process vapor or fluid through one or more process tubes extending through the interior cavity of a furnace of an apparatus (an implementation of the first embodiment). The process vapor or fluid includes a hydrocarbon. The apparatus includes one or more panels secured and disposed within the interior cavity of the furnace and electrically connected to a power source. The one or more panels include an electrically resistive material having apertures defined therein. The method includes applying, by the one or more panels, heat to external surfaces of the tubes to convert at least a portion of the hydrocarbon flowing there through to a product. The product can include at least a C2-C4 alkene, syngas, or a combination thereof. The method further includes discharging a product stream comprising the product from the furnace. In certain embodiments, the one or more process tubes of the furnace may be operable to receive the process vapor or fluid associated with a process selected from steam cracking, steam methane reforming, reforming for ammonia, dehydrogenation, and tar cracking. The electrical power from the power source may correspond to a voltage greater than 250 volts, or greater than 500 volts, or greater than 1000 volts, and or even greater than 2000 volts.

[0010] Still other aspects and advantages of these exemplary embodiments and other embodiments are discussed in detail herein. Moreover, it is to be understood that both the foregoing information and the following detailed description provide merely illustrative examples of various aspects and embodiments and are intended to provide an overview or framework for understanding the nature and character of the claimed aspects and embodiments. Accordingly, these and other objects, along with advantages and features of the present disclosure, will become apparent through reference to the following description and the accompanying drawings. Furthermore, it is to be understood that the features of the various embodiments described herein are not mutually exclusive and may exist in various combinations and permutations.

[0011] Some details associated with the aspects of the present disclosure are described above, and others are described below. Other implementations, advantages, and features of the present disclosure will become apparent after review of the entire application, including the Brief Description of the Drawings, Detailed Description, and the Claims.BRIEF DESCRIPTION OF THE DRAWINGS

[0012] The accompanying drawings, which are included to provide a further understanding of the embodiments of the present disclosure, are incorporated in and constitute a part of thisspecification, illustrate embodiments of the present disclosure, and together with the detailed description, serve to explain principles of the embodiments discussed herein. No attempt is made to show structural details of this disclosure in more detail than may be necessary for a fundamental understanding of the embodiments discussed herein and the various ways in which they may be practiced. According to common practice, the various features of the drawings discussed below are not necessarily drawn to scale. Dimensions of various features and elements in the drawings may be expanded or reduced to more clearly illustrate embodiments of the disclosure.

[0013] FIG. 1 depicts block flow diagram of a generalized methanol synthesis plant or process.

[0014] FIG. 2 depicts a block diagram of an apparatus that may be operable for use in the syngas synthesis section of the plant or process of FIG. 1.

[0015] FIG. 3 depicts a block flow diagram of a generalized steam cracking plant or process.

[0016] FIG. 4 depicts a block flow diagram of the pyrolysis reaction section of the plant or process of FIG. 3.

[0017] FIG. 5A depicts a front cross-sectional view of an example of an apparatus configuration for use in the syngas synthesis section of FIG. 1 or the pyrolysis reaction section of FIG. 3.

[0018] FIG. 5B depicts a cutaway view of a panel facing the reactor tubes of FIG. 5 A.

[0019] FIG. 5C depicts a top view of an embodiment of the apparatus having multiple rows of reactor tubes and panels.

[0020] FIG 5D depicts a cutaway view of a plurality of panels spanning the height of the wall being offset vertically above one another and facing the reactor tubes of FIG. 5 A.

[0021] FIGs. 6A, 6B and 6C depict side views of panels of the apparatus of FIG. 5A according to embodiments of the present disclosure.

[0022] FIGs. 7A and 7B depict top and side views of the panel of FIGs. 6A, 6B and 6C secured to an inner wall of a furnace according to an embodiment of the present disclosure.

[0023] FIGs. 8A, 8B, 8C and 8D depict side views showing mechanically reinforced panels according to embodiments of the present disclosure.

[0024] FIG. 9 depicts the electrical current in a comparative panel.

[0025] FIG. 10 depicts the ohmic loss near the surface of the comparative panel of FIG. 9.

[0026] FIG. 11 depicts the magnitude in current flow in the comparative panel of FIG. 9.

[0027] FIGs. 12(a)-12(e) depict the ohmic loss near the surface of panels according to the present disclosure.

[0028] FIG. 13 depicts the temperature profile for the comparative panel of FIG. 9 and process tubes radiatively heated by the panel.

[0029] FIG. 14 depicts the temperature profile for the comparative panel of FIG. 13 by itself.

[0030] FIG. 15 depicts the temperature profile for the process tubes of FIG. 13 by themselves.

[0031] FIG. 16 depicts the temperature profile for a panel according to the present disclosure and process tubes radiatively heated by the panel.

[0032] FIG. 17 depicts the temperature profile for the panel of FIG. 16 by itself.

[0033] FIG. 18 depicts the temperature profile for the process tubes of FIG. 16.

[0034] FIG. 19 depicts a panel according to the present disclosure with identified locations with disclosed performance.DETAILED DESCRIPTION

[0035] The drawings include like numerals to indicate like parts throughout the several views, the following description provides an enabling teaching of exemplary embodiments, and those skilled in the relevant art will recognize that many changes may be made to the embodiments described. It also will be apparent that some of the desired benefits of the embodiments described may be obtained by selecting some of the features of the embodiments without utilizing other features. Accordingly, those skilled in the art will recognize that many modifications and adaptations to the embodiments described are possible and may even be desirable in certain circumstances. Thus, the following description is provided as illustrative of the principles of the embodiments and not in limitation thereof.

[0036] The phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. As used herein, the term “plurality” refers to two or more items or components. The terms “comprising,” “including,” “carrying,” “having,” “containing,” and “involving,” whether in the written description or the claims and the like, are open-ended terms, i.e., to mean “including but not limited to,” unless otherwise stated. Thus, the use of such terms encompasses the items listed thereafter, and equivalents thereof, as well as additional items. The transitional phrases “consisting of’ and “consisting essentially of,” are closed or semi-closed transitional phrases, respectively, with respect to any claims. Use of ordinal terms such as “first,” “second,” “third,” and the like in the claims to modify a claimelement does not by itself connote any priority, precedence, or order of one claim element over another or the temporal order in which acts of a method are performed, but are used merely as labels to distinguish one claim element having a certain name from another element having a same name (but for use of the ordinal term) to distinguish claim elements.

[0037] In addition, while reference may be made to quantitative measures, values, geometric relationships or the like, unless otherwise stated, any one or more if not all of these may be absolute or approximate to account for acceptable variations that may occur, such as those due to manufacturing or engineering tolerances or the like.

[0038] The term “coupled” includes connected, although not necessarily directly, and not necessarily mechanically; two items that are “coupled” may be unitary with each other. The terms “a” and “an” are defined as one or more unless this disclosure explicitly requires otherwise. The term “substantially” is defined as largely but not necessarily wholly what is specified (and includes what is specified; e.g., substantially 90 degrees includes 90 degrees and substantially parallel includes parallel), as understood by a person of ordinary skill in the art.

[0039] Further, an apparatus or system that is configured in a certain way is configured in at least that way, but it can also be configured in other ways than those specifically described.

[0040] Any embodiment of any of the present apparatuses, systems and methods can consist of or consist essentially of - rather than comprise / include / contain / have - any of the described steps, elements, and / or features. Thus, in any of the claims, the term “consisting of’ or “consisting essentially of’ can be substituted for any of the open-ended linking verbs recited above, in order to change the scope of a given claim from what it would otherwise be using the open-ended linking verb.

[0041] The term “hydrocarbon conversion process” is used to include an endothermic process designed to break down, crack, or convert hydrocarbons. Examples include, but are not limited to, pyrolysis based processes such as steam cracking of lower alkanes into alkenes and catalyst mediated processes such as methane reforming (methane into carbon monoxide and hydrogen).

[0042] The term “hydrocarbon conversion” is meant to include conversion of hydrocarbons that are endothermic in nature and require temperatures exceeding 500°C, such as but not limited to, the conversion of alkanes into alkenes and the conversion of methane into carbon monoxide and hydrogen.

[0043] The terms “downstream” and “upstream” are used in relation to an overall flow direction of the process vapor or fluid flowing through the furnace as described herein, withthe process vapor or fluid accepted at the upstream end (or inlet) of the furnace and a product stream discharged at a downstream end (or outlet) of the furnace.

[0044] The term “C2-C4 alkene” is used to include ethylene, propylene, alpha-butylene, cis-2 -butene, trans-2-butene, isobutylene, or any combination thereof.

[0045] The term “furnace” includes, but is not limited to, reactors having an enclosed space or chamber (interior cavity) in which a hydrocarbon conversion reaction takes place. Reactor types include, but are not limited to, coils used in steam cracking processes and reactor tubes used in steam methane reformers. Coils in steam cracking furnaces are formed from an assembly of furnace straight tubes, U-bends, wyes, and elbows that results in a serpentine conduit that extends from the point of entry to the point of exit of the furnace. Steam cracking furnaces may include one or more coils that may be connected by wyes or other shaped headers at their corresponding upstream and downstream ends.

[0046] The term “panel” means an element with a flat shape, i.e. having a small thickness as compared to its length and width. The panel can be in the form of a plate or a sheet made of a single material or a composite assembly. In the latter case, the panel may be a stack of a plurality of layers of the same material or different materials. In the framework of this disclosure, the panel will have been previously shaped by means of any known shaping process including, by way of non-restricting examples, bending, forming, stamping, molding and 3D printing. The panel may be shaped into the form of any shape including, but not limited to, square, hexagonal, triangular, rectangular, circular, elliptical, or diamond shape.

[0047] The term “electrically resistive material” means a material or structure having a resistance typically in the range of, but not limited to, 0. 1-10 Ohms such that electrical current is able to pass through the material or structure, but where the material or structure generates heat as a result of the electrical current flow. Electrically resistive materials may include, but are not limited to, doped ceramics, electrically “conductive” ceramics, carbon, graphite, metals, metal alloys and composite materials made of a ceramic material and a metallic material. Such composite materials may comprise doped or undoped ceramics. Non-limiting examples of ceramics include zirconia, chromia, titanium dioxide, magnesia, alumina, silica, niobium oxide, and molybdenum disilicide. Non-limiting examples of doped ceramics include doped silicon carbides, magnesia doped with chromium, alumina doped with chromium, chromia doped with carbon, chromia doped with magnesium. Non-limiting examples of metals include iron, chromium, tungsten, titanium, zirconium, tantalum, platinum, gold and silver. Nonlimiting examples of metal alloys include stainless steel, constantan, nickel-containing alloys,cobalt-containing alloys, chromium-containing alloys, aluminum-containing alloys, titanium- containing alloys, zirconium-containing alloys, hafnium-containing alloys, niobium- containing alloys, molybdenum-containing alloys, tantalum-containing alloys, tungsten- containing alloys, tin-containing alloys, gallium-containing alloys, manganese-containing alloys, and iron-containing alloys, nickel-based superalloys, iron-based superalloys, ironaluminum base alloys, iron-manganese-aluminum base alloys, platinum / rhodium alloy, nickel / chrome alloy (e.g., Nichrome), iron / chrome alloy, FeCrAl, NiFe, NiCrFe and CuNi.

[0048] The term “electrically insulative material” includes at least one dielectric material, such as one or more of at least one dielectric oxide material (e.g., one or more of a silicon oxide (SiOx), phosphosilicate glass, borosilicate glass, borophosphosilicate glass, fluorosilicate glass, an aluminum oxide (A1OX), a hafnium oxide (HfOx), a niobium oxide (NbOx), a titanium oxide (TiOx), a zirconium oxide (ZrOx), a tantalum oxide (TaOx), and a magnesium oxide (MgOx)), at least one dielectric nitride material (e.g., a silicon nitride (SiNy)), at least one dielectric oxynitride material (e.g., a silicon oxynitride (SiOxNy)), or at least one dielectric carboxynitride material (e.g., a silicon carboxynitride (SiOxCzNy)). In one embodiment, the electrically insulative material may be AI2O3 or SiOxCzNy. Formulae including one or more of “x”, “y”, and “z” herein (e.g., SiOx, A1OX, HfOx, NbOx, TiOx, SiNy, SiOxNy, SiOxCzNy) represent a material that contains an average ratio of “x” atoms of one element, “y” atoms of another element, and “z” atoms of an additional element (if any) for every one atom of another element (e.g., Si, Al, Hf, Nb, Ti). As the formulae are representative of relative atomic ratios and not strict chemical structure, the dielectric material may comprise one or more stoichiometric compounds and / or one or more non-stoichiometric compounds, and values of “x”, “y”, and “z” (if any) may be integers or may be non-integers. As used herein, the term “non-stoichiometric compound” means and includes a chemical compound with an elemental composition that cannot be represented by a ratio of well-defined natural numbers and is in violation of the law of definite proportions.

[0049] The term “aperture” means a hole, slot, channel or other opening that extends directly and completely through the thickness of the material. The aperture can have rectangular, elliptical, round, and / or other shapes in regular and / or irregular patterns.

[0050] According to a first embodiment, provided herein is an apparatus for hydrocarbon conversion, the apparatus including (i) a furnace having an interior cavity and one or more process tubes extending through the interior cavity of the furnace and (ii) one or more panels secured and disposed within the interior cavity of the furnace, the one or more panels includingan electrically resistive material having a plurality of apertures defined therein. The process tubes are operable to receive a feed stream (e.g., process vapor or fluid) comprising a hydrocarbon at an upstream end of the furnace and discharge a product stream at a downstream end of the furnace. The one or more panels are operable to receive electrical power, for example via one or more power lines via one or more terminals. The electrical power received may be alternating current (AC) or direct current (DC). The one or more panels are operable to convert electricity into heat and heat the interior cavity of the furnace to promote conversion of at least a portion of the hydrocarbon to a product as the process vapor or fluid moves from the upstream end of the furnace to the downstream end of the furnace. The product of the conversion reaction is discharged at the downstream end as part of the product stream. The term “product” in this context may include multiple species that are formed during the conversion reaction. Also provided herein is a system including a feed stream (e.g., process vapor or fluid) comprising a hydrocarbon and the apparatus of the first embodiment and a method for hydrocarbon conversion including passing the feed stream (e.g., process vapor or fluid) comprising a hydrocarbon through the apparatus of the first embodiment.

[0051] Referring now to the drawings, and more particularly to FIG. 1, shown there is a block flow diagram of an example of a generalized methanol synthesis plant (in which the apparatuses of the first embodiment may be used). The methanol synthesis plant generally includes one or more of the following process sections for converting a feed stream 5 into a methanol product stream 45 (and optionally one or more byproduct streams 41): a feed pretreating section 10, a syngas synthesis section 20, a methanol synthesis section 30, a methanol purification section 40, or a combination thereof. Such sections will be described briefly in the next few paragraphs.

[0052] As indicated in the methanol synthesis block flow diagram, a feed pretreating section 10 of a methanol synthesis plant is operable to prepare (e.g., remove undesirable components (e.g., sulfur) from, adjust temperature and / or pressure of) a feed 5 for reforming, and providing a pretreated feed 15. In some applications, a methanol synthesis plant of this disclosure does not comprise a feed pretreating section.

[0053] A syngas synthesis section 20 is operable to produce a synthesis gas product 25 from feed 5 or pretreated feed 15. In some implementations, syngas synthesis section 20 is operable to carry out steam reforming of the feed (e.g., of a feed 5 or pretreated feed 15 comprising natural gas) to produce a reformer product comprising carbon monoxide and hydrogen. The syngas synthesis (or “reformer”) product 25 can further comprise carbondioxide (CO2), water, methane (CH4), and / or impurities. For example, for some embodiments of the present apparatus, the one or more process tubes can comprise a steam reforming catalyst to carry out the syngas reaction to produce carbon monoxide and hydrogen.

[0054] A methanol synthesis section 30 is operable to produce methanol from the syngas synthesis product 25 and thus provide a crude methanol stream 35. A methanol purification section 40 is operable to separate a purified methanol product 45 and byproducts 41 from the crude methanol stream 35.

[0055] Referring now to FIG. 2, shown there is a block diagram of an apparatus that may be operable for use in the syngas synthesis (reforming) section 20 of the plant or process of FIG. 1. As shown in FIG. 2, the apparatus generally includes a furnace 100 having an inlet for receiving process vapor or fluid at an upstream end of the furnace and an outlet 108 for discharging a product stream at a downstream end of the furnace. The apparatus also includes one or more panels (not shown) secured and disposed within the interior cavity of the furnace, the panels comprising an electrically resistive material having a plurality of apertures defined therein.

[0056] FIGs. 1 and 2 depict one example of a methanol synthesis system for illustration purposes, but the present apparatus may be used in any of various chemical synthesis systems and processes, particularly in place of furnaces that have historically been powered by direct combustion or fossil fuels.

[0057] Referring now to FIG. 3, shown there is a block flow diagram of an example of a generalized steam cracking plant. The steam cracking plant includes one or more of the following process sections for converting a feed stream 50 into a desired olefin product stream 90: a feed pretreatment section 55, a pyrolysis reaction section 65, a primary fractionation and compression section 75, a product fractionation (separation) and compression section 85, or a combination thereof. Such sections will be described briefly in the next few paragraphs.

[0058] Feed pretreatment section 55 can be configured to adjust the pressure of a feed 50, possibly remove undesirable components from a feed, combine an incoming feed with a stored feed to minimize variations in the feed to the pyrolysis reaction section 65, vaporize the feed 50, and / or preheat the feed 50, to provide a pretreated feed stream 60.

[0059] Pyrolysis reaction section 65 can comprise at least one steam cracker or ‘pyrolysis’ furnace configured to crack hydrocarbons in the presence of steam to produce a cracked gas stream and a transfer line exchanger (TLE) or other heat transfer device to quench (and optionally harvest heat from) the cracked gas stream to provide a cooled cracked stream 70.Conventionally, the furnaces of a steam cracking plant create a high temperature environment by the combustion of fuels such as methane and hydrogen, which produces carbon dioxide emissions. In the present embodiments, the furnace is a radiative electric furnace in which the one or more panels comprising the electrically resistive material provide heat or thermal energy to an interior cavity of the furnace and the process tubes through which the process or fluid flows.

[0060] The primary fractionation and compression section 75 can be operable to provide further heat recovery from and quenching of the cooled cracked gas stream 70, remove one or more components (e.g., fuel oil, hydrogen sulfide, carbon dioxide, water, or a combination thereof) from the cracked gas stream 70, and / or compress the cracked gas stream 70, thus providing a compressed cracked gas stream 80.

[0061] The product fractionation or separation section 85 can be operable to fractionate the compressed cracked gas stream 80, selectively hydrogenate one or more streams produced during the fractionation, and provide one or more olefin (e.g., ethylene, propylene) product streams 90. The product fractionation or separation section 85 may also provide one or more byproduct streams 86, such as, without limitation, a Ci stream, a C2 saturate stream, a C3 saturate stream, a C4 saturate stream, an acetylene stream, a butadiene stream, a 1-butene stream, an isobutylene stream, an aromatics stream, a hydrogen stream, a pyrolysis gasoline stream, and / or a fuel oil stream, or streams comprising a combination of these components. Some of these streams may be recycled to one or more sections of the steam cracking plant. For example, without limitation, the C2, C3, and / or C4 saturate streams may be recycled to one or more of the pyrolysis furnaces of the pyrolysis reaction section 65, hydrogen may be purified (e.g., via a pressure swing adsorption unit (PSA) and a methanation reactor to remove CO) and recycled to a hydrogenation reactor (e.g., a C2, C3, acetylene, or di-olefin hydrogenator) and / or utilized as a fuel source (e.g., via fuel cell). The Ci stream may also be recycled for use as a fuel (e.g., for the production of hydrogen therefrom).

[0062] Referring now to FIG. 4, and as also noted above, the pyrolysis reaction section 65 can comprise at least one steam cracker in which the apparatus may be used. The apparatus is operable to crack hydrocarbons in the presence of steam to produce a cracked gas stream. The steam cracker may further include a quench unit (e.g., a transfer line exchanger (TLE) or other heat transfer device) to quench (and optionally harvest heat from) the cracked gas stream to provide a cooled cracked stream 205. As shown in FIG. 4, the apparatus 100a generally includes a furnace having an inlet 104 at its upstream end for receiving a process vapor or fluidcomprising a hydrocarbon and an outlet 108 at its downstream end for discharging a product stream, with the outlet 108 in fluid communication with a fluid inlet of the quench unit. The apparatus further includes one or more panels (not shown) secured and disposed within the interior cavity of the furnace.

[0063] FIGs. 3 and 4 depict one example of a steam cracking plant for illustration purposes, but the present apparatuses can be used in any of various steam cracking systems and processes.

[0064] FIGS. 5 A and 5B show aspects of an example apparatus 100b configuration that may be used for apparatus 100 or apparatus 100a. FIG. 5 A depicts a side cross-sectional view of apparatus 100b and FIG. 5B depicts a cutaway view showing an inner side of a sidewall of apparatus 100b. As shown, apparatus 100b includes a furnace 112 having a housing that defines an interior cavity 116. The furnace has an upper end 120 and a lower end 124 separated by a height 128. In this configuration, apparatus 100b also includes panel 132a secured and disposed within the interior cavity 116 on a first sidewall 136 and panel 132b secured and disposed within the interior cavity 116 on a second sidewall 140 that is separated from the first sidewall by a width 144. As shown, panel 132b is therefore spaced apart from panel 132a. Although in this configuration, panels 132a, 132b extend along a majority of the height 128 of each of the first and second sidewalls, in other embodiments panels 132a, 132b could extend less than 75% of the height 128 of each of the first and second sidewalls, or less than 50% of the height 128 of each of the first and second sidewalls, or less than 30% of the height 128 of the first and second sidewalls. Furthermore, multiple panels 132a, 132b can be arranged adjacent to one another to extend along a majority, or less than 75%, or less than 50% of the height 128 of each of the first and second sidewalls. Panels 132a, 132b include an electrically resistive material 150 having a plurality of apertures 158 defined therein, electrical connections (not shown) via which electrical power can be supplied to the panels 132a, 132b and securing mechanisms 154 (see FIG. 5C) operable to secure each panel to the sidewall.

[0065] Such panels may be distributed within the interior cavity and across an inner wall of the furnace, such as an inner sidewall or inner end wall, in any configuration. For example, an inner sidewall may comprise a single large panel (see FIG. 5B) that spans substantially the height of the sidewall, a plurality of panels spanning the height of the sidewall by being disposed (e.g., offset) vertically above one another (see FIG. 5D), a plurality of panels that span the width of the side wall disposed (e.g., offset) horizontally next to one another across the width, or a patchwork of panels whose dimensions span neither span the full height nor the full width of the furnace sidewall. In still other embodiments, one or more panels may be disposedon an end wall of the furnace such that the one or more panels are facing perpendicular to a plurality of process tubes. In further embodiments, the one or more panels and process tubes may be arranged in alternating rows such that each side of the panel 132a, 132b radiates heat to process tubes 148 as shown in FIG. 5C. This allows for more compact furnace geometries and multi-tube row geometries as compared to conventional radiative heating element technologies. The panels of the present disclosure are distinct from the conventional wire panels with hangars in that the panel is a unibody structure (i.e., the panel mechanically supports the electrically resistive material). Accordingly, the panel is operable to perform multiple functions.

[0066] As shown in FIG. 5 A, apparatus 100b also includes one or more process tubes or coils (e.g., reactor tubes) 148 which extend through the interior cavity 116 of the furnace from the upper end 120 towards the lower end 124. In the depicted configuration, each process tube 148 has an inlet section, an outlet section, and a medial section 152 between the inlet section and outlet section. For each process tube 148, the inlet section and outlet section extend in a first direction from the upper end 120 of the furnace toward the lower end 124, and the medial section 152 is disposed closer to lower end 124 of the furnace than to the upper end 120. Each tube of the inlet section has a first diameter that may be smaller than a second diameter of the tube of the corresponding outlet section. In this configuration, the tubes of the inlet section and outlet section are each disposed equidistant from the first and second sidewalls 136, 140 to balance the amount of thermal energy process tubes 148 absorb from each of the panels. Various other configurations can include any number of process tubes in any of various symmetric or asymmetric configurations (e.g., with inlets grouped together and outlets grouped together). For example, the process tubes or coils in other configurations of the present furnaces may have any shape, size, or configuration, including any that are used in industrial practice (for example, in steam cracking and steam reforming furnaces). For example, such tubes may extend linearly through the furnace, with inlet and outlet at the same or opposite ends of the furnace. Such tubes may also merge or split within the furnace, and thereby have a different number of inlets than outlets (e.g., a number of inlets that is a multiple of the number of outlets, or a number of outlets that is a multiple of the number of inlets). Tube outside diameters may, for example, fall in a range of from 2 centimeters (cm) to 20 cm (e.g., from 2 cm to 5 cm, from 4 cm to 10 cm). Such tubes may also be oriented or arranged relative to one another in any of various fashions, for example with inlets and outlets alternating, with severalinlets grouped together in one part of the furnace and several outlets grouped together in another part of the furnace, and / or with different symmetric or asymmetric combinations.

[0067] In the depicted example, medial section 152 of each tube 148 extends from a first end at the inlet section to a second end at the corresponding outlet section and defines a change in direction of each tube. In this configuration, the inlet sections and outlet sections are each defined by straight sections of tubing, and medial sections 152 extend between those straight pieces of tubing. The inlet and outlet sections may vary in shape in other configurations. A fluid inlet conduit 104a is in fluid communication with the inlet sections of the process tubes 148, and a fluid outlet tube (not shown) is in fluid communication with the outlet sections of the process tubes, such that fluid flowing into the inlet conduit 104a flows sequentially through the inlet sections of the process tubes 148, the medial sections 152 of the process tubes 148, and the outlet sections of the tubes process 148, to the fluid outlet tube.

[0068] FIG. 5B depicts an inner side of second sidewall 140 (which may be roughly a mirror image of first sidewall 136). As shown for this example, second sidewall 140 extends between a first end wall 156 and a second end wall 160, with the end walls 156, 160 separated from each other by a chamber length 164. For the types of hydrocarbon conversion systems contemplated by the present disclosure, the present furnaces are typically implemented on an industrial scale. For example, interior cavity 116 may have a height 128 of five (5) meters or more (e.g., greater than any one of or between any two of 5, 10, 15, and / or 20 meters); a width 144 of 0.5 meter or more (e.g., greater than any one of or between any two of: 0.5, 1, 2, 3, 4, and / or 5 meters); and a length 164 of one (1) meter or more (e.g., greater than any one of or between any two of: 1, 2, 5, 10, and / or 20 meters).

[0069] FIGs. 6A-6C depict a panel 632 according to an embodiment of the present disclosure. Panel 632 may include a sheet of electrically resistive material 650. Panel 632 may be formed by shaping the sheet of electrically resistive material 610. For example, panel 632 may be cut from the sheet of electrically resistive material 610, for example, by a laser or by a chemical or electrical processor by a high-pressure waterjet. Alternatively, panel 632 may be pre-formed in the desired shape. The sheet 650 of electrically resistive material may have any suitable shape, including, but not limited to, circular, oval, square, triangular, rectangular or polyhedral.

[0070] The sheet of electrically resistive material 650 includes a plurality of apertures 658 defined therein. The plurality of apertures 658 (which define electrically isolated areas in the electrically resistive material) define a plurality of electrically resistive vertical strips 630 inthe electrically resistive material 650 that are operable to radiate heat when an electrical current is flowing through the panel 632 and sheet of electrically resistive material 650. In some embodiments, each of the electrically resistive vertical strips have equal widths w and lengths 1. The width w and length 1 may also be chosen such that the panel 632 has a desired resistance value. In some embodiments, the panel 632 may include at least 2 apertures, or at least 5 apertures, or at least 10 apertures, or at least 15 apertures or at least 20 apertures, or at least 25 apertures or at least 30 apertures. Accordingly, in other embodiments, the panel 632 may include at least 3 electrically resistive vertical strips, or at least 7 electrically resistive vertical strips, or at least 10 electrically resistive vertical strips, or at least 15 electrically resistive vertical strips, or at least 20 electrically resistive vertical strips or at least 25 electrically resistive vertical strips or at least 30 electrically resistive vertical strips.

[0071] In some embodiments, panel 632 may be mechanically and / or electrically reinforced to provide more cross-sectional area (with lower electrical resistance per length) to minimize voltage drop across the width of the panel 632. Additionally, such reinforcement can further provide stiffness to mitigate panel warping. In one embodiment, panel 632 may be reinforced at an upper end and a lower end by plating 634 as shown in FIG. 6B. The plating 634 may be affixed to the upper and lower ends of panel 632 by known methods, such as by welding, high temperature brazing or mold casting. Mechanical reinforcement and / or electrical resistance reduction may also be achieved in desired areas by increasing the panel thickness. In some embodiments, in addition to or in place of plating 634, panel 632 may be mechanically reinforced by one or more electrically resistive horizontal strips 636 positioned between vertically adjacent apertures 658 as shown in FIG. 6C.

[0072] As discussed above, panel 632 may be secured within the interior cavity of the furnace by various securing mechanisms including, but not limited to, mounts, pegs, hooks, brackets, fasteners, clamps, or supports. The securing mechanism may be affixed to an inner wall of the furnace such as a sidewall or end wall. The securing mechanism may be electrically insulative or made of an electrically insulative material. One particular embodiment of a securing mechanism 702 is shown in FIGs. 7A and 7B and includes opposing mounts affixed to a sidewall, each mount 702 having an opening 704 that is shaped and operable to allow a portion of the panel 632 to slide into and out of. Panel 632 may be then be held in place by various ways, such as by inserting electrically insulative spacers into the opening(s) 704.

[0073] According to yet another embodiment, in order to minimize or prevent portions of the electrically resistive material from overheating, additional apertures may be formed nearthe panel ends. In one embodiment, panel 632 can be formed to have one or more side apertures 660a as shown in FIG. 7A. Although two side apertures are shown opposing one another, each of the side apertures 660a may be positioned anywhere along the height of the panel. The side apertures 660a are operable to break the electrical circuit through the resistive vertical channel 630a. In some embodiments, the width of side apertures 660a may be larger than the width of the plurality of apertures 658 for further increasing the mechanical strength of panel 632. In still other embodiments, in order to re-introduce mechanical support across the electrically isolated area created by side aperture 660a, an electrically insulative material 602 may attached to opposing ends of side aperture 660a as shown in FIGs. 8C and 8D. To provide positioning in the support system, metal springs may be used to secure the panel within the electrically insulative holding elements provided the springs do not have any additional contact with an electrically conducting furnace element that would allow electrical current flow through the spring. In addition, in still further embodiments, an electrically insulative material 602 may be also be attached to one or more comers of the panel to provide support and electrical isolation if desired.

[0074] According to another embodiment, the present disclosure provides a system for hydrocarbon conversion. The furnace has an interior cavity and one or more process tubes extending through the interior cavity. The process tubes receive the process vapor or fluid at an upstream end of the furnace and discharge a product stream at a downstream end of the furnace. The process vapor or fluid includes a hydrocarbon. The panels are disposed within the interior cavity of the furnace and secured to an inner wall of the furnace by a securing mechanism, for example, mounts, brackets, fasteners, clamps, or supports. The panel includes an electrically resistive material having a plurality of apertures defined therein. The panel is electrically coupled to a power source and receives electrical power from a power source and converts the electrical power to heat to heat an external surface of the process tube to convert the hydrocarbon (from the feed stream) and produce a product that is discharged as part of the product stream.

[0075] In some embodiments, the panel is operable to provide heat to the process vapor or flowing within the process tube such that the process vapor or fluid has a temperature from about 115°C to about 1200°C, from about 450°C to about 1100°C, or from about 650°C to about 1000°C. In some embodiments, the process vapor or fluid has a residence time in the furnace from about 0.02 s to about 4.5 s, from about 0.05 s to about 4.5 s, from about 0.1 s to about 2.5 s, or from about 0.1 s to about 1.25 s. In some embodiments, the product stream hasa discharge pressure from the downstream end from 15 kPag to 250 kPag, or from 25 kPag to 250 kPag, or from 50 kPag to 250 kPag, or from 15 kPag to 200 kPag, or from 25 kPag to 200 kPag, or from 50 kPag to 200 kPag, or from 15 kPag to 120 kPag, or from 250 kPag to 2,500 kPag, or from 2,500 kPag to 12,000 kPag, or from 5,000 kPag to 12,000 kPag. In some embodiments, the apparatus may be used to convert a hydrocarbon in the process vapor or fluid to a product, such as a C2-C4 alkene, syngas, or a combination of these. For example, in some embodiments the apparatus is used to convert ethane in the process vapor or fluid to ethylene.

[0076] In still another embodiment, a method for hydrocarbon conversion can be implemented using the apparatuses described herein. The method includes heating the interior cavity of a furnace having an upper end and a lower end; flowing a process vapor or fluid through one or more process tubes extending through the interior cavity of the furnace; converting at least a portion of the hydrocarbon into a product; and discharging a product stream comprising the product from a downstream end of the furnace, where the interior cavity is heated by one or more panels secured and disposed within the interior cavity of the furnace and operable to receive electrical power from a power source. The one or more panels include an electrically resistive material having a plurality of apertures defined therein.

[0077] The method is suitable for use in various hydrocarbon conversion processes. In some embodiments, the method is suitable for converting a lower alkane into an alkene. In some embodiments, the method is suitable for converting ethane into ethylene. In some embodiments, the method is suitable for converting methane and steam into carbon monoxide and hydrogen (syngas). Syngas can be further processed to produce relatively pure hydrogen.

[0078] In some embodiments, the process vapor or fluid comprises a C2-C4 alkane. In some embodiments, the process vapor or fluid comprises ethane. In some embodiments, the process vapor or fluid comprises ethane and steam. In some embodiments, the process vapor or fluid comprises methane. In some embodiments, the process vapor or fluid comprises methane and steam. In some embodiments, the process vapor or fluid comprises natural gas, naphtha, liquefied petroleum gas, methane, ethane, propane, butane, or combinations thereof.

[0079] In some embodiments, the product stream comprises a C2-C4 alkene. In some embodiments, the product stream comprises ethylene. In some embodiments, the product stream comprises carbon monoxide. In some embodiments, the product stream comprises hydrogen. In some embodiments, the product stream comprises syngas.

[0080] A person skilled in the art would understand that different hydrocarbon conversion processes may have different process conditions and that optimization of process conditions isgenerally recommended in order to achieve particular process goals. A user may choose conditions that promote yield over selectivity to a desired product, and vice versa. Process conditions include, but are not limited to, the temperature within the interior cavity, the residence time of the process vapor or fluid, and consequently the hydrocarbon, within the interior cavity, flow rate of the process vapor or fluid, the heat flux profile applied to the interior cavity, and the relevant pressure settings (within the furnace and the pressure differential).

[0081] The temperature within the interior cavity plays a pivotal role in the method of hydrocarbon conversion process. The temperature must be high enough to promote conversion of the hydrocarbon but low enough to reduce formation of unwanted byproducts. Also, as the process vapor or fluid moves through the interior cavity and products are produced there may be a subtle shift to additional products that are the result of conversion of the product itself. It is contemplated that the heat flux profile along the length of the interior cavity may be constant or the heat flux profile along the length may be varied. For example, it may be beneficial to heat the upstream regions of the interior cavity at a higher heat flux to quickly initiate the reaction and subsequently lower the heat flux of the downstream region to match the decreased reaction rate once the feed is consumed and its concentration is lower. The heat flux profile along the length may vary in steps or may be gradual. The one or more panels may be designed to allow optimization of the heat flux profile along the length.

[0082] In some embodiments, the process vapor or fluid in the interior cavity is heated to a temperature of from 115°C to 1000°C, or from 450°C to 950°C, or from 650°C to 900°C. In some embodiments, the one or more panels provide the heat flux necessary to heat the process vapor or fluid to a temperature of from 115°C to 1200°C, or from 450°C to 1100°C, or from 650°C to 1000°C.

[0083] In some embodiments, the process vapor or fluid has a residence time in the furnace from 0.02 s to 4.5 s, from 0.05 s to 4.5 s, from 0.1 s to 2.5 s, or from 0.1 s to 1.25 s. In some other embodiments, the product stream has a pressure at an outlet of the furnace from 15 kPag to 250 kPag, or from 25 kPag to 250 kPag, or from 50 kPag to 250 kPag, or from 15 kPag to 200 kPag, or from 25 kPag to 200 kPag, or from 50 kPag to 200 kPag, or from 15 kPag to 120 kPag, or from 250 kPag to 2,500 kPag, or from 500 kPag to 2,000 kPag, or from 2,500 kPag to 12,000 kPag, or from 5,000 kPag to 12,000 kPag.EXAMPLESComparative Example 1 (Single Flat Panel)

[0084] Using commercially available modeling software from Ansys Maxwell, a state of the art flat panel was modeled to illustrate the drawbacks and challenges with panel shaped electric heat generation. The panel material included FeCrAl alloy. The size of the panel was 1 meter by 1 meter and 0.003 meters thick. Small extensions to the panel for electrical contact points had the same thickness as the main panel and were 0.12 meters long and extended from the main part of the panel by 0.01 meter. Electrical contact points were located on the top and bottom but aligned with opposite sides of the panel. Electrical current of 5,000 Amperes was applied to one contact and the other was maintained at ground (zero) voltage. The voltage potential to drive this amount of current in this geometry and material was 8.3 Volts. Electrical current calculated from the model is illustrated in FIG. 9. The flux in Amperes / m2was highest near the electrical contacts. Very little current approaches the comers farthest away from the electrical contacts. Though the middle of the panel experiences relatively even and close to average current fluxes, the difference between the maximum and the average flux is several orders of magnitude. The effects this would have on heating is illustrated in FIG. 10, which plots the ohmic loss near the surface of the panel. The ohmic loss from the electrical current will be dissipated by the heat generated from the panel. The ohmic loss, which powers the heat generation, was about 25 times more in the area near the contacts than in the middle of the panel. FIG. 10 shows there are areas of the panel with very high ohmic loss, up to 2x109W / m3and areas of low ohmic loss, as low as 0.6 W / m3. Besides of the large range, there are large regions of high and low ohmic loss, indicating there will be much nonuniformity in the heating rates and therefore temperatures generated in the panel.

[0085] The magnitude in current flow is also depicted in FIG. 11 which illustrates the magnitude of the current along three different lines across the surface of the panel. One is across the panel width at the midpoint. The other two are across the panel diagonally. One diagonal connects from one electrical contact to the other. The other diagonal connects opposite comers that are farthest from the designated electrical contact (non-excited comers). The electrical current near the contacts is about 5 times that near the middle of the panel. The opposite comers receive very little current. The deviations occur not only at isolated extreme points but substantial regions across the panel.Example 1 (Single Panel according to the present disclosure)

[0086] Using the same commercial modeling software (Ansys Maxwell), a panel with headers was modeled to illustrate the effects apertures have on the panel. The panel material again included FeCrAl alloy. The size of the panel was 1 meter by 1 meter and 0.003 meters thickexcept for 0.05 meters across two opposite sides of the panel, which was 0.043 meters thick. This formed 0.043 meters thick and 0.05 meters long electrical distribution headers on opposing sides of the panel. Small extensions to the panel for electrical contact points had the same thickness as the headers and were 0.12 meters long and extended from the main part of the panel by 0.01 meters. Electrical contact extensions were included for modeling purposes and may or may not represent the preferred geometry for electrical connection to the panel. Electrical contact points were located on the top and bottom but aligned with opposite sides of the panel. Electrical current of 5,000 Amperes of alternating current was applied to one contact and the other contact was maintained at ground (zero) voltage. The current flows and ohmic loss from the panel were calculated. FIG. 12(a) shows the ohmic loss near on surface of the panel. The effect of the header improved the nonuniformity (c.f comparative Example 1, FIG. 10) although substantial regions are still very nonuniform. Different panel designs were also modeled. The generated panel designs started from the same base configuration but added different numbers of apertures. The apertures were 0.005 meters wide and extended across the panel from one header to the other header and were aligned in a perpendicular direction to the headers. The ohmic loss for panels with 3, 6, 19, and 49 apertures are depicted in FIGs. 12(b), 12(c), 12(d), and 12(e), respectively. Adding the apertures reduced the region size with significantly high and low ohmic loss deviations. In the panel with 49 apertures in FIG. 12(e), the ohmic loss of a heating strip of FeCrAl material at the outer edge of a panel was only about 40% larger than the ohmic loss of a strip in the middle of the panel. This generates more even heat distribution and more uniform temperature.Comparative Example 2

[0087] The panel described in Comparative Example 1 was modeled using commercially available multi-physics software (Fluent), coupled with the electric modeling system. This system included three evenly spaced process tubes on either side of the radiating panel. A convection boundary condition was applied inside each process tube, simulating a process fluid at 800°C inside the tubes, which would be representative for steam cracking or steam methane reforming. Symmetry boundary conditions were applied to the sides of the domain and outside the centerlines of the tubes to represent a panel in the middle of a large furnace and to neglect wall effects as a simplification. Alternating current at a frequency of 60 Hz was applied to the panel and the input current was adjusted such that the power dissipated was 16 kW. The current distributions and the temperatures of the panel and the tubes was produced by the model. FIG. 13 shows the geometry of the model setup and the temperature profile. There were significanthot and cold spots on the panel which were significant in physical size and temperature variation, resulting in hot and cold spots on the tubes. The maximum temperature that would be achieved on the panel is over l,600°C, which is high enough to melt the FeCrAl material. FIG. 14 shows the panel alone and its temperature distribution. FIG. 15 shows the tubes alone and their temperature distribution. The difference between the highest and lowest temperatures on the tubes was 93°C. The highest process tube temperature was close to 1,000 °C, which requires high thicknesses for compatible process tube materials like incolloy or Centralloy®.Example 2

[0088] Using the same commercially available modeling software (Ansys Maxwell) coupled with multi-physics software (Fluent), a panel according to the present disclosure with headers and apertures was modeled. The panel material included FeCrAl alloy. The size was 1 meter by 1 meter and 0.003 meters thick except for 0.075 meters across two opposite sides of the panel, which was 0.053 meters thick. This formed 0.053 meters thick and 0.075 meters long electrical distribution headers on opposing sides of the pane. Small extensions to the panel for electrical contact points were the same thickness as the headers and were 0.12 meters long and extended from the main part of the panel by 0.01 meters. Electrical contact points were located on the top and bottom but aligned with opposite sides of the panel. 49 evenly spaced apertures were included in the panel, defining 50 identically sized strips of resistive material in the panel. The apertures were 0.005 meters wide and extended across the panel from one header to the other header and were aligned in a perpendicular direction to the headers. The system included three evenly spaced process tubes on either side of the radiating panel. A convection boundary condition was applied, simulating a process fluid at 800°C inside the tubes, which would be representative for steam cracking or steam methane reforming. Symmetry boundary conditions were applied to the sides of the domain and outside the centerlines of the tubes to represent a panel in the middle of a large furnace and to neglect wall effects as a simplification. Electrical alternating current at a frequency of 60 Hz was applied to one contact and the other was maintained at ground (zero) voltage. The amount of current was adjusted such that the power dissipated was 16 kW (same as in Comparative Example 2). The current distributions and the temperatures of the panel and the tubes were produced by the model. FIG. 16 shows the geometry of the model setup and the temperature profile. The thermal profile shows the highest temperature, at less than l,100°C, was still in the acceptable range for FeCrAl material. It also shows a much more even temperature distribution among the strips of resistive material defined by the apertures. The panel generates heat much more uniformly as compared to ComparativeExample 2. FIG. 17 shows the temperature profile of the panel alone. FIG. 18 shows the temperature profile of the process tubes alone. The process tubes are more uniform in temperature and overall lower temperature, about 900°C, which allows for modest thicknesses in typical high temperature furnace tube materials. The difference between the highest and lowest tube temperatures was only 28°C, showing improved heating uniformity at the same power output (vs. Comparative Example 2) that is effectively more uniform on the process as well as the panel shaped heating element.Example 3

[0089] Using the same commercially available modeling software (Ansys Maxwell) coupled with multi-physics software (Fluent), a panel according to the present disclosure with headers and apertures was modeled. The panel material comprised FeCrAl alloy. The size was 1 meter by 1 meter and 0.003 meters thick except for 0.075 meters across two opposite sides of the panel, which was 0.053 meters thick. This formed 0.053 meters thick and 0.075 meters long electrical distribution headers on opposing sides of the pane. Small extensions to the panel for electrical contact points were the same thickness as the headers and were 0.12 meters long and extended from the main part of the panel by 0.01 meters. Electrical contact points were located on the top and bottom but aligned with opposite sides of the panel. The panel contained 49 apertures, where the widths of each FeCrAl strip plus its adjacent aperture were evenly spaced. The aperture widths were variable and were generated according to the function:where x was the position from one edge of the panel and L was the width of the panel. This made wider apertures near the edge and a minimum aperture size near the center of the panel. The parameter, a, dictated the relative sizes between the resulting FeCrAl strips in the center of the panel vs. ones at the panel’s edge. The panel is shown in FIG. 19. The parameter a was set to 1.2. The electrical performance of the panel was modeled under conditions of 5,000 Amperes of alternating current at at frequency of 60 Hz applied to one contact and the other was maintained at ground (zero) voltage. The ohmic loss in various FeCrAl strips was calculated. Results for selected strips are given in Table I (c.f FIG. 19). The deviation between ohmic loss at the edge of the panel vs. the middle was about 5%.Table 1* * *

[0090] The above specification and examples provide a complete description of the structure and use of exemplary embodiments. Although certain embodiments have been described above with a certain degree of particularity, or with reference to one or more individual embodiments, those skilled in the art could make numerous alterations to the disclosed embodiments without departing from the scope of this invention. As such, the various illustrative embodiments of the present systems are not limited to the particular forms disclosed. Rather, they include all modifications and alternatives falling within the scope of the claims, and embodiments other than the one shown may include some or all of the features of the depicted embodiment. For example, components may be combined as a unitary structure, and / or connections may be substituted. Further, where appropriate, aspects of any of the examples described above may be combined with aspects of any of the other examples described to form further examples having comparable or different properties and addressing the same or different problems. Similarly, it will be understood that the benefits and advantages described above may relate to one embodiment or may relate to several embodiments.

[0091] The claims are not intended to include, and should not be interpreted to include, means-plus- or step-plus-function limitations, unless such a limitation is explicitly recited in a given claim using the phrase(s) “means for” or “step for,” respectively.

Claims

CLAIMS1. An apparatus for hydrocarbon conversion comprising: a furnace for heating hydrocarbons, wherein the furnace comprises an interior cavity and one or more process tubes extending through the interior cavity and operable to receive a process vapor or fluid at an upstream end of the furnace and discharge a product stream at a downstream end of the furnace; and one or more panels disposed and secured within the interior cavity of the furnace and operable to receive electrical power from a power source, wherein the one or more panels comprise an electrically resistive material and a plurality of apertures defined therein wherein the one or more panels are operable to generate heat on the flow of an electrical current to heat the interior cavity of the furnace.

2. The apparatus of claim 1, further comprising a securing mechanism operable to secure the panel to an inner wall of the furnace wherein the securing mechanism comprises an electrically insulative material.

3. The apparatus of claim 2, wherein the securing mechanism comprises a mount, a peg, a hook, a bracket, a fastener, a clamp, or a support.

4. The apparatus of any of claims 1-4, wherein the one or more process tubes comprise a plurality of process tubes.

5. The apparatus of claim 4, wherein the panel is disposed on an end wall of the furnace such that the panel is facing perpendicular to the plurality of process tubes.

6. The apparatus of claim 5, wherein the plurality of process tubes are arranged in at least two rows and the panel is arranged in between the rows such that a front side and a back side of the panels radiates heat to the plurality of process tubes.

7. The apparatus of any of claims 1-6, wherein the electrically resistive material comprises a metal alloy.

8. The apparatus of claim 7, wherein the metal alloy comprises stainless steel, constantan, nickel-containing alloy, cobalt-containing alloy, chromium-containing alloy, aluminum- containing alloy, titanium-containing alloy, zirconium-containing alloy, hafnium-containing alloy, niobium-containing alloy, molybdenum-containing alloy, tantalum-containing alloy,tungsten-containing alloy, tin-containing alloy, gallium-containing alloy, manganese- containing alloy, and iron-containing alloy.

9. The apparatus of claim 8, wherein the metal alloy comprises FeCrAl or NiCrFe.

10. The apparatus of any of claims 1-9, wherein the plurality of apertures form a plurality of electrically isolated areas within the electrically resistive material.

11. The apparatus of any of claims 1-10, wherein the interior cavity has a height of five meters or more, a width of 0.5 meters or more and a length of one meter or more.

12. The apparatus of any of claim 1-11, wherein the electrically resistive material is mechanically reinforced by plating.

13. A system comprising a process vapor or fluid and the apparatus of claim 1.

14. A method for hydrocarbon conversion, the method comprising: flowing a process vapor or fluid comprising a hydrocarbon through at least one process tube extending through an interior cavity of a furnace of an apparatus wherein the apparatus further comprises one or more panels comprising an electrically resistive material having a plurality of apertures defined therein; providing, by the one or more panels, heat to an external surface of the process tube to convert at least a portion of the hydrocarbon into a product; and discharging a product stream comprising the product from the furnace.

15. The method of claim 14, wherein the hydrocarbon comprises natural gas, methane, naphtha, liquefied petroleum gas, ethane, propane, butane, gas condensate, gas oil, diesel, jet fuel, gas-to-liquid fuel, bio feedstock or mixtures thereof and the product comprises at least one of a C2-C4 alkene, carbon monoxide or hydrogen.