A furnace and a method for maintaining a furnace component of a furnace

Abstract

The present invention relates to a furnace for performing a chemical process and / or for heating a process medium, wherein the furnace (100) comprises a number of walls (110, 120, 125) defining an interior volume (130) of the furnace (100), wherein at least one wall (110) of the number of walls comprises a frame structure (160) and at least one furnace component (150), particularly comprising heating means for heating the interior (103) volume of the furnace (100), provided in the frame structure (160), said at least one wall (110) defining a respective outer wall plane (190); wherein at least one of the at least one furnace component (150) is configured to be assembled into the corresponding wall (110) by means of a pivot mechanism (240) such that the respective furnace component (150) can be pivoted out of and back into the wall plane (190) of the respective wall (110) of the furnace.

Description

[0001] Description

[0002] A furnace and a method for maintaining a furnace component of a furnace

[0003] The present invention relates to a furnace for performing a chemical process and / or for heating a process medium as well as to a method for accessing, particularly maintaining, a furnace component of such a furnace.

[0004] Background of the invention

[0005] In a number of processes in the chemical industry, reactors or furnaces are used in which one or more reactants are passed through heated tubes where they are catalytically or non- catalytically reacted or heated up. The heating serves in particular to overcome the activation energy required for the chemical reaction taking place and, in the case of endothermic reactions, to provide the necessary energy for the chemical reaction. The reaction can proceed endothermically overall or, after overcoming the activation energy, exothermically.

[0006] Examples of such processes are steam cracking, various reforming processes, in particular steam reforming, dry reforming (carbon dioxide reforming), mixed reforming processes, processes for the dehydrogenation of alkanes and the like. In steam cracking, the tubes are guided through the reactor or furnace in the form of coils, which have at least one reverse bend in the furnace, whereas in steam reforming, tubes are typically used which run through the furnace without a reverse bend. The present invention may also be used in connection with so- called "millisecond" or "single-pass" reactors which are characterized by very low dwell times.

[0007] Further applications of the present invention are furnaces for performing a reverse water gas shift (RWGS) reaction of carbon dioxide and hydrogen to form carbon monoxide and water, dehydrogenation of oxygenates such as a reaction of methanol to formaldehyde and hydrogen, cleavage of ammonia to yield gaseous nitrogen and hydrogen, dehydrogenation of so-called liquid organic hydrogen carriers (LOHC) as known to the skilled person, and reforming of methanol and glycerol (as far as not already included by the term "reforming" used above).

[0008] The present invention is suitable for all embodiments of furnaces used for such processes as well as for furnaces for heating a process medium. Purely by way of illustration, reference is made to the articles "Ethylene", "Gas Production" and "Propene" in Ullmann's Encyclopedia of Industrial Chemistry, for example the publications dated April 15, 2009, DOI: 10.1002 / 14356007.a10_045.pub2, December 15, 2006, DOI:

[0009] 10.1002 / 14356007. a12_169.pub2, and June 15, 2000, DOI: 10.1002 / 14356007.a22_211.

[0010] Document US 5 393 037 A discloses a smelting unit having a furnace vessel which is mounted on a furnace rocking cradle and which can be closed by a cover, and bar electrodes which can be lowered into the furnace vessel and which can be raised and lowered by means of electrode lift devices, in which the electrode lift devices are carried by a portal assembly. In a lowered position the portal assembly lies on a support holder of the vessel substructure or the furnace rocking cradle, respectively, and, in that position, can be tilted with the furnace vessel. It can be released from the furnace vessel and pivoted to the side by a lift post of a stationary lifting / pivoting mechanism. When the unit has two vessels which are arranged side-by-side, the bar electrodes can be associated alternately with one vessel or the other by means of the lifting / pivoting mechanism.

[0011] Further, document US 3 768 980 A refers to a furnace for catalytic, endothermic reactions comprising at least one row of substantially vertical reactor tubes in at least one furnace chamber, inlet pigtails compensating for thermal expansions of the reactor tubes, outlet means including at least substantially straight connecting pipes forming substantially right angles with said reactor tubes, and suspension means of said reactor tubes, said means being disposed at the lower end of said reactor tubes allowing a substantially frictionless movement of the lower ends of said reactor tubes in all directions within a substantially horizontal plane large enough to compensate for the thermal expansions of said outlet means in order to make the structure of the furnace chamber independent of thermal expansions of the reactor tubes and simultaneously simplify the outlet piping means.

[0012] The tubes of corresponding furnaces are conventionally heated by using burners. The tubes are, for this purpose, guided through a combustion chamber in which the burners are also arranged. However, it is also possible to support or replace the burners in corresponding furnaces by electrical heating means with no or reduced local carbon dioxide emissions. In addition to direct electrical heating, in which current is applied to the tubes themselves, for example in a known star (point) circuit, and other types of heating, which are not explained in detail here, concepts also exist in particular for so-called indirect electrical heating. Such indirect electrical heating can e.g. be carried out using electrically operated radiative heating elements ("radiant heaters") suitable for heating to the high temperatures required for the reactions mentioned, such heating elements being arranged within the furnace in such a way that they are not in direct contact with the reaction tubes. The heat transfer takes place predominantly or exclusively in the form of radiant heat. In these kinds of indirectly heated furnaces, the furnace components, e.g. corresponding heating elements, can have a limited service life which can lead to high levels of maintenance, in particular in furnaces with high process temperatures, e.g. in cracking furnaces, reforming furnaces or DRI (direct reduction iron) furnaces. It is therefore desirable to improve furnaces with radiative heating elements for indirect heating.

[0013] Disclosure of the invention

[0014] The present invention relates to a furnace and to a method for accessing, in particular maintaining, a furnace component of such a furnace with the features of the independent claims. Embodiments and advantages form the subject-matter of the dependent claims and of the subsequent description.

[0015] The furnace or process furnace is provided for performing a chemical process, i.e. a process for carrying out a chemical reaction, and / or for heating a process medium. For this purpose, tubes or reaction tubes (in the following generally "tubes") to be heated can be provided in an interior volume or chamber or process chamber of the furnace such that one or more reactants can be passed through the correspondingly heated tubes, where they are catalytically or non- catalytically reacted. It is also possible to pass a process medium to be heated through the correspondingly heated tubes. The furnace can particularly be provided for performing a steam cracking process, various reforming processes, in particular steam reforming, dry reforming (carbon dioxide reforming), mixed reforming processes, processes for the dehydrogenation of alkanes and the like. The furnace can particularly be a cracking furnace, a reforming furnace, a direct reduced iron (DRI) furnace etc.

[0016] The furnace comprises a number of walls, e.g. side walls, a front-end wall, a back-end wall, a top wall and a bottom wall. These walls define or enclose the interior volume of the furnace, in which tubes to be heated can be provided. At least one wall of the number of walls comprises a frame structure and at least one furnace component provided in or inserted into the frame structure. The frame structure particularly comprises a number of beams or bars connected with each other, expediently a number of massive bars and beams arranged horizontally, vertically and / or diagonally and connected with each other in order to form a load-bearing frame structure. These beams or bars especially define or enclose a number of recesses, wherein the furnace components can be provided. The furnace components can e.g. comprise elements, which are needed for operating the furnace. For example, the furnace components can comprise heating means for heating the interior volume of the furnace, electrical wiring, sensors, etc. The furnace components can e.g. be equivalent or identically constructed. However, the furnace components can also be constructed individually and differently from each other.

[0017] Expediently, several furnace components can be provided in a vertical column being arranged on top each other and neighbouring each other vertically or being at least partly separated by a horizontal part (e.g. beam or bar) of the frame structure. Expediently, several furnace components can be provided in a horizontal row being arranged next to each other and neighbouring each other horizontally or being at least partly separated by a vertical part (e.g. beam or bar) of the frame structure. Particularly, a multitude of furnace components can be provided in an array of multiple rows and columns.

[0018] Expediently, each furnace component can be provided as an interchangeable, exchangeable or replaceable unit or module. If necessary, e.g. during maintenance or in case of a defect, the corresponding furnace component can individually be replaced by a respective spare part. Each furnace component can particularly be fastened by means of detachable fastening means, expediently to the frame structure and / or to a neighbouring furnace component. Detachable fastening means of that kind can e.g. comprise screws, bolts, brackets, flange connections, etc.

[0019] In particular, several walls of the furnace can comprise correspondingly arranged furnace components, especially arranged in rows and / or columns. For example, each one of a pair of opposing side walls can comprise corresponding furnace components. Further, each side wall of the furnace can comprise corresponding furnace components. However, it is also possible that only one wall comprises corresponding furnace components.

[0020] According to the present invention, at least one wall of the furnace comprises a frame structure and one or more furnace components and defines a respective outer wall plane, i.e. a plane at the outside of the furnace wall, said plane particularly forming the outer surface of the furnace wall. Further at least one of the at least one furnace component is configured to be assembled into or connected to the corresponding wall, in order to become a part of this wall, by means of a pivot or swivel mechanism such that the respective furnace component can be pivoted out of the respective outer wall plane and also back into the wall plane of the respective wall of the furnace. The expression that a furnace component “is configured to” be assembled into the corresponding wall is to be understood to include a configuration where the furnace component is already assembled into the corresponding wall by means of the pivot mechanism. On the other hand, a configuration is also encompassed where a pivot mechanism is e.g. to be attached to the corresponding wall parts in order to enable the respective furnace component to be pivoted out of and back into the respective outer wall plane.

[0021] Being able to pivot the respective furnace component out of the outer wall plane by means of the pivot mechanism particularly allows to easily and flexibly access the respect furnace component, expediently for an easy and fast maintenance, inspection, and repair of the component.

[0022] In an embodiment, the pivot mechanism comprises a first support element being provided at the respective furnace component, which is to be pivoted, especially at an exterior surface of the respective furnace component, i.e. at a surface facing away from the interior volume of the furnace, a second support element being provided at the respective wall external to or outside of the respective furnace component. The first support element is configured to be pivoted relative to the second support element. Again, the term “configured to” is to be understood as mentioned above. The second support element expediently defines a pivot point or rotation point for the pivoting movement of the respective furnace component. The second support element can be provided at a predetermined position at the wall outside of the respective furnace element. The second support element is therefore not provided at the respective furnace component itself.

[0023] In an embodiment, the first support element is attached to or directly coupled with the second support element. The first and second support elements therefore interact directly with each other in order to enable the pivoting movement of the furnace component. The second support element can thus expediently be provided as a suspension point for rotatably suspending the furnace component. By means of the first and second support element, the furnace component can directly be hinged on a respective pivot point provided at the furnace wall. For example, the furnace component can be hinged on a support structure of the furnace wall for supporting the component. It is also possible that two or more first support elements are provided at the respective furnace component and that a corresponding number of second support elements are provided for interacting with the respective first support elements.

[0024] In an embodiment, a pivoting element is provided and configured to be attached to the first support element and the second support element. The first and second support elements have the function of "supporting" or being connected with the pivoting element. The pivoting element or swivelling element is configured to be attached or to be detachably fastened to the first support element and the second support element such that, in the attached state, the respective furnace component can be pivoted or swivelled by means of the pivoting element relative to the frame structure, i.e. relative to the outer wall plane of the respective wall. For example, the pivoting element can be provided as a hinge element.

[0025] In particular, by means of the first support element, the pivoting element can be connected with the respective furnace component. The first support element is therefore especially provided as a mounting or fastening point for fixedly fastening the pivoting element to the respective furnace component. The second support element can expediently define a pivot point or rotation point relative to the respective furnace component, wherein the pivoting element can expediently be coupled to this pivot point. The second support element is therefore especially provided as a suspension point for rotatably suspending the pivoting element. Since the respective furnace component is especially fastened to the furnace wall by means of detachable fastening means, the furnace component can particularly be disconnected or unfastened from the furnace wall or from the remaining components of the wall such that the respective furnace component can be moved relative to the outer wall plane or the frame structure of the wall. Therefore, with the pivoting element being attached to the first and second support elements and with the furnace component being unfastened from the furnace wall, the respective furnace component can be pivoted around the pivot point defined by the second support element.

[0026] It is also possible that two or more first support elements are provided at the respective furnace component and that a corresponding number of second support elements are provided. Therefore, a corresponding number of pivoting elements can be attached to the various first support elements of the respective furnace component and to the corresponding second support elements. The respective furnace component can therefore be pivoted by means a multitude of pivoting elements similarly to door hinges, expediently stabilizing and supporting the pivoted furnace component.

[0027] In particular, several of the furnace components of the respective wall can each comprise a corresponding first support element. Expediently, all furnace components provided in the respective furnace wall each comprise a corresponding first support element. Accordingly, a corresponding number of second support elements is provided in the remaining parts of the corresponding wall, each second support element being provided at a corresponding predetermined position at the wall external to the respective furnace component and relative to the corresponding first support element. The present invention therefore provides a mechanism, which allows to pivot the respective furnace component out of its position in the respective furnace wall, such that the pivoted component can easily be accessed, in particular in order to facilitate maintenance of the respective furnace component. By means of the pivot mechanism, the respective furnace component can particularly be opened like a door. After accessing the furnace component, e.g. after performing maintenance, the furnace component can easily be pivoted back again to its original position in the frame structure.

[0028] Conventionally, removing furnace components from furnace walls, e.g. for maintenance, can oftentimes be elaborate, time-consuming and cost-intensive. For example, furnace components can conventionally mostly only be removed by means of a crane and an auxiliary construction. Further, reconstruction of platforms might be necessary. For example, a complete removal of the furnace component with subsequent transport to the ground might be necessary in case of maintenance, inspections, or minor repairs. In addition to the high cost of the crane and the modification of the platforms, a considerable amount of time might be required for disassembly, transport to the ground and reassembly, which can significantly extend the duration of the actual maintenance. Further, when reassembling the furnace component to the frame structure, the furnace component oftentimes needs to be slid into its position exactly horizontally with only a very little clearance up and down, oftentimes only in the range of a few millimetres.

[0029] In contrast to that, the present invention allows to easily remove and reassemble furnace components with low effort in a time-saving and cost-saving manner. By providing the pivot mechanism, the furnace components can particularly be modified with a hinge function, such that the furnace components can be opened like doors. A complete disassembly for maintenance purposes is therefore not necessary. The furnace components thus especially do not need to be completely dismantled and moved to the ground, but can be pivoted, swung or folded up. Particularly, a crane is not needed for removing and reassembling the furnace component. Further, a reconstruction of platforms is especially not necessary. Costs and duration of maintenance can therefore considerably be reduced. The invention expediently allows the construction of large furnaces, wherein large parts of the furnace walls are provided with corresponding furnace components. The furnace components can particularly be components which regularly need to be maintained.

[0030] Especially, the pivot mechanism can only temporarily be attached to the respective furnace component or, in the above embodiment, the pivoting element can only temporarily be attached to the support elements such that only a limited number of pivoting mechanisms or elements are required to open an appropriate number of furnace components for maintenance purposes. After having pivoted the respective furnace component back to its original position in the frame or wall structure, the pivoting element can particularly be detached and removed from the support elements (same applies to the more general pivot mechanism). Expediently, when several or all of the furnace components are provided with corresponding first support elements, the pivoting element can easily, flexibly and individually be coupled with the corresponding furnace component, which shall be removed from the frame structure. The pivoting element can afterwards especially be detached from this furnace component and can be attached to another component, which needs to be removed from the frame structure.

[0031] On the other hand, in case the second support element is provided at the frame structure, the corresponding pivoting element might as well be fixedly attached to the first and second elements.

[0032] The invention further refers to a method for accessing, particularly maintaining, a furnace component of a furnace. Advantages and embodiments of the method according to the invention and of the furnace according to the invention shall arise from the present description in corresponding manner.

[0033] According to the method, the respective furnace component is pivoted by means of the pivot mechanism out of the respective wall plane of the respective wall of the furnace, and then the pivoted respective furnace component is accessed, particularly with the aim of maintenance or repair.

[0034] In an embodiment, a pivoting element is attached to a first support element and a second support element of the respective furnace component of a furnace according to the above discussed embodiment. The respective furnace component can further be unfastened from the furnace wall by means of the corresponding detachable fastening means, e.g. by unfastening or loosening a corresponding flange connection. The respective furnace component is then pivoted by means of the pivoting element relative to the frame structure. Maintenance of the correspondingly pivoted respective furnace component is then performed. In the course of the maintenance, the furnace component can be inspected with respect to damages or signs or wear. If necessary, repair of the furnace component can be performed.

[0035] According to an embodiment of the present invention, the second support element is provided at the frame structure and / or at another furnace component than the respective furnace component, particularly at a furnace component adjacent to the respective furnace component, which is to be pivoted (in the following also “at a neighbouring furnace component”). This neighbouring furnace component is particularly provided in the frame structure vertically above or vertically below or horizontally beside the respective furnace component. Particularly, the neighbouring furnace component is provided directly adjacent to the respective furnace component. For example, if two or more furnace components are provided in the frame structure directly adjacent to each other with little or no parts of the frame structure between them, the second support element for pivoting the respective furnace component can especially be provided at the immediate neighbouring furnace component, expediently at the outer surface of this neighbouring component. If, for example, a part of the frame structure is provided directly adjacent to the respective furnace component, the second support element for pivoting this furnace component can especially be provided at this frame structure part immediate neighbouring the furnace component. Expediently, no additional cost-intensive frames, beams, bars, etc. need to be elaborately added to the frame structure for suspending and pivoting the frame component, but the second support element as suspension point for the respective furnace component can especially be attached to the adjacent furnace component or the frame structure

[0036] According to an embodiment, a part of the respective furnace component is arranged behind a support structure of the furnace wall for supporting the at least one furnace. The pivot mechanism is configured such that the respective furnace component can be pivoted relative to this support structure of the furnace wall. The support structure is particularly a part of the furnace wall and can e.g. be provided as a steel structure or a steel beam of the frame structure. The respective part of the furnace component, which is arranged behind this support structure, is particularly arranged between the support structure and the interior volume of the furnace. This way, the inside surfaces of the support structure facing towards the interior volume of the furnace and the space behind this inside surface can particularly be utilised for arranging part of the furnace component. By being able to pivot the furnace component relative to the support structure, the furnace component can still easily be accessed if necessary.

[0037] According to an embodiment of the present invention, the second support element is provided at a support structure of the furnace wall for supporting the at least one furnace component. The second support element can expediently be provided at an inside surface of the support structure, i.e. a surface of the support structure facing towards the interior volume of the furnace. The first support element may then directly be attached to the second support element provided at the support structure. This way, the pivot mechanism can expediently be configured such that the furnace component can be pivoted relative to the support structure. Inside surfaces of the support structure facing towards the interior volume of the furnace are usually not easily accessible or not accessible at all from the outside of the furnace. However, providing the second support element for pivoting the furnace component at this inside surface allows usage of the internal wall space facing towards the interior furnace volume. A better usage of heating area and a reduction of the overall heater size can therefore be achieved.

[0038] According to an embodiment, the first support element is provided as at least one first bolt element fastened to the respective furnace component. For example, this first bolt element or these first bolt elements can be welded to the respective furnace component, for example to its exterior surface. The pivoting element is configured to be mounted on this at least one first bolt element, e.g. by sliding the pivoting element onto the bolt element(s). Alternatively or additionally, according to an embodiment, the second support element is provided as at least one second bolt element, which can be fastened to, e.g. welded to, the frame structure or the neighbouring furnace component. The pivoting element is configured to be mounted on this second bolt element or these second bolt elements, e.g. by suspending the pivoting element on the bolt element(s). Therefore, no cost-intensive frames, beams, bars, etc. are needed for suspending and pivoting the frame component, but the support elements can be provided as bolts which can easily be fastened to the furnace components and / or the frame structure in a space saving manner.

[0039] According to an embodiment, the respective furnace component comprises a flange element, which is especially provided at the exterior surface of the respective furnace component, especially as a frame of the exterior surface. The respective furnace component is configured to be detachably fastened to the frame structure and / or to a neighbouring furnace component by means of this flange element. Especially, the flange element can be fastened to a corresponding flange element as counterpart provided at the frame structure and / or the neighbouring furnace component, e.g. by means of screws, bolts etc. The respective furnace component can therefore detachably be fastened to the furnace wall by means of a flange connection. Particularly, the first support element can be provided at this flange element of the respective furnace component. For example, the support element can be provided as bolt(s) welded between holes in this flange element. The first support element, can thus be arranged in an easy, space saving manner.

[0040] According to an embodiment, the pivoting element is configured to be detachably attached to the second support element such that the pivoted respective furnace component can be removed from the frame structure. When the respective furnace component is pivoted, the pivoting element can especially be detached or decoupled from the second support element, e.g. by sliding the pivoting element off of the second support element. The respective furnace component is then not connected or coupled with the furnace wall anymore and can be removed. The pivoting element is therefore particularly designed in such a way that it is possible to lift the complete furnace component upwards or sideward, similar to a door leaf. The pivoting element therefore allows to easily remove the furnace component, e.g. when the component is damaged or shall be replaced by a new component.

[0041] According to an embodiment, the respective furnace component is configured to be electrically connected with a neighbouring furnace component by means of electrical connection means. The electrical connection means are configured to electrically disconnect the respective furnace component from the neighbouring furnace component when the respective furnace component is pivoted by means of the pivoting mechanism or element. These electrical connection means can especially be provided at an inner surface of the furnace component and / or at an inner surface of the neighbouring furnace component, i.e. at surfaces facing the interior volume of the furnace. The electrical connection means can especially comprise electric contacts provided at the respective furnace component and the neighbouring furnace component. For example, when the respective furnace component is assembled in the frame structure, an electric contact of this component, e.g. provided at the inner surface of the component, can mechanically and electrically contact an electric contact of the neighbouring component, e.g. also provided at the inner surface of this component, thereby establishing the electrical connection to the neighbouring component. When the respective component is pivoted, its electric contact is especially disconnected from the electric contact of the neighbouring component thereby interrupting the electrical connection to the neighbouring component.

[0042] According to an embodiment, at least one side surface of the respective furnace component is formed, especially curved or inclined e.g. relative to the outer surface of the respective furnace component, such that a form, especially a curvature or inclination angle, of the respective side surface corresponds to a trajectory of a pivoting movement of the respective furnace component when the respective furnace component is pivoted by means of the pivot mechanism such that the respective side surface abuts on a correspondingly formed side surface of a furnace component adjacent to the respective furnace component or of the frame structure when the respective furnace component is pivoted into the respective wall plane. For example, the curvature of the side surface can correspond to a movement curve or opening curve of the pivoting movement. Especially, two opposing side surfaces of the component can accordingly be formed. For example, a lining element or an insulation element can accordingly be formed as the respective side surface. Further, side surfaces of the frame structure and neighbouring furnace components are especially formed accordingly. This way, when the respective furnace component is assembled in the frame structure, its side surfaces especially rests against the side surface of the frame structure or the neighbouring component. Due to this closure, there is especially no friction between the adjacent components and there is expediently no resistance when pivoting the components. Furthermore, gaps or joints between the components can especially seal themselves when the components are assembled.

[0043] According to an embodiment, the at least one furnace component is provided as at least one electrical heating unit. These electrical heating units are especially configured for electrically heating the interior volume of the furnace and can electrically be operated to radiate thermal energy for heating the furnace interior to a corresponding temperature, e.g. required for performing the corresponding chemical process or for heating the process medium to a predetermined temperature. The electrical heating units are particularly provided as modular units, which can comprise an actual heating element or heating means as well as other elements, e.g. for insulation, for mounting etc. Heating units of that kind can have a limited service life, wherein frequent maintenance might be required. The pivoting mechanism or element can therefore particularly be used in order to facilitate maintenance of heating units of that kind.

[0044] According to an embodiment, each electrical heating unit comprises a heating element and / or an insulation element and / or a panel element. The heating element is particularly provided as the actual heating means for heating the interior of the furnace. For example, the heating element can be an electrical heating wire or a heating material, e.g. SiC or MoSi2. The insulation element can expediently be provided for insulating the interior of the furnace from the exterior environment. The panel element can expediently be provided as a cover or shrouding of the exterior surface of the corresponding furnace wall and can e.g. be provided as a steel plate. The electrical heating units can further comprise other elements, e.g. electrical wirings and connection means. For example, each heating unit can further comprise welded-on stiffening ribs, expediently for stiffening the respective heating unit against wind loads, etc.

[0045] According to an embodiment, the respective furnace component, which has been pivoted away from its position within the frame structure, is pivoted by means of the pivoting mechanism or element back to its original position within the frame structure, especially after maintenance has been completed on the pivoted component. The pivot mechanism or more specially the pivoting element is then detached or unfastened from the first support element and the second support element and can be removed. The respective furnace component is particularly fastened again to the frame structure and / or the neighbouring furnace component, especially by means of the detachable fastening means, e.g. means of the corresponding flange connection. Further advantages and developments of the invention are specified in the description and the associated drawings.

[0046] It goes without saying, that the features named above and still to be explained below can be used not only in the combination indicated respectively, but also in other combinations or in a stand-alone manner, without going beyond the scope of the present invention.

[0047] The invention is illustrated schematically in the drawings on the basis of exemplary embodiments and will be described in detail in the following with reference to the drawings.

[0048] Description of drawings

[0049] Fig. 1 schematically shows an embodiment of a furnace according to the present invention in a sectional side view.

[0050] Fig. 2 schematically shows a wall of a furnace according to the prior art in a perspective view.

[0051] Fig. 3 schematically shows a wall of a furnace according to an embodiment of the present invention in different views a to c.

[0052] Detailed description of the drawing

[0053] Fig. 1 shows an embodiment of a furnace 100 according to the present invention in a schematic sectional side view.

[0054] The furnace 100 or process furnace is provided for performing a chemical process, e.g. a steam cracking process, a reforming process etc. The furnace 100 can also be provided for heating a process medium. For example, the furnace 100 can be provided as a cracking furnace, a reforming furnace, a direct reduced iron (DRI) furnace etc.

[0055] The furnace 100 comprises several walls, which define and enclose an interior volume or process chamber 130. For example, the furnace can comprise four side walls 110, wherein only two of these side walls are shown in Fig. 1 , as well as top wall 120 and a bottom wall 125.

[0056] A number of tubes or reaction tubes 140 are provided in the process chamber 130. One or more reactants can be passed through these tubes 140, where they are catalytically or non- catalytically reacted. In order to overcome an activation energy of the corresponding chemical reaction, the tubes 140 shall be heated to a predetermined temperature. It is also possible to pass one or more process media to be heated thought the tubes140, wherein the tubes 140 are heated to a predetermined temperature.

[0057] For this purpose, electrical heating units 150 are provided in one or several of the furnace walls, for example in each of the side walls 110. Each of the sidewalls 110 comprises a frame structure 160, wherein the electrical heating units 150 are provided in this frame structure 160 as furnace components. This frame structure 160 can comprise a number of vertically arranged beams, e.g. steel beams, and a number of horizontally arranged beams, e.g. steel beams, and a number of diagonally arranged beams, e.g. steel beams connected with each other to form a load-bearing frame structure. These beams define or enclose a number of recesses, wherein the heating units 150 as furnace components can be provided in these recesses.

[0058] For example, each of the side walls 110 can comprise several electrical heating units 150 arranged in an array of vertical columns and horizontal rows. As exemplarily shown in Fig. 1 , four electrical heating units 150 can be provided in a vertical column arranged on top each other.

[0059] Each electrical heating unit 150 is provided as an interchangeable, exchangeable or replaceable unit or module. If necessary, e.g. for maintenance or in case of a defect, each heating unit 150 can individually be replaced by a respective spared part.

[0060] Fig. 2 shows a wall 210 of a furnace according to the prior art in a schematic perspective side view.

[0061] In particular, Fig. 2 shows a frame structure 260 comprising vertically arranged beams 261 and horizontally arranged beams 262 defining a number of recesses, wherein heating units 250 are provided in these recesses as furnace components.

[0062] Conventionally, removing furnace components like the heating units 250 from the respective furnace wall 210, e.g. for maintenance, can oftentimes be elaborate, time-consuming and costintensive and can oftentimes require the use of a crane and an auxiliary construction as well as a reconstruction of platforms. A heating unit 250 to be maintained conventionally has to be transport from its position in the frame structure 260 to the ground and afterwards has to be transported back to its position in the frame structure 260, which can significantly extend the costs and duration of maintenance. Further, when reassembling the heating unit back to the frame structure, the heating unit oftentimes needs to be slid into its position exactly horizontally, wherein there might be very little clearance up and down, oftentimes only in range of a few millimetres.

[0063] In order to facilitate removal of furnace components like heating units from the frame structure, e.g. for performing maintenance, a pivoting element is provided according to an embodiment of the present invention for pivoting the respective furnace components relative to the frame structure, as will now be explained with reference to Fig. 3.

[0064] Fig. 3a shows the furnace wall 110 of the furnace 100 of Fig. 1 in a schematic front view. Fig. 3b and Fig. 3c both show a part of this furnace wall 110 in a schematic sectional top view. The furnace wall 110 defines an outer wall plane 190 forming the exterior surface of the wall 110.

[0065] The frame structure 160 comprises vertically arranged steel beams 161 and horizontally arranged steel beams 162. The electrical heating units 150 are arranged in the frame structure 160 in an array of horizontal rows with e.g. six heating units 150 per row and of vertical columns of e.g. four heating units 150 per column.

[0066] Each heating unit 150 comprises an exterior or outer surface 151 facing away from the interior volume 130 of the furnace 100, an inner surface 152 facing the interior volume 130 of the furnace 100, as well as side walls 153. The exterior surface 151 can for example be provided as a panel element, e.g. a steel plate, especially as a cover or shrouding of the exterior surface of the furnace wall 110. Each heating unit 150 further comprises a heating element, e.g. an electrical heating wire or a heating material like SiC or MoSi2, as actual heating means for heating the interior of the furnace. Further, each heating unit 150 can comprise an insulation element for insulating the interior of the furnace from the exterior environment. For reasons of clarity, the heating element and the insulation element are not explicitly shown in Fig. 3a, 3b and 3c.

[0067] At the outer surface 151 of each heating unit 150 a flange 155 is provided, especially as a frame of the respective exterior surface 151. The frame structure 160 also comprises flanges 165. The heating units 150 can be detachably fastened by means of their respective flange 155 to the flange 155 of a neighbouring heating unit 150 or to the flange 165 of the frame structure 160. Corresponding flanges can be fastened to each other by means of fastening means 170, e.g. by screws, bolts etc.

[0068] Each heating unit 150 comprises a first support element 210, in particular two of these first support elements 210. Each of these first support elements 210 is provided at the exterior surface 151 of the respective heating unit 150. For example, each first support element 210 can comprise two bolts fastened to the flange 155 of the exterior surface 151 of the respective heating unit 150. For example, these bolts can be welded between holes of the respective flange 155.

[0069] Further, relative to each heating unit 150, especially relative to each first support element 210, a second support element 220 is provided. These second support elements 220 for a respective heating unit 150 can be provided at the frame structure 160 or at a neighbouring heating unit 150, e.g. at a horizontally adjacent heating unit 150. Each of these second support elements 220 can be provided e.g. as a bolt fastened to the outer surface 151 of the corresponding heating unit 150 or to the frame structure 160, e.g. by means of welding.

[0070] Therefore, according to the example of Fig. 3, for each heating unit 150, two first support elements 210 and two second support elements 220 are provided, wherein each second support element 220 is particularly provided relative to one corresponding first support element 210. However, it is also possible to provide more than two pairs of first and second support elements 210, 220 for each heating unit 150 or to provide only one pair for each heating unit 150.

[0071] A pivoting element 230 is configured to be attached to each pair of a correspond first support element 210 and a corresponding second support element 220. Therefore, two of these pivoting elements 230 can be attached to each heating unit 150. For example, these pivoting elements 230 can be mounted on the bolts of the respective first support element 210, e.g. by sliding the pivoting element 230 onto these bolts. Further, the pivoting elements 230 can for example be mounted on the bolt element of the respective second support element 220, e.g. by suspending the pivoting element 230 on this bolt.

[0072] The pivoting elements 230 are configured to be attached to the respective first and second support elements 210, 220 such that the respective heating unit 150 can be pivoted or swivelled by means of the pivoting element 230 relative to the frame structure 160, i.e. out of and back into the outer wall plane 190. Thus, in this embodiment a pivot mechanism 240 is formed by a pivoting element 230 attached to the respective first and second support elements 210, 220.

[0073] The various first support elements 210 are especially provided as a mounting or fastening point for fixedly fastening the pivoting elements 230 to the respective heating unit 150. The various second support elements 220 are especially provided as a suspension point for rotatably suspending the pivoting elements 230 and particularly defines a pivot point or rotation point relative to the respective heating unit 150. When one or two pivoting elements 230 are attached to respective first and second support elements 210, 220 of a respective heating unit 150, the flange connection fastening this respective heating unit 150 to the neighbouring heating unit 150 or to the frame structure 160 can be unfastened. The respective heating unit 150 can then be moved relative to the frame structure and can be pivoted by means of the attached pivoting elements 230. The pivoting elements 230 are therefore provided as a hinge element for pivoting and opening the respective heating unit 150 like a door.

[0074] When the respective heating unit 150 is pivoted, as shown in Fig. 3b and Fig. 3c, the pivoted unit 150 can easily be accessed and maintenance can be performed. In the course of this maintenance, the pivoted heating unit 150 can be inspected and, if necessary, repairs can be performed. After maintenance has been performed, the respective heating unit 150 can be pivoted back to its position in the frame structure 160 by means of the pivoting elements 230. The pivoting elements 230 can then be detached or unfastened from the respective first and second support elements 210, 220 and can be removed. The heating unit 150 can then be fastened again to the frame structure 160 or the neighbouring unit 150 by means of the corresponding flange connection.

[0075] It is also possible to entirely remove the pivoted heating unit 150, e.g. when the unit 150 is damaged and shall be replaced by a new unit. For this purpose, the corresponding pivoting elements 230 can be detached or decoupled from the corresponding second support elements 220, e.g. by sliding the pivoting elements 230 off of the second support elements 220.

[0076] As particularly shown in Fig. 3b and Fig. 3c, the side surfaces 153 of the heating units 150 can be formed, e.g. inclined, relative to the respective outer surface 151, such that an inclination angle corresponds to a movement curve, opening curve or trajectory 250 of a pivoting movement of the respective heating unit 150. The inclined side surface 153 can e.g. be a tangent to this trajectory 250. Side surfaces 163 of the frame structure 160 can be inclined correspondingly. This way, when the heating units 150 are assembled, the corresponding side surfaces 153, 163 can rest against each other. There is especially no friction between the adjacent heating units 150 and there is expediently no resistance when pivoting the units 150. Furthermore, gaps or joints between the units 150 can seal themselves when the units 150 are assembled.

[0077] As shown in Fig. 3c, the neighbouring electrical heating units 150 can be electrically connected with each other by means of electrical connection means 180, wherein these electrical connection means 180 are configured to electrically disconnect a respective heating unit 150 from its neighbouring unit 150 when the respective heating unit 150 is pivoted by means of the pivoting elements 230. These electrical connection means 180 are e.g. provided at the inner surfaces 152 of the heating units 150. For example, the electrical connection means 180 can comprise electric contacts 181 , 182 provided at the neighbouring heating units 150. For example, when the respective heating unit 150 is assembled in the frame structure 160, an electric contact 181 of this unit 150 mechanically and electrically contacts an electric contact 182 of the neighbouring heating unit 150, thereby establishing the electrical connection between these heating units 150. When the respective heating unit 150 is pivoted, its electric contact 181 is disconnected from the electric contact 182 of the neighbouring heating unit 150, thereby interrupting the electrical connection between these heating units 150.

[0078] The present invention therefore provides a mechanism, which allows to pivot the heating units 150 out of their position in the frame structure 160, such that pivoted units 150 can easily be accessed, in particular in order to facilitate maintenance of the heating units 150. After accessing the pivoted unit 150, e.g. after performing maintenance, the heating unit 150 can easily be pivoted back again to its position in the frame structure 160. The present invention therefore allows to easily remove and reassemble the heating units 150 with low effort in a timesaving and cost-saving manner. The heating units 150 especially do not need to be completely dismantled and moved to the ground, but can be pivoted, swung or folded up. Particularly, a crane is not needed for removing and reassembling the heating units 150.

Claims

Patent Claims1. A furnace (100) for performing a chemical process and / or for heating a process medium, wherein the furnace (100) comprises a number of walls (110, 120, 125) defining an interior volume (130) of the furnace (100), wherein at least one wall (110) of the number of walls comprises a frame structure (160) and at least one furnace component (150), particularly comprising heating means for heating the interior (103) volume of the furnace (100), provided in the frame structure (160), said at least one wall (110) defining a respective outer wall plane (190); wherein at least one of the at least one furnace component (150) is configured to be assembled into the corresponding wall (110) by means of a pivot mechanism (240) such that the respective furnace component (150) can be pivoted out of and back into the wall plane (190) of the respective wall (110) of the furnace.

2. The furnace according to claim 1 , wherein the pivot mechanism (240) comprises: a first support element (210) being provided at the respective furnace component (150), especially at an exterior surface (151) of the respective furnace component (150); and a second support element (220) being provided at the respective wall (110) external to the respective furnace component (150); wherein the first support element (210) is configured to be pivoted relative to the second support element (220).

3. The furnace according to claim 2, wherein the first support element (210) is attached to the second support element (220) or wherein a pivoting element (230) is provided and configured to be attached to the first support element (210) and the second support element (220).

4. The furnace according to claim 2 or 3, wherein the second support element (220) is provided at the frame structure (160) and / or at a support structure of the furnace wall for supporting the at least one of the at least one furnace component (150) and / or at another furnace component than the respective furnace component (150), particularly at a furnace component adjacent to the respective furnace component (150).

5. The furnace according to any one of the claims 2 to 4, wherein the first support element (210) is provided as at least one first bolt element fastened to the respective furnace component (150), wherein the pivoting element (230) is configured to be mounted on this atleast one first bolt element, and / or wherein the second support element (220) is provided as at least one second bolt element, wherein the pivoting element (230) is configured to be mounted on this at least one second bolt element.

6. The furnace according to any one of the preceding claims, wherein a part of the respective furnace component (150) is arranged behind a support structure of the furnace wall for supporting the at least one furnace (150) and wherein the pivot mechanism (240) is configured such that the respective furnace component (150) can be pivoted relative to this support structure of the furnace wall.

7. The furnace according to any one of the preceding claims, wherein the respective furnace component (150) comprises a flange element (155), wherein the respective furnace component (150) is configured to be detachably fastened to the frame structure (160) and / or to a neighbouring furnace component by means of this flange element (155), wherein the first support element (210) of the furnace of claim 2 is particularly provided at or on this flange element (155).

8. The furnace according to any one of the preceding claims, when referring back to claim 2, wherein the pivoting element (230) is configured to be detachably attached to the second support element (220) such that the pivoted respective furnace component (150) can be removed from the respective wall (110) and / or frame structure (160) after the pivoting element (230) has been detached or decoupled from the second support element (220).

9. The furnace according to any one of the preceding claims, wherein the respective furnace component (150) is configured to be electrically connected with a neighbouring furnace component by means of electrical connection means (180), wherein the electrical connection means (180) are configured to disconnect the respective furnace component (150) from the neighbouring furnace component when the respective furnace component (150) is pivoted by means of the pivot mechanism (240).

10. The furnace according to any one of the preceding claims, wherein at least one side surface (153) of the respective furnace component (150) is formed corresponding to a trajectory (250) of a pivoting movement of the respective furnace component (150) when the respective furnace component (150) is pivoted by means of the pivot mechanism (240) such that the respective side surface (153) abuts on a correspondingly formed side surface of a furnace component adjacent to the respective furnace component (150) or of the framestructure (160) when the respective furnace component (150) is pivoted into the respective wall plane (180).11 . The furnace according to any one of the preceding claims, wherein the at least one furnace component (150) is provided as at least one electrical heating unit.

12. The furnace according to claim 10, wherein each electrical heating unit (150) comprises a heating element and / or an insulation element and / or a panel element.

13. A method for accessing, particularly maintaining, a furnace component (150) of a furnace (100) according to any one of the preceding claims, comprising the steps of: pivoting the respective furnace component (150) by means of the pivot mechanism (240) out of the respective wall plane (190) of the respective wall (110) of the furnace; and accessing, particularly maintaining, the pivoted respective furnace component (150).

14. The method according to claim 13 for accessing, particularly maintaining, a furnace component (150) of a furnace (100) according to claim 2, comprising the steps of: attaching the pivoting element (230) to the first support element (210) and the second support element (220); pivoting the respective furnace component (150) by means of the pivoting element (230) out of the respective wall plane (190) of the respective wall (110) of the furnace; and accessing, particularly maintaining, the pivoted respective furnace component (150).

15. The method according to claim 14, further comprising: pivoting the respective furnace component (150) by means of the pivoting element (230) back into the respective wall plane (190) of the respective wall (110) of the furnace after having accessed, particularly maintained, the respective furnace component (150); and detaching the pivoting element (160) from the first support element (210) and the second support element (220).

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