Bearing arrangement for reforming tube

Abstract

A reforming tube (208A, 208B, 308A, 308B) for a steam reformer or an ammonia cracker is provided. The reforming tube comprises a pressure-bearing cylindrical jacketed tube (210A, 210B, 310A, 310B) arranged to contain a catalyst (220A, 220B, 320A, 320B), an inlet end of the jacketed tube connectable to a reactant feed line (204A, 204B, 304A, 304B), a reactant feed line connectable to a reactant feed system (202A, 202B, 302), an outlet end of the jacketed tube connectable to a product discharge line (216A, 216B, 316A, 316B), and an inlet end of the jacketed tube connectable to a product gas manifold (218, 218). 318) of the product discharge line. The jacketed tube is supported in the direction of its longitudinal axis by a fixed-floating bearing arrangement to allow thermal expansion of the jacketed tube in the longitudinal direction. A fixed bearing (214A, 214B, 314A, 314B) is located at the outlet end of the outer jacketed tube, and a floating bearing (206A, 206B, 306A, 306B) is located at the inlet end of the outer jacketed tube.

Description

Technical Field

[0001] The present invention generally relates to reformer tubes and piping systems for steam reformers or ammonia crackers; more specifically, the present invention relates to a reformer tube for a steam reformer or ammonia cracker having a bearing arrangement that absorbs thermal expansion. The present invention also relates to a method for steam reforming a hydrocarbon-containing feed stream with steam to form a synthesis gas stream containing carbon monoxide and hydrogen, and to a method for cracking an ammonia feed stream to form a product gas stream containing hydrogen and nitrogen. Background Art

[0002] In the synthesis gas production based on steam-methane, a mixture of pre-superheated natural gas and steam is fed to a separate cracking tube arranged in a cracking tube furnace via a piping system for feed distribution. The operating temperature of the piping system can be up to 650°C, thereby causing considerable thermal expansion. The reactant feed line or manifold have an outlet (also referred to as a hairpin bend or pigtail bend) for each connected reforming tube to absorb thermal expansion. Typically, the reforming tube is connected to the corresponding outlet via a pipe having a diameter identical to or smaller than the reactant feed line or distributor itself. During operation, the reactant feed line and the reforming tube experience elongation in the vertical direction due to thermal expansion, which also changes the position of the reactant feed line or manifold in the vertical direction. During operation, the reforming tube experiences thermal expansion (dA) (for example, upward thermal linear expansion) of up to 300 millimeters (mm). Due to arrangement as described above, this upward expansion can be absorbed by the reactant distributor.

[0003] The stress and elongation caused by thermal expansion (d comp ) is usually absorbed or compensated by the flexible design of the outlet (i.e. hairpin bend or pigtail bend). The resulting elongation (d comp ) is the difference between the elongation of the reactant feed line (dB) and the elongation of the reforming tube, and is expressed as follows:

[0004] d comp =dA-dB

[0005] The resulting elongation (d comp ) can be about 70% to 30% of the elongation of the reformer tubes, depending on the steam reformer size.

[0006] The thermal linear expansion and displacement of the reactant feed lines and / or manifolds caused by the operating temperature of the system, as well as the thermal linear expansion and displacement of the feeders and the thermal linear expansion of the reformer tubes caused by the operating temperature of the system, are addressed separately by existing systems. One existing system includes a combination of floating bearings and fixed bearings in the reactant feed lines / distributors. The floating bearings can be guides and cantilever hangers or similar pipe supports. Another existing solution uses pipe routing with correspondingly large expansion elbows to provide an outlet that is as flexible as possible. However, short pipe routing minimizes heat loss in the system and reduces the necessary material input. The outlet (e.g., the reactant distribution system) is one of the main sources of heat loss in the entire synthesis gas plant. Due to the necessary expansion elbows or loops at the outlet, the overall height and / or width of the piping system is high, depending on the configuration of the piping system. The piping system is usually placed in the "penthouse" (i.e., the upper part with a roof) of the reformer, which is usually provided for weather protection and to reduce heat loss due to wind effects. Therefore, in addition to the steel structure, other piping systems (such as the piping system for fuel gas and the piping system for combustion air) must also be made longer according to the resulting distance. This also increases the heat loss of other distribution systems and the construction cost of the entire structure.

[0007] Therefore, it is necessary to solve the above technical shortcomings in the prior art and provide a reformer tube with high efficiency in absorbing thermal expansion for the reformer.

[0008] Furthermore, since ammonia cracking is being discussed as a means of providing hydrogen near potential consumers, corresponding apparatus and methods need to be proposed. It has been discovered that apparatus typically used for steam reforming (e.g., reformer tubes and / or reforming furnaces) can be operated as ammonia crackers with minor modifications. Therefore, for the purposes of this specification, the terms reformer, reformer furnace, and reformer tube should also be understood to refer to apparatus and / or devices that can also be used in the context of ammonia cracking. Summary of the Invention

[0009] The present invention seeks to provide a reformer tube for a steam reformer or ammonia cracker, where capital costs dominate overall economics. The present invention aims to provide a solution that at least partially overcomes the problems encountered in the prior art by utilizing a combination of rigid connections and floating bearings to absorb the stresses caused by thermal expansion of the reformer tube's pressurized cylindrical jacketed tube in the radial direction. Thermal linear expansion of the reformer tube is fully transferred from the product discharge line to the connected reactant feed line and compensated by the reactant feed line via the floating bearings. Consequently, additional expansion elbows in the reactant feed line are avoided, thereby reducing the length of the reformer tube in the synthesis gas plant.

[0010] The objects of the invention are achieved by the solutions provided in the appended independent claims. Advantageous embodiments of the invention are further defined in the dependent claims.

[0011] According to a first aspect, a reforming tube for a steam reformer or an ammonia cracker according to the present invention comprises:

[0012] (a) a pressurized cylindrical jacketed tube arranged to contain a catalyst as a bulk catalyst, a catalyst bed of catalyst particles, a structured packing, a honeycomb catalyst, or a combination thereof;

[0013] (b) an inlet end of a pressure-containing cylindrical jacketed tube, the inlet end being connectable to a reactant feed line;

[0014] (c) a reactant feed line, which can be connected to a reactant feed system;

[0015] (d) an outlet end of a pressure-containing cylindrical jacketed tube, the outlet end being connectable to a product discharge line;

[0016] (e) a product discharge line connectable to a product gas manifold;

[0017] in

[0018] (f) the pressure-containing cylindrical jacketed tube is supported in the direction of its longitudinal axis by a fixed-floating bearing arrangement to allow for thermal expansion of the pressure-containing cylindrical jacketed tube in the longitudinal direction,

[0019] in

[0020] (g) A fixed bearing is located at the outlet end of the outer pressure-containing cylindrical jacketed tube, and a floating bearing is located at the inlet end of the outer pressure-containing cylindrical jacketed tube.

[0021] The advantage of the reforming tube and the bearing arrangement of the reforming tube according to the present invention is that the rigid connection is combined with the floating bearing to absorb the stress caused by the thermal expansion of the pressure-bearing cylindrical jacket of the reforming tube in the axial (longitudinal) and / or radial directions. The thermal linear expansion of the reforming tube is completely transferred from the product discharge line to the connected reactant feed line and is compensated by the reactant feed line through the floating bearing. As a result, additional expansion bends (i.e., hairpin bends, pigtail bends) in the reactant feed line are avoided, thereby reducing the overall height or size of the entire synthesis gas plant system, and also reducing heat losses by shortening the transfer lines, i.e., the reactant feed line and the product discharge line. In addition, since the force is transmitted vertically to the reactant feed line in large quantities via the product discharge line, the bending forces, loads and stresses acting on the product discharge line are reduced, which leads to an increase in the expected service life of the reformer and increased operational reliability.

[0022] According to a second aspect, the present invention provides a reforming furnace comprising a floor, a ceiling, and side walls forming a furnace interior, wherein a plurality of reforming tubes as described above are arranged within the furnace interior and heated by burners.

[0023] According to a third aspect, the present invention provides a method for steam reforming a hydrocarbon-containing feed stream with steam to form a synthesis gas stream containing carbon monoxide and hydrogen, the method comprising the steps of:

[0024] (a) providing a plurality of reforming tubes as described above in a reforming furnace;

[0025] (b) connecting the reactant feed lines of the reforming tubes to a common reactant feed system;

[0026] (c) connecting the product discharge lines of the reforming tubes to a common product gas manifold;

[0027] (d) injecting a hydrocarbon-containing feed stream through the reactant feed system and reactant feed line of the reforming tube;

[0028] (e) reacting a hydrocarbon-containing feed stream with steam in a reforming tube under steam reforming conditions to form a crude synthesis gas stream;

[0029] (f) discharging a crude synthesis gas stream from the reformer tubes via a product discharge line and a common product gas manifold;

[0030] (g) feeding the crude synthesis gas stream to at least one further workup, separation, purification or conditioning step and discharging the purified or conditioned synthesis gas stream and / or its constituents hydrogen and / or carbon monoxide.

[0031] According to a fourth aspect, the present invention provides a process for cracking an ammonia feed stream with steam to form a product gas stream containing hydrogen and nitrogen, the process comprising the steps of:

[0032] (a) providing a plurality of reforming tubes according to claims 1 to 7 in a reforming furnace (200, 300) according to claims 8 to 9;

[0033] (b) connecting the reactant feed lines (204A, 204B, 304A, 304B) of the reforming tubes (208A, 208B, 308A, 308B) to a common reactant feed system;

[0034] (c) connecting the product discharge lines (216A, 216B, 316A, 316B) of the reforming tubes (208A, 208B, 308A, 308B) to a common product gas manifold;

[0035] (d) injecting an ammonia feed stream through the reactant feed system (202A, 202B, 302) and reactant feed lines (204A, 204B, 304A, 304B) of the reforming tubes (208A, 208B, 308A, 308B);

[0036] (e) reacting an ammonia feed stream in reforming tubes (208A, 208B, 308A, 308B) under ammonia cracking conditions to form a product gas stream containing hydrogen and nitrogen;

[0037] (f) withdrawing a product gas stream from the reformer tubes (208A, 208B, 308A, 308B) via product discharge lines (216A, 216B, 316A, 316B) and a common product gas manifold; and

[0038] (g) feeding the product gas stream to at least one further workup, separation, purification or conditioning step, discharging the purified product gas stream and / or its components hydrogen and / or nitrogen.

[0039] The advantage of the reforming tube and the bearing arrangement of the reforming tube according to the present invention is that the rigid connection is combined with the floating bearing to absorb the stress caused by the thermal expansion of the pressure-bearing cylindrical jacket of the reforming tube in the axial (longitudinal) and / or radial directions. The thermal linear expansion of the reforming tube is completely transferred from the product discharge line to the connected reactant feed line and is compensated by the reactant feed line through the floating bearing. As a result, additional expansion bends (i.e., hairpin bends, pigtail bends) in the reactant feed line are avoided, thereby reducing the overall height or size of the entire synthesis gas plant system, and also reducing heat losses by shortening the transfer lines, i.e., the reactant feed line and the product discharge line. In addition, since the force is transmitted vertically to the reactant feed line in large quantities via the product discharge line, the bending forces, loads and stresses acting on the product discharge line are reduced, which leads to an increase in the expected service life of the reformer and increased operational reliability.

[0040] Embodiments of the present invention eliminate the above-mentioned disadvantages of the prior known methods by providing a rigid connection in the reformer tube in combination with a fixed-floating bearing arrangement for absorbing stresses due to thermal expansion in the reformer tube.

[0041] Other aspects, advantages, features and purposes of the present invention will become apparent from the accompanying drawings and detailed description of exemplary embodiments taken in conjunction with the accompanying claims. It will be appreciated that the features of the present invention are susceptible to being combined in various combinations without departing from the scope of the invention as defined by the accompanying claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] The above summary of the invention and the following detailed description of exemplary embodiments are better understood when read in conjunction with the accompanying drawings. To illustrate the present invention, exemplary configurations of the present invention are shown in the accompanying drawings. However, the present invention is not limited to the specific methods and tools disclosed herein. In addition, it should be understood by those skilled in the art that the drawings are not drawn to scale. Where possible, identical elements are indicated by identical numbers. Embodiments of the present invention will now be described, by way of example only, with reference to the following figures, in which:

[0043] Figure 1A-1D is a schematic diagram of the arrangement and configuration of reforming tubes in a reforming furnace according to the prior art;

[0044] Figure 2 is a schematic diagram of a reformer having a dual reactant feed system according to an embodiment of the present invention;

[0045] Figure 3 is a schematic diagram of a reformer having a single reactant feed system according to an embodiment of the present invention. DETAILED DESCRIPTION

[0046] The following detailed description illustrates embodiments of the present invention and ways in which it can be implemented. Although some modes of carrying out the invention have been disclosed, those skilled in the art will recognize that other embodiments for carrying out or practicing the invention are also possible.

[0047] Steam reforming conditions or ammonia cracking conditions are known to those skilled in the art from the prior art. These are the physicochemical conditions that achieve a measurable, preferably industrially relevant conversion of hydrocarbons into a synthesis gas product, or the conversion of ammonia into a product gas containing hydrogen and nitrogen. For example, in the context of steam reforming, important parameters include adjusting a suitable steam reforming inlet temperature, typically about 1000° C., and adding steam to the hydrocarbon-containing input gas and thereby adjusting the steam / carbon ratio (S / C ratio). Typical values ​​for the S / C ratio are between 1.5 mol / mol and 3.5 mol / mol. Typical steam reforming inlet temperatures are up to 700° C. and typically in the range of 550° C. and 650° C. The necessary adjustments of these conditions according to the respective operational requirements will be made by those skilled in the art on the basis of routine experimentation. Any specific reaction conditions disclosed herein can be used as a guide, but they should not be considered as limiting the scope of the invention.

[0048] A fluid connection between two zones of a device or apparatus or reformer according to the invention is to be understood as meaning any type of connection that makes it possible for a fluid (e.g. a gas stream) to flow from one of the two zones to the other, regardless of any intervening zones or components. In particular, a direct fluid connection is to be understood as meaning any type of connection that makes it possible for a fluid (e.g. a gas stream) to flow directly from one of the two zones to the other, without intervening further zones or components other than the purely transport operation and the necessary means for this (e.g. pipes, valves, pumps, compressors, tanks). An example is a pipeline that leads directly from one of the two zones to the other.

[0049] Means is to be understood as meaning something that enables or contributes to the achievement of an objective. In particular, means for carrying out a particular method step is to be understood as meaning any physical item that a person skilled in the art would consider to be capable of carrying out that method step. For example, a person skilled in the art would consider means for introducing or removing a material flow to include any transport and delivery devices, i.e., for example, pipes, pumps, compressors, valves, which would appear necessary or obvious to the person skilled in the art for carrying out that method step based on his or her knowledge of the art.

[0050] For the purposes of this specification, steam is to be understood as synonymous with water vapor, unless otherwise indicated in individual cases. In contrast, the term "water" refers to water in its liquid state, unless otherwise indicated in individual cases.

[0051] In the context of the present invention, a reactant feed line or distributor is connected to one or more reforming tubes in series or in a row via a single outlet with a maximum 90° change of direction. Thermal linear expansion of the reforming tubes is transferred from the outlet to the connected reactant feed line and compensated for by the corresponding floating bearings of the reactant feed line. The reactant feed line or distributor has only one fixed bearing in the axial (longitudinal) direction of the distributor.

[0052] According to a first aspect, the present invention provides a reforming tube for a reformer or an ammonia cracker, the reforming tube comprising:

[0053] (a) a pressurized cylindrical jacketed tube arranged to contain a catalyst as a bulk catalyst, a catalyst bed of catalyst particles, a structured packing, a honeycomb catalyst, or a combination thereof;

[0054] (b) an inlet end of a pressure-containing cylindrical jacketed tube, the inlet end being connectable to a reactant feed line;

[0055] (c) a reactant feed line, which can be connected to a reactant feed system;

[0056] (d) an outlet end of a pressure-containing cylindrical jacketed tube, the outlet end being connectable to a product discharge line;

[0057] (e) a product discharge line connectable to a product gas manifold;

[0058] in

[0059] (f) the pressure-containing cylindrical jacketed tube is supported in the direction of its longitudinal axis by a fixed-floating bearing arrangement to allow for thermal expansion of the pressure-containing cylindrical jacketed tube in the longitudinal direction,

[0060] in

[0061] (g) A fixed bearing is located at the outlet end of the outer pressure-containing cylindrical jacketed tube, and a floating bearing is located at the inlet end of the outer pressure-containing cylindrical jacketed tube.

[0062] The advantage of the reforming tube and the bearing arrangement of the reforming tube according to the present invention is that the rigid connection is combined with the floating bearing to absorb the stress caused by the thermal expansion of the pressure-bearing cylindrical jacket of the reforming tube in the axial (longitudinal) and / or radial directions. The thermal linear expansion of the reforming tube is completely transferred from the product discharge line to the connected reactant feed line and is compensated by the reactant feed line through the floating bearing. As a result, additional expansion bends (i.e., hairpin bends, pigtail bends) in the reactant feed line are avoided, thereby reducing the overall height or size of the entire synthesis gas plant system, and also reducing heat losses by shortening the transfer lines, i.e., the reactant feed line and the product discharge line. In addition, since the force is transmitted vertically to the reactant feed line in large quantities via the product discharge line, the bending forces, loads and stresses acting on the product discharge line are reduced, which leads to an increase in the expected service life of the reformer and increased operational reliability.

[0063] Optionally, the reactant feed line has only one single change of direction, preferably only one single change of direction of 90°. Although this increases the number of expansion elbows by one compared to a completely straight connection, the arrangement is still robust and serves to reduce the built height of the steam reformer or ammonia cracker and to reduce the length of the connecting line and the heat losses associated therewith.

[0064] Alternatively, the product discharge line has no directional change and its longitudinal axis coincides with or is aligned with the longitudinal axis of the pressure-bearing cylindrical jacketed tube. In this way, the expansion stresses occur primarily one-dimensionally in the direction of the longitudinal axis of the pressure-bearing cylindrical jacketed tube and can be accounted for in a simple manner in the construction of the reformer and its frame.

[0065] Optionally, the floating bearing is designed as a rolling bearing, a ball bearing, a plain bearing or a floating support bearing.

[0066] Optionally, the floating and fixed bearings are designed to absorb stresses caused by thermal expansion of the pressure-bearing cylindrical jacket tube in the radial direction. While the longitudinal length increase of the reformer tube during heat-up of the reformer furnace is dominant, the radial length increase is much smaller, but can still be significant. Therefore, this embodiment offers particular advantages in managing thermal stresses in both the longitudinal and radial directions.

[0067] Alternatively, the inlet ends of several jacketed tubes can be connected to a common reactant feed line. This further reduces the length of the connecting lines and the heat losses associated therewith.

[0068] Alternatively, the product discharge line forms a right angle with the product gas manifold when connected. While this increases the number of expansion elbows by one compared to a completely straight connection, the arrangement is still robust and serves to reduce the overall height of the steam reformer or ammonia cracker, and to reduce the length of the connecting line and the associated heat losses.

[0069] According to a second aspect, the present invention provides a reforming furnace comprising a floor, a ceiling, and side walls forming a furnace interior, wherein a plurality of reforming tubes as described above are arranged within the furnace interior and heated by burners.

[0070] Optionally, the plurality of reforming tubes are arranged in rows, preferably in parallel rows, wherein every two adjacent reforming tubes in a row are connected to a common reactant feed line. This further reduces the length of the connecting lines and the heat losses associated therewith.

[0071] Alternatively, the present invention provides the use of a reformer tube and / or reformer as described above for steam reforming a hydrocarbon-containing feed stream with steam into a raw synthesis gas stream or for cracking an ammonia feed stream into a product gas stream containing hydrogen and nitrogen.

[0072] According to a third aspect, the present invention provides a method for steam reforming a hydrocarbon-containing feed stream with steam to form a synthesis gas stream containing carbon monoxide and hydrogen, the method comprising the steps of:

[0073] (a) providing a plurality of reforming tubes as described above in a reforming furnace;

[0074] (b) connecting the reactant feed lines of the reforming tubes to a common reactant feed system;

[0075] (c) connecting the product discharge lines of the reforming tubes to a common product gas manifold;

[0076] (d) injecting a hydrocarbon-containing feed stream through the reactant feed system and reactant feed line of the reforming tube;

[0077] (e) reacting a hydrocarbon-containing feed stream with steam in a reforming tube under steam reforming conditions to form a crude synthesis gas stream;

[0078] (f) discharging a stream of raw synthesis gas from the reformer tubes via a product discharge line and a common product gas manifold; and

[0079] (g) feeding the crude synthesis gas stream to at least one further workup, separation, purification or conditioning step and discharging the purified or conditioned synthesis gas stream and / or its constituents hydrogen and / or carbon monoxide.

[0080] According to a fourth aspect, the present invention provides a process for cracking an ammonia feed stream with steam to form a product gas stream containing hydrogen and nitrogen, the process comprising the steps of:

[0081] (a) providing a plurality of reforming tubes according to claims 1 to 7 in a reforming furnace (200, 300) according to claims 8 to 9;

[0082] (b) connecting the reactant feed lines (204A, 204B, 304A, 304B) of the reforming tubes (208A, 208B, 308A, 308B) to a common reactant feed system;

[0083] (c) connecting the product discharge lines (216A, 216B, 316A, 316B) of the reforming tubes (208A, 208B, 308A, 308B) to a common product gas manifold;

[0084] (d) injecting an ammonia feed stream through the reactant feed system (202A, 202B, 302) and reactant feed lines (204A, 204B, 304A, 304B) of the reforming tubes (208A, 208B, 308A, 308B);

[0085] (e) reacting an ammonia feed stream in reforming tubes (208A, 208B, 308A, 308B) under ammonia cracking conditions to form a product gas stream containing hydrogen and nitrogen;

[0086] (f) withdrawing a product gas stream from the reformer tubes (208A, 208B, 308A, 308B) via product discharge lines (216A, 216B, 316A, 316B) and a common product gas manifold; and

[0087] (g) feeding the product gas stream to at least one further workup, separation, purification or conditioning step, discharging the purified product gas stream and / or its components hydrogen and / or nitrogen.

[0088] The advantage of the reforming tube with a fixed-floating bearing arrangement provided in the method according to the present invention is that the rigid connection is combined with the floating bearing to absorb the stress caused by thermal expansion of the pressure-bearing cylindrical jacket of the reforming tube in the axial (longitudinal) and / or radial directions. The thermal linear expansion of the reforming tube is completely transferred from the product discharge line to the connected reactant feed line and is compensated by the reactant feed line via the floating bearing. As a result, additional expansion bends (i.e., hairpin bends, pigtail bends) in the reactant feed line are avoided, thereby reducing the overall height or size of the entire synthesis gas plant system, and also reducing heat losses by shortening the transfer lines, i.e., the reactant feed line and the product discharge line. In addition, since the forces are largely vertically transmitted to the reactant feed line via the product discharge line, the bending forces, loads, and stresses acting on the product discharge line are reduced, which leads to an increase in the expected service life of the reformer and increased operational reliability.

[0089] Embodiments of the present invention substantially eliminate or at least partially address the above-mentioned technical disadvantages of the prior art by providing a rigid connection in the reformer tube in combination with a floating bearing arrangement for absorbing stresses due to thermal expansion in the reformer tube.

[0090] Detailed description with accompanying drawings

[0091] Figure 1A-1D is a schematic diagram illustrating the arrangement and configuration of reforming tubes in a reforming furnace 100 according to the prior art. The reforming furnace 100 can be arranged in various arrangements, such as a radiant wall arrangement, a top-fired arrangement, a bottom-fired arrangement, and a stepped wall arrangement.

[0092] Figure 1A Shown is a reformer 100 with exemplary two reforming tubes, the reformer being arranged into a radiant wall arrangement, comprising a feed distribution system 102A and 102B, feed lines 104A and 104B, reforming tubes 106A and 106B, product collecting lines 110A and 110B, and a feed manifold 112. Feed lines 104A and 104B are connected to the inlet of each reforming tube 106A and 106B. Feed lines 104A and 104B are arranged to be at an angle to reforming tubes 106A and 106B. Feed distribution system 102A and 102B is connected to feed lines 104A and 104B by a pipe having a diameter less than that of feed lines 104A and 104B to be delivered to reforming tubes 106A and 106B. The reforming tubes 106A and 106B are connected to the product collecting lines 110A and 110B via tubes having a smaller diameter than the product collecting lines 110A and 110B. The product collecting lines 110A and 110B have outlets and are connected to a product manifold 112.

[0093] Figure 1BShown is a reformer 100 with exemplary two reforming tubes, the reformer being arranged as a top-fired arrangement, comprising a feed distribution system 102A and 102B, feed lines 114A and 114B, reforming tubes 106A and 106B, product collecting lines 110A and 110B, and a feed manifold 112. Feed lines 114A and 114B are connected to the inlet of each reforming tube 106A and 106B. Feed lines 114A and 114B include one or more elbows. Feed distribution system 102A and 102B is connected to feed lines 114A and 114B by a pipe having a diameter less than that of feed lines 114A and 114B to be delivered to reforming tubes 106A and 106B. The reforming tubes 106A and 106B are connected to the product collecting lines 110A and 110B via tubes having a smaller diameter than the product collecting lines 110A and 110B. The product collecting lines 110A and 110B have outlets and are connected to a product manifold 112.

[0094] Figure 1C Shown is a reformer 100 with exemplary two reforming tubes, which is arranged into a bottom-burning arrangement and includes a feed distribution system 116A, feed lines 118A and 118B, reforming tubes 106A and 106B, product collecting lines 110A and 110B, and feed manifolds 120A and 120B. Feed lines 118A and 118B are connected to the inlet of each reforming tube 106A and 106B. Feed lines 118A and 118B include elbows. Feed distribution system 116A is connected to feed lines 118A and 118B by a pipe less than feed lines 118A and 118B in diameter. Reforming tubes 106A and 106B are connected to product collecting lines 110A and 110B via a pipe less than product collecting lines 110A and 110B in diameter. Product collecting lines 110A and 110B are U-shaped in the example and have outlets and are connected to product manifolds 120A and 120B.

[0095] Figure 1DShown is a reformer 100 with exemplary two reforming tubes, the reformer being arranged into a stepped wall arrangement, comprising a feed distribution system 122A and 122B, feed lines 124A and 124B (which are U-shaped in the example), reforming tubes 106A and 106B, product collecting lines 110A and 110B, and a feed manifold 126A. Feed lines 124A and 124B are connected to the inlet of each reforming tube 106A and 106B. Feed lines 124A and 124B comprise hairpin bends or pigtail bends. Reforming tubes 106A and 106B are connected to feed lines 124A and 124B by a pipe having a diameter less than that of feed lines 124A and 124B. Reforming tubes 106A and 106B are connected to product collecting lines 110A and 110B via tubes having a smaller diameter than that of product collecting lines 110A and 110B. Product collecting lines 110A and 110B have outlets and are connected to product manifold 126A.

[0096] In an example, a feed distribution system (e.g., 102A and 102B, 116A, 122A, and 122B) is used to feed natural gas or a superheated mixture of methane and steam to individual reforming tubes 106A and 106B arranged in the reformer 100. The operating temperature of the feed lines can be as high as 650°C, which results in considerable thermal expansion. The piping system (i.e., the feed lines and product collection lines) can absorb the thermal expansion.

[0097] During operation, the feed lines (e.g., 104A and 104B, 114A and 114B, 118A and 118B, and 124A and 124B) of various configurations (i.e., radiant wall, top-fired wall, bottom-fired wall, and stepped wall) in the reformer 100 undergo vertical elongation due to thermal expansion. Reformer tubes 106A and 106B change the vertical position of product collection lines 110A and 110B. Reformer tubes 106A and 106B experience thermal expansion (i.e., upward thermal linear expansion) of up to 300 millimeters (mm). Due to this configuration, product collection lines 110A and 110B absorb the upward thermal expansion. The operating temperature of the reformer 100 causes thermal linear expansion of the various arrangements of reactant feed lines (e.g., 104A and 104B, 114A and 114B, 118A and 118B, and 124A and 124B) of the reformer 100 and displacement of the feed and / or product manifolds (e.g., 112, 120A and 120B, and 126A).

[0098] Figure 22 is a schematic diagram of a reformer furnace 200 having a dual reactant feed system according to an embodiment of the present invention. Reformer furnace 200 includes reactant feed systems 202A and 202B, reactant feed lines 204A and 204B, floating bearings 206A and 206B, reformer tubes 208A and 208B (including pressure-containing cylindrical jacketed tubes 210A and 210B), furnace interior 212, fixed bearings 214A and 214B, product exhaust lines 216A and 216B, and product gas manifold 218.

[0099] The reformer 200 may include a floor, a ceiling, or sidewalls to form a furnace interior 212, in which are disposed reactant feed systems 202A and 202B, reactant feed lines 204A and 204B, floating bearings 206A and 206B, reformer tubes 208A and 208B, pressure-bearing cylindrical jacketed tubes 210A and 210B, fixed bearings 214A and 214B, product exhaust lines 216A and 216B, and a product gas manifold 218. Optionally, the reformer 200 has one or more reformer tubes disposed within the furnace interior 212 and heated by a burner.

[0100] Pressure-bearing cylindrical jacket pipe 210A and 210B is arranged to accommodate catalyst 220A and 220B as the catalyst bed of block catalyst, catalyst particles, structured packing, honeycomb catalyst or its combination. The inlet end of pressure-bearing cylindrical jacket pipe (210A and 210B) can be connected to reactant feed pipeline 204A and 204B. Reactant feed pipeline 204A and 204B can be connected to reactant feed system 202A and 202B. Fixed bearing 214A and 214B is positioned at the outlet end of pressure-bearing cylindrical jacket pipe 210A and 210B, and floating bearing 206A and 206B is positioned at the inlet end of pressure-bearing cylindrical jacket pipe 210A and 210B. Floating bearing 206A and 206B can be designed as rolling bearing, ball bearing, sliding bearing or floating support bearing. The outlet ends of the pressurized cylindrical jacketed tubes 210A and 210B can be connected to product exhaust lines 216A and 216B. The product exhaust lines 216A and 216B can be connected to a product gas manifold 218. Optionally, the product exhaust lines 216A and 216B form a right angle with the product gas manifold 218 when connected.

[0101] The pressure-bearing cylindrical jacket tubes 210A and 210B are supported along their longitudinal axes using a fixed-floating bearing arrangement (i.e., floating bearings 206A and 206B and fixed bearings 214A and 214B) to accommodate thermal expansion of the pressure-bearing cylindrical jacket tubes 210A and 210B in the longitudinal direction. Optionally, the floating bearings 206A and 206B and the fixed bearings 214A and 214B absorb stress caused by thermal expansion of the pressure-bearing cylindrical jacket tubes 210A and 210B in the radial direction. Thermal linear expansion of the reforming tubes 208A and 208B is transferred to the reactant feed systems 202A and 202B and compensated for using the floating bearings 206A and 206B.

[0102] Alternatively, reactant feed lines 204A and 204B are connected to one or more reforming tubes in series or in a row via one or more separate outlets of reactant feed systems 202A and 202B. Alternatively, reactant feed lines 204A and 204B include only a single change in direction. This single change in direction can be 90°.

[0103] Alternatively, product discharge line (for example, 216A and 216B) does not have direction change, and its longitudinal axis coincides or aligns with the longitudinal axis of pressure-bearing cylindrical jacketed pipe 210A and 210B.Alternatively, the inlet end of one or more jacketed pipes can be connected to a shared reactant feed line.Alternatively, one or more reforming pipes are arranged in rows, preferably arranged in parallel rows.Alternatively, each of one or more adjacent reforming pipes in the row is connected to a shared reactant feed line.Reformer 200 steam reforms the hydrocarbon-containing feed stream to form a crude synthesis gas stream.

[0104] The advantages of the bearing arrangement of the reforming tubes (208A, 208B) according to the present invention are that a rigid connection in combination with a floating bearing (206A, 206B) is used to absorb stresses caused by thermal expansion of the pressure-bearing cylindrical jacketed tubes (210A, 210B) of the reforming tubes (208A, 208B) in the axial (longitudinal) and / or radial directions. The thermal linear expansion of the reforming tubes (208A, 208B) is fully transferred from the product discharge line (216A, 216B) to the connected reactant feed line and is compensated by the reactant feed line (204A, 204B) via the floating bearing (206A, 206B). As a result, additional expansion bends (i.e., hairpins, pigtails) in the reactant feed lines (204A, 204B) are avoided, thereby reducing the overall height or size of the entire device and also reducing heat losses by shortening the transfer lines, i.e., the reactant feed line and the product discharge line. In addition, since the forces are largely transmitted vertically to the reactant feed lines via the product discharge lines (216A, 216B), the bending moments, loads, and stresses acting on the product discharge lines (216A, 216B) are reduced, which results in an increased expected service life and increased operational reliability of the reformer 200.

[0105] Figure 3 is a schematic diagram of a reformer furnace 300 having a single reactant feed system according to an embodiment of the present invention. Reformer furnace 300 includes reactant feed system 302, reactant feed lines 304A and 304B, floating bearings 306A and 306B, reformer tubes 308A and 308B (including pressure-containing cylindrical jacketed tubes 310A and 310B), furnace interior 312, fixed bearings 314A and 314B, product exhaust lines 316A and 316B, and product gas manifold 318.

[0106] Pressure-bearing cylindrical jacket pipe 310A and 310B is arranged to accommodate catalyst 320A and 320B as the catalyst bed of block catalyst, catalyst particles, structured packing, honeycomb catalyst or its combination. The inlet end of pressure-bearing cylindrical jacket pipe (for example, 310A and 310B) can be connected to reactant feed line 304A and 304B. Reactant feed line 304A and 304B can be connected to reactant feed system 302. Fixed bearing 314A and 314B is positioned at the outlet end of pressure-bearing cylindrical jacket pipe 310A and 310B, and floating bearing 306A and 306B is positioned at the inlet end of pressure-bearing cylindrical jacket pipe 310A and 310B. Floating bearing 306A and 306B can be designed as rolling bearing, ball bearing, plain bearing or floating support bearing. The outlet ends of the pressurized cylindrical jacketed tubes 310A and 310B can be connected to product exhaust lines 316A and 316B. Product exhaust lines 316A and 316B can be connected to a product gas manifold 318. Optionally, product exhaust lines 316A and 316B form a right angle with the product gas manifold 318 when connected.

[0107] The pressure-bearing cylindrical jacket tubes 310A and 310B are supported along their longitudinal axes using a fixed-floating bearing arrangement (i.e., floating bearings 306A and 306B and fixed bearings 314A and 314B) to accommodate thermal expansion of the pressure-bearing cylindrical jacket tubes 310A and 310B in the longitudinal direction. Optionally, the floating bearings 306A and 306B and the fixed bearings 314A and 314B absorb stress caused by thermal expansion of the pressure-bearing cylindrical jacket tubes 310A and 310B in the radial direction. Thermal linear expansion of the reforming tubes 308A and 308B is transferred to the reactant feed system 302 and compensated for using the floating bearings 306A and 306B.

[0108] The advantage of the reforming tube with a fixed-floating bearing arrangement provided in this method is that the rigid connection is combined with the floating bearing to absorb the stress caused by the thermal expansion of the pressure-bearing cylindrical jacket tube of the reforming tube in the axial (longitudinal) and / or radial directions. The thermal linear expansion of the reforming tube is completely transferred from the product discharge line to the connected reactant feed line and is compensated by the reactant feed line through the floating bearing. Therefore, additional expansion bends (i.e., hairpin bends, pigtail bends) in the reactant feed line are avoided, thereby reducing the overall height or size of the entire device, and heat losses are also reduced by shortening the transfer lines, i.e., the reactant feed line and the product discharge line. In addition, since the force is transmitted vertically to the reactant feed line in large quantities via the product discharge line, the bending moment, load and stress acting on the product discharge line are reduced, which leads to an increase in the expected service life of the reformer and increased operational reliability.

[0109] Modifications may be made to the embodiments of the present invention described hereinbefore without departing from the scope of the present invention as defined by the appended claims. Expressions such as "comprises," "includes," "incorporates," "has," and "is" used to describe and claim the present invention are intended to be interpreted in a non-exclusive manner, i.e., allowing for the presence of items, components, or elements not expressly described. References to the singular are also to be construed as referring to the plural.

Claims

1. A reforming tube (208A, 208B, 308A, 308B) for a steam reformer or an ammonia cracker, the reforming tube comprising: (a) a pressurized cylindrical jacketed tube (210A, 210B, 310A, 310B) arranged to contain a catalyst (220A, 220B, 320A, 320B) that is a bulk catalyst, a catalyst bed of catalyst particles, a structured packing, a honeycomb catalyst, or a combination thereof; (b) an inlet end of the pressure-bearing cylindrical jacketed tube (210A, 210B, 310A, 310B), which inlet end can be connected to a reactant feed line (204A, 204B, 304A, 304B); (c) the reactant feed line (204A, 204B, 304A, 304B), which can be connected to the reactant feed system (202A, 202B, 302); (d) an outlet end of the pressure-bearing cylindrical jacketed tube (210A, 210B, 310A, 310B), which outlet end can be connected to a product discharge line (216A, 216B, 316A, 316B); (e) the product discharge line (216A, 216B, 316A, 316B), which can be connected to the product gas manifold (218, 318); in (f) the pressure-bearing cylindrical jacket tube (210A, 210B, 310A, 310B) is supported in the direction of its longitudinal axis by a fixed-floating bearing arrangement to allow thermal expansion of the pressure-bearing cylindrical jacket tube (210A, 210B, 310A, 310B) in the longitudinal direction, in (g) A fixed bearing (214A, 214B, 314A, 314B) is located at the outlet end of the outer pressure-bearing cylindrical jacket tube (210A, 210B, 310A, 310B), and a floating bearing (206A, 206B, 306A, 306B) is located at the inlet end of the outer pressure-bearing cylindrical jacket tube (210A, 210B, 310A, 310B).

2. The reforming tube (208A, 208B, 308A, 308B) according to claim 1, characterized in that The reactant feed lines (204A, 204B, 304A, 304B) have only one single change of direction, preferably only one single change of direction of 90°.

3. The reforming tube (208A, 208B, 308A, 308B) according to claim 1 or 2, characterized in that: The product discharge line (216A, 216B, 316A, 316B) has no change in direction and its longitudinal axis is coincident or aligned with the longitudinal axis of the pressure-containing cylindrical jacketed tube (210A, 210B, 310A, 310B).

4. The reforming tube (208A, 208B, 308A, 308B) according to any one of the preceding claims, characterized in that The floating bearing (206A, 206B, 306A, 306B) is designed as a rolling bearing, a ball bearing, a sliding bearing or a floating support bearing.

5. The reforming tube (208A, 208B, 308A, 308B) according to any one of the preceding claims, characterized in that The floating bearing (206A, 206B, 306A, 306B) and the fixed bearing (214A, 214B, 314A, 314B) are designed so that they can absorb stress caused by thermal expansion of the pressure-bearing cylindrical jacket tube (210A, 210B, 310A, 310B) in the radial direction.

6. The reforming tube (208A, 208B, 308A, 308B) according to any one of the preceding claims, characterized in that The inlet ends of several jacketed tubes can be connected to a common reactant feed line.

7. The reforming tube (208A, 208B, 308A, 308B) according to any one of the preceding claims, characterized in that The product discharge line (216A, 216B, 316A, 316B) forms a right angle with the product gas manifold (218, 318) in a connected state.

8. A reforming furnace (200, 300) comprising a bottom plate, a top plate and side walls forming a furnace interior, wherein a plurality of reforming tubes according to any one of claims 1 to 7 are arranged in the furnace interior and heated by a burner.

9. The reforming furnace (200, 300) according to claim 8, characterized in that The plurality of reforming tubes are arranged in rows, preferably in parallel rows, wherein every two adjacent reforming tubes in a row are connected to a common reactant feed line.

10. Use of the reformer tube (208A, 208B, 308A, 308B) according to claims 1 to 7 and / or the reformer (200, 300) according to claims 8 to 9 for steam reforming a hydrocarbon-containing feed stream with steam to form a raw synthesis gas stream.

11. Use of the reformer tube (208A, 208B, 308A, 308B) according to claims 1 to 7 and / or the reformer (200, 300) according to claims 8 to 9 for cracking an ammonia feed stream into a product gas stream containing hydrogen and nitrogen.

12. A method for steam reforming a hydrocarbon-containing feed stream with steam to form a synthesis gas stream containing carbon monoxide and hydrogen, the method comprising the steps of: (a) providing a plurality of reforming tubes according to claims 1 to 7 in a reforming furnace (200, 300) according to claims 8 to 9; (b) connecting the reactant feed lines (204A, 204B, 304A, 304B) of the reforming tubes (208A, 208B, 308A, 308B) to a common reactant feed system; (c) connecting the product discharge lines (216A, 216B, 316A, 316B) of the reforming tubes (208A, 208B, 308A, 308B) to a common product gas manifold; (d) injecting the hydrocarbon-containing feed stream through the reactant feed system (202A, 202B, 302) and reactant feed lines (204A, 204B, 304A, 304B) of the reforming tubes (208A, 208B, 308A, 308B); (e) reacting the hydrocarbon-containing feed stream with steam in the reforming tubes (208A, 208B, 308A, 308B) under steam reforming conditions to form a crude synthesis gas stream; (f) discharging the raw synthesis gas stream from the reforming tubes (208A, 208B, 308A, 308B) via the product discharge lines (216A, 216B, 316A, 316B) and the common product gas manifold; as well as (g) feeding the crude synthesis gas stream to at least one further workup, separation, purification or conditioning step, and discharging the purified or conditioned synthesis gas stream and / or its component hydrogen and / or carbon monoxide.

13. A process for cracking an ammonia feed stream with steam to form a product gas stream containing hydrogen and nitrogen, the process comprising the steps of: (a) providing a plurality of reforming tubes according to claims 1 to 7 in a reforming furnace (200, 300) according to claims 8 to 9; (b) connecting the reactant feed lines (204A, 204B, 304A, 304B) of the reforming tubes (208A, 208B, 308A, 308B) to a common reactant feed system; (c) connecting the product discharge lines (216A, 216B, 316A, 316B) of the reforming tubes (208A, 208B, 308A, 308B) to a common product gas manifold; (d) injecting the ammonia feed stream through the reactant feed system (202A, 202B, 302) and reactant feed lines (204A, 204B, 304A, 304B) of the reforming tubes (208A, 208B, 308A, 308B); (e) reacting the ammonia feed stream in the reforming tubes (208A, 208B, 308A, 308B) under ammonia cracking conditions to form a product gas stream containing hydrogen and nitrogen; (f) discharging the product gas stream from the reforming tubes (208A, 208B, 308A, 308B) via the product discharge lines (216A, 216B, 316A, 316B) and the common product gas manifold; as well as (g) feeding the product gas stream to at least one further workup, separation, purification or conditioning step, discharging the purified product gas stream and / or its components hydrogen and / or nitrogen.

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