Method for a metal flow reactor module and a produced module

Abstract

A method for forming a metal flow module includes: stacking a first metal plate together with a second metal plate, the first metal plate having opposed first and second major surfaces and one or more flow channels at least partially defined in one of the first major surfaces, the second metal plate having opposed first and second major surfaces, the plates being stacked together such that their respective first major surfaces face each other with a flux layer disposed between contacting portions of the respective first major surfaces, the contacting portions being defined as those portions of the respective first and second major surfaces that would contact each other in the absence of the flux layer; and then heating the plates together in a non-oxidizing atmosphere to thermally bond the contacting portions of the respective first major surfaces of the first and second metal plates. A resulting module is also disclosed.

Description

[0001] Cross-reference of related applications

[0002] This application claims priority to U.S. Provisional Application No. 63 / 003,273, filed March 31, 2020, pursuant to 35 U.S. SC §119, the entire contents of which are incorporated herein by reference. Technical Field

[0003] This disclosure relates to a method for producing metal flow modules that can be used in flow reactors, and more specifically, to an efficient and low-cost method for producing metal flow modules (particularly stainless steel flow modules characterized by through channels enclosed in a stainless steel module body). Background Technology

[0004] The large surface-to-volume ratios provided by micron-, millimeter-, and even smaller centimeter-scale channel geometries enhance mass and heat transfer, typically reducing reaction times from minutes or hours to seconds compared to conventional batch processing. This enhancement increases the reaction rate, thereby increasing the rate of product synthesis per reaction volume. Continuous flow reactors employing such channels are finding increasing widespread use in all scales of organic synthesis and other chemical processing applications.

[0005] The rapidly growing interest can be attributed to a range of advantages offered by such devices. Compared to traditional batch reactors, continuous flow reactors employing modules with channels at the micrometer and millimeter levels, or even smaller centimeters, typically exhibit enhanced heat and mass transfer, improved safety, and a higher level of controllability. Furthermore, multiple reaction steps, purification steps, and analyses can often be combined within a single continuous production unit.

[0006] Flow systems are typically assembled from relatively simple off-the-shelf components, such as polymer or metal tubing combined with standard connectors to join flow reactor modules together. These readily available and inexpensive components allow for limited design complexity for process intensification applications, particularly those requiring enhanced mass transfer or heat exchange. More sophisticated channel architectures can be provided within the flow reactor modules. Several structural elements have already been integrated into these devices, such as mixing structures, residence time channels, separation units, and interfaces for online analysis.

[0007] Commercially available flow reactor modules come in various pre-designed forms from a variety of inert materials, most commonly glass, stainless steel / Hastelloy metal, or silicon carbide ceramic. These modules can be manufactured using various techniques, such as micromachining, laser ablation, etching, laser sintering, and molding, but these methods are not particularly cost-effective. A lower-cost manufacturing method involves machining channels into one or both mating surfaces of a metal plate and then sealing the mating surfaces together with a compression elastic gasket. While less expensive, this approach has inherent limitations regarding operating temperature and pressure. A lower-cost manufacturing method is needed for high-performance flow reactors. Summary of the Invention

[0008] According to some aspects of this disclosure, a method for forming a metal flow module includes: stacking a first metal plate and a second metal plate together, the first metal plate having opposing first and second main surfaces and one or more flow channels at least partially defined in the first main surface, the second metal plate having opposing first and second main surfaces, the plates being stacked such that their respective first main surfaces face each other and a flux layer is disposed between contact portions of the respective first main surfaces, the contact portions being defined as those portions of the respective first and second main surfaces that would contact each other without the presence of flux; and heating the plates together in a non-oxidizing atmosphere to thermally bond the contact portions of the respective first main surfaces of the first and second metal plates.

[0009] In an embodiment, the second metal plate may also have one or more flow channels that are at least partially defined in its first main surface.

[0010] In this embodiment, the flux comprises carbide or nitride powder. Carbide powder or a mixture of carbide powders is most preferred, especially those containing boron carbide.

[0011] In one implementation, the plates are heated while being pressed together. Alternatively, the plates can be mechanically secured together before heating, for example by joining them with screws or bolts around their perimeter (or at a selected location around their perimeter and in the middle or center).

[0012] In one embodiment, before the plates are stacked together, at least a portion of the first primary surfaces of the first and second plates may be coated with a chemical-resistant coating. This portion corresponds (defined as aligning) the location of the flow channel. Alternatively, the plates may be heated together in a non-oxidizing atmosphere to thermally bond the contact portions of the respective first primary surfaces of the first and second metal plates, after which the flow channel is coated with a chemical-resistant coating. In either case, a carbide coating is desirable, preferably silicon carbide.

[0013] In one embodiment, the method further includes forming, for example, the one or more flow channels at least partially defined in the first main surface of the first plate by machining.

[0014] In other embodiments, a flow module is provided for use in a flow reactor or for other fluid processing, the flow module comprising: a first metal plate having opposing first and second main surfaces and one or more flow channels at least partially defined in the first main surface, and a second metal plate having opposing first and second main surfaces, the plates being bonded together by flux bonding such that their respective first main surfaces face each other.

[0015] In another embodiment, a flow module is provided for use in a flow reactor or for other fluid processing, the flow module comprising: a first metal plate having opposing first and second main surfaces and one or more flow channels at least partially defined in the first main surface, and a second metal plate having opposing first and second main surfaces, the plates being joined together by flux-assisted interdiffusion and / or by co-melting of the facing surfaces such that their respective first main surfaces face each other.

[0016] The methods and modules disclosed herein provide a low-cost approach to producing metal or stainless steel flow reactor modules. The inclusion of embedded fluid connectors facilitates user connection to the module, and the embedding process is also convenient, resulting in a robust seal between the connector and the consolidation plate. The methods and modules also provide flow reactor modules that can be sealed or encapsulated without the need for organic materials such as gaskets or O-rings, enabling the performance of high-temperature processing or reactions, or other processing or reactions incompatible with organic materials.

[0017] Other features and advantages of this document are set forth in the following detailed description, which will be readily apparent to those skilled in the art from the description, or will be recognized by practicing the various embodiments described herein, including the following detailed description, the claims, and the accompanying drawings.

[0018] It should be understood that the general description above and the detailed description below are merely exemplary and are intended to provide a general overview or framework for understanding the nature and characteristics of this disclosure and the appended claims.

[0019] The accompanying drawings are included to further understand the principles of this disclosure and are incorporated in and constitute a part of this specification. The drawings illustrate one or more embodiments of this disclosure and, together with the specification, serve to explain, for example, the principles and operation of this disclosure. It is to be understood that the various features of this disclosure disclosed in this specification and the accompanying drawings can be used in any and all combinations. As a non-limiting example, the various features of this disclosure can be combined with each other according to the following embodiments. Attached Figure Description

[0020] The following is a description of the accompanying drawings. For clarity and simplicity, the drawings are not necessarily drawn to scale, and some features and views may be shown enlarged or schematically.

[0021] In the attached diagram:

[0022] Figure 1 The flowchart illustrates optional steps in implementing the present disclosure;

[0023] Figure 2 The image is a digital photograph of a metal plate embodiment according to the present disclosure, the plate having one or more channels machined therein.

[0024] Figure 3 These are digital photographs of the implementation of the streaming module according to the present disclosure.

[0025] Figure 4 This is a digital photograph of another embodiment of the streaming module according to the present disclosure; and

[0026] Figure 5 This is a magnified digital photograph of the edge of an embodiment of the flow module according to the present disclosure, showing the seal between the first and second plates of the module. Detailed Implementation

[0027] Additional features and advantages are set forth in the following detailed description, some of which will be readily understood by those skilled in the art from the description, or will be recognized by the embodiments described in the following description, claims, and drawings.

[0028] As used herein, the term "and / or" when used to list two or more items means that any one of the listed items may be used alone, or any combination of two or more of the listed items may be used. For example, if a composition is described as containing components A, B, and / or C, the composition may contain only A; only B; only C; a combination of A and B; a combination of A and C; a combination of B and C; or a combination of A, B, and C.

[0029] In this document, relational terms, such as first and second, top and bottom, are used only to distinguish one entity or behavior from another, and do not necessarily require or imply any actual such relationship or order between such entities or behaviors.

[0030] Those skilled in the art, as well as those who utilize and use this disclosure, will make improvements to it. Therefore, it is to be understood that the embodiments shown in the accompanying drawings and described above are merely illustrative and not intended to limit the scope of this disclosure, which is defined by the appended claims and, in accordance with the principles of patent law, is to include the doctrine of equivalents.

[0031] For the purposes of this disclosure, the term "connected" (in all its forms: link, interlock, connected, etc.) generally refers to two components joined together directly or indirectly. Such a connection can naturally be static or naturally movable. Such a connection can be achieved by the two components and any additional intermediate elements, which together form a single unit or together with the two components form a single unit. Unless otherwise stated, such a connection can naturally be permanent, or naturally removable or detachable.

[0032] As used herein, the term "about" indicates that a quantity, size, formulation, parameter, and other variable and characteristic is not, and does not need to be, exact, but may be approximate and / or larger or smaller as required, reflecting tolerances, conversion factors, rounding and measurement errors, and other factors known to those skilled in the art. When the term "about" is used to describe a value or endpoint of a range, it should be understood that this disclosure includes the specific value or endpoint referenced. Whether or not the endpoints of a numerical value or range in this specification are stated as "about," the endpoints are intended to include both implementations: one modified with "about" and one not modified with "about." It will also be understood that each endpoint value of a range is meaningful both in relation to and unrelated to another endpoint value.

[0033] The terms “substantially,” “basically,” and their variations, as used herein, are intended to indicate that the described feature is equivalent to or approximately the same as the numerical value or description. For example, a “substantially flat” surface is intended to indicate a flat or approximately flat surface. Furthermore, “substantially” is intended to indicate that two values ​​are equal or approximately equal. In some embodiments, “substantially” may indicate that the values ​​are within approximately 10% of each other, for example, within approximately 5% of each other, or within approximately 2% of each other.

[0034] The directional terms used in this article, such as up, down, left, right, front, back, top, and bottom, are only for reference to the accompanying drawings and are not intended to indicate absolute orientation.

[0035] As used herein, the terms “the,” “an,” or “a” mean “at least one (a type)” and should not be limited to “only one” unless explicitly stated otherwise. Thus, for example, the reference to “a component” includes embodiments having two or more such components, unless otherwise explicitly stated in the text.

[0036] As used in this article, a “zigzag” road refers to a road where there is no direct line of sight through the module and the central path trajectory of the road follows more than one radius of curvature. Therefore, forming techniques based on typical machining are usually insufficient to form such roads.

[0037] See Figure 1 The flowchart in the accompanying drawings presents method 100, which includes: step 10, stacking a first metal plate and a second metal plate together, the first metal plate having opposing first and second main surfaces and one or more flow channels at least partially defined in the first main surface, the second metal plate having opposing first and second main surfaces, the plates being stacked such that their respective first main surfaces face each other and a flux layer is disposed between contact portions of the respective first main surfaces, the contact portions being defined as those portions of the respective first and second main surfaces that would contact each other without the presence of flux.

[0038] The preferred metal for sheet metal is 316L stainless steel, which exhibits excellent corrosion resistance and is readily available in various thicknesses and dimensions. Other stainless steel metals, including Hastelloy and other metals, can also be used.

[0039] The method further includes step 20, whereby the plates are heated together in a non-oxidizing atmosphere to thermally bond the contact portions of the respective first main surfaces of the first and second metal plates.

[0040] Currently, carbide powder is the preferred flux to preserve the chemical resistance of the final module. Any carbide powder (silicon carbide, boron carbide, hafnium carbide, etc.) or mixtures thereof can be used. Boron carbide is the preferred flux for reducing the sealing temperature because its bonding temperature (approximately 1210°C) is significantly lower than other carbide powders (e.g., silicon carbide requires a flux temperature of approximately 1340°C). The carbide powder or carbide powder mixture is sprayed only onto the first surface of a plate to achieve complete coverage. Some nitride powders (silicon nitride) have been found to bond well, but carbide powder fluxes offer better corrosion resistance compared to nitrides. The flux bonding process requires it to occur in a non-oxidizing or inert atmosphere (argon, vacuum, etc.). For carbide powders, the bonding process can be fully completed within 90 minutes at the peak temperature (1210°C for boron carbide).

[0041] According to an implementation of the method, the second metal plate may also have one or more flow channels that are at least partially defined in its first main surface.

[0042] According to the implementation, the heating step can be performed while the plates are pressed together, but it is also possible to succeed without external pressing. However, as the plates become relatively large, it is now preferred to fix the plates together mechanically before heating, for example by joining the plates with bolts or screws placed around their perimeter.

[0043] Figure 2 The plate 200 used in the disclosed method is shown. The plate is made of stainless steel and has channels 210 formed, for example, by machining in a first main surface 201 of the plate. The second main surface 202 of the plate 200 (… Figure 2 The position of surface 202 (which cannot be directly seen in the photograph) is opposite to the first main surface 201. Channel 210 has two input terminals 230 and one output terminal 232.

[0044] Figure 3 The (sealed) module 300 is shown after the heating step. A metal fluid connector 240 has been added.

[0045] Figure 4 This shows another completed (sealed) module 300 after the heating step. Screws are used to hold the first and second plates together at their perimeter around module 300 to prevent warping or separation during the heating process. A metal fluid connector 240 has also been added.

[0046] According to another aspect of this method, the bolts (e.g., for the fluid connector 240 at the fluid inlet and outlet) are used for the fluid inlet and outlet. The connectors can be coated with a flux material before the heating step and before screwing them into the corresponding plates. This creates a permanent and durable seal between the fluid connector 240 and the module 300. Without the thermal flux-assisted bonding of the connectors in the plates, leakage would occur under high pressure. For this purpose, the flux can be in the form of a water-based coating mixture, including silicon carbide and boron carbide powders.

[0047] For some applications, even additional corrosion resistance compared to stainless steel is required. For such applications, a carbide film (preferably silicon carbide) can be deposited on the open surfaces of the grinding channel plates before the plate stacking and heating and bonding processes. Alternatively, the channels in the finished module can be coated after heating and bonding.

[0048] As another aspect of this disclosure, a flow module is provided for use in a flow reactor or for other fluid processing, the flow module comprising: a first metal plate having opposing first and second main surfaces and one or more flow channels at least partially defined in the first main surface, and a second metal plate having opposing first and second main surfaces, the plates being bonded together by flux bonding such that their respective first main surfaces face each other.

[0049] As another aspect of this disclosure, a flow module is provided for use in a flow reactor or for other fluid processing, the flow module comprising: a first metal plate having opposing first and second main surfaces and one or more flow channels at least partially defined in the first main surface, and a second metal plate having opposing first and second main surfaces, the plates being joined together by flux-assisted interdiffusion and / or by co-melting of the facing surfaces such that their respective first main surfaces face each other.

[0050] Figure 5 This is a magnified digital photograph of the edge of an embodiment of the flow module according to aspects of this disclosure, showing the seal between the first and second plates 200a, 200b of module 300. As can be seen from the figure, there is flux-assisted interdiffusion and / or eutectic melting of the facing (“first”) surfaces of plates 200a, 200b at interface 260.

[0051] The methods and modules disclosed herein provide a low-cost approach to producing metal or stainless steel flow reactor modules. The inclusion of embedded fluid connectors facilitates user connection to the module, and the embedding process is also convenient, resulting in a robust seal between the connector and the consolidation plate. The methods also provide flow reactor modules that can be sealed or encapsulated without the need for organic materials such as gaskets or O-rings, enabling the performance of high-temperature processing or reactions, or other processes or reactions incompatible with organic materials.

[0052] While exemplary embodiments and examples have been provided for illustrative purposes, the foregoing description is not intended to limit the scope of this disclosure and the appended claims in any way. Therefore, changes and modifications can be made to the embodiments and examples described above without manifestly departing from the spirit and principles of this disclosure. All such changes and modifications are intended to be included herein, within the scope of this disclosure, and protected by the appended claims.

Claims

1. A method for forming a metal flow module, the method comprising: A first metal plate and a second metal plate are stacked together. The first metal plate has opposing first and second main surfaces and one or more flow channels at least partially defined in the first main surface. The second metal plate has opposing first and second main surfaces. The plates are stacked together such that their respective first main surfaces face each other and a flux layer is placed between the contact portions of the respective first main surfaces. The contact portions are defined as those portions of the respective first and second main surfaces that would come into contact without the presence of flux. The plates are heated together in a non-oxidizing atmosphere, thereby causing thermal bonding to occur at the contact portions of the corresponding first main surfaces of the first and second metal plates. The flux includes carbide or nitride powders.

2. The method as described in claim 1, wherein, The non-oxidizing atmosphere is an inert atmosphere.

3. The method as described in claim 1 or 2, wherein, The second metal plate has one or more flow channels that are at least partially defined in its first main surface.

4. The method as described in claim 1 or 2, wherein, Fluxes include boron carbide powder.

5. The method as described in claim 1 or 2, wherein, The boards are heated while being pressed together.

6. The method of claim 1 or 2, further comprising mechanically fixing the plates together before heating them.

7. The method of claim 6, wherein, Securing plates together mechanically includes joining them together with screws or bolts around their perimeter.

8. The method of claim 6, wherein, Securing plates together mechanically includes joining them together by screws or bolts placed around their perimeter.

9. The method of claim 6, wherein, Securing plates together mechanically includes joining them by screws or bolts placed around their perimeter and at their center.

10. The method of claim 1 or 2, further comprising coating at least a portion of the first main surface of the first and second plates with a chemical-resistant coating before stacking the plates together.

11. The method of claim 10, wherein, The corresponding part is defined as the alignment, the position of the flow channel.

12. The method of claim 1 or 2, further comprising: After the plates are heated together in a non-oxidizing atmosphere to thermally bond the contact portions of the respective first main surfaces of the first and second metal plates, a chemical-resistant coating is applied to the flow channel.

13. The method of claim 1, further comprising forming the one or more flow channels at least partially defined in the first main surface of the first plate.

14. The method of claim 13, wherein, It is formed by mechanical means.

15. The method of claim 1 or 2, further comprising: Prior to the heating, flux is applied to the bolts of the fluid connector, which is configured to be in fluid communication with the one or more flow channels; The bolt of the fluid connector is screwed into one of the first and second metal plates such that flux is located between the contact portion of the bolt of the fluid connector and one of the first and second metal plates; as well as The fluid connector and the first and second metal plates are heated in a non-oxidizing atmosphere to thermally bond the contact portions.

16. A flow module manufactured by the method of claim 1, which can be used in a flow reactor or for other fluid processing, the flow module comprising: A first metal plate having opposing first and second main surfaces and one or more flow channels at least partially defined in the first main surface; The second metal plate, having opposing first and second main surfaces, is bonded together by flux adhesive such that their respective first main surfaces face each other.

17. The streaming module of claim 16, further comprising: A fluid connector, wherein the fluid connector is engaged by flux bonding at the contact portion of at least one of the first and second metal plates with a bolt of the fluid connector to provide fluid communication with one or more flow channels.

18. A flow module manufactured by the method of claim 1, which can be used in a flow reactor or for other fluid processing, the flow module comprising: A first metal plate having opposing first and second main surfaces and one or more flow channels at least partially defined in the first main surface; The second metal plate has opposing first and second main surfaces, which are made to face each other by flux-assisted interdiffusion and / or co-melting of the facing surfaces.

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