Mixing system

Abstract

The invention relates to a mixing system comprising an outer tube (2); an inner tube (3); an annular gap (1); and a first annular diaphragm (5), wherein a first fluid can flow through the inner tube (3); a second fluid can flow through the annular gap (1); the first annular diaphragm (5) closes the annular gap (1) at the end corresponding to the end of a flow of the second fluid through the annular gap (1); the first annular diaphragm (5) is mounted so as to be connected to the outer tube (2); the first annular diaphragm (5) has a plurality of openings (5a); the outer tube (2) is shorter than the inner tube (3); the outer tube (2) is equipped with a connection (4) which is fluidically connected to the annular gap (1); and a second annular diaphragm (8) closes off the annular gap (1) at the end.

Description

[0001] mish syst tem

[0002] This invention relates to a mixing system. Mixing fluids is a widespread task in industrial applications.

[0003] Process engineering. A high mixing quality is always required to mix two fluids uniformly or, in the case of chemical reaction solutions, to achieve optimal conversion.

[0004] There is a conflict of objectives between achieving the most complete possible mixing of two or more fluids and the mixing path length. Complete mixing requires a long mixing path (see, e.g., Babcock and Wilcox, "Perspectives on Ammonia Injection and Gaseous Static Mixing in SCR Retrofit Applications" (1999)). It follows that the highest possible mixing quality should be achieved over the shortest possible path. These requirements must be met, especially in very compact reactors. For example, in plant sections where catalysts are used, very high mixing quality of all reactants is required. Due to the aforementioned conflict of objectives, chemical reactors would have to be built relatively large, which naturally has a negative impact on the overall costs of constructing a process plant. Furthermore, existing plants, which originally had very compact dimensions, are often retrofitted.

[0005] EP3725395A2 describes a fluid-gas mixer comprising a housing defining a primary axis for mixing fluid and gas, a mixing nozzle circumscribing the primary axis, with at least one annular gap defined between an outer surface of the mixing nozzle and an inner surface of the housing, an outer gas path, an inner gas passage defining an inner gas path for mixing with the outer gas path, a gas line connected to the housing for introducing gas into the inner and outer gas paths, and an attached fluid line to the mixing nozzle. The fluid line may be in fluid communication with an annular channel within the mixing nozzle, the annular channel having an outlet from the mixing nozzle parallel to the primary axis, located between the inner and outer gas paths.

[0006] CN116817047A describes an air inlet flange for introducing air into a reaction chamber for exhaust gas treatment. The flange has an annular cavity along its outer circumferential surface, such that the flange has at least one through-hole. The cavity is connected to the gas supply device via this at least one through-hole, and the cavity is connected to the reaction chamber via the flange's gas flow channel. The gas flow channel is annular and is inclined in a direction close to the flange's central axis, in line with the exhaust gas flow in the reaction chamber.

[0007] US2023356259A1 describes an application device for applying at least two miscible components, comprising component feeders and component feed nozzles arranged coaxially with the component feeders for the respective at least two components, wherein an outer feed cavity is provided as a feeder of the first component to the associated component nozzle for providing the first component, and an inner feed cavity is provided as a feeder of the second component to the associated component nozzle for providing the second component, wherein the inner feed cavity is enclosed by an inner feed tube arranged in the outer feed cavity and connected at a distance to a cavity wall of the outer feed cavity, and an axially movable valve rod is arranged in the inner feed tube, which is connected to an actuator.wherein the valve stem and / or the valve stem tip therein corresponds to a valve seat which is arranged on the component nozzle of the inner feed tube and the valve stem or the valve stem tip forms a valve with the valve seat and the inner feed cavity between the inner feed tube and the valve stem, and a mixing device is arranged downstream of the component nozzles of the feed cavities.

[0008] WO2023144029A2 describes a mixing system configured to mix a process gas into a main stream, wherein the mixing system comprises: a distribution channel; an injection unit; a static mixing unit; wherein: the distribution channel has a principal longitudinal axis which determines the flow direction of the main stream during operation; the injection unit comprises a distributor and a main injection ring; the distributor is arranged within the distribution channel and is perpendicular to the principal longitudinal axis of the distribution channel, wherein the distributor is suitable for receiving the process gas via the main injection ring; the main injection ring has a circular or annular structure and is provided with a plurality of injection ports arranged to introduce the process gas into the main stream.

[0009] The aim is therefore to provide a compact mixing system that achieves excellent mixing quality over a short mixing distance.

[0010] According to the invention, this is achieved by providing a mixing system comprising the following:

[0011] - an outer pipe;

[0012] - an inner tube arranged concentrically within the outer tube;

[0013] - an annular gap formed by the outer tube and the inner tube; and

[0014] - a first ring aperture; wherein

[0015] + the inner tube is permeable to a first fluid; + the annular gap is permeable to a second fluid to be mixed with the first fluid;

[0016] + the first annular aperture closes off the annular gap at the end that corresponds to the end of a fluid flow of the second fluid through the annular gap;

[0017] + the first ring aperture is connected to the outer tube and surrounds the inner tube flush;

[0018] + the first ring aperture has several openings through which the second fluid can flow;

[0019] + the outer pipe is shorter than the inner pipe;

[0020] + a connection is arranged in the outer tube, which is in fluid communication with the annular gap and through which the second fluid can be injected; and

[0021] + a second annular aperture closes off the annular gap at the end that corresponds to the beginning of a fluid flow of the first fluid through the inner tube.

[0022] This mixing system achieves excellent mixing quality over a short mixing distance. The first fluid flows through the inner tube. The second fluid is injected into the annular gap through the connection in the outer tube. As the second fluid exits the annular gap, it is thoroughly mixed with the first fluid exiting the inner tube over a short mixing distance.

[0023] In one embodiment, the inner tube can have serrations and recesses at the end connected to the first annular orifice. This provides an additional mixing zone, further improving the mixing quality.

[0024] In one embodiment, the first annular orifice can have an outer diameter and an inner diameter, wherein the outer diameter of the first annular orifice is larger than the diameter of the outer tube. This provides additional resistance in the fluid flow, which serves to improve mixing.

[0025] In one embodiment, the openings of the first ring aperture can be round.

[0026] In another embodiment, the openings of the first ring aperture can be square.

[0027] In one embodiment, the openings of the first annular orifice can be arranged on the inside of the first annular orifice. This facilitates the exit of the second fluid and leads to better mixing.

[0028] In one embodiment, the openings of the first annular aperture can be designed as recesses on the inside of the first annular aperture. This simplifies manufacturing.

[0029] In one embodiment, the mixing system can have a first mixing zone, formed on the top surface of the first annular orifice by a flow of the first fluid flowing along the outside of the outer tube and extending, in cross-sectional view, approximately circularly from the outside inwards, and a second mixing zone, formed on the top surface of the first annular orifice by a flow of the first fluid flowing on the inside of the inner tube and extending, in cross-sectional view, approximately circularly from the inside inwards; where "top surface" in each case refers to the side facing towards the end of the fluid flow. "Top surface" therefore also means that, during use of the mixing system, the fluids exit the inner tube and annular gap on this side and mix there.

[0030] In one embodiment, a static mixer, viewed in the direction of fluid flow, can be arranged on the inner tube or on the teeth of the inner tube. This static mixer comprises at least one swirl plate, preferably 4-12 swirl plates, an inner orifice, and an outer orifice, and has a larger diameter than the annular orifice. This static mixer results in additional and therefore improved mixing.

[0031] In one embodiment, the static mixer can have an inner opening enclosed by the inner baffle. The additional flow through the inner opening provides even better mixing.

[0032] In one embodiment, at least one swirl plate can be arranged at an angle of 30°–60° with respect to the flow direction of the fluid. This results in optimal mixing.

[0033] In one embodiment, the static mixer, viewed from above, can be (i) round or (ii) rectangular. This allows for easy adaptation to the conditions in the mixing zone.

[0034] In one embodiment, the mixing system can have a third mixing zone on the top side of the static mixer, formed by a flow of the first fluid through the inner opening and exhibiting, in cross-sectional view, an approximately circular vortex from the inside out; where "top side" refers to the side facing the end of the fluid flow. Therefore, "top side" also means the side that is located at the exit of the mixing system when the fluid flow is in use. This third mixing zone results in even better mixing.

[0035] In one embodiment, the mixing system can have a fourth mixing zone above the static mixer, formed by a flow of the first fluid through the static mixer after exiting the at least one swirl plate, and exhibiting, in a top view, a vortex approximately circular around a central axis of the inner tube; where "above" denotes the side facing the end of the fluid flow. Therefore, "above" also means the side that is located at the exit of the mixing system when the fluid flow is in use. This fourth mixing zone results in even better mixing.

[0036] In one embodiment, several mixing systems can be arranged in the fluid flow of the first fluid. This leads to better mixing across the entire cross-section of the fluid flow.

[0037] In one embodiment, the multiple mixing systems can be arranged hexagonally (two-dimensional cubic close-packed). This allows for optimal utilization of the fluid flow's cross-section.

[0038] In one embodiment, the multiple mixing systems can be arranged in a square (two-dimensional primitive cubic) configuration. This allows for optimal utilization of the fluid flow's cross-sectional area.

[0039] In one embodiment, the length of the inner tube can be greater than the length of the outer tube, preferably by a length approximately equal to the difference between the outer and inner diameters of the first annular orifice; and / or the length of the outer tube can be approximately equal to the diameter of the inner tube; and / or the outer diameter of the first annular orifice can be approximately 50% larger than the diameter of the inner tube. Such dimensions allow for cost-effective mixing.

[0040] In one embodiment, the outer diameter of the first annular orifice can be approximately 40% to 100%, preferably 50%, of the diameter or diagonal of the static mixer (10); and / or the outer diameter or diagonal of the static mixer can be 1 cm to 1.5 m; and / or the diameter or diagonal of the static mixer can be approximately 3 times the diameter of the inner tube; and / or the inner opening of the static mixer, if present, can be approximately 1 / 5 of the diameter or diagonal of the static mixer; and / or the diameter of the inner orifice of the static mixer, if present, can be approximately 35% to 80%, preferably approximately 50%, of the outer diameter or diagonal of the static mixer. Such dimensions enable cost-effective mixing.

[0041] In one embodiment, the ratio of the height of the teeth to the diameter of the inner tube can be 1:2 to 1:8, preferably 1:4. Such dimensions allow for cost-effective mixing.

[0042] The following reference symbols are used in the examples and figures:

[0043] 1 annular gap

[0044] 2 outer pipe

[0045] 3 inner tube

[0046] 4 Connection into the annular gap

[0047] 5 first ring aperture with openings

[0048] 5a Openings in the first ring aperture

[0049] 6 points

[0050] 7 exceptions

[0051] 8 second ring aperture

[0052] 10 static mixers

[0053] 11 Inner opening

[0054] 12 swirl plate

[0055] 13 Inner panel of the static mixer

[0056] 14 Outer panel of the static mixer

[0057] Drawings

[0058] Fig. 1 shows an embodiment according to the invention of the

[0059] Mixing system in exploded view. Fig. 2 shows an embodiment of the mixing system according to the invention from a low angle.

[0060] Fig. 3 shows an embodiment of the mixing system according to the invention from a slanted top view.

[0061] Fig. 4 shows an embodiment of the mixing system according to the invention from below.

[0062] Fig. 5 shows the flow behavior of the first fluid flowing past the outside of the mixing system.

[0063] Fig. 6 shows the flow behavior of the first fluid flowing through the mixing system.

[0064] Fig. 7 shows a first mixing zone formed on the top of the upper annular orifice by a flow of the first fluid flowing along the outside of the outer tube (left approximately circular arrow), and a second mixing zone formed on the top of the upper annular orifice by a flow of the first fluid flowing on the inside of the inner tube (right approximately circular arrow).

[0065] Fig. 8 shows a third mixing zone on the top of the static mixer, which is formed by a flow of the first fluid through the inner opening.

[0066] Fig. 9 shows a fourth mixing zone above the static mixer, which is formed by a flow of the first fluid through the static mixer after leaving the at least one swirl plate.

[0067] Fig. 10 shows a hexagonal (two-dimensional cubic closest-in-time) arrangement of several mixing systems. Fig. 11 shows a square (two-dimensional cubic primitive) arrangement of several mixing systems.

[0068] EXAMPLES

[0069] Example 1 - Mixing system

[0070] The mixing system comprises an outer tube 2; an inner tube 3 arranged concentrically within the outer tube 2; an annular gap 1 formed by the outer tube 2 and the inner tube 3; and a first annular orifice 5; wherein the inner tube 3 is permeable to a first fluid; the annular gap 1 is permeable to a second fluid to be mixed with the first fluid; the first annular orifice 5 closes off the annular gap 1 at the end corresponding to the end of a fluid flow of the second fluid through the annular gap 1; the first annular orifice 5 is connected to the outer tube 2 and flush-encloses the inner tube 3; the first annular orifice 5 has several openings 5a permeable to the second fluid; the outer tube 2 is shorter than the inner tube 3; a connection 4 is arranged in the outer tube 2, which is in fluid communication with the annular gap 1 and through which the second fluid can be injected;and a second annular orifice 8 closes off the annular gap 1 at the end corresponding to the beginning of a fluid flow of the first fluid through the inner tube 3. The inner tube 3 has teeth 6 and recesses 7 at the end connected to the first annular orifice 5. The openings 5a of the first annular orifice 5 are round and arranged on the inside of the first annular orifice 5.

[0071] The length of the inner tube 3 is greater than the length of the outer tube 2; the length of the outer tube 2 corresponds approximately to the diameter of the inner tube 3; and the outer diameter of the first annular orifice 5 is approximately 50% larger than the diameter of the inner tube 3. The ratio of the height of the serrations 6 to the diameter of the inner tube 3 is 1:4. Two fluids are passed through this mixing system. The first fluid is passed through the inner tube 3. The second fluid is introduced into the annular gap 1 through the connection 4 in the outer tube 2.When the second fluid exits the annular gap, it mixes with the first fluid in a first mixing zone, which is formed on the top of the first annular orifice 5 by a flow of the first fluid flowing along the outside of the outer tube 2 and, viewed in cross-section, runs approximately circularly from the outside to the inside, and a second mixing zone, which is formed on the top of the first annular orifice 5 by a flow of the first fluid flowing on the inside of the inner tube 3 and, viewed in cross-section, runs approximately circularly from the inside to the outside.

[0072] "Top side" means the side where the fluid flow exits the mixing system.

[0073] Example 2 - Mixing system with a static mixer

[0074] Starting from the mixing system of Example 1, a static mixer 10 is arranged on the teeth 6 of the inner tube 3. This static mixer 10 has four swirl plates 12, an inner orifice 13, an outer orifice 14, and an inner opening 11, and has a larger diameter than the annular orifice 5. The swirl plates 12 are arranged at an angle of 45° with respect to the flow direction of the fluid.

[0075] In addition to the dimensions given in Example 1, the outer diameter of the first annular orifice 5 is 50% of the diameter of the static mixer 10; the diameter of the static mixer (10) is approximately 3 times the diameter of the inner tube 3; the inner opening 11 of the static mixer (10) is approximately 1 / 5 of the diameter of the static mixer 10; and the diameter of the inner orifice 13 of the static mixer 10 is approximately 50% of the outer diameter of the static mixer 10. Two fluids are passed through this mixing system. The first fluid is passed through the inner tube 3. The second fluid is introduced into the annular gap 1 through the connection 4 in the outer tube 2.In addition to the two mixing zones described in Example 1, the mixing system in this example has a third mixing zone on the top side of the static mixer 10, formed by a flow of the first fluid through the inner opening 11 and exhibiting, in cross-sectional view, an approximately circular vortex from the inside out; where "top side" denotes the side facing the end of the fluid flow; and a fourth mixing zone above the static mixer 10, formed by a flow of the first fluid through the static mixer 10 after exiting the at least one swirl plate 12 and exhibiting, in top view, an approximately circular vortex around a central axis of the inner tube 3; where "above" denotes the side facing the end of the fluid flow. This ensures optimal mixing of the two fluids.

[0076] Example 3 - Arrangement of multiple mixing systems

[0077] In this example, several mixing systems from Example 1 or Example 2 are arranged hexagonally (two-dimensional cubic close-packed). This allows for optimal utilization of the fluid flow's cross-section, resulting in optimal mixing across the entire cross-section.

Claims

Patent claims:

1. Mixing system, including: - an outer tube (2) ; - an inner tube (3) which is arranged concentrically in the outer tube (2); - an annular gap (1) formed by the outer tube (2) and the inner tube (3); and - a first ring aperture (5) ; characterized in that + the inner tube (3) is permeable to a first fluid; + the annular gap (1) is permeable to a second fluid to be mixed with the first fluid; + the first annular aperture (5) closes off the annular gap (1) at the end that corresponds to the end of a fluid flow of the second fluid through the annular gap (1); + the first ring aperture (5) is arranged connected to the outer tube (2) and surrounds the inner tube (3) flush; + the first ring aperture (5) has several openings (5a) through which the second fluid can flow; + the outer tube (2) is shorter than the inner tube (3) ; + a connection (4) is arranged in the outer tube (2) which is in fluid communication with the annular gap (1) and through which the second fluid can be injected; and + a second annular aperture (8) closes off the annular gap (1) at the end that corresponds to the beginning of a fluid flow of the first fluid through the inner tube (3).

2. Mixing system according to claim 1, characterized in that the inner tube (3) has teeth (6) and recesses (7) at the end which is connected to the first annular aperture (5).

3. Mixing system according to claim 1 or 2, characterized in that the first annular aperture (5) has an outer diameter and an inner diameter, wherein the outer diameter of the first annular aperture (5) is larger than the diameter of the outer tube (2) .

4. Mixing system according to one of the preceding claims, characterized in that the openings (5a) of the first ring aperture (5) are round.

5. Mixing system according to one of claims 1 to 3, characterized in that the openings (5a) of the first ring aperture (5) are rectangular.

6. Mixing system according to one of the preceding claims, characterized in that the openings (5a) of the first annular aperture (5) are arranged on the inside of the first annular aperture (5).

7. Mixing system according to one of the preceding claims, characterized in that the openings (5a) of the first annular aperture (5) are designed as recesses on the inside of the first annular aperture (5).

8. Mixing system according to one of the preceding claims, characterized in that the mixing system has a first mixing zone formed on the top of the first annular orifice (5) by a flow of the first fluid flowing along the outside of the outer tube (2) and, viewed in cross-sectional view, extends approximately circularly from the outside to the inside, and a second mixing zone formed on the top of the first annular orifice (5) by a flow of the first fluid flowing on the inside of the inner tube (3) and, viewed in cross-sectional view, extends approximately circularly from the inside to the outside; where "top" refers to the side that points towards the end of the fluid flow.

9. Mixing system according to one of the preceding claims, characterized in that a static mixer (10) is arranged on the inner tube (3) or on the teeth (6) of the inner tube (3) in the direction of fluid flow, which static mixer (10) has at least one swirl plate (12), preferably 4-12 swirl plates (12), an inner orifice (13) and an outer orifice (14) and has a larger diameter than the annular orifice (5).

10. Mixing system according to claim 9, characterized in that the static mixer (10) has an inner opening (11) which is enclosed by the inner baffle (13).

11. Mixing system according to one of claims 9 to 10, characterized in that the at least one swirl plate (12) is arranged at an angle of 30°-60° with respect to the flow direction of the fluid.

12. Mixing system according to one of claims 9 to 11, characterized in that the static mixer (10) is (i) round or (ii) square when viewed from above.

13. Mixing system according to one of claims 10 to 12, characterized in that the mixing system has a third mixing zone on the top side of the static mixer (10), which is formed by a flow of the first fluid through the inner opening (11) and, viewed in cross-sectional view, exhibits a vortex approximately circular from the inside out; wherein “top side” denotes the side that points towards the end of the fluid flow.

14. Mixing system according to one of claims 9 to 13, characterized in that the mixing system has a fourth mixing zone above the static mixer (10), which is formed by a flow of the first fluid through the static mixer (10) after leaving the at least one swirl plate (12) and, viewed from above, has a vortex approximately circular around a central axis of the inner tube (3); wherein “above” denotes the side that points towards the end of the fluid flow.

15. Mixing system according to one of the preceding claims, characterized in that several mixing systems are arranged in the fluid flow of the first fluid.

16. Mixing system according to claim 15, characterized in that the multiple mixing systems are arranged hexagonally (two-dimensional cubic close space).

17. Mixing system according to claim 15, characterized in that the multiple mixing systems are arranged in a square (two-dimensional cubic primitive) configuration.

18. Mixing system according to one of the preceding claims, characterized in that + the length of the inner tube (3) is greater than the length of the outer tube (2), preferably by a length approximately equal to the difference between the outer diameter and the inner diameter of the first annular aperture (5); and / or + the length of the outer tube (2) corresponds approximately to the diameter of the inner tube (3); and / or + the outer diameter of the first ring aperture (5) is approximately 50% larger than the diameter of the inner tube (3) .

19. Mixing system according to one of claims 9-18, characterized in that + the outer diameter of the first annular aperture (5) is approximately 40% to 100%, preferably 50%, of the diameter or diagonal of the static mixer (10); and / or + the outer diameter or diagonal of the static mixer (10) is 1 cm to 1.5 m; and / or + the diameter or diagonal of the static mixer (10) is approximately 3 times the diameter of the inner tube (3) ; and / or + the inner opening (11) of the static mixer (10), if present, is approximately 1 / 5 of the diameter or diagonal of the static mixer (10); and / or + the diameter of the inner aperture (13) of the static mixer (10), if present, is approximately 35% to 80%, preferably approximately 50%, of the outer diameter or diagonal of the static mixer (10).

20. Mixing system according to one of claims 2-19, characterized in that + the ratio of the height of the teeth (6) to the diameter of the inner tube (3) is 1:2 to 1:8, preferably 1:4.

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