Double-layer composite micro-reaction channel plate with stereoscopic ladder channel, micro-channel reactor

Abstract

The present application relates to the field of micro-reactor, and discloses a double-layer composite micro-reaction channel plate with three-dimensional stepped channels and a micro-channel reactor.The double-layer composite micro-reaction channel plate comprises an upper channel plate and a lower channel plate which are superimposed;the top surface of the upper channel plate is provided with heat exchange channels A, and the bottom surface is provided with a first fluid inlet;the first fluid pre-heat exchange channel;the second fluid inlet;the second fluid pre-heat exchange channel;the mixing channel;and the mixed fluid outlet.A plurality of stepped cavities A are staggered along the flow direction at the bottom of the mixing channel.The bottom surface of the lower channel plate is provided with heat exchange channels B, and the top surface is provided with stepped cavities B which correspond to the positions and sizes of the stepped cavities A one by one.The double-layer composite micro-reaction channel plate of the present application is provided with special three-dimensional stepped channels, and the mixed fluid will produce fluctuation when passing through the structure, which can greatly enhance the disturbance of the fluid under the premise of not increasing the fluid resistance, so that the advection becomes turbulent flow, and the mixing effect is significantly enhanced.

Description

Technical Field

[0001] This invention relates to the field of microreactors, and more particularly to a double-layer composite microreactor plate with three-dimensional stepped channels and a microchannel reactor. Background Technology

[0002] A microchannel reactor is a three-dimensional component fabricated using microfabrication techniques on a solid substrate, within which chemical reactions can take place. Microchannel reactors are characterized by their small channel size and diverse channel configurations, allowing fluid to flow and the desired reaction to occur within the channels. Due to their large specific surface area, microchannel reactors exhibit superior heat and mass transfer performance compared to traditional reactors such as reaction vessels.

[0003] In microchannel reactors, fluids are generally in a laminar flow state due to the low Reynolds number at the microscale. This means that when two or more fluids move in parallel directions, they can only mix through molecular diffusion. This mixing method is inefficient and requires a long time and distance to achieve uniform mixing. In practical project development, to improve mixing efficiency, passive or active micromixers can be used to enhance convection or disturbance between fluids. One type is the passive micromixer, which increases the contact area or generates secondary flow by changing the geometry or surface characteristics of the internal channels. For example, various structural units are designed in the channels, including but not limited to partitions, folds, serpentine shapes, and herringbone structures, to create local velocity differences in the fluids, thereby disrupting the laminar flow state and forming various forms such as eddies and turbulence, thus improving mixing efficiency. The other type is the active micromixer, which excites bubbles or droplets to move or oscillate by applying external force fields, such as electric fields, magnetic fields, and sound waves. For example, piezoelectric ceramic sensors that can generate ultrasonic waves to cause droplet oscillations can be integrated into the microreactor.

[0004] However, both passive and active micromixers typically lead to increased pressure drop in the system. According to the continuity equation and Bernoulli's equation, velocity and pressure change as the channel cross-section changes. Therefore, in channels with complex geometries or surface features, the frequent changes in cross-sectional size or orientation cause significant fluctuations in velocity and pressure, generally exhibiting a decreasing trend along the flow path. This results in the entire system requiring higher inlet pressure to maintain the desired mass flow rate. Therefore, the design of microchannel mixing structures must consider the trade-off between pressure drop and heat transfer efficiency, and select the optimal solution based on the specific application.

[0005] In existing technologies, when designing the unit structure of microchannel reactors, such as in patent CN 110652949A, the reaction chamber is designed in an octagonal fish shape to improve mixing efficiency. This design achieves high-efficiency mixing by continuously spraying and dividing the fluid. However, as the reaction chambers are stacked, this structure significantly increases the pressure drop of the system. When the reaction time reaches the minute level, a longer reaction channel is often required.

[0006] In summary, current requirements for microchannel reactors include achieving continuous and efficient mixing while ensuring low pressure drop operation of the system. Summary of the Invention

[0007] To address the aforementioned technical problems, this invention provides a double-layer composite microreactor channel plate and a microchannel reactor containing three-dimensional stepped channels. The double-layer composite microreactor channel plate of this invention features a specially structured three-dimensional stepped channel. When the mixed fluid passes through this structure, it undergoes undulating motion, significantly enhancing the disturbance to the fluid without increasing fluid resistance, transforming advection into turbulence, and significantly improving the mixing effect.

[0008] The specific technical solution of this invention is as follows:

[0009] In a first aspect, the present invention provides a double-layer composite microreaction channel plate containing a three-dimensional stepped channel, comprising an upper channel plate and a lower channel plate stacked on top of each other.

[0010] The top surface of the upper channel plate is provided with a heat exchange channel A, and the bottom surface is provided with: a first fluid inlet; a first fluid pre-heat exchange channel connected to the first fluid inlet; a second fluid inlet; a second fluid pre-heat exchange channel connected to the second fluid inlet; a mixing channel where the ends of the first and second fluid pre-heat exchange channels converge and connect at the same point, and the bottom of the mixing channel has several stepped cavities A arranged alternately along the flow direction; and a mixed fluid outlet connected to the end of the mixing channel.

[0011] The bottom surface of the lower channel plate is provided with a heat exchange channel B, and the top surface is provided with several stepped concave cavities B that correspond one by one in position and size to the stepped concave cavities A; the mixed flow channel, stepped concave cavities A and stepped concave cavities B are stacked on top of each other to form a three-dimensional stepped channel.

[0012] The working principle of the double-layer composite micro-reaction channel plate with a three-dimensional stepped channel of this invention is as follows: the mixing channel and stepped cavity A / B in the upper and lower channel plates are stacked to form a closed three-dimensional stepped channel. After entering the upper channel plate, the two fluids first pass through a preheating / cooling channel to reach the reaction temperature before mixing. When the two fluids reach the end of the preheating channel, they merge and immediately enter the mixing channel (three-dimensional stepped channel). The three-dimensional stepped channel of this invention has a special three-dimensional stepped structure. When the fluid passes through this structure, it will generate undulating motion, which can significantly enhance the disturbance of the fluid without increasing the fluid resistance, turning the advection into turbulence and enhancing the mixing effect.

[0013] Compared to conventional designs that use turbulence blocks on the same horizontal plane of the flow channel to induce turbulence, the double-layer stepped structure of this invention offers the following advantages: ① The double-layer stepped structure can more effectively alter the flow direction and velocity distribution of the fluid, resulting in a larger contact area between the fluid and the channel wall, stronger relative motion, and significantly improved heat and mass transfer efficiency. ② The stepped structure design reduces the obstruction of the channel cross-section by conventional turbulence blocks. When designed as a double-layer stepped structure, it can achieve low pressure loss and low energy consumption at higher flux levels. ③ The double-layer stepped structure can utilize the centrifugal and inertial forces generated by the multi-directional movement of the fluid to form multiple local vortices and secondary flows at the step junctions, further enhancing the degree of turbulence and turbulence intensity. In summary, compared to conventional turbulence block structures, the double-layer stepped structure, through the diversion of fluid flow to the stepped cavities, not only effectively reduces pressure drop but also greatly improves the mass and heat transfer efficiency of the fluid in the channel.

[0014] As a preferred embodiment ①, the stepped concave cavities A are arranged in a single row in an alternating pattern along the flow direction. Two adjacent stepped concave cavities A are connected to different sidewalls of the mixing channel. The angle between the length direction of a single stepped concave cavity A and the sidewall of the mixing channel it is connected to is 40-50°. The arrangement of the stepped concave cavities B coincides with the arrangement of the stepped concave cavities A after rotating 180° along the centerline of the mixing channel from a top-down perspective.

[0015] Reducing the angle between the length of a single stepped cavity and its connected sidewall can decrease pressure loss and improve fluid mixing efficiency. The angle between the length of a single stepped cavity and its connected sidewall affects the micro-mixing effect of the fluid in the microchannel; selecting an angle of 40° to 50° can balance the mixing performance and pressure drop of the fluid within the stepped cavity.

[0016] Preferably, the depth of the mixing channel is 0.4-1.2 mm; the depth of the stepped cavity A and stepped cavity B relative to the mixing channel is 0.2-0.6 mm. More preferably, the depth of the mixing channel is 0.6-0.8 mm; the depth of the stepped cavity A and stepped cavity B relative to the mixing channel is 0.3-0.4 mm.

[0017] Depending on the reaction conditions and processes, microchannel reactors with different flux scales are often designed, specifically in terms of the depth and width ratio of the channels. With a fixed width, a smaller channel depth results in a lower Reynolds number and a more laminar flow. While greater depth increases reaction flux, excessive depth can also increase fluid residence time distribution, necessitating structural design to enhance mass transfer capacity. Therefore, the channel design of microchannel reactors requires theoretical analysis and numerical simulation, comprehensively considering factors such as fluid flow field, mass and heat transfer, and chemical reaction characteristics, followed by optimization and improvement through model verification and experimental testing.

[0018] In scheme ①, the ratio of the depth of the stepped cavity to the depth of the mixing channel is a crucial parameter. If the ratio is too large, the turbulence of the fluid entering the stepped cavity will actually weaken, and the RTD (residence time distribution) will increase; if the ratio is too small, the turbulence will be insufficient, failing to achieve the desired effect. Designing a reasonable ratio range maximizes the use of the inertial and centrifugal forces generated by the undulating motion, forming local vortices and secondary flows at the stepped interface, further enhancing the degree of turbulence and the intensity of disturbance.

[0019] As a preferred embodiment ②, the stepped concave cavity A is divided into shallow stepped concave cavity A and deep stepped concave cavity A, and is arranged in a double row staggered arrangement along the flow direction, including a left single row and a right single row that are parallel to each other; the stepped concave cavities A in the left single row and the right single row are respectively connected to the left and right side walls of the mixing channel; all the stepped concave cavities A in the parallel double row composed of the two single rows are arranged along the flow direction with “shallow stepped concave cavity A in the left single row → deep stepped concave cavity A in the right single row → shallow stepped concave cavity A in the right single row → deep stepped concave cavity A in the left single row” as the smallest repeating unit, and the ends of the two corresponding stepped concave cavities A in the left single row and the right single row are connected; the angle between the length direction of a single stepped concave cavity A and the side wall of the mixing channel it is connected to is 40-50°. The stepped cavity B is divided into a shallow stepped cavity B and a deep stepped cavity B. The arrangement of the shallow stepped cavity B and the deep stepped cavity B is obtained by rotating the arrangement of the shallow stepped cavity A and the deep stepped cavity A by 180° along the center line of the mixing channel from a top-down perspective.

[0020] Compared to Scheme 1, Scheme 2 has the disadvantage of a more complex structural design, increasing the difficulty of channel fabrication. However, its advantages are also significant: it is suitable for larger throughputs and has stronger disturbance capabilities. Compared to the double-layered single-step design in Scheme 1, Scheme 2 features a double-layered double-stepped design, with alternating vertical distribution. As the fluid flows forward, a portion flows into step one and then splits into two flows. One flow is disturbed upwards into the main channel and enters step two on the opposite side, while the other flow is downwards into step two, increasing the inertial force of the lateral flow and the turbulent force of the longitudinal flow. Simultaneously, another portion of the fluid in the main channel directly enters step two, where it is disturbed and mixed with the previous portion. This two-stepped structure allows the fluid to undulate between different platform levels, thereby changing the direction, velocity, pressure, and turbulence level of the fluid. Compared to a single-stepped structure, the two-stepped structure has the following advantages: ① It can increase the mixing efficiency of the fluid and improve mass transfer performance. ② It increases the specific surface area of ​​the reactor and improves heat transfer performance. ③ The distribution and direction of the fluid can be adjusted to control multiphase flow or non-uniform flow. In addition, according to fluid mechanics theory, the two stepped structures can affect fluid motion through the following mechanisms: (1) Local acceleration effect is generated at the gap between the steps, resulting in a pressure difference between the upper and lower platforms. (2) Shear effect is generated at the edge of the steps, resulting in a velocity difference between the viscous layer near the wall and the inviscid layer away from the wall. (3) Vortex effect is generated behind the steps, resulting in a cyclic exchange between the low-pressure region inside the vortex core and the high-pressure region outside the vortex.

[0021] Preferably, the depth of the mixing channel is 0.4-1.2 mm; the depth of the shallow stepped cavity A and shallow stepped cavity B relative to the mixing channel is 0.1-0.3 mm; and the depth of the deep stepped cavity A and deep stepped cavity B relative to the mixing channel is 0.2-0.6 mm. More preferably, the depth of the mixing channel is 0.5-0.6 mm; the depth of the shallow stepped cavity A and shallow stepped cavity B relative to the mixing channel is 0.15-0.2 mm; and the depth of the deep stepped cavity A and deep stepped cavity B relative to the mixing channel is 0.25-0.3 mm.

[0022] The double-layered, two-step structure in Scheme ② allows the fluid to experience more shearing and diffusion as it passes through the corresponding upper and lower steps, thereby improving fluid turbulence and mixing efficiency. The depth design of the two-step structure needs to consider factors such as the fluid's Reynolds number and pressure drop loss, and is generally optimized using numerical simulations or experimental tests. This invention utilizes the Navier-Stokes equations and the continuity equation to describe the fluid's motion within the two-step structure and solves for parameters such as the velocity field, pressure field, and temperature field.

[0023] Preferably, the width of the mixing channel is 0.5-3 mm, and more preferably 1-2 mm.

[0024] Preferably, the flow channel width at the confluence of the first fluid preheating channel, the second fluid preheating channel, and the mixing channel is narrowed.

[0025] Preferably, the angle between the first fluid preheating channel and the second fluid preheating channel is 55-65°, and the angle between the mixing channel and the first fluid preheating channel and the second fluid preheating channel is equal.

[0026] In this invention, the confluence of the first and second fluid preheating channels and the mixing channel is Y-shaped. The technical advantage is that ordinary collision or Y-shaped inlet mixing efficiency is insufficient, while using a narrow-diameter mode can lead to excessive pressure drop due to narrow-diameter collision. This invention combines narrow-diameter and Y-shaped inlets, which not only increases the flow velocity and enhances the mixing effect, but also controls excessive pressure drop.

[0027] Preferably, the first fluid preheating channel, the second fluid preheating channel, and the mixing channel are in a tortuous and meandering shape along the flow direction.

[0028] Preferably, the heat exchange channels A and B are tortuous and meandering, and the upper and lower channel plates are provided with a through heat exchange liquid inlet and a heat exchange liquid outlet. Several guide strips are distributed along the flow direction at the bottom of the heat exchange channels A and B. The two ends of the heat exchange channels A and B are respectively connected to the heat exchange liquid inlet and the heat exchange liquid outlet.

[0029] Secondly, the present invention provides a microchannel reactor, comprising an upper cover plate, an upper channel plate, a lower channel plate, and a lower cover plate stacked sequentially from top to bottom.

[0030] Preferably, the upper cover plate is provided with a first fluid inlet, a second fluid inlet, a mixed fluid outlet, a heat exchange fluid inlet, and a heat exchange fluid outlet.

[0031] Compared with the prior art, the beneficial effects of the present invention are as follows: The double-layer composite micro-reaction channel plate of the present invention is provided with a three-dimensional stepped channel with a special structure. When the mixed fluid passes through this structure, it will generate undulating motion. Without increasing the fluid resistance, it can greatly enhance the disturbance of the fluid, turn the advection into turbulence, and significantly enhance the mixing effect. Attached Figure Description

[0032] Figure 1 This is a split schematic diagram of the microchannel reactor in Embodiment 1 of the present invention from a frontal view.

[0033] Figure 2 This is a split schematic diagram of the bottom surface of the microchannel reactor in Embodiment 1 of the present invention;

[0034] Figure 3This is a side sectional view of a double-layer composite microreaction channel plate according to Embodiment 1 of the present invention;

[0035] Figure 4 This is a schematic diagram of the bottom surface of the upper channel plate in Embodiment 1 of the present invention;

[0036] Figure 5 This is a partial schematic diagram of the mixing channel in the upper channel plate of Embodiment 1 of the present invention;

[0037] Figure 6 This is a schematic diagram of the front (left) and bottom (right) surfaces of the lower channel plate according to Embodiment 1 of the present invention;

[0038] Figure 7 This is a split schematic diagram of the microchannel reactor from the front view of Embodiment 2 of the present invention;

[0039] Figure 8 This is a split schematic diagram showing the bottom surface of the microchannel reactor in Embodiment 2 of the present invention.

[0040] Figure 9 This is a side cross-sectional view of the mixing channel in the double-layer composite microreaction channel plate of Embodiment 2 of the present invention;

[0041] Figure 10 for Figure 9 Top view (perspective view);

[0042] Figure 11 This is a schematic diagram of the bottom surface of the upper channel plate in Embodiment 2 of the present invention;

[0043] Figure 12 This is a partial schematic diagram of the mixing channel in the upper channel plate of Embodiment 2 of the present invention;

[0044] Figure 13 This is a schematic diagram of the front of the lower channel plate in Embodiment 2 of the present invention;

[0045] Figure 14 The figure shows the simulation test results of the microchannel reactor in Embodiment 1 of the present invention;

[0046] Figure 15 This is a simulation diagram of the velocity field distribution of two fluid streams in the microchannel reactor of Embodiment 1 of the present invention;

[0047] Figure 16 The figure shows the simulation test results of the microchannel reactor in Embodiment 2 of the present invention;

[0048] Figure 17 This is a simulation diagram of the velocity field distribution of two fluid streams in the microchannel reactor of Embodiment 2 of the present invention.

[0049] The attached diagram is labeled as follows: upper cover plate 1, upper channel plate 2, lower channel plate 3, lower cover plate 4, heat exchange channel A 21, first fluid inlet 22, first fluid pre-heat exchange channel 23, second fluid inlet 24, second fluid pre-heat exchange channel 25, mixing channel 26, stepped cavity A 27, mixed fluid outlet 28, shallow stepped cavity A 271, deep stepped cavity A 272, left single row 273, right single row 274, heat exchange channel B 31, stepped cavity B 32, heat exchange liquid inlet 33, heat exchange liquid outlet 34, guide bar 35, shallow stepped cavity B 321, deep stepped cavity B 322. Detailed Implementation

[0050] The present invention will be further described below with reference to embodiments.

[0051] General Implementation Examples

[0052] A double-layer composite microreaction channel plate containing three-dimensional stepped channels, such as Figure 1-13 As shown, it includes an upper channel plate 2 and a lower channel plate 3 that are stacked vertically. Wherein:

[0053] like Figure 1 and Figure 7 The top surface of the upper channel plate is provided with a tortuous heat exchange channel A21, such as... Figure 2 , Figure 4-5 , Figure 8-12 The bottom surface is provided with:

[0054] First fluid inlet 22;

[0055] A tortuous first fluid preheat exchange channel 23 connected to the first fluid inlet; a second fluid inlet 24;

[0056] A tortuous second fluid preheating channel 25 connected to the second fluid inlet;

[0057] A mixing channel 26, which is connected to the ends of the first and second fluid preheating channels at the same point, has several stepped recesses A 27 arranged alternately along the flow direction at the bottom of the mixing channel; the flow channel width at the confluence of the first and second fluid preheating channels and the mixing channel is narrowed; the included angle between the first and second fluid preheating channels is 55-65°; and the included angle between the mixing channel and the first and second fluid preheating channels is equal.

[0058] Mixed fluid outlet 28 connected to the end of the mixing channel.

[0059] like Figure 6 As shown on the right, the bottom surface of the lower channel plate is provided with a heat exchange channel B 31, as follows: Figure 6 (left) and Figure 13As shown, the top surface is provided with several stepped concave cavities B 32 that correspond one by one in position and size to the stepped concave cavity A; the mixing channel, stepped concave cavity A and stepped concave cavity B are stacked on top of each other to form a three-dimensional stepped channel.

[0060] The upper and lower channel plates are also provided with a through heat exchange liquid inlet 33 and a heat exchange liquid outlet 34. Several guide strips 35 are distributed along the flow direction at the bottom of heat exchange channel A and heat exchange channel B. The two ends of heat exchange channel A and heat exchange channel B are respectively connected to the heat exchange liquid inlet and heat exchange liquid outlet.

[0061] Preferably, the width of the mixing channel is 0.5-3 mm, and more preferably 1-2 mm.

[0062] As one of the preferred options, such as Figure 4-5 As shown, the stepped cavities A are arranged in a single row in an alternating pattern along the flow direction. Two adjacent stepped cavities A are connected to different sidewalls of the mixing channel. The angle between the length direction of a single stepped cavity A and the sidewall of the mixing channel it is connected to is 40-50°. Figure 6 As shown on the left, the arrangement of the stepped cavities B coincides with the arrangement of the stepped cavities A after rotating 180° along the centerline of the mixing channel from a top-down perspective. Preferably, the depth of the mixing channel is 0.4-1.2 mm; the depth of the stepped cavities A and B relative to the mixing channel is 0.2-0.6 mm. More preferably, the depth of the mixing channel is 0.6-0.7 mm; the depth of the stepped cavities A and B relative to the mixing channel is 0.3-0.4 mm.

[0063] As a second preferred option, such as Figure 11-12 As shown, the stepped cavity A is divided into shallow stepped cavity A 271 and deep stepped cavity A 272, and is arranged in a double-row staggered pattern along the flow direction, including a left single row 273 and a right single row 274 that are parallel to each other; the stepped cavity A in the left and right single rows are connected to the left and right side walls of the mixing channel, respectively. All the stepped cavity A in the parallel double rows formed by the two single rows are arranged along the flow direction with "shallow stepped cavity A in the left single row → deep stepped cavity A in the right single row → shallow stepped cavity A in the right single row → deep stepped cavity A in the left single row" as the smallest repeating unit, and the ends of the two corresponding stepped cavity A in the left and right single rows are connected. The angle between the length direction of a single stepped cavity A and the side wall of the mixing channel it is connected to is 40-50°. Figure 13As shown, the stepped cavity B is divided into a shallow stepped cavity B 321 and a deep stepped cavity B 322. The arrangement of the shallow and deep stepped cavities B, viewed from a top-down angle, is obtained by rotating the arrangement of the shallow and deep stepped cavities A by 180° along the centerline of the mixing channel. The depth of the mixing channel is 0.4-1.2 mm; the depth of the shallow stepped cavities A and B relative to the mixing channel is 0.1-0.3 mm; and the depth of the deep stepped cavities A and B relative to the mixing channel is 0.2-0.6 mm. More preferably, the depth of the mixing channel is 0.5-0.6 mm; the depth of the shallow stepped cavities A and B relative to the mixing channel is 0.15-0.2 mm; and the depth of the deep stepped cavities A and B relative to the mixing channel is 0.25-0.3 mm.

[0064] A microchannel reactor includes an upper cover plate 1, an upper channel plate 2, a lower channel plate 3, and a lower cover plate 4 stacked sequentially from top to bottom. The upper cover plate is provided with a first fluid inlet 22, a second fluid inlet 24, a mixed fluid outlet 28, a heat exchange liquid inlet 33, and a heat exchange liquid outlet 34.

[0065] Example 1 (stepped concave cavities arranged in a single row in an alternating pattern)

[0066] A microchannel reactor, such as Figure 1 and 2 As shown, the system includes an upper cover plate 1, an upper channel plate 2, a lower channel plate 3, and a lower cover plate 4 stacked from top to bottom. The upper cover plate is provided with a first fluid inlet 22, a second fluid inlet 24, a mixed fluid outlet 28, a heat exchange fluid inlet 33, and a heat exchange fluid outlet 34.

[0067] like Figure 1 As shown, the top surface of the upper channel plate is provided with a tortuous heat exchange channel A21 (a total of 5 180° U-shaped bends), such as... Figure 4 As shown, the bottom surface has:

[0068] First fluid inlet 22;

[0069] A tortuous first fluid preheating channel 23 (with four 180-degree U-shaped bends and two right-angle bends in sequence, with a total length of 0.8m) connected to the first fluid inlet; and a second fluid inlet 24;

[0070] A meandering second fluid preheating channel 25 connected to the second fluid inlet (with four 180-degree U-shaped bends and one 135-degree bend in sequence, with a total length of 0.8m).

[0071] A meandering mixed-flow channel 26 (with six 180-degree U-shaped bends in sequence, totaling 1m in length) connects to the ends of the first and second fluid preheating channels at the same point. As shown in Figure 5, the bottom of the mixed-flow channel has a single row of staggered parallelogram-shaped stepped concave cavities A 27 along the flow direction. Two adjacent stepped concave cavities A are connected to different sidewalls of the mixed-flow channel (the center point distance between two adjacent stepped concave cavities A (one on the left and one on the right) in the flow direction is 3.8mm, the length of a single stepped concave cavity A in the flow direction is 2mm, and the distance between the free end of the stepped concave cavity A and the sidewall of the flow channel is 2mm). The angle between the length direction of a single stepped concave cavity A and the sidewall of the mixed-flow channel it connects to is 45°. The flow channel width at the confluence of the first and second fluid preheating channels and the mixed-flow channel is narrowed. The angle between the first and second fluid preheating channels is 60°, and the angle between the mixed-flow channel and the first and second fluid preheating channels is equal.

[0072] Mixed fluid outlet 28 connected to the end of the mixing channel.

[0073] The bottom surface of the lower channel plate is provided with a heat exchange channel B 31 (the shape and size are the same as the heat exchange channel A), and the top surface is provided with several stepped recesses B 32 that correspond one-to-one with the position and size of the stepped recesses A; the mixing channel, stepped recesses A and stepped recesses B are stacked one on one to form a three-dimensional stepped channel. Figure 3 ).like Figure 6 As shown on the left, the arrangement of the stepped concave cavities B coincides with the arrangement of the stepped concave cavities A after rotating 180° along the centerline of the mixing channel from a top-down perspective.

[0074] The upper and lower channel plates are also provided with a through heat exchange liquid inlet 33 and a heat exchange liquid outlet 34. Several guide strips 35 are distributed along the flow direction at the bottom of heat exchange channel A and heat exchange channel B. The two ends of heat exchange channel A and heat exchange channel B are respectively connected to the heat exchange liquid inlet and heat exchange liquid outlet.

[0075] In terms of dimensions, the width of the mixing channel is 2 mm and the depth is 0.7 mm; the depth of the stepped cavity A and stepped cavity B relative to the mixing channel is 0.35 mm.

[0076] The working principle of the microchannel reactor in this embodiment is as follows: After the two fluids enter the upper channel plate, they first pass through a preheating / cooling channel to reach the reaction temperature before mixing. When the two fluids reach the end of the preheating channel, they merge and immediately enter the mixing channel. At the same time, the heat exchange liquid circulates in heat exchange channels A and B and exchanges heat with the fluid. Therefore, the fluid is fully mixed and reacts in the mixing channel.

[0077] Simulation Test: Using water as the fluid medium model, the microchannel reactor of Example 1 was used for simulation testing. The concentration standard deviation was used as the evaluation of the fluid mixing effect. Figure 14 As shown, the mixing efficiency can reach 99.99% and 100% at flow rates of 0.1 mm / s and 1 mm / s, respectively; Figure 15 The figure shows a simulation of the velocity field distribution of the two fluid streams in the channel.

[0078] Example 2 (stepped concave cavities arranged in two staggered rows)

[0079] The difference between Example 2 and Example 1 is as follows:

[0080] like Figure 7-8 , Figure 11-12 As shown, in the upper channel plate, the stepped cavity A is divided into shallow stepped cavity A 271 and deep stepped cavity A 272, and is arranged in a double row staggered along the flow direction, including a left single row 273 and a right single row 274 that are parallel to each other; the stepped cavity A in the left single row and the right single row are connected to the left and right side walls of the mixing channel respectively (all stepped cavities are parallelogram-shaped and have the same size). All stepped cavities A in the parallel double row composed of two single rows are arranged along the flow direction with "shallow stepped cavity A in the left single row → deep stepped cavity A in the right single row → shallow stepped cavity A in the right single row → deep stepped cavity A in the left single row" as the smallest repeating unit, and the ends of the two corresponding stepped cavities A in the left single row and the right single row are connected. The angle between the length direction of a single stepped cavity A and the side wall of the mixing channel it is connected to is 45°.

[0081] like Figure 9-10 and Figure 13 As shown, in the lower channel plate, the stepped cavity B is divided into a shallow stepped cavity B 321 and a deep stepped cavity B 322. The arrangement of the shallow stepped cavity B and the deep stepped cavity B is obtained by rotating the arrangement of the shallow stepped cavity A and the deep stepped cavity A 180° along the center line of the mixing channel from the top view.

[0082] In terms of dimensions, the mixing channel has a width of 2 mm and a depth of 0.552 mm; the shallow stepped cavity A and shallow stepped cavity B have a depth of 0.17 mm relative to the mixing channel; the deep stepped cavity A and deep stepped cavity B have a depth of 0.27 mm relative to the mixing channel. The center-to-center distance between two adjacent stepped cavities in the left single row in the flow direction is 2.8 mm, and the center-to-center distance between two interconnected left and right stepped cavities in the flow direction is 1 mm.

[0083] Simulation Test: Using water as the fluid medium model, simulation tests were conducted using the microchannel reactor from Example 2. Figure 16 As shown, a mixing efficiency of 99.99% can be achieved at a flow rate of 0.1 mm / s; Figure 17The figure shows a simulation of the velocity field distribution of the two fluid streams in the channel.

[0084] Unless otherwise specified, the raw materials and equipment used in this invention are all commonly used in the field; unless otherwise specified, the methods used in this invention are all conventional methods in the field.

[0085] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Any simple modifications, alterations, and equivalent transformations made to the above embodiments based on the technical essence of the present invention shall still fall within the protection scope of the present invention.

Claims

1. A double-layer composite microreaction channel plate containing three-dimensional stepped channels, characterized in that: The upper channel plate and the lower channel plate are superimposed on each other; The upper channel plate is provided with a heat exchange channel A on the top surface and a heat exchange channel B on the bottom surface; A first fluid inlet; A first fluid pre-heat exchange channel in communication with the first fluid inlet; A second fluid inlet; A second fluid pre-heat exchange channel in communication with the second fluid inlet; A mixed flow channel in communication with the first and second fluid pre-heat exchange channels at the same end of the mixed flow channel, and a plurality of stepped cavities A are staggered along the flow direction at the bottom of the mixed flow channel; A mixed fluid outlet in communication with the end of the mixed flow channel; The lower channel plate is provided with a heat exchange channel B on the bottom surface and a plurality of stepped cavities B on the top surface corresponding to the positions and sizes of the stepped cavities A; the mixed flow channel, the stepped cavities A and the stepped cavities B are superimposed on each other to form a three-dimensional stepped channel; The stepped cavities A are divided into shallow stepped cavities A and deep stepped cavities A, and are arranged in double staggered rows along the flow direction, including parallel left single row and right single row; all the stepped cavities A in the parallel double row formed by the two single rows are arranged along the flow direction as the smallest repeating unit in the form of "left single row shallow stepped cavity A→right single row deep stepped cavity A→right single row shallow stepped cavity A→left single row deep stepped cavity A".

2. The double-layered composite micro-reaction channel plate with stereoladder channels according to claim 1, characterized in that: The stepped cavities A in the left single row and the right single row are connected to the left and right side walls of the mixed flow channel respectively, and the end portions of the corresponding two stepped cavities A in the left single row and the right single row are connected, and the angle between the length direction of a single stepped cavity A and the side wall of the mixed flow channel connected thereto is 40-50°; The stepped cavities B are divided into shallow stepped cavities B and deep stepped cavities B, and the arrangement mode of the shallow stepped cavities B and the deep stepped cavities B is obtained by rotating the arrangement mode of the shallow stepped cavities A and the deep stepped cavities A along the center line of the mixed flow channel by 180° under the perspective angle.

3. The double-layered composite micro-reaction channel plate with stereoladder channels according to claim 2, characterized in that: The depth of the mixed flow channel is 0.4-1.2mm.

4. The double-layer composite micro-reaction channel plate with three-dimensional stepped channel according to claim 3, characterized in that: The depth of the shallow stepped cavities A and the shallow stepped cavities B relative to the mixed flow channel is 0.1-0.3mm; The depth of the deep stepped cavities A and the deep stepped cavities B relative to the mixed flow channel is 0.2-0.6mm.

5. The double-layered microchannel plate with stereoladder channels according to claim 4, wherein the microchannel plate is characterized by: The depth of the mixed flow channel is 0.5-0.6mm.

6. The double-layer composite micro-reaction channel plate with three-dimensional stepped channel according to claim 5, characterized in that: The depth of the shallow stepped cavities A and the shallow stepped cavities B relative to the mixed flow channel is 0.15-0.2mm; The depth of the deep stepped cavities A and the deep stepped cavities B relative to the mixed flow channel is 0.25-0.3mm.

7. The double-layered microchannel plate with stereoladder channels according to any one of claims 1 to 6, wherein: the microchannel plate is made of a material selected from the group consisting of silicon, glass, and quartz. The first fluid pre-heat exchange channel, the second fluid pre-heat exchange channel and the mixed flow channel are in the form of zigzag.

8. The double-layered microchannel plate with stereoladder channels according to any one of claims 1-6, wherein the plate is made of a material selected from the group consisting of glass, quartz, silicon, and polymers. The heat exchange channel A and the heat exchange channel B are in the form of zigzag, and the upper channel plate and the lower channel plate are further provided with a heat exchange liquid inlet and a heat exchange liquid outlet, and the bottom of the heat exchange channel A and the heat exchange channel B is distributed with a plurality of flow guide strips along the flow direction; the two ends of the heat exchange channel A and the heat exchange channel B are in communication with the heat exchange liquid inlet and the heat exchange liquid outlet respectively.

9. A microchannel reactor comprising a double-layered composite microchannel plate with stereoladder channels, characterized in that The upper cover plate, the upper channel plate and the lower channel plate are superimposed on each other from top to bottom. ​ ​ The lower channel plate of the double-layer composite micro-reaction channel plate containing stereoscopic ladder channels according to any one of claims 1-8; The lower cover plate.

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