CN115554942A - Micro-reactor for intensifying mixing process - Google Patents

Abstract

The invention relates to a micro-reactor for intensifying a mixing process, which comprises a plurality of mixing units sequentially connected along a longitudinal direction, wherein each mixing unit comprises an outer shell, the side profile of the outer shell comprises an axially symmetric arc-shaped upstream section and a linear downstream section which are oppositely arranged, the upstream section and the downstream section are smoothly connected, and a flow cavity is formed in the outer shell in an enclosing manner.

Description

Micro-reactor for intensifying mixing process

Technical Field

The invention relates to the technical field of micro chemical engineering, in particular to a micro-reactor.

Background

A microreactor is a micro-device that can be used to perform chemical reactions or mixing of substances, manufactured in a solid matrix by means of special micro-fabrication techniques. "micro" in microreactors means that the channels for the process fluids are typically on the micron scale, and there are presently also schemes that reach the millimeter scale.

The micro-reactor has the characteristics of small volume, large specific surface area, high reaction efficiency, accurate control and the like, has wide application prospect for the application of conditions including violent exothermic reaction, unstable reaction of intermediate or product, quick reaction with strict proportioning requirement, high temperature and high pressure and the like, and is expected to become a high-efficiency and safe revolutionary technology of the chemical industry.

Due to the characteristics of small size, mostly laminar flow state, obvious interface action and the like of the microreactor, the flow and transfer characteristics of the microreactor are greatly different from those of a conventional reactor, and the design concept is also different. At present, the micro-reactor mainly adopts two static mixing modes, wherein external power is not relied on, and reactant mixing is completed only by utilizing the channel structure design and the control of fluid flow property, so that the micro-reactor has the characteristics of stability, simplicity, convenience, wide application range and the like.

Fig. 1 shows a prior art microreactor 100. The microreactor comprises a plurality of mixing units connected in series. Each mixing unit has an overall circular-arc-shaped outer contour 101, in particular a full-arc-shaped contour on its sides, and an inlet and an outlet are formed at opposite ends of the outer contour, respectively. The outlet 102 of the single mixing unit forms an arcuate constriction such that the cross-section of the outlet decreases progressively in the direction of fluid flow. In addition, the outlet of a single mixing unit is completely embedded or buried in the inlet of the next adjacent mixing unit, so that the two mixing units are tightly connected and have certain overlapped parts in the outline. In addition, an arc-shaped first blocking portion 103 and a circular second blocking portion 104 are further provided in the single mixing unit, and the second blocking portion 104 is closer to the outlet of the mixing unit with respect to the first blocking portion 103. Therefore, when entering the immediately following mixing unit through the outlet 102 of the previous mixing unit, the fluid will impact on the first blocking part 103, and then flow to both sides and finally flow to the outlet of the mixing unit. Second barrier 104 forms a "stagnant zone" upstream thereof such that sediment in the fluid does not continue to flow downstream.

In this microreactor, the fluid easily forms a vortex inside the first barrier section 103, and the residence time of the fluid is prolonged. This can result in a very large pressure drop of the fluid through microreactor 100. In addition, as shown in fig. 1, the distance between the outside of the first barrier 103 and the outer contour 101 is gradually increased in the fluid flow direction. Thus, the fluid will gradually diverge there. This can make it difficult to mix the fluids thoroughly.

Fig. 2 shows another prior art microreactor 200. The micro-reactor comprises a plurality of mixing units which are connected in sequence. The outer contour 201 of each mixing unit has an arcuate contour only at the upstream end and the arcuate contour does not extend to the side. The sides of outer contour 201 are formed by fold lines at both ends. An inlet and an outlet are formed at opposite ends of the outer contour 201, respectively. The outlet 202 of the single mixing unit is a straight channel of constant cross-section. In addition, a first stopper 203 in a zigzag shape and a second stopper 204 in a circular shape are provided in a single mixing unit. The second barrier 204 is closer to the outlet of the mixing unit than the first barrier 203. Therefore, when entering the next mixing unit through the outlet 202 of the previous mixing unit, the fluid will impact on the first blocking portion 203, flow to both sides, and finally flow to the outlet of the mixing unit.

In this microreactor, the polygonal side profile of the outer contour 201 causes a large energy loss of the fluid and an increase in pressure drop. In addition, this also causes an increase in the ineffective mixing area at the rear side of the first barrier 103, resulting in a deterioration in the impact effect and a decrease in mixing efficiency.

In addition, for both microreactors described above, the configuration of the outlet 102, 202 of the mixing unit results in a certain tendency of the fluid to "return" after impacting the first blocking section 103, 203. This is disadvantageous for the mixing efficiency and increases the pressure drop.

Experiments were performed under liquid-liquid mixing conditions for the microreactor in fig. 2. Water and isooctanol were transported from the inlet at a velocity of 0.3m/s. Fig. 3 and 4 show the mixing regime and the pressure regime, respectively, of the microreactor of fig. 2. As can be seen from fig. 3, the microreactor requires that the fluids pass through at least 8 mixing units to achieve efficient mixing between the fluids. Effective mixing is defined herein as a difference in concentration of less than 0.5% between the left and right sides of the cavity in the mixing unit. As can be seen from fig. 4, the pressure drop of the fluid in the microreactor through the 8 mixing units to effective mixing is approximately 8680 pa.

Similarly, experiments were performed under gas-liquid mixing conditions for the microreactor in fig. 2. Water and air were delivered from the inlet at a velocity of 0.3m/s. The experimental result shows that the micro-reactor needs at least 6 mixing units to realize effective mixing of the fluids, and the pressure drop is about 2.3 kilopascal.

Disclosure of Invention

The present invention proposes a microreactor for intensifying the mixing process, which can be used to avoid or at least diminish at least one of the above problems.

According to the invention, a microreactor is provided, comprising a plurality of mixing units connected in series in the longitudinal direction, each mixing unit comprising an outer shell, the lateral profile of the outer shell comprising axially symmetric, oppositely arranged circular arc-shaped upstream sections and linear downstream sections, the upstream and downstream sections being connected smoothly, a flow chamber being enclosed in the outer shell.

By the smooth fit of the straight downstream segment with the circular arc upstream end. This allows the energy loss of the fluid flowing therethrough to be reduced compared to a dogleg profile, thereby effectively reducing the pressure drop. This is more effective in avoiding the formation of eddies and back mixing within the flow chamber than is possible with a generally curved profile. This allows a more controlled residence time of the fluid in the microreactor and an efficient increase of the mixing efficiency of the microreactor, even under the influence of the pulses of the feed pump.

In a preferred embodiment, each mixing unit further comprises a first blocking portion disposed within the flow chamber, the first blocking portion comprising a rectilinear middle section extending transversely to the longitudinal direction and rectilinear edge sections connected at both ends of the middle section, the edge sections being inclined upstream with respect to the middle section to form a break angle between the edge sections and the middle section.

In a preferred embodiment, the axially symmetrically opposite linear downstream sections are inclined relatively close downstream; the rectilinear downstream segment is arranged parallel to the edge segment so as to maintain a constant cross-section of the passage between the downstream segment and the edge segment.

In a preferred embodiment, the upstream end of the edge segment is aligned with the upstream end of the straight downstream segment.

In a preferred embodiment, the longitudinal length of the first barrier is 1/3 to 1/2 of the longitudinal length of the flow chamber.

In a preferred embodiment, the opposite ends of each mixing unit in the longitudinal direction form an inlet portion and an outlet portion, respectively, both of which are communicated to the flow chamber and communicated with the flow chambers of the other adjacent mixing units; the middle section of the first blocking portion is opposite to the inlet portion, and the longitudinal size of the middle section is not more than 2 times of the maximum cross-sectional size of the inlet portion.

In a preferred embodiment, the angle between the opposing edge segments is not less than 50 °.

In a preferred embodiment, the opposite ends of each mixing unit in the longitudinal direction form an inlet and an outlet, respectively, both of which are communicated to the flow chamber and communicated with the flow chambers of the adjacent other mixing units; wherein the inlet part forms an expanding channel gradually expanding in a longitudinal direction to the downstream direction, and the outlet part forms a necking between the linear downstream section of the mixing unit and the expanding channels of the inlet parts of other adjacent mixing units.

In a preferred embodiment, the cross-sectional dimension of the narrowest point of the constriction is not less than 1/4 of the largest cross-sectional dimension of the inlet portion.

In a preferred embodiment, the inlet portion has a maximum cross-sectional dimension of between 100 and 1000 microns.

Drawings

The invention is described in more detail below with reference to the accompanying drawings. Wherein:

FIG. 1 shows a schematic block diagram of a prior art microreactor;

FIG. 2 shows a schematic block diagram of another prior art microreactor;

FIG. 3 shows a mixing efficiency diagram of the microreactor of FIG. 2 in liquid-liquid mixing;

FIG. 4 shows a schematic diagram of the pressure drop of the microreactor in FIG. 2 upon liquid-liquid mixing;

FIG. 5 shows a schematic block diagram of a microreactor according to an embodiment of the present invention;

FIG. 6 shows an enlarged partial view of the microreactor of FIG. 5;

FIG. 7 shows a schematic liquid flow path diagram of the microreactor of FIG. 5 upon liquid-liquid mixing;

FIG. 8 shows a mixing efficiency diagram of the microreactor of FIG. 5 in liquid-liquid mixing;

FIG. 9 shows a schematic diagram of the pressure drop of the microreactor of FIG. 5 during liquid-liquid mixing;

fig. 10 shows a mixing efficiency diagram of the microreactor in fig. 5 in gas-liquid mixing;

FIG. 11 shows a schematic diagram of the pressure drop of the microreactor in FIG. 5 upon gas-liquid mixing;

FIG. 12 shows a schematic diagram of the liquid flow paths of the microreactor of FIG. 5 during nitration.

In the drawings, like parts are provided with like reference numerals. The figures are not drawn to scale.

Detailed Description

The invention will be further explained with reference to the drawings.

In the present invention, "longitudinal direction" refers to a direction in which a fluid generally flows, and is understood as an up-down extending direction in a paper plane in fig. 6, for example. Accordingly, "transverse" refers to a direction perpendicular to the "longitudinal" direction, and is understood as a left-right extending direction in the paper plane in fig. 6, for example.

In the present invention, "upstream" refers to a side on which a fluid is supplied, and "downstream" refers to a side to which the fluid flows, in contrast.

Fig. 5 shows an embodiment of a microreactor 300 according to the present invention. The microreactor 300 comprises a plurality of mixing units 310 connected in series in the longitudinal direction. In fig. 5 an embodiment of 20 mixing units 310 is shown. However, it should be understood that more or fewer mixing units 310 may be provided as desired. The microreactor 300 further comprises a fluid inlet channel 304 connected upstream of a first one of the successively connected mixing units. The fluid inlet channel 304 communicates with the first inlet branch 301 and the second inlet branch 302, respectively. The fluid can enter the fluid inlet channel 304 via the first inlet branch 301 and the second inlet branch 302 and from there enter the mixing unit 310 for mixing. The fluid here may be a gas, a fluid, or any other suitable flowable medium. The microreactor 300 further comprises a fluid outlet channel 303 connected downstream of the last of the successively connected mixing units for delivering the fluid mixed (even reacted) in the microreactor 300 for further processing or use etc.

Fig. 6 shows a close-up view of microreactor 300 in fig. 5. As shown in fig. 6, the mixing unit 310 is formed as a planar mixing unit including an outer case of a flat form. The outer shell is configured to be axially symmetrically arranged along the longitudinal axis and thus comprises two oppositely disposed side profiles, a first side profile and a second side profile. Each lateral profile comprises an upstream segment 312 of circular arc shape and a downstream segment 313 of rectilinear shape. The straight downstream section 313 is smoothly connected to the circular upstream section 312. The two oppositely disposed upstream sections 312 may be configured to be relatively inclined in a downstream direction, thereby enabling the outer shell to form a generally inverted-heart shape. A flow chamber is enclosed within the outer housing.

As also shown in fig. 6, an inlet portion and an outlet portion are provided at longitudinally opposite ends of the outer housing, respectively. The inlet portion and the outlet portion are both in communication with the flow chamber. In addition, the inlet portion may be formed as an expansion passage 314 gradually expanding toward downstream in the longitudinal direction. The profile of the expanding channel 314 is a straight profile. Thus, fluid may enter the flow chamber in a divergent fashion through the expanding channel 314. The outlet portion may be formed as a constriction 315 connected between the flow chamber of the preceding mixing unit and the expansion channel 314 of the inlet portion of the following mixing unit. Thereby, the respective mixing units 310 are integrally formed in a shape like a "spade".

As shown in fig. 6, the mixing unit 310 further includes a first blocking portion 311 disposed within the flow chamber. It should be understood that the first blocking portion 311 may be formed by a solid block, or a through hollow of the outer housing as shown in fig. 5, as long as it can block the fluid from flowing therethrough.

The first barrier 311 comprises a middle section 311B arranged laterally centrally within the flow chamber. The middle section 311B extends transversely to the diverging passageway 314 of the inlet section and is in a straight configuration. The first stop 311 further includes straight edge segments 311A and 311C connected at opposite ends of the middle segment. The free ends of the edge segments 311A and 311C are each inclined more upstream relative to the middle segment 311B such that a dog-ear is formed between the edge segments 311A and 311C and the middle segment 311B. Preferably, the angle between the two edge segments 311A and 311C is not less than 50 °.

In addition, as also shown in fig. 6, a rectilinear downstream segment 313 may be arranged parallel to the above-mentioned edge segments 311A and 311C, so as to form between them an advancement channel of constant section. The advancement channels are symmetrically arranged, wherein a first advancement channel is defined between the first lateral profile and the first blocking portion 311, and a second advancement channel is defined between the second lateral profile and the first blocking portion 311. In addition, edge segments 311A and 311C are aligned with respective downstream segments 313 at the upstream end. The distance between the edge segments 311A and 311C and the circular arc shaped upstream end 312 of the outer housing also is such that the cross section of the backflow passage formed therebetween remains relatively constant. This allows the fluid to remain relatively concentrated as it flows through the reverse flow path and the forward flow path, thereby providing a better basis for downstream fluid mixing, providing more intense impingement of the fluids during mixing, and further improving the efficiency of mixing between the fluids. In addition, the counterflow channel is designed relatively much, which makes it less likely that "dead zones" will form there, or that the area of "dead zones" formed will be relatively small.

The longitudinal dimension of the middle section 311B is not more than 2 times the maximum cross-sectional dimension of the expanding channel 314. In addition, the edge sections 311A and 311C are tapered in a direction toward the free end. The longitudinal length of the first blocking part 311 is 1/3 to 1/2 of the longitudinal length of the entire flow chamber. The so-called "second barrier" provided immediately downstream of the first barrier in the conventional solution may no longer be provided between the downstream of the first barrier 311 and the outlet. That is, a mixing region is formed in the entire region between the downstream of the first barrier 311 and the upstream of the constriction 315 of the outlet portion. Since the first barrier 311 occupies a greater longitudinal length of the entire flow chamber, the fluid is more strongly guided by the downstream section 313 and the first barrier 311, and there are fewer "dead zones" within the flow chamber (especially the mixing zone). This can improve the liquid hold-up and throughput of microreactor 300.

The overall lateral dimension of the mixing unit 310 may be between 100 microns and 1 cm, and the overall thickness may be between 100 microns and 1000 microns. The cross-sectional dimension of the fluid inlet channel 304 and the maximum cross-sectional dimension of the expanding channel 314 of each inlet portion may be between 100 and 1000 microns, preferably between 100 and 500 microns. The cross-sectional dimension of the narrowest portion of the constriction 315 is no less than 1/4 of the dimension of the fluid inlet passageway 304. The above dimensional design facilitates adjustment of the relative balance between improved mixing efficiency and reduced pressure drop. With the above design, the transfer area (specific surface area) of the microprocessor 300 can reach up to about 50000m ² /m ³ 。

The microreactor 300 may be used as a reactor or a mixer, and may be combined with a heat exchange unit, a collection unit, or other reaction/mixing units to perform a complete set of functions. It should be understood that in addition to microreactor 300 as described above, additional pumps, conduits, flow meters, valves, control systems, etc. may be provided to effect mixing and reaction of the fluids. The microreactor 300 can be used for a single-phase system, a gas-liquid system, a liquid-liquid system, and the like, and can also be used for a solid-containing multiphase system with low solid content and small hometown size. In addition, the microreactor 300 of the present invention is particularly suitable for reactions with severe heat release, unstable intermediates or products, strict proportioning requirements, and harsh conditions such as high temperature and high pressure, such as sulfonation, diazotization, halogenation, oxidation, nitration, epoxidation, hydrogenation, nanomaterial preparation, pharmaceutical processes, and the like.

With regard to the microreactor 300 of the present invention, when the fluid passes through the constriction 315 of the outlet portion of the previous mixing unit, passes through the divergent channel 314 of the inlet portion, and re-enters the flow chamber, the fluid can be caused to strike the first blocking portion 311 at a high speed. Since the first barrier 311 is of a zigzag type and the flow pattern of the fluid is dispersed, the fluid can rapidly change its direction laterally to flow toward the reverse flow path. In the region upstream of the first barrier 311, a highly turbulent, high velocity differential flow state may be formed, thereby promoting mixing between the fluids. Meanwhile, the fluid cannot return in the original way, or the vast majority of the fluid cannot return in the original way. This avoids "back-mixing" and allows the residence time of the fluid to be kept relatively constant, thereby resulting in a more controlled flow of the fluid and helping to accurately control and enhance the mixing and reaction process.

In addition, when the fluid passes around the edge sections 311A and 311C of the first barrier 311 in the reverse flow path, the fluid moves substantially along an arc-shaped trajectory, and can be locally disturbed by the clamps at the edge sections 311A and 311C to further enhance the mixing effect. Then, the two flows are impacted and mixed together through the linear advancing channel, and strong mixing can be formed. The mixed fluid may exit the mixing element through the constriction 315 and enter the next mixing element for further mixing through the diverging passage of the inlet portion of the latter mixing element. This configuration increases the local flow rate, shear rate and turbulence level, while reducing the mass transfer distance and further enhancing the mixing and/or reaction process.

The advantageous effects of microreactor 300 of the present invention will be further illustrated by a number of examples.

Example 1

The mixing efficiency of microreactor 300 of the present invention was tested using a system containing a fluorescent dye. The mixing efficiency can be measured by measuring and calculating the mixing factor at the outlet. The specific calculation formula is as follows:

where ψ denotes a mixing factor, SD _AIOD Is the relative standard deviation, SD, of the exit concentration of the target _AIOD，0 Relative standard deviation of concentrations prior to mixing. Closer to 0 this mixing factor ψ represents a poorer mixing effect, and closer to 1 represents a better mixing effect.

An aqueous safranin solution and water are respectively introduced into the microreactor 300 of the present invention through a first inlet branch 301 and a second inlet branch 302, and the flow rates entering the first inlet branch 301 and the second inlet branch 302 are both 20L/min. The outlet was determined to have a mixing factor psi of 0.85 (about 0.6 for the prior microreactor 200 of fig. 2) and a pressure drop of about 0.1MPa. This demonstrates that microreactor 300 of the present invention is capable of achieving good fluid mixing without causing excessive pressure drop.

Example 2

A liquid-liquid mixing efficiency experiment was performed for microreactor 300. Microreactor 300 is generally shown in fig. 5 as a microchannel formed in a stainless steel-based face plate by an engraving machine having a depth of about 500 microns. Water and isooctyl alcohol are respectively introduced into the first inlet branch 301 and the second inlet branch 302, feeding is realized by adopting a precision injection pump, and the inlet flow rate is controlled to be about 0.3m/s. The cross-sectional dimension of the fluid inlet channel 304 is 550 microns. The maximum transverse dimension of the mixing unit 310 is about 3.4 mm and the longitudinal dimension (excluding the inlet and outlet portions) is about 2.6 mm. The diverging passage 314 of the inlet section faces the first blocking section 311 in the flow chamber. The middle section 311B of the first barrier 311 has a longitudinal dimension of about 200 microns and a transverse dimension of about 1 mm. The edge segments 311A and 311B of the first barrier 311 each have a length of about 800 microns and a width that tapers from 200 microns to 100 microns. The upstream end 312 of the outer shell in the form of a circular arc is 150 microns (significantly less than the counter-flow distance in the center of the prior art to reduce the inefficient mixing area) counter-current to the counter-flow path formed by the edge segments 311A and 311B. The minimum cross-sectional dimension of the constriction 315 in the outlet portion is 200 microns.

The above-described microreactor 300 was used to perform liquid-liquid mixing experiments under the same experimental conditions as those for the conventional microreactors shown in fig. 2 to 4. Fig. 7 to 9 show the corresponding experimental results. As shown in fig. 7, the velocity vector distribution of the liquid-liquid mixing process of the microreactor 300 is gradually symmetrical and uniform, and the parallelism and consistency of the vector arrows of the fluid flow are high before the intensive impingement mixing of the mixing chamber. This illustrates that the velocity vector distribution is highly controllable in the mixing unit 310 of the microreactor 300. This facilitates accurate anticipation and control of the mixing effect. As shown in fig. 8, microreactor 300 allows for efficient mixing of fluids after 4 mixing units. Figure 9 shows that the pressure drop for the fluid passing through the 4 mixing units to effective mixing is about 8080 pa.

Experiments have shown that the microreactor 300 of the present invention can achieve efficient mixing of fluids with fewer mixing units 310. That is, compared to the prior art microreactor 200 of fig. 2, the microreactor 300 of the present invention can significantly improve mixing efficiency, shorten mixing time, and thus reduce the number of mixing units required, while maintaining low pressure drop and high throughput, allowing a smaller microreactor volume.

Example 3

The same microreactor 300 as in example 2 was used to carry out a mixing reaction of methyl chloride and salicylic acid. The experiment was carried out with methyl chloride plus 25% salicylic acid at 22MPa, 350K. The results show that the reaction time required is about 220s, the yield is 99%, and the yield is increased by 1% compared with the conventional method which requires 10h of reaction time. In addition, the micro-reactor 300 obviously shows the advantages of simple operation, low cost, greatly reduced required space and the like in the experimental process.

Example 4

A gas-liquid mixing efficiency experiment was performed for the microreactor 300. Microreactor 300 is generally shown in fig. 5 as having an overall thickness (depth) of about 500 microns. The maximum transverse dimension (width) of the flow chamber is about 4 mm and the longitudinal dimension (excluding the inlet and outlet portions) is about 3 mm. The diverging passage 314 of the inlet section faces the first blocker 311 in the flow chamber. The middle section 311B of the first barrier 311 has a longitudinal dimension of about 250 microns and a transverse dimension of about 1.2 millimeters. The edge segments 311A and 311B of the first barrier 311 each have a length of about 1 mm and a width reduced from 250 microns to 150 microns. The upstream end 312 of the outer shell in the shape of a circular arc is 200 microns upstream of the counterflow channel formed by the edge segments 311A and 311B (significantly less upstream than the counterflow distance in the center of the prior art to reduce the region of inefficient mixing). The minimum cross-sectional dimension of the constriction 315 in the outlet portion is 250 microns.

The gas-liquid mixing experiment was performed using the microreactor 300 described above. The first inlet branch 301 and the second inlet branch 302 respectively convey deionized water and air, the operation temperature is 298K, and the viscosity is 8.9 multiplied by 10 ^-4 Pa · s, surface tension coefficient 0.07N · m-1, and the entry flow rate were all 0.3m/s. Fig. 10 to 11 show the corresponding experimental results. As shown in fig. 10, microreactor 300 allows for efficient mixing of fluids after 4 mixing units. Figure 11 shows that the pressure drop of the fluid after 4 mixing units is about 2.3 kpa.

Compared with the experimental result of gas-liquid mixing of the prior microreactor in fig. 2, the microreactor 300 can greatly improve the mixing efficiency under the condition of keeping low pressure drop and large flux, and has advantages in the aspects of mixing time, the number of required mixing units, the overall volume and the like.

Example 5

A nitration reaction efficiency experiment was conducted for the microreactor 300 of the present invention. The reactor is made of stainless steel, and the heat exchanger is arranged on the outer layer to realize the closed-loop circulating flow of the heat transfer liquid so as to realize the integration of mixing and heat transfer.

The existing general process for preparing isooctyl nitrate is to drop isooctyl alcohol into prepared sulfuric acid, nitric acid mixed acid for nitration, and then to obtain the finished product after acid washing, alkali washing and water washing refining. Because the reaction is a strong exothermic reaction, in order to avoid the risk of thermal runaway, the feeding speed of the traditional kettle type reactor is very slow, and the reaction process needs more than 1 hour.

Isooctyl nitrate was prepared by reaction using microreactor 300. Not only can the mixing and reaction rate be enhanced, but also the heat transfer rate can be obviously improved, and the process safety is improved. Fig. 12 shows the liquid flow paths during the experiment, which shows that the microreactor 300 can make the distribution of the liquid phase during the experiment uniform and controllable, and the transfer efficiency is high. In addition, the reaction residence time of the fluid can be shortened to be within 2 minutes from the traditional 1 hour or more, and meanwhile, the purity of the product is improved by about 3 percent, so that the method has obvious advantages.

While the invention has been described with reference to a preferred embodiment, various modifications may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In particular, the technical features mentioned in the embodiments can be combined in any way as long as there is no structural conflict. It is intended that the invention not be limited to the particular embodiments disclosed, but that the invention will include all embodiments falling within the scope of the appended claims.

Claims (10)

1. The utility model provides a microreactor, includes a plurality of mixing unit that connect gradually along longitudinal direction, and each mixing unit includes the shell body, the lateral part profile of shell body includes the convex upstream section and the downstream section of linear type of the relative setting of axial symmetry formula, upstream section and downstream section smooth connection enclose and form the flow chamber in the shell body.

2. The microreactor according to claim 1, wherein each mixing unit further comprises a first blocking portion disposed in the flow chamber, the first blocking portion comprising a linear middle section extending transversely to the longitudinal direction and linear edge sections connected at both ends of the middle section, the edge sections being inclined upstream relative to the middle section to form a break angle between the edge sections and the middle section.

3. The microreactor according to claim 2, wherein axially symmetrically opposed linear downstream sections are inclined in relatively close proximity downstream;

the straight downstream segment is arranged parallel to the edge segment so that the cross-section of the passage between the downstream segment and the edge segment remains constant.

4. The microreactor of claim 3 wherein the upstream end of the edge section is aligned with the upstream end of the straight downstream section.

5. The microreactor according to any of claims 2 to 4, wherein the longitudinal length of the first blocking section is 1/3 to 1/2 of the longitudinal length of the flow chamber.

6. The microreactor according to any one of claims 2 to 4, wherein opposite ends of each mixing unit in the longitudinal direction form an inlet portion and an outlet portion, respectively, both of which are communicated to the flow chamber and communicated with the flow chambers of the other adjacent mixing units;

the middle section of the first blocking portion is opposite to the inlet portion, and the longitudinal size of the middle section is not more than 2 times of the maximum cross-sectional size of the inlet portion.

7. Microreactor according to any of claims 2 to 4, wherein the angle between opposing edge sections is not less than 50 °.

8. The microreactor according to any one of claims 1 to 4, wherein opposite ends of each mixing unit in the longitudinal direction form an inlet portion and an outlet portion, respectively, both of which are communicated to the flow chamber;

wherein the inlet portion forms an expanding channel gradually expanding in a longitudinal direction downstream, and the outlet portion forms a constriction between the straight downstream section of the mixing unit and the expanding channel of the inlet portion of the adjacent other mixing unit.

9. The microreactor of claim 8 wherein the cross-sectional dimension of the narrowest portion of the constriction is not less than 1/4 of the largest cross-sectional dimension of the inlet portion.

10. The microreactor of claim 9 wherein the inlet portion has a maximum cross-sectional dimension of between 100 and 1000 microns.

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