JP6229647B2 - Taylor reactor - Google Patents

Description

    The present invention relates to a Taylor reactor.

  In order to produce micrometer-scale fine particles having a feature in the particle size distribution, a “growth method” using a chemical reaction of gas or solution is generally used. This growth method is a two-step process in which nuclei of fine particles are generated in the first stage and nuclei are grown in the second stage to obtain a desired particle diameter. In this “growth method” between solutions, it is important to control the concentration change at a local location where the feed solutions cause a chemical reaction.

  However, in a conventional stirring tank that is often used for the growth method, a) a dead zone is generated in the stirring tank, b) shear is weak, c) dwell time is non-uniform, and the like causes a chemical reaction. There is a drawback that the concentration of the supply liquid is not uniform in the region inside the agitation tank, and therefore fine particles having a desired particle size and particle size distribution may not be obtained.

In order to eliminate such drawbacks, the conventional technique of Patent Document 1 has proposed a method for controlling the growth of particles by using two Taylor reactors.
The prior art includes two units, a first-stage Taylor reactor that generates nuclei for reacting feed solutions and a second-stage Taylor reactor that performs crystal growth of particles. The flow state in the first-stage Taylor reactor forms a slightly slanted donut-shaped pseudo channel, and the feed solution runs in a spiral to cause a chemical reaction. As a result, it is described that the concentration change at the generation site of the chemical reaction is controlled, and the fine particles can be manufactured.

  However, in the prior art of Patent Document 1, since two Taylor reaction tubes are used, there is a problem that an installation space becomes large or it is difficult to perform a chemical reaction in order between the two Taylor reaction tubes. It was difficult to obtain a desired particle size and particle size distribution.

Furthermore, not only the above conventional example, but generally the Taylor reactor has the following problems.
As shown in FIG. 6, a general Taylor reaction apparatus has a stationary outer cylinder 101 and a rotating inner cylinder 102, and one end of a tank 110 that is a gap space between the outer cylinder 101 and the inner cylinder 102. A supply port 103 is attached to the other end, and a discharge port 104 is provided at the other end. When the solution is put into the tank 110 and the inner cylinder 102 is rotated, a Taylor vortex is generated in the tank 110. As shown in FIG. 7A, the Taylor vortex T is a donut-shaped swirling fluid, and each Taylor vortex T is an independent fluid. Then, the swirl direction around the inner cylinder is opposite to the adjacent Taylor vortex T, and the flow in the cross section of each Taylor vortex T is also opposite to each other as shown in FIG.

  Many such Taylor vortices are generated adjacent to each other in the tank 110, and the solution itself is gradually moved to the next Taylor vortex, and the solution is agitated to gradually grow particles. Particles of the desired particle size are discharged.

  However, since the solution before the reaction is diffused throughout the reactor due to mixing between Taylor vortices, particles that flow out (short pass) with a short residence time are generated. If the residence time is short, the crystal growth of the particles flows out with insufficient, and there is a problem that fine particles having an undesirably small particle diameter are discharged.

In order to solve this problem, the inventor has studied to suppress a short path by introducing a shielding plate in the gap space. According to this method, it is possible to reduce the short path, but if a shielding plate is provided in the vicinity of the supply port 103, diffusion of the supply liquid may be hindered and an independent mixed region may be generated. In this case, the problem arises that the solution concentration in the independent mixing region is likely to be higher than the average concentration, producing fine particles having an undesired particle size. As a result, the particle size distribution is widened and uniform particles are obtained. The problem of not being able to occur occurred.
In order not to cause the above problem, it is necessary to limit the supply amount of the supply liquid to such an extent that the solution concentration in the vicinity of the supply port does not increase.

JP 2011-83768 A

  In view of the above circumstances, an object of the present invention is to provide a Taylor reactor capable of obtaining a desired particle size and particle size distribution without limiting the supply amount of the supply liquid.

The Taylor reactor of the first invention comprises an outer cylinder and an inner cylinder that rotates in the outer cylinder, and a gap space formed between the outer cylinder and the inner cylinder is a Taylor vortex generation region, A Taylor reactor equipped with a supply port for supplying the pre-reaction solution from the outside to the gap space at one end in the longitudinal direction of the outer cylinder, and a discharge port for discharging the solution after the reaction from the gap space to the outside at the other end in the longitudinal direction In the clearance space, a shielding plate that suppresses the flow between Taylor vortices is provided, and the shielding plate is closer to the discharge port than an intermediate position between the supply port and the discharge unit. It is characterized by being installed only in the area.
In the Taylor reactor of the second invention, in the first invention, a plurality of the shielding plates are provided, and the interval between adjacent shielding plates is an integer of x where the height of the gap space is x. It is characterized by being double.
The Taylor reactor according to a third aspect of the invention is characterized in that, in the first or second aspect of the invention, the shielding plate is an annular rib and is formed so as to protrude inward from the inner wall surface of the outer cylinder. And
A Taylor reactor according to a fourth aspect of the present invention is characterized in that, in the first or second aspect, the shielding plate is an annular rib and is formed to protrude outward from the outer peripheral surface of the inner cylinder. to.

According to the first aspect of the present invention, since there is no shielding plate in the gap space near the supply port, flow between adjacent Taylor vortices is likely to occur, and an independent mixing region is unlikely to occur, so local concentration does not increase. . On the other hand, since the contact area between the Taylor vortices can be reduced by the shielding plate at the part near the discharge port, the diffusion of the solution between the Taylor vortices is suppressed, and the proportion of particles flowing out with a short residence time is reduced. be able to. In this way, an increase in local concentration is suppressed in the first half of the reaction and a short path is suppressed in the second half, so that particles having a desired particle size and particles having a small particle size distribution are finally obtained.
According to the second invention, when the interval between the shielding plates is an integral multiple of the height x of the gap space, the shielding plates partition the adjacent Taylor vortices without destroying the Taylor vortices. For this reason, the stirring action in the same Taylor vortex can be continued and particle growth can be performed in the same Taylor vortex.
According to the third invention, since a gap is formed between the shielding plate and the inner cylinder, particle movement is possible through the gap between the inner cylinder while suppressing contact between adjacent Taylor vortices. Continuous stirring with the Taylor vortex can be performed.
According to the fourth invention, since a gap is formed between the shielding plate and the outer cylinder, particle movement is possible through the gap between the outer cylinders while suppressing contact between adjacent Taylor vortices. Continuous stirring by Taylor vortex can be performed .

It is a section front view of Taylor reaction device A concerning a 1st embodiment of the present invention. It is a longitudinal cross-sectional perspective view of the Taylor reaction apparatus A shown in FIG. It is operation | movement explanatory drawing of a shielding board. It is a section front view of Taylor reaction device B concerning a 2nd embodiment of the present invention. 3 is a graph showing an average residence time in a Taylor vortex in Example 1. FIG. It is explanatory drawing of a Taylor reaction apparatus more general than before. It is explanatory drawing of a Taylor vortex, Comprising: (A) is explanatory drawing of donut-like flow, (B) is explanatory drawing of a cross-sectional flow.

Next, an embodiment of the present invention will be described.
First, based on FIG. 1 and FIG. 2, the basic structure of the Taylor reaction apparatus A in this embodiment is demonstrated.
1 is an outer cylinder, and 2 is an inner cylinder. The outer cylinder 1 is constituted by a double cylinder from an outer plate 1a and an inner plate 1b, and the cavity 1c is used for passing a heating medium. The outer cylinder 1 is used in a stationary state.

  The inner cylinder 2 is a solid or hollow shaft, and is inserted into the outer cylinder 1 concentrically. It is connected to a drive source such as a motor and is rotatable. A gap space 10 is formed between the inner wall surface of the outer cylinder 1 and the outer surface of the inner cylinder 2, and the gap space 10 extends in the cylinder axis direction. That is, the doughnut-shaped gap space 10 is elongated. The gap space 10 is a Taylor vortex generation region and functions as a stirring tank.

A supply port 3 is provided at one end in the longitudinal direction of the outer cylinder 1 (right end in the drawing). As illustrated, it may be formed on the flange 5 or on the outer cylinder 1. The supply port 3 is an introduction port for supplying the pre-reaction solution to the gap space 10 from the outside.
A discharge port 4 is provided at the other end portion in the longitudinal direction of the outer cylinder 1 (left end portion in the drawing). The post-reaction solution in the gap space 10 is discharged from the discharge port 4.

  In the Taylor reactor A of the present embodiment, the Taylor vortex T can be generated in the solution filled in the gap space 10 by rotating the inner cylinder 2 at an appropriate rotational speed.

  As described above with reference to FIG. 7, the Taylor vortex T is a donut-shaped fluid that is generated in the gap space 10 and flows in the circumferential direction around the inner cylinder 2, and the direction of the circumferential flow is adjacent. The direction between the Taylor vortices T is opposite. Moreover, although it flows in the shape of a vortex within the cross section of each Taylor vortex T, the direction is also opposite between the adjacent Taylor vortices T.

Next, features of the Taylor reactor A according to the present invention will be described.
In the present invention, the shielding plate 6 that suppresses the flow of the solution between the Taylor vortices T adjacent to the gap space 10 is provided. In the first embodiment of FIGS. 1 and 2, the shielding plate 6 is an annular rib and is formed so as to protrude inward from the inner wall surface of the outer cylinder 1 (the inner plate 1b).

  One or a plurality of shielding plates 6 are provided, and the installation area f is an area near the discharge port 4 from an intermediate position c between the supply port 3 and the discharge port 4. Moreover, the shielding board 6 may be provided over the whole in the installation area | region f, and may be provided partially.

  As shown in FIG. 3, since the shielding plate 6 is inserted between adjacent Taylor vortices T, T, the thickness 6 of the shielding plate 6 should not be increased more than necessary. That is, if the thickness is thick, the width of the Taylor vortex T may be reduced, thereby inhibiting natural flow. However, if the shielding plate 6 is thin, the flow of the Taylor vortex T is not inhibited.

Further, it is desirable that a slight gap 6o is provided between the rib tip as the shielding plate 6 and the outer peripheral surface of the inner cylinder 2. The clearance dimension is a desirable value of about 1 mm in an apparatus in which the outer diameter of the inner cylinder 2 is 40 to 70 mm and the inner diameter of the outer cylinder 1 is 60 to 90 mm.
When there is such a numerical gap 6o, a small amount of fluid adjoins through the gap 6o while most of the fluid constituting the Taylor vortex T is suppressed from contacting between adjacent Taylor vortices T by the shielding plate 6. Since it flows into the Taylor vortex, it becomes possible for the solution to sequentially move through a plurality of stages of the Taylor vortex T from the supply port 3 to the discharge port 4. This movement allows the particles to grow sequentially.

In the present invention, the shielding plate 6 is disposed closer to the discharge port 4 than the middle between the supply port 3 and the discharge port 4, and is not disposed near the supply port 3.
There are two reasons for this.
First, when the shielding plate 6 is installed on the supply port 3 side, the diffusion of the supply liquid may be hindered and an independent mixing region may be formed in the vicinity of the supply port. High locally. This local high concentration hinders the uniformity of the particle size and is therefore to prevent it.
Second, by installing the shielding plate 6 near the discharge port, the short path of particles between adjacent Taylor vortices is suppressed, and the residence time in the same Taylor vortex is ensured to grow to a desired particle size. There is to make it.

  When a plurality of shielding plates 6 are provided, the distance d between the neighboring shielding plates 6 and 6 is preferably an integral multiple of x, where x is the height of the gap space. In other words, it is preferably an integral multiple of the width dimension of the Taylor vortex T. In this case, the distance d is the same width as the Taylor vortex T, or twice or three times.

As described above, when the interval between the shielding plates is an integral multiple of x, the shielding plate 6 on the Taylor vortex is not positioned, so that the Taylor vortex is not destroyed.
If the Taylor vortex is destroyed by the shielding plate 6, the short path is promoted and the residence time is shortened, so that only fine particles smaller than the desired particle size can be formed.
For example, the ratio of the particles flowing out by 1/10 of the average residence time is 25% or more, so that a desired particle size cannot be obtained and the particle size distribution is widened.

In the embodiment shown in FIGS. 1 and 2, the distance d between the three shielding plates 6 on the left side in the drawing is substantially the same as x, and the spacing between the shielding plates 6 placed apart on the right side is nd, That is, an example of an interval of twice or more is shown.
Of course, in the present invention, four shielding plates 6 are not essential, and there may be three or less, or only one. Further, it may be 5 or more.

  Even with the arrangement of the shielding plate 6 shown in FIGS. 1 and 2, it is possible to effectively suppress the contact between the adjacent Taylor vortices T and T without inhibiting the flow of the generated Taylor vortex T. That is, an appropriate amount of the reaction liquid flow between the adjacent Taylor vortices T is allowed, but a short path exceeding the limit can be suppressed, so that particle growth in the Taylor vortex is performed as desired.

The arrangement of the shielding plate 6 as described above can be calculated and determined within the scope of the present invention. And it is preferable to install so that the density | concentration which flows out by the time which starts injection | throwing-in of a solution and becomes 1/10 of average residence time may be reduced to 3/5 or less. In this case, fine particles having a desired particle size and a narrow particle size distribution can be produced.
As long as these conditions are satisfied, the number of shielding plates 6 may be one, or may be any plural number as shown in the figure. Furthermore, even if the installation position is on the discharge port 4 side from the intermediate position, the distance from the discharge port 4 may be arbitrarily selected. The selection of the installation position and the number of installations can be determined by design calculation or experiment.

Next, the Taylor reactor B of the second embodiment will be described.
In the Taylor reactor B of the present embodiment, the shielding plate 16 is an annular rib and is formed so as to protrude outward from the outer peripheral surface of the inner cylinder 2. Even in the shielding plate 16 having such a configuration, the function of suppressing the contact between the Taylor vortices T and T is the same. For this reason, since particle | grain movement is possible through the clearance gap between the outer cylinders 1, suppressing the contact between adjacent Taylor vortices T and T, continuous stirring by the multiple Taylor vortex T can be implemented.

Below, the usage method of the Taylor reaction apparatus A and B in this embodiment is demonstrated.
While the outer cylinder 1 is stationary, the inner cylinder 2 is rotated by a motor or the like. The solution before the reaction is caused to flow from the supply port 3, and the product after the chemical reaction is discharged from the discharge port 4.
In the present invention, the local concentration increase after 3 [min] can be suppressed to 3/5 or less with respect to the local concentration of the product in the vicinity of the supply port 3. Moreover, since the Taylor vortex is not broken, fine particles are hardly generated.

  The thing using one shielding board 6 in the Taylor reaction apparatus of FIG.

Using Microsoft spreadsheet software Excel, the flow state inside the Taylor reactor A is modeled, a plurality of shielding plates 6 are provided, and a solution having a concentration C [g / L] is supplied to the supply port 3 with a flow rate Q [ml. / min], the transition of the concentration of the solution inside each Taylor vortex was calculated. The space volume between the outer cylinder 1 and the inner cylinder 2 is V [ml], the liquid amount Q [ml / min] supplied from the supply port 3, and the distance from the supply port 3 to the discharge port 4 is L [cm]. . The average residence time τ is V / Q [min]. Since mixing inside the Taylor vortex T proceeds rapidly, a complete mixing state is set. The mixing between Taylor vortices was modeled on the assumption that the flow rate was changed by the diffusion flow rate Q ′ [l / min] due to the concentration gradient. If the cross-sectional area of the outer cylinder 1 and the inner cylinder 1 (or the cross-sectional area of the clearance space 10) is S [cm ² ] and the axial cross-sectional area of the shielding plate is S ′ [cm ² ], the insertion of the shielding plate 6 The diffusion flow rate Q ″ [l / min] is Q ″ = (S ′ / S) Q ′.

  In FIG. 5, a shield plate 6 having S` / S = 0.05 is installed near the supply port 3 at a distance of 1 [cm] from the supply port 3 as Comparative Example 1 and discharged as the vicinity of the discharge port 4. One installed at a distance of 1 [cm] from the outlet 4 is defined as Example 1, the solution concentration C = 1330 [g / L], and the space volume V between the outer cylinder 1 and the inner cylinder 2 V = 723 [ ml], amount of liquid Q supplied from the supply port 3 = 23 [ml / min], average residence time τ = 31 [min], diffusion flow rate Q ′ = 2 [l / min] due to concentration gradient, shielding plate 6 The transition of the concentration of the solution in the vicinity of the supply port 3 when the comparative example 1 and the example 1 are operated when the diffusion flow rate Q ″ = 100 [l / min] at the position where the is inserted is shown. In Comparative Example 1 in which the shielding plate 6 is installed at a distance of 1 [cm] from the supply port 3, the concentration rapidly rises to about 200 [g / L] in the time from 2 [min] immediately after the solution is charged to 3 [min] ] Increases to about 250 [g / L]. On the other hand, in Example 1 in which the shielding plate 6 is installed at a distance of 1 [cm] from the discharge port 4, the increase in concentration is suppressed to 150 [g / L] even if the time reaches about 3 [min]. It is possible. That is, in Example 1 in which the shielding plate 6 is installed at a distance of 1 [cm] from the discharge port 4, the increase in the concentration of the solution up to 3 [min] is increased from 250 [g / L] to 150 [g / L]. It was able to suppress to about 3/5.

1 outer cylinder 2 inner cylinder 3 supply port 4 discharge port
6 Shield plate

Claims (4)

An outer cylinder and an inner cylinder that rotates within the outer cylinder, and a gap space formed between the outer cylinder and the inner cylinder serves as a Taylor vortex generation region, and is externally attached to one longitudinal end of the outer cylinder. A reaction port provided with a supply port for supplying the pre-reaction solution from the gap space, and a discharge port for discharging the solution after the reaction from the gap space to the outside at the other end in the longitudinal direction,
The gap space is provided with a shielding plate that suppresses the flow between Taylor vortices, and the shielding plate is installed only in a region closer to the discharge port than an intermediate position between the supply port and the discharge unit. Taylor reactor characterized by being made. The said shielding board is provided with two or more sheets, The space | interval between adjacent shielding boards is an integral multiple of x when the height of the said clearance gap is set to x. Taylor reactor. 3. The Taylor reaction apparatus according to claim 1, wherein the shielding plate is an annular rib and is formed to protrude inward from an inner wall surface of the outer cylinder. 3. The Taylor reaction apparatus according to claim 1, wherein the shielding plate is an annular rib and is formed to protrude outward from the outer peripheral surface of the inner cylinder .