JP2020054974A - Reaction device - Google Patents

Abstract

To provide a reaction device capable of introducing a gas into a reaction liquid by a simple structure achievable at low cost, and capable of sufficiently reducing air bubble diameter by efficiently cutting the air bubble of the gas introduced into the reaction liquid.SOLUTION: There is provided a reaction device 1 having a reaction container 10 which is a cylindrical liquid phase accommodating tank, a stirrer 20 having a stirring axis 21 hung at a center of the reaction container 10 and a stirring blade 22 arranged in vertical to the stirring axis 21, and a gas blowing tube 30 which is a hollow tubular member hung at a position close to an outer periphery wall than the stirrer 20 in the reaction container 10 and has a gas blowing port in a lower end part, in which the stirrer 20 is a device capable of forming a liquid flow from the center of the reaction container 10 toward the outer periphery wall, the gas blowing tube 30 has baffle plates 31 extending vertically upward with a starting point of around the gas blowing port on an outside surface in a downstream direction of the liquid flow.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a reactor for introducing a gas into a liquid phase to cause a reaction.

  2. Description of the Related Art As a reaction device of a chemical plant or the like, a device that performs a chemical treatment by introducing a gas into a liquid phase such as a solution or a slurry in a reaction container while stirring to perform a chemical treatment.

  For example, Patent Document 1 discloses a shaft rotatable around a longitudinal axis of a container, and first and second radially extending impellers attached to the shaft and spaced apart in the axial direction. Disclosed is a mixing vessel provided with. Specifically, in this mixing vessel, the first impeller includes a plurality of curved blades operable to move fluid axially toward the second impeller, wherein the second impeller is axially The container includes a plurality of curved blades operable to move a fluid toward the first impeller, and a gas inlet is provided on a bottom surface of the container. In Patent Literature 1, by using a mixing container having such a configuration, a strong turbulent flow region is generated in the center of the mixing container, so that mixing of the liquid in the container can be easily controlled.

  However, in such a mixing container, when large bubbles are introduced from a gas blowing port provided largely in the center, it reaches the liquid level at the upper part of the mixing container before the bubble diameter is reduced in the mixing container. There's a problem. Therefore, even if such a mixing vessel is used for a chemical reaction, the amount of gas that does not contribute to the reaction increases, and the reaction efficiency decreases.

  It is important for the gas used for the chemical reaction in the reaction vessel to reduce the bubble diameter in the liquid phase in the reaction vessel, and the smaller the bubbles are, the larger the area of the gas-liquid interface becomes. For example, the amount of gas components dissolved in the liquid phase increases because the time during which the gas circulates and stays in the liquid increases, and as a result, the effect that the gas concentration in the liquid phase increases and the reaction efficiency is improved can be expected. In other words, in order to increase the efficiency of the reaction, it is important to convert the gas to be introduced into small bubbles in the liquid phase to maximize the amount of bubbles.

  As a technique for reducing the bubble diameter in the liquid phase, a method using a sparger (a diffuser tube), a method in which gas is blown under a stirring blade to separate bubbles by the blade, and the like are known. For example, it is known that, when the amount of gas blown is large, the stirring blade idles due to the flooding phenomenon, and the amount of gas dissolved into the liquid becomes small. There is disclosed a technique of using a ring sparger having a diameter larger than that of a wing to put blown air bubbles on a flow of liquid circulating in the apparatus.

  However, when applying a sparger to a reactor for introducing a gas, the pressure of the gas blown into the reactor from the sparger exceeds the sum of the internal pressure of the reaction vessel and the pressure loss of the sparger. Need to be pressed. Further, the sparger has a large pressure loss due to a small bubble outlet diameter, and thus has a problem in that the cost of the gas pressurizing equipment to be introduced becomes high particularly when the internal pressure of the reaction vessel is increased. Furthermore, depending on the reaction, reaction products including intermediates and residues after the reaction may become deposits and block small bubble outlets of the sparger. There is also a problem that is reduced. Due to such various problems, it was sometimes difficult to use a sparger for the reactor.

  In a reactor for introducing a gas, it is preferable to make the diameter of the gas blowing tube and the diameter of the outlet as large as possible in order to minimize pressure loss. However, it is well known that the bubble diameter of the bubbles discharged from the gas blowing tube depends on the outlet diameter of the gas blowing tube, and the bubble diameter increases when the pressure loss is minimized. An increase in the bubble diameter means a decrease in the area of the gas-liquid interface, which is not preferable. For this reason, there is a demand for a technique for reducing a large-diameter bubble discharged from a large outlet diameter having a small pressure loss into a small bubble diameter.

JP-T-2009-536095 JP 2014-113564 A

  The present invention has been made in view of such circumstances, and is a reaction apparatus that can introduce a gas into a reaction solution by a simple and low-cost structure, but is introduced into the reaction solution. It is an object of the present invention to provide a reactor capable of efficiently dividing large-diameter gas bubbles and reducing the gas bubble diameter sufficiently.

  The present inventors, in a reaction apparatus provided with a reaction vessel, a stirrer, and a gas blowing pipe, a baffle plate on an outer surface of the gas blowing pipe corresponding to a downstream side with respect to a liquid flow generated by the stirrer. By arranging, it has been found that bubbles released from the gas blowing tube can be efficiently divided, and the bubble diameter can be made sufficiently small, and the present invention has been completed.

  (1) A reaction vessel serving as a liquid phase storage tank, a stirrer vertically provided at the center of the reaction vessel, and a hollow provided vertically inside the reaction vessel closer to the outer peripheral wall than the stirrer. A gas blowing pipe having a gas blowing port at a lower end side of the reaction vessel, wherein the stirrer can form a liquid flow from the center of the reaction vessel to the outer peripheral wall. A reaction device, wherein a baffle plate extending vertically upward from the vicinity of the gas injection port is provided on an outer surface on a downstream side of the liquid flow in the gas injection pipe.

  According to the reaction device of (1), the gas is introduced into the reaction solution by a gas blowing tube formed of a hollow tubular member which has a simple structure and can be manufactured and used at low cost. The air bubbles introduced into the reaction solution can be efficiently divided by the baffle plate which is arranged with special consideration given to the relationship, and the diameter of the air bubbles can be sufficiently reduced.

  (2) The reaction device according to (1), wherein the baffle plate is formed of an elastic member that is elastically deformed by the liquid flow.

  According to the reaction device of (2), the baffle plate is formed of a member having appropriate elasticity, which is appropriately vibrated in the liquid flow, and the above-described bubble dividing effect of the invention of (1) is achieved. Can be further improved.

  (3) The baffle plate according to (1) or (2), wherein a width of the baffle plate extending from an outer side surface is larger on a vertically upper side than a vertically lower side of the baffle plate. Reactor.

  According to the reaction device of (3), by further improving the shape of the baffle plate to the above shape, the contact rate between the bubbles moving in the reaction solution and the baffle plate is increased, and (1) or (2) The effect of the above-described bubble dividing effect provided by the reaction device described in 1 above can be further improved.

  (4) In the baffle plate, only a part near the vertically lower end is joined to the outer surface of the gas blowing pipe near the gas blowing port, and the other part of the baffle plate extends vertically upward. The reaction device according to any one of (1) to (3), wherein the reaction device is disposed so that a distance from the outer surface of the gas blowing tube gradually increases.

  According to the reaction device of (4), the contact ratio between the bubbles moving in the reaction solution and the baffle plate is increased by further improving the joining mode of the baffle plate to the blowing tube to the above-described shape, Vibration can also be promoted. By these actions, the above-described bubble dividing effect provided by the reactor according to any one of (1) to (3) can be further improved.

  (5) The reaction device according to any one of (1) to (4), wherein the baffle plate has a curved surface at a vertically upper end.

  According to the reaction device of (5), the shape of the baffle plate is further improved so that the upper end near the liquid surface of the reaction solution has a curved surface. Rotational torque can be applied to the bubbles that have moved to the curved surface. Thereby, the separation of the bubbles progresses with higher efficiency due to a synergistic effect with the separation of the bubbles performed by the reactor according to any one of (1) to (4).

  ADVANTAGE OF THE INVENTION According to this invention, although it is a reaction apparatus which can introduce | transduce a gas into a reaction liquid by the structure which can be implement | achieved at a simple and low cost, the gas bubble introduce | transduced into the reaction liquid is divided efficiently. A reactor capable of sufficiently reducing the bubble diameter can be provided.

BRIEF DESCRIPTION OF THE DRAWINGS It is a longitudinal cross-sectional schematic diagram which shows the whole structure of the reaction apparatus of this invention. FIG. 2 is an enlarged view near an outlet (gas blowing port) of a gas blowing pipe in a portion A in FIG. 1 and is a diagram for explaining a positional relationship between a liquid flow and a baffle plate. It is a schematic diagram which shows an example of embodiment of a baffle board. It is a mimetic diagram showing other examples of an embodiment of a baffle board. It is the mimetic diagram seen from the downstream of a liquid flow about an example of an embodiment of a baffle board. It is the schematic diagram which looked at the further modification of embodiment of the baffle board from the downstream direction of the liquid flow.

  Hereinafter, a detailed description will be given of a reactor which is one of specific embodiments of the present invention, with reference to the drawings as appropriate. It should be noted that the present invention is not limited to the embodiments described below, and various changes can be made without changing the gist of the present invention.

  FIG. 1 is a schematic diagram of a longitudinal section of a reactor 1 according to one embodiment of the present invention. As shown in the figure, the reaction apparatus 1 includes a reaction vessel 10, a stirrer 20, and a gas blowing pipe 30. The reaction apparatus 1 accommodates a reaction liquid which is a liquid phase such as a liquid or a slurry in a reaction vessel 10 and introduces a gas contributing to a chemical reaction from a gas blowing pipe 30 in a state where a liquid flow is generated by a stirrer 20. Then, a chemical reaction is caused while stirring the gas in the liquid phase.

  The gas introduced into the reaction vessel 10 is not particularly limited, and for example, a gas such as air, nitrogen, or oxygen can be used in the reaction solution according to a desired chemical reaction.

[Reaction vessel]
The reaction vessel 10 is a cylindrical liquid phase storage tank having a generally circular cross section in a horizontal cross section. The reaction vessel 10 contains a reaction liquid therein to a predetermined height, and contains a chemical liquid in the reaction liquid. A reaction occurs. The reaction vessel 10 may have an open upper surface or may have a closed upper surface. The upper surface (when closed) and the bottom surface of the reaction container 10 are not limited to those each having a flat surface, and those having a curvature portion on the upper surface or the bottom surface in a vertical cross-sectional view cut in the vertical direction, or the upper surface or the bottom surface. It may have a curvature portion between the side and the side.

[mixer]
The stirrer 20 has a function of stirring the reaction solution contained in the reaction container 10. The stirrer 20 includes a stirrer shaft 21 that is suspended from an upper portion of the reaction vessel 10 and a stirrer blade 22 that is provided at a lower end position of the stirrer shaft 21 and that is perpendicular to the axial direction of the stirrer shaft 21. And

  The stirring shaft 21 is preferably arranged such that the center thereof coincides with the center of the circular reaction vessel in the cross-sectional view of the reactor 1. Thereby, the gas introduced into the reaction device can be more efficiently dispersed in the reaction solution.

  The stirring blade 22 rotates at a predetermined speed about the stirring shaft 21 as a rotation axis, so that the liquid flows from the center of the reaction vessel 10 toward the outer peripheral wall, preferably from the center toward the outer peripheral wall, in the reaction solution. Any liquid that can generate an obliquely downward liquid flow descending vertically downward may be used. The liquid flow along the direction of the arrow below the stirring blade 22 in FIG. 1, that is, such a liquid flow descending vertically downward from the center toward the outer peripheral wall, causes the entire reaction liquid Can be efficiently stirred. The stirring blade 22 is not limited to a specific shape or the like as long as it is a shape and an installation mode capable of generating such a liquid flow, but a plurality of stirring blades as shown in FIG. 1 are appropriately combined. Those having a propeller shape can be preferably used.

  The number of the stirring blades 22 is preferably plural, but is not particularly limited as long as the liquid flow of the above-described embodiment can be generated. Also, a plurality of such stirring blades 22 may be arranged at different vertical positions of the stirring shaft 21 so as to be vertically separated.

[Gas blowing pipe]
The gas blowing pipe 30 is for introducing a gas contributing to a chemical reaction into the reaction solution accommodated in the reaction vessel 10, and is a hollow tubular member having a gas blowing port at a lower end.

  As shown in FIG. 1, the gas blowing pipe 30 is inserted substantially perpendicularly to the surface of the reaction liquid at a horizontal position that is closer to the outer peripheral wall than the center of the reaction vessel 10 and does not interfere with the rotation of the stirring blade 22. Have been. Further, in the arrangement of the gas blowing pipe 30, the gas blowing port is disposed at a position where the strength (flow rate and / or flow velocity) of the liquid flow becomes as large as possible in relation to the above liquid flow. It is preferable to arrange them.

  The direction in which the gas is blown out from the gas blowing port at the lower end of the gas blowing pipe 30, that is, the direction perpendicular to the opening surface of the gas blowing port is directed vertically downward, or the angle difference from the direction. Are preferably oriented within a direction of 20 °. In the reaction solution, the gas blowing port is formed so as to be able to discharge gas in a direction within the above-mentioned angle range, so that the effect of dividing bubbles by the baffle plate 31 formed in the vicinity of the gas blowing port can be improved. It can be expressed efficiently and with higher accuracy. The effect of the baffle plate 31 on the separation of bubbles will be described later in detail.

(Baffle plate)
As shown in FIG. 1, a baffle plate 31 is provided on an outer surface of the gas blowing pipe 30. The main feature of the reaction apparatus 1 of the present invention is that the baffle plate 31 is installed in a manner optimized for the direction and strength of the liquid flow generated in the reaction vessel 10.

  The installation position and extension direction of the baffle plate 31 are optimized for the liquid flow in the reaction vessel 10. The specific installation position is such that, in the entire circumference of the outer surface of the gas blowing pipe 30, the range of the downstream half with respect to the direction of the flow of the reaction liquid (for example, the direction of the arrow in FIG. 1) is the baffle plate 31. Is the range to be installed.

  Here, the “downstream half range” of the outer surface of the gas blowing pipe 30 with respect to the direction of the liquid flow specifically refers to the area B (hatched portion) in FIG. 2 of the outer surface. Say that part. As shown in FIG. 2, when there is a liquid flow of the reaction liquid in the direction indicated by the arrow with respect to the center point of the gas injection pipe 30, the baffle plate 31 It is arranged in this area B by being installed on the outer surface of the gas blowing pipe 30 in such a direction that the angle formed with the line toward the direction becomes 90 ° or more.

  The range in which the baffle plate 31 on the outer surface of the gas blowing pipe 30 is to be installed (the range of the downstream half with respect to the direction of the liquid flow of the reaction liquid) is such that the liquid flow direction is from the center of the reaction layer toward the outer peripheral wall. In other words, if the stirrer 20 is to generate a liquid flow in such a direction, a preferable arrangement position of the baffle plate 31 corresponding thereto is, of the entire circumference of the outer surface, It is within the range of half of the side close to the outer peripheral wall of the reaction vessel 10.

  The installation position of the baffle plate 31 in the vertical direction may be such that the lower end portion is joined to the vicinity of the gas blowing port as shown in FIGS. 1, 3 and 4, and the installation range is as follows. Any range may be used as long as it extends vertically upward from the lower end as appropriate.

  By disposing the baffle plate 31 at the position and direction within the above-described range, the air bubbles discharged from the gas injection port of the gas injection pipe 30 are caused to flow along the direction from the center of the reaction vessel 10 toward the outer peripheral wall by the liquid flow. While moving, it moves vertically upward by buoyancy. At this time, most of these bubbles collide with the baffle plate 31 in the space above the region B and are cut off, so that the bubble diameter can be sufficiently reduced.

  The material of the baffle plate 31 is not particularly limited, but is preferably formed of an elastic material that is elastically deformed by the liquid flow generated by the stirrer 20. When the baffle plate 31 vibrates due to such elastic deformation, a velocity gradient is generated in the surrounding liquid flow. If bubbles exist, they act as a shear force, so that the bubble diameter can be further reduced. Note that an elastic material capable of imparting such an effect to the baffle plate 31 may be appropriately selected according to a reaction liquid which is a liquid phase. Specifically, a material having corrosion resistance, such as stainless steel or a titanium alloy, or various resins depending on the type of the reaction solution can be used as the elastic material forming the baffle plate 31. Further, it is more preferable that the elastic material forming the baffle plate 31 is made of the same material as the gas blowing pipe 30.

  The shape of the baffle plate 31 may be a plate-like member having a rectangular outer edge, but is not limited to this. Here, as shown in FIG. 3, when the dimension of the baffle plate 31 in the extending direction of the gas blowing tube 30 is the length (L) of the baffle plate 31, the length (L) is not particularly limited. As shown in FIG. 3, for example, the end of the baffle plate 31 on the side of the gas blow-in port of the gas blow-in pipe 30 is located vertically below the gas blow-in port within a range that does not hinder the release of bubbles. Such a length (L) can be used. On the other hand, the end on the opposite side of the baffle plate 31 can also have a length (L) that is, for example, a vertical position substantially equivalent to the installation position of the stirring blade 22 in the reaction vessel 10.

  As shown in FIG. 3, when the width of the baffle plate 31 extending from the gas blowing pipe 30 is set to the width (W) of the baffle plate 31, the width (W) of the baffle plate 31 is as shown in FIG. 3. As shown in the figure, it is preferable that a portion closer to the vertical upper side (a portion closer to the liquid surface of the reaction liquid when the reactor 1 is operated) is larger than a portion near the gas inlet. Bubbles released from the gas blowing port of the gas blowing pipe 30 move toward the liquid surface by buoyancy while being flown by the liquid flow. Will do. Therefore, by making the shape of the baffle plate 31 into such a shape, the contact rate between the bubble rising in the reaction solution due to buoyancy and the baffle plate is increased, and the action of dividing the bubble is more efficiently expressed. be able to.

  In addition, as shown in FIG. 4, the joining mode of the baffle plate 31 to the outer surface of the gas blowing tube 30 is, as illustrated in the joining mode of the gas blowing tube 30 and the baffle plate 31 b, the gas of the gas blowing tube 30. The joint may be made only in the vicinity of the blow-in port, and a part other than this joint may be joined in such a manner that the distance from the gas blow-in tube 30 increases as approaching vertically upward. By adopting such a joining mode, the vibration is easily generated by the liquid flow of the baffle plate 31b, and the effect of dividing the air bubbles by the above-described action relating to the vibration of the baffle plate 31 can be improved.

  Further, the baffle plate 31 is composed of at least one or more baffle plates, and may be composed of a single plate material like the baffle plate 31c shown in FIG. 5, but a plurality of baffle plates like the baffle plate 31d shown in FIG. May be used.

  Further, the baffle plate 31 may be inclined at a predetermined angle instead of being parallel to the extending direction of the gas blowing pipe 30 like the baffle plate 31d shown in FIG. Since the baffle plate 31 is inclined with respect to the gas blow-in tube 30, the ratio of the bubble moving along the baffle plate 31 among the bubbles discharged from the gas blow-in port of the gas blow-in tube 30 is increased. Can be. At this time, since the baffle plate 31 vibrates due to the liquid flow, the effect of separating the bubbles moving along the baffle plate 31 is further improved.

  Further, the baffle plate 31 has a shape such that the end vertically upward, that is, on the side close to the liquid surface of the reaction liquid when the reactor 1 is operated, has a curved surface, like the baffle plate 31d in FIG. Is preferred. By adopting such a shape, a rotational torque is applied to the bubbles moving along the baffle plate 31d, and the action of the bubble separation progresses more efficiently due to a synergistic effect with the liquid flow and the vibration of the baffle plate 31d. . The bending direction of the curved end portion is preferably a direction in which the angle of inclination with respect to the gas blowing pipe 30 is increased by bending. By bending in such a direction, rotation and torque are applied to the bubble in a direction opposing buoyancy, and the effect of dividing the bubble can be further improved.

DESCRIPTION OF SYMBOLS 1 Reaction apparatus 10 Reaction container 20 Stirrer 21 Stirrer shaft 22 Stirrer blade 30 Gas blowing pipe 31, 31a, 31b, 31c, 31d Baffle plate

Claims (5)

A reaction vessel which is a cylindrical liquid phase storage tank;
A stirrer vertically installed at the center of the reaction vessel,
A gas injection pipe having a gas injection port on the lower end side, which is a hollow tubular member vertically suspended at a position closer to the outer peripheral wall than the stirrer in the reaction vessel,
The stirrer is a device that can form a liquid flow from the center of the reaction vessel toward the outer peripheral wall,
A reaction device, wherein a baffle plate extending vertically upward from the vicinity of the gas inlet is provided on the outer surface of the gas inlet tube on the downstream side of the liquid flow.   The reaction device according to claim 1, wherein the baffle plate is formed of an elastic member that is elastically deformed by the liquid flow.   3. The reactor according to claim 1, wherein the baffle plate has a shape in which an extension width from an outer surface of the gas blowing tube is larger on a vertically upper side than a vertically lower side of the baffle plate. 4.   Only part of the baffle plate near the vertically lower end is joined to the outer surface of the gas blowing pipe near the gas blowing port, and the other part of the baffle plate is vertically upward, The reactor according to any one of claims 1 to 3, wherein the reactor is arranged so that the distance from the outer surface of the gas blowing pipe gradually increases.   The reactor according to any one of claims 1 to 4, wherein the baffle plate has a curved surface at a vertically upper end.

Images