An under-entry type stirring reactor

Abstract

The utility model provides a kind of bottom entry type stirring reactor, the bottom entry type stirring reactor includes shell, bottom entry type stirring device and pressure atomization device;The bottom entry type stirring device includes stirring shaft, stirrer being arranged at the bottom end of stirring shaft and stirring paddle being arranged on the upper portion of stirring shaft;The stirrer is arranged below the outside of shell;The stirring shaft extends into the inside of shell;The pressure atomization device is arranged at the top of shell.The bottom entry type stirring reactor provided by the utility model can avoid raw materials from contacting with stirring shaft and the blade of stirring paddle before being put into liquid surface, so as to reduce product particle size and make product particle size more uniform.

Description

Technical Field

[0001] This utility model relates to the field of chemical equipment technology, and in particular to a bottom-entry stirred reactor. Background Technology

[0002] Liquid-liquid reaction systems are widely used in chemical, energy, environmental, and biochemical fields. Liquid-liquid reactors employ external mechanical stirring devices, resulting in intense liquid-phase turbulence and excellent mixing characteristics and interphase mass transfer rates. The stirring device forces convection and uniformly mixes liquid and gaseous media. The type, size, and rotational speed of the stirrer affect the distribution of stirring power between overall flow and turbulent pulsations. Various types of stirrers are commonly used in industry and laboratories; selecting the appropriate stirrer based on the specific situation can achieve good processing or experimental results. However, existing mechanically driven stirrers, connected to the stirring blades via a drive unit, can cause problems in top-feed reactors. Before being added to the liquid surface, the raw material easily comes into contact with the stirring shaft and blades, leading to the aggregation of large droplets on the surfaces of internal reactor components. In severe cases, this can result in excessively high local raw material concentrations, excessively large product particle sizes, and significant product agglomeration.

[0003] Taking the liquid-liquid process for producing silica as an example, when the feed liquid fed from the top gathers into large droplets on the surface of the internal components of the reactor, the local concentration is easily too high at the moment another raw material liquid is added, resulting in uneven pH value in the local area and excessively fast reaction rate. In a short period of time, a large number of silica crystal nuclei are generated in the local area and agglomerate together, resulting in excessively large product particle size and uneven distribution, which affects product quality.

[0004] CN210613674U discloses a mixing reactor, including a feeding device, a mixing device, a vibrating table, an ultrasonic generator, and an ultrasonic transducer. The feeding device is installed on top of the mixing device and is funnel-shaped with a feed inlet. The feed inlet is equipped with a baffle plate that divides the feed inlet into several individual areas. The mixing device has a mixing chamber, and each individual area is connected to the mixing chamber with an inlet valve. A water inlet pipe with a water valve is located at the top of the mixing chamber. The mixing device is installed on the vibrating table, and a discharge port with a discharge valve is located at the bottom of the mixing device. The vibrating table is equipped with an ultrasonic generator and an ultrasonic transducer, and the ultrasonic generator is connected to the ultrasonic transducer. This reactor utilizes ultrasound to achieve more uniform mixing, but the investment cost is relatively high, limiting the scale of the equipment.

[0005] CN103007870B discloses a nozzle impingement flow rearrangement reactor, mainly comprising a reactor containing a stirrer and horizontally symmetrically arranged nozzles, with the nozzles installed in a tangential feeding manner. An upward-opening immersion impact chamber is provided at the nozzle outlet, and a demister is installed above the immersion impact chamber. The reactor contains 1-5 layers of feed assemblies, each layer consisting of 1-5 pairs, with each layer of feed assemblies arranged axially parallel. Although this reactor can enhance the micro-mixing between fluid particles, localized uneven feed concentrations can still occur, leading to over-reaction and excessively large product particle size.

[0006] Therefore, it is of great significance to provide a reactor that can improve the uniformity of feed-liquid mixing, reduce product particle size, and promote uniform particle size distribution. Utility Model Content

[0007] To address the shortcomings of existing technologies, the purpose of this invention is to provide a bottom-entry stirred reactor. This bottom-entry stirred reactor can prevent raw materials from contacting the stirring shaft and the blades of the stirring paddle before being added to the liquid surface, further avoiding problems such as excessively high local raw material concentration leading to excessively large product particle size and agglomeration.

[0008] To achieve this objective, the present invention adopts the following technical solution:

[0009] This utility model provides a bottom-entry stirred reactor, which includes a shell, a bottom-entry stirring device, and a pressure atomizing device;

[0010] The bottom-entry mixing device includes a mixing shaft, a stirrer disposed at the bottom end of the mixing shaft, and a mixing paddle disposed at the top of the mixing shaft.

[0011] The stirrer is located on the lower exterior of the housing;

[0012] The stirring shaft extends into the housing;

[0013] The pressure atomizing device is located at the top of the housing.

[0014] The bottom-entry stirred reactor provided by this utility model is equipped with a bottom-entry stirring device. The stirrer is set on the lower part of the shell, and the stirring paddle and stirring shaft are both set below the liquid surface inside the reactor. When the pressure atomizing nozzle at the top of the shell sprays the raw material liquid onto the liquid surface, it can avoid the raw material from contacting the stirring shaft and stirring paddle blades before entering the liquid surface. This avoids the raw material from agglomerating into large droplets on the surface of the internal components of the reactor, causing the local raw material liquid concentration to be too high, and further prevents problems such as excessively large particle size or agglomeration of the product.

[0015] Preferably, the pressure atomizing device includes at least one pressure atomizing nozzle, such as one, two or three, preferably one.

[0016] Preferably, the pressure atomizing nozzle is installed at the center of the top of the housing.

[0017] Preferably, the height of the pressure atomizing nozzle accounts for 80-95% of the height of the housing, for example, it can be 80%, 82%, 84%, 86%, 90%, 92%, 94% or 95%, but is not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0018] The present invention preferably controls the height of the pressure atomizing nozzle to be within a specific range of the height of the shell, which can further prevent droplets from falling onto the inner wall of the reactor when the pressure atomizing nozzle sprays the raw material liquid onto the liquid surface, thereby further reducing the particle size of the product.

[0019] Preferably, the impeller blades include at least two layers, for example, two, three or four layers, but are not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0020] The present invention preferably controls the number of blade layers, which can further promote the uniform mixing of raw material liquid and make the particle size of the resulting product more uniform.

[0021] Preferably, the inlet of the pressure atomizing device is connected to a pressurizing pump; a first pneumatic regulating valve is provided between the inlet of the pressure atomizing device and the pressurizing pump.

[0022] Preferably, a feed pipe is provided on one side of the bottom of the housing; a second pneumatic regulating valve is provided at the inlet of the feed pipe.

[0023] Preferably, a discharge pipe is provided on the bottom of the housing opposite to the feed pipe; a ball valve is provided at the outlet of the discharge pipe.

[0024] Preferably, the inner sidewall of the shell is provided with at least two baffles spaced circumferentially, for example, two, three or four, but not limited to the listed values, and other unlisted values ​​within the range are also applicable; the axial direction of the baffles is parallel to the axial direction of the stirring shaft.

[0025] In this invention, the upper end of the baffle plate is positioned below the liquid surface inside the reactor.

[0026] The present invention preferably controls the inner wall of the shell to be provided with at least two baffles spaced circumferentially, which can promote uniform mixing of raw material liquid, thereby making the particle size of the obtained product more uniform.

[0027] Preferably, an online pH detector is provided on the lower side of the housing.

[0028] In this invention, the online pH detector can be associated with the first pneumatic regulating valve and the second pneumatic regulating valve. When the online pH detector detects that the pH value of the liquid in the reactor is not within the set range, the pH value is maintained within the set range by adjusting the feed flow rate of the first and second pneumatic regulating valves.

[0029] Preferably, the height-to-diameter ratio of the shell is ≤1, for example, it can be 1, 0.9, 0.8, 0.7, 0.6 or 0.5, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0030] The bottom-entry stirred reactor provided by this utility model is used for liquid-liquid reactions, and the operation process is as follows:

[0031] Raw material liquid A enters the reactor through the feed pipe at the bottom of the shell. The feed is added until the liquid surface of raw material liquid A is above the agitator. Raw material liquid B is pressurized by a pressure pump and enters the pressure atomizing nozzle. The pressure atomizing nozzle disperses the raw material liquid into small droplets with a particle size of ≤100μm and sprays them onto the liquid surface of raw material liquid A. At the same time, the agitator and baffle promote mixing until the reaction is completed. The resulting reaction slurry flows out through the discharge pipe at the bottom of the shell.

[0032] The above procedure is particularly suitable for the preparation reaction of silica.

[0033] Compared with the prior art, the beneficial effects of this utility model are as follows:

[0034] The bottom-entry stirred reactor provided by this utility model, by setting a bottom-entry stirring device, can avoid the raw materials from contacting the stirring shaft and the blades of the stirring paddle before being put into the liquid surface, and avoid the raw materials from aggregating into large droplets on the surface of the internal components of the reactor, which would cause the local raw material liquid concentration to be too high. Combined with the dispersing effect of the pressure atomization device, the product particle size is further reduced, making the product particle size more uniform. Attached Figure Description

[0035] Figure 1 This is a schematic diagram of the bottom-entry stirred reactor described in Embodiment 1 of this utility model.

[0036] In the diagram: 1-Shell; 2-Pressure atomizing nozzle; 3-Agitator; 4-Infeed pipe; 5-Outlet pipe; 6-Agitator shaft; 7-Agitator paddle; 8-Online pH detector; 9-Pressure pump; 10-First pneumatic regulating valve; 11-Second pneumatic regulating valve; 12-Baffle plate; 13-Ball valve. Detailed Implementation

[0037] The technical solution of this utility model will be further described below with reference to the accompanying drawings and specific embodiments.

[0038] The present invention will now be described in further detail. However, the examples described below are merely simplified examples of the present invention and do not represent or limit the scope of protection of the present invention. The scope of protection of the present invention shall be determined by the claims.

[0039] It should be understood that in the description of this utility model, the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used solely for the convenience of describing this utility model and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, features defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this utility model, unless otherwise stated, "a plurality of" means two or more.

[0040] It should be noted that, in the description of this utility model, unless otherwise explicitly specified and limited, the terms "set," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0041] Those skilled in the art should understand that this utility model necessarily includes the necessary pipelines, conventional valves and general pump equipment for achieving complete process, but the above content is not the main inventive point of this utility model. Those skilled in the art can add layouts based on process flow and equipment structure selection. This utility model does not make any special requirements or specific limitations in this regard.

[0042] Example 1

[0043] This embodiment provides a bottom-entry stirred reactor, the structural schematic diagram of which is shown below. Figure 1 As shown, the bottom-entry stirred reactor includes a shell 1, a bottom-entry stirring device, and a pressure atomizing device. The bottom-entry stirring device includes a stirring shaft 6, a stirrer 3 disposed at the bottom end of the stirring shaft 6, and a stirring paddle 7 disposed at the top of the stirring shaft 6. The stirrer 3 is disposed on the lower exterior of the shell 1, and the stirring shaft 6 extends into the interior of the shell 1. The pressure atomizing device is a pressure atomizing nozzle 2 disposed at the top of the shell 1.

[0044] The impeller blades of the stirring paddle 7 consist of two layers;

[0045] The inner wall of the shell 1 is provided with four baffles 12 spaced circumferentially, and the axial direction of the baffles 12 is parallel to the axial direction of the stirring shaft 6.

[0046] The inlet of the pressure atomizing device is connected to the pressurizing pump 9. A first pneumatic regulating valve 10 is provided between the inlet of the pressure atomizing device and the pressurizing pump 9. A feed pipe 4 is provided on one side of the bottom of the housing 1. A second pneumatic regulating valve 11 is provided at the inlet of the feed pipe 4. A discharge pipe 5 is provided on the bottom side of the housing 1 opposite to the feed pipe 4. A ball valve 13 is provided at the outlet of the discharge pipe 5. An online pH detector 8 is provided on one side of the lower part of the housing 1.

[0047] When the online pH detector 8 detects that the pH value of the liquid in the reactor is not within the set range, the pH value is maintained within the set range by adjusting the feed flow rate of the first pneumatic regulating valve 10 and the second pneumatic regulating valve 11.

[0048] The height of the pressure atomizing nozzle 2 is 90% of the height of the housing 1, and the height-to-diameter ratio of the housing 1 is 1.

[0049] Example 2

[0050] This embodiment provides a bottom-entry stirred reactor, which includes a shell, a bottom-entry stirring device, and a pressure atomizing device. The bottom-entry stirring device includes a stirring shaft, a stirrer disposed at the bottom end of the stirring shaft, and a stirring paddle disposed at the top of the stirring shaft. The stirrer is disposed on the lower exterior of the shell, and the stirring shaft extends into the interior of the shell. The pressure atomizing device is a pressure atomizing nozzle disposed at the top of the shell.

[0051] The impeller blades consist of 3 layers;

[0052] The inner wall of the shell is provided with two baffles spaced circumferentially, and the axial direction of the baffles is parallel to the axial direction of the stirring shaft.

[0053] The inlet of the pressure atomizing device is connected to a pressurizing pump. A first pneumatic regulating valve is provided between the inlet of the pressure atomizing device and the pressurizing pump. A feed pipe is provided on one side of the bottom of the housing. A second pneumatic regulating valve is provided at the inlet of the feed pipe. A discharge pipe is provided on the bottom side of the housing opposite to the feed pipe. A ball valve is provided at the outlet of the discharge pipe. An online pH detector is provided on one side of the lower part of the housing.

[0054] When the online pH detector detects that the pH value of the feed liquid in the reactor is not within the set range, the feed flow rate of the first pneumatic regulating valve and the second pneumatic regulating valve are adjusted to maintain the pH value within the set range.

[0055] The height of the pressure atomizing nozzle accounts for 80% of the height of the housing, and the height-to-diameter ratio of the housing is 0.8.

[0056] Example 3

[0057] This embodiment provides a bottom-entry stirred reactor, which includes a shell and a bottom-entry stirring device. The bottom-entry stirring device includes a stirring shaft, a stirrer disposed at the bottom end of the stirring shaft, and a stirring paddle disposed at the top of the stirring shaft. The stirrer is disposed on the lower exterior of the shell, and the stirring shaft extends into the interior of the shell. The pressure atomizing device is a pressure atomizing nozzle disposed at the top of the shell.

[0058] The impeller blades consist of two layers;

[0059] The inner wall of the shell is provided with three baffles spaced circumferentially, and the axial direction of the baffles is parallel to the axial direction of the stirring shaft.

[0060] The inlet of the pressure atomizing device is connected to a pressurizing pump. A first pneumatic regulating valve is provided between the inlet of the pressure atomizing device and the pressurizing pump. A feed pipe is provided on one side of the bottom of the housing. A second pneumatic regulating valve is provided at the inlet of the feed pipe. A discharge pipe is provided on the bottom side of the housing opposite to the feed pipe. A ball valve is provided at the outlet of the discharge pipe. An online pH detector is provided on one side of the lower part of the housing.

[0061] When the online pH detector detects that the pH value of the feed liquid in the reactor is not within the set range, the feed flow rate of the first pneumatic regulating valve and the second pneumatic regulating valve are adjusted to maintain the pH value within the set range.

[0062] The height of the pressure atomizing nozzle accounts for 95% of the height of the housing, and the height-to-diameter ratio of the housing is 0.9.

[0063] Example 4

[0064] This embodiment provides a bottom-entry stirred reactor, which differs from Embodiment 1 only in that the height of the pressure atomizing nozzle accounts for 70% of the shell height.

[0065] Example 5

[0066] This embodiment provides a bottom-entry stirred reactor, which differs from Embodiment 1 only in that the height of the pressure atomizing nozzle accounts for 98% of the shell height.

[0067] The bottom-entry stirred reactors provided in Examples 1-5 are used in the following process for the production of silica:

[0068] A 20% ammonium fluorosilicate solution (A) is used as raw material A, with a flow rate of 1.5 m / s. It enters the reactor through the feed pipe at the bottom of the shell and is added until the surface of raw material A is above the agitator. A 20% ammonia solution (B) is used as raw material B, with a flow rate of 0.7 m / s. It is pressurized by a pressurizing pump and enters the pressure atomizing nozzle, which sprays it onto the surface of raw material A. At the same time, the agitator and baffles promote mixing. The reaction is carried out for 0.5 h at a temperature of 25°C and a pressure of atmospheric pressure until the reaction is completed. The resulting reaction slurry flows out through the discharge pipe at the bottom of the shell.

[0069] Using the reactors of Examples 1-5, under the same raw material liquid and reaction conditions, the average particle size of the prepared silica is shown in Table 1.

[0070] Table 1

[0071] Example 1 61.7 Example 2 58.5 Example 3 65.6 Example 4 96.5 Example 5 98.8

[0072] The following points can be observed from the data in Examples 1-5:

[0073] (1) In the preparation process of Examples 1-3, the average particle size of the obtained silica product reached below 65.6 nm and the particle size distribution was relatively uniform.

[0074] (2) Compared with Examples 4-5, the height of the pressure atomizing nozzle in Example 1 accounts for 90% of the height of the housing, compared with 70% and 98% in Examples 4-5 respectively. The average particle size in Example 1 is significantly lower than that in Examples 4-5. Therefore, it can be seen that the present invention prefers the proportion of the height of the pressure atomizing nozzle to the height of the housing, which can further reduce the particle size of the product.

[0075] In summary, the bottom-entry stirred reactor provided by this utility model can prevent the raw materials from contacting the stirring shaft and the blades of the stirring paddle before they are added to the liquid surface, thereby reducing the product particle size and making the product particle size more uniform.

[0076] The applicant declares that the above description is only a specific embodiment of the present utility model, but the protection scope of the present utility model is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present utility model fall within the protection and disclosure scope of the present utility model.

Claims

1. A bottom-entry stirred reactor, characterized in that, The bottom-entry stirred reactor includes a shell, a bottom-entry stirring device, and a pressure atomizing device; The bottom-entry mixing device includes a mixing shaft, a stirrer disposed at the bottom end of the mixing shaft, and a mixing paddle disposed at the top of the mixing shaft. The stirrer is located on the lower exterior of the housing; The stirring shaft extends into the housing; The pressure atomizing device is located at the top of the housing.

2. The bottom-entry stirred reactor according to claim 1, characterized in that, The pressure atomizing device includes at least one pressure atomizing nozzle.

3. The bottom-entry stirred reactor according to claim 2, characterized in that, The height of the pressure atomizing nozzle accounts for 80-95% of the height of the housing.

4. The bottom-entry stirred reactor according to claim 1, characterized in that, The impeller blades consist of at least two layers.

5. The bottom-entry stirred reactor according to claim 1, characterized in that, The inlet of the pressure atomizing device is connected to a pressure pump; A first pneumatic regulating valve is provided between the inlet of the pressure atomizing device and the pressurizing pump.

6. The bottom-entry stirred reactor according to claim 1, characterized in that, A feed pipe is provided on one side of the bottom of the housing; The feed pipe inlet is equipped with a second pneumatic regulating valve.

7. The bottom-entry stirred reactor according to claim 6, characterized in that, A discharge pipe is provided on the bottom of the housing on the side opposite to the feed pipe; A ball valve is installed at the outlet of the discharge pipe.

8. The bottom-entry stirred reactor according to claim 1, characterized in that, The inner wall of the shell is provided with at least two baffles spaced circumferentially. The axial direction of the baffle plate is parallel to the axial direction of the stirring shaft.

9. The bottom-entry stirred reactor according to claim 1, characterized in that, An online pH detector is provided on one side of the lower part of the housing.

10. The bottom-entry stirred reactor according to claim 1, characterized in that, The height-to-diameter ratio of the shell is ≤1.

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