CN220861190U - Stirring assembly and stirring device suitable for slurry polymerization solid-liquid two-phase system - Google Patents

Abstract

The application discloses a stirring assembly and a stirring device suitable for a slurry polymerization solid-liquid two-phase system; the stirring assembly is applied to the stirring tank and comprises a stirring shaft and a plurality of paddles which are arranged at intervals along the axial direction of the stirring shaft; the types of the paddles are not identical, so that each paddle utilizes the difference of structures to respectively generate an axial flow field and a radial flow field in the process of driving the paddles to rotate by the stirring shaft. The stirring device comprises the stirring assembly. The application has the beneficial effects that: the axial along the (mixing) shaft sets up a plurality of different paddle of type, utilizes the difference of different paddle self structures for stirring subassembly can produce axial and radial flow field at pivoted in-process, and then can effectually improve the stirring quality to the interior solid-liquid two-phase system of stirred tank.

Description

Stirring assembly and stirring device suitable for slurry polymerization solid-liquid two-phase system

Technical Field

The application relates to the technical field of stirring production, in particular to a stirring assembly and a stirring device suitable for a slurry polymerization solid-liquid two-phase system.

Background

High Density Polyethylene (HDPE) and Ultra High Molecular Weight Polyethylene (UHMWPE) resins achieve an excellent balance between toughness, hardness, environmental stress cracking resistance and processability, and are well suited for the processing of a variety of rigid articles. The main production process comprises the following steps: solution, gas phase, slurry. The slurry method has low reaction pressure, easy control of operation conditions and good product performance, and is a main production method of HDPE and UHMWPE.

Taking high-density polyethylene as an example, in the process of preparing high-density polyethylene by kettle-type slurry polymerization, materials in a stirred polymerization kettle are in a solid-liquid two-phase system, and the suspension state of the generated HDPE solid particles in the kettle directly influences the performance of a final HDPE product. Therefore, it is important to select a stirring paddle (composite paddle) excellent in performance. The existing slurry method stirring type polymerizer is widely applied to a plurality of layers Ping Zhishe stirring paddles; however, in the actual use process, the phenomena of weak area and uneven solid content distribution of a flow field, and further explosion aggregation and agglomeration can occur due to unreasonable blade matching under the working condition of high solid content. Accordingly, there is a need for improvements over existing stirring assemblies.

Disclosure of utility model

It is an object of the present application to provide a stirring assembly that overcomes at least one of the above-mentioned drawbacks of the prior art.

Another object of the present application is to provide a stirring device that can solve at least one of the above-mentioned drawbacks of the related art.

In order to achieve at least one of the above objects, the present application adopts the following technical scheme: a stirring component applicable to a slurry polymerization solid-liquid two-phase system, which is applied to a stirring tank; the stirring device comprises a stirring shaft and a plurality of paddles which are arranged at intervals along the axial direction of the stirring shaft; the types of the paddles are not identical, so that each paddle utilizes the difference of structures to respectively generate an axial flow field and a radial flow field in the process of driving the paddles to rotate by the stirring shaft.

Preferably, the blade type comprises a three-blade back-swept stirring blade, a parabolic disc turbine stirring blade, a three-wide blade rotary stirring blade, an inclined blade disc turbine stirring blade and a straight blade disc turbine stirring blade.

Preferably, the blade at the lowest part of the stirring tank is a three-blade back-swept stirring paddle; the blade positioned at the lower part of the stirring tank is a parabolic disc turbine type stirring blade; the blade positioned in the middle of the stirring tank is a three-wide blade propeller type stirring blade; the blade at the upper part of the stirring tank is an oblique-blade disc turbine type stirring blade; the blades positioned at the top of the stirring tank are inclined blade disc turbine type stirring paddles or straight blade disc turbine type stirring paddles.

Preferably, the plurality of paddles mounted in the axial direction of the stirring shaft are all different in type.

Preferably, the distance between adjacent paddles is equal along the axial direction of the stirring shaft.

Preferably, the distance between two adjacent paddles is L, the diameter of each paddle is D, and the diameter of each stirring groove is D; then l= (0.9 to 1.1) D, d= (0.3 to 0.5) D.

Preferably, the bottom-off height between the lowest blade and the bottom of the stirring tank is L', the bottom-off height between the blade at the lower part of the stirring tank is L ", and the liquid level in the stirring tank is H; then L' = (0.1 to 0.4) d, L "= (0.2 to 0.3) H.

The stirring device suitable for the slurry polymerization solid-liquid two-phase system comprises the stirring assembly, the stirring tank and the driving device; the stirring tank is arranged inside the stirring tank; the driving device is suitable for driving the stirring assembly to stir the solid-liquid two-phase system in the stirring tank.

Preferably, the stirring tank is provided with a plurality of vertical baffles along the circumferential direction on the side wall of the stirring tank.

Preferably, assuming that an extension width of the baffle plate in the radial direction of the stirring tank is B, b= (0.05 to 0.15) D, where D is a diameter of the stirring tank.

Compared with the prior art, the application has the beneficial effects that:

The axial along the (mixing) shaft sets up a plurality of different paddle of type, utilizes the difference of different paddle self structures for stirring subassembly can produce axial and radial flow field at pivoted in-process, and then can effectually improve the stirring quality to the interior solid-liquid two-phase system of stirred tank.

Drawings

FIG. 1 is a schematic view of a part of a stirring device according to the present utility model.

Fig. 2 is a schematic top view of the stirring device according to the present utility model.

Fig. 3 is a schematic view of the structure of each blade type in the present utility model.

Fig. 4 is a schematic structural view of a conventional stirring assembly.

Fig. 5 is a schematic view showing the structure of a first embodiment of the stirring assembly in the present utility model.

FIG. 6 is a schematic view of a second embodiment of a stirring assembly according to the present utility model.

Fig. 7 is a schematic structural view of a third embodiment of a stirring assembly according to the present utility model.

In the figure: stirring assembly 100, blade 110, three-blade swept-back stirring paddle 111, parabolic disk turbine stirring paddle 112, three-wide blade propeller type stirring paddle 113, 45 ° oblique blade disk turbine stirring paddle 114, 75 ° oblique blade disk turbine stirring paddle 115, straight blade disk turbine stirring paddle 116, stirring shaft 120, stirring tank 200, stirring tank 210, and baffle 220.

Detailed Description

The present application will be further described with reference to the following specific embodiments, and it should be noted that, on the premise of no conflict, new embodiments may be formed by any combination of the embodiments or technical features described below.

In the description of the present application, it should be noted that, for the azimuth words such as terms "center", "lateral", "longitudinal", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc., the azimuth and positional relationships are based on the azimuth or positional relationships shown in the drawings, it is merely for convenience of describing the present application and simplifying the description, and it is not to be construed as limiting the specific scope of protection of the present application that the device or element referred to must have a specific azimuth configuration and operation.

It should be noted that the terms "first," "second," and the like in the description and in the claims are used for distinguishing between similar objects and not necessarily for describing a particular sequential or chronological order.

One aspect of the present application provides a stirring assembly 100 suitable for slurry polymerization of a solid-liquid two-phase system, which can be applied to stirring a solid-liquid two-phase system in a stirring tank 210. As shown in fig. 1, 2 and 5 to 7, one embodiment of the present application includes a stirring shaft 120 and a plurality of blades 110 installed at intervals along an axial direction of the stirring shaft 120; the types of the plurality of paddles 110 are not completely identical, so that each paddle 110 utilizes the difference of its own structure to generate an axial flow field and a radial flow field during the rotation of the paddles 110 by the stirring shaft 120.

It will be appreciated that as shown in fig. 4, a conventional stirring assembly 100 is provided to include a stirring shaft 120 and a plurality of blades 110 of the same type and with equal installation intervals, and in general, the blades 110 of the conventional stirring assembly 100 employ a flat blade disc turbine type stirring paddle 116. Therefore, when the stirring assembly 100 stirs the solid-liquid two-phase system in the stirring tank 210, the axial flow field and the radial flow field generated by the blades 110 are relatively uniform in scale because the structures of the blades 110 are the same. However, for the solid-liquid two-phase system, the solid phase is easily accumulated at the bottom of the stirring tank 210 due to gravity, so that the relatively uniform axial flow field and radial flow field do not necessarily have a good mixing effect.

Accordingly, the present application provides for the type of arrangement of the plurality of paddles 110 to be non-identical compared to the conventional stirring assembly 100; namely, the blade 110 with stronger solid-phase mixing capability is arranged below the stirring shaft 120, so as to improve the stirring quality of the stirring assembly 100 on the solid-liquid two-phase system.

In this embodiment, as shown in fig. 3, the types of blades 110 are numerous, and common types of blades 110 include a three-bladed swept-back type stirring blade 111, a parabolic disk turbine type stirring blade 112, a three-bladed rotary blade type stirring blade 113, a diagonal disk turbine type stirring blade, and a straight disk turbine type stirring blade 116. The inclined blade disc turbine type stirring paddles can be further divided into 45-degree inclined blade disc turbine type stirring paddles 114 and 75-degree inclined blade disc turbine type stirring paddles 115 according to different inclined angles of inclined blades.

It should be understood that, in total, six types of paddles 110 are described above, and the types of stirring assemblies 100 that can be formed can be various, and can be specifically expressed by the formula: Where W represents the total number of types of stirring assemblies 100 and N represents the number of paddles 110 included in the stirring assemblies 100. It should be noted that since each blade 110 is affected by its own structure, it cannot be combined at will; that is, the combined effect of the stirring assembly 100 is not as good as that of the conventional stirring assembly 100. Therefore, the combination of the stirring assemblies 100 needs to be limited according to the stirring requirements of the solid-liquid two-phase system.

Specifically, as shown in fig. 5 to 7, since the accumulation of solid particles easily occurs at the bottom of the agitation tank 210, the reaction process is adversely affected; thus, in a paddle-type combination, the lowermost paddles 110 of the stirring assembly 100 may employ three-bladed swept-back paddles 111.

Because the lower region of the agitation tank 210 requires a strong radial flow and dispersion capability when agitation is performed; thus, in performing a paddle-type combination, the paddles 110 positioned in the lower portion of the stirring assembly 100 may employ parabolic disk turbine paddles 112. Parabolic disc turbine agitator blades 112 have a greater radial flow and dispersion capacity and better mass transfer capacity, gas holding capacity than Ping Zhishe disc turbine agitator blades 116.

Because the middle region of the stirring tank 210 requires a better suspension effect of solids when stirring; thus, in performing a paddle combination, the paddles 110 in the middle of the stirring assembly 100 may employ a three-wide blade propeller 113. The tri-wide blade propeller 113 can generate axial flow, is more energy efficient than the flat blade disk turbine propeller 116, has a higher discharge flow rate, and is suitable for solids suspension.

Since the upper region of the agitation tank 210 requires a better circulation ability when agitation is performed; thus, in performing paddle assembly, the paddles 110 located at the upper portion of the stirring assembly 100 may employ a pitched-blade disk turbine type stirring paddle; the inclined blade disc turbine type stirring paddle can generate axial flow, and has good circulation performance and low power consumption.

Since the top region of the agitation tank 210 is likely to generate a supernatant layer when agitation is performed; thus, in order to avoid the presence of a supernatant layer in the top region of the stirred tank 210 when a paddle type combination is performed, either a pitched-blade disk turbine-type stirrer or a flat-blade disk turbine-type stirrer 116 may be employed for the blades 110 at the top of the stirring assembly 100.

It is understood that, in order to ensure the stirring quality of the solid-liquid two-phase system in the stirring tank 210, the stirring tank 210 may be divided into five regions along the axial direction. The five regions are respectively a lowermost region, a lower region, a middle region, an upper region, and a top region. The lowermost region corresponds to a three-bladed swept paddle 100, the lower region corresponds to a parabolic disk turbine paddle 112, the middle region corresponds to a three-bladed rotary paddle 113, the upper region corresponds to a diagonal disk turbine paddle, and the top region corresponds to a diagonal disk turbine paddle or a straight disk turbine paddle 116. It should be understood that the number of blades 110 corresponding to each region may be one or more.

For ease of understanding, the following is an example of the number of paddles 110 corresponding to each region, and specific configurations of the stirring assembly 100 include, but are not limited to, the three types described below.

Structure one: as shown in fig. 5, the stirring assembly 100 includes blades 110, which are a 45 ° oblique-blade disk turbine type stirring blade 114, a three-wide-blade propeller type stirring blade 113, a parabolic disk turbine type stirring blade 112, and a three-blade swept-back type stirring blade 111 in this order from top to bottom along the axial direction of the stirring shaft 120.

And (2) a structure II: as shown in fig. 6, the stirring assembly 100 includes blades 110, which are, in order from top to bottom along the axial direction of the stirring shaft 120, a 75 ° oblique-blade disk turbine type stirring blade 115, a 45 ° oblique-blade disk turbine type stirring blade 114, a three-wide-blade propeller type stirring blade 113, a parabolic disk turbine type stirring blade 112, and a three-blade swept stirring blade 111.

And (3) a structure III: as shown in fig. 7, the stirring assembly 100 includes blades 110, which are a flat-blade disk turbine type stirring blade 116, a 45 ° inclined-blade disk turbine type stirring blade 114, a three-wide-blade propeller type stirring blade 113, a parabolic disk turbine type stirring blade 112 and a three-blade swept-back type stirring blade 111 in this order from top to bottom along the axial direction of the stirring shaft 120.

In this embodiment, in selecting the blade 110, in order to further improve the stirring effect, a plurality of blades 110 having different types may be installed along the axial direction of the stirring shaft 120; that is, the stirring assembly 100 may preferably employ the third structure described above.

It should be noted that the stirring quality of the solid-liquid two-phase system in the stirring tank 210 by the stirring assembly 100 is affected not only by the structure of the blade 110, but also by the mounting structure of the blade 110 and its own size.

In this embodiment, as shown in fig. 1 and 4 to 7, the pitch between adjacent blades 110 is equal in the axial direction of the stirring shaft 120.

Specifically, as shown in fig. 1, a distance between two adjacent paddles 110 may be L, a diameter of the paddles 110 is D, and a diameter of the stirring tank 210 is D; then l= (0.9 to 1.1) D, d= (0.3 to 0.5) D.

Considering that the accumulation of solid phase particles is easily generated at the bottom of the agitation tank 210, the off-bottom height of the lower and lowermost paddles 110 may be defined to ensure that the accumulation of solid phase particles is not or reduced at the bottom of the agitation tank 210. The bottom-off height between the lowest blade 110 and the bottom of the stirring tank 210 may be L', the bottom-off height between the blade 110 at the lower part of the stirring tank 210 may be L ", and the liquid level in the stirring tank 210 may be H; then L' = (0.1 to 0.4) d, L "= (0.2 to 0.3) H.

For ease of understanding, the following description may be given by way of specific parameters.

Let d=480 mm diameter of the stirring tank 210 and h=600 mm height of the liquid surface. The diameter d=144 mm to 240mm of the blade 110 is preferably 160mm. The spacing l=129.6 mm-264 mm between adjacent paddles 110 is preferably 160mm. The bottoming height L' =16 mm to 64mm of the lowermost blade 110 is preferably 32mm. The bottom height L "=120 mm to 180mm of the lower blade 110 is preferably 140mm. That is, the adjacent pitches L ₁＝L₂＝L₃ = 160mm of the first four paddles 110 from top to bottom in the axial direction of the stirring shaft 120, the bottoming height L ₅ = L' = 32mm of the lowest paddle 110, and the bottoming height L ₄ = L "= 140mm of the next-to-last paddle 110.

In another aspect of the present application, there is provided a stirring apparatus suitable for slurry polymerization of a solid-liquid two-phase system, as shown in fig. 1 and 2, wherein one preferred embodiment comprises the stirring assembly 100, the stirring tank 200 and a driving means (not shown) as described above. The specific construction and working principle of the drive means are well known to the person skilled in the art; the stirring tank 200 is internally provided with a stirring tank 210, and a solid-liquid two-phase system is contained in the stirring tank 210; the driving device can drive the stirring assembly 100 to stir the solid-liquid two-phase system in the stirring tank 210.

In this embodiment, as shown in fig. 1 and 2, the stirring tank 200 is provided with a plurality of vertical baffles 220 along the circumferential direction on the side wall of the stirring tank 210. The baffle 220 can prevent the vortex generated by the rotation of the blade 110 from being impacted, so that the mixing effect of the solid and the liquid phases can be further improved.

It will be appreciated that the specific number of baffles 220 may be selected according to the needs of those skilled in the art, for example, as shown in fig. 2, the number of baffles 220 is four, and the baffles are uniformly distributed along the circumferential direction.

In this embodiment, as shown in fig. 1 and 2, if the extending width of the baffle 220 in the radial direction of the stirring tank 210 is B, b= (0.05 to 0.15) D. The parameters mentioned above are carried over, b=24 mm to 72mm when d=480 mm; preferably, b=48 mm.

It can be understood that if the value of B is too small, the blocking effect of the baffle 220 is poor, and thus the mixing of the solid-liquid two-phase system cannot be achieved. If the value of B is too large, the blocking effect of the baffle 220 is large, and thus the generation of the vortex may be affected to some extent. Therefore, the value of B is not too large or too small; in general, b=d/10 is preferred.

The foregoing has outlined the basic principles, features, and advantages of the present application. It will be understood by those skilled in the art that the present application is not limited to the embodiments described above, and that the above embodiments and descriptions are merely illustrative of the principles of the present application, and various changes and modifications may be made therein without departing from the spirit and scope of the application, which is defined by the appended claims. The scope of the application is defined by the appended claims and equivalents thereof.

Claims (8)

1. The stirring assembly is applicable to a slurry polymerization solid-liquid two-phase system and is applied to a stirring tank, and is characterized by comprising a stirring shaft and a plurality of paddles which are arranged at intervals along the axial direction of the stirring shaft; the types of the paddles are not identical, so that each paddle utilizes the difference of structures to respectively generate an axial flow field and a radial flow field in the process of driving the paddles to rotate by the stirring shaft;

The blade type comprises a three-blade back-swept stirring paddle, a parabolic disc turbine stirring paddle, a three-wide blade rotary paddle stirring paddle, an inclined blade disc turbine stirring paddle and a straight blade disc turbine stirring paddle;

The blade at the lowest part of the stirring tank is a three-blade back-swept stirring blade; the blade positioned at the lower part of the stirring tank is a parabolic disc turbine type stirring blade; the blade positioned in the middle of the stirring tank is a three-wide blade propeller type stirring blade; the blade at the upper part of the stirring tank is an oblique-blade disc turbine type stirring blade; the blades positioned at the top of the stirring tank are inclined blade disc turbine type stirring paddles or straight blade disc turbine type stirring paddles.

2. The stirring assembly of claim 1, wherein: the plurality of paddles mounted in the axial direction of the stirring shaft are all different in type.

3. A stirring assembly as set forth in claim 1 or 2, characterized in that: along the axial direction of the stirring shaft, the distance between every two adjacent paddles is equal.

4. A stirring assembly as set forth in claim 3 wherein: the distance between two adjacent paddles is L, the diameter of each paddle is D, and the diameter of each stirring groove is D; then l= (0.9 to 1.1) D, d= (0.3 to 0.5) D.

5. The stirring assembly of claim 4, wherein: the bottom-off height of the blade at the lowest part of the stirring tank and the bottom of the stirring tank is L ', the bottom-off height of the blade at the lower part of the stirring tank is L', and the liquid level in the stirring tank is H; then L' = (0.1 to 0.4) d, L "= (0.2 to 0.3) H.

6. A stirring device suitable for a slurry polymerization solid-liquid two-phase system is characterized in that: comprising a stirring assembly according to any one of claims 1-5, a stirring tank and a driving device; the stirring tank is arranged inside the stirring tank; the driving device is suitable for driving the stirring assembly to stir the solid-liquid two-phase system in the stirring tank.

7. The stirring device of claim 6, wherein: the agitator tank in the lateral wall of stirred tank is provided with a plurality of vertical baffles along the circumferencial direction.

8. The stirring device of claim 7, wherein: assuming that the extending width of the baffle plate along the radial direction of the stirring tank is B, b= (0.05-0.15) D, where D is the diameter of the stirring tank.