A combined paddle stirring device and its application

Abstract

The present invention provides a combined paddle stirring device and its application, the combined paddle stirring device comprises a stirring tank, a stirring shaft is arranged in the stirring tank, at least one stirring blade unit is arranged on the stirring shaft, the stirring blade unit comprises a first nested stirring blade and a second nested stirring blade; the first nested stirring blade comprises two spiral blades and two fixed shafts, the two fixed shafts are arranged staggered with each other and are respectively fixedly connected to the stirring shaft, the two ends of the spiral blade are respectively connected to the two fixed shafts, so that the two spiral blades are arranged in rotational symmetry, and the second nested stirring blade is located between the two fixed shafts and is fixedly connected to the stirring shaft. In the present invention, through the coordinated cooperation of the first nested stirring blade and the second nested stirring blade, the power consumption of slurry mixing is effectively reduced, the stirring efficiency is improved, and it is particularly suitable for the acidification gelation process of high solid content FCC catalyst slurry.

Description

Technical Field

[0001] The invention belongs to stirring equipment in the technical field of petrochemical industry, and relates to a combined paddle stirring device and application thereof. Background Art

[0002] The preparation process of fluid catalytic cracking catalyst usually involves mixing molecular sieve stock solution, kaolin, pseudo-boehmite and acid in a certain proportion to form a slurry with a solid content of about 20-40%, which is usually called the gelling process. The higher the solid content of the slurry, the higher the production efficiency. The subsequent spray drying can also save energy, improve the sphericity of the product, and reduce the generation of fine powder. During the acidification gelling process of the high-solid content FCC catalyst slurry, the material exhibits a strong shear-thinning property, and the apparent viscosity decreases significantly with the increase of the fluid shear rate.

[0003] The stirring paddle is the core component of the stirring device, which determines the flow and mixing efficiency of the material liquid in the stirring device. The blades of the stirring paddle promote the flow of the fluid, and the resulting fluid velocity distribution will inevitably affect the apparent viscosity of the strong shear-thinning catalyst slurry in the stirring device. If the stirring paddle is not designed properly, a dead zone with a zero velocity gradient is likely to appear in the stirring device. The viscosity of the slurry in the dead zone where the stirring paddle cannot reach is extremely high, and the slurry in this area is almost in a static state, resulting in serious uneven mixing of materials in the acidification process in the stirring device, affecting product quality and acidification time.

[0004] In order to strengthen the mixing of non-Newtonian fluids and high-viscosity fluids with shear-thinning characteristics, CN108339445B discloses a combined paddle stirring device, and CN207970760U discloses a combined paddle stirring device. The stirring devices disclosed in this type of patents are a combination of multiple radial flow impellers, or a combination of multiple axial flow impellers, or a combination of multiple axial flows and radial flows. Although this type of combined paddle stirring device can improve the mixing effect of high-viscosity variable-viscosity fluids in the kettle to a certain extent, due to the limited sweep range of each blade during the rotation process, when mixing high-solid content extremely strong shear-thinning slurry, the velocity gradient generated by the blade pushing the fluid is rapidly attenuated, and the energy provided by the blade is rapidly dissipated, resulting in poor circulation mixing of the fluid between the blades. In addition, when stirring high-viscosity variable-viscosity fluids, double-screw propellers, internal and external spiral ribbons, anchor propellers, frame propellers, etc. are often used. Although the mixing effect in the kettle can be improved to a certain extent, the diameter of the propeller is close to the diameter of the stirring device kettle body, and the power consumption is large.

[0005] Therefore, how to improve the mixing efficiency of high-solid content slurry, reduce mixing energy consumption and shorten mixing time is an urgent problem to be solved. Summary of the invention

[0006] In view of the shortcomings of the prior art, the object of the present invention is to provide a combined paddle stirring device and its application. The device increases the shear edge length of the blades and improves the shear rate by combining two stirring blades, reduces the apparent viscosity of high-solid content strongly shear-thinning slurry, shortens the macroscopic mixing time and acidification time of the slurry in the stirring device, reduces power consumption, and effectively improves the stirring efficiency.

[0007] In order to achieve the purpose of the invention, the present invention adopts the following technical solutions:

[0008] In the first aspect, the present invention provides a combined paddle stirring device, the combined paddle stirring device comprises a stirring tank, a stirring shaft is arranged in the stirring tank, at least one stirring blade unit is arranged on the stirring shaft, the stirring blade unit comprises a first nested stirring blade and a second nested stirring blade; the first nested stirring blade comprises two spiral blades and two fixed shafts, the two fixed shafts are staggered and respectively fixedly connected to the stirring shafts, the two ends of the spiral blades are respectively connected to the two fixed shafts, so that the two spiral blades are arranged in rotational symmetry, and the second nested stirring blade is located between the two fixed shafts and fixedly connected to the stirring shaft.

[0009] In the present invention, the coordinated cooperation of the first nested stirring blade and the second nested stirring blade greatly enhances the shear force in the slurry mixing process, effectively reduces the apparent viscosity of the high solid content strong shear thinning slurry, enables each area in the stirring tank to be affected by the driving force of the blade, avoids the phenomenon of dead zones in the mixing process, thereby effectively improving the mixing effect of the materials and reducing the mixing time of the materials.

[0010] As a preferred technical solution of the present invention, a plurality of baffles are evenly distributed on the inner wall of the stirring tank.

[0011] In the present invention, by arranging a plurality of baffles at equal distances on the inner wall of the stirring tank, the shear force at the edge of the stirring tank can be further increased, the flow velocity of the fluid at the edge of the stirring tank can be increased, and the mixing effect can be further enhanced.

[0012] The baffle is arranged parallel to the stirring shaft.

[0013] A plurality of baffles are arranged at equal intervals along the circumference of the stirring tank.

[0014] In the present invention, by arranging the baffle plate parallel to the stirring shaft, the shear force of the slurry during the mixing process can be increased, thereby further improving the mixing efficiency.

[0015] As a preferred technical solution of the present invention, the number of the stirring blade units is at least two, such as 2, 3, 4, 5 or 6, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0016] At least two stirring blade units are arranged at intervals along the axial direction of the stirring shaft.

[0017] In the present invention, the number of stirring blade units can be adjusted according to actual needs. By using at least two stirring blade units, the mixing efficiency of the slurry in the entire stirring tank can be further improved.

[0018] The two adjacent stirring blade units are arranged at an angle of 90°.

[0019] The height of the stirring blade unit is 0.25 to 0.80 times the inner diameter of the stirring tank, for example, 0.25 times, 0.30 times, 0.40 times, 0.50 times, 0.60 times, 0.70 times or 0.80 times, etc., but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0020] In the present invention, by adjusting the height of the stirring blade unit and setting it to 0.25 to 0.80 times the inner diameter of the stirring tank, the mixing effect of the slurry can be further improved and the mixing time of the slurry can be reduced.

[0021] The spacing between two adjacent stirring blade units is 1.00 to 1.25 times the height of the stirring blade unit, for example, 1.00 times, 1.10 times, 1.12 times, 1.14 times, 1.16 times, 1.18 times, 1.20 times, 1.22 times or 1.25 times, etc., but is not limited to the listed values, and other unlisted values ​​within this numerical range are also applicable.

[0022] In the present invention, by adjusting the spacing between the two stirring blade units and setting it to 1.00 to 1.25 times the height of the stirring blade units, the mixing efficiency of the slurry in the stirring tank can be further improved.

[0023] As a preferred technical solution of the present invention, a plurality of first protrusions are arranged on the flow-facing surface of the spiral blade.

[0024] In the present invention, by arranging a plurality of first protrusions on the flow-facing surface of the spiral blade, the shear edge length of the blade can be further increased, the shear force of the slurry during the mixing process can be increased, and the mixing efficiency can be improved.

[0025] A plurality of the first protrusions are arranged at equal intervals along the length direction of the spiral blade.

[0026] The first protrusion has a shape including a triangular prism.

[0027] The height of the first protrusion is 0.005 to 0.025 times the inner diameter of the stirring tank, for example, 0.005 times, 0.010 times, 0.015 times, 0.020 times or 0.025 times, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0028] The width of the first protrusion is 0.005 to 0.025 times the inner diameter of the stirring tank, for example, 0.005 times, 0.010 times, 0.015 times, 0.020 times or 0.025 times, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0029] As a preferred technical solution of the present invention, the diameter of the first nested stirring blade is 0.60 to 0.75 times the inner diameter of the stirring tank, for example, 0.60 times, 0.63 times, 0.66 times, 0.69 times, 0.72 times or 0.75 times, etc., but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0030] The width of the spiral blade is 0.05 to 0.12 times the inner diameter of the stirring tank, for example, 0.05 times, 0.06 times, 0.07 times, 0.08 times, 0.09 times, 0.10 times, 0.11 times or 0.12 times, etc., but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0031] The height of the spiral blade is 0.10 to 0.75 times the inner diameter of the stirring tank, for example, 0.10, 0.20, 0.30, 0.40, 0.50, 0.60, 0.70 or 0.75 times, etc., but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0032] The pitch of the spiral blade is 0.5 to 4.0 times the inner diameter of the stirring tank, for example, 0.5, 1.0, 1.5, 2.0, 2.5, 3.0, 3.5 or 4.0 times, but is not limited to the listed values. Other values ​​not listed within this numerical range are also applicable.

[0033] The span angle of the spiral blade is 30-120°, such as 30°, 50°, 70°, 90°, 100° or 120°, etc., but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0034] As a preferred technical solution of the present invention, the diameter of the fixed shaft is 0.01 to 0.05 times the inner diameter of the stirring tank, for example, 0.01 times, 0.02 times, 0.03 times, 0.04 times or 0.05 times, etc., but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0035] The fixed shaft is provided with a plurality of second protrusions. In the present invention, by providing a plurality of second protrusions on the fixed shaft, the shear edge length of the blade can be further increased, the shear force of the slurry during the mixing process can be increased, and the mixing effect can be further enhanced.

[0036] The shape of the second protrusion includes a cylinder.

[0037] The diameter of the second protrusion is 1 / 2 to 2 / 3 of the diameter of the fixed shaft, such as 1 / 2, 13 / 24, 7 / 12, 5 / 8 or 2 / 3, etc., but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0038] The height of the second protrusion is 2 to 3 times the diameter of the second protrusion, for example 2.0 times, 2.2 times, 2.4 times, 2.6 times, 2.8 times or 3.0 times, etc., but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0039] A plurality of the second protrusions are arranged alternately on the upper and lower sides of the fixed shaft.

[0040] The spacing between two adjacent second protrusions located on the same side of the fixed axis is 2 to 5 times the diameter of the second protrusion, for example 2 times, 3 times, 4 times or 5 times, but is not limited to the listed values, and other unlisted values ​​within this numerical range are also applicable.

[0041] As a preferred technical solution of the present invention, the diameter of the second nested stirring blade is 0.4 to 0.6 times the inner diameter of the stirring tank, for example, 0.40 times, 0.45 times, 0.50 times, 0.55 times or 0.60 times, etc., but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0042] The second nested agitator blade includes at least two bayonet blades.

[0043] The angle between the bayonet-shaped blade and the horizontal plane of the rotation direction is 30~60°, for example 30°, 35°, 40°, 45°, 50°, 55° or 60°, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0044] The width of the bayonet-shaped blade is 0.15 to 0.35 times the diameter of the second nested stirring blade, for example 0.15 times, 0.20 times, 0.25 times, 0.30 times or 0.35 times, etc., but is not limited to the listed values, and other unlisted values ​​within this numerical range are also applicable.

[0045] As a preferred technical solution of the present invention, a plurality of third protrusions are provided on the flow-facing surface of the bayonet-shaped blade.

[0046] In the present invention, by arranging a plurality of third protrusions on the flow-facing surface of the bayonet-shaped blade, the shear edge length of the blade can be further increased, and the shear force on the slurry when flowing through the bayonet-shaped blade can be increased, thereby making the mixing more efficient.

[0047] The third protrusion has a shape including a triangular prism.

[0048] The height of the third protrusion is 0.01 to 0.05 times the diameter of the second nested stirring blade, for example 0.01 times, 0.02 times, 0.03 times, 0.04 times or 0.05 times, etc., but is not limited to the listed values, and other unlisted values ​​within this numerical range are also applicable.

[0049] The width of the third protrusion is 0.01 to 0.05 times the diameter of the second nested stirring blade, for example 0.01 times, 0.02 times, 0.03 times, 0.04 times or 0.05 times, etc., but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0050] In a second aspect, the present invention further provides an application of the combined impeller stirring device as described in the first aspect in the field of petrochemical industry.

[0051] As a preferred technical solution of the present invention, the application includes application in the FCC catalyst gelling process.

[0052] Compared with the prior art, the present invention has the following beneficial effects:

[0053] In the present invention, the shear edge length of the blade is increased and the shear rate is improved through the coordinated cooperation of the first nested stirring blade and the second nested stirring blade, thereby shortening the macroscopic mixing time and acidification time of the slurry in the stirring device, reducing the power consumption of mixing, and effectively improving the stirring efficiency. The invention is particularly suitable for the acidification gelation process of FCC catalyst slurry with high solid content. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] Figure 1 It is a structural schematic diagram of the combined paddle stirring device in Example 1.

[0055] Figure 2It is a stirring blade unit in Example 1.

[0056] Figure 3 3 is a relative position diagram of two adjacent stirring blade units in Example 1.

[0057] Figure 4 This is a front view of the first nested stirring blade in Example 1.

[0058] Figure 5 This is a top view of the first nested stirring blade in Example 1.

[0059] Figure 6 This is a partial view of the triangular prism protrusion on the spiral blade in Example 1.

[0060] Figure 7 It is a front view of the bayonet-shaped blade in Example 1.

[0061] Figure 8 It is a schematic diagram of the structure of the bayonet-shaped blade in Example 1.

[0062] In the figure: 1- stirring tank; 2- stirring shaft; 3- spiral blade; 4- fixed shaft; 5- bayonet blade; 6- baffle; 7- first protrusion; 8- second protrusion; 9- third protrusion.

[0063] a-height of stirring blade unit; b-distance between two adjacent stirring blade units; c-height of spiral blade; d-height of second protrusion; e-distance between adjacent second protrusions; f-diameter of first nested stirring blade; g-width of spiral blade; h-angle of spiral blade; i-height of first protrusion; j-width of first protrusion; k-diameter of second nested stirring blade; l-width of bayonet blade; m-width of third protrusion; n-height of third protrusion. DETAILED DESCRIPTION

[0064] The technical solution of the present invention is further described below by specific implementation methods. It should be understood by those skilled in the art that the embodiments are only to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0065] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by technicians in the technical field to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" in the specification and claims of this application and the above-mentioned figure descriptions and any variations thereof are intended to cover non-exclusive inclusions.

[0066] Example 1

[0067] This embodiment provides a combined paddle stirring device, such as Figures 1 to 8As shown, it includes a stirring tank 1, a stirring shaft 2, four baffles 6 arranged at equal distances along the circumferential direction, a first nested stirring blade composed of two rotationally symmetrical spiral blades 3 and two fixed shafts 4 fixed on the stirring shaft and vertically staggered, a second nested stirring blade composed of two bayonet-shaped blades 5 fixed on the annular structure of the stirring shaft 2, the first nested stirring blade and the second nested stirring blade together constitute a stirring blade unit, and this embodiment consists of two stirring blade units staggered at 90°; and, in this embodiment, three triangular prism-shaped first protrusions are equidistantly arranged on the upstream surface of each spiral blade, five cylindrical second protrusions are equidistantly arranged on the upper and lower sides of each fixed shaft, and three triangular prism-shaped third protrusions are equidistantly arranged on the upstream surface of each bayonet-shaped blade.

[0068] Specifically, the inner diameter of the stirring kettle is 1.2m, the height of the elliptical bottom head is 300mm, and the liquid level height is 1.2m; the height of each stirring blade unit is 350mm, and the spacing between two stirring blade units is 400mm; the width of the baffle is 120mm; the diameter of the first nested stirring blade is 800mm, the width of the spiral blade is 75mm, the height is 230mm, the extension angle is 90°, and the pitch is 1400mm; the height of the first protrusion is 20mm and the width is 20mm; the diameter of the fixed shaft is 30mm, the diameter of the second protrusion is 18mm, the height is 45mm, and the distance between adjacent second protrusions is 140mm; the diameter of the second nested stirring blade is 600mm, the inclination angle is 45°, the width of each bayonet-shaped blade is 125mm, and the width of each third protrusion is 20mm and the height is 20mm.

[0069] Example 2

[0070] The present embodiment provides a combined paddle stirring device, comprising a stirring tank, a stirring shaft, three baffles equidistantly arranged along the circumferential direction, a first nested stirring blade composed of two rotationally symmetrical spiral blades and two fixed shafts fixed on the stirring shaft and vertically staggered, a second nested stirring blade composed of three bayonet-shaped blades fixed on the annular structure of the stirring shaft, the first nested stirring blade and the second nested stirring blade together constitute a stirring blade unit, and the present embodiment consists of a stirring blade unit; and, in the present embodiment, two triangular prism-shaped first protrusions are equidistantly arranged on the frontal surface of each spiral blade, three cylindrical second protrusions are equidistantly arranged on the upper and lower sides of each fixed shaft, and two triangular prism-shaped third protrusions are equidistantly arranged on the frontal surface of each bayonet-shaped blade.

[0071] Specifically, the inner diameter of the stirring kettle is 1.2m, the height of the elliptical bottom head is 300mm, and the liquid level height is 1.2m; the height of the stirring blade unit is 960mm; the width of the baffle is 120mm; the diameter of the first nested stirring blade is 720mm, the width of the spiral blade is 60mm, the height is 880mm, the extension angle is 90°, and the pitch is 3600mm; the height of the first protrusion is 6mm and the width is 6mm; the diameter of the fixed shaft is 20mm, the diameter of the second protrusion is 10mm, the height is 30mm, and the distance between adjacent second protrusions is 50mm; the diameter of the second nested stirring blade is 480mm, the inclination angle is 30°, the width of each bayonet-shaped blade is 150mm, and the width of each third protrusion is 5mm and the height is 5mm.

[0072] Example 3

[0073] The present embodiment provides a combined paddle stirring device, comprising a stirring tank, a stirring shaft, two baffles equidistantly arranged along the circumferential direction, a first nested stirring blade composed of two rotationally symmetrical spiral blades and two fixed shafts fixed on the stirring shaft and staggered, a second nested stirring blade composed of four bayonet-shaped blades fixed on the annular structure of the stirring shaft, the first nested stirring blade and the second nested stirring blade together constitute a stirring blade unit, and the present embodiment consists of three stirring blade units staggered at 90°; and, in the present embodiment, six triangular prism-shaped first protrusions are equidistantly arranged on the frontal surface of each spiral blade, five cylindrical second protrusions are equidistantly arranged on the upper and lower sides of each fixed shaft, and five triangular prism-shaped third protrusions are equidistantly arranged on the frontal surface of each bayonet-shaped blade.

[0074] Specifically, the inner diameter of the stirring kettle is 1.2m, the height of the elliptical bottom head is 300mm, and the liquid level height is 1.2m; the height of each stirring blade unit is 300mm, and the spacing between two stirring blade units is 330mm; the width of the baffle is 120mm; the diameter of the first nested stirring blade is 900mm, the width of the spiral blade is 144mm, the height is 124mm, the extension angle is 120°, and the pitch is 600mm; the height of the first protrusion is 30mm, and the width is 30mm; the diameter of the fixed shaft is 48mm, the diameter of the second protrusion is 32mm, the height is 64mm, and the distance between adjacent second protrusions is 80mm; the diameter of the second nested stirring blade is 720mm, the inclination angle is 60°, the width of each bayonet-shaped blade is 252mm, and the width of each third protrusion is 36mm and the height is 36mm.

[0075] Example 4

[0076] This embodiment provides a stirring device, which is different from Embodiment 1 in that no baffle is provided, and the rest of the structure is the same as that of Embodiment 1.

[0077] Example 5

[0078] This embodiment provides a combined paddle stirring device, which is different from the first embodiment in that the first protrusion is not provided on the spiral blade, and the rest of the structure is the same as that of the first embodiment.

[0079] Example 6

[0080] This embodiment provides a combined paddle stirring device, which differs from Embodiment 1 in that no second protrusion is provided on the fixed shaft, and the rest of the structure is the same as that of Embodiment 1.

[0081] Example 7

[0082] This embodiment provides a combined paddle stirring device, which differs from Embodiment 1 in that no third protrusion is provided on the bayonet-shaped blade, and the rest of the structure is the same as that of Embodiment 1.

[0083] Example 8

[0084] This embodiment provides a stirring device, which is different from Embodiment 1 in that the distance between the two stirring blade units is 500 mm, and the rest of the structure is the same as that of Embodiment 1.

[0085] Example 9

[0086] This embodiment provides a combined paddle stirring device, which is different from Embodiment 1 in that the height of the stirring blade unit is 120 mm, and the rest of the structure is the same as that of Embodiment 1.

[0087] Comparative Example 1

[0088] This comparative example provides a stirring device, which is different from Example 1 in that: a first nested stirring blade is not provided, and the rest of the structure is the same as that of Example 1.

[0089] Comparative Example 2

[0090] This comparative example provides a stirring device, which is different from Example 1 in that no second nested stirring blade is provided, and the rest of the structure is the same as that of Example 1.

[0091] Comparative Example 3

[0092] This comparative example provides a stirring device, including a stirring tank, a stirring shaft, a double-layer downward pressure inclined blade combination paddle and a baffle. Specifically, the inner diameter of the stirring tank is 1.2m, the elliptical bottom head, the head height is 300mm, and the inner wall is closely attached to the wall surface with 4 baffles, 120mm wide; a double-layer downward pressure inclined blade combination paddle is installed on the stirring shaft, each paddle has a diameter of 600mm, a paddle width of 150mm, the number of blades is 2, and the blade inclination angle is 45°; the lower paddle is 350mm high from the bottom, and the spacing between the two layers of paddles is 600mm.

[0093] Comparative Example 4

[0094] This comparative example provides a stirring device, including a stirring tank, a stirring shaft and a double-screw blade. Specifically, the stirring tank has an inner diameter of 1.2m, an elliptical bottom head, a head height of 300mm, and no baffle on the inner wall; a double-screw blade is installed on the stirring shaft, and the blade diameter is 1080mm, the blade width is 150mm, the blade height is 900mm, and the pitch is 600mm.

[0095] Application Example 1-1

[0096] This application example uses the stirring device in Example 1, adds FCC catalyst slurry with a solid content of 30%, and sets the stirring speed to 60 rpm to stir the FCC catalyst into gel.

[0097] Application Example 1-2

[0098] This application example uses the stirring device in Example 1, adds FCC catalyst slurry with a solid content of 38%, and sets the stirring speed to 60 rpm to stir the FCC catalyst into gel.

[0099] Application Examples 2~10

[0100] Application Examples 2 to 10 respectively use the stirring devices in Examples 2 to 10, add FCC catalyst slurry with a solid content of 38%, set the stirring speed to 60 rpm to stir the FCC catalyst into gel.

[0101] Comparative application example 1

[0102] This comparative application example uses the stirring device in comparative example 1, adds FCC catalyst slurry with a solid content of 38%, and sets the stirring speed to 60 rpm to stir the FCC catalyst into gel.

[0103] Comparative Application Example 2

[0104] This comparative application example adopts the stirring device in comparative example 2, adds FCC catalyst slurry with a solid content of 38%, and sets the stirring speed to 60 rpm to stir the FCC catalyst into gel.

[0105] Comparative Application Example 3-1

[0106] This comparative application example adopts the stirring device in comparative example 3, adds FCC catalyst slurry with a solid content of 30%, and sets the stirring speed to 60 rpm to stir the FCC catalyst into gel.

[0107] Comparative Application Example 3-2

[0108] This comparative application example adopts the stirring device in comparative example 3, adds FCC catalyst slurry with a solid content of 38%, and sets the stirring speed to 60 rpm to stir the FCC catalyst into gel.

[0109] Comparative Application Example 4-1

[0110] This comparative application example adopts the stirring device in comparative example 4, adds FCC catalyst slurry with a solid content of 30%, and sets the stirring speed to 60 rpm to stir the FCC catalyst into gel.

[0111] Comparative Application Example 4-2

[0112] This comparative application example adopts the stirring device in comparative example 4, adds FCC catalyst slurry with a solid content of 38%, and sets the stirring speed to 60 rpm to stir the FCC catalyst into gel.

[0113] Performance Testing

[0114] The torque method on the shaft was used to test the power and mixing time of Examples 1 to 9 and Comparative Examples 1 to 4. The test results are shown in Table 1 below:

[0115] Table 1

[0116]

[0117] It can be seen from Application Examples 1 to 3 in Table 1 that in the combined stirring device provided by the present invention, the number of stirring blade units can be adjusted according to actual needs. Through the coordinated cooperation of the first nested stirring blade and the second nested stirring blade, the mixing effect of the high-viscosity variable-viscosity fluid in the kettle can be effectively improved and the mixing time can be greatly reduced.

[0118] From the data of Application Examples 1-2 and Comparative Application Examples 1 and 2 in Table 1, it can be seen that when treating FCC slurry with a solid content of 38%, the combined paddle stirring device provided in Example 1 reduces power consumption by 19.4% and 28.8% respectively, and the macro mixing time is reduced by 60.9% and 70.0% respectively compared with the stirring devices provided in Comparative Examples 1 and 2. This shows that in the present invention, the first nested blade and the second nested blade cooperate together to greatly improve the stirring efficiency.

[0119] From the data of Application Example 1 and Comparative Application Examples 3 and 4 in Table 1, it can be seen that when treating FCC slurry with a solid content of 38%, the combined paddle stirring device provided in Example 1 reduces power consumption by 31.4% and 42.1% respectively, and the macroscopic mixing time is reduced by 55.7% and 23.8% respectively compared with the stirring devices provided in Comparative Examples 3 and 4; when treating FCC slurry with a solid content of 38%, the combined paddle stirring device provided in Example 1 reduces power consumption by 31.8% and 45.6% respectively, and the macroscopic mixing time is reduced by 67.8% and 37.5% respectively compared with the stirring devices provided in Comparative Examples 1 and 2. This shows that the combined paddle stirring device provided in the present invention has higher stirring efficiency than the existing double-layer downward pressure inclined blade combined paddle and double-ribbon paddle, can effectively reduce mixing power consumption, reduce mixing time, and can still maintain a good mixing effect when mixing high-solid content slurry.

[0120] From the data of Application Examples 1-2 and Application Example 4 in Table 1, it can be seen that when treating FCC slurry with a solid content of 38%, the combined paddle stirring device provided in Example 1 has a higher power consumption than the stirring device provided in Example 4, but the mixing time is reduced by 22.4%. This shows that in the present invention, the setting of the baffle can further improve the mixing efficiency.

[0121] It can be seen from the data of Application Examples 1-2 and Application Examples 5-7 in Table 1 that when treating FCC slurry with a solid content of 38%, the combined propeller stirring device provided in Example 1 reduces power consumption by 4.7%, 2.4% and 9.0% respectively, and the mixing time is reduced by 12.8%, 10.9% and 14.8% respectively compared with the stirring device provided in Examples 5-7. This shows that in the present invention, by providing a plurality of protrusions on the propeller blades, the fixed shaft and the bayonet blades, the mixing efficiency of the slurry can be further improved and the energy consumption can be reduced.

[0122] It can be seen from the data of Application Examples 1-2 and Application Examples 8 and 9 in Table 1 that when treating FCC slurry with a solid content of 38%, the combined paddle stirring device provided in Example 1 reduces the mixing time by 23.2% and 26.1% respectively compared with the stirring devices provided in Examples 8 and 9. This shows that in the present invention, by adjusting the height and spacing of the stirring blade units, the time required for slurry mixing can be further reduced and the mixing efficiency can be improved.

[0123] The applicant declares that the above is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention shall fall within the protection scope and disclosure scope of the present invention.

Claims

1. A combined paddle stirring device, characterized in that: The combined paddle stirring device comprises a stirring tank, a stirring shaft is arranged in the stirring tank, at least two stirring blade units are arranged on the stirring shaft, and the stirring blade units comprise a first nested stirring blade and a second nested stirring blade; The first nested stirring blade comprises two spiral blades and two fixed shafts, the two fixed shafts are staggered and respectively fixedly connected to the stirring shafts, the two ends of the spiral blade are respectively connected to the two fixed shafts, so that the two spiral blades are rotationally symmetrically arranged, the second nested stirring blade is located between the two fixed shafts and is fixedly connected to the stirring shafts, the fixed shaft is provided with a plurality of second protrusions, and the plurality of second protrusions are staggered on the upper and lower sides of the fixed shaft; The second nested stirring blade includes at least two bayonet blades; The at least two stirring blade units are spaced apart along the axial direction of the stirring shaft, and two adjacent stirring blade units are staggered at 90°. The height of the stirring blade unit is 0.25 to 0.80 times the inner diameter of the stirring tank, and the spacing between two adjacent stirring blade units is 1.00 to 1.25 times the height of the stirring blade unit. The diameter of the first nested stirring blade is 0.60 to 0.75 times the inner diameter of the stirring tank; A plurality of baffles are evenly distributed on the inner wall of the stirring tank, and the baffles are arranged parallel to the stirring shaft.

2. The combined impeller stirring device according to claim 1, characterized in that: A plurality of baffles are arranged at equal intervals along the circumference of the stirring tank.

3. The combined impeller stirring device according to claim 1, characterized in that: A plurality of first protrusions are arranged on the flow-facing surface of the spiral blade; A plurality of the first protrusions are arranged at equal intervals along the length direction of the spiral blade; The shape of the first protrusion includes a triangular prism; The height of the first protrusion is 0.005 to 0.025 times the inner diameter of the stirring tank; The width of the first protrusion is 0.005 to 0.025 times the inner diameter of the stirring tank.

4. The combined impeller stirring device according to claim 1, characterized in that: The width of the spiral blade is 0.05 to 0.12 times the inner diameter of the stirring tank; The height of the spiral blade is 0.10 to 0.75 times the inner diameter of the stirring tank; The pitch of the spiral blade is 0.5 to 4.0 times the inner diameter of the stirring tank; The span angle of the spiral blade is 30-120°.

5. The combined impeller stirring device according to claim 1, characterized in that: The diameter of the fixed shaft is 0.01 to 0.05 times the inner diameter of the stirring tank; The shape of the second protrusion includes a cylinder; The diameter of the second protrusion is 1 / 2 to 2 / 3 of the diameter of the fixed shaft; The height of the second protrusion is 2 to 3 times the diameter of the second protrusion; The distance between two adjacent second protrusions located on the same side of the fixed axis is 2 to 5 times the diameter of the second protrusion.

6. The combined impeller stirring device according to claim 1, characterized in that: The diameter of the second nested stirring blade is 0.4 to 0.6 times the inner diameter of the stirring tank; The angle between the bayonet blade and the horizontal plane of the rotation direction is 30-60°; The width of the bayonet blade is 0.15 to 0.35 times the diameter of the second nested stirring blade.

7. The combined impeller stirring device according to claim 1, characterized in that: A plurality of third protrusions are arranged on the flow-facing surface of the bayonet-shaped blade; The shape of the third protrusion includes a triangular prism; The height of the third protrusion is 0.01 to 0.05 times the diameter of the second nested stirring blade; The width of the third protrusion is 0.01 to 0.05 times the diameter of the second nested stirring blade.

8. Application of the combined impeller stirring device according to any one of claims 1 to 7 in the field of petrochemical industry.

9. Application of the combined impeller stirring device according to claim 8 in the field of petrochemical industry, characterized in that: The application includes application in the FCC catalyst gelling process.

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