Spray drying device for strengthening interphase heat transfer

Abstract

The invention relates to the field of spray drying devices, in particular to a spray drying device for strengthening interphase heat transfer, which comprises a spray drying tower body, an upper section tower body, a middle section tower body, a lower section tower body, a flue gas distribution plate A, a flue gas distribution plate B and a spray gun, an upper section tower body with a conical structure is welded at the upper end of the middle section tower body; a lower section tower body with a conical structure is welded at the lower end of the middle section tower body; the middle-section tower body adopts a cylindrical structure; the invention provides an innovative flue gas distribution plate trepanning form and a spray gun arrangement form, and the trepanning form of the flue gas distribution plate is adjusted, so that the trepanning circle center position of the large hole in the flue gas distribution plate is overlapped with the axis of the spray gun, and high-temperature flue gas is concentrated near the spray nozzle after passing through the distribution plate and can completely cover liquid drops sprayed by the spray nozzle; therefore, under the condition of ensuring reasonable pressure drop in the tower, the heat exchange efficiency between the high-temperature flue gas and the cold slurry is greatly improved, and meanwhile, large-area adhesion of the slurry in a wet particle state is avoided.

Description

Technical Field

[0001] The invention relates to the field of spray drying devices, in particular to a spray drying device for enhancing interphase heat transfer. Background Art

[0002] In industrial production, fluid catalytic cracking process is an important means of secondary processing of crude oil, among which microsphere catalyst is the core of catalytic cracking technology, and spray drying technology is the main technology for drying and granulating catalytic cracking catalyst.

[0003] The main device of spray drying technology is the spray drying tower, which usually involves three stages: atomization of raw material liquid, contact and mixing of droplets with high-temperature drying medium, and separation of dried products and waste gas. The stage that has the greatest impact on product quality is the contact and mixing of droplets with drying medium, that is, the drying behavior of droplets. Studies have shown that the drying behavior of droplets is affected by operating parameters. For example, when the nozzles are arranged in a cross form or a centripetal concentrated form, the distance between adjacent droplets is shortened, and the possibility of contact between droplets increases, which may cause the droplets to stick together. This sticking phenomenon will not only cause the particle size of the catalyst product to increase abnormally, but also may damage the catalyst product. The ideal spherical structure is destroyed, which in turn has an adverse effect on the subsequent catalytic cracking reaction, reducing the reaction efficiency and the activity of the catalyst; the poor contact and uneven mixing of the droplets with the high-temperature flue gas will lead to a slower drying rate and a decrease in drying efficiency, while increasing the probability of collision between wet particles and dry particles, causing agglomeration between particles, affecting the particle size distribution of the catalyst product. Therefore, the hole form of the flue gas distribution plate and the arrangement of the spray gun in the spray drying tower are modified. While considering the difficulty of structural modification and the cost of modification, the drying efficiency is improved and the product quality is improved. This has great engineering and technical value and socio-economic significance for the catalyst granulation industry.

[0004] Therefore, in order to address the key issues faced by spray drying towers in current industrial production, such as low drying efficiency and particle size distribution that cannot meet specific process requirements, a spray drying device that enhances interphase heat transfer can be designed. Summary of the invention

[0005] In order to overcome the key problems faced by spray drying towers in current industrial production, such as low drying efficiency and particle size distribution that cannot meet specific process requirements.

[0006] The technical scheme of the present invention is: a spray drying device for strengthening interphase heat transfer, comprising a spray drying tower body, an upper tower body, a middle tower body, a lower tower body, an air inlet, an air outlet, a smoke distribution plate A, a smoke distribution plate B, and a spray gun; the spray drying tower body comprises an upper tower body, a middle tower body and a lower tower body; the upper end of the middle tower body is welded with an upper tower body with a conical structure; the lower end of the middle tower body is welded with a lower tower body with a conical structure; the middle tower body adopts Cylindrical structure; a cylindrical air inlet is fixedly connected to the outer side of the side wall of the upper tower body; a 90° bent pipe outlet is fixedly connected to the lower end of the outlet of the lower tower body; a smoke distribution plate A and a smoke distribution plate B are respectively installed on the inner side of the upper tower body; the smoke distribution plate A is located at the upper end of the smoke distribution plate B; the smoke distribution plate A and the smoke distribution plate B have the same opening rate and are installed at a lower position than the air inlet; a spray gun is installed on the inner side of the upper tower body; the spray gun passes through the smoke distribution plate A and the smoke distribution plate B.

[0007] Preferably, a flue gas distribution plate A and a flue gas distribution plate B are arranged in the cone area of ​​the upper tower body of the spray drying tower, which are used to rectify the high-temperature flue gas entering tangentially into a vertical downward flow, so as to avoid the flue gas being concentrated near the wall surface to cause heat loss. The number of large holes on the flue gas distribution plate A and the flue gas distribution plate B is the same as that of the spray gun, and the opening position of the large hole is determined by the spray gun, that is, the opening center coincides with the axis of the spray gun, and the opening area of ​​the large hole is slightly larger than the maximum area of ​​the circle formed by the droplets sprayed from the spray gun, so that the high-temperature flue gas will be concentrated in the area near the nozzle after passing through the flue gas distribution plate, so as to ensure that the cold slurry can quickly exchange sufficient heat with the high-temperature flue gas once it is sprayed. The spray gun adopts a vertical downward arrangement method to eliminate the adverse effect of the cross-arrangement of the nozzles on the product particle size;

[0008] Specific research method: Under simulation conditions, the physical model was drawn using Solidworks software according to the components of the spray drying tower body and the sizes of the flue gas distribution plates A, B and spray guns. ICEM software was then used for meshing, and the meshes of the smaller spray guns and flue gas distribution plates A and B were encrypted to ensure the accuracy of the numerical simulation. Appropriate material properties were set through literature research and operating parameters that could meet industrial needs were selected. Numerical simulation was used to obtain parameters such as the drying rate and particle size distribution under theoretical conditions.

[0009] Preferably, the diameter of the air inlet is 1300 mm; the diameter of the air outlet is 1800 mm; and the angle between the air inlet and the air outlet is 90°.

[0010] Preferably, the spray guns are arranged vertically; there are 8 spray guns; the spray guns are arranged on a circle 3500 mm away from the center; the spray guns are distributed equidistantly in a ring; the diameter of the spray gun is 150 mm; the spray gun uses a pressure nozzle; and the spray gun extends into the tower by 300 mm.

[0011] Preferably, the thickness of the smoke distribution plate A and the smoke distribution plate B are both 200 mm; the distance between the smoke distribution plate A and the smoke distribution plate B is 1000 mm.

[0012] Preferably, large holes are provided on the outer surfaces of the smoke distribution plates A and B; the number of large holes in the smoke distribution plates A and B is the same as the number of spray guns; the positions of the large holes in the smoke distribution plates A and B coincide with the center position of the spray guns.

[0013] Preferably, the diameter of the smoke distribution plate A is 9345mm; the diameter of the large hole of the smoke distribution plate A is 1500mm; the diameter of the smoke distribution plate B is 10500mm; the diameter of the large hole of the smoke distribution plate B is 1688mm; except for the 16 large holes that coincide with the spray gun positions, the small holes with a diameter of 120mm are evenly distributed at other positions of the smoke distribution plate A and the smoke distribution plate B.

[0014] Beneficial effects of the present invention:

[0015] The present invention provides an innovative flue gas distribution plate opening form and spray gun arrangement form, which is intended to simultaneously improve the drying efficiency and the quality of catalyst particles, thereby effectively solving the key problems faced by spray drying towers in current industrial production, such as low drying efficiency and particle size distribution that cannot meet specific process requirements;

[0016] By adjusting the opening form of the flue gas distribution plate, the opening center position of the large hole on the flue gas distribution plate coincides with the axis of the spray gun, the opening area is slightly larger than the maximum area of ​​the circle formed by the droplets sprayed from the spray gun, and small holes are evenly arranged at the remaining positions, so that the high-temperature flue gas is concentrated near the nozzle after passing through the distribution plate and can completely cover the droplets sprayed from the nozzle, thereby greatly improving the heat exchange efficiency between the high-temperature flue gas and the cold slurry while ensuring a reasonable pressure drop in the tower. At the same time, the vertical arrangement of the spray gun reduces the cross-influence between the spray guns, avoiding large-area adhesion of the slurry in the wet particle state, which affects the product particle size. The present invention has a simple structure and is easy to implement at the operational level. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 Shown is a schematic diagram of the three-dimensional structure of the spray drying tower of the spray drying device of the present invention;

[0018] Figure 2 Shown is a schematic diagram of the vertical arrangement of the spray guns and the opening of the smoke distribution plate of the spray drying device of the present invention;

[0019] Figure 3 The top view of the opening form and the arrangement form of the spray guns of the smoke distribution plate A of the spray drying device of the present invention is shown;

[0020] Figure 4The top view of the opening form and the arrangement form of the spray guns of the smoke distribution plate B of the spray drying device of the present invention is shown;

[0021] Figure 5 Shown is a schematic diagram of the change in particle size of a single droplet when the spray drying device of the present invention is drying;

[0022] Figure 6 The droplet particle size distribution curve after drying of the spray drying device of the present invention is shown.

[0023] Explanation of the accompanying drawings: 1. spray drying tower body; 2. upper tower body; 3. middle tower body; 4. lower tower body; 5. air inlet; 6. air outlet; 7. flue gas distribution plate A; 8. flue gas distribution plate B; 9. spray gun; 10. large hole; 11. small hole. DETAILED DESCRIPTION

[0024] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0025] See also Figure 1-6 The present invention provides an embodiment: a spray drying device for strengthening interphase heat transfer, comprising a spray drying tower body 1, an upper tower body 2, a middle tower body 3, a lower tower body 4, an air inlet 5, an air outlet 6, a smoke distribution plate A7, a smoke distribution plate B8, and a spray gun 9; the spray drying tower body 1 comprises an upper tower body 2, a middle tower body 3 and a lower tower body 4; the upper end of the middle tower body 3 is welded with an upper tower body 2 with a conical structure; the lower end of the middle tower body 3 is welded with a lower tower body 4 with a conical structure; the middle tower body 3 adopts a cylindrical structure; the outer side of the side wall of the upper tower body 2 is fixedly connected with a conical structure. A cylindrical air inlet 5; a 90° bent pipe air outlet 6 is fixedly connected to the lower end of the outlet of the lower tower body 4; a smoke distribution plate A7 and a smoke distribution plate B8 are respectively installed on the inner side of the upper tower body 2; the smoke distribution plate A7 is located at the upper end of the smoke distribution plate B8; the smoke distribution plate A7 and the smoke distribution plate B8 have the same opening rate and are installed at a lower position than the air inlet 5; a spray gun 9 is installed on the inner side of the upper tower body 2; the spray gun 9 penetrates the smoke distribution plate A7 and the smoke distribution plate B8; the diameter of the air inlet 5 is 1300 mm; the diameter of the air outlet 6 is 1800 mm; and there is a 90° angle between the air inlet 5 and the air outlet 6.

[0026] See also Figure 2 In this embodiment, the spray guns 9 are arranged vertically; there are 8 spray guns 9; the spray guns 9 are arranged on a circle 3500 mm away from the center; the spray guns 9 are distributed equidistantly in a ring; the diameter of the spray guns 9 is 150 mm; the spray guns 9 use a pressure nozzle; the spray guns 9 extend into the tower by 300 mm.

[0027] See also Figure 3 , 4In this embodiment, the thickness of the smoke distribution plate A7 and the smoke distribution plate B8 are both 200mm; the spacing between the smoke distribution plate A7 and the smoke distribution plate B8 is 1000mm; large holes 10 are opened on the outer surfaces of the smoke distribution plate A7 and the smoke distribution plate B8; the number of large holes 10 of the smoke distribution plate A7 and the smoke distribution plate B8 is the same as the number of spray guns 9; the positions of the large holes 10 of the smoke distribution plate A7 and the smoke distribution plate B8 coincide with the center position of the spray gun 9; the diameter of the smoke distribution plate A7 is 9345mm; the diameter of the large holes 10 of the smoke distribution plate A7 is 1500mm; the diameter of the smoke distribution plate B8 is 10500mm; the diameter of the large holes 10 of the smoke distribution plate B8 is 1688mm; except for the 16 large holes 10 that coincide with the positions of the spray guns 9, the smoke distribution plates A7 and the smoke distribution plates B8 have small holes 11 with a diameter of 120mm evenly distributed in other positions.

[0028] During operation, a flue gas distribution plate A7 and a flue gas distribution plate B8 are arranged in the cone area of ​​the upper tower body 2 of the spray drying tower body 1, which are used to rectify the high-temperature flue gas entering tangentially into a vertical downward flow, so as to avoid the flue gas being concentrated near the wall surface to cause heat loss. The number of large holes 10 on the flue gas distribution plate A7 and the flue gas distribution plate B8 is the same as that of the spray gun 9, and the opening position of the large hole 10 is determined by the spray gun 9, that is, the opening circle center coincides with the axis of the spray gun 9, and the opening area of ​​the large hole 10 is slightly larger than the maximum area of ​​the circle formed by the droplets sprayed from the spray gun 9, so that the high-temperature flue gas will be concentrated in the area near the nozzle after passing through the flue gas distribution plate, so as to ensure that the cold slurry can quickly exchange sufficient heat with the high-temperature flue gas once it is sprayed. The spray gun 9 adopts a vertical downward arrangement method to eliminate the adverse effects of the cross arrangement of the nozzles on the product particle size;

[0029] Specific research method: Under simulation conditions, the physical model was drawn using Solidworks software according to the components of the spray drying tower body 1 and the sizes of the flue gas distribution plate A7, flue gas distribution plate B8 and spray gun 9. Then, the ICEM software was used for meshing, and the mesh of the smaller spray gun 9 and flue gas distribution plate A7, flue gas distribution plate B8 areas was encrypted to ensure the accuracy of the numerical simulation. Through literature research, appropriate material properties were set and operating parameters that could meet industrial needs were selected. Numerical simulation was used to obtain parameters such as the drying rate and particle size distribution under theoretical conditions.

Claims

1. A spray drying device for enhancing interphase heat transfer, comprising a spray drying tower body (1); characterized in that: The spray drying tower also comprises an upper tower body (2), a middle tower body (3), a lower tower body (4), an air inlet (5), an air outlet (6), a smoke distribution plate A (7), a smoke distribution plate B (8), and a spray gun (9); the spray drying tower body (1) comprises an upper tower body (2), a middle tower body (3), and a lower tower body (4); the upper end of the middle tower body (3) is welded with an upper tower body (2) with a conical structure; the lower end of the middle tower body (3) is welded with a lower tower body (4) with a conical structure; the middle tower body (3) adopts a cylindrical structure; the outer side wall of the upper tower body (2) is A cylindrical air inlet (5) is fixedly connected to the side; a 90° bent pipe air outlet (6) is fixedly connected to the lower end of the outlet of the lower tower body (4); a smoke distribution plate A (7) and a smoke distribution plate B (8) are respectively installed on the inner side of the upper tower body (2); the smoke distribution plate A (7) is located at the upper end of the smoke distribution plate B (8); the smoke distribution plate A (7) and the smoke distribution plate B (8) have the same opening rate and are installed at a position lower than the air inlet (5); a spray gun (9) is installed on the inner side of the upper tower body (2); the spray gun (9) penetrates the smoke distribution plate A (7) and the smoke distribution plate B (8).

2. The spray drying device for enhancing interphase heat transfer according to claim 1, characterized in that: The diameter of the air inlet (5) is 1300 mm; the diameter of the air outlet (6) is 1800 mm; and the air inlet (5) and the air outlet (6) form an angle of 90°.

3. The spray drying device for enhancing interphase heat transfer according to claim 1, characterized in that: The spray guns (9) are arranged vertically; there are 8 spray guns (9); the spray guns (9) are arranged on a circumference 3500 mm away from the center; the spray guns (9) are distributed in a circular manner with equal spacing; the diameter of the spray gun (9) is 150 mm; the spray gun (9) adopts a pressure nozzle; the spray gun (9) extends into the tower by 300 mm.

4. The spray drying device for enhancing interphase heat transfer according to claim 1, characterized in that: The thickness of the smoke distribution plate A (7) and the smoke distribution plate B (8) are both 200 mm; the distance between the smoke distribution plate A (7) and the smoke distribution plate B (8) is 1000 mm.

5. The spray drying device for enhancing interphase heat transfer according to claim 1, characterized in that: The outer surfaces of the smoke distribution plate A (7) and the smoke distribution plate B (8) are both provided with large holes (10); the number of the large holes (10) of the smoke distribution plate A (7) and the smoke distribution plate B (8) is the same as the number of the spray guns (9); the positions of the large holes (10) of the smoke distribution plate A (7) and the smoke distribution plate B (8) coincide with the center position of the spray gun (9).

6. The spray drying device for enhancing interphase heat transfer according to claim 1, characterized in that: The diameter of the smoke distribution plate A (7) is 9345 mm; the diameter of the large hole (10) of the smoke distribution plate A (7) is 1500 mm; the diameter of the smoke distribution plate B (8) is 10500 mm; and the diameter of the large hole (10) of the smoke distribution plate B (8) is 1688 mm.

7. The spray drying device for enhancing interphase heat transfer according to claim 1, characterized in that: The smoke distribution plate A (7) and the smoke distribution plate B (8) have small holes (11) with a diameter of 120 mm evenly distributed at other positions, except for the 16 large holes (10) that coincide with the positions of the spray guns (9).

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