Double distribution component self-cleaning fluidized bed heat exchanger

Abstract

The present invention provides a self-cleaning fluidized bed heat exchanger with dual distribution components, characterized in that the self-cleaning fluidized bed heat exchanger with dual distribution components includes a lower tube box 1, heat exchanger tubes 2, an upper tube box 3, a liquid-solid separation box 4, a downcomer 5, a solid particle tank 6, a liquid storage tank 7, and a liquid circulation pump 8. The lower tube box 1 includes a support ring 9, a baffle 10, a diffuser 11, and a three-pronged support 12. The support ring 9 is fixedly installed in the lower tube box 1, the baffle 10 is installed on the support ring 9, the three-pronged support 12 is installed above the support ring 9, and the diffuser 11 is connected to the three-pronged support 12. Solid particles enter the solid particle tank 6 through the downcomer 5 and then, under the action of the liquid circulation pump 8, enter the lower tube box 1 together with the liquid flowing from the liquid storage tank 7. The technical solution of the self-cleaning fluidized bed heat exchanger with dual distribution components can effectively solve the above-mentioned problems and can be used to extend the operating cycle of the top heat exchanger of the atmospheric and vacuum device.

Description

Technical Field

[0001] The present invention belongs to the field of chemical industry, specifically, to the field of long-cycle operation of chemical heat exchange equipment, and relates to a self-cleaning fluidized bed heat exchanger with double distributed components, which is widely used to solve the long-cycle operation problem of shell and tube heat exchangers in which adhesion and scaling are prone to occur in the tube side of the circulating liquid phase. Background Art

[0002] Heat exchangers are widely used in the petrochemical industry. However, after long-term use, scaling will inevitably occur inside the heat exchanger, which greatly increases the heat transfer resistance inside the heat exchanger, greatly reduces the heat transfer efficiency of the heat exchanger, and seriously affects the normal use of the heat exchanger.

[0003] The development of a fluidized bed heat exchanger with self-cleaning and descaling capabilities can effectively reduce the thermal resistance inside the heat exchanger, thereby preventing the heat exchange efficiency of the heat exchanger from decreasing, and further extending the service life of the heat exchanger equipment within a cycle, which has significant economic benefits.

[0004] Patent US 005676201A discloses an external circulation fluidized bed heat exchanger. However, the fluidized bed heat exchanger fails to fully consider the uniform distribution of solid particles, and thus its ability to maintain high heat transfer efficiency over a long period of use is weak.

[0005] Patent CN 202709856U discloses a horizontal liquid-solid circulating fluidized bed heat exchanger using a Kenics static mixer. However, the circulation and distribution effects of the circulating fluidized bed heat exchanger are poor. At the same time, its Kenics static mixer can only be used in horizontal heat exchangers and is not widely used.

[0006] Patent CN102840578A discloses a parallel external fluidized bed heat exchanger, which has a good particle distribution effect. However, the fluidized bed heat exchanger fails to fully consider the uniform distribution of solid particles, and the circulation effect is also poor.

[0007] In summary, there is an urgent need to develop a new fluidized bed heat exchanger that can maintain high heat transfer efficiency over a long period of time. Summary of the Invention

[0008] The technical problem to be solved by this invention is that existing heat exchanger equipment is prone to adhesion and scaling in the tubes, which increases thermal resistance and significantly reduces heat exchange efficiency after long-term use. The present invention provides a self-cleaning fluidized bed heat exchanger with a dual-distribution component. This dual-distribution component self-cleaning fluidized bed heat exchanger has the technical feature of evenly distributing solid particles throughout the fluidized bed heat exchanger, maintaining high heat exchange efficiency over a long period of time, and has the advantage of uniform particle distribution.

[0009] In order to solve the above technical problems, the present invention provides a double-distribution component self-cleaning fluidized bed heat exchanger on the one hand, which includes a lower tube box 1, heat exchanger tubes 2, an upper tube box 3, a liquid-solid separation box 4, a downcomer 5, a solid particle tank 6, a liquid storage tank 7 and a liquid circulation pump 8; wherein the lower tube box 1 includes a bracket ring 9, a baffle 10, a diffuser 11 and a three-pronged bracket 12, the bracket ring 9 is fixed in the lower tube box 1, the baffle 10 is installed on the bracket ring 9, the three-pronged bracket 12 is installed above the bracket ring 9, the diffuser 11 is connected to the three-pronged bracket 12, the heat exchanger tubes 2 are connected to the upper tube box 3, the upper part of the upper tube box 3 is connected to the liquid-solid separation box 4, the liquid-solid separation box 4 is divided into an upper and a lower road, the lower road is connected to the solid particle tank 6 through the downcomer 5, the upper road is connected to the liquid storage tank 7, the liquid storage tank 7 is connected to the lower tube box 1 through the liquid circulation pump 8, and the solid particle tank 6 is connected to the pipeline from the liquid circulation pump 8 to the upper tube box 3.

[0010] In some preferred embodiments of the present invention, the double-distribution component self-cleaning fluidized bed heat exchanger further includes an elliptical elbow 13 , through which the solid particle tank 6 is connected to the pipeline from the liquid circulation pump 8 to the upper pipe box 3 .

[0011] The inventors of the present application have discovered through research that the self-cleaning fluidized bed heat exchanger with a double-distribution component having the above-mentioned structure can achieve uniform distribution of solid particles, thereby maintaining high heat transfer efficiency of the fluidized bed heat exchanger over a long period.

[0012] According to the present invention, the solid phase passes through the lower route and the liquid phase passes through the upper route. The upper route inlet is equipped with a sieve plate to prevent solid particles from passing through.

[0013] In some preferred embodiments of the present invention, the lower pipe box 1 is semi-cylindrical.

[0014] In some preferred embodiments of the present invention, the height of the lower tube box 1 is 0.5 to 0.8 times the height of the heat exchanger tubes 2 .

[0015] In some preferred embodiments of the present invention, the height of the lower tube box 1 is 0.55 to 0.75 times the height of the heat exchanger tubes 2 .

[0016] In some preferred embodiments of the present invention, the diameter of the lower pipe box 1 is 500 mm to 700 mm.

[0017] In some preferred embodiments of the present invention, the support ring 9 is fixed at 20% to 40% of the height of the lower pipe box 1 .

[0018] In some preferred embodiments of the present invention, the support ring 9 is fixed at one-third of the height of the lower pipe box 1 .

[0019] In some preferred embodiments of the present invention, the diffuser plate 11 is located at 45% to 55% of the height of the lower pipe box 1 .

[0020] In some preferred embodiments of the present invention, the diffuser plate 11 is located at 50% of the height of the lower pipe box 1 .

[0021] In some preferred embodiments of the present invention, the bracket ring 9 includes a circular ring 91 and a fixed bracket 92; the outer diameter of the circular ring 91 is the same as the diameter of the lower pipe box 1, and the inner diameter is 0.85 to 0.99 times the diameter of the lower pipe box 1; the fixed bracket 92 includes two connected stainless steel sheets, the length of the stainless steel sheet is 40 mm to 80 mm, and there is an angle between the two stainless steel sheets, the degree of the angle is preferably 135° to 150°, the number of the fixed brackets 92 is 2 to 6, the angles between two adjacent fixed brackets 92 are equal, one end of the fixed bracket 92 is fixed to the circular ring 91, and the other end has an inlaid structure for fixing the baffle 10.

[0022] In some preferred embodiments of the present invention, the baffle 10 is a porous flat plate with a thickness of 2.0 cm to 5.0 cm; the front structure of the baffle 10 is circular or square; the pore structure of the baffle 10 is selected from at least one of a cross type, a three-circle type and a triangle type, the porosity is 40% to 60%, and the equivalent diameter of the opening is 2 to 4 times the average particle size of the solid particles. For any two openings, the aperture of the opening farther from the center of the baffle 10 is greater than or equal to the aperture of the opening closer to the center of the baffle 10.

[0023] According to the present invention, the equivalent diameter of the baffle 10 is 0.6 to 0.8 times the diameter of the lower tube box 1 .

[0024] In some preferred embodiments of the present invention, the tripod bracket 12 is composed of two long brackets with a length of 30cm to 50cm and a short bracket with a length of 10cm to 20cm, and the angles between any two brackets are equal; wherein, the two long brackets are respectively fixed on the upper tube wall of the lower box tube 1, and the short bracket faces the bottom of the lower box tube 1 and is used to fix the diffuser plate 11.

[0025] According to the present invention, the diameter of the long bracket and / or the short bracket is 0.4 to 0.6 times the diameter of the heat exchanger tubes 2 .

[0026] According to the present invention, the center of the diffuser plate 11 is connected to the end point of the short bracket in the tripod bracket 12 .

[0027] In some preferred embodiments of the present invention, the diffuser plate 11 is a porous plate having a hole structure of regular circular small holes and inverted circular large holes, and a V-shaped side structure. Preferably, the diameter of the circular small holes is 1 to 2 times the average particle size of the solid particles, and the diameter of the circular large holes is 4 to 6 times the average particle size of the solid particles; the diffuser plate 11 is composed of two complete semicircular plates with a thickness of 2 cm to 4 cm, and the splicing angle is 90° to 140°; the bottom circular diameter of the diffuser plate 11 is 0.990 to 0.999 times the diameter of the lower box tube 1; the diffuser plate 11 can rotate counterclockwise with the center of the circle as the rotation point under external drive, and the speed is 10r / min to 30r / min.

[0028] In some preferred embodiments of the present invention, the liquid-solid separation box 4 is a gravity settling type or a hydrocyclone.

[0029] According to the present invention, the solid particles used in the double-distribution component self-cleaning fluidized bed heat exchanger, preferably inert solid particles, have a bulk density greater than the density of the circulating liquid and do not react with the medium used in the application. Preferably, they are one or more of zirconium silicate beads, corundum balls, porcelain balls, steel balls and engineering plastics; the average particle size of the solid particles used is 2 to 4 mm; the average mass solid content of the solid particles in the double-distribution component self-cleaning fluidized bed heat exchanger is 3% to 7%.

[0030] In another aspect, the present invention provides a method for preventing scaling in a top heat exchanger of a constant pressure reduction device, using the aforementioned dual-distribution component self-cleaning fluidized bed heat exchanger, wherein crude oil circulates in the heat exchanger tubes 2, and water circulates in the shell side. The crude oil is pumped from a liquid storage tank 7 through a liquid circulation pump 8 into a lower tube box 1, where it is mixed with solid particles flowing out through an elliptical elbow 13. The crude oil is then initially dispersed by a support ring 9 equipped with a baffle 10. The particles are then fluidized and evenly distributed by a diffuser 11, entering the heat exchanger tubes 2 and repeatedly flushing the walls of the heat exchanger tubes 2. Under the flushing of the solid particles, dirt is less likely to adhere to and aggregate on the walls of the heat exchanger tubes 2. Heat exchange is completed between the crude oil in the tube side and the water in the shell side. The solid particles and water are separated in a liquid-solid separation box 4, and finally the solid particles and water circulate in the dual-distribution component self-cleaning fluidized bed heat exchanger.

[0031] According to the present invention, solid particles circulate in the dual-distribution component self-cleaning fluidized bed heat exchanger, and liquid crude oil can be partially extracted from the liquid storage tank and sent to the subsequent system, or it can be not extracted and all used to complete the circulation.

[0032] In some preferred embodiments of the present invention, the flow rate of the crude oil in the heat exchanger tubes 2 of the double-distribution component self-cleaning fluidized bed heat exchanger is 2.0 m / s to 4.5 m / s.

[0033] In the technical solution and method of the present invention, the heat transfer coefficient is calculated based on the temperature difference between the inner wall temperature and the mainstream temperature and the heat flux, and the scaling condition of the tube is judged based on the change pattern of the heat transfer coefficient over time, thereby serving as a basis for judging the ability to maintain the heat transfer effect over a long period of time.

[0034] By adopting the technical solution of the present invention, a double-distribution component self-cleaning fluidized bed heat exchanger consisting of a lower tube box 1, heat exchanger tubes 2, an upper tube box 3, a liquid-solid separation box 4, a downcomer 5, a solid particle tank 6, a liquid storage tank 7, and a liquid circulation pump 8 is provided, wherein a bracket ring 9, a baffle 10, a diffusion plate 11, and a three-pronged bracket 12 are installed in the lower tube box 1. The good technical effect of maintaining a heat transfer coefficient of 95% of the original after 200 days of continuous operation is achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 FIG. 1 is a schematic diagram of a double-distribution-member self-cleaning fluidized bed heat exchanger according to one embodiment of the present invention.

[0036] Figure 2 The figure is a schematic diagram of the installation positions of the support ring, baffle, diffuser plate and three-pronged support of the lower tube box of the double distribution component self-cleaning fluidized bed heat exchanger according to one embodiment of the present invention.

[0037] Figure 3 Schematic diagram of the front and side structures of the support ring of a self-cleaning fluidized bed heat exchanger with double distribution components according to one embodiment of the present invention.

[0038] Figure 4 It is a front structural schematic diagram of a baffle of a double distribution component self-cleaning fluidized bed heat exchanger according to one embodiment of the present invention.

[0039] Figure 5 Schematic diagram of the front and side structures of a diffusion plate of a self-cleaning fluidized bed heat exchanger with a double distribution component according to one embodiment of the present invention.

[0040] Explanation of the accompanying figures: 1 is the lower tube box, 2 is the heat exchanger tube, 3 is the upper tube box, 4 is the liquid-solid separation box, 5 is the downcomer, 6 is the solid particle tank, 7 is the liquid storage tank, 8 is the liquid circulation pump, 9 is the bracket ring, 10 is the baffle, 11 is the diffuser plate, 12 is the three-pronged bracket, 13 is the elliptical elbow, 91 is the circular ring, and 92 is the fixed bracket. DETAILED DESCRIPTION

[0041] The present invention will be described in detail below with reference to the accompanying drawings and embodiments, but the protection scope of the present invention is not limited to the following description.

[0042] Figure 1-5In the figure, the bracket ring 9, the baffle 10, the diffuser 11, and the tripod bracket 12 are installed inside the lower tube box 1. The bracket ring 9 is installed and fixed at one-third of the height from the bottom of the lower tube box 1. The baffle 10 is fixed by the four fixed brackets 92 of the bracket ring 9. The diffuser 11 is located in the middle of the lower tube box 1, and its center is fixed to the end point of the short side of the tripod bracket 12. The two long sides of the tripod bracket 12 are respectively fixed to the wall of the lower tube box 1. The heat exchanger tubes 2 are connected to the upper tube box 3. The upper part of the upper tube box 3 is connected to the liquid-solid separation box 4. The liquid-solid separation box 4 is divided into two routes. The lower route passes through the solid phase, and the downcomer 5 is connected to the solid particle tank 6. The upper route passes through the liquid phase and flows into the liquid storage tank 7. The upper inlet is equipped with a sieve plate to prevent solid particles from passing through. The liquid in the liquid storage tank 7 is transported to the lower tube box 1 by the liquid circulation pump 8. The solid particles in the solid particle tank 6 are mixed with the liquid through the elliptical elbow 13 and flow into the lower tube box 1.

[0043] Crude oil flows from the liquid storage tank through 7, passes through a liquid circulation pump 8, and is pumped into the lower pipe box 1. Together with the inert solid particles flowing out of the elliptical elbow 13, it undergoes preliminary dispersion through a support ring 9 equipped with baffles 10. The particles are then fluidized and evenly distributed by a rotating diffusion disk 11 before entering the heat exchanger tubes 2, where they are repeatedly flushed against the walls of the tubes. The flushing of the solid particles prevents dirt from adhering to and agglomerating on the walls of the tubes 2. The crude oil in the tube side and the water in the shell side complete heat exchange. The solid particles and water are separated in the liquid-solid separation box 4. The liquid phase circulates back to the liquid storage tank 7, and the solid phase enters the solid particle tank 6 through a downcomer 5. The particles descending from the solid particle tank are mixed again with the liquid from the liquid storage tank 7 and enter the lower pipe box, completing the solid particle circulation.

[0044] Example 1

[0045] use Figure 1The double-distributed self-cleaning fluidized bed heat exchanger shown is used in the top heat exchanger of a certain plant's atmospheric and vacuum unit. It features 225 heat exchanger tubes, each 1500 mm long and Ø25 x 2.5 mm in diameter, arranged in a regular triangle. The lower tube box is 800 mm high. The solid particles are zirconium silicate with an average particle size of 3.5 mm. The average volume solids content within the double-distributed self-cleaning fluidized bed heat exchanger is 4.5%. The liquid phase is crude oil, and the flow rate is 3 m / s. The stainless steel sheet of the support ring is 60 mm long, with a 135° angle between the two sheets. The baffle is a circular plate with a thickness of 3 cm and a tri-circular pore structure. The equivalent diameter of the pores is 9 mm, and the porosity is 60%. The diffuser plate has a splicing angle of 100°, a thickness of 4 cm, and a rotation speed of 15 rpm. The diameter of the small hole on the front is 5 mm, and the diameter of the large hole on the back is 15 mm, with a porosity of 50%. The long leg of the three-pronged support is 40 cm long, and the short leg is 10 cm long and 15 mm in diameter. The liquid-solid separation box uses gravity settling. The downpipe has a diameter of 100 mm. Under these conditions, the heat transfer coefficient was 94% of the original value after 230 days of continuous operation.

[0046] Example 2

[0047] A dual-distribution self-cleaning fluidized bed heat exchanger, identical to that in Example 1, was used in the top heat exchanger of a certain factory's atmospheric and vacuum unit. The solid particles used were corundum spheres with an average particle size of 3 mm. The average volume solid content of the solid particles within the dual-distribution self-cleaning fluidized bed heat exchanger was 6%. The liquid phase was crude oil, and the flow rate was 3.5 m / s. The stainless steel sheet of the support ring was 75 mm long, with a 145° angle between the two stainless steel sheets. The baffle was a circular plate with a thickness of 2 cm and a triangular pore structure. The equivalent diameter of the pores was 10 mm, and the porosity was 45%. The diffuser plate had a splicing angle of 100°, a thickness of 3.5 cm, and a rotation speed of 20 rpm. The diameter of the small holes on the front was 4 mm, and the diameter of the large holes on the back was 16 mm, with a porosity of 45%. The long bracket of the tripod bracket was 35 cm long, and the short bracket was 8 cm long and 20 mm in diameter. The liquid-solid separation box was gravity-sedimentation-type. The diameter of the downcomer was 100 mm. Under this condition, the heat transfer coefficient was 96% of the original value after 200 days of continuous operation.

[0048] Example 3

[0049] A dual-distribution self-cleaning fluidized bed heat exchanger, identical to that in Example 1, was used in the top heat exchanger of a certain factory's atmospheric and vacuum unit. The solid particles used were porcelain balls with an average particle size of 2.5 mm. The average volume solid content of the solid particles within the dual-distribution self-cleaning fluidized bed heat exchanger was 5%. The liquid phase consisted of crude oil, with a flow rate of 2.5 m / s. The stainless steel sheet of the support ring was 55 mm long, with an angle of 150° between the two sheets. The baffle was a square plate with a thickness of 3 cm and a cross-shaped pore structure. The equivalent diameter of the pores was 8 mm, and the porosity was 55%. The diffuser plate had a splicing angle of 90°, a thickness of 4 cm, and a rotation speed of 30 rpm. The diameter of the small holes on the front was 3.5 mm, and the diameter of the large holes on the back was 15 mm, with a porosity of 50%. The long bracket of the tripod bracket was 45 cm long, and the short bracket was 7 cm long and 18 mm in diameter. The liquid-solid separation box employed gravity settling. The diameter of the downcomer was 100 mm. Under this condition, the heat transfer coefficient was 93% of the original value after 180 days of continuous operation.

[0050] Example 4

[0051] A dual-distribution self-cleaning fluidized bed heat exchanger, identical to that in Example 1, was used in the top heat exchanger of a certain factory's atmospheric and vacuum unit. Steel balls were used as solid particles with an average particle size of 3 mm. The average volume solid content of the solid particles within the dual-distribution self-cleaning fluidized bed heat exchanger was 4%. The liquid phase was crude oil, and the flow rate was 3 m / s. The stainless steel sheet of the support ring was 65 mm long, with an angle of 150° between the two stainless steel sheets. The baffle was a circular plate with a thickness of 4 cm and a cross-shaped pore structure. The equivalent diameter of the pores was 11 mm, and the porosity was 50%. The diffuser had a splicing angle of 110°, a thickness of 3.5 cm, a rotation speed of 15 rpm, a diameter of 4.5 mm for the small holes on the front, and a diameter of 14 mm for the large holes on the back, resulting in a porosity of 60%. The long bracket of the tripod bracket was 42 cm long, and the short bracket was 12 cm long and 18 mm in diameter. The liquid-solid separation box was gravity-sedimentation-type. The diameter of the downcomer was 100 mm. Under this condition, the heat transfer coefficient was 95% of the original value after 210 days of continuous operation.

[0052] Comparative Example 1

[0053] A fluidized bed heat exchanger was used in the top heat exchanger of a certain factory's atmospheric and vacuum unit. This fluidized bed heat exchanger was similar to the dual-distribution self-cleaning fluidized bed heat exchanger in Example 1, except that the support ring, baffle, diffuser, and trident support were omitted. The solid particles used were zirconium silicate with an average particle size of 3 mm. The average volume solids content of the solid particles within the dual-distribution self-cleaning fluidized bed heat exchanger was 5%. The liquid phase was crude oil, and the flow rate was 3 m / s. Under these conditions, the heat transfer coefficient was reduced to 60% of the original value after 150 days of continuous operation.

[0054] Comparative Example 2

[0055] A fluidized bed heat exchanger was used in the top heat exchanger of a certain factory's atmospheric and vacuum unit. This fluidized bed heat exchanger was similar to the dual-distribution self-cleaning fluidized bed heat exchanger in Example 1, except that the diffuser and tripod bracket were omitted. Ceramic balls with an average particle size of 3.4 mm were used as solid particles, and the average volume solids content within the dual-distribution self-cleaning fluidized bed heat exchanger was 6%. The liquid phase was crude oil, and the flow rate was 2.8 m / s. Under these conditions, the heat transfer coefficient was reduced to 77% of the original value after 180 days of continuous operation.

[0056] Comparative Example 3

[0057] A fluidized bed heat exchanger was used as the top heat exchanger in a certain factory's atmospheric and vacuum unit. This fluidized bed heat exchanger was similar to the dual-distribution self-cleaning fluidized bed heat exchanger in Example 1, except that the support ring and baffle were omitted. The solid particles used were alumina beads with an average particle size of 2.5 mm. The average volume solids content of the solid particles within the dual-distribution self-cleaning fluidized bed heat exchanger was 4%. The liquid phase was crude oil, and the flow rate was 4 m / s. Under these conditions, the heat transfer coefficient was 70% of the original value after 180 days of continuous operation.

[0058] It should be noted that the embodiments described above are only used to explain the present invention and do not constitute any limitation of the present invention. The present invention has been described with reference to typical embodiments, but it should be understood that the words used therein are descriptive and explanatory words, rather than restrictive words. The present invention may be modified as specified within the scope of the claims of the present invention, and the present invention may be revised without departing from the scope and spirit of the present invention. Although the present invention described therein relates to specific methods, materials and embodiments, it does not mean that the present invention is limited to the specific examples disclosed therein. On the contrary, the present invention can be extended to all other methods and applications with the same function.

Claims

1. A double-distribution component self-cleaning fluidized bed heat exchanger, characterized in that: The double-distribution component self-cleaning fluidized bed heat exchanger comprises a lower tube box (1), a heat exchanger tube (2), an upper tube box (3), a liquid-solid separation box (4), a downcomer (5), a solid particle tank (6), a liquid storage tank (7) and a liquid circulation pump (8); wherein the lower tube box (1) comprises a support ring (9), a baffle (10), a diffuser plate (11) and a three-pronged support (12); the support ring (9) is fixed in the lower tube box (1), the baffle (10) is installed on the support ring (9), and the three-pronged support (12) is installed on the support ring. (9), the diffuser plate (11) is connected to the three-pronged bracket (12), the heat exchanger tubes (2) are connected to the upper tube box (3), the upper part of the upper tube box (3) is connected to the liquid-solid separation box (4), the liquid-solid separation box (4) is divided into an upper path and a lower path, the lower path is connected to the solid particle tank (6) through the downcomer (5), the upper path is connected to the liquid storage tank (7), the liquid storage tank (7) is connected to the lower tube box (1) through the liquid circulation pump (8), and the solid particle tank (6) is connected to the pipeline from the liquid circulation pump (8) to the upper tube box (3); The baffle (10) is a porous flat plate; the pore structure of the baffle (10) is selected from at least one of a cross shape, a triangular shape, and a triangular shape, the opening rate is 40% to 60%, and the equivalent diameter of the opening is 2 to 4 times the average particle size of the solid particles; The diffuser plate (11) is a porous plate with a hole structure of regular circular small holes and inverted circular large holes, and a side structure of an inverted V shape; the diffuser plate (11) is formed by splicing two complete semicircular plates, and the splicing angle is 90° to 140°.

2. The fluidized bed heat exchanger according to claim 1, characterized in that The lower tube box (1) is semi-cylindrical; the height of the lower tube box (1) is 0.5 to 0.8 times the height of the heat exchanger tubes (2); the diameter of the lower tube box (1) is 500 mm to 700 mm; and / or The fluidized bed heat exchanger further includes an elliptical elbow (13), through which the solid particle tank (6) is connected to the pipeline from the liquid circulation pump (8) to the upper pipe box (3).

3. The fluidized bed heat exchanger according to claim 2, characterized in that The height of the lower tube box (1) is 0.55 to 0.75 times the height of the heat exchanger tubes (2).

4. The fluidized bed heat exchanger according to any one of claims 1 to 3, characterized in that: The support ring (9) is fixedly mounted at a height of 20% to 40% of the lower tube box (1); and / or The diffusion plate (11) is located at 45% to 55% of the height of the lower tube box (1).

5. The fluidized bed heat exchanger according to claim 4, characterized in that The support ring (9) is fixed at one-third of the height of the lower tube box (1); and / or The diffusion plate (11) is located at 50% of the height of the lower tube box (1).

6. The fluidized bed heat exchanger according to any one of claims 1 to 3, characterized in that: The support ring (9) comprises a circular ring (91) and a fixed support (92); The outer diameter of the ring (91) is the same as the diameter of the lower tube box (1), and the inner diameter is 0.85 to 0.99 times the diameter of the lower tube box (1); The fixing bracket (92) comprises two connected stainless steel sheets, the length of the stainless steel sheets is 40 mm to 80 mm, and there is an angle between the two stainless steel sheets. The number of the fixing brackets (92) is 2 to 6, and the angles between two adjacent fixing brackets (92) are equal. One end of the fixing bracket (92) is fixed to the ring (91), and the other end has an inlay structure for fixing the baffle (10).

7. The fluidized bed heat exchanger according to claim 6, characterized in that The angle between the two stainless steel sheets is between 135° and 150°.

8. The fluidized bed heat exchanger according to any one of claims 1 to 3, characterized in that: The baffle (10) has a thickness of 2.0 cm to 5.0 cm; the front structure of the baffle (10) is circular or square; For any two openings of the baffle (10), the aperture of the opening farther from the center of the baffle (10) is greater than or equal to the aperture of the opening closer to the center of the baffle (10).

9. The fluidized bed heat exchanger according to any one of claims 1 to 3, characterized in that: The three-pronged bracket (12) is composed of two long brackets with a length of 30 cm to 50 cm and a short bracket with a length of 10 cm to 20 cm, and the angles between any two brackets are equal; wherein the two long brackets are respectively fixed on the upper tube wall of the lower tube box (1), and the short bracket faces the bottom of the lower tube box (1) and is used to fix the diffuser plate (11).

10. The fluidized bed heat exchanger according to any one of claims 1 to 3, characterized in that: The diameter of the circular small holes of the diffusion plate (11) is 1 to 2 times the average particle size of the solid particles, and the diameter of the circular large holes of the diffusion plate (11) is 4 to 6 times the average particle size of the solid particles; The thickness of the diffusion plate (11) is 2 cm to 4 cm; The bottom circular diameter of the diffuser plate (11) is 0.990 to 0.999 times the diameter of the lower tube box (1); The diffusion plate (11) can rotate counterclockwise with the center of the circle as the rotation point under external drive, with a rotation speed of 10 r / min to 30 r / min.

11. The fluidized bed heat exchanger according to any one of claims 1 to 3, characterized in that: The liquid-solid separation box (4) is a gravity settling type or a hydrocyclone.

12. A method for preventing scaling of a top heat exchanger of a constant pressure and vacuum unit, using the fluidized bed heat exchanger according to any one of claims 1 to 11, wherein: Crude oil circulates in the heat exchanger tubes (2), and water circulates in the shell side. Crude oil is pumped from the liquid storage tank (7) through the liquid circulation pump (8) into the lower tube box (1), and after mixing with the solid particles flowing out through the elliptical elbow (13), it is initially dispersed by the support ring (9) equipped with a baffle (10). The particles are then fluidized and evenly distributed through the diffusion plate (11), and enter the heat exchanger tubes (2) and repeatedly flush the wall of the heat exchanger tubes (2). Under the flushing of the solid particles, dirt is not easy to adhere to the wall of the heat exchanger tubes (2); the crude oil in the tube side and the water in the shell side complete the heat exchange; the solid particles and crude oil are separated in the liquid-solid separation box (4), and finally the solid particles and crude oil circulate in the fluidized bed heat exchanger.

13. The method according to claim 12, characterized in that The flow rate of crude oil in the heat exchanger tubes (2) in the fluidized bed heat exchanger is 2.0 m / s to 4.5 m / s.

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