Self-cleaning fluidized bed heat exchanger and anti-fouling circulation method

Abstract

The present application relates to a kind of self-cleaning fluidized bed heat exchanger and prevent and remove scale circulating method, mainly to solve the technical problem that solid particles in the external circulation type fluidized bed heat exchanger of traditional technology cannot be fully circulated.The present application is by using a kind of self-cleaning fluidized bed heat exchanger, including: heat exchanger, liquid-solid accelerated separator, liquid storage tank, liquid circulating pump, downcomer, one-way controller, horizontal pipe, solid feeding tank;Wherein, the one-way controller includes inclined pipe and one-way valve;The technical scheme that the liquid-solid accelerated separator is equipped with motor-driven stirring device, preferably solves the problem, and can be used in the industrialization application of self-cleaning fluidized bed heat exchanger.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of chemical industry, in particular, to the field of long-period operation of chemical heat exchanger, and relates to a self-cleaning fluidized bed heat exchanger anti-fouling circulation method, which is widely used to solve the problem that solid particles in traditional external circulation fluidized bed heat exchanger cannot be fully circulated, affecting the long-period operation of the device. BACKGROUND

[0002] Heat exchangers are widely used in the petroleum, chemical, energy and other industries. However, as the use time increases, the heat exchanger inevitably has the phenomenon of dirt adhesion, thereby reducing the heat exchange efficiency of the heat exchanger and increasing the resistance, affecting the normal operation of the heat exchanger.

[0003] Developing a fluidized bed heat exchanger to replace the traditional heat exchanger can improve the heat exchange effect of the heat exchanger and effectively prolong the operation time of the device. Within the liquid flow rate range of the heat exchanger, whether the solid particles in the fluidized bed heat exchanger can be effectively circulated is the premise of restricting the normal operation and large-scale industrial application of the fluidized bed heat exchanger. In the traditional external circulation fluidized bed heat exchanger, due to the pipeline resistance and its distribution, the solid particles in the downcomer are easily blocked by the liquid column flowing horizontally in the circulation process, causing local short circuit of the downcomer pipeline fluid, preventing effective circulation of the solid particles, and affecting the application of the external circulation fluidized bed heat exchanger. Document CN202709856U discloses a horizontal liquid-solid circulation fluidized bed heat exchanger applying a Kenics static mixer. The solid particles in the fluidized bed heat exchanger cannot be effectively circulated, and the fluidized bed heat exchanger can only be used for horizontal heat exchangers. Document US6350928 discloses an external circulation fluidized bed heat exchanger without setting a clear solid particle circulation member, and the heat exchanger has weak ability to maintain heat transfer effect or cannot normally operate in the operation cycle. Document CN102921179 discloses an external circulation fluidized bed heat exchanger, which uses a reducer between the downcomer and the horizontal pipe to generate negative pressure to realize the circulation of the solid particles. The structure of the one-way controller involved in the external circulation fluidized bed heat exchanger has small operation flexibility space under matching process conditions, and it is difficult to realize effective circulation of the solid particles.

[0004] The present application provides a self-cleaning fluidized bed heat exchanger, which accelerates the speed of solid particles entering the horizontal pipe from the downcomer through a liquid-solid accelerated separator including a motor stirring device and a liquid-solid separation tank, and controls the flow direction and speed of the solid particles in the inclined pipe through a one-way controller including a one-way valve and an inclined pipe, so as to solve the above technical problems and realize stable and effective circulation of the solid particles in the external circulation fluidized bed heat exchanger. SUMMARY

[0005] One of the technical problems to be solved by the present application is that the solid particles in the external circulation type fluidized bed heat exchanger in the prior art cannot be fully circulated, and the present application provides a self-cleaning fluidized bed heat exchanger. The improved one-way controller and liquid-solid accelerated separator can fully accelerate the circulation of solid particles, and the self-cleaning fluidized bed heat exchanger has the advantages of full circulation of solid particles and long-period operation of the device.

[0006] Another technical problem to be solved by the present application is that the solid particles in the external circulation type fluidized bed heat exchanger in the prior art cannot be fully circulated, and the present application provides a circulation method of a self-cleaning fluidized bed heat exchanger, which adopts the self-cleaning fluidized bed heat exchanger described in the above solution to one of the technical problems.

[0007] To solve the above-mentioned one of the technical problems, the technical solution adopted by the present application is as follows: a self-cleaning fluidized bed heat exchanger, comprising: a heat exchanger, a liquid-solid accelerated separator 4, a liquid storage tank 6, a liquid circulating pump 7, a downcomer 8, a one-way controller 9, a horizontal pipe 10, and a solid feeding tank 11; wherein the heat exchanger comprises a lower pipe box 1, heat exchanger tubes 2, and an upper pipe box 3, the lower pipe box 1 is connected to one end of the horizontal pipe 10, and the other end of the horizontal pipe 10 is connected to the liquid circulating pump 7; the liquid-solid accelerated separator 4 is connected to the horizontal pipe 10 segment between the lower pipe box 1 and the liquid circulating pump 7 through the downcomer 8; the solid feeding tank is connected to the horizontal pipe 10 segment between the downcomer 8 and the lower pipe box 1; the one-way controller 9 is located at the connection between the horizontal pipe 10 and the downcomer 8, and communicates the downcomer and the horizontal pipe.

[0008] In the above technical solution, the one-way controller 9 preferably comprises an inclined pipe 18 and a one-way valve 19; wherein the one-way valve 19 is located in the inclined pipe 18; the inclined pipe 18 is installed at the intersection of the horizontal pipe 10 and the downcomer 8, and the included angle between the inclined pipe 18 and the horizontal pipe 10 is 30°-90°; further preferably, the diameter of the inclined pipe 18 is equal to that of the downcomer 8, and the diameter ratio of the inclined pipe 18 to the horizontal pipe 10 is 0.1-0.9.

[0009] In the above technical solution, the one-way valve 19 preferably comprises a spring piece C, an upper baffle B, a rotating shaft A, and a partition baffle D; wherein the spring piece C and the partition baffle D can rotate along the rotating shaft A, and the upper end surface of the spring piece C realizes adhesion and separation with the lower end surface of the upper baffle B through rotation. Wherein the upper baffle B is located at the connection between the downcomer and the inclined pipe and is at the lowermost end of the downcomer; the spring piece C and the rotating shaft A are both located at the connection between the downcomer and the inclined pipe and are at the uppermost end of the inclined pipe; the partition baffle D is located inside the inclined pipe and intersects with the spring piece C, and the intersection line is located on the plane of the spring piece C.

[0010] In the above technical solution, the elastic sheet C in the one-way valve (19) is preferably a circular flat plate, and the diameter of the elastic sheet C is preferably equal to the diameter of the downcomer 8.

[0011] In the above technical solution, the partition baffle D is preferably a flat baffle, and the upper end of the partition baffle D is preferably connected to the elastic sheet C. The intersection line of the partition baffle D and the elastic sheet C divides the elastic sheet C into two partitions. Further preferably, the area ratio of the partition of the elastic sheet C close to the upper baffle B to the total area of the elastic sheet C is preferably 0.5-1; the projection length of the length of the partition baffle D extending into the horizontal pipe (10) in the vertical direction to the diameter of the horizontal pipe (10) is preferably 0.05-1; and the included angle between the partition baffle D and the inclined pipe axis E is preferably 0°-60°.

[0012] In the above technical solution, the liquid-solid accelerated separator comprises a stirring device and a liquid-solid separation tank. As a preferred solution, the stirring device is preferably a motor stirring device, which is more preferably composed of an external motor 16 and an internal stirring paddle 17; the liquid-solid separation tank is preferably composed of a cylinder and a lower head connected to the cylinder, and the lower head is preferably a reduced-diameter truncated cone or a spherical surface. The diameter of the upper end surface of the lower head is equal to the diameter of the cylinder, and the height of the lower head is preferably 0.2-2 times the diameter of the cylinder; a particle filter plate 5 is preferably arranged in the liquid-solid separation tank, and the particle filter plate 5 is located below the liquid pipeline.

[0013] In the above technical solution, the motor drives the stirring paddle to rotate for stirring, and the stirring speed is 150-1000 rpm.

[0014] In the above technical solution, the system comprises the one-way valve (19) and the inclined pipe (18), the one-way valve (19) is located at the joint of the descending pipe (8) and the inclined pipe (18) in the initial stage, the descending solid particles are deposited on the upper end of the spring C of the one-way valve (19) after the main valve (12) of the descending pipe (8) is opened, the one-way valve spring C and the one-way valve flapper B are closely attached when the weight of the solid particles deposited on the upper end of the one-way valve (19) is less than the upward thrust of the liquid phase, the one-way valve (19) is closed; when the weight of the solid particles deposited on the upper end of the one-way valve (19) is greater than the thrust of the water below, the spring C and the partition baffle D rotate along the rotating shaft A, away from the one-way valve flapper B, and the one-way valve (19) is opened. Due to the fact that the partition baffle D divides the inclined pipe (18) into two partitions, the liquid flow outlet channel at the intersection of the horizontal pipe (10) and the inclined pipe (18) is narrowed, the liquid flow velocity increases after passing through the partition baffle D, a negative pressure is formed at the outlet on the side of the baffle close to the upper flapper B, and the solid particles in the inclined pipe (18) and the water in the liquid storage tank (6) extracted by the liquid circulating pump (7) enter the heat exchanger tube (2) through the horizontal pipe (10) under the action of the negative pressure suction force of the outlet negative pressure; the liquid-solid mixture flows out of the heat exchanger tube (2) into the liquid-solid accelerated separator (4) from the upper pipe header (3); the separated liquid circulating water overflows from the particle filter plate (5) and then enters the liquid storage tank (6), and the separated stream containing most of the solid particles flows through the descending pipe (8) to the horizontal pipe, and enters the heat exchanger tube (2) again through the horizontal pipe (10) under the action of the suction force of the one-way controller (9) and the water extracted by the liquid circulating pump (7) to complete the circulation.

[0015] In the above technical solution, the ratio of the pore diameter of the particle filter plate (5) to the diameter of the solid particles is preferably 0.2-0.9.

[0016] In the above technical solution, the descending pipe (8) is preferably provided with a main valve (12), an upper metering valve (13), a lower metering valve (14) and a metering tank (15); the upper metering valve (13) and the lower metering valve (14) are arranged on the branch pipes connected to the descending pipe (8) from top to bottom, the metering tank (15) is connected between the upper and lower branch pipes, and the main valve (12) is arranged on the descending pipe (8) between the connection points of the upper and lower branch pipes.

[0017] In the above technical solution, the upper metering valve (13) is closed, the main valve (12) is opened, the solid particles are metered, the lower metering valve (14) is opened after the metering is completed, and the solid particles enter the descending pipe (8) to continue the solid particle circulation in the fluidized bed heat exchanger.

[0018] In the above technical solution, the main valve (12) and the lower metering valve (14) are closed, the upper metering valve (13) is opened, the solid particles enter the metering tank (15), and the metering is completed.

[0019] In the above technical solution, the metering tank (15) is preferably made of transparent material, and the inner wall of the metering tank (15) is marked with scales according to the volume.

[0020] To solve the second technical problem, the technical solution of the present application is as follows: a circulating method of a self-cleaning fluidized bed heat exchanger, which adopts the technical solution of any one of the self-cleaning fluidized bed heat exchanger described in the first technical problem.

[0021] In the technical solution, the solid particles used in the fluidized bed heat exchanger are preferably inert particles that do not react with the medium in the system of the use site, and the bulk density of the solid particles is greater than the liquid density. Further preferably, the solid particles are one or more of zirconium silicate beads, corundum balls, porcelain balls, aluminum oxide beads, zirconium silicate beads, zirconium silicate, steel balls, engineering plastics, polyformaldehyde particles, polytetrafluoroethylene particles, small stones, chopped metal wires, and rubber balls, and more preferably zirconium silicate, aluminum oxide beads, and zirconium silicate beads.

[0022] In the technical solution, the circulating water flow rate operating range of the heat exchanger of the fluidized bed heat exchanger is preferably 0.8-4 m / s.

[0023] In the technical solution and method of the present application, the solid particle circulation effect is characterized by the mass circulation amount of the solid particles in the metering tank 4 per unit time during stable operation. The calculation method of the mass circulation amount of the solid particles in the metering tank 4 is as follows:

[0024] Solid particle mass circulation amount = solid particle density x total volume of metering tank scale portion x metering tank scale reading / time

[0025] The present application provides a self-cleaning fluidized bed heat exchanger, which accelerates the speed of solid particles entering the horizontal pipe from the descending pipe through a liquid-solid accelerated separator including a motor stirring device and a liquid-solid separation tank, and forms a strong suction negative pressure at the intersection of the descending pipe and the horizontal pipe through a one-way controller including a one-way valve and an inclined pipe, thereby realizing effective circulation of solid particles in the heat exchanger tube and solving the above problems.

[0026] By using the technical solution of the present application, the flow direction and speed of the solid particles in the inclined pipe are controlled through the liquid-solid accelerated separator and the one-way controller including the one-way valve and the inclined pipe, thereby realizing effective circulation of the solid particles in the heat exchanger tube, and the mass circulation amount of the solid particles is more than 444 g / min, which achieves good technical effects. BRIEF DESCRIPTION OF DRAWINGS

[0027] Figure 1 The present application provides a self-cleaning fluidized bed heat exchanger, which accelerates the speed of solid particles entering the horizontal pipe from the descending pipe through a liquid-solid accelerated separator including a motor stirring device and a liquid-solid separation tank, and forms a strong suction negative pressure at the intersection of the descending pipe and the horizontal pipe through a one-way controller including a one-way valve and an inclined pipe, thereby realizing effective circulation of solid particles in the heat exchanger tube and solving the above problems.

[0028] Figure 2 The present application provides a self-cleaning fluidized bed heat exchanger, which accelerates the speed of solid particles entering the horizontal pipe from the descending pipe through a liquid-solid accelerated separator including a motor stirring device and a liquid-solid separation tank, and forms a strong suction negative pressure at the intersection of the descending pipe and the horizontal pipe through a one-way controller including a one-way valve and an inclined pipe, thereby realizing effective circulation of solid particles in the heat exchanger tube and solving the above problems.

[0029] Figure 1In this diagram, 1 is the lower tube box; 2 is the heat exchanger tubes; 3 is the upper tube box; 4 is the liquid-solid accelerating separator; 5 is the particle filter plate; 6 is the liquid storage tank; 7 is the liquid circulation pump; 8 is the downcomer; 9 is the one-way controller; 10 is the horizontal pipe; 11 is the feed tank; 12 is the downcomer flow control valve; 13 and 14 are metering valves; 15 is the metering tank; 16 is the motor; 17 is the agitator; 18 is the inclined pipe; and 19 is the one-way valve.

[0030] The upper pipe box 3 is connected to the liquid-solid accelerating separator 4. The liquid-solid accelerating separator 4 splits into two paths: one solid phase path is connected to the one-way controller 9 located at the intersection of the downcomer 8 and the horizontal pipe 10; the other liquid phase path connects from the upper part of the particle filter plate 5 to the solid particle tank 6. The solid particle tank 6 is connected to the liquid circulation pump 7, which is connected to the horizontal pipe 10. The circulation rate of solid particles is measured by control valves 12, 13, and 14.

[0031] Figure 2 In the diagram, 18 is an inclined pipe; 19 is a check valve. A is the check valve shaft, B is the check valve baffle, C is the check valve spring, and D is the partition baffle. When the weight of the solid particles deposited above the check valve spring C is less than the thrust of the water below, the check valve spring C and the check valve baffle B are in close contact; when the weight of the solid particles deposited above the check valve spring C is greater than the thrust of the water below, the spring C rotates along the shaft A, moves away from the check valve baffle B, and the check valve 19 opens.

[0032] The present invention will be further illustrated below with examples and comparative examples, but the method of the present invention is not limited thereto. Detailed Implementation

[0033] The method of the present invention will be further described below with reference to embodiments.

[0034]

Example 1

[0035] use Figure 1 The diagram shows a scale-preventing circulating fluidized bed heat exchanger. This fluidized bed heat exchanger contains 123 heat exchange tubes, each 1000 mm long and with a diameter of Φ22 × 1.5 mm, arranged in a square pattern. Horizontal tubes have a diameter of 50 mm, and downcomers have a diameter of 25 mm. The liquid phase is water. The solid particles are zirconium silicate with an average particle size of 2 mm, and the average volumetric solids content of the solid particles within the fluidized bed heat exchanger is 3%. The liquid phase is water, and the flow velocity is 1 m / s.

[0036] In the one-way controller system, the angle between the inclined tube and the horizontal tube is 45°, and the diameter ratio between the inclined tube and the horizontal tube is 0.5. The diameter of the spring C in the one-way valve is 25mm. The ratio of the area of ​​the section near the upper baffle B in the spring C section to the area of ​​the spring C is 0.7. The ratio of the vertical projection length of the section baffle D extending into the horizontal tube (10) to the diameter of the horizontal tube (10) is 0.5. The angle between the section baffle D and the axis E of the inclined tube is 0°. The stirring speed of the motor is 500rpm. Under these conditions, after stable operation, the mass circulation rate of solid particles in the metering tank is measured to be 444g / min.

[0037]

Examples 2-7

[0038] use Figure 1 The circulating fluidized bed heat exchanger shown is a descaling circulating heat exchanger. This fluidized bed heat exchanger contains 123 heat exchange tubes, each 1000mm long with a diameter of Φ22×1.5mm, arranged in a square pattern. The horizontal tubes have a diameter of 50mm, the downcomer tubes have a diameter of 25mm, and the diameter of the spring C in the one-way valve is 25mm. The liquid phase is water. Based on Example 1, the angle between the inclined and horizontal tubes (A1), the diameter ratio between the inclined and horizontal tubes (L1), the ratio of the area of ​​the section near the upper baffle B in spring C to the area of ​​spring C (S), the ratio of the vertical projection length of the section baffle D extending into the horizontal tube (10) to the diameter of the horizontal tube (10) (L2), the angle between the section baffle D and the axis E of the inclined tube (A2), and the motor stirring speed (SP) were changed. After stable operation, the circulating solid particle mass (MT) was measured, and the results are listed in Table 1.

[0039] Table 1

[0040]

[0041] Comparative Example 1

[0042] use Figure 1 The diagram shows a scale-preventing circulating fluidized bed heat exchanger. This fluidized bed heat exchanger contains 123 heat exchange tubes, each 1000 mm long and with a diameter of Φ22 × 1.5 mm, arranged in a square pattern. The horizontal tubes have a diameter of 50 mm, and the downcomers have a diameter of 25 mm. The liquid phase is water. In the one-way controller system, the inclined tube has a diameter of 25 mm, the angle between the inclined and horizontal tubes is 45°, and the diameter ratio of the inclined to the horizontal tubes is 0.5. The diameter of the spring C in the one-way valve is 25 mm.

[0043] Based on Example 1, no motor stirring device was installed. After stable operation, the mass circulation rate of solid particles was measured to be 221 g / min. -1 The cycle effect is not good.

[0044] Comparative Example 2

[0045] use Figure 1 The diagram shows a descaling circulating fluidized bed heat exchanger. This fluidized bed heat exchanger contains 123 heat exchange tubes, each 1000 mm long and Φ22×1.5 mm in diameter, arranged in a square pattern. Horizontal tubes have a diameter of 50 mm, and downcomers have a diameter of 25 mm. The liquid phase is water. In the liquid-solid accelerating separator, the motor stirring speed is 500 rpm. Based on Example 1, a unidirectional controller system is not installed. After stable operation, the measured solid particle circulation rate is 288 g / min. -1 The cycle effect is not good.

[0046] Comparative Examples 3-8

[0047] use Figure 1 The scale-preventing circulating fluidized bed heat exchanger shown is equipped with 123 heat exchange tubes, each 1000 mm long and Φ22×1.5 mm in diameter, arranged in a square. The horizontal tubes have a diameter of 50 mm, and the downcomer tubes have a diameter of 25 mm. The liquid phase is water. Based on Example 1, the angle between the inclined tube and the horizontal tube (A1), the diameter ratio between the inclined tube and the horizontal tube (L1), the ratio of the area of ​​the section near the upper baffle B in the spring plate C to the area of ​​the spring plate C (S), the ratio of the vertical projection length of the section baffle D extending into the horizontal tube (10) to the diameter of the horizontal tube (10) (L2), the angle between the section baffle D and the axis E of the inclined tube (A2), and the motor stirring speed (SP) were changed. After stable operation, the mass circulation of solid particles (MT) was measured, and the results are listed in Table 2.

[0048] Table 2

[0049]

Claims

1. A self-cleaning fluidized bed heat exchanger comprising: The heat exchanger, liquid-solid accelerated separator (4), liquid storage tank (6), liquid circulating pump (7), downcomer (8), one-way controller (9), horizontal pipe (10), solid feeding tank (11); wherein, the heat exchanger comprises lower pipe box (1), heat exchanger tube (2) and upper pipe box (3), the lower pipe box (1) is connected with one end of the horizontal pipe (10), the other end of the horizontal pipe (10) is connected with the liquid circulating pump (7); the liquid-solid accelerated separator (4) is connected with the section of the horizontal pipe (10) between the lower pipe box (1) and the liquid circulating pump (7) through the downcomer (8); the section of the horizontal pipe (10) between the downcomer (8) and the lower pipe box (1) is connected with the solid feeding tank; the one-way controller (9) is located at the connection of the horizontal pipe (10) and the downcomer (8), and communicates the downcomer and the horizontal pipe; The liquid-solid accelerated separator comprises a stirring device and a liquid-solid separation tank. The one-way controller (9) comprises an inclined pipe (18) and a one-way valve (19); wherein, the one-way valve (19) is located in the inclined pipe (18); the inclined pipe (18) is installed at the intersection of the horizontal pipe (10) and the downcomer (8), and the included angle between the inclined pipe (18) and the horizontal pipe (10) is 30°-90°. The one-way valve (19) comprises a spring piece C, an upper baffle B, a rotating shaft A and a partition baffle D; wherein, the spring piece C and the partition baffle D can rotate along the rotating shaft A, and the upper end surface of the spring piece C is in contact with or separated from the lower end surface of the upper baffle B through rotation; The upper baffle B is located at the connection of the downcomer and the inclined pipe and at the lowermost end of the downcomer; the spring piece C and the rotating shaft A are both located at the connection of the downcomer and the inclined pipe and at the uppermost end of the inclined pipe; the partition baffle D is located in the inclined pipe and intersects with the spring piece C, and the intersection line is located on the plane of the spring piece C; The partition baffle D is a plane baffle; the upper end of the partition baffle D is connected with the spring piece C, and the intersection line of the partition baffle D and the spring piece C divides the spring piece C into two partitions; The diameter ratio of the inclined pipe (18) to the horizontal pipe (10) is 0.1-0.9; the area ratio of the partition of the spring piece C close to the upper baffle B to the total area of the spring piece C is 0.5-1; the ratio of the projection length of the length of the partition baffle D deep into the horizontal pipe (10) in the vertical direction to the diameter of the horizontal pipe (10) is 0.05-1; the included angle between the partition baffle D and the axis E of the inclined pipe (18) is 0°-60°; The stirring device is a motor stirring device; the liquid-solid separation tank is composed of a cylinder and a lower head connected with the cylinder, the diameter of the upper end surface of the lower head is equal to the diameter of the cylinder, and the height of the lower head is 0.2-2 times the diameter of the cylinder; the motor drives the stirring paddle to rotate for stirring, and the stirring speed is 150-1000 rpm.

2. The self-cleaning fluidized bed heat exchanger of claim 1, wherein, The diameter of the inclined pipe (18) is equal to that of the downcomer (8).

3. The self-cleaning fluidized bed heat exchanger of claim 1, wherein, The spring piece C is circular, and the diameter of the spring piece C is equal to that of the downcomer (8).

4. The self-cleaning fluidized bed heat exchanger of claim 1, wherein, The motor stirring device is composed of an external motor (16) and an internal stirring paddle (17).

5. The self-cleaning fluidized bed heat exchanger of claim 1, wherein, The lower head is a reduced-diameter truncated cone or a spherical surface.

6. The self-cleaning fluidized bed heat exchanger of claim 1, wherein, A particle filter plate (5) is arranged in the liquid-solid separation tank, and the particle filter plate (5) is located below the liquid pipeline.

7. A circulating method of a self-cleaning fluidized bed heat exchanger, using the self-cleaning fluidized bed heat exchanger according to any one of claims 1 to 6.

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