Water-cooled elbow for high-temperature titanium dioxide single-tube heat exchange

Abstract

This invention discloses a cooling elbow for a single-pipe heat exchanger of high-temperature titanium dioxide, comprising a pipe with a rectangular cross-section and an arc-shaped longitudinal section. A reinforcing layer is provided on the inner side of the material impact zone on the outer arc wall of the pipe, and a flow-guiding heat dissipation plate is also provided on the inner side of the outer arc wall. By designing the elbow as a rectangular pipe with a small curvature and an expanded diameter, this invention reduces material flow velocity and pressure. The angled flow-guiding heat dissipation plate on the inner wall of the elbow changes the airflow direction, mitigates material impact, and accelerates heat dissipation. The quickly removable and replaceable reinforcing layer on the material impact zone of the inner wall of the elbow increases the wear resistance of easily worn areas, prevents material erosion of the pipe, and ensures long-term operation of the elbow.

Description

Technical Field

[0001] This invention belongs to the field of chemical production technology, and specifically relates to a water-cooled elbow for high-temperature titanium dioxide single-tube heat exchange. Background Technology

[0002] In the chloride process of titanium dioxide production, TiCl4 undergoes a high-temperature oxidation reaction in the oxidation furnace, generating high-temperature chlorine gas and TiO2. To prevent TiO2 from adhering to the downstream pipelines, causing blockages, reduced heat exchange efficiency, and excessively high temperatures in subsequent stages, descaling sand is added to the pipelines to clean the TiO2 adhering to the inner walls. Simultaneously, to lower the temperature, the downstream pipelines need to be placed in circulating cooling water. Within the downstream pipelines, due to the high reaction temperature and rapid gas flow, the high-speed flow of high-temperature chlorine gas, high-temperature substrate, and descaling sand causes frequent erosion and wear at the pipe bends, leading to pipe wear-through, chlorine gas leakage, and system shutdown. This not only pollutes the environment but also affects the long-term stable operation of the system. Summary of the Invention

[0003] The purpose of this invention is to provide a water-cooled elbow for high-temperature titanium dioxide single-tube heat exchange, in order to overcome the shortcomings of the prior art.

[0004] The objective of this invention is achieved through the following technical solution:

[0005] A water-cooled elbow for high-temperature titanium dioxide single-pipe heat exchange includes a pipe with a rectangular cross-section and an arc-shaped longitudinal section;

[0006] The curvature of the pipe is 7-9D. A reinforcing layer is provided on the inner side of the material impact area of ​​the outer arc wall of the pipe. The outer arc wall at the reinforcing layer is separately set and detachably connected to the adjacent outer arc wall. The material impact area of ​​the pipe is an appropriately expanded area to the left and right sides centered on the material impact point. The material impact point is the intersection of the center lines DA and EK of the two end faces of the pipe and the outer arc wall, i.e., points A and K. The material impact angle is <23°, which is the angle between lines AB and AC. Line AB is located on the center line DA of the pipe end face, and line AC is the tangent of the outer arc wall at point A.

[0007] Multiple evenly distributed heat dissipation plates are provided on the inner side of the outer arc wall of the pipe, and the heat dissipation plates are inclined along the feeding direction.

[0008] Preferably, both ends of the pipe are provided with a reducing connector.

[0009] Preferably, the heat dissipation plate is located on the inner side of the non-material impact area of ​​the outer arc wall of the pipe.

[0010] Preferably, the tilt angle of the heat dissipation plate is 25 to 45°.

[0011] Preferably, the outer arc wall at the reinforcing layer is detachably connected to the adjacent outer arc wall by a concave-convex fit connection, and the fit is sealed by welding.

[0012] Preferably, the outer arc wall of the reinforcing layer is provided with bosses at both ends, and the adjacent outer arc wall ends are provided with corresponding grooves.

[0013] Preferably, the reinforcing layer is a zirconium-aluminum composite ceramic layer.

[0014] Preferably, a dovetail groove is provided on the inner side of the outer arc wall of the material impact zone of the pipeline, and the reinforcing layer is fixed in the dovetail groove.

[0015] Preferably, the reinforcing layer is fixed to the outer arc wall by a secondary adhesive bonding process.

[0016] Preferably, the water-cooled elbow also includes an online ultrasonic thickness gauge for measuring the thickness of the reinforcing layer and the pipe online.

[0017] This invention reduces material flow rate and pressure by setting the elbow as a rectangular pipe. By setting a flow guide and heat dissipation plate on the inner wall of the elbow, the impact of the material can be reduced and heat dissipation can be accelerated. By setting a reinforcing layer on the material impact area of ​​the inner wall of the elbow, the wear resistance of the wear-prone area can be increased, preventing the material from eroding the pipe and ensuring the long-term operation of the elbow. Attached Figure Description

[0018] Figure 1 This is a structural schematic diagram of the water-cooled elbow for high-temperature titanium dioxide single-tube heat exchange provided in this application;

[0019] Figure 2 yes Figure 1 Enlarged view of the Y-section;

[0020] Among them, 1-pipe; 2-flow guide heat dissipation plate; 3-reinforcing layer; 4-connector; 5-ultrasonic thickness gauge; 6-dovetail groove; 7-outer arc wall of reinforcing layer; 8-bore; 9-groove; 10-weld point. Detailed Implementation

[0021] This invention provides a water-cooled elbow for high-temperature titanium dioxide single-tube heat exchange, such as... Figure 1 As shown, it includes pipe 1 with a rectangular cross-section and an arc-shaped longitudinal section (section DE as shown in the figure).

[0022] The pipe has a curvature of 7–9D (pipe diameter), and a reinforcing layer 3 is provided inside the material impact zone of the outer arc wall of the pipe. The material impact zone of the pipe is an appropriately expanded area to the left and right of the material impact point. The material impact point is the intersection of the center lines DA and EK of the two end faces of the pipe with the outer arc wall, i.e., points A and K. The material impact angle β < 23°, which is the angle between lines AB and AC. Line AB is located on the center line DA of the pipe end face, and line AC is the tangent of the outer arc wall at point A. The outer arc wall at the reinforcing layer is separately set and detachably connected to the adjacent outer arc wall, facilitating quick replacement of the reinforcing layer.

[0023] The inner side of the outer arc wall of the pipe is also provided with multiple evenly distributed flow guiding and heat dissipation plates 2. The flow guiding and heat dissipation plates are inclined downward along the feeding direction. The gas-solid particles flow evenly with the fluid through the flow guiding and heat dissipation plates, and at the same time, the heat is concentrated and transferred, which reduces the temperature of the outer arc wall, ensures the material strength, and thus effectively reduces the wear of the outer arc wall.

[0024] In existing technologies, both straight heat exchange pipes and connecting elbows are circular pipes, which are prone to wear during production. This invention addresses this by designing the elbow as a rectangular pipe. During use, both ends of the elbow are connected to ordinary straight heat exchange pipes, and the entire heat exchange pipe is placed in circulating cooling water. The gas-solid mixture enters the rectangular pipe 1 through the ordinary circular straight pipe. The increased diameter of the rectangular pipe reduces the flow velocity and pressure of the medium within the pipe, thus minimizing the impact of the material on the elbow. Furthermore, this invention sets the elbow to have a small curvature and a large radius (curvature of 7-9D), reducing the impact angle β between the material and the outer arc wall to within 23°, significantly mitigating the direct impact of the material on the elbow. Simultaneously, since the material impact area is a wear-prone area, a quickly removable and replaceable reinforcing layer is installed here, which can significantly extend the pipe's operating cycle and prevent direct erosion of the elbow body. Additionally, this application features an inclined flow-guiding heat dissipation plate on the inner wall of the outer arc, which changes the airflow direction, reduces the impact of solid particles on the outer arc wall, and accelerates heat dissipation, thereby effectively reducing wear on the outer arc wall of the elbow body and ensuring long-term operation of the elbow.

[0025] Therefore, this invention reduces material flow velocity and pressure by setting the elbow as a rectangular pipe with a small curvature and an expanded diameter. Furthermore, by installing an angled flow-guiding and heat-dissipating plate on the inner wall of the elbow, the airflow direction can be changed, the impact of materials can be mitigated, and heat dissipation can be accelerated. By providing a quickly removable and replaceable reinforcing layer on the material impact area of ​​the elbow's inner wall, the wear resistance of easily worn areas can be increased, preventing material erosion of the pipe and ensuring long-term operation of the elbow. Preferably, both ends of the pipe are equipped with a reducing connector 4 (e.g., a round-to-square shape). Figure 1 The MD and EN sections shown serve as transition connections between ordinary circular pipes or circular joints such as flanges and rectangular pipes.

[0026] Preferably, the heat dissipation plate is located on the inner side of the non-material impact area of ​​the outer arc wall of the pipe, that is, no heat dissipation plate is installed at the reinforcement layer.

[0027] Preferably, the central angle α of the pipe is 90° (i.e., the angle between OD and OE). However, the central angle of the pipe can be set to other angles, such as 45°, 135°, etc., depending on the connection requirements.

[0028] Preferably, the tilt angle of the heat dissipation plate is 25 to 45°, which can reflect the incoming airflow, change the airflow direction, and reduce the impact on the outer arc wall.

[0029] Preferably, the reinforcing layer is a zirconium-aluminum composite ceramic layer.

[0030] Preferred, such as Figure 2 As shown, the outer arc wall 7 at the reinforcing layer is detachably connected to the adjacent outer arc wall via a convex-concave fit connection. Specifically, bosses 9 are provided at both ends of the outer arc wall at the reinforcing layer, and corresponding grooves 10 are provided at the ends of the adjacent outer arc walls. The fit is also sealed by welding to prevent leakage. When the reinforcing layer needs to be replaced, the weld 10 is cut open, and the reinforcing layer along with its outer arc wall is removed. Then, a new reinforcing layer is replaced, and the bosses and grooves of the replaced outer arc wall are fitted together and re-welded.

[0031] Preferably, a dovetail groove 6 is welded to the inner side of the outer arc wall of the material impact zone in the pipeline, and the reinforcing layer is fixed inside the dovetail groove. More preferably, the reinforcing layer is secondary fixed to the outer arc wall by bonding with high-temperature inorganic adhesive.

[0032] Preferably, the pipes in this application are made of Inconel 600 material (nickel-chromium-iron based solid solution reinforced alloy), which can resist high-temperature chlorine corrosion.

[0033] Preferably, the water-cooled elbow also includes an online ultrasonic thickness gauge 5, which is used to measure the thickness of the reinforcing layer and the pipe online. It can continuously detect the thickness of the reinforcing layer and the pipe, provide early warning, and avoid pipe leakage.

[0034] Although preferred embodiments of the invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including both the preferred embodiments and all changes and modifications falling within the scope of the invention. Clearly, those skilled in the art can make various alterations and modifications to the invention without departing from its spirit and scope. Thus, if these modifications and modifications of the invention fall within the scope of the claims and their equivalents, the invention is also intended to include these modifications and modifications.

Claims

1. A water-cooled elbow for high-temperature titanium dioxide single-tube heat exchange, characterized in that, This includes pipes with a rectangular cross-section and an arc-shaped longitudinal section; The curvature of the pipe is 7~9D. A reinforcing layer is provided on the inner side of the material impact area of ​​the outer arc wall of the pipe. The outer arc wall at the reinforcing layer is separately set and detachably connected to the adjacent outer arc wall. The material impact area of ​​the pipe is an appropriately expanded area to the left and right sides centered on the material impact point. The material impact point is the intersection of the center lines DA and EK of the two end faces of the pipe and the outer arc wall, i.e., points A and K. The material impact angle is <23°, which is the angle between lines AB and AC. Line AB is located on the center line DA of the pipe end face, and line AC is the tangent of the outer arc wall at point A. Multiple evenly distributed heat dissipation plates are provided on the inner side of the outer arc wall of the pipe. The heat dissipation plates are inclined downward along the feeding direction. The heat dissipation plates are located on the inner side of the non-material impact area of ​​the outer arc wall of the pipe.

2. The water-cooled elbow for high-temperature titanium dioxide single-tube heat exchange as described in claim 1, characterized in that, Both ends of the pipe are equipped with a reducing connector that changes diameter from round to square.

3. The water-cooled elbow for high-temperature titanium dioxide single-tube heat exchange as described in claim 1, characterized in that, The tilt angle of the heat dissipation plate is 25~45°.

4. The water-cooled elbow for high-temperature titanium dioxide single-tube heat exchange as described in claim 1, characterized in that, The outer arc wall at the reinforcing layer is detachably connected to the adjacent outer arc wall by a concave-convex fit connection, and the fit is sealed by welding.

5. The water-cooled elbow for high-temperature titanium dioxide single-tube heat exchange as described in claim 4, characterized in that, The outer arc wall of the reinforcing layer has bosses at both ends, and the adjacent outer arc wall ends have corresponding grooves.

6. The water-cooled elbow for high-temperature titanium dioxide single-tube heat exchange as described in claim 1, characterized in that, The reinforcing layer is a zirconium-aluminum composite ceramic layer.

7. The water-cooled elbow for high-temperature titanium dioxide single-tube heat exchange as described in claim 1, characterized in that, The inner side of the outer arc wall of the material impact zone of the pipeline is provided with a dovetail groove, and the reinforcing layer is fixed in the dovetail groove.

8. The water-cooled elbow for high-temperature titanium dioxide single-tube heat exchange as described in claim 7, characterized in that, The reinforcing layer is fixed to the outer arc wall by a secondary adhesive bonding process.

9. The water-cooled elbow for high-temperature titanium dioxide single-tube heat exchange as described in claim 1, characterized in that, The water-cooled elbow also includes an online ultrasonic thickness gauge for measuring the thickness of the reinforcing layer and the pipe online.

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