A uniform distribution guide plate arranged at a gas-liquid two-phase inlet of a styrene heat exchanger

Abstract

The technical scheme of the utility model discloses a uniform distribution flow guide plate arranged at the gas-liquid two-phase inlet of a styrene heat exchanger, the heat exchanger is provided with a shell, the uniform distribution flow guide plate is fixed at the shell medium inlet, the main body of the uniform distribution flow guide plate is in the shape of an eggshell curve, the maximum diameter of the end of the eggshell curve is less than the diameter of the shell medium inlet, array arrangement holes are arranged on the eggshell curve, an outer edge plate is fixed at the end of the eggshell curve, a connecting column is fixed on the outer edge plate, and one end of the connecting column, which is away from the outer edge plate, is fixed on the inner wall of the shell at the periphery of the shell medium inlet. Advantageous effects: the eggshell curve of the uniform distribution flow guide plate converts concentrated impact force into distributed load, which can effectively relieve stress concentration caused by fluid impact on the surface of the tube bundle. The array arrangement holes promote uniform dispersion of liquid, reduce local impact frequency, guide gas phase components to diffuse to the periphery, and avoid cavitation corrosion caused by concentrated rupture of bubbles on the first row of tube walls.

Description

Technical Field

[0001] This utility model relates to the improvement of heat exchanger technology, specifically to a gas-liquid two-phase inlet anti-impact guiding structure for heat exchangers in large styrene plants. Background Technology

[0002] In heat exchangers of large styrene plants, a mixture of ethylbenzene and water often enters the heat exchanger as a gas-liquid two-phase flow. This two-phase flow, due to high velocity, phase change, and pressure fluctuations in the heat exchanger inlet region, significantly impacts the surface of the heat transfer tube bundle, specifically manifesting in the following two problems:

[0003] (1) Tube bundle impact wear: The inlet fluid velocity is as high as 20 m / s, which directly impacts the first row of tube bundles, resulting in local stress concentration on the tube wall. Under long-term operation, fatigue cracks or corrosion perforation are likely to occur. The gas phase components on the surface of the high-temperature tube bundle break due to the sudden pressure drop, generating cavitation effect, which further aggravates the peeling of the tube wall material and significantly shortens the equipment life;

[0004] (2) Uneven flow distribution: The gas-liquid two-phase flow separates due to inertia in the inlet area, forming a "layered flow" and reducing the heat transfer efficiency. Due to the attenuation of upstream kinetic energy, the flow velocity distribution of the rear tube bundle is uneven, resulting in an increase in local thermal resistance and a decrease in the overall heat transfer coefficient.

[0005] Adding baffles to buffer the impact force is one method, but the flat plate structure is simple, has poor structural symmetry, and its rigid structure cannot adapt to changes in flow velocity, and cannot effectively disperse the impact energy. The fluid mainly enters the tube bundle from both sides of the baffle, resulting in an increase in the local flow velocity of the first row of tube bundles. Utility Model Content

[0006] To overcome the above-mentioned defects in the prior art, the present invention proposes a uniformly distributed guide plate installed at the gas-liquid two-phase inlet of a styrene heat exchanger.

[0007] The technical solution of this utility model is as follows: A uniformly distributed guide plate is provided at the gas-liquid two-phase inlet of a styrene heat exchanger. The heat exchanger has a shell, and the uniformly distributed guide plate is fixed at the medium inlet of the shell. The main body of the uniformly distributed guide plate is an egg-shaped curved surface. The maximum diameter of the end of the egg-shaped curved surface is smaller than the diameter of the medium inlet of the shell. An array of holes is provided on the egg-shaped curved surface. An outer edge plate is fixed at the end of the egg-shaped curved surface. A connecting column is fixed on the outer edge plate. The end of the connecting column away from the outer edge plate is fixed to the inner wall of the shell outside the medium inlet of the shell.

[0008] Preferably, the diameter of the array of holes is 40 mm.

[0009] Preferably, the inner wall surface of the evenly distributed guide plate body is provided with raised ribs, and the raised ribs are connected to each other to form a rib network.

[0010] Preferably, the cross-section of the rib is semi-circular and the height is 8-10 mm.

[0011] The eggshell-shaped curved surface, outer edge plate, and ribs are integrally formed, and the connecting column is welded to the outer edge plate and the inner wall of the shell.

[0012] The beneficial effects of this invention are as follows: the uniformly distributed guide plates effectively guide the flow of the gas-liquid two-phase flow, and the egg-shaped curved surface transforms the concentrated impact force into a distributed load, effectively alleviating the stress concentration caused by fluid impact on the tube bundle surface. The arrayed holes promote uniform liquid dispersion, reduce the local impact frequency, guide the gas phase components to diffuse outwards, and avoid cavitation corrosion caused by concentrated bubble rupture on the first row of tube walls. This patent has significant advantages in solving the impact problem of gas-liquid two-phase flow on heat exchanger tube bundles and has important practical application value. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of the structure of this utility model;

[0014] Figure 2 This is a diagram showing the velocity isosurface distribution at the inlet of a heat exchanger with and without uniformly distributed guide vanes.

[0015] Figure 3 This is a schematic diagram of the inner wall surface of the evenly distributed guide vanes;

[0016] 1-Evenly distributed guide plate, 2-Arrayed arrangement of holes, 3-Connecting column, 4-Protruding rib, 5-Shell. Detailed Implementation

[0017] like Figure 1 This is a heat exchanger for a large styrene plant. The heat exchanger has a shell and is currently the most widely used type of styrene heat exchanger. A uniformly distributed guide plate 1 is fixed at the gas-liquid two-phase inlet of the shell medium. The guide plate 1 is a curved, egg-shell-shaped surface. The maximum diameter of the end of the egg-shell-shaped surface is smaller than the diameter of the shell medium inlet. An array of holes 2 with a diameter of 40 mm are arranged on the egg-shell-shaped surface. An outer edge plate is fixed to the end of the egg-shell-shaped surface, and a connecting column 3 is fixed to the outer edge plate. The end of the connecting column 3 furthest from the outer edge plate is fixed to the inner wall of the shell surrounding the shell medium inlet.

[0018] Holes are made on the eggshell-shaped curved surface. To increase impact resistance, ribs 4 are provided on the inner wall of the evenly distributed guide plate 1. The ribs 4 are connected to each other to form a rib mesh. The cross section of the ribs 4 is semi-circular and the height is 8-10 mm.

[0019] For the uniformly distributed guide plate 1, since its shape is not a standard circle, the egg-shaped curved surface, outer edge plate, and protruding ribs 4 are integrally formed for easy processing and molding, for example, by using a hot pressing process for sheet metal. The connecting column 3 is welded to the outer edge plate and the inner wall of the shell.

[0020] Figure 2As shown, the velocity isosurface distribution at the heat exchanger inlet is compared before and after the addition of a uniformly distributed baffle. The left figure shows the flow without a uniformly distributed baffle, where the fluid enters in a hemispherical distribution at 15 m / s, then decreases to 10 m / s, and the velocity distribution begins to show an oblate spheroid shape, finally impacting the first layer of pipe walls at a high speed of 20 m / s. The right figure shows the flow with a uniformly distributed baffle. The hemispherical isosurface with a velocity of 15 m / s is slowed down by the baffle, forming several 10 m / s flow streams that directly impact the tubes. No high-speed impact area is formed on the surface of the first layer of heat exchange tubes, indicating that the uniformly distributed baffle effectively reduces the direct scouring of the inlet fluid on the tube bundle. However, the fluid blocked by the uniformly distributed baffle will accelerate to 20 m / s along the baffle. This part of the fluid will not directly impact the tube bundle but will be guided and diverted, forming a backflow, and its kinetic energy will be gradually consumed.

[0021] Under the action of the uniformly distributed guide plate 1, the non-uniformity of the flow of the medium outside the pipe is reduced, which is 3% lower than that of the traditional multi-unit heat exchanger of styrene plant.

Claims

1. A uniformly distributed guide vane installed at the gas-liquid two-phase inlet of a styrene heat exchanger, the heat exchanger having a shell, characterized in that: A uniformly distributed guide plate (1) is fixed at the medium inlet of the shell. The main body of the uniformly distributed guide plate (1) is an egg-shaped curved surface. The maximum diameter of the end of the egg-shaped curved surface is smaller than the diameter of the medium inlet of the shell. An array of holes (2) is set on the egg-shaped curved surface. An outer edge plate is fixed at the end of the egg-shaped curved surface. A connecting column (3) is fixed on the outer edge plate. The end of the connecting column (3) away from the outer edge plate is fixed to the inner wall of the shell outside the medium inlet of the shell.

2. A uniformly distributed guide vane installed at the gas-liquid two-phase inlet of a styrene heat exchanger according to claim 1, characterized in that: The aperture of the array arrangement hole (2) is 40 mm.

3. The uniformly distributed guide vane installed at the gas-liquid two-phase inlet of a styrene heat exchanger according to claim 1, characterized in that: The inner wall of the uniformly distributed guide plate (1) is provided with ribs (4), and the ribs (4) are connected to each other to form a rib network.

4. A uniformly distributed guide vane installed at the gas-liquid two-phase inlet of a styrene heat exchanger according to claim 3, characterized in that: The cross section of the rib (4) is semi-circular, and the height is 8-10 mm.

5. A uniformly distributed guide vane installed at the gas-liquid two-phase inlet of a styrene heat exchanger according to claim 3 or 4, characterized in that: The eggshell-shaped curved surface, outer edge plate, and rib (4) are integrally formed, and the connecting column (3) is welded to the outer edge plate and the inner wall of the shell.

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