Energy-saving heat exchanger for rectifying tower

Abstract

The energy-saving heat exchanger comprises a separator, the separator comprises a barrel, a feeding port, a gas outlet and a liquid outlet are formed in the barrel, the feeding port is formed in the tangential direction of the barrel, the gas outlet is located in the top of the barrel, and the liquid outlet is located in the bottom of the barrel; the evaporator is communicated with a liquid outlet in the bottom of the separator and is used for heating the liquid output by the separator to generate steam; the condenser is communicated with the evaporator and is used for condensing the steam output by the evaporator into liquid; the separator further comprises at least one separation unit, and the separation unit is arranged in the barrel and used for conducting auxiliary separation on an entered gas-liquid mixture which spirally moves along the inner wall of the barrel. The device has the effect of effectively reducing gas-liquid entrainment.

Description

Technical Field

[0001] This application relates to the technical field of heat exchangers, and in particular to an energy-saving heat exchanger for distillation columns. Background Technology

[0002] Distillation columns, as important chemical separation equipment, are widely used in many fields such as petrochemicals, pharmaceuticals, and food and beverage. Their core function is to achieve efficient separation of components in a mixture through phase change. Currently, typical distillation column equipment usually includes key units such as separators, evaporators, and condensers.

[0003] The separator utilizes the centrifugal force generated when a gas-liquid mixture enters the cylinder through a tangential feed inlet to achieve efficient separation. The material moves in a spiral motion along the cylinder wall; the liquid is thrown against the wall and settles due to centrifugal force, while the gas rises. The separated liquid flows into the evaporator, while the gas exits from the top outlet. The evaporator uses heat transfer oil to heat the liquid in the tube side, causing it to evaporate into steam. Some of the incompletely evaporated liquid can be re-entered into the evaporator through the reflux port for reheating. The condenser uses cooling water to cool the steam in the tube side, causing it to condense into liquid, which is then discharged through a liquid collector.

[0004] Existing separators primarily rely on centrifugal force for separation. When the properties of the feed material (such as density, viscosity, surface tension), flow rate, or state (such as gas-liquid ratio, droplet size) change, centrifugal force may be insufficient to achieve efficient separation. Gas-liquid entrainment (i.e., liquid being carried away by the rising airflow) or insufficient liquid settling may occur, resulting in gas entrainment in the liquid entering the evaporator, or insufficient liquid volume entering the evaporator, leading to problems such as low evaporation efficiency, increased energy consumption, and low separation accuracy. Summary of the Invention

[0005] In order to overcome the technical problems described in the prior art, this application provides an energy-saving heat exchanger for a distillation column.

[0006] The energy-saving heat exchanger for distillation columns provided in this application adopts the following technical solution: An energy-saving heat exchanger for a distillation column, comprising: A separator includes a cylinder with a feed inlet, a gas outlet, and a liquid outlet. The feed inlet is located along the tangential direction of the cylinder, the gas outlet is located at the top of the cylinder, and the liquid outlet is located at the bottom of the cylinder. An evaporator, connected to the liquid outlet at the bottom of the separator, is used to heat the liquid output from the separator to generate steam; A condenser, connected to an evaporator, is used to condense the vapor output from the evaporator into a liquid; The separator further includes at least one separation unit, which is located inside the cylinder and is used to assist in the separation of the gas-liquid mixture that enters and spirals along the inner wall of the cylinder.

[0007] Furthermore, the separation unit includes multiple sets of baffles spaced apart along the axial direction of the cylinder. The multiple sets of baffles form at least two independent blocking layers inside the cylinder, and a channel for the gas-liquid mixture to flow downward is left between two adjacent blocking layers.

[0008] Furthermore, the barrier layer includes at least two baffles spaced apart from each other.

[0009] Furthermore, an overflow port is provided between the baffle and the inner wall of the cylinder to allow liquid to flow downwards.

[0010] Furthermore, the separation unit includes swirl blades disposed inside the cylinder.

[0011] Furthermore, the evaporator is equipped with a cleaning mechanism for cleaning the heat exchange tube bundle.

[0012] Furthermore, the cleaning mechanism includes a pulse backwashing device disposed at the end of the heat exchange tube bundle.

[0013] Furthermore, the cleaning mechanism includes a flexible scraping device disposed at the end of the heat exchange tube bundle.

[0014] Furthermore, the inner wall of the heat exchange tube bundle is coated with a low surface energy coating.

[0015] In summary, the beneficial technical effects of this application are as follows: By incorporating a separation unit within the separator's cylinder, this application assists in the separation of the gas-liquid mixture that spirals along the inner wall of the cylinder. This overcomes the performance degradation problem of traditional centrifugal separation when material properties change, maintaining high separation accuracy even under varying operating conditions and effectively reducing gas-liquid entrainment. The purer liquid entering the evaporator reduces the heat transfer area occupied by the gas, improving the evaporator's efficiency and thus lowering the demand for the heat transfer oil system, achieving indirect energy savings. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the overall structure of an embodiment of this application.

[0017] Figure 2 This is a schematic diagram of the structure of the cylinder, feed inlet, gas outlet and liquid outlet in the embodiments of this application.

[0018] Figure 3 This is a cross-sectional structural diagram of the cylinder, feed inlet, gas outlet, liquid outlet, and baffle in the embodiments of this application.

[0019] Figure 4 This is a schematic diagram of the structure of the cylinder, liquid outlet, baffle, channel and overflow port in the embodiments of this application.

[0020] Figure 5 This is a cross-sectional structural diagram of the cylinder, gas outlet, liquid outlet, and swirl blades in an embodiment of this application.

[0021] Figure 6 This is a cross-sectional structural diagram of the evaporator in an embodiment of this application.

[0022] Reference numerals in the attached diagram: 1. Separator; 2. Cylinder; 3. Inlet; 4. Gas outlet; 5. Liquid outlet; 6. Evaporator; 61. Shell; 62. Heat exchange tube bundle; 63. Baffle; 64. Support; 65. Tube box; 7. Condenser; 8. Baffle; 9. Channel; 10. Overflow port; 11. Swirl vanes; 12. Cleaning mechanism; 13. Heat transfer oil outlet; 14. Heat transfer oil inlet; 15. Steam outlet; 16. Liquid inlet. Detailed Implementation

[0023] The technical solutions of this application will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this application. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0024] This application discloses an energy-saving heat exchanger for a distillation column. (Refer to...) Figure 1 and Figure 2 An energy-saving heat exchanger for a distillation column includes an evaporator 6, a separator 1, and a condenser 7 arranged sequentially from bottom to top. The separator 1 includes a cylindrical body 2 with a feed inlet 3 tangentially arranged on it. The cylindrical body 2 has a gas outlet 4 at the top and a liquid outlet 5 at the bottom. During operation, the gas-liquid mixture enters through the tangential feed inlet 3, and centrifugal force is used to achieve efficient gas-liquid separation. The gas-liquid mixture spirals downwards along the inner wall of the cylindrical body 2. The liquid is thrown against the wall and settles under centrifugal force, avoiding interference from the rising airflow to the settled liquid. The separated liquid is discharged downwards through the liquid outlet 5, while the gas is discharged from the gas outlet 4 at the top. The evaporator 6 is connected to the liquid outlet 5 at the bottom of the separator 1 and is used to heat the liquid output from the separator 1 to generate steam. The condenser 7 is connected to the evaporator 6 and is used to condense the steam output from the evaporator 6 into liquid.

[0025] Separator 1 relies on centrifugal force for separation. While this avoids interference from the rising airflow on the settling liquid, changes in the composition, concentration, temperature, and pressure of the feed can alter the physical properties of the gas-liquid mixture, such as density, viscosity, and surface tension. This can lead to insufficient centrifugal force for effective separation within separator 1, or liquid entrainment by the airflow, resulting in a "spraying" phenomenon. This reduces separation efficiency, affects the purity of the liquid entering evaporator 6, and may even cause coking or blockage in evaporator 6. Therefore, to improve the gas-liquid separation efficiency in separator 1, refer to... Figure 2 , Figure 3 , Figure 4 and Figure 5 A separation unit is installed inside the cylinder 2, which adds auxiliary separation mechanisms such as "inertial impact" and "gravitational settling" to the separator 1 in addition to centrifugal force. These mechanisms can provide more effective phase separation for gas-liquid mixtures with different characteristics under different operating conditions, reduce gas-liquid entrainment, and improve separation accuracy.

[0026] Reference Figure 3 and Figure 4 In one feasible embodiment, the separation unit is configured as multiple sets of baffles 8 spaced apart along the axial direction of the cylinder 2. The multiple sets of baffles 8 are fixed vertically and vertically on the inner wall of the cylinder 2, forming at least two independent blocking layers within the cylinder 2. Each set of baffles 8 has at least two baffles. In this embodiment, there are two sets of baffles 8, with three baffles 8 in the same set. The three baffles 8 in the same set are evenly distributed circumferentially on the inner wall of the cylinder 2. The three baffles 8 in the two sets are staggered, meaning that the projections of the six baffles 8 do not overlap vertically, thus forming a channel 9 between the upper and lower blocking layers for the gas-liquid mixture to flow downwards. This staggered distribution can guide the gas-liquid mixture to undergo multiple changes in direction and collisions during its downward movement. In addition, an overflow port 10 is provided between the baffles 8 and the inner wall of the cylinder 2 for the liquid to flow downwards. The overflow port 10 allows gas to pass under high pressure or allows liquid to flow downwards along the cylinder wall, while preventing the baffles 8 from completely blocking the channel 9, which helps prevent scaling or blockage.

[0027] During operation, the gas-liquid mixture entering tangentially through inlet 3 spirals downwards within cylinder 2. Under centrifugal force, the liquid phase tends to approach the inner wall of cylinder 2. At this point, the staggered baffles 8 physically block and guide the fluid, forcing droplets to collide with the baffles 8, the inner wall of cylinder 2, and other droplets, promoting droplet coalescence (from small droplets to large droplets) and accelerating their settling. This multi-stage collision and guidance effect significantly enhances the gas-liquid separation process, overcoming the performance degradation problem of traditional centrifugal separation when material properties change. Even under varying operating conditions, it maintains high separation accuracy and effectively reduces gas-liquid entrainment. The purer liquid entering evaporator 6 reduces the heat transfer area occupied by gas, improving the efficiency of evaporator 6 and thus reducing the demand for the heat transfer oil system, achieving indirect energy savings.

[0028] Reference Figure 5 In another feasible embodiment, the separation unit is configured with swirl blades 11 to enhance rotational momentum, further increase centrifugal force, and assist in droplet coalescence and movement towards the wall. To further improve the separation efficiency of separator 1, the schemes in the above two embodiments can be implemented individually or in combination.

[0029] Reference Figure 6 The evaporator 6 adopts a shell-and-tube heat exchanger structure, including a shell 61, a heat exchange tube bundle 62, and multiple baffles 63. The heat exchange tube bundle 62 is stably supported inside the shell 61 by the multiple baffles 63. One side of the shell 61 has a heat transfer oil inlet 14 for entering the heat transfer oil, and the other side has a heat transfer oil outlet 13 for flowing out the heat transfer oil. A tube box 65 is provided at one end inside the shell 61. The tube box 65 is not connected to the chamber inside the shell 61. The heat exchange tube bundle 62 is U-shaped, and both ends of its tubes are inserted into the tube box 65. The tube box 65 has a liquid inlet 16 at the bottom and a steam outlet 15 at the top. The liquid inlet 16 is connected to the liquid outlet 5 at the bottom of the separator 1, allowing the liquid separated by the separator 1 to enter the heat exchange tube bundle 62 through one port. The liquid then flows into the shell 61 along with the heat exchange tube bundle 62, and finally flows out from the other port of the heat exchange tube bundle 62 and re-enters the tube box 65. During the liquid flow, the heat transfer oil in the shell 61 heats the liquid flowing through the heat exchange tube bundle 62, causing the liquid to evaporate and generate steam. The steam flows into the tube box 65 along with the liquid and exits from the steam outlet 15. Some of the unevaporated liquid continues to enter the heat exchange tube bundle 62 along with the liquid entering through the liquid inlet 16 for further evaporation.

[0030] Considering that the inner wall of the heat exchange tube bundle 62 is in direct contact with the material to be processed during the distillation process, and that scaling easily forms on the inner wall of the heat exchange tube bundle 62 as the liquid flows through it, thus affecting the heat exchange efficiency, therefore, referring to... Figure 6A bracket 64 is installed inside the tube box 65, and a cleaning mechanism 12 for cleaning the inner wall of the heat exchange tube bundle 62 is provided on the bracket 64. In one feasible embodiment, the cleaning mechanism 12 is a pulse backflushing device, which is characterized by high temperature resistance, corrosion resistance, and water resistance. By aligning the pulse backflushing device with the opening of the heat exchange tube bundle 62, the pulse backflushing device can periodically inject high-pressure media (such as steam, compressed air, or cleaning fluid) into the tube, generating instantaneous high-speed shock waves to break up and flush away dirt, scale, or polymers adhering to the inner wall of the tube. In another feasible embodiment, the cleaning mechanism 12 is a telescopic flexible scraping device. Specifically, the flexible scraping device can be a spiral spring pipe brush, an electric universal flexible rod cleaner, an olive-shaped head spring drain cleaner, etc. This telescopic flexible scraping device is common in the field of pipe cleaning and will not be described in detail here. By extending the flexible scraping device into the heat exchange tube bundle 62 and driving the flexible scraping device to extend and retract, the flexible scraping device periodically scrapes the inner wall of the tube. In addition, coating the inner wall of the heat exchange tube bundle 62 with a low surface energy coating, such as a hydrophobic or oleophobic coating or a ceramic coating, can greatly reduce the accumulation of dirt and reduce the frequency and intensity of cleaning.

[0031] The implementation principle of an energy-saving heat exchanger for a distillation column according to an embodiment of this application is as follows: A gas-liquid mixture is fed into the separator 1 through the feed inlet 3. The gas-liquid mixture entering tangentially through the feed inlet 3 forms a spiral downward movement within the cylinder 2. Under the action of centrifugal force, the liquid phase tends to approach the inner wall of the cylinder 2. At this time, the staggered baffles 8 physically block and guide the fluid, forcing the droplets to collide with the baffles 8, the inner wall of the cylinder 2, and other droplets, promoting droplet coalescence, and flowing from the channel 9 to the liquid outlet 5. During the collision process, gas easily overflows from the liquid and is discharged upward through the gas outlet 4.

[0032] The liquid flowing out of the liquid outlet 5 on the separator 1 flows into the heat exchange tube bundle 62 through the liquid inlet 16 on the evaporator 6. At this time, the heat transfer oil in the shell 61 can heat the liquid flowing through the heat exchange tube bundle 62, so that the liquid is evaporated to generate steam. The steam flows into the tube box 65 along with the liquid and flows out from the steam outlet 15. Meanwhile, some of the unevaporated liquid continues to enter the heat exchange tube bundle 62 again along with the liquid entering from the liquid inlet 16 for evaporation.

[0033] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. An energy-saving heat exchanger for a distillation column, characterized in that, include The separator (1) includes a cylinder (2), which is provided with a feed inlet (3), a gas outlet (4) and a liquid outlet (5). The feed inlet (3) is arranged along the tangential direction of the cylinder (2), the gas outlet (4) is located at the top of the cylinder (2), and the liquid outlet (5) is located at the bottom of the cylinder (2). Evaporator (6) is connected to the liquid outlet (5) at the bottom of separator (1) and is used to heat the liquid output from separator (1) to generate steam; The condenser (7) is connected to the evaporator (6) and is used to condense the steam output from the evaporator (6) into a liquid; The separator (1) further includes at least one separation unit, which is disposed inside the cylinder (2) and is used to perform auxiliary separation of the gas-liquid mixture that enters and moves spirally along the inner wall of the cylinder (2).

2. The energy-saving heat exchanger for a distillation column according to claim 1, characterized in that, The separation unit includes multiple sets of baffles (8) spaced apart along the axial direction of the cylinder (2). The multiple sets of baffles (8) form at least two independent blocking layers in the cylinder (2), and a channel (9) is left between two adjacent blocking layers for the gas-liquid mixture to flow downward.

3. An energy-saving heat exchanger for a distillation column according to claim 2, characterized in that, The barrier layer includes at least two baffles (8) spaced apart from each other.

4. An energy-saving heat exchanger for a distillation column according to claim 2, characterized in that, An overflow port (10) is provided between the baffle (8) and the inner wall of the cylinder (2) to allow liquid to flow downwards.

5. An energy-saving heat exchanger for a distillation column according to claim 1, characterized in that, The separation unit includes swirl blades (11) disposed inside the cylinder (2).

6. An energy-saving heat exchanger for a distillation column according to claim 1, characterized in that, The evaporator (6) is provided with a cleaning mechanism (12) for cleaning the heat exchange tube bundle (62).

7. An energy-saving heat exchanger for a distillation column according to claim 6, characterized in that, The cleaning mechanism (12) includes a pulse backwashing device disposed at the end of the heat exchange tube bundle (62).

8. An energy-saving heat exchanger for a distillation column according to any one of claims 6 or 7, characterized in that, The cleaning mechanism (12) includes a flexible scraping device disposed at the end of the heat exchange tube bundle (62).

9. An energy-saving heat exchanger for a distillation column according to claim 6, characterized in that, The inner wall of the heat exchange tube bundle (62) is coated with a low surface energy coating.

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