Compressed air pretreatment device and deoiling purification system

Abstract

The utility model discloses a compressed air pretreatment device which is provided with a preheating air inlet, a preheating air outlet, a heat recovery air inlet and a heat recovery air outlet and comprises a low-temperature part and a high-temperature part, the high-temperature part is arranged behind the low-temperature part, and the preheating air inlet and the heat recovery air outlet are formed in the low-temperature part. The preheating air outlet and the heat recovery air inlet are formed in the high-temperature part. According to the utility model, the pretreatment process is completed twice, so that for the low-temperature part and the high-temperature part, the temperature difference of the compressed air in each part is greatly reduced. After the temperature difference is reduced, the situation that the heat exchanger is deformed or damaged due to the too large temperature difference can be avoided, and therefore the good heat exchange effect can be guaranteed. And meanwhile, the quality requirements on the low-temperature part and the high-temperature part are reduced, and the cost of the pretreatment device can be reduced. The utility model further provides a compressed air deoiling and purifying system comprising the compressed air pretreatment device.

Description

Technical Field

[0001] This utility model relates to a compressed air pretreatment device, specifically a compressed air pretreatment device for graded pretreatment of compressed air. Background Technology

[0002] Air is compressible; compressed air is air whose volume is reduced and pressure increased after being processed by an air compressor. Compressed air is an important power source. Compared with other energy sources, it has the following distinct characteristics: it is clear and transparent, easy to transport, has no special harmful properties, poses no fire hazard, is not afraid of overload, can work in many adverse environments, and is abundant and inexhaustible. Because compressed air often contains a certain amount of oil, oil removal treatment is currently performed to improve its quality.

[0003] For example, Chinese patent document CN218358473U discloses a compressed air catalytic oxidation oil removal and purification device, including a base, a reaction tank, a heat exchanger, and an electrical control unit fixed on the base. The reaction tank is equipped with a heater on its exterior and includes a cylindrical body with a sealing gasket and a cover at the top. The upper part of the cylindrical body has an air inlet and an air outlet. An air outlet pipe is arranged axially along the inside of the cylindrical body, with its upper part connected to the air outlet. A catalyst is installed in the space between the outer wall of the air outlet pipe and the inner wall of the cylindrical body. The compressed air inlet of the heat exchanger is connected to a preheating inlet, and the compressed air outlet is connected to a heat recovery outlet. The preheating outlet of the heat exchanger is connected to the reaction tank inlet via an intermediate inlet pipe, and the heat recovery inlet is connected to the reaction tank outlet via an intermediate outlet pipe. This invention allows for convenient inspection and replacement of the catalyst, and ensures uniform catalyst temperature distribution within the reaction tank, thus improving the catalytic oxidation purification and oil removal effect.

[0004] In this prior art, a heat exchanger is set up to preheat the compressed air entering the reaction tank and recover the heat of the compressed air after purification and catalysis. However, in actual use, it has been found that the current heat exchangers all have different shortcomings. For example, plate heat exchangers are not suitable for high-temperature reaction conditions, and shell-and-tube heat exchangers will also have a large volume when the temperature difference is large. Therefore, they are not suitable for standard general-purpose products. This leads to the problem that the existing heat exchangers generally have unsatisfactory heat exchange effects. Utility Model Content

[0005] To address the technical problem of unsatisfactory heat exchange effect in existing heat exchangers, this utility model provides a compressed air pretreatment device. The pretreatment device is equipped with a preheating inlet, a preheating outlet, a heat recovery inlet, and a heat recovery outlet. The pretreatment device includes a low-temperature section and a high-temperature section, with the high-temperature section located after the low-temperature section. The preheating inlet and heat recovery outlet are located in the low-temperature section, while the preheating outlet and heat recovery inlet are located in the high-temperature section.

[0006] Currently, commonly used heat exchangers include plate heat exchangers and shell-and-tube heat exchangers. Plate heat exchangers have high heat exchange efficiency and a small volume for the same heat exchange area, but their pressure resistance is low, making them unsuitable for high-temperature and high-pressure reaction conditions. Furthermore, the plates of plate heat exchangers are prone to deformation or damage under excessive temperature differences. On the other hand, due to their structural limitations, shell-and-tube heat exchangers have a small heat exchange area per unit volume, resulting in a large volume for conditions involving large air volumes and high temperature differences.

[0007] In this design, the pretreatment unit is divided into a low-temperature section and a high-temperature section. Compressed air undergoes treatment in the low-temperature section before entering the high-temperature section for secondary treatment, thus completing the entire pretreatment process. Because the pretreatment process is completed in two stages, the temperature difference between the various parts of the compressed air in the low-temperature and high-temperature sections is significantly reduced. This reduced temperature difference prevents excessive temperature variations that could cause deformation or damage to the heat exchanger, ensuring good heat exchange performance. Simultaneously, the quality requirements for the low-temperature and high-temperature sections are lowered, and the cost of the pretreatment unit is also reduced.

[0008] Preferably, the low-temperature section is provided with a low-temperature air outlet, and the high-temperature section is provided with a high-temperature air inlet communicating with the low-temperature air outlet. In this design, the low-temperature compressed air is heated after being processed in the low-temperature section, and then enters the high-temperature section for secondary heating, resulting in a simple structure.

[0009] Preferably, a plate heat exchanger is used in the low-temperature section. Because the plates of a plate heat exchanger are thin, its pressure-bearing capacity is relatively low. Therefore, in this design, a plate heat exchanger is used in the low-temperature section to ensure high heat exchange efficiency and the normal operation of the plate heat exchanger.

[0010] Preferably, the cryogenic section uses a brazed plate heat exchanger. Using a brazed plate heat exchanger in this design for the cryogenic section allows for more efficient heat transfer and saves energy costs.

[0011] Preferably, the high-temperature section has a tube side and a shell side, with the high-temperature section air inlet located in the tube side and the heat recovery air inlet located in the shell side. In this design, the compressed air is heated in the tube side and cooled in the shell side after oil removal. It also enables the recovery of the compressed air's heat energy, which is then used to heat the compressed air entering the high-temperature section subsequently, thus achieving heat energy reuse and a simple structure.

[0012] Secondly, this utility model also provides a compressed air oil removal and purification system, including an oil removal device and the aforementioned compressed air pretreatment device, wherein the preheated air outlet is connected to the inlet of the oil removal device, and the heat recovery air inlet is connected to the outlet of the oil removal device.

[0013] Preferably, it also includes an external heater installed on the outer casing of the oil removal equipment. In this solution, using an external heater to heat the oil removal equipment ensures the normal operation of the oil removal process and has a simple structure.

[0014] Preferably, the high-temperature section uses a shell-and-tube heat exchanger. Since most oil removal equipment uses a tube structure, in this design, the shell-and-tube heat exchanger in the high-temperature section and the oil removal reactor are both tube structures. The same tube diameter can be used to achieve an organic combination of the shell-and-tube heat exchanger and the oil removal reactor in terms of structure. This can effectively save space and reduce heat loss during airflow.

[0015] This utility model has the following beneficial effects:

[0016] 1. In this invention, the pretreatment process is completed in two stages, thus significantly reducing the temperature difference between the low-temperature and high-temperature sections. This reduced temperature difference prevents deformation or damage to the heat exchanger caused by excessive temperature variations, ensuring optimal heat exchange performance. Simultaneously, the quality requirements for the low-temperature and high-temperature sections are lowered, and the cost of the pretreatment device is also reduced.

[0017] 2. In this utility model, after heat exchange in the high-temperature section using a shell-and-tube heat exchanger, the temperature of the compressed air is reduced. Therefore, the temperature of the compressed air entering the brazed plate heat exchanger is greatly reduced, and the heat exchange temperature difference of the brazed plate heat exchanger is also greatly reduced. Consequently, the operating temperature is also reduced, thereby increasing the operating pressure range of the brazed plate heat exchanger. The overall equipment can adapt to a greater operating pressure. This allows the advantages of both heat exchanger structures to be utilized: the shell-and-tube type can increase the temperature and pressure adaptability range by flexibly adjusting the materials, while the brazed plate heat exchanger has high heat exchange efficiency and a compact size. By integrating the shell-and-tube heat exchanger with the reactor to share the high-temperature working conditions, the brazed plate heat exchanger can increase the adaptable operating pressure range under low-temperature conditions. Thus, the overall equipment can adapt to a greater operating pressure to provide medium and high pressure oil-free compressed air to customers.

[0018] 3. In this utility model, after the temperature of the compressed air entering the brazed plate heat exchanger decreases, the volumetric flow rate under operating conditions also decreases, which can also reduce the pressure loss of the brazed plate heat exchanger to a certain extent.

[0019] 4. Due to the reduced operating temperature, the quality requirements for brazed plate heat exchangers can be appropriately lowered. Reliable domestic heat exchangers can be selected to replace imported heat exchangers, thus controlling both cost and delivery time. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the compressed air pretreatment device in an embodiment of the compressed air pretreatment device and oil removal and purification system of this utility model;

[0021] Figure 2 This is a schematic diagram of a compressed air oil removal and purification system. Detailed Implementation

[0022] The following detailed description illustrates the specific implementation method:

[0023] 1. Definition

[0024] Pretreatment: In this utility model, the pretreatment of compressed air refers to heating the compressed air before the oil removal operation and recovering and utilizing the heat in the compressed air after the oil removal operation.

[0025] Plate heat exchangers are a type of high-efficiency heat exchanger composed of a series of metal plates with a certain corrugated shape stacked together. Thin rectangular channels are formed between the various plates, through which heat exchange occurs.

[0026] Brazed plate heat exchangers are a new type of high-efficiency heat exchanger made by brazing a series of metal plates with a certain corrugated shape. Thin rectangular channels are formed between the various plates, through which heat exchange occurs.

[0027] Shell-and-tube heat exchangers, also known as tubular heat exchangers, are indirect heat exchangers that use the walls of tube bundles enclosed in a shell as the heat transfer surface. A shell-and-tube heat exchanger consists of a shell, heat transfer tube bundles, tube sheets, baffles, and tube boxes. The shell is typically cylindrical, containing the tube bundles, which are fixed at both ends to the tube sheets. The two fluids exchanging heat are called the tube-side fluid and the shell-side fluid; one flows inside the tubes.

[0028] Tube side: In shell-and-tube heat exchangers, the tube side typically refers to the working medium, such as fluid or gas, that flows through the tubes or pipes. These tubes or pipes are usually enclosed within the shell of the heat exchanger, forming the main channels for heat exchange.

[0029] Shell side: In a shell-and-tube heat exchanger, the shell side refers to the space inside the heat exchanger shell. This space is usually designed to allow another working medium to flow and exchange heat with the medium in the tube side.

[0030] Oil removal equipment: Equipment used to remove oil from compressed air. In this embodiment, the oil in the compressed air is converted into carbon dioxide and water through catalytic oxidation to achieve the purpose of oil removal; the catalytic oxidation reaction has temperature requirements, therefore a high-temperature reaction environment needs to be established in the system.

[0031] Operating volume: refers to the volume of gas under actual working conditions.

[0032] 2. The reference numerals in the accompanying drawings include: low temperature section 1, preheating air inlet 11, low temperature section air outlet 12, low temperature section air inlet 13, heat recovery air outlet 14, high temperature section 2, heat recovery air inlet 21, high temperature section air outlet 22, oil removal equipment 3, and external heater 4.

[0033] The basic implementation examples are as follows: Figure 1 and Figure 2 As shown: Compressed air pretreatment device, the pretreatment device includes a preheating inlet 11, a preheating outlet, a heat recovery inlet 21 and a heat recovery outlet 14. The pretreatment device includes a low temperature section 1 and a high temperature section 2. The high temperature section 2 is placed after the low temperature section 1. The preheating inlet 11 and the heat recovery outlet 14 are located in the low temperature section 1, and the preheating outlet and the heat recovery inlet 21 are located in the high temperature section 2.

[0034] This embodiment also provides a compressed air oil removal and purification system, including an oil removal device 3 and the aforementioned compressed air pretreatment device. The inlet of the oil removal device 3 is connected to the preheated air outlet, and the heat recovery air inlet 21 is connected to the outlet of the oil removal device 3. The connection between the oil removal device 3 and the high-temperature section can be achieved by flange connection, chuck connection, or direct welding of the upper and lower tubes together.

[0035] In this embodiment, the low-temperature section 1 adopts a brazed plate heat exchanger, and the high-temperature section 2 adopts a shell-and-tube heat exchanger. The preheating inlet 11 and the heat recovery outlet 14 are respectively located on both sides of the same end of the low-temperature section 1. At the other end of the low-temperature section 1, there are a low-temperature outlet 12 and a low-temperature inlet 13, wherein the low-temperature outlet 12 and the preheating inlet 11 are located on the same side, and the low-temperature inlet 13 and the heat recovery outlet 14 are located on the same side.

[0036] A high-temperature section air inlet is provided at one end of the tube side of the high-temperature section 2, which is connected to the low-temperature section air outlet 12. A preheating air outlet is provided at the other end of the tube side. A heat recovery air inlet 21 is provided at one end of the shell side of the high-temperature section 2. The heat recovery air inlet 21 and the preheating air outlet are located at the same end. A high-temperature section air outlet 22 is provided at the other end of the shell side. The high-temperature section air outlet 22 and the high-temperature section air inlet are located at the same end. The high-temperature section air outlet 22 is connected to the low-temperature section air inlet 13 of the low-temperature section 1.

[0037] The oil removal device 3 can be selected according to the oil removal method adopted. In this embodiment, the oil in the compressed air is converted into carbon dioxide and water by catalytic oxidation to achieve the purpose of oil removal. The outer shell of the oil removal device 3 is equipped with an external heater 4.

[0038] The specific implementation process is as follows: During use, the compressed air to be degreased enters the low-temperature section 1 through the preheating inlet 11, and then flows out from the low-temperature section outlet 12 on the same side. At this time, the compressed air is heated once by the low-temperature section 1, and its temperature rises. Then, the compressed air enters the tube of the high-temperature section 2 through the high-temperature section inlet, and then flows out from the preheating outlet. At this time, the compressed air is heated twice by the high-temperature section 2, and its temperature is greatly increased.

[0039] High-temperature compressed air enters the oil removal device 3. After the oil removal device 3 removes oil from the compressed air, the compressed air flows out of the oil removal device 3 and then flows into the shell side of the high-temperature section 2 from the heat recovery inlet 21. Subsequently, it flows out from the high-temperature section outlet 22. During this process, the high-temperature compressed air achieves heat exchange in the high-temperature section 2, heating the compressed air in the tube side and reducing the temperature of the compressed air in the shell side, thus achieving heat recovery.

[0040] After being cooled once, the compressed air flows out of the high-temperature section outlet 22 and then flows into the low-temperature section 1 through the low-temperature section inlet 13. It then flows out from the heat recovery outlet 14. During this process, the compressed air undergoes a second heat exchange in the low-temperature section 1. The temperature of the compressed air to be degreased rises, while the temperature of the degreased compressed air decreases. Finally, it flows out from the heat recovery outlet 14 and enters the subsequent processing equipment.

[0041] In this embodiment, the low-temperature section 1 uses a high-efficiency stainless steel brazed plate heat exchanger, and the high-temperature section 2 uses a shell-and-tube heat exchanger. The inlet air temperature at the preheating inlet 11 is tested at 20°C, and the compressed air temperature of each part is measured. The measurement results are as follows:

[0042] 1. Low-Temperature Section 1: Preheating inlet 11 temperature 20℃, low-temperature section outlet 12 temperature 140℃, low-temperature section inlet 13 temperature 158℃, heat recovery outlet 14 temperature 38℃; the overall temperature of low-temperature section 1 is controlled at around 150℃, which can avoid a significant decrease in allowable stress caused by high temperature and improve the overall pressure resistance performance. Allowable stress refers to the maximum stress value that a part or component is allowed to withstand in mechanical design or engineering structural design.

[0043] 2. High-temperature section 2: The inlet temperature of the high-temperature section is 140℃, the outlet temperature of the preheating section is 210℃, the inlet temperature of the heat recovery section 21 is 228℃, and the outlet temperature of the high-temperature section 22 is 158℃. The high-temperature conditions are all handled by the high-temperature section 2, and the temperature difference is controlled. The heat exchange load is not large, and the size of the high-temperature section 2 is controlled.

[0044] The above descriptions are merely embodiments of this utility model. Commonly known structures and characteristics are not described in detail here. Those skilled in the art are aware of all common technical knowledge in the field prior to the application date or priority date, are knowledgeable of all existing technologies in that field, and possess the ability to apply conventional experimental methods prior to that date. Therefore, those skilled in the art can, based on the guidance provided in this application, improve and implement this solution in conjunction with their own capabilities. Typical known structures or methods should not be obstacles for those skilled in the art to implement this application. It should be noted that those skilled in the art can make several modifications and improvements without departing from the structure of this utility model. These modifications and improvements should also be considered within the scope of protection of this utility model, and will not affect the effectiveness of the implementation of this utility model or the practicality of the patent. The scope of protection claimed in this application should be determined by the content of its claims, and the specific embodiments described in the specification can be used to interpret the content of the claims.

Claims

1. A compressed air pretreatment device, wherein the pretreatment device is provided with a preheating inlet, a preheating outlet, a heat recovery inlet, and a heat recovery outlet, characterized in that: The pretreatment device includes a low-temperature section and a high-temperature section, with the high-temperature section located after the low-temperature section. The preheating air inlet and the heat recovery air outlet are located in the low-temperature section, while the preheating air outlet and the heat recovery air inlet are located in the high-temperature section.

2. The compressed air pretreatment device according to claim 1, characterized in that: The low-temperature section is provided with a low-temperature section air outlet, and the high-temperature section is provided with a high-temperature section air inlet that communicates with the low-temperature section air outlet.

3. The compressed air pretreatment device according to claim 2, characterized in that: The low-temperature section uses a plate heat exchanger.

4. The compressed air pretreatment device according to claim 3, characterized in that: The cryogenic section employs a brazed plate heat exchanger.

5. The compressed air pretreatment device according to any one of claims 2-4, characterized in that: The high-temperature section has a tube side and a shell side, the air inlet of the high-temperature section is located in the tube side, and the air inlet of the heat recovery section is located in the shell side.

6. A compressed air oil removal and purification system, including an oil removal device, characterized in that: It also includes the compressed air pretreatment device as described in any one of claims 1-5, wherein the preheated air outlet is connected to the inlet of the oil removal device, and the heat recovery air inlet is connected to the outlet of the oil removal device.

7. The compressed air oil removal and purification system according to claim 6, characterized in that: It also includes an external heater mounted on the housing of the degreasing equipment.

8. The compressed air oil removal and purification system according to claim 7, characterized in that: The high-temperature section uses a shell-and-tube heat exchanger.

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