An air separation precooling system

Abstract

This application discloses an air separation precooling system, belonging to the field of metallurgical air separation oxygen production technology. It includes an air-cooled tower and a water-cooled tower. The water-cooled tower has an outlet, and the air-cooled tower has an inlet. The outlet is connected to a chiller unit via a first pipe. The chiller unit is connected to the inlet via a second pipe. A pipeline pump is installed on the first pipe, and a chilled water pump is installed on the second pipe. A first outlet valve is located on the first pipe between the chiller unit and the pipeline pump, and a second outlet valve is located on the second pipe between the chilled water pump and the air-cooled tower. This application increases the pressure of the cooling water entering the chiller unit by installing a pipeline pump on the first pipe. The flow rate of the cooling water entering the air-cooled tower is adjusted to a target value by adjusting the second outlet valve to meet the heat exchange requirements of the air-cooled tower. The pressure of the cooling water entering the chiller unit is adjusted by the first outlet valve to ensure that the pressure of the cooling water after pressurization by the pipeline pump does not exceed the operating pressure of the chiller unit.

Description

Technical Field

[0001] This application relates to the field of metallurgical air separation oxygen production technology, and in particular to an air separation precooling system. Background Technology

[0002] Air separation equipment, also known as air separation unit, is an indispensable device in modern industry, widely used in steel, chemical, and medical fields. The air cooling system is a key component of air separation equipment, playing a crucial role in the entire air separation process. The main functions of the air cooling system include improving air separation efficiency, protecting the air separation equipment, and enhancing the quality of the separated products. By pre-cooling the air entering the air separation unit to near its liquefaction temperature, the energy consumption required in subsequent separation processes can be significantly reduced, thereby lowering the overall operating costs. Furthermore, by lowering the air temperature, the air cooling system reduces the heat load on the equipment, thus extending its service life and reducing maintenance and replacement costs.

[0003] The main function of the air-cooling system is to cool the humid air after it has been pressurized by the air compressor, and to further remove particulate matter, some water-soluble substances (NH3, SO2, etc.), and other impurities from the air. The air-cooling tower is divided into upper and lower sections. The lower section uses circulating water for cooling, and the upper section uses chilled water for cooling. The temperature of the humid air is reduced by directly utilizing the heat exchange between the cooling water and chilled water and the humid air through contact with the random packing material. The cooling water is introduced from the lower part of the air-cooling tower, and the chilled water is introduced from the upper part. Both cooling water and chilled water originate from the circulating water pool. The cooling water is pressurized by the chilled water pump before being introduced, while the chilled water comes into contact with dry nitrogen in the air-cooling tower, utilizing the latent heat of vaporization of water to achieve cooling. The chilled water is then further cooled by the chiller unit, and then pressurized by the chilled water pump before being introduced. After heat exchange, the two are collected at the bottom of the air-cooling tower and returned to the circulating water network.

[0004] In air-cooled systems, the chiller unit operates at a lower pressure than the chilled water pump and is typically positioned before the pump. During the chilled water's journey through the chiller unit, the significant internal resistance can lead to insufficient pressure at the pump inlet. This can have a series of negative impacts on the entire system. First, insufficient pressure at the pump inlet slows the chilled water flow rate in the heat exchanger, reducing heat exchange efficiency and hindering the effective removal of heat from the air, resulting in an increase in the air temperature at the air-cooled tower outlet. Furthermore, insufficient inlet pressure can create negative pressure at the pump inlet, causing gases in the chilled water to precipitate and form bubbles. These bubbles burst in the high-pressure zone within the pump, causing cavitation, damaging the impeller and pump casing, and reducing the pump's lifespan. Summary of the Invention

[0005] The purpose of this application is to provide an air separation precooling system to solve the problem of insufficient inlet pressure of chilled water pumps in existing air-cooling systems.

[0006] To solve the above-mentioned technical problems, this application adopts the following technical solution:

[0007] This application provides an air separation precooling system, including an air-cooled tower and a water-cooled tower. The water-cooled tower has a water outlet, and the air-cooled tower has a water inlet. The water outlet is connected to a chiller unit through a first pipe, and the chiller unit is connected to the water inlet through a second pipe. A pipeline pump is installed on the first pipe, and a chilled water pump is installed on the second pipe. A first outlet valve is installed on the first pipe between the chiller unit and the pipeline pump, and a second outlet valve is installed on the second pipe between the chilled water pump and the air-cooled tower.

[0008] This solution increases the pressure of the cooling water entering the chiller unit by installing a pipeline pump on the first pipeline. The flow rate of the cooling water entering the air-cooled tower is adjusted to the target value by regulating the second outlet valve, thus meeting the heat exchange requirements of the air-cooled tower. Furthermore, to ensure that the pressure of the cooling water after pressurization by the pipeline pump does not exceed the operating pressure of the chiller unit, this solution includes a first outlet valve located between the chiller unit and the pipeline pump on the first pipeline. This first outlet valve allows for the regulation of the cooling water pressure entering the chiller unit. This solution, through pipeline pump pressurization, the first outlet valve, and the second outlet valve, effectively solves the problem of insufficient cooling water pressure in the air separation precooling system while meeting the operating pressure requirements of the chiller unit.

[0009] Optionally, a first pressure sensor is installed on the first pipeline between the chiller unit and the first outlet valve, and a second pressure sensor is installed on the second pipeline between the chiller unit and the chilled water pump.

[0010] This solution uses a first pressure sensor to monitor the outlet pressure of the pipeline pump, ensuring that the cooling water pressure after pressurization by the pipeline pump does not exceed the operating pressure of the chiller unit. This solution also uses a second pressure sensor to monitor the inlet pressure of the chilled water pump, ensuring that the cooling water pressure, affected by the chiller unit's resistance, meets the chilled water pump's pressure requirements.

[0011] Optionally, a flow sensor is installed in the second pipeline between the air-cooled tower and the second outlet valve.

[0012] This solution uses a flow sensor to monitor the flow rate of cooling water entering the air-cooled tower, ensuring that the flow rate meets the heat exchange requirements of the air-cooled tower. The flow sensor is installed on the second pipe between the air-cooled tower and the second outlet valve; adjusting the second outlet valve regulates the flow rate of cooling water entering the air-cooled tower.

[0013] Optionally, the second pipe located between the chilled water pump and the chiller unit is equipped with a second inlet valve.

[0014] Optionally, it also includes a PLC controller, which is connected to the pipeline pump, the chilled water pump, the first inlet valve, the first outlet valve and the second outlet valve respectively.

[0015] This solution uses a PLC controller to automate the control of the air separation precooling system, significantly improving system efficiency and reliability.

[0016] Optionally, the first pipeline is provided with a first inlet valve located between the water cooling tower and the pipeline pump.

[0017] Optionally, a bypass pipe is provided between the water cooling tower and the chiller unit, and a bypass valve is provided on the bypass pipe.

[0018] To avoid system shutdown and reduced production efficiency during pipeline pump maintenance, this solution also includes a bypass pipe connecting the water-cooled tower and the chiller unit. When pipeline pump maintenance is required, the first inlet valve and the first outlet valve can be closed, and the bypass valve can be opened to allow cooling water to flow into the chiller unit through the bypass pipe.

[0019] Compared with existing technologies, the beneficial effects achieved by this application are as follows: This application increases the pressure of the cooling water entering the chiller unit in the first pipeline by installing a pipeline pump on the first pipeline. The flow rate of the cooling water entering the air-cooled tower is adjusted to the target value by adjusting the second outlet valve to meet the heat exchange requirements of the air-cooled tower. Furthermore, this application provides a first outlet valve between the chiller unit and the pipeline pump in the first pipeline. This valve can regulate the pressure of the cooling water entering the chiller unit, thereby ensuring that the pressure of the cooling water after pressurization by the pipeline pump does not exceed the operating pressure of the chiller unit. This application effectively solves the problem of insufficient cooling water pressure in the air separation precooling system while meeting the operating pressure requirements of the chiller unit. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of this disclosure or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this disclosure. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 These are schematic diagrams of some embodiments provided in this application.

[0022] Explanation of reference numerals in the attached drawings: 1-Water-cooled tower; 2-Air-cooled tower; 3-Chiller unit; 4-Chiller water pump; 5-Pipeline pump; 6-First pipeline; 7-Second pipeline; 8-Bypass pipe; 61-First outlet valve; 62-First inlet valve; 63-First pressure sensor; 71-Second outlet valve; 72-Second inlet valve; 73-Second pressure sensor; 74-Flow sensor; 81-Bypass valve. Detailed Implementation

[0023] The technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this disclosure / application, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit this application or its application or use.

[0024] Example 1

[0025] This embodiment describes an air separation precooling system, referencing... Figure 1 The air separation precooling system in this embodiment includes an air-cooled tower 2 and a water-cooled tower 1. The water-cooled tower 1 has an outlet, and the air-cooled tower 2 has an inlet. The outlet is connected to a reciprocating chiller unit 3 via a first pipe 6. In this embodiment, the reciprocating chiller unit 3 operates at a pressure of 0.2 MPa. The reciprocating chiller unit 3 is connected to the inlet via a second pipe 7. A pipeline pump 5 is installed on the first pipe 6, and a chilled water pump 4 is installed on the second pipe 7. A first outlet valve 61 is installed on the first pipe 6 between the chiller unit 3 and the pipeline pump 5, and a second outlet valve 71 is installed on the second pipe 7 between the chilled water pump 4 and the air-cooled tower 2.

[0026] This embodiment increases the pressure of the cooling water entering the chiller unit 3 by installing a pipeline pump 5 on the first pipeline 6. The flow rate of the cooling water entering the air-cooled tower 2 is adjusted to the target value by adjusting the second outlet valve 71 to meet the heat exchange requirements of the air-cooled tower 2. Furthermore, to ensure that the pressure of the cooling water after pressurization by the pipeline pump 5 does not exceed the operating pressure of the reciprocating chiller unit 3, this embodiment installs a first outlet valve 61 between the chiller unit 3 and the pipeline pump 5 on the first pipeline 6. This first outlet valve 61 can regulate the pressure of the cooling water entering the chiller unit 3, keeping it within 0.2 MPa. This embodiment, through the pressurization by the pipeline pump 5, the first outlet valve 61, and the second outlet valve 71, effectively solves the problem of insufficient cooling water pressure in the air separation precooling system while meeting the operating pressure requirements of the chiller unit 3.

[0027] Furthermore, in this embodiment, a first pressure sensor 63 is provided on the first pipe 6 between the chiller unit 3 and the first outlet valve 61, and a second pressure sensor 73 is provided on the second pipe 7 between the chiller unit 3 and the chilled water pump 4.

[0028] In this embodiment, the outlet pressure of the pipeline pump 5 is monitored by the first pressure sensor 63 to ensure that the cooling water pressure after pressurization by the pipeline pump 5 does not exceed the operating pressure of the chiller unit 3. This embodiment also uses the second pressure sensor 73 to monitor the inlet pressure of the chilled water pump 4 to ensure that the cooling water pressure after the resistance of the chiller unit 3 is affected can meet the pressure requirements of the chilled water pump 4.

[0029] Furthermore, this embodiment also monitors the flow rate of cooling water entering the air-cooled tower 2 using a flow sensor 74 to ensure that the cooling water flow rate meets the heat exchange requirements of the air-cooled tower 2. Specifically, a flow sensor 74 is installed on the second pipe 7 between the air-cooled tower 2 and the second outlet valve 71. The flow rate of cooling water entering the air-cooled tower 2 can be adjusted by regulating the second outlet valve 71, while the flow sensor 74 can provide a direct and accurate view of the flow rate of cooling water entering the air-cooled tower 2.

[0030] In this embodiment, upon receiving notification that the water-cooled tower is supplying water to the top of the air-cooled tower 2, the first inlet valve 62 and the first outlet valve 61 are opened, and the control pipeline pump 5 is started to initially pressurize the chilled water in the first pipeline 6. The pressure of the cooling water entering the reciprocating chiller unit 3 is monitored by the first pressure sensor 63 to ensure that the pressure value is within 0.2 MPa. Then, the chilled water pump 4 is started, and the second outlet valve 71 is opened to begin supplying chilled water to the air-cooled tower 2. The chilled water flow rate is controlled by adjusting the opening degree of the second outlet valve 71 to achieve the set value required by the process.

[0031] Example 2:

[0032] Based on the same inventive concept as Embodiment 1, refer to Figure 1 In this embodiment, a first inlet valve 62 is provided on the first pipeline 6 located between the water cooling tower and the pipeline pump 5. A bypass pipe 8 is provided between the water cooling tower and the chiller unit 3, and a bypass valve 81 is provided on the bypass pipe 8. To avoid the impact of pipeline pump 5 maintenance on production, this embodiment also provides a bypass pipe 8 connecting the water cooling tower 1 and the chiller unit 3. When pipeline pump 5 needs maintenance, the first inlet valve 62 and the first outlet valve 61 can be closed, and the bypass valve 81 can be opened to allow cooling water to flow into the chiller unit 3 through the bypass pipe 8, thereby achieving maintenance without shutting down the system.

[0033] In this example, the second pipe 7 is located between the chilled water pump 4 and the chiller unit and is equipped with a second inlet valve 72.

[0034] In this embodiment, the pipeline pump 5, chilled water pump 4, first inlet valve 62, first outlet valve 61 and second outlet valve 71 are automatically controlled by a PLC controller, thereby improving system efficiency. The PLC controller in this embodiment is an S7-200 PLC.

[0035] In this embodiment, upon receiving a notification that the water-cooled tower is supplying water to the top of the air-cooled tower 2, the PLC controller receives the instruction and sends a signal to open the first inlet valve 62 and the first outlet valve 61, and starts the pipeline pump 5. Subsequently, it controls the second air inlet valve to open, venting the chilled water pump 4 and removing air from the chilled water pump 4 and the second pipeline 7. After venting is complete, the PLC controller sends a signal to start the chilled water pump 4 and opens the second outlet valve 71, beginning the supply of chilled water to the air-cooled tower 2. By adjusting the opening of the second outlet valve 71, the chilled water flow rate is controlled to achieve the set value required by the process.

[0036] The above description is only a preferred embodiment of this application. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of this disclosure / application, and these improvements and modifications should also be considered within the protection scope of this disclosure / application.

Claims

1. An air separation precooling system, comprising an air-cooled tower (2) and a water-cooled tower (1), wherein the water-cooled tower (1) is provided with a water outlet and the air-cooled tower (2) is provided with a water inlet, characterized in that, The outlet is connected to a chiller unit (3) via a first pipe (6). The chiller unit (3) is connected to the inlet via a second pipe (7). A pipeline pump (5) is installed on the first pipe (6), and a chilled water pump (4) is installed on the second pipe (7). A first outlet valve (61) is installed on the first pipe (6) between the chiller unit (3) and the pipeline pump (5). A second outlet valve (71) is installed on the second pipe (7) between the chilled water pump (4) and the air-cooled tower (2).

2. The air separation precooling system according to claim 1, characterized in that, The first pipe (6) is provided with a first pressure sensor (63) between the chiller unit (3) and the first outlet valve (61), and the second pipe (7) is provided with a second pressure sensor (73) between the chiller unit (3) and the chilled water pump (4).

3. The air separation precooling system according to claim 2, characterized in that, The second pipe (7) is located between the air-cooled tower (2) and the second outlet valve (71) and is equipped with a flow sensor (74).

4. The air separation precooling system according to claim 1, characterized in that, The second pipe (7) is located between the chilled water pump (4) and the chiller unit (3) and is equipped with a second inlet valve (72).

5. The air separation precooling system according to claim 1, characterized in that, The first pipeline (6) is located between the water cooling tower (1) and the pipeline pump (5) and is equipped with a first inlet valve (62); it also includes a PLC controller, which is connected to the pipeline pump (5), the chilled water pump (4), the first inlet valve (62), the first outlet valve (61) and the second outlet valve (71) respectively.

6. The air separation precooling system according to claim 5, characterized in that, A bypass pipe (8) is provided between the water cooling tower and the chiller unit (3), and a bypass valve (81) is provided on the bypass pipe (8).

7. The air separation precooling system according to claim 1, characterized in that, The chiller unit is a piston-type chiller unit (3).

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