Pre-cooling circulating cooling water system for air separation system

Abstract

The utility model provides a precooling circulating cooling water system for an air separation system. The precooling circulating cooling water system comprises an air cooling tower and a water cooling tower, a backflow chamber is arranged in the air cooling tower, a backflow pipe extending to the top in the water cooling tower is communicated in the backflow chamber, a water outlet pipe is communicated with the bottom in the water cooling tower, and a cooling pipe extending to the top in the air cooling tower is communicated with the middle section of the water outlet pipe; a first circulating pump and a water chilling unit are arranged on the cooling pipe. According to the precooling circulating cooling water system for the air separation system, two cooling water pipes are arranged, one cooling water pipe is an external water supply pipe, after being pressurized by a water pump, external supplied water enters the middle of an air cooling tower through a branch pipe and makes countercurrent direct contact with hot and humid air fed into the lower portion of the air cooling tower through a compressor, and the air is primarily cooled; and dust in the air can be washed and then discharged from the bottom of the tower. And the cooling pipe enters the top of the air cooling tower after heat exchange of the water chilling unit, and the air is cooled by the cooling pipe and discharged to the molecular sieve system.

Description

Technical Field

[0001] The utility model relates to the technical field of precooling circulating cooling water systems for air separation systems, in particular to a precooling circulating cooling water system for air separation systems. Background Art

[0002] In the existing air separation system, the pre-cooling circulating cooling water system is a key component, which is used to reduce the temperature of the gas entering the air separation unit and improve the separation efficiency. However, there are some shortcomings in the existing technology, especially in the cooling effect of circulating water.

[0003] Patent No. CN102466390A discloses a "method for increasing nitrogen production in an air separation plant". This method increases nitrogen production by setting up two cooling water systems in an air cooling tower. One of them is low-temperature cooling water after heat exchange with mixed nitrogen in the water cooling tower, and the other is normal temperature cooling water directly pumped into the middle of the air cooling tower by a water pump. This method aims to simplify the system and improve efficiency by eliminating the traditional chiller and using a water cooling tower instead.

[0004] Although the method proposed in CN102466390A is innovative, it does not completely solve the problem of high cooling water temperature. The two cooling waters are directly used for heat exchange in the water cooling tower, without considering the temperature matching of the cooling water and the circulating reflux hot water. The circulating reflux hot water temperature is too high, so that the temperature of the discharged cooling water is too high after the heat exchange in the water cooling tower, resulting in the water temperature of the cooling water failing to achieve the optimal heat exchange effect. Utility Model Content

[0005] The utility model provides a precooling circulating cooling water system for an air separation system, which is improved to achieve more effective heat exchange and more accurate temperature control.

[0006] The technical solution of the utility model is achieved in this way:

[0007] A precooling circulating cooling water system for an air separation system comprises an air cooling tower and a water cooling tower; a reflux chamber is provided in the air cooling tower, a reflux pipe extending to the top of the water cooling tower is connected to the reflux chamber, a water outlet pipe is connected to the bottom of the water cooling tower, and a cooling pipe extending to the top of the air cooling tower is connected to the middle section of the water outlet pipe; a first circulating pump and a chiller are provided on the cooling pipe;

[0008] It also includes an external water supply pipe, which is connected to a branch pipe extending to the lower position inside the air cooling tower near the end. The end of the external water supply pipe is connected to the return pipe, and the end of the outlet pipe is connected to the middle section of the external water supply pipe.

[0009] Furthermore, the external water supply pipe is provided with a second circulation pump located between the branch pipe and the water outlet pipe.

[0010] Furthermore, the external water supply pipe is provided with a control valve A located between the branch pipe and the return pipe.

[0011] Furthermore, the water outlet pipe is provided with a control valve B located between the external water supply pipe and the cooling pipe.

[0012] Furthermore, at least one water pipe distributor is provided at the ends of the cooling pipe, the reflux pipe and the branch pipe.

[0013] Beneficial effects of the technical solution provided by this application:

[0014] 1. The pre-cooling circulating cooling water system for the air separation system is provided with two cooling water pipes, one of which is an external water supply pipe. After being pressurized by a water pump, the external water enters the middle of the air cooling tower through a branch pipe, and directly contacts the hot and humid air sent to the lower part of the air cooling tower by the compressor in countercurrent, so that the air is initially cooled; it can also wash the dust in the air and then discharge it from the bottom of the tower. The other water pipe is supplied by the water cooling tower through the cooling pipe, and the cooling pipe enters the top of the air cooling tower after heat exchange with the chiller, and the air is cooled and discharged to the molecular sieve system through the cooling pipe.

[0015] 2. The pre-cooling circulating cooling water system used for the air separation system has the end of the external water supply pipe connected to the return loop pipe, so that the normal temperature cooling water is mixed with the circulating hot water in the middle of the air cooling tower, and the circulating hot water is cooled and enters the water cooling tower, which can not only replenish the water carried away by the nitrogen and ensure that the circulating water volume in the upper section of the air cooling tower is not reduced, but also ensure that the water temperature of the circulating hot water is reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0017] Figure 1 It is a schematic diagram of the pre-cooling circulating cooling water system of the utility model for an air separation system.

[0018] In the figure: 100 air cooling tower; 200 water cooling tower, 310 reflux pipe, 320 water outlet pipe, 321 control valve B, 330 cooling pipe, 331 first circulation pump, 332 chiller, 340 external water supply pipe, 341 branch pipe, 342 second circulation pump, 343 control valve A. DETAILED DESCRIPTION

[0019] The technical solution of the utility model will be described clearly and completely in conjunction with the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of them. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0020] Reference Figure 1 A precooling circulating cooling water system for an air separation system comprises an air cooling tower 100 and a water cooling tower 200; a reflux chamber 120 is provided in the air cooling tower 100, a reflux pipe 310 extending to the top of the water cooling tower 200 is connected to the reflux chamber 120, a water outlet pipe 320 is connected to the bottom of the water cooling tower 200, and a cooling pipe 330 extending to the top of the air cooling tower 100 is connected to the middle section of the water outlet pipe 320; a first circulating pump 331 and a chiller 332 are provided on the cooling pipe 330;

[0021] It also includes an external water supply pipe 340, which is connected to a branch pipe 341 extending to the lower position inside the air-cooling tower 100 near the end. The end of the external water supply pipe 340 is connected to the return pipe 310, and the end of the water outlet pipe 320 is connected to the middle section of the external water supply pipe 340.

[0022] The air cooling tower 100 is a place where air and cooling water perform heat exchange, and is used to reduce the air temperature. The water cooling tower 200 is a place where cooling water performs heat exchange, and is used to reduce the temperature of cooling water. The reflux chamber 120 is located in the air cooling tower 100, and is the starting point of the circulating water reflux, and is connected to the top of the water cooling tower 200 through the reflux pipe 310. The reflux pipe 310 connects the reflux chamber 120 of the air cooling tower 100 and the top of the water cooling tower 200, and is used to send the hot water in the air cooling tower back to the water cooling tower for recooling. The water outlet pipe 320 is located at the bottom of the water cooling tower 200, and is used to return the cooled water to the air cooling tower 100. The cooling pipe 330 connects the water cooling tower 200 and the air cooling tower 100, and is equipped with a first circulating pump 331 and a chiller 332 inside, which is used to send the external water supply to the air cooling tower for air cooling after being cooled by the chiller. The first circulation pump 331 is installed on the cooling pipe 330 to provide power for the water flow and ensure that the cooling water circulates in the system. The chiller 332 is installed on the cooling pipe 330 together with the first circulation pump 331 to reduce the temperature of the cooling water and improve the cooling efficiency. The external water supply pipe 340 introduces water into the system from an external water source, and the end is connected to the return pipe 310, and the middle section is connected to the outlet pipe 320. The branch pipe 341 extends from the external water supply pipe 340 to the lower position inside the air cooling tower 100, and is used to divide the external water supply into two routes, one part of which enters the middle part of the air cooling tower for heat exchange.

[0023] Furthermore, the external water supply pipe 340 is provided with a second circulation pump 342 located between the branch pipe 341 and the water outlet pipe 320. The second circulation pump 342 is installed on the external water supply pipe 340, located between the branch pipe 341 and the water outlet pipe 320, for providing additional water flow power.

[0024] The second circulating pump 342 is provided to provide additional power in the external water supply pipe 340 to ensure that the water flow has sufficient flow rate and pressure before entering the air cooling tower 100 through the branch pipe 341 and in the circulation process after the middle section of the outlet pipe 320 is connected with the middle section of the external water supply pipe 340. Such a configuration helps to maintain the dynamic balance of the water flow inside the entire pre-cooling circulating cooling water system. At the same time, through the adjustment of the second circulating pump 342, the cooling water flow entering the air cooling tower 100 can be more accurately controlled to meet the needs of the system under different working conditions. In addition, the addition of the second circulating pump 342 can also reduce the water flow slowdown caused by pressure loss in the system to a certain extent, ensure that the cooling water can effectively circulate between the air cooling tower and the water cooling tower, achieve efficient heat exchange, and thus improve the cooling efficiency and stability of the entire air separation system.

[0025] Furthermore, the external water supply pipe 340 is provided with a control valve A343 located between the branch pipe 341 and the return pipe 310. The control valve A343 is installed on the external water supply pipe 340, located between the branch pipe 341 and the return pipe 310, and is used to control the amount of water flowing to the return pipe.

[0026] The setting of the control valve A343 allows the operator to accurately adjust the water flow entering the return pipe 310 according to the actual operation of the system. Since the return pipe 310 is responsible for redirecting the cooled water in the water cooling tower 200 back to the top of the air cooling tower 100, the control valve A343 plays a vital role in this process. By adjusting the opening of the control valve A, the flow rate and pressure of the water flow in the external water supply pipe 340 can be controlled, thereby affecting the amount of water entering the air cooling tower 100 through the branch pipe 341 and the amount of water returning to the water cooling tower 200.

[0027] This regulation mechanism enables the system to dynamically adjust the distribution of cooling water according to cooling demand and heat exchange efficiency, and optimize the entire cooling cycle. For example, when the system load is high, the opening of control valve A can be increased to increase the amount of cooling water entering the air cooling tower to improve cooling efficiency; when the system load is low, the opening can be reduced to reduce the amount of cooling water to save energy consumption. In addition, the regulation of control valve A343 also helps to maintain a constant temperature of cooling water in the system, ensuring that the heat exchange efficiency of air and water is maximized, thereby improving the precooling effect and overall performance of the entire air separation system.

[0028] Furthermore, the water outlet pipe 320 is provided with a control valve B321 located between the external water supply pipe 340 and the cooling pipe 330. The control valve B321 is installed on the water outlet pipe 320, located between the external water supply pipe 340 and the cooling pipe 330, and is used to control the water flow in the water outlet pipe.

[0029] The setting of the control valve B321 allows the system operator to dynamically adjust the water flow in the water outlet pipe 320 according to the real-time monitored cooling water temperature and system load. Since the water outlet pipe 320 is responsible for transporting the preliminarily cooled water in the water cooling tower 200 back to the cooling pipe 330 of the air cooling tower 100 for further cooling, the control valve B plays a key role in this process.

[0030] By adjusting the opening of the control valve B321, the flow rate and speed of the water flow in the water outlet pipe can be controlled, thereby affecting the supply of cooling water in the cooling pipe 330. When the system load is high and greater cooling capacity is required, increasing the opening of the control valve B can increase the flow rate of cooling water and improve cooling efficiency; on the contrary, when the system load is low, reducing the opening of the control valve B can reduce the flow rate of cooling water and reduce energy consumption.

[0031] In addition, the adjustment of control valve B321 also helps to optimize the circulation of cooling water between the air cooling tower and the water cooling tower, ensuring that the cooling water can effectively absorb the heat of the air after the heat exchange of the chiller 332, thus achieving efficient heat exchange. This precise flow control mechanism not only improves the cooling efficiency of the system, but also enhances the flexibility and adaptability of the system, ensuring that the entire air separation system can maintain the best operating state under different working conditions.

[0032] Furthermore, at least one water pipe distributor is disposed at the end of the cooling pipe 330, the return pipe 310 and the branch pipe 341. The water pipe distributor is disposed at the end of the cooling pipe 330, the return pipe 310 and the branch pipe 341 to distribute the water flow direction and flow rate.

[0033] The function of the water pipe distributor is to provide accurate distribution of water flow at the ends of the cooling pipe 330, the return pipe 310 and the shunt pipe 341. At the end of the cooling pipe 330, the distributor evenly distributes the water cooled by the chiller 332 to the top of the air cooling tower 100 to achieve effective heat exchange between air and cooling water. At the end of the return pipe 310, the distributor ensures that the cooling water collected from the bottom of the water cooling tower 200 can be properly distributed and sent back to the top of the air cooling tower to maintain the circulation of water. At the end of the shunt pipe 341, the distributor is responsible for distributing the water flow introduced by the external water supply pipe 340 to the middle part of the air cooling tower 100, and performing heat exchange with the hot and humid air rising in the tower.

[0034] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A precooling circulating cooling water system for an air separation system, comprising an air cooling tower (100) and a water cooling tower (200); a reflux chamber (120) is provided in the air cooling tower (100), a reflux pipe (310) extending to the top of the water cooling tower (200) is connected in the reflux chamber (120), a water outlet pipe (320) is connected to the bottom of the water cooling tower (200), a middle section of the water outlet pipe (320) is connected to a cooling pipe (330) extending to the top of the air cooling tower (100); a first circulating pump (331) and a chiller (332) are provided on the cooling pipe (330); It is characterized in that It also includes an external water supply pipe (340), the external water supply pipe (340) is connected to a branch pipe (341) extending to the lower position inside the air cooling tower (100) near the end, the end of the external water supply pipe (340) is connected to the return pipe (310), and the end of the water outlet pipe (320) is connected to the middle section of the external water supply pipe (340).

2. The precooling circulating cooling water system for an air separation system according to claim 1, characterized in that: The external water supply pipe (340) is provided with a second circulation pump (342) located between the branch pipe (341) and the water outlet pipe (320).

3. The precooling circulating cooling water system for an air separation system according to claim 1, characterized in that: The external water supply pipe (340) is provided with a control valve A (343) located between the branch pipe (341) and the return pipe (310).

4. The precooling circulating cooling water system for an air separation system according to claim 1, characterized in that: The water outlet pipe (320) is provided with a control valve B (321) located between the external water supply pipe (340) and the cooling pipe (330).

5. The precooling circulating cooling water system for an air separation system according to claim 1, characterized in that: At least one water pipe distributor is provided at the ends of the cooling pipe (330), the return pipe (310) and the branch pipe (341).

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