Air separation oxygen production nitrogen water pre-cooling system water circulation independent large circulating water system and process method

Abstract

The invention discloses a water circulation independent large circulating water system of an air separation oxygen production nitrogen water precooling system and a process method, the system comprises a nitrogen water precooling water circulation system and a dynamic equipment water circulation system, different cooling tower structures are designed for two paths of water, and cleaning and maintenance of equipment are facilitated. According to the invention, a physically-isolated double-circulation water system is constructed, so that an easily-polluted nitrogen water pre-cooling process is separated from cooling of clean equipment. The closed circulating system avoids pollutant invasion, and the open system is compatible with high pollution load and strengthens pollution discharge. The problems of deposition blockage and corrosion of the cooler are thoroughly solved. The manhole can be opened once every three years for inspection, the inspection effect is good, the amount of rusted substances scraped from the inner wall and the amount of sludge cleaned from the bottom are small, the situation that abnormity occurs during operation is not worried any more, and the service life of the tower body is prolonged.

Description

Technical Field

[0001] This invention belongs to the field of air separation technology, specifically relating to an independent large circulating water system and process method for an air separation oxygen and nitrogen water precooling system. Background Technology

[0002] The statements herein provide only background information in relation to this invention and do not necessarily constitute prior art.

[0003] Air separation technology utilizes the different physical properties of air components to separate oxygen and nitrogen from the air. The air separation process generally involves: first, air from the external environment is filtered through an air filter to remove larger particles; second, it is compressed by an air compressor to obtain higher pressure air; then, the compressed air is pre-cooled in a cooling device to obtain lower temperature air; next, the air is passed into a purification system to remove moisture and other gaseous impurities; finally, the high-pressure, pure air is sent to a fractionation tower for separation to obtain liquid oxygen and liquid nitrogen.

[0004] Current cryogenic air separation equipment and its associated circulating water system are in the form of a single-loop water structure, similar to the structure disclosed in patent CN121206835A. This system employs a circulating water tank and a cooling tower. The main function of the circulating water is to cool the oil and gas in key moving parts (including air compressor units, refrigerant condensers, and expanders) and to cool and wash the air in the nitrogen-water precooling system. The circulating water flows through the nitrogen-water precooling system and the moving parts cooling system. During the heat exchange, cooling, and washing of hot air in the air-cooling tower of the nitrogen-water precooling system, mechanical particulate impurities such as dust and chemical substances (such as SO2 and Cl2) in the compressed air also enter the circulating water and finally return to the circulating water tank in the return water pipe. Because the equipment water and the air cooling and washing water share a common water tank and circulating water pipes, after repeated use, dust and suspended matter accumulate in the circulating water and at the bottom of the tank. After continuous circulation, these suspended dust particles eventually deposit in the cooler of the moving equipment. Clean water is required here; water containing suspended particles severely affects the cooler's cooling efficiency and easily causes pitting and under-deposit corrosion on pipes and coolers, not only impacting heat exchange but also posing safety hazards. Although the air compressor inlet has a self-cleaning filter and the circulating water has a chemical dosing system, because the air separation unit operates continuously year-round, a large amount of sediment accumulates on the cooler, the bottom of the air-cooled tower, and the bottom of the water-cooled tower during shutdown maintenance. It is evident that contaminants introduced by the nitrogen-water precooling system will reduce the cooler's heat exchange efficiency, and the resulting corrosion will significantly shorten equipment lifespan. Frequent shutdowns for cleaning also substantially increase annual maintenance costs. Summary of the Invention

[0005] To address these issues, this invention proposes separating the nitrogen-water precooling system in the air separation unit from the original large air separation circulation system. This creates two separate cooling water streams for the air separation process. One stream is a closed-loop circulation system (equipped with a separate water tank and closed cooling tower) specifically for cooling moving equipment, while the other stream uses a separate circulation system (equipped with a separate water tank and open cooling tower) specifically for the nitrogen-water precooling system, achieving isolation between the pollution source and the clean cooling system. Furthermore, this invention designs different cooling tower structures for the two water streams, facilitating equipment cleaning and maintenance.

[0006] The above objectives are achieved by the present invention through the following technical solution:

[0007] In a first aspect, the present invention provides an independent large circulating water system for the air separation oxygen production nitrogen water precooling system, which includes two parts: a nitrogen water precooling water circulation system and a moving equipment water circulation system. The nitrogen-water precooling water circulation system includes a nitrogen-water precooling circulation pool, which is connected in parallel to an air-cooled tower and a water-cooled tower via a first circulation water pipeline. The first circulation water pipeline is connected to the middle layer of the air-cooled tower to perform preliminary cooling of the air from the air compressor. The exhaust water from the bottom of the water-cooled tower is connected to the upper layer of the air-cooled tower to further cool the air from the air compressor.

[0008] In an embodiment of the present invention, a nitrogen water precooling circulating water pump is installed on the first circulating water pipeline, a nitrogen water precooling cooling water pump is installed on the water pipe connected to the air-cooled tower, and then connected to the middle layer of the air-cooled tower; a nitrogen water precooling chilled water pump and a chiller are sequentially installed on the water pipe connecting the bottom of the water-cooled tower and the upper layer of the air-cooled tower.

[0009] Water discharged from the bottom of the air-cooled tower is transported through water pipes to the open cooling tower and the nitrogen-water precooling circulating water pool. The open cooling tower is located on top of the nitrogen-water precooling circulating water pool. A fan and an air inlet louver are installed at the air inlet of the open cooling tower. The former accelerates airflow and improves heat exchange, while the latter prevents debris from falling into the circulating water pool and makes the air intake more uniform.

[0010] Because a large amount of dust remains in the circulating water of the nitrogen precooling process, chemical treatment is applied to this route of the nitrogen precooling water circulation system. Simultaneously, the bottoms of the water cooling tower and air cooling tower are cleaned during the maintenance period.

[0011] The nitrogen-water precooling water circulation system also includes a dosing machine connected to the nitrogen-water precooling circulation water tank. In existing devices, the dosing point is generally before the cooling water enters the heat exchanger to ensure uniform mixing of the chemicals. Considering the structural characteristics of the nitrogen-water precooling water circulation system provided by this invention, the following method is adopted: water is drawn from the outlet of the nitrogen-water precooling circulation pump and connected to the inlet of the dosing machine. After the dosing machine system performs detection and dosing processes, the water returns to the nitrogen-water precooling circulation water tank via the return pipe. This ensures that the water supplied to the dosing device has sufficient pressure to ensure circulation.

[0012] In the nitrogen-water precooling system, sludge mainly accumulates at the bottom of the air-cooled tower. To prevent sludge deposition and ensure water quality meets relevant standards, a portion of the water is periodically discharged weekly through the drain outlet at the bottom of the air-cooled tower during normal operation to replace the sludge, thus replenishing the water and also serving as a sludge discharge. Additionally, during the 1-2 year maintenance period, the manholes at the bottom of the air-cooled tower and water-cooled tower are opened for inspection and cleaning. Compared to traditional methods, the water circulation system structure provided in this application results in less sediment at the bottom of the air-cooled tower and reduced corrosion of the tower body.

[0013] The aforementioned dynamic equipment water circulation system includes a closed-loop circulating water tank, which is a closed container. The closed-loop circulating water tank is connected in parallel to the air compressor unit, refrigerant condenser and expander unit through a second circulating water pipeline, and then connected to a closed-loop water-cooling tower installed above the closed-loop circulating water tank. A closed-loop circulating water pump is installed at the outlet of the closed-loop circulating water tank in the second circulating water pipeline.

[0014] The difference between a closed-loop water-cooled tower structure and an open-loop cooling tower structure with a nitrogen-water precooling water circulation system is that a closed-loop water-cooled tower is completely enclosed. At the same time, a water coil is installed inside the closed-loop water-cooled tower to connect the circulating water of the automatic equipment (including air compressor units, refrigerant condensers and expanders) to the water coil, and then transport it to the closed-loop circulating water pool.

[0015] The closed-loop water-cooled tower is not directly connected to the closed-loop circulating water tank; its bottom is connected to the closed-loop tower water storage tank. The closed-loop tower water storage tank is connected to the top of the closed-loop water-cooled tower via a spray circulation pipe. Spray nozzles are installed at the outlet to spray and cool the water coils within the closed-loop water-cooled tower. A spray circulation pump is installed on the spray circulation pipe. A fan is installed at the top of the closed-loop water-cooled tower to accelerate the cooling rate of the water in the water coils.

[0016] Water is replenished periodically according to the liquid level in the closed tower water storage tank. In order to ensure the cleanliness of the spray water, a branch line is led out downstream of the spray circulation pump on the spray circulation pipe and connected to the dosing machine to apply the agent. The dosing machine pipeline is directly connected to the closed tower water storage tank.

[0017] Similarly, in order to ensure the cleanliness of the water in the closed-loop circulating water tank, water is drawn from the outlet of the closed-loop circulating water pump, connected to the inlet of the dosing machine, and then returned to the closed-loop circulating water tank through the return pipe after the dosing machine system detects and adds chemicals.

[0018] In the closed-loop circulation system of the moving equipment, the contact between circulating water and air is eliminated; a closed cooling tower is used to prevent pollution; the water quality meets the national standard for closed-loop circulating cooling water: total iron ≤ 2.0 mg / l.

[0019] In a second aspect, the present invention provides a process method for the independent large circulating water system of the air separation oxygen and nitrogen water precooling system, based on the air separation oxygen and nitrogen water precooling system water circulation system provided in the first aspect, including the water circulation process of the moving equipment and the water circulation process of the nitrogen water precooling system.

[0020] The water circulation process of the moving equipment involves the circulating water in the closed-loop circulating water tank being pumped and pressurized into the circulating pipe network of the moving equipment under the drive of the closed-loop circulating water pump. After heat exchange with each equipment cooler and oil cooler, the water enters the return water circulating pipe network and is then sent to the heat dissipation pipe of the closed water cooling tower. After cooling, the water collects and falls into the closed-loop circulating water tank. This circulation path can be ideally considered as a closed space.

[0021] The nitrogen-water precooling system's water circulation process involves the following steps: After being pumped and pressurized by the nitrogen-water precooling circulating water pump, a portion of the circulating water in the nitrogen-water precooling circulating water tank is further pressurized by the nitrogen-water precooling cooling water pump and sent to the middle of the air-cooled tower for counter-current heat exchange and cooling with the air; the other portion of the circulating water is supplied to the top of the water-cooled tower for counter-current heat exchange and cooling with the waste nitrogen gas. Water falling back to the bottom of the water-cooled tower is then pressurized by the nitrogen-water precooling chilled water pump and sent to the top of the air-cooled tower for counter-current heat exchange and cooling with the air. If the temperature of this portion of water does not meet the process requirements, it is further cooled by the refrigeration unit before being sent to the top of the air-cooled tower. Water in the top and middle sections of the air-cooled tower, after exchanging heat with the air, falls back to the bottom and, under the pressure within the tower, returns to the water tank and the open-type heat dissipation tower, thus completing the cycle.

[0022] The beneficial effects achieved by one or more embodiments of the present invention described above are as follows: 1. This invention provides an independent main circulating water system for the oxygen and nitrogen pre-cooling system in air separation. The invention designs two circulating water paths: one dedicated to supplying cooling water for moving equipment, and the other dedicated to supplying water for the nitrogen pre-cooling system. Each of these paths is equipped with its own water tank and heat dissipation tower. Furthermore, the heat dissipation tower used by the moving equipment is a closed-loop tower, forming a sealed system with the moving equipment cooler and circulating pipelines, effectively preventing dust and other contaminants from entering the water system. The system and process provided by this invention fundamentally isolate the source of pollution from the clean cooling system.

[0023] 2. Based on the system and process provided by this invention, deposits in the cooler of moving equipment are reduced; the rate of corrosion is reduced; the components of equipment cleaning and maintenance are reduced; and production efficiency is improved. Attached Figure Description

[0024] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0025] Figure 1 This is a schematic diagram of the nitrogen water precooling water circulation system in the air separation oxygen production nitrogen water precooling system provided by the present invention, which is an independent main circulating water system.

[0026] Figure 2 This is a schematic diagram of the water circulation system of the air separation oxygen and nitrogen water precooling system provided by the present invention, which is an independent water circulation system of the main circulating water system.

[0027] Figure 3 This is a schematic diagram of the water circulation system structure of a traditional air separation device.

[0028] Among them, 101-nitrogen water precooling circulating water tank, 102-air cooling tower, 103-water cooling tower, 104-open cooling tower, 105-fan, 106-air inlet louver fan, 107-dosing machine, 108-nitrogen water precooling circulating water pump. 1021-Cooling water pump, 1022-Chiller water pump, 1023-Refrigeration unit; 201-Closed-loop circulating water tank, 202-Air compressor unit, 203-Refrigerant condenser, 204-Expander unit, 205-Closed-loop water cooling tower, 206-Closed-loop tower water storage tank, 207-Water coil, 208-Spray circulation pipe, 209-Closed-loop circulating water pump; P1 - First circulating water pipeline, P2 - Second circulating water pipeline. Detailed Implementation

[0029] It should be noted that the following detailed description is illustrative and intended to provide further explanation of the invention. Unless otherwise specified, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0030] The present invention will be further described below with reference to the embodiments.

[0031] Example 1: The water circulation system of the air separation oxygen and nitrogen water precooling system is independent of the main circulating water system. It consists of two parts: a nitrogen-water precooling water circulation system and a dynamic equipment water circulation system.

[0032] The nitrogen-water precooling water circulation system, such as Figure 1 As shown, it includes a nitrogen-water precooling circulating water tank 101, which is connected in parallel to an air-cooled tower 102 and a water-cooled tower 103 via a first circulating water pipeline P1. A nitrogen-water precooling circulating water pump 108 is installed on the first circulating water pipeline P1. A standby cooling water pump 1021 is installed on the water pipe connected to the air-cooled tower 102 and then connected to the middle layer of the air-cooled tower 102 to perform preliminary cooling of the air from the air compressor. The drain water at the bottom of the water-cooled tower 103 is connected to the upper layer of the air-cooled tower 102 to further cool the air from the air compressor. A standby chilled water pump 1022 and a chiller 1023 are sequentially installed on the water pipe connecting the bottom of the water-cooled tower 103 and the upper layer of the air-cooled tower 102.

[0033] Water discharged from the bottom of the air-cooled tower 102 is transported to the open cooling tower 104 through a water pipe. The open cooling tower 104 is located on top of the nitrogen-water precooling circulating water pool 101. A fan 105 and an air inlet louver fan 106 are installed at the air inlet of the open cooling tower 104. The former accelerates airflow and improves heat exchange effect, while the latter prevents debris from falling into the circulating water pool and makes the air intake more uniform.

[0034] Because a large amount of dust remains in the circulating water of the nitrogen precooling process, chemical treatment is applied to this route of the nitrogen precooling water circulation system. Simultaneously, the bottoms of the water cooling tower and air cooling tower are cleaned during the maintenance period.

[0035] The nitrogen-water precooling water circulation system is also equipped with a dosing machine 107 connected to the nitrogen-water precooling circulation water tank 101. In existing devices, the dosing point is generally before the cooling water enters the heat exchanger to ensure uniform mixing of the chemicals. Considering the structural characteristics of the nitrogen-water precooling water circulation system provided by this invention, in order to ensure that the water supplied to the dosing device 107 has sufficient pressure to ensure circulation, water is drawn from the outlet of the nitrogen-water precooling circulation water pump 108 and connected to the inlet of the dosing machine 107. After the dosing machine system detects and performs dosing, the water returns to the nitrogen-water precooling circulation water tank 101 through the return water pipe.

[0036] The chemicals applied by the dosing machine 107 are mainly slow-release agents (to prevent corrosion of carbon steel, stainless steel, and copper, mainly containing phosphorus, zinc, and BAT / TTA) and scale inhibitors (organophosphorus and carboxylates). The concentration of chemicals and the conductivity of circulating water are controlled by online dosing equipment.

[0037] Sludge mainly accumulates at the bottom of the air-cooled tower. To prevent sludge deposition and ensure water quality meets relevant standards, during normal operation, a portion of the water is periodically discharged once a week through the drain outlet at the bottom of the air-cooled tower for replacement, which both replenishes the water and serves as a sludge removal function. Additionally, during the 1-2 year maintenance period, the manholes at the bottom of the air-cooled tower and water-cooled tower are opened for inspection and cleaning. National standards for open-loop circulating cooling water quality are: turbidity ≤ 10 NTU, total Fe ≤ 2.0 mg / L, copper ions ≤ 0.1 mg / L, and CL... - ≤1000mg / l. Compared with the traditional method, there is less sediment at the bottom and less corrosion of the tower body.

[0038] The aforementioned moving equipment water circulation system, such as Figure 2 As shown, it includes a closed-loop circulating water tank 201, which is a closed container. The closed-loop circulating water tank 201 is connected in parallel to the air compressor unit 202, the refrigerant condenser 203 and the expander unit 204 through the second circulating water pipeline P2, and then connected to the closed-loop water cooling tower 205 set above the closed-loop circulating water tank 201. The second circulating water pipeline P2 is equipped with a closed-loop circulating water pump 209 at the outlet of the closed-loop circulating water tank 201.

[0039] The difference between the closed-loop water cooling tower 205 and the open-loop cooling tower 104 of the nitrogen precooling water circulation system is that the closed-loop water cooling tower 205 is completely enclosed. At the same time, a water coil is installed inside the closed-loop water cooling tower 205 to connect the circulating water of the automatic equipment (including air compressor unit 202, refrigerant condenser 203 and expander unit 204) to the water coil 207, and then transport it to the closed-loop circulating water pool 201.

[0040] The closed-loop water-cooled tower 205 is not directly connected to the closed-loop circulating water tank 201; its bottom is connected to the closed-loop tower water storage tank 206. The closed-loop tower water storage tank 206 is connected to the top of the closed-loop water-cooled tower 205 via a spray circulation pipe 208. A spray nozzle is installed at the outlet to spray and cool the water coil 207 in the closed-loop water-cooled tower 205. A spray circulation pump is installed on the spray circulation pipe 208. A fan is installed at the top of the closed-loop water-cooled tower 205 to accelerate the cooling rate of the water in the water coil.

[0041] Water is replenished periodically according to the liquid level in the closed tower water storage tank 206. In order to ensure the cleanliness of the spray water, a branch line is led out from the downstream of the spray circulation pump on the spray circulation pipe 208 to the dosing machine to apply the agent. The dosing machine pipeline is directly connected to the closed tower water storage tank 206.

[0042] Similarly, in order to ensure the cleanliness of the water in the closed-loop circulating water tank 201, water is drawn from the outlet of the closed-loop circulating water pump 209 and connected to the inlet of the dosing machine. After the dosing machine system detects and adds chemicals, the water is returned to the closed-loop circulating water tank 201 through the return pipe.

[0043] In the closed-loop circulation system of the moving equipment, the contact between circulating water and air is eliminated; a closed cooling tower is used to prevent pollution; the water quality meets the national standard for closed-loop circulating cooling water: total iron ≤ 2.0 mg / l.

[0044] Example 2 Pre-cooling process method for air separation oxygen production equipment Based on the air separation oxygen and nitrogen water precooling system provided in Example 1, a separate large circulating water system is provided, including the water circulation process of the moving equipment and the water circulation process of the nitrogen water precooling system.

[0045] The water circulation process of the moving equipment involves the circulating water in the closed-loop circulating water tank 201 being pumped and pressurized by the closed-loop circulating water pump 209 and entering the circulating pipe network of the moving equipment. After heat exchange with each equipment cooler and oil cooler, the water enters the return water circulating pipe network and is then sent to the heat dissipation pipe of the closed water cooling tower. After cooling, the water collects and falls into the closed-loop circulating water tank 201. This circulation path can be ideally considered as a closed space.

[0046] Given the characteristics of the closed tower, the cooling still relies on water evaporation. This part of the water accumulates in the water basin supporting the closed tower (or when customizing new equipment, a water basin is not used and a water pool is directly built on site), and is circulated and sprayed for evaporation cooling, and the water level in the water basin is replenished regularly by the water replenishing valve.

[0047] The closed - cycle water pool 201 (or traditional water pool) used for cooling the dynamic equipment cooler is generally arranged at the idle position in the factory area on one side of the air compressor room. For a newly built water circulation system, if the present invention is adopted, the two water pools, namely the closed - cycle water pool 201 and the nitrogen - water precooling cycle water pool 101, can be arranged in parallel, which is convenient for laying the water replenishing pipeline, power, signal cables and sewage pipelines; for an in - use air separation unit, if the present invention is adopted, it is recommended to place it near the nitrogen - water precooling room, which can save the civil engineering cost of building the water pool, the cost of water pipeline materials, and also save the construction time, and can be completed by means of transformation during the major overhaul interval of the air separation unit.

[0048] In the water circulation process of the nitrogen - water precooling system, after the circulating water in the nitrogen - water precooling cycle water pool 101 is pumped and pressurized by the nitrogen - water precooling circulating water pump 108, a part of it is further pressurized by the cooling water pump and sent to the middle of the air cooling tower for counter - current heat exchange and washing cooling with air; another part of the circulating water is supplied to the top of the water cooling tower for counter - current heat exchange cooling with the dirty nitrogen. The water that falls back to the bottom of the water cooling tower is then pressurized by the refrigeration water pump and sent to the top of the air cooling tower for counter - current heat exchange and washing cooling. If the temperature of this part of the water does not meet the process requirements, it is further cooled by the refrigeration unit and then sent to the top of the air cooling tower. The water at the top and middle of the air cooling tower returns to the lower part after heat exchange with air, and under the action of the pressure in the tower, it returns to the water pool and the open - type cooling tower, and circulates in this way.

[0049] Comparative Example 1 It is the water circulation system structure of an air separation unit that adopts the same set of water pool and cooling device.

[0050] As Figure 3 shown, the water in the water pool 301 is respectively connected in series to the air compressor unit 202, the refrigerant condenser 203, the expansion unit 204, the air cooling tower 102 and the water cooling tower 103, and then returns to the open - type cooling tower 104. A chemical dosing machine 107 is arranged in the water pool.

[0051] The traditional method is to build a water pool for the air separation unit, and support an open - type (cross - flow or counter - flow) tower, circulating water pumps, inlet and return water pipelines, chemical dosing devices, etc. The inlet pipeline distributes water to water - using equipment, towers, etc., and the corresponding return water enters the return water pipeline and returns to the water pool and the open - type tower for cooling.

[0052] After the circulating water pump draws water from the pool and pressurizes it, it is distributed through the inlet pipe to the water used in the moving equipment and the nitrogen precooling system. The circulating water returns to the return water pipe after heat exchange in the moving equipment heat exchanger. In the nitrogen precooling system, it is collected at the bottom of the air-cooled tower and returns to the return water pipe. Both of these main parts of the return water return to the open tower in the pool for heat dissipation. In this way, the water used for washing the air accumulates a large amount of dust under continuous circulation, and although there is a matching sand filter, the effect is generally poor.

[0053] Test case The company's Phase I plant adopts the system structure provided in the comparative example, while the two Phase II plants adopt the system structure provided in Example 1 and the process method in Example 2. During two maintenance inspections of the air compressors over six years, it was found that the closed-loop tower circulating water circuit supplied to the dynamic equipment cooler provided in Example 1 had no dust adhering to the cooler pipe walls or inner pipe walls. Upon disassembling and inspecting the water-side seals of the cooler, the inner walls of the cooling pipes were clean, free of scale and mud, requiring no separate cleaning treatment.

[0054] In Comparative Example 1, the equipment was covered with a large amount of sludge, which seriously affected heat exchange. This was especially true for the oil cooler; some brands of air compressors have smaller oil coolers with thinner heat exchange tubes, making them prone to accumulating dust and sludge. After modifying the system in Comparative Example 1 to the structure of Example 1, the water-side portion of the heat exchanger in the moving equipment showed excellent results. This eliminated the previous requirement to clean the air compressor oil cooler and interstage cooler before summer, a process that, if delayed, would inevitably lead to oil temperature alarms, insufficient air volume, and even compressor surge and shutdown in the summer.

[0055] In the closed-loop circulation system of the moving equipment, the contact between circulating water and air is eliminated; a closed cooling tower is used to prevent pollution; the water quality meets the national standard for closed-loop circulating cooling water: total iron ≤ 2.0 mg / l.

[0056] The maintenance cycle has been adjusted from once a year for major overhaul to once every three years for manhole inspection. According to the inspection results, the effect is very good. Very little rust is scraped off from the inner wall and very little sludge is cleaned from the bottom, which has prevented any abnormalities from occurring during operation and has extended the service life of the tower.

[0057] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. The water circulation system of the air separation oxygen and nitrogen water precooling system is independent of the main circulating water system, characterized in that, It consists of two parts: a nitrogen-water precooling water circulation system and a dynamic equipment water circulation system; The nitrogen-water precooling water circulation system includes a nitrogen-water precooling circulation pool, which is connected in parallel to an air-cooled tower and a water-cooled tower via a first circulation water pipeline. The first circulation water pipeline is connected to the middle layer of the air-cooled tower to perform preliminary cooling of the air from the air compressor. The exhaust water from the bottom of the water-cooled tower is connected to the upper layer of the air-cooled tower to further cool the air from the air compressor.

2. The air separation oxygen and nitrogen water precooling system according to claim 1 has a water circulation system that is independent of the main circulating water system, characterized in that, Water discharged from the bottom of the air-cooled tower is transported to the open cooling tower through water pipes. The open cooling tower is located on top of the nitrogen-water precooling circulating water pool, and a fan and air inlet louvers are installed at the air inlet of the open cooling tower.

3. The air separation oxygen and nitrogen water precooling system according to claim 1 has a water circulation system that is independent of the main circulating water system, characterized in that, The nitrogen water precooling water circulation system is also equipped with a dosing machine connected to the nitrogen water precooling circulation water tank.

4. The air separation oxygen and nitrogen water precooling system according to claim 1 has a water circulation system that is independent of the main circulating water system, characterized in that, A nitrogen water precooling circulating water pump is installed on the first circulating water pipeline, and a nitrogen water precooling cooling water pump is installed on the water pipeline connected to the air-cooled tower, and then connected to the middle layer of the air-cooled tower; a nitrogen water precooling chilled water pump and a chiller are installed sequentially on the water pipeline connecting the bottom of the water-cooled tower and the upper layer of the air-cooled tower.

5. The air separation oxygen and nitrogen water precooling system according to claim 1 has a water circulation system that is independent of the main circulating water system, characterized in that, The aforementioned dynamic equipment water circulation system includes a closed-loop circulating water tank, which is a closed container. The closed-loop circulating water tank is connected in parallel to the air compressor unit, refrigerant condenser and expander unit through a second circulating water pipeline, and then connected to a closed-loop water-cooling tower installed above the closed-loop circulating water tank. A closed-loop circulating water pump is installed at the outlet of the closed-loop circulating water tank in the second circulating water pipeline.

6. The air separation oxygen and nitrogen water precooling system according to claim 5 has a water circulation system that is independent of the main circulating water system, characterized in that, The closed-loop water-cooled tower is completely enclosed. At the same time, a water coil is installed inside the closed-loop water-cooled tower so that the circulating water of the automatic equipment is connected to the water coil and then transported to the closed-loop circulating water tank.

7. The air separation oxygen and nitrogen water precooling system according to claim 6 has a water circulation system that is independent of the main circulating water system, characterized in that, The moving equipment includes an air compressor unit, a refrigerant condenser, and an expander unit.

8. The air separation oxygen and nitrogen water precooling system according to claim 6 has a water circulation system that is independent of the main circulating water system, characterized in that, The closed-loop water cooling tower is not directly connected to the closed-loop circulating water tank. The bottom of the closed-loop water cooling tower is connected to the closed-loop tower water storage tank. The closed-loop tower water storage tank is connected to the top of the closed-loop water cooling tower through a spray circulation pipe. The outlet is equipped with a nozzle to spray and cool the water coil in the closed-loop water cooling tower. A spray circulation pump is installed on the spray circulation pipe.

9. A method for an independent large circulating water process in an air separation oxygen and nitrogen water precooling system, characterized in that: Based on any one of claims 1 to 8, the air separation oxygen production nitrogen water precooling system water circulation is separated into a large circulating water system, including the water circulation process of the moving equipment and the water circulation process of the nitrogen water precooling system. The water circulation process of the moving equipment involves the circulating water in the closed-loop circulating water tank being pumped and pressurized by the closed-loop circulating water pump and entering the circulating pipe network of the moving equipment. After heat exchange with the coolers and oil coolers of each piece of equipment, the water enters the return water circulating pipe network and is then sent to the heat dissipation pipes of the closed-loop water cooling tower. After cooling, the water collects and falls into the closed-loop circulating water tank.

10. The method for the independent large circulating water process of the air separation oxygen and nitrogen water precooling system according to claim 9, characterized in that, In the nitrogen-water precooling system's water circulation process, after the circulating water in the nitrogen-water precooling circulating water tank is drawn and pressurized by the nitrogen-water precooling circulating water pump, part of it is further pressurized by the nitrogen-water precooling cooling water pump to the middle of the air-cooled tower to conduct counter-current heat exchange and washing with the air for cooling; the other part of the circulating water is supplied to the top of the water-cooled tower to conduct counter-current heat exchange and cooling with the waste nitrogen gas. The water that falls back to the bottom of the water-cooled tower is then pressurized by the nitrogen-water precooling chilled water pump to the top of the air-cooled tower to conduct counter-current heat exchange and washing with the air for cooling.

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