A waste gas recycling system of an air separation device

Abstract

This invention provides a waste gas recovery and utilization system for an air separation unit, including a waste gas recovery tank and a circulating water cooling tower. The waste gas recovery tank has a waste gas recovery port at its lower end and a waste gas exhaust port at its upper end. The circulating water cooling tower has a circulating water return port on one side of its upper end. Multiple return water spray heads communicating with the circulating water return port are located inside the upper part of the circulating water cooling tower. A water storage tank is located inside the lower end of the circulating water cooling tower. A waste gas inlet communicating with the waste gas exhaust port is located on one side of the middle part of the circulating water cooling tower. A horizontally arranged waste gas injection pipe communicating with the waste gas inlet is also located above the water storage tank inside the circulating water cooling tower. Multiple waste gas ejection holes are located at the upper end of the waste gas injection pipe. Multiple exhaust fans are located at the top of the circulating water cooling tower. This invention has a simple structure and can recover and reuse waste gas, greatly saving energy consumption of the circulating water cooling tower.

Description

Technical Field

[0001] This utility model relates to the field of air separation equipment, and in particular to a waste gas recovery and utilization system for air separation equipment. Background Technology

[0002] Air separation units generate waste gases during production, primarily consisting of air, nitrogen, oxygen, and waste nitrogen. These waste gases typically exhibit the following characteristics: 1. Large volume: The air separation unit has a large production scale and produces a relatively large amount of waste gas.

[0003] 2. Relatively stable composition: Although the main components are nitrogen, argon and oxygen, the composition is stable.

[0004] 3. Relatively stable pressure and temperature: Exhaust gas is usually under a certain pressure and temperature, and the temperature does not change too much.

[0005] 4. Drying property: After air passes through the molecular sieve for adsorption, it retains its drying property.

[0006] In the air separation heat exchange process: compressed air generates a large amount of heat, which is exchanged with circulating water in the heat exchanger. The high-temperature fluid transfers heat to the circulating water, raising its temperature. The circulating water then carries the heat away and returns to the circulating water pool, where it is cooled by the cooling tower.

[0007] The circulating water heat exchange system continuously lowers the temperature of the circulating water through a cooling tower fan, thereby ensuring that the air separation equipment operates within a suitable temperature range. If the circulating water is not cooled in time, it will lead to excessively high compressor exhaust temperature, increasing the gas compression ratio, increasing energy consumption, and greatly affecting its working efficiency and lifespan. If the oil temperature is not cooled, an oil film cannot be formed, leading to malfunctions in the compressor lubrication system. Therefore, the temperature of the circulating water is extremely important.

[0008] There are many types of waste gas released by air separation: large quantities include molecular sieve regeneration gas, nitrogen, oxygen released from the cold box, and air released from oxygen compressors and nitrogen compressors. The waste gas is generated through process separation, which requires a certain amount of energy. If this part of the waste gas can be recycled and reused, it will be of great benefit to energy conservation. Utility Model Content To address the problem that waste gas generated during the production process of air separation units in existing technologies cannot be recovered and reused, this utility model provides a waste gas recovery and reuse system for air separation units that uses waste gas to cool circulating water.

[0009] This utility model provides a waste gas recovery and utilization system for an air separation unit, including a waste gas recovery tank and a circulating water cooling tower. The waste gas recovery tank has a waste gas recovery port at its lower end and a waste gas exhaust port at its upper end. The circulating water cooling tower has a circulating water return port on one side of its upper end. The circulating water cooling tower has multiple return water spray heads connected to the circulating water return port inside its upper end. The circulating water cooling tower has a water storage tank inside its lower end. The circulating water cooling tower has a waste gas inlet on one side of its middle section connected to the waste gas exhaust port. The circulating water cooling tower also has a horizontally arranged waste gas injection pipe above the water storage tank, which is connected to the waste gas inlet. The waste gas injection pipe has multiple waste gas ejection holes at its upper end. The circulating water cooling tower has multiple exhaust fans at its top.

[0010] As a further improvement of this utility model, a circulating water supply port is provided on one side of the lower end of the circulating water cooling tower.

[0011] As a further improvement of this utility model, the waste gas recovery tank is also equipped with a temperature sensor and a first pressure sensor at the waste gas recovery port.

[0012] As a further improvement of this utility model, a second pressure sensor is also provided on the waste gas recovery tank at the waste gas exhaust port.

[0013] As a further improvement of this utility model, the waste gas recovery port and the waste gas exhaust port are respectively equipped with switch valves.

[0014] As a further improvement of this utility model, the circulating water return port, the exhaust gas inlet and the circulating water supply port are each equipped with control valves.

[0015] As a further improvement of this utility model, a sewage pipe communicating with the water storage tank is provided on one side of the bottom of the water storage tank, and the sewage pipe is equipped with a sewage valve.

[0016] The beneficial effects of this utility model are: this utility model has a simple structure, can recycle and reuse waste gas, and greatly saves the energy consumption of the circulating water cooling tower. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the structure of the waste gas recovery tank of a waste gas recovery and utilization system for an air separation unit according to this utility model; Figure 2 This is a schematic diagram of the internal structure of the circulating water cooling tower of an air separation unit's waste gas recovery and utilization system according to this utility model.

[0018] Attached reference numerals: 11-Waste gas recovery tank; 12-Waste gas recovery port; 13-Waste gas exhaust port; 14-Temperature sensor; 15-First pressure sensor; 16-Second pressure sensor; 21-Circulating water cooling tower; 22-Circulating water return port; 23-Waste gas inlet; 24-Waste gas injection pipe; 25-Water storage tank; 26-Circulating water supply port; 27-Sewage pipe; 28-Exhaust fan. Detailed Implementation

[0019] In the description of this utility model, it should be understood that if there are descriptions involving orientation, such as up, down, front, back, left, right, etc., indicating orientation or positional relationship, the orientation description may be based on the orientation or positional relationship shown in the accompanying drawings. This is only for the convenience of describing this utility model and simplifying the description, and is not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation of this utility model.

[0020] In the description of this utility model, if there is a description of quantity, "several" means one or more, "more than" means two or more, "greater than," "less than," "exceeding," etc. are understood to exclude the number itself, while "above," "below," "within," etc. are understood to include the number itself. If there is a description of "first" or "second," it is only for the purpose of distinguishing technical features and should not be construed as indicating or implying relative importance or implicitly indicating the number of indicated technical features or the order of the indicated technical features.

[0021] In the description of this utility model, unless otherwise explicitly defined, terms such as "setting," "installation," and "connection" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this utility model in conjunction with the specific content of the technical solution.

[0022] like Figure 1 and Figure 2 As shown, this utility model discloses a waste gas recovery and utilization system for an air separation unit, including a waste gas recovery tank and a circulating water cooling tower 21. The waste gas recovery tank 11 has a waste gas recovery port 12 at its lower end and a waste gas exhaust port 13 at its upper end. The circulating water cooling tower 21 has a circulating water return port 22 on one side of its upper end. The circulating water cooling tower 21 has multiple return water spray heads connected to the circulating water return port 22 inside its upper end. The circulating water cooling tower 21 has a water storage tank 25 inside its lower end. The circulating water cooling tower 21 has a waste gas inlet 23 connected to the waste gas exhaust port 13 on one side of its middle section. The circulating water cooling tower 21 also has a horizontally arranged waste gas injection pipe 24 above the water storage tank 25 and connected to the waste gas inlet 23. The waste gas injection pipe 24 has multiple waste gas ejection holes at its upper end. The circulating water cooling tower has multiple exhaust fans at its top.

[0023] During operation, the exhaust gas generated by the air separation unit enters the exhaust gas recovery tank 11 through the exhaust gas recovery port 12 for storage. The exhaust gas outlet 13 is connected to the circulating water cooling tower 21. The circulating water returning from the air separation unit after heat exchange is at approximately 45 degrees Celsius. It flows downwards through the circulating water return port 22 and is sprayed downwards by the return water spray head. Meanwhile, the exhaust gas temperature in the exhaust gas recovery tank 11 is approximately 27 degrees Celsius, and it is sprayed upwards through the exhaust gas outlet and flows upwards under the action of the exhaust fan. This downward-flowing return water comes into contact with the upward-flowing air-exhaust gas mixture, achieving heat conduction and heat exchange. On one hand, because the temperature of the return water is higher than that of the exhaust gas, heat is directly transferred from the water to the exhaust gas, cooling the water. On the other hand, because the exhaust gas is relatively dry, with a relative humidity of only about 30%, water molecules can continuously evaporate and diffuse into the exhaust gas. Water evaporation requires the absorption of latent heat of vaporization, carrying away heat from the water and continuously lowering its temperature. This effectively cools the circulating water. To ensure the cooling effect of the subsequent circulating water on the air separation unit.

[0024] There is a distance between the lower end of the circulating water cooling tower and the upper end of the water storage tank, which serves as the suction space for the top exhaust fan. When the exhaust fan is running, it simultaneously draws in air and exhaust gas. The airflow from bottom to top and the return water from top to bottom undergo countercurrent heat exchange to achieve heat exchange, reduce the temperature of the circulating water, and the exhaust gas is safely discharged from the top of the exhaust fan into the atmosphere.

[0025] Cooling circulating water with exhaust gas is not only simple and convenient, but also greatly saves on the cooling cost of circulating water.

[0026] In this invention, a circulating water supply port 26 is provided on one side of the lower end of the circulating water cooling tower 21, and the cooled circulating water continues to participate in the water cooling operation of the air separation unit.

[0027] In this invention, a temperature sensor 14 and a first pressure sensor 15 are also provided on the waste gas recovery tank 11 at the waste gas recovery port 12; a second pressure sensor 16 is also provided on the waste gas recovery tank 11 at the waste gas exhaust port 13. These are used for monitoring the pressure and temperature inside the tank.

[0028] In this invention, the waste gas recovery port 12 and waste gas exhaust port 13 are each equipped with a switch valve, and the circulating water return port 22, waste gas inlet, and circulating water supply port 26 are each equipped with a control valve. These are used for controlling the opening and closing of the pipeline. In this invention, a sewage pipe 27 communicating with the water storage tank 25 is provided on one side of the bottom of the water storage tank 25, and the sewage pipe 27 is equipped with a sewage discharge valve. Wastewater used for daily maintenance is discharged.

[0029] This utility model has a simple structure and can recycle and reuse waste gas, which greatly saves the energy consumption of the circulating water cooling tower 21.

[0030] The above description, in conjunction with specific preferred embodiments, provides a further detailed explanation of the present invention. It should not be construed that the specific implementation of the present invention is limited to these descriptions. For those skilled in the art, various simple deductions or substitutions can be made without departing from the concept of the present invention, and all such modifications and substitutions should be considered within the protection scope of the present invention.

Claims

1. A waste gas recovery and utilization system for an air separation unit, characterized in that: The system includes an exhaust gas recovery tank and a circulating water cooling tower. The exhaust gas recovery tank has an exhaust gas recovery port at its lower end and an exhaust gas exhaust port at its upper end. The circulating water cooling tower has a circulating water return port on one side of its upper end. The circulating water cooling tower has multiple return water spray heads connected to the circulating water return port inside its upper end. The circulating water cooling tower has a water storage tank at its lower bottom and an exhaust gas inlet connected to the exhaust gas exhaust port on one side of its lower part. The circulating water cooling tower also has a horizontally arranged exhaust gas injection pipe connected to the exhaust gas inlet above the water storage tank. The exhaust gas injection pipe has multiple exhaust gas ejection holes at its upper end. The circulating water cooling tower has multiple exhaust fans at its top.

2. The waste gas recovery and utilization system of the air separation unit according to claim 1, characterized in that: The circulating water cooling tower is provided with a circulating water supply port on one side of its lower end.

3. The waste gas recovery and utilization system of the air separation unit according to claim 1, characterized in that: The waste gas recovery tank is also equipped with a temperature sensor and a first pressure sensor at the waste gas recovery port.

4. The waste gas recovery and utilization system of the air separation unit according to claim 3, characterized in that: The waste gas recovery tank is also equipped with a second pressure sensor located at the waste gas exhaust port.

5. The waste gas recovery and utilization system of the air separation unit according to claim 1, characterized in that: The waste gas recovery port and the waste gas exhaust port are each equipped with a switch valve.

6. The waste gas recovery and utilization system of the air separation unit according to claim 1, characterized in that: The circulating water return port, the exhaust gas inlet, and the circulating water supply port are each equipped with control valves.

7. The waste gas recovery and utilization system of the air separation unit according to claim 1, characterized in that: A sewage pipe connected to the bottom of the water storage tank is provided on one side, and the sewage pipe is equipped with a sewage valve.

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