Efficient energy-saving air pretreatment system

Abstract

The invention discloses an efficient energy-saving air pretreatment system, and relates to the technical field of air separation and purification, the efficient energy-saving air pretreatment system comprises a cooling module and a purification module, the cooling module comprises an air cooling tower and a water cooling tower, and a circulating water path is arranged between the water cooling tower and the air cooling tower; the purification module comprises an adsorber, a clean exhaust pipe, a regenerated gas supply pipe and a waste gas exhaust pipe, air enters the purification module after passing through the air cooling tower and then is exhausted from the clean exhaust pipe, regenerated gas enters the adsorber through the regenerated gas supply pipe and then is exhausted through the waste gas exhaust pipe, and the regenerated gas supply pipe is provided with a regeneration heater; and a heat recovery preheater is arranged on the side, located on the upstream side of the regeneration heater, of the regeneration gas supply pipe, a preheating pipeline is arranged between the water outlet end of the air cooling tower and the water cooling tower, and the preheating pipeline passes through the heat recovery preheater, heat of water discharged by the air cooling tower is recycled, and the energy efficiency of the air treatment system is improved.

Description

Technical Field

[0001] This application relates to the field of air separation and purification technology, and more specifically, to a high-efficiency and energy-saving air pretreatment system. Background Technology

[0002] The air pretreatment system is a front-end ambient temperature process in the cryogenic air separation process, comprising an air cooling system and a purification system. The air cooling system cools the high-temperature compressed air before it enters the purification system to remove impurities such as carbon dioxide and water, ensuring the safe operation of subsequent processes. The air cooling system utilizes circulating cooling water to remove heat from the air. The heated circulating cooling water is then cooled by a cooling tower in the circulating water system before re-entering the air cooling system, thus achieving the recycling of the circulating cooling water.

[0003] The purification system utilizes the adsorption properties of adsorbents at room temperature and desorption at high temperature to purify impurities such as carbon dioxide and water from the air. The system is equipped with an adsorber. During purification, the medium passing through the adsorber is cooled air from the air cooling system. The air is dried and purified within the adsorber and then discharged as clean gas. Meanwhile, high-temperature regeneration gas is introduced into the adsorber, regenerating and reactivating the adsorption capacity of the adsorbent, preparing it for the next working cycle.

[0004] The circulating cooling water, carrying the heat exchanged, leaves the air cooling tower and enters the water cooling tower for cooling. This heat is directly wasted, and it also puts significant pressure on the water cooling tower's cooling capacity. Therefore, how to utilize the heat carried by the circulating cooling water and reduce waste is a problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0005] In view of this, the purpose of this application is to provide a high-efficiency and energy-saving air pretreatment system that effectively utilizes the heat of circulating cooling water and improves the energy efficiency of the air handling system.

[0006] To achieve the above objectives, this application provides the following technical solution:

[0007] A high-efficiency and energy-saving air pretreatment system includes a cooling module and a purification module. The cooling module includes an air cooling tower and a cooling water tower, with a circulating water path between the cooling water tower and the air cooling tower. The purification module includes an adsorber, a clean exhaust pipe, a regenerated gas supply pipe, and a waste gas discharge pipe. The air cooling tower has an air inlet and an air outlet for air entry and exit. Air enters the purification module after passing through the air cooling tower and then exits from the clean exhaust pipe. Regenerated gas enters the adsorber through the regenerated gas supply pipe and then exits through the waste gas discharge pipe. The regenerated gas supply pipe is equipped with a regeneration heater, and a heat recovery preheater is provided upstream of the regeneration heater on the regeneration gas supply pipe. A preheating pipeline is provided between the water outlet of the air cooling tower and the cooling water tower, and the preheating pipeline passes through the heat recovery preheater.

[0008] Preferably, the adsorber is provided in multiple ways, the purification module includes multiple branch pipes, a single adsorber is located on one of the branch pipes, the multiple adsorbers are connected in parallel, and each branch pipe is provided with a valve between itself and the air cooling tower, the clean exhaust pipe, the regeneration gas supply pipe and the waste gas discharge pipe.

[0009] Preferably, the working process of the adsorber is a cycle of purification, depressurization, regeneration gas activation, and pressurization. There are two adsors, and the purification and regeneration gas activation processes of the two adsors are performed alternately. During the purification process, air flows from the air cooling tower through the adsorber, and during the regeneration gas activation process, regeneration gas flows through the adsorber.

[0010] Preferably, the regeneration gas activation process includes a heating stage and a cold blowing stage, and water flows through the preheating pipeline only during the heating stage. The preheating pipeline is equipped with a valve.

[0011] Preferably, an auxiliary pipeline connects the outlet of the air cooling tower and the cooling tower, the auxiliary pipeline is connected in parallel with the preheating pipeline, and the auxiliary pipeline is equipped with a valve.

[0012] Preferably, the air flows in the opposite direction to the regeneration gas flowing through the adsorber.

[0013] Preferably, a water inlet pipe is connected between the cooling tower and the air cooling tower, and water enters the air cooling tower from the cooling tower along the water inlet pipe. The water inlet pipe is equipped with a circulation pump and a pressurized refrigeration unit.

[0014] Preferably, two water inlet branch pipes are provided between the water inlet pipe and the air cooling tower, and a spray device is provided at one end of the two water inlet branch pipes that extends into the air cooling tower. The circulating pump and the pressurized refrigeration unit are respectively located on one of the water inlet branch pipes.

[0015] Preferably, the spray device is higher than the air inlet and lower than the air outlet, the spray device connected to the pressurized refrigeration unit is higher than the spray device connected to the circulating pump, and a packing component is provided below the spray device.

[0016] Preferably, a mist eliminator is provided inside the air cooling tower and near the air outlet.

[0017] The high-efficiency and energy-saving air pretreatment system provided in this application involves the gas entering the air cooling tower for cooling. The water discharged from the air cooling tower to the cooling water tower has increased in heat. The water discharged from the air cooling tower is led to the purification module by the preheating pipeline. The regenerated gas is preheated before passing through the regeneration heater, thereby increasing the temperature of the regenerated gas in advance, reducing the pressure on the regeneration heater, and reducing the heat of the water itself to a certain extent. This achieves the purpose of further utilizing heat, improving energy efficiency, and saving energy and reducing emissions. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of this application 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 embodiments of this application. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0019] Figure 1 This is a schematic diagram illustrating the structure of the high-efficiency and energy-saving air pretreatment system in the embodiments of this application;

[0020] Figure 1 In the accompanying drawings, the reference numerals include:

[0021] 1. Air cooling tower; 11. Air compressor; 12. Mist eliminator; 13. Spraying device; 14. Packing components; 15. Preheating pipeline; 2. Cooling tower; 21. Water inlet pipeline; 211. Water inlet branch pipe; 22. Circulating pump; 23. Pressurized refrigeration unit; 24. Auxiliary pipeline; 3. Adsorber; 31. Regeneration heater; 32. Heat recovery preheater; 33. Clean exhaust pipe; 34. Regeneration gas supply pipe; 35. Waste gas discharge pipe; 36. Branch pipeline; 4. Valves. Detailed Implementation

[0022] The technical solutions of 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 application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0023] Unless otherwise defined, the technical or scientific terms used in this application shall have the ordinary meaning understood by one of ordinary skill in the art to which this application pertains. The terms "first," "second," and similar words used in this application do not indicate any order, quantity, or importance. Terms such as "connection" or "linked" are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. Terms such as "upper," "lower," "left," and "right" are used only to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship may also change accordingly. This application discloses a highly efficient and energy-saving air pretreatment system.

[0024] The core of this application is to provide a highly efficient and energy-saving air pretreatment system.

[0025] Please refer to Figure 1 .

[0026] The high-efficiency and energy-saving air pretreatment system provided in this application includes a cooling module and a purification module. The cooling module cools and lowers the temperature of the air to be treated, and the purification module purifies the cooled air by adsorbing and removing impurities such as water and carbon dioxide.

[0027] The cooling module includes an air cooling tower 1 and a cooling water tower 2. The air cooling tower 1 is provided with an air inlet and an air outlet for air to enter and exit. The air inlet is located on the side wall near the bottom, and the air outlet is located at the top of the air cooling tower 1. An air compressor 11 is installed in the air pipe of the air inlet. Under the action of the air compressor 11, the air to be processed is powered to enter the air cooling tower 1.

[0028] A circulating water path is provided between cooling tower 2 and air cooling tower 1. Water circulates between air cooling tower 1 and cooling tower 1. In air cooling tower 1, water absorbs heat from the air to cool it down. In cooling tower 1, water releases heat and becomes cool water again, capable of heat exchange. The outlet of air cooling tower 1 is located at its bottom.

[0029] The purification module includes an adsorber 3, a clean exhaust pipe 33, a regeneration gas supply pipe 34, and a waste gas discharge pipe 35. Air enters the purification module after passing through the air cooling tower 1, passes through the adsorber 3, and is then discharged from the clean exhaust pipe 33. During this process, the adsorber 3 adsorbs and intercepts impurities such as carbon dioxide and water molecules in the air to achieve gas purification.

[0030] The regeneration gas supply pipe 34 is equipped with a regeneration heater 31, which is an electric heater or a steam heater. The regeneration gas passes through the regeneration gas supply pipe 34 and is heated by the regeneration heater 31 before entering the adsorber 3. Then it is discharged through the exhaust gas discharge pipe 35. During this process, the adsorbent in the adsorber 3 is regenerated and activated, preparing for its next air purification work.

[0031] A heat recovery preheater 32 is installed upstream of the regeneration heater 31 on the regeneration gas supply pipe 34. A preheating pipe 15 is installed between the outlet of the air cooling tower 1 and the cooling tower 2. The preheating pipe 15 passes through the heat recovery preheater 32. At the heat recovery preheater 32, the water preheats the regeneration gas passing through it using its own heat. During this process, heat exchange occurs between the water and the regeneration gas. The preheated regeneration gas then enters the regeneration heater 31 for secondary heating. After reaching the regeneration temperature, it provides heat for the adsorbent desorption and activation. The circulating water with recovered heat continues to flow into the cooling tower 2 for further cooling, reducing the pressure on the regeneration heater 31. The heat of the water itself is also reduced to a certain extent, thereby achieving the goal of further utilizing heat, improving energy efficiency, and saving energy and reducing emissions.

[0032] The high-efficiency and energy-saving air pretreatment system provided in this application will be described in more detail below with reference to the accompanying drawings and specific embodiments.

[0033] In one specific implementation, reference is made to... Figure 1 .

[0034] Specifically, there are multiple adsorbers 3, and the purification module includes multiple branch pipes 36. Each adsorber 3 is located on a branch pipe 36, and multiple adsorbers 3 are connected in parallel. Each branch pipe 36 is equipped with a valve 4 between it and the air cooling tower 1, the clean exhaust pipe 33, the regeneration gas supply pipe 34, and the waste gas discharge pipe 35.

[0035] Each adsorber 3 is connected in parallel through branch pipes 36, so the connection between the specific adsorber 3 and the air cooling tower 1, the clean exhaust pipe 33, the regeneration gas supply pipe 34 or the waste gas discharge pipe 35 can be adjusted by controlling the opening and closing of each valve 4. When one part of the adsorber 3 is performing air purification, the other part of the adsorber 3 can be activated by regeneration gas, thereby ensuring that the purification work can be carried out continuously as a whole.

[0036] Specifically, there are two adsorbers 3, and the working process of each adsorber 3 is a cycle of purification, depressurization, regeneration gas activation, and pressurization. The purification and regeneration gas activation processes of the two adsorbers 3 are performed alternately, that is, when one adsorber 3 is performing purification, the other adsorber 3 is performing regeneration gas activation. During the purification process, air flows from the air cooling tower 1 through the adsorber 3 and is discharged through the clean exhaust pipe 33; during the regeneration gas activation, the regeneration gas flows through the adsorber 3 and is finally discharged through the waste gas exhaust pipe 35.

[0037] Specifically, the regeneration gas activation process includes a heating stage and a cold blowing stage. Water flows through the preheating pipeline 15 only during the heating stage to perform the corresponding preheating work. Therefore, the preheating pipeline 15 is equipped with a valve 4, which is opened only when any one of the adsorbers 3 is in the heating stage of regeneration gas activation.

[0038] Based on the above embodiments, refer to Figure 1 .

[0039] Specifically, an auxiliary pipe 24 connects the outlet of the air cooling tower 1 and the cooling tower 2. The auxiliary pipe 24 is connected in parallel with the preheating pipe 15, and a valve 4 is installed on the auxiliary pipe 24. When the valve 4 on the preheating pipe 15 is closed, the valve 4 on the auxiliary pipe 24 is opened, allowing water leaving the air cooling tower 1 to directly enter the cooling tower 2. The water circulation cooling process is stable, continuous, and uninterrupted.

[0040] Based on any of the above embodiments, refer to Figure 1 .

[0041] Specifically, in order to improve the activation effect of the regeneration gas in the adsorber 3, the air flow direction through the adsorber 3 is opposite to the regeneration gas flow direction through the adsorber 3.

[0042] Based on any of the above embodiments, refer to Figure 1 .

[0043] Specifically, a water inlet pipe 21 connects the cooling tower 2 and the air cooling tower 1, allowing water to flow from the cooling tower 2 into the air cooling tower 1 via the water inlet pipe 21. The water inlet pipe 21 is equipped with a circulating pump 22 and a pressurized refrigeration unit 23. The circulating pump 22 provides flow power to the water, while the pressurized refrigeration unit 23 further cools the water while also providing flow power.

[0044] Based on the above embodiments, refer to Figure 1 .

[0045] Specifically, the air cooling tower 1 is a two-stage cooling tower. Two inlet branch pipes 211 are installed between the inlet pipe 21 and the air cooling tower 1. The circulating pump 22 and the booster refrigeration unit 23 are each located on one inlet branch pipe 211, meaning they are connected in parallel. A spray device 13 is installed at one end of each of the two inlet branch pipes 211 that extends into the air cooling tower 1. The spray device 13 is located within the height difference between the air inlet and outlet, and the spray direction is downward.

[0046] The spray device 13 connected to the pressurized refrigeration unit 23 is higher than the spray device 13 connected to the circulating pump 22. The inner wall of the air cooling tower 1 is fixedly provided with packing parts 14 below the two spray devices 13 to increase the contact rate between water and air and improve the cooling efficiency.

[0047] To prevent free water from being carried into the purification module and increasing the difficulty of adsorption, a mist eliminator 12 is fixedly installed inside the air cooling tower 1 and near the air outlet to intercept free water in the gas passing through.

[0048] Application Example: A typical 60,000 Nm³ / h external compressed air separator has an air processing capacity of 300,000 Nm³ / h, a regeneration gas flow rate of 60,000 Nm³ / h, an oxygen product flow rate of 60,000 Nm³ / h, and a nitrogen product flow rate of 120,000 Nm³ / h. After implementing this solution, energy consumption during the regeneration heating stage is reduced by 480 kW, average regeneration energy consumption is reduced by 190 kW, regeneration resistance increases by 2 kPa, air compressor discharge pressure increases by 6 kPa, product gas compressor inlet pressure increases by 2 kPa, overall compressor energy consumption increases by 20 kW, and the average energy consumption of the circulating pump 22 in air cooling tower 1 decreases by 20 kW, resulting in a total energy saving of 190 kW. Equipment and pipeline investment increases by 400,000 yuan. Based on an electricity price of 0.6 yuan / kWh and an annual continuous operating time of 8,000 hours, the investment payback period is 6 months.

[0049] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0050] The above provides a detailed description of a high-efficiency and energy-saving air pretreatment system provided in this application. Specific examples have been used to illustrate the principles and implementation methods of this application. The descriptions of the embodiments above are merely for the purpose of helping to understand the method and core ideas of this application. It should be noted that those skilled in the art can make various improvements and modifications to this application without departing from its principles, and these improvements and modifications also fall within the protection scope of this application.

Claims

1. A high-efficiency and energy-saving air pretreatment system, characterized in that, The system includes a cooling module and a purification module. The cooling module includes an air cooling tower (1) and a cooling water tower (2), with a circulating water path between the cooling water tower (2) and the air cooling tower (1). The purification module includes an adsorber (3), a clean exhaust pipe (33), a regeneration gas supply pipe (34), and a waste gas discharge pipe (35). The air cooling tower (1) has an air inlet and an air outlet for air to enter and exit. Air enters the purification module after passing through the air cooling tower (1) and then exits through the clean exhaust pipe (33). The regenerated gas enters the adsorber (3) through the regenerated gas supply pipe (34) and is discharged through the exhaust gas discharge pipe (35). The regenerated gas supply pipe (34) is equipped with a regenerated heater (31), and a heat recovery preheater (32) is provided on the upstream side of the regenerated heater (31) of the regenerated gas supply pipe (34). A preheating pipeline (15) is provided between the water outlet of the air cooling tower (1) and the cooling tower (2), and the preheating pipeline (15) passes through the heat recovery preheater (32).

2. The high-efficiency energy-saving air pretreatment system according to claim 1, characterized in that, The adsorber (3) is provided in multiple ways. The purification module includes multiple branch pipes (36). Each adsorber (3) is located on one branch pipe (36). Multiple adsorbers (3) are connected in parallel. Each branch pipe (36) is provided with a valve (4) between itself and the air cooling tower (1), the clean exhaust pipe (33), the regeneration gas supply pipe (34), and the waste gas discharge pipe (35).

3. The high-efficiency energy-saving air pretreatment system according to claim 2, characterized in that, The working process of the adsorber (3) is a cycle of purification work - depressurization - regeneration gas activation - pressurization. There are two adsorbers (3). The purification work and regeneration gas activation processes of the two adsorbers (3) are carried out alternately. In the purification work, air flows from the air cooling tower (1) through the adsorber (3). In the regeneration gas activation, regeneration gas flows through the adsorber (3).

4. The high-efficiency energy-saving air pretreatment system according to claim 3, characterized in that, The regeneration gas activation process includes a heating stage and a cold blowing stage. Water flows through the preheating pipeline (15) only during the heating stage. The preheating pipeline (15) is equipped with a valve (4).

5. The high-efficiency energy-saving air pretreatment system according to claim 4, characterized in that, An auxiliary pipeline (24) is connected between the outlet of the air cooling tower (1) and the cooling tower (2). The auxiliary pipeline (24) and the preheating pipeline (15) are connected in parallel. The auxiliary pipeline (24) is equipped with a valve (4).

6. The high-efficiency energy-saving air pretreatment system according to any one of claims 2-5, characterized in that, The air flows in the opposite direction to the regenerated gas as it flows through the adsorber (3).

7. The high-efficiency energy-saving air pretreatment system according to any one of claims 1-5, characterized in that, A water inlet pipe (21) is connected between the cooling tower (2) and the air cooling tower (1). Water enters the air cooling tower (1) from the cooling tower (2) along the water inlet pipe (21). The water inlet pipe (21) is equipped with a circulation pump (22) and a pressurized refrigeration unit (23).

8. The high-efficiency energy-saving air pretreatment system according to claim 7, characterized in that, Two water inlet branch pipes (211) are provided between the water inlet pipe (21) and the air cooling tower (1). A spray device (13) is provided at one end of the two water inlet branch pipes (211) that extends into the air cooling tower (1). The circulating pump (22) and the pressurized refrigeration unit (23) are respectively located on one of the water inlet branch pipes (211).

9. The high-efficiency energy-saving air pretreatment system according to claim 8, characterized in that, The spray device (13) is higher than the air inlet and lower than the air outlet. The spray device (13) connected to the pressurized refrigeration unit (23) is higher than the spray device (13) connected to the circulating pump (22). A packing element (14) is provided below the spray device (13).

10. The high-efficiency energy-saving air pretreatment system according to claim 9, characterized in that, A mist trap (12) is provided inside the air cooling tower (1) and near the air outlet.

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