CN210764337U - A negative pressure adsorption high-purity nitrogen making device - Google Patents

Abstract

The utility model relates to a field of nitrogen making equipment discloses a high-purity nitrogen making device is adsorbed to negative pressure, including nitrogen gas house steward, voltage-sharing lower extreme house steward, oxygen boosting house steward, air house steward, voltage-sharing upper end house steward, nitrogen gas vacuum pump, nitrogen gas booster compressor, oxygen boosting vacuum pump and four adsorption towers. An adsorbent is arranged in the adsorption tower. Each adsorption tower is communicated with a nitrogen main pipe, a pressure-equalizing lower end main pipe, an oxygen-enriched main pipe, an air main pipe and a pressure-equalizing upper end main pipe through a control valve. The nitrogen vacuum pump and the nitrogen booster compressor are both connected in series to the nitrogen header pipe, and the oxygen-enriched vacuum pump is connected to the oxygen-enriched header pipe. After the air enters the adsorption tower, oxygen and other gases are adsorbed, and negative pressure is formed in the adsorption tower. Meanwhile, the nitrogen booster also enables negative pressure to be formed in the adsorption tower. These all make this device can absorb air by oneself, and need not send the air into the adsorption tower through auxiliary assembly, have simplified the structure, have reduced the energy consumption simultaneously. In addition, oxygen-enriched gas can be obtained and collected during desorption.

Description

A negative pressure adsorption high-purity nitrogen making device

technical field

The utility model relates to the field of nitrogen producing equipment, in particular to a negative pressure adsorption high-purity nitrogen producing device.

Background technique

Pressure swing adsorption nitrogen production uses air as raw material, and uses a high-efficiency, high-selectivity solid adsorbent to selectively adsorb nitrogen and oxygen to separate nitrogen and oxygen in the air. The separation effect of carbon molecular sieve on nitrogen and oxygen is mainly based on the different diffusion rates of these two gases on the surface of carbon molecular sieve, oxygen diffuses faster, and more enters the solid phase of molecular sieve. In this way, a nitrogen-enriched component can be obtained in the gas phase. After a period of time, the adsorption of oxygen by molecular sieve reaches equilibrium. According to the different characteristics of carbon molecular sieve on the adsorption amount of adsorbed gas under different pressures, reducing the pressure makes carbon molecular sieve desorb oxygen. This process is called regeneration. The pressure swing adsorption method usually uses two towers in parallel, alternating pressurized adsorption and decompression regeneration, so as to obtain a continuous nitrogen flow.

Pressure swing adsorption nitrogen generator (referred to as PSA nitrogen generator) is a nitrogen generator designed and manufactured according to pressure swing adsorption technology. It is mainly composed of air compressor, adsorption tower, program-controlled valve and compression device. The outlet pressure of the compressor is 0.65-0.8MPaG, usually two adsorption towers are connected in parallel, and the sequence is strictly controlled by the automatic control system according to a specific programmable program, and the pressure adsorption and decompression regeneration are alternately carried out to complete the separation of nitrogen and oxygen to obtain the required high purity. of nitrogen.

The pressure swing adsorption nitrogen generator in the prior art can only produce nitrogen, and has a single function; at the same time, the structure is complex and the energy consumption is high, and the purity of the nitrogen produced is low.

Utility model content

The purpose of the utility model is to provide a negative pressure adsorption high-purity nitrogen making device, which can produce high-purity nitrogen and oxygen-rich, and at the same time has a simple structure and low energy consumption.

The embodiment of the present utility model is realized in this way:

A negative pressure adsorption high-purity nitrogen making device is characterized in that: it comprises a nitrogen main pipe, an equal pressure lower end main pipe, an oxygen-enriched main pipe, an air main pipe, an equal pressure upper end main pipe, a nitrogen vacuum pump, a nitrogen booster, an oxygen-enriched vacuum pump and four an adsorption tower; an adsorbent is arranged in the adsorption tower;

The bottom end of each adsorption tower is connected to the air main pipe through an air inlet pipe, and the top end of each adsorption tower is connected to the nitrogen main pipe through an air outlet pipe; each air inlet pipe is provided with an air control valve, each The gas outlet pipes are all provided with nitrogen control valves;

Each of the gas outlet pipes is connected with a pressure equalizing upper branch pipe between the corresponding adsorption tower and the nitrogen control valve; the pressure equalizing upper branch pipes are all connected to the pressure equalizing upper main pipe, and each of the pressure equalizing upper branch pipes is provided with a pressure equalizing upper end control valve; the pressure equalizing upper end main pipe is connected to the nitrogen main pipe; the end of the pressure equalizing upper main pipe close to the nitrogen main pipe is provided with a final rise master control valve;

Each of the intake pipes is connected with an oxygen-enriched branch pipe and a pressure equalizing lower-end branch pipe between the corresponding adsorption tower and the air control valve; the oxygen-enriched branch pipes are all connected with the oxygen-enriched main pipe, and each of the oxygen-enriched branch pipes is provided with an oxygen-enriched control valve; the pressure-equalizing lower-end branch pipes are all connected to the pressure-equalizing lower-end main pipe, and each of the pressure-equalizing lower-end branch pipes is provided with a pressure-equalizing lower-end control valve;

The nitrogen vacuum pump and the nitrogen booster are connected in series with the nitrogen main pipe, so that the nitrogen produced by the four adsorption towers can be discharged through the nitrogen vacuum pump and the nitrogen booster;

The oxygen-enriched vacuum pump is connected to the oxygen-enriched main pipe, so that the oxygen-enriched oxygen desorbed by the four adsorption towers can be discharged through the oxygen-enriched vacuum pump.

Further, the nitrogen main pipe is also provided with a nitrogen buffer tank, so that the nitrogen produced by the four adsorption towers can pass through the nitrogen buffer tank and then be discharged through a nitrogen vacuum pump and a nitrogen booster; the oxygen-enriched main pipe is also provided with There is an oxygen-enriched buffer tank, so that the oxygen-enriched oxygen desorbed by the four adsorption towers can pass through the oxygen-enriched buffer tank and then be discharged through the oxygen-enriched vacuum pump.

Further, the air intake end of the air main pipe is provided with a filter screen.

Further, the bottom layer of the adsorption tower is equipped with alumina or silica gel or 3A molecular sieve; the upper layer of the adsorption tower is equipped with carbon molecular sieve.

Further, the oxygen enrichment control valve, nitrogen control valve, pressure equalization lower end control valve, pressure equalization upper end control valve, final lift master control valve and air control valve are all controlled by PLC or DCS.

Further, the number of the pressure-equalizing lower-end manifold is one; each of the adsorption towers is connected to the equal-pressure lower-end manifold.

Further, a standby adsorption tower is also included; the standby adsorption tower is connected in parallel with the four adsorption towers.

The beneficial effects of the present utility model are:

After the air enters the adsorption tower, oxygen and other gases are adsorbed by the nitrogen-making adsorbent, and only nitrogen passes through the adsorption tower. Since oxygen in the air occupies 21%, a large amount of gas is adsorbed by the nitrogen-producing adsorbent, which causes a large negative pressure in the adsorption tower, so that the air is sucked into the adsorption tower under the action of negative pressure. At the same time, the nitrogen vacuum pump compresses and discharges the nitrogen, which will also form a negative pressure in the adsorption tower. All of these make the pressure swing adsorption device for nitrogen production by negative pressure adsorption of the present invention to absorb air by itself, without sending air into the adsorption tower through auxiliary equipment such as a blower, which simplifies the structure and reduces energy consumption.

The negative pressure adsorption high-purity nitrogen making device of the utility model has a negative pressure in the adsorption tower, which helps the nitrogen making adsorbent to adsorb non-product gases, so that the adsorption effect is better, and the purity of the nitrogen produced is improved. higher.

In addition, the negative pressure adsorption high-purity nitrogen making device of the utility model can obtain and collect oxygen-enriched gas during desorption, so that two products can be produced at one time.

Description of drawings

In order to illustrate the technical solutions of the embodiments of the present invention more clearly, the accompanying drawings that need to be used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention. Therefore, it should not be regarded as a limitation of the scope. For those of ordinary skill in the art, other related drawings can also be obtained from these drawings without any creative effort.

Fig. 1 is the schematic diagram of the utility model;

Figure 2 is a schematic diagram of the utility model setting up a standby adsorption tower.

Icons: 1- Air main pipe, 11- Intake pipe, 111- Air control valve, 12- Filter screen, 2- Nitrogen main pipe, 21- Air outlet pipe, 211- Nitrogen control valve, 22- Nitrogen buffer tank, 3- Oxygen rich main pipe , 31-Oxygen-enriched branch pipe, 311-Oxygen-enriched control valve, 32-Oxygen-enriched buffer tank, 4-Equal pressure lower end header, 41-Equal pressure lower end branch pipe, 411-Equal pressure lower end control valve, 5-Equal pressure upper end header, 51- Pressure equalizing upper branch pipe, 511- Pressure equalizing upper control valve, 52- Final liter master control valve, 6- Nitrogen vacuum pump, 7- Nitrogen booster, 8- Oxygen-enriched vacuum pump, 9- Adsorption tower, 91- Standby adsorption tower.

Detailed ways

In order to make the purposes, technical solutions and advantages of the embodiments of the present utility model clearer, the technical solutions in the embodiments of the present utility model will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present utility model. The embodiments described above are a part of the embodiments of the present invention, but not all of the embodiments. The components of the embodiments of the invention generally described and illustrated in the drawings herein may be arranged and designed in a variety of different configurations.

Accordingly, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the invention as claimed, but is merely representative of selected embodiments of the invention. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the protection scope of the present invention.

It should be noted that like numerals and letters refer to like items in the following figures, so once an item is defined in one figure, it does not require further definition and explanation in subsequent figures.

In the description of the present invention, it should also be noted that, unless otherwise expressly specified and limited, the terms "arrangement", "installation", "connection" and "connection" should be understood in a broad sense, for example, it may be a fixed connection , or detachable connection, or integral connection; direct connection, indirect connection through an intermediate medium, or internal communication between two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood in specific situations.

Example:

Referring to FIG. 1, the present embodiment provides a negative pressure adsorption high-purity nitrogen making device, including a nitrogen manifold 2, a pressure equalizing lower manifold 4, an oxygen-enriching manifold 3, an air manifold 1, an equalizing upper manifold 5, a nitrogen vacuum pump 6, Nitrogen booster 7, oxygen-enriched vacuum pump 8 and four adsorption towers 9. The bottom of the adsorption tower 9 is provided with a desiccant, which can be silica gel or alumina or 3A molecular sieve, for adsorbing moisture and carbon dioxide; the upper part of the adsorption tower 9 is provided with a carbon molecular sieve for adsorbing oxygen.

The bottom end of each adsorption tower 9 is connected to the air main pipe 1 through the air inlet pipe 11 , and the top end of each adsorption tower 9 is connected to the nitrogen main pipe 2 through the air outlet pipe 21 . Each air inlet pipe 11 is provided with an air control valve 111 for controlling the entry of air into the adsorption tower 9 , and each air outlet pipe 21 is provided with a nitrogen control valve 211 for controlling nitrogen gas discharge from the adsorption tower 9 .

Each gas outlet pipe 21 is connected with a pressure equalizing upper branch pipe 51 between the corresponding adsorption tower 9 and the nitrogen control valve 211 . The pressure equalizing upper branch pipes 51 are all connected to the pressure equalizing upper main pipe 5 , and each pressure equalizing upper branch pipe 51 is provided with a pressure equalizing upper control valve 511 for pressure equalization. The pressure equalizing upper end header 5 is connected to the nitrogen header 2 . A final lift master control valve 52 is provided at one end of the pressure equalizing upper end manifold 5 close to the nitrogen manifold 2 .

Each intake pipe 11 is connected with an oxygen-enriching branch pipe 31 and a pressure equalizing lower-end branch pipe 41 between the corresponding adsorption tower 9 and the air control valve 111 . The oxygen-enriched branch pipes 31 are all connected to the oxygen-enriched main pipe 3 , and each oxygen-enriched branch pipe 31 is provided with an oxygen-enriched control valve 311 for controlling the discharge of oxygen-enriched gas from the adsorption tower 9 . The pressure-equalizing lower-end branch pipes 41 are all connected to the pressure-equalizing lower-end main pipe 4, and each pressure-equalizing lower-end branch pipe 41 is provided with a pressure-equalizing lower-end control valve 411 . When the pressure-equalizing lower-end control valve 411 and the pressure-equalizing upper-end control valve 511 of the two adsorption towers 9 connected to the same pressure-equalizing lower-end main pipe 4 and the same pressure-equalizing upper-end main pipe 5 are both opened, the air pressure in the two adsorption towers 9 gradually passes through the equalization pressure. The lower end header 4 and the pressure equalizing upper header 5 are adjusted to be the same.

The nitrogen vacuum pump 6 and the nitrogen booster 7 are connected in series with the nitrogen main pipe 2 , so that the nitrogen produced by the four adsorption towers 9 can be discharged through the nitrogen vacuum pump 6 and the nitrogen booster 7 . The nitrogen main pipe 2 is also provided with a nitrogen buffer tank 22 , so that the nitrogen produced by the four adsorption towers 9 can pass through the nitrogen buffer tank 22 and then be discharged through the nitrogen vacuum pump 6 and the nitrogen booster 7 .

The oxygen-enriched vacuum pump 8 is connected to the oxygen-enriched main pipe 3 , so that the oxygen-enriched oxygen desorbed by the four adsorption towers 9 can be discharged through the oxygen-enriched vacuum pump 8 . The oxygen-enriched main pipe 3 is also provided with an oxygen-enriched buffer tank 32 , so that the oxygen-enriched oxygen desorbed by the four adsorption towers 9 can pass through the oxygen-enriched buffer tank 32 and then be discharged through the oxygen-enriched vacuum pump 8 .

The four adsorption towers 9 of the negative pressure adsorption high-purity nitrogen making device of the present invention are respectively adsorption tower A, adsorption tower B, adsorption tower C and adsorption tower D. In this embodiment, the entire nitrogen production process sequence process and the mutual cooperation of the two adsorption towers 9 are described by taking the adsorption tower A and the adsorption tower B as examples. The technical process and mutual cooperation of adsorption tower C and adsorption tower D are the same as the technical process and mutual cooperation of adsorption tower A and adsorption tower B. The time sequence control diagram of the present utility model is shown in Table 1. In Table 1, A stands for adsorption, ED stands for equal pressure drop, W stands for waiting, VC stands for vacuum, ER stands for equal pressure rise, and FR stands for final pressure rise.

Table 1

Steps 1 to 4, adsorption tower A adsorption, adsorption tower B desorption: control the raw gas (air) from the air main pipe 1 and the intake pipe 11 to enter the adsorption tower A for adsorption, and the obtained nitrogen enters the nitrogen gas through the gas outlet pipe 21 and the nitrogen main pipe 2 Buffer tank 22; under the action of the nitrogen vacuum pump 6, the nitrogen in the nitrogen buffer tank 22 is sent to the nitrogen booster 7 to be compressed to the set pressure and then delivered to the user. After the adsorption tower 9A is saturated, the adsorption is stopped. During the adsorption process of adsorption tower A, adsorption tower B desorbs. During this process, the oxygen-enriched vacuum pump 8 evacuates the adsorption tower B, so that the adsorption tower B is desorbed. The oxygen-rich oxygen obtained by desorption of adsorption tower B is drawn out from the bottom of adsorption tower 9, and is boosted to a slightly positive pressure by oxygen-rich vacuum pump 8 and sent to the user.

Steps 5 and 6, the pressure drop of the adsorption tower A, and the pressure rise of the adsorption tower B: at this time, the pressure equalization lower end control valve 411 of the adsorption tower A, the pressure equalization upper end control valve 511 and the pressure equalization lower end control valve of the adsorption tower B 411. Both the pressure equalizing upper end control valves 511 are opened. The adsorption tower A and the adsorption tower B are connected through the pressure-equalizing lower-end header 4 and the pressure-equalizing upper-end header 5, so that the air pressure in the adsorption tower A gradually decreases and the air pressure in the adsorption tower B gradually increases, so that the two air pressures are basically the same.

In steps 7 and 8, the adsorption tower A waits, and the final pressure of the adsorption tower B rises. During this process, both the pressure equalizing upper end control valve 511 of the adsorption tower B and the final lift master control valve 52 of the pressure equalizing upper end header 5 are both opened. Since the air pressure in the adsorption tower B is still low, the nitrogen produced by the other adsorption towers 9 is sucked into the adsorption tower B, so that the air pressure in the adsorption tower B continues to rise.

Steps 9 to 12, the adsorption tower A is evacuated, and the adsorption tower B is adsorbed. Since the adsorption tower A begins to be evacuated, the adsorbent in the adsorption tower A is gradually desorbed as the air pressure in the adsorption tower A gradually decreases. The oxygen-enriched gas desorbed from the adsorption tower A is drawn out from the bottom of the adsorption tower 9, and is boosted to a slightly positive pressure by the oxygen-enriched vacuum pump 8 before being delivered to the user. At the same time, in this process, the control feed gas (air) enters the adsorption tower B from the air main pipe 1 and the air inlet pipe 11 for adsorption, and the obtained nitrogen enters the nitrogen buffer tank 22 through the gas outlet pipe 21 and the nitrogen main pipe 2; in the role of the nitrogen vacuum pump 6 Next, the nitrogen in the nitrogen buffer tank 22 is sent to the nitrogen booster 7 to be compressed to the set pressure and then delivered to the user. After the adsorption tower A is saturated, the adsorption is stopped.

In steps 13 and 14, the pressure rise of adsorption tower A is equalized, and the pressure drop of adsorption tower B is equalized. The pressure equalization lower end control valve 411 and the pressure equalization upper end control valve 511 of the adsorption tower A and the pressure equalization lower end control valve 411 and the pressure equalization upper end control valve 511 of the adsorption tower B are all opened. The adsorption tower A and the adsorption tower B are connected through the pressure-equalizing lower end header 4 and the pressure-equalizing upper end header 5, so that the air pressure in the adsorption tower A gradually increases and the air pressure in the adsorption tower B gradually decreases, so that the air pressures of the two are basically the same.

In steps 15 and 16, the final pressure of adsorption tower A rises, and adsorption tower B waits. During this process, both the pressure equalization upper end control valve 511 of the adsorption tower A and the final lift master control valve 52 of the pressure equalization upper end header 5 are both opened. Since the air pressure in the adsorption tower A is still low, the nitrogen produced by the other adsorption towers 9 is sucked into the adsorption tower A, so that the air pressure in the adsorption tower A continues to rise.

In the present invention, in the process of equalizing pressure rise or equalizing pressure drop of the adsorption tower 9, the pressure equalizing upper header pipe 5 is used for pressure equalization; in the process of the final pressure rise of the adsorption tower 9, the final rise master control valve of the pressure equalizing upper header pipe 5 is used for pressure equalization. 52 is opened, and the pressure equalizing upper end header 5 is used for final pressure rise.

The bottom of the adsorption tower 9 is equipped with silica gel or alumina or 3A molecular sieve desiccant to adsorb water and carbon dioxide, and the main adsorbent is carbon molecular sieve. Due to the different diffusion rates of oxygen and nitrogen on the surface of carbon molecular sieve, a large amount of oxygen is adsorbed by carbon molecular sieve when passing through the adsorbent bed, and the amount of nitrogen adsorbed is relatively small. The outlet of adsorption tower 9.

After the air enters the adsorption tower 9 , oxygen and other gases are adsorbed by the nitrogen making adsorbent, and only nitrogen passes through the adsorption tower 9 . Since oxygen in the air occupies 21%, the oxygen is adsorbed by the nitrogen-producing adsorbent, which causes a large negative pressure to be formed in the adsorption tower 9, so that the air is sucked into the adsorption tower 9 under the action of negative pressure. At the same time, the nitrogen vacuum pump 6 draws the nitrogen gas to the nitrogen booster 7 to compress and remove nitrogen, which will also cause a negative pressure in the adsorption tower 9 to be formed. All of these make the pressure swing adsorption device for nitrogen production by negative pressure adsorption of the present invention can absorb air by itself, without sending air into the adsorption tower 9 through auxiliary equipment such as a blower, which simplifies the structure and reduces energy consumption at the same time.

When the high-purity nitrogen-producing device of the present invention is adsorbed by negative pressure adsorption, there is a negative pressure in the adsorption tower 9, which helps the nitrogen-producing adsorbent to absorb non-product gases, so that the adsorption effect is better, and the nitrogen produced is more efficient. higher purity. There is always one tower in adsorption and one tower in vacuum throughout the whole process, which increases the stability of the system.

In addition, the negative pressure adsorption high-purity nitrogen making device of the utility model can obtain and collect oxygen-enriched gas during desorption, so that two products can be produced at one time.

In this embodiment, a filter screen 12 is provided at the intake end of the air main pipe 1 . It can filter the particulate matter in the air and prevent it from entering the adsorption tower 9.

In this embodiment, the oxygen-enriched control valve 311 , the nitrogen control valve 211 , the pressure equalization lower control valve 411 , the pressure equalization upper control valve 511 , the final lift master control valve 52 and the air control valve 111 are all controlled by PLC or DCS system. The control of the device is made more intelligent, and the production efficiency is greatly improved.

In this embodiment, the number of the pressure equalizing lower end header pipes 4 is one. Each adsorption tower 9 is communicated with the pressure equalizing lower end header 4 . Opening the pressure-equalizing lower-end control valve 411 and the pressure-equalizing upper-end control valve 511 of any two of the adsorption towers 9 can make the two adsorption towers 9 communicate with each other, and both can be balanced through the pressure-equalizing lower-end header 4 and the pressure-equalizing upper-end header 5. pressure.

In this embodiment, a standby adsorption tower 9 is also included. The standby adsorption tower 9 is connected in parallel with the four adsorption towers 9 . The parallel connection here refers to: the standby adsorption tower 9 is provided with the oxygen-enriched branch pipe 31, the pressure-equalizing lower-end branch pipe 41, the pressure-equalizing upper-end branch pipe 51 and the gas outlet pipe 21 that are identical to the adsorption tower 9; the gas outlet pipe 21 is connected to the nitrogen main pipe 2 A nitrogen control valve 211 is provided; the oxygen-enriched branch pipe 31 is connected to the oxygen-enriched main pipe 3 and is provided with an oxygen-enriched control valve 311; The pressure upper end branch pipe 51 is connected to the pressure equalization upper end main pipe 5 and is provided with a pressure equalization upper end control valve 511 . When any adsorption tower 9 among adsorption tower A, adsorption tower B, adsorption tower C and adsorption tower D fails or needs to be replaced with molecular sieve, any adsorption tower 9 can be replaced with a spare adsorption tower 91 to avoid shutdown.

The above are only preferred embodiments of the present invention, and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims (7)

1. The utility model provides a high-purity nitrogen generator of negative pressure adsorption which characterized by: comprises a nitrogen header pipe (2), a pressure-equalizing lower end header pipe (4), an oxygen-enriched header pipe (3), an air header pipe (1), a pressure-equalizing upper end header pipe (5), a nitrogen vacuum pump (6), a nitrogen booster (7), an oxygen-enriched vacuum pump (8) and four adsorption towers (9); an adsorbent is arranged in the adsorption tower (9);

the bottom end of each adsorption tower (9) is communicated with the air main pipe (1) through an air inlet pipe (11), and the top end of each adsorption tower (9) is communicated with the nitrogen main pipe (2) through an air outlet pipe (21); each air inlet pipe (11) is provided with an air control valve (111), and each air outlet pipe (21) is provided with a nitrogen control valve (211);

a pressure equalizing upper end branch pipe (51) is communicated between each gas outlet pipe (21) and the corresponding adsorption tower (9) and the nitrogen control valve (211); the pressure equalizing upper end branch pipes (51) are communicated with the pressure equalizing upper end header pipe (5), and each pressure equalizing upper end branch pipe (51) is provided with a pressure equalizing upper end control valve (511); the pressure equalizing upper end header pipe (5) is communicated with the nitrogen header pipe (2); a final-rise master control valve (52) is arranged at one end, close to the nitrogen main pipe (2), of the pressure-equalizing upper-end main pipe (5);

an oxygen-enriched branch pipe (31) and a pressure-equalizing lower end branch pipe (41) are communicated between each air inlet pipe (11) and the corresponding adsorption tower (9) and the corresponding air control valve (111); the oxygen-enriched branch pipes (31) are communicated with the oxygen-enriched header pipe (3), and each oxygen-enriched branch pipe (31) is provided with an oxygen-enriched control valve (311); the pressure equalizing lower end branch pipes (41) are communicated with the pressure equalizing lower end header pipe (4), and each pressure equalizing lower end branch pipe (41) is provided with a pressure equalizing lower end control valve (411);

the nitrogen vacuum pump (6) and the nitrogen booster compressor (7) are connected in series with the nitrogen header pipe (2), so that nitrogen produced by the four adsorption towers (9) can be exhausted through the nitrogen vacuum pump (6) and the nitrogen booster compressor (7);

the oxygen-enriched vacuum pump (8) is connected to the oxygen-enriched header pipe (3) so that oxygen-enriched gas desorbed by the four adsorption towers (9) can be discharged through the oxygen-enriched vacuum pump (8).

2. The negative pressure adsorption high-purity nitrogen production device according to claim 1, which is characterized in that: the nitrogen header pipe (2) is also provided with a nitrogen buffer tank (22) so that nitrogen produced by the four adsorption towers (9) can pass through the nitrogen buffer tank (22) and then is discharged through a nitrogen vacuum pump (6) and a nitrogen booster (7); the oxygen-enriched main pipe (3) is also provided with an oxygen-enriched buffer tank (32) so that the oxygen-enriched gas desorbed by the four adsorption towers (9) can be discharged through the oxygen-enriched buffer tank (32) and then through the oxygen-enriched vacuum pump (8).

3. The negative pressure adsorption high-purity nitrogen production device according to claim 1, which is characterized in that: and a filter screen (12) is arranged at the air inlet end of the air main pipe (1).

4. The negative pressure adsorption high-purity nitrogen production device according to claim 1, which is characterized in that: the bottom layer of the adsorption tower (9) is filled with alumina or silica gel or a 3A molecular sieve; the upper layer of the adsorption tower (9) is provided with a carbon molecular sieve.

5. The negative pressure adsorption high-purity nitrogen production device according to claim 1, which is characterized in that: the oxygen enrichment control valve (311), the nitrogen control valve (211), the pressure equalizing lower end control valve (411), the pressure equalizing upper end control valve (511), the final rise master control valve (52) and the air control valve (111) are controlled by a PLC or a DCS.

6. The negative pressure adsorption high-purity nitrogen production device according to claim 1, which is characterized in that: the number of the pressure equalizing lower header pipes (4) is 1; each adsorption tower (9) is communicated with the pressure-equalizing lower-end header pipe (4).

7. The negative pressure adsorption high-purity nitrogen production device according to claim 6, which is characterized in that: further comprises a standby adsorption tower (91); the standby adsorption tower (91) is connected with the four adsorption towers (9) in parallel.

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