JPH07110328B2 - Pressure swing adsorption type high-purity nitrogen production method and apparatus - Google Patents

Description

The present invention relates to a pressure swing adsorption type high-purity nitrogen production method and apparatus for separating and recovering high-purity nitrogen (N ₂ ) from air (hereinafter simply referred to as “N”). _2- PSA method and apparatus).

[Conventional technology]

Conventionally, for example, as shown in FIG. 3, an N ₂ -PSA device configured in a three-column type is known. At the inlets of the three adsorption towers 11, 12, and 13 that use synthetic zeolite as an adsorbent, the downstream end of the raw material air supply pipe line 2 is connected via valves 21, 22, and 23, and also to the cleaning gas supply pipe line 3. The downstream ends are connected via valves 31, 32 and 33, respectively. On the other hand, at the outlets of the adsorption towers 11, 12, and 13, the upstream ends of the exhaust gas discharge conduits 4 are connected via valves 41, 42, 43, and the upstream ends of the desorption gas recovery conduit 5 are connected to valves 51, 52, 53. Are respectively connected via. The upstream end of the raw material air supply conduit 2 and the downstream end of the exhaust gas discharge conduit 4 are connected to the pretreatment unit 7, and the upstream end of the cleaning gas supply conduit 3 and the desorption gas recovery conduit 5 are connected. Is connected to the product N ₂ holder 6. In addition, the three adsorption towers 11, 12, 13 are connecting pipes 1
4,15,16 are in communication with one another via valves 141,151,161.

The pretreatment unit 7 is composed of two pretreatment towers 71 and 72 and an air holder 73, and the two pretreatment towers 71 and 72 are arranged in parallel between the raw air compressor 10 and the air holder 73. It is arranged. The raw material air compressor 10 and the pretreatment towers 71 and 72 are connected via valves 701 and 702, and the pretreatment towers 71 and 72 and the air holder are also provided.
73 is connected through valves 731 and 732, respectively. Further, the pretreatment towers 71 and 72 and the exhaust gas discharge pipeline 4 are provided with valves 741 and 742.
Connected through.

In the pretreatment unit 7, the raw material air is pressurized by the raw material air compressor 10, and the raw material air is passed through the pretreatment tower 71 to adsorb moisture (H ₂ O) and carbon dioxide gas (CO ₂ ). Is
The remaining raw material air which is a mixed gas of mainly oxygen (O ₂ ) and nitrogen (N ₂ ) is stored in the air holder 73. The air holder 73 is connected to the upstream end of the raw material air supply pipe line 2, and the raw material air is selectively supplied to the three adsorption towers 11, 12, 13 by opening / closing the three valves 21, 22, 23. It

In the three adsorption towers 11, 12, and 13, as shown in FIG.
One cycle consisting of an adsorption step, a recovery step, a rest step, a washing step, and a desorption step has three adsorption towers 11, 12,
It is operated continuously by shifting 1/3 cycle by 13 and each pipeline 2,
The valves that connect the 3,4,5 and the adsorption towers 11,12,13 to each other are automatically opened and closed so that the desorbed and recovered high-purity N ₂ gas is continuously stored in the product N ₂ holder 6. I have to.

The above one cycle will be described with reference to FIGS. 3 and 4 centering on the first adsorption tower 11. First, the raw material air is supplied from the air holder 73 through the valves 20 and 21 to the first adsorption tower 11 which is in the depressurized state in the previous step, and the pressure inside the first adsorption tower 11 is increased by the raw material air. Then, the N ₂ component in the raw material air is preferentially adsorbed by the adsorbent in the first adsorption tower 11 (pressurization, adsorption step).

Next, the valve 41 is opened and the third adsorption tower 13 is opened.
The cleaning exhaust gas from the cleaning exhaust gas is supplied to the first adsorption tower 11 through the communication pipe line 16, whereby the N ₂ component in the cleaning exhaust gas is adsorbed and recovered by the adsorbent in the first adsorption tower 11 and consists of the remaining O ₂ rich gas. The cleaning exhaust gas is guided to the pretreatment tower 72 through the exhaust gas discharge conduit 4 (collection step).

H ₂ O adsorbed on the pretreatment units 71 and 72 by this cleaning exhaust gas
And CO ₂ are desorbed, and the H ₂ O and CO ₂ are discharged to the atmosphere via valves 751 and 752.

This completes the pressurization, adsorption process and recovery process in the first adsorption tower 11. During these periods, the desorption process is performed in the second adsorption tower 12, and the resting process and the cleaning process are performed in the third adsorption tower 13.

Next, the first adsorption tower 11 pauses until the pressurization and adsorption steps in the second adsorption tower 12 are completed, and then the product N ₂ is fed into the first adsorption tower 11.
High-purity N ₂ gas, which is the product N ₂ , is introduced from the holder 6 through the cleaning gas supply line 3 as the cleaning gas by opening the valve 31. Depending on the N ₂ component in this cleaning gas,
O ₂ partially adsorbed by the adsorbent in the adsorption tower 11 is replaced and desorbed, and the cleaning exhaust gas is sent to the second adsorption tower 12 through the communication pipe line 14. The N ₂ concentration of the cleaning exhaust gas passing through this communication line 14 is detected, and when this N ₂ concentration reaches a predetermined value, the valve 141 is closed. As a result, the first adsorption tower 11 is filled with high-purity N ₂ component gas (cleaning step). During this time, the desorption process is performed in the third adsorption tower 13.

Thereafter, by opening the valve 51 and operating the vacuum pump 54 provided in the desorption gas recovery pipe line 5, the inside of the first adsorption tower 11 is decompressed and the N ₂ component is desorbed from the adsorbent,
The desorbed N ₂ component is collected in the product N ₂ holder 6. During this period, the resting step and the washing step are performed in the second adsorption tower 12, and the pressurization, the adsorption step and the recovery step are performed in the third adsorption tower 13, respectively.

Then, in the first adsorption tower 11, the above steps from the pressure increasing step and the adsorption step are repeated again in sequence, and the corresponding steps in the other adsorption towers 12 and 13 are also repeated. As a result, high-purity N ₂ component gas is continuously stored in the product N ₂ holder 6 as product N ₂ .

In the recovery process of the adsorption towers 11, 12, and 13 among the above-mentioned steps, the cleaning exhaust gas is sent as exhaust gas to one of the pretreatment towers 71, 72 through the exhaust gas discharge pipe 4, and the exhaust gas is regenerated in the pretreatment tower. Is done. Of the two pretreatment towers 71, 72, one is an adsorption step for adsorbing H ₂ O and CO ₂ in the feed air, and the other is a regeneration step for desorbing and regenerating the H ₂ O and CO _2. Done.

For example, when the first pretreatment tower 71 is an adsorption process, the valve 701 and the valve 7
31 is set to an open state, valves 741 and 751 are set to a closed state, and in the second pretreatment tower 72, a valve 702 and a valve 732 are closed,
742 and valve 752 are set to the open state, respectively, and the regeneration process is performed. These valves consist of automatic on-off valves,
The states are automatically switched to the opposite states at predetermined time intervals, so that the adsorbent in the pretreatment tower in the adsorption process is switched to the regeneration process before the breakthrough condition occurs.

[Problems to be Solved by the Invention]

In the above-mentioned conventional N ₂ -PSA method and apparatus, when switching the two pretreatment towers 71, 72 of the pretreatment section 7, for example, when the first pretreatment tower 71 is in the adsorption step, the valve 741 is sandwiched between the first pretreatment tower 71 and the first pretreatment tower 71. Relatively high pressure raw material air pressurized by the raw material air compressor 10 is provided in the pretreatment tower 71 side, and relatively low pressure cleaning exhaust gas is provided in the adsorption towers 11, 12, 13 side pipeline 4. Since the valves 741 and 751 are actuated because they exist respectively,
There is a problem that the raw material air flows back through the exhaust gas discharge pipe line 4 through the valve 741 due to the pressure difference and enters the adsorption towers 11, 12, 13 in a short time when the pressure is released through the 751.

In order to prevent this, it is conceivable that the valves 741 and 742, which are the connecting portions with the exhaust gas discharge pipeline 4, are configured as check valves. However, even in this case, since the pressure difference between the raw material air and the cleaning exhaust gas is relatively large, the raw material air instantaneously leaks into the exhaust gas discharge pipe line 4 at the time of switching between the regeneration process and the adsorption process, and the adsorption towers 11, 12 There is a risk of entering 13, The leaked air feed reduces the purity of the product N _2, tends to product purity N ₂ is increased higher to be obtained the effect of the feed air for the decreased purity, the purity improve product N ₂ It causes the inhibition.

The present invention has been made to solve such a conventional problem, and improves the purity of the product N ₂ by reliably preventing the raw material air from flowing back into the adsorption tower through the exhaust gas discharge pipeline. It is an object of the present invention to provide an N ₂ -PSA method and device capable of performing the same.

[Means for Solving the Problems]

In order to achieve the above object, in claim 1 of the present invention, the raw material air is pretreated by adsorbing and removing water and the like in the pretreatment section, and the pretreated raw material air is fed to the adsorption tower through the raw material air supply pipe line. A pressure swing in which the nitrogen component in the raw material air is adsorbed and recovered in this adsorption tower, and the exhaust gas from this adsorption tower is passed through the pretreatment section through the exhaust gas discharge pipe, and the desorption regeneration of the pretreatment section is performed by this exhaust gas. In the adsorption-type high-purity nitrogen production method, the pretreatment section is composed of a plurality of pretreatment towers, part of the plurality of pretreatment towers is adsorbed and removed, and the other part is desorbed and regenerated. These steps are switched by the opening / closing operation of the valve, and in accordance with this switching, the raw material air that flows back into the exhaust gas discharge line via the valve is provided in the exhaust gas discharge line. It was configured to store by.

Further, in claim 2, in addition to the structure of claim 1, a recovery holder is provided on the side of the adsorption tower of the exhaust gas discharge pipe, and the recovery holder has a relatively low N ₂ concentration in the exhaust gas discharged from the adsorption tower. High exhaust gas was stored, and after the adsorption tower completed the desorption process, this exhaust gas was put into this adsorption tower before the pressurization and adsorption processes to adsorb the N ₂ component.

Further, as an apparatus for carrying out the above-mentioned manufacturing method, in claim 3, a plurality of pretreatment towers for adsorbing and removing water and the like from the raw material air to pretreat, and N ₂ from the raw material air pretreated by the pretreatment tower. A pretreatment tower and an adsorption tower having an adsorption tower for adsorbing components, the exhaust gas from the adsorption tower being connected to each other by an exhaust gas discharge pipeline so that the exhaust gas can be sent to the pretreatment tower, and the pretreatment tower Raw material air from the above is connected to each other by a raw material air supply pipeline so as to be able to supply to the adsorption tower, these two pipelines and the pretreatment tower are switchably connected to each other by a valve, and the exhaust gas discharge pipeline is pretreated. A trapping holder for accumulating the raw material air flowing into the exhaust gas discharge pipe when the tower and the two pipes are switched is provided.

In the fourth aspect, in addition to the configuration of the third aspect, the exhaust gas discharge pipeline is provided with a recovery holder on the adsorption tower side and a bypass pipeline that bypasses the recovery holder.

In claim 5, the recovery holder in claim 4 is filled with an adsorbent.

[Action]

According to the configurations of claims 1 and 3, even if the raw material air leaks from the valve when the pretreatment tower is switched, the raw material air is stored in the trapping holder, so that the raw material air is introduced into the adsorption tower through the exhaust gas discharge pipeline. There is no inflow.

Further, according to the configurations of claims 2 and 4, the exhaust gas supplied to the pretreatment tower through the exhaust gas discharge pipeline is normally passed through the bypass pipeline and discharged to the exhaust gas discharge pipeline near the end of the recovery process. The exhaust gas with a relatively high N ₂ concentration is stored in the recovery holder, and the exhaust gas with a relatively high N ₂ concentration is put into the adsorption tower before pressurization and before the adsorption process after the desorption process is completed and the N ₂ component of the exhaust gas is removed. By adsorbing on the adsorbent, the recovery rate of the N ₂ component can be improved.

Further adsorbing the example N ₂ components in the exhaust gas to the adsorbent constituent to the collecting holder according to claim 5, efficiency recovery of N ₂ components by putting the N ₂ component is this adsorbed by the adsorption tower Can be improved well.

[Embodiment] FIG. 1 shows N ₂ -PSA for carrying out the manufacturing method of the present invention.
The device is shown. This device is a conventional N ₂ − shown in FIG.
Adsorption towers 11,12,13 in PSA equipment, these adsorption towers 11,1
The exhaust gas exhaust pipe 4 has a trapping holder 8 in the exhaust gas exhaust pipe 4, which has basically the same structure as the pipes 2, 3, 4, 5 connected to the pipes 2, 13 and the pretreatment unit 7. The recovery holder 9 filled with synthetic zeolite as the adsorbent 91 and the bypass conduit 4a are additionally provided.

That is, the exhaust gas discharge line 4 has its pretreatment towers 71, 72
The holding holder 8 is provided on the side, the collection holders 9 are provided on the adsorption towers 11, 12, and 13, respectively, and the bypass conduit 4a that bypasses the collection holder 9 is provided. The bypass conduit 4a is connected between the upstream side of the inlet valve 44 and the downstream side of the outlet valve 45 of the recovery holder 9, and an opening / closing valve 46 is provided in the bypass conduit 4a. Further, the valves 761 and 762 that connect the exhaust gas discharge conduit 4 and the pretreatment towers 71 and 72 are configured as check valves.

As shown in Fig. 2, the operating method of the N ₂ -PSA device with the above-mentioned configuration is basically the same as the conventional operating method in that one cycle is composed of pressurization, adsorption step, recovery step, rest step, washing step and desorption step. However, the delivery of gas between the adsorption towers 11, 12, and 13 and the pretreatment section 7 is different from the conventional method in the pressurization / adsorption step and the recovery step. This N ₂ -PSA
The operation method of the apparatus will be described from the start of the recovery step of the first adsorption tower 11 based on FIGS. 1 and 2 centering on the exhaust gas discharge pipe 4. It is assumed that at the above-mentioned time point, in the pretreatment section 7, the first pretreatment tower 71 is in the adsorption step and the second pretreatment tower 72 is in the regeneration step.

The recovery process of the first adsorption tower 11 is the third adsorption tower in the cleaning process.
Cleaning exhaust gas from 13 passes through connecting line 16 to the first adsorption tower 11
The introduced N ₂ component in the cleaning exhaust gas is adsorbed and collected by the adsorbent in the first adsorption tower 11, and the remaining cleaning exhaust gas is sent to the pretreatment tower 72 through the exhaust gas discharge pipe 4.

At this time, in the exhaust gas discharge conduit 4, the valve 41 and the valve 46 are set to the open state, and the valve 42, the valve 43, the valve 44 and the valve 45 are set to the closed state. Therefore, the cleaning exhaust gas is sent to the pretreatment tower 72 through the bypass line 4a.

The cleaning exhaust gas according to the progress of the recovery process will not take place recovery of N ₂ components therein, the N ₂ concentration in the N ₂ concentration approaching the N ₂ concentration in the product N ₂ is gradually cleaning gas It becomes a relatively high gas. Therefore, between the end of the recovery process (for example, when 40 seconds elapses in the recovery process) and the end of the recovery process, the valve 46 of the bypass conduit 4a is closed and the valve 44 and the valve 45 are connected. Is opened, whereby the cleaning exhaust gas with a relatively high N ₂ concentration is introduced into the recovery holder 9, and the adsorbent 91 in the recovery holder 9 adsorbs the N ₂ component in the cleaning exhaust gas.

After completion of the recovery step, while keeping the valve 46 in the closed state and the valve 44 in the open state, the valve 41 and the valve 45 are closed for a predetermined time (for example, 1 to 2 seconds), and the valve 42 is opened. Make it open. As a result, the second adsorption tower 12 whose internal pressure has been reduced after the desorption process is completed is brought into communication with the recovery holder 9. As a result, the inside of the recovery holder 9 is decompressed and the N ₂ component is desorbed from the adsorbent 91, this desorbed gas enters the second adsorption tower 12, and this second adsorption tower 12 is separated by this desorbed gas. Is boosted only and its N ₂ component is the second
Adsorbed on the adsorbent of the adsorption tower 12.

As a result, the N ₂ component can be effectively recovered from the cleaning exhaust gas that was conventionally discarded into the atmosphere through the pretreatment unit 7, so the recovery rate of the N ₂ component from the raw material air taken into the device is improved. be able to.

After that, by closing the valves 42 and 44, the second
Raw material air is supplied to the adsorption tower through the raw material air supply pipe line 2 in the same manner as in the conventional method, and the inside of the second adsorption tower 12 is pressurized by the raw material air, and the N ₂ component in the raw material air is adsorbed. .

Then, the valve 42 and the valve 46 are opened at the time when the pressure raising and adsorption steps of the second adsorption tower 12 are completed and the recovery step is started. As a result, the cleaning exhaust gas from the second adsorption tower 12 is sent to the second pretreatment tower 72 through the bypass pipe line 4a as in the recovery step of the first adsorption tower 11. At the end of the recovery process of the second adsorption tower 12, the valve 46 is closed and the valves 44 and 45 are closed.
The cleaning exhaust gas having a relatively high N ₂ concentration is passed through the recovery holder 9 and the N ₂ component is adsorbed by the adsorbent 91. Then, after the recovery step of the second adsorption tower 12,
By connecting the recovery holder 9 and the third adsorption tower 13 that has completed the desorption process, the recovery holder 9
The N ₂ component is desorbed from the adsorbent 91 inside and the desorbed gas is put into the third adsorption tower 13.

Thereafter, similarly, the cleaning exhaust gas discharged toward the end of the recovery process of the third adsorption tower 13 is passed through the recovery holder 9, and the N ₂ component in the cleaning exhaust gas is adsorbed and recovered to make the first adsorption of the N ₂ component. It is put into the first adsorption tower 11 before the pressure rising and adsorption steps of the tower 11 are started.

On the other hand, the first pretreatment tower in the adsorption step in the pretreatment section 7
Before the adsorbent in 71 enters the breakthrough state, the valves 731 and 701 are operated in the closed state and the valve 751 is operated in the open state on the first pretreatment section 71 side, and on the second pretreatment tower 72 side. The valves 732 and 702 are operated in the open state and the valve 752 in the closed state, whereby the first pretreatment tower 71 is changed from the adsorption step to the regeneration step and the second pretreatment tower.
72 is switched from the regeneration process to the adsorption process.

At the time of this switching, the raw material air under pressure momentarily leaks through the valves 761 and 762, and even if the leaked raw material air (hereinafter referred to as leak raw material air) flows backward in the exhaust gas discharge pipe line 4 due to the pressure difference, Since the air is stored and captured in the capture holder 8, the leaked raw material air is absorbed in the adsorption tower.
It does not flow into 11,12,13. This makes it possible to prevent a decrease in purity of the product N _2, product N ₂ than the conventional N ₂
The purity can be improved.

In the above embodiment, the case where the adsorbent 91 is filled in the recovery holder 9 is shown, but the present invention is not limited to this.
For example, the adsorbent 91 may not be filled. In this case, the cleaning exhaust gas having a relatively high N ₂ concentration discharged near the end of the recovery process is closed by the valve 45 and the recovery holder 9 is used.
It is only necessary to store the gas inside and to introduce the collected cleaning exhaust gas into the adsorption tower after the desorption process.

Further, in the above-described embodiment, the case where the trapping holder 8 and the recovery holder 9 are arranged side by side in the exhaust gas discharge conduit 4 is shown, but the present invention is not limited to this, and for example, only the trapping holder 8 is provided in the exhaust gas discharge conduit. it may constitute the N _2-PSA apparatus Te.
Even in this case, it is possible to reliably prevent the backflow of the raw material air to the adsorption towers 11, 12, 13 due to the switching of the steps of the pretreatment towers 71, 72, thereby improving the purity of the product N _2. be able to.

〔Concrete example〕

By the method of the above-mentioned embodiment using the N ₂ -PSA apparatus shown in FIG. 1 and the conventional method using the N ₂ -PSA apparatus shown in FIG. 3, the raw material air amount is 60 Nm ³ / h, the pressure is 4.0 Kg. The raw material air of / cm ² was supplied to the pretreatment tower, the adsorption step and the regeneration step of the pretreatment tower were switched every 3 minutes, and the operation was performed so as to take out ₂₀ Nm ³ / h of product N ₂ .

As a result, the purity of the product N ₂ is 9 when the conventional method is used.
In the case of the present invention, N ₂
The purity could be improved to 99.999%.

〔The invention's effect〕

According to the N ₂ -PSA method and apparatus of claims 1 and 3 of the present invention, even if the raw material air leaks from the valve when the pretreatment tower is switched, it is stored in the trapping holder, so the raw material air is exhaust gas. There is no backflow into the adsorption tower through the discharge line. This can improve the purity of the product N ₂ .

Further, according to the method and the apparatus of claims 2 and 4, the exhaust gas is discharged to the exhaust gas discharge pipeline at the end of the recovery step.
Exhaust gas with a relatively high N ₂ concentration is stored in a recovery holder, and this exhaust gas with a relatively high N ₂ concentration is pressurized after the desorption process,
In addition to the effect of improving the purity of the product N ₂ in the above-mentioned claim 1 and claim 3, by adsorbing the N ₂ component of the exhaust gas into the adsorbent by putting it in the adsorption tower before the start of the adsorption step,
It is also possible to improve the recovery rate of the N ₂ component.

Further adsorbing the example N ₂ components in the exhaust gas to the adsorbent constituent to the collecting holder according to claim 5, efficiency recovery of N ₂ components by putting the N ₂ component is this adsorbed by the adsorption tower Can be improved well.

[Brief description of drawings]

FIG. 1 is an explanatory view of an embodiment of an N ₂ -PSA device according to the present invention, FIG. 2 is a process explanatory view of a method for producing high purity N ₂ using the device of FIG. 1, and FIG. Explanatory drawing of N ₂ -PSA device,
FIG. 4 is a process explanatory diagram of a method for producing high-purity N ₂ using a conventional N ₂ -PSA apparatus. 2 ... Raw material air supply line, 3 ... Cleaning gas supply line,
4 ... Exhaust gas discharge pipeline, 5 ... Desorption gas recovery pipeline, 6 ...
… Product N ₂ holder, 7 …… Pretreatment section, 8 …… Capture holder, 9 …… Recovery holder, 11,12,13 …… Adsorption tower, 7
1,72 …… Pretreatment tower, 761,762 …… Valve connecting the pretreatment tower and the exhaust gas discharge line.

Claims (5)

[Claims] 1. A raw material air is pretreated by adsorbing and removing water and the like in a pretreatment section, and the pretreated raw material air is supplied to an adsorption tower through a raw material air supply pipe line, and the raw material air is fed into the adsorption tower. The nitrogen component of is adsorbed and recovered, and the exhaust gas from this adsorption tower is passed through the pretreatment section through an exhaust gas discharge pipe line,
In the pressure swing adsorption type high-purity nitrogen production method of performing desorption regeneration of the pretreatment section by this exhaust gas, the pretreatment section is composed of a plurality of pretreatment towers, and an adsorption removal step is performed in a part of the plurality of pretreatment towers. The desorption / regeneration process is performed in other parts, and these processes are switched to each other by the opening / closing operation of the valve. Along with this switching, the raw material air that flows backward into the exhaust gas exhaust pipe through the valve is exhausted from the exhaust gas exhaust pipe. A pressure swing adsorption type high-purity nitrogen production method characterized in that it is stored by a trapping holder provided in a passage. 2. A recovery holder is provided on the adsorption tower side of the exhaust gas discharge pipe, and the exhaust gas discharged from the adsorption tower has a relatively high concentration of N ₂ and is adsorbed on the recovery holder. The pressure swing adsorption type high-purity nitrogen production method according to claim 1, wherein the column is placed in the adsorption column after the desorption step and before the pressurization and adsorption steps to adsorb the N ₂ component. 3. A plurality of pretreatment towers for pretreatment by adsorbing and removing water and the like from the raw material air, and an adsorption tower for adsorbing N ₂ component from the raw material air pretreated by the pretreatment tower,
The pretreatment tower and the adsorption tower are connected to each other by an exhaust gas discharge pipeline so that the exhaust gas from this adsorption tower can be sent to the pretreatment tower, and the raw material air from the pretreatment tower can be supplied to the adsorption tower. Connected to each other by a raw air supply line,
These two pipes and the pretreatment tower are connected by a valve so that they can be switched to each other, and the raw material flowing into the exhaust gas discharge pipeline when the pretreatment tower and the two pipelines are switched to each other. A pressure swing adsorption type high-purity nitrogen manufacturing device, characterized in that a trapping holder for accumulating air is provided. 4. The pressure swing adsorption system according to claim 3, wherein the exhaust gas discharge pipe line is provided with a recovery holder on the adsorption tower side and a bypass pipe line that bypasses the recovery holder. High-purity nitrogen production equipment. 5. The pressure swing adsorption type high-purity nitrogen producing apparatus according to claim 4, wherein the recovery holder is filled with an adsorbent.