JPH0560460A - Device for manufacturing high purity nitrogen and oxygen gas - Google Patents

Abstract

PURPOSE:To permit the manufacture of high purity nitrogen gas without employing any expansion turbine or refining device by a method wherein a liquid nitrogen reserving tank is employed instead of the expansion turbine while liquid nitrogen and liquid oxygen, whose supplying amount can be controlled delicately, are employed as cold heat. CONSTITUTION:The title device is provided with a nitrogen fractionating tower 12, liquefying a part of compressed air to reserve it in the tower and retaining only nitrogen as gas, and an oxygen fractionating tower 21, separating nitrogen from oxygen in liquid air utilizing the difference between boiling points thereof, while the reserved low-temperature liquefied gas of at least one of a liquid nitrogen reserving means 14 and a liquid oxygen reserving means 23 is introduced into the fractionating tower of same gas as the low-temperature liquefied gas through low-temperature liquefied gas introducing passages 14a, 23a as a cold heat source. According to this method, delicate following with respect to the fluctuation of a load can be effected whereby nitrogen gas and oxygen gas, having stabilized and very high purity, can be manufactured.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for producing high purity nitrogen and oxygen gas.

[0002]

2. Description of the Related Art An extremely large amount of nitrogen gas is used in the electronic industry, but there is a strict demand for the purity of nitrogen gas from the viewpoint of maintaining and improving the accuracy of parts. That is, nitrogen gas generally uses air as a raw material, compresses it with a compressor, puts it in an adsorption column to remove carbon dioxide gas and water, and further cools it by exchanging heat with a refrigerant through a heat exchanger. It is manufactured through a process in which a product nitrogen gas is manufactured by cryogenic liquefaction separation in a rectification tower and heated to near room temperature through the heat exchanger. However, in the product nitrogen gas produced in this way, oxygen is mixed as an impurity, so that it is often inconvenient to use it as it is. As a method of removing impure oxygen, a method of adding a trace amount of hydrogen to nitrogen gas using Pt catalyst to react with impure oxygen in a temperature atmosphere of about 200 ° C. and removing as water, and a Ni catalyst are used.
There is a method of removing impure oxygen in nitrogen gas by bringing it into contact with a Ni catalyst in a temperature atmosphere of about 200 ° C. to cause a reaction of Ni + 1 / 2O ₂ → NiO. However, in any of these methods, the temperature of nitrogen gas must be raised to bring it into contact with the catalyst, and therefore the apparatus cannot be incorporated in a nitrogen gas production apparatus which is an ultralow temperature system. Therefore, the refining device must be installed separately from the nitrogen gas production device, which has the disadvantage of increasing the overall size. Moreover, in the above method, high precision is required for adjusting the amount of hydrogen added, and if hydrogen is not added in an amount just enough to react with the amount of impure oxygen, oxygen will remain or the added hydrogen will remain. Therefore, there is a problem that it requires skill to operate because it becomes impure. Furthermore, in the above method, the NiO generated by the reaction with impure oxygen is regenerated (NiO + H ₂ →
Ni + H ₂ O) is required, and a H ₂ gas facility for regeneration is required, which causes an increase in refining cost. Therefore, these improvements were strongly desired.

Further, the conventional nitrogen gas producing apparatus uses an expansion turbine for cooling the refrigerant of a heat exchanger for cooling the compressed air compressed by the compressor, and a liquid which collects the expansion turbine in the rectification column. It is driven by the pressure of the gas evaporated from the air (nitrogen having a low boiling point is taken out as a gas by the cryogenic liquefaction separation, and the rest is stored as oxygen-rich liquid air). However, the expansion turbine has an extremely high rotation speed (tens of thousands of times / minute), and it is difficult to follow the load fluctuation, and a specially trained operator is required. Also,
Since this machine rotates at high speed, it requires high precision in terms of mechanical structure, is expensive, and has a complicated mechanism, which requires specially trained personnel. That is, since the expansion turbine has a high-speed rotating part, the above-mentioned various problems occur, and there is a strong demand for the removal of the expansion turbine having such a high-speed rotating part.

In order to meet such a demand, the inventor of the present invention has developed a nitrogen gas production apparatus which removes the expansion turbine and instead supplies liquid nitrogen from the outside into the rectification column as refrigeration, and has already applied for a patent. (Japanese Patent Application No. 58-38050)
is doing. Since this apparatus can produce extremely high-purity nitrogen gas, the refining apparatus as in the past is completely unnecessary. Further, since the expansion turbine is removed, no harmful effect based on it is caused. Therefore, it is most suitable for the electronics industry. However, in the electronics industry, oxygen gas is used in addition to nitrogen gas, and it has been desired to provide a device that can produce not only nitrogen gas but also oxygen gas with one device.

[0005]

DISCLOSURE OF THE INVENTION The present invention is a high-purity nitrogen and oxygen gas production apparatus capable of producing high-purity nitrogen gas without using an expansion turbine or a refining apparatus and at the same time producing high-purity oxygen gas. The purpose is to provide.

[0006]

In order to achieve the above object, the present invention provides an air compression means for compressing air taken in from the outside, and carbon dioxide in compressed air compressed by the air compression means. Removal means for removing gas and water, heat exchange means for cooling the compressed air passed through the removal means to an ultra low temperature, liquid nitrogen storage means for storing liquid nitrogen, and compression cooled to an ultra low temperature by the heat exchange means. Nitrogen rectification column that liquefies a part of air and retains only nitrogen as a gas inside, and introduces the liquid nitrogen in the liquid nitrogen storage means into the nitrogen rectification column as a cold source for liquefying compressed air. A liquid nitrogen introduction passage and a nitrogen gas extraction passage for taking out both the liquid nitrogen vaporized after finishing the action as a cold source and the vaporized nitrogen held in the nitrogen rectification tower as product nitrogen gas from the nitrogen rectification tower. When, An oxygen rectification column that targets body air by utilizing the difference in the boiling points of nitrogen and oxygen, and a liquid air supply path that supplies the retained liquid air in the nitrogen rectification column into the oxygen rectification column A liquid oxygen storage means for storing liquid oxygen, a liquid oxygen introduction path for guiding liquid oxygen in the liquid oxygen storage means to the oxygen rectification column as a cold source, and liquid air as a raw material for the boiling points of oxygen and nitrogen. High-purity nitrogen and oxygen provided with an oxygen gas take-out path for taking out from the oxygen rectification column both oxygen gas separated by utilizing the difference and liquid oxygen vaporized after finishing the action as a cold source as product oxygen gas The first aspect of the present invention is a gas production apparatus, an air compression means for compressing air taken in from the outside, a removal means for removing carbon dioxide gas and water in the compressed air compressed by the air compression means, and Pressure through removal means A heat exchange means for cooling the air to an ultra low temperature, a liquid nitrogen storage means for storing liquid nitrogen, and a part of the compressed air cooled to an ultra low temperature by the heat exchange means is liquefied to retain only nitrogen as a gas inside Nitrogen rectification column, liquid nitrogen in the liquid nitrogen storage means to introduce liquid nitrogen into the nitrogen rectification column as a cold source for compressed air liquefaction, and liquid vaporized after finishing the action as a cold source Both nitrogen and vaporized nitrogen retained in the nitrogen rectification tower are taken out from the nitrogen rectification tower as product nitrogen gas, and a nitrogen gas extraction path for liquid air to vaporize the nitrogen content and enrich it with oxygen content. Oxygen condensing column to be in a state of being in a state, a liquid air supply path for supplying the retained liquid air in the nitrogen rectifying column into the oxygen condensing column, and oxygen for separating the two by utilizing the difference in boiling points of oxygen and nitrogen. Rectification tower and above oxygen A supply path for supplying liquid oxygen-rich liquid in the condensing tower into the oxygen rectification tower, liquid oxygen storage means for storing liquid oxygen, and liquid oxygen in the liquid oxygen storage means as a cold source. Liquid oxygen introduction path leading to the oxygen rectification column, oxygen gas separated from liquid air rich in oxygen as a raw material by utilizing the difference in boiling points of oxygen and nitrogen, and liquid vaporized after the action as a cold source The second gist of the present invention is a high-purity nitrogen and oxygen gas production apparatus provided with an oxygen gas take-out path for taking out both of oxygen as product oxygen gas from the oxygen rectification column.

Next, the present invention will be described in detail based on examples.

[0008]

FIG. 1 shows an embodiment of the present invention. In the figure, 1 is a first air compressor, 2 is a waste heat recovery device, 3 is an intercooler, 4 is a second air compressor, 5 is an aftercooler, and 6 is a set of two air cooling tubes. One (6a) is a closed type, and the other (6b) is an upper open type. Numeral 7 is a set of two adsorption cylinders, which are filled with a molecular sieve, and alternate between H ₂ O and CO ₂ in the air compressed by the first and second air compressors 1 and 4. It works by adsorbing and removing. Reference numeral 8 is a first heat exchanger, and H ₂ O and C are added to the heat exchanger 8 by the adsorption cylinder 7.
The compressed air from which O ₂ has been adsorbed and removed is sent through the compressed air supply pipe 9 and cooled to an ultra-low temperature by the heat exchange action. Reference numeral 10 is a second heat exchanger, and the branch pipe 11 branched from the compressed air supply pipe 9 feeds the compressed air from which H ₂ O and CO ₂ have been adsorbed and removed. The compressed air sent to the second heat exchanger 10 is also cooled to an ultra-low temperature by the heat exchange action, and then merged with the ultra-low temperature compressed air cooled by the first heat exchanger 8. Reference numeral 12 denotes a tray type nitrogen rectification column, which further cools the compressed air that is cooled to an ultralow temperature by the first and second heat exchangers 8 and 10 and is sent through the pipe 9, and liquefies a part of the compressed air. Air 13 is stored at the bottom and only nitrogen is taken out in a gaseous state. A liquid nitrogen reservoir 12a is provided in the upper portion of the rectification column 12, and liquid nitrogen is fed from the liquid nitrogen storage tank 14 through the introduction pipe 14a. The introduced liquid nitrogen overflows from the liquid nitrogen reservoir 12a and flows downward in the rectification column 12, and comes into countercurrent contact with the compressed air rising from the bottom of the rectification column 12 to cool it. The part is designed to be liquefied. That is,
In this process, the high boiling point component (oxygen content) in the compressed air is liquefied and collected at the bottom of the rectification column 12, and the low boiling point component nitrogen gas is collected at the top of the rectification column 12. Reference numeral 19 is an extraction pipe for taking out the nitrogen gas thus accumulated in the upper portion of the rectification column 12 as product nitrogen gas, which guides the ultra-low temperature nitrogen gas into the first heat exchanger 8 and is compressed therein. It exchanges heat with air to bring it to room temperature and sends it into the main pipe 20. In this case, at the top of the rectification column 12, together with nitrogen gas, He (−269 ° C.) and H ₂ (−253 ° C.) having a low boiling point are used.
(° C) tends to accumulate, so the take-out pipe 19 is used in the rectification tower 12
The opening is considerably lower than the uppermost part of the above, and only pure nitrogen gas in which He and H ₂ are not mixed is taken out. Reference numeral 15 is a tray type oxygen condensing tower, in which a condenser 16 is disposed. A part of the nitrogen gas accumulated in the upper portion of the rectification column 12 is fed into the condenser 16 through the pipe 12b and liquefied, and the introduction passage pipe 14a is passed through the pipe 12c.
It joins the liquid nitrogen inside. The inside of the oxygen condensing tower 15 is in a reduced pressure state as compared with the inside of the rectification tower 12, and the stored liquid air (N ₂ : 50 to 70%, O ₂ : 30) at the bottom of the rectification tower 12 is used.
(~ 50%) 13 is fed through a pipe 18 with an expansion valve 17a controlled by a liquid level gauge 17 to vaporize the nitrogen component, which is a high boiling point component, to keep the internal temperature of the column 15 at an ultralow temperature. However, it itself becomes an oxygen-rich ultra-low temperature liquid and accumulates at the bottom of the column 15. Due to the cold heat of the oxygen-rich ultra-low temperature liquid, the nitrogen gas fed into the condenser 16 is liquefied and, as described above, the introduction path pipe 14
It joins the liquid nitrogen in a. 30 is the nitrogen content accumulated in the upper part of the oxygen condensing tower 15 (purity is not so high)
With a waste nitrogen gas extraction pipe that takes out as waste nitrogen gas,
The waste nitrogen gas is guided to the first heat exchanger 8 to cool the raw material air to an ultra-low temperature by its cold heat, and then a part thereof is
The waste nitrogen gas, which has been heat-exchanged, is guided to the upper open type cooling cylinder 6b of the pair of cooling cylinders 6 and brought into contact with water flowing in a shower from the tip nozzle of the pipe 34 to cool the waste nitrogen gas. The waste nitrogen gas is discharged into the atmosphere as indicated by an arrow D, and the rest of the waste nitrogen gas is directly discharged through the branch pipe 30a into the atmosphere as indicated by an arrow A. In this case, a part of the waste nitrogen gas sent to the cooling cylinder 6 is the above-mentioned two pieces.
It is used to regenerate the adsorption cylinder of the set adsorption cylinder 7 that is not in adsorption operation. That is, the valve 38 is opened, and the ultra-low temperature waste nitrogen gas is sent to the waste heat recovery device 2 via the pipe 39 to raise the temperature, and then the regeneration heater 41 further raises the temperature to normal temperature, and the adsorption operation is not performed. It is sent to the other adsorption cylinder to regenerate the molecular sieve, and then released into the atmosphere as indicated by arrow B. The molecular sieve has almost no adsorptive capacity at room temperature and exhibits excellent adsorptive capacity at ultra-low temperature.In the state of being regenerated as described above, the molecular sieve is still at room temperature and can exhibit adsorptive capacity. Absent. Therefore, immediately after flowing the waste nitrogen gas at room temperature, the valve 38
The valve 37 is closed, the ultra-low temperature waste nitrogen gas is caused to flow to cool the molecular sieve, and the used waste nitrogen gas is discharged as shown by the arrow B. The playback of the sheave is complete. In this way, a set of two adsorption tubes 7 are alternately regenerated and used. 35
Reference numeral a is an expansion valve controlled by the liquid level gauge 35. In addition,
In the upper open type cooling cylinder 6b, the water 31 cooled by the waste nitrogen gas collects at the bottom of the upper open type cooling cylinder 6b,
By the action of the motor 32, the raw material air sent to the upper part of the hermetically-sealed cooling cylinder 6a through the pipe 33 and flowing down from there in a shower shape to be sent from the air compressor 1 is cooled. Then, the cooled water 31 is returned to the upper open type cooling cylinder 6b by the action of the motor 32, and is cooled again by the cold heat of the waste nitrogen gas. Reference numeral 21 denotes a tray type oxygen rectification column, which is connected to the bottom of the oxygen condensing column 15 by a pipe 22 and takes in the oxygen-rich ultra-low temperature fluid accumulated at the bottom of the oxygen condensing column 15 by a pressure difference. It is becoming like this. 25
Is a liquid level gauge, 26 is an expansion valve controlled by the liquid level gauge 25, and 27 is an acetylene absorber, which absorbs and removes acetylene in the oxygen-rich ultra-low temperature fluid. 28 is a third heat exchanger for cooling the oxygen-rich ultra-low temperature fluid.
By the cooling by the heat exchanger 28, the oxygen-rich ultra-low temperature fluid is further cooled, and the expansion valve 2 is placed in the oxygen rectification column 21.
By the action of 6, when being taken in as a spray, the oxygen component is immediately liquefied and the nitrogen component is gasified, so that both are separated with high precision. Liquid oxygen is sent to the lower part of the oxygen rectification tower 21 from the liquid oxygen storage tank 23 as cold via an introduction pipe 23a, and a condenser 24 built in the oxygen rectification tower 21 is cooled. Then, the waste nitrogen gas fed into the condenser 24 from the upper portion of the oxygen condensing tower 15 is liquefied and returned to the reflux liquid retainer 15c of the oxygen condensing tower 15 via the pipe 15b. 29 is an oxygen rectification tower 2
1 is a pipe for sending the ultra-low temperature nitrogen gas accumulated in the upper part of 1 as the refrigerant of the heat exchanger 28, and 29b is a pipe for sending the nitrogen gas, which has finished its function as the refrigerant, to the first heat exchanger 8,
The end of the first heat exchanger 8 is connected to the waste nitrogen gas extraction pipe 30 so that the nitrogen gas that has finished heat exchange merges with the waste nitrogen gas. 29a is a check valve. Reference numeral 25a is a liquid level gauge provided in the oxygen rectification column 21, and 23b is a flow rate control valve controlled thereby. Liquid level gauge 25a
Controls not only the flow rate of liquid oxygen but also the flow rate of liquid nitrogen delivered from the liquid nitrogen storage tank 14 by controlling the flow rate control valve 14b, and an appropriate amount of cold is constantly sent to the rectification columns 12 and 21. I am trying to get in. Reference numeral 21a denotes an oxygen gas extraction pipe, which is used for retaining liquid oxygen 2 at the bottom of the oxygen rectification column 21.
The vaporized ultra-high-purity oxygen gas is taken out from 1c (purity 99.5%), guided into the first heat exchanger 8, and heat-exchanged with the compressed air fed into the first heat exchanger 8 to bring it to room temperature, and the product oxygen gas is taken out. It acts to feed it into the pipe 21b. Reference numeral 29c is a waste pipe for discarding the retained liquid oxygen 21c at the bottom of the oxygen rectification column 21, and the liquid oxygen is supplied to the second heat exchanger 10.
And then exchanges heat with the raw material air to cool the raw material air to an ultralow temperature, and then discharges it as indicated by arrow C. The accumulated liquid oxygen 21c contains impurities such as methane and acetylene, and these impurities are accumulated in the accumulated liquid oxygen 21c.
The waste pipe 29c is open at the bottom of the oxygen rectification column 21 because it is located on the lower side of the column. Numerals 42 and 44 are back-up system lines, and when the air compression system line fails, the valve 4
2a and 44a are opened, the liquid nitrogen in the liquid nitrogen storage tank 14 is evaporated by the evaporator 43 and sent to the main pipe 20 so that the supply of nitrogen gas is not interrupted, and the liquid nitrogen storage tank 23 has Liquid oxygen is vaporized by the evaporator 45 and sent to the main pipe 21b so that the supply of oxygen gas is kept constant. The alternate long and short dash line indicates the vacuum insulation box. This vacuum cool box blocks heat intrusion from the outside and further improves the purification efficiency.

This apparatus produces product nitrogen gas and oxygen gas as follows. That is, the air compressor 1
The air is compressed by, and the heat generated at this time is recovered by the waste heat recovery device 2. Then, the compressed air is supplied and cooled by the intercooler 3, and then compressed by the air compressor 4.
After further cooling by the aftercooler 5, it is fed into the hermetically-sealed cooling cylinder 6a and countercurrently contacted with the water cooled by the waste nitrogen gas to cool it. Next, this is sent to the adsorption cylinder 7, and H
₂ O and CO ₂ are removed by adsorption. Then, a part of the compressed air from which H ₂ O and CO ₂ have been adsorbed and removed is removed from the pipe 9
Is sent to the inside of the first heat exchanger 8 to be cooled to an ultra-low temperature, and the rest is sent to the second heat exchanger 10 via a branch pipe 11 to be cooled to an ultra-low temperature. It is put in the lower part of the distillation column 12. Then, this input compressed air is countercurrently contacted with the liquid nitrogen sent from the liquid nitrogen storage tank 14 into the rectification column 12 and the liquid nitrogen overflowed from the liquid nitrogen reservoir 12a to cool a part thereof. It is liquefied and stored at the bottom of the rectification column 12. In this process, due to the difference in the boiling points of nitrogen and oxygen (boiling point of oxygen-183 ° C, boiling point of nitrogen-196 ° C), oxygen, which is a high-boiling point component in the compressed air, is liquefied and nitrogen remains as a gas. And
Liquid air 13 having a large oxygen content is accumulated at the bottom of the rectification column 12. Then, take out the nitrogen that remains as the above gas 1
It is taken out from the reactor 9 and sent to the first heat exchanger 8 where it is heated to near room temperature and sent from the main pipe 20 as ultra-high purity product nitrogen gas. In this case, the liquid nitrogen from the liquid nitrogen storage tank 14 acts as a cold source for liquefying the compressed air, vaporizes itself, and is taken out from the take-out pipe 19 as a part of the product nitrogen gas. On the other hand, the liquid air accumulated at the bottom of the rectification column 12 is passed through the pipe 18 to the oxygen condensation column 1
5 is sprayed into the column 5 and flows down to the bottom of the column 15 while being in contact with the liquid nitrogen overflowing from the reflux liquid reservoir 15c. At this time, similarly to the above, due to the difference between the boiling points of nitrogen and oxygen, oxygen, which is a high-boiling point component, is liquefied and nitrogen remains as a gas, so that the oxygen concentration of the liquid air accumulated at the bottom of the column 15 is the rectification column 12 The oxygen concentration of the liquid air 13 in the above condition (O ₂ : 60
~ 80%). Next, the oxygen-rich liquid air 13 is adiabatically expanded by the expansion valve 26, and then sent to the acetylene absorber to remove acetylene, and then sent to the third heat exchanger for cooling to remove oxygen content. It is liquefied and separated (the nitrogen component remains as a gas), and then sent to the oxygen rectification column 21. Of the gas-liquid mixture sent to the oxygen rectification column 21, liquid oxygen accumulates at the bottom of the column, nitrogen gas accumulates at the upper part of the column 21, and then is sent to the third heat exchanger 28 via a pipe 29. It is put in and acts as a refrigerant, and then is sent to the waste nitrogen gas take-out pipe 30 through the first heat exchanger 8 to be discarded. Liquid oxygen is supplied as cold from the liquid oxygen storage tank 23 to the oxygen rectification tower 21, and is mixed with the liquefied and separated liquid oxygen to be collected at the bottom of the tower to cool the condenser 24 built in the oxygen rectification tower 21. To do. On the other hand, most of the nitrogen gas separated in the oxygen condensing tower 15 is taken out from the waste nitrogen gas take-out pipe 30, and is used as a refrigerant for the first heat exchanger 8 and for producing cooling water for the air cooling cylinder 6. It is used to regenerate the adsorption cylinder 7.
Then, the rest of the nitrogen gas is sent to the condenser 24 built in the oxygen rectification tower 21, cooled by liquid oxygen, liquefied, and recirculated into the reflux liquid reservoir 15c in the oxygen condensing tower 15. The liquid oxygen at the bottom of the oxygen rectification column 21 is not directly taken out as a product, but is taken out as a vaporized product (oxygen gas) from the product oxygen gas pipe 21a and heat-exchanged by the first heat exchanger 8. After that, it is sent out of the system as a room temperature product gas. In the liquid oxygen accumulated in the oxygen rectification column 21, the one in the vicinity of the bottom contains a large amount of impurities such as acetylene and methane, and therefore is discarded to the outside via the pipe 29c. In this way
High-purity nitrogen gas and oxygen gas can be simultaneously obtained by one apparatus.

FIG. 2 shows another embodiment. This apparatus removes the oxygen condensing tower, enlarges the oxygen rectification tower 21 and improves its function, and directly connects it to the nitrogen rectification tower 12 so that a part of the product nitrogen gas produced in the nitrogen rectification tower 12 is removed. It is fed into the first condenser 24 of the oxygen rectification tower to be cooled and liquefied to form a reflux liquid, and the liquid air accumulated at the bottom of the nitrogen rectification tower 12 is mixed with the liquid oxygen delivered from the liquid oxygen storage tank 23. It is fed into the oxygen rectification column 21 to liquefy and separate oxygen.
Then, a second condenser 48 is further provided in the oxygen rectification column 21, and the separated and generated waste nitrogen gas is used as its refrigerant,
The accuracy of the liquefaction separation for oxygen is improved. Reference numeral 50 is a liquid level gauge, and 49 is a valve controlled by the liquid level gauge 50. Since the other parts are the same as those in FIG. 1, the same parts are designated by the same reference numerals and the description thereof will not be repeated.

This device has the same effects as the device of FIG. 1, and also has the effect that the overall size can be reduced. In the embodiment of FIGS. 1 and 2, the pipe 1
The valves 14b and 23b of 4a and 23a can be independently controlled from the control of the liquid level gauge 25a. That is, the above-mentioned apparatus can continuously operate by using the refrigeration of only one of the liquid nitrogen storage tank 14 and the liquid oxygen storage tank 23 to produce both nitrogen gas and oxygen gas, and one refrigeration cannot be obtained for some reason. In such a case, the valves 14b and 23b can be immediately operated to continuously operate using only the other cold.

[0012]

As described above, the high-purity nitrogen and oxygen gas production apparatus of the present invention does not use an expansion turbine, but instead uses liquid nitrogen and liquid oxygen storage tanks that have no rotating parts. As a whole, there are no rotating parts and no failures occur. Moreover, while the expansion turbine is expensive, the storage tank for liquid nitrogen or the like is inexpensive and no special personnel are required. In addition, expansion turbine (driven by the pressure of gas evaporated from liquid air accumulated in the nitrogen rectification column)
Has a very high rotation speed (tens of thousands of revolutions / minute), and thus it is difficult to perform a fine follow-up operation with respect to load fluctuations (changes in the amount of product nitrogen gas taken out). Therefore, it is difficult to constantly change the supply amount of liquid air to the expansion turbine according to the change in the amount of product nitrogen gas, etc. taken out, and to constantly cool the compressed air, which is the raw material for manufacturing nitrogen gas, etc., to a constant temperature. As a result, the purity of the product nitrogen gas or the like obtained varies, and a low-purity product is frequently produced, and the purity of the product nitrogen gas or the like is generally low. This device uses a liquid nitrogen storage tank instead, and uses liquid nitrogen and liquid oxygen that can be finely adjusted in the supply amount as cold,
The load fluctuation can be closely followed, and nitrogen and oxygen gas with stable purity and extremely high purity can be produced. Therefore, the conventional refining device is unnecessary. Moreover, this device uses liquid nitrogen and liquid oxygen as cold and does not escape them after use, but rather wastes resources because it uses nitrogen and oxygen gas produced from air as raw materials to produce product gas. Does not occur. Moreover, since this device has both a liquid nitrogen storage tank and a liquid oxygen storage tank, even if both of them are used as cold at the same time,
Both nitrogen gas and oxygen gas can be produced by using either one as cold. Therefore, it is extremely convenient because it is possible to operate using only one of the above-mentioned colds which is easily available.

[Brief description of drawings]

FIG. 1 is a configuration diagram of an embodiment of the present invention.

FIG. 2 is a configuration diagram of another embodiment.

[Explanation of symbols]

 1 1st Air Compressor 4 2nd Air Compressor 7 Adsorption Column 8 1st Heat Exchanger 10 2nd Heat Exchanger 12 Nitrogen Fractionation Tower 14 Liquid Nitrogen Storage Tank 14a Inlet Pipe 15 Oxygen Condensation Tower 18 Pipe 19 Extraction Pipe 21 Oxygen Fractionation Tower 21a Oxygen Gas Extraction Pipe 22 Pipe 23 Liquid Oxygen Storage Tank 23a Introduction Pipe

Claims (2)

[Claims] 1. An air compression means for compressing air taken in from the outside, a removal means for removing carbon dioxide gas and water in the compressed air compressed by the air compression means, and a compression through this removal means. A heat exchange means for cooling the air to an ultra low temperature, a liquid nitrogen storage means for storing liquid nitrogen, and a part of the compressed air cooled to an ultra low temperature by the heat exchange means is liquefied to retain only nitrogen as a gas inside Nitrogen rectification column, liquid nitrogen in the liquid nitrogen storage means to introduce liquid nitrogen into the nitrogen rectification column as a cold source for compressed air liquefaction, and liquid vaporized after finishing the action as a cold source Both nitrogen and vaporized nitrogen retained in the nitrogen rectification tower are used as product nitrogen gas from the nitrogen rectification tower to take out a nitrogen gas withdrawal path, and the difference between the boiling points of nitrogen and oxygen for liquid air is used. And both An oxygen rectification column to be separated, a liquid air supply path for supplying the retained liquid air in the nitrogen rectification column into the oxygen rectification column, a liquid oxygen storage means for storing liquid oxygen, and the liquid oxygen storage means. The liquid oxygen introduction passage that leads the liquid oxygen in the inside to the oxygen rectification column as a cold source, and the oxygen gas separated by utilizing the difference in the boiling points of oxygen and nitrogen from the liquid air as a raw material and the action as a cold source are completed. An apparatus for producing high-purity nitrogen and oxygen gas, comprising an oxygen gas take-out path for taking out both of the vaporized liquid oxygen as product oxygen gas from the oxygen rectification column. 2. An air compression means for compressing air taken in from the outside, a removal means for removing carbon dioxide gas and water in the compressed air compressed by the air compression means, and a compression through this removal means. A heat exchange means for cooling the air to an ultra low temperature, a liquid nitrogen storage means for storing liquid nitrogen, and a part of the compressed air cooled to an ultra low temperature by the heat exchange means is liquefied to retain only nitrogen as a gas inside Nitrogen rectification column, liquid nitrogen in the liquid nitrogen storage means to introduce liquid nitrogen into the nitrogen rectification column as a cold source for compressed air liquefaction, and liquid vaporized after finishing the action as a cold source Both nitrogen and vaporized nitrogen retained in the nitrogen rectification tower are taken out from the nitrogen rectification tower as product nitrogen gas, and a nitrogen gas extraction path for liquid air to vaporize the nitrogen content and enrich it with oxygen content. Cardioid Oxygen condensing tower to be in a state, a liquid air supply path for supplying the retained liquid air in the nitrogen rectification tower into the oxygen condensing tower, and an oxygen concentrator for separating the two by utilizing the difference in boiling points of oxygen and nitrogen. Distillation tower, supply path for supplying oxygen-rich liquid air in the oxygen condensing tower into the oxygen rectification tower, liquid oxygen storage means for storing liquid oxygen, and liquid in the liquid oxygen storage means Liquid oxygen introduction path leading to the oxygen rectification column with oxygen as a cold source, and oxygen gas separated from the oxygen-rich liquid air as a raw material by utilizing the difference in boiling points of oxygen and nitrogen, and the action as a cold source A high-purity nitrogen and oxygen gas production apparatus comprising an oxygen gas take-out path for taking out both of the vaporized liquid oxygen as product oxygen gas from the oxygen rectification column.