JP3513667B2 - Air liquefaction separation method and apparatus - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air liquefaction separation method and apparatus, and more specifically, it introduces compressed, purified and cooled raw material air into a rectification column for liquefaction rectification separation to obtain oxygen gas as a product. The present invention relates to an air liquefaction separation method and apparatus for producing nitrogen gas, liquefied oxygen, liquefied nitrogen, argon and the like.

[0002]

2. Description of the Related Art FIGS. 6 and 7 are system diagrams showing an outline of a conventional air liquefaction separation apparatus for collecting oxygen gas as a product. In FIG. 6, the raw material air compressed by the compressor 1 is cooled by a cooler 2 and then water and carbon dioxide in the raw material air are adsorbed and adsorbed on an adsorbent such as molecular sieves for purification by adsorption. It is introduced into the equipment 3, then heat-exchanged with the return gas in the main heat exchanger 4, cooled to approximately the liquefaction temperature, and introduced from the pipe 5 to the lower part of the lower column 6 of the double rectification column.

In the raw material air introduced into the lower tower 6, nitrogen gas is separated at the top of the tower and oxygen-enriched liquefied air is separated at the bottom of the tower by the rectification operation in the lower tower 6. This oxygen-enriched liquefied air is led to a pipe 7 at the bottom of the tower, and introduced into the upper middle part of the upper tower 9 via an expansion valve 8.

On the other hand, the nitrogen gas at the top of the lower column is introduced into the pipe 10 and introduced into the main condenser evaporator 11, where it is heat-exchanged with liquefied oxygen described later and liquefied into liquefied nitrogen, which is introduced into the pipe 12. It A part of the liquefied nitrogen in the pipe 12 is introduced into the top of the upper tower 9 through the pipe 13 and the expansion valve 14, and the rest is in the pipe 15.
Is introduced at the top of the lower tower.

In the upper tower 9, liquefied oxygen is separated at the bottom of the tower and nitrogen gas is separated at the top of the tower by the rectification operation. This nitrogen gas is led to the pipe 16,
The main heat exchanger 4 exchanges heat with the raw material air, raises the temperature, and is discharged.

The liquefied oxygen at the bottom of the upper tower is introduced into the main condenser / evaporator 11 through a pipe 17, heat-exchanges with the nitrogen gas discharged from the top of the lower tower, and vaporizes into oxygen gas. Is introduced into the lower part of the upper tower, and a part of the oxygen gas is discharged as a product from the pipe 18 through the main heat exchanger 4. Further, a part of the liquefied oxygen is discharged from the pipe 20.

Further, in order to supply necessary cold to the whole system, an expansion turbine (not shown) is installed in the path of the pipe 5 or 10 to generate cold by adiabatic expansion.

In the air liquefaction / separation device for separating and collecting oxygen in this manner, hydrocarbons such as methane, ethane, propane, etc. contained in the raw material air, which have a risk of exploding in a high oxygen atmosphere, Hazardous substances that are difficult to be sufficiently removed by ordinary adsorption purification equipment 3 and conventional reversible heat exchangers are introduced into the rectification column together with the feed air, and most of them are in the liquefied oxygen at the bottom of the upper column. Will be concentrated in.

In the adsorption refining equipment 3, the carbon number is 4
The above hydrocarbons and acetylene can be almost completely removed, but methane, ethane, and propane are currently difficult to completely remove. Further, in the reversible heat exchanger, the vapor pressure amount of hydrocarbon at the cold end temperature of the heat exchanger is introduced into the rectification column together with the feed air.

For this reason, in the conventional apparatus, it is necessary to wash the wall surface with liquefied oxygen at all times so that the dangerous substance is not deposited on the wall surface of the main condenser / evaporator 11. The external system shown in FIG. In any of the main condenser evaporators 11 and 11 'of the internal system shown in FIG. 7, a large amount of liquefied oxygen is stored at the bottom of the upper tower 9 to increase the sub-margence S in the heat exchanger block (core). The oxygen flow rate (circulation ratio) was increased.

[0011]

However, if the submergence in the main condenser evaporator, that is, the liquid height of liquefied oxygen is increased as described above, the temperature of the liquefied oxygen in the lower part of the main condenser evaporator is affected by the liquid head. When the pressure of nitrogen gas, that is, the pressure of the lower tower is increased in order to increase the average temperature difference between liquefied oxygen and nitrogen gas, the pressure of the raw material air introduced into the lower tower, that is, the discharge pressure of the compressor. However, there is a problem that the operating cost is increased.

By the way, since the above-mentioned hydrocarbons generally have a high boiling point, they are concentrated in the liquefied oxygen at the bottom of the upper column by the rectification operation as described above. When the amount of each hydrocarbon is not higher than the vapor pressure of each hydrocarbon at the vaporization temperature of oxygen in the vaporizer, the hydrocarbons introduced into the main condensation evaporator do not accumulate and vaporize simultaneously with the vaporization of oxygen. Since it is entrained in the gas and is discharged as an impurity component of the product oxygen gas, it is not necessary to increase the submergence and wash the wall surface of the main condenser evaporator with liquefied oxygen.

In view of this, the present invention sets the amount of dangerous substances such as hydrocarbons such as methane, ethane and propane in the main condenser evaporator to be equal to or lower than the vapor pressure of each hydrocarbon at the vaporization temperature of oxygen. It is an object of the present invention to provide an air liquefaction separation method and apparatus that can solve the above-mentioned drawbacks of the prior art and reduce the operating cost.

[0014]

In order to achieve the above-mentioned object, the air liquefaction separation method of the present invention is a method in which raw air compressed, purified and cooled is mixed with a lower tower, an upper tower and a main condenser evaporator. in line cormorant cryogenic air separation process liquefaction rectification separation is introduced into rectification column, an upper column cleaning unit for cleaning and removing hydrocarbons oxygen gas rising said upper column at liquid oxygen to lower the upper column Provided on the lower part , before extracted from the upper part of the cleaning part
Most of the liquefied oxygen is supplied to the main condensing evaporator, and the main condensing evaporator heat-exchanges with the nitrogen gas separated into the lower tower top to vaporize the liquefied oxygen and vaporize the oxygen gas.
The scan was introduced at the bottom of the cleaning unit, hydrocarbons of the oxygen in the gas
The element is washed away with the rest of the liquefied oxygen to dissolve the hydrocarbons.
It is characterized in that out Rashirube liquefied oxygen or the upper bottoms forme.

Further, the air liquefaction / separation device of the present invention is a double refining system equipped with a lower tower, an upper tower, and a main condenser evaporator for converting raw material air that has passed through a raw material air supply system equipped with a compression equipment, a refining equipment and a cooling equipment. In an air liquefaction separation apparatus for introducing into a distillation column and performing liquefaction rectification separation , carbonized water in oxygen gas rising in the upper column
A cleaning unit for cleaning and removing the element with liquefied oxygen descending the upper tower is provided at the lower part of the upper tower , and the liquefied oxygen extracted from the upper part of the cleaning unit is provided between the upper part of the cleaning unit and the main condenser evaporator.
Is provided with a liquefied oxygen supply pipe for supplying most of the gas to the main condensation evaporator, and a nitrogen gas separated between the lower part of the cleaning section and the main condensation evaporator into the top part of the lower column in the main condensation evaporator. and the oxygen gas vaporized by heat exchange provided with an oxygen gas introduction pipe for introducing into the upper column, the oxygen gas
By removing the hydrocarbons of the
Liquefied oxygen forme is characterized in that a liquid oxygen outlet pipe for deriving from said upper bottoms.

Furthermore, the air liquefaction separation method of the present invention is a washing method.
Most of the liquefied oxygen extracted from the upper part of the
Is about 80% of the liquefied oxygen descending, and the liquefied oxygen derived from the upper tower bottom is
Separately installed and vaporized by introducing into a sub-condensing evaporator
To obtain an oxygen gas by, in the main reboiler-condenser
The liquid height of the liquefied oxygen is set to the heat exchanger block of the main condenser evaporator.
Characterized by setting it to 50% or less of the lock height
I am trying. Further, in the air liquefaction separation method of the present invention, the main condenser evaporator is installed separately from the lower tower and the upper tower, and the liquefied oxygen derived from the bottom of the upper tower is vaporized to obtain oxygen gas. A sub-condensing evaporator is provided, the liquefied oxygen supply pipe is provided with a flow rate control valve for adjusting the supply amount of liquefied oxygen, and the cleaning section is a plate plate or a plate.
Is a filler, and the main condenser evaporator is
A nitrogen gas flow path was installed in the liquefied oxygen extracted from the upper tower of the
It is characterized in that it is a type in which a digitized heat exchanger is immersed .

[0017]

[Operation] According to the above configuration, hydrocarbons do not concentrate above the dangerous concentration in the liquefied oxygen of the main condensing evaporator, so the sub-margence in the main condensing evaporator is reduced and the effect of liquid depth is reduced. It can be minimized, heat exchange efficiency is improved, and compressor power can be reduced.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in more detail based on the embodiments shown in the drawings. First, FIG. 1 shows a first embodiment of the present invention, and shows an embodiment having a configuration substantially similar to that of the air liquefaction separation device shown in FIG.
The same elements as those of the conventional apparatus are designated by the same reference numerals, and detailed description thereof will be omitted.

The apparatus of this embodiment is provided with a cleaning section 22 composed of a perforated plate or a packing material in the lower part of the upper tower 21, and the liquefied oxygen is extracted from the upper tower 21 at the upper part of the cleaning section 22 to mainly remove it. Liquefied oxygen supply pipe 24 that is supplied to the lower part of the condensation evaporator 23
An oxygen gas introduction pipe 2 for introducing oxygen gas vaporized in the main condenser evaporator 23 into the upper tower 21 below the cleaning section 22.
5 is provided, and a liquefied oxygen outlet pipe 26 for deriving liquefied oxygen is provided at the bottom of the upper tower 21.

The raw material air compressed by the compressor 1 at 5 kg / cm ² G, for example, 10,000 Nm ³ / h, is as described above.
After being refined in the adsorption purification equipment 3 through the cooler 2 and cooled in the main heat exchanger 4, it is introduced into the lower column 6 of the double rectification column and rectified in the lower column 6 and the upper column 21. . In the raw material air, although it depends on atmospheric conditions, under the general atmospheric conditions, at the outlet of the adsorption purification equipment 3, about 2 methane
ppm, ethane about 0.02 ppm, propane about 0.02
ppm is included.

The rectified and separated liquefied oxygen flows down from the lower end of the rectification stage 21a of the upper tower 21, and most of it is
For example, about 80% is extracted from the liquefied oxygen supply pipe 24 with its amount adjusted by the flow rate control valve 27 and is supplied to the main condensing evaporator 23 as an upward flow. Main condenser evaporator 2
The liquefied oxygen supplied to 3 undergoes heat exchange with the nitrogen gas led to the pipe 10 from the top of the lower tower 6, and the entire amount is vaporized to become oxygen gas, which passes through the oxygen gas introduction pipe 25 and becomes the upper portion. It is introduced at the bottom of tower 21. At this time, a small amount of methane, ethane, propane, etc. mixed in the liquefied oxygen is completely vaporized simultaneously with the liquefied oxygen and returned to the upper column 21 from the oxygen gas introduction pipe 25 together with the oxygen gas. In addition, a part of this oxygen gas is branched into a pipe 28,
It can also be led out via the main heat exchanger 4.

In the main condenser evaporator 23, it is desirable that all of the liquefied oxygen introduced is vaporized, but a part of the liquefied oxygen may be returned in the state of the liquid from the oxygen gas introduction pipe 25. In this case, the total amount of the unvaporized liquid and the liquid flowing down through the cleaning unit 22 is up to 20%.

In the washing section 22 of the upper tower 21, about 20% of the liquefied oxygen flowing down from the rectification stage 21a is used.
And the oxygen gas introduced from the oxygen gas introduction pipe 25 come into contact with each other, and hydrocarbons such as methane contained in the oxygen gas are dissolved in liquefied oxygen and flow down to the bottom of the upper tower. From the bottom of this upper tower, liquefied oxygen 2000 Nm ³
/ H is led out to the pipe 26, and is collected as liquefied oxygen as it is or as oxygen gas after being vaporized by an appropriate evaporation means.

As described above, the cleaning unit 2 is provided at the bottom of the upper tower 21.
2 is provided so that liquefied oxygen is extracted from the upper part of the cleaning part 22 and supplied to the main condensing evaporator 23, and oxygen gas vaporized in the main condensing evaporator 23 is introduced to the lower part of the cleaning part 22. With this configuration, the hydrocarbons contained in the rising oxygen gas can be taken into the falling liquefied oxygen and removed from the oxygen gas, and the amount of hydrocarbons in the rectification stage 21a of the upper column 21 can be increased. That is, the concentration of hydrocarbons in the liquefied oxygen supplied to the main condenser evaporator 23 can be maintained at the outlet concentration of the adsorption purification equipment 3 described above.

Accordingly, since the liquefied oxygen is vaporized in the main condensing evaporator 23 and the total amount of hydrocarbons is vaporized at the same time, the hydrocarbons are not accumulated in the main condensing evaporator 23, so that the sub-mergence is caused. It becomes unnecessary to wash the wall surface of the main condenser evaporator 23 with liquefied oxygen. This makes it possible to set the sub-mergence of the main condensing evaporator 23 to a small value, and it is possible to operate in a dry system in which the liquefied oxygen is completely vaporized at the core outlet of the oxygen passage of the main condensing evaporator 23. Can be lowered to the lower part of the main condenser evaporator 23.

That is, the liquid level of liquefied oxygen in the main condenser evaporator 23 is 50% of the total height of the main condenser evaporator core.
It can be set to the following values. For example, when the total core height is about 2000 mm, the sub-margence is 2000 m.
It is possible to reduce what was required about m to about 0 to 200 mm. Further, even when a straight tube type or the like is adopted as the main condensing evaporator, it is possible to operate with the liquid level simply lowered similarly.

As described above, by setting the sub-margence of the main condensing evaporator 23 to be small, the temperature rise due to the liquid depth of the liquefied oxygen in the main condensing evaporator 23 can be made small. The pressure of the nitrogen gas at the top of the lower column for heat exchange, that is, the raw material air compression pressure can be lowered, and the power consumption rate can be reduced.

FIG. 2 shows a second embodiment of the present invention, in which a sub-condensation vaporization is provided downstream of the liquefied oxygen outlet pipe 26 in the air liquefaction separation apparatus shown in the first embodiment via an expansion valve 31. In the sub-condensing evaporator 32, a liquefied oxygen is vaporized by using a nitrogen gas led from a lower tower top through a pipe 33 as a heat source in the sub-condensing evaporator 32 to obtain oxygen gas. The same elements as those of the device of the first embodiment are designated by the same reference numerals, and detailed description thereof will be omitted.

The liquefied oxygen 2000 Nm ³ / h led out from the bottom of the upper tower 21 to the liquefied oxygen lead-out pipe 26 is decompressed by the expansion valve 31, introduced into the sub-condensing evaporator 32, and introduced through the pipe 33. Heat exchange with nitrogen gas, 1980
Nm ³ / h is vaporized into oxygen gas, which is discharged from the pipe 34 through the main heat exchanger 4. Remaining liquefied oxygen 20N
m ³ / h is extracted from the pipe 35 together with the hydrocarbon concentrated in the liquefied oxygen.

On the other hand, the nitrogen gas introduced from the pipe 33 into the sub-condensation evaporator 32 is heat-exchanged with the liquefied oxygen to be liquefied into liquefied nitrogen, which is led out to the pipe 36 and then the pipe 12
Combine with liquefied nitrogen from.

At this time, since the hydrocarbons are concentrated in the liquefied oxygen introduced into the sub-condensing evaporator 32,
It is necessary to wash the wall surface of the sub-condensing evaporator 32 with liquefied oxygen,
Although it is necessary to increase the sub-margence, by decompressing the liquefied oxygen with the expansion valve 31 and introducing it into the sub-condensation evaporator 32, a temperature difference between the liquefied oxygen at the lower part of the core and the nitrogen gas at the top of the lower column is secured. Therefore, liquefied oxygen can be sufficiently vaporized with nitrogen gas having a lower pressure than in the conventional case, and it is not necessary to increase the raw material air compression pressure.

Further, by providing the sub-condensing evaporator 32 to obtain oxygen gas, it is possible to arbitrarily select the heat source for vaporizing the liquefied oxygen, for example, the lower part of the lower column. It is also possible to use part of the raw material air introduced into the equipment, gas from other lines, and other equipment. The liquid surface pressure of the liquefied oxygen may be set to an appropriate pressure for heat exchange according to the composition and pressure of the gas serving as the heat source, and when decompression is not required, the expansion valve 31
Can be omitted, and the sub-condensing evaporator 32 can be installed at the bottom of the lower tower.

3 to 5 show another embodiment of the flow of oxygen in the main condenser evaporator part. As shown in FIG. 3, the liquefied oxygen reservoir 42 is provided below the rectification stage 41a of the upper tower 41.
The total amount of liquefied oxygen that has been rectified and separated is provided to the liquefied oxygen supply pipe 43, and a part of the liquefied oxygen, for example 20%, is supplied to the flow control valve 4
It is configured to branch into a pipe 45 having 4 and to be introduced into the upper portion of the cleaning unit 46. The liquefied oxygen vaporized in the main condensing evaporator 47 is introduced from the pipe 48 to the lower part of the cleaning section 46, and is cleaned with the liquefied oxygen in the cleaning section 46, and then the pipe 4
9 is introduced into the lower part of the rectification stage 41a.

In the system shown in FIG. 4, a gas-liquid separator 53 is connected in the middle of a liquefied oxygen supply pipe 51 via a flow rate control valve 52, and liquefied oxygen at the bottom of the gas-liquid separator 53 is mainly condensed by a pipe 54. The liquefied oxygen supplied to the evaporator 55 and vaporized in the main condenser evaporator 55 is introduced from the pipe 56 to the upper part of the gas-liquid separator 53, and the washing part provided from the top to the lower part of the upper tower 58 via the pipe 57. It is designed to be installed at the bottom of 59.

In FIG. 5, the main condenser evaporator 61 is
The heat exchanger 63 provided with a nitrogen gas flow path is immersed in the liquefied oxygen in the container 62, and the liquefied oxygen extracted from the upper part of the cleaning section 65 of the upper tower 64 is
6, the oxygen gas supplied into the container 62 through the valve 67 and vaporized in the container 62 is supplied from the pipe 68 at the top of the container to the cleaning unit 6
Introduced at the bottom of 5.

Tables 1 to 3 compare the apparatus shown in the second embodiment with the conventional apparatus shown in FIG. 6, and Table 1 shows operating conditions and hydrocarbon concentration in liquefied oxygen. Table 2 shows operating conditions of the main condenser evaporator,
Table 3 shows the operating conditions of the sub-condensing evaporator.

The sub-mergence in the main condenser evaporator is 0 mm in the apparatus of the example and 200 in the apparatus of the conventional example.
0 mm, the liquid surface pressure is 0.6 kg / cm ² G for both
And The pressure loss from the compressor to the top of the lower tower was 4000 mmAq.

[0038]

[Table 1]

[Table 2]

[Table 3]

As shown in Table 1, in the case of the apparatus of this embodiment, the hydrocarbon concentration in the liquefied oxygen of the main condenser evaporator is the concentration at the vapor pressure of each hydrocarbon under the conditions of the embodiment, that is, methane 1
Since it is 1 vol%, ethane 18 vol ppm, and propane 0.07 vol ppm or less, it is not necessary to wash the wall surface of the heat exchanger with liquefied oxygen, and the submergence can be reduced.

As shown in Table 2, in the case of the device of this embodiment, the sub-margence of the main condenser evaporator can be reduced to reduce the temperature rise of liquefied oxygen in the lower part of the main condenser evaporator core. Even if the difference is made small, the temperature difference between the liquefied oxygen and the nitrogen gas in the lower part of the core can be sufficiently made, and the temperature of the nitrogen gas can be made lower than the conventional temperature. As a result, the nitrogen gas pressure at the top of the lower column can be lowered, so that the raw material air discharge pressure of the compressor can be lowered, and the power cost of the compressor can be reduced.

Further, as shown in Table 3, since the liquefied oxygen is decompressed and introduced into the sub-condenser, even if the sub-margence becomes large and the temperature of the liquefied oxygen rises in the lower part of the core, the above condition is satisfied. Since a sufficient temperature difference can be obtained by using the nitrogen gas as it is, heat exchange efficiency is not impaired.

[0042]

As described above, according to the present invention,
Since it is possible to prevent hydrocarbons from concentrating above the dangerous concentration in the liquefied oxygen in the main condensing evaporator, it is not necessary to wash the walls of the main condensing evaporator with liquefied oxygen, and the sub-mergence in the main condensing evaporator is reduced. The influence of the liquid depth can be minimized, the heat exchange efficiency can be improved and the nitrogen gas pressure can be lowered, and the operating cost can be reduced by reducing the power of the compressor that pressurizes the raw material air. Further, the cleaning section can be easily formed by forming it with a perforated plate or a filler.

[Brief description of drawings]

FIG. 1 is a system diagram of an air liquefaction separation device showing a first embodiment of the present invention.

FIG. 2 is a system diagram of an air liquefaction separation device showing a second embodiment of the present invention.

FIG. 3 is a system diagram showing another embodiment of the flow of oxygen in the main condenser evaporator portion.

FIG. 4 is a system diagram showing still another embodiment.

FIG. 5 is a main part systematic diagram showing still another embodiment.

FIG. 6 is a system diagram showing an example of a conventional air liquefaction separation device.

FIG. 7 is a main part system diagram showing another example of a main condenser evaporator.

[Explanation of symbols]

1 ... Compressor, 2 ... Cooler, 3 ... Adsorption refining equipment, 4 ... Main heat exchanger, 6 ... Lower tower, 21 ... Upper tower, 21a ... Fractionation stage,
22 ... Washing part, 23 ... Main condensing evaporator, 24 ... Liquefied oxygen supply pipe, 25 ... Oxygen gas introduction pipe, 26 ... Liquefied oxygen derivation pipe,
27 ... Flow control valve, 31 ... Expansion valve, 32 ... Sub-condensing evaporator

─────────────────────────────────────────────────── ─── Continuation of the front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) F25J 1/00-5/00

Claims (10)

(57) [Claims] 1. A compression, purification, the cooled feed air, the lower column, an upper column, in the row cormorants cryogenic air separation process liquefaction rectification separation is introduced into Fukusei column having a main condenser evaporator, said Hydrocarbons in oxygen gas rising in the upper tower descending in the upper tower
A washing part for removing by washing with liquefied oxygen is provided in the lower part of the upper tower , and most of the liquefied oxygen withdrawn from the upper part of the washing part.
It was fed to the main reboiler-condenser, the under main condenser evaporator
The liquefied oxygen is vaporized by exchanging heat with the nitrogen gas that separates to the top of the column , and the vaporized oxygen gas is introduced into the lower part of the cleaning unit, and the hydrocarbon in the oxygen gas is converted into the liquefied oxygen.
Was washed away with the rest, cryogenic air separation process, characterized by leaving Rashirube liquefied oxygen that dissolved hydrocarbons or the upper column bottom. 2. A large amount of liquefied oxygen extracted from the upper part of the cleaning section.
A portion is about 80% of the liquefied oxygen descending the upper tower.
The method of cryogenic air separation according to claim 1, wherein the that. 3. The oxygen gas is obtained by introducing the liquefied oxygen derived from the bottom of the upper tower into a sub-condensing evaporator installed separately from the main condensing evaporator to vaporize the liquefied oxygen. The air liquefaction separation method according to 1 or 2. The 4. A liquid level of the liquid oxygen in the main condenser evaporator 1 through claim and sets than 50% of the height of the heat exchanger block of the main reboiler-condenser
The air liquefaction separation method according to any one of 3 above. 5. The raw material air that has passed through a raw material air supply system equipped with a compression facility, a refining facility, and a cooling facility is supplied to a lower tower, an upper tower,
In an air liquefaction separation apparatus for introducing into a double rectification column equipped with a main condenser evaporator and performing liquefaction rectification separation, the upper column is raised.
A cleaning unit for cleaning and removing hydrocarbons in oxygen gas with liquefied oxygen descending the upper tower is provided at the lower part of the upper tower , and between the upper part of the cleaning unit and the main condenser evaporator, from the upper part of the cleaning unit. Pull out
Most of the liquid oxygen that issued provided liquefied oxygen supply pipe for supplying to the main condenser evaporator, between the main reboiler-condenser and the lower portion of the cleaning part, the lower tower top at main condenser evaporator
With nitrogen gas and the oxygen gas vaporized by heat exchange to separate providing an oxygen gas introduction pipe for introducing into the upper tower, to wash and remove hydrocarbons of the oxygen in the gas
Ri, liquefied oxygen that dissolved hydrocarbons or the upper bottoms
Cryogenic air separation unit, characterized in that a liquid oxygen outlet pipe for al derived. 6. The main condenser / evaporator is installed separately from the lower tower and the upper tower.
The air liquefaction separation device described. 7. A cryogenic air separation unit according to claim 5 or 6, characterized in that it comprises a sub-condenser evaporator to obtain the liquefied oxygen is vaporized oxygen gas derived from the upper column bottom. Wherein said liquid oxygen feed pipe, air separation plant of any one of claims 5 to 7, characterized in that it comprises a flow control valve for adjusting the liquid oxygen supply. 9. The cleaning unit is composed of a perforated plate or a filler.
9. The method according to any one of claims 5 to 8, characterized in that
Air liquefaction separation device . 10. The main condenser evaporator is an upper tower in a vessel.
Liquefied oxygen extracted from the heat exchanger with a nitrogen gas flow path
6. The method according to claim 5, characterized in that the converter is immersed.
10. The air liquefaction separation device according to any one of 9 to 9 .