KR20110119106A - Apparatus for producing high purity oxygen and method for controlling the same - Google Patents

Abstract

PURPOSE: An apparatus for generating high purity oxygen and a method for controlling the same are provided to generate product gas based on remaining high purity oxygen in a carbon molecular sieve(CMS) tower. CONSTITUTION: An apparatus for generating high purity oxygen includes zeolite tower systems(5, 6), a compressor(8), a CMS tower system(10), and at least one storing tanks. The zeolite tower systems are in fluid-connection with a compressing unit and a decompressing unit. The zeolite tower systems absorb or desorb nitrogen by increasing or decreasing a pressure in a tower. The compressor is in fluid-connection with the zeolite tower systems and compresses resultants generated from the zeolite tower systems. The CMS tower system is in fluid-connection with the compressor and generates oxygen. The storing tanks store oxygen from the zeolite tower systems and the CMS tower system.

Description

Apparatus for producing high purity oxygen and method for controlling the same}

The present invention relates to a high-purity oxygen production apparatus and a control method thereof, and more particularly, to a high-purity oxygen production apparatus and a control method for producing high-purity oxygen gas by using vacuum desorption of the CMS tower system at the time of oxygen production will be.

Currently, deep cooling, adsorption, membrane separation, etc. are mainly used as an industrial method for producing oxygen by separating air. Here, the deep cooling method is a process for compressing and purifying air, cooling it to a low temperature using a heat exchanger, and then separating it into pure gas through distillation, which is advantageous for large-scale separation. On the other hand, adsorption is mainly used for medium and small scales as the oxygen production method, and the membrane separation method is used for the production of less than 40% of oxygen or 90 to 99% of nitrogen with a small capacity. In addition, ITM method using absorption method and inorganic membrane for air separation is under development.

Among the above methods, the adsorption method is a method of separating elements using a material having fine pores corresponding to a specific element in air, and a representative example of the material may be zeolite. Zeolites exhibit strong adsorption performance for nitrogen in air and weak adsorption performance for oxygen. Accordingly, when air is supplied to the zeolite, nitrogen is adsorbed and oxygen is permeated and discharged to produce oxygen without nitrogen. Therefore, the general oxygen production system of the adsorption method is composed of a tower filled with zeolite, and also composed of two or more zeolite towers to increase the purity of oxygen.

However, the zeolite has a poor adsorption performance for argon contained in air, and permeates it with oxygen, so the purity of the separated oxygen is only about 93 to 95%. Accordingly, efforts have been made to increase the purity of oxygen produced through adsorption, and techniques have been developed in the United States and Japan to increase oxygen purity to 99.7% through adsorption. However, the technique requires separate adsorption processes for bulk separation and adsorption processes for purification. That is, in the above technique, after the bulk separation adsorption process is completely completed, the purification adsorption process is further performed again. Thus, since the two processes must be performed together, there is a problem in that the production cost becomes expensive.

On the other hand, it is also possible to produce nitrogen using the adsorption method, a representative adsorbent used at this time is a carbon (Moboncular Seive) CMS. Oxygen is adsorbed to the CMS at a rate of several tens to several hundred times faster than nitrogen and argon. CMS tower system is a system for producing nitrogen using this property, and may also be composed of two or more towers to increase the purity of the nitrogen produced.

Recently, a method of increasing the purity of oxygen by mixing two types of the above systems, first producing 93 to 95% of oxygen in a zeolite tower system, and filtering the produced oxygen in a CMS tower system again. However, the process is a simple multistage system in which separately configured zeolite tower systems and CMS tower systems are operated independently. As a result, the production cost and energy consumption increase in the above system, and the raw material has to go through each separate system separately, so that the oxygen recovery rate is lowered.

On the other hand, the Republic of Korea Patent No. 605549 is connected to the air pressurizing means and decompression means, consisting of a zeolite tower system for producing oxygen and the CMS tower system for absorbing the oxygen produced in the system, and producing oxygen under reduced pressure An oxygen production apparatus and a control method thereof are disclosed. However, the above technology has a disadvantage in that the purity and recovery rate of product gas (oxygen) are lowered due to the following problems. That is, in the technology of the Korean patent, (1) the pressure equalization (pressure equalization) process is performed in a state where the desorption line valve of the zeolite tower system is closed, so that the nitrogen gas adsorbed on the upper part of the zeolite tower in the equalization process is different from the top of the zeolite tower. Can be instantaneously introduced into the furnace, and the nitrogen gas component adsorbed at the bottom is not easily desorbed; (2) the desorption of the CMS tower system is carried out at low pressure, so that the adsorbent cannot be sufficiently regenerated, and (3) the oxygen-rich gas discharged from the CMS tower is pressurized with the desorption line valve of the zeolite tower system closed. As a result, the nitrogen content inside the tower is poorly discharged. In addition, the above-described Korean patent (4) has a problem that the process of removing nitrogen and argon remaining in the CMS column is inefficient and difficult to control.

In order to solve this problem, Korean Patent Application No. 10-2007-0106805 discloses an oxygen production apparatus and a control method to improve the above matters, and solves most problems of Korean Patent No. 605549.

The product oxygen production method in the patent pressurizes 93% oxygen produced in the zeolite system to the CMS tower system using an O ₂ Compressor to adsorb oxygen and produces high purity product oxygen at reduced pressure desorption. Here, the characteristics of the CMS packed into the CMS tower system, the oxygen containing the high purity or trace amounts of argon and nitrogen in the initial decompression desorption for about 1 to 5 seconds as adsorbed at a rate of several tens to several hundred times faster than the argon or nitrogen As oxygen is produced and decompression desorption proceeds, oxygen is produced that contains little argon and nitrogen to produce oxygen of higher purity at the end of the decompression desorption.

 However, in the above patent, the CMS tower production line and the storage tank (Gas Holder) are fluidly connected so that the storage tank is filled with product oxygen when the CMS tower is depressurized and desorbed. The pressure in the CMS tower, which is in fluid connection with the tank, is also present at the end of the decompression desorption. Therefore, the high-purity oxygen remaining in the CMS tower at the end of the desorption desorption cannot take the product oxygen as a product oxygen.

Accordingly, an object of the present invention is to solve the problems of the prior art as described above, and to be able to take the high-purity oxygen remaining in the CMS tower during production of oxygen as product oxygen.

Technical problems to be achieved by the present invention are not limited to the above-mentioned technical problems, and other technical problems not mentioned above will be clearly understood by those skilled in the art from the following description. Could be.

According to a feature of the present invention for achieving the above object, the present invention is a zeolite tower system that is in fluid communication with the pressurizing means and the decompression means to increase or decrease the pressure inside the tower to adsorb or desorb nitrogen; A compressor in fluid communication with the zeolite tower system to compress a product produced from the zeolite tower system; A CMS tower system in which the oxygen is produced by vacuum desorption through a line in fluid communication with the front end of the compressor after adsorbing oxygen in the compressed product in fluid communication with the compressor; At least one storage tank capable of storing oxygen discharged from the zeolite tower system and the CMS tower system.

According to another feature of the present invention, the present invention provides a high purity oxygen production apparatus including a primary tank and a secondary zeolite tower, a CMS tower and a storage tank for storing a product produced in the primary and secondary zeolite towers. In the method for controlling the pressure, the primary zeolite tower is pressurized by the supply of raw material gas, vacuum desorption is carried out in the secondary zeolite tower, the product stored in the storage tank is supplied to the CMS tower and pressurized And a first step of performing adsorption; Pressurizing the first zeolite tower by supplying the source gas to adsorb nitrogen, and supplying the product generated in the first zeolite tower to the CMS tower to perform pressurization and adsorption; Pressurizing the first zeolite tower to adsorb nitrogen, and introducing a gas discharged from the decompressed CMS tower through the open valve into the source gas supply stage; A fourth step of pressurizing the first zeolite tower to adsorb nitrogen, and the gas discharged under reduced pressure from the CMS tower flows into the second zeolite tower to be cleaned; The first zeolite tower is pressurized to adsorb nitrogen, and the second zeolite tower is desorbed in vacuum, and the CMS tower is connected to the front of the compressor and decompressed to vacuum, and the high purity oxygen gas is the rear of the compressor. A fifth step of producing product gas after being stored in a storage tank connected to the storage tank; Comprising a sixth step of performing the equalization process after the adsorption of the first zeolite tower is finished.

In the present invention, the lower line of the CMS tower is fluidly connected to the front end of the compressor is carried out fluid control using an automatic valve. Therefore, by using vacuum desorption using a compressor during desorption in the CMS tower, there is an effect of producing high purity oxygen remaining in the CMS tower as a product gas during oxygen production.

1 is a schematic view showing a high purity oxygen production apparatus according to an aspect of the present invention.
2 to 7 is a schematic diagram showing a driving state of the high purity oxygen production apparatus according to an aspect of the present invention.

Hereinafter, exemplary embodiments of a high purity oxygen production apparatus and a control method thereof according to the present invention will be described in detail with reference to the accompanying drawings.

High purity oxygen production apparatus of the present invention is a ZMS tower system or CMS consisting of a zeolite tower filled with a zeolite (hereinafter referred to as 'ZMS') (hereinafter referred to as 'ZMS tower') or a CMS tower filled with a CMS therein It includes a tower system. As used herein, the term "top system" means a device comprising one or two or more towers interconnected vertically or horizontally. At this time, the type and structure of the ZMS tower or CMS tower that can be used is not particularly limited, it is possible to use all of the general ZMS tower or CMS tower in this field. Hereinafter, the ZMS tower or CMS tower may be used as the same meaning as the ZMS tower system or the CMS tower system, respectively.

The attached Figure 1 shows one aspect of the oxygen production apparatus of the present invention. That is, in the present invention, it is preferable that the ZMS tower system of the oxygen production apparatus includes two ZMS towers 5 and 6 of the first and the second, and the CMS tower system includes one CMS tower 10. Do. In this case, the oxygen production process may be performed while repeatedly changing the driving states of the first and second ZMS towers 5 and 6. However, the configuration of the tower system as described above is only one example of the present invention, and in the present invention, various combinations of the tower system may be employed as necessary.

Referring to the accompanying drawings, an embodiment of the oxygen production apparatus configuration of the present invention will be described in detail.

As shown in FIG. 1, in the oxygen production apparatus of the present invention, the ZMS tower systems 5 and 6 and the CMS tower system 10 are organically connected to each other to allow fluid flow therebetween. Accordingly, the product discharged from the ZMS tower systems 5 and 6 may be introduced into the CMS tower system 10 to proceed with oxygen adsorption, and the oxygen-rich gas discharged from the CMS tower system 10 may be selectively selected. This can be used for the step-up, washing and recovery processes of the ZMS tower systems 5 and 6.

The oxygen production apparatus of the present invention is also in fluid connection with the ZMS tower system 5, 6 and the CMS tower system 10, after compressing the product of the ZMS tower system 5, 6, the compressed product is converted into the CMS column. It may further comprise a compressor 8 which may be introduced into the system 10.

In addition, in the present invention, the upper line of the ZMS tower system 5, 6 is in fluid connection with a compressor 8 capable of compressing the upper product of the ZMS tower system, and the lower line is pressurized means 2 and depressurization. It is preferably in fluid connection with the means 12. The apparatus of the present invention is also in fluid communication with the top line of the ZMS tower system 5, 6 and the compressor 8 so as to store the top product of the ZMS tower system 5, 6 and then all or part of the compressor ( A storage tank 7 which can be transferred to 8); And a storage tank 9 fluidly connected with the compressor 8 and the lower line of the CMS tower 10 to store the compressed product in the compressor 8 and then transfer the same to the CMS tower 10. can do. Specific types of compressors and storage tanks used at this time are not particularly limited, and a general compressor or storage tank in this field may be used without limitation.

In addition, the pressurization means in the above means a means capable of supplying a source gas such as air into the ZMS tower system (5,6). In the present invention, as long as it can play the above role, the specific kind of pressurization means is not particularly limited, and for example, a conventional air pressurization means such as a blower 2 or a pressurizer can be used. The gas passing through the blower 2 is introduced into the first ZMS tower 5 through the heat exchanger 3.

In addition, the decompression means serves to reduce the internal pressure to an atmospheric pressure or a vacuum state by inhaling air and the like in the system, and the specific type thereof is not particularly limited as long as it can perform such a role. For example, in the present invention, general air decompression means in this field, such as vacuum pump 12, can be used.

When the source gas such as air is injected into the ZMS towers 5 and 6 by the above pressurizing means and pressurized, the ZMS filled therein adsorbs nitrogen in the source gas. In addition, when the pressure inside the ZMS towers 5 and 6 is reduced by the decompression means, the adsorbed nitrogen is desorbed (desorbed and removed). Although not particularly limited, in the present invention, it is preferable that the ZMS tower systems 5 and 6 include a plurality of ZMS towers, and alternately perform pressurization and depressurization processes in each ZMS tower. For example, when the ZMS tower system 5, 6 of the present invention includes the first and second towers as shown in Figure 1, when the first ZMS tower 5 is pressurized When the secondary ZMS tower 6 is in a reduced pressure state, on the contrary, when the secondary ZMS tower 6 is in a pressurized state, it is preferable that the primary ZMS tower 5 is controlled to be in a reduced pressure state.

In addition, the CMS tower system 10 of the oxygen production apparatus of the present invention is in fluid connection with a storage tank 11 whose lower line can store the product discharged from the compressor 8 and the CMS tower system 10 described above. It is preferable that it is done. With the configuration as described above, the CMS tower system 10 may be discharged from the upper line of the ZMS tower system 5, 6 to receive the product compressed by the compressor (8) to perform an oxygen adsorption process. In addition, by connecting the lower line of the CMS tower system 10 and the storage tank 11, the oxygen produced by reducing the internal pressure of the CMS tower system 10 may be stored in the storage tank 11.

The CMS tower system 10 of the present invention also has its top and bottom lines further fluidly connected with the ZMS tower systems 5, 6, and its top line is further fluidly connected with the storage tank 11. It is desirable to have. By configuring as described above, it is possible to perform the step-up, cleaning and recovery of the CMS tower and ZMS tower system using all or part of the product gas stored in the storage tank (11).

On the other hand, in the present invention, the lower line of the CMS tower system 10 is in fluid communication with the front end of the compressor (8) is carried out fluid control using an automatic valve. In addition, the rear end of the compressor 8 is in fluid communication with the storage tank 11. Therefore, by performing vacuum desorption using the compressor 8 at the time of desorption of the CMS tower 10, high purity oxygen remaining in the CMS tower 10 at the time of production of oxygen can be taken as product oxygen.

In the oxygen production apparatus described above, the ZMS tower system, the CMS tower system, the compressor, the storage tank, and the like are preferably interconnected by connecting means such as a pipe including a valve capable of controlling the fluid flow. The valve is controlled to be properly opened or closed according to the pressure state inside each tower system, the gas storage amount and / or purity in the storage tank, and thus, may serve to control the operating state of the oxygen production apparatus. By controlling the device through the valve which can be opened and closed in this way, in the present invention, it is possible to easily produce high-purity oxygen at an appropriate time as needed.

Hereinafter, with reference to the accompanying drawings will be described in detail a control method of the high-purity oxygen production apparatus according to the present invention. 2 to 7 is a schematic diagram showing a driving state of the high purity oxygen production apparatus according to an aspect of the present invention.

As shown in FIG. 2, in the first step of the present invention, the first ZMS tower 5 is only subjected to a pressing process. In the second ZMS column 6, vacuum desorption is performed. The desorption is the second ZMS tower 6 is decompressed by the vacuum pump 12 in a state in which the valves 3 and 19 are opened to allow the desorption to proceed.

In addition, the oxygen gas stored in the storage tank 7 is pressurized and stored in the storage tank 9 through the compressor 8, and the oxygen gas pressurized and stored in the storage tank 9 is similar to the first step. Pressurized by the CMS tower 10, the CMS tower 10 is to be pressed and adsorption.

Next, referring to FIG. 3, in the second step of the present invention, the source gas is supplied from the source gas supply device 1 through the open first valve, whereby the first ZMS tower 5 is nitrogen. Adsorption process is performed. In addition, the oxygen gas which is not adsorbed in the first ZMS tower 5 is stored in the storage tank 7 through the open valve 7.

In addition, desorption proceeds by depressurizing the secondary ZMS column 6 and gas is pressurized from the storage tank 7 to the CMS column 10 in the same manner as described above.

Next, referring to FIG. 4, in the third step of the present invention, the first ZMS tower 5 is adsorbed as described above, and the oxygen gas which is not adsorbed is opened as in the fourth step. Is stored in the storage tank 7 through. The oxygen gas stored in the storage tank 7 is pressurized and stored in the storage tank 9 through the compressor 8, and the secondary ZMS tower 6 is depressurized to proceed with desorption.

In addition, the CMS tower 10 is depressurized through the open valve 17. At this time, since the low purity oxygen gas that is not adsorbed is rich in oxygen, it is introduced into the source gas supply stage, that is, the front end of the blower 2 through the open valve 12, and the adsorption is performed again.

Next, referring to FIG. 5, in the fourth step of the present invention, adsorption is carried out in the first ZMS tower 5 as in the third step, and oxygen gas is pressurized and stored in the storage tank 9. The secondary ZMS tower 6 is depressurized and desorption proceeds.

Meanwhile, the CMS tower 10 is depressurized through the open valve 17. Unlike the third step, the gas discharged under reduced pressure is introduced into the second ZMS tower 6 through the open valve 10. And cleaning is performed. The gas which has been cleaned is exhausted as waste gas through the vacuum pump 12.

Next, referring to FIG. 6, in the fifth step of the present invention, adsorption is performed in the first ZMS tower 5 in the same manner as in the third and fourth steps, and oxygen gas is pressurized to the storage tank 9. And the secondary ZMS tower 6 is decompressed to proceed with desorption.

In addition, the CMS tower 10 was depressurized by vacuum through a valve 16 connected to the front end of the compressor 8, and was adsorbed through a valve 22 connected to the rear end of the compressor 8 and the storage tank 11. The high purity oxygen gas is stored in the storage tank 11 and then produced as a product gas.

Next, referring to FIG. 7, in the sixth step of the present invention, adsorption of the first ZMS tower 5 ends, and the oxygen-rich gas in the first ZMS tower 5 is transferred to the second ZMS tower ( 6), equalization process is performed. At this time, the valves 2 and 3 are opened to smooth the equalization process. The equalization process is preferably carried out in a state in which the desorption lines of the ZMS towers 5 and 6 are open. In the sixth step, the CMS tower 10 is decompressed to a vacuum to store high purity oxygen gas in the storage tank 11 to produce the product gas.

The driving process of the oxygen production apparatus described above shows a step of producing oxygen while the pressure and adsorption of the first ZMS tower 5 and the decompression and desorption processes of the second ZMS tower 6 are performed. According to the control method of the present invention, it is possible to continuously perform the oxygen production process by replacing the roles of the first and second ZMS towers 5 and 6 following the first to sixth steps. That is, in the present invention, the oxygen production process is performed by inducing the depressurization and desorption in the first ZMS tower 5 and the pressurization and adsorption in the second ZMS tower 6 after the above-described steps. In this case, the driving process is similar to the first to sixth steps described above, which will be referred to Table 2 below.

Table 1 below summarizes the first to sixth steps described above, and Table 2 changes the roles of the first and second ZMS towers 5 and 6 to the seventh to twelfth steps. It is summarized.

(PR: pressurized, AD: adsorption, DE: reduced pressure, VU: vacuum desorption, PU: washing, PE: equal pressure) First stage 2nd step 3rd step 4th step 5th step 6th step 1 ^st ZMS PR AD PE 2 ^nd ZMS VU PU VU PE CMS PR, AD DE VU Release valve 1,3,14,19,
20,21 1,3,7,14,19,20,21 1,3,7,12,14,17,19,20,21 1,3,7,10,14,
17,19,20,21 1,3,7,16,
19,22 2,3,6,16,19,22

(PR: pressurized, AD: adsorption, DE: reduced pressure, VU: vacuum desorption, PU: washing, PE: equal pressure) 7th Step 8th step 9th Step 10th step 11th Step 12th Step 1 ^st ZMS VU PU VU PE 2 ^nd ZMS PR AD PE CMS PR, AD DE VU Release valve 2,4,14,19,
20,21 2,4,8,14,19,20,21 2,4,8,12,14,17,19,20,21 2,4,8,9,14,
17,19,20,21 2,4,8,16,
19,22 2,3,6,16,19,22

In the present invention, the oxygen production process may proceed while continuously repeating the set of processes shown in Tables 1 and 2. At this time, the number of repetitions is not particularly limited and may be appropriately selected according to the desired production amount.

The scope of the present invention is not limited to the embodiments described above, but is defined by the claims, and various changes and modifications can be made by those skilled in the art within the scope of the claims. It is self evident.

For example, the present invention has been described with reference to an aspect of the high purity oxygen production apparatus of the present invention including two ZMS towers and one CMS tower, but is not limited thereto, and three or more ZMS towers and / or two as necessary. Even when more than one CMS tower is included, the same principle as described above may be used to proceed with the oxygen production process.

1: raw material gas supply device 2: blower
3: heat exchanger 5: primary zeolite tower
6: second zeolite tower 7,9,11: storage tank
8 compressor 10 CMS tower
12: vacuum pump AV: valve

Claims (13)

A zeolite tower system in fluid communication with the pressurizing means and the decompression means to adsorb or desorb nitrogen by increasing or decreasing the pressure inside the tower;
A compressor in fluid communication with the zeolite tower system to compress a product produced from the zeolite tower system;
A CMS tower system in which the oxygen is produced by vacuum desorption through a line in fluid communication with the front end of the compressor after adsorbing oxygen in the compressed product in fluid communication with the compressor;
High purity oxygen production apparatus comprising at least one storage tank capable of storing the oxygen discharged from the zeolite tower system and the CMS tower system. The method of claim 1,
The zeolite tower system comprises two primary and secondary zeolite towers, and the CMS tower system comprises one CMS tower. The method of claim 2,
The upper line of the zeolite tower system is in fluid communication with the compressor, and the lower line is in fluid communication with the pressurizing means and the decompression means. The method of claim 3, wherein
The upper and lower lines of the CMS tower system are further in fluid communication with the zeolite tower system, and the upper line is further in fluid communication with the storage tank. The method of claim 1,
The pressurizing means is a blower, the decompression means is a high purity oxygen production apparatus, characterized in that the vacuum pump. 6. The method according to any one of claims 1 to 5,
A lower line of the CMS tower system is in fluid communication with the front end of the compressor, and the rear end of the compressor is further in fluid communication with the storage tank. 1. A method of controlling a high purity oxygen production apparatus comprising a first and a second zeolite tower, a CMS tower and a storage tank for storing a product produced in the first and second zeolite towers.
The first zeolite tower is pressurized by supplying source gas, and the second zeolite tower is vacuum desorbed, and the product stored in the storage tank is supplied to the CMS tower to pressurize and adsorb the first zeolite column. Steps;
Pressurizing the first zeolite tower by supplying the source gas to adsorb nitrogen, and supplying the product generated in the first zeolite tower to the CMS tower to perform pressurization and adsorption;
Pressurizing the first zeolite tower to adsorb nitrogen, and introducing a gas discharged from the decompressed CMS tower through the open valve into the source gas supply stage;
A fourth step of pressurizing the first zeolite tower to adsorb nitrogen, and the gas discharged under reduced pressure from the CMS tower flows into the second zeolite tower to be cleaned;
The first zeolite tower is pressurized to adsorb nitrogen, and the second zeolite tower is desorbed in vacuum, and the CMS tower is connected to the front of the compressor and decompressed to vacuum, and the high purity oxygen gas is the rear of the compressor. A fifth step of producing product gas after being stored in a storage tank connected to the storage tank;
And a sixth step of performing an equalization process after the adsorption of the first zeolite tower is completed. The method of claim 7, wherein
The control method of the high purity oxygen production apparatus, characterized in that in the first to sixth step the product of the first zeolite column is compressed and introduced into the CMS tower. The method of claim 7, wherein
The gas cleaned in the fourth step is discharged to the waste gas by the decompression means control method of the high purity oxygen production apparatus. The method of claim 7, wherein
In the first to third step, the second zeolite tower is a control method of a high purity oxygen production apparatus, characterized in that for performing a vacuum desorption process. The method of claim 7, wherein
The CMS tower is a method of controlling a high-purity oxygen production apparatus, characterized in that in the fifth step and the sixth step using a line fluidly connected to the front end of the compressor to reduce the vacuum to produce high purity oxygen. The method of claim 7, wherein
The equalizing process is a control method of a high purity oxygen production apparatus, characterized in that performed in the state that the desorption lines of the first and second zeolite tower open. 13. The method according to any one of claims 7 to 12,
Following the sixth step,
The control method of the high-purity oxygen production apparatus, characterized in that the same process is performed repeatedly by replacing the drive state of the first and second zeolite tower with each other.

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