JP2000241590A - Method and device for concentrating rare gas - Google Patents

Abstract

PROBLEM TO BE SOLVED: To downsize facilities for treating rare gases by effectively separating them from off-gases and concentrating them to reduce the volume of gases that need to be treated. SOLUTION: The air containing rare gas and the air free from the rare gas flow into the second adsorption tank 31 by way of the second pressurizing valve 46 and a pressure- equalized flow path 70 respectively to approximately equalize the pressures in adsorption tanks 30 and 31. Five seconds later, the first decompression valve 61 opens and the air rich in rare gas is sucked from the adsorption tank 30 into a recovery buffer tank 65. Meanwhile, the air containing rare gas flows into the second adsorption tank 31 by way of the pressurizing valve 46 and the internal pressure of the tank 31 gradually rises. The air containing rare gas and the air free from rare gas flow into the first adsorption tank 30 by way of the first pressurizing valve 45 and the pressure-equalized flow path 70 respectively to approximately equalize the pressures in the adsorption tanks 30 and 31. Five seconds later, the second pressure reducing valve 62 opens and the air rich in rare gas is sucked from the adsorption tank 31 into the buffer tank 65. Meanwhile, the air containing rare gas continues flowing into the adsorption tank 30 by way of the pressurizing valve 45 and the internal pressure of the tank 30 gradually rises. By repeating such a cycle, the air rich in rare gas is mixed with the air containing rare gas and is fed to the adsorption tank 30 or 31 and the air free from rare gas is discharged to the outside of a system. As a result, the rare gas in the air containing rare gas circulates through the second pump 43, the adsorption tanks and the buffer tank 65, and the gas is gradually accumulated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rare gas emission reduction adsorption treatment apparatus applicable to a boiling water light water reactor power plant.

[0002]

2. Description of the Related Art Conventionally, a boiling water type light water reactor is provided with a damping tube of a hydrogen recombination device and a rare gas hold-up device as a measure for reducing the emission of radioactive rare gas in exhaust gas. That is, in the former, an attenuating pipe is provided in an exhaust gas discharge path, and a short half-life nuclide is attenuated while the exhaust gas passes through the pipe. In the latter, exhaust gas is sufficiently attenuated by keeping the exhaust gas for a certain period of time (for example, radioactive krypton for 40 hours and radioactive xenon for 27 days).

[0003] Such measures for reduction require extensive facilities, and of course require a great deal of cost. For example, a nuclear power plant with a maximum output of 1,100 MW requires about 20 activated carbon packed towers with a capacity of more than 10 cubic meters.

[0004]

Here, if the exhaust gas emission at the above-mentioned power plant is estimated to be 50 cubic meters per hour, the annual emission will be 438,000 cubic meters. However, the amount of radioactive rare gas contained in this exhaust gas is at most about 50 cubic meters. Also,
Considering the relatively short half-life of radioactive noble gases,
It is considered that the amount of the radioactive rare gas actually requiring treatment is even smaller.

However, since there is no conventional technology for effectively separating radioactive noble gas from radioactive exhaust gas, the above-mentioned power plant emits as much as 438,000 cubic meters per year in order to treat a very small amount of radioactive noble gas as described above. At present, gas must be treated. Therefore, if the radioactive rare gas can be effectively separated from the radioactive exhaust gas, the volume of the gas that needs to be treated can be significantly reduced, and the treatment facility can be reduced in size and the treatment cost can be reduced. It becomes possible. Further, even if it is not possible to separate only the radioactive rare gas, if the rare gas containing the stable rare gas in the exhaust gas can be separated, the processing amount can be considerably reduced.

Accordingly, an object of the present invention is to reduce the volume of a rare gas treatment facility by effectively separating and concentrating a rare gas from exhaust gas and reducing the volume of gas required for treatment. .

[0007]

Means for Solving the Problems In view of the above problems, the invention according to claim 1 of the present invention provides that the rare gas-containing air is supplied to the two adsorption tanks containing the adsorbent at atmospheric pressure. Pressurized inflow at a pressure exceeding the maximum pressure to adsorb the rare gas to the adsorbent, release the pressurization to the adsorption tank, and exhaust the rare gas free air not adsorbed to the adsorbent The rare gas enrichment method is a repetition of an exhausting step and a depressurizing and desorbing step of depressurizing the adsorption tank to desorb rare gas-rich air containing the rare gas adsorbed on the adsorbent. At the same time, the rare gas-containing air is allowed to flow into one of the two adsorption tanks under pressure in the pressure adsorption stage, and the rare gas-rich air is desorbed in the other adsorption tank in the decompression desorption stage. It is to be done. Further, when the rare gas-free air is exhausted from the one adsorption tank in the exhaust stage, a part of the rare gas-free air is transferred to the other adsorption tank, and The rare gas-containing air is caused to flow under pressure into one of the adsorption tanks in the pressure adsorption stage. Further, the rare gas-rich air is desorbed from the one adsorption tank in the decompression and desorption step, and the pressurized adsorption step is continued in the other adsorption tank, and the rare gas-rich air desorbed in the decompression and desorption step is removed. A part or all of the mixture is mixed with the rare gas-containing air and then pressurized and flows into the adsorption tank again.

That is, in the method according to the present invention, the exhaust gas is krypton and xenon (hereinafter collectively referred to as “rare gas”) by the so-called pressure swing adsorption method (hereinafter referred to as “PSA method”). ) Is separated into rare gas-rich air to which rare gas is added and rare gas-free air containing no rare gas. The PSA method is a method of separating a specific component from a gas consisting of two or more components by adsorption.In addition to increasing the pressure during adsorption and lowering the pressure during desorption, this operation is performed. It means increasing the throughput of the adsorbent by repetition.

In the PSA method, if a sufficient amount of the adsorbent is present, the easily adsorbable gas is entirely adsorbed by the adsorbent when the gas is pressurized to a predetermined pressure (P1) and does not remain in the gas phase. It will be. On the other hand, even when a pressure (P2) exceeding the above P1 is applied, only a part of the poorly adsorbable gas is adsorbed, and the unadsorbed portion remains in the gas phase. Therefore, when the mixed gas is pressurized to P2 and then exhausted at a reduced pressure, only the hardly adsorbable gas is exhausted during the depressurization to P1. That is, since the easily adsorbable gas depressurized to P1 remains adsorbed, only the hardly adsorbable gas can be separated.

Further, the lower the partial pressure of the easily adsorbable gas in the mixed gas, the lower the above P1.
The pressure difference from P1 can be further increased. That is, it becomes possible to discharge more difficult-to-adsorb gas. Further, even if two kinds of gases having substantially the same adsorptivity to the adsorbent are used, if the partial pressures are different, the two gases can be separated with an appropriate pressure difference.

That is, by selecting an appropriate adsorbent and pressurizing and depressurizing conditions, rare gas-enriched air enriched with rare gas can be separated from rare gas-free air containing no rare gas. For example, as described in claim 2 described later, the adsorptivity of a rare gas to activated carbon is high for nitrogen and oxygen, which are main components of air. Further, since the partial pressure of the rare gas in the exhaust gas is extremely low, the above P1 becomes low, and the adsorption by pressurization is more effectively performed.

Further, since a part of the rare gas free air to be exhausted is transferred to the other adsorption tank, the partial pressure of the rare gas in the adsorption tank becomes lower than the partial pressure in the exhaust gas. . That is, the effect of dilution by the rare gas-free air is produced, and the partial pressure of the rare gas in the adsorption tank becomes lower than the partial pressure of the rare gas in the exhaust gas, so that the above P1 becomes lower. Therefore, adsorption by pressurization is more effectively performed.

In the present invention, by using two adsorption tanks, both stages are always performed in parallel so that one is a pressure adsorption stage and the other is a vacuum desorption stage, The inflow of the exhaust gas is always continuously performed to one of the adsorption tanks. In other words, in one adsorption tank, the pressure adsorption step, the exhaust step, and the decompression / desorption step are repeated, but in one adsorption tank, at the same time as the transition from the pressure adsorption step to the exhaust step, the other In the adsorption tank, the pressure desorption stage is shifted to the pressure adsorption stage. In addition, during the transition from the evacuation stage to the decompression / desorption stage in one adsorption tank, the pressure adsorption stage is to be continued in the other adsorption tank.

Each of the adsorption tanks is provided with a rare gas-containing air inflow path, a rare gas-free air exhaust path, and a rare gas-rich air recovery path. In addition, a transfer path through which the rare gas-free air transfers is provided between the two adsorption tanks. Next, a procedure in the rare gas enrichment method according to the present invention will be described. First, of the two adsorption tanks, one of the adsorption tanks (hereinafter referred to as tank A) is at the moment when the pressure in the tank becomes maximum in the pressure adsorption stage, and the other adsorption tank (hereinafter, referred to as tank A). The description will be started from the moment when the pressure in the tank becomes minimum in the decompression / desorption stage.

In the tank A, at the moment when the pressure in the tank is maximized, the inflow passage through which the rare gas-containing air has flowed is closed, and at the same time, the exhaust passage is opened.
Noble gas-free air is discharged. At the same time, the transfer path is also opened, so that the rare gas-free air transfers from the tank A to the tank B. That is, the process shifts to the exhaust stage.

On the other hand, in the tank B, at the moment when the pressure in the tank is minimized, the recovery path from which the rare gas-rich air has flowed out is closed, and at the same time, the inflow path is opened to open the rare gas-containing air. Comes in. At the same time,
As described above, the rare gas-free air from the tank A also moves through the transfer path. That is, the process proceeds to the pressure adsorption stage.

Thereafter, in the tank A, the discharge path and the transfer path are closed, and the discharge of the rare gas-free air is completed. At the same time, the recovery path is opened, and the rare gas-rich air starts to flow out under reduced pressure. That is, the process shifts to the vacuum desorption stage. On the other hand, in the tank B, the transfer of the rare gas-free air from the transfer passage stops, but the inflow of the rare gas-containing air from the inflow passage continues. That is, the pressure adsorption stage is continuing.

In the tank B, at the moment when the pressure in the tank becomes the maximum, the inflow passage through which the rare gas-containing air has flowed up to that time is closed, and at the same time, the exhaust passage is opened, and the rare gas is opened. Free air is exhausted. At the same time, the transfer path is also opened, so that the rare gas-free air transfers from the tank B to the tank A. That is, the process shifts to the exhaust stage.

On the other hand, in the tank A, at the moment when the pressure in the tank is minimized, the recovery passage from which the rare gas-rich air has flowed out is closed, and at the same time, the inflow passage is opened to open the rare gas-containing air. Comes in. At the same time,
As described above, the rare gas-free air from the tank B also moves through the transfer path. That is, the process proceeds to the pressure adsorption stage.

Thereafter, in the tank B, the discharge path and the transfer path are closed, and the discharge of the rare gas-free air is completed. At the same time, the recovery path is opened, and the rare gas-rich air starts flowing out due to the reduced pressure. That is, the process shifts to the vacuum desorption stage. On the other hand, in the tank A, the transfer of the rare gas-free air from the transfer passage stops, but the inflow of the rare gas-containing air from the inflow passage continues. That is, the pressure adsorption stage is continuing.

Then, the pressure in the tank A becomes maximum,
At the same time, when the pressure in the tank B is minimized, the state described first is reached again, and thereafter the above steps are repeated. That is, in the pressure adsorption stage,
In the exhaust stage where the pressure is rapidly reduced after the easily adsorbable rare gas is adsorbed by the adsorbent, rare gas free air composed of relatively hardly adsorbable nitrogen and oxygen is discharged. By appropriately adjusting the opening time of the exhaust passage at this time, the exhaust stage can be completed before the adsorbed rare gas is exhausted. Therefore, it becomes possible to discharge only the air containing no rare gas out of the exhaust gas to the outside of the system.

Further, by transferring a part of the rare gas-free air to the other adsorption tank in the exhaust stage, the rare gas-free air and the rare gas-containing air from the inflow passage are mixed in the same adsorption tank. And the partial pressure of the noble gas in the inside becomes low. Thereby, the adsorption of the rare gas in the tank is performed more effectively. Further, the rare gas-rich air desorbed under reduced pressure is mixed with the rare gas-containing air and is returned to the pressure adsorption stage, so that the rare gas can be further concentrated.

(Claim 2) The invention of claim 2 is characterized in that, in addition to the features of the invention of claim 1, the adsorbent is an adsorbent mainly composed of carbon. The carbon-based adsorbent includes, for example, activated carbon. That is, as the adsorbent, those having a larger difference in adsorbability between the rare gas and oxygen and nitrogen are suitable.

Activated carbon meets the above conditions. However, for activated carbon, nitrogen also has some adsorptive properties. However, while nitrogen has a partial pressure of about 80% in the exhaust gas, krypton and xenon are very small and have a large difference, so if an appropriate pressure difference is set, the separation of nitrogen and the rare gas can be achieved. Is quite possible.

Therefore, by using an adsorbent mainly composed of carbon such as activated carbon, it is possible to more effectively separate rare gas and air. (Claim 3) The invention according to claim 3 is characterized in that noble gas-containing air is pressurized into the two adsorption tanks containing the adsorbent and the adsorption tank at a pressure exceeding atmospheric pressure, and the rare gas is introduced into the adsorbent. Pressurizing means for adsorbing the rare gas-free air; releasing means for releasing the pressure on the adsorption tank to exhaust the rare gas-free air not adsorbed to the adsorbent; and the rare gas-free air between the two adsorption tanks. A rare gas concentrating device having a pressure equalizing means for transferring a part of the gas and a pressure reducing means for depressurizing the adsorption tank and desorbing the rare gas rich air containing the rare gas adsorbed on the adsorbent. Then, when the pressurizing means causes the rare gas-containing air to flow into one of the two adsorption tanks under pressure, the other adsorption tank is depressurized to desorb rare gas-rich air. The decompression means is formed in. In addition, the exhaust means exhausts the rare gas-free air from the one adsorption tank, and the equalizing means transfers a part of the rare gas-free air to the other adsorption tank. The pressurizing means is formed so that the rare gas-containing air flows into the other adsorption tank by pressurization. Further, when the decompression means desorbs rare gas-rich air from the one adsorption tank, a part or all of the rare gas-rich air desorbed by the decompression means to the other adsorption tank, The above-mentioned pressurizing means is formed so as to be mixed with the rare gas-containing air and flow under pressure.

The "pressurizing means" includes an air supply device such as a pressure pump capable of forcibly sending air containing a rare gas to be treated into the adsorption tank, and an air supply device from this air supply device to both the adsorption tanks. And a valve for switching the flow path. That is, in the invention according to the present claim, two adsorption tanks are provided, but by switching this valve,
It is possible to feed the rare gas-containing air into one of the adsorption tanks.

The "exhaust means" includes a valve capable of opening and closing an exhaust path between each adsorption tank and the outside. This valve may be formed to open when the internal pressure of the adsorption tank reaches a predetermined value. Further, a valve that opens when the pressure difference between the adsorption tank and the outside reaches a predetermined value may be provided. The “equalizing means” includes a flow path that connects the two adsorption tanks, and a valve provided in the flow path.
The valve is opened at the same time as the valve of the exhaust means is opened.

The "decompression means" includes an exhaust device such as a decompression pump and a valve for switching a flow path from both adsorption tanks to the exhaust device. That is, by adjusting the opening and closing of the valve, the rare gas-rich air is desorbed from one of the two adsorption tanks. In addition, part or all of the rare gas-rich air desorbed by the decompression means is sent again to the above-mentioned pressurization means, and is again adsorbed to the adsorption tank.

That is, the "pressurizing adsorption step" in the description of the first aspect is performed by the pressurizing means. Similarly, the “exhaust step” is performed by the exhaust means and the pressure equalizing means, and the “decompression / desorption step” is performed by the depressurizing means. (Claim 4) The invention according to claim 4 is characterized in that, in addition to the features of the invention described in claim 3, the pressure equalizing means includes (a) two branch flow paths which branch in parallel, and (b) one branch flow. Two one-way valves arranged with the outflow side facing the channel, (c) to the other branch flow path,
(D) two one-way valves arranged with the inflow sides facing each other
(B) a one-way flow path connecting between the one-way valves and (c) the one-way valve, and (e) an additional device having a flow control device provided in the middle of (d). It is characterized by.

In the present invention, rare gas-free air is alternately discharged from both adsorption tanks when viewed in a time series. At the same time as this discharge, the rare gas-free air moves from one adsorption tank to the other. Therefore, in this transition, the direction in which the rare gas-free air flows through the equalizing means is reversed at regular time intervals.

On the other hand, in the present invention, if the equalizing means can control the flow rate of the rare gas free air moving between the adsorption tanks, the amount of the rare gas free air exhausted from the adsorption tank can be increased. It becomes possible. However, it is usually difficult to provide a means for adjusting the flow rate in a flow in which the direction is reversed as described above.

Therefore, in order to provide a means for adjusting the flow rate in the equalizing means, a one-way flow path is formed as described above. In this way, the flow always flows in one direction from (b) to (c), regardless of which one of the adsorption tanks flows in the one-way flow path. For convenience of explanation, one of the two adsorption tanks is referred to as a tank A and the other is referred to as a tank B, and among the pressure equalizing means connecting the two, the flow path corresponding to the branch flow path of (b) above Is referred to as a flow path 1, and the flow path 2 is referred to as a flow path 2. Further, of the two one-way valves in the flow path 1, the one located on the tank A side is called a valve 1A, and the one located on the tank B side is called a valve 1B. Similarly, among the two one-way valves in the flow path 2, the valve 2A, which is located on the tank A side,
The one located on the tank B side is called a valve 2B. Here, the one-way valve refers to a valve through which gas can pass only in one direction.
That is, only the air flowing from the tank A and the tank B can pass through the valve 1A and the valve 1B, respectively. Further, only the air flowing to the tank A and the tank B can pass through the valve 2A and the valve 2B, respectively.

In the case of the transfer from the tank A to the tank B, the rare gas-free air from the tank A to the pressure equalizing means is once divided into the flow path 1 and the flow path 2.
However, since the air cannot pass through the valve 2A in the flow path 2, the air eventually passes through the valve 1A in the flow path 1. Since the air cannot pass through the valve 2A of the flow path 1, the air passes through the one-way flow path (d) and reaches the flow path 2.

Here, the air cannot pass through the valve 2A. Because the end of valve 2A is tank A,
This is because the pressure on the tank A side is high.
Therefore, the air passes through the valve 2B and reaches the tank B having a lower pressure. On the other hand, in the case of the transfer from the tank B to the tank A, on the contrary, the rare gas-free air from the tank B passes through the one-way flow path (d) from the valve 1B and passes through the valve 2A. This leads to tank A.

That is, in either case, the flow direction of the one-way flow path (d) is always from the flow path 1 to the flow path 2. Therefore, it is possible to provide a flow control device such as a flow control valve in the one-way flow path,
This makes it possible to adjust the flow rate of the rare gas-free air that moves between the adsorption tanks.

(Claim 5) The invention according to claim 5 is characterized in that, in addition to the constitution of the invention according to claim 3 or 4, the two auxiliary adsorption tanks containing an adsorbent and the auxiliary adsorption tank are desorbed by decompression means. Auxiliary pressurizing means for allowing the rare gas-rich air to flow under pressure at a pressure exceeding the atmospheric pressure to adsorb the rare gas to the adsorbent, releasing the pressurization to the auxiliary adsorption tank, and adsorbing the adsorbent Auxiliary exhaust means for exhausting the rare gas free air that has not been produced, auxiliary equalizing means for transferring a part of the rare gas free air between the two auxiliary adsorption tanks, and depressurization of the auxiliary adsorption tank to perform the adsorption An auxiliary pressure reducing means for desorbing the rare gas rich air containing the rare gas adsorbed on the agent and transferring a part or all of the air to the pressurizing means is provided. Then, when the auxiliary pressurizing means pressurizes and flows the rare gas-rich air into one of the two auxiliary adsorption tanks,
The auxiliary pressure reducing means is formed so as to depressurize the other auxiliary adsorption tank, desorb rare gas rich air, and transfer part or all of the air to the pressure means. Further, the auxiliary exhaust means is provided from the one auxiliary suction tank,
At the same time as exhausting the rare gas-free air, the auxiliary equalizing means shifts a part of the rare gas-free air to the other auxiliary adsorption tank, The auxiliary pressurizing means is formed so that the rare gas-rich air flows under pressure. Further, when the auxiliary pressure reducing means desorbs the rare gas-rich air from the one auxiliary adsorption tank and transfers a part or all of the air to the pressurizing means, the auxiliary pressure reducing means sends the pressure reducing means to the other adsorption tank. The auxiliary pressurizing means is formed so that the rare gas-rich air desorbed by the above is pressurized and flown.

That is, the same rare gas concentrating device is connected in two stages, and the rare gas is further concentrated in the second stage. By doing so, the rare gas-rich air decompressed and desorbed by the first-stage decompression means is again concentrated by the PSA method in the auxiliary adsorption tank, whereby the rare gas concentration in the rare gas-rich air decompressed and desorbed by the auxiliary decompression means is reduced. It is possible to further increase. This rare gas-rich air may be sent again to the first-stage pressurizing means to further concentrate the rare gas concentration. Further, as in the invention described in claim 6 below, the rare gas-rich air further concentrated in the second stage may be taken out of the system and may be sufficiently attenuated by storage for a certain period of time before being discharged. in this case,
It is possible to further reduce the volume of gas to be stored.

(Claim 6) In the invention according to claim 6, in addition to the features of the invention described in claim 5, a bypass flow path is provided in the auxiliary pressure reducing means, and rare gas-rich air is supplied from the bypass flow path to the outside of the system. It is characterized by being removable. That is, in the invention according to the fifth aspect, since it is further concentrated in the second stage, it can be taken out of the system from here via the bypass route and subjected to processing.

As an example of the treatment, the radioactivity may be attenuated by storing the gas enriched with the rare gas for a predetermined period of time. Here, the volume of the gas to be stored can be remarkably reduced as compared with the initial exhaust gas amount, so that the processing facility can be reduced. (Claim 7) The invention according to claim 7 is based on claims 3, 4, 5
Or, in addition to the features of the invention described in 6, the adsorption tank has a short diameter and a long length, and the equalizing means connects the upper parts of the two adsorption tanks, and the inflow path of the rare gas-containing air and the pressure reduction by the pressurizing means. The outflow path of the rare gas-rich air by the means is provided at the lower part of the adsorption tank, and the exhaust path of the rare gas-free air by the exhaust means is provided at the upper part of the adsorption tank.

The rare gas-containing air flows in from the lower part of the adsorption tank, is adsorbed in the tank, reaches the upper part of the tank, and is exhausted. At this time, if the capacity of the adsorption tank is the same, the longer the flow path in the tank, the greater the chance of being adsorbed by the adsorbent. Therefore, as in the invention described in the present invention, by making the adsorption tank short and long, the adsorption of the rare gas in the adsorption tank is made more effective.

Further, the rare gas free air flowing from another adsorption tank flows from the upper part of the adsorption tank, so that the rare gas concentration in the upper part of the adsorption tank can be further reduced. By performing the exhaust by the exhaust means from the upper part of the adsorption tank, the gas located at the upper part where the rare gas concentration is low is preferentially exhausted. (Claim 8) The invention according to claim 8 is based on claims 3, 4,
In addition to the features of the invention described in 5, 6, or 7, the adsorbent is a carbon-based adsorbent.

That is, the claimed invention has the same meaning as the claimed invention.

[0043]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments and examples of the present invention will be described with reference to the drawings and tables. In the following description, krypton and xenon used in the experiment are in a stable state, that is, non-radioactive. (Study of Adsorbent) Prior to studying the embodiment of the rare gas concentrator 10 according to the present invention, first, an adsorbent was studied.

In the present invention, the adsorbent is krypton and xenon contained in air (hereinafter collectively referred to as "rare gas").
Called. ). Therefore, the higher the adsorbability of the rare gas with respect to nitrogen and oxygen, which are the main components of air, the more desirable as the adsorbent. And from the experiment of the separation ability by gas chromatography, molecular sieve (Molecular sieve 5A) and activated carbon were candidates for the adsorbent. Using these two, the adsorption property of each component gas was examined.

That is, an adsorption tank having a known volume is filled with a test gas to a pressure of 1 atm. Then, an adsorbent is charged into the adsorption tank, and after a certain period of time, the pressure drop in the adsorption tank is measured. The results are shown in Table 1 below.

[0046]

[Table 1]

That is, in any of the gases, activated carbon has a higher adsorptivity. Here, in the adsorbent used in the present invention, it is desirable that the adsorption characteristics of nitrogen and krypton differ greatly. Looking at the results in Table 1 above, the amount of krypton adsorbed on nitrogen is 1.47 times (0.87 / 0.59) for molecular sieves, but 2.97 times (24.76 / 8.35) for activated carbon.
It has been found that activated carbon is more desirable as the adsorbent used in the present invention. Therefore, in the following embodiments, activated carbon is used as the adsorbent.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. The experimental data referred to below is for krypton only. Since xenon has a much higher adsorptivity to activated carbon than krypton, and has a much lower abundance in the air, xenon is naturally adsorbed at least under conditions where krypton is adsorbed. The experimental data is omitted.

(First Embodiment) (Structure) FIG. 1 schematically shows a first embodiment of the present invention. Noble gas concentrator 10 according to the present embodiment
Are two adsorption tanks containing adsorbents, an inflow passage 40 into which air containing a rare gas (hereinafter referred to as “air containing rare gas”) flows into these adsorption tanks, and these adsorption tanks , An exhaust passage 50 from which air containing no rare gas (hereinafter referred to as “rare gas free air”) is discharged.
Equalizing flow passage 70 through which rare gas-free air transfers between these adsorption tanks, and a recovery flow from which air with an increased concentration of rare gas (hereinafter referred to as “rare gas-rich air”) is recovered from these adsorption tanks. Road 60 is to be provided.

The two adsorption tanks have exactly the same structure. That is, it has a cylindrical shape with an inner diameter of 107 mm and a length of 628 mm, and is filled with 2.7 kg of activated carbon.
Here, one of them is referred to as a first adsorption tank 30, and the other is referred to as a second adsorption tank 31. Noble gas-containing air is fed into the adsorption tank through the inflow channel 40. Then, when pressurized at a pressure exceeding atmospheric pressure, the rare gas is adsorbed by the adsorbent, and only nitrogen and oxygen remain in the gas phase.

Here, when the pressure of the adsorption tank is reduced, before the adsorbed rare gas is desorbed, residual rare gas-free air containing nitrogen and oxygen as main components is discharged from the adsorption tank to the exhaust passage.
Exhausted through 50. Further, when the pressure of the adsorption tank is reduced to near the atmospheric pressure, the adsorbed rare gas is desorbed and the adsorbent is regenerated. The rare gas-rich air containing the desorbed rare gas has a higher rare gas concentration than the original rare gas-containing air.

Then, the rare gas rich air is supplied to the recovery passage.
After being recovered through 60 and the adsorbent has been regenerated, the rare gas-containing air is again sent in through the inflow passage 40 and pressurized. Hereinafter, a more detailed structure will be described for each channel. (Inflow Channel) The inflow channel 40 is provided with two pumps for sending gas to these adsorption tanks.

One is a first pump 41 for feeding rare gas-containing air. The rare gas-containing air is regarded as exhaust gas generated in an actual power plant, and is a mixture of air and krypton so as to have a predetermined concentration. Here, the stable krypton concentration in the actual exhaust gas is about 10 ^-4 % by volume, but in consideration of the detection capability, the concentration was set to be much higher than the actual one (described later). Xenon is not mixed for the above reason.

Another pump is a second pump that causes a mixed gas of rare gas-containing air sent by the first pump 41 and a rare gas-rich air described later to flow into the first adsorption tank 30 and the second adsorption tank 31. Two pumps 43. Further, between the first pump 41 and the second pump 43, an inflow flow rate regulating valve
42 is provided so that the inflow speed of the rare gas-containing air can be adjusted.

Now, the flow path from the second pump 43 to the adsorption tank branches in the middle into two, one reaching the first adsorption tank 30 and the other reaching the second adsorption tank 31.
In the middle of each of them, a valve that can be opened and closed electromagnetically is provided. Here, what is provided in the flow path to the first adsorption tank 30 is the first pressure valve 45, and the second adsorption tank 31
The components provided in the flow path to the second pressure are referred to as second pressurizing valves 46, respectively. These first pressure valve 45 and second pressure valve
In 46, when one is open, the other is closed, and the mixed gas always flows into one of the adsorption tanks. Furthermore, the second pump 43
An inflow sample cock 44 is provided between the inlet and the above-mentioned branch point, from which a sample gas can be appropriately collected.

(Exhaust Channel) The rare gas-free air exhausted from the first adsorption tank 30 and the second adsorption tank 31 is temporarily stored in the exhaust buffer tank 53 provided in the exhaust channel 50. A first exhaust valve 51 is provided in a flow path from the first adsorption tank 30 to the exhaust buffer tank 53, and a second exhaust valve 52 is provided in a flow path from the second adsorption tank 31 to the exhaust buffer tank 53. ing. These valves are one-way valves that open when the pressure difference between the adsorption tank and the exhaust buffer tank 53 reaches a predetermined value. Further, the exhaust buffer tank 53 is provided with a pressure control valve 54 so that a predetermined internal pressure can be maintained.

Further, an exhaust flow rate control valve 55 is provided in a flow passage through which the rare gas free air is exhausted from the exhaust buffer tank 53, so that the exhaust speed of the rare gas free air can be adjusted. In addition, an exhaust sample cock 56 is provided in this flow channel, from which a sample gas can be appropriately collected. (Recovery Channel) On the other hand, the rare gas-rich air containing the rare gas adsorbed by the adsorbent in the adsorption tank is sucked by the reduced pressure and reaches the recovery buffer tank 65 provided in the recovery channel 60. The recovery buffer tank 65 is connected to the second pump 43, and a negative pressure is generated by the operation of the second pump 43, so that rare gas-rich air is sucked from the adsorption tank. The first pressure reducing valve 61 is provided in the flow path from the first adsorption tank 30 to the recovery buffer tank 65, and the recovery buffer tank
The second pressure reducing valve 62 is provided in each of the channels up to 65. Either of these valves can be opened and closed electromagnetically. That is, when one of the valves is open, the other is closed.

As described above, the recovery flow channel 60 from the recovery buffer tank 65 joins the inflow flow channel 40 between the first pump 41 and the second pump 43 so that the first pump Noble gas-containing air from 41 and recovery buffer tank
Noble gas rich air from 65 is mixed and the second pump 43
It is supposed to flow to. (Equalizing flow path) In addition, the first adsorption tank 30 and the second adsorption tank 31 are connected by an equalizing flow path 70 having two equalizing valves that can be electromagnetically opened and closed. Here, the first adsorption tank 30 side is referred to as a first equalizing valve 71, and the second adsorption tank 31 side is referred to as a second equalizing valve 72. Then, the first equalizing valve 71 and the second equalizing valve 72 open and close in synchronization. The first equalizing valve 71 and the second equalizing valve 72
In order to adjust the flow rate of the gas passing through the pressure equalizing flow path 70, an additional device 80 described below is provided.

First, the equalizing flow path 70 branches in parallel between the first equalizing valve 71 and the second equalizing valve 72. One is referred to as a first branch 81, and the other is referred to as a second branch 84. On the first adsorption tank 30 side of the first branch 81, a one-way valve from the first adsorption tank 30 to the second adsorption tank 31 is provided. Similarly, on the second adsorption tank 31 side of the first branch 81,
A one-way valve from the second adsorption tank 31 to the first adsorption tank 30 is provided. Here, the former valve is replaced with a first equalizing inflow valve 82
, And the latter valve is referred to as a second equalizing inflow valve 83. That is, the first equalizing inflow valve 82 and the second equalizing inflow valve 83
Means that the respective outflow sides face each other.

On the other hand, on the first adsorption tank 30 side of the second branch 84, a one-way valve from the second adsorption tank 31 to the first adsorption tank 30 is provided. Similarly, on the second adsorption tank 31 side of the second branch 84, the second adsorption tank 31
A one-way valve is provided. Here, the former valve is referred to as a first equalizing outflow valve 85, and the latter valve is referred to as a second equalizing outflow valve 86. That is, the first equalizing pressure outflow valve 85 and the second equalizing pressure outflow valve 86 are located with their respective inflow sides facing each other.

Then, between the first equalizing inflow valve 82 and the second equalizing inflow valve 83 in the first branch 81, and between the first equalizing outflow valve 85 and the second equalizing outflow valve 86 in the second branch 84. A one-way channel 87 is connected between the two. Further, in this one-way flow path 87, a pressure equalizing pump 88 for adjusting the flow rate,
An equalizing flow control valve 89 is provided. Here, when the gas flows from the first adsorption tank 30 to the second adsorption tank 31, the gas cannot pass through the first equalizing pressure outflow valve 85 of the second branch 84, and the first It passes through a pressure equalizing inflow valve 82. Since the gas cannot pass through the second equalizing pressure inflow valve 83, the gas reaches the second branch 84 via the one-way flow path 87. And
In this case, since the pressure on the first adsorption tank 30 side is high, the same gas does not pass through the first
After passing through 86, it reaches the second adsorption tank 31.

That is, when gas flows from the first adsorption tank 30 to the second adsorption tank 31,
From, passing through the one-way flow path 87 via the first equalizing pressure inflow valve 82,
Subsequently, it reaches the second adsorption tank 31 through the second equalizing pressure outflow valve 86. Similarly, when gas flows from the second adsorption tank 31 to the first adsorption tank 30, the gas passes from the second adsorption tank 31 through the one-way flow path 87 via the second equalizing pressure inflow valve 83, and subsequently The gas reaches the first adsorption tank 30 via the first pressure equalizing outflow valve 85.

Therefore, no matter what direction the gas flows, in the one-way channel 87, the gas always flows from the first branch 81 to the second branch 84. (Pressure graph) Next, the pressure fluctuation in the adsorption tank is shown in FIG.
This will be described with reference to an example. FIG. 2 is a graph showing the pressure fluctuation in the adsorption tank by gauge pressure, wherein a solid line indicates the first adsorption tank 30 and a broken line indicates the second adsorption tank 31.

First, in one adsorption tank, the cycle of pressurizing for 30 seconds, the step of exhausting for 5 seconds, and the step of desorbing for 25 seconds are defined as one cycle, and this cycle is repeated. That is, the pressure in the adsorption tank gradually increases during the pressurization stage, but is reduced to the balance pressure with the other adsorption tank in the exhaust stage. Then, during the desorption stage, the pressure inside the adsorption tank becomes approximately atmospheric pressure.

The following cycle is repeated between the two adsorption tanks. First, at the same time as the second adsorption tank 31 enters the pressurization stage, the first adsorption tank 30 enters the exhaust stage. This is the stage indicated by A in FIG. Five seconds later, the first adsorption tank 30 enters the desorption stage, while the second adsorption tank 31 remains in the pressurization stage. This corresponds to B in FIG.
This is the stage shown in FIG.

It means that 25 seconds have elapsed since the first adsorption tank 30 entered the desorption stage, and 30 seconds have elapsed since the second adsorption tank 31 entered the pressurization stage. Therefore, this time, the first adsorption tank 30 enters the pressurization stage, and at the same time, the second adsorption tank 31 enters the exhaust stage. This is the stage indicated by C in FIG. Five seconds later, the second adsorption tank 31 enters the desorption stage, while the first adsorption tank 30 remains in the pressurization stage. This is the stage indicated by D in FIG.

Then, 25 seconds have elapsed since the second adsorption tank 31 entered the desorption stage, and 30 seconds have elapsed since the first adsorption tank 30 entered the pressurization stage. Therefore, again, the second adsorption tank 31 enters the pressurization stage, and at the same time, the first adsorption tank 30 enters the exhaust stage. This is the stage indicated by A in FIG. That is, returning to the initial state,
This cycle will be repeated.

Next, the change of the pressure in FIG. 2 due to the gas flow in FIG. 1 and the opening and closing of each valve shown in FIG. 3 will be described. FIG. 3 is a time chart showing the opening and closing of each valve. The hatched column indicates that the corresponding valve is open. The time shown in FIG. 3 corresponds to the time shown in FIG. First, up to the stage A in FIG. 2, that is, at the stage D in FIG. 2, the first pressurizing valve 45 is open, while the second pressurizing valve 46 is closed.
Therefore, since the rare gas-containing air is sent into the first adsorption tank 30, the pressure in the first adsorption tank 30 gradually increases. At the same time, the second pressure reducing valve 62 opens, while
The first pressure reducing valve 61 is closed. Therefore, since the rare gas rich air is sucked into the recovery buffer tank 65,
The pressure in the second adsorption tank 31 gradually decreases. Since the pressure in the first adsorption tank 30 has not reached the maximum yet, and the pressure in the second adsorption tank 31 is lower than the atmospheric pressure, the first exhaust valve 51 and the second exhaust valve 52 Are both closed. Further, the first equalizing valve 71 and the second equalizing valve 72 are also closed.

Then, at the moment when the pressure in the first adsorption tank 30 becomes maximum and the pressure in the second adsorption tank 31 becomes minimum, that is, at the time of 0 second on the time axis in FIG. ,
At the same time that the first pressure valve 45 is closed, the second pressure valve 46 is opened, and pressurization of the second adsorption tank 31 is started. on the other hand,
When the pressure in the first adsorption tank 30 becomes maximum, the pressure difference between the first adsorption tank 30 and the exhaust buffer tank 53 reaches a predetermined value, the first exhaust valve 51 is opened, and the rare gas-free air is discharged into the exhaust buffer tank. Exhausted to 53. However, when the pressure in the first adsorption tank 30 decreases due to the exhaust, the first exhaust valve
51 closes and exhaust stops.

At the same time when the first exhaust valve 51 is opened, the first equalizing valve 71 and the second equalizing valve 72 are opened, and the rare gas-free air is discharged from the first adsorption tank 30 through the equalizing passage 70. Transfer to the two adsorption tanks 31 begins. That is, the second adsorption tank
The rare gas-containing air that has passed through the second pressurizing valve 46 and the rare gas-free air that has passed through the equalizing flow path 70 flow into the 31. Thereby, the first adsorption tank 30 and the second adsorption tank
31 becomes almost equal pressure. This is the stage indicated by A in FIG.

Then, when the first adsorption tank 30 and the second adsorption tank 31 become substantially equal in pressure, that is, the first pressure equalizing valve 71
After a lapse of 5 seconds from the opening of the second equalizing valve 72, both valves are closed. At the same time, the first pressure reducing valve 61 is opened, and the rare gas-rich air is sucked from the first adsorption tank 30 into the recovery buffer tank 65. On the other hand, in the second adsorption tank 31, the inflow of the rare gas-containing air continues through the second pressure valve 46, and the internal pressure gradually increases. This is the stage indicated by B in FIG.

Then, at the moment when the pressure in the second adsorption tank 31 becomes maximum and the pressure in the first adsorption tank 30 becomes minimum, that is, at the time point of 30 seconds on the time axis in FIG. ,
Simultaneously with the closing of the second pressurizing valve 46, the first pressurizing valve 45 opens and the pressurization of the first adsorption tank 30 is started. on the other hand,
When the pressure in the second adsorption tank 31 reaches a maximum, the pressure difference between the second adsorption tank 31 and the exhaust buffer tank 53 reaches a predetermined value, the second exhaust valve 52 is opened, and the rare gas free air is exhausted into the exhaust buffer tank. Exhausted to 53. However, when the pressure in the second adsorption tank 31 decreases due to the exhaust, the second exhaust valve
52 closes and exhaust stops.

At the same time when the second exhaust valve 52 is opened, the first pressure equalizing valve 71 and the second pressure equalizing valve 72 are opened, and the rare gas free air is discharged from the second adsorption tank 31 through the pressure equalizing flow path 70. Transfer to one adsorption tank 30 starts. That is, the first adsorption tank
The rare gas-containing air that has passed through the first pressurizing valve 45 and the rare gas-free air that has passed through the equalizing flow path 70 flow into 30. Thereby, the first adsorption tank 30 and the second adsorption tank
31 becomes almost equal pressure. This is the stage indicated by C in FIG.

Then, when the first adsorption tank 30 and the second adsorption tank 31 become substantially equal in pressure, that is, the first pressure equalizing valve 71
5 seconds after the second equalizing valve 72 is opened (35 seconds on the time axis in FIG. 2), both valves are closed. At the same time, the second pressure reducing valve 62 is opened, and the rare gas-rich air is sucked from the second adsorption tank 31 into the recovery buffer tank 65. On the other hand, in the first adsorption tank 30, the flow of the rare gas-containing air continues through the first pressurizing valve 45, and the internal pressure gradually increases. This is the stage indicated by D in FIG.

Thereafter, the above steps A to D are repeated. Then, the rare gas-rich air collected in the collection buffer tank 65 is, by the second pump 43,
The mixture is mixed with the rare gas-containing air and sent to the first adsorption tank 30 or the second adsorption tank 31 again. Also,
The rare gas-containing air sent by the first pump 41 is simultaneously supplied with the rare gas-containing air by the first pump 41, and the rare gas-free air is discharged from the exhaust buffer tank 53 to the outside of the system at the same time. Are circulated through the second pump 43, the adsorption tank and the recovery buffer tank 65, and are gradually accumulated.

(Example) Hereinafter, an example of the present embodiment will be described. First, the inflow amount of the first pump 41 and the discharge amount from the exhaust buffer tank 53 were matched by the inflow flow control valve 42 and the exhaust flow control valve 55, respectively. The inflow of rare gas-containing air was 5, 10 and 20 liters per minute.
The rare gas-containing air contains 2% of krypton. The flow rate of the second pump 43 was set to 80 liters per minute.

Then, after preliminarily operating with air containing no rare gas and confirming stable operation, air containing rare gas was flowed. Sample gas was sampled from the inflow sample cock 44 and the exhaust sample cock 56 as needed, and measured by gas chromatography. In the former sample, the state of accumulation of the rare gas by circulating through the adsorption tank is shown. In the latter sample, the krypton concentration in the exhaust gas is indicated.

FIG. 4 is a graph showing the results. After the noble gas-containing air has flowed in,
The flow rate was increased to 10 liters / minute and then to 20 liters / minute. At a flow rate of 5 liters / minute, noble gas was not detected in the exhaust gas (solid line). Moreover, in the inflow sample (broken line), it can be seen that the rare gas is concentrated almost linearly.

However, at an inflow rate of 10 liters / min or more, noble gas is discharged into the exhaust gas, and no enrichment by circulation is observed. In particular, at an inflow rate of 20 liters / minute, the inflowing rare gas is directly discharged into the exhaust gas. Therefore, it has been recognized that if appropriate conditions are selected, it becomes possible to concentrate the rare gas by circulation without including the rare gas in the exhaust gas.

(Second Embodiment) Next, in the second embodiment, the exhaust position from the adsorption tank was examined. That is, optimization of the positions of the exhaust passage 50 and the equalizing passage 70 with respect to the adsorption tank was attempted. The outline is shown in FIG.

(1) in FIG. 5 shows that the exhaust flow path 50 and the equalizing flow path 70 are connected to an adsorption tank (hereinafter referred to as a “standard adsorption tank”) having an inside diameter of 107 mm and a length of 700 mm and containing 2.7 kg of activated carbon. (2) in FIG. 5 is a reference adsorption tank.
Above 100, an adsorption tank (1.3 mm in diameter, 600 mm in length, containing 1.3 kg of activated carbon)
And ) Are connected to each other, and an exhaust passage 50 and a pressure equalizing passage 70 are provided above the additional adsorption tank 101.

(3) in FIG. 5 connects the additional adsorption tank 101 to the upper part of the reference adsorption tank 100, and provides an exhaust passage 50 between the two. It is provided in. (4) in FIG. 5 connects the additional adsorption tank 101 to the upper part of the reference adsorption tank 100, provides a pressure equalizing flow path 70 between the two, and the exhaust flow path 50
It is provided on the upper part of 101.

(5) in FIG. 5 shows that the additional adsorption tank 101 is connected in parallel with the reference adsorption tank 100, and the exhaust passage 50 and the pressure equalizing passage 70 are provided above these. And
In any case shown in FIG. 5, the rare gas-containing air is allowed to flow from the lower part of the reference adsorption tank 100. (Example) For each of the above arrangements, krypton concentration of 1%
Was flowed in, and the concentration of krypton in the exhaust gas was measured by gas chromatography.

FIG. 6 is a graph showing the result. According to this, for (1) and (3),
In (2) and (4), the krypton concentration in the exhaust gas could be further reduced. However, although it is considered that this result is due to the increase in the amount of adsorbent, it is similarly effective for the parallel (5). Therefore, when the amount of adsorbent in the adsorption tank is the same, It was presumed that the longer the adsorption tank was, the more the rare gas concentration in the exhaust gas could be reduced.

(Third Embodiment) (Structure) In the rare gas concentrator 10 according to the third embodiment, the recovery flow channel 60 of the rare gas concentrator 10 shown in the first embodiment is The structure is such that an auxiliary rare gas concentrator (hereinafter referred to as “auxiliary device”) is provided. That is,
The rare gas-rich air obtained by the rare gas concentrating device (hereinafter, referred to as “first-stage device”) described in the first embodiment is further concentrated by the auxiliary device 120. FIG. 7 shows the outline. That is, in addition to the structure in the first embodiment, the following structure is provided. In the structure of the present embodiment, portions common to the first embodiment are given the same names and reference numerals, and description thereof is omitted below.

The auxiliary device 120 includes two auxiliary adsorption tanks for storing adsorbents, an auxiliary inflow passage 140 through which rare gas-containing air flows into these auxiliary adsorption tanks, and a rare gas from these auxiliary adsorption tanks. Auxiliary exhaust passage 150 for discharging gas-free air, auxiliary equalizing passage 170 for transferring rare gas-free air between these auxiliary adsorption tanks, and auxiliary recovery flow for collecting rare gas-rich air from these auxiliary adsorption tanks Road 160 is to be provided.

The auxiliary inflow passage 140 is provided with an auxiliary pump 143 corresponding to the second pump 43 in the inflow passage 40 of the first stage device 20. Further, a first auxiliary pressurizing valve 145 and a second auxiliary pressurizing valve 146 corresponding to the first pressurizing valve 45 and the second pressurizing valve 46 in the inflow passage 40 of the first stage device 20, respectively.
Is also provided. Further, in the auxiliary exhaust passage 150, a first auxiliary exhaust valve 151 and a second auxiliary exhaust valve 152 corresponding to the first exhaust valve 51 and the second exhaust valve 52 in the exhaust passage 50 of the first stage device 20, respectively, An auxiliary exhaust buffer tank 153 corresponding to the exhaust buffer tank 53 and an auxiliary pressure control valve 154 corresponding to the pressure control valve 54 are provided.

Further, the first-stage device 2
The first equalizing valve 71 and the second equalizing valve 72 in the zero equalizing flow path 70
Are provided with a first auxiliary equalizing valve 171 and a second auxiliary equalizing valve 172, respectively. However, the additional device 80 provided in the pressure equalizing channel 70 is not provided. In addition, the auxiliary recovery channel 160 includes the recovery channel 60 of the first-stage apparatus 20.
A first auxiliary pressure reducing valve 161 and a second auxiliary pressure reducing valve 162 corresponding to the first pressure reducing valve 61 and the second pressure reducing valve 62, respectively, and an auxiliary recovery buffer tank 165 corresponding to the recovery buffer tank 65 are provided. Further, a bypass channel 163 is provided between the first auxiliary pressure reducing valve 161 and the second auxiliary pressure reducing valve 162 and the auxiliary recovery buffer tank 165, and a rare gas trap capable of containing rare gas rich air is provided here. 164 are provided.

Further, the auxiliary recovery buffer tank 165
Communicates with the first auxiliary adsorption tank 130 and the second auxiliary adsorption tank 131 via the auxiliary inflow channel 140. In addition, the auxiliary recovery buffer tank 165 is also located between the first pressure reducing valve 61 and the second pressure reducing valve 62 and the recovery buffer tank 65 in the recovery channel 60 of the first-stage device 20. .

That is, the rare gas-rich air obtained by the first stage device 20 is temporarily stored in the auxiliary recovery buffer tank 165 by suction of the auxiliary pump 143. A part of the rare gas-rich air will again reach the first stage device 20 by the suction of the second pump 43, but another part will pass through the auxiliary inflow passage 140 to the first auxiliary adsorption tank. It flows into 130 or the second auxiliary adsorption tank 131. Then, the rare gas-free air not adsorbed by the adsorbent is exhausted through the auxiliary exhaust passage 150, and part of the air is transferred between the auxiliary adsorption tanks through the auxiliary equalizing passage 170.

On the other hand, the rare gas-rich air containing the rare gas adsorbed by the adsorbent further increases the rare gas concentration as compared with the time when it flows into the auxiliary device 120. Then, it is collected in the auxiliary collection buffer tank 165. The rare gas-rich air collected in the auxiliary recovery buffer tank 165 is mixed with the rare gas-rich air sucked from the first-stage device 20 as described above. Then, a part thereof will reach the first stage device 20 by suction of the second pump 43, but another part will pass through the auxiliary inflow passage 140, and the first auxiliary adsorption tank 130 or the second It will flow into the secondary auxiliary adsorption tank 131 again.

In this way, the rare gas in the exhaust gas is gradually concentrated while circulating through the first stage device 20 and the auxiliary device 120. Then, when the concentration reaches an appropriate concentration, it can be taken out from the rare gas trap 164 in the bypass channel 163 and subjected to predetermined processing. The predetermined process includes, for example, a process of attenuating radioactivity by storing the radioactivity for a certain period of time. Even in this case, the volume of gas to be stored can be significantly reduced in view of the amount of exhaust gas generated by power generation.

In the present embodiment, the shape of the suction tank is made short and long from the study in the second embodiment. Specifically, the shape was as shown in FIG.
That is, the adsorption tank of the first stage device 20 (the first adsorption tank
30 and the second adsorption tank 31) were formed in an inverted U-shape in which the upper parts of two cylinders having an inner diameter of 44 mm and a length of 1765 mm were connected. And
The interior is filled with 2.9 kg of activated carbon. In the adsorption tank of the first-stage apparatus 20, an inflow channel 40 and a recovery channel 60 are provided at two lower portions of the tank, and an exhaust channel 50 and a pressure equalizing channel 70 are provided at an upper connecting portion. It is supposed to be.

On the other hand, the suction tanks of the auxiliary device 120 (the first auxiliary suction tank 130 and the second auxiliary suction tank 131) are
It was U-shaped, connecting the lower parts of two cylinders having a length of 44 mm and a length of 865 mm. The interior is filled with 1.35 kg of activated carbon. In the suction tank of the auxiliary device 120, the auxiliary inflow channel 140 and the auxiliary recovery channel 1
60 is provided, and the other is an auxiliary exhaust passage 15
0 and an auxiliary pressure equalizing channel 170 are provided.
The dynamics of the gas in the first auxiliary adsorption tank 130 and the second auxiliary adsorption tank 131 are the same as those in the first adsorption tank 30 and the second adsorption tank 31 described in the first embodiment.

The opening / closing of each valve in the auxiliary device 120 and the change in pressure inside the adsorption tank are the same as those in the first-stage device 20, and a description thereof will be omitted. (Example) Hereinafter, an example of this embodiment will be described.
First, as an embodiment, a rare gas concentrating device 10 including a first-stage device 20 and an auxiliary device 120 is prepared, a rare gas-containing air having a krypton concentration of 0.5% is introduced into the device, and the krypton concentration in the exhaust gas is reduced. It was measured by chromatography.

The results are shown in Table 2 below.

[0097]

[Table 2]

On the other hand, as a comparative example, a rare gas concentrating device 10 having only the first-stage device 20 was prepared, and a rare gas-containing air having a krypton concentration of 0.2% was introduced into this device. The krypton concentration was measured by gas chromatography. The results are shown in Table 3 below.

[0099]

[Table 3]

The "emission rate" in Tables 2 and 3 indicates the proportion of krypton that has flowed into the exhaust gas. That is, the smaller the number is, the smaller the amount of krypton discharged into the exhaust gas is, which means that more krypton is accumulated in the rare gas concentrator 10. By the way, in the comparative example, the discharge rate was 15.2% on average, while in the example, it was 0.0% even after about 5 hours. Therefore,
Obviously, it has been found that the provision of the auxiliary device 120 causes more krypton to be accumulated in the noble gas concentrator 10.

(Application of the Present Invention) The present invention is applicable to the treatment of radioactive rare gases generated in nuclear power plants.

[0102]

The present invention is configured as described above and has the following effects. That is, according to the rare gas enrichment method and the rare gas enrichment apparatus according to the present invention, it is possible to separate a portion containing no rare gas from the exhaust gas and effectively collect only a portion containing a large amount of the rare gas. For example, it is possible to reduce the volume of gas that requires an attenuation process such as storage for a certain period.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a first embodiment of the present invention.

FIG. 2 is a graph showing a pressure change in an adsorption tank by a gauge pressure according to the first embodiment of the present invention. In addition,
The solid line shows the pressure change in the first adsorption tank, and the broken line shows the pressure change in the second adsorption tank.

FIG. 3 is a time chart showing a valve opening / closing pattern according to the first embodiment of the present invention. It should be noted that the time shown in the figure coincides with the time shown in FIG.

FIG. 4 is a graph showing dynamics of a rare gas according to the first embodiment of the present invention. The solid line indicates the exhaust gas collected from the exhaust sample cock, and the broken line indicates the inflow gas collected from the inflow sample cock.

FIG. 5 is a schematic diagram showing a positional relationship between an adsorption tank, an exhaust passage, and a pressure equalizing passage in a second embodiment of the present invention.

FIG. 6 is a graph showing dynamics of a rare gas according to the second embodiment of the present invention.

FIG. 7 is a schematic diagram showing a third embodiment of the present invention.

FIG. 8 is a front view showing the shape of the suction tank used in the third embodiment of the present invention.

[Explanation of symbols]

 10 Noble gas concentrator 20 First stage device 30 First adsorption tank 31 Second adsorption tank 40 Inflow passage 41 First pump 42 Inflow control valve 43 Second pump 44 Inflow sample cock 45 First pressurization valve 46 Second pump Pressure valve 50 Exhaust flow path 51 First exhaust valve 52 Second exhaust valve 53 Exhaust buffer tank 54 Pressure control valve 55 Exhaust flow control valve 56 Exhaust sample cock 60 Recovery flow path 61 First pressure reducing valve 62 Second pressure reducing valve 65 Recovery buffer tank 70 Equalizing flow passage 71 First equalizing valve 72 Second equalizing valve 80 Additional device 81 First branch 82 First equalizing inflow valve 83 Second equalizing inflow valve 84 Second branch 85 First equalizing outflow valve 86 Second equalizing Pressure outflow valve 87 One-way flow path 88 Equalizing pressure pump 89 Equalizing pressure flow control valve 100 Reference adsorption tank 101 Additional adsorption tank 120 Auxiliary device 130 First auxiliary adsorption tank 131 Second auxiliary adsorption tank 140 Auxiliary inflow channel 143 Auxiliary pump 145 First auxiliary pressurizing valve 146 Second auxiliary pressurizing valve 150 Auxiliary drain Flow path 151 First auxiliary exhaust valve 152 Second auxiliary exhaust valve 153 Auxiliary exhaust buffer tank 154 Auxiliary pressure control valve 160 Auxiliary recovery flow path 161 First auxiliary pressure reducing valve 162 Second auxiliary pressure reducing valve 163 Detour path 164 Rare gas trap 165 Auxiliary recovery buffer tank 170 Auxiliary pressure equalizing channel 171 First auxiliary pressure equalizing valve 172 Second auxiliary pressure equalizing valve

Continuing from the front page (72) Inventor Shinji Masuyama 1-8-20 Kita-Shinagawa, Shinagawa-ku, Tokyo F-term in Giken Co., Ltd. (Reference) 4D012 CA14 CB16 CD07 CE01 CF03 CG01 CH03 CJ02 CJ07 4G066 AA04B BA36 CA12 DA02 GA06 GA14 GA27 GA37 GA39

Claims (8)

[Claims] 1. A pressure adsorption step in which a rare gas-containing air is pressurized into a second adsorption tank containing an adsorbent at a pressure exceeding atmospheric pressure to adsorb the rare gas to the adsorbent, and to the adsorption tank. Releasing the pressurization of, and exhausting the rare gas free air not adsorbed to the adsorbent,
And a method for condensing a rare gas, comprising depressurizing the adsorption tank and depressurizing and desorbing a rare gas-rich air containing the rare gas adsorbed on the adsorbent, wherein the degassing step is repeated. At the same time, the rare gas-containing air is allowed to flow into the adsorption tank in the pressurized adsorption stage under pressure, and in the other adsorption tank, the rare gas-rich air is desorbed in the vacuum desorption stage. When the rare gas-free air is exhausted in the above, a part of the rare gas-free air is transferred to the other adsorption tank, and at the same time, is diluted into the other adsorption tank in the pressure adsorption stage. The gas-containing air is allowed to flow in under pressure, and the rare gas-rich air is desorbed from one of the adsorption tanks in the decompression and desorption step, and at the same time, the other adsorption tank is desorbed. In this method, the pressure adsorption step is continued, and a part or all of the rare gas-rich air desorbed in the desorption step is mixed with the rare gas-containing air and then pressurized and flows into the adsorption tank again. Gas enrichment method. 2. The method according to claim 1, wherein the adsorbent is a carbon-based adsorbent. 3. A second adsorption tank containing an adsorbent, a pressurizing means for causing a rare gas-containing air to flow into the adsorption tank under pressure at a pressure exceeding atmospheric pressure to adsorb the rare gas to the adsorbent, Exhaust means for releasing the pressure to the adsorption tank and exhausting the rare gas-free air not adsorbed to the adsorbent, Equalizing pressure for transferring part of the rare gas-free air between the two adsorption tanks A rare gas concentrator having a pressure reducing means for depressurizing the adsorption tank and desorbing rare gas rich air containing a rare gas adsorbed on the adsorbent, wherein the pressurizing means comprises the second adsorption tank When the rare gas-containing air is pressurized and flows into one of the adsorption tanks, the other adsorption tank is depressurized to form the depressurizing means so as to desorb the rare gas-rich air. When the rare gas-free air is exhausted from one of the adsorption tanks and the equalizing means transfers a part of the rare gas-free air to the other adsorption tank, the other adsorption tank The pressurizing means is formed so as to allow the rare gas-containing air to flow under pressure, and when the depressurizing means desorbs the rare gas-rich air from the one adsorption tank, the other adsorption means A rare gas enriching apparatus, wherein the pressurizing means is formed so that a part or all of the rare gas-rich air desorbed by the depressurizing means is mixed with rare gas-containing air to flow into the tank under pressure. . 4. A pressure equalizing means comprising: (a) two branch flow paths branching in parallel; (b) two one-way valves arranged with one branch flow path with an outflow side facing; C) two one-way valves arranged so that the inflow side faces the other branch flow path; (d) a one-way valve connecting between the one-way valves in (b) and the one-way valve in (c). The rare gas concentrating device according to claim 3, further comprising an additional device having a directional flow path and a flow control device provided in the middle of (e) and (d). 5. A rare gas-rich air desorbed by a pressure reducing means under pressure at a pressure exceeding atmospheric pressure into two auxiliary adsorption tanks containing an adsorbent, and the rare gas is introduced into the adsorbent. An auxiliary pressurizing means for adsorbing, an auxiliary exhausting means for releasing the pressurization of the auxiliary adsorption tank and exhausting the rare gas-free air not adsorbed to the adsorbent; Auxiliary pressure equalizing means for transferring part of gas-free air, and depressurizing the auxiliary adsorption tank to desorb rare gas-rich air containing rare gas adsorbed on the adsorbent, and pressurizing part or all of the air. When the rare gas-rich air is pressurized and flows into one of the two auxiliary adsorption tanks, the other auxiliary pressurizing means has the other auxiliary pressure reducing means. The suction tank is depressurized to form the auxiliary pressure reducing means so that the rare gas rich air is desorbed and part or all of the air is transferred to the pressurizing means, and the auxiliary exhaust means is one of the auxiliary suction tanks When the auxiliary equalizing means transfers a part of the rare gas-free air to the other auxiliary adsorption tank, the rare gas-free air is exhausted from the other auxiliary adsorption tank. The auxiliary pressurizing means is formed so as to pressurize and inflow the gas-rich air, and the auxiliary depressurizing means desorbs the rare gas-rich air from the one auxiliary adsorption tank and transfers part or all of the rare gas-rich air to the pressurizing means. An auxiliary pressurizing means is formed to pressurize and flow the rare gas-rich air desorbed by the depressurizing means into the other adsorption tank at the time of performing the operation. 4 noble gas concentrating apparatus according. 6. The rare gas concentrator according to claim 5, wherein a bypass flow path is provided in the auxiliary pressure reducing means, and the rare gas rich air can be taken out of the system from the bypass flow path. 7. The adsorption tank has a short diameter and a long length, and the equalizing means connects the upper parts of the two adsorption tanks, and the inflow path of the rare gas-containing air by the pressurizing means and the rare gas rich air by the depressurizing means. And a discharge path for rare gas-free air provided by a discharge means is provided at an upper part of the adsorption tank.
7. The rare gas concentrator according to 5 or 6. 8. The rare gas concentrator according to claim 3, wherein the adsorbent is an adsorbent mainly composed of carbon.