TWI414479B - Argon refining method and argon refining device - Google Patents

Abstract

PURPOSE: A method and a device for purifying argon are provided to obtain argon with high purity and yield by using a PSA method. CONSTITUTION: Mixed gas including argon is inputted to a storage bath(10). The mixed gas is supplied from the storage bath to an absorbing tower(31A,31B,31C). The impurity of the mixed gas is absorbed in an absorbent when the pressure is relatively high inside the absorbing tower. Purified gas with much argon is extracted from the absorbing tower. The impurity is desorbed from the absorbent by decreasing the pressure inside the absorbing tower. The gas is extracted from the absorbing tower. The above processes are repeated in the absorbing tower.

Description

Argon gas refining method and argon gas refining device

The present invention relates to a method and apparatus for purifying argon gas by a pressure swing adsorption method.

Argon is often used as an atmosphere in a furnace in a crucible crystal furnace, a ceramic sintering furnace, a chrome steel decarburization furnace, and the like. The argon gas used as the atmosphere gas in the furnace reduces the purity due to the incorporation of impurities. The argon gas used as the atmosphere gas in the furnace may be recovered and recovered by a pressure fluctuation adsorption method (PSA method) for reuse. The refining technique of the argon gas using the PSA method is disclosed in, for example, the following Patent Documents 1 to 4.

[First technical literature]

[Patent Document 1] JP-A-4-69563

[Patent Document 2] Japanese Patent Publication No. 4-17039

[Patent Document 3] Japanese Patent Publication No. 6-166507

[Patent Document 4] Japanese Patent Publication No. 9-201530

The used atmospheric gas containing argon as a main component discharged from a krypton crystal furnace, a ceramic sintering furnace, a chrome steel decarburization furnace, etc., is often accompanied by fluctuations in discharge flow rate, impurity composition, and the like, and there is also a rapid change. . Therefore, in order to continuously refine the exhaust gas discharged from the furnace, it is necessary to construct a processing system that can respond to fluctuations in the flow rate of the exhaust gas, composition fluctuations, and the like. However, in the PSA apparatus for carrying out the PSA method, it is difficult to respond to the inevitable flow rate variation (i.e., load fluctuation) of the material gas supplied to the apparatus. In addition, PSA is not good at responding to changes in the composition of raw material gases.

Further, the used atmospheric gas containing argon as a main component discharged from various furnaces has a relatively high argon gas concentration (for example, an argon gas concentration of 95 vol% or more). In the prior art, it is difficult to further increase the concentration of argon gas in such a high concentration by using the PSA method and achieve high recovery.

In view of the above, an object of the present invention is to provide an argon gas refining method and an argon gas refining apparatus which are suitable for obtaining a high-purity high-purity argon gas by the PSA method.

According to a first feature of the present invention, there is provided an argon gas refining method. In the method, the mixed gas containing argon gas is charged into the storage tank; and the mixed gas is supplied from the storage tank to the adsorption tower which has been filled with the adsorbent. Then, the cycle including the adsorption step and the desorption step is repeated in the adsorption column. In the adsorption step, the mixed gas is introduced into the adsorption tower in a relatively high pressure state in the adsorption tower, so that the adsorbent adsorbs the impurities in the mixed gas, and the argon-rich purified gas is led out from the adsorption tower. In the desorption step, the inside of the adsorption column is depressurized to desorb the impurities from the adsorbent, and the gas is withdrawn from the adsorption column. Further, the desorption step includes a first desorption step of deriving the first gas from the adsorption tower during the start of the desorption step, and a second desorption of the second gas from the adsorption tower after the first desorption step A step is added and the first gas is introduced into the storage tank. In the present method, a single adsorption column may be used, or a plurality of adsorption columns may be used.

In the present method, a pressure swing adsorption method (PSA method) including the above-described adsorption step and desorption step is carried out in an adsorption column, thereby enriching argon gas in the mixed gas. Regarding the mixed gas, after temporarily charging it into the storage tank, the mixed gas is supplied from the storage tank toward the adsorption tower for carrying out the PSA method. Even if the mixed gas of the raw material gas which is the income storage tank is changed in flow rate, composition, etc., the mixed gas is collected in the storage tank and stored and mixed, whereby the flow rate in the mixed gas derived from the storage tank Changes, composition changes, etc. will be suppressed. Therefore, according to this method, even if the argon gas is enriched by the PSA method, it is easy to respond to fluctuations in the flow rate of the material gas, composition fluctuation, and the like.

In addition to this, with the present invention, it is easy to achieve a high yield of enriched argon gas. In the method, in the gas (off gas) continuously derived from the adsorption tower in the desorption step described above, the exhaust gas having a relatively high argon gas concentration is returned to the storage tank, and the exhaust gas is used for use. The enrichment of argon again by the PSA method. The impurity content rate of the exhaust gas derived from the adsorption tower in the desorption step tends to gradually increase from the start of the desorption step, and in the present method, the period of the impurity content of the exhaust gas is sufficiently low. The exhaust gas (first desorbed gas) is introduced into the first desorption step of the storage tank, and when the impurity content of the exhaust gas is at least a certain period, the second degassing of the exhaust gas (second desorbed gas) outside the system can be performed. Attached steps.

As described above, the argon gas refining method related to the first feature of the present invention is suitable for obtaining high-purity argon gas in a high yield by the PSA method.

According to a second feature of the present invention, there is provided an argon gas refining method. In this method, a mixed gas containing argon gas is charged into a storage tank, and a mixed gas is supplied from a storage tank to a plurality of adsorption towers which have been filled with an adsorbent. Then, in the adsorption tower, a cycle including the following adsorption step, depressurization step, desorption step, cleaning step, and pressure increasing step is repeated. In the adsorption step, the mixed gas is introduced into the adsorption tower in a relatively high pressure state in the adsorption tower, so that the adsorbent adsorbs the impurities in the mixed gas, and the argon-rich purified gas is led out from the adsorption tower. In the depressurization step, the inside of the adsorption column is depressurized and the gas is led out from the adsorption column. In the desorption step, the inside of the adsorption column is depressurized to desorb the impurities from the adsorbent, and the gas is withdrawn from the adsorption column. In the cleaning step, the cleaning gas is introduced into the adsorption tower, and the gas is withdrawn from the adsorption tower. The cleaning gas for the cleaning step is the gas that is derived from the adsorption column in the depressurization step. The cleaning step includes a first cleaning step of deriving a first gas from the adsorption tower during the start of the cleaning step, a second cleaning step of deriving a second gas from the adsorption tower after the first cleaning step, and a second cleaning step The gas is introduced into the storage tank. In the step of boosting, the pressure in the adsorption tower is raised.

In the present method, a pressure swing adsorption method (PSA method) including the adsorption step, the pressure reduction step, the desorption step, the cleaning step, and the pressure increasing step described above is carried out in each adsorption column to thereby obtain argon in the mixed gas. Enrichment. Regarding the mixed gas, after temporarily charging it into the storage tank, the mixed gas is supplied from the storage tank toward the adsorption tower for carrying out the PSA method. Even if the mixed gas of the raw material gas which is the income storage tank is changed in flow rate, composition, etc., the mixed gas is collected in the storage tank and stored and mixed, whereby the flow rate in the mixed gas derived from the storage tank Changes, composition changes, etc. will be suppressed. Therefore, according to this method, even if the argon gas is enriched by the PSA method, it is easy to respond to fluctuations in the flow rate of the material gas, composition fluctuation, and the like.

In addition to this, with the present invention, it is easy to achieve a high yield of enriched argon gas. In the present method, among the gas (purge gas) continuously derived from the adsorption tower in the above-described cleaning step, a flushing gas having a relatively high argon gas concentration is introduced into the storage tank, and the flushing is performed. The gas is used for enrichment of argon using the PSA method. The impurity content rate of the flushing gas derived from the adsorption tower in the cleaning step tends to gradually decrease from the start of the cleaning step, and in the present method, the flushing gas (first exhaust gas) can be discharged from the system. In the first cleaning step, the impurity content of the rinsing gas is sufficiently low, and after the impurity content of the rinsing gas is sufficiently low, the rinsing gas (second exhaust gas) can be introduced into the storage tank. Two cleaning steps.

As described above, the argon gas refining method relating to the second feature of the present invention is suitable for obtaining high-purity argon gas in a high yield by the PSA method.

In a second feature of the invention, preferably the desorption step comprises a first desorption step of deriving the first desorbed gas from the adsorption column during the beginning of the desorption step, and after the first desorption step A second desorption step of desorbing the second desorbed gas is derived from the adsorption column, and the first desorbed gas is introduced into the storage tank. Such an operation is useful for obtaining high purity argon gas in high yield. In the method, in the gas (exhaust gas) continuously derived from the adsorption tower in the desorption step described above, the exhaust gas having a relatively high argon gas concentration is returned to the storage tank, and the exhaust gas is supplied as a PSA method again. Enrichment of argon. The impurity content rate of the exhaust gas derived from the adsorption tower in the desorption step tends to gradually increase from the start of the desorption step, and in the present method, the period of the impurity content of the exhaust gas is sufficiently low. The exhaust gas (first desorbed gas) is introduced into the first desorption step of the storage tank, and when the impurity content of the exhaust gas is at least a certain period, the second degassing of the exhaust gas (second desorbed gas) outside the system can be performed. Attached steps.

Preferably, the depressurization step comprises a first depressurization step of deriving the first decompressed gas from the adsorption column during the start of the depressurization step, and deriving from the adsorption column after the first decompression step The second depressurization step of the second decompressed gas, the first decompressed gas is introduced as a cleaning gas into the adsorption column in the cleaning step, and the second decompressed gas is introduced into the adsorption column in the step of increasing pressure. When the argon gas concentration of the gas derived from the adsorption tower in the depressurization step is relatively high, if such a structure is used, the gas derived from the adsorption tower in the depressurization step can be efficiently cleaned in other adsorption towers. Step and boost step. That is, if such a structure is used, the steps performed in a plurality of adsorption columns can be utilized in an integrated manner, and the PSA method for enriching argon gas can be efficiently performed.

Preferably, the lowest pressure in the interior of the adsorption column in the desorption step is 0%, and the maximum pressure in the interior of the adsorption column in the adsorption step is 100%, at the end of the first depressurization step. The first intermediate pressure inside the adsorption tower is in the range of 35 to 80%, and the second intermediate pressure inside the adsorption tower at the end of the second decompression step is less than the limitation of the first intermediate pressure, the second intermediate The pressure is in the range of 15 to 50%. Such a configuration is useful for efficiently performing the cleaning step and the step of boosting.

Preferably, the step of boosting includes introducing a sixth gas derived from the adsorption column in the second depressurization step into the adsorption step of the adsorption target, and refining after the first pressure increase step. A second step of boosting the gas into the adsorption column. Such a configuration is preferable because the adsorption step and the subsequent adsorption step are efficiently performed in each adsorption column.

In the first and second features of the present invention, it is preferred that the lowest pressure inside the adsorption tower in the desorption step is atmospheric pressure or higher. In such a configuration, when the adsorption tower performs the desorption step, it is not necessary to use an active pressure reduction device such as a vacuum pump. In addition, there is no need to use such a configuration of a positive pressure reducing device such as a vacuum pump, since the flow rate of the mixed gas from the storage tank can be varied from the adsorption tower or the PSA device for performing the PSA method (that is, for the device) It is better because the load changes).

Preferably, the flow rate of the mixed gas supplied from the storage tank toward the adsorption tower is updated at the time when the adsorption tower starts the adsorption step. Such a configuration is preferable because it can reduce the load on the adsorption tower or the PSA apparatus for performing the PSA method.

In the first preferred embodiment, the upper side setting amount and the lower side setting amount smaller than the upper side setting amount are set in relation to the storage amount in the storage tank. Therefore, when the supply flow rate of the mixed gas is updated: when the storage amount of the mixed gas in the storage tank is equal to or higher than the upper set amount, the mixed gas supply flow rate is increased; and the storage amount of the mixed gas in the storage tank is lower than the upper set amount and When the amount is higher than the lower setting amount, the mixed gas supply flow rate is not changed; if the storage amount of the mixed gas in the storage tank is equal to or less than the lower side setting amount, the mixed gas supply flow rate is reduced. In such a configuration, the flow rate of the mixed gas of the raw material gas which is the storage tank is changed, and the load is stabilized by the load fluctuation from the storage tank or the PSA apparatus for performing the PSA method. Therefore, it is better.

In the second preferred embodiment, the upper side setting amount and the lower side setting amount smaller than the upper side setting amount are set in the storage amount in the storage tank, and the storage is received before the mixed gas supply flow rate is updated. The flow rate of the mixed gas in the tank (for example, the average flow rate in a predetermined period) is used as the reference flow rate. Therefore, when the supply flow rate of the mixed gas is updated: the storage amount of the mixed gas in the storage tank is equal to or greater than the upper set amount, and the flow rate larger than the reference flow rate is the mixed gas supply flow rate; and the storage amount of the mixed gas in the storage tank When the amount is lower than the upper setting amount and higher than the lower side setting amount, the reference flow rate is the mixed gas supply flow rate; the storage amount of the mixed gas in the storage tank is equal to or less than the lower side setting amount, and the flow rate smaller than the reference flow rate is Mixed gas supply flow. In such a configuration, the flow rate of the mixed gas of the raw material gas which is the storage tank is changed, and the load is stabilized by the load fluctuation from the storage tank or the PSA apparatus for performing the PSA method. Therefore, it is better.

Preferably, the mixed gas is pretreated from the storage tank before the mixed gas is supplied to the adsorption tower, and the purpose of the pretreatment is to remove or change at least a part of the impurities contained in the mixed gas. Such a configuration is preferable because high-purity argon gas can be obtained. Further, such a configuration is preferable because the impurities contained in the mixed gas can be stably removed or changed. The reason for this is that in the present configuration in which the mixed gas from the storage tank in which the flow rate fluctuation is relaxed is applied, it is easy to stabilize the load for the pretreatment.

Preferably, the pre-processing is performed by dividing into a plurality of segments. When the at least one portion of the impurities contained in the mixed gas is removed or changed, the pretreatment to be applied to the mixed gas is subjected to a heat generation reaction, and the pretreatment is divided into a plurality of stages, which can be prevented in the prior treatment. It is preferred that the excessive temperature rises and the reaction temperature is controlled within an appropriate range.

In the case where the mixed gas contains at least carbon monoxide and hydrogen in addition to the argon-containing gas, it is preferred that the pretreatment comprises a first treatment for reacting carbon monoxide with oxygen to generate carbon dioxide, and after the first treatment. A second treatment that produces hydrogen by reacting with oxygen. In such a configuration, in the case where the mixed gas contains carbon monoxide and hydrogen in addition to argon gas, it is preferable to remove or lower the concentration of the carbon monoxide and hydrogen.

In addition, the pretreatment may further include a third treatment performed by reacting hydrogen with oxygen to generate water after the second treatment. Such a configuration prevents an excessive temperature rise in the treatment for generating water by reacting hydrogen with oxygen (in this treatment, hydrogen and water are generated by the exothermic reaction), and the reaction temperature is controlled appropriately. Within the scope, it is preferred. Further, such a configuration is preferable because it removes hydrogen or further reduces the concentration. Further, in such a configuration, the hydrogen concentration of the mixed gas supplied to the adsorption tower can be finally adjusted. Therefore, such a configuration is preferable because a purified gas (high-purity argon gas) can be prepared to contain hydrogen having a predetermined concentration.

According to a third feature of the present invention, an argon gas refining device is provided. The apparatus comprises: an adsorption tower having a first gas passage opening and a second gas passage opening, wherein the first and second gas passage openings are filled with an adsorbent; and a storage tank is used for Before the argon-containing mixed gas is supplied to the adsorption tower, the mixed gas is stored; a first line is connected between the storage tank and the adsorption tower, and the mixed gas is supplied from the storage tank to the first gas passage side of the adsorption tower a second line connecting the first gas passage port side of the adsorption tower and having an exhaust end; and a third line (recovery line) connecting the second line and the storage tank. According to the present apparatus having such a configuration, the method for purifying the argon gas according to the first aspect of the present invention can be suitably carried out.

According to a fourth feature of the present invention, an argon gas refining device is provided. The apparatus comprises: a plurality of adsorption towers having a first gas passage opening and a second gas passage opening, wherein the first and second gas passage openings are filled with an adsorbent; and a storage tank is used for Before the argon-containing mixed gas is supplied to the adsorption tower, the mixed gas is stored; a first line is connected between the storage tank and each of the adsorption towers, and the first gas that supplies the mixed gas from the storage tank to each adsorption tower is passed a second line comprising a main road having an exhaust end, and a plurality of branch paths disposed on each of the adsorption towers to connect the first gas passages of the adsorption towers; and a third line including the trunk And a plurality of branch paths that are disposed on each of the adsorption towers and connect the second gas of each adsorption tower to the adsorption side; and a fourth line that connects the second line and the storage tank. According to the present apparatus having such a configuration, the method for purifying the argon gas according to the second feature of the present invention can be suitably carried out.

The argon gas refining device according to the third and fourth features of the present invention preferably further includes means for detecting the storage amount in the storage tank, and a mixed gas for controlling supply from the storage tank toward the adsorption tower. The device of the flow. Such a configuration is preferable because the flow rate of the mixed gas supply according to the first preferred embodiment described above can be updated.

The argon gas purifying apparatus according to the third and fourth features of the present invention preferably further includes means for detecting the storage amount in the storage tank, and controlling the mixed gas supplied from the storage tank toward the adsorption tower. A device for flow, and a device for detecting a flow rate of a mixed gas supplied to the storage tank. Such a configuration is preferable because the flow rate of the mixed gas supply according to the second preferred embodiment described above can be updated.

Preferably, a pretreatment system for performing a pretreatment is provided on the first line, and the purpose of the pretreatment is to remove or change at least a portion of the impurities contained in the mixed gas. Such a configuration is preferable because high-purity argon gas can be obtained. Further, such a configuration is preferable because the impurities contained in the mixed gas can be stably removed or changed. The reason for this is that in the present configuration in which the mixed gas from the storage tank in which the flow rate fluctuation is relaxed is applied, it is easy to stabilize the load for the pretreatment.

Preferably, the pre-processing system includes a plurality of processing slots for dividing the pre-processing into a plurality of segments. When the at least one portion of the impurities contained in the mixed gas is removed or changed, the pretreatment to be applied to the mixed gas includes a pyrolysis reaction, and includes a plurality of pretreatment systems for dividing the pretreatment into a plurality of stages. It is preferable since the excessive temperature rise can be prevented and the reaction temperature is controlled within an appropriate range in the previous treatment.

In the case where the mixed gas contains at least carbon monoxide and hydrogen in addition to the argon-containing gas, it is preferred that the pretreatment system includes a first treatment tank and a second treatment tank, and the first treatment tank is used to carry out A first treatment in which carbon monoxide reacts with oxygen to produce carbon dioxide, and a second treatment tank is used to perform a second treatment of reacting hydrogen with oxygen to produce water after the first treatment. In such a configuration, in the case where the mixed gas contains carbon monoxide and hydrogen in addition to argon gas, it is preferable to remove or lower the concentration of the carbon monoxide and hydrogen.

In addition, the pretreatment system may further comprise a third treatment tank which performs a third treatment which has been carried out after the second treatment to react hydrogen with oxygen to produce water. Such a configuration prevents an excessive temperature rise in the treatment for generating water by reacting hydrogen with oxygen (in this treatment, hydrogen and water are generated by the exothermic reaction), and the reaction temperature is controlled appropriately. Within the scope, it is preferred. Further, such a configuration is also preferable because it is required to remove hydrogen or further reduce the concentration. Further, such a configuration is preferable because a purified gas (high-purity argon gas) can be prepared to contain hydrogen having a predetermined concentration.

[Best form for implementing the invention]

Fig. 1 is a view showing the overall schematic configuration of an argon gas purifying apparatus Y according to the present invention. Y is an argon gas refining device having a storing system, pretreatment system 2, PSA system 3, line 4 and recycled, recovered raw material gas containing argon gas by G ₀ and a continuous purification is argon.

The source gas G ₀ is an argon gas which is used for a furnace atmosphere gas in a kiln furnace, a ceramic sintering furnace, a chrome steel decarburization furnace, or the like, and is mixed with impurities, and is continuous from at least one furnace (not shown). Or intermittently discharged. The discharge flow rate, pressure, composition, and the like of the exhaust gas (the material gas G ₀ ) often fluctuate depending on the steps in the execution of the furnace, the operating conditions of the furnace, and the like, and may be violently changed. The material gas G ₀ contains argon as a main component and contains hydrogen, nitrogen, carbon monoxide, and oxygen. The main impurity is, for example, hydrogen. The discharge flow rate of the material gas G ₀ from the furnace (that is, the supply flow rate of the material gas G ₀ flowing to the argon gas refining device Y) is, for example, 100 to 500 Nm ³ /h.

The storage system 1 which is a part of the argon gas refining device Y has a buffer tank 10, a dust remover 11, a booster blower 12, and a flow meter 13 as shown in Figs. 1 and 2 . The storage amount detector 14, the concentration analyzer 15, the flow rate control unit 16, and the line 17 having the material gas introduction end E1. The dust remover 11, the flow meter 13, the buffer tank 10, the booster blower 12, and the flow rate control unit 16 are arranged in-line in the line 17.

The buffer tank 10 is for temporarily storing a mixed gas containing argon gas (including the material gas G ₀ ). Further, in the present embodiment, the buffer tank 10 is configured to have a variable volume. The buffer tank 10 whose volume is variable is formed, for example, by a retractable cloth container to form a storage space. The maximum volume of the buffer tank 10 is, for example, 100 to 200 m ³ . The variable volume of the buffer tank 10 is set to the upper set value V _H and the lower set value V _L . The upper set value V _{H is,} for example, 80 to 160 m ³ . The lower set value V _{L is,} for example, 40 to 80 m ³ .

The dust remover 11 removes a solid component of a large amount of dust, metal powder, or the like contained in the material gas G ₀ of the exhaust gas from the furnace from the source gas G ₀ . Such a dust remover 11 is disposed on the upstream side of the buffer tank 10 and has, for example, a predetermined dust filter.

Booster blower 12 is disposed on the downstream side of the buffer tank 10, and to the raw material gas G ₀ incorporated into the buffer tank 10 and the actuator. By actuation, the negative pressure booster blower 12 in the gas reservoir in the buffer tank 10 leaving space for the raw material gas G ₀ appropriately flows into the buffer tank 10. Further, by actuating the booster blower 12, a gas G ₁ is derived from the buffer tank 10, the processing system 2 toward the front out of this gas G _1.

The flow meter 13 is a flow rate of the inflow buffer tank 10 that measures the source gas G ₀ of the exhaust gas from the furnace. The storage amount detector 14 measures the storage amount of the gas that is being stored in the buffer tank 10.

The concentration analyzer 15 measures the concentration of each impurity contained in the gas G ₁ passing through the buffer tank 10 and the booster blower 12. Specifically, the concentration analyzer 15 measures the respective concentrations of hydrogen, nitrogen, carbon monoxide, and oxygen contained in the gas G ₁ .

The flow rate control unit 16 controls the flow rate of the gas G ₁ supplied to the subsequent stage of the pretreatment system 2 or the like. Such a flow rate control unit 16 is configured, for example, as a valve that can control the degree of opening and closing.

The pretreatment system 2 which is a part of the argon gas refining device Y is an impurity which is difficult to remove by the pressure fluctuation adsorption method (PSA method) which is carried out in the PSA system 3 in the subsequent stage. Examples of the impurities removed in the pretreatment system 2 include oxygen and water. Since oxygen is often harmful when the purified argon gas is reused as an atmosphere gas in the furnace, it is highly necessary to remove it. As shown in FIGS. 1 and 3, the pretreatment system 2 includes pretreatment tanks 20A, 20B, and 20C, a preheater 21, coolers 22A, 22B, and 22C, and hydrogen supply amount control units 24A, 24B, and 24C. Thermometers 25A, 25B, and 25C, flow rate control units 26A and 26B, hydrogen concentration analyzer 27, lines 28A, 28B, 28C, and 28D, and bypass lines 28b and 28c. The pretreatment tanks 20A, 20B, and 20C are in a state of being connected in series in the gas flow path.

The pretreatment tank 20A is a conversion reaction tank for substantially removing carbon monoxide in the gas G ₁ into carbon dioxide (carbon monoxide is catalytically toxic to the catalyst filled in the pretreatment tanks 20B, 20C in the latter stage). Case), having an inlet end 20a and an outlet end 20b. In the pretreatment tank 20A, a catalyst which promotes the conversion reaction represented by the following reaction formula (1) is filled. It can be used as a catalyst for the catalyst, such as a platinum-based catalyst, a palladium-based catalyst, or a platinum-palladium fine catalyst.

【化1】

The pretreatment tank 20B is a conversion reaction tank for reducing the concentration of hydrogen and oxygen in the gas G ₁ derived from the outlet end 20 b of the pretreatment tank 20A into water after passing through the treatment in the pretreatment tank 20A or Substantially removed, it has an inlet end 20a and an outlet end 20b. In the pretreatment tank 20B, a catalyst which promotes the conversion reaction represented by the following reaction formula (2) is filled. It can be used as a catalyst for such a catalyst, such as a platinum-based catalyst or a ruthenium-based catalyst.

[Chemical 2]

The pretreatment tank 20C is a conversion reaction tank for reducing the concentration of hydrogen and oxygen in the gas G ₁ derived from the outlet end 20 b of the pretreatment tank 20B into water after passing through the treatment in the pretreatment tank 20B or Substantially removed, it has an inlet end 20a and an outlet end 20b. The pretreatment tank 20C is filled with a catalyst that promotes the conversion reaction represented by the above reaction formula (2). It can be used as a catalyst for such a catalyst, such as a platinum-based catalyst or a ruthenium-based catalyst.

The preheater 21 is configured to heat the gas G ₁ before reaching the pretreatment tank 20A, for example, by an electric heater. The hydrogen supply amount control unit 23 is connected to the hydrogen storage unit outside the drawing, and is connected to the line 28A connected to the inlet end 20a of the pretreatment tank 20A. The hydrogen supply amount control unit 23 is configured to control the flow rate of hydrogen supplied from the hydrogen storage unit to the line 28A in response to a demand, and is constituted by, for example, a valve that can control the degree of opening and closing, the open state time, and the like. The thermometer 25A is a temperature of the gas G ₁ before the introduction of the pretreatment tank 20A.

The cooler 22A is provided on the line 28B for cooling the gas G ₁ derived from the outlet end 20b of the pretreatment tank 20A through the treatment in the pretreatment tank 20A. The cooler 22A is constituted, for example, by a heat exchanger using cooling water as a cooling medium. The bypass line 28b is disposed in parallel with the cooler 22A, and the bypass line 28b is provided with a flow rate control unit 26A. The flow rate control unit 26A is constituted by, for example, a valve that can control the degree of opening and closing, the time of opening, and the like. The oxygen supply amount control unit 24B is connected to the oxygen storage unit outside the drawing and is connected to the line 28B. The oxygen supply amount control unit 24B is configured to control the flow rate of oxygen supplied from the oxygen storage unit to the line 28B in response to the demand, and is constituted, for example, by a valve that can control the opening degree, the opening state time, and the like. The thermometer 25B is a temperature of the gas G ₁ before the introduction of the pretreatment tank 20B.

The cooler 22B is provided on the line 28C for cooling the gas G ₁ derived from the outlet end 20b of the pretreatment tank 20B through the treatment in the pretreatment tank 20B. The cooler 22B is constituted, for example, by a heat exchanger using cooling water as a cooling medium. The bypass line 28c is disposed in parallel with the cooler 22B, and the bypass line 28c is provided with a flow rate control unit 26B. The flow rate control unit 26B is constituted by, for example, a valve that can control the degree of opening and closing, the time of opening, and the like. The oxygen supply amount control unit 24C is connected to the oxygen storage unit outside the drawing and is connected to the line 28C. The oxygen supply amount control unit 24C is configured to control the flow rate of oxygen supplied from the oxygen storage unit to the line 28C in response to the demand, and is constituted, for example, by a valve that can control the opening degree, the opening state time, and the like. It is the concentration of hydrogen analyzer 27 before adding oxygen to the gas flow line G ₁ 28C, measurement of the hydrogen concentration in the gas G _1. The thermometer 25C is a temperature of the gas G ₁ before the introduction of the pretreatment tank 20C.

The cooler 22C is provided on the line 28D for cooling the gas G ₁ derived from the outlet end 20b of the pretreatment tank 20B through the treatment in the pretreatment tank 20C. The cooler 22C is constituted, for example, by a heat exchanger using cooling water as a cooling medium.

The pretreatment system 2 in the present embodiment is a conversion reaction tank having three stages as described above. However, because should the gas G ₁ supplied to the type and amount of gas from the PSA system before the 3 G ₁ is desired to remove impurities, the pretreatment system can also be configured as a conversion reaction vessel 2 includes a segment, or conversion of the reaction vessel Sec Or a four-stage conversion reaction tank. Alternatively, the gas G ₁ supplied to the case from the PSA system is not desired to remove the gas before the G ₁ 3 impurities, the pretreatment system can not set 2.

The PSA system 3 which is a part of the argon gas refining device Y has the PSA device 30 as shown in Figs. 1 and 4 . The PSA unit 30 has adsorption towers 31A, 31B, and 31C, a pressure increaser 32, and lines 33 to 36, which utilize a pressure fluctuation adsorption method (PSA method) of gas G ₁ (argon-containing gas) from the pretreatment system 2, and The argon gas was separated by concentration.

Adsorption columns 31A, 31B, 31C each having a gas passage openings 31a, 31b at both ends, and the impurity gas in the adsorbent 31a, between 31b, selectively adsorbing the gas filling to be useful included in G ₁ through opening. For example, carbon molecular sieves (CMS) can be used as an adsorbent for adsorbing carbon dioxide as an impurity. For example, zeolite molecular sieves (ZMS) can be used as an adsorbent for adsorbing nitrogen, carbon monoxide or the like as an impurity. For example, alumina can be used as an adsorbent for adsorbing moisture as an impurity. One type of adsorbent may be charged in the adsorption towers 31A, 31B, and 31C, or a plurality of adsorbents may be charged in the adsorption towers 31A, 31B, and 31C. The type and amount of the adsorbent charged in the adsorption towers 31A, 31B, and 31C are determined in accordance with the type and amount of impurities to be removed in the adsorption towers 31A, 31B, and 31C.

The booster 32 has a gas suction port 32a and a gas delivery port 32b. The gas suction port 32a is coupled to the wire 28D in the pretreatment system 2. This object booster 32 from the gas inlet port 32a is sucked from the gas feeding the gas G ₁ toward the outlet 32b adsorption column 31A, 31B, 31C and out the supply, for example a compressor.

The line 33 has a trunk line 33' and branch paths 33A, 33B, 33C. The trunk line 33' is a gas delivery port 32b to which the booster 32 is connected. The branch paths 33A, 33B, and 33C are connected to the adsorption towers 31A, 31B, and 31C, respectively. Each gas passes through the port 31a side. Automatic valves 33a, 33b, and 33c that can be switched between an open state and a closed state are attached to the branch paths 33A, 33B, and 33C.

The line 34 has a trunk road 34' and branch paths 34A, 34B, 34C. The trunk road 34' has a purified gas lead-out end E2, and the branch paths 34A, 34B, 34C are gases that are connected to the adsorption towers 31A, 31B, and 31C, respectively. Port 31b side. Automatic valves 34a, 34b, and 34c that can be switched between an open state and a closed state are attached to the branch paths 33A, 33B, and 33C.

The line 35 has a trunk line 35' and branch paths 35A, 35B, and 35C, and the branch paths 35A, 35B, and 35C are side of the respective gas passage ports 31b to which the adsorption towers 31A, 31B, and 31C are connected. Automatic valves 35a, 35b, and 35c that can be switched between an open state and a closed state are attached to the branch paths 35A, 35B, and 35C.

The line 36 has a trunk road 36' and branch paths 36A, 36B, 36C, the trunk road 36' has a gas discharge end E3, and the branch paths 36A, 36B, 36C are respective gas passage ports respectively connected to the adsorption towers 31A, 31B, 31C. 31a side. Automatic valves 36a, 36b, and 36c that can be switched between an open state and a closed state are attached to the branch paths 36A, 36B, and 36C.

The PSA system 3 or the PSA unit 30 in the present embodiment has the adsorption towers 31A, 31B, and 31C as described above. However, the PSA system 3 may be configured to include one adsorption tower, two adsorption towers, or four or more adsorption towers.

The recovery line 4 which is a part of the argon gas refining device Y is connected to the line 36 in the PSA system 3 or the PSA unit 30 and the buffer tank 10 in the storage system 1 as shown in Fig. 1 . On the recovery line 4, an automatic valve 4a that can be switched between an open state and a closed state is attached. In the recovery line 4, the predetermined gas discharged from the respective gas passage ports 31a of the adsorption towers 31A, 31B, and 31C in the PSA apparatus is returned to the buffer tank 10.

The argon gas refining method according to the present invention can be carried out by using the argon refining device Y having the above configuration.

In reserving system 1, the booster blower 12 actuated, and the raw material gas G ₀ is received from the feed gas inlet end E1 line 17. The received raw material gas G ₀ is removed by the precipitator 11 to remove a predetermined solid component, and after the flow meter 13 receives the flow rate, it is taken into the buffer tank 10. In the buffer tank 10, a predetermined gas is also received from the PSA system 13. The volume of the gas storage space in the buffer tank 10 is variable as described above, and the gas storage amount stored in the buffer tank 10 or its gas storage space is measured by the storage amount detector 14. Then, the gas G _{1 is} led out from the buffer tank 10. Regarding the gas G ₁ , the concentration of each impurity is measured by the concentration analyzer 15 . The hydrogen concentration measured by the concentration analyzer 15 is X ₁₀ , the oxygen concentration is X ₂₀ , and the carbon monoxide concentration is X ₃₀ . Further, regarding the gas G ₁ , the flow rate is controlled by the flow rate control unit 16 . The flow rate of the gas G ₁ is updated at the time of the adsorption step described later (when the adsorption column is switched) at the start of any of the adsorption columns 31A, 31B, and 31C in the PSA system 3. Specifically, the flow rate of the gas G ₁ is updated as described below.

First, the flow rate of the material gas G ₀ measured by the flow meter 13 is determined such that one of the adsorption towers 31A, 31B, and 31C is at the start of the adsorption step described later (when the adsorption tower is switched). The average flow rate for a given time (for example, 10 seconds) is used as the reference flow rate. Next, it is converted into the estimated average flow rate (reference flow rate) with respect to the estimated or set load flow rate range for the entire device, that is, the flow rate control range of the flow rate control unit 16 (for example, 0 to 400 Nm ³ /h). Proportion (α%). Using this ratio (α%), the flow rate to be set next for the gas G1 is calculated. For example, when the gas storage amount of the buffer tank 10 measured by the storage amount detector 14 is equal to or higher than the above-described upper setting value V _H at the time of the adsorption tower switching, β% is added to α%, and the flow rate control unit 16 is calculated. The flow rate is controlled by (α + β)% of the flow rate range (for example, 0 to 400 Nm ³ /h), and the calculated flow rate is used as the next flow rate of the gas G ₁ . For example, when the gas storage amount of the buffer tank 10 measured by the storage amount detector 14 is equal to or less than the lower side set value V _L described above, the flow rate control unit 16 is calculated by subtracting β% from α%. The flow rate of the flow control range (for example, 0 to 400 Nm ³ /h) is (α - β)%, and the calculated flow rate is used as the next flow rate of the gas G ₁ . For example, when the gas storage amount of the buffer tank 10 measured by the storage amount detector 14 at the time of the adsorption tower switching is lower than the above-described upper setting value V _H and higher than the lower setting value V _L described above, the flow rate is calculated. The flow rate of the control unit 16 (for example, 0 to 400 Nm ³ /h) is a flow rate of α%, and the calculated flow rate is used as the next flow rate of the gas G ₁ . As for the flow rate of the update of the gas G _1, the flow control unit 16 is maintained until the next adsorption Taqie change so far.

The value of β which is a parameter in the flow rate update can be set in accordance with the fluctuation amount, the fluctuation time, and the like in the limit that can be grasped in advance for the flow rate of the material gas G ₀ . By appropriately selecting the value of β can be suppressed in the gas reserving an amount of variation within the buffer tank 10, the buffer tank 10 from the gas supplying the gas G ₁ G ₁ flow stabilization. As a result, load fluctuations such as changes in the flow rate of the gas G ₁ in the pretreatment system 2 and the PSA system 3 in the subsequent stage can be reduced, and the load can be stabilized.

The gas G ₁ that is subjected to the flow rate control by the flow rate control unit 16 is supplied to the pretreatment system 2. In the pretreatment system 2, the gas G ₁ is sequentially subjected to removal of carbon monoxide in the pretreatment tank 20A (first treatment), reduction in hydrogen concentration in the pretreatment tank 20B, or removal of hydrogen (second treatment), The adjustment of the hydrogen concentration in the pretreatment tank 20C or the removal of hydrogen (third treatment). Specifically, in the pretreatment tank 20A, as described above, the carbon monoxide in the gas G ₁ is converted into carbon dioxide by the conversion reaction represented by the reaction formula (1), and is substantially removed. Processing tank 20B in the front, as described above, by the reaction of formula (2) Conversion reaction of the Table ₁ and the gas G of hydrogen and oxygen into water to which a low concentration or substantially removed. 20C in the first treatment tank, as described above, by the conversion reaction of formula (2) in Table ₁ and the gas G of hydrogen and oxygen into water to which a low concentration or substantially removed.

The temperature of the gas G ₁ is adjusted before the gas G _{1 is} introduced into the pretreatment tank 20A. Specifically, the temperature measured by the thermometer 25A gas G ₁ is allowed to warm to line 28A, for example, 130 ~ 150 ℃ sometimes through the preheater 21. Thereby, the reaction temperature of the pretreatment tank is made into, for example, 250 ° C or lower. In order to promote the conversion reaction shown in the above reaction formula (1), the reaction temperature in the pretreatment tank 20A is preferably 130 ° C or higher. The reaction temperature in the pretreatment tank 20A is preferably 250 ° C or less in the reaction for sufficiently suppressing the generation of methane in the pretreatment tank 20A.

In the prior 20A, the gas G _1, by the hydrogen supply amount control unit for the actuator 23 and the additional gas G ₁ introduced into the pretreatment tank depending on the needs of both the amount of hydrogen, and by actuating the oxygen supply quantity control unit 24A is added Quantitative oxygen as needed. The amount of hydrogen added is determined based on the hydrogen concentration X ₁₀ measured by the concentration analyzer 15 described above. The hydrogen concentration of the gas G ₁ introduced into the pretreatment tank 20A after the addition of hydrogen is X ₁₁ . The amount of oxygen added is determined based on the oxygen concentration X ₂₀ and the carbon monoxide concentration X ₃₀ measured by the concentration analyzer 15 described above. The oxygen concentration of the gas G ₁ introduced into the pretreatment tank 20A after the addition of oxygen is X ₂₁ . In order to promote the above reaction formula (1) into the reaction while the pretreatment tank Table 20A sufficiently remove carbon monoxide, oxygen gas G is introduced into the pretreatment tank ₁ contained, is preferably introduced into the pretreatment tank 20A is contained in the gas G ₁ 1.0 to 1.5 times the equivalent of carbon monoxide. In the pretreatment tank 20A, as described above, the conversion reaction shown in the above reaction formula (1) occurs, and carbon monoxide in the gas G ₁ is turned into carbon dioxide to be substantially removed.

After the first treatment tank 20A, a gas G ₁ introduced into the pretreatment tank prior 20B, regulating the temperature of the gas G _1. Specifically, by adjusting the gas cooler is provided through line 22A, 28B as the flow rate ratio of the main line through a bypass line 28b of the gas, and the temperature of the gas G ₁ introduced before the pre-treatment is adjusted to the groove 20B The temperature measured by the thermometer 25B is, for example, 50 to 60 °C. The adjustment of the flow rate ratio is performed by the operation of the flow rate control unit 26A. By such a method, the reaction temperature in the pretreatment tank 20B is, for example, 100 to 350 °C. In order to promote the conversion reaction shown in the above reaction formula (2), the reaction temperature in the pretreatment tank 20B is preferably from 100 to 350 °C. In addition, it is assumed that water as a by-product is generated by the reaction of hydrogen and oxygen in the pretreatment tank 20A in the preceding stage, and moisture is introduced into the pretreatment tank 20B because the activity of the catalyst in the pretreatment tank 20B is active. The temperature of the gas G ₁ is preferably a condensation temperature (for example, 50 ° C) or more.

G ₁ prior to the gas introduced into the pretreatment tank 20B, the gas G _1, the oxygen supply quantity control unit by the actuation of 24B which is added a predetermined amount of oxygen as needed. The amount of oxygen added is determined based on the oxygen concentration X ₂₀ and the carbon monoxide concentration X ₃₀ measured by the concentration analyzer 15 described above and the amount of oxygen added before the pretreatment tank 20A. The oxygen concentration of the gas G ₁ introduced into the pretreatment tank 20B after the addition of oxygen is X ₂₂ . Conversion of the above-described reaction formula (2) in Table reaction is an exothermic reaction, introduction of oxygen contained in the groove 20B pretreatment gas G _1, the amount is preferably 350 deg.] C reaction temperature of the pretreatment is not more than the groove 20B. In the pretreatment tank 20B, as described above, the conversion reaction shown in the above reaction formula (2) occurs, and hydrogen and oxygen in the gas G ₁ are turned into water to be substantially removed or reduced in concentration.

After the first treatment tank 20B, the gas introduced into the pretreatment tank G ₁ prior to 20C, adjusting the temperature of the gas G _1. Specifically, by adjusting the gas provided through the main line to the line 28C cooler 22B as the ratio of the flow through the bypass line 28c of gas, and the temperature of the gas G ₁ introduced before the pre-treatment tank was adjusted to 20C to The temperature measured by the thermometer 25C is, for example, 50 to 60 °C. The adjustment of the flow rate ratio is performed by the operation of the flow rate control unit 26B. By such a method, the reaction temperature in the pretreatment tank 20C is, for example, 100 to 350 °C. In order to promote the conversion reaction shown in the above reaction formula (2), the reaction temperature in the pretreatment tank 20B is preferably from 100 to 350 °C. Further, since the water will become an active catalyst in the pretreatment tank due to encumber 20C, 20C is introduced into the treatment tank temperature gas G ₁ is a front, preferably condensation temperature (e.g. 50 ℃) above.

G ₁ prior to the gas introduced into the pretreatment tank 20C, after the hydrogen concentration of analyte concentration determination of hydrogen gas G ₁ meter 27, both of the added amount of oxygen as needed by the oxygen supply quantity control unit 24C actuation. The hydrogen concentration of the gas G ₁ introduced into the pretreatment tank 20C is X ₁₃ . The amount of oxygen added is based on the oxygen concentration X ₂₀ and the carbon monoxide concentration X ₃₀ measured by the concentration analyzer 15 described above, the amount of oxygen added before the pretreatment tank 20A, the amount of oxygen added before the pretreatment tank 20B, and It is determined by the hydrogen concentration X ₁₃ measured by the hydrogen concentration analyzer 27. The oxygen concentration of the gas G ₁ introduced into the pretreatment tank 20C after the addition of oxygen is X ₂₃ . To by the above reaction formula (2) into the reaction while the pretreatment tank Table 20C to remove oxygen gas G is hydrogen, introduced into the pretreatment tank ₁ contained in the 20C, is preferably introduced into the pretreatment tank of gas G 20C ₁ 1/2 equivalent of hydrogen contained in 1. Further, in order to lower the concentration of hydrogen in the gas G ₁ to a predetermined level, X _{23 is} adjusted to a predetermined value in the range of 1/2X ₁₃ > X ₂₃ . In the pretreatment tank 20C, as described above, the conversion reaction shown in the above reaction formula (2) occurs, and hydrogen and oxygen in the gas G ₁ are turned into water to be substantially removed or reduced in concentration. In the case where hydrogen is removed from the argon gas purified by the argon purifying apparatus Y, in the case where the pretreatment tank 20B can sufficiently remove hydrogen, it is not necessary to arrange the temperature adjusting means in the pretreatment tank 20C and immediately before it. Wait.

After pre-treatment tank 20C, by adjusting the temperature of the gas G ₁ through the cooler 22C. The temperature of the gas G ₁ after passing through the cooler 22C is, for example, 20 to 40 °C.

The gas G ₁ that has been subjected to the predetermined pretreatment in the pretreatment is supplied to the PSA system 3. In the PSA system 3 and the recovery line 4, when the PSA device 30 is driven, the automatic valves 33a to 33c, 34a to 34c, 35a to 35c, and 36a are switched in the manner shown in Figs. 5 to 7 36d, 4a, thereby realizing the flow state of the desired gas in the device, and repeating the cycle constituted by the following steps 1 to 15 (in the fifth to seventh figures, the automatic valve is indicated by ○ The open state and the closed state are indicated by x). In one cycle of the method, each of the adsorption columns 31A, 31B, and 31C performs an adsorption step, a first depressurization step, a second decompression step, a first desorption step, a second desorption step, and a first cleaning. a step, a second cleaning step, a first step of boosting, and a second step of boosting. Fig. 8 is a view showing the flow state of the gas in the PSA unit 30 in the steps 1 to 5. Fig. 9 is a view showing the flow state of the gas in the PSA unit 30 in the steps 6 to 10. Fig. 10 is a view showing the flow state of the gas in the PSA unit 30 in the steps 11 to 15.

In step 1, as shown in Fig. 5, the opening and closing state of each automatic valve is selected, and the operation of the booster 32 is performed to achieve the gas flow state as shown in Fig. 8(a), and in the adsorption tower 31A. The adsorption step is performed, the first cleaning step is performed in the adsorption column 31B, and the first depressurization step is performed in the adsorption column 31C.

Referring also to FIG.4 and FIG. 8 (a) and may be more readily understood in step 1, the gas G is introduced into _a gas adsorption column 31A of a predetermined high-pressure state through the mouth 31a side, so that the adsorption tower 31A the adsorbent gas G ₁ in this impurity (carbon dioxide, water, nitrogen, etc.), argon enriched purified gas G ₂ is derived from the adsorption tower through a gas inlet 31A side 31b. The purified gas G ₂ is taken out from the purified gas outlet end E2 via the line 34 and taken out of the apparatus. At the same time, in step 1, the inside of the adsorption tower 31C which has passed through the steps 1 to 15 (adsorption step) described later is stepped down, and the gas G _{3 is} led out from the gas passage opening 31b side of the adsorption tower 31C. This gas G ₃ is guided to the adsorption tower 31B via the line 35. At the same time, in step 1, the gas G ₃ from the adsorption tower 31C is introduced as a cleaning gas to the gas passage port 31b side of the adsorption tower 31B which has passed through the step 15 (second desorption step) described later. The gas G ₃ ' (flushing gas) is led out from the gas passage opening 31a side of the adsorption tower 31B. This gas G ₃ ' is discharged from the gas discharge end E3 to the outside of the apparatus via the line 36.

In step 2, as shown in Fig. 5, the opening and closing state of each automatic valve is selected, and the operation of the booster 32 is performed to achieve the gas flow state as shown in Fig. 8(b), and in the adsorption tower 31A. The adsorption step is performed, the second cleaning step is performed in the adsorption column 31B, and the first depressurization step is performed in the adsorption column 31C.

Referring to Fig. 4 and Fig. 8(b) together, it can be more easily understood that in step 2, the adsorption step is performed in the adsorption tower 31A following the step 1, and the purified gas G ₂ is derived. At the same time, in the step 2, the first depressurization step is performed in the adsorption tower 31C following the step 1. At the same time, in the second step, the gas G ₃ from the adsorption tower 31C is introduced as a cleaning gas to the gas passage port 31b side of the adsorption tower 31B, and the gas is led out from the gas passage port 31a side of the adsorption tower 31B. G ₃ ” (flushing gas). This gas G ₃ ′′ is introduced into the buffer tank 10 via the line 36 and the recovery line 4 , and is stored in the buffer tank 10 .

In step 3, as shown in Fig. 5, the opening and closing state of each automatic valve is selected, and the operation of the booster 32 is performed to achieve the gas flow state as shown in Fig. 8(c), and in the adsorption tower 31A. The adsorption step is performed, the first pressure increasing step is performed in the adsorption column 31B, and the second pressure reduction step is performed in the adsorption column 31C.

Referring to Fig. 4 and Fig. 8(c) together, it can be more easily understood that in step 3, the adsorption tower 31A is followed by step 2 to carry out the adsorption step, and the purified gas G ₂ is derived. At the same time, in step 3, the adsorption tower 31C is connected to step 2 to lower the inside of the adsorption tower 31C, and the gas G _{4 is} led out from the gas passage opening 31b side of the adsorption tower 31C. The gas G ₄ is guided to the adsorption tower 31B via the line 35. At the same time, in step 3, the gas G ₄ from the adsorption tower 31C is introduced as a pressurized gas to the gas passage port 31b side of the adsorption tower 31B, and the inside of the adsorption tower 31B is pressurized.

In step 4, as shown in Fig. 5, the opening and closing state of each automatic valve is selected, and the operation of the booster 32 is performed to achieve the gas flow state as shown in Fig. 8(d), and in the adsorption tower 31A. The adsorption step is performed, the second pressure increasing step is performed in the adsorption column 31B, and the first desorption step is performed in the adsorption column 31C.

Referring to Fig. 4 and Fig. 8(d) together, it can be more easily understood that in step 4, the adsorption step is carried out in the adsorption column 31A following the step 3, and the purified gas G ₂ is derived. A part of the purified gas G ₂ is guided to the adsorption tower 31B. At the same time, in step 4, the purified gas G ₂ from the adsorption tower 31A is introduced as a pressurized gas to the gas passage port 31b side of the adsorption tower 31B, and the inside of the adsorption tower 31B is pressurized. At the same time, in step 4, the inside of the adsorption tower 31C is depressurized, and the impurities are desorbed from the adsorbent in the adsorption tower 31C, and the gas G ₅ (exhaust gas) is led out from the gas passage opening 31a side of the adsorption tower 31C. . This gas G ₅ is introduced into the buffer tank 10 via the line 36 and the recovery line 4, and is stored in the buffer tank 10.

In step 5, as shown in Fig. 5, the opening and closing state of each automatic valve is selected, and the operation of the booster 32 is performed to achieve the gas flow state as shown in Fig. 8(e), and in the adsorption tower 31A. The adsorption step is performed, the second pressure increasing step is performed in the adsorption column 31B, and the second desorption step is performed in the adsorption column 31C.

Referring to Fig. 4 and Fig. 8(e) together, it can be more easily understood that in step 5, the adsorption step is carried out in the adsorption column 31A following the step 4, and the purified gas G ₂ is derived. A part of the purified gas G ₂ is guided to the adsorption tower 31B. At the same time, in step 5, the adsorption tower 31B is connected to step 1 to boost the inside. At the same time, in the step 5, the internal phase of the adsorption tower 31C is stepped down, and the impurities are further desorbed from the adsorbent in the adsorption tower 31C, and the gas G _{6 is} led out from the gas passage opening 31a side of the adsorption tower 31C. (exhaust gas). This gas G ₆ is discharged from the gas discharge end E3 to the outside of the apparatus via the line 36.

In the steps 1 to 5, the highest pressure inside the adsorption tower 31A in the adsorption step is, for example, 700 to 800 kPa (gage pressure). The pressure inside the adsorption tower 31C at the end of the first cleaning step of the step 1 is, for example, 500 to 600 kPa (gauge pressure) (preferably, based on the internal pressure of the adsorption tower in the depressurization step, the first cleaning is determined. The end of the steps). The pressure (first intermediate pressure) inside the adsorption tower 31C in the end time point of the first decompression step of steps 1 to 2 is, for example, 300 to 400 kPa (gauge pressure). The internal pressure (second intermediate pressure) of the adsorption tower 31C in the end time point of the second decompression step of the step 3 is, for example, 150 to 200 kPa (gauge pressure). The pressure inside the adsorption tower 31C at the end of the first desorption step of the step 4 is, for example, 70 to 100 kPa (gauge pressure). The pressure inside the adsorption tower 31C at the end of the second desorption step of the step 5 is, for example, 0 to 30 kPa (gauge pressure).

In steps 6 to 10, the adsorption step shown in Fig. 9 is performed in the adsorption tower 31B in the same manner as in the adsorption steps 31A in steps 1 to 5. At the same time, in steps 6 to 10, as in the steps 1 to 5 in the adsorption tower 31B, the first cleaning step (step 6) and the second cleaning as shown in Fig. 9 are performed in the adsorption tower 31C. Step (step 7), first boosting step (step 8), and second boosting step (steps 9, 10). At the same time, in steps 6 to 10, the first decompression step (steps 6, 7) shown in Fig. 9 is performed in the adsorption tower 31A in the same manner as in the steps 1 to 5 in the adsorption tower 31C. A second depressurization step (step 8), a first desorption step (step 9), and a second desorption step (step 10).

In steps 11 to 15, the adsorption step shown in Fig. 10 is performed in the adsorption tower 31C in the same manner as in the adsorption steps 31A in steps 1 to 5. At the same time, in steps 11 to 15, the first cleaning step (step 11) and the second cleaning as shown in Fig. 10 are performed in the adsorption tower 31A in the same manner as in the steps 1 to 5 in the adsorption tower 31B. Step (step 12), a first boosting step (step 13), and a second boosting step (steps 14, 15). At the same time, in steps 11 to 15, the first decompression step (steps 11, 12) shown in Fig. 10 is performed in the adsorption tower 31B in the same manner as in the steps 1 to 5 in the adsorption tower 31C. A second depressurization step (step 13), a first desorption step (step 14), and a second desorption step (step 15).

As described above, the argon-enriched refined gas G _{2 is} continuously taken out from the PSA system 3 or the PSA unit 30.

In the above argon gas purification method by the argon gas refining device Y, the adsorption columns 31A, 31B, and 31C are each subjected to the adsorption step, the first pressure reduction step, the second pressure reduction step, and the a desorption step, a second desorption step, a first cleaning step, a second cleaning step, a first pressure increasing step, and a second pressure increasing step, thereby purifying the argon gas in the gas G ₁ as a mixed gas Chemical. The gas G ₁ is temporarily taken into the buffer tank 10 by the above-mentioned raw material gas G ₀ , gas G ₃ ′′, and gas G ₅ , and is moved from the buffer tank 10 to the PSA system 3 or the PSA device 30 for performing the PSA method ( The gas supplied from the adsorption towers 31A, 31B, and 31C) is included. Even if the flow rate, pressure, composition, and the like of the raw material gas G ₀ received in the buffer tank 10 are changed, the raw material gas G _{0 is} temporarily collected. The buffer tank 10 is stored and mixed, and the flow rate fluctuation, the pressure fluctuation, the composition variation, and the like of the gas G ₁ derived from the buffer tank 10 are suppressed. Therefore, by this method, the PSA method is used even when the argon gas is enriched. It is still easy to respond to fluctuations in the flow rate of the material gas G ₀ , pressure fluctuations, composition changes, and the like.

In addition to this, a high yield of the purified gas G ₂ (enriched argon gas) is easily achieved by the present method. The reason is as follows.

First, in the present method, argon gas is continuously introduced from the gas (exhaust gas) continuously derived from the adsorption towers 31A, 31B, and 31C in the above-described desorption step (first desorption step, second desorption step) The relatively high concentration exhaust gas (gas G ₅ ) is introduced into the buffer tank 10, and this exhaust gas is supplied as a re-enrichment of argon gas using the PSA method. The impurities (e.g., carbon dioxide, nitrogen, etc.) adsorbed to the adsorbent in the adsorption step are desorbed from the adsorbent in the desorption step, and in the desorption step, the pressure per unit is lowered as the pressure in the column is lowered. The amount of impurity desorption is increased. Therefore, the impurity content rate of the exhaust gas derived from the adsorption towers 31A, 31B, and 31C in the desorption step tends to gradually increase from the start of the desorption step, and in the present method, the impurity content of the exhaust gas is sufficient. In the low period, the first desorption step of introducing the exhaust gas (gas G ₅ ) into the buffer tank 10 may be performed, and when the impurity content of the exhaust gas is at least a certain value, the exhaust gas (gas G ₆ ) is discharged outside the system. The second desorption step.

Secondly, in the method, among the gases (flushing gas) continuously derived from the adsorption towers 31A, 31B, and 31C in the above-described cleaning steps (the first cleaning step and the second cleaning step), the argon gas concentration is relatively A higher flushing gas (gas G ₃ ") is introduced into the buffer tank 10, and this flushing gas is supplied as an enrichment of argon gas using the PSA method. Since the adsorbent is cleaned as the cleaning step proceeds, The impurity content rate of the rinsing gas derived from the adsorption towers 31A, 31B, and 31C in the cleaning step tends to gradually decrease from the start of the cleaning step. In the present method, the rinsing gas (gas G _{3 ) is performed.} ') The first cleaning step outside the discharge system until the impurity content of the purge gas is sufficiently low, and after the impurity content of the purge gas is sufficiently low, the flushing gas (gas G ₃ ") is introduced into the buffer. A second cleaning step of the tank 10.

As described above, the argon gas refining method according to the present invention is suitable for obtaining high-purity argon gas in a high yield using the PSA method.

In the present method, as described above, the respective pressure reduction steps of the adsorption columns 31A, 31B, and 31C include a first pressure reduction step of deriving the gas G ₃ from the adsorption column during the start of the pressure reduction step, and After the first depressurization step, the second depressurization step of the gas G ₄ is derived from the adsorption column, and the gas G ₃ is introduced as a cleaning gas into the other adsorption column in the cleaning step, and the gas G _{4 is} introduced into the first liter. Other adsorption towers for the pressure step. Since the argon gas concentration of the gas derived from the adsorption towers 31A, 31B, and 31C in the depressurization step is relatively high, the gas derived from the adsorption towers 31A, 31B, and 31C in the depressurization step can be utilized in the other adsorption towers. The cleaning step and the boosting step are performed efficiently. That is, by the present method, the steps performed in the plurality of adsorption columns 31A, 31B, and 31C can be collectively utilized, and the PSA method for enriching argon gas can be efficiently performed.

In the method, the lowest pressure inside the adsorption columns 31A, 31B, and 31C in the desorption step (the first desorption step, the second desorption step) is 0%, and the adsorption column 31A in the adsorption step, In the case where the maximum internal pressure of 31B and 31C is 100%, the first intermediate pressure inside the adsorption towers 31A, 31B, and 31C at the end of the first decompression step is in the range of 35 to 80%, and is in the second subtraction. The second intermediate pressure inside the adsorption towers 31A, 31B, and 31C at the end of the pressing step is smaller than the first intermediate pressure, and the second intermediate pressure is preferably in the range of 15 to 50%. Such conditions are suitable for efficient cleaning and boosting steps.

In the present method, the step of boosting is as described above, and includes introducing the gas G ₄ derived from one of the adsorption columns 31A, 31B, and 31C in the second decompression step into the adsorption towers 31A, 31B, and 31C of the object to be pressurized. A first step of boosting, and a second step of boosting the refined gas G ₂ into the adsorption column after the first step of boosting. Such a two-stage boosting is preferred because the pressure-increasing step and the subsequent adsorption step are efficiently performed in each adsorption column.

In the present method, when the PSA method is carried out, since the inside of the adsorption columns 31A, 31B, and 31C in the desorption step (the first desorption step and the second desorption step) is depressurized, the vacuum pump is not used. Therefore, the lowest pressure inside the adsorption towers 31A, 31B, and 31C is equal to or higher than atmospheric pressure. Such a condition is preferable because the flow rate of the mixed gas from the buffer tank 10 (that is, the load fluctuation of the apparatus) is preferable from the adsorption towers 31A, 31B, 31C or the PSA apparatus for performing the PSA method.

The volume of the buffer tank 10 used in the method is variable as described above. In such a variability, the flow rate of the material gas G ₀ , the gas G ₃ ”, and the gas G ₅ which are collected by the buffer tank 10 in accordance with the buffer tank 10 (in particular, the flow fluctuation of the material gas G ₀ ) and the pressure It is better to change etc.

In the present invention, the flow from the adsorber 31A toward the buffer tank 10, 31B, 31C of the supplied gas G ₁ is, as described above, is updated when the adsorption tower 31A, 31B, 31C of the adsorption step begins. Such an update is preferable because it can reduce the load from the adsorption tower or the PSA apparatus for carrying out the PSA method.

In the present method, as described above, the upper side set amount V _H and the lower side set amount V _{L are} set as described above in the buffer tank 10, and the collected buffer tank 10 is obtained before the gas G ₁ supply flow rate is updated. The average flow rate of the material gas G ₀ is used as the reference flow rate. Therefore, in the present method, when the supply amount of the mixed gas is updated, as described above, when the gas storage amount in the buffer tank 10 is equal to or higher than the upper set amount V _H , the flow rate larger than the reference flow rate is used as the gas G _{1 .} Supply flow rate; the gas storage amount in the buffer tank 10 is lower than the upper side set amount V _H and higher than the lower side set amount V _L , and the reference flow rate is used as the gas G ₁ supply flow rate; the gas storage amount in the buffer tank 10 When the amount is less than or equal to the lower side setting amount V _L , the flow rate is supplied as the gas G ₁ at a flow rate smaller than the reference flow rate. In such a method, when the gas G ₁ supply amount is updated, the gas storage amount in the buffer tank 10 is equal to or higher than the upper side setting amount V _H , and the mixed gas supply flow rate is increased; the gas storage amount in the buffer tank 10 is lower than When the upper side setting amount V _H is higher than the lower side setting amount V _L , the gas G ₁ supply flow rate is not changed, and the gas storage amount in the buffer tank 10 is equal to or lower than the lower side setting amount V _L , and the gas G ₁ supply flow rate is reduced. . According to the above requirements, the buffer tank 10 can change the flow rate of the material gas G ₀ , the gas G ₃ ′′, and the gas G _{5 which} are the intake buffer tank 10 (in particular, the flow rate variation of the material gas G ₀ ), and It is preferable to reduce the load fluctuation of the PSA apparatus or the adsorption towers 31A, 31B, and 31C for performing the PSA method in the pretreatment system 2, and it is preferable to stabilize the load in the pretreatment of the pretreatment system 2. The conversion reaction represented by the reaction formula (1) and the conversion reaction shown in the above reaction formula (2) are all exothermic reactions, and the reduction of the load fluctuation of the pretreatment system 2 and the stabilization of the load are aimed at This exothermic reaction is preferred because it prevents excessive temperature rise and controls the reaction temperature within an appropriate range.

In the present method, the gas supplied to the adsorption tower _{G. 1} 31A, 31B, 31C before, the processing gas G of from 10 applied to the buffer _{tank. 1} before the processing system 2 in the front, the purpose of the pretreatment is to remove or change this gas G At least a portion of the impurities contained in ₁ . Such a configuration is preferable because high-purity argon gas can be obtained.

In the present method, system 2 before processing gas G ₁ to be applied to the front, is divided into a plurality of sections (first to third process) is performed as described above. The conversion reaction shown in the above reaction formula (1) in the first treatment, and the conversion reaction in the above reaction formula (2) in the second and third treatments remove or change at least a part of the impurities contained in the mixed gas. At this time, the pretreatment to be applied to the mixed gas includes a composition in which the pretreatment is divided into a plurality of stages, and in the previous treatment, excessive temperature rise can be prevented and the reaction temperature can be controlled to an appropriate range. It is better inside.

In the present method, then the processing system 2 is supplied in the first gas G ₁ to the adsorption column 31A, 31B, 31C before, by a gas booster 32 G ₁ booster. This boost, since the processing gas G ₁ for the first processing system is applied before the implementation of the PSA process appropriately, it is preferred.

[Examples]

The argon gas purification apparatus Y shown in Figs. 1 to 4 is used to concentrate and separate argon gas from a predetermined source gas G ₀ . The source gas G ₀ in the present embodiment is a used atmosphere gas discharged from a krypton crystal pulling furnace, and contains argon gas as a main component. The specification of the material gas G ₀ is disclosed in the table of Fig. 11.

In the present embodiment, in reserving system 1, the raw material gas G ₀ incorporated into the buffer tank 10, and (3 pretreatment system 2, PSA systems) for supplying the gas G ₁ from 10 toward the rear section of the buffer tank, and for a gas G The flow rate of ₁ is updated when any one of the adsorption towers 31A, 31B, and 31C in the PSA system 3 starts the adsorption step (when the adsorption tower is switched). The flow rate of the gas G ₁ is specifically updated as described below in the above-described method.

First, the average flow rate of one of the adsorption towers 31A, 31B, and 31C at the start of the adsorption step (when the adsorption tower is switched) is determined for the flow rate of the material gas G ₀ measured by the flow meter 13 , as a benchmark traffic. Next, it is converted into a ratio (α%) of the average flow rate (reference flow rate) obtained with respect to the flow rate control range of the flow rate control unit 10 of 0 to 400 Nm ³ /h. Using this ratio (α%), the flow rate to be set next for the gas G _{1 is} calculated. Specifically, in the case where the gas storage amount of the buffer tank 10 measured by the storage amount detector 14 at the time of the adsorption tower switching is the upper setting value of 120 m ³ or more set for the buffer tank 10, 5% is added in α%. On the other hand, the flow rate of (α + 5)% of 0 to 400 Nm ³ /h of the flow rate control range of the flow rate control unit 16 is calculated, and the calculated flow rate is used as the next flow rate of the gas G ₁ . In the case where the gas storage amount of the buffer tank 10 measured by the storage amount detector 14 is less than or equal to 40 m ³ of the lower side set value described above, the flow rate control unit 16 is calculated by subtracting 5% from α%. The flow control range is 0 to 400 Nm ³ /h (α - 5)% of the flow rate, and the calculated flow rate is used as the next flow rate of the gas G ₁ . In the case where the gas storage amount of the buffer tank 10 measured by the storage amount detector 14 at the time of the adsorption tower switching is lower than the upper set value 120 m ³ and higher than the lower set value 40 m ³ , the flow rate control unit is calculated. The flow control range of 16 is 0% to 400 Nm ³ /h of the flow rate of α%, and the calculated flow rate is used as the next flow rate of the gas G ₁ . As for the flow rate of the gas G ₁ is updated, it is maintained until the next adsorption Taqie change so far.

In the present embodiment, the processing system 2 is the front, to the following conditions of the pretreatment gas G _1. A platinum-palladium catalyst was used as a catalyst in the pretreatment tank 20A. With respect to the gas G ₁ before being introduced into the pretreatment tank 20A, the temperature is adjusted to 130 ° C, and a predetermined amount of hydrogen is added so that the hydrogen concentration becomes 0.5 vol% after passing through the pretreatment tanks 20B and 20C in the subsequent stage, and the relative amount is added. The carbon monoxide is a predetermined excess amount of oxygen, so that the carbon monoxide is sufficiently removed in the pretreatment tank 20A. A platinum-based catalyst is used as a catalyst in the pretreatment tank 20B. With respect to the gas G ₁ before being introduced into the pretreatment tank 20B, the temperature is adjusted to 50 ° C, and the hydrogen concentration is limited to 0.5 vol% after passing through the pretreatment tank 20C in the subsequent stage, and a predetermined amount of oxygen is added. The treatment tank 20B removes a part of hydrogen. A platinum-based catalyst is used as a catalyst in the pretreatment tank 20C. With respect to the gas G ₁ before being introduced into the pretreatment tank 20C, the temperature was adjusted to 50 ° C, and a predetermined amount of oxygen was added, and the hydrogen concentration was 0.5 vol% after passing through the pretreatment tank 20C in the subsequent stage. In the cooler 22C after the pretreatment tank 20C, the gas G _{1 is} cooled to 30 to 40 °C.

In the present embodiment, in the PSA system 3 or the PSA device 30, as shown in FIGS. 8 to 10, the adsorption step, the first decompression step, and the second reduction are repeated in the adsorption towers 31A, 31B, and 31C. One cycle consisting of a pressing step, a first desorption step, a second desorption step, a first cleaning step, a second cleaning step, a first step of increasing pressure, and a second step of increasing pressure. The adsorption towers 31A, 31B, and 31C of the PSA apparatus 30 used in the present embodiment each have a cylindrical shape (inner diameter: 800 mm, height: 3,500 mm). In each adsorption column, a predetermined amount of CMS, a predetermined amount of ZMS, and a predetermined amount of alumina are stacked and filled as an adsorbent. Further, in the present embodiment, among the adsorption towers 31A, 31B, and 31C, the adsorption step is performed for 330 seconds, the first depressurization step is performed for 120 seconds, and the second decompression step is performed for 30 seconds, and the first desorption step is performed for 30 seconds. The attaching step is 60 seconds, the second desorption step is 120 seconds, the first cleaning step is 70 seconds, the second cleaning step is 50 seconds, the first step is 30 seconds, and the second step is The step is to perform 180 seconds. The highest pressure inside the adsorption towers 31A, 31B, 31C in the adsorption step is 800 kPa (gauge pressure), and the adsorption towers 10A, 10B in the desorption step (first desorption step, second desorption step), The minimum internal pressure of 10C is atmospheric pressure. Further, the internal pressure (first intermediate pressure) of the adsorption towers 31A, 31B, and 31C in the end time point of the first depressurization step is 400 kPa (gauge pressure), and is at the end time point of the second decompression step. The internal pressure (second intermediate pressure) of the adsorption towers 31A, 31B, and 31C is 200 kPa (gauge pressure).

The purified gas G ₂ obtained in the present example subjected to such a condition had an argon purity of 99.5 vol%, a hydrogen concentration of 0.5 vol%, and an argon recovery rate of about 70%. The specifications of the obtained purified gas G ₂ are disclosed in the table of Fig. 11.

1. . . Storage system

2. . . Pretreatment system

3. . . PSA system

4. . . Recycling line

4a. . . Automatic valve

10. . . Storage tank

11. . . dust collector

12. . . Booster blower

13. . . Flow meter

14. . . Storage meter

15. . . Concentration analyzer

16. . . Flow control department

17. . . line

20A. . . Pretreatment tank

20a. . . Entrance end

20B. . . Pretreatment tank

20b. . . Exit end

20C. . . Pretreatment tank

twenty one. . . Preheater

22A. . . Cooler

22B. . . Cooler

22C. . . Cooler

twenty three. . . Hydrogen supply control department

24A. . . Hydrogen supply control department

24B. . . Oxygen supply control department

24C. . . Oxygen supply control department

25A. . . thermometer

25B. . . thermometer

25C. . . thermometer

26A. . . Flow control department

26B. . . Flow control department

27. . . Hydrogen concentration analyzer

28A. . . line

28B. . . line

28b. . . Bypass line

28C. . . line

28c. . . Bypass line

28D. . . line

30. . . PSA device

31A. . . Adsorption tower

31a. . . Gas passage

31B. . . Adsorption tower

31b. . . Gas passage

31C. . . Adsorption tower

32. . . Booster

32a. . . Gas suction

32b. . . Gas outlet

33. . . line

33’. . . Main road

33A. . . Branch road

33a. . . Automatic valve

33B. . . Branch road

33b. . . Automatic valve

33C. . . Branch road

33c. . . Automatic valve

34. . . line

34’. . . Main road

34A. . . Branch road

34a. . . Automatic valve

34B. . . Branch road

34b. . . Automatic valve

34C. . . Branch road

34c. . . Automatic valve

35. . . line

35’. . . Main road

35A. . . Branch road

35a. . . Automatic valve

35B. . . Branch road

35b. . . Automatic valve

35C. . . Branch road

35c. . . Automatic valve

36. . . line

36’. . . Main road

36A. . . Branch road

36a. . . Automatic valve

36B. . . Branch road

36b. . . Automatic valve

36C. . . Branch road

36c. . . Automatic valve

36d. . . Automatic valve

E1. . . Raw material gas introduction end

E2. . . Refined gas outlet

E3. . . Gas discharge end

G0. . . Raw material gas

G1. . . gas

G2. . . Refined gas

G3. . . gas

G3’. . . gas

G3"...gas

G4. . . gas

G5. . . gas

G6. . . gas

V _H . . . Upper set value

V _L . . . Lower set value

Y. . . Argon refining device

Fig. 1 is a view showing the overall schematic configuration of an argon gas purifying apparatus according to the present invention.

Fig. 2 is a view showing the configuration of a storage system of an argon gas purifying apparatus which is a part of the argon gas purifying apparatus shown in Fig. 1.

Fig. 3 is a view showing the configuration of a pretreatment system of an argon gas purifying apparatus which is a part of the argon gas purifying apparatus shown in Fig. 1.

Fig. 4 is a view showing the configuration of a PSA system of an argon gas purifying apparatus which is a part of the argon gas purifying apparatus shown in Fig. 1.

Fig. 5 is a table showing the steps performed in the adsorption towers of steps 1 to 5 of the PSA method for carrying out the PSA apparatus shown in Fig. 4, and the automatic valves of the PSA apparatus shown in Fig. 4; And the opening and closing state of the automatic valve of the recovery line.

Fig. 6 is a table showing the steps performed in the adsorption towers of steps 6 to 10 of the PSA method for carrying out the PSA apparatus shown in Fig. 4, and the automatic valves of the PSA apparatus shown in Fig. 4; And the opening and closing state of the automatic valve of the recovery line.

Figure 7 is a table showing the steps performed in the adsorption towers of steps 11 to 15 of the PSA method for carrying out the PSA apparatus shown in Fig. 4, and the automatic valves of the PSA apparatus shown in Fig. 4. And the opening and closing state of the automatic valve of the recovery line.

Fig. 8 (a) to (e) show gas flow states in steps 1 to 5 of the PSA method for carrying out the PSA apparatus shown in Fig. 4.

Fig. 9 (a) to (e) show gas flow states in steps 6 to 10 of the PSA method for carrying out the PSA apparatus shown in Fig. 4.

Fig. 10 (a) to (e) show gas flow states in steps 11 to 15 of the PSA method for carrying out the PSA apparatus shown in Fig. 4.

Fig. 11 is a table showing the specifications of the material gas and the refined gas in the examples.

1. . . Storage system

2. . . Pretreatment system

3. . . PSA system

4. . . Recycling line

10. . . Storage tank

11. . . dust collector

12. . . Booster blower

13. . . Flow meter

14. . . Storage meter

15. . . Concentration analyzer

16. . . Flow control department

17. . . line

20A. . . Pretreatment tank

20B. . . Pretreatment tank

20C. . . Pretreatment tank

twenty one. . . Preheater

22A. . . Cooler

22B. . . Cooler

22C. . . Cooler

twenty three. . . Hydrogen supply control department

24A. . . Hydrogen supply control department

24B. . . Oxygen supply control department

24C. . . Oxygen supply control department

25A. . . thermometer

25B. . . thermometer

25C. . . thermometer

26A. . . Flow control department

26B. . . Flow control department

27. . . Hydrogen concentration analyzer

28A. . . line

28B. . . line

28b. . . Bypass line

28C. . . line

28c. . . Bypass line

28D. . . line

31A. . . Adsorption tower

31B. . . Adsorption tower

31C. . . Adsorption tower

32. . . Booster

33. . . line

34. . . line

35. . . line

36. . . line

E1. . . Raw material gas introduction end

G0. . . Raw material gas

G1. . . gas

G2. . . Refined gas

G3’. . . gas

G3"...gas

G5. . . gas

G6. . . gas

Y. . . Argon refining device

Claims (18)

An argon gas refining method comprising: charging a mixed gas containing argon gas into a storage tank; supplying the mixed gas from the storage tank to a selected adsorption tower in a plurality of adsorption towers filled with the adsorbent; In each of the adsorption towers, a cycle comprising the following steps is repeated: an adsorption step, wherein the mixed gas is introduced into the adsorption tower while the adsorption tower is at a relatively high pressure, and the adsorbent is adsorbed in the mixed gas. Impure, and argon-enriched refined gas is withdrawn from the adsorption tower; in a depressurization step, the adsorption tower is depressurized and the gas is led out from the adsorption tower; a desorption step is performed to depressurize the adsorption tower from the The adsorbent desorbs the above impurities, and derives a gas from the adsorption tower; a cleaning step of introducing a cleaning gas into the adsorption tower and deriving a gas from the adsorption tower; and a step of increasing the pressure in the adsorption tower; wherein the cleaning step The cleaning gas is a gas derived from the adsorption column in the depressurization step; and the cleaning step includes deriving the first from the adsorption column in the cleaning step a first cleaning step of discharging the gas to the outside, a second cleaning step after the first cleaning step of deriving the second exhaust gas from the adsorption tower in the cleaning step, and introducing the second exhaust gas into the storage tank . An argon gas refining method as described in claim 1, wherein The desorption step includes a first desorption step of introducing the first desorbed gas from the adsorption column in the desorption step into the storage tank, and an adsorption column from the desorption step after the first desorption step A second desorption step of deriving the second desorbed gas and discharging it to the outside. The argon gas refining method according to claim 2, wherein the depressurizing step comprises deriving a first decompressed gas from the adsorption tower in the depressurizing step as the cleaning gas to be introduced into the adsorption tower in the cleaning step. The first depressurization step and the second decompressing gas are taken out from the adsorption column in the depressurization step after the first depressurization step, and introduced into the adsorption column in the step of increasing the pressure. The argon gas refining method according to claim 3, wherein the lowest pressure inside the adsorption column in the desorption step is 0%, and the highest pressure in the interior of the adsorption column in the adsorption step is 100. In the case of %, the first intermediate pressure inside the adsorption tower at the end of the first depressurization step is in the range of 35 to 80%, and the second inside of the adsorption tower at the end of the second decompression step The intermediate pressure is less than the limit of the first intermediate pressure, and the second intermediate pressure is in the range of 15 to 50%. The argon gas refining method according to claim 4, wherein the step of boosting comprises first introducing a second decompressed gas derived from the adsorption tower in the second decompression step into an adsorption tower of a pressure-boosting target The step of boosting and the second step of boosting the refined gas into the adsorption column after the first step of boosting. The argon gas refining method according to any one of claims 1 to 5, wherein a minimum pressure inside the adsorption tower in the desorption step is large Above the air pressure. The argon gas purification method according to any one of claims 1 to 5, wherein a flow rate of the mixed gas supplied from the storage tank toward the adsorption tower is updated when the adsorption tower starts the adsorption step . The argon gas refining method according to claim 7, wherein: the upper side setting amount and the lower side setting amount smaller than the upper side setting amount are set with respect to the storage amount in the storage tank; and the supply flow rate of the mixed gas is updated. When the storage amount of the mixed gas in the storage tank is equal to or greater than the upper side setting amount, increasing the mixed gas supply flow rate; the storage amount of the mixed gas in the storage tank is lower than the upper side setting amount and higher than the In the case of the lower side setting amount, the mixed gas supply flow rate is not changed; and the storage amount of the mixed gas in the storage tank is equal to or less than the lower side set amount, and the mixed gas supply flow rate is reduced. The argon gas refining method according to claim 7, wherein: the upper side setting amount and the lower side setting amount smaller than the upper side setting amount are set with respect to the storage amount in the storage tank; when the mixed gas supply flow rate is updated Previously, the flow rate of the mixed gas collected in the storage tank is obtained as a reference flow rate; and when the supply flow rate of the mixed gas is updated, the storage amount of the mixed gas in the storage tank is equal to or greater than the upper set amount. The flow rate greater than the reference flow rate is the mixed gas supply flow rate; the storage amount of the mixed gas in the storage tank is lower than the upper side setting When the amount is higher than the lower side setting amount, the reference flow rate is the mixed gas supply flow rate; and the storage amount of the mixed gas in the storage tank is equal to or less than the lower side set amount, and is smaller than the reference flow rate. The flow rate is the mixed gas supply flow. The argon gas refining method according to any one of claims 1 to 5, wherein, before the mixed gas is supplied to the adsorption tower, the mixed gas is pretreated from the storage tank, and the purpose of the pretreatment is It is to remove or change at least a part of the impurities contained in the mixed gas. The argon gas refining method according to claim 10, wherein the pretreatment is carried out in a plurality of stages. The argon gas refining method according to claim 11, wherein the mixed gas contains at least carbon monoxide and hydrogen in addition to argon; the pretreatment comprises a first treatment for reacting carbon monoxide with oxygen to generate carbon dioxide. And a second treatment of reacting hydrogen with oxygen to generate water after the first treatment. An argon gas refining device comprising: an adsorption tower having a first gas passage opening and a second gas passage opening, wherein the first and second gas passage openings are filled with an adsorbent; and a storage tank is used Preserving the mixed gas before supplying the mixed gas containing argon gas to the adsorption tower; a first line connecting the storage tank and the adsorption tower to supply the mixed gas from the storage tank to the The first gas of the adsorption tower passes through the mouth side; a second line connecting the first gas passage opening side of the adsorption tower and having an exhaust end; and a third line connecting the second line and the storage tank. An argon gas refining device comprising: a plurality of adsorption towers having a first gas passage opening and a second gas passage opening, wherein the first and second gas passage openings are filled with an adsorbent; a storage tank, And a first line connecting the storage tank and the adsorption towers to obtain the mixed gas from the storage tank before supplying the mixed gas containing argon gas to the adsorption towers; The first gas supplied to each adsorption tower passes through the port side; a second line includes a main road having an exhaust end, and the first gas passage port provided in each of the adsorption towers to connect the adsorption towers a plurality of branch roads on the side; a third line comprising a trunk road, and a plurality of branch roads disposed on each of the adsorption towers connected to the second gas passage side of each of the adsorption towers; and a fourth line The second line and the storage tank are connected. The argon gas refining device according to claim 14, further comprising: means for detecting the storage amount in the storage tank, means for detecting the flow rate of the mixed gas supplied to the storage tank, and for controlling A device for the flow rate of the mixed gas supplied from the storage tank toward the adsorption towers. An argon gas refining device according to claim 14 or 15, wherein a pretreatment system for performing a pretreatment is provided at the first The purpose of the pretreatment is to remove or change at least a portion of the impurities contained in the mixed gas. The argon gas refining apparatus of claim 16, wherein the pretreatment system comprises a plurality of processing tanks for dividing the pretreatment into a plurality of stages. The argon gas refining device according to claim 17, wherein the mixed gas contains at least carbon monoxide and hydrogen in addition to the argon gas; the pretreatment system comprises a first treatment tank and a second treatment tank. The first treatment tank is for performing a first treatment for reacting carbon monoxide with oxygen to generate carbon dioxide, and the second treatment tank is for performing a second treatment of reacting hydrogen with oxygen to generate water after the first treatment.