JP5846641B2 - Helium gas purification method and purification apparatus - Google Patents

Description

  The present invention relates to a method and apparatus suitable for purifying helium gas containing at least hydrogen, carbon monoxide, nitrogen and oxygen as impurities, such as helium gas recovered after use in an optical fiber manufacturing process. .

  For example, there is a case where helium gas used in the optical fiber drawing process and diffused into the atmosphere after use is recovered and reused. Such recovered helium gas is refined because it contains impurities such as hydrogen, carbon monoxide, and air-derived nitrogen, oxygen, etc. that are mixed by being released into the atmosphere after use. It is necessary to increase the purity.

  Therefore, a method is known in which impurities contained in the helium gas before purification are liquefied and removed by a deep cooling operation using liquid nitrogen as a cold heat source, and remaining trace impurities are adsorbed and removed by an adsorbent (Patent Document 1). reference). In addition, hydrogen is added to the helium gas before purification, and the hydrogen is reacted with oxygen as an air component as an impurity to generate moisture. After removing the moisture, the remaining impurities are removed by the membrane separation means. A method is known (see Patent Document 2). Furthermore, a method is known in which impurities contained in a rare gas such as helium before purification are removed by contacting with an alloy getter (see Patent Document 3). Furthermore, hydrogen is added to the helium gas before purification, then water is generated by the first reaction between oxygen and hydrogen in the helium gas, and then the moisture content of the helium gas is reduced by dehydration operation. In addition, the oxygen molar concentration in the helium gas is set to a value exceeding 1/2 of the sum of the carbon monoxide molar concentration and the hydrogen molar concentration by adding oxygen as necessary, and then in the helium gas. Carbon dioxide and water are produced by a second reaction in which oxygen is reacted with carbon monoxide and hydrogen, and then oxygen, nitrogen, carbon dioxide and water in helium gas are adsorbed by pressure swing adsorption method and thermal swing adsorption method. It is known to perform an adsorption process for adsorbing to a liquid (see Patent Document 4).

Japanese Patent Laid-Open No. 10-31174 JP 2003-246611 A JP-A-4-209710 JP 2012-31049 A

  In the method described in Patent Document 1, since a deep cooling operation with liquid nitrogen is necessary, the cooling energy is increased and the merit of recovering helium gas is reduced.

  In the method described in Patent Document 2, since a membrane separation module is required, the equipment cost is increased, and the merit of recovering helium gas is reduced. Further, in the method described in Patent Document 2, oxygen is removed by adding hydrogen to the helium gas to be purified, but sufficient removal of hydrogen is not taken into consideration, and deterioration is caused by hydrogen such as an optical fiber material. There is a risk of adversely affecting the material on which the material travels.

  In the method described in Patent Document 3, since the ability of the alloy getter is small, it can be used only when ultra-high purity helium gas having an impurity concentration of the ppm order is low, and many impurities are mixed. If not available directly.

  In the method described in Patent Document 4, if the amount of oxygen in the helium gas after hydrogenation is too small than the stoichiometric amount necessary to react with all of hydrogen, a large amount of carbon monoxide reacts with oxygen. Without remaining in helium gas. In this case, since carbon monoxide is toxic, it becomes difficult to handle helium gas until it is combined with oxygen by the second reaction. On the other hand, if the amount of oxygen in the helium gas after hydrogen addition becomes too much than the stoichiometric amount necessary for reacting with all of hydrogen and carbon monoxide, the oxygen remaining in the helium gas even after the second reaction. The amount increases, and the oxygen adsorption load in the subsequent adsorption step increases. Therefore, in order to set the hydrogen addition amount before the first reaction and the oxygen addition amount before the second reaction to appropriate values, it is necessary to analyze the helium gas and add oxygen and hydrogen before each reaction. This makes the refining operation complicated.

  Further, in the method described in Patent Document 4, a dehydration operation is performed between the first reaction and the second reaction. Then, each reaction is usually performed at about 250 ° C., while the dehydration operation is usually performed after cooling the helium gas to room temperature. Therefore, the helium gas heated in the first reaction needs to be once cooled for the dehydration operation and then heated again for the second reaction, which increases energy consumption. Further, in order to continuously supply and process helium gas to be purified, a reaction vessel having a reaction region for executing the first reaction and a reaction vessel having a reaction region for executing the second reaction Are separately provided, and a dehydrator is required between both reaction vessels, which increases the size of the equipment and increases the cost.

  An object of the present invention is to provide a method and apparatus for purifying helium gas that can solve the above-described problems of the prior art.

The method of the present invention contains at least hydrogen, carbon monoxide, nitrogen, and oxygen as impurities, and the amount of oxygen initially contained is the chemistry required to react with all of the initially contained hydrogen and carbon monoxide. When purifying a helium gas larger than the stoichiometric amount, a first reaction step of reacting hydrogen and carbon monoxide originally contained in the helium gas with oxygen contained from the beginning using a catalyst; and A hydrogen addition step of adding less than the stoichiometric amount of hydrogen necessary to react with all of the oxygen remaining in the helium gas by performing one reaction step; and a step of performing the first reaction step. A second reaction step in which oxygen remaining in the helium gas is reacted with hydrogen added in the hydrogen addition step using a catalyst; and the helium after the second reaction step is performed. A dehydration step for reducing the moisture content of the sulfur gas by a dehydration operation, and a pressure swing adsorption step for adsorbing at least carbon dioxide, nitrogen and oxygen remaining in the helium gas after the dehydration operation to an adsorbent by a pressure swing adsorption method; It is characterized by providing.
In the helium gas purified by the present invention, the amount of oxygen initially contained is greater than the stoichiometric amount necessary to react with all of the initially contained hydrogen and carbon monoxide. Therefore, hydrogen and carbon monoxide initially contained in the helium gas and part of the oxygen initially contained can be converted into water and carbon dioxide by the first reaction step. The oxygen remaining in the helium gas by the execution of the first reaction step and the hydrogen added in the hydrogen addition step can be converted to water by the second reaction step. Since the amount of hydrogen added is less than the stoichiometric amount necessary to react with all of the oxygen remaining in the helium gas by performing the first reaction step, hydrogen is added to the helium gas after performing the second reaction step. Can be prevented from remaining. As a result, the analysis of the impurity concentration of helium gas and the gas addition are not performed before the first reaction step, but only before the second reaction step, so that a large amount of carbon monoxide remains after the first reaction step. Since it is prevented and a large amount of oxygen remains before the adsorption step, the purification operation can be simplified. Also, hydrogen, which is difficult to separate from helium gas depending on the adsorption method, can be removed from helium gas before the adsorption step. By removing the water generated in the second reaction step from the helium gas by a dehydration operation, the moisture content of the helium gas is reduced, so that the moisture adsorption load in the subsequent adsorption step can be reduced.

  The amount of hydrogen added in the hydrogen addition step is 95% or more and less than 100% of the stoichiometric amount necessary for reacting with all of the oxygen remaining in the helium gas by the execution of the first reaction step. preferable. Thus, most of the oxygen in the helium gas is allowed to react with hydrogen in the second reaction step, and in the adsorption step, it is sufficient to adsorb a slight amount of oxygen remaining in the helium gas.

  The dehydration step is preferably performed by cooling the helium gas after the second reaction step. According to the present invention, since the dehydration operation is performed after the second reaction step, it is not necessary to reheat the helium gas once cooled for the dehydration operation, and the energy consumption can be reduced.

  Preferably, activated alumina, zeolite-based adsorbent, and carbon molecular sieve are used as the adsorbent, and after adsorbing carbon dioxide on activated alumina, nitrogen is adsorbed on the zeolite-based adsorbent. Since the activated alumina adsorbs carbon dioxide, it is possible to prevent a decrease in the nitrogen adsorption effect by the zeolite-based adsorbent and to effectively remove nitrogen from the helium gas.

  After the pressure swing adsorption step, it is preferable to provide a thermal swing adsorption step in which nitrogen and oxygen remaining in the helium gas are adsorbed on the adsorbent by a thermal swing adsorption method at −10 ° C. to −50 ° C. Thereby, the content rate of nitrogen and oxygen in helium gas can further be reduced.

The apparatus of the present invention contains at least hydrogen, carbon monoxide, nitrogen and oxygen as impurities, and the amount of oxygen initially contained is the chemistry necessary to react with all of the initially contained hydrogen and carbon monoxide. An apparatus for purifying helium gas larger than a stoichiometric amount, a heater for heating the helium gas, a first reaction region filled with a catalyst for reacting hydrogen and carbon monoxide with oxygen, hydrogen A reaction apparatus having a second reaction region filled with a catalyst for reacting oxygen with oxygen, a connection region between the first reaction region and the second reaction region, a hydrogen supply source, and an oxygen concentration of helium gas A hydrogen adding device having a hydrogen amount adjusting device for adjusting the amount of hydrogen supplied from the hydrogen supply source according to the determined oxygen concentration, a dehydrating device, and an adsorption device connected to the dehydrating device And with . The reaction apparatus has a gas inlet connected to the heater, a gas outlet connected to the dehydrator, a gas extraction port connected to the analyzer, and the amount of hydrogen adjusted to the hydrogen supply source And a hydrogen addition port connected through a vessel. The gas introduction so that the helium gas introduced from the gas introduction port into the reaction apparatus flows out from the gas outlet after sequentially passing through the first reaction region, the connection region, and the second reaction region. A mouth, the first reaction region, the connection region, the second reaction region, and the gas outlet are disposed. The gas extraction port is disposed at a position where helium gas can be extracted in the connection region, and the hydrogen addition port can add hydrogen to the helium gas introduced into the second reaction region after passing through the first reaction region. Placed in position. The amount of hydrogen added to the helium gas from the hydrogen addition port is less than the stoichiometric amount necessary to react with all of the oxygen remaining in the helium gas by the reaction in the first reaction region. The amount of hydrogen supplied from the hydrogen supply source is adjusted by the hydrogen amount adjuster according to the oxygen concentration of the helium gas in the connection region determined by the analyzer. The dehydrator is connected to the gas outlet so that the moisture content of the helium gas flowing out from the gas outlet is reduced by the dehydration operation. The adsorption device includes a pressure swing adsorption unit that adsorbs at least carbon dioxide, nitrogen and oxygen in the helium gas to an adsorbent by a pressure swing adsorption method.
According to the apparatus of the present invention, the method of the present invention can be implemented.

  In the apparatus of the present invention, it is preferable that the reaction apparatus has a single reaction vessel, and the first reaction region, the connection region, and the second reaction region are provided in the reaction vessel. Thereby, a 1st reaction process and a 2nd reaction process can be performed in a single reaction container, an installation can be made compact and cost can be reduced.

  According to the present invention, a practical method capable of purifying helium gas with high purity by effectively and efficiently reducing the impurity content in helium gas without requiring a large amount of purification energy with low-cost and compact equipment. And equipment can be provided.

Structure explanatory drawing of the refiner | purifier of helium gas which concerns on embodiment of this invention Structure explanatory drawing of the pressure swing adsorption | suction unit in the refiner | purifier of helium gas which concerns on embodiment of this invention Structure explanatory drawing of the thermal swing adsorption | suction unit in the refiner | purifier of helium gas which concerns on embodiment of this invention The figure which shows the modification of the reaction apparatus in the refiner | purifier of helium gas which concerns on embodiment of this invention

  A helium gas purification apparatus α shown in FIG. 1 is for purifying helium gas supplied from a supply source 1, and includes a heater 2, a reaction apparatus 3, a hydrogenation apparatus 4, a dehydration apparatus 5, and an adsorption apparatus 9. Is provided.

The to-be-purified helium gas continuously supplied from the supply source 1 is removed by a filter (not shown) and introduced into the heater 2 through a gas feed means 6 such as a blower. The helium gas to be purified contains at least hydrogen (H ₂ ), carbon monoxide (CO), nitrogen (N ₂ ), and oxygen (O ₂ ) as impurities in addition to helium (He). A trace amount of impurities may be contained. The concentration of impurities initially contained in the helium gas to be purified is preferably 1 vol% to 50 vol%.

  If the helium gas to be purified is, for example, recovered from the helium gas released into the atmosphere after use in the optical fiber drawing process, oxygen and nitrogen, which are impurities derived from the air, are larger than other impurities. Contained. In this case, the air concentration in the helium gas to be purified is 10 to 50 mol% and is usually 20 to 40 mol%, and the hydrogen concentration and the carbon monoxide concentration are each about several tens mol ppm. Thus, the amount of oxygen initially contained in the helium gas to be purified is greater than the stoichiometric amount required to react with all of the initially contained hydrogen and carbon monoxide. That is, the molar concentration of oxygen initially contained exceeds 1/2 of the sum of the molar concentration of hydrogen initially contained and the molar concentration of carbon monoxide. Hydrogen and carbon monoxide contained as impurities in the helium gas to be purified include those contained in minute amounts in air, but are not mainly derived from air but are mixed in the environment in which helium gas is used. For example, when helium gas that has been released into the atmosphere after use in an optical fiber drawing process is recovered, the air other than hydrogen and carbon monoxide mixed in the drawing process and nitrogen and oxygen derived from the air mixed in the recovery process. The helium gas to be purified contains a negligible amount of impurities such as carbon dioxide and hydrocarbons derived from it. The helium gas to be purified contains argon (Ar) when mixed with air, but the argon content in the air is lower than that of oxygen and nitrogen. Argon can be ignored without being regarded as an impurity because it can be replaced with argon when utilizing the characteristics as an inert gas.

  The helium gas to be purified is heated by the heater 2 and then introduced into the reaction apparatus 3. The heating temperature of the helium gas by the heater 2 is preferably set so that the reaction temperature in the reaction device 3 is 150 ° C. or higher when ruthenium (Ru) is used as a catalyst in the reaction device 3 in order to complete the reaction. On the other hand, it is preferable to set the reaction temperature to be 250 ° C. or lower from the viewpoint of preventing shortening of the catalyst life, and from the viewpoint of reducing energy consumption, the reaction temperature is set to be 200 ° C. or lower. More preferred. When a catalyst containing palladium (Pd) is used in the reactor 3, it is preferable to set the heating temperature of the helium gas so that the reaction temperature in the reactor 3 is 200 ° C to 300 ° C.

  The reaction apparatus 3 of this embodiment has a single tower-shaped reaction vessel 3a, and a first reaction region 3A, a second reaction region 3B, and a connection region 3C are provided inside the reaction vessel 3a. The first reaction zone 3A is filled with a catalyst for reacting hydrogen and carbon monoxide with oxygen. The second reaction zone 3B is filled with a catalyst for reacting hydrogen with oxygen. The catalysts filled in the reaction regions 3A and 3B may be different from each other, but the same catalyst is filled in this embodiment. For example, it is preferable that both reaction regions 3A and 3B are filled with a noble metal catalyst such as ruthenium, palladium, or platinum, particularly a ruthenium catalyst that can react at a low temperature. A catalyst supported on alumina or the like is used. A connection region 3C is defined between the first reaction region 3A and the second reaction region 3B. Although it is not necessary to fill the connection area 3C with a catalyst, in the present embodiment, the same catalyst as that filled in both the reaction areas 3A and 3B is filled in the connection area 3C.

  The reaction vessel 3a is provided with a gas inlet 3b, a gas outlet 3c, a gas extraction port 3d, and a hydrogen addition port 3e. The heater 2 is connected to the gas inlet 3b, and the heated helium gas to be purified is introduced into the reactor 3 from the gas inlet 3b. A gas inlet 3b, a first reaction region 3A, a connection region 3C, a second reaction region 3B, and a gas outlet 3c are arranged in this order from one end of the reaction vessel 3a, and the gas outlet 3c is located at the other end of the reaction vessel 3a. To do. For example, the connection region 3C is arranged near the center between the gas inlet 3b and the gas outlet 3c. As a result, the helium gas introduced into the reaction device 3 from the gas inlet 3b flows out of the gas outlet 3c after passing through the first reaction region 3A, the connection region 3C, and the second reaction region 3B in this order. The gas extraction port 3d is disposed at a position where helium gas can be extracted in the connection region 3C, and is disposed so as to communicate with the connection region 3C in the present embodiment. The hydrogen addition port 3e is disposed at a position where hydrogen can be added to the helium gas introduced into the second reaction region 3B after passing through the first reaction region 3A. In this embodiment, the second reaction region 3B and the connection region 3C It arrange | positions so that it may lead to the boundary vicinity.

  The helium gas heated by the heater 2 reaches the first reaction region 3A from the gas inlet 3b. Thereby, the 1st reaction process which makes hydrogen and carbon monoxide contained from the beginning in helium gas react with oxygen contained from the beginning using a catalyst is performed. At this time, it is not necessary to add impurities other than impurities originally contained in the helium gas reaching the first reaction region 3A. By the first reaction step, hydrogen and carbon monoxide originally contained in the helium gas and a part of oxygen contained from the beginning are converted into water and carbon dioxide. Even when the first reaction step is executed, oxygen remains in the helium gas. Therefore, main impurities contained in the helium gas by the first reaction step are nitrogen, oxygen, carbon dioxide, and water.

  The hydrogen addition device 4 is connected to the reaction device 3 through a gas extraction port 3d and a hydrogen addition port 3e. That is, the hydrogen adding device 4 is supplied from the hydrogen supply source 4a according to the hydrogen supply source 4a configured by, for example, a high-pressure hydrogen cylinder, the analyzer 4b for obtaining the oxygen concentration of the helium gas, and the oxygen concentration obtained by the analyzer 4b. A hydrogen amount adjuster 4c for adjusting the amount of hydrogen produced. The analyzer 4b is connected to the gas extraction port 3d, and obtains the oxygen concentration of helium gas in the connection region 3C extracted from the gas extraction port 3d. The hydrogen supply source 4a is connected to the hydrogen addition port 3e via the hydrogen amount regulator 4c. The hydrogen amount adjuster 4c adjusts the amount of hydrogen supplied from the hydrogen supply source 4a by, for example, adjusting the opening of a pipe connecting the hydrogen supply source 4a and the hydrogen addition port 3e with a flow control valve or the like. It adjusts according to the oxygen concentration calculated | required by. By this preparation, the amount of hydrogen added to the helium gas from the hydrogen addition port 3e is made less than the stoichiometric amount necessary for reacting with all of the oxygen remaining in the helium gas by the reaction in the first reaction region 3A. The As a result, a hydrogen addition step of adding less than the stoichiometric amount of hydrogen necessary to react with all of the oxygen remaining in the helium gas by the execution of the first reaction step to the helium gas is executed. The In the present embodiment, the amount of hydrogen added to the helium gas in the hydrogen addition step is 95% or more and 100% of the stoichiometric amount necessary to react with all of the oxygen remaining in the helium gas by the execution of the first reaction step. Less than. That is, by this hydrogenation, the hydrogen molar concentration in helium gas is set to 1.9 times or more and less than 2 times the oxygen molar concentration.

  In the second reaction region 3B, a second reaction step is performed in which oxygen remaining in the helium gas by the execution of the first reaction step is reacted with hydrogen added in the hydrogen addition step using a catalyst, and the reacted oxygen and Hydrogen is transformed into water. The main impurities contained in the helium gas by the execution of the second reaction step are nitrogen, oxygen, carbon dioxide, and water as in the case of the execution of the first reaction step, but the oxygen content decreases. Note that the size of the first reaction region 3A may be determined experimentally so that hydrogen and carbon monoxide can sufficiently react with oxygen in the first reaction step. The size of the second reaction region 3B may be determined experimentally so that the hydrogen added from the hydrogen addition port 3e can be sufficiently reacted with oxygen by the second reaction step. The size of the connection region 3C is such that helium gas after the execution of the first reaction step can be extracted for analysis, and hydrogen added from the hydrogen addition port 3e does not reach the first reaction region 3A. In addition, it may be determined experimentally.

  In this embodiment, the dehydrating device 5 includes a first dehydrating device 5a and a second dehydrating device 5b connected to the first dehydrating device 5a. The first dehydrator 5a is connected to the gas outlet 3c of the reactor 3. A dehydration step is performed by the first dehydrator 5a to reduce the moisture content of the helium gas after the second reaction step that flows out from the gas outlet 3c by a dehydration operation. The first dehydrator 5a of the present embodiment performs the dehydration step by cooling the helium gas after the second reaction. That is, since the temperature of the helium gas flowing out from the gas outlet 3c is usually 200 ° C. to 350 ° C., it is cooled to about room temperature, for example, 0 ° C. to 40 ° C. with a cooler or the like, and the condensed water is Discharge out of the system with a separator. Note that part of the carbon dioxide contained in the helium gas is dissolved in the condensed water and can be removed from the helium gas by a dehydration operation.

  The first dehydrator 5a can reduce the amount of water in the helium gas to the amount of saturated water vapor at the temperature after cooling. The second dehydrator 5b reduces the amount of water in the helium gas to less than the saturated water vapor amount at that temperature, and can be constituted by, for example, a heat regeneration dehydrator, a pressure dehydrator, or a refrigeration dehydrator. The second dehydrator 5b can reduce the moisture content of the helium gas to less than several hundred ppm. The configuration of the dehydrating device 5 is not limited as long as the moisture content of the helium gas can be reduced. For example, the dehydrating device 5 may include only one of the first and second dehydrating devices 5a and 5b. Since the adsorption step is usually performed at room temperature, it is preferable to dehydrate by cooling the helium gas. Further, since the adsorbent such as activated alumina used in the pressure swing adsorption process preferentially adsorbs moisture, the moisture content of the helium gas is reduced as much as possible by the dehydrator 5, and the adsorbent such as activated alumina is reduced. It is preferable to prevent a decrease in carbon dioxide adsorption performance, and therefore it is preferable to include the first and second dehydrators 5a and 5b.

  The adsorption device 9 is connected to the dehydration device 5 and has a PSA unit (pressure swing adsorption unit) 10 connected to the second dehydration device 5 b and a TSA unit (thermal swing adsorption unit) 20 connected to the PSA unit 10. After the dehydration operation by the dehydrator 5, the PSA unit 10 executes a pressure swing adsorption process in which at least carbon dioxide, nitrogen and oxygen remaining in the helium gas are adsorbed on the adsorbent by the pressure swing adsorption method. Furthermore, the PSA unit 10 also adsorbs moisture remaining in the helium gas after the dehydration operation by the dehydrator 5. The PSA unit 10 can reduce the content of carbon dioxide and water in the helium gas to, for example, less than 1 mol ppm, and reduce the nitrogen content and the oxygen content to, for example, about 1 mol ppm. After the pressure swing adsorption process, the TSA unit 20 executes a thermal swing adsorption process in which nitrogen remaining in the helium gas is adsorbed to the adsorbent by a thermal swing adsorption method at −10 ° C. to −50 ° C. Furthermore, the TSA unit 20 also adsorbs oxygen remaining in the helium gas after the pressure swing adsorption process. The TSA unit 20 can reduce the nitrogen content and the oxygen content in the helium gas to, for example, less than 1 mol ppm.

  As the PSA unit 10, a known unit can be used. For example, the PSA unit 10 shown in FIG. 2 is a four-column type, and has a compressor 12 for compressing helium gas flowing out from the dehydrator 5 and four first to fourth adsorption towers 13. Adsorbent is filled. As the adsorbent, those suitable for adsorption of carbon dioxide, nitrogen, and oxygen are used. For example, activated alumina, zeolite-based adsorbent, and carbon molecular sieve are stacked and packed in an adsorption tower in a predetermined order. . X-type zeolite is preferred as the zeolite-based adsorbent. These adsorbents are preferably laminated in order from the helium gas introduction side, activated alumina, zeolite-based adsorbent, and carbon molecular sieve, or activated alumina, carbon molecular sieve, and zeolite-based adsorbent. When the nitrogen contained in the helium gas is large, it is preferable to use a large amount of zeolitic adsorbent, and when the amount of oxygen is large, it is preferable to use a large amount of carbon molecular sieve. Since the activated alumina mainly adsorbs carbon dioxide on the helium gas introduction side, it is possible to prevent the nitrogen adsorption effect from being lowered by the zeolite adsorbent thereafter. The volume ratio of the amounts of these adsorbents to be filled is, for example, activated alumina: X-type zeolite: carbon molecular sieve is set to 2-3: 7-4: 1-3. By causing most of the oxygen remaining in the helium gas to react with hydrogen in the second reaction step, the oxygen adsorption load by the PSA unit 10 can be reduced, and the adsorption tower 13 can be downsized.

The compressor 12 is connected to the inlet 13a of each adsorption tower 13 via the switching valve 13b.
Each of the inlets 13a of the adsorption tower 13 is connected to the atmosphere via a switching valve 13e and a silencer 13f.
Each of the outlets 13k of the adsorption tower 13 is connected to the outflow pipe 13m via the switching valve 13l, connected to the boosting pipe 13o via the switching valve 13n, and connected to the pressure equalization / washing outlet side pipe 13q via the switching valve 13p. Connected to the pressure equalization / cleaning inlet side pipe 13s through the switching valve 13r.
The outflow pipe 13m is connected to the TSA unit 20 via the pressure control valve 13t, and the pressure of the helium gas introduced into the TSA unit 20 is constant.
The booster pipe 13o is connected to the outflow pipe 13m via the flow rate control valve 13u and the flow rate indicating controller 13v, and the flow rate in the booster pipe 13o is adjusted to be constant, so that helium gas introduced into the TSA unit 20 is controlled. Flow rate fluctuation is prevented.
The pressure equalizing / cleaning outlet side pipe 13q and the pressure equalizing / cleaning inlet side pipe 13s are connected to each other via a pair of connecting pipes 13w, and a switching valve 13x is provided in each connecting pipe 13w.

In each of the first to fourth adsorption towers 13 of the PSA unit 10, an adsorption process, a reduced pressure I process (cleaning gas outflow process), a reduced pressure II process (equal pressure gas outflow process), a desorption process, a cleaning process (cleaning gas input process) The step-up I step (equal pressure gas entering step) and the step-up II step are sequentially performed. Each step will be described with reference to the first adsorption tower 13.
That is, only the switching valve 13b and the switching valve 13l are opened in the first adsorption tower 13, and the helium gas supplied from the dehydrator 5 is introduced from the compressor 12 into the first adsorption tower 13 through the switching valve 13b. As a result, at least carbon dioxide, nitrogen, and oxygen in the helium gas introduced in the first adsorption tower 13 are adsorbed by the adsorbent, so that the adsorption process is performed, and the helium gas with the reduced impurity content is the first. 1 is sent from the adsorption tower 13 to the TSA unit 20 through the outflow pipe 13m. At this time, a part of the helium gas sent to the outflow pipe 13m is sent to another adsorption tower (second adsorption tower 13 in the present embodiment) via the boosting pipe 13o and the flow rate control valve 13u, and the second adsorption. In the tower 13, a pressure increase II step is performed.
Next, the switching valves 13b and 13l of the first adsorption tower 13 are closed, the switching valve 13p is opened, the switching valve 13r of another adsorption tower (the fourth adsorption tower 13 in the present embodiment) is opened, and the switching valve 13x is opened. Open one of the. Thereby, the helium gas having a relatively small impurity content in the upper part of the first adsorption tower 13 is sent to the fourth adsorption tower 13 via the pressure equalization / washing inlet side pipe 13 s, and the reduced pressure I in the first adsorption tower 13. A process is performed. At this time, in the fourth adsorption tower 13, the switching valve 13e is opened, and a cleaning process is performed.
Next, the switching valve 13e of the fourth adsorption tower 13 is closed while the switching valve 13p of the first adsorption tower 13 and the switching valve 13r of the fourth adsorption tower 13 are open. As a result, the decompression II step is performed in which the fourth adsorption tower 13 recovers the gas until the internal pressures of the first adsorption tower 13 and the fourth adsorption tower 13 become uniform or substantially uniform. At this time, the two switching valves 13x may be opened depending on circumstances.
Next, a desorption process for desorbing impurities from the adsorbent is performed by opening the switching valve 13e of the first adsorption tower 13 and closing the switching valve 13p. The impurities are released into the atmosphere together with the gas through the silencer 13f. The
Next, the switching valve 13r of the first adsorption tower 13 is opened, the switching valves 13b and 13l of the second adsorption tower 13 in the state where the adsorption process is finished are closed, and the switching valve 13p is opened. As a result, helium gas having a relatively small impurity content in the upper part of the second adsorption tower 13 is sent to the first adsorption tower 13 via the pressure equalization / washing inlet side pipe 13s, and the first adsorption tower 13 performs the washing step. Is done. The gas used in the cleaning process in the first adsorption tower 13 is released into the atmosphere through the switching valve 13e and the silencer 13f. At this time, a reduced pressure I step is performed in the second adsorption tower 13.
Next, the step-up I process is performed by closing the switching valve 13e of the first adsorption tower 13 with the switching valve 13p of the second adsorption tower 13 and the switching valve 13r of the first adsorption tower 13 open. At this time, the two switching valves 13x may be opened depending on circumstances.
After that, the switching valve 13r of the first adsorption tower 13 is closed. Thereby, it will be in the standby state without a process once. This state continues until the step-up II process of the fourth adsorption tower 13 is completed. When the pressurization of the fourth adsorption tower 13 is completed and the adsorption process is switched from the third adsorption tower 13 to the fourth adsorption tower 13, the switching valve 13n of the first adsorption tower is opened. As a result, part of the helium gas sent to the outflow pipe 13m from another adsorption tower (the fourth adsorption tower 13 in the present embodiment) in the adsorption process is first passed through the booster pipe 13o and the flow rate control valve 13u. By being sent to the adsorption tower 13, the step-up II process is performed in the first adsorption tower 13.
The above steps are sequentially repeated in each of the first to fourth adsorption towers 13, so that helium gas with a reduced impurity content is continuously sent to the TSA unit 20.
The PSA unit 10 is not limited to the one shown in FIG. 2, and the number of towers may be other than 4, for example, 2 or 3, for example.

  A known TSA unit 20 can be used. For example, the TSA unit 20 shown in FIG. 3 is a two-column type, and a heat exchange type precooler 21 that precools the helium gas sent from the PSA unit 10 and heat that further cools the helium gas cooled by the precooler 21. The heat exchanger 24 that covers the exchange-type cooler 22, the first and second adsorption towers 23, and the respective adsorption towers 23 is provided. The heat exchanging unit 24 cools the adsorbent with a refrigerant during the adsorption process, and heats the adsorbent with a heat medium during the desorption process. Each adsorption tower 23 has a large number of inner tubes filled with an adsorbent. As the adsorbent, those suitable for adsorption of nitrogen and oxygen are used. As the adsorbent for nitrogen adsorption, for example, a zeolite adsorbent ion-exchanged with calcium (Ca) or lithium (Li) is preferably used, and an ion exchange rate of 70% or more is particularly preferable. A surface area of 600 m @ 2 or more is particularly preferable. As an adsorbent for oxygen adsorption, carbon molecular sieve is preferably used and is stacked with a zeolite adsorbent for nitrogen adsorption and packed into the adsorption tower 23.

The cooler 22 in the TSA unit 20 is connected to the inlet 23a of each adsorption tower 23 via a switching valve 23b.
Each of the inlets 23a of the adsorption tower 23 communicates with the atmosphere via the switching valve 23c.
Each of the outlets 23e of the adsorption tower 23 is connected to the outflow pipe 23g via the switching valve 23f, is connected to the cooling / pressure-increasing pipe 23i via the switching valve 23h, and is connected to the second cleaning pipe 23k via the switching valve 23j. Connected to.
The outflow pipe 23g constitutes a part of the precooler 21, and the helium gas sent from the PSA unit 10 is cooled by the purified helium gas flowing out from the outflow pipe 23g. The purified helium gas flows out from the outflow pipe 23g through the primary pressure control valve 23l.
The cooling / pressurizing piping 23i and the cleaning piping 23k are connected to the outflow piping 23g via a flow meter 23m, a flow control valve 23o, and a switching valve 23n.
The heat exchanging unit 24 is a multi-tube type, and includes an outer tube 24a surrounding a large number of inner tubes constituting the adsorption tower 23, a refrigerant supply source 24b, a refrigerant radiator 24c, a heat medium supply source 24d, and a heat medium radiator 24e. Is done. The refrigerant supply source 24b includes a refrigerator that cools the refrigerant to −10 ° C. to −50 ° C., the heat medium supply source 24d includes a heater that heats the heat medium to room temperature, and the refrigerator and heater use commercially available industrial products. It is preferable in terms of cost. In addition, the refrigerant supplied from the refrigerant supply source 24b is circulated through the outer pipe 24a and the refrigerant radiator 24c, and the heat medium supplied from the heat medium supply source 24d is supplied to the outer pipe 24a and the heat medium radiator 24e. A plurality of switching valves 24f are provided for switching to a state of circulation through the switching valves 24f. Further, a part of the cooler 22 is constituted by a pipe branched from the refrigerant radiator 24c, the helium gas is cooled in the cooler 22 by the refrigerant supplied from the refrigerant supply source 24b, and the refrigerant is returned to the tank 24g. .

In each of the first and second adsorption towers 23 of the TSA unit 20, an adsorption process, a desorption process, a cleaning process, a cooling process, and a pressure increasing process are sequentially performed.
That is, in the TSA unit 20, the helium gas supplied from the PSA unit 10 is cooled in the precooler 21 and the cooler 22, and then introduced into the first adsorption tower 23 via the switching valve 23b. At this time, the first adsorption tower 23 is cooled to −10 ° C. to −50 ° C. by circulating the refrigerant in the heat exchanging section 24, the switching valves 23c, 23h, and 23j are closed, and the switching valve 23f is Open and at least nitrogen and oxygen contained in the helium gas are adsorbed by the adsorbent. As a result, an adsorption step is performed in the first adsorption tower 23, and purified helium gas in which the impurity content is reduced flows out from the first adsorption tower 23 via the primary pressure control valve 23l, for example, a product tank (illustrated). (Omitted).
While the adsorption process is performed in the first adsorption tower 23, the desorption process, the cleaning process, the cooling process, and the pressure increasing process are performed in the second adsorption tower 23.
That is, in the second adsorption tower 23, the switching valves 23b and 23f are closed and the switching valve 23c is opened to perform the desorption process after the adsorption process is completed. Thereby, in the second adsorption tower 23, helium gas containing impurities is released into the atmosphere, and the pressure is reduced to almost atmospheric pressure. In this desorption process, the switching valve 24f of the heat exchanging section 24 that has circulated the refrigerant in the second adsorption tower 23 during the adsorption process is switched to the closed state to stop the circulation of the refrigerant, and the refrigerant is extracted from the heat exchanging section 24. The switching valve 24f that returns to the refrigerant supply source 24b is switched to the open state.
Next, in order to carry out the cleaning process in the second adsorption tower 23, the switching valves 23c, 23j of the second adsorption tower 23 and the switching valve 23n of the cleaning pipe 23k are opened, and the heat in the heat exchange type precooler 21 is heated. Part of the purified helium gas heated by the exchange is introduced into the second adsorption tower 23 via the cleaning pipe 23k. Thereby, in the second adsorption tower 23, desorption of impurities from the adsorbent and cleaning with purified helium gas are performed, and the helium gas used for the cleaning is released into the atmosphere together with the impurities from the switching valve 23c. In this cleaning step, the switching valve 24f of the heat exchange unit 24 for circulating the heat medium in the second adsorption tower 23 is switched to the open state.
Next, in order to perform the cooling process in the second adsorption tower 23, the switching valve 23j of the second adsorption tower 23 and the switching valve 23n of the cleaning pipe 23k are closed, and the switching valve 23h of the second adsorption tower 23 The switching valve 23n of the cooling / pressurizing pipe 23i is opened, and a part of the purified helium gas flowing out from the first adsorption tower 23 is introduced into the second adsorption tower 23 through the cooling / pressurizing pipe 23i. As a result, the purified helium gas that has cooled the inside of the second adsorption tower 23 is released into the atmosphere through the switching valve 23c. In this cooling process, the switching valve 24f for circulating the heat medium is switched to the closed state to stop the circulation of the heat medium, and the switching valve 24f that extracts the heat medium from the heat exchange unit 24 and returns it to the heat medium supply source 24d is provided. Switch to the open state. After completion of the extraction of the heat medium, the switching valve 24f of the heat exchanging unit 24 for circulating the refrigerant in the second adsorption tower 23 is switched to the open state to set the refrigerant circulation state. This refrigerant circulation state continues until the end of the next pressurization step and the subsequent adsorption step.
Next, in order to perform the pressure increasing process in the second adsorption tower 23, the switching valve 23c of the second adsorption tower 23 is closed, and a part of the purified helium gas flowing out from the first adsorption tower 23 is introduced. The inside of the two adsorption tower 23 is pressurized. This pressure increasing process is continued until the internal pressure of the second adsorption tower 23 becomes substantially equal to the internal pressure of the first adsorption tower 23. When the pressure increasing process is completed, the switching valve 23h of the second adsorption tower 23 and the switching valve 23n of the cooling / pressure increasing pipe 23i are closed, whereby all the switching valves 23b, 23c, 23f, 23h of the second adsorption tower 23 are closed. , 23j are closed, and the second adsorption tower 23 is in a standby state until the next adsorption step.
The adsorption process of the second adsorption tower 23 is performed in the same manner as the adsorption process of the first adsorption tower 23. While the adsorption process is performed in the second adsorption tower 23, the desorption process, the washing process, the cooling process, and the pressure increasing process are performed in the first adsorption tower 23 in the same manner as in the second adsorption tower 23.
The TSA unit 20 is not limited to the one shown in FIG. 3, and the number of towers may be 2 or more, for example, 3 or 4.

  In the helium gas to be purified by the purification apparatus α, the amount of oxygen initially contained is larger than the stoichiometric amount necessary to react with all of the initially contained hydrogen and carbon monoxide. Therefore, by introducing the helium gas to be purified heated by the heater 2 into the first reaction region 3A of the reaction device 3, hydrogen and carbon monoxide initially contained, and part of the oxygen initially contained Can be transformed into water and carbon dioxide by the first reaction step. The oxygen remaining in the helium gas by the execution of the first reaction step and the hydrogen added to the helium gas by the hydrogen addition device 4 can be converted to water by the second reaction step in the second reaction region 3B. Since the amount of hydrogen added by the hydrogen adding device 4 is less than the stoichiometric amount required to react with all of the oxygen remaining in the helium gas by the execution of the first reaction step, after the execution of the second reaction step Hydrogen can be prevented from remaining in the helium gas. Thus, the analysis of the impurity concentration of helium gas and the gas addition are performed only before the second reaction step without being performed before the first reaction step, and a large amount of carbon monoxide remains after the first reaction step. In addition, since a large amount of oxygen is prevented from remaining before the adsorption step, the purification operation can be simplified. In the above embodiment, the amount of hydrogen added by the hydrogenation device 4 is 95% or more and less than 100% of the stoichiometric amount necessary to react with all of the oxygen remaining in the helium gas. Most of this is reacted with hydrogen in the second reaction step, and in the adsorption step, it is sufficient to adsorb a little residual oxygen in the helium gas. Also, hydrogen, which is difficult to separate from helium gas depending on the adsorption method, can be removed from helium gas before the adsorption step. Further, the first reaction step and the second reaction step can be performed in a single reaction vessel 3a, and the equipment can be made compact and the cost can be reduced. The water produced by the second reaction step is removed from the helium gas by the dehydration operation by the dehydrator 5. As a result, the moisture content of the helium gas is reduced, so that the moisture adsorption load by the adsorption device 9 in the subsequent adsorption process can be reduced. Moreover, since the dehydration step is performed by cooling the helium gas after the second reaction step, it is not necessary to reheat the helium gas once cooled for the dehydration operation, and the energy consumption can be reduced. Further, the nitrogen and oxygen content in the helium gas can be further reduced by adsorbing the nitrogen and oxygen remaining in the helium gas to the adsorbent by the thermal swing adsorption method after the pressure swing adsorption process.

  FIG. 4 shows a modification of the reaction device 3. The difference from the above embodiment is that the reaction apparatus 3 has a first reaction vessel 3a ′, a second reaction vessel 3b ′, and a pipe 3c ′ for connecting the first reaction vessel 3a ′ and the second reaction vessel 3b ′. The inside of the first reaction vessel 3a ′ is a first reaction region 3A, the inside of the second reaction vessel 3b ′ is a second reaction region 3B, the inside of the pipe 3c ′ is a connection region 3C, and a catalyst is contained in the connection region 3C. Not filled. The hydrogen addition port 3e is disposed so as to communicate with the connection region 3C. The rest is the same as in the above embodiment.

Helium gas was purified using the purification apparatus α. In this embodiment, the TSA unit 20 was not used. The reactor 3 used was the one described in the modification.
The helium gas to be purified is recovered from what was released into the atmosphere after use in the optical fiber drawing process. As impurities, nitrogen was 23.43 mol%, oxygen was 6.28 mol%, and hydrogen was 50 mol. One containing 30 mol ppm of carbon, 30 mol ppm of carbon monoxide, 50 mol ppm of carbon dioxide, 2 mol ppm of methane, and 20 mol ppm of water was used. Note that the helium gas to be purified contains argon but is ignored.
The helium gas was heated by the heater 2 and then introduced into the reactor 3 at a flow rate of 3.31 L / min in a standard state. The first reaction vessel 3a ′ was filled with 45 mL of an alumina-supported ruthenium catalyst, and the reaction conditions in the first reaction vessel 3a ′ were a temperature of 190 ° C. and a space velocity of 5000 / h.
The oxygen concentration of the helium gas flowing out from the first reaction vessel 3a ′ is analyzed, and 98% of the stoichiometric amount of hydrogen required to generate water by reacting with all the oxygen is supplied from the hydrogenation device 4 to the helium gas. Added to. The second reaction vessel 3b ′ was filled with 150 mL of the same catalyst as the first reaction vessel 3a ′, and the reaction conditions in the second reaction vessel 3b ′ were the same as those in the first reaction vessel 3a ′.
The helium gas flowing out from the second reaction vessel 3b ′ was cooled to 25 ° C. by the first dehydrator 5a, and the liquefied water was removed from the helium gas. As a result, the water content of the helium gas was reduced to 25 ° C. saturation (about 3% when the total pressure was atmospheric pressure). Next, helium gas was introduced into the packed column of dehydrated activated alumina used as the second dehydrator 5b, and the water content was reduced to 95 ppm. The packed column of the second dehydrator 5b was packed with 250 mL of activated alumina (KHD-24 manufactured by Sumitomo Chemical).
The content of helium gas impurities flowing out from the second dehydrator 5b was reduced by the adsorption device 9. The PSA unit 10 is a four-column type, and activated alumina (KHD-24 manufactured by Sumitomo Chemical), LiX-type zeolite molecular sieve (NSA-700 manufactured by Tosoh Corporation), and carbon molecular sieve (GN manufactured by Kuraray Chemical) are used as adsorbents in the respective columns. -UC-H) was stacked and filled with a total of 1.25 L. The volume ratio of these adsorbents was activated alumina: zeolite molecular sieve: carbon molecular sieve = 25: 65: 10. The adsorption pressure in the PSA unit 10 was set to 0.9 MPa, the desorption pressure was set to 0.03 MPa, and the cycle time was set to 250 seconds.
The composition of impurities in the purified helium gas flowing out from the PSA unit 10 was as follows.
It was oxygen 1.0 mol ppm, nitrogen 1.2 mol ppm, hydrogen less than 1 mol ppm, carbon monoxide less than 1 mol ppm, carbon dioxide less than 1 mol ppm, methane less than 1 mol ppm, and moisture less than 1 mol ppm. Argon contained in the helium gas to be purified was ignored.
Here, the oxygen concentration of the helium gas is a Teledyne micro oxygen concentration meter model 311, the methane concentration is GC-FID manufactured by Shimadzu Corporation, and the concentrations of carbon monoxide and carbon dioxide are GC-FID manufactured by Shimadzu Corporation. And measured through a methanizer. The hydrogen concentration was measured using GC-PID manufactured by GL Science. The nitrogen concentration was measured using GC-PDD manufactured by Shimadzu Corporation. The moisture was measured using a dew point meter DEWMET-2 manufactured by GE Sensing Japan.

The volume ratio of the adsorbent packed in each column of the PSA unit 10 was activated alumina: zeolite molecular sieve: carbon molecular sieve = 25: 60: 15. Otherwise, helium gas was purified in the same manner as in Example 1.
The composition of impurities in the purified helium gas flowing out from the PSA unit 10 was as follows.
Less than 1 mol ppm of oxygen, 1.3 mol ppm of nitrogen, less than 1 mol ppm of hydrogen, less than 1 mol ppm of carbon monoxide, less than 1 mol ppm of carbon dioxide, less than 1 mol ppm of water.

The purified helium gas flowing out from the PSA unit 10 was further purified using the TSA unit 20. The TSA unit 20 is a two-column type, and each adsorption tower is filled with 1.2 L of CaX type zeolite molecular sieve (SA-600A manufactured by Tosoh Corporation) and 0.3 L of carbon molecular sieve as an adsorbent. The adsorption pressure in the TSA unit 20 was 0.8 MPaG, the desorption pressure was 0.03 MPaG, the adsorption temperature was −35 ° C., and the desorption temperature was 40 ° C.
The composition of impurities in the purified helium gas flowing out of the TSA unit 20 was as follows.
Less than 1 mol ppm of oxygen, less than 1 mol ppm of nitrogen, less than 1 mol ppm of hydrogen, less than 1 mol ppm of carbon monoxide, less than 1 mol ppm of carbon dioxide, less than 1 mol ppm of methane, and less than 1 mol ppm of water.

The amount of activated alumina packed in the packed column of activated alumina for dehydration used as the second dehydrator 5b is double that in Example 1, and activated alumina is not used as the adsorbent to be packed in each column of the PSA unit 10, and zeolite 1.0 L of molecular sieve and 0.25 L of carbon molecular sieve were filled. Otherwise, helium gas was purified in the same manner as in Example 1.
The composition of impurities in the purified helium gas flowing out from the PSA unit 10 was as follows.
Oxygen 1.2 mol ppm, nitrogen 1.4 mol ppm, hydrogen less than 1 mol ppm, carbon monoxide less than 1 mol ppm, carbon dioxide less than 1 mol ppm, moisture less than 1 mol ppm.

Comparative Example 1

The helium gas was purified without reducing the water content of the helium gas by the dehydrator 5. Others were the same as in Example 1.
The composition of impurities in the purified helium gas flowing out from the PSA unit 10 was as follows.
Oxygen 1.9 mol ppm, nitrogen 200 ppm, hydrogen less than 1 ppm, carbon monoxide less than 1 ppm, carbon dioxide less than 1 ppm, moisture less than 1 ppm.

  The present invention is not limited to the above-described embodiments, modifications, and examples. For example, the helium gas purified according to the present invention is not limited to the recovered helium gas released into the atmosphere after use in the optical fiber drawing process, and at least hydrogen, carbon monoxide, nitrogen, and oxygen as impurities In which the amount of oxygen initially contained is greater than the stoichiometric amount required to react with all of the initially contained hydrogen and carbon monoxide. Further, the adsorption by the thermal swing adsorption method is not essential, and the purification apparatus may not include the TSA unit.

  α ... purification device, 2 ... heater, 3 ... reaction device, 3A ... first reaction zone, 3B ... second reaction zone, 3C ... connection zone, 3a ... reaction vessel, 3b ... gas inlet, 3c ... gas outlet 3d ... Gas extraction port, 3e ... Hydrogen addition port, 4 ... Hydrogen addition device, 4a ... Hydrogen supply source, 4b ... Analyzer, 4c ... Hydrogen amount regulator, 5 ... Dehydration device, 9 ... Adsorption device, 10 ... Pressure Swing adsorption unit

Claims (7)

Contains at least hydrogen, carbon monoxide, nitrogen, and oxygen as impurities, and the amount of oxygen initially contained is greater than the stoichiometric amount required to react with all of the initially contained hydrogen and carbon monoxide. When purifying a lot of helium gas,
A first reaction step of reacting hydrogen and carbon monoxide originally contained in the helium gas with oxygen contained from the beginning using a catalyst;
A hydrogenation step of adding less than the stoichiometric amount of hydrogen required to react with all of the oxygen remaining in the helium gas by performing the first reaction step;
A second reaction step in which oxygen remaining in the helium gas by the execution of the first reaction step is reacted with hydrogen added in the hydrogen addition step using a catalyst;
A dehydration step of reducing the water content of the helium gas after the execution of the second reaction step by a dehydration operation;
A method of purifying helium gas, comprising: a pressure swing adsorption step of adsorbing at least carbon dioxide, nitrogen and oxygen remaining in the helium gas after the dehydration operation to an adsorbent by a pressure swing adsorption method.   The amount of hydrogen added in the hydrogen addition step is 95% or more and less than 100% of a stoichiometric amount necessary for reacting with all of the oxygen remaining in the helium gas by the execution of the first reaction step. 2. The method for purifying helium gas according to 1.   The method for purifying helium gas according to claim 1, wherein the dehydration step is performed by cooling the helium gas after the second reaction step.   The activated alumina, the zeolitic adsorbent, and the carbon molecular sieve are used as the adsorbent, and after adsorbing carbon dioxide on the activated alumina, nitrogen is adsorbed on the zeolitic adsorbent. The purification method of helium gas as described.   5. The thermal swing adsorption step of adsorbing nitrogen and oxygen remaining in the helium gas to an adsorbent by a thermal swing adsorption method at −10 ° C. to −50 ° C. after the pressure swing adsorption step. The method for purifying helium gas according to any one of the above. Contains at least hydrogen, carbon monoxide, nitrogen, and oxygen as impurities, and the amount of oxygen initially contained is greater than the stoichiometric amount required to react with all of the initially contained hydrogen and carbon monoxide. An apparatus for purifying a large amount of helium gas,
A heater for heating the helium gas;
A first reaction region filled with a catalyst for reacting hydrogen and carbon monoxide with oxygen; a second reaction region filled with a catalyst for reacting hydrogen with oxygen; the first reaction region; A reaction device having a connection region with two reaction regions;
A hydrogen supply device having a hydrogen supply source, an analyzer for determining an oxygen concentration of helium gas, and a hydrogen amount adjuster for adjusting an amount of hydrogen supplied from the hydrogen supply source according to the determined oxygen concentration;
A dehydrator,
An adsorption device connected to the dehydration device,
The reaction apparatus has a gas inlet connected to the heater, a gas outlet connected to the dehydrator, a gas extraction port connected to the analyzer, and the amount of hydrogen adjusted to the hydrogen supply source And a hydrogen addition port connected through a vessel,
The gas introduction so that the helium gas introduced from the gas introduction port into the reaction apparatus flows out from the gas outlet after sequentially passing through the first reaction region, the connection region, and the second reaction region. A mouth, the first reaction region, the connection region, the second reaction region, and the gas outlet are disposed;
The gas extraction port is disposed at a position where helium gas can be extracted in the connection region, and the hydrogen addition port can add hydrogen to the helium gas introduced into the second reaction region after passing through the first reaction region. Placed in position,
The amount of hydrogen added to the helium gas from the hydrogen addition port is less than the stoichiometric amount necessary to react with all of the oxygen remaining in the helium gas by the reaction in the first reaction region. The amount of hydrogen supplied from the hydrogen supply source is adjusted by the hydrogen amount adjuster according to the oxygen concentration of the helium gas in the connection region determined by the analyzer,
The dehydrator is connected to the gas outlet so that the moisture content of the helium gas flowing out of the gas outlet is reduced by a dehydration operation;
The said adsorption | suction apparatus has a pressure swing adsorption | suction unit which adsorb | sucks at least carbon dioxide, nitrogen, and oxygen in the said helium gas to an adsorbent by a pressure swing adsorption method, The refinement | purification apparatus of helium gas characterized by the above-mentioned.   The helium gas purification apparatus according to claim 6, wherein the reaction apparatus has a single reaction vessel, and the first reaction region, the connection region, and the second reaction region are provided in the reaction vessel.

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