Method and apparatus for producing high-purity hydrogen and high-purity oxygen

Abstract

A method and apparatus for producing high-purity hydrogen and high-purity oxygen are provided, which are capable of efficiently producing high-purity hydrogen and high-purity oxygen from oxygen and hydrogen generated by water electrolysis. [Solution] The system comprises a degassing means 32 for raw pure water 3, an electrolysis means 33 for generating oxygen and hydrogen by water electrolysis using a polymer electrolyte membrane, an oxygen purification means 35, a hydrogen purification means 37, and a means for supplying the purge gas circulated during regeneration of the adsorbent used in the oxygen purification means 35 to the degassing means 32 for the raw pure water 3.

Description

[Technical Field]

[0001] The present invention relates to a method and an apparatus for producing high-purity hydrogen and high-purity oxygen. [Background technology]

[0002] Water electrolysis is a known method for producing hydrogen, and the oxygen generated during this process may also be used.

[0003] Patent Document 1 proposes a method for producing high-purity hydrogen by previously degassing water to be supplied to the electrolysis of alkali metal chlorides. Components dissolved in water are released into the gas phase during electrolysis, reducing the purity of the product hydrogen gas. Therefore, by previously degassing the water, it is possible to extract a high-purity product gas with fewer impurities. Here, according to Henry's law, the amount of components dissolved in water increases the higher the partial pressure or the lower the temperature. In water that is in a state of dissolution equilibrium with the atmosphere, which is commonly used in water electrolysis, nitrogen is the most dominant impurity. Patent Document 1 proposes a method for degassing this nitrogen by degassing under reduced pressure. However, degassing under reduced pressure requires additional power and is inefficient.

[0004] Patent Document 2 proposes a high-purity oxygen and hydrogen production device that includes a solid polymer electrolyte water electrolysis cell, a degassing means, and a dehumidifying means that separately dehumidifies the hydrogen and oxygen generated. Patent Document 2 uses a membrane degassing module as the degassing means, and claims that the purity of the generated oxygen and hydrogen can be increased to 99.999%. However, a vacuum pump is required when using a membrane as the degassing means, which is inefficient in terms of power and cost.

[0005] Patent Document 3 proposes a method for removing impurities from hydrogen gas, which is characterized by blowing oxygen into a pure water storage tank to remove dissolved gases in the pure water, and then dehumidifying and deoxidizing the hydrogen generated from the anode in a method for generating hydrogen and oxygen by electrolysis. However, there is no mention of efficiently utilizing the oxygen generated.

[0006] Patent Document 4 proposes a method for generating hydrogen and oxygen by electrolysis, in which the generated hydrogen and oxygen are introduced into a purifier comprising an oxidation catalyst and a moisture adsorbent, respectively, to convert the oxygen contained in the hydrogen and the hydrogen contained in the oxygen into moisture, which is then adsorbed and removed, thereby obtaining high-purity oxygen and hydrogen. However, no mention is made of degassing the raw pure water, and impurities derived from dissolved gases are contained in the produced oxygen and hydrogen, requiring additional purification.

[0007] Patent Document 5 proposes a method for generating high-purity hydrogen by electrolysis in which regeneration gas that has passed through a dehumidifying and purifying section provided downstream of an electrolytic cell, or regeneration gas before passing through the section, is introduced into a water storage tank to efficiently degas raw pure water. However, there is no mention of using the oxygen that is co-produced. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Japanese Patent Application Publication No. 59-208085 [Patent Document 2] Patent No. 3132594 [Patent Document 3] Japanese Patent Publication No. 58-189383 [Patent Document 4] Patent No. 2735723 [Patent Document 5] Patent No. 4223010 Summary of the Invention [Problem to be solved by the invention]

[0009] An object of the present invention is to provide a method and apparatus for producing high-purity hydrogen and high-purity oxygen that can efficiently produce high-purity hydrogen and high-purity oxygen from oxygen and hydrogen generated by water electrolysis. [Means for solving the problem]

[0010] In order to solve the above problems, the present invention provides the following means. [1] A method for producing high-purity hydrogen and high-purity oxygen, comprising: a degassing step for raw pure water; an electrolysis step for generating oxygen and hydrogen by water electrolysis using a polymer electrolyte membrane; a purification step for the oxygen generated by the electrolysis step; a purification step for the hydrogen generated by the electrolysis step; and a step for supplying a purge gas circulated during regeneration of an adsorbent used in the oxygen purification step to the degassing step for raw pure water. [2] The method for producing high-purity hydrogen and high-purity oxygen according to [1], characterized in that the flow rate of the purge gas supplied to the degassing step is adjusted according to the flow rate of oxygen generated by the electrolysis step and / or the flow rate of hydrogen generated by the electrolysis step. [3] An apparatus for producing high-purity hydrogen and high-purity oxygen, comprising: a means for degassing raw pure water; an electrolysis means for generating oxygen and hydrogen by water electrolysis using a polymer electrolyte membrane; a means for purifying the oxygen generated by the electrolysis means; a means for purifying the hydrogen generated by the electrolysis means; and a means for supplying the purge gas circulated during regeneration of the adsorbent used in the oxygen purification means to the means for degassing raw pure water. [4] The apparatus for producing high-purity hydrogen and high-purity oxygen according to [3], characterized in that the flow rate of the purge gas supplied to the degassing means is adjusted according to the flow rate of oxygen generated by the electrolysis means and / or the flow rate of hydrogen generated by the electrolysis means. [Effects of the Invention]

[0011] According to the present invention, high-purity hydrogen and high-purity oxygen can be efficiently produced from oxygen and hydrogen generated by water electrolysis. [Brief explanation of the drawings]

[0012] [Figure 1] 1 is a schematic diagram showing an example of a production apparatus for high-purity hydrogen and high-purity oxygen. [Figure 2] FIG. 2 is a schematic diagram showing the configuration of a gas purification means of the first embodiment. [Figure 3] 1 is a schematic diagram illustrating an example of an adsorption-type dehumidification device and an adsorption-type purification device. [Figure 4] FIG. 4 is a schematic diagram showing the configuration of a gas purification means of a second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0013] The present invention will be described below based on preferred embodiments.

[0014] The method for producing high-purity hydrogen and high-purity oxygen of this embodiment includes a degassing step of raw pure water, an electrolysis step of generating oxygen and hydrogen by water electrolysis, a purification step of the oxygen generated by the electrolysis step, a purification step of the hydrogen generated by the electrolysis step, and a step of supplying the purge gas that has circulated during the regeneration of the adsorbent used in the oxygen purification step to the degassing step of raw pure water.

[0015] The apparatus for producing high-purity hydrogen and high-purity oxygen of this embodiment includes a means for degassing raw pure water, an electrolysis means for generating oxygen and hydrogen by water electrolysis, a means for purifying the oxygen generated by the electrolysis means, a means for purifying the hydrogen generated by the electrolysis means, and a means for supplying the purge gas circulated during regeneration of the adsorbent used in the oxygen purification means to the means for degassing raw pure water.

[0016] 1 is a schematic diagram showing an example of an apparatus for producing high-purity hydrogen and high-purity oxygen. The production apparatus 50 of this embodiment includes at least a degassing means 32, an electrolysis means 33, an oxygen purification means 35, and a hydrogen purification means 37. The production apparatus 50 in the illustrated example further includes a pure water production means 30, a pure water storage tank 31, an oxygen gas-liquid separation tank 34, and a hydrogen gas-liquid separation tank 36.

[0017] Tap water such as municipal water or industrial water is generally used as raw water 1. Raw water 1 is supplied to pure water production means 30, where ions and the like are removed, to produce raw pure water 2. The pure water production means 30 is not particularly limited, but examples include ion exchange, distillation, and membrane separation. Raw pure water 2 is stored in a pure water storage tank 31 and supplied to degassing means 32 using a pump (not shown) as raw pure water 3. According to Henry's law, raw pure water 3, which is in equilibrium with the atmosphere in terms of gas dissolution, contains dissolved nitrogen at approximately 10 ppm, oxygen at approximately 3 ppm, and carbon dioxide at approximately 0.3 ppm.

[0018] The degassing means 32 is a method for removing dissolved gases other than oxygen. Suitable methods include a gas-liquid mixing stripping operation as described in Japanese Patent No. 4323631 and a bubbling operation, but are not limited to these. This degassing operation may be repeated multiple times. This produces raw pure water 4 with dissolved nitrogen and carbon dioxide levels of 10 ppb or less.

[0019] The raw pure water 4, with a reduced amount of dissolved gases, is supplied to the electrolysis means 33 using a pump (not shown). An electrolytic cell using a polymer electrolyte membrane can be used as the electrolysis means 33, and a proton exchange membrane (PEM) type electrolytic cell is preferred. In a PEM type electrolytic cell, the raw pure water 4 is supplied to the anode side. The water is electrolyzed into protons and oxygen. The generated protons pass through the proton exchange membrane, move to the cathode side, and become hydrogen on the cathode.

[0020] The oxygen 5 generated in the electrolysis means 33 is introduced into a gas-liquid separation tank 34. In the gas-liquid separation tank 34, liquid water is removed and oxygen gas 6 is extracted. The liquid phase side of the gas-liquid separation tank 34 may be rejoined with the pure water storage tank 31 or the degassing means 32 via a pump (not shown) and used as the raw pure water 2, 3, 4 for electrolysis.

[0021] The oxygen gas 6 extracted from the gas-liquid separation tank 34 is purified by oxygen purification means 35 to remove impurities. The oxygen gas 6 contains saturated moisture and a trace amount of hydrogen. The trace amount of hydrogen comes from hydrogen 9 mixed into the oxygen 5 by passing through the polymer electrolyte membrane from the cathode side to the anode side in the electrolysis means 33, for example.

[0022] The oxygen purification means 35 is not particularly limited, but may be at least one selected from a gas-liquid separation type, a cooling type, an adsorption type, a catalytic type, etc. Furthermore, oxygen purification means 35 including at least an adsorption type using an adsorbent is employed. These purification means may be any means capable of converting the oxygen gas 6 obtained by the electrolysis means 33 into high-purity oxygen gas 8, and multiple types may be combined depending on the purpose of purification.

[0023] An example of a gas-liquid separation type oxygen purification means 35 is removal of condensed water using a drain separator. An example of a cooling type oxygen purification means 35 is dehumidification using a refrigeration dryer. An example of an adsorption type oxygen purification means 35 is dehumidification using an adsorbent or removal of impurity gas components. An example of a catalytic type oxygen purification means 35 is removal of impurity gas components using a catalyst. Two or more types of oxygen purification means 35 may be combined.

[0024] In adsorption purification, multiple adsorption towers are provided and the adsorption and regeneration steps are repeatedly performed to continuously produce purified gas. A suitable method for regenerating the adsorbent in adsorption-type purification means is to use a temperature swing.

[0025] The exhaust gas 7 used to regenerate the adsorbent in the oxygen purification means 35 is supplied to the degassing means 32 and used to remove impurities from the raw pure water 3. The flow rate of the exhaust gas 7 and the adsorption tower switching time of the adsorption purification section in the oxygen purification means 35 are preferably adjusted depending on the flow rate of oxygen 5 generated in the electrolysis step, the flow rate of hydrogen 9 generated in the electrolysis step, the flow rate of oxygen gas 6 purified in the oxygen purification means 35, the amount of electric power input to the electrolysis means 33, etc.

[0026] The high-purity oxygen gas 8 purified by the oxygen purification means 35 has reduced contents of other impurity gas components, such as moisture and hydrogen, that were contained in the unpurified oxygen gas 6. For use in technical fields that require the use of highly purified oxygen and hydrogen, such as the semiconductor industry, it is preferable that the contents of each impurity component in the high-purity oxygen gas 8 are 10 ppb or less.

[0027] The oxygen concentration in the high-purity oxygen gas 8 is preferably 99.999% or more (total impurities of 10 ppm or less), but can also be 99.9999% or more (total impurities of 1 ppm or less), 99.99999% or more (total impurities of 0.1 ppm or less), etc. These concentrations are based on volume.

[0028] The hydrogen 9 generated in the electrolysis means 33 is introduced into a gas-liquid separation tank 36. In the gas-liquid separation tank 36, liquid water is removed and hydrogen gas 10 is extracted. The liquid phase side of the gas-liquid separation tank 36 may be rejoined with the pure water storage tank 31 or the degassing means 32 via a pump (not shown) and used as the raw pure water 2, 3, 4 for electrolysis.

[0029] The hydrogen gas 10 extracted from the gas-liquid separation tank 36 is purified by hydrogen purification means 37 to remove impurities. The hydrogen gas 10 contains saturated moisture and other impurity gas components. The configuration of the hydrogen purification means 37 may be similar to that of the oxygen purification means 35. The hydrogen purification means 37 may be any purification means that converts the hydrogen gas 10 obtained by the electrolysis means 33 into high-purity hydrogen gas 12, and multiple types of hydrogen purification means 37 may be combined depending on the purpose of purification.

[0030] The hydrogen purification means 37 is not particularly limited, but may be at least one selected from a gas-liquid separation type, a cooling type, an adsorption type, a catalytic type, etc. The hydrogen purification means 37 may include an adsorption type hydrogen purification means 37 that uses an adsorbent. The exhaust gas 11 used to regenerate the adsorbent in this hydrogen purification means 37 is discharged into the atmosphere.

[0031] The high-purity hydrogen gas 12 purified by the hydrogen purification means 37 has reduced content of moisture and other impurity gas components that were contained in the unpurified hydrogen gas 10. The content of each impurity component in the high-purity hydrogen gas 12 is preferably 10 ppb or less.

[0032] The hydrogen concentration in the high-purity hydrogen gas 12 is preferably 99.999% or more (total impurities of 10 ppm or less), but can also be 99.9999% or more (total impurities of 1 ppm or less), 99.99999% or more (total impurities of 0.1 ppm or less), etc. These concentrations are based on volume.

[0033] 2 is a schematic diagram showing a first embodiment of the oxygen purification means 35. The gas purification means 100 of the first embodiment includes a drain removal device 130, an adsorption-type dehumidification device 131, a heat exchanger 132, a heating means 133, a catalyst tower 134, and an adsorption-type purification device 135.

[0034] Oxygen gas 101 containing impurity components such as moisture and hydrogen is passed through a drain removal device 130 to remove condensed water. Oxygen gas 102 from which the condensed water has been removed is introduced into an adsorption-type dehumidification device 131.

[0035] The adsorption-type dehumidifier 131 is provided with two adsorption towers. Each adsorption tower is filled with one or more types of adsorbent selected from among general-purpose adsorbents such as activated alumina, zeolite, activated carbon, and silica gel. The two adsorption towers alternate between an adsorption process and a regeneration process. Moisture is removed from the oxygen gas 102 using the adsorption tower in the adsorption process. Regeneration exhaust gas is released from the adsorption tower in the regeneration process. Details of the adsorption-type dehumidifier 131 will be described later.

[0036] The moisture concentration in the oxygen gas 103 leaving the adsorption-type dehumidifier 131 is preferably 10 volppm or less, and particularly preferably 5 volppm or less. If the oxygen gas 103 contains more moisture than the upper limit, it is difficult to fully demonstrate the performance of the subsequent purification stage.

[0037] Oxygen gas 103 treated by adsorption dehumidifier 131 passes through heat exchanger 132 and is heated. Oxygen gas 104 leaving heat exchanger 132 is heated by heating means 133. Oxygen gas 105 leaving heating means 133 is introduced into catalytic tower 134. In catalytic tower 134, hydrogen contained in oxygen gas 105 reacts to produce water.

[0038] The temperature of oxygen gas 105 heated by heating means 133 and introduced into the inlet of catalyst tower 134 is preferably 100° C. or higher, particularly preferably 150° C. or higher. If the temperature of oxygen gas 105 is lower than the lower limit, the catalyst may not exhibit sufficient performance, and hydrogen removal may be insufficient.

[0039] The catalyst used in the catalyst tower 134 is preferably a catalyst in which a noble metal element is supported on a carrier. The noble metal is preferably one or more noble metal elements selected from palladium, platinum, rhodium, ruthenium, and silver. The carrier is preferably selected from alumina, ceria, silica, and titania.

[0040] The oxygen gas 106 with a reduced hydrogen concentration is heat exchanged with oxygen gas 103 in heat exchanger 132 and cooled to below 40°C. The oxygen gas 107 is then introduced into adsorption-type purification device 135. The adsorption-type purification device 135 can remove trace amounts of moisture not removed in adsorption-type dehumidification device 131, moisture produced by the reaction of hydrogen in catalyst tower 134, and other arbitrary impurity components. The high-purity oxygen gas 108 obtained at the outlet of adsorption-type purification device 135 has the concentrations of various impurities reduced to 10 vol ppb or less.

[0041] The adsorption-type purification apparatus 135 has a similar configuration to the adsorption-type dehumidification apparatus 131 and is provided with two adsorption towers. Each adsorption tower is filled with an adsorbent made of one or more of activated alumina, zeolite, and silica gel. The two adsorption towers alternate between an adsorption process and a regeneration process. Impurities are removed from oxygen gas 107 using the adsorption tower in the adsorption process. Regeneration exhaust gas 109 is released from the adsorption tower in the regeneration process. This regeneration exhaust gas 109 is supplied as exhaust gas 7 to the degassing means 32 for raw pure water 3. Details of the adsorption-type purification apparatus 135 will be described later.

[0042] The flow rate of the regeneration exhaust gas 109 is preferably 10% or less, and particularly preferably 5% or less, of the flow rate of the oxygen gas 107 to be purified. The regeneration exhaust gas 109 cannot be used as purified high-purity oxygen gas 108. Therefore, if the flow rate of the regeneration exhaust gas 109 exceeds the upper limit, the production efficiency of the high-purity oxygen gas 108 will deteriorate, which will be uneconomical.

[0043] Next, the adsorption dehumidifier 131 and the adsorption purification device 135 will be described in detail. The adsorption devices used in the adsorption dehumidifier 131 and the adsorption purification device 135 include two adsorption towers. The two adsorption towers repeat an adsorption process and a regeneration process at equal intervals. The regeneration process is composed of a depressurization process, a heating process, a cooling process, and a pressurization process.

[0044] In the depressurization process, the pressure inside the adsorption tower is released through the exhaust gas discharge pipe. In the heating process, regeneration heating gas heated by the regeneration gas heater is introduced into the adsorption tower. In the cooling process, regeneration cooling gas is introduced into the adsorption tower through the regeneration cooling gas introduction pipe to lower the temperature of the adsorbent to the temperature of the adsorption process. In the charging process, the pressure inside the adsorption tower is increased to the pressure of the adsorption process using gas purified in the other adsorption tower through the charging gas pipe.

[0045] 3 is a schematic diagram showing an example of the adsorption dehumidification device 131 and the adsorption purification device 135. This adsorption device 200 includes two adsorption towers 230a, 230b, purified raw material gas inlet valves 231a, 231b, exhaust gas discharge valves 232a, 232b, regeneration gas inlet valves 233a, 233b, pressurized gas inlet pipe valves 234a, 234b, purified gas outlet valves 235a, 235b, regeneration cooling gas inlet valve 236, regeneration heating gas inlet valve 237, and regeneration gas heater 238.

[0046] The purified raw gas 201 is introduced into the adsorption towers 230a and 230b through purified raw gas inlet pipes 211 and 241. The purified gas 202 is discharged through purified gas outlet pipes 245, 251, and 212. The regeneration gas 203 is introduced into the adsorption towers 230a and 230b through regeneration gas inlet pipes 213 and 243. The exhaust gas 204 is discharged from the adsorption tower inlet sides 240a and 240b through exhaust gas discharge pipes 214 and 242. A portion of the purified gas 202 can be introduced into the adsorption tower outlet sides 250a and 250b through pressurized gas pipes 244 and 252. The regeneration gas inlet pipe 213 includes a regeneration cooling gas inlet pipe 246 and a regeneration heating gas inlet pipe 247.

[0047] The regeneration gas 203 is generally a portion of the purified gas 202 from which moisture has been removed, which is then diverted for use. The flow rate of the regeneration gas 203 is preferably 10% or less of the flow rate of the purified gas 202, and particularly preferably 5% or less. Since the regeneration gas 203 cannot be used as the purified gas 202 for subsequent processing, if the flow rate of the regeneration gas 203 exceeds the upper limit, this leads to a deterioration in purification efficiency and is uneconomical. The regeneration gas that has passed through the adsorption tower in the regeneration step is released into the atmosphere as exhaust gas 204. In this case, a closed TSA method, as disclosed in Japanese Patent No. 4313882, etc., in which the regeneration exhaust gas is recirculated into the feed gas side, may be used.

[0048] The inlet temperature of the purified raw material gas 201 in the adsorption dehumidifier 131 is preferably 5 to 60°C, and particularly preferably 5 to 40°C. If the inlet temperature is higher than the upper limit of the above range, the amount of moisture introduced into the adsorption tower increases, making the adsorption tower larger and uneconomical. The purified gas 202 from which moisture has been removed in the adsorption tower is used for the next process.

[0049] The temperature in the adsorption step in the adsorption-type purification apparatus 135 is preferably 5 to 60° C., particularly preferably 5 to 40° C. If the temperature in the adsorption step is higher than the upper limit of the above range, the removal performance of the adsorbent will decrease, and the adsorption tower will become larger, which is uneconomical.

[0050] The temperature of the regeneration heating gas obtained by heating with the regeneration gas heater 238 in the adsorption dehumidifier 131 is preferably 150 to 250°C, and particularly preferably 200 to 250°C. If the temperature of the regeneration heating gas is lower than the lower limit of the above range, moisture is not sufficiently desorbed from the adsorbent, and the performance of the adsorbent deteriorates. If the temperature of the regeneration heating gas is higher than the upper limit of the above range, the cost of increasing the heat resistance temperature of the valve provided in the dehumidification means increases, which is uneconomical.

[0051] The temperature of the regeneration heating gas obtained by heating with the regeneration gas heater 238 in the adsorption-type purification device 135 is preferably 200 to 350°C, in order to perform a more advanced dehumidification purification process than in the adsorption-type dehumidification device 131. If the temperature of the regeneration heating gas is lower than the lower limit of the above range, moisture will not be sufficiently desorbed from the adsorbent, and the performance of the adsorbent will deteriorate. If the temperature of the regeneration heating gas is higher than the upper limit of the above range, the cost of increasing the heat resistance temperature of the valve provided in the dehumidification means will increase.

[0052] 4 is a schematic diagram showing a second embodiment of the oxygen purification means 35. As in the first embodiment, the gas purification means 300 of the second embodiment includes a drain removal device 330, an adsorption-type dehumidification device 331, a heat exchanger 332, a heating means 333, a catalyst tower 334, and an adsorption-type purification device 335. As in the first embodiment, oxygen gases 301, 302, 303, 304, 305, 306, and 307 are sequentially processed to obtain high-purity oxygen gas 308.

[0053] In the second embodiment, part or all of the regeneration exhaust gas 309 from the adsorption-type purification device 335 is supplied as the feed gas 310 to the degassing means for raw pure water, or all of the regeneration exhaust gas 309 plus part of the oxygen gas 303 dehumidified by the adsorption-type dehumidification device 331 is supplied. This suppresses the loss of oxygen gas and enables more efficient oxygen generation. [Example]

[0054] The present invention will be specifically described below with reference to examples.

[0055] Example 1 High-purity hydrogen and high-purity oxygen were continuously produced using the gas purification means 100 of Figure 2 as the oxygen purification means 35 of Figure 1. The hydrogen purification means 37 of Figure 1 is similar to the gas purification means 100 of Figure 2, but is configured such that the regeneration exhaust gas 109 is not supplied to the degassing means 32.

[0056] In both the oxygen purification means 35 and the hydrogen purification means 37, the amount of gas used as regeneration gas in the adsorption-type purification device 135 was 3% of the amount of gas generated in the electrolysis means 33. In addition, in both the oxygen purification means 35 and the hydrogen purification means 37, the amount of exhaust gas used as regeneration gas in the adsorption-type dehumidification device 131 and released into the atmosphere was 10% of the amount of gas generated in the electrolysis means 33. The degassing means 32 was supplied with gas that had passed through the adsorption tower as regeneration gas in the oxygen gas adsorption-type purification device 135.

[0057] The inlet pressure of the oxygen purification means 35 was 0.8 MPa and 25°C, and the impurity components contained in the oxygen gas 6 at the inlet were saturated moisture and 3 ppm hydrogen, and the nitrogen and carbon dioxide contents were 0.1 ppm or less. The inlet pressure of the hydrogen purification means 37 was 0.8 MPa and 25°C, and the impurity components contained in the hydrogen gas 10 at the inlet were saturated moisture and 1 ppm or less oxygen, and the nitrogen and carbon dioxide contents were 0.1 ppm or less.

[0058] The oxygen gas obtained at the outlet of the oxygen purification means 35 contained 0.1 ppm or less of hydrogen, nitrogen, moisture, and carbon dioxide. The hydrogen gas obtained at the outlet of the hydrogen purification means 37 contained 0.1 ppm or less of oxygen, nitrogen, moisture, and carbon dioxide.

[0059] Example 2 High-purity hydrogen and high-purity oxygen were continuously produced using the gas purification means 300 of Fig. 4 as the oxygen purification means 35 of Fig. 1. The hydrogen purification means 37 of Fig. 1 is similar to the gas purification means 300 of Fig. 4, but is configured such that the feed gas 310 is not supplied to the degassing means 32.

[0060] Both the oxygen purification means 35 and the hydrogen purification means 37 were used as regeneration gas in the adsorption-type purification device 135, and the amount of gas supplied as regeneration gas to the adsorption-type dehumidification device 131 was 3% of the amount of gas generated in the electrolysis means 33. Furthermore, both the oxygen purification means 35 and the hydrogen purification means 37 were used as regeneration gas in the adsorption-type dehumidification device 131, and the amount of gas used as regeneration gas in the adsorption-type dehumidification device 131 was 10%, which was the sum of the aforementioned 3% and the amount of gas generated in the electrolysis means 33. The degassing means 32 was supplied with gas that had passed through the adsorption tower as regeneration gas in the oxygen gas adsorption-type dehumidification device 131.

[0061] The inlet pressure of the oxygen purification means 35 was 0.8 MPa and 25°C, and the impurity components contained in the oxygen gas 6 at the inlet were saturated moisture and 3 ppm hydrogen, and the nitrogen and carbon dioxide contents were 0.1 ppm or less. The inlet pressure of the hydrogen purification means 37 was 0.8 MPa and 25°C, and the impurity components contained in the hydrogen gas 10 at the inlet were saturated moisture and 1 ppm or less oxygen, and the nitrogen and carbon dioxide contents were 0.1 ppm or less.

[0062] The oxygen gas obtained at the outlet of the oxygen purification means 35 contained 0.1 ppm or less of hydrogen, nitrogen, moisture, and carbon dioxide. The hydrogen gas obtained at the outlet of the hydrogen purification means 37 contained 0.1 ppm or less of oxygen, nitrogen, moisture, and carbon dioxide.

[0063] (Comparative Example 1) The degassing means 32 in Figure 1 was omitted, and the oxygen purification means 35 and hydrogen purification means 37 were similar to the gas purification means 100 in Figure 2, but in both cases the regeneration exhaust gas 109 was not supplied to the degassing means 32, thereby continuously producing high-purity hydrogen and high-purity oxygen.

[0064] In both the oxygen purification means 35 and the hydrogen purification means 37, the amount of gas used as regeneration gas in the adsorption-type purification device 135 was 3% of the amount of gas generated in the electrolysis means 33. In addition, in both the oxygen purification means 35 and the hydrogen purification means 37, the amount of exhaust gas used as regeneration gas in the adsorption-type dehumidification device 131 and released into the atmosphere was 10% of the amount of gas generated in the electrolysis means 33.

[0065] The inlet of oxygen purification means 35 was at 0.8 MPa and 25°C, and the impurities contained in oxygen gas 6 at the inlet were saturated moisture, 3 ppm hydrogen, 20 ppm nitrogen, and 0.5 ppm carbon dioxide. The inlet of hydrogen purification means 37 was at 0.8 MPa and 25°C, and the impurities contained in hydrogen gas 10 at the inlet were saturated moisture, less than 1 ppm oxygen, 3 ppm nitrogen, and 0.1 ppm carbon dioxide.

[0066] In the oxygen gas obtained at the outlet of the oxygen purification means 35, the contents of hydrogen, moisture, and carbon dioxide were all 0.1 ppm or less, but the nitrogen content was 20 ppm, the same as that at the inlet of the oxygen purification means 35. Similarly, in the hydrogen gas obtained at the outlet of the hydrogen purification means 37, the contents of oxygen, moisture, and carbon dioxide were all 0.1 ppm or less, but the nitrogen content was 3 ppm, the same as that at the inlet of the hydrogen purification means 37.

[0067] (Comparative Example 2) The oxygen purification means 35 in Figure 1 is similar to the gas purification means 100 in Figure 2, but is configured so that the regeneration exhaust gas 109 is not supplied to the degassing means 32, while the hydrogen purification means 37 in Figure 1 is configured so that the regeneration exhaust gas 109 is supplied to the degassing means 32, similar to the gas purification means 100 in Figure 2, thereby continuously producing high-purity hydrogen and high-purity oxygen.

[0068] In both the oxygen purification means 35 and the hydrogen purification means 37, the amount of gas used as regeneration gas in the adsorption-type purification device 135 was 3% of the amount of gas generated in the electrolysis means 33. In addition, in both the oxygen purification means 35 and the hydrogen purification means 37, the amount of exhaust gas used as regeneration gas in the adsorption-type dehumidification device 131 and released into the atmosphere was 10% of the amount of gas generated in the electrolysis means 33. The degassing means 32 was supplied with gas that had passed through the adsorption tower as regeneration gas in the hydrogen gas adsorption-type purification device 135.

[0069] The inlet pressure of the oxygen purification means 35 was 0.8 MPa and 25°C, and the impurity components contained in the oxygen gas 6 at the inlet were saturated moisture and 25 ppm of hydrogen, and the nitrogen and carbon dioxide contents were 0.1 ppm or less. The inlet pressure of the hydrogen purification means 37 was 0.8 MPa and 25°C, and the impurity components contained in the hydrogen gas 10 at the inlet were saturated moisture and 1 ppm or less of oxygen, and the nitrogen and carbon dioxide contents were 0.1 ppm or less.

[0070] In Comparative Example 2, a catalytic reactor was provided with a larger catalyst loading than in Example 1, and as a result, the contents of hydrogen, nitrogen, moisture, and carbon dioxide in the oxygen gas obtained at the outlet of the oxygen purification means 35 were all 0.1 ppm or less. Also, the contents of oxygen, nitrogen, moisture, and carbon dioxide in the hydrogen gas obtained at the outlet of the hydrogen purification means 37 were all 0.1 ppm or less.

[0071] From the above, comparing Example 1 with Comparative Example 1, it can be seen that providing a degassing means enables purification to a higher purity. Also, comparing Example 1 with Comparative Example 2, it can be seen that supplying oxygen gas to the degassing means enables more efficient generation of oxygen and hydrogen.

[0072] In addition, by comparing Example 1 and Example 2, it can be understood that by reusing the regeneration gas used in the oxygen purification means as the regeneration gas for the adsorption-type dehumidification device and then supplying it to the degassing means for the raw pure water, it becomes possible to increase the amount of usable product gas and thereby achieve efficient production. [Industrial Applicability]

[0073] According to the present invention, high-purity oxygen and high-purity hydrogen can be supplied by water electrolysis to technical fields that require the use of highly purified oxygen and hydrogen, such as the semiconductor industry. [Explanation of symbols]

[0074] 1...raw water, 2,3,4...raw pure water, 5...oxygen, 6,101,102,103,104,105,106,107,301,302,303,304,305,306,307...oxygen gas, 7,11...exhaust gas, 8,108,308...high-purity oxygen gas, 9...hydrogen, 10...hydrogen gas, 12...high-purity hydrogen gas, 30...pure water production means, 31...pure water storage tank, 32...deaeration means, 33...electrolysis means, 34, 36... Gas-liquid separation tank, 35... Oxygen purification means, 37... Hydrogen purification means, 50... Manufacturing apparatus, 100, 300... Gas purification means, 109, 309... Regenerated exhaust gas, 130, 330... Drain removal device, 131, 331... Adsorption type dehumidification device, 132, 332... Heat exchanger, 133, 333... Heating means, 134, 334... Catalyst tower, 135, 335... Adsorption type purification device, 200... Adsorption device, 201... Purification raw material Feed gas, 202... purified gas, 203... regeneration gas, 204... exhaust gas, 211, 241... purified feed gas inlet pipe, 212, 245, 251... purified gas outlet pipe, 213, 243... regeneration gas inlet pipe, 214, 242... exhaust gas outlet pipe, 230a, 230b... adsorption tower, 231a, 231b... purified feed gas inlet valve, 232a, 232b... exhaust gas outlet valve, 233a, 233b... regeneration gas Introduction valves, 234a, 234b...pressurized gas introduction piping valves, 235a, 235b...purified gas outlet valves, 236...regenerated cooling gas introduction valve, 237...regenerated heating gas introduction valve, 238...regenerated gas heating heater, 240a, 240b...adsorption tower inlet side, 244, 252...pressurized gas piping, 246...regenerated cooling gas introduction piping, 247...regenerated heating gas introduction piping, 250a, 250b...adsorption tower outlet side, 310...supply gas.

Claims

1. A degassing process for the raw pure water; an electrolysis step of generating oxygen and hydrogen by water electrolysis using a polymer electrolyte membrane; a purification step of oxygen generated by the electrolysis step; a step of purifying hydrogen generated by the electrolysis step; A method for producing high-purity hydrogen and high-purity oxygen, comprising a step of supplying a purge gas, which has been passed through during regeneration of the adsorbent used in the oxygen purification step, to a step of degassing raw pure water.

2. 2. The method for producing high-purity hydrogen and high-purity oxygen according to claim 1, wherein the flow rate of the purge gas supplied to the degassing step is adjusted according to the flow rate of oxygen generated in the electrolysis step and / or the flow rate of hydrogen generated in the electrolysis step.

3. a means for degassing the raw pure water; an electrolysis means for generating oxygen and hydrogen by water electrolysis using a polymer electrolyte membrane; a means for purifying oxygen generated by the electrolysis means; a means for purifying hydrogen generated by the electrolysis means; A high-purity hydrogen and high-purity oxygen production apparatus comprising a means for supplying a purge gas, which has been passed through during regeneration of the adsorbent used in the oxygen purification means, to the degassing means for raw pure water.

4. 4. The apparatus for producing high-purity hydrogen and high-purity oxygen according to claim 3, wherein the flow rate of the purge gas supplied to the degassing means is adjusted in accordance with the flow rate of oxygen generated by the electrolysis means and / or the flow rate of hydrogen generated by the electrolysis means.

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