WO2018056203A1 - Method for purifying hydrogen or helium gas, and apparatus for purifying hydrogen or helium gas - Google Patents

Method for purifying hydrogen or helium gas, and apparatus for purifying hydrogen or helium gas Download PDF

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WO2018056203A1
WO2018056203A1 PCT/JP2017/033430 JP2017033430W WO2018056203A1 WO 2018056203 A1 WO2018056203 A1 WO 2018056203A1 JP 2017033430 W JP2017033430 W JP 2017033430W WO 2018056203 A1 WO2018056203 A1 WO 2018056203A1
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gas
adsorbent
adsorption tower
adsorption
hydrogen
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PCT/JP2017/033430
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French (fr)
Japanese (ja)
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光利 中谷
沙織 田中
貴裕 土屋
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住友精化株式会社
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Priority to CN201780058840.5A priority Critical patent/CN109789368A/en
Priority to JP2018541039A priority patent/JP6979023B2/en
Priority to KR1020197009111A priority patent/KR102391642B1/en
Publication of WO2018056203A1 publication Critical patent/WO2018056203A1/en
Priority to PH12019500649A priority patent/PH12019500649A1/en

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
    • B01D53/02—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols by adsorption, e.g. preparative gas chromatography
    • B01D53/04—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols by adsorption, e.g. preparative gas chromatography with stationary adsorbents
    • B01D53/047—Pressure swing adsorption
    • B01D53/053—Pressure swing adsorption with storage or buffer vessel
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B23/00—Noble gases; Compounds thereof
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B3/00—Hydrogen; Gaseous mixtures containing hydrogen; Separation of hydrogen from mixtures containing it; Purification of hydrogen
    • C01B3/50—Separation of hydrogen or hydrogen containing gases from gaseous mixtures, e.g. purification
    • C01B3/56—Separation of hydrogen or hydrogen containing gases from gaseous mixtures, e.g. purification by contacting with solids; Regeneration of used solids

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  • the power cost for applying the vacuum is high. Further, in the method using a high-purity product gas purified as a purge gas for regenerative cleaning, the cost is increased due to the use of the product gas. Furthermore, the regeneration by heating also leads to an increase in cost for the energy required for heating.
  • the present invention has been conceived under such circumstances, using a pressure fluctuation adsorption method, while reducing costs from a raw material gas containing hydrocarbon gas or volatile hydrocarbon as an impurity. It is an object of the present invention to provide a method and an apparatus suitable for obtaining high-purity hydrogen or helium.
  • hydrocarbon gas or volatile as impurities can be obtained by repeating the cycle of the pressure fluctuation adsorption method performed using three or more adsorption towers filled with an adsorbent for each adsorption tower.
  • a method for purifying hydrogen or helium from a source gas containing at least one of hydrocarbons and containing hydrogen or helium as a main component In the cycle, in the state where the adsorption tower is at a predetermined high pressure, the raw material gas is introduced into the adsorption tower, and at least one of the hydrocarbon gas or volatile hydrocarbon in the raw material gas is used as the adsorbent.
  • An adsorption process for adsorbing and discharging a product gas having a high hydrogen or helium concentration from the adsorption tower, and a gas remaining in the tower from the adsorption tower after the adsorption process is exhausted to lower the pressure in the tower A depressurization step, a desorption step in which at least one of the hydrocarbon gas or volatile hydrocarbon is desorbed from the adsorbent in the adsorption tower after the depressurization step and the gas in the column is discharged, and the other in the depressurization step And a cleaning step of introducing the gas discharged from the adsorption tower into the adsorption tower after the desorption step and discharging the gas remaining in the tower.
  • the source gas contains hydrogen sulfide as an impurity.
  • the first region is filled with a silica gel-based first adsorbent having a filling ratio in the range of 15 to 65 vol%.
  • the first region is filled with an activated carbon-based second adsorbent having a filling ratio in the range of 10 to 50 vol%.
  • the third region is filled with a zeolite-based third adsorbent having a filling ratio in the range of 25 to 75 vol%.
  • the source gas contains hydrogen sulfide as an impurity.
  • the first adsorbent is made of hydrophilic silica gel.
  • the present inventors diligently studied a method for separating hydrogen or helium from a source gas containing hydrocarbon gas or volatile hydrocarbon and hydrogen sulfide as impurities by the pressure fluctuation adsorption method.
  • silica gel which is an adsorbent
  • activated carbon which is an adsorbent that does not adsorb volatile hydrocarbons
  • the desorption process is completed using a relatively clean gas in the zeolite layer.
  • the present invention it is possible to purify the content of plural kinds of hydrocarbons contained as impurities in hydrogen or helium to 1 volppm or less and hydrogen sulfide to 0.2 ppb or less at low cost and in a space-saving device.
  • FIG. 1 shows a schematic configuration of a purification apparatus X that can be used for carrying out the method for purifying hydrogen or helium according to the present invention.
  • the purification apparatus X includes three adsorption towers 10A, 10B, and 10C, a raw material gas supply source 21, a product storage tank 22, an offgas tank 23, a cooler 24, a gas-liquid separator 25, and lines 31 to 35.
  • the purification apparatus X is configured to be capable of concentrating and separating hydrogen or helium from a source gas containing hydrogen or helium (crude hydrogen or crude helium) using a pressure fluctuation adsorption method (PSA method).
  • PSA method pressure fluctuation adsorption method
  • the raw material gas there can be mentioned a gas mainly containing hydrogen produced from organic hydride and containing impurities such as hydrocarbon gas, volatile hydrocarbon and hydrogen sulfide.
  • the hydrocarbon gas means a hydrocarbon which has 4 or less carbon atoms and is a gas at normal temperature and pressure, and includes, for example, methane, ethane, propane, butane, ethylene, butylene, propylene and the like.
  • the volatile hydrocarbon refers to a hydrocarbon having 5 to 18 carbon atoms and liquid at normal temperature and pressure, and includes, for example, toluene, cyclohexane, methylcyclohexane, benzene and the like.
  • the present invention can also be applied to the case where the main component of the source gas is helium. Further, the following description will be made on the case where hydrocarbon gas, volatile hydrocarbon, and hydrogen sulfide are included as impurities. However, the present invention may be any one of hydrocarbon gas and volatile hydrocarbon, or hydrocarbon gas as impurities. It is also applicable to the case where any one of volatile hydrocarbons and hydrogen sulfide is included.
  • An adsorbent 132 and a third adsorbent 133 are sequentially stacked.
  • an adsorbent having a property of preferentially adsorbing volatile hydrocarbons is used.
  • adsorbents include silica gel-based adsorbents (hydrophilic silica gel, hydrophobic silica gel, etc.), among which hydrophilic silica gel, particularly silica gel B type is preferable.
  • hydrophilic silica gel particularly silica gel B type is preferable.
  • second and third adsorbents 132 and 133 adsorbents having relatively low adsorbability for volatile hydrocarbons are used.
  • the second adsorbent 132 one having the property of preferentially adsorbing hydrogen sulfide is used.
  • Examples of such an adsorbent include activated carbon derived from coconut shell or coal.
  • As the 3rd adsorption agent 133 what has the property to adsorb hydrocarbon gas preferentially is used.
  • Examples of such adsorbents include zeolite-based adsorbents (A-type zeolite, CaA-type zeolite, Y-type zeolite, etc.), among which CaA-type zeolite is preferable. These adsorbents are generally commercially available, are readily available, and do not require pretreatment.
  • Silica gel (or silica) is inherently hydrophilic because it has a hydroxyl group on the surface, and becomes hydrophobic when subjected to a hydrophobizing treatment such as high temperature heating or reaction with an alkylsilylating agent. Conventionally, this hydrophobization treatment has been a cause of cost increase.
  • the product storage tank 22 is a pressure vessel for storing gas (product gas described later) discharged from the gas passage port 12 of the adsorption towers 10A, 10B, and 10C.
  • the line 34 is for supplying a part of product gas flowing through the line 33 (main trunk line 33 ′) to the adsorption towers 10 A, 10 B, 10 C, and is connected to the main path 33 ′ of the line 33.
  • An automatic valve 341 and a flow rate adjustment valve 342 are provided on the main trunk line 34 '.
  • Automatic valves 34a, 34b, 34c are provided in the branch paths 34A, 34B, 34C.
  • each of the adsorption towers 10A, 10B, and 10C includes an adsorption process, a pressure reduction process, a pressure equalization process (decompression), a desorption process, a cleaning process, a pressure equalization process (pressure increase), and a pressure increase process.
  • adsorption process DP Depressurization process
  • DS Desorption process
  • RN Cleaning process
  • PR Pressure increase process
  • Eq-DP Pressure equalization pressure reduction process
  • Eq-PR Pressure equalization pressure increase process
  • step 1 the automatic valves 31a, 33a, 32b, 34b, 35c, 351 and the flow rate adjusting valve 352 are opened, and the gas flow state as shown in FIG. 2a is achieved.
  • step 2 the adsorption step is continued in the adsorption tower 10A. Also in step 2, the gas passage ports 12 of the adsorption towers 10B and 10C communicate with each other via lines 34 and 35, respectively. On the other hand, the automatic valve 32b is closed for the adsorption tower 10B. At the start of step 2, the pressure in the adsorption tower 10C is still higher than that in the adsorption tower 10B. Therefore, pressure equalization / pressure reduction is performed in the adsorption tower 10C, and pressure equalization / pressure increase is performed in the adsorption tower 10B.
  • the gas in the adsorption tower 10C is introduced into the adsorption tower 10B via the lines 35 and 34, the pressure in the adsorption tower 10C is reduced, and the pressure in the adsorption tower 10B is increased. .
  • the operation time in step 2 is, for example, about 15 seconds.
  • Steps 7 to 9 the operation performed on the adsorption tower 10A in Steps 1 to 3 is performed on the adsorption tower 10C, and the operation performed on the adsorption tower 10B in Steps 1 to 3 is performed.
  • the operation performed on the adsorption tower 10A and the operation performed on the adsorption tower 10C in steps 1 to 3 are performed on the adsorption tower 10B.
  • the filling ratio of the first adsorbent 131 is less than 15 vol%, volatile hydrocarbons may not be sufficiently removed.
  • the filling ratio of the first adsorbent 131 exceeds 75 vol%, the ratio of the cleaning gas remaining in the third adsorbent 133 decreases, the amount of cleaning gas decreases, and the cleaning in the cleaning process becomes insufficient. There is a fear.
  • the filling ratio of the second adsorbent 132 is less than 10 vol%, hydrogen sulfide may not be sufficiently removed.
  • the cleaning gas exhausted from the adsorption tower in the depressurization process after completion of the adsorption process and used for cleaning other adsorption towers in the desorption process after completion of the desorption process is Hydrogen desorbed from the third adsorbent 133 is added to the concentrated hydrogen gas remaining in the gas (mainly the gas in the filling region of the third adsorbent 133 close to the gas passage port 12).
  • the other adsorption tower after the completion of the desorption process can be effectively cleaned using the cleaning gas having an increased hydrogen content.
  • the present invention is not limited to these embodiments, and various modifications can be made without departing from the spirit of the invention.
  • a configuration different from the above-described embodiment may be adopted for the configuration of the line (pipe) forming the gas flow path in the apparatus for carrying out the method for purifying hydrogen or helium according to the present invention.
  • the number of adsorption towers is not limited to the three-column type shown in the above embodiment, and the same effect can be expected even when there are four or more towers.
  • adsorption towers 10A, 10B, and 10C cylindrical ones having an inner diameter of 35 mm were used, and the adsorbent filling capacity was about 1 L (liter).
  • silica gel B type Fluji Silica Silica B type manufactured by Fuji Silysia Chemical Co.
  • Activated carbon as 132 PGAR manufactured by Caterer
  • CaA-type zeolite 5AHP manufactured by Union Showa
  • Example 2 The same as in Example 1 except that the adsorbent filling ratio (volume ratio) was 10 vol% for the first adsorbent 131, 10 vol% for the second adsorbent 132, and 80 vol% for the third adsorbent 133. Hydrogen was purified from the source gas. Moreover, when the impurity concentration in the obtained concentrated hydrogen gas (product gas) was measured with a hydrogen flame ion detector (FID) and a flame photometric detector (FPD), the toluene concentration in the product gas was 3000 volppm, and the methane concentration was The 0.01 volppm, hydrogen sulfide concentration was below the lower limit of quantification (0.1 volppb or less), and the hydrogen gas recovery rate was 70%. The results of this comparative example are shown in Table 1.
  • FID hydrogen flame ion detector
  • FPD flame photometric detector

Abstract

In this method for purifying a hydrogen or helium gas using the PSA method, in which adsorption columns (10A-10C) filled with adsorbents are used to purify a feed gas which contains at least one of a hydrocarbon gas or a volatile hydrocarbon as an impurity and contains a hydrogen or helium gas as a main component, a cycle including an adsorption step, a decompression step, a desorption step, and a washing step is repeatedly performed. Each adsorption column is divided into a first zone, a second zone, and a third zone, in order, from the upstream side to the downstream side in the flow direction of the feed gas in the adsorption column. The first zone is filled with a first silica gel-based adsorbent (131), the filling ratio thereof being in the range of 15-65 vol% with respect to the total filling capacity of the adsorbent. The second zone is filled with a second activated carbon-based adsorbent (132), the filling ratio thereof being in the range of 10-50 vol%. The third zone is filled with a third zeolite-based adsorbent (133), the filling ratio thereof being in the range of 25-75 vol%.

Description

水素またはヘリウムの精製方法、および水素またはヘリウムの精製装置Hydrogen or helium purification method and hydrogen or helium purification apparatus
　本発明は、圧力変動吸着法を利用して水素またはヘリウムを精製するための方法および装置に関する。 The present invention relates to a method and an apparatus for purifying hydrogen or helium using a pressure fluctuation adsorption method.
　公害防止の観点から、廃棄ガスとして放出されるガス中の揮発性炭化水素や硫化水素の濃度は低濃度になるよう規制されている。例えば、ある地域では、トルエンを不純物として含むガスの場合は地上到達点濃度が０．７ｖｏｌｐｐｍ以下に、硫化水素を不純物として含むガスの場合は地上到達点濃度が０．１ｖｏｌｐｐｍ以下に、定められている。そのような規制に対応するための廃棄ガスの処理方法としては、炭化水素の除去については吸収法、冷却法、吸着法、燃焼法などがあり（例えば特許文献１参照）、硫化水素の除去については乾式脱硫、湿式脱硫、および生物脱硫が知られている（例えば特許文献５，６，７参照）。また、それらの処理によって精製した後のガスを回収して再利用する場合もある。また、廃棄ガスの処理設備については、省スペースで且つ、導入費用および稼動費用の安価な方法が求められている。 From the viewpoint of pollution prevention, the concentration of volatile hydrocarbons and hydrogen sulfide in the gas released as waste gas is regulated to be low. For example, in a certain region, the concentration at the ground reaching point is set to 0.7 volppm or less for a gas containing toluene as an impurity, and the concentration at the ground reaching point is set to 0.1 volppm or less for a gas containing hydrogen sulfide as an impurity. Yes. Waste gas treatment methods for complying with such regulations include absorption methods, cooling methods, adsorption methods, and combustion methods for removing hydrocarbons (see, for example, Patent Document 1), and removal of hydrogen sulfide. Is known for dry desulfurization, wet desulfurization, and biological desulfurization (see, for example, Patent Documents 5, 6, and 7). Moreover, the gas after refine | purifying by those processes may be collect | recovered and reused. In addition, for waste gas processing facilities, there is a demand for a space-saving method with low introduction costs and operating costs.
　一方、水素やヘリウムを工業用ガスとして利用する場合、用途によっては、高純度のガスを得るために、精製工程を追加する必要がある。例えば、燃料電池車用の水素の場合、ＩＳＯ１４６８７－２（ＦＣＶ用水素燃料規格，２０１２，ＧｒａｄｅＤ）によれば水素以外の成分の許容濃度として、総炭化水素であれば２ｖｏｌｐｐｍ以下（メタン換算）に、総硫黄成分であれば０．００４ｖｏｌｐｐｍ以下（硫化水素換算）に、する必要がある。この場合においても、省スペースで且つ、安価な方法が求められている。 On the other hand, when hydrogen or helium is used as an industrial gas, it is necessary to add a purification step in order to obtain a high-purity gas depending on the application. For example, in the case of hydrogen for fuel cell vehicles, according to ISO 14687-2 (FCV hydrogen fuel standard, 2012, Grade D), the allowable concentration of components other than hydrogen is 2 volppm or less (in terms of methane) for total hydrocarbons. If it is a total sulfur component, it is necessary to make it 0.004 volppm or less (in terms of hydrogen sulfide). Even in this case, a space-saving and inexpensive method is required.
　炭化水素の除去について、吸収法では、拡散ガス中の炭化水素濃度を１ｖｏｌ％以下にすることは困難であり、未だに実現されていない。冷却法においても、蒸気圧分の不純物が気相側に残留するため、揮発性炭化水素の場合は数ｐｐｍオーダーまで精製することは困難である。燃焼法においては、酸素を混合する必要があり、炭化水素の燃焼により新たに水や二酸化炭素などが生じることから、高純度のガスを得るのには適していない。 Regarding the removal of hydrocarbons, in the absorption method, it is difficult to make the hydrocarbon concentration in the diffusion gas 1 vol% or less, and it has not been realized yet. Even in the cooling method, impurities corresponding to the vapor pressure remain on the gas phase side, so that it is difficult to purify to the order of several ppm in the case of volatile hydrocarbons. In the combustion method, oxygen needs to be mixed, and water, carbon dioxide, and the like are newly generated by combustion of hydrocarbons, and therefore, it is not suitable for obtaining a high-purity gas.
　硫化水素の除去について、乾式脱硫としては、例えば特許文献５に開示されているように、鉄や酸化鉄の粉体、あるいはそれを造粒したペレットを脱硫槽に充填し、その間にガスを流すことにより行われている。しかし、酸化鉄が硫化水素で破過したときは、酸化鉄を除去した後、新しい酸化鉄を乾式脱硫塔に充填しなければならず、装置および保守・管理のための費用が過大なものとなる。湿式脱硫としては、特許文献６に開示されているように、脱硫槽を設け、そこでアルカリ水溶液を散布することにより、アルカリ硫酸塩として回収することが提案されている。この方法ではアルカリ水溶液が必要であり、回収したアルカリ硫酸塩の処理時のｐＨ調整および再利用の問題が残されている。生物脱硫としては、特許文献７に開示されているように硫黄酸化細菌を用いる方法がある。この硫黄酸化細菌を用いる方法では、硫黄分は硫酸として処理水中に含有される。このため、装置の腐食防止、および保守・管理のための費用が過大である等の課題が残っている。また乾式脱硫、湿式脱硫、および生物脱硫等の方法は、トルエンなどの揮発性炭化水素が不純物として含まれる場合、トルエンにより除去性能が低下するという問題もある。 Regarding the removal of hydrogen sulfide, as dry desulfurization, for example, as disclosed in Patent Document 5, iron or iron oxide powder or pellets obtained by granulating the powder are filled in a desulfurization tank, and gas is allowed to flow between them. Has been done. However, when iron oxide breaks through with hydrogen sulfide, after removing the iron oxide, it is necessary to fill the dry desulfurization tower with new iron oxide, resulting in excessive costs for equipment, maintenance and management. Become. As wet desulfurization, as disclosed in Patent Document 6, it is proposed to provide a desulfurization tank and spray an alkaline aqueous solution there to recover it as an alkali sulfate. This method requires an aqueous alkali solution, and there remains a problem of pH adjustment and reuse during the treatment of the recovered alkali sulfate. As biodesulfurization, there is a method using sulfur-oxidizing bacteria as disclosed in Patent Document 7. In this method using sulfur-oxidizing bacteria, the sulfur content is contained in the treated water as sulfuric acid. For this reason, problems remain, such as excessive costs for preventing corrosion of the apparatus and for maintenance and management. In addition, methods such as dry desulfurization, wet desulfurization, and biological desulfurization also have a problem in that when volatile hydrocarbons such as toluene are contained as impurities, the removal performance is reduced by toluene.
　以上のような理由から、高純度の水素やヘリウムを得る方法としては、吸着法が主に用いられている。例えば、ガスに含まれる炭化水素や硫化水素を除去するため、合成ゼオライトや疎水性シリカゲルを使用する圧力変動吸着法が採用される。しかしながら、この方法でも脱着に真空装置を用いることや、シリカリッチのゼオライトやシリカゲルの中でも疎水性のものを使用することから、コスト面で課題があった（例えば特許文献１，４参照）。 For the above reasons, the adsorption method is mainly used as a method for obtaining high-purity hydrogen and helium. For example, in order to remove hydrocarbons and hydrogen sulfide contained in the gas, a pressure fluctuation adsorption method using synthetic zeolite or hydrophobic silica gel is employed. However, this method also has a problem in terms of cost since a vacuum apparatus is used for desorption and a hydrophobic material among silica-rich zeolite and silica gel is used (for example, see Patent Documents 1 and 4).
　また、炭化水素を含む廃棄ガスを圧力変動吸着法を用いて処理し、炭化水素濃度を低減する方法もある。圧力変動吸着法で吸着剤の再生が可能であれば、加熱や冷却は不要となる。しかしながらこの方法においては、脱着時に真空装置が必要であり、さらに吸着剤をあらかじめプレコートすることも必要であり、コスト面や操作の煩雑さの面で課題があった（例えば特許文献２，３参照）。 There is also a method of reducing the hydrocarbon concentration by treating waste gas containing hydrocarbons using a pressure fluctuation adsorption method. If the adsorbent can be regenerated by the pressure fluctuation adsorption method, heating and cooling are unnecessary. However, this method requires a vacuum device at the time of desorption, and also requires pre-coating with an adsorbent in advance, and has problems in terms of cost and complexity of operation (for example, see Patent Documents 2 and 3). ).
　不純物として、複数種の炭化水素（炭化水素ガスや揮発性炭化水素）や硫化水素を含むガスを精製する場合、吸着剤として活性炭を使用する方法が、従来から採用されてきた。活性炭の細孔内に入り込んだ揮発性炭化水素は、容易には脱着されない。このため、脱着に加熱手段を用いる方法が採用されており、温度変動吸着法やスチームの使用により脱着を促している。加熱手段を用いる場合、加熱や冷却に伴う付帯設備を要し、伝熱に時間がかかるなど操作性の面でも課題が多い。 In the case of purifying a gas containing a plurality of types of hydrocarbons (hydrocarbon gas or volatile hydrocarbon) or hydrogen sulfide as impurities, a method of using activated carbon as an adsorbent has been conventionally employed. Volatile hydrocarbons that have entered the pores of the activated carbon are not easily desorbed. For this reason, a method using a heating means is adopted for desorption, and the desorption is promoted by using a temperature fluctuation adsorption method or steam. When a heating means is used, there are many problems in terms of operability, such as requiring incidental facilities for heating and cooling and taking time for heat transfer.
　また、真空再生法を用いた方法では、真空印加のための動力コストがかかる。また、再生洗浄のためのパージガスとして精製された高純度の製品ガスを用いる方法では、製品ガスを使用する分コストアップに繋がる。さらに、加熱による再生についても、同じく加熱に必要なエネルギー分コストアップに繋がる。 Also, in the method using the vacuum regeneration method, the power cost for applying the vacuum is high. Further, in the method using a high-purity product gas purified as a purge gas for regenerative cleaning, the cost is increased due to the use of the product gas. Furthermore, the regeneration by heating also leads to an increase in cost for the energy required for heating.
特開平９－４７６３５号公報Japanese Patent Laid-Open No. 9-47635 特開平１１－７１５８４号公報Japanese Patent Laid-Open No. 11-71584 特開２００４－４２０１３号公報Japanese Patent Laid-Open No. 2004-42013 特表２００５－５２５２２２号公報JP 2005-525222 Gazette 特開２０００－１０２７７９号公報JP 2000-102777 A 特開２００２－２７５４８２号公報JP 2002-275482 A 特開平１１－２６２７９３号公報JP 11-262793 A
　本発明は、このような事情の下で考え出されたものであって、圧力変動吸着法を利用して、不純物として炭化水素ガスや揮発性炭化水素を含む原料ガスから、コストを削減しつつ、高純度な水素またはヘリウムを得るのに適した方法および装置を提供することを課題としている。 The present invention has been conceived under such circumstances, using a pressure fluctuation adsorption method, while reducing costs from a raw material gas containing hydrocarbon gas or volatile hydrocarbon as an impurity. It is an object of the present invention to provide a method and an apparatus suitable for obtaining high-purity hydrogen or helium.
　本発明の第１の側面によれば、吸着剤が充填された３塔以上の吸着塔を用いて行う圧力変動吸着法のサイクルを各吸着塔について繰り返すことにより、不純物として炭化水素ガスまたは揮発性炭化水素の少なくとも一方を含み、且つ主成分として水素またはヘリウムを含む原料ガスから水素またはヘリウムを精製するための方法が提供される。上記サイクルは、上記吸着塔が所定の高圧である状態にて、上記吸着塔に上記原料ガスを導入して当該原料ガス中の上記炭化水素ガスまたは揮発性炭化水素の少なくとも一方を上記吸着剤に吸着させ、当該吸着塔から水素またはヘリウムの濃度が高い製品ガスを排出する吸着工程と、上記吸着工程を終えた上記吸着塔から塔内に残留するガスを排出して塔内の圧力を低下させる減圧工程と、上記減圧工程を終えた上記吸着塔における上記吸着剤から上記炭化水素ガスまたは揮発性炭化水素の少なくとも一方を脱着させ、塔内ガスを排出する脱着工程と、上記減圧工程にある他の吸着塔から排出されたガスを上記脱着工程を終えた上記吸着塔に導入して塔内に残留するガスを排出する洗浄工程と、を含む。上記各吸着塔は、上記吸着塔における上記原料ガスの流れ方向において上流側から下流側に向けて順に第１領域、第２領域および第３領域に区分されている。上記第１領域には、充填比率が１５～６５ｖｏｌ％の範囲であるシリカゲル系の第１吸着剤が充填されている。上記第２領域には、充填比率が１０～５０ｖｏｌ％の範囲である活性炭系の第２吸着剤とが充填されている。上記第３領域には、充填比率が２５～７５ｖｏｌ％の範囲であるゼオライト系の第３吸着剤が充填されている。 According to the first aspect of the present invention, hydrocarbon gas or volatile as impurities can be obtained by repeating the cycle of the pressure fluctuation adsorption method performed using three or more adsorption towers filled with an adsorbent for each adsorption tower. Provided is a method for purifying hydrogen or helium from a source gas containing at least one of hydrocarbons and containing hydrogen or helium as a main component. In the cycle, in the state where the adsorption tower is at a predetermined high pressure, the raw material gas is introduced into the adsorption tower, and at least one of the hydrocarbon gas or volatile hydrocarbon in the raw material gas is used as the adsorbent. An adsorption process for adsorbing and discharging a product gas having a high hydrogen or helium concentration from the adsorption tower, and a gas remaining in the tower from the adsorption tower after the adsorption process is exhausted to lower the pressure in the tower A depressurization step, a desorption step in which at least one of the hydrocarbon gas or volatile hydrocarbon is desorbed from the adsorbent in the adsorption tower after the depressurization step and the gas in the column is discharged, and the other in the depressurization step And a cleaning step of introducing the gas discharged from the adsorption tower into the adsorption tower after the desorption step and discharging the gas remaining in the tower. Each of the adsorption towers is divided into a first area, a second area, and a third area in order from the upstream side to the downstream side in the flow direction of the raw material gas in the adsorption tower. The first region is filled with a silica gel-based first adsorbent having a filling ratio in the range of 15 to 65 vol%. The second region is filled with an activated carbon-based second adsorbent having a filling ratio in the range of 10 to 50 vol%. The third region is filled with a zeolite-based third adsorbent having a filling ratio in the range of 25 to 75 vol%.
　好ましくは、上記原料ガスは、不純物として硫化水素を含む。 Preferably, the source gas contains hydrogen sulfide as an impurity.
　好ましくは、上記第１吸着剤は、親水性シリカゲルよりなる。 Preferably, the first adsorbent is made of hydrophilic silica gel.
　本発明の第２の側面によれば、不純物として炭化水素ガスまたは揮発性炭化水素の少なくとも一方を含み、且つ主成分として水素またはヘリウムを含む原料ガスから水素またはヘリウムを精製するための装置が提供される。当該精製装置は、各々が第１ガス通過口および第２ガス通過口を有し、当該第１および第２ガス通過口の間において吸着剤が充填された３塔以上の吸着塔と、製品ガスを貯留するための貯留タンクと、上記吸着塔の上記第１ガス通過口から排出されるガスを気相成分と液相成分とに分離する気液分離手段と、原料ガス供給源に接続された主幹路、および、上記吸着塔ごとに設けられて当該吸着塔の上記第１ガス通過口側に接続され且つ開閉弁が各々に設けられた複数の分枝路、を有する第１ラインと、上記気液分離手段が設けられた主幹路、および、上記吸着塔ごとに設けられて当該吸着塔の上記第１ガス通過口側に接続され且つ開閉弁が各々に設けられた複数の分枝路、を有する第２ラインと、上記貯留タンクが設けられた主幹路、および、上記吸着塔ごとに設けられて当該吸着塔の上記第２ガス通過口側に接続され且つ開閉弁が各々に設けられた複数の分枝路、を有する第３ラインと、上記第３ラインにおける上記主幹路に接続された主幹路、および、上記吸着塔ごとに設けられて当該吸着塔の上記第２ガス通過口側に接続され且つ開閉弁が各々に設けられた複数の分枝路、を有する第４ラインと、上記第４ラインにおける上記主幹路に接続された主幹路、および、上記吸着塔ごとに設けられて当該吸着塔の上記第２ガス通過口側に接続され且つ開閉弁が各々に設けられた複数の分枝路、を有する第５ラインと、を備えている。上記各吸着塔は、上記吸着塔における上記第１ガス通過口から上記第２ガス通過口に向けて順に第１領域、第２領域および第３領域に区分されている。上記第１領域には、充填比率が１５～６５ｖｏｌ％の範囲であるシリカゲル系の第１吸着剤が充填されている。上記第１領域には、充填比率が１０～５０ｖｏｌ％の範囲である活性炭系の第２吸着剤が充填されている。上記第３領域には、充填比率が２５～７５ｖｏｌ％の範囲であるゼオライト系の第３吸着剤が充填されている。 According to the second aspect of the present invention, there is provided an apparatus for purifying hydrogen or helium from a source gas containing at least one of hydrocarbon gas or volatile hydrocarbon as an impurity and containing hydrogen or helium as a main component. Is done. The purification apparatus includes three or more adsorption towers each having a first gas passage opening and a second gas passage opening and filled with an adsorbent between the first and second gas passage openings, and a product gas. A storage tank for storing the gas, a gas-liquid separation means for separating the gas discharged from the first gas passage port of the adsorption tower into a gas phase component and a liquid phase component, and a source gas supply source A first line having a main path and a plurality of branch paths that are provided for each adsorption tower and are connected to the first gas passage port side of the adsorption tower and each has an on-off valve; and A main passage provided with gas-liquid separation means, and a plurality of branch passages provided for each of the adsorption towers, connected to the first gas passage side of the adsorption tower and provided with on-off valves, A main line provided with the storage tank, and a second line having A third line provided for each of the adsorption towers and connected to the second gas passage side of the adsorption tower and provided with an on-off valve; and a third line of the third line. A main passage connected to the main passage, and a plurality of branch passages provided for each of the adsorption towers and connected to the second gas passage opening side of the adsorption tower and provided with on-off valves. A fourth line, a main path connected to the main path in the fourth line, and a connection provided to each of the adsorption towers on the second gas passage opening side of the adsorption tower, and an on-off valve for each. And a fifth line having a plurality of branch paths provided. Each of the adsorption towers is divided into a first area, a second area, and a third area in order from the first gas passage opening to the second gas passage opening in the adsorption tower. The first region is filled with a silica gel-based first adsorbent having a filling ratio in the range of 15 to 65 vol%. The first region is filled with an activated carbon-based second adsorbent having a filling ratio in the range of 10 to 50 vol%. The third region is filled with a zeolite-based third adsorbent having a filling ratio in the range of 25 to 75 vol%.
　好ましくは、上記原料ガスは、不純物として硫化水素を含む。 Preferably, the source gas contains hydrogen sulfide as an impurity.
　好ましくは、上記第１吸着剤は、親水性シリカゲルよりなる。 Preferably, the first adsorbent is made of hydrophilic silica gel.
　本発明者らは、圧力変動吸着法により不純物として炭化水素ガスや揮発性炭化水素と硫化水素を含む原料ガスから水素またはヘリウムを分離する方法について鋭意検討したところ、揮発性炭化水素を吸着する吸着剤であるシリカゲルの後段に、揮発性炭化水素を吸着させない吸着剤である活性炭およびゼオライトを充填し、吸着工程終了後において、当該ゼオライトの層にある比較的清浄なガスを用いて、脱着工程終了後の吸着塔を洗浄することで、脱着時に真空装置や加熱装置を用いることなく、精製後の高純度の製品ガスを得ることができることを見出し、本発明を完成させるに至った。 The present inventors diligently studied a method for separating hydrogen or helium from a source gas containing hydrocarbon gas or volatile hydrocarbon and hydrogen sulfide as impurities by the pressure fluctuation adsorption method. After the adsorption process, silica gel, which is an adsorbent, is filled with activated carbon, which is an adsorbent that does not adsorb volatile hydrocarbons, and after completion of the adsorption process, the desorption process is completed using a relatively clean gas in the zeolite layer. By washing the subsequent adsorption tower, it was found that a high-purity product gas after purification can be obtained without using a vacuum device or a heating device at the time of desorption, and the present invention has been completed.
　本発明によれば、水素またはヘリウムに不純物として含まれる複数種の炭化水素の含有率を、１ｖｏｌｐｐｍ以下、硫化水素を０．２ｐｐｂ以下まで安価に、且つ省スペースな装置で精製することができる。 According to the present invention, it is possible to purify the content of plural kinds of hydrocarbons contained as impurities in hydrogen or helium to 1 volppm or less and hydrogen sulfide to 0.2 ppb or less at low cost and in a space-saving device.
　本発明のその他の特徴および利点は、添付図面を参照して以下に行う詳細な説明によって、より明らかとなろう。 Other features and advantages of the present invention will become more apparent from the detailed description given below with reference to the accompanying drawings.
本発明の実施形態に係る水素の精製方法を実施するために使用する精製装置の概略構成を表す。The schematic structure of the refiner | purifier used in order to implement the purification method of hydrogen which concerns on embodiment of this invention is represented. 本発明の実施形態に係る水素の精製方法の各ステップにおけるガスの流れ状態を表す。The gas flow state in each step of the method for purifying hydrogen according to the embodiment of the present invention is shown.
　以下、本発明の好ましい実施の形態について、図面を参照して具体的に説明する。 Hereinafter, preferred embodiments of the present invention will be specifically described with reference to the drawings.
　図１は、本発明に係る水素またはヘリウムの精製方法を実施するために使用することができる精製装置Ｘの概略構成を示している。精製装置Ｘは、３塔の吸着塔１０Ａ，１０Ｂ，１０Ｃと、原料ガス供給源２１と、製品貯留タンク２２と、オフガスタンク２３と、冷却器２４と、気液分離器２５と、ライン３１～３５と、を備えている。精製装置Ｘは、水素またはヘリウムを含む原料ガス（粗水素または粗ヘリウム）から圧力変動吸着法（ＰＳＡ法）を利用して水素またはヘリウムを濃縮分離することが可能なように構成されている。原料ガスの例としては、有機ハイドライドを由来として生成された水素を主成分とし、不純物として例えば炭化水素ガス、揮発性炭化水素および硫化水素を含むガスをあげることができる。ここで、炭化水素ガスとは、炭素数が４以下であって常温常圧において気体である炭化水素をいい、例えばメタン、エタン、プロパン、ブタン、エチレン、ブチレン、プロピレン等が含まれる。揮発性炭化水素とは、炭素数が５～１８であって常温常圧において液体である炭化水素をいい、例えばトルエン、シクロヘキサン、メチルシクロヘキサン、ベンゼン等が含まれる。以下の説明は、原料ガスの主成分が水素である場合について行うが、本発明は、原料ガスの主成分がヘリウムである場合にも適用可能である。また、以下の説明は、不純物として炭化水素ガス、揮発性炭化水素および硫化水素を含む場合について行うが、本発明は、不純物として炭化水素ガスおよび揮発性炭化水素のいずれか一方、または炭化水素ガスおよび揮発性炭化水素のいずれか一方と硫化水素とを含む場合も適用可能である。 FIG. 1 shows a schematic configuration of a purification apparatus X that can be used for carrying out the method for purifying hydrogen or helium according to the present invention. The purification apparatus X includes three adsorption towers 10A, 10B, and 10C, a raw material gas supply source 21, a product storage tank 22, an offgas tank 23, a cooler 24, a gas-liquid separator 25, and lines 31 to 35. The purification apparatus X is configured to be capable of concentrating and separating hydrogen or helium from a source gas containing hydrogen or helium (crude hydrogen or crude helium) using a pressure fluctuation adsorption method (PSA method). As an example of the raw material gas, there can be mentioned a gas mainly containing hydrogen produced from organic hydride and containing impurities such as hydrocarbon gas, volatile hydrocarbon and hydrogen sulfide. Here, the hydrocarbon gas means a hydrocarbon which has 4 or less carbon atoms and is a gas at normal temperature and pressure, and includes, for example, methane, ethane, propane, butane, ethylene, butylene, propylene and the like. The volatile hydrocarbon refers to a hydrocarbon having 5 to 18 carbon atoms and liquid at normal temperature and pressure, and includes, for example, toluene, cyclohexane, methylcyclohexane, benzene and the like. The following description will be given for the case where the main component of the source gas is hydrogen, but the present invention can also be applied to the case where the main component of the source gas is helium. Further, the following description will be made on the case where hydrocarbon gas, volatile hydrocarbon, and hydrogen sulfide are included as impurities. However, the present invention may be any one of hydrocarbon gas and volatile hydrocarbon, or hydrocarbon gas as impurities. It is also applicable to the case where any one of volatile hydrocarbons and hydrogen sulfide is included.
　吸着塔１０Ａ，１０Ｂ，１０Ｃの各々は、両端にガス通過口１１，１２を有し、ガス通過口１１，１２の間において、吸着剤が充填されている。具体的には、吸着塔１０Ａ，１０Ｂ，１０Ｃの各々の内部には、例えば多孔板（図示略）によって区画された複数（３つ）の領域が形成されており、これら領域にそれぞれ異なる吸着剤が充填される。本実施形態においては、各吸着塔１０Ａ，１０Ｂ，１０Ｃにおける原料ガスの流れ方向において、上流側（ガス通過口１１）から（ガス通過口１２）下流側に向けて第１吸着剤１３１、第２吸着剤１３２、および第３吸着剤１３３が順に積層されている。 Each of the adsorption towers 10A, 10B, and 10C has gas passage ports 11 and 12 at both ends, and the adsorbent is filled between the gas passage ports 11 and 12. Specifically, inside each of the adsorption towers 10A, 10B, and 10C, for example, a plurality (three) of regions partitioned by a perforated plate (not shown) are formed, and different adsorbents are respectively provided in these regions. Is filled. In the present embodiment, the first adsorbent 131, the second adsorbent 131, the second adsorbent 131, the second adsorbent 131, the second adsorbent 131, the second adsorbent 131, the second adsorbent 131, the second adsorbent 131, and the second adsorbent 131 in the flow direction of the source gas. An adsorbent 132 and a third adsorbent 133 are sequentially stacked.
　第１吸着剤１３１としては、揮発性炭化水素を優先的に吸着する性質を有する吸着剤が用いられる。そのような吸着剤としては、例えばシリカゲル系の吸着剤（親水性シリカゲル、疎水性シリカゲル等）が挙げられ、中でも親水性シリカゲル、とりわけシリカゲルＢ型が好ましい。第２および第３吸着剤１３２，１３３については、揮発性炭化水素の吸着能が相対的に低い吸着剤が用いられる。第２吸着剤１３２としては、硫化水素を優先的に吸着する性質を有するものが用いられる。そのような吸着剤としては、例えば椰子殻由来又は石炭由来の活性炭が挙げられる。第３吸着剤１３３としては、炭化水素ガスを優先的に吸着する性質を有するものが用いられる。そのような吸着剤としては、ゼオライト系の吸着剤（Ａ型ゼオライト、ＣａＡ型ゼオライト、Ｙ型ゼオライト等）が挙げられ、中でもＣａＡ型ゼオライトが好ましい。これらの吸着剤は、一般的に市販され、容易に入手できるものであり、前処理も必要としない。なお、シリカゲル（またはシリカ）は表面に水酸基を有するため元来親水性であり、高温加熱またはアルキルシリル化剤との反応などの疎水化処理を行うことにより疎水性となる。従来はこの疎水化処理がコストアップの原因となっていた。 As the first adsorbent 131, an adsorbent having a property of preferentially adsorbing volatile hydrocarbons is used. Examples of such adsorbents include silica gel-based adsorbents (hydrophilic silica gel, hydrophobic silica gel, etc.), among which hydrophilic silica gel, particularly silica gel B type is preferable. For the second and third adsorbents 132 and 133, adsorbents having relatively low adsorbability for volatile hydrocarbons are used. As the second adsorbent 132, one having the property of preferentially adsorbing hydrogen sulfide is used. Examples of such an adsorbent include activated carbon derived from coconut shell or coal. As the 3rd adsorption agent 133, what has the property to adsorb hydrocarbon gas preferentially is used. Examples of such adsorbents include zeolite-based adsorbents (A-type zeolite, CaA-type zeolite, Y-type zeolite, etc.), among which CaA-type zeolite is preferable. These adsorbents are generally commercially available, are readily available, and do not require pretreatment. Silica gel (or silica) is inherently hydrophilic because it has a hydroxyl group on the surface, and becomes hydrophobic when subjected to a hydrophobizing treatment such as high temperature heating or reaction with an alkylsilylating agent. Conventionally, this hydrophobization treatment has been a cause of cost increase.
　また、第１ないし第３吸着剤１３１，１３２，１３３は、吸着剤の充填容量全体に対して所定の充填比率（体積割合）となるように調整されている。具体的には、第１吸着剤１３１の充填比率が１５～６５ｖｏｌ％、好ましくは１５～５０ｖｏｌ％の範囲とされ、第２吸着剤１３２の充填比率が１０～５０ｖｏｌ％、好ましくは１０～４５ｖｏｌ％の範囲とされ、第３吸着剤１３３の充填比率が２５～７５ｖｏｌ％、好ましくは２５～６５ｖｏｌ％の範囲とされている。そして、これら第１ないし第３吸着剤１３１，１３２，１３３それぞれの充填比率の合計は１００ｖｏｌ％である。 In addition, the first to third adsorbents 131, 132, and 133 are adjusted to have a predetermined filling ratio (volume ratio) with respect to the entire filling capacity of the adsorbent. Specifically, the filling ratio of the first adsorbent 131 is in the range of 15 to 65 vol%, preferably 15 to 50 vol%, and the filling ratio of the second adsorbent 132 is 10 to 50 vol%, preferably 10 to 45 vol%. The filling ratio of the third adsorbent 133 is 25 to 75 vol%, preferably 25 to 65 vol%. The total filling ratio of each of the first to third adsorbents 131, 132, 133 is 100 vol%.
　原料ガス供給源２１は、吸着塔１０Ａ，１０Ｂ，１０Ｃ内に供給する原料ガスを貯留するための圧力容器である。原料ガスに含まれる不純物（炭化水素ガス、揮発性炭化水素、硫化水素）の濃度は特に限定されないが、水素またはヘリウムの圧力と揮発性炭化水素の濃度によっては、配管内で揮発性炭化水素が液化するおそれがある。したがって、原料ガス供給源２１から吸着塔１０Ａ，１０Ｂ，１０Ｃに至るまでの配管（後述するライン３１の主幹路３１’）は加温したり、および／または、吸着塔１０Ａ，１０Ｂ，１０Ｃ手前の主幹路３１’にミストトラップ等を設置したりすることが好ましい。原料ガス供給源２１から供給される原料ガスの圧力は特に限定しないが、高圧であるほど好ましく、必要に応じて主幹路３１’に圧縮機（図示略）を設置する。また、原料ガス供給源２１から供給される水素またはヘリウムに、不純物として水が含まれる場合には、ライン３１の主幹路３１’に水分除去装置（図示略）を設置することが好ましい。ＰＳＡ法による操作温度は特に限定されず、例えば１０～４０℃程度とされる。ただし、上述のように揮発性炭化水素が液化しない程度の温度（常温程度以上）であることが好ましい。 The source gas supply source 21 is a pressure vessel for storing source gas supplied into the adsorption towers 10A, 10B, and 10C. The concentration of impurities (hydrocarbon gas, volatile hydrocarbon, hydrogen sulfide) contained in the source gas is not particularly limited, but depending on the pressure of hydrogen or helium and the concentration of volatile hydrocarbon, May liquefy. Therefore, the piping (main trunk 31 'of the line 31 described later) from the source gas supply source 21 to the adsorption towers 10A, 10B, 10C is heated and / or before the adsorption towers 10A, 10B, 10C. It is preferable to install a mist trap or the like on the main road 31 '. The pressure of the source gas supplied from the source gas supply source 21 is not particularly limited, but is preferably as high as possible. A compressor (not shown) is installed in the main trunk path 31 ′ as necessary. In addition, when hydrogen or helium supplied from the source gas supply source 21 contains water as an impurity, it is preferable to install a moisture removing device (not shown) on the main trunk line 31 ′ of the line 31. The operating temperature by the PSA method is not particularly limited and is, for example, about 10 to 40 ° C. However, it is preferable that the temperature is such that volatile hydrocarbons do not liquefy as described above (normal temperature or higher).
　製品貯留タンク２２は、吸着塔１０Ａ，１０Ｂ，１０Ｃのガス通過口１２から排出されるガス（後述の製品ガス）を貯留するための圧力容器である。 The product storage tank 22 is a pressure vessel for storing gas (product gas described later) discharged from the gas passage port 12 of the adsorption towers 10A, 10B, and 10C.
　オフガスタンク２３は、吸着塔１０Ａ，１０Ｂ，１０Ｃのガス通過口１１から排出されるオフガスを貯留するための圧力容器である。 The off-gas tank 23 is a pressure vessel for storing off-gas discharged from the gas passage ports 11 of the adsorption towers 10A, 10B, and 10C.
　冷却器２４は、オフガスを冷却する。気液分離器２５は、冷却器２４を経たオフガスを所定の圧力下で凝縮して気相成分と液相成分とに分離する。「気液分離手段」なる用語には、上記冷却器２４および上記気液分離器２５が含まれる。 The cooler 24 cools off gas. The gas-liquid separator 25 condenses the off-gas that has passed through the cooler 24 under a predetermined pressure to separate it into a gas phase component and a liquid phase component. The term “gas-liquid separation means” includes the cooler 24 and the gas-liquid separator 25.
　ライン３１は、原料ガス供給源２１が接続される主幹路３１’、および吸着塔１０Ａ，１０Ｂ，１０Ｃの各ガス通過口１１側に各々が接続された分枝路３１Ａ，３１Ｂ，３１Ｃを有する。分枝路３１Ａ，３１Ｂ，３１Ｃには、開状態と閉状態との間で自動的に切替可能な弁（以下、このような機能を有する弁を「自動弁」と称す）３１ａ，３１ｂ，３１ｃが設けられている。 The line 31 has a main path 31 ′ to which the source gas supply source 21 is connected, and branch paths 31 </ b> A, 31 </ b> B, and 31 </ b> C each connected to the gas passage 11 side of the adsorption towers 10 </ b> A, 10 </ b> B, and 10 </ b> C. The branch paths 31A, 31B, and 31C include valves that can be automatically switched between an open state and a closed state (hereinafter, valves having such a function are referred to as “automatic valves”) 31a, 31b, and 31c. Is provided.
　ライン３２は、冷却器２４および気液分離器２５が設けられた主幹路３２’、および、吸着塔１０Ａ，１０Ｂ，１０Ｃの各ガス通過口１１側に各々が接続された分枝路３２Ａ，３２Ｂ，３２Ｃを有する。また、主幹路３２’には、冷却器２４よりも上流側にオフガスタンク２３が設けられている。主幹路３２’におけるオフガスタンク２３と冷却器２４との間には、圧力調節弁３２１が設けられている。分枝路３２Ａ，３２Ｂ，３２Ｃには、自動弁３２ａ，３２ｂ，３２ｃが設けられている。 The line 32 includes a main path 32 ′ provided with the cooler 24 and the gas-liquid separator 25, and branch paths 32A and 32B each connected to the gas passage 11 side of the adsorption towers 10A, 10B, and 10C. , 32C. Further, an off-gas tank 23 is provided on the main trunk path 32 ′ on the upstream side of the cooler 24. A pressure control valve 321 is provided between the off-gas tank 23 and the cooler 24 in the main trunk path 32 ′. Automatic valves 32a, 32b, and 32c are provided in the branch paths 32A, 32B, and 32C.
　ライン３３は、製品貯留タンク２２が設けられた主幹路３３’、および、吸着塔１０Ａ，１０Ｂ，１０Ｃの各ガス通過口１２側に各々が接続された分枝路３３Ａ，３３Ｂ，３３Ｃを有する。分枝路３３Ａ，３３Ｂ，３３Ｃには、自動弁３３ａ，３３ｂ，３３ｃが設けられている。主幹路３３’における製品貯留タンク２２の下流側には、圧力調節弁３３１が設けられている。 The line 33 includes a main path 33 ′ in which the product storage tank 22 is provided, and branch paths 33 A, 33 B, and 33 C each connected to the gas passage 12 side of the adsorption towers 10 A, 10 B, and 10 C. Automatic valves 33a, 33b, and 33c are provided in the branch paths 33A, 33B, and 33C. A pressure regulating valve 331 is provided downstream of the product storage tank 22 in the main trunk path 33 ′.
　ライン３４は、ライン３３（主幹路３３’）を通流する製品ガスの一部を吸着塔１０Ａ，１０Ｂ，１０Ｃに供給するためのものであり、ライン３３の主幹路３３’に接続された主幹路３４’、および、吸着塔１０Ａ，１０Ｂ，１０Ｃの各ガス通過口１２側に各々が接続された分枝路３４Ａ，３４Ｂ，３４Ｃを有する。主幹路３４’には、自動弁３４１および流量調整弁３４２が設けられている。分枝路３４Ａ，３４Ｂ，３４Ｃには、自動弁３４ａ，３４ｂ，３４ｃが設けられている。 The line 34 is for supplying a part of product gas flowing through the line 33 (main trunk line 33 ′) to the adsorption towers 10 A, 10 B, 10 C, and is connected to the main path 33 ′ of the line 33. The passage 34 'and the branch passages 34A, 34B, 34C connected to the gas passage 12 side of the adsorption towers 10A, 10B, 10C, respectively. An automatic valve 341 and a flow rate adjustment valve 342 are provided on the main trunk line 34 '. Automatic valves 34a, 34b, 34c are provided in the branch paths 34A, 34B, 34C.
　ライン３５は、吸着塔１０Ａ，１０Ｂ，１０Ｃのいずれか２つを互いに接続するためのものであり、ライン３４の主幹路３４’に接続された主幹路３５’、および、吸着塔１０Ａ，１０Ｂ，１０Ｃの各ガス通過口１２側に各々が接続された分枝路３５Ａ，３５Ｂ，３５Ｃを有する。主幹路３５’には、自動弁３５１および流量調整弁３５２が設けられている。分枝路３５Ａ，３５Ｂ，３５Ｃには、自動弁３５ａ，３５ｂ，３５ｃが設けられている。 The line 35 is for connecting any two of the adsorption towers 10A, 10B, and 10C to each other, and the main road 35 'connected to the main road 34' of the line 34, and the adsorption towers 10A, 10B, The branch passages 35A, 35B, and 35C are connected to the 10C gas passage 12 side. An automatic valve 351 and a flow rate adjustment valve 352 are provided on the main trunk path 35 ′. Automatic valves 35a, 35b, and 35c are provided in the branch paths 35A, 35B, and 35C.
　以上のような構成を有する精製装置Ｘを使用して、本発明の実施形態に係る水素の精製方法を実施することができる。精製装置Ｘの稼働時において、自動弁３１ａ～３１ｃ，３２ａ～３２ｃ，３３ａ～３３ｃ，３４ａ～３４ｃ，３５ａ～３５ｃ，３４１，３５１、および流量調整弁３４２，３５２を適宜切り替えることにより、装置内において所望のガスの流れ状態を実現し、以下のステップ１～９からなる１サイクルを繰り返すことができる。本方法の１サイクルにおいては、吸着塔１０Ａ，１０Ｂ，１０Ｃの各々にて、吸着工程、減圧工程、均圧工程（減圧）、脱着工程、洗浄工程、均圧工程（昇圧）、および昇圧工程が行われる。図２ａ～２ｉは、ステップ１～９における精製装置Ｘでのガスの流れ状態を模式的に表したものである。なお、図２ａ～２ｉにおいては、以下の略号を使用している。
　ＡＳ：吸着工程
　ＤＰ：減圧工程
　ＤＳ：脱着工程
　ＲＮ：洗浄工程
　ＰＲ：昇圧工程
　Ｅｑ－ＤＰ：均圧減圧工程
　Ｅｑ－ＰＲ：均圧昇圧工程 The purification apparatus X having the above configuration can be used to carry out the hydrogen purification method according to the embodiment of the present invention. When the refining device X is in operation, the automatic valves 31a to 31c, 32a to 32c, 33a to 33c, 34a to 34c, 35a to 35c, 341, 351, and the flow rate adjusting valves 342, 352 are appropriately switched in the device. A desired gas flow state can be realized and one cycle consisting of the following steps 1 to 9 can be repeated. In one cycle of this method, each of the adsorption towers 10A, 10B, and 10C includes an adsorption process, a pressure reduction process, a pressure equalization process (decompression), a desorption process, a cleaning process, a pressure equalization process (pressure increase), and a pressure increase process. Done. 2a to 2i schematically show the gas flow state in the purification apparatus X in steps 1 to 9. FIG. In FIGS. 2a to 2i, the following abbreviations are used.
AS: Adsorption process DP: Depressurization process DS: Desorption process RN: Cleaning process PR: Pressure increase process Eq-DP: Pressure equalization pressure reduction process Eq-PR: Pressure equalization pressure increase process
　ステップ１では、自動弁３１ａ，３３ａ，３２ｂ，３４ｂ，３５ｃ，３５１および流量調整弁３５２が開かれ、図２ａに示すようなガスの流れ状態が達成される。 In step 1, the automatic valves 31a, 33a, 32b, 34b, 35c, 351 and the flow rate adjusting valve 352 are opened, and the gas flow state as shown in FIG. 2a is achieved.
　吸着塔１０Ａにおいては、原料ガスがライン３１を介してガス通過口１１から導入されて、吸着工程が行われる。吸着工程にある吸着塔１０Ａ内は所定の高圧状態に維持されており、原料ガス中の主に揮発性炭化水素、炭化水素ガスおよび硫化水素が吸着塔１０Ａ内の吸着剤に吸着される。そして、吸着塔１０Ａのガス通過口１２側から水素が濃縮されたガス（製品ガス）が排出される。当該製品ガスは、分枝路３３Ａおよび主幹路３３’を介して製品貯留タンク２２に送出される。なお、製品貯留タンク２２内の製品ガスは、圧力調節弁３３１を介して適宜、系外に取り出されて、所望の用途に利用される。 In the adsorption tower 10A, the raw material gas is introduced from the gas passage port 11 through the line 31, and the adsorption process is performed. The inside of the adsorption tower 10A in the adsorption step is maintained at a predetermined high pressure state, and mainly volatile hydrocarbons, hydrocarbon gas and hydrogen sulfide in the raw material gas are adsorbed by the adsorbent in the adsorption tower 10A. And the gas (product gas) with which hydrogen was concentrated is discharged | emitted from the gas passage 12 side of 10 A of adsorption towers. The product gas is sent to the product storage tank 22 through the branch path 33A and the main trunk path 33 '. Note that the product gas in the product storage tank 22 is appropriately taken out of the system via the pressure control valve 331 and used for a desired application.
　ここで、吸着塔１０Ａに導入される原料ガスにおける不純物（炭化水素ガス、揮発性炭化水素、硫化水素）の濃度について、特に制限はないが、炭化水素ガスおよび揮発性炭化水素は例えば１００ｖｏｌｐｐｍ～１ｖｏｌ％程度、硫化水素は例えば０．１ｖｏｌｐｐｍ～１ｖｏｌｐｐｍ程度とされる。吸着工程にある吸着塔１０Ａの内部の最高圧力（吸着圧力）は、例えば０．１～１．０ＭＰａＧ（Ｇはゲージ圧であることを表し、以下も同じである）であり、好ましくは０．５～０．８ＭＰａＧである。 Here, the concentration of impurities (hydrocarbon gas, volatile hydrocarbon, hydrogen sulfide) in the raw material gas introduced into the adsorption tower 10A is not particularly limited, but the hydrocarbon gas and volatile hydrocarbon are, for example, 100 vol ppm to 1 vol. %, Hydrogen sulfide is, for example, about 0.1 vol ppm to 1 vol ppm. The maximum pressure (adsorption pressure) inside the adsorption tower 10A in the adsorption step is, for example, 0.1 to 1.0 MPaG (G represents a gauge pressure, and the same applies hereinafter), and preferably is 0.1. 5 to 0.8 MPaG.
　また、ステップ１では、吸着塔１０Ｂ，１０Ｃそれぞれのガス通過口１２がライン３４，３５を介して連通している。吸着塔１０Ｂについては先に脱着工程を行っており、吸着塔１０Ｃについては先に吸着工程を行っていたから（図２ｉに示されるステップ９参照）、ステップ１の開始時には、吸着塔１０Ｃが吸着塔１０Ｂよりも塔内の圧力が高い状態にある。そして、ステップ１の開始後において、吸着塔１０Ｃでは減圧工程が行われ、吸着塔１０Ｃの塔内に残留している不純物濃度の低いガス（残留濃縮水素ガス）がガス通過口１２から排出され、塔内圧力が低下する。ステップ１の開始時と終了時における吸着塔１０Ｃの塔内圧力の差は、例えば３００ｋＰａ程度である。一方、吸着塔１０Ｂでは洗浄工程が行われ、吸着塔１０Ｃから排出された残留濃縮水素ガスが、ライン３５、流量調整弁３５２およびライン３４を介して洗浄ガスとしてガス通過口１２から導入され、且つ塔内に残留するガスを排出する。ここで吸着塔１０Ｂから排出されるガスは、不純物（揮発性炭化水素、炭化水素ガス、硫化水素）の濃度の高いガスであり、当該ガスはオフガスとしてライン３２を介してオフガスタンク２３へ送られる。ステップ１の終了時において、吸着塔１０Ｃの塔内圧力は吸着塔１０Ｂの塔内圧力よりも高い。ステップ１の操作時間は、例えば７５秒程度とされる。 In Step 1, the gas passage ports 12 of the adsorption towers 10B and 10C communicate with each other through lines 34 and 35, respectively. Since the desorption process has been performed first for the adsorption tower 10B and the adsorption process has been previously performed for the adsorption tower 10C (see step 9 shown in FIG. 2i), at the start of step 1, the adsorption tower 10C is moved to the adsorption tower 10B. The pressure in the tower is higher than that. Then, after the start of step 1, a depressurization step is performed in the adsorption tower 10C, and a gas having a low impurity concentration (residual concentrated hydrogen gas) remaining in the tower of the adsorption tower 10C is discharged from the gas passage port 12, The pressure inside the tower decreases. The difference in the internal pressure of the adsorption tower 10C at the start and end of Step 1 is, for example, about 300 kPa. On the other hand, a cleaning process is performed in the adsorption tower 10B, and the residual concentrated hydrogen gas discharged from the adsorption tower 10C is introduced as a cleaning gas from the gas passage port 12 via the line 35, the flow rate adjustment valve 352, and the line 34, and The gas remaining in the tower is discharged. Here, the gas discharged from the adsorption tower 10B is a gas having a high concentration of impurities (volatile hydrocarbon, hydrocarbon gas, hydrogen sulfide), and the gas is sent to the offgas tank 23 through the line 32 as an offgas. . At the end of step 1, the pressure in the adsorption tower 10C is higher than the pressure in the adsorption tower 10B. The operation time of step 1 is about 75 seconds, for example.
　ステップ２では、自動弁３１ａ，３３ａ，３４ｂ，３５ｃ，３５１および流量調整弁３５２が開かれ、図２ｂに示すようなガスの流れ状態が達成される。 In step 2, the automatic valves 31a, 33a, 34b, 35c, 351 and the flow rate adjusting valve 352 are opened, and the gas flow state as shown in FIG. 2b is achieved.
　ステップ２では、吸着塔１０Ａにおいて引き続き吸着工程が行われる。また、ステップ２においても、吸着塔１０Ｂ，１０Ｃそれぞれのガス通過口１２がライン３４，３５を介して連通している。一方、吸着塔１０Ｂについては自動弁３２ｂが閉じている。そして、ステップ２の開始時において、吸着塔１０Ｃの塔内の方が吸着塔１０Ｂの塔内よりも依然として高圧となっている。そのため、吸着塔１０Ｃでは均圧減圧が行われ、吸着塔１０Ｂでは均圧昇圧が行われる。より具体的には、吸着塔１０Ｃの塔内ガスがライン３５，３４を介して吸着塔１０Ｂに導入され、吸着塔１０Ｃの塔内が減圧されるとともに、吸着塔１０Ｂの塔内が昇圧される。この結果、吸着塔１０Ｂ，１０Ｃにおいては、内部圧力が実質的に等しくなる。ステップ２での操作時間は、例えば１５秒程度とされる。 In step 2, the adsorption step is continued in the adsorption tower 10A. Also in step 2, the gas passage ports 12 of the adsorption towers 10B and 10C communicate with each other via lines 34 and 35, respectively. On the other hand, the automatic valve 32b is closed for the adsorption tower 10B. At the start of step 2, the pressure in the adsorption tower 10C is still higher than that in the adsorption tower 10B. Therefore, pressure equalization / pressure reduction is performed in the adsorption tower 10C, and pressure equalization / pressure increase is performed in the adsorption tower 10B. More specifically, the gas in the adsorption tower 10C is introduced into the adsorption tower 10B via the lines 35 and 34, the pressure in the adsorption tower 10C is reduced, and the pressure in the adsorption tower 10B is increased. . As a result, the internal pressures are substantially equal in the adsorption towers 10B and 10C. The operation time in step 2 is, for example, about 15 seconds.
　ステップ３では、自動弁３１ａ，３３ａ，３４ｂ，３２ｃ，３４１および流量調整弁３４２が開かれ、図２ｃに示すようなガスの流れ状態が達成される。 In step 3, the automatic valves 31a, 33a, 34b, 32c, 341 and the flow rate adjusting valve 342 are opened, and the gas flow state as shown in FIG. 2c is achieved.
　ステップ３では、吸着塔１０Ａにおいて引き続き吸着工程が行われる。さらに、ステップ３では、吸着塔１０Ｂ，１０Ｃの連通を遮断する一方、吸着塔１０Ａのガス通過口１２から排出された製品ガスの一部をライン３４および流量調整弁３４２を介して吸着塔１０Ｂに導入させ、吸着塔１０Ｂの昇圧工程が行われる。 In step 3, the adsorption step is continued in the adsorption tower 10A. Further, in Step 3, while the communication between the adsorption towers 10B and 10C is cut off, a part of the product gas discharged from the gas passage 12 of the adsorption tower 10A is transferred to the adsorption tower 10B via the line 34 and the flow rate adjusting valve 342. The pressure increasing step of the adsorption tower 10B is performed.
　また、ステップ３では、吸着塔１０Ｃについては、自動弁３２ｃが開かれることでライン３２を介してオフガスタンク２３と連通している。これにより、吸着塔１０Ｃでは脱着工程が行われ、吸着塔１０Ｃの塔内が減圧されて吸着剤から不純物（主に揮発性炭化水素、炭化水素ガス、硫化水素）が脱着され、塔内のガス（不純物濃度が高いガス）がガス通過口１１を通じてオフガスとして塔外へ排出される。脱着工程にある吸着塔１０Ｃの内部の最低圧力（脱着圧力）は、例えば０～５０ｋＰａＧであり、好ましくは０～２０ｋＰａＧである。吸着塔１０Ｃから排出されたオフガスは、ライン３２を介してオフガスタンク２３へ送られる。オフガスタンク２３内のガスは、圧力調節弁３２１を介して適宜、冷却器２４に送られ、さらに気液分離器２５を通過することで揮発性炭化水素は液化され、液相として回収することができる。また、炭化水素ガスについても、気液分離器２５を通過することで気相として回収することができる。ステップ３の操作時間は、例えば１３５秒程度とされる。上記のステップ１～３は、ステップ１～９により構成されるサイクルの１／３に相当し、これらステップ１～３の工程時間は、合計２２５秒程度である。 In Step 3, the adsorption tower 10C communicates with the off-gas tank 23 through the line 32 by opening the automatic valve 32c. Thereby, the desorption process is performed in the adsorption tower 10C, the inside of the adsorption tower 10C is depressurized, and impurities (mainly volatile hydrocarbons, hydrocarbon gas, hydrogen sulfide) are desorbed from the adsorbent, and the gas in the tower (Gas having a high impurity concentration) is discharged out of the tower as an off-gas through the gas passage port 11. The minimum pressure (desorption pressure) inside the adsorption tower 10C in the desorption step is, for example, 0 to 50 kPaG, preferably 0 to 20 kPaG. The off gas discharged from the adsorption tower 10 </ b> C is sent to the off gas tank 23 through the line 32. The gas in the off-gas tank 23 is appropriately sent to the cooler 24 via the pressure control valve 321, and further passes through the gas-liquid separator 25 so that the volatile hydrocarbon is liquefied and recovered as a liquid phase. it can. Also, the hydrocarbon gas can be recovered as a gas phase by passing through the gas-liquid separator 25. The operation time of step 3 is, for example, about 135 seconds. The above steps 1 to 3 correspond to 1/3 of the cycle constituted by steps 1 to 9, and the process time of these steps 1 to 3 is about 225 seconds in total.
　以降のステップ４～６では、図２ｄ～２ｆに示したように、ステップ１～３において吸着塔１０Ａについて行った操作を吸着塔１０Ｂについて行い、ステップ１～３において吸着塔１０Ｂについて行った操作を吸着塔１０Ｃについて行い、ステップ１～３において吸着塔１０Ｃについて行った操作を吸着塔１０Ａについて行う。 In subsequent Steps 4 to 6, as shown in FIGS. 2d to 2f, the operation performed on the adsorption tower 10A in Steps 1 to 3 is performed on the adsorption tower 10B, and the operation performed on the adsorption tower 10B in Steps 1 to 3 is performed. The operation performed on the adsorption tower 10C and the operation performed on the adsorption tower 10C in steps 1 to 3 are performed on the adsorption tower 10A.
　ステップ４では、自動弁３１ｂ，３３ｂ，３２ｃ，３４ｃ，３５ａ，３５１および流量調整弁３５２が開かれ、図２ｄに示すようなガスの流れ状態が達成される。ステップ５では、自動弁３１ｂ，３３ｂ，３４ｃ，３５ａ，３５１および流量調整弁３５２が開かれ、図２ｅに示すようなガスの流れ状態が達成される。ステップ６では、自動弁３１ｂ，３３ｂ，３４ｃ，３２ａ，３４１および流量調整弁３４２が開かれ、図２ｆに示すようなガスの流れ状態が達成される。詳細な説明は省略するが、ステップ４，５，６では、吸着塔１０Ａは、ステップ１，２，３の各ステップにおける吸着塔１０Ｃと同じ操作を順次遂行し、吸着塔１０Ｂは、ステップ１，２，３における吸着塔１０Ａと同じ状態となっており、吸着塔１０Ｃは、ステップ１，２，３における吸着塔１０Ｂと同じ操作を順次遂行する。 In step 4, the automatic valves 31b, 33b, 32c, 34c, 35a, 351 and the flow rate adjusting valve 352 are opened, and the gas flow state as shown in FIG. 2d is achieved. In step 5, the automatic valves 31b, 33b, 34c, 35a, 351 and the flow rate adjusting valve 352 are opened, and the gas flow state as shown in FIG. 2e is achieved. In Step 6, the automatic valves 31b, 33b, 34c, 32a, 341 and the flow rate adjusting valve 342 are opened, and the gas flow state as shown in FIG. 2f is achieved. Although detailed explanation is omitted, in steps 4, 5, and 6, the adsorption tower 10A sequentially performs the same operation as the adsorption tower 10C in each of the steps 1, 2, and 3, and the adsorption tower 10B 2 and 3, the adsorption tower 10C sequentially performs the same operation as the adsorption tower 10B in steps 1, 2, and 3.
　以降のステップ７～９では、図２ｇ～２ｉに示したように、ステップ１～３において吸着塔１０Ａについて行った操作を吸着塔１０Ｃについて行い、ステップ１～３において吸着塔１０Ｂについて行った操作を吸着塔１０Ａについて行い、ステップ１～３において吸着塔１０Ｃについて行った操作を吸着塔１０Ｂについて行う。 In subsequent Steps 7 to 9, as shown in FIGS. 2g to 2i, the operation performed on the adsorption tower 10A in Steps 1 to 3 is performed on the adsorption tower 10C, and the operation performed on the adsorption tower 10B in Steps 1 to 3 is performed. The operation performed on the adsorption tower 10A and the operation performed on the adsorption tower 10C in steps 1 to 3 are performed on the adsorption tower 10B.
　ステップ７では、自動弁３１ｃ，３３ｃ，３２ａ，３４ａ，３５ｂ，３５１および流量調整弁３５２が開かれ、図２ｇに示すようなガスの流れ状態が達成される。ステップ８では、自動弁３１ｃ，３３ｃ，３４ａ，３５ｂ，３５１および流量調整弁３５２が開かれ、図２ｈに示すようなガスの流れ状態が達成される。ステップ９では、自動弁３１ｃ，３３ｃ，３４ａ，３２ｂ，３４１および流量調整弁３４２が開かれ、図２ｉに示すようなガスの流れ状態が達成される。詳細な説明は省略するが、ステップ７，８，９では、吸着塔１０Ａは、ステップ１，２，３の各ステップにおける吸着塔１０Ｂと同じ操作を順次遂行し、吸着塔１０Ｂは、ステップ１，２，３の各ステップにおける吸着塔１０Ｃと同じ操作を順次遂行し、吸着塔１０Ｃは、ステップ１，２，３の各ステップにおける吸着塔１０Ａと同じ操作を順次遂行する。 In step 7, the automatic valves 31c, 33c, 32a, 34a, 35b, 351 and the flow rate adjusting valve 352 are opened, and the gas flow state as shown in FIG. 2g is achieved. In step 8, the automatic valves 31c, 33c, 34a, 35b, 351 and the flow rate adjusting valve 352 are opened, and the gas flow state as shown in FIG. 2h is achieved. In step 9, the automatic valves 31c, 33c, 34a, 32b, 341 and the flow rate adjusting valve 342 are opened, and the gas flow state as shown in FIG. 2i is achieved. Although detailed explanation is omitted, in steps 7, 8, and 9, the adsorption tower 10A sequentially performs the same operation as the adsorption tower 10B in each of the steps 1, 2, and 3, and the adsorption tower 10B The same operation as the adsorption tower 10C in each of the second and third steps is sequentially performed, and the adsorption tower 10C sequentially performs the same operation as the adsorption tower 10A in each of the steps 1, 2, and 3.
　そして、以上のステップ１～９からなるサイクルが吸着塔１０Ａ，１０Ｂ，１０Ｃの各々において繰り返し行われることにより、吸着塔１０Ａ，１０Ｂ，１０Ｃのいずれかに原料ガスが連続的に導入され、且つ、濃縮水素ガス（製品ガス）が連続的に取得される。 The cycle consisting of the above steps 1 to 9 is repeatedly performed in each of the adsorption towers 10A, 10B, and 10C, whereby the raw material gas is continuously introduced into any of the adsorption towers 10A, 10B, and 10C, and Concentrated hydrogen gas (product gas) is continuously obtained.
　本実施形態の水素の精製方法において、吸着塔１０Ａ，１０Ｂ，１０Ｃの各々において実施されるＰＳＡ法による１サイクルについて、吸着工程の後、塔内の残留ガスを脱着工程後の他の吸着塔に導入して、洗浄工程を行う。吸着工程終了後の吸着塔内のガスは不純物濃度の低いガス（残留濃縮水素ガス）であり、当該ガスを用いて脱着工程後の吸着塔を効率よく洗浄することができる。また、製品ガスを洗浄のために用いないので、水素の回収率低下を抑制することができる。 In the hydrogen purification method of this embodiment, for one cycle by the PSA method carried out in each of the adsorption towers 10A, 10B, 10C, after the adsorption process, the residual gas in the tower is transferred to another adsorption tower after the desorption process. Introduce and perform the cleaning process. The gas in the adsorption tower after completion of the adsorption process is a gas having a low impurity concentration (residual concentrated hydrogen gas), and the adsorption tower after the desorption process can be efficiently washed using the gas. Further, since the product gas is not used for cleaning, it is possible to suppress a decrease in the hydrogen recovery rate.
　各吸着塔１０Ａ，１０Ｂ，１０Ｃに充填される吸着剤については、原料ガスの流れ方向において最も上流側に、第１吸着剤１３１としてのシリカゲル系吸着剤が充填されている。シリカゲル系吸着剤は、０．１～１．０ＭＰａＧ（＝１００～１０００ｋＰａＧ）の高圧での揮発性炭化水素の吸着能に優れ、大気圧以上である０～５０ｋＰａＧでの最低圧力（脱着工程）でも揮発性炭化水素が脱着し再生可能である。この第１吸着剤１３１が吸着剤充填容量全体の１５～６５ｖｏｌ％使用されている。また、第１吸着剤１３１の下流側には、第２吸着剤１３２としての活性炭系吸着剤が充填されている。活性炭系吸着剤は、０．１～１．０ＭＰａＧの高圧での硫化水素の吸着能に優れ、大気圧以上である０～５０ｋＰａＧへの減圧状態でも硫化水素が脱着し再生可能である。この第２吸着剤１３２が吸着剤充填容量全体の１０～５０ｖｏｌ％使用されている。さらに、第２吸着剤１３２のさらに下流側には、第３吸着剤１３３としてのゼオライト系吸着剤が充填されている。ゼオライト系吸着剤は、０．１～１．０ＭＰａＧの高圧での炭化水素ガスの吸着能に優れ、大気圧以上である０～５０ｋＰａＧへの減圧状態でも炭化水素ガスが脱着し再生可能である。この第３吸着剤１３３が吸着剤充填容量全体の２５～７５ｖｏｌ％使用されている。以上のような構成によれば、不純物（揮発性炭化水素、炭化水素ガス、硫化水素）を効率よく吸着除去することができ、また真空設備が不要であるので、コスト削減を図ることができる。また、第１吸着剤１３１として親水性シリカゲルを用いれば、前処理を行うことなく揮発性炭化水素を適切に吸着除去することができ、コスト削減に資する。 The adsorbent filled in each of the adsorption towers 10A, 10B, and 10C is filled with a silica gel-based adsorbent as the first adsorbent 131 on the most upstream side in the flow direction of the raw material gas. Silica gel-based adsorbents are excellent in adsorbing volatile hydrocarbons at high pressures of 0.1 to 1.0 MPaG (= 100 to 1000 kPaG), and even at the lowest pressure (desorption process) at 0 to 50 kPaG, which is higher than atmospheric pressure. Volatile hydrocarbons can be desorbed and regenerated. The first adsorbent 131 is used in an amount of 15 to 65 vol% of the entire adsorbent filling capacity. Further, on the downstream side of the first adsorbent 131, an activated carbon adsorbent as the second adsorbent 132 is filled. The activated carbon-based adsorbent is excellent in the ability to adsorb hydrogen sulfide at a high pressure of 0.1 to 1.0 MPaG, and the hydrogen sulfide can be desorbed and regenerated even under a reduced pressure of 0 to 50 kPaG which is equal to or higher than atmospheric pressure. The second adsorbent 132 is used in an amount of 10 to 50 vol% of the entire adsorbent filling capacity. Furthermore, a zeolite-based adsorbent as the third adsorbent 133 is filled further downstream of the second adsorbent 132. The zeolite-based adsorbent is excellent in the adsorption ability of hydrocarbon gas at a high pressure of 0.1 to 1.0 MPaG, and the hydrocarbon gas can be desorbed and regenerated even under a reduced pressure of 0 to 50 kPaG which is equal to or higher than atmospheric pressure. This third adsorbent 133 is used in an amount of 25 to 75 vol% of the entire adsorbent filling capacity. According to the above configuration, impurities (volatile hydrocarbons, hydrocarbon gas, hydrogen sulfide) can be efficiently adsorbed and removed, and since no vacuum equipment is required, cost reduction can be achieved. Further, if hydrophilic silica gel is used as the first adsorbent 131, volatile hydrocarbons can be appropriately adsorbed and removed without pretreatment, which contributes to cost reduction.
　なお、第１吸着剤１３１の充填比率が１５ｖｏｌ％未満であると、揮発性炭化水素が十分に除去できなくなるおそれがある。その一方、第１吸着剤１３１の充填比率が７５ｖｏｌ％を超えると、第３吸着剤１３３において残留する洗浄ガスの割合が低下し、洗浄ガス量が減少して洗浄工程における洗浄が不十分となるおそれがある。また、第２吸着剤１３２の充填比率が１０ｖｏｌ％未満であると、硫化水素が十分に除去できなくなるおそれがある。その一方、第２吸着剤１３２の充填比率が５０ｖｏｌ％を超えると、第３吸着剤１３３において残留する洗浄ガスの割合が低下し、洗浄ガス量が減少して洗浄工程における洗浄が不十分となるおそれがある。 Note that if the filling ratio of the first adsorbent 131 is less than 15 vol%, volatile hydrocarbons may not be sufficiently removed. On the other hand, when the filling ratio of the first adsorbent 131 exceeds 75 vol%, the ratio of the cleaning gas remaining in the third adsorbent 133 decreases, the amount of cleaning gas decreases, and the cleaning in the cleaning process becomes insufficient. There is a fear. Further, if the filling ratio of the second adsorbent 132 is less than 10 vol%, hydrogen sulfide may not be sufficiently removed. On the other hand, when the filling ratio of the second adsorbent 132 exceeds 50 vol%, the ratio of the cleaning gas remaining in the third adsorbent 133 decreases, the amount of cleaning gas decreases, and the cleaning in the cleaning process becomes insufficient. There is a fear.
　第１吸着剤１３１の後段（下流側）に積層された、第２吸着剤１３２（活性炭系吸着剤）および第３吸着剤１３３（ゼオライト系吸着剤）においては、揮発性炭化水素を吸着させない。また、第２吸着剤１３２の後段に積層された、第３吸着剤１３３（ゼオライト系吸着剤）においては、揮発性炭化水素および硫化水素を吸着させない。即ち、吸着工程は第１吸着剤１３１および第２吸着剤１３２がそれぞれ揮発性炭化水素および硫化水素で飽和する前に終了しており、第３吸着剤１３３は、揮発性炭化水素および硫化水素を実質的に吸着しない。その一方、第３吸着剤１３３は、第１吸着剤１３１および第２吸着剤１３２と比べると、より多くの水素を吸着する。これにより、吸着工程が終了して減圧工程にある吸着塔から排出されて、脱着工程が終了して洗浄工程にある他の吸着塔の洗浄に使用される洗浄ガスは、減圧工程開始時に塔内に残留する濃縮水素ガス（主にガス通過口１２から近い、第３吸着剤１３３の充填領域にあるガス）の他に、第３吸着剤１３３から脱着する水素が加わる。その結果、水素含有量が高められた洗浄ガスを用いて脱着工程終了後の他の吸着塔を効果的に洗浄することができる。 In the second adsorbent 132 (activated carbon-based adsorbent) and the third adsorbent 133 (zeolite-based adsorbent) stacked on the subsequent stage (downstream side) of the first adsorbent 131, volatile hydrocarbons are not adsorbed. In addition, the third adsorbent 133 (zeolite adsorbent) stacked after the second adsorbent 132 does not adsorb volatile hydrocarbons and hydrogen sulfide. That is, the adsorption process is completed before the first adsorbent 131 and the second adsorbent 132 are saturated with volatile hydrocarbons and hydrogen sulfide, respectively, and the third adsorbent 133 removes volatile hydrocarbons and hydrogen sulfide. Does not substantially adsorb. On the other hand, the third adsorbent 133 adsorbs more hydrogen than the first adsorbent 131 and the second adsorbent 132. As a result, the cleaning gas exhausted from the adsorption tower in the depressurization process after completion of the adsorption process and used for cleaning other adsorption towers in the desorption process after completion of the desorption process is Hydrogen desorbed from the third adsorbent 133 is added to the concentrated hydrogen gas remaining in the gas (mainly the gas in the filling region of the third adsorbent 133 close to the gas passage port 12). As a result, the other adsorption tower after the completion of the desorption process can be effectively cleaned using the cleaning gas having an increased hydrogen content.
　以上、本発明の具体的な実施形態を説明したが、本発明はこれに限定されるものではなく、発明の思想から逸脱しない範囲内で種々の変更が可能である。例えば、本発明に係る水素またはヘリウムの精製方法を実施する装置におけるガス流路をなすライン（配管）の構成については、上記実施形態とは異なる構成を採用してもよい。吸着塔の数については上記実施形態で示した３塔式だけに限定されるものではなく、４塔以上の場合でも同様の効果が期待できる。 Although specific embodiments of the present invention have been described above, the present invention is not limited to these embodiments, and various modifications can be made without departing from the spirit of the invention. For example, a configuration different from the above-described embodiment may be adopted for the configuration of the line (pipe) forming the gas flow path in the apparatus for carrying out the method for purifying hydrogen or helium according to the present invention. The number of adsorption towers is not limited to the three-column type shown in the above embodiment, and the same effect can be expected even when there are four or more towers.
　また、上記実施形態では、水素を精製する場合について説明したが、本発明に係る精製方法で用いる吸着剤（第１吸着剤、第２吸着剤、および第３吸着剤）に対するヘリウムの吸着能が水素と略同じである。したがって、主成分であるヘリウムと不純物としての炭化水素ガスおよび／または揮発性炭化水素（あるいは炭化水素ガスおよび／または揮発性炭化水素＋硫化水素）を含む原料ガスからヘリウムを濃縮精製する場合においても、上記実施形態と同様の作用効果を奏する。なお、不純物である硫化水素の原料ガス中の濃度は他の不純物成分と比べて無視できる程度に低い場合には、硫化水素の除去は必要なくなる。本発明はそのような場合についても適用可能である。 Moreover, although the said embodiment demonstrated the case where hydrogen was refine | purified, helium adsorption ability with respect to the adsorbent (1st adsorbent, 2nd adsorbent, and 3rd adsorbent) used with the refinement | purification method which concerns on this invention is demonstrated. It is almost the same as hydrogen. Therefore, even when helium is concentrated and purified from a raw material gas containing helium as a main component and hydrocarbon gas and / or volatile hydrocarbon (or hydrocarbon gas and / or volatile hydrocarbon + hydrogen sulfide) as impurities. The same effects as those of the above embodiment are achieved. If the concentration of hydrogen sulfide, which is an impurity, in the raw material gas is negligibly low compared to other impurity components, it is not necessary to remove hydrogen sulfide. The present invention is also applicable to such a case.
　次に、本発明の有用性を実施例および比較例により説明する。 Next, the usefulness of the present invention will be described with reference to examples and comparative examples.
　〔実施例１〕
　本実施例では、図１に示した精製装置Ｘを用いて、図２を参照して説明した各ステップからなる圧力変動吸着法（ＰＳＡ法）を利用した精製方法により、以下に示す条件下で、原料ガスから製品ガスとしての濃縮水素ガスを取得した。 [Example 1]
In this example, the purification apparatus X shown in FIG. 1 was used and the purification method using the pressure fluctuation adsorption method (PSA method) composed of the steps described with reference to FIG. The concentrated hydrogen gas was obtained from the source gas as the product gas.
　吸着塔１０Ａ，１０Ｂ，１０Ｃとしては、内径が３５ｍｍの円筒状のものを用い、吸着剤充填容量が約１Ｌ（リットル）とされた。各吸着塔１０Ａ，１０Ｂ，１０Ｃには、ガス通過口１１からガス通過口１２に向けて、第１吸着剤１３１としてのシリカゲルＢ型（富士シリシア化学社製フジシリカゲルＢ型）、第２吸着剤１３２としての活性炭（キャタラー社製ＰＧＡＲ）、および第３吸着剤１３３としてのＣａＡ型ゼオライト（ユニオン昭和社製５ＡＨＰ）を、積層充填した。これら吸着剤の充填比率（体積割合）は、第１吸着剤１３１が３０ｖｏｌ％、第２吸着剤１３２が１０ｖｏｌ％、第３吸着剤１３３が６０ｖｏｌ％とした。原料ガスについては、不純物として、メタンを１２００ｖｏｌｐｐｍ、トルエンを８５００ｖｏｌｐｐｍ、硫化水素を０．１ｖｏｌｐｐｍ含有する粗水素ガスが用いられ、当該原料ガスを５．２ＮＬ／ｍｉｎ（Ｎは標準状態を表す）の流量で供給した。ＰＳＡ法による操作条件は、吸着塔等の温度が４０℃、吸着圧力が０．８ＭＰａＧ、脱着圧力が２０ｋＰａＧ、洗浄圧力差が３００ｋＰａ、サイクルタイム（ステップ１～９より構成される１サイクルの時間）が６７５秒とした。また、得られた濃縮水素ガス（製品ガス）における不純物濃度を水素炎イオン検出器（ＦＩＤ）および炎光光度検出器（ＦＰＤ）で測定したところ、製品ガス中のトルエン濃度は定量下限以下（０．１ｖｏｌｐｐｍ以下）、メタン濃度は０．０４ｖｏｌｐｐｍ、硫化水素濃度は定量下限以下（０．１ｖｏｌｐｐｂ以下）であり、水素ガス回収率は７５％であった。本実施例の結果を表１に示した。 As the adsorption towers 10A, 10B, and 10C, cylindrical ones having an inner diameter of 35 mm were used, and the adsorbent filling capacity was about 1 L (liter). In each of the adsorption towers 10 </ b> A, 10 </ b> B, 10 </ b> C, from the gas passage port 11 toward the gas passage port 12, silica gel B type (Fuji Silica Silica B type manufactured by Fuji Silysia Chemical Co.) Activated carbon as 132 (PGAR manufactured by Caterer) and CaA-type zeolite (5AHP manufactured by Union Showa) as the third adsorbent 133 were stacked and filled. The filling ratio (volume ratio) of these adsorbents was 30 vol% for the first adsorbent 131, 10 vol% for the second adsorbent 132, and 60 vol% for the third adsorbent 133. For the raw material gas, crude hydrogen gas containing 1200 volppm of methane, 8500 volppm of toluene, and 0.1 volppm of hydrogen sulfide is used as impurities, and the raw material gas has a flow rate of 5.2 NL / min (N represents a standard state). Supplied with. The operating conditions by the PSA method are as follows: adsorption tower temperature is 40 ° C., adsorption pressure is 0.8 MPaG, desorption pressure is 20 kPaG, cleaning pressure difference is 300 kPa, cycle time (one cycle time composed of steps 1 to 9) Was 675 seconds. Further, when the impurity concentration in the obtained concentrated hydrogen gas (product gas) was measured with a flame ion detector (FID) and a flame photometric detector (FPD), the toluene concentration in the product gas was below the lower limit of quantification (0 0.1 volppm or less), the methane concentration was 0.04 volppm, the hydrogen sulfide concentration was below the lower limit of quantification (0.1 volppb or less), and the hydrogen gas recovery rate was 75%. The results of this example are shown in Table 1.
　〔実施例２〕
　吸着剤の充填比率を、第１吸着剤１３１が２０ｖｏｌ％、第２吸着剤１３２が４０ｖｏｌ％、第３吸着剤１３３が４０ｖｏｌ％とした以外は、実施例１と同様にして、原料ガスから水素の精製を行った。また、得られた濃縮水素ガス（製品ガス）における不純物濃度を水素炎イオン検出器（ＦＩＤ）および炎光光度検出器（ＦＰＤ）で測定したところ、製品ガス中のトルエン濃度は定量下限以下（０．１ｖｏｌｐｐｍ以下）、メタン濃度は０．２１ｖｏｌｐｐｍ、硫化水素濃度は定量下限以下（０．１ｖｏｌｐｐｂ以下）であり、水素ガス回収率は７０％であった。本実施例の結果を表１に示した。 [Example 2]
In the same manner as in Example 1, except that the filling ratio of the adsorbent was 20 vol% for the first adsorbent 131, 40 vol% for the second adsorbent 132, and 40 vol% for the third adsorbent 133, Was purified. Further, when the impurity concentration in the obtained concentrated hydrogen gas (product gas) was measured with a flame ion detector (FID) and a flame photometric detector (FPD), the toluene concentration in the product gas was below the lower limit of quantification (0 0.1 volppm or less), the methane concentration was 0.21 volppm, the hydrogen sulfide concentration was below the lower limit of quantification (0.1 volppb or less), and the hydrogen gas recovery rate was 70%. The results of this example are shown in Table 1.
　〔実施例３〕
　吸着剤の充填比率を、第１吸着剤１３１が４０ｖｏｌ％、第２吸着剤１３２が３０ｖｏｌ％、第３吸着剤１３３が３０ｖｏｌ％とした以外は、実施例１と同様にして、原料ガスから水素の精製を行った。また、得られた濃縮水素ガス（製品ガス）における不純物濃度を水素炎イオン検出器（ＦＩＤ）および炎光光度検出器（ＦＰＤ）で測定したところ、製品ガス中のトルエン濃度は定量下限以下（０．１ｖｏｌｐｐｍ以下）、メタン濃度は０．５ｖｏｌｐｐｍ、硫化水素濃度は定量下限以下（０．１ｖｏｌｐｐｂ以下）であり、水素ガス回収率は８０％であった。本実施例の結果を表１に示した。 Example 3
In the same manner as in Example 1, except that the filling ratio of the adsorbent was 40 vol% for the first adsorbent 131, 30 vol% for the second adsorbent 132, and 30 vol% for the third adsorbent 133, Was purified. Further, when the impurity concentration in the obtained concentrated hydrogen gas (product gas) was measured with a flame ion detector (FID) and a flame photometric detector (FPD), the toluene concentration in the product gas was below the lower limit of quantification (0 0.1 volppm or less), the methane concentration was 0.5 volppm, the hydrogen sulfide concentration was below the lower limit of quantification (0.1 volppb or less), and the hydrogen gas recovery rate was 80%. The results of this example are shown in Table 1.
　〔実施例４〕
　吸着剤の充填比率を、第１吸着剤１３１が６０ｖｏｌ％、第２吸着剤１３２が１０ｖｏｌ％、第３吸着剤１３３が３０ｖｏｌ％とした以外は、実施例１と同様にして、原料ガスから水素の精製を行った。また、得られた濃縮水素ガス（製品ガス）における不純物濃度を水素炎イオン検出器（ＦＩＤ）および炎光光度検出器（ＦＰＤ）で測定したところ、製品ガス中のトルエン濃度は０．６ｖｏｌｐｐｍ、メタン濃度は０．９ｖｏｌｐｐｍ、硫化水素濃度は定量下限以下（０．１ｖｏｌｐｐｂ以下）であり、水素ガス回収率は８５％であった。本実施例の結果を表１に示した。 Example 4
In the same manner as in Example 1, except that the filling ratio of the adsorbent was 60 vol% for the first adsorbent 131, 10 vol% for the second adsorbent 132, and 30 vol% for the third adsorbent 133, Was purified. Moreover, when the impurity concentration in the obtained concentrated hydrogen gas (product gas) was measured with a flame ion detector (FID) and a flame photometric detector (FPD), the toluene concentration in the product gas was 0.6 volppm, methane The concentration was 0.9 volppm, the hydrogen sulfide concentration was below the lower limit of quantification (0.1 volppb or less), and the hydrogen gas recovery rate was 85%. The results of this example are shown in Table 1.
　〔比較例１〕
　吸着剤の充填比率（体積割合）を、第１吸着剤１３１が８０ｖｏｌ％、第２吸着剤１３２が１０ｖｏｌ％、第３吸着剤１３３が１０ｖｏｌ％とした以外は、実施例１と同様にして、原料ガスから水素の精製を行った。また、得られた濃縮水素ガス（製品ガス）における不純物濃度を水素炎イオン検出器（ＦＩＤ）および炎光光度検出器（ＦＰＤ）で測定したところ、製品ガス中のトルエン濃度は２０００ｖｏｌｐｐｍ、メタン濃度は２．２ｖｏｌｐｐｍ、硫化水素濃度は定量下限以下（０．１ｖｏｌｐｐｂ以下）であり、水素ガス回収率は９０％であった。本比較例の結果を表１に示した。 [Comparative Example 1]
The adsorbent filling ratio (volume ratio) was the same as in Example 1 except that the first adsorbent 131 was 80 vol%, the second adsorbent 132 was 10 vol%, and the third adsorbent 133 was 10 vol%. Hydrogen was purified from the source gas. Moreover, when the impurity concentration in the obtained concentrated hydrogen gas (product gas) was measured with a hydrogen flame ion detector (FID) and a flame photometric detector (FPD), the toluene concentration in the product gas was 2000 volppm, and the methane concentration was 2.2 volppm, the hydrogen sulfide concentration was below the lower limit of quantification (0.1 volppb or less), and the hydrogen gas recovery rate was 90%. The results of this comparative example are shown in Table 1.
　〔比較例２〕
　吸着剤の充填比率（体積割合）を、第１吸着剤１３１が１０ｖｏｌ％、第２吸着剤１３２が１０ｖｏｌ％、第３吸着剤１３３が８０ｖｏｌ％とした以外は、実施例１と同様にして、原料ガスから水素の精製を行った。また、得られた濃縮水素ガス（製品ガス）における不純物濃度を水素炎イオン検出器（ＦＩＤ）および炎光光度検出器（ＦＰＤ）で測定したところ、製品ガス中のトルエン濃度は３０００ｖｏｌｐｐｍ、メタン濃度は０．０１ｖｏｌｐｐｍ、硫化水素濃度は定量下限以下（０．１ｖｏｌｐｐｂ以下）であり、水素ガス回収率は７０％であった。本比較例の結果を表１に示した。 [Comparative Example 2]
The same as in Example 1 except that the adsorbent filling ratio (volume ratio) was 10 vol% for the first adsorbent 131, 10 vol% for the second adsorbent 132, and 80 vol% for the third adsorbent 133. Hydrogen was purified from the source gas. Moreover, when the impurity concentration in the obtained concentrated hydrogen gas (product gas) was measured with a hydrogen flame ion detector (FID) and a flame photometric detector (FPD), the toluene concentration in the product gas was 3000 volppm, and the methane concentration was The 0.01 volppm, hydrogen sulfide concentration was below the lower limit of quantification (0.1 volppb or less), and the hydrogen gas recovery rate was 70%. The results of this comparative example are shown in Table 1.
　〔比較例３〕
　吸着剤の充填比率を、第１吸着剤１３１が１０ｖｏｌ％、第２吸着剤１３２が６０ｖｏｌ％、第３吸着剤１３３が３０ｖｏｌ％とした以外は、実施例１と同様にして、原料ガスから水素の精製を行った。その結果を表１に示した。また、得られた濃縮水素ガス（製品ガス）における不純物濃度を水素炎イオン検出器（ＦＩＤ）および炎光光度検出器（ＦＰＤ）で測定したところ、製品ガス中のトルエン濃度は１０００ｖｏｌｐｐｍ、メタン濃度は１．５ｖｏｌｐｐｍ、硫化水素濃度は定量下限以下（０．１ｖｏｌｐｐｂ以下）であり、水素ガス回収率は６５％であった。本比較例の結果を表１に示した。 [Comparative Example 3]
In the same manner as in Example 1, except that the filling ratio of the adsorbent was 10 vol% for the first adsorbent 131, 60 vol% for the second adsorbent 132, and 30 vol% for the third adsorbent 133, hydrogen was supplied from the source gas. Was purified. The results are shown in Table 1. Moreover, when the impurity concentration in the obtained concentrated hydrogen gas (product gas) was measured with a hydrogen flame ion detector (FID) and a flame photometric detector (FPD), the toluene concentration in the product gas was 1000 volppm, and the methane concentration was The 1.5 volppm hydrogen sulfide concentration was below the lower limit of quantification (0.1 volppb or less), and the hydrogen gas recovery rate was 65%. The results of this comparative example are shown in Table 1.
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
　表１から明らかなように、上記各実施例によれば、水素ガスを高純度に精製できることが確認される。 As is apparent from Table 1, according to each of the above examples, it is confirmed that hydrogen gas can be purified with high purity.
Ｘ　　　　精製装置
１０Ａ，１０Ｂ，１０Ｃ　　吸着塔
１１　　　ガス通過口（第１ガス通過口）
１２　　　ガス通過口（第２ガス通過口）
１３１　　第１吸着剤
１３２　　第２吸着剤
１３３　　第３吸着剤
２１　　　原料ガス供給源
２２　　　製品貯留タンク
２３　　　オフガスタンク
２４　　　冷却器（気液分離手段）
２５　　　気液分離器（気液分離手段）
３１　　　ライン（第１ライン）
３２　　　ライン（第２ライン）
３３　　　ライン（第３ライン）
３４　　　ライン（第４ライン）
３５　　　ライン（第５ライン）
３１’，３２’，３３’，３４’，３５' 主幹路
３１Ａ～３１Ｃ，３２Ａ～３２Ｃ，３３Ａ～３３Ｃ，３４Ａ～３４Ｃ，３５Ａ～３５Ｃ　
　　分枝路
３１ａ～３１ｃ，３２ａ～３２ｃ，３３ａ～３３ｃ，３４ａ～３４ｃ，３５ａ～３５ｃ，３４１，３５１　　自動弁
３２１，３３１　　圧力調節弁
３４２，３５２　　流量調整弁 X purification apparatus 10A, 10B, 10C Adsorption tower 11 Gas passage (first gas passage)
12 Gas passage (second gas passage)
131 First adsorbent 132 Second adsorbent 133 Third adsorbent 21 Source gas supply source 22 Product storage tank 23 Off-gas tank 24 Cooler (gas-liquid separation means)
25 Gas-liquid separator (gas-liquid separation means)
31 lines (1st line)
32 lines (second line)
33 lines (3rd line)
34 lines (4th line)
35 lines (5th line)
31 ', 32', 33 ', 34', 35 'Main roads 31A to 31C, 32A to 32C, 33A to 33C, 34A to 34C, 35A to 35C
Branch passages 31a to 31c, 32a to 32c, 33a to 33c, 34a to 34c, 35a to 35c, 341 and 351 Automatic valves 321 and 331 Pressure regulating valves 342 and 352 Flow regulating valves

Claims (13)

  1. 　吸着剤が充填された３塔以上の吸着塔を用いて行う圧力変動吸着法のサイクルを各吸着塔について繰り返すことにより、不純物として炭化水素ガスまたは揮発性炭化水素の少なくとも一方を含み、且つ主成分として水素またはヘリウムを含む原料ガスから水素またはヘリウムを精製するための方法であって、上記サイクルは、
    　上記吸着塔が所定の高圧である状態にて、上記吸着塔に上記原料ガスを導入して当該原料ガス中の上記炭化水素ガスまたは揮発性炭化水素の少なくとも一方を上記吸着剤に吸着させ、当該吸着塔から水素またはヘリウムの濃度が高い製品ガスを排出する吸着工程と、
    　上記吸着工程を終えた上記吸着塔から塔内に残留するガスを排出して塔内の圧力を低下させる減圧工程と、
    　上記減圧工程を終えた上記吸着塔における上記吸着剤から上記炭化水素ガスまたは揮発性炭化水素の少なくとも一方を脱着させ、塔内ガスを排出する脱着工程と、
    　上記減圧工程にある他の吸着塔から排出されたガスを上記脱着工程を終えた上記吸着塔に導入して塔内に残留するガスを排出する洗浄工程と、を含んでおり、
    　上記各吸着塔は、上記吸着塔における上記原料ガスの流れ方向において上流側から下流側に向けて順に第１領域、第２領域および第３領域に区分されており、上記第１領域には、上記吸着剤の充填容量全体に対し、充填比率が１５～６５ｖｏｌ％の範囲であるシリカゲル系の第１吸着剤が充填されており、上記第２領域には、充填比率が１０～５０ｖｏｌ％の範囲である活性炭系の第２吸着剤が充填されており、上記第３領域には、充填比率が２５～７５ｖｏｌ％の範囲であるゼオライト系の第３吸着剤が充填されている、水素またはヘリウムの精製方法。     By repeating the cycle of the pressure fluctuation adsorption method using three or more adsorption towers filled with an adsorbent for each adsorption tower, the main component contains at least one of hydrocarbon gas or volatile hydrocarbon, and the main component A method for purifying hydrogen or helium from a source gas containing hydrogen or helium as
    In a state where the adsorption tower is at a predetermined high pressure, the raw material gas is introduced into the adsorption tower to adsorb at least one of the hydrocarbon gas or volatile hydrocarbon in the raw material gas to the adsorbent, An adsorption process for discharging a product gas having a high hydrogen or helium concentration from the adsorption tower;
    A depressurization step for reducing the pressure in the tower by discharging the gas remaining in the tower from the adsorption tower after the adsorption step;
    A desorption step of desorbing at least one of the hydrocarbon gas or volatile hydrocarbon from the adsorbent in the adsorption tower after the decompression step and discharging the gas in the column;
    A cleaning step of introducing the gas discharged from the other adsorption tower in the decompression step into the adsorption tower after the desorption step and discharging the gas remaining in the tower,
    Each of the adsorption towers is divided into a first area, a second area, and a third area in order from the upstream side to the downstream side in the flow direction of the raw material gas in the adsorption tower. In the first area, The silica gel-based first adsorbent having a filling ratio in the range of 15 to 65 vol% is filled with respect to the entire filling capacity of the adsorbent, and the filling ratio is in the range of 10 to 50 vol% in the second area. Activated carbon-based second adsorbent, and the third region is filled with a zeolite-based third adsorbent having a filling ratio in the range of 25 to 75 vol%. Purification method.
  2. 　上記原料ガスは、不純物として硫化水素をさらに含む、請求項１に記載の精製方法。 The purification method according to claim 1, wherein the source gas further contains hydrogen sulfide as an impurity.
  3. 　上記第１吸着剤は、親水性シリカゲルを含む、請求項１に記載の精製方法。 The purification method according to claim 1, wherein the first adsorbent contains hydrophilic silica gel.
  4. 　上記第２吸着剤は、椰子殻由来の活性炭または石炭由来の活性炭を含む、請求項１に記載の精製方法。 The purification method according to claim 1, wherein the second adsorbent includes activated carbon derived from coconut shell or activated carbon derived from coal.
  5. 　上記第３吸着剤は、ＣａＡ型ゼオライトを含む、請求項１に記載の精製方法。 The purification method according to claim 1, wherein the third adsorbent contains CaA-type zeolite.
  6. 　上記洗浄工程と上記吸着工程との間に上記吸着塔の圧力を所定の吸着圧力まで高めるための昇圧工程をさらに含む、請求項１に記載の精製方法。 The purification method according to claim 1, further comprising a pressure increasing step for increasing the pressure of the adsorption tower to a predetermined adsorption pressure between the washing step and the adsorption step.
  7. 　上記減圧工程は、上記吸着塔から排出された残留ガスを上記洗浄工程にある他の吸着塔に洗浄ガスとして導入する第１減圧ステップと、当該第１減圧ステップに引き続いて、上記吸着塔から排出された残留ガスを上記昇圧工程にある他の吸着塔に導入する第２減圧ステップと、を含む、請求項６に記載の精製方法。 The depressurization step includes a first depressurization step for introducing the residual gas discharged from the adsorption tower as a cleaning gas into another adsorption tower in the cleaning step, and a discharge from the adsorption tower following the first depressurization step. And a second depressurizing step for introducing the residual gas into the other adsorption tower in the pressure increasing step.
  8. 　上記昇圧工程は、上記第１減圧ステップにある他の吸着塔から排出された残留ガスを上記吸着塔に導入する第１昇圧ステップと、当該第１昇圧ステップに引き続いて、上記吸着工程にある他の吸着塔からの製品ガスの一部を上記吸着塔に導入する第２昇圧ステップと、を含む、請求項７に記載の精製方法。 The pressure increasing step includes a first pressure increasing step for introducing residual gas discharged from another adsorption tower in the first pressure reducing step into the adsorption tower, and a step in the adsorption step subsequent to the first pressure increasing step. And a second pressure-increasing step for introducing a part of the product gas from the adsorption tower into the adsorption tower.
  9. 　不純物として炭化水素ガスまたは揮発性炭化水素の少なくとも一方を含み、且つ主成分として水素またはヘリウムを含む原料ガスから水素またはヘリウムを精製するための装置であって、
    　各々が第１ガス通過口および第２ガス通過口を有し、当該第１および第２ガス通過口の間において吸着剤が充填された３塔以上の吸着塔と、
    　製品ガスを貯留するための貯留タンクと、
    　上記吸着塔の上記第１ガス通過口から排出されるガスを気相成分と液相成分とに分離する気液分離手段と、
    　原料ガス供給源に接続された主幹路、および、上記吸着塔ごとに設けられて当該吸着塔の上記第１ガス通過口側に接続され且つ開閉弁が各々に設けられた複数の分枝路、を有する第１ラインと、
    　上記気液分離手段が設けられた主幹路、および、上記吸着塔ごとに設けられて当該吸着塔の上記第１ガス通過口側に接続され且つ開閉弁が各々に設けられた複数の分枝路、を有する第２ラインと、
    　上記貯留タンクが設けられた主幹路、および、上記吸着塔ごとに設けられて当該吸着塔の上記第２ガス通過口側に接続され且つ開閉弁が各々に設けられた複数の分枝路、を有する第３ラインと、
    　上記第３ラインにおける上記主幹路に接続された主幹路、および、上記吸着塔ごとに設けられて当該吸着塔の上記第２ガス通過口側に接続され且つ開閉弁が各々に設けられた複数の分枝路、を有する第４ラインと、
    　上記第４ラインにおける上記主幹路に接続された主幹路、および、上記吸着塔ごとに設けられて当該吸着塔の上記第２ガス通過口側に接続され且つ開閉弁が各々に設けられた複数の分枝路、を有する第５ラインと、を備え、
    　上記各吸着塔は、上記吸着塔における上記第１ガス通過口から上記第２ガス通過口に向けて順に第１領域、第２領域および第３領域に区分されており、上記第１領域には、上記吸着剤の充填容量全体に対し、充填比率が１５～６５ｖｏｌ％の範囲であるシリカゲル系の第１吸着剤が充填されており、上記第２領域には、充填比率が１０～５０ｖｏｌ％の範囲である活性炭系の第２吸着剤が充填されており、上記第３領域には、充填比率が２５～７５ｖｏｌ％の範囲であるゼオライト系の第３吸着剤が充填されている、水素またはヘリウムの精製装置。     An apparatus for purifying hydrogen or helium from a source gas containing at least one of hydrocarbon gas or volatile hydrocarbon as an impurity and containing hydrogen or helium as a main component,
    Three or more adsorption towers each having a first gas passage opening and a second gas passage opening and filled with an adsorbent between the first and second gas passage openings;
    A storage tank for storing product gas;
    Gas-liquid separation means for separating the gas discharged from the first gas passage port of the adsorption tower into a gas phase component and a liquid phase component;
    A main path connected to the source gas supply source, and a plurality of branch paths provided for each of the adsorption towers and connected to the first gas passage side of the adsorption tower and provided with on-off valves, A first line having:
    A main passage provided with the gas-liquid separation means, and a plurality of branch passages provided for each of the adsorption towers and connected to the first gas passage port side of the adsorption tower and provided with on-off valves, respectively. A second line having
    A main passage provided with the storage tank, and a plurality of branch passages provided for each adsorption tower and connected to the second gas passage opening side of the adsorption tower and provided with on-off valves, respectively. Having a third line;
    A plurality of main roads connected to the main road in the third line, and a plurality of open / close valves provided for each of the adsorption towers and connected to the second gas passage opening side of the adsorption tower. A fourth line having a branch path;
    A plurality of main roads connected to the main road in the fourth line, and a plurality of open / close valves provided for each of the adsorption towers and connected to the second gas passage port side of the adsorption tower. A fifth line having a branch path,
    Each adsorption tower is divided into a first region, a second region, and a third region in order from the first gas passage port to the second gas passage port in the adsorption tower. The silica gel-based first adsorbent having a filling ratio in the range of 15 to 65 vol% is filled with respect to the entire filling capacity of the adsorbent, and the filling ratio is 10 to 50 vol% in the second region. Hydrogen or helium filled with activated carbon-based second adsorbent in the range, and the third region filled with zeolite-based third adsorbent with a filling ratio in the range of 25 to 75 vol% Purification equipment.
  10. 　上記原料ガスは、不純物として硫化水素をさらに含む、請求項９に記載の精製装置。 The purification apparatus according to claim 9, wherein the source gas further contains hydrogen sulfide as an impurity.
  11. 　上記第１吸着剤は、親水性シリカゲルを含む、請求項９に記載の精製装置。 The purification apparatus according to claim 9, wherein the first adsorbent includes hydrophilic silica gel.
  12. 　上記第２吸着剤は、椰子殻由来の活性炭または石炭由来の活性炭を含む、請求項９に記載の精製装置。 The purification apparatus according to claim 9, wherein the second adsorbent includes activated carbon derived from coconut shell or activated carbon derived from coal.
  13. 　上記第３吸着剤は、ＣａＡ型ゼオライトを含む、請求項９に記載の精製装置。 The purification apparatus according to claim 9, wherein the third adsorbent includes CaA-type zeolite.
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