WO2014181718A1 - Method for producing hydrogen - Google Patents

Method for producing hydrogen Download PDF

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Publication number
WO2014181718A1
WO2014181718A1 PCT/JP2014/061752 JP2014061752W WO2014181718A1 WO 2014181718 A1 WO2014181718 A1 WO 2014181718A1 JP 2014061752 W JP2014061752 W JP 2014061752W WO 2014181718 A1 WO2014181718 A1 WO 2014181718A1
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Prior art keywords
gas
hydrogen
catalyst
material gas
raw material
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PCT/JP2014/061752
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French (fr)
Japanese (ja)
Inventor
貴裕 土屋
光利 中谷
山本　守彦
康一 志摩
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住友精化株式会社
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Priority to JP2015515848A priority Critical patent/JPWO2014181718A1/en
Priority to KR1020157027509A priority patent/KR20160005015A/en
Publication of WO2014181718A1 publication Critical patent/WO2014181718A1/en

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    • 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
    • C01B3/02—Production of hydrogen or of gaseous mixtures containing a substantial proportion of hydrogen
    • C01B3/32—Production of hydrogen or of gaseous mixtures containing a substantial proportion of hydrogen by reaction of gaseous or liquid organic compounds with gasifying agents, e.g. water, carbon dioxide, air
    • C01B3/323—Catalytic reaction of gaseous or liquid organic compounds other than hydrocarbons with gasifying agents
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B2203/00—Integrated processes for the production of hydrogen or synthesis gas
    • C01B2203/02—Processes for making hydrogen or synthesis gas
    • C01B2203/025—Processes for making hydrogen or synthesis gas containing a partial oxidation step
    • C01B2203/0261—Processes for making hydrogen or synthesis gas containing a partial oxidation step containing a catalytic partial oxidation step [CPO]
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B2203/00—Integrated processes for the production of hydrogen or synthesis gas
    • C01B2203/02—Processes for making hydrogen or synthesis gas
    • C01B2203/0266—Processes for making hydrogen or synthesis gas containing a decomposition step
    • C01B2203/0277—Processes for making hydrogen or synthesis gas containing a decomposition step containing a catalytic decomposition step
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B2203/00—Integrated processes for the production of hydrogen or synthesis gas
    • C01B2203/10—Catalysts for performing the hydrogen forming reactions
    • C01B2203/1041—Composition of the catalyst
    • C01B2203/1076—Copper or zinc-based catalysts
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B2203/00—Integrated processes for the production of hydrogen or synthesis gas
    • C01B2203/10—Catalysts for performing the hydrogen forming reactions
    • C01B2203/1041—Composition of the catalyst
    • C01B2203/1082—Composition of support materials
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B2203/00—Integrated processes for the production of hydrogen or synthesis gas
    • C01B2203/16—Controlling the process
    • C01B2203/1614—Controlling the temperature
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P20/00—Technologies relating to chemical industry
    • Y02P20/50—Improvements relating to the production of bulk chemicals
    • Y02P20/52—Improvements relating to the production of bulk chemicals using catalysts, e.g. selective catalysts

Definitions

  • the present invention relates to a method for producing hydrogen. More specifically, the present invention relates to a method for producing hydrogen in which hydrogen is produced by reacting methanol with water and oxygen in the presence of a catalyst.
  • Methanol is an energy source that can be easily transported and stored, and is used as a raw material for generating hydrogen gas on-site.
  • a steam reforming method and a partial oxidation-steam reforming reaction method are generally known.
  • the steam reforming method is a method for producing hydrogen gas by bringing methanol vapor into contact with steam in the presence of a catalyst. Since this steam reforming reaction involves a relatively large endotherm, there is a drawback that the heat supply system such as a heat exchanger has a heavy load and takes a long time to start.
  • the partial oxidation-steam reforming reaction method is a method for producing hydrogen gas by bringing methanol vapor into contact with steam and oxygen in the presence of a catalyst.
  • this partial oxidation-steam reforming reaction method the heat generated when methanol is partially oxidized (partial oxidation reaction) to form carbon dioxide and hydrogen is converted into carbon dioxide by steam reforming in which methanol vapor and steam are brought into contact. Therefore, there is an advantage that the load of a heat supply system such as a heat exchanger can be reduced.
  • the partial oxidation reaction which is an exothermic reaction
  • the steam reforming reaction which is an endothermic reaction
  • Patent Document 1 uses a catalyst in which copper oxide is supported on aluminum oxide in a method for producing hydrogen by a partial oxidation-steam reforming reaction method, and contains oxygen as a raw material for a partial oxidation reaction that generates heat.
  • a method for temporarily stopping the supply of oxygen-containing gas to the reactor is disclosed.
  • Patent Document 2 discloses a raw material gas at a portion upstream of the flow direction of a raw material gas in a reactor in which a partial oxidation reaction accompanied by heat generation mainly proceeds in a method for producing hydrogen by a partial oxidation-steam reforming reaction method. A method for increasing the flow rate of the liquid is disclosed.
  • the temperature distribution of a reactor having a metal honeycomb structure can be controlled to 250 to 300 ° C. by increasing the flow rate of the source gas in the upstream portion of the reactor in the flow direction of the source gas.
  • this temperature is only an external temperature of a metal honeycomb made of a metal having high thermal conductivity.
  • the partial oxidation reaction accompanied by heat generation proceeds, on the upstream side in the flow direction of the raw material gas in the reactor. It is reasonable to think that the surface temperature of the catalyst present in the portion is higher than 300 ° C., which is higher than the temperature of the metal honeycomb having high thermal conductivity.
  • Patent Documents 1 and 2 have a short catalyst life, and hydrogen cannot be produced stably over a long period of time.
  • An object of the present invention is to increase the catalyst life and stably produce hydrogen over a long period of time in a hydrogen production method in which hydrogen is produced by a partial oxidation reaction and decomposition reaction of methanol. It is to provide a manufacturing method.
  • the present invention includes a temperature adjustment step of adjusting a raw material gas containing methanol, water, and oxygen to a predetermined reactionable temperature;
  • the raw material gas adjusted to the reaction possible temperature is caused to flow through a reactor filled with a particulate catalyst and brought into contact with the catalyst, thereby causing the partial oxidation reaction and decomposition reaction of methanol to proceed, thereby allowing hydrogen to flow.
  • a hydrogen production step to produce In the hydrogen generation step, by controlling the flow rate of the raw material gas flowing through the reactor, the maximum temperature of the catalyst surface in contact with the raw material gas during the partial oxidation reaction and decomposition reaction of methanol is 300 ° C. or less. It is the manufacturing method of hydrogen characterized by controlling to.
  • the flow rate of the raw material gas is adjusted so that the linear velocity of the raw material gas flowing through the reactor is 0.01 to 0.2 (Nm / s). Is preferably controlled.
  • the flow rate of the source gas in the hydrogen generation step, may be controlled so that the space velocity of the source gas flowing through the reactor is 200 to 1500 (/ h). preferable.
  • the catalyst is preferably a catalyst in which a copper compound is supported on aluminum oxide.
  • the method for producing hydrogen includes a temperature adjustment step and a hydrogen generation step.
  • the temperature adjustment step the raw material gas containing methanol, water and oxygen is adjusted to a predetermined reaction temperature.
  • the hydrogen generation step the raw material gas adjusted to the reaction possible temperature is caused to flow through the reactor filled with the particulate catalyst and brought into contact with the catalyst.
  • the source gas comes into contact with the catalyst in this manner, a partial oxidation reaction with methanol and oxygen and a decomposition reaction with methanol and water proceed.
  • the source gas is controlled by controlling the flow rate of the source gas flowing through the reactor. Is controlled to 300 ° C. or lower.
  • reaction rate difference between the partial oxidation reaction and the decomposition reaction and the maximum temperature on the catalyst surface.
  • the maximum temperature on the catalyst surface is set to 300 ° C. or lower. Can be controlled.
  • a partial oxidation reaction with a high reaction rate proceeds in the upstream portion of the raw material gas in the flow direction.
  • a decomposition reaction with a slow reaction rate proceeds in a portion downstream of the gas flow direction.
  • the reaction rate difference between the partial oxidation reaction and the decomposition reaction is reduced by controlling the flow rate of the raw material gas flowing through the reactor, and the raw material The partial oxidation reaction and the decomposition reaction proceed in substantially the same part in the reactor with respect to the gas flow direction.
  • the catalyst filled in the reactor is strongly affected only by the partial oxidation reaction with exotherm, and it is possible to suppress the occurrence of an excessively high temperature portion, and the maximum temperature of the catalyst surface can be reduced. It can be controlled to 300 ° C. or lower. Therefore, according to the method for producing hydrogen of the present invention, deterioration due to sintering can be suppressed and the catalyst life can be extended, and hydrogen can be produced stably over a long period of time.
  • the flow rate of the raw material gas is controlled so that the linear velocity of the raw material gas flowing through the reactor becomes 0.01 to 0.2 (Nm / s).
  • the reaction rate difference between the partial oxidation reaction and the decomposition reaction can be reliably reduced, and the flow rate of the raw material gas in the reactor can be reduced.
  • the partial oxidation reaction and the decomposition reaction can proceed in substantially the same part.
  • the maximum temperature of the catalyst surface can be more reliably controlled to 300 ° C. or lower, so that the catalyst life can be extended and hydrogen can be produced stably over a long period of time.
  • the linear velocity of the raw material gas flowing through the reactor is 0.01 to 0.2 (Nm / s) and the space velocity is 200 to 1500 (/ h)
  • the flow rate of the source gas is controlled so that By controlling the flow rate of the raw material gas flowing through the reactor in this way, the reaction rate difference between the partial oxidation reaction and the decomposition reaction can be reliably reduced, and the flow rate of the raw material gas in the reactor can be reduced.
  • the partial oxidation reaction and the decomposition reaction can proceed in substantially the same part.
  • the maximum temperature of the catalyst surface can be more reliably controlled to 300 ° C. or lower, so that the catalyst life can be extended and hydrogen can be produced stably over a long period of time.
  • a catalyst in which a copper compound is supported on aluminum oxide is used as the catalyst charged in the reactor.
  • This catalyst is excellent in that a decrease in catalytic activity is suppressed.
  • the aluminum oxide constituting this catalyst has a function of producing dimethyl ether from methanol at a high temperature exceeding 300 ° C. That is, when a catalyst in which a copper compound is supported on aluminum oxide is used, when the surface temperature of the catalyst exceeds 300 ° C., a reaction in which dimethyl ether is generated from methanol proceeds to generate hydrogen. The amount of methanol will decrease, leading to a decrease in hydrogen production yield.
  • the flow rate of the raw material gas flowing through the reactor is controlled, and the maximum temperature of the catalyst surface is controlled to 300 ° C. or lower. Even when a catalyst in which a copper compound is supported on aluminum is used, it is possible to suppress the progress of a reaction in which dimethyl ether is generated from methanol, and as a result, it is possible to maintain a high yield of hydrogen generation. it can.
  • FIG. 2 is an enlarged view showing a configuration of a reaction gas generation unit 2.
  • FIG. It is a graph which shows the relationship between the distance from the upstream edge part in the raw material gas flow direction in a reactor, and a catalyst surface temperature. It is a graph which shows the relationship between the linear velocity of raw material gas, and the maximum temperature of the catalyst surface in a reactor. It is a graph which shows the relationship between the temperature of the raw material gas just before flowing in into a reactor, and the maximum temperature of the catalyst surface in a reactor.
  • FIG. 1 is a process diagram showing a method for producing hydrogen according to an embodiment of the present invention.
  • FIG. 2 is a schematic diagram showing the configuration of a hydrogen production apparatus 100 for realizing the method for producing hydrogen according to the present invention.
  • FIG. 3 is an enlarged view showing the configuration of the reactive gas generator 2.
  • the method for producing hydrogen according to the present embodiment is a method for producing hydrogen by reacting methanol, water, and oxygen in the presence of a catalyst, and using a hydrogen production apparatus 100 shown in FIGS. To be implemented.
  • the hydrogen production apparatus 100 includes a source gas preparation unit 1, a reaction gas generation unit 2 having a reactor 2 ⁇ / b> A, a hydrogen gas separation unit 3, and a heat retention unit 4.
  • the hydrogen production method includes a raw material gas preparation step s1, a hydrogen generation step s2, a hydrogen gas separation step s3, and a residual gas combustion step s4.
  • the raw material gas preparation step s1 is a step for preparing a raw material gas containing at least methanol, water and oxygen adjusted to a predetermined reaction temperature, and is performed by the raw material gas preparation unit 1.
  • the source gas preparation step s1 includes a vaporization step s11 and an oxygen-containing gas mixing step s12.
  • a mixed gas containing methanol vapor and water vapor is generated by vaporizing methanol and water.
  • methanol and water are sent from the pump 5 to the raw material gas preparation unit 1 via the first pipe 6, for example.
  • the first pipe 6 is provided with a first valve 7 a and a second valve 7 b that open or close a flow path in the first pipe 6.
  • Methanol and water flow through the first pipe 6 from the pump 5 toward the source gas preparation unit 1 and are supplied to the source gas preparation unit 1 with the first valve 7 a and the second valve 7 b opened. .
  • a heat exchanger 8 may be provided between the pump 5 and the raw material gas preparation unit 1 as necessary.
  • the heat exchanger 8 When the heat exchanger 8 is provided, methanol and water can be heated by exchanging heat with a reaction gas obtained in the reaction gas generation unit 2 described later by the heat exchanger 8, and the reaction gas generation unit The reaction gas obtained in 2 can be cooled by heat exchange with methanol and water. Thereby, since methanol and water are heated beforehand before being sent to the raw material gas preparation part 1, methanol and water can be efficiently vaporized.
  • the amount of water per mole of methanol is preferably 1.2 moles or more, more preferably from the viewpoint of efficiently generating hydrogen gas and increasing the yield of hydrogen gas by reducing the residual amount of carbon monoxide gas. Is 1.5 mol or more.
  • the amount of water becomes too large, the yield of hydrogen gas does not improve so much, and from the viewpoint of increasing energy efficiency by reducing the amount of water with a large latent heat of evaporation, preferably 2.5 mol or less, more Preferably it is 2.0 mol or less.
  • the liquid temperature of the methanol and water sent to the raw material gas preparation unit 1 is not particularly limited and may be room temperature or higher than room temperature, but the hydrogen gas yield is improved. From the viewpoint of making it preferable, it is preferably as high as possible.
  • the upper limit temperature of the liquid temperature is preferably not more than the boiling point of methanol from the viewpoint of increasing energy efficiency.
  • methanol and water do not necessarily have to be heated and vaporized at the same time, methanol vaporization and water vaporization may be performed separately, or methanol and water are mixed and the mixture is vaporized. May be.
  • a metal tube having a spiral shape may be mentioned, but it is not limited to such an example.
  • the metal used for the metal tube include stainless steel and copper, brass and the like because of excellent thermal conductivity.
  • the raw material gas preparation unit 1 is disposed in a container-shaped heat retaining unit 4 so that heat generated by burning a residual gas described later in the gas combustion unit 9 can be efficiently transmitted. .
  • a mixed gas containing methanol vapor and water vapor obtained by vaporizing methanol and water flows through the second pipe 10 and is sent toward the reaction gas generation unit 2.
  • oxygen as a raw material for generating hydrogen gas is used as an oxygen-containing gas.
  • oxygen-containing gas include air, oxygen gas and the like, and mixed fluids of inert gas and oxygen gas such as nitrogen gas and argon gas.
  • inert gas is separable from hydrogen, It is not limited only to such illustration.
  • a mixed gas containing methanol vapor and water vapor flowing through the second pipe 10 and an oxygen-containing gas are mixed, and at least methanol, water, and oxygen are mixed.
  • a raw material gas to be contained is prepared. Note that the oxygen-containing gas has a small heat capacity compared to methanol and water, and thus does not need to be heated, but may be heated if necessary.
  • the amount of oxygen gas contained in the oxygen-containing gas per mole of methanol is preferably 0.05 moles or more, more preferably 0.08 moles or more, from the viewpoint of reducing the remaining amount of unreacted methanol. From the viewpoint of avoiding that the reaction temperature becomes high due to the reaction between the hydrogen gas generated from methanol and the introduced oxygen gas, and that the generated hydrogen gas is consumed by the reaction with oxygen gas, Preferably it is 0.20 mol or less, More preferably, it is 0.15 mol or less.
  • the oxygen-containing gas is sent toward the reaction gas generation unit 2 through the third pipe 11 provided with the third valve 13.
  • the oxygen-containing gas flows through the third pipe 11 in a state where the third valve 13 is opened, and is sent toward the reaction gas generation unit 2.
  • a second pipe 10 through which a mixed gas containing methanol vapor and water vapor flows and a third pipe 11 through which an oxygen-containing gas flows are connected to a fourth pipe 12, and the fourth pipe 12 generates a reaction gas. It is connected to the reactor 2A provided in the section 2.
  • the mixed gas flowing in the second pipe 10 and the oxygen-containing gas flowing in the third pipe 11 are mixed in the fourth pipe 12, thereby preparing a raw material gas containing at least methanol, water, and oxygen.
  • the raw material gas thus prepared flows through the fourth pipe 12 and is supplied to the reactor 2A.
  • the raw material gas that flows in the fourth pipe 12 and is supplied to the reactor 2A of the reaction gas generation unit 2 is allowed to proceed in a partial oxidation reaction and decomposition reaction of methanol in the presence of a catalyst,
  • the reactive gas generation unit 2 is disposed in the heat retaining unit 4.
  • the raw material gas supplied to the reaction gas generation unit 2 via the fourth pipe 12 is adjusted to a predetermined reaction possible temperature before flowing into the reactor 2A.
  • the temperature of the raw material gas is adjusted such that the temperature immediately before flowing into the reactor 2A (the inlet temperature of the reactor 2A) is the reaction possible temperature.
  • the temperature of the raw material gas immediately before flowing into the reactor 2A is preferably 200 ° C. or higher, more preferably 220 ° C. or higher, from the viewpoint of promoting the partial oxidation reaction of methanol and reducing the remaining amount of unreacted methanol. In view of the heat resistant temperature of the catalyst, it is preferably 300 ° C. or lower, more preferably 260 ° C. or lower.
  • a particulate catalyst is filled to form a catalyst layer.
  • the catalyst include a catalyst in which a copper compound is supported on aluminum oxide.
  • Specific examples include a catalyst in which copper is supported on aluminum oxide and a catalyst in which copper and zinc oxide are supported on aluminum oxide.
  • the mass ratio of copper (Cu) to aluminum oxide (Al 2 O 3 ) [copper (Cu) / aluminum oxide (Al 2 O 3 )] exhibits sufficient catalytic activity of copper (Cu) as an additive. From the viewpoint of making it possible, it is preferably 0.1 or more, and from the viewpoint of imparting sufficient mechanical strength to the added copper (Cu) and increasing the catalytic activity, it is preferably 1 or less.
  • a commercially available catalyst in which copper is supported on aluminum oxide or a catalyst in which copper and zinc oxide are supported on aluminum oxide is present in a state of copper oxide when purchased. In this state, since it does not show catalytic activity, it is preferable to use reduced copper.
  • the method for reducing copper oxide include a method in which a catalyst containing copper oxide is brought into contact with a reducing gas, but the present invention is not limited to such a method.
  • the reducing gas include hydrogen gas and a mixed gas of hydrogen gas and an inert gas such as nitrogen gas or argon gas.
  • the particle diameter of the catalyst in which copper is supported on aluminum oxide or the catalyst in which copper and zinc oxide are supported on aluminum oxide is preferably 1 mm or more, more preferably 3 mm or more, from the viewpoint of reducing the pressure loss of the catalyst layer. From the viewpoint of increasing the contact efficiency between the catalyst and methanol vapor, water vapor and oxygen-containing gas, it is preferably 20 mm or less, more preferably 10 mm or less.
  • the filling amount of the catalyst in which copper is supported on aluminum oxide or the catalyst in which copper and zinc oxide are supported on aluminum oxide is usually 35 ml or more per 1 g / min of methanol fed to the raw material gas preparation unit 1. Preferably there is.
  • the reactor 2A is a cylindrical body having a circular cross-sectional shape, and a columnar catalyst layer is formed by filling the inside of the cylindrical body with a catalyst. Further, the reactor 2A may be configured such that two cylindrical bodies having a circular cross-sectional shape are concentrically overlapped, and a catalyst is filled in a gap between the cylindrical bodies to form a cylindrical catalyst layer. . That is, the reactor 2A is formed in a cylindrical shape, and its internal space is filled with a catalyst.
  • the reactor 2A has the same inner diameter at one end in the axial direction and the other end, and has a shape extending longer in the axial direction than the inner diameter.
  • a cylindrical protective tube 2B extending along the axial line from one end to the other end in the axial direction is inserted into the reactor 2A in which the catalyst layer is formed by filling the catalyst, and this protective tube 2B is inserted into the protective tube 2B.
  • a temperature measuring member for measuring the surface temperature of the catalyst can be inserted.
  • the temperature measurement member can move in the protective tube 2B along the axis of the reactor 2A.
  • the temperature measured by the temperature measuring member moving in the protective tube 2B is different from the outer surface temperature of the reactor 2A, and is the temperature of the catalyst surface charged in the reactor 2A.
  • the reactor 2A may be provided with a cooling medium circulation pipe 2C serving as a refrigerant body for adjusting the temperature of the catalyst surface or a flow path for flowing a heating medium.
  • a cooling medium circulation pipe 2C serving as a refrigerant body for adjusting the temperature of the catalyst surface or a flow path for flowing a heating medium. Note that the cooling medium circulation pipe 2C is not necessarily provided.
  • the reactor 2A is formed so that the catalyst layer formed in the internal space has an (effective area (m 2 ) / length extending in the axial direction (m)) of 0.017 or more and 0.025 or less. It is preferred that Here, the effective area is an area obtained by subtracting the area of the protective tube 2B or the cooling medium circulation tube 2C from the total area of the surface of the catalyst layer perpendicular to the axis.
  • the surface temperature (maximum temperature) of the catalyst charged in the reactor 2A is preferably 250 ° C. or more from the viewpoint of efficiently reforming methanol into hydrogen, preventing catalyst deterioration, and suppressing the production of reaction byproducts. And from a viewpoint which suppresses that hydrogen and oxygen react, Preferably it is 300 degrees C or less. Further, the pressure in the reactor 2A is not particularly limited, but it is usually preferable that the gauge pressure is 0.2 to 1.5 MPa.
  • a partial oxidation reaction having a high reaction rate proceeds at a portion upstream of the raw material gas in the flow direction (one axial end side).
  • a decomposition reaction with a slow reaction rate proceeds on the downstream side in the flow direction (the other end in the axial direction).
  • the catalyst existing in the upstream portion of the reactor 2A in the flow direction of the raw material gas becomes high temperature exceeding 300 ° C. due to the influence of the partial oxidation reaction accompanied by heat generation.
  • a catalyst heated to a temperature exceeding 300 ° C. is deteriorated due to sintering, resulting in a decrease in activity and a short catalyst life.
  • the (effective area / axis line) of the catalyst layer formed in the internal space In order to solve the problems associated with the increase in the catalyst surface temperature as described above, in the hydrogen generation step s2 in the hydrogen production method of the present embodiment, the (effective area / axis line) of the catalyst layer formed in the internal space.
  • the flow rate of the raw material gas flowing in the reactor 2A is controlled, so that the surface of the catalyst with which the raw material gas contacts is controlled.
  • the maximum temperature is controlled to 300 ° C or lower. More specifically, in the hydrogen generation step s2, the raw material gas flowing in the reactor 2A is adjusted so that the linear velocity of the raw material gas flowing in the reactor 2A is 0.01 to 0.2 (Nm / s). Control the flow rate.
  • the linear velocity of the raw material gas flowing in the reactor 2A is 0.01 to 0.2 (Nm / s), and the spatial velocity of the raw material gas is 200 to 1500 (/ h). ) To control the flow rate of the raw material gas flowing in the reactor 2A.
  • the flow rate of the raw material gas flowing through the reactor 2A can be controlled by adjusting the flow rate of the liquid flow of methanol and water flowing through the first pipe 6 and the flow rate of the oxygen-containing gas flowing through the third pipe 11. .
  • the reaction rate difference between the partial oxidation reaction and the decomposition reaction is reduced by controlling the flow rate of the raw material gas flowing in the reactor 2A, and the reaction gas in the reactor 2A has a flow direction.
  • the partial oxidation reaction and the decomposition reaction proceed in substantially the same part of the above.
  • the heat generated in the partial oxidation reaction with exotherm is consumed in the decomposition reaction with endotherm, so that the catalyst charged in the reactor 2A is strongly influenced only by the partial oxidation reaction with exotherm.
  • the flow rate of the raw material gas flowing in the reactor 2A is controlled, and the maximum temperature on the catalyst surface is controlled to 300 ° C. or lower, so that a copper compound is supported on aluminum oxide. Even when the prepared catalyst is used, it is possible to suppress the progress of the reaction for producing dimethyl ether from methanol, and as a result, the production yield of hydrogen can be maintained at a high yield.
  • the reaction gas generated by the partial oxidation reaction and decomposition reaction of methanol in the reactor 2A includes, in addition to hydrogen gas, unreacted methanol vapor, carbon dioxide gas, carbon monoxide gas, water vapor, dimethyl ether, etc. Impurity gas is included.
  • the reaction gas generated in the reactor 2 ⁇ / b> A is supplied to the hydrogen gas separation unit 3 through the fifth pipe 14 and the sixth pipe 15.
  • a heat exchanger 8 is disposed between the fifth pipe 14 and the sixth pipe 15.
  • the reaction gas generated in the reactor 2 ⁇ / b> A and the raw materials methanol and water can be subjected to heat exchange, whereby the methanol and water can be efficiently heated. It can cool efficiently by exchanging heat with water.
  • the hydrogen gas separation step s3 is a step of separating hydrogen gas from the impurity gas from the reaction gas supplied to the hydrogen gas separation unit 3 through the fifth pipe 14 and the sixth pipe 15, and the hydrogen gas separation unit 3 To be implemented.
  • Examples of the hydrogen gas separation unit 3 include an adsorption tower filled with an adsorbent. Although only one adsorption tower may be used, it is preferable to use a plurality of, for example, about 2 to 5 from the viewpoint of efficiently producing high-purity hydrogen gas.
  • the adsorbent examples include carbon-based adsorbents when removing carbon dioxide, methanol, dimethyl ether, and the like, and zeolites and the like for removing carbon monoxide when removing carbon monoxide. In some cases, alumina or the like is used. Usually, these adsorbents are mixed and used for removing by adsorbing impurity gases such as vapor of unreacted methanol, carbon dioxide gas, carbon monoxide gas, water vapor, dimethyl ether and the like.
  • Hydrogen gas is separated by a pressure fluctuation adsorption apparatus (PSA). More specifically, for example, the separation can be performed according to the separation method described in JP-A-2004-66125.
  • PSA pressure fluctuation adsorption apparatus
  • the high-purity hydrogen gas obtained in the hydrogen gas separation step s3 is stored in the hydrogen gas storage tank 17 via the seventh pipe 16.
  • the obtained high-purity hydrogen gas can be promptly used on site.
  • the hydrogen gas storage tank 17 is not necessarily required.
  • the impurity gas adsorbed and removed by the hydrogen gas separation unit 3 remains in the hydrogen gas separation unit 3 by, for example, degassing the hydrogen gas separation unit 3 after the production of the hydrogen gas is stopped. It can be recovered as a residual gas.
  • the residual gas contains hydrogen gas in addition to impurity gas.
  • the residual gas is sent to the gas combustion unit 9 disposed in the heat retaining unit 4 through the eighth pipe 18.
  • the residual gas combustion step s4 is a step of burning the residual gas, and is performed by the gas combustion unit 9.
  • the residual gas is not disposed as waste gas or burned, but is burned in the gas combustion section 9 disposed in the heat retaining section 4 as described above, so that the residual gas is Make effective use.
  • a platinum catalyst is preferable because of its high catalytic activity and excellent heat resistance.
  • the platinum catalyst is preferably one in which platinum is supported on a carrier having a honeycomb structure. Metal honeycombs and ceramic honeycombs are used.
  • the platinum catalyst may be platinum particles, or may be one in which platinum is supported on a carrier such as alumina particles.
  • the catalyst for burning the residual gas include noble metals such as palladium, rhodium and silver, and compounds of these metals in addition to the platinum.
  • the amount of air is not particularly limited as long as the hydrogen gas contained in the residual gas is sufficiently combusted.
  • the heating temperature of methanol vapor and water vapor, which are reaction gases due to combustion heat generated when the residual gas is burned is preferably 250. From the viewpoint of suppressing catalyst deterioration, it is preferably 600 ° C. or lower.
  • Example 1 A catalyst in which copper oxide and zinc oxide are supported on aluminum oxide (Mitsubishi) in a cylindrical SUS304 reactor having a length of 1000 mm extending in the axial direction and an inner diameter of 154.4 mm and a temperature measuring protective tube installed in the center. After filling with Gas Chemical Co., MGC-MH1, particle size 3 mm), the copper oxide was reduced by introducing nitrogen gas containing 4 vol% of hydrogen gas into the reactor at about 21 Nm 3 / h for about 10 hours. . The reactor has an effective area (effective area (m 2 ) / length extending in the axial direction (m)) of 0.019.
  • Methanol and water were fed to the raw material gas preparation unit at flow rates of 218.5 g / min and 184.7 g / min, respectively, and vaporized in the raw material gas preparation unit to obtain a mixed gas containing methanol vapor and water vapor. .
  • This mixed gas was mixed with air (oxygen-containing gas) flowing at a flow rate of 68 L / min in the standard state (NTP) to form a raw material gas, and the raw material gas was introduced into the reactor.
  • the temperature of the raw material gas immediately before flowing into the reactor was controlled at 240 ° C.
  • the molar ratio of water / methanol was 1.5 / 1
  • the molar ratio of oxygen / methanol was 0.09 / 1.
  • the linear velocity (LV) of the raw material gas was 0.2 (Nm / s), the space velocity (SV) was 1230 (/ h), and the gauge pressure in the reactor was controlled to 0.8 MPa.
  • Example 2 The reaction was performed in the same manner as in Example 1 except that the linear velocity of the source gas was 0.04 (Nm / s) and the space velocity was 250 (/ h).
  • Example 2 The reaction was carried out in the same manner as in Example 1 except that the linear velocity of the source gas was 0.4 (Nm / s) and the space velocity was 425 (/ h).
  • FIGS. 4 and 5 Evaluation results are shown in FIGS. 4 and 5 and Table 1.
  • FIG. 4 is a graph showing the relationship between the distance from the upstream end portion in the raw material gas flow direction in the reactor and the catalyst surface temperature.
  • FIG. 5 is a graph showing the relationship between the linear velocity of the raw material gas and the maximum temperature of the catalyst surface in the reactor.
  • the catalyst present in the portion having a short distance from the upstream end portion in the raw material gas flow direction becomes high temperature due to the influence of the partial oxidation reaction of methanol accompanied by heat generation.
  • the maximum temperature on the catalyst surface in Example 1 was 293 ° C.
  • the maximum temperature on the catalyst surface in Example 2 was 262 ° C.
  • the maximum temperature on the catalyst surface was 300 ° C. or lower.
  • the maximum temperature on the catalyst surface in Comparative Example 1 is 391 ° C.
  • the maximum temperature on the catalyst surface in Comparative Example 2 is 331 ° C.
  • the maximum temperature on the catalyst surface is 300 ° C. It was over temperature.
  • the temperature of such a catalyst surface can be controlled by the flow rate of the raw material gas in the reactor.
  • the linear velocity of the raw material gas is 0.01 to 0.2 (Nm / s). Since the flow rate of the raw material gas flowing in the reactor is controlled so that the space velocity is in the range of 200 to 1500 (/ h) within the range, the maximum temperature on the catalyst surface is 300 ° C or less. Can be controlled.
  • Examples 1 and 2 contain hydrogen gas that suppresses the generation of DME as a by-product after consuming all of the raw material methanol charged into the reactor. It can be seen that the reaction gas can be produced.
  • the maximum temperature on the catalyst surface is a low state of 300 ° C. or lower, it is expected that the catalyst life can be extended and hydrogen can be produced stably over a long period of time. It is.
  • Comparative Examples 1 and 2 all of the raw material methanol charged into the reactor was consumed, but it can be seen that by-product dimethyl ether increased as the reaction temperature increased. In Comparative Examples 1 and 2, since the maximum temperature on the catalyst surface is in a high temperature state exceeding 300 ° C., the catalyst life may be shortened.
  • Example 3 The reaction was carried out in the same manner as in Example 2 except that the temperature of the raw material gas immediately before flowing into the reactor was controlled at 220 ° C.
  • Example 4 The reaction was carried out in the same manner as in Example 2 except that the temperature of the raw material gas immediately before flowing into the reactor was controlled at 260 ° C.
  • FIG. 6 is a graph showing the relationship between the temperature of the raw material gas immediately before flowing into the reactor and the maximum temperature of the catalyst surface in the reactor.
  • the maximum temperature of the catalyst surface charged in the reactor is controlled by controlling the temperature of the raw material gas immediately before flowing into the reactor within the range of 220 to 260 ° C. It can be seen that the temperature can be controlled to 300 ° C. or lower.

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Abstract

The present invention is a method for producing hydrogen by allowing a partial oxidation reaction and decomposition reaction of methanol to proceed in order to generate hydrogen, wherein it is possible to extend catalyst service life and to stably produce hydrogen over the long term. The method for producing hydrogen includes a starting material gas preparation step (s1) and a hydrogen generation step (s2). In the starting material gas preparation step (s1), a starting material gas containing methanol, water, and oxygen and adjusted to a predetermined reactable temperature is prepared. In the hydrogen generation step (s2), the starting material gas that has been adjusted to the reactable temperature is caused to flow through the inside of a reactor (2A) that is filled with a particulate catalyst, causing contact with the catalyst, and thereby allowing a partial oxidation reaction and decomposition reaction of methanol to proceed, generation hydrogen. In the hydrogen generation step (s2), the highest temperature of the catalyst surface contacting the starting material gas is controlled to be no greater than 300°C by means of controlling the flow rate of starting material gas flowing within the reactor (2A).

Description

水素の製造方法Method for producing hydrogen
　本発明は、水素の製造方法に関する。さらに詳しくは、メタノールと、水および酸素とを、触媒の存在下で反応させることによって水素を生成する水素の製造方法に関する。 The present invention relates to a method for producing hydrogen. More specifically, the present invention relates to a method for producing hydrogen in which hydrogen is produced by reacting methanol with water and oxygen in the presence of a catalyst.
　メタノールは、輸送や貯蔵が容易なエネルギー源であり、オンサイトで水素ガスを発生させるための原料として使用されている。メタノールから水素ガスを製造する方法として、一般に、水蒸気改質法と部分酸化－水蒸気改質反応法が知られている。 Methanol is an energy source that can be easily transported and stored, and is used as a raw material for generating hydrogen gas on-site. As a method for producing hydrogen gas from methanol, a steam reforming method and a partial oxidation-steam reforming reaction method are generally known.
　水蒸気改質法は、メタノール蒸気を触媒の存在下で水蒸気と接触させることによって水素ガスを製造する方法である。この水蒸気改質法は、比較的大きな吸熱を伴う反応であるため、熱交換器などの熱の供給システムの負荷が大きく、起動に時間が掛かるなどの欠点がある。 The steam reforming method is a method for producing hydrogen gas by bringing methanol vapor into contact with steam in the presence of a catalyst. Since this steam reforming reaction involves a relatively large endotherm, there is a drawback that the heat supply system such as a heat exchanger has a heavy load and takes a long time to start.
　一方、部分酸化－水蒸気改質反応法は、メタノール蒸気を触媒の存在下で水蒸気および酸素と接触させて水素ガスを製造する方法である。この部分酸化－水蒸気改質反応法は、メタノールを部分的に酸化（部分酸化反応）させて二酸化炭素と水素とする際に発生する熱を、メタノール蒸気と水蒸気を接触させる水蒸気改質によって二酸化炭素と水素に改質する吸熱反応（メタノールの分解反応）に利用するため、熱交換器などの熱の供給システムの負荷を小さくすることができるという利点がある。 On the other hand, the partial oxidation-steam reforming reaction method is a method for producing hydrogen gas by bringing methanol vapor into contact with steam and oxygen in the presence of a catalyst. In this partial oxidation-steam reforming reaction method, the heat generated when methanol is partially oxidized (partial oxidation reaction) to form carbon dioxide and hydrogen is converted into carbon dioxide by steam reforming in which methanol vapor and steam are brought into contact. Therefore, there is an advantage that the load of a heat supply system such as a heat exchanger can be reduced.
　しかしながら、部分酸化－水蒸気改質反応法では、発熱反応である部分酸化反応と、吸熱反応である水蒸気改質反応（分解反応）とが同時に進行するのではなく、部分酸化反応に対してやや遅れて水蒸気改質反応（分解反応）が進行するので、反応器内の温度制御が難しいという欠点がある。 However, in the partial oxidation-steam reforming reaction method, the partial oxidation reaction, which is an exothermic reaction, and the steam reforming reaction (decomposition reaction), which is an endothermic reaction, do not proceed at the same time, but are slightly delayed from the partial oxidation reaction. Since the steam reforming reaction (decomposition reaction) proceeds, there is a drawback that it is difficult to control the temperature in the reactor.
　この点について、詳細に説明すると、メタノール、水および酸素を含む原料ガスが供給される、触媒が充填された反応器において、原料ガスの流れ方向上流側の部分で、反応速度の速い部分酸化反応が進行し、原料ガスの流れ方向下流側の部分で、反応速度の遅い水蒸気改質反応（分解反応）が進行する。その結果、反応器における、原料ガスの流れ方向上流側の部分に存在する触媒が、発熱を伴う部分酸化反応の影響を受けて高温になる。このようにして高温になった触媒は、シンタリングが発生して劣化し、活性が低下してしまう。 This point will be described in detail. In a reactor filled with a catalyst, to which a raw material gas containing methanol, water and oxygen is supplied, a partial oxidation reaction having a high reaction rate in a portion upstream of the flow direction of the raw material gas. And a steam reforming reaction (decomposition reaction) with a slow reaction rate proceeds in the downstream portion of the flow direction of the raw material gas. As a result, the catalyst existing in the upstream portion of the reactor in the flow direction of the raw material gas becomes high temperature under the influence of the partial oxidation reaction accompanied by heat generation. Thus, the catalyst which became high temperature will generate | occur | produce a sintering, will deteriorate, and activity will fall.
　部分酸化－水蒸気改質反応法による水素の製造方法において、上記のような問題点を解決するための方法が、種々提案されている。 Various methods for solving the above problems have been proposed in the method for producing hydrogen by the partial oxidation-steam reforming reaction method.
　たとえば、特許文献１には、部分酸化－水蒸気改質反応法による水素の製造方法において、酸化アルミニウムに酸化銅が担持された触媒を用いるとともに、発熱を伴う部分酸化反応の原料となる酸素を含有する酸素含有ガスの、反応器に対する供給を一時的に停止する方法が開示されている。 For example, Patent Document 1 uses a catalyst in which copper oxide is supported on aluminum oxide in a method for producing hydrogen by a partial oxidation-steam reforming reaction method, and contains oxygen as a raw material for a partial oxidation reaction that generates heat. A method for temporarily stopping the supply of oxygen-containing gas to the reactor is disclosed.
　また、特許文献２には、部分酸化－水蒸気改質反応法による水素の製造方法において、発熱を伴う部分酸化反応が主として進行する、反応器における原料ガスの流れ方向上流側の部分での原料ガスの流速を速くする方法が開示されている。 Further, Patent Document 2 discloses a raw material gas at a portion upstream of the flow direction of a raw material gas in a reactor in which a partial oxidation reaction accompanied by heat generation mainly proceeds in a method for producing hydrogen by a partial oxidation-steam reforming reaction method. A method for increasing the flow rate of the liquid is disclosed.
国際公開ＷＯ２０１２／１０５３５５号International Publication WO2012 / 105355 特開平１１－９２１０２号公報JP-A-11-92102
　しかしながら、特許文献１，２に開示される方法では、発熱を伴う部分酸化反応と、吸熱を伴う水蒸気改質反応（分解反応）との反応速度差が十分に小さくなるには至らずに、反応速度の速い部分酸化反応が、反応器における原料ガスの流れ方向上流側の部分で進行し、反応速度の遅い分解反応が、反応器における原料ガスの流れ方向下流側の部分で進行することになる。 However, in the methods disclosed in Patent Documents 1 and 2, the reaction rate difference between the partial oxidation reaction with exotherm and the steam reforming reaction (decomposition reaction) with endotherm does not become sufficiently small. A fast partial oxidation reaction proceeds in a portion upstream of the raw material gas in the reactor in the flow direction, and a decomposition reaction having a slow reaction speed proceeds in a portion downstream of the raw material gas in the reactor in the flow direction.
　たとえば、特許文献２には、反応器における原料ガスの流れ方向上流側の部分での原料ガスの流速を速くすることによって、メタルハニカム構造を有する反応器の温度分布を２５０～３００℃に制御可能であることが記載されているが、この温度はあくまでも、熱伝導性の高いメタルからなるメタルハニカムの外部温度である。部分酸化反応と分解反応との反応速度差が十分に小さくなるには至らない、特許文献２に開示される方法では、発熱を伴う部分酸化反応が進行する、反応器における原料ガスの流れ方向上流側の部分に存在する触媒の表面温度は、高熱伝導性を有するメタルハニカムの温度よりも高い、３００℃を超える温度になっていると考えるのが妥当である。 For example, in Patent Document 2, the temperature distribution of a reactor having a metal honeycomb structure can be controlled to 250 to 300 ° C. by increasing the flow rate of the source gas in the upstream portion of the reactor in the flow direction of the source gas. However, this temperature is only an external temperature of a metal honeycomb made of a metal having high thermal conductivity. In the method disclosed in Patent Document 2 in which the difference in reaction rate between the partial oxidation reaction and the decomposition reaction does not become sufficiently small, the partial oxidation reaction accompanied by heat generation proceeds, on the upstream side in the flow direction of the raw material gas in the reactor. It is reasonable to think that the surface temperature of the catalyst present in the portion is higher than 300 ° C., which is higher than the temperature of the metal honeycomb having high thermal conductivity.
　３００℃を超える温度にまで加熱された触媒は、シンタリングが発生して劣化し、活性が低下してしまう。すなわち、特許文献１，２に開示される方法では、触媒寿命が短いものとなり、水素を長期間にわたって安定して製造することができない。 The catalyst heated to a temperature exceeding 300 ° C. deteriorates due to sintering, resulting in a decrease in activity. In other words, the methods disclosed in Patent Documents 1 and 2 have a short catalyst life, and hydrogen cannot be produced stably over a long period of time.
　本発明の目的は、メタノールの部分酸化反応および分解反応を進行させて水素を生成する水素の製造方法において、触媒寿命を延ばすことができるとともに、水素を長期間にわたって安定して製造することができる製造方法を提供することである。 An object of the present invention is to increase the catalyst life and stably produce hydrogen over a long period of time in a hydrogen production method in which hydrogen is produced by a partial oxidation reaction and decomposition reaction of methanol. It is to provide a manufacturing method.
　本発明は、メタノール、水および酸素を含む原料ガスを、予め定める反応可能温度に調整する温度調整工程と、
　前記反応可能温度に調整された原料ガスを、粒子状の触媒が充填された反応器内に流過させて触媒と接触させることによって、メタノールの部分酸化反応および分解反応を進行させて、水素を生成する水素生成工程と、を含み、
　前記水素生成工程では、反応器内を流過する原料ガスの流量を制御することによって、メタノールの部分酸化反応および分解反応の進行中における、原料ガスが接触する触媒表面の最高温度を３００℃以下に制御することを特徴とする水素の製造方法である。 The present invention includes a temperature adjustment step of adjusting a raw material gas containing methanol, water, and oxygen to a predetermined reactionable temperature;
The raw material gas adjusted to the reaction possible temperature is caused to flow through a reactor filled with a particulate catalyst and brought into contact with the catalyst, thereby causing the partial oxidation reaction and decomposition reaction of methanol to proceed, thereby allowing hydrogen to flow. A hydrogen production step to produce,
In the hydrogen generation step, by controlling the flow rate of the raw material gas flowing through the reactor, the maximum temperature of the catalyst surface in contact with the raw material gas during the partial oxidation reaction and decomposition reaction of methanol is 300 ° C. or less. It is the manufacturing method of hydrogen characterized by controlling to.
　また本発明の水素の製造方法において、前記水素生成工程では、反応器内を流過する原料ガスの線速度が０．０１～０．２（Ｎｍ／ｓ）となるように、原料ガスの流量を制御することが好ましい。 In the hydrogen production method of the present invention, in the hydrogen generation step, the flow rate of the raw material gas is adjusted so that the linear velocity of the raw material gas flowing through the reactor is 0.01 to 0.2 (Nm / s). Is preferably controlled.
　また本発明の水素の製造方法において、前記水素生成工程では、反応器内を流過する原料ガスの空間速度が２００～１５００（／ｈ）となるように、原料ガスの流量を制御することが好ましい。 In the hydrogen production method of the present invention, in the hydrogen generation step, the flow rate of the source gas may be controlled so that the space velocity of the source gas flowing through the reactor is 200 to 1500 (/ h). preferable.
　また本発明の水素の製造方法において、前記触媒は、酸化アルミニウムに銅系化合物が担持された触媒であることが好ましい。 In the hydrogen production method of the present invention, the catalyst is preferably a catalyst in which a copper compound is supported on aluminum oxide.
　本発明によれば、水素の製造方法は、温度調整工程と水素生成工程とを含む。温度調整工程では、メタノール、水および酸素を含む原料ガスを、予め定める反応可能温度に調整する。水素生成工程では、反応可能温度に調整された原料ガスを、粒子状の触媒が充填された反応器内に流過させて触媒と接触させる。このように原料ガスが触媒と接触すると、メタノールと酸素とによる部分酸化反応、および、メタノールと水とによる分解反応が進行する。 According to the present invention, the method for producing hydrogen includes a temperature adjustment step and a hydrogen generation step. In the temperature adjustment step, the raw material gas containing methanol, water and oxygen is adjusted to a predetermined reaction temperature. In the hydrogen generation step, the raw material gas adjusted to the reaction possible temperature is caused to flow through the reactor filled with the particulate catalyst and brought into contact with the catalyst. When the source gas comes into contact with the catalyst in this manner, a partial oxidation reaction with methanol and oxygen and a decomposition reaction with methanol and water proceed.
　本発明の水素の製造方法において、発熱を伴う部分酸化反応と、吸熱を伴う分解反応とを進行させる水素生成工程では、反応器内を流過する原料ガスの流量を制御することによって、原料ガスが接触する触媒表面の最高温度を３００℃以下に制御する。 In the hydrogen production method of the present invention, in the hydrogen generation step in which the partial oxidation reaction with exotherm and the decomposition reaction with endotherm proceed, the source gas is controlled by controlling the flow rate of the source gas flowing through the reactor. Is controlled to 300 ° C. or lower.
　部分酸化反応と分解反応との反応速度差と、触媒表面の最高温度との間には、密接な関係が存在し、反応速度差が小さい場合には、触媒表面の最高温度を３００℃以下に制御することができる。 A close relationship exists between the reaction rate difference between the partial oxidation reaction and the decomposition reaction and the maximum temperature on the catalyst surface. When the reaction rate difference is small, the maximum temperature on the catalyst surface is set to 300 ° C. or lower. Can be controlled.
　この点について、詳細に説明すると、通常、原料ガスが流過する、触媒が充填された反応器において、原料ガスの流れ方向上流側の部分で、反応速度の速い部分酸化反応が進行し、原料ガスの流れ方向下流側の部分で、反応速度の遅い分解反応が進行する。このような反応現象に対して、本発明の水素の製造方法では、反応器内を流過する原料ガスの流量を制御することによって部分酸化反応と分解反応との反応速度差を小さくし、原料ガスの流れ方向に関して反応器内のほぼ同一部分で、部分酸化反応と分解反応とが進行する。その結果、反応器内に充填される触媒において、発熱を伴う部分酸化反応のみの影響を強く受けて、過度に温度上昇する部分が発生するのを抑制することができ、触媒表面の最高温度を３００℃以下に制御することができる。したがって、本発明の水素の製造方法によれば、シンタリングによる劣化を抑制して触媒寿命を延ばすことができるとともに、水素を長期間にわたって安定して製造することができる。 This point will be described in detail. In a reactor filled with a catalyst, in which the raw material gas normally flows, a partial oxidation reaction with a high reaction rate proceeds in the upstream portion of the raw material gas in the flow direction. A decomposition reaction with a slow reaction rate proceeds in a portion downstream of the gas flow direction. For such a reaction phenomenon, in the method for producing hydrogen of the present invention, the reaction rate difference between the partial oxidation reaction and the decomposition reaction is reduced by controlling the flow rate of the raw material gas flowing through the reactor, and the raw material The partial oxidation reaction and the decomposition reaction proceed in substantially the same part in the reactor with respect to the gas flow direction. As a result, the catalyst filled in the reactor is strongly affected only by the partial oxidation reaction with exotherm, and it is possible to suppress the occurrence of an excessively high temperature portion, and the maximum temperature of the catalyst surface can be reduced. It can be controlled to 300 ° C. or lower. Therefore, according to the method for producing hydrogen of the present invention, deterioration due to sintering can be suppressed and the catalyst life can be extended, and hydrogen can be produced stably over a long period of time.
　また本発明によれば、水素生成工程では、反応器内を流過する原料ガスの線速度が０．０１～０．２（Ｎｍ／ｓ）となるように、原料ガスの流量を制御する。このように反応器内を流過する原料ガスの流量を制御することによって、部分酸化反応と分解反応との反応速度差を確実に小さくすることができ、原料ガスの流れ方向に関して反応器内のほぼ同一部分で、部分酸化反応と分解反応とを進行させることができる。その結果、触媒表面の最高温度を、より確実に３００℃以下に制御することができるので、触媒寿命を延ばすことができるとともに、水素を長期間にわたって安定して製造することができる。 Further, according to the present invention, in the hydrogen generation step, the flow rate of the raw material gas is controlled so that the linear velocity of the raw material gas flowing through the reactor becomes 0.01 to 0.2 (Nm / s). By controlling the flow rate of the raw material gas flowing through the reactor in this way, the reaction rate difference between the partial oxidation reaction and the decomposition reaction can be reliably reduced, and the flow rate of the raw material gas in the reactor can be reduced. The partial oxidation reaction and the decomposition reaction can proceed in substantially the same part. As a result, the maximum temperature of the catalyst surface can be more reliably controlled to 300 ° C. or lower, so that the catalyst life can be extended and hydrogen can be produced stably over a long period of time.
　また本発明によれば、水素生成工程では、反応器内を流過する原料ガスの線速度が０．０１～０．２（Ｎｍ／ｓ）であり、かつ、空間速度が２００～１５００（／ｈ）となるように、原料ガスの流量を制御する。このように反応器内を流過する原料ガスの流量を制御することによって、部分酸化反応と分解反応との反応速度差を確実に小さくすることができ、原料ガスの流れ方向に関して反応器内のほぼ同一部分で、部分酸化反応と分解反応とを進行させることができる。その結果、触媒表面の最高温度を、より確実に３００℃以下に制御することができるので、触媒寿命を延ばすことができるとともに、水素を長期間にわたって安定して製造することができる。 Further, according to the present invention, in the hydrogen generation step, the linear velocity of the raw material gas flowing through the reactor is 0.01 to 0.2 (Nm / s) and the space velocity is 200 to 1500 (/ h) The flow rate of the source gas is controlled so that By controlling the flow rate of the raw material gas flowing through the reactor in this way, the reaction rate difference between the partial oxidation reaction and the decomposition reaction can be reliably reduced, and the flow rate of the raw material gas in the reactor can be reduced. The partial oxidation reaction and the decomposition reaction can proceed in substantially the same part. As a result, the maximum temperature of the catalyst surface can be more reliably controlled to 300 ° C. or lower, so that the catalyst life can be extended and hydrogen can be produced stably over a long period of time.
　また本発明によれば、反応器に充填される触媒として、酸化アルミニウムに銅系化合物が担持された触媒を用いる。この触媒は、触媒活性の低下が抑制されるという点で優れている。しかしながら、この触媒を構成する酸化アルミニウムは、３００℃を超える高温状態では、メタノールからジメチルエーテルを生成する機能を有する。すなわち、酸化アルミニウムに銅系化合物が担持された触媒を用いた場合には、触媒の表面温度が３００℃を超えると、メタノールからジメチルエーテルが生成する反応が進行してしまい、水素を生成するためのメタノール量が低下することになり、水素の生成収率の低下を招くことになる。このような反応現象に対して、本発明の水素の製造方法では、反応器内を流過する原料ガスの流量が制御されて、触媒表面の最高温度が３００℃以下に制御されるので、酸化アルミニウムに銅系化合物が担持された触媒を用いても、メタノールからジメチルエーテルが生成する反応が進行するのを抑制することができ、その結果、水素の生成収率を高収率に維持することができる。 In addition, according to the present invention, a catalyst in which a copper compound is supported on aluminum oxide is used as the catalyst charged in the reactor. This catalyst is excellent in that a decrease in catalytic activity is suppressed. However, the aluminum oxide constituting this catalyst has a function of producing dimethyl ether from methanol at a high temperature exceeding 300 ° C. That is, when a catalyst in which a copper compound is supported on aluminum oxide is used, when the surface temperature of the catalyst exceeds 300 ° C., a reaction in which dimethyl ether is generated from methanol proceeds to generate hydrogen. The amount of methanol will decrease, leading to a decrease in hydrogen production yield. For such a reaction phenomenon, in the hydrogen production method of the present invention, the flow rate of the raw material gas flowing through the reactor is controlled, and the maximum temperature of the catalyst surface is controlled to 300 ° C. or lower. Even when a catalyst in which a copper compound is supported on aluminum is used, it is possible to suppress the progress of a reaction in which dimethyl ether is generated from methanol, and as a result, it is possible to maintain a high yield of hydrogen generation. it can.
　本発明の目的、特色、および利点は、下記の詳細な説明と図面とからより明確になるであろう。 The objects, features and advantages of the present invention will become more apparent from the following detailed description and drawings.
本発明の一実施形態に係る水素の製造方法を示す工程図である。It is process drawing which shows the manufacturing method of hydrogen which concerns on one Embodiment of this invention. 本発明に係る水素の製造方法を実現するための水素製造装置１００の構成を示す概略図である。It is the schematic which shows the structure of the hydrogen production apparatus 100 for implement | achieving the manufacturing method of hydrogen which concerns on this invention. 反応ガス生成部２の構成を拡大して示す図である。2 is an enlarged view showing a configuration of a reaction gas generation unit 2. FIG. 反応器における原料ガス流れ方向上流側端部からの距離と、触媒表面温度との関係を示すグラフである。It is a graph which shows the relationship between the distance from the upstream edge part in the raw material gas flow direction in a reactor, and a catalyst surface temperature. 原料ガスの線速度と、反応器内における触媒表面の最高温度との関係を示すグラフである。It is a graph which shows the relationship between the linear velocity of raw material gas, and the maximum temperature of the catalyst surface in a reactor. 反応器内に流入する直前の原料ガスの温度と、反応器内における触媒表面の最高温度との関係を示すグラフである。It is a graph which shows the relationship between the temperature of the raw material gas just before flowing in into a reactor, and the maximum temperature of the catalyst surface in a reactor.
　以下図面を参考にして本発明の好適な実施形態を詳細に説明する。
　図１は、本発明の一実施形態に係る水素の製造方法を示す工程図である。図２は、本発明に係る水素の製造方法を実現するための水素製造装置１００の構成を示す概略図である。図３は、反応ガス生成部２の構成を拡大して示す図である。 Preferred embodiments of the present invention will be described below in detail with reference to the drawings.
FIG. 1 is a process diagram showing a method for producing hydrogen according to an embodiment of the present invention. FIG. 2 is a schematic diagram showing the configuration of a hydrogen production apparatus 100 for realizing the method for producing hydrogen according to the present invention. FIG. 3 is an enlarged view showing the configuration of the reactive gas generator 2.
　本実施形態に係る水素の製造方法は、メタノールと、水および酸素とを、触媒の存在下で反応させることによって水素を生成する方法であり、図２，３に示す水素製造装置１００を用いて実施される。水素製造装置１００は、原料ガス調製部１と、反応器２Ａを有する反応ガス生成部２と、水素ガス分離部３と、保熱部４とを備える。 The method for producing hydrogen according to the present embodiment is a method for producing hydrogen by reacting methanol, water, and oxygen in the presence of a catalyst, and using a hydrogen production apparatus 100 shown in FIGS. To be implemented. The hydrogen production apparatus 100 includes a source gas preparation unit 1, a reaction gas generation unit 2 having a reactor 2 </ b> A, a hydrogen gas separation unit 3, and a heat retention unit 4.
　本実施形態に係る水素の製造方法は、原料ガス調製工程ｓ１と、水素生成工程ｓ２と、水素ガス分離工程ｓ３と、残存ガス燃焼工程ｓ４とを含む。 The hydrogen production method according to the present embodiment includes a raw material gas preparation step s1, a hydrogen generation step s2, a hydrogen gas separation step s3, and a residual gas combustion step s4.
　原料ガス調製工程ｓ１は、予め定める反応可能温度に調整された、少なくともメタノール、水および酸素を含有する原料ガスを調製するための工程であり、原料ガス調製部１により実施される。原料ガス調製工程ｓ１は、気化工程ｓ１１と酸素含有ガス混合工程ｓ１２とを含む。 The raw material gas preparation step s1 is a step for preparing a raw material gas containing at least methanol, water and oxygen adjusted to a predetermined reaction temperature, and is performed by the raw material gas preparation unit 1. The source gas preparation step s1 includes a vaporization step s11 and an oxygen-containing gas mixing step s12.
　原料ガス調製工程ｓ１の気化工程ｓ１１では、メタノールおよび水を気化させることによって、メタノール蒸気と水蒸気とを含む混合ガスを生成する。メタノールおよび水は、図２に示されるように、たとえば、ポンプ５から第１配管６を介して原料ガス調製部１に送液される。第１配管６には、第１配管６における流路を開放または閉鎖する第１バルブ７ａおよび第２バルブ７ｂが設けられている。メタノールおよび水は、第１バルブ７ａおよび第２バルブ７ｂが開放された状態で、ポンプ５から原料ガス調製部１に向けて第１配管６内を流れて、原料ガス調製部１に供給される。 In the vaporization step s11 of the raw material gas preparation step s1, a mixed gas containing methanol vapor and water vapor is generated by vaporizing methanol and water. As shown in FIG. 2, methanol and water are sent from the pump 5 to the raw material gas preparation unit 1 via the first pipe 6, for example. The first pipe 6 is provided with a first valve 7 a and a second valve 7 b that open or close a flow path in the first pipe 6. Methanol and water flow through the first pipe 6 from the pump 5 toward the source gas preparation unit 1 and are supplied to the source gas preparation unit 1 with the first valve 7 a and the second valve 7 b opened. .
　ポンプ５と原料ガス調製部１との間には、必要に応じて、熱交換器８が配設されていてもよい。熱交換器８を配設した場合、メタノールおよび水は、熱交換器８により、後述の反応ガス生成部２で得られた反応ガスと熱交換することによって加熱することができ、反応ガス生成部２で得られた反応ガスは、メタノールおよび水と熱交換することによって冷却することができる。これにより、メタノールおよび水は、原料ガス調製部１に送液される前に予め加熱されるので、効率よくメタノールおよび水を気化することができる。 A heat exchanger 8 may be provided between the pump 5 and the raw material gas preparation unit 1 as necessary. When the heat exchanger 8 is provided, methanol and water can be heated by exchanging heat with a reaction gas obtained in the reaction gas generation unit 2 described later by the heat exchanger 8, and the reaction gas generation unit The reaction gas obtained in 2 can be cooled by heat exchange with methanol and water. Thereby, since methanol and water are heated beforehand before being sent to the raw material gas preparation part 1, methanol and water can be efficiently vaporized.
　メタノール１モルあたりの水の量は、水素ガスを効率よく生成させるとともに一酸化炭素ガスの残存量を低減させることによって水素ガスの収率を高める観点から、好ましくは１．２モル以上、より好ましくは１．５モル以上である。また、水の量が多くなり過ぎても水素ガスの収率があまり向上せず、蒸発潜熱が大きい水の量を低減させることによってエネルギー効率を高める観点から、好ましくは２．５モル以下、より好ましくは２．０モル以下である。 The amount of water per mole of methanol is preferably 1.2 moles or more, more preferably from the viewpoint of efficiently generating hydrogen gas and increasing the yield of hydrogen gas by reducing the residual amount of carbon monoxide gas. Is 1.5 mol or more. In addition, even if the amount of water becomes too large, the yield of hydrogen gas does not improve so much, and from the viewpoint of increasing energy efficiency by reducing the amount of water with a large latent heat of evaporation, preferably 2.5 mol or less, more Preferably it is 2.0 mol or less.
　なお、原料ガス調製部１に送液されるメタノールおよび水の液温は、特に限定されず、常温であってもよく、常温よりも高温であってもよいが、水素ガスの収率を向上させる観点から、できるだけ高いことが好ましい。前記液温の上限温度は、エネルギー効率を高める観点から、好ましくはメタノールの沸点以下である。 In addition, the liquid temperature of the methanol and water sent to the raw material gas preparation unit 1 is not particularly limited and may be room temperature or higher than room temperature, but the hydrogen gas yield is improved. From the viewpoint of making it preferable, it is preferably as high as possible. The upper limit temperature of the liquid temperature is preferably not more than the boiling point of methanol from the viewpoint of increasing energy efficiency.
　また、メタノールと水とは、必ずしも同時に加熱して気化させる必要がなく、メタノールの気化と水の気化とを別々に行ってもよく、あるいはメタノールと水とを混合し、その混合液を気化させてもよい。 In addition, methanol and water do not necessarily have to be heated and vaporized at the same time, methanol vaporization and water vaporization may be performed separately, or methanol and water are mixed and the mixture is vaporized. May be.
　原料ガス調製部１としては、たとえば、図１に示されるように、螺旋形状を有する金属管などが挙げられるが、かかる例示のみに限定されるものではない。金属管に用いられる金属としては、たとえば、ステンレス鋼をはじめ、熱伝導性に優れていることから、銅、黄銅などが挙げられる。原料ガス調製部１は、後述する残存ガスをガス燃焼部９で燃焼することによって生じた熱が効率よく伝達されるようにするために、容器状の保熱部４内に配設されている。 As the source gas preparation unit 1, for example, as shown in FIG. 1, a metal tube having a spiral shape may be mentioned, but it is not limited to such an example. Examples of the metal used for the metal tube include stainless steel and copper, brass and the like because of excellent thermal conductivity. The raw material gas preparation unit 1 is disposed in a container-shaped heat retaining unit 4 so that heat generated by burning a residual gas described later in the gas combustion unit 9 can be efficiently transmitted. .
　原料ガス調製部１において、メタノールおよび水が気化することによって得られたメタノール蒸気と水蒸気とを含有する混合ガスは、第２配管１０内を流れて、反応ガス生成部２に向けて送気される。 In the raw material gas preparation unit 1, a mixed gas containing methanol vapor and water vapor obtained by vaporizing methanol and water flows through the second pipe 10 and is sent toward the reaction gas generation unit 2. The
　水素ガスを生成するための原料としての酸素は、本実施形態では、酸素含有ガスとして用いられる。酸素含有ガスとしては、たとえば、空気、酸素ガスなどをはじめ、窒素ガス、アルゴンガスなどの不活性ガスと酸素ガスとの混合流体などが挙げられるが、水素と分離が可能な不活性ガスなら、かかる例示のみに限定されるものではない。 In the present embodiment, oxygen as a raw material for generating hydrogen gas is used as an oxygen-containing gas. Examples of the oxygen-containing gas include air, oxygen gas and the like, and mixed fluids of inert gas and oxygen gas such as nitrogen gas and argon gas. However, if the inert gas is separable from hydrogen, It is not limited only to such illustration.
　原料ガス調製工程ｓ１の酸素含有ガス混合工程ｓ１２では、第２配管１０内を流れる、メタノール蒸気と水蒸気とを含有する混合ガスと、酸素含有ガスとを混合して、少なくともメタノール、水および酸素を含有する原料ガスを調製する。なお、酸素含有ガスは、メタノールおよび水と対比して熱容量が小さいので、特に加熱しなくてもよいが、必要により、加熱してもよい。 In the oxygen-containing gas mixing step s12 of the raw material gas preparation step s1, a mixed gas containing methanol vapor and water vapor flowing through the second pipe 10 and an oxygen-containing gas are mixed, and at least methanol, water, and oxygen are mixed. A raw material gas to be contained is prepared. Note that the oxygen-containing gas has a small heat capacity compared to methanol and water, and thus does not need to be heated, but may be heated if necessary.
　また、メタノール１モルあたりの酸素含有ガスに含まれている酸素ガスの量は、未反応のメタノールの残存量を低減させる観点から、好ましくは０．０５モル以上、より好ましくは０．０８モル以上であり、メタノールから生成した水素ガスと投入した酸素ガスとの反応によって反応温度が高くなることを回避するとともに、生成した水素ガスが酸素ガスとの反応によって消費されることを回避する観点から、好ましくは０．２０モル以下、より好ましくは０．１５モル以下である。 The amount of oxygen gas contained in the oxygen-containing gas per mole of methanol is preferably 0.05 moles or more, more preferably 0.08 moles or more, from the viewpoint of reducing the remaining amount of unreacted methanol. From the viewpoint of avoiding that the reaction temperature becomes high due to the reaction between the hydrogen gas generated from methanol and the introduced oxygen gas, and that the generated hydrogen gas is consumed by the reaction with oxygen gas, Preferably it is 0.20 mol or less, More preferably, it is 0.15 mol or less.
　酸素含有ガスは、第３バルブ１３が設けられた第３配管１１を介して反応ガス生成部２に向けて送気される。酸素含有ガスは、第３バルブ１３が開放された状態で、第３配管１１内を流れて、反応ガス生成部２に向けて送気される。 The oxygen-containing gas is sent toward the reaction gas generation unit 2 through the third pipe 11 provided with the third valve 13. The oxygen-containing gas flows through the third pipe 11 in a state where the third valve 13 is opened, and is sent toward the reaction gas generation unit 2.
　メタノール蒸気と水蒸気とを含有する混合ガスが流れる第２配管１０と、酸素含有ガスが流れる第３配管１１とは、第４配管１２に接続されており、この第４配管１２は、反応ガス生成部２に備えられる反応器２Ａに接続されている。第２配管１０内を流れる混合ガスと、第３配管１１内を流れる酸素含有ガスとは、第４配管１２内において混合され、これによって、少なくともメタノール、水および酸素を含有する原料ガスが調製される。このようにして調製された原料ガスは、第４配管１２内を流れて反応器２Ａに供給される。 A second pipe 10 through which a mixed gas containing methanol vapor and water vapor flows and a third pipe 11 through which an oxygen-containing gas flows are connected to a fourth pipe 12, and the fourth pipe 12 generates a reaction gas. It is connected to the reactor 2A provided in the section 2. The mixed gas flowing in the second pipe 10 and the oxygen-containing gas flowing in the third pipe 11 are mixed in the fourth pipe 12, thereby preparing a raw material gas containing at least methanol, water, and oxygen. The The raw material gas thus prepared flows through the fourth pipe 12 and is supplied to the reactor 2A.
　水素生成工程ｓ２は、第４配管１２内を流れて反応ガス生成部２の反応器２Ａに供給される原料ガスを、触媒の存在下で、メタノールの部分酸化反応および分解反応を進行させて、水素を含む反応ガスを生成する工程であり、反応ガス生成部２により実施される。本実施形態では、反応ガス生成部２は、保熱部４内に配設されている。このように反応ガス生成部２が保熱部４内に配設されることによって、保熱部４内に設置されているガス燃焼部９で残存ガスを燃焼することによって生じた熱により、吸熱を伴うメタノールの分解反応に起因する温度低下が抑制され、効率よく水素ガスを生成することができる。 In the hydrogen generation step s2, the raw material gas that flows in the fourth pipe 12 and is supplied to the reactor 2A of the reaction gas generation unit 2 is allowed to proceed in a partial oxidation reaction and decomposition reaction of methanol in the presence of a catalyst, This is a step of generating a reactive gas containing hydrogen, and is performed by the reactive gas generator 2. In the present embodiment, the reactive gas generation unit 2 is disposed in the heat retaining unit 4. By arranging the reaction gas generating unit 2 in the heat retaining unit 4 in this way, the heat generated by burning the residual gas in the gas burning unit 9 installed in the heat retaining unit 4 is absorbed. The temperature drop resulting from the decomposition reaction of methanol accompanied with the is suppressed, and hydrogen gas can be efficiently generated.
　第４配管１２を介して反応ガス生成部２に供給される原料ガスは、反応器２Ａに流入する前に、予め定める反応可能温度に調整される。原料ガスの温度は、反応器２Ａに流入する直前の温度（反応器２Ａの入口温度）が反応可能温度として調整される。反応器２Ａに流入する直前の、原料ガスの温度は、メタノールの部分酸化反応を促進させるとともに未反応のメタノールの残存量を低減させる観点から、好ましくは２００℃以上、より好ましくは２２０℃以上であり、触媒の耐熱温度の観点から、好ましくは３００℃以下、より好ましくは２６０℃以下である。 The raw material gas supplied to the reaction gas generation unit 2 via the fourth pipe 12 is adjusted to a predetermined reaction possible temperature before flowing into the reactor 2A. The temperature of the raw material gas is adjusted such that the temperature immediately before flowing into the reactor 2A (the inlet temperature of the reactor 2A) is the reaction possible temperature. The temperature of the raw material gas immediately before flowing into the reactor 2A is preferably 200 ° C. or higher, more preferably 220 ° C. or higher, from the viewpoint of promoting the partial oxidation reaction of methanol and reducing the remaining amount of unreacted methanol. In view of the heat resistant temperature of the catalyst, it is preferably 300 ° C. or lower, more preferably 260 ° C. or lower.
　反応器２Ａ内には、粒子状の触媒が充填されて触媒層が形成されている。触媒としては、酸化アルミニウムに銅系化合物が担持された触媒を挙げることができる。具体的には、酸化アルミニウムに銅が担持された触媒、酸化アルミニウムに銅および酸化亜鉛が担持された触媒が挙げられる。 In the reactor 2A, a particulate catalyst is filled to form a catalyst layer. Examples of the catalyst include a catalyst in which a copper compound is supported on aluminum oxide. Specific examples include a catalyst in which copper is supported on aluminum oxide and a catalyst in which copper and zinc oxide are supported on aluminum oxide.
　銅（Ｃｕ）と酸化アルミニウム（Ａｌ２Ｏ３）との質量比〔銅（Ｃｕ）／酸化アルミニウム（Ａｌ２Ｏ３）〕は、添加剤としての銅（Ｃｕ）の触媒活性が充分に発揮されるようにする観点から、０．１以上であることが好ましく、添加された銅（Ｃｕ）に充分な機械的強度を付与し、触媒活性を高くする観点から、１以下であることが好ましい。 The mass ratio of copper (Cu) to aluminum oxide (Al 2 O 3 ) [copper (Cu) / aluminum oxide (Al 2 O 3 )] exhibits sufficient catalytic activity of copper (Cu) as an additive. From the viewpoint of making it possible, it is preferably 0.1 or more, and from the viewpoint of imparting sufficient mechanical strength to the added copper (Cu) and increasing the catalytic activity, it is preferably 1 or less.
　市販されている酸化アルミニウムに銅が担持された触媒、または酸化アルミニウムに銅および酸化亜鉛が担持された触媒は、購入したときには、銅が酸化銅の状態で存在している。この状態では、触媒活性を示さないため、還元し銅にして使用することが好ましい。酸化銅を還元させる方法としては、たとえば、酸化銅を含む触媒を還元性ガスと接触させる方法などが挙げられるが、本発明は、かかる方法のみに限定されるものではない。還元性ガスとしては、たとえば、水素ガスをはじめ、水素ガスと窒素ガス、アルゴンガスなどの不活性ガスとの混合ガスなどが挙げられる。 A commercially available catalyst in which copper is supported on aluminum oxide or a catalyst in which copper and zinc oxide are supported on aluminum oxide is present in a state of copper oxide when purchased. In this state, since it does not show catalytic activity, it is preferable to use reduced copper. Examples of the method for reducing copper oxide include a method in which a catalyst containing copper oxide is brought into contact with a reducing gas, but the present invention is not limited to such a method. Examples of the reducing gas include hydrogen gas and a mixed gas of hydrogen gas and an inert gas such as nitrogen gas or argon gas.
　酸化アルミニウムに銅が担持された触媒、または酸化アルミニウムに銅および酸化亜鉛が担持された触媒の粒子径は、触媒層の圧力損失を低減させる観点から、好ましくは１ｍｍ以上、より好ましくは３ｍｍ以上であり、触媒と、メタノール蒸気、水蒸気および酸素含有ガスとの接触効率を高める観点から、好ましくは２０ｍｍ以下、より好ましくは１０ｍｍ以下である。また、酸化アルミニウムに銅が担持された触媒、または酸化アルミニウムに銅および酸化亜鉛が担持された触媒の充填量は、通常、原料ガス調製部１に送液されるメタノール１ｇ／分あたり３５ｍｌ以上であることが好ましい。 The particle diameter of the catalyst in which copper is supported on aluminum oxide or the catalyst in which copper and zinc oxide are supported on aluminum oxide is preferably 1 mm or more, more preferably 3 mm or more, from the viewpoint of reducing the pressure loss of the catalyst layer. From the viewpoint of increasing the contact efficiency between the catalyst and methanol vapor, water vapor and oxygen-containing gas, it is preferably 20 mm or less, more preferably 10 mm or less. The filling amount of the catalyst in which copper is supported on aluminum oxide or the catalyst in which copper and zinc oxide are supported on aluminum oxide is usually 35 ml or more per 1 g / min of methanol fed to the raw material gas preparation unit 1. Preferably there is.
　反応器２Ａは、断面形状が円形の筒状体であり、その筒状体の内部に触媒が充填されて柱状触媒層が形成されて構成される。また、反応器２Ａは、断面形状が円形の２つの筒状体が同心円状に重ね合わされ、それらの筒状体の間隙に触媒が充填されて筒状触媒層が形成されて構成されてもよい。すなわち、反応器２Ａは、円筒状に形成され、その内部空間に触媒が充填されている。また、反応器２Ａは、軸線方向一端部と他端部の内径が同じであり、この内径よりも軸線方向に延びる長さが長い形状である。 The reactor 2A is a cylindrical body having a circular cross-sectional shape, and a columnar catalyst layer is formed by filling the inside of the cylindrical body with a catalyst. Further, the reactor 2A may be configured such that two cylindrical bodies having a circular cross-sectional shape are concentrically overlapped, and a catalyst is filled in a gap between the cylindrical bodies to form a cylindrical catalyst layer. . That is, the reactor 2A is formed in a cylindrical shape, and its internal space is filled with a catalyst. The reactor 2A has the same inner diameter at one end in the axial direction and the other end, and has a shape extending longer in the axial direction than the inner diameter.
　また、触媒が充填されて触媒層が形成された反応器２Ａには、軸線方向一端から他端にわたって軸線に沿って延びる円筒状の保護管２Ｂが挿し込まれており、この保護管２Ｂには、触媒の表面温度を測定するための温度測定部材が挿入可能である。温度測定部材は、保護管２Ｂ内を、反応器２Ａの軸線に沿って移動可能である。これによって、反応器２Ａに充填される触媒の表面温度を、軸線方向一端から他端にわたる反応器２Ａ内の全領域で測定することができる。保護管２Ｂ内を移動する温度測定部材によって測定される温度は、反応器２Ａの外表面温度とは異なるものであり、反応器２Ａに充填される触媒表面の温度である。 Further, a cylindrical protective tube 2B extending along the axial line from one end to the other end in the axial direction is inserted into the reactor 2A in which the catalyst layer is formed by filling the catalyst, and this protective tube 2B is inserted into the protective tube 2B. A temperature measuring member for measuring the surface temperature of the catalyst can be inserted. The temperature measurement member can move in the protective tube 2B along the axis of the reactor 2A. Thereby, the surface temperature of the catalyst filled in the reactor 2A can be measured in the entire region in the reactor 2A extending from one end to the other end in the axial direction. The temperature measured by the temperature measuring member moving in the protective tube 2B is different from the outer surface temperature of the reactor 2A, and is the temperature of the catalyst surface charged in the reactor 2A.
　また、反応器２Ａには、触媒表面の温度を調整するための冷媒体または熱媒体を流すための流路となる冷熱媒体流通管２Ｃが設けられてもよい。なお、この冷熱媒体流通管２Ｃは、必ずしも設ける必要はない。 Further, the reactor 2A may be provided with a cooling medium circulation pipe 2C serving as a refrigerant body for adjusting the temperature of the catalyst surface or a flow path for flowing a heating medium. Note that the cooling medium circulation pipe 2C is not necessarily provided.
　さらにまた、反応器２Ａは、内部空間に形成される触媒層が、（有効面積（ｍ２）／軸線方向に延びる長さ（ｍ））が０．０１７以上０．０２５以下となるように形成されることが好ましい。ここで、有効面積とは、触媒層の、軸線に垂直な面の全面積から保護管２Ｂや冷熱媒体流通管２Ｃの面積を差し引いた面積のことである。 Furthermore, the reactor 2A is formed so that the catalyst layer formed in the internal space has an (effective area (m 2 ) / length extending in the axial direction (m)) of 0.017 or more and 0.025 or less. It is preferred that Here, the effective area is an area obtained by subtracting the area of the protective tube 2B or the cooling medium circulation tube 2C from the total area of the surface of the catalyst layer perpendicular to the axis.
　反応器２Ａ内に充填される触媒の表面温度（最高温度）は、メタノールを効率よく水素に改質させる観点から好ましくは２５０℃以上であり、触媒の劣化防止、反応副生成物の生成抑制、および、水素と酸素とが反応することを抑制する観点から、好ましくは３００℃以下である。また、反応器２Ａ内の圧力は、特に限定されないが、通常、ゲージ圧で０．２～１．５ＭＰａであることが好ましい。 The surface temperature (maximum temperature) of the catalyst charged in the reactor 2A is preferably 250 ° C. or more from the viewpoint of efficiently reforming methanol into hydrogen, preventing catalyst deterioration, and suppressing the production of reaction byproducts. And from a viewpoint which suppresses that hydrogen and oxygen react, Preferably it is 300 degrees C or less. Further, the pressure in the reactor 2A is not particularly limited, but it is usually preferable that the gauge pressure is 0.2 to 1.5 MPa.
　反応可能温度に調整された、少なくともメタノール、水および酸素を含有する原料ガスが第４配管１２を介して反応ガス生成部２に供給されると、その原料ガスは、反応器２Ａ内を軸線方向一端から他端に向けて、軸線に沿って流れる。このようにして原料ガスが反応器２Ａ内を流れて触媒と接触すると、メタノールが部分酸化されて水素と二酸化炭素が生成する、下記式（１）で表される部分酸化反応と、メタノールが一酸化炭素と水素に分解する、下記式（２）で表される分解反応と、メタノールが二酸化炭素と水素に分解する、下記式（３）で表される分解反応（水蒸気改質反応）とが進行する。
　　　ＣＨ３ＯＨ＋１／２Ｏ２→ＣＯ２＋２Ｈ２　　　　　　　　　　…（１）
　　　ＣＨ３ＯＨ→ＣＯ＋２Ｈ２　　　　　　　　　　　　　　　　　…（２）
　　　ＣＨ３ＯＨ＋Ｈ２Ｏ→ＣＯ２＋３Ｈ２　　　　　　　　　　　　…（３） When the raw material gas containing at least methanol, water and oxygen adjusted to the reaction possible temperature is supplied to the reactive gas generator 2 through the fourth pipe 12, the raw material gas passes through the reactor 2A in the axial direction. It flows along the axis from one end to the other end. When the raw material gas flows in the reactor 2A and contacts the catalyst in this way, methanol is partially oxidized to generate hydrogen and carbon dioxide, and the partial oxidation reaction represented by the following formula (1) is combined with methanol. A decomposition reaction represented by the following formula (2), which decomposes into carbon oxide and hydrogen, and a decomposition reaction (steam reforming reaction) represented by the following formula (3), in which methanol decomposes into carbon dioxide and hydrogen. proceed.
CH 3 OH + 1 / 2O 2 → CO 2 + 2H 2 (1)
CH 3 OH → CO + 2H 2 　　 ... (2)
CH 3 OH + H 2 O → CO 2 + 3H 2 (3)
　なお、式（１）で表される部分酸化反応は発熱反応であり、式（２），（３）で表される分解反応は吸熱反応である。 Note that the partial oxidation reaction represented by the formula (1) is an exothermic reaction, and the decomposition reactions represented by the formulas (2) and (3) are endothermic reactions.
　通常、原料ガスが流過する、触媒が充填された反応器２Ａにおいて、原料ガスの流れ方向上流側（軸線方向一端側）の部分で、反応速度の速い部分酸化反応が進行し、原料ガスの流れ方向下流側（軸線方向他端側）の部分で、反応速度の遅い分解反応が進行する。その結果、反応器２Ａにおける、原料ガスの流れ方向上流側の部分に存在する触媒が、発熱を伴う部分酸化反応の影響を受けて、３００℃を超える高温になる。３００℃を超える温度にまで加熱された触媒は、シンタリングが発生して劣化し、活性が低下して触媒寿命が短いものとなる。 Usually, in the reactor 2A filled with a catalyst through which the raw material gas flows, a partial oxidation reaction having a high reaction rate proceeds at a portion upstream of the raw material gas in the flow direction (one axial end side). A decomposition reaction with a slow reaction rate proceeds on the downstream side in the flow direction (the other end in the axial direction). As a result, the catalyst existing in the upstream portion of the reactor 2A in the flow direction of the raw material gas becomes high temperature exceeding 300 ° C. due to the influence of the partial oxidation reaction accompanied by heat generation. A catalyst heated to a temperature exceeding 300 ° C. is deteriorated due to sintering, resulting in a decrease in activity and a short catalyst life.
　さらに、酸化アルミニウムに銅系化合物が担持された触媒を用いた場合に、その触媒表面の温度が３００℃を超える高温になると、酸化アルミニウムがメタノール脱水触媒として機能し、下記式（４）で表されるジメチルエーテル生成反応が進行してしまう。
　　　２ＣＨ３ＯＨ→ＣＨ３ＯＣＨ３＋Ｈ２Ｏ　　　　　　　　　　　…（４） Further, when a catalyst in which a copper compound is supported on aluminum oxide is used, when the temperature of the catalyst surface exceeds 300 ° C., the aluminum oxide functions as a methanol dehydration catalyst and is expressed by the following formula (4). The dimethyl ether production reaction proceeds.
2CH 3 OH → CH 3 OCH 3 + H 2 O (4)
　式（４）で表されるジメチルエーテルの生成反応が進行すると、式（１）で表される部分酸化反応、および、式（２），（３）で表される分解反応による水素の生成量が減少するとともに、装置の不安定化を引き起こしてしまう。詳細については後述するが、反応ガスから高純度水素を分離した際の残部ガスをガス燃焼部９で燃焼させ、その燃焼によって発生する熱を原料ガス調製部１で利用するが、ジメチルエーテルの生成により燃焼熱量が異なってしまい、装置の不安定化が起こる。 When the formation reaction of dimethyl ether represented by formula (4) proceeds, the amount of hydrogen produced by the partial oxidation reaction represented by formula (1) and the decomposition reaction represented by formulas (2) and (3) As well as decreasing, it causes destabilization of the device. Although details will be described later, the remaining gas when high-purity hydrogen is separated from the reaction gas is burned in the gas combustion unit 9, and the heat generated by the combustion is used in the raw material gas preparation unit 1, but by the generation of dimethyl ether The amount of combustion heat differs, and the device becomes unstable.
　上記のような、触媒表面温度の高温化に伴う問題点を解決するために、本実施形態の水素の製造方法における水素生成工程ｓ２では、内部空間に形成される触媒層の（有効面積／軸線方向に延びる長さ）が０．０１７～０．０２５となるように設定された反応器２Ａにおいて、反応器２Ａ内を流れる原料ガスの流量を制御することによって、原料ガスが接触する触媒表面の最高温度を３００℃以下に制御する。より具体的には、水素生成工程ｓ２では、反応器２Ａ内を流れる原料ガスの線速度が０．０１～０．２（Ｎｍ／ｓ）となるように、反応器２Ａ内を流れる原料ガスの流量を制御する。さらに好ましくは、水素生成工程ｓ２では、反応器２Ａ内を流れる原料ガスの線速度が０．０１～０．２（Ｎｍ／ｓ）となり、かつ、原料ガスの空間速度が２００～１５００（／ｈ）となるように、反応器２Ａ内を流れる原料ガスの流量を制御する。 In order to solve the problems associated with the increase in the catalyst surface temperature as described above, in the hydrogen generation step s2 in the hydrogen production method of the present embodiment, the (effective area / axis line) of the catalyst layer formed in the internal space. In the reactor 2A set so that the length extending in the direction) is 0.017 to 0.025, the flow rate of the raw material gas flowing in the reactor 2A is controlled, so that the surface of the catalyst with which the raw material gas contacts is controlled. The maximum temperature is controlled to 300 ° C or lower. More specifically, in the hydrogen generation step s2, the raw material gas flowing in the reactor 2A is adjusted so that the linear velocity of the raw material gas flowing in the reactor 2A is 0.01 to 0.2 (Nm / s). Control the flow rate. More preferably, in the hydrogen generation step s2, the linear velocity of the raw material gas flowing in the reactor 2A is 0.01 to 0.2 (Nm / s), and the spatial velocity of the raw material gas is 200 to 1500 (/ h). ) To control the flow rate of the raw material gas flowing in the reactor 2A.
　反応器２Ａ内を流れる原料ガスの流量は、第１配管６を流れるメタノールおよび水の液流の流量、および、第３配管１１を流れる酸素含有ガスの流量を調整することによって制御することができる。 The flow rate of the raw material gas flowing through the reactor 2A can be controlled by adjusting the flow rate of the liquid flow of methanol and water flowing through the first pipe 6 and the flow rate of the oxygen-containing gas flowing through the third pipe 11. .
　本実施形態の水素の製造方法では、反応器２Ａ内を流れる原料ガスの流量を制御することによって部分酸化反応と分解反応との反応速度差を小さくし、原料ガスの流れ方向に関して反応器２Ａ内のほぼ同一部分で、部分酸化反応と分解反応とが進行する。その結果、発熱を伴う部分酸化反応で発生した熱が、吸熱を伴う分解反応で消費されるので、反応器２Ａ内に充填される触媒において、発熱を伴う部分酸化反応のみの影響を強く受けて、過度に温度上昇する部分が発生するのを抑制することができ、触媒表面の最高温度を３００℃以下に制御することができる。したがって、本実施形態の水素の製造方法によれば、触媒寿命を延ばすことができるとともに、水素を長期間にわたって安定して製造することができる。 In the hydrogen production method of the present embodiment, the reaction rate difference between the partial oxidation reaction and the decomposition reaction is reduced by controlling the flow rate of the raw material gas flowing in the reactor 2A, and the reaction gas in the reactor 2A has a flow direction. The partial oxidation reaction and the decomposition reaction proceed in substantially the same part of the above. As a result, the heat generated in the partial oxidation reaction with exotherm is consumed in the decomposition reaction with endotherm, so that the catalyst charged in the reactor 2A is strongly influenced only by the partial oxidation reaction with exotherm. Further, it is possible to suppress the occurrence of excessive temperature rise, and the maximum temperature of the catalyst surface can be controlled to 300 ° C. or lower. Therefore, according to the method for producing hydrogen of this embodiment, the catalyst life can be extended and hydrogen can be produced stably over a long period of time.
　さらに、本実施形態の水素の製造方法では、反応器２Ａ内を流れる原料ガスの流量が制御されて、触媒表面の最高温度が３００℃以下に制御されるので、酸化アルミニウムに銅系化合物が担持された触媒を用いても、メタノールからジメチルエーテルが生成する反応が進行するのを抑制することができ、その結果、水素の生成収率を高収率に維持することができる。 Furthermore, in the method for producing hydrogen according to the present embodiment, the flow rate of the raw material gas flowing in the reactor 2A is controlled, and the maximum temperature on the catalyst surface is controlled to 300 ° C. or lower, so that a copper compound is supported on aluminum oxide. Even when the prepared catalyst is used, it is possible to suppress the progress of the reaction for producing dimethyl ether from methanol, and as a result, the production yield of hydrogen can be maintained at a high yield.
　反応器２Ａにおいてメタノールの部分酸化反応および分解反応が進行して生成された反応ガスには、水素ガスの他に、未反応のメタノール蒸気、二酸化炭素ガス、一酸化炭素ガス、水蒸気、ジメチルエーテルなどの不純物ガスが含まれている。反応器２Ａで生成された反応ガスは、第５配管１４および第６配管１５を介して水素ガス分離部３に供給される。 The reaction gas generated by the partial oxidation reaction and decomposition reaction of methanol in the reactor 2A includes, in addition to hydrogen gas, unreacted methanol vapor, carbon dioxide gas, carbon monoxide gas, water vapor, dimethyl ether, etc. Impurity gas is included. The reaction gas generated in the reactor 2 </ b> A is supplied to the hydrogen gas separation unit 3 through the fifth pipe 14 and the sixth pipe 15.
　第５配管１４と第６配管１５との間には、熱交換器８が配設されている。この熱交換器８において、反応器２Ａで生成された反応ガスと、原料のメタノールおよび水とが熱交換することによって、当該メタノールおよび水を効率よく加熱することができ、反応ガスは、メタノールおよび水と熱交換することによって効率よく冷却することができる。 A heat exchanger 8 is disposed between the fifth pipe 14 and the sixth pipe 15. In this heat exchanger 8, the reaction gas generated in the reactor 2 </ b> A and the raw materials methanol and water can be subjected to heat exchange, whereby the methanol and water can be efficiently heated. It can cool efficiently by exchanging heat with water.
　水素ガス分離工程ｓ３は、第５配管１４および第６配管１５を介して水素ガス分離部３に供給される反応ガスから水素ガスを、不純物ガスと分離する工程であり、水素ガス分離部３により実施される。 The hydrogen gas separation step s3 is a step of separating hydrogen gas from the impurity gas from the reaction gas supplied to the hydrogen gas separation unit 3 through the fifth pipe 14 and the sixth pipe 15, and the hydrogen gas separation unit 3 To be implemented.
　水素ガス分離部３としては、たとえば、吸着剤が充填された吸着塔などが挙げられる。吸着塔は、１本のみを用いてもよいが、高純度の水素ガスを効率よく製造する観点から、たとえば、２～５本程度の複数本を用いることが好ましい。 Examples of the hydrogen gas separation unit 3 include an adsorption tower filled with an adsorbent. Although only one adsorption tower may be used, it is preferable to use a plurality of, for example, about 2 to 5 from the viewpoint of efficiently producing high-purity hydrogen gas.
　吸着剤としては、二酸化炭素、メタノール、ジメチルエーテルなどを除去する場合には、炭素系吸着剤などが挙げられ、一酸化炭素を除去する場合には、ゼオライトなどが挙げられ、また水蒸気などを除去する場合には、アルミナなどが挙げられる。通常、これらの吸着剤は、未反応メタノールの蒸気、二酸化炭素ガス、一酸化炭素ガス、水蒸気、ジメチルエーテルなどの不純物ガスを吸着することによって除去するために、混合して用いられる。 Examples of the adsorbent include carbon-based adsorbents when removing carbon dioxide, methanol, dimethyl ether, and the like, and zeolites and the like for removing carbon monoxide when removing carbon monoxide. In some cases, alumina or the like is used. Usually, these adsorbents are mixed and used for removing by adsorbing impurity gases such as vapor of unreacted methanol, carbon dioxide gas, carbon monoxide gas, water vapor, dimethyl ether and the like.
　水素ガスの分離は、圧力変動吸着装置（ＰＳＡ）にて行なう。より具体的には、たとえば、特開２００４－６６１２５号公報に記載の分離方法などに準じて行なうことができる。 Hydrogen gas is separated by a pressure fluctuation adsorption apparatus (PSA). More specifically, for example, the separation can be performed according to the separation method described in JP-A-2004-66125.
　水素ガス分離工程ｓ３で得られた高純度の水素ガスは、第７配管１６を介して水素ガス貯蔵用タンク１７に貯蔵されるが、たとえば、得られた高純度の水素ガスを現場で速やかに使用する場合には、水素ガス貯蔵用タンク１７は、必ずしも必要ではない。 The high-purity hydrogen gas obtained in the hydrogen gas separation step s3 is stored in the hydrogen gas storage tank 17 via the seventh pipe 16. For example, the obtained high-purity hydrogen gas can be promptly used on site. When used, the hydrogen gas storage tank 17 is not necessarily required.
　一方、水素ガス分離部３で吸着除去された不純物ガスは、たとえば、水素ガスの製造を停止した後、水素ガス分離部３内を脱気することにより、水素ガス分離部３内に残存している残存ガスとして回収することができる。残存ガスには、不純物ガスのほか水素ガスが含まれている。残存ガスは、第８配管１８を介して保熱部４内に配設されているガス燃焼部９に送気される。 On the other hand, the impurity gas adsorbed and removed by the hydrogen gas separation unit 3 remains in the hydrogen gas separation unit 3 by, for example, degassing the hydrogen gas separation unit 3 after the production of the hydrogen gas is stopped. It can be recovered as a residual gas. The residual gas contains hydrogen gas in addition to impurity gas. The residual gas is sent to the gas combustion unit 9 disposed in the heat retaining unit 4 through the eighth pipe 18.
　残存ガス燃焼工程ｓ４は、残存ガスを燃焼する工程であり、ガス燃焼部９により実施される。本実施形態では、残存ガスを廃棄ガスとして処分したり、燃焼したりするのではなく、前記したように、保熱部４内に配設されたガス燃焼部９で燃焼することによって残存ガスの有効利用を図る。 The residual gas combustion step s4 is a step of burning the residual gas, and is performed by the gas combustion unit 9. In the present embodiment, the residual gas is not disposed as waste gas or burned, but is burned in the gas combustion section 9 disposed in the heat retaining section 4 as described above, so that the residual gas is Make effective use.
　残存ガスを燃焼する際に発生する燃焼熱を利用してメタノールおよび水を加熱すれば、メタノール蒸気および水蒸気を効率よく製造することができる。また、同時に残存ガスの燃焼熱により、上記式（２），（３）で表される、吸熱を伴うメタノールの分解反応の際の熱を供給することができることから、効率よく水素ガスを生成させることができる。 If methanol and water are heated using combustion heat generated when the residual gas is burned, methanol vapor and water vapor can be produced efficiently. At the same time, heat from the decomposition reaction of methanol accompanied by endotherm represented by the above formulas (2) and (3) can be supplied by the combustion heat of the residual gas, so that hydrogen gas is efficiently generated. be able to.
　残存ガスを燃焼する際には、触媒を用いることが好ましい。触媒の中では、触媒活性が高く、耐熱性に優れていることから、白金触媒が好ましい。白金触媒は、ハニカム構造を有する担体に白金が担持されたものが好ましい。メタルハニカム、セラミックハニカムが用いられる。白金触媒は白金粒子であってもよく、アルミナ粒子などの担体に白金が担持されたものであってもよい。残存ガスを燃焼する際の触媒としては、前記白金の他に、パラジウム、ロジウム、銀などの貴金属やこれらの金属の化合物などが挙げられる。 It is preferable to use a catalyst when burning the residual gas. Among the catalysts, a platinum catalyst is preferable because of its high catalytic activity and excellent heat resistance. The platinum catalyst is preferably one in which platinum is supported on a carrier having a honeycomb structure. Metal honeycombs and ceramic honeycombs are used. The platinum catalyst may be platinum particles, or may be one in which platinum is supported on a carrier such as alumina particles. Examples of the catalyst for burning the residual gas include noble metals such as palladium, rhodium and silver, and compounds of these metals in addition to the platinum.
　残存ガスを燃焼する際には、残存ガスを燃焼させるために空気を用いることが好ましい。空気の量は、残存ガスに含まれている水素ガスが充分に燃焼する量であればよく、特に限定されない。残存ガスを燃焼する際に発生する燃焼熱による反応ガスであるメタノール蒸気および水蒸気の加熱温度は、未反応のメタノールの残存量を少なくして水素ガスの発生量を増大させる観点から、好ましくは２５０℃以上であり、触媒の劣化を抑制する観点から、好ましくは６００℃以下である。 When burning the residual gas, it is preferable to use air in order to burn the residual gas. The amount of air is not particularly limited as long as the hydrogen gas contained in the residual gas is sufficiently combusted. From the viewpoint of increasing the amount of hydrogen gas generated from the viewpoint of reducing the amount of unreacted methanol and increasing the amount of hydrogen gas generated, the heating temperature of methanol vapor and water vapor, which are reaction gases due to combustion heat generated when the residual gas is burned, is preferably 250. From the viewpoint of suppressing catalyst deterioration, it is preferably 600 ° C. or lower.
　次に、本発明を実施例に基づいてさらに詳細に説明するが、本発明は、かかる実施例のみに限定されるものではない。 Next, the present invention will be described in more detail based on examples. However, the present invention is not limited to such examples.
　（実施例１）
　軸線方向に延びる長さ１０００ｍｍ、内径１５４．４ｍｍで温度測定用の保護管が中央に設置された円筒状のＳＵＳ３０４製反応器内に、酸化アルミニウムに酸化銅および酸化亜鉛が担持された触媒（三菱ガス化学製、ＭＧＣ－ＭＨ１、粒径３ｍｍ）を充填した後、水素ガスを４ｖｏｌ％含む窒素ガスを約２１Ｎｍ３／ｈで約１０時間反応器内に導入することにより、酸化銅を還元させた。この反応器の（有効面積（ｍ２）／軸線方向に延びる長さ（ｍ））は０．０１９である。 (Example 1)
A catalyst in which copper oxide and zinc oxide are supported on aluminum oxide (Mitsubishi) in a cylindrical SUS304 reactor having a length of 1000 mm extending in the axial direction and an inner diameter of 154.4 mm and a temperature measuring protective tube installed in the center. After filling with Gas Chemical Co., MGC-MH1, particle size 3 mm), the copper oxide was reduced by introducing nitrogen gas containing 4 vol% of hydrogen gas into the reactor at about 21 Nm 3 / h for about 10 hours. . The reactor has an effective area (effective area (m 2 ) / length extending in the axial direction (m)) of 0.019.
　メタノールおよび水をそれぞれ２１８．５ｇ／分および１８４．７ｇ／分の流量で原料ガス調製部に送液し、その原料ガス調製部にて気化させて、メタノール蒸気と水蒸気を含む混合ガスを得た。この混合ガスと、標準状態（ＮＴＰ）で６８Ｌ／分の流量で流れる空気（酸素含有ガス）とを混合して原料ガスとし、その原料ガスを上記の反応器に導入した。なお、反応器に流入する直前の原料ガスの温度（反応器の入口温度）は、２４０℃に制御した。このとき、水／メタノールのモル比は１．５／１、酸素／メタノールのモル比は０．０９／１であった。また、原料ガスの線速度（ＬＶ）は０．２（Ｎｍ／ｓ）、空間速度（ＳＶ）は１２３０（／ｈ）であり、反応器内のゲージ圧を０．８ＭＰａに制御した。 Methanol and water were fed to the raw material gas preparation unit at flow rates of 218.5 g / min and 184.7 g / min, respectively, and vaporized in the raw material gas preparation unit to obtain a mixed gas containing methanol vapor and water vapor. . This mixed gas was mixed with air (oxygen-containing gas) flowing at a flow rate of 68 L / min in the standard state (NTP) to form a raw material gas, and the raw material gas was introduced into the reactor. The temperature of the raw material gas immediately before flowing into the reactor (reactor inlet temperature) was controlled at 240 ° C. At this time, the molar ratio of water / methanol was 1.5 / 1, and the molar ratio of oxygen / methanol was 0.09 / 1. The linear velocity (LV) of the raw material gas was 0.2 (Nm / s), the space velocity (SV) was 1230 (/ h), and the gauge pressure in the reactor was controlled to 0.8 MPa.
　（実施例２）
　原料ガスの線速度を０．０４（Ｎｍ／ｓ）、空間速度を２５０（／ｈ）にしたこと以外は、実施例１と同様にして反応を行なった。 (Example 2)
The reaction was performed in the same manner as in Example 1 except that the linear velocity of the source gas was 0.04 (Nm / s) and the space velocity was 250 (/ h).
　（比較例１）
　原料ガスの線速度を１．６（Ｎｍ／ｓ）、空間速度を１７００（／ｈ）にしたこと以外は、実施例１と同様にして反応を行なった。 (Comparative Example 1)
The reaction was performed in the same manner as in Example 1 except that the linear velocity of the source gas was 1.6 (Nm / s) and the space velocity was 1700 (/ h).
　（比較例２）
　原料ガスの線速度を０．４（Ｎｍ／ｓ）、空間速度を４２５（／ｈ）にしたこと以外は、実施例１と同様にして反応を行なった。 (Comparative Example 2)
The reaction was carried out in the same manner as in Example 1 except that the linear velocity of the source gas was 0.4 (Nm / s) and the space velocity was 425 (/ h).
　＜評価結果＞
　上記の実施例１，２および比較例１，２において、十分に装置を安定させるために、１回７時間運転を７回繰り返した後、反応器内に充填された触媒の表面温度の分布、未反応メタノール量および反応後のガス中の水素ガス量、ジメチルエーテル（ＤＭＥ）ガス量を調べた。反応後のガス中の水素ガス量、ＤＭＥガス量は、反応器からの排出される反応ガスをガスクロマトグラフィで分析することによって調べた。 <Evaluation results>
In Examples 1 and 2 and Comparative Examples 1 and 2 described above, in order to sufficiently stabilize the apparatus, after repeating the operation once for 7 hours 7 times, distribution of the surface temperature of the catalyst charged in the reactor, The amount of unreacted methanol, the amount of hydrogen gas in the gas after reaction, and the amount of dimethyl ether (DME) gas were examined. The amount of hydrogen gas and DME gas in the gas after the reaction was examined by analyzing the reaction gas discharged from the reactor by gas chromatography.
　評価結果を図４、図５、および表１に示す。図４は、反応器における原料ガス流れ方向上流側端部からの距離と、触媒表面温度との関係を示すグラフである。図５は、原料ガスの線速度と、反応器内における触媒表面の最高温度との関係を示すグラフである。 Evaluation results are shown in FIGS. 4 and 5 and Table 1. FIG. 4 is a graph showing the relationship between the distance from the upstream end portion in the raw material gas flow direction in the reactor and the catalyst surface temperature. FIG. 5 is a graph showing the relationship between the linear velocity of the raw material gas and the maximum temperature of the catalyst surface in the reactor.
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
　図４に示すように、反応器において、原料ガス流れ方向上流側端部からの距離が短い部分に存在する触媒は、発熱を伴うメタノールの部分酸化反応の影響を受けて高温になる。このような現象は、実施例１，２および比較例１，２のいずれにおいても発生しているが、触媒表面の最高温度には大きな違いがあった。具体的には、表１に示すように、実施例１における触媒表面の最高温度は２９３℃であり、実施例２における触媒表面の最高温度は２６２℃であった。このように、実施例１，２では、触媒表面の最高温度が３００℃以下であった。これに対して、比較例１における触媒表面の最高温度は３９１℃であり、比較例２における触媒表面の最高温度は３３１℃であり、比較例１，２では触媒表面の最高温度が３００℃を超える温度であった。 As shown in FIG. 4, in the reactor, the catalyst present in the portion having a short distance from the upstream end portion in the raw material gas flow direction becomes high temperature due to the influence of the partial oxidation reaction of methanol accompanied by heat generation. Such a phenomenon occurred in any of Examples 1 and 2 and Comparative Examples 1 and 2, but there was a great difference in the maximum temperature of the catalyst surface. Specifically, as shown in Table 1, the maximum temperature on the catalyst surface in Example 1 was 293 ° C., and the maximum temperature on the catalyst surface in Example 2 was 262 ° C. Thus, in Examples 1 and 2, the maximum temperature on the catalyst surface was 300 ° C. or lower. In contrast, the maximum temperature on the catalyst surface in Comparative Example 1 is 391 ° C., the maximum temperature on the catalyst surface in Comparative Example 2 is 331 ° C., and in Comparative Examples 1 and 2, the maximum temperature on the catalyst surface is 300 ° C. It was over temperature.
　このような触媒表面の温度は、原料ガスの反応器内における流量によって制御することができ、実施例１，２では、原料ガスの線速度が０．０１～０．２（Ｎｍ／ｓ）の範囲内であり、かつ、空間速度が２００～１５００（／ｈ）の範囲内となるように、反応器内に流れる原料ガスの流量を制御しているので、触媒表面の最高温度を３００℃以下に制御することができる。 The temperature of such a catalyst surface can be controlled by the flow rate of the raw material gas in the reactor. In Examples 1 and 2, the linear velocity of the raw material gas is 0.01 to 0.2 (Nm / s). Since the flow rate of the raw material gas flowing in the reactor is controlled so that the space velocity is in the range of 200 to 1500 (/ h) within the range, the maximum temperature on the catalyst surface is 300 ° C or less. Can be controlled.
　また、表１に示す結果から明らかなように、実施例１，２では、反応器に投入した原料メタノールを全て消費した上で、副生成物であるＤＭＥの発生を抑制した、水素ガスを含む反応ガスを製造することができることがわかる。また、実施例１，２では、触媒表面の最高温度が３００℃以下の低い状態であることから、触媒寿命を延ばすことができるとともに、水素を長期間にわたって安定して製造することができることが見込まれる。 Further, as is clear from the results shown in Table 1, Examples 1 and 2 contain hydrogen gas that suppresses the generation of DME as a by-product after consuming all of the raw material methanol charged into the reactor. It can be seen that the reaction gas can be produced. In Examples 1 and 2, since the maximum temperature on the catalyst surface is a low state of 300 ° C. or lower, it is expected that the catalyst life can be extended and hydrogen can be produced stably over a long period of time. It is.
　これに対して、比較例１，２では、反応器に投入した原料メタノールを全て消費しているが、反応温度の上昇にともない副生成物であるジメチルエーテルが増加していることがわかる。また、比較例１，２では、触媒表面の最高温度が３００℃を超える高温状態であることから、触媒寿命が短くなるおそれがある。 On the other hand, in Comparative Examples 1 and 2, all of the raw material methanol charged into the reactor was consumed, but it can be seen that by-product dimethyl ether increased as the reaction temperature increased. In Comparative Examples 1 and 2, since the maximum temperature on the catalyst surface is in a high temperature state exceeding 300 ° C., the catalyst life may be shortened.
　［反応器内に流入する直前の、原料ガス温度の影響］
　反応器内に流入する直前の、原料ガス温度の影響を確認するために、上記の実施例２を基準として、以下に示す実施例３，４を検討した。 [Influence of raw material gas temperature just before flowing into the reactor]
In order to confirm the influence of the raw material gas temperature immediately before flowing into the reactor, Examples 3 and 4 shown below were examined on the basis of Example 2 described above.
　（実施例３）
　反応器に流入する直前の原料ガスの温度を２２０℃に制御したこと以外は、実施例２と同様にして反応を行なった。 (Example 3)
The reaction was carried out in the same manner as in Example 2 except that the temperature of the raw material gas immediately before flowing into the reactor was controlled at 220 ° C.
　（実施例４）
　反応器に流入する直前の原料ガスの温度を２６０℃に制御したこと以外は、実施例２と同様にして反応を行なった。 Example 4
The reaction was carried out in the same manner as in Example 2 except that the temperature of the raw material gas immediately before flowing into the reactor was controlled at 260 ° C.
　＜評価結果＞
　上記の実施例２～４において、十分に装置を安定させるために、１回７時間運転を７回繰り返した後、反応器内に充填された触媒表面の最高温度を評価した。評価結果を図６および表２に示す。図６は、反応器内に流入する直前の原料ガスの温度と、反応器内における触媒表面の最高温度との関係を示すグラフである。 <Evaluation results>
In Examples 2 to 4 described above, in order to sufficiently stabilize the apparatus, the operation was repeated once for 7 hours 7 times, and then the maximum temperature of the catalyst surface charged in the reactor was evaluated. The evaluation results are shown in FIG. FIG. 6 is a graph showing the relationship between the temperature of the raw material gas immediately before flowing into the reactor and the maximum temperature of the catalyst surface in the reactor.
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000002
　図６および表２に示す結果から明らかなように、反応器内に流入する直前の原料ガスの温度を２２０～２６０℃の範囲内に制御することによって、反応器に充填される触媒表面の最高温度を３００℃以下に制御することができることがわかる。 As is apparent from the results shown in FIG. 6 and Table 2, the maximum temperature of the catalyst surface charged in the reactor is controlled by controlling the temperature of the raw material gas immediately before flowing into the reactor within the range of 220 to 260 ° C. It can be seen that the temperature can be controlled to 300 ° C. or lower.
　本発明は、その精神または主要な特徴から逸脱することなく、他のいろいろな形態で実施できる。したがって、前述の実施形態はあらゆる点で単なる例示に過ぎず、本発明の範囲は請求の範囲に示すものであって、明細書本文には何ら拘束されない。さらに、請求の範囲に属する変形や変更は全て本発明の範囲内のものである。 The present invention can be implemented in various other forms without departing from the spirit or main features thereof. Therefore, the above-described embodiment is merely an example in all points, and the scope of the present invention is shown in the scope of claims, and is not restricted by the text of the specification. Further, all modifications and changes belonging to the claims are within the scope of the present invention.
　１　原料ガス調製部
　２　反応ガス生成部
　３　水素ガス分離部
　４　保熱部
　９　ガス燃焼部 DESCRIPTION OF SYMBOLS 1 Raw material gas preparation part 2 Reaction gas production | generation part 3 Hydrogen gas separation part 4 Heat insulation part 9 Gas combustion part

Claims (4)

  1. 　メタノール、水および酸素を含む原料ガスを、予め定める反応可能温度に調整する温度調整工程と、
    　前記反応可能温度に調整された原料ガスを、粒子状の触媒が充填された反応器内に流過させて触媒と接触させることによって、メタノールの部分酸化反応および分解反応を進行させて、水素を生成する水素生成工程と、を含み、
    　前記水素生成工程では、反応器内を流過する原料ガスの流量を制御することによって、メタノールの部分酸化反応および分解反応の進行中における、原料ガスが接触する触媒表面の最高温度を３００℃以下に制御することを特徴とする水素の製造方法。     A temperature adjustment step of adjusting a raw material gas containing methanol, water and oxygen to a predetermined reactionable temperature;
    The raw material gas adjusted to the reaction possible temperature is caused to flow through a reactor filled with a particulate catalyst and brought into contact with the catalyst, thereby causing the partial oxidation reaction and decomposition reaction of methanol to proceed, thereby allowing hydrogen to flow. A hydrogen production step to produce,
    In the hydrogen generation step, by controlling the flow rate of the raw material gas flowing through the reactor, the maximum temperature of the catalyst surface in contact with the raw material gas during the partial oxidation reaction and decomposition reaction of methanol is 300 ° C. or less. A method for producing hydrogen, characterized in that the control is carried out.
  2. 　前記水素生成工程では、反応器内を流過する原料ガスの線速度が０．０１～０．２（Ｎｍ／ｓ）となるように、原料ガスの流量を制御することを特徴とする請求項１に記載の水素の製造方法。 The flow rate of the raw material gas is controlled so that the linear velocity of the raw material gas flowing through the reactor becomes 0.01 to 0.2 (Nm / s) in the hydrogen generation step. 2. The method for producing hydrogen according to 1.
  3. 　前記水素生成工程では、反応器内を流過する原料ガスの空間速度が２００～１５００（／ｈ）となるように、原料ガスの流量を制御することを特徴とする請求項２に記載の水素の製造方法。 3. The hydrogen gas according to claim 2, wherein in the hydrogen generation step, the flow rate of the raw material gas is controlled so that the space velocity of the raw material gas flowing through the reactor becomes 200 to 1500 (/ h). Manufacturing method.
  4. 　前記触媒は、酸化アルミニウムに銅系化合物が担持された触媒であることを特徴とする請求項１～３のいずれか１つに記載の水素の製造方法。 The method for producing hydrogen according to any one of claims 1 to 3, wherein the catalyst is a catalyst in which a copper compound is supported on aluminum oxide.
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JP2003112902A (en) * 2001-10-01 2003-04-18 Nissan Motor Co Ltd Apparatus for controlling fuel reformer
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