JP2005281343A - Method for producing high-pressure hydrogen - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a new technique for selectively taking out hydrogen under high pressure from hydrogen-containing high-pressure fuel gas obtained by hydrothermal reaction from a liquid organic substance. <P>SOLUTION: The method for producing high-pressure hydrogen comprises (1) a first process for producing hydrogen-containing fuel gas by the hydrothermal reaction of a liquid organic substance in subcritical water or supercritical water using a catalyst and (2) a second process for removing impurities containing carbon monoxide, carbon dioxide gas and methane derived from the hydrothermal reaction from the fuel gas obtained by the first process under high pressure. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method for producing hydrogen-containing fuel gas using a liquid organic material as a starting material, and further producing high-pressure and high-purity hydrogen by removing impurities.

  In the present invention, the “liquid organic substance” generally means “a liquid mixture in which a liquid and / or solid organic substance is dissolved or dispersed in water”. Such a liquid organic material is not particularly limited, but in addition to various organic materials provided as industrial raw materials and fuels, liquid or water-containing organic waste such as domestic wastewater, industrial wastewater, sludge, etc. And a mixture obtained by appropriately mixing and pulverizing solid organic matter such as waste wood, paper, and plastics and organic waste liquid, or those obtained by biologically, physically, and chemically treating these.

  Conventionally, solid organic waste (aerobic sludge, anaerobic sludge, sludge such as sewage sludge; straw, paper, plastic, wood pieces, bamboo pieces, grass pieces, straw, fibers, vegetable pieces, rubber, leather, Food processing waste, livestock waste, forest thinning / fallen tree, pruning waste, agriculture and forestry waste, marine product waste, etc.) and liquid organic waste (living wastewater, wastewater from food processing plants, livestock / Wastewater from poultry farms, industrial wastewater containing components that are difficult to biologically treat; wastewater containing alcohols, carboxylic acids, aldehydes, etc.) Has been processed.

  However, it is necessary to reuse these wastes as resources from the viewpoint of “effective use of limited resources”, which is a major technical issue now.

  As a result of conducting extensive research in view of the current state of such technology, the present inventors have made a hydrothermal reaction of liquid organic matter prepared from solid and liquid organic waste with high gasification efficiency. In addition, technologies for recovering and reusing fuel gas, electric power, thermal energy and the like in useful forms have been developed (Patent Documents 1 and 2).

  Non-Patent Document 1 reports a method for producing fuel gas under supercritical conditions at 600 ° C.

  Although this technique is extremely useful, the fuel gas produced contains high concentrations of methane and / or carbon monoxide. Therefore, in applications that require fuel gas containing hydrogen gas at a high concentration, such as stationary fuel cells, fuel cell vehicles, hydrogenation reactions, and ammonia production, the fuel gas cannot be used as it is. Further gas purification was required.

In addition, hydrogen is usually stored in a high-pressure hydrogen tank or the like in consideration of transportation or the like. However, when hydrogen is produced in a low-pressure state, it is necessary to make high-pressure hydrogen again with a compressor or the like, which is uneconomical. Therefore, it is very advantageous if high pressure hydrogen can be obtained by maintaining a high pressure derived from the hydrothermal reaction section in the production of hydrogen.
JP 2002-105466 A JP 2002-105467 A Xu, X., Matsumura, Y., Stenberg, J., Antal, M., Ind. Eng. Chem. Res., 35, 2522

  The main object of the present invention is to provide a new technique capable of selectively extracting hydrogen under high pressure from a high-pressure fuel gas containing hydrogen obtained from a liquid organic substance by a hydrothermal reaction.

  The present inventor has found that the above-described problems can be achieved as a result of research on a technique for treating a liquid organic substance in view of the current state of the art as described above.

That is, the present invention provides the following method for producing high-pressure hydrogen using a liquid organic material as a raw material. (1) a first step of producing a fuel gas containing hydrogen by hydrothermal reaction of a liquid organic substance using a catalyst in subcritical water or supercritical water; and (2) from the fuel gas obtained in the first step. A method for producing high-pressure hydrogen, comprising a second step of removing impurities under high pressure derived from the hydrothermal reaction.

  Item 2. Item 1 is a process in which a liquid organic substance is hydrothermally reacted in subcritical water or supercritical water with a catalyst and sulfur or a sulfur compound to produce a fuel gas containing hydrogen. A method for producing high-pressure hydrogen described in 1.

  Item 3. In the second step, impurities are removed from the fuel gas obtained in the first step using an absorbing solution, or using a catalyst and an absorbing solution that promote a shift reaction from carbon monoxide to oxygen dioxide. Item 3. The method for producing high-pressure hydrogen according to Item 1 or 2, wherein the hydrogen is removed.

  Item 4. Item 4. The method for producing high-pressure hydrogen according to Item 3, wherein the second step further removes impurities using an adsorbent.

  The present invention is described in detail below.

The high-pressure hydrogen production method of the present invention includes (1) a first step of producing a fuel gas containing hydrogen by hydrothermal reaction of a liquid organic substance in subcritical water or supercritical water, and (2) the first step. From the obtained fuel gas, impurities are removed under high pressure derived from the hydrothermal reaction, and hydrogen is selectively extracted. High-pressure hydrogen can be easily produced by this production method.

The liquid organic substance to be treated by the present invention includes all liquid substances in which at least one of liquid and solid organic substances is dissolved or dispersed in a liquid such as water.

  Solid organic matter is not particularly limited, but is a general waste such as municipal waste; aerobic treated sludge, anaerobic treated sludge, sewage sludge, etc .; vegetation, bamboo, grass, straw, fibers, vegetable waste , Rubber, leather, solid organic matter such as biological waste and products such as agriculture / forestry / livestock / poultry / fisheries (corn shaft, okara, coffee beans, straw, rice straw, thinned wood, Fallen trees, etc .; biomass in a broad sense including giant kelp, eucalyptus, etc.); mineral products (coal, peat, etc.), various hydrocarbons and the like. These solid organic substances may be processed in a mixed state of two or more.

  Liquid organic sources include industrial raw materials such as methanol and various organic materials provided as fuel, domestic wastewater including firewood, paper, plastics, organic compounds (alcohols, ethers, carboxylic acids, aldehydes, etc. ) Wastewater, human waste, plating wastewater, food factory wastewater, paper mill wastewater, pharmaceutical factory wastewater, photographic wastewater, printing wastewater, agricultural chemical-related wastewater, dyeing wastewater, semiconductor manufacturing factory wastewater, coal liquefaction or gasification Examples include waste water and waste water containing organic substances such as waste water generated by thermal decomposition of municipal waste. These waste waters can be treated by mixing two or more kinds.

  The above-mentioned solid and liquid organic substance sources include one or more metal components such as Mg, Al, Si, P, Ca, Ti, Cr, Mn, Fe, Co, Ni, Cu, Zn, and Cd. May be included. The method of the present invention can be carried out even if the object to be processed contains such a metal component.

  The liquid organic material to be treated by the present invention can be formed by adding a liquid such as water, if necessary, to at least one of the above solid and liquid organic sources and stirring. At this time, the solid organic material source is preferably pulverized to an appropriate size in advance in order to form a slurry.

  Hereinafter, the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a flow sheet showing an outline of one embodiment of the method of the present invention.

  In the present invention, solid organic matter such as waste and biomass is fractionated by a pretreatment device (not shown) according to a conventional method in order to remove inorganic components such as metal and glass as much as possible, and then a crusher Etc. and then mixed with water and / or a liquid organic material source to form a liquid organic material.

First Step In the first step, a liquid organic substance is hydrothermally reacted in subcritical water or supercritical water to produce a fuel gas containing hydrogen.

  As shown in FIG. 1, in this invention, the liquid organic substance formed as mentioned above is processed. That is, the liquid organic substance is heated by the heat exchanger 2 through the liquid booster pump 1 and, if necessary, further heated to a temperature of 200 ° C. or higher by the heater 3, and then the hydrothermal reactor 4 filled with the catalyst. To be supplied. Any heating means can be used as the heat source of the heat exchanger 2. For example, as shown in FIG. 1, the gas-liquid mixed phase at the outlet of the hydrothermal reactor 4 can be used as a heat source.

  The reaction in the hydrothermal reactor is performed under supercritical to subcritical conditions in the presence of a catalyst. Here, the supercritical condition means, for example, a state in which water has a critical temperature of 374 ° C. or higher and a critical pressure of 22.1 MPa or higher (that is, a critical point or higher), and the subcritical condition is a temperature lower than the supercritical condition. It means about 200 ℃ or more and pressure of about 5MPa or more.

The temperature and pressure in the hydrothermal reaction are appropriately determined according to the type of catalyst, the composition of the liquid organic material to be treated, etc., but the temperature is usually about 300 to 500 ° C. (preferably about 420 to 480 ° C.), pressure May be about 20 to 50 MPa (preferably about 32 to 38 MPa). In particular, the object of the present invention is achieved without the temperature exceeding 500 ° C. The WHSV (= liquid organic matter amount [kg / h] ÷ catalyst weight [kg]) is about 0.5 to 120 h ⁻¹ (preferably about ¹ to 60 h ⁻¹ ), liquid linear velocity (inserted liquid amount / reaction tower The cross-sectional area (reactor inlet reference) may be within a range of 0.001 to 5 cm / sec (preferably about 0.01 to 1 cm / sec).

  In the present invention, since a catalyst is used, the hydrothermal reaction is promoted and the decomposition rate of the organic component in the liquid organic substance is improved. Therefore, under certain hydrothermal reaction conditions, the hydrothermal reactor can be downsized and / or the reaction time can be shortened. Alternatively, when using a hydrothermal reactor of the same volume, the reaction time can be shortened and / or mild reaction conditions can be employed.

  In general, mild reaction conditions using a catalyst (temperature of about 300 to 500 ° C) are regions where methane is likely to be generated thermodynamically, and the mechanical constraints for manufacturing a hydrothermal reactor are relaxed. However, it was disadvantageous for producing a fuel gas mainly composed of hydrogen.

  As the catalyst charged in the hydrothermal reactor 4, a catalyst in which a catalytically active component is supported on a carrier is preferably used. The catalytically active component is at least one selected from the group consisting of Ru, Pd, Rh, Pt, Au, Ir, Os, Fe, Cu, Zn, Ni, Co, Mn and Ce and water-insoluble or poorly water-soluble compounds thereof. The carrier includes at least one metal oxide selected from the group consisting of titania, zirconia, titania-zirconia, alumina, silica, alumina-silica, and activated carbon. Preferred metal active components include Ru, Pt and Ni, with Ru being particularly preferred. Preferred carriers include titania and activated carbon, with titania being particularly preferred.

  The amount of the catalytically active component supported on the carrier is usually about 0.01 to 10% by weight, more preferably about 0.1 to 3% by weight.

  As a method of supporting a metal which is a catalytically active component on a support, a known method is adopted, and for example, impregnation, alkali treatment, reduction and the like can be performed in combination.

  The shape of the catalyst is not particularly limited, and examples thereof include a spherical shape, a pellet shape, a columnar shape, a crushed piece shape, a powder shape, and a honeycomb shape.

  Alternatively, in the present invention, the production of methane and carbon monoxide is suppressed as much as possible by performing a hydrothermal reaction in the presence of a catalyst and sulfur or a sulfur compound (or in the presence of a catalyst containing sulfur or a sulfur compound). It is also possible to produce a fuel gas mainly composed of hydrogen. That is, a hydrothermal reaction can be performed by filling the catalyst and sulfur or a sulfur compound in the hydrothermal reactor 4 of FIG.

  Although it will not specifically limit as a sulfur compound if it is a compound which contains a sulfur atom widely, An inorganic sulfur compound is illustrated preferably. For example, sulfate, sulfite, thiosulfate, disulfate, disulfite, dithionate, dithionate, trithionate, peroxomonosulfate, tetrathionate, peroxodisulfate, polythionate And inorganic sulfur compounds such as sulfide salts. These salts should just be salts, such as an alkali metal, alkaline-earth metal, and ammonium, for example. Examples of the alkali metal include lithium, sodium, and potassium, and examples of the alkaline earth metal include beryllium, magnesium, calcium, and barium.

  Of these sulfur compounds, preferably, alkali metal sulfates, sulfites, thiosulfates or sulfide salts, alkaline earth metal sulfates, sulfites, thiosulfates or sulfide salts, sulfur, etc. Is mentioned. More preferred are alkali metal sulfates or alkaline earth metal sulfates, particularly sodium sulfate, potassium sulfate, barium sulfate and magnesium sulfate.

  Sulfur has various allotropes, but any allotrope may be used.

  The form using the catalyst and sulfur or sulfur compound is not particularly limited as long as the catalyst and sulfur or sulfur compound are both present in the hydrothermal reactor and the hydrothermal reaction is performed.

  For example, as a first embodiment, a hydrothermal reaction is performed using a catalyst obtained by treating a catalyst in which an active component is supported on the above-described carrier (not containing a sulfur compound) with sulfur or a sulfur compound. Specifically, after the catalyst in which the active component is supported on the carrier is filled in the hydrothermal reactor 4, an aqueous medium containing sulfur or a sulfur compound is passed through the hydrothermal reactor 4 to perform the initial operation. Contacting sulfur or sulfur compounds with the catalyst. The aqueous medium containing sulfur or a sulfur compound may be prepared by adjusting the content of sulfur or sulfur compound so that the sulfur concentration in the aqueous medium is about 1 to 30 mg / L. In addition to water, other organic substances (alcohols, liquid organic substances to be treated, etc.) may be included. In the initial operation, the above-described hydrothermal reaction conditions are employed, and it may be usually about 20 to 60 hours.

  Moreover, as a 2nd form, the catalyst by which the active component was carry | supported beforehand by the support | carrier containing sulfur or a sulfur compound can be used. This catalyst can be produced by adding or mixing sulfur or a sulfur compound to the carrier in the production process of the carrier. Such a catalyst containing sulfur or a sulfur compound on the carrier can be produced, for example, by mixing sulfur or a sulfur compound with powder of the carrier main component, molding, drying, and firing. The content of sulfur or sulfur compound in the catalyst is not particularly limited, but the content of sulfur or sulfur compound in the support is usually about 0.01 to 5% by weight, preferably about 0.1 to 1% by weight. is there.

  The catalyst containing sulfur or a sulfur compound produced as described above is used as it is for a hydrothermal reaction of a liquid organic substance.

  Thus, according to the hydrothermal reaction of the present invention using a catalyst and sulfur or a sulfur compound, a hydrogen-rich fuel gas with as little content of methane and carbon monoxide as possible can be produced. In general, the sulfur component has the possibility of reducing the catalytic activity due to catalyst poisoning, but in the present invention, the fuel gas having the above composition can be produced by positively adding this sulfur or sulfur compound to the catalyst. It has a surprising effect.

The reactor type of the hydrothermal reactor 4 is not particularly limited, but a fixed bed is exemplified. In the case of a fixed bed, the volume of the hydrothermal reactor 4 is such that the liquid space velocity (inlet reference) is about 0.5 to 100 hr ⁻¹ , more preferably about ¹ to 60 hr ⁻¹ . The size of the supported catalyst used in the fixed bed is usually about 1 to 20 mm, more preferably about 5 to 15 mm in the case of a spherical shape, a pellet shape, a cylindrical shape, a crushed piece shape, a powder shape and the like.

  The gas-liquid mixed phase formed in the hydrothermal reactor 4 is taken out of the reactor and is primarily cooled in the cooler 5 through the heat exchanger 2. Furthermore, it is sent to the gas-liquid separator 6 through a pressure reducing valve as necessary, and separated into a gas phase (fuel gas) and a liquid phase (exhaust water). The obtained gas phase is taken out of the system through a pressure holding valve (not shown), and the liquid phase is taken out of the system through a liquid level adjusting valve (not shown).

  Fuel gas produced by hydrothermal reaction using a catalyst usually depends on the reaction temperature, but usually 10-40 vol% hydrogen, 20-65 vol% methane, 20-30 vol% carbon dioxide About 0 to 30 vol% of carbon monoxide. The fuel gas produced using the catalyst and sulfur or sulfur compound is about 70 to 76 vol% hydrogen, about 1.5 vol% or less (particularly 1.2 vol% or less) methane, and about 22 to 28 vol% carbon dioxide. , And about 1.5 vol% or less of carbon monoxide, resulting in a relatively high hydrogen content.

  The energy generated in the hydrothermal reaction can be recovered in the form of heat, electric power or the like by any known method at any stage of the gas-liquid mixed phase, the gas phase, and the liquid phase.

Second Step In the second step, impurities including carbon monoxide, carbon dioxide, methane and the like are removed from the fuel gas obtained in the first step using an absorbing liquid (high pressure water). Alternatively, impurities including carbon monoxide, carbon dioxide, methane, and the like are removed using a catalyst that promotes a shift reaction from carbon monoxide to oxygen dioxide and an absorbing liquid (high-pressure water).

  After the high-pressure fuel gas obtained in the first step is gas-liquid separated by the gas-liquid separator 6, the gas on the gas phase side is brought into contact with the absorbing liquid in the absorption tower 7, and carbon monoxide, carbon dioxide gas and methane in the gas Impurities containing oxygen are transferred to the absorption liquid side. Here, water can be used as the absorbing liquid. Note that the gas-liquid separator 6 may be omitted when water is used as the absorbing liquid and the organic matter is completely gasified during the hydrothermal reaction and the fluid after the reaction is considered to be water and gas.

  Most of the gas phase gas other than hydrogen is carbon dioxide, and the solubility of carbon dioxide in water is higher than that of hydrogen. In the second step, since the operation is performed at a higher pressure, the solubility of carbon dioxide in water increases as the pressure increases, so that efficient carbon dioxide removal from the high-pressure gas becomes possible.

  Water used as the absorbing liquid is useful because it is a safe and inexpensive material. However, the absorption liquid is not necessarily limited to water, and a chemical absorption method of carbon dioxide using an aqueous solution containing a basic substance (eg, amine, potassium carbonate, sodium carbonate) or the like according to a conventional method is used. It is also possible.

  The absorption tower 7 is preferably filled with a filler, and is not particularly limited as long as it is a filler that promotes gas-liquid contact such as Raschig ring.

  Furthermore, the absorption tower 7 can be filled with a catalyst that shifts carbon monoxide to carbon dioxide. Thereby, carbon monoxide in the high-pressure gas can be converted to carbon dioxide, and the obtained carbon dioxide can be efficiently absorbed and removed by the absorbent. That is, since a large amount of water is supplied as an absorbing solution in the adsorption tower 7, the thermodynamic equilibrium of the water-gas shift reaction of carbon monoxide moves to the carbon dioxide side. Conversion is facilitated, and carbon monoxide is efficiently removed by conversion to a form of carbon dioxide that is readily soluble in water.

  Examples of these water gas shift catalysts include iron oxide, chromium oxide, copper oxide, and zinc oxide. The usage-amount of a catalyst can be suitably selected according to reaction conditions. The form of the catalyst is not particularly limited, and a known form can be adopted.

The gas-liquid ratio of the absorbing liquid (for example, water) and the high-pressure fuel gas in the absorption tower 7 is usually about 10 to 100 kg, preferably about 15 to 45 kg of water with respect to 1 m ^{3 of} fuel gas. If it is. Within this range, carbon dioxide can be efficiently absorbed and removed from the high-pressure gas.

  The pressure in the absorption tower 7 is maintained at a high pressure derived from the hydrothermal reaction in the first step, and is, for example, about 10 to 50 MPa, preferably about 30 to 40 MPa. The temperature in the absorption tower 7 is usually about 10 to 100 ° C., preferably about 10 to 40 ° C. when only the absorbing liquid is brought into contact with the high pressure fuel gas, and the water gas shift catalyst is used for the high pressure fuel gas. When the absorbing solution is brought into contact with the catalyst, the temperature is usually about 100 to 300 ° C., preferably about 120 to 200 ° C., in order to obtain the activation temperature of the catalyst.

  The absorption liquid in which impurity components such as carbon dioxide are dissolved is reduced in pressure by the pressure reducing valve 10 and then sent to the deaerator 9 to release the dissolved gas components as off-gas. The absorption liquid after releasing the dissolved gas can be recycled to the absorption tower 7 again.

  According to the above method, a high-pressure fuel gas having a hydrogen concentration of approximately 90 vol% or more, particularly 95 vol% or more can be produced. However, when further purity is required, the obtained high-pressure fuel gas is adsorbed to the adsorption tower. Send to 8. The adsorption tower 8 is filled with an adsorbent such as zeolite and carbon molecular sieve, for example, so that impurity components such as carbon dioxide gas and methane other than hydrogen can be adsorbed and removed. The form of the adsorbent in the adsorption tower 8 is not particularly limited, and a known one is adopted.

  In general, the amount of adsorption per unit weight of the adsorbent increases as the operating pressure increases, so that the present invention using high-pressure gas enables more efficient adsorption and removal of impurities. The pressure in the adsorption tower 8 is about 10 to 50 MPa, preferably about 30 to 40 MPa, and the temperature may be about 10 to 40 ° C.

  Although a high-pressure fuel gas purification method using only adsorption is possible in principle, most of the impurities including carbon dioxide are removed by combining with the absorption method using the above-mentioned absorption liquid, so that the burden of the adsorbent is reduced. Has the advantage that the life of the adsorbent can be extended.

  The fuel gas that has passed through the adsorption tower 8 is high-purity hydrogen having a hydrogen concentration of 99.9 vol% or more, more than 99.99 vol%, especially 99.999 vol%, and the hydrogen gas pressure is about 10 to 50 MPa, preferably 30-40 MPa.

  As described above, according to the method of the present invention, high-pressure and high-purity hydrogen can be produced. Therefore, by adopting a storage method using pressure such as a cylinder, the fuel gas in a form suitable for transportation is used. Recovery is possible. In addition, it can be easily supplied to a system that needs to store hydrogen at a high density (concentration) such as a fuel cell vehicle.

  According to the method of the present invention, high-pressure and high-purity hydrogen can be efficiently produced. Therefore, by adopting a storage method using pressure such as a cylinder, it is possible to recover the fuel gas in a form suitable for transportation. In addition, it can be easily supplied to a system that needs to store hydrogen at a high density (concentration) such as a fuel cell vehicle. Moreover, when organic waste is used as a raw material, it can be efficiently converted into high-pressure hydrogen, which contributes to effective use of resources.

  Next, the present invention will be described in more detail by way of examples, but is not limited thereto.

Example 1
(1) In accordance with the flow shown in FIG. 1, according to the present invention, fuel gas was produced using alcohol water as a raw material. As alcohol water, water containing 10 wt% of methanol was used.

  The raw material was pressurized to a pressure of 35 MPa by the liquid booster pump 1 and introduced into the heat exchanger 2 under pressure. In the heat exchanger 2, the temperature of the raw material was raised by exchanging heat with the fluid flowing out of the reactor 4, and the temperature was raised by the heater 3 to 450 ° C. This raw material was introduced into the reactor 4 to perform a gasification (hydrothermal) reaction.

The reactor 4 is packed with a spherical catalyst (2 to 3 mm in diameter) in which 2 wt% of ruthenium supported on a titania support containing barium sulfate of 0.4 wt% of the support weight is supported, The gasification reaction was performed under the conditions of a temperature of 450 ° C., a pressure of 35 MPa, WHSV (= methanol water flow rate (kg / h) ÷ catalyst weight (kg)) of 10 h ⁻¹ , and a liquidus velocity of 0.05 cm / s. Since the gasification reaction is an endothermic reaction, heating was performed to maintain the reaction temperature.

The fluid produced in the reactor was cooled by the heat exchanger 2 and further by the cooler 5 and then separated into fuel gas and discharged water by the gas-liquid separator 6. The composition of the fuel gas obtained at this time was 71.6 vol% hydrogen, 1.1 vol% methane, 26.4 vol% carbon dioxide, 0.9 vol% carbon monoxide, and the pressure was 35 MPa.
(2) This gas was sent to the absorption tower 7 and brought into contact with water as an absorption liquid whose pressure was increased by a separate pump (not shown). The amount of water at this time was 30 kg with respect to 1 m ^{3 of} fuel gas. The absorption tower 7 was filled with an iron oxide catalyst as a catalyst for converting carbon monoxide into carbon dioxide. At this time, the gas composition at the outlet of the absorption tower 7 was hydrogen 91.2 vol%, methane 1.4 vol%, carbon monoxide 0.6 vol%, carbon dioxide 6.8 vol%, and the pressure was 35 MPa.

  This gas was further sent to an adsorption tower 9 filled with a carbon molecular sieve and zeolite at a volume ratio of 1: 4. Hydrogen gas with a hydrogen purity of 99.999 vol% was obtained from the outlet of the adsorption tower 9 and the pressure was 35 MPa.

Example 2
The fuel gas obtained in the same manner as in Example 1 (1) (composition: hydrogen 71.6 vol%, methane 1.1 vol%, carbon dioxide 26.4 vol%, carbon monoxide 0.9 vol%) was sent to the absorption tower 7 and pumped separately. It was made to contact with water as an absorption liquid pressurized by (not shown). The absorption tower 7 was filled with Raschig rings without any catalyst. The amount of water at this time was 30 kg per 1 m ³ of fuel gas. At this time, the gas composition at the outlet of the absorption tower 7 was hydrogen 90.7 vol%, methane 1.4 vol%, carbon monoxide 1.2 vol%, carbon dioxide 6.7 vol%, and the pressure was 35 MPa.

  This gas was further sent to an adsorption tower 8 packed with a carbon molecular sieve and zeolite at a volume ratio of 1: 4. Hydrogen gas with a hydrogen purity of 99.999 vol% was obtained from the outlet of the adsorption tower, and the pressure was 35 MPa.

It is a flow sheet which shows the outline of the manufacturing method of high pressure hydrogen of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Liquid pressurization pump 2 Heat exchanger 3 Heater 4 Reactor 5 Cooler 6 Gas-liquid separator 7 Absorption tower 8 Adsorption tower 9 Deaerator 10 Pressure reducing valve

Claims (4)

(1) a first step of producing a fuel gas containing hydrogen by hydrothermal reaction of a liquid organic substance using a catalyst in subcritical water or supercritical water; and (2) from the fuel gas obtained in the first step. A method for producing high-pressure hydrogen, comprising a second step of removing impurities under high pressure derived from the hydrothermal reaction. The first step is a step of producing a fuel gas containing hydrogen by hydrothermally reacting a liquid organic material in subcritical water or supercritical water with a catalyst and sulfur or a sulfur compound. 2. The method for producing high-pressure hydrogen according to 1. In the second step, impurities are removed from the fuel gas obtained in the first step using an absorbing solution, or using a catalyst and an absorbing solution that promote a shift reaction from carbon monoxide to oxygen dioxide. The method for producing high-pressure hydrogen according to claim 1 or 2, wherein the hydrogen is removed. The method for producing high-pressure hydrogen according to claim 3, wherein the second step further removes impurities using an adsorbent.

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