JP2005216774A - Hydrogen supplying device of fuel cell for working machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hydrogen supplying device of fuel cell for a working machine with high storing capacity from which, hydrogen contained in hydrogenated aromatic compound as raw material can be stably taken out without using a very high pressure resistant container nor a thermally insulated container containing cryogenic liquid. <P>SOLUTION: The hydrogen supplying device, mounted on a working machine together with a fuel cell, supplying refined hydrogen to the fuel cell comprises a raw fuel tank storing hydrogenated aromatic compound in a state of liquid at normal temperature and normal pressure; a dehydrogenation reactor in which dehydrogenation catalyst, having a hydrogenated aromatic compound inversion rate of 90% or higher at relatively low dehydrogenation reaction temperature of approximately 300°C, is filled, generating aromatic compound and hydrogen through the dehydrogenation reaction of the hydrogenated aromatic compound; a gas-liquid separator separating liquid component mainly composed of aromatic compound and gaseous component mainly composed of hydrogen generated at the dehydrogenation reactor; and a hydrogen refining device in which an adsorbent is filled, adsorbing and removing the impure gas excluding hydrogen from the gaseous component separated at the gas-liquid separator. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to vehicles such as automobiles and railways, airplanes such as airplanes and rockets, ships such as ships and submarines, large commercial or small stationary fuel cell power supplies for home use, or such business. Used together with the fuel cell to supply purified hydrogen to the above-mentioned fuel cell in various operating housings such as household generators and vending machines equipped with large or household small stationary fuel cell power supplies The present invention relates to a hydrogen supply device mounted on an operating housing.

In recent years, the development of fuel cells that use electricity and heat generated when hydrogen and oxygen react to become water has been developed as an effective energy source, which discharges harmful substances that replace vehicle engines and household generators. It is expected as a power source that does not.
However, the supply of hydrogen, which is the fuel for such fuel cells, is difficult to handle because it is a gas that is difficult to condense and has a tendency to explode. A system that directly supplies hydrogen is not necessarily established, and the use of compressed hydrogen (35 to 75 MPa), liquefied hydrogen (-253 ° C), hydrogen storage alloys, hydrogenated aromatics (chemical hydrides), etc. is still under consideration [Catalyst, Vol. 43, No. 4, 259-263 (2001); OHM, Vol. 89, No. 3, 29-36 (2002)].

However, the use of compressed hydrogen requires an ultra-high pressure pressure vessel that reaches 70 MPa, and the use of liquefied hydrogen requires a heat-insulating vessel that contains an ultra-low temperature liquid of -253 ° C. The use of storage alloys has problems such as relatively low hydrogen storage density and complicated heat management for hydrogen adsorption / desorption.
In contrast, the use of hydrogenated aromatics is considered to be the only way to meet the target values of the US Department of Energy (DOE) and Japan's hydrogen utilization development program because of its extremely high hydrogen storage density. However, a dehydrogenation catalyst that can stably extract hydrogen in a high yield has not been developed so far, and has not been realized.

  In particular, the dehydrogenation reaction of hydrogenated aromatics is an equilibrium reaction and requires a high reaction temperature of about 300 ° C. or higher in order to obtain a high equilibrium conversion rate, and a simple fixed bed packed with a conventional catalyst. When a reactor is used, a high reaction temperature exceeding 500 ° C. is required, so the deterioration of the catalyst due to coking is a problem, and it is possible to produce it with stationary equipment that requires regeneration equipment and the like. However, it was thought that it was difficult to mount it directly on an operating housing such as a fuel cell vehicle.

The research group of Prof. Yasukazu Saito of Tokyo Rika University uses a liquid film state between the liquid phase and the gas phase called the superheated liquid film method in the reaction field to solve the problem of heat source and catalyst degradation. Proposed a method for dehydrogenation at a low temperature of about 200 ° C. by evading equilibrium regulation (Yasukazu Saito, Surface, Vol. 33, No. 1, 1-9 (1995)).

Japanese Patent Laid-Open No. 2002-134,141 discloses a system for producing hydrogen by this method. For example, a hydrogen storage body containing a liquid organic hydrogen storage body such as toluene and a liquid organic material such as methylcyclohexane. A hydrogen supply container containing a hydrogen supply (hydrogenated aromatics) and a reaction vessel having a metal-supported catalyst for performing a hydrogenation reaction of a liquid organic hydrogen storage body and a dehydrogenation reaction of a liquid organic hydrogen supply body And a supply means for supplying the liquid organic hydrogen storage body or the liquid organic hydrogen supply body to the reaction container from the hydrogen storage body storage section or the hydrogen supply body storage section when necessary, and hydrogen produced in the reaction container is separated And a hydrogen storage / supply system for storing or supplying hydrogen using a hydrogenation reaction of a liquid organic hydrogen storage body using a metal-supported catalyst and a dehydrogenation reaction of a liquid organic hydrogen supply body. Beam has been proposed.

  In addition, in Catalyst, Vol.43, No.4, 259-263 (2001), when boiling and heating an appropriate amount of decalin on a carbon-supported metal catalyst, naphthalene and hydrogen are rapidly generated, and a high conversion rate is obtained. It is described that heat utilization can be achieved.

The method of using this superheated liquid film state as a reaction field is a very efficient method. However, a reactor for maintaining the reaction field in an actual reactor, its control method, and a compact reactor Therefore, development of a hydrogen supply system mounted on an operating chassis with a highly active dehydrogenation catalyst that can be used at a relatively low temperature in a simple fixed bed reactor has been desired.
JP 2002-134,141 A Catalyst, Vol.43, No.4, 259-263 (2001) OHM, Vol.89, No.3, 29-36 (2002) Yasukazu Saito, Surface, Vol.33, No.1, 1-9 (1995)

  In view of this, the present inventors have developed a dehydrogenation catalyst that can stably extract hydrogen in a high yield in the dehydrogenation reaction of hydrogenated aromatics, and can supply hydrogen to an operating chassis such as a fuel cell vehicle. As a result of diligent investigations on establishing a hydrogen supply system for an operating chassis to be supplied, we developed a dehydrogenation catalyst with a dehydrogenation reaction temperature of about 300 ° C and a conversion rate of hydrogenated aromatics of 90% or more. A fixed bed dehydrogenation reactor filled with this, and a hydrogen purifier that adsorbs and removes impurity gas other than hydrogen from the hydrogen-based gas component produced in the dehydrogenation reactor filled with an adsorbent. By using it, it was found that a hydrogen supply system to various operating frames could be established, and the present invention was completed.

  Therefore, an object of the present invention is to use hydrogenated aromatics as a hydrogen storage medium, and does not require the use of an ultra-high pressure pressure vessel or a heat-insulated vessel containing ultra-low temperature liquid, and can also manage complicated heat. It is an object of the present invention to provide a hydrogen supply device for a fuel cell for an operating chassis that can be used for a fuel cell for an operating chassis that can stably extract hydrogen in a high yield without need.

  That is, the present invention is a hydrogen supply device for a fuel cell for an operating chassis that is mounted on an operating chassis together with a fuel cell and supplies purified hydrogen to the fuel cell, and is loaded with liquid hydrogenated aromatics at room temperature and normal pressure And a dehydrogenation catalyst having a conversion temperature of hydrogenated aromatics of 90% or more at a reaction temperature of 300 ° C. for the dehydrogenation reaction and corresponding aromatics by dehydrogenation of the hydrogenated aromatics. A dehydrogenation reactor that produces hydrogen and hydrogen, a gas-liquid separator that separates an aromatic-based liquid component and a hydrogen-based gas component produced in the dehydrogenation reactor, and an adsorbent A hydrogen supply device for a fuel cell for an operating enclosure, comprising: a hydrogen purifier that adsorbs and removes an impurity gas other than hydrogen from the gas component separated by the gas-liquid separator.

  The hydrogenated aromatics to be dehydrogenated by the dehydrogenation catalyst of the present invention are not particularly limited as long as they are stable and dehydrogenated to become stable aromatics. Preferably monocyclic hydrogenated aromatics such as cyclohexane, methylcyclohexane and dimethylcyclohexane, bicyclic hydrogenated aromatics such as tetralin, decalin and methyldecalin, and tricyclic hydrogenated such as tetradecahydroanthracene Aromatics can be mentioned, and more preferred are monocyclic hydrogenated aromatics such as cyclohexane, methylcyclohexane and dimethylcyclohexane, and bicyclic hydrogenated aromatics such as tetralin, decalin and methyldecalin. .

  In the hydrogen supply apparatus according to the present invention, it is necessary to mount a storage tank for the hydrogenated aromatic compound that is a raw material for the dehydrogenation reaction in the hydrogen storage medium and the dehydrogenated product to be recovered. At this time, when there is room in the device, it is a simple method to mount two tanks, but it was consumed by using a tank with a movable partition plate in one tank. It is conceivable to use it as a storage space for the dehydrogenated product obtained by collecting the space for the raw material. Regarding the mixing of the dehydrogenated product into the hydrogenated product, there is no particular danger due to the mixing, and it is sufficient if the dehydrogenated product can be blocked to the extent that the loss of the raw material does not become excessive. By adopting such a tank, it is possible to substantially reduce the volume of the raw material tank to the volume of the raw material.

  The dehydrogenation catalyst used in the present invention has a conversion rate of hydrogenated aromatics as a hydrogen storage medium of 90% or more, preferably 95% or more at a reaction temperature of 300 ° C. in the dehydrogenation reaction. In the hydrogen generation capacity, it has a performance of 900 Ncc / h / cc-cat or more, more preferably 1,000 Ncc / h / cc-cat or more. By using a simple fixed bed reactor filled with this dehydrogenation catalyst, hydrogen can be generated at a relatively low reaction temperature of 250 to 350 ° C. and in a high yield. The target hydrogen loading amount of 5 kg of hydrogen can be generated in about 5 hours using about 12 liters (L) of catalyst.

  As such a dehydrogenation catalyst, preferably, a porous γ-alumina carrier having specific physical properties, one or more kinds of catalyst metals selected from platinum, palladium, ruthenium, rhodium and iridium are used. , Lithium, sodium, potassium, rubidium, cesium, beryllium, magnesium, calcium, strontium and barium supported by one or more alkaline metals selected from groups 1A and 2A of the periodic table Particularly preferably, platinum as a catalyst metal is in the range of 0.3% by weight to 2.0% by weight, preferably 0.5% by weight to 1.0% by weight, Further, potassium as an alkaline metal is supported in the range of 0.001% to 1.0% by weight, preferably 0.005% to 0.5% by weight. The is a catalyst.

The porous γ-alumina support constituting the dehydrogenation catalyst preferably has a surface area of 150 m ² / g or more, a pore volume of 0.55 cm ³ / g or more, an average pore diameter of 90 to 300 mm, and The occupation ratio of the pore diameter of 90 to 300 mm should be 60% or more, and if the surface area is less than 150 m ² / g, the activity after catalysis is not sufficient, and the pore volume is less than 0.55 cm ³ / g. If the average pore diameter is smaller than 90 mm, the surface area is increased, but the pore volume is decreased. Conversely, if the average pore diameter is larger than 300 mm, the surface area is decreased. Since the pore volume becomes large, an average pore diameter of 90 to 300 mm is appropriate as a result of comprehensively considering these correlations. Further, when the occupation ratio of 90 to 300 mm pores is less than 60%, the effect of the present invention is reduced in catalyst performance.

  Such a porous γ-alumina carrier having specific physical properties is obtained by filtering and washing a slurry of aluminum hydroxide produced by neutralization of an aluminum salt, as disclosed in, for example, Japanese Patent Publication No. 6-72,005. The obtained alumina hydrogel is dehydrated and dried and then calcined at 400 to 800 ° C. for about 1 to 6 hours. Preferably, the pH value of the alumina hydrogel is adjusted to the alumina hydrogel dissolution pH region and the boehmite gel precipitation. It is obtained through a pH swing process in which an alumina hydrogel-forming substance is added to grow an alumina hydrogel crystal when the pH is changed between at least one of the pH ranges and from one pH range to the other. It is good to be. The porous γ-alumina support obtained through this pH swing process is excellent in the uniformity of pore distribution, there is little variation in physical properties even in the alumina support pellets after molding, and the physical properties of each pellet are stable. It is excellent in that it is.

  For a dehydrogenation reactor filled with the above dehydrogenation catalyst and generating the corresponding aromatics and hydrogen by dehydrogenation of hydrogenated aromatics, the catalyst is housed and required for the reaction temperature and dehydrogenation reaction. What is necessary is just to give the endothermic amount. For example, a metal tube wrapped with an electric heater is sufficient as the simplest reactor, and the required amount of catalyst is divided into a plurality of tubes and packed in consideration of the heat transfer rate that gives the endothermic amount. A simple device such as a module is considered sufficient. Moreover, since it is a normal pressure reaction, strength against pressure is not required, and since mechanical strength is sufficient, the thickness of the reactor can be reduced and the weight can be reduced. Furthermore, since no corrosive fluid exists, it is not necessary to employ a particularly high-grade corrosion resistant material.

  In addition, when supplying hydrogenated aromatics stored in a liquid state at room temperature to a dehydrogenation reactor, it is considered necessary to have a preheater that raises the temperature to the reaction temperature. In this case, it is considered that the heat radiation becomes large and is not efficient. Therefore, it is preferable to provide an inert solid packing layer such as ceramic in the previous stage of the catalyst layer in the same reactor. As such an inert solid packing, α-alumina spheres, metallic packings, and the like are generally used, but these can be applied as they are in the present invention.

  In the present invention, the dehydrogenation reaction conditions in the dehydrogenation reactor are a reaction temperature of 250 ° C. or more and 350 ° C. or less, preferably 290 ° C. or more and 350 ° C. or less, and pass through the reaction region of this dehydrogenation reactor. The liquid space velocity (LHSV) of hydrogenated aromatics is 1.0 or more and 5.0 or less, preferably 2.0 or more and 4.0 or less. If this reaction temperature is lower than 250 ° C., there is a problem that the equilibrium conversion rate is low depending on the type of hydrogenated aromatic and a sufficient conversion rate cannot be obtained. Conversely, if the reaction temperature is higher than 350 ° C., the conversion rate is close to 100%. However, there is a problem that the degradation rate of the catalyst is increased at the same time as the selectivity is lowered due to an increase in decomposition products. In addition, the liquid space velocity (LHSV) has a problem that the required amount of catalyst increases and the volume of the reactor increases when the liquid space velocity (LHSV) is lower than 1.0. The problem that it cannot be obtained arises.

  In the present invention, gas-liquid separators for separating the liquid component mainly composed of aromatics and the gas component mainly composed of hydrogen from the reaction product generated in the dehydrogenation reactor may have various shapes. However, it may be a general one. For example, it is conceivable that the simplest shape is a coil type tube having a sufficient tube diameter, which is installed vertically and cooled to a possible temperature by air cooling. The removed heat can be used for heating the inside of the vehicle.

  Further, for the adsorbent for adsorbing and removing the impurity gas present in the vapor component other than hydrogen from the gas component used in the present invention, impurities other than hydrogen by-produced in the dehydrogenation reaction of the hydrogenated aromatics. Any gas can be used as long as it can be adsorbed and removed as much as possible. Specifically, for example, zeolite, silica, silica alumina, activated carbon and the like can be exemplified, preferably from the viewpoint of mechanical strength and adsorption capacity. Are zeolite, silica and silica alumina.

  The hydrogen purifier filled with such an adsorbent is only required to be able to efficiently bring the gas component produced by the dehydrogenation reaction into contact with the adsorbent. A type of adsorption column can be exemplified. In the hydrogen supply apparatus according to the present invention, since the selectivity of the dehydrogenation catalyst is as high as 98% or more, the gas generated from the dehydrogenation reactor already has a high hydrogen purity. Therefore, it is not necessary to employ a large-scale adsorption process, and high-purity hydrogen gas can be supplied simply by adsorbing and removing the liquid product corresponding to the vapor pressure.

At this time, when a compound having a side chain such as a methyl group is used as the hydrogenated aromatic, a gas such as methane generated by a slight decomposition reaction is generated. Straight chain alkanes such as methane are difficult to adsorb and remove and are supplied as they are to the fuel cell together with hydrogen. However, since they are inert gases and are in very small amounts, there is no problem in the fuel cell system.

  In other words, this hydrogen purifier preferably has a plurality of adsorption regions and switching means for switching and using the plurality of adsorption regions, and has not been used before the adsorption region in use is saturated by the switching means. It is preferable that the adsorption region can be switched to a used adsorption region, and the plurality of adsorption regions may be formed by dividing a single hydrogen purifier into a plurality of hydrogen purifiers. It may be configured.

  And about the adsorbent of the hydrogen purifier which adsorbed impurity gas other than hydrogen from gaseous components, Preferably heating temperature of the boiling range of hydrogenated aromatics 80 degreeC or more and 250 degrees C or less, Preferably it is 100 degrees C or more and 150 degrees C or less By adopting in combination with the above-mentioned multiple adsorption areas and switching means, it is possible to regenerate the adsorption area after use without stopping the operation enclosure. Operation becomes possible.

  Furthermore, when the hydrogenated aromatics are, for example, methylcyclohexane, the recovered gas component desorbed and recovered from the adsorption region in the regeneration process has a composition of 99.5% of the total of unreacted methylcyclohexane and produced toluene. As described above, since the decomposition product benzene is 0.5% or less, it is preferably condensed and returned to the raw material tank. However, in some cases, it can be combusted and discarded.

  In addition, a part or all of the thermal energy necessary for the dehydrogenation reactor and / or the regeneration treatment may be covered by an electric heater operated using a part of the electric power generated by the fuel cell. The dehydrogenation reactor may be kept warm by an appropriate warming means.

  The hydrogen supply device for mounting the fuel cell operating housing of the present invention uses hydrogenated aromatics having a very high hydrogen storage density as a raw material, and uses such an ultra-high pressure pressure vessel or a heat-insulated vessel containing ultra-low temperature liquid. In addition, hydrogen can be stably extracted in high yield from hydrogenated aromatics using a simple fixed bed reactor without requiring complicated heat management.

  Hereinafter, preferred embodiments of the hydrogen supply apparatus of the present invention will be described in detail with reference to the flowcharts shown in the accompanying drawings.

〔Example〕
FIG. 1 shows a system concept of a hydrogen supply device for a fuel cell for a working casing according to an embodiment of the present invention using methylcyclohexane (MCH) as a hydrogenated aromatic.

  As shown in FIG. 1, this hydrogen supply device basically corresponds to an MCH tank 1 that stores MCH as a hydrogen generation raw material and a dehydrogenation catalyst that will be described later and is filled with a dehydrogenation reaction of MCH. A dehydrogenation reactor 3 for producing toluene and hydrogen, a gas-liquid separator 5 for separating a toluene-based liquid component and a hydrogen-based gas component produced in the dehydrogenation reactor 3, and zeolite as an adsorbent And a hydrogen purifier 6 that adsorbs and removes an impurity gas having a vapor pressure other than hydrogen from the gas component separated by the gas-liquid separator 5.

  Further, as described above, in the case of a raw material tank provided with a movable partition plate, an MCH tank and a toluene tank can be used together, but they are described separately here for easy understanding. Further, the raw material preheater is described as an integrated reactor provided in the preceding stage of the catalyst layer in the reactor as described above.

In this embodiment, an MCH tank 1 for storing MCH, which is a hydrogen production raw material,
It is composed of a lightweight metal container, and is connected to the raw material inlet 3 a of the dehydrogenation reactor 3 through the liquid feed pump 2. The dehydrogenation reactor 3 is composed of a preheating layer filled with ceramic balls or the like and a catalyst layer following the preheating layer, and a preheating layer and a dehydrogenation catalyst filled in the dehydrogenation reactor 3 are provided on the peripheral wall thereof. A reactor heater 4 for heating the bed is provided, and this reactor heater 4 is heated by electric power supplied from a fuel cell FC driven by hydrogen generated in the dehydrogenation reactor 3. It is like that.

  The gas-liquid separator 5 for separating the toluene-based liquid component and the hydrogen-based gas component in the reaction product generated by the dehydrogenation reaction in the dehydrogenation reactor 3 is composed of a lightweight metal tube coil or the like. Then, it is connected to the product outlet 3 b of the dehydrogenation reactor 3, its gas component outlet 5 a is connected to the hydrogen purifier 6, and the liquid component 5 b is connected to the toluene tank 11.

  Further, in this embodiment, the hydrogen purifier 6 is composed of a pair of adsorption vessels 6a and 6b that are filled with zeolite as an adsorbent to form two adsorption regions, and the gas component inlet side of these adsorption vessels 6a and 6b. The adsorbing vessel 6a, 6b is switched to switch the gas component into which the gas component is introduced, for example, an introduction switching means 12 comprising an electromagnetic valve, and the adsorbing vessel 6a, 6b is provided on the purified hydrogen outlet side of the fuel cell FC. For example, an extraction valve 13a, 13b consisting of an electromagnetic valve for switching the connection to the combustor 14 side before the exhaust gas 15 and the toluene tank 11 side. Are provided with regeneration heaters 10a and 10b on the peripheral walls for heating and regenerating the adsorption regions in the adsorption containers 6a and 6b.

The purge gas necessary for regeneration may be the gas at the gas component outlet 5a from the gas-liquid separator 5 as it is, and it is heated above the boiling point of the dehydrogenated product corresponding to the hydrogenated aromatic used in the regeneration. If so, the amount is about 1 to 3 times the volume of the adsorption vessel, and most of the adsorbed components are removed, which is sufficient. The purged gas is sent to the gas-liquid separator 9. The gas-liquid separator 9 is composed of a light metal tube coil or the like, similar to the gas-liquid separator 5, and is connected to the extraction switching means 13a, 13b. The gas component outlet 9a is connected to the gas-liquid separator. The liquid component 9b is connected to the toluene tank 11 while being connected to the gas component outlet 5a.
The regeneration heaters 10a and 10b for the adsorption vessels 6a and 6b are also heated by the electric power supplied from the fuel cell FC driven by hydrogen generated in the dehydrogenation reactor 3, in the same manner as the reactor heater 4 described above. It has come to be.

  In the hydrogen purifier 6 of this embodiment, when the introduction switching means 12 selects, for example, one adsorption container 6a, the gas component introduction port side of the other adsorption container 6b is closed, and one of the adsorption containers 6b is closed. The take-out switching means 13a provided at the purified hydrogen outlet side of the adsorption vessel 6a opens the fuel cell FC side and closes the remaining toluene tank 11 side and the combustor 14 side, and the purified hydrogen removal of the other adsorption vessel 6b. The take-out switching means 13b provided on the outlet side closes the fuel cell FC side, the toluene tank 11 side is opened and the combustor 14 side is closed during the regeneration process of the adsorption region, and conversely, after the regeneration process of the adsorption region, the toluene tank 11 The side is closed and the combustor 14 side is opened.

  In this embodiment, the purified hydrogen outlet side of the hydrogen purifier 6 is connected to the fuel cell FC via the hydrogen compression pump 7 and the buffer tank 8, and the hydrogen produced in the dehydrogenation reactor 3 is separated into gas and liquid. The purified hydrogen is converted into purified hydrogen by the vessel 5 and the hydrogen purifier 6 and then temporarily stored in the buffer tank 8 and supplied to the fuel cell FC as necessary.

  The hydrogen supply apparatus of the present invention includes an MCH tank 1, a toluene tank 11, a liquid feed pump 2, a dehydrogenation reactor 3, gas-liquid separators 5 and 9, a hydrogen purifier 6, a hydrogen compression pump 7, and a buffer tank. Starting from the main equipment such as 8, etc., peripheral equipment such as the reactor heater 4, the regenerative heaters 10a and 10b, the combustor 14, and the control system such as the introduction switching means 12 and the extraction switching means 13a and 13b, Furthermore, the main devices, peripheral devices, power supplied to the control system, and the like are all controlled and managed by a control system (not shown).

(Preparation of alumina support)
A γ-alumina support was produced as described in Example 1 of JP-B-6-72,005. The outline of this method is as follows. Aqueous sodium aluminate aqueous solution is added instantaneously with vigorous stirring in hot dilute sulfuric acid to obtain an aluminum hydroxide slurry suspension (pH 10), which is used as seed aluminum hydroxide and stirred. The operation of adding hot dilute sulfuric acid and sodium aluminate aqueous solution alternately for a certain time while repeating the above is repeated to obtain a filter washed cake, which is extruded and dried, and then baked at 500 ° C. for 3 hours. . The properties of γ-alumina thus obtained are typically as shown in Table 1 below.

(Preparation of dehydrogenation catalyst)
Prepared as described above, surface area 240 m ² / g, pore volume 0.713 cm ³ / g, average pore diameter 119 mm, and the proportion of pore diameter 90 to 300 mm relative to the total pore volume (pore diameter To 20 g of a porous γ-alumina support having a physical property of 90% (occupancy ratio of 90 to 300 mm), 79 g of 0.4 wt% -chloroplatinic acid aqueous solution prepared so as to have a pH value of 2.0 was added, After impregnation by leaving for 3 hours, water was removed by decantation, followed by drying at 120 ° C. for 3 hours, and then firing in a muffle furnace at 400 ° C. for 3 hours in an air stream.

  The obtained fired product was cooled to room temperature in a desiccator, added with 10 g of 0.52 wt% -potassium nitrate aqueous solution, allowed to stand for 3 hours and then impregnated, and then water was removed by an evaporator, and then at 120 ° C. for 3 hours. The mixture was dried and reduced at 400 ° C. for 15 hours under a hydrogen flow to prepare a dehydrogenation catalyst.

[Test Example 1: Reaction test A]
The dehydrogenation catalyst 10cc obtained above was centered in the length direction of a stainless steel reaction tube with an inner diameter of 12.6 mmφ x 300 mm and a 1/8 inch thermocouple protection tube at the center of the reaction tube cross section. The catalyst was packed so that the center of the catalyst layer was positioned on the top, and 10 cc of 1 mmφ spherical α-alumina beads were packed as a preheating layer on the upper side of the catalyst. The temperature was raised until the center temperature of the catalyst layer reached 300 ° C. under hydrogen flow (LHSV = 5.0; 50 cc / hr). Next, methylcyclohexane (MCH) was supplied to the reactor in an amount corresponding to LHSV = 2.0 (20 cc / hr) by a high-performance liquid chromatography pump (HPLC pump), and the flow rate of hydrogen was directly adjusted between MCH and hydrogen. The hydrogen gas amount was adjusted to 20 mol% with respect to the total gas amount. During the reaction, a reaction test was performed by adjusting the output of the electric furnace so that the center temperature of the catalyst layer was 300 ° C.

A gas-liquid separator is provided at the outlet of the reaction tube to separate the liquid product such as toluene and gas such as hydrogen gas generated by this dehydrogenation reaction, and the recovered liquid product and gas are each subjected to gas chromatography. Analyzed with According to this gas chromatography analysis, MCH conversion (%), toluene selectivity (%), toluene yield (%), and hydrogen generation (Ncc / h / cc-cat) after 2 hours and 24 hours from the start of the reaction. Asked.
The results are shown in Table 2. FIG. 2 shows the relationship between the MCH reaction temperature (° C.) and the equilibrium conversion rate (%). The equilibrium conversion of MCH at a reaction temperature of 300 ° C. is 96%.

[Test Example 2: Reaction test B]
After carrying out the reaction of Test Example 1, the reaction temperature was changed to 320 ° C. and the dehydrogenation reaction was continued for 3000 hours in order to carry out the accelerated life test. MCH conversion (%), toluene selectivity (%), toluene yield (%), and hydrogen generation (Ncc / h / cc-cat) after 3 hours, 300 hours and 3000 hours from the start of the reaction Asked. The results are shown in Table 2.

[MCH loading and required amount of dehydrogenation catalyst]
For example, when the hydrogen supply device of the present invention is mounted on a fuel cell vehicle that requires 5 kg of hydrogen loading capacity (56 Nm ³ , 100 km / h, 500 km continuous travel), the amount of MCH required for this hydrogen supply device is theoretically The amount of toluene that is 107 L (82 kg) and needs to be generated and recovered after the dehydrogenation reaction is theoretically 88 L (77 kg). The required amount of the dehydrogenation catalyst required to generate 5 kg of hydrogen in 5 hours is the MCH conversion rate under the dehydrogenation reaction conditions where the catalyst performance is 320 ° C., normal pressure, and LHSV = 2.0. Is 91%, toluene selectivity is 99%, and toluene yield is 90%, the hydrogen generation rate is 943 Ncc / h / cc-cat, and the required amount of catalyst is about 12 L. The size of the catalyst packed bed is 20 cm in diameter × 38 cm in length.

[The amount of heat required for endothermic dehydrogenation]
The dehydrogenation reaction is an endothermic reaction, and in the case of MCH, ΔH = 205 kJ / mol. Therefore, when obtaining the hydrogen generation rate of 943 Ncc / h / cc-cat per unit volume, it is necessary to dehydrogenate MCH at a rate of 167 mol / hr, resulting in an endotherm of 34,153 kJ / hr. . When the necessary amount of heat is covered by electric power, the electric power of 9.5 kWhr is calculated from the formula of theoretical conversion amount 1 kcal = 4.184 kJ = 1.162 × 10 ⁻³ kWhr. This power is about 10% of the maximum output (usually about 90 kW) of the fuel cell mounted on the fuel cell vehicle, and can be handled using a part of the power generated by the fuel cell. is there. Therefore, by increasing the output of the fuel cell installed with this system in a practical range, the operating chassis that operates with a safe system with less potential danger is installed with the required hydrogen at room temperature and pressure. Is considered possible.

  The hydrogen supply device for mounting an operating housing of the present invention is such that the dehydrogenation catalyst used for this can achieve a conversion rate of 90% or more for the dehydrogenation of hydrogenated aromatics at a relatively low reaction temperature of about 300 ° C. In addition, since it has a high reaction selectivity of 98% or more, the hydrogenated aromatics can be stably dehydrogenated over a long period of time in a simple fixed bed reactor, and large-scale hydrogen purification Hydrogen can be supplied without using a device. For example, hydrogen can be supplied to a fuel cell by being mounted on a moving body such as an automobile, an aircraft, a ship, etc., a household generator, a vending machine, etc. together with a fuel cell. Can be supplied. Therefore, a fuel cell can be operated by mounting hydrogenated aromatics at normal temperature and normal pressure, and it has a high industrial value as a system with less potential danger.

FIG. 1 is a flowchart showing a system concept of a hydrogen supply device for a fuel cell for an operating chassis according to an embodiment of the present invention using methylcyclohexane (MCH). FIG. 2 is a graph showing the relationship between the reaction temperature (° C.) and the equilibrium conversion rate (%) when MCH is dehydrogenated and converted to toluene.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... MCH tank 1, 2 ... Liquid feed pump, 3 ... Dehydrogenation reactor, 3a ... Raw material inlet, 3b ... Product discharge port, 4 ... Reactor heater, 5 ... Gas-liquid separator, 5a ... Gas component Outlet, 5b ... Liquid component, 6 ... Hydrogen purifier, 6a, 6b ... Adsorption vessel, 7 ... Hydrogen compression pump, 8 ... Buffer tank, 9 ... Gas-liquid separator, 9a ... Gas component outlet, 9b ... Liquid component, 10a , 10b ... Heating heater for regeneration, 11 ... Toluene tank, 12 ... Introduction switching means, 13a, 13b ... Extraction switching means, 14 ... Combustor, 15 ... Exhaust.

Claims (20)

  It is a hydrogen supply device for a fuel cell for an operating chassis that is mounted on the operating chassis together with the fuel cell and supplies purified hydrogen to the fuel cell, a raw material tank for loading liquid hydrogenated aromatics at room temperature and normal pressure, and dehydration A dehydrogenation catalyst having an equilibrium reaction rate of 90% or more at a reaction temperature of 300 ° C. for an elementary reaction is charged, and the corresponding aromatics and hydrogen are separated by dehydrogenation of the hydrogenated aromatics. A dehydrogenation reactor to be generated, a gas-liquid separator that separates an aromatic-based liquid component and a hydrogen-based gas component generated in the dehydrogenation reactor, and the gas-liquid separator filled with an adsorbent And a hydrogen purifier for adsorbing and removing an impurity gas other than hydrogen from the gas component separated in step (b).   2. The hydrogen supply device for a fuel cell for an operating chassis according to claim 1, wherein the operating chassis is a vehicle, an aircraft, a ship, a stationary fuel cell power source, or a device provided with a stationary fuel cell power source.   The hydrogen supply apparatus for a fuel cell for an operating chassis according to claim 1 or 2, wherein the hydrogenated aromatic is one or a mixture of two or more selected from the group consisting of cyclohexane, methylcyclohexane, decalin and methyldecalin. .   The raw material tank for loading liquid hydrogenated aromatics is partitioned by a movable partition plate, and can be used to store dehydrogenation products that recover the space for the volume reduction of the consumed raw material It is a raw material tank, The hydrogen supply apparatus of the fuel cell for operating frames in any one of Claims 1-3.   The dehydrogenation catalyst charged in the dehydrogenation reactor is a catalyst in which a catalytic metal and an alkaline metal are supported on a porous γ-alumina support. Hydrogen supply device. The porous γ-alumina support has a surface area of 150 m ² / g or more, a pore volume of 0.55 cm ³ / g or more, an average pore diameter of 90 to 300 mm, and a pore diameter of 90 to 300 mm relative to the total pore volume. The hydrogen supply device for a fuel cell for an operating enclosure according to claim 5, wherein the proportion of the pores has a physical property of 60% or more.   The porous γ-alumina support alternately changes the pH value of the alumina hydrogel between the alumina hydrogel dissolution pH region and the boehmite gel precipitation pH region, and the pH from at least one of the pH regions to the other pH region. The hydrogen supply device for a fuel cell for an operating enclosure according to claim 5 or 6, which is obtained through a pH swing step of growing an alumina hydrogel crystal by adding an alumina hydrogel-forming substance upon fluctuation.   The hydrogen supply device for a fuel cell for a working enclosure according to any one of claims 5 to 7, wherein the catalyst metal is platinum and the alkaline metal is potassium.   9. The hydrogen supply device for a fuel cell for an operating enclosure according to claim 8, wherein the supported amount of platinum is 0.3 to 2.0% by weight and the supported amount of potassium is 0.001 to 1.0% by weight.   When impregnating the porous γ-alumina support with the platinum compound solution, the pH value of the impregnating solution is adjusted between 1.8 and 3.0, and the degree of metal dispersion of the noble metal after catalysis is 60. The hydrogen supply device for a fuel cell for an operating enclosure according to any one of claims 5 to 9, wherein the hydrogen supply device is at least%.   The dehydrogenation catalyst is impregnated with a porous γ-alumina support and dried with a platinum compound solution, and then calcined. The obtained catalyst metal-supported calcined product is impregnated with an alkaline metal compound solution and dried. The hydrogen supply device for a fuel cell for an operating enclosure according to any one of claims 5 to 10, which is prepared by performing final hydrogen reduction directly without firing the obtained alkaline metal-supported dried product.   The catalyst metal-supported calcined product impregnated with a solution of an alkaline metal compound is prepared by drying under dry conditions of room temperature to 200 ° C and 0.5 to 24 hours prior to final hydrogen reduction. The hydrogen supply apparatus of the fuel cell for working bodies in any one of -11.   The working housing according to any one of claims 5 to 12, wherein the final hydrogen reduction is performed using a hydrogen stream under a reduction condition of a temperature of 350 to 550 ° C and a time of 0.5 to 48 hours. Fuel cell hydrogen supply device.   The dehydrogenation reaction conditions in the dehydrogenation reactor are a reaction temperature of 250 to 350 ° C and an LHSV of 1.0 to 5.0. Hydrogen supply device.   The hydrogen supply apparatus for a fuel cell for an operating enclosure according to any one of claims 1 to 14, wherein a hydrogen generation rate of a dehydrogenation catalyst charged in the dehydrogenation reactor is 900 Ncc / h / cc-cat or more.   The hydrogen supply device for a fuel cell for an operating enclosure according to any one of claims 1 to 15, wherein the adsorbent filled in the hydrogen purifier is zeolite.   The hydrogen purifier has a plurality of adsorption regions and switching means for switching and using the plurality of adsorption regions, and an unused adsorption region before the adsorption region in use is saturated by the switching means. The hydrogen supply device for a fuel cell for an operating enclosure according to any one of claims 1 to 16, wherein the adsorption region after use is regenerated.   The hydrogen supply device for a fuel cell for an operating enclosure according to any one of claims 1 to 17, wherein the regeneration process of the adsorption region is performed at a heating temperature of 100 to 250 ° C.   The recovery gas component recovered by desorption from the adsorption region in the regeneration process is condensed and returned to the raw material tank, or burned and discarded. Hydrogen supply device.   The thermal energy required for a dehydrogenation reactor and / or the heat energy required for a regeneration process is provided by the electric heater operated using a part of electric power generated by the fuel cell. A hydrogen supply device for a fuel cell for an operating enclosure as described in 1.

Images