JP2009073680A - Hydrogen production apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problems that the filling amount of a catalyst is reduced and the hydrogen production amount cannot be secured in comparison with a reforming reactor having the same volume when the temperature in a catalyst layer is made uniform. <P>SOLUTION: A hydrogen production apparatus is constituted of a mixer 7 for preparing a mixed gas 13 by mixing dimethyl ether 12 and steam 11, a mixed gas preheater 2, and a reforming reactor 1 provided with a reaction tube 102 filled with a reforming catalyst 101 for reforming a preheated mixed gas 14 into a reformed gas 15 containing hydrogen in a high concentration. The hydrogen production apparatus is characterized in that a fin 120 and a heat transfer resistor 121 are installed so that the heat transfer characteristic of the reaction tube 102 has a distribution in a longitudinal direction. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a hydrogen production apparatus for producing hydrogen through a reformer using dimethyl ether and water vapor as raw materials.

As one vision of the future society, the realization of a hydrogen energy society using hydrogen as an energy medium is attracting attention, and several promising hydrogen production methods are considered. The current mainstream hydrogen production method uses natural gas or liquefied petroleum gas as a raw material, and produces hydrogen by a steam reforming method in the presence of a catalyst at a reaction temperature of 700 ° C. or higher. In this method, since impurities such as sulfur are contained in the raw material, this pretreatment is necessary, and since the reaction temperature is high, it is necessary to use a material having high heat resistance for the reactor structural material.
The steam reforming of dimethyl ether (hereinafter referred to as DME) has less impurities such as sulfur compared to natural gas and liquefied petroleum gas because DME is a synthetic fuel, and Fukushima et al. (15th World hydrogen Energy Conference 30D-03 ( 2004)) shows that hydrogen can be produced at a temperature of 400 ° C. or less, and the possibility of hydrogen production at a temperature lower than that of the conventional method is shown.
The heat of hydrogen production in the conventional method requires a high temperature of 700 ° C. or more, and the heat of combustion of fossil fuel is used as this heat source. For this reason, during the hydrogen production, carbon dioxide is generated by fossil fuel combustion in the heat source in addition to the generated carbon dioxide accompanying the fuel reforming by the steam reforming method. When hydrogen is used as an energy source, there is a feature that carbon dioxide, which is a global warming gas, is not generated during combustion.

However, at present, the production is accompanied by the generation of carbon dioxide. Further, when the heat of combustion of fossil fuel is used as this heat source, air pollutants such as sulfur oxides are simultaneously generated in addition to carbon dioxide.
As described above, Japanese Patent Laid-Open Publication No. 2003-38957 discloses a hydrogen production method using DME, which has a possibility of reducing the environmental load compared to the prior art in hydrogen production.
Japanese Patent Laid-Open No. 11-10670 discloses a method of using DME that generates hydrogen at a lower temperature than natural gas and using an external heat source for steam reforming heat of DME as a prime mover fuel.
JP 2003-38957 A Japanese Patent Laid-Open No. 11-10670 JP 2006-45031 A JP 2004-352528 A JP 2004-107110 A Fukushima et al. (15th World hydrogen Energy Conference 30D-03 (2004))

  When hydrogen is produced by the above steam reforming process, heat necessary for steam reforming reaction (endothermic reaction) is supplied from the outside of the reforming reaction tube using a reforming reaction tube filled with a reforming catalyst. To do. At this time, the temperature of the catalyst layer in the reforming reaction tube is the heat balance between the amount of heat brought in by the raw material supplied to the catalyst layer, the amount of heat transferred from the outside of the reaction tube to the catalyst layer in the reaction tube, and the reaction heat of the steam reforming reaction. Determined by. A temperature distribution is generated in the longitudinal direction along the flow of the reaction fluid, but if the difference between the maximum temperature and the minimum temperature is large, deterioration at the point of heat resistance of the catalyst is accelerated, especially in the high temperature part. There was a problem that the reaction occurred, the product purity was lowered, and the product hydrogen production amount was lowered.

  As a means for homogenizing the temperature of the catalyst layer of the reforming reactor, Japanese Patent Application Laid-Open No. 2006-45031 “Hydrogen Production Device” discloses that part of the reformed gas discharged from the reforming reaction tube By mixing with the raw material, the heat quantity of the gas supplied to the reforming reactor is increased, and the temperature in the catalyst layer is made uniform by compensating for the endothermic component caused by the steam reforming reaction that occurs in the catalyst layer and suppressing the temperature drop. A method is disclosed. In this method, since the flow rate of the fluid flowing through the catalyst layer increases and the pressure loss increases, it is necessary to increase the supply pressure of the raw material gas, and accordingly, it is necessary to increase the pressure resistance of the system including the reaction tube, A cooler and a circulation blower are required to recycle a part of the reformed gas from the reforming reaction tube to the raw material supply side, which requires a large facility, and the reformed gas recycled to the raw material supply side is predetermined. The subject that the thermal energy for heating even to reactor supply temperature is needed arises.

  Japanese Patent Laid-Open No. 2004-352528, “Hydrogen Production System”, circulates a part of the combustion exhaust gas that has exited the heating side of the reforming reactor in a system that uses the combustion exhaust gas to heat the reforming reactor. A method of increasing the flow rate of the combustion exhaust gas for heating and making the temperature in the catalyst layer uniform by circulating to the combustion exhaust gas inlet at the reforming reactor inlet by a blower is disclosed. This method requires a cooler and a circulation blower to recycle the combustion exhaust gas, which requires a large amount of equipment. In addition, it exits the heating side of the reforming reactor that circulates to the combustion exhaust gas inlet at the reforming reactor inlet. The subject that the thermal energy for heating combustion exhaust gas to predetermined temperature is needed arises.

  Furthermore, Japanese Patent Application Laid-Open No. 2004-107110 discloses a method for equalizing the temperature in the catalyst layer by disposing a highly thermally conductive substance in the catalyst layer along the gas flow. Has been. In this method, there is a concern that the amount of hydrogen produced cannot be ensured because the catalyst filling amount is reduced as compared with the reforming reactor of the same volume.

  The present invention has been made to solve the above problems, and distributes heat transfer characteristics from the heat medium outside the reforming reaction tube to the catalyst inside the reforming reaction tube in the longitudinal direction of the reforming reaction tube. By keeping the part of the catalyst layer where the DME concentration is high at a low temperature, heat transfer is good at the part of the catalyst layer where the temperature is high (the temperature difference with the heat medium is small), and sufficient heat is supplied for the reaction. Thus, the present invention provides an effect of extending the catalyst life, increasing the amount of hydrogen production, and improving the purity of product hydrogen, and provides a hydrogen production apparatus that can efficiently produce hydrogen at low temperature using DME as a raw material.

  In order to solve the above problems, the present invention provides a dimethyl ether vaporizer and a steam generator for making dimethyl ether and water as raw materials into a gaseous state, a dimethyl ether steam mixer for mixing the vaporized dimethyl ether and steam, and the dimethyl ether. A mixed gas preheater that preheats a mixed gas of dimethyl ether and water vapor mixed by the steam mixer to a predetermined reformer supply temperature, and reforms the mixed gas preheated by the mixed gas preheater to reduce the hydrogen concentration. A hydrogen production apparatus comprising a reforming reactor equipped with a reaction tube filled with a reforming catalyst that is a high reforming gas, wherein the heat transfer characteristics of the reaction tube have a distribution in the longitudinal direction A hydrogen production apparatus is provided.

  In the present invention, the heat transfer characteristic from the heat medium outside the reforming reaction tube to the catalyst inside the reforming reaction tube is distributed in the longitudinal direction of the reaction tube, so that the portion where the dimethyl ether concentration of the catalyst layer is high is obtained. Keep the temperature low and heat transfer is good in the high temperature part of the catalyst layer, so that the heat necessary for the reaction is sufficiently supplied, thereby extending the catalyst life, increasing the amount of hydrogen production, Hydrogen purity can be improved.

  Embodiments of a hydrogen production apparatus according to the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing an embodiment of a hydrogen production apparatus according to the present invention. FIG. 2 is a schematic diagram showing an example of a reaction tube of the reforming reactor shown in FIG. FIG. 3 is a graph showing the temperature distribution in the longitudinal direction of the process gas in the reaction tube.

  As shown in FIG. 1, the hydrogen production apparatus according to the present invention includes a dimethyl ether (DME) 12 and a water vapor generator 5 and a DME vaporizer 6 for converting water 11 into a gaseous state, and a vaporized gaseous state. A DME / steam mixer 7 for mixing DME and steam, a mixed gas preheater 2 for preheating a mixed gas 13 of DME and steam to a predetermined reformer supply temperature, and a premixed mixed gas 14 of DME and steam are provided. The reforming reactor 1 having a reaction tube filled with a reforming catalyst introduced to reform the reformed gas 15, and heat-recovered from the reformed gas 15 to preheat dimethyl ether (DME) 12 and water 11 as raw materials The water preheater 3 and the DME preheater 4 are configured.

  In FIG. 1, the reforming reactor 1, the mixed gas preheater 2, the steam generator 5, and the DME vaporizer 6 are each heated by the heat medium 23. As the heat medium 23, combustion exhaust gas, water vapor, or heat medium oil can be applied. Specifically, water vapor and exhaust gas generated at nuclear power plants, thermal power plants, steelworks, chemical factories, garbage incinerators, etc. can be used directly or via an intermediate heat exchanger. 1 shows a configuration in which the heat medium 23 is sequentially circulated in the order of the reforming reactor 1, the mixed gas preheater 2, the steam generator 5, and the DME vaporizer 6, but these devices are individually heated. It is also possible to supply a medium, or it is possible to heat with an electric heater or the like without using a heat medium.

  A plurality of reaction tubes 102 shown in FIG. 2 are provided in parallel in the reforming reactor 1, and a preheated mixed gas 14 of DME and water vapor is distributed to each reaction tube 102. As shown in FIG. 2, a catalyst layer 101 filled with a reforming catalyst is disposed inside the reaction tube 102, and when the preheated mixed gas 14 of DME and steam passes through the catalyst layer 101, As a result of the reforming reaction, the hydrogen-rich reformed gas 15 is discharged from the reaction tube 102. In the reforming reactor 1, a heating medium 23 is supplied to the upper part of the reaction tube 102 near the inlet of the mixed gas 14 in order to supply heat necessary for the steam reforming reaction. The heat medium 23 is cooled by transferring heat, and is discharged from the lower part of the reaction tube 102 in the vicinity of the outlet of the reformed gas 15.

  According to the above configuration, the DME 12 passes through the DME preheater 4 and the DME vaporizer 6, and the water 11 passes through the water preheater 3 and the water vapor generator 5 to become gaseous respectively. -It is supplied to the steam mixer 7. The DME / steam mixed gas 13 that has passed through the DME / steam mixer 7 is preheated to a predetermined reformer supply temperature by the mixed gas preheater 2. The preheated DME / steam mixed gas 14 is supplied to the reforming reactor 1.

  In the reforming reactor 1, when the preheated DME / steam mixed gas 14 passes through the catalyst layer 101 filled in the reaction tube 102, the reforming reactor 1 becomes a hydrogen-rich reformed gas 15 by the steam reforming reaction. Spill from. The reformed gas 15 exchanges heat with the raw water 11 and DME 12 in the water preheater 3 and the DME preheater 4, respectively, and is discharged as the reformed gas 15 to the next process. The heat medium 23 first exchanges the amount of heat necessary for the steam reforming reaction in the reforming reactor 1, then exchanges heat with the DME / steam mixed gas 13 in the mixed gas preheater 2, and then the steam generator. Heat is exchanged with water at 5, and heat is exchanged with raw material DME at the DME vaporizer 6, and a necessary amount of heat is supplied by each device.

  A steam reforming reaction occurs in the catalyst layer 101 inside the reaction tube 102 of the reforming reactor 1. Usually, the amount of reaction is particularly large at the inlet portion where the flow rate of DME, which is a raw material, and water is large (when the raw material gas is supplied from the upper portion of the catalyst layer).

  The temperature of the catalyst layer 101 includes the amount of heat brought by the raw material supplied to the catalyst layer 101, the amount of heat transferred from the outside of the reaction tube 102 to the catalyst layer 101 in the reaction tube 102, and the reaction heat of the steam reforming reaction (endothermic reaction). Although determined by the balance, the temperature of the upper part of the catalyst layer 101 having a large steam reforming reaction amount decreases, the upper temperature as shown in the longitudinal temperature distribution of the reaction tube 102 in FIG. 3 decreases, and the lower temperature is higher than the upper part. become.

  Note that the temperature distribution in this example is such that the reaction tube 102 is filled with a catalyst having catalytic characteristics in which the amount of hydrogen and impurities generated varies depending on the temperature shown in FIG. It is obtained when the tube is supplied from the upper end and discharged from the lower end.

  If the difference between the maximum temperature and the minimum temperature is large, deterioration particularly in the heat resistance of the catalyst is rapid, and side reactions outside the design may occur due to catalyst heat resistance, resulting in decreased product purity and decreased product hydrogen production. There was a problem that. Therefore, by distributing the heat transfer characteristics from the heat medium outside the reforming reaction tube to the catalyst inside the reforming reaction tube in the longitudinal direction of the reforming reaction tube, the portion where the DME concentration in the catalyst layer is high And heat transfer is good at the high temperature part of the catalyst layer (the temperature difference with the heat medium is small), so that the heat necessary for the reaction is sufficiently supplied, thereby extending the catalyst life and increasing the amount of hydrogen production. Thus, it is possible to provide a hydrogen production apparatus that can effectively produce hydrogen at a low temperature using dimethyl ether as a raw material.

  An example of a reaction tube having a specific distribution of heat transfer characteristics in the longitudinal direction will be described with reference to the following examples.

(Example 1)
FIG. 5 is a schematic diagram showing an example of the reaction tube 102 in which the heat transfer characteristics are distributed in the longitudinal direction. The same parts as those in FIG. 2 are denoted by the same reference numerals, and the description of the configuration is omitted.

  In this embodiment, the heat transfer promoting fins 120 are arranged on the lower outer surface of the reaction tube 102 installed in the reforming reactor 1. The reaction tube 102 is filled with a catalyst 111. The preheated DME / steam mixed gas 14 is supplied from the upper end of the reaction tube 102, causes a steam reforming reaction in the packed bed of the catalyst 111, and flows out as the reformed gas 15 from the lower end of the reaction tube 102. The heat necessary for the steam reforming reaction is given by a heat medium supplied to the outside of the reaction tube 102 of the reforming reactor 1. In this embodiment, the heat medium 23 is supplied from the upper part of the reforming reactor 1 and discharged from the lower part.

  Thereby, it can be set as the reaction tube by which heat transfer is promoted in the lower part of reaction tube 102, ie, the downstream. From the viewpoint of catalyst life, if excessive organic matter (including raw material DME) is present under high temperature conditions, carbon is deposited on the catalyst surface, leading to a decrease in activity. Therefore, in the portion where the DME concentration near the inlet of the reaction tube 102 is high It is desirable that the temperature is low. In addition, if the reaction is not advanced in the shortest possible time in the part where the temperature in the downstream part of the reactor is high, the deterioration of the catalyst is accelerated due to the above-described carbon deposition, or a side reaction outside the design assumption occurs, resulting in a decrease in product purity. However, there is a problem that the amount of product hydrogen production decreases. By using the reaction tube of the present embodiment, the portion of the catalyst layer at the upper portion of the reaction tube where the DME concentration is high is kept at a low temperature because of low heat conductivity. Moreover, heat transfer is good at the high temperature (the temperature difference with the heat medium is small) of the catalyst layer at the lower part of the reaction tube, and sufficient heat necessary for the reaction is supplied.

  FIG. 6 shows the temperature distribution in the longitudinal direction of the reaction tube in this example. A fin 120 that promotes heat transfer was attached from the outlet (lower end) of the reaction tube to a length that was ½ of the total length of the reaction tube 102. As shown in the figure, the temperature of the fin mounting portion increases due to the effect of the fin 120. Thereby, the amount of hydrogen production increases.

  From the temperature distribution of FIG. 6, the heat transfer promoting fins 120 are arranged from the outlet of the reaction tube 102 to a portion having a length of ¼ or more and 3/4 or less of the total length of the reaction tube 102. As a result, the temperature of the lower portion of the substrate increases and the effects of the present invention can be obtained efficiently.

  With the above description, the following effects can be obtained.

(1) Since the vicinity of the inlet of the reaction tube having a high concentration of organic matter (including raw material DME) is kept at a low temperature, carbon deposition that causes a decrease in catalyst activity is suppressed, so that the catalyst life is extended.

(2) Since the heat transfer is good at the high temperature portion of the catalyst layer where the temperature difference with the heat medium at the bottom of the reaction tube is small, the amount of hydrogen production increases.

(3) By attaching fins to the downstream part of the reactor to promote heat transfer, the reaction proceeds in a short time in the part where the temperature is high, so side reactions outside the design are unlikely to occur and the product hydrogen purity is improved. To do.

(Example 2)
FIG. 7 is a schematic diagram showing another example of a reaction tube having a distribution of heat transfer characteristics in the longitudinal direction. The same parts as those in FIG. 2 are denoted by the same reference numerals, and the description of the configuration is omitted.

  In this example, a heat transfer resistor 121 serving as a heat transfer resistance was disposed on the upper outer surface of the reaction tube 102 installed in the reforming reactor 1. The heat transfer resistor is composed of a substance having a heat insulation effect in a high temperature state, and the material thereof includes at least one of zirconium oxide, cerium oxide, aluminum oxide, calcium oxide, and magnesium oxide as a component. .

  In FIG. 2, the reaction tube 102 is filled with a catalyst 111. The preheated DME / steam mixed gas 14 is supplied from the upper end of the reaction tube 102, causes a steam reforming reaction in the packed bed of the catalyst 111, and flows out from the lower end of the reaction tube 102 as a reformed gas 15 that is a gas having a high hydrogen concentration. . Heat necessary for the steam reforming reaction is given by the heat medium 23 supplied to the outside of the reaction tube 102 of the reforming reactor 103. In this embodiment, the heat medium 23 is supplied from the upper part and discharged from the lower part. As a result, heat transfer is suppressed by the action of the heat transfer resistor 121 at the upper portion, that is, the upstream side of the reaction tube 102, and the reaction tube 102 can be made to promote heat transfer at the lower portion, that is, the downstream side. From the viewpoint of catalyst life, if excessive organic substances (including raw material DME) are present under high temperature conditions, carbon will be deposited on the surface of the catalyst, leading to a decrease in catalytic activity, so the DME concentration near the inlet of the reaction tube 102 is high. It is desirable that the temperature is low in the part. In addition, if the reaction is not advanced in the shortest possible time in the part where the temperature in the downstream part of the reactor is high, the deterioration of the catalyst is accelerated due to the above-described carbon deposition, or a side reaction outside the design assumption occurs, resulting in a decrease in product purity. However, there is a problem that the amount of product hydrogen production decreases. By using the reaction tube of the present embodiment, the portion of the catalyst layer at the upper portion of the reaction tube where the DME concentration is high is kept at a low temperature because of low heat conductivity.

  From the temperature distribution in FIG. 3, the heat transfer resistor 121 is disposed in a portion having a length that is ¼ or more and ¾ or less of the total length of the reaction tube from the inlet of the reaction tube 102. Thus, heat transfer is promoted at the lower portion, that is, the downstream side, and the effect of the present invention can be obtained efficiently.

  Thereby, the following effects are acquired.

(1) Since the vicinity of the inlet of the reaction tube having a high concentration of organic matter (including raw material DME) is kept at a low temperature, carbon production that causes a decrease in catalyst activity is suppressed, and thus the catalyst life is extended.

Example 3
FIG. 8 is a schematic diagram showing another example of a reaction tube having a distribution of heat transfer characteristics in the longitudinal direction. The same parts as those in FIG. 2 are denoted by the same reference numerals, and the description of the configuration is omitted.

  In this embodiment, fins 120 for promoting heat transfer are arranged on the lower outer surface of the reaction tube 102 installed in the reforming reactor 1, and a heat transfer resistor 121 serving as heat transfer resistance is provided on the upper outer surface. Arranged. The reaction tube 102 is filled with a catalyst 111. The preheated DME / steam mixed gas 14 is supplied from the upper end of the reaction tube 102, causes a steam reforming reaction in the packed bed of the catalyst 111, and flows out from the lower end of the reaction tube 102 as the reformed gas 15 having a high hydrogen gas concentration. Heat necessary for the steam reforming reaction is given by the heat medium 23 supplied to the outside of the reaction tube 102 of the reforming reactor 103. In this embodiment, the heat medium 23 is supplied from the upper part and discharged from the lower part. Thereby, it can be set as the reaction tube 102 by which heat transfer is promoted in the lower part of the reaction tube 102, ie, downstream.

  From the viewpoint of catalyst life, if excessive organic substances (including raw material DME) exist under high temperature conditions, carbon will be deposited on the catalyst surface, leading to a decrease in activity. It is desirable to be. In addition, if the reaction is not advanced in the shortest possible time in the part where the temperature in the downstream part of the reactor is high, the deterioration of the catalyst is accelerated due to the above-described carbon deposition, or a side reaction outside the design assumption occurs, resulting in a decrease in product purity. However, there is a problem that the amount of product hydrogen production decreases.

  By using the reaction tube of the present embodiment, the portion of the catalyst layer at the upper portion of the reaction tube where the DME concentration is high is kept at a low temperature because of low heat conductivity. Moreover, heat transfer is good at the high temperature (the temperature difference with the heat medium is small) of the catalyst layer at the lower part of the reaction tube, and sufficient heat necessary for the reaction is supplied.

  FIG. 8 shows the temperature distribution in the longitudinal direction of the reaction tube in this example. Fins that promote heat transfer were attached from the outlet (lower end) of the reaction tube to a length that was ½ of the total length of the reaction tube. A heat transfer resistor serving as a heat transfer resistance was attached from the reaction tube inlet (upper end) to a half length of the total length of the reaction tube. As shown in this figure, the temperature of the reaction tube is kept lower in the heat transfer resistor mounting portion than in the conventional example due to the effect of the heat transfer resistor. On the other hand, due to the effect of the fin, the temperature is increased at the fin mounting portion.

  From the temperature distribution in FIG. 8, the heat transfer resistor 121 is disposed from the inlet of the reaction tube 102 to a portion having a length that is not less than 1/4 and not more than 3/4 of the total length of the reaction tube. 120 is disposed in a portion having a length of 1/4 or more and 3/4 or less of the total length of the reaction tube from the outlet of the reaction tube 102, so that the temperature of the upper portion of the reaction tube 102 is lowered and the lower portion of the reaction tube 102 is lowered. As a result, the effect of the present invention can be obtained efficiently.

  Thereby, the following effects are acquired.

(1) Since the vicinity of the inlet of the reaction tube having a high concentration of organic matter (including raw material DME) is kept at a low temperature, carbon production that causes a decrease in catalyst activity is suppressed, and thus the catalyst life is extended.

(2) Since the heat transfer is good at the high temperature (the temperature difference with the heat medium is small) of the catalyst layer at the bottom of the reaction tube, the amount of hydrogen production increases.

(3) By attaching fins to the downstream part of the reactor to promote heat transfer, the reaction proceeds in a short time in the part where the temperature is high, so side reactions outside the design are unlikely to occur and the product hydrogen purity is improved. To do.

1 is a block diagram showing an embodiment of a hydrogen production apparatus according to the present invention. The schematic diagram which shows an example of the reaction tube of the reforming reactor shown in FIG. The graph which shows the temperature distribution of the longitudinal direction of a reaction tube. The characteristic view of the catalyst which shows the relationship between the production amount of hydrogen and an impurity with temperature. The schematic longitudinal cross-sectional view which shows an example of the reaction tube which gave distribution to the heat-transfer characteristic in the longitudinal direction. The graph which shows the temperature distribution of the longitudinal direction of the reaction tube shown in FIG. The schematic longitudinal cross-sectional view which shows another example of the reaction tube which gave distribution to the heat-transfer characteristic in the longitudinal direction. The graph which shows the temperature distribution of the longitudinal direction of the reaction tube which shows another example which gave distribution to the heat transfer characteristic in the longitudinal direction.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Reforming reactor, 2 ... Mixed gas preheater, 3 ... Water preheater, 4 ... Dimethyl ether (DME) preheater, 5 ... Steam generator, 6 ... Dimethyl ether (DME) vaporizer, 7 ... Dimethyl ether ( DME) / steam mixer, 11 ... water, 12 ... dimethyl ether (DME), 13 ... dimethyl ether (DME) / steam mixed gas, 14 ... preheated dimethyl ether (DME) / steam mixed gas, 15 ... reformed gas, 23 ... heat medium, 101 ... catalyst layer, 102 ... reaction tube, 111 ... catalyst, 120 ... fin, 121 ... heat transfer resistor,

Claims (8)

A dimethyl ether vaporizer and a steam generator for gasifying dimethyl ether and water as raw materials, a dimethyl ether steam mixer for mixing the vaporized dimethyl ether and steam, and a mixture of dimethyl ether and steam mixed by the dimethyl ether steam mixer. Filled with a mixed gas preheater that preheats the mixed gas to a predetermined reformer supply temperature, and a reforming catalyst that reforms the mixed gas preheated by this mixed gas preheater to form a reformed gas having a high hydrogen concentration A hydrogen production apparatus comprising a reforming reactor equipped with a reaction tube, wherein the heat transfer characteristics of the reaction tube have a distribution in the longitudinal direction. The hydrogen production apparatus according to claim 1, wherein fins for promoting heat transfer are disposed on a part of the outer surface of the reaction tube in the reforming reactor. 3. The hydrogen according to claim 2, wherein the heat transfer promoting fin is disposed in a portion having a length of ¼ or more and 3/4 or less of a total length of the reaction tube from an outlet of the reaction tube. Manufacturing equipment. The hydrogen production apparatus according to any one of claims 1 to 3, wherein a heat transfer resistor serving as a heat transfer resistance is disposed on a part of the outer surface of the reaction tube in the reforming reactor. 5. The hydrogen production apparatus according to claim 4, wherein the heat transfer resistor is disposed in a portion having a length of ¼ or more and 3/4 or less of a total length of the reaction tube from an inlet of the reaction tube. The reaction tube in the reforming reactor is provided with a heat transfer resistor serving as a heat transfer resistance on a part of the outer surface of the reaction tube in the vicinity of the reaction tube inlet, and the reaction tube outlet in the reaction tube in the reforming reactor. 2. The hydrogen production apparatus according to claim 1, wherein fins for promoting heat transfer are disposed on a part of the outer surface of the nearby reaction tube. The heat transfer resistor is disposed in a portion having a length of 1/4 or more and 3/4 or less of the total length of the reaction tube from the inlet of the reaction tube, and the fin is 1/2 of the total length of the reaction tube from the outlet of the reaction tube. The hydrogen production apparatus according to claim 6, wherein the hydrogen production apparatus is disposed in a portion having a length of 4 or more and 3/4 or less. The hydrogen production according to any one of claims 4 to 7, wherein the heat transfer resistor includes at least one of zirconium oxide, cerium oxide, aluminum oxide, calcium oxide, and magnesium oxide as a component. apparatus.

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