JP2007039322A - Reforming method and reforming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a reforming method and a reforming apparatus which are capable of solving problems encountered when two kinds of catalysts are used while the advantage in the case where air only is distributed among the respective catalyst layers is realized and are capable of realizing reduction in apparatus size. <P>SOLUTION: The reforming apparatus is one having a structure in which air only is distributed between two-stage catalyst layers 12A and 12B connected in series, wherein each of the catalyst layers 12A and 12B is packed with an oxidation reforming catalyst which by itself can catalyze both the partial oxidation and steam reforming of a fuel. Alternatively, the apparatus may be one having a structure in which a double cylindrical catalyst container composed of two superposed cylinders, there is a two-stage catalyst layer composed of a catalyst layer formed by packing the inside of the inner one of the two cylinders with an oxidation reforming catalyst and another catalyst layer formed by packing the annular space between the two cylinders with an oxidation reforming catalyst, and the gas is successively passed through the respective catalyst layers from the inner catalyst layer to the outer catalyst layer in a manner in which the flow directions in the respective catalyst layers are opposite to the other (in a manner in which the flow returns). <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a reforming method and a reformer that generate hydrogen by a steam reforming reaction of fuel.

A reformer that obtains a hydrogen-containing gas by a steam reforming reaction of a fuel includes a steam reforming catalyst layer, and the steam reforming reaction of the fuel is promoted in the steam reforming catalyst layer. In this case, since the steam reforming reaction of the fuel is generally an endothermic reaction represented by the following formula, in order to maintain this reaction and obtain a predetermined hydrogen-containing gas, the steam reforming catalyst layer is heated. Need to supply.
Fuel + aH ₂ O → bCO ₂ + cH ₂ (1)

As a method of supplying heat to the steam reforming catalyst layer, a method of supplying heat from the outside of the steam reforming catalyst layer by heat exchange, and a steam reforming catalyst by causing an exothermic reaction in the steam reforming catalyst layer There is a method of supplying heat from the inside of the layer. Comparing the two, especially in the case of a vehicle-mounted reformer, it requires a short time start-up and a high-speed load change, so the temperature distribution of the steam reforming catalyst layer is controlled by controlling the amount of heat supplied from the outside. However, since it is more advantageous to perform control by controlling the amount of heat generated internally, it is more advantageous to adopt the latter heat supply method than the former heat supply method. The exothermic reaction generated in the steam reforming catalyst layer is a reaction that oxidizes a part of the fuel. Since this reaction uses a very small amount of air compared to stoichiometric air, the combustion products contain a large amount of CO and H ₂ instead of CO ₂ and H ₂ O. Therefore, this reaction is called a partial oxidation reaction. The partial oxidation reaction is represented by the following formula.
Fuel + O2 → CO + H ₂ (partial oxidation reaction: exothermic) (2)

  As an example of the reformer that supplies heat by such a partial oxidation reaction, for example, there is one described in Patent Document 1 below. FIG. 19 is a schematic configuration diagram of a reformer described in Patent Document 1, and FIG. 20 is a schematic configuration diagram of another reformer described in Patent Document 1.

  The reformer 1 shown in FIG. 19 has a two-stage configuration in which two reformers 2 are connected in series. The reformer 2 has an oxidation catalyst layer 3 that is filled with an oxidation catalyst that promotes a partial oxidation reaction (exothermic reaction) on the upstream side, and a reforming that promotes a steam reforming reaction (endothermic reaction) on the downstream side. It has a reforming catalyst layer 4 filled with a catalyst. In the reformer 1, the mixed gas of fuel, water vapor, and air is distributed to the reformers 2 to control the amount of heat generated and the amount of heat absorbed, so that the temperature of the oxidation catalyst layer 3 is the oxidation catalyst. It prevents the temperature from rising above the heat-resistant temperature.

  The reformer 5 shown in FIG. 20 also has a two-stage configuration in which two reformers 2 are connected in series. The structure of the modified body 2 is as described above. In the reformer 2, the mixed gas of fuel and steam is supplied to the first reformer 2, while only the partial oxidation reaction air is distributed to the reformers 2, The endothermic amount is controlled to prevent the temperature of the oxidation catalyst layer 3 from being raised above the heat resistance temperature of the oxidation catalyst.

JP 2002-326801 A Japanese Patent No. 3482367 JP-A-2005-212808

The conventional reformers 1 and 5 have the following problems.
(1) Since the reformer 1 distributes the mixed gas of fuel, water vapor, and air, the distribution flow rate increases and the size of the flow control device increases. Moreover, since it is necessary to cope with changes in temperature and pressure, the control device is complicated and expensive. On the other hand, when only air is distributed, a mixer for mixing the mixed gas of fuel and water vapor and air is required. It is easier than distributing a mixed gas of air and air, and the size of the flow control device is also reduced. Furthermore, when the mixed gas of fuel, water vapor, and air is distributed, the composition of the mixed gas is constant, so that the calorific value is proportional to the mixed gas flow rate. However, if the flow distribution characteristic of the mixed gas to the reformer 2 (catalyst layer) at each stage changes, the reactivity may decrease. Therefore, the adjustment amount of the calorific value by adjusting the mixed gas distribution flow is air. It becomes smaller than the case of distributing only.
(2) In addition, the reformers 1 and 5 are simply connected in series with the two-stage reformers 2 (catalyst layers), so that the size of the reformers 1 and 5 is large. If it is, it is disadvantageous. Further, in the reformers 1 and 5, the peak temperature in the reformed body 2 (catalyst layer) is reduced (flattened temperature distribution) by distributing the mixed gas or air. In order to secure a sufficient margin, it is desirable to further reduce the peak temperature (flattening the temperature distribution). Furthermore, since the reformers 1 and 5 use two types of catalysts (an oxidation catalyst and a reforming catalyst) in the reformer 2 (catalyst layer) at each stage, the adjustment ratio of these catalysts can be adjusted. Filling work is difficult due to labor, and a partition is also required to prevent these catalysts from mixing with each other.

  On the other hand, the present inventors have currently reformed using a catalyst that promotes a partial oxidation reaction of fuel and a steam reforming reaction of fuel (hereinafter, such a catalyst is referred to as an oxidation reforming catalyst). The development of the vessel is in progress. The reformer using this oxidation reforming catalyst can solve the problems in the case of using the above two types of catalysts (oxidation catalyst and reforming catalyst). However, also in this case, since the reaction rate of the above formula (2) is generally higher than the reaction rate of the above formula (1), the temperature distribution in the gas flow direction in the catalyst layer becomes as shown in FIG. That is, in the graph of FIG. 21, the horizontal axis represents the position in the gas flow direction (longitudinal direction) of the catalyst layer 7 formed by filling the catalyst filling portion 6 such as a cylindrical body with the oxidation reforming catalyst, and the vertical axis represents the gas flow. The temperature of the catalyst layer 7 at each position in the direction is shown. As can be seen from the temperature distribution in FIG. 21, a local high temperature portion is generated upstream of the catalyst layer 7.

  The reaction when the air amount (oxygen amount) is set so that the exothermic amount due to the partial oxidation reaction and the endothermic amount due to the steam reforming reaction are equal is called autothermal, but the partial oxidation reaction (exothermic reaction) and the steam reforming reaction are called. Since the reaction rate is different from that of (endothermic reaction), a locally high temperature portion having a peak temperature of about 800 ° C. is generated in the catalyst layer 7 as shown in FIG. At this time, if the heat resistance temperature of the oxidation reforming catalyst is sufficiently high, there is no problem. Usually, however, the peak temperature of the catalyst layer 7 exceeds the heat resistance temperature of the oxidation reforming catalyst (for example, about 550 ° C.). Measures to reduce it are necessary.

  Therefore, in view of the above circumstances, the present invention takes advantage of the case of distributing only air and solves the problems in the case of using two types of catalysts, and the size reduction (space saving) of the reformer. Another object of the present invention is to provide a reforming method and a reformer capable of further reducing the peak temperature of the catalyst layer (further flattening of the temperature distribution).

The reforming method of the first invention that solves the above problem is a reforming method for obtaining a hydrogen-containing gas by a steam reforming reaction of fuel,
A plurality of catalyst layers formed by filling a catalyst filling portion with a catalyst that promotes the partial oxidation reaction of the fuel and the steam reforming reaction of the fuel are connected in series, from the previous catalyst layer to the subsequent catalyst layer. And let gas flow in sequence,
The mixed gas of fuel and water vapor is supplied to the first catalyst layer of the plurality of catalyst layers, while the oxidizing gas is distributed to each of the plurality of catalyst layers, and the first catalyst layer Is supplied with the mixed gas after being mixed with the mixed gas, and is supplied with the exhaust gas after being mixed with the exhaust gas discharged from the catalyst layer in the preceding stage of the catalyst layer to the catalyst layer of the other stage. Features.

The reforming method of the second invention is the reforming method of the first invention,
The flow rate of the oxidizing gas distributed to the catalyst layers in the plurality of stages is set to a flow rate at which the peak temperatures of the catalyst layers in the plurality of stages are substantially equal.

The reformer of the third invention is a reformer configured to obtain a hydrogen-containing gas by a steam reforming reaction of fuel.
A plurality of catalyst layers formed by filling a catalyst filling portion with a catalyst that promotes the partial oxidation reaction of the fuel and the steam reforming reaction of the fuel are connected in series, from the previous catalyst layer to the subsequent catalyst layer. And the gas flow in sequence,
The mixed gas of fuel and water vapor is supplied to the first catalyst layer of the plurality of catalyst layers, while the oxidizing gas is distributed to each of the plurality of catalyst layers, and the first catalyst layer Is mixed with the mixed gas by the mixing means and then supplied together with the mixed gas, and the other catalyst layer is mixed with the exhaust gas discharged from the previous catalyst layer of the catalyst layer by the other mixing means. The exhaust gas is supplied together with the exhaust gas.

The reformer of the fourth invention is the reformer of the third invention,
The flow rate of the oxidizing gas distributed to each of the plurality of catalyst layers is set to a flow rate at which peak temperatures of the catalyst layers of the plurality of stages are substantially equal.

The reformer of the fifth invention is a reformer configured to obtain a hydrogen-containing gas by a steam reforming reaction of fuel,
It has a catalyst container with a multiple cylinder structure in which a plurality of cylinders are stacked,
A catalyst layer formed by filling a catalyst for promoting a partial oxidation reaction of the fuel and a catalyst for promoting a steam reforming reaction of the fuel into an innermost cylinder of the plurality of cylinders; A multi-stage catalyst layer structure comprising a catalyst for promoting the partial oxidation reaction of the fuel and another catalyst layer filled with a catalyst for promoting the steam reforming reaction of the fuel, and The configuration is such that the gas is circulated sequentially from the inner catalyst layer to the outer catalyst layer with the gas flow direction of each stage catalyst layer reversed,
The mixed gas of fuel and water vapor is supplied to the innermost first catalyst layer of the plurality of catalyst layers, while the oxidizing gas is distributed to each of the plurality of catalyst layers so that the first step The catalyst layer is mixed with the mixed gas by the mixing means and then supplied together with the mixed gas, and the other catalyst layer is supplied with the exhaust gas discharged from the previous catalyst layer of the catalyst layer and the other mixing means. The mixed gas is supplied together with the exhaust gas after mixing.

A reformer of a sixth invention is a reformer configured to obtain a hydrogen-containing gas by a steam reforming reaction of fuel,
It has a catalyst container with a multiple cylinder structure in which a plurality of cylinders are stacked,
A catalyst layer formed by filling a catalyst for promoting a partial oxidation reaction of the fuel and a steam reforming reaction of the fuel into an innermost cylinder of the plurality of cylinders; and A multi-stage catalyst layer structure comprising a catalyst layer that is filled with a catalyst that promotes a partial oxidation reaction of the fuel and a steam reforming reaction of the fuel, and an outer side from the inner catalyst layer. To the catalyst layer, the gas flow direction of each stage of the catalyst layer is reversed, and the gas is sequentially flowed,
The mixed gas of fuel and water vapor is supplied to the innermost first catalyst layer of the plurality of catalyst layers, while the oxidizing gas is distributed to each of the plurality of catalyst layers so that the first step The catalyst layer is mixed with the mixed gas by the mixing means and then supplied together with the mixed gas, and the other catalyst layer is supplied with the exhaust gas discharged from the previous catalyst layer of the catalyst layer and the other mixing means. The mixed gas is supplied together with the exhaust gas after mixing.

The reformer of the seventh invention is the reformer of the fifth or sixth invention,
The oxidizing gas distributed to the second catalyst layer of the plurality of catalyst layers is distributed by an oxidizing gas distribution pipe inserted into the first catalyst layer.

The reformer of the eighth invention is the reformer of the seventh invention,
The mixing means for mixing the exhaust gas from the first stage catalyst layer and the oxidizing gas distributed to the second stage catalyst layer is such that the downstream end of the innermost cylinder is narrower than the catalyst layer portion. The downstream end portion of the oxidizing gas distribution pipe is positioned inside the exhaust gas outlet flow path.

The reformer of the ninth invention is the reformer of the eighth invention,
In the exhaust gas outlet channel, a plurality of baffle plates having a notch portion serving as a gas channel portion on the outer peripheral portion are arranged in series such that the circumferential positions of the notch portions of adjacent baffle plates are different from each other. It is characterized by having been arranged in.

The reformer of the tenth invention is the reformer of the eighth or ninth invention,
The oxidizing gas distribution pipe is characterized in that a downstream end face is closed and an oxidizing gas outlet is formed on the side face of the downstream end.

Moreover, the reformer of the eleventh invention is the reformer of any of the fifth to tenth inventions,
A plurality of heat transfer fins are disposed in each of the plurality of catalyst layers.

The reformer of the twelfth invention is the reformer of the eleventh invention,
The heat transfer fins are arranged only in the upstream portion of the catalyst layers of the plurality of stages.

The reformer of the thirteenth aspect of the invention is the reformer of any of the fifth to twelfth aspects of the invention,
The flow rate of the oxidizing gas distributed to each of the plurality of catalyst layers is set to a flow rate at which peak temperatures of the catalyst layers of the plurality of stages are substantially equal.

Further, the modification method of the fourteenth invention is the modification method of the first or second invention,
The downstream end of the gas flow direction in the last catalyst layer of the plurality of catalyst layers is cooled by a cooling means.

Further, the reforming method of the fifteenth invention is the reforming method of the fourteenth invention,
The temperature of the exhaust gas discharged from the last catalyst layer is measured, and the cooling capacity of the cooling means is controlled so that the temperature measurement value becomes a predetermined temperature.

Further, the reforming method of the sixteenth invention is the reforming method of the fourteenth or fifteenth invention,
As the fuel, dimethyl ether is used,
A catalyst capable of suppressing methanation is used as a catalyst for promoting the partial oxidation reaction of the fuel and the steam reforming reaction of the fuel.

The reformer of the seventeenth invention is the reformer of any of the fifth to thirteenth inventions,
Forming a double-structure gas flow path comprising an inner gas flow path and an outer gas flow path between the first catalyst layer and the second catalyst layer of the plurality of catalyst layers;
The mixed gas flows back and forth between the inner gas channel and the outer gas channel, and then is mixed with the oxidizing gas and supplied to the first catalyst layer.

The reformer of the eighteenth invention is the reformer of any of the third to thirteenth and seventeenth inventions,
It has a cooling means which cools the downstream end part of the gas distribution direction in the last catalyst layer of the plurality of catalyst layers.

The reformer of the nineteenth invention is the reformer of the eighteenth invention,
Temperature measuring means for measuring the temperature of the exhaust gas discharged from the final stage catalyst layer;
And a temperature control means for controlling the cooling capacity of the cooling means so that the temperature measurement value of the temperature measuring means becomes a predetermined temperature.

The reformer of the twentieth invention is the reformer of the eighteenth or nineteenth invention,
The fuel is dimethyl ether;
The reformer characterized in that the catalyst that promotes the partial oxidation reaction of the fuel and the steam reforming reaction of the fuel is a catalyst that can suppress methanation.

  According to the reforming method of the first invention or the reformer of the third invention, the peak temperature of each catalyst layer is reduced (the temperature distribution is flattened) by distributing the oxidizing gas to each catalyst layer of a plurality of stages. In addition, since only the oxidizing gas is distributed, the distribution flow rate is smaller and the adjustment of the distribution flow rate is easier than the case of distributing the mixed gas of fuel, water vapor and oxidizing gas (air). The size of the battery is also reduced, and the amount of heat generated can be adjusted. Furthermore, since each catalyst layer is formed by filling a catalyst filling portion with a catalyst that promotes a partial oxidation reaction of fuel and a steam reforming reaction of fuel, two types of catalysts (an oxidation catalyst and a reforming catalyst) are used. Compared with the case of using a), the adjustment of the distribution ratio is unnecessary, so that the catalyst filling operation becomes very easy and the structure of the reformer is simplified because the partition is unnecessary. You can also

  Further, according to the reforming method of the second invention or the reformer of the fourth invention, the flow rate of the oxidizing gas distributed to each catalyst layer is set to a flow rate at which the peak temperature of each catalyst layer becomes substantially equal. Further, the peak temperature of each catalyst layer can be reduced (temperature distribution is flattened).

  Further, according to the reformer of the fifth or sixth invention, the peak temperature of each catalyst layer can be reduced (the temperature distribution is flattened) by distributing the oxidizing gas to each catalyst layer in a plurality of stages. In addition, since only the oxidizing gas is distributed, the distribution flow rate is smaller and the distribution flow rate can be easily adjusted, and the size of the flow control device is reduced, compared with the case where a mixed gas of fuel, water vapor and air is distributed. The amount of adjustment is also great.

  Further, the reformer of the fifth invention has a catalyst container having a multiple cylinder structure in which a plurality of cylinders are stacked, and the fuel is contained in the innermost cylinder of the plurality of cylinders. A catalyst layer comprising a catalyst for promoting a partial oxidation reaction and a catalyst for promoting a steam reforming reaction of the fuel, a catalyst for promoting a partial oxidation reaction of the fuel between the plurality of cylinders, and the fuel The catalyst layer is composed of a plurality of catalyst layers each composed of another catalyst layer filled with a catalyst that promotes the steam reforming reaction, and the catalyst layers of each step are arranged from the inner catalyst layer to the outer catalyst layer. The gas flow direction is reversed (turned back), and the gas is sequentially flowed. In the sixth aspect of the invention, a catalyst container having a multiple cylinder structure in which a plurality of cylinders are stacked is provided. And partial oxidation reaction of the fuel inside the innermost cylinder of the plurality of cylinders A catalyst layer formed by filling a catalyst for promoting the steam reforming reaction of the fuel, and a catalyst for promoting the partial oxidation reaction of the fuel and the steam reforming reaction of the fuel are filled between the plurality of cylinders. In this way, the gas is flowed sequentially from the inner catalyst layer to the outer catalyst layer with the gas flow direction of each catalyst layer reversed from the inner catalyst layer to the outer catalyst layer. By adopting such a configuration, the reformer becomes smaller compared to a case where a plurality of catalyst layers are simply connected in series, which is very disadvantageous when the setting space is limited, for example, in a vehicle. It is. In addition, since heat conduction (heat exchange) occurs between the inner catalyst layer and the outer catalyst layer, the peak temperature of each catalyst layer is further reduced (temperature distribution) compared to the case where the oxidizing gas is simply distributed. And a sufficient margin for the heat resistance of the catalyst can be secured.

  Furthermore, in the reformer of the sixth invention, since the catalyst in each catalyst layer is a catalyst that promotes the partial oxidation reaction of the fuel and the steam reforming reaction of the fuel, two types of catalysts (an oxidation catalyst and a reforming catalyst) are used. Compared with the case of using a catalyst), it is very easy to fill the catalyst because it is not necessary to adjust the distribution ratio, and the structure of the reformer is simplified because no partition is required. It can also be.

  Further, according to the reformer of the seventh aspect of the invention, the oxidizing gas distributed to the second stage catalyst layer is distributed by the oxidizing gas distribution pipe inserted into the first stage catalyst layer. Preheating can be performed by the heat of the first stage catalyst layer, and the peak temperature of the first stage catalyst layer can be further reduced (flattening of temperature distribution).

  According to the reformer of the eighth aspect of the invention, the mixing means for mixing the exhaust gas from the first stage catalyst layer and the oxidizing gas distributed to the second stage catalyst layer is provided downstream of the innermost cylinder. Since the downstream end of the oxidizing gas distribution pipe is positioned inside the exhaust gas outlet flow path, which is narrower than the catalyst layer, the mixing section is formed in the reformer. Therefore, the exhaust gas and the oxidizing gas can be mixed well by the mixing means (mixing unit) without particularly installing a mixer.

  According to the reformer of the ninth aspect of the present invention, the exhaust gas outlet channel is provided with a plurality of baffle plates each having a cutout portion serving as a gas channel portion on the outer peripheral portion, and the adjacent baffle plates are notched. Since the circumferential positions of the parts are arranged in series so as to be different from each other, the exhaust gas and the oxidizing gas meander and pass through the notch part (gas flow path part) of the baffle plate, Mix well.

  Further, according to the reformer of the tenth aspect of the invention, the oxidizing gas distribution pipe has a configuration in which the downstream end face is closed and the oxidizing gas outlet is formed on the side face of the downstream end. The oxidizing gas is blown from the outlet to the exhaust gas flowing through the exhaust gas outlet passage in a direction substantially perpendicular to the flow direction of the exhaust gas. It can be mixed well.

  According to the reformer of the eleventh aspect of the present invention, since a plurality of heat transfer fins are arranged in each catalyst layer, heat between the inner catalyst layer and the outer catalyst layer is obtained by these heat transfer fins. Since conduction (heat exchange) is further promoted, the peak temperature of each catalyst layer can be further reduced (temperature distribution is flattened).

  According to the reformer of the twelfth aspect of the present invention, since a plurality of heat transfer fins are disposed in each catalyst layer, heat between the inner catalyst layer and the outer catalyst layer is obtained by these heat transfer fins. Since conduction (heat exchange) is further promoted, the peak temperature of each catalyst layer can be further reduced (temperature distribution is flattened). In addition, since the heat transfer fins are disposed only in the upstream portion of each catalyst layer, that is, in the local high temperature portion, it is possible to reduce the heat capacity and the cost.

  According to the reformer of the thirteenth aspect of the invention, the flow rate of the oxidizing gas distributed to each catalyst layer is set to a flow rate at which the peak temperature of each catalyst layer is substantially equal, so that the peak of each catalyst layer is more appropriately The temperature can be reduced (temperature distribution can be flattened).

  Further, according to the reforming method or reformer of the fourteenth or eighteenth aspect of the invention, the downstream end in the gas flow direction in the last catalyst layer of the plurality of catalyst layers is cooled by the cooling means. Therefore, the gas temperature at the downstream end of the last stage catalyst layer is lowered, and the CO concentration in the reformed gas at the exit of the last stage catalyst layer is reduced from the viewpoint of the equilibrium reaction. Therefore, even when the reformed gas is subsequently passed through the CO converter (LTS) and the CO remover in order to reduce CO, the CO converter reduces the CO shift reaction amount of the reformed gas. By reducing the amount of heat generated by the reaction, it is possible to suppress the temperature rise of the low temperature CO shift catalyst, so that even if the amount of the low temperature CO shift catalyst is small, the CO concentration in the reformed gas can be brought close to the equilibrium state. Thus, the CO concentration in the reformed gas at the CO converter outlet can be reduced. This also makes it possible to reduce the amount of air for the CO selective oxidation reaction in the CO remover, and to reduce the number of stages of the CO remover.

  Further, according to the reforming method or reformer of the fifteenth or nineteenth invention, the temperature of the exhaust gas (reformed gas) discharged from the last stage catalyst layer is measured, and this temperature measurement value is a predetermined temperature. In order to control the cooling capacity of the cooling means so that the gas temperature at the downstream end of the last-stage catalyst layer can be reliably lowered to the predetermined temperature, the 14th or The effect of the seventeenth invention can be exhibited reliably.

  According to the reforming method or reformer of the sixteenth or twentieth invention, a catalyst capable of suppressing methanation is used as a catalyst for promoting the partial oxidation reaction of the fuel and the steam reforming reaction of the fuel. Even if dimethyl ether, for example, is used as the fuel, when the downstream end of the gas flow direction in the last catalyst layer is cooled by the cooling means to lower the gas temperature, the production of methane is promoted and the methane concentration is increased. The increase can be prevented.

  Further, according to the reformer of the seventeenth aspect of the invention, the inner gas passage and the outer gas passage are provided between the first catalyst layer and the second catalyst layer of the plurality of catalyst layers. And the mixed gas flows back and forth between the inner gas channel and the outer gas channel, and then mixes with the oxidizing gas to mix the first stage catalyst layer. The mixed gas is preheated by heat exchange with the first and second catalyst layers while flowing through the double-structure gas flow path, and then flows into the first catalyst layer For this reason, a steam reforming reaction occurs near the inlet of the first stage catalyst layer, and the reforming efficiency is improved. Furthermore, the effect of reducing the peak temperatures of the first and second catalyst layers can be obtained by the heat exchange.

  Embodiments of the present invention will be described below in detail with reference to the drawings.

<Embodiment 1>
FIG. 1 is a configuration diagram of a reformer (reforming method) according to Embodiment 1 of the present invention.

  As shown in FIG. 1, the reformer 11 according to the first embodiment obtains a hydrogen-containing gas (reformed gas) by a steam reforming reaction of fuel. The two-stage catalyst layers 12A and 12B are Connected in series, gas is circulated sequentially from the first (first) catalyst layer 12A to the second (second) catalyst layer 12B. The reformer 11 is configured to distribute only the partial oxidation reaction air (oxidizing gas) to the two catalyst layers 12A and 12B.

  That is, a mixed gas of fuel and water vapor sent from a mixed gas supply device (not shown) is supplied to the first catalyst layer 12A of the two catalyst layers 12A and 12B, while an air supply device (not shown) The air (oxidizing gas) sent from is distributed to the two catalyst layers 12A and 12B, mixed with the first catalyst layer 12A by the mixer 14 (mixing means) and then mixed with the mixed gas. After being supplied and mixed in the other stage (second stage) catalyst layer 12B with the exhaust gas discharged from the previous stage (first stage) catalyst layer 12A by the mixer 15 (other mixing means), It is configured to be supplied together with exhaust gas.

  The flow rate of air distributed to the two-stage catalyst layers 12A and 12B is set to a flow rate at which the peak temperatures of the two-stage catalyst layers 12A and 12B are substantially equal (including the case where they are equal). What kind of value this set flow rate (distributed flow rate) should be specifically determined may be appropriately determined by performing a test or the like. The air distribution flow rate to each of the catalyst layers 12A and 12B is adjusted by setting the flow rate adjustment valve opening control or blower output control in the air supply device. In this case, the air may be branched from one air supply device and supplied to the two-stage catalyst layers 12A and 12B, respectively, or may be supplied from the two air supply devices to the two-stage catalyst layers 12A and 12B, respectively. May be.

Each of the catalyst layers 12A and 12B in each stage is a catalyst that promotes a partial oxidation reaction of the fuel and a steam reforming reaction of the fuel in the catalyst filling portions 13A and 13B such as a cylindrical body (hereinafter referred to as such a catalyst). Is referred to as an oxidation reforming catalyst). As the oxidation reforming catalyst may be, for example, Cu, Zn, those made of Al ₂ O _3. Specific examples include a Cu—Zn catalyst and a catalyst obtained by adding Al ₂ O ₃ to the Cu—Zn catalyst. Further, as the steam reforming fuel, a hydrocarbon-based fuel is used. Specific examples include city gas, LPG, kerosene, methanol, ethanol, dimethyl ether and the like.

As an example, the steam reforming reaction when dimethyl ether is used is as follows.
C ₂ H ₆ O + H ₂ O → 2CH ₃ OH
CH ₃ OH + H ₂ O → CO ₂ + 3H ₂
CO ₂ + H ₂ → CO + H ₂ O
CO + 3H ₂ → CH ₄ + H ₂ O

Further, as a result of such a steam reforming reaction occurring in the catalyst layers 12A and 12B, the general gas composition of the exhaust gas (reformed gas) discharged from the second-stage catalyst layer 12B is as follows.
CO 3%
CO ₂ 16%
H ₂ O 21%
N ₂ 14%
H ₂ 46%

  Note that examples of the fuel and the oxidation reforming catalyst and examples of the gas composition of the steam reforming reaction and the exhaust gas (reformed gas) are the same in other embodiments described later.

  As described above, according to the reforming method or reformer of the first embodiment, the peak temperature of each catalyst layer 12A, 12B is reduced by distributing air to the two catalyst layers 12A, 12B. (Temperature distribution can be flattened), and since only air is distributed, the distribution flow rate is smaller and the adjustment of the distribution flow rate is easier than when distributing a mixed gas of fuel, water vapor and air. The size of the flow control device is also reduced, and the amount of heat generation is also large. Further, since each of the catalyst layers 12A and 12B is formed by filling the catalyst filling portions 13A and 13B with an oxidation reforming catalyst that promotes the partial oxidation reaction of the fuel and the steam reforming reaction of the fuel, there are two types. Compared with the use of other catalysts (oxidation catalyst and reforming catalyst), it is not necessary to adjust the distribution ratio, making it much easier to fill the catalyst, and the partition is not necessary. The configuration of the mass device 11 can be simplified.

  Further, since the flow rate of air distributed to the catalyst layers 12A and 12B is set to a flow rate at which the peak temperatures of the catalyst layers 12A and 12B are substantially equal, the peak temperatures of the catalyst layers 12A and 12B are more appropriately reduced (temperature Distribution can be flattened).

  In the above reformer 11, the number of catalyst layers is two, but the number of catalyst layers is not limited to this and may be three or more. For example, in the case of three stages, three stages of catalyst layers formed by filling the catalyst reforming portion with the oxidation reforming catalyst are connected in series, and sequentially from the first catalyst layer to the subsequent catalyst layer (first stage, The gas is circulated in the order of the second and third stages, and the mixed gas of fuel and water vapor is supplied to the first catalyst layer of the plurality of catalyst layers while air (oxidation) Gas) is distributed to each of the three catalyst layers, mixed with the mixed gas in the mixer and then supplied to the first catalyst layer together with the mixed gas. The catalyst layer of the first stage is the catalyst layer of the previous stage of the catalyst layer (the first catalyst layer for the second catalyst layer, the second catalyst layer for the third catalyst layer) ) And the exhaust gas that has been exhausted from the other gas mixer and then supplied together with the exhaust gas.

<Embodiment 2>
FIG. 2A is a longitudinal sectional view showing a configuration of a reformer according to Embodiment 2 of the present invention, and FIG. 2B is a sectional view taken along line AA in FIG. 3A is a diagram showing another configuration example of the mixing unit, FIG. 3B is a perspective view of a main part of FIG. 3A, and FIG. 4 is a diagram showing another configuration example of the mixing unit, FIG. FIG. 3 is a view showing a temperature distribution of a catalyst layer of the reformer. 6 (a) is a longitudinal sectional view showing another configuration of the reformer according to Embodiment 2 of the present invention, and FIG. 6 (b) is a sectional view taken along line BB in FIG. 6 (a). FIG.

  As shown in FIGS. 2 (a) and 2 (b), the reformer 21 of the second embodiment obtains a hydrogen-containing gas (reformed gas) by a steam reforming reaction of fuel, and has a diameter. The catalyst container 24 has a double cylindrical structure in which two cylindrical bodies 22 and 23 having different sizes are stacked. The reformer 21 includes a catalyst layer 25A in which the inside (catalyst filling portion) of the inner cylindrical body 22 of the two cylindrical bodies 22 and 23 is filled with an oxidation reforming catalyst, and two cylindrical bodies. It has a two-stage catalyst layer structure composed of another catalyst layer 25B filled with an oxidation reforming catalyst between 22 and 23 (catalyst filling portion), and the gas flow is indicated by arrows in FIG. As shown, the gas flow directions of the catalyst layers 25A, 25B in each stage are reversed (turned back) sequentially from the inner (first stage) catalyst layer 25A to the outer (second stage) catalyst layer 25B. The gas is circulated. That is, the gas flows in the right direction in the figure as indicated by the arrow in the first catalyst layer 25A, and the gas flows in the left direction in the figure by folding back as indicated by the arrow in the second stage catalyst layer 25B.

  The reformer 21 is configured to distribute only the partial oxidation reaction air (oxidizing gas) to the two catalyst layers 25A and 25B. That is, a mixed gas of fuel and water vapor sent from a mixed gas supply device (not shown) flows into the cylindrical body 22 from the inlet portion 26 provided on the upstream end surface 22a of the inner cylindrical body 22, While being supplied to the (first-stage) catalyst layer 25A, air (oxidation gas) sent from an air supply device (not shown) is distributed to the two-stage catalyst layers 25A and 25B, and the first-stage catalyst layer. 25A is mixed with the mixed gas by a mixer 27 (mixing means), and then flows into the cylindrical body 22 from the inlet 26 together with the mixed gas, and is supplied to the other stage (second stage) catalyst layer. 25B is configured to be mixed with the exhaust gas discharged from the previous (first) catalyst layer 25A and mixed with the exhaust gas after being mixed by the mixing unit 28 (another mixing means).

  The air distributed to the second-stage catalyst layer 25B is distributed by an air distribution pipe 29 (oxidation gas distribution pipe) inserted into the first-stage catalyst layer 25A. The air distribution pipe 29 passes through the upstream inlet portion 26 of the inner cylindrical body 22 and is inserted into the cylindrical body 22, passes through the central portion of the first-stage catalyst layer 25 </ b> A, and reaches the tip (downstream end). Part) protrudes from the first-stage catalyst layer 25 </ b> A to the downstream end of the cylindrical body 22.

  The mixing unit 28 for mixing the exhaust gas from the first-stage catalyst layer 25A and the air distributed to the second-stage catalyst layer 25B has a downstream end portion of the inner cylindrical body 22 as a catalyst layer. The front end portion (downstream end portion) 29a of the air distribution pipe 29 is positioned inside the exhaust gas outlet passage 30 that is narrower than the 22A portion. The mixed gas of the exhaust gas and the air that has exited the mixing unit 28 (exhaust gas outlet flow path 30) has a downstream end surface 22b of the inner cylindrical body 22 and an upstream end surface 23a of the outer cylindrical body 23. Is folded back through the space portion (flow path portion) 32 and flows into the upstream side of the second-stage catalyst layer 25B. The exhaust gas (reformed gas) discharged from the second-stage catalyst layer 25B is flush with the downstream end surface 23b of the outer cylindrical body 23 (the upstream end surface 22a of the inner cylindrical body 22). ) To the outside of the catalyst container 24. In addition, as a structure of the mixing part 28, in order to further improve the mixing performance, it is good also as a structure as shown to Fig.3 (a), FIG.3 (b), or FIG.

  In the mixing section 28 shown in FIGS. 3A and 3B (for convenience of explanation, the exhaust gas outlet channel 30 is represented by a dashed line in FIG. 3), in addition to the configuration shown in FIG. In addition, three (not limited to three) baffle plates 31 are provided in the exhaust gas outlet channel 30. These baffle plates 31 are substantially disk-shaped, and have a cutout portion 31a serving as a gas flow path portion on the outer peripheral portion, and the circumferential positions of the cutout portions 31a between the adjacent baffle plates 31. Are arranged in the exhaust gas outlet channel 30 in series so as to be different from each other. Accordingly, the exhaust gas from the first-stage catalyst layer 25A and the air from the air distribution pipe 29 pass through the notch portions (gas flow path portions) 31a of the baffle plates 31 as shown by arrows in FIG. It will flow while meandering.

  4, in addition to the configuration of FIG. 2, the downstream end surface 29b of the air distribution pipe 29 is closed, and a plurality of air outlets 29c are provided on the side surface of the downstream end 29a. Is formed. Therefore, the air is blown out from the outlet 2c to the exhaust gas flowing through the exhaust gas outlet passage 30 in a direction substantially perpendicular to the flow direction of the exhaust gas. Note that the configuration of FIG. 4 and the configuration of FIG. 3 may be combined.

  The distribution flow rate of air to the two-stage catalyst layers 25A and 25B is the same as that in the first embodiment. That is, the flow rate of air distributed to the two-stage catalyst layers 25A and 25B is set to a flow rate at which the peak temperatures of the two-stage catalyst layers 25A and 25B are substantially equal (including the case where they are equal). What kind of value this set flow rate (distributed flow rate) should be specifically determined may be appropriately determined by performing a test or the like. The air distribution flow rate to each of the catalyst layers 25A and 25B is adjusted by setting the flow rate adjustment valve opening control and blower output control in the air supply device. In this case, it may be branched from one air supply device and supplied to the two-stage catalyst layers 25A and 25B, respectively, or may be supplied from the two air supply devices to the two-stage catalyst layers 25A and 25B, respectively. May be.

  As described above, according to the reformer 21 of the second embodiment, the peak temperature of each catalyst layer 25A, 25B is reduced (temperature distribution) by distributing air to the two catalyst layers 25A, 25B. In addition, since only air is distributed, the distribution flow rate is smaller and the adjustment of the distribution flow rate is easier than when distributing a mixed gas of fuel, water vapor and air. The size of the device is also reduced, and the amount of heat generated can be adjusted.

  In addition, a catalyst container 24 having a double cylindrical structure formed by overlapping two cylindrical bodies 22 and 23 is provided, and oxidation reforming is performed inside the inner cylindrical body 22 of the two cylindrical bodies 22 and 23. A catalyst layer 25A formed by filling the catalyst and another catalyst layer 25B formed by filling an oxidation reforming catalyst between the two cylindrical bodies 22 and 23, and a two-stage catalyst layer structure, Since the gas flow direction of each of the catalyst layers 25A and 25B is reversed (turned back) sequentially from the catalyst layer 25A to the outer catalyst layer 25B, a plurality of catalyst layers are simply provided. Since the reformer 21 is smaller than the case where the two are connected in series, it is very advantageous when the setting space is limited, for example, for in-vehicle use.

  In addition, since heat conduction (heat exchange) occurs between the inner catalyst layer 25A and the outer catalyst layer 25B, each catalyst layer is further reduced as shown in FIG. The peak temperatures of 25A and 25B can be reduced (temperature distribution can be flattened), and a sufficient margin can be secured for the heat resistance of the catalyst. In the graph of FIG. 5, the horizontal axis represents the position of the catalyst layers 25A and 25B in the gas flow direction (longitudinal direction), and the vertical axis of the graph represents the temperature of the catalyst layers 25A and 25B at each position in the gas flow direction. . The dotted line a1 in the graph of FIG. 5 is the temperature distribution of the catalyst layer 25A when it is assumed that there is no heat conduction, and the dotted line a2 is the temperature distribution of the catalyst layer 25B when it is assumed that there is no heat conduction, a solid line. b1 represents the actual temperature distribution of the catalyst layer 25A when the heat conduction occurs, and the solid line b2 represents the actual temperature distribution of the catalyst layer 25B when the heat conduction occurs. As can be seen from this graph, the catalyst layers 25A and 25B both have a local high temperature portion upstream, but the temperature distribution is flattened by heat conduction (heat exchange) between the catalyst layers 25A and 25B. In any upstream part (high temperature part) of the catalyst layers 25A and 25B, the peak temperature is reduced.

  Further, according to the reformer 21 of the second embodiment, the air distributed to the second stage catalyst layer 25B is distributed by the air distribution pipe 29 inserted into the first stage catalyst layer 25A. The air can be preheated by the heat of the first-stage catalyst layer 25A, and the peak temperature of the first-stage catalyst layer 25A can be further reduced (temperature distribution flattened).

  Further, according to the reformer 21 of the second embodiment, as a mixing means for mixing the exhaust gas from the first-stage catalyst layer 25A and the air distributed to the second-stage catalyst layer 25B, A mixing portion 28 having a configuration in which the tip end portion (downstream end portion) 29a of the air distribution pipe 29 is positioned inside the exhaust gas outlet passage 30 in which the downstream end portion of the cylindrical body 22 is narrower than the catalyst layer 25A portion. However, since it is formed in the reformer 21, the exhaust gas and the air can be mixed well by the mixing unit 28 without particularly installing a mixer.

  Further, the plurality of baffle plates 31 having the cutout portions 31a serving as gas flow passage portions on the outer peripheral portion are arranged such that the circumferential positions of the cutout portions 31a between the adjacent baffle plates 31 are different from each other. When arranged in series in the passage 30, the exhaust gas and the oxidizing gas meander and pass through the notch portion (gas flow passage portion) 31a of the baffle plate 31, so that they are further mixed. The

  Further, when the air distribution pipe 29 is configured such that the downstream end face 29b is closed and the air outlet 29c is formed on the side surface of the downstream end 29a, the air is discharged from the outlet 29c. Since the exhaust gas flowing through the gas outlet channel 30 is blown out in a direction substantially perpendicular to the flow direction of the exhaust gas, the exhaust gas and the oxidizing gas can be further mixed.

  Further, according to the reformer 21 of the second embodiment, the oxidation reforming catalyst that promotes the partial oxidation reaction of the fuel and the steam reforming reaction of the fuel is also used. Compared to the case of using a high quality catalyst), it is very easy to fill the catalyst because it is not necessary to adjust the distribution ratio, and the structure of the reformer 21 is simplified because no partition is required. It can also be a thing.

  However, the present invention is not necessarily limited to the case where an oxidation reforming catalyst is used, and two types of catalysts (an oxidation catalyst and a reforming catalyst) are used in the same manner as in the past, and the upstream side of the catalyst layers 25A and 25B is used as an oxidation catalyst layer. The side can also be a reforming catalyst layer. Also in this case, the same effects as described above, that is, effects such as downsizing of the reformer 21 (space saving) and reduction of the peak temperatures of the catalyst layers 25A and 25B (flattening of temperature distribution) are obtained. Can do.

  In the reformer 21, the number of catalyst layers is two, but the number of catalyst layers is not limited to this and may be three or more. For example, in the case of three stages, a configuration as shown in FIG.

  That is, the reformer 36 shown in FIG. 6 includes a catalyst container 34 having a triple cylindrical structure in which three cylindrical bodies 22, 23, 34 are overlapped, and of the three cylindrical bodies 22, 23, 24. The innermost cylindrical body 22 of the catalyst layer 25A filled with the oxidation reforming catalyst, and between the three cylindrical bodies 22, 23, 24 (that is, between the cylindrical bodies 23, 24 and the cylindrical bodies 24, 34). Between the inner catalyst layer 25A and the outer catalyst layer 25C, and the catalyst of each stage is composed of the other catalyst layers 25B and 25C filled with the oxidation reforming catalyst. The gas flow direction of the layers 25A, 25B, and 25C is reversed (turned back), and the gas is circulated sequentially (in order of the first, second, and third stages). The mixed gas of fuel and water vapor is supplied to the innermost first catalyst layer 25 of the three stages of catalyst layers 22, 23, 24, while air (oxidation gas) is supplied to each of the three stages of catalyst layers 25A. , 25B, 25C, and mixed with the mixed gas by the mixing unit 27 (mixing means) to the first-stage catalyst layer 25A and then supplied together with the mixed gas, and the other stages (second stage, third stage) The first catalyst layers 25B and 25C are connected to the first catalyst layers 25A and 25B (for the second catalyst layer 25B, the first catalyst layer 25A and the third catalyst layer 25C). In contrast, the exhaust gas discharged from the second catalyst layer 25B) is mixed with the mixing unit 28 and the mixer 37 (another mixing means) and then supplied together with the exhaust gas.

  In this case, the outlet 33 of the intermediate cylindrical body 23 is connected to the inlet side of the mixer 37, and the outlet side of the mixer 37 is connected to the upstream end face 34a (the cylindrical body 22,. 23, which is flush with the end faces 22a and 23b of the 23), and is discharged from the second-stage catalyst layer 25B mixed by the mixer 37 through the inlet 38. A mixed gas of the gas and the distribution air from the air supply device is configured to flow into the upstream side of the outermost (third stage) catalyst layer 25C. Further, the exhaust gas (reformed gas) discharged from the third-stage catalyst layer 25C reaches the downstream end face 34b of the outermost cylindrical body 34 (which is flush with the end face 23a of the cylindrical body 23). It is discharged out of the catalyst container 35 from the provided outlet 39. About another structure, it is the structure similar to said reformer 21 (The same code | symbol is attached to the same part), The overlapping description here is abbreviate | omitted.

<Embodiment 3>
7A is a longitudinal sectional view showing the configuration of the reformer according to Embodiment 3 of the present invention, FIG. 7B is a sectional view taken along the line CC of FIG. 7A, and FIG. FIG. 3 is a view showing a temperature distribution of a catalyst layer of the reformer. FIG. 9 is a longitudinal sectional view showing another configuration of the reformer according to Embodiment 3 of the present invention, and FIG. 9B is a sectional view taken along the line D-D in FIG. 9A. . 7 and 9, the same reference numerals are given to the same parts as those in the second embodiment (see FIG. 2), and the detailed description thereof is omitted. 7 and 9 show an example of a two-stage catalyst layer configuration. However, the catalyst layer configuration of three or more stages may be used in the case of the second embodiment (see FIG. 6). It is the same.

  As shown in FIGS. 7 (a) and 7 (b), in the reformer 51 of the third embodiment, the heat transfer fins 52 and 53 are arranged in the two catalyst layers 25A and 25B, respectively. Yes. A plurality of heat transfer fins 52 (seven in the illustrated example) are provided on the outer peripheral surface of the air distribution pipe 29 by welding or the like, and extend radially toward the inner peripheral surface of the inner cylindrical body 22. A clearance is secured between the tip of the heat transfer fin 52 and the inner peripheral surface of the cylindrical body 22 in consideration of the thermal expansion of the heat transfer fin 52. A plurality of heat transfer fins 53 (seven in the illustrated example) are provided on the outer peripheral surface of the cylindrical body 22 by appropriate attachment means such as welding, and extend radially toward the inner peripheral surface of the outer cylindrical body 23. Yes. A clearance is also secured between the tip of the heat transfer fin 53 and the inner peripheral surface of the cylindrical body 23 in consideration of the thermal expansion of the heat transfer fin 53. The heat transfer fins 52 are provided over substantially the entire length from the upstream part to the downstream part of the first stage catalyst layer 25A, and the heat transfer fins 53 are also provided from the upstream part to the downstream part of the second stage catalyst layer 25B. It is provided over substantially the entire length. In addition, when it is set as the catalyst layer structure of 3 steps | paragraphs or more, a heat-transfer fin is provided also in the catalyst layer of the 3rd step | paragraph or later.

  According to the reformer 51 of the third embodiment, in addition to obtaining the same effects as those of the second embodiment, a plurality of heat transfer fins 52, 53 are provided on the catalyst layers 25A, 25B. By disposing, the heat transfer fins 52 and 53 further promote the heat conduction (heat exchange) between the inner catalyst layer 25A and the outer catalyst layer 25B. The peak temperature of each catalyst layer 25A, 25B can be reduced (temperature distribution is flattened).

  The heat transfer fins 51 are not limited to the outer peripheral surface of the air distribution pipe 29, and may be provided on the inner peripheral surface of the inner cylindrical body 22 as shown in FIGS. 9 (a) and 9 (b). In this case, a plurality of heat transfer fins 51 (seven in the illustrated example) are provided on the inner peripheral surface of the cylindrical body 22 by appropriate attachment means such as welding, and extend toward the outer peripheral surface of the air distribution pipe 29. Yes. Accordingly, in this case as well, the heat transfer fins 51 are radially similar to the above case (see FIG. 7). However, in consideration of the thermal expansion of the heat transfer fins 51, a clearance is secured between the tips of the heat transfer fins 51 and the air distribution pipe 29. In this case, since the heat transfer fins 51 are provided on the inner peripheral surface of the cylindrical body 22, the heat transfer fins 51 are provided on the outer peripheral surface of the air distribution pipe 29 as described above, and the tip of the heat transfer fin 51 and the cylinder are provided. Since the heat transfer (heat exchange) between the inner catalyst layer 25A and the outer catalyst layer 25B can be further promoted compared to the case where a clearance is provided between the inner peripheral surface of the body 22 and each catalyst, The temperature distribution of the layers 25A and 25B can be further flattened to further reduce the peak temperatures of the catalyst layers 25A and 25B.

<Embodiment 4>
FIG. 10 (a) is a longitudinal sectional view showing the configuration of the reformer according to Embodiment 4 of the present invention, FIG. 10 (b) is a sectional view taken along line EE in FIG. 10 (a), and FIG. FIG. 10C is a cross-sectional view taken along line FF in FIG. In FIG. 10, the same parts as those in the second embodiment (see FIG. 2) are denoted by the same reference numerals, and detailed description thereof is omitted. Further, FIG. 10 shows an example of a two-stage catalyst layer configuration, but it is possible to adopt a three-stage or more catalyst layer configuration as in the case of the third embodiment.

  In the third embodiment, heat transfer fins are provided over substantially the entire length of the catalyst layer, whereas in the fourth embodiment, heat transfer fins are provided only in the upstream portion (high temperature portion) of the catalyst layer. It has been.

  More specifically, as shown in FIGS. 10 (a) and 10 (b), in the reformer 61 of the third embodiment, the heat transfer fins 62 and 63 are provided in the two catalyst layers 25A and 25B, respectively. It is arranged. A plurality of heat transfer fins 62 (seven in the illustrated example) are provided on the outer peripheral surface of the air distribution pipe 29 by welding or the like, and extend radially toward the inner peripheral surface of the inner cylindrical body 22. A clearance is secured between the tips of the heat transfer fins 62 and the inner peripheral surface of the cylindrical body 22 in consideration of the thermal expansion of the heat transfer fins 62. The heat transfer fins 62 are disposed only in the upstream portion of the first-stage catalyst layer 25A. The heat transfer fins 62 are provided radially on the inner peripheral surface of the inner cylindrical body 22 in the same manner as the heat transfer fins 52 of the third embodiment (see FIG. 9), and the outer periphery of the air distribution pipe 29 You may make it ensure a clearance between surfaces. A plurality of heat transfer fins 63 (seven in the illustrated example) are provided on the outer peripheral surface of the cylindrical body 22 by appropriate attachment means such as welding, and extend radially toward the inner peripheral surface of the outer cylindrical body 23. Yes. A clearance is also secured between the tips of the heat transfer fins 63 and the inner peripheral surface of the cylindrical body 23 in consideration of thermal expansion of the heat transfer fins 63. The heat transfer fins 63 are disposed only in the upstream portion of the second-stage catalyst layer 25B.

  According to the reformer 61 of the fourth embodiment, in addition to obtaining the same effects as those of the second and third embodiments, the heat transfer fins 62 and 63 are located upstream of the catalyst layers 25A and 25B. Part, that is, only in the local high temperature part, the heat capacity can be reduced and the cost can be reduced.

  By the way, the CO concentration of the reformed gas (hydrogen-containing gas) generated by the reformers 11, 21, 36, 51, 61 of the first to fourth embodiments and discharged from these reformers 11 or the like is, for example, It is 4 to 5%, which is too high for use as a fuel cell fuel. For this reason, the reformed gas discharged from the reformer 11 and the like is then supplied to a fuel cell or the like after the CO concentration is sufficiently reduced in the CO converter (LTS) and the CO remover (FIG. 17). See: details below). Further, since the reformed gas discharged from the reformer 11 or the like has a high temperature (for example, 400 ° C.), it is cooled by a cooler until it reaches a temperature suitable for a low-temperature CO shift catalyst (for example, 200 ° C.) of the CO remover. After cooling, it is fed to the CO transformer.

  However, even if the temperature of the reformed gas is lowered by the cooler, the CO concentration remains high (see FIG. 12: details will be described later). When this reformed gas is supplied to the CO converter, the CO converter There is a problem that the temperature of the low-temperature CO shift catalyst is increased because the amount of the CO shift reaction of the reformed gas in the low-temperature CO shift catalyst layer increases and the calorific value increases. In addition, when the reformer 11 or the like has a limited installation space such as for in-vehicle use, a sufficient amount of the low-temperature CO shift catalyst cannot be used, so the CO concentration at the CO converter outlet is It does not reach equilibrium. Therefore, if the CO concentration in the reformed gas at the CO converter inlet is high, the CO concentration in the reformed gas at the CO converter outlet tends to be high, and further, the reformed gas in the subsequent CO remover. The CO selective oxidation reaction may increase the amount of air necessary for removing CO, or may increase the number of stages of CO converters.

  Therefore, in the following embodiment, the occurrence of such a problem is prevented by reducing the CO concentration in the reformed gas discharged from the reformer.

<Embodiment 5>
FIG. 11 is a block diagram of a reformer (reforming method) according to Embodiment 5 of the present invention, FIG. 12 is a graph showing the relationship between gas temperature and CO concentration, and FIG. 13 is gas temperature, CO concentration and CH _4. It is a graph which shows the relationship with a density | concentration.

  As shown in FIG. 11, a reformer 91 according to the fifth embodiment obtains a hydrogen-containing gas (reformed gas) by a steam reforming reaction of fuel, and the first embodiment (FIG. 1). As in the reformer 11, two stages of catalyst layers 92A and 92B are connected in series, and gas is sequentially transferred from the preceding (first stage) catalyst layer 922A to the subsequent stage (second stage) catalyst layer 92B. It is configured to circulate. The reformer 91 is configured to distribute only partial oxidation reaction air (oxidation gas) supplied from an air supply device (not shown) to the two catalyst layers 92A and 92B.

  In the illustrated example, an evaporator 93 is installed upstream of the reformer 91. The evaporator 93 includes a burner 94 and a tube 96 wound around the burner outer cylinder 95. The burner 94 burns fuel (dimethyl ether: DME) and air. In the mixer 97 (mixing means), air supplied from the air supply device is mixed with a mixed fluid of reformed fuel (DME) and water vapor supplied from a mixed fluid supply device (not shown). In the evaporator 93, the mixed fluid is circulated through the tube 96 and heated by the combustion exhaust gas of the burner 94 to generate a mixed gas. Then, this mixed gas is supplied to the first-stage catalyst layer 92A. The air supplied from the air supply device to the second stage catalyst layer 92B is mixed with the exhaust gas discharged from the first stage catalyst layer 92A by the mixer 107 (another mixing means) and then the exhaust gas. Supplied with

  The flow rate of air distributed to the two-stage catalyst layers 92A and 92B is set to a flow rate at which the peak temperatures of the two-stage catalyst layers 92A and 92B are substantially equal (including the case where they are equal). What kind of value this set flow rate (distributed flow rate) should be specifically determined may be appropriately determined by performing a test or the like. The adjustment of the distribution flow rate of air to the catalyst layers 92A and 92B to be the set flow rate is performed by opening control of a flow rate adjusting valve or blower output control in the air supply device. In this case, it may be branched from one air supply device and supplied to the two-stage catalyst layers 92A and 92B, respectively, or may be supplied from the two air supply devices to the two-stage catalyst layers 92A and 92B, respectively. May be. The same applies to the following other embodiments.

Each of the catalyst layers 92A and 92B in each stage is formed by filling the catalyst filling portions 98A and 98B such as cylindrical bodies with an oxidation reforming catalyst. In this case, a catalyst capable of suppressing methanation (no methane is generated) is used as the oxidation reforming catalyst. That is, here, even if DME is used as the reformed fuel, a catalyst that does not generate methane is used as the oxidation reforming catalyst. The reforming reaction formula in this case is as follows. Here, the reactions of the formulas (4), (5), and (6) occur simultaneously, the formula (4) is a reaction that occurs by combining the formulas (7) and (8), and the formula (5) This is a reaction that occurs by combining (7) and formula (9). Here, methane (CH ₄ ) is not generated.
DME + H ₂ O → 2CO + 4H ₂ −Q (4)
DME + 3H ₂ O → 2CO ₂ + 6H ₂ −Q (5)
DME + xO ₂ → (CO + CO ₂ + H ₂ + H ₂ O) + Q (6)
_{DME + H 2 O → 2MeOH -Q} (7)
MeOH → CO + 2H ₂ −Q (8)
MeOH + H ₂ O → CO ₂ + 3H ₂ −Q (9)

In this case, any catalyst may be used as long as it can suppress methanation when steam reforming the reformed fuel. When dimethyl ether is used as a reforming raw material, for example, it is disclosed in Patent Document 3. A dimethyl ether reforming catalyst can be used. Patent Document 1 discloses the following dimethyl ether reforming catalyst.
(1) a solid-type solid acid catalyst (a catalyst containing a solid acid as a main component), one or more metals selected from the group consisting of alkaline earth metals, metals having a melting point higher than the melting point of Cu, and rare earth metals A dimethyl ether reforming catalyst comprising a solid catalyst (a catalyst containing Cu as a main component) containing Cu.
(2) A dimethyl ether reforming catalyst in which a solid type solid acid catalyst containing two or more kinds of solid acids and a solid type catalyst containing at least Cu are dispersed and coordinated.
(3) A dimethyl ether reforming catalyst comprising a solid type solid acid catalyst, and a solid type catalyst comprising Cu and either Zn or Al.
(4) A dimethyl ether reforming catalyst comprising a spinel-structured CuAl ₂ O ₄ crystal.

  The exhaust gas (reformed gas) discharged from the reformer 91 (second stage catalyst layer 92) is then passed through the CO converter 99 and the CO remover 100 in order to reduce the CO concentration.

  The reformer 91 according to the fifth embodiment is provided with a cooler 101 as a cooling means for cooling the downstream end of the second-stage catalyst layer 92B in the gas flow direction. The cooler 101 has a cylindrical shape and is attached to the outer peripheral surface of the downstream end portion of the catalyst filling portion 98 in the gas flow direction. A cooling medium supply line 102 and a cooling medium discharge line 103 are connected to the cooler 101, and the cooling medium supplied from the cooling medium discharge line 102 to the cooler 101 flows through the cooler 101 and then is cooled. It is discharged from the medium discharge line 103. At this time, the downstream end of the catalyst layer 92B in the gas flow direction is cooled by the cooling medium, so that the temperature of the gas at the downstream end decreases to 200 ° C., for example. As a result, the CO concentration in the reformed gas discharged from the reformer 91 (second stage catalyst layer 92B) is reduced to, for example, 2 to 3%.

  The reason for cooling the downstream end portion in the gas flow direction of the second (last) catalyst layer 92B is that if the upstream portion of the reforming catalyst layer 92B is cooled, the steam reforming, which is an endothermic reaction, is performed. This is because it is considered that the steam reforming reaction is completely (or almost) completed at the position of the downstream end portion of the reforming catalyst layer 92B. In addition, what is necessary is just to set suitably about the specific position of the said downstream end part suitable for installing the cooler 101 by a test. This also applies to the following other embodiments.

  The cooler 101 is not limited to the configuration of the illustrated example, and may be any device that can cool the downstream end of the catalyst layer 92B and lower the gas temperature at the downstream end. . For example, the configuration of the cooler 101 may be a configuration in which a tube for circulating a cooling medium is wound around the outer peripheral surface of the downstream end portion of the catalyst filling unit 98. In addition, any cooling medium may be used. For example, it is possible to use a liquid such as raw water before being supplied to the evaporator 93 or cooling water before cooling the fuel cell in terms of cooling capacity. Desirably, air for partial oxidation reaction, air for burner combustion, etc. can also be used. The same applies to the following other embodiments.

  Further, a cooling medium flow rate adjustment valve 106 is installed in the cooling medium supply line 102, and a temperature sensor 104 as temperature control means is installed on the outlet side of the reformer 91 (second stage catalyst layer 92B). ing. The temperature sensor 104 measures the temperature of the exhaust gas (reformed gas) discharged from the second-stage catalyst layer 92 </ b> B and transmits this temperature measurement signal to the temperature control device 105. The temperature control device 105 controls the opening of the cooling medium flow rate adjustment valve 106 so that the temperature measurement value of the temperature sensor 104 becomes a predetermined temperature (for example, 200 ° C.), thereby reducing the supply amount of the cooling medium to the cooler 101. Control. That is, if the measured temperature value is lower than the predetermined temperature, the cooling capacity of the cooler 101 is increased by increasing the amount of the coolant supplied to the cooler 101 by increasing the opening degree of the coolant flow rate adjustment valve 106, while increasing the temperature of the cooler 101. If the measured value is higher than the predetermined temperature, the cooling capacity of the cooler 101 is lowered by decreasing the opening amount of the coolant flow rate adjusting valve 106 and decreasing the amount of coolant supplied to the cooler 101. That is, the temperature control device 105 and the cooling medium flow rate adjustment valve 102 are temperatures for controlling the cooling capacity of the cooler 101 (cooling means) so that the temperature measurement value of the temperature sensor 104 (temperature measuring means) becomes a predetermined temperature. It constitutes a control means.

  From the above, according to the reformer of the fifth embodiment, the same effects as those of the first embodiment can be obtained, and the gas flow direction in the second (last) catalyst layer 92B is obtained. In order to cool the downstream end portion of the catalyst layer 92 by the cooler 101, the gas temperature at the downstream end portion of the catalyst layer 92B decreases, and from the equilibrium reaction, the CO concentration in the reformed gas at the outlet of the catalyst layer 92B is Reduce. Therefore, after that, when the reformed gas is sequentially passed through the CO converter (LTS) 99 and the CO remover 100 to reduce CO, the CO shifter 99 reduces the amount of CO shift reaction of the reformed gas. By reducing the amount of heat generated by the reaction, it is possible to bring the CO concentration in the reformed gas closer to an equilibrium state even if the amount of the low-temperature CO shift catalyst is small, and reforming at the CO converter 99 outlet is performed. The CO concentration in the gas can be reduced. This also makes it possible to reduce the amount of air for the CO selective oxidation reaction in the CO remover, and to reduce the number of stages of the CO remover.

  The reason why the CO concentration in the reformed gas at the outlet of the catalyst layer 92B is reduced will be described with reference to FIG. 12. If the reformed gas is cooled by a cooler provided at the subsequent stage of the catalyst layer 92B, As shown in FIG. 12a, the temperature of the reformed gas only decreases to 200 ° C., and the CO concentration in the reformed gas remains high without decreasing. On the other hand, when the reformed gas is cooled at the downstream end of the catalyst layer 92B, that is, when the gas is cooled at a position where the reforming catalyst is present, the lower the temperature of the reformed gas, Since the CO concentration in the equilibrium state becomes low as in c, the CO concentration in the reformed gas at the outlet of the catalyst layer 92B also decreases as shown in b of FIG. The reason why the CO concentration does not decrease to the equilibrium concentration is that a sufficient amount of catalyst cannot be provided due to the limitation of the installation space as described above, and the gas is not contained in the catalyst layer compared to the time until the equilibrium state is reached. This is because the time passing through 92B is shorter.

  Further, according to the reformer of the fifth embodiment, the temperature of the exhaust gas (reformed gas) discharged from the second stage (last stage) catalyst layer 92B is measured, and this temperature measurement value is predetermined. Since the cooling capacity of the cooler 101 is controlled so as to reach the temperature, the gas temperature at the downstream end of the catalyst layer 92B can be reliably lowered to the predetermined temperature. For this reason, said effect can be exhibited reliably.

Further, according to the reformer of the fifth embodiment, since a catalyst capable of suppressing methanation is used as a catalyst for promoting the partial oxidation reaction of fuel and the steam reforming reaction of fuel, for example, dimethyl ether is used as the fuel. Even if it is used, when the downstream end of the catalyst layer 92B is cooled by the cooler 101 to reduce the gas temperature, it is possible to prevent the generation of methane from being promoted to increase the methane concentration. Explaining based on FIG. 13, when a catalyst capable of suppressing methanation is not used, if the gas is cooled at a certain position of the reforming catalyst, the reaction from the left to the right is promoted for the reaction of the following formula (11). While the CO concentration decreases as shown in FIG. 13d, the reaction of formula (10) is promoted from right to left, that is, the reaction in which CH ₄ is generated, and the CH ₄ concentration as shown in FIG. 13e. Will increase. On the other hand, if a catalyst capable of suppressing methanation is used, an increase in CH ₄ concentration can be prevented and only a CO concentration can be reduced.
_{CH 4 + H 2 O ⇔ CO} + 3H 2 -Q (10)
CO + H ₂ O⇔CO ₂ + H ₂ + Q (11)

  In the reformer 91, the number of catalyst layers is two. However, the number of catalyst layers is not limited to this, and in the fifth embodiment, as in the first embodiment, three stages are used. It is good also as the above catalyst layer. In this case, what is necessary is just to cool the downstream side edge part of the gas distribution direction of the catalyst layer of the last stage with a cooler.

<Embodiment 6>
FIG. 14 (a) is a longitudinal sectional view showing the configuration of a reformer according to Embodiment 6 of the present invention, FIG. 14 (b) is a sectional view taken along line GG in FIG. 14 (a), and FIG. (A) is a longitudinal cross-sectional view which shows the other structure of the modifier based on Embodiment 6 of this invention, FIG.15 (b) is a HH arrow directional cross-sectional view of Fig.15 (a).

  14 and 15 show the reformer 21 having the same configuration as that of FIG. 2 provided with coolers 201 and 301, respectively. Therefore, the coolers 201 and 301 will be described here, and the description of the configuration will be omitted.

  In FIG. 14, a cylindrical cooler 201 is mounted on the outer peripheral surface of the downstream end of the cylindrical body 23 in the gas flow direction. A cooling medium supply line 202 and a cooling medium discharge line 203 are connected to the cooler 201, and the cooling medium supplied from the cooling medium discharge line 202 to the cooler 201 flows through the cooler 201 and then is cooled. It is discharged from the medium discharge line 203. At this time, the downstream end of the gas flow direction in the second-stage catalyst layer 25B is cooled by the cooling medium, so that the gas temperature at the downstream end decreases to, for example, 200 ° C. As a result, the CO concentration in the reformed gas discharged from the reformer 21 (second stage catalyst layer 25B) is reduced to, for example, 2 to 3%.

  In FIG. 15, a cylindrical cooler 301 is mounted on the downstream end in the gas flow direction on the inner peripheral side of the second-stage catalyst layer 25B. The cooler 301 has a double-structured cooling medium flow path composed of an outer flow path 305 and an inner flow path 306 formed by triple cylinders 302, 303, and 304. A cooling medium supply line 307 is connected, and a cooling medium discharge line 308 is connected to the inner flow path 306. A gap between the end surface 309 of the cylindrical body 302, the cylindrical body 303, and the tip serves as a folded portion 310. Therefore, the cooling medium supplied to the cooler 301 from the cooling medium discharge line 307 flows into the outer flow path 305 and flows through the outer flow path 305, then turns back at the turn-back portion 310 and flows into the inner flow path 306, The refrigerant flows through the inner flow path 306 and is discharged from the cooling medium discharge line 308. At this time, the downstream end of the gas flow direction in the second-stage catalyst layer 25B is cooled by the cooling medium, so that the gas temperature at the downstream end decreases to, for example, 200 ° C. As a result, the CO concentration in the reformed gas discharged from the reformer 21 (second stage catalyst layer 25B) is reduced to, for example, 2 to 3%.

  Even in the case of having three or more catalyst layers, a cooler (cooling means) is provided at the downstream end in the gas flow direction of the outermost cylindrical body (cylindrical body 34 in the example of FIG. 6). What is necessary is just to comprise so that the downstream edge part of the gas distribution direction in the catalyst layer of a step (outermost side) may be cooled. For example, in the reformer 36 of FIG. 6, the downstream end of the third catalyst layer 25C in the gas flow direction may be cooled by a cooler.

  Also in the sixth embodiment, it is desirable to use, for example, DME as the reformed fuel, or to use a catalyst capable of suppressing methanation as the oxidation reforming catalyst of the catalyst layers 25A and 25B in each stage. This is the same as the fifth embodiment. Although illustration and detailed description are omitted, in the sixth embodiment, the same gas temperature control as in the fifth embodiment (FIG. 11) can be performed.

  From the above, according to the reformer 21 of the sixth embodiment, in addition to obtaining the same effects as those of the second embodiment, the second-stage catalyst layer is used in the coolers 201 and 301. Since the downstream end of the gas flow direction of 25B is cooled, the same effect as in the fifth embodiment can be obtained.

<Embodiment 7>
FIG. 16 (a) is a longitudinal sectional view showing the configuration of the reformer according to Embodiment 7 of the present invention, and FIG. 16 (b) is a sectional view taken along the line II in FIG. 16 (a).

  As shown in FIGS. 16 (a) and 16 (b), the reformer 401 of the seventh embodiment obtains a hydrogen-containing gas (reformed gas) by a steam reforming reaction of fuel, and has a diameter. The catalyst container 405 has a triple cylindrical structure in which four different cylindrical bodies 402, 403, and 404 are stacked. The reformer 401 includes an inner cylindrical body 402 (catalyst filling portion) filled with an oxidation reforming catalyst, a catalyst layer 406A, and an intermediate cylindrical body 403 and an outer cylindrical body 404 (catalyst filling). Part) has a two-stage catalyst layer structure composed of a catalyst layer 406B filled with an oxidation reforming catalyst, and the inner side (first stage) as shown by the arrows in FIG. The gas is flowed sequentially from the catalyst layer 406A to the catalyst layer 406B on the outside (second stage) with the gas flow directions of the catalyst layers 406A and 406B at the respective stages reversed (turned back). . That is, in the first stage catalyst layer 406A, the gas flows in the left direction as shown by the arrow, and in the second stage catalyst layer 406B, the gas flows back as shown by the arrow and flows in the right direction in the figure.

  Between the first catalyst layer 406A and the second catalyst layer 406B, there is formed a double-structured gas channel including an inner gas channel 408 and an outer gas channel 407. As shown by the arrows in FIG. 16, the mixed gas flows back and forth through the inner gas flow path 408 and the outer gas flow path 407, and then mixed with air (oxidizing gas) in the mixing section 420 to be the first catalyst layer. It is configured to be supplied to 406A.

  More specifically, a cylindrical body 417 is provided between the cylindrical body 402 and the cylindrical body 403, and a gap between the cylindrical body 402 and the cylindrical body 403 is defined as an inner gas flow path 408, and the cylindrical body 403 and the cylindrical body. A gap between 417 and the outer gas flow path 407 is formed. In addition, a gap between the tip of the cylindrical body 417 and the end face 43 on the right side of the cylindrical body 403 in the figure is a folded portion 436. One end of a mixed gas pipe 419 is connected to the left end surface 435 of the cylindrical body 404 in the drawing, and the other end of the mixed gas pipe 419 is connected to the mixed gas supply unit 423. A leading end of an air distribution pipe 414 is inserted into one end of the mixed gas pipe 419, and this part serves as a mixing section 420. The tip of the air distribution pipe 414 is closed by an end surface 442, and a plurality of outlets 429 are formed in the circumferential direction of the side surface of the tip. A gap 445 is secured between the air distribution pipe 414, the tip, and one end of the mixed gas pipe 419.

  A throttle 425 is provided in the middle of the mixed gas pipe 419. The mixed gas supply unit 423 has a cylindrical shape and penetrates the end surface 413 (end surface 435 and the end surface 415) of the cylindrical body 417 and the end surface 415 of the cylindrical body 402. It is located in the space part 438 ensured between 413 and 413. A plurality of outlets 424 are formed in the circumferential direction at the tip of the mixed gas supply unit 423. The end of the mixed gas supply pipe 412 is connected to the end surface 413 of the cylindrical body 417. A space portion 440 is secured between the end surface 413 of the cylindrical body 417 and the end surface 415 of the cylindrical body 402, and a space portion is defined between the outer end surface 420 of the cylindrical body 404 and the inner end surface 434 of the cylindrical body 404. 441 is secured. A space 439 is secured between one end of the second-stage catalyst layer 406 </ b> B and the inner end surface 434 of the cylindrical body 404. A base end of a gas exhaust pipe 418 is connected to an end surface 434 on the inner side of the cylindrical body 404.

  An air distribution pipe 416 is inserted through the first stage catalyst layer 406 </ b> A and the mixed gas supply unit 423. The tip of the air distribution pipe 416 protrudes from the other end of the catalyst layer 406, and a plurality of outlets 426 are formed in the circumferential direction of the side surface. The tip of the air distribution pipe 416 is closed by the end face 411. The front end portion of the air distribution pipe 416 and the cylindrical body 412 surrounding the front end portion constitute a mixing portion 421. A gap is secured between one end of the cylindrical body 412 and the other end of the catalyst layer 406 </ b> A, and this gap serves as an outlet 427. A gap 446 is secured between the cylindrical tube 412 and the tip of the air distribution pipe 416. The other end of the cylindrical body 412 is connected to the inner periphery of the left end face 410 (the same face as the end face 433) of the cylindrical tube 402, and a space portion is provided between the end face 410 and the other end of the catalyst layer 406A. 437 is secured. A space 444 is secured between the left end surface 409 of the cylindrical body 404 and the other end of the catalyst layer 406B. Further, a gap 443 is secured between the end face 409 of the cylindrical body 404 and the end faces 410 and 433 of the cylindrical bodies 402 and 403, and the gap 446 and the space portion 444 communicate with each other through the gap 443.

  The gas flow will be described. A mixed gas of fuel (DME) and water vapor sent from a mixed gas supply device (not shown) flows into the space 440 through the mixed gas supply pipe 412 and then the inner gas flow path 408. Flow into. The mixed gas that has flowed into the inner gas flow path 408 flows through the inner gas flow path 408, and then is folded at the turn-back portion 436 to flow through the outer gas flow path 407. Note that the mixed gas pipe 419 and the mixed gas supply pipe 412 may be reversely connected so that the mixed gas first flows through the outer gas channel 407 and then flows through the inner gas channel 408. That is, the mixed gas may reciprocate between the inner gas channel 408 and the outer gas channel 407. During this time, the reformed gas is preheated by heat exchange with the catalyst layers 406A and 406B.

  The mixed gas discharged from the outer gas flow path 407 to the space portion 441 (in the reverse case, from the inner gas flow path 408 to the space portion 440) flows through the gap 445. Air (oxidizing gas) supplied from an air supply device (not shown) through the air supply pipe 414 is blown out from the outlet 429 and mixed with the mixed gas. After that, the mixed gas of fuel, water vapor, and air is squeezed by the throttle unit 425 while being mixed through the mixed gas pipe 419 and further mixed, and then flows into the mixed gas supply unit 423 and blown out from the outlet 424. Into one end of the first catalyst layer 406A.

  A part of the mixed gas flowing into the catalyst layer 406A is steam-reformed while flowing through the catalyst layer 406A to become a hydrogen-containing gas (reformed gas), and is discharged from the other end of the catalyst layer 406A to the space portion 437. The exhaust gas is blown out from the blowout port 427 and flows through the gap 446. On the other hand, air (oxidizing gas) from the air supply device is introduced into the other end side of the catalyst layer 406A through the air distribution pipe 416, and then blown out from the blowout port 426 and discharged through the gap 446. Mixed with gas. Thereafter, the mixed gas flows into the other end of the second-stage catalyst layer 406B through the gap 443 and the space 444. The mixed gas flowing into the catalyst layer 406B is further steam-reformed while flowing through the catalyst layer 406B to become a hydrogen-containing gas (reformed gas), and is discharged from the other end of the catalyst layer 406B to the space portion 438. Exhaust gas (reformed gas) discharged into the space 438 is discharged through a gas discharge pipe 418.

  Also in the seventh embodiment, the cylindrical cooler 430 is mounted on the outer peripheral surface of the downstream end portion of the cylindrical body 404 in the gas flow direction. A cooling medium supply line 431 and a cooling medium discharge line 432 are connected to the cooler 430, and the cooling medium supplied from the cooling medium discharge line 431 to the cooler 430 flows through the cooler 430 and is then cooled. It is discharged from the medium discharge line 432. At this time, the downstream end of the second-stage catalyst layer 406B in the gas flow direction is cooled by the cooling medium, so that the gas temperature at the downstream end decreases to, for example, 200 ° C. As a result, the CO concentration in the reformed gas discharged from the reformer 401 (second stage catalyst layer 406B) is reduced to, for example, 2 to 3%.

  In Embodiment 7 as well, it is desirable to use, for example, DME as the reformed fuel, or to use a catalyst capable of suppressing methanation as the oxidation reforming catalyst of the catalyst layers 406A and 406B at each stage. This is the same as the fifth embodiment. Although illustration and detailed description are omitted, the same gas temperature control as in the fifth embodiment (FIG. 11) can be performed in the seventh embodiment. Further, the distribution flow rate of air to the two catalyst layers 406A and 406B is the same as that in the first embodiment. That is, the flow rate of air distributed to the two-stage catalyst layers 406A and 406B is set to a flow rate at which the peak temperatures of the two-stage catalyst layers 406A and 406B are substantially equal (including the case where they are equal).

  As described above, according to the reformer 401 of the seventh embodiment, the same effect as that of the second embodiment can be obtained, and in addition, the second stage catalyst layer 406B can be formed by the cooler 43. Since the downstream end in the gas flow direction is cooled, the same effect as in the fifth embodiment can be obtained.

  Further, according to the reformer 401 of the seventh embodiment, the inner gas passage 408 and the outer gas passage 407 are provided between the first catalyst layer 406A and the second catalyst layer 406B. A double-structure gas flow path is formed, and the mixed gas flows back and forth through the inner gas flow path 408 and the outer gas flow path 407, and then mixed with air and supplied to the first-stage catalyst layer 406A. Due to the configuration, the mixed gas is preheated by heat exchange with the first and second catalyst layers 406A and 406B while flowing through the double-structure gas flow path, and then enters the first catalyst layer 406A. Since it flows in, the steam reforming reaction occurs near the inlet of the first stage catalyst layer 406A, and the reforming efficiency is improved. Furthermore, the effect of reducing the peak temperatures of the first and second catalyst layers 406A and 406B can be obtained by the heat exchange.

  Here, application examples of the reformer of the present invention will be described. The reformer of the present invention can be applied to various apparatuses that require hydrogen. Here, examples of application to a fuel cell power generation system and a hydrogen station will be described. FIG. 17 is a schematic diagram of a fuel cell power generation system, and FIG. 18 is a schematic diagram of a hydrogen station.

  As shown in FIG. 17, the reformer 75 of the fuel cell power generation system includes any one of the desulfurizer 71 and the reformer 1 (or the reformers 21, 36, 51, 61, 91, 401 of the above embodiment). Or: hereinafter referred to as the reformer 1), a CO converter 72, and a CO remover 73. The reformed gas (hydrogen-containing gas) generated here is in a solid polymer form. Or the like to the fuel cell 74. The desulfurizer 71 removes sulfur contained in the fuel. In the reformer 1 and the like, a hydrogen-containing gas is generated by the partial oxidation reaction and the steam reforming reaction based on the mixed gas of the fuel and the steam from which the sulfur content has been removed and the air. The CO converter 72 has a catalyst layer filled with a catalyst for promoting the shift reaction, and CO contained in the hydrogen-containing gas generated in the reformer 1 and the like is oxidized by the shift reaction. Further, the CO remover 73 removes CO remaining in the hydrogen-containing gas discharged from the CO converter 72 to reduce the CO concentration. For example, in a CO remover having a catalyst layer filled with a catalyst that promotes a selective oxidation reaction, CO contained in the hydrogen-containing gas is oxidized by a selective oxidation reaction. Thus, a hydrogen-containing gas having a very low CO concentration is obtained, and this hydrogen-containing gas is supplied to the fuel cell 74.

  As shown in FIG. 18, in the case of using hydrogen at the hydrogen station 85, the hydrogen generated by the partial oxidation reaction and the steam reforming reaction in the reformer 1 or the like based on the mixed gas of fuel and steam and air. Hydrogen is extracted from the contained gas by the hydrogen purification means 81. Examples of the hydrogen purification method applied in the hydrogen purification means 81 include an absorption method, a cryogenic separation method, an adsorption method, and a membrane separation method. The membrane separation method is a purification method that utilizes the difference in the speed of gas components that permeate the separation membrane. In particular, a combination of a reformer and a metal-based separation membrane (hydrogen permeable membrane) is called a membrane reactor. Hydrogen taken out by the hydrogen purification means 81 is stored in the storage tank 82 of the hydrogen station 85. Then, the hydrogen stored in the storage tank 82 is supplied to the vehicle 84 from the hydrogen supply device 83 of the hydrogen station 85.

  The present invention relates to a reforming method and a reformer, and is useful when applied to, for example, a reformer of a fuel cell power generation system or a hydrogen supply source (membrane reactor or the like) to a hydrogen station.

It is a block diagram of the reformer (reforming method) according to Embodiment 1 of the present invention. (A) is a longitudinal cross-sectional view which shows the structure of the reformer which concerns on Embodiment 2 of this invention, (b) is an AA arrow directional cross-sectional view of (a). (A) is a figure which shows the other structural example of a mixing part, (b) is a principal part perspective view of (a). It is a figure which shows the other structural example of a mixing part. It is a figure which shows the temperature distribution of the catalyst layer of the said reformer. (A) is a longitudinal cross-sectional view which shows the other structure of the modifier based on Embodiment 2 of this invention, (b) is a BB sectional view taken on the line of (a). (A) is a longitudinal cross-sectional view which shows the structure of the reformer which concerns on Embodiment 3 of this invention, (b) is CC sectional view taken on the line of (a). It is a figure which shows the temperature distribution of the catalyst layer of the said reformer. FIG. 9B is a cross-sectional view taken along line DD in FIG. (A) is the longitudinal cross-sectional view which shows the structure of the reformer which concerns on Embodiment 4 of this invention, (b) is the EE arrow directional cross-sectional view of (a), (c) is (a). It is FF arrow directional cross-sectional view. It is a block diagram of the reformer (reforming method) according to Embodiment 5 of the present invention. It is a graph which shows the relationship between gas temperature and CO concentration. It is a graph showing the relationship between the gas temperature and the CO concentration and CH ₄ concentration. (A) is a longitudinal cross-sectional view which shows the structure of the reformer which concerns on Embodiment 6 of this invention, (b) is a GG arrow directional cross-sectional view of (a). (A) is a longitudinal cross-sectional view which shows the other structure of the modifier based on Embodiment 6 of this invention, (b) is a HH arrow directional cross-sectional view of (a). (A) is a longitudinal cross-sectional view which shows the structure of the reformer which concerns on Embodiment 7 of this invention, (b) is the II sectional view taken on the line of (a). It is a schematic diagram of a fuel quantity battery power generation system. It is a schematic diagram of a hydrogen station. It is a schematic block diagram of the conventional reformer. It is a schematic block diagram of the other conventional reformer. It is a graph which shows the temperature distribution of a catalyst layer.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Reformer 12A, 12B Catalyst layer 13A, 13B Catalyst filling part 14,15 Mixer 21 Reformer 22 Cylindrical body 22a, 22b End surface 23 Cylindrical body 23a, 23b End surface 24 Catalyst container 25A, 25B Catalyst layer 26 Inlet part 27 Mixer 28 Mixing part 29 Air distribution pipe 29a Tip part 29b End face 29c Blowing outlet 30 Exhaust gas outlet flow path 31 Baffle plate 31a Notch part 32 Space part (flow path part)
33 Outlet portion 34 Cylindrical body 34a, 34b End face 35 Catalyst container 36 Reformer 37 Mixer 38 Inlet portion 51 Reformer 52, 53 Heat transfer fin 61 Reformer 62, 63 Heat transfer fin 71 Desulfurizer 72 CO converter 73 CO remover 74 Fuel cell 81 Purification device 82 Storage tank 83 Hydrogen supply device 84 Vehicle 85 Hydrogen station 91 Reformer 92A, 92B Catalyst layer 93 Evaporator 94 Burner 95 Burner outer tube 96 Tube 97 Mixer 98A, 98B Catalyst filling Part 99 CO converter 100 CO remover 101 Cooler 102 Cooling medium supply line 103 Cooling medium discharge line 104 Temperature sensor 105 Temperature controller 106 Cooling medium flow control valve 107 Mixer 201 Cooler 202 Cooling medium supply line 203 Cooling medium discharge Line 301 Cooler 302, 3 03,304 Cylindrical body 305 Outer flow path 306 Inner flow path 307 Cooling medium supply line 308 Cooling medium discharge line 309 End face 310 Folded portion 401 Reformer 402, 403, 404 Cylindrical body 405 Catalyst container 406A, 406B Catalyst layer 407 Outer gas Flow path 408 Inner gas flow path 409, 410, 411 End face 412 Mixed gas supply pipe 413 End face 414 Air supply pipe 415 End face 416 Air distribution pipe 417 Cylindrical body 418 Gas discharge pipe 419 Mixed gas pipe 420 Mixing section 421 Mixing section 423 Mixed gas Supply part 424 Outlet 425 Restriction part 426,427 Outlet 429 Outlet 430 Cooler 431 Cooling medium supply line 432 Cooling medium discharge line 433, 434, 435 End face 436 Folded parts 437, 438, 439, 440, 41 space 442 end face 443 a gap 444 space 445, 446 gap

Claims (20)

In a reforming method for obtaining a hydrogen-containing gas by a steam reforming reaction of fuel,
A plurality of catalyst layers formed by filling a catalyst filling portion with a catalyst that promotes the partial oxidation reaction of the fuel and the steam reforming reaction of the fuel are connected in series, from the previous catalyst layer to the subsequent catalyst layer. And let gas flow in sequence,
The mixed gas of fuel and water vapor is supplied to the first catalyst layer of the plurality of catalyst layers, while the oxidizing gas is distributed to each of the plurality of catalyst layers, and the first catalyst layer Is supplied with the mixed gas after being mixed with the mixed gas, and is supplied with the exhaust gas after being mixed with the exhaust gas discharged from the catalyst layer in the preceding stage of the catalyst layer to the catalyst layer of the other stage. A characteristic modification method. The reforming method according to claim 1,
A reforming method characterized in that the flow rate of the oxidizing gas distributed to each of the plurality of catalyst layers is set to a flow rate at which peak temperatures of the catalyst layers of the plurality of stages are substantially equal. In a reformer configured to obtain a hydrogen-containing gas by a steam reforming reaction of fuel,
A plurality of catalyst layers formed by filling a catalyst filling portion with a catalyst that promotes the partial oxidation reaction of the fuel and the steam reforming reaction of the fuel are connected in series, from the previous catalyst layer to the subsequent catalyst layer. And the gas flow in sequence,
The mixed gas of fuel and water vapor is supplied to the first catalyst layer of the plurality of catalyst layers, while the oxidizing gas is distributed to each of the plurality of catalyst layers, and the first catalyst layer Is mixed with the mixed gas by the mixing means and then supplied together with the mixed gas, and the other catalyst layer is mixed with the exhaust gas discharged from the previous catalyst layer of the catalyst layer by the other mixing means. A reformer characterized in that the reformer is supplied together with the exhaust gas. The reformer according to claim 3, wherein
The reformer characterized in that the flow rate of the oxidizing gas distributed to each catalyst layer of the plurality of stages is set to a flow rate at which the peak temperatures of the catalyst layers of the plurality of stages are substantially equal. In a reformer configured to obtain a hydrogen-containing gas by a steam reforming reaction of fuel,
It has a catalyst container with a multiple cylinder structure in which a plurality of cylinders are stacked,
A catalyst layer formed by filling a catalyst for promoting a partial oxidation reaction of the fuel and a catalyst for promoting a steam reforming reaction of the fuel into an innermost cylinder of the plurality of cylinders; A multi-stage catalyst layer structure comprising a catalyst for promoting the partial oxidation reaction of the fuel and another catalyst layer filled with a catalyst for promoting the steam reforming reaction of the fuel, and The configuration is such that the gas is sequentially circulated from the inner catalyst layer to the outer catalyst layer by reversing the gas flow direction of each stage catalyst layer,
The mixed gas of fuel and water vapor is supplied to the innermost first catalyst layer of the plurality of catalyst layers, while the oxidizing gas is distributed to each of the plurality of catalyst layers so that the first step The catalyst layer is mixed with the mixed gas by the mixing means and then supplied together with the mixed gas, and the other catalyst layer is supplied with the exhaust gas discharged from the previous catalyst layer of the catalyst layer and the other mixing means. A reformer characterized by being configured to supply together with the exhaust gas after mixing. In a reformer configured to obtain a hydrogen-containing gas by a steam reforming reaction of fuel,
It has a catalyst container with a multiple cylinder structure in which a plurality of cylinders are stacked,
A catalyst layer formed by filling a catalyst for promoting a partial oxidation reaction of the fuel and a steam reforming reaction of the fuel into an innermost cylinder of the plurality of cylinders; and A multi-stage catalyst layer structure comprising a catalyst layer that is filled with a catalyst that promotes a partial oxidation reaction of the fuel and a steam reforming reaction of the fuel, and an outer side from the inner catalyst layer. To the catalyst layer, the gas flow direction of each stage of the catalyst layer is reversed, and the gas is sequentially flowed,
The mixed gas of fuel and water vapor is supplied to the innermost first catalyst layer of the plurality of catalyst layers, while the oxidizing gas is distributed to each of the plurality of catalyst layers so that the first step The catalyst layer is mixed with the mixed gas by the mixing means and then supplied together with the mixed gas, and the other catalyst layer is supplied with the exhaust gas discharged from the previous catalyst layer of the catalyst layer and the other mixing means. A reformer characterized by being configured to supply together with the exhaust gas after mixing. The reformer according to claim 5 or 6,
The reforming is characterized in that the oxidizing gas distributed to the second catalyst layer of the plurality of catalyst layers is distributed by an oxidizing gas distribution pipe inserted into the first catalyst layer. vessel. The reformer according to claim 7, wherein
The mixing means for mixing the exhaust gas from the first stage catalyst layer and the oxidizing gas distributed to the second stage catalyst layer is such that the downstream end of the innermost cylinder is narrower than the catalyst layer portion. A reformer characterized in that the downstream end of the oxidizing gas distribution pipe is positioned inside the exhaust gas outlet flow path. The reformer according to claim 8, wherein
In the exhaust gas outlet channel, a plurality of baffle plates having a notch portion serving as a gas channel portion on the outer peripheral portion are arranged in series such that the circumferential positions of the notch portions of adjacent baffle plates are different from each other. A reformer characterized in that the reformer is disposed. The reformer according to claim 8 or 9,
The reformer characterized in that the oxidizing gas distribution pipe has a structure in which a downstream end face is closed and an oxidizing gas outlet is formed on the side face of the downstream end. The reformer according to any one of claims 5 to 10,
A reformer characterized in that a plurality of heat transfer fins are disposed in each of the catalyst layers of the plurality of stages. The reformer of claim 11, wherein
The reformer according to claim 1, wherein the heat transfer fin is disposed only in an upstream portion of the catalyst layers of the plurality of stages. The reformer according to any one of claims 5 to 12,
The reformer characterized in that the flow rate of the oxidizing gas distributed to each catalyst layer of the plurality of stages is set to a flow rate at which the peak temperatures of the catalyst layers of the plurality of stages are substantially equal. The reforming method according to claim 1 or 2,
A reforming method, wherein a downstream end portion in the gas flow direction in the last catalyst layer of the plurality of catalyst layers is cooled by a cooling means. The reforming method according to claim 14, wherein
A reforming method characterized in that the temperature of exhaust gas discharged from the last catalyst layer is measured, and the cooling capacity of the cooling means is controlled so that the measured temperature value becomes a predetermined temperature. The modification method according to claim 14 or 15,
A reforming method using a catalyst capable of suppressing methanation as a catalyst for promoting the partial oxidation reaction of the fuel and the steam reforming reaction of the fuel. The reformer according to any one of claims 5 to 13, wherein
Forming a double-structure gas flow path comprising an inner gas flow path and an outer gas flow path between the first catalyst layer and the second catalyst layer of the plurality of catalyst layers;
The reformed gas is configured such that the mixed gas flows back and forth between the inner gas channel and the outer gas channel, and then is mixed with the oxidizing gas and supplied to the first catalyst layer. vessel. The reformer according to any one of claims 3 to 13, and 17,
A reformer comprising cooling means for cooling the downstream end portion in the gas flow direction of the last catalyst layer of the plurality of catalyst layers. The reformer of claim 18, wherein
Temperature measuring means for measuring the temperature of the exhaust gas discharged from the final stage catalyst layer;
A reformer comprising temperature control means for controlling the cooling capacity of the cooling means so that the temperature measurement value of the temperature measuring means becomes a predetermined temperature. The reformer according to claim 18 or 19,
The reformer characterized in that the catalyst that promotes the partial oxidation reaction of the fuel and the steam reforming reaction of the fuel is a catalyst that can suppress methanation.

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