JP4413040B2 - Shift reactor - Google Patents

Description

  The present invention relates to a shift reaction apparatus used for converting and removing carbon monoxide (CO) contained in a hydrogen-rich reformed gas by an aqueous shift reaction.

  In recent years, attention has been focused on fuel cells. This fuel cell converts chemical energy possessed by city gas, gasoline, etc. into electric energy, and produces hydrogen as fuel for power generation from raw fuel such as kerosene through several catalytic reactions. A manufacturing device is provided. In this hydrogen production apparatus, a sulfur compound is desulfurized from a fuel made of kerosene through a catalyst of a desulfurizer. Next, by adding water to the desulfurized fuel and passing the fuel through a reformer catalyst, the fuel is decomposed into a reformed gas composed of hydrogen, carbon monoxide, carbon dioxide, and a small amount of methane. . Next, this reformed gas is passed through the catalyst of the shift reactor, so that most of the carbon monoxide is converted into carbon dioxide and hydrogen by an aqueous shift reaction. Finally, the reformed gas is passed through the catalyst of the CO selective oxidizer to oxidize harmful carbon monoxide to carbon dioxide and supply the hydrogen-rich reformed gas from which carbon monoxide has been removed to the fuel cell stack. Like to do.

  Here, as a shift reaction apparatus constituting a part of such a hydrogen production apparatus, for example, the one shown in Patent Document 1 has been proposed. As shown in FIG. 8, this shift reaction apparatus includes a cylindrical container 100 provided with an inlet 100A and an outlet 100B at both ends in the axial direction, and a cylindrical container accommodated concentrically in the container 100. The catalyst layer 101 and the plate 102 which close | closes the opening end located in the delivery port 100B side among the catalyst layers 101 are provided.

In this shift reaction apparatus, the reformed gas supplied from the reformer is guided to the inner peripheral side of the catalyst layer 101 from the inlet 100A. Here, since the opening end located on the delivery side 100B of the catalyst layer 101 is closed by the plate 102, the raw fuel passes through the inside of the catalyst layer 101 and then toward the outer peripheral side of the catalyst layer 101. As a result, while the reformed gas passes through the inside of the catalyst layer 101, carbon monoxide is converted into carbon dioxide and hydrogen and sent out from the outlet 100B.
JP-A-11-139802 (paragraph 0033, FIG. 1)

  By the way, according to the shift reaction apparatus described in Patent Document 1, since one open end of the catalyst layer 101 is closed by the plate 102, the reformed gas introduced into the inner peripheral side of the catalyst layer 101 is The catalyst layer 101 is forcibly passed from the inner peripheral side to the outer peripheral side to improve the conversion efficiency of the reformed gas by the catalyst layer 101.

  However, even if such a shift reaction device described in Patent Document 1 is used, the reformed gas cannot always be forced to pass through the raw fuel through the entire catalyst layer 101, and the entire catalyst layer 101 is effectively used. There is a problem that it cannot be used.

  In view of the above problems, an object of the present invention is to provide a shift reaction apparatus in which reformed gas is uniformly fed into the entire catalyst layer so that the entire catalyst layer can be used effectively.

The present invention is configured to solve the above problems, and the invention according to claim 1 is an upstream side between the reaction vessel and one side of the reaction vessel filled in the reaction vessel. A catalyst layer that forms a space, and the reaction vessel is arranged in a vertical direction, the upstream space is formed on one side in the vertical direction in the reaction vessel, and the upper and lower sides in the reaction vessel A downstream space is provided between the other side of the direction and the catalyst layer, and passes through the downstream space from the other side of the reaction vessel to penetrate from the downstream side to the upstream side of the catalyst layer. And a reformed gas supply pipe that opens into the upstream space as a reformed gas supply port for supplying a reformed gas into the upstream space at the front end side, and a reformer provided on the other side of the reaction vessel. and a quality gas outlet, the reforming is provided a plurality of the gas supply pipe, the reformed gas supply A shift reactor, characterized in that provided that they are spaced from each tube.

  According to the shift reaction apparatus of claim 1, the flow of the reformed gas flowing through the reformed gas supply pipe and the flow of the reformed gas flowing through the catalyst layer in the reaction vessel are opposed to each other. be able to. Therefore, for example, the catalyst layer in the reaction vessel can be heated by heat radiation from the reformed gas having an appropriate temperature of about 220 ° C., and can be raised in a short time to a temperature suitable for the reaction by the catalyst layer. For this reason, the startup heating of the catalyst layer can be performed satisfactorily.

According to the shift reactor of claim 1 , by arranging a plurality of reformed gas supply pipes separated from each other, the startup heating of the catalyst layer by the reformed gas supply pipe can be made uniform, Uneven heating can be prevented.

Further , according to the shift reaction apparatus of claim 1 , after the operation of the shift reaction apparatus is stopped (after the supply of the reformed gas is stopped), the condensing component due to the reformed gas or water vapor staying in the reaction vessel is the catalyst. It can accumulate in the space part between a layer and the lower part of reaction container, and can prevent deterioration of the catalyst layer by a condensed component.

The invention according to claim 2 is the shift reaction apparatus according to claim 1 , wherein the reformed gas supply pipe is provided with an air inlet for mixing air with the reformed gas.

According to the shift reaction apparatus of claim 2 , by mixing a small amount of air introduced from the air inlet into the reformed gas and circulating the reformed gas supply pipe, the air and the reformed gas are mixed. The start-up time of the catalyst layer can be shortened by reacting with the contained hydrogen (H2) and generating heat.

According to a third aspect of the present invention, on the outer peripheral surface of the reaction vessel, a heat insulating material is provided on the upstream side of the reformed gas flowing inside the catalyst layer, and a heat insulating material is provided on the downstream side. a shift reactor of claim 1 or claim 2, characterized in that there is no.

According to the shift reaction apparatus of claim 3 , a heat insulating material is provided in a portion of the reaction vessel located upstream of the reformed gas flowing inside the catalyst layer (hereinafter referred to as upstream of the catalyst layer). It is possible to increase the reaction rate by keeping the upstream side of the catalyst layer at a relatively high temperature (for example, about 300 ° C.). On the other hand, since no heat insulating material is provided on the downstream side of the catalyst layer, the carbon monoxide concentration can be kept low by chemical equilibrium while keeping the downstream side of the catalyst layer at a relatively low temperature (for example, 200 ° C.).

The invention according to claim 4 is characterized in that the reformed gas from the reformed gas supply port passes through the axial center portion and the outer peripheral portion of the catalyst layer alternately and is discharged from the reformed gas discharge port. The shift reaction apparatus according to any one of claims 1 to 5, wherein a plurality of rectifying plates for controlling the flow direction of the reformed gas are embedded in the layer.

According to the shift reaction device of claim 4 , the reformed gas supplied into the upstream space from the reformed gas supply port of the reformed gas supply pipe is rectified by the rectifying plate to the axial center portion and the outer periphery of the catalyst layer. Since the parts flow alternately, the reformed gas can be uniformly reacted with the entire catalyst layer, and the entire catalyst layer can be used effectively.

  According to the present invention, the reformed gas can be uniformly fed into the entire catalyst layer, and the entire catalyst layer can be used effectively. In addition, a high reaction rate can be obtained by keeping the upstream side of the catalyst layer at a relatively high temperature by the heat insulating material. On the other hand, the downstream side of the catalyst layer is not provided with a heat insulating material, so that it is kept at a relatively low temperature, and the carbon monoxide concentration can be kept low by chemical equilibrium.

(First embodiment)
FIG. 1 is an overall view showing a shift reaction apparatus according to the present embodiment. 2 is a plan view showing the first rectifying plate in FIG. 1, and FIG. 3 is a plan view showing the second rectifying plate in FIG.

  As shown in FIG. 1, reference numeral “1” denotes a shift reaction apparatus that produces a hydrogen-containing gas used as a power generation fuel in a fuel cell system. This shift reaction apparatus 1 includes a cylindrical reaction vessel 2 arranged in the vertical direction, a catalyst layer 3 accommodated in the reaction vessel 2, and one end in the axial direction of the reaction vessel 2 passing through the inside of the catalyst layer 3. Two reformed gas supply pipes 4 that extend to the side and are spaced apart from each other, and a reformed gas discharge port 5 provided on the other axial end side of the reaction vessel 2.

  The reaction vessel 2 has a cylindrical body 2A, a lid 2B that closes one axial end of the cylindrical body 2A, and another lid 2C that closes the other axial end of the cylindrical body 2A. ing. Further, in the reaction vessel 2, the space between the lid 2B and the catalyst layer 3 is an upstream space S1, and the space between the lid 2C and the catalyst layer 3 is a downstream space S2. In the upstream space S <b> 1, the front end side of the reformed gas supply pipe 4 protrudes from the catalyst layer 3.

The catalyst layer 3 is formed using a catalyst made of noble metal, Cu, or the like, and reformed gas (CO ₂ , CO, CH ₄ , H ₂ ) flows through the interior of the catalyst layer 3 through the reformed gas supply pipe 4. In this case, the shift reaction represented by CO + H ₂ O → H ₂ + CO ₂ is promoted.

Air introduction valves 6 and 6, which are air introduction ports, are provided on the upstream side of the reformed gas supply pipes 4 and 4, respectively. A small amount of air introduced from the air introduction valves 6 and 6 reacts with the H ₂ contained in the reformed gas flowing in the reformed gas supply pipe 4 and reacts with the heat generated at this time. This will shorten the startup time.

  Here, as shown in FIG. 1, the first rectifying plates 10, 10,... And the second rectifying plates 11, 11,. It is buried in. The first rectifying plate 10 is formed as an annular plate using a metal material or the like, for example, and a through hole 10A through which the reformed gas flows is formed in the axial center. In addition, the first rectifying plate 10 is provided with pipe insertion holes 10B and 10B through which the reformed gas supply pipe 4 is inserted at positions opposed to each other in the radial direction across the through hole 10A. Further, the second rectifying plate 11 is formed as a circular plate using a metal material or the like, for example. The second rectifying plate 11 is provided with other pipe insertion holes 11A and 11A through which the reformed gas supply pipe 4 is inserted. Further, the reformed gas flows through the outer peripheral side of the second rectifying plate 11.

Reference numeral “7” denotes a CO selective oxidizer for oxidizing CO (carbon monoxide) contained in the reformed gas outlet 5 to CO ₂ (carbon dioxide). The quality gas discharge port 5 and the pipe 8 are connected.

In the present embodiment configured as described above, as shown in FIG. 1, the first rectifying plates 10, 10,... And the second rectifying plates 11, 11,. The reaction vessel 2 is buried alternately with respect to the axial direction. For this reason, the reformed gas introduced into the reaction vessel 2 through the reformed gas supply pipe 4 is rectified by the rectifying plates 10 and 11 with the axial center portion (in the direction of arrow A in FIG. 1) and the outer peripheral portion (in FIG. 1). 1 (in the direction of arrow B in FIG. 1) can be circulated alternately, the reformed gas can be uniformly contacted with the entire catalyst layer 3, and the entire catalyst layer 3 can be used effectively. Further, by causing the reformed gas to uniformly contact and react with the entire catalyst layer 3 by the rectifying plates 10 and 11, the radial temperature distribution in the reaction vessel 2 can be made uniform, and the reaction center of the catalyst layer 3 can be made uniform. It is possible to prevent the part temperature from becoming too high. Therefore, the shift reaction represented by CO + H ₂ O → H ₂ + CO ₂ can be efficiently performed by the catalyst layer 3, the hydrogen concentration in the reformed gas can be increased, and the carbon monoxide concentration can be reduced. .

,
Further, since an air introduction valve 6 is provided in the middle of the reformed gas supply pipe 4, the reformed gas is modified in a state where a small amount of air introduced from the air introduction valve 6 and the reformed gas are mixed. By passing the gas through the quality gas supply pipe 4, the air reacts with H ₂ , CO, and CH ₄ contained in the reformed gas, and the generated heat is transferred to the catalyst layer 3 to shorten the startup time of the catalyst layer 3. can do.

Furthermore, since the reformed gas supply pipe 4 is configured to penetrate through the inside of the catalyst layer 3, the reformed gas flowing between the reformed gas supply pipe 4 and the catalyst layer 3 is passed through the inside of the catalyst layer 3. Heat exchange can be performed. As a result, the catalyst layer 3 can be kept at a high temperature (200 ° C. to 300 ° C.).
(Second Embodiment)

Next, FIG. 4 shows a second embodiment according to the present invention. In this embodiment, the same components as those in the first embodiment are denoted by the same reference numerals. The description will be omitted.
Here, the heat insulating material 20 is formed as a covered cylindrical body, and is formed using a heat-resistant material such as rock wool, glass wool, ceramic fiber, or the like. As shown in FIG. 4, the heat insulating material 20 is located on the outer peripheral side of the reaction vessel 2 at a portion of the reaction vessel 2 positioned upstream of the reformed gas flowing inside the catalyst layer 3. It is attached so that it fits without a gap and covers from the outside.

  As a result, the upstream side of the catalyst layer 3 can be kept at a relatively high temperature (for example, about 300 ° C.), and the reaction rate can be increased. On the other hand, since the heat insulating material 20 is not provided on the downstream side of the catalyst layer 3, it is possible to keep the downstream side of the catalyst layer 3 at a relatively low temperature (for example, about 200 ° C.) and reduce the carbon monoxide concentration by chemical equilibrium. it can.

  In the first embodiment, the first rectifying plate 10 is provided with pipe insertion holes 10B and 10B through which the reformed gas supply pipe 4 is inserted at positions opposed to each other in the radial direction across the through hole 10A. In addition, it has been described that the second rectifying plate 11 is provided with pipe insertion holes 11A and 11A through which the reformed gas supply pipe 4 is inserted. However, the present invention is not limited to this. For example, as in the first modification shown in FIGS. 5 and 6, the third rectifying plate 10 ′ has a through hole 10 A ′ and pipe insertion holes 10 B ′ and 10 B ′. , And through holes 11A ′, 11A ′,... And pipe insertion holes 11B ′, 11B ′ at intervals in the circumferential direction as shown in FIG. Alternatively, the third rectifying plate 10 ′ and the fourth rectifying plate 11 ′ may be alternately embedded in the catalyst layer 3.

  In the first embodiment, the case where the first rectifying plate 10 and the second rectifying plate 11 are embedded in the catalyst layer 3 has been described as an example. However, the present invention is not limited to this, and the rectifying plate may be eliminated as in the second modification shown in FIG. Even in this case, the flow of the reformed gas flowing through the reformed gas supply pipe 4 (arrow C in FIG. 7) and the flow of the reformed gas flowing through the catalyst layer 3 (arrow D in FIG. 7) The counterflows can be opposite to each other. Therefore, for example, the catalyst layer 3 can be heated by heat radiation from the reformed gas having an appropriate temperature of about 220 ° C., and the catalyst layer 3 can be favorably started up.

1 is an overall view showing a shift reaction apparatus according to a first embodiment of the present invention. It is a top view which shows the 1st baffle plate in FIG. 1 alone. It is a top view which shows the 2nd baffle plate in FIG. It is a general view which shows the shift reaction apparatus which concerns on the 2nd Embodiment of this invention. It is a top view which shows the 3rd baffle plate by the 1st modification of this invention. It is a top view which shows the 4th baffle plate by the 1st modification of this invention. It is a general view which shows the shift reaction apparatus by the 2nd modification of this invention. It is a general view which shows the shift reaction apparatus by a prior art.

Explanation of symbols

1, 1 'shift reactor 2 reaction vessel 3 catalyst layer 4 reformed gas supply pipe 5 reformed gas discharge port 6 air introduction valve (air introduction port)
DESCRIPTION OF SYMBOLS 10 1st baffle plate 10 '3rd baffle plate 11 2nd baffle plate 11' 4th baffle plate 20 Heat insulating material S1 Upstream space S2 Downstream space

Claims (4)

A reaction vessel;
A catalyst layer filled in the reaction vessel and forming an upstream space with one side of the reaction vessel ,
The reaction vessel is arranged in the vertical direction, the upstream space is formed on one side in the vertical direction in the reaction vessel, and between the other side in the vertical direction in the reaction vessel and the catalyst layer. Provide downstream space,
Reformation that passes through the downstream space from the other side of the reaction vessel and penetrates the inside of the catalyst layer from the downstream side to the upstream side of the catalyst layer, and the leading end side supplies the reformed gas into the upstream space. A reformed gas supply pipe opening into the upstream space as a gas supply port;
A reformed gas outlet provided on the other side of the reaction vessel ,
A shift reaction apparatus, wherein a plurality of the reformed gas supply pipes are provided and the respective reformed gas supply pipes are provided apart from each other . The shift reaction apparatus according to claim 1, wherein the reformed gas supply pipe is provided with an air introduction port for mixing air with the reformed gas. Claim 1 on an outer peripheral surface of said reaction vessel is positioned upstream of the reformed gas flowing through the catalyst layer is provided insulation, on the downstream side, characterized in that not provided with the heat insulating material Or the shift reaction apparatus of Claim 2 . The reforming gas from the reforming gas supply port is reformed inside the catalyst layer so that the reforming gas is discharged from the reforming gas discharge port through the axial center and the outer periphery of the catalyst layer alternately. The shift reaction apparatus according to any one of claims 1 to 3, wherein a plurality of rectifying plates for controlling the gas flow direction are embedded.

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