JP5053029B2 - Fuel cell system - Google Patents

Description

  The present invention relates to a fuel cell system that generates power using a hydrogen rich gas obtained by reforming a raw material gas as an energy source (fuel).

  In recent years, coupled with measures to prevent global warming, the departure of energy from crude oil dependence has become an important issue on a global scale, and not only developed countries in Europe, where efforts for environmental conservation are ahead, but also the United States and Japan. Even in Asian countries, efforts to put fuel cells that use hydrogen-rich gas as an energy source into practical use have become active.

  Much research has been conducted on a method for producing a hydrogen-rich gas used as a fuel for a fuel cell. At present, the most inexpensive and highly feasible production methods are natural gas, LPG, kerosene, gasoline, methanol as raw materials. In this method, hydrogen-rich reformed gas is produced by reforming these using dimethyl ether or the like.

  However, when the above method is adopted, carbon monoxide (CO) is by-produced in the reforming step, so that a considerable amount of CO is mixed in the hydrogen-rich reformed gas. Since this CO poisons the fuel cell and lowers the power generation efficiency, several studies have been conducted on its removal method. For example, a CO removal method using a selective oxidation catalyst (selective oxidation). Catalytic methods) and CO removal methods (adsorption methods) using adsorbents are being studied.

The selective oxidation catalyst method is a technology that is being developed mainly for stationary fuel cells (including household fuel cells), and reformed gas using a catalyst by adding air or oxygen to the reformed gas. This is a technique for removing CO by selectively oxidizing and removing it as CO ₂ to prevent poisoning of the fuel cell by CO. The feature of the present technology is that it is a normal pressure process and that the apparatus can be made compact by being able to be used at a relatively high superficial velocity (SV), but has the following problems.

  That is, (1) In order to sufficiently reduce the CO concentration in the reformed gas, it is necessary to introduce excess air or oxygen. (2) Since the selective oxidation catalytic reaction is an exothermic reaction, the reaction temperature remains constant in response to changes in conditions such as changes in the inlet gas composition of the catalyst layer. It is difficult to maintain the reaction temperature, and if the reaction temperature rises too much, the catalyst will be deteriorated. (3) Furthermore, a catalyst carrying a noble metal such as platinum (Pt) is used as the catalyst. There are problems such as high.

  On the other hand, as an adsorption method, the inventors of the present application disclosed in Patent Document 1 by adsorbing and removing CO in the reformed gas using a CO adsorbent that selectively adsorbs CO, and calories are added to the CO adsorbent after CO adsorption. A method of producing hydrogen gas for fuel cells that regenerates CO adsorbent through gas was proposed.

  However, the method of removing CO by the adsorption method requires a larger amount of catalyst than the oxidation catalyst method, and it is difficult to increase the SV value of the gas to be treated. Has a problem. In particular, for a fuel cell system whose installation area is restricted, such as a household fuel cell system, downsizing of the device size is an important development issue.

In addition, in fuel cells, how to reduce the running cost and generate power is a major issue for full-scale dissemination, and further improvement in energy efficiency is required.
JP 2006-164661 A (Claims etc.)

  Accordingly, an object of the present invention is to provide a fuel cell system capable of realizing a compact CO removal device while enabling operation with higher energy efficiency than conventional ones.

  The invention described in claim 1 includes a reformed gas production apparatus having a reformer that reforms a raw material gas to obtain a hydrogen-rich reformed gas, and adsorbs and removes CO from the reformed gas to remove the CO removed gas. A fuel cell system comprising a CO removing device to be obtained and a fuel cell that generates electricity by reacting the CO removing gas supplied to the stack with an oxygen-containing gas, the CO removing device being filled with a CO adsorbent It consists of at least three CO adsorption towers, and while performing the CO adsorption removal operation in any one tower, the stack off gas of the fuel cell is circulated as a regeneration gas in at least one other tower, thereby The heating / regeneration operation is performed, and the regeneration offgas from at least one other tower is used as the fuel for the reformer. On the other hand, the raw material gas is circulated as a cooling gas in the remaining tower, and the heating is performed. It performs cooling operation CO adsorbent heated to a high temperature during the regenerating operation, a fuel cell system characterized by being configured to use the cooling off from the rest of the column as the raw material gas in the reformer.

  The invention described in claim 2 is configured such that a part of the raw material gas to be circulated to the remaining tower is used in addition to the stack-off gas of the fuel cell as the regeneration gas to be circulated to the at least one other tower. The fuel cell system according to claim 1.

  The invention according to claim 3 is configured such that a part of the regeneration off-gas from the at least one other tower is heated in a heat exchanger and circulated and used as a regeneration gas for the at least one other tower. The fuel cell system according to claim 1 or 2.

  A fourth aspect of the present invention is the fuel cell system according to the first or second aspect, wherein the heating / regeneration operation is performed under reduced pressure.

  According to a fifth aspect of the present invention, there is provided a reformed gas production apparatus having a reformer for reforming a raw material gas to obtain a hydrogen-rich reformed gas, and removing CO from the reformed gas by adsorbing and removing CO. A fuel cell system comprising a CO removing device to be obtained and a fuel cell that generates electricity by reacting the CO removing gas supplied to the stack with an oxygen-containing gas, the CO removing device being filled with a CO adsorbent It consists of at least three CO adsorption towers, and while performing the CO adsorption removal operation in any one tower, the stack off gas of the fuel cell is circulated as a regeneration gas in at least one other tower, thereby While performing the heating / regeneration operation and using the regenerated off-gas from at least one other tower as fuel for the reformer, the CO removal gas is circulated as a cooling gas to the remaining tower, After the cooling operation of CO adsorbent heated to a high temperature during the serial heating and regeneration, a fuel cell system characterized by being configured to supply to the stack of the fuel cell.

  The invention described in claim 6 is a reformed gas production apparatus having a reformer that reforms a raw material gas to obtain a hydrogen-rich reformed gas, and adsorbs and removes CO from the reformed gas, A fuel cell system comprising a CO removal device to be obtained and a fuel cell that generates electricity by reacting the CO removal gas supplied to the stack with an oxygen-containing gas, the CO removal device being filled with a CO adsorbent It comprises at least three CO adsorption towers, and while performing the CO adsorption removal operation in any one tower, the fuel cell stack-off gas is circulated as a cooling gas in another tower, A cooling operation of the CO adsorbent that has become hot during regeneration is performed, and the cooling off-gas from at least one other tower is circulated as a regeneration gas to the remaining tower to perform heating and regeneration operations of the CO adsorbent. It is a fuel cell system characterized by being configured so as to use the play off-gas from the rest of the tower as a fuel for the reformer.

  The invention according to claim 7 is the heating apparatus according to any one of claims 1 to 6, wherein the adsorption tower is externally heated by using the amount of heat of the burner off gas from the reformer during the heating / regeneration operation of the CO adsorbent. 2. A fuel cell system according to item 1.

  The invention according to claim 8 is the fuel cell system according to claim 7, wherein a heating medium for externally heating the adsorption tower is steam or warm water.

  The invention according to claim 9 is directed to the adsorption tower that performs the CO adsorption removal operation after the reformed gas is used for external heating of the adsorption tower that performs the heating / regeneration operation of the CO adsorbent. It is a fuel cell system of any one of Claims 1-6 to distribute | circulate.

The invention according to claim 10 is the fuel cell system according to any one of claims 1 to 9, wherein the reformed gas manufacturing apparatus is any one of the following (a) to (e). is there.
(A) A steam reformer that reforms the source gas with steam to obtain a hydrogen-rich reformed gas (b) A steam reformer that reforms the source gas with steam to obtain a hydrogen-containing gas, and the hydrogen-containing reformer (C) Partial oxidation reformer which obtains hydrogen-rich reformed gas by reforming raw material gas by partial oxidation (d) Partial oxidation / steam reformer that reforms source gas by partial oxidation and simultaneously reforms with steam to obtain hydrogen-rich reformed gas (e) Steam that reforms source gas with steam to obtain hydrogen-containing gas An apparatus composed of a combination of a reformer and a rough separation membrane such as a ceramic filter for obtaining a hydrogen-rich reformed gas by circulating the hydrogen-containing gas to increase the hydrogen concentration

  The invention according to claim 11 is characterized in that the CO adsorbent is applied to one or more kinds of carriers selected from the group consisting of silica, alumina, activated carbon, graphite and polystyrene-based resin, with copper (I) halide and / or halogen. The fuel cell system according to any one of claims 1 to 10, which is a material supporting copper (II) chloride or a reduction treatment of the material.

  According to the present invention, the CO removal device is composed of three or more CO adsorption towers packed with a CO adsorbent, and the CO adsorption removal operation is performed in one of the towers while the fuel cell is removed in another tower. By using the stack off gas, reforming source gas, etc., the CO adsorbent heating / regeneration operation and the cooling operation after regeneration are performed in parallel to effectively utilize the sensible heat of the stack off gas of the fuel cell. While enabling high energy efficiency operation, the time required for CO adsorbent heating / regeneration operation and cooling operation can be shortened, and the SV value of the circulating gas can be set large. As a result that the amount can be significantly reduced as compared with the conventional case, the CO removal device can be made compact.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the flowcharts of FIGS.

Embodiment 1
An example of an embodiment of a fuel cell system according to the present invention is shown in the flowchart of FIG. In the figure, reference numeral 1 is a reformer 1 for reforming a reforming raw material gas to obtain a hydrogen-rich reformed gas, and reference numeral 2 is a CO adsorption for removing CO from the reformed gas to obtain a CO removal gas. A CO removing device 2 filled with an agent, and a reference numeral 3 denote a fuel cell 4 that generates electric power using the CO removing gas as an energy source (fuel). Hereinafter, it demonstrates in detail for every apparatus.

(Reformer)
The reformer 1 according to the present invention may be configured by combining, for example, a steam reformer 1a and a transformer 1b that are normally used. After reforming the raw material gas containing hydrocarbons such as natural gas such as city gas with steam in the reformer 1a to make the gas mainly composed of H ₂ and CO, this gas is transformed in the transformer 1b. Further, water vapor is added to the modified gas to produce a reformed gas B containing H ₂ as a main component (hydrogen-rich). In the reformed gas B, about 0.5% CO remains in addition to H ₂ and a small amount of CO ₂ , CH ₄ , H ₂ O, and the like. In addition, since the adsorption reaction is promoted at a lower temperature in the CO removal apparatus 2 in the subsequent process, a heat exchanger (the heat exchanger for cooling the high-temperature reformed gas B between the reformer 1 and the CO removal apparatus 2). It is desirable to provide a device (not shown).

(CO removal device)
As the CO removal apparatus 2 of the present invention, for example, as shown in FIG. 1, a configuration comprising three CO adsorption towers (2a, 2b, 2c) filled with a CO adsorbent may be employed. Hereinafter, the operation in each tower will be described in order.

    [CO adsorption removal operation]: The reformed gas B is allowed to pass through any one column (2a in this example), and CO in the reformed gas B is selectively adsorbed and removed to obtain a CO removed gas C. As the CO adsorbent, copper (I) halide and / or copper (II) halide was supported on one or more carriers selected from the group consisting of silica, alumina, activated carbon, graphite and polystyrene resin. A material or a material obtained by subjecting this material to reduction treatment is preferably used. Among them, a material in which copper (I) chloride is supported on an alumina support is highly recommended for CO. Such a CO adsorbent carrying copper halide has a CO adsorption capacity several to several tens of times that of conventional adsorbents such as zeolite molecular sieves, carbon molecular sieves, activated carbon, or activated alumina. The adsorption tower can be greatly reduced in size.

    [Heating / regeneration operation]: For another CO adsorption tower (2b in this example) used for the CO adsorption removal operation, the CO adsorption capacity exceeded the CO adsorption capacity in order to maintain the adsorption performance of the CO adsorbent. Before the CO leaks from the outlet side of the tower 2b, it is necessary to regenerate the CO adsorbent. The regeneration of the CO adsorbent is performed while circulating a gas substantially free of CO in order to desorb and wash the CO adsorbed at the adsorption site. Further, since the CO desorption reaction is promoted as the temperature increases, it is desirable that the CO adsorbent be regenerated (washed) in a state heated to 40 to 150 ° C. In order to satisfy such conditions, all or part of the stack-off gas D of the fuel cell 3 may be used as a gas that does not substantially contain CO used as the regeneration gas. Since the stack-off gas D of the fuel cell 3 has a high temperature at the time of stack operation of the fuel cell of about 80 ° C., the CO adsorbent regeneration efficiency can be improved by using the heat quantity of the gas D. Further, the stack off gas D is used after, for example, heat exchange with the combustion off gas of the reformer 1a heating burner in the heat exchanger 4 to increase the stack off gas temperature to 100 to 200 ° C. The CO adsorbent can be regenerated efficiently and in a short period of time compared to the case of regenerating by heating with a heater or the like from the outside. Then, the regeneration offgas E from the tower 2b is used as fuel for heating the reformer 1a. Since the regenerated off-gas E contains unreacted (unburned) hydrogen discharged from the fuel cell 3 stack and CO desorbed from the CO adsorbent, the combustion heat of these gas components is reduced. It can be recovered and used effectively, and the amount of heating fuel supplied from the outside to the reformer 1a can be reduced. In order to further reduce the time required for regeneration of the CO adsorbent by increasing the SV value of the regeneration gas during the heating / regeneration operation and to adjust the combustion calorie of the regeneration offgas E, the cooling gas is used during the cooling operation described later. A part A1 of the raw material gas A supplied to the CO adsorption tower 2c may be added to the stack off gas D. In this case, since part A1 of the raw material gas A is added to the stack-off gas D at room temperature, when using the heat exchanger 4, it is added upstream of the heat exchanger 4 and heated by the heat exchanger 4 before the CO adsorption tower. It is good to introduce into 2b.

  [Cooling operation]: Further, for the remaining CO adsorption tower (2c in this example) after the heating / regeneration operation, in order to prepare for the next CO adsorption removal operation, for example, the raw material gas A at normal temperature is circulated and heated. -Cool the CO adsorbent that has become hot during the regeneration operation. As the source gas A, in addition to the city gas described above, a gaseous source mainly composed of hydrocarbon components such as natural gas, propane gas, and COG can be used. Also in this case, the CO adsorbent can be cooled more efficiently and in a shorter time than when the CO adsorbent is cooled from the outside of the CO adsorption tower 2c using cooling water or the like. The cooling off gas F from the tower 2c is used as a raw material gas for the reformer 1a. As a result, the sensible heat of the CO adsorbent that has become high during the heating / regeneration operation can be recovered and effectively used, and the consumption of the heating fuel supplied from the outside to the reformer 1a can be further reduced.

(Fuel cell)
Since each CO adsorption tower is operated by cyclically switching the above CO adsorption removal operation, heating / regeneration operation, and cooling operation, any one of the CO adsorption towers can always be in the state of the CO adsorption removal operation. The CO-removing gas C rich in hydrogen can be continuously supplied from the CO removing device 1 to the stack of the fuel cells 3. Then, in the stack of the fuel cell 3, the hydrogen-rich CO removal gas C is reacted with an oxygen-containing gas such as air or oxygen introduced separately to generate power. Thereby, it is possible to continuously generate power stably for a long time while preventing poisoning of the fuel cell by CO.

  As described above, since the CO adsorbent removal operation is performed in one of the towers, and the CO adsorbent heating / regeneration operation and the cooling operation are performed in parallel in the other towers, The time required for cooling can be greatly shortened, the SV value of the circulating gas can be set large, and the amount of CO adsorbent required for the CO removal device 1 as a whole can be greatly reduced compared to the conventional case. Compact size can be realized.

  Hereinafter, although another embodiment will be described, description of parts common to the first embodiment will be omitted, and only different parts will be described in detail.

[Embodiment 2]
In the first embodiment, an example in which a part A1 of the source gas A is added to the stack-off gas D in order to increase the SV value of the regeneration gas has been shown, but instead of adding a part A1 of the source gas A, As shown in FIG. 2, a part E1 of the regeneration offgas E from the CO adsorption tower 2b may be circulated to the stack offgas D line, and the temperature may be raised in the heat exchanger 4 for use. In the first embodiment, the addition of a part A1 of the raw material gas A to the stack off gas D also serves to adjust the combustion calorie of the regenerated off gas E used as a heating fuel for the reformer 1a. However, for this purpose, in this embodiment, as shown in the figure, for example, a part A1 of the source gas A may be added downstream from the circulation line.

[Embodiment 3]
As shown in FIG. 3, in Embodiment 1 (FIG. 1), a throttle valve 5 is installed upstream of the CO adsorption tower 2b engaged in the heating / regeneration operation, and a vacuum pump 5 is installed on the downstream side. You may comprise so that the stack off gas D may be distribute | circulated to the tower 2b, decompressing with the throttle valve 5, reducing the inside of the CO adsorption tower 2b with the pump 6. FIG. By flowing a high-temperature regeneration gas under reduced pressure, the desorption of CO from the CO adsorbent is further promoted, and more efficient regeneration of the CO adsorbent becomes possible.

[Embodiment 4]
In the first to third embodiments, the example in which the raw material gas A is used as the cooling gas for the cooling operation of the CO adsorbent is shown. However, as shown in FIG. 4, the CO removal gas C after the CO adsorption removal is cooled. It may be used as a working gas. The CO removal gas C (that is, the reformed gas B from which CO has been removed) has a flow rate about five times that of the raw material gas A when the city gas mainly containing CH ₄ is used as the raw material gas A. Therefore, the SV value of the cooling gas can be increased as compared with the first to third embodiments, and the cooling efficiency of the CO adsorbent can be further increased.

[Embodiment 5]
In the first to fourth embodiments, the example in which the raw material gas A is used as the cooling gas used for the cooling operation of the CO adsorbent has been shown, but the stack off gas D of the fuel cell 3 can also be used as shown in FIG. It is. Since the stack off gas D has about three times as much gas as the source gas A, the CO adsorbent can be cooled more efficiently, and the CO adsorbent is not completely regenerated during the heating / regeneration operation. In both cases, the CO adsorbent can be completely regenerated by circulating a large amount of the stack off gas D during the cooling operation. Since the stack off gas D has a temperature of about 50 to 80 ° C. at the stack outlet of the fuel cell 3, when used for the cooling operation of the CO adsorbent, the heat exchanger 4 ′ or the like is used to reach the room temperature. It is desirable to use after lowering the temperature. The stack off gas D (cooling off gas F) after being used for the cooling operation is heated using, for example, the heat exchanger 4, and then introduced into the adsorption tower 2b where the heating / regeneration operation is performed, thereby serving as a regeneration gas. Can be used. Further, the stack off gas D (regeneration off gas E) after being used as the regeneration gas can be used as a heating fuel for the reformer 1a.

[Embodiment 6]
In the first to fifth embodiments, the CO adsorbent is heated and regenerated by circulating a high-temperature gas such as the stack-off gas D through the other CO adsorption tower 2b and heating the CO adsorbent using the sensible heat. Although the example of performing the regeneration is shown, the adsorption tower 2b may be heated from the outside (hereinafter referred to as “external heating”) at the same time as circulating the high-temperature gas. Thereby, the temperature of the CO adsorbent can be raised to the regeneration temperature more rapidly, so that the CO adsorbent can be regenerated more efficiently. As the amount of heat at the time of external heating, for example, as illustrated in FIGS. 6 and 7, the amount of heat of the off-gas (hereinafter referred to as “burner off-gas”) G of the heating burner 7 of the reformer 1a can be effectively used. .

  FIG. 6 shows the production of water vapor (steam) H using the amount of heat of the burner off gas G from the reformer 1a, and this water vapor H is introduced into the jacket 8 of the CO adsorption tower 2b equipped with the jacket 8 as a heating medium. In addition, an example in which the CO adsorption tower 2b is externally heated is shown. By using the water vapor H as a heating medium, it is possible to use the latent heat of condensation from water vapor to water as compared with the case where a high-temperature gas is used as the heating medium, so that it is possible to heat the CO adsorbent with a significantly smaller amount of gas. And heating efficiency can be increased. As shown in the figure, the condensed water J discharged from the CO adsorption tower 2b can be effectively used as a raw material for reforming steam in the reformer 1a.

  FIG. 7 shows the production of hot water K of, for example, about 70 to 95 ° C. using the calorie of the burner off gas G from the reformer 1a, and the CO adsorption tower 2b equipped with the jacket 8 using this hot water K as a heating medium. Is an example in which the CO adsorption tower 2b is externally heated. By using the hot water K as the heating medium, the amount of heat of the heating medium per unit volume flow rate can be increased compared with the case where a high-temperature gas is used as the heating medium. Thus, it is possible to increase the heating efficiency. The hot water L discharged from the CO adsorption tower 2b can be reused, for example, as hot water stored in a water heater (not shown) and used at home. Of course, a part of the hot water L can be used as a raw material for steam for reforming in the reformer 1a.

  Further, when the CO adsorption towers 2a to 2c provided with the jacket 8 as described above are used, the cooling water and the hot water are circulated to the jacket 8 during the cooling operation and the adsorption operation, while the cooling water is circulated. It is possible to cool the adsorbent and adsorb the CO gas. Thereby, at the time of cooling operation, compared with the case where it cools only with cooling gas, more efficient cooling is attained. In addition, during the adsorption operation, the temperature increase of the CO adsorbent due to the heat generated by the CO adsorption reaction can be surely prevented, so that the CO adsorption reaction can be further promoted.

[Embodiment 7]
In the sixth embodiment, steam or high-temperature hot water is used as the heat medium for external heating of the CO adsorption tower 2b performing the heating / regeneration operation. However, as shown in FIG. Can be used as a heat medium for external heating of the CO adsorption tower 2b that is performing the heating / regeneration operation before being introduced into the CO adsorption tower 2a that is performing the CO adsorption removal operation. As described above, the high-temperature reformed gas B itself is cooled and cooled down by using it as a heat medium for external heating, and this low-temperature reformed gas B ′ is subjected to CO adsorption removal operation. Therefore, the CO adsorption removal operation is further promoted.

(Modification)
In order to reduce the size of the CO adsorbing apparatus using the CO adsorbent, it is effective to set the time for each operation of CO adsorption removal, heating / regeneration, and cooling as short as possible to shorten the cycle time. Of these three operations, the heating / regeneration operation and the cooling operation take time to increase the temperature and cooling of the CO adsorbent, and are therefore rate limiting when attempting to shorten the cycle time. The heating / regeneration operation can be shortened by setting the regeneration gas to a high temperature, but the cooling operation is the most time-consuming operation. In the first to seventh embodiments, the CO removing device 1 is configured by three CO adsorption towers, and each of the CO adsorption removal, heating / regeneration, and cooling operations is performed in each one tower. In order to further shorten the cycle time, it is possible to change the number of towers to be configured by four or more CO adsorption towers and perform the above operations. For example, in the case of four towers, as in the first to seventh embodiments, the CO adsorption removal operation is performed in one tower and the heating / regeneration operation is performed in another tower, but the cooling operation is performed in the remaining two towers. You can do it. For example, in the case of five towers, the CO adsorption removal operation is performed in one tower as in Examples 1 to 7, but the heating / regeneration operation is performed in another two towers, and the cooling operation is performed in the remaining two towers. You just have to do it. When heating / regeneration operation (or cooling operation) is performed in two or more towers, for example, regeneration gas (or cooling gas) may be circulated in parallel to each of these towers, or these towers are connected in series. Then, the regeneration gas (or cooling gas) may be circulated in one pass.

In the first to seventh embodiments (FIGS. 1 to 8), a dehumidifier that removes H ₂ O in the reformed gas B may be provided between the reformer 1 and the CO remover 2. As the dehumidifier, an apparatus that cools the reformed gas B and removes it as drain water or an adsorption dehumidifier can be used. When using an adsorption-type dehumidifier, an alumina-based or silica-based adsorbent can be used as the adsorbent, and these can be used in combination. Thereby, the hydrogen concentration of the CO removal gas C introduced into the stack of the fuel cell 3 is increased, and the power generation efficiency is further improved.

  In the first to seventh embodiments, a combination of the reformer 1a and the transformer 1b is illustrated as the reformer 1. However, a crude separation membrane such as a ceramic filter may be used instead of the transformer 1b. That is, in the above embodiment, the reformer is exemplified by a device configuration in which the raw material gas is reformed after being reformed with steam to obtain a hydrogen-rich reformed gas. An apparatus configuration in which a hydrogen-rich reformed gas is obtained by increasing the hydrogen concentration by circulating the membrane can be naturally applied.

Furthermore, depending on the CO adsorption performance of the CO adsorbent, a process using only the reformer 1a without the transformer 1b may be established. That is, as a reformer, an apparatus configuration composed only of a steam reformer that can obtain a reformed gas only by reforming with steam is also applicable. When the transformer 1b is omitted, the amount of H ₂ produced in the reformed gas B is reduced, but the amount of CO ₂ produced is also reduced, so that the hydrogen purity of the reformed gas (CO removed gas) C after CO removal increases. The efficiency of the fuel cell 3 is improved. Moreover, there is also an advantage that the equipment cost is reduced by omitting the transformer 1b using the noble metal catalyst. Furthermore, instead of steam reforming, partial oxidation is used to obtain a reformed gas, or a device configuration consisting of only a partial oxidation reformer, or reforming by partial oxidation and reforming by steam at the same time An apparatus configuration consisting only of a partial oxidation / steam reformer that is adapted to obtain gas can also be applied.

In order to confirm the effect of the present invention, a test for simulating the operation of the CO removal apparatus having the configuration of the first embodiment was performed using a CO removal apparatus including three CO adsorption towers. Table 1 shows the test conditions. As the CO adsorbent packed in the CO adsorption tower, copper (I) chloride-supported alumina was used. In the heating / regeneration operation and the cooling operation, a high-temperature regeneration gas and a low-temperature (room temperature) cooling gas were used, respectively, and external heating by a heater and external cooling by water cooling were used in combination.

  FIG. 9 shows the change over time in the CO concentration in the simulated reformed gas (CO removal gas) after CO removal. The CO concentration in the hydrogen-rich gas supplied to the stationary fuel cell needs to be 10 ppm or less. As is clear from the figure, by adopting the configuration of the CO adsorbing device according to the present invention, the CO concentration is very low, 1 ppm or less. It was confirmed that fuel could be supplied to the fuel cell stack with a low CO concentration.

  In addition, as a comparative example, a CO removal apparatus composed of two CO adsorption towers is used, and CO adsorption removal operation is performed in one tower, heating / regeneration operation and cooling operation are performed in parallel in the other tower, and these operations are performed simultaneously. A test of driving by switching to a click was conducted. The test conditions are the same for the heating / regeneration operation and cooling operation as in the above example (Table 1), and for the CO adsorption removal operation, the adsorption temperature and the simulated reformed gas composition are the same as in the above example (Table 1). However, the cycle time of the CO adsorption removal operation is set to 20 minutes, which is the total cycle time of the heating / regeneration operation and the cooling operation, and the GHSV at the time of the CO adsorption removal operation has a CO concentration in the CO removal gas of the above example. It set so that it might become the same 1 ppm or less.

Table 2 shows a comparison of GHSV and required amount of CO adsorbent during the CO adsorption removal operation in each of the above Examples and Comparative Examples. As is clear from the table, in the example, as compared with the comparative example, it was confirmed that the required CO adsorbent amount can be reduced by 37% as a result of significantly increasing the GHSV during the CO adsorption removal operation.

1 is a flowchart showing a configuration of a fuel cell system according to Embodiment 1. FIG. FIG. 5 is a flowchart showing a configuration of a fuel cell system according to Embodiment 2. It is a flowchart which shows the structure of the fuel cell system which concerns on Embodiment 3. FIG. 6 is a flowchart showing a configuration of a fuel cell system according to Embodiment 4. FIG. 9 is a flowchart showing a configuration of a fuel cell system according to Embodiment 5. FIG. 10 is a flowchart showing a configuration of a fuel cell system according to Embodiment 6. FIG. 10 is a flowchart showing another configuration of the fuel cell system according to Embodiment 6. It is a flowchart which shows the structure of the fuel cell system which concerns on Embodiment 7. It is a graph which shows a time-dependent change of CO density | concentration in the reformed gas after CO adsorption removal in an Example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Reformer 1a ... Reformer 1b ... Transformer 2 ... CO removal apparatus 2a, 2b, 2c ... CO adsorption tower 3 ... Fuel cell 4, 4 '... Heat exchanger 5 ... Throttle valve 6 ... Vacuum pump 7 ... Burner 8 for heating ... Jacket A ... Raw material gas B ... Reformed gas B '... Low temperature reformed gas C ... CO removal gas D ... Stack off gas E ... Regeneration off gas F ... Cooling off gas G ... Burner off gas H ... Steam J ... Condensation Water K, L ... warm water

Claims (11)

A reformed gas production apparatus having a reformer that reforms a raw material gas to obtain a hydrogen-rich reformed gas, a CO removal apparatus that absorbs and removes CO from the reformed gas to obtain a CO removed gas, and supplies the stack A fuel cell system comprising: a fuel cell that generates electricity by reacting the CO-removed gas with an oxygen-containing gas,
The CO removal device comprises at least three CO adsorption towers filled with a CO adsorbent;
While performing the CO adsorption removal operation in any one tower,
In another at least one tower, the stack off gas of the fuel cell is circulated as a regeneration gas to perform heating / regeneration operation of the CO adsorbent, and the regeneration off gas from the at least one other tower is used as a fuel for the reformer. I use it as
The raw material gas is circulated as a cooling gas in the remaining tower, the CO adsorbent that has become hot during the heating / regeneration operation is cooled, and the cooling off-gas from the remaining tower is used for the reformer. A fuel cell system configured to be used as a source gas.   2. The fuel cell system according to claim 1, wherein a part of the raw material gas to be circulated to the remaining tower is used in addition to the stack off gas of the fuel cell as the regeneration gas to be circulated to the at least one other tower. .   3. The configuration according to claim 1, wherein a part of the regeneration off-gas from the at least one other tower is heated in a heat exchanger and circulated as a regeneration gas for the at least one other tower. Fuel cell system.   The fuel cell system according to claim 1 or 2, wherein the heating / regeneration operation is performed under reduced pressure. A reformed gas production apparatus having a reformer that reforms a raw material gas to obtain a hydrogen-rich reformed gas, a CO removal apparatus that absorbs and removes CO from the reformed gas to obtain a CO removed gas, and supplies the stack A fuel cell system comprising a fuel cell that generates electric power by reacting the CO-removed gas with an oxygen-containing gas,
The CO removal device comprises at least three CO adsorption towers filled with a CO adsorbent;
While performing the CO adsorption removal operation in any one tower,
In another at least one tower, the stack off gas of the fuel cell is circulated as a regeneration gas to perform heating / regeneration operation of the CO adsorbent, and the regeneration off gas from the at least one other tower is used as a fuel for the reformer. I use it as
The CO removal gas is circulated as a cooling gas in the remaining towers, and after cooling operation of the CO adsorbent that has become hot during the heating / regeneration, it is supplied to the fuel cell stack. A fuel cell system. A reformed gas production apparatus having a reformer that reforms a raw material gas to obtain a hydrogen-rich reformed gas, a CO removal apparatus that absorbs and removes CO from the reformed gas to obtain a CO removed gas, and supplies the stack A fuel cell system comprising: a fuel cell that generates electricity by reacting the CO-removed gas with an oxygen-containing gas,
The CO removal device comprises at least three CO adsorption towers filled with a CO adsorbent;
While performing the CO adsorption removal operation in any one tower,
In another at least one tower, the stack off gas of the fuel cell is circulated as a cooling gas, and the CO adsorbent that has become hot during heating and regeneration described below is cooled,
After heating the cooling off-gas from at least one other tower, it is circulated as a regeneration gas to the remaining tower to perform heating / regeneration operation of the CO adsorbent, and the regeneration off-gas from the remaining tower is changed to the modified tower. A fuel cell system configured to be used as a fuel for a mass device.   The fuel cell system according to any one of claims 1 to 6, wherein the adsorption tower is externally heated by using the amount of heat of the burner off gas from the reformer during the heating / regeneration operation of the CO adsorbent.   The fuel cell system according to claim 7, wherein a heating medium for externally heating the adsorption tower is steam or warm water.   7. The reformed gas is used for external heating of an adsorption tower performing heating / regeneration operation of the CO adsorbent, and then circulated through the adsorption tower performing CO adsorption removal operation. The fuel cell system according to claim 1. The fuel cell system according to any one of claims 1 to 9, wherein the reformed gas production apparatus is any one of the following apparatuses (a) to (e).
(A) An apparatus consisting only of a steam reformer that reforms a source gas with steam to obtain a hydrogen-rich reformed gas (b) A steam reformer that reforms a source gas with steam to obtain a hydrogen-containing gas (C) Partial oxidation reforming to obtain hydrogen-rich reformed gas by reforming the raw material gas by partial oxidation (D) An apparatus consisting only of a partial oxidation / steam reformer that reforms a raw material gas by partial oxidation and simultaneously reforms it with steam to obtain a hydrogen-rich reformed gas (e) A combination of a steam reformer that obtains a hydrogen-containing gas by reforming with steam and a crude separation membrane such as a ceramic filter that obtains a hydrogen-rich reformed gas by circulating the hydrogen-containing gas to increase the hydrogen concentration apparatus   The CO adsorbent has copper (I) halide and / or copper (II) halide supported on one or more carriers selected from the group consisting of silica, alumina, activated carbon, graphite and polystyrene resin. The fuel cell system according to any one of claims 1 to 10, which is a material or a material obtained by reducing the material.

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