JP2008269807A - Fuel cell power generation system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel cell power generation system simplifying constitution of a water treatment system incorporated in the system, lengthening the life of ion exchange resin by decreasing its load, preventing flow out of a sulfur compound to a reformed water by suppressing oxidation decomposition of the ion exchange resin to keep the performance of a reforming catalyst, and enhancing economy and reliability. <P>SOLUTION: A heat exchanger 22 is installed on the downstream side of a condensed water tank 14, and an ion exchange resin tower 24 is arranged on the downstream side of the heat exchanger 22. Condensed water 18c from the condensed water tank 14 is passed through the ion exchange resin tower 24 and joined with water 18d from a cooling water tank 30, and joined water 18e is supplied to a fuel cell unit 5 as cell cooling water 18. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a fuel cell power generation system that improves the performance of a water treatment system in order to treat battery cooling water and the like.

  The fuel cell power generation system is a system that takes out electricity directly by electrochemically reacting hydrogen as a fuel and oxygen as an oxidant. This system can take out electrical energy with high efficiency, and has excellent environmental properties such as low noise and no harmful exhaust gas.

  Therefore, high demand is expected in recent years when environmental problems are taken up on a global scale. Among them, a polymer electrolyte fuel cell (PEFC) in which a solid polymer electrolyte membrane is incorporated in an electrolyte is suitable for miniaturization, and is becoming popular for small-scale business use and home use. For this reason, efforts are being made every day to further reduce costs as well as to improve power generation efficiency and quality as needs grow.

  Relatively small fuel cell power generation systems for small businesses and homes are expected to be used as so-called cogeneration systems, and are combined with heat and power to supply the generated heat and waste heat associated with power generation. Yes. As the fuel supply base for the system, currently available hydrocarbon-based raw fuels such as city gas, LP gas and kerosene are mainly used, and the raw fuel is reformed with steam. Technological development is proceeding with a focus on fuel cell power generation systems that generate electricity using hydrogen.

  By the way, the fuel cell main body generates heat due to a chemical reaction, and therefore, it is necessary to flow battery cooling water for maintaining the fuel cell main body at a predetermined operating temperature. Further, water for steam reforming of hydrocarbon fuel is indispensable for a fuel reforming system for steam reforming hydrocarbon-based raw fuel, and it is necessary to stably supply this reformed water.

  Furthermore, in the fuel cell power generation system, which is a cogeneration system, high-temperature exhaust gas is collected and cooled to acquire thermal energy, so that condensed water is generated as the exhaust gas is cooled. From the viewpoint of improving the system efficiency, it is needless to say that this condensed water is preferably used effectively as makeup water.

  That is, the fuel cell power generation system incorporates a water treatment system for treating three types of water such as battery cooling water, reforming water, and condensed water. These water treatment systems play a role of improving system efficiency by reducing or eliminating makeup water from outside the system system, and are important components that influence the performance as a cogeneration system.

  Here, a conventional example of a fuel cell power generation system including a water treatment system will be specifically described with reference to FIG. As shown in FIG. 2, the fuel cell package 1 includes a fuel reforming system 2 having a reformer burner 12, a fuel cell body 5 having an anode 5a and a cathode 5b, a decarboxylation tower 19, a heat exchanger 16, and a condensation. A composite heat exchanger 13 incorporating a water tank 14 is installed.

  Hereinafter, each component will be described along the flow of various gases and water flowing in the fuel cell package 1. First, raw fuel F, which is a hydrocarbon-based fuel, is supplied to the fuel cell package 1 from a storage facility such as a pipeline or a gas cylinder. The raw fuel F supplied to the fuel cell package 1 is sent to the fuel reforming system 2. The fuel reforming system 2 includes a desulfurizer that desulfurizes the raw fuel F, a steam reformer, a CO converter, and a CO selective oxidizer.

In the fuel reforming system 2, the raw fuel F is desulfurized in a desulfurizer, and then mixed with the vaporized reformed water 3, steam reforming reaction in a steam reformer, carbon monoxide in a CO converter ( The hydrogen-rich reformation containing methane, CO, carbon dioxide (CO ₂ ), etc., in which the CO concentration is reduced below the limit value in the fuel cell body 5 through the CO) shift reaction and the CO selective oxidation reaction in the CO selective oxidizer, etc. A quality gas 4 is produced.

  The reformed gas 4 generated in the fuel reforming system 2 is introduced into the anode 5 a of the fuel cell main body 5. Oxygen in the atmosphere is supplied to the cathode 5 b of the fuel cell body 5 through the air filter 38 by the air blower 6. In the fuel cell main body 5, hydrogen in the anode 5 a and oxygen in the cathode 5 b are reacted and consumed, and power generation is performed. The fuel cell main body 5 is circulated with battery cooling water 18 for maintaining the fuel cell main body 5 at an optimum operating temperature.

  In the fuel cell body 5, after the reaction between hydrogen and oxygen, the anode exhaust gas 7 is discharged from the anode 5a, and the cathode exhaust gas 17 is discharged from the cathode 5b. Among these, the anode exhaust gas 7 is sent to the heat exchanger 8. Waste heat recovery circulating water 10 is introduced into the heat exchanger 8 from a hot water tank 9 installed outside the fuel cell package 1, and the anode exhaust gas 7 is cooled by heat exchange with the exhaust heat recovery circulating water 10, so that the anode Exhaust gas condensed water 11 is generated. The anode exhaust gas condensed water 11 is sent to the condensed water tank 14 of the composite heat exchanger 13.

  The anode exhaust gas 7 from which the anode exhaust gas condensed water 11 has been removed by cooling in the heat exchanger 8 is introduced into the fuel inlet of the reformer burner 12 of the fuel reforming system 2. It is burned with supplied air (not shown) and used as a heat source for the steam reforming reaction in the steam reformer. At this time, since the combustion exhaust gas 15 is generated in the reformer burner 12, the combustion exhaust gas 15 is sent to the composite heat exchanger 13.

  On the other hand, the cathode exhaust gas 17 discharged from the cathode 5b of the fuel cell main body 5 consumes oxygen with power generation, and the oxygen concentration is reduced from the atmosphere. The cathode exhaust gas 17 having such a low oxygen concentration is led to a decarbonation tower 19 in the composite heat exchanger 13. Further, the battery outlet water of the battery cooling water 18 is introduced into the decarbonation tower 19 together with the cathode exhaust gas 17, and the carbon dioxide gas present in the battery cooling water 18 is removed and reduced by gas-liquid contact with the cathode exhaust gas 17. Is done. The battery cooling water 18 with reduced carbon dioxide gas is sent to the condensed water tank 14 of the composite heat exchanger 13.

  The combustion exhaust gas 15 from the reformer burner 12 and the cathode exhaust gas 17 that has passed through the decarbonation tower 19 are sent to the composite heat exchanger 13, and the heat exchanger 16 (exhaust heat from the hot water storage tank 9) inside the composite heat exchanger 13. The recovered circulating water 10 is cooled via a heat exchanger 8), and combustion exhaust gas condensed water 39 and cathode exhaust gas condensed water 40 are generated. Condensed water 39 and 40 from the exhaust gases 15 and 17 accumulate in the condensed water tank 14 together with the anode exhaust gas condensed water 11 and the battery cooling water 18 described above. The exhaust gases 15 and 17 after the condensed water 39 and 40 are removed are discharged from the composite heat exchanger 13 to the atmosphere.

  When the condensed water 11, 39, 40 and the battery cooling water 18 collected in the condensed water tank 14 leave the condensed water tank 14 by the battery cooling water pump 21, they are divided into the water systems 18a, 18b. A heat exchanger 22 for lowering the temperature of the outlet of the fuel cell main body 5 is installed in one of the divided water systems 18a, and downstream of the water system 18a, in order to remove cations and anions in the water after cooling. An ion exchange resin tower 24 filled with the ion exchange resin 23 is provided.

  Note that the battery cooling water flowing through the water system 18a is sent from above to the ion exchange resin tower 24, and is piped so as to pass through the ion exchange resin tower 24 by a downward flow. When the water system 18 a exits the ion exchange resin tower 24, it merges with the water system 18 b again, and then is supplied again to the fuel cell body 5 as the battery cooling water 18.

  The condensed water 11, 39, 40 and the battery cooling water 18 collected in the condensed water tank 14 are supplied to the fuel reforming system 2 as the reformed water 3 by the reformed water pump 25. For the reformed water 3, an activated carbon tower 26 and an ion exchange resin tower 27 are installed for removing substances that become poisoning components of the reforming catalyst contained in the reformed water system. According to the power generation system provided with the water treatment system as described above, it is possible to reduce or omit makeup water from outside the system system, which can contribute to the improvement of system efficiency.

  As described above, the battery cooling water system supplies the battery cooling water 18 to the fuel cell main body 5 by the battery cooling water pump 21, and the battery cooling water 18 exiting the fuel cell main body 5 is once stored in the condensed water tank 14. The circulation system is cooled by the heat exchanger 22 and returned to the fuel cell main body 5. In such a circulation system, if the conductivity of the battery cooling water 18 is increased, there is a possibility that a short circuit occurs in the fuel cell main body 5 to cause a decrease in the amount of power generation and further to stop power generation.

  In the case of the power generation system having the fuel reforming system 2 as shown in FIG. 2, there are a plurality of factors as follows. That is, in the anode 5a which is the fuel electrode of the fuel cell main body 5, a gas containing a large amount of carbon dioxide of several tens of percent comes into contact with the battery cooling water 18, and at this time, the carbon dioxide gas dissolves into the battery cooling water 18. .

  Further, since the anode exhaust gas 7 from the anode 5a of the fuel cell 5 and the combustion exhaust gas 15 of the reformer burner 12 contain carbon dioxide, naturally, the condensed water 11 and 39 obtained by cooling this also contain carbon dioxide. Will be included. Furthermore, ammonia produced by the reformer of the fuel reforming system 2, metal ions from pipes and containers used in the entire system system, and the like are eluted into the water. These carbon dioxide, ammonia, and metal ions are all factors that increase the conductivity in water.

  Therefore, as a technique for reducing the conductivity of battery cooling water, for example, in the fuel cell power generation system disclosed in Patent Document 1, an ion exchange resin tower filled with an ion exchange resin is provided. That is, in the technique described in Patent Document 1, the condensed water of the exhaust gas from the battery anode and the combustion exhaust gas from the reformer is sent to the ion exchange resin tower using a pump, and the ions are removed by the ion exchange resin to reduce the conductivity. Has been implemented.

  However, if the amount of carbon dioxide flowing into the battery cooling water 18 becomes too large, the conductivity reduction process using the ion exchange resin may not be in time. Therefore, in the fuel cell power generation system described with reference to FIG. 2, the condensed water 11, 39, 40 and the battery cooling water 18 are collectively stored in the condensed water tank 14 of the composite heat exchanger 13, and then the battery cooling water 18 is stored. This problem is avoided by providing the heat exchanger 22 and the ion exchange resin tower 24 only in one of the divided water systems 18a in two directions (for example, the technology of Japanese Patent Application No. 2006-8036).

  That is, in the technique of Japanese Patent Application No. 2006-8036, the ion-exchange resin tower 24 is installed in the battery cooling water system, and the activated carbon tower 26 and the ion-exchange resin tower 27 are installed in the reforming water system, so Purify separately. For this reason, the electrical conductivity of the battery cooling water 18 can be maintained at a low level, and deterioration of battery performance can be prevented.

Moreover, load suppression of the ion exchange resin 23 is realized by making the battery cooling water 18 into the diversion flows 18a and 18b. Furthermore, by installing the activated carbon tower 26 and the ion exchange resin tower 27 in the reformed water system, substances that become poisonous components of the reforming catalyst contained in the reformed water system can be removed.
JP 2006-40553 A

  However, the water treatment system adopted in the fuel cell power generation system of the above-mentioned Japanese Patent Application No. 2006-8036 has the following problems, which greatly imposes an economic burden on improving the quality of fuel cell cooling water and reforming water. Was. As a first problem, since the ion-exchange resin tower 24 is installed in the battery cooling water system and the activated carbon tower 26 and the ion-exchange resin tower 27 are installed in the reforming water system, independent water quality purification means are provided in each water system. As a result, the cost was increased.

  As a second problem, since the battery cooling water 18 is divided in two directions, the battery cooling water 18 passes through the ion exchange resin tower 24 only at a certain rate. Accordingly, if the condensed water 11, 39, 40 and the battery cooling water 18 accumulated in the condensed water tank 14 contain an unexpectedly large amount of impurities, it takes a long time to purify the water quality of the battery cooling water 18. It was to hang.

  As described above, in the conventional technique, the load of the ion exchange resin 23 is large, and it is difficult to use continuously for a long time. For this reason, it is necessary to frequently refill the ion exchange resin 23, which increases the economic burden. In order to solve this problem, a method of purifying only condensed water with an ion exchange resin as in the system described in Patent Document 1 is also conceivable. In this case, the condensed water is fed into the ion exchange resin tower. The pump for this purpose must be provided separately from the battery cooling water system, resulting in a complicated system and an increase in cost.

  As a third problem, an ion exchange resin used for water purification may be decomposed by an oxidizing agent such as dissolved oxygen in water to elute an organic sulfur compound. Since the organic sulfur compound is a poisoning component of the reforming catalyst, it causes deterioration of the reforming catalyst itself. That is, the ion exchange resin for removing the substance that reduces the electrical conductivity has been a factor of reducing the performance of the fuel reforming system. For this reason, when using an ion exchange resin, it was strongly requested to prevent the organic sulfur compound from flowing out.

  The present invention has been made in order to solve the above-described problems. The configuration of the water treatment system incorporated in the system is simplified, the load of the ion exchange resin is reduced and the life of the ion treatment resin is extended. An object of the present invention is to provide a fuel cell power generation system excellent in economic efficiency and reliability in which the outflow of sulfur compounds is prevented and the performance of the reforming catalyst is maintained.

  In order to achieve the above object, the present invention provides a fuel reforming system for producing a hydrogen-rich gas by a steam reforming reaction using a hydrocarbon fuel as a raw fuel, and a hydrogen-rich gas produced by the fuel reforming system as a fuel. Fuel cell power generation provided with a fuel cell main body for generating electric power by introducing oxygen in the intake air into the anode as an oxidizer and an operating temperature of the fuel cell main body to maintain the operating temperature of the fuel cell main body In the system, condensed water generating means for generating condensed water by cooling the exhaust gas discharged from the fuel reforming system or the fuel cell main body, and a battery cooling water tank for storing the battery cooling water exiting the fuel cell main body A condensed water tank for storing the condensed water generated by the condensed water generating means, a heat exchanger for cooling the condensed water stored in the condensed water tank, and the heat exchange An ion exchange resin column filled with a cation exchange resin for removing cations in the condensed water after cooling with the heat exchanger and an anion exchange resin for removing anions, And a pipe that joins the water exiting the ion exchange resin tower and the water exiting the cooling water tank and introduces the combined water as the battery cooling water into the fuel cell main body. And

  In the ion exchange resin tower according to the present invention, the cation exchange resin is disposed on the upstream side of the ion exchange resin tower, and the anion exchange resin is disposed on the downstream side of the ion exchange resin tower. It is characterized by being configured to water.

  In the present invention having the above-described configuration, only condensed water having a large amount of impurities harmful to the fuel cell is purified by an ion exchange resin tower, and then combined with water from a cooling water tank having relatively good water quality. Can be fed into the fuel cell body as battery cooling water. Accordingly, it is possible to introduce a good battery cooling water with a small amount of impurities and a small amount of water passing through the ion exchange resin. Further, since the temperature of water passed through the ion exchange resin by the heat exchanger is reduced to a temperature at which the ion exchange resin is hardly decomposed, high water quality can be maintained for a long time.

  Further, in the ion exchange resin tower of the present invention, the cation exchange resin is arranged on the upstream side, and the anion exchange resin is arranged on the downstream side and water is passed in the upward flow, so that the sulfur compound generated by the degradation decomposition of the cation exchange resin Can be captured by a downstream anion exchange resin, and sulfur compounds are not mixed into the reformed water.

  According to the fuel cell power generation system of the present invention, the ion exchange resin tower is provided downstream of the heat exchanger, the water exiting the ion exchange resin tower and the water exiting the cooling water tank are merged, and the merged water is By introducing the battery cooling water into the fuel cell main body, the conductivity of the battery cooling water can be kept low for a long period of time, and the sulfur-based compound is prevented from flowing into the reforming water. Maintains performance and contributes to improvement of economy and reliability.

(Representative embodiment)
[Constitution]
Hereinafter, a representative embodiment of a fuel cell power generation system according to the present invention will be described with reference to FIG. FIG. 1 shows a configuration diagram of this embodiment. In addition, the same code | symbol is attached | subjected regarding the member same as the prior art shown in FIG.

  The fuel cell package 1 shown in FIG. 1 includes a fuel reforming system 2, a fuel cell body 5, heat exchangers 8 and 16, a decarboxylation tower 19 and the like as main components. The basic structure of such a fuel cell package 1 is the same as that of the prior art of FIG. For this reason, overlapping parts are denoted by the same reference numerals, description thereof is omitted, and only differences are described.

  The feature of the configuration of the present embodiment is as follows. That is, a two-tank water tank container 43 is provided on the downstream side of the heat exchanger 16 and the decarboxylation tower 19. The water tank container 43 is a tank formed integrally by condensing the condensed water tank 14 and the battery cooling water tank 30 with a partition plate. A drain pipe 34 is attached to the lower part of the condensed water tank 14.

  The water levels of the condensed water tank 14 and the battery cooling water tank 30 are such that surplus water overflowing from the battery cooling water tank 30 is led to the condensate water tank 14, and surplus water overflowing from the condensate water tank 14 is discharged out of the system by the drain pipe 34. Is set to be. It should be noted that a fixed amount of pure water from which impurities have been removed in advance and whose conductivity has been reduced is supplied to each of the reservoirs of the tanks 14 and 30 before the power generation operation of the fuel cell power generation system.

  A heat exchanger 22 is provided on the downstream side of the condensed water tank 14, and an ion exchange resin tower 24 is disposed on the downstream side of the heat exchanger 22. The ion exchange resin tower 24 is filled with a cation exchange resin 23a having a crosslinking degree of 10% or more on the upstream side (lower side in FIG. 1), and the anion exchange resin 23b on the downstream side (upper side in FIG. 1). Is configured to allow water to flow in an upward flow.

  Furthermore, in this embodiment, the condensed water that has exited the condensed water tank 14 is 18c, and the water that has exited the battery cooling water tank 30 is 18d. Among these, the condensed water 18c is cooled via the heat exchanger 22, and after the ions are removed via the ion exchange resin tower 24, the condensed water 18c is piped so as to merge with the water 18d exiting the cooling water tank 30. Has been.

  This combined water 18e is introduced into the fuel cell body 5 as the battery cooling water 18. The battery cooling water 18 discharged from the fuel cell main body 5 passes through the decarbonation tower 19 to remove carbon dioxide in the moisture by gas-liquid contact with the cathode exhaust gas 17 and then to the battery cooling water tank 30. And come back. A battery cooling water pump 21 is provided between the position where the condensed water 18e exiting the ion-exchange resin tower 24 and the water 18d exiting the cooling water tank 30 are joined to the cooling water tank 30. Only one is arranged.

  Unlike the configuration of the conventional example shown in FIG. 2, the decarbonation tower 19 is installed not independently of the composite heat exchanger 13 but independently of the composite heat exchanger 13. There is no change in the point where the battery outlet water of water 18 is introduced. The decarbonation tower 19 is filled with a porous structure called terrarette made of a heat-resistant resin such as polypropylene or a metal such as a carbon steel stainless steel, or a multi-stage flat plate to widen the contact area between water and gas. Or is installed.

  By the way, in the ion exchange resin tower 24, the space downstream of the ion exchange resin layer 23b is a low space composed of a space not filled with the ion exchange resin so that the flow velocity is slower than that of other piping parts of the battery cooling water system. A flow velocity water area 33 is formed. Reformed water 3 for steam reforming of hydrocarbon fuel is supplied from the low flow rate water region 33 to the fuel reforming system 2 by a pump 25. However, the supply of the reforming water 3 is limited only when the battery cooling water 18 is circulating.

[Gas and water flow]
The flow of various gases and water in the fuel cell package 1 as described above is as follows. That is, the hydrocarbon fuel F is supplied to the fuel cell package 1 from a storage facility such as a pipeline or a gas cylinder.

As described in the conventional example of FIG. 2, the fuel F supplied to the fuel cell package 1 is desulfurized in the fuel reforming system 2 and then mixed with the vaporized reforming water 3 to form a steam reforming reaction, Converted to hydrogen-rich reformed gas 4 containing methane, CO, carbon dioxide (CO ₂ ), etc. whose CO concentration is reduced below the limit value of the battery by carbon monoxide (CO) modification reaction and CO selective oxidation reaction, etc. Is done. The reformed gas 4 is introduced into the anode 5 a of the fuel cell body 5, and the hydrogen is consumed by power generation together with oxygen in the atmosphere supplied to the fuel cell body 5 cathode 5 b by the air blower 6. In the fuel reforming system 2, the reformed gas condensed water 32 is obtained by cooling the process gas before being introduced into the CO selective oxidizer. Sent to.

  The anode exhaust gas 7 not consumed by the fuel cell main body 5 anode 5a is cooled by heat exchange with the exhaust heat recovery circulating water 10a introduced from the hot water tank 9 in the heat exchanger 8, and the anode exhaust gas condensed water 11 is removed. After that, the fuel is introduced into the fuel inlet of the reformer burner 12, burned with air (not shown) supplied from the outside of the fuel cell package 1, and used as a heat source for the steam reforming reaction. The anode exhaust gas condensed water 11 generated by the heat exchanger 8 is sent to a condensed water tank 14 which is a part of the water tank container 13. Further, the combustion exhaust gas 15 of the reformer burner 12 is sent to the heat exchanger 16.

  On the other hand, the cathode exhaust gas 17 in which the oxygen in the fuel cell body 5 cathode 5b is consumed and the oxygen concentration is reduced from the atmosphere is led to the lower part of the decarbonation tower 19 and the battery cooling water 18 introduced from the upper part of the decarbonation tower 19 The carbon dioxide gas dissolved in the battery cooling water 18 is reduced by flowing in the counterflow. Thereafter, the cathode exhaust gas 17 is sent to the heat exchanger 16 together with the combustion exhaust gas 15.

  Both the combustion exhaust gas 15 and the cathode exhaust gas 17 sent to the heat exchanger 16 are cooled by heat exchange with the exhaust heat recovery circulating water 10b introduced from the heat exchanger 22, and the combustion exhaust gas condensate from each gas 15,17. 39, the cathode exhaust gas 40 is removed. These condensed waters 39 and 40 are cooled and condensed by the heat exchanger 16 and flow into the condensed water tank 14. Further, the exhaust gases 15 and 17 after the condensed water 39 and 40 are removed are discharged from the composite heat exchanger 13 to the atmosphere.

  As described above, the condensed water tank 14 is supplied with the reformed gas condensed water 32 obtained by cooling the reformed gas 4, the anode exhaust gas condensed water 11 obtained by cooling the battery anode exhaust gas 7, and the combustion exhaust gas 15. And the condensed water 39 and 40 obtained by cooling the battery cathode exhaust gas 17 with the heat exchanger 16 are stored.

  The condensed water 11, 32, 39, 40 stored in the condensed water tank 14 is sent to the heat exchanger 22 as condensed water 18 c, and heat exchange with the exhaust heat recovery circulating water 10 a introduced from the heat exchanger 8 is performed. After the temperature is reduced by this, the ion exchange resin tower 24 is supplied. Excess water in the condensed water tank 14 is discharged from the drain pipe 34 to the outside of the fuel cell package 1 system.

  Further, when the condensed water 18c in the condensed water tank 14 is insufficient, the reformed gas condensed water 32 is introduced from the fuel reforming system 2 so as to compensate for this. However, the reformed gas condensed water 32 is not introduced into the condensed water tank 14 unless the condensed water 18c stored in the condensed water tank 14 is insufficient. It may be discharged out of the system.

  The condensed water 18c from the condensed water tank 14 supplied to the ion exchange resin tower 24 via the heat exchanger 22 passes through the cation exchange resin 23a and the anion exchange resin 23b sequentially in an upward flow, Cations and anions are removed to improve water quality. The condensed water 18c that has exited the ion exchange resin tower 24 is merged with the water 18d that has exited the cooling water tank 30, and the merged water 18e becomes the battery cooling water 18 and is introduced into the fuel cell body 5. The fuel cell main body 5 is maintained at an optimum operating temperature by the circulation of the battery cooling water 18. Note that the reforming water 3 for steam reforming of hydrocarbon fuel is supplied to the fuel reforming system 2 from the low flow velocity water region 33 in the ion exchange resin tower 24 by the pump 25.

  The battery cooling water 18 exiting the fuel cell main body 5 is cooled by heat exchange with the exhaust heat recovery circulating water 10b introduced from the heat exchanger 16 in the heat exchanger 36, and then the cathode exhaust gas in the decarbonation tower 19. The dissolved carbon dioxide gas is reduced by gas-liquid contact with 17. Thereafter, the battery cooling water 18 exiting the decarbonation tower 19 is stored in a cooling water tank 30 that is a part of the water tank container 13. In addition, the excess water of the battery cooling water tank 30 overflows to the condensed water tank 14 side.

[Function and effect]
The operational effects of the present embodiment as described above are as follows. That is, the condensed water 18c stored in the condensed water tank 14 contains a large amount of impurities that are harmful to the fuel cell body 5, and is purified by the ion exchange resin tower 24. The water 18 d from the good cooling water tank 30 is merged and supplied to the fuel cell main body 5.

  Therefore, the water 18d exiting from the cooling water tank 30 does not pass through the ion exchange resin tower 24, reduces the water flow to the ion exchange resin tower 24, and reduces the burden on the ion exchange resins 23a and 23b. be able to. Moreover, regarding the battery cooling water 18 (merged water 18e) to be introduced into the fuel cell main body 5, a good water quality with few impurities can be ensured. Therefore, the conductivity of the battery cooling water 18 can be kept low for a long period of time, and the reliability is improved.

  Moreover, in this embodiment, since the temperature of the condensed water 18c passed to the ion exchange resin tower 24 by the heat exchanger 22 is reduced, the decomposition of the ion exchange resins 23a and 23b hardly occurs. For this reason, the ion exchange resin tower 24 can maintain high performance over a long period of time. Furthermore, since the battery cooling water 18 is made to flow by the single battery cooling water pump 21 between the system from the confluence | merging point used as the confluence | merging water 18e to the cooling water tank 30, a some pump becomes unnecessary. The system can be simplified.

  In addition, in the present embodiment, the water discharged from the ion exchange resin 23b in the ion exchange resin tower 24 is supplied to the fuel reforming system 2 as the reformed water 3, so that the battery cooling is performed by the single ion exchange resin tower 24. It is possible to improve the water quality of both the water system and the reformed water system, and not only simplification of the system but also maintenance management such as replacement of the ion exchange resins 23a and 23b is facilitated, which is economically advantageous.

  In addition, the reformed water 3 exiting the ion exchange resin tower 24 is led from the low flow velocity water region 33 formed in the ion exchange resin tower 24, so that it is gently led to the fuel reforming system 2, and the battery The influence which the pulsation resulting from the cooling water pump 21 etc. has on the reforming water 3 supply can be suppressed. For this reason, there is an advantage that a stable operation of the fuel cell power generation system can be realized.

  Further, in the present embodiment, the carbon dioxide gas in the outlet cooling water of the fuel cell main body 5 is removed by gas-liquid contact with the cathode exhaust gas 17 in the decarbonation tower 19, so that the cathode exhaust gas 17 gas having a lower oxygen concentration than air. Can be decarboxylated in water. Therefore, it becomes possible to introduce the battery cooling water 18 with little dissolved oxygen into the fuel cell main body 5. In addition, carbonate ions and dissolved oxygen in the battery cooling water 18 overflowing from the battery cooling water tank 30 side to the condensed water tank 14 side can be suppressed. Thereby, while reducing the load of the ion exchange resin 23a, 23b with which the ion exchange resin tower 24 was filled, decomposition | disassembly of the ion exchange resin 23a, 23b by oxidation can be suppressed.

  Further, in the fuel cell power generation system of the present embodiment, the water level is set so that surplus water in the cooling water tank 30 is guided to the condensed water tank 14, so the amount of condensed water 18 c to be passed to the ion exchange resin tower 24. Adjustment is easy. As a result, the amount of battery cooling water supplied to the fuel cell main body 5 can be ensured, and the operation of the fuel cell power generation system can be further stabilized.

  In this embodiment, since the ion exchange resin tower 24 is filled with a cation exchange resin 23a having a degree of crosslinking of 10% or more, it is oxidized or oxidized as compared with a general cation exchange resin having a degree of crosslinking of 8%. Degradation due to thermal decomposition is slow, and from this point of view, stable operation of the fuel cell power generation system can be realized.

  Furthermore, in the ion exchange resin tower 24, the cation exchange resin 23a is arranged upstream and the anion exchange resin 23b is arranged downstream to constitute a water purification device that allows water to flow in an upward flow. Sulfur compounds produced by degradation decomposition can be captured by a downstream anion exchange resin. For this reason, the sulfur compound that is a poisoning component of the reforming catalyst is not mixed into the reforming water 3, and the reforming catalyst can be reliably protected from sulfur poisoning. In addition, since an upward flow is used in the ion exchange resin tower 24, the cation exchange resin 23a having a heavy specific gravity is not mixed with the downstream anion exchange resin 23b, and high reliability can be maintained. .

  Further, in the present embodiment, the reforming water 3 is supplied to the fuel reforming system 2 only when the battery cooling water 18 is circulating, so that it is branched to the battery cooling water system downstream of the ion exchange resin tower 24. The water is always present at the supply position of the reforming water 3 installed in the above, that is, the low-flow-rate water region 33, and the reforming water 3 can be reliably supplied.

(Other embodiments)
The present invention is not limited to the above embodiment, and the configuration and arrangement of each member can be appropriately changed. For example, in the above embodiment, the low flow rate water region 33 is replaced with the ion exchange resin layer 23b. However, instead of the inside of the ion exchange resin tower 24, a tank provided independently outside the tower 24 may be used as the low-flow-rate water area. Moreover, in the said embodiment, although the condensed water tank 14 and the cooling water tank 30 were integrated and comprised with the water tank container 13, you may arrange | position a separate tank and connect both with piping, or a decarboxylation tower 19 and the condenser 16 may be integrated with the water tank container 13.

  In addition, the heat utilized in this embodiment is obtained by each heat recovery from the heat exchangers 8, 16, 22 of the exhaust heat recovery circulating water 10 a, 10 b introduced from the hot water storage tank 9 into the fuel cell package 1. . Further, in the above embodiment, the heat supply system using water to the hot water tank 9 which has many application examples is taken up. However, the supply form of heat to the use destination is not limited to the hot water tank 9, and the waste water is discharged. The medium flowing through the heat recovery circulation system is not limited to water.

The block diagram of typical embodiment of this invention. The block diagram of the conventional fuel cell power generation system.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Fuel cell package 2 ... Fuel reforming system 3 ... Reformed water 4 ... Reformed gas 5 ... Fuel cell main body 5a ... Anode 5b ... Cathode 6 ... Air blower 7 ... Anode exhaust gas 8, 16, 22, 36 ... Heat exchange Apparatus 9 ... Hot water storage tank 10, 10a ... Waste heat recovery circulating water 11 ... Anode exhaust gas condensed water 12 ... Reformer burner 13 ... Combined heat exchanger 14 ... Condensed water tank 15 ... Combustion exhaust gas 17 ... Anode exhaust gas 18 ... Battery cooling water 18c ... Condensed water 18d ... Cooling water 18e exiting the battery cooling water tank ... Combined water 19 ... Decarboxylation tower 21 ... Battery cooling water pump 23 ... Ion exchange resin 23a ... Cation exchange resin 23b ... Anion exchange resins 24, 27 ... ion exchange resin tower 25 ... reformed water pump 26 ... activated carbon tower 30 ... battery cooling water tank 32 ... reformed gas condensate 33 ... low flow rate water area 34 ... drain pipe 38 ... air filter 39 ... combustion exhaust gas Condensed water 40 ... cathode exhaust condensed water 43 ... water tank vessel

Claims (9)

A fuel reforming system for producing a hydrogen-rich gas by a steam reforming reaction using a hydrocarbon-based fuel as a raw fuel; a hydrogen-rich gas produced by the fuel reforming system as a fuel; and an anode using oxygen in the air as an oxidant In a fuel cell power generation system provided with a fuel cell main body that takes in and generates electric power, and a battery cooling water system for flowing battery cooling water for maintaining the operating temperature of the fuel cell main body,
A condensed water generating means for cooling the exhaust gas discharged from the fuel reforming system or the fuel cell main body to generate condensed water;
A battery cooling water tank for storing the battery cooling water exiting the fuel cell main body;
A condensed water tank for storing the condensed water generated by the condensed water generating means;
A heat exchanger for cooling the condensed water stored in the condensed water tank;
Ions filled with a cation exchange resin for removing cations in the condensed water after cooling with the heat exchanger and an anion exchange resin for removing anions downstream of the heat exchanger An exchange resin tower,
The fuel is characterized in that the water exiting the ion-exchange resin tower and the water exiting the cooling water tank are merged and piped to introduce the merged water into the fuel cell body as the battery cooling water. Battery power generation system.   The ion exchange resin tower is configured such that the cation exchange resin is arranged on the upstream side of the ion exchange resin tower and the anion exchange resin is arranged on the downstream side of the ion exchange resin tower so that water flows in an upward flow. The fuel cell power generation system according to claim 1.   A pump for the battery cooling water is provided between the battery cooling water system from the position where the combined water of the water exiting the ion exchange resin tower and the water exiting the cooling water tank joins to the cooling water tank. The fuel cell power generation system according to claim 1 or 2, wherein one fuel cell is installed.   A pipe is provided so that water exiting the ion exchange resin portion filled in the ion exchange resin tower is supplied to the fuel reforming system as water for steam reforming of the hydrocarbon fuel. The fuel cell power generation system according to any one of claims 1 to 3. A low-flow-rate water area in which the flow rate is slower than the flow rate of the battery cooling water in the pipe of the battery cooling water system, downstream of the ion-exchange resin in the ion-exchange resin tower or downstream of the ion-exchange resin tower,
5. The fuel cell power generation system according to claim 4, wherein water discharged from the low flow rate water region is piped so as to be supplied to the fuel reforming system as water for steam reforming of the hydrocarbon fuel. .   Incorporating the battery cooling water from the fuel cell body and the exhaust gas from the cathode of the fuel cell body, the carbon dioxide gas present in the battery cooling water is removed by gas-liquid contact with the exhaust gas from the cathode. The fuel cell power generation system according to claim 1, further comprising a decarboxylation device.   The fuel cell power generation system according to any one of claims 1 to 6, wherein the water levels of the two tanks are set so as to guide surplus water from the cooling water tank to the condensed water tank.   The fuel cell power generation system according to any one of claims 1 to 7, wherein the cation exchange resin is a cation exchange resin having at least a crosslinking degree of 10% or more.   4. The apparatus according to claim 3, wherein water for steam reforming of the hydrocarbon fuel is supplied to the fuel reforming system only when the battery cooling water is circulating in the battery cooling water system. The fuel cell power generation system of any one of -8.

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