JP2009245702A - Water processing unit for fuel cell power generation system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a water processing unit for a fuel cell power generating system, which can deionize condensed water generated in the fuel cell power generating system by using an electric deionizer and collecting, from thereby generated concentrated water, carbon dioxide that is highly useful as an inert gas. <P>SOLUTION: The water processing unit for a fuel cell power generating system includes the electric deionizer 31 deionizing condensed water collected from the exhaust gas discharged from a fuel cell body 1 and/or a reformer 3, and carbon dioxide collecting means is formed along a flow path L26 on the concentrated water discharge side of the electric deionizer 31. Preferably, heating means 34 is disposed between the electric deionizer and the carbon dioxide collecting means. Preferably, the carbon dioxide collecting means is composed of a gas-liquid separator 32 and a carbon dioxide collecting vessel 33 for collecting carbon dioxide resulting from gas-liquid separation by the gas-liquid separator 32. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a water treatment device for a fuel cell power generation device including an electric deionization device.

  Fuel cell exhaust gas discharged from the cathode outlet of the fuel cell body and combustion exhaust gas discharged from the combustion section of the reformer contain moisture. And in order to maintain the water self-supporting in the system of the fuel cell power generation system (the state where the operation is continued without accepting the makeup water from the outside), the condensed water is recovered from these exhaust gases and subjected to deionization treatment. Reuse is generally done.

As a method for deionizing condensate water, as disclosed in Patent Document 1 below, an attempt has been made in recent years to deionize condensate using an electric deionizer.
JP 2001-232394 A

  The concentrated water discharged from the electric deionizer contains carbon dioxide in the condensed water that has been ionized and separated and concentrated. The supersaturated carbonate ions or bicarbonate ions are dissociated as gaseous carbon dioxide. For this reason, gaseous carbon dioxide is discharged from the concentrated water discharge side of the electric deionizer while being mixed with the concentrated water. The carbon dioxide discharged in a state of being mixed with the concentrated water is a high-purity gaseous carbon dioxide that is saturated and dissociated by carbonate ions and bicarbonate ions in the water, and therefore has high utility value as an inert gas.

  However, conventionally, carbon dioxide contained in the concentrated water has been exhausted into the atmosphere, and no attempt has been made to recover these carbon dioxide.

  Accordingly, an object of the present invention is to decondense the condensed water generated in the fuel cell power generation system with an electric deionization device, and to use carbon dioxide, which has a high utility value as an inert gas, from the generated concentrated water. Is to provide a water treatment device for a fuel cell power generator.

In order to achieve the above object, a water treatment device for a fuel cell power generator according to the present invention is an electric deionization device for deionizing condensed water recovered from exhaust gas discharged from a fuel cell main body and / or reforming device. A water treatment device for a fuel cell power generator, comprising:
Carbon dioxide recovery means is provided in the flow path on the concentrated water discharge side of the electric deionizer.

  In the present invention, carbon dioxide collecting means is provided in the flow path on the concentrated water discharge side of the electric deionizer, so that high-purity carbon dioxide that can be effectively used as a purge gas for the fuel cell main body or reformer is obtained. It can be recovered.

  In the water treatment apparatus for a fuel cell power generator according to the present invention, it is preferable that a heating means is disposed between the electric deionization apparatus and the carbon dioxide recovery means. By heating the concentrated water, the dissolved amount of carbon dioxide is reduced and the carbon dioxide dissolved in the concentrated water is gasified and released, so that the carbon dioxide recovery efficiency is improved.

  The carbon dioxide recovery means of the water treatment device for a fuel cell power generator according to the present invention includes a gas-liquid separator and a carbon dioxide recovery container that recovers the carbon dioxide gas-liquid separated by the gas-liquid separator. It is preferable.

  It is preferable that the volume of the carbon dioxide recovery container of the water treatment device for a fuel cell power generator according to the present invention can vary depending on the internal pressure. According to this aspect, in the process of recovering carbon dioxide, gas such as air is less likely to be mixed in the carbon dioxide recovery container, and carbon dioxide with higher purity can be recovered.

  According to the present invention, by providing the carbon dioxide recovery means in the flow path on the concentrated water discharge side of the electric deionizer, high purity dioxide that can be effectively used as the purge gas for the fuel cell main body or reformer. Carbon can be recovered.

  Hereinafter, a first embodiment of a water treatment apparatus for a fuel cell power generator according to the present invention will be described with reference to the drawings. FIG. 1 is a schematic configuration diagram of a fuel cell power generator incorporating the water treatment device for the fuel cell power generator.

  In FIG. 1, reference numeral 1 denotes a fuel cell main body, which is a cooling system having an anode electrode 1a and a cathode electrode 1b sandwiching an electrolyte 1c, and a cooling pipe disposed each time a plurality of unit cells made of these are stacked. 1d.

A reformed gas supply line L1 extending from the reformer 3 is connected to the reformed gas supply side of the anode electrode 1a. The reformed gas supply line L1 is provided with a reformed gas drain trap Q1, and the reformed gas condensate water supply line L2 extends from the condensate storage part of the reformed gas drain trap Q1 to decarboxylate. It is connected to the device 5.
An anode off-gas discharge line L3 extends from the anode off-gas discharge side of the anode electrode 1a, and the tip side thereof is connected to the combustion fuel supply line L12. Further, an anode offgas drain trap Q2 is disposed in the middle of the anode offgas discharge line L3, and the anode offgas condensed water supply line L4 extends from the condensate storage part of the anode offgas drain trap Q2. 5 is connected.

An air supply line L5 extending from an air supply source is connected to the air supply side of the cathode electrode 1b. The humidifier 2 is disposed in the air supply line L5.
A cathode offgas discharge line L6 extends from the cathode air discharge side of the cathode electrode 1b and is connected to the water tank 4. A cathode offgas heat exchanger Q3 is disposed in the cathode offgas discharge line L6.

A battery coolant supply line L7 extending from the battery coolant tank 12 is connected to the coolant supply side of the cooling system 1d.
A battery cooling water discharge line L8 extends from the cooling water discharge side of the cooling system 1d and is connected to the battery cooling water tank 12.

  The reformer 3 includes a reforming catalyst layer group 3a filled with a reforming catalyst such as a steam reforming catalyst, and a combustion section 3b in which a burner is arranged, and burns combustion fuel with the burner. The reforming catalyst layer group 3a is heated by the combustion heat and combustion exhaust gas generated at the time. In this embodiment, the reformer is intended to be an integrated reformer filled with a plurality of reforming catalysts. However, the invention uses a reformer composed of a plurality of reactors. Does not prevent it from being done.

The raw material supply line L9 extending from the raw fuel source and the reforming water supply line L10 extending from the battery cooling water tank 12 are connected to the reforming raw material input side of the reforming catalyst layer group 3a.
A reformed gas supply line L1 extends from the reformed gas discharge side of the reformed catalyst layer group 3a and is connected to the anode electrode 1a.

A combustion fuel supply line L12 and a combustion air supply line L11 are connected to the combustion fuel introduction port side of the combustion unit 3b, and the combustion fuel and the combustion air are supplied to the burner disposed in the combustion unit 3b. It is configured to be able to. The anode offgas discharge line L3 and the raw fuel supply line L9 are connected to the upstream side of the combustion fuel supply line L12.
A combustion exhaust gas line L13 extends from the combustion exhaust gas exhaust side of the combustion section 3b and is connected to the decarbonation device 5. A combustion exhaust gas heat exchanger Q4 is disposed in the combustion exhaust gas line L13.

  The decarbonation device 5 is disposed adjacent to the upper portion of the water tank 4 and communicates via the drain port 6. A reformed gas condensate supply line L2, an anode off-gas condensate supply line L4, a combustion exhaust gas line L13, and a concentrated water discharge line L26, which will be described later, are connected to the upper portion of the decarboxylation device 5. Further, an exhaust line L17 extends from the decarboxylation device 5.

  The decarbonation device 5 is not particularly limited, and a device that can degas by condensing condensed water and decarbonation air to diffuse carbon dioxide in the condensed water in the air can be preferably used. The deaeration device having such a configuration includes a deaeration part filled with a SUSCH ring or the like, supplies condensed water to the upper part of the deaeration part, and supplies decarbonation air from the lower part of the deaeration part. Supplying and condensing water by gravity falling, contacting with decarbonation air and decarboxylation treatment, for example, a porous material as disclosed in JP-A-2007-323969 The degassing part in which the inclined plate is arranged is provided, decarbonation air is circulated from the lower side of the inclined plate to the upper side, and condensed water is allowed to flow downward from the upper side of the inclined plate, An example of such a structure that decarboxylates the condensed water is given as an example.

  The water tank 4 is connected to a cathode offgas discharge line L6 and a battery cooling water overflow line L18 extending from the battery cooling water tank 12. A tank water overflow line L19 extends on the side wall of the water tank 4 so that the water level in the tank does not exceed a certain level. A recovered water extraction line L20 extends from the lower part of the water tank 4 and is connected to the battery cooling water tank 12. The water treatment apparatus 30 of the present invention is disposed in the recovered water extraction line L20. In some cases, a pump for removing recovered water may be connected to the recovered water extraction line L20 before the water treatment device 30.

  This water treatment device 30 is mainly composed of an electric deionization device 31, a gas-liquid separator 32, and a carbon dioxide recovery container 33.

  The electric deionization device 31 has a demineralization chamber and a concentration chamber partitioned by an ion exchange membrane between an anode and a cathode, and the demineralization chamber is filled with an ion exchange resin. A conventionally known electric deionization apparatus can be used.

  And the front-end | tip of the recovery water extraction line L20 is the to-be-processed water supply line L21 connected to the demineralization chamber of the electric deionization apparatus 31, and the concentrated water supply line L22 connected to the concentration chamber of the electric deionization apparatus 31. It is branched to.

In the present invention, a filter, a metal ion removal device, or the like may be disposed between the electric deionization device 31 and the recovery tank 4, and a filter or a metal ion removal device may be disposed from the upstream side. preferable.
By disposing the filter, impurities such as soot and dust contained in the recovered water collected in the water tank 4 can be removed, and soot and the like can be prevented from adhering to the electric deionizer 31. The filter is not particularly limited, and a metal removal filter, a fine particle removal filter and the like are preferable.
By disposing the metal ion removing device, the metal ions eluted from the piping and the like can be removed, so that the load on the electric deionization device 31 can be further reduced and the life of the device can be prolonged. There is no limitation in particular as a metal ion removal apparatus, A chelate resin etc. are mentioned preferably.

A deionized water supply line L23 extends from the deionized water discharge side of the electric deionizer 31 and is connected to the battery cooling water tank 12. A water treatment resin such as an ion exchange resin may be arranged in the deionized water supply line L23. By disposing the water treatment resin, ions that could not be processed by the electric deionization device 31 can be removed, so that deionized water with further reduced ions can be supplied to the battery cooling water tank 12.
A concentrated water extraction line L24 extends from the concentrated water discharge side of the electric deionizer 31 and is connected to the gas-liquid separator 32.

  The gas-liquid separator 32 is not particularly limited as long as it is a device that recovers gas components by gas-liquid separation of gaseous carbon dioxide mixed with concentrated water or carbon dioxide dissolved in the concentrated water. Absent. For example, as shown in FIG. 2, the leading end of the concentrated water extraction line L24 extends to the water stored in the gas-liquid separator 32, and the mixture of the liquid component and the gas component is dropped into the water and bubbled. Then, the liquid component contained in the composite is dropped into water, and a device that collects gaseous carbon dioxide that does not contain the liquid component, or a mixture of the liquid component and the gas component as shown in FIG. An apparatus for recovering gaseous carbon dioxide that does not contain a liquid component by bringing it into contact with each other and condensing the liquid component contained in the hybrid is exemplified.

A concentrated water discharge line L26 extends from the lower part of the gas-liquid separator 32 and is connected to the decarboxylation device 5. The concentrated water discharge line L26 is preferably provided with a solenoid valve, a drain trap, or the like so that the water level in the gas-liquid separator 32 is maintained within a certain range.
A carbon dioxide recovery line L25 extends from the upper part of the gas-liquid separator 32 and is connected to the carbon dioxide recovery container 33. The carbon dioxide recovery container 33 is provided with a carbon dioxide extraction line (not shown).

  The carbon dioxide recovery container 33 is not particularly limited as long as it is a container that can recover carbon dioxide. For example, a container whose volume can be changed according to the internal pressure as shown in FIGS.

  A carbon dioxide recovery container 33a shown in FIG. 4 is a container in which a piston 41 is disposed in a cylinder 40. When carbon dioxide is supplied into the cylinder 40 from a carbon dioxide inlet 42, the piston 41 is pushed up. The internal volume is changed. In this embodiment, the carbon dioxide inlet 42 is configured in common with the carbon dioxide outlet. However, the carbon dioxide outlet and the inlet are separately provided on the side wall of the cylinder 40. Also good.

  A carbon dioxide recovery container 33 b shown in FIG. 5 is a container in which a bag 51 made of a gas-impermeable material is disposed in a housing 50, and carbon dioxide is supplied into the bag 51 from a carbon dioxide inlet 52. Then, the inner volume is freely changed within the volume of the housing 50. In this embodiment, the carbon dioxide inlet 52 is configured in common with the carbon dioxide outlet. However, the carbon dioxide outlet and the inlet may be separately provided on the side wall of the housing 50. Good. By using such a container whose volume can vary according to the internal pressure, the volume before collecting the gaseous carbon dioxide contained in the concentrated water is made zero, and then the carbon dioxide is recovered, Gases such as air are less likely to be mixed in the process of recovering carbon dioxide, and carbon dioxide with higher purity can be recovered.

  In this embodiment, the gas-liquid separator 32 and the carbon dioxide recovery container 33 are separately provided. However, the carbon dioxide recovery container 33 is connected to the upper part of the gas-liquid separator 32, and An apparatus in which the gas-liquid separator 32 and the carbon dioxide recovery container 33 are integrated may be used. An example of such an apparatus is shown in FIG.

  In FIG. 6, the lower portion of the housing 60 forms a concentrated water storage portion 61, and a concentrated water extraction line L <b> 24 is connected to the side wall of the storage portion 61. A concentrated water discharge line L26 is connected to the side wall of the storage unit 61 and above the concentrated water extraction line L24. In this concentrated water discharge line L26, an electromagnetic valve V1 is disposed, and the electromagnetic valve V1 is opened and closed according to the output from the float switch 65 disposed in the storage unit 61, so that the water level in the storage unit 61 is constant. Configured to maintain range. A piston 62 is disposed in the upper part of the storage unit 61, and a carbon dioxide outlet 64 is provided in a side wall below the position where the piston 62 is disposed. When the concentrated water containing gaseous carbon dioxide is supplied from the concentrated water drawing line L24, bubbling is performed in the storage unit 61, and concentrated water that is a liquid component is recovered in the storage unit 61. Further, the gaseous carbon dioxide is collected in the space 63 above the reservoir 61 while pushing up the piston 62. That is, the storage unit 61 forms a “gas-liquid separator”, and the space 63 above the storage unit 61 forms a “carbon dioxide recovery container”.

  Next, the operation of the fuel cell power generator configured as described above will be described.

  In the reformer 3, the raw fuel supplied from the raw fuel supply line L9 is mixed with the reformed water supplied from the reformed water supply line L10, supplied to the reforming catalyst layer group 3a, and steam reformed. A reformed gas rich in hydrogen is generated by a chemical reaction including a quality reaction. Since the steam reforming reaction is an endothermic reaction, combustion fuel is supplied from the combustion fuel supply line L12 and combustion air from the combustion air supply line L11 to the combustion unit 3b of the reformer 3, and these are combusted. Then, the reforming catalyst layer group 3a is heated. At the start of starting the fuel cell power generator, the raw fuel supplied from the raw fuel supply line L9 is mainly used as the combustion fuel, the combustion state in the combustion section 3b is stabilized, and the reforming system When the catalyst layer group 3a is sufficiently heated, anode off gas is mainly used.

  The reformed gas generated by the reformer 3 is supplied to the anode electrode 1a through the reformed gas supply line L1. Condensed water contained in the reformed gas is recovered by the reformed gas drain trap Q1 disposed in the middle of the reformed gas supply line L1, and supplied to the decarbonation device 5 through the reformed gas condensed water supply line L2. Is done.

  In the fuel cell main body 1, the reformed gas supplied to the anode electrode 1a and the air supplied to the cathode electrode 1b are electrochemically reacted at the interface of the electrolyte 1c to generate power, and this generated output is supplied to the power system. .

  The cathode offgas discharged from the cathode electrode 1b is cooled by the cathode offgas heat exchanger Q3 and supplied to the water tank 4 through the cathode offgas discharge line L6 together with the cathode offgas condensed water and the cathode gas.

  The anode off gas discharged from the anode electrode 1a is supplied to the combustion unit 3b through the anode off gas discharge line L3 and used as a combustion fuel. The condensed water contained in the anode off gas is recovered by an anode off gas drain trap Q2 disposed in the middle of the anode off gas discharge line L3, and is supplied to the decarbonation device 5 through the anode off gas condensed water supply line L4.

  The combustion exhaust gas discharged from the combustion unit 3b of the reformer 3 is cooled by the combustion exhaust gas heat exchanger Q4 and supplied to the decarbonation device 5 together with the combustion exhaust gas.

  The condensed water collected in the water tank 4 is sent to the water treatment device 30, deionized by the electric deionization device 31, and then deionized water discharged from the demineralization chamber is supplied with deionized water. It is sent to the battery cooling water tank 12 through the line L23 and used for battery cooling water, humidified water, reforming water, and the like.

  On the other hand, the concentrated water discharged from the concentration chamber of the electric deionizer 31 is contained in a state where carbon dioxide in the condensed water is ionized and separated and concentrated. The supersaturated carbonate ions or bicarbonate ions are dissociated as gaseous carbon dioxide.

  Conventionally, carbon dioxide mixed with concentrated water or carbon dioxide dissolved in concentrated water is exhausted to the atmosphere as it is, for example, by refluxing concentrated water to a decarboxylation device. Then, the concentrated water discharged from the concentration chamber of the electric deionizer 31 is introduced into the gas-liquid separator 32, and the carbon dioxide mixed with the concentrated water or the carbon dioxide dissolved in the concentrated water is removed. The carbon dioxide is recovered in the carbon dioxide recovery container 33.

  Since carbon dioxide discharged in a state of being mixed with concentrated water is high-purity gaseous carbon dioxide that is saturated and dissociated with carbonate ions and bicarbonate ions in water, the carbon dioxide recovered in the carbon dioxide recovery container 33 is It can be effectively used as a purge gas for the fuel cell body 1 and the reformer 3.

  In FIG. 7, the schematic block diagram of the fuel cell power generator incorporating the water treatment apparatus for fuel cell power generators of 2nd embodiment of this invention is shown. In addition, the same code | symbol is attached | subjected to the location substantially the same as said 1st embodiment, and the description is abbreviate | omitted.

  The water treatment device 30 ′ of this embodiment is mainly composed of an electric deionization device 31, a gas-liquid separator 32, a carbon dioxide recovery container 33, and a heating means 34. And the said heating means 34 is arrange | positioned on the concentrated water drawing line L24. The heating means 34 is not particularly limited as long as it can heat concentrated water, and a heater or the like is preferable.

  In this embodiment, since the heating means 34 is disposed in front of the gas-liquid separator 32, the concentrated water can be heated and introduced into the gas-liquid separator 32. By heating the concentrated water, the dissolved amount of carbon dioxide is reduced and the carbon dioxide dissolved in the concentrated water is gasified and released, so that the carbon dioxide recovery efficiency in the carbon dioxide recovery container 33 is improved. .

It is a schematic block diagram of the fuel cell power generator incorporating the water treatment apparatus for fuel cell power generators of the first embodiment of the present invention. It is a schematic block diagram of one Embodiment of the gas-liquid separator used for the water treatment apparatus for fuel cell power generators of this invention. It is a schematic block diagram of other embodiment of the same gas-liquid separator. It is a schematic block diagram of one Embodiment of the carbon dioxide collection container used for the water treatment apparatus for fuel cell power generators of this invention. It is a schematic block diagram of other embodiment of the carbon dioxide collection container. It is a schematic block diagram of the apparatus which integrated the gas-liquid separator and the carbon dioxide collection container. It is a schematic block diagram of the fuel cell power generator incorporating the water treatment apparatus for fuel cell power generators of 2nd embodiment of this invention.

Explanation of symbols

1: Fuel cell body 1a: Anode electrode 1b: Cathode electrode 1c: Electrolyte 1d: Cooling system 2: Humidifier 3: Reforming device 3a: Reforming system catalyst layer group 3b: Combustion unit 4: Water tank 5: Decarbonation device 6: Drain port 12: Battery cooling water tank 30, 30 ': Water treatment device 31: Electric deionization device 32: Gas-liquid separators 33, 33a, 33b: Carbon dioxide recovery vessel 34: Heating means L1: Reformed gas Supply line L2: Reformed gas condensate supply line L3: Anode offgas discharge line L4: Anode offgas condensate supply line L5: Air supply line L6: Cathode offgas discharge line L7: Battery cooling water supply line L8: Battery cooling water discharge line L9: Raw fuel supply line L10: Reformed water supply line L11: Combustion air supply line L12: Combustion fuel supply line L13: Combustion exhaust gas line L17: Exhaust line L18: battery cooling water overflow line L19: tank water overflow line L20: recovered water extraction line L21: treated water supply line L22: concentrated water supply line L23: deionized water supply line L24: concentrated water extraction line L25: dioxide Carbon recovery line L26: concentrated water discharge line Q1: reformed gas drain trap Q2: anode offgas drain trap Q3: cathode offgas heat exchanger Q4: combustion exhaust gas heat exchanger

Claims (4)

A water treatment device for a fuel cell power generator comprising an electric deionization device for deionizing condensed water recovered from exhaust gas discharged from a fuel cell main body and / or reformer,
A water treatment device for a fuel cell power generator, wherein carbon dioxide recovery means is provided in a flow path on the concentrated water discharge side of the electric deionizer.   The water treatment apparatus for a fuel cell power generator according to claim 1, wherein a heating means is disposed between the electric deionization device and the carbon dioxide recovery means.   3. The fuel cell according to claim 1, wherein the carbon dioxide recovery unit includes a gas-liquid separator and a carbon dioxide recovery container that recovers the carbon dioxide separated by the gas-liquid separator. Water treatment equipment for power generation equipment.   The water treatment apparatus for a fuel cell power generator according to claim 3, wherein the volume of the carbon dioxide recovery container can vary depending on an internal pressure.

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