JP2007325988A - Decarboxylation device, and fuel cell power generation device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a decarboxylation device capable of efficiently removing carbon dioxide from water to be treated, which contains carbon dioxide such as flocculated water, and to provide a fuel cell power generation device using decarboxylation device. <P>SOLUTION: This decarboxylation device 11 is provided with a storing part 100 for storing the water tro be treated, and a bubbling mechanism 110 for blowing air into the water 120 to be treated stored in the storing part 100. The bubbling mechanism 110 has an air introducing port 111, a jetting port 112 blowing air into the treating object water 120, an exhaust port 113 exhausting air taken into the bubbling mechanism 110 to a gas phase outside the bubbling mechanism 110, and a pressure regulation mechanism disposed in the exhaust port 113 for regulating the pressure in the bubbling mechanism 110. The decarboxylation device 11 is disposed in the fuel cell power generation device. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a decarboxylation device for removing carbon dioxide from water to be treated containing carbon dioxide such as condensed water, and a fuel cell power generation device including the same.

  A fuel cell power generation device is a power generation device that directly converts the binding energy of hydrogen and oxygen into electrical energy. In such a fuel cell power generation device, a fuel cell main body configured by laminating a plurality of unit cells including an electrolyte, a fuel electrode and an air electrode sandwiching the electrolyte is used, and a hydrocarbon system such as natural gas is used. Hydrogen in the fuel gas obtained by steam reforming the raw fuel and oxygen in the air are supplied to the fuel electrode and air electrode of the fuel cell, respectively, and are generated using the electrochemical reaction that occurs between the two electrodes. Getting power.

  In order to reform raw fuel into fuel gas, a reformer is generally used in which steam is added to a hydrocarbon-based raw fuel such as natural gas and the reaction between water and the raw fuel is promoted by a catalyst. Therefore, it is necessary to replenish the reformer with water necessary for reforming the fuel.

  In general, the water used for the reforming reaction is an ion exchange type water treatment device that uses condensed water obtained by condensing exhaust gas such as combustion exhaust gas discharged from the reformer and reaction exhaust gas discharged from the fuel cell body. For example, ion-exchanged water obtained by removing impurities is used.

  However, since the flue gas discharged from the reformer has a relatively high carbon dioxide concentration, carbon dioxide is dissolved to a substantially saturated amount in the condensed water that can be recovered from the flue gas. For this reason, in order to reduce the load on the water treatment apparatus, these condensed waters are decarboxylated before the purification treatment to remove carbon dioxide dissolved in the condensed water.

  As a decarboxylation method of condensed water, a method using a diffusion phenomenon is generally performed in which condensed water and air are brought into contact with each other to diffuse carbon dioxide in the condensed water to the air side by a diffusion phenomenon. ing.

  As such a decarbonation apparatus utilizing the diffusion phenomenon, a pipe filled with a filler such as a Raschig ring has been conventionally used, and supplies condensed water to the upper part of the pipe and removes it from the lower part of the pipe. Carbonation air is supplied, and decarbonation treatment is performed by bringing the condensed water into contact with decarbonation air while gravity dropping.

Patent Documents 1 and 2 below disclose a method of decarboxylation by blowing decarbonation air into condensed water and bubbling the condensed water.
JP-A-11-97046 JP 2005-32673 A

  The bubbling type decarboxylation treatment method has the following problems, although a high effect is obtained as compared with the decarboxylation treatment method using the diffusion phenomenon.

  That is, exhaust air discharged from the air electrode of the fuel cell main body is almost the same as normal air, and thus is used as decarbonation air, but is discharged depending on the operating state of the fuel cell main body. The amount of exhaust air also fluctuates. For this reason, the decarboxylation efficiency by bubbling is likely to vary depending on the operating state of the fuel cell body, and it has been difficult to obtain a stable effect.

  On the other hand, it is conceivable to adjust the hole diameter and the number of holes in the air outlet of the bubbling mechanism so that the amount of air discharged at the minimum load of the fuel cell body is sufficient to obtain sufficient decarbonation performance. As the load on the battery body increased, the momentum of bubbling increased and there were problems such as noise. Further, the pressure loss increases as the load increases, and the load applied to the air supply device that supplies air to the air electrode increases as the load of the fuel cell main body increases. For this reason, an air supply device having a high processing capacity is required, which necessitates device costs and operation costs, and further, it has been difficult to reduce the size of the fuel cell power generation device.

  Accordingly, an object of the present invention is to solve the above problems and provide a decarboxylation device that can efficiently remove carbon dioxide from water to be treated containing carbon dioxide such as condensed water, and a fuel cell power generator using the same. It is in.

  In order to achieve the above object, a decarboxylation apparatus of the present invention is a decarboxylation apparatus including a storage unit that stores water to be treated and a bubbling mechanism that blows air into the water to be treated stored in the storage unit. The bubbling mechanism includes an air introduction port, a jet port for blowing air into the water to be treated, and an exhaust port for exhausting the air taken into the bubbling mechanism to a gas phase outside the bubbling mechanism. And a pressure adjusting mechanism for adjusting the pressure in the bubbling mechanism disposed in the exhaust port.

  According to the decarboxylation device of the present invention, for example, when the bubbling amount is adjusted so that the decarboxylation efficiency can be sufficiently obtained with the minimum air supply amount, and the air supply amount increases due to the fluctuation of the air supply amount. In this case, it is possible to suppress an increase in pressure in the bubbling mechanism by exhausting excess air to the external gas phase through the exhaust port by the pressure adjusting mechanism. For this reason, the load concerning the air supply apparatus etc. for supplying air to a bubbling mechanism can be reduced, and the operating cost, apparatus cost, and apparatus space of the whole apparatus can be reduced. In addition, almost stable bubbling efficiency can be obtained regardless of the amount of air supplied to the bubbling mechanism, and a stable decarboxylation state can be maintained without causing problems such as noise due to excessive bubbling.

  Moreover, the decarbonation apparatus of this invention WHEREIN: It is preferable that the said pressure adjustment mechanism is an elastic board which has a slit-shaped opening part. According to this aspect, when there is little air quantity to a bubbling mechanism, a slit part closes and the pressure fall in a bubbling mechanism can be prevented. On the other hand, when the amount of air to the bubbling mechanism is large, the slit portion is lifted upward and the amount of exhaust increases, so that the pressure in the bubbling mechanism can be kept constant without being affected by fluctuations in the amount of air supply.

  In the decarboxylation apparatus of the present invention, it is preferable that the pressure adjusting mechanism is a lid biased in a closing direction by a spring or a weight. According to this aspect, since the opening degree of the lid disposed at the exhaust port varies according to the amount of air to the bubbling mechanism, the pressure in the bubbling mechanism can be kept constant regardless of the amount of air supply. .

  On the other hand, the fuel cell power generator according to the present invention includes a fuel cell body in which a plurality of unit cells each having an electrolyte sandwiched between a fuel electrode and an air electrode are stacked, and reforms the fuel and supplies the reformed gas to the fuel electrode. A reformer, an air supply device for supplying air to the air electrode, a condensation heat exchanger for recovering condensed water from exhaust gas discharged from the fuel cell body and / or the reformer, and the condensed water In the fuel cell power generation device including a decarbonation device that removes dissolved carbon dioxide gas and a water tank that stores condensed water decarboxylated by the decarbonation device, the decarbonation device includes the condensed water. And a bubbling mechanism for blowing decarbonation air into the condensed water stored in the storage part, wherein the bubbling mechanism includes a decarbonating air inlet and the condensed water. Inject decarboxylation air into A jet port, an exhaust port for exhausting the decarbonation air taken into the bubbling mechanism to a gas phase outside the bubbling mechanism, and a pressure for adjusting the pressure in the bubbling mechanism disposed at the exhaust port It has an adjustment mechanism.

  According to the fuel cell power generator, for example, when the bubbling amount is adjusted so that the decarboxylation efficiency is sufficiently obtained with the minimum air supply amount, and the air supply amount increases due to the fluctuation of the air supply amount, The excess pressure in the bubbling mechanism can be suppressed by exhausting excess air to the external gas phase through the exhaust port by the pressure adjusting mechanism. For this reason, the load concerning the air supply apparatus etc. for supplying air to a bubbling mechanism can be reduced, and the operating cost, apparatus cost, and apparatus space of the whole apparatus can be reduced. In addition, almost stable bubbling efficiency can be obtained regardless of the amount of air supplied to the bubbling mechanism, and a stable decarboxylation state can be maintained without causing problems such as noise due to excessive bubbling.

  In the fuel cell power generator of the present invention, it is preferable that the decarbonation air is exhaust air discharged from the air electrode side of the fuel cell main body. Since the exhaust air has a low carbon dioxide concentration and is almost the same as normal air, the exhaust gas can be used effectively.

  In the fuel cell power generator of the present invention, it is preferable that the pressure adjustment mechanism is an elastic plate having a slit-shaped opening. According to this aspect, when the supply amount of decarbonation air is small, the slit portion is elastically closed, and a pressure drop in the bubbling mechanism can be prevented. On the other hand, when the supply amount of decarbonation air is large, the slit portion opens against the elastic force and the exhaust amount increases. For this reason, the pressure in the bubbling mechanism can be kept constant without being affected by fluctuations in the supply amount of decarbonation air.

  In the fuel cell power generator of the present invention, it is preferable that the pressure adjusting mechanism is a lid biased in a closing direction by a spring or a weight. According to this aspect, since the opening degree of the lid disposed at the exhaust port varies depending on the supply amount of decarbonation air, the pressure in the bubbling mechanism is not dependent on the supply amount of decarbonation air. Can be kept constant.

  According to the present invention, for example, even when the bubbling amount is adjusted so that the decarboxylation efficiency can be sufficiently obtained with the minimum air supply amount, the pressure fluctuation in the bubbling mechanism hardly occurs due to the fluctuation of the air supply amount. The load applied to the air supply device for supplying air to the bubbling mechanism can be reduced, and a stable decarboxylation state can be maintained without causing problems such as noise.

  Hereinafter, embodiments of a fuel cell power generator according to the present invention will be described with reference to the drawings. FIG. 1 shows a schematic configuration diagram of a fuel cell power generator of the present invention, and FIG. 2 shows a schematic configuration diagram of a first embodiment of a decarboxylation device of the present invention.

  In addition, the decarboxylation apparatus of this invention shown below can be used also for uses other than a fuel cell power generation apparatus. That is, if the water to be treated is water in which carbon dioxide is dissolved, decarboxylation treatment can be preferably performed, not limited to the condensed water recovered from the combustion exhaust gas of the fuel cell power generator.

  The fuel cell power generator according to the present invention includes a fuel electrode 1a and an air electrode 1b that sandwich an electrolyte 1c, and a cooling system 1d having a cooling pipe that is disposed each time a plurality of unit cells made of these are stacked. A fuel cell body 1, a reformer 3 for supplying a reformed gas mainly composed of hydrogen obtained by reforming the fuel to the fuel electrode 1a, and an air supply device 7 for supplying air to the air electrode 1b. , A condensation heat exchanger 22 for recovering condensed water from the exhaust gas discharged from the fuel cell main body 1 and / or the reformer 3, and a decarbonation apparatus of the present invention for removing carbon dioxide dissolved in the recovered condensed water 11 and a water tank 10 for storing condensed water decarboxylated by the decarbonator 11.

  The reformer 3 includes a reforming catalyst unit 3a and a burner unit 3b. The reforming raw material input side of the reforming catalyst unit 3a is connected to the desulfurizer 2 via a raw material supply line L3. The raw material supply line L3 is branched and connected to the purified water storage tank 9 via the purified water supply line L4. The reformed gas recovery side is connected to the fuel electrode 1a via a reformed gas supply line L1 in which the reformer 4 and the CO remover 5 are arranged. On the other hand, the fuel inlet 3c of the burner section 3b is connected to the starting fuel supply line L5 branched from the raw material supply line L3, the combustion air supply line L6 connected to the combustion air blower 6, and the off-gas discharge side of the fuel electrode 1a. The off-gas supply line L7 in which the fuel preheater 21 to be disposed is connected. Further, the combustion exhaust gas discharge port 3d of the burner portion 3b is connected to the condensation heat exchanger 22 via a combustion exhaust gas line L8 where the fuel preheater 21 is disposed.

  In the reformer 3, the combustion air supplied from the combustion air supply line L6 and the off-gas supplied from the raw fuel and / or off-gas supply line L7 supplied from the starting fuel supply line L5 in the burner unit 3b. And the reforming catalyst unit 3a is heated, and the reforming catalyst unit 3a supplies the raw fuel desulfurized by the desulfurizer 2 supplied from the raw material supply line L3 and the purified water supply line L4. The reformed water is subjected to a reforming reaction to produce a reformed gas rich in hydrogen. The reformed gas generated by the reformer 3 is supplied from the reformed gas supply line L1 to the fuel electrode 1a after the carbon monoxide concentration is reduced by the reformer 4 and the CO remover 5. .

  The exhaust air gas discharge side of the air electrode 1b of the fuel cell main body 1 is connected to the condensation heat exchanger 22 via the air discharge line L9.

  The upper side of the condensation heat exchanger 22 is connected to the combustion exhaust gas line L8 and the air discharge line L9. Further, the lower side of the condensation heat exchanger 22 includes a decarbonation air supply line L11 for supplying exhaust air gas and condensed water that have been condensed by the condensation heat exchanger 22 to the decarboxylation device 11, and combustion after the condensation treatment. A condensed water recovery line L10 for supplying exhaust gas and condensed water to the decarbonation device 11 is connected.

  The decarbonation device 11 is mainly configured by a storage unit 100 that temporarily stores condensed water 120 and a bubbling mechanism 110 that blows decarbonation air into the condensed water 120 stored in the storage unit 100.

  In this embodiment, the decarboxylation device 11 shown in FIG. 2 is used. That is, in the upper part of the decarbonation device 11, a drain port 102 that is an introduction part of condensed water connected to the condensed water recovery line L10, and an exhaust gas that discharges decarbonation air and combustion exhaust gas that have taken in carbon dioxide in the condensed water. The mouth 101 is arranged. In addition, on the lower side, a blowing port 103 which is a decarboxylation air introduction portion connected to the decarboxylation air supply line L11 is disposed. Further, the inside is a condensate water storage unit 100, and an overflow pipe 104 extending in a predetermined height direction and a bubbling mechanism 110 for blowing air to the condensate water 120 stored in the storage unit 100 are arranged. .

  The bubbling mechanism 110 has a cylindrical case as a whole, and includes an air introduction port 111 connected to the blowing port 103, a jet port 112 that blows air into the condensed water 120, and decarboxylation air taken into the bubbling mechanism 110. The exhaust port 113 exhausts the gas to the gas phase outside the bubbling mechanism 110 and the lid 114a urged in a direction to close the exhaust port 113 by the weight 114c. The lid 114a is openable and closable with the exhaust port 113 and one end fixed by a hinge 114b.

  Condensed water to be decarboxylated is supplied from the drain port 102 and temporarily stored in the storage unit 100. Then, decarbonation air is supplied into the bubbling mechanism 110, and bubbling treatment is performed by blowing decarbonation air onto the condensed water 120 stored in the storage unit 100 from the ejection port 112, and dissolved in the condensed water 120. Degas carbon dioxide. The air that has taken in the carbon dioxide in the condensed water 120 is exhausted from the exhaust port 101 to the outside of the system.

  Here, in the conventional bubbling mechanism, when decarbonation air exceeding the amount required for the bubbling process is supplied to the bubbling mechanism 110 depending on the operating state of the fuel cell body, the pressure in the bubbling mechanism 110 increases, Loss increases and it becomes difficult to supply decarbonation air to the bubbling mechanism 110. Further, since bubbling is performed vigorously, problems such as noise occur.

  In the present invention, the bubbling mechanism 110 is provided with an exhaust port 113 for exhausting excessively decarboxylated air to the outside air. Further, the exhaust port 113 is urged in a closing direction by a weight 114c and can be opened and closed. By installing the lid 114a disposed in the lid 114a, the lid 114a opens according to the pressure in the bubbling mechanism 110, and the degree of opening increases as the pressure increases. For this reason, the air in the bubbling mechanism 110 can be exhausted with an exhaust amount corresponding to the pressure in the bubbling mechanism 110, whereby the pressure in the bubbling mechanism 110 can be maintained in a substantially constant state.

  Therefore, for example, even when the air supply amount increases due to the operating state of the fuel cell main body 1 or the like, the pressure loss for passing through the bubbling mechanism 110 is unlikely to increase, and the load on the air supply device 7 can be reduced. . Further, since the amount of bubbling air does not become excessive, problems such as noise do not occur.

  The condensed water decarboxylated by the decarboxylation device 11 is introduced into the water tank 10 and supplied from the decarboxylated condensed water recovery line L12 to the water treatment device 12. The condensed water (purified water) purified by the water treatment device 12 is supplied to the purified water storage tank 9 and supplied from the cooling water line L13 to the cooling system 1d of the fuel cell main body 1 and the condensation heat exchanger 22. The cooling water can be recycled and supplied to the reforming catalyst unit 3a of the reformer 3 from the purified water supply line L4 and used for the reforming reaction of the raw fuel.

  As described above, according to the fuel cell power generator of the present invention, the decarbonation treatment of the condensed water can be performed almost stably even if the supply amount of the decarboxylation air varies, and the decarbonation air is further reduced. Since the pressure loss for passing through the bubbling mechanism 110 can be reduced, the operating cost, the device cost, etc. can be reduced.

  FIG. 3 shows a second embodiment of the decarboxylation device 11 used in the fuel cell power generator of the present invention.

  The difference from the decarbonation device 11 of the first embodiment is that a preliminary deaeration unit 130 filled with a lash ring 135 such as SUS is disposed above the decarbonation device 11.

  According to this aspect, the condensed water supplied to the decarboxylation device 11 from the drain port 102 can be subjected to the preliminary deaeration treatment by the preliminary deaeration unit 130, so that the decarbonation efficiency of the condensed water is improved.

  FIG. 4 shows a third embodiment of the decarboxylation device 11 used in the fuel cell power generator of the present invention.

  The difference from the decarbonation device 11 of the first embodiment is that an elastic plate 115 a having a slit-like opening (slit part) 115 b is arranged at the exhaust port 113.

  Examples of the elastic plate 115a include fluorine rubber, nitrile rubber (NBR), and the like.

  According to this aspect, when the air supply amount to the bubbling mechanism 110 is small, that is, when the pressure in the bubbling mechanism 110 is low, the slit portion 115b is elastically closed, and the pressure drop of the bubbling mechanism 110 can be prevented. On the other hand, when the air supply amount to the bubbling mechanism 110 is large, the slit portion 115b is lifted upward and opens against the elastic force, and the degree of opening increases as the pressure increases. It can be exhausted. For this reason, the pressure in the bubbling mechanism 110 can be maintained substantially constant without being affected by fluctuations in the air supply amount.

  FIG. 5 shows a fourth embodiment of the decarboxylation device 11 used in the fuel cell power generator of the present invention.

  The difference from the decarboxylation device 11 of the first embodiment is that a lid 116a urged in a closing direction by a spring 116b is disposed at the exhaust port 113.

  According to this aspect, the extension of the spring 116b varies depending on the amount of air supplied to the bubbling mechanism 110, that is, the pressure in the bubbling mechanism 110, and the opening degree of the lid 116a varies. The pressure in the bubbling mechanism 110 can be maintained almost constant without being affected by the above.

It is a schematic block diagram of the fuel cell power generator of the present invention. It is a schematic block diagram which shows 1st Embodiment of the decarboxylation apparatus of this invention. It is a schematic block diagram which shows 2nd Embodiment of the decarboxylation apparatus of this invention. It is a schematic block diagram which shows 3rd Embodiment of the decarboxylation apparatus of this invention. It is a schematic block diagram which shows 4th Embodiment of the decarboxylation apparatus of this invention.

Explanation of symbols

1: fuel cell body 2: desulfurizer 3: reformer 4: reformer 5: CO remover 7: air supply device 9: purified water storage tank 10: water tank 11: decarbonation device 12: water treatment device 21: Fuel preheater 22: Condensation heat exchanger 100: Reservoir 101: Exhaust port 102: Drain port 103: Blow port 104: Overflow pipe 110: Bubbling mechanism 111: Air inlet 112: Jet port 113: Exhaust port 114b: Hinge 114a 116a: lid 114c: weight 115b: slit 115a: elastic plate 116b: spring 120: condensed water 130: preliminary deaeration unit

Claims (7)

A decarboxylation device comprising a storage section for storing treated water and a bubbling mechanism for blowing air into the treated water stored in the storage section,
The bubbling mechanism includes an air introduction port, a jet port for blowing air into the water to be treated, an exhaust port for exhausting the air taken into the bubbling mechanism to a gas phase outside the bubbling mechanism, And a pressure adjusting mechanism for adjusting a pressure in the bubbling mechanism disposed in the mouth.   The decarbonation apparatus according to claim 1, wherein the pressure adjustment mechanism is an elastic plate having a slit-shaped opening.   The decarbonation apparatus according to claim 1, wherein the pressure adjustment mechanism is a lid biased in a closing direction by a spring or a weight. A fuel cell main body in which a plurality of unit cells each having an electrolyte sandwiched between a fuel electrode and an air electrode are stacked, a reformer that reforms fuel and supplies reformed gas to the fuel electrode, and air to the air electrode An air supply device to supply, a condensation heat exchanger for recovering condensed water from exhaust gas discharged from the fuel cell main body and / or the reformer, and decarbonation for removing carbon dioxide dissolved in the condensed water In a fuel cell power generator comprising a device and a water tank for storing condensed water decarboxylated by the decarboxylation device,
The decarboxylation device includes a storage unit that temporarily stores the condensed water, and a bubbling mechanism that blows decarbonation air into the condensed water stored in the storage unit.
The bubbling mechanism includes an introduction port for decarbonation air, a jet port for blowing decarbonation air into the condensed water, and the decarbonation air taken into the bubbling mechanism to a gas phase outside the bubbling mechanism. A fuel cell power generator comprising an exhaust port for exhausting and a pressure adjusting mechanism for adjusting a pressure in the bubbling mechanism disposed in the exhaust port.   The fuel cell power generator according to claim 4, wherein the decarbonation air is exhaust air discharged from an air electrode side of the fuel cell main body.   The fuel cell power generator according to claim 4 or 5, wherein the pressure adjusting mechanism is an elastic plate having a slit-like opening.   The fuel cell power generator according to claim 4 or 5, wherein the pressure adjusting mechanism is a lid biased in a closing direction by a spring or a weight.

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