JP2009196866A - Reforming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a highly reliable reforming apparatus in which, even if water containing a component hard to be vaporized is used for reforming water, the component concentrated or accumulated from the reforming water does not clog a flow passage to thereby secure a prescribed flow rate, and prescribed output does not reduce. <P>SOLUTION: The reforming apparatus comprises: an evaporation section 26 heating reforming water to generate steam; a reforming section 21 where fuel for reforming is charged to the steam evaporated at the evaporation section 26 and reformed gas is generated; a carbon monoxide reduction section 23 where the reformed gas is introduced from the reforming section 21 and carbon monoxide in the reformed gas is reduced; and a cooling section 22 which is arranged between the reforming section 21 and the carbon monoxide reduction section 23, cools the reformed gas generated at the reforming section 21 and heats the steam generated at the evaporation section 26, the reforming water passing through the evaporation section 26 being heated at the cooling section 22 and being fed to the reforming section 21, wherein a storage section storing the component concentrated or accumulated from the reforming water is provided below the interface at which the reformed gas is evaporated. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a reformer.

  As a type of reforming water passage in a conventional fuel gas reforming device for a fuel cell, one shown in Patent Document 1 is known. The reformed water must first be evaporated in order to be mixed with the reforming fuel to reform the fuel. In order to achieve efficient evaporation and reduction in size and weight, it is necessary to increase the heat exchange efficiency. As shown in FIG. 1 of Patent Document 1, the reforming water passage is narrow. It has a double-pipe structure so that it can effectively exchange heat with the surroundings. Moreover, also about patent document 2, for the same reason, the site | part considered to evaporate in the channel | path of reforming water is a single tube.

Most of the reformed water used in the above system is water collected in the system, so-called self-supporting water, but water from several percent to several tens of percent is supplied from water. And the tap water is mixed with self-supporting water, and after processing such as ion exchange, it is supplied to the reformer by a water pump. However, a small amount of silica component (compound containing Si) existing in tap water in an ionic state has a weak ion adsorption power when passing through an ion exchange resin. The silica component is washed away by the ions and remains in the water, and is supplied to the reformer as it is. Since the silica component cannot be present in the water vapor, when the water boils and evaporates, it precipitates and remains in the water, is concentrated for a long time, and solidifies.
JP 2003-321206 A JP 2002-372395 A

  In the prior art, since the flow path is narrow at the site where the reforming water evaporates, concentrated or accumulated components such as silica components tend to block the flow path, increasing the pressure loss of the reforming fuel supply and obtaining a predetermined flow rate. In this case, the predetermined output may decrease. Also, when the tap water is supplied to the reformer as it is, the concentrated or accumulated components are deposited and concentrated. Moreover, tap water contains the component which is hard to evaporate. Components that are difficult to vaporize are supplied to the reformer and concentrated or accumulated in the reformer.

  The present invention has been made in view of the above points. Even when water containing a component that is difficult to vaporize is used as reformed water, the concentrated or accumulated component does not block the flow path, and a predetermined flow rate is secured, and a predetermined output is obtained. An object of the present invention is to provide a highly reliable reformer that does not decrease.

  In order to solve the above-described problem, the structural feature of the invention according to claim 1 is that an evaporating unit that heats the reformed water to generate water vapor, and the reforming fuel is added to the water vapor evaporated in the evaporating unit. A reforming unit that is supplied and supplied to generate reformed gas, a carbon monoxide reducing unit that introduces the reformed gas from the reforming unit to reduce carbon monoxide in the reformed gas, and the reforming And a cooling unit that is disposed between the carbon monoxide reduction unit and cools the reformed gas generated in the reforming unit and heats the water vapor generated in the evaporation unit. In the reforming apparatus in which the quality water is heated by the cooling unit and sent to the reforming unit through the evaporation unit, the reforming water has a reservoir for storing components concentrated or accumulated from the reforming water. It is provided below the interface to be evaporated.

  The structural feature of the invention according to claim 2 is that the reforming gas is supplied by supplying the reforming fuel to the evaporating section for heating the reforming water to generate steam and the steam evaporated in the evaporating section. A reforming unit that generates carbon, a carbon monoxide reducing unit that introduces the reformed gas from the reforming unit to reduce carbon monoxide in the reformed gas, and the reforming unit and the carbon monoxide reducing unit And a cooling unit that cools the reformed gas generated in the reforming unit and heats the steam generated in the evaporation unit, and the reformed water passes through the evaporation unit. In the reformer heated by the cooling unit and sent to the reforming unit, the reforming water is evaporated through a reservoir having a predetermined volume with respect to the silica component precipitated from the reforming water and solidified. This is provided below the interface.

  The structural feature of the invention according to claim 3 is that, in claim 1 or 2, the carbon monoxide reduction part is provided below the cooling part, and the carbon monoxide reduction part is provided between the cooling part and the carbon monoxide reduction part. A manifold is provided in which water vapor generated in the evaporation section is introduced and led out to the cooling section, and the reservoir section is provided below the manifold and in contact with the upper surface of the carbon monoxide reduction section.

  The structural feature of the invention according to claim 4 is that, in claim 1 or 2, the reservoir is provided at the lower end of the evaporation section.

  According to the first aspect of the present invention configured as described above, the reservoir for storing the component concentrated or accumulated from the reformed water is provided below the interface where the reformed water is evaporated. This makes it difficult to vaporize under conditions where water evaporates, and it is difficult to evaporate under conditions where water evaporates, such as seawater containing salt, calcium ions or magnesium ions, hard water, etc., which is concentrated as the water evaporates. 100% tap water, well water, etc. containing particulate components that are concentrated as water evaporates, such as silica, which is a component and is difficult to ionize, i.e., it is easy to attach and detach electrons. When tap water, seawater, well water, etc. containing components that accumulate as water evaporates, such as sand, is used as the reformed water, the components that are concentrated or accumulated from the reformed water evaporate the reformed water. Is stored in a reservoir provided below the interface. Therefore, the flow path is blocked by the concentrated or accumulated components, the pressure loss of the flow path increases, and a predetermined flow rate cannot be obtained, and the predetermined output does not decrease.

  In the invention according to claim 2 configured as described above, a reservoir portion having a predetermined volume for the silica component deposited and solidified from the reformed water is provided below the interface where the reformed water is evaporated. It is done. The silica component thus precipitated and solidified is precipitated in the modified water and accumulated in the reservoir. Here, the predetermined volume is assumed, for example, when 100% tap water is used for the required service life of the reformer, and the worst conditions such as the silica content and the amount of water used are considered. In addition, the volume of silica that is accumulated and estimated, including the safety factor, is a volume that is estimated and determined, so even during the service life, the accumulated silica solids block the flow path, increasing the pressure loss of the flow path. The predetermined flow rate is not obtained and the predetermined output does not decrease. In addition, since the reservoir portion protrudes downward from the bottom of the reforming water flow path, the silica solid content flows out, adversely affects downstream accessories, and does not degrade performance.

  In the invention according to claim 3 configured as described above, since the reservoir portion having a large area in which the reforming water is accumulated is provided in contact with the upper surface of the carbon monoxide reduction portion, the temperature control of the carbon monoxide reduction portion is performed. Can be appropriately performed with high heat exchange efficiency. That is, the temperature of the carbon monoxide reduction part is controlled by increasing or decreasing the S (steam) / C (carbon) ratio, but the temperature adjustment is reformed in a reservoir part having a large contact area with the carbon monoxide reduction part. Since the heat exchange efficiency is improved by using water and water vapor passing through the reservoir, the energy conversion efficiency of the reformer, that is, the power generation efficiency of the fuel cell system using the reformer is also improved. Furthermore, when silica is accumulated in the reservoir, the silica is highly hydrophilic and contains a lot of water even when the amount of water in the reservoir is reduced and the interface of water is below the solid content of silica. Therefore, the temperature control effect of the carbon monoxide reduction unit can be maintained and the function of the reforming apparatus is not deteriorated, as in the case where water is sufficiently accumulated.

  According to the invention according to claim 4 configured as described above, the reservoir portion of the component concentrated or accumulated from the reformed water, including the silica component precipitated from the reformed water and solidified at the lower end of the evaporation section. Therefore, the concentrated or accumulated component blocks the flow path of the evaporation section, the pressure loss of the flow path increases, and a predetermined flow rate cannot be obtained, and the predetermined output does not decrease.

  Hereinafter, embodiments of the reformer according to the present invention will be described. FIG. 1 is a diagram showing an outline of a fuel cell system provided with this reformer. The fuel cell system includes a fuel cell 10 and a reformer 20 that generates a reformed gas containing hydrogen gas necessary for the fuel cell 10.

  The fuel cell 10 includes a fuel electrode 11, an air electrode 12 that is an oxidant electrode, and an electrolyte 13 interposed between the electrodes 11 and 12, and supplies the reformed gas supplied to the fuel electrode 11 and the air electrode 12. Electric power is generated using air (cathode air), which is the oxidant gas.

  The reformer 20 steam reforms the reforming fuel and supplies the hydrogen-rich reformed gas to the fuel cell 10. The reformer 20 includes a reforming unit 21, a cooling unit 22, a carbon monoxide reducing unit 23, It comprises a carbon oxide selective oxidation reaction part (hereinafter referred to as CO selective oxidation part) 24, a combustion part 25, and an evaporation part 26. Examples of the reforming fuel include natural gas, gas fuel for reforming such as LPG, and liquid fuel for reforming such as kerosene, gasoline, and methanol. In this embodiment, natural gas will be described.

  The reforming unit 21 generates and derives a reformed gas by feeding a reformed fuel to the steam generated by heating the reformed water in the evaporation unit 26 and mixing the reformed fuel. It is. The reforming portion 21 is formed in a bottomed cylindrical shape, and includes an annular folded channel 21a extending along the axis in the annular cylindrical portion.

  The return channel 21 a of the reforming unit 21 is filled with a catalyst 21 b (for example, Ru or Ni-based catalyst), and a mixed gas of reforming fuel and water vapor introduced from the water vapor supply pipe 51 is present. Heated and introduced by the cooling unit 22, reacted and reformed by the catalyst 21b to generate hydrogen gas and carbon monoxide gas (so-called steam reforming reaction). At the same time, a so-called carbon monoxide shift reaction occurs in which carbon monoxide generated in the steam reforming reaction reacts with steam to transform into hydrogen gas and carbon dioxide. These generated gases (so-called reformed gas) are led to a cooling unit (heat exchange unit) 22. The steam reforming reaction is an endothermic reaction, the carbon monoxide shift reaction is an exothermic reaction, and the activation temperature range of the catalyst 21b of the reforming unit 21 is 400 ° C to 800 ° C. The reforming unit 21 is provided with a temperature sensor (not shown) that measures the temperature in the reforming unit 21, for example, the temperature in the vicinity of the wall between the reforming unit 21.

  The cooling unit 22 is disposed between the reforming unit 21 and the carbon monoxide reduction unit 23, and includes a reformed gas generated and derived by the reforming unit 21, a reforming fuel, and reformed water (steam). A heat exchanger (heat exchanging unit) that exchanges heat with a mixed gas, wherein the reformed gas having a high temperature is cooled by the mixed gas having a low temperature and led to the carbon monoxide reducing unit 23 and mixed. The gas is heated by the reformed gas and sent to the reforming unit 21.

  A manifold 92 is provided between the cooling unit 22 and the carbon monoxide reduction unit 23, in which water vapor generated by the evaporation unit 26 is introduced and led out to the cooling unit 22. And in contact with the upper surface of the carbon monoxide reduction portion 23. The reservoir 91 projects downward from the bottom of the manifold 92 that forms the flow path of the reformed water that has become steam. As shown in FIG. 2, the manifold 92 and the reservoir 91 are provided with a space in the central portion through which the reformed gas generated in the reformer 21 passes vertically to be led out to the carbon monoxide reduction unit 23. Yes. Further, it is formed in an annular shape around the penetrating space, the upper part of the annular space constitutes a manifold 92, and the lower part constitutes a reservoir 91 having a predetermined volume and is in contact with the carbon monoxide reducing part 23. . A water vapor supply pipe 51 connected to the evaporation unit 26 is connected to the manifold 92. Further, a reforming fuel supply pipe 41 connected to a fuel supply source (not shown) (for example, a city gas pipe) is connected to the manifold 92, and the fuel pump 42 and desulfurization are sequentially connected to the reforming fuel supply pipe 41 from the upstream. A reformer 46 and a reforming fuel valve 43 are provided. The reforming fuel valve 43 opens and closes the reforming fuel supply pipe 41, and the fuel pump 42 supplies reforming fuel and combustion fuel and adjusts the supply amount. The desulfurizer 46 removes odorous components (for example, sulfur compounds) in the fuel. The fuel that is supplied to the reforming unit 21 and reformed is called reforming fuel, and the fuel that is supplied to the combustion unit 25 and burned is called combustion fuel.

  Further, a combustion fuel supply pipe 44 connected to the combustion section 25 is connected between the desulfurizer 46 and the reforming fuel valve 43 of the reforming fuel supply pipe 41, and the combustion fuel supply pipe 44 is connected. Is connected to a combustion air supply pipe 64. A combustion fuel valve 45 is provided in the combustion fuel supply pipe 44. The combustion fuel valve 45 opens and closes the combustion fuel supply pipe 44. When the fuel pump 42 is driven and the reforming fuel valve 43 is closed and the combustion fuel valve 45 is opened, the combustion fuel is supplied to the combustion unit 25, and the fuel pump 42 is driven and the reforming fuel. When the valve 43 is opened and the combustion fuel valve 45 is closed, the reforming fuel is supplied to the reforming unit 21.

  The connecting portions of the reforming fuel supply pipe 41 and the steam supply pipe 51 to the manifold 92 are such that the lower ends of the openings where the supply pipes 41 and 51 open into the manifold 92 are the upper ends of the reservoir 91 (two-dot chain lines). ) Is connected to be located above. The predetermined volume of the reservoir 91 is, for example, assumed that 100% tap water is used as the reformed water for the service life required for the reformer, and the silica content of water, the amount used, etc. The volume determined by estimating the maximum amount of accumulated silica, taking into account the worst-case conditions, and including the safety factor.

  In the present embodiment, the reforming fuel supply pipe 41 and the water vapor supply pipe 51 are separately connected to the manifold 92 from two directions. The present invention is also applicable to a configuration in which the reforming fuel supply pipe and the steam supply pipe are connected upstream, and the reforming fuel and the steam are mixed and introduced into the manifold 92. Also in this case, the lower end of the opening portion where one connecting pipe connected to the manifold 92 in a state where the reforming fuel and the steam are mixed opens to the manifold 92 is a reservoir 91 in which a predetermined volume is set. It connects so that it may be located above an upper end.

  The carbon monoxide reduction unit 23 reduces carbon monoxide in the reformed gas that is cooled by the cooling unit 22 from the reforming unit 21 and supplied through the central space of the manifold 92 and the reservoir 91. . The carbon monoxide reduction unit 23 includes a folded channel 23a extending along the vertical direction. The return channel 23a is filled with a catalyst 23b (for example, a Cu—Zn-based catalyst). In the carbon monoxide reduction unit 23, so-called carbon monoxide shift in which carbon monoxide and water vapor contained in the reformed gas introduced from the cooling unit 22 react with the catalyst 23b to be converted into hydrogen gas and carbon dioxide gas. A reaction is occurring. This carbon monoxide shift reaction is an exothermic reaction. In the carbon monoxide reduction unit 23, a temperature sensor (not shown) that measures the temperature of the catalyst 23b of the carbon monoxide reduction unit 23 is provided.

  The CO selective oxidation unit 24 further reduces the carbon monoxide in the reformed gas supplied from the carbon monoxide reduction unit 23 and supplies it to the fuel cell 10. The CO selective oxidation unit 24 is formed in a cylindrical shape, and is provided so as to cover the outer peripheral wall of the evaporation unit 26. The CO selective oxidation unit 24 is filled with a catalyst 24a (for example, a Ru or Pt catalyst).

  A connection pipe 89 connected to the carbon monoxide reduction section 23 and a reformed gas supply pipe 71 connected to the fuel electrode 11 of the fuel cell 10 are respectively provided at the lower side wall surface and the upper side wall surface of the CO selective oxidation unit 24. It is connected. An oxidizing air supply pipe 61 is connected to the connecting pipe 89. For this reason, the reformed gas from the carbon monoxide reducing section 23 and the oxidizing air from the atmosphere are introduced into the CO selective oxidizing section 24. . The oxidizing air supply pipe 61 is provided with an oxidizing air pump 62 and an oxidizing air valve 63 in order from the upstream. The oxidizing air pump 62 supplies oxidizing air and adjusts the supply amount, and the oxidizing air valve 63 opens and closes the oxidizing air supply pipe 61.

  Therefore, carbon monoxide in the reformed gas introduced into the CO selective oxidation unit 24 reacts (oxidizes) with oxygen in the oxidizing air to become carbon dioxide. This reaction is an exothermic reaction and is promoted by the catalyst 24a. Thereby, the reformed gas is derived by further reducing the carbon monoxide concentration (10 ppm or less) by the oxidation reaction, and is supplied to the fuel electrode 11 of the fuel cell 10.

  The CO selective oxidation unit 24 is connected to the inlet of the fuel electrode 11 of the fuel cell 10 via a reformed gas supply pipe 71, and the combustion unit 25 is connected to the outlet of the fuel electrode 11 via an offgas supply pipe 72. Has been. The bypass pipe 73 bypasses the fuel cell 10 and directly connects the reformed gas supply pipe 71 and the offgas supply pipe 72. An anode gas valve 74 is provided in the reformed gas supply pipe 71 between the branch point of the bypass pipe 73 and the fuel cell 10. The off gas supply pipe 72 is provided with an anode off gas valve 75 between the junction with the bypass pipe 73 and the fuel cell 10. A bypass valve 76 is provided in the bypass pipe 73.

  From the start of the fuel cell system to the start of power generation, the anode gas valve 74 and the anode off-gas valve 75 are closed and bypassed to avoid supplying reformed gas with a high carbon monoxide concentration from the reformer 20 to the fuel cell 10. In order to supply the reformed gas from the reformer 20 to the fuel cell 10 during the power generation operation, the anode gas valve 74 and the anode offgas valve 75 are opened and the bypass valve 76 is closed.

  Further, a cathode air supply pipe 67 is connected to the inlet of the air electrode 12 of the fuel cell 10, and an exhaust pipe 82 is connected to the outlet of the air electrode 12. The cathode air supply pipe 67 is provided with a cathode air pump 68 and a cathode air valve 69 in order from the upstream. The cathode air pump 68 supplies cathode air and adjusts the supply amount. The cathode air valve 69 opens and closes the cathode air supply pipe 67.

  A combustion fuel pipe 64 is connected to the combustion fuel supply pipe 44 between the combustion section 25 and the combustion fuel valve 45, and a combustion air supply pipe 64 is connected to the combustion fuel supply pipe 44. At least one of the reformed gas supplied from the fuel and the anode off-gas from the fuel cell 10 is combusted by the combustion air supplied by the combustion air pump 65, and the reforming unit 21 is heated by the combustion gas. . The combustion unit 25 generates combustion gas for heating the reforming unit 21 and supplying heat necessary for the steam reforming reaction. The lower end of the reforming unit 21 has a space in the inner peripheral wall. Inserted.

  A combustion fuel supply pipe 44 connected to a fuel supply source (for example, a city gas pipe) is connected to the combustion section 25, and other than the off-gas supply pipe 72 whose one end is connected to the outlet of the fuel electrode 11. The ends are connected. Basically, when the fuel cell 10 is started, combustion fuel is supplied to the combustion unit 25, and when the temperature of the carbon monoxide reduction unit 23 is lower than a predetermined temperature during the startup of the fuel cell 10, CO selective oxidation is performed. When the reformed gas from the unit 24 is supplied to the combustion unit 25 without passing through the fuel cell 10 and the temperature of the carbon monoxide reduction unit 23 becomes equal to or higher than a predetermined temperature and the power generation of the fuel cell 10 is started, the fuel cell 10 The discharged anode off-gas (reformed gas containing hydrogen that is not used in the fuel electrode 11 and reforming fuel that is not reformed in the reforming unit) is supplied to the combustion unit 25.

  In addition, during the power generation operation, if the amount of combustion heat from the reformed gas or anode off gas is insufficient to heat the reforming section to a predetermined temperature, an amount of combustion fuel corresponding to the shortage of combustion heat is added. Supply and supplement. In this way, a system that supplements not only the anode off-gas but also the insufficient heat quantity with the combustion fuel in the combustion section 25 is called a reheating system. In addition to this reheating system, the fuel cell system supplies only the anode off-gas to the combustion unit 25 during power generation operation, and does not supply additional combustible gas such as combustion fuel as in the reheating system. There is a less system. The present invention is applicable not only to a rebirth system but also to a rebirthless system.

  Further, a combustion air supply pipe 64 is connected to the combustion unit 25, and combustion air for burning (oxidizing) a combustible gas such as a combustion fuel, anode off gas, and reformed gas is supplied from the atmosphere. It has become so. The combustion air supply pipe 64 is provided with a combustion air pump 65 and a combustion air valve 66 in order from the upstream. The combustion air valve 66 opens and closes the combustion air supply pipe 64.

  When the combustion unit 25 configured as described above is ignited, the supplied combustion fuel, reformed gas or anode off-gas is combusted by the combustion air to generate high-temperature combustion gas. The combustion gas flows through the combustion gas passage 27 and is exhausted as combustion exhaust gas through the exhaust pipe 81. Thus, the combustion gas heats the reforming unit 21 and the evaporation unit 26 in this order. The combustion gas flow path 27 is formed along the inner peripheral wall of the reforming part 21, is folded and formed between the outer peripheral wall of the reforming part 21 and the inner peripheral wall of the heat insulating part 28, and is folded back to the heat insulating part 28. It is a flow path formed between the outer peripheral wall of this and the inner peripheral wall of the evaporation part 26. FIG.

  The evaporation unit 26 boils (evaporates) the reformed water to generate water vapor, and supplies the water vapor to the reformer 21 via the cooling unit 22. The evaporation part 26 is formed in a cylindrical shape and forms the outer peripheral wall of the combustion gas flow path 27.

  A water supply pipe 52 connected to a reforming water tank (not shown) is connected to the lower portion of the evaporation unit 26. A reservoir 93 having a predetermined volume is provided below the water supply pipe 52 at the lower end of the evaporator 26 (FIG. 1B, FIG. 3). The predetermined volume referred to here is, for example, that 100% of tap water is used as the reforming water for the service life required for the reformer, for example, in the same manner as the predetermined volume for the reservoir 91 described above. It is assumed that the volume is determined by estimating the maximum amount of accumulated silica, taking into account the worst conditions such as the silica content and amount of water used, and including the safety factor. Here, the reservoir 93 is preferably provided below the lower end of the adjacent combustion gas flow path 27. Further, it is desirable that the reservoir 93 protrudes on the outer diameter side opposite to the combustion gas flow path 27.

  A steam supply pipe 51 is connected to the upper part of the evaporation unit 26. The reformed water introduced from the reformed water tank is heated by the heat from the combustion gas and the heat from the CO selective oxidation unit 24 in the course of flowing through the evaporation unit 26 to become water vapor and the water vapor supply pipe 51. And it is sent to the reforming unit 21 via the cooling unit 22. The water supply pipe 52 is provided with a reforming water pump 53 and a reforming water valve 54 in order from the upstream. The reforming water pump 53 supplies reforming water to the evaporation unit 26. The reforming water valve 54 is reforming water adjusting means for opening and closing the water supply pipe 52 and adjusting the amount of reforming water supply. The supply amount of the reforming water may be adjusted by the reforming water pump 53. The evaporator 26 is provided with a temperature sensor (not shown) that detects the temperature in the evaporator 26. The temperature sensor is preferably provided at the downstream portion (exit side) in the evaporation portion 26.

  Next, the operation of the above-described fuel cell system will be described. When the start-up operation is started, the control device (not shown) opens the combustion air valve 66 and drives the combustion air pump 65 to supply the combustion air to the combustion unit 25. Further, the control device energizes the ignition electrode of the combustion unit 25. Further, the combustion fuel valve 45 is opened to drive the fuel pump 42 to supply the combustion fuel to the combustion unit 25. As a result, the combustion fuel is burned in the combustion section 25, and the reforming section 21 and the evaporation section 26 are heated by the combustion gas. At this time, the reforming fuel valve 43, the reforming water valve 54, the oxidizing air valve 63, the anode gas valve 74, the bypass valve 76, and the anode off-gas valve 75 are closed.

First, the reforming water valve 54 is opened, and the reforming water pump 53 is driven to supply a predetermined amount of water to the evaporation section 26, and then the supply of water is temporarily stopped. Thereafter, when the temperature of the evaporating unit 26 becomes equal to or higher than a predetermined value (for example, 100 ° C.), it is determined that steam has been generated, the reforming water valve 54 is opened again, and the reforming water pump 53 is driven to evaporate the unit 26. Supply of water at a predetermined flow rate is started. Although 90% or more of the water introduced into the evaporation unit 26 is reused in the system, the remaining water is replenished from the water supply. And although the water supplied to an evaporation part is purified through an ion exchange resin, a silica component may remain.
The reformed water introduced into the evaporation unit 26 is supplied so that the upper end of the water surface is located below the connection part with the steam supply pipe 51 connected to the upper part of the evaporation unit 26, and the reformed water in the evaporation unit 26 is supplied. Water vapor is generated by evaporation at the interface. Since the silica component contained in the reformed water is not evaporated together with the water, it is deposited, remains in the reformed water of the evaporation section 26, solidifies and precipitates, and is stored in the reservoir section 93 as time passes.

The water vapor evaporated by the evaporation unit 26 is guided to the water vapor supply pipe 51 and introduced into the manifold 92 provided below the cooling unit 22 and above the reservoir 91. However, in reality, not only vaporized water vapor is introduced into the manifold 92. Since water or the like scattered by boiling is also introduced at the same time, the manifold 92 sometimes accumulates water. In that case, the manifold 92 has a function as an evaporating part, and water evaporates from the interface of the water accumulated in the manifold 92 and is led out to the cooling part. Here too, the silica component contained in the reformed water (which is ionized in the form of HSiO ₃ ⁻ or the like in water) precipitates because it is not evaporated together with water, and remains in the water to solidify and precipitate (the solid content is usually SiO 2. ₂ ) It accumulates in the reservoir 91 over time.

  Thereafter, the reforming fuel valve 43 is opened, the fuel pump 42 is driven, and the reforming fuel is supplied to the manifold 92. As a result, a mixed gas of reforming fuel and water vapor is supplied to the reforming unit 21, and the above-described water vapor reforming reaction and carbon monoxide shift reaction occur to generate reformed gas. Then, the high-temperature reformed gas derived from the reforming unit 21 is sequentially supplied to the carbon monoxide reducing unit 23, and the carbon monoxide reducing unit 23 is sequentially heated from the upstream side by the temperature of the supplied reformed gas. When the heated upstream portion reaches the activation temperature of the carbon monoxide reduction unit 23, the temperature rise due to heat generation of the catalytic reaction is also added. As a result, after activation, the carbon monoxide reduction unit 23 gradually expands the region above the predetermined temperature from upstream to downstream, and sets the carbon monoxide concentration in the reformed gas to a predetermined value in the catalyst region that exceeds the predetermined temperature. It is possible to reduce the concentration to less than that.

  And it is determined whether the temperature of the thermometer installed in the predetermined place in the catalyst of the carbon monoxide reduction part 23 is more than predetermined temperature. When the temperature is lower than the predetermined temperature, it is determined that the warm-up has not been completed, that is, the carbon monoxide concentration in the reformed gas is higher than the predetermined concentration. The reformed gas at this time passes through the carbon monoxide reducing unit 23, and then, in the CO selective oxidizing unit 24, the oxidizing air valve 63 which is opened and started to be driven simultaneously with the reforming fuel valve 43 being opened. The carbon monoxide is reduced and led out by the oxidizing air supplied to the CO selective oxidation unit 24 by the oxidation air pump 62 and directly through the bypass pipe 73 without passing through the fuel cell 10. It is supplied to and burned.

  When the temperature is equal to or higher than the predetermined temperature, the warm-up is completed, and it is determined that the carbon monoxide concentration in the reformed gas is equal to or lower than the predetermined concentration, and the anode gas valve 74 and the anode offgas valve 75 are opened, and the bypass valve 76 is closed and the CO selective oxidation unit 24 is connected to the inlet of the fuel electrode 11 of the fuel cell 10 and the outlet of the fuel electrode 11 is connected to the combustion unit 25 to supply reformed gas for the cathode. The air valve 69 is opened, and the cathode air pump 68 is driven to start power generation.

  After the operation is finished, when the fuel cell system is stopped, the driving of the fuel pump 42 and the supply of the reforming fuel are sequentially stopped, and the reforming fuel valve 43 is closed. Thereafter, the reforming water pump 53 is stopped and the reforming water valve 54 is closed. Further, after the oxidation air pump 62 is stopped, the oxidation air valve 63 is closed, and then the fuel pump 42 is stopped and the combustion fuel valve 45 is closed. Finally, the combustion air pump 65 and the cathode air pump 68 are stopped, and then the combustion air valve 66, the anode gas valve 74, the anode off-gas valve 75, the bypass valve 76, and the cathode air valve 69 are sequentially closed. Thereby, the power generation of the fuel cell 10 is stopped, and this program is terminated.

  As is clear from the above description, in this embodiment, since the reservoir portion 91 having a predetermined volume is provided at the lower portion of the manifold 92, the reformed water of 100% tap water is used. Even when the quality device is used for the service life in the worst condition, the lower end of the opening portion where the connected reforming fuel supply pipe 41 and the steam supply pipe 51 are connected to the manifold 92 and opened is the upper end of the reservoir 91 ( Since the accumulated silica solid content does not block the flow paths of the reforming fuel supply pipe 41 and the water vapor supply pipe 51, the pressure loss of the flow path increases and a predetermined flow rate is set. Is not obtained, and the predetermined output does not decrease.

  Further, since the reservoir 91 is provided below the manifold 92, silica solids flow out, adversely affect downstream accessories, and performance does not deteriorate.

  Furthermore, when the temperature control of the carbon monoxide reduction unit 23 is performed, the control is adjusted by increasing / decreasing the S / C ratio, which is the ratio of the water vapor molecular weight and the carbon molecular weight. It is made of water or water vapor accumulated near the lower carbon monoxide reduction portion 23. Since the manifold portion 92 having the reservoir portion 91 disposed below is provided below the cooling portion and on the upper surface of the carbon monoxide reduction portion 23, a water reservoir portion having a wide area is secured, thereby Since the efficiency of heat exchange with the carbon reduction unit 23 is improved, it is easy to adjust the increase / decrease in the S / C ratio, and thus the temperature control of the carbon monoxide reduction unit 23 is facilitated. In addition, by improving the heat exchange efficiency, the energy conversion efficiency of the reformer is improved, and consequently the power generation efficiency of the system is improved.

  Even if the amount of the reforming water in the reservoir 91 is reduced and the interface of the reforming water is lower than the solidified silica, the silica itself has high hydrophilicity and water retention, so that the silica contains water. The water thus evaporated can be responsible for adjusting the temperature control by increasing or decreasing the S / C ratio, and the function of the reformer is not impaired.

  In the present embodiment, the reservoir 93 having a predetermined volume is provided at the lower end of the evaporator 26, so that when the reformed water is evaporated in the evaporator, the silica component contained in the water is mixed with the water. Since it does not evaporate, it precipitates, remains in water, solidifies and precipitates, and accumulates in the reservoir 93 and solidifies with time. However, since the lower end of the opening where the reforming water supply pipe 52 is connected to the evaporation section 26 is opened above the upper end (two-dot chain line) 94 of the reservoir section 93, 100% tap water reforming water is used. Even when the reformer is used for the service life under the worst conditions, the accumulated silica component does not block the reformed water supply pipe 52 and the flow path of the evaporation section 26. Accordingly, the pressure loss of the flow path increases and a predetermined flow rate cannot be obtained, so that the predetermined output does not decrease. Further, since the reservoir portion 93 is provided at the lower end portion of the evaporation portion 26, the silica solid content flows out, adversely affects downstream auxiliary machines, and does not cause performance deterioration.

  In the above-described embodiment, the reformed water is mainly used as the self-supporting water, and when it is insufficient, the tap water is replenished. However, the water used as the reformed water is not limited to a mixture of self-sustained water and tap water, but is difficult to vaporize under conditions where water evaporates, and is concentrated as the water evaporates, for example, salt content Water such as silica, which is a component that is difficult to vaporize under conditions where water evaporates, such as seawater and hard water containing calcium ions or magnesium ions, and that is difficult to ionize, that is, electrons are easy to detach and deposit. Tap water, seawater, well water, etc., containing components that accumulate as the water evaporates, such as tap water, well water, etc., which contains components that are concentrated as the water evaporates. .

  Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the gist of the present invention described in the claims. Of course.

1 is a schematic diagram showing an outline of an embodiment of a fuel cell system according to the present invention. The expanded sectional view of the reservoir part 91 of the FIG. 1A part which concerns on this embodiment. The expanded sectional view of the pool part 93 of the FIG. 1B part which concerns on this embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Fuel cell, 20 ... Reformer, 21 ... Reforming part, 22 ... Cooling part, 23 ... Carbon monoxide reduction part, 24 ... Carbon monoxide selective oxidation reaction part (CO selective oxidation part), 25 ... Combustion part , 26 ... evaporation section, 27 ... combustion gas flow path, 41 ... reforming fuel supply pipe, 42 ... fuel pump, 51 ... steam supply pipe, 52 ... water supply pipe, 53 ... reforming water pump, 54 ... reforming water Valve 91, reservoir, 92 manifold, 93 reservoir 94, upper end of reservoir 93

Claims (4)

An evaporator that heats the reformed water to produce water vapor;
A reforming unit for supplying reforming fuel to the water vapor evaporated in the evaporation unit to generate reformed gas;
A carbon monoxide reduction unit that introduces the reformed gas from the reforming unit and reduces carbon monoxide in the reformed gas; and
A cooling unit that is disposed between the reforming unit and the carbon monoxide reduction unit, cools the reformed gas generated in the reforming unit, and heats the steam generated in the evaporation unit. In the reformer in which the reforming water is heated in the cooling unit and sent to the reforming unit through the evaporation unit,
A reformer comprising a reservoir for storing components concentrated or accumulated from the reformed water, below the interface where the reformed water is evaporated. An evaporator that heats the reformed water to produce water vapor;
A reforming unit for supplying reforming fuel to the water vapor evaporated in the evaporation unit to generate reformed gas;
A carbon monoxide reduction unit that introduces the reformed gas from the reforming unit and reduces carbon monoxide in the reformed gas; and
A cooling unit that is disposed between the reforming unit and the carbon monoxide reduction unit, cools the reformed gas generated in the reforming unit, and heats the steam generated in the evaporation unit. In the reformer in which the reformed water is heated by the cooling unit and sent to the reforming unit through the evaporation unit,
A reforming apparatus comprising a reservoir having a predetermined volume for a silica component deposited and solidified from the reformed water, below an interface where the reformed water is evaporated.   3. The cooling unit according to claim 1, wherein the carbon monoxide reduction unit is provided below the cooling unit, and water vapor generated in the evaporation unit is introduced between the carbon monoxide reduction unit and the cooling unit. The reformer is characterized in that a manifold led out is provided, and the reservoir is provided below the manifold and in contact with the upper surface of the carbon monoxide reduction unit. The reformer according to claim 1, wherein the reservoir is provided at a lower end of the evaporation unit.

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