JP2009104832A - Gas-liquid separator and fuel cell system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a gas-liquid separator not disturbing exhaust of separated liquid and to provide a fuel cell system suitable for using the gas-liquid separator. <P>SOLUTION: The gas-liquid separator 10 is equipped with a container 11 introducing mixed fluid Fm containing steam, condensing and separating steam and storing in the lower part; a drain mechanism 12 exhausting recovered water w from the container 11 when the recovered water w stored in the lower part of the container 11 is raised than the prescribed liquid level; and a heating means 15 giving a heating value sterilizing bacteria becoming cause disturbing exhaust of the recovered water w from the container 11 to the recovered water w stored in the lower part of the container 11. The gas-liquid separator 10 is mounted on at least one of a reformed gas line, an anode offgas line, a cathode offgas line, and an exhaust gas line in the fuel cell system. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a gas-liquid separator and a fuel cell system, and more particularly to a gas-liquid separator that does not hinder the discharge of separated liquid, and a fuel cell system suitable for use of the gas-liquid separator.

Water generated by power generation in the fuel cell contained in the fuel exhaust gas discharged from the fuel cell is reused as a fuel exhaust gas in the gas-liquid separator to be reused as a raw material for the hydrogen generation reaction in the fuel processing device (reformer). Often separated from the inside. The separated water used for reuse generally has a low residual chlorine concentration and has a water quality that facilitates the growth of fungi. Fungi that have entered the fuel cell power generation system can be found in the fuel processor (reformer). Proliferation of methanol produced as a side reaction as a nutrient source may cause clogging of water piping in the fuel cell power generation system. Gas-liquid separation that separates the fuel exhaust gas discharged from the fuel cell into gas and liquid as a system to recover the recovered water from the fuel exhaust gas in the absence of fungal nutrients in order to avoid causing water pipe clogging The separated liquid provided on the circulating water recovery path downstream of the gas-liquid separator and the circulating water recovery path for collecting the separated liquid as circulating water and sending it to the water storage tank There is a fuel cell power generation system provided with a heating device (see, for example, Patent Document 1).
JP 2004-311180 A

  However, in the above fuel cell power generation system, when fungi grow in the gas-liquid separator, discharge of recovered water from the gas-liquid separator may be inhibited.

  An object of the present invention is to provide a gas-liquid separator capable of preventing the discharge of the separated liquid from being inhibited, and a fuel cell system suitable for use of the gas-liquid separator. To do.

  In order to achieve the above object, the gas-liquid separator according to the first aspect of the present invention introduces a gas Fm containing water vapor, for example, as shown in FIG. The recovered water w stored in the lower portion of the container 11 and condensed and separated from the water vapor rises above a predetermined liquid level PL (see, for example, FIG. 2). A drain mechanism 12 for discharging; and heating means 15 for giving heat to the recovered water w stored in the lower part of the container 11 with a heat quantity for sterilizing fungi that inhibits the discharge of the recovered water w from the container 11.

  If comprised in this way, since it has a heating means to give the amount of heat which sterilizes the fungi which becomes the cause which inhibits discharge of recovery water from a container to recovery water stored at the lower part of a container, it is stored in the lower part of a container. Fungi can be prevented from being generated in the recovered water, and even if it is generated, it can be sterilized and the discharge of recovered water from the container can be prevented from being hindered.

  Further, the fuel cell system according to the second aspect of the present invention reforms the hydrocarbon-based reforming raw material r1 by heat generated by burning the combustion fuel f, for example, as shown in FIG. A reformer 20 for generating a reformed gas g containing hydrogen; a fuel cell 60 for generating electricity by introducing an oxidant gas t containing oxygen and the reformed gas g; The reformed gas line 54 leading from the fuel cell 60 to the fuel cell 60, and the anode off-gas line 55 leading from the fuel cell 60 to the reformer 20 by using the anode off-gas p containing hydrogen not used for power generation in the fuel cell 60 as the combustion fuel f. The cathode offgas lines 57 and 58 that lead the cathode offgas q containing oxygen that has not been used for power generation in the fuel cell 60 to the outside of the system from the fuel cell 60 and the combustion fuel f are generated. The scan e and a gas-liquid separator 10 according to the first aspect of the present invention disposed on at least one exhaust gas line 53, 58 leading to the outside of the system from the reformer 20.

  With this configuration, even when the recovered water that is repeatedly used in the fuel cell system has a quality that allows fungi to grow, it is possible to suppress the inhibition of the flow of the recovered water, and the water independence in the fuel cell system can be reduced. Can be maintained.

  Further, the fuel cell system according to the third aspect of the present invention is shown in FIG. 1 and FIG. 3, for example. In the fuel cell system 100 according to the second aspect of the present invention, the container by the heating means 15 is used. The heating of the recovered water w stored in the lower portion of the fuel cell 11 is mainly performed when the fuel cell 60 is not generating power.

  If comprised in this way, the fall of the gas-liquid separation performance in a gas-liquid separator can be suppressed.

  According to the present invention, it is provided with heating means for giving the recovered water stored in the lower part of the container a heat quantity for sterilizing the fungi that cause the discharge of the recovered water from the container, and is stored in the lower part of the container. Fungi can be prevented from being generated in the recovered water, and even if it is generated, it can be sterilized and the discharge of recovered water from the container can be prevented from being hindered.

  Embodiments of the present invention will be described below with reference to the drawings. In the drawings, the same or similar members are denoted by the same or similar reference numerals, and redundant description is omitted.

  First, a gas-liquid separator 10 according to a first embodiment of the present invention will be described with reference to FIG. FIG. 1 is a longitudinal sectional view of the gas-liquid separator 10. The gas-liquid separator 10 is a device that introduces the mixed fluid Fm as a gas containing water vapor and condenses and separates the water vapor, and a container 11 that stores the water vapor condensed and separated from the mixed fluid Fm as recovered water w, and a container A drain mechanism 12 for discharging the recovered water w from the container 11 when the recovered water w stored in the tank 11 rises above a predetermined liquid level; and a heater 15 as a heating means for heating the recovered water w stored in the container 11; It has.

  The container 11 is typically formed in a cylindrical shape. Since the gas-liquid separator 10 is typically disposed such that the axis of the container 11 (cylindrical axis) formed in a cylindrical shape extends in the vertical direction, in the following description, the gas-liquid separator 10 has a positional relationship such as up and down. When mentioning it, the positional relationship in the typical arrangement of the gas-liquid separator 10 shall be said. A side protrusion 11a protruding outward is formed at the upper side of the container 11 and an inlet 11ha for introducing the mixed fluid Fm is formed at the tip of the side protrusion 11a.

  An upper surface protruding portion 11 b protruding upward is formed on the upper surface of the container 11, and a gas G from which water vapor corresponding to the recovered water w is separated from the mixed fluid Fm in the container 11 at the tip of the upper surface protruding portion 11 b. A gas outlet 11hb for leading out is formed. The upper surface protrusion 11 b also extends into the container 11. The length of the upper surface protrusion 11b extending into the container 11 is such that the mixed fluid Fm introduced from the introduction port 11ha collides with the outside of the upper surface protrusion 11b. By being configured in this manner, the mixed fluid Fm introduced into the container 11 collides with the upper surface protruding portion 11b (the upper surface protruding portion 11b of the portion where the mixed fluid Fm collides is particularly referred to as the “separating portion 13”. The recovered water w is condensed and separated from the mixed fluid Fm.

  On the bottom surface of the container 11, a lower surface protruding portion 11 c that slightly protrudes toward both the lower side and the inside of the container 11 is formed. A liquid outlet 11hc for leading the recovered water w separated from the mixed fluid Fm in the container 11 is formed at the tip of the lower surface protrusion 11c outside the container 11. The introduction port 11ha, the gas outlet port 11hb, and the liquid outlet port 11hc are respectively connected to a tubular member that forms a flow path for transporting fluid (mixed fluid Fm, gas G, recovered water w) with a screw or a flange. It is configured.

  The drain mechanism 12 is disposed in the container 11 and includes a float 12f, a spring 12s, and a disk 12d. The float 12 f is configured to receive buoyancy from the recovered water w stored in the container 11 and move up and down according to the liquid level of the recovered water w stored in the container 11. The spring 12s is typically a coil spring, and is connected to the lower part (including the bottom part) of the float 12f and the bottom part of the container 11 so as to bias the float 12f downward. The disk 12d closes the liquid outlet 11hc and can be opened and closed with respect to the liquid outlet 11hc (to permit and disallow the derivation of the recovered water w from the liquid outlet 11hc). ), Attached inside the container 11 in a single-opened shape. The disk 12d is connected to the float 12f by a lever 12r. The disk 12d opens when the float 12f rises, and the recovered water w can be led out from the liquid outlet 11hc. When the float 12f is positioned at the lower end, the disk 12d closes. The configuration is such that the recovered water w is not derived.

  Here, with reference to FIG. 2, the procedure in which the recovered water w stored in the container 11 is discharged will be described. 2, the periphery of the float 12f of the gas-liquid separator 10 is shown, and the upper portion (around the side protrusion 11a and the upper protrusion) is omitted. As shown in FIG. 2A, when there is no recovered water w in the container 11, the float 12f is lowered to the bottom of the container 11 by gravity and the pulling force of the spring 12s. At this time, the disk 12d connected to the float 12f via the lever 12r closes the liquid outlet 11hc. As shown in FIG. 2B, buoyancy is generated in the float 12f when the recovered water w accumulates in the container 11, but the float 12f is biased toward the bottom by the spring 12s, so the spring 12s. The float 12f does not rise until a buoyancy sufficient to overcome the pulling force is generated. When the float 12f does not rise and remains at the bottom, the recovered water w is led out from the container 11 because the liquid outlet 11hc is blocked by the disk 12d even if the recovered water w is accumulated in the container 11. Not. Then, as shown in FIG. 2 (c), a liquid level PL that generates buoyancy to overcome the pulling force of the spring 12s and raise the float 12f (this liquid level PL corresponds to a "predetermined liquid level"). When the level of the recovered water w in the container 11 rises, the float 12f rises and leaves the bottom. When the float 12f rises, the disk 12d connected through the lever 12r is opened, and the recovered water w stored in the container 11 is led out from the liquid outlet 11hc.

  Returning to FIG. 1 again, the description of the configuration of the gas-liquid separator 10 will be continued. The heater 15 is provided outside the container 11 so as to wrap the portion of the container 11 where the collected recovered water w exists from the highest liquid level of the recovered water w stored in the container 11 downward. . When the fungi that cause slimming of the recovered water w so as to hinder the recovery of the recovered water w from the liquid outlet 11hc are generated in the recovered water w stored in the container 11, the heater 15 It is configured to output the amount of heat that can sterilize fungi.

  Next, with reference to FIG. 3, a fuel cell system 100 according to a second embodiment of the present invention will be described. The fuel cell system 100 includes a reformer 20 that introduces a reforming material r1 as a hydrocarbon-based reforming material to generate a reformed gas g rich in hydrogen, and an oxidizing gas that contains reformed gas g and oxygen. The fuel cell 60 that introduces the agent gas t to generate power, the gas-liquid separator 10 described above, and the control device 90 that controls the operation of the fuel cell system 100 are configured.

  The reformer 20 introduces the reforming raw material r1 and the reforming water s, steam reforming the reforming raw material r1 to generate a gas rich in hydrogen, and carbon monoxide from the gas rich in hydrogen. The carbon monoxide reduction part 22 which produces | generates the reformed gas g which reduced the density | concentration, and the burner 25 which generate | occur | produces the reforming heat used for the steam reforming of the reforming raw material r1 are provided. Furthermore, the carbon monoxide reduction unit 22 introduces a shift unit 23 that converts carbon monoxide in a gas rich in hydrogen into a shift gas in which carbon monoxide is reduced from a gas rich in hydrogen, and a selective oxidation air a1. A selective oxidation unit 24 that selectively oxidizes carbon monoxide in the gas to generate a reformed gas g in which carbon monoxide is further reduced from the modified gas. The hydrocarbon-based reforming raw material (reforming raw material r1) is a general term for a hydrocarbon or a mixture containing hydrocarbon as a main component. Typically, a chain hydrocarbon such as methane or ethane (natural gas is also used). Or hydrocarbon-based fuels mainly composed of hydrocarbons such as methanol and petroleum products (kerosene, gasoline, naphtha, LPG, etc.). The gas rich in hydrogen is a gas mainly composed of hydrogen and contains 40% by volume or more, typically about 70 to 80% by volume of hydrogen. The reformed gas g obtained by reducing carbon monoxide from a gas rich in hydrogen also contains the same amount of hydrogen as the gas rich in hydrogen. The reformed gas g may have a hydrogen concentration of 80% by volume or more, that is, any concentration that enables power generation by an electrochemical reaction with oxygen in the oxidant gas t when supplied to the fuel cell 60. The reformed gas g contains water vapor. The gas rich in hydrogen typically contains about 10% by volume of carbon monoxide.

  The burner 25 is a part that introduces the combustion fuel f and the combustion air a2 and burns the combustion fuel f to obtain reforming heat necessary for steam reforming of the reforming raw material r1. As the combustion fuel f, hydrocarbon-based combustion fuel r2, anode off-gas p described later, or a mixture thereof is used. In the present embodiment, the combustion fuel r2 is the same material as the reforming raw material r1, and is changed to a name corresponding to the application for convenience of explanation. In order to prevent the combustion fuel f and combustion air a2 introduced into the burner 25 from mixing with the reforming raw material r1 and the reformed gas g flowing through the reforming unit 21 and the carbon monoxide reduction unit 22, The reforming unit 21 and the carbon monoxide reduction unit 22 are separated by a partition wall or the like. The burner 25 is disposed in the vicinity of the reforming unit 21 so that the reforming heat used for the steam reforming reaction in the reforming unit 21 can be efficiently given to the reforming unit 21.

  The fuel cell 60 is typically a polymer electrolyte fuel cell. The fuel cell 60 includes an anode 61 that introduces a reformed gas g, a cathode 62 that introduces an oxidant gas t, and a cooling unit 63 that removes heat generated by an electrochemical reaction. The oxidant gas t is typically air that has been humidified to a predetermined humidity. Although the fuel cell 60 is simply shown in the figure, in practice, a single cell is formed by sandwiching the solid polymer membrane between the anode 61 and the cathode 62, and this cell is interposed via the cooling unit 63. A plurality of layers are laminated. In the fuel cell 60, hydrogen in the reformed gas g supplied to the anode 61 is decomposed into hydrogen ions and electrons, and the hydrogen ions pass through the solid polymer film and move to the cathode 62, and the electrons It moves to the cathode 62 through a conducting wire (not shown) connecting to the cathode 62, reacts with oxygen in the oxidant gas t supplied to the cathode 62 to generate water, and generates heat during this reaction. In this reaction, the direct current can be taken out by passing electrons through the conducting wire. The fuel cell 60 is typically electrically connected to a power conditioner (not shown) that converts DC power into AC power.

  In the anode 61 of the fuel cell 60, not all of the hydrogen in the introduced reformed gas g is used for the above-described electrochemical reaction (power generation in the fuel cell 60), but some hydrogen is used. . From the anode 61, the anode off gas p containing hydrogen that has not been used for the electrochemical reaction in the fuel cell 60 is discharged. The anode off gas p contains hydrogen, carbon dioxide, nitrogen, water vapor and the like. At the cathode 62 of the fuel cell 60, not all of the oxygen in the introduced oxidant gas t is used for the above-described electrochemical reaction (power generation in the fuel cell 60), but some oxygen is used. . From the cathode 62, a cathode off-gas q containing oxygen that has not been used for the electrochemical reaction in the fuel cell 60 and water vapor is discharged.

  The selective oxidation unit 24 of the reformer 20 and the anode 61 of the fuel cell are connected by a reformed gas pipe 54 as a reformed gas line. In the reformed gas pipe 54, the gas-liquid separator 10 (hereinafter, the gas-liquid separator 10 disposed in the reformed gas pipe 54 is denoted by the reference sign when it is necessary to distinguish it from other gas-liquid separators. 10A ") is inserted and arranged. The gas-liquid separator 10A is preferably disposed in the vicinity of the fuel cell 60 from the viewpoint of introducing the reformed gas g into the gas-liquid separator 10A at a temperature as close as possible to the temperature when introduced into the fuel cell 60. . That is, in this way, it is avoided that the reformed gas g containing condensed water is introduced into the fuel cell 60 due to a decrease in the temperature of the reformed gas g derived from the gas-liquid separator 10A. can do. The gas-liquid separator 10A is disposed in the reformed gas pipe 54 so that the inlet 11ha is located on the selective oxidation unit 24 side and the gas outlet 11hb is located on the anode 61 side. One end of the reformed gas recovery water pipe 41 is connected to the liquid outlet 11hc of the gas-liquid separator 10A, and the other end is connected to the recovery water tank 85.

  The anode 61 of the fuel cell 60 and the burner 25 of the reformer 20 are connected by an anode offgas pipe 55 as an anode offgas line. The anode-off gas pipe 55 has a symbol “10B” when the gas-liquid separator 10 (hereinafter, the gas-liquid separator 10 disposed in the anode off-gas pipe 55 needs to be distinguished from other gas-liquid separators). Is inserted and arranged. The gas-liquid separator 10B is disposed in the anode off-gas pipe 55 so that the inlet 11ha is located on the anode 61 side and the gas outlet 11hb is located on the burner 25 side. One end of the anode off-gas recovery water pipe 42 is connected to the liquid outlet 11hc of the gas-liquid separator 10B, and the other end is connected to the recovery water tank 85. Since the gas-liquid separator 10B is disposed in the anode off-gas pipe 55, the anode off-gas p supplied to the burner 25 is not accompanied by excessive moisture, and misfire occurs when the anode off-gas p is burned. It is possible to avoid such inconveniences.

  The recovered water tank 85 is a tank that stores the recovered water w separated by each gas-liquid separator 10. The recovered water tank 85 is connected to a reforming water pipe 71 that guides the stored recovered water w to the reforming unit 21 as reforming water s. The reforming water pipe 71 is provided with a reforming water pump 81 that pumps the reforming water s from the recovered water tank 85 to the reforming unit 21.

  In addition to the reforming water pipe 71, the reforming part 21 is connected with a reforming raw material pipe 51a for introducing the reforming raw material r1. The reforming water pipe 71 may be connected to the reforming raw material pipe 51 a instead of being directly connected to the reforming section 21. The reforming raw material pipe 51a is a pipe branched from the raw material pipe 51 that conveys the raw material r. The other branched from the raw material pipe 51 is a combustion fuel pipe 51b. The combustion fuel pipe 51b is connected to the burner 25 which is a supply destination of the combustion fuel r2 to be conveyed. As described above, the reforming raw material r1 and the combustion fuel r2 are names in which the raw material r is distinguished depending on the application, and the physical properties are the same. The raw material pipe 51 may be provided with a desulfurizer 86 for desulfurizing the raw material r.

  In addition to the anode offgas pipe 55 and the combustion fuel pipe 51b, the burner 25 is connected with a combustion air pipe 52b for introducing the combustion air a2. The combustion fuel pipe 52b is a pipe branched from the air pipe 52 that carries the air a. The other branched from the air pipe 52 is a selective oxidation air pipe 52a. The selective oxidation air pipe 52a is connected to the selective oxidation unit 24 that is a supply destination of the selective oxidation air a1 to be conveyed. The selectively oxidized air a1 and the combustion air a2 are names that distinguish the air a according to the application. The burner 25 is connected to an exhaust gas pipe 53 as an exhaust gas line for discharging the combustion exhaust gas e generated after the combustion fuel f is burned. In the present embodiment, the exhaust gas pipe 53 penetrates the reforming part 21 (however, it does not communicate with the reforming part 21 (the exhaust gas e does not enter and exit the reforming part 21). )), The heat of the exhaust gas e can be used as reforming heat.

  Connected to the cathode 62 of the fuel cell 60 are an oxidant gas pipe 56 for introducing the oxidant gas t and a cathode offgas pipe 57 as a cathode offgas line for deriving the cathode offgas q. The cathode off gas pipe 57 is connected to the exhaust gas pipe 53. After the exhaust gas pipe 53 and the cathode offgas pipe 57 are connected, it becomes a single mixed exhaust gas pipe 58, and the mixed exhaust gas m in which the combustion exhaust gas e and the cathode offgas q are mixed is out of the system (outside the fuel cell system 100). It is configured to discharge. That is, the mixed exhaust gas pipe 58 serves as both the exhaust gas pipe 53 and the cathode offgas pipe 57. The mixed exhaust gas pipe 58 has a gas-liquid separator 10 (hereinafter referred to as “10C” when the gas-liquid separator 10 disposed in the mixed exhaust gas pipe 58 needs to be distinguished from other gas-liquid separators. Is shown). From the viewpoint of introducing the mixed exhaust gas m into the gas-liquid separator 10C at the lowest possible temperature, the gas-liquid separator 10C is preferably disposed in the vicinity of an exhaust port (not shown) that discharges the mixed exhaust gas m out of the system. . In other words, in this case, the combustion exhaust gas e having a relatively high temperature is mixed with the cathode off gas q having a relatively low temperature, and the temperature is further lowered by heat radiation, and then the water vapor is removed by the gas-liquid separator 10C. Therefore, when the temperature of the mixed exhaust gas m derived from the gas-liquid separator 10C decreases, the moisture in the mixed exhaust gas m is condensed and the mixed exhaust gas m discharged from the exhaust port (not shown) is “white smoke”. Can be avoided. The gas-liquid separator 10C is disposed in the mixed exhaust gas pipe 58 so that the inlet 11ha is located on the reformer 20 and the fuel cell 60 side, and the gas outlet 11hb is located outside the system. One end of the exhaust gas recovery water pipe 43 is connected to the liquid outlet 11hc of the gas-liquid separator 10C, and the other end is connected to the recovery water tank 85.

  The cooling unit 63 of the fuel cell 60 is connected to a cooling water pipe 73 through which the cooling water c that takes away heat generated by the electrochemical reaction flows. The cooling water pipe 73 is provided with a heat exchanger 88 that radiates heat of the cooling water c. The heat released by the heat exchanger 88 is typically stored in a hot water tank (not shown) through a heat medium (not shown) such as exhaust heat recovery water. The cooling water pipe 73 includes a first cooling water pipe 73A that guides the cooling water c from the cooling section 63 to the heat exchanger 88, and a second cooling water pipe 73B that guides the cooling water c from the heat exchanger 88 to the cooling section 63. Has been. The second cooling water pipe 73B is provided with a cooling water pump 83 for circulating the cooling water c in the cooling water pipe 73. In addition, a cooling water replenishment pipe 78 that replenishes the cooling water pipe 73 with cooling water is connected to the second cooling water pipe 73 </ b> B upstream of the cooling water pump 83. The other end of the cooling water replenishment pipe 78 is connected to the bottom of the recovered water tank 85 so that the recovered water w collected in the recovered water tank 85 can be used for replenishing the cooling water c. .

The control device 90 is connected to the reforming raw material r1, the combustion fuel f, and the reforming water s introduced into the reformer 20.
And the like, by adjusting a valve (not shown), the reforming water pump 81, and the like, the operation of the reformer 20 (the generation amount of the reformed gas g) can be controlled. ing. The control device 90 controls the operation of the fuel cell 60 by controlling the flow rates of the reformed gas g and the oxidant gas t introduced into the fuel cell 60 by adjusting valves (not shown), an oxidant gas blower, and the like. (Generated power) can be controlled. Further, the control device 90 is configured to be able to control the start / stop and rotation speed of the cooling water pump 83. Moreover, the control apparatus 90 is comprised so that the output of the heater 15 (refer FIG. 1) of the gas-liquid separator 10 can be adjusted (a stop state is also included).

  The operation of the gas-liquid separator 10 and the fuel cell system 100 will be described with reference to FIGS. The operation of the gas-liquid separator 10 will be described as part of the operation of the fuel cell system 100. In order to start the fuel cell system 100 from a stopped state, the reforming material 21 is supplied with the reforming raw material r1 and the reforming water s, and the combustion fuel r2 and the combustion air a2 as the combustion fuel f are supplied to the burner 25. Supply. By burning the combustion fuel r2 by the burner 25 to generate reforming heat, the reforming raw material r1 supplied to the reforming section 21 is reformed into a gas rich in hydrogen by a steam reforming reaction. The gas rich in hydrogen is a gas rich in hydrogen that undergoes a transformation reaction in the transformation unit 23 and a selective oxidation reaction in the selective oxidation unit 24 using the introduced selective oxidation air a1 to reduce the carbon monoxide concentration. It becomes the reformed gas g. Since the reformed gas g is reformed at a relatively high S / C (ratio of steam to carbon) in the reforming section 21, the steam is almost saturated. On the other hand, the combustion exhaust gas e generated by burning the combustion fuel f in the burner 25 is discharged from the reformer 20 and flows in the exhaust gas pipe 53.

  The reformed gas g generated in the reformer 20 flows into the gas-liquid separator 10A while being guided to the anode 61. The reformed gas g that has flowed into the gas-liquid separator 10A collides with the separation unit 13, the water vapor in the reformed gas g is condensed and separated, and stored in the container 11 as recovered water w. The recovered water w stored in the container 11 is derived from the gas-liquid separator 10A and stored in the recovered water tank 85 when it exceeds a predetermined liquid level PL. On the other hand, the reformed gas g from which the steam for the recovered water w has been separated is led out from the gas outlet 11hb and introduced into the anode 61. In addition, since the composition of the reformed gas g produced is not stable at the beginning of the reformer 20, the reformed gas g with an unstable composition is introduced into the anode 61 after being derived from the gas-liquid separator 10A. Instead, it is preferable to guide the burner 25 through the bypass pipe (not shown) and the anode off-gas pipe 55 and burn it, and use the heat generated by the combustion as the reforming heat.

When the reformed gas g is introduced into the anode 61, the controller 90 activates an oxidant gas blower (not shown) and supplies the oxidant gas t to the cathode 62. In the fuel cell 60 to which the reformed gas g and the oxidant gas t are supplied, the following electrochemical reaction is performed. As for the electrochemical reaction, the reaction represented by the following formula (1) is performed at the anode 61, and the reaction represented by the following formula (2) is performed at the cathode 62.
2H ₂ → 4H ⁺ + 4e ⁻ (1)
O ₂ + 4H ⁺ + 4e ⁻ → 2H ₂ O (2)
Electricity is generated by this electrochemical reaction, heat is generated, and moisture is generated. In further explanation, electric power can be obtained when electrons of the anode 61 move to the cathode 62 through an external electric circuit (not shown). Hydrogen ions of the anode 61 pass through the solid polymer film and move to the cathode 62, and combine with oxygen to generate moisture. As mentioned above, this electrochemical reaction is an exothermic reaction.

  The electric power obtained by the fuel cell 60 is direct-current power, which is converted into alternating-current power by a power conditioner (not shown) as necessary and transmitted to an electric power load (not shown). On the other hand, the heat generated in the fuel cell 60 is stored in, for example, a hot water storage tank (not shown) using the cooling water c for cooling the fuel cell 60 and the exhaust heat recovery water (not shown) as a medium. Consumed under heat load such as heating. By effectively using the heat generated in the fuel cell 60, the efficiency of the fuel cell system 100 is improved. The anode offgas p derived from the anode 61 after the electrochemical reaction in the fuel cell 60 flows into the gas-liquid separator 10B while being guided to the burner 25. The anode off-gas p flowing into the gas-liquid separator 10B collides with the separation unit 13, and the water vapor in the anode off-gas p is condensed and separated and stored in the container 11 as recovered water w. The recovered water w stored in the container 11 is led out from the gas-liquid separator 10B and stored in the recovered water tank 85 when it exceeds a predetermined liquid level PL. On the other hand, the anode off gas p from which the water vapor for the recovered water w has been separated is led out from the gas outlet 11hb and introduced into the burner 25. The anode off gas p introduced into the burner 25 is burned as the combustion fuel f and generates reforming heat. When the combustion fuel f is sufficient with the anode off-gas p (when necessary reforming heat can be obtained), the supply of the combustion fuel r2 to the burner 25 is stopped, and even when the anode off-gas p is insufficient, there is a shortage. The combustion fuel r2 is reduced to the supplementary flow rate. When the anode off gas p is combusted, hydrogen in the anode off gas p is combined with oxygen to generate water, and the generated water flows in the exhaust gas pipe 53 in a state of being contained in the combustion exhaust gas e as water vapor.

  On the other hand, the cathode offgas q derived from the cathode 62 after the electrochemical reaction in the fuel cell 60 merges with the combustion exhaust gas e discharged from the burner 25 to become a mixed exhaust gas m and flows in the mixed exhaust gas pipe 58. The mixed exhaust gas m flows into the gas-liquid separator 10C before being discharged out of the system. The mixed exhaust gas m flowing into the gas-liquid separator 10 </ b> C collides with the separation unit 13, and water vapor in the mixed exhaust gas m is condensed and separated and stored in the container 11 as recovered water w. The recovered water w stored in the container 11 is derived from the gas-liquid separator 10C and stored in the recovered water tank 85 when it exceeds a predetermined liquid level PL. On the other hand, the mixed exhaust gas m from which water vapor for the recovered water w has been separated is discharged out of the system.

  The recovered water w recovered from each of the gas-liquid separators 10A, 10B, and 10C in the recovered water tank 85 is supplied to the reforming unit 21 as reforming water s and is used again in the fuel cell system 100. Thus, by using the recovered water w separated and recovered by the gas-liquid separator 10 in the fuel cell system 100, water independence can be achieved. In addition, when the moisture in the fuel cell system 100 decreases due to the carry over of the moisture outside the system and the recovered water w in the recovered water tank 85 decreases, the recovered water tank 85 is replenished with water from outside the system. Is done.

  When the fuel cell system 100 is not activated, the mixed fluid Fm (the reformed gas g, the anode offgas p, and the mixed exhaust gas m) does not flow into each gas-liquid separator 10, so that new water vapor is separated. I will not. If the separation of new water vapor is not performed, the amount of the recovered water w in the container 11 does not increase, so that the state in which the recovered water w is not discharged from the container 11 is maintained. At this time, the recovered water w having a liquid level equal to or lower than the predetermined liquid level PL is stored in the container 11. And although the temperature of the collection | recovery water w stored in the container 11 has exceeded 80 degreeC immediately after isolate | separating with each gas-liquid separator 10, it falls as time passes. If the recovered water w stored in the container 11 stays at around 40 ° C. (for example, about 35 to 45 ° C.), the fungi are likely to propagate. If the fungus grows in the recovered water w, the fungus becomes slime, and the derivation of the recovered water w from the liquid outlet 11hc of the gas-liquid separator 10 may be hindered.

  Therefore, the controller 90 energizes the heater 15 of the gas-liquid separator 10 and stores it in the container 11 before the fungus grows so that the derivation of the recovered water w from the liquid outlet 11hc is inhibited. The recovered water w is heated to sterilize. “Sterilization” is typically sterilization to such an extent that inhibition of derivation of the recovered water w from the liquid outlet 11hc does not occur. When performing sterilization, the control device 90 adjusts the output of the heater 15 so that the amount of heat necessary for sterilization can be given from the heater 15 to the recovered water w stored in the container 11. The amount of heat necessary for sterilization is, for example, the amount of heat that allows the recovered water w stored in the container 11 to continue at a temperature of 70 ° C. or higher for 15 minutes. The timing for performing sterilization may be performed, for example, when a predetermined time elapses after power generation in the fuel cell 60 is stopped. The “predetermined time” is typically a time that is less than the time during which the recovered water w stored in the container 11 is retained to such an extent that the fungus grows so that the discharge out of the liquid outlet 11hc is inhibited. And as long as possible. The reason why the time is as long as possible is to avoid starting the heater 15 as much as possible from the viewpoint of reducing power consumption and maintaining the gas-liquid separation performance in the gas-liquid separator 10.

  The timing for sterilization may be immediately after the fuel cell system 100 is activated. In this case, if the time during which the recovered water w is stored in the container 11 exceeds the predetermined time, the fungus may propagate so that the recovery of the recovered water w from the liquid outlet 11hc is inhibited. However, after the fuel cell system 100 is started, the mixed fluid Fm (reformed gas g, anode offgas p) containing water vapor to be separated after reaching a steady operation in which the reformer 20 and the fuel cell 60 exhibit their planned capabilities. Since there is a time lag until the mixed exhaust gas m) is introduced into the gas-liquid separator 10, there is no hindrance to the recovery of the recovered water w before the recovered water w separated by the gas-liquid separator 10 overflows from the container 11. As such, sterilization can be performed.

  As described above, according to the fuel cell system 100 according to the present embodiment, the amount of heat for sterilizing the fungi that hinder the discharge of the recovered water w from the container 11 is stored in the lower part of the container 11. Since the gas-liquid separator 10 having the heater 15 for supplying the recovered water w is provided, it is possible to sterilize even when fungi are generated in the recovered water w stored in the lower part of the container 11. The discharge of the recovered water w from the container 11 can be prevented from being hindered, and a stable operation can be performed.

  In the above description, the container 11 is formed in a cylindrical shape. However, the shape of the cross section perpendicular to the axis may be a hollow polygonal column formed in a polygon such as a quadrangle or an octagon.

  In the above description, the drain mechanism 12 has the float 12f and the disk 12d, but instead of these, an electromagnetic valve that can open and close the liquid outlet 11hc and a liquid level that can detect the liquid level in the container 11 A detector may be provided, and the control device 90 may perform control so that the electromagnetic valve is opened when the liquid level detector detects a liquid level exceeding a predetermined liquid level PL. Whether the drain mechanism 12 has a float 12f or a solenoid valve determines the properties of the mixed fluid Fm (reformed gas g, anode offgas p, mixed exhaust gas m) for each of the gas-liquid separators 10A, 10B, and 10C. What is necessary is just to determine suitably in consideration.

  In the above description, the lower part (including the bottom part) of the float 12f and the bottom part of the container 11 are connected by the spring 12s so as to urge the float 12f downward, but the liquid outlet 11hc is closed. The disk 12d and the bottom of the container 11 may be connected by a spring 12s so as to bias the disk 12d in the direction.

  In the above description, the heater 15 as the heating means is provided outside the container 11. However, if the recovered water w stored in the container 11 can be heated to a temperature at which it can be sterilized, It may be provided (for example, a heating element is provided in the lower part of the container 11), or a heating means other than the heater 15 (for example, a jacket type heat exchanger for flowing a fluid inside) may be used. .

  In the above description, the gas-liquid separator 10C is provided in the mixed exhaust gas pipe 58 that also serves as the exhaust gas pipe 53 and the cathode off-gas pipe 57. However, the gas-liquid separation is performed in each of the exhaust gas pipe 53 and the cathode off-gas pipe 57. A vessel 10 may be provided. At this time, instead of connecting the exhaust gas pipe 53 and the cathode offgas pipe 57 to form the mixed exhaust gas pipe 58, the exhaust gas pipe 53 and the cathode offgas pipe 57 may be separately led out of the system. However, from the viewpoint of reducing the installation space and efficiently reducing the temperature of the gas discharged outside the system, it is assumed that the gas-liquid separator 10C is provided in the mixed exhaust gas pipe 58 that also serves as the exhaust gas pipe 53 and the cathode offgas pipe 57. Good.

It is a longitudinal cross-sectional view of the gas-liquid separator which concerns on the 1st Embodiment of this invention. It is a figure explaining the effect | action of the gas-liquid separator which concerns on the 1st Embodiment of this invention. It is a systematic diagram of the fuel cell system which concerns on the 2nd Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Gas-liquid separator 11 Container 12 Drain mechanism 15 Heating means 20 Reformer 53 Exhaust gas line 54 Reformed gas line 55 Anode offgas line 57 Cathode offgas line 58 Mixed exhaust gas line 60 Fuel cell 100 Fuel cell system Fm Mixed fluid e Exhaust gas f Fuel for combustion g Reformed gas p Anode off gas q Cathode off gas r1 Reforming raw material t Oxidant gas w Recovered water

Claims (3)

A container that introduces a gas containing water vapor, condenses and separates the water vapor, and stores it in the lower part;
A drain mechanism for discharging the recovered water from the container when the recovered water, which is stored in the lower part of the container and from which the water vapor is condensed and separated, rises above a predetermined liquid level;
Heating means for giving heat to the recovered water stored in the lower part of the container with an amount of heat for sterilizing fungi that inhibits discharge of the recovered water from the container;
Gas-liquid separator. A reformer for reforming a hydrocarbon-based reforming raw material to generate reformed gas containing hydrogen by heat generated by burning combustion fuel;
A fuel cell for generating electricity by introducing an oxidant gas containing oxygen and the reformed gas;
A reformed gas line for guiding the reformed gas from the reformer to the fuel cell, an anode off-gas containing hydrogen not used for power generation in the fuel cell as the combustion fuel from the fuel cell to the reformer An anode off-gas line that leads to the cathode, a cathode off-gas line that leads the cathode off-gas containing oxygen that has not been used for power generation in the fuel cell to the outside from the fuel cell, and exhaust gas generated by burning the combustion fuel A gas-liquid separator according to claim 1, wherein the gas-liquid separator is disposed in at least one of exhaust gas lines leading from the reformer to the outside of the system;
Fuel cell system. The heating of the recovered water stored in the lower part of the container by the heating means is configured to be performed mainly when power generation of the fuel cell is not performed;
The fuel cell system according to claim 2.

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