JP5942692B2 - Fuel cell power generator - Google Patents

Description

  The present invention relates to a fuel cell power generator that is provided with a cooler that cools a fuel cell adjacent to the fuel cell, and cools the fuel cell by flowing at least part of the exhaust gas after heat exchange in the cooler. is there. In particular, a fuel cell power generator that cools a fuel cell using exhaust gas after passing through a heat exchanger (such as a reformer) or after preheating air of a solid oxide fuel cell (also referred to as SOFC) About.

  When a power generation chamber cooling line is added to the SOFC that constitutes a fuel cell, the air that is the fluid used for cooling the power generation chamber is supplied to the power generation chamber as it is in consideration of the operating cost and efficiency of the SOFC. Can be considered.

  However, in this method, since the flow rate of the cooling air used for cooling the power generation chamber is equal to the flow rate of the power generation air supplied to the power generation chamber, it may be difficult to adjust the temperature inside the power generation chamber. .

  In other words, the amount of cooling air, which is a parameter for temperature adjustment, and the amount of air for power generation are the same and cannot be adjusted individually. Becomes difficult.

  Moreover, in order to increase the system efficiency of SOFC, it is desirable to reduce the total amount of air including the amount of cooling air and the amount of power generation air. However, if the amount of cooling air and the amount of power generation air are simultaneously reduced, it may be difficult to keep the temperature of the power generation chamber within an appropriate range.

  That is, when the amount of power generation air is reduced, the heat that has been carried outside by the power generation air is reduced, and the temperature of the power generation chamber is increased. In order to suppress this temperature rise, it is necessary to increase the amount of cooling air. Therefore, if the amount of cooling air and the amount of power generation air are reduced at the same time, the temperature of the power generation chamber will deviate from the proper range, while if the temperature of the power generation chamber is kept within the proper range, There is a problem that it becomes difficult to reduce the amount of air and the amount of power generation air.

  The solid oxide fuel cell described in Patent Document 1 has been made in order to solve the above-described problems, and is an amount of air supplied to the power generation chamber and the amount of air used for cooling the power generation chamber. Provided is a solid oxide fuel cell that can reduce the total amount and easily adjust the temperature inside the power generation chamber.

  In Patent Document 1, a power generation chamber in which a plurality of power generation cells that generate power are housed, a cooling unit that is arranged in thermal connection with the power generation chamber, and air that supplies air used for power generation in the power generation cell And a supply unit.

  Further, there are provided a branch part that guides at least a part of the air flowing through the air supply part to the cooling part, and a cooling adjustment part that controls the flow rate of the air flowing through the air supply part and the branch part. As a result, the total amount of air supplied to the power generation chamber and the amount of air used for cooling the power generation chamber can be reduced, and the temperature inside the power generation chamber can be easily adjusted. Is obtained.

JP 2010-140750 A

  In Patent Document 1, a part of the air to the cathode side (a part of the air in the cathode line) is introduced into a cooler to reduce the total amount of air. Further, a part of the air to the cathode side is branched and used for cooling, thereby reducing the amount of air and facilitating temperature adjustment in the power generation chamber. However, if the cooling air is supplied by branching from the cathode line, it becomes difficult to adjust the temperature of the cooling air itself even if the temperature inside the power generation chamber can be easily adjusted. In other words, since a part of the air is branched and used for power generation and cooling, the original air temperature itself is the same, and the temperature of the cooling air cannot be adjusted well only by controlling the flow rate. is there. Therefore, it is desirable to cool the cooler with a gas other than the power generation air.

  The present invention has been made paying attention to such problems existing in the prior art, and its purpose is to cool the cooler with a gas other than the air for power generation. An object of the present invention is to obtain a fuel cell power generator that can be easily cooled by a cooler without being directly affected by the temperature of the air used.

  Descriptions of patent documents listed as prior art can be introduced or incorporated by reference as explanations of technical elements described in this specification.

In order to achieve the above object, the present invention employs the following technical means. That is, in the invention described in the claims, the fuel cell (1) that is operated by being supplied with fuel and air, the cooler (7) that cools the fuel cell (1), and the fuel and air that have passed through the fuel cell (1) Combustor (3) that is supplied and burns, heat exchanger for fuel (2) that heats the fuel before being supplied to the fuel cell (1) by the heat of the exhaust of the combustor (3), heat exchange for fuel Fuel cell cooling pipes (10a, 10b) for flowing at least a part of the exhaust gas of the combustor (3), whose temperature is lower than the operating temperature of the fuel cell (1) by heat exchange with the combustor (2), to the cooler (7) And an air heat exchanger (6) for heating the air before being supplied to the fuel cell (1) by the heat of the exhaust gas from the combustor (3), and the fuel heat exchanger (2). Of the combustor (3) whose temperature is lower than the operating temperature of the fuel cell (1) due to heat exchange with At least a portion of the air, is characterized by comprising a fuel cell cooling pipe flow to the cooler (7) air heat exchanger via a (6) (10b).
Also, a fuel cell (1) that is operated by being supplied with fuel and air, a cooler (7) that cools the fuel cell (1), and a combustor that is supplied with fuel and air that has passed through the fuel cell (1) and combusts. (3) Heat exchange with the fuel heat exchanger (2) and the fuel heat exchanger (2) for heating the fuel before being supplied to the fuel cell (1) by the heat of the exhaust gas from the combustor (3) Is provided with fuel cell cooling pipes (10a, 10b) for flowing at least a part of the exhaust gas of the combustor (3), which has fallen below the operating temperature of the fuel cell (1), to the cooler (7), and heat exchange for fuel Exhaust pumping means (17) for pumping at least a part of the exhaust gas of the combustor (3) whose temperature is lower than the operating temperature of the fuel cell (1) by heat exchange with the cooler (2) to the cooler (7). It is characterized by providing .

  According to the present invention, the fuel that flows at least a part of the exhaust of the combustor whose temperature is lower than the operating temperature of the fuel cell by heat exchange with the fuel heat exchanger to the air heat exchanger via the cooler Since the battery cooling pipe is provided, the cooler can be cooled by the exhaust of the combustor, which is a gas different from the air for power generation, and it is not directly affected by the temperature of the air for power generation. It becomes easy to carry out the temperature adjustment.

  In the invention described in the claims, the exhaust gas from the combustor (3) whose temperature is lower than the operating temperature of the fuel cell (1) due to heat exchange with the fuel heat exchanger (2), and the pressure pump to the cooler (7) The exhaust gas feeding means (17) for pumping at least a part of the mixed exhaust gas mixed with the exhaust gas passed through the cooler (7) to the cooler (7) is provided.

  According to the present invention, at least a part of the mixed exhaust gas after the combustor exhaust gas is mixed with the exhaust gas that has passed through the cooler is supplied to the cooler via the exhaust pressure feeding means composed of, for example, a blower. Thus, the temperature of the exhaust gas, which is a cooling gas supplied to the cooler, can be supplied at a temperature closer to the operating temperature of the fuel cell, and thermal shock can be reduced.

  In the invention described in the claims, a downstream heat exchanger (6) that is provided downstream of the exhaust after heat exchange with the fuel heat exchanger (2) and absorbs heat from the exhaust, and a downstream heat exchanger ( 6) Exhaust discharge means (22 to 24) for discharging the heat absorbed by the atmosphere into the atmosphere, and the exhaust pressure sending means (17) includes the high-temperature exhaust gas that has passed through the fuel heat exchanger (2) and the downstream heat. The cooler (7) while selectively sucking the low-temperature exhaust gas that has passed through the exchanger (6) through a plurality of exhaust pumping means side valves (26, 27) arranged on the exhaust pumping means (17) side. It is characterized by being supplied to.

  According to this invention, the temperature of the exhaust gas sucked by the exhaust pressure feeding means can be controlled by controlling the exhaust pressure feeding means side valve, so that the temperature of the exhaust gas supplied to the cooler can be adjusted.

  In the invention described in the claims, the plurality of cooler side valves (31, 32) arranged on the secondary side of the cooler (7) are exhausted by being pumped to the cooler (7) and passing through the cooler (7). ) To selectively mix either the high-temperature exhaust gas that has passed through the fuel heat exchanger (2) and the low-temperature exhaust gas that has passed through the downstream heat exchanger (6). The mixed exhaust gas is supplied to the cooler (7) while being selectively sucked by the exhaust pressure feeding means (17) through a plurality of exhaust pressure feeding means side valves (26, 27).

  According to the present invention, the temperature of the exhaust gas supplied to the cooler can be controlled not only by the exhaust pressure feeding means side valve but also by the cooler side valve. Further, not only the high-temperature exhaust gas that has passed through the fuel heat exchanger, but also a part of the low-temperature exhaust gas that has passed through the downstream heat exchanger is allowed to flow to the cooler, and the temperature of the cooler is adjusted to the exhaust pressure feeding means side valve and Fine control is possible with the cooler side valve.

  In addition, the code | symbol in parentheses described in a claim and each said means is an example which shows the correspondence with the specific means as described in embodiment mentioned later easily, and limits the content of invention is not.

1 is a piping system diagram showing a first embodiment of a fuel cell power generator of the present invention. It is a piping system diagram which shows 2nd Embodiment of this invention fuel cell electric power generating apparatus. It is a piping system diagram showing a third embodiment of the fuel cell power generator of the present invention. It is a piping system diagram which shows 4th Embodiment of this invention fuel cell electric power generating apparatus. It is a piping system diagram showing a fifth embodiment of the fuel cell power generator of the present invention. It is a piping system diagram which shows 6th Embodiment of this invention fuel cell electric power generating apparatus. It is a piping system diagram showing a seventh embodiment of the fuel cell power generator of the present invention.

  A plurality of modes for carrying out the present invention will be described below with reference to the drawings. In each embodiment, parts corresponding to the matters described in the preceding embodiment may be denoted by the same reference numerals, and redundant description may be omitted. When only a part of the configuration is described in each mode, the other modes described above can be applied to the other parts of the configuration.

  Not only combinations of parts that clearly indicate that the combination is possible in each embodiment, but also the embodiments are partially combined even if they are not clearly specified unless there is a problem with the combination. It is also possible.

(First embodiment)
Hereinafter, a first embodiment of the present invention will be described in detail. In FIG. 1, a fuel cell 1 made of SOFC (solid oxide fuel cell) in the fuel cell power generation apparatus 100 uses ceramics forming an ion conductive oxide as an electrolyte.

  This fuel cell 1 has a positive electrode (also referred to as an anode or a fuel electrode, also referred to as An) and a negative electrode (also referred to as a cathode or air electrode, also referred to as Ca) as electrodes. These electrodes are made of conductive ceramics. A solid electrolyte is provided between the anode and the cathode. Air is supplied to the cathode. Hydrogen or carbon monoxide CO is supplied to the anode. These hydrogen and CO are made from hydrocarbon fuel (such as city gas methane).

  Fuel is supplied by a pump. The reforming reaction mainly includes steam reforming and partial oxidation reforming. Taking steam reforming as an example, the fuel is mixed with steam and sent to the reformer 2 as steam.

  The fuel before reforming may be referred to as a pre-reforming raw material, and the fuel after reforming may be referred to as a reformed fuel. The raw material before reforming is reformed by the reforming reaction in the reformer 2 (endothermic reaction in the case of steam reforming) and decomposed into hydrogen and CO. Of course, other products are formed. It is necessary to supply heat for the endothermic reaction during the reforming.

  The means for supplying heat to the reformer 2 comprises a combustor 3. Heat is extracted from the combustion gas from the combustor 3 by the heat exchanger in the reformer 2. The fuel cell 1 does not consume all the fuel, but partially unreacted hydrogen and CO are released from the fuel cell 1.

  The released hydrogen and CO are burned in the combustor 3 together with the remaining air. In this way, heat is generated in the combustor 3 and supplied to the reformer 2 to cause a reforming reaction. In addition, the heat can be supplied using the heat generated by the fuel cell 1.

  The combustion gas emitted from the combustor 3 is used to preheat fuel and air in a heat exchanger called a reformer 2, a fuel preheater 4, a first second air preheater 5, 6 and the like. For example, the air temperature rises in the first and second air preheaters 5 and 6. The preheated air is supplied to the fuel cell 1. The purpose of preheating is that the fuel cell operates at a relatively high temperature (700 ° C. to 800 ° C.). This is because if the supplied air temperature is too lower than the operating temperature of the fuel cell 1, the temperature distribution is generated in the fuel cell 1 and the power generation efficiency deteriorates.

  The fuel cell 1 is generally made of ceramic. If air at room temperature enters a ceramic at 700 ° C. to 800 ° C., there is a risk of cracking due to thermal shock. Accordingly, air or the like preheated to some extent is supplied to the fuel cell 1. Preheated air or the like passes through the combustor 3 from the fuel cell 1, and further comprises air comprising fuel preheating means 2 and 4, which are called a reformer 2 and a fuel preheater 4, and first and second air preheaters 5 and 6. It passes through the preheating means 5 and 6 and is discharged into the atmosphere.

  As described above, the fuel cell power generation apparatus 100 includes the solid electrolyte fuel cell 1 that generates power by supplying fuel and air. The fuel cell 1 is provided with an electrode composed of an anode and a cathode. These electrodes and electrolyte are both made of ceramic or a composite of ceramic and metal.

  The fuel is supplied to the anode through an anode line serving as a pipe through which the fuel supplied to the fuel cell 1 flows. The anode line has an inlet side through which fuel flows into the fuel cell 1 and an outlet side through which fuel flows out to the fuel cell 1.

  Furthermore, air is supplied to the cathode via an air pump (not shown) and first and second air preheaters 5 and 6. Further, the anode is supplied with fuel to the fuel cell 1 via the fuel preheater 4 and the reformer 2 via a fuel pump (not shown).

  The reformer 2 is a reaction device that extracts hydrogen from fuels such as natural gas, methanol, and gasoline, and reforms the raw material before reforming into reformed fuel by the heat of the combustion gas from the combustor 3. In this embodiment, steam and city gas are used as raw materials before reforming. In the reforming reaction, the raw material before reforming (raw gas) is supplied so that the ratio of carbon 1 to water 3 (S / C = 3/1), for example.

  Further, water vapor is supplied to the anode via a water pump (not shown), the fuel preheater 4 and the reformer 2. The fuel cell main body 2 has a temperature sensor that constitutes anode temperature detection means (not shown) that detects the temperature of the anode.

  The air that has passed through the cathode in the fuel cell 1 and the fuel that has passed through the anode are sent to the combustor 3 where the fuel is combusted. Exhaust gas composed of high-temperature combustion gas passes through the reformer 2 and drops in temperature, and then passes through the cooler 7 to cool the fuel cell 1. The exhaust is discharged into the atmosphere via the second air preheater 6, the fuel preheater 4, and the first air preheater 5.

  As described above, at least a part (all in the first embodiment) of the exhaust gas from the combustor 3 whose temperature is lower than the operating temperature of the fuel cell 1 due to the heat exchange with the reformer 2 serving as a fuel heat exchanger. The fuel cell cooling pipes 10a and 10b are supplied to the second air preheater 6 serving as an air heat exchanger via the cooler 7. Of the fuel cell cooling pipes 10a and 10b, 10a is a primary side fuel cell cooling pipe and 10b is a secondary side fuel cell cooling pipe.

  Furthermore, it is possible to directly generate power using hydrogen instead of natural gas or coal gas. When reforming of fuel is not required as in the case of using hydrogen, the reformer 2 may be omitted. In this case, the hottest heat exchanger (air preheater or fuel preheater) is arranged instead of the reformer.

  As can be seen from FIG. 1, the first air preheater 5 is supplied with air by an external air pump (not shown). Further, the first air preheater 5 is supplied with combustion gas via the fuel preheater 4. The high-temperature combustion gas and air that have passed through the fuel preheater 4 are heat-exchanged in the first air preheater 5.

  Further, the air from the first heat exchanger 5 is supplied to the second air preheater 6. Further, on the secondary side of the second air preheater 6, temperature adjustment air for adjusting the temperature of the fuel cell 1 is added. Next, the combustion gas that has passed through the reformer 2 is supplied to the second air preheater 6. The high-temperature combustion gas and air that have passed through the reformer 2 are heat-exchanged in the second air preheater 6.

  In the above configuration, since the cooler 7 is cooled by the exhaust gas after passing through the reformer 2 of the combustor 3, the fuel cell 1 is compared with the concept of cooling the cooler 7 using the air of the cathode line. The amount of air in the cathode line can be reduced. By reducing the amount of air, an effect of reducing blower power and an effect of reducing exhaust heat loss are exhibited. Even if exhaust is performed at the same temperature when the amount of air is large, the heat loss increases as the flow rate increases. Therefore, the reduction of the air amount contributes to the reduction of the exhaust heat loss.

  Note that if the fuel cell 1 is all cooled with air, it is necessary to supply about ten times as much air as that required for power generation. Therefore, cooling with the exhaust gas after passing through the reformer 2 of the combustor 3 can greatly reduce the amount of air supplied.

  And the amount of heat required to raise the temperature of the fuel cell 1 to the same temperature decreases due to the influence of the decrease in the amount of air. The exhaust of the fuel cell 1 also has the same amount of heat as the air flow rate is reduced, and the temperature of the exhaust rises. In the heat exchanger using the exhaust whose temperature has increased, heat exchange is easy. Become. Therefore, the first and second heat exchangers 5 and 6 and the fuel preheater 4 that exchange heat with exhaust gas whose temperature has increased can be reduced in size.

  In particular, the amount of heat required to raise the temperature to the same temperature is reduced due to the effect of reducing the amount of air passing through the first air preheater 5. Furthermore, if the exhaust gas passing through the first air preheater 5 has the same amount of heat as the air flow rate is reduced, the exhaust temperature rises, and the air and exhaust gas in the first air preheater 5 There is an effect that heat exchange is facilitated.

(Operational effects of the first embodiment)
As described above, the first embodiment includes the fuel cell 1 that is supplied with fuel and air and operates at the operating temperature. Also, a cooler 7 that cools the fuel cell 1, a combustor 3 that is supplied with fuel and air that has passed through the fuel cell 1 and combusts, and before being heated and supplied to the fuel cell 1 by the exhaust of the combustor 3 It has the reformer 2 used as the heat exchanger 2 for fuel which heats this fuel.

  Then, at least a part of the exhaust of the combustor 3 whose temperature is lower than the operating temperature of the fuel cell 1 due to heat exchange with the fuel heat exchanger 2 is passed through the cooler 7 to the second air heat exchanger. Fuel cell cooling pipes 10a and 10b are provided.

  According to this, at least a part (or all) of the exhaust gas of the combustor 3 that has fallen below the operating temperature of the fuel cell 1 is transferred to the air heat exchanger (second air preheater 6) via the cooler 7. Since the fuel cell cooling pipes 10a and 10b that flow are provided, the cooler 7 can be cooled by the exhaust of the combustor 3, which is a gas different from the power generation air, and directly affects the temperature of the power generation air. It is easy to adjust the temperature of the cooler 7 without receiving the heat.

  The operating temperature of the fuel cell 1 is about 800 ° C., and the temperature of the exhaust gas passing through the combustor 3 and the reformer 2 supplied to the cooler 7 is 700 ° C. Thus, the difference between the exhaust temperature (700 ° C.) of the combustor supplied to the cooler 7 and the operating temperature (800 ° C.) of the fuel cell 1 is within 300 ° C. According to this, since the temperature difference is suppressed within 300 ° C., no thermal shock is given to the cooling, so that the fuel cell power generator 100 with excellent durability can be obtained.

  Further, the reformer 2 serving as the fuel heat exchanger 2 is a preheater that preheats the fuel supplied to the fuel cell 1. According to this, the exhaust gas of the combustor 3 whose temperature has been lowered by heat exchange with the reformer 2 composed of a preheater can be supplied to the cooler 7.

  In addition, since the fuel heat exchanger 2 is also a reformer that reforms the fuel supplied to the fuel cell, the temperature of the exhaust gas from the combustor 3 supplied to the cooler 7 does not drop too much. Although all of the exhaust (secondary side) exhaust gas after passing through the reformer 2 is supplied into the cooler 7, a part of the exhaust gas may be supplied to the second air preheater 6 and the rest may be supplied to the cooler 7. good.

(Second Embodiment)
Next, a second embodiment of the present invention will be described. In the following embodiments, the same components as those in the first embodiment described above are denoted by the same reference numerals, description thereof will be omitted, and different configurations and features will be described.

  In FIG. 2, it has the exhaust air mixing valve 15 which comprises the air mixing means which mixes temperature-control air for temperature control with the exhaust_gas | exhaustion of the combustor 3 before being supplied to the cooler 7. In FIG. According to this, the temperature adjustment air is mixed with the exhaust of the combustor 3 before being supplied to the cooler 7 for temperature adjustment, so that the exhaust of the combustor 3 before being supplied to the cooler 7. The temperature of can be adjusted arbitrarily.

  In this case, the temperature adjustment air supplied by the single pipe is supplied to the air supply line and a part of the primary side fuel cell cooling pipe 10a by the exhaust air mixing valve 15, the air supply valve 16, and the air additional valve 14. Air can be supplied.

  Further, the exhaust gas after heat exchange by the heat exchanger 2 flows into the cooler 7 to cool the fuel cell 7. Then, the amount of air on the cathode side for cooling the fuel cell 7 is reduced. Incidentally, when the amount of air on the cathode side is increased and supplied to the cooler 7 to cool the fuel cell 7, the amount of air becomes enormous and the exhaust temperature of the fuel cell 1 and the combustor 3 decreases. Therefore, downsizing of the heat exchanger 2 can be achieved by the exhaust gas temperature increase accompanying the reduction of the air amount on the cathode side.

(Operational effect of the second embodiment)
In the said 2nd Embodiment, it has the exhaust air mixing valve 15 which mixes the temperature adjustment air for all or at least one part of the exhaust_gas | exhaustion of the combustor 3 before supplying to the cooler 7 for temperature control. Therefore, the temperature adjustment air is mixed with the exhaust gas of the combustor 3 before being supplied to the cooler 7 for temperature adjustment, so that the temperature of the exhaust gas of the combustor 3 before being supplied to the cooler 7 is adjusted. It can be adjusted arbitrarily.

(Third embodiment)
Next, a third embodiment of the present invention will be described. Features different from the above-described embodiment will be described. In FIG. 3, exhaust pressure feeding means for pumping the exhaust gas of the combustor 3 whose temperature is lower than the operating temperature of the fuel cell 1 by heat exchange with the reformer 2 serving as a heat exchanger for fuel to the cooler 7. A blower 17 is provided.

  According to this, the exhaust gas of the combustor 3 whose temperature is lower than the operating temperature of the fuel cell 1 due to heat exchange with the reformer 2 serving as a heat exchanger for fuel is passed through the exhaust pressure feeding means 17 made of, for example, a blower. Therefore, at least part of the exhaust gas from the combustor 3 can be reliably supplied to the cooler 7 without flowing back.

  In this case, the flow rate of the exhaust gas supplied to the cooler 7 can be controlled by controlling the flow rate of the blower constituting the exhaust pressure feeding means 17. According to this, for example, it is possible to adjust the cooling action of the cooler 7 by controlling the number of rotations of the blower motor and setting the flow rate of the blower 17 to a desired value.

  Moreover, you may discharge | release the exhaust gas which passed the 1st air preheater 5 in air | atmosphere through the hot water heater which becomes the waste heat utilization machine 18, for example. Reference numeral 21 denotes a first exhaust mixing pipe. In the outlet side pipe 21 of the reformer 2, the exhaust gas that has exited the reformer 2 and the exhaust gas that has passed through the cooler 7 are partially mixed. Then, the confused exhaust gas is re-pumped to the cooler 7 by the blower 17.

(Operational effect of the third embodiment)
Further, exhaust pressure feeding means 17 for pumping at least a part of the exhaust gas of the combustor 3 whose temperature is lower than the operating temperature of the fuel cell 1 by heat exchange with the fuel heat exchanger 2 to the cooler 7 is provided. According to this, at least a part of the exhaust gas of the combustor 3 whose temperature is lower than the operating temperature of the fuel cell 1 due to heat exchange with the fuel heat exchanger (reformer) 2 forms the exhaust pressure feeding means 17. For example, since pressure is supplied to the cooler 7 via a blower (or pump), at least a part of the exhaust gas of the combustor 3 can be reliably supplied to the cooler 7 without flowing back.

  Then, the flow rate of the exhaust pumping means 17 is controlled to control the flow rate of at least part of the exhaust gas supplied to the cooler 7. Therefore, the cooling action of the cooler 7 can be adjusted by controlling the flow rate by controlling, for example, the rotational speed of the blower motor constituting the exhaust pressure feeding means 17.

  Further, the exhaust gas of the combustor 3 whose temperature is lower than the operating temperature of the fuel cell 1 by heat exchange with the fuel heat exchanger 2 and the exhaust gas that has passed through the cooler 7 are mixed and then mixed. Exhaust pumping means 17 for pumping at least a part to the cooler 1 is provided.

  According to this, at least a part of the mixed exhaust gas after mixing the exhaust gas of the combustor 2 and the exhaust gas via the cooler 7 is transferred to the cooler 7 via the exhaust pressure feeding means 17 made of, for example, a blower. Since the gas is supplied, the temperature of the exhaust gas, which is the cooling gas supplied to the cooler 7, can be supplied at a temperature closer to the operating temperature of the fuel cell 1, and thermal shock can be reduced.

(Fourth embodiment)
Next, a fourth embodiment of the present invention will be described. Features different from the above-described embodiment will be described. In FIG. 4, the exhaust of the combustor 3 whose temperature is lower than the operating temperature of the fuel cell 1 due to heat exchange with the reformer 2 serving as a heat exchanger for fuel, the cooler 7, and the secondary fuel cell cooling pipe After the exhaust gas having passed through 10b is mixed, the downstream exhaust gas after mixing is supplied to the cooler 7 by a blower serving as the exhaust pressure feeding means 17.

  In this way, after the cooler passage exhaust gas from the secondary fuel cell cooling pipe 10b is mixed into the exhaust passage of the reformer 2 serving as a heat exchanger for fuel, the primary side fuel cell cooling pipe 10a is downstream. The mixed exhaust gas is supplied to the cooler 7 via the exhaust gas pressure feeding means 17.

  According to this, after mixing the exhaust gas of the combustor 3 and the exhaust gas for cooling that has passed through the cooler 7, at least a part of the mixed exhaust gas is passed through the exhaust pressure feeding means 17 on the downstream side. Therefore, compared with the third embodiment, the temperature of the exhaust gas serving as the cooling gas supplied to the cooler 7 can be further increased, and the temperature of the exhaust gas serving as the cooling gas supplied to the cooler 7 can be increased. It becomes possible to supply at a temperature close to the operating temperature of the fuel cell 1, and thermal shock can be reduced.

(Fifth embodiment)
Next, a fifth embodiment of the present invention will be described. Features different from the above-described embodiment will be described. In FIG. 5, the exhaust gas that has passed through the reformer 2 that is a heat exchanger for fuel and the exhaust gas that has been heat-exchanged with the second air preheater 6 that is another heat exchanger (downstream heat exchanger) are exhausted. It is discharged into the atmosphere via the tubes 22, 23 and 24. The exhaust pipes 22, 23, and 24 constitute exhaust exhaust means.

  The blower constituting the exhaust pressure feeding means 17 passes through the high-temperature exhaust gas that has passed through the reformer 2 serving as a fuel heat exchanger and the second air preheater 6 serving as another heat exchanger (downstream heat exchanger). The low-temperature exhaust gas thus supplied is supplied to the cooler 7 while being selectively sucked through a plurality of exhaust pressure feeding means side valves 26 and 27 arranged on the primary side of the blower 17. According to this, the temperature of the exhaust gas sucked by the blower 17 can be controlled by controlling the opening and closing of the exhaust pressure sending means side valves 26 and 27, so that the temperature of the exhaust gas supplied to the cooler 7 can be finely adjusted. .

(Operational effects of the fifth embodiment)
Exhaust discharge means 22 to 24 for exhausting the exhaust gas that has passed through the fuel heat exchanger 2 with the other heat exchanger (downstream heat exchanger) 6 and then discharging it into the atmosphere are provided. The high-temperature exhaust gas that has passed through the fuel heat exchanger 2 and the low-temperature exhaust gas that has passed through other heat exchangers (downstream heat exchangers) 6 are disposed on the exhaust pressure-feeding means 17 side. It is supplied to the cooler 7 while selectively sucking through means-side valves 26 and 27. According to this, the temperature of the exhaust gas sucked by the exhaust pressure feeding means 17 side can be controlled by controlling the exhaust pressure feeding means side valves 26 and 27, so that the temperature of the exhaust gas supplied to the cooler 7 can be adjusted.

(Sixth embodiment)
Next, a sixth embodiment of the present invention will be described. Features different from the above-described embodiment will be described. In FIG. 6, the exhaust gas that has passed through the cooler 7 has passed through the reformer 2 that serves as a fuel heat exchanger via a plurality of cooler-side valves 31 and 32 arranged on the secondary side of the cooler 7. The exhaust pipes 23 and 24 are inserted into the atmosphere after being selectively mixed with either the high-temperature exhaust gas or the low-temperature exhaust gas that has passed through the second air preheater 6 serving as another heat exchanger (downstream heat exchanger). Are discharged through.

  In this case, the exhaust pipe 22 includes the reformer 2 and the second air preheater 6 that serve as a heat exchanger for fuel via the cooler side valve 32 disposed on the cooler 7 side after the exhaust gas that has passed through the cooler 7. Becomes the second exhaust mixing pipe 22 through which the exhaust gas selectively mixed with the low-temperature exhaust gas passing through the series flows.

  Further, the exhaust gas selectively mixed through the plurality of cooler side valves 31 and 32 and passed through the other plurality of heat exchangers 6, 4 and 5 is blower side (exhaust pressure feeding means 17 side) valve 26, The air is supplied to the cooler 7 while being selectively sucked by the blower 17 through 27, 35, and 36. According to this, the temperature of the exhaust gas supplied to the cooler 7 can be controlled not only by the blower side valves 26, 27, 35, 36 but also by the cooler side valves 31, 32. Further, the temperature or flow rate of the exhaust gas flowing through the second air preheater 6, the fuel preheater 4, and the first air preheater 5 serving as other heat exchangers (downstream heat exchangers) is set to a plurality of cooler side valves 31. , 32 and the blower side valves 26, 27, 35, 36.

(Operational effects of the sixth embodiment)
In the sixth embodiment, the exhaust gas that has passed through the cooler 7 passes through the heat exchanger 2 for fuel via the plurality of cooler-side valves 31 and 32 disposed on the secondary side of the cooler 7. And the other low-temperature exhaust gas that has passed through the other heat exchanger (downstream heat exchanger) 6 are selectively mixed, and the selectively mixed exhaust gas is a plurality of exhaust-pressure-feeding-unit-side valves. The air is supplied to the cooler 7 while being selectively sucked by the exhaust pressure feeding means 17 through the nozzles 26 and 27.

  According to this, the temperature of the exhaust gas supplied to the cooler 7 can be controlled not only by the exhaust pressure feeding means side valves 26 and 27 but also by the cooler side valves 31 and 32. In addition, not only the high-temperature exhaust gas that has passed through the fuel heat exchanger 2 but also a part of the low-temperature exhaust gas that has passed through other heat exchangers (downstream heat exchangers) 6 and the like flow to the cooler 7, The temperature of the cooler 7 can be finely controlled by the exhaust pressure feeding means side valves 26 and 27 and the cooler side valves 31 and 32.

(Seventh embodiment)
Next, a seventh embodiment of the present invention will be described. Features different from the above-described embodiment will be described. In FIG. 7 which is the seventh embodiment, cooler side valves 37 and 38 are added as compared to FIG. As a result, the exhaust gas that has passed through the cooler 7 passes through the plurality of cooler-side valves 31, 32, 37, 38 disposed on the secondary side of the cooler 7, and the reformer 2 that serves as a fuel heat exchanger. The high-temperature exhaust gas that has passed through the second air preheater 6, the fuel preheater 4, and the low-temperature exhaust gas that has passed through the first air preheater 5 that serve as other heat exchangers (downstream heat exchangers). After being selectively mixed, it can be discharged to the atmosphere via the exhaust pipe 24.

  In this case, the exhaust pipe 22 selectively mixes the exhaust gas that has passed through the cooler 7 with the low-temperature exhaust gas that has passed through the second air preheater 6 via the cooler side valve 32. It becomes. Further, the exhaust pipes 23 and 24 serve as third and fourth exhaust mixing pipes, respectively.

  Further, the exhaust gas selectively mixed through the plurality of cooler side valves 31, 32, 37, 38 and passed through the other plurality of heat exchangers 6, 4, 5 is sent to the blower side valves 26, 27, The air is supplied to the cooler 7 while being selectively sucked by the blower 17 through 35 and 36. According to this, the temperature of the exhaust gas supplied to the cooler 7 can be finely controlled not only by the blower side valves 26, 27, 35, 36 but also by the cooler side valves 31, 32, 37, 38. Further, the temperature or flow rate of the exhaust gas flowing through the second air preheater 6, the fuel preheater 4, and the first air preheater 5 serving as other heat exchangers (downstream heat exchangers) is set to a plurality of cooler side valves 31, 32, 37, 38 and the exhaust pressure feeding means side valves 26, 27, 35, 36.

  According to the seventh embodiment, the exhaust gas after the heat exchange with the heat exchangers 2, 6, 4 and 5 is selectively introduced into the cooler 7 with the valves 26, 27, 35 and 36, and the fuel cell 7 is Cooling. Then, the amount of air on the cathode side for cooling the fuel cell 7 is reduced. Incidentally, when the amount of air on the cathode side is increased and supplied to the cooler 7 to cool the fuel cell 7, the amount of air becomes enormous and the exhaust temperature of the fuel cell 1 and the combustor 3 decreases. Therefore, the heat exchangers 2, 6, 4, and 5 can be downsized by reducing the amount of air on the cathode side and increasing the exhaust temperature.

  In addition, the temperature of the exhaust gas supplied to the cooler 7 can be controlled not only by the exhaust pressure sending means side valves 26, 27, 35, 36 but also by the cooler side valves 31, 32, 37, 38. In addition to the high-temperature exhaust gas that has passed through the fuel heat exchanger 2, a part of the low-temperature exhaust gas that has passed through other heat exchangers (downstream heat exchangers) 6, 4, and 5 is allowed to flow to the cooler 7. Thus, the temperature of the cooler 7 can be finely controlled by the exhaust pressure feeding means side valves 26, 27, 35, 36 and the cooler side valves 31, 32, 37, 38.

(Other embodiments)
The present invention is not limited to the above-described embodiments, and can be modified or expanded as follows. For example, in each of the above embodiments, a reformer is used, but when reforming is not required depending on the type of fuel, a fuel heat exchanger in which the fuel exchanges heat with exhaust gas or preheating for fuel is used instead of the reformer. Can be used.

2 Fuel heat exchanger (preheater, reformer)
6 Other heat exchangers (downstream heat exchangers)
5, 6 Heat exchanger for air 10a, 10b Fuel cell cooling piping 15 Exhaust air mixing valve 17 Exhaust pressure feeding means 22-24 Exhaust discharge means 26, 27, 35, 36 Plural valves 31, 32, 37 on the exhaust pressure feeding means side 38 Multiple cooler side valves

Claims (12)

A fuel cell (1) that operates with fuel and air supplied;
A cooler (7) for cooling the fuel cell (1);
A combustor (3) that is supplied with the fuel and air that has passed through the fuel cell (1) and burns;
A fuel heat exchanger (2) for heating the fuel before being supplied to the fuel cell (1) by the heat of the exhaust gas of the combustor (3);
At least a part of the exhaust gas of the combustor (3) that has fallen in temperature from the operating temperature of the fuel cell (1) due to heat exchange with the fuel heat exchanger (2) is transferred to the cooler (7). fuel cell cooling pipe (10a, 10b) to flow Bei give a,
Furthermore, it has an air heat exchanger (6) for heating the air before being supplied to the fuel cell (1) by the heat of the exhaust of the combustor (3),
At least a part of the exhaust of the combustor (3) that has fallen in temperature from the operating temperature of the fuel cell (1) due to heat exchange with the heat exchanger for fuel (2), the cooler (7) And a fuel cell cooling pipe (10b) flowing through the air heat exchanger (6) . And a plurality of cooler side valves (31, 32) arranged on the secondary side of the cooler (7),
The exhaust gas pressure-fed to the cooler (7) and passed through the cooler (7) passed through the fuel heat exchanger (2) via the plurality of cooler side valves (31, 32). 2. The fuel cell power generator according to claim 1, wherein the fuel cell power generator is selectively mixed with either the high-temperature exhaust gas and the low-temperature exhaust gas that has passed through the air heat exchanger (6) . 3. A fuel cell (1) that operates with fuel and air supplied;
A cooler (7) for cooling the fuel cell (1);
A combustor (3) that is supplied with the fuel and air that has passed through the fuel cell (1) and burns;
A fuel heat exchanger (2) for heating the fuel before being supplied to the fuel cell (1) by the heat of the exhaust gas of the combustor (3);
At least a part of the exhaust gas of the combustor (3) that has fallen in temperature from the operating temperature of the fuel cell (1) due to heat exchange with the fuel heat exchanger (2) is transferred to the cooler (7). A fuel cell cooling pipe (10a, 10b)
At least a part of the exhaust gas of the combustor (3) that has fallen in temperature from the operating temperature of the fuel cell (1) due to heat exchange with the fuel heat exchanger (2) is transferred to the cooler (7). fuel cell power generation system you further comprising a exhaust pressure feed means for pumping (17). Furthermore, it has an air heat exchanger (6) for heating the air before being supplied to the fuel cell (1) by the heat of the exhaust of the combustor (3),
At least a part of the exhaust of the combustor (3) that has fallen in temperature from the operating temperature of the fuel cell (1) due to heat exchange with the heat exchanger for fuel (2), the cooler (7) The fuel cell power generator according to claim 3 , further comprising a fuel cell cooling pipe (10 b) flowing through the air heat exchanger (6) . The fuel cell power generation according to claim 3 or 4 , wherein a flow rate of at least a part of the exhaust gas supplied to the cooler (7) is controlled by controlling a flow rate of the exhaust pressure feeding means (17). apparatus. The exhaust gas of the combustor (3), which has fallen in temperature from the operating temperature of the fuel cell (1) due to heat exchange with the heat exchanger for fuel (2), and pressure-fed to the cooler (7) it claims 3, characterized in that with the exhaust pressure feed unit cooler the exhaust and at least a portion of the mixture was mixed evacuated passing through (7) for pumping the cooler (7) (17) 5 The fuel cell power generator according to any one of the above. The fuel heat exchanger (2) and provided on the downstream side of the exhaust after the heat exchange, downstream the heat exchanger comprising an air heat exchanger for heat absorption (6) from the exhaust (6),
Exhaust discharge means (22-24) for discharging the exhaust heat absorbed by the downstream heat exchanger (6) into the atmosphere,
The exhaust pressure feeding means (17) converts the high temperature exhaust gas that has passed through the fuel heat exchanger (2) and the low temperature exhaust gas that has passed through the downstream heat exchanger (6) into the exhaust pressure feeding means ( it claims 3, characterized in that to be supplied to the cooler (7) while selectively sucked through 17) of a plurality arranged in a side exhaust pressure feed means side valve (26, 27) 6 either The fuel cell power generator according to one item. The exhaust gas pressure-fed to the cooler (7) and passed through the cooler (7) is passed through a plurality of cooler side valves (31, 32) arranged on the secondary side of the cooler (7). The high temperature exhaust gas that has passed through the fuel heat exchanger (2) and the low temperature exhaust gas that has passed through the downstream heat exchanger (6) are selectively mixed and mixed. The exhaust gas is supplied to the cooler (7) while being selectively sucked by the exhaust pressure feeding means (17) through the plurality of exhaust pressure feeding means side valves (26, 27). 8. The fuel cell power generator according to 7. An exhaust air mixing valve (15) for mixing temperature adjustment air for temperature adjustment to all or a part of the exhaust of the combustor (3) before being supplied to the cooler (7). Item 9. The fuel cell power generator according to any one of Items 1 and 3 to 8 . The cooler (7) the combustor is supplied to the (3) the temperature and the fuel cell (1) according to claim 1 to 9 in which the difference between the operating temperature may be equal to within 300 ° C. of the exhaust The fuel cell power generator according to any one of claims. The said heat exchanger (2) for fuels is a preheater (2) which preheats the said fuel supplied to the said fuel cell (1), It is any one of Claim 1 thru | or 10 characterized by the above-mentioned. Fuel cell power generator. The fuel heat exchanger (2) is any one of claims 1 to 10, wherein said a reformer that performs reforming of the fuel supplied to the fuel cell (1) (2) The fuel cell power generator described in 1.

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