JP5686519B2 - Fluid supply device and fuel cell system provided with fluid supply device - Google Patents

Description

  The present invention relates to a fluid supply device that increases the utilization efficiency of a pressure-increasing unit that boosts the fluid to be supplied as much as possible, and a fuel cell system including the fluid supply device.

  Conventionally, a fuel cell system has been developed as a cogeneration system. The fuel cell system is a power generation system that effectively uses exhaust heat when the fuel cell generates power. The fuel cell system includes a fluid supply device for supplying fluid to the fuel cell.

  FIG. 7 is a block diagram for explaining a fuel cell system including a conventional fluid supply apparatus. The fuel cell system A includes a fluid supply device B, a fuel cell module C, an inverter device D, and an exhaust heat recovery device E.

  The fluid supply device B supplies raw fuel and air to the fuel cell module C. The fluid supply device B takes in air from the outside air, removes impurities such as dust by the filter devices 11 and 31, and the air after removing the impurities is referred to as the blowers 12 and 32 (hereinafter referred to as “air blowers 12 and 32” in some cases). ) And the pressure is supplied to the fuel cell module C. Further, the fluid supply device B removes impurities from the raw fuel (city gas, natural gas, etc.) by the filter devices 21 and 41, and the raw fuel after the impurities are removed from the blowers 22 and 42 (hereinafter referred to as “fuel blower 22”). , 42 ")) and is supplied to the fuel cell module C.

  The fuel cell module C uses the raw fuel and air supplied from the fluid supply device B to generate electricity. The fuel cell module C generates hydrogen from the fuel cell C1 that generates power using a chemical reaction between hydrogen and oxygen, the raw fuel supplied from the fluid supply device B, and water supplied separately, and supplies the fuel cell C1 with hydrogen. A reformer C2 to be supplied and a burner C3 for heating the fuel cell C1 and the reformer C2 are provided. The raw fuel supplied from the fluid supply device B is supplied to the reformer C2 and the burner C3, and the air supplied from the fluid supply device B is supplied to the air electrode (cathode) and the burner C3 of the fuel cell C1. .

  Hydrogen is supplied from the reformer C2 to the fuel electrode (anode) of the fuel cell C1, and air is supplied from the fluid supply device B to the air electrode (cathode). The fuel cell C1 reacts hydrogen and oxygen in the air to generate electric energy and heat energy. The electrical energy extracted as DC power is output to the inverter device D. The generated thermal energy is recovered by the exhaust heat recovery device E. The reformer C2 generates hydrogen by a chemical reaction (steam reforming) between hydrocarbons (such as methane) contained in the raw fuel supplied from the fluid supply device B and water supplied separately. Heat is required for the chemical reaction. The fuel cell C1 has an operating temperature (for example, set in the range of 750 to 1000 ° C. in the case of a solid oxide fuel cell) depending on the material, and the fuel cell C1 is set to the operating temperature. Heat is also needed to maintain. The burner C3 burns raw fuel to heat the reformer C2 and the fuel cell C1 in order to cause a chemical reaction in the reformer C2 and to raise the temperature of the fuel cell C1 to the operating temperature. To do. Since the fuel cell C1 generates heat in its chemical reaction, the burner C3 is mainly used when the fuel cell system A is started.

  The inverter device D converts the DC power output from the fuel cell C1 into AC power and outputs the AC power. The inverter device D is linked to the power system, and the output AC power is supplied to the load. The exhaust heat recovery device E recovers heat generated by the fuel cell C1 and heat generated by combustion in the burner C3. The exhaust heat recovery device E uses the heat of the exhaust gas emitted from the fuel cell module C and uses it for hot water supply or the like.

  The fluid supply device B needs to stably supply the necessary fluid in order for the fuel cell module C to efficiently generate electric power. For example, as a method for controlling the fluid supply amount, a method using feedback control has been proposed. Japanese Patent Application Laid-Open No. 2004-95226 describes a fuel cell system that performs air flow control by feedback control when the detection value of an air flow sensor is in a normal range.

  Also in the fuel cell system A shown in FIG. 7, flow meters 13, 23, 33, 43 are provided downstream of the blowers 12, 22, 32, 42, and the flow rate of fluid is controlled by a control device (not shown). Feedback control. That is, the flow rate of the air supplied to the air electrode (cathode) of the fuel cell C1 is feedback controlled by adjusting the output of the air blower 12 so that the flow rate detected by the flow meter 13 matches the target flow rate. The The flow rate of the raw fuel supplied to the reformer C2 is feedback controlled by adjusting the output of the fuel blower 22 so that the flow rate detected by the flow meter 23 matches the target flow rate. The flow rate of the air supplied to the burner C3 is feedback-controlled by adjusting the output of the air blower 32 so that the flow rate detected by the flow meter 33 matches the target flow rate. The flow rate of the raw fuel supplied to the burner C3 is feedback-controlled by adjusting the output of the fuel blower 42 so that the flow rate detected by the flow meter 43 matches the target flow rate.

  In this case, the capacity of each of the blowers 12, 22, 32, and 42 needs to be selected assuming the maximum usage amount of the fluid supply destination. However, the case where the maximum amount of fluid is required is limited, and the blowers 12, 22, 32, and 42 are operated at a low load factor during normal rated operation. This reduces the utilization efficiency of each blower 12, 22, 32, 42 and causes an increase in power loss of the blower.

  In order to solve this problem, there has been proposed a method of providing a blower having a capacity corresponding to the flow rate used during normal rated operation and a blower additionally used when a flow rate exceeding this is required. Yes. For example, Japanese Patent Application Laid-Open No. 2008-248851 describes a flow control device that includes a plurality of small-capacity pumps and increases or decreases the number of operating pumps according to a required flow rate.

  FIG. 8 is a block diagram for explaining a fluid supply apparatus B 'incorporating this method. The fluid supply device B 'corresponds to the fluid supply device B in the fuel cell system A shown in FIG. In FIG. 8, the same or similar elements as those of the fluid supply device B are denoted by the same reference numerals. In FIG. 8, only elements for supplying air to the fuel cell C1 are shown, and elements for supplying air to the burner C3 and elements for supplying raw fuel are omitted. Yes.

  In the fluid supply device B ′, an air blower 12 ′ and a filter device 11 ′ are provided in parallel with the air blower 12 and the filter device 11. The check valve 6 is for preventing air sent from the air blower 12 from flowing into the blower 12 'side. The capacity of the air blower 12 is determined according to the flow rate during normal rated operation. Further, the capacity of the air blower 12 ′ is set to a capacity capable of supplying the maximum usage amount of the fluid supply destination (the air electrode of the fuel cell C 1) when combined with the capacity of the air blower 12. The control unit 5 performs feedback control using the flow rate detected by the flow meter 13 as a target flow rate. In addition, when the target flow rate is in a range that can be supplied by the air blower 12, the control unit 5 performs control by operating only the air blower 12 and adjusting the output of the air blower 12. On the other hand, when the target flow rate exceeds the range that can be supplied by the air blower 12, the output of the air blower 12 is maximized, the air blower 12 'is activated, and control is performed by adjusting the output of the air blower 12'.

  In the fluid supply device B ', since the air blower 12 having a capacity corresponding to this is used during normal rated operation, the use efficiency of the air blower 12 is not lowered, and wasteful power consumption can be reduced. When the target flow rate exceeds the capacity of the air blower 12, the air blower 12 'is also operated, so that air can be supplied up to the maximum usage amount of the supply destination.

JP 2004-95226 A JP 2008-248551 A

However, in this case, it is necessary to provide an air blower 12 ′ separately from the air blower 12 for normal rated operation. Further, it is necessary to separately provide a filter device 11 ′ for the air blower 12 ′, a check valve 6, and piping as a flow path for the air blower 12 ′. The fuel blower 22 not shown in FIG. 8 also requires a fuel blower connected in parallel, a filter device for the fuel blower, a check valve and piping. As a result, there is a problem that the fluid supply device B ′ is enlarged and the fuel cell system A as a whole is also enlarged. There is also a problem that the manufacturing cost increases due to an increase in the number of parts.

  The present invention has been conceived under the circumstances described above, and it is an object of the present invention to provide a fluid supply device that can increase the utilization efficiency of a blower as much as possible without providing a new blower separately. It is aimed.

  In order to solve the above problems, the present invention takes the following technical means.

The fluid supply device provided by the first aspect of the present invention is provided with a plurality of pipes that supply the same fluid to a plurality of supply destinations, and each of the pipes, and pressurizes and sends out the fluid. and blower, downstream from said blower, and a connection pipe for connecting the respective pipes, provided on at least one pipe of the plurality of pipes, and the outflow destination of the fluid flowing through the pipe the supply destination It is provided with the flow-path switching means switched with the said connection piping.

In a preferred embodiment of the present invention, the apparatus further comprises control means for controlling a flow rate downstream of the connection pipe in a pipe not provided with the flow path switching means, and the control means is a target value of the flow rate. Is less than a predetermined value, the flow path switching means is switched so that the flow destination of the fluid is the supply destination of the fluid in a pipe provided with the flow path switching means, and the target value of the flow rate is the predetermined value In the above case, the flow path switching means is switched so that the fluid outflow destination is the connection pipe.

In a preferred embodiment of the present invention, when the target value of the flow rate is less than the predetermined value, the control means adjusts the flow rate by adjusting an output of a blower provided in a pipe whose flow rate is controlled. When the target value of the flow rate is equal to or greater than the predetermined value, the flow rate is controlled by adjusting the output of a blower provided in a pipe provided with the flow path switching means.

In a preferred embodiment of the present invention, the flow path switching means can switch the flow destination of the fluid in multiple stages, and the control means has a flow rate target value equal to or greater than the predetermined value. In this case, the flow rate is controlled by adjusting switching of the fluid outflow destination by the flow path switching means until the flow path switching means is switched so that the fluid outflow destination is only the connection pipe. After switching the flow path switching means so that the fluid flows out only to the connection pipe, the flow rate is adjusted by adjusting the output of a blower provided in the pipe provided with the flow path switching means. Control.

  In a preferred embodiment of the present invention, the predetermined value is a first predetermined value that is used when the target value of the flow rate is increasing and a predetermined value that is used when the target value of the flow rate is decreasing. The second predetermined value is less than the first predetermined value.

  In a preferred embodiment of the present invention, the pipe for controlling the flow rate by the control means supplies air to the fuel cell, and the pipe provided with the flow path switching means supplies hydrogen supplied to the fuel cell. Air is supplied to a burner that heats at least one of the reformer to be produced and the fuel cell.

  In a preferred embodiment of the present invention, the pipe whose flow rate is controlled by the control means supplies gaseous fuel to a reformer that generates hydrogen to be supplied to the fuel cell, and the flow path switching means is provided. The pipe supplies the gaseous fuel to a burner that heats at least one of the reformer and the fuel cell.

  The fuel cell system provided by the second aspect of the present invention includes the fluid supply device provided by the first aspect of the present invention, the fuel cell, the reformer, and the burner. .

According to the present invention, a plurality of pipes blower is provided respectively, are connected to each other by a connecting pipe at the downstream side of the blower. Further, at least one pipe is provided with a flow path switching means for switching a fluid outflow destination. Accordingly, the flow rate switching means switches the flow destination of the fluid to the connection pipe, whereby the flow rate of the fluid supplied by the pipe not provided with the flow path switching means can be increased. Thereby, the pipe | tube in which the flow-path switching means is not provided can supply the fluid more than the capacity | capacitance of the blower provided in the said pipe | tube to a supply destination. Therefore, since the capacity of the blower can be set according to the flow rate supplied to the supply destination during rated operation, the utilization efficiency is not lowered and the power loss of the blower can be reduced.

Further, since a pipe provided for supplying a fluid to another supply destination and a blower provided in the pipe are used, it is not necessary to separately provide a new blower and a pipe. Therefore, compared with a case where a new blower and piping are separately provided, the fluid supply device and the system using the fluid supply device can be reduced in size, and the manufacturing cost can be suppressed.

  Other features and advantages of the present invention will become more apparent from the detailed description given below with reference to the accompanying drawings.

It is a block diagram for demonstrating 1st Embodiment of the fluid supply apparatus which concerns on this invention. It is a flowchart for demonstrating the flow control process of the air supplied to a fuel cell. It is a timing chart for demonstrating the flow control process of the air supplied to a fuel cell. It is a figure for demonstrating the effect at the time of setting a stop setting value separately from a starting setting value. It is a block diagram for demonstrating 2nd Embodiment of the fluid supply apparatus which concerns on this invention. It is a block diagram for demonstrating 3rd Embodiment of the fluid supply apparatus which concerns on this invention. It is a block diagram for demonstrating a fuel cell system provided with the conventional fluid supply apparatus. It is a block diagram for demonstrating another conventional fluid supply apparatus.

  Embodiments of the present invention will be specifically described below with reference to the accompanying drawings.

  FIG. 1 is a block diagram for explaining a first embodiment of a fluid supply apparatus according to the present invention. The fluid supply device B1 corresponds to the fluid supply device B in the fuel cell system shown in FIG. In FIG. 1, the same or similar elements as those of the fluid supply device B are denoted by the same reference numerals. Further, in FIG. 1, only elements for supplying air are shown, and elements for supplying raw fuel are not shown. Specifically, the filter devices 21 and 41, the fuel blowers 22 and 42, and the flow meters 23 and 43 in the fluid supply device B shown in FIG.

  The fluid supply device B1 supplies raw fuel and air to the fuel cell module C. In the present embodiment, a case where a solid oxide fuel cell is used as the fuel cell C1 will be described. The fluid supply device B1 includes filter devices 11 and 31, air blowers 12 and 32, flow meters 13 and 33, a control unit 5, a check valve 61, a three-way valve 62, and pipes 14, 34, and 63.

  The filter devices 11 and 31 remove impurities from the air taken from outside air. Filter elements 11 and 31 are each equipped with a filter element made of a material (for example, a polymer nonwoven fabric, a metal mesh, urethane, or the like) provided with a large number of holes having a diameter smaller than the impurity to be removed. . Impurities contained in the air are removed when passing through the filter element. If impurities adhere to the filter element and cause clogging, the power loss of the air blowers 12 and 32 on the downstream side will increase, resulting in a state in which the necessary flow rate cannot be supplied. Is done.

  The air blowers 12 and 32 increase the pressure of the air from which impurities have been removed by the filter devices 11 and 31 and send them out. Air sent from the air blower 12 flows through the pipe 14 and is supplied to the cathode side of the fuel cell C1, and air sent from the air blower 32 flows through the pipe 34 and is supplied to the burner C3 (see FIG. 7). The capacity | capacitance of the air blowers 12 and 32 is made into the capacity | capacitance according to the flow volume of the air used at the time of the normal rated driving | operation of the fuel cell C1 and the burner C3, respectively.

  Usually, at the start of starting the fuel cell system A, the burner C3 is used to raise the temperature of the fuel cell module C to a predetermined operating temperature (preset in a range of 750 to 1000 ° C.). Heating is performed (hereinafter, the process for raising the temperature is referred to as “temperature raising process”). Accordingly, the air blower 32 is in an operating state in order to supply air to the burner C3 in the temperature raising step. However, after the temperature raising step, when the fuel cell module C can maintain the operating temperature, the burner C3 stops heating, so the air blower 32 is stopped. Since the air needs to be supplied to the fuel cell C1 while the fuel cell system A is operating, the air blower 12 continues to operate.

The flow meters 13 and 33 measure the flow rate of the air flowing through the piping, and input the measured flow rate value to the control unit 5. The flow meter 13 measures the flow rate of air supplied to the fuel cell C1, and the flow meter 33 measures the flow rate of air supplied to the burner C3.

  The pipe 14 constitutes a flow path for supplying the air discharged from the air blower 12 to the fuel cell C1, and connects the discharge port of the air blower 12 and the suction port of the fuel cell C1. The pipe 34 constitutes a flow path for supplying the air discharged from the air blower 32 to the burner C3, and connects the discharge port of the air blower 32 and the suction port of the burner C3. The pipe 63 connects the pipe 14 and the pipe 34. The pipe 14 is connected to the pipe 63 between the air blower 12 and the flow meter 13, and the pipe 34 is connected to the pipe 63 via the three-way valve 62 between the air blower 32 and the flow meter 33. In addition, the discharge port of the filter apparatuses 11 and 31 and the suction port of the air blowers 12 and 32 are connected by piping, respectively.

  The check valve 61 is provided in the middle of the pipe 63 to prevent air from flowing out from the pipe 14 side to the pipe 34 side. As a result, the air discharged from the air blower 12 and flowing through the pipe 14 does not flow to the three-way valve 62 side, while the air discharged from the air blower 32 passes to the fuel cell C1 side via the three-way valve 62 and the pipe 63. Flowing.

  The three-way valve 62 is provided at a connection portion between the pipe 34 and the pipe 63 and switches the flow path of the air discharged from the air blower 32. Air discharged from the air blower 32 flows into the inlet of the three-way valve 62. The air discharged from one outlet of the three-way valve 62 flows through the pipe 34 as it is and is supplied to the burner C3. The air discharged from the other discharge port of the three-way valve 62 flows through the pipe 63 and the pipe 14 and is supplied to the fuel cell C1. That is, the three-way valve 62 can switch the supply destination of the air discharged from the air blower 32 between the fuel cell C1 and the burner C3. In the present embodiment, since the three-way valve 62 is, for example, an electric proportional control valve, the opening degree can be proportionally controlled. That is, the ratio of the air flow rate supplied to the fuel cell C1 and the burner C3 can be gradually changed. When the opening on the pipe 63 side is 0%, the opening on the pipe 34 side is 100%. When the opening on the pipe 63 side is gradually increased, the opening on the pipe 34 side gradually decreases. For example, if the opening on the pipe 63 side is 30%, the opening on the pipe 34 side is 70%, and 30% of the air discharged from the air blower 32 is supplied to the fuel cell C1, and 70% is supplied to the burner C3. Supplied.

  The control unit 5 controls the fluid supply device B1. The control unit 5 performs feedback control by adjusting the air blowers 12 and 32 and the three-way valve 62 so that the flow rate values input from the flow meters 13 and 33 coincide with the respective target flow rate values. The control unit 5 outputs an output control signal to the air blowers 12 and 32 to adjust the output of the air blowers 12 and 32, thereby controlling the flow rate of the air supplied to the fuel cell C1 or the burner C3. The control unit 5 also controls the flow rate of the air supplied to the fuel cell C1 by outputting an open / close control signal to the three-way valve 62 and adjusting the opening degree of the three-way valve 62 on the pipe 63 side.

  As described above, since heating by the burner C3 is required in the temperature raising process at the time of startup, it is necessary to supply air to the burner C3. Further, it is necessary to supply air to the fuel cell C1 while the fuel cell system A is in operation. Therefore, in the temperature rising process at the time of startup, the control unit 5 controls the flow rate of air supplied to the fuel cell C1 and the flow rate of air supplied to the burner C3, respectively, in order to independently control the flow rate of air supplied to the burner C3. Is set to 0% so that air does not flow from the pipe 34 through the pipe 63 to the pipe 14. The flow rate of air supplied to the fuel cell C1 is feedback-controlled by adjusting the air blower 12 based on the flow rate value input from the flow meter 13. Further, the flow rate of air supplied to the burner C3 is feedback controlled by adjusting the air blower 32 based on the flow rate value input from the flow meter 33.

  In the temperature raising process at the start-up, the fuel cell C1 is not in a state of supplying power to the inverter device D, and the fuel cell C1 is not generating electric power. Therefore, the fuel cell C1 is required only by the air blower 12. The air can be supplied.

  During normal operation after the temperature raising step, the fuel cell module C is in a state where it can maintain the operation temperature, so the burner C3 stops heating. Accordingly, the air blower 32 is stopped because it is not necessary to supply air to the burner C3. On the other hand, since the fuel cell system A is in an operating state and it is necessary to supply air to the fuel cell C1, the air blower 12 continues to operate.

During normal operation, the control unit 5 performs feedback control so that the flow rate value input from the flow meter 13 matches the given target flow rate value A ^* . The target flow rate value A ^* is set based on the air flow rate required by the fuel cell C1. The air flow rate required by the fuel cell C1 varies depending on the power required by the inverter device D and the like. For example, when the power taken out from the fuel cell C1 by the inverter device D increases, the fuel cell C1 needs more air, so the target flow rate value A ^* is increased. The control unit 5 is characterized in that the flow rate is controlled by changing the control method according to the target flow rate value A ^* . The control method will be described below with reference to FIG. 2 and FIG.

  FIG. 2 is a flowchart for explaining a flow rate control process of air supplied to the fuel cell C <b> 1 performed by the control unit 5. The flow rate control process is started when the fluid supply device B1 is activated, and is continued until the operation is stopped.

When the flow rate control process is started, it is determined whether or not the target flow rate value A ^* is smaller than the activation set value A ₀ (S1). The activation set value A ₀ is a flow rate threshold value for determining whether to activate the air blower 32, and the flow rate at the maximum output N1max of the air blower 12 is set in advance. When the target flow rate value A ^* is smaller than the starting set value A ₀ (S1: YES), the opening degree of the three-way valve 62 on the pipe 63 side is fully closed (0%), and the output of the air blower 12 is adjusted. Thus, the flow rate is controlled (S2), and the process returns to step S1. In the case of the temperature raising process at the time of startup, as described above, the air blower 32 is adjusted by the control unit 5 in a process different from the flow rate control process.

In step S1, if the target flow rate value A ^* is equal to or greater than the startup set value A ₀ (S1: NO), it is determined whether the target flow rate value A ^* is equal to the startup set value A ₀ (S3). When the target flow rate value A ^* is equal to the starting set value A ₀ (S3: YES), the output of the air blower 12 is fixed at the output when A ^* = A ₀ , that is, the maximum output N1max, and the air blower 32 is started or stopped. Then (S4), the process returns to step S1. When the air flow rate is increased and the target flow rate value A ^* increases and coincides with the activation set value A ₀ , the air blower 32 is activated, and the target flow rate value A ^* decreases while the air blower 32 is in operation. If the start set value A ₀ is reached, the air blower 32 is stopped. At this time, the opening degree of the three-way valve 62 on the pipe 63 side is fully closed (0%). The output of the activated air blower 32 becomes the minimum output N2min which is the lowest operable output.

In step S3, if the target flow rate value A ^* is not equal to the starting set value A ₀ (S3: NO), that is, if the target flow rate value A ^* is greater than the starting set value A ₀ , is the adjustment by the three-way valve 62 possible? It is determined whether or not (S5). When the target flow rate value A ^* increases, the output of the air blower 12 reaches the maximum output N1max, and the opening of the three-way valve 62 on the pipe 63 side does not reach the fully open state (100%). It is determined that adjustment by the three-way valve 62 is possible. On the other hand, when the target flow rate value A ^* decreases, the output of the air blower 32 reaches the minimum output N2min, and the opening degree of the three-way valve 62 on the pipe 63 side does not reach the fully closed state (0%). It is determined that the adjustment by the three-way valve 62 is possible. When the adjustment by the three-way valve 62 is possible (S5: YES), the output of the air blowers 12 and 32 is fixed, and the opening degree of the three-way valve 62 on the pipe 63 side is adjusted, thereby controlling the flow rate. (S6), it returns to step S1. On the other hand, when the adjustment by the three-way valve 62 is not possible (S5: NO), the output of the air blower 12 is fixed, and the output of the air blower 32 is adjusted to control the flow rate (S7), step S1. Return to.

FIG. 3 is a timing chart for explaining the flow rate control process, showing the target flow rate value A ^* , the output of the air blowers 12 and 32 and the opening degree of the three-way valve 62 on the pipe 63 side in accordance therewith. Yes. FIG. 6A shows the change in the target flow rate value A ^* . In the example shown in the figure, the target flow rate value A ^* increases from time t = t1 to t4, remains constant from time t = t4 to t5, and decreases from time t = t5 to t8. . FIGS. 4B and 4D show the outputs of the air blowers 12 and 32, and FIG. 2C shows the opening degree of the three-way valve 62 on the pipe 63 side.

From the time t = t1 to t2, since the target flow rate value A ^* is smaller than the start set value A _0, the flow control by output adjustment of the air blower 12 is performed (FIG. 2: see step S2). Therefore, only the output of the air blower 12 shown in FIG. Since the target flow rate value A ^* coincides with the starting set value A ₀ at time t = t2, the output of the air blower 12 is fixed at the maximum output N1max and the air blower 32 is started (FIG. 3 (d)). T = t2).

From the time t = t2 to t3, A ^*> is A _0, since the pipe 63 side of the opening of the three-way valve 62 is not yet fully opened (100%) (Fig. 2: YES in step S5), and the air blower 12 is fixed at the maximum output N1max, the output of the air blower 32 is fixed at the minimum output N2min, and the flow rate is controlled by adjusting the opening of the three-way valve 62 on the pipe 63 side (see FIG. 2: Step S6). . Therefore, only the opening degree on the pipe 63 side of the three-way valve 62 shown in FIG.

From the time t = t3 to t4, A ^*> is A _0, since the pipe 63 side of the opening of the three-way valve 62 is in the fully open state (FIG. 2: NO in step S5), and the output of the air blower 12 Is fixed at the maximum output N1max, and the flow rate is controlled by adjusting the output of the air blower 32 (see FIG. 2: Step S7). Therefore, only the output of the air blower 32 shown in FIG. From time t = t4 to t5, the flow rate is controlled by adjusting the output of the air blower 32 (see FIG. 2: step S7). However, since the target flow rate value A ^* does not change, the output of the air blower 32 is also changed. It has not changed. Of course, strictly speaking, feedback control is performed, so that the output of the air blower 32 is controlled by the control unit 5 so that the flow rate value input from the flow meter 13 becomes the target flow rate value A ^* .

From time t = t5 to t6, A ^* > A ₀ and the output of the air blower 32 has not reached the minimum output N2min. Therefore, the output of the air blower 12 is fixed at the maximum output N1max, and the output of the air blower 32 The flow rate is controlled by adjustment (see FIG. 2: Step S7). Therefore, only the output of the air blower 32 shown in FIG.

From time t = t6 to t7, A ^*> is A _0, the output is minimum output N2min air blower 32 and the pipe 63 side of the opening of the three-way valve 62 is fully closed (0%) Therefore, the output of the air blower 12 is fixed at the maximum output N1max, the output of the air blower 32 is fixed at the minimum output N2min, and the flow rate is controlled by adjusting the opening of the three-way valve 62 on the pipe 63 side ( (See FIG. 2: Step S6). Therefore, only the opening degree on the pipe 63 side of the three-way valve 62 shown in FIG.

At time t = t7, since the target flow rate value A ^* matches the start set value A _0, the air blower 32 is stopped (see t = t7 in FIG. 3 (d)). From time t = t7 to t8, the target flow rate value A ^* is smaller than the activation set value A ₀ , so the flow rate is controlled by adjusting the output of the air blower 12 (see FIG. 2: step S2). Therefore, only the output of the air blower 12 shown in FIG.

The flow rate control process shown in FIGS. 2 and 3 is an example, and the present invention is not limited to this. In the flow rate control process, the adjustment by the three-way valve 62 and the adjustment by the air blower 32 are separately performed, and only one of the adjustments is performed. However, both the adjustments are performed simultaneously to control the flow rate. Also good.

  Next, the operation of the fluid supply device B1 will be described.

  The fluid supply device B1 prevents the air from flowing from the pipe 34 through the pipe 63 to the pipe 14 by setting the opening degree on the pipe 63 side of the three-way valve 62 to 0% in the temperature raising process at the time of activation. The flow rate of air supplied to the fuel cell C1 is controlled by adjusting the air blower 12, and the flow rate of air supplied to the burner C3 is controlled by adjusting the air blower 32.

Further, during normal operation, since it is not necessary to supply air to the burner C3, the flow rate of air supplied to the fuel cell C1 is controlled by adjusting the air blowers 12, 32 and the three-way valve 62. That is, when the target flow rate value A ^* is smaller than the activation set value A ₀ , the fluid supply device B1 adjusts the output of the air blower 12 by setting the opening degree of the three-way valve 62 on the pipe 63 side to the fully closed state (0%). To control the flow rate. When the target flow rate value A ^* reaches the activation set value A ₀ , the air blower 32 is activated, the output of the air blowers 12 and 32 is fixed, and the opening on the pipe 63 side of the three-way valve 62 is adjusted to adjust the flow rate. Control. Further, after the target flow rate value A ^* increases and the opening degree of the three-way valve 62 on the pipe 63 side reaches the fully open state (100%), the flow rate is controlled by adjusting the output of the air blower 32.

When the target flow rate value A ^* decreases, first, the flow rate is controlled by adjusting the output of the air blower 32. When the output of the air blower 32 reaches the minimum output N2min, the flow rate is controlled by adjusting the opening degree of the three-way valve 62 on the pipe 63 side. Further, after the target flow rate value A ^* is lowered and the opening of the three-way valve 62 on the pipe 63 side reaches the fully closed state (0%), the flow rate is controlled by adjusting the output of the air blower 12.

  Next, the operation of the fluid supply device B1 will be described.

When the target flow rate value A ^* is larger than the activation set value A ₀ , the fluid supply device B1 can control the flow rate by adjusting the output of the air blower 32 and the opening of the three-way valve 62. Further, the air can be supplied to the fuel cell C <b> 1 up to the combined capacity of the air blower 12 and the air blower 32. Therefore, since the capacity of the air blower 12 can be set to a capacity corresponding to the flow rate of air used during normal rated operation of the fuel cell C1, the utilization efficiency does not decrease and the power loss of the blower can be reduced.

In addition, the fluid supply device B1 uses an air blower 32 provided to supply air to the burner C3 to supply air to the fuel cell C1. Therefore, it is not necessary to separately provide a new air blower for the case where air exceeding the capacity of the air blower 12 is required. Further, it is not necessary to add a filter device and piping for the new air blower. Therefore, compared with the case where a new air blower is provided separately, the fluid supply device B1 and the fuel cell system A using the same can be reduced in size, and the manufacturing cost of the device can be suppressed.

In the first embodiment, when the target flow rate value A ^* coincides with the starting set value A ₀ , the discharge of the three-way valve 62 is switched to the pipe 63 side (the opening degree on the pipe 63 side is fully opened (100 %)), The flow control is not performed by adjusting the output of the air blower 32 for the following reason. That is, discharge the moment of switching on the pipe 63 side of the three-way valve 62, so that the supply of air by the minimum output N2min air blower 32 is added. When the flow rate of supplied air rapidly increases, the temperature of the fuel cell C1 rapidly decreases. The fuel cell C1 has an operating temperature (for example, set in the range of 750 to 1000 ° C. in the case of a solid oxide fuel cell) depending on the material, and the temperature suddenly drops below the operating temperature. Then, the fuel cell C1 may be damaged. Therefore, in order to avoid a sudden change in the flow rate of the air supplied to the fuel cell C1, the opening degree of the three-way valve 62 on the pipe 63 side is gradually changed.

Therefore, if the fuel cell C1 can cope with a rapid temperature change, or if the minimum output N2min of the air blower 32 is small (when the flow rate of air supplied to the fuel cell C1 does not change suddenly), the target When the flow rate value A ^* matches the activation set value A ₀ , the discharge of the three-way valve 62 may be switched to the pipe 63 side, and thereafter the flow rate control may be performed by adjusting the output of the air blower 32. In this case, the three-way valve 62 need not be an electric proportional control valve, and can be, for example, an electromagnetic valve.

In the first embodiment, the starting set value A ₀ is the flow rate at the maximum output N1max of the air blower 12. However, the present invention is not limited to this. The activation set value A ₀ may be a value equal to or less than the flow rate at the maximum output N1max of the air blower 12.

In the first embodiment, the activation set value A ₀ is used as the threshold value regardless of whether the target flow rate value A ^* increases or decreases. However, the present invention is not limited to this. A stop set value A ₁ , which is smaller than the start set value A _0, may be set separately and used as a threshold value when the target flow rate value A ^* decreases. In this case, it is possible to target flow rate value A ^* to suppress the repetition (so-called hunting phenomenon) Starting and stopping the air blower 32 by changing the startup set value A ₀ before and after.

FIG. 4 is a diagram for explaining the effect when the stop set value A ₁ is set separately from the start set value A ₀ . The solid line shown in the figure shows the change in the target flow rate value A ^* . Whether the target flow rate value A ^* increases or decreases, when the activation set value A ₀ is used as a threshold value, the air blower 32 is activated at time t = ta, tc, te, and at time t = tb, td, tf. The air blower 32 is stopped. On the other hand, when the threshold value when the target flow rate value A ^* is lowered is set to the stop set value A ₁ , the air blower 32 is started at time t = ta and the air blower 32 is stopped at time t = tg. Therefore, the start and stop of the air blower 32 at time t = tb to tf can be suppressed. Thereby, deterioration of the motor built in the air blower 32 by the repetition of starting and stopping can be suppressed.

  Note that two control valves may be used instead of the three-way valve 62, and the opening degree of the other control valve may be changed according to the opening degree of the one control valve. That is, when the opening of one control valve is 100%, the opening of the other control valve is 0%, and when the opening of one control valve is 0%, the opening of the other control valve is 100%. You may make it adjust so.

  In the first embodiment, the case where the control unit 5 performs feedback control has been described. However, the present invention is not limited to this. For example, the present invention can be applied to other control such as feedforward control.

  In the first embodiment, the case where the present invention is applied to the flow path for supplying air to the fuel cell module C (see FIG. 7) has been described. However, the flow path for supplying raw fuel to the fuel cell module C. Also, the present invention can be applied. Hereinafter, a fluid supply apparatus to which the present invention is applied to a flow path for supplying raw fuel will be described as a second embodiment.

  FIG. 5 is a block diagram for explaining a second embodiment of the fluid supply apparatus according to the present invention. The fluid supply device B2 corresponds to the fluid supply device B in the fuel cell system shown in FIG. In FIG. 5, the same or similar elements as those of the fluid supply device B are denoted by the same reference numerals. Further, only elements for supplying raw fuel are described, and elements for supplying air are omitted. Specifically, the description of the filter devices 11 and 31, the air blowers 12 and 32, and the flow meters 13 and 33 in the fluid supply device B shown in FIG. 7 is omitted.

  The fluid supply device B2 supplies raw fuel and air to the fuel cell module C. The fluid supply device B2 includes filter devices 21 and 41, fuel blowers 22 and 42, flow meters 23 and 43, a control unit 5, a check valve 71, a three-way valve 72, and pipes 24, 44, and 73.

  The filter devices 21 and 41 remove impurities from the raw fuel. Each of the filter devices 21 and 41 includes a filter element made of a material (for example, a metal mesh, a polymer nonwoven fabric, urethane, or the like) provided with a large number of holes having a diameter smaller than the impurity to be removed. . Impurities contained in the raw fuel are removed when passing through the filter element.

  The fuel blowers 22 and 42 pressurize and send out the raw fuel from which impurities are removed by the filter devices 21 and 41. The raw fuel delivered by the fuel blower 22 flows through the pipe 24 and is supplied to the reformer C2, and the raw fuel delivered by the fuel blower 42 flows through the pipe 44 and is supplied to the burner C3 (see FIG. 7). The capacity | capacitance of the air blowers 22 and 42 is set as the capacity | capacitance according to the flow volume of the raw fuel used at the time of the normal rated driving | operation of the reformer C2 and the burner C3, respectively.

As described above, since the burner C3 performs heating in the temperature raising step, the fuel blower 42 is in an operating state in order to supply raw fuel to the burner C3. Further, after the temperature raising step, the burner C3 stops heating, so the fuel blower 42 is stopped. Since it is necessary to supply hydrogen to the fuel cell C1 while the fuel cell system A is in operation, it is necessary to supply raw fuel to the reformer C2. Accordingly, the fuel blower 22 continues to operate.

  The flow meters 23 and 43 measure the flow rate of the raw fuel flowing through the pipe, and input the measured flow rate value to the control unit 5. The flow meter 23 measures the flow rate of the raw fuel supplied to the reformer C2, and the flow meter 43 measures the flow rate of the raw fuel supplied to the burner C3.

  The pipe 24 constitutes a flow path for supplying the raw fuel discharged from the fuel blower 22 to the reformer C2, and connects the discharge port of the fuel blower 22 and the suction port of the reformer C2. ing. The pipe 44 constitutes a flow path for supplying the raw fuel discharged from the fuel blower 42 to the burner C3, and connects the discharge port of the fuel blower 42 and the suction port of the burner C3. The pipe 73 connects the pipe 24 and the pipe 44. The pipe 24 is connected to the pipe 73 between the fuel blower 22 and the flow meter 23, and the pipe 44 is connected to the pipe 73 via the three-way valve 72 between the fuel blower 42 and the flow meter 43. The discharge ports of the filter devices 21 and 41 and the suction ports of the fuel blowers 22 and 42 are connected by piping.

  The check valve 71 is provided in the middle of the pipe 73 so as to prevent the raw fuel from flowing out from the pipe 24 side to the pipe 44 side. Thereby, the raw fuel discharged from the fuel blower 22 and flowing through the pipe 24 does not flow to the three-way valve 72 side, while the raw fuel discharged from the fuel blower 42 is reformed via the three-way valve 72 and the pipe 73. It flows to the C2 side.

The three-way valve 72 is provided at a connection portion between the pipe 44 and the pipe 73 and switches the flow path of the raw fuel discharged from the fuel blower 42. The raw fuel discharged from the fuel blower 42 flows into the inlet of the three-way valve 72. The raw fuel discharged from one discharge port of the three-way valve 72 flows as it is through the pipe 44 and is supplied to the burner C3. The raw fuel discharged from the other discharge port of the three-way valve 72 flows through the pipe 73 and the pipe 24 and is supplied to the reformer C2. That is, the three-way valve 72 can switch the supply destination of the raw fuel discharged from the fuel blower 42 between the reformer C2 and the burner C3. In the present embodiment, since the three-way valve 72 is, for example, an electric proportional control valve, the opening degree can be proportionally controlled. That is, the ratio of the raw fuel flow rate supplied to the reformer C2 and the burner C3 can be gradually changed. When the opening on the pipe 73 side is 0%, the opening on the pipe 44 side is 100%. When the opening on the pipe 73 side is gradually increased, the opening on the pipe 44 side is gradually reduced. For example, if the opening degree on the pipe 73 side is 30%, the opening degree on the pipe 44 side is 70%, and 30% of the raw fuel discharged from the fuel blower 42 is supplied to the reformer C2, and 70% is burner. Supplied to C3.

The control unit 5 controls the fluid supply device B2 . The control unit 5 performs feedback control by adjusting the fuel blowers 22 and 42 and the three-way valve 72 so that the flow rate values input from the flow meters 23 and 43 coincide with the respective target flow rate values. The controller 5 controls the flow rate of the raw fuel supplied to the reformer C2 or the burner C3 by outputting output control signals to the fuel blowers 22 and 42 and adjusting the outputs of the fuel blowers 22 and 42. . The control unit 5 also controls the flow rate of the raw fuel supplied to the reformer C2 by outputting an open / close control signal to the three-way valve 72 and adjusting the opening degree of the three-way valve 72 on the pipe 73 side.

  As described above, since heating by the burner C3 is necessary in the temperature raising process at the time of startup, it is necessary to supply raw fuel to the burner C3. Further, it is necessary to supply raw fuel to the reformer C2 while the fuel cell system A is in operation. Therefore, in the temperature raising process at the start-up, the control unit 5 controls the three-way valve 72 to independently control the flow rate of the raw fuel supplied to the reformer C2 and the flow rate of the raw fuel supplied to the burner C3. The opening degree on the pipe 73 side is set to 0% so that the raw fuel does not flow from the pipe 44 through the pipe 73 to the pipe 24. Then, the flow rate of the raw fuel supplied to the reformer C2 is feedback controlled by adjusting the fuel blower 22 based on the flow rate value input from the flow meter 23. Further, the flow rate of fuel supplied to the burner C3 is feedback controlled by adjusting the air blower 42 based on the flow rate value input from the flow meter 43.

  In the temperature raising process at the time of startup, the reformer C2 is not in a state of supplying power to the inverter device D, and the fuel cell C1 is not generating power. Can supply the fuel needed.

  During normal operation after the temperature raising step, the fuel cell module C is in a state where it can maintain the operation temperature, so the burner C3 stops heating. Therefore, the fuel blower 42 is stopped because it is not necessary to supply raw fuel to the burner C3. On the other hand, since the fuel cell system A is in operation and it is necessary to supply raw fuel to the reformer C2, the fuel blower 22 continues to operate.

  During normal operation, the control unit 5 performs feedback control so that the flow rate value input from the flow meter 23 matches the given target flow rate value. The target flow rate value is set based on the raw fuel flow rate required by the reformer C2. The flow rate of the raw fuel required by the reformer C2 varies depending on the power required by the inverter device D. For example, when the electric power that the inverter device D extracts from the fuel cell C1 increases, the target flow rate value is increased because the fuel cell C1 requires more raw fuel. The control unit 5 is characterized in that the flow rate is controlled by changing the control method according to the target flow rate value. The flow control process of the raw fuel supplied to the reformer C2 is the same process as the flow control process in the first embodiment.

  The fluid supply device B2 prevents the raw fuel from flowing from the pipe 44 through the pipe 73 to the pipe 24 by setting the opening degree of the three-way valve 72 on the pipe 73 side to 0% in the temperature raising process at the time of activation. Then, the flow rate of the raw fuel supplied to the reformer C2 is controlled by adjusting the fuel blower 22, and the flow rate of the raw fuel supplied to the burner C3 is controlled by adjusting the fuel blower 42.

  Further, since it is not necessary to supply raw fuel to the burner C3 during normal operation, the flow rate of the raw fuel supplied to the reformer C2 is controlled by adjusting the fuel blowers 22 and 42 and the three-way valve 72. To do. That is, when the target flow rate value is smaller than the starting set value, the fluid supply device B2 sets the opening degree of the three-way valve 72 on the pipe 73 side to the fully closed state (0%) and adjusts the output of the fuel blower 22 to adjust the flow rate. To control. When the target flow rate value reaches the startup set value, the fuel blower 42 is started, the output of the fuel blowers 22 and 42 is fixed, and the opening degree on the pipe 73 side of the three-way valve 72 is adjusted to control the flow rate. Further, after the target flow rate value increases and the opening degree of the three-way valve 72 on the pipe 73 side reaches the fully open state (100%), the flow rate is controlled by adjusting the output of the fuel blower 42.

  When the target flow rate value decreases, first, the flow rate is controlled by adjusting the output of the fuel blower 42. When the output of the fuel blower 42 reaches the minimum output, the flow rate is controlled by adjusting the opening degree of the three-way valve 72 on the pipe 73 side. After the target flow rate value further decreases and the opening degree of the three-way valve 72 on the pipe 73 side reaches the fully closed state (0%), the flow rate is controlled by adjusting the output of the fuel blower 22.

  When the target flow rate value is larger than the activation set value, the fluid supply device B2 can control the flow rate by adjusting the output of the fuel blower 42 and the opening of the three-way valve 72. In addition, the raw fuel can be supplied to the reformer C2 up to the total capacity of the fuel blower 22 and the fuel blower 42. Therefore, since the capacity of the fuel blower 22 can be set to a capacity corresponding to the flow rate of the raw fuel used during the normal rated operation of the reformer C2, the utilization efficiency is not lowered and the power loss of the blower can be reduced. .

The fluid supply device B2 also uses the fuel blower 42 provided for supplying raw fuel to the burner C3 to supply raw fuel to the reformer C2. Therefore, it is not necessary to separately provide a new fuel blower for a case where raw fuel exceeding the capacity of the fuel blower 22 is required. Further, it is not necessary to add a filter device and piping for the new fuel blower. Therefore, compared with the case where a new fuel blower is separately provided, the fluid supply device B2 and the fuel cell system A using the same can be reduced in size, and the manufacturing cost can be suppressed.

Also in the second embodiment, when the fuel cell C1 can cope with a rapid temperature change, or when the minimum output of the fuel blower 42 is small (the flow rate of the raw fuel supplied to the reformer C2 changes suddenly). If not, the discharge of the three-way valve 72 may be switched to the pipe 73 side when the target flow rate value matches the activation set value, and thereafter the flow rate control may be performed by adjusting the output of the fuel blower 42. . Further, the activation set value may be a value equal to or less than the flow rate at the maximum output of the fuel blower 22. Alternatively, a stop set value that is smaller than the start set value may be set separately and used as a threshold when the target flow rate value decreases. Two control valves may be used instead of the three-way valve 72, and the control in the control unit 5 may be other control such as feedforward control.

  FIG. 6 is a block diagram for explaining a third embodiment of the fluid supply apparatus according to the present invention. The fluid supply device B3 shown in the figure includes a flow path for supplying air of the fluid supply device B1 (see FIG. 1) shown in the first embodiment and a fluid supply device B2 (see FIG. 5) shown in the second embodiment. A flow path for supplying raw fuel is shown in combination. Since each element of the fluid supply device B3 is the same as each element of the fluid supply device B1 and the fluid supply device B2, description thereof will be omitted.

  In the first to third embodiments, the fuel cell C1 is a solid oxide fuel cell. However, the present invention is not limited to this. The present invention is also applicable to the case where air or raw fuel is supplied to a fuel cell module that uses other types of fuel cells such as molten carbonate fuel cells, polymer electrolyte fuel cells, and phosphoric acid fuel cells. Can do.

In the first to third embodiments, a flow path for supplying air to the fuel cell C1 (flow path including the filter device 11, the air blower 12, and the pipe 14), and a flow path for supplying air to the burner C3. (Flow path consisting of filter device 31, air blower 32, and pipe 34), flow path for supplying raw fuel to reformer C2 (flow path consisting of filter device 21, fuel blower 22, and pipe 24), burner C3 In the above description, the number of the flow paths for supplying the raw fuel (the flow path including the filter device 41, the fuel blower 42, and the pipe 44) is one, but the present invention is not limited to this. There may be a configuration in which there are a plurality of any of them.

  In the first to third embodiments, the case where the fluid supply apparatus according to the present invention is used in a fuel cell system has been described. However, the present invention is not limited to this. The present invention can also be applied to a fluid supply apparatus that supplies fluid to other systems. The supplied fluid is not limited to air and raw fuel, but may be other gas or liquid. For example, the fluid supply apparatus according to the present invention can be used for a system that needs to continuously supply cooling water.

  The fluid supply apparatus according to the present invention is not limited to the above-described embodiment. The specific configuration of each part of the fluid supply apparatus according to the present invention can be varied in design in various ways.

A Fuel cell system B, B1, B2, B3 Fluid supply device 11, 21, 31, 41 Filter device 12, 32 Air blower 22, 42 Fuel blower 13, 23, 33, 43 Flow meter 5 Control unit 61, 71 Check Valve 62, 72 Three-way valve C Fuel cell module C1 Fuel cell C2 Reformer C3 Burner D Inverter device E Waste heat recovery device

Claims (8)

A plurality of pipes for supplying the same fluid to a plurality of supply destinations;
A blower provided to each of the pipes for boosting and feeding the fluid;
On the downstream side of the blower , connecting pipes for connecting the pipes;
A flow path switching unit that is provided in at least one of the plurality of pipes, and switches an outflow destination of the fluid flowing through the pipes between the supply destination and the connection pipe;
A fluid supply device comprising: In the pipe not provided with the flow path switching means, further comprising a control means for controlling the flow rate downstream from the connection pipe,
When the target value of the flow rate is less than a predetermined value, the control means switches the flow path switching means so that the fluid outflow destination is the fluid supply destination in a pipe provided with the flow path switching means. When the target value of the flow rate is equal to or greater than the predetermined value, the flow path switching unit is switched so that the outflow destination of the fluid is the connection pipe.
The fluid supply apparatus according to claim 1. When the target value of the flow rate is less than the predetermined value, the control means controls the flow rate by adjusting an output of a blower provided in a pipe whose flow rate is controlled, and the target value of the flow rate is The fluid supply device according to claim 2, wherein the flow rate is controlled by adjusting an output of a blower provided in a pipe provided with the flow path switching unit when the flow rate is equal to or greater than a predetermined value. The flow path switching means can switch the flow destination of the fluid in multiple stages,
When the target value of the flow rate is equal to or greater than the predetermined value, the control means is configured to switch the fluid flow by the flow path switching means until the flow path switching means is switched so that the flow destination of the fluid is only the connection pipe. The flow rate is controlled by adjusting switching of the flow destination of the fluid, and the flow channel switching means is provided after the flow channel switching means is switched so that the fluid flow destination is only the connection pipe. The fluid supply apparatus according to claim 3, wherein the flow rate is controlled by adjusting an output of a blower provided in a pipe.   The predetermined value includes a first predetermined value used when the target value of the flow rate is increasing and a second predetermined value used when the target value of the flow rate is decreasing, The fluid supply device according to any one of claims 2 to 4, wherein the second predetermined value is less than the first predetermined value. The pipe whose control means controls the flow rate supplies air to the fuel cell,
The pipe provided with the flow path switching unit supplies air to a burner that heats at least one of the reformer that generates hydrogen to be supplied to the fuel cell and the fuel cell.
The fluid supply apparatus according to any one of claims 2 to 5. The pipe whose control means controls the flow rate supplies gaseous fuel to a reformer that generates hydrogen to be supplied to the fuel cell,
The pipe provided with the flow path switching means supplies the gaseous fuel to a burner that heats at least one of the reformer and the fuel cell.
The fluid supply apparatus according to any one of claims 2 to 5. A fluid supply device according to claim 6 or 7,
The fuel cell, the reformer, and the burner;
A fuel cell system comprising:

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