JP6590271B2 - Fuel cell system - Google Patents

Description

  The present invention relates to a fuel cell system.

  Fuel cells are used as power generation units in distributed power generation systems because they can increase power generation efficiency even on a small scale.

  In order to function as a distributed power generation system, it is necessary to stably supply raw materials during power generation. Generally, natural gas (city gas) mainly composed of natural gas supplied from an existing infrastructure, LPG, gasoline, kerosene, or the like is used as a raw material. The reformed gas obtained by reforming such a raw material becomes a fuel for the fuel cell, and the raw material contains a sulfur compound.

  For example, an odorant for detecting leakage from infrastructure such as dimethyl sulfide and tertiary methyl mercaptan by smell is an example.

  Such a sulfur compound in the raw material becomes a poisoning component of the catalyst used in the reformer for reforming the raw material, and decreases the reactivity.

  Therefore, a desulfurizer for removing sulfur compounds in the raw material is additionally provided. Examples of such a desulfurizer include an adsorption desulfurizer that adsorbs and removes sulfur compounds and a hydrogenated desulfurizer that hydrogenates (hydrogenates) sulfur compounds and removes them.

  Since the hydrodesulfurizer has a high removal rate of sulfur compounds, the desulfurizer can be reduced in size, but it is necessary to stably add hydrogen to the raw material gas. For hydrogen, a part of the reformed gas obtained by reforming the raw material is used, and the reformed gas is recycled to the raw material.

  When the reformed gas is recycled, hydrogen may not be stably added to the raw material when the recycling path is clogged with condensed water from water vapor in the reformed gas. Therefore, a fuel system has been proposed that includes a water vapor condensing separator for removing water vapor in the reformed gas in the recycle path (see, for example, Patent Document 1).

  In order to supply more than a certain amount of hydrogen, it is equipped with a pressure detector that detects the pressure in the source gas supply path upstream from the junction with the recycle path, and a flow rate controller that is provided in the recycle path. In view of the detection value of the gas detector, a configuration is proposed in which the flow rate controller is controlled so that the volume ratio of the hydrogen-containing gas added to the raw material gas via the recycling path is equal to or higher than the lower limit (for example, a patent) Reference 2).

JP 2002-356308 A JP 2012-250876 A

  However, in the conventional example, when an appropriate amount of recycle gas necessary for the hydrodesulfurization reaction is supplied to the raw material, adequate control of the flow rate of the raw material containing the recycle gas has not been sufficiently studied.

  An aspect of the present invention has been made in view of such circumstances, and when supplying an appropriate amount of recycle gas necessary for hydrodesulfurization reaction to a raw material, it contains a recycle gas as compared with the conventional case. A fuel cell system capable of appropriately controlling a raw material flow rate is provided.

  In order to solve the above problems, a fuel cell system according to an aspect of the present invention includes a fuel cell, a hydrodesulfurizer that removes sulfur components in the raw material, and a raw material from the hydrodesulfurizer. A reformer that generates reformed gas to be supplied to the fuel cell, a raw material path through which the raw material to be supplied to the hydrodesulfurizer flows, and a constant volume type raw material supplier that supplies the raw material to the hydrodesulfurizer A recycle path for supplying a part of the reformed gas from the reformer as a recycle gas to a raw material flowing through the raw material path upstream of the raw material supplier, and a recycle gas from the recycle path A raw material flow rate measuring device that measures the flow rate of the raw material flowing through the raw material path upstream from the inflowing junction, a raw material flow rate adjuster that adjusts the flow rate of the raw material passing through the raw material flow rate measuring device, and the raw material supply device Discharge flow rate and the above Flow rate difference between the material flow rate measured by mass flow instrument, so that the difference amount set in advance, and a controller for controlling the raw material flow regulator, and the raw material supplier.

  The fuel cell system of one embodiment of the present invention can appropriately control the flow rate of the raw material containing the recycle gas when supplying an appropriate amount of the recycle gas necessary for the hydrodesulfurization reaction to the raw material as compared with the conventional case.

FIG. 1 is a diagram illustrating an example of a fuel cell system according to the first embodiment. FIG. 2 is a flowchart showing an example of the operation of the fuel cell system of the first embodiment. FIG. 3 is a diagram illustrating an example of a fuel cell system according to Example 1 of the first embodiment. FIG. 4 is a diagram illustrating an example of a fuel cell system according to Example 2 of the first embodiment. FIG. 5 is a diagram illustrating an example of a fuel cell system according to the second embodiment. FIG. 6 is a flowchart showing an example of the operation of the fuel cell system of the second embodiment. FIG. 7 is a diagram illustrating an example of a fuel cell system according to Example 1 of the second embodiment. FIG. 8 is a diagram illustrating an example of a fuel cell system according to Example 2 of the second embodiment.

(Embodiment 1)
The inventors diligently studied the appropriate control of the flow rate of the raw material containing recycle gas when supplying an appropriate amount of recycle gas necessary for the hydrodesulfurization reaction to the raw material, and obtained the following knowledge.

  For stable operation of the fuel cell, stable generation of reformed gas is important. For stable generation of reformed gas, hydrogen (reformed gas) is added to the raw material within a certain range (recycling) in order to ensure the performance of the hydrodesulfurizer that prevents sulfur poisoning of the reforming catalyst. )There is a need to. In addition, the flow rate of the recycled gas-containing raw material sent to the reformer affects the heat balance and steam carbon ratio in the reforming reaction. Therefore, it is necessary to suppress variations in the amount of gas supplied to the reformer. In particular, when a part of the reformed gas is recycled to the raw material, it is often difficult to balance the flow rate of the raw material containing the recycled gas. Therefore, the inventors have determined that such a raw material supply system still has room for improvement.

  Therefore, the fuel cell system of this embodiment includes a fuel cell, a hydrodesulfurizer that removes sulfur components in the raw material, and a reformed gas for supplying the fuel cell using the raw material from the hydrodesulfurizer. A reformer that generates a hydrogen, a raw material path through which a raw material to be supplied to the hydrodesulfurizer flows, a constant-volume raw material supplier that supplies the raw material to the hydrodesulfurizer, and a reformed gas from the reformer. The recycling path for supplying the raw material flowing through the raw material path upstream from the raw material feeder, and the flow rate of the raw material flowing through the raw material path upstream from the junction where the recycle gas from the recycling path flows The flow rate difference between the raw material flow rate measuring device, the raw material flow rate adjusting device that adjusts the flow rate of the raw material passing through the raw material flow rate measuring device, and the raw material flow rate measured by the discharge flow rate of the raw material supply device, The amount of difference set in advance As such, and a controller for controlling the material flow regulator and raw material supplier.

  With this configuration, when supplying an appropriate amount of recycle gas necessary for the hydrodesulfurization reaction to the raw material, the flow rate of the raw material containing the recycle gas can be appropriately controlled as compared with the conventional case.

  In other words, the raw material flow rate regulator can be used to adjust the raw material flow rate to a desired amount, and the constant volume type raw material feeder can be used to supply a certain amount of recycled gas-containing raw material to the hydrodesulfurizer and reformer. Can supply. Thereby, it is possible to control the flow rate difference between the raw material flow rate before the recycle gas is added and the raw material flow rate after the recycle gas is added to a preset difference amount.

  As described above, the recycle gas amount necessary for the hydrodesulfurizer can be ensured with the above flow rate difference, and a desired amount of raw material flow rate necessary for power generation of the fuel cell can be secured, so that the fuel cell system can be stably operated.

  Hereinafter, a specific example of the first embodiment will be described with reference to the drawings.

[Device configuration]
FIG. 1 is a diagram illustrating an example of a fuel cell system according to the first embodiment.

  As shown in FIG. 1, the fuel cell system 100 includes a fuel cell 1, a reformer 2, a hydrodesulfurizer 3, a raw material path 4, a recycling path 5, a raw material supplier 6, and a raw material flow rate measurement. A vessel 7, a raw material flow rate regulator 8, and a controller 9.

  The fuel cell 1 generates power using the hydrogen-containing reformed gas (anode gas) generated by the reformer 2. The fuel cell 1 includes a gas supply mechanism used for supplying a cathode gas such as air for power generation and an anode gas for power generation, a preheating mechanism for cathode gas, and an exhaust gas used for discharging the anode gas and cathode gas after use of power generation. A discharge mechanism and a water recovery mechanism for recovering water from the cathode offgas and the anode offgas are provided, which are known. Therefore, detailed description of the configuration is omitted.

  The fuel cell 1 may be any type. Examples of the fuel cell 1 include a polymer electrolyte fuel cell, a solid oxide fuel cell, and a phosphoric acid fuel cell. When the fuel cell 1 is a solid oxide fuel cell, the reformer 2 and the fuel cell 1 may be built in one container.

  The hydrodesulfurizer 3 removes sulfur components in the raw material. In the hydrodesulfurizer 3, a container is filled with a hydrodesulfurization agent. As the hydrodesulfurization agent, for example, a hydrogenation catalyst containing copper and zinc can be used. The hydrodesulfurization agent is not limited to this example, and may be a Ni-Mo-based or Co-Mo-based catalyst combined with a zinc oxide-based catalyst. In the case where the hydrodesulfurization agent contains copper and zinc, the hydrodesulfurizer 3 has an appropriate operating range of about 150 ° C to 350 ° C. Therefore, the hydrodesulfurizer 3 is heated to a temperature in the vicinity of about 250 ° C. in order to effectively advance the hydrogenation reaction in the hydrodesulfurizer 3 under high temperature conditions. For example, the hydrodesulfurizer 3 is often heated with combustion exhaust gas after being used for heating the reformer 2. In addition, as a raw material, the fuel containing the organic compound comprised at least carbon and hydrogen, such as city gas or natural gas which has methane as a main component, and LPG, can be illustrated.

  The reformer 2 generates a reformed gas to be supplied to the fuel cell 1 using the raw material from the hydrodesulfurizer 3. Specifically, in the reformer 2, the raw material undergoes a reforming reaction to generate a hydrogen-containing reformed gas. The reforming reaction may be in any form. For example, examples of the reforming reaction include a steam reforming reaction, an autothermal reaction, and a partial oxidation reforming reaction. As the reforming catalyst of the reformer 2, for example, a Ru-based catalyst can be used. The reformed gas of the reformer 2 is sent to the fuel cell 1 through the reformed gas path as anode gas that is fuel when the fuel cell 1 generates power. As heat necessary for the reforming reaction, thermal energy discharged from the fuel cell 1 is used. For example, the heat of combustion caused by the combustion of the cathode offgas and anode offgas discharged from the fuel cell 1 may be used for heating the reformer 2.

  The recycle path 5 is a flow path for supplying a part of the reformed gas from the reformer 2 as a recycle gas to the raw material flowing through the raw material path 4 upstream of the raw material supplier 6. The upstream end of the recycle path 5 may be connected to any location as long as the reformed gas sent from the reformer 2 flows.

  The raw material supplier 6 is a constant volume type feeder that supplies the raw material to the hydrodesulfurizer 3. Specifically, the raw material supplier 6 sucks the raw material flowing through the raw material path 4 and the recycle gas flowing through the recycle path 5 branched from the raw material path 4 downstream of the reformer 2, and supplies the hydrodesulfurizer 3 to the hydrodesulfurizer 3. Supply raw materials containing a certain amount of recycled gas. The raw material supplier 6 may have any configuration as long as it is a constant volume type feeder that supplies the raw material to the hydrodesulfurizer 3. An example of the raw material supplier 6 is a constant displacement pump. The raw material is supplied from a raw material supply source. The raw material supply source has a predetermined supply pressure. Examples of the raw material supply source include a raw material cylinder and a raw material infrastructure. For example, natural gas may be used as a raw material by connecting a natural gas infrastructure to the upstream end of the raw material path 4.

  The raw material flow rate measuring instrument 7 measures the flow rate of the raw material flowing through the raw material path 4 upstream from the joining portion 11 into which the recycle gas from the recycle path 5 flows. The raw material flow rate measuring device 7 may have any configuration as long as it can measure the flow rate of the raw material flowing through the raw material path 4 upstream from the merging portion 11. Examples of the raw material flow rate measuring device 7 include a flow meter. As a flow meter, the mass flow meter etc. which measure the mass flow rate of a raw material can be illustrated, for example.

  The raw material flow rate adjuster 8 adjusts the flow rate of the raw material passing through the raw material flow rate measuring device 7. The raw material flow rate adjuster 8 may have any configuration as long as the flow rate of the raw material passing through the raw material flow rate measuring device 7 can be adjusted.

  The controller 9 controls the raw material flow rate adjuster 8 and the raw material supply device so that the flow rate difference between the discharge flow rate of the raw material supply device 6 and the raw material flow rate measured by the raw material flow rate measuring device 7 becomes a preset difference amount. 6 is controlled. The controller 9 may have any configuration as long as it has a control function. The controller 9 includes an arithmetic processing unit (not shown) and a storage unit (not shown) that stores a control program. Examples of the arithmetic processing unit include an MPU and a CPU. Examples of the storage unit include a memory. The controller 9 may be composed of a single controller that performs centralized control, or may be composed of a plurality of controllers that perform distributed control.

[Operation]
FIG. 2 is a flowchart showing an example of the operation of the fuel cell system of the first embodiment. The following operations are performed by the control program of the controller 9.

  During operation of the fuel cell system 100, when the raw material flowing through the raw material path 4 is sucked into the raw material supply device 6, a part of the reformed gas from the reformer 2 is used as a recycle gas and is supplied to the raw material via the recycle path 5. Supplied. As a result, the recycle gas is mixed with the raw material, the pressure of the recycle gas-containing material is increased by the material supply device 6, and a certain volume of the recycle gas-containing material is sent to the hydrodesulfurizer 3. When the recycle gas is supplied to the hydrodesulfurizer 3, the hydrodesulfurizer 3 can remove sulfur compounds in the raw material by a hydrogenation reaction. In the reformer 2, a hydrogen-containing reformed gas is generated by the reforming reaction of the raw material from the hydrodesulfurizer 3 and is supplied to the fuel cell 1 through the reformed gas path. In the fuel cell 1, reformed gas (anode gas) and air (cathode gas) necessary for power generation are supplied, whereby the fuel cell 1 generates power. The cathode gas supplied to the fuel cell 1 is a heat exchanger (not shown) provided in the unit of the fuel cell 1 and reaches a temperature required for the operation of the fuel cell 1 using heat generated during power generation of the fuel cell 1. Preheated and sent to the fuel cell 1.

  The above-described series of operations is performed by operating auxiliary devices necessary for the operation under the control of the controller 9, and the operation of supplying electric power and heat is performed in the same manner as the operation of the conventional fuel cell system 100. .

  Here, as described above, stable generation of reformed gas is important for stable operation of the fuel cell 1. For stable generation of the reformed gas, hydrogen (reformed gas) is added to the raw material within a certain amount range in order to ensure the performance of the hydrodesulfurizer 3 that prevents sulfur poisoning of the reforming catalyst ( Need to be recycled). Moreover, the supply amount of the raw material containing the recycle gas sent to the reformer 2 affects the heat balance and the steam carbon ratio (S / C ratio) in the reformer 2. For example, when the amount of the recycle gas is large, it is necessary to heat a large amount of the recycle gas to a temperature necessary for the reforming reaction, and the necessary heat amount in the reformer 2 increases. Further, since the recycle gas contains water vapor, the recycle gas flowing through the recycle path 5 may be dehumidified in order to prevent condensation on the recycle path 5. In this case, when the variation in the amount of recycled gas is large, the balance of the S / C ratio in the reformer 2 is lost. Therefore, it is necessary to suppress variations in the amount of gas supplied to the reformer 2.

  Therefore, in this embodiment, the raw material flow rate measuring device 7 measures the raw material flow rate of the raw material sent from a raw material supply source (not shown). In addition, the discharge flow rate of the constant volume type material supply device 6 is acquired by the controller 9. For example, the controller 9 can grasp the discharge flow rate based on a control signal to the raw material supplier 6.

  Then, as shown in FIG. 2, in step S1, whether or not the flow rate difference between the discharge flow rate of the raw material supplier 6 and the raw material flow rate measured by the raw material flow rate measuring instrument 7 is a preset difference amount. Determined. The difference amount set in advance in step S1 may be an appropriate setting range set according to the operating conditions of the fuel cell system 100, or may be an appropriate setting reference value.

  For example, when the difference amount set in advance is an appropriate setting range, the upper limit value and the lower limit value of the setting range may be set as follows.

  The lower limit of the setting range is set to a value that can secure the amount of hydrogen required for the hydrogenation reaction in the hydrodesulfurizer 3, and the upper limit is the heat balance in the reforming reaction of the reformer 2, the steam carbon ratio, etc. Set the value within a range where the influence is reduced. For example, the lower limit is set so that the hydrogen concentration in the recycled gas-containing raw material is 2% or more of the raw material, and the upper limit is 10% in consideration of the heat balance in the reformer 2. % May be set to be less than or equal to%. In addition, the numerical values of the upper limit value and the lower limit value of such a setting range are examples and are not limited to this example.

  However, it is better to set the width of the setting range (the difference between the upper limit value and the lower limit value) as small as possible. Furthermore, the operation of the fuel cell system 100 reacts sensitively by setting the upper limit value and the lower limit value of the flow rate range in consideration of the measurement error of the raw material flow rate measuring device 7 and the discharge flow rate error of the raw material supply device 6. It is also possible to operate the fuel cell system 100 stably.

  Here, when the flow rate difference in step S1 is a preset difference amount, the operation of the fuel cell system 100 is continued as it is (step S3).

  On the other hand, if the flow rate difference in step S1 is not a preset difference amount, the raw material flow rate regulator 8 and the raw material supplier 6 are controlled in step S2 so that the flow rate difference becomes a preset difference amount. Is done. Specifically, the operation amounts of the raw material flow rate adjuster 8 and the raw material supply device 6 are changed. For example, if the raw material flow regulator 8 is a pressure regulating valve, the opening degree of the pressure regulating valve is changed.

  As described above, in this embodiment, when an appropriate amount of recycle gas necessary for the hydrodesulfurization reaction is supplied to the raw material, the flow rate of the raw material containing the recycle gas can be appropriately controlled as compared with the conventional case.

  In other words, the raw material flow rate regulator 8 can be used to adjust the raw material flow rate to a desired amount, and the constant volume type raw material feeder 6 can be used to supply a certain amount of the recycled gas-containing raw material, the hydrodesulfurizer 3 and the reformer. It can be supplied to the quality device 2. Thus, the flow rate difference between the raw material flow rate before the recycle gas is added and the raw material flow rate after the recycle gas is added can be controlled to be a preset difference amount.

  As described above, the amount of recycle gas necessary for the hydrodesulfurizer 3 can be secured with the above-mentioned flow rate difference, and a desired amount of raw material flow required for power generation of the fuel cell 1 can be secured, so that the fuel cell system 100 can be operated stably. Can do.

  Note that the discharge flow rate of the raw material supply unit 6 is as long as the recycle gas amount necessary for the hydrodesulfurizer 3 is secured with the above flow rate difference, and a desired amount of raw material flow rate necessary for power generation of the fuel cell 1 can be secured. It is not necessarily strictly quantitative. For example, the discharge flow rate of the constant displacement pump may change due to fluctuations in the raw material pressure (pressure of the raw material flowing in the raw material path 4) and the raw material temperature (temperature of the raw material flowing in the raw material path 4). In this case, for example, in an environment where the ambient temperature of the fuel cell system 100 changes significantly, the raw material path 4 is provided with a detector for detecting the raw material pressure and a detector for detecting the raw material temperature. The operation of the raw material supplier 6 may be adjusted based on the data. As a result, even in an environment where the ambient temperature of the fuel cell system 100 changes significantly, the recycled gas-containing raw material can be quantified and supplied to the hydrodesulfurizer 3 and the reformer 2 with high accuracy.

Example 1
The fuel cell system of Example 1 of Embodiment 1 is the same as the fuel cell system of Embodiment 1, but the raw material flow rate regulator is provided in the recycling path, and the first pressure regulator for adjusting the pressure of the recycled gas The controller operates the first pressure regulator so that the raw material flow rate measured by the raw material flow rate measuring device becomes a preset flow rate based on the power generation amount of the fuel cell, and the discharge of the raw material supply device The raw material supplier is operated so that the flow rate becomes a preset flow rate based on the power generation amount of the fuel cell.

  According to such a configuration, the pressure loss of the recycling path can be adjusted by the first pressure regulator so that the raw material flow rate measured by the raw material flow rate measuring device becomes a flow rate necessary for power generation of the fuel cell. That is, when the amount of the raw material containing the recycle gas is fixed, by controlling the recycle gas flow rate, the flow rate of the raw material flowing through the raw material path can be adjusted to a desired amount.

  Further, by using a constant volume type material supply device, the discharge flow rate of the material supply device can be adjusted to a flow rate necessary for power generation of the fuel cell.

  The fuel cell system of this example may be configured in the same manner as the fuel cell system of the first embodiment except for the above characteristics.

[Device configuration]
FIG. 3 is a diagram illustrating an example of a fuel cell system according to Example 1 of the first embodiment.

  As shown in FIG. 3, the fuel cell system 100 includes a fuel cell 1, a reformer 2, a hydrodesulfurizer 3, a raw material path 4, a recycling path 5, a raw material supplier 6, and a raw material flow rate measurement. A device 7, a first pressure regulator 8 </ b> A, and a controller 9 are provided. Since the fuel cell 1, the reformer 2, the hydrodesulfurizer 3, the raw material path 4, the recycling path 5, the raw material supplier 6 and the raw material flow rate measuring instrument 7 are the same as those in the first embodiment, the description thereof will be omitted.

  In the present embodiment, the raw material flow rate adjuster 8 is a first pressure adjuster 8A that is provided in the recycle path 5 and adjusts the pressure of the recycle gas. The first pressure regulator 8A may have any configuration as long as the pressure of the recycle gas can be adjusted. As the first pressure regulator 8A, for example, a pressure regulating valve for regulating the pressure loss of the recycling path 5 can be exemplified. Examples of the pressure regulating valve include a needle valve.

  The controller 9 operates the first pressure regulator 8A so that the raw material flow rate measured by the raw material flow rate measuring device 7 becomes a flow rate set in advance based on the power generation amount of the fuel cell 1, and the raw material supply device 6 The raw material supplier 6 is operated so that the discharge flow rate of the fuel becomes a flow rate set in advance based on the power generation amount of the fuel cell 1.

  As described above, the pressure loss of the recycle path 5 can be adjusted by the first pressure regulator 8 </ b> A so that the raw material flow rate measured by the raw material flow rate measuring device 7 becomes a flow rate necessary for power generation of the fuel cell 1. That is, if the amount of the recycled gas-containing raw material is fixed, the flow rate of the raw material flowing through the raw material path 4 can be adjusted to a desired amount by controlling the flow rate of the recycled gas.

  Further, by using the constant volume type material supply device 6, the discharge flow rate of the material supply device 6 can be adjusted to a flow rate necessary for power generation of the fuel cell 1. That is, the constant volume type raw material supply device 6 can quantitatively supply the recycled raw material to the hydrodesulfurizer 3 and the reformer 2 without changing the pressure loss of the recycle path 5. Thus, the flow rate difference between the raw material flow rate before the recycle gas is added and the raw material flow rate after the recycle gas is added can be controlled to be a preset difference amount.

  Therefore, the recycle gas amount necessary for the hydrodesulfurizer 3 can be ensured with the above flow rate difference, and a desired amount of raw material flow rate necessary for power generation of the fuel cell 1 can be secured, so that the fuel cell system 100 can be operated stably. obtain.

(Example 2)
The fuel cell system of Example 2 of the first embodiment is the same as the fuel cell system of the first embodiment, wherein the raw material flow rate regulator is provided in the raw material path upstream from the junction, and the pressure of the raw material flowing through the raw material path is adjusted. A second pressure regulator for adjusting the second pressure regulator so that the raw material flow rate measured by the raw material flow rate meter is a flow rate set in advance based on the power generation amount of the fuel cell. And the raw material supplier is operated so that the discharge flow rate of the raw material supplier becomes a flow rate set in advance based on the power generation amount of the fuel cell.

  According to such a configuration, the pressure loss of the raw material path can be adjusted by the second pressure regulator so that the raw material flow rate measured by the raw material flow rate measuring device becomes a flow rate necessary for power generation of the fuel cell.

  Further, by using a constant volume type material supply device, the discharge flow rate of the material supply device can be adjusted to a flow rate necessary for power generation of the fuel cell.

  The fuel cell system of this example may be configured in the same manner as the fuel cell system of the first embodiment except for the above characteristics.

[Device configuration]
FIG. 4 is a diagram illustrating an example of a fuel cell system according to Example 2 of the first embodiment.

  As shown in FIG. 4, the fuel cell system 100 includes a fuel cell 1, a reformer 2, a hydrodesulfurizer 3, a raw material path 4, a recycling path 5, a raw material supplier 6, and a raw material flow rate measurement. A device 7, a second pressure regulator 8 </ b> B, and a controller 9 are provided. Since the fuel cell 1, the reformer 2, the hydrodesulfurizer 3, the raw material path 4, the recycling path 5, the raw material supplier 6 and the raw material flow rate measuring instrument 7 are the same as those in the first embodiment, the description thereof will be omitted.

  In the present embodiment, the raw material flow rate regulator 8 is a second pressure regulator 8 </ b> B that is provided in the raw material path 4 upstream of the merging portion 11 and adjusts the pressure of the raw material flowing through the raw material path 4. The second pressure regulator 8B may have any configuration as long as the pressure of the recycle gas can be adjusted. As the second pressure regulator 8B, for example, a pressure regulating valve for regulating the pressure loss of the raw material path 4 can be exemplified. Examples of the pressure regulating valve include a needle valve. Further, the second pressure regulator 8 </ b> B may be provided at any location as long as it is the raw material path 4 upstream from the merging portion 11. For example, in the present embodiment, the second pressure regulator 8B is provided in the raw material path 4 between the raw material flow rate measuring instrument 7 and the junction portion 11, but the second pressure regulator is the raw material flow rate measuring instrument 7. It may be provided in the raw material path 4 upstream.

  The controller 9 operates the second pressure regulator 8B so that the raw material flow rate measured by the raw material flow rate measuring device 7 becomes a flow rate set in advance based on the power generation amount of the fuel cell 1, and the raw material supply device 6 The raw material supplier 6 is operated so that the discharge flow rate of the fuel becomes a flow rate set in advance based on the power generation amount of the fuel cell 1.

  By the above, the pressure loss of the raw material path | route 4 can be adjusted with the 2nd pressure regulator 8B so that the raw material flow volume measured with the raw material flow volume measuring device 7 may turn into a flow volume required for the electric power generation of the fuel cell 1.

  In addition, the discharge flow rate of the constant volume type material supply device 6 can be adjusted to a flow rate required for power generation of the fuel cell 1. That is, the constant volume type raw material supply device 6 can quantitatively supply the recycled raw material to the hydrodesulfurization unit 3 and the reformer 2 without depending on the pressure loss of the raw material path 4. Thus, the flow rate difference between the raw material flow rate before the recycle gas is added and the raw material flow rate after the recycle gas is added can be controlled to be a preset difference amount.

  Therefore, the recycle gas amount necessary for the hydrodesulfurizer 3 can be ensured with the above flow rate difference, and a desired amount of raw material flow rate necessary for power generation of the fuel cell 1 can be secured, so that the fuel cell system 100 can be operated stably. obtain.

(Embodiment 2)
The fuel cell system according to the second embodiment is the same as the fuel cell system according to the first embodiment, in which the temperature detector for detecting the temperature of the reformer and the combustion heat of the anode off gas of the fuel cell are used to heat the reformer. A combustor, and the controller detects the temperature of the raw material flow rate measured by the raw material flow rate measuring device when the raw material flow rate is within a preset flow rate range based on the power generation amount of the fuel cell. The raw material flow controller is operated so that the detected temperature becomes a preset temperature, and the difference between the discharge flow rate of the raw material feeder and the raw material flow rate measured by the raw material flow meter is a preset difference. The raw material feeder is operated so as to obtain a quantity.

  According to this configuration, on the assumption that the raw material flow rate measured by the raw material flow rate measuring device is within the flow rate range necessary for power generation of the fuel cell, the raw material flow rate flowing through the raw material path is determined based on the operation of the raw material flow rate regulator. Fine control. As a result, the anode off-gas amount from the fuel cell to the combustor can be controlled so that the amount of heat necessary for the reforming reaction of the reformer becomes an appropriate amount. Therefore, compared with the case where such control is not performed, the reformed gas generation of the reformer can be stabilized.

  In addition, by using a constant volume type material supply device, a certain amount of the material containing the recycle gas can be supplied to the hydrodesulfurizer and the reformer. Thereby, it is possible to control the flow rate difference between the raw material flow rate before the recycle gas is added and the raw material flow rate after the recycle gas is added to a preset difference amount.

  As described above, the recycle gas amount necessary for the hydrodesulfurizer can be ensured with the above flow rate difference, and a desired amount of raw material flow rate necessary for power generation of the fuel cell can be secured, so that the fuel cell system can be stably operated.

  The fuel cell system of the present embodiment may be configured in the same manner as the fuel cell system of the first embodiment except for the above features.

[Device configuration]
FIG. 5 is a diagram illustrating an example of a fuel cell system according to the second embodiment.

  As shown in FIG. 5, the fuel cell system 100 includes a fuel cell 1, a reformer 2, a hydrodesulfurizer 3, a raw material path 4, a recycling path 5, a raw material supplier 6, and a raw material flow rate measurement. A vessel 7, a raw material flow rate regulator 8, a controller 9, a temperature detector 10, and a combustor 12. Since the fuel cell 1, the reformer 2, the hydrodesulfurizer 3, the raw material path 4, the recycling path 5, the raw material supplier 6, the raw material flow rate measuring instrument 7, and the raw material flow controller 8 are the same as those in the first embodiment. Description is omitted.

  The temperature detector 10 detects the temperature of the reformer 2. The temperature detector 10 may have any configuration as long as the temperature of the reformer 2 can be detected directly or indirectly. That is, the temperature detector 10 may be provided in the reformer 2 and the temperature of the reformer 2 may be directly detected, or the temperature detector 10 is provided at a predetermined location correlated with the temperature of the reformer 2. The temperature of the reformer 2 may be detected indirectly. Examples of the temperature detector 10 include a thermocouple and a thermistor.

  The combustor 12 heats the reformer 2 using the combustion heat of the anode off gas of the fuel cell 1. For example, the anode offgas and cathode offgas of the fuel cell 1 are supplied to the combustor 12 as fuel. The combustor 12 may have any configuration as long as the reformer 2 can be heated using the combustion heat of the anode off gas. For example, the combustor 12 may be a premixed combustion burner that supplies anode offgas and cathode offgas mixed in advance externally, or a diffusion combustion burner that supplies these separately and mixes them internally. Good.

  The controller 9 detects the detected temperature detected by the temperature detector 10 when the raw material flow rate measured by the raw material flow rate measuring device 7 is within a flow rate range set in advance based on the power generation amount of the fuel cell 1. The raw material flow rate adjuster 8 is operated so as to reach a preset temperature, and the difference in flow rate between the discharge flow rate of the raw material supply device 6 and the raw material flow rate measured by the raw material flow rate measuring instrument 7 is set as a preset difference amount. The raw material supplier 6 is operated so that

[Operation]
FIG. 6 is a flowchart showing an example of the operation of the fuel cell system of the second embodiment. The following operations are performed by the control program of the controller 9.

  In the present embodiment, a series of operations similar to those in the first embodiment are performed by operating the auxiliary machinery necessary for the operation under the control of the controller 9, and like the operation of the conventional fuel cell system 100, The operation of supplying power and heat is performed.

  At this time, excess cathode offgas and anode offgas generated by the power generation of the fuel cell 1 are combusted in the combustor 12. The combustion heat generated by the combustion of the anode off gas is used for the reforming reaction of the reformer 2. Further, the combustion exhaust gas to which heat necessary for the reforming reaction is given is sent to the hydrodesulfurizer 3, and the heat of this combustion exhaust gas is used for heating the hydrodesulfurization agent of the hydrodesulfurizer 3.

  Here, when the power generation amount of the fuel cell 1 increases, the anode off-gas amount sent to the combustor 12 decreases if the raw material flow rate flowing through the raw material path 4 is constant. As a result, the amount of heat used for heating the reformer 2 may be insufficient, and the temperature of the reformer 2 may be lower than a preset temperature (appropriate temperature).

  Conversely, when the amount of power generated by the fuel cell 1 decreases, the amount of anode off-gas sent to the combustor 12 increases if the flow rate of the raw material flowing through the raw material path 4 is constant. As a result, the amount of heat used for heating in the reformer 2 may exceed, and the temperature of the reformer 2 may exceed the appropriate temperature.

  Therefore, in this embodiment, when the raw material flow rate measured by the raw material flow rate measuring device 7 is within a flow rate range set in advance based on the power generation amount of the fuel cell 1, the temperature detector 10 causes the reformer 2 to The flow rate of the raw material flowing through the raw material path 4 is adjusted within the above flow rate range so that the temperature detected by the temperature detector 10 becomes a preset temperature.

  Specifically, as shown in FIG. 6, in step S4, it is determined whether or not the detected temperature detected by the temperature detector 10 is a preset temperature. The temperature set in advance in step S4 may be an appropriate setting range set according to the operating conditions of the fuel cell system 100, or may be an appropriate setting reference value.

  The temperature of the reformer 2 affects the conversion rate (reaction rate) of the raw material in the reformer 2. Therefore, the preset temperature in step S4 is the temperature at which the hydrogen concentration in the reformed gas necessary for power generation of the fuel cell 1 can be secured, and the reformed gas in order to maintain the operating temperature in the fuel cell 1. It is better to set the temperature to ensure the methane concentration. In this embodiment, the preset temperature is set to about 630 ° C. In addition, the numerical value of this preset temperature is an illustration, Comprising: It is not limited to this example.

  If the detected temperature in step S4 is not a preset temperature, the raw material flow rate regulator 8 is controlled in step S5 so that the detected temperature becomes a preset temperature. Specifically, the operation amount of these raw material flow rate regulators 8 is changed. For example, if the raw material flow regulator 8 is a pressure regulating valve, the opening degree of the pressure regulating valve is changed.

  When the detected temperature in step S4 is a preset temperature, the process proceeds to the next determination step, and in step S1A, the flow rate difference between the discharge flow rate of the raw material supply device 6 and the raw material flow rate measured by the raw material flow rate measuring device 7 is reached. Is a difference amount set in advance. Since step S1A of the present embodiment is the same as step S1 of the first embodiment, detailed description thereof is omitted.

  When the flow rate difference in step S1A is a preset difference amount, the operation of the fuel cell system 100 is continued as it is (step S3).

  When the flow rate difference in step S1A is not a preset difference amount, in step S2A, the raw material supplier 6 is controlled so that the flow rate difference becomes a preset difference amount. Specifically, the operation amount of the raw material supplier 6 is changed.

  As described above, the present embodiment is based on the operation of the raw material flow rate regulator 8 on the assumption that the raw material flow rate measured by the raw material flow rate measuring instrument 7 is within the flow rate range necessary for power generation of the fuel cell 1. Thus, the flow rate of the raw material flowing through the raw material path 4 can be finely controlled. As a result, the anode off-gas amount from the fuel cell 1 to the combustor 12 can be controlled so that the amount of heat necessary for the reforming reaction of the reformer 2 becomes an appropriate amount. Therefore, compared with the case where such control is not performed, the reformed gas generation of the reformer 2 can be stabilized.

  Further, by using the constant volume type raw material supplier 6, a certain amount of the raw material containing the recycle gas can be supplied to the hydrodesulfurizer 3 and the reformer 2. Thereby, it is possible to control the flow rate difference between the raw material flow rate before the recycle gas is added and the raw material flow rate after the recycle gas is added to a preset difference amount.

  As described above, the amount of recycle gas necessary for the hydrodesulfurizer 3 can be secured with the above-mentioned flow rate difference, and a desired amount of raw material flow required for power generation of the fuel cell 1 can be secured, so that the fuel cell system 100 can be operated stably. Can do.

Example 1
The fuel cell system of Example 1 of Embodiment 2 is the same as the fuel cell system of Embodiment 2, but the raw material flow rate regulator is provided in the recycle path, and the first pressure regulator for adjusting the pressure of the recycle gas The controller operates the first pressure regulator so that the detected temperature detected by the temperature detector becomes a preset temperature, and the discharge flow rate of the raw material supplier becomes the power generation amount of the fuel cell. Based on this, the raw material feeder is operated so as to be within a preset flow rate range.

  According to such a configuration, it is possible to finely adjust the pressure loss of the recycle path by the first pressure regulator on the assumption that the raw material flow rate measured by the raw material flow rate meter is within the flow rate range necessary for power generation of the fuel cell. That is, when the amount of the raw material containing the recycle gas is fixed, by controlling the recycle gas flow rate, the flow rate of the raw material flowing through the raw material path can be adjusted to a desired amount. As a result, the anode off-gas amount from the fuel cell to the combustor can be controlled so that the amount of heat necessary for the reforming reaction of the reformer becomes an appropriate amount. Therefore, compared with the case where such control is not performed, the reformed gas generation of the reformer can be stabilized.

  The fuel cell system of this example may be configured in the same manner as the fuel cell system of Embodiment 2 except for the above features.

[Device configuration]
FIG. 7 is a diagram illustrating an example of a fuel cell system according to Example 1 of the second embodiment.

  As shown in FIG. 7, the fuel cell system 100 includes a fuel cell 1, a reformer 2, a hydrodesulfurizer 3, a raw material path 4, a recycle path 5, a raw material supplier 6, and a raw material flow rate measurement. A device 7, a first pressure regulator 8 </ b> A, a controller 9, a temperature detector 10, and a combustor 12 are provided. Since the fuel cell 1, the reformer 2, the hydrodesulfurizer 3, the raw material path 4, the recycling path 5, the raw material supplier 6 and the raw material flow rate measuring instrument 7 are the same as those in the first embodiment, the description thereof will be omitted. Further, the first pressure regulator 8A is the same as that of the first embodiment of the first embodiment, and hence the description thereof is omitted. Furthermore, since the temperature detector 10 and the combustor 12 are the same as those in the second embodiment, description thereof will be omitted.

  In the present embodiment, the controller 9 operates the first pressure regulator so that the detected temperature detected by the temperature detector 10 becomes a preset temperature, and the discharge flow rate of the raw material supply device 6 is the fuel flow rate. The raw material supplier 6 is operated so as to be within a preset flow rate range based on the power generation amount of the battery 1.

  As described above, the pressure loss of the recycle path 5 can be finely adjusted by the first pressure regulator 8A on the assumption that the raw material flow rate measured by the raw material flow rate measuring device 7 is within the flow rate range necessary for power generation of the fuel cell 1. . That is, if the amount of the recycled gas-containing raw material is fixed, the flow rate of the raw material flowing through the raw material path 4 can be adjusted to a desired amount by controlling the flow rate of the recycled gas. As a result, the anode off-gas amount from the fuel cell 1 to the combustor 12 can be controlled so that the amount of heat necessary for the reforming reaction of the reformer 2 becomes an appropriate amount. Therefore, compared with the case where such control is not performed, the reformed gas generation of the reformer 2 can be stabilized.

(Example 2)
The fuel cell system of Example 2 of the second embodiment is the same as the fuel cell system of the second embodiment, wherein the raw material flow rate regulator is provided in the raw material path upstream from the junction, and the pressure of the raw material flowing through the raw material path is adjusted. A second pressure regulator for adjusting, and the controller operates the second pressure regulator so that the detected temperature detected by the temperature detector becomes a preset temperature, and the discharge of the raw material supplier The raw material supplier is operated so that the flow rate falls within a flow rate range set in advance based on the power generation amount of the fuel cell.

  According to such a configuration, it is possible to finely adjust the pressure loss of the raw material path by the second pressure regulator on the assumption that the raw material flow rate measured by the raw material flow rate measuring device is in a flow rate range necessary for power generation of the fuel cell. As a result, the anode off-gas amount from the fuel cell to the combustor can be controlled so that the amount of heat necessary for the reforming reaction of the reformer becomes an appropriate amount. Therefore, compared with the case where such control is not performed, the reformed gas generation of the reformer can be stabilized.

  The fuel cell system of this example may be configured in the same manner as the fuel cell system of Embodiment 2 except for the above features.

[Device configuration]
FIG. 8 is a diagram illustrating an example of a fuel cell system according to Example 2 of the second embodiment.

  As shown in FIG. 8, the fuel cell system 100 includes a fuel cell 1, a reformer 2, a hydrodesulfurizer 3, a raw material path 4, a recycling path 5, a raw material supplier 6, and a raw material flow rate measurement. And a combustor 12, a second pressure regulator 8B, a controller 9, a temperature detector 10, and a combustor 12. Since the fuel cell 1, the reformer 2, the hydrodesulfurizer 3, the raw material path 4, the recycling path 5, the raw material supplier 6 and the raw material flow rate measuring instrument 7 are the same as those in the first embodiment, the description thereof will be omitted. The second pressure regulator 8B is the same as that of Example 2 of the first embodiment, and a description thereof will be omitted. Furthermore, since the temperature detector 10 and the combustor 12 are the same as those in the second embodiment, description thereof will be omitted.

  In this embodiment, the controller 9 operates the second pressure regulator 8B so that the detected temperature detected by the temperature detector 10 becomes a preset temperature, and the discharge flow rate of the raw material supplier 6 is The raw material supplier 6 is operated so that the flow rate is set in advance based on the power generation amount of the fuel cell 1.

  As described above, the pressure loss of the raw material path 4 can be finely adjusted by the second pressure regulator 8B on the assumption that the raw material flow rate measured by the raw material flow rate measuring device 7 is within the flow rate range necessary for power generation of the fuel cell 1. . As a result, the anode off-gas amount from the fuel cell 1 to the combustor 12 can be controlled so that the amount of heat necessary for the reforming reaction of the reformer 2 becomes an appropriate amount. Therefore, compared with the case where such control is not performed, the reformed gas generation of the reformer 2 can be stabilized.

  According to one embodiment of the present invention, when an appropriate amount of recycle gas necessary for hydrodesulfurization reaction is supplied to a raw material, the flow rate of the raw material containing the recycle gas can be appropriately controlled as compared with the conventional case. Thus, one embodiment of the present invention can be used, for example, in a fuel cell system.

1: Fuel cell 2: Reformer 3: Hydrodesulfurizer 4: Raw material path 5: Recycling path 6: Raw material feeder 7: Raw material flow meter 8: Raw material flow controller 8A: First pressure regulator 8B: First 2 pressure regulator 9: controller 10: temperature detector 11: junction 12: combustor 100: fuel cell system

Claims (3)

A fuel cell;
A hydrodesulfurizer for removing sulfur components in the raw material;
A reformer that generates a reformed gas to be supplied to the fuel cell using the raw material from the hydrodesulfurizer;
A raw material path through which a raw material supplied to the hydrodesulfurizer flows;
A constant-volume raw material supplier for supplying raw material to the hydrodesulfurizer;
Recycle path for supplying a part of the reformed gas from the reformer as a recycle gas to the raw material flowing through the raw material path upstream from the raw material supply unit;
A raw material flow rate measuring device for measuring the flow rate of the raw material flowing through the raw material path upstream from the joining portion into which the recycle gas from the recycling path flows;
A raw material flow controller for adjusting the flow rate of the raw material passing through the raw material flow meter;
A temperature detector for detecting the temperature of the reformer;
A combustor that heats the reformer using combustion heat of the anode offgas of the fuel cell;
When the raw material flow rate measured by the raw material flow rate measuring device is within a flow rate range set in advance based on the power generation amount of the fuel cell, the detection temperature detected by the temperature detector is preset. Operate the raw material flow rate regulator so as to reach a temperature, so that the difference in flow rate between the discharge flow rate of the raw material supply device and the raw material flow rate measured by the raw material flow rate meter becomes a preset difference amount, A fuel cell system comprising: a controller that operates the raw material supplier . The raw material flow rate regulator is a first pressure regulator for adjusting the pressure of the recycle gas provided in the recycling path,
The controller operates the first pressure regulator so that a detected temperature detected by the temperature detector becomes a preset temperature, and a discharge flow rate of the raw material supplier is set to generate power of the fuel cell. the fuel cell system according to claim 1 for operating the raw material supply unit to be within the flow rate range the set in advance based on an amount. The raw material flow rate regulator is a second pressure regulator for adjusting the pressure of the raw material provided in the raw material path upstream of the merging portion and flowing through the raw material path,
The controller operates the second pressure regulator so that a detected temperature detected by the temperature detector becomes a preset temperature, and a discharge flow rate of the raw material supplier is set to generate power of the fuel cell. the fuel cell system according to claim 1 for operating the raw material supply unit to be within the flow rate range the set in advance based on an amount.

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