JP3682884B1 - Fuel cell power generation system provided with hydrogen storage device and fuel cell power generation method thereof - Google Patents

Abstract

A hydrogen storage device is produced by reducing the capacity of a fuel reformer to reduce the size of the system, reducing fuel during start-up of the reformer, and operating the reformer in an efficient range. A fuel cell power generation system is provided.
SOLUTION: A fuel cell, a reformer, a hydrogen pipe for supplying generated hydrogen to the fuel cell, an air pipe for supplying oxygen in the air to the fuel cell, and a hydrogen storage device 2 in the middle of the hydrogen pipe. . In one day, the reformer 1 is started only once, is steadily operated for a certain period, and then completely stopped. When the start-up of the reformer starts, the start-up is started, and the required hydrogen amount is generated by steady-state operation of the reformer, the power demand is covered by the fuel cell, and hydrogen is stored in the hydrogen storage device. A fuel cell power generation system in which the power demand is covered with hydrogen stored in the hydrogen storage device until the start of the start of the next fuel reformer.
[Selection] Figure 1

Description

The present invention relates to a fuel cell power generation system and a fuel cell power generation method in which a hydrogen storage device is installed in a fuel cell system (also referred to as a cogeneration system when an exhaust heat recovery device is provided).

The fuel cell power generation system has attracted attention as a power generation system with high power generation efficiency. When the thermal energy held by the exhaust gas discharged from the fuel cell power generation system is recovered as exhaust heat, the fuel cell system becomes a cogeneration system with higher energy utilization efficiency. The fuel cell power generation system is also characterized by being a power generation system with low noise during operation.
In the conventional fuel cell power generation system, in order to generate hydrogen in the fuel reformer corresponding to the power generation output of the fuel cell stack, it is necessary to provide a large capacity fuel reformer corresponding to the maximum power generation output of the fuel cell stack. there were. When the power consumption is low, the large-capacity fuel reformer is operated with a small load. The fuel cell stack can be operated without reducing the efficiency even in low-load operation, but the fuel reformer is very efficient when operated in a steady state, and the efficiency is lowered in low-load operation. In general, the efficiency decreases during low-load operation.

  On the contrary, the efficiency of the fuel reformer decreases even under high load operation, and the efficiency of the entire system generally decreases even under high load operation.

Japanese Utility Model Publication No. 63-29853 JP-A-9-266006 JP 2000-294264 A

In such a fuel cell system, the hydrogen production capacity of the fuel reformer needs to match the maximum hydrogen consumption of the fuel cell stack. The hydrogen consumption of the fuel cell stack fluctuates due to the increase or decrease in power demand. The electric power demand varies, for example, depending on the season of spring, summer, autumn and winter (seasonal variation), and varies depending on the day and night of the day (day-night variation). Therefore, when the power generation capacity of the fuel cell stack is matched to the maximum power demand of the power load, a large-capacity fuel reformer is required, increasing the size of the entire system, increasing capital investment, There arises a problem of an increase in fuel during the warm-up operation necessary for startup. There is also a problem that the fuel reformer must be operated at a low load with low efficiency for most of the time.

  The object of the present invention is to reduce the capacity of the fuel reformer to reduce the size of the system, reduce the capital investment, reduce the fuel during the warm-up operation of the fuel reformer, and make the fuel reformer efficient hydrogen. It is to provide a fuel cell power generation system and a fuel cell power generation method provided with an inexpensive, compact and highly efficient hydrogen storage device by operating within the range of generation amount.

Here, the terminology will be explained below in order to eliminate the doubt on the interpretation of the terminology used in the present specification, particularly the claimed invention.
[Explanation of terms]
The fuel cell power generation system includes a fuel cell stack that supplies electric power to an electric power load, a fuel reformer that generates hydrogen, a hydrogen storage device that stores hydrogen, and a control device. Furthermore, there is a case where an exhaust heat recovery device that recovers exhaust heat generated in the fuel cell stack is weighted on the requirement.
○ A control device is a fuel cell power generation system that starts a fuel reformer only once during a day, stops it completely for a certain period of time, and then stops completely. Then, start of the fuel reformer is started, the hydrogen amount H00 is generated so as to satisfy Formula (2) by steady operation of the fuel reformer, and the power demand is covered by the fuel cell stack, After hydrogen is stored in the hydrogen storage device, when the fuel reformer is completely stopped te = ts + to, the operation of the fuel reformer is completely stopped, and the next fuel reforming is performed after the fuel reformer is completely stopped te. During the start-up time ts of the device, the device controls the electric power demand so as to be covered with hydrogen stored in the hydrogen storage device.
Specifically, the control method is controlled according to the following procedure. In addition, the following control method is an illustration, Comprising: It is not necessarily limited to this.
<Preparation stage>
(1) An assumed power demand curve W0 (t) that is a function of time t is prepared in advance and stored in the memory M. The assumed power demand curve W0 (t) is generally prepared in advance by the previous day and stored in the memory M.
In practice, for example, t1 = 0, t2 = Δt... Tn = (n−1) Δt, and the corresponding W0 (t1), W0 (t2) t... W0 (tn) are stored in the memory M in advance. . When obtaining the function W0 (t) at an arbitrary time t, it is calculated by interpolation.
(2) Next, a curve H0 (t) of an assumed hydrogen amount necessary to generate the estimated power demand W0 (t) is calculated by substituting W = W0 (t) into the equation (1). And stored in the memory M.

  That is, the following expression is established.

H0 (t) = H (W0 (t)) = (W0 (t) / η (W0 (t))) / C Equation (1 ′)
In the above, strictly speaking, W = W0 (t) is given as data of a set of discrete values, and H0 (t) corresponding to W0 (t) is also calculated as data of a set of discrete values. Both data are stored in the memory M in advance.
The control device calculates H0 (t) when an arbitrary time t is given by arithmetic processing such as an interpolation method based on a set of discrete values of H0 (t).
(3) The fuel reformer start time ts and the fuel reformer complete stop time te = ts + to are determined, and both are stored in the memory M.

  Here, the start time ts of the fuel reformer and the complete stop time te of the fuel reformer are required per day by integrating H0 (t) corresponding to the power demand W0 (t) with time t. The total hydrogen amount H0t can be calculated.

However, the time from the starting time ts of the fuel reformer to the steady operation is approximated to 0, and the time from the start of stopping the fuel reformer to the complete stop time te of the fuel reformer is also 0. Approximate.
In such a case, H00 can be calculated from the following equation.

H00 × (te−ts) = H00 × t0 = H00t = Cs × H0t Equation (3)
(4) A hydrogen amount H00 is calculated so as to satisfy Expression (2), and stored in the memory M.
<Operational stage>
(5) When the fuel reformer start-up time ts is reached, the fuel reformer start-up is started, and the hydrogen amount H00 is generated so as to satisfy Equation (2) by the steady operation of the fuel reformer. The fuel cell stack covers the power demand and stores hydrogen in the hydrogen storage device.
(6) When te = ts + to when the fuel reformer is completely stopped, the operation of the fuel reformer is completely stopped.
(7) Between the time te when the fuel reformer is completely stopped and the start time ts when the next fuel reformer is started, the power demand is covered by hydrogen stored in the hydrogen storage device.
(8) Hereinafter, the procedures (5) to (7) are repeated.
here,
H = H (W) = (W / η (W)) / C (1)
H00t = Cs × H0t (2)
W0 (t): Assumed power demand H0 (t) at time t obtained from an assumed power demand curve that is a function of time t: From an assumed hydrogen quantity curve required to generate the assumed power demand W0 (t) Calculated by substituting W = W0 (t) into Equation (1) for the estimated hydrogen amount at the time t obtained.
η (W): power generation efficiency when power load W is generated by the fuel cell stack, power generation efficiency calculated in advance as a function of power load W C: heat generation amount of hydrogen per unit volume H0t: H0 (t) Total estimated hydrogen amount H00t for one day obtained by integrating at time t: Total hydrogen amount generated between the time ts when the fuel reformer is started and the time te = ts + to when it is stopped,
Cs: Safety factor of 1 or more ○ Memory M is a storage device installed in the control device.
A fuel cell stack is the heart of a fuel cell power generation system that generates electricity by electrochemically reacting hydrogen generated in a fuel reformer and oxygen in the air.
A fuel reformer refers to an apparatus for producing a gas containing hydrogen as a main component (hereinafter also simply referred to as hydrogen) using a fuel such as city gas, naphtha or methanol as a raw material. Generally, it refers to an apparatus for reforming fuel and steam to produce a gas containing hydrogen as a main component (reformed gas), and the reforming method in this case is referred to as a steam reforming method.
The bypass pipe is a pipe that is reconnected after branching from the middle of the hydrogen pipe that supplies hydrogen generated in the fuel reformer to the fuel cell stack, and a hydrogen storage device is provided in the middle of the bypass pipe.
○ Branch piping is piping that branches directly from the middle of the hydrogen piping that supplies hydrogen generated in the fuel reformer to the fuel cell stack, and then is directly connected to the fuel cell stack. A hydrogen storage device is installed in the middle of the branch piping. Provide.
The hydrogen storage device refers to a device that can store hydrogen, and examples thereof include a device incorporating a pressure cylinder, a hydrogen storage alloy, and the like.

For example, in the case of a pressure cylinder, an upper limit pressure and a lower limit pressure are set in advance, and the fuel cell power generation system is controlled so that the reformer is stopped when the storage device pressure exceeds the upper limit pressure. Conversely, when the storage device pressure falls below the lower limit pressure and the reformer is not in operation, the fuel cell power generation system is controlled to start the reformer.
A fuel is a fuel supplied to a fuel reformer, and examples thereof include city gas, naphtha, or methanol.
○ Electric load refers to electric appliances that consume electric power. The power load is normally alternating current, but direct current is also conceivable. When using commercially available AC equipment for lighting equipment, AV equipment, kitchen equipment, air-conditioning equipment, etc. used for power loads, the DC power generated by the fuel cell power generation system is converted into AC power by an inverter and supplied to the power load. Is done. When the power load is direct current, the direct current power is supplied to the power load as it is.
○ Power demand refers to the amount of power consumed by customers due to power load. Here, the power demand amount generally refers to the amount of energy consumed per unit time, but may also refer to the amount of energy consumed in a certain time zone.
○ Waste heat recovery device refers to a device that recovers the heat discharged from the fuel cell stack or fuel reformer during power generation and effectively uses it as energy for air conditioning or hot water supply. The exhaust heat recovery device includes an absorption refrigerator and a hot water boiler, and air conditioning can be performed using cold water obtained by the absorption refrigerator and hot water obtained by the hot water boiler. In such a case, exhaust heat recovery is performed by an absorption refrigerator during a period in which cooling is required, and the cold water obtained here is used for cooling. Also, during the period when heating is required, exhaust heat recovery is performed with a hot water boiler, and the hot water obtained here is used for heating. As a result, the power load used for air-conditioning equipment and the like becomes small, such as a cold / hot water feed pump and a ventilation fan. The exhaust gas from the absorption chiller and the hot water boiler can be further recovered by a hot water heater.
[Explanation of symbols]
○ W0 (t): Assumed power demand at time t obtained from an assumed power demand curve that is a function of time t Note that W0 (t) is an aggregate of points in the assumed power demand curve that is a function of time t. Can be.
○ H0 (t): The assumed hydrogen amount at time t obtained from the assumed hydrogen amount curve necessary for generating the estimated power demand W0 (t), and substituting W = W0 (t) into Equation (1) calculate.

Note that W0 (t) may be an aggregate of points in an assumed power demand curve that is a function of time t.
○ η (W): power generation efficiency when the power load W is generated by the fuel cell stack, and power generation efficiency calculated in advance as a function of the power load W ○ H0t: total assumed hydrogen amount during one day, assumed hydrogen amount The curve H0 (t) is calculated by integrating per day at time t.
○ H00t: Total amount of hydrogen generated between ts when starting the fuel reformer and te = ts + to when stopping
○ Cs: A design factor with a safety factor of 1 or more, set in advance.
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The present invention is the invention described in the claims, and specifically, is the following invention.

  The combined heat and power system is classified according to the energy storage type. (1) A combined heat and power system (hereinafter referred to as a battery type) including a battery for storing electric energy and (2) a hydrogen storage device for storing hydrogen. There is a combined heat and power system (hereinafter referred to as a hydrogen storage type).

  In both cases, it was considered by those skilled in the art that the peak of daily fluctuations in power demand was cut, and the entire combined heat and power system could be made compact.

  However, the inventor paid attention to the fact that the fuel reformer and fuel cell stack can be made compact in the former, but the fuel reformer can be made compact in the latter, but the fuel cell stack cannot be made compact. Thus, the present invention has been completed with the idea that the demerit that the fuel cell stack cannot be made compact can exhibit another advantage different from the compact design.

That is, by grasping the facts of the common points and differences between the above battery type and the hydrogen storage type, unless you get the idea that the hydrogen storage type cannot compensate for the disadvantage that the fuel cell stack cannot be made compact with another advantage, It can be said that the birth of the present invention was not possible.
[Claim 1] A fuel cell stack that generates electricity by supplying hydrogen and oxygen, a fuel reformer that generates hydrogen by supplying fuel, and hydrogen that supplies hydrogen generated in the fuel reformer to the fuel cell stack A hydrogen storage device is installed in the middle of the piping, the air piping that supplies oxygen in the air to the fuel cell stack, and the bypass piping that is reconnected after branching from the middle of the hydrogen piping. In the fuel cell power generation system which starts the massifier only once, stops for a certain period of time and then stops completely, when the fuel reformer starts to start, the fuel reformer starts to start and the fuel The steady operation of the reformer generates the hydrogen amount H00 so as to satisfy the formula (2), covers the power demand by the fuel cell stack, stores the hydrogen in the hydrogen storage device, and then reforms the fuel. At the time of complete stop te = ts + to, the operation of the fuel reformer is completely stopped, and the electric power demand is from the complete stop time te of the fuel reformer to the next start time ts of the fuel reformer. A fuel cell power generation system comprising: a control device that controls the hydrogen storage device to cover with hydrogen stored in the hydrogen storage device.
A fuel cell power generation system.
here,
H = H (W) = (W / η (W)) / C (1)
H00t = Cs × H0t (2)
W0 (t): Assumed power demand H0 (t) at time t obtained from an assumed power demand curve that is a function of time t: From an assumed hydrogen quantity curve required to generate the assumed power demand W0 (t) Calculated by substituting W = W0 (t) into Equation (1) for the estimated hydrogen amount at the time t obtained.
η (W): power generation efficiency when power load W is generated by the fuel cell stack, power generation efficiency calculated in advance as a function of power load W C: heat generation amount of hydrogen per unit volume H0t: H0 (t) Total estimated hydrogen amount H00t for one day obtained by integrating at time t: Total hydrogen amount generated between the time ts when the fuel reformer is started and the time te = ts + to when it is stopped,
Cs: safety factor of 1 or more ---------------------------------
The present invention is an invention corresponding to the fuel cell power generation system of one embodiment of FIG.

  The structural feature of the present invention is that a hydrogen storage device is installed in the middle of a bypass pipe that is reconnected after branching from the middle of the hydrogen pipe.

  The control method is complicated and expensive, such as the need for a synchronous input device for AC power confluence, whereas hydrogen gas confluence can be performed only by operating the valve, so handling of the device is very Easy to be.

  Furthermore, the control feature of the present invention is that in a fuel cell power generation system that starts the fuel reformer only once during a day, and after it has been steadily operated for a certain period of time, it completely stops. When the start-up time ts is reached, the fuel reformer starts to start, and the hydrogen amount H00 is generated so as to satisfy the formula (2) by the steady operation of the fuel reformer, and the electric power demand is generated by the fuel cell stack. After the hydrogen is stored in the hydrogen storage device, the operation of the fuel reformer is completely stopped at the time te = ts + to when the fuel reformer is completely stopped. During the start time ts of the next start of the fuel reformer, the control unit is configured to control the electric power demand so as to be covered with hydrogen stored in the hydrogen storage device.

  By controlling the system as described above, it becomes possible to limit the operation of the fuel reformer to a range of efficient hydrogen generation amount. Further, by storing hydrogen in a state where it can be taken out at any time, it becomes possible to supply hydrogen exceeding the hydrogen production capacity of the fuel reformer to the fuel cell stack, and the capacity of the fuel reformer can be reduced.

As a result, the energy efficiency of the entire system is improved, the fuel reformer capacity is reduced, and a fuel cell power generation system and a fuel cell power generation method including an inexpensive, compact and highly efficient hydrogen storage device are provided. The object of the invention can be achieved.
[Claim 2] A fuel cell stack that generates electricity by supplying hydrogen and oxygen, a fuel reformer that generates hydrogen by supplying fuel, and hydrogen that supplies hydrogen generated in the fuel reformer to the fuel cell stack Piping, an air pipe that supplies oxygen in the air to the fuel cell stack, and a hydrogen storage device installed in the middle of the branch pipe that branches directly from the hydrogen pipe and then directly connects to the fuel cell stack. In the fuel cell power generation system that starts the fuel reformer only once, stops the fuel reformer for a certain period of time, and then stops completely, when the fuel reformer starts to start, the fuel reformer is started. Start and generate a hydrogen amount H00 to satisfy Equation (2) by steady operation of the fuel reformer, cover the power demand by the fuel cell stack, and store hydrogen in the hydrogen storage device After that, at the time te = ts + to when the fuel reformer is completely stopped, the operation of the fuel reformer is completely stopped. From the time te when the fuel reformer is completely stopped, the start time ts of the next fuel reformer is started. The fuel cell power generation system is characterized by comprising a control device that controls the power demand to be covered by the stored hydrogen stored in the hydrogen storage device.
here,
H = H (W) = (W / η (W)) / C (1)
H00t = Cs × H0t (2)
W0 (t): Assumed power demand H0 (t) at time t obtained from an assumed power demand curve that is a function of time t: From an assumed hydrogen quantity curve required to generate the assumed power demand W0 (t) Calculated by substituting W = W0 (t) into Equation (1) for the estimated hydrogen amount at the time t obtained.
η (W): power generation efficiency when power load W is generated by the fuel cell stack, power generation efficiency calculated in advance as a function of power load W C: heat generation amount of hydrogen per unit volume H0t: H0 (t) Total estimated hydrogen amount H00t for one day obtained by integrating at time t: Total hydrogen amount generated between the time ts when the fuel reformer is started and the time te = ts + to when it is stopped,
Cs: safety factor of 1 or more ---------------------------------
The present invention corresponds to the fuel cell power generation system of the second embodiment shown in FIG.
A feature of the present invention is that a hydrogen storage device is installed in the middle of the branch pipe that branches from the middle of the hydrogen pipe and is directly connected to the fuel cell stack.
Others are the same as those described in the first aspect of the invention.
[Claim 3] A fuel cell stack that generates electricity by supplying hydrogen and oxygen, a fuel reformer that generates hydrogen by supplying fuel, and hydrogen that supplies hydrogen generated in the fuel reformer to the fuel cell stack Piping, air piping for supplying oxygen in the air to the fuel cell stack, and a hydrogen storage device in the middle of the hydrogen piping, starting the fuel reformer only once during the day, In the fuel cell power generation system that stops completely after steady operation, when the start time ts of the fuel reformer is reached, the start of the fuel reformer is started, and the formula (2) is calculated by the steady operation of the fuel reformer. A hydrogen amount H00 is generated so as to satisfy the demand, and the fuel cell stack covers the power demand, and after storing hydrogen in the hydrogen storage device, the fuel reformer is operated when the fuel reformer is completely stopped te = ts + to. The operation of the mass device is completely stopped, and the stored hydrogen stored in the hydrogen storage device is stored in the hydrogen storage device during the time ts from the time when the fuel reformer is completely stopped to the time when the next fuel reformer is started. A fuel cell power generation system comprising a control device that performs control so as to cover the vehicle.
here,
H = H (W) = (W / η (W)) / C (1)
H00t = Cs × H0t (2)
W0 (t): Assumed power demand H0 (t) at time t obtained from an assumed power demand curve that is a function of time t: From an assumed hydrogen quantity curve required to generate the assumed power demand W0 (t) Calculated by substituting W = W0 (t) into Equation (1) for the estimated hydrogen amount at the time t obtained.
η (W): power generation efficiency when power load W is generated by the fuel cell stack, power generation efficiency calculated in advance as a function of power load W C: heat generation amount of hydrogen per unit volume H0t: H0 (t) Total estimated hydrogen amount H00t for one day obtained by integrating at time t: Total hydrogen amount generated between the time ts when the fuel reformer is started and the time te = ts + to when it is stopped,
Cs: safety factor of 1 or more ---------------------------------
The present invention corresponds to the fuel cell power generation system of the third embodiment of FIG.
A feature of the present invention is that a hydrogen storage device is installed in the middle of the hydrogen pipe.
Since the hydrogen storage device is provided in the middle of the hydrogen pipe as in the configuration of the present invention, the components of the compressor and the valve are reduced, the cost can be reduced, and the operation method of the fuel cell power generation system is claimed in claim 1. It is simpler than the described invention, and is less likely to fail.
Others are the same as those described in the first aspect of the invention.
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[Claim 4] When the hydrogen pressure of the hydrogen storage device is measured and the equation (3) is provided, the operation of the fuel reformer is stopped. When the equation (4) is provided, the fuel reformer is in operation. The fuel cell power generation system according to any one of claims 1 to 3, wherein the fuel reformer is started when the fuel reformer is not in operation.
here,
PH> PC1 ··· Formula (3)
PH <PC2 ··· Equation (4)
PH: hydrogen pressure of hydrogen storage device PC1: upper limit value of hydrogen pressure of hydrogen storage device PC2: lower limit value of hydrogen pressure of hydrogen storage device ------------------- ---------------
The invention according to claim 4 (the present invention) measures the hydrogen pressure of the hydrogen storage device, and when the hydrogen pressure PH of the hydrogen storage device satisfies either the formula (3) or the formula (4), The invention is characterized in that the operation of the fuel reformer is stopped and the start of the fuel reformer is started in an unsteady mode other than the operation modes described in 1 to 3 (defined as a steady mode in the present application). is there.
The operation in the steady mode and the operation in the unsteady mode will be described below with reference to FIG. 7 or FIG. 8 in order to clarify the difference between them.
FIG. 7 is an operation flowchart of the fuel cell system according to the embodiment of the present invention. FIG. 8 is an operation flowchart (details) of the fuel cell system according to the embodiment of the present invention.
<Step 1>
In step 1, a constant power demand curve W0 (t) that is a function of time t is predicted, and the value is stored in the memory M in advance for each time.
In practice, for example, t1 = 0, t2 = Δt... Tn = (n−1) Δt, and the corresponding W0 (t1), W0 (t2) t... W0 (tn) are stored in the memory M in advance. . When obtaining the function W0 (t) at an arbitrary time t, it is calculated by interpolation.
<Step 2>
In step 2, the total hydrogen amount H00t generated between the start time ts of the fuel reformer and the stop time te = ts + to is calculated.
The total amount of hydrogen H00t is calculated by using the formula (1), the formula (1 ′) ′, and the formula (2).
<Step 3>
In step 3, the time to from the start time ts to the stop time te can be obtained by dividing the hydrogen amount H00t by the rated value of the hydrogen generation amount of the fuel reformer.
If either the starting time ts or the stopping time te is determined, the starting time ts and the stopping time te are automatically determined, and the steady operation mode of the fuel cell power generation system is determined. Furthermore, it is desirable to confirm that there is no problem by simulating driving.
<Step S>
In step S, when the time t reaches the time ts, the start of the fuel reformer is started.
<Step 4>
In step 4, the hydrogen pressure PH of the hydrogen storage device is measured.
<Step 5>
In step 5, it is determined whether or not equation (3) is provided.
PH> PC1 ··· Formula (3)
When the mathematical formula (3) is included, the routine mode operation is canceled, and the process proceeds to <Step 9> to stop the fuel reformer.
<Step 6>
In step 6, it is determined whether or not equation (4) is provided.
PH <PC2 ··· Equation (4)
When the mathematical formula (4) is provided, the routine mode operation is canceled and the process proceeds to <Step 7>.
<Step 7>
In Step 7, it is determined whether or not the fuel reformer is in operation. If not, the process proceeds to <Step 8> to start the fuel reformer.
<Step 8>
In step 8, the fuel reformer is started.
<Step E>
In step E, when the time t reaches te, the operation of the fuel reformer is stopped.

  In the steady operation mode, the fuel reformer starts to be started in step S after steps 1 to 3.

  In Step 4, the hydrogen pressure PH of the hydrogen storage device is continuously measured, but in Steps 5 to 6, Equation (3) and Equation (4) are not provided, and the operation of the fuel reformer is stopped when time t reaches te. Will do.

That is, in the steady operation mode, the flow is a simple flow that moves from step 1 to step E to step E.
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[Claim 5] The fuel cell power generation system according to any one of claims 1 to 3, further comprising an exhaust heat recovery device that recovers exhaust heat from the fuel cell stack.

The present invention further improves the energy efficiency of the fuel cell power generation system.
[Claim 6] The fuel cell power generation system according to claims 1 to 4, wherein the hydrogen storage device is a pressure cylinder.

According to the present invention, it is clarified that hydrogen is pressure-stored in a pressure cylinder.
[Claim 7] The fuel cell power generation system according to any one of claims 1 to 5, wherein when the hydrogen storage device is a pressure cylinder, hydrogen is stored in the pressure cylinder using nighttime electric power.

According to the present invention, by using the nighttime power of the fuel cell power generation system, it is possible to store the surplus power of the power company at night and to release the power at the peak of the daytime, thereby leveling the commercial power.
[Claim 8] The fuel cell power generation system according to any one of claims 1 to 7, further comprising a power capacitor.

According to the present invention, it is possible to cope with instantaneous power demand such as inrush power.
[Claim 9] The fuel reformer is operated for a certain period of time after the end of business on Friday, the necessary hydrogen amount is stored in the hydrogen storage device between Saturday and Sunday, the fuel reformer is stopped, and the fuel reforming is performed. After stopping the reactor, the amount of hydrogen from the hydrogen storage device is supplied to the fuel cell stack to cover the power consumption of the power load W, and the fuel reformer is operated for a certain period before the start of business on Monday of the beginning of the week. The fuel cell power generation system according to claim 1, wherein:

  When the power switch of the power load is turned on, the inrush power increases. The power capacitor is provided in order to cope with a rapid fluctuation of the power load.

In the present invention,
[Claim 10] A fuel cell stack that generates electricity by supplying hydrogen and oxygen, a fuel reformer that generates hydrogen by supplying fuel, and hydrogen that supplies hydrogen generated in the fuel reformer to the fuel cell stack A hydrogen storage device is installed in the middle of the piping, the air piping that supplies oxygen in the air to the fuel cell stack, and the bypass piping that is reconnected after branching from the middle of the hydrogen piping. In the fuel cell power generation system which starts the massifier only once, stops for a certain period of time and then stops completely, when the fuel reformer starts to start, the fuel reformer starts to start and the fuel By generating a hydrogen amount H00 to satisfy Equation (2) through steady operation of the reformer, the fuel cell stack covers the power demand, and the hydrogen is stored in the hydrogen storage device. At the time of complete stop te = ts + to, the operation of the fuel reformer is completely stopped, and the power demand is reduced from the fuel reformer complete stop time te to the next start time ts of the fuel reformer. A fuel cell power generation method characterized by covering with hydrogen stored in a hydrogen storage device.
here,
H = H (W) = (W / η (W)) / C (1)
H00t = Cs × H0t (2)
W0 (t): Assumed power demand H0 (t) at time t obtained from an assumed power demand curve that is a function of time t: From an assumed hydrogen quantity curve required to generate the assumed power demand W0 (t) Calculated by substituting W = W0 (t) into Equation (1) for the estimated hydrogen amount at the time t obtained.
η (W): power generation efficiency when power load W is generated by the fuel cell stack, power generation efficiency calculated in advance as a function of power load W C: heat generation amount of hydrogen per unit volume H0t: H0 (t) Total estimated hydrogen amount H00t for one day obtained by integrating at time t: Total hydrogen amount generated between the time ts when the fuel reformer is started and the time te = ts + to when it is stopped,
Cs: safety factor of 1 or more ---------------------------------
The present invention is a fuel cell power generation method invention corresponding to the invention of claim 1, 2, or 3 (fuel cell power generation system). Matters not described here are the same as those described in the first, second, or third aspect of the present invention.

  In the present invention, the configuration of bypass piping, branch piping, and the like is not limited. The present invention provides a fuel reformer in a fuel cell power generation system in which a hydrogen storage device is installed to start a fuel reformer only once during a day, and to stop after a certain period of time to steady operation. When the starting time ts of the fuel cell is reached, the start of the fuel reformer is started, the hydrogen amount H00 is generated so as to satisfy Equation (2) by steady operation of the fuel reformer, and the fuel cell stack generates power. After supplying the demand and storing hydrogen in the hydrogen storage device, when the fuel reformer is completely stopped te = ts + to, the operation of the fuel reformer is completely stopped. During the next start time ts of the fuel reformer, the electric power demand is covered with hydrogen stored in the hydrogen storage device.

  Such a characteristic configuration makes it possible to perform the operation of the fuel reformer by limiting it to a range of efficient hydrogen generation amount. Further, by storing hydrogen in a state where it can be taken out at any time, it becomes possible to supply hydrogen exceeding the hydrogen production capacity of the fuel reformer to the fuel cell stack, and the capacity of the fuel reformer can be reduced.

  Accordingly, it is an object of the present invention to provide a fuel cell power generation system and a fuel cell power generation method provided with an inexpensive and compact hydrogen storage device while improving the energy efficiency of the entire system and reducing the capacity of the fuel reformer. Can be achieved.

The present invention is a fuel cell power generation method invention corresponding to the superordinate concept of the invention of claim 1, 2, or 3 (fuel cell power generation system). Matters not described here are the same as those described in the first, second, or third aspect of the present invention.

[10] The fuel cell power generation system according to [9], wherein the hydrogen storage device is a hydrogen storage device in the middle of a bypass pipe to be reconnected after branching from the middle of the hydrogen pipe.

  The present invention is a fuel cell power generation method invention corresponding to the invention according to claim 1 (fuel cell power generation system). Matters not described here are the same as those described in the first aspect of the present invention.

[Claim 1 1 ] The fuel cell power generation method, wherein the hydrogen storage device is a hydrogen storage device installed in the middle of a branch pipe directly connected to the fuel cell stack.
The present invention is a fuel cell power generation method invention corresponding to the invention according to claim 2 (fuel cell power generation system). The matters not described here are the same as those described in the second aspect of the present invention.
[Claim 1 2] hydrogen storage device, a fuel cell power generation system which is a hydrogen storage device installed in the middle of the hydrogen piping.
The present invention is a fuel cell power generation method invention corresponding to the invention described in claim 3 (fuel cell power generation system). Matters not described here are the same as those described in the third aspect of the present invention.
[Claim 1 3] In addition, to measure the hydrogen pressure in the hydrogen storage device, when having a formula (3), stops the operation of the fuel reformer, if having a formula (4), a fuel reformer The fuel cell power generation method according to any one of claims 10 to 12 , wherein it is determined whether or not the fuel reformer is in operation, and if it is not in operation, the fuel reformer is started.
here,
PH> PC1 ··· Formula (3)
PH <PC2 ··· Equation (4)
PH: Hydrogen pressure of hydrogen storage device PC1: Upper limit value of hydrogen pressure of hydrogen storage device PC2: Lower limit value of hydrogen pressure of hydrogen storage device The present invention is a fuel cell corresponding to the invention according to claim 4 (fuel cell power generation system) It is an invention of a power generation method. The matters not described here are the same as those described in the fourth aspect of the present invention.
[Claim 1 4] The fuel cell power generation method according to claim 10 to 1 3, wherein further comprising a heat recovery device for recovering exhaust heat from the fuel cell stack.
The present invention is a fuel cell power generation method invention corresponding to the invention according to claim 5 (fuel cell power generation system). For matters not described here, the same as the description contents of claim 5, wherein INVENTION claim 1 5] The fuel cell power generation according to claim 10 to 1 4, wherein the hydrogen storage device, characterized in that the pressure cylinder Method.
The present invention is a fuel cell power generation method invention corresponding to the sixth aspect of the invention (fuel cell power generation system). The matters not described here are the same as those described in the invention described in claim 6. [Claim 16 ] When the hydrogen storage device is a pressure cylinder, hydrogen is stored in the pressure cylinder using nighttime power. fuel cell power generation method according to claim 10 to 1 5 wherein the.
The present invention is a fuel cell power generation method invention corresponding to the seventh aspect of the invention (fuel cell power generation system).
[Claim 17 ] The fuel cell power generation method according to any one of claims 10 to 16 , further comprising a power capacitor.
The present invention is a fuel cell power generation method invention corresponding to the invention according to claim 8 (fuel cell power generation system).
[Claim 18 ] The fuel reformer is operated for a certain period of time after the end of business on Friday, the required hydrogen amount is stored in the hydrogen storage device between Saturday and Sunday, the fuel reformer is stopped, and the fuel reformer is stopped. After shutting down the device, supply the amount of hydrogen H from the hydrogen storage device to the fuel cell stack to cover the power consumption of the power load W, and operate the fuel reformer from a certain period before the start of business on Monday morning fuel cell power generation method according to claim 10 to 1 7, wherein the performing.
The present invention is a fuel cell power generation method invention corresponding to the ninth aspect of the invention (fuel cell power generation system). The matters not described here are the same as those described in the ninth aspect of the invention.

As described above, according to the configuration of the present invention, all the problems of the present invention can be sufficiently achieved. That is, when the power consumption is low and the hydrogen production capacity of the fuel reformer is sufficient, hydrogen is stored in the hydrogen storage device, and the power consumption increases and the hydrogen production capacity of the fuel reformer is insufficient. Occasionally, hydrogen stored in the hydrogen storage device compensates for the shortage of hydrogen production capacity, eliminating the need for a fuel reformer corresponding to the maximum power demand, making the system more compact, reducing capital investment, and fuel It is possible to reduce the fuel during the warm-up operation of the reformer, and it is possible to operate the fuel reformer only within the range of efficient hydrogen generation amount, and the energy efficiency of the entire fuel cell power generation system Can be improved.

  By installing the exhaust heat recovery device, the exhaust heat of the fuel cell stack and the fuel reformer can be used effectively.

  By driving the compressor with nighttime power and compressing and storing hydrogen in a pressure cylinder, it becomes possible to store power similar to that of pumped storage power generation, and it is possible to cut the system power peak during the daytime.

  In particular, when a fuel cell power generation system (simply called the former) having a power storage device such as a storage battery is compared with a fuel cell power generation system of the present invention (invention) having a hydrogen storage device, There are significant effects that cannot be predicted by those skilled in the art.

  The former has the advantage that the capacity of the fuel reformer can be made more compact than that of the fuel reformer of the present invention because the amount of hydrogen generated in the fuel reformer and the hydrogen is used to generate power by the fuel cell stack.

  Although the present invention is inferior in compactness, the power generation efficiency of the fuel cell stack has a characteristic that the low load operation is higher as shown in FIG.

  In the former case, since the emphasis is placed on the compact design of the fuel reformer and the fuel cell stack, the power generation efficiency of the fuel cell stack is higher than that of the present invention. It must be inferior.

  As a result of designing the system of both the former and the present invention, the inventor first noticed the following.

That is, in the present invention, the fuel reformer can be made compact in the same manner as the former of the battery type, but the fuel cell stack is disadvantageous in that the design capacity must be increased compared to the former. . However, paying attention to the power generation efficiency of the fuel cell stack, it has been found that the power generation efficiency of the fuel cell stack is higher than that of the former in the present invention as described below.
When the operation method of starting and stopping the hydrogen storage type fuel cell system once a day as in the present invention is adopted, it is unavoidable to have a considerably low load operation (this is a disadvantage in terms of rated operation). However, it is because the power generation efficiency of the fuel cell stack is higher in the low-load operation, as is apparent from FIG.

  As described above, the present invention is inferior in size to the fuel cell stack compared to the former, but conversely, when the operation method of starting and stopping the fuel cell system once a day is adopted, It was forced to perform low load operation for a considerable period of time, and this exerted a remarkable effect that could not be predicted by those skilled in the art that this would work in reverse and increase the power generation efficiency of the fuel cell stack.

  A fuel cell stack that generates electricity by supplying hydrogen and oxygen, a fuel reformer that generates hydrogen by supplying fuel, a hydrogen pipe that supplies hydrogen generated in the fuel reformer to the fuel cell stack, In a fuel cell power generation system in which a hydrogen storage device is provided in the middle of the air piping for supplying oxygen to the fuel cell stack and in the hydrogen piping, in order to cover the power demand for the amount of hydrogen generated in the fuel reformer When the amount of hydrogen consumed by the fuel cell stack is small and there is surplus hydrogen, the surplus hydrogen is stored in the hydrogen storage device, and the fuel cell stack is used to cover the power demand for the amount of hydrogen generated by the fuel reformer. A fuel cell power generation system comprising a control device that controls the system to compensate for the shortage of hydrogen that has been stored when the amount of hydrogen consumed by the fuel is large It is.

Example 1 will be described below. FIG. 1 is a block diagram showing an embodiment of a fuel cell power generation system 100 according to the present invention.
A fuel cell stack 3 that generates electricity by supplying hydrogen and oxygen, a fuel reformer 1 that generates hydrogen by supplying fuel F, and hydrogen H generated in the fuel reformer 1 is supplied to the fuel cell stack 3 A hydrogen pipe LH, an air pipe LA for supplying oxygen in the air A to the fuel cell stack 3, a hydrogen storage device 2 provided in the middle of a bypass pipe LBP that is reconnected after branching from the middle of the hydrogen pipe LH, And a control device (not shown).
Then, the control device starts starting the fuel reformer 1 in the fuel cell power generation system 100 that starts starting the fuel reformer 1 only once during a day, stops the fuel reformer 1 for a certain period of time, and then stops completely. At time ts, the fuel reformer 1 starts to be started, and the hydrogen amount H00 is generated by the steady operation of the fuel reformer 1 so as to satisfy Equation (2). After supplying the demand and storing hydrogen in the hydrogen storage device 2, the operation of the fuel reformer 1 is completely stopped at the time te = ts + to when the fuel reformer 1 is completely stopped. From the complete stop time te to the next start time ts of the fuel reformer 1, the electric power demand is controlled to be covered by the hydrogen stored in the hydrogen storage device 2.
As a result, the fuel reformer 1 can be operated steadily by limiting it to a high efficiency range, and the energy efficiency is improved more than before.
On the other hand, by storing hydrogen in the hydrogen storage device 2 in a state where it can be taken out at any time, a large-capacity fuel reformer 1 that covers the maximum amount of hydrogen in the fuel cell stack 3 is not required, making the system compact, reducing capital investment, The fuel F required during the warm-up operation of the fuel reformer 1 can be reduced.
Due to the above effects, the fuel cell power generation system 100 including the hydrogen storage device 2 that is compact, inexpensive, and highly efficient can be realized.
Hereinafter, the first embodiment will be described in detail with reference to FIG. FIG. 1 is a block diagram showing an embodiment of a fuel cell power generation system 100 according to the present invention.
The fuel cell power generation system 100 includes a fuel reformer 1, a hydrogen storage device 2, a fuel cell stack 3, and a control device (not shown). Further, the exhaust heat recovery device 4 is also a component. The power generated by the fuel cell power generation system 100 is supplied to the power load 11 through the power line LEP.
The fuel reformer 1 generates hydrogen rich gas (hydrogen) using the fuel F as a raw material.
The fuel reformer 1 is connected to the fuel cell stack 3 through a hydrogen pipe LH. A compressor C2 and a valve V2 are provided in the middle of the hydrogen pipe LH. A bypass pipe LBP branched from an upstream point of the compressor is provided, and a compressor C1, a valve V1, a hydrogen storage device 2, and a valve V3 are sequentially provided in the middle of the bypass pipe LBP.
《Fuel cell power generation method (weekday operation mode)》
Hereinafter, the fuel cell power generation method (weekday operation mode) will be described with reference to FIG. 7 or FIG.
<Starting method of fuel reformer 1>
A control device (not shown) activates the fuel reformer 1 only once during a day. When the start time ts of the fuel reformer 1 is reached, the control device starts the fuel reformer 1 and performs steady operation of the fuel reformer 1.
Here, the activation start time ts is set in advance and stored in the memory M.
<Fuel reformer steady operation method>
A control device (not shown) generates a hydrogen amount H00 so as to satisfy Equation (2), covers the power demand by the fuel cell stack, stores hydrogen in the hydrogen storage device 2, and then changes the fuel. At the time te = ts + to when the mass device 1 is completely stopped, the operation of the fuel reformer 1 is completely stopped, and from the time te when the fuel reformer 1 is completely stopped to the time ts when starting the next fuel reformer 1 Controls the power demand to be covered by the hydrogen stored in the hydrogen storage device 2.

  Hereinafter, the steady operation method of the fuel reformer 1 of this system will be described in detail.

This will be described with reference to FIG. The contents not described below are the same as those described in the first embodiment.
When the starting time ts of the fuel reformer 1 is reached, the control device automatically starts the fuel reformer 1 and performs a steady operation at a constant output H00 (reformed hydrogen amount of the fuel reformer 1). .

  Here, the constant output H00 information is a numerical value set in advance and is stored in the memory M.

  The control apparatus performs the following control using the constant output H00 information.

  The fuel reformer 1 produces hydrogen with a steady hydrogen generation amount H00. However, H00 = 0 between the complete stop time te and the start time ts of the fuel reformer 1.

The hydrogen amount H0 (t) stored in advance for the hydrogen amount H0 (t) corresponding to the assumed power demand W0 (t) at time t is compared with the hydrogen amount H00 actually produced by the fuel reformer 1.
Cases are divided into three cases.

That is,
(1) In the case of H0 (t)> H00 (2) In the case of H0 (t) = H00 (3) In the case of H0 (t) <H00, the control method by the control device will be described below.
<In the case of H0 (t)>H00>
<In the case of H0 (t) <H00 (when hydrogen H remains)>
When the amount of hydrogen H (t) consumed by the fuel cell stack 3 is small in order to cover the power consumption of the power load 11 with respect to the amount of hydrogen H (t) generated in the fuel reformer 1, the fuel reforming is performed. Of the hydrogen produced by the mass device 1, the surplus hydrogen is opened by the valve V1 and the valve V3 is closed, and the pressure is increased by the compressor C1, and is stored in the hydrogen storage device 2 through the bypass pipe LBP. Hydrogen necessary for power generation is boosted by the compressor C2 after opening the valve V2, and supplied to the fuel cell stack 3 through the hydrogen pipe LH. On the other hand, the air A is also pressurized by the compressor C4 and supplied to the fuel cell stack 3 through the air pipe LA as much as necessary for power generation.
<When H0 (t) = H00>
When the hydrogen amount H (t) generated in the fuel reformer 1 and the estimated required hydrogen amount H0 (t) corresponding to the assumed power demand W0 (t) are the same, the hydrogen generated in the fuel reformer 1 is a valve After V2 is opened, the pressure is increased by the compressor C2 and supplied to the fuel cell stack 3 through the hydrogen pipe LH without excess or deficiency. On the other hand, the air A is also pressurized by the compressor C4 and supplied to the fuel cell stack 3 through the air pipe LA as much as necessary for power generation.
<H0 (t)> H00 (when hydrogen H is insufficient)>
When the estimated required hydrogen amount H0 (t) corresponding to the estimated power demand W0 (t) is greater than H00 and the hydrogen is insufficient with respect to the hydrogen amount H (t) generated in the fuel reformer 1, the fuel reforming All the hydrogen produced in the vessel 1 is pressurized by the compressor C2 with the valve V2 opened, and supplied to the fuel cell stack 3 through the hydrogen pipe LH. The shortage of hydrogen is supplied by closing C1 and then opening V3 to join the hydrogen stored in the hydrogen storage device 2 to the hydrogen pipe LH through the bypass pipe LBP. On the other hand, the air A is also pressurized by the compressor C4 and supplied to the fuel cell stack 3 through the air pipe LA as much as necessary for power generation.

  The DC power generated in the fuel cell stack 3 is converted into AC power via an inverter (not shown) installed in the middle of the power line LE and supplied to the power load 11. Further, the exhaust heat generated from the fuel cell stack 3 is recovered by the exhaust heat recovery device 4 and supplied to the heat load 12.

As a result, the fuel reformer 1 can be operated only within the range of the efficient hydrogen generation amount. In addition, by providing the hydrogen storage device 2, it is possible to meet the demand for hydrogen in the fuel cell stack 3 that exceeds the hydrogen production capacity of the fuel reformer 1, and the capacity of the fuel reformer 1 can be reduced. .
《Fuel cell power generation method (holiday operation mode)》
An operation method (holiday operation mode) of the fuel cell power generation system 100 when the fuel reformer 1 is stopped on a weekend (Saturday / Sunday) will be described.
This will be described with reference to FIG.
During the weekend (Saturday / Sunday), when the power consumption of the power load 11 is low, the fuel reformer 1 is stopped and the power stored during the weekend (Saturday / Sunday) with the hydrogen stored in the hydrogen storage device 2 11 power consumption may be covered.
For example, the business is closed on Friday at 19:00. The fuel reformer 1 is operated for a certain period of time after the end of business, the necessary hydrogen is stored in the hydrogen storage device 2 during the weekend (Saturday and Sunday), and the fuel reformer 1 is completely stopped at time te. After stopping the fuel reformer 1, the hydrogen stored in the hydrogen storage device 2 is supplied to the fuel cell stack 3 to cover the power consumption of the power load 11.
The fuel reformer 1 is started to operate at the time ts in the morning of the beginning of the week to cover the power consumption of the power load 11 at the beginning of the week. After starting the operation of the fuel reformer 1, the steady operation of the hydrogen generation amount H00 is continued as soon as possible. The subsequent steps are as described in detail in <Fuel Cell Power Generation Method (Weekday Operation Mode)>.
--------------------------------

Example 2 will be described below. FIG. 2 is a block diagram showing an embodiment of the fuel cell power generation system 100 according to the present invention.

  In addition, the part which is not demonstrated about Example 2 is the same as Example 1. FIG.

  In the first embodiment, the bypass pipe LBP branched from the hydrogen pipe LH upstream of the compressor C2 joins again downstream of the valve V2. In the second embodiment, the bypass pipe LBP branches from the hydrogen pipe LH upstream of the compressor C2. The difference is that the branched pipe LBR is directly connected to the fuel cell stack 3 after passing through the valve V3 without joining again downstream of the valve V2.

  The other configurations are the same as those in the first and second embodiments.

  Example 3 will be described below. FIG. 3 is a block diagram showing an embodiment of the fuel cell power generation system 100 according to the present invention.

Parts that are not described in the third embodiment are the same as those in the first embodiment.
In the first embodiment, the hydrogen storage device is installed in the middle of the bypass pipe LBP. In the second embodiment, the hydrogen storage device is installed in the middle of the branch pipe LBR. In the third embodiment, the hydrogen storage device of the hydrogen pipe LH is used. The difference is that a hydrogen storage device is installed on the way.
The effect of the third embodiment is that the bypass piping LBP and the branch piping LBR are not provided in the middle of the hydrogen piping LH, and the components of the compressor and valves are reduced, leading to cost reduction, and the operation of the fuel cell power generation system is simplified. The failure is reduced.

Example 4 will be described below. In addition, the part which is not demonstrated about Example 4 is the same as Example 1. FIG. In the fourth embodiment, a power capacitor EC (not shown) is installed on the power line LEP. The power load 11 was switched on and the inrush power increased rapidly, but the sudden increase could be covered by the power stored in the power capacitor.
○ Comparison of power generation efficiency of fuel cell stacks of the present invention (hydrogen storage type) and comparative example (battery type) By comparing the present invention (hydrogen storage type) and comparative example (battery type), the effect of the present invention can be obtained. Let me explain more specifically.

put it here,
The present invention refers to the invention described in Example 1,
Comparative Example 1 is the same as Example 1 except as described below.
(1) Replace the hydrogen storage tank with a battery.
(2) The capacity of the fuel cell stack is set to about ½ of the present invention (hydrogen storage type).

In the present invention and Comparative Example 1, regarding the average power generation efficiency of the fuel cell stack per day, the former average power generation efficiency is 66.2%, while the latter average power generation efficiency is 38.4%. It is.
It can be seen that the former average power generation efficiency is much larger than the latter average power generation efficiency (66.2% / 38.4% = about 1.7 times). About 1.7 times this is a very large effect from the viewpoint of energy saving, and it has been shown that the power generation efficiency of 66.2% can be achieved in actual operation of the fuel cell stack. Is the first time.
If FIG. 9 is referred, transition of the power generation efficiency for every time will be understood. The former shows that the power generation efficiency is high when the power demand is small, and the latter is constant regardless of the amount of power demand. The reason for this is obvious when comparing FIG. 4 and FIG. For example, the power generation efficiency is the highest at the time when the power demand is minimum, and conversely, the power generation efficiency is the lowest at the time when the power demand is the highest. The power generation efficiency of the fuel cell stack tends to increase when the power load (also referred to as power load factor) with respect to the maximum capacity of the fuel cell stack is small. The relationship between the power demand and the power generation efficiency is not only the average power generation efficiency but also the power generation efficiency every moment. Therefore, as described above, the hydrogen storage type fuel cell power generation system cannot reduce the size of the fuel cell stack. Therefore, compared with a power storage type fuel cell power generation system, the power load factor is overwhelmingly low, and accordingly, the power storage efficiency is increased by a corresponding amount.

If this is not the case, the present invention cannot be conceived without the idea described above, and a remarkable effect that cannot be predicted by those skilled in the art can be achieved.
Boosting energy efficiency of hydrogen storage type and charging / discharging efficiency of power storage type If storage efficiency is the efficiency when going out after entering the energy storage device, boosting energy efficiency of hydrogen storage type and charging / discharging efficiency of power storage type are Both can be referred to as the storage efficiency of the energy storage device.

  Comparing the boosted energy efficiency of the hydrogen storage type and the charge / discharge efficiency of the power storage type, the boosted energy efficiency of the hydrogen storage type generally exceeds the charge / discharge efficiency of the power storage type. In the present specification, it is assumed that the boosted energy efficiency of the hydrogen storage type is substantially equal to the charge / discharge efficiency of the power storage type.

1 is a block diagram of a fuel cell power generation system 100 according to an embodiment of the present invention. It is a block diagram of the fuel cell power generation system 100 of 2 embodiment of this invention. It is a block diagram of the fuel cell power generation system 100 of three embodiment of this invention. It is an operation condition explanatory view of fuel cell power generation system 100 of one embodiment of the present invention. It is a figure which shows the change of the power generation efficiency by the power generation load of a fuel cell stack. It is a figure which shows the change of the reforming efficiency by the driving | operation load of a fuel reformer. It is an operation | movement flowchart of the fuel cell power generation system 100 of one Embodiment of this invention. It is an operation | movement flowchart (detail) of the fuel cell power generation system 100 of one Embodiment of this invention. It is a comparison figure of the power generation efficiency of this invention (hydrogen storage type) and a comparative example (electric power storage type).

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Fuel cell power generation system 1 Fuel reformer 2 Hydrogen storage device 3 Fuel cell stack 4 Waste heat recovery device 11 Electric load 12 Thermal load C1, C2, C4 Compressor V1, V2, V3 Valve LA Air piping LH Hydrogen piping LBP Bypass piping LBR Branch piping LEP Power line

Claims (18)

A fuel cell stack that generates electricity by supplying hydrogen and oxygen, a fuel reformer that generates hydrogen by supplying fuel, a hydrogen pipe that supplies hydrogen generated in the fuel reformer to the fuel cell stack, An air pipe that supplies oxygen to the fuel cell stack, a hydrogen storage device installed in the middle of the bypass pipe that is branched from the middle of the hydrogen pipe, and reconnected once a day during the day In a fuel cell power generation system that starts only for a certain period and then stops for a certain period of time and then stops completely, the fuel reformer starts to start when the fuel reformer starts to start, and the fuel reformer starts steady operation. The hydrogen amount H00 is generated so as to satisfy Equation (2), the power demand is covered by the fuel cell stack, the hydrogen is stored in the hydrogen storage device, and then the fuel reformer is completely stopped. At e = ts + to, the operation of the fuel reformer is completely stopped, and the electric power demand is transferred to the hydrogen storage device from the complete fuel stop time te to the start time ts of the next fuel reformer. A fuel cell power generation system comprising a control device that performs control so as to be covered with stored hydrogen.
here,
H = H (W) = (W / η (W)) / C (1)
H00t = Cs × H0t (2)
W0 (t): Assumed power demand H0 (t) at time t obtained from an assumed power demand curve that is a function of time t: From an assumed hydrogen quantity curve required to generate the assumed power demand W0 (t) Calculated by substituting W = W0 (t) into Equation (1) for the estimated hydrogen amount at the time t obtained.
η (W): power generation efficiency when power load W is generated by the fuel cell stack, power generation efficiency calculated in advance as a function of power load W C: heat generation amount of hydrogen per unit volume H0t: H0 (t) Total estimated hydrogen amount H00t for one day obtained by integrating at time t: Total hydrogen amount generated between the time ts when the fuel reformer is started and the time te = ts + to when it is stopped,
Cs: Safety factor of 1 or more A fuel cell stack that generates electricity by supplying hydrogen and oxygen, a fuel reformer that generates hydrogen by supplying fuel, a hydrogen pipe that supplies hydrogen generated in the fuel reformer to the fuel cell stack, An air pipe that supplies oxygen to the fuel cell stack, a hydrogen storage device installed in the middle of the branch pipe that branches directly from the middle of the hydrogen pipe and then directly connected to the fuel cell stack, and fuel reforming throughout the day In the fuel cell power generation system in which the start of the reformer is started once and is stopped for a certain period of time and then stopped completely, when the start of the fuel reformer reaches ts, the start of the fuel reformer is started and the fuel reformer is started. The steady operation of the mass device generates the hydrogen amount H00 so as to satisfy the formula (2), covers the power demand by the fuel cell stack, stores hydrogen in the hydrogen storage device, At the time of te = ts + to when the mass device is completely stopped, the operation of the fuel reformer is completely stopped, and the power demand is between the complete time te of the fuel reformer and the start time ts of the next fuel reformer. A fuel cell power generation system comprising a control device for controlling the amount to be covered with stored hydrogen stored in a hydrogen storage device.
here,
H = H (W) = (W / η (W)) / C (1)
H00t = Cs × H0t (2)
W0 (t): Assumed power demand H0 (t) at time t obtained from an assumed power demand curve that is a function of time t: From an assumed hydrogen quantity curve required to generate the assumed power demand W0 (t) Calculated by substituting W = W0 (t) into Equation (1) for the estimated hydrogen amount at the time t obtained.
η (W): power generation efficiency when power load W is generated by the fuel cell stack, power generation efficiency calculated in advance as a function of power load W C: heat generation amount of hydrogen per unit volume H0t: H0 (t) Total estimated hydrogen amount H00t for one day obtained by integrating at time t: Total hydrogen amount generated between the time ts when the fuel reformer is started and the time te = ts + to when it is stopped,
Cs: Safety factor of 1 or more A fuel cell stack that generates electricity by supplying hydrogen and oxygen, a fuel reformer that generates hydrogen by supplying fuel, a hydrogen pipe that supplies hydrogen generated in the fuel reformer to the fuel cell stack, An air pipe for supplying oxygen to the fuel cell stack, a hydrogen storage device provided in the middle of the hydrogen pipe, and starting the fuel reformer only once during a day, after a constant period of time to steady operation, complete In the fuel cell power generation system to be stopped, when the fuel reformer start-up time ts is reached, the fuel reformer starts to start, and the hydrogen is so satisfied as to satisfy Equation (2) by the steady operation of the fuel reformer. After generating the amount H00 to cover the power demand by the fuel cell stack and storing the hydrogen in the hydrogen storage device, the fuel reformer is operated at the time te = ts + to when the fuel reformer is completely stopped. It is completely stopped, and the power demand is controlled to be covered with the stored hydrogen stored in the hydrogen storage device between the time te when the fuel reformer is completely stopped and the time ts when the next fuel reformer is started. A fuel cell power generation system comprising a control device.
here,
H = H (W) = (W / η (W)) / C (1)
H00t = Cs × H0t (2)
W0 (t): Assumed power demand H0 (t) at time t obtained from an assumed power demand curve that is a function of time t: From an assumed hydrogen quantity curve required to generate the assumed power demand W0 (t) Calculated by substituting W = W0 (t) into Equation (1) for the estimated hydrogen amount at the time t obtained.
η (W): power generation efficiency when power load W is generated by the fuel cell stack, power generation efficiency calculated in advance as a function of power load W C: heat generation amount of hydrogen per unit volume H0t: H0 (t) Total estimated hydrogen amount H00t for one day obtained by integrating at time t: Total hydrogen amount generated between the time ts when the fuel reformer is started and the time te = ts + to when it is stopped,
Cs: Safety factor of 1 or more Measure the hydrogen pressure of the hydrogen storage device, and if the formula (3) is provided, stop the operation of the fuel reformer, and if the formula (4) is provided, determine whether the fuel reformer is in operation. The fuel cell power generation system according to any one of claims 1 to 3, wherein the fuel reformer is started when not in operation.
here,
PH> PC1 ··· Formula (3)
PH <PC2 ··· Equation (4)
PH: Hydrogen pressure of hydrogen storage device PC1: Upper limit value of hydrogen pressure of hydrogen storage device PC2: Lower limit value of hydrogen pressure of hydrogen storage device The fuel cell power generation system according to claim 1, further comprising an exhaust heat recovery device that recovers exhaust heat from the fuel cell stack. 6. The fuel cell power generation system according to claim 1, wherein the hydrogen storage device is a pressure cylinder. The fuel cell power generation system according to claim 1, wherein when the hydrogen storage device is a pressure cylinder, hydrogen is stored in the pressure cylinder using nighttime electric power. The fuel cell power generation system according to claim 1, further comprising a power capacitor. After operating the fuel reformer for a certain period of time on Friday, after storing the required amount of hydrogen in the hydrogen storage device between Saturday and Sunday, after stopping the fuel reformer and stopping the fuel reformer Supplies the amount of hydrogen from the hydrogen storage device to the fuel cell stack to cover the power consumption of the power load W, and operates the fuel reformer from a certain period before the start of business on Monday of the beginning of the week. The fuel cell power generation system according to claim 1. A fuel cell stack that generates electricity by supplying hydrogen and oxygen, a fuel reformer that generates hydrogen by supplying fuel, a hydrogen pipe that supplies hydrogen generated in the fuel reformer to the fuel cell stack, An air pipe that supplies oxygen to the fuel cell stack, a hydrogen storage device installed in the middle of the bypass pipe that is branched from the middle of the hydrogen pipe, and reconnected once a day during the day In a fuel cell power generation system that starts only for a certain period and then stops for a certain period of time and then stops completely, when the fuel reformer start-up time ts is reached, the start of the fuel reformer is started, and the steady state of the fuel reformer When the fuel reformer is completely stopped after operation, the hydrogen amount H00 is generated so as to satisfy the formula (2), the fuel cell stack covers the power demand, and the hydrogen is stored in the hydrogen storage device. At e = ts + to, the operation of the fuel reformer is completely stopped, and the electric power demand is transferred to the hydrogen storage device from the complete fuel stop time te to the start time ts of the next fuel reformer. A fuel cell power generation method characterized by being covered with stored hydrogen.
here,
H = H (W) = (W / η (W)) / C (1)
H00t = Cs × H0t (2)
W0 (t): Assumed power demand H0 (t) at time t obtained from an assumed power demand curve that is a function of time t: From an assumed hydrogen quantity curve required to generate the assumed power demand W0 (t) Calculated by substituting W = W0 (t) into Equation (1) for the estimated hydrogen amount at the time t obtained.
η (W): power generation efficiency when power load W is generated by the fuel cell stack, power generation efficiency calculated in advance as a function of power load W C: heat generation amount of hydrogen per unit volume H0t: H0 (t) Total estimated hydrogen amount H00t for one day obtained by integrating at time t: Total hydrogen amount generated between the time ts when the fuel reformer is started and the time te = ts + to when it is stopped,
Cs: Safety factor of 1 or more A fuel cell stack that generates electricity by supplying hydrogen and oxygen, a fuel reformer that generates hydrogen by supplying fuel, a hydrogen pipe that supplies hydrogen generated in the fuel reformer to the fuel cell stack, An air pipe that supplies oxygen to the fuel cell stack, a hydrogen storage device installed in the middle of the branch pipe that branches directly from the middle of the hydrogen pipe and then directly connected to the fuel cell stack , and fuel reforming throughout the day In the fuel cell power generation system in which the start of the reformer is started once and is stopped for a certain period of time and then stopped completely, when the start of the fuel reformer reaches ts, the start of the fuel reformer is started and the fuel reformer is started. The steady operation of the mass device generates a hydrogen amount H00 so as to satisfy Equation (2), covers the power demand by the fuel cell stack, stores the hydrogen in the hydrogen storage device, and then changes the fuel. At the time of complete stop te = ts + to, the operation of the fuel reformer is completely stopped, and the electric power demand is from the complete stop time te of the fuel reformer to the next start time ts of the fuel reformer. A fuel cell power generation method comprising: supplying hydrogen with hydrogen stored in a hydrogen storage device.
here,
H = H (W) = (W / η (W)) / C (1)
H00t = Cs × H0t (2)
W0 (t): Assumed power demand H0 (t) at time t obtained from an assumed power demand curve that is a function of time t: From an assumed hydrogen quantity curve required to generate the assumed power demand W0 (t) Calculated by substituting W = W0 (t) into Equation (1) for the estimated hydrogen amount at the time t obtained.
η (W): power generation efficiency when power load W is generated by the fuel cell stack, power generation efficiency calculated in advance as a function of power load W C: heat generation amount of hydrogen per unit volume H0t: H0 (t) Total estimated hydrogen amount H00t for one day obtained by integrating at time t: Total hydrogen amount generated between the time ts when the fuel reformer is started and the time te = ts + to when it is stopped,
Cs: Safety factor of 1 or more A fuel cell stack that generates electricity by supplying hydrogen and oxygen, a fuel reformer that generates hydrogen by supplying fuel, a hydrogen pipe that supplies hydrogen generated in the fuel reformer to the fuel cell stack, An air pipe for supplying oxygen to the fuel cell stack, a hydrogen storage device provided in the middle of the hydrogen pipe, and starting the fuel reformer only once during a day, after a constant period of time to steady operation, complete In the fuel cell power generation system to be stopped, when the fuel reformer start-up time ts is reached, the fuel reformer starts to start, and the hydrogen is so satisfied as to satisfy Equation (2) by the steady operation of the fuel reformer. After generating the amount H00 to cover the power demand by the fuel cell stack and storing the hydrogen in the hydrogen storage device, the operation of the fuel reformer is completed when the fuel reformer is completely stopped te = ts + to. The fuel cell is characterized in that the electric power demand is covered by hydrogen stored in the hydrogen storage device between the time te when the fuel reformer is completely stopped and the time ts when the next fuel reformer is started. Power generation method.
here,
H = H (W) = (W / η (W)) / C (1)
H00t = Cs × H0t (2)
W0 (t): Assumed power demand H0 (t) at time t obtained from an assumed power demand curve that is a function of time t: From an assumed hydrogen quantity curve required to generate the assumed power demand W0 (t) Calculated by substituting W = W0 (t) into Equation (1) for the estimated hydrogen amount at the time t obtained.
η (W): power generation efficiency when power load W is generated by the fuel cell stack, power generation efficiency calculated in advance as a function of power load W C: heat generation amount of hydrogen per unit volume H0t: H0 (t) Total estimated hydrogen amount H00t for one day obtained by integrating at time t: Total hydrogen amount generated between the time ts when the fuel reformer is started and the time te = ts + to when it is stopped,
Cs: Safety factor of 1 or more Further, when the hydrogen pressure of the hydrogen storage device is measured and the equation (3) is provided, the operation of the fuel reformer is stopped, and when the equation (4) is provided, whether the fuel reformer is in operation. The fuel cell power generation method according to any one of claims 10 to 12 , wherein the fuel reformer is started when it is judged and not in operation.
here,
PH> PC1 ··· Formula (3)
PH <PC2 ··· Equation (4)
PH: Hydrogen pressure of hydrogen storage device PC1: Upper limit value of hydrogen pressure of hydrogen storage device PC2: Lower limit value of hydrogen pressure of hydrogen storage device Fuel cell power generation method according to claim 10 to 1 3, wherein further comprising a heat recovery device for recovering exhaust heat from the fuel cell stack. Fuel cell power generation method according to claim 10 to 1 4, wherein the hydrogen storage device is a pressure cylinder. When the hydrogen storage device is a pressure cylinder, the fuel cell power generation method according to claim 10 to 1 5, wherein using the night power is characterized by storing hydrogen pressure bomb. Fuel cell power generation method according to claim 10 to 1 6, wherein further comprising a power capacitor. After operating the fuel reformer for a certain period of time on Friday, after storing the required amount of hydrogen in the hydrogen storage device between Saturday and Sunday, after stopping the fuel reformer and stopping the fuel reformer Supplies the amount of hydrogen from the hydrogen storage device to the fuel cell stack to cover the power consumption of the power load W, and operates the fuel reformer from a certain period before the start of business on Monday of the beginning of the week. fuel cell power generation method according to claim 10 to 1 7, wherein.

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