JP2004111167A - Hydrogen supply system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hydrogen supply system capable of keeping constant odorant concentration in hydrogen circulating in a PEFC, and also, without exhausting the odorant out of the system. <P>SOLUTION: The hydrogen supply system is equipped with a circulating path 2 circulating hydrogen in a PEFC1, a supply path 3 supplying the stored hydrogen in a tank 6 to the circulating path 2 and a purge path 4 exhausting the hydrogen released from the PEFC1 out of the system. An odorant concentration control means 5 provided at the supply path 3 controls the odorant concentration of the hydrogen at the downstream of the odorant concentration control means 5 within a given range, and a first deodorizing means 8 provided at the purge path 4 eliminates the odorant from the hydrogen released out of the system. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a hydrogen supply device capable of detecting leakage of hydrogen from a fuel cell system that generates power using hydrogen as fuel.
[0002]
[Prior art]
A polymer electrolyte fuel cell (PEFC) has a solid polymer electrolyte sandwiched between an anode electrode and a cathode electrode, and has begun to be used for various applications such as fuel cell vehicles.
[0003]
FIG. 7 shows a functional block diagram of a fuel cell system using PEFC.
The fuel cell system connects a hydrogen storage means 101 for storing hydrogen as a fuel, a PEFC 102, a circulation path 104 for circulating the hydrogen released from the PEFC 102 again to the PEFC 102, and connects the hydrogen storage means 101 and the circulation path 104. , A supply path 103 for supplying hydrogen to the PEFC 102, and a purge path 105 connected to the circulation path 104 for discharging hydrogen released from the PEFC 102 to the outside of the system.
[0004]
The hydrogen stored in the hydrogen storage means 101 is supplied to the anode electrode of the PEFC 102 via the supply path 103 and the circulation path 104, and dissociates into electrons and protons at the anode electrode. The dissociated electrons move to the cathode electrode via an external load, and the protons move through the solid polymer electrolyte to the cathode electrode, where they are oxidized by the oxidant gas (air or the like) to produce water.
[0005]
Generally, in a fuel cell system, a larger amount of hydrogen than the theoretical amount is supplied to the PEFC 102 in order to distribute hydrogen to the entire anode electrode, and hydrogen not consumed by the anode electrode is released from the PEFC 102. Then, it is circulated through the circulation path 104 again to the PEFC 102.
[0006]
Further, hydrogen supplied to the PEFC 102 is humidified in advance, and water is generated with power generation. In order to prevent such water from condensing inside the PEFC 102 to prevent the flow of hydrogen and reduce the power generation efficiency of the PEFC 102, excess water is blown into the anode electrode to purge the water. The purged hydrogen is discharged out of the system from the purge passage 105 via the purge valve.
[0007]
By the way, since hydrogen, which is the fuel of the PEFC 102, is odorless, it is difficult to detect leakage from the fuel cell system. Therefore, in a system using hydrogen such as a fuel cell vehicle, a system for detecting a hydrogen leak by arranging a hydrogen sensor or the like for detecting a hydrogen concentration has been studied.
[0008]
As another system for detecting hydrogen leakage, in Patent Document 1, as shown in FIG. 8, an odorant adding means 106 is provided on the upstream side of the supply path 103, and hydrogen to which the odorant is added is circulated. I'm supposed to. By the way, since the odorant poisons the catalyst of the PEFC 102, in Patent Literature 1, hydrogen is supplied to the PEFC 102 after the odorant is removed by the deodorizing means 107 provided on the downstream side of the supply path 103. ing.
[0009]
[Patent Document 1]
JP-A-2002-29701 (paragraphs 0041 to 0050)
[0010]
[Problems to be solved by the invention]
Although the method of Patent Document 1 is excellent in that an odorant is added to hydrogen, it has a problem in that it is not possible to detect leakage of hydrogen generated downstream of the deodorizing means 107 (such as the PEFC 102).
[0011]
In order to solve this problem, as shown in FIG. 9, the odorant adding means 106 provided on the upstream side of the supply path 103 is provided with an odorant (for example, sulfides or the like) that is less poisoned to the PEFC 102. ) Is added to hydrogen, and an odorant is supplied to the PEFC 102.
[0012]
However, in this method, since the odorant is not consumed by the PEFC 102, the odorant is gradually concentrated in the circulation path 104, thereby lowering the power generation efficiency of the PEFC 102, or depending on the type of the odorant, The odorant concentrated at a high concentration may poison PEFC102.
[0013]
The present invention has been made in view of such a problem, and an object of the present invention is to provide a hydrogen supply device that can maintain a constant odorant concentration in hydrogen circulating in a PEFC.
[0014]
[Means for Solving the Problems]
The present invention is configured as follows in order to solve the above-mentioned problem.
The invention according to claim 1 is a hydrogen supply device that supplies hydrogen containing an odorant to a fuel cell that generates power by an electrochemical reaction between hydrogen and oxygen. A circulating path for circulating and supplying again to the fuel cell, and a supply path for supplying hydrogen stored in a tank to the circulating path, and controlling an odorant concentration of hydrogen in the circulating path. A hydrogen supply device provided with control means.
[0015]
According to the first aspect of the present invention, since the odorant concentration control means is provided, the odorant concentration of hydrogen in the circulation path downstream of the odorant concentration control means can be controlled within a predetermined range. . In the embodiment described later, the odorant concentration control unit is provided in the supply path. In addition, in an embodiment to be described later, the circulation path is shown as an odorized hydrogen circulation path W (circulation path 2 = circulation path in a narrow sense) in FIG. 1 and the like.
[0016]
The invention according to claim 2 has a concentration sensor for measuring the odorant concentration in the circulation path, and the odorant concentration in the circulation path is determined based on the odorant concentration measured by the concentration sensor. The hydrogen supply device according to claim 1, wherein the odorant concentration is controlled.
[0017]
The invention according to claim 2 has a concentration sensor for measuring the concentration of odorant in hydrogen in the circulation path. Therefore, the odorant concentration control means uses the odorant concentration measured by the concentration sensor. Based on the above, the odorant concentration of hydrogen in the circulation path can be reliably controlled.
[0018]
According to a third aspect of the present invention, the odorant concentration control means includes a purge path connected to the circulation path for discharging hydrogen in the circulation path to the outside of the system. The hydrogen supply device according to claim 1 or 2, wherein the odorant is discharged outside the system to control the concentration of the odorant in the circulation path so as to decrease.
[0019]
The invention according to claim 3 is provided with a purge path connected to the circulation path, and discharges hydrogen and an odorant (odorized hydrogen) from the purge path to the outside of the system to thereby provide an odorant. Decrease concentration. When the odorant concentration in the circulating hydrogen is lower than the odorant concentration in the hydrogen circulating in the circulation path, the hydrogen concentration in the circulation path can be effectively reduced.
[0020]
According to a fourth aspect of the present invention, the hydrogen stored in the tank contains the odorant in advance, and the odorant concentration control means includes a deodorizing means provided in the supply path, and the deodorizing means. The odorant concentration control means is configured to bypass the odorant concentration of hydrogen in the circulation passage through the bypass passage when the odorant concentration in the circulation passage is lower than a predetermined concentration. The hydrogen supply device according to claim 1, wherein hydrogen containing an odorant is supplied to a circulation path.
[0021]
The invention according to claim 4 supplies hydrogen containing an odorant in advance. The odorant concentration control means can supply the hydrogen treated by the deodorizing means or the hydrogen which bypasses the deodorizing means to the circulation path. When the odorant concentration in the circulation path is reduced to less than the predetermined concentration, hydrogen containing the odorant is supplied to the circulation path in advance through the bypass path (because the supply ratio is increased). It is possible to increase the odorant concentration. Note that the “predetermined value” below the predetermined density corresponds to the “lower limit value” in S2 of FIG. 2 in an embodiment described later.
[0022]
The invention according to claim 5 is characterized in that when the odorant concentration of hydrogen in the circulation path is equal to or higher than the predetermined concentration, the deodorized hydrogen is supplied to the circulation path through the deodorizing means. 2. The hydrogen supply device according to 1.
[0023]
The invention according to claim 5 supplies hydrogen containing an odorant in advance. The odorant concentration control means can supply the hydrogen treated by the deodorizing means or the hydrogen which bypasses the deodorizing means to the circulation path. When the odorant concentration in the circuit increases to a predetermined concentration or more, the deodorizing means supplies deodorized hydrogen to the circuit because hydrogen is supplied to the circuit (the supply ratio is increased). Can be reduced. Note that the “predetermined density” above the predetermined density corresponds to the “upper limit” in S3 of FIG. 2 in an embodiment described later.
[0024]
The invention according to claim 6 is characterized in that the hydrogen stored in the tank is pure hydrogen, the odorant concentration control means is an odorant connected to the supply path, and the odorant concentration control is performed. 2. The hydrogen supply according to claim 1, wherein when the odorant concentration of hydrogen in the circulation path is lower than a predetermined concentration, the odorant adds the odorant to the hydrogen by the odorizing means. 3. Device.
[0025]
According to the invention described in claim 6, pure hydrogen stored in the tank can be odorized by the odorizing means. The odor concentration control means adds the odorant by the odor means when the hydrogen odorant concentration in the circulation path is low.
[0026]
The invention according to claim 7 is provided with a purge path connected to the circulation path for discharging hydrogen in the circulation path to the outside of the system, and the hydrogen in the circulation path is determined based on the amount of hydrogen released to the outside of the system. The hydrogen supply device according to claim 1, wherein the amount of decrease in the odorant concentration is calculated, and the odorant concentration control means controls the odorant concentration based on the decrease amount. is there.
[0027]
According to a seventh aspect of the present invention, there is provided a purge passage connected to the circulation passage, and the amount of decrease in the odorant concentration is calculated from the amount of hydrogen released from the purge passage to the outside of the system, thereby obtaining an odor. By adding the odorant to the supply hydrogen by an amount corresponding to the decrease amount, the odorant concentration control means can control the odorant concentration of hydrogen in the circulation path within a predetermined range.
[0028]
The invention according to claim 8 is provided with a purge path connected to the circulation path for discharging hydrogen in the circulation path to the outside of the system, and a hydrogen recovery container containing a hydrogen storage alloy is connected to the purge path. The hydrogen supply device according to claim 1, wherein the hydrogen discharged to the outside of the system is recovered by the hydrogen recovery container, and the recovered hydrogen is returned to the circulation path.
[0029]
The invention according to claim 8 is provided with a purge path connected to the circulation path, and the purge path is provided with a hydrogen recovery container for recovering the purged hydrogen. Since this hydrogen recovery container is connected to the circulation path, the purged hydrogen discharged outside the system can be reused and returned to the fuel cell again.
[0030]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings as appropriate.
(1st Embodiment)
In the first embodiment, hydrogen to which an odorant has been added is stored in the tank in advance, and a concentration sensor for measuring the odorant concentration is provided in the circulation path. An example in which the collection is not performed by the collection container will be described.
[0031]
FIG. 1 is a block diagram of a fuel cell system to which the hydrogen supply device according to the first embodiment is applied.
The hydrogen supply device includes a circulation path 2 for circulating hydrogen to the PEFC 1, a supply path 3 connected to the circulation path 2 for supplying hydrogen to the PEFC 1, and discharging hydrogen released from the PEFC 1 to the outside of the system. And a purge path 4 for performing the operation.
[0032]
Hydrogen which is a fuel for operating the PEFC 1 is stored in the tank 6 after adding a predetermined concentration of odorant in advance. Note that hydrogen containing a predetermined concentration of odorant is hereinafter referred to as odorant-added hydrogen.
[0033]
An odorant concentration control unit 5 is provided in the supply path 3 connecting the tank 6 and the circulation path 2. The odorant concentration control means 5 includes a second deodorizing means 5a provided in the supply path 3, a bypass path 5b that bypasses the second deodorizing means 5a, and a second deodorizing means 5a and a bypass path 5b. And a switching valve 5c for switching the flow path of the air conditioner.
[0034]
Here, the upstream supply path 3 is referred to as an upstream supply path 3a and the downstream supply path 3 is referred to as a downstream supply path 3b with the odorant concentration control means 5 as a boundary.
Further, the downstream supply path 3b, the circulation path 2 and the PEFC 1 are collectively referred to as an odorous hydrogen circulation path W.
[0035]
The odorant concentration control means 5 has a function of controlling the odorant concentration in the hydrogen present in the odorized hydrogen circulation path W. That is, when the odorant-added hydrogen flowing from the tank 6 is supplied to the odorant hydrogen circulation path W via the second deodorizing means 5a, no odorant is added to the odorant hydrogen circulation path W. . On the other hand, when the odorant-added hydrogen is supplied to the odorant hydrogen circulation path W via the bypass path 5b, an odorant is added to the odorant hydrogen circulation path W.
[0036]
A regulator (not shown) is provided in the supply path 3, and the high-pressure hydrogen stored in the tank 6 is supplied to the PEFC 1 after the pressure is adjusted.
Immediately before the PEFC 1 in the circulation path 2, a humidifier 9 for humidifying the hydrogen introduced into the PEFC 1 is provided. Further, the circulation path 2 is provided with a concentration sensor 7 for measuring the odorant concentration in hydrogen existing in the odorized hydrogen circulation path W.
[0037]
The purge path 4 is provided with a purge valve 4a, and the purge of the hydrogen in the odorous hydrogen circulation path W is performed by appropriately opening the purge valve 4a. The purge passage 4 also constitutes a part of the odorant concentration control means 5. The purged hydrogen is introduced into the gas-liquid separator 10 provided in the purge passage 4 and is separated into water and hydrogen. At this stage, the water is separately discharged outside the system. On the other hand, hydrogen is introduced into the first deodorizing means 8 and, after the odorant is removed, is introduced into the catalytic combustor 11 and burned.
[0038]
Further, the hydrogen supply device has an ECU 12, and the ECU 12 monitors the odorant concentration in the hydrogen present inside the odorous hydrogen circulation path W measured by the concentration sensor 7. Further, the ECU 12 monitors the cell voltage of the PEFC1. The ECU 12 determines the necessity of purging in accordance with the change in the cell voltage, and controls opening and closing of the purge valve 4a.
[0039]
Further, the ECU 12 controls the switching valve 5c according to the odorant concentration measured by the concentration sensor 7 and / or the presence or absence of the purge, and allows the odorant-added hydrogen introduced from the tank 6 to flow through the bypass passage 5b. It is determined whether or not to distribute to the second deodorizing means 5a.
[0040]
Next, the operation of the first embodiment will be described with reference to the flowchart of FIG. In the following description, FIG. 1 will be referred to as appropriate.
[0041]
First, in S1, the concentration sensor 7 measures the odorant concentration in the hydrogen present in the odorous hydrogen circulation path W, and outputs the result to the ECU 12.
In the subsequent steps S2 and S3, the ECU 12 determines whether or not the odorant concentration is within a predetermined range.
[0042]
That is, in S2, it is determined whether or not the odorant concentration is equal to or higher than the lower limit of the predetermined range. If it is determined in S2 that “odorant concentration ≧ lower limit value” (Y), the process proceeds to S3.
[0043]
On the other hand, if it is determined in S2 that “odorant concentration <lower limit value” (N), it indicates that the odorant concentration in the odorant hydrogen circulation path W is too low. Controls the switching valve 5c to supply hydrogen to the odorized hydrogen circulation path W through the bypass path 5b. As a result, the odorant-added hydrogen is supplied to the odorized hydrogen circulation path W, so that the odorant concentration in the odorized hydrogen circulation path W increases.
After S9, the process returns to S1.
[0044]
In S3, it is determined whether or not the odorant concentration is equal to or lower than the upper limit of the predetermined range. In S3, if “odorant concentration ≦ upper limit” (Y), it indicates that the odorant concentration in the odorant hydrogen circulation path W is within the specified concentration range, and the process proceeds to S4.
[0045]
On the other hand, in the case of “odorant concentration> upper limit” in S3 (N), it indicates that the odorant concentration in the odorant hydrogen circulation path W is too high, and in S10, the ECU 12 By controlling the switching valve 5c to supply hydrogen to the odorized hydrogen circulation path W via the second deodorizing means 5a, the addition of the odorant to the odorized hydrogen circulation path W is stopped.
[0046]
Further, in S11, the ECU 12 issues a valve opening command to the purge valve 4a and performs purging for a predetermined time in order to prevent the PEFC 1 from being poisoned by the odorant, thereby performing a purge for a predetermined period of time. Lower the odorant concentration. After S11, the process returns to S1.
[0047]
In S4, since the odorant concentration in the odorized hydrogen circulation path W is within a predetermined range, the ECU 12 controls the switching valve 5c to add hydrogen via the second deodorizing means 5a. By supplying the odorant to the odorous hydrogen circulation path W, the addition of the odorant to the odorous hydrogen circulation path W is stopped.
[0048]
In PEFC1, since only hydrogen is consumed, the amount of the odorant present in the odorous hydrogen circulation path W does not decrease unless purging is performed. Therefore, even if the odorant-removed hydrogen is supplied to the odorant hydrogen circulation path W in S4, the odorant concentration in the odorant hydrogen circulation path W is kept substantially constant.
[0049]
Subsequently, in S5, the ECU 12 determines whether or not hydrogen purging has been started, that is, whether or not the purge valve 4a has been opened. In S5, when it is determined that the purge of hydrogen has not been performed (N), the process returns to S1.
[0050]
On the other hand, if it is determined that the purge of hydrogen has been started (Y), the process proceeds to S6. In S6, in order to compensate for the odorant concentration in the odorous hydrogen circulation path W that decreases with the purge, the ECU 12 controls the switching valve 5c to supply hydrogen to the odorous hydrogen via the bypass path 5b. Supply to circulation path W. Thus, since the odorant-added hydrogen is supplied to the odorant hydrogen circulation path W, the decrease in the odorant concentration due to the purge can be compensated.
[0051]
Subsequently, in S7, the ECU 12 determines whether or not the purging is completed. If the purging is continuing (N), the process returns to S6, and the supply of the odorant-added hydrogen to the odorant hydrogen circulation path W is stopped. Continued. On the other hand, if it is determined that the purging has been completed (Y), the process proceeds to S8.
[0052]
In S8, the ECU 12 controls the switching valve 5c to supply hydrogen to the odorized hydrogen circulation path W via the second deodorizing means 5a, so that the odorant is supplied to the odorized hydrogen circulation path W. Stop adding. Thereafter, the process returns to S1.
[0053]
In this flowchart, in the processing of S5 to S8, the odorant-added hydrogen is supplied to the odorous hydrogen circulation path W in synchronization with the purge of hydrogen. With such a configuration, even during the purging of hydrogen, the odorant concentration in the odorized hydrogen circulation path W can be maintained within a predetermined range. Even if is leaked, it can be detected.
[0054]
In this flowchart, as shown by the dotted line, a configuration in which the processing from S4 to S1 is performed without performing the processing from S5 to S8 is also conceivable. In this case, since the ECU 12 does not detect the purge of hydrogen, the odorant concentration that decreases during the purge is compensated in the process of S9.
[0055]
In this configuration, since the odorant is not added to the odorized hydrogen circulation path W during the purge of hydrogen, the amount of the odorant that must be removed by the first deodorizing means 8 during the purge is reduced. There is the advantage of being reduced.
[0056]
As described above, in the hydrogen supply device of the first embodiment, since the odorant concentration in the odorized hydrogen circulation path W can be within a predetermined range, the hydrogen leak generated in the circulation path 2 and the PEFC 1 is reliably detected. And PEFC1 is not poisoned by the highly concentrated odorant.
Moreover, since the concentration of hydrogen does not relatively decrease due to the concentrated odorant, power generation can be appropriately performed.
[0057]
Further, since the odorant-added hydrogen is used, it is also possible to detect hydrogen leakage occurring in the tank 6 and the upstream supply passage 3a.
[0058]
Further, when purging hydrogen, hydrogen is discharged out of the system after the odorant is removed by the first deodorizing means 8, so that erroneous detection of hydrogen leakage occurs or the location of hydrogen leakage cannot be specified. There is no fear of doing.
[0059]
Here, as the odorant added to hydrogen, the presence thereof can be confirmed by the odor, and there is no particular limitation as long as it is a substance that is less toxic to PEFC1, and sulfides, thiophenes, mercaptans, amines, and Saturated hydrocarbons, aldehydes and the like are preferred. Among these, a sulfur-based substance, which hardly changes in concentration because it hardly adheres to a pipe or the like, is preferable.
[0060]
Further, the predetermined range of the odorant concentration is desirably a concentration at which poisoning of PEFC1 can be suppressed to a practically acceptable level and the presence thereof can be confirmed by odor. Specific numerical values differ depending on the substance used as the odorant, and therefore cannot be unambiguously described. However, the lower limit is preferably about 2 to 3 ppm, and the upper limit is preferably about 8 to 10 ppm.
If the lower limit is less than this range, the odor is weakened, making it difficult to confirm its presence. If the upper limit exceeds this range, the possibility of poisoning PEFC1 increases.
[0061]
As the first deodorizing means 8 and the second deodorizing means 5a, an adsorbent can be used. For example, zeolite ion-exchanged with a specific metal ion, activated carbon carrying a metal salt or the like can be used as the adsorbent. The method using an adsorbent is preferable because it does not require heating or the like and is easy to handle.
[0062]
In particular, when the odorant is a sulfur-based substance, it is also possible to employ a hydrodesulfurization method as the first deodorizing means 8 and the second deodorizing means 5a. In this method, hydrogen and an odorant are introduced into a Co—Mo catalyst or the like, a sulfur compound is decomposed into hydrogen sulfide, and the hydrogen sulfide is adsorbed on zinc oxide or the like, thereby removing the odorant. By using this method, the odorant concentration can be reduced to the ppm level.
[0063]
(2nd Embodiment)
In the second embodiment, hydrogen to which an odorant has been added is stored in the tank 6 in advance, the concentration sensor 7 is not installed in the circulation path 2, and purged hydrogen is recovered by the hydrogen recovery container 13. An example is shown below.
[0064]
FIG. 3 is a block diagram of a fuel cell system to which the hydrogen supply device according to the second embodiment is applied. In FIG. 3, the same components as those in FIG. 1 are denoted by the same reference numerals, and description thereof will be omitted.
[0065]
The hydrogen supply device according to the second embodiment collects purge hydrogen using a hydrogen storage alloy (hereinafter referred to as MH) downstream of the first deodorizing means 8 in that the concentration sensor 7 is not provided in the circulation path 2. The second embodiment is different from the first embodiment in that a hydrogen recovery container 13 is provided and a reflux path 14 for refluxing hydrogen from the hydrogen recovery container 13 to the circulation path 2 is provided.
[0066]
Although details will be described later, in the second embodiment, the odorant concentration in the odorized hydrogen circulation path W is estimated by calculation. That is, the odorant concentration in the odorant hydrogen circulation path W is reduced only by purging with hydrogen because the odorant is not consumed by the PEFC 1, and is supplied by the supply of odorant-added hydrogen through the bypass passage 5b or by the supply of hydrogen. Increased by consumption. Therefore, if the odorant concentration in the odorant hydrogen circulation path W is given as the initial value, the odorant hydrogen circulation path is determined from the hydrogen purge amount and the supply amount of the odorant-added hydrogen via the bypass path 5b. The odorant concentration in W can be estimated.
[0067]
In the second embodiment, the purged hydrogen is recovered by the hydrogen recovery container 13 and is appropriately returned to the circulation path 2 through the return path 14. The hydrogen recovery container 13 is provided with heating / cooling means (not shown) for recovering and refluxing hydrogen.
[0068]
Subsequently, the operation of the second embodiment will be described with reference to the flowchart of FIG. In the following description, FIG. 3 will be referred to as appropriate.
[0069]
First, in S21, it is determined whether or not the hydrogen supply device (fuel cell system) is started for the first time, that is, whether or not the hydrogen supply device is started for the first time. When the hydrogen supply device is started for the first time (N), since the odorant does not exist in the odorous hydrogen circulation path W, it is necessary to supply the odorant to the odorous hydrogen circulation path W. .
[0070]
Therefore, in S22, the ECU 12 controls the switching valve 5c to supply hydrogen to the odorized hydrogen circulation path W through the bypass path 5b. As a result, the odorant-added hydrogen is supplied to the odorized hydrogen circulation path W, so that the odorant concentration in the odorized hydrogen circulation path W increases.
[0071]
Subsequently, in S23, it is determined whether or not the odorant concentration initial value in the odorized hydrogen circulation path W falls within a predetermined range obtained by calculation in advance. If the odorant concentration initial value is less than the predetermined range (N), the process returns to S22 and the supply of odorant-added hydrogen is continued. On the other hand, if the odorant concentration initial value falls within the predetermined range (Y), the process proceeds to S24.
[0072]
In S21, when it is determined that the hydrogen supply device has been activated several times in the past (N), since the odorant of a predetermined concentration already exists in the odorous hydrogen circulation path W, The process shifts to S24.
[0073]
In S24, since an odorant having a concentration within a predetermined range already exists in the odorized hydrogen circulation path W, the ECU 12 controls the switching valve 5c to add hydrogen through the second deodorizing means 5a. By supplying the odorant to the odorous hydrogen circulation path W, the addition of the odorant to the odorous hydrogen circulation path W is stopped.
[0074]
Subsequently, in S25, the presence or absence of the purge is determined. If it is determined that purging has not been performed (N), the process returns to S24, and hydrogen is supplied to the odorized hydrogen circulation path W via the second deodorizing means 5a.
[0075]
On the other hand, when it is determined that the purging has been newly performed (Y), the process proceeds to S26, and the odorant reduction amount in the odorous hydrogen circulation path W is calculated. The amount of odorant reduction can be calculated by knowing the amount of gas (hydrogen + odorant) (purge amount) discharged by the purge. The purge amount can be obtained, for example, from the opening time of the purge valve 4a. In S27 following S26, the ECU 12 controls the switching valve 5c to supply hydrogen to the odorized hydrogen circulation path W via the bypass path 5b.
[0076]
Then, in S28, the amount of the odorant reduced calculated in S26 is compared with the amount of the odorant added to the odorized hydrogen circulation path W in S27, and the amount of the odorant reduced by the purge is compensated. If it is determined (Y), the process returns to S24. On the other hand, when the amount of the odorant reduced by the purge is not compensated (N), the process returns to S27, and the supply of the odorant-added hydrogen to the odorant hydrogen circulation path W is performed.
[0077]
As described above, in the hydrogen supply device of the second embodiment, since the odorant concentration in the odorized hydrogen circulation path W can be within a predetermined range, the hydrogen leak generated in the circulation path 2 and the PEFC 1 is reliably detected. And PEFC1 is not poisoned by the highly concentrated odorant. Further, a decrease in the hydrogen concentration is suppressed. When hydrogen is consumed by the PEFC 1, the odorant concentration in the hydrogen increases. Therefore, the odorant concentration may be calculated in consideration of the hydrogen consumption and the power generation amount.
[0078]
Further, since the odorant-added hydrogen is used, it is also possible to detect hydrogen leakage occurring in the tank 6 and the upstream supply passage 3a.
Further, since the purged hydrogen is collected by the hydrogen recovery container 13 and is reused in the PEFC 1, the utilization efficiency of hydrogen is increased.
[0079]
(Third embodiment)
In the third embodiment, pure hydrogen to which no odorant is added is stored in the tank 6, a concentration sensor 7 is provided in the circulation path 2, and purged hydrogen is recovered by the hydrogen recovery container 13. An example is shown below.
[0080]
FIG. 5 is a functional block diagram of a fuel cell system to which the hydrogen supply device according to the third embodiment is applied. In FIG. 5, the same components as those in FIG. 3 are denoted by the same reference numerals, and description thereof will be omitted.
[0081]
The hydrogen supply device according to the third embodiment is different from the second embodiment in that the tank 6 stores pure hydrogen to which no odorant is added. Accordingly, the configuration of the odorant concentration control means 5 is changed. That is, the odorant concentration control means 5 includes an odorant means 5d connected to the supply path 3 via the valve 5e.
[0082]
Hydrogen containing a high concentration of an odorant is stored in the odorizing means 5d. If the odorant concentration of hydrogen in the odorant hydrogen circulation path W is less than a predetermined range, the valve is activated by a command from the ECU 12. The valve 5e is opened, the hydrogen containing the odorant at a high concentration is mixed with the pure hydrogen flowing through the supply path 3, and the odorant-added hydrogen is supplied into the odorant hydrogen circulation path W.
[0083]
When the odorant concentration of hydrogen in the odorized hydrogen circulation path W is within a predetermined range, the valve 5e is closed, and pure hydrogen is supplied to the odorized hydrogen circulation path W.
[0084]
Further, if for some reason the odorant concentration of hydrogen in the odorized hydrogen circulation path W exceeds a predetermined range, pure hydrogen is continuously supplied to the odorized hydrogen circulation path W and the ECU 12 By opening the purge valve 4a, the purging of hydrogen in the hydrogen odor circulating path W is performed, and the odorant concentration of hydrogen in the hydrogen odor circulating path W is reduced.
[0085]
Next, the operation of the third embodiment will be described with reference to the flowchart of FIG. In the following description, FIG. 5 will be referred to as appropriate.
[0086]
First, in S41, the concentration sensor 7 measures the odorant concentration in the hydrogen present in the odorous hydrogen circulation path W, and outputs the result to the ECU 12.
In the subsequent processes of S42 and S43, the ECU 12 determines whether or not the odorant concentration is within a predetermined range.
[0087]
That is, in S42, it is determined whether or not the odorant concentration is equal to or higher than the lower limit of the predetermined range. If it is determined in S42 that “odorant concentration ≧ lower limit value” (Y), the process proceeds to S43.
[0088]
On the other hand, if it is determined in S42 that “odorant concentration <lower limit value” (N), it indicates that the odorant concentration in the odorant hydrogen circulation path W is too low. Opens the valve 5e and supplies the supply path 3 with hydrogen containing a high concentration of odorant stored in the odorizing means 5d. As a result, the odorant-added hydrogen is supplied to the odorized hydrogen circulation path W, so that the odorant concentration in the odorized hydrogen circulation path W increases. After S45, the process returns to S41.
[0089]
In S43, it is determined whether or not the odorant concentration in the odorized hydrogen circulation path W is equal to or lower than the upper limit of the predetermined range. If “odorant concentration ≦ upper limit” in S43 (Y), it indicates that the odorant concentration in the odorant hydrogen circulation path W is within the specified concentration range, and the process proceeds to S44.
[0090]
On the other hand, if “odorant concentration> upper limit” in S43 (N), it indicates that the odorant concentration in the odorant hydrogen circulation path W is too high, and in S46, the ECU 12 The valve 5e is closed to supply pure hydrogen to the odorous hydrogen circulation path W.
[0091]
Further, in S47, the ECU 12 issues a valve opening command to the purge valve 4a and performs purging for a predetermined time in order to prevent the PEFC 1 from being poisoned by the odorant. Lower the odorant concentration. After S47, the process returns to S41.
[0092]
In S44, since the odorant concentration in the odorized hydrogen circulation path W is within a predetermined range, the ECU 12 controls the valve 5e to supply pure hydrogen to the odorized hydrogen circulation path W. Then, the addition of the odorant to the odorized hydrogen circulation path W is stopped.
[0093]
In PEFC1, since only hydrogen is consumed, the amount of the odorant present in the odorous hydrogen circulation path W does not change unless purging is performed. Therefore, even if pure hydrogen is supplied to the odorized hydrogen circulation path W in S44, the odorant concentration in the odorized hydrogen circulation path W is kept substantially constant.
[0094]
In this flowchart, the supply of the odorant-added hydrogen synchronized with the purge of the hydrogen as shown in S5 to S8 in FIG. 2 is not performed, but, of course, corresponds to S5 to S8 in FIG. It is also possible to add the processing after S44.
[0095]
As described above, in the hydrogen supply device according to the third embodiment, the odorant concentration in the odorant hydrogen circulation path W can be set within a predetermined range, so that the hydrogen leakage generated in the circulation path 2 and the PEFC 1 is reliably detected. And PEFC1 is not poisoned by the highly concentrated odorant.
[0096]
The present invention is not limited to the above-described embodiments (first to third embodiments) but can be widely modified and implemented. For example, the first embodiment to the third embodiment can be appropriately combined and implemented. Also, the fuel cell has been described as a PEFC, but is not limited to this fuel cell. Hydrogen may be supplied from any of a high-pressure hydrogen tank, a hydrogen storage alloy, and liquefied hydrogen. Further, the present invention can be applied to a fuel cell system installed in vehicles such as vehicles and ships, buildings and facilities, and the like.
[0097]
【The invention's effect】
The present invention has the following remarkable effects.
The hydrogen supply device of the present invention (claim 1) supplies hydrogen containing an odorant, so that even when hydrogen leakage occurs, it is possible to recognize the leakage by odor. Further, the circulating passage increases the odorant concentration by consuming hydrogen by the power generation of the fuel cell. However, the provision of the means for controlling the concentration causes inconvenience due to the high odorant concentration (for example, It is possible to prevent fuel cell poisoning. Alternatively, it is possible to prevent inconvenience (oversight of leakage) due to low concentration. Therefore, it is possible to provide a hydrogen supply device capable of maintaining a constant odorant concentration in hydrogen circulating in the fuel cell.
[0098]
The hydrogen supply device according to the present invention (claim 2) can control the odorant concentration with higher accuracy.
[0099]
ADVANTAGE OF THE INVENTION The hydrogen supply apparatus (Claim 3) of the present invention can reliably lower the odorant concentration in the circulation path with a simple configuration.
[0100]
The hydrogen supply device according to the present invention (claim 4) can reliably increase the odorant concentration in the circulation path by passing through the bypass path when hydrogen contains an odorant in advance.
[0101]
In the hydrogen supply device of the present invention (claim 5), even when hydrogen contains an odorant in advance, it is possible to reliably lower the odorant concentration in the circulation path by passing through the deodorizing means.
[0102]
In the hydrogen supply device of the present invention (claim 6), even when hydrogen does not contain an odorant, odor is given by the odorant, and the hydrogen concentration in the circulation path can be surely increased.
[0103]
The hydrogen supply apparatus according to the present invention calculates the amount of decrease in the odorant concentration in the odorant hydrogen circulation path based on the amount of hydrogen purge, and the odorant concentration control means calculates the decrease amount. Is supplied, the odorant concentration in the odorant hydrogen circulation path can be kept within a predetermined range without providing a concentration sensor (claim 3).
[0104]
In the hydrogen supply device of the present invention (claim 8), a hydrogen recovery container is provided in the purge passage, and the purged hydrogen is recovered and returned to the circulation passage again, so that the hydrogen utilization efficiency of the hydrogen supply device can be improved. it can.
[Brief description of the drawings]
FIG. 1 is a functional block diagram of a first embodiment of the present invention.
FIG. 2 is a flowchart showing the operation of the first embodiment of the present invention.
FIG. 3 is a functional block diagram of a second embodiment of the present invention.
FIG. 4 is a flowchart showing the operation of the second embodiment of the present invention.
FIG. 5 is a functional block diagram according to a third embodiment of the present invention.
FIG. 6 is a flowchart showing the operation of the third embodiment of the present invention.
FIG. 7 is a functional block diagram of a hydrogen supply device using PEFC.
FIG. 8 is a functional block diagram of a hydrogen supply device of Patent Document 1.
FIG. 9 is a functional block diagram of a conventional hydrogen supply device.
[Explanation of symbols]
1 PEFC
2 circuit
3 Supply channel
3a Upstream supply path
3b Downstream supply path
4 Purge path
4a Purge valve
5 Odorant concentration control means
5a Second deodorizing means
5b Bypass road
5c switching valve
5d odor means
5e valve
6 tanks
7 Concentration sensor
8 First deodorizing means
9 Humidifier
10 Gas-liquid separator
11 Catalytic combustor
12 ECU
W Odor hydrogen circulation route

Claims (8)

In a hydrogen supply device that supplies hydrogen containing an odorant to a fuel cell that generates power by an electrochemical reaction between hydrogen and oxygen,
A circulation path for circulating unused hydrogen discharged from the fuel cell and supplying the hydrogen again to the fuel cell, and a supply path for supplying hydrogen stored in a tank to the circulation path;
A hydrogen supply device comprising an odorant concentration control means for controlling an odorant concentration of hydrogen in the circulation path. The circuit has a concentration sensor that measures the odorant concentration,
The hydrogen supply device according to claim 1, wherein the odorant concentration in the circulation path is controlled based on the odorant concentration measured by the concentration sensor. The odorant concentration control means is connected to the circulation path, and includes a purge path for discharging hydrogen in the circulation path to the outside of the system,
The hydrogen according to claim 1 or 2, wherein the hydrogen and the odorant in the circulation path are discharged to the outside of the system to control the concentration of the odorant in the circulation path to be reduced. Feeding device. The hydrogen stored in the tank contains the odorant in advance, and the odorant concentration control means includes a deodorization means provided in the supply path, and a bypass capable of flowing hydrogen around the deodorization means. From the road,
When the odorant concentration of hydrogen in the circulation path is less than a predetermined concentration, the odorant concentration control unit supplies hydrogen containing an odorant to the circulation path via the bypass path. The hydrogen supply device according to claim 1, wherein: The hydrogen stored in the tank contains the odorant in advance, and the odorant concentration control means includes a deodorization means provided in the supply path, and a bypass capable of flowing hydrogen around the deodorization means. From the road,
The hydrogen supply device according to claim 1, wherein when the odorant concentration of hydrogen in the circulation path is equal to or higher than the predetermined concentration, the deodorized hydrogen is supplied to the circulation path through the deodorizing means. The hydrogen stored in the tank is pure hydrogen, the odorant concentration control means is an odorant connected to the supply path,
The odorant concentration control means, wherein when the odorant concentration of hydrogen in the circulation path is less than a predetermined concentration, the odorant means adds an odorant to the hydrogen by the odorant means. 2. The hydrogen supply device according to 1. A purge path connected to the circulation path for discharging hydrogen in the circulation path to the outside of the system;
From the amount of hydrogen released outside the system, calculate the amount of decrease in the odorant concentration of hydrogen in the circulation path,
2. The hydrogen supply device according to claim 1, wherein the odorant concentration control unit controls the odorant concentration based on the decrease amount. 3. A purge path connected to the circulation path for discharging hydrogen in the circulation path to the outside of the system;
A hydrogen recovery container including a hydrogen storage alloy is connected to the purge path, the hydrogen released to the outside of the system is recovered by the hydrogen recovery container, and the recovered hydrogen is returned to the circulation path. The hydrogen supply device according to claim 1, wherein

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