JP2016162539A - Fuel battery power generation device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fuel battery power generation device that can suppress consumption of impurities removing means without preparing impurity concentration detection means, extend the lifetime and prevent reduction in power and durability of the fuel battery.SOLUTION: A fuel battery power generation device is configured so that oxidant gas supply means 2 is provided with oxidant gas impurity removing means 4 for removing impurities contained in oxidant gas. A part of oxidant gas supplied to a fuel battery 1 is supplied to the fuel battery 1 without passing through the oxidant gas impurity removing means 4. Accordingly, there can be provided a fuel battery power generation device in which the consumption of the oxidant gas impurity removing means 4 is suppressed without preparing any impurity concentration detection means, the lifetime can be extended, and reduction in power and durability of the fuel battery 1 can be prevented.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a fuel cell power generator that does not cause a decrease in output or durability due to impurities contained in a use environment.

  In recent years, there has been a demand for the development of a high-efficiency and clean energy source, and fuel cells are attracting attention as one candidate for the development. A fuel cell (for example, a polymer electrolyte fuel cell) performs an electrochemical reaction (power generation reaction) between a fuel gas containing hydrogen (hydrogen-rich gas) and an oxidant gas such as air containing oxygen. It is a device that generates electric power and heat at the same time.

  Moreover, in order to collect | recover the thermal energy generated at this time, it has the structure which distribute | circulates cooling water to the cooling water flow path of a fuel cell, and collect | recovers heat.

  By the way, when the fuel gas supplied to the anode or the oxidant gas supplied to the cathode contains impurities, the impurities poison the anode or cathode catalyst, or the hydrogen ion conductivity of the electrolyte membrane. There is a problem that the output of the fuel cell and the durability are deteriorated.

  Therefore, in order to suppress a decrease in output and durability of the fuel cell due to impurities contained in the fuel gas or oxidant gas, an impurity removal means is provided, and the impurities contained in the fuel gas or oxidant gas. Was removed and supplied.

  In general, a filter or the like is often used as the impurity removing means, and the impurities are removed by adsorption or separation with the filter. The oxidant gas supplied to the fuel cell often uses air, but the air contains various impurities that affect the output and durability of the fuel cell, such as nitrogen oxides, sulfur compounds, and dust. It can be removed with an acid gas filter or dust filter.

  However, these impurity removal means always remove the impurities by physically or chemically adsorbing and absorbing them during operation, so the lifetime is short and the replacement frequency is increased or the capacity of the filter is reduced. It was necessary to increase (volume).

  Therefore, the conventional fuel cell system includes impurity concentration detection means and flow path switching means. When the impurity concentration exceeds a predetermined value, the impurity removal means (filter) uses the flow path switching means to remove impurities. The flow path is switched so as to be removed, the consumption of the impurity removing means is suppressed, the life is extended, and the replacement frequency is reduced (for example, see Patent Document 1).

Japanese Patent No. 5044755

However, in the method using the conventional impurity concentration detection means, it is necessary to attach an impurity concentration sensor in the middle of the gas path, which not only increases the size of the apparatus, but also a plurality of impurity concentration detection means (sensors) depending on the impurities to be removed. -) Had to be prepared, and had the problem of not being economical.

  Further, in the method using the above conventional impurity concentration detection means, if a concentration slightly higher than the impurity concentration that is the reference for the flow path switching is often detected, it is assumed that the flow path on the impurity removal means side is selected. More than the above, there has been a problem that the lifetime of the impurity removing means is shortened.

  The present invention solves the above-described conventional problems, and does not include an impurity concentration detection means, thereby suppressing the consumption of the impurity removal means, extending the life, and preventing the output of the fuel cell from being reduced in durability. An object is to provide a power generator.

  In order to solve the above-described conventional problems, a fuel cell power generator according to the present invention includes an oxidant gas impurity removing unit that removes impurities contained in an oxidant gas in an oxidant gas supply path. A part of the oxidant gas supplied to the fuel cell is supplied to the fuel cell without passing through the oxidant gas impurity removing means.

  As a result, it is possible to suppress the consumption of the oxidant gas impurity removal means and extend the life without using the impurity concentration detection means.

  The fuel cell power generation device of the present invention can provide a fuel cell power generation device that suppresses a decrease in output and durability of the fuel cell with a relatively inexpensive and simple configuration.

1 is a schematic diagram of a fuel cell system according to Embodiment 1 of the present invention. Sectional drawing which shows typically the oxidizing agent gas impurity removal means accommodating part in Embodiment 1 of this invention The top view which shows typically the oxidizing agent gas impurity removal means accommodating part in Embodiment 1 of this invention Schematic diagram of a fuel cell system in Embodiment 2 of the present invention

  A first invention is a fuel cell power generator comprising an oxidant gas impurity removing means for removing impurities contained in an oxidant gas in an oxidant gas supply path for supplying an oxidant gas to a cathode of a fuel cell. The fuel cell power generator is configured such that a part of the oxidant gas supplied to the fuel cell is supplied to the fuel cell without passing through the oxidant gas impurity removing means.

  With this configuration, in a system that supplies an oxidant gas containing impurities that may affect the output and durability of the fuel cell to the cathode side of the fuel cell, part of the oxidant gas supplied to the fuel cell Since it passes through the oxidant gas impurity removal means and the remainder is supplied to the fuel cell without passing through the oxidant gas impurity removal means, the concentration of impurities entering the fuel cell cathode side can be reduced. In addition, the lifetime of the oxidant gas impurity removal unit can be extended as compared with the case where the total oxidant gas always passes through the oxidant gas impurity removal unit.

In particular, the second invention is the fuel cell power generator according to the first invention, wherein the oxidant gas supply passage includes an oxidant gas impurity removal means accommodating portion for accommodating the oxidant gas impurity removal means, and removes the oxidant gas impurity. The means accommodating portion contains the oxidant gas impurity removing means so that an oxidant gas impurity passage capable of passing through the oxidant gas impurity removing means accommodating portion without passing through the oxidant gas impurity removing means is formed. It is a power generation device.

  With this configuration, the oxidant gas that passes through the oxidant gas impurity removal unit and the oxidant gas that does not pass through the oxidant gas impurity removal unit can be merged with a simple configuration.

  According to a third invention, in particular, in the fuel cell power generator of the first invention, the oxidant gas supply path has two paths, and the oxidant gas impurity removing means is provided in only one of the two paths. It is the fuel cell power generator produced.

  With this configuration, the gas that passes through the oxidant gas impurity removal unit and the gas that does not pass through the oxidant gas impurity removal unit can be clearly separated, and the amount of impurities flowing into the stack can be reliably reduced.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, the present invention is not limited to the embodiments described above. In all of the following drawings, the same or corresponding parts are denoted by the same reference numerals, and redundant description is omitted.

(Embodiment 1)
FIG. 1 is a schematic configuration diagram of a fuel cell system according to a first embodiment of the present invention. FIG. 2 is a cross-sectional view schematically showing the oxidant gas impurity removing unit accommodating portion in the first embodiment of the present invention. FIG. 3 is a plan view schematically showing the oxidant gas impurity removing unit accommodating portion in the first embodiment of the present invention.

  1, the fuel cell system of the present embodiment includes a fuel cell 1, an oxidant gas supply means 2 for supplying an oxidant gas to the cathode of the fuel cell 1, and a fuel gas supply means for supplying a fuel gas to the anode. 3, an oxidant gas impurity removing unit 4 that removes impurities contained in the oxidant gas, an oxidant gas impurity removing unit containing unit 5 that contains the impurity removing unit, an oxidant gas impurity removing unit 4, and impurity removal The gap 6 is formed by a space between the oxidant gas impurity removing means accommodating portion 5 that accommodates the means, an oxidant gas supply path 7, and a fuel gas supply path 8.

  The operation and action of the fuel cell system of the present embodiment configured as described above will be described below.

  The fuel cell 1 is composed of a stack in which a plurality of fuel cell cells composed of an electrolyte membrane made of a solid polymer electrolyte having hydrogen ion conductivity and a cathode and an anode provided so as to sandwich the electrolyte membrane are stacked and fastened. Is done.

  The cathode is formed on one surface of the electrolyte membrane, and includes a catalyst layer made of carbon carrying platinum particles and a polymer electrolyte having hydrogen ion conductivity, and carbon arranged to be laminated on the catalyst layer. It is composed of a conductive gas diffusion layer made of fluororesin.

  The anode is also formed on the other surface of the electrolyte membrane so as to face the cathode, and comprises a catalyst layer comprising carbon carrying platinum ruthenium alloy particles and a polymer electrolyte having hydrogen ion conductivity, and the catalyst layer. It is composed of a conductive gas diffusion layer made of carbon and a fluororesin, which is disposed so as to be laminated.

The electrolyte membrane in which the cathode and the anode are formed is fixed to a resin frame, and the frame is further provided with an oxidant gas channel for supplying an oxidant gas and a fuel gas channel for supplying a fuel gas. A fuel battery cell is configured by being sandwiched between a pair of flat plate separators formed of carbon and resin.

  Here, the materials constituting the electrolyte membrane, the cathode, and the anode are not limited to the materials described above, and are preferably selected as appropriate according to operating conditions and the like.

  The oxidant gas supply means 2 is configured to supply the oxidant gas containing at least oxygen to the cathode of the fuel cell 1 using a blower, a pump, a compressor or the like using the atmosphere as the oxidant gas. Furthermore, in order to adjust the dew point of the oxidant gas to be supplied, a humidifier that performs total heat exchange with the off-oxidant gas discharged from the cathode outlet can be provided. The oxidant gas supply means 2 may be disposed between the oxidant gas impurity removal means accommodating portion 5 and the fuel cell 1.

  The fuel gas supply means 3 is configured to supply a fuel gas containing at least hydrogen to the anode by using a hydrocarbon gas such as city gas as a raw material gas and subjecting the raw material gas to a reforming reaction with water vapor.

  Here, in the atmosphere used as the oxidant gas, in addition to nitrogen oxides and sulfur oxides derived from combustion exhaust gas discharged from automobiles, factories, or household combustion appliances, unburned hydrocarbons and , Volatile organic compounds, impurities such as ammonia and hydrogen sulfide, and other impurities such as particulate matter such as dust may be included. Among these impurities, sulfur compounds, etc. Also included are those that poison the cathode catalyst of the fuel cell 1 and have adverse effects such as reduced output and reduced durability.

  The oxidant gas impurity removing means 4 is configured to be able to remove the above-described various impurities that are included in the oxidant gas and adversely affect the fuel cell 1, and includes an acid gas filter 12, an alkaline gas filter 13, and a dust filter. 11 is provided.

  The dust removal filter 11 can remove particulate impurities such as dust, smog, and smoke. Note that, depending on the design of the oxidant gas impurity removal unit 4, when a general oxidant gas impurity removal unit 4 is used, the impurity concentration contained in the oxidant gas (in the atmosphere) is extremely low. Can be

  For example, impurities having a great influence on the output reduction and durability reduction of the fuel cell 1 such as sulfur compounds contained in the atmosphere can be almost completely removed by passing through the oxidant gas impurity removing means 4. . That is, the impurity concentration in the oxidant gas can be sufficiently reduced as compared with an impurity concentration that does not affect fuel cell power generation, which will be described later.

  The oxidant gas impurity removing means 4 is composed of the acid gas filter 12, the alkaline gas filter 13, and the dust removing filter 11 as described above. Accordingly, combinations can be set within the scope of the present invention. For example, since it is known that sulfur compounds mainly have an adverse effect on fuel cell power generation, a configuration including only the acid gas filter 12 may be employed.

  The oxidant gas impurity removing unit accommodating portion 5 is an outer frame member configured to fix the oxidant gas impurity removing unit 4 and to pass the atmosphere through the oxidant gas impurity removing unit 4. In addition, for example, a part of the oxidant gas may be formed into the oxidant gas by constructing the gap 6 intentionally between the oxidant gas impurity removal unit 4 and the oxidant gas impurity removal unit housing 5. Instead of passing through the impurity removing means 4, the fuel gas can be supplied to the fuel cell 1 through the oxidant gas impurity removing means accommodating portion.

In addition, it is generally known that impurities such as sulfur compounds have an adverse effect on the power generation of the fuel cell when the concentration is high to some extent, but if the concentration is low, the power generation of the fuel cell is not adversely affected. ing. Therefore, for example, in the above-mentioned Patent Document 1, only when the concentration of the impurity exceeds a predetermined value (that is, only when it adversely affects the power generation of the fuel cell), the filter is used for the impurity by using the flow path switching means. The flow path is switched so as to be removed.

  The impurity concentration that does not affect the fuel cell power generation includes, for example, current conditions, gas dew point, gas utilization rate, power generation temperature, start / stop method and other operating conditions, platinum amount of catalyst layer, polymer film thickness, gas diffusion Depends on material conditions, such as gas permeability of the layer. Therefore, it is possible to set an impurity concentration that does not affect fuel cell power generation by simulating an environment in which the fuel cell system is installed experimentally in advance.

  That is, the ratio of the atmosphere that passes through the oxidant gas impurity removing unit 4 and the ratio of the atmosphere that does not pass through the oxidant gas impurity removing unit 4 are set in advance while considering the life of the oxidant gas impurity removing unit 4. Thus, the impurity concentration contained in the oxidant gas supplied to the fuel cell 1 can be set so as not to adversely affect the fuel cell power generation.

  For example, in the case of a sulfur compound which is a typical impurity, when an atmosphere containing a sulfur compound having an average atmospheric concentration of 2 ppb in a certain region is passed through the oxidant gas impurity removal means 4, the sulfur compound concentration is 0. Reduced to 04 ppb.

  Further, for example, when the fuel cell 1 is designed not to be adversely affected by power generation with respect to a sulfur compound of up to 0.5 ppb, the atmosphere passing through the oxidant gas impurity removing unit 4 and the oxidant gas impurity removing unit 4 By designing the gap 6 so that the ratio to the atmosphere that does not pass through is 4: 1, the sulfur compound concentration in the oxidant gas supplied to the fuel cell 1 can be reduced to 0.432 ppb.

  As a result, the life of the oxidant gas impurity removing means can be extended without affecting the fuel cell.

  Note that the above set values are merely examples, and the first embodiment is not limited to the above set values. That is, the concentration of the sulfur compound that is not adversely affected by power generation varies depending on the operating conditions and material conditions of the fuel cell 1. Further, the concentration of the sulfur compound that can be removed varies depending on the design specifications of the oxidant gas impurity removing means 4.

  Therefore, depending on the concentration of the sulfur compound in the environment where the fuel cell system is installed, the specifications of the fuel cell 1 and the specifications of the oxidant gas impurity removal means 4, the atmosphere passing through the oxidant gas impurity removal means 4 and the oxidant gas impurities What is necessary is just to set suitably the ratio with the atmosphere which does not pass the removal means 4. FIG.

  In the conventional method using the impurity concentration detection means, when the concentration slightly higher than the impurity concentration that is the reference for switching the channel is often detected (that is, when the power generation of the fuel cell is adversely affected), the impurity removal means There is a problem that the life of the impurity removing means is shortened because the selection of the flow path on the side increases more than expected and the entire amount of the oxidant gas supplied to the fuel cell passes through the impurity removing means.

  In contrast, in the case of the present invention, part of the oxidant gas supplied to the fuel cell 1 is always supplied to the fuel cell 1 without passing through the oxidant gas impurity removing means 4 during power generation. Therefore, the consumption of the oxidant gas impurity removing means 4 can be suppressed and the life can be extended.

As a method for setting the ratio of the atmosphere that passes through the oxidant gas impurity removing unit 4 and the ratio of the atmosphere that does not pass through the oxidant gas impurity removing unit 4, for example, the oxidant gas impurity removing unit 4 and the oxidant gas are used. This can be realized by appropriately changing the size of the gap 6 provided between the impurity removing means accommodating portions 5.

  In addition, since the pressure loss of the gap 6 is considerably smaller than that of the oxidant gas impurity removing means 4, the ratio of the air passing through the gap 6 may be too large to adjust the flow rate ratio. In this case, for example, by reducing the flow path cross-sectional area of the gap 6 or providing an obstacle in the gap 6 to increase the pressure loss of the gas flowing through the gap 6 as appropriate, the oxidant gas impurity removing means The flow rate ratio with the gas passing through 4 can be easily adjusted.

  As described above, in the present embodiment, a part of the oxidant gas supplied to the fuel cell is configured to be supplied to the fuel cell 1 without passing through the oxidant gas impurity removing means 4. As a result, the concentration of impurities supplied to the fuel cell 1 can be reduced, so that a reduction in the output and durability of the fuel cell can be suppressed.

  In addition, since a part of the oxidant gas can be supplied to the fuel cell 1 without passing through the oxidant gas impurity removal unit 4, consumption of the oxidant gas impurity removal unit 4 can be suppressed. In addition, it is possible to extend the life of the oxidizing gas impurity removal means.

  Further, in the present embodiment, the oxidant gas impurity removing means accommodating portion 5 has an oxidant gas passage that can pass through the oxidant gas impurity removing means accommodating portion 5 without passing through the oxidant gas impurity removing means 4. By being configured to be able to do so, there is no need to divide the system into two paths, an oxidant gas supply path provided with the oxidant gas impurity removal means 4 and an oxidant gas supply path not provided with the oxidant gas impurity removal means 4. The effects of the present invention can be obtained with a relatively simplified configuration.

(Embodiment 2)
FIG. 4 is a schematic configuration diagram of a fuel cell system according to the second embodiment of the present invention.

  4, the fuel cell system of the present embodiment includes a fuel cell 1, an oxidant gas supply means 2 for supplying an oxidant gas to the cathode of the fuel cell 1, and a fuel gas supply means for supplying a fuel gas to the anode. 3, an oxidant gas impurity removal means 4 for removing impurities contained in the oxidant gas, an oxidant gas supply path 7 provided with the oxidant gas impurity removal means 4, a fuel gas supply path 8, An oxidant gas supply path 9 in which the oxidant gas impurity removing means 4 is not provided is provided, and the oxidant gas supply path 7 and the oxidant gas supply path 9 are combined on the upstream side of the fuel cell 1. . The other configuration is the same as that of the first embodiment, and redundant description is omitted.

  With the above configuration, since it is not necessary to provide a gap in the oxidant gas impurity removal unit accommodating portion 5, the design of the oxidant gas impurity removal unit 4 and the oxidant gas impurity removal unit accommodating portion 5 becomes easy, and the fuel cell power generator This contributes to long-term stable operation.

  When the oxidant gas supply means 2 is individually installed in each supply path, the oxidant gas supply path 7 and the oxidant gas are set by setting the gas flow rate value of each oxidant gas supply means 2. It becomes possible to control the ratio (flow rate ratio) of the gas flowing through the supply path 9 more accurately and stably.

In the second embodiment, the oxidant gas supply means 2 is arranged at the inlets (gas supply ports) of the two supply paths, but the present invention is not limited to this. That is, for example, only one oxidant gas supply means 2 may be arranged between the position after the two supply paths merge and the fuel cell 1. In the case of this configuration, the number of oxidant gas supply means 2 can be reduced, and the system configuration is further simplified.

  Also in this configuration, as in the first embodiment, the ratio of the atmosphere passing through the oxidant gas supply path 7 provided with the oxidant gas impurity removal unit 4 and the oxidant gas impurity removal unit 4 are provided. By setting in advance the proportion of the atmosphere that passes through the oxidant gas supply path 9 that is not present, the impurity concentration contained in the oxidant gas supplied to the fuel cell 1 is set to an impurity concentration that does not adversely affect the fuel cell power generation. Can be set.

  For example, in the case of a nitrogen compound that is a typical impurity, when an atmosphere containing a compound having an average atmospheric concentration of 20 ppb in a certain region is passed through the oxidant gas impurity removing means 4, the nitrogen compound concentration is 0.4 ppb. Reduced to

  Further, for example, when the fuel cell 1 is designed so as not to be adversely affected by power generation with respect to nitrogen compounds of up to 8 ppb, the atmosphere passing through the oxidant gas supply path 7 provided with the oxidant gas impurity removing means 4 is provided. And the gas flow rate is adjusted to be 2: 1 so that the ratio to the atmosphere passing through the oxidant gas supply path 9 in which the oxidant gas impurity removing means 4 is not provided is 2: 1. The nitrogen compound concentration in the oxidant gas can be reduced to 6.93 ppb.

  As a result, the life of the oxidant gas impurity removing means can be extended without affecting the fuel cell.

  Note that the above set values are merely examples, and the second embodiment is not limited to the above set values. That is, the nitrogen compound concentration that is not adversely affected by power generation varies depending on the operating conditions and material conditions of the fuel cell 1. Further, the nitrogen compound concentration that can be removed varies depending on the design specifications of the oxidant gas impurity removing means 4.

  Therefore, the oxidant gas supply path in which the oxidant gas impurity removal means 4 is provided depends on the concentration of nitrogen compounds in the environment where the fuel cell system is installed, the specifications of the fuel cell 1, and the specifications of the oxidant gas impurity removal means 4. The ratio of the atmosphere passing through 7 and the atmosphere passing through the oxidant gas supply path 9 where the oxidant gas impurity removing means 4 is not provided may be set as appropriate.

  As described above, in the present embodiment, a part of the oxidant gas supplied to the fuel cell is configured to be supplied to the fuel cell 1 without passing through the oxidant gas impurity removing means 4. As a result, the concentration of impurities supplied to the fuel cell 1 can be reduced, so that a reduction in the output and durability of the fuel cell can be suppressed.

  In addition, since a part of the oxidant gas can be supplied to the fuel cell 1 without passing through the oxidant gas impurity removal unit 4, consumption of the oxidant gas impurity removal unit 4 can be suppressed. In addition, it is possible to extend the lifetime of the oxidizing gas impurity removal means.

  Furthermore, the ratio of the gas flowing through the oxidant gas supply path 7 and the oxidant gas supply path 9 by adding the oxidant gas supply path 9 not provided with the oxidant gas impurity removing means 4 in the present embodiment. It becomes possible to control the (flow rate ratio) more accurately and stably, and it is possible to suppress a decrease in the output and durability of the fuel cell.

As described above, the fuel cell power generation device according to the present invention includes the oxidant gas impurity removal means for removing impurities contained in the oxidant gas in the oxidant gas supply path, and is supplied to the fuel cell. Part of the oxidant gas to be supplied to the fuel cell without passing through the oxidant gas impurity removal means, thereby suppressing consumption of the oxidant gas impurity removal means, Since the service life can be extended, the present invention can be applied to applications such as a fuel cell used as a driving source for a moving body such as an automobile, a distributed power generation system, and a household cogeneration system.

DESCRIPTION OF SYMBOLS 1 Fuel cell 2 Oxidant gas supply means 3 Fuel gas supply means 4 Oxidant gas impurity removal means 5 Oxidant gas impurity removal means accommodation part 6 Crevice 7 Oxidant gas supply path 8 Fuel gas supply path 9 Oxidant gas supply path 11 Dust filter 12 Acid gas filter 13 Alkaline gas filter

Claims (3)

A fuel cell power generator comprising an oxidant gas impurity removing means for removing impurities contained in the oxidant gas in an oxidant gas supply path for supplying an oxidant gas to a cathode of the fuel cell,
A fuel cell power generator configured to supply a part of the oxidant gas supplied to the cathode to the cathode without passing through the oxidant gas impurity removing means.   An oxidant gas impurity removal means accommodating portion for accommodating the oxidant gas impurity removal means is provided in the oxidant gas supply path, and the oxidant gas impurity removal means accommodation portion passes through the oxidant gas impurity removal means. 2. The fuel cell power generator according to claim 1, wherein the oxidant gas impurity removal means is accommodated so that a passage of the oxidant gas that can pass through the oxidant gas impurity removal means accommodation portion is formed.   2. The fuel cell power generator according to claim 1, wherein the oxidant gas supply path has two paths, and the oxidant gas impurity removing unit is provided only in one of the two paths.

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