JP2006286439A - Fuel cell generator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel cell generator that is improved in durability, by removing impurities contained in the oxidizer gas and suppressing deterioration due to impurities. <P>SOLUTION: The fuel cell generator comprises a fuel cell, an oxidizer gas supply means 4, an oxidizer gas purifying means 5 for removing the impurities contained in the oxidizer gas, an oxidizer gas passage switching means 6 which discharges to the atmosphere for a certain time the impurities adsorbed by the oxidizer gas purifying means 5, before starting of power generation, and supplies the oxidizer gas purified by the oxidizer gas purifying means 5 to the fuel cell during power generation, and a heating means 7 for heating the oxidizer gas purifying means 5. Since, among the impurities adsorbed by the oxidant gas purifying means 5, the impurities which have the possibility of being desorbed are heated by the heating means 7, prior to the starting of power generation and are desorbed; and by switching them to the atmosphere side by the oxidizer gas passage switching means 6 and discharging to the atmosphere, the oxidizer gas, which contains no impurities, is supplied to the fuel cell at power generation, thereby the durability of the fuel cell generator can be improved. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a fuel cell power generator that suppresses a decrease in voltage of a fuel cell due to impurities contained in an oxidant gas or improves durability.

  The configuration and operation of a conventional general solid polymer electrolyte fuel cell will be described with reference to FIG. In FIG. 3, reference numeral 1 denotes a solid polymer electrolyte made of perfluorocarbon sulfonic acid having hydrogen ion conductivity. An anode 21 and a cathode 22 are formed as a pair of electrodes on both surfaces of the electrolyte 1. The anode 21 and the cathode 22 have a catalyst layer made of a mixture of a catalyst in which a noble metal such as platinum is supported on porous carbon and a polymer electrolyte having hydrogen ion conductivity, and air permeability and electronic conductivity laminated on the catalyst layer. A gas diffusion layer having a property is provided. A pair of gaskets for preventing gas mixing and leakage are disposed around the anode 21 and the cathode 22, a fuel gas containing at least hydrogen is supplied to and discharged from the anode 21, and an oxidizing agent containing at least oxygen is supplied to the cathode 22. It is sandwiched between a pair of conductive separator plates 31 and 32 having gas flow paths for supplying and discharging gas.

  A stack obtained by laminating a plurality of single cells having the above configuration is referred to as a stack, and the single cell or the stack is collectively referred to as a fuel cell.

  When the fuel gas and the oxidant gas are supplied to the anode 21 and the cathode 22, respectively, and an electronic load is connected, the hydrogen contained in the fuel gas supplied to the anode 21 releases electrons at the interface between the anode 21 and the electrolyte 1 to generate hydrogen. It becomes an ion (Chemical formula 1).

(Chemical formula 1)
H ₂ → 2H ⁺ + 2e ⁻
The hydrogen ions move to the cathode 22 through the electrolyte 1, receive electrons at the interface between the cathode 22 and the electrolyte 1, react with oxygen contained in the oxidant gas supplied to the cathode 22, and generate water ( 2).

(Chemical formula 2)
1 / 2O ₂ + 2H ⁺ + 2e ⁻ → H ₂ O
The total reaction is shown in (Chemical Formula 3).

(Chemical formula 3)
H ₂ + 1 / 2O ₂ → H ₂ O
At this time, the flow of electrons flowing through the electronic load can be used as DC electrical energy. Further, since the series of reactions is an exothermic reaction, reaction heat and generated Joule heat can be used as heat energy.

  The fuel gas is supplied by reforming the raw material gas. The raw material gas is supplied to the desulfurization section, and sulfur compounds contained in the odorant and the like are removed by adsorption (desulfurization). Then, it is reformed in the fuel processing unit to become a fuel gas containing hydrogen, and is supplied to the anode 21 of the fuel cell. The fuel processing unit includes a reformer that reforms methane and the like, a CO converter that converts generated carbon monoxide (CO), and a CO remover that further removes CO.

  When methane is used as the source gas, in the reformer, the reaction shown in (Chemical Formula 4) occurs with water vapor, and about 10% of CO is generated together with hydrogen.

(Chemical formula 4)
CH ₄ + H ₂ O → CO + 3H ₂
Thereafter, the generated CO is oxidized to carbon dioxide by a CO converter as shown in (Chemical Formula 5) and reduced to about 5000 ppm. Since the downstream CO remover oxidizes not only CO but also hydrogen of the fuel gas, it is necessary to reduce the CO concentration as much as possible with the CO converter.

(Chemical formula 5)
CO + H ₂ O → CO ₂ + H ₂
Further, the remaining CO is oxidized by reacting with oxygen contained in the air in the CO remover as shown in (Chemical Formula 6), and its concentration is reduced to about 10 ppm or less.

(Chemical formula 6)
CO + 1 / 2O ₂ → CO ₂
The overall reaction formula is shown in (Chemical Formula 7).

(Chemical formula 7)
CH ₄ + 2H ₂ O → CO ₂ + 4H ₂
Since platinum contained in the anode 21 is poisoned by CO and its catalytic activity deteriorates in the operating temperature range of the fuel cell, a catalyst having resistance to CO such as platinum-ruthenium is usually used for the anode 21.

  In addition, when impurities are present in the oxidant gas, the output voltage of the fuel cell is lowered due to the impurities. For example, when an organic substance such as toluene contained in paint or the like is mixed into the cathode 22 as an impurity, the fuel cell temporarily reacts with oxygen contained in the oxidant gas on the catalyst to inhibit the reaction with hydrogen. Output voltage drops. Moreover, when sulfur compounds such as sulfur dioxide contained in exhaust gas and hydrogen sulfide contained in a lot of hot springs are mixed as impurities, platinum contained in the cathode 22 is poisoned and the catalytic activity is deteriorated. . Moreover, when ammonia which is offensive odor is mixed, the acidic electrolyte is neutralized and the ionic conductivity of the electrolyte is lowered. Further, when dust such as atmospheric dust is mixed in the oxidant gas, the gas flow paths of the separators 31 and 32, the gas diffusion layer, and the like are clogged, so that the gas diffusion is inhibited and the voltage temporarily decreases. Sometimes. Therefore, it is necessary to remove impurities that adversely affect the fuel cell contained in the oxidant gas.

Conventionally, for example, impurities contained in air are adsorbed and removed by adsorbent particles such as activated carbon held in a three-dimensional structure using a binder or the like (see Patent Document 1).
JP 2003-297410 A

  However, in the conventional method of adsorbing and removing impurities on adsorbent particles such as activated carbon, volatile organic substances such as toluene once adsorbed on the adsorbent are desorbed from the adsorbent due to environmental temperature changes, etc. There existed a subject that it mixes in an oxidizing agent gas as an impurity and reduces battery voltage temporarily.

  The present invention solves the above-mentioned conventional problems, and discharges impurities adsorbed on the oxidant gas purification means to the atmosphere for a predetermined time before starting power generation, and the oxidant gas purified by the oxidant gas purification means during power generation. By providing oxidant gas flow path switching means for supplying the fuel cell to the fuel cell and heating means for heating the oxidant gas purification means, it is possible to prevent a temporary drop in battery voltage due to desorption of impurities such as volatile organic substances, and to be durable An object of the present invention is to provide a fuel cell power generator excellent in performance.

  In order to solve the conventional problem, the fuel cell power generator of the present invention exhausts impurities adsorbed to the oxidant gas purification means to the atmosphere for a certain period of time before starting the power generation of the fuel cell, and the oxidant gas during power generation. It comprises an oxidant gas flow path switching means for supplying the oxidant gas purified by the purification means to the fuel cell, and a heating means for heating the oxidant gas purification means.

  As a result, impurities such as volatile organic substances that may be desorbed due to environmental temperature changes, etc. are heated by the heating means before the power generation of the fuel cell is started and desorbed by the oxidant gas purification means, and the oxidant gas flow path is switched. The means can be switched and discharged to the atmosphere, and a decrease in battery voltage during power generation due to these impurities can be suppressed.

  As described above, according to the fuel cell power generation device of the present invention, even if impurities such as volatile organic substances that may be desorbed exist in the oxidant gas, these impurities are released into the atmosphere before power generation is started. Since it discharges | emits, the fall of the output voltage of a fuel cell can be suppressed, and the fuel cell power generator excellent in durability can be provided.

  A first invention is a gas flow path for supplying and discharging an electrolyte, a pair of electrodes sandwiching the electrolyte, and supplying and discharging a fuel gas containing at least hydrogen to one of the electrodes, and an oxidant gas containing at least oxygen to the other of the electrodes A fuel cell comprising at least one cell having a pair of separator plates, an oxidant gas supply means for supplying the oxidant gas, and an oxidant gas purification means for removing impurities contained in the oxidant gas. The oxidant gas flow that discharges impurities adsorbed to the oxidant gas purification means to the atmosphere for a predetermined time before power generation is started and supplies the oxidant gas purified by the oxidant gas purification means to the fuel cell during power generation. A path switching unit and a heating unit that heats the oxidant gas purification unit, and out of impurities adsorbed on the oxidant gas purification unit, impurities that may be desorbed are heated before power generation is started. The oxidant gas purifying means is heated and desorbed, the oxidant gas flow path switching means is switched to the atmosphere side, discharged to the atmosphere, and the oxidant gas containing no impurities is supplied to the fuel cell during power generation. The durability of the fuel cell power generator can be improved.

  Also, by heating the oxidant gas purification means with the heating means to facilitate the desorption of the adsorbed impurities, the adsorption site of the oxidant gas purification means is activated and the oxidant gas purification means can be regenerated. Thus, the life of the oxidant gas purification means can be extended.

  The second aspect of the invention is particularly during power generation by switching the oxidant gas flow path switching means of the first aspect of the invention so that the impurities adsorbed on the oxidant gas purification means are discharged to the atmosphere for a certain time even when power generation is stopped. Among the impurities adsorbed on the oxidant gas purification means, impurities that may be desorbed are desorbed when the power generation is stopped and discharged to the atmosphere, and impurities that could not be desorbed when the power generation was stopped before the power generation was started, Impurities that have been adsorbed can be desorbed and discharged to the atmosphere, and the oxidant gas purification means is regenerated and oxidant gas that does not contain impurities is supplied to the fuel cell the next time power is generated. The durability of the battery power generator can be improved.

  In the third aspect of the invention, in particular, the heating means of the first aspect of the invention heats the oxidant gas purification means for a certain period of time before starting power generation, and then stops and cools the heating of the oxidant gas purification means, Impurities adsorbed on the oxidant gas purification means can be easily desorbed, and the oxidant gas purification means can be regenerated in a short time.

  Moreover, since it can reproduce | regenerate in a short time, the energy required for an oxidant gas supply means to supply oxidant gas can be reduced, and the efficiency of electric power generation can be improved.

  In the fourth aspect of the invention, in particular, the heating means of the first aspect of the invention is adsorbed to the oxidant gas purification means using the remaining heat after the power generation is stopped by heating the oxidant gas purification means for a certain time when the power generation is stopped. Impurities can be desorbed and discharged to the atmosphere, and the oxidant gas purification means is regenerated, and the oxidant gas that does not contain impurities is supplied to the fuel cell when power is next generated. Can be improved.

  The fifth invention is particularly characterized in that the heating means of the first invention uses at least one of an electric heater, cooling water, fuel cell off-gas, air and combustion exhaust gas. A heating supply source can be provided in the system of the apparatus, and the energy efficiency of the entire system can be improved.

  In particular, the oxidant gas purifying means of the first invention has an activated carbon filter including activated carbon that adsorbs organic matter contained in the oxidant gas, and the activated carbon has a large specific surface area, such as organic matter. By efficiently adsorbing and heating the impurity gas, the adsorbed impurity gas can be desorbed and regenerated, and the oxidant gas containing impurities is purified and supplied to the fuel cell. It is possible to suppress a decrease in voltage and improve durability.

  In the seventh invention, in particular, the oxidizing gas purification means of the first invention has an alkaline gas removal filter including activated carbon impregnated with an acid that adsorbs or absorbs alkaline gas, and adsorbs impurities such as organic substances with activated carbon. In addition to removing it, it can adsorb or absorb an alkaline gas such as ammonia, which is a malodorous component, and can suppress a decrease in battery voltage and deterioration of the film due to an alkaline impurity gas such as ammonia. The durability of the fuel cell power generator can be improved.

  In the eighth invention, in particular, the oxidant gas purification means of the first invention has an acidic gas removal filter including activated carbon impregnated with an alkali that adsorbs or absorbs acidic gas, and adsorbs impurities such as organic substances with activated carbon. In addition, it can adsorb or absorb acidic gases such as nitrogen oxides and sulfur oxides contained in exhaust gas and hydrogen sulfide generated in hot springs. It is possible to suppress electrode deterioration due to reduction or poisoning of a catalyst such as platinum, and to improve the durability of the fuel cell power generator.

  In the ninth aspect of the invention, in particular, the oxidizing gas purification means of the first aspect of the invention includes a pre-filter for removing dust, an alkaline gas removal filter for removing alkaline gas, an acidic gas removal filter for removing acidic gas, Equipped with a dust removal filter that removes dust and removes various impurities contained in the oxidant gas, so it is possible to suppress battery voltage drop and fuel cell degradation due to these impurities, and durability of the fuel cell power generator Can be improved.

  According to a tenth aspect of the invention, in particular, the oxidizing gas purifying means of the first or ninth aspect comprises a spacer between the acidic gas removal filter and the alkaline gas removal filter, and the alkaline acidic gas removal filter and the acidic gas removal means are provided. Therefore, it is possible to prevent deterioration of the removal performance of each filter due to neutralization.

  Embodiments of the present invention will be described below with reference to the drawings. Note that the present invention is not limited to the embodiment.

(Embodiment 1)
FIG. 1 shows a configuration diagram of a fuel cell power generator according to the present invention. In FIG. 1, reference numeral 1 denotes a membrane-shaped solid polymer electrolyte made of a perfluorocarbon sulfonic acid polymer having hydrogen ion conductivity. A pair of electrodes, an anode 21 and a cathode 22 are formed on both surfaces of the electrolyte 1. When the electrolyte 1 takes in moisture, the hydrogen ions of the sulfonic acid groups in the electrolyte 1 are dissociated to become charge carriers, and the electrolyte 1 passes through a reverse micelle structure formed by aggregation of several sulfonic acid groups. Shows hydrogen ion conductivity. Since the electrical conductivity of the electrolyte 1 decreases when the water content decreases, a method of preventing the drying of the electrolyte 1 film by supplying the gas with humidification was adopted.

  The anode 21 and the cathode 22 have a catalyst layer made of a mixture of a catalyst in which a noble metal such as platinum is supported on porous carbon and a polymer electrolyte having hydrogen ion conductivity, and air permeability and electronic conductivity laminated on the catalyst layer. It consists of a gas diffusion layer having properties. For the anode 21, an alloy catalyst such as platinum-ruthenium having CO resistance was used. Moreover, carbon paper or carbon cloth subjected to water repellent treatment was used for the gas diffusion layer.

  A pair of gaskets for preventing gas mixing and leakage are arranged around the anode 21 and the cathode 22, respectively, and further, gas flow paths for supplying and discharging fuel gas and oxidant gas to the anode 21 and the cathode 22, respectively. The pair of conductive separator plates 31 and 32 having the pair was sandwiched. The voltage generated by the single cell configured as described above is about 0.75 V, and a plurality of single cells corresponding to the required voltage can be stacked in series to form a fuel cell with a desired output. it can.

  In addition, current collector plates, insulating plates, and end plates were disposed at both ends of the separator plates 31 and 32 and fixed with fastening rods. And it was set as the structure which can detect the voltage of a fuel cell when an electronic load and a voltage detection part are connected to the current collecting plate, and a fixed electric current is sent.

  In addition, a reformer for reforming desulfurized methane, ethane, propane and butane as a main component such as city gas 13A, a CO converter for transforming generated CO, and a CO remover for further removing the remaining CO And a fuel gas containing hydrogen gas generated by the reforming reaction is supplied to the fuel cell.

  The fuel cell power generator of the present invention is installed in ordinary households, stores, factories, etc., but various organic impurity gases generated from solvents, paints, building materials, etc. exist in the atmosphere of such an environment. ing. Many of these can be physically adsorbed by an adsorbent such as activated carbon, but generally they are highly volatile, so they may be desorbed by the ambient temperature at which the fuel cell starts and stops, and the adsorbed organic impurity gases may be desorbed. There is.

  In the embodiment of the present invention, the oxidant gas is taken from the oxidant gas supply means 4 such as a fan, a pump and an air blower from the atmosphere, and is supplied at a predetermined flow rate by the flow rate control means. The oxidant gas purification means 5 disposed between the inlets of the cathode 22 purifies various impurities contained in the oxidant gas and then supplies them to the cathode 22 of the fuel cell. 5, an oxidant gas flow path switching unit 6 that desorbs the organic impurity gas adsorbed on 5 and discharges it to the atmosphere before starting power generation, and a heating unit that promotes desorption of the organic impurity gas adsorbed on the oxidant gas purification unit 5. 7 was placed.

  According to the above configuration, of the impurities adsorbed on the oxidant gas purification means 5, impurities that may be desorbed are heated by the heating means 7 before the start of power generation and desorbed from the oxidant gas purification means 5, thereby The gas flow path switching means 6 is switched to the atmosphere side, discharged to the atmosphere, and an oxidant gas containing no impurities is supplied to the fuel cell during power generation, so that the durability of the fuel cell power generator can be improved. it can.

  Further, the oxidant gas purification means 5 is heated by the heating means 7 so that the adsorbed impurities are easily desorbed, whereby the adsorption site of the oxidant gas purification means 5 is activated, and the oxidant gas purification means 5 is activated. It can be regenerated and the life of the oxidant gas purification means 5 can be extended. Moreover, since the oxidant gas purification means 5 can be regenerated in a short time by heating, the energy required for the oxidant gas supply means 4 to supply the oxidant gas can be reduced, and the power generation efficiency can be reduced. Can be improved.

  Furthermore, according to the embodiment of the present invention, the remaining heat after power generation is stopped, and the oxidant gas flow path switching unit 6 discharges impurities adsorbed on the oxidant gas purification unit 5 to the atmosphere for a certain period of time even when power generation is stopped. By switching so that impurities that are adsorbed to the oxidant gas purification means 5 during power generation are desorbed when the power generation is stopped and discharged to the atmosphere. Impurities that could not be exhausted and impurities that were adsorbed during stoppage can be desorbed and discharged to the atmosphere. When the oxidant gas purification means 5 is regenerated and the next power generation, the fuel cell contains impurities. Since the oxidant gas is supplied, the durability of the fuel cell power generator can be improved.

  The heating means 7 of the embodiment of the present invention uses an electric heater, but besides the electric heater, at least one of cooling water for cooling the stack, fuel cell off-gas, heat-exchanged air, and combustion exhaust gas is used. Since the heating supply source is provided within the fuel cell power generation system, the energy efficiency of the entire system can be increased.

  In addition to organic impurity gases, the atmosphere emits ammonia, hydrogen sulfide, sulfur dioxide and nitrogen dioxide contained in exhaust gas from automobiles, etc., from plants, etc. There may be various impurities such as hydrogen chloride and hydrogen fluoride.

  In the embodiment of the present invention, the oxidant gas purification means 5 includes a prefilter that removes particulate matter such as dust contained in the atmosphere, and particulate matter such as dust generated from the oxidant gas supply means. , Acid gas removal filters that remove acidic impurities such as hydrogen sulfide, sulfur dioxide, nitrogen dioxide, hydrogen chloride, and hydrogen fluoride, and alkaline impurities such as ammonia and trimethylamine that may be present in the atmosphere Alkaline gas removal filter, particulate matter such as dust contained in the atmosphere, dust removal filter that removes particulate matter such as dust generated from acid gas removal filter and alkaline gas removal filter in the previous stage, and acid gas removal It consists of a spacer provided so that the filter does not come into contact with the alkaline gas removal filter. Luo filter, is housed in a casing, which is a pipe to direct the clean air to the cathode 22.

  In addition, a buffer material was provided around the acid gas removal filter, the alkaline gas removal filter, and the dust removal filter, and the buffer material was stored in the housing via the buffer material. Thereby, airtightness improves, the leak of the impurity which arises because the oxidant gas to process flows around from the filter periphery can be prevented, and the removal performance of various filters can be improved.

  The spacer was made of a material such as a resin that does not corrode, and a vent was formed so as not to increase pressure loss. In addition, since the spacer does not contact the acid gas removal filter and the alkaline gas removal filter, the alkali attached to the acid gas removal filter and the acid attached to the alkaline gas removal filter cause a neutralization reaction and the mutual removal performance deteriorates. Can be prevented.

  The oxidant gas taken in from the atmosphere first passes through the pre-filter, then passes through the acid gas removal filter and spacer, passes through the alkaline gas removal filter, and finally passes through the dust removal filter. Reduce concentration.

  As the prefilter, a fiber made of polypropylene or the like was charged and then woven into a nonwoven fabric. The prefilter removes not only dust in which each of the electrostatically charged fibers is contained in the oxidant gas, but also dust and particulate matter generated from the oxidant gas supply means 4 arranged in the preceding stage. In addition to maintaining the removal performance of the acid gas removal filter and alkaline gas removal filter, the load of the dust removal filter is reduced, so the life of the dust removal filter can be extended.

  The acid gas removal filter was obtained by using calcium hydroxide as an alkali that absorbs acidic impurities, kneading activated carbon and a curing agent, granulating, and molding into a honeycomb type. Calcined gypsum was used as the curing agent. When calcined gypsum is mixed with water, it becomes calcium sulfate and hardens. Calcium hydroxide reacts with acidic impurities such as nitrogen dioxide and sulfur dioxide as shown in (Chemical Formula 8) and (Chemical Formula 9), respectively, to fix calcium nitrate and calcium sulfate on the filter and chemically adsorb them.

(Chemical Formula 8)
4NO ₂ + 2Ca (OH) ₂ → Ca (NO ₂ ) ₂ + Ca (NO ₃ ) ₂ + H ₂ O
(Chemical 9)
SO ₂ + Ca (OH) ₂ → CaSO ₄ · 1 / 2H ₂ O + 1 / 2H ₂ O
Therefore, instead of simply adsorbing, impurities and alkali are reacted and fixed on the filter, so there is no desorption depending on the concentration or temperature, and the desorbed high-concentration impurities are mixed into the fuel cell. Can be prevented from deteriorating. Moreover, since porous activated carbon is used, organic solvents, such as toluene, methyl ethyl ketone, and trichloroethylene, can also be adsorbed, and the deterioration of battery performance due to these impurities can be suppressed. In addition, the reaction area can be increased by using a honeycomb structure. In addition, the pressure loss due to the filter of the oxidant gas to be introduced can be reduced, and the clogging of the filter can be suppressed, so that the load of the oxidant gas supply means 4 is not affected and the power generation efficiency is kept high. be able to.

  For the alkaline gas removal filter, a fibrous activated carbon sheet was impregnated with a phosphoric acid solution adjusted to a certain concentration as an absorbent for alkaline impurities, separated and dried, and the sheet was further processed into a corrugated type. Phosphoric acid is fixed on the surface of the activated carbon fiber, and ammonium phosphate generated by reacting with an alkaline impurity such as ammonia as shown in (Chemical Formula 10) is fixed on the surface of the activated carbon fiber and chemically adsorbed.

(Chemical formula 10)
NH ₃ + H ₃ PO ₄ → (NH ₄ ) ₃ PO ₄
Therefore, it does not simply adsorb, but reacts with impurities and adhering substances and is fixed on the filter, so there is no desorption depending on the concentration or temperature, and the desorbed impurities are mixed into the fuel cell, degrading cell performance. Can be prevented. Moreover, since porous activated carbon is used, organic solvents, such as toluene, methyl ethyl ketone, and trichloroethylene, can also be adsorbed, and the deterioration of battery performance due to these impurities can be suppressed. Further, by using fibrous activated carbon, not only can the weight be reduced, but the degree of freedom in shape and size can be increased, and breakage such as cracks and cracks can be eliminated. In addition, the reaction area can be increased by using a corrugated structure. In addition, the pressure loss due to the filter of the oxidant gas to be introduced can be reduced and the clogging of the filter is suppressed, so that the load on the oxidant gas supply means 4 etc. is not affected and the power generation efficiency is kept high. can do.

  The dust removal filter was prepared by charging a fiber made of polypropylene or the like, then increasing the basis weight of the prefilter to form a woven nonwoven fabric in a pleated shape and fixing it to a frame. Each electrostatically charged fiber attracts and adsorbs microscopic dust suspended in the air by the action of Coulomb force and induced force, so particulate matter such as dust in the atmosphere and acid gas removal filter in the previous stage Particulate matter such as dust generated from the alkaline gas removal filter itself can be efficiently removed.

  With the above filter configuration, various organic gas impurities that may exist in the atmosphere, alkaline impurities such as ammonia and trimethylamine, acidic impurities such as hydrogen sulfide, sulfur dioxide, nitrogen dioxide, hydrogen chloride, and hydrogen fluoride, and the atmosphere Removes particulate impurities such as dust contained in the fuel cell to prevent its entry into the fuel cell, preventing poisoning of the catalyst and ion conductivity due to these impurities, and suppressing a decrease in battery voltage. be able to.

  Further, the ventilation resistance of the entire filter is very small, the pressure loss due to the filter is about 100 Pa, and the power generation efficiency can be kept high without affecting the load of the oxidant gas supply means 4 and the like.

  When the fuel cell power generation apparatus having the above configuration is used, the organic impurity gas desorbed from the oxidant gas purification means 5 by the heating means 7 is not supplied to the cathode 22 of the fuel cell by using the oxidant gas flow path switching means 6. The behavior of the voltage was confirmed when supplied.

  First, before the power generation is started, the electric heater of the heating means 7 is energized to heat the oxidant gas purification means 5 for a certain period of time to desorb the adsorbed organic impurity gas, and the oxidant gas flow path switching means 6 is set to the atmosphere. Switching to the exhaust side, the atmosphere was introduced by the oxidant gas supply means 4, and the desorbed organic impurity gas was released to the atmosphere. The heating means 7 was stopped and cooled after heating for a certain time.

Next, the oxidant gas flow path switching means 6 is switched to the cathode 22 side, the ambient temperature of the fuel cell power generator actually used is assumed, the heating means 7 that is originally stopped is operated, and the oxidant gas The temperature of the gas purification means 5 was raised, and the oxidant gas was humidified and supplied to the cathode 22 in a predetermined amount. A fuel gas containing about 20% carbon dioxide is supplied to the anode 21 so that the cell temperature is about 70 ° C., the fuel gas utilization rate is about 75%, and the oxidant gas utilization rate is about 40%. On the other hand, when a constant current of about 0.2 A / cm ² was passed, the cell voltage detected by the voltage detector connected to the fuel cell was stable at about 0.75 V.

  On the other hand, heating before starting power generation is stopped, the oxidant gas purification means 5 on which the organic impurity gas is adsorbed is heated in the same manner, and the oxidant gas flow path switching means 6 is set to the cathode 22 side to generate power again. The voltage oscillated greatly and the battery voltage dropped to about 0.74 V at the maximum. The test results are shown in FIG. From FIG. 2, it was found that by reducing the organic impurity gas adsorbed to the oxidant gas purification means 5 by the heating means 7 before starting the power generation, it is possible to suppress a decrease in voltage and vibration due to the organic impurity gas during power generation.

  The fuel cell power generator of the present invention has an effect of suppressing deterioration due to impurities or improving durability, and is useful for a power generator and a device using a polymer solid electrolyte membrane.

  Moreover, it is useful for a stationary fuel cell cogeneration system installed outdoors where impurities such as bad odor and exhaust gas may exist.

1 is a schematic configuration diagram of a fuel cell power generator according to an embodiment of the present invention. Battery voltage characteristics of the device Schematic configuration diagram of a conventional fuel cell power generator

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Electrolyte 4 Oxidant gas supply means 5 Oxidant gas purification means 6 Oxidant gas flow path switching means 7 Heating means 21 Electrode (anode)
22 electrode (cathode)
31, 32 Separator plate

Claims (10)

A pair of separator plates having an electrolyte, a pair of electrodes sandwiching the electrolyte, and a gas flow path for supplying and discharging a fuel gas containing at least hydrogen to one of the electrodes and supplying and discharging an oxidant gas containing at least oxygen to the other A fuel cell comprising at least one cell, oxidant gas supply means for supplying the oxidant gas, oxidant gas purification means for removing impurities contained in the oxidant gas, and Oxidant gas flow path switching means for discharging impurities adsorbed on the oxidant gas purification means to the atmosphere for a certain period of time, and supplying the oxidant gas purified by the oxidant gas purification means to the fuel cell during power generation, A fuel cell power generator comprising heating means for heating the oxidant gas purification means. 2. The fuel cell power generator according to claim 1, wherein the oxidant gas flow path switching unit discharges impurities adsorbed by the oxidant gas purification unit to the atmosphere for a predetermined time when power generation is stopped. 2. The fuel cell power generator according to claim 1, wherein the heating unit heats the oxidant gas purification unit for a predetermined time before power generation is started, and then stops the heating of the oxidant gas purification unit and cools it. The fuel cell power generator according to claim 1, wherein the heating means heats the oxidant gas purification means for a predetermined time when power generation is stopped. 2. The fuel cell power generator according to claim 1, wherein the heating means uses at least one of an electric heater, cooling water, off-gas of the fuel cell, air, and combustion exhaust gas. The fuel cell power generator according to claim 1, wherein the oxidant gas purification means includes an activated carbon filter including activated carbon that adsorbs organic substances contained in the oxidant gas. The fuel cell power generator according to claim 1, wherein the oxidant gas purification means includes an alkaline gas removal filter including activated carbon impregnated with an acid that adsorbs or absorbs the alkaline gas. The fuel cell power generator according to claim 1, wherein the oxidant gas purification means includes an acid gas removal filter including activated carbon impregnated with an alkali that adsorbs or absorbs the acid gas. The oxidant gas purification means includes a pre-filter for removing dust, an alkaline gas removal filter for removing alkaline gas, an acid gas removal filter for removing acid gas, and a dust removal filter for removing dust. The fuel cell power generator described in 1. The fuel cell power generator according to claim 1 or 9, wherein the oxidant gas purification means includes a spacer between the acid gas removal filter and the alkaline gas removal filter.

Images