JP2008210629A - Fuel cell system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel cell system capable of suppressing occurrence of incomplete combustion therein, and reducing discharge amount of carbon monoxide. <P>SOLUTION: The fuel cell system has a fuel cell 1, a fuel supplying means 2 for regulating an amount of fuel supplied to the fuel cell 1, an oxygen-containing gas supplying means 3 for regulating an amount of oxygen-containing gas supplied to the fuel cell 1, an electric-power regulating means 12 for supplying an electric power generated by the fuel cell 1 to an external load, and a controller 14 for controlling the fuel supplying means 2 and the oxygen-containing gas supplying means 3 in accordance with the required electric power from the external load. The controller 14 controls each of the oxygen-containing gas supplying means 3 and the fuel supplying means 2 so as to increase the fuel supplying amount to the fuel cell 1 after the oxygen-containing gas is increased to supply it to the fuel cell 1, when the required electric power is increased to supply it to the external load. Accordingly, the incomplete combustion is suppressed in the fuel cell 1 to reduce the discharge amount of CO. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a fuel cell device including a control unit that controls an oxygen-containing gas and a fuel gas supplied to the fuel cell.

  In recent years, as a next-generation energy, a fuel cell (module) capable of obtaining electric power using hydrogen (fuel) and air (oxygen-containing gas), and auxiliary equipment for operating the fuel cell are provided in an outer case. Various fuel cell devices housed in the battery and their operating methods have been proposed.

As such a fuel cell device, for example, a fuel supply unit for supplying fuel to the fuel cell and an oxygen-containing gas supply unit for supplying oxygen-containing gas to the fuel cell, and a request for an external load are provided. There has been proposed a fuel cell device provided with control means for controlling the supply amount of fuel and oxygen-containing gas in accordance with the amount of electric power (see, for example, Patent Document 1).
JP 2005-285433 A

  By the way, for example, when the required power amount of the external load changes, when supplying the fuel and the oxygen-containing gas to the fuel cell, there is a deviation in the timing of supplying them, and the fuel supply amount and the oxygen-containing gas supply temporarily In some cases, the amount ratio was out of a certain range. Similarly, when the fuel cell is started or stopped, the ratio between the fuel supply amount and the oxygen-containing gas supply amount may temporarily fall outside a certain range.

  In this case, for example, when the amount of oxygen-containing gas is small relative to the amount of fuel, there is a risk of incomplete combustion in the combustion of the fuel and oxygen-containing gas. At that time, the amount of carbon monoxide (CO) emitted Could increase.

  Accordingly, an object of the present invention is to provide a fuel cell device capable of suppressing the occurrence of incomplete combustion and reducing the emission amount of carbon monoxide.

  The fuel cell apparatus of the present invention includes a fuel cell, fuel supply means for adjusting the amount of fuel in the fuel cell, and oxygen-containing gas supply means for adjusting the amount of oxygen-containing gas supplied to the fuel cell. A power adjusting means for supplying power generated by the power generation of the fuel cell to an external load, and a control for controlling the fuel supply means and the oxygen-containing gas supply means in accordance with the required power amount of the external load And when the required power amount of the external load increases, the control device increases the supply amount of the oxygen-containing gas supplied to the fuel cell, and then increases the supply amount of fuel to the fuel cell. The oxygen-containing gas supply means and the fuel supply means are controlled so as to increase them, respectively.

  In such a fuel cell device, in the fuel cell device that performs the load following operation according to the required power amount of the external load, when the required power amount of the external load increases, the oxygen-containing gas supply means and the fuel supply means are After controlling and increasing the supply amount of the oxygen-containing gas supplied to the fuel cell, the supply amount of fuel to the fuel cell is increased.

  As a result, the ratio of the fuel supply amount and the oxygen-containing gas supply amount in the fuel cell can be suppressed from being out of a certain range, and the occurrence of incomplete combustion in the fuel cell can be suppressed to reduce CO emissions. can do.

  The fuel cell apparatus of the present invention includes a fuel cell, fuel supply means for adjusting the amount of fuel in the fuel cell, and oxygen-containing gas supply means for adjusting the amount of oxygen-containing gas supplied to the fuel cell. A power adjusting means for supplying power generated by the power generation of the fuel cell to an external load, and a control device for controlling the fuel supply means and the oxygen-containing gas supply means in accordance with the required power amount of the external load When the required power amount of the external load decreases, the control device decreases the supply amount of the fuel supplied to the fuel cell, and then decreases the supply amount of the oxygen-containing gas to the fuel cell. The oxygen-containing gas supply means and the fuel supply means are controlled respectively.

  In such a fuel cell device, in the fuel cell device that performs load following operation according to the required power amount of the external load, when the required power amount of the external load decreases, the oxygen-containing gas supply means and the fuel gas supply means Is controlled to reduce the amount of fuel supplied to the fuel cell, and then the amount of oxygen-containing gas supplied to the fuel cell is decreased.

  Thereby, it is possible to suppress the ratio of the fuel supply amount and the oxygen-containing gas supply amount from being out of a certain range, thereby suppressing the occurrence of incomplete combustion in the fuel cell and reducing the CO emission amount. it can.

  The fuel cell apparatus of the present invention includes a fuel cell, fuel supply means for adjusting the amount of fuel in the fuel cell, and oxygen-containing gas supply means for adjusting the amount of oxygen-containing gas supplied to the fuel cell. A power adjusting means for supplying power generated by the power generation of the fuel cell to an external load, and a control device for controlling the fuel supply means and the oxygen-containing gas supply means in accordance with the required power amount of the external load And the control device starts the supply of fuel to the fuel cell after starting the supply of the oxygen-containing gas to the fuel cell when the fuel cell is started. The contained gas supply means and the fuel supply means are respectively controlled.

  In such a fuel cell apparatus, when the fuel cell is started, the oxygen-containing gas supply means and the fuel supply means are controlled, and after the supply of the oxygen-containing gas to the fuel cell is started, the fuel is supplied to the fuel cell. Start supplying.

  Thereby, at the time of starting the fuel cell, the ratio of the fuel supply amount and the oxygen-containing gas supply amount can be suppressed from being out of a certain range, and the occurrence of incomplete combustion in the fuel cell can be suppressed. Can be reduced.

  The fuel cell apparatus of the present invention includes a fuel cell, fuel supply means for adjusting the amount of fuel in the fuel cell, and oxygen-containing gas supply means for adjusting the amount of oxygen-containing gas supplied to the fuel cell. A power adjusting means for supplying power generated by the power generation of the fuel cell to an external load, and a control device for controlling the fuel supply means and the oxygen-containing gas supply means in accordance with the required power amount of the external load The control device reduces the supply amount of the oxygen-containing gas to the fuel cell after decreasing the supply amount of the fuel to the fuel cell when the fuel cell is stopped. The oxygen-containing gas supply means and the fuel supply means are respectively controlled.

  In such a fuel cell device, when the fuel cell is stopped, the oxygen-containing gas supply means and the fuel supply means are controlled to reduce the amount of fuel supplied to the fuel cell, and then the oxygen content to the fuel cell is reduced. Control to reduce the amount of gas supply.

  Accordingly, when the fuel cell is stopped, the ratio of the fuel supply amount and the oxygen-containing gas supply amount can be suppressed from being out of a certain range, and the occurrence of incomplete combustion in the fuel cell can be suppressed. Can be reduced.

  The fuel cell device of the present invention is incomplete in the fuel cell because the control device controls the fuel supply means and the oxygen-containing gas supply means according to the increase / decrease in the required power amount of the external load and the start / stop of the fuel cell. Generation of combustion can be suppressed and CO emission can be reduced.

  FIG. 1 shows an example of a fuel cell device that satisfies the structural requirements of the fuel cell device of the present invention, a power generation unit that generates power of the fuel cell, and after heat exchange between the exhaust gas and water of the fuel cell. A hot water storage unit for storing hot water and a circulation pipe for circulating water between these units are constituted. FIG. 1 shows a fuel cell device in which fuel (reformed gas) is obtained by steam reforming as means for obtaining fuel (reformed gas) that can be used in the fuel cell 1.

  The fuel cell device shown in FIG. 1 includes a fuel cell 1 constituting the fuel cell device of the present invention, a fuel supply means 2 for supplying fuel such as natural gas (reformed gas, etc.), and an oxygen-containing gas to the fuel cell 1. Based on the information of the oxygen-containing gas supply means 3 for supply, the power adjustment means 12 for switching the DC power generated by the fuel cell 1 to AC power and supplying it to the external load, the fuel supply based on the information of the power adjustment means 12 A control device 14 for controlling the means 2 and the oxygen-containing gas supply means 3 is provided. Other configurations will be described later.

  In such a fuel cell device, the fuel cell 1 generates power using the fuel supplied from the fuel supply means 2 and the oxygen-containing gas supplied from the oxygen-containing gas supply means 3. The DC power generated by the fuel cell 1 is switched to AC power by a power adjusting means (power conditioner) 12 and supplied to an external load. Here, information on the required power amount of the external load required for the power conditioner 12 is transmitted to the control device 14, and the control device 14 determines the fuel supply amount supplied from the fuel supply means 2 based on the information. The supply amount of the oxygen-containing gas supplied from the oxygen-containing gas supply means 3 is controlled. As a result, the fuel and the oxygen-containing gas are supplied to the fuel cell 1 in accordance with the required power amount of the external load, and the load following operation is performed. In addition, as fuel supply means 2 and oxygen supply means 3, pumps, such as a blower, can be used, for example.

  In this load following operation, fuel is supplied to the fuel cell 1 from the fuel supply means 2 and oxygen-containing gas is supplied from the oxygen-containing gas supply means 3 to the fuel cell 1 in accordance with the required power amount of the external load. The ratio between the fuel amount and the oxygen-containing gas amount (air-fuel ratio) in the fuel cell 1 is temporarily outside a certain range (for example, the air-fuel ratio as a volume ratio is 15 or less, and so on). The air-fuel ratio may be arbitrarily set according to the fuel type, combustion method, equipment used as the fuel supply means, oxygen-containing gas supply means, and the like. In this case, incomplete combustion may occur in the fuel cell 1, and when incomplete combustion occurs, carbon monoxide (CO) may be discharged, or the discharge amount may increase.

  Further, for example, when the fuel cell 1 is a solid oxide fuel cell, it is necessary to maintain the operation temperature at a very high temperature in order to maintain the power generation efficiency. When the oxygen-containing gas is supplied, the temperature of the fuel cell 1 is lowered, and the power generation efficiency of the fuel cell 1 may be reduced.

  Therefore, the fuel cell device according to the present invention supplies the oxygen-containing gas in an amount corresponding to the required power amount of the external load into the fuel cell 1 first when the required power amount of the external load increases, for example. Incomplete combustion in the fuel cell 1 is suppressed.

  Specifically, information on the amount of power supplied from the power conditioner 12 to the external load is transmitted to the control device 14. Here, when information indicating that the amount of power supplied to the external load is increased from the power conditioner 12 is transmitted to the control device 14, the control device 14 supplies the oxygen-containing gas according to the increase amount of required power of the external load. After transmitting a signal for increasing the supply amount of the oxygen-containing gas to the means 3, a signal for increasing the supply amount of the fuel is transmitted to the fuel supply means 2. Thereby, the oxygen-containing gas is supplied to the fuel cell 1 first, and then the fuel is supplied, so that the ratio of the fuel supply amount to the oxygen-containing gas supply amount (air-fuel ratio) in the fuel cell 1 is in a certain range. While being outside, the occurrence of incomplete combustion in the fuel cell 1 can be suppressed, and the amount of CO emissions can be reduced.

  The timing for transmitting a signal for increasing the supply amount to the oxygen-containing gas supply means 3 and the fuel supply means 2 is appropriately set according to the distance from each supply means to the fuel cell 1, the performance of each supply means, and the like. However, at least the oxygen-containing gas is supplied first to the fuel cell 1 (the supply of fuel is started after the supply of the oxygen-containing gas is started, or the supply of fuel is started after the supply of the oxygen-containing gas is started) To be set). In addition, when the supply amount of the oxygen-containing gas and the fuel is confirmed, it can be confirmed by arranging a flow meter or the like until the fuel cell 1 is supplied.

  On the other hand, for example, when the required power amount of the external load decreases, the ratio of the fuel amount to the oxygen-containing gas amount (air-fuel ratio) in the fuel cell 1 is reduced by reducing the fuel supplied to the fuel cell 1 first. The incomplete combustion in the fuel cell 1 is suppressed by preventing the fuel cell 1 from being out of a certain range.

  Specifically, information on the amount of power supplied from the power conditioner 12 to the external load is transmitted to the control device 14. Here, when information indicating that the amount of power supplied from the power conditioner 12 to the external load is reduced is transmitted to the control device 14, the control device 14 determines that the fuel supply means 2 is in accordance with the amount of reduction in the required power of the external load. After transmitting a signal for reducing the supply amount of fuel, a signal for decreasing the supply amount of oxygen-containing gas is transmitted to the oxygen-containing gas supply means 3. As a result, the supply of the fuel gas to the fuel cell 1 is reduced first, and then the supply amount of the oxygen-containing gas is reduced, so that the ratio of the fuel supply amount and the oxygen-containing gas supply amount in the fuel cell 1 is constant. The occurrence of incomplete combustion in the fuel cell 1 can be suppressed and the amount of CO emission can be reduced while suppressing the out of range.

  Thereby, even when the power amount of the external load repeatedly increases and decreases, the oxygen-containing gas supply unit 3 and the fuel supply unit 2 are controlled according to the power amount of the external load, so that the fuel cell 1 is supplied. The ratio of the fuel supply amount and the oxygen-containing gas supply amount can be controlled to be outside a certain range, and the oxygen-containing gas and fuel are supplied according to the amount of electric power of the external load, so that efficient load following operation is performed. Can do.

  When the fuel cell 1 is a solid oxide fuel cell, a more rapid load following operation can be performed.

  By the way, even when the fuel cell 1 is started up, incomplete combustion occurs in the fuel cell 1 because the ratio of the fuel supply amount to the fuel cell 1 and the oxygen-containing gas supply amount is out of a certain range. There is.

  Therefore, in the fuel cell device of the present invention, when the fuel cell 1 is started, the control device 14 transmits a signal for starting the supply of the oxygen-containing gas to the oxygen-containing gas supply unit 3 and then the fuel supply unit. 2 transmits a signal for starting the supply of fuel. Thereby, the oxygen-containing gas is supplied to the fuel cell 1 first, and then the fuel is supplied, so that the ratio of the fuel supply amount and the oxygen-containing gas supply amount in the fuel cell 1 is out of a certain range. While suppressing, generation | occurrence | production of incomplete combustion at the time of starting of the fuel cell 1 can be suppressed, and the discharge | emission amount of CO can be reduced.

  The timing for transmitting the supply start signal to the oxygen-containing gas supply means 3 and the fuel supply means 2 is the same as described above, the distance from each supply means to the fuel cell 1 and the performance of each supply means. It can set suitably by etc.

  On the other hand, when stopping the fuel cell 1, the control device 14 transmits a signal for decreasing the amount of fuel supplied to the fuel cell 1 to the fuel supply unit 2, and then supplies the oxygen-containing gas to the fuel cell 1. Transmit a signal that reduces the amount. Thereby, when the fuel cell 1 is stopped, the ratio of the fuel supply amount and the oxygen-containing gas supply amount is prevented from being out of a certain range, and incomplete combustion occurs when the fuel cell 1 is stopped. The amount of CO emission can be reduced.

  Here, a fuel cell device that satisfies the structural requirements of the present invention will be described using the fuel cell device shown in FIG.

  The fuel supplied from the fuel supply means 2 is steam-reformed with water (including steam) supplied from the water supply means X in the reformer 4 and can be used in the fuel cell 1 (reformed gas). After being reformed, the fuel cell 1 is supplied. When partial oxidation reforming is performed by the reformer 4, partial oxidation reforming can be performed by supplying an oxygen-containing gas from the oxygen-containing gas supply means 3 to the reformer 4.

  Here, the water supply means X is an activated carbon filter device 7 for purifying the water, a reverse osmosis membrane device 8 for further purifying the water purified by the activated carbon filter device 7, and for purifying the purified water to pure water. The ion exchange resin device 9, the water tank 10 for storing pure water, the water pump 11 for supplying water to the reformer, and the reformer 4 are mainly connected to the water supply pipe 5 connected in this order. The water supply pipe 5 is provided with a water supply valve 6 that adjusts the amount of water supplied to the water supply pipe 5.

  As described above, the amount of fuel (reformed gas) supplied from the fuel supply means 2 varies in accordance with the required power amount of the external load and the start / stop of the fuel cell 1. The amount of water (including water vapor) supplied to 4 also needs to be changed in accordance with the amount of fuel supplied from the fuel supply means 2.

  Therefore, the control device 14 transmits a signal for supplying fuel to the fuel supply means 2 in accordance with the required power of the external load, and supplies the water pump 11 to the water pump 11 in accordance with the amount of fuel supplied by the fuel supply means 2. A signal for supplying water to the reformer 4 is transmitted.

  Here, in the supply of fuel from the fuel supply means 2 to the reformer 4 and the supply of water from the water pump 11, when the fuel is supplied to the reformer 4 first, the fuel ( The reforming reaction of the gas to be reformed, etc.) cannot be performed normally, and in the reforming reaction, carbon may be deposited due to the components of the fuel, and this carbon causes deterioration of the fuel cell 1. There is a fear.

  Therefore, when the control device 14 transmits a signal to supply fuel to the fuel supply means 2 in accordance with the required power of the external load, the fuel supply and water supply to the reformer 4 are almost simultaneously performed. Or it is preferable to transmit the signal which supplies water with respect to the water pump 11 from the control apparatus 14 so that water may be supplied previously.

  As a result, the fuel (reformed gas or the like) supplied from the fuel supply means 2 to the reformer 4 is normally steam reformed, and the reformed fuel is supplied to the fuel cell 1, thereby The battery 1 can quickly perform the load following operation and can suppress the deterioration of the fuel cell 1.

  Then, the electric power generated by the load following operation by the fuel cell 1 is converted into AC power by the power conditioner 12 and then quickly supplied to the external load.

  On the other hand, the exhaust gas generated by the power generation of the fuel cell 1 is mainly used to increase or maintain the temperature of the fuel cell 1 and then released to the outside. In order to effectively use the heat of the exhaust gas, The heat can be supplied to the heat exchanger 13 that performs heat exchange between the exhaust gas (exhaust heat) generated by the power generation of the battery 1 and water.

  Here, in FIG. 1, the exhaust gas supplied to the heat exchanger 13 is heat-exchanged with water circulating (circulating) in the heat exchanger 13. The heat-exchanged water (hot water) is circulated through the circulation pipe 17 and stored in the hot water storage tank 18. Further, during heat exchange in the heat exchanger 13, moisture contained in the exhaust gas is generated as condensed water as the temperature of the exhaust gas decreases. Therefore, the condensed water generated by the heat exchange of the exhaust gas is supplied to the water tank 10 through the condensed water supply pipe 19. Thereby, water can be used effectively.

  In addition, since the exhaust gas generated with the power generation of the fuel cell 1 may contain harmful substances such as CO in the exhaust gas, it is preferable to detoxify the CO or the like contained in the exhaust gas with a combustion catalyst or the like. Therefore, for example, it is preferable to provide a combustion catalyst or the like in the vicinity of the exhaust gas exhaust port or between the fuel cell 1 and the heat exchanger 13.

  The CO concentration in the exhaust gas can be measured by providing a CO sensor or the like, and this CO sensor is preferably provided in the vicinity of the exhaust gas outlet of the heat exchanger 13, for example.

  Although the present invention has been described in detail above, the present invention is not limited to the above-described embodiments, and various modifications and improvements can be made without departing from the scope of the present invention.

  For example, when partial oxidation reforming is performed in the reformer 4, an oxygen-containing gas supply unit is provided separately from the oxygen-containing gas supply unit that supplies the oxygen-containing gas to the fuel cell 1. Gas can also be supplied. In this case, the oxygen-containing gas supplied to the fuel cell 1 and the oxygen-containing gas supplied to the reformer 4 can be controlled separately.

It is a block diagram which shows an example of the fuel cell apparatus which comprises the structure of this invention.

Explanation of symbols

1: Fuel cell 2: Fuel supply means 3: Oxygen-containing gas supply means 4: Reformer 12: Power conditioner

Claims (4)

Fuel cell, fuel supply means for adjusting the amount of fuel supplied to the fuel cell, oxygen-containing gas supply means for adjusting the amount of oxygen-containing gas supplied to the fuel cell, and the fuel cell Power adjustment means for supplying the electric power generated by the power generation to an external load, and a control device for controlling the fuel supply means and the oxygen-containing gas supply means according to the required power amount of the external load, When the required power amount of the external load is increased, the control device increases the supply amount of the oxygen-containing gas supplied to the fuel cell, and then increases the supply amount of fuel to the fuel cell. An oxygen-containing gas supply means and the fuel supply means are controlled respectively. Fuel cell, fuel supply means for adjusting the amount of fuel supplied to the fuel cell, oxygen-containing gas supply means for adjusting the amount of oxygen-containing gas supplied to the fuel cell, and the fuel cell Power adjustment means for supplying the electric power generated by the power generation to an external load, and a control device for controlling the fuel supply means and the oxygen-containing gas supply means according to the required power amount of the external load, When the required power amount of the external load is reduced, the control device reduces the supply amount of fuel supplied to the fuel cell and then decreases the supply amount of oxygen-containing gas to the fuel cell. An oxygen-containing gas supply means and the fuel supply means are controlled respectively. Fuel cell, fuel supply means for adjusting the amount of fuel supplied to the fuel cell, oxygen-containing gas supply means for adjusting the amount of oxygen-containing gas supplied to the fuel cell, and the fuel cell Power adjustment means for supplying the electric power generated by the power generation to an external load, and a control device for controlling the fuel supply means and the oxygen-containing gas supply means according to the required power amount of the external load, The control device includes the oxygen-containing gas supply unit and the oxygen-containing gas supply unit so as to start supply of fuel to the fuel cell after starting supply of the oxygen-containing gas to the fuel cell when the fuel cell is started. A fuel cell device that controls each of the fuel supply means. Fuel cell, fuel supply means for adjusting the amount of fuel supplied to the fuel cell, oxygen-containing gas supply means for adjusting the amount of oxygen-containing gas supplied to the fuel cell, and the fuel cell Power adjustment means for supplying the electric power generated by the power generation to an external load, and a control device for controlling the fuel supply means and the oxygen-containing gas supply means according to the required power amount of the external load, The control device reduces the supply amount of fuel to the fuel cell and then decreases the supply amount of oxygen-containing gas to the fuel cell when the fuel cell is stopped. A fuel cell device that controls a supply means and the fuel supply means, respectively.

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