JP2006100153A - Operation method of solid oxide fuel cell, and power generation facility of solid oxide fuel cell - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an operating method of a solid oxide fuel cell in which power generation can be resumed rapidly even if operation has been stopped in a high temperature state, and provide a power generating facility of the solid oxide fuel cell using this method. <P>SOLUTION: In this method, a stopping process of power generation operation is carried out in which, after feeding of a fuel gas 1 and air 2 is stopped in the high temperature state by purging the interior of the solid oxide fuel cell 22 with nitrogen gas 3, the power generation operation is stopped in the high temperature state, and a resuming process of power generation operation to resume the power generation operation is carried out in which, after the nitrogen gas 3 is supplied and circulated to fuel electrode sides and oxidation electrode sides of respective cells of the solid oxide fuel cell 22 during stopping of the power generation operation in the high temperature state, the fuel gas 1 is fed and circulated to the fuel electrode sides of respective cells of the solid oxide type fuel cell 22 while gradually increasing it and the air 2 is fed to air electrode sides of respective cells of the solid oxide type fuel cell 22 while gradually increasing it. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an operation method for restarting a solid oxide fuel cell while maintaining a high temperature state, and a solid oxide fuel cell power generation facility using the method.

  In a solid oxide fuel cell, a cell is formed by sandwiching an electrolyte made of a solid oxide between an air electrode made of a metal oxide and a fuel electrode made of a metal, and a plurality of such cells and conductive separators are alternately arranged. Air that is an oxidizing gas containing oxygen via an air supply manifold on the air electrode side of each cell of the stack while stacking to form a stack and maintaining the stack at a high temperature (about 700 to 1000 ° C.) In addition, a fuel gas containing hydrogen or carbon monoxide is supplied to the fuel electrode side of each cell of the stack via a fuel supply manifold, and oxygen and hydrogen or carbon monoxide are electrochemically reacted in each cell. It is possible to obtain electric power by reacting automatically, and it is considered promising as a distributed power source in homes or a business power source of an electric power company.

  In such a solid oxide fuel cell, when the fuel gas leaks to the air electrode side or the air leaks to the fuel electrode side at a high temperature state, the air electrode made of metal oxide is reduced, There is a possibility that the fuel electrode made of metal is oxidized and power generation performance is deteriorated, and there is a possibility that air and fuel gas cause a combustion reaction and damage the stack. For this reason, in a conventional solid oxide fuel cell, various kinds of sealing materials are applied between the air electrode side and the fuel electrode side to prevent leakage of these gases (for example, the following patents) Reference 1 etc.).

JP 2004-146131 A

  However, it is difficult to completely prevent air and fuel gas leakage even in the case of a solid oxide fuel cell to which a sealing material as described above is applied. Is temporarily stopped (the supply of air and fuel gas is temporarily interrupted in a high temperature state) and then the power generation is resumed (the supply of air and fuel gas is started in a high temperature state), that is, air and fuel in a high temperature state. When feeding gas, the flow and flow rate of air and fuel gas immediately after the start of feeding are unstable, and these gases do not contribute to power generation and are likely to leak and are in a high temperature state. It becomes easy.

  Therefore, in the case described above, after the stack is cooled to a low temperature (about 300 ° C.), air and fuel gas supply is started, and the flow rate and flow rate of these gases are stabilized. By heating the stack again to the operating temperature (700 to 1000 ° C.), the occurrence of the above-described problems is prevented. For this reason, in resuming operation, not only a lot of energy is wasted, but it takes a lot of time to lower and raise the temperature of the stack, and power generation cannot be resumed quickly, It has weaknesses in practicality as a distributed power source in homes and business power sources of electric power companies.

  Therefore, the present invention provides a method for operating a solid oxide fuel cell capable of quickly restarting power generation even when operation is stopped in a high temperature state, and a solid oxide fuel cell power generation using this method. The purpose is to provide equipment.

  In order to solve the above-described problem, the solid oxide fuel cell operating method according to the first invention includes hydrogen or carbon monoxide on the fuel electrode side of each cell of the stack of the solid oxide fuel cell. The fuel gas is fed, the oxidizing gas containing oxygen is fed to the air electrode side of each cell of the stack of the solid oxide fuel cell, and the fuel gas and the oxidizing gas are fed into the solid oxide of each cell. An operation method of a solid oxide fuel cell that obtains electric power by electrochemically reacting in a high temperature state in an electrolyte composed of a substance, and after stopping the supply of the fuel gas and the oxidizing gas in a high temperature state, A power generation operation stopping step of stopping the power generation operation at a high temperature by purging the inside of the solid oxide fuel cell with an inert gas, and each cell of the solid oxide fuel cell being stopped at a high temperature Of the fuel And supplying the inert gas to the air electrode side and the air electrode side, and then supplying and distributing the fuel gas to the fuel electrode side of each cell of the solid oxide fuel cell, Performing a power generation operation restarting step of restarting the power generation operation in a state where the high temperature state of the cell is maintained by supplying and circulating the oxidizing gas to the air electrode side of each cell of the solid oxide fuel cell It is characterized by.

  The operation method of the solid oxide fuel cell according to the second invention is the operation method of the solid oxide fuel cell according to the first invention, wherein the power generation operation resuming step is stopped at a high temperature state in the power generation operation. An inert gas feeding step for feeding and circulating the inert gas to the fuel electrode side and the air electrode side, and after feeding and circulating the inert gas, the inert gas and the A mixed gas for fuel mixed with a fuel gas is fed to the fuel electrode side of each cell of the solid oxide fuel cell and circulated, and the mixed gas for oxidation is mixed with the inert gas and the oxidizing gas. A mixed gas feeding step of feeding and circulating gas to the air electrode side of each cell of the solid oxide fuel cell; and after feeding and circulating the mixed gas, respectively, only the fuel gas The fuel electrode side of each cell of the solid oxide fuel cell With circulating by feed, characterized in that only the oxidizing gas performs a power generation gas delivery step be distributed to feed to the air electrode side of each cell of the solid oxide fuel cell.

  According to a third aspect of the present invention, there is provided the solid oxide fuel cell operating method according to the second aspect of the invention, wherein the mixed gas feeding step gradually determines the ratio of the fuel gas in the fuel mixed gas to be fed. And the ratio of the oxidizing gas in the oxidizing gas mixture to be fed is gradually increased.

  According to a fourth aspect of the present invention, there is provided a method for operating a solid oxide fuel cell according to the third aspect, wherein the mixed gas feeding step includes the fuel gas and the oxidizing gas in the solid oxide fuel cell. The fuel gas in the fuel mixed gas is gradually increased at a rate that does not cause an abnormal reaction due to leakage of the fuel, and the oxidizing gas in the oxidizing gas mixture is gradually increased. To do.

  In order to solve the above-described problem, a solid oxide fuel cell power generation facility according to a fifth invention includes a solid oxide fuel cell and a fuel for each cell of the stack of the solid oxide fuel cell. A fuel gas feeding means for feeding a fuel gas containing hydrogen or carbon monoxide to the pole side; and an oxidizing gas containing oxygen to the air electrode side of each cell of the stack of the solid oxide fuel cell. Oxidizing gas feeding means for feeding, fuel-side inert gas feeding means for feeding an inert gas to the fuel electrode side of each cell of the stack of the solid oxide fuel cell, and the solid oxide fuel cell The oxidizing side inert gas feeding means for feeding an inert gas to the air electrode side of each cell of the stack, and the feeding of the fuel gas and the oxidizing gas to the solid oxide fuel cell in a high temperature state The fuel gas supply means and the front to stop at After controlling the oxidizing gas feeding means, the fuel side inert gas feeding means and the oxidizing side inert gas feeding means are controlled so as to purge the inside of the solid oxide fuel cell with an inert gas. The power generation operation is stopped at a high temperature state, and the inert gas is supplied to the fuel electrode side and the air electrode side of each cell of the solid oxide fuel cell being stopped at a high temperature state. After controlling the fuel-side inert gas feeding means and the oxidation-side inert gas feeding means so as to circulate, the fuel gas is fed to the fuel electrode side of each cell of the solid oxide fuel cell. The fuel gas supply means is controlled so as to be circulated, and the oxidant gas is supplied so as to be circulated to the air electrode side of each cell of the solid oxide fuel cell. By controlling the power supply means Characterized in that a control means for resuming the transfer.

  The solid oxide fuel cell power generation facility according to a sixth aspect of the present invention is the solid oxide fuel cell power generation facility according to the fifth aspect of the present invention, wherein the control means has the fuel of each cell of the solid oxide fuel cell being stopped in a power generation operation at a high temperature. The fuel-side inert gas feeding means and the oxidation-side inert gas feeding means are controlled so that the inert gas is fed and circulated to the electrode side and the air electrode side, and then the inert gas The fuel-side inert gas feeding means and the fuel gas so as to feed and circulate a mixed gas for fuel, which is a mixture of fuel and the fuel gas, to the fuel electrode side of each cell of the solid oxide fuel cell Controlling the feeding means, and feeding and circulating the mixed gas for oxidation, which is a mixture of the inert gas and the oxidizing gas, to the air electrode side of each cell of the solid oxide fuel cell Oxidizing side inert gas feeding means and said oxidized gas After controlling the feeding means, the fuel-side inert gas feeding means and the fuel gas are fed so that only the fuel gas is fed to the fuel electrode side of each cell of the solid oxide fuel cell. The oxidizing side inert gas feeding means and the oxidizing gas so as to control the feeding means and feed only the oxidizing gas to the air electrode side of each cell of the solid oxide fuel cell. It is characterized by controlling the feeding means.

  In a solid oxide fuel cell power generation facility according to a seventh invention, in the sixth invention, the control means gradually increases the ratio of the fuel gas in the fuel mixed gas to be fed. And controlling the fuel-side inert gas feeding means and the fuel gas feeding means, and gradually increasing the ratio of the oxidizing gas in the oxidizing gas mixture to be fed. It controls the feeding means and the oxidizing gas feeding means.

  According to an eighth aspect of the present invention, there is provided a solid oxide fuel cell power generation facility according to the seventh aspect of the present invention, wherein the abnormality detects an abnormal reaction due to leakage of the fuel gas and the oxidizing gas in the solid oxide fuel cell. The fuel gas in the mixed gas for fuel is provided at a rate that does not cause an abnormal reaction due to leakage of the fuel gas and the oxidizing gas in the solid oxide fuel cell. The fuel-side inert gas supply means and the fuel gas supply means are controlled based on a signal from the abnormal reaction detection means so as to gradually increase the oxidant gas in the oxidation mixed gas. The oxidation side inert gas supply means and the oxidation gas supply means are controlled based on a signal from the abnormal reaction detection means so as to gradually increase. That.

  A solid oxide fuel cell power generation facility according to a ninth invention is the eighth invention, wherein the abnormal reaction detection means measures voltage inside the solid oxide fuel cell; and An internal temperature measuring means for measuring the temperature inside the solid oxide fuel cell; an exhaust fuel gas temperature measuring means for measuring the temperature of the used fuel gas discharged from the solid oxide fuel cell; Exhaust oxidizing gas temperature measuring means for measuring the temperature of the used oxidizing gas discharged from the solid oxide fuel cell, and the pressure of the used fuel gas discharged from the solid oxide fuel cell. At least one of an exhaust fuel gas pressure measuring means for measuring and an exhaust oxidizing gas pressure measuring means for measuring the pressure of the used oxidizing gas discharged from the solid oxide fuel cell; And wherein the Rukoto.

  According to a tenth aspect of the present invention, there is provided the solid oxide fuel cell power generation facility according to any one of the fifth to ninth aspects, wherein the flow of the spent fuel gas discharged from the solid oxide fuel cell is At least the fuel-side opening / closing valve among a fuel-side opening / closing valve disposed in the passage and an oxidation-side opening / closing valve disposed in the flow path of the used oxidizing gas discharged from the solid oxide fuel cell It is provided with a valve.

  According to the solid oxide fuel cell operation method and the solid oxide fuel cell power generation facility using this method according to the present invention, the temperature of the solid oxide fuel cell stack is lowered even when the operation is stopped in a high temperature state. Power generation can be resumed quickly without making it possible to drastically reduce waste of thermal energy and greatly improve operation responsiveness. Practicality as a power source can be greatly enhanced.

  An embodiment of a solid oxide fuel cell operation method according to the present invention and a solid oxide fuel cell power generation facility using this method will be described with reference to FIGS. FIG. 1 is a schematic configuration diagram of a solid oxide fuel cell power generation facility, FIG. 2 is a flowchart when the operation method of the solid oxide fuel cell is stopped, and FIG. 3 is an operation method of the solid oxide fuel cell. It is a flowchart in the case of a driving | operation restart.

  As shown in FIG. 1, a fuel gas supply source 11 for supplying a fuel gas 1 containing hydrogen or carbon monoxide communicates with an inlet of a feed fan 13 via a flow rate adjusting valve 11a and a flow rate detector 11b. ing. The delivery port of the feed fan 13 communicates with one receiving port of the heat exchanger 21. A nitrogen gas cylinder 12 for supplying nitrogen gas 3 which is an inert gas is provided between the outlet of the supply fan 13 and one of the inlets of the heat exchanger 21 via a flow rate adjusting valve 12a and a flow rate detector 12b. Contact.

  One outlet of the heat exchanger 21 communicates with the fuel supply manifold of the solid oxide fuel cell 22. The fuel discharge manifold of the solid oxide fuel cell 22 is received by the combustor 23 via a temperature sensor 17a that is an exhaust fuel gas temperature measurement means, a pressure sensor 18a that is an exhaust fuel gas pressure measurement means, and a fuel side on-off valve 19a. In addition to communicating with the inlet, it also communicates with the inlet of the feeding fan 13.

  The exhaust port of the combustor 23 communicates with one receiving port of the heat exchanger 24. One outlet of the heat exchanger 24 communicates with an exhaust gas inlet of an exhaust gas boiler 25 that is an exhaust heat reuse means. The exhaust gas outlet of the exhaust gas boiler 25 communicates with the chimney 26.

  The air filter 14 communicates with the inlet of the feed fan 16 via the flow rate adjusting valve 14a and the flow rate detector 14b. The outlet of the supply fan 16 communicates with the other inlet of the heat exchanger 24. A nitrogen gas cylinder 15 for feeding nitrogen gas 3 communicates between the delivery port of the feed fan 16 and the other receiving port of the heat exchanger 24 via a flow rate adjusting valve 15a and a flow rate detector 15b. Yes.

  The other outlet of the heat exchanger 24 communicates with the other receiving port of the heat exchanger 21. The other outlet of the heat exchanger 21 communicates with the air supply manifold of the fuel cell 22. The air discharge manifold of the fuel cell 22 is connected to the receiving port of the combustor 23 via a temperature sensor 17b as exhaust oxidant gas temperature measuring means, a pressure sensor 18b as exhaust oxidant gas pressure measuring means, and an oxidation side on-off valve 19b. I'm in touch.

  The fuel gas supply source 11, the cylinders 12, 15, the flow rate detectors 11 b, 12 b, 14 b, 15 b of the air filter 14, the temperature sensors 17 a, 17 b near the exhaust manifold of the fuel cell 22, and the pressure The sensors 18a and 18b are electrically connected to the input unit of the control device 20 which is a control means. The output unit of the control device 20 is electrically connected to the cylinders 11, 12, 15 and the flow rate adjusting valves 11 a, 12 a, 14 a, 15 a of the air filter 14 and the feed fans 13, 16, and the combustion It is electrically connected to the on-off valves 19a and 19b disposed near the receiving port of the vessel 23.

  Further, a temperature detector (not shown), which is an internal temperature measuring means for measuring the internal temperature of the fuel cell 22, and a voltage measuring means for measuring the internal voltage of the fuel cell 22 are input to the control device 20. The control device 20 includes the flow rate detectors 11b, 12b, 14b, and 15b, the temperature sensors 17a and 17b, the pressure sensors 18a and 18b, Based on the signals from the temperature detector and the voltmeter, the flow rate adjusting valves 11a, 12a, 14a, 15a, the feed fans 13, 16, and the on-off valves 19a, 19b can be adjusted. (Details will be described later).

  In this embodiment, the fuel gas supply unit 11, the flow rate adjustment valve 11 a, the flow rate detector 11 b, the supply fan 13, etc. constitute a fuel gas supply means, and the air filter 14, the flow rate adjustment valve 14 a, the flow rate detection The oxidizing gas feeding means is constituted by the vessel 14b, the feeding fan 16 and the like, and the fuel side inert gas feeding means is constituted by the nitrogen gas cylinder 12, the flow rate adjusting valve 12a, the flow rate detector 12b and the like, and the nitrogen gas cylinder 15 and the flow rate are set. The regulating valve 15a, the flow rate detector 15b, etc. constitute the oxidizing side inert gas feeding means, the heat exchanger 21, the combustor 23, etc. constitute the fuel gas heating means, and the combustor 23, the heat exchanger 24, etc. Oxidizing gas heating means is constituted, and abnormal reaction detecting means is constituted by the temperature sensors 17a and 17b, the pressure sensors 18a and 18b, the temperature detector, the voltmeter and the like. The present invention provides such is not limited to various members described above was applied in the present embodiment, we are also possible to apply various other members or the like having a similar functionality.

  Next, the operation of the solid oxide fuel cell power generation facility 10 according to this embodiment, that is, the operation method of the solid oxide fuel cell 22 will be described.

  The control device 20 is operated to operate the feed fans 13 and 16, and the fuel gas 1 and the oxidizing gas are adjusted while adjusting the flow rate adjusting valves 11a and 14a based on signals from the flow rate detectors 11b and 14b. While supplying the air 2 at a predetermined flow rate and heating the fuel gas 1 through the heat exchanger 21 (about 900 to 1000 ° C.), the fuel electrode of each cell in the stack from the fuel supply manifold of the fuel cell 22. The air 2 is heated through the heat exchanger 24 (about 900 to 1000 ° C.) while being fed from the air supply manifold of the fuel cell 22 to the air electrode side of each cell in the stack. Then, the fuel gas 1 and the air 2 react electrochemically to generate electric power.

  Since the spent fuel gas 1 used for the reaction contains unreacted hydrogen, carbon monoxide, or the like, a part thereof is sent again to one of the inlets of the heat exchanger 21 to newly The remaining fuel gas 1 is again used for power generation, while the remainder is fed into the combustor 23 together with the used air 2 subjected to the reaction and burned to become detoxified exhaust gas 4 and heat. After being supplied to the exchanger 24 and used as a heat source for heating the air 2 and the fuel gas 1 supplied to the fuel cell 22, it is supplied to the exhaust gas boiler 25 and further used as a heat source for the boiler. Then, it is discharged to the outside through the chimney 26.

  When the power generation operation is performed in this manner, when the power generation is temporarily stopped in accordance with the load fluctuation, the control device 20 sends the fuel gas 1 and the air 2 as shown in FIG. After adjusting the flow rate adjusting valves 11a and 14a to stop supply and stopping the operation of the supply fans 13 and 16 to stop power generation (S11), the nitrogen gas 3 is sent into the fuel cell 22. Nitrogen gas 3 is supplied from the nitrogen gas cylinders 12 and 15 at a predetermined flow rate while adjusting the flow rate adjusting valves 12a and 15a based on signals from the flow rate detectors 12b and 15b so that the fuel cell 22 is supplied. When the fuel electrode side and the air electrode side of each cell in the stack are purged with nitrogen gas 3 (S12), the on-off valves 19a and 19b are closed, and the air 2 remaining in the combustor 23 is stacked in the fuel cell 22 stack. Inside The fuel gas 1 remaining in the combustor 23 is prevented from flowing backward into the air electrode side of each cell in the stack of the fuel cell 22 while preventing the reverse flow into the fuel electrode side of each cell (S13). ). At this time, the fuel cell 22 maintains a high temperature state without lowering the temperature (the power generation operation stopping step).

  Subsequently, when the power generation is resumed in accordance with the load fluctuation, as shown in FIG. 3, the control device 20 opens the on-off valves 19a and 19b (S21), and the nitrogen gas 3 is supplied to the fuel cell. The nitrogen gas 3 is fed at a predetermined flow rate from the nitrogen gas cylinders 12 and 15 while adjusting the flow rate regulating valves 12a and 15a based on the signals from the flow rate detectors 12b and 15b so as to be fed again into the inside. When the flow is started (S22: inert gas feeding step), the feed fans 13 and 16 are operated so that the fuel gas 1 and air 2 are gradually fed into the fuel cell 22 to detect the flow rate. The flow rates of the fuel gas 1 and the air 2 are gradually increased while adjusting the flow rate adjusting valves 11a and 14a based on the signals from the devices 11b and 14b, and the flow rates of the fuel gas 1 and the air 2 are increased. The flow rate adjusting valves 12a and 15a are adjusted based on signals from the flow rate detectors 12b and 15b so as to gradually reduce the amount of nitrogen gas 3 fed into the fuel cell 22, that is, the fuel gas A fuel mixed gas in which the fuel gas 1 and the nitrogen gas 3 are mixed so as to gradually increase the ratio of 1 is sent to the fuel electrode side of each cell in the stack of the fuel cell 22 and distributed. An oxidizing gas mixture in which the air 2 and the nitrogen gas 3 are mixed so as to gradually increase the ratio of the air 2 is sent to the air electrode side of each cell in the stack of the fuel cell 22 and circulated (S23). : Mixed gas feeding process).

  At this time, the control device 20 increases the supply amount of the fuel gas 1 and the air 2 and reduces the supply amount of the nitrogen gas 3 at a rate that does not cause an abnormal reaction due to leakage in the fuel cell 22. The temperature sensors 17a and 17b (exhaust gas temperature from the fuel cell 22 rises when an abnormal reaction due to leak occurs), the pressure sensors 18a and 18b (exhaust gas pressure from the fuel cell 22 when leak occurs) ), The temperature detector (the temperature in the fuel cell 22 rises when an abnormal reaction due to leakage occurs), the voltmeter (the voltage of the fuel cell 22 when the abnormal reaction due to leakage occurs) The flow rate adjusting valves 11a, 12a, 14a and 15a are controlled based on a signal from

  When the supply of the nitrogen gas 3 is stopped and only the fuel gas 1 and the air 2 are supplied, that is, when the fuel gas 1 and the air 2 are constantly supplied (S24: gas generation process for power generation). Then, power generation is started again (S25) (the power generation operation resuming step).

  That is, when gas is circulated in the fuel cell 22, since the gas flow rate and flow rate are unstable at the beginning of distribution, the fuel gas 1 and air 2 are all fed into the fuel cell 22 from the beginning. In this embodiment, the fuel gas 1 and the air 2 leak without being able to contribute to power generation and easily cause an abnormal reaction. Therefore, in this embodiment, the nitrogen gas 3 is first circulated in the fuel cell 22, After stabilizing the flow rate and flow velocity of the gas flowing through the fuel cell 22, the fuel gas 1 and air 2 are fed into the fuel cell 22.

  For this reason, in the present embodiment, the fuel gas 1 and air 2 do not flow through the fuel cell 22 at the beginning of the flow when the gas flow rate and flow rate become unstable, and the fuel flow is stabilized after the gas flow rate and flow rate are stabilized. Since the gas 1 and the air 2 circulate in the fuel cell 22, it is possible to prevent the occurrence of an abnormal reaction due to leakage even in a high temperature state.

  Therefore, according to this embodiment, even if the stack of the fuel cell 22 is stopped in a high temperature state, power generation can be resumed quickly without lowering the temperature, so that waste of heat energy can be greatly reduced. In addition, the driving responsiveness can be greatly enhanced, and the utility as a distributed power source at home or a business power source of a power company can be greatly enhanced.

  In the present embodiment, all of the temperature sensors 17a and 17b, the pressure sensors 18a and 18b, the temperature detector, and the voltmeter are applied as the abnormal reaction detection means. However, depending on various conditions, the temperature sensor It is also possible to apply at least one of 17a and 17b, pressure sensors 18a and 18b, the temperature detector, and the voltmeter.

  In this embodiment, both the fuel side on / off valve 19a and the oxidation side on / off valve 19b are applied. However, the oxidation side on / off valve 19b may be omitted and only the fuel side on / off valve 19a may be used. .

  Further, the increasing tendency of the fuel gas 1 and air 2 (the decreasing tendency of the nitrogen gas 3) in the mixed gas feeding process (S23) is gradually (gradient) or stepped (step) depending on various conditions. May be selected as appropriate.

  Further, in this embodiment, as shown in FIG. 1, the nitrogen gas cylinders 12 and 15 are connected to the outlet side of the supply fans 13 and 16, but the supply pressure of the nitrogen gas cylinders 12 and 15 is low. In such a case, for example, as shown in FIG. 4, the nitrogen gas cylinders 12 and 15 may be connected to the receiving side of the feeding fans 13 and 16.

  The solid oxide fuel cell operation method and the solid oxide fuel cell power generation facility according to the present invention have very high practicality as a distributed power source at home or business power source of an electric power company, etc. It can be used extremely beneficially.

1 is a schematic configuration diagram of an embodiment of a solid oxide fuel cell power generation facility according to the present invention. It is a flowchart in the case of the operation stop of the operating method of the solid oxide fuel cell which concerns on this invention. It is a flowchart in the case of the restarting of the operation method of the solid oxide fuel cell which concerns on this invention. It is a schematic block diagram of other embodiment of the solid oxide fuel cell power generation equipment which concerns on this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Fuel gas 2 Air 3 Nitrogen gas 4 Exhaust gas 10 Solid oxide fuel cell power generation equipment 11 Fuel gas cylinder 11a Flow control valve 11b Flow rate detector 12 Nitrogen gas cylinder 12a Flow rate adjustment valve 12b Flow rate detector 13 Feed fan 14 Air filter 14a Flow rate Adjustment valve 14b Flow rate detector 15 Nitrogen gas cylinder 15a Flow rate adjustment valve 15b Flow rate detector 16 Supply fan 17a, 17b Temperature sensor 18a, 18b Pressure sensor 19a Fuel side on / off valve 19b Oxidation side on / off valve 20 Controller 21 Heat exchanger 22 Solid Oxide fuel cell 23 Combustor 24 Heat exchanger 25 Exhaust gas boiler 26 Chimney

Claims (10)

A fuel gas containing hydrogen or carbon monoxide is supplied to the fuel electrode side of each cell of the stack of the solid oxide fuel cell, and oxygen is supplied to the air electrode side of each cell of the stack of the solid oxide fuel cell. Operation of a solid oxide fuel cell that supplies electric power by supplying an oxidizing gas contained therein and electrochemically reacting the fuel gas and the oxidizing gas in a high-temperature state in an electrolyte composed of a solid oxide in each cell A method,
After stopping the supply of the fuel gas and the oxidizing gas in a high temperature state, the power generation operation stopping step of stopping the power generation operation in a high temperature state by purging the inside of the solid oxide fuel cell with an inert gas;
After the inert gas is supplied and circulated to the fuel electrode side and the air electrode side of each cell of the solid oxide fuel cell that is stopped in power generation at a high temperature, the solid oxide fuel cell By supplying and distributing the fuel gas to the fuel electrode side of each cell, and supplying and distributing the oxidizing gas to the air electrode side of each cell of the solid oxide fuel cell, A method of operating a solid oxide fuel cell, comprising: performing a power generation operation resuming step of resuming power generation operation while maintaining a high temperature state of the cell. In claim 1,
The power generation operation resuming step includes
An inert gas feeding step for feeding and circulating the inert gas to the fuel electrode side and the air electrode side of each cell of the solid oxide fuel cell that is stopped in a power generation operation at a high temperature;
After supplying and distributing the inert gas, a mixed gas for fuel obtained by mixing the inert gas and the fuel gas is supplied to the fuel electrode side of each cell of the solid oxide fuel cell. And a mixed gas feeding step for feeding and circulating the mixed gas for oxidation, which is a mixture of the inert gas and the oxidizing gas, to the air electrode side of each cell of the solid oxide fuel cell; ,
After each of the mixed gases is fed and circulated, only the fuel gas is fed to the fuel electrode side of each cell of the solid oxide fuel cell and circulated, and only the oxidizing gas is circulated. A method of operating a solid oxide fuel cell, comprising: a power generation gas supply step of supplying and distributing the gas to the air electrode side of each cell of the oxide fuel cell. In claim 2,
The mixed gas feeding step includes
The ratio of the fuel gas in the fuel gas mixture to be fed is gradually increased, and the ratio of the oxidizing gas in the fuel gas mixture to be fed is gradually increased. Operation method of solid oxide fuel cell. In claim 3,
The mixed gas feeding step includes
The fuel gas in the fuel mixed gas is gradually increased at a rate that does not cause an abnormal reaction due to leakage of the fuel gas and the oxidizing gas in the solid oxide fuel cell, and the oxidizing gas mixture A method of operating a solid oxide fuel cell, characterized by gradually increasing the oxidizing gas therein. A solid oxide fuel cell;
Fuel gas supply means for supplying a fuel gas containing hydrogen or carbon monoxide to the fuel electrode side of each cell of the stack of the solid oxide fuel cell;
An oxidizing gas supply means for supplying an oxidizing gas containing oxygen to the air electrode side of each cell of the stack of the solid oxide fuel cell;
Fuel-side inert gas feeding means for feeding an inert gas to the fuel electrode side of each cell of the stack of the solid oxide fuel cell;
Oxidation side inert gas feeding means for feeding inert gas to the air electrode side of each cell of the stack of the solid oxide fuel cell;
After controlling the fuel gas feeding means and the oxidizing gas feeding means to stop the feeding of the fuel gas and the oxidizing gas to the solid oxide fuel cell in a high temperature state, the solid oxide form By controlling the fuel-side inert gas feeding means and the oxidation-side inert gas feeding means so as to purge the inside of the fuel cell with an inert gas, the power generation operation is stopped at a high temperature state and at a high temperature state. The fuel-side inert gas feeding means and the fuel-side inert gas feeding means so as to feed and circulate the inert gas to the fuel electrode side and the air electrode side of each cell of the solid oxide fuel cell that is in the power generation stoppage After controlling the oxidizing side inert gas feeding means, the fuel gas feeding means is controlled so as to feed and circulate the fuel gas to the fuel electrode side of each cell of the solid oxide fuel cell. And the solid oxide form Control means for restarting the power generation operation by controlling the oxidizing gas supply means so as to supply and circulate the oxidizing gas to the air electrode side of each cell of the rechargeable battery. Solid oxide fuel cell power generation facility. In claim 5,
The control means is
The fuel-side inert gas supply so that the inert gas is supplied to and distributed through the fuel electrode side and the air electrode side of each cell of the solid oxide fuel cell that is suspended in power generation at a high temperature. And controlling the oxidizing side inert gas feeding means,
The fuel-side inert gas feeding means so that a fuel mixed gas obtained by mixing the inert gas and the fuel gas is fed to the fuel electrode side of each cell of the solid oxide fuel cell and circulated. And controlling the fuel gas supply means, and supplying an oxidative mixed gas obtained by mixing the inert gas and the oxidizing gas to the air electrode side of each cell of the solid oxide fuel cell for distribution After controlling the oxidizing side inert gas feeding means and the oxidizing gas feeding means,
Controlling the fuel-side inert gas feeding means and the fuel gas feeding means so that only the fuel gas is fed to the fuel electrode side of each cell of the solid oxide fuel cell and circulated; The oxidizing side inert gas feeding means and the oxidizing gas feeding means are controlled so that only the oxidizing gas is sent and circulated to the air electrode side of each cell of the solid oxide fuel cell. There is a solid oxide fuel cell power generation facility. In claim 6,
The control means is
The fuel-side inert gas feeding means and the fuel gas feeding means are controlled so as to gradually increase the ratio of the fuel gas in the fuel mixed gas to be fed, and the oxidizing mixture to be fed A solid oxide fuel cell power generation facility characterized by controlling the oxidizing side inert gas feeding means and the oxidizing gas feeding means so as to gradually increase the ratio of the oxidizing gas in the gas . In claim 7,
An abnormal reaction detecting means for detecting an abnormal reaction due to leakage of the fuel gas and the oxidizing gas in the solid oxide fuel cell;
The control means is
The abnormal reaction detecting means so as to gradually increase the fuel gas in the fuel mixed gas at a rate not causing an abnormal reaction due to leakage of the fuel gas and the oxidizing gas in the solid oxide fuel cell. And controlling the fuel-side inert gas feeding means and the fuel gas feeding means based on the signal from the abnormal reaction detection means so as to gradually increase the oxidizing gas in the oxidizing gas mixture. The solid oxide fuel cell power generation facility is characterized in that the oxidation side inert gas supply means and the oxidation gas supply means are controlled on the basis of the above signal. In claim 8,
The abnormal reaction detection means,
Voltage measuring means for measuring the internal voltage of the solid oxide fuel cell;
An internal temperature measuring means for measuring an internal temperature of the solid oxide fuel cell;
Exhaust fuel gas temperature measuring means for measuring the temperature of the spent fuel gas discharged from the solid oxide fuel cell;
Exhaust oxidant gas temperature measuring means for measuring the temperature of the used oxidant gas discharged from the solid oxide fuel cell;
Exhaust fuel gas pressure measuring means for measuring the pressure of the spent fuel gas discharged from the solid oxide fuel cell;
A solid oxide fuel cell power generation facility, characterized in that it is at least one of exhausted oxidant gas pressure measuring means for measuring the pressure of the used oxidizing gas discharged from the solid oxide fuel cell. . In any one of Claims 5-9,
A fuel-side on-off valve disposed in a flow path of the spent fuel gas discharged from the solid oxide fuel cell;
Solid oxidation characterized by comprising at least the fuel side on / off valve of an oxidation side on / off valve disposed in a flow path of the used oxidizing gas discharged from the solid oxide fuel cell. Physical fuel cell power generation facility.

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