JP5344565B2 - Power generator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a solid oxide fuel cell power generation device achieving high efficiency and high output at low cost, a solid oxide fuel cell power generation device capable of using liquid fuel and suppressing deposition of carbon due to carbonization of fuel gas in an electrode or the like of a power generation body, and a solid oxide fuel cell power generation device capable of using the deposited carbon as fuel and generating power again by using the liquid fuel after the deposited carbon has been consumed. <P>SOLUTION: In the power generation device, a power generation part 54 is disposed at the center part of a heating furnace 11, and an injector 55 spraying liquid fuel into a second reaction chamber 22 is connected to the bottom of the second reaction chamber 22 to spray the liquid fuel toward a power generation body 10. The reaction chamber 22 is tightly closed and temperature in the reaction chamber is controlled. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a power generation apparatus that generates power using, for example, a power generation body of a solid oxide fuel cell (SOFC).

  Conventionally, there has been known a solid oxide fuel cell (hereinafter referred to as SOFC) in which a ceramic solid electrolyte is used as an electrolyte of a fuel cell and a cell is formed by sandwiching the solid electrolyte membrane between a fuel electrode and an air electrode from both sides. It has been.

This SOFC has the following merits.
First, the power density is higher and the power generation efficiency is higher than solid polymer fuel cells such as direct methanol fuel cells. In addition to hydrogen gas, all hydrocarbons such as carbon monoxide and methane can be used as they are as fuel gas. Furthermore, since the operating temperature is as high as about 800 to 1000 ° C., it is not necessary to use an expensive catalyst such as Pt (platinum) for the reaction.

By the way, as the fuel of SOFC, the structure which uses HC gas fuels, such as natural gas, as it is, is mainstream from the ease of fuel supply.
However, since the density of HC gas fuel is low, the portability in a high density state is poor. Along with this, there is a problem that a large volume of the fuel tank for storing HC gas fuel must be secured. Furthermore, there is a problem that the infrastructure for supplying HC gas fuel is not sufficiently prepared.

Therefore, a configuration is known in which a hydrocarbon-based liquid fuel (HC liquid fuel) such as gasoline or diesel fuel, which has a higher density than HC gas fuel and has a sufficient supply infrastructure, is used as SOFC fuel.
As such a configuration, there is known a configuration (first prior art) in which nitrogen or carbon dioxide is supplied (bubbled) into the HC liquid fuel, HC gas fuel evaporated together with the nitrogen and carbon dioxide is taken out, and supplied to the SOFC. It has been. Further, for example, as shown in Patent Document 1, a fuel vaporizer that vaporizes HC liquid fuel sprayed from an injector, and a reformer that generates a fuel gas containing hydrogen from the HC liquid fuel are provided. A configuration (second prior art) is known in which the liquefied HC gas fuel is supplied to the SOFC.

JP 2002-246047 A

However, the SOFC configuration using the above-described HC liquid fuel has the following problems.
In the former case (first prior art), the fuel gas supplied to the SOFC is a mixed gas of HC gas fuel evaporated from the HC liquid fuel and nitrogen, carbon dioxide, etc., so the HC gas supplied to the SOFC There is a problem that the fuel is lean and the output of SOFC is low.
In the latter case (second prior art), the price of the reformer itself is high, which causes an increase in cost.

  Furthermore, in these prior arts, the HC gas fuel is moved to an electrode of about 600 ° C. to 900 ° C. in a state of being converted into fuel gas. However, since the flow rate of the HC gas fuel is slow, the time during which the HC gas fuel stays in the carbon deposition temperature range of about 600 ° C. is increased, and the HC gas fuel is carbonized to deposit carbon on the supply pipes and electrodes of the HC gas fuel. . When carbon is deposited on the supply pipe, the supply pipe is clogged, while when the carbon is deposited on the SOFC electrode, the activity of the catalyst is lost and the SOFC may be deteriorated.

  Accordingly, the present invention has been made in view of the above-described circumstances, and provides a power generation apparatus for a solid oxide fuel cell that is low in cost and high in efficiency and high in output. It is another object of the present invention to provide a power generator for a solid oxide fuel cell that can use liquid fuel and can suppress carbon deposition due to carbonization of fuel gas at an electrode of a power generator. Furthermore, the present invention provides a power generator for a solid oxide fuel cell that can use precipitated carbon as a fuel, and can generate power again with liquid fuel after the deposited carbon is consumed.

In order to solve the above problems, the invention described in claim 1 is directed to one electrode (for example, the air electrode 8 in the embodiment) of the power generation body (for example, the power generation body 10 in the embodiment) of the solid oxide fuel cell. ) Is supplied with an oxidant gas (for example, the oxidant gas in the embodiment), and the first reaction chamber (for example, the reaction chamber 42 in the embodiment) in which the oxidant gas is reacted at the one electrode, and the power generator A second reaction chamber (for example, the reaction chamber 22 in the embodiment) for supplying fuel gas to the other electrode (for example, the fuel electrode 7 in the embodiment) and reacting the fuel gas in the other electrode; One reaction chamber and the second reaction chamber are provided in a temperature-controllable heating furnace (for example, the heating furnace 11 in the embodiment), and power is generated when the oxidant gas and the fuel gas react with each other in the power generator. The That the power generation device (for example, power generating apparatus 1 in the embodiment) A, the second reaction chamber, connects the injector for injecting liquids fuel toward the other electrode (e.g., an injector 55 in the embodiment) The gasification section (for example, the gasification section L3 in the embodiment) in which the liquid fuel injected from the injector is gasified by temperature control of the heating furnace is set in the second reaction chamber. To do.

  The invention described in claim 2 is characterized in that the injector pulse-injects the liquid fuel.

According to a third aspect of the present invention, the fuel gas is a dry hydrocarbon fuel that does not contain water vapor. By reacting the fuel gas with a component other than solid carbon as a fuel source, the fuel gas is reacted with the oxidant gas. It has the fuel gas consumption mode (for example, DO mode in embodiment) which performs electric power generation, It is characterized by the above-mentioned.

According to a fourth aspect of the present invention, the fuel gas is a fuel gas containing solid carbon, and the second reaction is performed in order to consume the solid carbon deposited in the second reaction chamber by carbonization of the fuel gas as a fuel source. It has a precipitated carbon consumption mode in which the temperature of the heating furnace is controlled to a predetermined temperature while the room is closed.

According to a fifth aspect of the present invention, the fuel gas is a fuel gas containing solid carbon, and it is determined whether or not the solid carbon is precipitated in the second reaction chamber by a carbonization of the fuel gas. A carbon deposition determination means (for example, a voltmeter in the embodiment) and a control unit (for example, a control panel in the embodiment) that performs switching control of the power generation mode based on the determination result of the carbon deposition determination means, The control unit includes a fuel gas consumption mode in which power generation is performed using a component other than solid carbon as a fuel source in the fuel gas when the carbon deposition determination unit determines that the amount of solid carbon deposited is less than a predetermined value. When the amount of solid carbon deposited is determined to be equal to or greater than a predetermined value, the mode is switched to a deposited carbon consumption mode in which power generation is performed using solid carbon deposited in the second reaction chamber as a fuel source.

According to the invention described in claim 1, by setting the gasification section for fuel gasifying the liquid fuel sprayed from the injector in the second reaction chamber, in the area until reaching the gasification section, The fuel can be moved in a liquid fuel state (for example, a liquid column state or a droplet state). Thereby, the mass transfer when the fuel reaches the power generation body can be easily performed. Furthermore, since liquid fuel has a higher density and less momentum diffusion than gas fuel, high-concentration gas fuel can be supplied to the power generation body by converting the fuel into fuel gas in the vicinity of the power generation body. Therefore, it is possible to provide a power generator for a solid oxide fuel cell with high output.
In addition, since it is possible to shorten the time until the liquid fuel is converted into fuel gas and reaches the power generator, that is, the staying time as the gas fuel, it is possible to suppress solid carbon deposition due to carbonization of the gas fuel.

  According to the invention described in claim 2, by spraying the liquid fuel at predetermined intervals by pulse injection, the injection amount and the injection time of the liquid fuel according to parameters such as the fuel gas concentration and temperature in the second reaction chamber. Therefore, compared with the case where liquid fuel is continuously sprayed, the remaining unreacted fuel gas can be suppressed and the power generation efficiency can be improved.

  According to the third aspect of the present invention, the dry hydrocarbon fuel is supplied to the second reaction chamber, thereby reducing the cost of the power generation device as compared with the conventional configuration in which reforming is performed using the reformer. Can be provided.

According to the invention described in claim 4, even if solid carbon is deposited from the fuel gas in the second reaction chamber, by closing the fuel gas path and sealing the second reaction chamber, Power generation can be performed when the precipitated solid carbon is oxidized. Along with this, the precipitated solid carbon can be removed. That is, even if the solid carbon is precipitated in the unlikely event the second reaction chamber can be removed while using the solid carbon as an energy source.

According to the fifth aspect of the present invention, components such as H ₂ , CO, and CH ₄ other than solid carbon contained in the fuel decomposition gas in the fuel gas consumption mode are obtained by performing the operation for switching the power generation mode by the control unit. In the precipitated carbon consumption mode, power generation can be performed using solid carbon deposited in the second reaction chamber as a fuel source. Therefore, it is possible to generate power efficiently and continuously while suppressing the remaining of unreacted fuel gas, so that power generation efficiency can be improved.

It is a schematic block diagram of the electric power generating apparatus in 1st Embodiment of this invention. It is a timing chart which shows the relationship of the operation timing of each valve, a heater, an air pump, an injector, and a heat exchanger from starting preparations to power generation start. It is a timing chart which shows the relationship of the operation timing of various apparatuses from the time of the normal power generation in DO mode to thermal self-sustained power generation. It is a timing chart which shows the relationship of the operation timing of various apparatuses at the time of transfer from DO mode to DC mode. It is a timing chart which shows the operation timing of various equipment in the case of stopping power generator 1. It is an important section expanded sectional view of a power generator. It is a graph which shows the fuel spray amount with respect to time. It is a graph which shows the electric power generation amount (voltage) with respect to time. It is sectional drawing of an electric power generation part, and is explanatory drawing which shows the behavior of an electric power generation part at the time of DC mode electric power generation. It is a graph which shows the fuel spray amount with respect to time of the electric power generating apparatus in the 1st modification of this invention. It is a graph which shows the voltage with respect to time of the electric power generating apparatus in the 1st modification of this invention. It is a graph which shows the fuel spray amount with respect to time of the electric power generating apparatus in the 2nd modification of this invention. It is a graph which shows the voltage with respect to time of the electric power generating apparatus in the 2nd modification of this invention. It is a schematic block diagram of the electric power generating apparatus in 2nd Embodiment of this invention. It is a schematic block diagram of the electric power generating apparatus in 3rd Embodiment of this invention. It is a schematic block diagram of the electric power generating apparatus in 4th Embodiment of this invention. It is an expanded sectional view of the electric power generation part in 4th Embodiment of this invention. It is a graph which shows the fuel density | concentration in the 2nd reaction chamber with respect to the position of the length direction of a power generation part at the time of supplying gas fuel to a power generation part, and the temperature in a power generation part. It is a graph which shows the electrical conversion efficiency and output with respect to the position of the length direction of a power generation part at the time of supplying gas fuel to a power generation part. It is a graph which shows the fuel density | concentration in the 2nd reaction chamber with respect to the position of the length direction of a power generation part at the time of supplying liquid fuel to a power generation part, and the temperature in a power generation part. It is a graph which shows the electrical conversion efficiency and output with respect to the position of the length direction of a power generation part at the time of supplying liquid fuel to a power generation part.

(Power generation device)
Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a schematic configuration diagram of a power generator.
As shown in FIG. 1, the power generation apparatus 1 generates power using a SOFC power generation body 10 and includes a heating furnace 11.
A heater (not shown) for controlling the temperature in the heating furnace 11 is provided in the heating furnace 11. As this heater, a boiler that obtains heat by burning fuel, an electric heater, or the like is preferably used. In addition, when using an electric heater, it is also possible to use the electric power generated with the power generator 1 as it is. In this embodiment, it is possible to form a soaking zone of, for example, about 800 ° C. to 900 ° C. in the central portion in the heating furnace 11.

  In the heating furnace 11, an oxidant gas circulation system 40 that is disposed on the upper side of the heating furnace 11 (upper side in FIG. 1) and through which the oxidant gas circulates is disposed on the lower side of the heating furnace 11 (lower side in FIG. 1). The fuel gas distribution system 20 through which the fuel gas flows and the power generator 10 sandwiched between the oxidant gas distribution system 40 and the fuel gas distribution system 20 are provided.

  The power generation body 10 has a disk shape, and includes a solid electrolyte membrane 9 made of YSZ (Ytria Stabilized Zirconia) or the like, and an air electrode 8 and a fuel electrode 7 so as to sandwich the solid electrolyte membrane 9 from the front and back surfaces. I have. As a material for forming the air electrode 8, for example, a sintered body of a gadolinium-based material and YSZ is used. On the other hand, as a material for forming the fuel electrode 7, for example, a sintered body of nickel and YSZ is used.

The oxidant gas flow system 40 includes an oxidant gas supply path 41 that supplies an oxidant gas toward the power generation body 10, a first reaction chamber 42 that causes the oxidant gas to react in the air electrode 8 of the power generation body 10, An oxidant gas discharge path 43 for discharging the oxidant gas exhaust gas from the inside of one reaction chamber 42 is configured to be able to communicate.
The oxidant gas supply path 41 is a tubular material made of, for example, quartz glass as a constituent material having heat resistance, low thermal conductivity, transparency, and the like, and is inserted into the heating furnace 11 from the end face on one end side of the heating furnace 11. And extends in the heating furnace 11 along the longitudinal direction. One end side (upstream side) of the oxidant gas supply path 41 is connected to an air pump 44 outside the heating furnace 11, and an oxidant gas such as oxygen or air is supplied from the air pump 44. ing.

  In the heating furnace 11, a heat exchanger (H_Ex) 45 is connected to the oxidant gas supply path 41. The heat exchanger 45 exchanges heat between the oxidant gas supplied from the air pump 44 and flowing through the oxidant gas supply path 41 and the exhaust gas of the oxidant gas used for power generation in the first reaction chamber 42. This is for controlling (heating) the temperature of the oxidant gas. Further, a supply side valve (Va_in) 46 capable of sealing the inside of the oxidant gas supply path 41 is provided downstream of the heat exchanger 45 in the oxidant gas supply path 41.

  A first reaction chamber 42 made of quartz glass or the like is connected to the other end side (downstream side) of the oxidant gas supply path 41 in the soaking zone at the center of the heating furnace 11. The first reaction chamber 42 has a bottomed cylindrical shape that opens downward, and is arranged in a state in which the axial direction thereof coincides with the height direction of the heating furnace 11 (vertical direction in FIG. 1). Yes.

  The oxidant gas discharge passage 43 is a tubular tube made of quartz glass or the like, like the oxidant gas supply passage 41, and is connected to the opposite side of the oxidant gas supply passage 41 with the first reaction chamber 42 interposed therebetween. The exhaust gas of the oxidant gas used for power generation circulates in the first reaction chamber 42. The oxidant gas discharge path 43 is provided with a discharge side valve (Va_out) 47 that can seal the inside of the oxidant gas discharge path 43. That is, the inside of the first reaction chamber 42 is sealed by closing the discharge side valve 47 and the supply side valve 46 described above. A high-temperature air combustor 48 for increasing the temperature of the exhaust gas supplied to the heat exchanger 45 is connected to the other end side (downstream side) of the oxidant gas discharge path 43.

  The high-temperature air combustor 48 is connected to an exhaust gas discharge path 50 that is drawn from the upper part of the heating furnace 11 to the outside of the heating furnace 11 and through which exhaust gas of oxidant gas and fuel gas flows. A two-way valve (V_HEx) 51 capable of switching the exhaust gas flow path is connected to the exhaust gas discharge path 50, and is supplied into the first reaction chamber 42 by performing switching control of the two-way valve 51. The temperature of the oxidant gas can be adjusted. That is, when it is necessary to raise the temperature of the oxidant gas, the exhaust gas is circulated through the heat exchanger 45 and then discharged to the outside. On the other hand, when it is not necessary to raise the temperature of the oxidant gas, the exhaust gas discharge path 50 The exhaust gas is discharged directly from the outside.

  On the other hand, the fuel gas distribution system 20 is supplied with fuel gas toward the power generation body 10, and reacts with the fuel gas in the power generation body 10 (fuel electrode 7), and fuel from the second reaction chamber 22. A fuel gas discharge path 23 for discharging gas exhaust gas (for example, carbon dioxide, water, unreacted fuel gas, etc.) is configured to be able to communicate.

  The second reaction chamber 22 has a bottomed cylindrical shape made of quartz glass or the like. The second reaction chamber 22 is formed on one end side (lower side) and on the other end side (upper side). Also has a large-diameter portion 22b with an enlarged inner diameter, and opens upward. The second reaction chamber 22 is arranged in a state where the axial direction thereof coincides with the height direction of the heating furnace 11. Specifically, one end side (bottom side) of the small diameter portion 22a of the second reaction chamber 22 protrudes from the lower portion of the heating furnace 11 and the other end side is held as desired in the heating furnace 11. Thereby, a temperature gradient is formed in the second reaction chamber 22 so as to gradually increase in temperature along the axial direction of the second reaction chamber 22 from the bottom side of the second reaction chamber 22 to the opening side. A temperature controller 52 and a pressure controller 53 for detecting the temperature and pressure in the second reaction chamber 22 are provided in the second reaction chamber 22. And the space which covers the electric power generation body 10 by each reaction chamber 22 and 42 comprises the electric power generation part 54 of this embodiment. The power generation apparatus 1 also includes a load (not shown) such as a voltmeter (carbon deposition determination means) that detects the generated voltage and a motor that applies a voltage to flow current.

  The fuel gas discharge passage 23 has a tubular shape made of quartz glass or the like, and the exhaust gas of the fuel gas supplied for power generation circulates in the second reaction chamber 22. One end of the fuel gas discharge path 23 is connected to the second reaction chamber 22, and the other end side (downstream side) is connected to the exhaust gas discharge path 50 via the high-temperature air combustor 48 described above. That is, the exhaust gas of the fuel gas is combined with the exhaust gas of the oxidant gas in the high-temperature air combustor 48, and the unreacted fuel gas contained in the exhaust gas burns to raise the temperature of the exhaust gas of the oxidant gas. Yes. Further, the fuel gas discharge path 23 in the fuel gas distribution system 20 is provided between the reaction chamber 22 and the high-temperature air combustor 48 in the fuel gas distribution system 20 (from the second reaction chamber 22 to the fuel gas discharge path 23). Is provided with a fuel side valve 27 (Vf).

  Here, an injector 55 is connected to the bottom of the second reaction chamber 22. The injector 55 sprays liquid fuel from the bottom side of the second reaction chamber 22 toward the power generator 10, and is connected to the bottom of the second reaction chamber 22, and one end (spray side) of the second reaction chamber 22 is the second reaction. The inside of the second reaction chamber 22 is held as desired from the bottom of the chamber 22. That is, the injector 55 is connected to a portion of the small diameter portion 22 a that protrudes from the heating furnace 11 and is held outside the heating furnace 11. The injector 55 is configured to spray the liquid fuel along the height direction of the heating furnace 11 from the lower side to the upper side of the heating furnace 11.

  The other end of the injector 55 is connected to a fuel tank 57 via a liquid fuel supply path 56. The fuel tank 57 is filled with HC liquid fuel such as alcohol, gasoline or diesel fuel. The injector 55 is connected to an injector controller (INJ controller) 58 for adjusting the spray amount, spray interval and the like of the liquid fuel from the injector 55 based on a signal output from a control panel (not shown). ing.

In addition, an inert gas supply path 30 for supplying an inert gas is connected to the second reaction chamber 22 via an inert gas valve (Vn) 31 outside the heating furnace 11. An inert gas supply source (not shown) is connected to the upstream side of the inert gas supply path 30, and an inert gas such as nitrogen (N ₂ ) is supplied into the second reaction chamber 22.
In addition, the electric power generating apparatus 1 controls the opening / closing control of each valve 27, 31, 46, 47, the switching control of the two-way valve 51, the temperature control in the heating furnace 11, the pressure control, the spray amount from the injector 55, the spray interval, and the like. A control panel (not shown) that performs control and the like is provided.

(Power generation method)
Next, a power generation method using the above-described power generation apparatus will be described. Here, in the power generation apparatus of this embodiment, DO (direct oxidation) mode (fuel gas consumption) in which power generation is performed using components such as H ₂ , CO, and CH ₄ other than solid carbon contained in the fuel cracked gas as a fuel source. Mode) and a DC (direct carbon) mode (deposited carbon consumption mode) in which power is generated using solid carbon deposited in the second reaction chamber 22 as a fuel source.

(From start-up preparation to power generation start)
FIG. 2 is a timing chart showing the relationship of operation timings of valves, heaters, air pumps, injectors, heat exchangers and the like (hereinafter referred to as various devices) from preparation for starting up to the start of power generation.
First, as shown in FIG. 2, at time T1, the power generator 1 is operated to replace the inside of the second reaction chamber 22 with N ₂ (replacement step). Specifically, the inert gas valve 31 is opened (time T2), the fuel side valve 27 is opened (time T3), and the inert gas is supplied from the supply source of the inert gas into the second reaction chamber 22. The control panel closes the valves 31 and 27 (time T4, 5) after a predetermined time has elapsed or when it is determined that the oxygen concentration in the second reaction chamber 22 has become a predetermined value or less. Stop the supply of inert gas. Thereby, N ₂ substitution in the second reaction chamber 22 is completed.

  Next, at time T6, a temperature raising signal is output from the control panel to the heater of the heating furnace 11, and the heater is operated to raise the temperature in the heating furnace 11 (temperature raising step). A soaking zone having a predetermined command temperature: Tx (about 600 ° C. to 800 ° C.) is formed in the central portion of the heating furnace 11, and the temperature decreases as it goes from the soaking zone to the outside of the heating furnace 11. A temperature gradient occurs. Note that the control panel performs feedback control so that the temperature in the heating furnace 11 is maintained at Tx until the thermal self-sustaining described later is reached (broken line area A in FIG. 2).

(During DO mode power generation)
Next, when the temperature in the heating furnace 11 reaches Tx, DO mode power generation is started. Specifically, the control panel operates the air pump 44 to supply the oxidizing gas into the first reaction chamber 42 (time T7). Further, the supply side valve 46 and the discharge side valve 47 are opened (time T8, 9), and the two-way valve 51 is switched so that the exhaust gas flows toward the heat exchanger 45 (time T10). The supply pressure of the oxidant gas is preferably set slightly higher than atmospheric pressure.
At time T <b> 11, the liquid fuel starts to be sprayed continuously from the fuel tank 57 through the injector 55 toward the first reaction chamber 22.

Here, the oxidant gas delivered from the air pump 44 is supplied to the first reaction chamber 42 through the oxidant gas supply path 41.
On the other hand, the liquid fuel supplied to the injector 55 is sprayed vertically from the bottom side of the second reaction chamber 22 toward the power generator 10, that is, from the bottom to the top of the heating furnace 11.

FIG. 6 is an enlarged cross-sectional view of a main part of the power generation device according to the first embodiment of the present invention.
As shown in FIG. 6, the liquid fuel sprayed from the injector 55 evaporates due to a temperature gradient or the like generated along the height direction of the heating furnace 11 (the axial direction of the second reaction chamber 22), and hydrocarbon gas The fuel gas is converted into fuel (HC gas fuel) and reaches the power generator 10. Specifically, the liquid fuel sprayed from the injector 55 is first sprayed in a liquid column state. That is, a region projecting outside the heating furnace 11 near the spray hole (not shown) of the injector 55, for example, on the small-diameter portion 22a side of the reaction chamber 22, is set as the liquid column section L1, and the liquid column section L1 is liquid. The fuel is moved in a liquid column state.

By the way, in the middle part of the second reaction chamber 22, for example, in the region where the small diameter portion 22a is inserted into the heating furnace 11 (droplet section L2 in FIG. 6), compared to the liquid column section L1 in the second reaction chamber 22, The temperature in the second reaction chamber 22 is high. As a result, the liquid fuel that has reached the droplet section L2 in the liquid column state is split into innumerable droplets from the liquid column state, and a part thereof is evaporated.
Furthermore, in the large-diameter portion 22b of the second reaction chamber 22, for example, in a soaking zone (gasification section L3) in the center of the heating furnace 11, the temperature in the second reaction chamber 22 is higher than that of the droplet section L2. As a result, the liquid fuel that has reached the gasification section L3 in the form of liquid droplets is all evaporated and fuel gasified into fuel gas while reaching the fuel electrode 7 of the power generator 10 from the vicinity of the power generator 10. . In this embodiment, since only the liquid fuel is supplied to the second reaction chamber 22, the liquid fuel is converted into fuel gas, so that the components of the fuel gas do not contain water vapor, and the dry hydrocarbon It becomes gas fuel. The liquid column section L1, the droplet section L2, and the gasification section L3 described above are adjusted in addition to the temperature gradient in the reaction chamber 22, the temperature of the gas in the reaction chamber 22, the pressure, the temperature of the liquid fuel, and the viscosity. It can be changed as appropriate by adjusting parameters such as the nozzle hole diameter of the injector 55, the spray pressure, and the gas-liquid surface tension.

The oxidant gas supplied to the first reaction chamber 42 becomes oxygen ions in the air electrode 8 of the first reaction chamber 42 by a catalytic reaction. Then, oxygen ions generated in the air electrode 8 pass through the solid electrolyte membrane 9 and move to the fuel electrode 7 in the second reaction chamber 22.
On the other hand, the fuel sprayed from the injector 55 passes through the liquid column section L1, the droplet section L2, and the gasification section L3 as described above, is converted into fuel gas, and reaches the fuel electrode 7 of the power generator 10. Then, when the fuel gas that has reached the fuel electrode 7 and the oxygen ions that have moved to the fuel electrode 7 react at the fuel electrode 7, electricity is generated by releasing electrons (H ₂ + O ²⁻ → H ₂ O + 2e ⁻ ).

  In the second reaction chamber 22, the liquid fuel is supplied, or the liquid fuel is vaporized and expanded in volume, whereby the pressure in the second reaction chamber 22 increases. Therefore, the control panel performs feedback control (broken line region B in FIG. 2) to open and close the fuel side valve 27 so that the pressure in the second reaction chamber 22 is maintained near the predetermined pressure Px during power generation. (Time T12). Specifically, when the pressure Pf detected by the pressure controller 53 is larger than the predetermined pressure Px (Pf> Px), the fuel side valve 27 is opened and the fuel gas discharge passage 23 is opened in the second reaction chamber 22. Exhaust gas of fuel gas. Then, after the fuel side valve 27 is opened, when the pressure Pf in the second reaction chamber 22 again falls below the predetermined pressure Px (P ≦ Px), the fuel side valve 27 is closed again, and thereafter the fuel side valve 27 Repeat opening and closing. In the present embodiment, the effect of transporting the fuel gas to the surface of the fuel electrode 7 is enhanced by the turbulent flow generated by the pressure increase accompanying the vaporization of the liquid fuel. Therefore, compared to the prior art in which vaporized fuel gas is sent to the fuel electrode 7 at a high speed in order to obtain the same effect, it is not necessary to use a high performance pump or the like, so that the manufacturing cost and maintenance load are reduced, and the apparatus is small and light. Can be realized.

The oxidant gas exhaust gas used for power generation in the first reaction chamber 42 is supplied to the high-temperature air combustor 48 through the oxidant gas discharge passage 43.
On the other hand, the exhaust gas of the fuel gas provided for power generation in the second reaction chamber 22 is also supplied to the high-temperature air combustor 48 through the fuel gas discharge path 23 in the same manner as the oxidant gas. When the fuel gas exhaust gas is supplied to the high-temperature air combustor 48, the unreacted fuel gas contained in the fuel gas exhaust gas burns, and the temperature of the oxidant gas exhaust gas is raised. The heated exhaust gas is supplied to the heat exchanger 45 through the exhaust gas discharge path 50, and heat exchange is performed with the oxidant gas flowing in the oxidant gas supply path 41 in the heat exchanger 45. The oxidant gas flowing in the oxidant gas supply path 41 is supplied to the first reaction chamber 42 while being heated by the heat exchanger 45, while the exhaust gas passes through the exhaust gas discharge path 50 to the outside. Discharged.

FIG. 3 is a timing chart showing the relationship of operation timings of various devices from normal power generation to thermal self-sustained power generation in the DO mode.
Here, in the power generation device 1 of the present embodiment, a current is passed (load is applied) in a state where the open circuit voltage OCV is about 0.7V. In this case, as shown in FIG. 3, the control panel controls the supply flow rates of the fuel gas and the oxidant gas so that the voltage can be maintained at about 0.7 V even after the current is passed (broken line region C in FIG. 2). ). Specifically, the control panel has a map of the oxidant gas and the fuel gas corresponding to the temperature in the second reaction chamber 22, and calculates the flow rate based on this map. The control panel increases or decreases the flow rates of the oxidant gas and the fuel gas based on the calculated flow rates (time T13, 14). Thus, by controlling the supply flow rates of the fuel gas and the oxidant gas so that the open circuit voltage OCV is about 0.7 V, the film deterioration of the power generation body 10 is suppressed, and the power generation characteristics are maintained well. can do.

(Thermal independent power generation)
By the way, in the electric power generating apparatus 1 of this embodiment, the temperature of the reaction chambers 22 and 42 rises with the heat which generate | occur | produces regarding electric power generation. In this case, if the power generation is continued, the power generation amount and the heat radiation amount are balanced, and the heat generation becomes independent at a temperature at which the power generation is optimally performed (for example, the predetermined temperature Tx = 600 ° C. to 900 ° C.). The temperature in the reaction chambers 22 and 42 is maintained at a predetermined temperature without being consumed, so that the temperature is maintained.

  Therefore, as the power generation continues, as shown in FIG. 3, the heater output required to maintain the predetermined temperature Tx decreases due to heat generated from the second reaction chamber 22. Then, when the supply flow rates of the fuel gas and the oxidant gas are constant, it is determined that the heat self-sustainment is completed when the external power for maintaining the predetermined temperature Tx becomes unnecessary (time T15).

  When the required output (power generation amount) increases after completion of the heat self-supporting, the supply flow rate of the fuel gas and the oxidant gas is increased, and feedback control is performed so as to maintain the necessary power (time T16, 17). In this state, DO mode power generation as described above can be performed without consuming extra energy such as temperature control by the heater. Thereafter, at time T18, the control panel performs switching control of the two-way valve 51 in order to keep the temperature in the second reaction chamber 22 constant in the vicinity of the predetermined temperature Tx (broken line region D in FIG. 3). That is, when the temperature Tc in the second reaction chamber 22 rises from the predetermined temperature Tx as the output increases, the heat exchanger 45 is used to cool the oxidant gas supplied into the first reaction chamber 42. The exhaust gas is discharged directly to the outside without circulating it. Thereafter, when the temperature Tc in the second reaction chamber 22 falls below the predetermined temperature Tx, the exhaust gas is circulated through the heat exchanger 45 in order to heat the oxidant gas supplied to the first reaction chamber 42. .

  When the liquid fuel undergoes phase change by heating and is gasified, heat exchange with the heat reservoir in the second reaction chamber 22 is necessary, and at that time, the latent heat of vaporization corresponding to the heat capacity of the liquid fuel is generated in the second reaction chamber 22. Deprived of. That is, the second reaction chamber 22 is also cooled by this. Therefore, it becomes easier to maintain the temperature Tc in the second reaction chamber 22 near the predetermined temperature Tx.

(DC mode power generation)
FIG. 9 is a cross-sectional view of the power generation unit and is an explanatory diagram illustrating the behavior of the power generation unit during DC mode power generation. In FIG. 9, the description of the peripheral members of each reaction chamber is omitted for easy understanding.
By the way, as shown in FIG. 9, in the 2nd reaction chamber 22, the unreacted fuel gas etc. which remain without reacting with the electric power generation body 10 may carbonize, and carbon may precipitate not a little. Specifically, the inner peripheral wall around the droplet section L2, which is relatively cooler than the gasification section L3, and the low temperature region Q such as the vicinity of the fuel gas discharge passage 23 is a carbon deposition temperature region (for example, about 600 ° C.). In this low temperature region Q, unreacted fuel gas or the like is carbonized and carbon is likely to precipitate. In this case, the deposited carbon may scatter in the reaction chamber 22 and cover the reaction field of the fuel electrode 7. Furthermore, there is a possibility that the power generation performance of the power generation body 10 may be reduced together with the carbon deposited in the reaction field of the fuel electrode 7 with DO power generation. Note that when the power generation performance decreases, the amount of heat generated with respect to power generation decreases, and the temperature in the second reaction chamber 22 also decreases.

FIG. 4 is a timing chart showing the relationship of the operation timings of various devices when shifting from the DO mode to the DC mode. FIG. 7 is a graph showing the amount of fuel spray with respect to time, and FIG. 8 is a graph showing the amount of power generation (voltage) with respect to time.
When a predetermined amount of carbon is deposited in the reaction field of the fuel electrode 7, the power generator 1 is switched to the DC mode as shown in FIG. Specifically, as shown in FIGS. 7 and 8, the control unit determines whether or not carbon deposition has occurred depending on whether or not the voltage of the power generation device 1 has decreased to a value (for example, a predetermined voltage Vx = approximately 0.6 V) or less. to decide. That is, when it is determined that the voltage of the power generation device 1 has become equal to or lower than the predetermined voltage, it is determined that the deposited carbon covers the fuel electrode 7 and the power generation performance is degraded, and the mode is switched from the DO mode to the DC mode. (See time t in FIG. 8). Note that it is not preferable to continue the power generation at a voltage lower than the predetermined voltage Vx because the film deterioration of the power generation body 10 is promoted.

First, as shown in FIG. 4, a DC mode start signal is output from the control panel toward the fuel side valve 27 and the injector controller 58 of the injector 55, and the supply of liquid fuel by the injector 55 is stopped (time T19). Then, the fuel side valve 27 provided in the fuel gas discharge passage 23 is closed to close the fuel gas circulation system 20 (time T20). At this time, the oxidant gas is continuously supplied to the oxidant gas flow system 40.
Then, after the fuel side valve 27 is closed, a temperature rising signal is output from the control panel to the heater of the heating furnace 11, the temperature of the second reaction chamber 22 is increased, and the temperature Tc in the second reaction chamber 22 is increased. It is maintained in a soaking zone at a predetermined temperature TDCx (for example, around TDCx = 900 ° C.) (time T21). Thereafter, when the temperature Tc in the second reaction chamber 22 exceeds the predetermined temperature TDCx, the control panel outputs a stop signal to the heater and stops the operation of the heater (time T22).

As shown in FIG. 9, in the DC mode, carbon (C) precipitated in the reaction chamber 22 and carbon dioxide (CO ₂ ) remaining as exhaust gas are combined (CO ₂ + C), and carbon monoxide (CO ) (CO ₂ + C → 2CO). The carbon monoxide (CO) reacts with oxygen ions (O) that have passed through the solid electrolyte membrane 9 and moved to the fuel electrode 7 to become carbon dioxide (CO ₂ ). When this carbon dioxide (CO ₂ ) is generated, power is generated (CO + O ²⁻ → CO ₂ + 2e ⁻ ).
As a result, even if carbon is deposited in the second reaction chamber 22 due to carbonization of unreacted fuel gas or the like, the fuel gas flow system 20 is sealed to make the second reaction chamber 22 sealed. Thus, power generation can be performed when the deposited carbon is oxidized. Along with this, the deposited carbon can be removed. That is, even if carbon is deposited in the second reaction chamber 22, it can be removed using this carbon as an energy source.

Here, also in the DC mode, the temperature in the reaction chambers 22 and 42 rises due to heat generated with respect to power generation. Therefore, the switching control of the two-way valve 51 is performed similarly to the above-described DO mode (time T23).
Further, the feedback control for opening and closing the fuel side valve 27 is performed in the same manner as in the DO mode described above so that the pressure in the second reaction chamber 22 is maintained near the predetermined pressure Px during power generation (time T24).

  If the carbon in the second reaction chamber 22 continues to be consumed by DC mode power generation, the voltage gradually decreases. That is, the carbon in the second reaction chamber 22 is removed, and the power generation body 10 can exhibit the desired power generation performance again.

  Therefore, the control panel determines whether or not the carbon in the second reaction chamber 22 is sufficiently consumed depending on whether or not the power generation amount (voltage) of the power generation device has decreased to a predetermined voltage Vx (for example, 0.6 V) or less. Judging. That is, when it is determined that the voltage of the power generation device 2 has become equal to or lower than the predetermined voltage, it is determined that the carbon is sufficiently consumed and the power generation body 10 can exhibit the desired power generation performance again, and the DC mode is switched to the DO mode. Switch. Specifically, similarly to the method for switching from the DO mode to the DC mode described above, the temperature in the second reaction chamber 22 is changed to a predetermined temperature Tx (about 600 ° C. to about 800 ° C.) by the heater (time T25). ), The fuel spray is started to be sprayed by the injector 55 (time T26), and the fuel side valve 27 is opened (time T27). Thereby, power generation can be performed in a state where desired power generation performance is obtained again by the DO mode.

(How to stop)
FIG. 5 is a timing chart showing operation timings of various devices when the power generation device 1 is stopped.
When stopping the operation of the power generator 1 from the DO mode, first, spraying by the injector 55 is stopped (time T28). Then, each valve | bulb 27,46,47, a heater, and the air pump 44 are stopped (time T29-33), and the power supply of the electric power generating apparatus 1 is stopped in time T34. Even when the power generation device 1 is stopped from the DC mode, the power generation device 1 is similarly stopped by stopping the power supply of the power generation device 1 after stopping the valves 27, 46, 47, the heater and the air pump 44. can do.

Thus, in the above-described embodiment, the power generation unit 54 is disposed at the center of the heating furnace 11, and the injector 55 that sprays liquid fuel into the second reaction chamber 22 is connected to the bottom of the second reaction chamber 22, The liquid fuel is sprayed toward the power generation body 10. And the gasification section L3 which gasifies the liquid fuel sprayed from the injector 55 by temperature control of the heating furnace 11 is set in the second reaction chamber 22.
According to this configuration, by setting the gasification section L3 in the reaction chamber 22, in the region until reaching the gasification section L3, the fuel is in a liquid fuel state (for example, a liquid column state or a droplet state). Can be moved. Thereby, the mass transfer when the fuel reaches the power generation body 10 can be easily performed. Furthermore, since liquid fuel has a higher density and less momentum diffusion than gas fuel, high-concentration gas fuel can be supplied to the power generation body 10 by converting the fuel into fuel gas in the vicinity of the power generation body 10. Therefore, the high-power SOFC power generator 1 can be provided.

  Since the fuel can be moved in the reaction chamber 22 in the state of liquid fuel until the fuel reaches the gasification section L3, the mass transfer when the fuel reaches the power generation body 10 is promptly performed. Can do. Thereby, the time until the liquid fuel is converted into fuel gas and reaches the power generator 10, that is, the staying time for staying as the gas fuel can be shortened. Therefore, carbon deposition due to carbonization of the gas fuel that occurs when the gas fuel stays in the vicinity of the carbon deposition temperature for a long time can be suppressed.

Further, by spraying the liquid fuel from the lower side of the heating furnace 11 to the upper side by the injector 55 connected to the second reaction chamber 22 outside the heating furnace 11, the thermal convection generated in the reaction chamber 22 is It becomes difficult to transmit to the injector 55 connected below the reaction chamber 22. Thereby, since it can prevent that the injector 55 becomes high temperature, precipitation of carbon can be suppressed and clogging of the spray hole of the injector 55 can be prevented.
In addition, since the injector 55 can be directly connected to the reaction chamber 22, it is possible to provide the power generation device 1 that is less expensive than the conventional configuration in which fuel is supplied via the reformer.
Therefore, it is possible to provide the SOFC power generation apparatus 1 that can use liquid fuel and can suppress carbon deposition due to carbonization of the gas fuel at the electrode of the power generation body 10.

In particular, in the present embodiment, by performing a switching operation of the power generation mode by the control panel, H ₂ , CO, CH _{4 and the} like contained in the fuel are precipitated in the second reaction chamber 22 in the DC mode and in the DO mode. It is possible to generate electricity using each carbon as a fuel source. Therefore, it is possible to generate power efficiently and continuously while suppressing the remaining of unreacted fuel gas, so that power generation efficiency can be improved.

(First modification)
Next, a modification of the first embodiment will be described. FIG. 10 is a graph showing the fuel spray amount with respect to time, and FIG. 11 is a graph showing voltage with respect to time. In the following description, the same configurations and methods as those in the first embodiment described above are denoted by the same reference numerals, and description thereof is omitted.
This modification differs from the first embodiment described above in that liquid fuel is supplied by pulse spraying in the DO mode. Specifically, as shown in FIGS. 2, 10, and 11, at time T11, a predetermined amount of liquid fuel is sprayed at predetermined intervals (for example, time t1). Thereby, when the fuel gas that has reached the fuel electrode 7 and the oxygen ions that have moved to the fuel electrode 7 react at the fuel electrode 7, electricity is generated by releasing electrons. The fuel spray amount, spray interval, and the like can be changed as appropriate.
When it is determined that the voltage of the power generation device 1 has become equal to or lower than the predetermined voltage, it is determined that the deposited carbon covers the fuel electrode 7 and the power generation performance is degraded, and as in the first embodiment. The mode is switched from the DO mode to the DC mode (time t in FIGS. 10 and 11).

  According to this configuration, the liquid fuel is sprayed at predetermined intervals by pulse spraying, so that the liquid fuel spray amount and spray time can be easily set according to parameters such as the fuel gas concentration and temperature in the second reaction chamber 22. Since it can be adjusted, it is possible to improve the power generation efficiency by suppressing the remaining unreacted fuel gas as compared with the case where liquid fuel is continuously sprayed.

(Second modification)
Next, a second modification of the present invention will be described. FIG. 12 is a graph showing the fuel spray amount with respect to time, and FIG. 13 is a graph showing voltage with respect to time.
In the first embodiment and the first modification described above, the carbon deposition amount in the second reaction chamber 22, that is, the case where the DO mode and the DC mode are switched in accordance with the voltage drop due to the carbon deposition has been described. In the example, the DO mode and the DC mode are switched according to the power generation time with respect to the total spray amount of the liquid fuel in the DO mode.

  As shown in FIGS. 2, 12, and 13, at time T <b> 11, a predetermined amount of liquid fuel is sprayed at predetermined intervals for a predetermined time (for example, time S). Thereby, when the fuel gas that has reached the fuel electrode 7 and the oxygen ions that have moved to the fuel electrode 7 react at the fuel electrode 7, electricity is generated by releasing electrons.

  Here, assuming that the number of sprays (number of pulses) in one DO mode is N, the spray rate (mol / sec) per pulse is L, and the spray time (sec) for each pulse is S, one time The total spray amount in the DO mode is (N · L · S). For example, the fuel is approximated to C × Hr, the current is I (C / sec), and the Faraday constant is F (C / mol). The power generation time t2 (sec) of one cycle (DO mode and DC mode each time) required to completely consume the remaining fuel is expressed as t2 = (2X + 2Y) × N · L · S × 2F Can do.

The control panel has a map of the power generation time t2 with respect to the total spray amount of the liquid fuel and the power generation time t3 in the DO mode, and determines the switching timing from the DO mode to the DC mode based on this map. Specifically, the control panel determines whether or not the power generation time from the start of liquid fuel spraying has exceeded t3. When it is determined that the power generation time t3 has been exceeded, it is determined that all of H ₂ , CO, CH _{4 and the} like contained in the fuel gas existing in the second reaction chamber 22 have reacted, and the mode is shifted from the DO mode to the DC mode. To do. Transition to the DC mode can be performed by the same method as in the first embodiment described above.

  According to this configuration, unlike the first embodiment and the first modification, useless fuel is sprayed by performing switching determination between the DO mode and the DC mode according to the power generation time with respect to the total spray amount of liquid fuel. Without changing to the DC mode. As a result, the remaining unreacted fuel gas can be suppressed and the power generation efficiency can be further improved. In this case, since the total spray amount (total pulse area) of the liquid fuel in the DO mode is smaller in the second modification than in the first modification described above, the output is low, but no reaction occurs at the time of switching the power generation mode. Therefore, the highly efficient power generator 1 can be provided. On the other hand, in the first modified example described above, the total spray amount (total pulse area) of the liquid fuel during the DO mode is larger than in the second modified example. 1 can be provided. In this modification, a reducing gas (for example, carbon dioxide) or the like may be supplied into the second reaction chamber 22 before switching from the DO mode to the DC mode.

(Second Embodiment)
Next, a second embodiment of the present invention will be described. FIG. 14 is a schematic configuration diagram of a power generation device according to the second embodiment. In the following description, the same configurations and methods as those in the first embodiment described above are denoted by the same reference numerals, and description thereof is omitted.
The power generation apparatus 100 of this embodiment is different from the above-described embodiment in that water vapor is supplied into the second reaction chamber 122 together with the liquid fuel. Specifically, as shown in FIG. 14, in the power generation device 100, the water injector 101 is connected to the bottom of the small diameter portion 22 a in the second reaction chamber 122. A water tank 102 as a water supply source is connected to the water injector 101, and water is supplied from the water tank 102 into the second reaction chamber 122 via the water injector 101. . The water injector 101 is connected to an injector controller (INJ controller) 103 for adjusting the spray amount, spray interval and the like of water from the water injector 101 based on a signal output from a control panel (not shown). Has been.

In this case, in the DO mode, liquid fuel is sprayed from the injector 55 toward the second reaction chamber 122 and water is sprayed from the water injector 101. Then, the water sprayed from the water injector 101 evaporates due to a temperature gradient or the like generated along the height direction of the heating furnace 11 and moves toward the power generator 10 as water vapor. At this time, hydrogen is generated by a reforming reaction between the hydrocarbon contained in the fuel gas gasified in the second reaction chamber 122 and water vapor (CnH _{2n + 2} + nH ₂ O → nCO + (n + 2) H ₂ )) . As a result, when the steam-reformed fuel gas that reaches the fuel electrode 7 and the oxygen ions that have moved to the fuel electrode 7 react at the fuel electrode 7, electricity is generated by releasing electrons.

  According to this configuration, the same effects as those of the first embodiment described above can be achieved, and steam reforming can be performed by supplying liquid fuel and water into the second reaction chamber 122 at the same time. In addition to reducing costs, energy conversion loss during power generation is small and highly efficient power generation becomes possible.

(Third embodiment)
Next, a third embodiment of the present invention will be described. FIG. 15 is a schematic configuration diagram of a power generation device according to the third embodiment. In the following description, the same configurations and methods as those in the first embodiment described above are denoted by the same reference numerals, and description thereof is omitted.
The power generation apparatus 200 according to the present embodiment is different from the first embodiment described above in that a plurality of power generation units 254a and 254b are provided in the heating furnace 11. Specifically, as illustrated in FIG. 15, the power generation apparatus 200 includes a DC power generation unit 254 a and a DO power generation unit 254 b in the heating furnace 11. The DC power generation unit 254a has the same configuration as the power generation unit 54 (see FIG. 1) of the first embodiment described above, and is a power generation unit for mainly performing the DC mode power generation described above. The DO power generation unit 254b is a power generation unit mainly for performing the above-described DO mode power generation. Similarly to the DC power generation unit 254a, the first reaction chamber 242 in which an oxidant gas is supplied to the upper side of the heating furnace 11, and the heating The second reaction chamber 222 is supplied with fuel gas to the lower side of the furnace 11, and the power generator 10 is sandwiched between the opening edges of both the reaction chambers 242 and 222. The first reaction chambers 42, 242 between the power generation units 254 a, 254 b are connected via an oxidant gas valve 201, while the second reaction chambers 22, 222 are connected via a fuel gas valve 202.

  Further, a two-way valve or the like is used for the supply side valve 146 of the oxidant gas supply path 41, and the supply side valve 146 bypasses the DC power generation unit 254a and is directly connected to the DO power generation unit 254b. A gas bypass route 204 is provided. That is, by performing switching control of the supply side valve 146, the oxidant gas is supplied to the DO power generation unit 254b via the DC power generation unit 254a or directly to the DO power generation unit 254b without passing through the DC power generation unit 254a. An oxidant gas can be supplied.

When generating power with the power generation apparatus 200, first, the temperature inside the heating furnace 11 is raised to about 600 ° C. with a heater, and then the supply side valve 146 is switched so that the oxidant gas is supplied only to the DO power generation unit 254b. Liquid fuel is sprayed from the injector 55 into the second reaction chamber 22 of the DC power generation unit 254a. In this case, since the inside of the second reaction chamber 22 is in a carbon deposition temperature region of about 600 ° C., the fuel gas sprayed in the second reaction chamber 22 is carbonized and actively deposited in the second reaction chamber 22. . Accordingly, H ₂ , CO, CH _{4 and the} like thermally decomposed from the fuel gas are supplied into the second reaction chamber 222 of the DO power generation unit 254b through the fuel gas discharge path 23.

At this time, the DO power generation unit 254b performs the above-described DO mode power generation using the fuel gas (H ₂ , CO, CH ₄ or the like) supplied into the second reaction chamber 222 and the oxidant gas.
On the other hand, when a predetermined amount of carbon is deposited in the DC power generation unit 254a, the inside of the heating furnace 11 is heated to about 800 ° C. with a heater, and then the spraying of liquid fuel is stopped and the fuel gas valve 202 is closed. Further, the supply side valve 147 of the oxidant gas supply path 41 is switched to supply the oxidant gas to the DC power generation unit 254a. Then, carbon precipitated in the second reaction chamber 22 of the DC power generation unit 254a and carbon dioxide remaining in the second reaction chamber 22 are combined to become carbon monoxide. The carbon monoxide reacts with oxygen ions that have moved to the fuel electrode 7 to generate DC mode power generation.

  As described above, in the present embodiment, the DC power generation unit 254a performs DC mode power generation, and the DO power generation unit 254b performs DO mode power generation. Thus, the same effects as those of the first embodiment can be achieved. In the present embodiment, the power generation body 10 of the DO power generation unit 254b is not limited to the SOFC.

(Fourth embodiment)
Next, a fourth embodiment of the present invention will be described. FIG. 16 is a schematic configuration diagram of a power generation device according to the fourth embodiment, and FIG. 17 is an enlarged cross-sectional view of a power generation unit. In the following description, the same configurations and methods as those in the first embodiment described above are denoted by the same reference numerals, and description thereof is omitted.
The power generation apparatus 300 of this embodiment is different from the first embodiment described above in that a cylindrical tube cell is used for the power generation unit 354. As shown in FIGS. 16 and 17, the power generation unit 354 has a double pipe structure arranged in the heating furnace 11 in a state where the axial direction thereof matches the length direction of the heating furnace 11. Specifically, as shown in FIG. 17, the solid electrolyte membrane 301, the fuel electrode 302 formed over the entire inner surface of the solid electrolyte membrane 301, and the entire outer surface of the solid electrolyte membrane 301 are formed. The air electrode 304 is provided, and an outer cylindrical portion 305 provided so as to cover the outer side in the radial direction with a gap on the outer side in the radial direction of the air electrode 304. That is, a power generation body 306 is configured in which a fuel electrode 302 is laminated on the inner periphery of the solid electrolyte membrane 301 and an air electrode 304 is stacked on the outer periphery of the entire periphery. Then, oxygen ions generated at the air electrode 304 pass through the solid electrolyte membrane 301 and reach the fuel electrode 302.

  In this case, the inner space of the outer cylindrical portion 305 constitutes a first reaction chamber 310 that causes the oxidant gas to react in the air electrode 304, and the inner space constitutes a second reaction chamber 311 that causes the fuel gas to react in the fuel electrode 302. doing. Further, an injector 55 for spraying liquid fuel toward the second reaction chamber 311 is connected to one end side of the second reaction chamber 311. That is, one end side of the power generation unit 354 protrudes from the end surface on one end side in the longitudinal direction of the heating furnace 11, and the length direction of the power generation unit 354 extends from one end side to the other end side of the power generation unit 354. A temperature gradient is formed so as to gradually increase in temperature.

In this case, in the DO mode, liquid fuel is sprayed from the inside of the second reaction chamber 311 by the injector 55 and an oxidant gas is supplied to the first reaction chamber 310. The oxidant gas supplied to the first reaction chamber 310 becomes oxygen ions in the air electrode 304 of the first reaction chamber 310 by a catalytic reaction. On the other hand, the liquid fuel supplied to the second reaction chamber 311 is converted into fuel gas from the liquid column state through the droplet state by the temperature gradient formed along the length direction of the power generation unit 354. Then, oxygen ions generated at the air electrode 304 pass through the solid electrolyte membrane 301 and move to the fuel electrode 302. As a result, when oxygen ions react with the fuel gas at the fuel electrode 302, power is generated by releasing electrons.
On the other hand, in the DC mode, when carbon deposits due to carbonization of unreacted fuel gas or the like in the second reaction chamber 311 as in the first embodiment described above, the fuel side valve 27 is closed and the second reaction chamber 311 is closed. 2 The inside of the reaction chamber 311 is sealed. Thereby, power generation can be performed when the carbon deposited in the second reaction chamber 311 is oxidized.

Here, FIG. 18 shows the fuel concentration in the second reaction chamber 311 and the temperature in the power generation unit 354 with respect to the position in the length direction of the power generation unit 354 when gas fuel is supplied to the power generation unit 354 of this embodiment. FIG. 19 is a graph showing the electrical conversion efficiency and the output with respect to the position of the power generation unit 354 in the length direction.
As shown in FIG. 18, when gas fuel is supplied as fuel to the power generation unit 354, power generation is performed as needed from one end side of the power generation unit 354, and while the fuel concentration decreases from one end side to the other end side, Thus, it can be seen that the temperature in the power generation unit 354 is rising. Moreover, as shown in FIG. 19, it turns out that the electric power generation output is falling gradually from the one end side of the electric power generation part 354 to the other end side. When the gas fuel is used, the fuel is used for power generation, so that the fuel is diluted from one end side to the other end side of the power generation unit 354, which is considered to lead to a decrease in output.

On the other hand, in this embodiment, since liquid fuel is used as the fuel, adjustment of parameters such as spray pressure and spray time by the injector 55 enables adjustment of the liquid column section, droplet section, and gasification section. It can be performed. That is, by changing the gasification timing (gasification section) for each spray, a space in which the fuel concentration, temperature, output, and the like are uniform over the length direction of the power generation unit 354 can be maintained.
Also in the present embodiment, as in the first embodiment described above, the flow rate of the fuel gas increases as compared with the liquid fuel due to the pressure expansion during the vaporization of the liquid fuel. Therefore, there is no need to use a pump or the like for sending the fuel gas to the fuel electrode 302, so that the manufacturing cost and maintenance load can be reduced, and the apparatus can be reduced in size and weight. And even if it has a long power generation unit 354 in the axial direction like a tube cell, the fuel gas can reach the other end side of the power generation unit 354 and can be uniformly distributed over the entire surface of the power generation unit 354. Fuel gas can be supplied.

FIG. 20 is a graph showing the fuel concentration in the second reaction chamber 311 and the temperature in the power generation unit 354 with respect to the position in the length direction of the power generation unit 354 when liquid fuel is supplied to the power generation unit 354 of this embodiment. FIG. 21 is a graph showing the electrical conversion efficiency and output with respect to the position of the power generation unit 354 in the length direction. 20 and 21 show a case where liquid fuel is sprayed using two types of spray patterns with different gasification sections.
As shown in FIG. 20, when liquid fuel is supplied to the power generation unit 354 as fuel, it can be seen that the fuel concentration rapidly increases at the J point and the K point. That is, the liquid fuel sprayed in two types of spray patterns is converted into fuel gas at two points, J point and K point. Therefore, the output in the length direction of the power generation unit 354 is uniform over the length direction of the power generation unit 354 compared to the case where gas fuel is used. Specifically, the fuel gas converted into fuel gas at point J is used for power generation until reaching point K, but fuel gas converted into fuel gas is supplied again at point K. Power generation is efficiently performed until the other end of the power generation unit 354 is reached. In addition, since the heat of vaporization is necessary to re-gasify the fuel at the point K, the inside of the power generation unit 354 is cooled at this time. As a result, the temperature in the power generation unit 354 is also maintained substantially uniform over the length direction. Furthermore, as shown in FIG. 21, since the fuel concentration in the power generation unit 354 is kept uniform as described above, the output in the length direction of the power generation unit 354 is more uniform than when gas fuel is used. .

According to this structure, even if it is a case where a tube cell is used for the electric power generation part 354, there can exist an effect similar to 1st Embodiment. Further, as described above, by supplying the liquid fuel into the power generation unit 354 by the injector 55, power generation is performed substantially uniformly over the length direction of the power generation unit 354. As a result, the power generation efficiency can be improved and the power generation body 306 can be prevented from being locally degraded. In addition, since the strength is higher than that of the disk-shaped SOFC, cracking of the power generation unit 354 and the like can be prevented even when a thermal shock occurs due to rapid temperature increase / decrease.
In this embodiment, the SOFC solid electrolyte membrane 301 is formed over the entire surface of the tube cell. However, the present invention is not limited to this, and the solid electrolyte membrane 301 is divided along the circumferential direction, Or may be connected in series.

It should be noted that the technical scope of the present invention is not limited to the above-described embodiments, and includes those in which various modifications are made to the above-described embodiments without departing from the spirit of the present invention. In other words, the configuration described in the above-described embodiment is merely an example, and can be changed as appropriate.
In the first embodiment, the switching timing between the DO mode and the DC mode, that is, the case where the amount of carbon deposition is determined based on the voltage has been described. However, the present invention is not limited to this, and the temperature in the second reaction chamber 22 and the like. It is also possible to make a determination based on the point in time when the equilibrium state is no longer maintained from the state of thermal independence.
Furthermore, it is also possible to supply gas fuel directly to the second reaction chamber and generate power with the above-described power generation apparatus.
In each embodiment, both continuous spraying and pulse spraying of liquid fuel are possible.

DESCRIPTION OF SYMBOLS 1,100,200,300 ... Electric power generation apparatus 7,302 ... Fuel electrode (the other electrode) 8,304 ... Air electrode (one electrode) 11 ... Heating furnace 10,306 ... Electric power generation body 22,222 ... Second reaction chamber 42,242 ... first reaction chamber 55 ... injector

Claims (5)

A first reaction chamber for supplying an oxidant gas to one electrode of the power generator of the solid oxide fuel cell, and causing the oxidant gas to react at the one electrode;
A second reaction chamber for supplying a fuel gas to the other electrode of the power generation body and reacting the fuel gas at the other electrode;
The first reaction chamber and the second reaction chamber are provided in a temperature-controllable heating furnace, and a power generator that generates electric power when the oxidant gas and the fuel gas react with each other in the power generator,
The second reaction chamber, connects the injector for injecting liquids fuel toward the other electrode,
A power generation apparatus, wherein a gasification section in which the liquid fuel injected from the injector is gasified by controlling the temperature of the heating furnace is set in the second reaction chamber.   The power generator according to claim 1, wherein the injector performs pulse injection of the liquid fuel. The fuel gas is a dry hydrocarbon fuel containing no water vapor,
3. The power generator according to claim 1, further comprising: a fuel gas consumption mode in which power generation is performed by reacting the fuel gas with a component other than solid carbon as a fuel source and the oxidant gas. 4. . The fuel gas is a fuel gas containing solid carbon,
A precipitated carbon consumption mode in which the temperature of the heating furnace is controlled to a predetermined temperature in a state where the second reaction chamber is closed in order to consume solid carbon precipitated in the second reaction chamber as a fuel source by carbonization of the fuel gas. The power generation device according to claim 1, further comprising: The fuel gas is a fuel gas containing solid carbon,
Carbon deposition judgment means for judging whether or not solid carbon is deposited in the second reaction chamber by a carbonization of the fuel gas in a predetermined value or more;
Based on the determination result of the carbon deposition determination means, comprising a control unit that performs switching control of the power generation mode,
The controller is
A fuel gas consumption mode in which power generation is performed using a component other than solid carbon as a fuel source in the fuel gas when the carbon deposition determination means determines that the amount of solid carbon deposited is less than a predetermined value;
2. The precipitated carbon consumption mode in which power generation is performed using solid carbon deposited in the second reaction chamber as a fuel source when the amount of solid carbon deposited is determined to be equal to or greater than a predetermined value. Item 3. The power generation device according to Item 2.

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