JP7181065B2 - Reactor and fuel cell power generation system - Google Patents

Description

The present invention relates to a reactor and a fuel cell power generation system that includes the reactor and uses a carbon compound fuel to generate power.

When carbon compound fuel is used in the fuel cell power generation system, the exhaust gas discharged from the fuel cell contains carbon dioxide gas. Separation of carbon dioxide gas from this exhaust gas has been considered (for example, see Patent Documents 1 to 5).

Japanese Patent No. 5581240 JP 2013-196890 A Japanese Patent No. 54137199 JP 2012-164423 A Japanese Patent No. 3334567

By liquefying carbon dioxide gas into liquefied carbon dioxide, it becomes easier to transport, fix by injection into reservoirs, and use in commerce and industry.
Since exhaust gas contains gases (impurities) other than carbon dioxide gas, it is necessary to remove gases other than carbon dioxide gas in order to obtain liquefied carbon dioxide with less impurities. Although there are apparatuses for obtaining high-concentration carbon dioxide gas by reacting unburned components of exhaust gas with oxygen, it is desired to accelerate the reaction when obtaining carbon dioxide gas.

It is also known to produce and store carbon from the separated carbon dioxide gas so as not to release the carbon dioxide gas into the atmosphere. BACKGROUND ART There is known a carbon production apparatus that produces carbon by reacting carbon dioxide gas and hydrogen in the presence of a catalyst (reduction reaction) (see, for example, Patent Document 5). The reduction reaction requires a high temperature, and in order to initiate the reduction reaction, for example, it is necessary to burn hydrogen and rapidly heat the carbon dioxide gas, the hydrogen, and the catalyst with the heat of the combustion gas.
As described above, various reactions take place in the fuel cell power generation system, and it is desired to accelerate the reactions.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a reactor capable of accelerating the reaction, and a fuel cell power generation system equipped with the reactor.

The reaction device according to the first aspect has a cylindrical shape, and includes a partition wall that separates the inner first flow channel and the outer second flow channel, and at least one of the first flow channel and the second flow channel. and a catalyst provided in at least one of the first flow path and the second flow path, the flow path being formed linearly in the direction of the cylinder axis. and a partition member formed in a spiral shape in the direction of the cylinder axis so that the channel length from one end to the other end in the cylinder axis direction is relatively long .

In the reactor according to the first aspect , one or more types of gas can be flowed through the first flow path, and one or more types of gas can be flowed through the second flow path. The same gas or different gases can be flowed in the first channel and the second channel.
In addition, different types of gases can be reacted with each other in the spirally formed first channel or second channel.

At least one of the first flow path and the second flow path can be formed in a spiral shape in the direction of the cylinder axis. A first form in which the second flow path is helical in the direction of the cylinder axis, and a second form in which the first flow path is helical in the direction of the cylinder axis and the second flow path is linear in the direction of the cylinder axis. There are a second form and a third form in which the first flow path is helical in the direction of the cylinder axis and the second flow path is also helical in the direction of the cylinder axis.

The channel formed spirally in the direction of the cylinder axis can have a longer channel length from one end to the other end than the channel formed linearly in the direction of the cylinder axis. It is possible to lengthen the time for the gases to react with each other, the residence time of the gases, and the residence time of the reactant generated by the reaction of the gases in the channel.

For example, one of the first flow path and the second flow path is formed in a spiral shape, two gases of different types are introduced from one end of the spiral flow path, and heat is generated by one gas and the other gas. The reactants produced by the reaction flow over time in a long flow path, and the heat produced by the exothermic reaction is transferred over a long period of time (versus a straight flow path) to the adjacent first or second flow path. The other of the paths can be fully applied.
In addition, since the heat generated in one of the first flow path and the second flow path can be sufficiently applied to the other of the adjacent first flow path and the second flow path, An endothermic reaction between different gases can also be reliably generated in the other channel of the second channel.

In addition, two gases of different types can be introduced from one end of the helical channel, and one gas and the other can be reacted for a long time in the long channel.

A second aspect is the reactor according to the first aspect , wherein the partition includes a gas-permeable membrane that allows a gas to be reacted to permeate from one of the first channel and the second channel to the other. .

In the reactor according to the second aspect , the partition separating the first channel and the second channel has a gas permeable part that allows the gas to be subjected to the reaction to permeate from one of the first channel and the second channel to the other. Since the membrane is provided, the gas in the first channel is allowed to permeate the gas permeable membrane and flow into the second channel, and the gas in the second channel is allowed to permeate the gas permeable membrane and flow into the first channel. can be made
Therefore, the gas in the first channel and the gas in the second channel can be caused to react in the first channel or the second channel. Also, the reaction between gases can be accelerated by a catalyst.

A third aspect is the reactor according to the second aspect , wherein the catalyst is laminated on the gas permeable side of the gas permeable membrane.

In the reactor according to the third aspect , the catalyst is provided on the gas permeable side of the gas permeable membrane, so that the reaction between the gases can be promoted in the channel on the gas permeable side.

In addition, if the channel for causing the reaction between the gases is formed in a spiral shape, it is possible to take a longer reaction time in the spiral channel.

A fuel cell power generation system according to a fourth aspect generates power using a fuel gas containing a carbon compound and supplied to the fuel electrode and an oxidant gas containing oxygen and supplied to the air electrode, and unreacted gas from the fuel electrode. a fuel cell in which a fuel electrode off-gas containing the fuel gas and a first carbon dioxide gas is discharged, and an air electrode off-gas containing oxygen is discharged from the air electrode; is a reaction channel provided with an oxidation catalyst as the catalyst and the partition member, the gas permeable membrane is an oxygen permeable membrane, and the other of the first channel and the second channel is an air electrode The reactor according to the third aspect having an offgas passage, a first introduction passage for introducing the fuel electrode offgas into the reaction passage, and a second introduction for introducing the air electrode offgas into the air electrode offgas passage. and a second carbon dioxide is generated in the reaction path by an oxidation reaction between the carbon compound in the fuel electrode offgas and the oxygen that has permeated the oxygen permeable membrane from the first flow path. .

In the fuel cell power generation system according to the fourth aspect , a fuel gas containing a carbon compound is supplied to the fuel electrode of the fuel cell, and an oxidant gas containing oxygen is supplied to the air electrode, whereby the fuel cell generates power, A fuel electrode off-gas containing unreacted fuel gas and first carbon dioxide gas is discharged from the fuel electrode, and an air electrode off-gas containing oxygen is discharged from the air electrode.

In the reactor, for example, the fuel electrode off-gas is introduced through the first introduction passage into the first passage as the reaction passage, and the air electrode off-gas is introduced through the second introduction passage into the second passage as the air electrode off-gas passage. When introduced into the channel, in the first channel, the oxidation catalyst accelerates the oxidation reaction between the oxygen permeated through the gas permeable membrane and the unreacted carbon compound of the fuel gas to produce the second carbon dioxide gas. generated. Thereby, the first channel can discharge the first carbon dioxide gas contained in the fuel electrode off-gas and the second carbon dioxide gas generated by the oxidation reaction.
Further, by forming the first channel in a spiral shape, it is possible to take a longer oxidation reaction time in the channel. Thereby, high-concentration carbon dioxide gas can be obtained.
Note that the second flow path may be formed in a spiral like the first flow path.

A fuel cell power generation system according to a fifth aspect generates power using a fuel gas containing a carbon compound and supplied to a fuel electrode, and an oxidant gas containing oxygen and supplied to an air electrode, and carbon dioxide is generated from the fuel electrode. A fuel cell for discharging a gas and for discharging an oxygen-containing air electrode off-gas from the air electrode; a water electrolyzer for electrolyzing water to generate hydrogen gas and oxygen gas; and an inner second flow path arranged across a partition wall, and the inside of the flow path is formed in a straight line in the direction of the cylinder axis in the first flow path. Then, a spiral partition member is formed in the direction of the cylinder axis so that the channel length from one end to the other end in the cylinder axis direction becomes long. a reaction device in which the carbon dioxide gas and the hydrogen gas are supplied to the second flow path, and the carbon dioxide gas and the hydrogen gas are supplied from the second flow path, and the and a carbon deposition part where carbon is generated from carbon dioxide gas.

In the fuel cell power generation system according to the fifth aspect , a fuel gas containing a carbon compound is supplied to the fuel electrode of the fuel cell, and an oxidant gas containing oxygen is supplied to the air electrode, whereby the fuel cell generates power, Carbon dioxide gas is discharged from the fuel electrode, and air electrode off-gas containing oxygen is discharged from the air electrode.

A water electrolyzer electrolyzes water to produce hydrogen gas and oxygen gas.

In the reaction device, the hydrogen gas and the oxygen gas supplied from the water electrolysis device can be supplied to the spiral first channel to cause combustion reaction. A combustion reaction between hydrogen and oxygen generates high-temperature steam, and the heat of the steam is transferred to the second channel through the partition wall. The carbon dioxide gas supplied from the fuel cell and the hydrogen gas supplied from the water electrolysis device are mixed inside the second channel to form a mixed gas, which is heated by the heat generated by the combustion reaction.

Here, since the high-temperature water vapor passes through the spirally formed first channel having a long passage length and is discharged from the other end side, it takes time until the water vapor is discharged from the other end side. As a result, the heat of the steam can be sufficiently transferred to the other side of the second flow path over time. This makes it possible to reliably heat the mixed gas containing carbon dioxide gas and hydrogen gas in the second channel.

The heated mixed gas is supplied to the carbon deposition section on the downstream side, where carbon is generated from the carbon dioxide gas.

According to the reaction device and the fuel cell power generation system according to the present invention, the reaction can be efficiently caused.

1 is a schematic diagram of a fuel cell power generation system according to a first embodiment; FIG. FIG. 3 is a cross-sectional view along the axis showing the combustor with an oxygen permeable membrane; It is a state diagram of carbon dioxide. FIG. 2 is a schematic diagram of a fuel cell power generation system according to a second embodiment; FIG. 6 is a configuration diagram showing a powdered carbon generator of a fuel cell power generation system according to a second embodiment;

[First embodiment]
An example of an embodiment of the present invention will be described in detail below with reference to the drawings.
FIG. 1 shows a fuel cell power generation system 10A according to a first embodiment of the invention. The fuel cell power generation system 10A mainly includes a first fuel cell stack 12, a second fuel cell stack 14, a combustor 20 with an oxygen permeable membrane as a reactor, a condenser 26, and a second heat exchanger 32. , exhaust heat input type absorption chiller 36, water tank 27, carbon dioxide gas liquefying unit 66, tank 84, etc., which are provided on-site. The fuel cell power generation system 10A also includes a control section (not shown).

As shown in FIG. 1, the first fuel cell stack 12 is a proton-conducting solid oxide fuel cell (PCFC: Proton Ceramic Solid Oxide Fuel Cell), and includes an electrolyte layer 12C and a surface of the electrolyte layer 12C. It has the 1st fuel electrode (fuel electrode) 12A and the 1st air electrode (air electrode) 12B each laminated|stacked on the back surface.

The basic configuration of the second fuel cell stack 14 is the same as that of the first fuel cell stack 12, with a second fuel electrode 14A corresponding to the first fuel electrode 12A and a second fuel electrode 14A corresponding to the first air electrode 12B. It has two air electrodes 14B and an electrolyte layer 14C corresponding to the electrolyte layer 12C.

One end of the reformed gas pipe P1-2 is connected to the first fuel electrode 12A of the first fuel cell stack 12, and the other end of the fuel gas pipe P1-1 is connected to a reformer 54, which will be described later. ing. Fuel gas is sent from the reformer 54 to the first fuel electrode 12A. In this embodiment, methane is used as the fuel gas, but any gas capable of generating hydrogen by reforming is not particularly limited, and a hydrocarbon fuel can be used. Examples of hydrocarbon fuels include natural gas, LP gas (liquefied petroleum gas), biogas, coal gasification gas, and lower hydrocarbon gas. Examples of the lower hydrocarbon gas include lower hydrocarbons having 4 or less carbon atoms such as methane, ethane, ethylene, propane and butane, and methane used in the present embodiment is preferred. The hydrocarbon fuel may be a mixture of the above-mentioned lower hydrocarbon gases, and the above-mentioned lower hydrocarbon gases may be gases such as natural gas, city gas, and LP gas. If the raw material gas contains impurities, a desulfurizer or the like is required, but it is omitted in FIG.

A water vapor pipe P2 is connected to the reformed gas pipe P1-2, and water vapor is appropriately supplied from a water vapor source (not shown) at the time of starting or stopping. Methane and water vapor are combined in the fuel gas pipe P1 and supplied to the first fuel electrode 12A. The steam from the steam pipe P2 is supplementarily supplied when necessary during the starting and stopping processes of the fuel cell power generation system 10A.

At the first fuel electrode 12A, the fuel gas is steam-reformed to produce hydrogen and carbon monoxide as shown in the following equation (1). Further, as shown in the following formula (2), carbon monoxide and water vapor are shifted to generate carbon dioxide and hydrogen.

CH ₄ +H ₂ O→3H ₂ +CO (1)
CO+ _H2O → _CO2 + _H2 (2)

Then, in the first fuel electrode 12A, hydrogen is separated into hydrogen ions and electrons as shown in the following formula (3).

(Anode reaction)
H ₂ →2H ⁺ +2e ⁻ (3)

The hydrogen ions move through the electrolyte layer 12C to the first air electrode 12B. The electrons travel through an external circuit (not shown) to the first cathode. As a result, power is generated in the first fuel cell stack 12 . During power generation, the first fuel cell stack 12 generates heat.

An oxidant gas (air) is supplied to the first air electrode 12B of the first fuel cell stack 12 from an oxidant gas pipe P5. Air is introduced into the oxidant gas pipe P5 by the oxidant gas blower B2. The oxidant gas pipe P5 is provided with a second heat exchanger 32, and the air flowing through the oxidant gas pipe P5 is heated by heat exchange with the cathode offgas flowing through the cathode offgas pipe P6, which will be described later. The heated air is supplied to the first air electrode 12B.

In the first air electrode 12B, as shown in the following equation (4), hydrogen ions that have migrated from the first fuel electrode 12A through the electrolyte layer 12C and electrons that have migrated from the first fuel electrode 12A through the external circuit are , reacts with oxygen in the oxidant gas to produce water vapor.

(air electrode reaction)
2H ⁺ +2e ⁻ +1/2O ₂ →H ₂ O (4)

An air electrode offgas pipe P6 is connected to the first air electrode 12B. The cathode off-gas is discharged from the first cathode 12B to the cathode off-gas pipe P6. The oxidant gas pipe P5 and the air electrode off-gas pipe P6 are also connected to the second air electrode 14B in the same manner, and the first air electrode 12B and the second air electrode 14B are connected in parallel.

One end of the first fuel electrode off-gas pipe P7 is connected to the first fuel electrode 12A of the first fuel cell stack 12, and the other end of the first fuel electrode off-gas pipe P7 is connected to the second fuel cell stack 14 of the second fuel cell stack 14. 2 is connected to the fuel electrode 14A. The first fuel electrode off-gas is delivered from the first fuel electrode 12A to the first fuel electrode off-gas pipe P7. The fuel electrode off-gas contains unreformed fuel gas components, unreacted hydrogen, unreacted carbon monoxide, carbon dioxide, water vapor, and the like.

One end of a second fuel electrode off-gas pipe P7-2 is connected to the second fuel electrode 14A of the second fuel cell stack 14, and the second fuel electrode off-gas is delivered from the second fuel electrode 14A. The other end of the second anode offgas pipe P7-2 is connected to the combustor 20 with an oxygen permeable membrane.

In the second fuel cell stack 14, a power generation reaction similar to that in the first fuel cell stack 12 occurs, and the cathode offgas is sent from the second cathode 14B to the cathode offgas pipe P6. The air electrode off-gas pipe P6 connected to the second air electrode 14B is branched upstream of the junction with the air electrode off-gas pipe P6 connected to the first air electrode 12B. -2 is formed. The branch air electrode offgas pipe P6-2 is provided with a flow control valve 42 capable of flow control. The flow control valve 42 is connected with the control section. The flow control valve 42 is controlled by the controller to adjust the flow rate of the cathode offgas branched to the branched cathode offgas pipe P6-2. The downstream end of the branched cathode offgas pipe P6-2 is connected to the combustor 20 with an oxygen permeable membrane.

(Combustor with oxygen permeable membrane)
As shown in FIG. 2, the combustor 20 with an oxygen permeable membrane includes an outer cylinder 20A, a cylindrical gas permeable membrane 23 disposed inside the outer cylinder 20A, and an outer cylinder 20A and the cylindrical gas permeable membrane 23. The inside of the cylinder is sealed and has a multiple cylindrical shape including a closing member 20B for closing the opening on the axial end side of the cylinder.

An annular combustion section 22 is provided between the outer cylinder 20A and the gas permeable membrane 23, and an oxygen separation section 24 is provided on the inner peripheral side of the cylindrical gas permeable membrane 23. The combustion section 22 and the oxygen separation section 24 are separated. are separated by a gas permeable membrane 23 as a partition.

The combustion portion 22 is provided with an outer spiral passage forming member 28 having a spiral shape inside, and has a combustion space 22A as a first flow path of the present invention, which is spiral in the direction of the cylinder axis of the outer cylinder 20A. formed.
The outer spiral passage forming member 28 is, for example, a belt-shaped member formed in a spiral shape, and has an inner peripheral edge fixed to the outer peripheral surface of the gas permeable membrane 23 and an outer peripheral edge fixed to the inner peripheral surface of the outer cylinder 20A. ing.

The oxygen separation section 24 is provided with an inner spiral passage forming member 29 having a spiral shape inside, and is an air passage serving as the second passage of the present invention, which is spiral in the axial direction of the outer cylinder 20A. 24A is formed.
The inner spiral passage forming member 29 is, for example, a belt-shaped member formed in a spiral shape, and the outer peripheral edge is fixed to the inner peripheral surface of the gas permeable membrane 23 . Note that the inner spiral passage forming member 29 may have a spiral staircase shape in which the inner peripheral edge is fixed to the outer peripheral surface of a shaft (not shown) provided in the shaft core portion.

A so-called high-temperature oxygen-permeable film is used as the gas-permeable film 23, and a mixed conductive ceramic dense film of electrons and oxygen ions (electroconductive can be used, and other materials than LSCF can also be used.

An oxidation catalyst film 23A is laminated on the combustion space 22A side of the gas permeable film 23 . The oxidation catalyst film 23A is, for example, a porous body formed in the form of a catalyst film made of a material such as nickel or ruthenium.

As shown in FIGS. 1 and 2, the other end of the second anode offgas pipe P7-2 is connected to the inlet of the combustion space 22A, and the branched cathode offgas pipe P6 is connected to the inlet of the air flow path 24A. -2 downstream ends are connected.

The second cathode off-gas is supplied to the air flow path 24A, and oxygen contained in the second cathode off-gas permeates the gas permeable membrane 23 and moves to the combustion space 22A. The second cathode off-gas that does not move to the combustion space 22A is exhausted to the outside from an exhaust pipe P12 connected to the outlet side of the air flow path 24A.

The second fuel electrode off-gas is supplied to the combustion space 22A and mixed with oxygen that has moved from the oxygen separator 24 through the gas permeable membrane 23 . As a result, a combustion reaction occurs between combustible gas components (unreformed methane, unreacted hydrogen, unreacted carbon monoxide, etc.) in the second fuel electrode offgas and oxygen through the oxidation catalyst, resulting in carbon dioxide and steam is produced. A combustion off-gas pipe P8-1 is connected to the outlet side of the combustion space 22A, and combustion off-gas is delivered from the combustion space 22A.

As shown in FIG. 1, the combustion off-gas pipe P8-1 is connected to an inner flow path 55B of the reformer 54, which will be described later.

(reformer)
The reformer 54 of this embodiment has a multi-cylindrical shape, and includes an annular vaporization passage 55A arranged radially outward, and an inner passage radially arranged adjacent to the vaporization passage 55A. 55B. A partition wall 57 separates the vaporization channel 55A and the inner channel 55B.

The vaporization flow path 55A has an upper annular space filled with a reforming catalyst 58, and a lower side is a spiral flow path 55A-2 that is spirally formed in the axial direction of a cylindrical cylinder.
One end of the fuel gas pipe P1-1 and one end of the water supply pipe P2-2 are connected to the lower end (upstream side of the flow channel) of the vaporization flow channel 55A.
A fuel supply blower B1 is connected to the other end of the fuel gas pipe P1-1, and methane from the fuel gas source is supplied to the vaporization flow path 55A of the reformer 54 by the fuel supply blower B1.
The other end of the water supply pipe P2-2 is connected to the water tank 27. As shown in FIG. The water supply pipe P2-2 is provided with an ion exchange resin 56 and a pump 27B. The water stored in the water tank 27 is supplied to the reformer 54 through the ion exchange resin 56 by driving the pump 27B.

One end of a reformed gas pipe P1-2 is connected to the upper end (downstream side of the flow path) of the vaporization flow path 55A. The other end of the reformed gas pipe P1-2 is connected to the first fuel electrode 12A of the first fuel cell stack 12. As shown in FIG.

One end of the combustion off-gas pipe P8-1 is connected to the upper end of the inner flow passage 55B (on the upstream side of the flow passage), and the other end of the combustion off-gas pipe P8-1 is connected to the combustion space of the combustor 20 with an oxygen permeable membrane. 22A. The high-temperature combustion off-gas delivered from the combustion space 22A is supplied to the inner flow path 55B through the combustion off-gas pipe P8-1.

One end of the combustion off-gas pipe P8-2 is connected to the lower end (downstream side of the flow passage) of the inner flow passage 55B, and the other end of the combustion off-gas pipe P8-2 is connected to the condenser 26, which will be described later. The combustion off-gas discharged from the inner flow path 55B is sent to the later-described condenser 26 through the combustion off-gas pipe P8-2.

Since high-temperature combustion off-gas passes through the inner flow path 55B, the partition 57 separating the vaporization flow path 55A and the inner flow path 55B is heated by the combustion off-gas. Therefore, in the vaporization channel 55A adjacent to the inner channel 55B, the reforming catalyst 58, the fuel gas, and the water are heated by the heat of the combustion off-gas, the fuel gas is steam-reformed, and the steam-reformed fuel gas is is delivered to the first fuel electrode 12A of the first fuel cell stack 12 through the reformed gas pipe P1-2.

(Condenser)
A cooling water circulation flow path 26A is connected to the condenser 26, and cooling water from an exhaust heat input type absorption chiller 36, which will be described later, is circulated and supplied by driving a pump 26P, and sent out from the reformer 54. Combustion off-gas is cooled. This causes water vapor in the combustion off-gas to condense. The condensed water is delivered to the water tank 27 through the water pipe P9.

The combustion off-gas from which water vapor has been separated and removed is sent to the carbon dioxide gas pipe P10. The combustion off-gas from which water (liquid phase) has been removed by the condenser 26 is a gas with a high carbon dioxide concentration, and the combustion off-gas is referred to as a carbon dioxide-rich gas. A composition detector 44 is provided in the carbon dioxide gas pipe P10. The composition detector 44 detects the composition of the carbon dioxide-rich gas delivered from the condenser 26 . Specifically, the concentration of any one or more of combustible gases such as methane, carbon monoxide, and hydrogen, carbon dioxide, and oxygen is detected. The composition detection unit 44 is connected to the control unit, and transmits the detected composition information of the carbon dioxide-rich gas to the control unit. Note that the control unit performs various controls to increase the concentration of carbon dioxide gas.

A carbon dioxide gas liquefying unit 66, which will be described later, is provided on the downstream side of the carbon dioxide gas pipe P10.

A second heat exchanger 32 is provided downstream of the junction where the air electrode offgas pipes P6 from the first air electrode 12B and the second air electrode 14B are merged. In the second heat exchanger 32, heat is exchanged between the cathode offgas flowing through the cathode offgas pipe P6 and the oxidizing gas flowing through the oxidizing gas pipe P5, the oxidizing gas is heated, and the cathode offgas is converted into Cooled. The cathode off-gas passes through the second heat exchanger 32 and is supplied to the exhaust heat input type absorption chiller 36 .

(exhaust heat input type absorption chiller)
The exhaust heat input type absorption chiller 36 is a heat pump that uses exhaust heat to generate cold heat, and as an example, a steam/exhaust heat input type absorption chiller can be used. In a steam/exhaust heat input type absorption chiller, water is separated from the absorbent by heating the absorbent (for example, lithium bromide aqueous solution or ammonia aqueous solution) that has absorbed water vapor with the heat of the air electrode off-gas. do. Water vapor is condensed in the air electrode off-gas obtained by heating and cooling the absorbing liquid, and the condensed water is supplied to the water tank 27 through the water pipe P36-2. After the water vapor is condensed and removed, the air electrode off-gas is sent to the exhaust pipe P36-1 and exhausted to the outside of the exhaust heat input type absorption chiller .

A pump for circulating the absorbing liquid and a pump for circulating water separated from the absorbing liquid (both not shown) are provided inside the exhaust heat input type absorption chiller 36 . These pumps are driven by DC motors, which can be driven by DC power generated by the first fuel cell stack 12 and the second fuel cell stack 14 .

The absorbent regenerated by heating promotes the evaporation of water by absorbing water vapor and contributes to the generation of cold energy. The exhaust heat input type absorption chiller 36 is connected to a cooling tower 38 via a heat dissipation circuit 37 . A pump 37P is installed in the heat radiation circuit 37, and cooling water is supplied to the heat radiation circuit 37 by the pump 37P. Absorption heat generated when the absorption liquid absorbs water vapor in the exhaust heat input type absorption chiller 36 is released to the atmosphere from the cooling tower 38 via the cooling water flowing through the radiation circuit 37 .

Cold heat generated by the exhaust heat input type absorption chiller 36 is sent to the condenser 26 via the cooling water flowing through the cooling water circulation flow path 26A, where the combustion off-gas is cooled in the condenser 26, and the combustion off-gas is cooled. Water vapor is condensed out.

The water tank 27 is connected to a cooling water circulation channel 26A, a heat dissipation circuit 37, and a heat medium channel (not shown) through which water flows as a heat medium for the absorption chiller 36 with waste heat input. In the cooling water circulation flow path 26A, the heat dissipation circuit 37, and the heat medium flow path, water is appropriately replenished from the water tank 27 through the replenishment system 67 described below when the water is insufficient.
Note that the exhaust heat input type absorption chiller 36 has, as an example, the ability to generate cooling water at -5°C to 12°C.

(replenishment system)
The water tank 27 is connected to a replenishment system 67 including a pipe P11, a pump 27A, and the like. One end of the pipe P11 is connected to the water tank 27, and the other end of the pipe P11 is branched into three and connected to the cooling tower 38, the cooling water circulation passage 26A, and the liquefaction cooling water circulation passage 70A, which will be described later. ing. The pump 27A is provided in the pipe P11 before branching, and an electromagnetic valve (not shown) is attached to each of the three branched pipes. In addition, the pump 27A and the electromagnetic valve are controlled by a control section which will be described later.

The cooling tower 38, the cooling water circulation passage 26A, and the liquefaction cooling water circulation passage 70A are each provided with a buffer tank (not shown) for storing cooling water. A liquid level sensor (not shown) is provided to detect the This liquid level sensor is connected to a control section, which will be described later, and outputs detection data of the liquid level (reserved amount of cooling water) to the control section. Thereby, the controller can grasp the amount of cooling water stored in each of the cooling tower 38, the cooling water circulation passage 26A, and the cooling water circulation passage 70A for liquefaction.

(Carbon dioxide gas liquefaction part)
The carbon dioxide-rich gas sent to the carbon dioxide gas pipe P10 is sent to the carbon dioxide gas liquefying section 66 that includes a compressor 68, a cooling device 70, and the like.
The carbon dioxide-rich gas sent to the carbon dioxide gas liquefying section 66 is first compressed by the compressor 68 . The compressor 68 is driven by a DC motor (not shown) and is capable of compressing the carbon dioxide gas to 4 MPa or higher. In addition, the DC motor of the compressor 68 is driven by the electric power obtained from the first fuel cell stack 12 and the second fuel cell stack 14. For example, when the system is started, an external commercial power source is used. or by power (surplus power) obtained from renewable energy power generation (not shown). Examples of renewable energy power generation include photovoltaic power generation, solar thermal power generation, hydroelectric power generation, wind power generation, geothermal power generation, wave power generation, temperature difference power generation, biomass power generation, and the like. good. Note that the compressor 68 is not limited to being driven by a DC motor, and may be driven by an AC motor.

Since the DC motor of the compressor 68 can be directly driven using the DC power obtained from the first fuel cell stack 12 and the second fuel cell stack 14, for example, the first fuel cell stack 12 and the second fuel cell stack 14 is converted into AC power, and the AC power is used to drive the AC motor. Note that the DC motor of the compressor 68 is controlled by the controller.

The carbon dioxide gas compressed by the compressor 68 is sent to the cooling device 70 via the pipe P114. A temperature sensor 74 and a pressure sensor 76 are provided in the pipe P114, and the temperature data of the carbon dioxide gas measured by the temperature sensor 74 and the pressure data of the carbon dioxide gas measured by the pressure sensor 76 are controlled respectively. sent to the department.

A liquefaction cooling water circulation path 70A is piped to the cooling device 70, and a circulation pump 78 controlled by a control unit is attached to the liquefaction cooling water circulation path 70A. The liquefaction cooling water circulation path 70A is circulated with cooling water from the exhaust heat input type absorption chiller 36, and cools the compressed carbon dioxide-rich gas supplied from the compressor 68 to generate liquefied carbon dioxide.

A temperature sensor 80 that detects the temperature of the cooling water flowing into the cooling device 70 is provided in the liquefaction cooling water circulation path 70A. Cooling water temperature data measured by the temperature sensor 80 is sent to the controller. A flow rate sensor (not shown) for measuring the flow rate of the cooling water may be provided in the liquefaction cooling water circulation path 70A.

The liquefied carbon dioxide generated by the cooling device 70 is sent to the tank 84 via the pipe P115 and the pump 82 and stored therein.

The fuel cell power generation system 10A is provided with a control section (not shown) that controls the entire system. It is composed of a CPU, a ROM, a RAM, a memory, and the like. The memory stores data, procedures, and the like necessary for flow rate adjustment processing, cooling water temperature adjustment processing, and processing during normal operation, which will be described later. The control unit is connected to the flow control valve 42, the composition detection unit 44, the exhaust heat input type absorption chiller 36, and the like. The control unit controls the flow control valve 42, the composition detection unit 44, the exhaust heat input type absorption chiller 36, and the like. Note that the control unit is also connected to devices other than those described above.

In the fuel cell power generation system 10A, pumps, blowers, and other accessories are driven by electric power generated by the fuel cell power generation system 10A. In order to efficiently use the direct current power generated by the fuel cell power generation system 10A without converting it to alternating current, the auxiliary equipment is preferably driven by direct current.

(action, effect)
Next, the operation of the fuel cell power generation system 10A of this embodiment will be described.

In the fuel cell power generation system 10A, the fuel supply blower B1 sends fuel gas (methane) from the fuel gas source to the reformer 54 through the fuel gas pipe P1-1, and the reformer 54 reforms the fuel gas. quality is done.
The reformed fuel gas is supplied to the first fuel electrode 12A of the first fuel cell stack 12 through the fuel gas pipe P1-2.
Steam for steam reforming is supplied from the steam pipe P2 to the first fuel electrode 12A through the fuel gas pipe P1-2.

At the first fuel electrode 12A of the first fuel cell stack 12, the fuel gas is steam reformed to produce hydrogen and carbon monoxide. In addition, carbon monoxide and hydrogen are produced by a shift reaction between the produced carbon monoxide and water vapor.

Air is supplied to the first air electrode 12B of the first fuel cell stack 12 through the oxidant gas pipe P5. In the first fuel cell stack 12, hydrogen ions move in the first fuel electrode 12A and the first air electrode 12B, and the reactions described above occur to generate power. From the first fuel electrode 12A of the first fuel cell stack 12, the first fuel electrode off-gas is sent to the first fuel electrode off-gas pipe P7. Further, from the first air electrode 12B, the air electrode off-gas is sent to the air electrode off-gas pipe P6.

The first fuel electrode off-gas sent out from the first fuel electrode 12A is guided to the first fuel electrode off-gas pipe P7 and supplied to the second fuel electrode 14A of the second fuel cell stack 14 . Air is supplied to the second air electrode 14B of the second fuel cell stack 14 through the oxidant gas pipe P5.
Electric power is generated in the second fuel cell stack 14 in the same manner as in the first fuel cell stack 12 . The second fuel electrode off-gas is delivered from the second fuel electrode 14A of the second fuel cell stack 14 to the second fuel electrode off-gas pipe P7-2. Further, from the second air electrode 14B, the air electrode off-gas is delivered to the air electrode off-gas pipe P6.

The cathode off-gas is supplied to the exhaust heat input type absorption chiller 36 via the second heat exchanger 32 . In the second heat exchanger 32, heat is exchanged between the cathode off-gas and the oxidizing gas, and the oxidizing gas is heated by the cathode off-gas. In the exhaust heat input type absorption chiller 36, as described above, cold heat is generated using the heat of the air electrode off-gas.

The second fuel electrode off-gas is supplied to the combustion section 22 of the combustor 20 with an oxygen permeable membrane and flows through the combustion space 22A.

The cathode offgas branched to the branched cathode offgas pipe P6-2 is supplied to the oxygen separator 24 of the combustor 20 with an oxygen permeable membrane. The air electrode off-gas supplied to the oxygen separation section 24 flows through the air flow path 24A. In the air flow path 24A, oxygen contained in the cathode offgas permeates the gas permeable membrane 23 and moves toward the combustion space 22A. In the combustion space 22A of the combustion section 22, a combustion reaction occurs between combustible gas (methane, hydrogen, carbon monoxide, etc.) in the second fuel electrode offgas and oxygen to produce carbon dioxide and water vapor.

In the combustor 22 of the oxygen permeable membrane combustor 20, the oxidation catalyst promotes the oxidation reaction between the oxygen permeated through the gas permeable membrane 23 and the unreacted combustible gas of the fuel gas to generate carbon dioxide gas. Furthermore, since the combustion space 22A is formed spirally and has a long passage length, it is possible to take a long time for the oxidation reaction, and a sufficient amount of oxygen is supplied from the air passage 24A to the combustion space 22A side. It can be moved to carry out the oxidation reaction sufficiently and efficiently. As a result, combustion off-gas with an increased carbon dioxide gas concentration can be discharged from the combustion section 22 .

Combustion off-gas containing carbon dioxide and water vapor is delivered from combustion space 22A to combustion off-gas pipe P8. The combustion off-gas sent to the combustion off-gas pipe P8 is supplied to the condenser 26 through the inner flow path 55B of the reformer 54. As shown in FIG.

In the reformer 54, in the vaporization passage 55A, the mixed gas of fuel gas and steam and the reforming catalyst 58 are heated by heat exchange with the combustion off-gas, and the steam reforming reaction produces hydrogen and carbon monoxide. be done. In addition, carbon monoxide and hydrogen are produced by a shift reaction between the produced carbon monoxide and water vapor. A reformed gas containing unreacted fuel gas (methane), hydrogen, carbon monoxide and carbon dioxide is supplied to the first fuel electrode 12A through a reformed gas pipe P1-2.

Since the lower side of the vaporization flow path 55A is a long spiral flow path 55A-2 spirally formed in the direction of the cylinder axis of the cylindrical shape, the water supplied together with the fuel gas has a long spiral flow path 55A. It is sufficiently heated to become water vapor while passing through -2 over time. After the heated fuel gas and water vapor flow through the spiral flow path 55A-2, they pass through the reforming catalyst 58 heated by the heat of the combustion off-gas, so that the reforming reaction occurs efficiently and reliably. .

The combustion off-gas supplied to the condenser 26 is cooled by the cooling water from the exhaust heat input type absorption chiller 36 circulated through the cooling water circulation passage 26A, and water vapor in the combustion off-gas is condensed. The condensed water is sent to the water tank 27 through the water pipe P9 and stored in the water tank 27 .

The combustion off-gas from which water vapor has been removed by the condenser 26 becomes carbon dioxide-rich gas having a high carbon dioxide concentration, and is sent to the composition detection unit 44 via the carbon dioxide gas pipe P10. The composition detector 44 detects the composition of the carbon dioxide-rich gas and transmits the detected information to the controller.

Based on the composition information transmitted from the composition detection unit 44, the control unit controls the flow rate adjustment valve 42 to adjust the amount of air electrode offgas branched to the branch air electrode offgas pipe P6-2, and exhaust heat input type The absorption chiller 36 controls the temperature and flow rate of cooling water sent to the cooling water circulation passage 26A and the like.

In the flow rate adjustment process, it is determined whether the concentration of the combustible gas is within the threshold value G1 in the composition information of the carbon dioxide-rich gas detected by the composition detector 44 . Here, the threshold value G1 is a sufficiently low concentration in the carbon dioxide rich gas, and can be set to about 0.01 to 5 vol%, more preferably in the range of 0.01 to 1 vol%. When the concentration of the combustible gas is higher than the threshold value G1, the flow control valve 42 is controlled to increase the flow rate of the cathode offgas branched to the branched cathode offgas pipe P6-2. As a result, the amount of oxygen that permeates the gas-permeable membrane 23 and moves to the combustion space 22A increases, and the combustible gas contained in the carbon dioxide-rich gas can be reduced by causing a combustion reaction in the combustion space 22A.

The carbon dioxide-rich gas sent to the carbon dioxide gas pipe P10 is sent to the compressor 68 of the carbon dioxide gas liquefying section 66 and compressed, and the compressed carbon dioxide-rich gas is sent to the cooling device 70 . The cooling device 70 cools the compressed carbon dioxide-rich gas with cooling water from the exhaust heat input type absorption chiller 36 to generate liquefied carbon dioxide.

Since the exhaust heat input type absorption chiller 36 uses the exhaust heat of the air electrode off-gas to generate cold heat, it is a type of chiller that compresses and expands the refrigerant by driving the compressor with a motor (for example, a turbo It is possible to efficiently generate cold energy (used for cooling water to make cooling water) with less power than when cold energy is generated by a refrigerator or the like.

From the state diagram of carbon dioxide gas shown in FIG. 3, as an example, carbon dioxide gas compressed to 4 MPa or more is liquefied when cooled to a temperature lower than the critical temperature (31.1° C.) of carbon dioxide gas.
In the carbon dioxide gas liquefying unit 66 of the present embodiment, as an example, carbon dioxide gas is compressed to 4 MPa by the compressor 68, and then in the cooling device 70, the compressed carbon dioxide gas is cooled to −5° C. to 12° C. with cooling water. liquefied carbon dioxide is obtained by cooling with Note that the pressure of the carbon dioxide gas and the cooling temperature are not limited to the above values, and can be changed as appropriate.

(control of liquefaction)
Any one of the temperature (measured by the temperature sensor 74) and pressure (measured by the pressure sensor 76) of the high-pressure carbon dioxide gas that has passed through the compressor 68, or the amount of carbon dioxide gas remaining without being liquefied According to one or more measurement results, the control unit determines the temperature of the cooling water supplied to the cooling device 70 (measured by the temperature sensor 80) and the flow rate (measured by the flow sensor (not shown)). The operation of the refrigerator 36 and the operation of the circulation pump 78 are controlled to efficiently convert carbon dioxide gas into liquefied carbon dioxide.

That is, in the present embodiment, the control unit calculates the amount of cold heat for maximizing the amount of liquefaction of carbon dioxide gas according to the temperature and pressure of the collected carbon dioxide gas or the amount of carbon dioxide gas remaining at the time of liquefaction. , the temperature of the cooling water can be lowered accordingly, the flow rate of the circulating cooling water can be increased, or both of these can be used in combination.

In addition, inside the cooling device 70, liquefied carbon dioxide accumulates at the bottom, and unliquefied carbon dioxide gas remains above the liquefied carbon dioxide, so the liquid surface of the liquefied carbon dioxide accumulated inside the cooling device 70 By measuring the level, it is possible to indirectly measure the amount of carbon dioxide gas that remains without being liquefied inside the cooling device 70 (the internal space volume of the cooling device 70 is known).

The liquefied carbon dioxide generated in the carbon dioxide gas liquefying section 66 in this manner is sent to the tank 84 via the pipe P15 and the pump 82 and stored therein. Note that the liquefied carbon dioxide stored in the tank 84 can also be used for commercial and industrial purposes as in the conventional case.

In the fuel cell power generation system 10A of the present embodiment, since the first fuel cell stack 12 and the second fuel cell stack 14 to the tank 84 are continuously connected and provided on-site, during power generation, Liquefied carbon dioxide can be efficiently produced continuously and stored in the tank 84 . Note that the liquefied carbon dioxide stored in the tank 84 may be transported by a lorry 86 or the like, or may be transported by a pipeline or the like.

In the fuel cell power generation system 10A of the present embodiment, since the second fuel electrode off-gas sent from the second fuel electrode 14A of the second fuel cell stack 14 is burned in the combustion unit 22, the second fuel cell stack 14 The amount of unreacted fuel gas used for power generation in the second fuel cell stack 14 increases compared to the case where the first fuel electrode off-gas is burned before it is used for power generation. Therefore, power generation efficiency in the second fuel cell stack 14 can be enhanced.

Further, in the combustion section 22, carbon dioxide and water vapor are generated by a combustion reaction between combustible gas contained in the second fuel electrode off-gas and oxygen. Therefore, the combustible gas can be reduced from the second anode off-gas, and high-concentration carbon dioxide can be recovered. In addition, only oxygen in the air electrode off-gas is supplied to the combustion unit 22, and the second fuel electrode off-gas contains a smaller amount of unreacted fuel gas than the first fuel electrode off-gas, and carbon dioxide high content of Therefore, the amount of unreacted fuel gas to be burned in the combustion section 22 and the amount of oxygen required to burn the unreacted fuel gas can be reduced.

Further, since the fuel cell power generation system 10A of the present embodiment has the branched air electrode offgas pipe P6-2 branched from the air electrode offgas pipe P6, the composition of the carbon dioxide rich gas detected by the composition detector 44 is Based on the information, it is possible to easily adjust the cathode offgas flow rate branched to the branched cathode offgas pipe P6-2. As a result, the amount of oxygen flowing into the combustion space 22A of the combustion section 22 can be adjusted so that the amount of combustible gas and oxygen contained in the combustion off-gas is lower than the predetermined threshold value.

Furthermore, in the fuel cell power generation system 10A of the present embodiment, the amount of water to be condensed by the condenser 26 is adjusted based on the composition information of the carbon dioxide-rich gas detected by the composition detection unit 44. Carbon dioxide concentration can be increased.

Further, in the fuel cell power generation system 10A of the present embodiment, since the hydrogen ion conducting solid oxide fuel cell is used in the fuel cell stack, water vapor is not generated at the first fuel electrode 12A. Therefore, since the amount of water vapor contained in the first fuel electrode off-gas is reduced, the power generation efficiency of the second fuel cell can be improved. Moreover, since the amount of water vapor contained in the second fuel electrode off-gas is also reduced, the amount of water vapor to be removed from the second fuel electrode off-gas can be reduced.

In addition, in the fuel cell power generation system 10A of the present embodiment, by arranging the combustion section 22 adjacent to the gas permeable membrane 23 of the oxygen separation section 24, the combustion section 22 and the oxygen separation section 24 are integrally formed to form a compact oxygen-permeable membrane. A membrane combustor 20 can be constructed.

In addition, in the fuel cell power generation system 10A of the present embodiment, the heat of the air electrode off-gas is used to generate cold heat in the exhaust heat input type absorption chiller 36, so the first fuel cell stack 12 and the second fuel cell stack Exhaust heat from 14 can be effectively used. Further, since the air electrode off-gas contains a large amount of water vapor, the water vapor is condensed during heat exchange in the exhaust heat input type absorption chiller 36, and the heat of condensation can also be effectively used.

In addition, in the fuel cell power generation system 10A of the present embodiment, the control unit detects the amount of cooling water stored in each buffer tank of the cooling tower 38, the cooling water circulation passage 26A, and the cooling water circulation passage 70A for liquefaction from the liquid level sensor. It is grasped based on the detection data, and when it is determined that the amount of stored cooling water is less than the preset lower limit, the solenoid valve and the pump 27A are controlled, and the water used for the cooling water is stored in the water tank 27. can be replenished from In this way, when the cooling water runs short, there is no need to supply water from an external water supply or the like, and the amount of external dependence on water can be reduced.

In the present embodiment, carbon dioxide is separated from the combustion off-gas by removing water vapor in the combustion off-gas by condensing it with the condenser 26, but carbon dioxide is separated from the combustion off-gas by other means, for example, a carbon dioxide separation membrane. Alternatively, carbon dioxide may be separated by a so-called PSA (Pressure Swing Adsorption) device that separates and produces gas by changing the pressure using an adsorbent.

In addition, in the combustor 20 with an oxygen permeable membrane of the present embodiment, the outer side is the combustion section 22 and the inner side is the oxygen separation section 24, but the outer side may be the oxygen separation section 24 and the inner side may be the combustion section 22. good.

[Second embodiment]
Next, a second embodiment of the invention will be described. In this embodiment, the same reference numerals are assigned to the same parts as in the first embodiment, and detailed description thereof will be omitted.

FIG. 4 shows a fuel cell power generation system 10B according to a second embodiment of the invention. The fuel cell power generation system 10B is a system that produces carbon from carbon dioxide gas. A carbon production section 166 is provided on the downstream side of the carbon dioxide gas pipe P10 instead of the carbon dioxide gas liquefaction section 66 of the fuel cell power generation system 10B of the first embodiment.

In this embodiment, one end of the fuel gas pipe P1 is connected to the first fuel electrode 12A of the first fuel cell stack 12, and the other end of the fuel gas pipe P1 is connected to a fuel gas source (not shown). there is
Further, in the present embodiment, the circulating gas pipe P3 is branched from the second anode offgas pipe P7-2, and the circulating gas pipe P3 is connected to the fuel gas pipe P1. A circulation gas blower B3 is provided in the circulation gas pipe P3.

A first heat exchanger 30 is provided in an intermediate portion of the fuel gas pipe P1. A combustion off-gas pipe P8 for delivering combustion off-gas is connected to the outlet side of the combustion space 22A of the combustor 20 with an oxygen permeable membrane. is connected to the condenser 26 . In the first heat exchanger 30, the fuel gas is heated by heat exchange between the fuel gas and the combustion off-gas.

The combustion off-gas that has passed through the first heat exchanger 30 is sent to the condenser 26, and the combustion off-gas from which water vapor has been removed by the condenser 26 becomes a carbon dioxide-rich gas with a high carbon dioxide concentration. It is sent to the gas pipe P10 and sent to the composition detection unit 44 . The composition detector 44 detects the composition of the carbon dioxide-rich gas and transmits the detected information to the controller.

Based on the composition information transmitted from the composition detection unit 44, the control unit controls the flow rate adjustment valve 42 to adjust the amount of air electrode offgas branched to the branch air electrode offgas pipe P6-2, and exhaust heat input type The absorption chiller 36 controls the temperature of the cooling water sent to the cooling water circulation passage 26A. Specifically, the controller executes a flow rate adjustment process and a cooling water temperature adjustment process.
The carbon dioxide gas sent to the carbon dioxide gas pipe P10 is sent to the carbon production section 166 .

(Structure of carbon production department)
The carbon production unit 166 includes a water electrolysis device 170, a pipe P114, a hydrogen blower 172, a pipe P115, an oxygen blower 174, an oxygen tank 176, a powdered carbon generator 178, and the like.

Water in the water tank 27 is supplied to the water electrolysis device 170 through a pipe P116, a pump 180, and a water purification device 182. The water purifier 182 purifies the water from the water tank 27 (removes foreign matter, adjusts pH, etc.). The water electrolysis device 170 can generate hydrogen gas and oxygen gas by electrolyzing purified water using power obtained from the first fuel cell stack 12 and the second fuel cell stack 14 . . The water electrolysis device 170 can also electrolyze water using power (so-called “clean energy”) obtained by renewable energy generation (not shown). Examples of renewable energy power generation include photovoltaic power generation, solar thermal power generation, hydroelectric power generation, wind power generation, geothermal power generation, wave power generation, temperature difference power generation, biomass power generation, and the like. good. That is, from the viewpoint of reducing carbon dioxide in the atmosphere or suppressing the release of carbon dioxide into the atmosphere, the DC power obtained in the first fuel cell stack 12 and the second fuel cell stack 14 and the regenerated It is preferable to use power obtained from renewable energy power generation.

The water electrolysis device 170 electrolyzes water using the DC power obtained from the first fuel cell stack 12 and the second fuel cell stack 14 or the power obtained from renewable energy power generation. , water can be electrolyzed more efficiently than in the case where the AC power of a power generator that emits carbon dioxide gas is converted into DC power and used for electrolysis. Note that the water electrolysis device 170 is controlled by a control unit.

Hydrogen gas generated by the water electrolysis device 170 is sent to the powdered carbon generator 178 via the pipe P114 and the hydrogen blower 172, and oxygen gas is sent to the oxygen tank 176 via the pipe P115 and the oxygen blower 174. It is stored in tank 176 . The hydrogen blower 172 and the oxygen blower 174 are controlled by the controller.

(Configuration of powder carbon generator)
As shown in FIG. 5 , the powdered carbon generator 178 includes a heater 184 , a shift reactor 186 , a cooler 188 and a carbon deposition separation section 200 .

The heater 184 includes an outer cylinder 202, a cylindrical partition wall 204 disposed inside the outer cylinder 202, and a closing member that closes the openings of the outer cylinder 202 and the cylindrical partition wall 204 on the ends in the cylinder axis direction. 206 has a sealed multiple cylindrical shape.

Between the outer cylinder 202 and the partition wall 204 is a gas combustion channel 208 as the first channel of the present invention, and the inner peripheral side of the cylindrical partition wall 204 is the second channel of the present invention for raising the temperature. A partition wall 204 separates the gas combustion flow path 208 from the temperature raising section 210 .

A helical passage forming member 212 having a helical shape is disposed inside the gas combustion flow path 208 , and is formed in a helical shape toward the cylinder axis direction of the heater 184 .

In the heater 184, the hydrogen gas and oxygen gas sent from the water electrolysis device 170 are supplied to the gas combustion flow path 208, and the carbon dioxide gas sent from the condenser 26 and the hydrogen gas sent from the water electrolysis device 170 Gas is supplied to the temperature raising unit 210 .
In the gas combustion channel 208, the hydrogen gas and the oxygen gas undergo a combustion reaction, and the heat generated by the combustion reaction heats the carbon dioxide gas and the hydrogen gas passing through the temperature raising section 210 to a high temperature, for example, 1000 to 1200°C. can be heated to

A shift reactor 186 is arranged downstream of the temperature raising device 201, and carbon dioxide gas and hydrogen gas heated to a high temperature are supplied to the shift reactor 186. As shown in FIG.
In the shift reactor 186, as shown in the following formula (5), carbon dioxide gas can undergo a shift reaction with carbon monoxide under a hydrogen gas atmosphere.
_CO2 + _H2- >CO+ _H2O (5)
Here, known catalysts can be used to accelerate the reaction.

A cooler 188 is arranged downstream of the shift reactor 186, and the carbon monoxide gas and water vapor discharged from the shift reactor 186 are cooled by the cooler 188 to a predetermined temperature, for example, 600° C. or less. The temperature is adjusted so that

A carbon deposition separation section 200 is arranged downstream of the cooler 188 , and temperature-controlled carbon monoxide gas and water vapor discharged from the cooler 188 are introduced into the carbon deposition separation section 200 . The carbon deposition separation section 200 is provided with a helical flow path 214 formed in a helical shape and having an increased passage length.

In the carbon deposition separation section 200, the carbon monoxide in the gas is converted into carbon and carbon dioxide by the following formula (6) in the spiral channel 214 with a longer channel length.
2CO→C+ _CO2 (6)
Note that the above formula (6) is an exothermic reaction.
Furthermore, in the spiral flow path 214 of the carbon deposition separation unit 200, simultaneously with the reaction of the above formula (6), the reaction of producing carbon and water from the carbon dioxide gas and the hydrogen gas proceeds according to the following formula (7).
_CO2 + _2H2- >C+ _2H2O (7)
In addition, in the carbon deposition separation section 200, a known reduction catalyst is provided inside the spiral flow path 214 in order to promote the reaction.

In this manner, the carbon deposition separation unit 200 allows carbon to be deposited and immobilized.
Note that C produced by the reduction reaction of the formula (6) above is powdered carbon and can be discharged from the lower portion of the spiral flow path 214 . Further, the H ₂ O generated in the reduction reaction of the formula (6) is specifically water vapor, and the water vapor is sent to the condenser 26 via the pipe P117.

The memory of the control unit of the present embodiment stores data, procedures, and the like necessary for flow rate adjustment processing, cooling water temperature adjustment processing, and processing during normal operation, which will be described later. The control unit is connected to the flow control valve 42, the composition detection unit 44, the exhaust heat input type absorption chiller 36, and the like. The control unit controls the flow control valve 42, the composition detection unit 44, the exhaust heat input type absorption chiller 36, and the like.

In the fuel cell power generation system 10B, pumps, blowers, and other accessories are driven by electric power generated by the fuel cell power generation system 10B. In order to efficiently use the direct current power generated by the fuel cell power generation system 10B without converting it to alternating current, the auxiliary equipment is preferably driven by direct current.

(action, effect)
Next, the operation of the fuel cell power generation system 10B of this embodiment will be described.

The water electrolyzer 170 electrolyzes the water sent from the water purifier 182 to generate hydrogen gas and oxygen gas. 184. Also, the carbon dioxide-rich gas discharged from the condenser 26 and the hydrogen gas sent from the water purification device 182 are supplied to the temperature raising section 210 of the temperature raising device 184 .

To start the powdered carbon generator 178 , hydrogen gas and oxygen gas are first reacted (burned) in the gas combustion flow path 208 of the heater 194 . The combustion flame generated by the combustion reaction between the hydrogen gas and the oxygen gas and the high-temperature exhaust gas (water vapor) pass through the gas combustion channel 208 , and the heat of the combustion flame and the exhaust gas rises through the partition wall 204 . It is transmitted to the warm section 210 . The gas combustion channel 208 is spirally formed in the direction of the cylinder axis of the heater 184, and has a long channel length. It can be sufficiently applied to the temperature raising section 210 . That is, the residence time of the combustion flame and exhaust gas can be increased in the heater 184 . As a result, the carbon dioxide gas and the hydrogen gas supplied to the temperature raising unit 210 can be sufficiently heated, and the carbon dioxide gas and the hydrogen gas can be reliably raised to a predetermined temperature (for example, 1000 to 1200° C.). can be warmed. In the gas combustion channel 208, water (steam) generated by the reaction between the hydrogen gas and the oxygen gas is discharged from the lower end to the outside.

The carbon dioxide gas and the hydrogen gas, which have been heated to a predetermined temperature in the temperature raising unit 210, are supplied to the shift reactor 186, where the carbon dioxide gas undergoes a shift reaction to carbon monoxide in a hydrogen gas atmosphere, resulting in carbon monoxide. and water are produced.

The carbon monoxide gas and water vapor discharged from the shift reactor 186 are sent to the cooler 188 to be cooled to a predetermined temperature (for example, 600° C. or lower) and then supplied to the carbon deposition separation section 200 .
In the carbon deposition separation section 200 , powdered carbon and water (steam) are generated from the carbon dioxide gas and the hydrogen gas inside the spiral flow path 214 .
Since the spiral flow path 214 is formed in a spiral shape and has a long flow path length, the residence time of the gas introduced into the inside can be increased, and the above equations (6) and (7) can be obtained. Sufficient time can be taken for the reaction, and powdered carbon can be efficiently obtained without wasting carbon dioxide gas.
Note that the water vapor from the carbon deposition separation unit 200 is sent to the condenser 26 via the pipe P117 and cooled by the condenser 26 to become water.

In the fuel cell power generation system 10B of the present embodiment, the first fuel cell stack 12 and the second fuel cell stack 14 to the carbon production unit 166 are continuously connected and provided on-site. can efficiently produce powdered carbon continuously.
Powdered carbon is not released into the atmosphere as carbon dioxide gas unless it is ignited and burned, and can suppress the release of carbon dioxide gas into the atmosphere.

In addition, powdered carbon can be easily transported to a storage site, and if it is not placed under conditions where an ignition source and oxygen are available, it can be stably fixed for a long period of time even if it is simply dumped on the ground or landfilled underground. becomes possible. The produced powdery carbon can also be used commercially and industrially as carbon black or the like.

In the fuel cell power generation system 10B of the present embodiment, powdered carbon is produced from carbon dioxide gas, but a carbon product manufacturing device 216 that converts powdered carbon into graphite, carbon nanotubes, diamond, or the like may be further added. In the carbon product manufacturing apparatus 216, for example, the collected powdered carbon is processed into high temperature (electric heater temperature rise), high pressure (electric high pressure press ) environment, synthetic diamond powder can be obtained by a known technique. Further, for example, the collected powdered carbon is carbonized by a known technique such as an arc discharge method, a laser ablation method, a CVD method, etc., using power generated by the fuel cell power generation system 10B or power from renewable energy. Nanotubes can be obtained. Furthermore, graphite can be obtained from the collected powdered carbon by a known technique using power generated by the fuel cell power generation system 10B, power generated by renewable energy, or the like.

By using graphite, carbon nanotubes, or diamond powder as the carbon powder, it does not burn easily even if there is an ignition source or oxygen, and even if it is piled up on the ground, it can safely and stably fix carbon for a long time. As a result, there are no restrictions on storage locations, and energy loss and costs associated with transportation and injection can be reduced. Graphite can be used in pencil leads and brake pads for automobiles, carbon nanotubes can be used as semiconductors and structural materials, and synthetic diamond powder can be used in construction and as diamond cutter blades for machine tools. can.

Note that this carbon product manufacturing device 216 is also a part of the carbon manufacturing section 166, and is provided on-site in the fuel cell power generation system 10B. In addition, products manufactured using powdered carbon are not limited to the above carbon products, and carbon materials such as carbon nanohorns and fullerenes may be manufactured by known techniques and used in commerce and industry.

In the temperature riser 184 of the present embodiment, the spiral gas combustion flow path 208 is formed on the outside and the non-spiral temperature raising section 210 is formed on the inside. 208, and a temperature raising portion 210 having a non-helical outer side.

In addition, in the temperature raising device 184 of the present embodiment, the temperature raising part 210 does not have a spiral flow path, but the temperature raising part 210 may have a spiral flow path.

[Other embodiments]
Although one embodiment of the fuel cell power generation system of the present invention has been described above, the present invention is not limited to the above, and can be implemented in various modifications without departing from the spirit of the present invention. It goes without saying that

Other fuel cells such as molten carbonate fuel cells (MCFC), phosphoric acid fuel cells (PAFC), and polymer electrolyte fuel cells (PEFC) can also be used as the fuel cell of the present invention.

10A Fuel cell power generation system 10B Fuel cell power generation system 12 First fuel cell stack (fuel cell)
12A first fuel electrode (fuel electrode)
12B first air electrode (air electrode)
14 Second fuel cell stack (fuel cell)
14A second fuel electrode (fuel electrode)
14B Second air electrode (air electrode)
20 Combustor with oxygen permeable membrane (reactor)
22A combustion space (first flow path, reaction path)
23 Gas permeable membrane (partition wall)
23A Oxidation catalyst film (catalyst)
24A air flow path (second flow path, air electrode off-gas passage)
28 outer spiral passage forming member (partition member)
29 inner spiral passage forming member (partition member)
170 water electrolysis device 184 temperature riser (reaction device)
200 carbon deposition separation section (carbon deposition section)
204 partition wall 208 gas combustion channel (first channel)
212 Spiral passage forming member (partition member)
210 temperature raising unit (second flow path)
P6-2 Branch air electrode off-gas pipe (second introduction path)
P7-2 2nd anode off-gas pipe (1st introduction path)

Claims (4)

a partition having a cylindrical shape and separating the inner first channel and the outer second channel;
a catalyst provided in at least one of the first flow path and the second flow path to promote a reaction between gases;
It is provided in at least one of the first flow path and the second flow path, and the inside of the flow path extends from one end to the other end in the cylinder axis direction as compared with a flow path formed linearly in the cylinder axis direction. a spiral partition member in the direction of the cylinder axis so that the flow path length of the
with
The partition wall includes a gas permeable membrane that allows the gas to be subjected to reaction to permeate from one of the first channel and the second channel to the other.
Reactor. The reactor according to claim 1 , wherein the catalyst is laminated on the gas permeable side of the gas permeable membrane. Electricity is generated by a fuel gas containing a carbon compound and supplied to the fuel electrode and an oxidant gas containing oxygen and supplied to the air electrode, and the fuel gas unreacted from the fuel electrode and the first carbon dioxide gas. a fuel cell in which a fuel electrode off-gas containing oxygen is discharged from the air electrode;
One of the first channel and the second channel is a reaction channel provided with an oxidation catalyst as the catalyst and the partition member, the gas permeable membrane is an oxygen permeable membrane, and the first channel and the reactor according to claim 2, wherein the other of the second flow paths is an air electrode off-gas passage,
a first introduction path for introducing the fuel electrode off-gas into the reaction path;
a second introduction path for introducing the cathode off-gas into the cathode off-gas passage;
with
A fuel cell power generation system in which second carbon dioxide is generated in the reaction path by an oxidation reaction between the carbon compound in the fuel electrode offgas and oxygen that has permeated through the oxygen permeable membrane from the first flow path. Electricity is generated by a fuel gas containing a carbon compound and supplied to the fuel electrode and an oxidant gas containing oxygen and supplied to the air electrode, carbon dioxide gas is discharged from the fuel electrode, and oxygen is contained from the air electrode. a fuel cell from which air electrode off-gas is discharged;
a water electrolysis device that electrolyzes water to generate hydrogen gas and oxygen gas;
It has a cylindrical shape and has an outer first flow path and an inner second flow path arranged with a partition wall therebetween. a spiral partition member is formed in the direction of the cylinder axis so that the channel length from one end to the other end in the cylinder axis direction is longer than the channel formed in the first channel; a reactor in which the hydrogen gas and the oxygen gas are reacted in and the carbon dioxide gas and the hydrogen gas are supplied to the second flow path;
a carbon deposition unit to which the carbon dioxide gas and the hydrogen gas are supplied from the second flow path and carbon is generated from the carbon dioxide gas;
A fuel cell power generation system.

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