JP2020087789A - Reactor and fuel cell power generation system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a reaction device capable of promoting a reaction. SOLUTION: A combustion combustor 20 with an oxygen permeation film is arranged on a combustion space 22A into which a fuel electrode off gas can flow in and an air permeation film 23 on the inner peripheral side of the combustion space 22A so as to allow an air electrode off gas to flow in. The combustion space 22A and the air flow path 24A are spirally formed in the direction of the cylinder axis, and the combustion space 22A includes the combustible gas and oxygen in the second fuel electrode off gas. A combustion reaction occurs, producing carbon dioxide and water vapor. [Selection diagram] Fig. 1

Description

The present invention relates to a reaction device and a fuel cell power generation system that includes the reaction device and that generates electric power using a carbon compound fuel.

When a carbon compound fuel is used in a fuel cell power generation system, carbon dioxide gas is contained in the exhaust gas discharged from the fuel cell. It is considered to separate carbon dioxide gas from this exhaust gas (see, for example, Patent Documents 1 to 5).

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

By liquefying carbon dioxide gas into liquefied carbon dioxide, it becomes easy to transport, press-fit and fix into the reservoir, and use for commercial and industrial purposes.
Since the exhaust gas contains gas (impurity) other than carbon dioxide gas, it is necessary to remove gas other than carbon dioxide gas in order to obtain liquefied carbon dioxide with few impurities. Although there are devices that obtain high-concentration carbon dioxide gas by reacting unburned components of exhaust gas with oxygen, it is demanded to accelerate the reaction when obtaining carbon dioxide gas.

It is also known to generate and store carbon from the separated carbon dioxide gas in order to prevent the carbon dioxide gas from being released into the atmosphere. There is known a carbon production device that produces carbon by reacting (reducing) carbon dioxide gas and hydrogen under a catalyst (see, for example, Patent Document 5). The reduction reaction requires a high temperature, and when starting the reduction reaction, for example, it is necessary to burn hydrogen to rapidly heat the carbon dioxide gas, hydrogen, and the catalyst with the heat of the combustion gas.
As described above, various reactions are performed in the fuel cell power generation system, and it is desired to promote the reactions.

The present invention has been made in consideration of the above facts, and an object of the present invention is to provide a reactor capable of promoting a reaction and a fuel cell power generation system including the reactor.

The reactor according to claim 1, wherein the partition wall has a tubular shape and separates an inner first flow path and an outer second flow path, and at least one of the first flow path and the second flow path. A catalyst that is provided and that promotes a reaction between gases, and a partition member that is provided in at least one of the first flow path and the second flow path and that has a spiral shape inside the flow path in the direction of the cylinder axis, Is equipped with.

In the reactor according to the first aspect, one or a plurality of types of gas can be passed through the first flow path, and one or a plurality of types of gas can be flowed through the second flow path. The same gas or different gases can be passed through the first flow path and the second flow path.
Further, different kinds of gas can be reacted with each other in the first flow path or the second flow path formed in a spiral shape.

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

Since the flow path formed in a spiral shape in the cylinder axis direction can have a longer flow path length from one end to the other end as compared with a flow path formed in a straight line in the cylinder axis direction, In the flow path, it is possible to lengthen the time for which the gases react with each other, the residence time of the gases, and the residence time of the reaction product generated by the reaction of the gases.

For example, one of the first flow path and the second flow path is formed in a spiral shape, two different gases are introduced from one end side of the spiral flow path, and heat generation of one gas and the other gas The reaction product generated by the reaction is caused to flow in a long flow path for a long time, and the heat generated by the exothermic reaction is adjoined for a long time (in contrast to a linear flow path) in the first flow path or the second flow path. It can be sufficiently applied to the other side of the road.
Further, 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, It is also possible to reliably cause an endothermic reaction between different gases in the other channel of the second channel.

Further, two different kinds of gas can be introduced from one end side of the spiral flow path, and one gas and the other gas can react with each other in a long flow path over time.

The invention according to claim 2 is the reaction apparatus according to claim 1, wherein the partition wall is a gas permeation that allows a gas used for a reaction to permeate from one of the first flow path and the second flow path to the other. Equipped with a membrane.

The reaction apparatus according to claim 2, wherein the partition wall that separates the first flow path and the second flow path allows the gas used in the reaction from one of the first flow path and the second flow path to permeate to the other. Since it has a membrane, the gas in the first channel permeates the gas permeable membrane and flows into the second channel, and the gas in the second channel permeates the gas permeable membrane and flows into the first channel. Can be made
Therefore, the gas in the first flow path and the gas in the second flow path can react with each other in the first flow path or the second flow path. Further, the reaction between gases can be promoted by a catalyst.

According to a third aspect of the present invention, in the reaction apparatus according to the second aspect, the catalyst is laminated on the gas permeable side of the gas permeable membrane.

In the reaction device according to the third aspect, since the catalyst is provided on the gas permeable side of the gas permeable membrane, the reaction between the gases can be promoted in the gas permeable side flow path.

Further, if the flow path for causing the reaction between the gases is formed in a spiral shape, the reaction time can be made long in the spiral flow path.

The fuel cell power generation system according to claim 4 generates power by 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 unreacted from the fuel electrode. A fuel cell in which the fuel electrode off gas containing the fuel gas and the first carbon dioxide gas is discharged, and the air electrode off gas containing oxygen is discharged from the air electrode; and the first flow path and the second flow path. One is a reaction path provided with an oxidation catalyst as the catalyst and the partition member, the gas permeable film is an oxygen permeable film, and the other of the first flow path and the second flow path is an air electrode. The reactor according to claim 3, which is an off gas passage, a first introduction passage for introducing the fuel electrode off gas into the reaction passage, and a second introduction for introducing the air electrode off gas into the air electrode off gas passage. A second passage, and second carbon dioxide is generated in the reaction passage by an oxidation reaction between the carbon compound in the fuel electrode off-gas and oxygen that has permeated the oxygen permeable membrane from the first passage. ..

In the fuel cell power generation system according to claim 4, a fuel gas containing a carbon compound is supplied to a fuel electrode of the fuel cell, and an oxidant gas containing oxygen is supplied to an air electrode, whereby the fuel cell generates power, The fuel electrode off gas containing unreacted fuel gas and the first carbon dioxide gas is discharged from the fuel electrode, and the air electrode off gas containing oxygen is discharged from the air electrode.

In the reaction device, as an example, the fuel electrode off-gas is introduced into the first flow path as the reaction path via the first introduction path, and the air electrode off-gas is introduced into the second flow path as the air electrode off-gas passage path via the second introduction path. When introduced into the flow channel, in the first flow channel, the oxidation catalyst promotes the oxidation reaction between the oxygen that has permeated the gas permeable membrane and the unreacted carbon compound of the fuel gas to generate the second carbon dioxide gas. Is generated. As a result, the first flow path 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.
Moreover, by forming the first flow path in a spiral shape, it is possible to lengthen the oxidation reaction time in the flow path. Thereby, a high concentration carbon dioxide gas can be obtained.
The second flow path may be formed in a spiral shape like the first flow path.

The fuel cell power generation system according to claim 5 generates power by 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 in which gas is discharged and an air electrode off-gas containing oxygen is discharged from the air electrode, a water electrolysis device that electrolyzes water to generate hydrogen gas and oxygen gas, and has a cylindrical shape and is outside. A first flow path and an inner second flow path that is arranged with a partition wall therebetween, and a partition member is formed in the first flow path, the partition member having a spiral shape inside the flow path in the direction of the cylinder axis. A reaction device in which the hydrogen gas and the oxygen gas are reacted in the first flow path, and the carbon dioxide gas and the hydrogen gas are supplied to the second flow path; Carbon dioxide gas and the hydrogen gas are supplied, a carbon deposition portion in which carbon is generated from the carbon dioxide gas,
Have.

In the fuel cell power generation system according to claim 5, a fuel gas containing a carbon compound is supplied to a fuel electrode of the fuel cell, and an oxidant gas containing oxygen is supplied to an 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.

The water electrolysis device electrolyzes water to generate hydrogen gas and oxygen gas.

In the reaction device, hydrogen gas and oxygen gas supplied from the water electrolysis device can be supplied to the spirally formed first flow path to cause a combustion reaction. High-temperature steam is generated by burning and reacting hydrogen and oxygen, and the heat of the steam is transferred to the second flow path via 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 flow path to form a mixed gas, which is heated by the heat of the combustion reaction.

Here, since the high-temperature steam passes through the first channel having a long path length formed in a spiral shape and is discharged from the other end side, it takes time for the steam to be discharged from the other end side. Therefore, the heat of the water vapor 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 the carbon dioxide gas and the hydrogen gas in the second flow path.

The heated mixed gas is supplied to the carbon depositing portion on the downstream side, and carbon is internally generated from the carbon dioxide gas.

According to the reaction device and the fuel cell power generation system of the present invention, it is possible to efficiently cause a reaction.

1 is a schematic diagram of a fuel cell power generation system according to a first embodiment. FIG. 3 is a cross-sectional view taken along the axis of the combustor with an oxygen permeable membrane. It is a phase diagram of carbon dioxide. It is a schematic diagram of the fuel cell power generation system concerning a 2nd embodiment. It is a block diagram which shows the powder carbon generator of the fuel cell power generation system which concerns on 2nd Embodiment.

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

As shown in FIG. 1, the first fuel cell stack 12 is a hydrogen ion conductive 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 a first fuel electrode (fuel electrode) 12A and a first air electrode (air electrode) 12B, which are respectively laminated on the back surface.

The basic structure of the second fuel cell stack 14 is the same as that of the first fuel cell stack 12, and the second fuel electrode 14A corresponding to the first fuel electrode 12A and the first fuel electrode 12B corresponding to the first air electrode 12B. The second air electrode 14B and the electrolyte layer 14C corresponding to the electrolyte layer 12C are included.

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 the reformer 54 described later. ing. Fuel gas is delivered from the reformer 54 to the first fuel electrode 12A. Although methane is used as the fuel gas in the present embodiment, it is not particularly limited as long as it is a gas that can generate hydrogen by reforming, and 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 preferable. The hydrocarbon fuel may be a mixture of the above-mentioned lower hydrocarbon gas, and the above-mentioned lower hydrocarbon gas may be a gas such as natural gas, city gas or LP gas. When the raw material gas contains impurities, a desulfurizer or the like is required, but it is omitted in FIG.

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

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

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

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

(Fuel electrode reaction)
_{^{H 2 → 2H + + 2e -}} ... (3)

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

The oxidant gas (air) is supplied to the first air electrode 12B of the first fuel cell stack 12 from the 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 the second heat exchanger 32, and the air flowing through the oxidant gas pipe P5 is heated by heat exchange with the air electrode off-gas flowing through the air electrode off-gas pipe P6 described later. The heated air is supplied to the first air electrode 12B.

In the first air electrode 12B, as shown in the following formula (4), hydrogen ions moving from the first fuel electrode 12A through the electrolyte layer 12C and electrons moving from the first fuel electrode 12A through the external circuit are generated. , Reacts with oxygen in the oxidant gas to generate 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 air electrode off gas is discharged from the first air electrode 12B to the air electrode off gas pipe P6. The oxidant gas pipe P5 and the air electrode off-gas pipe P6 are similarly connected to the second air electrode 14B, and the first air electrode 12B and the second air electrode 14B are connected in parallel.

One end of a 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 first fuel electrode off-gas pipe P7 of the second fuel cell stack 14. It is connected to the two 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, steam and the like.

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

In the second fuel cell stack 14, the same power generation reaction as in the first fuel cell stack 12 is performed, and the air electrode off gas is sent from the second air electrode 14B to the air electrode off gas pipe P6. The air electrode off-gas pipe P6 connected to the second air electrode 14B is branched on the upstream side of the confluence portion with the air electrode off-gas pipe P6 connected to the first air electrode 12B, and a branched air electrode off-gas pipe P6. -2 is formed. The branch air electrode offgas pipe P6-2 is provided with a flow rate adjusting valve 42 capable of adjusting the flow rate. The flow rate adjustment valve 42 is connected to the control unit. The flow rate adjustment valve 42 is controlled by the control unit, and the flow rate of the air electrode off gas branched to the branch air electrode off gas pipe P6-2 is adjusted. The downstream end of the branched air electrode off-gas 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 arranged inside the outer cylinder 20A, an outer cylinder 20A and a cylindrical gas permeable membrane 23. And a closing member 20B that closes an opening portion on the end side in the cylinder axis direction, and has a multi-cylindrical shape with a sealed inside.

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

The combustion part 22 is provided with an outer spiral passage forming member 28 having a spiral shape inside, and has a combustion space 22A serving as a first flow path of the present invention, which has a spiral shape in the cylinder axis direction of the outer cylinder 20A. Has been formed.
The outer spiral passage forming member 28 is, for example, a band-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 portion 24 is provided with an inner spiral passage forming member 29 having a spiral shape inside, and is an air flow passage as a second flow passage of the present invention, which has a spiral shape in the cylinder axis direction of the outer cylinder 20A. 24A is formed.
The inner spiral passage forming member 29 is, for example, a band-shaped member formed in a spiral shape, and the outer peripheral edge thereof is fixed to the inner peripheral surface of the gas permeable membrane 23. The inner spiral passage forming member 29 may have a spiral step 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 (electroconductive property) such as LSCF (lanthanum-strontium-cobalt-iron composite oxide) is used. (An oxide showing a) can be used, and a material other 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 of a material such as nickel or ruthenium in the form of a catalyst film.

As shown in FIGS. 1 and 2, the other end of the second fuel electrode off-gas pipe P7-2 is connected to the inlet of the combustion space 22A, and the branch air electrode off-gas pipe P6 is connected to the inlet of the air passage 24A. The downstream end of -2 is connected.

The second air electrode off-gas is supplied to the air flow path 24A, and oxygen contained in the second air electrode off-gas permeates the gas permeable membrane 23 and moves to the combustion space 22A. The second air electrode off-gas that does not move to the combustion space 22A is exhausted to the outside from the 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 separation section 24 through the gas permeable membrane 23. As a result, a combustion reaction occurs between the combustible gas components (unreformed methane, unreacted hydrogen, unreacted carbon monoxide, etc.) in the second fuel electrode off-gas and oxygen via the oxidation catalyst, and carbon dioxide And steam is generated. A combustion off gas pipe P8-1 is connected to the outlet side of the combustion space 22A, and the combustion off gas is delivered from the combustion space 22A.

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

(Reformer)
The reformer 54 of the present embodiment has a multi-cylindrical shape, and has an annular vaporization flow passage 55A arranged radially outside and an inner flow passage arranged adjacent to the inside in the radial direction of the vaporization flow passage 55A. 55B. The vaporization channel 55A and the inner channel 55B are separated by a partition wall 57.

The vaporization flow channel 55A has an upper annular space filled with the reforming catalyst 58, and a lower side thereof is a spiral flow channel 55A-2 formed in a spiral shape in the cylindrical axis direction of the cylindrical shape.
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 (flow passage upstream side) of the vaporization flow passage 55A.
A fuel supply blower B1 is connected to the other end of the fuel gas pipe P1-1, and methane as a fuel gas source is supplied to the vaporization flow passage 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. An ion exchange resin 56 and a pump 27B are provided in the water supply pipe P2-2. By driving the pump 27B, the water stored in the water tank 27 is supplied to the reformer 54 through the ion exchange resin 56.

One end of the reformed gas pipe P1-2 is connected to the upper end (downstream of the flow passage) of the vaporization flow passage 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.

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

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

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

(Condenser)
A cooling water circulation flow path 26A is piped in the condenser 26, and cooling water from an exhaust heat input type absorption refrigerator 36, which will be described later, is circulated and supplied by the drive of the pump 26P and sent from the reformer 54. The combustion offgas is cooled. As a result, the water vapor in the combustion off gas is condensed. The condensed water is sent to the water tank 27 through the water pipe P9.

The combustion off-gas from which the water vapor has been separated and removed is sent to the carbon dioxide gas pipe P10. The combustion offgas from which water (liquid phase) has been removed by the condenser 26 has a high carbon dioxide concentration, and the combustion offgas 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 sent from the condenser 26. Specifically, one or more of the concentrations of combustible gases such as methane, carbon monoxide, and hydrogen, carbon dioxide, and oxygen are detected. The composition detector 44 is connected to the controller, and the composition information of the detected carbon dioxide rich gas is transmitted to the controller. 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 on the downstream side of the confluence portion where the air electrode off-gas pipes P6 from the first air electrode 12B and the second air electrode 14B are merged. In the second heat exchanger 32, heat exchange is performed between the air electrode off gas flowing through the air electrode off gas pipe P6 and the oxidant gas flowing through the oxidant gas pipe P5, the oxidant gas is heated, and the air electrode off gas is changed. To be cooled. The air electrode off gas is supplied to the exhaust heat input type absorption refrigerating machine 36 via the second heat exchanger 32.

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

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

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

The cold heat generated by the exhaust heat input type absorption refrigerating machine 36 is sent to the condenser 26 via the cooling water flowing through the cooling water circulation passage 26A, the combustion off-gas is cooled by the condenser 26, and further the combustion off-gas is cooled. Water vapor is condensed off.

The water tank 27 is connected to the cooling water circulation flow path 26A, the heat radiation circuit 37, and a heat medium flow path (not shown) through which water as a heat medium of the exhaust heat input type absorption refrigerator 36 flows. When water is insufficient in the cooling water circulation flow path 26A, the heat radiation circuit 37, and the heat medium flow path, water is appropriately replenished from the water tank 27 via a replenishment system 67 described below.
The exhaust heat input type absorption refrigerator 36 has, for example, the ability to generate cooling water at -5°C to 12°C.

(Replenishment system)
A replenishment system 67 including a pipe P11, a pump 27A and the like is connected to the water tank 27. 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 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. The pump 27A and the solenoid valve are controlled by the control unit 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, and the buffer tank has a storage amount of cooling water. A liquid level sensor (not shown) for detecting The liquid level sensor is connected to a control unit described later, and detection data of the liquid level (cooling water storage amount) is output to the control unit. Thereby, the control unit can grasp the storage amount of the cooling water in each of the cooling tower 38, the cooling water circulation passage 26A, and the liquefaction cooling water circulation passage 70A.

(Carbon dioxide gas liquefaction section)
The carbon dioxide-rich gas sent to the carbon dioxide gas pipe P10 is sent to the carbon dioxide gas liquefying unit 66 including a compressor 68, a cooling device 70, and the like.
The carbon dioxide rich gas sent to the carbon dioxide gas liquefying unit 66 is first compressed by the compressor 68. The compressor 68 is operated by a DC motor (not shown) and can compress carbon dioxide gas to 4 MPa or more. Further, the DC motor of the compressor 68 is driven by the electric power obtained by the first fuel cell stack 12 and the second fuel cell stack 14, but, for example, when the system is started, an external commercial power source is used. It is also possible to drive with electric power (surplus electric power) obtained by renewable energy power generation (not shown). Examples of renewable energy power generation include solar 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, etc. Good. The compressor 68 is not limited to the form of being driven by a DC motor, but may be of a form driven by an AC motor.

Since the DC motor of the compressor 68 can be directly driven by using the DC power obtained by 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 battery cell stack 14 converts the DC power to AC power and drives the AC motor with AC power, resulting in less energy loss and efficiency. 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. The pipe P114 is provided with a temperature sensor 74 and a pressure sensor 76, and the temperature data of carbon dioxide gas measured by the temperature sensor 74 and the pressure data of carbon dioxide gas measured by the pressure sensor 76 are controlled respectively. Sent to the department.

A liquefaction cooling water circulation passage 70A is provided in the cooling device 70, and a circulation pump 78 controlled by a controller is attached to the liquefaction cooling water circulation passage 70A. Cooling water from the exhaust heat input type absorption refrigerator 36 is circulated and supplied to the liquefying cooling water circulation path 70A to cool the compressed carbon dioxide rich gas supplied from the compressor 68 to generate liquefied carbon dioxide.

The liquefaction cooling water circulation path 70A is provided with a temperature sensor 80 that detects the temperature of the cooling water flowing into the cooling device 70. The temperature data of the cooling water measured by the temperature sensor 80 is sent to the control unit. A flow rate sensor (not shown) that measures the flow rate of the cooling water may be provided in the liquefying cooling water circulation path 70A.

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

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

In the fuel cell power generation system 10A, pumps, blowers, and other auxiliary equipment are driven by the electric power generated by the fuel cell power generation system 10A. In order to efficiently use the electric power generated by the fuel cell power generation system 10A without converting it to AC as it is, it is preferable that the auxiliary machine be driven by DC 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 the 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 via the fuel gas pipe P1-2.
From the steam pipe P2, steam for steam reforming is supplied to the first fuel electrode 12A via 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 generate hydrogen and carbon monoxide. Further, carbon dioxide and hydrogen are generated by the shift reaction between the generated 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 above-mentioned reaction occurs to generate power. The first fuel electrode off-gas is delivered from the first fuel electrode 12A of the first fuel cell stack 12 to the first fuel electrode off-gas pipe P7. Further, the air electrode off-gas is delivered from the first air electrode 12B to the air electrode off-gas pipe P6.

The first fuel electrode off-gas sent 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.
Power generation is also performed in the second fuel cell stack 14 similarly to the first fuel cell stack 12. The second fuel electrode offgas is delivered from the second fuel electrode 14A of the second fuel cell stack 14 to the second fuel electrode offgas pipe P7-2. Further, the air electrode off-gas is delivered from the second air electrode 14B to the air electrode off-gas pipe P6.

The air electrode off-gas is supplied to the exhaust heat input type absorption refrigerating machine 36 via the second heat exchanger 32. In the second heat exchanger 32, heat exchange is performed between the air electrode off-gas and the oxidant gas, and the oxidant gas is heated by the air electrode off-gas. In the exhaust heat input type absorption refrigerating machine 36, as described above, cold heat is generated by utilizing 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 film and flows through the combustion space 22A.

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

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

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

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

The vaporization flow channel 55A has a long spiral flow channel 55A-2, which is formed in a spiral shape in the cylindrical axis direction on the lower side, so that the water supplied along with the fuel gas has a long spiral flow channel 55A. -2 is sufficiently heated to become water vapor while passing through -2 over time. Then, the heated fuel gas and water vapor flow through the spiral flow path 55A-2 and then pass through the reforming catalyst 58 heated by the heat of the combustion offgas, 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 refrigerating machine 36 which is circulated and supplied through the cooling water circulation flow path 26A, and the steam 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 the water vapor has been removed by the condenser 26 becomes a 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 sends the detected information to the controller.

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

In the flow rate adjustment processing, it is determined whether or not 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 detection unit 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%, and more preferably 0.01 to 1 vol%. When the concentration of the combustible gas is higher than the threshold value G1, the flow rate adjustment valve 42 is controlled to increase the flow rate of the air electrode offgas branched to the branch air electrode 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 the 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 unit 66 and compressed, and the compressed carbon dioxide-rich gas is sent to the cooling device 70. The cooling device 70 cools the carbon dioxide rich gas compressed with the cooling water from the exhaust heat input type absorption refrigerator 36 to generate liquefied carbon dioxide.

Since the exhaust heat input type absorption refrigerating machine 36 uses the exhaust heat of the air electrode off-gas to generate cold heat, the motor drives the compressor to compress and expand the refrigerant (for example, a turbo). As compared with a case where cold energy is generated by a refrigerator or the like), cold energy (used for cooling water to be cooling water) can be efficiently generated with less electric power.

From the state diagram of carbon dioxide gas shown in FIG. 3, as an example, carbon dioxide gas compressed to 4 MPa or more liquefies if 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, the 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. Liquefied carbon dioxide is obtained by cooling with. 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)
Either the temperature of the high-pressure carbon dioxide gas that has passed through the compressor 68 (measured by the temperature sensor 74), the pressure (measured by the pressure sensor 76), or the amount of carbon dioxide gas remaining without being liquefied According to one or more measurement results, the control unit controls the temperature of the cooling water supplied to the cooling device 70 (measured by the temperature sensor 80) and the flow rate (measured by a flow rate sensor (not shown)) of the exhaust heat input type absorption. The operation of the rotary 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 liquefaction amount of the carbon dioxide gas in accordance with the temperature and pressure of the recovered carbon dioxide gas, or the amount of residual carbon dioxide gas at the time of liquefaction. It is possible to reduce the temperature of the cooling water according to this, increase the flow rate of the circulating cooling water, or use both of them together.

In the cooling device 70, liquefied carbon dioxide accumulates downward, and unliquefied carbon dioxide gas remains above the liquefied carbon dioxide. Therefore, 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 inside the cooling device 70 without being liquefied (the internal space volume of the cooling device 70 is known).

The liquefied carbon dioxide thus generated in the carbon dioxide gas liquefying unit 66 is sent to and stored in the tank 84 via the pipe P15 and the pump 82. The liquefied carbon dioxide stored in the tank 84 can also be used for commercial and industrial purposes as in the past.

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. The liquefied carbon dioxide stored in the tank 84 may be transported by the lorry 86 or the like, or by a pipeline or the like.

In the fuel cell power generation system 10A of the present embodiment, the second fuel electrode off-gas sent from the second fuel electrode 14A of the second fuel cell stack 14 is combusted in the combusting section 22, so the second fuel cell stack 14 The amount of unreacted fuel gas used for power generation in the second fuel cell stack 14 is larger than that in the case where the first fuel electrode off-gas before being used for power generation is burned. Therefore, the power generation efficiency of the second fuel cell stack 14 can be increased.

Further, in the combustion section 22, carbon dioxide and water vapor are generated by the combustion reaction between the combustible gas contained in the second fuel electrode off gas and oxygen. Therefore, it is possible to recover the high-concentration carbon dioxide by reducing the combustible gas from the second fuel electrode off-gas. Further, only the oxygen in the air electrode off gas is supplied to the combustion section 22, and the second fuel electrode off gas contains less unreacted fuel gas than the first fuel electrode off gas, resulting in carbon dioxide. Content rate is high. Therefore, it is possible to reduce the amount of unreacted fuel gas burned in the combustion unit 22 and the amount of oxygen required to burn the unreacted fuel gas.

Further, since the fuel cell power generation system 10A of the present embodiment has the branched air electrode off-gas pipe P6-2 branched from the air electrode off-gas pipe P6, the composition of the carbon dioxide rich gas detected by the composition detection unit 44. Based on the information, it is possible to easily adjust the air electrode off-gas flow rate to be branched to the branch air electrode off-gas 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 amounts of combustible gas and oxygen contained in the combustion off gas become lower than the predetermined threshold value.

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

Further, in the fuel cell power generation system 10A of the present embodiment, since the hydrogen ion conductive type solid oxide fuel cell is used for the fuel cell stack, water vapor is not generated in the first fuel electrode 12A. Therefore, the amount of water vapor contained in the first fuel electrode off-gas is reduced, so that the power generation efficiency in the second fuel cell can be improved. Further, since the amount of water vapor contained in the second fuel electrode off-gas also decreases, the amount of water vapor 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, the combustion section 22 is arranged adjacent to the gas permeable membrane 23 of the oxygen separation section 24, so that the combustion section 22 and the oxygen separation section 24 are formed integrally with each other to provide a compact oxygen permeation. The film combustor 20 can be configured.

Further, in the fuel cell power generation system 10A of the present embodiment, the heat of the air electrode off-gas is used for cold heat generation in the exhaust heat input type absorption refrigerator 36, so the first fuel cell stack 12, the second fuel cell stack 10 The exhaust heat from 14 can be effectively used. Further, since the air electrode off-gas contains a large amount of water vapor, the heat of condensation can also be effectively used by condensing the water vapor in the exhaust heat input type absorption refrigerator 36 during heat exchange.

Further, in the fuel cell power generation system 10A of the present embodiment, the control unit controls the storage amount of the cooling water in each of the buffer towers of the cooling tower 38, the cooling water circulation passage 26A, and the liquefaction cooling water circulation passage 70A from the liquid level sensor. When it is determined based on the detection data, and when it is determined that the storage amount of cooling water is less than the preset lower limit value, the solenoid valve and the pump 27A are controlled to supply the water used for cooling water to the water tank 27. Can be replenished from As described above, when the cooling water is insufficient, it is not necessary to supply the water from the external water supply or the like, and it is possible to reduce the amount of external dependence of water.

In the present embodiment, the carbon dioxide is separated from the combustion offgas by condensing and removing the water vapor in the combustion offgas with the condenser 26, but other means, for example, the carbon dioxide separation membrane separates the carbon dioxide. 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.

Further, in the oxygen-permeable membrane-equipped combustor 20 of the present embodiment, the outer side is the combustion section 22 and the inner side is the oxygen separation section 24. However, the outer side is the oxygen separation section 24 and the inner side is the combustion section 22. Good.

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

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

In the present 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 circulation gas pipe P3 is branched from the second fuel electrode off-gas pipe P7-2, and the circulation gas pipe P3 is connected to the fuel gas pipe P1. A circulating gas blower B3 is provided in the circulating gas pipe P3.

A first heat exchanger 30 is provided in the middle of the fuel gas pipe P1. A combustion offgas pipe P8 for delivering combustion offgas is connected to the outlet side of the combustion space 22A of the combustor 20 with an oxygen permeable film, and the combustion offgas pipe P8 passes through the first heat exchanger 30 and the other end. Are connected to the condenser 26. In the first heat exchanger 30, the fuel gas is heated by the 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 steam has been removed by the condenser 26 becomes a carbon dioxide rich gas having a high carbon dioxide concentration, and the carbon dioxide blower B4 causes carbon dioxide to be discharged. It is sent to the gas pipe P10 and then sent to the composition detector 44. The composition detector 44 detects the composition of the carbon dioxide-rich gas and sends the detected information to the controller.

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

(Structure of carbon manufacturing 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 powder carbon generator 178, and the like.

The water electrolyzer 170 is supplied with the water in the water tank 27 that has passed through the pipe P116, the pump 180, and the water purifier 182. The water purifier 182 purifies the water from the water tank 27 (removes foreign substances, adjusts PH, etc.). The water electrolysis device 170 can generate hydrogen gas and oxygen gas by electrolyzing water purified using the electric power obtained in the first fuel cell stack 12 and the second fuel cell stack 14. .. The water electrolysis device 170 can also electrolyze water using electric power (so-called “clean energy”) obtained by renewable energy power generation (not shown). Examples of renewable energy power generation include solar 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, etc. Good. That is, from the standpoint of reducing carbon dioxide in the atmosphere or suppressing the release of carbon dioxide to the atmosphere, the DC power obtained by the first fuel cell stack 12 and the second fuel cell stack 14 and regeneration It is preferable to use the electric power obtained by the possible energy generation.

Since the water electrolysis device 170 electrolyzes water using the DC power obtained by the first fuel cell stack 12 and the second fuel cell stack 14 or the electric power obtained by the renewable energy power generation, for example, The water can be efficiently electrolyzed as compared with the case where the AC power of the power generation device that releases carbon dioxide gas is converted to DC power and used for electrolysis. The water electrolysis device 170 is controlled by the controller.

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

(Structure of powder carbon generator)
As shown in FIG. 5, the powdered carbon generator 178 includes a temperature raising device 184, a shift reactor 186, a cooler 188, and a carbon deposition/separation unit 200.

The heating device 184 includes an outer cylinder 202, a cylindrical partition wall 204 disposed inside the outer cylinder 202, and a closing member that closes the outer cylinder 202 and the opening portion of the cylindrical partition wall 204 on the cylinder axial end side. The inside of the structure is composed of 206 and has a closed multi-cylindrical shape.

A gas combustion flow path 208 as a first flow path of the present invention is provided between the outer cylinder 202 and the partition wall 204, and an inner peripheral side of the cylindrical partition wall 204 is heated as a second flow path of the present invention. The gas combustion flow path 208 and the temperature raising unit 210 are separated by a partition wall 204.

A spiral passage forming member 212 having a spiral shape is disposed inside the gas combustion flow path 208, and is formed in a spiral shape in the cylinder axis direction of the temperature raising device 184.

In the temperature raising device 184, hydrogen gas and oxygen gas sent from the water electrolysis device 170 are supplied to the gas combustion flow path 208, carbon dioxide gas sent from the condenser 26, and hydrogen sent from the water electrolysis device 170. The gas and the gas are supplied to the temperature raising unit 210.
In the gas combustion flow path 208, hydrogen gas and oxygen gas are combusted and reacted with each other, and the heat generated by the combustion reaction causes the carbon dioxide gas and hydrogen gas passing through the temperature raising unit 210 to have a high temperature, for example, 1000 to 1200° C. Can be heated to.

A shift reactor 186 is arranged on the downstream side 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.
In the shift reactor 186, carbon dioxide gas can be shifted to carbon monoxide in a hydrogen gas atmosphere as shown in the following formula (5).
CO ₂ +H ₂ →CO+H ₂ O (5)
Here, the reaction can be promoted by using a known catalyst.

A cooler 188 is arranged on the downstream side 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 lower. The temperature is adjusted so that

The carbon deposition/separation unit 200 is disposed on the downstream side of the cooler 188, and the temperature-controlled carbon monoxide gas and steam discharged from the cooler 188 are introduced into the carbon deposition/separation unit 200. The carbon deposition separation part 200 is provided with a spiral flow path 214 formed in a spiral shape and having a long passage length.

In the carbon deposition/separation unit 200, carbon monoxide in the gas is converted into carbon and carbon dioxide by the following equation (6) in the spiral flow passage 214 having a long flow passage length.
2CO → C+CO ₂ (6)
The above equation (6) is an exothermic reaction.
Further, in the spiral flow path 214 of the carbon deposition/separation unit 200, the reaction of generating carbon and water from carbon dioxide gas and hydrogen gas according to the following expression (7) proceeds simultaneously with the reaction of the above expression (6).
CO ₂ +2H ₂ → C+2H ₂ O (7)
In the carbon deposition separation part 200, a known reduction catalyst is provided inside the spiral flow path 214 in order to promote the reaction.

In this way, in the carbon deposition/separation unit 200, carbon is deposited and immobilized.
C generated by the reduction reaction of the above formula (6) is carbon powder and can be discharged from the lower part of the spiral flow path 214. Further, H ₂ 0 generated by the reduction reaction of the above formula (6) is specifically steam, and the steam is sent to the condenser 26 via the pipe P117.

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

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

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

The water electrolysis device 170 electrolyzes the water sent from the water purification device 182 to generate hydrogen gas and oxygen gas. The generated hydrogen gas and oxygen gas are heated by the powder carbon generator 178. 184 is supplied. Further, the carbon dioxide rich gas discharged from the condenser 26 and the hydrogen gas sent from the water purifying device 182 are supplied to the temperature raising unit 210 of the temperature raising device 184.

To start the powder carbon generator 178, first, in the gas combustion flow path 208 of the temperature raising device 194, hydrogen gas and oxygen gas are reacted (combusted). When the combustion flame generated by the combustion reaction of hydrogen gas and oxygen gas and the high-heat exhaust gas (water vapor) pass through the gas combustion flow path 208, the heat of the combustion flame and the exhaust gas rises through the partition wall 204. It is transmitted to the warm part 210. The gas combustion flow passage 208 is formed in a spiral shape in the cylinder axis direction of the temperature raising device 184 and has a long flow passage length. Therefore, the combustion flame due to the above reaction and the heat of exhaust gas are taken over time. It can be sufficiently applied to the temperature raising section 210. That is, in the temperature raising device 184, the combustion flame and the residence time of the exhaust gas can be extended. 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 are reliably raised to a predetermined temperature (for example, 1000 to 1200° C.). Can be warmed. In the gas combustion flow path 208, water (water vapor) generated by the reaction between hydrogen gas and 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 a shift reactor 186, and the carbon dioxide gas is subjected to a shift reaction to carbon monoxide in a hydrogen gas atmosphere to generate carbon monoxide. And water are generated.

The carbon monoxide gas and water vapor discharged from the shift reactor 186 are sent to the cooler 188, cooled to a predetermined temperature (for example, 600° C. or lower), and then supplied to the carbon deposition separation unit 200.
In the carbon deposition separation part 200, powder 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 spiral flow path 214 can be made long, and the spiral flow path 214 can have a longer retention time. The reaction time can be taken sufficiently and powder carbon can be efficiently obtained without wasting carbon dioxide gas.
The steam for carbon deposition separation part 200 is sent to the condenser 26 via the pipe P117 and cooled in the condenser 26 to become water.

In the fuel cell power generation system 10B of the present embodiment, since the first fuel cell stack 12, the second fuel cell stack 14 and the carbon production section 166 are continuously connected and provided on-site, power is being generated. Can continuously and efficiently produce powdered carbon.
Unless carbon powder is ignited and burned, carbon powder is not released into the atmosphere as carbon dioxide gas, and the release of carbon dioxide gas into the atmosphere can be suppressed.

In addition, powdered carbon is easy to transport to the storage site, and if it is not placed under conditions where the ignition source and oxygen are uniform, landfill disposal underground or just loading it on the ground will stabilize carbon fixation for a long time. Can be realized. The produced powder carbon can also be used in commercial and industrial fields as carbon black or the like.

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

By using carbon powder such as graphite, carbon nanotubes or diamond powder, it does not burn easily even if there is an ignition source or oxygen, and it fixes carbon safely and long-term stably even if it is loaded on the ground. This makes it possible to reduce the energy loss and cost for transportation and press-fitting, because there is no restriction on the storage location. It should be noted that graphite can be used as a pencil lead, brake pads for automobiles, etc., carbon nanotubes as semiconductors and structural materials, and synthetic diamond powder can be used as industrial materials, blade materials for diamond cutters of machine tools, etc. it can.

The carbon product manufacturing apparatus 216 is also a part of the carbon manufacturing unit 166, and is provided on-site in the fuel cell power generation system 10B. Further, the product produced by using powdered carbon is not limited to the above carbon product, and a carbon material such as carbon nanohorn or fullerene may be produced by a known technique and used commercially or industrially.

In the temperature raising device 184 of the present embodiment, the gas combustion flow passage 208 has a spiral shape on the outer side and the temperature raising section 210 does not have a spiral shape on the inner side, but the gas combustion flow path has a spiral shape on the inner side. The temperature raising unit 210 may be 208 and the outside may not be spiral.

Further, in the temperature raising unit 184 of the present embodiment, the temperature raising unit 210 is not a spiral flow passage, but the temperature raising unit 210 may be a spiral flow passage.

[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 variously modified and carried out within the scope not departing from the spirit thereof. Of course,

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

10A Fuel cell power generation system 10B Fuel cell power generation system 12 First fuel cell stack (fuel cell)
12A 1st fuel electrode (fuel electrode)
12B 1st air electrode (air electrode)
14 Second fuel cell stack (fuel cell)
14A 2nd 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 (partitioning member)
29 Inner spiral passage forming member (partitioning member)
170 Water Electrolyzer 184 Heater (Reactor)
200 Carbon deposition separation part (carbon deposition part)
204 partition wall 208 gas combustion flow path (first flow path)
212 spiral passage forming member (partitioning member)
210 Temperature rising part (2nd flow path)
P6-2 Branch air electrode off-gas pipe (second introduction path)
P7-2 Second fuel electrode off-gas pipe (first introduction path)

Claims (5)

A partition wall that has a tubular shape and separates the inner first flow path from the outer second flow path;
A catalyst that is provided in at least one of the first flow path and the second flow path and that promotes a reaction between gases;
A partitioning member which is provided in at least one of the first flow path and the second flow path and has a spiral shape inside the flow path in the direction of the cylinder axis;
A reactor equipped with. The reactor according to claim 1, wherein the partition wall includes a gas permeable membrane that allows a gas used for a reaction from one of the first flow path and the second flow path to pass through the other. The reactor according to claim 2, wherein the catalyst is laminated on the gas permeable side of the gas permeable membrane. 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 generate power, and the unreacted fuel gas and first carbon dioxide gas from the fuel electrode. A fuel cell in which the fuel electrode off-gas containing is discharged, and the air electrode off-gas containing oxygen is discharged from the air electrode;
One of the first flow path and the second flow path is a reaction path provided with an oxidation catalyst as the catalyst and the partition member, the gas permeable film is an oxygen permeable film, and the first flow path is And the reaction device according to claim 3, 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 to the reaction path;
A second introduction path for introducing the air electrode off-gas into the air electrode off-gas passage,
Equipped 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 off-gas and oxygen that has permeated the oxygen permeable membrane from the first flow path. Electric power is generated by 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, carbon dioxide gas is discharged from the fuel electrode, and oxygen is contained from the air electrode. A fuel cell that emits air electrode offgas,
A water electrolysis device that electrolyzes water to generate hydrogen gas and oxygen gas,
It has a tubular shape, and has an outer first flow path and an inner second flow path that is arranged with a partition wall therebetween, and has a spiral shape in which the flow path interior is directed to the first flow path in the direction of the cylinder axis. A partitioning member is formed, and a reaction device in which the hydrogen gas and the oxygen gas are reacted in the first flow path, and the carbon dioxide gas and the hydrogen gas are supplied to the second flow path,
A carbon deposition part in 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,
And a fuel cell power generation system.