JP7181060B2 - fuel cell power generation system - Google Patents

Description

TECHNICAL FIELD The present invention relates to a fuel cell power generation system, and more particularly to a fuel cell power generation system that uses a low-temperature liquid fuel to generate power and effectively utilizes at least one of the cold energy of the low-temperature liquid fuel and the expansion energy when the low-temperature liquid fuel evaporates. Regarding the system.

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 4).

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

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. and are required.
However, when a commercial power supply, that is, an external energy is used for the compressor and the cooling device, it cannot be said that the carbon dioxide gas is efficiently liquefied. There is a risk that the amount of carbon reduction will decrease.
In addition, it is possible to decompose carbon dioxide gas to generate carbon and suppress the release of carbon dioxide gas into the atmosphere. When external energy is used, it cannot be said that carbon is produced efficiently, and carbon dioxide is emitted with the use of external energy, which may reduce the net amount of carbon dioxide reduction.
In conventional fuel cell power generation systems, it is common to supply gaseous fuel gas that has been vaporized and supplied from a low-temperature liquid fuel vaporization factory or the like. There was no technology for effectively utilizing expansion energy during vaporization for power generation in a fuel cell power generation system, separation and recovery of carbon dioxide emitted during power generation in a fuel cell power generation system, liquefaction of the recovered carbon dioxide, and powder carbon recovery.

The present invention has been made in consideration of the above facts, and uses at least one of the cold heat of the low-temperature liquid fuel and the expansion energy during vaporization of the low-temperature liquid fuel to generate power in a fuel cell power generation system or to generate power in a fuel cell power generation system. It is an object of the present invention to provide a fuel cell power generation system that can be effectively used for separating and recovering carbon dioxide that is sometimes discharged, liquefying the recovered carbon dioxide, and recovering powdered carbon.

A fuel cell power generation system according to a first aspect generates power using a liquid fuel supply section to which a low-temperature liquid fuel having a temperature of 0° C. or less is supplied, a fuel gas obtained by vaporizing the low-temperature liquid fuel, and an oxidant gas containing oxygen. , using at least one of a fuel cell that discharges off-gas containing a first carbon dioxide gas, expansion energy when the low-temperature liquid fuel is vaporized, and cold heat of the low-temperature liquid fuel, the first carbon dioxide gas and a non-gasification treatment device for non-gasification treatment.

In the fuel cell power generation system according to the first aspect , the liquid fuel supply section is supplied with a low temperature liquid fuel that retains cold heat, typically liquefied hydrogen or liquefied natural gas.
In the fuel cell, power is generated by the fuel gas obtained by vaporizing the low-temperature liquid fuel sent from the liquid fuel supply unit and the oxidant gas containing oxygen, and the off-gas containing the first carbon dioxide gas is discharged.
The non-gasification device uses at least one of expansion energy during vaporization of the low-temperature liquid fuel and cold heat of the low-temperature liquid fuel to non-gasify the first carbon dioxide gas.

The non-gasification device uses at least one of the expansion energy during vaporization of the low-temperature liquid fuel and the cold heat of the low-temperature liquid fuel to non-gasify the first carbon dioxide gas, so external energy such as a commercial power supply is not required. The first carbon dioxide gas can be efficiently non-gasified and the energy loss required for the non-gasification process can be reduced compared to the case where the first carbon dioxide gas is non-gasified using .

In addition, the non-gasification treatment in the present disclosure is a treatment to convert the gaseous first carbon dioxide gas into a form other than gaseous form, for example, compressing or cooling carbon dioxide gas to form liquefied carbon dioxide. or the process of reacting carbon dioxide to produce carbon.

A second aspect is the fuel cell power generation system according to the first aspect , wherein the non-gasification treatment device liquefies at least the first carbon dioxide gas as the non-gasification treatment.

In the fuel cell power generation system according to the second aspect , the non-gasification device liquefies at least the first carbon dioxide gas as the non-gasification treatment.
Since the first carbon dioxide gas is liquefied using at least one of the expansion energy when the low temperature liquid fuel is vaporized and the cold heat of the low temperature liquid fuel, the energy outside the system is used to liquefy the first carbon dioxide gas. Energy loss required for liquefaction can be reduced compared to the case.

A third aspect is the fuel cell power generation system according to the first aspect , wherein the non-gasification treatment device generates carbon from at least the first carbon dioxide gas as the non-gasification treatment.

In the fuel cell power generation system according to the third aspect , the non-gasification device generates carbon from at least the first carbon dioxide gas as the non-gasification treatment.
Since carbon is generated from the first carbon dioxide gas using at least one of the expansion energy when the low temperature liquid fuel is vaporized and the cold heat of the low temperature liquid fuel, energy outside the system is used to convert the first carbon dioxide gas Energy loss required for carbon production can be reduced compared to the case of producing carbon.

A fourth aspect is the fuel cell power generation system according to the second aspect or the third aspect , wherein the non-gasification treatment device cools the air with cold heat of the low-temperature liquid fuel to generate liquid air, a cryogenic separation type oxygen production device for separating oxygen from the liquid air; and the off-gas containing unburned carbon compounds discharged from the fuel electrode of the fuel cell and the said cryogenic separation type oxygen production device separated by the said cryogenic separation type oxygen production device. Oxygen is supplied, and a second carbon dioxide gas produced by causing a combustion reaction of the unburned carbon compound in the offgas with the oxygen and a combustion offgas containing the first carbon dioxide gas are discharged. and a combustion section.

In the fuel cell power generation system according to the fourth aspect , the cryogenic separation oxygen production device cools and liquefies the air with the cold heat of the low-temperature liquid fuel, and then separates the oxygen. Cryogenic separation type oxygen production equipment liquefies air using the cold heat of low-temperature liquid fuel, and then separates oxygen from the difference in boiling points between oxygen and the rest (nitrogen), so it is possible to obtain only oxygen efficiently. can be done.

In addition, the combustion unit is supplied with off-gas containing unburned carbon compounds discharged from the fuel electrode of the fuel cell and oxygen separated by the cryogenic separation type oxygen production device, and unburned carbon in the off-gas is supplied. A combustion off-gas containing the second carbon dioxide gas produced by the combustion reaction of the compound with oxygen and the first carbon dioxide gas is discharged. Combustion off-gas with a high concentration of carbon dioxide gas can be obtained by burning unburned carbon compounds discharged from the fuel electrode of the fuel cell with oxygen.

A fifth aspect is the fuel cell power generation system according to the fourth aspect , wherein the non-gasification treatment device cools the combustion off-gas, condenses moisture from the combustion off-gas, and removes moisture contained in the combustion off-gas. and a carbon dioxide gas separation unit that separates the first carbon dioxide gas and the second carbon dioxide gas.

Since the combustion off-gas contains moisture (water vapor), the first carbon dioxide gas, and the second carbon dioxide gas, when the combustion off-gas is cooled, the moisture is condensed and liquefied to form the second gas. The first carbon dioxide gas and the second carbon dioxide gas can be easily separated from the liquid water.

A sixth aspect is the fuel cell power generation system according to the fifth aspect , wherein the carbon dioxide gas separator cools the combustion off-gas with the cold heat of the low-temperature liquid fuel.

In the fuel cell power generation system according to the sixth aspect , the cold heat of the low-temperature liquid fuel is used to cool the fuel off-gas and separate the first carbon dioxide gas and the second carbon dioxide gas. Energy loss required for separating the first carbon dioxide gas and the second carbon dioxide gas can be reduced compared to cooling the combustion off-gas.

Furthermore, in the fuel cell power generation system according to the sixth aspect , there is no need to use electric power to separate the first carbon dioxide gas and the second carbon dioxide gas during power generation, so even when the commercial power supply is out of power. The separation of the first carbon dioxide gas and the second carbon dioxide gas can be continuously performed, and the power generated by the fuel cell is not used, so the first carbon dioxide gas and the second carbon dioxide gas It is possible to continue high-efficiency fuel cell power generation while separating carbon dioxide gas.

A seventh aspect is the fuel cell power generation system of the fifth or sixth aspect, which is premised on the second aspect, wherein the non-gasification treatment device is driven using expansion energy when the low-temperature liquid fuel is vaporized. a driving device for generating power; and a second driving device for compressing the first carbon dioxide gas and the second carbon dioxide gas, which are driven by the power of the driving device and discharged from the carbon dioxide gas separation unit. 1 compressor, and a cooling device for obtaining liquefied carbon dioxide by cooling the first carbon dioxide gas and the second carbon dioxide gas compressed by the first compressor using the cold heat of the low-temperature liquid fuel. and have.

In the fuel cell power generation system according to the seventh aspect , the driving device is driven using expansion energy when the low-temperature liquid fuel is vaporized to generate power for driving the first compressor.
The first compressor is driven by receiving power from the driving device, and compresses the first carbon dioxide gas and the second carbon dioxide gas discharged from the carbon dioxide gas separation section.
The cooling device uses cold heat of the low-temperature liquid fuel to cool the first carbon dioxide gas and the second carbon dioxide gas compressed by the first compressor to obtain liquefied carbon dioxide.

In the fuel cell power generation system according to the seventh aspect , the first compressor that compresses the first carbon dioxide gas and the second carbon dioxide gas is driven using expansion energy when the low temperature liquid fuel is vaporized. energy required for compressing the first carbon dioxide gas and the second carbon dioxide gas carbon dioxide gas compared to the case where the first compressor is driven using electric power outside the system Reduce losses.

Furthermore, in the fuel cell power generation system according to the seventh aspect , there is no need to use power outside the system for compressing the first carbon dioxide gas and the second carbon dioxide gas during power generation. Compression of the first carbon dioxide gas and the second carbon dioxide gas can be continued even during a power failure, and the power generated by the fuel cell is not used, so the first carbon dioxide gas, And while compressing the second carbon dioxide gas, highly efficient fuel cell power generation can be continued.

An eighth aspect is the fuel cell power generation system of the fifth or sixth aspect, which is premised on the second aspect, wherein the non-gasification treatment device is driven using expansion energy when the low-temperature liquid fuel is vaporized. a drive device that generates power, a generator that is driven by the power of the drive device and generates power, an electric motor that is driven by the power generated by the generator, and an electric motor that is driven by the electric motor , a second compressor for compressing the first carbon dioxide gas and the second carbon dioxide gas discharged from the carbon dioxide gas separation unit, and the first compressor using cold heat of the low temperature liquid fuel and a cooling device for obtaining liquefied carbon dioxide by cooling the first carbon dioxide gas and the second carbon dioxide gas compressed with.

In the fuel cell power generation system according to the eighth aspect , the driving device is driven using expansion energy when the low-temperature liquid fuel is vaporized to generate power for driving the generator.
The generator is powered by the driving device and driven to generate electric power.
The electric motor is driven by the power generated by the generator to generate power to drive the second compressor.
The second compressor is driven by receiving power from the electric motor, and compresses the first carbon dioxide gas and the second carbon dioxide gas discharged from the carbon dioxide gas separation section.
The cooling device cools the first carbon dioxide gas and the second carbon dioxide gas compressed by the second compressor using cold heat of the low-temperature liquid fuel to obtain liquefied carbon dioxide.

In the fuel cell power generation system according to the eighth aspect , the expansion energy generated when the low-temperature liquid fuel is vaporized is used to drive the driving device, the driving device drives the generator, and the electric power generated by the generator The electric motor is driven, and the electric motor drives the second compressor that compresses the first carbon dioxide gas and the second carbon dioxide gas, so when the electric motor is driven using electric power outside the system In comparison, the energy loss required for compressing the first carbon dioxide gas and the second carbon dioxide gas can be reduced.

Furthermore, in the fuel cell power generation system according to the eighth aspect , there is no need to use electric power outside the system for compressing the first carbon dioxide gas and the second carbon dioxide gas during power generation. Compression of the first carbon dioxide gas and the second carbon dioxide gas can be continued even during a power failure, and the power generated by the fuel cell is not used, so the first carbon dioxide gas, And while compressing the second carbon dioxide gas, highly efficient fuel cell power generation can be continued.

A ninth aspect is the fuel cell power generation system according to the fourth aspect , wherein the non-gasification device is driven using expansion energy when the low-temperature liquid fuel is vaporized to generate power. a generator that is driven by the power of the driving device to generate electric power; a water electrolyzer that uses the electric power generated by the generator to electrolyze water to generate hydrogen gas; and a carbon generator for generating carbon by reacting carbon dioxide gas, and the second carbon dioxide gas and the hydrogen gas in a catalytic state.

In the fuel cell power generation system according to the ninth aspect , the driving device is driven using expansion energy when the low-temperature liquid fuel is vaporized to generate power for driving the generator.
The generator is powered by the driving device and driven to generate electric power.
A water electrolyzer electrolyzes water using power generated by a generator to generate hydrogen gas.
The carbon generator causes the first carbon dioxide gas, the second carbon dioxide gas, and the hydrogen gas to react on a catalyst to generate carbon.

In the fuel cell power generation system according to the ninth aspect , the expansion energy generated when the low-temperature liquid fuel is vaporized is used to drive the driving device, the driving device drives the generator, and the electric power generated by the generator Since the water electrolyzer is driven, energy loss required for water electrolysis can be reduced compared to the case where the water electrolyzer is driven using power outside the system.

Furthermore, in the fuel cell power generation system according to the ninth aspect , since there is no need to use power outside the system for water electrolysis during power generation, water electrolysis can be continued even during a power outage such as a commercial power supply failure. Moreover, since the power generated by the fuel cell is not used, highly efficient fuel cell power generation can be continued while electrolyzing water.

In addition, since the carbon generated in the carbon generation unit is not released into the atmosphere as carbon dioxide gas unless it is ignited and burned, it is possible to suppress the release of carbon dioxide gas into the atmosphere. , long-term stable carbon fixation becomes possible.

A tenth aspect is the fuel cell power generation system according to the fifth aspect , wherein the non-gasification device is driven using expansion energy when the low-temperature liquid fuel is vaporized, and a driving device that generates power. , a generator driven by the motive power of the drive device to generate electric power, an electric centrifugal chiller driven by using the electric power generated by the generator, and using the electric power generated by the generator A water electrolysis device that electrolyzes water to generate hydrogen gas, and a carbon generation that generates carbon by reacting the first carbon dioxide gas, the second carbon dioxide gas, and the hydrogen gas on a catalyst. and a section, wherein the carbon dioxide gas separation section cools combustion off-gas discharged from the combustion section with cold heat generated by the electric turbo chiller.

In the fuel cell power generation system according to the tenth aspect , the driving device is driven using expansion energy when the low-temperature liquid fuel is vaporized to generate power.
The generator is driven by power in the drive to produce electrical power.
An electric centrifugal chiller is driven using electrical power generated by a generator to produce cold heat.
A water electrolyzer electrolyzes water using power generated by a generator to generate hydrogen gas.
The carbon dioxide gas separation unit cools the combustion off-gas discharged from the combustion unit with cold heat generated by the electric turbo chiller, condenses moisture, and separates the first carbon dioxide gas and the second carbon dioxide gas. do.
In addition, the carbon generation unit reacts the first carbon dioxide gas and the second carbon dioxide gas with the hydrogen gas on the catalyst to generate carbon and water vapor.

In the fuel cell power generation system according to the tenth aspect , the expansion energy generated when the low-temperature liquid fuel is vaporized is used to drive the driving device, the driving device drives the generator, and the electric power generated by the generator Since the electric turbo-chiller is driven, the energy loss required for cold heat generation can be reduced compared to the case where the electric turbo-chiller is driven using electric power outside the system.
Since the electric centrifugal chiller generally has high cooling efficiency, even if the power generated by the generator is used, the fuel cell power generation system can be operated with high efficiency.

Furthermore, in the fuel cell power generation system according to the tenth aspect , the expansion energy generated when the low-temperature liquid fuel is vaporized is used to drive the driving device, the driving device drives the generator, and the Since the water electrolyzer is driven by electric power, the energy loss required for water electrolysis can be reduced compared to the case where the water electrolyzer is driven by electric power outside the system.

An eleventh aspect is the fuel cell power generation system according to any one of the first aspect to the tenth aspect , which is driven using the expansion energy when the low-temperature liquid fuel is vaporized to generate the oxidant gas. An oxidant gas compression device is provided for compressing the oxidant gas to a pressure exceeding atmospheric pressure and supplying it to the fuel cell. and the fuel cell that generates power by being supplied with a high-pressure fuel gas having a pressure higher than the atmospheric pressure after being vaporized and expanded.

In the fuel cell power generation system according to the eleventh aspect , the expansion energy generated when the low-temperature liquid fuel is vaporized is used to drive the oxidant gas compressor, and the pressure above atmospheric pressure generated by the oxidant gas compressor and The fuel cell is driven in a pressurized environment by the oxidant gas and the high-pressure fuel gas generated by vaporizing the low-temperature liquid fuel and having a pressure exceeding the atmospheric pressure. Compared to a fuel cell power generation system driven by a fuel cell, the power generation performance of the fuel cell can be improved and the power generation operation can be performed, and the power generation output and efficiency can be improved. can be reduced.

Further, in the fuel cell power generation system according to the eleventh aspect , the expansion energy generated when the low-temperature liquid fuel is vaporized is used to drive the oxidant gas compression device, and the fuel cell is driven by the high pressure generated by the oxidant gas compression device. oxidant gas and high-pressure fuel gas generated by vaporizing low-temperature liquid fuel, it is possible to continue high-efficiency fuel cell power generation under a pressurized environment even in the event of a power failure such as a commercial power supply. can be done.

According to the fuel cell power generation system of the present invention, it is possible to effectively utilize at least one of the cold energy of the low-temperature liquid fuel and the expansion energy of the low-temperature liquid fuel when it is vaporized.

1 is a schematic diagram of a fuel cell power generation system according to a first embodiment; FIG. 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. 3 is a schematic diagram of a fuel cell power generation system according to a third embodiment; FIG. 4 is a schematic diagram of a fuel cell power generation system according to a fourth 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 as an example of the fuel cell power generation system of the present invention. The fuel cell power generation system 10A mainly includes a first fuel cell stack 12, a second fuel cell stack 14, an oxygen production device 16, an oxygen burner 18, a condenser 20, a water tank 22, and a carbon dioxide gas liquefier. A part 24, a tank 26, etc. are provided on-site (surrounded by a two-dot chain line).

The first fuel cell stack 12 of the present embodiment is a proton-conducting solid oxide fuel cell (PCFC: Proton Ceramic Solid Oxide Fuel Cell). It has a stacked first fuel electrode 12A and a first air electrode 12B.

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 air electrode 14A corresponding to the first air electrode 12B. It has a pole 14B and an electrolyte layer 14C corresponding to the electrolyte layer 12C.
Details of the first fuel cell stack 12 and the second fuel cell stack 14 will be described later.

The oxygen production apparatus 16 of this embodiment is a so-called cryogenic separation type oxygen production apparatus, and is of a type that separates oxygen from air. As the cryogenic separation type oxygen production apparatus, one having a known configuration can be used. The oxygen production device 16 of the present embodiment is supplied with air (atmosphere) and low-temperature liquid fuel (LF) used for cooling the air. Electric power generated by the first fuel cell stack 12 and the second fuel cell stack 14 can be used to drive the oxygen production device 16 .

The oxygen production device 16 includes an oxidant gas pipe P1 to which air is supplied, a liquid fuel pipe P2 to which a low-temperature liquid fuel is supplied, and a fuel gas (GF) obtained by vaporizing the low-temperature liquid fuel through the first fuel cell stack. 12 is connected to a pipe P12 for feeding to the first fuel electrode 12A. In addition, the tip of the pipe P12 is connected to the middle of the pipe P8, which will be described later.

Examples of low-temperature liquid fuels include fuels that are gaseous under atmospheric pressure and are compressed to low-temperature liquids, more specifically, low-temperature LNG (liquefied natural gas) and/or LH ₂ (liquefied hydrogen). Although it can be used, it is not particularly limited as long as it releases cold heat and expansion energy when vaporized and can generate hydrogen by reforming.
Here, the "low temperature" of the "low temperature liquid fuel" means at least 0°C or lower.

Oxygen produced by the oxygen production device 16 is supplied to the oxygen burner 18 through the pipe P3. Further, the oxygen burner 18 is supplied with the second fuel electrode off-gas discharged from the second fuel electrode 14A of the second fuel cell stack 14 via the second fuel electrode off-gas pipe P4.
In the oxygen combustor 18, the second anode off-gas is combusted with oxygen, and combustion gas containing carbon dioxide and water vapor is discharged. Combustion gas is supplied to the condenser 20 via the pipe P5.

A pipe P6 connected to a cooling device 32, which will be described later, is connected in the middle of the pipe P2 connected to the oxygen production device 16, and the low-temperature liquid fuel is supplied to the condenser 20 in the middle of the pipe P6. A pipe P7 is connected.

The middle part of the pipe P7 passes through the inside of the condenser 20, and the tip of the pipe P7 is a pipe for sending the fuel gas discharged from the driving device 28, which will be described later, to the first fuel electrode 12A of the first fuel cell stack 12. It is connected in the middle of P8.

In the condenser 20, the combustion off-gas supplied through the pipe P5 is cooled by cold heat of the low-temperature liquid fuel passing through the pipe P7, thereby condensing water vapor in the combustion off-gas. The condensed water is sent to the water tank 22 through the pipe P9.

The combustion off-gas from which water (liquid phase) has been removed by the condenser 20 is a gas with a high carbon dioxide concentration, and the combustion off-gas can be referred to as a carbon dioxide-rich gas. The carbon dioxide gas discharged from the condenser 20 is sent to the carbon dioxide gas liquefying section 24 via the pipe P10.

Further, in the condenser 20, the low-temperature liquid fuel (LF) passing through the pipe P7 is heated by the combustion off-gas to be vaporized into a fuel gas (GF: gaseous fuel), and then through the pipe P6 to the first fuel cell. delivered to the first anode 12A of the stack 12

(Configuration of carbon dioxide gas liquefaction unit)
The carbon dioxide gas liquefying unit 24 is provided with a driving device 28, a compressor 30 as a first compressor driven by the driving device 28, and a cooling device 32 for cooling the carbon dioxide gas. there is

The carbon dioxide gas sent to the carbon dioxide gas liquefying unit 24 is compressed by the compressor 30, and the compressed carbon dioxide gas is sent to the cooling device 32 through the pipe P11.

The drive device 28 of the present embodiment that drives the compressor 30 is a device that is supplied with high-pressure gas and converts expansion energy when the high-pressure gas expands into rotational energy (rotational driving force). The drive device 28 of this embodiment has an expansion turbine that rotates with the expansion energy generated when the high-pressure fuel gas expands. For example, other types of drive devices such as piston type air motors, rotary vane type air motors, etc. can be used instead of expansion turbines.

In addition, the compressor 30 may be any one capable of compressing gas, and is a machine that compresses gas by rotating motion of an impeller or rotor, or reciprocating motion of a piston, such as a rotary compressor, scroll compressor, screw compressor. , a reciprocating compressor, etc. can be used.

The cooling device 32 exchanges heat between the carbon dioxide gas, which has been compressed by the compressor 30 to a pressure higher than the atmospheric pressure and whose temperature has increased, and the low-temperature liquid fuel. The carbon dioxide gas supplied to the cooling device 32 is cooled by the cold heat of the low-temperature liquid fuel and becomes liquefied carbon dioxide, and the low-temperature liquid fuel is heated by the carbon dioxide gas whose temperature has risen and is gasified to become a fuel with a pressure higher than the atmospheric pressure. becomes gas.

The high-pressure fuel gas generated in the cooling device 32 in this manner is supplied to the driving device 28, and the expansion energy generated when the high-pressure fuel gas expands rotates the expansion turbine of the driving device 28, thereby causing the compressor 30 to operate. driven.

After driving the driving device 28, the fuel gas is sent to the first fuel electrode 12A of the first fuel cell stack 12 through the pipe P8.
The liquefied carbon dioxide produced by the cooling device 32 is sent to the tank 26 via the pipe P11 and the pump 34 and stored therein.

(Configuration of fuel cell)
Fuel gas is supplied to the first fuel electrode 12A of the first fuel cell stack 12 through a pipe P8. A water vapor pipe (not shown) is connected to the pipe P8, and water vapor is appropriately supplied from a water vapor source (not shown) at the time of starting or stopping.

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 equation (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 P13. Air is introduced into the oxidizing gas pipe P13 by an oxidizing gas blower (not shown).

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 P14 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 P14, and sent to the second cathode 14B of the second fuel cell stack 14.

One end of the first fuel electrode off-gas pipe P15 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 P15 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 P15. 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 the second fuel electrode off-gas pipe P4 is connected to the second fuel electrode 14A of the second fuel cell stack 14, and the second fuel electrode off-gas is sent to the oxygen burner 18 from the second fuel electrode 14A. be done.

In the second fuel cell stack 14, the same power generation reaction as in the first fuel cell stack 12 occurs, and the air electrode offgas is discharged from the second air electrode 14B to the outside of the system (atmosphere) through the air electrode offgas pipe P16. Ejected.

(action, effect)
Next, the operation of the fuel cell power generation system 10A of this embodiment will be described.
When the low temperature liquid fuel and air are supplied to the fuel cell power generation system 10A, the air is supplied to the oxygen production device 16 through the oxidant gas pipe P1, and the low temperature liquid fuel is supplied to the oxygen production device 16, the condenser 20 and It is sent to the cooling device 32 of the carbon dioxide gas liquefying unit 24 .

In the oxygen production device 16, after the air is cooled by the cold heat of the low-temperature liquid fuel, oxygen (gas) is separated and sent to the oxygen burner 18 via the pipe P3. Gases other than oxygen (nitrogen, etc.) are discharged to the outside (atmosphere). The low-temperature liquid fuel cools the air in the oxy-combustor 18, becomes gaseous fuel gas, and is sent to the first fuel electrode 12A of the first fuel cell stack 12 via the pipe P12. The fuel gas after passing through the condenser 20 and the fuel gas after passing through the compressor 30 also flow into the pipe P12 on the downstream side.

This oxygen production device 16 is a cryogenic separation type oxygen production device, is driven by electric power generated by the first fuel cell stack 12 and the second fuel cell stack 14, and uses the cold heat of the low-temperature liquid fuel. After the air is liquefied, the oxygen is separated, so the oxygen can be obtained efficiently. In addition, since the oxygen production device 16 can be operated without using external power, the energy loss required for oxygen production can be reduced, and oxygen can be produced continuously even during power outages such as commercial power supply.

Fuel gas is supplied to the first fuel electrode 12A of the first fuel cell stack 12 through the pipe P12, and oxidant gas (air) is supplied to the first air electrode 12B through the oxidant gas pipe P13. Thus, power is generated in the first fuel cell stack 12 .

In the second fuel cell stack 14, the first fuel electrode off-gas discharged from the first fuel electrode 12A of the first fuel cell stack 12 is supplied to the second fuel electrode 14A of the second fuel cell stack 14, The first air electrode off-gas discharged from the first air electrode 12B of the first fuel cell stack 12 is supplied to the second air electrode 14B of the second fuel cell stack 14 to generate power.

The cathode off-gas generated at the second cathode 14B is discharged to the outside of the system (atmosphere) through the cathode off-gas pipe P16.
On the other hand, the second fuel electrode off-gas (including unburned carbon compounds and carbon dioxide gas (first carbon dioxide gas of the present invention)) discharged from the second fuel electrode 14A is discharged from the second fuel electrode off-gas pipe P4. and the unburned carbon compounds in the second fuel electrode off-gas are burned with oxygen to produce carbon dioxide gas (second carbon dioxide gas of the present invention).

As a result, from the oxygen burner 18, the carbon dioxide gas (first carbon dioxide gas) generated along with the power generation of the first fuel cell stack 12 and the second fuel cell stack 14, and the second fuel A combustion gas containing water vapor and carbon dioxide gas (second carbon dioxide gas) produced by burning unburned carbon compounds in the pole off-gas with oxygen is discharged. This combustion gas is supplied to the condenser 20 via the pipe P5.

Note that the carbon dioxide gas (first carbon dioxide gas) generated with the power generation of the first fuel cell stack 12 and the second fuel cell stack 14 discharged from the oxygen burner 18 and the air electrode off-gas A mixture of the carbon dioxide gas (second carbon dioxide gas) produced by burning the unburned carbon compound inside with oxygen is hereinafter simply referred to as carbon dioxide gas.

In the condenser 20, the combustion off-gas is cooled by the cold heat of the low-temperature liquid fuel, water vapor in the combustion off-gas is condensed, and the condensed water is sent to the water tank 22 through the pipe P9. In the condenser 20, the combustion off-gas from which water (liquid phase) has been removed becomes a gas with a high carbon dioxide concentration and is sent to the compressor 30 of the carbon dioxide gas liquefying section 24 via the pipe P10.

Also, in the condenser 20, the low-temperature liquid fuel passing through the pipe P7 is heated by the combustion off-gas to be vaporized into a fuel gas, and is sent to the first fuel electrode 12A of the first fuel cell stack 12 via the pipe P6. sent out.

As described above, in the condenser 20 of the present embodiment, the cold heat of the low-temperature liquid fuel is used to condense the water vapor in the combustion off-gas and separate the moisture and the carbon dioxide gas. Since cold heat generated by an electric refrigerator or the like using electric power is not used, energy loss can be reduced, and separation of water and carbon dioxide gas can be continued even in the event of a power failure of a commercial power supply or the like.

The carbon dioxide gas discharged from the condenser 20 is sent to the compressor 30 of the carbon dioxide gas liquefying unit 24 via the pipe P10 and compressed, and the high pressure carbon dioxide gas is sent to the cooling device via the pipe P11. 32.

In the cooling device 32, the high-pressure carbon dioxide gas (CO ₂ ) is cooled by the cold heat of the low-temperature liquid fuel (LF) to become liquefied carbon dioxide (LCO ₂ ), and the low-temperature liquid fuel is compressed and raised in temperature. It is heated by carbon dioxide gas and vaporized to become high-pressure fuel gas (GF). The high pressure fuel gas thus generated is delivered to the drive device 28 . The drive device 28 converts the expansion energy of the high-pressure fuel gas into rotational energy to drive the compressor 30 .

As described above, the compressor 30 of this embodiment is driven by the driving device 28 that converts the expansion energy of the high-pressure fuel gas into rotational energy (rotation driving force). The energy loss is less than in the case of driving with an electric motor or the like using the electric power of 1, and the compression of carbon dioxide gas can be continued even when the commercial power supply is cut off.

In the cooling device 32, as shown in the state diagram of carbon dioxide in FIG. 2, the carbon dioxide gas is compressed so that the pressure and temperature are in the region described as liquid surrounded by the boiling line and the melting line. By cooling together, the carbon dioxide gas can be liquefied into liquefied carbon dioxide.

The liquefied carbon dioxide generated in the carbon dioxide gas liquefying unit 24 is sent to the tank 26 via the pipe P11 and the pump 34 and stored therein. Note that the liquefied carbon dioxide stored in the tank 26 can also be used for commercial and industrial purposes as before.

Since the fuel cell power generation system 10A of the present embodiment is installed on-site, liquefied carbon dioxide can be efficiently produced continuously and stored in the tank 26 during power generation. Note that the liquefied carbon dioxide stored in the tank 26 may be transported by a lorry 36 or the like, or may be transported by a pipeline or the like.

Although not shown, the pipe P6 between the cooling device 32 and the driving device 28 is provided with a flow control valve, a pressure control valve, a pressure sensor, a flow sensor, etc., and the fuel gas sent to the driving device 28 is controlled. Based on the information from the pressure sensor and the flow rate sensor, the control device can control the flow control valve and the pressure control valve to adjust the rotational speed of the driving device 28 .

As described above, according to the fuel cell power generation system 10A of the present embodiment, the cold heat of the low-temperature liquid fuel and the expansion energy during vaporization of the low-temperature liquid fuel can be effectively utilized in an environment where the low-temperature liquid fuel can be used. can be done.

[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.

As shown in FIG. 3, the fuel cell power generation system 10B of this embodiment differs from the fuel cell power generation system 10A of the first embodiment in the configuration of the carbon dioxide gas liquefying section 24. As shown in FIG.
In the carbon dioxide gas liquefying unit 24 of the present embodiment, the driving device 28 drives the generator 38, the electric power generated by the generator 38 drives the electric motor 40, and the driving force of the electric motor 40 drives the second compressor. It is configured to drive the compressor 30 as.

As described above, the compressor 30 of the present embodiment is not driven by an electric motor or the like using power outside the system such as a commercial power supply, as in the first embodiment, so that power outside the system such as a commercial power supply is used. The energy loss is less than in the case of driving with an electric motor or the like, and the compression of carbon dioxide gas can be continued even in the event of a power failure of the commercial power supply.
In addition, in this embodiment, the oxygen production device 16 can also be driven by the electric power generated by the generator 38 .
Other actions and effects are the same as those of the first embodiment.

[Third embodiment]
Next, a fuel cell power generation system 10C according to a third embodiment of the invention will be described with reference to FIG. The fuel cell power generation system 10C of the present embodiment generates power and produces carbon powder to suppress the release of carbon dioxide gas generated by the power generation into the atmosphere. In addition, the same code|symbol is attached|subjected about the part similar to 1st Embodiment and 2nd Embodiment, and detailed description is abbreviate|omitted.

As shown in FIG. 4, in the fuel cell power generation system 10C of this embodiment, part of the supplied low-temperature liquid fuel is delivered to the evaporator 42 through a pipe P17 connected in the middle of the pipe P2. In the evaporator 42, the low-temperature liquid fuel is vaporized (evaporated) by the heat of air (atmosphere) to become fuel gas. The evaporator 42 is supplied with heat generated inside the system, such as the heat of the air electrode offgas discharged from the second air electrode 14B of the second fuel cell stack 14, the heat of the oxygen burner 18, etc. It may promote vaporization of the fuel.

The fuel gas discharged from the evaporator 42 is sent to the driving device 28 through the pipe P18 to drive the driving device 28. As shown in FIG. The fuel gas after driving the driving device 28 is sent to the first fuel electrode 12A of the first fuel cell stack 12 through the pipe P19.

The driving device 28 of the present embodiment drives the generator 38, and the electric power generated by the generator 38 is used for the electric turbo chiller 44 and the water electrolysis device 48 of the carbon production unit 46, which will be described later.

A cooling water circulation passage 20A for circulating cooling water between the condenser 20 of the present embodiment and the electric turbo chiller 44 is piped. Cooling water is circulated and supplied by driving a pump (not shown).

In the condenser 20 of this embodiment, the combustion off-gas is cooled by the cold heat of the cooling water generated by the electric turbo chiller 44 . Part of the water condensed in the condenser 20 is sent to the water tank 22 via the water pipe P9, and part of the water in the water tank 22 is transferred via the water pipe P20 to the water electrolyzer of the carbon production unit 46, which will be described later. 48.

(Carbon Production Department)
The carbon production section 46 includes a water electrolysis device 48, a pipe P21, a hydrogen blower 50, a pipe P22, an oxygen blower 52, an oxygen tank 54, a powdered carbon generator 56, and the like.

Water in the water tank 22 is supplied to the water electrolysis device 48 through a water pipe P20, a pump 58, and a water purification device 60. As shown in FIG. The water purification device 60 purifies the water from the water tank 22 (removes foreign matter, adjusts pH, etc.). The water electrolysis device 48 can convert the AC power obtained by the generator 38 into DC power and electrolyze water to produce hydrogen gas and oxygen gas.

Hydrogen gas generated by the water electrolysis device 48 is sent to the powdered carbon generator 56 via the pipe P21 and the hydrogen blower 50, oxygen gas is sent to the oxygen tank 54 via the pipe P22 and the oxygen blower 52, It is stored in the oxygen tank 54 .
The hydrogen blower 50 and the oxygen blower 52 can be driven by the AC power obtained by the generator 38, but the power generated by the first fuel cell stack 12 and the second fuel cell stack 14 can be driven by

As an example, the powdered carbon generator 56 has a multi-cylindrical shape, and includes a gas channel 56A having an annular shape in a plan view, and a carbon fixing portion 56B arranged radially inside the gas channel 56A. have.
Carbon dioxide gas sent from the condenser 20 through the pipe P24 and hydrogen gas sent from the water electrolysis device 48 are supplied to the carbon fixing section 56B. In the carbon fixing section 56B, the carbon dioxide gas and the hydrogen gas are caused to undergo a reduction reaction such as the following formula (5) using a catalyst.
_CO2 + _2H2- >C+ _2H2O (5)

The C produced by the reduction reaction is powdered carbon and can be discharged from the lower portion of the carbon fixing portion 56B. Further, the H ₂ O generated in the reduction reaction is specifically water vapor, and the water vapor is sent to the condenser 20 via the pipe P23.

(action, effect)
Next, the operation of the fuel cell power generation system 10C of this embodiment will be described.
In this embodiment, the cold heat generated by the electric turbo chiller 44 is used instead of the cold heat of the low-temperature liquid fuel to be applied to the condenser 20. However, the electric turbo chiller 44 generally has high cooling efficiency. Therefore, even if the electric power generated by the generator 38 is used, the fuel cell power generation system 10C can be operated with high efficiency.

In the fuel cell power generation system 10C of the present embodiment, the water electrolysis device 48 converts AC power obtained by the generator 38 driven by the drive device 28 driven by the expansion energy of the fuel gas into DC power to generate water. is electrolyzed, the energy loss is less than when water is electrolyzed using power outside the system such as a commercial power supply, and water can be electrolyzed continuously even during a power failure of the commercial power supply. be able to.

The water electrolysis device 48 can also electrolyze water using power (so-called “clean energy”) obtained by renewable energy generation (not shown) that does not emit carbon dioxide gas into the atmosphere. 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.

In the carbon fixing section 56B, the carbon dioxide gas sent from the condenser 20 and the hydrogen gas sent from the water electrolysis device 48 are supplied, and a reduction reaction such as the formula (5) occurs. In order to initiate the above reaction, it is necessary to raise the ambient temperature to a high temperature. However, since heat is generated by the reaction, it is not necessary to apply heat from the outside once the reaction has started. When starting the powdered carbon generator 56, first, hydrogen gas and oxygen gas are supplied to the gas flow path 56A and ignited. After ignition, if heat is generated by the reaction of the formula (5), the supply of oxygen gas and hydrogen gas is stopped.

In the carbon fixing section 56B, by continuously supplying carbon dioxide gas and hydrogen gas, it is possible to continuously generate powdered carbon (“C” in the above formula (5)). The produced powdered carbon can be taken out from below the carbon fixing portion 56B. Also, the water vapor (H ₂ O in the formula (5)) generated by the reaction of the carbon dioxide gas and the hydrogen gas is discharged from below the carbon fixation portion 56B. Note that the water vapor discharged from the carbon fixing section 56B is sent to the condenser 20 through the pipe P25 and cooled by the condenser 20 to become water.
The water generated by the condenser 20 and stored in the water tank 22 can be used to replenish the cooling water in the cooling water circulation flow path 20A.

Since the fuel cell power generation system 10C of the present embodiment is provided on-site, powdered carbon can be produced continuously and efficiently during power generation.
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 10C of the present embodiment, powdered carbon is produced from carbon dioxide gas, but a carbon product manufacturing device 62 that converts the powdered carbon into graphite, carbon nanotubes, diamond, or the like may be further added. In the carbon product manufacturing apparatus 62, 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 10C 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 10C, 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 62 is also a part of the carbon manufacturing section 46, and is provided on-site in the fuel cell power generation system 10C. 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.

As described above, according to the fuel cell power generation system 10B of the present embodiment, it is possible to effectively utilize the expansion energy during vaporization of the low temperature liquid fuel in an environment where the low temperature liquid fuel can be used.

[Fourth embodiment]
Next, a fuel cell power generation system 10D according to a fourth embodiment of the invention will be described with reference to FIG. In the fuel cell power generation system 10D of this embodiment, in order to improve the output and efficiency of the power generation system, the expansion energy generated when the low-temperature liquid fuel is vaporized is used to drive the compressor, and the oxidizing gas supplied to the fuel cell power generation system is supplied to the fuel cell power generation system. The oxidant gas is compressed to generate a high-pressure compressed oxidant gas having a pressure exceeding the atmospheric pressure, and the compressed oxidant gas is supplied as the oxidant gas for the fuel cell power generation system, and at the time of vaporization of the low-temperature liquid fuel The first fuel cell stack 12 and the second fuel cell stack 14 are operated in a pressurized environment by supplying the generated fuel gas having a pressure higher than the atmospheric pressure as the fuel gas. It improves the output and efficiency of the cell stack 12 and the second fuel cell stack 14 . In addition, the same code|symbol is attached|subjected about the part similar to 1st Embodiment, 2nd Embodiment, and 3rd Embodiment, and detailed description is abbreviate|omitted.

As shown in FIG. 5, the fuel cell power generation system 10D of the present embodiment includes a driving device 63 driven by high-pressure fuel gas that has passed through the cooling device 32 and is above atmospheric pressure, and a compressor 65 driven by the driving device 63. It has The driving device 63 and the compressor 65 constitute the oxidant gas compression device of the present invention.

The high-pressure fuel gas that has passed through the cooling device 32 is sent to the driving device 63 through the pipe P37 to drive the driving device 63 . The fuel gas discharged from the driving device 63 by driving the driving device 63 is sent to the pipe P8 via the pipe P38.

The compressor 65 driven by the driving device 63 is provided in the middle portion of the oxidizing gas pipe P13, and compresses the supplied oxidizing gas (air) to produce a compressed oxidizing gas having a pressure higher than the atmospheric pressure. It can be supplied to the first air electrode 12B of the first fuel cell stack 12 .

In addition, it is preferable that it is the pressure exceeding 0.1 MPa with "higher pressure than atmospheric pressure" here.
Further, the first fuel cell stack 12 and the second fuel cell stack 14 used in the fuel cell power generation system 10D of the present embodiment are pressurized to a pressure exceeding 0.1 MPa, and the oxidant gas and the fuel gas are It is generally called a pressurized fuel cell.

(action, effect)
Next, the operation of the fuel cell power generation system 10D of this embodiment will be described.
In this embodiment, the compressed oxidant gas to be supplied to the fuel cell power generation system does not use a compression device that is driven by electric power outside the system such as a commercial power supply, but uses the expansion energy when the low temperature fuel is vaporized. The first fuel cell cell stack 12 and the second fuel cell, which are pressure-driven fuel cells capable of generating electricity with high efficiency, use the oxidant gas compression device, that is, the drive device 63 and the compressor 65. The cell stack 14 can be efficiently implemented without using external power. Note that the first fuel cell stack 12 and the second fuel cell stack 14 are a high-pressure compressed oxidant gas pressurized to a pressure exceeding 0.1 MPa and a By supplying the high-pressure fuel gas, it is possible to increase the amount of power generation compared to the case of supplying the normal-pressure oxidant gas and the normal-pressure fuel gas.

Further, in the fuel cell power generation system 10D of the present embodiment, the oxidant gas for pressurizing the first fuel cell stack 12 and the second fuel cell stack 14 is driven by the expansion energy of the fuel gas. Compressed oxidant gas obtained by the drive device 63 and compressor 65 is used, and the fuel gas also uses the high-pressure fuel gas generated when the low-temperature liquid fuel is vaporized, so it can continue even when the commercial power supply is cut off. Therefore, fuel cell power generation can be performed in an efficient pressurized environment.

[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

In the above embodiment, the carbon dioxide gas generated by power generation is effectively used as liquefied carbon dioxide, and the release of carbon dioxide gas into the atmosphere as carbon is suppressed. A treatment may be performed to react to produce a substance other than carbon dioxide gas, thereby suppressing the emission of carbon dioxide gas generated by power generation into the atmosphere.

In the first embodiment and the second embodiment, the cold heat of the low-temperature liquid fuel and the expansion energy at the time of vaporization of the low-temperature liquid fuel are utilized in the fuel cell system. Although the expansion energy during vaporization is utilized in the fuel cell system, the present invention is not limited to this, and only the cold heat of the low-temperature liquid fuel may be utilized in the fuel cell power generation system. Even if only the cold heat of the low-temperature liquid fuel is utilized in the fuel cell power generation system, energy loss can be reduced compared to the case where the cold heat of the low-temperature liquid fuel is not used.

While the first fuel cell stack 12 and the second fuel cell stack 14 used hydrogen ion conductive solid oxide fuel cells, the fuel cells used in the fuel cell power generation system of the present invention include: For example, other types of fuel cells such as molten carbonate fuel cells (MCFC), phosphoric acid fuel cells (PAFC), polymer electrolyte fuel cells (PEFC) can also be used.

In the fuel cell power generation system 10B of the second embodiment, the electric motor 40 is driven by the electric power generated by the generator 38, but the electric turbo chiller 44 is provided in the fuel cell power generation system 10B of the second embodiment, The cold generated by the machine 44 can also be used in the condenser 20 and chiller 32 instead of cold liquid fuel cold.

In the fuel cell power generation systems 10A-D of the first to fourth embodiments, the low-temperature liquid fuel is supplied from outside the system through the liquid fuel pipe P2. A fuel tank may be provided and the low-temperature liquid fuel may be supplied from the liquid fuel tank.

Although illustration is omitted, in the fuel cell power generation system 10A to D of the above embodiment, the flow rate of the oxidant gas and the fuel gas supplied to the first fuel cell stack 12 and the second fuel cell stack 14 is In order to control the pressure, temperature, etc., a pressure sensor, a flow sensor, a temperature sensor, a pressure adjustment valve, a flow adjustment valve, etc. connected to the control unit can be provided in the middle of the oxidant gas and fuel gas piping. .

10 fuel cell power generation system 12 first fuel cell stack (fuel cell)
12A first fuel electrode (fuel electrode)
14 Second fuel cell stack (fuel cell)
14A second fuel electrode (fuel electrode)
16 Cryogenic separation type oxygen production equipment (oxygen separation unit, non-gasification treatment equipment)
18 Oxygen burner (combustion part, non-gasification treatment device)
20 Condenser (carbon dioxide separation unit, non-gasification treatment device)
28 drive device (non-gasification treatment device)
30 compressor (first compressor, second compressor)
32 cooling equipment (non-gasification equipment)
38 Generator (non-gasification treatment equipment)
40 electric motor (non-gasification equipment)
44 Electric centrifugal chiller (non-gasification equipment)
48 Water electrolysis equipment (non-gasification equipment)
56 powder carbon generator (carbon generator)
63 drive device (oxidant gas compressor)
65 compressor (oxidant gas compressor)

Claims (9)

a liquid fuel supply unit supplied with a low-temperature liquid fuel having a temperature of 0° C. or lower;
a fuel cell that generates electric power with a fuel gas obtained by vaporizing the low-temperature liquid fuel and an oxidant gas containing oxygen, and discharges an off-gas containing a first carbon dioxide gas;
a non-gasification device for non-gasifying the first carbon dioxide gas using at least one of expansion energy when the low-temperature liquid fuel is vaporized and cold heat of the low-temperature liquid fuel;
with
The non-gasification treatment device liquefies at least the first carbon dioxide gas as the non-gasification treatment,
The non-gasification treatment device includes a cryogenic separation type oxygen production device that cools air with the cold heat of the low-temperature liquid fuel to generate liquid air, and then separates oxygen from the liquid air, and a fuel electrode of the fuel cell. The off-gas containing unburned carbon compounds discharged from and the oxygen separated by the cryogenic separation type oxygen production device are supplied, and the unburned carbon compounds in the off-gas are subjected to a combustion reaction with the oxygen. and a combustion unit that discharges a second carbon dioxide gas produced by the above process and a combustion off-gas containing the first carbon dioxide gas,
Fuel cell power generation system. a liquid fuel supply unit supplied with a low-temperature liquid fuel having a temperature of 0° C. or lower;
a fuel cell that generates electric power with a fuel gas obtained by vaporizing the low-temperature liquid fuel and an oxidant gas containing oxygen, and discharges an off-gas containing a first carbon dioxide gas;
a non-gasification device for non-gasifying the first carbon dioxide gas using at least one of expansion energy when the low-temperature liquid fuel is vaporized and cold heat of the low-temperature liquid fuel;
with
The non-gasification treatment device generates carbon from at least the first carbon dioxide gas as the non-gasification treatment,
The non-gasification treatment device includes a cryogenic separation type oxygen production device that cools air with the cold heat of the low-temperature liquid fuel to generate liquid air, and then separates oxygen from the liquid air, and a fuel electrode of the fuel cell. The off-gas containing unburned carbon compounds discharged from and the oxygen separated by the cryogenic separation type oxygen production device are supplied, and the unburned carbon compounds in the off-gas are subjected to a combustion reaction with the oxygen. and a combustion unit that discharges a second carbon dioxide gas produced by the above process and a combustion off-gas containing the first carbon dioxide gas,
Fuel cell power generation system. The non-gasification treatment device cools the combustion off-gas, condenses moisture from the combustion off-gas, and removes the first carbon dioxide gas and the second carbon dioxide gas contained in the combustion off-gas. Equipped with a carbon dioxide gas separation unit to separate,
The fuel cell power generation system according to claim 1 or 2 . 4. The fuel cell power generation system according to claim 3 , wherein said carbon dioxide gas separator cools said combustion off-gas with said cold heat of said low temperature liquid fuel. The non-gasification treatment device is
a driving device driven by expansion energy generated when the low-temperature liquid fuel is vaporized to generate power;
a first compressor driven by the power of the driving device for compressing the first carbon dioxide gas and the second carbon dioxide gas discharged from the carbon dioxide gas separation unit;
and a cooling device for obtaining liquefied carbon dioxide by cooling the first carbon dioxide gas and the second carbon dioxide gas compressed by the first compressor using the cold heat of the low-temperature liquid fuel. there is
The fuel cell power generation system according to claim 3 or claim 4 citing claim 1 . The non-gasification treatment device is
a driving device driven by expansion energy generated when the low-temperature liquid fuel is vaporized to generate power;
a generator driven by the power of the driving device to generate electric power;
an electric motor driven by the power generated by the generator;
a second compressor driven by the electric motor for compressing the first carbon dioxide gas and the second carbon dioxide gas discharged from the carbon dioxide gas separation unit;
and a cooling device for obtaining liquefied carbon dioxide by cooling the first carbon dioxide gas and the second carbon dioxide gas compressed by the second compressor using the cold heat of the low-temperature liquid fuel. there is
The fuel cell power generation system according to claim 3 or claim 4 citing claim 1 . The non-gasification treatment device is
a driving device driven by expansion energy generated when the low-temperature liquid fuel is vaporized to generate power;
a generator driven by the power of the driving device to generate electric power;
a water electrolysis device that electrolyzes water using the power generated by the generator to generate hydrogen gas;
a carbon generation unit that reacts the first carbon dioxide gas, the second carbon dioxide gas, and the hydrogen gas in a catalytic state to generate carbon,
The fuel cell power generation system according to any one of claims 1 to 6 . The non-gasification treatment device is
a driving device driven by expansion energy generated when the low-temperature liquid fuel is vaporized to generate power;
a generator driven by the power of the driving device to generate electric power;
an electric centrifugal chiller driven using the electric power generated by the generator;
a water electrolysis device that electrolyzes water using the power generated by the generator to generate hydrogen gas;
a carbon generation unit for generating carbon by reacting the first carbon dioxide gas, the second carbon dioxide gas, and the hydrogen gas on a catalyst,
The carbon dioxide gas separation unit cools the combustion off-gas discharged from the combustion unit with cold heat generated by the electric turbo chiller.
5. The fuel cell power generation system according to claim 3 or 4 . an oxidant gas compression device driven by the expansion energy when the low-temperature liquid fuel is vaporized, compressing the oxidant gas to a pressure exceeding atmospheric pressure and supplying the oxidant gas to the fuel cell;
The fuel cell is supplied with the high-pressure oxidant gas compressed by the oxidant gas compression device and the high-pressure fuel gas having a pressure exceeding the atmospheric pressure after the vaporization and expansion of the low-temperature liquid fuel, thereby generating electric power. and
having
The fuel cell power generation system according to any one of claims 1-8 .

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