JP2023101132A - Nitrogen gas generation device and method for dehumidifying fuel cell exhaust gas by water exchange - Google Patents

Abstract

To provide a device that reliably and stably generates high-purity nitrogen gas using a fuel cell.SOLUTION: A nitrogen gas generation device includes a fuel cell that operates by taking in gas including air or nitrogen and oxygen and fuel gas, water exchange dehumidification means that performs water exchange between exhaust gas having lower oxygen concentration than the air taken out of the fuel cell and the gas including air or nitrogen and oxygen introduced into the fuel cell, and reduces moisture or water vapor content in exhaust gas, and nitrogen filtering means that includes filters with different degrees of permeation for nitrogen and oxygen, and converts exhaust gas with reduced moisture or water vapor content into gas with increased nitrogen concentration, and preferably further includes high-pressure gas supply means capable of supplying, to the fuel cell, high-pressure air having pressure greater than or equal to a pressure threshold set on the basis of minimum pressure required or determined at least in the nitrogen filtering means and high-pressure gas containing nitrogen and oxygen.SELECTED DRAWING: Figure 1

Description

TECHNICAL FIELD The present invention relates to a technique for generating nitrogen gas with high purity.

In recent years, the use of fuel cells has been actively promoted. For example, fuel cell vehicles have been put into practical use, and household and industrial fuel cell facilities are also becoming popular. The use of fuel cells not only realizes highly efficient power generation, but also makes it possible to reduce carbon dioxide emissions to almost zero, unlike conventional power generation means using internal combustion engines. Therefore, fuel cell technology is expected to greatly contribute to the realization of a carbon-neutral society, which is an urgent issue, with a view to a zero-carbon society.

The inventors of the present application have paid attention to such potential of fuel cells and have invented various devices and systems using fuel cells, as described in Patent Documents 1 to 8. Here, in particular, as disclosed in Patent Documents 6 and 7, a nitrogen gas generator has been invented in which exhaust gas taken out from a fuel cell is acted on a nitrogen filter and gas with increased nitrogen concentration is taken out from this filter. Further, as disclosed in Patent Document 8, the inventors have invented a configuration for performing the dehumidification treatment of the exhaust gas, which is important in this nitrogen gas generator, using a water ring pump.

JP 2013-233549 A JP 2016-164987 A JP 2017-084796 A JP 2018-163890 A JP 2019-129110 A JP 2020-149838 A JP 2021-136084 A WO2021/172260

In this way, the inventors of the present application have come to realize that the use of fuel cells makes it possible to supply high-purity nitrogen gas, which is in great demand at various production and service provision sites.

Such high-purity nitrogen gas is an inert gas with neither combustion support nor combustion support, and is a very useful gas. Currently, it is produced by an air separation method, a membrane separation method, or the like. The inventors of the present application believe that it would be possible to efficiently generate high-purity nitrogen gas at low cost by using exhaust gas from a fuel cell instead of using air as a raw material. I thought there was no.

Here, one important issue is how to reduce the oxygen concentration of the exhaust gas. Another important issue is how to dehumidify the exhaust gas, which has a relative humidity of approximately 100%, taken out from the fuel cell. In this respect, if the exhaust gas is not properly dehumidified, it will be difficult to perform the subsequent oxygen concentration reduction treatment, making it difficult to perform the treatment reliably and stably. Of course, the nitrogen gas generators disclosed in Patent Documents 6 to 8, for example, are important solutions for solving these problems. I've been looking for a device configuration.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an apparatus, system, and method for reliably and stably producing high-purity nitrogen gas using a fuel cell.

According to the invention,
a fuel cell that operates by taking in air or a gas containing nitrogen and oxygen and a fuel gas;
Water exchange is performed between the exhaust gas having an oxygen concentration lower than that of the air taken out from the fuel cell and the air or the nitrogen and oxygen-containing gas taken into the fuel cell to remove moisture or water vapor in the exhaust gas. a reducing water exchange dehumidification means;
Provided is a nitrogen gas generator having filters with different degrees of permeation for nitrogen and oxygen, and nitrogen filtering means for converting the exhaust gas with reduced moisture or water vapor content into gas with increased nitrogen concentration.

As one embodiment of the nitrogen gas generator according to the present invention, the nitrogen gas generator includes at least high-pressure air or high-pressure gas having a pressure equal to or higher than a pressure threshold set based on the lower limit pressure required or determined in the nitrogen filtering means. further has a high-pressure gas supply means capable of supplying a gas containing nitrogen and oxygen of
The water exchange dehumidifying means reduces the moisture or water vapor content in the high pressure exhaust gas having a pressure equal to or higher than the pressure threshold,
It is also preferred that the nitrogen filtering means converts the high pressure exhaust gas with reduced moisture or water vapor content into gas with increased nitrogen concentration.

Further, in the above-described embodiment related to high-pressure gas supply, the present nitrogen gas generator includes a dry filtering means equipped with a dry filter for further reducing moisture or water vapor content in the high-pressure exhaust gas taken out from the water exchange dehumidifying means. and the pressure threshold is also preferably set based on the lower pressure limit required or determined in the dry filtering means. Furthermore, the lower limit pressure is preferably set to a pressure value of at least 3 atmospheres or more.

Further, in the above-described embodiment related to high-pressure gas supply, the present nitrogen gas generator reacts the high-pressure exhaust gas with reduced moisture or water vapor content and the fuel gas on the combustion catalyst before being taken into the nitrogen filtering means. or reacting the nitrogen-enriched gas and the fuel gas taken out from the nitrogen filtering means on a combustion catalyst to reduce the oxygen concentration in the high-pressure exhaust gas or the nitrogen-enriched gas It is also preferred to further have catalytic combustion means for further reduction.

Furthermore, in the above-described embodiment related to high-pressure gas supply, the nitrogen gas generator electrolyzes a decomposition target that is water or steam or a decomposition target containing water or steam that is supplied in a limited space, and the pressure Further comprising high pressure electrolysis means for producing high pressure hydrogen gas having a pressure above a threshold, the fuel cell taking in said high pressure hydrogen gas and said high pressure air or said high pressure nitrogen and oxygen containing gas. It is also preferable to discharge the high-pressure exhaust gas. It is also preferable to further include heat transfer means for transferring heat from the fuel cell to the high pressure electrolysis means and using at least the heat to generate the high pressure hydrogen gas.

Furthermore, in the embodiment provided with the above high-pressure electrolysis means, the nitrogen gas generator is
dry filtering means comprising a dry filter for further reducing the moisture or water vapor content in the high pressure exhaust gas removed from the water exchange dehumidifying means;
It is also preferable to further have water supply means for supplying water from the dry filtering means, or water from the dry filtering means and the fuel cell, to the high pressure electrolysis means as the decomposition target.

Further, in the embodiment provided with the above-described high-pressure electrolysis means, the present nitrogen gas generating apparatus is configured to pass the high-pressure exhaust gas with reduced moisture or water vapor content and the fuel gas over the combustion catalyst before being taken into the nitrogen filtering means. or by reacting the nitrogen-enriched gas and the fuel gas removed from the nitrogen filtering means on a combustion catalyst to reduce the oxygen concentration in the high-pressure exhaust gas or the nitrogen-enriched gas It further has a catalytic combustion means that further reduces the
It is also preferable that the catalytic combustion means uses at least the generated high-pressure hydrogen gas as the fuel gas used for catalytic combustion.

Furthermore, in embodiments comprising the high pressure electrolysis means described above, the high pressure gas supply means comprises:
gas pressure driving means for generating a driving force using the generated high-pressure hydrogen gas and/or the high-pressure oxygen gas having a pressure equal to or higher than the pressure threshold value generated by the high-pressure electrolysis means;
It is also preferred to include gas compression means for converting said air or said nitrogen and oxygen containing gas to said high pressure air or said high pressure nitrogen and oxygen containing gas by said received driving force.

Further, among the embodiments described above, in the embodiment provided with the catalytic combustion means, the present nitrogen gas generator transfers heat from the fuel cell to the catalytic combustion means, and uses at least the heat to It is also preferable to further include heat transfer means for heating the combustion catalyst required for catalytic combustion.

Furthermore, as another embodiment of the nitrogen gas generator according to the present invention, the nitrogen gas generator is
a pressure adjusting means for converting the exhaust gas taken out from the water exchange dehumidifying means into a high-pressure exhaust gas having a pressure equal to or higher than a pressure threshold value set based on at least the lower limit pressure required or determined in the nitrogen filtering means;
It is also preferable to further include dry filtering means provided with a dry filter for further reducing moisture or water vapor content in the high-pressure exhaust gas taken out from the pressure regulating means. Also, the lower limit pressure is preferably set to a pressure value of at least 3 atmospheres or more.

Furthermore, as still another embodiment of the nitrogen gas generator according to the present invention, the nitrogen gas generator controls the temperature of the exhaust gas taken out from the fuel cell and/or the temperature of the exhaust gas before it is introduced into the nitrogen filtering means. It is also preferable to further include temperature adjusting means for adjusting the temperature of the water exchange dehumidifying means and/or the nitrogen filtering means to a temperature equal to or higher than a temperature threshold set based on the lower limit temperature required or determined. Moreover, it is also preferable that the temperature control means uses heat from the fuel cell to control the temperature of the exhaust gas to a temperature equal to or higher than the temperature threshold.

Furthermore, as still another embodiment of the nitrogen gas generator according to the present invention, the fuel cell comprises a plurality of cells, which are structural units each including two electrodes with an electrolyte interposed therebetween, and the plurality of cells as a whole is divided into a plurality of functional cell sections, each functional cell section includes one or a plurality of continuous cells, is not electrically connected in series with other functional cell sections, and is an individual power generation amount control section An electrical connection is also preferred.

According to the present invention, also
a fuel cell that operates by taking in air or a gas containing nitrogen and oxygen and a fuel gas;
Water exchange is performed between the exhaust gas having an oxygen concentration lower than that of the air taken out from the fuel cell and the air or the nitrogen and oxygen-containing gas taken into the fuel cell to remove moisture or water vapor in the exhaust gas. a reducing water exchange dehumidification means;
Provided is a nitrogen gas generation system comprising filters having different degrees of permeability for nitrogen and oxygen, and nitrogen filtering means for converting the exhaust gas with reduced moisture or water vapor content into gas with increased nitrogen concentration.

According to the present invention, furthermore,
supplying air or a gas containing nitrogen and oxygen and a fuel gas to the fuel cell to operate the fuel cell;
Exchanging water between the exhaust gas having an oxygen concentration lower than that of the air taken out of the fuel cell and the air or the nitrogen and oxygen-containing gas taken into the fuel cell to reduce the moisture or water vapor content in the exhaust gas. reducing the
A nitrogen gas generation method comprising the steps of: making the exhaust gas with reduced moisture or water vapor content act on filters having different degrees of permeation of nitrogen and oxygen, and extracting the exhaust gas with increased nitrogen concentration from the filter. be done.

According to the present invention, it is possible to reliably and stably generate high-purity nitrogen gas using a fuel cell.

1 is a schematic diagram showing an embodiment of a nitrogen gas generator/system according to the present invention; FIG. 1 is a schematic diagram showing one embodiment of a combination of a water exchange dehumidifying means and a fuel cell according to the present invention; FIG. FIG. 4 is a schematic diagram showing another embodiment of filtering means according to the present invention; FIG. 3 is a schematic diagram showing another embodiment of the nitrogen gas generator/system according to the present invention. FIG. 3 is a schematic diagram showing still another embodiment of the nitrogen gas generator/system according to the present invention. FIG. 5 is a schematic diagram showing another embodiment of the high-pressure gas supply means according to the present invention; FIG. 4 is a schematic diagram for explaining another embodiment of the fuel cell unit according to the present invention;

EMBODIMENT OF THE INVENTION Below, the form for implementing this invention is demonstrated in detail, referring an accompanying drawing. In addition, in each drawing, the same component is indicated using the same reference number. Components that may have similar structures and functions may also be indicated using the same reference numerals. Furthermore, the dimensional ratios within and between constituent elements in the drawings are arbitrary for ease of viewing of the drawings.

[Nitrogen gas generator/system]
FIG. 1 is a schematic diagram showing an embodiment of a nitrogen gas generator/system according to the present invention.

The nitrogen gas generator 1 (or nitrogen gas generation system 1) as one embodiment of the present invention shown in FIG.
(A) A fuel cell 104 that operates by taking in "air or a gas containing nitrogen and oxygen" and "fuel gas" (hydrogen gas in this embodiment);
(B) water exchange between the "exhaust gas" (off-gas) taken from the fuel cell 104, which has an oxygen concentration lower than that of air, and the "air or gas containing nitrogen and oxygen" taken into the fuel cell 104; and a water exchange dehumidification unit (U) 105 that reduces the moisture or water vapor content in the "exhaust gas";
(C) It is equipped with filters with different degrees of permeation for nitrogen and oxygen, and has a nitrogen filtering U109 that converts "exhaust gas" with reduced moisture or water vapor content into gas with increased nitrogen concentration.

Among these, the nitrogen filtering U109 of (C) above further removes (filters) oxygen (O ₂ ) gas from the “exhaust gas” having an oxygen concentration lower than that of air, and a gas with an increased nitrogen concentration (in this embodiment, high-purity nitrogen gas). Here, the “exhaust gas” is a gas with a relative humidity of approximately 100% immediately after it is discharged from the fuel cell 104 . Therefore, dehumidification of the "exhaust gas" is very important in order to continuously perform a good nitrogen filtering process in the nitrogen filtering U109.

On the other hand, the water exchange dehumidification U105 of (B) above moves water vapor (H ₂ O) from "exhaust gas" to "air or gas containing nitrogen and oxygen" via, for example, a water vapor exchange membrane ( It is a dehumidifying means for converting the "exhaust gas" into a gas with reduced water content or water vapor content. The "exhaust gas" becomes a gas that can be subjected to a good nitrogen filtering process in the nitrogen filtering U109 by the water exchange dehumidifying U105.

Here, the "air or gas containing nitrogen and oxygen" taken into the fuel cell 104 is, conversely, humidified by the water exchange dehumidifier U105. As a result, particularly when the fuel cell 104 is a polymer electrolyte fuel cell (PEFC), the solid polymer membrane (electrolyte layer), which is the core of the fuel cell reaction, is maintained in a wet state to provide high proton conductivity. can maintain sexuality. As a result, a good fuel cell reaction can be carried out, and exhaust gas in which sufficient oxygen has been consumed can be provided.

Thus, the water exchange dehumidifier U105 not only prepares the output gas from the fuel cell 104 into a gas suitable for the nitrogen filtering process, but also (depending on the type and method of the fuel cell 104) Gases can be adjusted to be suitable for fuel cell reactions. That is, by combining the water exchange dehumidifier U105 with the fuel cell 104 and the nitrogen filter U109 in a way that mediates the two, high-purity nitrogen gas can be generated reliably and stably.

Incidentally, especially in the field of fuel cell vehicles, humidifiers are known in which the air entering the fuel cell is moistened by water vapor from the exhaust gas. For example, Japanese Patent Laid-Open No. 2006-156203 discloses a humidifier that exchanges water between an offgas and a supply gas via a permeable membrane (water vapor exchange membrane). However, this known humidifier is merely a means for humidifying the air taken into the fuel cell, and in fact, the exhaust gas emitted from the humidifier is exhausted and has not been used at all.

The terms "high purity" or "high purity" described above mean a state in which the oxygen concentration in the nitrogen gas is sufficiently reduced. Specifically, the nitrogen concentration in the "high-purity" or "high-purity" nitrogen gas produced in this embodiment (ml in 100 ml of the medium and the unit is vol%) is the field and application of the nitrogen gas For example, it may be defined as 95 vol% or more, or 99 vol% (2N) or more, or 99.9 vol% (3N) or more, or 99.99 vol% (4N) or more.

Further, hereinafter, the pressure (gas pressure) values of air, hydrogen gas, etc. are absolute pressure values based on vacuum, that is, the atmospheric pressure is 1 atm (approximately 0.1 M Pascal (Pa)). For example, the "9 atm" shown below is 8 atm when measured by a pressure gauge installed in the air or exhaust gas piping, based on the atmospheric pressure.

[Equipment/system configuration]
As also shown in FIG. 1, the nitrogen gas generator (system) 1 of the present embodiment includes:
(a) a high pressure gas supply unit (U) 101;
(b) fuel cell U103 comprising fuel cell 104;
(c) water exchange dehumidification U105;
(d) dry filtering U107 with dry filter 107F;
(e) nitrogen filtering U109 with nitrogen gas filter 109F;
(f) gas reformer U121;
(g) a pressure booster U123;
(h) hydrogen recovery U129;
(i) It is a device (system) equipped with an overall control U131, which takes in "air or a gas containing nitrogen and oxygen", generates high-purity nitrogen gas, and can be supplied to the outside. there is In the following description, air is taken in, but of course "a gas containing nitrogen and oxygen" may be taken in as well.

Further, the nitrogen gas generation system 1 may have, for example, a device provided with a fuel cell U103 and a water exchange dehumidifier U105, and a dry filter U107 and a nitrogen filter U109 outside this device. Here, the dry filtering U107 can be a unit in this device, or can be omitted as described later, depending on the case. Furthermore, the nitrogen gas generation system 1 does not include the gas reformer U121, and the hydrogen gas can be obtained from outside the system.

Furthermore, the nitrogen gas generation system 1 includes a piping joint connectable to the air intake and the exhaust gas outlet of the fuel cell 104, a water exchange dehumidifier U105, a dry filter U107, and a nitrogen filter U109. (system)” and “fuel cell U103” may be connected.

Incidentally, the material/energy transfer and the flow of the process to be performed, which are shown by connecting the components with arrows in the device/system configuration diagram of FIG. 1, can also be understood as an embodiment of the nitrogen gas generation method according to the present invention. be.

<High pressure gas supply means>
Also in FIG. 1, the high-pressure gas supply U101 in this embodiment is a compressor that compresses air taken in from the atmosphere and supplies the generated high-pressure air to the fuel cell U103 (water exchange dehumidifier U105), and this compressor a unit with an electric motor for actuating the Various types of compressors, such as a reciprocating type, scroll type, screw type, rotary type, or swing type, or a combination of two or more of these types, can be used as the compressor.

Also in this embodiment, the high pressure gas supply U101, as described in detail below, is at least in nitrogen filtering U109, preferably in dry filtering U107 and nitrogen filtering U109, based on a "lower pressure limit" required or determined (system 1) is set so that high-pressure air having a pressure equal to or higher than the set "pressure threshold" can be supplied to the fuel cell U103 (water exchange dehumidifier U105). Here, the "lower limit pressure", which will also be explained later, is usually a pressure value greatly exceeding the atmospheric pressure (1 atmosphere, about 0.1 megapascal (MPa)) and at least 3 atmospheres (about 0.3 MPa). Set to the pressure value.

Furthermore, the high-pressure gas supply U101 has a buffer tank, and the compressed air in this buffer tank may be temporarily preserved and stored while maintaining high pressure. Moreover, it is also preferable to pass the high-pressure air taken out from the buffer tank through an air filter and an oil filter provided by itself, and supply the high-pressure air from which minute dusts, oil components, and the like are removed.

Another preferred embodiment of the high-pressure gas supply U101, specifically an embodiment using a gas pressure motor and a compression pump, will be described later in detail with reference to FIG. Incidentally, if the site where the nitrogen gas generator (system) 1 is introduced has, for example, a compressed air supply facility, the high pressure gas supply U101 can be omitted.

Also in FIG. 1, the flow controller FCa is a device that controls the flow rate and pressure of high-pressure air supplied from the high-pressure gas supply U101 to the water exchange dehumidifier U105. Specifically, it can be a gas regulator and a mass flow controller (or flow switch). Here, in this embodiment, this high-pressure air is supplied to the water exchange dehumidifier U105 while maintaining a high pressure of, for example, 3 to 10 atmospheres (approximately 0.3 to 0.1 MPa).

<Water exchange dehumidifying means>
In this embodiment, the water exchange dehumidifier U105
(a) received high pressure air having a pressure equal to or greater than the above "pressure threshold", in this embodiment having a pressure as high as, for example, 3 to 10 atmospheres (approximately 0.3 to 0.1 MPa);
(b) Water exchange is performed with the exhaust gas having an oxygen concentration lower than that of air taken out from the fuel cell 104, thereby reducing the moisture or water vapor content in the exhaust gas of (b) above. This also humidifies the high-pressure air of (a) above, supplies moist high-pressure air to the fuel cell 104, and continuously maintains a suitable fuel cell reaction (for example, by keeping the electrolyte layer wet). It is also possible to have

The configuration and function of the water exchange dehumidifier U105 will be described later in detail with reference to FIG.

<Hydrogen generating means>
Also in FIG. 1, the gas reformer U121 takes in a hydrocarbon gas such as city gas or LP (Liquefied Petroleum) gas, mixes this hydrocarbon gas with steam, and produces hydrogen from this mixed gas by a steam reforming reaction. A hydrogen-containing gas containing (H ₂ ) as a main component is produced. Here, a CO modification catalyst or the like is used to reduce the amount of carbon monoxide gas contained in the generated hydrogen-containing gas, and a CO selective oxidation catalyst is used to further reduce the carbon monoxide concentration. It is also preferable to have

In addition, in this embodiment, the pressure booster U123 is equipped with a hydrogen storage alloy cylinder that temporarily stores and stores the hydrogen gas supplied from the gas reformer U121 in a compressed (high pressure) state. It is a unit that supplies to the fuel cell 104 .

Furthermore, the flow controller FCb is a device that controls the flow rate and pressure of the hydrogen gas supplied from the pressure booster U123 to the fuel cell 104. FIG. Specifically, it can be provided with a hydrogen gas regulator and a hydrogen gas mass flow controller (or flow switch). Here, in this embodiment, this high-pressure hydrogen gas is sent to the fuel cell 104 while maintaining a high pressure, for example, 3 to 10 atmospheres (approximately 0.3 to 0.1 MPa), which is equivalent to the pressure of the high-pressure air. supplied. As a result, it is possible to apply the same pressure to each layer surface side of the electrolyte layer of the fuel cell 104, thereby preventing damage to the electrolyte layer.

Similarly in FIG. It is a device for maintaining a predetermined set pressure, for example, 3 to 10 atmospheres (about 0.3 to 0.1 MPa) in this embodiment. That is, the exhaust gas discharged from the fuel gas chamber on the hydrogen electrode side of the fuel cell 104 (after some degree of condensed water has been removed by the drain Db), that is, the back pressure, is set at a predetermined set pressure (for example, 3 to 10 atmospheres). Plays a role in maintaining high pressure.

Specifically, the pressure controller PCc may include a back pressure valve and a pressure gauge, and control the back pressure on the hydrogen electrode side in the fuel cell 104 by adjusting the back pressure valve. Hereinafter, the "back pressure" value for both the hydrogen electrode side and the air electrode side is assumed to be 1 atm (approximately 0.1 MPa) when the exhaust side of the fuel cell 104 is open, that is, when the pressure of the exhaust gas is atmospheric pressure. .

Also in FIG. 1, the hydrogen recovery U 129 extracts unreacted residual hydrogen gas from the exhaust gas emitted through the pressure controller PCc using, for example, a known hydrogen gas filter or executor, and reuses it. is a unit. Here, in this embodiment, the hydrogen gas taken out is sent back to the hydrogen mixer Ma downstream of the flow controller FCb. In addition, the gas after extracting the hydrogen gas may be discharged to the outside.

In addition, the hydrogen recovery U 129 performs a dehumidification process to remove residual water vapor and moisture from the exhaust gas discharged through the pressure controller PCc as a pretreatment for removing unreacted residual hydrogen gas. It is also preferable to Here, specifically, this dehumidifying treatment includes, for example, a dehumidifier using silica gel, zeolite, etc., a dehumidifying device equipped with a pressurizing mechanism, a gravity separation type, a centrifugal separation type, a mist remover pad type, an airfoil separation type, etc. It is also preferably implemented by a gas-liquid separator, such as a barometric separation coalescer type, or even a dry filter device.

<Fuel cell unit>
Similarly in FIG. 1, the fuel cell U103 includes a fuel cell 104. In this embodiment,
(a) Humidified high-pressure air humidified by water exchange dehumidifier U105, which has a pressure equal to or higher than the above "pressure threshold", in this embodiment, for example, a high pressure of 3 to 10 atmospheres (about 0.3 to 0.1 MPa). ,
(b) high pressure supplied from the flow controller FCb (Gas Reformer U121) having a pressure equivalent to the high pressure air in (a) above, for example 3 to 10 atmospheres (approximately 0.3 to 0.1 MPa) The hydrogen gas is received from the air intake on the air electrode side and the hydrogen intake on the hydrogen electrode side of the fuel cell 104, respectively, and taken into the oxidizing gas chamber and the fuel gas chamber, respectively, to cause a fuel cell reaction.

Then, as a result of this fuel cell reaction, from the exhaust gas outlet on the air electrode side and the exhaust gas outlet on the hydrogen electrode side of the fuel cell 104,
(c) a high-pressure exhaust gas having an oxygen concentration lower than that of air, having a pressure equal to or higher than the above-mentioned "pressure threshold", in this embodiment having a pressure as high as, for example, 3 to 10 atmospheres (approximately 0.3 to 0.1 MPa);
(d) discharging a high pressure exhaust gas having a pressure equivalent to that of the exhaust gas of (c) above;

Here, the high-pressure exhaust gas of (c) above is then subjected to a certain amount of dew condensation water removed by the drain Da, and after being subjected to temperature adjustment to a temperature suitable for the subsequent water exchange dehumidification treatment by the temperature controller TCa, It is supplied to the water exchange dehumidifier U105 and dehumidified. Furthermore, it undergoes nitrogen filtering and the like, and is finally converted into high-purity nitrogen gas, which is the result of the device (system) 1 . In any case, this high-pressure exhaust gas is usually a gas with a relative humidity of approximately 100%, and the subsequent dehumidification treatment by water exchange dehumidification U105 or the like is very important. Incidentally, in this embodiment, since the exhaust gas is in a high-pressure state, its dew point is considerably high, and the amount of water falling into the drains Da and Db is correspondingly increased. That is, the drains Da and Db are also subjected to higher dehumidification.

Further, as described above, by setting the input/output of the fuel cell 104 to a high pressure, the fuel cell reaction is promoted, and as a result, high-pressure exhaust gas with a lower oxygen concentration can be taken out. Also, although it will be described in detail later as one embodiment,
High pressure gas supply U101 as air supply, high pressure water electrolysis U125 as hydrogen supply (described later with FIG. 5), fuel cell U103, water exchange dehumidification U105, dry filtering U107, (FIGS. 4 and 5 ), catalytic combustion U108, and nitrogen filtering U109
are connected by exchange of high-pressure gas, and in the entire device (system) 1, it is possible to generate high-pressure air to high-pressure high-purity nitrogen gas at high pressure all the way through with high efficiency.

The fuel cell 104 can have a known structure, for example, it has a structure in which an electrolyte layer is sandwiched between an air electrode (oxygen electrode, cathode, cathode) and a hydrogen electrode (fuel electrode, anode, anode). The cells may have a structure in which a plurality of cells are stacked (stacked) with separators interposed therebetween. In other words, each cell has a structure in which an oxidizing gas chamber on the air electrode side and a fuel gas chamber on the hydrogen electrode side are provided so as to sandwich an electrolyte layer.

Further, the fuel cell 104 is a polymer electrolyte fuel cell (PEFC) in this embodiment, but of course, a solid oxide fuel cell (SOFC), a phosphoric acid fuel cell (PAFC), a molten carbonic acid fuel cell A salt fuel cell (MCFC) or the like is also possible. Incidentally, the PEFC used in this embodiment operates at a relatively low temperature and can be made compact in battery size, so it is used in many fuel cell vehicles, for example.

The solid polymer membrane (electrolyte layer) in the fuel cell 104 adopting this PEFC system must be in a wet state in order to maintain high proton conductivity and continue good fuel cell reaction. In this regard, the high-pressure air of (a) taken into the fuel cell 104 is moist air humidified by the water exchange dehumidifier U105. As a result, the solid polymer membrane (electrolyte layer) receives moisture and water vapor from this moist high-pressure air and is able to maintain a moist state. It becomes.

In this embodiment, as described above, the fuel cell 104 receives the above (a) high pressure (eg 3 to 10 atmospheres) air and the above (b) high pressure (eg 3 to 10 atmospheres) hydrogen gas. It is a high-pressure type that discharges high-pressure (e.g., 3 to 10 atmospheres) exhaust gas from the oxidizing gas chamber (c) and high-pressure (e.g., 3 to 10 atmospheres) exhaust gas from the fuel gas chamber (d). ing. Here, the pressures in these oxidizing gas chambers and fuel gas chambers, that is, back pressures (for example, 3 to 10 atmospheres) are set by a pressure controller PCa equipped with a back pressure valve and a pressure controller PCc equipped with a back pressure valve, respectively. adjusted. In order to prevent the electrolyte layer of the fuel cell 104 from being damaged, the back pressure of the oxidizing gas chamber and the back pressure of the fuel gas chamber should be set to be equal, for example, with an error of less than 0.1 atmospheric pressure (approximately 0.01 MPa). is also preferred. If the back pressure on the oxidizing gas chamber side (air electrode side) can be controlled by a later-described pressure controller PCd provided after the nitrogen filter U109, the pressure controller PCa can be omitted.

Incidentally, it is also preferable to use, for example, a fuel cell with an introduction pressure of 9 atmospheres (approximately 0.9 MPa) and a rated output of several tens of kW (eg, 70 kW) as a high-pressure fuel cell. Here, by adopting a fuel cell with high output, the amount of exhaust gas taken out increases, and the amount (flow rate) of high-purity nitrogen gas finally generated can also be increased.

Further, the fuel cell U103 equipped with the fuel cell 104 as described above has the following characteristics: (a) the flow rate, pressure, and temperature of the high-pressure air and high-pressure hydrogen gas introduced into the fuel cell 104; Equipped with a group of measurement devices/sensors capable of measuring the flow rate, pressure, and temperature of discharged exhaust gas and discharged water vapor/moisture, and (c) the complex impedance between the hydrogen electrode and the air electrode of the fuel cell 104. is also preferred. Furthermore, it is also preferable that the operation of the fuel cell 104 is appropriately controlled by the overall control U131 that receives the measurement information from the measurement device/sensor group.

For example, as an example of simple control, fuel cell control (machine learning) using a DNN (Deep Neural Network) algorithm, etc., with the above (b) and (c) as explanatory variables and the above (a) as an objective variable. A model may be constructed and used to adjust the flow rate, pressure, and/or temperature of the hydrogen gas or air supplied to the fuel cell 104 so that the fuel cell 104 produces the desired output.

Further, the fuel cell U 103 has a heat exchanger that circulates a heat exchange medium such as water inside or around the fuel cell 104, extracts heat from the fuel cell 104 that has generated heat during operation, and transfers it to the outside of the unit. is also preferred. The heat exchangers that can be used here include shell and tube heat exchangers and other shell and tube heat exchangers, and Alfa Laval brazed plate heat exchangers and other plate heat exchangers. Alternatively, instead of the heat exchanger, a heat conduction system connecting the conductive separator and the heat pipe in the fuel cell 104 can be used to extract the heat in the fuel cell 104 directly to the outside. In any case, such a heat transfer means can control the cell temperature of the fuel cell 104 to a predetermined temperature (eg, 80° C.) or less, and maintain the fuel cell 104 in a favorable operation.

Here, the heat transferred by the heat transfer means such as the above heat exchanger or heat transfer system is, in this embodiment,
(a) a temperature controller TCa that adjusts the temperature of the high pressure exhaust gas supplied to the water exchange dehumidifier U105; and (b) a temperature controller TCb that adjusts the temperature of the high pressure exhaust gas supplied to the nitrogen filtering U109.
and used to control the temperature of the high-pressure exhaust gas. For example, it is also preferable to adjust the temperature by using the heat to change the temperature of a thin metal tube through which the high-pressure exhaust gas passes. Furthermore, this heat is preferably sent to a pressure regulation unit PCb equipped with an off-gas buffer tank, which will be described later, and used to regulate the temperature of the exhaust gas in the tank. Additionally, the heat transferred from the fuel cell 104 can be applied to the amount of heat required during steam reforming in the gas reformer U121.

The fuel cell U103 also supplies the power generated by the fuel cell 104 to the high pressure gas supply U101, which operates its own compressor with this power or with this power and utility power. It is also preferable to let As a result, it is also possible to suppress the power supply to the entire device (system) 1 (or reduce it to approximately zero).

In yet another embodiment, in the fuel cell U103, two or more fuel cells 104 are connected in series, and the second and subsequent fuel cells 104 are connected in series to the fuel cell 104 that is one before. It is also possible to adopt a configuration in which exhaust gas is taken in and used for the fuel cell reaction, and finally exhaust gas with a lower oxygen concentration (for example, exhaust gas with an oxygen concentration of 2.5 vol% or less) is taken out. Incidentally, the inventors of the present application disclose a fuel cell system having such a configuration invented in Japanese Patent Application Laid-Open No. 2019-129110.

Here, the fuel cell 104 of the present embodiment described above is a fuel cell compatible with high pressure (for example, 3 to 10 atmospheres). A battery is also possible. In this case, high pressure gas supply U101 and pressure booster U123 can be used to supply air or hydrogen gas, for example below 3 atmospheres (or 2 atmospheres), or depending on the gas pressure to be introduced into fuel cell 104. However, it may be omitted.

Also, in this case, the water exchange dehumidifier U105 exchanges water between the taken air of less than 3 atmospheres (or 2 atmospheres) and the exhaust gas of less than 3 atmospheres (or 2 atmospheres) taken out from the fuel cell 104, for example. to reduce the moisture or water vapor content in the exhaust gas. Of course, in this case as well, as will be described in detail later, the dehumidification process can be carried out reliably by adjusting the temperature difference between the air and the exhaust gas.

Hereinafter, such a fuel cell will be referred to as a "normal gas pressure type" fuel cell, and an embodiment using this "normal gas pressure type" fuel cell 104 will also be described as appropriate.

<Dry filtering means>
Also in FIG. 1, the dry filtering U107 is equipped with a dry filter 107F in this embodiment, and is a dehumidifying means for further reducing moisture or water vapor in the high-pressure (for example, 3 to 10 atm) exhaust gas taken out from the water exchange dehumidifying U105. is.

The dry filter 107F of the present embodiment, as shown in FIG. It is a filter that can take out dry exhaust gas with further reduced moisture or water vapor content from the outlet of the fiber membrane 107Fa. Here, a part (for example, 10 to 20%) of the dried exhaust gas taken out is returned to the surface side of the hollow fiber membrane 107Fa, and serves as a purge gas that takes in the water vapor that has permeated the hollow fiber membrane 107Fa and releases it out of the filter. used. As a modification, it is possible to use compressed air supplied from the outside (for example, installed in a factory) instead of part of the generated dry exhaust gas as the purge gas.

Further, the hollow fiber membrane 107Fa may be, for example, a fluorine-based non-porous membrane having a high affinity with water molecules. In any case, the hollow fiber membrane 107Fa is acted upon by a force to eliminate the difference in moisture concentration between the exhaust gas flowing inside the membrane and the purge gas flowing outside, and as a result, moisture and water vapor are transferred from the exhaust gas to the purge gas. I do.

In the dry filter 107F as described above, the higher the pressure of the introduced high-pressure exhaust gas (introduction pressure) and the smaller the flow rate of the introduced high-pressure exhaust gas (filter inlet flow rate), the more Experiments have confirmed that exhaust gases with low relative humidity (ie, lower dew point) can be extracted. For example, as a result of introducing exhaust gas with a relative humidity of 100% into a hollow fiber membrane type dry filter at a filter inlet flow rate of 100 liters (L) / minute, the relative humidity of the dry exhaust gas obtained is 2 when the introduction pressure is 2 It was 55% at atmospheric pressure (approximately 0.2 MPa) and 33% at introduction pressure of 4 atmospheric pressure (approximately 0.4 MPa). Furthermore, when the introduction pressure was 4 atmospheres (approximately 0.4 MPa) and the filter inlet flow rate was 50 L/min, the relative humidity of the obtained dry exhaust gas decreased to 20%.

By the way, for example, the inlet pressure is 9 atmospheres (about 0.9 MPa), the filter inlet flow rate is 520 L / min, and the outlet flow rate is 280 L / min (that is, the yield is 54%). When adopting a dry filter that can extract dry gas with a dew point of -60°C, by using N pieces (for example, 3) of these dry filters arranged in parallel, such dry exhaust gas can be removed. , a flow rate of 280×N (840 if N=3) L/min.

As described above, in the present embodiment, the dry filtering U107 further reduces the moisture or water vapor content in the high-pressure (eg, 3 to 10 atm) exhaust gas. Here, in this embodiment, this high pressure value is a value equal to or higher than the "lower limit pressure" required or determined in this dry filter 107F itself (not only in the nitrogen gas filter 109F of the nitrogen filter U109 that passes after this). there is Here, this "lower limit pressure" is a pressure value that greatly exceeds the atmospheric pressure (1 atmosphere, about 0.1 MPa) determined by the filter characteristics, and is usually at least 3 atmospheres (about 0.3 MPa) or higher. Set to the pressure value.

For example, to remove a desired flow rate of dry exhaust gas with a desired low relative humidity, the inlet pressure should be 9 atmospheres (approximately 0.9 MPa) or higher (i.e., the "lower pressure limit" should be 9 atmospheres (approximately 0.9 MPa). ) When using the dry filter 107F, the exhaust gas introduced into the dry filter U107 can be gas having a pressure of, for example, 9 to 9.5 atmospheres (approximately 0.9 to 0.95 MPa). Incidentally, in this case, the high-pressure gas supply U101, which is the high-pressure air supply source, is a "pressure threshold" set based on this "lower limit pressure" (9 atm) (taking into consideration the pressure loss in the device (system) 1). It is also preferred to generate high pressure air having a pressure of, for example, 9.5 atmospheres (about 0.95 MPa) or more.

As described above, the high-pressure fuel cell 104 and the dry filter U 107 form a series of high-pressure systems, thereby promoting the efficiency of the cell reaction and efficiently removing water and water vapor generated. Therefore, it is a very suitable combination. However, when the high pressure exhaust gas is sufficiently dehumidified by the water exchange dehumidification U105 in the previous stage, for example, the relative humidity of the high pressure exhaust gas may be supplied to the nitrogen filtering U109 by the water exchange dehumidification U105. dry filtering U107 may be omitted.

In the above, an embodiment having a high-pressure compatible fuel cell 104 and a dry filtering U107 has been described. It is also possible to take In this case, as shown in FIG. 1, a "pressure regulation unit PCb" may be provided in the preceding stage of the dry filtering U107.

This pressure regulating unit PCb sets the pressure of the exhaust gas taken out of the water exchange dehumidifier U105 at least in the nitrogen filtering U109 (here in the dry filtering U107 and the nitrogen filtering U109) based on the required or determined lower limit pressure. Adjust the pressure above the pressure threshold. For example, the pressure of the exhaust gas extracted from the water exchange dehumidifier U105 is adjusted to the introduction pressure (for example, 9 atmospheres) set in the dry filter U107 or higher.

Specifically, the pressure regulating unit PCb may comprise a compression pump, a booster pump or a gas-driven pressure increasing valve, and an off-gas buffer tank equipped with a gas pressure gauge. The exhaust gas extracted from the water exchange dehumidifier U105 is pressurized to a pressure equal to or higher than the introduction pressure set in the dry filtering U107, introduced into the offgas buffer tank, and temporarily stored. Here, it is also preferred to draw in some of the high pressure air from the high pressure gas supply U101 (if the high pressure gas supply U101 is provided as described above) and thereby drive the booster valve.

In addition, the off-gas buffer tank of the pressure regulation unit PCb receives heat transferred from the fuel cell U103 by means of heat transfer, such as a heat exchanger or a heat transfer system, to raise the exhaust gas in the tank to a temperature above room temperature. is also preferred. As a result, it becomes possible to supply exhaust gas having a temperature within a temperature range suitable for dry filtering to the dry filter 107F of the dry filtering U107. Of course, if the temperature of the exhaust gas taken out from the water exchange dehumidifier U105 is within a temperature range suitable for dry filtering, the heat treatment of the exhaust gas in the offgas buffer tank is unnecessary.

Here, by adopting the pressure regulation unit PCb described above, even in this embodiment using the "normal gas pressure type" fuel cell 104, the nitrogen filtering U109 and the catalytic combustion U108, which will be described later in detail, can be used. It becomes possible.

Moreover, such a pressure regulation unit PCb can also be employed in an embodiment using a fuel cell 104 that can handle high pressure. For example, if the pressure of the exhaust gas to be introduced into the dry filtering U107 does not reach the introduction pressure (for example, 9 atm) set in the dry filtering U107 due to circumstances such as the original setting or pressure loss on the way, the pressure adjustment unit PCb It is also preferable to make up for the lack of pressure. Of course, if there is no need for such pressure regulation, this pressure regulation unit PCb may be omitted.

<Nitrogen filtering means>
Also in FIG. 1, the nitrogen filter U109 in this embodiment filters high-pressure (for example, 3 to 10 atmospheres) exhaust gas with reduced moisture or water vapor content (taken out from the dry filter U107) using a nitrogen gas filter 109F. This is a means for making the gas with increased concentration, high-purity nitrogen gas in this embodiment.

Specifically, in this embodiment, the nitrogen gas filter 109F of the nitrogen filtering U109 is
(a) hollow fiber portions (109Fa in FIG. 3) having different degrees of permeation for nitrogen and oxygen;
(b) A filter inlet portion (109Fb in FIG. 3) for introducing high-pressure (for example, 3 to 10 atm) exhaust gas to act on the hollow fiber fiber portion of the nitrogen gas filter 109F, and nitrogen from this hollow fiber fiber portion A filter outlet (109Fc in FIG. 3) for taking out exhaust gas (high-purity nitrogen gas) with increased concentration,
(c) The gas containing oxygen molecules separated from the nitrogen molecules (in the exhaust gas) by the hollow fiber fiber portion of the nitrogen gas filter 109F (hereinafter abbreviated as filter exhaust gas) is treated as the exhaust gas (high A filter purge section (109Fd in FIG. 3) is provided separately from the pure nitrogen gas).

Among them, the hollow fiber portion of the nitrogen gas filter 109F is a hollow fiber polymer fiber that preferentially allows oxygen molecules to permeate rather than nitrogen molecules. While high-pressure exhaust gas (for example, 3 to 10 atm) flows through the hollow fiber fiber from the filter inlet, oxygen molecules selectively permeate through the polymer fiber. High-purity nitrogen gas is taken out from the filter outlet.

In addition, in such a hollow fiber portion, the higher the pressure (introduction pressure) of the high-pressure exhaust gas to be introduced, and the smaller the flow rate (outlet flow rate) of the high-pressure exhaust gas (high-purity nitrogen gas) to be taken out, the more Experiments have shown that the lower the oxygen concentration (introduced oxygen concentration) of the high-pressure exhaust gas to be introduced, the lower the oxygen concentration (outlet oxygen concentration) (that is, the higher the nitrogen concentration) gas can be taken out from the filter outlet. Confirmed.

Here, from the viewpoint of the dependency of the outlet oxygen concentration on the introduced oxygen concentration, the fuel cell 104 that discharges the exhaust gas with a low oxygen concentration and the nitrogen gas filter 109F that filters this exhaust gas are highly pure nitrogen gas. It is understood that it is a very suitable combination for generating Furthermore, it has been confirmed by experiments that the recovery rate (=outlet flow rate/introduction flow rate) increases as the introduced oxygen concentration decreases. Therefore, also from the viewpoint of recovery rate, the fuel cell 104 and the nitrogen gas filter 109F are a suitable combination capable of recovering a sufficient amount of high-purity nitrogen gas.

By the way, as the nitrogen gas filter 109F, specifically, for example, a UBE _N2 separator manufactured by Ube Industries using polyimide hollow fiber, a SEPURAN N2 membrane module manufactured by Daicel-Evonik, or a selective type nitrogen filter manufactured by Daicel-Evonik A gas filter or the like can be employed.

As described above, in the present embodiment, the nitrogen gas filter 109F further reduces the oxygen concentration in high-pressure (eg, 3 to 10 atm) exhaust gas. Here, in this embodiment, this high pressure value is a value equal to or higher than the "lower limit pressure" requested or determined in the dry filter 107F. Here, as described above, this "lower limit pressure" is a pressure value that greatly exceeds the atmospheric pressure (1 atmosphere, about 0.1 MPa) determined by the filter characteristics, and is usually at least 3 atmospheres (about 0.3 MPa). ) is set to a higher pressure value than

For example, in order to take out a desired flow rate of nitrogen gas (exhaust gas) with a desired low oxygen concentration, the introduction pressure should be 8 atmospheres (about 0.8 MPa) or more (that is, the "lower limit pressure" is 8 atmospheres (about 0.8 MPa) When using the nitrogen gas filter 109F, the exhaust gas introduced into the nitrogen gas filter 109F can be gas having a pressure of, for example, 8 to 8.5 atmospheres (approximately 0.8 to 0.85 MPa). Incidentally, in this case, the high-pressure gas supply U101, which is the high-pressure air supply source, is a "pressure threshold" that is set based on the "lower limit pressure" (8 atm) (taking into consideration the pressure loss in the device (system) 1). For example, it is also preferable to generate high-pressure air having a pressure of 8.5 atmospheres (about 0.85 MPa) (eg, 9.5 atmospheres (about 0.95 MPa) considering the requirements of the dry filter 107F as described above) or more.

One example is given here. A UBE _N2 separator NM-B01A manufactured by Ube Industries was used as the nitrogen gas filter 109F, and a nitrogen-oxygen mixed gas having a temperature of 50°C and an oxygen concentration of 5.1 vol% was introduced into the nitrogen gas filter 109F. When the gas was introduced at a pressure of 7.0 atmospheres (approximately 0.7 MPa), high-purity nitrogen gas with an oxygen concentration of approximately 1000 ppm vol (0.1 vol%) was obtained when the outlet flow rate was set at 1.0 L/min. When a nitrogen-oxygen mixed gas with an oxygen concentration of 1.1 vol% was introduced under the same conditions, high-purity nitrogen gas with an oxygen concentration of about 300 ppm vol (0.03 vol%) was obtained.

As described above, the high-pressure compatible fuel cell 104, the dry filtering U107, and the nitrogen filtering U109 form a high pressure (gas pressure) one-through system, thereby promoting the efficiency of the cell reaction. Since it is possible to efficiently remove the generated moisture and water vapor and further reduce the oxygen concentration in the exhaust gas, it is a very suitable arrangement for producing high-purity nitrogen gas. For example, the exhaust gas pressure of 8 to 10 atmospheres (approximately 0.8 to 10 MPa) is controlled to be consistently maintained by the pressure controller PCa, the pressure adjustment unit PCb, and the pressure controller PCd, which will be described later. good too.

However, as described above, if the relative humidity of the high-pressure exhaust gas is lowered to the extent that it can be supplied to the nitrogen filtering U109 by the water exchange dehumidification U105 (to the extent that nitrogen filtering is effectively performed), the dry filtering U107 is provided. It doesn't have to be. Incidentally, in a certain nitrogen gas filter 109F, good nitrogen filtering can be performed for high-pressure exhaust gas with a relative humidity of about 20%, and nitrogen filtering can be performed even on high-pressure exhaust gas with a relative humidity of about 60%. Experiments have confirmed that this is possible.

Furthermore, the fuel cell 104, the dry filtering U107, and the nitrogen filtering U109 reduce the hydrogen gas content in the nitrogen gas generated from the exhaust gas as much as possible, and from the viewpoint of providing nitrogen gas with higher purity, it is very It is a suitable combination. In fact, the high-pressure exhaust gas discharged from the air electrode side (oxidizing gas chamber side) of the fuel cell 104 usually contains hydrogen gas leaked from the fuel gas chamber on the hydrogen electrode side and hydrogen gas as a residue of the purge gas. Approximately 1 to 3 vol% is mixed depending on the situation.

On the other hand, many of the hollow fiber membranes that can be used for the dry filter 107F selectively permeate not only water vapor (H ₂ O) but also hydrogen (H ₂ ) more than nitrogen (N ₂ ). have the property By using the dry filter 107F having the hollow fiber membrane 107Fa having such properties, it is possible to greatly reduce the hydrogen gas content in the high-pressure exhaust gas or to substantially eliminate it.

Furthermore, many of the hollow fiber fibers that can be used for the nitrogen gas filter 109F also have the property of selectively permeating not only oxygen (O ₂ ) but also hydrogen (H ₂ ) more than nitrogen (N ₂ ). have Also by using the nitrogen gas filter 109F having a hollow fiber portion (109Fa in FIG. 3) having such properties, the hydrogen gas content in the high-pressure exhaust gas can be greatly reduced or made almost zero. of.

Various instruments/devices provided upstream of the nitrogen filter U109 will be described below.

Similarly, in FIG. 1, the various filter units FLa remove sulfides, chlorides, hydrocarbons, fluorides, etc. that are harmful to the hollow fiber portion of the nitrogen gas filter 109F from the high-pressure exhaust gas supplied to the nitrogen filter U109. , a unit for removing or reducing strong alkaline compounds. Specifically, the various filter units FLa are equipped with, for example, activated carbon filters, and remove or reduce the above impurities in the exhaust gas as much as possible. Moreover, the various filter units FLa also include a mist filter and a dust filter, and preferably remove or reduce mist such as water mist, solvent mist, and oil mist in the exhaust gas.

Also in FIG. 1, the temperature controller TCb makes the temperature of the high-pressure exhaust gas taken in close to or coincides with a preset suitable temperature (for example, 35 to 60 ° C.) based on the characteristics of the nitrogen gas filter 109F, and the temperature is adjusted. Device for supplying high pressure exhaust to nitrogen filtering U109. Here, in this embodiment, the temperature controller TCb adjusts the temperature of the metal tubule through which the high-pressure exhaust gas passes, for example, with the heat transferred from the fuel cell U103 by a heat transfer means such as a heat exchanger or a heat conduction system. It is also preferable to adjust the temperature by changing the Alternatively, an electric heater may be provided, and the exhaust gas temperature may be adjusted by electric power supplied from the fuel cell U103. Of course, if the temperature of the exhaust gas supplied to the nitrogen filter U109 is sufficiently high, this temperature regulator TCb can also be omitted.

Here, the above-mentioned temperature regulators TCa and TCb respectively control the temperature of the high-pressure exhaust gas taken out from the fuel cell 104 and the temperature of the high-pressure exhaust gas before it is introduced into the nitrogen filter U109 to the water exchange dehumidifier U105. And the nitrogen filtering U109 is a means for controlling the temperature above the "temperature threshold" (for example, 60°C and 50°C) set based on the "lower limit temperature" requested or determined. In other words, it is a means for adjusting the exhaust gas temperature throughout the entire apparatus (system) 1 . For example, it may be adjusted to maintain a consistent exhaust gas temperature of 60-80°C.

Further, as described above, these temperature regulators TCa and TCb use heat from the fuel cell 104 (heat transferred by heat transfer means such as heat exchangers or heat transfer systems) to It is also preferable to control the temperature of to a temperature equal to or higher than the "temperature threshold". The "lower limit temperature" in the water exchange dehumidification U105 will be explained in detail later using FIG.

Next, various instruments/devices provided after the nitrogen filter U109 will be described.

Similarly to the pressure controller PCa, the pressure controller PCd in FIG. , the high-pressure (eg, 3 to 10 atm) exhaust gas having a pressure higher than the "pressure threshold" is introduced into the dry filter U107 or the nitrogen filter U109. That is, the pressure controller PCd serves as pressure control means for maintaining at least the dry filtering U107 to the nitrogen filtering U109 as a series of high pressure systems. Further, in the present embodiment employing the high-pressure fuel cell 104, the fuel cell U103 (fuel cell 104) through the dry filter U107 to the nitrogen filter U109 serve to maintain a series of high-pressure systems. Incidentally, in this case, the pressure controller PCa can be omitted as described above.

Also in FIG. 1, the flow controller FCc controls the flow rate of the high-pressure exhaust gas with increased nitrogen concentration generated by the nitrogen filter U109, in this embodiment, the high-pressure high-purity nitrogen gas. is supplied at a predetermined flow rate to a nitrogen gas tank outside the apparatus (system) 1 or to a device that requires high-purity nitrogen gas. Specifically, this flow controller FCc may comprise a gas regulator and a mass flow controller (or flow switch).

In any case, in the present embodiment, the high-purity nitrogen gas as a result of the apparatus (system) 1 is in a high-pressure state, and can be supplied as it is to a supply destination that requires high-pressure nitrogen gas. It is possible to reduce the pressure by using a decompression valve or the like and supply it to a destination that does not require it. In addition, the overall control U131 confirms the measurement data received from the oxygen concentration meter Oa and the gas pressure gauge Pa provided in the latter stage of the nitrogen filtering U109, and the quality (low oxygen concentration) of the high-purity nitrogen gas provided to the outside It is also preferable to check whether the gas pressure meets the specifications.

As described above, the nitrogen gas generator (system) 1 of the present embodiment generates not only high-purity nitrogen gas, but also electric power, heat (energy), and water (pure water). The result can be provided externally. In other words, it functions as a nitrogen gas/power/heat/water supply device (system).

Here, applications and methods of use of the high-purity nitrogen gas generated by the nitrogen gas generator (system) 1 will be described. As described above, high-purity nitrogen gas is in great demand at various production and service sites. It is an essential gas for the atmosphere.

In addition, there are many cases where "nitrogen gas mixed with a predetermined amount of hydrogen gas" is used as such a reducing atmosphere. The nitrogen gas generator (system) 1 uses the hydrogen gas remaining (or intentionally left) in the exhaust gas discharged from the fuel cell 104 as it is, or performs gas reforming U121 or high-pressure water electrolysis to be described later. By mixing the hydrogen gas generated in U125 (FIG. 5), or by using the hydrogen gas remaining (or intentionally left) after the catalytic combustion treatment in the catalytic combustion U108, which will be described later, as it is. It is also possible to provide such "nitrogen gas mixed with a predetermined amount of hydrogen gas".

Furthermore, the high-purity nitrogen gas generated by the nitrogen gas generator (system) 1 can also be used as means for removing or reducing dissolved oxygen in water or oil. For example, it is used in mold cooling water, cleaning water for semiconductors, circulating water for various heat storage tanks, boiler water supply, cooling water for air conditioning, edible water used in the production of juice, tea, beer, etc., edible oil, fryers, etc. For frying oil, water, oil, etc., which are raw materials for various chemical products, for rust prevention of piping, necessity in the manufacturing / processing process of manufacturing / processed products, and maintenance of quality of manufactured / processed products, It is necessary to apply a deoxidizing treatment to remove or reduce a considerable amount of dissolved oxygen (O ₂ ).

Specifically, as this deoxygenation treatment, for example, a treatment of blowing high-purity nitrogen gas of, for example, 3N (nitrogen concentration 99.9 vol %) into water to be treated is performed. When high-purity nitrogen gas is blown into water in this way, nitrogen (N ₂ ) and oxygen (O ₂ ) find an equilibrium state according to Henry's law at the interface between the gas phase and the liquid phase, and flow beyond the interface. Moving. As a result, the oxygen dissolved in the water is mixed as oxygen gas into the bubbles of the high-purity nitrogen gas blown into the water, and is finally discharged out of the water together with the bubbles of the high-purity nitrogen gas.

Thus, if the high-purity nitrogen gas generated by the nitrogen gas generator (system) 1 is used, oxygen (O ₂ ) dissolved in water or oil can be removed safely and reliably without using chemicals, for example. It becomes possible to remove or reduce them.

[Water exchange dehumidification U105]
FIG. 2 is a schematic diagram showing one embodiment of a combination of water exchange dehumidifying means and a fuel cell according to the present invention.

First, the water exchange dehumidifier U105 of this embodiment shown in FIG.
(a) high-pressure (for example, 3 to 10 atmospheres) air introduced into the humidification chamber 105H from the high-pressure gas supply U101 via the flow controller FCa;
(b) Exchanging water with high-pressure (for example, 3 to 10 atm) exhaust gas introduced into the dehumidifying chamber 105D from the oxidizing gas chamber 104X of the fuel cell 104 via the temperature controller TCa through the water vapor exchange membrane 105V. to reduce the moisture or water vapor content in the high-pressure exhaust gas in (b) above.

The water vapor exchange membrane 105V receives water vapor (H ₂ O) from the high-pressure exhaust gas flowing in the dehumidifying chamber 105D, permeates it, and transfers it to the high-pressure air flowing in the humidifying chamber 105H. This membrane permeation/transfer process of water vapor is an endothermic reaction, and in order to advance this process (endothermic reaction), the temperature of the high-pressure exhaust gas flowing in the dehumidification chamber 105D is equal to the temperature of the high-pressure air flowing in the humidification chamber 105H. must be maintained higher than

The degree of progress of this membrane permeation/migration process naturally depends on the water vapor partial pressures of both (and also depends on the flow rates of both), but since it is an endothermic reaction, both , and the temperature of the high-pressure exhaust gas must be set to a sufficiently high temperature. In this regard, the temperature of the exhaust gas discharged from the fuel cell 104 is usually about 55 to 80° C. in the case of PEFC, for example, which is sufficiently high compared to high-pressure air, which usually has a temperature of about room temperature (for example, 25° C.). The temperature is high. For example, it is known that about 30% of the moisture and water vapor in the high-pressure exhaust gas can be transferred to the high-pressure air if this temperature difference is maintained.

Incidentally, the pressure of the high-pressure air in (a) (for example, 3 to 10 atmospheres) and the pressure of the high-pressure exhaust gas in (b) (for example, 3 to 10 atmospheres) are both installed after the water exchange dehumidifier U105. are controlled by the pressure controller PCa (FIG. 1), and are similar to each other in terms of the structure of the flow path. Therefore, it is possible to avoid a situation in which the water vapor exchange membrane 105V is damaged by the high pressure applied.

Further, as described above, the process of permeation/transfer of water vapor (H ₂ O) in the water vapor exchange membrane 105V is a reaction that continuously absorbs heat. must maintain a condition in which the temperature difference from the high-pressure exhaust gas is a predetermined value or more. Therefore, in the present embodiment, a gas thermometer Tc and a gas thermometer are provided in the front and rear stages of the humidification chamber 105H into which high-pressure air is introduced and taken out, and in the front and rear stages of the dehumidification chamber 105D into which high-pressure exhaust gas is introduced and taken out, respectively. Td, a gas thermometer Ta and a gas thermometer Tb are installed.

The general control unit U131 monitors the temperature of these gas thermometers, adjusts the amount of high-pressure air introduced by the flow controller FCa so that the temperature difference is equal to or greater than a predetermined value, and adjusts the amount of high-pressure exhaust gas by the temperature controller TCa. to adjust the temperature of This makes it possible to generate high-pressure exhaust gas that has been reliably dehumidified (relative humidity reduced to a target value or less). On the other hand, the humidified high-pressure air is supplied to the oxidizing gas chamber 104X of the fuel cell 104, moistens the electrolyte layer 104E provided between the fuel gas chamber 104H, and continues good fuel cell reaction. of.

Here, the temperature adjuster TCa adjusts the temperature of the high-pressure exhaust gas extracted from the fuel cell 104 to a "temperature threshold" (for example, 60 °C) is a means for controlling the temperature above. In addition, this "lower limit temperature" is determined from the "temperature difference" (between high-pressure exhaust gas and high-pressure air) that is the minimum required to achieve the dehumidification effect (reduction of relative humidity) set in the water exchange dehumidification U105. is the temperature value. For example, if the temperature of the high pressure air is 25°C and the minimum required "temperature difference" is 30°C, the "lower limit temperature" is 55 (=25 + 30)°C.

An embodiment of the water exchange dehumidifier U105 has been described above. As this water exchange dehumidifier U105, for example, a Perma Pure humidifier equipped with a Nafion (registered trademark, Nafion) membrane tube as a water vapor exchange membrane 105V is adopted. can do.

The combination of the high-pressure compatible fuel cell U103 (fuel cell 104) and the water exchange dehumidifier U105 handling high-pressure gas has been described above. Here, a preferred embodiment of the high pressure fuel cell 104 will be described.

As shown in FIG. 2B, the fuel cell 104 of this embodiment is
(a) a cell stack 104S which is a battery body;
(b) a heat exchange section 104G for transferring heat generated by the fuel cell reaction in the cell stack 104S to the outside using a heat exchange medium;
(c) A pressure vessel containing the cell stack 104S and the heat exchange section 104G in a vessel filled with a high-pressure filling gas such as air (in this embodiment, filled with high-pressure gas from the high-pressure gas supply U101). 104C;
(d) a pressure gauge 104Pa that monitors the pressure of the filling gas in the pressure vessel 104C;
(e) Based on the monitored value of the gas pressure in the pressure vessel 104C by the pressure gauge 104Pa, the pressure vessel 104C is replenished with the filling gas that has escaped from its interior (or the filling gas is exchanged with the pressure vessel 104C). ), and an in-vessel pressure regulator 104P for maintaining the gas pressure in the pressure vessel 104C at a “predetermined pressure value”.

Here, in the cell stack 104S of (a) above, a plurality of cells having a structure in which an oxidizing gas chamber on the air electrode side and a fuel gas chamber on the hydrogen electrode side are provided with an electrolyte layer sandwiched therebetween are stacked. It is the battery body. In addition, the in-container pressure regulator 104P of (e) above includes a gas regulator (which can be adjusted according to the monitored value of the gas pressure) in this embodiment, and the high-pressure air as the filling gas is directly supplied from the high-pressure gas supply U101. The received high-pressure air is adjusted by the gas regulator and supplied to the pressure vessel 104C so that the gas pressure in the pressure vessel 104C is set to a "predetermined pressure value". Here, this "predetermined pressure value" (in (e) above) is a value equivalent to or slightly higher than the pressure (introduction pressure) of the high-pressure gas (high-pressure air or high-pressure hydrogen gas) introduced into the cell stack 104S. It is also preferably set to a high value. In this respect, in the present embodiment, the high pressure air itself from the high pressure gas supply U101 is used as the filling gas, so such pressure setting is facilitated. In addition, as a modification mode, the in-vessel pressure regulator 104P and the pressure gauge 104Pa may be omitted, and high-pressure air may be directly supplied from the high-pressure gas supply U101 into the pressure vessel 104C.

In any case, in the fuel cell 104 as described above, the cell stack 104S holding a high-pressure gas of, for example, 9 atmospheres (about 0.9 MPa) inside the pressure vessel 104C is supplied with a pressure of about 9 atmospheres, for example. subjected to compressive force. As a result, the fuel cell 104 can stably maintain the internal high pressure state without being damaged or destroyed by the internal high pressure gas, and can continuously carry out the high pressure fuel cell reaction.

A portion of the high pressure air (from the water exchange dehumidifier U105) introduced into the oxidizing gas chamber of the fuel cell 104 may be used as the fill gas. In addition, instead of the high-pressure air from the high-pressure gas supply U101, compressed air from a compressed air supply facility or the like, or compressed nitrogen gas from a nitrogen gas tank or a compressed nitrogen gas supply facility or the like can be used as the filling gas. is. Further, the vessel internal pressure regulator 104P includes a cylinder or a buffer tank with a pressure/flow rate control function containing the filling gas to be supplied to the pressure vessel 104C (or to be exchanged with the pressure vessel 104C), and a tank for supplying the filling gas. may be provided with a pump of Furthermore, of course, the high-pressure fuel cell 104 is not limited to the one described above. For example, without using the pressure vessel 104C, the cell stack 104S itself may be made to have a pressure-resistant structure so as to cope with a high introduction pressure. In any case, as described above, in order to prevent damage to the electrolyte layer 104E of the fuel cell 104, the introduction pressure (back pressure) of the oxidant gas chamber and the introduction pressure (back pressure) of the fuel gas chamber are set to, for example, 0.1. It is also preferable to set them to be equal, with an error of less than atmospheric pressure (approximately 0.01 MPa).

[Another embodiment of nitrogen filtering U109]
FIG. 3 is a schematic diagram showing another embodiment of filtering means according to the present invention.

The nitrogen gas filter 109F in the nitrogen filtering U109 of the embodiment shown in FIG. The filter outlet 109Fc for extracting high-purity nitrogen gas (in this embodiment) from the hollow fiber fiber portion 109Fa and the filter exhaust gas containing oxygen gas separated by the hollow fiber fiber portion 109F are referred to as high-purity nitrogen gas. A separate filter purge section 109Fd is provided.

Since the filter exhaust gas taken out from the filter purge section 109Fd here contains a considerable amount of the separated oxygen gas, it can be used again for the fuel cell reaction or subjected to nitrogen filtering again. It is gas.

By the way, when UBE N ₂ separator NM-B01A manufactured by Ube Industries is used as the nitrogen gas filter 109F, a gas with an oxygen concentration of 10.2 vol% is supplied at an introduction pressure of 6.0 atmospheres (about 0.61 MPa) and an outlet flow rate of 1.0 L/ When it was introduced into this nitrogen gas filter 109F under the conditions of minutes, the oxygen concentration of the filter exhaust gas discharged from there was 14.9 vol%, which is considerably high, and the recovery rate (= outlet flow rate / introduction flow rate) was 0.29. Incidentally, it has been confirmed by experiments that the oxygen concentration in the exhaust gas from the filter increases as the introduced oxygen concentration increases, the introduced pressure decreases, and the outlet flow rate increases.

Therefore, in this embodiment, the nitrogen filtering U109 filters the filter exhaust gas discharged from the nitrogen gas filter 109F into
(a) sent back to the flow controller FCa (FIG. 1) provided in the front stage of the fuel cell U103, and used again as an oxidizing gas in the fuel cell 104 as a gas containing oxygen and nitrogen;
(b) Sending back to the offgas buffer tank of the pressure regulation unit PCb (FIG. 1) provided in the preceding stage (in this embodiment, the preceding stage of the dry filtering U107), and automatically Nitrogen filtering is applied again. This makes it possible to finally take out nitrogen gas with a lower oxygen concentration. However, if the oxygen concentration of the exhaust gas from the filter is about the same as or higher than that of air (20.8 vol%), it should be noted that the above advantages of returning the exhaust gas from the filter to the air electrode side of the fuel cell 104 do not occur. Should.

Further, as shown in FIG. 3, the nitrogen filter U109 of this embodiment is provided with three nitrogen gas filters 109F1, 109F2 and 109F3 connected in parallel. Of course, the number of nitrogen gas filters arranged in parallel is not limited to three, and may be two or four or more.

Specifically, the high-pressure exhaust gas supplied to the nitrogen filter U109 is split and taken into each of the three nitrogen gas filters 109F1, 109F2, and 109F3, and each nitrogen gas filter takes in the supplied high-pressure exhaust gas. The nitrogen-enriched gas, i.e., high-purity nitrogen gas, is produced, and finally these high-purity nitrogen gases are combined and delivered from the nitrogen filter U109.

In addition, the filter exhaust gas discharged from each of the three nitrogen gas filters 109F1, 109F2, and 109F3 is sent back to the flow controller FCa (FIG. 1) upstream of the fuel cell U103 and contains oxygen and nitrogen, as described above. As a gas, it is used again in the fuel cell 104 as an oxidizing gas, or sent back to the offgas buffer tank of the pressure regulation unit PCb (FIG. 1), mixed with the high pressure exhaust gas, and subjected to (dry filtering and nitrogen filtering) again. It is also preferable to

As explained above, by arranging multiple nitrogen gas filters in parallel and performing nitrogen filtering, it is possible to take in a large amount of high-pressure exhaust gas at the same time and provide a larger amount of high-purity nitrogen gas to the outside. Become. For example, Daicel-Evonik's 4-inch diameter nitrogen gas filter, according to its catalog value, has an oxygen concentration of approximately 0.1 vol% when receiving 8 atmospheres (approximately 0.8 MPa) of air at a flow rate of 40 L/min. It is said that high-purity nitrogen gas is discharged at a flow rate of about 10 L/min (with a recovery rate of about 0.25).

For example, three such nitrogen gas filters are arranged in parallel, and exhaust gas (with an oxygen concentration lower than that of air, such as an oxygen concentration of 5 to 10 vol%) is applied to each nitrogen gas filter at 8 atmospheres (about 0.8 MPa). ) and at a flow rate of 40 L / min, the oxygen concentration is on the order of 0.01 vol% (100 ppm vol), or the oxygen concentration is significantly below 0.1 vol% (1000 ppm vol), for example, high-purity nitrogen with an oxygen concentration of the order of 100 ppm vol It is also possible to provide the gas to the outside at a total flow rate of about 30 (=10 x 3) L/min. Here, exhaust gas flows into each nitrogen gas filter at a flow rate of 1/3 of the original total flow rate of 120 (= 40 x 3) L/min. Therefore, the oxygen separation capacity of each nitrogen gas filter is further improved. Of course, if a nitrogen gas filter with a larger diameter, for example, a diameter of 6 inches is used, a larger amount of high-purity nitrogen gas can be supplied.

[Catalytic Combustion U108]
FIG. 4 is a schematic diagram showing another embodiment of the nitrogen gas generator/system according to the present invention.

Compared to the embodiment shown in FIG. 1, the nitrogen gas generator (system) 1 of this embodiment shown in FIG. is provided. This catalytic combustion U108
(a) high pressure (e.g., 3-10 atmospheres) flue gas with reduced moisture or water vapor content prior to introduction into nitrogen filtering U109;
(b) Hydrogen gas generated in the gas reforming U121, for example, high-pressure (for example, 3 to 10 atm) hydrogen gas taken out from the latter stage of the hydrogen mixer Ma is placed on the combustion catalyst, and in this embodiment, on the solid catalyst 108C. It is a means for further reducing the oxygen concentration in the high-pressure exhaust gas of the above (a) by bringing it into contact with the surface to cause a catalytic combustion reaction.

As described above, in the catalytic combustion U 108 of the present embodiment, high-pressure (for example, 3 to 10 atm) gases come into contact with each other on the combustion catalyst, so the reaction rate of the catalytic combustion reaction increases and the reaction is further promoted. The effect of reducing the oxygen concentration in the high-pressure exhaust gas is improved. Furthermore, the high-pressure hydrogen gas to be brought into contact with the high-pressure exhaust gas does not need to be procured from the outside of the device (system) 1 as described in (b) above.

In addition, the solid catalyst 108C, which is the combustion catalyst of the present embodiment, has many fine holes, and metals such as platinum (Pt), palladium (Pd), and nickel (Ni) are applied to the surface including the inside of the holes. A ceramic honeycomb supported as a catalyst may also be used. Further, as such a solid catalyst 108C, for example, an NA honeycomb, which is an oxidation catalyst (platinum catalyst) manufactured by Nagamine Seisakusho, can be adopted.

The NA honeycomb is composed of platinum (Pt), palladium (Pd), etc., on the surface of a carrier mainly composed of calcium aluminate (CaO.Al ₂ O ₃ ), fused silica (SiO ₂ ) and titanium dioxide (TiO ₂ ). is a solid catalyst supporting a platinum group metal. Here, the carrier has a honeycomb shape, and the contact area of the platinum group metal supported on the carrier is very large, so that the oxidation reaction is caused efficiently.

In addition, the higher the temperature of the solid catalyst 108C, the faster the reaction speed of the catalytic combustion reaction in the solid catalyst 108C. Therefore, it is important to heat the solid catalyst 108C to a predetermined required temperature, and this heating can be performed, for example, by winding a heating wire around the solid catalyst 108C and energizing it. In another preferred embodiment, induction heating may be applied to the solid catalyst 108C. Specifically, iron (Fe) or an iron-based alloy such as stainless steel is mixed in the carrier of the solid catalyst 108C, and the solid catalyst 108C is subjected to an electromagnetic field generating device, for example, ten and several kilohertz. A magnetic field (electromagnetic field) of (kHz) to several hundred kHz is applied, and the solid catalyst 108C is directly heated with Joule heat due to eddy current generated by the principle of electromagnetic induction.

Here, in accordance with the skin effect of electromagnetic induction, near the surface of the carrier of the solid catalyst 108C, for example, inside the carrier at least at a depth equal to or greater than the permeation depth δ, iron powder, iron flakes, powdery or flaky stainless steel, etc. It is also preferable to disperse the iron-based alloy. As a result, the portion near the surface of the solid catalyst 108C to be heated can be heated to a predetermined high temperature with a uniform temperature distribution.

Alternatively, a plate piece of iron or an iron-based alloy such as stainless steel is placed in contact with, for example, the side surface of the solid catalyst 108C, and the solid catalyst 108C can be induction-heated via the plate piece by electromagnetic induction. . In any case, in the induction heating of the solid catalyst 108C, even when a plurality of solid catalysts 108Ca are used, for example, wiring such as a heating wire for each solid catalyst 108C is not required, and the plurality of solid catalysts 108C can be heated at once. Moreover, it can be easily heated. It is also preferable that at least part of the electric power required for heating by electric heating or electromagnetic induction as described above is supplied from the fuel cell 104 .

It is also preferable to use heat from the fuel cell 104 for heating the solid catalyst 108C as described above. Specifically, heat from the fuel cell 104 is transferred to the solid catalyst 108C of the catalytic combustion U 108 through a heat transfer means such as a heat exchanger or heat transfer system, and at least this heat is used to power the catalytic combustion. Heating of the solid catalyst 108C, which is necessary in some cases, may be performed.

For example, heat can be transferred directly by connecting the end of a heat exchanger, heat transfer system, or the like to the solid catalyst 108C. Alternatively, the gas reacting on the solid catalyst 108C may be heated with heat transferred through a heat exchanger, heat transfer system, or the like. Of course, such heating by heat from the fuel cell 104 may be actually performed in parallel with the above-described heating by electric heat or electromagnetic induction. In any event, the use of heat from the fuel cell 104 also allows for reduced or near-zero power consumption in the catalytic combustion U108.

Incidentally, in this embodiment, the oxygen concentration of the high-pressure exhaust gas used for catalytic combustion is, for example, about 0.5 to 10 vol%, and the reaction heat of catalytic combustion is a considerably large amount. It is not necessary to use a high temperature exceeding °C. Therefore, depending on the specifications of the high-purity nitrogen gas that is finally provided, the heat from the fuel cell 104 can cover most of the increase in temperature.

In addition, since the catalytic combustion reaction in the catalytic combustion U 108 is also affected by water vapor (H ₂ O) in the high pressure exhaust gas, there is a suitable water vapor content range for the introduced high pressure exhaust gas in which the catalytic combustion reaction rate increases. therefore,
(a) The temperature controller TCa adjusts the temperature of the high-pressure exhaust gas taken into the water exchange dehumidifier U105, and controls the relative humidity (water vapor content) of the high-pressure exhaust gas taken out of the water exchange dehumidifier U105 to a value within a predetermined range. or
(b) The pressure controller PCa adjusts the pressure of the high-pressure exhaust gas taken into (the dry filter 107F of) the dry filter U107, and the relative humidity (water vapor content) of the high-pressure exhaust gas taken out from the dry filter U107 is controlled within a predetermined range. It is also preferred to introduce a high pressure exhaust gas into the catalytic combustion U108 that is within the preferred water vapor content range, such as by controlling the value.

By the way, regarding the installation position of the catalytic combustion U108, if the high-pressure exhaust gas taken out from the water exchange dehumidifier U105 is a gas within the preferred water vapor content range, the catalytic combustion U108 should be installed in the preceding stage of the dry filtering U107. is also possible. Also in this regard, in embodiments that omit the dry filtering U107 as described above, the high pressure exhaust gas removed from the water exchange dehumidifier U105 and introduced into the catalytic combustion U108 is within the preferred water vapor content range or acceptable The operating condition is that the gas is within the water vapor content range.

Additionally, the oxygen-depleted exhaust gas delivered from the catalytic combustion U 108 will typically also contain residual hydrogen gas that has not been combusted in the catalytic combustion reaction. Therefore, a hydrogen gas filter (not shown) is provided immediately after the catalytic combustion U 108 to separate the residual hydrogen gas from the low oxygen concentration exhaust gas that has passed through the catalytic combustion U 108, and the hydrogen concentration is reduced or almost zero. It is also possible to output exhaust gas that has become Incidentally, as this hydrogen gas filter, for example, a filter having a palladium (Pd)-based hydrogen permeable membrane or a filter having an aromatic polyimide-based hydrogen gas separation membrane may be employed.

However, in this embodiment, the exhaust gas delivered from the catalytic combustion U108 is then subjected to a treatment in the nitrogen filtering U109 to filter not only the oxygen gas but also the hydrogen gas as described above, so that the hydrogen gas filter is provided Although it depends on the specifications required for the high-purity nitrogen gas to be used, it is basically unnecessary.

In addition, regarding the typical specifications of the high-purity nitrogen gas output from the catalytic combustion U108 described above, for example, the catalytic combustion U108, through the dry filtering U107, has an oxygen concentration of, for example, about 0.5 to about 10 vol%. and subjected to catalytic combustion treatment under high pressure (e.g., 9 atmospheres), the nitrogen gas finally provided from the catalytic combustion U 108 is converted to a high oxygen concentration, e.g., less than 1000 ppm vol (0.1 vol%). It is also possible to use pure nitrogen gas. Therefore, depending on the specifications required for the high-purity nitrogen gas provided, it is possible to omit the nitrogen filtering U109 and cover the oxygen concentration reduction process with the catalytic combustion U108.

Here, as another embodiment related to the installation position of the catalytic combustion U108, the catalytic combustion U108 can be provided in the rear stage of the nitrogen filtering U109. In this case as well, it is possible to subject the high-pressure exhaust gas (with increased nitrogen concentration) after nitrogen filtering to catalytic combustion, and finally output, for example, extremely high-purity (extremely low oxygen concentration) nitrogen gas. becomes.

However, in this case, the exhaust gas after the nitrogen filtering process already has a low oxygen concentration (for example, on the order of 100 ppm vol). As a result, hydrogen gas must be supplied to the exhaust gas in such an amount that the minute amount of oxygen gas in the exhaust gas can be used up and the amount of residual hydrogen gas must be minimized, requiring very advanced control. . In other words, in this case, since the nitrogen filtering process for filtering the hydrogen gas is not carried out after this, the remaining hydrogen gas must be suppressed as much as possible, and the control of the supply amount of the hydrogen gas must be very advanced. do not get

Also, in this case, the amount of oxygen gas is very small compared to general catalytic combustion, so the heat of reaction generated by catalytic combustion is extremely small. Therefore, it becomes necessary to heat the solid catalyst 109C to about 250° C., for example, in order to carry out effective catalytic combustion treatment, and as a result, the power consumption of the catalytic combustion U108 increases.

In contrast, the device configuration in which the catalytic combustion U108 is provided in the preceding stage of the nitrogen filtering U109 in this embodiment shown in FIG. problem) and the problem of reduction/removal of residual hydrogen gas (or the problem of hydrogen gas supply control during catalyst combustion) are solved or not caused.

Furthermore, the configuration of this device, in which the catalytic combustion U108 is provided before the nitrogen filtering U109, is a very suitable configuration from the viewpoint of the filtering effect (oxygen concentration reduction index) of the nitrogen gas filter 109F. First, as an index of the filtering effect, the oxygen concentration reduction index of the nitrogen gas filter 109F is calculated by the following equation (1) (oxygen concentration reduction index)=c_out_O2(Air)/c_out_O2
Define with In the above formula (1), c_out_O2 (Air) is the outlet oxygen concentration when air is introduced into the nitrogen gas filter 109F, and c_out_O2 is the effect (index) evaluation target gas introduced into the nitrogen gas filter 109F. This is the outlet oxygen concentration when

Here, as an experiment, a UBE N ₂ separator manufactured by Ube Industries was used as the nitrogen gas filter 109F, and under the conditions of an inlet pressure of 8 atmospheres (about 0.8 MPa) and an outlet flow rate of 2 L / min, the nitrogen gas filter 109F was subjected to catalyst When a nitrogen-oxygen mixed gas with an oxygen concentration of 1000 ppm vol (0.1 vol%), equivalent to the exhaust gas after catalytic combustion treatment in the combustion U108, was introduced, the oxygen concentration reduction index (filtering effect) was about 170. On the other hand, under the same conditions, when a nitrogen-oxygen mixed gas with an oxygen concentration of 5.1 vol%, which is equivalent to the exhaust gas immediately after being discharged from the fuel cell 104, was introduced, the oxygen concentration reduction index (filtering effect) was only about 6. .

In this way, by providing the catalytic combustion U108 in front of the nitrogen filtering U109 and introducing the exhaust gas after the catalytic combustion treatment to the nitrogen gas filter 109F, the catalytic combustion treatment (immediately after being discharged from the fuel cell 104) is performed. It is understood that an order of magnitude greater filtering effect (oxygen concentration reduction index) can be obtained as compared with the case where the exhaust gas is introduced without the exhaust gas. That is, by providing the catalytic combustion U108 before the nitrogen filtering U109 and greatly reducing the concentration of oxygen introduced to the nitrogen gas filter 109F in advance, it is possible to perform more efficient nitrogen filtering. of.

As described above, the high-pressure fuel cell 104, the dry filtering U107, the catalytic combustion U108, and the nitrogen filtering U109 form a high-pressure one-through system with respect to pressure (gas pressure). It is possible to efficiently remove the moisture and water vapor generated while promoting the efficiency of the process, and to further reduce the oxygen concentration in the exhaust gas. It has become. For example, using the pressure controller PCa, the pressure regulation unit PCb, the pressure controller PCe provided in the latter stage of the catalytic combustion U108, the pressure controller PCd, etc., 8 to 10 atmospheres (about 0.8 to 10 MPa) It may be controlled to maintain the exhaust gas pressure consistently.

Furthermore, the temperature adjuster TCa described above, the temperature adjuster TCc provided in the preceding stage of the catalytic combustion U 108, and the temperature adjuster TCb described above respectively control the temperature of the high-pressure exhaust gas extracted from the fuel cell 104, the catalytic combustion The temperature of the high pressure exhaust gas before it is taken into U108 and the temperature of the high pressure exhaust gas before it is taken into nitrogen filtering U109 to the "low temperature limit" required or determined in water exchange dehumidification U105, catalytic combustion U108, and nitrogen filtering U109. It is a means to control the temperature above the "temperature threshold" (eg 60°C, 80°C and 50°C) set based on the temperature. In other words, these temperature adjusters are means for adjusting the exhaust gas temperature throughout the entire device (system) 1 . For example, it may be adjusted to maintain a consistent exhaust gas temperature of 60-80°C.

Here, the temperature controller TCc, like the temperature controllers TCa and TCb, transfers heat from the fuel cell 104 (heat transferred by a heat transfer means such as a heat exchanger or a heat conduction system). It is also preferable to control the temperature of the high pressure exhaust gas to a temperature equal to or higher than the "temperature threshold".

[High pressure water electrolysis U125]
FIG. 5 is a schematic diagram showing still another embodiment of the nitrogen gas generator/system according to the present invention.

In the embodiment shown in FIG. 4, the nitrogen gas generator (system) 1 of the present embodiment shown in FIG. ) and the pressure booster U123 (FIG. 4) are replaced by a high-pressure water electrolysis U125 and a pressure regulation unit PCf. This high-pressure water electrolysis U125 electrolyzes a decomposition target that is water or steam supplied in a limited space (electrolysis cell) or a decomposition target that includes water or steam (the former in this embodiment), and is set High-pressure hydrogen generating means for generating high-pressure hydrogen gas having a pressure equal to or higher than the "pressure threshold".

Specifically, the high-pressure water electrolysis U 125 of this embodiment has a structure in which an ion-exchange membrane 125Ec such as a solid polymer membrane is sandwiched from both sides by a catalyst and electrodes (cathode 125Ea and anode 125Eb). It is equipped with a "high pressure water electrolyzer" 125E having a configuration. Of course, as the "high-pressure water electrolyzer" 125E, other various configurations and systems can be adopted as long as they can generate high-pressure hydrogen gas.

Here, the above "pressure threshold" is set to the same value as the "pressure threshold" set for the high pressure air generated by the high pressure gas supply U101 as described above. That is, the high pressure water electrolysis U 125 produces high pressure hydrogen gas at a sufficiently high pressure so that the produced hydrogen gas can ultimately be introduced into the fuel cell 104 at approximately the same high pressure as high pressure air. In this embodiment, the high-pressure water electrolysis U125 can also generate high-pressure hydrogen gas of, for example, several hundred atmospheres. In this case, the generated high-pressure hydrogen gas is decompressed to approximately the same pressure as the high-pressure air (eg, 3 to 10 atm) in a pressure regulation unit PCf having a buffer tank and a pressure regulation valve in the latter stage.

In addition, the high-pressure water electrolyzer 125E of the present embodiment generates high-temperature water or steam and electrolyzes it to generate high-pressure hydrogen gas in order to improve electrolysis efficiency (hydrogen generation efficiency). Here, the high pressure water electrolyser 125E receives heat transferred from the fuel cell U103 by heat transfer means such as a heat exchanger or heat transfer system, and at least uses this heat to produce hot water or steam. It is also preferable to increase the pressure of the hydrogen gas by raising the temperature in the electrolytic cell.

Further, the high-pressure water electrolyzer 125E receives the power generated by the fuel cell 104, and uses this power or this power and commercial power to perform electrolysis or produce hot water or steam (for example, by electrical heat). It is also preferable to generate Also, water (pure water) extracted from the drains Da and Db of the fuel cell U103 and the dry filter 107F of the dry filter U107 may be received from a collection and distribution pipe serving as water supply means, and this water may also be used as a raw material for electrolysis. preferable. In this way, the high-pressure water electrolyzer 125E receives and utilizes heat, power, and water from components in the device (system) 1 such as the fuel cell 104, thereby providing the device (system) 1 for electrolysis. It is also possible to greatly reduce the amount of heat, electric power and water to be supplied from outside.

Further, in this embodiment, it is also preferable that part of the high-pressure hydrogen gas generated by the high-pressure water electrolyzer 125E is taken out, for example, from the latter stage of the hydrogen mixer Ma and sent to the catalytic combustion U108. The catalytic combustion U108 utilizes the received high pressure hydrogen gas as fuel gas for catalytic combustion. As a result, the catalytic combustion U 108 can perform catalytic combustion processing without introducing fuel gas from the outside of the device (system) 1, for example.

Incidentally, in the high-pressure water electrolyzer 125E, the high-pressure oxygen gas generated together with the high-pressure hydrogen gas is preferably stored in, for example, an oxygen tank or supplied to the outside through a predetermined pipe.

As described above, the high-pressure water electrolysis U125 and the high-pressure fuel cell 104 form a series of high-pressure systems. can be produced and utilized in the fuel cell reaction at high pressure to support and promote the production of high-pressure exhaust gas, which is the source of high-purity nitrogen gas. In other words, both are a very suitable combination for producing nitrogen gas with high purity. Incidentally, even in the embodiment using the "normal gas pressure type" fuel cell 104, the above-described high-pressure water electrolysis U125 is adopted, and the generated high-pressure hydrogen gas can be decompressed, for example, and used as fuel gas. is. Alternatively, in this embodiment, non-high pressure water electrolysis means may be used to generate hydrogen gas as the fuel gas.

The high-pressure water electrolysis U125 has been described above, but the nitrogen gas generator (system) 1 uses the high-pressure water electrolysis U125 and the gas reforming U121 as high-pressure hydrogen generation means in order to secure various hydrogen supply sources. (and pressure booster U123) may also be provided. It is also possible to acquire the high pressure hydrogen gas itself from another system/apparatus instead of or together with these high pressure hydrogen generating means. Among these, the "natural energy power generation U127" that is preferably provided together with the "high-pressure water electrolysis U125" capable of easily generating high-pressure hydrogen will be described below.

Also referring to FIG. 5, the renewable energy generator U127 may be a solar power generation unit that includes solar cells and converts sunlight into electricity, where wind power rotates a rotor with blades to power a generator. It may be a wind power generation unit that drives and generates power, or a micro hydro power generation unit that drives a generator to generate power by rotating a turbine (water wheel) with water flow (hydropower).

In addition, various other power generation units can be employed as the natural energy power generation unit 127 as long as they can finally convert the light energy of sunlight or the kinetic energy of wind and water into electrical energy. Additionally, the renewable energy power generation unit 127 may be a combination of two or more of the power generation units as described above.

Furthermore, the natural energy power generation unit 127 of the present embodiment includes a storage battery 127B, which is a secondary battery such as a lithium (Li) battery or a lead (Pb) storage battery, for example. If so, the DC power is converted to DC power by a converter) and stored in the storage battery 127B.

Here, the natural energy power generation unit 127 of this embodiment includes a power generation amount meter that measures the amount of power generated by itself and a power storage amount meter that measures the amount of power stored in the storage battery 127B. It is measurable. In this embodiment, the overall control U131 confirms the measured amount of power generation and the amount of electricity stored, and then supplies power for high-pressure water electrolysis U125 that requires power for electrolysis from the storage battery 127B, and for high-pressure air generation. power is supplied to the high-pressure gas supply U101 that requires the power of . Here, of course, commercial power may also be supplied (to make up for the shortfall).

In any case, the combination of the natural energy power generation unit 127, the high-pressure water electrolysis U125, the fuel cell U103, and the catalytic combustion U108 described above produces high-purity nitrogen gas, carbon dioxide (CO ₂ ), etc. It is designed to generate and utilize hydrogen gas while minimizing greenhouse gas emissions. In other words, it greatly contributes to the realization of a carbon-neutral or carbon-free society.

[High Pressure Gas Supply U102: Gas Pressure Motor and Gas Compression Pump]
FIG. 6 is a schematic diagram showing another embodiment of the high-pressure gas supply means according to the present invention.

The high pressure gas supply U102 of the present embodiment shown in FIG. 6 comprises high pressure water electrolysis U125, the high pressure air employed in place of the high pressure gas supply U101 (FIG. 5) in the embodiment shown in FIG. It is a generating means.

Specifically, in this embodiment, the high pressure gas supply U102
(M1) a gas pressure motor 102M1 as gas pressure driving means for generating a driving force using the high pressure oxygen gas generated by the high pressure water electrolysis U125;
(P1) Gas that converts the taken air (gas containing nitrogen and oxygen) into high-pressure air (gas containing high-pressure nitrogen and oxygen) by the driving force (rotational force in this embodiment) received from the gas pressure motor 102M1 a compression pump 102P1 as compression means;
(M2) a gas pressure motor 102M2 as gas pressure driving means for generating a driving force using the high pressure hydrogen gas generated by the high pressure water electrolysis U125;
(P2) A gas that converts the taken air (gas containing nitrogen and oxygen) into high-pressure air (gas containing high-pressure nitrogen and oxygen) by driving force (rotational force in this embodiment) received from the gas pressure motor 102M2. and a compression pump 102P2 as compression means.

Incidentally, the high-pressure water electrolysis U125 of this embodiment is capable of generating high-pressure hydrogen gas of several tens to hundreds of atmospheres, and at the same time, it can generate high-pressure oxygen gas of several tens to hundreds of atmospheres. can be done. This high-pressure oxygen gas is first buffered in the oxygen tank TA1, and after the pressure and flow rate are adjusted by the pressure/flow controller provided at the tank outlet, it is introduced into the gas pressure motor 102M1. On the other hand, the high-pressure hydrogen gas is first buffered in the hydrogen tank TA2, adjusted in pressure and flow rate by a pressure/flow controller provided at the tank outlet, and introduced into the gas pressure motor 102M2.

Here, since the configurations of (M1) and (P1) and the configurations of (M2) and (P2) are similar in mechanism and operation mode, the above (M1) and (M1) and Only the configuration of (P1) will be described. The high-pressure gas supply U102 may have only the configurations (M1) and (P1) above, or only the configurations (M2) and (P2) above.

First, the gas pressure motor 102M1 has an eccentric rotor with a plurality of vanes (wing-shaped shutters) inside the outer shell of the main body. It flows into the space bounded by adjacent vanes between the shell and the eccentric rotor. The inflowing high-pressure oxygen gas expands, exerting a stronger pressure on one of the vanes, and as a result, rotates the eccentric rotor at high speed. As the eccentric rotor rotates, the expanded high-pressure air in the space weakens the total pressure on the vanes and is discharged from the main exhaust port and residual exhaust port. continued by a continuous influx of

The rotational force of this eccentric rotor is then transmitted to the compression pump 102P1 via the shaft of the eccentric rotor and a reduction gear mechanism on the way, and the compression pump 102P1 uses the received rotational force to extract air, for example, from the outside air. to produce high pressure air. The high-pressure air generated here is adjusted to a predetermined pressure (eg, 3 to 10 atmospheres) by the pressure controller PCg and the flow controller FCa and supplied to the water exchange dehumidifier U105.

Incidentally, the compression pump 102P1 can be a known compressor that uses rotational force. Alternatively, instead of the gas pressure motor 102M1, a gas pressure linear actuator may be employed as gas pressure driving means, and the driving force associated with the reciprocating motion of the high pressure oxygen gas may be transmitted to the compression pump 102P1. In this case, the compression pump 102P1 can be a known compressor that uses driving force associated with this reciprocating motion.

In this embodiment, the pressure of the compressed air generated by the compression pump 102P1 (compression pump 102P2) is controlled by the overall control U131 (FIG. 5), which monitors the pressure with the pressure controller PCg (pressure controller PCh). By controlling the pressure and flow rate of high-pressure oxygen gas (high-pressure hydrogen gas) introduced from the oxygen tank TA1 (hydrogen tank TA2) to the gas pressure motor 102M1 (gas pressure motor 102M2), it is adjusted and set to a desired value.

In addition, the high-pressure oxygen gas discharged from the main exhaust port and the remaining amount exhaust port of the gas pressure motor 102M1 may be collected and then stored, for example, in an oxygen tank or supplied to the outside via a predetermined pipe. preferable. Furthermore, regarding the configurations of (M2) and (P2) above, the high-pressure hydrogen gas discharged from the main exhaust port and the remaining amount exhaust port of the gas pressure motor 102M2 in the same manner as described above is controlled by the flow controller FCb. is adjusted to a predetermined flow rate and pressure (for example, 3 to 10 atmospheres) and supplied to the fuel cell U103 as a fuel gas.

As explained above, the high pressure gas supply U102 utilizes the physical energy of the high pressure gas supplied from the high pressure water electrolysis U125 to generate high pressure air. Therefore, unlike typical compressors (using electric motors) that consume considerable power, power consumption during high pressure air generation can be reduced to approximately zero. As a result, it is also possible to provide more of the electric power generated by the fuel cell U103 to the outside without using it for high-pressure air generation.

[Another embodiment of the fuel cell U103]
FIG. 7 is a schematic diagram for explaining another embodiment of the fuel cell U according to the invention.

The fuel cell U103 of this embodiment shown in FIG. 7 has a fuel cell 104 and controllers 103Ca, 103Cb and 103Cc. Among them, the fuel cell 104 includes a plurality of cells, which are structural units including a hydrogen electrode and an air electrode with an electrolyte layer interposed therebetween. These cells are stacked so that hydrogen (fuel gas) and air (gas containing nitrogen and oxygen) pass through the hydrogen and air electrodes in the cells in order from the fuel supply upper cell to the lower cell. is designed to

Further, the plurality of cells are divided into a plurality of functional cell portions, namely, a power generation priority cell portion 104a, an intermediate cell portion 103b, and an oxygen removal cell portion 103 in FIG. Each of these functional cell sections (104a, 104b, 104c) includes one or a plurality of consecutive (two or three in FIG. 7, in practice, for example, several to several hundred) cells, In addition, they are not electrically connected in series with other functional cell units, but are electrically connected to individually provided power generation amount control units (103Ca, 103Cb, 103Cc).

Here, as shown in FIG. 7, the control units 103Ca, 103Cb, and 103Cc respectively control the electromotive force generated between the hydrogen electrode and the air electrode in the power generation priority cell unit 104a, the intermediate cell unit 104b, and the oxygen removal cell unit 104c. It receives the power and outputs the electric power that matches the functional cell unit in charge. Also, at this time, it is preferable to measure the complex impedance of the functional cell unit in charge and perform control and management in accordance with the functional cell unit.

In contrast to the fuel cell 104 of this embodiment, conventional fuel cells, particularly PEFC fuel cells, typically have an electromotive force of less than 1 V (volt) per cell. In order to ensure the Here, the amount of power generation that can be generated is naturally small in the lower stage cells with a small amount of oxygen supply, but the power generation efficiency (with respect to the amount of hydrogen supply) in the entire cells connected in series including such cells is Since it is necessary to equalize the amount of power generated by each cell to some extent, it will be considerably damaged.

In contrast, in the fuel cell 104 of this embodiment,
(a) the power generation priority cell section 104a with a large amount of oxygen supply (oxygen in the supplied air is not yet consumed so much);
(b) an intermediate cell portion 104b that is intermediate in terms of oxygen supply;
(c) The oxygen-removing cell section 104c with a small amount of oxygen supply (a considerable amount of oxygen in the supplied air is consumed) can individually receive power generation amount control suitable for the oxygen supply amount.

Moreover, by performing such power generation amount control, it is possible to maximize or improve both the oxygen reduction efficiency and the power generation efficiency (relative to the hydrogen supply amount) in the fuel cell 104 . Furthermore, by controlling the power generation amount in each control unit (103Ca, 103Cb, 103Cc) together, it is also possible to adjust the oxygen concentration (outlet oxygen concentration) of the exhaust gas finally discharged to a desired value. It becomes.

Thus, the fuel cell 104 of this embodiment is a very suitable fuel cell for generating high-purity nitrogen gas. Here, of course, this fuel cell 104 may also be used for other general purposes as a suitable fuel cell to allow for optimization of power generation efficiency.

Incidentally, the number of functional cell units in the fuel cell 104 of this embodiment is of course not limited to three, and may be two or four or more. For example, it is possible to use a group of 150 lower cells and a group of remaining upper cells among hundreds of cells as the first functional cell section and the second functional cell section, respectively.

[Overall control unit 131]
The overall control unit 131 shown in FIGS. 1, 4 and 5 will now be described. The control of the overall control unit 131 shown in FIG. 5 will be described below. This also applies to section 131 .

The overall control unit 131 shown in FIG.
(a) high pressure air generation process in high pressure gas supply U101;
(b) high-pressure hydrogen generation treatment in high-pressure water electrolysis U125;
(c) high-pressure exhaust gas generation process in the fuel cell U103;
(d) high-pressure exhaust gas dehumidification treatment in water exchange dehumidification U105;
(e) High-pressure exhaust gas dehumidification treatment in dry filtering U107,
(f) the high-pressure exhaust gas deoxygenation process in the catalytic combustion U108; and (g) the high-purity nitrogen gas generation process in the nitrogen filtering U109.

Specifically, the overall control unit 131 of the present embodiment connects each of the above units (a) to (g), various instruments and devices provided in or before and after the unit, and a wired or wireless communication network. Based on the measurement data from the various instruments/devices, it transmits control/adjustment instructions to the above units (a) to (g) and the various instruments/devices, Each process of (a) to (g) is controlled and executed.

In this embodiment, the overall control unit 131 includes a processor and a memory, and the memory stores and loads a processing control program for controlling each of the above processes (a) to (g). Then, this processing control program is executed by this processor. Further, as a preferred embodiment, the processing control program uses a machine learning model for processing control, such as DNN (Deep Neural Network) algorithm may be used to execute control processing.

In particular, the general control unit 131 of the present embodiment treats the fuel cell 104, dry filtering U107, catalytic combustion U108, and nitrogen filtering U109 as a high pressure one-through system with respect to pressure (gas pressure), Using the process control program of, pressure controller PCa, pressure regulation unit PCb, pressure controller PCd, and It is also preferable to transmit pressure (flow rate) control/adjustment instructions to the flow controller FCc or the like.

Furthermore, the overall control unit 131 of the present embodiment also uses the above process control program to control the temperature controllers TCa, TCc, and a temperature control/adjustment instruction to the temperature controller TCb or the like.

Furthermore, the overall control unit 131 monitors the (outlet) oxygen concentration of the high-pressure exhaust gas taken from the fuel cell U103, the catalytic combustion U108, and the nitrogen filtering U109 (with an oximeter installed at the relevant location), and finally It is also preferable to control the oxygen concentration of the high-purity nitrogen gas supplied to to be less than a predetermined upper limit determined by the required specifications.

Specifically, in this case, the overall control unit 131, for example, similarly uses the above process control program to
(a) In the case where the fuel cell U103 (fuel cell 104) is the one shown in FIG. Sending a power generation amount control/adjustment instruction to the effect that the power generation amount is set to a predetermined value,
(b) In order to control the reduction in oxygen concentration due to the catalytic combustion process in the catalytic combustion U 108, send a catalyst temperature control/adjustment instruction to the catalytic combustion U 108 to adjust the heat treatment (heating temperature) of the solid catalyst 108C. or
(c) Flow rate/pressure control/adjustment for the flow controller FCc to set the outlet flow rate and outlet pressure of the nitrogen filtering U109 to predetermined values in order to control the oxygen concentration reduction due to the nitrogen filtering process in the nitrogen filtering U109 By sending instructions, it is possible to control and adjust the oxygen concentration in the exhaust gas taken out from each unit.

As described in detail above, according to the present invention, high-purity nitrogen gas can be reliably and stably generated by subjecting exhaust gas from a fuel cell to water exchange dehumidification treatment and nitrogen filtering treatment. It becomes possible. In addition, although it is one embodiment, it is also possible to more reliably, more stably, and efficiently generate nitrogen gas of higher purity by using catalytic combustion processing.

In the future, when a hydrogen gas society or a zero carbon society arrives, it is thought that the use of fuel cells using hydrogen gas as fuel gas will spread widely everywhere. The present invention will greatly contribute to the efficient production of nitrogen gas in such times. Of course, it is also possible to meet the needs for supplying power, heat, and even pure water in some cases, on the spot.

In other words, it is believed that the present invention will also contribute to building a local production for local consumption type carbon zero energy and product supply and demand system, which is regarded as one of the ideal forms of the future. Furthermore, it is thought that it will be of great help in achieving carbon neutrality, which is an urgent issue.

Furthermore, although this is also just one embodiment of the present invention, it is also possible to supply hydrogen gas as fuel gas to the fuel cell by using high-pressure electrolysis means. Such a configuration is also considered to be widely used in the above-mentioned hydrogen gas society and carbon zero society.

It should be noted that all of the above-described embodiments are illustrative of the present invention and not restrictive, and the present invention can be implemented in various other variations and modifications. Accordingly, the scope of the invention is to be defined only by the claims and their equivalents.

1 Nitrogen gas generator/system 101, 102 High-pressure gas supply unit (U)
102M1, 102M2 Gas pressure motor 102P1, 102P2 Compression pump 103 Fuel cell U
103Ca, 103Cb, 103Cc control section 104 fuel cell 104C pressure vessel 104E electrolyte layer 104G heat exchange section 104H fuel gas chamber 104P pressure regulator in vessel 104Pa pressure gauge 104S cell stack 104X oxidizing gas chamber 105 water exchange dehumidification U
105D Dehumidification chamber 105H Humidification chamber 105V Water vapor exchange membrane 107 Dry filtering U
107F Dry filter 108 Catalytic combustion U
108C solid catalyst 109 nitrogen filtering U
109F, 109F1, 109F2, 109F3 Nitrogen gas filter 109Fa Hollow fiber fiber portion 109Fb Filter inlet portion 109Fc Filter outlet portion 109Fd Filter purge portion 121 Gas reforming U
123 Boost U
125 High pressure water electrolysis U
125E High pressure water electrolyzer 125Ea Cathode 125Eb Anode 125Ec Ion exchange membrane 127 Natural energy power generation U
127B storage battery 129 hydrogen recovery U
131 overall control U

Claims (17)

a fuel cell that operates by taking in air or a gas containing nitrogen and oxygen and a fuel gas;
Exchanging water between the exhaust gas having an oxygen concentration lower than that of the air taken out from the fuel cell and the air or the gas containing nitrogen and oxygen taken into the fuel cell, and water or water vapor in the exhaust gas a water exchange dehumidifying means for reducing the
A nitrogen gas generator, comprising filters having different degrees of permeation of nitrogen and oxygen, and nitrogen filtering means for converting the exhaust gas with reduced moisture or water vapor content into gas with increased nitrogen concentration. A high-pressure gas supply capable of supplying to the fuel cell high-pressure air or high-pressure gas containing nitrogen and oxygen having a pressure equal to or higher than a pressure threshold set based on at least the lower limit pressure requested or determined by the nitrogen filtering means. further comprising means;
The water exchange dehumidifying means reduces the moisture or water vapor content in the high-pressure exhaust gas having a pressure equal to or higher than the pressure threshold,
2. The nitrogen gas generator according to claim 1, wherein said nitrogen filtering means converts said high-pressure exhaust gas with reduced moisture or water vapor content into gas with increased nitrogen concentration. further comprising a dry filtering means equipped with a dry filter for further reducing moisture or water vapor content in the high-pressure exhaust gas taken out from the water exchange dehumidifying means;
3. The nitrogen gas generator according to claim 2, wherein said pressure threshold value is also set based on the lower limit pressure requested or determined by said dry filtering means. The high-pressure exhaust gas having reduced moisture or water vapor content before being taken into the nitrogen filtering means is reacted with the fuel gas on a combustion catalyst, or the nitrogen concentration increased extracted from the nitrogen filtering means. 4. The method further comprises catalytic combustion means for causing the gas and the fuel gas to react on a combustion catalyst to further reduce the oxygen concentration in the high-pressure exhaust gas or the nitrogen-enriched gas. Nitrogen gas generator according to . It further comprises high-pressure electrolysis means for electrolyzing a decomposition target that is water or steam or a decomposition target containing water or steam supplied in a limited space to generate high-pressure hydrogen gas having a pressure equal to or higher than the pressure threshold. death,
5. The fuel cell according to any one of claims 2 to 4, wherein the high-pressure hydrogen gas and the high-pressure air or the high-pressure gas containing nitrogen and oxygen are taken in, and the high-pressure exhaust gas is discharged. 1. The nitrogen gas generator according to claim 1. 6. The apparatus according to claim 5, further comprising heat transfer means for transferring heat from said fuel cell to said high pressure electrolysis means and using at least said heat to generate said high pressure hydrogen gas. nitrogen gas generator. dry filtering means comprising a dry filter for further reducing the moisture or water vapor content in the high pressure exhaust gas removed from the water exchange dehumidification means;
6. A water supplying means for supplying water from said dry filtering means, or water from said dry filtering means and said fuel cell, to said high pressure electrolyzing means as said decomposition target. 7. The nitrogen gas generator according to 6. The high-pressure exhaust gas having reduced moisture or water vapor content before being taken into the nitrogen filtering means is reacted with the fuel gas on a combustion catalyst, or the nitrogen concentration increased extracted from the nitrogen filtering means. further comprising catalytic combustion means for causing the gas and the fuel gas to react on a combustion catalyst to further reduce the oxygen concentration in the high-pressure exhaust gas or the nitrogen-enriched gas;
8. The nitrogen gas generator according to any one of claims 5 to 7, wherein the catalytic combustion means uses at least the generated high-pressure hydrogen gas as the fuel gas used for catalytic combustion. The high pressure gas supply means is
gas pressure driving means for generating a driving force using the generated high-pressure hydrogen gas and/or the high-pressure oxygen gas having a pressure equal to or higher than the pressure threshold value generated by the high-pressure electrolysis means;
gas compression means for converting the air or the gas containing nitrogen and oxygen into the high-pressure air or the high-pressure gas containing nitrogen and oxygen by the received driving force. 9. The nitrogen gas generator according to any one of 5 to 8. It further comprises heat transfer means for transferring heat from the fuel cell to the catalytic combustion means and using at least the heat to heat the combustion catalyst required for catalytic combustion. The nitrogen gas generator according to claim 4 or 8. a pressure adjusting means for converting the exhaust gas taken out from the water exchange dehumidifying means into a high-pressure exhaust gas having a pressure equal to or higher than a pressure threshold set based on at least the lower limit pressure required or determined by the nitrogen filtering means;
5. The nitrogen gas generator according to claim 1 or 4, further comprising dry filtering means having a dry filter for further reducing moisture or water vapor content in the high-pressure exhaust gas taken out from the pressure adjusting means. Device. 12. The nitrogen gas generator according to any one of claims 2 to 11, wherein the lower limit pressure is set to a pressure value of at least 3 atmospheres or higher. a lower limit required or determined by the water exchange dehumidifying means and/or the nitrogen filtering means for the temperature of the exhaust gas taken out from the fuel cell and/or the temperature of the exhaust gas before being taken into the nitrogen filtering means; 13. The nitrogen gas generator according to any one of claims 1 to 12, further comprising temperature adjusting means for adjusting the temperature to a temperature equal to or higher than a temperature threshold set based on the temperature. 14. The nitrogen gas generator according to claim 13, wherein the temperature adjustment means uses heat from the fuel cell to control the temperature of the exhaust gas to a temperature equal to or higher than the temperature threshold. The fuel cell includes a plurality of cells, which are structural units each including two electrodes with an electrolyte interposed therebetween. 15. The generator according to claim 1, comprising one or a plurality of continuous cells, not electrically connected in series with other functional cell units, but electrically connected to an individual power generation amount control unit. The nitrogen gas generator according to any one of claims 1 to 3. a fuel cell that operates by taking in air or a gas containing nitrogen and oxygen and a fuel gas;
Exchanging water between the exhaust gas having an oxygen concentration lower than that of the air taken out from the fuel cell and the air or the gas containing nitrogen and oxygen taken into the fuel cell, and water or water vapor in the exhaust gas a water exchange dehumidifying means for reducing the
A nitrogen gas generating system, comprising filters having different degrees of permeation of nitrogen and oxygen, and nitrogen filtering means for converting the exhaust gas with reduced moisture or water vapor content into gas with increased nitrogen concentration. supplying air or a gas containing nitrogen and oxygen and a fuel gas to the fuel cell to operate the fuel cell;
Exchanging water between the exhaust gas having an oxygen concentration lower than that of the air taken out from the fuel cell and the air or the gas containing nitrogen and oxygen taken into the fuel cell, and water or water vapor in the exhaust gas reducing the minute;
and a step of causing the exhaust gas with reduced moisture or water vapor content to act on filters having different degrees of permeation for nitrogen and oxygen, and extracting the exhaust gas with increased nitrogen concentration from the filter. Gas generation method.

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