JP6707356B2 - Respiratory air regenerating apparatus and regenerating method - Google Patents

Description

The present invention relates to a device for regenerating breathing air for humans in a closed space or a space kept closed.

Respiratory air in a closed space or a space kept closed is first consumed primarily by a decrease in oxygen content due to the presence of humans or animals. Quantitative data for this are described, for example, by K. Kunsch and S. Kunsch in "Human in Number" (Der Mensch in Zahlen), Spectrum Akademischer Verlag, Heidelberg (2000). The result of exhausting breathing air is fatigue, headaches and similar symptoms, which lead to diminished concentration, especially in humans.

In densely populated areas (especially in Asia), air is severely polluted, at least in certain weather conditions, and it is only suitable as breathing air for humans. Therefore, in vehicles and also in buildings, opening windows is often avoided, which prevents polluted air from reaching the interior space as much as possible.

It is nevertheless possible to filter the breathing air for ventilation with the surrounding environment. The filter system can bind particulates and, to a limited extent, gaseous pollutants. However, it is often advantageous for the quality of breathing air in the interior space of a building or vehicle if the polluted air reaches the interior space as little as possible.

If the direct exchange of the breathing air with the air in the external space is completely or significantly stopped due to contamination, the oxygen concentration is kept at about 21%. This is possible, for example, with oxygen from an oxygen cylinder.

One known option for chemically forming pure oxygen is to electrolyze water into hydrogen and oxygen using a water electrolyzer. This reaction requires a large amount of energy, and explosive hydrogen gas is generated.

The "oxygen bar" is widely known in smog areas (eg, Los Angeles, Tokyo), where it can be refreshed by inhaling a large amount of oxygen.

Another possible phase of breathing air consumed in enclosed spaces is an increase in the concentration of carbon dioxide.

To remove carbon dioxide from the atmosphere, for example, the APS report "Direct Air Capture of CO2 with Chemicals" (2011), and also Energy Procedia 37, pp. 6079-6095, discuss a series of related reactions. However, this is discussed here in terms of limiting the increase in CO ₂ content in the Earth's atmosphere as a whole.

Another aspect of the breathing air consumed is the increased content of water vapor. There are various options in the prior art for removing water vapor from air. The simplest is a cold trap.

"Human in Number" by K. Kunsch and S. Kunsch (Der Mensch in Zahlen), Spectrum Akademischer Verlag, Heidelberg 2000) APS Report "Direct Air Capture of CO2 with Chemicals" (2011) Energy Procedia 37, pp. 6079-6095

According to a first aspect, the invention is directed to a method of regenerating human breathing air in a closed space or a space to be kept closed. Here, this space has a wall that separates the air in the external space, which is contaminated especially by odors, harmful substances, or other causes, from the breathing air in the internal space. And the above method
Withdrawing air from the external space,
The oxygen of the air from the external space supplies this air to the chemical reactions involved as reaction partners;
Carrying out this chemical reaction,
Supplying the reaction product of this chemical reaction to an inverse chemical reaction,
Performing this inverse chemical reaction,
A step of releasing oxygen generated during this reverse chemical reaction into the internal space;
Supplying the reaction product of the reverse chemical reaction to the chemical reaction as another reaction partner of the chemical reaction.

It is understood here that two chemical reactions are inverse reactions of one another when they can proceed in two directions depending on external conditions (eg temperature, energy supply and catalyst). For example, it is considered that the oxidation of hydrogen by discharging electric power in a fuel cell and the electrolysis of water in a water electrolyzer into hydrogen and oxygen are opposite to each other.

The specific energy inputs for the reaction and the counter-reaction cancel each other out (ignoring unavoidable losses) so that the two reactions can be run together in a closed cycle. Thus, in one advantageous embodiment, the following reaction pairs can also be used: That is, the energy required for the individual reactions that form oxygen can be unacceptably large, and, for example, a pair of reactions in which the vehicle-mounted power supply network can be overloaded as the energy supply side in a vehicle can also be used. Of.

For example, the chemical reaction can utilize the oxidation of hydrogen to water by oxygen obtained from the air from the outside space in the fuel cell.

In another variant, the electrolysis of water by a water electrolyzer is used as an inverse chemical reaction. Here, it is advantageous if most of the required energy of this electrolyzer is covered by the fuel cell.

In another embodiment of the invention, the carbon dioxide that builds up in the breathing air in the interior space can be removed by another step. This has the advantage that the regeneration of breathing air can be used for a relatively long time. With the increasing concentration of carbon dioxide, the use of breathing air with oxygen is no longer restricted.

The removal of carbon dioxide can consist of several sub-steps, the first sub-step being able to direct breathing air through a liquid containing sodium hydroxide, which forms sodium carbonate in this solution. It This liquid can be regenerated in the second substep by adding a water-rich calcium hydroxide solution, where calcium carbonate is formed in addition to sodium hydroxide, which calcium carbonate precipitates and is filtered off. Can be removed by. Calcium carbonate here contains carbon dioxide in bound form, and the calcium carbonate itself can be decomposed by heating into calcium oxide and carbon dioxide released to the external space. Finally this calcium oxide is dissolved in water. Here, the calcium hydroxide required for the regeneration of sodium hydroxide is obtained. Advantageously, these reactions proceed in a closed cycle.

It is further advantageous to transfer the exhaust heat of the fuel cell to calcium carbonate to be heated in a separate step. This results in a particularly low energy consumption in this embodiment.

In another embodiment of the invention, the water contained in the breathing air in the interior space can be removed in a separate step. This is done, for example, using a cold trap. The advantage of this embodiment is that it ensures that in the vehicle the windows are not fogged by the passenger's moist breathing air.

Another aspect of the invention is a device for regenerating breathing air in a closed space or a space to be kept closed, the device comprising an air inlet from an external space and an internal space. With an oxygen outlet to the space. The apparatus includes a first apparatus configured to carry out a chemical reaction and having an air inlet connected to the external space, the apparatus including a reverse chemical reaction. Further included is a second device configured and having an oxygen outlet connected to the interior space, the device including a carrier line connecting the first and second devices to each other. There is.

Advantageously, such a device is capable of increasing oxygen in the interior space.

In one embodiment,
The first device for carrying out a chemical reaction is a fuel cell which is configured to electrochemically oxidize hydrogen into water and whose air inlet is connected to the external space and which carries out a reverse chemical reaction. The second device is a water electrolyzer that is configured to electrochemically decompose water into oxygen and hydrogen and has its oxygen outlet connected to the internal space. A hydrogen carrier line connecting the electrolyzer and the fuel cell and a water carrier line connecting the fuel cell and the water electrolyzer are included.

Advantageously, the device forms a closed cycle.

An alternative embodiment of this device may include a third device configured to separate carbon dioxide from the breathing air in the interior space, whereby in an advantageous manner the increase of carbon dioxide causes the device to The use of is not restricted.

Another embodiment of the above device may include a fourth device configured to separate water vapor from the breathing air within the interior space. This advantageously prevents fogging of the cold window glass.

FIG. 3 illustrates an apparatus for regenerating breathing air according to one embodiment of the invention. FIG. 3 shows a sequence of steps of a method of regenerating breathing air according to the embodiment shown in FIG. 1 of the present invention. FIG. 6 shows another step of a method of regenerating breathing air according to another embodiment of the invention.

Other features and advantages of the present invention will result from the following description taken in conjunction with the accompanying drawings.

As shown in FIG. 1, there are a plurality of persons 13 in, for example, a passenger car or a conference room in a closed or closed space. These humans have a limited amount of breathing air in this space. The present invention deals with the case where the air in the external space is contaminated by odors, harmful substances, or for other reasons. The wall of this space is shown in FIG. 1 by the reference numeral 1, which separates an internal space 2 with a person 13 and an external space 3 with contaminated air.

In the breathing air in the internal space 2, the oxygen content is lowered due to the presence of the human 13, so that the breathing air in the internal space 2 is regenerated.

For this purpose, a chemical reaction with oxygen is carried out, in which oxygen from the air in the external space 3 is used via the air passages 6 and subsequently a reverse chemical reaction is carried out in which gaseous oxygen is carried out. Are released again and supplied to the internal space 2 via the oxygen outlet 7.

If the two reactions proceed in a closed cycle, the respective chemical intermediate product (possibly in highly pure form) can occur in the amounts necessary as starting material for each of the other reactions.

A portion of the energy required for one reaction can be supplemented by the energy released by another reaction. However, the losses that are unavoidable according to the second law of thermodynamics remain at least to a certain extent, and substantial efficiencies generally do not reach theoretically possible efficiencies.

This makes it possible to assemble a compact device, which essentially requires only an energy supply in addition to the air inlet 6 for polluted air and the oxygen outlet 7 for pure oxygen. For example, in the case of a person 13 in a vehicle, this energy can be extracted from the vehicle-mounted power supply network 12 in the form of electrical energy.

In one embodiment, the above-mentioned reverse chemical reaction in which oxygen is formed is electrolysis of water in the water electrolyzer 5. That is,
2H ₂ O + electric energy → 2H ₂ + O ₂
Is.

The fuel cell 4 can be used as a chemical reaction to supply most of this electric energy. Oxygen in the air from the external space 3 is used here and is reacted with hydrogen formed in the electrolyzer to become water. That is,
2H ₂ +O ₂ →2H ₂ O+electrical energy.

For material transport, firstly a hydrogen carrier line 9 from the water electrolyzer 5 to the fuel cell 4 can be provided. An intermediate reservoir of hydrogen is not needed in this embodiment, and the device only receives hydrogen from the hydrogen carrier line 9 and the reaction cells (fuel cell 4 and water electrolyzer 5) at any one time. As a result, the device impairs the operational safety of the vehicle in which it is installed to a correspondingly small extent, for example in the event of an accident.

Secondly, a water carrier pipe 8 can be provided, and the high purity DI water (deionized water) formed in the fuel cell 4 is supplied to the water electrolyzer 5 by the water carrier pipe 8. The deionized water replaces the water that is decomposed in the water electrolyzer. It is also possible here to provide an intermediate reservoir 15 for DI water, which can optionally replace volatile water.

The result of the estimation for the energy required to operate the device of this embodiment is that the power consumption per person (oxygen consumption: 0.3 liter/m) is about 80 W when the efficiency of the fuel cell 4 is 60%. Must be supplied to this device. This is perfectly tolerable, for example, for on-board power supply networks of passenger cars, but also, for example, in conference rooms with a correspondingly large number of people.

In a simpler embodiment for a vehicle with a fuel drive, the electrolysis with the water electrolyzer 5 can be combined with the at least partial combustion of the hydrogen produced here in the engine.

The oxygen content of breathing air should be 21%. The operation of the device can thus be controlled accordingly by the oximeter. As an alternative, the number of people currently in the interior space 2 can be adjusted in each of the above-mentioned devices or can be automatically identified by this device. In passenger cars, for example, it is also possible to make use of the monitoring of the use of safety belts, which are provided in any case.

The device of the form described above is also suitable for use as an "oxygen shower", by means of which the driver of a passenger car can be refreshed.

The device for regenerating the breathing air described thus far can only be used for a limited time, for example about 30 minutes in a passenger car in which the interior space 2 has a volume of about 4 m ³ and two people are seated. This is because the breathing of the human 13 also releases carbon dioxide (CO ₂ ) to the internal space 2. Carbon dioxide causes fatigue and can be dangerous if the concentration is high. Therefore, the CO ₂ concentration in the internal space 2 is monitored. A value of 0.5% by volume of CO ₂ is the maximum acceptable workplace concentration. If this is exceeded at the latest, CO ₂ is removed from the internal space 2 by means of the device 10 provided for this purpose. For this purpose, a CO ₂ sensor 14 can be provided, whose measured value controls the amount of CO ₂ to be removed.

A conservative estimate of the energy required to remove 0.3 liters/minute of CO ₂ per person yields about 14 W of power and about 60 W of heat output. Here, the exhaust heat of the fuel cell for oxygen treatment can be used as the heat energy. In vehicles, it is also possible to use the exhaust heat of the engine.

A feature of another embodiment of the present invention is that the apparatus described above includes an apparatus for removing water vapor from respiratory air in an interior space. This is because humans release a large amount of water vapor to the surroundings in addition to carbon dioxide in an enclosed space. Especially in a vehicle, when the dew point exceeds the temperature of the window glass, especially when the outside air temperature is low, the window glass may become cloudy because the amount of water in the inner space 2 is greatly increased. In order to keep the temperature inside the interior space 2 constant and to lower the dew point, a device 11 suitable for this purpose can remove water from the breathing air inside the interior space 2 using, for example, a cold trap.

FIG. 2 shows a possible sequence of steps in regenerating human breathing air in a closed or closed space, which space has a wall 1. By this wall, the contaminated air in the external space 3 and the breathing air for the human 13 in the internal space 2 are kept in a separated state.

The method starts with a step 21 of withdrawing air from the external space 3, followed by a step 22 of supplying this air to a chemical reaction 23 and a step of carrying out the chemical reaction 23. In the chemical reaction 23, oxygen of the air obtained from the external space 3 participates as a reaction partner. Subsequently, step 24 of supplying the reaction product of the chemical reaction 23 to the reverse chemical reaction 25 and its execution follow. Next, a step 26 of releasing oxygen generated during the reverse chemical reaction to the internal space 2, and a step of supplying the reaction product of the reverse chemical reaction 25 to the chemical reaction 23 as another reaction partner of the chemical reaction. 27 and so on.

In one embodiment, the chemical reaction 23 may be the oxidation of hydrogen to water in the fuel cell 4 and the reverse reaction 25 may be the electrolysis of water to oxygen and hydrogen.

In another embodiment shown in FIG. 3, a step 31 of removing carbon dioxide from the breathing air in the interior space 2 can be added.

In one embodiment, step 31 of removing carbon dioxide from the breathing air in interior space 2 includes:
Sub-step 32 of directing breathing air through a solution containing sodium hydroxide;
A sub-step 33 of regenerating this solution by adding calcium oxide, in which calcium carbonate is formed,
A sub-step 34 of decomposing calcium carbonate into calcium oxide and carbon dioxide by heating;
A sub-step 35 of releasing carbon dioxide to the air in the external space 3,
Sub-step 36 of dissolving calcium carbonate in water,
Substep 37 of returning calcium hydroxide to substep 33 of regeneration.

In another embodiment, where the chemical reaction 23 is the oxidation of hydrogen to water in the fuel cell 4, another substep may include the step 38 of transporting the fuel cell exhaust heat to calcium carbonate.

Another embodiment may include removing water vapor from the breathing air within the interior space 2.

1 Wall, 2 Internal Space, 3 External Space, 4 Fuel Cell, 5 Water Electrolyzer, 6 Air Passage, 7 Oxygen Outlet, 8 Water Transport Pipeline, 9 Hydrogen Transport Pipeline, 10 CO ₂ Removal Device, 11 Water Removal Device, 12 In-vehicle power supply network, 13 Human, 14 CO ₂ sensor, 15 Intermediate reservoir

Claims (6)

A method of regenerating breathing air for humans in a space which is to be closed or kept closed.
In the method, the space has a wall (1), whereby the air in the external space (3) and the breathing air in the internal space (2) are kept separated by the wall.
The method is
Withdrawing air from the external space (3) (21),
A step (22) in which oxygen of the air from the external space (3) supplies the air to a chemical reaction (23) involved as a reaction partner;
Performing the chemical reaction (23);
Supplying (24) the reaction product of the chemical reaction (23) to the reverse chemical reaction (25);
Performing the inverse chemical reaction (25),
Releasing (26) oxygen generated during the reverse chemical reaction (25) into the internal space (2);
Supplying the reaction product of the reverse chemical reaction (25) to the chemical reaction (23) as another reaction partner of the chemical reaction (23) (27) ,
Removing (31) carbon dioxide from the breathing air in the interior space (2);
Have a,
The chemical reaction (23) is the oxidation of hydrogen to water in the fuel cell (4),
The inverse chemical reaction (25) is the electrolysis of water into oxygen and hydrogen,
The step (31) of removing the carbon dioxide comprises
A sub-step (32) of directing said breathing air to a solution containing sodium hydroxide;
A sub-step of regenerating the solution by adding calcium hydroxide, wherein calcium carbonate is formed (33),
A substep (34) of decomposing the calcium carbonate into calcium oxide and carbon dioxide by heating,
A sub-step (35) of releasing the carbon dioxide into the air of the external space (3);
A substep (36) of dissolving the calcium oxide in water,
A substep (37) of returning the calcium hydroxide to the substep (33) of regenerating,
A sub-step (38) of carrying exhaust heat of the fuel cell (4) to the sub-step (34) of decomposing the calcium carbonate,
Wherein the <br/> to have. Having another step of removing water vapor from the breathing air in the interior space (2),
The method of claim 1 . Use a cold trap,
The method of claim 2 . A device for regenerating breathing air in a closed space or a space to be kept closed, comprising:
A wall (1) separates the interior space (2) containing the breathing air from the exterior space (3), the device comprising:
A fuel cell (4) configured to carry out a chemical reaction (23) for electrochemically oxidizing hydrogen into water and having an air inlet (6) connected to the external space (3). When,
Water is configured to perform the electrochemically degrade the reverse chemical reaction (25) to oxygen and hydrogen, and water electrolysis with the attached oxygen outlet (7) in the internal space (2) A disassembling device (5),
A carrier line (8, 9) connecting the fuel cell (4) and the water electrolyzer (5) to each other ;
Have a, a carbon dioxide removal device (10) configured to remove carbon dioxide from the breathing air in the interior space (2) within,
A hydrogen carrier line (9) connecting the water electrolyzer (5) and the fuel cell (4);
A water carrier line (8) connecting the fuel cell (4) and the water electrolyzer (5) is included,
The carbon dioxide removing device (10),
Directing said breathing air into a solution containing sodium hydroxide,
The solution is regenerated by adding calcium hydroxide, which forms calcium carbonate,
Decomposes the calcium carbonate into calcium oxide and carbon dioxide by heating,
Releasing the carbon dioxide into the air of the external space (3),
Dissolving the calcium oxide in water,
Returning to the step of regenerating the calcium hydroxide,
The exhaust heat of the fuel cell (4) is used to decompose the calcium carbonate,
It is configured as follows,
A device that regenerates breathing air. And a configured CO ₂ sensor (14) to determine the carbon dioxide content in the gas,
The device according to claim 4 . A moisture removal device (11) configured to remove water vapor from the breathing air in the interior space (2);
The device according to claim 4 .

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