Removal device and removal system for siloxane gas, residential facility equipped with removal device, and method for removing siloxane gas

Abstract

This removal device for a siloxane gas comprises a flow passage for air containing the siloxane gas, a gas-heating part for heating the siloxane gas, and an adsorption filter for adsorbing the siloxane gas heated in the gas-heating part.

Description

Siloxane gas removal device, removal system, residential facility equipped with removal device, and method for removing siloxane gas

[0001] The present invention relates to an apparatus for removing siloxane gases, a removal system, a residential facility equipped with the removal apparatus, and a method for removing siloxane gases.

[0002] In enclosed spaces such as living quarters and shelters on space stations where ventilation with outside air is difficult, it is necessary to suppress atmospheric contamination of the living space in order to maintain the lives of the occupants, and it is necessary to remove harmful gases from the air.

[0003] Figure 1 in Non-Patent Document 1 discloses a harmful gas removal system using phosphoric acid-impregnated activated carbon and an oxidation catalyst. In this removal system, air containing harmful gases emitted from living spaces is first passed through phosphoric acid-impregnated activated carbon, which primarily removes ammonia. The air that has passed through the activated carbon is then heated, and the heated air passes through an oxidation catalyst, which primarily removes carbon monoxide.

[0004] JL Perry, 2 others, "AN ASSESSMENT OF THE INTERNATIONALSPACE STATION'S TRACE CONTAMINANT CONTROL SUBASSEMBLY PROCESS ECONOMICS", August 2005, NASA

[0005] Trace amounts of siloxane gases may be generated from various devices installed in living spaces. Siloxane gases are gases containing siloxanes, such as linear siloxanes and cyclic siloxanes having siloxane bonds. Like carbon monoxide gas, siloxane gases are harmful gases, and therefore it is desirable to remove them from living spaces. Because siloxanes are adsorbed by activated carbon, even the removal system described in Non-Patent Document 1 can remove siloxane gases along with harmful gases in the air discharged from living spaces.

[0006] However, siloxanes adsorbed on activated carbon may desorb from the activated carbon, and the desorbed siloxanes reach the oxidation catalyst together with the air flowing through the piping. In the removal system described in Non-Patent Document 1, the air flowing through the piping is heated to a high temperature before reaching the oxidation catalyst, so the siloxane gas desorbed from the activated carbon is also heated. If the siloxane gas becomes so hot that it crystallizes, siloxane particles will accumulate on the oxidation catalyst, shortening the life of the oxidation catalyst and reducing the oxidation catalyst's ability to remove carbon monoxide.

[0007] To avoid these problems, it is necessary to improve the ability to remove siloxane gases, but Non-Patent Document 1 does not mention the removal of siloxane gases.

[0008] The present invention has been made in view of the above points, and has as its object to improve the capacity for removing siloxane gases.

[0009] To achieve the above object, the present invention provides a device for removing siloxane-based gases, which is characterized by comprising a flow path for air containing the siloxane-based gases, a gas heating unit that heats the siloxane-based gases, and an adsorption filter that adsorbs the siloxane-based gases heated by the gas heating unit.

[0010] According to the present invention, the siloxane gas is heated to partially solidify (oxidize) the siloxane gas, causing siloxane particles to precipitate, and the siloxane particles can be collected by an adsorption filter. This allows the adsorption filter to both physically adsorb the siloxane particles and chemically adsorb the unsolidified siloxane gas, improving the removal capacity of the siloxane gas.

[0011] Another aspect of the present invention is a system for removing siloxane-based gases, comprising a removal device that adsorbs the siloxane-based gases, and an oxidation catalyst that is arranged downstream of the removal device in a flow path of air containing the siloxane-based gases, and the gas heating unit is a heat exchanger that exchanges heat between the upstream side of the adsorption filter and the downstream side of the oxidation catalyst.

[0012] Another aspect of the present invention is a residential facility with a manned enclosed space, comprising: a removal device that adsorbs the siloxane gas; and an oxidation catalyst that is arranged downstream of the removal device in a flow path of air containing the siloxane gas, and the gas heating section is a heat exchanger that exchanges heat between the upstream side of the adsorption filter and the downstream side of the oxidation catalyst.

[0013] According to yet another aspect, the present invention is a method for removing siloxane gases, characterized in that the siloxane gases are heated and the heated siloxane gases are adsorbed onto an adsorption filter, thereby removing the siloxane gases.

[0014] According to the present invention, the removal capacity of siloxane gases can be improved.

[0015] FIG. 1 is an explanatory diagram showing an outline of the system of a removal system equipped with a removal device according to an embodiment. FIG. 2 is an explanatory diagram showing another example of the configuration of a removal device. FIG. 3 is an explanatory diagram showing another example of the configuration of a removal device. FIG. 4 is an explanatory diagram showing another example of the configuration of a removal device. FIG. 5 is an explanatory diagram showing another example of the configuration of a removal device. FIG. 6 is an explanatory diagram for explaining switching of flow paths. FIG. 7 is an explanatory diagram showing an outline of the configuration of a residential facility equipped with a removal device.

[0016] Hereinafter, embodiments of the present invention will be described with reference to the drawings. In this specification and the drawings, elements having substantially the same functional configurations are designated by the same reference numerals, and redundant description will be omitted.

[0017] 1 is an explanatory diagram showing an outline of a system for removing siloxane gases 1 equipped with a removal device 10 according to this embodiment. The removal system 1 according to this embodiment takes in air from a living space such as a cabin, removes ammonia, carbon monoxide, siloxane gases, etc. contained in the air, and supplies the treated air back to the living space. The removal system 1 is preferably installed in manned enclosed spaces where ventilation is difficult, such as living spaces or work spaces on space stations, clean rooms, shelters, submarines, and hospitals, or in living facilities equipped with such spaces.

[0018] 1, the removal system 1 has a flow path 2 for air containing siloxane gases, which is formed, for example, by piping. The flow path 2 is provided with, in order from the upstream side, an activated carbon filter 3, a blower 4, a removal device 10, an oxidation catalyst device 20, and a neutralization filter 5.

[0019] The activated carbon filter 3 adsorbs ammonia and siloxanes contained in the air discharged from the living space. Note that even if siloxanes are once adsorbed by the activated carbon filter 3, they may later desorb and flow out downstream of the activated carbon filter 3. Furthermore, for example, when the concentration of siloxane gas is high, the siloxanes may not be sufficiently adsorbed by the activated carbon filter 3 and may flow out downstream of the activated carbon filter 3.

[0020] The blower 4 sends the air that has passed through the activated carbon filter 3 toward the removal device 10. The flow rate of the air sent out from the blower 4 is, for example, 10 to 20 m 3 / h. In this embodiment, the entire amount of air discharged from the living space is sent toward the removal device 10, but it is also possible to provide a bypass flow path (not shown) branching off from the flow path 2, as in the removal system described in Non-Patent Document 1, and return part of the air to the living space through the bypass flow path without removal processing. In this case, the flow rate of air toward the removal device 10 is, for example, 4 to 6 m 3 / h, and the flow rate of air flowing through a bypass flow path (not shown) is, for example, 6 to 14 m 3 / h.

[0021] The removal device 10 includes a heater 11 as a gas heating unit for heating the siloxane gas, and an adsorption filter 12 for adsorbing the siloxanes.

[0022] The heater 11 is disposed upstream of the adsorption filter 12 in the flow path 2 and directly heats the air containing siloxane gas flowing through the flow path 2. When the siloxane gas is heated by the heater 11, a portion of the siloxane gas solidifies, causing siloxane particles to precipitate. These precipitated siloxane particles reach the adsorption filter 12 along with the unsolidified siloxane gas. Then, in the adsorption filter 12, physical adsorption of the siloxane particles and chemical adsorption of the unsolidified siloxane gas occur, thereby removing the siloxane gas. The heating method of the sludge heating unit is not particularly limited as long as it is possible to heat the siloxane gas flowing through the flow path 2.

[0023] The siloxane gas is preferably heated to 200° C. to 400° C. When the temperature of the siloxane gas is 200° C. or higher, the amount of siloxane particles precipitated increases, and the amount of siloxanes physically adsorbed by the adsorption filter 12 increases. This further improves the removal processing capability of the siloxane gas by the removal device 10.

[0024] Furthermore, in the oxidation catalyst device 20 described below, the air flowing through the flow path 2 is heated to, for example, 400°C, but if the siloxane gas is heated to 200°C to 400°C by the heater 11, the air can be sufficiently preheated upstream of the oxidation catalyst device 20. In this case, heating of the air in the oxidation catalyst device 20 can be omitted or the amount of heating can be significantly reduced.

[0025] The material of the adsorption filter 12 may be any material capable of adsorbing siloxane gases, such as porous materials such as activated carbon, silica gel, activated alumina, and zeolite. Of these porous materials, zeolite is preferred. The adsorption filter 12 is preferably detachable to facilitate replacement.

[0026] Next, a description will be given of the oxidation catalyst device 20. In this oxidation catalyst device 20, reducing gases such as carbon monoxide contained in the air that has passed through the adsorption filter 12 are oxidized.

[0027] The oxidation catalyst device 20 includes a catalyst heater 21 that heats the air flowing through the flow path 2, an oxidation catalyst 22 through which the heated air passes, and a heat exchanger 23 installed downstream of the oxidation catalyst 22.

[0028] The set temperature of the catalytic heater 21 is set to, for example, 400°C, and the air flowing through the flow path 2 is heated by the catalytic heater 21 to approximately 400°C upstream of the oxidation catalyst 22. Harmful reducing gases such as carbon monoxide contained in the heated air are oxidized and rendered harmless as they pass through the oxidation catalyst 22. The temperature of the air passing through the oxidation catalyst 22 rises due to the reaction heat generated by this oxidation reaction, but heat is transferred from the high-temperature air to the flow path 2 upstream of the catalytic heater 21 via a heat exchanger 23 installed downstream of the oxidation catalyst 22, and the air is preheated upstream of the catalytic heater 21.

[0029] The neutralization filter 5 neutralizes harmful gases that may be produced by the oxidation reaction of the oxidation catalyst 22. For example, if the air reaching the oxidation catalyst 22 contains a gas containing chlorine, hydrogen chloride may be produced by the oxidation reaction. The neutralization filter 5 is made of an alkaline material such as lithium hydroxide, and the hydrogen chloride is neutralized and made harmless by passing through the neutralization filter 5. The air that has passed through the neutralization filter 5 is then returned to the living space.

[0030] The above has described the general configuration of the removal system 1 including the removal device 10 according to this embodiment. Note that components such as a flow meter and a valve (not shown) are also installed on the flow path 2 as appropriate.

[0031] In the removal device 10 according to this embodiment, the siloxane gas is heated to solidify a portion of the siloxane gas, causing siloxane particles to precipitate, and the siloxane particles can be collected by the adsorption filter 12. Therefore, according to the removal device 10 according to this embodiment, both physical adsorption of the siloxane particles and chemical adsorption of the unsolidified siloxane gas occur in the adsorption filter 12, and therefore the removal capability of the siloxane gas can be improved compared to conventional removal systems.

[0032] Furthermore, pores may form on the surfaces of siloxane particles physically adsorbed to the adsorption filter 12, and other particles may physically adsorb onto the surfaces of particles with pores formed thereon. In other words, the physically adsorbed siloxane particles themselves exhibit new physical adsorption capabilities, so that even if the amount of siloxane gas particles deposited on the adsorption filter 12 increases, the physical adsorption force is prevented from decreasing. This allows the adsorption filter 12 to maintain its ability to remove siloxane gases through physical and chemical adsorption for a long period of time.

[0033] Furthermore, according to the removal system 1 equipped with the above-described removal device 10, the removal device 10 can heat the air in the flow path 2, making it possible to suppress the amount of heating of the air in the oxidation catalyst device 20 installed downstream of the removal device 10. In other words, even when the removal device 10 is newly incorporated into an existing removal system, the total amount of energy consumed by the entire removal system can be made roughly equal to that of an existing removal system that does not have the removal device 10. For this reason, it is particularly useful to apply the removal device 10 to removal systems used in environments where available energy is limited, such as space stations and shelters.

[0034] In addition, in the removal system 1, the removal process of siloxane gases is performed upstream of the oxidation catalyst 22, which prevents crystallization of siloxane gases in the oxidation catalyst 22, which occurs in conventional removal systems. This makes it possible to extend the life of the oxidation catalyst 22 and the continuous operating time of the removal system 1.

[0035] Next, other configuration examples of the removal device 10 or the removal system 1 will be described.

[0036] The example shown in Figure 2 is an example in which, in addition to the heater 11 serving as a gas heating section, a filter heater 13 serving as a filter heating section for heating the adsorption filter 12 is installed. By providing the filter heater 13 in the removal device 10 as shown in Figure 2, it is possible to heat the siloxane gas passing through the adsorption filter 12. This can promote the solidification of siloxane gas that was not solidified by heating with the heater 11, and can increase the amount of siloxane particles physically adsorbed on the adsorption filter 12.

[0037] Furthermore, by heating the adsorption filter 12, the chemically adsorbed siloxane gas molecules can be solidified and precipitated as siloxane particles. By precipitating the chemically adsorbed siloxane gas molecules as siloxane particles in this way, the chemical adsorption power of the adsorption filter 12 is restored, and a high chemical adsorption power for subsequent siloxane gases can be maintained. The heating method of the filter heating unit is not particularly limited as long as it can heat the adsorption filter 12.

[0038] 3 is an example in which the heater 11 serving as the gas heating section of the removal device 10 is installed so as to also function as the filter heating section. In this example, the heater 11 heats the adsorption filter 12 and the siloxane gas passing through the adsorption filter 12. Therefore, even with the configuration of the removal device 10 shown in FIG. 3, it is possible to solidify a portion of the siloxane gas, and to cause both physical adsorption of siloxane particles and chemical adsorption of unsolidified siloxane gas in the adsorption filter 12.

[0039] The example shown in Figure 4 is an example in which the removal device 10 is incorporated into an oxidation catalyst device 20. In this example, the gas heating section that heats the siloxane gas is a catalytic heater 21, and the removal device 10 is composed of the catalytic heater 21 and an adsorption filter 12. In this removal device 10, air containing siloxane gas flowing through the flow path 2 reaches the adsorption filter 12 after being heated by the catalytic heater 21. Therefore, even with the configuration of the removal device 10 shown in Figure 4, it is possible for the adsorption filter 12 to both physically adsorb siloxane particles and chemically adsorb unsolidified siloxane gas.

[0040] The example shown in Figure 5 is an example in which a heat exchanger 14 is installed as a gas heating section of the removal device 10. In this example, the heat exchanger 14 is disposed at a position where heat exchange is possible between the flow path 2 between the blower 4 and the adsorption filter 12 and the flow path 2 between the oxidation catalyst 22 and the neutralization filter 5. According to the removal system 1 shown in Figure 5, the reaction heat generated in the oxidation catalyst 22 can be used to heat the siloxanes gas before it passes through the adsorption filter 12, allowing siloxane particles to precipitate. This allows the adsorption filter 12 to cause both physical adsorption of siloxanes particles and chemical adsorption of unsolidified siloxanes gas.

[0041] 6 shows an example in which the flow path 2 branches into a first flow path 2a and a second flow path 2b in the removal device 10. As shown in Fig. 6, the first flow path 2a is provided with a first heater 11a as a first gas heating unit and a first adsorption filter 12a. Similarly, the second flow path 2b is provided with a second heater 11b as a second gas heating unit and a second adsorption filter 12b.

[0042] 6 further includes valves V1 to V4 as a flow path switching mechanism, with valves V1 and V2 provided in the first flow path 2a and valves V3 and V4 provided in the second flow path 2b. Valve V1 is located upstream of the first heater 11a, valve V2 is located downstream of the first adsorption filter 12a, valve V3 is located upstream of the second heater 11b, and valve V4 is located downstream of the second adsorption filter 12b. Furthermore, the first flow path 2a and the second flow path 2b branch off from the flow path 2 upstream of valves V1 and V3, and merge downstream of valves V2 and V4.

[0043] The valves V1 to V4 are automatically opened and closed under the control of a control unit 30. The control unit 30 is, for example, a computer equipped with a CPU, memory, etc., and has a program storage unit (not shown). The program storage unit stores various programs for executing control to switch the flow path of air containing siloxane gas, which will be described later.

[0044] 7 is a diagram for explaining the switching of the flow paths. Of the valves V1 to V4 in FIG. 7, the valves shown in black indicate a closed state, and the valves shown in white indicate an open state.

[0045] 7(a), when valves V1 and V2 are open and valves V3 and V4 are closed, air containing siloxane gas flows through the first flow path 2a. The siloxane gas flowing through the first flow path 2a is heated by the first heater 11a and then removed by being adsorbed by the first adsorption filter 12a.

[0046] 7(b), when the valves V1 and V2 are closed and the valves V3 and V4 are open, the air containing the siloxanes gas that had been flowing through the first flow path 2a flows into the second flow path 2b. That is, the flow path for the air containing the siloxanes gas switches from the first flow path 2a to the second flow path 2b. The siloxanes gas flowing through the second flow path 2b is heated by the second heater 11b and then removed by being adsorbed by the second adsorption filter 12b.

[0047] At this time, air remains stagnant in the first flow path 2a, but the first heater 11a is in an activated state. Therefore, heating of the first flow path 2a continues. This promotes solidification of the siloxane gas molecules chemically adsorbed by the first adsorption filter 12a, and the siloxane particles are precipitated, thereby recovering the chemical adsorption power of the first adsorption filter 12a.

[0048] Thereafter, when the flow path for the air containing siloxanes gases is switched back to the first flow path 2a, the second heater 11b remains in operation and continues to heat the second flow path 2b, thereby maintaining the second adsorption filter 12b at a high temperature (e.g., 200 to 400°C), and the chemically adsorbed siloxanes gas molecules solidify, thereby recovering the chemical adsorption power of the second adsorption filter 12b.

[0049] 6 and 7, the removal device 10 can alternately switch the flow path of the siloxane gas between the first flow path 2a and the second flow path 2b. This allows the chemical adsorption power of the adsorption filter installed in one flow path to be fully restored while air containing siloxane gas flows through the other flow path. This means that the life of the adsorption performance of the adsorption filters 12a and 12b installed in each flow path can be extended, and the continuous operating time of the removal device 10 can be increased.

[0050] The switching of the flow paths is achieved by controlling the opening and closing of valves V1 to V4 based on a preset time. For example, when air containing siloxane gas is flowing through the first flow path 2a, when a time preset in the control unit 30 has elapsed since air began flowing through the first flow path 2a, the control unit 30 outputs a control signal to close valves V1 and V2 and open valves V3 and V4. This switches the open / closed state of each of valves V1 to V4, and the air flow path is switched from the first flow path 2a to the second flow path 2b.

[0051] Thereafter, when a preset time has elapsed since air containing siloxane gas began to flow through the second flow path 2b, control signals for opening valves V1 and V2 and closing valves V3 and V4 are output from the control unit 30. This switches the open / closed state of each of the valves V1 to V4, and the air flow path switches from the second flow path 2b to the first flow path 2a.

[0052] The above-mentioned "preset time" in the opening and closing control of valves V1 to V4 is set based on testing or experience, taking into consideration the time required for the adsorption performance of an adsorption filter installed in a flow path through which air flows to reach its limit, and the time required for the chemical adsorption power of an adsorption filter installed in a flow path through which air does not flow to recover.

[0053] Furthermore, the valves V1 to V4 may be opened and closed manually rather than automatically by the control unit 30. In addition, the timing of switching the flow paths is not limited to a timing triggered by the lapse of a preset time, but may be a timing determined based on information detected by various sensors such as a temperature sensor (not shown).

[0054] 6 and 7, the flow path switching mechanism is configured using valves V1 to V4, but other configurations, such as a configuration using a three-way valve, may be adopted. Furthermore, the gas heating units in the first flow path 2a and the second flow path 2b may be configured to simultaneously heat the adsorption filter shown in FIG. 3, for example, or may be configured to utilize the heat generated by the oxidation catalyst 22 using the heat exchanger shown in FIGS. 4 and 5. Furthermore, in addition to the first flow path 2a and the second flow path 2b, the flow paths branching from the flow path 2 may be multiple flow paths, such as a third flow path and a fourth flow path.

[0055] 8, the removal system 1 equipped with the removal device 10 may be installed outside the living space (manned enclosed space) 41, or may be installed inside the living space 41. In other words, regardless of the installation location of the removal device 10, as long as the removal device 10 is provided as part of the living facility 40, the removal processing capacity for siloxane gases in the living space 41 can be improved.

[0056] While the present invention has been described above by way of example, it is understood that the present invention is not limited to such examples. It is clear that a person skilled in the art can conceive of various modifications and alterations within the scope of the technical ideas set forth in the claims, and that such modifications and alterations are also within the technical scope of the present invention.

[0057] For example, the components of the above-described embodiments can be combined in any manner, and such combinations will naturally provide the functions and advantages of the individual components involved in the combination, as well as other functions and advantages that will be apparent to those skilled in the art from the description herein.

[0058] Furthermore, the effects described herein are merely descriptive or exemplary and are not limiting. In other words, the technology according to the present disclosure may achieve other effects that are apparent to those skilled in the art from the description of this specification, in addition to or in place of the above-described effects.

[0059] The present invention can be applied to an apparatus for removing siloxane gases in a closed space.

[0060] REFERENCE SIGNS LIST 1 Removal system 2 Flow path 2a First flow path 2b Second flow path 3 Activated carbon filter 4 Blower 5 Neutralization filter 10 Removal device 11 Heater 11a First heater 11b Second heater 12 Adsorption filter 12a First adsorption filter 12b Second adsorption filter 13 Filter heater 14 Heat exchanger 20 Oxidation catalyst device 21 Catalyst heater 22 Oxidation catalyst 23 Heat exchanger 30 Control unit V1 to V4 Valves 40 Living facilities 41 Living space (manned enclosed space)

Claims

1. A removal device for siloxane gases, comprising: a flow path for air containing the siloxane gas; a gas heating unit that heats the siloxane gas; and an adsorption filter that adsorbs the siloxane gas heated by the gas heating unit.

2. The removal device according to claim 1, wherein the gas heating section is disposed upstream of the adsorption filter in the flow path.

3. The removal device according to claim 2, further comprising a filter heating unit for heating the adsorption filter.

4. A removal device according to any one of claims 1 to 3, characterized in that the flow path has a first flow path and a second flow path, and is equipped with a flow path switching mechanism that switches between a state in which the siloxane-based gas flows through the first flow path and a state in which the siloxane-based gas flows through the second flow path, and the gas heating unit and the adsorption filter are provided in the first flow path and the second flow path, respectively.

5. A removal device according to any one of claims 1 to 4, characterized in that the adsorption filter is detachably provided.

6. A removal device according to any one of claims 1 to 5, characterized in that the material of the adsorption filter is zeolite.

7. A removal system for siloxane gases, comprising: a removal device according to any one of claims 1 to 6 that adsorbs the siloxane gases; and an oxidation catalyst arranged downstream of the removal device in a flow path of air containing the siloxane gases, wherein the gas heating unit is a heat exchanger that exchanges heat between the upstream side of the adsorption filter and the downstream side of the oxidation catalyst.

8. A residential facility with a manned enclosed space, comprising: a removal device according to any one of claims 1 to 6 that adsorbs the siloxane gas; and an oxidation catalyst that is arranged downstream of the removal device in a flow path of air containing the siloxane gas, wherein the gas heating section is a heat exchanger that exchanges heat between the upstream side of the adsorption filter and the downstream side of the oxidation catalyst.

9. A method for removing siloxane gases, comprising heating the siloxane gases and adsorbing the heated siloxane gas onto an adsorption filter, thereby removing the siloxane gases.

10. The removal method according to claim 9, wherein the siloxane gas is heated upstream of the adsorption filter in the flow path of the air containing the siloxane gas.

11. The method of claim 10, wherein the adsorption filter is heated.

12. A removal method according to any one of claims 9 to 11, characterized in that a first flow path and a second flow path are provided as flow paths for air containing the siloxane gas, and a state in which the siloxane gas flows through the first flow path and a state in which the siloxane gas flows through the second flow path are switched.

13. A removal method according to any one of claims 9 to 12, characterized in that the temperature of the heated siloxane gas is 200 to 400°C.

14. A removal method according to any one of claims 9 to 13, characterized in that the adsorption filter is detachably provided.

15. A removal method according to any one of claims 9 to 14, characterized in that the siloxane gas is heated using reaction heat generated in an oxidation catalyst located downstream of the adsorption filter in the flow path of air containing the siloxane gas.

16. A removal method according to any one of claims 9 to 15, characterized in that the material of the adsorption filter is zeolite.

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