JP4515571B2 - Solvent recovery device and solvent recovery method - Google Patents

Description

表１に示すように、本実施例の場合、水蒸気量、冷却水共に著しく少なくて済み、使用電気量も活性炭吸着方式に比べて少ないという結果が得られた。
【００３８】
〔別実施の形態〕
（１） 上記実施形態のフィルター装置には、ＳｉＯ₂ 膜を使用した例を示したが、セラミックフィルターとしてはこれに限定されず、溶剤分子を水、空気、窒素などの無害成分の分子と分離可能であれば他の珪素系、その他のセラミックフィルターを用いてもよい。
【００３９】
（２） 本実施形態の溶剤回収装置は、塗装工場の他、シンナーを使用する印刷工場、樹脂フィルムを接着するラミネート工場、ＩＣ洗浄ライン、その他種々の有機溶剤を含む排ガス発生個所に対して適用でき、排気ガス中に含まれる溶剤を従来にない新規な手段により、低コストに回収可能な装置および方法を提供するものである。
【図面の簡単な説明】
【図１】本発明の一実施形態に係る溶剤回収装置の概略全体構成図
【符号の説明】
１ フィルター装置
２ 冷却装置
２ａ 配管
３ 回収手段
４ 分離膜層
６ 排気手段
１１，１２ 活性炭吸着装置[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a solvent recovery apparatus and a solvent recovery method, and more particularly to a solvent recovery apparatus that recovers an organic solvent by separating the organic solvent using a ceramic filter and a solvent recovery method using the same.
[0002]
[Prior art]
In the case where an organic solvent (hereinafter, simply referred to as “solvent” in the present specification) is contained in exhaust gas discharged from an integrated circuit cleaning line, a painting factory, etc., conventionally, an adsorption method using activated carbon, a catalyst It is processed by a combustion method, an absorption method using an absorbing solution, or the like. In the case of the catalytic combustion method, the burned gas contains harmful components and needs to be treated, whereas the adsorption method using activated carbon does not require that, and it is a low-concentration exhaust gas. However, since it can be concentrated and has high efficiency, it is used relatively frequently.
[0003]
As the activated carbon adsorption method, a method of adsorbing to activated carbon and desorbing and recovering the adsorbed solvent while heating is often performed. This system uses a rotary adsorption / desorption device having a plurality of compartments arranged in the circumferential direction side by side and having a rotating drum filled with activated carbon in each chamber in the flow direction. While slowly rotating the rotating drum, the exhaust gas is allowed to flow to adsorb the solvent to the activated carbon, and the adsorbed activated carbon portion is further rotated to allow heated air to flow to desorb the adsorbed solvent. The desorbed solvent is concentrated and recovered or detoxified.
[0004]
[Problems to be solved by the invention]
However, this method requires a large amount of equipment, is complicated and has a high equipment cost, and has a high running cost in operating the equipment such as consuming a large amount of cooling water. As another method, a method of absorbing and removing the solvent by bringing the solvent-containing gas into contact with the absorbing liquid is also used, but this method also requires a distillation device, such as a distillation apparatus, and the energy consumption is large, The running cost required is not small. In particular, in the case of low-concentration exhaust gas, the equipment configuration must be large under the control of the air volume. However, as nowadays, it is not allowed to release organic solvents into the atmosphere due to the increase in environmental awareness, and there is a strong demand for the appearance of equipment with low equipment costs and running costs.
[0005]
SUMMARY OF THE INVENTION In view of the above-described problems of the prior art, an object of the present invention is to provide a solvent recovery apparatus and a solvent recovery method capable of recovering a solvent surely with a simple apparatus configuration, low equipment cost and running cost. There is.
[0006]
[Means for Solving the Problems]
The above object can be achieved by the inventions described in the claims. That is, the characteristic configuration of the solvent recovery apparatus according to the present invention includes activated carbon adsorption means for adsorbing the solvent in the object to be processed,
Water vapor supply means for supplying water vapor to the activated carbon adsorption means and desorbing the solvent adsorbed on the activated carbon adsorption means;
A filter device comprising a separation film mainly composed of a SiO ₂ film containing ZrO ₂ , which separates the gaseous solvent and water vapor from the desorbed water vapor containing the solvent ;
A cooling device for cooling and agglomerating the gaseous solvent delivered from the filter device;
A solvent recovery device comprising a recovery means for recovering the solvent agglomerated by the cooling device,
It is provided with a bypass circuit for connecting the water vapor supply means and the filter device, and for supplying water vapor supplied from the water vapor supply means to the filter device.
[0007]
According to this configuration, the configuration of the device is simplified compared to the conventional active material adsorption device, the entire device is significantly compact and the running cost is low, and a large amount of heat source and other energy are used for solvent recovery. In addition, since a distillation apparatus that consumes a large amount of energy is not used, running costs are significantly reduced, and separation is performed by a separation membrane that can be separated by the molecular sieving effect due to the pores. By doing so, a separation membrane having excellent selectivity can be obtained. Furthermore, the heat resistance can be further improved by using a separation film mainly composed of a SiO ₂ film containing ZrO ₂ as the separation film. As described above, since the separation membrane has heat resistance, by supplying high-temperature and high-pressure steam to the activated carbon adsorption device, the desorption rate of the adsorbed solvent is increased, and the separation and recovery efficiency is increased to increase the solvent. It can be recovered.
[0008]
The desorption after the adsorption of the solvent by the activated carbon adsorption device is preferably performed by supplying high-temperature high-pressure steam to the activated carbon adsorption device.
[0009]
According to this configuration, the solvent adsorbed by the activated carbon can be forcibly fed to the downstream filter device, and the separation and recovery of the solvent can be ensured reliably by the filter device and the subsequent steps. Here, the high-temperature high-pressure steam refers to high-pressure steam heated to about 500 ° C. over 150 ° C. It is preferable to increase the steam to be fed at a high temperature and a high pressure because the desorption speed with activated carbon is increased and the recovery efficiency at the time of separation and recovery of the solvent in the filter device which is a subsequent process is increased. Since the recovery efficiency increases, the solvent concentration can be efficiently recovered with respect to an object to be processed having a high concentration of about 10,000 ppm.
[0010]
The filter device has an inlet for an object to be processed treated by the activated carbon adsorption device, a separation membrane layer for capturing a solvent in the object to be processed, and a solvent captured by the separation membrane layer to the cooling device. A solvent supply port for feeding out, and connected to an exhaust means for exhausting innocuous components other than the solvent trapped in the separation membrane, and the separation membrane layer is made of a SiO ₂ membrane having pores. preferable.
[0011]
According to this configuration, a cooling device that can efficiently discharge or collect innocuous components such as air, nitrogen, and moisture other than the solvent captured by the separation membrane layer, and capture the solvent having a large molecular diameter and recover the solvent. In addition, it is convenient not only to be able to reliably feed in, but also to be able to reliably separate harmless air, nitrogen and moisture from a solvent having a large molecular diameter (molecular sieving effect) by a porous SiO ₂ film. Further, since the solvent can be further separated according to the molecular diameter, it is convenient to select an optimum SiO ₂ film according to the type of the solvent contained in the exhaust gas.
[0012]
It is preferable that the pore diameter of the SiO ₂ film is 0.2 to 1.0 nm.
[0013]
If the pore diameter of the SiO ₂ membrane is less than 0.2 nm, it is difficult to produce stably, and the production cost becomes high. If it exceeds 1.0 nm, the separation efficiency is lowered, which is not preferable. The pore diameter of the SiO ₂ film is more preferably 0.25 to 0.5 nm.
[0014]
The SiO ₂ film preferably contains 1 to 50 mol% of ZrO ₂ .
[0015]
The SiO ₂ film itself has heat resistance. However, if ZrO ₂ is contained, the heat resistance is further improved, and the durability of the filter device is advantageously increased. When the ZrO ₂ content is less than 1 mol%, the effect of improving the heat resistance is not so much recognized. When the ZrO ₂ content exceeds 50 mol%, the heat resistance is remarkable for the content. This is not preferable because the effect of improving the property is not observed.
[0016]
It is preferable that the cooling device has a pipe for circulating the refrigerant therein, and can send out the cooled and agglomerated solvent to the recovery means.
[0017]
According to this configuration, the solvent sent out from the filter device is in the form of vapor, mist, etc., which is higher than room temperature, so that it can be reliably agglomerated by cooling, increase the collection efficiency, and further to the recovery means It is convenient because it is easy to feed the agglomerated solvent. As the refrigerant, a liquid such as water or a gas component may be used. When the temperature of the solvent is not so high, a refrigerant cooled through a separately provided cooling tank may be used.
[0018]
Furthermore, the characteristic configuration of the solvent recovery method according to the present invention uses the solvent recovery device according to any one of claims 1 to 5, and supplies the water vapor to the filter device via the bypass circuit. After raising the temperature of the apparatus, the processed material processed by the activated carbon adsorption device is fed to the filter device, and the filter device discharges harmless components other than the solvent in the processed material and captures the solvent. The trapped solvent is fed to a cooling device to be aggregated and recovered.
[0019]
According to this configuration, the configuration of the apparatus is simplified as compared with the conventional method using an active material adsorption apparatus, the entire apparatus is greatly reduced in size and the running cost is low, and a heat source and other energy are used for solvent recovery. Since a distillation apparatus that does not use a large amount of energy and consumes a large amount of energy is not used, the running cost is remarkably reduced, and a solvent recovery method capable of reliably collecting the solvent by aggregation can be provided. Further, as described above, by partially bypassing the water vapor introduced into the activated carbon adsorption device and introducing it into the inlet portion of the filter device, the solvent recovery efficiency can be further increased.
[0020]
Examples of solvents that can be recovered by the method of the present invention include methanol, ethanol, isopropanol, butanol, methyl ethyl ketone, acetone, methyl isobutyl ketone, acetic acid, ethyl acetate, methyl acetate, benzene, toluene, xylene, trichloroethylene, perchloroethylene, And trichloroethane.
[0021]
The separation membrane constituting the filter device is preferably manufactured by mixing an organic template with a SiO ₂ precursor sol and heat treating it.
[0022]
According to this configuration, it is convenient that a SiO ₂ separation membrane having a pore diameter in a predetermined range and having a narrow pore diameter distribution can be manufactured stably and reliably. The organic template in this case is made of an organic substance such as phenyl or vinyl, and an SiO ₂ separation membrane having a predetermined range of pore diameters is ensured by setting various types, blending amounts, and heat treatment temperatures. Is obtained.
[0023]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 shows a schematic overall configuration of the solvent recovery apparatus of the present embodiment. The solvent recovery apparatus A is connected to an end of an exhaust gas discharge path that is discharged from a paint booth provided in an automobile painting line, for example, and is an exhaust gas that is an object to be processed fed by an air supply fan F. After removing relatively large coarse particles in the prefilter 10 in advance, the activated carbon adsorption device 11 described later adsorbs the solvent (vapor, mist, etc.) in the exhaust gas, and then feeds high-temperature and high-pressure steam. The solvent is desorbed, and this is sent to the filter device 1 having a ceramic separation membrane described later. In this filter device 1, since the water vapor component is sucked and removed by a vacuum pump as an exhaust means, high-pressure air from which water vapor has been removed from high-pressure water vapor is introduced into the filter device 1. Only the solvent is pushed out to the cooling device 2 on the downstream side, where the solvent is cooled and condensed. The solvent cooled and condensed by the cooling device 2 is further collected and collected in a collection tank 3 which is a collection means on the downstream side.
[0024]
The activated carbon adsorption device 11 is of a small batch type, is configured in a honeycomb shape, and is composed of a pair of combinations. First, only the inlet side and outlet side valves 12 and 13 of one activated carbon adsorption device 11 are opened, and the exhaust gas that has passed through the prefilter 10 is fed into this to adsorb the solvent in the exhaust gas to the activated carbon. The exhaust gas from which the solvent has been removed by the activated carbon adsorbing device 11 may be piped so as to be released to the atmosphere as it is if it is harmless below the exhaust standard and to be introduced again into the activated carbon adsorbing device depending on the concentration.
[0025]
When the solvent is sufficiently adsorbed by the activated carbon adsorbing device 11, the inlet side and outlet side valves 12 and 13 of one activated carbon adsorbing device 11 are closed, and the main valve 14 for introducing water vapor is supplied to supply high-temperature and high-pressure water vapor from the outside. In addition, the inlet side and outlet side valves 15 and 16 are opened, and the inlet side and outlet side valves 18 and 19 of the other activated carbon adsorption device 17 are opened to similarly adsorb the solvent in the exhaust gas. The solvent in one activated carbon adsorption device 11 fed with high-temperature and high-pressure water vapor is desorbed from the activated carbon and is forcibly sent to the filter device 1 located on the downstream side described above. Incidentally, as water vapor at high temperature and high pressure, when heated for example to 180 ° C., if a 10kg / cm ^2, 200 ℃, a 16 kg / cm ² pressure of about.
[0026]
When the adsorption of the solvent in the other activated carbon adsorbing device 17 is completed, the valves 20 and 21 are opened to supply high-temperature and high-pressure water vapor to the activated carbon adsorbing device 17 from the outside, and the solvent is separated from the activated carbon. Forced to send. In addition, the combination of the activated carbon adsorption device is not limited to a pair of combinations, and may be appropriately added according to the processing amount, and the type is not limited to the honeycomb type, and is a pipe shape or a plate shape. An activated carbon adsorbing device configured as described above may be used, and further, a fiber activated carbon may be used. However, it is preferable to configure the activated carbon adsorption device 11 in a honeycomb shape since the specific surface area is large, so that the whole can be made compact and the pressure loss can be reduced.
[0027]
The filter device 1 to which the solvent is fed has an inlet for receiving the exhaust gas and an outlet for sending the solvent to the next process, and the inside is filled with a layer of SiO ₂ film, which is a separation membrane 4 capable of trapping the solvent. It has a structure. The filter device 1 is provided with a discharge pipe 5 so that the inside of the device is sucked by a vacuum pump 6, and removes harmful components such as air, nitrogen, moisture, etc. other than the organic solvent captured by the SiO ₂ film 4. Drain (molecular sieve effect). In addition, when the recovery device is started, the inlet portion of the filter device 1 is not heated, so that the high-temperature and high-pressure water vapor containing the solvent fed from the activated carbon adsorption device 11 is separated by the separation membrane of the filter device 1. There is a possibility that the temperature is reduced and agglomerates before, and the solvent recovery rate may be lowered. However, in order to prevent the temperature drop or reboiling at that time, by partially bypassing the water vapor introduced into the activated carbon adsorption device 11 The water vapor V is introduced into the inlet portion of the filter device 1. This bypass circuit is not always necessary, but adopting such a configuration is advantageous in that the solvent recovery efficiency can be further increased.
[0028]
Although the roots type vacuum pump is used as the vacuum pump 6, other types may be used, and the suction capacity may be selected according to the internal capacity of the filter device 1, and the solvent trapped by the filter device 1 is cooled. What is necessary is just to make it as long as it does not interfere with sending out to the apparatus. In addition, the figure number 22 is a water receiving tank, the figure number 23 is a drain receiving tank, and is discharged | emitted by the pump P suitably. In the water receiving tank 22 and the drain receiving tank 23, it is preferable to arrange a water level gauge 24 so that the liquid level can be controlled.
[0029]
In addition, although the example which comprised the filter apparatus 1 to the vertical type in FIG. 1 is shown, a horizontal type may be sufficient, multiple groups may be arrange | positioned not only 1 unit | set, The separation membrane 4 described in detail below may be arranged in parallel over several stages, and various modifications are possible depending on the purpose.
[0030]
The solvent is sent out to the cooling device 2 on the downstream side by the high-pressure steam introduced from the exhaust gas inlet and the high-pressure air from which the steam has been removed while passing through the SiO ₂ film 4 inside the filter device 1. Of course, in order to make it easy to send the solvent to the cooling device 2, a discharge pump having an appropriate capacity may be provided on the downstream side of the cooling device.
[0031]
The SiO ₂ film is formed on a porous ceramic support such as alumina having pores whose diameter is controlled within a certain range of 0.2 nm or more and having a substantially cylindrical shape with an inner diameter of about 3 mm. Specifically, the pore diameter of the SiO ₂ film is preferably 0.2 to 1.0 nm. When the pore diameter of the SiO ₂ film is less than 0.2 nm, the production cost is high, and when it exceeds 1.0 nm, the separation efficiency is lowered, which is not preferable. The pore diameter of the SiO ₂ film is more preferably 0.25 to 0.5 nm. A porous ceramic support that supports the SiO ₂ film is closely packed in the filter device 1 to separate the sent solvent and other components. Of course, SiO ₂ membranes having various separation capabilities can be selectively used depending on the type of exhaust gas.
[0032]
Production of the SiO ₂ film, for example, a SiO ₂ precursor sol, a mixture of organic template, such as functional group contained in the resin foam and resin fiber or SiO ₂ precursor sol was heat-treated into a predetermined temperature By volatilizing the organic component, an SiO ₂ film having a pore diameter in a predetermined range and having a narrow pore diameter distribution can be produced. The pore diameter and pore volume of the SiO ₂ film can be controlled by appropriately changing and selecting the type of organic template, heat treatment conditions, and the like. Accordingly, it is possible to form a membrane that can exhibit a significantly superior effect in selectivity compared to a gas separation membrane made of a polymer material. Moreover, the heat resistance can be further improved by containing ZrO ₂ in the range of 1 to 50 mol% in the SiO ₂ film. In this case, if the ZrO ₂ content is less than 1 mol%, the effect of improving the heat resistance is not so recognized, and if the ZrO ₂ content exceeds 50 mol%, it is remarkable for the content. This is not preferable because the effect of improving heat resistance is not observed.
[0033]
The cooling device 2 is provided with one or two or more pipes 2a through which a refrigerant (cold water or the like) flows, and the pipe 2a is connected to the cooling tank 7 so that the solvent and the pipe surface are separated. The contact causes the solvent to aggregate on the pipe surface. Since most of the water is removed by the filter device 1, the cooling capacity of the cooling device 2 may be small-scale, and therefore less cold water is used. The pipe 2a may be one in which a large number of small-diameter single pipes are arranged, or may be one in which a large number of cooling fins are formed in a single pipe, or in a spiral shape.
[0034]
The solvent agglomerated in the cooling device 2 falls downward and accumulates in the recovery tank 3, and is appropriately taken out by the pump P and recovered. The recovery tank 3 is also preferably provided with a water level gauge 24 so that the liquid level can be controlled. The exhaust gas from which the solvent has been removed by the cooling device 2 is rendered harmless and is released to the atmosphere.
[0035]
As explained above, the solvent recovery apparatus of this embodiment can make the whole apparatus compact and can reliably separate and recover the solvent, and the solvent recovery method using this apparatus uses a great deal of thermal energy. Since there is no, running costs can be kept low.
[0036]
【Example】
Compare the result of treating exhaust gas containing 1,400 ppm of isopropyl alcohol (temperature: 40 ° C. Gas flow rate: 19,000 Nm ³ / h) using the above-mentioned solvent recovery device with the result of recovery using other methods. However, it is shown in Table 1.
[0037]
[Table 1]

As shown in Table 1, in the case of the present example, both the amount of water vapor and the cooling water are remarkably small, and the amount of electricity used is smaller than that of the activated carbon adsorption method.
[0038]
[Another embodiment]
(1) Although an example using a SiO ₂ film was shown in the filter device of the above embodiment, the ceramic filter is not limited to this, and solvent molecules are separated from molecules of harmless components such as water, air, and nitrogen. If possible, other silicon-based or other ceramic filters may be used.
[0039]
(2) The solvent recovery device of the present embodiment is applied to a printing factory using a thinner, a laminating factory for bonding a resin film, an IC cleaning line, and other exhaust gas generation places including various organic solvents in addition to a coating factory. The present invention provides an apparatus and a method capable of recovering the solvent contained in the exhaust gas at a low cost by a novel means that has not been conventionally used.
[Brief description of the drawings]
FIG. 1 is a schematic overall configuration diagram of a solvent recovery apparatus according to an embodiment of the present invention.
DESCRIPTION OF SYMBOLS 1 Filter apparatus 2 Cooling apparatus 2a Piping 3 Collecting means 4 Separation membrane layer 6 Exhaust means 11, 12 Activated carbon adsorption apparatus

Claims (7)

Activated carbon adsorption means for adsorbing the solvent in the workpiece,
Water vapor supply means for supplying water vapor to the activated carbon adsorption means and desorbing the solvent adsorbed on the activated carbon adsorption means;
A filter device comprising a separation film mainly composed of a SiO ₂ film containing ZrO ₂ , which separates the gaseous solvent and water vapor from the desorbed water vapor containing the solvent ;
A cooling device for cooling and agglomerating the gaseous solvent delivered from the filter device;
A solvent recovery device comprising a recovery means for recovering the solvent agglomerated by the cooling device,
A solvent recovery apparatus comprising a bypass circuit for connecting the water vapor supply means and the filter device, and for supplying water vapor supplied from the water vapor supply means to the filter device. The solvent recovery apparatus according to claim 1, wherein the desorption after the adsorption of the solvent by the activated carbon adsorption apparatus is performed by feeding high temperature and high pressure steam to the activated carbon adsorption apparatus. The filter device has an inlet for an object to be processed treated by the activated carbon adsorption device, a separation membrane layer for capturing a solvent in the object to be processed, and a solvent captured by the separation membrane layer to the cooling device. The solvent recovery apparatus according to claim 1 or 2, further comprising a solvent supply port for sending out and connected to an exhaust means for exhausting innocuous components other than the solvent trapped by the separation membrane. Solvent recovery apparatus according to claim 3 pore diameter of the SiO ₂ film is 0.2～1.0Nm. The solvent recovery apparatus according to claim 3 or 4, wherein the SiO ₂ film contains 1 to 50 mol% of ZrO ₂ . The solvent recovery device according to any one of claims 1 to 5, wherein the water vapor is supplied to the filter device via the bypass circuit to raise the temperature of the filter device, and then the activated carbon adsorption is performed on the filter device. The processed material processed by the device is fed, and the filter device discharges harmless components other than the solvent in the processed material, captures the solvent, and feeds the captured solvent to the cooling device for aggregation and recovery. Solvent recovery method. The solvent recovery method according to claim 6, wherein the separation membrane constituting the filter device is manufactured by mixing an organic template with a SiO ₂ precursor sol and heat-treating the organic template.

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