JP2004148211A - Method and apparatus for cleaning gas containing contaminant - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for cleaning a gas containing contaminants continuously and efficiently without using steam in a method using an active carbon fiber sheet to clean the gas. <P>SOLUTION: In the method, an adsorption apparatus system in which at least two unit adsorption apparatuses comprising closable containers are combined is used. In the container, the active carbon fiber sheet which has two electrodes and generates heat by energization is arranged. The method includes an adsorption process in which in at least one unit adsorption apparatus, the contaminant in the gas are adsorbed by the sheet and a desorption process in which in at least one unit adsorption apparatus, the adsorbed contaminants are desorbed. In the adsorption process, the gas containing the contaminants is supplied to the unit adsorption apparatus, and in the desorption process, an electric current is passed between the electrodes while the unit adsorption apparatus is evacuated to make the sheet generate heat. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method and an apparatus for cleaning a gas containing contaminants.
[0002]
[Prior art]
In order to clean a gas containing a contaminant such as an organic solvent, a contaminant-containing gas is introduced into a container in which an activated carbon fiber sheet is disposed, and the contaminant is adsorbed on the sheet. There is known a method of introducing steam into a container to desorb (desorb) contaminants adsorbed on the sheet.
However, such a method using steam generally requires a large-scale apparatus and requires steam management, and since the heating of the sheet by steam is performed by heat transfer, the heating efficiency is not so high. In consideration of the loss, the heating efficiency is considerably low and the running cost is high at present. In addition, in order to collect contaminants such as a solvent, the solvent must be separated from water, so that strict water control for preventing pollution was required.
[0003]
[Problems to be solved by the invention]
The present invention relates to a method and an apparatus using an activated carbon fiber sheet for cleaning a gas containing contaminants, wherein the method for continuously and efficiently cleaning the gas without using steam is provided. It is an object to provide an apparatus.
[0004]
[Means for Solving the Problems]
The present inventors have conducted intensive studies to solve the above problems, and as a result, completed the present invention.
That is, according to the present invention, a method and an apparatus for purifying a gas containing a contaminant described below are provided.
(1) In order to clean a gas containing contaminants, at least two unit adsorption devices including a closed container having two electrodes and having an activated carbon fiber sheet that generates heat when energized disposed therein are used. A method using a combined adsorber system, wherein the at least one unit adsorber adsorbs contaminants in the gas onto the activated carbon fiber sheet; and the at least one unit adsorber comprises activated carbon. The method includes a desorption step of desorbing the contaminants adsorbed on the fiber sheet, and the adsorption step is performed by supplying the contaminant-containing gas to the unit adsorption device. A method of purifying a gas containing contaminants, wherein electricity is supplied between the electrodes while the air is exhausted to generate heat in the activated carbon fiber sheet.
(2) The method according to (1), wherein the activated carbon fiber sheet is a roll-shaped wound body.
(3) An apparatus for purifying a gas containing contaminants,
(I) having a plurality of unit adsorption devices each having a closed container having two electrodes and having therein an activated carbon fiber sheet that generates heat when energized;
(Ii) a gas supply pipe having an open / close valve is provided in the airtight container;
(Iii) a gas exhaust pipe connected to an exhaust system via a closed valve is connected to the airtight container;
(Iv) a lead wire for energization is connected to the electrode of the activated carbon fiber sheet;
(V) the lead wire is connected to a power supply circuit via a switch circuit;
(Vi) having a control device for operating the open / close valve;
(Vii) having a control device for operating the switch circuit;
An apparatus for purifying gas containing contaminants.
(4) The apparatus according to the above (3), wherein the activated carbon fiber sheet is a rolled wound body.
[0005]
BEST MODE FOR CARRYING OUT THE INVENTION
The activated carbon fiber sheet (ACF sheet) used in the present invention is conventionally known, and includes such as woven fabric, nonwoven fabric, knitted fabric, felt and the like. In the present invention, a commercially available activated carbon fiber felt (ACF felt) can be used as it is. The ACF sheet can be used not only as a single ACF sheet but also as a laminate of a plurality (2 to 100 layers) of ACF sheets. The thickness of one ACF sheet is 0.5 to 20 mm, preferably 1 to 5.0 mm. The ACF sheet is preferably used not only as a roll-shaped wound body but also as a flat sheet-shaped laminated body.
The specific resistance of the ACF sheet is usually about 10 ^-1 to 10 ^-2? M.
[0006]
FIG. 1 shows an explanatory view of one embodiment of an ACF sheet (felt).
FIG. 2 is an explanatory view of another embodiment of the ACF sheet.
In these embodiments, electrodes 12 and 13 are respectively attached to two opposite side ends of the ACF sheet. In this case, it is important to attach the electrodes 12 and 13 to the ACF sheet so that the contact resistance (electrode resistance) is as low as possible. For this purpose, for example, as shown in FIG. 1, the electrode 12 is preferably composed of two plate-like electrodes a and b, and the electrode 13 is preferably composed of two plate-like electrodes e and f.
[0007]
The ratio R (E) of the resistance of the electrode portion (the sum of the resistance of the portion of the electrode 12 and the resistance of the portion of the electrode 13) to the resistance R (F) of the ACF sheet having the length D located between the electrodes 12 and 13 (F) / R (E) is preferably adjusted to a range of 1 or more, preferably 2 or more, more preferably 4 or more. The upper limit is not particularly limited, but is usually about 20.
The adjustment of R (F) / R (E) can be performed by reducing the R (E) by maintaining the contact between the electrodes 12 and 13 and the ACF sheet 10 at a high level. This can be done by increasing the length D of the intervening sheet to increase R (F). Further, by making R (E) small and R (F) large, it is possible to carry out efficiently.
[0008]
When R (F) / R (E) is smaller than the above range, when electricity is supplied between the electrodes 12 and 13 to generate heat in the ACF sheet 10, heat generation in those electrode portions increases, and between the electrodes. The heat generation in the located ACF sheet is reduced, so that the heat generation of the ACF sheet cannot be performed efficiently, and in addition, a disadvantage such as a short path occurs in the ACF sheet.
[0009]
In order to cause the ACF sheet 10 to generate heat in the state shown in FIG. 1, the lead wires 16 and 17 are connected to a power supply circuit, a voltage is applied between the electrodes 12 and 13, and a current is applied between both electrodes. As a result, the ACF sheet 10 generates heat.
When electricity is supplied to the ACF sheet as described above, the sheet generates heat in the sheet portion having the length d between the electrodes 12 and 13 and the sheet portion having the length D between the electrodes. In this case, the heat generated in the electrode portion is generated by the total resistance R (E) of the resistance of one electrode 12 and the resistance of the other electrode 13. Therefore, the ratio of the heat generated between the electrodes to the heat generated at the electrode portion is R (F) / R (E).
[0010]
In the state shown in FIG. 1, when a voltage is applied to one of the ACF sheets 10 (thickness: 1.6 mm) with d = 50 mm and D = 200 mm via the lead wires 16 and 17, the load on each of the electrodes 12 and 13 is increased. Under the condition of 10 gf / cm ^2, the calorific value generated by the electrodes 12 and 13 is about 15% of the total calorific value, and most generates heat according to the resistance of the length (D) ACF sheet.
In the method for generating heat of the ACF sheet, the current is increased so that the heat generation temperature (surface temperature) of the ACF sheet is set to 150 ° C. at a room temperature of 22 ° C., and when a part of the surface of the sheet becomes 150 ° C. When the distribution of the surface temperature of the ACF sheet was observed, the difference between the highest temperature (150 ° C.) and the lowest temperature (105 ° C.) was 45 ° C.
Further, it is considered that the non-uniformity of the surface temperature distribution is caused by the non-uniformity of the density of the ACF sheet. As shown in FIG. 2, five ACF sheets are stacked and heat is generated in the same manner as described above. At that time, the difference between the highest temperature and the lowest temperature was 23 ° C.
From the above, it can be seen that in order to uniformly generate heat from the ACF sheet, it is effective to cause the ACF sheet to generate heat in the form of a rolled roll or a laminate.
[0011]
Next, the heat generation method of the wound body obtained by winding the ACF sheet into a roll will be described in detail.
In the case of the roll-shaped roll of the ACF sheet, when winding the felt in a roll shape, a tape-shaped electrode is wound on or attached to both ends of the felt facing each other.
[0012]
FIG. 3A is an explanatory diagram for forming a roll-shaped wound ACF sheet by winding a tape-shaped electrode around both end portions of a long sheet-shaped ACF sheet. In this figure, 10 indicates an ACF sheet, 12 and 13 indicate tape-shaped electrodes, and 14 indicates a roll-shaped wound body of the ACF sheet. h indicates a through hole formed at the center of the wound body.
As shown in FIG. 3 (a), when the ACF sheet is roll-wound without being fixed to the ACF sheet, the tape-shaped electrode can be wound around both end portions of the ACF sheet. Can be fixed.
FIG. 3B is an explanatory view of the roll-shaped wound body of the ACF sheet formed as described above.
In this figure, 14 indicates a roll-shaped wound body, 16 and 17 indicate lead wires, and 18 and 19 indicate fastening rings.
One end of the lead wire (strip-shaped electric wire) 16 is connected to the tape-shaped electrode 12 attached to one side end of the ACF sheet 10. On the other hand, one end of the lead wire 17 is connected to a tape-shaped electrode 13 attached to the other end of the ACF sheet 10.
The fastening ring 18 is for fastening a portion of the tape-shaped electrode 12 of the roll-shaped wound body 14. The fastening ring 19 is for fastening the portion of the tape-shaped electrode 13 of the roll wound body. With this tightening ring, a pressing load is applied to each of the electrodes 12 and 13, and the contact resistance between the electrodes 12 and 13 and the felt 10 is reduced.
[0013]
In the present invention, the ACF sheet is placed in a closed container and used as a unit adsorption device.
FIG. 4 is an explanatory diagram of the unit adsorption device used in the present invention.
In FIG. 4, reference numeral 14 denotes a roll-shaped wound body of an ACF sheet, reference numerals 12 and 13 denote electrodes, reference numerals 16 and 17 denote lead wires, reference numeral 21 denotes a closed container, reference numeral 22 denotes a gas supply line, reference numeral 24 denotes a gas discharge line, and reference numerals 23 and 25. Indicates an open / close valve.
[0014]
In order to perform the cleaning treatment of the gas containing the contaminant using this unit adsorption device, first, the valve 25 is closed, the valve 23 is opened, and the contaminant is supplied through the gas supply line (supply pipe) 22. Is supplied into the container 21, and after supplying a predetermined amount of gas, the valve 23 is closed and left for a predetermined time. Thereby, the contaminants in the gas are adsorbed on the ACF sheet 14 (adsorption step).
[0015]
Next, after the operation of adsorbing the contaminants is completed, the valve 23 is closed, the valve 25 is opened, and the inside of the container 21 is evacuated through a gas exhaust line 24 connected to an exhaust pump (not shown). Then, a current is applied between the electrodes 12 and 13 via the lead wires 16 and 17. The energization generates heat in the rolled ACF sheet 14, and the heat generated causes the contaminants adsorbed on the rolled ACF sheet to be desorbed (desorbed) (desorption step). In this case, since the inside of the container 21 is evacuated, the contaminants can be quickly and efficiently desorbed. In this case, the pressure in the container is preferably maintained at about 200 to 1 Torr. The heat generation temperature is appropriately selected according to the contaminants adsorbed on the ACF sheet, but is generally about 80 to 180 ° C.
[0016]
After completion of the desorption step, a cycle consisting of the adsorption operation and the desorption operation is repeatedly performed to adsorb contaminants to the roll-shaped wound body of the ACF sheet and to remove contaminants from the roll-shaped winding. Separation can be performed alternately. The roll-shaped wound body of the ACF sheet after the contaminants are detached is a regenerated one having a good adsorption ability to the contaminants.
[0017]
FIG. 4 shows an example in which the rolled wound body of the ACF sheet is arranged in the airtight container 21. However, the plate-like laminate of the ACF sheet shown in FIG. You can also.
The shape of the container 21 is not particularly limited, and may be a cylindrical body, a box, or the like.
[0018]
For the purification of the gas containing contaminants according to the present invention, a plurality (usually 2 to 4, preferably 2 to 3) of the unit adsorption devices described above are used. At least one of them uses this as an apparatus for an adsorption step, and at least one uses it as an apparatus for a desorption step. In this way, by performing the adsorption step and the desorption step in the same manner using a plurality of unit adsorption devices, the gas containing contaminants can be continuously cleaned.
[0019]
Next, the present invention will be described in more detail with reference to the drawings.
FIG. 5 shows an example of a flow sheet for implementing the method of the present invention.
In FIG. 5, reference numerals 21 and 21 'denote hermetic containers, reference numerals 14 and 14' denote ACF sheets (wound bodies), reference numerals 12, 13, 12 'and 13' electrodes, and reference numerals 16, 17, 16 'and 17' lead wires. , 22, 22 ′ are gas supply lines, 24, 24 ′ are gas discharge lines, 23, 25, 23 ′ 25 ′ are open / close valves, 31 is a gas line containing contaminants, 32 is an exhaust line (contaminant line). ) And 33 are exhaust pumps, 34 is a contaminant line, 35 is a cooler, 36 is a liquid coolant discharge line, 43 is a power supply, 41, 42, 41 'and 42' are switches. A and B show unit adsorption apparatuses. The unit suction devices A and B need not always have the same shape and size, but may have different shapes and sizes.
Both the valves and switches are operated by a control device (computer or the like).
[0020]
In order to purify the gas containing contaminants according to the flow sheet shown in FIG. 5, first, the adsorption process is performed using the unit adsorption device A, and the desorption process is performed using the unit adsorption device B.
That is, in a state where the valve 23 is opened, the valve 25 is closed, and the switches 41 and 42 are turned off, the gas is supplied from the contaminant gas line 31 via the line 22 and the valve 23 to the container 21 of the unit adsorption apparatus A. And a predetermined amount of gas is supplied into the container 21 (adsorption step).
On the other hand, in a state where the valve 23 ′ is closed and the valve 25 ′ is opened, the switch 41 ′ and the switch 42 ′ are turned on, and the exhaust pump 33 is turned inside the container 21 ′ via the line 24 ′ and the line 32. While the air is exhausted by using the electrode, a current is supplied between the electrodes 12 'and 13' of the ACF sheet (winded body) 14 'to generate heat in the ACF sheet. Due to this heat, the contaminants adsorbed on the ACF sheet 14 'are desorbed, and the contaminants are introduced into the cooler 35 via the valve 25', the line 24 ', the line 32, the exhaust pump 33, and the line 34. Where it is cooled and condensed and liquefied. The liquefaction is recovered through line 36.
After the completion of the adsorption step by the unit adsorption device A and the desorption step by the unit adsorption device B, on the contrary, the unit adsorption device A is operated as the desorption process, and the unit adsorption device B is operated as the adsorption process.
As described above, the adsorption step and the desorption step are alternately performed in the unit adsorption apparatus A, and the desorption step and the adsorption step are alternately performed in the unit adsorption apparatus B, thereby continuously purifying the pollutant-containing gas. It can be done either intermittently or intermittently. The contaminants contained in the gas can be recovered as liquefied substances.
[0021]
The gas containing contaminants includes air and other gases (such as nitrogen gas). The contaminants include, in addition to organic solvents (benzene, toluene, trichlene, HCFCs, MEK, alcohols), sulfur dioxide (SOx), nitrogen oxide (NOx), and the like. The concentration of the contaminant in the gas is usually about 1 ppm to 5 vol%.
[0022]
【Example】
Next, the present invention will be described in more detail by way of examples.
[0023]
Example 1
According to the flow sheet shown in FIG. 5, air containing 1000 ppm of toluene as a contaminant was purified. The main operating conditions in this case are shown below.
(1) Configuration of unit adsorption devices A and B (i) ACF sheet (rolled roll of ACF felt), manufactured by Toho Tenax Co., Ltd., product name "Fine Guard", roll length (height): 25 cm, roll Outer diameter: 18cm, Roll inner diameter: 10cm
(Ii) Container 21
Cylindrical body (height: 57cm, inner diameter: 27cm)
(2) Unit adsorption device A
(I) Temperature: 40 ° C
(Ii) Pressure: 1 atm (3) Unit adsorption device B
(I) Voltage between electrodes: 13V
(Ii) Current between electrodes: 50A
(Iii) Temperature: 180 ° C
(Iv) Pressure: 10 Torr (4) Line 31
(I) Flow rate: 1 m ³ / min
(5) Line 32
(I) Recovery amount of contaminant toluene: 0.16 kg / h
(6) Cooler 35
(I) Temperature: 20 ° C
[0024]
【The invention's effect】
ADVANTAGE OF THE INVENTION According to this invention, the contaminant contained in gas can be removed quickly and efficiently without using steam.
[Brief description of the drawings]
FIG. 1 shows an illustration of one embodiment of an activated carbon fiber sheet.
FIG. 2 shows an explanatory view of another embodiment of the activated carbon fiber sheet.
FIG. 3 is an explanatory view of a roll-shaped wound body of an activated carbon fiber sheet having tape-shaped electrodes attached to both side ends.
a: explanatory view of formation of a wound body b: explanatory view of the structure of a wound body FIG. 4 shows an explanatory view of an example of a unit suction device.
FIG. 5 shows an example of a flow sheet when carrying out the method of the present invention.
[Explanation of symbols]
Reference Signs List 10 Activated carbon fiber sheet 12, 13 Electrode 14 Rolled wound body of activated carbon fiber sheet 16, 17 Lead wire 33 Exhaust pump 35 Coolers 41, 42, 41 ', 42' Switch 43 Power supply

Claims (4)

In order to purify gas containing contaminants, adsorption is performed by combining at least two unit adsorption devices each having a closed container having two electrodes and having an activated carbon fiber sheet generating heat upon energization disposed therein. A method using an apparatus system, wherein an adsorbing step of adsorbing contaminants in the gas to the activated carbon fiber sheet in at least one of the unit adsorption devices; and adsorbing the activated carbon fiber sheet in at least one of the unit adsorption devices. The method includes a desorption step of desorbing the adsorbed contaminants, and the adsorption step is performed by supplying the contaminant-containing gas to the unit adsorption device, and the desorption step exhausts the inside of the unit adsorption device. A method for cleaning gas containing contaminants, wherein the method is performed by causing electricity to flow between the electrodes to generate heat in the activated carbon fiber sheet. The method according to claim 1, wherein the activated carbon fiber sheet is a roll-shaped wound body. An apparatus for purifying a gas containing contaminants,
(I) having a plurality of unit adsorption devices each having a closed container having two electrodes and having therein an activated carbon fiber sheet that generates heat when energized;
(Ii) a gas supply pipe having an open / close valve is provided in the airtight container;
(Iii) a gas exhaust pipe connected to an exhaust system via a closed valve is connected to the airtight container;
(Iv) a lead wire for energization is connected to the electrode of the activated carbon fiber sheet;
(V) the lead wire is connected to a power supply circuit via a switch circuit;
(Vi) having a control device for operating the open / close valve;
(Vii) having a control device for operating the switch circuit;
An apparatus for purifying gas containing contaminants. The apparatus according to claim 3, wherein the activated carbon fiber sheet is a roll-shaped wound body.

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