VOC removal method

Abstract

The present invention removes VOC adsorbed on a VOC adsorption rotor with high energy efficiency. In the VOC removal method using a VOC adsorption rotor (10) provided with a honeycomb structure carrying an adsorbent for adsorbing VOC and provided with an adsorption zone (Z1), a separation zone (Z2), and a cooling zone (Z3) in the rotation direction, a gas to be treated is passed through the adsorption zone (Z1) of the VOC adsorption rotor (10), thereby adsorbing VOC contained in the gas to be treated. The gas is passed through the desorption zone (Z2) to desorb the VOC adsorbed in the adsorption zone (Z1), the honeycomb structure heated in the desorption zone (Z2) is cooled in the cooling zone (Z3), and a current is passed through the honeycomb structure containing metal in the desorption zone (Z2) to heat the honeycomb structure.

Description

Technical Field

[0001] The present invention relates to a method for removing VOC contained in a treatment target gas. Background Art

[0002] Conventionally, there is a known technique for removing VOCs contained in a treatment target gas using a honeycomb VOC adsorption rotor that adsorbs VOCs (see Patent Document 1). Conventional VOC adsorption rotors use ceramics, glass, etc. as a substrate and carry an adsorbent that adsorbs VOCs.

[0003] The VOC adsorption rotor is provided with an adsorption zone for adsorbing VOC contained in the treatment target gas, a desorption zone for desorbing VOC adsorbed in the adsorption zone by passing the heated gas, and a cooling zone for cooling the VOC adsorption rotor heated in the desorption zone. That is, during one rotation of the VOC adsorption rotor, VOC is adsorbed in the adsorption zone, VOC is desorbed in the desorption zone, and the rotor is cooled in the cooling zone. Furthermore, the VOC is adsorbed again in the adsorption zone.

[0004] Prior Art Literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Publication No. 2016-77969 Summary of the invention

[0007] Problem that the invention aims to solve

[0008] Conventional VOC adsorption rotors heat gas to desorb VOC adsorbed in the adsorption zone and pass the heated gas through the desorption zone. Therefore, the energy efficiency for desorbing VOC is not high and there is room for improvement.

[0009] The present invention is an invention that solves the above-mentioned problems, and an object of the present invention is to provide a VOC removal method capable of desorbing VOC adsorbed on a VOC adsorption rotor with high energy efficiency.

[0010] Technical solutions to solve problems

[0011] The VOC removal method of the present invention uses a VOC adsorption rotor, which has a honeycomb structure carrying an adsorbent for adsorbing VOCs, and is provided with an adsorption zone, a desorption zone, and a cooling zone along the rotation direction, and is characterized in that:

[0012] The VOC contained in the gas to be treated is adsorbed by passing the gas to be treated through the adsorption zone of the VOC adsorption rotor, and the gas is passed through the desorption zone to desorb the VOC adsorbed in the adsorption zone, and the honeycomb structure heated in the desorption zone is cooled in the cooling zone.

[0013] In the detachment zone, an electric current is passed through the honeycomb structure body including metal, thereby heating the honeycomb structure body.

[0014] Effects of the Invention

[0015] According to the VOC removal method of the present invention, in the desorption zone, electric current is passed through the metal honeycomb structure to generate Joule heat, thereby directly heating the honeycomb structure, thereby desorption of adsorbed VOCs with high energy efficiency in the desorption zone. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a perspective view schematically showing the structure of a VOC removal device as an example of a device for realizing the VOC removal method in one embodiment.

[0017] Figure 2 It is a plan view schematically showing the structure of the VOC adsorption rotor when viewed in the extending direction of the rotation shaft. DETAILED DESCRIPTION

[0018] Hereinafter, embodiments of the present invention will be shown, and features of the present invention will be specifically described.

[0019] Figure 1 1 is a perspective view schematically showing the structure of a VOC removal device 100 as an example of a device for implementing a VOC removal method in one embodiment. However, the structure for implementing a VOC removal method in one embodiment is not limited to Figure 1 The VOC removal device 100 is shown.

[0020] The VOC removal device 100 includes a VOC adsorption rotor 10, a pair of electrodes 20a, 20b, and a voltage application device 30. Figure 1 As shown, the VOC removal device 100 may further include a first air supply device 41 , a second air supply device 42 , a third air supply device 43 , and a heating device 44 .

[0021] Figure 2 1 is a schematic top view showing the structure of the VOC adsorption rotor 10 when viewed in the extending direction of the rotation shaft 11 (hereinafter, sometimes referred to as the rotation shaft direction). Figure 2The electrode 20a described later is also shown. The VOC adsorption rotor 10 is driven by a motor or the like and is configured to be rotatable around a rotating shaft 11. The diameter of the VOC adsorption rotor 10 is, for example, greater than 500 mm and less than 2000 mm, and the dimension of the rotating shaft 11 in the extension direction is, for example, greater than 200 mm and less than 800 mm.

[0022] The VOC adsorption rotor 10 includes a honeycomb structure 1 carrying an adsorbent for adsorbing VOC. The honeycomb structure 1 includes a metal such as stainless steel. However, the metal constituting the honeycomb structure 1 is not limited to stainless steel. In addition, the VOC adsorption rotor 10 may be configured to include a metal as a whole, or a portion other than the honeycomb structure 1 may be composed of a material other than metal.

[0023] The shapes of the plurality of cells 2 constituting the honeycomb structure 1 can be any shapes. Figure 2 In the example shown, the cell 2 is triangular in shape when viewed in the extending direction of the rotation axis 11. However, the cell 2 may be hexagonal, rectangular or other shapes when viewed in the rotation axis direction.

[0024] The adsorbent carried on the honeycomb structure 1 can be any adsorbent as long as it can adsorb VOC contained in the treatment target gas, for example, zeolite, activated carbon, silica, etc. can be used. The treatment target gas is, for example, a gas containing VOC generated by cleaning, printing, coating, drying, etc. in a factory. In addition, the present invention is not limited by the type of VOC to be removed or the type of adsorbent.

[0025] A catalyst for decomposing VOC may be supported on the honeycomb structure 1. As the catalyst for decomposing VOC, for example, platinum, palladium, etc. can be used.

[0026] like Figure 1 as well as Figure 2 As shown, the VOC adsorption rotor 10 is provided with an adsorption zone Z1, a desorption zone Z2, and a cooling zone Z3 along the rotation direction. The range of the adsorption zone Z1 in the rotation direction is, for example, a range of 230° to 270°, the range of the desorption zone Z2 is, for example, a range of 30° to 60°, and the range of the cooling zone Z3 is, for example, a range of 30° to 60°.

[0027] The adsorption zone Z1 is a region for passing the process target gas to adsorb VOC contained in the process target gas. In the present embodiment, the process target gas is blown by the first blower 41 .

[0028] The separation zone Z2 is a zone for separating the VOC adsorbed in the adsorption zone Z1. In the present invention, as described later, a current is passed through the honeycomb structure 1, thereby passing gas through the honeycomb structure 1 in a heated state, thereby separating the VOC. The gas passing through the separation zone Z2 may also be an unheated gas, but in order to more effectively separate the VOC, it is preferred to use a heated gas. Here, the case where the heated gas passes through the separation zone Z2 is described. That is, in Figure 1 In the VOC removal device 100 shown, the gas blown by the second air supply device 42 is heated by a heating device 44 such as a heater, and then sent to the desorption zone Z2.

[0029] The cooling zone Z3 is a region for cooling the honeycomb structure 1 heated in the separation zone Z2. In the present embodiment, the third air supply device 43 supplies gas for cooling the honeycomb structure 1 to the cooling zone Z3.

[0030] The gas from which VOC is removed by passing through the adsorption zone Z1 may be returned to the exhaust source of the treatment target gas. The gas warmed by passing through the cooling zone Z3 may be used as the gas passing through the desorption zone Z2.

[0031] exist Figure 2 In the embodiment, if the VOC adsorption rotor 10 rotates counterclockwise, the cells 2 in the adsorption zone Z1 move to the desorption zone Z2 and the cooling zone Z3 in sequence, and then return to the adsorption zone Z1. The honeycomb structure 1 is cooled in the cooling zone Z3, so that VOC can be adsorbed again in the adsorption zone Z1.

[0032] That is, the VOC adsorption rotor 10 rotates, thereby repeatedly adsorbing and desorbing the VOC contained in the treatment target gas. In addition, when the honeycomb structure 1 carries a catalyst for decomposing VOC, in the desorption zone Z2, although the decomposition reaction of VOC is carried out, the adsorbed VOC can be captured and desorbed due to the decomposition of VOC, so it is assumed that the decomposition of VOC is included in the desorption of VOC. The rotation speed of the VOC adsorption rotor 10 is, for example, 8.4 rph or more and 11.0 rph or less.

[0033] The VOC removal method in the present embodiment includes a step of passing a treatment target gas through an adsorption zone Z1 to adsorb VOC contained in the treatment target gas, passing the gas through a desorption zone Z2 to desorb VOC adsorbed in the adsorption zone Z1, and cooling the honeycomb structure 1 heated in the desorption zone Z2 in a cooling zone Z3, wherein an electric current is passed through the honeycomb structure 1 containing metal in the desorption zone Z2 to heat the honeycomb structure 1. The electric current is passed through the honeycomb structure 1 to generate Joule heat, so that the honeycomb structure 1 can be directly heated in the desorption zone Z2. Thus, the amount of energy used to desorb VOC in the desorption zone Z2 can be reduced.

[0034] That is, the VOC removal method in this embodiment has a better heating efficiency than the conventional method of simply passing the heated gas through the desorption zone Z2 to desorb VOC adsorbed on the honeycomb structure 1, and can desorb VOC adsorbed on the VOC adsorption rotor 10 with high energy efficiency.

[0035] Furthermore, when current is passed through the honeycomb structure 1 to heat the honeycomb structure 1 and the heated gas is passed through the desorption zone Z2, for example, the heating temperature of the gas passing through the desorption zone Z2 can be lowered compared with the above-mentioned conventional method.

[0036] In order to make the current flow through the honeycomb structure 1 in the separation zone Z2, for example, a voltage may be applied to the honeycomb structure 1 in the separation zone Z2. In this case, a voltage may be applied to the honeycomb structure 1 in the separation zone Z2 from both outer sides in the extending direction of the rotation axis 11 of the VOC adsorption rotor 10. Figure 1 In the voltage applying device 100 shown, a method of applying voltage to the honeycomb structure 1 in the desorption zone Z2 from both outer sides in the extending direction of the rotating shaft 11 of the VOC adsorption rotor 10 will be described.

[0037] The pair of electrodes 20a and 20b are arranged at positions in contact with the VOC adsorption rotor 10 on both outer sides of the VOC adsorption rotor 10 in the extending direction of the rotation axis 11 of the VOC adsorption rotor 10. The pair of electrodes 20a and 20b are preferably arranged at positions opposite to each other in the extending direction of the rotation axis 11. The pair of electrodes 20a and 20b are arranged in the desorption zone Z2 among the adsorption zone Z1, the desorption zone Z2, and the cooling zone Z3 of the VOC adsorption rotor 10. In more detail, as Figure 1 as well as Figure 2 As shown, a pair of electrodes 20a, 20b is arranged at a position close to the adsorption zone Z1 in the detachment zone Z2.

[0038] The pair of electrodes 20a and 20b are made of graphite, for example. However, the material of the pair of electrodes 20a and 20b is not limited to graphite, and metals such as copper may also be used.

[0039] In the present embodiment, the pair of electrodes 20a and 20b each have a shape extending in the radial direction of the VOC adsorption rotor 10. The pair of electrodes 20a and 20b have a shape extending in the radial direction, so that when a voltage is applied to the pair of electrodes 20a and 20b by a voltage applying device 30 described later, a wide area in the radial direction of the honeycomb structure 1 can be heated. Figure 1 as well as Figure 2 As shown, the pair of electrodes 20a, 20b are elongated in shape so as not to become an obstacle when the heated gas passes through the separation zone Z2.

[0040] However, the shape of the pair of electrodes 20a, 20b is not limited to Figure 1 as well as Figure 2 For example, the pair of electrodes 20a, 20b may be in the shape of a roller whose surface in contact with the VOC adsorption rotor 10 is a rotating surface.

[0041] As described above, the pair of electrodes 20a and 20b are respectively provided at positions in contact with the VOC adsorption rotor 10. Therefore, the VOC adsorption rotor 10 rotates while rubbing against the pair of electrodes 20a and 20b while maintaining the contact state.

[0042] The voltage applying device 30 can apply voltage to the pair of electrodes 20a and 20b. For example, the voltage applying device 30 applies voltage to the pair of electrodes 20a and 20b so that the output becomes 2 kW or more and 10 kW or less. By applying voltage to the pair of electrodes 20a and 20b by the voltage applying device 30, a current can flow through the honeycomb structure 1 containing metal in the separation zone Z2, and the honeycomb structure 1 can be directly heated.

[0043] As described above, by applying voltage to the honeycomb structure 1 in the separation zone Z2 from both outer sides in the extending direction of the rotation axis 11 of the VOC adsorption rotor 10, the honeycomb structure 1 can be efficiently heated in the extending direction of the rotation axis 11. In addition, by applying voltage to a pair of electrodes 20a and 20b arranged at positions in contact with the VOC adsorption rotor 10 on both outer sides in the extending direction of the rotation axis 11 relative to the VOC adsorption rotor 10, voltage can be easily applied from both outer sides in the extending direction of the rotation axis 11 of the VOC adsorption rotor 10.

[0044] The present invention is not limited to the above-mentioned embodiment, and various applications and modifications can be applied within the scope of the present invention. For example, as an example of a method for causing a current to flow through the honeycomb structure 1 containing metal in the separation zone Z2, an example of applying a voltage to the honeycomb structure 1 is cited, but the current can also be caused to flow by other methods.

[0045] In the above embodiment, an example is given in which voltage is applied to the honeycomb structure 1 in the desorption zone Z2 from both outer sides in the extending direction of the rotation shaft 11 of the VOC adsorption rotor 10. However, voltage may be applied to other positions of the honeycomb structure 1 in the desorption zone Z2.

[0046] In the above-mentioned embodiment, the case where the gas for cooling the honeycomb structure 1 passes through the cooling zone Z3 to cool the honeycomb structure 1 in the cooling zone Z3 is described, but the honeycomb structure 1 in the cooling zone Z3 may be cooled by other methods.

[0047] In the above-mentioned VOC removal device 100, the case where the pair of electrodes 20a and 20b arranged in the separation zone Z2 is one group is described, but multiple groups may be arranged and voltages may be applied to the multiple groups of electrodes. In this case, a wide range of the honeycomb structure 1 in the separation zone Z2 can be heated at once.

[0048] Description of Reference Numerals

[0049] 1: Honeycomb structure;

[0050] 2: Small room;

[0051] 10: VOC adsorption rotor;

[0052] 11: Rotation axis;

[0053] 20a, 20b: a pair of electrodes;

[0054] 30: voltage applying device;

[0055] 41: 1st air supply device;

[0056] 42: second air supply device;

[0057] 43: The third air supply device;

[0058] 44: Heating device;

[0059] 100: VOC removal device;

[0060] Z1: adsorption zone;

[0061] Z2: Detachment zone;

[0062] Z3: Cooling zone.

Claims

1. A VOC removal method using a VOC adsorption rotor, wherein the VOC adsorption rotor has a honeycomb structure carrying an adsorbent for adsorbing VOCs, and is provided with an adsorption zone, a desorption zone, and a cooling zone along a rotation direction, characterized in that: The VOC contained in the gas to be treated is adsorbed by passing the gas to be treated through the adsorption zone of the VOC adsorption rotor, and the gas is passed through the desorption zone to desorb the VOC adsorbed in the adsorption zone, and the honeycomb structure heated in the desorption zone is cooled in the cooling zone. In the detachment zone, an electric current is passed through the honeycomb structure body including metal, thereby heating the honeycomb structure body.

2. The VOC removal method according to claim 1, characterized in that: In the separation zone, a voltage is applied to the honeycomb structure, thereby causing an electric current to flow through the honeycomb structure.

3. The VOC removal method according to claim 2, characterized in that: A voltage is applied to the honeycomb structure in the desorption zone from both outer sides in the extending direction of the rotation axis of the VOC adsorption rotor.

4. The VOC removal method according to claim 3, characterized in that: A voltage is applied to a pair of electrodes disposed at positions in contact with the VOC adsorption rotor on both outer sides of the VOC adsorption rotor in the extending direction of the rotation axis of the VOC adsorption rotor.

Images