VOC adsorption rotor

Abstract

Provided is a VOC adsorption rotor that makes desorption of an adsorbed VOC possible with high energy efficiency.　This VOC adsorption rotor 10 comprises a honeycomb structure 1 that supports an adsorption agent for VOC adsorption, and the honeycomb structure 1 is composed of a metal.

Description

VOC adsorption rotor

[0001] The present invention relates to a VOC adsorption rotor for adsorbing VOCs contained in a gas to be treated.

[0002] Conventionally, honeycomb-type VOC adsorption rotors that adsorb volatile organic compounds (VOCs) have been known. Conventional VOC adsorption rotors use ceramic, glass, or the like as a substrate, and carry an adsorbent that adsorbs VOCs. Patent Document 1 discloses a gas treatment device equipped with such a VOC adsorption rotor.

[0003] The VOC adsorption rotor is provided with an adsorption zone that adsorbs VOCs contained in the gas to be treated, a desorption zone that desorbs the VOCs adsorbed in the adsorption zone by passing heated gas through it, and a cooling zone that cools the VOC adsorption rotor heated in the desorption zone. That is, during one rotation of the VOC adsorption rotor, adsorption of VOCs is performed in the adsorption zone, desorption of VOCs is performed in the desorption zone, and cooling is performed in the cooling zone. Then, VOCs are adsorbed again in the adsorption zone.

[0004] JP 2016-77969 A

[0005] Conventional VOC adsorption rotors heat gas and pass the heated gas through the desorption zone to desorb the VOCs adsorbed in the adsorption zone, so the energy efficiency for desorbing VOCs cannot be said to be high, and there is room for improvement.

[0006] The present invention is intended to solve the above-mentioned problems, and has an object to provide a VOC adsorption rotor that can desorb adsorbed VOCs with high energy efficiency.

[0007] The VOC adsorption rotor of the present invention is a VOC adsorption rotor including a honeycomb structure supporting an adsorbent for adsorbing VOCs, characterized in that the honeycomb structure is made of metal.

[0008] In the VOC adsorption rotor of the present invention, the honeycomb structure supporting the adsorbent for adsorbing VOCs is made of metal and can be electrically conductive. Therefore, for example, in the desorption zone, the honeycomb structure can be directly heated by passing an electric current through it to generate Joule heat, making it possible to desorb the adsorbed VOCs with high energy efficiency.

[0009] [Correction based on Rule 91, June 26, 2023] This is a perspective view schematically illustrating the configuration of a VOC adsorption rotor in one embodiment. This is a plan view schematically illustrating the configuration of a VOC adsorption rotor in one embodiment, as viewed in the direction of the rotation axis. This is a diagram for explaining that a pair of electrodes in contact with the VOC adsorption rotor are arranged on both outer sides of the VOC adsorption rotor in the rotation axis direction in the desorption zone, and a voltage is applied to the electrodes. (a) is a diagram showing a first microscopic shape reproduction model that is a model of a honeycomb structure, and (b) is a diagram showing a first uniform equivalent property model corresponding to the first microscopic shape reproduction model. (a) is a diagram showing a second microscopic shape reproduction model that is a model of a honeycomb structure, and (b) is a diagram showing a second uniform equivalent property model corresponding to the second microscopic shape reproduction model. 1A is a graph showing the normalized conductivity in the X-axis direction and the normalized conductivity in the Y-axis direction versus (2Lb / La), and FIG. 1B is a graph showing the same graph as FIG. 1A with the vertical axis of FIG. 1A as a logarithmic axis. 1A is a diagram showing the simulation results of the temperature distribution when a first uniform equivalent property model is used, and FIG. 1B is a diagram showing the simulation results of the temperature distribution when a second uniform equivalent property model is used. 1C is a perspective view showing four blocks stacked in a top-bottom, left-right arrangement.

[0010] The features of the present invention will be specifically described below by showing embodiments of the present invention.

[0011] Fig. 1 is a perspective view showing a VOC adsorption rotor 10 according to one embodiment. Fig. 2 is a plan view showing the VOC adsorption rotor 10 according to one embodiment, as viewed in the direction of extension of the rotary shaft 11 (hereinafter also referred to as the rotary shaft direction).

[0012] The VOC adsorption rotor 10 is configured to be rotatable around a rotary shaft 11 using a motor or the like as a drive source. The diameter of the VOC adsorption rotor 10 is, for example, 500 mm or more and 2000 mm or less, and the dimension in the extension direction of the rotary shaft 11 is, for example, 200 mm or more and 800 mm or less.

[0013] The VOC adsorption rotor 10 includes a honeycomb structure 1 that supports an adsorbent for adsorbing VOCs. The honeycomb structure 1 is made of a metal such as stainless steel. However, the metal that constitutes the honeycomb structure 1 is not limited to stainless steel. The VOC adsorption rotor 10 may be entirely made of metal, or a portion other than the honeycomb structure 1 may be made of a material other than metal.

[0014] The shape of the plurality of cells 2 constituting the honeycomb structure 1 can be any shape. In the example shown in Fig. 2, the shape of the cells 2 when viewed in the extension direction of the rotation axis 11 is triangular. However, the shape of the cells 2 when viewed in the rotation axis direction may be other shapes such as hexagonal or rectangular.

[0015] The adsorbent supported on the honeycomb structure 1 may be any material capable of adsorbing VOCs contained in the gas to be treated, and examples thereof include zeolite, activated carbon, and silica. The gas to be treated is, for example, a gas containing VOCs generated by processes such as cleaning, printing, painting, and drying in a factory. The present invention is not limited by the type of VOC to be removed or the type of adsorbent.

[0016] A catalyst for decomposing VOCs may be supported on the honeycomb structure 1. For example, platinum, palladium, or the like can be used as the catalyst for decomposing VOCs.

[0017] 1 and 2, 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, from 230° to 270°, the range of the desorption zone Z2 is, for example, from 30° to 60°, and the range of the cooling zone Z3 is, for example, from 30° to 60°.

[0018] The adsorption zone Z1 is a region through which the gas to be treated is passed to adsorb the VOCs contained in the gas to be treated. The desorption zone Z2 is a region through which the VOCs adsorbed in the adsorption zone Z1 are desorbed. A heated gas is passed through the desorption zone Z2 to desorb the VOCs. The cooling zone Z3 is a region for cooling the honeycomb structure 1 heated in the desorption zone Z2. A gas for cooling the honeycomb structure 1 is passed through the cooling zone Z3.

[0019] The gas from which VOCs have been removed by passing through the adsorption zone Z1 may be returned to the source of the gas to be treated. Also, the gas warmed by passing through the cooling zone Z3 may be used as the gas to be passed through the desorption zone Z2.

[0020] 2, when the VOC adsorption rotor 10 rotates counterclockwise, the cells 2 located in the adsorption zone Z1 move in order to the desorption zone Z2 and the cooling zone Z3, and then return to the adsorption zone Z1. The honeycomb structure 1 is cooled in the cooling zone Z3, so that it can adsorb VOCs again in the adsorption zone Z1.

[0021] That is, as the VOC adsorption rotor 10 rotates, adsorption and desorption of VOCs contained in the gas to be treated are repeated. If a catalyst for decomposing VOCs is supported on the honeycomb structure 1, a VOC decomposition reaction occurs in the desorption zone Z2. However, since the decomposition of VOCs can be considered to result in the desorption of adsorbed VOCs, the decomposition of VOCs is considered to be included in the desorption of VOCs. The rotation speed of the VOC adsorption rotor 10 is, for example, 8.4 rph or more and 11.0 rph or less.

[0022] As described above, the honeycomb structure 1 is made of metal and is therefore electrically conductive. Therefore, in the desorption zone Z2, the honeycomb structure 1 can be directly heated by passing an electric current through the honeycomb structure 1 to generate Joule heat. For example, as shown in FIG. 3 , a pair of electrodes 20a, 20b in contact with the VOC adsorption rotor 10 are disposed on both outer sides of the VOC adsorption rotor 10 in the axial direction of the rotation of the VOC adsorption rotor 10 in the desorption zone Z2. During rotation of the VOC adsorption rotor 10, the VOC adsorption rotor 10 rotates while rubbing against the pair of electrodes 20a, 20b and maintaining contact therewith. In this state, a voltage is applied between the pair of electrodes 20a, 20b to pass an electric current through the honeycomb structure 1. This allows the honeycomb structure 1 to be directly heated in the desorption zone Z2.

[0023] As described above, the VOC adsorption rotor 10 of this embodiment can directly heat the honeycomb structure 1 by passing an electric current through the honeycomb structure 1 in the desorption zone Z2, thereby reducing the amount of energy required to desorb VOCs. That is, compared to conventional VOC adsorption rotors that desorb VOCs adsorbed in the honeycomb structure 1 simply by passing heated gas through the desorption zone Z2, the VOC adsorption rotor 10 has better heating efficiency and can desorb adsorbed VOCs with high energy efficiency. For example, in order to desorb VOCs adsorbed in the adsorption zone Z1, the heating temperature of the gas passing through the desorption zone Z2 can be reduced compared to the conventional VOC adsorption rotor described above.

[0024] Here, the shape of the cells 2 constituting the honeycomb structure 1 was changed, and the conductivity of the honeycomb structure 1 was investigated by simulation. Here, two types of models were created as honeycomb structures 1 having different shapes of the cells 2: a first microscopic shape reproduction model 21 shown in FIG. 4(a) and a second microscopic shape reproduction model 23 shown in FIG. 5(a). In addition, for use in the simulation, a first uniform equivalent property model 22 (FIG. 4(b)) corresponding to the first microscopic shape reproduction model 21 and a second uniform equivalent property model 24 (FIG. 5(b)) corresponding to the second microscopic shape reproduction model 23 were created.

[0025] The X-axis direction, Y-axis direction, and Z-axis direction of the first homogeneous equivalent property model 22 shown in FIG. 4(b) and the second homogeneous equivalent property model 24 shown in FIG. 5(b) correspond to the circumferential direction, radial direction, and rotational axis direction of the VOC adsorption rotor 10, respectively.

[0026] In the first microscopic shape reproduction model 21 shown in FIG. 4( a), the dimension La in the circumferential direction of the cell 2 is 3.3 mm, the dimension Lb in the radial direction is 2.0 mm, the dimension Ld (not shown) in the rotation axis direction is 0.05 mm, and the conductivity σ of the honeycomb structure 1 is 1 / (142×10 8 ) S / m, and the resistances in the X-axis direction, Y-axis direction, and Z-axis direction of the first microshape reproduction model 21 and the first uniform equivalent physical property model 22 when the dimension in the Z-axis direction of the first uniform equivalent physical property model 22 is 0.1 mm are shown in Table 1.

[0027]

[0028] As shown in Table 1, the resistance in the X-axis direction of the first uniform equivalent physical property model 22 has an error of 10% or less compared to the resistance in the X-axis direction of the first microscopic shape reproduction model 21. Similarly, the resistance in the Y-axis direction and the Z-axis direction of the first uniform equivalent physical property model 22 has an error of 10% or less compared to the resistance in the Y-axis direction and the Z-axis direction of the first microscopic shape reproduction model 21. Therefore, when performing a simulation, it is possible to use the first uniform equivalent physical property model 22, which is a simplified model, instead of the first microscopic shape reproduction model 21.

[0029] In the second microscopic shape reproduction model 23 shown in FIG. 5( a), the dimension La in the circumferential direction of the cell 2 is 1.0 mm, the dimension Lb in the radial direction is 10.0 mm, the dimension Ld (not shown) in the rotation axis direction is 0.05 mm, and the conductivity σ of the honeycomb structure 1 is 1 / (142×10 8 ) S / m, and the resistances in the X-axis direction, Y-axis direction, and Z-axis direction of the second microscopic shape reproduction model 23 and the second uniform equivalent physical property model 24 when the dimension in the Z-axis direction of the second uniform equivalent physical property model 24 is 0.1 mm are shown in Table 2.

[0030]

[0031] As shown in Table 2, the resistance in the X-axis direction of the second uniform equivalent physical property model 24 has an error of 10% or less compared to the resistance in the X-axis direction of the second microscopic shape reproduction model 23. Similarly, the resistance in the Y-axis direction and the Z-axis direction of the second uniform equivalent physical property model 24 has an error of 10% or less compared to the resistance in the Y-axis direction and the Z-axis direction of the second microscopic shape reproduction model 23. Therefore, when performing a simulation, it is possible to use the second uniform equivalent physical property model 24, which is a simplified model, instead of the second microscopic shape reproduction model 23.

[0032] In the first homogeneous equivalent property model 22 and the second homogeneous equivalent property model 24, the conductivity in the X-axis direction, the conductivity in the Y-axis direction, and the conductivity in the Z-axis direction are expressed by the following equations (1) to (3): Conductivity in the X-axis direction = Ld / Lb × σ[1 + 1 / √(1 + (2Lb / La) 2 )] (1) Conductivity in the Y-axis direction = Ld / Lb × σ × (2Lb / La) / √(1 + (La / 2Lb) 2 ) (2) Conductivity in the Z-axis direction = Ld / Lb × σ [1 + √(1 + (2Lb / La) 2 )] (3) The conductivity in the Y-axis direction can also be expressed by the following equation (4): Conductivity in the Y-axis direction = Ld / Lb × σ × (2Lb / La) / [√(1 + (La / 2Lb) 2 )+La / 2Lb] (4)

[0033] When the conductivity in the X-axis direction and the conductivity in the Y-axis direction are normalized by setting the conductivity in the Z-axis direction to 1, the normalized conductivity in the X-axis direction and the normalized conductivity in the Y-axis direction each depend only on (2Lb / La).

[0034] Fig. 6(a) is a graph showing the normalized conductivity in the X-axis direction and the normalized conductivity in the Y-axis direction versus (2Lb / La). Fig. 6(b) is a graph similar to Fig. 6(a) in which the vertical axis is a logarithmic axis. Note that in Figs. 6(a) and 6(b), the horizontal axis is also a logarithmic axis. In Figs. 6(a) and 6(b), "X-axis direction" refers to the normalized conductivity in the X-axis direction, "Y-axis direction" refers to the normalized conductivity in the Y-axis direction, and "Z-axis direction" refers to the normalized conductivity in the Z-axis direction.

[0035] 6A and 6B, the conductivity in the X-axis direction and the conductivity in the Y-axis direction are equal to or less than the conductivity in the Z-axis direction. The conductivity in the X-axis direction and the conductivity in the Y-axis direction are in a trade-off relationship, and reducing one conductivity increases the other conductivity.

[0036] As shown in Fig. 3, when a voltage is applied to the VOC adsorption rotor 10 in the desorption zone Z2, the amount of heat generated in the radial direction of the VOC adsorption rotor 10 can be adjusted by adjusting the size of the pair of electrodes 20a, 20b. That is, by using a pair of electrodes 20a, 20b with a longer radial dimension, the amount of heat generated in the radial direction can be increased. Therefore, if the amount of heat generated in the circumferential direction of the VOC adsorption rotor 10, which is the direction of rotation when a voltage is applied to the VOC adsorption rotor 10, is large, the adsorbed VOCs can be effectively desorbed in the desorption zone Z2. In order to increase the amount of heat generated in the circumferential direction of the VOC adsorption rotor 10, it is necessary to reduce the electrical conductivity in the circumferential direction (X-axis direction). To achieve this, (2Lb / La) should be increased, as shown in Figs. 6(a) and 6(b). If (2Lb / La) is 4 or more, the conductivity in the X-axis direction corresponding to the circumferential direction is smaller than the conductivity in the Y-axis direction corresponding to the radial direction, so it is preferable that (2Lb / La) is 4 or more, that is, Lb / La is 2 or more. Furthermore, if (2Lb / La) is 6 or more, the conductivity in the X-axis direction corresponding to the circumferential direction becomes smaller, so it is more preferable that Lb / La is 3 or more.

[0037] Figure 7 shows the results of a simulation of the temperature distribution of the honeycomb structure 1 when a voltage is applied to a pair of electrodes 20a, 20b in contact with the VOC adsorption rotor 10, as shown in Figure 3, where (a) shows the temperature distribution when the first uniform equivalent property model 22 is used, and (b) shows the temperature distribution when the second uniform equivalent property model 24 is used.

[0038] Here, as shown in FIG. 7( c), four block bodies 25 using the first homogeneous equivalent property model 22 or the second homogeneous equivalent property model 24 were stacked vertically and horizontally, and the temperature distribution was investigated when a voltage was applied to a pair of electrodes 26 a, 26 b arranged opposite each other in the Z-axis direction for the four block bodies 25. The block body 25 shown in FIGS. 7( a) and 7(b) is the block body 25 located at the bottom right of the four block bodies 25 shown in FIG. 7(c). In the temperature distributions shown in FIGS. 7( a) and 7(b), the darker the color, the higher the temperature. That is, the black area has a higher temperature than the white area.

[0039] 7(a) and 7(b), when the second homogeneous equivalent property model 24 is used, the high temperature region is wider than when the first homogeneous equivalent property model 22 is used, and the temperature in the X-axis direction corresponding to the circumferential direction is higher over a wider range. In other words, in order to more effectively desorb adsorbed VOCs, the second fine shape reproduction model 23 (FIG. 5(a)), in which Lb / La is 10, is more preferable than the first fine shape reproduction model 21 (FIG. 4(a)), in which Lb / La is approximately 0.6.

[0040] The above-described simulation is for the case where the shape of the cell 2 when viewed in the extension direction of the rotation axis 11 is triangular, but the same applies to the case where the shape of the cell 2 is hexagonal or rectangular, and it is preferable that Lb / La is 2 or more, and it is more preferable that Lb / La is 3 or more.

[0041] The present invention is not limited to the above-described embodiment, and various applications and modifications can be made within the scope of the present invention.

[0042] The VOC adsorption rotors in the present application are as follows. <1>. A VOC adsorption rotor comprising a honeycomb structure supporting an adsorbent for adsorbing VOCs, wherein the honeycomb structure is made of metal. <2>. The VOC adsorption rotor according to <1>, wherein, when La is the circumferential dimension of a cell constituting the honeycomb structure and Lb is the radial dimension thereof, Lb / La is 2 or greater. <3>. The VOC adsorption rotor according to <1>, wherein, when La is the circumferential dimension of a cell constituting the honeycomb structure and Lb is the radial dimension thereof, Lb / La is 3 or greater. <4>. The VOC adsorption rotor according to <2> or <3>, wherein, when viewed in the extension direction of the rotation axis of the VOC adsorption rotor, the shape of the cells is triangular. <5>. The VOC adsorption rotor according to any one of <1> to <4>, wherein the metal is stainless steel.

[0043] REFERENCE SIGNS LIST 1 honeycomb structure 2 cell 10 VOC adsorption rotor 11 rotating shaft 20a, 20b pair of electrodes 21 first micro shape reproduction model 22 first uniform equivalent physical property model 23 second micro shape reproduction model 24 second uniform equivalent physical property model 25 block body 26a, 26b pair of electrodes Z1 adsorption zone Z2 desorption zone Z3 cooling zone

Claims

1. A VOC adsorption rotor having a honeycomb structure supporting an adsorbent for adsorbing VOCs, the honeycomb structure is made of metal, and the honeycomb structure is directly heated by directly passing an electric current through the honeycomb structure to generate Joule heat; A VOC adsorption rotor, characterized in that, when a circumferential dimension of a cell constituting the honeycomb structure is La and a radial dimension of the cell is Lb, Lb / La is 2 or more.

2. A VOC adsorption rotor as described in claim 1, characterized in that when the circumferential dimension of the cells constituting the honeycomb structure is La and the radial dimension is Lb, Lb / La is 3 or more.

3. A VOC adsorption rotor as described in claim 1 or claim 2, characterized in that when viewed in the extension direction of the rotation axis of the VOC adsorption rotor, the shape of the cells is triangular.

4. A VOC adsorption rotor as described in claim 1 or claim 2, characterized in that the metal is stainless steel.