Organic solvent recovery system

Abstract

An organic solvent recovery system has a recovery device (1), a dehydration device (2), and a return device (3). The dehydration device (2) includes: a dehydration material (202) that adsorbs moisture contained in a recovered solvent (113B) by contact with the recovered solvent (113B); one or more dehydration treatment tanks (203) that house the dehydration material (202); and a discharge mechanism that supplies the recovered solvent (113B) separated by a separator (113) to the dehydration treatment tank (203) and discharges a dehydrated solvent (E) obtained by dehydration of the recovered solvent (113B) by the dehydration material (202) from the dehydration treatment tank (203). The return device (3) supplies the recovered solvent (113B) to a layer of the recovered solvent (113B) of the separator (113) when returning the recovered solvent (113B) in the dehydration treatment tank (203) to the separator (113). According to the organic solvent recovery system, even when reoperation is performed, a dehydrated solvent from which moisture is sufficiently removed can be discharged.

Description

Technical Field

[0001] This disclosure relates to an organic solvent recovery system. Background Technology

[0002] The organic solvent recovery system employs a mechanism comprising a pair of treatment tanks for adsorbing organic solvents in the treated gas using adsorption materials, and a treated gas supply device and a desorption gas supply device for each treatment tank, and is configured to switch between an adsorption process for supplying the treated gas to the treatment tank and a desorption process for supplying the desorption gas.

[0003] Activated carbon fiber (ACF) is used as an adsorbent material in gas treatment devices, for example. ACF is excellent at adsorbing gases containing low concentrations of organic solvents, and is therefore used as an adsorbent material. For example, Japanese Patent Application Publication No. 2014-147864 (Patent Document 1) discloses a gas treatment device in which ACF is fixed to a support or self-supported in a cylindrical shape and longitudinally arranged within the core material.

[0004] Prior art literature

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Application Publication No. 2014-147864 Summary of the Invention

[0007] The problem that the invention aims to solve

[0008] Recovered solvent from adsorbent materials sometimes contains moisture. When reusing recovered solvent in production equipment, dehydration (moisture removal) of the recovered solvent is necessary. As a dehydration method, techniques are known to dehydrate the recovered solvent by contacting it with dehydrating materials such as zeolite. Dehydration is performed by introducing liquid recovered solvent into a dehydration device having a dehydration treatment tank filled with dehydrating material.

[0009] However, a situation arises where, when the dehydration unit is shut down or the organic solvent load in the treated gas is lower than designed, the recovered solvent remains in the dehydration tank for an extended period. In this case, the following problem arises: because water detaches from the dehydration material in the dehydration tank and returns to the recovered solvent, water is discharged during the restart of the dehydration unit to remove insufficiently dehydrated solvent. Another problem is that the organic solvent contained in the dehydration tank evaporates through the piping outlet of the dehydration unit, thereby reducing the amount of organic solvent recovered.

[0010] In this disclosure, the primary objective is to address the aforementioned issues by providing an organic solvent recovery system that can discharge sufficiently dehydrated solvent even during re-operation. Furthermore, the secondary objective is to provide an organic solvent recovery system that can suppress the evaporation of organic solvents contained in the dehydration tank via the piping outlet of the dehydration unit, thereby preventing a decrease in the amount of organic solvent recovered.

[0011] Solution for solving the problem

[0012] The organic solvent recovery system disclosed herein includes a recovery device, a dehydration device, and a return device, and the organic solvent recovery system has the following structure.

[0013] The recovery device includes: an adsorbent material that adsorbs the organic solvent by contacting the gas to be treated containing the organic solvent, and desorbs the organic solvent by contacting water vapor, wherein the organic solvent is sparingly soluble in water and has a specific gravity greater than water; two or more treatment tanks containing the adsorbent material; an adsorption step of supplying the gas to be treated to the treatment tanks to adsorb and remove the organic solvent from the adsorbent material and discharge clean gas; a desorption step of supplying water vapor to the treatment tanks to desorb and recover the solvent from the adsorbent material and discharge desorbed gas; a step of sequentially repeating the adsorption step and the desorption step in the two or more treatment tanks; a condenser that condenses the desorbed gas and discharges the desorbed liquid; and a separator that separates the desorbed liquid into a layer of separated water and a layer of recovered solvent.

[0014] The dehydration device includes: a dehydration material that adsorbs water contained in the recycled solvent by contacting the recycled solvent; one or more dehydration tanks containing the dehydration material; and a discharge mechanism that supplies the recycled solvent separated by the separator to the dehydration tanks and discharges the dehydration solvent obtained by dehydrating the recycled solvent with the dehydration material from the dehydration tanks.

[0015] When the return device returns the recovered solvent from the dehydration tank to the separator, it also feeds the recovered solvent into the layer of the recovered solvent in the separator.

[0016] In the above-described organic solvent recovery system, the return device has a return flow path that, when the dehydration device stops supplying the recovered solvent to the dehydration treatment tank, discharges the recovered solvent out of the dehydration treatment tank and returns the recovered solvent to the separator.

[0017] In the above-described organic solvent recovery system, the dehydration device includes a speed adjustment device for adjusting the rate at which the recovered solvent is fed back to the separator.

[0018] In the above-described organic solvent recovery system, the speed adjustment device uses a portion of the gas being treated or the cleaning gas to pressurize the interior of the dehydration tank, thereby discharging the recovered solvent out of the dehydration tank.

[0019] In the above-mentioned organic solvent recovery system, the organic solvent recovery system has three or more processing tanks, one of the three or more processing tanks performs the desorption process, and the remaining processing tanks are connected in series in multiple stages to perform the adsorption process.

[0020] Invention Effects

[0021] According to this disclosure, an organic solvent recovery system is provided that can discharge sufficiently dehydrated solvent even during restart. Preferably, an organic solvent recovery system is provided that can suppress the evaporation of organic solvents contained in the dehydration treatment tank through the piping outlet of the dehydration unit, thereby suppressing the reduction in the amount of organic solvent recovered. Attached Figure Description

[0022] Figure 1 This is a diagram showing the structure of the organic solvent recovery system of Embodiment 1.

[0023] Figure 2 yes Figure 1 Sectional view along line II-II.

[0024] Figure 3 This is a diagram showing the structure of the organic solvent recovery system of Embodiment 2.

[0025] Figure 4 This is a diagram showing the structure of the organic solvent recovery system of Embodiment 3.

[0026] Figure 5 This is a diagram showing the structure of the organic solvent recovery system of Embodiment 4.

[0027] Figure 6 This is a diagram showing the structure of an organic solvent recovery system according to another embodiment.

[0028] Figure 7 This is a diagram showing the structure of an organic solvent recovery system according to another embodiment. Detailed Implementation

[0029] The organic solvent recovery systems based on the various embodiments of this disclosure will be described below with reference to the accompanying drawings. In the embodiments described below, when referring to numbers, quantities, etc., unless specifically stated otherwise, the scope of the invention is not necessarily limited to those numbers, quantities, etc. Sometimes the same reference numerals are used for the same components or equivalent components, and repeated descriptions are avoided. It is initially intended that the structures in the embodiments be appropriately combined and used.

[0030] The organic solvents used in this disclosure are those that are poorly soluble in water and have a higher specific gravity than water. Specifically, these include 1,2,4-trichlorobenzene, 1,1,1-trichloroethane, trichloroethylene, perchloroethylene, dichloromethane, carbon tetrachloride, chloroform, vinyl chloride, dimethyl carbonate, 1-bromopropane, o-dichlorobenzene, nitrobenzene, 1,2-dichloropropane, epichlorohydrin, monochlorobenzene, 1,2-dichloroethane, 1,1,2-trichloroethane, 1,2-dichloroethylene, 1,1,2-trichloroethane, 1,1,2,2'-tetrachloroethane, pentachloroethane, 1,1-dichloroethylene, methyl bromide, and hydrofluorocarbons such as Freon 11, Freon 12, Freon 225, decafluoropentane, and ethyl nonafluorobutyl ether. Organic solvents other than those listed herein can also be used.

[0031] [Implementation Method 1: Organic Solvent Recovery System 1000]

[0032] Reference Figure 1 and Figure 2 The organic solvent recovery system 1000 of this embodiment will be described. Figure 1 This is a diagram showing the structure of the organic solvent recovery system 1000. Figure 2 yes Figure 1 Sectional view along line II-II.

[0033] The organic solvent recovery system 1000 includes a recovery unit 1, a dehydration unit 2, and a return unit 3. The detailed structure of each of the above units is described below.

[0034] (Recycling Unit 1)

[0035] The recovery device 1 includes a first processing tank 104A and a second processing tank 104B. The first processing tank 104A includes a cylindrical first adsorbent material 105A, and the second processing tank 104B includes a cylindrical second adsorbent material 105B. For the first adsorbent material 105A and the second adsorbent material 105B, the gas to be treated A passes from the outside to the inside to perform an adsorption process, and water vapor passes from the inside to the outside to perform a desorption process. The first adsorbent material 105A and the second adsorbent material 105B use, for example, ACF.

[0036] The first processing tank 104A and the second processing tank 104B are connected to the gas inlet line 103 and the desorption gas line 110. In order to open and close the connection to the gas inlet line 103 and the connection to the desorption gas line 110, a first automatic lower baffle 107A is provided in the first processing tank 104A and a second automatic lower baffle 107B is provided in the second processing tank 104B.

[0037] A first automatic upper baffle 106A for controlling the flow of the gas A to be processed is provided above the first processing tank 104A, and a second automatic upper baffle 106B for controlling the flow of the gas A to be processed is provided above the second processing tank 104B.

[0038] A condenser 111 is connected to the desorption gas line 110. The condenser 111 has a condenser inlet 111B connected to the desorption gas line 110 and a condenser outlet 111C connected to the desorption liquid line 112. A cooling water pipe 111A with a cooling water inlet 111E and a cooling water outlet 111F is housed inside the condenser 111.

[0039] A separator 113 is connected to the desorption line 112, which is connected to the condenser outlet 111C. The separator 113 separates the desorption liquid from the desorption line 112 into a layer of separated water 113A and a layer of recovered solvent 113B. Regarding the separated water 113A, a structure in which water is drained after aeration by the aeration device can be adopted (see [reference]). Figure 6 The organic solvent recovery system 1000D includes an aeration device 800.

[0040] Here, the structure of draining the separated water 113A after aeration in the aeration device refers, for example, to heating the separated water 113A while simultaneously aerating it, thereby vaporizing the organic solvents in the separated water 113A and removing them. By combining it with the organic solvent recovery system 1000 of this embodiment, the organic solvents in the separated water 113A can be removed and purified.

[0041] In the gas A being processed, an organic solvent that is sparingly soluble in water and has a higher specific gravity than water is used. Therefore, inside the separator 113, the recovered solvent 113B is retained in the lower layer, while the separated water 113A is retained in the upper layer. Thus, the recovered solvent 113B is covered by the separated water 113A, suppressing its evaporation outside the system. Inside the separator 113, a recovered solvent level monitoring device 115 is installed to detect the liquid level position of the recovered solvent 113B layer.

[0042] A return gas line 114 is connected to the return gas outlet 111D of the condenser 111 and the gas phase region 113D of the separator 113. The return gas line 114 is introduced into the treated gas line 101. The gas returned from the return gas line 114 to the treated gas line 101 can be introduced in a countercurrent manner relative to the flow direction of the treated gas A.

[0043] A gas blower 102 is provided in the gas line 101. The gas A to be processed, delivered by the gas blower 102, is fed into the first processing tank 104A and the second processing tank 104B via the gas inlet line 103.

[0044] Steam C is supplied to the first processing tank 104A and the second processing tank 104B via steam line 108. The first processing tank 104A is connected to steam line 108, and a first steam on / off valve 109A is installed on steam line 108. The second processing tank 104B is connected to steam line 108, and a second steam on / off valve 109B is installed on steam line 108.

[0045] In the recovery device 1 with the above-described structure, the first automatic upper baffle 106A, the second automatic upper baffle 106B, the first automatic lower baffle 107A, the second automatic lower baffle 107B, the first steam on / off valve 109A, the second steam on / off valve 109B, the condenser 111, the separator 113, the recovered solvent level monitoring device 115, and the blower 102 for the gas being processed are appropriately controlled by a control device (not shown) to achieve the gas processing method described below.

[0046] (Gas processing methods)

[0047] This describes a gas treatment method using a recovery device 1 with the above-described structure. Figure 1 In the process, the first processing tank 104A of the recovery device 1 is subjected to a desorption process, and the second processing tank 104B is subjected to an adsorption process.

[0048] (Adsorption process in the second treatment tank 104B)

[0049] The gas to be treated, including a gas containing an organic solvent, is conveyed from the gas to be treated line 101 to the second processing line 104B, which is in the adsorption process, via the gas to be treated blower 102. The second automatic lower baffle 107B is controlled to open the gas to be treated inlet line 103 and close the desorption gas line 110.

[0050] The second automatic upper baffle 106B is controlled to be in an open state, allowing the flow of the treated gas A in the second adsorbent material 105B to proceed.

[0051] Gas adsorption occurs in the second adsorbent material 105B of the second treatment tank 104B, and the adsorbent is discharged to the outside of the system as clean gas B. The second steam on / off valve 109B of the water vapor line 108 is controlled to be closed.

[0052] (Desorption process in the first treatment tank 104A)

[0053] Instead of supplying the treated gas A to the first processing tank 104A, the first automatic lower baffle 107A controls the process to a state where the treated gas inlet line 103 is closed and the desorption gas line 110 is open. The first automatic lower baffle 107A closes the flow of gas from the outside to the inside of the first adsorbent material 105A. Desorption water vapor C is introduced via water vapor line 108 in a manner that allows flow from the inside to the outside of the first adsorbent material 105A. The first water vapor on / off valve 109A of water vapor line 108 is controlled to be open.

[0054] In the first processing tank 104A, water vapor is ejected, and the organic solvent adsorbed on the first adsorbent material 105A is desorbed from the first adsorbent material 105A. The desorbed gas G, including the desorbed organic solvent, is conveyed to the condenser 111 via the desorbed gas line 110.

[0055] The desorbed gas G and water vapor C obtained from desorption are condensed in condenser 111. The desorbed liquid H, containing a high concentration of organic solvent, is conveyed to separator 113 via desorbed liquid line 112. In separator 113, the desorbed liquid H is separated into a layer of separated water 113A and a layer of recovered solvent 113B. Inside separator 113, as described above, the recovered solvent 113B is retained in the lower layer, and the separated water 113A is retained in the upper layer.

[0056] The return gas J retained in the condenser 111 and separator 113 is compressed by the desorbed gas G and introduced into the treated gas line 101 via the return gas line 114, where it mixes with the treated gas A. The treated gas A and the return gas J introduced from the treated gas line 101 are then conveyed to the second processing tank 104B.

[0057] The above process is repeated to feed the recovered solvent 113B into the dehydration unit 2 from the recovered solvent line 210, which is connected to the layer of the recovered solvent 113B in the separator 113.

[0058] After a certain period of time, the adsorption and desorption processes switch, with the first treatment tank 104A becoming the adsorption process and the second treatment tank 104B becoming the desorption process. In this way, through the continuous processing of alternating adsorption and desorption processes, the recovery device 1 continuously recovers the solvent 113B.

[0059] (Dehydration device 2)

[0060] Next, in dehydration device 2, dehydration treatment is performed on the recovered solvent 113B recovered by the aforementioned recovery device 1. The structure of dehydration device 2 is described below. Dehydration device 2 includes: a dehydrating material 202, which adsorbs the water contained in the recovered solvent 113B by contacting it with the recovered solvent 113B separated by separator 113; and a dehydration treatment tank 203, which holds the dehydrating material 202. The dehydrating material 202 may be, for example, zeolite. Alternatively, activated alumina, ion exchange resin, activated carbon, etc., may also be used.

[0061] The separator 113 and the dehydration tank 203 are connected by a solvent recovery line 210. One end of the solvent recovery line 210 is connected to the layer of recovered solvent 113B separated by the separator 113. The other end of the solvent recovery line 210 is connected to the lower end of the dehydration tank 203.

[0062] A pump 201 is installed along the solvent recovery line 210. Pump 201 delivers the recovered solvent 113B into the dehydration treatment tank 203. A check valve 205 is installed on the downstream side of the solvent recovery line 210 of pump 201. The check valve 205 prevents the backflow of the recovered solvent 113B from the dehydration treatment tank 203 towards the pump 201.

[0063] A dehydration solvent discharge line 113C is provided at the upper part of the dehydration treatment tank 203. A dehydration solvent valve 401 is provided at the dehydration solvent discharge line 113C. Furthermore, a flow regulating valve 402 capable of introducing a specified gas is connected to the dehydration solvent valve 401. The pump 201, the dehydration solvent valve 401, and the flow regulating valve 402 are appropriately controlled by a control device (not shown) to achieve the dehydration treatment described below.

[0064] (Dehydration treatment)

[0065] The recovered solvent 113B, fed into the dehydration treatment tank 203 from the lower side by the operation of pump 201, is dehydrated by contacting the dehydration material 202 and is discharged out of the system as dehydration solvent E from the dehydration solvent discharge line 113C. The discharge mechanism for discharging the dehydration solvent E from the dehydration treatment tank 203 consists of at least the recovered solvent line 210, pump 201, and dehydration solvent discharge line 113C.

[0066] (Loopback device 3)

[0067] If the dehydration device 2 is stopped, or if the organic solvent load in the treated gas is less than designed, the recovered solvent 1 13B may remain in the dehydration tank 203 for an extended period. In this case, as water detaches from the dehydration material 202 in the dehydration tank 203 and returns to the recovered solvent 1 13B, during the restart of the dehydration device 2, water may be discharged to remove insufficiently removed dehydrating solvent E. Furthermore, the organic solvent contained in the dehydration tank 203 may evaporate through the piping outlet of the dehydration device 2, potentially reducing the amount of organic solvent recovered.

[0068] Therefore, when the dehydration unit 2 stops or the organic solvent load in the gas being processed is less than designed, the return device 3 operates to return the recovered solvent 113B in the dehydration treatment tank 203 to the separator 113. Specifically, the return device 3 has a structure that returns the recovered solvent 113B to the separator 113 in layers.

[0069] Reference Figure 2 In this embodiment, a partition 116 is provided inside the separator 113. The partition 116 forms an independent space with its upper and lower ends open inside the separator 113. The lower end of the partition 116 reaches the layer of recovered solvent 113B. The upper end of the partition 116 is open to the gas phase region 113D. When operating the organic solvent recovery system 1000, a predetermined amount of recovered solvent 113B needs to be pre-stored inside the separator 113 until it exceeds the height of the lower end of the partition 116.

[0070] Refer again Figure 1 Downstream of the check valve 205 of the solvent recovery line 210, which connects to the dehydration treatment tank 203, a return line 301 branching off from the solvent recovery line 210 is provided. This return line 301 operates as follows: when the dehydration unit 2 stops supplying the solvent recovery 113B, etc., to the dehydration treatment tank 203, the solvent recovery 113B is discharged outside the dehydration treatment tank 203, and the solvent recovery 113B is returned to the separator 113. An on / off valve 302 is provided on the return line 301.

[0071] The on / off valve 302, the dehydration solvent valve 401, and the flow regulating valve 402 are appropriately controlled by a control device (not shown) to achieve the following process of returning the recovered solvent 113B in the dehydration treatment tank 203 to the separator 113.

[0072] (Recycled solvent 113B)

[0073] With the recovered solvent 113B discharged out of the dehydration treatment tank 203, and with the on / off valve 302 open and the dehydration solvent valve 401 closed, a specified gas is introduced through the flow regulating valve 402. This pressurizes the internal pressure of the dehydration treatment tank 203, causing the recovered solvent 113B remaining inside the dehydration treatment tank 203 to be returned to the separator 113.

[0074] Here, an external gas can be used as the specified gas, but it is preferable to use, for example, the gas to be treated A or the cleaning gas B. Furthermore, by using the flow regulating valve 402 to control the amount and speed of the gas fed in, it is possible to prevent the gas from being introduced all at once and to allow the gas to be introduced gradually. This allows for adjustment of the amount and speed of the recovered solvent 113B fed back to the separator 113. As a result, the organic solvent contained in the gas to be treated A can be recovered efficiently. In particular, this is very economical when organic solvents are expensive.

[0075] The recovered solvent 113B returned to separator 113 is fed into a space within separator 113 separated by partition 116. Thus, the recovered solvent 113B returned to separator 113 directly returns to the layer of recovered solvent 113B within separator 113. Consequently, the recovered solvent 113B will not mix with the separated water 113A again.

[0076] Thus, according to the organic solvent recovery system 1000 in this embodiment, in the event that the dehydration device 2 stops or the organic solvent load in the gas A being processed is less than designed, in order to prevent the recovered solvent 113B from remaining in the dehydration treatment tank 203 for a long time, the operation control is performed as described above to return the recovered solvent 113B in the dehydration treatment tank 203 to the separator 113.

[0077] Therefore, even if the dehydration unit 2 is restarted via the organic solvent recovery system 1000, the dehydration solvent E, which has been sufficiently dehydrated, can be discharged outside the system. Furthermore, the evaporation of organic solvents contained in the dehydration treatment tank 203 through the piping outlet of the dehydration unit 2 can be suppressed. Thus, as a whole, the organic solvent recovery system 1000 can be expected to achieve improved organic solvent recovery.

[0078] Even when the dehydration unit 2 is stopped (pump 201 is stopped), completely closing the inlet and outlet valves of the dehydration treatment tank 203 can prevent the recovered solvent 113B from remaining in the dehydration treatment tank 203 for an extended period. However, the internal pressure may rise when some of the recovered solvent 113B evaporates in the dehydration treatment tank 203 due to external gas temperature or other factors. Furthermore, if the recovered solvent 113B is continuously kept in the dehydration treatment tank 203 for an extended period, there is a possibility that the water obtained from dehydration may separate from the dehydration material 202. Therefore, it is preferable to perform operation control that returns the recovered solvent 113B from the dehydration treatment tank 203 to the separator 113, as shown in the above embodiment.

[0079] It should be noted that a structure including a temperature control mechanism can also be adopted, which adjusts the temperature so that the recovered solvent 113B contained in any one or more of the separator 113, dehydration device 2, return device 3, and dehydration treatment tank 203 is at a specified temperature.

[0080] [Implementation Method 2: Organic Solvent Recovery System 1000A]

[0081] Reference Figure 3 The organic solvent recovery system 1000A of this embodiment will be described. Figure 3 This is a diagram showing the structure of the 1000A organic solvent recovery system.

[0082] The basic structure of the organic solvent recovery system 1000A is the same as that of the organic solvent recovery system 1000 described in Embodiment 1 above. The difference lies in the structure of the dehydration device 2. In the dehydration device 2 of this embodiment, the solvent recovery line 210 is connected to the upper side of the dehydration treatment tank 203, and the solvent discharge line 113C is connected to the lower side of the dehydration treatment tank 203. Therefore, the solvent recovery line 113B flows from top to bottom.

[0083] This structure can also achieve the same effect as the organic solvent recovery system 1000 in Embodiment 1 above.

[0084] [Implementation Method 3: Organic Solvent Recovery System 1000B]

[0085] Reference Figure 4 The organic solvent recovery system 1000B of this embodiment will be described. Figure 4 This is a diagram showing the structure of the organic solvent recovery system 1000B.

[0086] The basic structure of the organic solvent recovery system 1000B is the same as that of the organic solvent recovery system 1000 described in Embodiment 1 above. The difference lies in the structure of the separator 113. In this embodiment, the separator 113 does not have a partition 116, and the return line 301 is directly connected to the layer of recovered solvent 113B in the separator 113.

[0087] This structure can also achieve the same effect as the organic solvent recovery system 1000 in Embodiment 1 above.

[0088] [Implementation Method 4: Organic Solvent Recovery System 1000C]

[0089] Reference Figure 5 The organic solvent recovery system 1000C of this embodiment will be described. Figure 5 This is a diagram showing the structure of the organic solvent recovery system 1000C.

[0090] The basic structure of the organic solvent recovery system 1000C is the same as that of the organic solvent recovery system 1000 described in Embodiment 1 above. The difference is that, in the structure of the dehydration device 2, a first dehydration treatment tank 203A and a second dehydration treatment tank 203B are provided as dehydration treatment tanks. While the dehydrated material 202 in one treatment tank is being processed, the other dehydration treatment tank is operated, thereby enabling the dehydration device 2 to operate continuously.

[0091] This structure can also achieve the same effect as the organic solvent recovery system 1000 in Embodiment 1 above.

[0092] It should be considered that all aspects of the disclosed embodiments are illustrative rather than restrictive. The scope of the present invention is defined not by the foregoing description but by the technical solutions, and is intended to include all modifications with the same meaning and scope as the technical solutions.

[0093] In the above-disclosed recycling apparatus 1, the recycling of organic solvents is described by using a first processing tank 104A and a second processing tank 104B as processing tanks to alternate between adsorption and desorption processes, but it is not limited to recycling using these two processing tanks.

[0094] For example Figure 7 As shown, as a variation of the organic solvent recovery system 1000 of Embodiment 1, the organic solvent recovery system 1000E disclosed in Japanese Patent Application Publication No. 2014-147863 can also be used. This system employs three processing tanks: a first processing tank 104A, a second processing tank 104B, and a third processing tank 104C. A desorption process is performed in one of these three processing tanks, while the remaining processing tanks are connected in series in multiple stages to perform an adsorption process. Figure 7 The diagrams of the dehydration device 2, the return device 3, the condenser 111, and the separator 113 are omitted. It should be noted that there can be more than three processing tanks. This further improves the recovery efficiency of organic solvents.

[0095] Explanation of reference numerals in the attached figures

[0096] 1. Recovery device; 2. Dehydration device; 3. Return device; 101. Processed gas line; 102. Processed gas blower; 103. Processed gas inlet line; 104A. First processing tank; 104B. Second processing tank; 104C. Third processing tank; 105A. First adsorbent material; 105B. Second adsorbent material; 105C. Third adsorbent material; 106A. First automatic upper baffle; 106B. Second automatic upper baffle; 106C. Third automatic upper baffle; 107A. First automatic lower baffle; 107B. Second automatic lower baffle; 107C. Third automatic lower baffle; 108. Steam line; 109A. First steam on / off valve; 109B. Second steam on / off valve; 110. Desorbed gas line; 111. Condenser; 111A. Cooling water piping; 111B. Condenser inlet; 111. 1C Condenser Outlet, 111D Gas Outlet, 111E Cooling Water Inlet, 111F Cooling Water Outlet, 112 Desorption Line, 113 Separator, 113A Separated Water, 1 13B Recovered Solvent, 113C Dehydration Solvent Discharge Line, 113D Gas Phase Zone, 114 Return Gas Line, 115 Recovered Solvent Liquid Level Monitoring Device, 116 Baffle, 201 Pump, 202 Dehydration Material, 203 Dehydration Treatment Tank, 203A First Dehydration Treatment Tank, 203B Second Dehydration Treatment Tank, 205 Check Valve, 210 Recovered Solvent Line, 301 Return Line, 302 On / Off Valve, 401 Dehydration Solvent Valve, 402 Flow Adjustment Valve, 800 Aeration Device, 1000, 1000A, 1000B, 1000C Organic Solvent Recovery System, A Treated Gas, B Clean Gas, C Water Vapor, E Dehydration Solvent, G Desorbed Gas, H Desorbed Liquid, J Return Gas.

Claims

1. An organic solvent recovery system, The organic solvent recovery system includes a recovery device, a dehydration device, and a return device, wherein... The recycling device includes: An adsorbent material that adsorbs an organic solvent by contacting a gas to be treated containing an organic solvent, and desorbs the organic solvent by contacting water vapor, wherein the organic solvent is poorly soluble in water and has a higher specific gravity than water; Two or more processing tanks containing the adsorbent material; An adsorption process in which the gas to be treated is supplied to the treatment tank and the organic solvent is adsorbed and removed by the adsorption material, and a clean gas is discharged. A desorption process in which water vapor is supplied to the treatment tank to desorb and recover the solvent from the adsorbent material and discharge the desorbed gas; The adsorption process and the desorption process are repeated sequentially in two or more of the aforementioned treatment tanks. A condenser that condenses the desorbed gas and discharges the desorbed liquid; and A separator that separates the desorbed liquid into a layer of separated water and a layer of recovered solvent. The dehydration device includes: A dehydrating material that adsorbs the water contained in the recycled solvent by contacting the recycled solvent; One or more dehydration tanks containing the aforementioned dehydration material; and The discharge mechanism supplies the recovered solvent separated by the separator to the dehydration treatment tank, and discharges the dehydrated solvent obtained by dehydration from the recovered solvent through the dehydration material from the dehydration treatment tank. When the return device returns the recovered solvent from the dehydration tank to the separator, it also feeds the recovered solvent into the layer of the recovered solvent in the separator. The return device has a return flow path that, when the dehydration device stops supplying the recovered solvent to the dehydration treatment tank, discharges the recovered solvent out of the dehydration treatment tank and returns the recovered solvent to the separator.

2. The organic solvent recovery system according to claim 1, wherein, The dehydration device includes a speed adjustment device for adjusting the rate at which the recovered solvent is fed back to the separator.

3. The organic solvent recovery system according to claim 2, wherein, The speed adjustment device uses a portion of the gas being treated or the cleaning gas to pressurize the interior of the dehydration tank, thereby discharging the recovered solvent out of the dehydration tank.

4. The organic solvent recovery system according to any one of claims 1 to 3, wherein, The organic solvent recovery system has three or more processing tanks, one of which performs the desorption process, and the remaining processing tanks are connected in series in multiple stages to perform the adsorption process.

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