JP2013072611A - Voc processing system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technology capable of separating and collecting resin compositions contained in a solvent waste from the solvent waste in a VOC processing system for combustion treatment of volatile organic compounds contained in the solvent waste.SOLUTION: The VOC processing system includes a separating and collecting device for resin compositions in which a condensing and separating medium for condensing a nonvolatile resin composition contained in the solvent waste containing the organic solvent is added to the solvent waste and the resin composition is separated and collected from the solvent waste and a VOC processing device to which a residual solvent waste after resin composition collection from the solvent waste by the separating and collecting device for resin compositions is supplied and in which the volatile organic compound contained in the supplied residual solvent waste is processed by combustion treatment.

Description

  The present invention relates to a VOC processing system for processing a volatile organic compound contained in a solvent waste liquid.

  Organic solvents are widely used as raw materials for producing various uses, for example, adhesives, pressure-sensitive adhesives, paints and the like. In these applications, facilities that use organic solvents contain not only waste gases containing volatile organic compounds (hereinafter sometimes abbreviated as “VOC” or “VOC gas”) but also organic solvents. Volatile organic compounds (VOC) are also discharged as waste liquid (hereinafter referred to as “solvent waste liquid”). Volatile organic compounds (VOC) are one of the causes of generating suspended particulate matter, photochemical oxidants, and the like that are feared to affect human bodies. In order to suppress the emission of volatile organic compounds (VOC), measures to reduce the total amount of organic solvent emissions and reduce the use of voluntary organic solvents for VOC emissions and scattering from facilities such as factories Measures such as promotion of approach are taken.

  There is a process for producing various resin compositions such as adhesives, pressure-sensitive adhesives, paints and the like using an organic solvent. Further, there is a step of applying and drying these various resin compositions on a substrate. Various methods can be adopted as a method for treating VOCs generated in these steps and contained in the solvent waste liquid. For example, there is a method in which this solvent waste liquid is recovered as a purified liquid solvent by evaporating volatile components by heating distillation and then liquefied by cooling and reused. Alternatively, there are a method in which the VOC gas that evaporates by heating the solvent waste liquid is directly burned by the VOC processing device, a method in which the VOC processing device is mixed with another combustible gas, and is burned by the VOC processing device.

  In this regard, for example, Patent Document 1 discloses waste gas and solvent waste liquid in which VOC contained in waste gas discharged from equipment using an organic solvent is supplied to a waste gas treatment apparatus as a fuel for combustion treatment. Discloses a method for burning VOC. More specifically, in Patent Document 1, exhaust gas generated by combustion treatment from a waste gas treatment apparatus is blown into a solvent waste liquid, and VOC contained in the solvent waste liquid is vaporized to evaporate gaseous VOC from the solvent waste liquid. It is disclosed. Furthermore, Patent Document 1 discloses a technique for supplying a vaporized VOC to a waste gas treatment apparatus as a gas and performing a combustion treatment. Moreover, the apparatus and method which process the waste gas and solvent waste liquid containing an organic solvent are described in patent documents 2-5, for example.

JP 2010-007973 A JP 2004-037038 A JP 2004-036492 A JP 2004-184003 A JP 2004-089884 A

By the way, from the viewpoint of effective utilization of resources, it is desirable to separate and recover the resin composition contained in the solvent waste liquid and effectively utilize it as a recycled resource. In the prior art, the residue after vaporizing VOC from the solvent waste liquid containing the resin composition at the time of treatment of the solvent waste liquid must be incinerated as it is as a solvent waste liquid containing the resin composition and moisture. There was a problem that the processing cost of the solvent waste liquid increased.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a VOC treatment system for combustion treatment of a volatile organic compound contained in a solvent waste liquid, and a resin composition contained in the solvent waste liquid from the solvent waste liquid. The object is to provide a technique capable of separation and recovery.

  In order to solve the above problems, the present invention employs the following means. That is, the VOC treatment system according to the present invention adds a flocculent separation agent to the solvent waste liquid to agglomerate the non-volatile resin composition contained in the solvent waste liquid containing the organic solvent, and the resin composition from the solvent waste liquid. Residual solvent waste liquid after the resin composition is recovered from the solvent waste liquid by the resin composition separation and recovery apparatus for separating and recovering the product and the resin composition separation and recovery apparatus is supplied. And a VOC treatment device for subjecting the volatile organic compound contained in the remaining solvent waste liquid to a combustion treatment.

  According to the VOC processing system having the above-described configuration, since the resin composition separation and recovery device is arranged at the front stage of the VOC processing apparatus, the resin composition contained in the solvent waste liquid before the solvent waste liquid is transferred to the VOC processing apparatus. The product can be separated and recovered from the solvent waste liquid. The aggregating / separating agent is preferably one or more compounds selected from the group consisting of an aqueous alcohol solution, a polyether, a paraffinic hydrocarbon having 6 or more carbon atoms, and a polymer electrolyte.

  The “volatile organic compound contained in the solvent waste liquid” that is burned by the VOC treatment device means, for example, the volatile content contained in the solvent waste liquid when the solvent waste liquid is discharged from a facility using an organic solvent. Any organic compound may be used, and the volatile organic compound may be liquid or gas during the combustion treatment. For example, the VOC treatment device may be a device that supplies gaseous VOC gas as fuel from a waste liquid treatment device that vaporizes a volatile organic compound contained in the solvent waste liquid. Alternatively, the VOC treatment device may be a device that burns a liquid volatile organic compound contained in the solvent waste liquid.

  Further, the resin composition separation and recovery device includes a solvent waste liquid storage tank in which the solvent waste liquid is stored, a flocculant separation agent storage tank in which the flocculant separation agent is stored, and the solvent waste liquid and the flocculant separation from the solvent waste liquid storage tank. An agitation / mixing tank to which the flocculating / separating agent is supplied from an agent storage tank, a mixing unit for agitating and mixing the solvent waste liquid and the flocculating / separating agent by an agitation unit provided inside the agitation / mixing tank; And a filtering means for filtering the resin composition aggregated by stirring and mixing the waste liquid and the aggregating / separating agent.

  The VOC treatment system is disposed between the resin composition separation and recovery device and the VOC treatment device, and after the resin composition is collected from the solvent waste liquid by the resin composition separation and recovery device. Further, a separation / recovery device for aggregating / separating agent that separates and recovers the aggregating / separating agent from the remaining solvent waste liquid (hereinafter referred to as “resin liquid after removal of the resin composition”) may be further provided. According to this configuration, the resin composition-removed waste liquid is not directly transferred to the VOC treatment apparatus, and the aggregation / separation agent can be separated and recovered from the resin composition-removed waste liquid by the aggregation / separation agent separation / recovery apparatus.

The separation / recovery device for aggregating / separating agent includes a specific gravity difference separation tank for separating the aggregating / separating agent from the residual solvent waste liquid (resin liquid after removal of the resin composition) using a specific gravity difference, and the specific gravity difference separation. A distillation purification apparatus for purifying the flocculating / separating agent by distilling the flocculating / separating agent separated from the solvent waste liquid by a tank. According to this configuration, in the specific gravity difference separation tank, first, the resin composition-removed waste liquid and the aggregating / separating agent are separated using the specific gravity difference. The waste liquid after the removal of the coagulation / separation agent after the coagulation / separation agent is removed, obtained in the specific gravity difference separation tank, is transferred to a VOC treatment device at the subsequent stage, and the volatile organic compound is burned. On the other hand, the aggregating / separating agent separated and recovered from the resin composition-removed waste liquid is distilled in a distillation purification apparatus to purify the aggregating / separating agent. According to this separation / recovery device for aggregating / separating agent, the aggregating / separating agent purified by the distillation purification device can be efficiently recycled.

  The means for solving the problems in the present invention can be combined as much as possible.

  ADVANTAGE OF THE INVENTION According to this invention, in the VOC processing system which carries out the combustion process of the volatile organic compound contained in a solvent waste liquid, it is possible to isolate | separate and collect the resin composition contained in a solvent waste liquid.

It is the schematic block diagram which showed an example of the VOC processing apparatus relevant to this invention. It is a schematic block diagram of the separation-and-recovery apparatus for resin compositions concerning this invention. It is a schematic block diagram of the separation / recovery device for a flocculent separation agent according to the present invention. It is the elements on larger scale for demonstrating the detailed structure of the isolation | separation collection | recovery apparatus for flocculent separation agents concerning this invention. In Example 1, it is a graph showing the relationship between the quantity (weight part) of the methanol aqueous solution added with respect to 100 weight part of solvent waste liquid, and the density | concentration of the resin composition after removing the aggregated resin composition. . In Example 1, it is a graph showing the relationship between the quantity (weight part) of the methanol aqueous solution added with respect to 100 weight part of solvent waste liquid, and the recovery rate of a resin composition. In Example 2, it is a graph showing the relationship between the quantity (weight part) of the methanol aqueous solution added with respect to 100 weight part of solvent waste liquid, and the density | concentration of the resin composition after removing the aggregated resin composition. . In Example 2, it is a graph showing the relationship between the quantity (weight part) of methanol aqueous solution added with respect to 100 weight part of solvent waste liquid, and the recovery rate of a resin composition.

  Hereinafter, a VOC processing system according to the present invention will be described with reference to the drawings. Hereinafter, a VOC treatment system including a resin composition separation / recovery device, a flocculant separation agent separation / recovery device, and a VOC treatment device will be described as an example. However, the dimensions, materials, shapes, relative positions, and the like of the components described are not intended to limit the scope of the present invention only, unless otherwise specified, and are merely examples. Absent.

  FIG. 1 is a schematic configuration diagram of a VOC processing apparatus that performs combustion processing of a volatile organic compound (VOC). The VOC treatment apparatus 1 includes a VOC gas discharged from a volatile organic compound (VOC) generation facility (hereinafter simply referred to as “VOC generation facility”) 2 using an organic solvent, and a solvent containing the organic solvent. It is a device for burning VOC gas contained in waste liquid.

  The VOC processing device 1 includes a waste gas processing device 4 and a waste liquid processing device 5. The waste gas treatment device 4 is a device that performs combustion treatment of VOC gas. The waste liquid treatment apparatus 5 is an apparatus that vaporizes VOC contained in the solvent waste liquid discharged from the VOC generation facility 2 and supplies it to the waste gas treatment apparatus 4 as fuel. Examples of the waste gas treatment device 4 include a boiler, a gas turbine, a heat storage deodorization device (RTO), a reciprocating engine, and the like, and can receive a VOC gas to burn the VOC in the gas.

  By burning the VOC gas by the waste gas treatment device 4, the VOC gas is decomposed into water and carbon dioxide that are allowed to be released into the atmosphere. The type of VOC gas to be treated by the waste gas treatment device 4 is not particularly limited as long as it is flammable, but general examples include hydrocarbon solvents such as toluene, xylene, and normal hexane, ethyl acetate, Ester solvents such as butyl acetate and methoxybutyl acetate, ketone solvents such as acetone, methyl ethyl ketone (MEK) and methyl isobutyl ketone, alcohol solvents such as methanol, ethanol and propanol, methyl cellosolve, ethyl cellosolve, ethylene glycol dimethyl ether And vapors of various organic solvents such as alcohol ether solvents.

  The VOC treatment system separates and recovers the resin composition contained in the solvent waste liquid discharged from the VOC generation equipment 2 in addition to the VOC treatment apparatus 1, and separates and recovers the resin composition for the resin composition 6, and aggregates from the resin composition removed waste liquid A separation / recovery device 8 for aggregating / separating agent that separates and recovers the separation agent, a control device 100 that controls the entire operation of the VOC processing device 1, and the like are provided. The control device 100 may be a general-purpose computer including a processor, a memory, an input device such as a keyboard and a mouse, a display, a portable recording medium driving device, an interface, and the like. The control device 100 is electrically connected to various measuring instruments, fans, pumps, and the like, which will be described later, through electrical wiring. Detection signals from the measuring instruments are input from the interface, and control signals to the fans, pumps, etc. Are output to these from the interface.

  The VOC generation facility 2 and the waste gas treatment device 4 are connected by a waste gas transfer pipe 41 that transfers VOC gas. As will be described later, the VOC gas recovered from the solvent waste liquid is supplied to the waste gas treatment apparatus 4 from the waste liquid treatment apparatus 5 as fuel. Therefore, the waste gas treatment apparatus 4 can perform not only the VOC contained in the waste gas transferred from the VOC generation facility 2 but also the VOC supplied from the waste liquid treatment apparatus 5.

  The waste liquid treatment apparatus 5 is supplied from a solvent waste liquid storage container 51 in which a solvent waste liquid (as will be described later, this solvent waste liquid corresponds to a waste liquid after removal of the coagulation / separation agent) is stored. It is generated by VOC vaporization tank (hereinafter simply referred to as “vaporization tank”) 52 for vaporizing VOC contained in the solvent waste liquid by blowing gas into the solvent waste liquid, and VOC combustion treatment in the waste gas treatment apparatus 4. An exhaust gas supply pipe 53 for supplying a part of the exhaust gas to the vaporization tank 52 and a gas VOC separated from the solvent waste liquid in the vaporization tank 52 are supplied to the waste gas treatment device 4 as a gas. VOC gas delivery pipe 54, etc. are provided.

  The solvent waste liquid storage container 51 and the vaporization tank 52 are connected by a solvent waste liquid transfer pipe 55 that transfers the solvent waste liquid from the solvent waste liquid storage container 51 to the vaporization tank 52. A pump 56 is installed in the solvent waste liquid transfer pipe 55. Further, the vaporization tank 52 is provided with a first liquid level meter 57 for detecting the level (liquid level) of the stored solvent waste liquid. The control device 100 controls the operation of the pump 56 based on the detection result of the first liquid level meter 57. When the liquid level of the solvent waste liquid becomes lower than the lower reference level B, the pump 56 is operated and the solvent waste liquid is transferred from the solvent waste liquid storage container 51 to the vaporization tank 52. When the liquid level in the vaporization tank 52 reaches the upper reference level A of the first liquid level gauge 57, the solvent waste liquid is not transferred to the vaporization tank 52 by stopping the pump 56.

The exhaust gas outlet of the exhaust gas supply pipe 53 is provided at a position lower than the lower reference level B of the first liquid level gauge 57, and is always below the level of the solvent waste liquid during operation of the VOC treatment device 1. It is located to become. The exhaust gas supply pipe 53 is provided with a large number of outlets for blowing exhaust gas from the waste gas treatment device 4 into the solvent waste liquid in the vaporization tank 52, for example. This can improve the gas replacement efficiency of VOC dissolved in the solvent waste liquid. Further, for example, the VOC concentration of the VOC gas supplied to the waste gas treatment device 4 may be monitored, and the bubbling air volume of the exhaust gas supply pipe 53 may be controlled according to the VOC concentration.

  Since the exhaust gas generated in the waste gas treatment device 4 is subjected to combustion treatment, it does not contain VOC and has a high temperature. When exhaust gas discharged from the waste gas treatment device 4 is blown into the solvent waste liquid from the exhaust gas supply pipe 53, the partial pressure of VOC contained in the exhaust gas (corresponding to substantially 0 because it does not contain VOC). The VOC in the solvent waste liquid is vaporized into the exhaust gas bubbles due to the difference between the VOC saturation vapor pressure at the exhaust gas temperature. Therefore, the higher the temperature of the exhaust gas, the more efficiently VOC is vaporized. However, it is not necessary to make the temperature of the exhaust gas extremely high, and a temperature lower than the boiling point of VOC contained in the solvent waste liquid is sufficient.

  One end of a VOC gas delivery pipe 54 is connected to the vaporization tank 52. The vaporized VOC is sent to the outside through the VOC gas delivery pipe 54 from the vaporization tank 52 together with the exhaust gas. The other end side of the VOC gas delivery pipe 54 merges with the waste gas transfer pipe 41. A fan 59 is installed in the middle of the VOC gas delivery pipe 54. By operating the fan 59, VOC is sucked from the vaporization tank 52. It is not necessary to use 100% of the exhaust gas discharged from the waste gas treatment device 4 as the gas supplied to the exhaust gas supply pipe 53. For example, in order to lower the temperature of the supplied exhaust gas, other gases ( For example, air) may be mixed. The gas to be mixed can be arbitrarily selected.

  For example, in the VOC processing apparatus 1 shown in FIG. 1, the bypass pipe 45 is branched from the waste gas transfer pipe 41, and the distal end side of the bypass pipe 45 is connected to the vaporization tank 52. A fan 46 is installed in the middle of the bypass pipe 45. By operating the fan 46, at least a part of the waste gas from the VOC generation facility 2 can be introduced into the vaporization tank 52. As described above, by introducing the waste gas from the VOC generation facility 2 into the vaporization tank 52, it is possible to assist the delivery of the VOC contained in the solvent waste liquid from the vaporization tank 52.

  The VOC gas delivery pipe 54 measures the VOC concentration in the VOC gas flowing through the exhaust gas transfer pipe 41 on the downstream side (waste gas treatment device 4 side) from the outlet where it joins the waste gas transfer pipe 41. A total 42 is provided. The control device 100 monitors the total amount of VOC supplied to the waste gas treatment device 4 based on the detection value of the gas concentration meter 42.

  The exhaust gas supply pipe 53 is provided with a fan 43 that sends exhaust gas from the waste gas treatment device 4 toward the vaporization tank 52. The fan 43 is controlled based on the detection value of the gas concentration meter 42. When the control device 100 detects that the VOC concentration detected by the gas concentration meter 42 is lower than the set concentration, the control device 100 operates the fan 43 installed in the exhaust gas supply pipe 53 to start from the waste gas processing device 4. The exhaust gas is supplied to the vaporization tank 52. Thereby, the supply amount of the exhaust gas to the vaporization tank 52 is increased, and the vaporization of VOC is promoted. On the other hand, when the control device 100 detects that the VOC concentration detected by the gas concentration meter 42 has risen above the set concentration, the control device 100 stops the supply of the exhaust gas to the exhaust gas supply pipe 53, or the exhaust gas VOC vaporization is suppressed by reducing the supply amount of VOC.

In the VOC generation facility 2 that uses an organic solvent (for example, a laminating machine for packaging materials), many organic solvents are used as a diluting solvent for adhesives and pressure-sensitive adhesives (hereinafter referred to as adhesives). Organic solvents are often used for cleaning the dirt of manufacturing equipment. In the manufacturing process of various products performed using this adhesive or the like, the surplus for each production lot of raw materials or the parting product exceeding the expiration date is discarded as a solvent waste liquid. Examples of the resin composition contained in the solvent waste liquid to be disposed of include, for example, polymers polymerized using ether-based, ester-based, urethane-based, acrylic-based, and epoxy-based resin monomers, and those resin monomers and functional groups. Examples thereof include a copolymer copolymerized with a resin monomer having a group. Examples of the product name of the adhesive for laminating include Dick Dry (manufactured by DIC Graphics Co., Ltd.) having an ester-based or ether-based lineup.

  As described above, the VOC gas discharged from the VOC generation facility 2 using the organic solvent is sent to the waste gas treatment device 4 through the waste gas transfer pipe 41, and the VOC contained in the exhaust gas is burned. Further, the solvent waste liquid discharged from the VOC generation facility 2 is sent to the solvent waste liquid storage container 51 of the waste liquid treatment apparatus 5 after the resin composition is removed in the resin composition separation and recovery apparatus 6 to be described later. Stored.

  Then, exhaust gas generated by VOC combustion processing in the waste gas treatment device 4 is blown from the exhaust gas supply pipe 53 into the solvent waste liquid sent from the solvent waste liquid storage container 51 to the vaporization tank 52, so that VOC vaporizes. In this way, the VOC separated from the solvent waste liquid is supplied to the waste gas treatment device 4 in a gaseous state via the VOC gas delivery pipe 54 and the waste gas transfer pipe 41. And in the waste gas processing apparatus 4, a combustion process is performed by using VOC supplied in the gaseous state as fuel. As described above, the VOC generated in the VOC generation facility 2 is decomposed into water, carbon dioxide and the like through the combustion treatment by the waste gas treatment device 4 and rendered harmless.

  By the way, most of the solvent waste liquid discharged from the VOC generation facility 2 using an organic solvent contains a resin composition composed of a resin polymer and the like, and is contained in the solvent waste liquid from the viewpoint of effective use of resources. It is desirable to recycle the resin composition. Further, since the resin composition exhibits non-volatility, it remains in the vaporization tank 52 without being vaporized. As a result, the resin composition precipitates and accumulates inside the vaporization tank 52 due to slurrying or the like, causing the vaporization tank 52 to become dirty. Further, if the solvent waste liquid supplied to the vaporization tank 52 contains a large amount of the resin composition, the frequency of inspecting and cleaning the inside of the vaporization tank 52 is increased, which may cause the generation efficiency of the VOC gas to deteriorate. . Therefore, in the VOC treatment apparatus 1, the resin composition separation / recovery device 6 is disposed in front of the waste liquid treatment apparatus 5, and the resin composition is previously removed from the solvent waste liquid, and then transferred to the waste liquid treatment apparatus 5. I did it.

  FIG. 2 is a schematic configuration diagram of the resin composition separation and recovery device 6. FIG. 3 is a schematic configuration diagram of the separation / recovery device 8 for aggregating / separating agent. The resin composition separation and recovery device 6 is a device that is provided in the front stage of the waste liquid treatment device 5 and recovers the resin composition contained in the solvent waste liquid discharged from the VOC generation facility 2. The resin composition separation and recovery device 6 includes a solvent waste liquid storage tank 61, an aggregating / separating agent storage tank 62, a stirring and mixing tank 63, a filtration tank 64, and connection pipes for connecting the tanks.

  The solvent waste liquid storage tank 61 stores the untreated solvent waste liquid discharged from the VOC generation facility 2. Further, the flocculating / separating agent storage tank 62 stores a flocculating / separating agent that causes the resin composition contained in the solvent waste liquid to flocculate. The solvent waste liquid storage tank 61 and the flocculating / separating agent storage tank 62 are connected to the stirring and mixing tank 63 via connection pipes 65 and 66, respectively.

  Inside the stirring and mixing tank 63, a stirrer 67 having a stirring blade that is rotationally driven by a drive motor (not shown) is provided. A connecting pipe 68 for transferring the solvent waste liquid from the stirring and mixing tank 63 to the filtration tank 64 is connected to the bottom of the stirring and mixing tank 63. A filter member 69 for collecting the agglomerated resin composition is installed inside the filtration tank 64, and the inside of the filtration tank 64 is divided into two regions by the filter member 69. Of the internal space in the filtration tank 64, the upper part from the filter member 69 is referred to as an unfiltered area 64a and the lower part is referred to as a post-filter area 64b. Moreover, the upper cover 64c of the filtration tank 64 is an openable type. The details of the filter member 69 will be described later. The post-filtration region 64b in the filtration tank 64 and the specific gravity difference separation tank 81 of the separation / recovery device 8 for aggregating / separating agent, which will be described later, are connected by a connecting pipe 70 for transferring the solvent waste liquid from the filtration tank 64 to the specific gravity difference separation tank 81. It is connected.

  In the middle of the connection pipes 65, 66, 68, and 70, pumps 71 to 74 are installed, respectively. The pumps 71 to 74 and the drive motor of the stirrer 67 are connected to the control device 100 (not shown in FIG. 2) via electrical wiring, and the operation is performed based on the control signal from the control device 100. Be controlled. The solvent waste liquid storage container 51 is provided with a second liquid level meter 75 for detecting the liquid level of the solvent waste liquid stored therein, and the control device 100 acquires the detection result at any time, The liquid level of the solvent waste liquid in the solvent waste liquid storage container 51 can be monitored.

  The aggregating / separating agent storage tank 62 stores, for example, an aqueous methanol solution that is a mixed solution of methanol and water, which are polar solvents, as an aggregating / separating agent that agglomerates the resin composition contained in the solvent waste liquid. Hereinafter, for convenience of explanation, a case where a methanol aqueous solution is used as the aggregating / separating agent will be described. In addition, as the coagulation / separation agent, various alcohol aqueous solutions other than methanol aqueous solution, polyether, paraffinic hydrocarbon having 6 or more carbon atoms, a compound selected from the group of polymer electrolyte compounds, or a mixture of two or more kinds of compounds. It may be adopted.

  When the liquid level of the solvent waste liquid in the solvent waste liquid storage container 51 becomes equal to or lower than the lower reference level C, the control device 100 activates the pump 71 and the pump 72. As a result, the solvent waste liquid from the solvent waste liquid storage tank 61 through the connection pipe 65 and the aqueous methanol solution transferred from the coagulation / separation agent storage tank 62 through the connection pipe 66 are supplied to the stirring and mixing tank 63 and mixed. The solvent waste liquid storage tank 61 stores, for example, untreated solvent waste liquid that has been discharged from the VOC generation facility 2. In the solvent waste liquid storage tank 61, for example, by providing a pipe (not shown), the solvent waste liquid may be transferred from the VOC generation facility 2 as needed.

  Note that the connection pipe 65 and the connection pipe 66 may be joined together, and in that case, the solvent waste liquid to which the methanol aqueous solution is added is supplied to the stirring and mixing tank 63. Further, when the solvent waste liquid and the methanol aqueous solution are supplied to the stirring and mixing tank 63, the weight ratio of the methanol aqueous solution to the solvent waste liquid is set in advance, and the operation time of each of the pump 71 and the pump 72 is controlled by the control device 100. Thus, both liquids are metered and mixed in a set weight ratio.

  In the stirring / mixing tank 63, the stirring blades of the stirrer 67 are rotationally driven by the drive motor, whereby the solvent waste liquid and the aqueous methanol solution in the stirring / mixing tank 63 are stirred and mixed. Here, while methanol exhibits hydrophilicity, the resin composition in the solvent waste liquid exhibits lipophilicity. When the solvent waste liquid in which such a lipophilic resin composition is dissolved exhibits hydrophilicity, for example, a methanol aqueous solution is stirred and mixed, the resin composition in the solvent waste liquid is not completely dissolved and aggregates.

  The solvent waste liquid in which the resin composition is agglomerated is sent from the bottom of the stirring and mixing tank 63 to the connection pipe 68 by the control device 100 operating the pump 73 and transferred to the filtration tank 64.

  The mixed waste liquid of the solvent waste liquid and the flocculent separation agent in which the resin composition is in the aggregated state is transferred to the unfiltered region 64 a of the filtration tank 64 through the connection pipe 68. The resin composition of the mixed waste liquid of the solvent waste liquid and the flocculent separation agent that has flowed into the unfiltered region 64 a is filtered (removed) when passing through the filter member 69. The filter member 69 is, for example, a filter for membrane separation, and the optimum pore diameter is selected so that the resin composition aggregated in the solvent waste liquid can be filtered.

The resin composition in the solvent waste liquid that has flowed into the filtration tank 64 and aggregated into a gel state is collected when passing through the filter member 69. As a result, it accumulates and remains on the filter member 69 as a residue. In addition, the control device 100 operates the pump 74 to send the remaining solvent waste liquid from the bottom of the filtration tank 64 to the connection pipe 70 after the resin composition is removed. The solvent waste liquid sent to the connection pipe 70 is transferred to the subsequent separation / recovery device 8 for the coagulating / separating agent.

  According to the resin composition separation and recovery device 6 having the above-described configuration, the resin composition contained in the solvent waste liquid discharged from the VOC generation facility 2 can be collected by the filter member 69 in the filtration tank 64. For example, the resin composition deposited as a residue on the filter member 69 can be easily recovered by opening the upper lid 64c in a state where the solvent waste liquid is not stored in the filtration tank 64. And the collect | recovered resin composition can be utilized as a resource, for example. For example, the recovered resin composition may be reused as a raw material for the adhesive or may be used as a solid fuel, which can contribute to effective utilization of resources.

  Further, according to the resin composition separation and recovery device 6 of FIG. 2, the resin composition can be recovered from the solvent waste liquid before being heated by the vaporization tank 52 of the waste liquid treatment apparatus 5 shown in FIG. Therefore, inconveniences such as the resin composition contained in the solvent waste liquid adhering to the inner surface of the vaporizing tank 52 and solidifying do not occur. As a result, it is possible to suppress the inner surface of the vaporization tank 52 from being contaminated by the solidified resin composition contained in the solvent waste liquid or the generation efficiency of the VOC gas from being lowered.

  In the present embodiment, the weight percentage of the flocculating / separating agent (here, methanol aqueous solution) added to the solvent waste liquid is adjusted within a predetermined range. The weight percentage of the flocculent separating agent added to the solvent waste liquid can be adjusted to a predetermined target value by adjusting the operation time of the pump 71 and the pump 72 by the control device 100, for example.

  Further, the methanol concentration of the aqueous methanol solution stored in the flocculating / separating agent storage tank 62 is adjusted to be a predetermined concentration. From the viewpoint of increasing the separation and recovery rate of the resin composition (aggregation rate of the resin composition and the cured state of the separated resin composition), for example, when the methanol concentration in the methanol aqueous solution is 50%, the methanol aqueous solution is used as the solvent waste liquid. The amount is preferably 50 parts by weight or more with respect to 100 parts by weight. Moreover, it is more preferable to set it as 75 weight part or more, and it is most preferable to set it as about 100 weight part. However, if the methanol aqueous solution is excessively added to the solvent waste liquid, the flocculating / separating agent is wasted and the labor for recovering the flocculating / separating agent using the flocculating / separating agent separation / recovery device 8 is increased. In addition, since the optimal weight percentage of the flocculent separating agent added to the solvent waste liquid varies depending on the methanol concentration in the methanol aqueous solution, the target value of the weight percentage may be determined according to the methanol concentration in the methanol aqueous solution. Good.

  Here, if the addition amount of the coagulation / separation agent added to the solvent waste liquid is increased, the aggregation rate is increased and the degree of curing of the resin composition obtained by aggregation is also increased. In order to remain as a residue on the filter member 69 when filtered by the filter member 69, the resin composition after aggregation needs to have a certain degree of hardness. The addition amount of the coagulating / separating agent to be added to the solvent waste liquid is preferably determined from the viewpoint of favorably maintaining the cured state of the resin composition obtained by separation from the solvent waste liquid. For example, in an aqueous methanol solution having a methanol concentration of 40%, the aqueous methanol solution is preferably at least 60 parts by weight or more with respect to 100 parts by weight of the solvent waste liquid. In addition, in a methanol aqueous solution having a methanol concentration of 30%, the methanol aqueous solution is preferably at least 140 parts by weight or more with respect to 100 parts by weight of the solvent waste liquid.

Next, with reference to FIG.3 and FIG.4, the detailed structure of the separation | separation collection | recovery apparatus 8 for flocculent separation agents is demonstrated. The separation / recovery device 8 for flocculating / separating agent includes a specific gravity difference separation tank 81, a distillation device 82, and the like as main components. In the specific gravity difference separation tank 81, the remaining resin composition-removed waste liquid after the resin composition is removed by the resin composition separation and recovery device 6 is transferred via the connection pipe 70. The waste liquid from which the resin composition has been removed contains an aqueous methanol solution (aggregation separation agent) added as an aggregation separation agent by the resin composition separation and recovery device 6.

  The specific gravity difference separation tank 81 is provided with a connection port with the connection pipe 70 at the bottom thereof, and the waste liquid from which the resin composition has been removed is supplied from the filtration tank 64 from the bottom. The specific gravity difference separation tank 81 is a storage tank for separating the resin composition-removed waste liquid supplied from the resin composition separation and recovery device 6 side by specific gravity difference. The resin composition-removed waste liquid supplied from the bottom to the specific gravity difference separation tank 81 is separated into a methanol aqueous solution having a large specific gravity and a solvent waste liquid having a small specific gravity by the specific gravity difference. Here, the solvent waste liquid separated by the difference in specific gravity from the methanol aqueous solution in the specific gravity difference separation tank 81 is referred to as “aggregated separation agent removed waste liquid”. In the upper (upper) region in the specific gravity difference separation tank 81, a solvent waste liquid layer 81a in which mainly the waste liquid after removal of the coagulating / separating agent is present is formed. Further, in the lower (lower) region in the specific gravity difference separation tank 81, an aggregating / separating agent layer 81b in which mainly an aqueous methanol solution exists is formed.

  One end of a connection pipe 76 is connected to the solvent waste liquid layer 81 a of the specific gravity difference separation tank 81, and the other end of the connection pipe 76 is connected to the solvent waste liquid storage container 51. In the example shown in FIG. 3, a connection pipe 76 is connected to the uppermost part of the solvent waste liquid layer 81a. Among the waste liquids after the removal of the flocculent separating agent separated by the specific gravity difference from the aqueous methanol solution in the specific gravity difference separation tank 81, the waste liquid after the removal of the flocculent separation agent overflowed the specific gravity difference separation tank 81 (overflow) It is transferred to the container 51.

  If the methanol aqueous solution in the coagulation / separation agent layer 81b of the specific gravity difference separation tank 81 is left to stand in the specific gravity difference separation tank 81 as it is, the methanol component will eventually elute to the solvent waste liquid layer 81a side, and the connecting pipe There is a risk of being sent out from 76. Therefore, in the separation / recovery device 8 for the flocculating / separating agent, the methanol is separated by distilling the waste liquid from which the resin composition has been removed in the specific gravity difference separation tank 81 and the aqueous methanol solution separated using the specific gravity difference by the distillation device 82. To do. And the elution to the solvent waste liquid tank 81a of a methanol component is reduced by returning the methanol aqueous solution which reduced methanol concentration to the solvent waste liquid layer 81a of the specific gravity difference separation layer 81. Hereinafter, the details of the distillation apparatus 82 will be described.

  The distillation apparatus 82 includes an evaporation tank 83, a methanol storage tank 84, a communication pipe 85, a methanol aqueous solution supply pipe 86, a return pipe 87, and the like. FIG. 4 is a partially enlarged view for explaining the detailed configuration of the distillation apparatus 82 and its peripheral devices. The evaporation tank 83 is supplied with a methanol aqueous solution, which is a used aggregating / separating agent subjected to specific gravity separation, from a specific gravity difference separation tank 81 through a methanol aqueous solution supply pipe 86. The methanol aqueous solution supply pipe 86 connects the aggregating / separating agent layer 81 b of the specific gravity difference separation tank 81 and the upper lid portion of the evaporation tank 83. A pump 88 is provided in the middle of the methanol aqueous solution supply pipe 86. When the pump 88 is operated based on a command from the control device 100, the aqueous methanol solution in the flocculating / separating agent layer 81 b of the specific gravity difference separation tank 81 is transferred to the evaporation tank 83 through the aqueous methanol solution supply pipe 86.

  The evaporation tank 83 is provided with a heater 89 for heating the aqueous methanol solution stored therein. The heater 89 has a flow path for flowing the heat medium supplied by the heat recovery device 90, and performs heat exchange between the heat medium flowing through the flow path and the aqueous methanol solution in the evaporation tank 83.

The thermal recovery device 90 includes a thermal recovery unit 91 and a heat medium transfer pipe 92 (see FIG. 1). The heat recovery unit 91 is a heat exchanger that is provided in the waste gas processing device 4 and recovers the heat generated by the combustion process of the VOC gas via a heat medium. In this embodiment, since water is used as the heat medium, hereinafter, it will be referred to as “heat medium water”, but other types of fluids may be used.

  A flow path for flowing heat medium water is formed inside the heat recovery unit 91, and the flow path of the heat recovery unit 91 and the flow path of the heater 89 are connected by a heat medium transfer pipe 92. ing. The heat medium transfer pipe 92 is provided with a pump (not shown). When this pump is operated, the heat medium water circulates through the heat medium transfer pipe 92. The pump installed in the heat transfer pipe 92 may be always operated while the apparatus is in operation.

  A part of the heat generated by the combustion process of the VOC gas in the waste gas processing device 4 is used to heat the heat transfer water flowing through the flow path of the heat recovery unit 91. The heated heat medium water is supplied to the heater 89 through the heat medium transfer pipe 92.

  The temperature of the heat medium water supplied to the heater 89 through the heat medium transfer pipe 92 is, for example, about 70 to 80 ° C. When heated heating medium water is supplied to the heater 89, the aqueous methanol solution in the evaporation tank 83 is heated. At that time, the water and methanol constituting the aqueous methanol solution hardly cause azeotropy, and only the methanol is evaporated to form a gas phase, and the water is maintained in the liquid phase.

  As shown in FIG. 4, a three-way valve 93 is provided at the bottom of the evaporation tank 83. In addition to the evaporation tank 83, the return pipe 87 and the separating agent recovery pipe 94 shown in FIG. The three-way valve 93 connects one of the return pipe 87 and the separating agent recovery pipe 94 to the evaporation tank 83 and blocks the other from the evaporation tank 83. The return pipe 87 is a pipe for returning the aqueous methanol solution taken out from the evaporation tank 83 to the coagulation / separation agent layer 81 b of the specific gravity difference separation tank 81. A pump 95 is provided in the middle of the return pipe 87. The three-way valve 93 allows the return pipe 87 to communicate with the evaporation tank 83 and to operate the pump 95. As a result, a solution in which methanol is separated by evaporation, that is, a methanol aqueous solution having a lower methanol concentration than the specific gravity difference separation tank 81 is transferred from the evaporation tank 83 to the coagulation / separation agent layer 81 b of the specific gravity difference separation tank 81.

  In the VOC treatment apparatus 1, as described above, the methanol aqueous solution obtained by the specific gravity difference separation in the specific gravity difference separation tank 81 is reduced in methanol concentration in the evaporation tank 83, and then sequentially aggregated in the specific gravity difference separation tank 81. It returns to the separating agent layer 81b. Thereby, the methanol concentration of the aqueous methanol solution in the aggregation / separation agent layer 81b can be kept low. Therefore, methanol hardly dissolves in the solvent waste liquid at the interface between the solvent waste liquid layer 81a and the coagulation / separation agent layer 81b in the specific gravity difference separation tank 81. Therefore, it is possible to suppress methanol from being transferred to the waste gas treatment device 4 and the waste liquid treatment device 5 in the subsequent stage through the connection pipe 76 and volatilizing.

  On the other hand, the methanol evaporated in the evaporation tank 83 flows from the upper part of the evaporation tank 83 into the communication pipe 85. The communication pipe 85 is provided with a condenser (cooler) 96. The condenser 96 has a flow path for flowing the refrigerant supplied by the cold energy recovery device 97, and agglomerates gaseous methanol by the refrigerant flowing through the flow path.

The cold energy recovery apparatus 97 includes a cold energy recovery unit 98 and a refrigerant transfer pipe 99 (see FIG. 1). The cold heat recovery unit 98 is a heat exchanger that covers the outer surface of the vaporization tank 52 of the waste liquid treatment apparatus 5 and collects the cold heat of the waste liquid from which the coagulating / separating agent has been removed in the vaporization tank 52 via a refrigerant. In this embodiment, since water is used as the refrigerant, it will be referred to as “refrigerant water” below, but other types of fluids may be used. For example, antifreezing agents such as ethylene glycol and propylene glycol, corrosion inhibitors, etc. are added to tap water so that the freezing point temperature is adjusted to 0 ° C. to −30 ° C. and corrosion of metal piping can be prevented. did,
A commercially available refrigerant (also called brine) may be used.

  A flow path for flowing coolant water is formed inside the cold heat recovery unit 98. In this configuration example, the cold recovery unit 98 is installed on the outer surface side of the vaporization tank 52. However, for example, in the vaporization tank 52, if the cold heat of the solvent waste liquid in the vaporization tank 52 can be recovered, May be installed.

  The flow path of the cold heat recovery unit 98 and the flow path of the condenser 96 are connected by a refrigerant transfer pipe 99. The refrigerant transfer pipe 99 is provided with a pump (not shown). When this pump is operated, the refrigerant water circulates through the refrigerant transfer pipe 99. The pump installed in the refrigerant transfer pipe 99 may be always operated while the VOC processing apparatus 1 is in operation.

  In the vaporization tank 52 in the waste liquid treatment apparatus 5, the gas from the outlet of the exhaust gas supply pipe 53 is blown into the waste liquid after removal of the coagulation / separation agent, whereby VOC in the waste liquid after removal of the coagulation / separation agent is vaporized. Then, when the VOC in the waste liquid after removal of the coagulation / separation agent is vaporized, the heat of the waste liquid after removal of the coagulation / separation agent is removed by the heat of vaporization. As a result, the liquid temperature of the waste liquid after removal of the coagulation / separation agent in the vaporization tank 52 is lowered. The cold energy recovery unit 98 of the cold energy recovery device 97 recovers cold energy by exchanging heat between the coolant water flowing through the flow path of the cold energy recovery unit 98 and the waste liquid from which the coagulation / separation agent has been removed.

  As described above, the coolant water cooled in the cold recovery unit 98 provided in the vaporization tank 52 is supplied to the condenser 96 through the coolant transfer pipe 99. The gaseous methanol introduced from the evaporation tank 83 to the communication pipe 85 is cooled by low-temperature refrigerant water flowing through a passage of a condenser 96 provided so as to cover the outer peripheral surface of the communication pipe 85. As a result, gaseous methanol is condensed in the communication pipe 85. The methanol condensed in the communication pipe 85 is dropped into the methanol storage tank 84 communicating with the communication pipe 85, and the methanol liquid is stored in the methanol storage tank 84.

  The bottom of the methanol storage tank 84 and the separating agent recovery pipe 94 are connected by a methanol extraction pipe 101 for taking out the purified methanol liquid. A shutoff valve 102 is provided in the middle of the methanol take-out pipe 101. When the shutoff valve 102 is closed, the methanol storage tank 84 and the separating agent recovery pipe 94 are shut off. Further, one end side of the separating agent recovery pipe 94 is connected to the bottom of the vaporizing tank 52 in the waste liquid treatment apparatus 5, and a shutoff valve 103 is provided in the vicinity of the connecting portion with the vaporizing tank 52 in the separating agent recovery pipe 94. Is provided. Further, the other end side of the separating agent recovery pipe 94 is connected to the coagulating / separating agent storage tank 62, and a pump 104 is provided in the middle of the separating agent recovery pipe 94.

  In the present embodiment, the methanol concentration of the aqueous methanol solution stored in the flocculating / separating agent storage tank 62 is adjusted to be a predetermined concentration (hereinafter referred to as “set reference concentration”). In order to increase the separation / recovery rate of the resin composition and to safely handle the combustible methanol, the methanol concentration in the aqueous methanol solution is preferably in the range of 20% by weight to 90% by weight. Further, it is more preferably in the range of 30% by weight to 80% by weight, and most preferably about 50% by weight.

  The methanol solution stored in the methanol storage tank 84 is supplied to the flocculating / separating agent storage tank 62 through the separating agent recovery pipe 94 so that the aqueous methanol solution in the flocculating / separating agent storage tank 62 has the set reference concentration. At that time, for example, the return pipe 87 and the evaporation tank 83 are communicated with the three-way valve 93, and each valve is controlled so that the shutoff valve 103 is closed and the shutoff valve 102 is opened. By operating the pump 104 in this state, the methanol liquid stored in the methanol storage tank 84 is transferred to the coagulation / separation agent storage tank 62 via the separation agent recovery pipe 94.

  At that time, if only the methanol solution is replenished to the flocculating / separating agent storage tank 62, the methanol concentration in the flocculating / separating agent storage tank 62 may be excessively higher than the set reference concentration. Therefore, it is preferable to adjust the methanol concentration in the flocculating / separating agent storage tank 62 so that it does not greatly deviate from the set reference concentration by replenishing the flocculating / separating agent storage tank 62 with an appropriate amount of water from a water supply line (not shown). . In the aqueous methanol solution stored in the flocculating / separating agent storage tank 62, methanol is more easily dissipated than water. Therefore, for example, a methanol concentration sensor (not shown) may be installed in the flocculating / separating agent storage tank 62, and the supply amounts of methanol and water may be adjusted according to the detection result of the methanol concentration sensor.

  Further, instead of separately supplying water from the water supply line (not shown) described above, the evaporating tank 83 and the separating agent recovery pipe 94 may be communicated with the three-way valve 93. The aqueous methanol solution in the evaporation tank 83 may be supplied to the flocculating / separating agent storage tank 62 through the separating agent recovery pipe 94. By adjusting the supply amount of the aqueous methanol solution from the evaporation tank 83 and the supply amount of the methanol solution from the methanol storage tank 84, the methanol concentration of the aqueous methanol solution in the coagulation / separation agent storage tank 62 is greatly deviated from the set reference concentration. Can be avoided.

  As described above, according to the separation / recovery device 8 for the flocculating / separating agent, before the methanol aqueous solution added to the solvent waste liquid by the resin composition separation / recovery device 6 is subjected to the combustion treatment in the waste gas treatment device 4. It can be recovered. Moreover, the recovered methanol aqueous solution can be purified by the distillation device 82 provided in the separation / recovery device 8 for the flocculating / separating agent, and can be reused as the flocculating / separating agent. Therefore, there is an effect that the running cost of the VOC processing device 1 can be reduced.

  Further, in the distillation apparatus 82, the thermal energy and cold energy necessary for distilling the used flocculating / separating agent are the waste heat of the waste gas treatment apparatus 4 or the waste liquid treatment that was originally discarded. The waste heat of the device 5 (warm heat in the waste gas treatment device 4 and cold heat in the waste liquid treatment device 5) is used. Therefore, it is excellent also from a viewpoint of energy saving, and contributes to the reduction of the running cost of the VOC processing apparatus 1.

Next, the present invention will be specifically described with reference to examples.
<Example 1>
In Example 1, a solvent waste liquid containing ethyl acetate as a VOC component and an ether-based adhesive as a solid content made of a nonvolatile resin composition was prepared. The resin composition (solid content) concentration in the solvent waste liquid is 26.4% by weight. Then, an aqueous methanol solution having a methanol concentration of 100% by weight was added to the solvent waste liquid as an aggregating / separating agent. After that, a stirring and mixing process was performed, and a test for separating and removing the aggregated resin composition by filtration was performed. At that time, the resin composition recovery rate was measured when the weight part of the methanol aqueous solution to be added was changed with respect to 100 parts by weight of the solvent waste liquid. The test results are shown in Table 1-1, Table 1-2, FIG. 5 and FIG.

  As shown in Table 1-1 and Table 1-2, the weight of the solvent waste liquid is set to a constant 100 g, and the addition amount (weight) of the aqueous methanol solution added to the solvent waste liquid is in the range of 5 to 100 g in increments of 5 g. Set. That is, the addition amount of the methanol aqueous solution added to 100 parts by weight of the solvent waste liquid was changed every 5 parts by weight within a range from 5 parts by weight to 100 parts by weight.

  In Table 1-1 and Table 1-2, “whole liquid” in the table means a solvent waste liquid to which an aqueous methanol solution is added. The “addition amount of the flocculating / separating agent” is the addition amount (parts by weight) of the aqueous methanol solution. “Aggregating / separating agent / total liquid” means the methanol concentration (% by weight) with respect to the total liquid obtained by adding the solvent waste liquid and the aqueous methanol solution. The “resin composition concentration before removal” is a percentage by weight with respect to the total liquid of the resin composition before removing (collecting) the aggregated resin composition. The “resin composition concentration after removal” is the percentage by weight with respect to the total liquid of the resin composition after removing (collecting) the aggregated resin composition. The “resin composition recovery rate” is a value obtained by subtracting the resin composition concentration after removal from the resin composition concentration before removal.

  FIG. 5 is a graph showing the relationship between the added amount (parts by weight) of the methanol aqueous solution added to 100 parts by weight of the solvent waste liquid and the resin composition concentration after removal. FIG. 6 is a graph showing the relationship between the addition amount (parts by weight) of the methanol aqueous solution added to 100 parts by weight of the solvent waste liquid and the resin composition recovery rate. From each table and FIGS. 5 and 6, when the addition amount of the methanol aqueous solution added to 100 parts by weight of the solvent waste liquid is 35 parts by weight or more, the resin composition concentration after the removal rapidly decreases, and the resin composition It was confirmed that the trend of increasing the product recovery rate became remarkable. Furthermore, when the addition amount (parts by weight) of the methanol aqueous solution added was 65 parts by weight or more with respect to 100 parts by weight of the solvent waste liquid, the increase in the recovery rate was gradually reduced.

<Example 2>
Example 2 is the same as Example 1 except that the recovery test of the resin composition is performed by changing the methanol concentration (% by weight) of the aqueous methanol solution added to the solvent waste solution. The concentration of the resin composition in the solvent waste liquid was also 26.4% by weight, the same as in Example 1. The test results of Example 2 are shown in Table 2-1, Table 2-2, FIG. 7, and FIG.

In Tables 2-1 and 2-2, the “methanol concentration” in the table is the weight percent of methanol in the aqueous methanol solution that is an aggregating and separating agent. The definitions of other terms are the same as those in the first embodiment. FIG. 7 is a graph showing the relationship between the amount (parts by weight) of the methanol aqueous solution added to 100 parts by weight of the solvent waste liquid and the resin composition concentration after removal. FIG. 8 is a graph showing the relationship between the amount (parts by weight) of aqueous methanol solution added to 100 parts by weight of the solvent waste liquid and the resin composition recovery rate. In Example 2, the methanol concentration (% by weight) of the aqueous methanol solution was set to five levels of 30%, 40%, 50%, 75%, and 100% by weight.

  From Table 2-1, Table 2-2, FIG. 7, and FIG. 8, when the methanol concentration in the methanol aqueous solution was 50 wt%, the resin composition recovery rate was the best. In addition, when the relationship between the amount of methanol aqueous solution added to the solvent waste liquid and the resin composition recovery rate is compared for each methanol concentration, the resin composition in the case where the methanol concentration is 40% by weight after the case where the methanol concentration is 50% by weight A high recovery result was obtained. Moreover, the result that the resin composition recovery rate fell in order of 75 weight%, 100 weight%, and 30 weight% sequentially was obtained. When the methanol concentration was 50% by weight, the resin composition contained in the solvent waste liquid could be satisfactorily separated even when the amount of the methanol aqueous solution added was about 20 parts by weight with respect to 100 parts by weight of the solvent waste liquid. .

<Other embodiments>
The embodiment described above is an example for explaining the present invention, and various modifications can be made to the above-described embodiment without departing from the gist of the present invention.

  Moreover, in the VOC processing apparatus 1 of this embodiment, the waste liquid processing apparatus 5 supplies the VOC gas vaporized from the waste liquid from which the coagulation / separation agent has been removed to the waste gas processing apparatus 4 as fuel. And although the VOC gas supplied to the waste gas processing apparatus 4 as a fuel is combusted in the waste gas processing apparatus 4, it is not limited to this. For example, instead of the waste gas treatment device 4, a combustion treatment device that performs a combustion treatment of a liquid volatile organic compound (VOC) contained in the solvent waste liquid may be arranged. In that case, the said combustion processing apparatus respond | corresponds to the VOC processing apparatus which concerns on this invention. The resin composition in the solvent waste liquid can also be suitably recovered by providing the resin composition separation / recovery device 6 according to the present invention in the preceding stage of such a combustion treatment device.

In addition, the resin composition separation and recovery device 6 may add an aggregating and separating agent other than the methanol aqueous solution to the solvent waste liquid. For example, as the aggregating / separating agent, an alcohol aqueous solution, a polyether, a paraffin hydrocarbon having 6 or more carbon atoms, a compound selected from the group of compounds of polymer electrolytes, or a mixture of two or more compounds may be employed. .
Examples of the alcohol aqueous solution include various alcohol aqueous solutions using methanol, ethanol, IPA, glycerin and the like. In particular, a methanol aqueous solution is preferably used from the viewpoint of cost and ease of handling. As the aqueous methanol solution, aqueous methanol solutions having various concentrations can be used, but an aqueous methanol solution having a methanol concentration of 20 to 80% is preferable from the viewpoint of safety against fire and economy. High-purity methanol with a methanol concentration exceeding 80% is not only expensive, but also increases the risk of ignition. In particular, pure methanol having a methanol concentration of 100% is not only very expensive but also difficult to handle due to the extremely high risk of ignition.

  Examples of the polyether include, but are not necessarily limited to, polybutanediol, polyethylene glycol, polypropylene glycol, polyoxymethylene, polyvinyl methyl ether, polycellulose ether, polyepichlorohydrin, and polyphenylene oxide. Never happen.

Examples of paraffinic hydrocarbons having 6 or more carbon atoms include n-paraffins (linear saturated hydrocarbons) such as hexane, heptane, octane, nonane, decane, undecane, dodecane, and tetradecane, 2-methylhexane, and 3-methyl. Hexane, 3-ethylpentane, 2,2-dimethylpentane, 2,3-dimethylpentane, 2,4-dimethylpentane, 3,3-dimethylpentane, 2,2,3-trimethylbutane, 3-methylheptane, 2 , 2-dimethylhexane, 2,3-dimethylhexane, 2,4-dimethylhexane, and other isoparaffins (branched saturated hydrocarbons) and derivatives of these saturated hydrocarbons.
These paraffinic hydrocarbons are preferably liquid at room temperature, and may be used in the form of a mixture of two or more.

  Examples of the polymer electrolyte include those in which a sulfonic acid group is introduced into each of homopolymers such as polyether ketone, polysulfone, polyether sulfone, poly (arylene ether), polyimide, polyphenylene, and polyphenylene sulfide. It is done.

  Here, in the case of using a flocculating / separating agent such as paraffin hydrocarbons that cannot be separated from the solvent waste liquid due to the difference in specific gravity and does not require a distillation operation, The distillation apparatus 82 is not operated. Further, the return pipe 87 is communicated with the evaporation tank 83 through the three-way valve 93, and the pumps 88 and 95 are stopped even during operation of the apparatus.

  And the control apparatus 100 starts the pumps 71-74 in the state which stopped the distillation apparatus 82, for example, when the liquid level of the waste liquid storage container 51 becomes the lower reference level C or less. When the above control is performed, the aggregated resin composition is collected by the filter member 69 in the same manner as when the aqueous methanol solution is used as the aggregation separation agent. Therefore, the resin composition deposited as a residue on the filter member 69 can be collected.

  Thereafter, the solvent waste liquid containing the flocculent separation agent that cannot be separated from the solvent waste liquid due to the specific gravity difference is transferred to the specific gravity difference separation tank 81. Here, since the pumps 88 and 95 are stopped, the solvent waste liquid is directly transferred to the vaporization tank 52 through the solvent waste liquid storage container 51. The solvent waste liquid supplied to the vaporization tank 52 vaporizes the VOC component by blowing exhaust gas from the exhaust gas supply pipe 53, but the aggregating / separating agent contained in the solvent waste liquid precipitates at the bottom of the vaporization tank 52. . Therefore, it is preferable to collect the aggregated separating agent precipitated at the bottom of the vaporizing tank 52 through the separating agent recovery pipe 94 by opening the shut-off valve 103 at an appropriate timing and operating the pump 104. The recovered flocculating / separating agent can be replenished to the flocculating / separating agent storage tank 62.

  The preferred embodiments of the present invention have been described above, but the present invention is not limited to these, and can include combinations thereof as much as possible.

DESCRIPTION OF SYMBOLS 1 ... VOC processing apparatus 2 ... VOC generation equipment 4 ... Waste gas processing apparatus 5 ... Waste liquid processing apparatus 6 ... Separation / recovery apparatus 8 for resin composition Apparatus 52 ... Vaporization tank 63 ... Agitation mixing tank 64 ... Filter tank 69 ... Filter member 81 ... Specific gravity difference separation tank 82 ... Distillation apparatus 83 ... Evaporation tank 85 ... Communication pipe 89 ... Heater 90 ... Thermal recovery device 91 ... Thermal recovery unit 96 ... Condenser 97 ... Cold recovery unit 98 ... Cold recovery unit

Claims (5)

Separating and recovering the resin composition from the solvent waste liquid by aggregating the non-volatile resin composition contained in the solvent waste liquid containing the organic solvent, adding an aggregating and separating agent to the solvent waste liquid Equipment,
After the resin composition is recovered from the solvent waste liquid by the resin composition separation and recovery device, the residual solvent waste liquid is supplied, and the volatile organic compound contained in the supplied residual solvent waste liquid is burned. A VOC processing device to process;
A VOC processing system comprising: The resin composition separation and recovery device includes:
A solvent waste liquid storage tank in which the solvent waste liquid is stored;
A flocculating / separating agent storage tank in which the flocculating / separating agent is stored;
A stirring and mixing tank to which the solvent waste liquid from the solvent waste liquid storage tank and the aggregation separation agent from the aggregation separation agent storage tank are supplied;
A mixing unit that stirs and mixes the solvent waste liquid and the flocculating / separating agent by stirring means provided in the stirring and mixing tank;
Filtration means for filtering the resin composition aggregated by stirring and mixing the solvent waste liquid and the aggregation separating agent;
The VOC processing system according to claim 1, comprising:   From the residual solvent waste liquid after the resin composition is recovered from the solvent waste liquid by the resin composition separation recovery apparatus, which is disposed between the resin composition separation recovery apparatus and the VOC combustion treatment apparatus. The VOC treatment system according to claim 1, further comprising a separation / collection device for the aggregation / separation agent that separates and collects the aggregation / separation agent. The separation / collection device for the flocculant separation agent
A specific gravity difference separation tank for separating the aggregating and separating agent from the residual solvent waste liquid using a specific gravity difference;
A distillation purification apparatus for purifying the flocculating / separating agent by distilling the flocculating / separating agent separated from the solvent waste liquid by the specific gravity difference separation tank;
The VOC processing system according to claim 3, wherein:   The aggregating and separating agent is one or two or more compounds selected from the group consisting of an alcohol aqueous solution, a polyether, a paraffinic hydrocarbon having 6 or more carbon atoms, and a polymer electrolyte. Item 5. The VOC processing system according to any one of Items 1 to 4.

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