JP2007209858A - Solvent recovery device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a device for effectively recovering a solvent from a mixture containing the solvent and solid matter. <P>SOLUTION: This device for recovering the solvent from the mixture containing the solvent and thermosoftening and/or thermosetting solid matter is provided with: an evaporation tank; a mixture container; a condenser; a solvent recovery tank; a vapor heating means; and a vapor jetting means. The mixture container is provided in the evaporation tank, and receives the mixture. The vapor jetting means is provided at the upper part of the mixture container and disposed to jet superheated vapor over the mixture. Part of vapor of the solvent generated by jetting the superheated vapor is condensed in the condenser and recovered in the solvent recovery tank. Remaining vapor of the solvent is further heated by the vapor heating means to be superheated vapor, and jetted over the mixture from the vapor jetting means. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a solvent recovery apparatus. More specifically, the present invention relates to an apparatus for recovering a solvent from waste generated in a manufacturing process such as paint, paint, gravure ink, and adhesive.

  Conventionally, solids such as organic substances such as plastics or inorganic substances are generally dissolved or dispersed in a solvent in wastes produced in the manufacturing process of gravure inks and paints. This solid content is sticky, easily embraces the solvent, and has a property of softening when heated (thermal softening property) and / or a property of curing when heated (thermosetting property). This thermosoftening solid content dissolves in the hot solvent, or the viscosity decreases by heating, but it is easy to solidify when cooled, and the recovery of the solvent is completed. The recovery becomes difficult and the solvent is contained, so that it becomes difficult to treat as waste. On the other hand, the thermosetting solid content is solidified when heated, and like the thermosoftening solid content, it is difficult to recover from the evaporation tank and contains a solvent, so that it is difficult to treat as a waste.

  Conventionally, the recovery of the solvent from the waste is performed by putting the waste into an evaporation tank, applying heat from the outside to evaporate the solvent, and condensing the evaporated solvent with a condenser or the like. In this method, as the solvent in the waste evaporates, the solid matter such as organic matter or inorganic matter contained in the waste is deposited as a solid matter on the heating section of the evaporation tank (for example, the wall surface of the evaporation tank, the heating coil). In addition, the heat transfer efficiency is lowered and the solids are difficult to process.

  Furthermore, a method is known in which water vapor is directly supplied into the waste of the evaporation tank, and the solvent is evaporated by the heat to recover the solvent. However, in this case, water vapor is also collected together with the solvent, so that water is mixed in the collected solvent. For this reason, the process of further separating and recovering the solvent is required. Furthermore, water (steam) may react with or bind to the sticky solid contained in the waste, or may be taken into the solid, making it difficult to treat the waste.

  On the other hand, Patent Document 1 discloses a method for recovering a solvent from plastic. This patent document 1 introduces waste plastic before complete melting into a melting tank, melts it, performs thermal decomposition, and generates harmful gas, non-condensable hydrocarbon gas, low boiling point product and high boiling point by thermal decomposition. It describes a method for pyrolyzing waste plastics, separating the product into high-boiling products, reheating the high-boiling product, circulating a part to the pyrolysis tank, and extracting the pyrolysis residue from the bottom of the pyrolysis tank. In this method, in order to heat as mildly as possible, a part of the high boiling point product is refluxed. However, since it is insufficient as a heat source, the pyrolysis tank is heated. Therefore, the pyrolysis residue is likely to adhere to the pyrolysis tank. Therefore, it is necessary to provide a stirrer and provide a scraper at the tip of the stirring blade to peel off the thermal decomposition residue.

  When using such an apparatus, when recovering the solvent from the waste containing the heat-softening solid content, the solid content is sticky and thus easily adheres to the evaporation tank. And once attached, it is difficult to peel off, thermal efficiency deteriorates, solvent recovery cannot be performed efficiently, and peeling takes time.

  In Patent Document 2, in order to efficiently recover a solvent from a mixture containing a solvent and a thermosoftening and / or thermosetting solid content, a part of the solvent vapor contained in the mixture is heated to produce superheated steam. A solvent recovery method is disclosed that is introduced into a mixture and evaporated to recover the solvent. In this method, the solvent is efficiently recovered, but since the superheated steam is introduced by introducing a nozzle into the mixture, the viscosity of the solid matter increases as the evaporation proceeds, and the superheated steam from the nozzle becomes insufficiently supplied. The solvent recovery efficiency tends to decrease. In addition, there is a problem that a solid collection device becomes large.

Thus, there is a need for a method and apparatus for efficiently recovering a solvent from a mixture containing the solvent and thermosoftening and / or thermosetting solids.
JP 7-268354 A JP 2005-58864 A

  An object of this invention is to provide the apparatus which collect | recovers a solvent efficiently from the mixture (waste) containing a solvent and thermosoftening and / or thermosetting solid content, such as paint waste.

  The present invention provides an apparatus for recovering a solvent from a mixture containing the solvent and thermosoftening and / or thermosetting solids. This apparatus comprises an evaporation tank, a mixture storage container, a condenser, a solvent recovery tank, a steam heating means and a steam injection means, the mixture storage container is provided in the evaporation tank, and the mixture is introduced into the mixture storage container, The vapor injection means is provided at an upper portion of the mixture container and is arranged to inject superheated steam onto the mixture, and a part of the solvent vapor generated by the injection of the superheated steam is the condenser. In the solvent recovery tank, the remaining solvent vapor is further heated by the vapor heating means to be superheated vapor, and is injected onto the mixture from the vapor injection means.

  The present invention also provides a method for recovering solids from a mixture containing a solvent and thermosoftening and / or thermosetting solids using the above apparatus. The method comprises: supplying the mixture to a mixture storage container in an evaporation tank; injecting superheated steam from the top of the mixture using vapor injection means; evaporating the solvent; a part of the evaporated solvent And collecting the solid content in the mixture container from which the solvent has been removed.

  The present invention further provides a method for separating solvent and solids from a mixture containing the solvent and thermosoftening and / or thermosetting solids. The method comprises: supplying the mixture to a mixture storage container in an evaporation tank; injecting superheated steam onto the mixture to evaporate the solvent; recovering a part of the evaporated solvent; Heating the remaining part of the solvent with a steam heating means and circulating it as superheated steam; and recovering the solid content in the mixture container from which the solvent has been removed.

  In one embodiment, in the step of evaporating the solvent by injecting superheated steam from the top of the mixture using the vapor injection means, after the solvent of the mixture evaporates, a new mixture is added to the mixture storage container. And repeat the above process.

  In the solvent recovery apparatus of the present invention, a mixture storage container is disposed in an evaporation tank, a mixture containing a solvent and a thermosoftening and / or thermosetting solid content is introduced into the mixture storage container, and an upper part of the mixture storage container is introduced. The superheated steam is sprayed from above the mixture using the steam spraying means provided in the above. Therefore, the solvent can be evaporated without clogging the nozzle, and the solid content remains in the mixture storage container, so that the mixture storage container can be easily discharged out of the evaporation tank. That is, since it is not necessary to heat the evaporation tank from the outside, the solvent can be efficiently recovered. Moreover, since the solid content in the mixture does not adhere to the wall surface of the evaporation tank or does not burn by using the mixture storage container, it is very easy to discharge the solid matter. Furthermore, if necessary, the solid matter can be discarded together with the container.

  The solvent recovery apparatus and the solvent recovery method of the present invention will be described with reference to FIG. The solvent recovery apparatus 1 of the present invention includes an evaporation tank 2, a mixture storage container 3, a vapor injection unit 4, a condenser 11, a solvent recovery tank 12, and a vapor heating unit 18. The evaporation tank 2 is provided with a mixture inlet 6 for introducing a mixture as a raw material, a nitrogen gas inlet 16, and piping for extracting the generated solvent vapor 7. Further, the evaporation tank 2 is configured such that the mixture storage container 3 can be freely attached and detached (in / out), and the evaporation tank 2 is provided with the mixture storage container 3. A vapor injection means 4 (for example, one or a plurality of nozzles) is disposed above the mixture storage container 3 and is configured to eject superheated steam onto the mixture 5. The solvent vapor 7 from the evaporation tank 2 is partly distributed to the condenser 11 by the control valve 10 and the remaining part to the steam heating means 8 and heated by the steam heating means 8 to be heated as the superheated steam by the steam injection means 4 ( For example, it is configured to be supplied to a nozzle).

  A method for recovering a solvent from a mixture containing a solvent and a thermosoftening and / or thermosetting solid content will be described using the apparatus 1 of the present invention as an example. First, the mixture 5 is introduced from the mixture inlet 6 into the mixture storage container 3 of the evaporation tank 2 provided with the mixture storage container 3. The evaporation tank 2 is filled with nitrogen gas from the nitrogen gas inlet 16 so that oxygen does not enter. Next, the blower 9 is operated to introduce the nitrogen gas from the evaporation tank 2 into the steam heating means 8, and the heated nitrogen gas is injected from above the mixture 5 in the mixture storage container 3 from the steam injection means 4. When the temperature of the mixture 5 rises due to the heated nitrogen gas, the solvent evaporates. As the solvent vapor is generated, the pressure in the evaporation tank 2 increases. When the pressure in the evaporation tank 2 becomes higher than the pressure set at the outlet of the condenser 11, a part of the steam and nitrogen gas is guided to the condenser 11 via the control valve 10. Nitrogen gas is released into the atmosphere, while the solvent vapor 7 is condensed and recovered. The remaining part of the gas discharged from the evaporation tank 2 is repeatedly circulated through the steam heating means 8, whereby nitrogen gas is gradually removed and only the solvent vapor 7 is obtained. By further repeating the circulation, a part of the solvent vapor discharged from the evaporation tank 2 is guided to the condenser 11 to recover the solvent, and the remaining part of the vapor is supplied to the steam heating means 8 and further heated. Steam (superheated steam) is circulated to the evaporation tank 2.

  The solvent liquefied by the condenser 11 is stored in the solvent recovery tank 12, and the solvent 14 is recovered by the solvent recovery pump 13.

  In the apparatus 1 of the present invention, the solvent is evaporated by injecting superheated steam onto the mixture 5 stored in the mixture storage container 3. As a result, the vapor jetting means 4 (for example, the nozzle) does not come into contact with the mixture 5, so that the nozzle is not clogged. Further, the solvent can be efficiently evaporated while the solid matter remains in the mixture container 3 as it is. Further, when the evaporation of the solvent proceeds by jetting superheated steam, the temperature of the solid matter rises from the boiling point of the solvent. Therefore, most of the solvent in the solid is recovered. If the temperature of the solid is set in advance, the concentration of the solvent in the solid can be set to a predetermined concentration. When the solvent to be evaporated is exhausted, the mixture 5 is again supplied into the mixture container 3 and superheated steam is injected to generate solvent vapor, and the same method as described above is repeated. The solid substance derived from the added mixture 5 is laminated on the first solid substance. FIG. 2 shows the solid state of the stack when the batch operation is repeated in this way. As shown in FIG. 2, the solid material 17 is formed in layers in the mixture container 3.

  Moreover, it can evaporate continuously by injecting superheated steam, supplying the mixture 5 continuously. In this case, it is preferable to stop the supply of the mixture 5 once the solid has reached a predetermined thickness, because the solvent can be completely evaporated. This method also produces a layered solid. In addition, in the case of a thermoplastic solid content, the solid substance of the gum sheet state of a soft state which does not contain a solvent arises.

  As described above, the solid material 17 is accumulated in the mixture storage container 3 provided in the evaporation tank 2. When the mixture container 3 is filled with the solid material 17, the solid material 17 is taken out and the above operation is repeated again. Alternatively, the mixture storage container 3 in which the solid matter 17 is accumulated may be taken out and replaced with a new mixture storage container 3. By preparing two each of the evaporation tank 2 and the mixture storage container 3, it is possible to switch the operation when one of the solvent evaporation is completed and to operate continuously.

  If necessary, it is preferable to completely remove the solvent. In order to further remove the solvent from the solid 17 or to dry it, for example, a vacuum pump 15 can be used. This step may be performed in the evaporation tank 2 or may be performed by another device. When evacuated, the solvent can be evaporated by the heat of the solid.

  The material and shape of the mixture storage container 3 are not particularly limited as long as they are not dissolved in a solvent. Considering disposal of the solid material 17, for example, a waste drum can, a heat-resistant resin bag (for example, Teflon (registered trademark)), a cloth bag, or the like can be used. These can be discarded together with the container 3 containing the solid material 17.

  In order to further use the solid material 17, the shape of the mixture storage container 3 can be a square, a cylinder, or the like, which can be used for combustion, landfilling, or the like. Furthermore, the dried solid material 17 can be made into a powder by shaving with a lathe, for example.

  By using the solvent recovery apparatus of the present invention, it is possible to evaporate the solvent contained in the waste containing sticky thermosoftening and / or thermosetting solids by jetting superheated steam. Therefore, it is possible to recover the solvent very efficiently. In the solvent recovery apparatus of the present invention, the solid matter remains in the mixture storage container as it is, and the solid matter does not accumulate in the evaporation tank, so that the treatment of the solid matter is extremely easy. Therefore, the apparatus of the present invention is suitably used for the treatment of waste liquid containing sticky solids such as waste liquid during ink production.

It is a schematic diagram which shows the structure of the solvent collection | recovery apparatus of this invention. It is a schematic diagram which shows the state of the solid substance collect | recovered using the solvent collection | recovery apparatus of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Solvent recovery apparatus 2 Evaporation tank 3 Mixture storage container 4 Steam injection means 5 Mixture 6 Mixture inlet 7 Solvent vapor 8 Steam heating means 9 Blower 10 Control valve 11 Condenser 12 Solvent recovery tank 13 Solvent recovery pump 14 Recovery solvent 15 Vacuum pump 16 Nitrogen gas inlet 17 Solid

Claims (4)

An apparatus for recovering a solvent from a mixture containing the solvent and a thermosoftening and / or thermosetting solid content,
Evaporation tank, mixture storage container, condenser, solvent recovery tank, steam heating means and steam injection means,
The mixture storage container is provided in an evaporation tank, and the mixture storage container is introduced with the mixture;
The steam injection means is provided at the top of the mixture container and is arranged to inject superheated steam onto the mixture;
A part of the solvent vapor generated by the injection of the superheated steam is condensed by the condenser and collected in the solvent recovery tank, and the remaining solvent vapor is further heated by a steam heating means to be superheated steam, A solvent recovery device configured to be injected onto the mixture from a vapor injection means. A method for recovering solids from a mixture containing a solvent and thermosoftening and / or thermosetting solids using the apparatus of claim 1,
Supplying the mixture to a mixture storage container in an evaporation tank;
Jetting superheated steam from the top of the mixture using vapor jet means to evaporate the solvent;
Recovering a portion of the evaporated solvent with a condenser; and
Recovering the solid content in the mixture container from which the solvent has been removed. A method for separating a solvent and a solid from a mixture containing the solvent and a thermosoftening and / or thermosetting solid, comprising:
Supplying the mixture to a mixture storage container in an evaporation tank;
Jetting superheated steam onto the mixture to evaporate the solvent;
Recovering a portion of the evaporated solvent;
Heating the remaining part of the evaporated solvent with a steam heating means and circulating it as superheated steam; and recovering the solid content in the mixture container from which the solvent has been removed.   In the step of evaporating the solvent by injecting superheated steam from the upper part of the mixture using the vapor injection means, after the solvent of the mixture evaporates, supply a new mixture to the mixture container, and 4. A method according to claim 2 or 3 that is repeated.

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