JP2009144031A - Method of recovering vinyl chloride based resin and recovery treatment apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a recovery method and a recovery treatment apparatus for vinyl chloride based resins which enable an efficient long-term continuation operation. <P>SOLUTION: The apparatus 1 recovers a vinyl chloride based resin in waste comprising the vinyl chloride based resin and has a dissolution tank 3 for mixing a solvent which dissolves a vinyl chloride based resin in waste and a waste comprising the vinyl chloride based resin to dissolve the vinyl chloride in the waste in the solvent, a resin deposition tank 5 for depositing the vinyl chloride resin from the vinyl chloride based resin solution to form a slurry containing a deposit, a centrifugal separator 9 for separating and recovering the vinyl chloride based resin from the slurry, and further a crusher 6 for crushing a solid material in the slurry between the resin deposition tank 5 and the centrifugal separator 9. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method for recovering vinyl chloride resin in waste containing vinyl chloride resin, and a recovery processing apparatus.

  Vinyl chloride resins such as vinyl chloride resin and vinylidene chloride resin are excellent in processability and are inexpensive polymers, so they are used in various applications like polyolefins such as polyethylene and polypropylene, and other general-purpose polymers such as polyester. Has been. However, such general-purpose polymers are mass-produced not only in the field of basic materials having a long life cycle, but also as commodities having a short service life such as daily necessities. Therefore, environmental destruction due to mass disposal is a problem.

  Examples of wastes mainly composed of vinyl chloride resin include vinyl chloride resin pipe materials such as PVC pipes and joints, vinyl chloride sheets such as agricultural vinyl chloride sheets and waterproof sheets, wallpaper base materials, and waste wires And the like. Most of such wastes are disposed of by landfill or incineration. However, the vinyl chloride resin cannot be decomposed in nature and is one of the causative substances that generate dioxins by incineration, so it is necessary to consider the influence on the environment.

  For this reason, various recovery methods for recovering and reusing vinyl chloride resin from waste containing vinyl chloride resin have been studied. For example, a method in which waste is dissolved in a solvent in which a vinyl chloride-based resin can be dissolved and the vinyl chloride-based resin is recovered from the solution, so-called solution treatment, has been studied.

  As an example of the solution treatment, for example, Patent Document 1 discloses a method for recovering a vinyl chloride resin from a waste containing a vinyl chloride resin, which includes a solvent capable of dissolving the vinyl chloride resin and the waste. Removing insoluble solids from the heated mixture, contacting the resulting solution with heated water to remove the solvent and precipitating the vinyl chloride resin in water, and separating the precipitated vinyl chloride resin from water And a step of recovering the vinyl chloride resin.

Examples of the step of precipitating the vinyl chloride resin in the solution treatment include a method of adding a poor polyvinyl chloride solvent such as water instead of removing the solvent.
JP 2002-284920 A

  In Patent Document 1, in order to precipitate the vinyl chloride resin from the solvent, the pressure in the precipitation tank storing the solution from which the insoluble solid content has been removed is reduced, and the solvent is evaporated and removed by adding steam to the solution. By depositing a vinyl chloride resin in water, a slurry containing the precipitate is formed. At this time, by removing the solvent, the liquid level in the precipitation tank is lowered, so that the vinyl chloride resin contained in the solution adheres to the wall surface. Moreover, a trace amount vinyl chloride resin is contained in the solvent to evaporate, and this trace amount vinyl chloride resin adheres to the part which is not in contact with the solution of the wall surface of a precipitation tank. Once the vinyl chloride resin adheres to the wall surface of the precipitation tank, the attached vinyl chloride resin grows as a core, and a cluster (block) of vinyl chloride resin is generated on the wall surface of the precipitation tank. When this cluster of vinyl chloride resin grows to a certain size, it falls into the settling tank from the wall of the settling tank, leading to blockage of the discharge pump that discharges the slurry from the settling tank, blockage of piping on the upstream side of the discharge pump, etc. There was a thing.

  Further, even when the vinyl chloride resin is precipitated by adding a poor solvent without evaporating and removing the solvent, the above-described clusters of the vinyl chloride resin may be deposited on the wall of the precipitation tank by natural evaporation or the like. .

  Therefore, the above-described recovery method has a problem in that the above-mentioned blockage frequently occurs, which makes it difficult to operate continuously for a long time. In this case, it is necessary to circulate a high-temperature good solvent through the apparatus for recovering the vinyl chloride resin and perform an operation (hot solvent operation) for removing the vinyl chloride resin clusters in the precipitation tank or the like. Furthermore, it is necessary to clean the inside of the apparatus by disassembling the piping in the apparatus for recovering the vinyl chloride resin or disassembling the discharge pump.

  An object of the present invention is to provide an efficient vinyl chloride resin recovery method and recovery processing apparatus capable of continuous operation for a long period of time.

  The vinyl chloride resin recovery method of the present invention is a method of recovering vinyl chloride resin in waste containing vinyl chloride resin, wherein the vinyl chloride resin in waste is converted to vinyl chloride resin. A dissolving step in which the solvent is dissolved, a precipitation step in which a vinyl chloride resin is precipitated from the vinyl chloride resin solution to form a slurry containing precipitates, and the vinyl chloride resin is separated and recovered from the slurry. And a crushing step of crushing solid matter in the slurry between the precipitation step and the recovery step.

  According to this configuration, since the crushing step of crushing the solid matter contained in the slurry is provided between the precipitation step and the recovery step, a cluster (block body) of vinyl chloride resin is formed on the slurry formed in the precipitation step. ) Is contained, the occurrence of clogging by clusters is suppressed between the precipitation step and the recovery step. Therefore, it is possible to efficiently recover the vinyl chloride resin that can be operated continuously for a long time.

  Moreover, it is preferable that the said crushing process is arrange | positioned in-line from the said precipitation process to the said collection | recovery process. By being arranged in this way, it is not necessary to take a detour path for crushing solids in the slurry, which is more efficient.

  Moreover, it is preferable that the said precipitation process is a process which forms the slurry by which the said precipitate was disperse | distributed in water, volatilizing the said solvent by supplying steam to the said vinyl chloride resin solution. According to this configuration, precipitates can be generated more efficiently. Further, when steam is supplied, the glass transition temperature of the vinyl chloride resin is exceeded, so that the precipitated vinyl chloride resin is likely to adhere to the wall surface in the apparatus and the vinyl chloride resin cluster is likely to be generated. In such a case, the effects of the present invention are particularly exerted.

  Moreover, it is preferable that the said precipitation process is a process of forming the slurry by which the said deposit was disperse | distributed to the said poor solvent by supplying the poor solvent of the said vinyl chloride resin to the said vinyl chloride resin solution. . According to this configuration, clusters of vinyl chloride resin are unlikely to occur, and the long-term operation is inhibited from being inhibited by the clusters of vinyl chloride resin.

  Moreover, it is preferable that the said precipitation process is a process of forming the slurry by which the said precipitate was disperse | distributed to the said remaining solvent, removing the said solvent by heating the said vinyl chloride resin solution. According to this configuration, there is no need for an apparatus or the like for adding steam or the like, and deposition can be easily performed only by heating.

  Moreover, it is preferable to further provide a separation step of separating the vinyl chloride resin solution by removing insoluble matters that have not been dissolved between the dissolution step and the precipitation step. According to this structure, generation | occurrence | production of the obstruction | occlusion by an insoluble matter is suppressed. Accordingly, it is possible to efficiently recover the vinyl chloride resin that can be continuously operated for a longer period of time. In addition, the possibility of insoluble matters mixed in the recovered vinyl chloride resin is reduced.

  Moreover, it is preferable to further provide the liquid feeding process which sends the said slurry to a slurry storage tank between the said crushing process and the said collection | recovery process. According to this configuration, even if the slurry formed in the precipitation step includes a cluster of vinyl chloride resin, the slurry in which the cluster is crushed is fed. This eliminates the need for cleaning and enables efficient recovery of the vinyl chloride resin that can be operated continuously for a longer period of time.

  Moreover, it is preferable that the said solid substance is a lump (cluster) of the said vinyl chloride resin. The clusters of the vinyl chloride resin are formed on the wall surface of the precipitation tank in which the precipitation process is performed. If the clusters are mixed into the slurry, the clusters are likely to be clogged. The effect of the present invention is particularly exerted by crushing the cluster in the crushing step.

  The vinyl chloride resin recovery treatment apparatus of the present invention is an apparatus for recovering vinyl chloride resin in waste containing vinyl chloride resin, the solvent dissolving vinyl chloride resin and the waste And dissolving a vinyl chloride resin in the waste in the solvent, a dissolution tank for preparing a vinyl chloride resin solution, and a vinyl chloride resin from the vinyl chloride resin solution. A precipitation means for forming a slurry containing precipitates by precipitation; and a recovery means for separating and recovering the vinyl chloride resin from the slurry; and between the precipitation means and the recovery means, It further comprises crushing means for crushing the solid matter.

  According to this configuration, since the crushing means for crushing the solid matter in the slurry is provided between the precipitation means and the collection means, the slurry formed by the precipitation means contains a vinyl chloride resin cluster. However, it is crushed and the occurrence of clogging due to clusters is suppressed between the precipitation means and the collection means. Therefore, it is possible to realize an efficient vinyl chloride resin recovery treatment apparatus capable of continuous operation for a long time.

  According to the present invention, it is not necessary to clean the inside of the apparatus by disassembling the piping in the apparatus or disassembling the discharge pump in order to efficiently crush the clusters generated when the vinyl chloride resin is deposited. Further, it is possible to provide an efficient vinyl chloride resin recovery method and recovery processing apparatus capable of continuous operation for a long period of time.

  The vinyl chloride resin recovery method of the present invention is a method of recovering vinyl chloride resin in waste containing vinyl chloride resin, wherein the vinyl chloride resin in waste is converted to vinyl chloride resin. A dissolving step in which the solvent is dissolved, a precipitation step in which a vinyl chloride resin is precipitated from the vinyl chloride resin solution to form a slurry containing precipitates, and the vinyl chloride resin is separated and recovered from the slurry. And a recovery step, and a crushing step of crushing the solid matter in the slurry between the precipitation step and the recovery step.

  Below, one Embodiment of the collection | recovery method of the vinyl chloride-type resin of this invention is described based on FIG.

  FIG. 1 is a schematic view showing a processing apparatus 1 for carrying out the vinyl chloride resin recovery method of the present invention. The processing apparatus 1 includes a waste supply hopper 2, a dissolution tank 3, a filtration apparatus 4, a resin precipitation tank 5, a crushing apparatus 6, a discharge pump 7, a slurry storage tank 8, a centrifuge 9, and the like.

  First, the processing apparatus 1 performs the melt | dissolution process which dissolves the vinyl chloride-type resin in the waste containing a vinyl chloride-type resin in a solvent.

  First, the processing apparatus 1 supplies waste containing a vinyl chloride resin from the waste supply hopper 2 to the dissolution tank 3.

  The waste can be used without particular limitation as long as it contains a vinyl chloride resin, and a waste containing vinyl chloride resin as a main component is preferable. Specifically, for example, vinyl chloride resin pipe materials such as polyvinyl chloride pipes and polyvinyl chloride joints, vinyl chloride sheets such as agricultural vinyl chloride sheets and waterproof sheets, wallpaper base materials, covering materials for waste wires, and the like.

  In addition, it is preferable that the waste supplied to the dissolution tank 3 is cut into an appropriate size in advance in order to easily dissolve the vinyl chloride resin.

  Then, a solvent for dissolving the vinyl chloride resin (a good solvent for the vinyl chloride resin) is supplied from a solvent supply tank (not shown) to the dissolution tank 3.

  The solvent used in the present invention can be used without particular limitation as long as it is an organic solvent that dissolves the vinyl chloride resin. Specifically, aliphatic ketones such as acetone, methyl ethyl ketone and methyl isobutyl ketone, aromatic hydrocarbons such as benzene, toluene and xylene, cyclic ketones such as cyclohexanone, cyclic ethers such as tetrahydrofuran, γ-butyrolactone, etc. These cyclic esters and cyclic amides such as N-methylpyrrolidone can be used alone or in combination of two or more. Among these, in particular, methyl ethyl ketone and tetrahydrofuran can selectively dissolve the vinyl chloride resin, and since these boiling points are lower than the boiling point of water, when adding steam as described later to the solvent, The addition of steam is preferable because the solvent can be easily removed by volatilization.

  The supply amount of the solvent is preferably 200 to 800 parts by mass and more preferably 300 to 700 parts by mass with respect to 100 parts by mass of the vinyl chloride resin contained in the waste. When the supply amount of the solvent is too small, the viscosity of the solution becomes too high, and the insoluble matter is difficult to uniformly disperse in the solvent, and the filter of the filtration device 4 used for removing the insoluble matter, which will be described later, etc. Tends to be clogged, and when the supply amount is too large, the processing efficiency tends to decrease.

  The temperature of the solution is not particularly limited as long as the vinyl chloride resin is dissolved, but is preferably 120 ° C. or less in order to avoid unnecessary thermal history, and in order to increase the dissolution efficiency, It is preferable that it is 90 degreeC or more. Further, two or more kinds of vinyl chloride resins may be added to the solvent heated in advance, and after two or more kinds of vinyl chloride resins are added to the solvent before heating, the solvent is added. You may heat. In addition, in the case of the said heating, it is preferable to heat under pressure so that a solvent may not boil.

  The mixture of the waste containing the vinyl chloride resin in the dissolution tank 3 and the solvent in the dissolution tank 3 is stirred until the vinyl chloride resin contained in the waste is dissolved in the dissolution tank 3. Continue stirring with apparatus 11. As a result, a vinyl chloride resin solution in which insoluble matter is dispersed is obtained. In addition to the vinyl chloride resin, the resulting solution may contain a component that dissolves in a solvent contained in the waste, such as a plasticizer.

  The stirrer 11 is not particularly limited as long as the mixture of waste and solvent can be stirred in the dissolution tank 3, and examples thereof include a stirrer equipped with a stirring blade and the like.

  Next, it is preferable that the processing apparatus 1 performs the separation process which isolate | separates an insoluble matter. The method of a separation process is not specifically limited, For example, each is separated by the specific gravity difference of a solution and an insoluble matter by carrying out the filtration method which isolate | separates an insoluble matter using filtration apparatuses 4, such as a filter, and settling down. In addition, a precipitation method in which only the supernatant solution is removed by suction using a pump or the like, a centrifugal separation method such as centrifugal dehydration, or a combination thereof is appropriately selected as desired.

  In the present embodiment, a method using the filtration device 4 will be described as an example. As shown in FIG. 1, this method is performed by passing a vinyl chloride resin solution in which insoluble matters are dispersed in a dissolution tank 3 through a filtration device 4. As a result, a vinyl chloride resin solution from which insoluble matter is separated is obtained.

  As the filtration device 4, various known filtration devices that can filter insoluble matters are used without particular limitation. The filter attached to the filtration device may be composed of only one filter or may be a combination of a plurality of filters.

  As a filter used at this time, a metal mesh filter having an opening (mesh) of 50 to 150 μm can efficiently separate the vinyl chloride resin solution and the insoluble matter. preferable. If the mesh opening is too small, clogging tends to occur and the processing efficiency tends to decrease. If it is too large, a large amount of insoluble matter tends to be mixed in the resulting vinyl chloride resin solution.

  Further, a scraper that scrapes insoluble matter deposited on the surface of the filter may be provided. By doing so, clogging of the filter due to accumulation of insoluble matter on the surface of the filter can be suppressed, and the number of times of cleaning of the filter can be reduced. Therefore, continuous operation for a longer period is possible.

  Next, the processing apparatus 1 supplies the vinyl chloride resin solution obtained by the above-described dissolution step and separation step, from which the insoluble matter has been separated, to the resin precipitation tank 5, and from the vinyl chloride resin solution to the vinyl chloride resin. A precipitation step for precipitating is performed.

  The precipitation method in the precipitation step is not particularly limited, and is a method in which the vinyl chloride resin solution is heated to volatilize the solvent so as to be in a supersaturated state, and the vinyl chloride resin solution is stirred into the vinyl chloride resin solution. A method of reducing the solubility by adding a poor solvent (for example, water) to the resin based on precipitation, a method of volatilizing the solvent by supplying steam to the vinyl chloride resin solution, and the like are appropriately selected. .

  When using the method of adding a poor solvent under stirring, the shape of the precipitated vinyl chloride resin is fine and uniform, which is preferable. In particular, when the boiling point of the solvent is lower than that of water, the method of supplying steam to the vinyl chloride resin solution is preferable because the solvent can be volatilized by adding steam.

  Specifically, the method of supplying steam to the vinyl chloride resin solution is performed as follows.

  First, the vinyl chloride resin solution and steam are brought into contact with each other by introducing steam into the resin precipitation tank 5. By doing so, the solubility of the vinyl chloride resin in the solvent is partially abruptly reduced, and the solvent in the solution is volatilized by the steam temperature. According to this method, the introduced steam volatilizes the solvent and is converted into liquid water in the container, and gradually increases the amount thereof, so that the vinyl chloride resin is gradually precipitated in water. . Finally, a slurry in which a vinyl chloride resin is dispersed in water is obtained. In this case, the deposition rate can be adjusted by controlling the temperature of the steam.

  Moreover, when volatilizing a solvent, it is preferable to carry out stirring with the stirring apparatus 12 with which the resin precipitation tank 5 was equipped. This is because by introducing steam while stirring, the vinyl chloride resin can be precipitated in the form of fine particles, and the particle diameter can be controlled by controlling the number of rotations of stirring. The stirring device 12 is not particularly limited as long as the slurry in the resin precipitation tank 5 can be stirred, and examples thereof include a stirring device provided with stirring blades and the like.

  In the recovery method of the present invention, an additive for vinyl chloride resin may be added in the dissolution step or the precipitation step. Thus, by adding the additive and the like, a vinyl chloride resin composition in which the additive is uniformly dispersed can be obtained.

  Next, the processing apparatus 1 performs a liquid feeding step of feeding the slurry to the slurry storage tank 8 by the discharge pump 7, but before that, in a pipe communicating the resin precipitation tank 5 and the slurry storage tank 8, A crushing step of crushing solids contained in the slurry is performed.

  The crushing method in a crushing process is not specifically limited, The method of crushing with the crushing apparatus 6 provided in the piping which connects the resin precipitation tank 5 and the slurry storage tank 8, The method of using the discharge pump with a crushing function, or those A combination method or the like is appropriately selected as desired. Moreover, the crushing method in the crushing process crushes the vinyl chloride resin clusters contained in the slurry formed in the precipitation process.

  As the crushing device 6, known various crushers capable of crushing clusters contained in the slurry are used without particular limitation. For example, human waste treatment, waste treatment, wastewater treatment in a chemical product factory, wastewater treatment in a food processing factory, a yarn mill Pulverizers used for wastewater treatment, general industrial waste treatment, and the like. Further, as the crusher, an inline crusher installed in-line on a pipe connecting the resin precipitation tank 5 and the slurry storage tank 8 is preferable, and a biaxial crusher is preferable. Examples of commercially available products include Muffin / Monster inline type (30004T-1208) manufactured by Sakai Kogyo Co., Ltd. Moreover, the crushing apparatus 6 may be provided independently in piping which connects the resin precipitation tank 5 and the slurry storage tank 8, and multiple may be provided.

  As a discharge pump with a crushing function, it can be used without any limitation as long as the crushing function can be demonstrated and the slurry can be fed. For example, human waste treatment, sewage treatment, waste volume reduction treatment, chemical production plant Discharge pumps with a crushing function used for wastewater treatment of food processing, wastewater treatment of food processing plants, and the like. Moreover, as a commercial item, the disintegrator made from Zenoa Co., Ltd., etc. are mentioned, for example.

  By performing the crushing step, it is possible to suppress the occurrence of clogging due to a pipe of the resin precipitation tank 5 and the slurry storage tank 8 and the discharge pump 7 for performing the liquid feeding step due to a vinyl chloride resin cluster or the like.

  Moreover, when providing the crushing device 6 in the piping which connects the resin precipitation tank 5 and the slurry storage tank 8, the discharge pump 7 can be used without particular limitation as long as the slurry can be fed, and does not have a crushing function. Good.

  Next, the processing apparatus 1 performs a recovery step of separating and recovering the vinyl chloride resin from the slurry sent to the slurry storage tank 8, but before that, a crushed material separation step of separating the crushed material of the cluster is performed. It is preferable. By performing the crushed material separation step, the quality (for example, particle size and properties) of the finally obtained vinyl chloride resin can be kept constant.

  The method of the crushed material separation step is not particularly limited. Specifically, for example, there is a method of separating clusters crushed by the crushing device 6 using the filter 13 provided in the slurry storage tank 8.

  As the filter 13, it is preferable to use a mesh filter having an opening of 1 to 7 mm, preferably 3 mm or more. If it is 1 mm or less, there is a possibility that even the vinyl chloride resin as a product may be collected by a filter, and the processing efficiency may be lowered. Moreover, there exists a possibility that a big cluster may mix in a product as it is 7 mm or more. In addition, the position where the filter 13 as the crushed material separating means is installed is not limited to the slurry storage tank 8, and may be any position as long as it is a subsequent stage of the crushing device 6. In the present embodiment, by providing the filter 13 in the slurry storage tank 8, there is an advantage that separation of cluster crushed materials and removal of clusters accumulated on the filter 13 can be easily performed. In addition, it is not essential to provide the crushed material separation means (the filter 13 in this embodiment).

  In the recovery step, the slurry from which the crushed material of the clusters of a predetermined size or larger has been removed is separated into a vinyl chloride resin and water. In the present embodiment, a method using a centrifuge will be described as an example.

  As described above, the processing apparatus 1 allows the slurry that has passed through the crushing apparatus 6 to pass through the filter 13 provided in the slurry storage tank 8, thereby separating a relatively large crushed material in the slurry from the slurry. Furthermore, water is removed from the slurry obtained after the separation by a centrifuge. As a result, a vinyl chloride resin is obtained from the slurry.

  The centrifuge 9 can be used without particular limitation as long as the slurry can be separated into water and vinyl chloride resin.

  As described above, the vinyl chloride resin can be recovered continuously for a long period of time by providing a crushing step between the precipitation step and the recovery step.

  In addition, the present embodiment may further include the following steps.

  In the recovery method of the present invention, a drying step is usually performed after the recovery step. By passing through the drying step, a more dried vinyl chloride resin can be obtained.

  The method of the drying process is not particularly limited. For example, drying by a continuous or batch type hot air dryer, oven dryer, fluid dryer, air dryer, rotary kiln dryer, spray dryer, etc. Can be mentioned.

  Moreover, the collection | recovery method of this invention may perform the washing | cleaning process of wash | cleaning the waste containing a vinyl chloride resin before a melt | dissolution process. For example, by washing waste with water at room temperature, it is possible to remove previously weak soil or the like, and reduce insoluble matter in the dissolution process.

  In the recovery method of the present invention, a magnetic treatment step may be performed before the dissolution step. For example, before the washing step, a magnetic treatment step can be performed with a magnet or the like, and metals can be removed from the waste in advance.

  In the present embodiment, the slurry storage tank 8 is installed after the resin precipitation tank 5 and the slurry can be temporarily stored. However, the present invention is not limited to this, and a centrifugal separator that is a recovery device after the resin precipitation tank 5 is used. 9 may be installed. Even in this case, a discharge pump 7 or the like is installed between the resin precipitation tank 5 and the centrifugal separator 9.

  Hereinafter, the present invention will be specifically described with reference to examples. In addition, this invention is not limited to the form of a present Example at all. An embodiment using the processing apparatus 1 shown in FIG. 1 will be described.

(Example)
First, 7t of waste containing vinyl chloride resin (amount of vinyl chloride resin in the waste of 5t) was charged into the dissolution tank 3 of 40 m ³ from the waste supply hopper 2. Next, 20 t of methyl ethyl ketone was charged into the dissolution tank 3 from a solvent supply tank (not shown).

  While stirring the mixture in the dissolution tank 3 with the stirring device 11 provided in the dissolution tank 3, the pressure in the dissolution tank 3 is set to 0.3 MPa, the methyl ethyl ketone is heated to 100 ° C., and is stirred as it is for 10 minutes. The vinyl chloride resin was dissolved to obtain a vinyl chloride resin solution in which insoluble matter was dispersed.

  The dissolution tank 3 is returned to atmospheric pressure, the vinyl chloride resin solution in which the insoluble matter is dispersed is passed through a filtration device 4 equipped with a metal mesh filter having an opening of 100 μm, and the insoluble matter is recovered and filtered. The liquid was transferred to the resin precipitation tank 5.

  By introducing 2Ot of steam at 110 ° C. into the resin precipitation tank 5 for 60 minutes, methyl ethyl ketone was volatilized and removed while precipitating vinyl chloride resin from the solution, and finally almost all methyl ethyl ketone was removed. The methyl ethyl ketone that has been volatilized and removed is returned to the dissolution tank 3 and reused as a solvent for dissolving the vinyl chloride resin.

  The vinyl chloride resin in the resin precipitation tank 5 was present in a slurry state dispersed in water.

  This slurry was transferred to the slurry storage tank 8. At that time, the clusters contained in the slurry were crushed by a crushing device 6 provided in a pipe communicating the resin precipitation tank 5 and the slurry storage tank 8.

  The slurry transferred to the slurry storage tank 8 passes through the filter 13 provided in the slurry storage tank 8 so that the crushed clusters are separated. Removed. By doing so, a vinyl chloride resin was obtained.

  Although a total of 180 recovery processes were performed, the HOT solvent operation in which methyl ethyl ketone (HOT solvent) heated to the 74th recovery process flows through a pipe that connects the resin precipitation tank 5 and the slurry storage tank 8 to each other. Went.

(Comparative example)
It is the same as that of an Example except not providing the crushing apparatus 6 in the piping which connects the resin precipitation tank 5 and the slurry storage tank 8. FIG.

  Although a total of 256 recovery processes were performed, the methyl ethyl ketone (HOT solvent) heated to a high temperature was connected to the resin deposition tank 5 and the slurry storage tank 8 during the 32nd, 95th, and 158th recovery processes. The HOT solvent operation which flows into the piping to perform was performed.

  FIG. 2 is a graph showing the relationship between the number of treatments (batch times) in the treatment apparatus 1 and the number of discharge pump / pipe washings. FIG. 2A shows a comparative example, and FIG. 2B shows an example. Further, the horizontal axis indicates the number of batches, and the vertical axis indicates the number of times of discharging pump / pipe cleaning.

  As can be seen from FIG. 2, in the embodiment provided with a crushing step between the precipitation step and the recovery step, a pipe that communicates the resin precipitation tank 5 and the slurry storage tank 8 even when operated continuously for a long time. In addition, the discharge pump 7 is less likely to be blocked by a vinyl chloride resin cluster or the like, and the discharge pump / pipe cleaning frequency is small.

  On the other hand, in the comparative example that does not include the crushing process between the precipitation process and the recovery process, immediately after the HOT solvent operation is performed, the number of times of drain pump / pipe cleaning does not increase, but the operation time As the number increased, the number of discharge pump / pipe cleaning increased.

It is the schematic which shows the processing apparatus 1 for enforcing the collection | recovery method of the vinyl chloride-type resin of this invention. It is a graph which shows the relationship between the processing frequency (batch frequency) in the processing apparatus 1, and the discharge pump and piping washing frequency.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Processing apparatus 2 Waste supply hopper 3 Dissolution tank 4 Filtration apparatus 5 Resin precipitation tank 6 Crushing apparatus 7 Discharge pump 8 Slurry storage tank 9 Centrifugal apparatus 11,12 Agitation apparatus 13 Filter

Claims (9)

A method of recovering vinyl chloride resin in waste containing vinyl chloride resin,
Forming a slurry containing precipitates by dissolving the vinyl chloride resin in the waste in a solvent for dissolving the vinyl chloride resin and precipitating the vinyl chloride resin from the vinyl chloride resin solution And a recovery step of separating and recovering the vinyl chloride resin from the slurry,
A vinyl chloride resin recovery method, further comprising a crushing step of crushing solids in the slurry between the precipitation step and the recovery step.   The method for recovering a vinyl chloride resin according to claim 1, wherein the crushing step is arranged in-line from the precipitation step to the recovery step.   The said precipitation process is a process of forming the slurry by which the said deposit was disperse | distributed in water, volatilizing the said solvent by supplying steam to the said vinyl chloride resin solution. The method for recovering the vinyl chloride resin according to the description.   The said precipitation process is a process of forming the slurry by which the said deposit was disperse | distributed to the said poor solvent by supplying the poor solvent of the said vinyl chloride resin to the said vinyl chloride resin solution. Item 3. A method for recovering a vinyl chloride resin according to Item 2.   The said precipitation process is a process of forming the slurry by which the said precipitate was disperse | distributed to the said remaining solvent, removing the said solvent by heating the said vinyl chloride resin solution. 4. A method for recovering a vinyl chloride resin as described in 1.   The separation process according to any one of claims 1 to 5, further comprising a separation step of separating the vinyl chloride resin solution by removing insoluble matters that have not been dissolved between the dissolution step and the precipitation step. Collection method of vinyl chloride resin.   The method for recovering a vinyl chloride resin according to any one of claims 1 to 6, further comprising a liquid feeding step of feeding the slurry to a slurry storage tank between the crushing step and the collecting step.   The method for recovering a vinyl chloride resin according to any one of claims 1 to 7, wherein the solid is a lump of the vinyl chloride resin. An apparatus for recovering vinyl chloride resin in waste containing vinyl chloride resin,
A dissolution tank for preparing a vinyl chloride resin solution by mixing the waste with the solvent for dissolving the vinyl chloride resin and dissolving the vinyl chloride resin in the waste in the solvent; A precipitation means for forming a slurry containing precipitates by precipitating a vinyl chloride resin from the vinyl chloride resin solution; and a recovery means for separating and recovering the vinyl chloride resin from the slurry,
A vinyl chloride resin recovery processing apparatus, further comprising a crushing means for crushing solid matter in the slurry between the precipitation means and the recovery means.

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