JP2001232327A - Method of dissolving and treating foamed polystyrene waste material and liquid for dissolving the foamed polystyrene waste material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of dissolving and treating a foamed polystyrene waste material, by which the danger of flashing of a solvent can be completely avoided and in which the solvent is maintained at ordinary temperature at which the solvent exhibits the dissolving function by utilizing the heat of the chemical reaction without vaporizing the solvent, the foamed polystyrene waste material can be dissolved in a short time with a small amount of energy, the dissolved polystyrene can be reused as heavy oil A and the energy required for reducing the volume of the foamed polystyrene waste material is small, and further which is excellent in economical efficiency, and to provide a liquid for dissolving the foamed polystyrene waste material. SOLUTION: An agent for dissolving the foamed polystyrene is a mixed liquid containing water as a major ingredient and citric acid, toluene and an alcohol as minor ingredients, which is obtained by injecting toluene and the alcohol into an aqueous solution of citric, in which water is contained as a major ingredient and then mixing the resulting liquid. The foamed polystyrene waste material is dissolved by using the agent mentioned above.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention can completely prevent the danger of ignition of a solvent, and can maintain a room temperature at which a solvent is not volatilized by using heat of chemical reaction and exerts a dissolving function. Dissolving styrofoam waste material in a short period of time, and it can be reused as heavy oil A after dissolving, and the energy required for volume reduction of the styrofoam waste material is small and economical. The present invention relates to a method and a solution of waste polystyrene foam.

[0002]

2. Description of the Related Art In recent years, the demand for expanded polystyrene produced by radical polymerization of a styrene monomer has been increasing. For packing home appliances, OA equipment, and the like, a molded article of Styrofoam is often used. In addition, it is widely used as a buffer material for glass products, a container for keeping food warm, and the like. The amount of styrofoam waste discharged from ordinary households is also considerable. For this reason, there is a problem of efficient treatment of the styrofoam waste. Plastic waste generates toxic gas and graphite when burned, causing environmental problems, and does not decompose when buried in the ground. Among them,
Styrofoam resin is light, bulky and extremely difficult to treat.

In a supermarket, an agricultural cooperative, a wholesale market, and the like, since a large amount of styrofoam waste is discharged, a volume reduction process and a recycling process of the styrofoam waste are performed. In addition, with the recent public awareness of resource saving, there has been a movement to treat styrofoam waste discharged from general households in supermarkets and the like.

[0004] When recovering and recycling, there is a problem that the volume per unit weight is very large, so that it is difficult to recover without reducing the volume of the waste material. In recovering the styrofoam waste material, a method in which the waste material is cut into small pieces, heated and melted to reduce the volume, solidified, and pelletized is often used. No. 92429, and the like. As a method of heating and compressing waste materials, Japanese Patent Laid-Open No. 4-198516 discloses a method.
Japanese Unexamined Patent Application Publication No. 6-238688 and Japanese Unexamined Patent Application Publication No. 6-238688 disclose a method of utilizing waste heating oil or heating oil.
No. 14, JP-A-4-219186, JP-A-6
Japanese Patent Application Laid-Open Nos. 5-26832 and 5-2732 disclose methods of utilizing frictional heat generation.
It is described in, for example, Japanese Patent Publication No. 1655. However, if the volume reduction of the styrofoam waste material is performed by heat treatment, there is a disadvantage that the effective components that can be originally recovered during the volume reduction treatment are gasified as odorous and volatile gases. Further, since it is not preferable from the viewpoint of safety and hygiene to reduce the volume of the styrofoam waste material by heat treatment, a technique for dissolving the styrofoam waste material with a solvent has attracted attention.

[0005] When a waste material is recovered using a solvent, a method is used in which the styrene foam waste material is liquefied and recovered with an aromatic solvent, a ketone solvent or the like which dissolves the styrene foam waste material, and then the solvent is evaporated and separated. Of these, methods using an aromatic solvent are described in JP-A-5-59212, JP-A-6-143284, JP-A-6-143285, and JP-A-6-237.
No. 53, JP-A-6-316646, JP-A-7
JP-A-97475, JP-A-7-113089, and the like. A method using a chlorine-based organic solvent is disclosed in JP-A-7-26057 and the like, and an example of a processing apparatus and method using a solvent is disclosed in JP-A-5-285467 and the like.
A method of immersing in a W emulsion is disclosed in
No. 46, for example. Hereinafter, this will be described in more detail.

Japanese Patent Application Laid-Open No. 07-041772 proposes the use of an aromatic hydrocarbon oil or a hydrocarbon oil mainly composed of an aromatic hydrocarbon oil as a solvent for dissolving styrofoam waste. Pyrolysis of styrene resin waste produces aromatic hydrocarbon oil.If this is mixed with styrofoam resin waste as a solvent, the styrofoam resin foams out and dissolves, and finally dissolves in the solvent. It clearly states that no residue will be left.

As a solvent for dissolving styrofoam waste as disclosed in JP-A-07-097475, styrofoam waste can be prepared by using paraffinic hydrocarbons such as hexane, heptane and octane, methyl ethyl ketone, diethyl ketone, methyl-n-propyl ketone and hexanone. And ketones such as benzene, toluene, and xylene. In particular, the use of dipentene (2.8 (9) -paramentadiene) has been proposed as a monoterpene-based hydrocarbon. After dissolving the styrofoam waste material with a solvent, it is recovered as a resin, and this resin is reused as a molded product.

As a solvent for dissolving styrofoam waste material disclosed in JP-A-07-324192, an aromatic hydrocarbon oil or a hydrocarbon oil containing an aromatic hydrocarbon oil as a main component is preferable, and a styrene monomer solution is particularly preferable. Preferably, when the styrene-based resin waste is thermally decomposed, a styrene monomer-based hydrocarbon oil is generated in a low-temperature fraction, and this can be recycled as a solvent.

As a solvent for dissolving the styrofoam waste shown in JP-A-9-157435, a volume reducing agent for reducing the volume of the styrofoam waste,
20 to 90% by mass of a solvent that can easily dissolve foamed styrene resins such as aromatics, ketones, esters, ethers, unsaturated aliphatic hydrocarbons, and cycloaliphatic hydrocarbons, and normal paraffinic and isoparaffinic solvents It has been proposed to use a mixed solvent obtained by uniformly mixing a solvent selected from the group consisting of aliphatic hydrocarbons and alcohols.

As a solvent for dissolving styrofoam waste material disclosed in JP-A-11-199702, flame-retardant organic solvents (methylene chloride, ethylene dichloride, ethylene trichloride, ethylene dichloride, propylene chloride, methyl chloride, tetrachloroethane, perchloroethane) Halogen-substituted paraffinic saturated hydrocarbons, olefinic unsaturated hydrocarbons and aromatic hydrocarbons such as ethylene and monochlorobenzene, and organic peroxides (benzoyl peroxide, chlorobenzoyl peroxide, dichlorobenzoyl peroxide) Tert-butyl hydroperoxide, diisopropylbenzene hydroperoxide, dicumyl peroxide, tert-butyl peroxyisobutyrate, tert-butyl peroxyisopropyl carbonate). And to the ground polystyrene foam powder,
The styrene foam volume-reducing liquid is dissolved by coating or spraying. The ignition dissolution measures are to be performed twice in each of the accelerated dissolution solution of the polystyrene foam and both the pulverization step and the dissolution step.

Japanese Patent Application Laid-Open No. H11-012388 proposes the use of an organic chlorine-based solvent (dichloromethane) as a solvent for dissolving styrofoam waste.

[0012]

The method of heating, melting, and solidifying waste materials involves a large amount of energy consumption.
Not an economical method. Further, a method of dissolving waste materials in a solvent to obtain a solution, evaporating and separating the solvent in the solution, and separating and solidifying the recovered styrofoam resin requires a large amount of heat energy particularly in the step of distilling off the solvent. Requires a long time for processing. In the step of grinding the polystyrene foam mass, static electricity generated by mechanical shock and friction, etc., causes the polystyrene foam powder to explode in dust, or ignites an organic solvent that attempts to dissolve the polystyrene foam powder, There was constant danger. Among the above-listed inventions, the one that avoided the danger of ignition of the organic solvent was only a solvent for dissolving styrofoam waste as disclosed in JP-A-11-199702.

According to the present invention, the danger of ignition of the solvent can be completely avoided, and the solvent can be maintained at room temperature without using the heat of chemical reaction to volatilize the solvent and exhibit the dissolving function. A method for dissolving styrofoam waste and a method for dissolving styrofoam waste, which are capable of dissolving the styrofoam waste, and capable of being reused as heavy oil A after dissolution, requiring less energy for reducing the volume of the styrofoam waste, and having excellent economic efficiency. It is intended to provide a solution of

[0014]

The above object is achieved by the following means. (1) A method for dissolving styrofoam waste, comprising reducing the volume of styrofoam waste with a styrofoam volume reducing agent comprising a mixture of water as a major component and citric acid, toluene and alcohol as minor components. (2) A polystyrene foam reducing agent composed of a mixture of water as a major component and a mixture of water and a small amount of citric acid, toluene and alcohol by jet mixing of toluene and alcohol in a citric acid aqueous solution. A method for dissolving styrofoam waste, characterized by reducing the volume of the styrofoam waste. (3) A solution of styrofoam waste material comprising a mixture of water as a major component and citric acid, toluene and alcohol as minor components. (4) Styrofoam waste material characterized in that water is used as a major component, and toluene and alcohol are injected and mixed in a citric acid aqueous solution to form a mixture containing water as a major component and citric acid, toluene and alcohol as minor components. Solution.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first stainless steel storage tank 1 stores tap water (not shown), and a citric acid stored in a stainless steel citric acid storage tank 2 is opened by opening a gate valve 3. 1 and at that time, while watching the level meter, water and citric acid were mixed in a volume ratio of 5 to 7
The mixture is adjusted to 1.5 and stirred by the stirring blade 4 to store the citric acid aqueous solution in the storage tank 1. The citric acid aqueous solution has no ignitability at all. Further, toluene and isopropyl alcohol (2-propanol) are stored in the second stainless steel storage tank 5 via the lid 5a so as to have a volume ratio of 1: 1. Since the mixture of toluene and alcohol is ignitable, it is preferable that the storage tank 5 is provided with a cooling device (not shown) capable of avoiding explosion protection due to abnormal heating of the storage tank 5 due to solar heat in summer and maintaining the temperature at room temperature. Ethyl acetate, butyl acetate, and butyl, which are the same aromatic hydrocarbons as toluene, have a low solubility in styrene foam and are not practical. Benzene, xylene, etc. have a high dissolving capacity for styrofoam like toluene, but they are not friendly to the global environment because they have strong toxicity such as carcinogenicity compared to toluene, and greatly impair the safety of the human body. It has been excluded in the present invention. t-Butyl alcohol can be used. Then, before the first processing of the styrofoam waste material, a preparation switch (not shown) is turned on. Thereby, the automatic valve 6 is opened, the pump 7 is started, and the citric acid aqueous solution stored in the storage tank 1 is fed into the dissolution tank 9 made of stainless steel via the feed pipe 8. The dissolution tank 9 is, for example, 2.5
Approximately 1 ton of styrofoam waste material (20 trucks) with a tank volume of m ³ can be processed. When the citric acid aqueous solution occupies approximately half the volume of the dissolution tank 9, the pump 7 stops driving. Subsequently, the compressor 10 is driven to feed high-pressure air through the pipe 11 to the nozzle pipe 12 having a myriad of pinholes provided at the bottom of the storage tank 5. The mixed solution of toluene and alcohol stored in 5 vaporizes and is fed via a pipe 13 to a nozzle pipe 14 having a myriad of pinholes provided at the bottom in a dissolution tank 9. For this reason, the mixed gas of toluene and alcohol supplied to the nozzle tube 14 is sprayed as fine bubbles from the nozzle tube 14 and dispersed in the citric acid aqueous solution. The microbubbles promote the dispersion of the mixed gas of toluene and alcohol into the aqueous citric acid solution quickly and effectively. The alcohol dissolves in the aqueous citric acid solution while the fine bubbles are dispersed in the aqueous citric acid solution.
Toluene is finely dispersed in the aqueous citric acid solution while fine bubbles are dispersed in the aqueous citric acid solution. The bubbles of toluene and alcohol injected from the pinhole of the nozzle tube 14 are:
Immediately and sufficiently mixed with citric acid aqueous solution and loses ignitability. The motor 1 is located above the nozzle tube 14.
The spiral wings 16 rotated by 5 are provided, and the partition plate 17 is further provided thereon. Therefore, the styrene foam dissolving liquid in which fine particulate liquid in which toluene and alcohol are mixed in an aqueous citric acid solution is dispersed is used as the partition plate 17. And convection in opposite directions. Thus, convection in the styrene foam solution in the dissolution tank 9 is ensured in the tank 9. The driving of the compressor 10 is performed only when the polystyrene foam is dissolved. When the operation of the compressor 10 is stopped, blue toluene is separated into an upper layer, and a colorless aqueous solution in which alcohol and citric acid are dissolved is separated into a lower layer. When the compressor 10 is driven, convection occurs and blue toluene is finely and sufficiently dispersed in a colorless aqueous solution in which alcohol and citric acid are dissolved.

When the lid 19 of the hopper 18 made of stainless steel is opened and the styrofoam waste material S is put in, and the lid 19 is closed, the automatic valve 20 is opened and the pump 21 is started to activate the tank 1.
The citric acid aqueous solution stored in the hopper 18 is supplied to the spray nozzle 23 provided on the inner wall of the hopper 18 via the pipe 22, and the motor 24 is activated with a delay of 2 to 3 seconds, and
The rotary cutter 25 provided at the bottom of the inside is configured to rotate. The styrofoam waste S put into the hopper 18 is charged with static electricity when it is cut into chips by the rotary cutter 25 and thus has a self-igniting property when it is finely divided like dust. No self-ignition due to static electricity is caused by the shower, and the tip is safely cut into chips by the rotary cutter 25. The styrofoam waste material is cut into chips by a rotary cutter 25, turns in the hopper 18, generates centrifugal force, is discharged to the entrance of the conveyor case 26, is conveyed by the conveyor 27, and enters the dissolution tank 9 made of stainless steel. The above citric acid aqueous solution is supplied to the conveyor case 26.
The liquid is collected from the upper surface of the dissolving tank 9 into the tank through a collecting pipe 29 by a pump 28. Note that a configuration may be employed in which the styrofoam waste material is directly cut into the dissolving tank 9 as it is without being cut into chips.

As described above, since the styrene foam solution in which toluene is sufficiently dispersed and mixed in the aqueous solution in which citric acid and alcohol are dissolved is convected along the upper and lower surfaces of the partition plate 17, the styrene foam introduced into the dissolution tank 9 is used. Waste material S
Is instantaneously dissolved by the styrene foam solution.
Styrofoam is dissolved by toluene, but the presence of citric acid and alcohol causes the dissolution action to be more pronounced than normal. Since citric acid and alcohol can exist as an aqueous solution without being separated from water, a styrene foam solution in which toluene is sufficiently finely dispersed and mixed,
It is ensured that the polystyrene foam can be sufficiently contacted with the toluene for dissolving the polystyrene foam, and thereby a remarkable dissolving action occurs. The heat of dissolution (heat of chemical reaction) heats the styrofoam solution at room temperature, so that the solvent is not volatilized and the dissolving function can be exhibited, thereby increasing the dissolution rate. Although toluene does not dissolve in water, it is sufficiently finely dispersed by pinhole injection and stirring. Since citric acid and alcohol can exist as an aqueous solution, good contact between citric acid and alcohol with sufficiently finely dispersed toluene in dissolution tank 9 can be easily achieved. When the amount of styrene foam to be dissolved is promoted, the dissolved concentration increases. As the amount of styrene foam dissolved increases, the concentration and viscosity of the styrene resin in the dissolving solution increase, and the styrene foam becomes jelly-like at the limit of the dissolving ability.

As described above, when styrene foam having the same weight as the styrene foam solution is dissolved, the gate valve 29 is opened and collected in a temporary storage tank (not shown), neutralized by adding a neutralizing agent (alkali), and not shown. Reuse it as fuel oil A at the fuel oil conversion facility.

When the treated liquid is extracted from the dissolution tank 9, the process is started again from the beginning. That is, a solution of styrofoam composed of water, citric acid, toluene and alcohol is stored in the dissolution tank 9, and the styrofoam waste is put into the hopper 18 to shower the citric acid aqueous solution.

[0020]

Example 1 A 100 cc foamed polystyrene solution in which water, toluene, and isopropyl alcohol (2-propanol) were adjusted to a volume ratio of 7: 1.5: 1.5 was mixed with a foamed polystyrene foam having the same volume as the solution in about 3 hours in about 5 hours. At last one part could be dissolved.

[0021]

Example 2 Water, toluene and citric acid were mixed in a volume ratio of 7
100cc styrene foam solution adjusted to 1.5 to 1.5
The result was almost equivalent to that of Example 1.

[0022]

Example 3 Water, citric acid, toluene and isopropyl alcohol were adjusted to a volume ratio of 7: 1.5: 0.75: 0.75.
The styrofoam solution of 00 cc was able to completely dissolve about twice the volume of styrofoam in 1 minute. This styrene foam solution was able to completely dissolve styrofoam having substantially the same weight as the styrene foam solution. That is, about 15 volumes of the styrene foam solution
4 times the volume of Styrofoam could be dissolved. Compared with the above Examples 1 and 2, the styrene foam solution has citric acid and isopropyl alcohol as an aqueous solution and has a high dissolving ability by remarkably reacting with the styrene foam in contact with toluene. I understand.

[0023]

According to the present invention, the dissolved styrene resin phase contains citric acid, toluene and alcohol,
Since water is a major component, the danger of ignition of the solvent can be completely avoided. The present invention makes it possible to maintain the dissolving solution composed of water of the major component, citric acid, toluene and alcohol of the minor components at room temperature by utilizing the heat of chemical reaction, and to enhance the dissolving ability for dissolving the styrofoam waste material. It is possible to use it with less energy and is more economical. In addition, the present invention dissolves the styrene resin phase, which contains citric acid, toluene and alcohol, but has a large amount of water, so it is compared with the case of dissolving the foamed styrene waste material with a conventional aromatic hydrocarbon such as toluene. Thus, the total amount of toluene contained in the solution is overwhelmingly small, it can be reused as heavy oil A after dissolution, and the dissolution rate is extremely high.

[Brief description of the drawings]

FIG. 1 is a schematic overall view of an apparatus for carrying out the present invention.

[Explanation of symbols]

1 ... storage tank, 2 ... citric acid storage tank, 3
... gate valve, 4 ... stirring blade, 5 ... storage tank,
5a: lid, 6: automatic valve, 7: pump, 8.
..Feed pipe, 9 dissolution tank, 10 compressor, 11 pipe, 12 nozzle pipe, 13 pipe
・ Tube, 14 ・ ・ ・ Nozzle tube, 15 ・ ・ ・ Motor, 16 ・
..Spiral wings, 17 ... partition plates, 18 ... hoppers,
19 ... lid, 20 ... automatic valve, 21 ... pump,
22 ... tube, 23 ... sprayer, 24 ... motor,
25 ... rotating cutter, 26 ... conveyor case,
27 ... conveyor, 28 ... pump, 29 ... collection pipe, 30 ... gate valve, S ... styrene foam waste material,

Continuation of the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (reference) C10L 1/12 C10L 1/18 C 1/16 Z 1/18 C08L 25:00 B09B 3/00 304P // C08L 25: 00 ZAB

Claims (4)

[Claims] 1. A method for dissolving styrofoam waste, comprising reducing the volume of styrofoam waste with a styrofoam volume reducing agent comprising a mixture of water as a major component and citric acid, toluene and alcohol as minor components. . 2. A polystyrene foam comprising a mixture of water and a mixture of water and a small amount of citric acid, toluene and alcohol by jetting and mixing toluene and alcohol in a citric acid aqueous solution. A method for dissolving styrofoam waste material, comprising reducing the volume of styrofoam waste material with an agent. 3. A styrene foam waste material solution comprising a mixture of water as a major component and citric acid, toluene and alcohol as minor components. 4. A mixed solution comprising water as a major component and jetting and mixing toluene and alcohol in a citric acid aqueous solution to form water as a major component and citric acid, toluene and alcohol as minor components. Solution of styrofoam waste.