JP3726211B2 - Oily processing method of styrene resin waste material - Google Patents

Description

[0001]
【Technical field】
The present invention relates to a method for oily treatment of styrene resin waste material. In particular, the invention is suitable for oil-treating foamed PS waste material.
[0002]
Here, a foamed PS waste material will be described as an example of the PS waste material, but the present invention can also be applied to a solid PS waste material.
[0003]
[Background]
In recent years, styrene-based resins are widely used as cabinet materials and building materials for various types of electrical equipment. Furthermore, these foams (especially expanded polystyrene) are used as various packaging materials, especially frozen food containers, food display trays, etc. And occur in large quantities in the food market and supermarkets.
[0004]
As a method of reusing (recycling) these materials, waste plastics are thermally decomposed in a pyrolysis furnace such as a retort kettle (dry distillation kettle), and the gaseous pyrolysis products generated thereby are fractionated. A method of condensing by condensing means such as a column (distillation column) and recovering it as cracked oil, that is, a plastic oil conversion method has been known for a long time (Japanese Patent Laid-Open Nos. 6-228569 and 2001-123182).・ Refer to each of 240883 [Prior art].
[0005]
And, in the external heating method that thermally decomposes by the above retort method, the thermal conductivity of the plastic is low and a temperature difference occurs between the outer peripheral part and the central part of the plastic in the reactor. (See JP-A-6-228569, [Problems to be solved by the invention]).
[0006]
"(1) The reaction that occurs in the outer layer and the central part is different, and a vigorous decomposition reaction that produces carbon occurs in the outer periphery of the reactor (retort kettle). Happens.
[0007]
(2) A carbon film due to coking is easily formed on the inner wall of the reactor, and this carbon film hinders heat transfer to the inside, so the heating efficiency is greatly reduced and the supply of reaction energy (pyrolysis energy) is efficient. A large amount of ineffective energy is consumed, and it is uneconomical.
[0008]
(3) The decomposition product has a relatively wide molecular weight distribution, and since the product is an olefin, it is likely to be polymerized during storage or transportation to cause modification of the components, resulting in low economic efficiency. "
In addition, it is bulky to transport styrene resin waste to the oil treatment plant, especially in the case of foamed styrene resin waste, the transport amount per truck and the input amount per pyrolysis furnace. I could not do much.
[0009]
DISCLOSURE OF THE INVENTION
In view of the above, the present invention is unlikely to cause the above-described problems, that is, it can be thermally decomposed with good thermal efficiency, and the quality of recovered components is good. It is an object of the present invention to provide a method for liquefying styrene-based resin waste that can significantly increase the transport amount per truck and the input amount per pyrolysis furnace.
[0010]
In the process of diligently developing to solve the above problems, the inventors of the present invention reduced the volume of the reduced volume styrene resin waste material with a volume reducing agent, and gradually distilled the fractionated fraction. As a result, the present inventors have come up with an oil treatment method for waste styrene resin having the following constitution.
[0011]
In the method of pyrolyzing styrene-based resin waste by thermal decomposition using an external heating method,
Volume reduction process to reduce volume of styrenic resin waste with volume reducing agent (solvent) to obtain volume reduction gel body, and heating and temperature rising process by gradually heating the volume reduction gel body to thermal decomposition temperature Evaporating process or vaporized decomposition product generated in the step, and fractionating (fractionating) sequentially at each recovery set temperature to recover the volume reducing agent and cracked oily product over time,
It is characterized by including.
[0012]
The above-described problems hardly occur when the molten gel body is thermally decomposed into styrene-based resin waste by an external heating method. The reason is estimated as follows.
[0013]
The process of evaporating a solvent (volume reducing agent) having a boiling point lower than the thermal decomposition temperature (230 ° C. or higher) of the styrene-based resin in the process of raising the temperature of the volume-reducing gel used in the present invention to the thermal decomposition temperature Therefore, the temperature equilibrium is maintained for a certain time by the latent heat of vaporization during solvent evaporation. For this reason, when a molten gel body is heated, only the surface portion of the gel body is prevented from being heated first, and the temperature difference between the inside and outside when the styrene-based resin thermal decomposition temperature is achieved is reduced.
[0014]
In addition, since the volume is reduced and heated, the amount of transport per truck can be increased as compared to the case where styrene resin waste is transported from a supermarket and then oiled at the factory. In addition, the throughput per one pyrolysis furnace can be increased, and the productivity is improved in each stage.
[0015]
In the oil treatment method having the above configuration, it is desirable that the external heating method be performed in an oxygen-free atmosphere. When the volume-reduced gel body is pyrolyzed under an oxygen atmosphere (air atmosphere), it is difficult to obtain a high-quality pyrolysis product (oil product) by oxidative decomposition.
[0016]
Further, the volume reducing agent is substantially composed of a true solvent having a boiling point of 200 ° C. or less and a diluent having a boiling point of 60 ° C. or more lower than the true solvent, and the content of the true solvent is 40 to 80%. Things are desirable. In this case, the temperature difference between the inside and outside of the reduced volume gel body (plastic waste material) at the time of thermal decomposition is less likely to occur. This is because two temperature equilibrium portions are formed in the process until the thermal decomposition temperature is reached.
[0017]
Although not affecting the inventive properties of the present invention, the method of reducing the volume of styrene resin (styrol resin) waste material with a volume reducing agent mainly composed of limonene in the method of recycling as a recycled styrene resin. The techniques passed are described in Japanese Patent Laid-Open Nos. H5-263065 and 7-214028 and Japanese Patent Laid-Open No. 2000-334738. However, after these volume reduction treatments, if necessary, a diluent such as ethyl alcohol is added in a later step to precipitate a styrene resin for recycling, and the method for oily treatment of a styrenic resin of the present invention Is different.
[0018]
In the above configuration, the true solvent in the volume reducing agent is a natural organic solvent such as monoterpene or sesquiterpene, the diluent is an aliphatic saturated alcohol having a boiling point of 100 ° C. or less, and the content of the natural organic solvent is 40 to 80 % Is desirable. The terpenes are organic natural products, have no adverse effects on the environment like synthetic organic solvents, have high solubility in styrene resins and have a moderate difference in boiling point from the thermal decomposition temperature of styrene resins (100 to 200 ° C.), and it becomes easy to ensure a temperature difference (over 60 ° C.) with an aliphatic saturated alcohol, and the mixing ratio is within a predetermined range. It becomes easy to hold down.
[0019]
In the above configuration, it is desirable from the viewpoint of versatility and working environment that the true solvent is substantially made of limonene (citrus oil: citrus oil) and the diluent is substantially made of ethyl alcohol.
[0020]
And volume reduction using the said volume reducing agent is normally performed by mixing so that it may become a composition of 35-60% in the total amount with a polystyrene.
[0021]
In each of the above configurations, the recovery set temperature of each component is as follows.
[0022]
Ethyl alcohol: ≦ 145-160 ° C.
Limonene: ≤220-240 ° C
Heavy oil: Higher temperature than the above and the styrene resin oil conversion method of the present invention is applied to foamed styrene resin waste material, and the effect of the present invention becomes remarkable.
[0023]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described. In the following description, “%” means “mass%” unless otherwise specified.
[0024]
The present invention relates to a method for pyrolyzing a styrene resin waste material by pyrolysis by an external heating method.
[0025]
Here, the styrene resin means a polymer of styrene (polystyrene) and a polymer mainly composed of styrene, so-called polystyrene, impact-resistant polystyrene, acrylonitrile-styrene (AS) resin, acrylonitrile-butadiene-styrene (ABS). ) Resin is included.
[0026]
FIG. 1 is a flow diagram showing an example of a plastic oil making apparatus equipped with an external heating type pyrolysis furnace used in the present embodiment.
[0027]
Basically, the present plastic oil making apparatus includes a pyrolysis furnace 11, a distillation column 13, a low-boiling component recovery, that is, a first condenser 15 for recovering a volume reducing agent (solvent), a high-boiling component recovery, That is, a cracked oil product separator 17 for recovering a pyrolyzate (heavy oil product) is provided.
[0028]
Here, in the pyrolysis furnace 11, two first and second retort kettles 21 and 23 are arranged in parallel inside the furnace body 19, and the steam (vaporized) flow of each of the retort kettles 21 and 23. At the outlet, a steam pipe 25 to the raw material (steam) supply port 13a of the distillation column 13 is arranged. Although not shown, each of the retort kettles 21 and 23 is provided with a nitrogen gas filled pipe so that the reduced gel body can be pyrolyzed under dry distillation and in a substantially oxygen-free atmosphere.
[0029]
A reflux pipe 29 provided with a reflux pump 27 that returns to the top of the distillation column 13 through the first condenser 15 is disposed from the top of the distillation column 13. This is to improve the separation of the vapor from the distillation column 13. And from the bottom part of the 1st condenser 15, it is made possible to collect | recover a low boiling point component (dispersion solvent in a gel body) as a distillate. A waste gas pipe 35 is disposed from the top of the first condenser 15 to be introduced into the water tank 16 as waste gas.
[0030]
In the above, in order to obtain a high-quality product as the recovered solvent and cracked oily product, a distillation column (rectification column) having a reflux mechanism and an oily product separator provided with a condenser were used, but without a distillation column. Two separators equipped with a condenser may be provided, or may be recovered by multistage distillation using one distillation column, and the configuration for separation and recovery may be arbitrary.
[0031]
Furthermore, from the bottom of the distillation column 13, an oily product pipe 33 for taking out a high boiling point component (oiled product) as a bottoms (bottom) and introducing it into the oily product separator 17 is disposed. At this time, the oil product separator 17 includes the second condenser 18, and the cracked oil pipe 33 is heated by the exhaust gas pipe 35 from the thermal cracking furnace 11 on the way. This is for rectifying the oily product (decomposed oil). The cracked oil can be recovered from the bottom of the oil separator 17 via the oil pump 37. From the top of the second condenser 18, as in the case of the first condenser 15, a waste gas introduction pipe 35 that introduces waste gas into the water tank 16 is disposed.
[0032]
The oily treatment method for styrene resin waste material according to the present invention basically comprises the following steps.
[0033]
(1) Volume reduction step: This is a step of obtaining a volume reduction gel body by reducing the volume of the styrene resin waste material with a volume reducing agent (solvent).
[0034]
Here, the volume reducing agent is not particularly limited as long as it is a solvent capable of dissolving a styrene resin waste agent to form a volume reducing gel. Usually, a true solvent (good solvent) having a boiling point of 200 ° C. or less, preferably 200 to 150 ° C., and a diluent (preferably compatible with the true solvent) having a boiling point of 60 ° C. or more lower than that of the true solvent, preferably 80 to 120 ° C. It is desirable to use a mixed solvent with a poor solvent that does not dissolve the styrene resin.
[0035]
This is because a volume-reducing gel body is easily formed by mixing the true solvent and the diluent. Styrenic resin dissolves due to the dissolving action of the true solvent, but at the same time, the dissolving resin forms a fine network structure due to the action of the diluent (poor solvent) in the volume reducing agent, and the volume reducing agent is contained in the network structure. Presumed to be retained and become a volume-reducing gel. This volume-reducing gel body is a cocoon-shaped or water-filled stubby with a volume-reducing agent held inside, and is a very viscous semi-solid that has a stringiness when taken out with fingers. It is a gel. The volume reduction rate varies depending on the expansion ratio, but in the case of normal expanded polystyrene, it is 1/50 or less.
[0036]
In addition, by setting the true solvent and diluent to the above boiling point, as described above, the volume-reducing gel body reaches the thermal decomposition temperature of the styrene resin through the two-stage vaporization step (temperature equilibrium portion). The effect of reducing the temperature difference between the inside and outside of the volume-reducing gel body (styrene-based resin waste material) at the time of thermal decomposition is easily secured.
[0037]
Here, as the true solvent, ethyl esters such as ethyl formate (bp. 53 to 57 ° C.), ethyl acetate (bp. 75 to 80 ° C.), or ketones such as acetone (bp. 55 to 60 ° C.) 55 may be used. If it is soluble in the styrene resin and only one vaporization step is required, it can be used. These have a boiling range of 100 ° C. or less as described above, and cannot secure a diluent having a boiling point of 60 ° C. or more lower than that of the true solvent, resulting in a two-stage vaporization step having a temperature difference (60 ° C.) of a predetermined value or more. Can not go through. Moreover, since these are petroleum-based organic solvents, they are not desirable from an environmental point of view.
[0038]
Therefore, it is desirable to use a natural organic solvent such as monoterpene or sesquiterpene because it is easy to select a high boiling point close to 200 ° C. in the working environment. Of these, monoterpenes are desirable, and limonene (usually d-limonene) (bp. 175.5 to 176 ° C.) can be suitably used, but other terpenes can also be used in combination with other terpenes. Of course.
[0039]
The diluent is preferably an aliphatic saturated alcohol. Specifically, the aliphatic saturated alcohol having a boiling point of 100 ° C. or lower includes methyl alcohol (bp. 64 to 66 ° C.), ethyl alcohol (bp. 77 to 80 ° C.). ), Isopropyl alcohol (bp. 79-82), s-butyl alcohol (bp. 98-102 ° C.), t-butyl alcohol (bp. 78-85 ° C.) and the like can be used alone or in appropriate combination. However, it is preferable to use ethyl alcohol as a main component from the viewpoint of toxicity and odor. The boiling points of the above-mentioned solvents are quoted from “Chemical Handbook Application Edition, revised edition 3”, Maruzen, Table 9.23. Limonen is quoted from 9-642A, Kyoritsu Shuppan Kyoritsu Publishing.
[0040]
The mixing ratio of the two is such that the content of the true solvent is 40 to 80%, preferably 50 to 70%. If the content of the true solvent is too small, the solubility is inferior and the volume reduction rate becomes small. If the content of the diluent is too small, the effect of undergoing the two-stage vaporization process becomes small. This is because the temperature equilibration time of the vaporization process is shortened. As a specific commercially available product, a product manufactured and sold by Eco Factory under the trade name “Eco Katon 50” can be used. The composition of “Ecocaton 50” contains about 60% citrus peel extract.
[0041]
The amount of the volume reducing agent added to the styrene resin waste material is 30 to 60%, preferably 35 to 55%, more preferably around 40% in the total amount with the waste material (styrene resin). Addition is performed to reduce the volume.
[0042]
This volume reduction is performed by adding appropriately crushed waste material to a sealable container container, and then adding a volume reducing agent and stirring, or conversely, putting a predetermined amount of volume reducing agent in the container container, Continue to add until the styrene-based resin waste material cannot be reduced in volume (no longer progresses). At this time, if necessary, the diluent may be heated to a temperature at which evaporation of the diluent hardly occurs (for example, 40 ° C. or less).
[0043]
The volume-reduced gel body thus prepared with super or the like is transported by truck or the like to the oil processing plant while being sealed in a container.
[0044]
(3) Oiling process: The volume-reducing gel is heated to the thermal decomposition temperature, and the evaporated or decomposed vapor generated during the heating temperature is fractionated (fractionated) to reduce the volume and decompose. The process of collecting oily products.
[0045]
In the process of cracking and oil-degrading the volume-reduced gel body, the temperature equilibrium is maintained for a certain time by evaporating the solvent (volume-reducing agent component) before the thermal decomposition temperature is reached. For this reason, since the thermal decomposition temperature is reached through a stage in which there is substantially no internal / external temperature difference until the thermal decomposition temperature is achieved, the internal / external temperature difference of the reduced-volume gel body (raw material) becomes small.
[0046]
The oil conversion treatment is performed using the oil treatment apparatus shown in FIG.
[0047]
[Test example]
A volume-reducing gel body obtained by adding a volume-reducing agent (60% limonene, 40% ethyl alcohol) so as to be 60% in the total amount with the expanded polystyrene is obtained in the apparatus shown in FIG. Since the bottom set temperature of the two retort kettles 21 and 23 is raised in three stages so that each becomes the following, it is introduced into the distillation column 13 and the temperature starts to rise when there is no distillate at each recovery set temperature . The liquid (ethyl alcohol, etc. ) stored so far was sequentially extracted from the bottom of the distillation column 13 and proceeded to the next temperature setting.
[0048]
< Set recovery temperature >
(1) Recovery of ethanol (ethyl alcohol) : 150 ° C. (furnace temperature 300 to 320 ° C.)
(2) Recovery of limonene: 230 ° C. (380 to 400 ° C.)
(3) Recovery of polystyrene oil: 380 ° C. (560-580 ° C.)
The result is shown in the graph of FIG. A substantially clean fraction could be obtained, and about 95% of the raw material could be recovered as reusable ethanol and limonene and as a high-quality cracked oil.
[0049]
[Possibility of industrial use]
In the above description, the styrene resin waste material is taken as an example. However, the technical idea of the present invention can be expected to be applied to plastic waste materials, particularly polyolefin waste materials that can be easily oiled.
[Brief description of the drawings]
FIG. 1 is a flowchart showing an example of an oil treatment apparatus used in the method for oily treatment of styrene resin waste material of the present invention. FIG. 2 shows a temperature curve and each distillate in one test example of the oily treatment method of the present invention. Graph showing the relationship between volume (outflow) [Explanation of symbols]
DESCRIPTION OF SYMBOLS 11 Pyrolysis furnace 13 Distillation tower 15 1st condenser 17 Decomposition | decomposition oil decomposition product separator 21 1st retort pot 23 2nd retort pot

Claims (10)

In the method of pyrolyzing styrene-based resin waste by thermal decomposition using an external heating method,
Volume reduction process to reduce volume of styrenic resin waste with volume reducing agent (solvent) to obtain volume reduction gel body, and heating and temperature rising process by gradually heating the volume reduction gel body to thermal decomposition temperature Evaporating process or vaporized decomposition product generated in the step, and fractionating (fractionating) sequentially at each recovery set temperature to recover the volume reducing agent and cracked oily product over time,
A method for oil-treating styrene-based resin waste material, comprising:   2. The method for liquefying styrene resin waste according to claim 1, wherein the external heating method is performed in an oxygen-free atmosphere.   The volume reducing agent is substantially composed of a true solvent having a boiling point of 200 ° C. or less and a diluent having a boiling point of 60 ° C. or more lower than the true solvent, and the content of the true solvent is 40 to 80%. A method for oily treatment of styrene-based resin waste material according to claim 1 or 2, wherein a material is used.   The styrene resin waste material according to claim 3, wherein the true solvent in the volume reducing agent is a natural organic solvent such as monoterpene or sesquiterpene, and the diluent is an aliphatic saturated alcohol having a boiling point of 100 ° C or lower. Oiling method.   5. The method for oily treatment of styrene resin waste material according to claim 4, wherein the true solvent is substantially composed of limonene (citrus oil: citrus oil), and the diluent is substantially composed of ethyl alcohol.   The styrene-based resin waste material according to claim 4 or 5, wherein the volume reduction is performed by mixing so that the volume reducing agent has a composition of 35 to 60% in a total amount with the styrene-based resin waste material. Oiling method. The recovery set temperature of each component is
Ethyl alcohol: ≦ 145-160 ° C.
Limonene: ≤220-240 ° C
Oiled product: The method for oiling a styrene resin waste material according to claim 5 or 6, wherein the temperature is higher than the above.   8. The method of oily treatment of styrene resin waste material according to claim 1, wherein the styrene resin waste material is foamed styrene resin waste material. In the method of thermally decomposing plastic waste by external heating method,
Volume reduction process to reduce volume of plastic waste with volume reducing agent (solvent) to obtain volume-reduced gel body, and temperature-reducing temperature of the volume-reduced gel body is gradually raised to thermal decomposition temperature An evaporating step for fractionating (fractionating) the evaporate or cracked vaporized product with time at each recovery set temperature to recover the volume reducing agent and the cracked oily product,
A method for oily treatment of plastic waste material, comprising:   10. The method for oil-treating plastic waste material according to claim 9, wherein the plastic is an olefin resin.

Images