KR101134809B1 - Method for producing pulverized waste plastic - Google Patents

Abstract

It is possible to obtain a pulverized product by pulverizing waste plastic at low cost, and to provide a method for producing waste plastic pulverized product, which also improves the productivity of the pulverized product. The waste plastic is kneaded at a shear rate of 100 (1 / sec) or more at the same time as melting at a temperature above the softening melting temperature and no flammable decomposition gas is produced, and then cooled and solidified to be a solid, and the solid is pulverized. A method for producing waste plastic pulverized product is used. It is preferable that the softening melting temperature is 160 degrees C and the temperature at which flammable decomposition gas is not produced is 270 degrees C or less. Alternatively, the waste plastic is kneaded at 160 ° C. to 270 ° C. and kneaded at a shear rate of 100 (1 / sec) or more, and then cooled and solidified to a solid, and the solid is pulverized. Use It is preferable to perform melt-kneading using an extruder, and especially to use a twin screw extruder.

Description

Manufacturing method of waste plastic pulverization {METHOD FOR PRODUCING PULVERIZED WASTE PLASTIC}

The present invention relates to a method for producing waste plastic pulverized product for regenerating waste plastic to produce ore reducing materials, solid fuels and the like.

In recent years, as one solution for the effective use of waste plastics, a method of producing ore reducing materials, solid fuels and the like from waste plastics has been studied. This is because micronization of plastics greatly improves combustibility and can be a useful fuel resource.

Conventional techniques for converting plastics into solid fuel have been, for example, grinding the plastics directly into a pulverizer (see Non-Patent Document 1, for example). However, in this method, the hard plastic can be pulverized only to a particle size of 1 to 2 mm, and this pulverization requires enormous time and cost, and also fibrous or film-like ( (Iii) Since the plastic of i) is difficult to grind, it has to be grind | pulverized after melt solidification separately, and there existed a problem of a complicated process.

In addition, it is known that when finely pulverized waste plastic can be used as a fuel that can be used as a combustion furnace such as a power generation boiler (see Patent Document 1, for example). There is no description and there is no technical disclosure regarding the improvement of the crushability of the waste plastic itself.

Plastics having a particle diameter of 2000 µm or less are excellent as solid fuels and are known to be produced by a dry grinding method or a wet grinding method (see Patent Document 2, for example). In particular, as a method for obtaining fine powder, a jet mill or a vibrating ball mill may be said to be suitable, but this technique is also known for improving the pulverization property of waste plastic itself. Not.

On the other hand, for example, when waste plastic discharged from a home or the like is used as a reducing material or fuel such as a blast furnace reducing material, the waste plastic includes chlorine-containing plastic such as polyvinyl chloride (hereinafter referred to as PVC). If mixed as it is, there is a problem that hydrogen chloride or the like is generated and the furnace is corroded. For this reason, the technique (for example, refer patent document 3) which separates and removes chlorine-containing plastics, such as PVC, performs granulation process, and obtains a granular plastic molded object is known.

Further, as a technique for dechlorination of waste plastics containing chlorine and then micronizing waste plastics, the waste plastics are heated, dechlorinated, cooled and solidified, and then pulverized and put into a furnace (eg For example, techniques, such as patent document 4 and patent document 5, are known.

[Patent Document 1] Japanese Patent Application Laid-Open No. 7-119922 [Patent Document 2] Japanese Patent Application Laid-Open No. 4-332792 [Patent Document 3] Japanese Patent Application Laid-Open No. 2002--67029 [Patent Document 4] Japanese Patent Application Laid-Open No. 11-192469 [Patent Document 5] Japanese Patent Application Laid-Open No. 2006-241442

[Non-Patent Document 1] "Plastic" Vo1.47, No. 7, p60, 1996

In general, since plastics have excellent impact resistance, it is very difficult to grind them as they are, and especially when grinding to a particle diameter of 0.5 mm or less, methods such as lengthening the grinding time or repeatedly inputting the grinder several times are wasteful. do. In this case, depending on the type of the pulverizer, it is confirmed that the plastic is heated by shearing heat during pulverization and melted, or the pulverized product becomes fibrous. In order to prevent this phenomenon, cooling of the grinder or the pulverized product is considered, but the equipment cost and the running cost increase.

As a method of finely pulverizing plastic, so-called freeze grinding is also a viable means. That is, a method of pulverizing the plastic after cooling the plastic to a temperature range where general plastic causes brittle fracture, for example, minus tens of degrees. However, since this method needs to cool the plastic in advance, the equipment cost and the running cost increase.

According to the so-called waste dechlorination method of waste plastics including the methods described in Patent Documents 4 and 5, the PVC after dechlorination is carbon-nitrated and embrittled, thereby improving the crushability as a whole. It is possible. However, it is necessary to perform the treatment of the exhaust gas containing chlorine generated by the dechlorination treatment, resulting in high cost. It is also possible to recover chlorine from the exhaust gas and effectively use it as hydrochloric acid, but this also causes an increase in the installation cost. In order to manufacture waste plastic finely ground at low cost, it is important to reduce equipment cost and improve productivity.

Accordingly, an object of the present invention is to provide a method for producing waste plastic pulverized product, which can solve the problems of the prior art and obtain a pulverized product by pulverizing waste plastic at low cost, and also improves the productivity of the pulverized product. have.

Features of the present invention for solving these problems are as follows.

(1) Container packaging The waste plastic is melted at 160 ° C to 270 ° C and kneaded at a shear rate of 100 (1 / sec) or higher, and then cooled and solidified to a solid, and the solid is pulverized to a particle diameter of 2 mm or less. Method for producing a waste plastic pulverization characterized in that.

(2) A method for producing the waste plastic pulverized product according to (1), wherein melting and kneading are performed using an extruder.

(3) The manufacturing method of the waste plastics pulverized product as described in (2) characterized by the extruder being a twin screw extruder.

(4) Container packaging (1) to (3), characterized in that solid granules other than the waste plastic are mixed and kneaded together with the waste plastic before melting and kneading and / or melting and kneading the waste plastic. The manufacturing method of the waste plastic grinding material as described in any one of them.

(5) The method for producing waste plastic pulverized product according to any one of (1) to (3), wherein the particle size of the solidified product pulverized by passing through a sieve is adjusted.

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According to the present invention, a solid fuel or an ore reducing material having excellent combustibility can be produced using waste plastic as a raw material at low cost without providing a facility for treating exhaust gas from waste plastic. The productivity of waste plastic pulverization is also improved.

In addition, by using the waste plastics treatment method of the present invention, it is possible to economically perform mass processing of waste plastics.

1 is a graph showing the relationship between the melting temperature of plastic waste and the decomposition rate of plastics.
2 is a graph showing the relationship between the shear rate and viscosity of plastics.

In the present invention, waste plastics or container packaging materials contained in municipal waste, industrial waste, general waste, etc., and waste plastics generated during dismantling of electrical products, automobiles, etc., are cooled and melted after heating, melting and kneading to form solids. The present invention relates to a technology for producing a solid fuel, an ore reducing material, and the like by pulverizing the powder. As mentioned above, waste plastics are a mixture of plural kinds of plastics, and it is effective to melt-knead various kinds of plastics as a method for improving the pulverization of waste plastics and making them easily finely divided. Since most waste plastics contain chlorine by incorporation of PVC or the like, conventionally, chlorine-containing gas is generated by melting and kneading the waste plastics at a high temperature at which chlorine gas is generated, and the chlorine component is removed from the waste plastic pulverized product. The dechlorination process to remove was performed.

However, in order to sufficiently dechlorine, for example, when treated at a temperature of 300 ° C. or more, PET (polyethylene terephthalate) or paper and wood (cellulose, hemicellulose ( hemicellulose), lignin) and the like are pyrolyzed and hydrolyzed to produce flammable decomposition gas (combustible organic matter). Since most of these flammable decomposition gases are solid at room temperature and generally have a sublimation property, the structure of the collecting device becomes complicated, and they need to be treated separately. In addition, a collection contains many% of chlorine, and it is hard to be a fuel.

Then, in this invention, in order to prevent generation | occurrence | production of the flammable decomposition gas which arises when the waste plastics are heated and melted and kneaded, the method of performing melting and kneading at comparatively low temperature was examined. When melting at a relatively low temperature, it was a problem that chlorine removal from waste plastic could not be sufficiently performed. However, when waste plastic having a low chlorine content is used, waste plastic solids or pulverized products having low chlorine concentration can be produced without dechlorination treatment. can do. Therefore, in this invention, it is preferable to use waste plastics with low chlorine content (for example, chlorine concentration of 2 mass% or less). As a result of the investigation, it was found that the content of chlorine to some extent is acceptable, and dechlorination is not necessarily necessary in all cases. For example, when the waste plastic pulverized product is used for the ore reducing material of the blast furnace, the dechlorination treatment can be omitted depending on the amount of chlorine contained in the waste plastic because the slag component present in the furnace reacts with chlorine and is immobilized. . In addition, even if the chlorine concentration of the raw material waste plastic is high and the chlorine content of the pulverized product is high, this does not mean that it cannot be used as an ore reducing material or a solid fuel, and the amount per unit time is appropriately adjusted according to the chlorine concentration. The occurrence of problems such as corrosion can be avoided. Therefore, even if the waste plastic pulverized product manufactured without performing dechlorination treatment does not produce a practical problem if it is pulverized enough.

On the other hand, by melting at a relatively low temperature, the PVC after dechlorination becomes carbonitized, and the effect of embrittlement cannot be obtained. Therefore, the pulverization property of the produced waste plastic solids is lowered and productivity is lowered. On the other hand, it was found that by sufficiently improving the degree of kneading in the melt-kneading process of the waste plastic, it is possible to suppress the deterioration of the pulverization to a problem-free level. At the same time, by melting at a low temperature and preventing the generation of flammable cracked gas, the components which would be removed as flammable cracked gas can be accepted as waste plastic ground, so that the yield is also improved and the productivity of the ground as a whole is also improved.

As described above, the heat treatment of the waste plastic is performed at a temperature not higher than the softening melting temperature and at which the flammable decomposition gas is not generated, thereby increasing the solid yield after the treatment. At this time, the residual chlorine concentration in the solidified body after treatment increases to some extent, but when used as a reducing material for the blast furnace, for example, it reacts with the calcium present in the blast furnace, so that even if the chlorine increases to some extent, it causes a particularly large problem in equipment. I never do that. In addition, when the dechlorination reaction occurs, it is considered that the calorific value of the solidified body increases only as much as chlorine. However, since the organic matter decomposes and detaches as a side reaction, the calorific value of the solidified body after treatment becomes rather small. Therefore, the heat generation of the waste plastic is performed at a temperature at which the flammable decomposition gas is not generated above the softening melting temperature, so that the calorific value of the solidified body does not decrease.

The heating temperature at the time of heating melting, cooling, and solidifying waste plastics is, for example, according to Patent Document 4, the temperature is raised to a temperature for removing the low boiling point compound originally contained and / or produced by pyrolysis. It is a charge agent, specifically, it is 150-450 degreeC, More preferably, it is 200-400 degreeC, More preferably, it is the temperature range of 250-380 degreeC. In such a temperature range, a flammable decomposition gas is produced | generated with hydrogen chloride by heating to high temperature.

In general, in order to perform dechlorination of chlorine-containing plastics, heating to 300 ° C or higher is preferable. In this case, a facility for treating and recovering the generated chlorine gas is required.

Therefore, in a facility in which waste plastics are heated, melted, cooled, and solidified on the premise of dechlorination of waste plastics, waste plastic cracking gas generated in the hot melting process of waste plastics, hydrochloric acid recovery apparatus, and the like. Chlorine treatment equipment is needed. Since these facilities are expensive, the present inventors examine the temperature at which flammable cracked gas is generated when melting and kneading, cooling and solidifying to solidify in order to reduce the processing cost of waste plastic. The relationship shown in FIG. 1 was found about the temperature to heat-melt and the decomposition rate of a plastics. On the other hand, the decomposition rate is defined as (daily recovery amount / throughput amount) × 100 (mass%) using a comparison between the amount of waste plastic used in the treatment (a throughput amount, a dry base) and a recovery amount after the treatment.

According to FIG. 1, generation of waste plastic cracking gas is extremely low up to 270 ° C. Therefore, by heating, melting and kneading the waste plastic below the generated temperature of the cracked gas, and cooling and solidifying, the waste gas treating equipment such as a combustion furnace is unnecessary, and the waste plastic is processed at low cost to produce waste plastic solids. can do.

If the chlorine remaining in the waste plastic is low in concentration, it does not often cause problems when used in ore reducing materials, solid fuels, and the like. It is preferable to use a waste chlorine having low chlorine concentration in the present invention. For example, treating waste plastics having a chlorine concentration of 2% by mass or less by the method of the present invention can be sufficiently used for blast furnace injection as an ore reducing material.

The temperature at which the flammable cracked gas is not produced varies slightly depending on the type of waste plastic. However, in general, the temperature is preferably 270 ° C or lower than the result of FIG. Moreover, when it is 200 degrees C or less, generation | occurrence | production of a flammable gas can be prevented more reliably. The temperature in this case is taken as the highest temperature in resin. The maximum temperature in resin can be measured by the general method, such as inserting a thermocouple in resin. On the other hand, the temperature at which flammable decomposition gas is not generated is a temperature at which flammable organic matter is not substantially generated from waste plastic by heating, and is likely to be caused by impurities in waste plastic (for example, liquefied gas in disposable lighters). The gas is outside of the combustible cracked gas in this case.

The lower limit of the melting temperature is a temperature at which the waste plastic softens and melts in order to knead the waste plastic well as will be described later. The softening melting temperature varies depending on the type of waste plastic. However, since the main components of ordinary waste plastic are polyethylene (PE) and polypropylene (PP), it is preferable to set the lower limit of the softening melting temperature to 160 ° C. It is also possible to set it as 120 degreeC if only PE is used as a waste plastics.

However, it is not practical to perform the melting and kneading treatment at less than 160 ° C because the waste plastic of the object to be treated is a mixture of various plastics. In other words, only plastics melted below 160 ° C are mainly PE, and if the processing is excessively required, the power required for kneading becomes extremely large, and the closing occurs in the processing apparatus, making it difficult to continue the processing. There is.

"Melting and kneading waste plastic" refers to kneading waste plastic at the same time as melting the waste plastic, or kneading waste plastic in a molten state after melting. Here, kneading is performed at a shear rate of at least 100 (1 / sec) or more. By sufficiently kneading, heterogeneous plastics are mixed and highly dispersed, and the heterogeneous interface of the plastics increases, and the origin of breakage is expressed. Plastics differ in their characteristics, and when these solid plastics are melt-kneaded and then cooled and solidified, the polymers solidify while being sufficiently mixed with each other, but the adhesive interface is not chemically but only in physical contact. On the other hand, the molding shrinkage of dissimilar plastics is different in each plastic, and during cooling, the dissimilar plastics shrink according to their molding shrinkage rate, and the inside must be vacuumed to separate the adhesive interface (vaid void). )), If no void formation is reached, a stress "trying to separate but cannot be separated" remains at the bonding interface (residual stress). Highly dispersed heterogeneous plastics due to sufficient kneading have a large adhesive interface, and the solid body inevitably has a strong residual stress. When the solidified body is impacted, stress concentration is caused on these dissimilar plastic bonding interfaces, and a starting point of breakage is generated relatively easily. Moreover, since there is no element which prevents the propagation of a crack, as a result, the whole becomes a fragile structure and the grinding property improves. In addition to the molding shrinkage rate, differences in dissolution parameters and the like also affect the improvement of crushability.

Solid granules other than waste plastics are also incompatible with plastics in most cases, and therefore, before or after melting or kneading waste plastics, or both before melting and kneading and during melting and kneading. By mixing solid granules other than the waste plastics with the waste plastics and kneading them with the waste plastics, after cooling and solidifying, the solid granules are the starting point of destruction, and the crushability of the solids can be further improved.

As a method of mixing before melting and kneading, for example, a tumbler or the like may be used to mix the waste plastic and the solid particulate material in advance. As a method of mixing at the time of melting and kneading, the waste plastic and the solid granular material may be separately supplied to the melting and kneading apparatus, and may be mixed in the apparatus, or either may be supplied first and then the other may be supplied. If the melting point of the solid particulate is higher than the melting start temperature of the waste plastic, it is preferable to first feed the waste plastic and to achieve a certain molten state before adding the solid particulate.

Examples of solid granular materials include fossil fuels such as coal, coke and asphalt, synthetic polymers such as virgin plastics, natural polymers such as starch and cellulose, metals such as iron and aluminum, and their ores such as iron ore and bauxite, Inorganic substances such as mica and talc. In addition, it is preferable to use so-called biomass solids such as lignin plants contained in crop-derived wastes such as rice hulls, tea grounds and coffee shells, wood, charcoal or bamboo, etc. as solid granular materials. In particular, the use of waste derived from crops and waste wood such as thinning and construction waste is useful in terms of global environmental protection. As mentioned above, since the solid granules other than the waste plastics are not compatible with plastics in most cases, they are kneaded with the molten waste plastics, and after cooling and solidified, are the starting point of breakdown, and the crushability can be improved. Particularly, the biomass solid is preferable because it contains ash and tends to be a starting point of destruction. In addition, the chaff tends to be elongated and further pulverized when the molten waste plastic is kneaded, so that it can be effectively used as a starting point of destruction. In addition, it is preferable that the compounding quantity of a solid particulate matter in this case shall be less than 100 mass parts of solid particulate matter with respect to 100 mass parts of waste plastics. This is because the waste plastic is powdered after kneading treatment at 100 parts by mass or more of the solid granular material, which makes it difficult to handle it. Moreover, it is preferable to set it as 5 mass parts or more of solid particulate matter with respect to 100 mass parts of waste plastics. It is because the effect of a solid granular material addition can be exhibited better. These solid particulates can be used as long as they can be introduced into the treatment apparatus.

It is preferable to perform heating and melting of the waste plastic while kneading using an extruder. By using an extruder, while kneading waste plastic, kneading | mixing of shear rate 100 (1 / sec) or more can be performed efficiently. An extruder can further improve kneading | mixing by using a twin screw extruder.

By pulverizing the solidified body of the produced waste plastic, the waste plastic pulverized product can be manufactured, and an ore reducing material and a solid fuel can be manufactured. The solidified body which cooled and solidified after heat-melting improves grindability, and can manufacture the fine powder with a particle diameter of 2 mm or less easily using a normal grinder. The pulverized solid body is preferably passed through a sieve to adjust the particle size. By appropriately changing the body of the sieve, the particle size after grinding can be set. For example, by using a manufacturing method of the present invention, a fine powder, which is a waste plastic pulverized product having a particle size of 0.5 mm or less, can be obtained by passing a sieve having a body size of 0.5 mm.

EMBODIMENT OF THE INVENTION Below, one Embodiment of this invention is described. Plastics, Ⅱ. Melting and Kneading Process, Ⅲ. Cooling solidification process, IV. In order of the grinding | pulverization process, it demonstrates in more detail.

[I. Plastics] The waste plastics of the present invention, that is, the raw material plastics of the present invention include waste plastics and container packaging materials contained in municipal waste, industrial wastes, general wastes, and the like. Waste plastics and the like.

Specifically, polyolefins such as polyethylene and polypropylene, polyvinyl chloride, polyvinylidene chloride, chlorinated polyethylene, polystyrene, polyethylene terephthalate, polycarbonate and nylon, other thermoplastic resins and thermosetting resins are applicable. Any of two or more kinds of plastics are used in a mixed state. Although the waste plastic which is a waste generally contains a certain amount of chlorine-containing plastic, it is possible to use the present invention even if the waste plastic does not contain a chlorine-containing plastic.

The shape dimension of the plastic to be heat-treated is roughly ground, and a size of about 10 cm square is sufficient, and in general waste plastic, there is no need to grind again, and it can be processed in a recovered state, and the film Phase, sheet-like, and fibrous plastics can also be treated in the same form. Of course, fine grinding may be used, but the processing cost will increase accordingly.

[II. Melt-kneading process] The following process is illustrated as a melt-kneading process. That is, the waste plastic is melted in a reactor or in an extruder at 160 ° C. or higher at a temperature at which flammable cracked gas is not generated. The temperature at which flammable cracked gas is not produced varies depending on the composition of the waste plastic, but in general, the upper limit is set to 270 ° C. In the temperature range where a flammable decomposition gas is not produced, it is preferable to melt at higher temperature, Preferably it melts and knead | mixes within the temperature range of 200 degreeC or more, More preferably, 230 degreeC or more.

Kneading is performed at least at 100 (1 / sec) shear rate. The result of having measured the change of melt viscosity with respect to the shear rate in 150 degreeC of various low density polyethylene (MI: Me1t Index = 7,50,200) measured by the capillary rheometer is shown in FIG. Molten plastic is a non-Newtonian fluid, and as shown in FIG. 2, the melt viscosity of low density polyethylene (LDPE) is almost constant in a region having a small shear rate. However, even in the LDPE having any MI, in the region where the shear rate is 100 (1 / sec) or more, the viscosity decreases with the increase in the shear rate. That is, from the viewpoint of kneading property, kneading in a region of shear rate of 100 (1 / sec) or more is extremely effective for lowering kneading power and improving kneading efficiency.

By melting and kneading, the pulverization property of the plastic processed object can be improved. As a result, heterogeneous plastics in the waste plastic are mixed with each other, but since they hardly dissolve with each other and have no interaction with each other, after solidification, they are easily scattered with a slight impact, and since the starting point of destruction is expressed, As a result, impact resistance is lost. The melt kneading treatment may be a batch type or a continuous type. Moreover, you may be intermediate types, such as batch switching. As a continuous processing apparatus, an extruder is preferable and a biaxial extruder is more preferable from a kneading viewpoint.

The treatment time is suitable for 0.5 minutes to 30 hours. If the treatment time is less than 0.5 minutes, it becomes difficult to control the temperature in the reactor and it is difficult to sufficiently knead the melted waste plastics. In addition, when the treatment time exceeds 30 hours, the treatment efficiency is lowered and it is not economical.

In a melt-kneading process, a heat medium can also coexist.

[III. Cooling solidification step] Cooling solidification is performed by quantitatively supplying molten plastic to the belt cooler in the molten plastic conveying apparatus of the waste plastic after the melting treatment. The heat removal amount is calculated from the enthalpy amount between the temperature after the heat treatment and the temperature until solidification sufficiently, and the processing speed. For example, when the container packaging waste plastic is included, the heat removal amount is controlled to be about 110 ° C. Is enough.

Moreover, when using a continuous hot melt processing apparatus, it is possible to perform cooling such as air cooling or submerging in water, with or without cutting at the outlet of the apparatus.

[IV. Grinding process] It is preferable to grind | cure the solidified body which passed through the cooling solidification process so that it may become a predetermined particle diameter. Grinding of the plastic processed material which is the cooling solidified body obtained by the above-mentioned method of this invention can be performed very easily compared with the grinding | pulverization of the unprocessed plastic. That is, the plastic processed material obtained by the method of the present invention can be pulverized by any type of pulverizer, and for example, jaw crusher, roll crusher, ball mill, centrifugal mill and the like can be used as the pulverizer. have.

The particle size after pulverization may be determined according to the purpose of use of the plastics to be processed, and if the particle size is adjusted so as to have a predetermined particle size, for example, an ore-reducing material such as iron ore, that is, a vertical furnace for manufacturing cast iron such as blast furnaces, etc. It can be used as a raw material such as a reducing material, a reducing material of a converter, a fuel for combustion such as a boiler or a kiln, a fuel of a cupola and a coke oven. Moreover, it can be used as a solid fuel besides the use mentioned above.

Example 1

Hereinafter, the present invention will be described in more detail based on Examples.

[Inventive Example 1] General waste container packaging Waste plastics were pulverized to about 1 cm and melted and kneaded at 180 ° C. in a twin screw extruder. The shearing speed during kneading was 243 (1 / sec) (screw diameter 31mm, screw and barrel clearance 0.2mm, screw rotation speed 30rpm, shear rate π × 31 × 30/60 / 0.2 = 243). The generation of water (water vapor) was confirmed from the vent of the extruder, but the flammable cracked gas was not found. This was cooled by air as it was, and the mass (solid body) about 30 mm was obtained.

The yield of solidified body was computed from the usage-amount of raw materials and the collection | recovery amount of solidified body at this time. In addition, the chlorine concentration (solid residual chlorine concentration) in this solid body and the calorific value of the solid body were measured. The results are shown in Table 1.

This solid material was coarsely pulverized with Horei Co., Ltd. (cutter mill), and the screen of 9 mm was passed.

The crude pulverized product was pulverized with an ACM armbellizer (hammer mill) manufactured by Hosokawa Mikuron Co., Ltd., followed by a classification test on a test body, and the particle size distribution was measured. The results are shown in Table 2.

The average particle diameter was calculated from the particle size distribution. First, in the following formula (2) obtained by modifying the following formula (1) (Formula of Rosin-Rammler-Bennet), the mass fraction of each of the four fractions obtained by the classification test and the diameter of the body are substituted. The proportional constants n and b of the following formula (2) were obtained by the square method.

R (Dp) = 100? Exp {-(Dp / De) n}... (One)

log {log [100 / R (Dp)]} = n? logDp + log (b)... (2)

In the above formulas (1) and (2), R (Dp) is the sieving integration mass% of the body Dp, De is the particle size characteristic number [R (Dp) is the number corresponding to the mass%], and n is the equivalent number ( The index which evaluates the uniformity of particle size distribution of a granular material), and b are integers, and represent the index which evaluates the fineness of a granular material.

From the obtained n and b, D50 (50% sieve diameter) was calculated and the average particle diameter was calculated. The average particle diameter is shown together in Table 1. The average particle diameter of the waste plastic pulverized product of Example 1 of the present invention subjected to the melt treatment at 180 ° C. was less than 500 µm and sufficiently fine.

[Inventive Example 2] The fine powder was ground to about 1 cm. 70 mass parts of general waste container packaging waste plastics and 30 mass parts of rice husks were mixed, and it carried out similarly to Example 1 of this invention except having supplied to the twin screw extruder, and the solidified body and its pulverized material were manufactured. Table 1 and Table 2 show the results of the measurement of the solid yield, the residual chlorine concentration in the solid, the calorific value of the solid, the average particle diameter, and the particle size distribution after pulverization.

Compared with Example 1 of the present invention, the yield of solids increased, the residual chlorine concentration in the solids decreased, and the amount of heat generated in the solids decreased to some extent. This indicates that most of the rice hulls containing about 20 mass% of ash remained in the solid after treatment. Moreover, the average particle diameter after grinding | pulverization became small, and the grinding | pulverization improvement effect by chaff addition was confirmed.

[Example 3 of the Invention] Example 1 of the present invention was used except that 70 parts by mass of general waste container packaging waste plastic pulverized to about 1 cm and 30 parts by mass of coal (acid name: 산) were mixed and fed to a twin screw extruder. The same operation was performed to produce a solid and a pulverized product thereof. The measurement results of the solid body yield, the residual chlorine concentration in the solid body, the solid body calorific value, the calculation result of the average particle diameter, and the measurement result of the particle size distribution after pulverization are shown in Table 1 and Table 2 together.

Compared to Example 1 of the present invention, the yield of solids was increased, the residual chlorine concentration in the solids was reduced, and the amount of solids calorific value decreased. This indicates that most of the coal containing about 10 mass% of ash remained in the solidified body even after treatment. Moreover, the average particle diameter after grinding | pulverization became small, and the grinding | pulverization improvement effect by the addition of coal was confirmed. Also in comparison with Example 2 of the present invention, the average particle size after grinding is smaller, but this is because the added coal itself has better grinding property than rice hulls.

COMPARATIVE EXAMPLE 1 Except having made the kneading | mixing temperature by the twin screw extruder into 335 degreeC, operation similar to Example 1 of this invention was performed, and the solidified body and its grind | pulverized material were manufactured. From the vent of the twin screw extruder, the exhaust gas which consists of hydrogen chloride gas and organic substance other than water was confirmed. Terephthalic acid was detected in the components of the exhaust gas. The measurement results of the solid body yield, the residual chlorine concentration in the solid body, the solid body calorific value, the calculation result of the average particle diameter, and the measurement result of the particle size distribution after pulverization are shown in Table 1 and Table 2 together.

In Comparative Example 1, the residual chlorine concentration in the solid was sufficiently lowered. Moreover, although the average particle diameter was small and micronized, the main reason was the high ratio of the ultrafine powder of 75 micrometers or less. Moreover, this ultrafine powder of 75 micrometers or less has a safety problem, such as having dust generation, and the countermeasure facility cost, such as nitrogen encapsulation, is needed.

[Comparative Example 2] A classification test was conducted in the same manner as in Example 1 of the present invention, except that the shear rate at the time of kneading by the twin-screw extruder was 81 (1 / sec) (screw rotation speed 10 rpm). The measurement results of the solid body yield, the residual chlorine concentration in the solid body, the solid body calorific value, the calculation result of the average particle diameter, and the measurement result of the particle size distribution after pulverization are shown in Table 1 and Table 2 together.

In comparison with Example 1 of the present invention, in Comparative Example 2 in which the shear rate at the time of kneading is outside the range of the present invention, it is evident that the average particle diameter is not greatly differentiated.

[Comparative Example 3] A classification test was conducted in the same manner as in Example 2 of the present invention except that the kneading temperature of the twin screw extruder was set to 335 ° C. From the vent of the twin screw extruder, the exhaust gas which consists of hydrogen chloride gas and organic substance other than water was confirmed. In the components of the exhaust gas, terephthalic acid was detected. The results of the measurement of the solid body yield, the residual chlorine concentration in the solid body, the solid body calorific value, the calculation result of the average particle diameter, and the measurement result of the particle size distribution after pulverization are shown together in Table 1 and Table 2. .

In the comparative example 3, although the average particle diameter was small and micronized, this main reason was a high ratio of the ultrafine powder of 75 micrometers or less. Moreover, this ultrafine powder of 75 micrometers or less has a safety problem, such as having dust generation, and the countermeasure facility cost, such as nitrogen encapsulation, is needed.

[Comparative Example 4] The same treatment as that of Example 1 of the present invention was attempted except that the treatment temperature at the time of kneading by the twin screw compressor was set to 140 ° C. However, about 5 minutes after the start of the treatment, the screw motor stopped due to overload and the treatment could not be continued. After cooling the twin screw extruder, the screw was pulled out, and the waste plastic solid of unmelting was clogged inside.

From the above results, it can be seen that in Examples 1 to 3 of the present invention, in spite of melting and kneading at low temperature, both of the pulverized products were finely ground to an average grain boundary of 500 µm or less. By addition of rice hull and coal, grinding property improves further. Comparing Inventive Example 1 and Comparative Example 1, in Inventive Example 1, the residual chlorine concentration in the solidified body was not lowered, but the solidified body yield was increased and the solidified body calorific value was also increased. It is apparent that the productivity of the pulverized product is thereby improved. This is because, in Comparative Example 1, the terephthalic acid, which is a combustion component, is also released in the course of dechlorination, but in the example of the present invention, the combustion component remains.

On the other hand, when comparing the comparative example 3 with the comparative example 1, even if it is the addition of rice husk, it is also considered that the average particle diameter is large, and, at first glance, crushability falls. In Comparative Example 3, however, the average particle diameter slightly increased, but according to Table 2, Comparative Example 3 had a higher ratio of particle diameters of 150 to 500 µm and 75 to 150 µm than Comparative Example 1, and the width of the particle size distribution was narrowing. The grinding property is improved. Therefore, the effect of "adding a rice husk" to express more favorable grinding property by forming the origin of destruction was confirmed.

Claims (13)

Container packaging The waste plastic is melted at 160 ° C to 270 ° C, and kneaded at a shear rate of 100 (1 / sec) or more, and then cooled and solidified to obtain a solid. The solid is a particle diameter of 2 mm. Method for producing a waste plastic pulverized product, characterized in that pulverized below. The method of claim 1,
Melting and kneading are performed using an extruder. The method of claim 2,
The extruder is a twin screw extruder. 4. The method according to any one of claims 1 to 3,
Container Packaging Before the melting and kneading of the waste plastics and / or during the melting and kneading, solid granules other than the waste plastics are mixed and kneaded together with the waste plastics. Way. 4. The method according to any one of claims 1 to 3,
A method for producing a waste plastic pulverized product, characterized by adjusting the particle size of the solidified product pulverized by passing through a sieve. delete delete delete delete delete delete delete delete

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