JP2006022337A - Processing method for plastics and solid fuel and ore reducing agent using processed plastics - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a processing method for plastic that can produce easily grindable plastic processed products, and obtain solid fuel and ore-reducing agent by utilizing the plastic processed products. <P>SOLUTION: Plastics are heat-treated at a temperature higher than 150°C, and the formed low boiling components are removed from the product. Then, the remainder is cooled down and solidified, If necessary, further ground. As a plastic, two or more different kinds of plastics except chlorine-including resins are preferably combined. The resultant plastic processed product is brittle and can readily be crushed into fine particles. As fine particle powder substantially chlorine-free is obtained, it can be used as a pollution-free fuel having excellent combustibility or as a reducing agent. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a plastic processing method capable of obtaining a plastic processed product that can be easily pulverized, a solid fuel obtained by the processing method, a reducing agent for ore, and further a chlorine-containing plastic such as polyvinyl chloride. The present invention relates to a plastic processing method capable of converting a contained plastic into a plastic processed material substantially free of chlorine, and a solid fuel and ore reducing agent obtained by the processing method.

As a solution for effective utilization of waste plastics in recent years, a method of producing solid fuel from waste plastics can be considered.
This is because, when plastics are pulverized, the flammability is dramatically improved and can become a useful fuel resource.
A conventional technique for converting plastic to solid fuel is to directly pulverize plastic with a pulverizer as described in Non-Patent Document 1, for example.

However, in this method, a hard plastic must be crushed to a particle size of 1 to 2 mm, and this pulverization requires a lot of time and cost. In addition, it is difficult to pulverize fiber or film plastics. Therefore, it has to be separately pulverized after being melted and solidified, resulting in problems such as complicated processes.
Furthermore, plastics containing chlorine, such as polyvinyl chloride, generate dioxins, which are harmful when incinerated, and when heated, hydrogen chloride gas is generated and corrodes containers and piping. Separately, it is necessary to dehydrochlorinate by heat treatment or the like.
Plastics Vol.47, No.7, p60

  The present invention solves the above-mentioned problems of the prior art, and can be processed even if films are mixed. Moreover, dehydrochlorination can be performed at the same time, and a plastic processed product that can be easily pulverized can be obtained. It is an object of the present invention to provide a method for treating plastic, and a solid fuel and ore reducing agent obtained by the treatment method.

  In the course of studying various methods to achieve the above-mentioned purpose, the present inventors have heated a plastic to a temperature of 150 ° C. or higher, so that a part of the plastic bond is cut by heat, or The entanglement of the plastic molecular chain is loosened, and after heating as described above, it is possible to obtain a processed plastic product that is easy to grind by removing low-boiling components such as plastic degradation products and plasticizers in the plastic. I found out.

In addition, when two or more kinds of different types of plastics are used in combination, the different types of plastics are melted and mixed in the heat treatment process, the polymer chain arrangement becomes irregular, and the processed product becomes brittle. It was found that an easy-to-process plastic product can be obtained.
Furthermore, according to the present invention, dehydrochlorination can be performed at the same time in the heat treatment process, and chlorine compounds such as hydrogen chloride can be removed from the treated plastic product in the removal process of the low boiling point components. There is no generation of dioxin or hydrogen chloride gas when used.

That is, the first invention is a plastic processing method characterized in that after a plastic is heat-treated at a temperature of 150 ° C. or higher, low-boiling components are removed, cooled and solidified.
According to a second aspect of the present invention, there is provided a plastic processing method characterized in that after the plastic is heat-treated at a temperature of 150 ° C. or higher, low-boiling components are removed, cooled and solidified, and then pulverized.
In the first and second inventions described above, the treated product obtained by removing the low boiling point component is cooled to 100 ° C. or less within 10 minutes after the start of cooling from the treatment temperature at the time of removing the low boiling point component. It is preferable to solidify.

In the first and second inventions described above, the plastic is preferably a chlorine-containing plastic.
In the first and second inventions described above, the plastic is more preferably a mixture containing two or more types of plastics other than chlorine-containing plastics. More preferably, the mixture containing two or more kinds of plastics is waste plastic and / or container packaging material.

Furthermore, in the first and second inventions described above, it is preferable to use a distillation method as the method for removing the low-boiling components. Further, as the distillation method, the atmospheric pressure of the object to be treated ≦ (large It is more preferable to use a vacuum distillation method under a pressure condition of atmospheric pressure-500 Torr.
Furthermore, in the first invention and the second invention described above, after heat-treating the plastic at a temperature of 150 ° C. or higher and / or after removing low-boiling components, insoluble matter in the treated product is removed, Then, it is more preferable to cool and solidify.

A third invention is a solid fuel which is a plastic processed product obtained by the plastic processing method of the first invention and the second invention described above.
4th invention is the reducing agent for ore which is a plastic processing thing obtained by the processing method of the plastic of the above-mentioned 1st invention and 2nd invention.
The fifth invention includes a heat treatment step for heat-treating plastic at a temperature of 150 ° C. or higher, a low-boiling component removal step for removing low-boiling components, and cooling and solidification to obtain a lump of a solidified plastic product after cooling. It is a manufacturing method of the plastic processed material characterized by performing a process sequentially.

In the fifth invention described above, the cooling and solidifying step may reduce the treated product after the removal of the low boiling point component to 100 ° C. or less within 10 minutes after the start of cooling from the treatment temperature of the removal step of the low boiling point component. It is preferably a step of cooling and obtaining a lump of solid plastic processed material.
In the fifth aspect described above, it is preferable to perform an insoluble matter removing step for removing insoluble matter after the heat treatment step and / or after the low boiling point component removing step.

In the fifth aspect, the plastic is preferably a mixture of two or more different plastics other than the chlorine-containing plastic, and the two or more different plastic mixtures are waste plastic and / or Or it is preferable that it is a container packaging material.
In the fifth aspect of the invention, it is preferable to perform a pulverizing step of pulverizing the lump of the plastic processed material into a predetermined size following the cooling and solidifying step.

  Moreover, in 5th invention, it is preferable to give the said crushing process which grind | pulverizes the said lump of the plastic processed material to a predetermined magnitude | size, and it is set as the reducing agent for ores, or a solid fuel.

According to the present invention, various problems in the conventional method of directly pulverizing raw plastic are greatly improved.
That is, according to the present invention, the following excellent effects (1) to (5) can be obtained.
(1): For example, direct pulverization of plastic into 1 to 2 mm square becomes unnecessary, and preliminary pulverization to about 10 cm square is sufficient.

(2): The processed plastic product obtained by cooling and solidification is brittle and very easy to pulverize.
(3): Film-like and fiber-like plastics can be processed simultaneously with other plastics.
(4): Chlorine-containing plastics such as polyvinyl chloride can be treated at the same time.

(5): The processed plastic product obtained by the method of the present invention is excellent in grindability, can obtain fine powders substantially free of chlorine, and is used as a non-polluting fuel, reducing agent, etc. excellent in combustibility. be able to.
Further, according to the present invention, since continuous processing can be performed, it is not necessary to use a complicated and expensive apparatus, and mass processing is possible if a large reaction vessel is used, which is excellent in economic efficiency. ing.

Hereinafter, the present invention will be described in more detail in the order of the plastic according to the present invention, a heat treatment step, a low boiling point component removal step, an insoluble matter removal step, a cooling, a solidification step, and a pulverization step.
〔plastic:〕
Examples of plastics targeted by the present invention include, in addition to virgin plastics, waste plastics and container packaging materials contained in municipal waste, industrial waste, etc., and waste plastics generated in the process of dismantling electrical products, automobiles, etc. Is done.

  Specifically, polyolefins such as polyethylene and polypropylene, polyvinyl chloride, polystyrene, polyethylene terephthalate, polycarbonate, nylon, and other thermoplastic resins and thermosetting resins are all applicable. Any one of these can also be used, and two or more can be used in combination.

In the method of the present invention, it is not necessary for all the plastics to be in a molten and low molecular weight state, and some infusible material such as a thermosetting resin remains in the obtained solid fuel. As long as there is no significant obstacle to crushing or the like.
In the present invention, by using different types of plastic mixtures other than chlorine-containing plastics, different types of plastics are melted and mixed in the heat treatment step to be described later, the polymer chain arrangement becomes irregular, and the resulting plastic treatment The material becomes brittle, and the plastic processed material becomes easier to grind. The different types of plastic mixture are preferably different types of plastics other than chlorine-containing plastics.

In particular, according to the present invention, a halogen element such as chlorine contained in the plastic becomes a hydrogen halide such as hydrogen chloride during the treatment, which facilitates separation, and therefore contains chlorine such as polyvinyl chloride and polyvinylidene chloride. Chlorine-containing plastics may be included.
Therefore, according to the present invention, it is not necessary to sort out waste plastic, which is also extremely advantageous.

That is, when the treatment is performed according to the method of the present invention, a treated plastic material substantially containing no halogen element such as chlorine can be obtained.
In addition, the shape and size of the plastic used in the present invention may be roughly pulverized, and a size of about 10 cm square is sufficient, and general waste plastic does not need to be crushed again and remains in a recovered state. The film, sheet, and fiber plastics can be processed as they are.

Heating is easier when finely crushed, but the cost of crushing increases accordingly.
[Heat treatment process:]
The method for heating the plastic to a temperature of 150 ° C. or higher is not particularly limited.
That is, any method may be used, such as a method of simply heating a container containing plastic or a method of mixing a plastic and a high-temperature medium in the container.

When using a high temperature medium, a hot air, hot sand, etc. are illustrated as a high temperature medium.
When a solid high-temperature medium such as hot sand is used, a solid-liquid separation step such as a sedimentation separation method or a filtration method may be incorporated in the subsequent step.
The processing temperature is 150 ° C or higher.
By heating the plastic to a temperature of 150 ° C or higher, it is thought that some of the plastic bonds are broken by heat, and the entanglement of the plastic molecular chains is loosened, reducing the strength of the solids obtained after cooling. Furthermore, when different types of plastics are melted and mixed, the arrangement of the polymer chains becomes irregular, and the resulting processed plastic product becomes brittle and is easily pulverized.

When the processing temperature is less than 150 ° C, the hardness of the plastic processed product obtained after cooling is almost the same as that of the original plastic, and it is difficult to pulverize. The higher the processing temperature, the more the bond breakage occurs. It is considered that the pulverizability of the processed plastic product obtained after cooling is improved.
On the other hand, when the treatment temperature is too high, the yield of the solid after cooling decreases due to gasification or oiling of the plastic.

Therefore, the treatment temperature is defined as 150 ° C. or higher, but the upper limit is preferably 450 ° C., more preferably 200 to 400 ° C., and still more preferably 250 to 380 ° C.
Although plastics also depend on the composition, it is in a molten state at about 140 ° C. or higher. Preferably, if it is stirred and mixed at this time, the homogeneity of the obtained substance is increased, and the reduction in toughness is promoted. The plastic product obtained after cooling can be pulverized more easily.

After raising the temperature of the plastic to 150 ° C. or higher, it is preferable to maintain the temperature at 150 ° C. or higher for a certain time.
A longer retention time is preferable because dehydrochlorination can be performed reliably and the processed plastic product obtained after removal of low-boiling components becomes brittle. However, if the retention time is too long, the decomposition and gasification of the plastic progresses, which is the target. Problems such as a decrease in the yield of solids and a decrease in the processing capacity of the equipment arise.

The preferred holding time is 10 minutes to 6 hours, more preferably 20 minutes to 3 hours.
During the heat treatment, stirring and bubbling using air or an inert gas are preferable because dehydrochlorination is performed efficiently.
[Low Boiling Component Removal Process:]
After completion of the heat treatment described above, the low-boiling components are removed from the plastic and then cooled to obtain a lump of plastic-treated product.

In this low boiling point component removing step, low boiling point components such as a plasticizer, a reaction product such as hydrogen chloride in the plastic, and a decomposition product of the plastic are removed, and the pulverizability of the obtained plastic processed product is improved.
In addition, if a liquid component remains at a normal temperature in the processed plastic product, agglomeration may occur after pulverization or the pulverizability may be reduced. Therefore, the low boiling point component is removed.

Removal of the low-boiling components can be performed by distillation, drying or the like.
In the case of performing distillation, simple simple distillation is possible, and either a batch method or a continuous method may be used.
In any case, the pitch-shaped pot residue obtained after distillation can be extracted by any method and cooled to obtain a target plastic processed product.

The distillation temperature is preferably 150 to 400 ° C.
The distillation temperature is more preferably 200 to 400 ° C, still more preferably 250 to 380 ° C.
As the distillation method, either atmospheric distillation or vacuum distillation may be used, but vacuum distillation is preferable because of its high removal efficiency of low-boiling components, and the atmospheric pressure of the object to be treated ≦ (atmospheric pressure−500 Torr). It is more preferable to use the vacuum distillation method in

When carrying out by a drying method, it is possible to use a method such as storing in a container of any size and processing in a kiln.
The processing temperature in the case of the drying method is preferably 150 to 400 ° C.
The treatment temperature in the case of the drying method is more preferably 200 to 400 ° C, and further preferably 250 to 380 ° C.

In the present invention, it is also possible to remove low-boiling components by spray drying.
In this case, it is preferable to spray a plastic having a temperature of 150 to 400 ° C.
If the temperature of the low boiling point removal process is too low, it will be difficult to remove the low boiling point component. Conversely, if the temperature is too high, the gasification and oiling of the plastic will occur and the yield of the solid after cooling will decrease. .
The low boiling point component removed in this step is a low molecular weight component obtained by decomposing the plastic, an additive such as a plasticizer in the plastic, or a reaction product such as hydrogen chloride.

The temperature at the time of removing the low boiling point component may be the same as or different from the temperature in the heat treatment step.
It is preferable that the temperature at the time of removing the low boiling point component is higher than the temperature in the heat treatment step because the low boiling point component is easily removed.
[Insoluble matter removal step:]
In the present invention, it is more preferable to remove insolubles from the treated product after the heat treatment step or after the low boiling point component removal step or after both steps.

When a solid-liquid separation step such as a centrifugal separation method, a stationary separation method, or a filtration method is incorporated as a subsequent step of the heat treatment step and / or a low boiling point component removal step, glass, metal It can be processed even if it contains inorganic materials such as paper, etc., for example, bottles with metal caps attached can also be processed.
Further, by removing insolubles, inorganic substances such as metals are removed, and not only pulverization in the subsequent process is facilitated, but also a plastic treated product having a low chlorine content is obtained.

That is, when chlorine-containing plastics such as polyvinyl chloride are dehydrochlorinated, carbides are likely to be generated, and the carbides are likely to contain chlorine components. By removing the insoluble matter in the subsequent step of the removal step, the chlorine content in the obtained plastic processed product can be further reduced.
[Cooling and solidification process:]
The processed product after the removal of the low boiling point components is cooled to obtain a solidified plastic processed product.

The cooling method and the cooling rate are not particularly limited. However, the faster the cooling rate, the easier the plastic processed product obtained is pulverized.
In the present invention, it is preferable that the cooling time from the temperature at the time of removing the low boiling point component to a temperature of 100 ° C. or less is within 10 minutes from the start of cooling.
[Crushing process:]
In the present invention, it is preferable to pulverize the lump of the cooled and solidified plastic product into a predetermined size.

Grinding at this stage is much easier than grinding untreated plastic.
Therefore, it can be pulverized by any type of pulverizer, and for example, a jaw crusher, a roll crusher, a ball mill, a centrifugal mill or the like can be used.
The particle size after pulverization may be determined according to the object of use, and if the particle size is adjusted to a predetermined particle size, for example, ore reducing agent such as iron ore, that is, raw fuel such as reducing agent for blast furnace, It can be used as combustion fuel for boilers and kilns.

  Furthermore, since the plastic processed material obtained by the processing method of the present invention has excellent pulverizability, it can be used as a solid fuel and a reducing agent that are fine powder and excellent in combustibility, in addition to the above-described uses.

Hereinafter, the present invention will be specifically described based on examples.
Example 1
Polyethylene (film-like), polypropylene (plate-like), polystyrene (plate-like), polyethylene terephthalate (fiber-like) cut into about 10cm square or about 10cm length each in a 5L stainless steel reactor 300 g was charged, and the temperature was raised by the heater on the outer wall of the reactor.

In addition, the component analysis value of the mixture in the said compounding quantity of said 4 types of plastics was C: 81 wt%, H: 11 wt%, O: 8 wt%.
When the temperature in the reactor exceeded 180 ° C after the start of temperature increase, most of the plastic melted, so stirring was started. Finally, the temperature was increased to 330 ° C and held at that temperature for 2 hours.
Next, vacuum distillation at 50 Torr (absolute pressure) was carried out for 2 hours at the same temperature, and then cooled to room temperature to obtain a brown solid.

When 5 g of the resulting brown solid was charged into a rotary blade crusher and pulverized, it was easily pulverized, and a finely divided solid having an average particle diameter of 1 mm was obtained with a pulverization time of 20 seconds.
Table 1 shows the test results such as the type, shape, and dimensions of the plastic used in this example, the input amount to the reactor (addition amount), other processing conditions, the component analysis value of the obtained lump, and the pulverization test result. Shown in

(Reference Examples 1 to 11, Comparative Examples 1 and 2)
Various plastics with different blending amounts from Example 1 (component analysis values of the mixture C: 73 wt%, H: 9 wt%, O: 7 wt%, Cl: 11 wt%), heat treatment conditions, conditions of de-low boiling point components, etc. A processed plastic product was obtained in the same manner as in Example 1 except that was changed.
The obtained massive solid was pulverized using the same pulverizer as in Example 1, and the pulverization time and average particle diameter were measured.

Test results such as plastic types, shapes, dimensions used in the reference examples and comparative examples, the amount input to the reactor (added amount), other processing conditions, component analysis values of the resulting mass, and pulverization test results Table 1 shows.
(Example 2)
Polyvinyl chloride (component analysis values C: 41 wt%, H: 3 wt%, O: 0 wt%, Cl: 56 wt%) was obtained in the same manner as in Example 1 under the conditions shown in Table 1. The bulk plastic processed product was evaluated.

Table 1 shows the component analysis values and the pulverization test results of the obtained mass.
(Reference Example 12)
In Reference Example 1, the processed product after removal of the low-boiling components was subjected to hot filtration at the same temperature as that at the time of removing the low-boiling components to remove the solid insoluble matter. After being obtained, it was cooled and solidified.

Table 1 shows the component analysis values and the pulverization test results of the obtained mass.
(Comparative Example 3)
Polyethylene (film-like), polypropylene (plate-like), polystyrene (plate-like), polyvinyl chloride (plate-like), polyethylene terephthalate (fiber-like) cut into about 1cm square or about 10cm long, 10g each It was charged in a rotary blade type pulverizer and pulverized.

However, film-like and fibrous plastics were entangled with the rotary blade and could not be crushed.
From the above results, the processed plastic product obtained by the treatment method of the present invention is easy to grind and has a low chlorine content, and is intended for use as a solid fuel for boilers and kilns, a reducing agent for iron ore, etc. It turns out that it is excellent.

Claims (16)

  A method for treating plastic, comprising: heat-treating plastic at a temperature of 150 ° C. or higher, then removing low-boiling components, and cooling and solidifying.   2. The plastic processing method according to claim 1, wherein after cooling and solidification, pulverization is performed.   3. The treated product obtained by removing the low-boiling components is cooled and solidified to 100 ° C. or less within 10 minutes after the start of cooling from the treatment temperature at the time of removing the low-boiling components. Plastic processing methods.   The plastic processing method according to claim 1, wherein the plastic is a mixture containing two or more kinds of plastics other than chlorine-containing plastics.   The method for treating plastic according to claim 4, wherein the mixture containing two or more kinds of plastics is waste plastic and / or container packaging material.   The plastic processing method according to claim 1, wherein the plastic is a chlorine-containing plastic.   7. The plastic is heat-treated at a temperature of 150 ° C. or higher and / or after removing low-boiling components, and then insoluble matter in the treated product is removed, and then cooled and solidified. The processing method of the plastic in any one of.   A solid fuel which is a processed plastic product obtained by the plastic processing method according to claim 1.   A reducing agent for ore, which is a processed plastic product obtained by the plastic processing method according to claim 1.   A heat treatment process for heat-treating plastic at a temperature of 150 ° C. or higher, a low-boiling component removal process for removing low-boiling components, and a cooling and solidification process for cooling to obtain a lump of solid plastic processed material are sequentially performed. A method for producing a processed plastic product.   In the cooling and solidification step, the processed product after the removal of the low boiling point component is cooled to 100 ° C. or less within 10 minutes from the treatment temperature of the low boiling point component removal step to obtain a solidified plastic product lump. It is a process, The manufacturing method of the plastic processed material of Claim 10 characterized by the above-mentioned.   The method for producing a processed plastic product according to claim 10 or 11, wherein a removal step of insoluble matter is performed after the heat treatment step and / or after the removal step of the low-boiling-point component.   The method for producing a processed plastic product according to any one of claims 10 to 12, wherein the plastic is a mixture of two or more kinds of plastics other than chlorine-containing plastic.   The method for producing a processed plastic product according to claim 13, wherein the mixture of two or more kinds of different plastics is waste plastic and / or container packaging material.   The method for producing a plastic processed product according to any one of claims 10 to 14, wherein a pulverizing step of pulverizing the lump of the plastic processed product into a predetermined size is performed following the cooling and solidifying step.   The method for producing a processed plastic product according to claim 15, wherein the crushing step is performed to obtain a reducing agent for ore or a solid fuel.