JP2001354801A - Method for removing halogen in waste synthetic resins - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for removing a halogen in a waste synthetic resin capable of preventing complication of a process and a rise in an energy cost and reducing a halogen. SOLUTION: This method for removing a halogen of a waste synthetic resin comprises a first-stage dehalogenating process (A) for heating and dehalogenating a halogen-containing waste synthetic resin, a granulation process (B) for flowing a melt obtained by heating down and blowing an inert gas on the flow to give a granule and a second-stage dehalogenating process (C) for cleaning a granule.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for removing halogen from various waste plastics (waste synthetic resins) generated in, for example, general households.

[0002]

2. Description of the Related Art In recent years, disposal of synthetic resin waste generated as industrial waste or general waste has become a social problem.
As a corresponding technique, it has been proposed to recycle waste synthetic resins as an auxiliary fuel in a metallurgical furnace such as a blast furnace, a coke oven, or a boiler or a cement kiln.

[0003] PVC that contains chlorine is regarded as a troublesome substance in reusing waste synthetic resins as fuel.
(Polyvinyl chloride) and PVDC (polyvinylidene chloride)
Or various synthetic resins containing a halogen-based additive (eg, a bromine-containing flame retardant). That is, when a regenerated fuel obtained from such a halogen-containing synthetic resin is burned in the above metallurgical furnace or the like, halogen or hydrogen halide (hereinafter, simply referred to as halogen) is generated, and refractories or peripheral equipment of the metallurgical furnace or the like is produced. There is a problem of corrosion.

[0004] Therefore, waste synthetic resins are preliminarily dechlorinated. As the dechlorination technology, a method of heating and melting with a rotary kiln furnace, a thermal decomposition reaction device or the like (Japanese Patent Laid-Open Nos. 10-259273 and 8-120).
285) has been proposed.

[0005]

However, in the case of the above-mentioned conventional proposed method of heating and melting, it is effective for reducing organic chlorine, but for inorganic salts such as NaCl which are difficult to be thermally decomposed, For example, about 4% chlorine content is about 0.8
%, And it is difficult to reduce it to a sufficient level.

In view of this, since the above-mentioned inorganic salts such as NaCl are water-soluble, a method of reducing the inorganic powder and washing the fine powder can be considered. In the case of the fine powder washing method, the inorganic salt is mechanically pulverized into fine powder. Since a pulverizing step and a washing step of washing the fine powder to remove inorganic salts are separately required, there are drawbacks in that the steps become complicated and the energy cost increases.

SUMMARY OF THE INVENTION The present invention has been made to solve such problems of the prior art. Halogen removal from waste synthetic resins capable of reducing the halogen by preventing the process from becoming complicated and increasing the energy cost. The aim is to provide a method.

[0008]

The method for removing halogen from waste synthetic resins according to claim 1 is a method for removing halogen from halogen-containing waste synthetic resins. Performing a dehalogenation treatment of the step;
While flowing down the melt obtained by the heating,
A step of spraying an inert gas to the flow to granulate it, followed by washing and performing a second-stage dehalogenation treatment.

In the method for removing halogen of the present invention,
When the halogen-containing waste synthetic resin is heated and subjected to the first-stage dehalogenation treatment, the organic halogen is thereby removed. After that, the melt obtained by heating is allowed to flow down,
An inert gas is sprayed on the flow to granulate it,
When the particulate matter is washed, a second stage dehalogenation treatment for removing a water-soluble inorganic halogen such as NaCl is performed.
Therefore, the halogen can be reduced to a low level without the necessity of the pulverizing step, so that the step can be simplified and the energy cost can be reduced.

The method for removing halogen from waste synthetic resins according to claim 2 is a method for removing halogen from halogen-containing waste synthetic resins, wherein the waste synthetic resins are heated to remove the halogen in the first stage. A step of performing a treatment, and a step of performing a second-stage dehalogenation treatment in which the melt obtained by the heating is caused to flow down, and the flow is sprayed with water to be granulated.

In the method for removing halogen according to the present invention,
When the halogen-containing waste synthetic resin is heated and subjected to the first-stage dehalogenation treatment, the organic halogen is thereby removed. After that, the melt obtained by heating is allowed to flow down,
When water is sprayed on the stream to granulate it,
A second stage dehalogenation treatment for removing water-soluble inorganic halogen such as Cl is performed. Therefore, since the melt after the heating is sprayed with water to be granulated, a pulverizing step and a washing step are not required, so that the steps can be simplified and the energy cost can be reduced.

In the method for removing halogen from waste synthetic resins according to the second aspect, an inert gas may be blown in addition to water when performing the second-stage dehalogenation treatment.

In such a case, since an inert gas is blown together with water to the flow of the melt,
The particle size of the granular material can be reduced and sized.

[0014]

Embodiments of the present invention will be specifically described below with reference to the drawings.

FIG. 1 is a process diagram showing a method for removing halogen from waste synthetic resins according to one embodiment of the present invention.

The halogen removing method of the present embodiment comprises a first stage dehalogenation treatment step (A) for heating halogen-containing waste synthetic resins to dehalogenate them, flowing down the melt obtained by heating, The method includes a granulation step (B) of spraying an inert gas to the flow to obtain granules, and a second-stage dehalogenation step (C) of washing the granules.

FIG. 2 is a schematic front view showing a dehalogenation furnace for performing the first-stage dehalogenation treatment step (A) and a granular processing apparatus for performing the granulation step (B).

This dehalogenating furnace has a cylindrical body 1 having a circular cross section.
A hopper 2 provided on the cylindrical body 1 and storing the crushed material 10, a screw 3 provided inside the cylindrical body 1 and rotating, and an electric motor 4 connected to a rotating shaft of the screw 3.
And a heater 5 provided outside the cylindrical body 1.

The crushed material 10 in the hopper 2 is supplied into the cylindrical body 1 from the inlet 1a, is sent to the tip side by the screw 3, and is heated by the heater 5 at the time of being sent.
a. As a result, a first-stage dehalogenation treatment for removing the organic halogen component from the halogen-containing waste synthetic resins is performed. Further, with heating, Cl ₂ , HCl,
A cracked gas containing low molecular hydrocarbons and the like is generated, and the cracked gas is sent to a first storage tank 7 via a pipe 6 connected to the cylinder 1 and further to a second storage tank 9 via a pipe 8. Sent.
Of the cracked gas introduced into the first storage tank 7, low-boiling organic compounds, for example, low-molecular hydrocarbons and low-molecular aromatic compounds are liquefied and stored in the tank, and are stored in the second storage tank 9 in advance. Water is stored, and the halogen-based inorganic component in the decomposition gas is dissolved in the water, for example, hydrochloric acid is produced. The decomposed gas from which the organic and inorganic substances have been removed is discharged to the exhaust pipe 14.
And after being subjected to various detoxification treatments as required, is released into the atmosphere. On the other hand, the melt 10 a that has been subjected to the first-stage dehalogenation treatment falls from the outlet 1 b of the cylindrical body 1.

The above-mentioned granular processing apparatus is provided with:
0a is provided with a frame 11 supplied from the inlet 11a to the inside in a flowing state, and a blower 12 for blowing an inert gas, for example, nitrogen gas, to the melt 10a is provided on a side of the frame 11, and an outlet of the frame 11 is provided. A storage box 13 is provided below 11b. When the position of the outlet 1b of the cylindrical body 1 is different from the position of the inlet 11a of the frame 11, a gutter provided with a heating function is provided so as to keep the melt 10a warm, and the melt 10a discharged from the outlet 1b is provided. May be sent to the entrance 11a via a gutter.

The nitrogen gas blown from the blower 12 gives a high pulverizing energy to the melt 10a flowing down, atomizes and cools the melt flow by an atomizing action, and scatters and drops as particulate matter. The granular material 10b thus obtained falls from the outlet 11b of the frame 11 and is stored in the storage box 13.

Thereafter, the granular material 1 stored in the storage box 13 is
Ob is washed, for example, with water. By this washing, N
A second stage dehalogenation treatment for removing water-soluble inorganic halogens such as aCl is performed to produce particulates in which halogens have been reduced to low levels.

Therefore, according to the present embodiment,
The halogen-containing waste synthetic resin is heated to perform a first-stage dehalogenation treatment. At this time, an inert gas is blown against the molten material in a molten state to granulate the molten material, and the granular material is removed. Since the second stage dehalogenation treatment is performed by washing with water, a mechanical pulverizing step is not required, so that the step can be simplified and the energy cost can be reduced.

By appropriately adjusting the particle size of the thus-obtained granular material, it can be recycled directly as an auxiliary fuel in a metallurgical furnace such as a blast furnace, a coke oven, or a boiler or cement kiln. Becomes possible. Further, even when recycled, the particulate matter has a low halogen component, so that the occurrence of corrosion in a metallurgical furnace or the like can be suppressed.

[0025]

FIG. 3 is a diagram showing a change in chlorine concentration according to the above-described embodiment (Example) and a change in chlorine concentration according to a comparative example. The vertical axis indicates the amount of chlorine (wt%).

In the comparative example, a crushed product of waste synthetic resin was subjected to heat dry distillation (first-stage dechlorination treatment), and then the condensed product was mechanically pulverized, for example, to a pulverized product having a particle size of about 100 μm. This was washed (second-stage dechlorination treatment).

On the other hand, in the example, heating (first-stage dechlorination treatment) and washing (second-stage dechlorination treatment) were performed on the crushed waste synthetic resin. As the crushed material, for example, a lump-shaped material having a major axis length of 25 mm or less and a rod-shaped material having a length dimension of 200 mm or less were used. The granulated product finally obtained had a particle size of 10 mm or less suitable for being injected as a fuel into a metallurgical furnace such as a blast furnace. As can be understood from FIG. 3, the chlorine concentration was finally reduced to 0.2 wt% in the case of the embodiment of the present invention in which the process was simplified, as in the case of the comparative example.
However, when the chlorine concentration is further reduced according to the present invention, it is preferable to reduce the particle size of the granulated material to a smaller value, for example, 300 μm or less by increasing the blowing force of the inert gas.

In the above-described embodiment, the melt is granulated by blowing an inert gas and stored in the storage box 13, and then the cleaning is performed. That is, the granulation step (B) and the second stage dehalogenation are performed. Although halogen is removed in a state where the treatment step (C) is clearly separated, the present invention is not limited to this. For example, the melt is granulated by blowing an inert gas, water is placed in a container at the drop position of the granulated material, and the granulated material solidifies when washed with the water. It may be made to be granular.

In the above-described embodiment, atomization by an inert gas has been described. However, the present invention is not limited to this, and the melt may be granulated by an atomization method in which water is sprayed on a falling melt. In this case, washing can be performed at the same time as granulation of the melt, and not only a mechanical crushing step but also a washing step become unnecessary, so that the step can be further simplified and the energy cost can be further reduced. .

Further, in the present invention, a combination of water atomization and gas atomization, that is, water and an inert gas may be simultaneously blown. In such a case, there is an advantage that the particle size of the granular material can be further reduced and the particle size can be reduced.

In the above-described embodiment, a melt-extrusion type dehalogenation furnace having a screw is used as an apparatus for performing the first dehalogenation treatment. However, the present invention is not limited to this. As long as it can be performed, other types, for example, a dehalogenation furnace including a batch type heating and melting furnace can be used. At this time, depending on the type of the dehalogenation furnace to be used, the waste synthetic resin as a raw material can be pulverized to an appropriate particle size, or the waste synthetic resin can be used without being pulverized.

In the above-mentioned embodiments, the applicable synthetic resin is not specified, but the present invention can be applied to general synthetic resins which melt by heating.

[0033]

As described above in detail, in the case of the present invention, the halogen-containing waste synthetic resin is subjected to the first-stage dehalogenation treatment by heating, and the melt obtained by heating is converted into an inert gas. When the second step of dehalogenation treatment is performed by washing the granules and spraying the granules, organic and inorganic halogens can be removed to a low level, and a pulverizing step is not required. In addition, the process can be simplified and the energy cost can be reduced. Further, in the present invention, since the melt can be granulated by spraying water, it is possible to granulate the melt and simultaneously perform the second-stage dehalogenation treatment by washing, Since the pulverizing step and the washing step are not required, the steps can be further simplified and the energy cost can be further reduced. Further, in the present invention,
Since water and inert gas can be sprayed at the same time, the process can be further simplified and the energy cost can be further reduced. In addition, the particle size of the granulated material for fuel can be further reduced and sized. Can be

[Brief description of the drawings]

FIG. 1 is a process diagram showing a method for removing halogen from waste synthetic resins according to an embodiment of the present invention.

FIG. 2 is a schematic front view showing a dehalogenation furnace for performing a heating step of the method of the present invention and a granular processing apparatus for performing a granulation step.

FIG. 3 is a diagram showing a change in chlorine concentration according to an embodiment of the present invention and a change in chlorine concentration according to a comparative example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Cylindrical body 2 Hopper 3 Screw 5 Heater 10 Crushed material 11 Frame 12 Blower

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Masanori Shimizu 1 Kanazawa-cho, Kakogawa-shi, Hyogo Prefecture Kobe Steel Works Kakogawa Works F-term (reference) 4D004 AA08 AB06 AC04 BA03 CA24 CA32 CB32 CB37 4F301 AA16 AA17 AC17 BA17 BA21 BB10 BD02 BD48 BE01 BE12 BE16 BF16 BF20 BF29 CA09 CA25 CA42 CA43 CA52 CA68

Claims (3)

[Claims] 1. A method for removing halogen from a halogen-containing waste synthetic resin, comprising: a step of heating the waste synthetic resin to perform a first-stage dehalogenation treatment; and a melt obtained by the heating. Along with the
A step of spraying an inert gas to the stream to granulate the stream, followed by washing and performing a second-stage dehalogenation treatment. 2. A method for removing halogen from a halogen-containing waste synthetic resin, comprising: a step of heating the waste synthetic resin to perform a first-stage dehalogenation treatment; and a melt obtained by the heating. Along with the
Performing a second-stage dehalogenation treatment of spraying water on the stream to granulate the waste stream. 3. The method for removing halogen from waste synthetic resins according to claim 2, wherein an inert gas is also blown in addition to water when performing the second-stage dehalogenation treatment.