JP2002306926A - Method for recovering hydrochloric acid from chlorine- containing resin - Google Patents

Abstract

PROBLEM TO BE SOLVED: To dechlorinate a chlorine-containing resin and to stably recover hydrochloric acid with high concentration and high purity from the gas generating by the above treatment. SOLUTION: The method includes a process (A) to preliminarily treat a chlorine-containing resin for dechlorination, a process (B) to thermally decompose the chlorine-containing resin after the process (A) by heating to desorb the chlorine content in the resin as hydrogen chloride gas, a process (C) to combust the gas containing hydrogen chloride discharged from the process (B) to remove the organic component in the gas and a process (D) to recover hydrogen chloride in the gas from the process (C) as hydrochloric acid. Because the organic component in the gas can be almost completely removed by the process (C), hydrochloric acid with high purity can be recovered.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for dechlorinating a chlorine-containing resin and recovering hydrochloric acid from a gas generated therefrom.

[0002]

2. Description of the Related Art In recent years, plastics have been rapidly increasing as industrial wastes and general wastes, and their disposal has become a major social problem. Above all, chlorine-containing resin (mainly vinyl chloride) used for agricultural sheets and resin-coated electric wires
As a result, hydrogen chloride gas generated during the incineration process may cause facility problems such as damaging the wall of the incinerator. In addition, there is also a problem that harmful substances such as dioxin are generated when the chlorine-containing resin is burned. For this reason, at present, most of the chlorine-containing resins are dumped at landfill sites. However, the dumping of plastic causes the ground of the landfill to deteriorate, and it is not preferable in terms of environmental measures.In addition, shortage of land for landfilling is becoming a social problem in recent years. There is an urgent need to establish a large-scale processing method.

To solve such a problem, Japanese Patent Application Laid-Open No.
JP-A No. 0285 and JP-A-5-245463 disclose an extruder-type pyrolysis reaction apparatus for pyrolyzing mixed waste plastics containing vinyl chloride. This extruder-type pyrolysis reaction device is an external heat type, and is a device capable of recovering chlorine with high efficiency. JP-A-51-36287 discloses a method of recovering a useful substance from a thermoplastic resin (such as vinyl chloride) using an externally heated rotary kiln. Further, Japanese Patent Application Laid-Open No. 8-278015 discloses a method of recovering chlorine from a chlorine-containing resin by a direct heating rotary kiln, using sand slag as a solid heat medium.

[0004]

However, these prior arts have the following problems in recovering hydrochloric acid from a gas containing hydrogen chloride generated by dechlorination. Since the gas containing hydrogen chloride generated by the dechlorination treatment contains an organic component generated by the decomposition of a plasticizer or the like, this organic component is mixed with the recovered hydrochloric acid and can be used for industrial use and the like. It is difficult to recover high purity hydrochloric acid. In addition, a large cost is required to recover the organic components from hydrochloric acid. In order to efficiently recover hydrochloric acid, it is essential to remove water.However, film-based waste plastics such as agricultural vinyl sheets have a high rate of adhesion of water and inorganic substances other than resin.
For example, the amount of adhering moisture may be as high as 50% by mass and the amount of inorganic substances may be as high as 20% by mass relative to the whole. Therefore, when processing such waste plastic with a large amount of attached moisture,
High-concentration hydrochloric acid cannot be efficiently recovered.

Accordingly, an object of the present invention is to solve such problems of the prior art and to dechlorinate a chlorine-containing resin,
An object of the present invention is to provide a hydrochloric acid recovery method capable of stably recovering high-purity and high-concentration hydrochloric acid from the generated gas.

[0006]

The features of the present invention for solving such a problem are as follows. [1] A step (A) of pre-treating a chlorine-containing resin for a dechlorination treatment, and the chlorine-containing resin subjected to the step (A) is thermally decomposed by heating to remove chlorine content in the resin into hydrogen chloride gas. (B) desorbing as a step, a step (C) of burning the gas containing hydrogen chloride discharged from the step (B) to remove organic components contained in the gas, and a step (C) A) recovering hydrogen chloride in the gas having passed through the step (D) as hydrochloric acid.

[2] In the method for recovering hydrochloric acid of the above [1], between the steps (B) and (C), a step (E) of rapidly cooling the high-temperature gas containing hydrogen chloride which has passed through the step (B). A method for recovering hydrochloric acid from a chlorine-containing resin, comprising: [3] In the method for recovering hydrochloric acid according to the above [1] or [2], the chlorine-containing resin to be dechlorinated comprises a film-like chlorine-containing resin, and the step (A) comprises a step of crushing the film-like chlorine-containing resin. (a1), a step (a2) of drying the film-like chlorine-containing resin after the step (a1), and a step (a3) of reducing the volume of the film-like chlorine-containing resin after the step (a2). A method for recovering hydrochloric acid from a chlorine-containing resin.

[4] In the method for recovering hydrochloric acid according to the above [1] or [2], the chlorine-containing resin to be dechlorinated comprises a solid chlorine-containing resin, and the step (A) comprises crushing the solid chlorine-containing resin. A method for recovering hydrochloric acid from a chlorine-containing resin, comprising a step (a) of treating. [5] In the method for recovering hydrochloric acid of the above [1] or [2], the chlorine-containing resin to be dechlorinated comprises a film-like chlorine-containing resin and a solid chlorine-containing resin, and the step (A) comprises: A step (a1) of crushing the resin, and a step (a2) of drying the film-like chlorine-containing resin after the step (a1);
A step (a3) of reducing the volume of the film-like chlorine-containing resin after the step (a2), and a step (a4) of crushing the solid-state chlorine-containing resin, wherein the chlorine-containing resin having passed through the step (a3) And a method for recovering hydrochloric acid from a chlorine-containing resin, wherein the chlorine-containing resin that has passed through the step (a4) is sent to the step (B) without distinguishing the two.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION In the method for recovering hydrochloric acid of the present invention, a step (A) of pretreating a chlorine-containing resin for dechlorination.
Heating the chlorine-containing resin that has passed through the step (A) to thermally decompose it, thereby desorbing the chlorine content in the resin as hydrogen chloride gas; and removing the chlorine discharged from the step (B). It has a step (C) of removing an organic substance contained in the gas by burning a gas containing hydrogen and a step (D) of collecting hydrogen chloride in the gas passing through this step (C) as hydrochloric acid. . In the step (A), crushing, drying, and volume reduction of the chlorine-containing resin are performed as described later. In the step (B),
For example, by heating a chlorine-containing resin by a rotary kiln type dechlorination treatment apparatus to thermally decompose the resin, chlorine in the resin is desorbed as hydrogen chloride gas. The process
In (C), it is preferable to completely burn the organic components contained in the generated gas in the step (B) and to perform a combustion treatment on the generated gas under conditions such that dioxin is not generated by the combustion. C. or higher, and a burning time: about 2 seconds.

According to the method of the present invention, the organic components can be almost completely removed from the gas containing hydrogen chloride generated by the dechlorination treatment, and high-purity hydrochloric acid can be recovered. Further, by adding a step (E) of rapidly cooling the hot gas after the combustion treatment between the steps (B) and (C), the generation of dioxins in the cooling process of the high-temperature gas is reliably prevented. can do. In the step (E), the hot gas is quenched by a method of spraying excess water or an aqueous solution with respect to the hot gas or a method of blowing the hot gas into the water or the aqueous solution.

When the chlorine-containing resin to be dechlorinated is a film-like chlorine-containing resin, the step (A) is, for example, a step (a1) of crushing the film-like chlorine-containing resin.
And a step (a2) of drying the film-like chlorine-containing resin after the step (a1) and a step (a3) of reducing the volume of the film-like chlorine-containing resin after the step (a2). Become. In the volume reduction step (a3), for example, the resin is softened or melted or semi-melted by frictional heat by stirring or extrusion or external heating, and then solidified to reduce the volume. When the chlorine-containing resin to be dechlorinated is a solid chlorine-containing resin, the step (A)
Is, for example, a step of crushing a solid chlorine-containing resin (a)
Will be provided. By treating in such a more limited form, it is possible to sufficiently reduce the amount of water adhering to the waste plastic film (chlorine-containing resin) having a particularly large amount of adhering water, and to recover a high concentration of hydrochloric acid.

Further, when the chlorine-containing resin to be dechlorinated comprises both a film-like chlorine-containing resin and a solid chlorine-containing resin, the step (A) may be performed, for example, by crushing the film-like chlorine-containing resin. (A1) and a step of drying the film-like chlorine-containing resin after the step (a1)
(a2), a step (a3) of reducing the volume of the film-form chlorine-containing resin after the step (a2), and a step (a4) of crushing the solid-form chlorine-containing resin. (a
The chlorine-containing resin passed through the step 3) and the chlorine-containing resin passed through the step (a4) are sent to the step (B) without distinguishing the two.

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows a processing flow of one embodiment of the present invention, in which the chlorine-containing resin to be dechlorinated is a film-like chlorine-containing resin. In FIG.
1 is a crushing step of a film-like chlorine-containing resin, 2 is a drying step of a film-like chlorine-containing resin, 3 is a volume reduction step,
Is a step of dechlorinating a chlorine-containing resin, 5 is a step of cooling a dechlorinated product (residue of a thermally decomposed resin), 6 is a step of separating a solid heat medium from the dechlorinated product, and 7 is an organic substance in a gas generated in the dechlorination step. 8 is a step of burning and removing components, 8 is a step of rapidly cooling the gas after combustion, 9 is a step of absorbing hydrogen chloride in the gas as hydrochloric acid,
10 is a step of distilling the absorbed hydrochloric acid, 11 is a purification step of removing impurities from the distilled hydrochloric acid, and 12 is the absorption step 9
This is a step of excluding trace amounts of hydrogen chloride in exhaust gas discharged from. When the soil and water content in the film-form chlorine-containing resin is large, a washing step 13 and a drying step 14 may be provided before the crushing step 1. When the dechlorinated resin separated in the separation step 6 has a lump, a crushing step 15 may be provided after the separation step 6.

In the above processing flow, the film-form chlorine-containing resin is subjected to a washing step 13 and a drying step 14 as required, and then crushed in a crushing step 1 to a size that can be supplied to the volume reduction step. . Next, in the drying step 2, moisture in the film-form chlorine-containing resin is removed, and at this time, earth and sand and the like adhering to the film-form chlorine-containing resin are also removed. This drying step 2 involves heating, but this heating is performed at a heating temperature (preferably 150 ° C. or lower) at which dechlorination of the chlorine-containing resin does not occur. In addition, as a method that does not rely on heating, a drying treatment may be performed with a dehydrator using centrifugal force. Further, it is also possible to use a wet crushing device which also performs crushing, separation from inorganic substances and dehydration.
In addition, the sensible heat of the solid heat medium separated from the pyrolysis resin residue in the dechlorination step 4 can be used for drying the chlorine-containing synthetic resin.

The film-form salt dried in the drying step 2
Element-containing resin has a bulk density of 0.1 t / m ³Because it is as low as
The load on the transport means up to the dechlorination step 4 increases. That
Therefore, in the volume reduction step 3, the bulk density is 0.3 to 0.5 t /
m³The volume is reduced to a degree. Reduction of chlorine-containing synthetic resin
As a method for consolidation, for example, the resin is stirred or extruded.
Softening or melting by frictional heat or external heating
Take any method such as solidifying after semi-melting
However, the processing temperature of the resin is the temperature at which the dechlorination reaction does not occur.
It is preferably within the range of degrees.

The chlorine-containing resin thus reduced in volume is subjected to a dechlorination treatment in a dechlorination step 4. This dechlorination treatment is performed by heating the chlorine-containing resin to desorb the chlorine content in the resin as hydrogen chloride gas. Hereinafter, a case where a rotary kiln type dechlorination apparatus is used as the dechlorination apparatus will be described as an example. The elimination reaction of chlorine from the chlorine-containing resin starts at about 250 ° C. and ends at about 350 ° C. In this temperature range, a decomposition reaction of resins other than the chlorine-containing resin also occurs, but the degree is small. For this reason, the temperature of the gas generated at the outlet of the rotary kiln is preferably in a temperature range of about 300 to 350 ° C. in which decomposition of resins other than the chlorine-containing resin is small and chlorine desorption reaction is active. In addition, hydrogen chloride has a large corrosive effect on steel used in the apparatus, and the corrosion rate increases at 150 ° C. or lower and 350 ° C. or higher. Therefore, the temperature of the gas generated at the outlet is preferably in the above-mentioned temperature range of 300 to 350 ° C. in order to appropriately prevent corrosion of the apparatus due to hydrogen chloride, particularly, corrosion of various parts of the inner tube of the kiln.

In order to efficiently and uniformly heat the chlorine-containing resin in the rotary kiln, a solid heat medium is supplied into the rotary kiln together with the chlorine-containing resin. As the solid heat medium (powder and granules), a granular material such as sand may be used. For example, the decomposed pyrolyzed resin residue may be left as it is or partly without being separated from the solid heat medium. When supplied to a furnace such as a blast furnace (especially a melting furnace) as it is, it can be used as a raw material for the furnace as a heat medium, specifically, it can be used as an iron source reducing agent, fuel, auxiliary material, etc. It is preferable to use a granular material. As a result, even if a solid heat medium is contained in the pyrolysis resin residue after the dechlorination treatment, it is used as a reducing agent or fuel for an iron source in a melting furnace or the like as it is or with a part thereof recovered and the remaining remaining. Can be supplied. Granules suitable for such a heating medium include coke breeze, fine ore, sintered powder, and the like.
One or more of these can be used as a solid heat carrier. Further, it is also possible to use the pyrolysis resin residue from which chlorine has been removed as a solid heat medium. It is preferable that the dechlorination apparatus is sealed with an inert gas such as nitrogen so that no air flows into the apparatus, and is operated at a negative pressure so that generated hydrogen chloride does not leak.

The pyrolysis resin residue after the dechlorination treatment in the dechlorination step 4 is cooled in a cooling step 5, and then the solid heat medium is separated from the pyrolysis resin residue in a solid heat medium separation step 6. Done. However, when the solid heating medium is supplied to the melting furnace or the like without being separated from the pyrolysis resin residue as described above, the separation step 6 is omitted. In the separation step 6, only a part of the solid heat medium may be separated from the pyrolysis resin residue. Since the chlorine-containing resin shrinks in the course of the dechlorination treatment and is extremely smaller than the particle diameter before the dechlorination, the separation of the solid heat medium in the separation step 6 is easy. The separation of the solid heat medium can also be performed by a vibrating sieve, trommel sorting, or wind sorting. The separated solid heat medium is returned to the dechlorination step 4 and reused as the solid heat medium. On the other hand, the pyrolysis resin residue is crushed in the crushing step 15 as necessary, and the processing is completed.

The gas generated from the dechlorination step 4 contains a high concentration of hydrogen chloride, but also contains organic components such as hydrocarbons due to the thermal decomposition of the chlorine-containing resin. In order to reduce the purity of the recovered hydrochloric acid, the generated gas is removed by subjecting the generated gas to a combustion treatment in a combustion step 7 to completely burn the organic component. This combustion treatment is desirably a combustion condition in which organic components are completely burned and dioxin or the like is not generated, and it is generally preferable to perform the combustion at a burning temperature of 1100 ° C. or more and a burning time of about 2 seconds.
When the combustion temperature is higher, the combustion time can be shortened.

Further, in order to prevent the generation of dioxins and the like in the course of the temperature reduction of the gas after the combustion processing, the high-temperature gas after the combustion processing is rapidly cooled in a rapid cooling step 8. In the quenching step 8, the hot gas is quenched by a method of spraying excess water or an aqueous solution with respect to the hot gas, a method of blowing the hot gas into the water or the aqueous solution, or the like. The hydrogen chloride absorbed in the water in the quenching step 8 is supplied to the absorbing step 9 by a saturated vapor pressure together with the quenched gas, and is recovered in the absorbing step 9 as hydrochloric acid. The hydrochloric acid recovered in the absorption step 9 is further distilled in the distillation step 10 and recovered as hydrochloric acid with less impurities. Then, in the purification step 11, chlorine, iron and the like in the hydrochloric acid are removed. In this purification step 11, an adsorbent such as activated carbon is used. Further, since a small amount of hydrogen chloride is contained in the exhaust gas discharged from the absorption step 9, this hydrogen chloride is neutralized and removed by caustic soda or the like in the detoxification step 12.

FIG. 2 shows a processing flow of another embodiment of the present invention, in which the chlorine-containing resin to be dechlorinated is a solid chlorine-containing resin. In FIG.
Numeral 16 is a crushing step for crushing the pyrolysis resin residue after dechlorination, and the other constitutions do not include the drying step 2, the volume reducing step 3, the washing step 13 and the drying step 14 in FIG. Except for this, it is the same as FIG. In the processing flow of FIG. 2, after the solid chlorine-containing resin is crushed to a size that can be supplied to the dechlorination step 4 in the crushing step 1, the solid chlorine-containing resin is dechlorinated in the dechlorination step 4 as in the case of FIG. 1. . Normal,
The pyrolysis resin residue containing the solid heat medium after the dechlorination treatment is a foamed granular material, and is subjected to the crushing treatment in the crushing step 16 to facilitate separation from the solid heat medium, and then solidified in the separation step 6. The heating medium is separated from the pyrolysis resin residue. As in the processing flow of FIG. 1, the separation step 6 may be omitted, or only a part of the solid heat medium may be separated.
Since the subsequent steps are the same as those in FIG. 1,
The same reference numerals are given and detailed description is omitted. Also, the processing steps of the gas generated from the dechlorination step 4 are the same as those in FIG. 1, and therefore the same reference numerals are given and the detailed description is omitted.

The processing flow for treating the film-like chlorine-containing resin and the solid-state chlorine-containing resin has been described above. However, in the method of the present invention, the treatment is performed without distinguishing the film-like chlorine-containing resin from the solid chlorine-containing resin. For example, as shown in FIG. 3, before the dechlorination step 4, the film-form chlorine-containing resin and the solid-form chlorine-containing resin are separately treated in the same manner as in the processing flows of FIGS. 1 and 2, respectively. And
From the dechlorination step 4, the two can be treated without distinguishing each other. In addition, the crushing step 16 may be performed as necessary depending on the properties of the pyrolysis resin residue. Note that the steps of the processing flow shown in FIG. 3 are the same as those in FIGS. 1 and 2, and thus the same reference numerals are given and the detailed description is omitted.

FIG. 4 shows an embodiment in which the present invention is applied to a chlorine-containing resin treatment facility. Reference numeral 17 denotes a chlorine-containing resin crusher provided on the equipment entrance side, and reference numeral 18 denotes this crusher. A magnetic separator (a device for magnetically separating the chlorine-containing resin conveyed on the conveyor) for removing metals from the chlorine-containing resin crushed in 17, and 19 is magnetically separated by the magnetic separator 18. A transfer means for transferring the film-form chlorine-containing resin, 21 is a dryer for drying the film-form chlorine-containing resin transferred by the transfer means 19, and 22 is a dryer for drying the film-form chlorine-containing resin. A volume reduction machine for volume reduction processing, 20 is the magnetic separator 18
Transfer means for transferring the solid chlorine-containing resin magnetically separated in the above, 23 is a storage tank for the chlorine-containing resin, 24 is a storage tank for the solid heat medium used in the dechlorination treatment apparatus, and 25 is the storage tank 23 Transfer means for transferring the chlorine-containing resin and the solid heat medium cut out from the, 24 to the dechlorination treatment apparatus, 2
6 is a rotary kiln type dechlorination apparatus, 27 is a combustion furnace for burning the generated gas containing chlorine and hydrogen generated by the dechlorination apparatus 26, and 28 is by blowing a high temperature gas after the combustion processing into the aqueous solution. A cooling facility for quenching, 29 is an absorption tower for absorbing hydrogen chloride (hydrochloric acid vapor) in the gas discharged from the cooling facility 28, and 30 is a coarse tower for storing the crude hydrochloric acid recovered in the absorption tower 29. A hydrochloric acid tank, 31 is a neutralization tower for neutralizing the hydrogen chloride-containing gas discharged from the absorption tower 29, 32 is a stripping tower for distilling the hydrochloric acid recovered in the crude hydrochloric acid tank 30,
33 is a recovered hydrochloric acid tank, 34 is an impurity removing device for removing impurities from the recovered hydrochloric acid, 35 is a means for transferring the pyrolysis resin residue containing the solid heat medium discharged from the dechlorination treatment device 26, 36 is A vibrating sieve for separating the solid heat medium from the pyrolysis resin residue containing the solid heat medium, 37 means for transferring the pyrolysis resin residue discharged from the vibrating screen 36, 38 a pyrolysis resin residue containing the solid heat medium A crusher 39 for crushing the gas, 39 is a hot air generator for generating a heating gas to be supplied to the desalination device 26, and 40 is a heating gas and a dechlorinated gas discharged from the dechlorination device 26. Carrier gas (such as nitrogen) to be supplied to the processing device 26
Is a heat exchanger for heating the carrier gas by exchanging heat with the carrier gas.

In the other drawings, reference numeral 41 denotes a storage hopper for storing the pyrolysis resin residue after the dechlorination treatment, and reference numeral 42 denotes a heated hydrochloric acid aqueous solution discharged from the bottom of the stripping tower 32 and introduced into the absorption tower 29. A cooling device for cooling; 43, a heating device for the hydrochloric acid aqueous solution discharged from the bottom of the stripping tower 32; 44, a hydrochloric acid cooling device; 45, 46, 47 blowers;
48, 49 and 50 are pumps.

Next, a method for treating a chlorine-containing resin in the above facility will be described. Normally, the film-form chlorine-containing resin and the solid-form chlorine-containing resin are separately carried into the facility and separately treated. The film-like chlorine-containing resin carried into the facility is crushed by a crusher 17, and then iron and main metals and metals are removed via a magnetic separator 18, and then sent to a dryer 21 by a transfer means 19. And dried. Next, after being subjected to a volume reduction treatment (for example, a resin is softened or melted or semi-melted by friction heat by stirring or extrusion or external heating, and then solidified) by the volume reducer 22, the resin is stored in the storage tank 23. Will be stored. On the other hand, the solid chlorine-containing resin carried into the facility is crushed by the crusher 17, then transferred as it is by the transfer means 20, and stored in the storage tank 23.

The chlorine-containing resin (film-like chlorine-containing resin or solid chlorine-containing resin) cut out from the storage tank 23 is transferred by the transfer means 25 together with the solid heat medium (for example, coke) cut out from the storage tank 24. It is supplied to a rotary kiln type dechlorination apparatus 26. A heating gas (a heating gas for indirectly heating the chlorine-containing resin in the device) is supplied to the dechlorination device 26 from a hot air generating furnace 39, and the gas (nitrogen) heated by the heat exchanger 40 is supplied to the dechlorination device 26. ) Is supplied as a carrier gas of hydrogen chloride gas generated in the apparatus. In the dechlorination device 26, the chlorine content contained in the resin is dissociated as chlorine hydrogen gas by heating the chlorine-containing resin together with the solid heat medium. The gas containing chlorine hydrogen generated from the dechlorination device 26 is introduced into the combustion furnace 27, and the organic components contained in the generated gas are almost completely burned off. This combustion furnace 2
The hot gas discharged from 7 is introduced into the cooling equipment 28,
Here, it is rapidly cooled by being blown into an aqueous solution.
In the cooling facility 28, the high-temperature gas is rapidly cooled, and the hydrogen chloride in the gas is absorbed by the aqueous solution to become a part of the hydrochloric acid aqueous solution in the cooling facility.

The gas quenched in the cooling equipment 28 is discharged from the cooling equipment together with hydrogen chloride (hydrochloric acid vapor),
It is led to 9. Soft water or treated water is supplied to the absorption tower 29, and hydrogen chloride in the gas is recovered as hydrochloric acid in the absorption tower 29 and stored in a crude hydrochloric acid tank 30. Exhaust gas discharged from the top of the absorption tower 29 is introduced into the neutralization tower 31 and neutralized with caustic soda. The crude hydrochloric acid stored in the crude hydrochloric acid tank 30
And distilled into hydrochloric acid. The hydrochloric acid recovered from the top of the stripping tower 32 is stored in a recovered hydrochloric acid tank 33, after which impurities are removed by an impurity removing device 34 and recovered as product hydrochloric acid.

On the other hand, the pyrolysis resin residue after the dechlorination treatment in the dechlorination treatment device 26 is discharged from the dechlorination treatment device 26 together with the solid heat medium, and sent to the next step by an appropriate transfer means 35. . That is, when the processing target is a film-like chlorine-containing resin, the pyrolysis resin residue including the solid heat medium is discharged out of the system via the transfer means 37 and the like after the solid heat medium is separated by the vibrating sieve 36. . Further, the separated solid heat medium is sent to the storage tank 24 by an appropriate transfer means, and from the storage tank 24 via the transfer means 25, the dechlorination treatment device 2
6 is used cyclically. When the processing target is a solid chlorine-containing resin, the pyrolysis resin residue containing the solid heat medium is crushed by a crusher 38, and then separated by a vibrating sieve 36 in the same manner as above. Then, the separated pyrolysis resin residue and the solid heat medium are respectively treated in the same manner as described above.

[0029]

EXAMPLE Processing of chlorine-containing resin using the equipment shown in FIG.
Was done. Files such as collected agricultural vinyl sheets
Lum-like chlorine-containing resin (water: 25 mass%, chlorine: 22.
5 mass%, inorganic matter: 15 mass%) at 1,260 kg / hr
To the crusher 17 at a supply rate of
(Hereinafter referred to as “Rotary Kiln 26”)
Crushed to the appropriate dimensions. Thereafter, the dryer 21 and the volume reducer 22
Through a 30 mmφ volume-reduced material (water: 8.7 mass%,
Chlorine 37.8 mass% (dry basis), ash content: 3.2 mass%
(Dry basis)). This is temporarily stored in storage tank 23
750 kg / hr after storage, coke in storage tank 24
(Solid heating medium): Rotor with supply amount of 375 kg / hr
It was supplied to the leak kiln 26. In the rotary kiln 26
Is discharged from the rotary kiln 26 in the heat exchanger 40.
Nitrogen heated to 200 ° C by the emitted heating gas
With 300 Nm as carrier gas³/ Hr supply amount
Supplied. In addition, the temperature inside the rotary kiln 26 becomes 325 ° C.
430 ° C. generated by the hot air generator 39
17000Nm for heating gas ³/ H with rotary feed rate
It was supplied to the kiln 26.

From the rotary kiln 26, 622 kg /
The hr-dechlorinated product (pyrolysis resin residue) and coke were discharged, and this was separated into dechlorinated product and coke by the vibrating sieve 36, and the coke was returned to the storage tank 24 and used for circulation. On the other hand, the dechlorinated product is sent to the storage hopper 41 and 262 kg /
hr of dechlorinated product was recovered. The gas generated from the rotary kiln 26 was supplied to a combustion furnace 27, and the organic components contained in the gas were completely burned at 1350 ° C. with fuel gas and air. Table 1 shows the composition and temperature of the gas generated from the rotary kiln 26 and the gas after the combustion treatment. Combustion furnace 27
The high-temperature combustion gas discharged from the furnace was sent to the cooling equipment 28 to rapidly cool the gas. The gas containing hydrochloric acid vapor discharged from the cooling equipment 28 is sent to the absorption tower 29 to collect the crude hydrochloric acid, and the collected crude hydrochloric acid is treated through the stripping tower 32 and the impurity removing device 34 to obtain 695 kg / hr of 35%. % Hydrochloric acid aqueous solution was recovered.

[0031]

[Table 1]

[0032]

According to the present invention described above, a chlorine-containing resin is dechlorinated, and high-purity, high-concentration hydrochloric acid can be stably recovered from the generated gas.

[Brief description of the drawings]

FIG. 1 is a processing flowchart showing an embodiment of the present invention.

FIG. 2 is a processing flowchart showing another embodiment of the present invention.

FIG. 3 is a processing flowchart showing another embodiment of the present invention.

FIG. 4 is an explanatory view showing one embodiment in which the present invention is applied to a chlorine-containing resin treatment facility.

[Explanation of symbols]

1 ... crushing step, 2 ... drying step, 3 ... volume reduction processing step, 4
... dechlorination step, 5 ... cooling step, 6 ... separation step, 7 ... combustion step, 8 ... rapid cooling step, 9 ... absorption step, 10 ... distillation step,
11: purification step, 12: detoxification step, 13: washing step, 1
4 ... Drying process, 15 ... Crushing process, 16 ... Crushing process, 17
... Crusher, 18 ... Magnetic separator, 19 ... Transfer means, 20 ... Transfer means, 21 ... Dryer, 22 ... Volume reducer, 23 ... Storage tank, 2
4 ... storage tank, 25 ... transfer means, 26 ... dechlorination treatment device,
27: combustion furnace, 28: cooling equipment, 29: absorption tower, 30 ...
Crude hydrochloric acid tank, 31 neutralization tower, 32 diffusion tower, 33 recovered hydrochloric acid tank, 34 impurity removal device, 35 transfer means, 36 vibration vibrator, 37 transfer means, 38 crusher, 3
9 hot air generator, 40 heat exchanger, 41 storage hopper, 42 cooling device, 43 heating device, 44 hydrochloric acid cooling device, 45, 46, 47 ... blower, 48, 49, 50 ...
pump

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C08J 11/12 B01D 53/34 134B F23G 5/027 ZAB 5/033 (72) Inventor Teishi Iemoto Tokyo 1-1-2 Marunouchi, Chiyoda-ku Nihon Kokan Co., Ltd. (72) Inventor Shinya Sekine 1-1-2 Marunouchi, Chiyoda-ku, Tokyo Nihon Kokan Co., Ltd. F-term (reference) 3K061 AA07 AB02 AC13 BA01 CA08 FA21 3K065 AA07 AB02 AC13 BA01 CA01 CA02 CA10 CA13 4D002 AA19 BA02 BA05 BA13 CA01 CA06 DA35 EA02 FA01 GA03 GB03 HA01 4F301 AA17 BA12 BA21 BF02 BF12 BF27 CA09 CA24 CA36 CA42 CA68 CA72 CA73

Claims (5)

[Claims] 1. A step (A) of pretreating a chlorine-containing resin for a dechlorination treatment; and heating the chlorine-containing resin that has passed through the step (A) to cause thermal decomposition so that chlorine content in the resin is converted to chloride. A step (B) of desorbing as a hydrogen gas; and a step (C) of burning off a gas containing hydrogen chloride discharged from the step (B) to remove organic components contained in the gas.
And a step (D) of recovering hydrogen chloride in the gas that has passed through the step (C) as hydrochloric acid. 2. A step of rapidly cooling the high-temperature gas containing hydrogen chloride which has passed through the step (B) between the step (B) and the step (C).
The method for recovering hydrochloric acid from a chlorine-containing resin according to claim 1, wherein (E) is provided. 3. The chlorine-containing resin to be dechlorinated comprises a film-like chlorine-containing resin, and the step (A) comprises a step (a1) of crushing the film-like chlorine-containing resin, and the step (a1). 3. The method according to claim 1, further comprising: a step (a2) of drying the film-like chlorine-containing resin; and a step (a3) of reducing the volume of the film-like chlorine-containing resin after the step (a2). A method for recovering hydrochloric acid from a chlorine-containing resin as described in the above. 4. The method according to claim 1, wherein the chlorine-containing resin to be dechlorinated comprises a solid chlorine-containing resin, and the step (A) comprises a step (a) of crushing the solid chlorine-containing resin. Item 3. The method for recovering hydrochloric acid from a chlorine-containing resin according to Item 1 or 2. 5. The chlorine-containing resin to be dechlorinated comprises a film-like chlorine-containing resin and a solid chlorine-containing resin, and the step (A) comprises a step of crushing the film-like chlorine-containing resin (a1); A step (a2) of drying the film-like chlorine-containing resin after the step (a1); a step (a3) of reducing the volume of the film-like chlorine-containing resin after the step (a2); A crushing step (a4), wherein the chlorine-containing resin that has passed through the step (a3) and the chlorine-containing resin that has passed through the step (a4) are sent to the step (B) without distinguishing the two. The method for recovering hydrochloric acid from a chlorine-containing resin according to claim 1 or 2.