JPH10263503A - Method of solidifying material to be treated and solidified material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To contrive solving a problem arising when material to be treated such as municipal refuse containing plastics is solidified and is reused as fuel, the problem of treating chlorine base gas generated due to chlorine components contained in the material to be treated which problem is that when chlorine base gas discharged from a heating process is released in the air as it is, it becomes determinants of the production of dioxin. SOLUTION: Material to be treated containing plastics and a dechlorinating agent consisting of alkali metal hydroxide are put in a mixer 2 to mix them, and the mixture is subjected to heat treatment by a heating means 4 at temperature lower than that at which chlorine base gas is generated and the product is heated and formed into pellets by a granulator 5. When the pellets are burned as fuel, chorine base gas is reacted with the dechlorinating agent in which is contained to realize making of the gas harmless and from harmless chloride. Therefore, waste gas can be released in the air as it is.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of heating and solidifying a treated material such as waste, and a solidified material formed by this method. And a method of solidifying the mixture by mixing the same.

[0002]

2. Description of the Related Art The amount of processed waste such as municipal garbage increases year by year, and its disposal has become a problem. In general, municipal garbage is mainly discharged from general households or offices as flammable waste. Recently, it has been considered that this flammable treated material is not simply incinerated, but is effectively used as a resource, and the treated material is once solidified and reused as fuel. However, some of the processed materials contain a large amount of chlorine components in recent years, such as a wide variety of chemical substances, for example, plastics containing a large amount of vinyl chloride resin and chlorine bleach for office paper. Due to the inclusion of substances, simply solidifying will generate harmful chlorine-based gas when used and burned as fuel, and if released directly into the atmosphere, it will cause air pollution and have undesirable environmental consequences . Therefore, there is a problem in reusing as a high-efficiency and clean energy resource, and development of a technology corresponding to this problem has become an important issue.

[0003]

A problem that arises when heat-treating a treated product is the treatment of chlorine components contained in the treated product, and the chlorine-based gas (hydrogen chloride, chlorine chloride) gasified in the incineration process. Gas) is subjected to an adsorption treatment with a filter or the like so that chlorine-based gas is not discharged into the atmosphere.

[0004] On the other hand, chlorine components that have not been gasified during the heating process are combined with the treated ash, resulting in treated ash containing a high concentration of chlorine components.

[0005] If the treated ash contains a chlorine component as described above, it is difficult to reuse the treated ash as a fuel resource, and the ash is treated only by burying it in the ground.

Therefore, when reusing the treated ash,
Processed materials are separated in advance, only processed materials that generate less chlorine-based gas are selected and incinerated, and the processed ash (residue) is solidified as fuel or in a block or the like and reused.

[0007] However, since the separation of the treated material is inefficient and the resource recovery rate is low, it is desired to establish a technique for effectively removing the chlorine component.

[0008] Further, it is also practiced to solidify the processed material (garbage) and use it as a fuel. However, at present, the flammable processed material is simply compressed and solidified. Can be achieved, but when used as a fuel, harmful chlorine-based gas is generated in the same manner as described above, and countermeasures are required.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and its object is to produce a chlorine-based gas (hydrogen chloride,
A solidification treatment method for a treated material that does not generate chlorine gas);
It is to provide the solidified product.

[0010]

As a result of numerous experimental investigations, the inventors of the present application have found that a proper amount of a chlorine component and an alkali metal hydroxide contained in a treated material is mixed into the treated material as a dechlorinating agent, When the heat treatment is performed at a temperature of, the chlorine component is decomposed at a predetermined temperature to generate harmful chlorine-based gas, and the harmful chlorine-based gas reacts with the dechlorinating agent to generate harmless chloride, and the gas is removed. It was also found that no harmful chlorine-based gas components remained in the residue.

Attention is also paid to the fact that a dechlorinating agent is added during the heat treatment to perform a treatment aimed at the dechlorination effect. In addition, we focused on manufacturing by mixing a dechlorinating agent.

[0012] The inventors first searched for a substance having a dechlorination effect, and investigated the effect of mixing the substance into pellets and burning it.

The present invention has been made based on these experimental investigations, in which a treated product is solidified by mixing a dechlorinating agent,
When this was incinerated as a fuel, a solidified fuel that did not generate harmful chlorine-based gas could be obtained.

[0014] When the processed material is solidified by utilizing the heat softening property of the plastic contained in the processed material,
This plastic is used as a binder to form a solidified fuel having a high density and a stable shape.

In the present invention, the treatment method for solidifying the treated material comprises treating a treated material of plastics containing all or a part of plastic with a dechlorinating agent for an alkali metal hydroxide which reacts with chlorine-based gas. It is characterized in that it is mixed, heat-treated, and the resulting product is pressure-formed and solidified.

The temperature during the heat treatment at this time is not higher than the temperature at which the chlorine-based gas starts to precipitate (200 to 300 ° C.) or the temperature at which the melting temperature of the plastic starts (100 to 15).
0 ° C).

Then, the product is compression-molded by a granulator to form a solidified product (pellet). Alternatively, a dechlorinating agent is further added to the product to form pellets.

As the dechlorinating agent used in the present invention, (1) an alkali metal hydroxide selected from a simple substance, two or more simple substances, and a mixture of two or more simple substances.

(2) A simple substance selected from sodium hydroxide, potassium hydroxide, lithium hydroxide, rubidium hydroxide, and cesium hydroxide, a mixture of two or more simple substances, and a mixture of two or more simple substances are used.

When the dechlorinating agent is used, it is added in any state of a lump, a porous form, a powdery (powder, granular) aqueous solution, and a suspension.

The amount of addition is equivalent to the processed material to be treated or equivalent to 5 or
To 30% by weight, or 0.5 to the generated chlorine-based gas
Add ~ 1.5 mol.

The pressing force for producing a solid material is 10 to 1000 kg / kg for the reason that solidification is difficult if the pressing force is small, and the equipment becomes large if the pressing force is large.
cm ² is preferred.

Under the above-mentioned conditions, a dechlorinating agent is added to the treated product and heat-treated, and the produced product is solidified and used as a fuel.
aOH), the generated hydrogen chloride (HC
l) reacts with:

(NaOH) + (HCl) → (NaCl) + (H ₂ O) As described above, hydrogen chloride reacts with sodium hydroxide to form sodium chloride (NaCl), which is a part of the residue, and water (H). ₂ O), and does not generate hydrogen chloride gas which contributes to the cause of dioxin, and can make the exhaust gas and the residue harmless.

On the other hand, no harmful chlorine gas components are contained in the residue, and NaCl can be easily dissolved and removed with a solution such as water, so that the carbonized material remaining after washing can be effectively used as fuel or the like.

Since the treatment liquid after cleaning contains almost no harmful chlorine-based gas components, it can be discharged to rivers and oceans as it is or after removing other harmful substances other than chlorine components. Becomes

[0027]

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

FIG. 1 is a conceptual diagram of an embodiment of the present invention.
Denotes a processing material supply unit, 2 denotes a mixer, and 3 denotes a dechlorinating agent supply unit. Reference numeral 4 denotes a heating means for heating the processed material in the mixer 2.
The heating means 4 includes gas heating, electric heating or combustion heating,
Any heating means such as microwave heating and induction heating may be used.

Numeral 5 denotes a granulator having a heating means 6 on the outside and a press means comprising a pressure roller and the like inside.
Reference numeral 7 denotes a solidified product (pellet) formed by the granulator 5.

The procedure for manufacturing the pellets is as follows. First, the processed material is charged into the processed material supply unit 1, the dechlorinating agent is stored in the dechlorinating agent supply unit 3, and these are supplied to the mixer 2 at a predetermined ratio. I do. In the mixing machine 2, while mixing the processed material and the dechlorinating agent,
200 ° C. or less, preferably 100 ° C.
A heat treatment (dry distillation) is performed for 10 minutes at a temperature of 150 ° C. with the outside air shut off.

Next, the opening / closing door 2b of the mixer 2 is opened, the mixture is supplied to the granulator 5, and the mixture is compression-molded by press means while heating the mixture under the same temperature conditions as described above. Then, a pellet 7 is formed. The crushing function may be added to the mixer 2.

In the above process, if plastics are mixed in the processed material, the plastics are supplied in a softened state (if they are not mixed or the amount is small, they are separately supplied from the processed material supply unit 1). As it is mixed with the material and molded, it serves as an adhesive (binder) between the processed materials, and the produced pellets maintain a stable solid shape.

The pressing means includes, for example, a feed rotary roller for feeding out the mixture and a squeezing rotary roller (which may be a heating roller) for compression molding. / C
to adjust to the m ^2. If the pressure is small, solidification is difficult, and if it is too large, the equipment becomes large.

By performing compression molding in this manner, the volume ratio of the pellets is reduced as follows.

[0035]

[Table 1]

FIG. 2 shows another embodiment of the present invention, in which a screw feeder 10 is provided between the mixer 2 and the granulator 5. The screw feeder 10 includes a heating unit 11
And provided to further promote the mixing of the treated product and the dechlorinating agent.

Since the screw feeder 10 is also heated in a dry distillation state, it is configured to be shielded from outside air. Accordingly, the inlet side and each have a door 10d ₁ and 10d ₂ on the outlet side, rotary driven screw 10b is provided in the cylindrical member 10a, transported while mixing the treated product and the dechlorinated agent.

The heating may be performed in either the mixer 2 or the screw feeder 10, or may be performed in both.

Several processed materials (pellets) solidified by the above-described processing method are placed in a closed vessel equipped with an exhaust pipe, heated in an electric furnace, the generated gas is extracted, and the hydrogen chloride concentration (p
pm), no hydrogen chloride was detected.

Further, as a result of taking out the treated ash and detecting a chlorine component, only harmless chloride (sodium chloride) was detected.

From this, it was found that the harmful chlorine-based gas that would be generated forms harmless chlorides, and that the exhaust gas and the residue do not contain harmful chlorine-based gas components.

The following experimental investigation revealed that the alkali metal hydroxide reacts with the harmful chlorine-based gas in the gas to form harmless chloride.

In the experiment, a low oxygen atmosphere was created in a closed vessel having an exhaust pipe and an opening and closing door, a sample was placed in this closed vessel, heated in an electric furnace, and heated from 250 ° C to 600 ° C.
Hold at each temperature for 5 minutes at intervals of 0 ° C., and measure the concentration (ppm) of hydrogen chloride gas (HCl) at the time of temperature rise and at the time of keep.

The gas concentration was measured using a detector tube specified in JIS-K0804.

Table 1 shows the measurement results. In Table 1, the concentration of hydrogen chloride gas is a measured value in ten experiments, Examples 1 and 2 show the highest values, and Comparative Examples 1 to 4 show the lowest values.

Note that "ND" represents "not detected" and 1
It shows that none was detected in 0 experiments.

[0047]

[Table 2]

In the experiment, first, a preliminary experiment was performed using only polyvinylidene chloride containing a large amount of a chlorine component as a treated material. Comparative Example 1 and Comparative Example 2 in Table 1 are each 1
g and 4 g were used as samples for preliminary experiments in which no dechlorinating agent was added.

Comparative Example 3 was a sample obtained by adding 20 g of slaked lime powder as a conventional dechlorinating agent to 4 g of the same treated material.
Was a sample obtained by adding calcium carbonate as a dechlorinating agent to 4 g of the same treated product.

Next, as an example of the dechlorination treatment according to the present invention, a sample in which 20 g of pulverized sodium hydroxide was added as a dechlorinating agent to 4 g of polyvinylidene chloride as a treated material was designated as Example 1, and the sample was treated with the same treated material. A sample to which 20 g of ground potassium hydroxide was added as a chlorine agent was used as Example 2. Powder having an average particle size of 100 μm was used as a dechlorinating agent.

The following is considered from the experimental results shown in Table 1.

First, as a result of a preliminary test using only polyvinylidene chloride containing a large amount of a chlorine component, as shown in Comparative Examples 1 and 2, a large amount of hydrogen chloride was generated by the heat treatment.

Next, Comparative Examples 3 and 4, in which slaked lime and calcium carbonate, which are conventional dechlorinating agents, were added, Comparative Examples 1 and 2 were used.
However, although the generation of hydrogen chloride is considerably suppressed, it is still not sufficient.

On the other hand, in Examples 1 and 2 in which sodium hydroxide and potassium hydroxide as alkali metal hydroxides were added as dechlorinating agents to the above treated products, the temperatures in Example 1 were 350 ° C. and 450 ° C. Although slight generation of hydrogen chloride gas was observed when the temperature was raised at 5 ° C. and when the temperature in Example 2 was kept at 450 ° C. for 5 minutes, hydrogen chloride gas was not detected over the entire temperature range, and it was very good. The result was obtained. Therefore, according to this example, very good results were obtained as compared with Comparative Examples 1 to 4.

The same effect was obtained at a temperature of 600 ° C. or more and 1000 ° C.

When sodium hydroxide reacts with chlorine-based gas, detoxification of the gas and the residue can be realized because harmful chloride-based gas is replaced with harmless chloride as follows.

Here, when sodium hydroxide (NaOH) is used as a dechlorinating agent and added to the processed product, the reaction is as follows:
As described above, sodium hydroxide is converted to hydrogen chloride (HCl).
The following reaction formula proceeds between and.

(NaOH) + (HCl) → (NaCl) + (H ₂ O) Thus, sodium hydroxide reacts with hydrogen chloride to produce harmless sodium chloride and water.

The reaction formula using potassium hydroxide (KOH) is as follows: (KOH) + (HCl) → (KCl) + (H ₂ O) Potassium hydroxide reacts with hydrogen chloride and is harmless potassium chloride And become water.

When the obtained residue was analyzed, no harmful chlorine-based gas was detected, and harmless chlorides sodium chloride (NaCl) and potassium chloride (KCl) were detected. Further, the residue was washed with water while stirring for 10 minutes, so that sodium chloride and potassium chloride were both dissolved in water, and a carbide remained, but no chlorine-based gas component was detected in the carbide.

Therefore, if an alkali metal hydroxide which reacts with chlorine components to form harmless chlorides in the dechlorinating agent is present, it becomes a part of the residue as sodium chloride or potassium chloride, which is one of the causes of the generation of dioxin. Hydrogen chloride, which is one of the above, is not generated, and it is possible to make these residues and exhaust gas harmless. Similar results can be obtained by using other dechlorinating agents such as lithium hydroxide, rubidium hydroxide and cesium hydroxide.

From this, the following substances showing the same reaction as above can be used as the dechlorinating agent.

(1) An alkali metal hydroxide selected from a simple substance, two or more simple substances, and a mixture of two or more simple substances.

(2) A simple substance selected from sodium hydroxide, potassium hydroxide, lithium hydroxide, rubidium hydroxide, cesium hydroxide, a mixture of two or more simple substances, and a mixture of two or more simple substances.

On the other hand, NaCl and KCl are produced by the reaction, and the produced NaCl and KCl are harmless chlorides, which can be effectively removed by washing treatment with a solution such as water, and can be reused after washing. The remaining carbonized material remains.

FIG. 3 is an explanatory view of washing the treated ash. The treated ash is put into a water tank, and stirred for a predetermined time (about 30 minutes) to dissolve sodium chloride (NaCl) in water and remove it from the treated ash. Next, this is dehydrated and dried to be solidified. After cleaning, valuable carbonized material remains.

Therefore, depending on the characteristics of the residue, the residue can be separated into various substances by a separation means or the like, and the separated substance can be dried and solidified to be used effectively as fuel or other materials.

Since the treatment liquid after washing contains almost no harmful substances, it can be discharged to rivers or oceans as it is.

The residual chlorine component in the residue was measured by ion chromatography.
What was not less than 00 ppm was not confirmed in the present invention,
Harmless chloride (NaCl) was identified.

[0070]

As described above, according to the present invention, a treated product containing plastics is mixed with a dechlorinating agent for an alkali metal hydroxide, and is first subjected to a heat treatment at a low temperature lower than a temperature at which a chlorine-based gas is precipitated. This is pressurized to form a solidified material (pellet). (1) When the solidified material is burned, no chlorine-based gas is generated, and the plastics are softened and the binder of the mixture is formed. Pellets with a stable shape that is easy to handle
That is, pellets suitable for carrying or transporting are obtained.

(2) Even if the pellets are burned as fuel, the presence of the dechlorinating agent reacts with the chlorine-based gas in the generated gas to produce harmless chlorides. Since gas components can be effectively removed, generation of dioxins is prevented even if the gas components are released into the atmosphere as they are.

(3) Since plastics have a strong burning power, the burning power (thermal power) of the processed material is increased when the pellets are burned.

(4) A safe pellet free of generation of chlorine-based gas (hydrogen chloride, chlorine gas) when the solidified product is burned is obtained.

(5) For the above reasons, it can be effectively reused as a solidified fuel which is convenient to handle.

The following effects are obtained.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram of an embodiment of the present invention.

FIG. 2 is a conceptual diagram of another embodiment of the present invention.

FIG. 3 is an explanatory diagram of the processing of the processing ash.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Process supply part 2 ... Mixer 3 ... Dechlorinating agent supply part 4, 6 ... Heating means 5 ... Granulator 7 ... Pellets

Claims (11)

[Claims] 1. A mixed product containing a plastic and a dechlorinating agent for an alkali metal hydroxide which reacts with a chlorine-based gas, and heat-treated. A solidification treatment of a processed product, wherein the solidification is performed by using a binder as a binder. 2. The method according to claim 1, wherein the heat treatment temperature is equal to or lower than a temperature at which precipitation of chlorine-based gas starts. 3. The method according to claim 1, wherein the heat treatment is performed in a low oxygen atmosphere. 4. The method according to claim 1, wherein the heat treatment is dry distillation. 5. The heat treatment temperature is a temperature at which the plastics are softened at a temperature not higher than a temperature at which the plastics are melted,
5. The method according to claim 1, wherein the plastics contained in the processed material act as a binder. 6. The method according to claim 1, wherein the dechlorinating agent is selected from a simple substance of an alkali metal hydroxide, two or more simple substances, and a mixture of two or more simple substances. . 7. The dechlorinating agent is selected from a simple substance selected from sodium hydroxide, potassium hydroxide, lithium hydroxide, rubidium hydroxide, and cesium hydroxide, a mixture of two or more simple substances, and a mixture of two or more simple substances. The solidification treatment method for a treated product according to claim 1 or 2, wherein: 8. The dechlorinating agent may be in the form of a lump, a plate, a porous form,
The solidification treatment method for a treated product according to any one of claims 1, 6, and 7, wherein the treatment product is formed in any of a powder form, a solution, and a suspension. 9. The method according to claim 1, wherein the amount of the dechlorinating agent added is 5 to 30% by weight of the processed material.
The method for solidifying a treated product according to any one of claims 6, 7, and 8. 10. The pressure for pressure molding is 100 to 1000.
^{2. The} method for solidifying a treated product according to claim 1, wherein the solid content is set to kg / cm ² . 11. A processed material containing plastics,
A solidified material characterized by mixing a chlorine-based gas and a dechlorinating agent for an alkali metal hydroxide which reacts with a chlorine-based gas and heat-treating the mixture, and then press-molding the resulting product to solidify plastics as a binder.