JPH10263504A - Method for 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 is solidified and is reused as fuel, the problem of treating chlorine base gas generated due to chorine 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 and a dechlorinating agent of alkali hydroxide are subjected to heat treatment in plural temperature stages. The plural temperature adages are temperatures lower than that at which chlorine base gas is separated and temperatures at which chlorine base gas is separated and reacted with the incorporated dechlorinating agent to form harmless chloride. In this way, safe solidified material from which chlorine base gas is not generated even when it is burned later is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for heating and treating solidified products such as wastes, and a solidified product formed by this method. The present invention relates to a method of performing a chemical conversion treatment and a solidified product.

[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] In the present invention, the treatment method for solidifying the treated material is to mix the treated material with a dechlorinating agent for an alkali metal hydroxide that reacts with a chlorine-based gas and heat-treat the mixture in a plurality of temperature ranges to produce The obtained product is subjected to pressure molding and solidified into a pellet.

At this time, the temperature at the time of the heat treatment is not more than the temperature (200 to 300 ° C.) at which the precipitation of the chlorine-based gas starts, and then the chlorine-based gas is precipitated at 300 to 500 ° C. Reacts to produce harmless chloride.

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 appropriately used. .

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

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

When a dechlorinating agent is added to the treated product under the above-mentioned conditions and heat treatment is performed, for example, sodium hydroxide (N
When aOH) is added, it reacts with hydrogen chloride (HCl) to give:

(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 chlorine-hydrogen gas, which is a cause of dioxin, and can achieve detoxification of exhaust gas and residues.

On the other hand, no harmful chlorine-based 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 treated 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

[0025]

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.

Reference 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,
The heating (dry distillation) treatment is performed by the heating means 4. (The heat treatment may be performed in a granulator.) The heat treatment is performed in at least two or more stages having different heating temperature ranges. The temperature range of the latter stage is made higher than that of the former stage.

As shown in FIG.
A heat treatment (dry distillation) is performed at a temperature of 00 ° C. or less, preferably 150 ° C. to 250 ° C., with the outside air shut off for 10 minutes. Next, a heat treatment is performed at 300 to 600 ° C. (preferably 400 to 500 ° C.), which is higher than that in the previous step, to precipitate a chlorine-based gas from the processed product, and to react with the added dechlorinating agent to produce harmless chloride. Let it.

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 mixed with the processed material in a softened state, and are molded, so that the plastics serve as an adhesive (binder) between the processed materials. Acting, the pallets produced maintain a stable solid form.

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 the compression molding in this manner, the volume ratio of the pellet is reduced as follows.

[0034]

[Table 1]

Using the processed material solidified by the above-described processing method as a fuel, the chlorine component contained in the processed material to be burned is determined to be harmless by the following experiment. Chloride was generated, and it was found that the exhaust gas and the residue did not contain harmful chlorine-based gas components.

In the experiment, a low-oxygen atmosphere was created in a closed vessel having an exhaust pipe and an opening / closing door.
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 with 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.

[0040]

[Table 2]

In the experiment, first, a preliminary experiment was conducted 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 is a sample obtained by adding 20 g of slaked lime powder as a conventional dechlorinating agent to 4 g of the same treated product.
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 processed material was referred to as Example 1, and the sample was subjected to dechlorination. 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, a preliminary test was conducted using only polyvinylidene chloride containing a large amount of a chlorine component. As a result, 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 between 600 ° C. and 1000 ° C.

When sodium hydroxide reacts with chlorine-based gas, detoxification of gas and 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.

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

On the other hand, NaCl produced by the reaction is a harmless chloride, and this NaCl can be effectively removed by washing with a solution such as water.

FIG. 3 is an explanatory view for 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 to remove it from the treated ash. Next, this is dehydrated and dried to be solidified. After cleaning, valuable carbonized material remains.

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

From the above, the following substances showing the same reaction as described 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 and 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. If this is formed into pellets by a granulator, it can be effectively used as fuel.

Further, 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 as fuel or other effectively.

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.

[0063]

As described above, according to the present invention, a treated product is mixed with a dechlorinating agent, first heat-treated at a low temperature below the temperature at which chlorine-based gas is precipitated, and then heat-treated at a high temperature. Since the solidified material (pellet) is formed by pressurizing, (1) a safe pellet free of generation of chlorine-based gas (hydrogen chloride, chlorine gas) when burning the solidified material is obtained.

(2) Even in the process of producing pellets, harmful chlorine-based gas in the exhaust gas is generated because harmful chlorine-based gas in the generated gas reacts with the dechlorinating agent to form harmless chloride. Can be effectively removed, and the generation of Diokin is prevented even if the exhaust gas is directly discharged into the atmosphere.

(3) 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 an explanatory diagram of a processing method 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 (13)

[Claims] 1. A process wherein a treated product and a dechlorinating agent for an alkali metal hydroxide that reacts with a chlorine-based gas are mixed and heat-treated in a plurality of temperature ranges, and the produced product is solidified into pellets. A method for solidifying a treated product, characterized by the following. 2. The heat treatment temperature range is set higher in a temperature range in a latter stage than in a former stage, and the temperature range in a former stage is a temperature at which chlorine-based gas starts to be deposited, and the temperature is maintained for a predetermined time. Item 6. A method for solidifying a treated product according to Item 1. 3. The temperature range before the heat treatment is 200 ° C.
The method according to claim 1, wherein the temperature is set to 300 ° C. 4. 4. The heat treatment temperature range is set higher in the latter stage than in the former stage, and the latter temperature range is set to a temperature at which the deposited chlorine-based gas is fixed to the dechlorinating agent, and the temperature is maintained for a predetermined time. The method for solidifying a treated product according to claim 1, wherein: 5. The temperature range of the latter stage of the heat treatment is 300 ° C.
The method for solidifying a treated product according to claim 1 or 4, wherein the temperature is set to 500C. 6. The method according to claim 1, wherein the heat treatment is performed in a low oxygen atmosphere. 7. The solidification treatment of a treated product according to claim 1, wherein the dechlorinating agent is selected from a simple substance of an alkali metal hydroxide, a mixture of two or more simple substances, and a mixture of two or more simple substances. Method. 8. 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 method for solidifying a treated product according to claim 1, wherein: 9. The dechlorinating agent may be in the form of a block, a plate, a porous,
The solidification treatment method for a treated product according to any one of claims 1, 7, and 8, wherein the treatment product is formed in the form of a powder, a solution, or a suspension. 10. The method according to claim 1, wherein the amount of the dechlorinating agent is 5 to 30% by weight of the processed material.
The solidification treatment method for a treated product according to any one of 7, 8, and 9. 11. The method according to claim 1, wherein the dechlorinating agent is added in an amount of 0.5 to 1.5 mol based on the amount of the generated chlorine component. 3. A method for solidifying a treated product according to item 1. 12. 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 . 13. A mixture of a treated product and a dechlorinating agent for an alkali metal hydroxide which reacts with a chlorine-based gas, heat-treated in a plurality of temperature ranges, and press-formed the resulting product into pellets. A solidified processed product characterized by being solidified.