JPH1043715A - Batch type dechlorinating treatment of waste - Google Patents

Abstract

PROBLEM TO BE SOLVED: To fix a chlorine component to a treated ash and to remove a chlorine component in a gas by filling a sealed tank with a waste and an additive which easily reacts with the chlorine component at specified temp., inserting the tank in a heating source, performing dry distillation while shielding the tank from external air. SOLUTION: When a waste such as city garbage is to be heat treated, the waste and an additive such as an alkali material and/or silicate which can reacts with the chlorine component at specified temp. are supplied to fill a tank 1. The tank is then shielded from external air by a sealing lid 2. Then the tank 2 is inserted into an induction heating coil 3 formed into a cylinder and heated to treat the waste by dry distillation. Then the tank 1 is taken out from the heating source and cooled. After the gas in the tank 1 is discharged, the residue (treated ash) is taken out. By dry distillation, the chlorine component is completely fixed to the ash, and the discharged gas is a combustible gas (Cn Hm ) containing no chlorine component. Therefore, the discharged gas is collected in a gas container 7 and used as a new fuel.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for heat-treating waste such as municipal garbage, and more particularly, to a method for batch-wise dechlorination of waste by using a closed tank.

[0002]

2. Description of the Related Art The amount of waste such as municipal waste is increasing year by year, and its disposal is a problem. Urban garbage is generally
It is emitted as waste from ordinary households and offices and is mainly flammable. This combustible waste contains a wide variety of chemical substances in recent years, such as plastics containing a large amount of vinyl chloride resin and substances containing a large amount of chlorine such as chlorine bleach for office paper. It is mixed. Techniques for effectively treating these wastes by heat treatment are being promoted in various industrial fields. However, when chemical substances are incinerated, harmful gases containing chlorine components are generated, causing problems such as environmental pollution and deterioration of incineration facilities due to chlorine, and it is difficult to obtain highly efficient and clean energy. The development of technology that responds to this is an important issue.

[0003]

There are a batch type, a quasi-continuous type, and a continuous type as a method of heat-treating waste, which is used depending on the amount of waste and the operation time (8 to 24 hours). I have.

There are various types of incinerators, such as a stoker type, a flow type, a shaft type, and a rotary type, which are used properly according to various conditions.

[0005] However, these facilities have a processing capacity of 20 t.
This is equipment with a standard of at least / 8h or more, and both systems are large equipment.

[0006] If the waste is heated, the volume can be reduced, but the problem is the treatment of chlorine components (chlorine and chlorine compounds) contained in the waste.

Generally, the chlorine component gasified in the heating process is subjected to an adsorption treatment with a filter or the like so that the chlorine component is not discharged into the atmosphere.

[0008] On the other hand, since chlorine components remain in the treated ash, it is necessary to devise a treatment of the treated ash.

As a treatment method for effectively extracting chlorine components in wastes, dry distillation treatment has been attracting attention. In this method, waste is steamed under a closed condition to remove a chlorine component from the waste.

[0010] However, it is possible to carry out dry distillation in a conventional heat treatment system and an incinerator, but there are problems in the following points.

(1) Conventional facilities are large, and there are merits of introducing facilities in an area where the amount of waste to be treated is considerable (20 t / day or more). The merits of introduction are small in local governments, general companies, and specific facilities.

That is, even if the system is introduced, the operation and the stop are repeated according to the amount of collected waste, and the running cost is increased. Therefore, the system is not actively introduced.

(2) It is difficult to effectively remove chlorine components from waste.

That is, since the isolation from the outside is not sufficient, the dry distillation is of the order of semi-dry distillation, and the extraction of the chlorine component from the waste is not sufficient.

Therefore, equipment such as a filter for removing chlorine components in the gas is required in the post-process, and maintenance of the equipment is also required, so that it cannot be easily installed.

In view of the above, the present invention provides a waste treatment system in which waste can be easily heat-treated with a small-scale treatment facility and the gas generated during the carbonization treatment contains no chlorine component. The aim is to provide a method.

[0017]

Means for Solving the Problems The present inventors have searched for a treatment method that does not discharge chlorine components in a simple heat treatment facility. It was found that this can be achieved by filling an additive that easily reacts with chlorine components, placing this tank in a heating source, and shutting off the outside air to perform dry distillation.

As a result of the experimental investigation, when an additive which easily reacts with the chlorine component at a predetermined temperature is mixed into the waste, the chlorine component is securely fixed to the treated ash, and the gas generated during the dry distillation contains the chlorine component. It was found that they were not contained, and that an alkali-based substance and / or silicate was suitable as an additive that easily reacted with a chlorine component at a predetermined temperature.

The present invention has been made on the basis of these findings, and is intended to fill a closed tank with waste and an additive which reacts with a chlorine component at a predetermined temperature, and put the whole tank into a heating source and heat it. Even if waste gas is subjected to dry distillation and the generated gas is released into the atmosphere as it is, no air pollution occurs.

In this way, by using a closed tank, for example, a tank having a size of a drum can, it is possible to configure an extremely small-scale waste treatment facility, and furthermore, to store the waste in the tank in a sealed primary storage. Therefore, it can be installed even in a facility (town, village, general company, specific facility) that generates less than 10 t / day of waste and can contribute to solving environmental issues.

An appropriate amount (5 to 3) of an alkaline substance and / or a silicate which easily reacts with a chlorine component is contained in the tank.
Ash (residue)
It is to be surely fixed.

The waste treatment step includes the steps of filling a waste tank with an additive that reacts with a chlorine component at a predetermined temperature in a closed tank, inserting the tank into a heating source,
Batch-type waste treatment is performed by heating the entire tank to dry distill the waste, removing the tank from the heating source, and cooling the tank to remove the treated ash.

[0023]

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

FIG. 1 is a conceptual diagram for explaining a waste disposal method according to the present invention. Reference numeral 1 denotes a tank, which is made of, for example, an iron-based material (preferably a magnetic material) and has an openable and closable lid 2.
Reference numerals 3 and 3 'denote heating coils which are formed in a cylindrical or rectangular tube shape and constitute a heating source by induction heating.
The tank 1 is inserted into the cylindrical shape. Then, the tank 1 is induction-heated by supplying AC power to the heating coil 3. Reference numeral 4 denotes an exhaust pipe, 5 denotes a valve, 6 denotes a pump, and 7 denotes a gas container. The heating coil 3 'is installed as necessary in consideration of the size of the tank and the like.

In the heat treatment of the waste, the waste and the additive are filled in a tank, sealed with a sealing lid to shut off the outside air, and the tank is placed in a heating source (heating coil) installed in advance. Insert and supply electric power to the heating coil to heat the entire tank and subject the waste to carbonization. Then, after the heat treatment for a predetermined time, the tank is taken out of the heating source and cooled, the gas in the tank is taken out, and the residue (processed ash) in the tank is taken out.

The gas may be withdrawn immediately after the tank is taken out from the heating source and then cooled, or the gas may be gradually removed while being heated by the heating source.

As described later, it has been found that alkali-based and / or silicate-based substances are suitable as additives which easily react with a chlorine component at a predetermined temperature. In the present invention, this additive is mixed with waste and filled in a closed tank, and the entire tank is heated to subject the waste to dry distillation.

By performing dry distillation in this way, the chlorine component is completely fixed to the treated ash (residue), and there is no chlorine component to be gasified. As an embodiment, as shown in FIG. 1 (A), an appropriate amount (5 to 30% by weight) of waste (garbage) and a substance of an alkaline system and / or a silicate is mixed in a tank 1 to reduce a chlorine component. As shown in FIG. 3B, the valve 5 is fixed to the treated ash so that the exhaust gas does not contain a chlorine component.
Is opened, and the pump 6 is operated to collect the gas in the gas container 7.

[0029] The gas is therefore a combustible gas (C _n H _m, etc.), it may be a new fuel that does not contain chlorine components by collecting the gas container 7. In addition, you may collect | recover during heating.

The following experimental investigation revealed that mixing of the waste in the tank with an additive of an alkaline and / or silicate substance reliably fixes the chlorine component.

In the experiment, first, the following simulated garbage which simulates standard city garbage is prepared.

20% by weight ・ Plastic (PE, PP, PS, PVDC) 50% by weight ・ Paper (tissue, newspaper, wrapping paper, box, drink pack) 20% by weight ・ 10% by weight of cloth (such as rag) ・ Kitchen The simulated garbage is crushed, and 8 g of the crushed simulated garbage is mixed with 1-2 g of two kinds of powdered calcium silicate and calcium hydroxide. And the concentration of hydrogen chloride gas (ppm) were measured. The heating temperature is 200 ° C, 250 ° C, 300 ° C,
The temperature was divided into seven stages of 350 ° C., 400 ° C., 500 ° C., and 600 ° C., and each temperature was maintained for 5 minutes to measure the hydrogen chloride concentration (gas concentration). The measurement of gas concentration is performed according to JIS-K080
The measurement was performed using the detector tube specified in No. 4.

Table 1 shows the measurement results. The measured values shown in Table 1 are average values of the measured values in 10 experiments.

In the table, “*” indicates that no chlorine component was detected in any of the ten experiments.

[0035]

[Table 1]

From the above results, it was found that calcium silicate reacted with the chlorine component in the low temperature range and calcium hydroxide in the high temperature range, so that the chlorine was reliably immobilized.

From this, when waste containing chlorine components is subjected to dechlorination by dry distillation, one or both of calcium silicate and calcium hydroxide are mixed depending on the temperature of the heat treatment to produce waste. It can be seen that when added, the chlorine component can be effectively fixed, and the gas generated during the heat treatment does not contain the chlorine component.

Therefore, even if this gas is released into the atmosphere,
Moreover, even if it burns, it is harmless and can be used effectively.

The reason why the calcium hydroxide reacts with the chlorine component in the high-temperature region and is fixed is that the waste gas-solid reacts with hydrogen chloride (HCL) generated during thermal decomposition, and alkali chloride @ Ca (CLO) ₂ 4H ₂ O · CaCL ₂ 4H ₂ O or the like is generated and the chlorine component is immobilized on the treated ash, and the same function and effect can be expected as long as it works in the same manner.

Accordingly, it is clear that similar results can be obtained with alkaline substances other than calcium hydroxide.

The following can be used as the alkaline substance.

(A) Alkaline earth metal compounds: calcium hydroxide, calcium oxide, calcium carbonate magnesium hydroxide, magnesium oxide, magnesium carbonate barium hydroxide hydrate, barium oxide, barium carbonate strontium hydroxide, strontium carbonate dolomide ( (CaCO ₃ .MgCO ₃ ) (b) Alkali metal compound: sodium hydroxide, potassium hydroxide, lithium hydroxide hydrate sodium carbonate, potassium carbonate, potassium sodium carbonate sodium carbonate hydrate, lithium carbonate The reason that calcium silicate is fixed by reacting with chlorine components in the area is that calcium silicate hydrate is porous, has a large specific surface area and contains water, and contacts and adsorbs hydrogen chloride gas generated during waste pyrolysis. To fix the chlorine component in the treated ash It is because it is, as long as it functions in the same manner, it is possible to anticipate the same operation and effect.

Therefore, it is clear that similar results can be obtained with silicates other than calcium silicate.

The following can be used as the silicate.

(A) Silicic acid hydrate: calcium silicate hydrate, magnesium silicate hydrate, dobamonide (5CaO
_{· 6Sio 2 · 5H 2 O)} (b) silicate chloride compound: aluminum silicate, as a result of the sodium silicate above experimental investigation, the addition amount is preferably added 5-30 wt% of the waste to be treated, also It was found that when the temperature in the carbonization treatment step was in the range of 200 ° C. to 600 ° C., the chlorine component was reliably fixed.

Next, since the chlorine component is fixed in the treated ash taken out of the tank and cannot be discarded or burned as it is, it is necessary to perform a dechlorination treatment. Regarding this dechlorination treatment, the applicant of the present invention has previously filed a patent application (Japanese Patent Application No. 7-319910), but as shown in FIG. 2, first, treated ash (residue) is put into a water tank. The chlorine component is dissolved in water by stirring for a predetermined time (about 30 minutes). Next, this is dewatered and separated, and the chlorine component is removed from the treated ash, which is dried and solidified. Separated wastewater is dechlorinated separately by wastewater treatment means.

The residual chlorine component of the solidified treated ash was measured by ion chromatography and found to be 1,000 pp
However, almost none at 5 ppm or less.

Further, depending on the physical properties of the residue, it is possible to separate the residue into various substances by a separating means, and to dry and solidify the separated substance to use the fuel or other effectively.

[0049]

As described above, according to the present invention, the closed tank is filled with additives and wastes, and the tank is inserted into a heating source to shut off the outside air to perform the heat treatment. The closed tank can be realized, for example, as a tank of the size of a drum. (2) In addition, the waste can be sealed and temporarily stored in the tank. (3) The chlorine component is fixed to the treated ash, Since there is no component, it can be released or used as it is, and the post-treatment of treating the gas after the heat treatment with a filter or the like is not necessary. (4) Further, the chlorine component fixed to the treated ash is: Since it can be effectively removed (almost none) by washing with water, etc., waste can be easily treated,
Since no special large-scale equipment is required, waste treatment can be performed with an extremely small-scale waste treatment facility, and installation at facilities (towns, villages, general companies, specific facilities) that generate less than 10 tons / day of waste is possible. It can be realized and contributes to solving environmental issues, and has excellent effects such as being able to contribute.

[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 a separation process of treated ash.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Tank 2 ... Opening / closing lid 3 ... Heating coil 4 ... Exhaust pipe 5 ... Valve 6 ... Pump 7 ... Gas container

Claims (6)

[Claims] 1. Filling a waste with an additive that reacts with a chlorine component at a predetermined temperature into a tank having an openable and closable lid, inserting the entire tank into a heating source, and heating the waste to carbonize the waste. A batch-type waste dechlorination treatment method comprising treating and fixing a chlorine component to a treated ash so that the generated gas does not contain a chlorine component. 2. The batch-type waste dechlorination method according to claim 1, wherein the heating source is formed in a cylindrical shape, and a tank is inserted into the heating source to heat the tank. 3. The batch-type waste dechlorination method according to claim 1, wherein the heating source is an induction heating coil. 4. The batch-type waste dechlorination method according to claim 1, wherein the tank is made of a magnetic material. 5. A step of filling a closed tank with waste and additives, a step of inserting the tank into a heating source, a step of heating the entire tank and subjecting the waste to dry distillation, and a step of removing the tank from the heating source. A batch type waste dechlorination treatment method, comprising a step of removing the treated ash from a cooled tank. 6. The batch-type waste dechlorination method according to claim 1, wherein the additive is an alkaline substance and / or a silicate which easily reacts with a chlorine component.