JPH11267607A - Treatment of waste and device therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce a cost for treating the waste by slurrying a solid waste containing a halogen-containing resin such as vinyl chloride, subjecting the obtained slurry to a hydrothermal reaction in a reactor, then subjecting the resulting medium to flashing and dehydration treatment, subjecting a part of a filtrate to an electrolytic treatment and subjecting a residual filtrate to an electrolytic oxidation treatment. SOLUTION: The solid waste containing the halogen-containing resin such as vinyl chloride is mixed with an alkali aq. soln. 28, etc., by a pretreating means 10 and also ground to obtain the slurry from which a useful inorg. matter such as iron and aluminum is separated. Then the slurry is pressurized with a pump 13, and after subjecting the slurry to the hydrothermal reaction, the slurry is flashed into a flash evaporator 20 to reduce pressure to the atmospheric pressure to generate a saturated steam. Then the reaction slurry is dehydrated with a separation means 24 to be concentrated and separated into a fuel cake 27 and a filtrate 29. A part of the filtrate 29 is subjected to the electrolytic treatment with an electrolytic means 26 and also the residual filtrate is subjected to the electrolytic oxidation treatment with the electrolytic oxidation means 70.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to dewatering of organic solids such as municipal solid waste and industrial wastes, especially waste slurries containing a large amount of vinyl chloride and other chlorine-containing resins, after a hydrothermal decomposition reaction. A waste that is converted into a cake that has been converted into a fuel, and a part of the filtrate is electrolytically treated to produce an alkaline aqueous solution for circulating use, while the remaining filtrate is treated for COD substances and BOD substances by electrolytic oxidation means. And a device therefor.

[0002]

2. Description of the Related Art Solid waste such as general waste such as municipal solid waste and industrial waste discharged from factories and the like is increasing year by year. I have. From such a point of view, after crushing solid waste in water and recovering useful materials such as iron, aluminum and glass that can be recycled in the form of a water slurry,
Dehydration to a state having an appropriate moisture value, and then high-pressure, high-temperature reaction slurry obtained by hydrothermal reaction for a predetermined residence time under high-pressure, high-temperature conditions is finally depressurized to atmospheric pressure To obtain the product slurry.

[0003]

However, when treating municipal waste or industrial waste containing a large amount of vinyl chloride or other chlorine-containing resin, there are the following problems. When municipal solid waste or industrial waste containing a large amount of vinyl chloride or other chlorine-containing resin is incinerated, dioxin, a highly toxic substance, may be generated, which poses a problem from the viewpoint of environmental protection. Further, when burning waste containing a large amount of vinyl chloride or other chlorine-containing resin, Cl ₂ or HCl is generated during the combustion, and corrosion problems are likely to occur in a subsequent air preheater, a waste heat recovery boiler, or the like. Waste containing organic chlorine compounds can be dechlorinated by hydrothermal reaction, but the resulting hydrochloric acid and alkali salts (sodium chloride) are highly corrosive and have a limited solubility. Must be discharged outside the system so that it does not accumulate. COD for draining the filtrate into public waters as wastewater
(Chemical oxygen demand) Wastewater treatment equipment mainly for removal and treatment costs are required, and thus the costs are high. Further, in the method of crystallizing and separating sodium chloride in the filtrate by evaporation and concentration, a large amount of heat energy is required because most of the water is evaporated. To neutralize municipal waste or industrial waste containing a large amount of vinyl chloride or other chlorine-containing resin once as a waste slurry, a large amount of an alkaline substance such as NaOH is required, leading to high running costs and economical efficiency. Not.

The present invention has been made in view of the above problems, and an object of the present invention is to convert a waste slurry containing a large amount of vinyl chloride or other chlorine-containing resin into a fuel by dehydration after a hydrothermal decomposition reaction. And a method for treating waste, in which a part of the filtrate is electrolytically treated and circulated and used as an aqueous alkaline solution, and the remaining filtrate is treated with COD and BOD substances by electrolytic oxidation means. It is to provide a device.

[0005]

In order to achieve the above object, according to a first aspect of the present invention, a solid waste containing a large amount of vinyl chloride or other chlorine-containing resin is treated by a pretreatment means. A method for treating a waste in which a slurry is formed, and the slurry is hydrothermally reacted in a reactor to obtain a reaction slurry, and then dewatered after flashing to obtain a cake-like dechlorinated raw fuel and a filtrate. In this case, a part of the filtrate is subjected to electrolytic treatment, and the remaining filtrate is subjected to electrolytic oxidation treatment.

In the second invention, which is mainly based on the first invention, a part of the filtrate is subjected to electrolytic treatment to separate it into chlorine gas, hydrogen gas and an aqueous alkali solution, and the separated aqueous alkali solution is used as a waste slurry. Circulating as a neutralizing agent for
The remaining filtrate was subjected to electrolytic oxidation treatment so that COD and BOD substances in the filtrate were separated into wastewater and hydrogen gas in which the amount was reduced.

Further, in the third invention mainly based on the first invention, when the solid waste contains a large amount of vinyl chloride or other chlorine-containing resin, the entire amount of the filtrate is electrolytically treated by the electrolytic means. If the solid waste contains a medium amount of vinyl chloride or other chlorine-containing resin, a part of the filtrate is electrolytically treated to obtain an aqueous alkali solution, and then the pretreatment means or the downstream side of the mixing tank is used. At the same time, the remaining filtrate is sent to the pretreatment means by bypassing the electrolytic means.If the solid waste contains a small amount of vinyl chloride or other chlorine-containing resin, the alkali aqueous solution is used. The amount required for neutralization was fed to the downstream side of the mixing tank from the stored alkaline aqueous solution tank.

In the fourth invention, solid waste containing a large amount of vinyl chloride or other chlorine-containing resin is converted into a waste slurry by a pretreatment means, and the slurry is hydrothermally reacted in a reactor to form a reaction slurry. After obtaining, a waste treatment apparatus in which a cake-like dechlorinated raw fuel and a filtrate are obtained by dehydrating and dehydrating subsequent to a flash, and an electrolytic means capable of electrolytically treating a part of the filtrate, An electrolytic oxidation means capable of electrolytically oxidizing the COD substance and the BOD substance in the remaining filtrate was provided.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A concrete embodiment of the method and apparatus for treating waste according to the present invention will be described below with reference to FIGS.
This will be described in detail with reference to FIG.

FIG. 1 is a block diagram of a system configuration according to an embodiment of the present invention, FIG. 2 is a system block diagram in which a filtrate is subjected to electrolytic treatment using an electrolytic device by an ion exchange membrane method, and FIG. 3 is an electrolytic device by a diaphragm method. , A system block diagram in which a filtrate is subjected to electrolytic treatment, FIG. 4 is a system configuration block diagram of an actual embodiment when a small amount of vinyl chloride is contained in solid waste, FIG. 5 is a system block diagram of a second case, FIG. 6 is a system block diagram of the third case.

FIG. 1 will be described in detail below. First, wastes containing organic solids that have been collected from various places and that are in an unsorted state are pretreated, and then supplied to the thermal decomposition process. In particular, in the present invention, waste containing a large amount of vinyl chloride and other chlorine-containing resins is supplied to the pretreatment step.

In the pretreatment step, when treating wastes containing a large amount of vinyl chloride and other chlorine-containing resins which are basically unsorted, useful substances such as recyclable iron, aluminum and glass are contained. Therefore, it is necessary to collect the waste first and to make the solid waste into a slurry that can be transported for the continuous operation of the solid waste treatment system. A pretreatment means 10 for this purpose is provided, and this pretreatment means 10 is composed of a crushing device, a separation device for useful materials, a dewatering device, and the like.

Therefore, in the pretreatment means 10, solid waste containing organic solid matter in an unsorted state is made into a water slurry by crushing in water, and in this slurrying step, non-combustible substances contained in the crushed material are formed. By utilizing the difference in specific gravity of materials, useful materials such as recyclable iron, aluminum, and glass are collected. Then, the water slurry containing the organic solid matter from which the incombustible matter has been removed is dehydrated to a solid matter content of about 8 to 20% by weight, and is adjusted to have a viscosity enough to be conveyed to the subsequent processing step. I have.

The waste slurry treated by the pretreatment means 10 is temporarily stored in a storage tank 12, where it forms a buffer between the treatment by the pretreatment means 10 and the subsequent processing. The waste slurry discharged from the storage tank 12 contains an alkaline aqueous solution 2
8 has been added. The waste slurry in the storage tank 12 is supplied to the subsequent reactor 14 as a waste slurry mixed with a base by a pumping means such as a high-pressure pump 13 so that the hydrothermal reaction is performed while flowing through the reactor 14. Is caused.

The operating temperature in the reactor 14 is from 250 to 350
The temperature is raised to an appropriate temperature of about
The slurry is fed while being pressurized to about 170 atm by step 3, and the temperature is raised in advance to the reaction temperature before the reactor 14. In the embodiment, the first heat exchanger 16 and the second heat exchanger are used. The temperature is raised stepwise to the reaction temperature at 18 before being fed to the reactor 14. As a result, the waste slurry thus heated is maintained at the reaction temperature in the course of passing through the reactor 14 and at a pressure higher than the saturated steam pressure of the reaction temperature for a reaction time of several minutes to tens of minutes. Is thermally decomposed by a hydrothermal reaction.

In the present embodiment, the reaction slurry after the hydrothermal reaction in the reactor 14 uses a flash evaporator 20 as a cooling device and supplies steam generated by flash evaporation to the first heat exchanger 16. ing. That is, the temperature is raised stepwise to the reaction temperature, and then sent to the reactor 14, a hydrothermal reaction is performed under predetermined operating conditions, and steam flashed by isenthalpy expansion using the flash evaporator 20 is used. It is supposed to. In order to increase the efficiency of such heat recovery, it is desirable to reduce the flash pressure in several stages. Further, by compressing the flash steam (for example, by heat pump), the efficiency of heat recovery can be further improved.

Further, the reaction slurry from the reactor 14 is flushed to a flash evaporator 20 and reduced in pressure to the atmospheric pressure. At this time, steam is generated. In the process of concentrating the reaction slurry stored in the flash evaporator 20 by a centrifugal separator or the like constituting the separation means 24, a filtrate 29 containing dissolved gas, salt and the like, and a dechlorinated fuel cake 27 are obtained. Of these, the fuel cake is burned in the heating medium heating furnace 34,
The heat medium circulating between the second heat exchanger 18 and the heat medium heating furnace 34 is heated by the combustion heat. Since the flash steam after heating the waste slurry mixed with the base in the first heat exchanger 16 is condensed, the condensed liquid is separated by the separation means 2.
It is used as a washing liquid for the fuel cake 27 obtained by separation in step 4.

When the condensate is washed, the mother liquor containing chlorine ions in the fuel cake 27 is replaced by the condensate, and a dechlorinated fuel cake 27 containing 20 to 60% by weight of combustible water is obtained. . Although the condensate is used as the cleaning liquid for the fuel cake 27, the first heat exchanger 1 is used in consideration of the case where the condensate alone is insufficient as the cleaning liquid.
It is desirable to provide a supply line for make-up water in the middle of the flash steam condensing line connected from 6 to the separating means 24.

The waste slurry is hydrothermally reacted in the reactor 14, and the obtained reaction slurry is separated by the separation means 24 to obtain the fuel cake 27 and the filtrate 29. Depending on the ratio of the amount of the chlorine-based resin contained in the waste, a part (X) of the filtrate 29 separated by the separation means 24 is fed to the electrolytic oxidation means 90 to carry out the electrolytic treatment, or The remaining liquid (Y) of 29 is sent to the electrolytic means 26 to determine whether or not to perform the processing. That is, when the amount of vinyl chloride in the municipal solid waste or the industrial waste is large, a large amount of the alkaline aqueous solution 28 serving as a neutralizing solution is required. By reducing the amount of (X) and increasing the amount of the remaining filtrate 29 (Y), the electrolytic solution 26 is used for the treatment, so that the alkaline aqueous solution 28 is secured.

As shown in FIG. 1, the filtrate 29 (Y) sent to the electrolytic means 26 is subjected to an electrolytic reaction. The filtrate 29 is separated into chlorine gas, hydrogen gas and an aqueous alkaline solution 28 by electrolytic treatment. As such electrolytic means 26,
For example, an electrolysis method using an ion exchange membrane method or an electrolysis method using a diaphragm method can be considered.

First, an electrolytic apparatus using the ion exchange membrane method will be described with reference to FIG. Reference numeral 36 denotes an electrolytic device,
It comprises an ion exchange membrane 38, an anode 40 and a cathode 42, which are arranged in parallel with each other. An ion exchange membrane 38 is stretched from one end of the electrolysis device 36 to the other end so as to divide the electrolysis device 36 into two parts, and is divided into two parts to form an anode chamber 46 and a cathode chamber 48. A return pipe 44 having a U-shape communicating the anode chamber 46 and the cathode chamber 48 is provided on the other end side opposite to the inlet where the filtrate 29 is introduced into the electrolytic device 36.

An anode 40 is provided in the anode chamber 46 leading to the inlet of the filtrate 29 along the longitudinal direction of the anode chamber 46. When the filtrate 29 flows, chlorine gas is generated by an electrode reaction. I have. A cathode 42 is provided along the longitudinal direction of the cathode chamber 48 in the cathode chamber 48 having an outlet for the alkaline aqueous solution 28 generated after one electrolysis, and when the filtrate 29 flows, hydrogen gas is generated by an electrode reaction. It has become. On the other hand, as the ion exchange membrane 38, a cation type is usually used. After generating chlorine gas from the anode 40, alkali metal ions such as Na move to the cathode chamber 48 through the ion exchange membrane 38. As a result, sodium hydroxide (NaOH) is generated, and finally, the filtrate 29 is electrolyzed to become an alkaline aqueous solution 28 which is a decomposition solution. Note that, as described above, the alkali metal is not limited to the example of Na, and similar results can be obtained with K, for example.

As described above, the case where a cationic type is used as the ion exchange membrane 38 has been described. However, the present invention is not limited to the cationic type, and an anionic type may be used. In the case where an anionic material is used, the filtrate 29 is supplied to the cathode chamber 48 unlike the case of supplying the filtrate 29 to the anode chamber 46 side like a cationic material. The filtrate 29 supplied to the cathode 42 generates hydrogen gas by an electrode reaction and generates chlorine gas from the anode 40, and then alkali metal ions such as OH pass through the ion exchange membrane 38 to the anode chamber 46. The movement causes sodium hydroxide (NaOH) to be generated, and finally, the filtrate 29 undergoes an electrode reaction to become an alkaline aqueous solution 28 which is a decomposition solution.

Next, an electrolyzer using a diaphragm method will be described with reference to FIG. Reference numeral 50 denotes an electrolysis device, which is composed of a diaphragm 52 made of unglazed or asbestos, an anode 54 and a cathode 56, and is arranged in parallel. A diaphragm 52 is stretched from the one end to the other end of the electrolysis device 50 so as to divide the electrolysis device 50 into two parts through the axial center portion, and is divided into two to form an anode chamber 58 and a cathode chamber 60. . Further, the anode chamber 58 constituting the electrolysis apparatus 50 has an inlet for the filtrate 29 at one end thereof, and the cathode chamber 60 has an outlet for the alkaline aqueous solution 28 on the side opposite to the inlet.

An anode 54 is provided along the longitudinal direction of the anode chamber 58 in the anode chamber 58 communicating with the inlet of the filtrate 29. When the filtrate 29 flows, chlorine gas is generated by electrolysis. . A cathode 56 is disposed along the longitudinal direction of the cathode chamber 60 having an outlet for the alkaline aqueous solution 28 generated after one electrolysis.
On the other hand, with respect to the diaphragm 52, the filtrate 29 which has been introduced from the inlet and subjected to an electrode reaction at the anode 54 passes through the diaphragm 52,
Subsequently, it moves to the cathode chamber 60 to generate hydrogen gas by an electrode reaction, and hydrogen ions are removed to form an aqueous alkaline solution 28, which is discharged from the outlet of the cathode chamber 60.

Incidentally, raw material waste such as municipal waste contains a large amount of vinyl chloride and other chlorine-containing resins, and the chlorine compound generates hydrogen chloride upon thermal decomposition. Therefore, as described later, the waste slurry to which the base has been added and the reaction slurry obtained by hydrothermally reacting the slurry in the reactor 14 are separated by the separation means 24 to form the fuel cake 27 and the filtrate 29. However, when a part (Y) of the filtrate 29 is fed to the electrolysis means 26 and electrolyzed, chlorine gas,
It is separated into hydrogen gas and aqueous alkaline solution 28. The alkaline aqueous solution 28 is stored in the alkaline aqueous solution tank 30.
Is temporarily stored in the wastewater slurry, and an aqueous alkaline solution 28 is added to the waste slurry subjected to the hydrothermal reaction to neutralize the hydrogen chloride generated during the hydrothermal reaction.

An aqueous alkaline solution 28 which is an alkaline substance
Is added for the purpose of preventing corrosion of liquid-contacting parts such as reactors, heat exchangers, and other piping due to generation of hydrochloric acid and the like by the reaction. Alkaline aqueous solution tank 30
The alkaline substance supplied through the alkaline aqueous solution supply pump 32 is continuously injected, and the injection amount is an amount necessary for neutralizing the generated hydrogen chloride. When the content is large, it is necessary to increase the alkali concentration or the addition amount of the alkaline aqueous solution 28.

The alkali concentration of the alkaline aqueous solution 28 is controlled by the amount of electric current for electrolysis, and the injection position is such that the alkaline solution is injected into the storage tank 12 and the high-pressure pump 13 immediately downstream of the storage tank 12. May be directly supplied to the pretreatment means 10 or the storage tank 12. In addition, the alkaline aqueous solution supply pump 32 adjusts the pH of the reaction product.
It is a variable pump so that it can be adjusted by the value.

On the other hand, when the remaining filtrate 29 (X) is fed to the electrolytic oxidation means 70 and electrolyzed, the COD substance and the BOD substance in the filtrate 29 are electrolytically oxidized, and hydrogen gas and COD
Material and BOD material are separated into greatly reduced wastewater.

The specific contents of a treatment method using such a waste treatment system will be described.

A so-called solid waste containing a large amount of vinyl chloride or other chlorine-containing resin in an organic solid such as municipal solid waste or industrial waste is introduced into a treatment system without being mixed. The unsorted waste is mixed with the alkaline aqueous solution 28 or the filtrate 29 in the first pretreatment means 10, and
The slurry is pulverized into an aqueous slurry, from which useful inorganic substances such as iron and aluminum are separated to produce a waste slurry containing organic solids.

In the pulverization process, several m of solids are obtained by crushing in water.
m, so that an aqueous slurry is obtained, and iron and the like are separated and removed during crushing in water. This aqueous slurry is then charged into a cyclone,
Here, useful materials such as aluminum and glass are separated, and the slurry containing the organic solid is adjusted to have a water content (about 14% by weight) to such an extent that it can be pumped through a dewatering device, and the storage tank 12 To The pre-treated basic waste slurry is supplied to the reactor 14 by the high pressure pump 13.
Sent to

In the present invention, solid waste is allowed to contain a large amount of an organic chlorine-based resin such as vinyl chloride which generates hydrogen chloride upon thermal decomposition. Hydrogen chloride generated in the reactor 14 is an alkaline aqueous solution 28 as an alkaline substance.
To perform a neutralization treatment.

The aqueous alkali solution 28 is supplied to the reactor 1
The pH of the reaction slurry at the outlet of No. 4 is a weakly acidic pH = 3 to
The injection amount (the alkali concentration in the alkaline water) may be adjusted so as to be 6, preferably 4 to 6. By controlling the electrolytic current so that the pH of the reaction slurry at the outlet of the reactor 14 becomes weakly acidic, continuous operation of the treatment of the composite waste becomes possible. In addition, the outlet pH of the reactor 14 is detected by changing the alkali concentration and the addition amount of the alkaline aqueous solution 28 according to the amount of vinyl chloride or other chlorinated resin in the solid waste to be treated, and the amount is adjusted to a predetermined addition amount. Can be adjusted.

The waste slurry in which the alkaline aqueous solution 28 has been injected into the waste slurry fed by the high-pressure pump 13 is heated to the reaction temperature before being supplied to the reactor 14, and the reaction temperature is increased from room temperature. 250-3 which is the temperature
Heat to 50 ° C. For this reason, the first heat exchanger 16,
A second heat exchanger 18 is disposed upstream of the reactor 14 path;
The temperature of the first heat exchanger 16 and the second heat exchanger 18 is increased stepwise. First heat exchanger 16, second heat exchanger 18
Is preheated by the heat of the flash steam generated when the waste slurry is flashed from the reactor 14 to the flash evaporator 20, and then the waste slurry is passed between the heating medium heating furnace 34 and the second heat exchanger 18. The temperature is raised to a reaction temperature of 250 to 350 ° C., desirably about 325 ° C. by a circulating heat medium, and is introduced into the reactor 14.

This slurry is held for several tens of minutes in the reactor 14, and the liquid pressure is higher than the saturated vapor pressure at that temperature to prevent boiling. The reaction slurry from the reactor 14 is flushed to the flash evaporator 20 and reduced in pressure to atmospheric pressure, at which time saturated steam is generated. The reaction slurry stored in the flash evaporator 20 is concentrated through a centrifugal filter or the like constituting the separating means 24, and is concentrated in the process of washing the fuel cake 2 washed with the flash condensate.
7 and the filtrate 29.

Here, a part (X) of the amount of the filtrate 29 separated by the separation means 24 is supplied to the electrolytic oxidation means 90 depending on the amount of vinyl chloride in the municipal waste or industrial waste as the raw material of the present invention. Feed and electrolyze or filtrate 2
The remaining liquid (Y) of No. 9 is sent to the electrolytic means 26 to determine whether or not to perform the processing. That is, when the amount of vinyl chloride in the municipal solid waste or the industrial waste is large, an alkaline aqueous solution 28 serving as a neutralizing solution is required.
, And more alkaline aqueous solution 28 is obtained by electrolysis. It is desirable that the filtrate 29 (X) fed to the electrolytic oxidation means 90 be fed in such an amount as to balance water in the system.

The filtrate 29 (Y) sent to the electrolytic means 26
Is subjected to an electrolytic reaction. In the electrolysis device 36 using the ion exchange membrane 38 as the electrolysis means 26, the filtrate 29 introduced into the anode chamber 46 constituting the electrolysis device 36 generates chlorine gas by the anode 40 and, for example, an alkali such as Na ion. The metal is passed through the ion exchange membrane 38 and the cathode 42
To the cathode chamber 48 having Thus, the remaining filtrate 29 in the anode chamber 46 from which sodium chloride (NaCl) has been removed is introduced into the cathode chamber 48 having the cathode 42 through the return pipe 44.

At the cathode 42, hydrogen gas is generated from hydrogen ions, and hydroxyl ions remain in the anode chamber 46. As described above, alkali metal (Na) ions enter the cathode chamber 48 through the ion exchange membrane 38 from the anode chamber 46, so that a base (NaOH) is generated. The solution is supplied to the aqueous solution tank 30.

On the other hand, in the electrolytic device 50 using the diaphragm method shown in FIG. 3, the filtrate 29 introduced into the anode chamber 58 constituting the electrolytic device 50 generates chlorine gas by the anode 54. The remaining filtrate 29 passes through the diaphragm 52 and moves to the cathode chamber 60. At this time, the alkaline aqueous solution 28 after the hydrogen gas is generated by the cathode 56 in the cathode chamber 60 is discharged from the outlet of the cathode chamber 60, It is fed to the alkaline aqueous solution tank 30.

The remaining filtrate 29 (X) is supplied to the electrolytic oxidation means 70
Sent to In the electrolytic oxidizing means 70, an electrolytic cell using an electrode insoluble in an aqueous sodium chloride solution (electrolytic solution), for example, an electrolytic cell for generating hypochlorous acid for seawater or tap water is used. The COD substance and the BOD substance, which are reducing substances, are simultaneously subjected to oxidation by direct electrolytic reaction and oxidation by sodium hypochlorite generated by the following formula. _{^{That, 2Cl - → Cl 2 + 2e}} - 2NaOH + Cl 2 → NaClO + NaCl + H 2 O

By such treatment, COD in the filtrate 29
The substance is discharged out of the system as wastewater reduced to about 100 ppm or less from 1-2%. The filtrate 29
When electrolytic oxidation is performed by the electrolytic oxidation means 70, hydrogen gas is generated. Such a by-product hydrogen gas may be recovered as a chemical raw material and used for other purposes.

Conversely, as shown in FIG. 4, when the amount of vinyl chloride in municipal solid waste and industrial waste is medium, a certain amount of the alkaline aqueous solution 28 serving as a neutralizing solution is required. The amount of the filtrate 29 (X) to be fed to the electrolytic oxidation means 70 is reduced, and the remaining filtrate 29 (X) is reduced.
A part of the filtrate 29 (Y ₁ ) of (Y) is treated by the electrolytic means 26, and the remaining filtrate 29 (Y ₂ ) is treated by the electrolytic means 26.
Alternatively, the replenishing water for slurry may be directly supplied to the pre-processing means 10 without passing through to reduce the amount of replenishing water for slurry.

If the amount of vinyl chloride in the municipal solid waste or industrial waste is small, the filtrate 29 is supplied to the electrolytic oxidation means 9.
And the remaining filtrate 29 (Y) is stored in an alkaline aqueous solution tank 30 via the electrolytic means 26, and then only a necessary amount of the alkaline aqueous solution 2 is contained in the waste slurry.
8 can be supplied. In the above example, the steam generated by flash evaporation of the reaction product slurry from the reactor 14 by the flash evaporator 20 is used as the first steam.
The slurry is supplied to the heat exchanger 16 to preheat the slurry,
The fuel cake 27 obtained by the centrifugal separation by the separating means 24 is preheated to the waste slurry by the heated heat medium while circulating between the second heat exchanger 18 and the heat medium heating furnace 34. However, as shown in FIG. 5, it can be used as a system obtained by adding a self-heat exchange system to the system shown in FIG.

Further, as shown in FIG. 6, based on the system shown in FIG. 1, the reaction slurry is once passed through a cooler 31 in order to effectively use the sensible heat of the reaction slurry at the outlet of the reactor 14. In order to use the medium for heating and energizing, a system in which a cooler 31 is provided at the subsequent stage of the reactor 14 and the heat medium is circulated and heated by the heat medium circulation pump 25 between the third heat exchangers 19 may be used. .

In the above example, the steam generated by flash evaporation of the reaction slurry from the reactor 14 by the flash evaporator 20 is supplied to the first heat exchanger 16 so as to preheat the slurry, and the separation means 24 The fuel cake 27 obtained by centrifugation is separated into the second heat exchanger 18
The mixed waste slurry is preheated by the heated heating medium while circulating between the heating medium heating furnace 34 and the first heating medium.
While the heat exchanger 16 is divided into multiple stages, flash is performed in multiple stages to obtain steam with different pressures, and the steam is supplied to each stage of the first heat exchanger 16 configured in multiple stages to increase the amount of heat recovery. Is also possible. Further, by providing a vapor compressor and pressurizing the flash steam, it is possible to increase the condensation temperature and increase the heat recovery.

[0047]

As apparent from the above description, the present invention has the following advantages. That is, since an alkaline aqueous solution for making the pH of the slurry discharged from the reactor weakly acidic is generated in the system, it is not necessary to newly supply NaOH for neutralization from the outside, and the waste disposal cost is reduced. . Since the amount of heat supplied from the outside can be reduced and the decomposition reaction is remarkably promoted, the solid waste is solidified into carbon, and can be effectively used as an alternative fuel or a gasification source. In addition, by using part of the system as a heating source, the amount of heat supplied from the outside can be reduced. Chlorine gas as a useful substance can be recovered and used as a chemical raw material such as hydrochloric acid, and hydrogen gas can be obtained as a by-product, thereby expanding the range of use for other uses. The amount of COD substances and BOD substances in the wastewater is zero or small, and the cost of wastewater treatment can be greatly reduced.

[Brief description of the drawings]

FIG. 1 is a system configuration block diagram of an embodiment according to the present invention.

FIG. 2 is a system block diagram in which a filtrate is subjected to electrolytic treatment using an electrolytic device using an ion exchange membrane.

FIG. 3 is a system block diagram in which a filtrate is subjected to electrolytic treatment using an electrolytic device using a diaphragm.

FIG. 4 is a block diagram of a system configuration of an actual embodiment when a small amount of vinyl chloride is contained in solid waste.

FIG. 5 is a system block diagram of a second case.

FIG. 6 is a system block diagram of a third case.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Pre-processing means 12 Storage tank 13 High pressure pump 14 Reactor 16 1st heat exchanger 18 2nd heat exchanger 19 3rd heat exchanger 20 Flash evaporator 24 Separation means 25 Heat medium circulation pump 26 Electrolysis means 27 Fuel cake 29 Filtrate 30 Alkaline aqueous solution tank 31 Cooler 32 Alkaline aqueous solution supply pump 34 Heat medium heating furnace 36 Electrolyzer 38 Ion exchange membrane 40 Anode 42 Cathode 44 Return pipe 46 Anode chamber 48 Cathode chamber 50 Electrolyzer 52 Partition membrane 54 Anode 56 Cathode 58 Anode chamber 60 cathode room 70 electrolytic oxidation means

Claims (4)

[Claims] 1. A solid waste containing a large amount of vinyl chloride or other chlorine-containing resin is converted into a waste slurry by a pretreatment means, and the slurry is hydrothermally reacted in a reactor to obtain a reaction slurry. A method for treating a waste material in which a cake-like dechlorinated raw fuel and a filtrate are obtained by dehydration subsequent to flashing to obtain a cake-like dechlorinated raw fuel, wherein a part of the filtrate is subjected to electrolytic treatment and the remaining filtrate is subjected to electrolytic oxidation treatment. A method for treating waste, characterized in that: 2. A part of the filtrate is subjected to electrolytic treatment to separate into a chlorine gas, a hydrogen gas and an aqueous alkaline solution, and the separated aqueous alkaline solution is used as a neutralizing agent for a waste slurry, and the remaining filtrate is used as a neutralizer. COD in filtrate after electrolytic oxidation
2. The method for treating waste according to claim 1, wherein the substance and the BOD substance are separated into wastewater and hydrogen gas in which the amount is reduced. 3. When the solid waste contains a large amount of vinyl chloride or other chlorine-containing resin, the entire amount of the filtrate is subjected to electrolytic treatment by electrolytic means, and the solid waste contains vinyl chloride or other chlorine-containing resin. When the system resin is contained in an intermediate amount, a part of the filtrate is subjected to electrolytic treatment to obtain an alkaline aqueous solution, and then the remaining filtrate is supplied to the downstream side of the pretreatment means or the mixing tank and the remaining filtrate is bypassed through the electrolytic means. When the solid waste contains a small amount of vinyl chloride or other chlorinated resin, the amount necessary for neutralization is mixed from the alkaline aqueous solution tank storing the alkaline aqueous solution. 2. The method for treating waste according to claim 1, wherein the waste is supplied to a downstream side of the tank. 4. A solid waste containing a large amount of vinyl chloride or other chlorine-containing resin is converted into a waste slurry by a pretreatment means, and the slurry is hydrothermally reacted in a reactor to obtain a reaction slurry. What is claimed is: 1. A waste treatment apparatus in which dewatering is performed after a flush to obtain a cake-like dechlorinated raw fuel and a filtrate, wherein an electrolysis means capable of electrolytically treating a part of the filtrate, And an electrolytic oxidation means capable of electrolytically oxidizing the COD substance and the BOD substance.