JP2001302293A - Method of treating waste - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase the use of the solid component without damage to the quality of the produced cement M and corrosion of the production apparatus 6 and the like, when the pyrolyzate solid component after pyrolysis of the waste A is used as a raw material or a part of the fuel. SOLUTION: The solid components including char E and ash G are separated from the pyrolytic product from waste A, water H, acid I and carbonic acid gas are added to the resultant solid components to form a slurry, and then the slurry is dehydrated and fed to the cement production means 6 after being dried.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for treating waste, in which a solid content including char and ash among pyrolysis products of waste such as municipal garbage is used as a raw material or fuel in cement production. Things.

[0002]

2. Description of the Related Art Conventionally, waste such as municipal garbage has been incinerated in an incineration facility, and then the incinerated ash is disposed of in a landfill. The incineration ash is melted and processed in a melting facility. Also recently,
In this way, the waste is melt-processed, and the waste is thermally decomposed in a pyrolysis facility to produce a flammable pyrolysis gas and a solid containing char and ash, and the char and pyrolysis gas are generated. There are also proposals in which high combustion energy is used for melting ash.

[0003]

However, the waste melt thus obtained is cooled and converted into a stone, and only a part thereof is used as a construction material such as an aggregate. Is not being used effectively. On the other hand, the ash in the solid content of the incineration ash discharged from the incineration equipment and the product generated in the pyrolysis equipment contains a sufficient amount of a component that can be used as a raw material for cement. The combustion energy of the char in the fraction can be used as heat energy for firing the cement. Thus, the inventors of the present invention supply the solid content of the product obtained by thermally decomposing the waste to a cement manufacturing means such as a kiln, so that the solid content can be used as a raw material or a part of fuel during the cement production. We examined whether it could be used.

[0004] However, while the solid content in the product obtained by thermally decomposing waste such as municipal waste contains ash as a cement raw material as described above, the quality of the cement such as chlorine, sodium and potassium is deteriorated. Components that cause deterioration are also included, and if such components are contained in the product cement in a large amount, the structure formed by the cement may become brittle and easily cause peeling or the like. Even if this solid content is used as a raw material for cement, the usable amount must be naturally limited. Further, among these components, particularly chlorine may be discharged together with the exhaust gas from the cement manufacturing kiln and cause corrosion or the like in a subsequent exhaust gas treatment facility, or may corrode the kiln itself.

[0005] The present invention has been made under such a background, and is intended to be used in the case where the solid content of a product obtained by thermally decomposing waste is used as a raw material or a part of fuel in cement production. It is an object of the present invention to provide a waste treatment method capable of increasing the use amount of the solid content without deteriorating the quality of the used cement or causing corrosion of the cement production means and the like.

[0006]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems and achieve such an object, the present invention provides a method for separating a solid content containing char and ash from a product obtained by pyrolyzing waste, Water, an acid, and carbon dioxide are added to the solid content to form a slurry, and then the slurry is dewatered and dried, and then supplied to a cement production means.
Therefore, by adding water, an acid, and carbon dioxide gas to form a slurry, components such as chlorine, sodium, and potassium are eluted in the liquid component in the solid content, and the slurry is dehydrated. By removing these components and drying to make a cement manufacturing means such as a kiln, a large amount of solids can be used as a raw material or fuel for cement production without causing deterioration of quality due to the above components. It can be used as

[0007]

FIG. 1 shows a waste treatment facility according to one embodiment of the waste treatment method of the present invention. The treatment method of the present invention will be described below with reference to FIG. An embodiment will be described. In FIG. 1, reference numeral 1 denotes a fluidized bed type pyrolysis furnace. Slaked lime B is added to waste A containing organic matter and supplied to the pyrolysis furnace 1, and the pyrolysis is performed. A flowing gas C is supplied from a pressurizing chamber 1A formed at the lower part of the furnace 1. In the pyrolysis furnace 1, a part of the organic matter of the waste A is burned, and most of the remaining is pyrolyzed to generate a pyrolysis gas D and a char E. Further, at this time, the chlorine component contained in the waste A is thermally decomposed in the pyrolysis furnace 1 to temporarily form hydrogen chloride, and then neutralized by the slaked lime B to form calcium chloride. Sodium or potassium chloride is formed by the sodium or potassium component to generate chloride F.

[0008] In this way, the products generated by pyrolysis of the waste A in the pyrolysis furnace 1, that is, the pyrolysis gas D, the char E, the chloride F, the ash of the burned waste A and excess slaked lime The ash G, which is composed of quicklime and B produced by heating B, is mixed with the flowing gas C in this pyrolysis furnace
Is sent to a separation means 2, such as a cyclone, from the top of the tank, and is separated into a gas component (flowing gas C and pyrolysis gas D) and a solid component (char E, chloride F, and ash G).

The solids separated in the separation means 2 are then supplied to a slurrying tank 3 as a slurrying means, where water H, acid I and carbon dioxide J are added and the slurry is formed. The slurry is formed by being stirred by a stirrer 3a attached to the tank 3, whereby the chloride F in the solidified solid is eluted in the liquid. Here, as the acid I, for example, sulfuric acid is used.

[0010] The slurry of the solids from which the chloride F has been eluted in the liquid is then sent to a dehydrating means 4 to form a dewatered cake comprising the liquid from which the chloride F has been eluted and the char E and ash G. Is separated into solid and liquid. As the dehydrating means 4, a general dehydrator such as a belt press or a vacuum filter can be used. However, in order to sufficiently separate a liquid component in which chloride F is eluted from the dehydrated cake, multiple dehydration is performed using washing water. It is desirable to be able to perform the cleaning.

Further, the dewatered cake composed of the char E and the ash G from which the liquid from which the chloride F has been eluted is separated is sent to the drying means 5 and dried. As the drying means 5, for example, an indirect heating disk type dryer is used. The dried product consisting of the char E and the ash G dried by the drying means 5 is supplied to a cement production means 6 such as a cement kiln together with the other cement main raw material K and the fuel L, and the char E and the fuel L
The ash G and the cement main raw material K are fired by the combustion energy of the above to produce the cement M.

On the other hand, the gas containing the pyrolysis gas D from which the solids have been separated in the separation means 2 is sent to a combustion furnace 7 where it is burned, and then discharged together with the exhaust gas discharged from the cement production means 6. The processing is performed by the processing means 8. Instead of burning the pyrolysis gas D in the combustion furnace 7, the pyrolysis gas D is also supplied to the cement production means 6 and burned as shown by the broken line in FIG. May be used for firing the ash content G and the cement main raw material K.

As described above, according to the method for treating waste having the above-described structure, the chloride F containing a chlorine component, a sodium component, and a potassium component in a solid separated from a product obtained by thermally decomposing the waste A is converted into a slurry. Water H is added to this solid content in
The acid I and the carbon dioxide J are added to form a slurry to elute into the liquid, and then dewatered in the dewatering means 4 to separate and remove the char E and the ash G in the solid. it can. Therefore, in the solid dewatered cake from which the chloride F has been removed in this way, even if a large amount of the dried cake by the drying means 5 is supplied to the cement production means 6, the produced cement M The quality is not impaired by the chlorine component, the sodium, and the potassium components, so that more waste A can be used as a raw material of the cement M and a fuel at the time of firing.

Further, since the chloride F containing a chlorine component is removed from the solid content containing the char E and the ash content G, the solid content is supplied to the cement production means 6 and is discharged when calcined. The exhaust gas rarely contains a chlorine component. Therefore, corrosion does not occur in the cement kiln as the cement production means 6 and the subsequent exhaust gas treatment means 8 and the like. Further, if the gas containing the pyrolysis gas D of the product generated in the pyrolysis furnace 1 is also supplied to the cement production means 6 as described above, the pyrolysis gas D is added to the combustion energy of the char E. Can also be effectively used for the production of cement.
, And more economical production of cement M can be promoted.

Further, in the processing method having the above structure, when slurrying the solid separated from the gaseous component, the acid I and the carbon dioxide J in addition to the water H are converted into the slurry 3
The pH of the slurry is controlled appropriately by controlling the amount of the acid I or carbon dioxide J added. Therefore, by adjusting the pH of the slurry liquid to the above-mentioned chloride F, the chloride F can be more reliably and efficiently eluted and removed from the slurry liquid. It is possible to more reliably prevent the quality deterioration of the cement M due to F. In addition, in the slurrying tank 3 of the processing equipment, the solid content and the water H, the acid I, and the carbon dioxide J are slurried while being stirred by the stirrer 3a. Elution can be promoted.

In this processing equipment, a common exhaust gas treatment is carried out between the exhaust gas obtained by burning the gas component of the product generated in the pyrolysis furnace 1 in the combustion furnace 7 and the exhaust gas discharged from the cement production means 6. Although the process from the thermal decomposition of the waste A to the production of the cement M can be performed in a continuous process, such as the treatment in the means 8, the thermal decomposition equipment for the waste A provided with the pyrolysis furnace 1 for thermally decomposing the waste. Often, it is located completely separately from a cement M production facility provided with a cement production means 6 such as a cement kiln, and a new cement production means 6 is provided in an existing pyrolysis facility for waste A, Alternatively, a pyrolysis furnace 1 for waste A is installed in a cement manufacturing facility.
The introduction of a new system may be uneconomical.

Therefore, in such a case, the solid content of the product generated from the pyrolysis furnace 1 in the existing waste A pyrolysis facility is also transferred to the existing cement M manufacturing facility to produce cement. If it is supplied to the means 6, the existing equipment can be used as it is, which is economical. In this case, in order to treat more solids generated from the waste A, solids from a plurality of pyrolysis facilities may be treated by one cement production facility.

In this case, the slurrying means (slurry tank 3 in the processing equipment) for slurrying the solid content, the dewatering means 4 and the drying means 5 are all composed of a pyrolysis equipment or a cement production equipment. The equipment may be provided in the equipment, or some of the former means may be provided in the pyrolysis equipment, and the remaining means in the latter part may be provided in the cement manufacturing equipment. However, in this case, the exhaust gas treatment means for treating the exhaust gas obtained by burning the pyrolysis gas and the exhaust gas treatment means for treating the exhaust gas from the cement production means 6 are separate.

[0019]

As described above, according to the present invention,
The chlorine, sodium, and potassium components contained in the solid content are eluted into the slurry by adding water, acid, and carbon dioxide to the solid content of the pyrolyzed waste product to form a slurry. Therefore, the above components are removed by dehydrating the slurry, and the slurry is dried and supplied to a cement manufacturing facility, so that the char and ash contained in the solid content are used as a part of the cement raw material and fuel. Of course, it is possible to prevent the above components from deteriorating the quality of the cement or damaging the equipment, and therefore utilize the above-mentioned solid content from a large amount of waste and to obtain a high quality cement. Can be manufactured.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a waste treatment facility according to an embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Pyrolysis furnace 2 Separation means 3 Slurry tank 4 Dehydration means 5 Drying means 6 Cement production means 7 Combustion furnace 8 Exhaust gas treatment means A Waste D Pyrolysis gas E Char F Chloride G Ash H Water I Acid J Carbon dioxide M cement

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Katsunori Nishida 2-17-15 Tsukuda, Chuo-ku, Tokyo Tsukishima Machinery Co., Ltd. F-term (reference) 4D004 AA36 AC05 BA02 BA03 CA13 CA15 CA42 CB09 CB27 CB28 CB31 CC01 CC12 4G012 KA08 4H015 AA01 AB01 BA08 BA09 BA12 BB03 BB13 CB01

Claims (1)

[Claims] 1. A solid containing char and ash is separated from a product obtained by thermally decomposing waste, and water,
A method for treating waste, comprising adding an acid and carbon dioxide gas to form a slurry, dehydrating and drying the slurry, and supplying the slurry to a cement production means.