JP4084913B2 - Method for treating desalted residue in flue gas treatment - Google Patents

Description

【００５４】
【発明の効果】
以上説明してきたように、本発明によれば、脱塩残渣をダイオキシンが分解し得る温度に加熱し、ダイオキシンを分解した後、水を加えた水溶液とし、この水溶液のうち非水溶性成分は、溶融炉に戻して燃焼溶融しスラグ化され再利用できるので、脱塩残渣を埋立処分する必要がなくなる。
【００５５】
また、ダイオキシンを分解しているので廃棄物処理装置の系内にダイオキシンが濃縮する恐れがなく、さらに、系外へ放出される恐れもない。しかも、非水溶性成分を取り除いた水溶液は、ダイオキシンを分解した後の脱塩残渣中の水溶性成分であり、この水溶液に含まれる塩化ナトリウムはＰＨ調整された後、放流するので、自然環境に与える悪影響もない。
【図面の簡単な説明】
【図１】本発明の第１の実施形態を説明するための系統図である。
【図２】本発明の第２の実施形態を説明するための系統図である。
【図３】本発明に係る加熱装置の概略図である。
【図４】図３に示した加熱装置の横断面図である。
【図５】本発明による加熱装置を採用した廃棄物処理方法または廃棄物処理方法に関する第３の実施形態を説明するための系統図である。
【符号の説明】
１ 溶融炉
３ 廃熱ボイラ
５ スラグ排出口
６ 溶融スラグ
７ スラグ冷却手段
１０、１２ 排ガス流路
１１ 第１の排ガス処理手段
１３ 第２の排ガス処理手段
１５ 重曹
１７ 供給路
２２ 脱塩残渣
２２ａ ダイオキシン類除去後の脱塩残渣
２３ 加熱装置
２３ａ 加熱部
２３ｂ 内筒
２３ｃ 定量供給装置
２３ｄ 攪拌翼
２３ｅ 空気加熱器
２３ｆ ブロワー
２３ｇ 出口フード
２３ｈ 吸引ブロワー
２３ｊ 排ガス管
２３ｋ 酸素濃度検出器
２３ｍ 加熱空気供給管
２３ｐ バルブ
２４ 分離手段
２５ 懸濁物
２６ 水溶液
２７ ＰＨ調整剤
２８ 沈殿槽
２９ 上水液
３０ 固形物
５０ 廃棄物処理装置
６３ 燃焼溶融炉
６６ スラグ排出口
６７ 水槽
７１ 第１の排ガス処理器
７２ ダスト
７３ 第２の排ガス処理器
７４ 脱塩残渣
８０ 加熱装置
８１ 固液分離装置
１００ 焼却炉
１０１ 溶融炉
１０２ 排ガス流路
１０５ スラグ排出口
１０６ 溶融スラグ
１０７ スラグ冷却手段[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for treating a desalted residue that effectively removes harmful components such as dioxins and heavy metals in a desalted residue produced by desalting a combustion exhaust gas generated by incineration or melting.
[0002]
[Prior art]
Incinerator for waste (combustible waste such as municipal waste from households and offices, waste plastic, car shredder dust, waste office equipment, electronic equipment, chemical waste, etc.) In combustion exhaust gas generated by incineration or melting (combustion melting) in a melting furnace (melting furnace, combustion melting furnace, gasification melting furnace performing melting or combustion melting) (stoker furnace, fluidized bed incinerator, etc.) Since it contains a large amount of harmful hydrogen chloride, the combustion exhaust gas is desalted to remove hydrogen chloride and then released into the atmosphere.
[0003]
In the desalting treatment, generally, a method using a calcium-based desalting agent such as slaked lime (calcium hydroxide: Ca (OH) ₂ ), quick lime (calcium oxide: CaO), and sodium bicarbonate (sodium bicarbonate or sodium bicarbonate). : NaHCO ₃ ), soda ash (anhydrous sodium carbonate: Na ₂ CO ₃ ) or any other method using a sodium-based desalting agent has been performed.
[0004]
In JP-A-2-214525, a calcium-based desalting agent is reacted with combustion exhaust gas to dissolve the generated reaction product (desalted residue), and a heavy metal sequestering agent such as a chelating agent is added to this solution. In addition, a method is disclosed in which heavy metal in the solution is separated and discharged out of the system, and calcium chloride is further crystallized from the solution from which the heavy metal is separated.
[0005]
On the other hand, Japanese Patent Application Laid-Open No. 7-504880 discloses a method of removing a heavy metal component contained in a desalted residue (reaction product) produced by reacting a sodium-based desalting agent with combustion exhaust gas. . In this invention, the desalted residue is made turbid with water to form an aqueous solution. After separating the water-insoluble component from this aqueous solution, the water-soluble component is reacted with a chelate resin, and the aqueous solution from which the heavy metal component has been removed is discharged out of the system. It is about how to do.
[0006]
[Problems to be solved by the invention]
However, in the above two inventions, heavy metals contained in the desalting residue are separated and removed, but the decomposition of dioxins (polychlorinated dibenzodioxin, polychlorinated dibenzofuran, coplanar PCB, etc.) contained in the desalted residue. No removal measures are taken.
[0007]
Of the aqueous solution of the desalted residue, the water-insoluble component (solid content) is usually subjected to landfill disposal and the like, and the dioxins contained in the desalted residue are accumulated in the soil, The aqueous solution obtained by separating the water-insoluble component (or after removing the water-insoluble component and further removing solids such as heavy metals) is discharged out of the system while containing dioxins, and is discharged into a river, lake, or ocean. Dioxins are accumulated in the area.
[0008]
In recent years, environmental pollution due to out-of-system discharge of dioxins generated at waste incineration facilities, waste melting plants, and the like has become a problem, and emission regulations for dioxins at these facilities are becoming more stringent.
[0009]
An object of the present invention is to establish a method for decomposing and removing dioxins contained in a desalted residue, so that the dioxins are not concentrated in the waste treatment system or released to the natural environment. The desalting residue is treated so as not to adversely affect it.
[0010]
[Means for Solving the Problems]
The present invention has been made to solve the conventional problems as described above, and after removing dust from combustion exhaust gas discharged from an incinerator or melting furnace, a desalting agent is added to the combustion exhaust gas. In the combustion exhaust gas treatment method in which the desalting agent is reacted with hydrogen chloride in the combustion exhaust gas and the generated desalination residue is discharged, the desalination residue is heated to a temperature at which dioxins can be decomposed, Combustion exhaust gas treatment in which the desalted residue after decomposition of the dioxins is dissolved in water to dissolve the soluble components to form an aqueous solution, the water-insoluble components in the aqueous solution are separated, and the water-insoluble components are melted A method for treating a desalted residue is provided.
[0011]
According to the method for treating a desalted residue in such a flue gas treatment, the desalting agent introduced into the flue gas reacts with hydrogen chloride in the flue gas to produce a desalted residue, which is heated. After dioxins are decomposed and removed, dissolve in water to make an aqueous solution.
[0012]
And in this aqueous solution, a water-insoluble component can be melt | dissolved (combustion melting), it can discharge | emit as molten slag, and can be reused as a building material or a paving material, and it becomes unnecessary to carry out landfill disposal. In addition, since the dioxins are decomposed and removed from the aqueous solution from which the water-insoluble components are separated, there is no possibility of causing pollution even if it is discharged.
[0013]
The desalting residue is preferably decomposed by heating to 400 to 600 ° C. The desalting residue is heated by a heating device, and the amount of air introduced into the heating device is preferably controlled so that the oxygen concentration of the exhaust gas at the outlet of the heating device is 5 to 20 vol%.
[0014]
The water-insoluble component separated from the aqueous solution is supplied to a melting furnace attached to the incinerator (or combustion furnace) or supplied to the combustion melting furnace, and is melted in a high temperature region to form molten slag. The aqueous solution from which the water-insoluble component has been separated is discharged after the pH is adjusted. Further, the water-insoluble component is separated from the aqueous solution after the pH adjustment, and the water-insoluble component is melted and discharged as molten slag.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a configuration diagram for explaining an embodiment of the present invention. As shown in FIG. 1, combustion exhaust gas Ga generated in a melting furnace 1 that performs melting or combustion melting is heat recovered by a waste heat boiler 3, and then passes through an exhaust gas flow path 10 to form a first exhaust gas treatment means (for example, Dust D such as fly ash is removed by a bag filter 11, a bag filter, an electric dust collector, a cyclone, a ceramic filter, and the like.
[0016]
After that, desalting treatment is further performed by second exhaust gas treatment means (for example, a bag filter, an electrostatic precipitator, a cyclone, a ceramic filter, a reaction device, a desalination treatment device, etc.) 13 through the exhaust gas passage 12. After the purification, the exhaust gas Gb is attracted by the induction blower 18, and the exhaust gas temperature is raised by the combustion gas of the air 19 and kerosene 20 as necessary, and the flue gas is discharged from the chimney 21 as a clean flue gas.
[0017]
The dust D is returned to the melting furnace and melted. Further, the steam generated in the waste heat boiler 3 is sent to the steam turbine of the generator 8 to generate electric power and used in the waste treatment facility or sold to an electric power company or the like.
[0018]
At this time, in the exhaust gas flow path 12, for example, sodium-based desalting agent alone or sodium bicarbonate mixed with an Si-based anti-caking agent (sodium-based desalting agent) is used for the desalting treatment by the second exhaust gas treatment means 13. ) 15 is supplied to the exhaust gas passage 12 via the supply passage 17. In the present embodiment, a description is given of dry desalting, that is, a case where a granular desalting agent is supplied to the exhaust gas passage 12.
[0019]
By the desalting treatment, the second exhaust gas treatment means 13 generates dust such as sodium chloride (NaCl), fly ash, etc. produced by reacting with hydrogen chloride (HCl) in the combustion exhaust gas, unreacted baking soda (desalting). Agent) and a desalted residue 22 composed of harmful heavy metals such as lead and cadmium.
[0020]
Then, the desalted residue 22 is introduced into the heating device 23 and heated. In the heating apparatus 23, it heats at 400 degreeC-600 degreeC which is the temperature which can decompose | disassemble dioxins in the desalination residue 22, Preferably it is 430 degreeC-500 degreeC. If the heating temperature of the desalted residue by the heating device exceeds 600 ° C, it is necessary to take measures against corrosion of the heating device by Cl content, etc. If the heating temperature is less than 400 ° C, the removal rate of dioxins decreases. There is.
[0021]
In the actual apparatus, the heating device 22 heats the desalted residue for 1 to 30 minutes, preferably 5 to 15 minutes. If it is less than 1 minute, dioxins are not sufficiently removed, and even if it exceeds 30 minutes, there is no change in the removal rate of dioxins.
[0022]
FIG. 3 is a schematic view of the heating device 23. The heating device 23 is a multi-cylinder rotary kiln composed of a heating unit 23a and a plurality of inner cylinders 23b by an electric heating method or a fuel heating method, and a quantitative supply device 23c. Thus, the desalted residue 22 supplied from the second exhaust gas treatment means 13 is introduced, heated to 400 ° C. or higher, and discharged from the outlet hood 23g. Water is added to the desalted residue 22a after the decomposition of the dioxins to produce an aqueous solution, which is sent to the filtering means 24.
[0023]
As shown in FIG. 4, each inner cylinder 23 b includes a plurality of stirring blades 23 d on the inner wall surface in order to heat the desalted residue 22 uniformly in a short time.
[0024]
Moreover, as shown in FIG. 3, the heated air heated to 20-200 degreeC with the air heater 23e is supplied to the fixed supply machine 23c. As the air heater, for example, an air heater incorporating a heater, a heat exchanger, or a fuel combustion system such as oil or gas is preferable. Further, a blower 23f is used to introduce air.
[0025]
A suction blower 23h is provided behind the outlet hood 23g provided at the outlet of the heating device 23, and the gas in the heating device 23 (such as water vapor in which water in the desalted residue 22 is evaporated) is melted in the melting furnace 1. Is forcibly discharged.
[0026]
Further, the oxygen concentration detector 23k provided in the exhaust gas pipe 23j between the outlet hood 23g and the suction blower 23h controls the valve 23p of the heated air supply pipe 23m, and the oxygen concentration of the exhaust gas at the outlet of the heating device 23 is 5 to 20 vol. %, The amount of air introduced into the heating device 23 is controlled.
[0027]
As shown in FIG. 1, when water is added to the desalted residue 22a after decomposition of dioxins to produce an aqueous solution, the water-soluble component in the desalted residue 22a is soluble in water, but the water-insoluble component is an aqueous solution. It exists as a suspension in. The suspension is composed of sodium chloride (NaCl) generated by reaction with hydrogen chloride (HCl) in combustion exhaust gas, dust such as fly ash, unreacted desalting agent, heavy metal, and the like. At this time, it is preferable to introduce a heavy metal removing agent such as a chelate resin into the aqueous solution to separate heavy metals such as lead, cadmium and iron.
[0028]
This aqueous solution is introduced into a separation means 24 such as a centrifugal separator, a belt press dehydrator, a filter press dehydrator, a vacuum dehydrator, a membrane separator, etc., thereby suspending a suspension that is a water-insoluble component. Object 25 is separated from the aqueous solution.
[0029]
The suspension 25 separated by the separation means 24 is returned to the melting furnace 1, and is 1,200 ° C. to 1,500 ° C., preferably 1,250 to 1,400 ° C. in the melting furnace 1. Melting (or combustion melting) is performed at a high temperature around 1,300 ° C., and the suspension 25 becomes molten slag.
[0030]
The slag 6 discharged from the slag discharge port 5 at the lower part of the melting furnace 1 falls into slag cooling means 7 such as a water tank or a water spray device (not shown), rapidly cooled and solidified to become granulated slag. The granulated slag is formed in a granular shape or is blocked into a predetermined shape by a device (not shown) and can be reused as a building material, a paving material, or the like.
[0031]
Slag is an amorphous substance composed of silicon oxide (SiO ₂ ), calcium oxide (CaO), alumina (Al ₂ O ₃ ), etc. Therefore, harmful heavy metals (lead, cadmium, etc.) contained in slag are There is almost no fear of elution, and a stable state can be maintained for a long time. Therefore, there is no adverse effect on the natural environment even if the crushed slag is reused as a building material, paving material or the like.
[0032]
The aqueous solution 26 from which the suspension 25 has been removed by the separation means 24 contains a water-soluble component of the desalted residue 22a, and a PH adjusting agent (for example, hydrochloric acid, sulfuric acid, etc.) 27 is added to the aqueous solution 26. Then, the PH of a trace amount of heavy metal contained in the water-soluble component of the desalted residue 22 a contained in the aqueous solution 26 is adjusted and stirred and mixed in the precipitation tank 28.
[0033]
At this time, solids such as heavy metals in the aqueous solution 26 are precipitated and separated from the aqueous solution 26. Since the clean water 29 in the settling tank 28 is separated from the solid 30 and discharged as a harmless sodium chloride aqueous solution, there is no risk of problems such as environmental pollution. In addition, you may collect | recover upper water liquid (sodium chloride aqueous solution), and it may recycle | recycle as sodium chloride in the sodium chloride reproduction | regeneration processing facility outside a system.
[0034]
On the other hand, the solid material 30 such as heavy metal separated from the aqueous solution by adjusting the pH is extracted from the lower part of the precipitation tank 28 and supplied to the combustion melting furnace 1 to be melted into the molten slag 6 and from the slag discharge port 5 at the lower part of the combustion melting furnace 1. It is discharged and falls to the slag cooling means 7, rapidly cooled and solidified to become a granulated slag.
[0035]
Thus, in this embodiment, after dioxins contained in the desalting residue are decomposed with a heating device and water is added to form an aqueous solution, water-insoluble components and solids in this aqueous solution are slag in a combustion melting furnace. The aqueous solution from which the water-insoluble components are separated and reused as a harmless substance is also useful from the viewpoint of nature protection because it is discharged after adjusting the pH of the sodium chloride contained therein.
[0036]
In addition, although the said embodiment demonstrated the case of a sodium-type desalting agent, even if it uses a calcium-type desalting agent, it cannot be overemphasized that the effect similar to the said embodiment is acquired.
[0037]
Next, a second embodiment of the present invention will be described with reference to the drawings.
FIG. 2 is a configuration diagram in which a melting furnace 101 that performs melting or combustion melting is attached to a waste treatment facility equipped with an existing or new incinerator 100 such as a stalker furnace or a fluidized bed waste incinerator. is there. In FIG. 2, the same reference numerals as those in FIG. 1 comprise the same devices as those in FIG. 1, and have the same functions and effects as those in FIG.
[0038]
The combustion exhaust gas Gk discharged from the incinerator 100 is subjected to the desalination treatment by the second exhaust gas treatment means 13 after the dust DA is removed by the first exhaust gas treatment means 11 through the exhaust gas passage 102, The purified exhaust gas Gm is discharged from the chimney 21.
[0039]
The dust DA is returned to the melting furnace 101 and melted. Then, the molten slag 106 is discharged from the slag discharge port 105 at the bottom of the melting furnace 101, falls to the slag cooling means 107, and becomes granulated slag. Further, similarly to the first embodiment, the suspension 25 and the solid 30 are also sent to the melting furnace 101 and melted.
[0040]
Thereby, even in a waste treatment facility equipped with an existing incinerator such as a stalker furnace, a fluidized bed incinerator, a multi-stage sludge incinerator, dioxins contained in the desalted residue can be decomposed and removed by the heating device. . Furthermore, the non-water-soluble components in the aqueous solution in which the desalted residue is dissolved in water are returned to the melting furnace to become slag, which can be used as building materials and paving materials, and the aqueous solution from which the water-insoluble components are separated is rendered harmless and released. So there is no risk of adverse effects on the environment.
[0041]
Next, a third embodiment of the present invention will be described with reference to the drawings.
FIG. 5 is a system diagram of the waste treatment apparatus 50. In the waste treatment apparatus 50, the crusher 52 is a crusher such as a biaxial shear type or a triaxial shear type disposed in the receiving yard, and the waste a such as municipal waste is crushed by the first conveyor 51. 52, where it is crushed to, for example, 150 mm square or less.
[0042]
The crushed waste a is introduced by the second conveyor 53 and supplied to the pyrolysis reactor 55 through the screw feeder 54. For example, a horizontal rotary drum is used for the thermal decomposition reactor 55, and the inside thereof is maintained in a low oxygen atmosphere by a seal mechanism (not shown) and is heated by a heat exchanger 68 disposed on the downstream side of the combustion melting furnace 63. been heated air is supplied from the line L _1.
[0043]
The waste a supplied into the pyrolysis reactor 55 by the heated air is heated to 300 to 600 ° C., preferably 400 to 550 ° C., and in this embodiment to about 450 ° C. Thus, this waste a is thermally decomposed, the carbonization gas G _1, primarily to produce a pyrolysis residue b nonvolatile. The pyrolysis gas G ₁ and pyrolysis residue b produced in the pyrolysis reactor 55 are separated by a discharge device 56, and the pyrolysis gas G ₁ is combusted and melted through a line L ₂ that is a pyrolysis gas pipe. It is supplied to the burner 62 of the furnace 63.
[0044]
The pyrolysis residue b is mainly composed of combustible matter, ash, metal, rubble, etc., but is discharged at a relatively high temperature of about 450 ° C., and after being cooled to about 80 ° C. by the cooling device 57, It is led to a pyrolysis residue separator 58 where it is separated into a combustible component C and an incombustible component D. As the separation device 58, for example, a known sorter of a magnetic separation type, a centrifugal type or a wind sorting type is used. The combustible component c from which the non-combustible component d is separated and removed by the separation device 58 is supplied to the pulverizer 60. The pulverizer 60 is suitably a roll type, a tube mill type, a rod mill type, a ball mill type or the like, and is appropriately selected depending on the properties of the waste to be treated.
[0045]
The combustible component c in this grinder 60 is preferably ground to all 1mm or less, the ground combustible component c is supplied to the burner 62 of the burning melting furnace 63 via line L _3. On the other hand, the combustion air supplied from the line L ₄ by the blower 61, and the pyrolysis gas G ₁ and the combustion component c is burned in a high temperature range of about 1300 ° C. in the combustion melting furnace 63, the combustion of the combustion The ash generated from the component c melts to produce a molten slag f.
[0046]
The incombustible component d may be temporarily stored in a hopper 59 such as a container, then crushed to about 1 mm by a pulverizer 64, and supplied to the lower portion of the combustion melting furnace 63 via a heater 65. In addition, the object to be processed melted in the combustion melting furnace 63 is melted (combustion melted) to form molten slag f, which falls from the slag discharge port 66 into the water tank 67 and becomes granulated slag.
[0047]
The combustion exhaust gas G ₂ generated in the combustion melting furnace 63 of such a waste treatment apparatus is recovered by the heat exchanger 68 and further recovered by the waste heat boiler 69 from the line L _{6 as} necessary. after the dust collecting dust 72 by the first exhaust gas treatment device 71, it is desalted second exhaust gas treatment unit 73, after discharging the Datsushiozan渣74, low-temperature clean exhaust gas G _3, and the attraction blower After passing through 75, it is emitted from the chimney 76 to the atmosphere. Note that the steam generated in the waste heat boiler 69 is sent to the steam turbine of the power generator 70 to generate power and used in the waste treatment apparatus 50 or sold.
[0048]
In this embodiment, at the front stage of the second exhaust gas treatment unit 73, as desalting agents to remove hydrogen chloride in the exhaust gas, the sodium-based dechlorinating agent 78 was ground is turned on, the hydrogen chloride in the combustion exhaust gas G ₂ And is discharged from the second exhaust gas treatment device 73 as a desalting residue 74. The desalted residue 74 is introduced into a heating device 80 where it is heated to decompose dioxins.
[0049]
Next, water is added to the desalted residue 74 from which the dioxins are decomposed, and the aqueous solution is separated into solid and liquid such as a centrifugal separator, a belt press dehydrator, a filter press dehydrator, a vacuum dehydrator, a membrane separator, and the like. Introduced into the device 81. This is separated from the aqueous solution is water-insoluble components in Datsushiozan渣74, the water-insoluble component separated is returned to the burner 62 of the melting furnace 63 through a line L _10, burned in the melting furnace 63・ Melted into slag. The aqueous solution from which the water-insoluble component has been removed by the solid-liquid separator 81 is discharged after the pH adjustment.
[0050]
<Experimental example 1>
In order to understand the reaction mechanism of the decomposition of dioxins in the desalted residue, the sample of the desalted residue in the melting furnace is packed in a flow-through fixed bed small reactor (1-3 cc) with a mass spectrometric detector to decompose the dioxins. As a substance simulating the above, O-chlorophenol (hereinafter referred to as CP) was pulse-injected and evaluated by its decomposition behavior.
[0051]
To understand the influence of oxygen concentration, the reaction temperature is 450 ° C, the heating time is 1 minute, and the oxygen concentration is 8 levels of 0 vol%, 3 vol%, 5 vol%, 8 vol%, 12 vol%, 15 vol%, 20 vol%, 25 vol%. The ratio of oxidative decomposition during the organochlorine compound decomposition reaction was determined.
[0052]
The results are shown in “Table 1”. From this “Table 1”, it was found that when the oxygen concentration was 8 to 15 vol%, the oxidative decomposition during the organic chlorine compound decomposition reaction was 90% or more. Moreover, when the oxygen concentration was 3 vol% or less, the oxidative decomposition rate decreased, and even when it exceeded 20 vol%, the oxidative decomposition rate did not change significantly. The ratio by oxidative decomposition was determined from the balance of the amount of unreacted CP and the amounts of CO ₂ and H ₂ O with CP as an index substance.
[0053]
[Table 1]

[0054]
【The invention's effect】
As described above, according to the present invention, the desalted residue is heated to a temperature at which dioxins can be decomposed, and after dioxins are decomposed, an aqueous solution is obtained by adding water. Since it is returned to the melting furnace and burned, melted, slagged and reused, there is no need to landfill the desalted residue.
[0055]
In addition, since dioxins are decomposed, there is no risk of dioxins concentrating in the system of the waste treatment apparatus, and there is no risk of being released outside the system. Moreover, the aqueous solution from which the water-insoluble components have been removed is the water-soluble component in the desalted residue after decomposing dioxins, and the sodium chloride contained in this aqueous solution is discharged after the pH has been adjusted. There is no adverse effect.
[Brief description of the drawings]
FIG. 1 is a system diagram for explaining a first embodiment of the present invention;
FIG. 2 is a system diagram for explaining a second embodiment of the present invention.
FIG. 3 is a schematic view of a heating apparatus according to the present invention.
4 is a cross-sectional view of the heating apparatus shown in FIG.
FIG. 5 is a system diagram for explaining a third embodiment relating to a waste treatment method or a waste treatment method employing a heating device according to the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Melting furnace 3 Waste heat boiler 5 Slag discharge port 6 Molten slag 7 Slag cooling means 10, 12 Exhaust gas flow path 11 First exhaust gas treatment means 13 Second exhaust gas treatment means 15 Baking soda 17 Supply path 22 Desalination residue 22a Dioxins Desalination residue 23 after removal Heating device 23a Heating section 23b Inner cylinder 23c Constant supply device 23d Stirring blade 23e Air heater 23f Blower 23g Outlet hood 23h Suction blower 23j Exhaust gas pipe 23k Oxygen concentration detector 23m Heated air supply pipe 23p Valve 24 Separation means 25 Suspension 26 Aqueous solution 27 PH adjuster 28 Precipitation tank 29 Upper water liquid 30 Solid 50 Waste treatment device 63 Combustion melting furnace 66 Slag outlet 67 Water tank 71 First exhaust gas treatment device 72 Dust 73 Second Exhaust gas treatment device 74 Desalination residue 80 Heating device 81 Solid-liquid separation device 100 Incinerator 101 Melting Furnace 102 exhaust gas line 105 slag discharge port 106 molten slag 107 slag cooling means

Claims (6)

After dust is removed from the combustion exhaust gas discharged from the incinerator or melting furnace, a desalting agent is added to the combustion exhaust gas, and the desalting residue generated by reacting the desalting agent with hydrogen chloride in the combustion exhaust gas is discharged. In the combustion exhaust gas treatment method, the demineralized residue is heated to a temperature at which dioxins can be decomposed, the demineralized residue obtained by decomposing dioxins is dissolved in water, and soluble components are eluted to form an aqueous solution. A method for treating a desalted residue in combustion exhaust gas treatment, comprising separating a water-insoluble component in the aqueous solution and melting the water-insoluble component. The method for treating a desalted residue in a combustion exhaust gas treatment according to claim 1, wherein the desalted residue is heated to a temperature selected from a range of 400 to 600 ° C to decompose dioxins. The combustion according to claim 1 or 2, wherein the amount of air introduced into the heating device is controlled such that the oxygen concentration of the exhaust gas at the outlet of the heating device for heating the desalting residue is 5 to 20 vol%. A method for treating desalted residues in exhaust gas treatment. The method for treating a desalted residue in a combustion exhaust gas treatment according to claim 1, wherein the water-insoluble component is supplied to a melting furnace attached to an incinerator and melted and discharged as molten slag. The method for treating a desalted residue in combustion exhaust gas treatment according to claim 1, wherein the aqueous solution from which the water-insoluble component has been separated is adjusted to pH and then released to the outside of the system. The method for treating a desalted residue in combustion exhaust gas treatment according to claim 1, wherein after the pH of the aqueous solution is adjusted, the water-insoluble component separated from the aqueous solution is melted.

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