JP2003194322A - Method for melting treatment of burned ash - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for melting treatment of burned ash which melt-treats the burned ash without melting the refractory material of a melting furnace even when fly ash with high basicity is added to main ash when the main ash produced in an incineration furnace is melt-treated in the melting furnace. <P>SOLUTION: When the main ash as burnt residue produced by an incineration treatment of waste in the incineration furnace is melt-treated in the melting furnace 10, fly ash discharged together with flue gas is added to the main ash and molten in the incineration treatment, and basicity adjusting material is added to the main ash beforehand to adjust the basicity of the entire part to a set basicity. Then the melting treatment is performed in the melting furnace 10. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of melting main ash as a cinder generated from an incinerator, and more particularly to a method of melting fly ash discharged together with exhaust gas during incineration. .

[0002]

2. Description of the Related Art Waste such as municipal waste is transported to an incineration plant and incinerated in an incinerator 200 as shown in FIG. The cinder produced by incineration in the incinerator 200 is called main ash, and has been disposed of as it is at a disposal site.

However, in recent years, it has been difficult to secure a disposal site, so that the main ash is melted in a melting furnace to be slag, which is utilized as a roadbed material or the like. There is. Usually, the basicity (Ca
O / SiO ₂ ) is about 0.2 to 0.5.

By the way, when incinerating waste in the incinerator 200, exhaust gas is also generated due to combustion. This exhaust gas contains a large amount of dust, and as shown in FIG. 3, the dust in the exhaust gas from the incinerator 200 is collected by the bag filter 202 and separated. . This collected dust is called fly ash.

By the way, the exhaust gas generated in the incinerator 200 contains acid gas such as HCl (hydrogen chloride) and SO _X (sulfur oxide) and NO _X gas, and therefore, there is a bag filter when treating the exhaust gas. Slaked lime (Ca (OH)
₂ ) Particles such as ₂ ) are blown into the duct or flue to neutralize the acid gas, and then the exhaust gas is denitrated (denitrified) by the denitration device 204.
NO _X ) and release it to the atmosphere.

Therefore, the fly ash collected by the bag filter 202 is disposed of after a stabilizing treatment is added to the fly ash to stabilize it. That is, in the past, only the main ash from the incinerator 200 was melted and the fly ash was stabilized by adding an expensive stabilizer. On the other hand, in recent years, when the main ash is melt-processed, fly ash is added to the main ash to melt-process them together.

[0007]

However, if not only the main ash but also the fly ash is added to the main ash for melting treatment, the following difficult problems occur. As described above, the basicity of the main ash is as low as 0.2 to 0.5. Therefore, in the case of melting treatment of only the main ash, the problem of melting loss of the refractory material of the melting furnace does not occur, In the case of adding, since the basicity is high, the refractory material of the melting furnace is melted and melted when it is melted as it is, and the durable life thereof is significantly impaired.

The high basicity of fly ash is mainly attributed to particles such as slaked lime added to neutralize the acid gas in the exhaust gas generated during incineration. Particles such as slaked lime are added in excess of the theoretical amount required to treat acidic gas, so unreacted particles such as slaked lime remain in fly ash, which increases the basicity of fly ash. It will end up.

Usually, the basicity of this fly ash varies widely in the range of 0.7 to 4. The main reason for this is that the type and amount of chemicals used for desulfurization and desalination are different in each incineration plant, and the type of equipment for desulfurization or desalination is different.

[0010]

[Means for Solving the Problems] The melting treatment method for incinerated ash according to the present invention has been devised to solve such problems. Therefore, in claim 1, when the main ash as the cinder generated by the incineration process of the waste in the incinerator is melt-processed in the melting furnace, it is discharged along with the exhaust gas in the incineration process. The fly ash is added to the main ash so as to be melted, and the basicity of the whole is adjusted to a set basicity by adding a basicity adjusting material in advance during the melting, and then the melting treatment is performed in the melting furnace. It is characterized by doing.

According to a second aspect of the present invention, the basicity of the fly ash melt-processed together with the main ash in the first aspect is measured in advance, and the necessary basicity adjusting material is obtained from the measured basicity and the treated amount. It is characterized in that the input amount is calculated and input.

A third aspect of the present invention is characterized in that, in any one of the first and second aspects, the basicity is set to 1 or less.

[0013]

As described above, according to the present invention, fly ash is added to the main ash to be melted, and at that time, a large amount of SiO ₂ such as a basicity adjusting material such as river sand and waste glass is contained. A basicity adjusting material is added to adjust the overall basicity to a set basicity, and the main ash and fly ash are melt-processed thereon. Despite the fact that ash is added to the main ash and melt-processed, they can be melt-processed under a set basicity, which can effectively prevent melting damage of the refractory material in the melting furnace and improve its durability. It is possible to prevent the life from being shortened by fly ash treatment. Furthermore, since the fly ash can be melt-processed together with the main ash, the cost for the fly ash treatment can be reduced.

If only one kind of fly ash should be added, it is considered that the basicity of the fly ash hardly changes. Therefore, once the basicity of the fly ash has been obtained, it is not necessary to adjust the amount of the basicity adjusting material added each time the fly ash is melted.

However, when fly ash generated from a plurality of different incinerators is collected and melt-processed, or when the amount of fly ash from each incinerator differs from melt-process to fly-ash, the melt-processed fly-ash is mixed. The basicity of the ash is not constant, and the value varies widely.

Here, the melt processing method of claim 2 is
The basicity of the fly ash is measured in advance, and the required amount of basicity adjusting material is calculated based on the measured basicity and the amount to be processed. Even if the basicity of the fly ash to be fluctuated greatly, that is, by collecting the fly ash generated from different incinerators,
Even when melt processing is performed collectively, or even when the amount of fly ash mixed from each incineration plant during melt processing changes, the main ash and fly ash are mixed under stable basicity without any problems. It is possible to melt-process the ash. Here, the set basicity can be set to 1 or less (claim 3).

[0017]

Embodiments of the present invention will now be described in detail with reference to the drawings. In FIG. 1, 10 is an arc type melting furnace, and the melting ash 10 melts the main ash and fly ash generated in the incinerator. The melt is then granulated and slagged. Reference numeral 12 is a main electrode in the arc type melting furnace 10, and 14 is an auxiliary electrode.

Reference numeral 16 is a main ash storage tank for storing the main ash (fine grain ash) generated in the incinerator, and the main ash generated in the incinerator is stored here and cut into a fixed amount and charged into the melting furnace. It is charged into the melting furnace 10 by the conveyor 18. 20
Is a fly ash storage tank for storing fly ash generated at the incinerator (own factory) in which the incinerator and the melting furnace 10 are installed.
Is a receiving fly ash storage tank for collecting and storing fly ash generated in a plurality of other incinerators where the melting furnace 10 is not installed.

The fly ash stored in these fly ash storage tanks 20 and 22 is once put into a fly ash charging hopper 26 by a conveyor 24 and then dropped from the fly ash charging hopper 26 to a melting furnace charging conveyor 18. It is charged into the melting furnace 10 by being conveyed by the melting furnace charging conveyor 18.

28 is a basicity adjusting material cutting tank containing SiO ₂ such as river sand and waste glass. The basicity adjusting material stored in this tank is cut out by a predetermined amount and the basicity adjusting material feeding hopper 32 is fed by the conveyor 30. Can be put in. Then, it is dropped from the basicity adjusting material charging hopper 32 to the melting furnace charging conveyor 18 and charged into the melting furnace 10.

FIG. 2 is a block diagram showing the flow until the main ash and the fly ash are conveyed to the melting furnace 10.
Reference numerals 36 and 38 denote receiving fly ash storage tanks for respectively storing fly ash carried from other incinerators in which the melting furnace 10 is not installed. Here the receiving fly ash storage tanks 34, 36, 3
8 stores only the same type of fly ash from the same incinerator.

The fly ash in the received fly ash storage tanks 34, 36 and 38, which respectively store only the same type of fly ash, is once supplied to the received fly ash storage tank 22 and stored therein. The fly ash in the received fly ash storage tanks 34, 36, 38 is stored in the received fly ash storage tank 22 in a mixed state at a predetermined ratio.

As is clear from the above description, the received fly ash storage tank 22 receives fly ash from another incineration plant in which the melting furnace 10 is not installed and stores it in a mixed state. Fly ash in the ash storage tank 22 and the melting furnace 1
The fly ash in the fly ash storage tank 20 generated in the own factory where No. 0 is installed is supplied to the melting furnace 10 through the fly ash charging hopper 26 and the melting furnace charging conveyor 18 as described above.
It should be noted that the main ash in the main ash storage tank 16 and the basicity adjusting material in the basicity adjusting material input hopper 32 are combined and the melting furnace charging conveyor 18
The point of being charged into the melting furnace 10 is as described above.

In this example, the receiving fly ash storage tanks 34, 36, 38
The basicity of the fly ash (a), (b) and (c) stored in (3) is sampled at the downstream portion of each of the receiving fly ash storage tanks (34, 36, 38) (sample names S4, S5, S6) and the melting furnace 10 A simple analyzer (Fluorescent X installed in a factory
Measure the basicity of each fly ash (a), (b), (c) with a line analyzer, etc.). Specifically, the CaO content and the SiO ₂ content of each fly ash (a), (b), and (c) are measured. The time required at that time is a short time of about 30 minutes.

At the same time, the main ash, the fly ash of the own factory, and the basicity of the basicity adjusting material are sampled at the downstream of the main ash storage tank 16, the fly ash storage tank 20, and the basicity adjusting material feeding hopper 32. Then (named sample names S1, S3, S7),
Similarly, measure with a simple analyzer.

Table 1 shows the amount of CaO and the amount of SiO ₂ in the samples S1 to S7 measured as described above, respectively.
1 to CS7 and SS1 to SS7.

[0027]

[Table 1]

Here, the respective processing amounts of fly ash a, b, and c are as follows, and fly ash a: processed amount FA4 fly ash b: processed amount FA5 fly ash c: processed amount FA6 Assuming that the amount of ash treated and the amount of fly ash treated by the plant are as follows: main ash: treated amount BA1, treated fly ash of the plant: treated amount FA3, the basicity of the treated ash is calculated as follows. be able to.

[0029]

[Equation 1]

[Equation 2]

[Equation 3]

Furthermore, when the amount of the basicity adjusting material added is X as follows, the amount of the basicity adjusting material added to set the basicity of the whole incinerated ash, which is a combination of main ash and fly ash, to 1 X is derived by the following formula.

[0031]

[Equation 4]

That is, the basicity of the whole incinerated ash can be set to 1 by adding the amount of the basicity adjusting material thus obtained to the main ash and the fly ash. In this example, the basicity is adjusted to 1 in this way, and then the main ash and the fly ash are charged into the melting furnace 10 to perform the melting process.

As shown in FIG. 2, fly ash a, b,
A sample is taken at the downstream portion of the receiving fly ash storage tank 22 in which c is stored in a mixed state (sample name S2), the basicity of the mixed fly ash is measured, and the treated amount is FA4 + FA5 + FA6.
It is also possible to calculate as the processing amount of the entire fly ash a, b, and c.

Alternatively, the basicity of the mixed fly ash is measured at P ₁ before the fly ash a, b, and c enter the receiving fly ash storage tank 22, and the basicity is calculated based on this. good. Further, the basicity may be calculated at each of the downstream portion and the upstream portion of the received fly ash storage tank 22, and either one may be used for checking.

It is to be noted that although the description has been made assuming that all the fly ash a, b, and c are mixed here, the respective processing amounts FA
If any one or two of 4, FA5 and FA6 is 0,
That is, even when one or two of fly ash a, b, and c are not mixed, the basicity is calculated according to the present example, and the processing method of the present invention is of course applicable to the case where the input amount of the basicity adjusting material is determined. include.

On the contrary, in the above-mentioned embodiment, 3 other than the own factory is used.
Although the description has been given on the assumption that various types of fly ash are received and melt-processed, this is merely an example, and the present invention is of course applicable to the case where more than one fly ash is received and melt-processed. However, in some cases, the present invention can be applied when only the fly ash of other incinerators is melt-processed without including the fly ash of the own factory.

According to the melting treatment method for incinerated ash of the present embodiment as described above, although the fly ash having a high basicity is added to the main ash and melted, they are melt-treated at a basicity of 1 or less. As a result, melting loss of the refractory material in the melting treatment furnace 10 can be effectively prevented, and its durable life can be prevented from being shortened by fly ash treatment.

Further, since the fly ash can be melt-processed together with the main ash, the cost for the fly ash treatment can be reduced. Further, according to the present invention, not only in the case where a single kind of fly ash is added to the main ash and melt-processed, it is possible to collectively melt-process a plurality of types of fly ash having different basicities. Even in that case, the main ash and the fly ash can be melt-processed under a stable basicity without any trouble, regardless of the change in the basicity of the fly ash.

Although the embodiment of the present invention has been described in detail above, this is merely an example. For example, in the present invention, it is also possible to adjust the basicity of the whole incinerated ash obtained by adding fly ash to the main ash to an arbitrary set value of 1 or less. It can be implemented in a modified form.

[Brief description of drawings]

FIG. 1 is an explanatory view showing an equipment using a method according to an embodiment of the present invention.

FIG. 2 is a block diagram systematically showing a flow until the main ash and the fly ash in FIG. 1 are conveyed to a melting furnace.

FIG. 3 is an explanatory diagram for explaining the background of the present invention.

[Explanation of symbols]

10 melting furnace 16 Main ash storage tank 20 Fly ash storage tank 22 Receiving fly ash storage tank 26 Fly ash input hopper 32 Basicity adjusting material feeding hopper

   ─────────────────────────────────────────────────── ─── Continued front page    F term (reference) 3K061 NB02 NB06                 3K062 AA18 AB03 AC03 BA01 BB05                       CA00 CB01 DA40 DB02                 4D004 AA36 AA37 AC04 BA02 CA29                       CA34 CB04 CC11 DA01 DA02                       DA10

Claims (3)

[Claims] 1. When the main ash as a cinder that is generated by the incineration of waste in an incinerator is melt-treated in a melting furnace, the fly ash discharged along with the exhaust gas during the incineration is the main ash. In addition to the ash, so as not to melt, and after adjusting the basicity of the entire basicity by adding a basicity adjusting material in advance at the time of the melting, the melting process in the melting furnace, Method for melting incinerated ash. 2. The basicity of fly ash that is melt-processed together with the main ash according to claim 1, and the required amount of the basicity adjusting material is determined from the measured basicity and the treated amount. A method for melting and treating incinerated ash, characterized in that 3. The melting treatment method for incineration ash according to claim 1, wherein the basicity is set to 1 or less.