JP3841639B2 - Flue structure of ash melting furnace - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a flue structure of an ash melting furnace for leading exhaust gas from an ash melting furnace attached to a waste treatment facility to the downstream side.
[0002]
[Prior art]
Conventionally, a method for melting incinerated ash discharged from an incinerator using an ash melting furnace has been performed. Since it is difficult to secure a final disposal site, the main purpose is to reduce the volume by melting and solidifying the incinerated ash. In recent years, this melting treatment method is capable of decomposing dioxins contained in the incineration ash etc. by melting and solidifying the incineration ash etc. discharged from the incinerator at a high temperature, and heavy metals contained in the incineration ash etc. It is attracting attention from the viewpoint of detoxification such as prevention of elution.
[0003]
On the other hand, in a waste treatment facility, incineration ash (main ash) discharged from an incinerator and incineration of municipal waste, etc., and fly ash collected by a dust collector or the like arranged downstream of the incinerator Will occur. Although these incineration residues contain dioxins, the concentration of dioxins in the main ash is relatively low, but due to factors such as generation during combustion and resynthesis during cooling, fly ash contains Dioxins are contained in high concentration. In addition, fly ash contains salt and heavy metals volatilized in the incinerator, which is cooled together with the exhaust gas discharged from the incinerator and condensed during the cooling process. A large amount of salts and heavy metals are included.
[0004]
Therefore, from the viewpoint of detoxification described above, many processing methods are used in which main ash and fly ash generated in incineration are mixed and both are melted and solidified by an ash melting furnace. In this treatment method, the main ash / fly ash is heated to 1250 to 1450 ° C. or higher by using fuel combustion heat or electric energy to slag the main ash / fly ash, and the slag is rapidly cooled. Or it is the method of cooling slowly and solidifying. In this processing method, the exhaust gas generated in the ash melting furnace is discharged downstream through the ash melting furnace flue connected to the ash melting furnace.
[0005]
[Problems to be solved by the invention]
However, according to the treatment method described above, the fly ash containing a large amount of salts and heavy metals and the main ash are mixed and melted, so that the vaporized salts and heavy metals are contained in the exhaust gas generated in the ash melting furnace. It will contain a lot of food. For this reason, for example, the temperature decreases as the exhaust gas of about 1300 ° C. exiting the ash melting furnace flows downstream in the ash melting furnace flue connected to the ash melting furnace, and the temperature decreases to about 950 ° C., the boiling point of the NaCl compound. When this occurs, salts and the like mainly composed of NaCl compounds contained in the exhaust gas liquefy. This liquefied salt or the like (hereinafter simply referred to as “liquefied product”) flows downstream along the flow of exhaust gas from the ash melting furnace and is further connected to the downstream side of the ash melting furnace flue. It flows into the dust discharge hopper, further cools down in the dust discharge hopper, and solidifies at the freezing point of the liquefied product. For this reason, the hopper part formed in the lower part of the dust discharge hopper is clogged, and in order to remove the solid matter clogged in the hopper part, a very severe removal work using a rock drill is required. There is a point.
[0006]
In addition, the phenomenon in which the salt in the exhaust gas liquefies in the ash melting furnace flue is caused especially after the start-up of the operation of the ash melting furnace until the normal operation. Thereafter, the temperature in the ash melting furnace flue rises due to the influence of radiant heat from the refractory in the flue accompanying the operation of the ash melting furnace, so that this liquefaction phenomenon is not caused.
[0007]
The present invention has been made in view of such problems, and can prevent the liquefied material generated in the ash melting furnace flue from flowing out to equipment connected to the ash melting furnace flue, thereby An object of the present invention is to provide an ash melting furnace flue capable of avoiding the solidification of the liquefied product and clogging in the equipment.
[0008]
[Means for solving the problems and actions / effects]
In order to achieve the above object, the flue structure of the ash melting furnace according to the first invention is:
An ash melting furnace flue structure connected to and connected to an ash melting furnace to lead the exhaust gas from the ash melting furnace to the downstream side, and the liquefied product in the exhaust gas in the ash melting furnace flue It is characterized in that a staying means for staying in is provided.
[0009]
According to the present invention, the liquefied material in the exhaust gas is retained in the ash melting furnace flue by the retaining means provided in the ash melting furnace flue, and the temperature due to radiant heat from the refractory in the ash melting furnace flue It is gasified as it rises and is sent downstream along with the exhaust gas discharged from the ash melting furnace. Therefore, it is possible to prevent the liquefied material from flowing out to facilities connected to the ash melting furnace flue, and avoid problems such as solidification of the liquefied material and clogging of the facilities. Can do.
[0010]
1st invention WHEREIN: The said retention | holding means is provided with the 1st weir provided in the upstream end part of the said ash melting furnace flue, and the 2nd weir provided in the downstream end part of the said ash melting furnace flue (Second invention). In this way, since the liquefied material in the exhaust gas can be retained in the portion partitioned by the first weir and the second weir, the function and effect of the first invention can be obtained with a simple structure. Can do.
[0011]
Further, in the first invention, the staying means is arranged so as to incline the ash melting furnace flue toward the downstream end side so as to rise upward, and a weir is provided at the upstream end of the ash melting furnace flue. It can also be set as the provided structure (3rd invention). Even with such a configuration, the same operation and effect as the second invention can be obtained.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Next, specific embodiments of the flue structure of the ash melting furnace according to the present invention will be described with reference to the drawings.
[0013]
FIG. 1 shows a configuration diagram of a main part of an exhaust gas treatment system for an ash melting furnace according to an embodiment of the present invention. 2A shows an enlarged sectional view taken along the line XX in FIG. 1, and FIG. 2B shows an enlarged sectional view taken along the line YY in FIG.
[0014]
In the exhaust gas treatment system of the present embodiment, the ash melting furnace 1 includes a melting furnace main body 2, main ash, fly ash, and the like that are attached to the melting furnace main body 2 and generated in a waste incinerator (not shown) in a previous process. Ash supply for supplying an appropriate amount of the molten material stored in the incinerated ash charging chute 3 into which the molten material is charged and the ash storage part 4 formed in the lower part of the incinerated ash charging chute 3 into the melting furnace body 2 A pusher 5 is provided. A burner 6 is provided on the ceiling portion of the melting furnace main body 2, and the temperature inside the furnace is raised to 1350 to 1450 ° C. by the burner 6 so that the material to be melted is melted from the surface. In this way, the material to be melted supplied into the melting furnace main body 2 is sequentially made into molten slag. Further, a slag tap 7 having a cylindrical structure is extended below the melting furnace body 2 so as to communicate with the interior of the melting furnace body 2, and the tank is filled with cooling water at the lower part of the slag tap 7. The slag water cooling tank 8 is connected. In this way, the material to be melted (molten slag) melted in the melting furnace main body 2 is dropped into the slag water cooling tank 8 and crushed. In the slag water cooling tank 8, a slag carry-out conveyor 9 for carrying out the molten and crushed molten slag is provided.
[0015]
An ash melting furnace flue 20 is connected to the slag tap 7 so as to communicate with the slag tap 7 and to have a horizontal conduction direction. This ash melting furnace flue 20 is a cylindrical flue having a double laminated structure made of fireproof and heat insulating castable. The ash melting furnace flue 20 has an ash melting furnace flue at the upstream end of the exhaust gas flow (in the direction of arrow F in FIG. 1) from the melting furnace main body 2 and the downstream end of the exhaust gas flow. A first weir 21 and a second weir 22 are arranged along the inner peripheral wall of the inner lower portion of the 20. In this way, a retention portion 25 for retaining the liquefied material in the exhaust gas from the melting furnace main body 2 is formed in the lower portion of the ash melting furnace flue 20, and the liquefied material is contained in the slag water cooling tank 8 and a dust discharge hopper described later. 10 is prevented from flowing into the inside. The height h _{1 of} the first weir 21 from the bottom inside the ash melting furnace flue 20 (see FIG. 2A) and the height of the second weir 22 from the bottom inside the ash melting furnace flue 20 The relationship with h ₂ (see FIG. 2B) is h ₁ <h ₂ . By doing so, when the liquefied material exceeding the retention capacity of the retention portion 25 is generated while corresponding to the rise in the interface of the liquefied material in the vicinity of the second weir 22 due to the influence of the exhaust gas flow from the melting furnace main body 2, The liquefied material is allowed to overflow into the slag water cooling tank 8.
[0016]
A dust discharge hopper 10 is connected to the downstream end portion of the exhaust gas flow of the ash melting furnace flue 20. The dust discharge hopper 10 has a cylindrical structure, and an upper portion thereof is connected to a combustion chamber (not shown), and a hopper portion formed in a lower portion is formed in a funnel shape for discharging dust or the like in exhaust gas from the bottom portion. 10a is formed.
[0017]
In the exhaust gas treatment system of the present embodiment configured as described above, the material to be melted introduced into the incineration ash charging chute 3 is melted by the burner 6 in the melting furnace body 2 of the ash melting furnace 1 to form molten slag. . The molten slag is dropped into the slag water cooling tank 8, cooled and crushed, and then discharged out of the system by the slag carry-out conveyor 9. On the other hand, a gas containing a large amount of salts, heavy metals and the like generated in the melting furnace main body 2 is sent as an exhaust gas from the slag tap 7 through the ash melting furnace flue 20 into the dust discharge hopper 10. Then, the gas component of the exhaust gas is fed into a combustion chamber (not shown) from above the dust discharge hopper 10, and the dust and the like in the exhaust gas are discharged from the hopper portion 10a of the dust discharge hopper 10 and arranged below. Not carried out by the dust carry-out conveyor.
[0018]
At the start-up of the ash melting furnace 1 in the exhaust gas treatment system of this embodiment, the temperature of the ash melting furnace flue 20 itself is low. For example, exhaust gas of about 1300 ° C. discharged from the melting furnace body 2 is exhausted. When the temperature falls as it flows downstream in the ash melting furnace flue 20 and the temperature falls to around 950 ° C., which is the boiling point of the NaCl compound, salts and the like mainly composed of the NaCl compound contained in the exhaust gas are liquefied. To do. The liquefied salts and the like (liquefied material) are a first weir 21 provided on the upstream side of the ash melting furnace flue 20 and a second weir 22 provided on the downstream side of the ash melting furnace flue 20. And retained in the retaining portion 25 formed by the inner bottom of the ash melting furnace flue 20. At this time, even when the liquefied product is excessively generated in the ash melting furnace flue 20 and exceeds the retention capacity of the retention portion 25, the height h1 of the _first weir 21 is the same as described above. Since the height is set lower than the height h ₂ of the second weir 22, the liquefied material overflows over the first weir 21 and flows into the slag water cooling tank 8.
[0019]
As the ash melting furnace 1 shifts to normal operation, the temperature in the ash melting furnace flue 20 rises due to the radiant heat from the refractory material of the ash melting furnace flue 20 and is retained in the retention part 25. The liquefied material is gasified, and this gas is sent to the dust discharge hopper 10 together with the exhaust gas discharged from the melting furnace body 2 and further sent to a combustion chamber (not shown).
[0020]
According to the present embodiment, the liquefied material generated in the ash melting furnace flue 20 is retained in the retaining portion 25 formed in the ash melting furnace flue 20, and the liquefied material is fire-resistant in the ash melting furnace flue 20. It can be gasified using the radiant heat of an object and discharged downstream. Further, even if the liquefied material is excessively generated in the ash melting furnace flue 20, the excess liquefied material exceeds the first weir 21 provided on the upstream side of the ash melting furnace flue 20. It can be overflowed and discharged into the slag water cooling tank 8. Therefore, it is possible to reliably prevent the liquefied material from flowing into the dust discharge hopper 10, and avoid problems such as solidification of the liquefied material and clogging of the dust discharge hopper 10.
[0021]
In the present embodiment, an example is shown in which the ash melting furnace flue 20 is connected to the slag tap 7 and the dust discharge hopper 10 so that the conduction direction of the ash melting furnace flue 20 is horizontal. Here, as a modification of this embodiment, the ash melting furnace flue is inclined so that the downstream end of the ash melting furnace flue is at a higher position with respect to the upstream end, and the bottom of the ash melting furnace flue and the ash A retention part is formed with the weir provided at the upstream end of the melting furnace flue, and the liquefied material is retained in this retention part. The second weir on the downstream side of the ash melting furnace flue 20 in this embodiment. Even in a structure in which 22 is not required, it is possible to obtain the same operation and effect as in the present embodiment.
[Brief description of the drawings]
FIG. 1 is a configuration diagram of a main part of an exhaust gas treatment system for an ash melting furnace according to an embodiment of the present invention.
2A is an enlarged sectional view taken along line XX in FIG. 1, and FIG. 2B is an enlarged sectional view taken along line YY in FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Ash melting furnace 2 Melting furnace main body 7 Slag tap 20 Ash melting furnace flue 21 1st weir 22 2nd weir 25 A retention part

Claims (3)

An ash melting furnace flue structure connected to and connected to an ash melting furnace to lead the exhaust gas from the ash melting furnace downstream, wherein the liquefied material in the exhaust gas is liquefied in the ash melting furnace flue A flue structure for an ash melting furnace, characterized in that a retention means for retaining the ash melting furnace is provided. 2. The retention means includes a first weir provided at an upstream end portion of the ash melting furnace flue and a second weir provided at a downstream end portion of the ash melting furnace flue. The flue structure of the ash melting furnace described in 1. The stagnation means has a configuration in which the ash melting furnace flue is inclined so as to rise upward toward the downstream end side, and a weir is provided at the upstream end of the ash melting furnace flue. The flue structure of the ash melting furnace according to 1.

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