JP4886293B2 - Humidification incineration ash melting furnace - Google Patents

Description

  The present invention relates to a melting furnace for melting humidified incineration ash generated in refuse incineration processing or the like.

  As a general waste treatment method, a method based on soil is widely adopted in which general waste is incinerated to be incinerated, and the incinerated ash thus generated is transported to a landfill or the like. However, in recent years, it has become difficult to create landfills because soil contamination is caused by metal components contained in incinerated ash. Therefore, even if the incinerated ash is used for landfill, it is necessary to treat it to a form that does not cause soil contamination. Moreover, it is more preferable if it can be effectively used as a resource of incineration ash.

  Therefore, recently, incineration ash is melted to form a slag and solidified (see, for example, Patent Document 1), and as an incineration ash melting furnace used for such processing, For example, there is a swirl melting furnace (see, for example, Patent Documents 2 and 3).

  A swirling melting furnace is a solid type furnace with a melting slag outlet at the bottom of the furnace and a combustion exhaust outlet at the top of the furnace, incinerated from a powder blowing nozzle located at the bottom of the furnace. Injecting the object to be treated such as ash together with air, injecting the fuel from the fuel burner, combusting the combustible component while forming a swirling flow in the furnace, melting the inorganic component into slag, The generated molten slag adheres to the inner wall of the furnace due to the centrifugal force generated by the swirling flow, flows down along the wall surface, and is discharged from the discharge port at the lower part of the furnace.

  However, in the conventional swirl melting furnace, even if the surface of the object to be processed is melted, if it adheres to the furnace wall, it may flow down along the furnace wall including the undissolved part. is there. Therefore, there is a possibility that harmful metals and the like are mixed in the molten slag without being melted. Such slag cannot be reused as a resource at ease.

  On the other hand, in order to prevent such an incomplete melting problem from occurring, a large amount of energy is required for the combustion treatment in the furnace body, resulting in a problem that the operating cost increases. In particular, since the incineration ash contains a certain amount of moisture, a part of the heat for melting the humidified incineration ash is used to evaporate the moisture. Therefore, more energy is required to completely melt the workpiece.

In a conventional swirl melting furnace, combustion gas is discharged from the upper part of the furnace, and this combustion gas generally contains unburned components. A secondary combustion chamber is provided for burning the fuel. In such a configuration, fuel for operation of the secondary combustion chamber is required, and the heat generated in the secondary combustion chamber is not used for melting the object to be processed in the furnace body and has low thermal efficiency. Since it is a structure, there also exists a problem that operation cost increases.
Japanese Patent Laid-Open No. 9-60829 JP 11-294734 A Japanese Patent Laid-Open No. 11-159729

  The present invention has been made in view of such circumstances, and an object thereof is to provide a humidified incineration ash melting furnace capable of completely melting humidified incineration ash without melting unevenness, and having high thermal efficiency and low operating cost. And

According to the present invention, the cylindrical vertical primary melting furnace for drying the humidified incineration ash and performing primary melting, and the primary melting furnace are provided integrally with the primary melting furnace below the primary melting furnace. A cylindrical vertical secondary melting furnace for secondary melting of the primary melt generated in the furnace, wherein the primary melting furnace is capable of introducing gas from the upper end opening, and the lower end opening A primary melting furnace main body for discharging the primary melt from, a humidified incineration ash supply unit for supplying humidified incinerated ash to the primary melting furnace main body, generating hot air swirled inside the primary melting furnace main body, In order to dry the humidified incineration ash supplied to the inside of the primary melting furnace main body with the hot air, in order to primarily melt the heated incinerator ash that discharges hot air along the inner wall of the main melting furnace main body. It has a primary melting burner, a pre The secondary melting furnace has a secondary melting furnace body through which the primary melt flows from the upper end opening and discharges the secondary melt from the lower end opening, and the secondary melting furnace body for receiving the primary melt. A cylindrical vertical primary melting furnace having a crucible part disposed inside and a secondary melting burner for secondary melting of the primary melt in the crucible part, and connected vertically A humidified incineration ash melting furnace characterized by melting humidified incineration ash in two stages by a cylindrical vertical secondary melting furnace is provided.

  In the secondary melting by the humidified incineration ash melting furnace, the primary melt is preferably completely melted by the heat supplied from the secondary melting burner and the heat supplied from the primary melting furnace.

  In addition, as a more preferable configuration of the humidified incineration ash melting furnace, both the primary melting furnace and the secondary melting furnace are cylindrical, and this primary melting furnace can introduce gas from its upper end opening, and its lower end opening. A primary melting furnace body for discharging the primary melt from the main body, a humidified incineration ash supply section for supplying humidified incineration ash to the primary melting furnace body, and generating hot air swirling inside the primary melting furnace body, A heating burner that discharges hot air along the inner wall of the main body of the primary melting furnace and primary melting for primary melting of the dry incineration ash so as to dry the humidified incineration ash supplied to the inside of the main body of the primary melting furnace by hot air It is the structure which has a burner. It is preferable that a plurality of heating burners are provided. In that case, the plurality of heating burners are provided in the primary melting furnace main body while being displaced in the vertical direction. It is preferable to discharge the exhaust gas from the furnace from the secondary melting furnace. For this purpose, an exhaust duct is provided in the secondary melting furnace.

  Moreover, it is preferable to provide a cooling water tank for solidifying the secondary melt discharged from the secondary melting furnace in the humidified incineration ash melting furnace below the secondary melting furnace. The cooling water tank preferably has a structure including a high-pressure water injection mechanism that supplies high-pressure water to the secondary melt discharged from the secondary melting furnace to crush and cool the melt. Moreover, it is preferable to provide the crushing solidified material discharge | emission mechanism for discharging | emitting the crushing solidified material settled in the cooling water tank outside continuously.

  According to the humidified incineration ash melting furnace of the present invention, the humidified incineration ash can be completely melted because the primary melt is retained and further melted in the secondary melting furnace. Thereby, since a harmful metal etc. can be made into a chemically stable state in the solidified material obtained by cooling molten slag, this solidified material can be used safely. The humidified incineration ash melting furnace of the present invention has high heat utilization efficiency and can be operated at a low cost.

  In addition, the crushed solidified material obtained by being processed by the humidified incineration ash melting furnace of the present invention is, for example, as a road base material, as a substitute for pebbles or sand, and as a resource such as a concrete product or a refractory material. Can be used effectively.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a vertical sectional view showing a schematic structure of a humidified incineration ash melting furnace. The humidified incineration ash melting furnace 10 dries the humidified incineration ash and performs melting of the generated incinerated ash in two stages. Hereinafter, the first melting process is referred to as “primary melting”. The next-stage melting process performed to completely melt the primary melt produced in this way will be referred to as “secondary melting”.

  The humidified incineration ash melting furnace 10 includes a primary melting furnace 12 for drying the humidified incineration ash and performing primary melting, and a primary melting furnace 12 for secondary melting the primary melt generated in the primary melting furnace 12. A secondary melting furnace 14 provided integrally with the primary melting furnace 12 on the lower side, and a secondary melting furnace 14 in order to solidify the secondary melt (molten slag) discharged from the secondary melting furnace 14 A cooling water tank 16 is provided on the side.

  The primary melting furnace 12 is a cylindrical vertical type, into which gas (usually air) can be introduced from the upper end opening 21a, and the primary melting furnace main body 21 for discharging the primary melt from the lower end opening 21b, and the primary melting furnace A raw material hopper 22 serving as a humidified incineration ash supply unit for supplying humidified incinerated ash to the main body 21, a heating burner 23 for heating and drying the humidified incinerated ash supplied to the inside of the primary melting furnace main body 21, and dry incinerated ash And a primary melting burner 24 for performing primary melting.

  The primary melting furnace body 21 has a structure in which a refractory / heat-resistant building material 26 is attached to the inner wall of an outer cylinder 25 made of steel plate. The size and shape (inner / outer diameter and height) of the primary melting furnace main body 21 are designed in consideration of a desired processing capacity. The upper end opening 21 a may be provided with a shutter mechanism that can adjust the aperture ratio, and such a shutter mechanism contributes to airflow control in the primary melting furnace main body 21.

  The raw material hopper 22 is provided in the upper part of the primary melting furnace main body 21, and the humidified incineration ash supplied from the raw material hopper 22 to the inside of the primary melting furnace main body 21 is heated by the heating burner 23 while the primary melting furnace main body 21 is heated. Go down 21. Although the raw material hopper 22 is shown only in one place in FIG. 1, you may provide it in two or more places, for example.

  For example, three heating burners 23 are arranged shifted in the vertical direction (only two are shown in FIG. 1). Depending on the heat supplied from the heating burner 23, the capacity of the heating burner 23 is set so that the humidified incineration ash does not melt. FIG. 2 schematically shows the arrangement of the heating burners 23. As described above, the three heating burners 23 are arranged so as to be shifted in the vertical direction, but in FIG. 2, they are shown in the same plane.

  The heating burner 23 uses, for example, gas or heavy oil as a fuel, and hot air is released from the heating burner 23. The heating burner 23 is a primary melting furnace main body so that this hot air turns inside the primary melting furnace main body 21, in other words, a swirling flow by flowing along the furnace wall in the primary melting furnace main body 21. 21.

  With such a configuration, it is possible to generate a swirling flow in which the flow velocity does not decrease and the temperature does not decrease from the upper part to the lower part of the primary melting furnace main body 21. The humidified incineration ash supplied from the raw material hopper 22 to the inside of the primary melting furnace main body 21 is entrained in this swirling flow and dried by heating. At this time, the humidified incineration ash is simply added inside the primary melting furnace main body 21. Since it falls while turning inside the primary melting furnace main body 21 without being dropped, the moving distance and the heating time are lengthened, whereby the humidified incinerated ash can be reliably dried. Moreover, since the height of the primary melting furnace main body 21 can be kept low, the primary melting furnace 11 can be downsized.

  It is preferable to supply the humidified incinerated ash from the raw material hopper 22 along the inner wall of the primary melting furnace main body 21 because the humidified incinerated ash can be easily put on the swirling flow.

  For example, three primary melting burners 24 can be arranged in the lower part of the primary melting furnace main body 21. The primary melting burner 24 is directed toward the lower end opening 21b of the primary melting furnace main body 21 so that the hot air discharged from the primary melting burner 24 does not generate turbulent flow inside the primary melting furnace main body 21, and The hot air is disposed along the wall surface of the primary melting furnace main body 21. The dry incineration ash is melted by heating from the primary melting burner 24, and the primary melt thus generated descends to the secondary melting furnace 14. The primary melt need not be completely melted.

  Since the heat of the hot air discharged from the heating burner 23 is also used for the production of the primary melt, the heat from the heating burner 23 is effectively used. Further, the swirl flow generated by the heating burner 23 and the hot air by the primary melting burner 24 are used to drop the primary melt into the secondary melting furnace 14.

  The secondary melting furnace 14 is a cylindrical vertical type, and the upper end opening 31a communicates with the lower end opening 21b of the primary melting furnace main body 21, and the secondary melting furnace main body discharges the secondary melt from the lower end opening 31b. 31, a crucible 32 for receiving the primary melt discharged from the primary melting furnace 12, and a secondary melting burner 33 for completely melting the primary melt in the crucible 32.

  Similar to the primary melting furnace main body 21, the secondary melting furnace main body 31 has a structure in which a refractory / heat-resistant building material 36 is attached to the inner wall of an outer cylinder 35 made of a steel plate. As the crucible 32, a material made of a material having good corrosion resistance to the secondary melt (for example, a material made of the same material as the furnace construction material 36 or a material made of corrosion-resistant ceramics) is preferably used. The primary melt that has dropped from the primary melting furnace 12 to the secondary melting furnace 14 is received by the crucible 32, where it stays for a certain period of time, and is completely melted by heating by the secondary melting burner 33. The secondary melt thus generated overflows from the crucible 32 and falls into the cooling water tank 16 through the lower end opening 31b.

  The secondary melting burner 33 is preferably arranged so as to radiate hot air toward the center of the upper surface of the crucible 32 so that the secondary melt overflowing from the crucible 32 does not contain a solid component. By arranging the three secondary melting burners 33 radially at equal intervals, the entire upper surface of the crucible 32 can be heated uniformly, and the remaining of the solid component can be prevented.

  Thus, by providing the crucible 32 inside the secondary melting furnace main body 31, a secondary melt containing no solid content can be generated. Thereby, the harmful metals contained in the humidified incineration ash can be in a chemically stable state in a solidified product obtained by solidifying the secondary melt later. Therefore, such a solidified material can be used as various materials and materials with peace of mind. For example, when the humidified incineration ash contains heavy metal, such heavy metal may be stored at the bottom of the crucible 32 without overflowing from the crucible 32. Such substances can be removed and separated in regular maintenance.

  In addition to the heat of the hot air generated by the secondary melting burner 33, the heat of the swirl flow generated by the heating burner 23 generated in the primary melting furnace 12 and the heat of the hot air generated by the primary melting burner 24 are also used for generating the secondary melt. The That is, in the humidified incineration ash melting furnace 10, the heat generated in the primary melting furnace 12 is also effectively used in the secondary melting furnace 14, so that the heat utilization efficiency is high, and thus the operating cost (that is, the burner fuel cost). ) Can be kept low.

  The secondary melting furnace 14 is provided with an exhaust duct 34 for discharging hot air after being used for generating the secondary melt to the outside. FIG. 3 is a horizontal sectional view showing a schematic configuration of the exhaust duct 34. The exhaust duct 34 is provided with exhaust ports 34a at a plurality of locations (three locations in FIG. 3) on the side wall of the secondary melting furnace body 31 so that turbulent flow does not occur in the secondary melting furnace 14, and exhausts from there. Each exhaust gas is collected by an annular pipe 34b provided so as to surround the secondary melting furnace main body 31, and exhausted to the outside through a straight pipe 34c. The exhaust gas discharged to the outside through the exhaust duct 34 is sent to a gas processing facility equipped with a filter or the like (not shown), where it is processed into a clean gas and released into the atmosphere. At this time, if hot water supply using the heat of the exhaust gas is performed, the heat utilization efficiency can be further increased.

  The cooling water tank 16 is a high-pressure water jet that injects cooling water at a predetermined water pressure toward the upper center of the cooling water tank 16 in order to cool and crush the secondary melt discharged from the secondary melting furnace 14 with high-pressure water. A nozzle 41 is provided. Further, a solidified material discharge device 44 is provided at the lower end of the cooling water tank 16 to generate a linear water flow in the horizontal direction and continuously discharge the crushed solidified material cooled and crushed by the force of the water flow to the outside. ing. A certain amount of water is stored in the cooling water tank 16 by balancing the amount of cooling water supplied into the cooling water tank 16 and the amount of water used for discharging the crushed solidified material and discharged from the cooling water tank 16. Is done.

  The high-pressure water sprayed from the high-pressure water spray nozzle 41 cools and crushes the secondary melt at a position higher than the level of water stored in the cooling water tank 16. The small pieces of crushed solidified product thus generated fall into the water stored in the cooling water tank 16, where they are further cooled and settle to the bottom of the cooling water tank 16.

  In order to assist crushing of the secondary melt with high-pressure water, it is also preferable to provide a conical protrusion 42 at the center of the cooling water tank 16. Since the falling secondary melt is expanded in a conical shape by the protrusions 42, the secondary melt is easily crushed with high-pressure water.

  A chiller (circulation cooling device) 43 is attached to the cooling water tank 16 in order to keep the temperature of the stored water constant. Thereby, the cooling conditions of the secondary melt can be kept constant, and variations in the size and the like of the cooled crushed material can be prevented over time.

  Since the crushed solidified product settled in the cooling water tank 16 is fragmented and has a constant size, it can be easily and steadily recovered with a constant strength water flow.

  The crushed and solidified product is collected in a container having a bottom plate from which only water used for discharging it flows, while the water separated in this container is again crushed and solidified from the cooling water tank 16 by a circulation pump or the like. It can be used for carrying out.

  The humidified incineration ash melting furnace 10 can be designed in a size that takes into account its processing capacity, and can be easily downsized. Moreover, since the structure of the humidified incineration ash melting furnace 10 is simple, there is also an advantage that it can be manufactured at low cost.

  Although the embodiments and examples of the present invention have been described above, the present invention is not limited to such forms, and various modifications can be made within the scope of the technical idea of the present invention.

1 is a schematic vertical sectional view of a humidified incineration ash melting furnace according to an embodiment of the present invention. FIG. 2 is a schematic horizontal sectional view of the humidified incineration ash melting furnace shown in FIG. 1. FIG. 3 is another schematic horizontal sectional view of the humidified incineration ash melting furnace shown in FIG. 1.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Humidification incineration ash melting furnace, 12 ... Primary melting furnace, 14 ... Secondary melting furnace, 16 ... Cooling water tank, 21 ... Primary melting furnace main body, 21a ... Upper end opening part, 21b ... Lower end opening part, 22 ... Raw material hopper, 23 ... Heating burner, 24 ... Primary melting burner, 25 ... Outer cylinder, 26 ... Furnace material, 31 ... Secondary melting furnace body, 31a ... Upper end opening, 31b ... Lower end opening, 32 ... Crucible, 33 ... Secondary Melting burner, 34 ... exhaust duct, 34a ... exhaust port, 34b ... annular pipe, 34c ... straight pipe, 35 ... outer cylinder, 36 ... furnace material, 41 ... high pressure water injection nozzle, 42 ... projection, 43 ... chiller ( Circulating cooling device), 44 ... Solidified product discharging device.

Claims (5)

A cylindrical vertical primary melting furnace for drying humidified incineration ash and performing primary melting;
A cylindrical vertical secondary melting furnace provided integrally with the primary melting furnace below the primary melting furnace and for secondary melting of the primary melt generated in the primary melting furnace. ,
The primary melting furnace is:
A primary melting furnace main body capable of introducing gas from the upper end opening and discharging the primary melt from the lower end opening;
A humidified incineration ash supply unit for supplying humidified incineration ash to the primary melting furnace body;
Hot air is generated along the inner wall of the main body of the primary melting furnace so as to generate hot air swirling inside the main body of the primary melting furnace and to dry the humidified incinerated ash supplied to the inside of the main body of the primary melting furnace by the hot air. A heating burner that emits,
A primary melting burner for primarily melting the dried incineration ash,
The secondary melting furnace is
A secondary melting furnace body in which the primary melt flows in from the upper end opening and discharges the secondary melt from the lower end opening;
A crucible portion disposed inside the main body of the secondary melting furnace for receiving the primary melt;
A secondary melting burner for secondary melting of the primary melt in the crucible part, and a cylindrical vertical primary melting furnace and a cylindrical vertical secondary melting furnace which are integrally arranged vertically A humidified incineration ash melting furnace characterized by melting humidified incineration ash in two stages . It said heating burner plurality comprises, the plurality of heating burners, humidification ash melting furnace according to claim 1, characterized in that provided by shifting the position in the vertical direction to the primary melting furnace main body. The humidified incineration ash melt according to claim 2 , wherein the secondary melting furnace further comprises an exhaust duct for discharging the hot air as exhaust gas after the hot air is used for the secondary melting. Furnace. A cooling water tank for solidifying the secondary melt discharged from the secondary melting furnace is provided on the lower side of the secondary melting furnace,
The cooling water tank includes a high pressure water injection mechanism for supplying high pressure water to the secondary melt discharged from the secondary melting furnace to crush and cool the secondary melt. humidification ash melting furnace according to 3. The humidified incineration ash melting furnace according to claim 4 , further comprising a crushed solidified material discharge mechanism for continuously discharging the crushed solidified material settled in the cooling water tank to the outside.

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