JP3586599B2 - Waste incinerator with boiler - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a waste incinerator with a boiler, and particularly, a secondary combustion zone in which combustion gas products and the like are reburned is provided above a primary combustion chamber into which waste is charged, and at least the secondary combustion zone is provided. The present invention relates to a waste incinerator with a boiler in which a water tube assembly is surrounded by a refractory on an outer and inner wall side.
[0002]
[Prior art]
Conventionally, stoker type incinerators and fluidized bed type incinerators have been the mainstream of waste incinerators, but in both cases above the primary combustion chamber where the waste is injected, combustion gas products etc. Is provided with a secondary combustion zone in which the secondary air is reburned, complete combustion is achieved by effectively blowing secondary air, and dioxin and the like are reduced.
On the other hand, in order to effectively use the waste heat obtained from the waste, a boiler water pipe is arranged on the inner wall side of the furnace wall (including the inside of the furnace wall) forming the primary combustion chamber and a secondary combustion area above the primary combustion chamber. are doing.
FIG. 4 shows a schematic side view of a waste incinerator with a boiler in which a boiler water pipe is provided in a conventional stoker-type incinerator.
In FIG. 4, reference numeral 11 denotes an input hopper into which waste enters, 12 denotes a supply feeder that extrudes the waste to the stoker side while drying the waste, and 13 denotes a stoker that burns the dried waste. A primary combustion chamber is provided above the stoker. 13A are formed. Numeral 30 is a combustion gas generated by burning waste in the primary combustion chamber 13A on the stoker 13.
[0003]
Reference numeral 14 denotes a boiler for recovering the heat of the combustion gas 30 generated on the stoker 13, which is shown in FIGS. 2 and 3 on the primary combustion chamber 13A and the secondary combustion chamber 16, and further on the inner side of the furnace wall. Such a water pipe assembly 22 (FIGS. 2 and 3 are embodiments of the present invention) is configured to be bent. Reference numeral 15 denotes a mixing section in which the mixing of the combustion gas 30 is promoted, such as by reducing the cross sectional area of the combustion gas 30 or by blowing air or exhaust gas, and is generally provided with a secondary air supply nozzle 29. Reference numeral 16 denotes a reburning region (secondary burning region) located above the mixing section 15, where dioxin and the like can be reduced by retaining the combustion gas 30 at approximately 850 ° C. or more for 2 seconds or more.
On the inner wall side of the furnace wall, a refractory 17 for protecting the water pipe assembly 22 in the secondary combustion zone 16 from the high-temperature combustion gas 30 is disposed, and the refractory is used to dispose the water pipe assembly 22 located outside thereof. It is configured to cover from the combustion gas 30.
[0004]
[Problems to be solved by the invention]
The refractory is generally formed of a refractory block and mortar. Besides protecting the water pipe assembly 22 from the high-temperature combustion gas 30, the waste burns and becomes fly ash, and the fly ash melts to become a clinker. Therefore, it is necessary to prevent the waste incinerator from operating and becoming inoperable due to adhesion to the refractory 17 and growing. Therefore, as a material of the refractory 17, a silicon carbide refractory having a high thermal conductivity is mainly used.
[0005]
However, such a conventional technique has the following problems.
That is, in recent years, dioxin emitted from waste incineration facilities has become a social problem, and in order to suppress the emission of dioxin, it is desirable that the combustion gas 30 be retained at a high temperature for a long time in the secondary combustion zone 16. . However, conventionally, in the entire region of the secondary combustion region 16, a silicon carbide refractory having a high thermal conductivity is used to prevent the adhesion of clinker, and the combustion gas 30 in the secondary combustion region 16 is easily cooled, In order to suppress the emission of dioxin, it works counterproductively.
[0006]
In view of such technical problems, the present invention protects a boiler water pipe from high-temperature combustion gas, prevents melting of waste combustion fly ash, and prevents clinker from growing on a refractory as a clinker. It is an object of the present invention to provide a boiler-equipped waste incinerator for preventing the generation of dioxin by securing a residence time of combustion gas at a high temperature, in particular, a configuration of a boiler water wall refractory.
[0007]
[Means for Solving the Problems]
For the present invention to solve such problems, above the primary combustion chamber waste is turned on, provided the secondary combustion zone of the combustion gas product or the like is re-burned, refractory to at least the secondary combustion zone In a waste incinerator with a boiler in which a water pipe assembly is arranged via a material,
The first gist is that at least a part of the refractory material surrounding the secondary combustion zone is divided into upper and lower parts, and the lower refractory is formed of a material having good thermal conductivity relative to the upper refractory. I have.
[0008]
Further, in the present invention, among the secondary combustion zones, the upper secondary combustion zone burns combustion gas products and the like at a temperature of approximately 850 ° C. to 950 ° C., while the lower refractory surface temperature of the lower secondary combustion zone is substantially reduced. The refractory material and the shape of the water tube assembly are selected so that the combustion gas product or the like is burned at a temperature of 850 ° C. or less ,
The water pipe assembly shape is composed of boiler water pipes and flat ribs connecting the water pipes in the horizontal direction or the vertical direction to reinforce the water pipes, and the refractory material is made of an outer peripheral surface and a flat rib of the water pipe of the water pipe assembly. The gist is also formed so as to conform to the shape of the surface. Here, the reason why the temperature is set to approximately 850 ° C. is in consideration of the combustion temperature for reducing dioxin.
[0009]
The refractory is generally formed of a refractory block and a mortar. Of these refractory materials, the lower refractory material is mainly composed of SiC or a thin castable material, while the upper refractory material is Al _2. It is preferable that any one of O ₃ , SiO ₂ , Zr ₂ O ₃ , Cr ₂ O ₃ , MgO, and SiC is used as a main component, or it is a thick castable .
[0010]
And in front Symbol refractories are formed by refractory blocks and mortar, constitute a mortar between the case before Symbol refractory block and the water tube assembly with mortar having two or more different thermal conductivities Mortars having different thermal conductivities may be vertically arranged such that the lower part of the secondary combustion zone and the upper part of the secondary combustion zone have relatively good thermal conductivity .
[0011]
According to this invention, in the secondary combustion zone, the lower refractory is divided into upper and lower refractory materials having different thermal conductivities in the lower secondary combustion zone and the upper secondary combustion zone, and the lower refractory is relative to the upper refractory. The high-temperature combustion gas generated in the secondary air mixing section on the primary combustion chamber is made of a material with high thermal conductivity, so the refractory material with high thermal conductivity is used in the lower layer of the secondary combustion section. When passing through the lower part because the temperature is lowered by the boiler water pipe, the refractory surface temperature is reduced to approximately 850 ° C. or less. This adhesion can be prevented without adhering to the wall.
[0012]
Further, the combustion gas once cooled to approximately 850 ° C. to 950 ° C. or lower passes through the lower part 16a of the secondary combustion part and then passes through the upper part of the secondary combustion area, where a refractory having a low thermal conductivity is applied. As a result, the combustion gas temperature is maintained at about 900 ° C. without being cooled by the boiler water pipe, and recombustion is performed. As a result, the combustion gas can be retained at a high temperature for a long time, thereby suppressing the generation of dioxin. be able to.
In other words, refractories having different thermal conductivities are vertically divided in the secondary combustion area 16 to protect the water pipe of the boiler from the high-temperature combustion gas 30 while burning the waste to produce fly ash. It is possible to prevent the molten gas from becoming a clinker and sticking to the refractory and growing, and furthermore, it is possible to secure the residence time of the combustion gas at a high temperature.
[0013]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the present invention will be described in detail using embodiments shown in the drawings. However, unless otherwise specified, the dimensions, shapes, relative arrangements, and the like of the components described in this embodiment are not intended to limit the scope of the present invention, but are merely illustrative examples.
[0014]
FIG. 1 shows an embodiment of the present invention, and FIG. 4 shows a schematic side view of a waste incinerator with a boiler in which a boiler water pipe is arranged in a conventional stoker type incinerator.
In FIG. 1, reference numeral 11 denotes an input hopper into which waste enters, 12 denotes a supply feeder that extrudes the waste to a stoker side while drying the waste, and 13 denotes a stoker that burns the dried waste. A primary combustion chamber is provided above the stoker. 13A are formed. Numeral 30 is a combustion gas generated by burning waste in the primary combustion chamber 13A on the stoker 13.
[0015]
Reference numeral 14 denotes a boiler for recovering the heat of the combustion gas 30 generated on the stoker. The boiler is provided on the primary combustion chamber 13A and the secondary combustion chamber 16, and further on the inner side of the furnace wall above the water pipe shown in FIGS. The assembly 22 is configured to be bent. Reference numeral 15 denotes a mixing section in which the mixing of the combustion gas 30 is promoted, such as by reducing the cross sectional area of the combustion gas 30 or by blowing air or exhaust gas, and is generally provided with a secondary air supply nozzle 29. Reference numerals 16a and 16b denote secondary combustion chambers (lower and upper portions of the secondary combustion zone) located above the mixing section 15, and the inner wall of the furnace wall is provided with a water pipe assembly 22 of the secondary combustion zone 16 for high-temperature combustion. Refractory materials 17a and 17b for protecting from gas 30 are arranged vertically with different thermal conductivities in the upper layer portion and the lower layer portion, and are disposed outside by the refractory members 17a and 17b. It is configured to cover 22 from the combustion gas 30.
[0016]
In the present embodiment, the refractory is formed of a refractory block and a mortar, but in the present embodiment, the thermal conductivity of the refractory block is different. That is, reference numeral 17a denotes a refractory block constructed in the lower part 16a of the secondary combustion zone. In this lower part, the temperature of the combustion gas 30 is considerably high and clinker easily adheres. The temperature is lowered to approximately 850 ° C. or less by increasing the heat absorption on the water tube assembly side, which is the boiler water tube, by using a high-temperature material.
Reference numeral 17b denotes a refractory block constructed on the upper part 16b of the secondary combustion zone, which passes through the lower part 16a of the secondary combustion zone using a refractory having a lower thermal conductivity than the refractory block 17a, such as alumina. The emission of dioxins is suppressed while maintaining the temperature of the recombusted combustion gas 30 at a high temperature of 850 ° C. or higher.
[0017]
2 and 3 show the construction of a refractory block constructed in the lower part 16a of the secondary combustion zone and the upper part 16b of the secondary combustion zone. In the drawings, reference numeral 20 denotes a boiler water pipe, and 21 denotes a horizontal or vertical direction between the water pipes 20. A water pipe assembly 22 is formed by the water pipes 20 and the flat ribs 21 with plane ribs for connection and reinforcement in the directions.
Reference numeral 17a denotes a refractory block provided to cover the water pipe assembly 21 from the combustion gas 30 in the lower part 16a of the secondary combustion zone. An arm 18 is provided upright on the flat rib 21 of the water pipe assembly 22. On the other hand, a concave portion 19 corresponding to the arm portion 18 is formed in the refractory block 17a. The mortar 23 is filled between each of the arm portions 18 and the concave portions 19 and between the water pipe assembly 22 and the refractory block.
In FIG. 3, reference numeral 17b denotes a refractory block provided so as to cover the water pipe assembly 21 from the combustion gas 30 in the upper part 16b of the secondary combustion zone.
[0018]
In the present embodiment, one of the refractories formed of the refractory blocks 17a and 17b and the mortar 23 may be made to have different thermal conductivity physically or chemically.
A physically different method is to change the thickness of the castables forming the refractory blocks 17a and 17b. That is, the inner lower refractory block 17a of the refractory block is made of a thin castable, while the upper refractory block 17b is made of a relatively thick castable.
Although the thickness of the mortar may be changed, it is necessary to consider the adhesiveness.
As a method of chemically changing the material, the material of the inner lower refractory block 17a of the refractory block is formed by castable mainly composed of SiC, while the material of the upper refractory block 17b is Al ₂ O ₃ , SiO ₂ , Zr ₂ O ₃ , Cr. ₂ O _3, any of MgO may be formed in castable mainly.
Further, instead of the refractory block 17 side, the mortar between the refractory block and the water pipe assembly may be constituted by mortar 23 having two or more kinds of different thermal conductivity.
[0019]
According to such an embodiment, in the secondary combustion zone 16, the refractory blocks 17a having different thermal conductivities so that the lower portion of the secondary combustion zone lower portion 16a and the upper portion of the secondary combustion zone 16b have relatively good thermal conductivity. And the refractory block 17b or mortar are vertically divided. As a result, the high-temperature combustion gas 30 generated in the primary combustion chamber on the stoker 13 is absorbed by the boiler water pipe side when passing through the lower secondary combustion area 16a on which the refractory having a high thermal conductivity is installed, and the fire resistance is reduced. The object surface temperature can be set to a low temperature of approximately 850 ° C. or less, so that fly ash can be prevented from melting and clinker generation and adhesion can be prevented.
[0020]
After passing through the lower portion 16a of the secondary combustion zone, the combustion gas that has dropped to about 850 ° C. passes through the upper portion of the secondary combustion zone while reburning, because a refractory having a low thermal conductivity is installed here. The temperature of the combustion gas is raised by the above-mentioned re-combustion and maintained at a temperature of about 900 ° C. Thereby, the combustion gas can be retained at a high temperature for a long time in the upper part of the secondary combustion region, and the generation of dioxin can be suppressed.
In other words, the refractory blocks or mortars having different thermal conductivities are divided into upper and lower layers physically or chemically in the secondary combustion zone 16 so that the lower layer has good thermal conductivity, so that the boiler water pipe is heated with high temperature combustion gas. While protecting from the waste, the fly ash generated by the burning of the waste is prevented from melting, thereby preventing it from becoming a clinker and adhering to and growing on the refractory. It is possible to secure a residence time.
[0021]
【The invention's effect】
As described above, according to the present invention, while protecting the boiler water pipe from high-temperature combustion gas, it prevents melting of the combustion fly ash of the waste and prevents it from growing as a clinker attached to the refractory, The retention time of the combustion gas at a high temperature can be ensured to prevent the generation of dioxin.
[Brief description of the drawings]
FIG. 1 is a side view showing an outline of a waste incinerator with a boiler according to a first embodiment of the present invention.
FIG. 2 is a cross-sectional view taken along the line AA of FIG. 1 and particularly shows a configuration of a refractory and a water pipe assembly constituting a lower secondary combustion zone.
FIG. 3 is a cross-sectional view taken along the line BB of FIG. 1, particularly showing a configuration of a refractory and a water pipe assembly constituting an upper secondary combustion zone.
FIG. 4 is a side view showing an outline of a waste incinerator with a boiler according to the related art.
[Explanation of symbols]
11 Input hopper 12 Supply feeder 13 Stalker 13A Primary combustion chamber 14 Boiler 15 Combustion gas mixing section 16 Secondary combustion chamber (secondary combustion area)
17a Fireproof block 17b installed in lower part 16a of secondary combustion zone Fireproof block 22 installed in upper part 16b of secondary combustion area Water pipe assembly

Claims (5)

A secondary combustion zone in which combustion gas products and the like are reburned is provided above the primary combustion chamber into which waste is charged, and a water pipe assembly is disposed at least in the secondary combustion zone via a refractory. Waste incinerator with boiler
Surrounding the secondary combustion zone, the refractory formed of a refractory block and mortar is divided into upper and lower, and the lower refractory is formed of a material having good thermal conductivity relative to the upper refractory ,
Of the refractory blocks, the lower refractory block is formed of a material containing SiC as a main component, while the upper refractory block is formed of any one of Al ₂ O ₃ , SiO ₂ , Zr ₂ O ₃ , Cr ₂ O ₃ , and MgO. A waste incinerator with a boiler, characterized by being formed of a material mainly composed of: A secondary combustion zone in which combustion gas products and the like are reburned is provided above the primary combustion chamber into which waste is charged, and a water pipe assembly is disposed at least in the secondary combustion zone via a refractory. Waste incinerator with boiler
Surrounding the secondary combustion zone, the refractory formed of a refractory block and mortar is divided into upper and lower, and the lower refractory is formed of a material having good thermal conductivity relative to the upper refractory,
Wherein among the refractory block, the lower refractory block is a thin castable, while the upper layer refractory block characteristics and be Rubo Ira with waste incinerators that the thick castable. A secondary combustion zone in which combustion gas products and the like are reburned is provided above the primary combustion chamber into which waste is charged, and a water pipe assembly is disposed at least in the secondary combustion zone via a refractory. Waste incinerator with boiler
Surrounding the secondary combustion zone, the refractory formed of a refractory block and mortar is divided into upper and lower, and the lower refractory is formed of a material having good thermal conductivity relative to the upper refractory,
The mortar between the refractory block and the water pipe assembly is composed of mortar having two or more kinds of different thermal conductivity, and the lower part of the secondary combustion zone and the lower part of the secondary combustion area have relatively good heat conduction. features and be Rubo Ira with waste incinerators that the different thermal conductivity mortar so as to become a sex were divided tension up and down. Among the secondary combustion zones, the upper secondary combustion zone burns combustion gas products and the like at a temperature of approximately 850 ° C. to 950 ° C., while the lower refractory surface temperature of the lower secondary combustion zone is approximately 850 ° C. or lower. In such a way that the combustion gas products and the like are burned, the refractory material and the water pipe assembly shape are selected,
The water pipe assembly shape is composed of boiler water pipes and flat ribs connecting the water pipes in the horizontal direction or the vertical direction to reinforce the water pipes, and the refractory material is made of an outer peripheral surface and a flat rib of the water pipe of the water pipe assembly. The waste incinerator with a boiler according to claim 1 , wherein the waste incinerator is formed so as to conform to the surface shape of the boiler. The waste incinerator with a boiler is a stoker type incinerator, wherein the secondary combustion zone is located above a mixing section where a secondary air supply nozzle is provided and mixing of combustion gas is promoted. The waste incinerator with a boiler according to any one of claims 1 to 4 , wherein the waste incinerator is a chamber .

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