JP2002069461A - System for treating waste - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a system for treating wastes which is capable of efficiently producing a clean gas having a high quality, a high calorific value, and gives reduced amount of a NOx on combustion. SOLUTION: This system for treating wastes is provided with a thermal decomposition apparatus 1 which thermally decomposes wastes containing organic polymer materials in a reducing atmosphere, and with a reforming apparatus 2 which produces a combustible gas of a low molecular weight by partially combusting the thermally decomposed gas produced by the thermal decomposition apparatus, wherein the reforming apparatus has an injecting mechanism of water or steam at the introducing part 6 of the thermally decomposed gas. Further, the reforming apparatus may be provided with a spiral flow generating mechanism which passes continuously the thermally decomposed gas introduced into the apparatus with a spiral flow from the inlet to the outlet.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a waste treatment system, and in particular, to thermally decompose general waste or industrial waste containing an organic polymer substance to obtain a reformed fuel gas (clean gas). About the system.

[0002]

2. Description of the Related Art In recent years, various treatment methods have been proposed for the treatment of general waste or industrial waste, which has become a major social problem. One of the methods is the following pyrolysis method. is there. That is, the gas component (pyrolysis gas) generated by thermally decomposing waste containing an organic polymer substance in a reducing atmosphere is reformed into a high-calorie clean gas containing no harmful components. A method of extracting energy from waste and reducing the amount of waste finally sent to landfill by obtaining heat by burning coal or recovering it as a clean gas and using it as fuel for other heat engines There is.

[0003] The system of such a waste treatment system is as follows.
As shown in FIG. In this system, waste is put into a pyrolysis furnace 51 called a rotary kiln, where it is heated by a kiln heating burner (not shown) and pyrolyzed in a reduced state. By this thermal decomposition, the combustible components of the waste become pyrolysis gas, and residues such as metals are generated.
The pyrolysis gas generated in the pyrolysis furnace 51 is sent to a reformer 52 at a later stage.

[0004] The reformer 52 includes a cylindrical first column 53 and a second column 54, and a communication section 55 for communicating these columns at the lower portion.
And heated to a high temperature of about 1100 ° C. by a burner using city gas, kerosene or the like as a fuel. About 1100 ° C
As the carbon content C in the pyrolysis gas sent into the reformer 52 held in the column flows through the column, a reaction represented by the following chemical formula C + H ₂ O → H ₂ + CO occurs. , So that H ₂ and CO
Is generated as a main component.

[0005] Here, C is supplied as various hydrocarbon components such as C _n H _m of the pyrolysis gas, H 2 _O, the initial pyrolysis gas is introduced into the reformer 52, city gas After that, a part of H _{2 in} the pyrolysis gas is burned in the reformer 52 by a burner using fuel or kerosene as a fuel. Further, the combustion heat of the H _2, reformer 5
2 can be maintained at a temperature of about 1100 ° C.

The combustible gas thus generated by the reformer 52 passes through a bag filter 56, which is a filtration type dust collector, and solids (dust) in the gas are removed. Next, nitrogen-containing components such as HCN and NH ₃ are removed by the gas post-processing device 57, and the thus obtained clean gas is used as fuel.

[0007] In the reformer 52, the structure of a combustor 58 for burning part of the pyrolysis gas (partial combustion) is shown in FIG.
These are shown in (a) and (b), respectively. In this combustor 58, a pyrolysis gas injection port 59 is arranged at the center, and a plurality of air ejection ports 60 are arranged around the injection port 59 at equal intervals. Then, the pyrolysis gas blown from the pyrolysis gas blow-in port 59 comes into contact with the air blown out from the air blowout port 60 and burns by raising the flame. Reformer 52
In order to make the inside a reducing atmosphere, the amount of supplied air is small, and the pyrolysis gas burns by the amount of oxygen in the supplied air.

The flow of the pyrolysis gas in the reformer 52 is
An arrow is shown in FIGS. 10 (a) and (b). The pyrolysis gas is supplied to the first tower 53 and the communication section 55 maintained at about 1100 ° C.
And slowly pass through the second column 54, so that H ₂
Conversion and reforming to CO gas proceed. Further, since the flow of the pyrolysis gas in the reformer 52 is swirled as shown below, the swirling causes the components in the gas to be more mixed, thereby reforming the gas into H ₂ and CO. Advances.

That is, the pyrolyzed gas combustor 58 is tangentially attached to the upper part of the cylindrical first tower 53, and the pyrolyzed gas blown from the blowing port 59 of the combustor 58 is supplied to the first column 53. It descends while turning inside the tower 53. Then, while flowing through the communicating portion 55 between the second tower 54, the swirling component is reduced, and the pyrolysis gas flowing into the second tower 54 from the bottom rises as it is without swirling. It flows out from the outlet at the top of 54.

[0010]

The conventional waste treatment system configured as described above has the following problems. That is, in the conventional reformer 52, HCN is generated in the combustor 58 of the pyrolysis gas. When fuel is burned (reacted with air) in an oxidizing atmosphere, N ₂ and O ₂ in the air react in a high-temperature flame, and
Although it is known that O is generated, in the reformer 52 which is a reducing atmosphere, HC is generated in a high-temperature flame of the pyrolysis gas.
N is generated and is contained in the combustible gas exiting the reformer 52 at a rate of several hundred ppm to several thousand ppm.

The HCN is removed by the gas post-processing device 57. However, if a large amount of HCN is generated, the HCN cannot be completely removed by the gas post-processing device 57 or costs a large amount. When the clean gas containing HCN is burned, nitrogen oxides (NO _x ) are finally generated, so that there is a problem that a denitration device or the like for removing the nitrogen oxides is required. Was.

Further, all of the pyrolysis gas generated from the pyrolysis furnace 51 is not converted and reformed into a flammable gas such as H ₂ , CO, or CH ₄ in the reformer 52, and carbon and carbon are not converted. Solids such as high molecular weight hydrocarbons are generated, and these solids are collected by the bag filter 56 as combustible dust.
Removed. When the amount of such combustible dust is large, the amount of generated clean gas is reduced accordingly, and the calorific value is reduced. The amount of combustible dust generated is affected by the temperature in the reformer 52, the residence time of the pyrolysis gas passing through the reformer 52, the degree of mixing of components, and the like. It is desired to obtain a clean gas having a large calorific value.

[0013] The present invention has been made in view of these circumstances, to provide a waste treatment system a large high-quality clean gas generation amount is small calorific value of the NO _x efficiently produced by combustion Aim.

[0014]

According to a first aspect of the present invention, there is provided a waste treatment system for thermally decomposing a waste containing an organic polymer material in a reducing atmosphere. A waste treatment system comprising: a reforming device that heats and partially combusts the pyrolysis gas generated by the pyrolysis device to generate a low molecular weight combustible gas; And a mechanism for injecting water or steam into the combustion section for blowing the pyrolysis gas into the combustion section.

In such a first waste treatment system, a plurality of air outlets are arranged on a circumference surrounding a blowing port of the pyrolysis gas to the reformer. In addition, it is possible to adopt a structure in which a plurality of injection ports for injecting water or water vapor are arranged between air injection ports adjacent on the same circumference as these air injection ports.

According to a third aspect of the present invention, a plurality of air outlets are disposed on a circumference surrounding the inlet of the pyrolysis gas to the reformer, and these air outlets and the heat outlet are provided. A plurality of injection ports for injecting water or water vapor can be respectively arranged between the decomposition gas injection ports.

According to a second aspect of the present invention, there is provided a waste treatment system comprising: a thermal decomposition apparatus for thermally decomposing a waste containing an organic polymer material in a reducing atmosphere; In a waste treatment system including a reformer that heats the generated pyrolysis gas and partially burns the same to generate a low-molecular-weight combustible gas, water or water mixed with steam is supplied to the reformer. It has a supply mechanism.

[0018] In the second waste treatment system, a mechanism for supplying water or steam is connected to an intermediate portion of a pipe for supplying air to the reformer. It may be configured to supply air in which water or steam is mixed to the reformer.

According to a third aspect of the present invention, there is provided a waste treatment system comprising: a thermal decomposition apparatus for thermally decomposing waste containing an organic polymer material in a reducing atmosphere; A waste treatment system comprising a reformer for heating the generated pyrolysis gas and partially burning the same to generate a low-molecular-weight combustible gas, wherein the reformer is introduced into the apparatus. It is characterized by having a swirling flow generating mechanism for continuously passing the pyrolysis gas while swirling from the inlet to the outlet.

[0020] In the third waste treatment system, the reformer may include a first reforming tower that circulates the introduced pyrolysis gas from top to bottom. A second reforming tower that allows the pyrolysis gas to flow upward from below, and a communication portion that communicates the first reforming tower and the second reforming tower at their lower portions. A structure may be provided in which a flow path having a shape for generating a swirl flow in the pyrolysis gas is formed below the second reforming tower.

Further, as set forth in claim 8, the reforming apparatus comprises: a first reforming tower for flowing the introduced pyrolysis gas from top to bottom; A second reforming tower that allows the first reforming tower and the second reforming tower to communicate with each other at a lower portion thereof,
The communication section is disposed off a line connecting the center of the first reforming tower and the center of the second reforming tower, and passes through the communication section to form the second reforming tower. In such a configuration, a swirling flow may be generated in the pyrolysis gas.

According to a fourth aspect of the present invention, there is provided a waste treatment system comprising: a thermal decomposition apparatus for thermally decomposing waste containing an organic polymer material in a reducing atmosphere; In a waste treatment system including a reformer that heats the generated pyrolysis gas and partially burns to generate a low-molecular-weight combustible gas, a dust collector is provided at a subsequent stage of the reformer, It is characterized by having a mechanism that mixes the combustible dust collected by the dust collector with the fuel exhaust gas from the pyrolyzer and re-introduces it into the reformer.

In the waste treatment system according to the present invention, water or steam is injected into the combustion section of the pyrolysis gas in the reformer disposed downstream of the pyrolysis apparatus.
The amount of HCN generated can be suppressed by lowering the flame temperature. Therefore, it is possible to generate a clean gas that generates a small amount of nitrogen oxides (NO _x ) during combustion.

In addition, by generating a swirling flow also in the second tower of the reformer, the generation of combustible residues can be suppressed, and the calorific value of the clean gas can be increased. Further, by mixing the combustible residue discharged from the reformer with the exhaust gas from the heating burner of the pyrolysis device and returning the mixed gas to the inside of the reformer, a clean gas having a larger calorific value can be generated.

[0025]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a system diagram showing a first embodiment of the waste disposal system according to the present invention.

This waste treatment system comprises a pyrolysis furnace (for example, a rotary kiln) 1 for pyrolyzing waste containing an organic polymer material in a reducing atmosphere, and a pyrolysis gas generated in the pyrolysis furnace 1 at a high temperature. A reformer 2 for producing a low molecular weight combustible gas by heating with a heater, and a bag filter 3 for collecting and removing solids (combustible dust) in the gas generated by the reformer 2. , HCN and NH in gas
_And a gas post-treatment device 4 for removing nitrogen-containing compounds such as ₃ . Further, an evaporator 5 is provided for taking in exhaust gas from a kiln heating burner (not shown) for heating the pyrolysis furnace 1 and performing heat exchange. The steam generated by the evaporator 5 is configured to be injected into a pyrolysis gas combustion section (flame) of the pyrolyzer gas combustor 6. Further, the reformer 2 has a cylindrical first column 2a, a second column 2b, and a communicating portion 2c communicating these columns at the lower portion, and the combustor 6 of the pyrolysis gas is located at the upper portion of the first column 2a. Mounted on

The structure of the combustor 6 in the first embodiment is as follows.
These are shown in FIGS. 2A and 2B, respectively. This combustor 6
In the above, the blowout port 7 for injecting the pyrolysis gas is arranged at the center, and a plurality of air
And a plurality of steam injection ports 9 are arranged alternately.

In the waste treatment system of the first embodiment, the waste put into the pyrolysis furnace 1 is heated by a kiln heating burner in a reducing atmosphere to be thermally decomposed. It becomes gas and nonflammable residues such as metals remain. The pyrolysis gas thus generated in the pyrolysis furnace 1 is injected into the reformer ₂ and partially burns with air (partial combustion), and the remainder burns with a flammable gas containing H ₂ and CO as main components. It becomes an acidic residue. The gas exhausted from the reformer 2 is combustible residue removed by the bag filter 3 and then passes through the gas post-processing device 4 to be used as a clean gas for fuel or the like.

In the first embodiment, in the combustor 6 of the reformer 2, a plurality of air injection ports 8 and a plurality of steam injection ports are provided on the same circumference around the injection port 7 for the pyrolysis gas. 9 are arranged alternately, and steam is directly injected into the combustion section (flame section) where the jetted pyrolysis gas comes into contact with air, so that the temperature of the flame of the pyrolysis gas is reduced. As a result, generation of HCN in the reformer 2 is suppressed, so that a clean gas containing almost no HCN can be obtained. Therefore, the emission of the NO _x generated when burning a clean gas, gas treatment apparatus 4
Can be reduced without imposing a load on the vehicle.

In this embodiment, the steam generated in the evaporator 5 by heat exchange with the exhaust gas from the kiln heating burner is injected into the combustion section of the reformer 2 where the pyrolysis gas is burned. The method of generating steam is not limited to this, and includes a method of generating steam using waste heat generated by burning a clean gas, a method of obtaining steam by a separately installed evaporator, a method of using existing steam, and the like. is there.

Next, second and third embodiments of the present invention will be described.

In the second embodiment, the reformer 2 is provided with a combustor 6 having the following structure. That is, in the combustor 6, as shown in FIGS. 3 (a) and 3 (b), a centrally disposed blow-out port 7 for the pyrolysis gas.
A plurality of water vapor outlets 9 are disposed in a one-to-one correspondence with the air outlets 8 between the air outlets 8 and the plurality of air outlets 8 disposed on the circumference thereof. In addition, other parts
Since the configuration is the same as that of the first embodiment, the description is omitted.

In the second embodiment constructed as described above, similarly to the first embodiment, the flame temperature can be reduced by injecting steam into the combustion section of the pyrolysis gas.
Thereby, the generation amount of HCN in the reformer 2 can be reduced. Therefore, the emission of the NO _x generated during combustion of the clean gas can be reduced without imposing a load on the gas post-processing device 4.

In the third embodiment, as shown in FIG. 4, the steam discharge pipe 10 from the evaporator 5 is connected to the reformer 2.
Is connected to an intermediate portion of a pipe 11 for blowing air into the combustor 6, so that air mixed with steam is blown into the reformer 2. The other components of the system are configured in the same manner as in FIG.

In the third embodiment constructed as described above, the air in which steam is previously mixed is blown into the combustor 6 of the reformer 2 to effectively reduce the temperature of the flame of the pyrolysis gas. HCN in the reformer 2
Is reduced. Therefore, the emission of the NO _x generated during combustion of the clean gas can be reduced without imposing a load on the gas post-processing device 4.

Next, fourth and fifth embodiments of the present invention will be described. In these embodiments, the pyrolysis gas introduced into the reformer 2 is configured to flow while continuously swirling from the inlet above the first column 2a to the outlet above the second column b. ing.

In the fourth embodiment, as shown in FIGS. 5A and 5B, the second column 2b of the reformer 2
A refractory block 12 having a flow passage 12a shaped to generate a swirl flow in the pyrolysis gas is formed at the lower part of the block.

In the fifth embodiment, as shown in FIGS. 6A and 6B, the communicating portion 2c between the first tower 2a and the second tower 2b is located on a line connecting the centers of the respective towers. From the second tower 2b by passing through the communication portion 2c.
The pyrolysis gas flowing into the inside is configured to swirl.

In these embodiments, the pyrolysis gas flowing into the second column 2b through the communicating portion 2c rises while swirling, and flows out from the discharge port provided above the second column 2b. The dead space (denoted by D in FIG. 10) that is not used for the flow of the pyrolysis gas inside the second column 2b is reduced, the mixing of gas components is promoted, and the pyrolysis gas in the reformer 2 is also reduced. Residence time also increases. As a result, the amount of combustible residues generated decreases, and the amount of combustible gas provided as fuel increases, so that the calorific value of the clean gas increases.

Next, a sixth embodiment of the present invention will be described.

In the sixth embodiment, as shown in FIG. 7, of the combustible gas and the combustible residue generated in the reformer 2,
After the combustible residue (main component is carbon C) recovered by the bag filter 3 is mixed with the exhaust gas from the kiln heating burner, the combustible residue is returned to the upstream portion of the first column 2a of the reformer 2 again.
It is configured to be heat-treated.

In the sixth embodiment configured as described above,
A reaction represented by the following chemical formula occurs in the combustible residue containing carbon as a main component returned to the reformer 2, thereby generating CO, which is a main component of the clean gas. C + CO ₂ → 2CO C + ／ O ₂ → CO C + H ₂ O → H ₂ + CO Therefore, it is possible to obtain a clean gas having a small amount of combustible dust and a large calorific value.

[0044]

As is apparent from the above description, according to the waste treatment system of the present invention, HCN is generated by injecting water or steam into the combustion section of the pyrolysis gas in the reformer. Can be suppressed, and NO
It is possible to generate a clean gas with a small x generation amount.

Further, by generating a swirling flow in the second tower of the reformer, the generation of combustible residues can be suppressed, and the calorific value of the clean gas can be increased. Further, by mixing the combustible residue discharged from the reformer with the exhaust gas from the heating burner of the pyrolyzer and returning the mixed gas to the inside of the reformer, a clean gas having an increased calorific value can be generated. .

[Brief description of the drawings]

FIG. 1 is a schematic system diagram showing a first embodiment of a waste treatment system according to the present invention.

FIGS. 2A and 2B show the structure of a combustor according to a first embodiment of the present invention, wherein FIG. 2A is a front view of an open end, and FIG.

3A and 3B show a structure of a combustor according to a second embodiment of the present invention, wherein FIG. 3A is a front view of an open end, and FIG. 3B is a cross-sectional view taken along line AA in FIG.

FIG. 4 is a schematic system diagram showing a third embodiment of the waste treatment system according to the present invention.

FIG. 5 shows a structure of a reformer and a flow of a pyrolysis gas in the reformer according to a fourth embodiment of the present invention;
Is a horizontal sectional view, and (b) is a vertical sectional view.

FIG. 6 shows a structure of a reformer and a flow of a pyrolysis gas in the reformer according to a fifth embodiment of the present invention;
Is a horizontal sectional view, and (b) is a vertical sectional view.

FIG. 7 is a schematic system diagram showing a sixth embodiment of the present invention.

FIG. 8 is a system diagram showing a schematic configuration of a conventional waste treatment system.

FIG. 9 shows the structure of a combustor in a conventional waste treatment system, where (a) is a front view of an open end, and (b) is (a).
AA sectional drawing in.

FIG. 10 shows a structure of a reformer in a conventional waste treatment system and a flow of a pyrolysis gas in the reformer;
(A) is a sectional view in the horizontal direction, and (b) is a sectional view in the vertical direction.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Pyrolysis furnace 2 ... Reformer 3 ... Bag filter 4 ... Gas post-processing apparatus 5 ... Evaporator 6 ... Combustor 7 ... Spray port for blowing pyrolysis gas 8 Air outlet 9 Water vapor outlet 12 Fireproof block

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) F23G 5/14 ZAB B09B 3/00 ZAB

Claims (9)

[Claims] 1. A pyrolyzer for thermally decomposing waste containing an organic polymer material in a reducing atmosphere, and a pyrolysis gas generated by the pyrolyzer is partially burned by heating to produce a low molecular weight flammable gas. A waste treatment system comprising a reformer for generating gas, wherein the reformer has a mechanism for injecting water or steam into a blowing and burning section of the pyrolysis gas to the device. Waste treatment system. 2. A plurality of air outlets are arranged on a circumference surrounding a blowing port of the pyrolysis gas to the reformer, and are adjacent on the same circumference as these air outlets. 2. A plurality of jets for jetting water or water vapor are provided between the air jets, respectively.
Waste treatment system as described. 3. A plurality of air outlets are provided on a circumference surrounding a blowing port of the pyrolysis gas to the reformer, and these air blowing ports, the pyrolysis gas blowing port, 2. The waste treatment system according to claim 1, wherein a plurality of injection ports for injecting water or steam are provided between the plurality of injection ports. 4. A pyrolyzer for thermally decomposing a waste containing an organic polymer material in a reducing atmosphere, and a pyrolysis gas generated by the pyrolyzer is partially burned by heating to produce a low molecular weight flammable gas. A waste treatment system comprising: a reformer for generating gas; and a mechanism for supplying air mixed with water or steam to the reformer. 5. A mechanism for supplying water or steam is connected to an intermediate portion of a pipe for supplying air to the reformer, so that air mixed with water or steam is supplied to the reformer. The waste treatment system according to claim 4, wherein the waste treatment system is configured. 6. A pyrolyzer for thermally decomposing a waste containing an organic polymer material in a reducing atmosphere, and a pyrolysis gas generated by the pyrolyzer is partially burned by heating to produce a low molecular weight flammable gas. A waste treatment system comprising a reformer for generating gas; a swirl flow in which the reformer passes while continuously rotating the pyrolysis gas introduced into the device from an inlet to an outlet. A waste treatment system having a generation mechanism. 7. A first reforming tower for flowing the introduced pyrolysis gas from top to bottom, and a second reformer for flowing the pyrolysis gas from bottom to top. And a communication section for communicating the first reforming tower and the second reforming tower at respective lower portions, and swirling the pyrolysis gas at the lower portion of the second reforming tower. The waste treatment system according to claim 6, wherein a flow path having a shape for generating a flow is formed. 8. A first reforming tower for flowing the introduced pyrolysis gas from top to bottom, and a second reformer for flowing the pyrolysis gas from bottom to top. And a communication section communicating the first reforming tower and the second reforming tower at their lower portions, wherein the communication section is connected to the center of the first reforming tower and the second reforming tower. It is arranged so as to be off the line connecting the center of the reforming tower, and by passing through this communication part, a swirling flow is generated in the pyrolysis gas in the second reforming tower. The waste treatment system according to claim 6, wherein 9. A pyrolyzer for thermally decomposing waste containing an organic polymer material in a reducing atmosphere, and a pyrolysis gas generated by the pyrolyzer is heated and partially burned to produce a low molecular weight flammable gas. A waste treatment system including a reformer that generates gas, a dust collector provided at a stage subsequent to the reformer, and combustible dust collected by the dust collector is supplied from a fuel from the pyrolyzer. A waste treatment system comprising a mechanism for mixing with exhaust gas and introducing the mixture into the reformer again.