JP4386597B2 - Waste incineration equipment - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention includes a combustion part capable of incinerating waste, and a catalyst part for decomposing a harmful substance contained in the exhaust gas with a catalyst with respect to the exhaust gas discharged from the combustion part during the incineration process, It relates to a waste incineration facility.
[0002]
[Prior art]
In general, when waste is incinerated in an incineration chamber of an incineration facility (or melting facility), exhaust gas containing harmful substances is discharged along with the incineration, so the exhaust gas is rendered harmless by a catalyst in a catalyst tower. A decomposition process is performed.
[0003]
Conventionally, in this exhaust gas decomposition treatment, as shown in FIG. 4 as an example, a high-temperature exhaust gas g discharged from the combustion furnace 41 is introduced into a waste heat boiler 42 or a heat exchanger (not shown) and heated. After the recovery process, the exhaust gas g is cooled to about 200 ° C. or less in the cooling tower 43, and then the dust removal process is performed by the bag filter device 44. After that, the dust-exhaust exhaust gas g is introduced into the re-heating chamber 45, re-heated to raise the temperature, and then sent to the catalyst tower 46 to decompose the harmful substances by the catalyst. It should be noted that after the dust is removed, the catalyst is preferably decomposed, and the bag filter device cannot withstand use at a high temperature of about 200 ° C. or higher. This is because there is a technical background that the decomposition treatment with the catalyst is active in a temperature range of 200 to 300 ° C.
[0004]
[Problems to be solved by the invention]
According to the above-described conventional technology, it is necessary to raise the temperature of the exhaust gas before decomposing the harmful substances contained in the exhaust gas in the catalyst tower, so that heat energy is required and the energy consumption increases. There is a problem.
Furthermore, since the exhaust gas in a high temperature state discharged from the combustion section is cooled at a relatively slow speed by a waste heat boiler or the like before being dust-removed, a temperature range in which dioxins are particularly likely to be generated among harmful substances. The time at the temperature (about 300 to 500 ° C.) becomes longer, and at that time, the heavy metal component contained in the exhaust gas acts as a catalyst to cause synthesis (resynthesis) reaction of dioxins, and dioxins are generated. There is an easy problem.
[0005]
The present invention has been made in view of the above circumstances, and the object thereof is to eliminate the need to perform a temperature raising process of exhaust gas when decomposing a harmful substance by the catalyst unit with respect to the exhaust gas generated from the combustion part. Therefore, it is an object of the present invention to provide a waste incineration facility that can reduce energy consumption for that purpose and can reduce the amount of dioxins released into the atmosphere.
[0006]
[Means for Solving the Problems]
As illustrated in FIG . 1 and FIG. 2 , the characteristic configuration of the invention of claim 1 is a combustion unit 1 capable of incinerating waste W, and an exhaust gas g discharged from the combustion unit 1 during the incineration process. On the other hand, a waste incineration facility having a catalyst part 4 for decomposing a harmful substance contained in the exhaust gas g with a catalyst,
The combustion section 1 includes a primary combustion chamber 11 and a secondary combustion chamber 12, and performs a combustion treatment of the waste W by low oxygen combustion in a temperature range of 300 to 500 ° C. in the primary combustion chamber 11, The exhaust gas g from the primary combustion chamber 11 is completely combusted in the temperature range of 800 to 1000 ° C. in the secondary combustion chamber 12,
By providing a mesh-like metal filter 21 having a water cooling structure and passing the exhaust gas g through the metal filter 21, the exhaust gas g is in a high temperature state discharged from the combustion unit 1, While providing a high-temperature dust removal unit 2 that performs dust removal treatment,
The relative gas g which has been treated at a high temperature dust portion 2, provided with a cooling unit 3 for quenching to by Ri catalytically active temperature water,
The exhaust gas g which has been processed by the cooling unit 3 is introduced into the catalytic section 4, it has rows the decomposition process, and,
An adsorption unit 5 that performs adsorption removal processing of the harmful substances with an adsorbent is provided for the exhaust gas g treated in the catalyst unit 4, and the exhaust gas treated in the catalyst unit 4 is introduced into the adsorption unit 5. Thus, the adsorption removal process is performed.
[0007]
[Function and effect]
In the high temperature dust removal unit, the dust removal process is performed in a high temperature state where the exhaust gas is discharged from the combustion unit, so that heavy metal components contained in the exhaust gas can be removed. Therefore, even if the exhaust gas that has passed through the high-temperature dust removal section is cooled and reaches a dioxin generation (resynthesis) temperature range (about 300 to 500 ° C.), it is a heavy metal component that serves as a catalyst for dioxin synthesis (resynthesis) reaction. Therefore, the synthesis reaction of dioxins can be suppressed and the generation of dioxins can be prevented.
In addition, since the exhaust gas treated in the high temperature dust removal unit is rapidly cooled with water in the cooling unit, the state in which the exhaust gas is in the dioxin generation temperature range is extremely short, and the catalyst is temporarily Even if the heavy metal component to be contained is contained in the exhaust gas, generation of dioxins due to the above-described synthesis reaction can be suppressed, and dioxins can be made difficult to generate.
Further, since the exhaust gas treated in the cooling part is introduced into the catalyst part and decomposed by the catalyst, the temperature of the exhaust gas introduced into the catalyst part is adjusted by appropriately adjusting the cooling temperature of the exhaust gas in the cooling part. If the temperature is set to about 200 to 300 ° C., the exhaust gas can be decomposed in a temperature range in which the decomposition reaction by the catalyst is active without the need for temperature increase treatment of the exhaust gas.
[0008]
Therefore, according to this configuration, it is not necessary to perform the temperature raising process of the exhaust gas when performing the decomposition process of the harmful substance by the catalyst unit, the energy consumption for that purpose can be reduced, and it is released into the atmosphere. The amount of dioxins released can be reduced.
[0009]
Conventionally, when exhaust gas is cooled, it is a technique that mainly uses air, so the cooling efficiency is not so high. Therefore, the capacity (volume) of a processing apparatus (for example, a cooling tower) for performing the cooling process is small. It became very large, and there were problems with installation area and cost.
However, as in the cooling section of this configuration, according to the rapid cooling process with water, by using the latent heat of vaporization of water, the exhaust gas can be rapidly cooled in an extremely short time as described above. Compared with the apparatus for processing, the capacity can be reduced to 1/2 to 1/3, and the cost and installation area can be reduced.
Therefore, according to this configuration, the incineration facility can be made into a small facility, and is particularly suitable for a facility using a small incinerator or a melting furnace.
[0011]
Further, according to the characteristic configuration of the invention described in claim 1, in the primary combustion chamber, since the waste is burned by low oxygen combustion, the waste is thermally decomposed by slow combustion in a low oxygen state. In particular, the generation of dioxins among harmful substances can be suppressed. Moreover, since harmful components such as HCl and SOx are generated not as a gas but as a dust of chloride or sulfide, they can be easily removed by an exhaust gas treatment system such as a high-temperature dust removal unit or a catalyst unit.
Moreover, in the secondary combustion chamber, the exhaust gas from the primary combustion chamber is completely burned in a high temperature (about 800 ° C. or higher) atmosphere, so even if dioxins are generated in the combustion process in the primary combustion chamber, the dioxin is generated. Can be decomposed and reduced.
[0012]
Therefore, according to the present configuration, the amount of dioxins generated in the incineration section can be reduced, and the risk of dioxins being released into the atmosphere can be further reduced. It can be removed easily and the amount released to the atmosphere can be reduced.
[0014]
Furthermore, according to the characteristic configuration of the invention described in claim 1, by using a mesh-shaped metal filter, it is possible to perform dust removal treatment of exhaust gas in a high temperature state (about 600 ° C. or higher), and the metal filter Since it has a water cooling structure, it can guarantee long-term durability against the treatment of exhaust gas in a high temperature state.
[0015]
Moreover, since the bag filter mainly used as a processing apparatus in the conventional dust removal processing is intended to remove very fine dust, the filtration speed is usually 1 to 2 m / min. There is a problem that the processing apparatus becomes very slow, and the cost of the processing apparatus is also a problem when a small incinerator or melting furnace is used.
On the other hand, according to the present configuration, the purpose is to collect relatively coarse dust by the mesh-shaped metal filter, so that the filtration rate can be set to m / sec unit, and the exhaust gas by passing through the metal filter. It is also possible to reduce the pressure loss. Therefore, as a result, the weight and volume of the processing device itself of the high temperature dust removing unit can be reduced.
[0016]
Therefore, the dust removal treatment of the exhaust gas in a high temperature state can be performed conveniently, and the incineration facility can be made a small facility.
In addition, according to the characteristic configuration of the invention described in claim 1, the exhaust gas treated in the catalyst portion is further subjected to the adsorption removal treatment of harmful substances by the adsorbent in the adsorption portion. The harmful substances contained in can be completely removed.
Accordingly, it is possible to provide a waste incineration facility that contributes to environmental conservation by reliably eliminating the possibility of harmful substances being released into the atmosphere.
[0017]
The characteristic configuration of the invention according to claim 2 is that, in addition to the feature configuration according to claim 1 , the mesh surface 21b, 21c of the metal filter 21 is inclined with respect to the vertical direction as illustrated in FIG. It is arranged to be in a posture,
Above the mesh surfaces 21b and 21c, there is provided a nozzle 28 through which compressed air 27 can be blown to the mesh surfaces 21b and 21c.
[0018]
[Function and effect]
The metal filter is disposed so that the mesh surface is inclined with respect to the vertical direction, and a nozzle is provided above the mesh surface so that compressed air can be blown onto the mesh surface. Therefore, the inflow direction of the exhaust gas to the metal filter is made to pass from the mesh surface on the lower surface side of the metal filter to the mesh surface on the upper surface side, and the nozzle is positioned on the outflow direction of the exhaust gas that has passed through the metal filter. It can be configured so that there is no.
[0019]
With this configuration, when dust collected on the metal filter is blown off by blowing compressed air from the nozzle, the dust that has been wiped off falls from the lower surface side of the metal filter. It will not be mixed into the exhaust gas on the outflow side that has passed. Therefore, while maintaining the dust removal efficiency of the metal filter, it is possible to prevent the dust from being mixed again into the exhaust gas flowing out from the high temperature dust removal unit, and as a result, it is possible to prevent the dust from being discharged into the atmosphere. It is. In addition, since the nozzle is not on the outflow direction of the exhaust gas in a relatively high temperature state, the nozzle is prevented from being deteriorated by being directly exposed to the high temperature exhaust gas, and the durability of the nozzle is improved. You can also.
[0020]
Therefore, it is possible to prevent harmful substances from being released into the atmosphere with simple equipment while maintaining the dust removal efficiency in the high temperature dust removal section, and to maintain such performance over a long period of time.
[0021]
According to a third aspect of the present invention, in addition to the first or second aspect, the cooling unit is configured by spraying water having a particle diameter of 50 μm or less on the exhaust gas. The exhaust gas is configured to be rapidly cooled.
[0022]
[Function and effect]
When performing the rapid cooling treatment of exhaust gas with water, it is necessary to take care not to generate waste liquid, and thus it is necessary to completely evaporate such water in a short time.
Therefore, by spraying water having a particle size of 50 μm or less as in this configuration, the water is easily and completely evaporated quickly, and waste liquid can be reliably prevented from being generated in the rapid cooling process.
[0025]
In addition, as mentioned above, although the code | symbol was written in order to make contrast with drawing convenient, this invention is not limited to the structure of an accompanying drawing by this entry.
[0026]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
[0027]
[First Embodiment]
In FIG. 1, explanatory drawing of one Embodiment of the waste incineration equipment which concerns on this invention is shown.
[0028]
As shown in FIG. 1, the waste incineration equipment includes an incinerator 1, a dust removing device 2, a cooling tower 3, a catalyst tower 4, and an adsorption tower 5. Exhaust gas g generated as a result of incineration is treated as follows.
That is, the exhaust gas g is discharged from the incinerator 1 and then sent to the dust removing device 2 where it is subjected to dust removal processing at a high temperature state. The exhaust gas g subjected to the dust removal treatment is sent to the cooling tower 3 and rapidly cooled with water in a short time, and then guided to the catalyst tower 4 in a temperature range of about 250 ° C. The harmful substances contained in the exhaust gas g guided to the catalyst tower 4 are decomposed by the catalyst, and further, the exhaust gas g is sent to the adsorption tower 5 and the harmful substances are adsorbed and removed by the adsorbent. Hereinafter, each process will be described in more detail.
[0029]
The incinerator 1 corresponds to the incinerator in the present invention, and is a fixed bed incinerator in the present embodiment, and has a first combustion chamber 11 and a second combustion chamber 12, as shown in FIG. In the first combustion chamber 11, waste is mainly combusted, and the gas component (exhaust gas) from the first combustion chamber 11 is completely burned in the second incineration chamber 12, and then the high-temperature dust removal as exhaust gas g. Sent to part 2.
[0030]
The first combustion chamber 11 includes a waste input device 13 and a city gas burner 14, and can burn the waste W such as city garbage input from the waste input device 13. Incidentally, an air amount of 0.2 to 0.5 of the theoretical air amount necessary for the combustion of the waste W is blown to the first combustion chamber 1 as the primary air 15 from the blower fan a, and the city gas burner 14 While maintaining the temperature, the waste W is thermally decomposed by gentle combustion in a low oxygen state in the temperature range of 300 to 500 ° C., thereby suppressing generation of dioxins among harmful substances, as well as HCl and SOx. Such harmful components can be generated in the form of dust and easily removed by a subsequent exhaust gas treatment system such as the dust removing device 2.
The second combustion chamber 12 is provided with a city gas burner 16 for maintaining the temperature, and the gas generated by the combustion process in the first combustion chamber 11 is completely burned. This complete combustion treatment is performed in a temperature range that is high enough to decompose dioxins. For example, it is necessary to burn the waste W as the secondary air 17 from the blower fan a to the second combustion chamber 12. This is carried out by blowing an air amount of 1.0 to 1.5 of the theoretical air amount and retaining the gas for 2 seconds or more in a temperature range of 800 to 1000 ° C. Therefore, even if dioxins are generated, the dioxins are almost completely decomposed in the second combustion chamber 12.
Thus, the incineration process is performed in the incinerator 1, and the exhaust gas g generated by the process is guided to the dust removing device 2. Note that the incineration ash generated by the combustion treatment of the waste W in the first combustion chamber 11 is separately discharged and processed as appropriate.
[0031]
The dust removing device 2 corresponds to the high-temperature dust removing unit in the present invention, and the introduced exhaust gas g is dust-removed in a temperature range of 600 to 1000 ° C., and is a catalyst for resynthesis of dioxins. The heavy metal component and dust such as HCl and SOx are removed. The dust removing device 2 may have any specific configuration as long as dust removal can be performed in such a high temperature range. For example, as shown in FIG. What is necessary is just to arrange | position the filter 21 so that the mesh surface 21a may cross | intersect the exhaust gas g which flows in in a substantially perpendicular | vertical attitude | position.
As shown in FIGS. 2 (a) and 2 (b), the metal filter 21 is configured by attaching a plate-shaped metal mesh 23 to a metal frame member 22 having a substantially rectangular shape in an elevational view, The frame member 22 is provided with a water cooling structure capable of cooling the metal filter 21 by fixing the water cooling pipe 24 and inserting the cooling water 25 through the water cooling pipe 24. In this embodiment, the cooling water 25 circulates through the water cooling pipe 24 and is discharged as hot water 26 by heat exchange with the metal filter 21 and is used for a rapid cooling process in the cooling tower 3 as will be described later.
[0032]
In the present embodiment, the metal mesh 23 is configured by overlapping a plurality of metal nets so that the meshes are arranged in a staggered manner (that is, not overlapping the same portion).
Incidentally, if the number of the metal nets is too small, sufficient dust removal treatment cannot be performed, and if too large, the pressure loss when passing the exhaust gas g increases, and the weight and capacity of the device itself increase. Moreover, since handling becomes complicated, it is preferable to set it as 5-20 sheets, and also about the magnitude | size of the mesh of the metal net | network, it is preferable to set it as 3.5-150 mesh for the same reason.
[0033]
The exhaust gas g thus dust-removed in a high temperature state is rapidly cooled to about 300 ° C. in the cooling tower 3 in an extremely short time. Therefore, the time during which the exhaust gas g is in the dioxin generation (resynthesis) temperature range (about 300 to 500 ° C.) is extremely short, and the risk of dioxins being generated (resynthesis) can be reduced. The cooling tower 3 corresponds to a cooling section in the present invention, and may be a quenching process of the exhaust gas g in a form appropriately utilizing the latent heat of vaporization of water. For example, hot water discharged from the dust removing device 2 described above If 26 is utilized, the rapid cooling process by water evaporation can be performed efficiently and promptly.
In this embodiment, compressed air 31 is mixed in addition to the warm water 26, and fine water 32 having a particle diameter of 50 μm or less is directly sprayed on the exhaust gas g in the cooling tower 3, thereby more efficiently and promptly. A rapid cooling process is performed.
[0034]
Incidentally, in this embodiment, in performing the quenching treatment with water, not only the cooling treatment but also the water content in the exhaust gas g after the quenching treatment is adjusted to be 10 to 30 vol%, and a catalyst described later. In the decomposition treatment with the catalyst in the column 4, the activity of the catalyst is increased so that the treatment can be performed efficiently.
[0035]
And the exhaust gas g cooled to 300 degreeC by the cooling tower 3 is guide | induced to the catalyst tower 4 by the induction fan b, and is processed. In this embodiment, the temperature is controlled by sucking the air 36 from the suction side of the induction fan b so that the exhaust gas is efficiently decomposed in the catalytically active temperature range (200 to 300 ° C.) during the catalyst treatment. The temperature of the exhaust gas g entering the catalyst tower 4 is set to about 250 ° C.
[0036]
The catalyst tower 4 corresponds to a catalyst part in the present invention. In the embodiment, harmful substances such as NOx mainly contained in the exhaust gas g are decomposed and removed by the denitration catalyst in the catalyst tower 4, Dioxins slightly contained in the exhaust gas g are also removed by the denitration catalyst.
[0037]
The exhaust gas decomposed by the catalyst tower 4 is further guided to the adsorption tower 5 (corresponding to the adsorption section), and is adsorbed by an adsorbent such as activated carbon, for example, and contains dioxins or other harmful substances slightly contained. Is removed. In this embodiment, in order to perform the adsorption process more efficiently, the air 37 in the atmosphere is blown by the blower fan c so that the temperature of the exhaust gas entering the adsorption tower 5 is 200 ° C. or less (for example, about 170 ° C.). The temperature is controlled by blowing air.
[0038]
As described above, according to the waste incineration facility according to the present invention, it is not necessary to perform the temperature raising process on the exhaust gas discharged from the incineration unit, thereby reducing the energy consumption, and the processing in the catalyst unit and the adsorption unit. The exhaust gas can be detoxified efficiently and reliably at an appropriate temperature, and the entire equipment can be made compact and economical can be improved.
[0039]
[Second Embodiment]
In the dust removing device 2, the metal filter 21 is disposed so that the mesh surface is inclined with respect to the vertical direction, and above the mesh surface, with respect to the mesh surface. If it is configured with a nozzle that can blow compressed air, it is possible to prevent harmful substances from being released into the atmosphere while maintaining dust removal efficiency, and to maintain such performance over a long period of time. It becomes possible and can be more preferable.
[0040]
That is, as shown in FIG. 3 as an example, if the metal filter 21 is disposed in an inclined posture, dust collected on the metal filter 21 is blown off when the compressed air 27 is blown off from the nozzle 28. Since the dust dust 29 drops from the lower surface 21b side of the metal filter, it will not be mixed into the exhaust gas g 'on the outflow side after passing through the upper surface 21c side of the metal filter 21.
[0041]
[Another embodiment]
Other embodiments will be described below.
<1> In the present invention, the incineration section may be of any method as long as waste can be incinerated, and includes, for example, a rotary incinerator such as a fluidized bed incinerator and a rotary kiln, and a stoker-type firebed. A stoker furnace may be used.
<2> In the waste incineration facility according to the present invention, it is of course possible to perform processing other than the processing described in the previous embodiment. In addition, the exhaust gas introduced from the incineration unit to the high temperature dust removal unit is subjected to other treatments as long as the effects of the present invention due to the dust removal treatment performed on the exhaust gas at the high temperature state discharged from the combustion unit are not impaired. You can go. For the same reason, other treatments may be performed on the exhaust gas between the high temperature dust removing unit and the cooling unit, between the cooling unit and the catalyst unit, and between the catalyst unit and the adsorption unit.
[Brief description of the drawings]
FIG. 1 is an explanatory view showing an embodiment of a waste incineration facility according to the present invention. FIG. 2 is an explanatory view showing an embodiment of a high temperature dust removing section according to the present invention. Explanatory drawing which shows embodiment. FIG. 4 is explanatory drawing which shows the conventional waste incineration equipment.
[Explanation of symbols]
g, g 'exhaust gas 1 incineration unit 2 high temperature dust removal unit 3 cooling unit 4 catalyst unit 5 adsorption unit 11 primary combustion chamber 12 secondary combustion chamber 21 metal filter 21a, 21b, 21c mesh surface 27 compressed air 28 nozzle W waste

Claims (3)

Waste having a combustion part capable of incinerating waste and a catalyst part for decomposing a harmful substance contained in the exhaust gas with a catalyst with respect to the exhaust gas discharged from the combustion part during the incineration process Incineration equipment,
The combustion section includes a primary combustion chamber and a secondary combustion chamber. The waste combustion process is performed by low oxygen combustion in a temperature range of 300 to 500 ° C. in the primary combustion chamber, and 800% in the secondary combustion chamber. Configured to perform complete combustion of exhaust gas from the primary combustion chamber in a temperature range of ~ 1000 ° C,
By providing a mesh-like metal filter having a water cooling structure, and passing the exhaust gas through the metal filter, the exhaust gas is subjected to dust removal treatment in a high temperature state discharged from the combustion section. the provided with a dust removing unit, with respect to the treated exhaust gas in the hot dust portion, until I Ri catalytically active temperature water provided with a cooling unit for performing rapid cooling process, the treated flue gas by the cooling unit is introduced into the catalyst unit, it has rows the decomposition process, and,
An adsorption unit that performs adsorption removal processing of the harmful substance with an adsorbent is provided for the exhaust gas treated in the catalyst unit, and the exhaust gas treated in the catalyst unit is introduced into the adsorption unit, so that the adsorption waste incineration facilities you have configured the removal process in line Migihitsuji. The metal filter is disposed so that the mesh surface is inclined with respect to the vertical direction,
2. A waste incineration facility according to claim 1, wherein a nozzle is provided above the mesh surface so that compressed air can be blown onto the mesh surface . The waste incinerator according to claim 1 or 2, wherein the cooling unit is configured to spray water with a particle size of 50 µm or less on the exhaust gas to quench the exhaust gas .

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