JP2000210516A - Apparatus and method for dust collection of incinerator flue gas - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an excellent dust collecting performance and an excellent hazardous material removing performance while a pressure loss is maintained low by a method wherein a backwashing device for backwashing a ceramic filter is provided, a reaction agent sprayer is provided upstream from the ceramic filter, and a ratio of filtration area to volume of the ceramic filter is specified. SOLUTION: As a dust collector 5, that equipped with an reaction agent sprayer arranged upstream from a backwashing device and a honeycomb filter. Each honeycomb filter has hundreds pieces of cells having a square section, and its ratio of filtration area to volume is 100 to 400. Further, a filtering flow velocity of an incinerator flue gas to be sent to the dust collector from the incinerator is adjusted, and backwashing is executed at intervals of 30 to 360 min. Furthermore as the reaction agent powdery slaked lime is used, and a spray condition is adjusted. Then, a state of clogging of the filter is investigated based on a pressure loss. That is, the incinerator gas is introduced to the honeycomb filter at a specific filtering flow velocity, the operation is continuously carried out by adjusting a backwashing condition, and a pressure loss before and after the filter is measured.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a dust collecting apparatus and a dust collecting method for removing dust from exhaust gas from an incinerator.

[0002]

2. Description of the Related Art In recent years, there has been a growing need to effectively collect exhaust gas from incinerators because dioxins contained in dust generated when garbage is incinerated seriously affect human bodies. ing. In addition, incinerator exhaust gas contains H
Cl, SO _x , NO _x , heavy metals and the like are also contained, and these also have a bad effect on the human body. Therefore, it is necessary to remove these harmful substances from incinerator exhaust gas.

[0003] Under such circumstances, a bag filter has conventionally been used for collecting dust from incinerator exhaust gas. Hazardous substances are removed by spraying a reactive agent such as slaked lime upstream of the bag filter to trap dust mixed with the reactive agent in the bag filter and passing the exhaust gas therethrough. And by reacting

On the other hand, ceramic filters have been used in various fields such as chemistry, electric power, steel and automobile-related industries for the purpose of recovering products from high-temperature gas. Such a ceramic filter is, for example, shown in FIG.
As shown in FIG. 3 and FIG. 3, it is effective to provide a configuration including a plurality of cells. In the multilayer ceramic filter of FIG. 2, dust in the high-temperature gas enters through the plurality of cell holes on the upstream side B, passes through the porous partition walls 2 formed on the upper and lower surfaces of the plurality of cells 1, and flows downstream of the side surface. When passing through the hole 6 on the side C, it is captured on the surface of the partition wall 2.

[0005] Further, in the honeycomb filter shown in FIG. 3 in which a large number of cells are partitioned by partition walls having pores, the ends of the large number of cells 1 of the honeycomb are separated by one cell in the upstream B and the downstream C in reverse. The high-temperature gas entering from the plurality of cell holes on the upstream side B passes through the porous partition walls 2 formed on the upper, lower, left and right surfaces of the plurality of cell holes, and then passes through the hole on the downstream side C. At this time, dust in the high-temperature gas is trapped on the surface of the partition wall 2. In the honeycomb filter, unlike the multilayer filter, the partition walls for capturing dust can be formed on the four surfaces of upper, lower, left, and right, so that the filtration area can be larger than that of the multilayer filter. Also, the laminated filter needs to be manufactured by lamination, but the honeycomb filter can be manufactured by one-piece molding, which is advantageous in terms of manufacturing cost.

[0006] Such a ceramic filter has heat resistance and is smaller than a bag filter in the case of the same filtration performance, so that it can be used at a high temperature if used for collecting exhaust gas from an incinerator. The dust device itself can be made compact.

[0007]

However, when a ceramic filter is used for collecting exhaust gas from an incinerator,
To remove harmful substances in the same way as in the case of bag filters, effective removal requires a large amount of reactive agent-coated dust to be retained on the inner wall of the cell. The pressure loss was increased, and in some cases, the cells could be blocked by a large amount of dust.

The present invention has been made in view of such circumstances, and has as its object to achieve the same level of dust collection performance and harmful substance removal performance as a bag filter while maintaining a low pressure loss. It is an object of the present invention to provide a dust collecting apparatus and a dust collecting method for incinerator exhaust gas which can be used.

[0009]

That is, according to the present invention, there is provided a dust collector for incinerator exhaust gas provided with a ceramic filter having a plurality of cells, wherein the backwash device for backwashing the ceramic filter is provided. In addition, a dust collector for incinerator exhaust gas is provided, which includes a reactant spraying device upstream of the ceramic filter and has a filtration area / volume ratio of the ceramic filter of 100 to 400.

In the above dust collector for incinerator exhaust gas, it is preferable that the reactant spray device is installed at least 1.5 m upstream from the ceramic filter. It is preferable that the backwashing of the ceramic filter is performed at intervals of 30 to 360 minutes. Furthermore, it is preferable that the above-mentioned dust collecting device for incinerator exhaust gas is provided with a collected dust recirculation device for introducing dust collected by the backwashing device upstream of the ceramic filter. Further, in the present invention, the reactant spraying device,
It is preferable to spray the reactant in the form of a slurry. Further, in the present invention, the reactant may be one or more agents selected from the group consisting of a desalinating agent, a denitrifying agent, a desulfurizing agent, a dedioxins agent and a heavy metals agent. Further, in the dust collector of the present invention, the ceramic filter may be a honeycomb filter.

Further, according to the present invention, there is provided a method for collecting exhaust gas from an incinerator using a ceramic filter having a plurality of cells, wherein the ceramic filter has a filtration area / volume ratio of 100 to 400, There is provided a method for collecting incinerator exhaust gas, in which harmful substances are removed from exhaust gas by spraying a reactant upstream of the filter, and the ceramic filter is backwashed.

In the above method for collecting exhaust gas from an incinerator, the reactant is sprayed 1.5 m from the ceramic filter.
It is preferable to perform the above upstream. It is preferable that the backwashing of the ceramic filter is performed at intervals of 30 to 360 minutes. Furthermore, in the above-described method for collecting exhaust gas from incinerator exhaust gas, it is preferable that the dust collected by the backwashing device is charged upstream of the ceramic filter and recirculated. or,
In the dust collection method of the present invention, it is preferable to spray a slurry-like reactant. Further, in the dust collecting method of the present invention, the reactant is 1 or 2 selected from the group consisting of a desalinating agent, a denitrifying agent, a desulfurizing agent, a de-dioxin agent and a heavy metal agent.
The above drugs may be used. Furthermore, in the dust collection method of the present invention, the ceramic filter may be a honeycomb filter.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, dust from incinerator exhaust gas is collected by a ceramic filter having a plurality of cells, and removal of harmful substances from incinerator exhaust gas is performed by spraying a reactant upstream of the ceramic filter. It is done by doing. Further, at the time of dust collection, the ceramic filter is backwashed, and the filtration area / volume ratio of the ceramic filter is set to 100 to 400.

The reason for setting the filtration area / volume ratio of the ceramic filter to 100 to 400 is that if the filtration area exceeds 400, the diameter of the cell becomes small, and the cell may be blocked by dust. In the present invention, the filtration area / volume ratio of the ceramic filter is set to 400 or less, and the backwashing of the ceramic filter prevents an increase in pressure loss and clogging of the cell. Makes dust possible. The reason why the filtration area / volume ratio of the ceramic filter is 100 or more is that if the filtration area is less than 100, the ceramic filter cannot be made more compact than the bag filter, and one of the advantages of using the ceramic filter is lost. Because.

The filtration area / volume ratio of the ceramic filter is 100 to 30 when the concentration and density of dust are high.
It is more preferably 0, and more preferably 200 to 400 when the concentration and density of the dust are low. Here, the “filtration area / volume ratio” is a value obtained by dividing the total area (m ² ) of the filtration walls of the cells constituting the ceramic filter by the volume (m ³ ) of the ceramic filter, that is, the effective volume per unit volume. It is a filtration area.

The backwashing of the ceramic filter is 30 to 36.
It is preferably performed at 0-minute intervals, but preferably performed at intervals of 30 to 120 minutes when the concentration and density of dust are high, and performed at intervals of 90 to 360 minutes when the density and density of dust are low. preferable. If the interval is less than 30 minutes, it is difficult to effectively remove harmful substances because the contact time between the filtration surface and the reactant is not sufficient.
If the interval is longer than 360 minutes, dust is excessively accumulated in the pores of the inner wall of the cell, which may increase the pressure loss or block the cell.

In the present invention, the removal of harmful substances from the exhaust gas of the incinerator is performed by spraying the reactant upstream of a predetermined distance from the ceramic filter. This is to ensure a sufficient time for the reaction to reach. That is, if the removal of harmful substances is mainly performed in the bag filter as in the case of the bag filter, it is necessary to retain a large amount of dust coated with the reactant on the inner wall of the cell in order to perform effective removal. However, since the pressure loss of the filter becomes large, the present invention is designed to remove harmful substances before the exhaust gas from the incinerator reaches the ceramic filter.

The spray of the reactant is preferably performed at an upstream of 1.5 m or more from the ceramic filter, more preferably at a position of 5 m or more, and more preferably at a position of 5 m or more.
It is more preferable to perform the measurement at a position separated by 0 m or more. 1.
If the distance is shorter than 5 m, sufficient time for the reaction cannot be secured. When a sufficient distance cannot be secured, it is preferable to provide a reaction tower and reduce the gas flow rate to extend the reaction time.

In the present invention, one or two or more agents selected from the group consisting of a desalinating agent, a denitrifying agent, a desulfurizing agent, a de-dioxin agent and a heavy metal agent can be used as the reactant. Specifically, slaked lime, calcium carbonate, dolomite and the like are preferably used as desalting agents and desulfurizing agents, ammonia and the like are used as denitrifying agents, activated carbon is used as a deoxidizing agent, and decarbonizing agents are activated carbon and the like. Moreover, it is not particularly limited to the nature of the reactants, liquid, powder, gas, although those of slurry or the like is used, HCl in the exhaust gas, from the viewpoint reactivity with SO _x is slurry Is preferred.

Further, in the present invention, in order to reuse the unreacted reactant in the dust, the dust is blown off by a backwashing device, and the collected dust is fed upstream of the ceramic filter and recirculated. preferable.

The ceramic filter used in the present invention generally includes a ceramic filter including a honeycomb filter having a plurality of cells. In the present invention, a honeycomb filter is defined as shown in FIG. ,
This refers to a filter having a large number of cells 1 separated by partition walls 2.

A ceramic filter having no honeycomb structure refers to a multilayer filter as shown in FIG.

By collecting dust from an incinerator exhaust gas using the dust collecting apparatus or the dust collecting method of the present invention, the same dust collecting performance and harmfulness as the bag filter can be obtained without increasing the pressure loss using a ceramic filter. Material removal performance can be achieved. Also, the ceramic filter has heat resistance,
In addition, for the same filtration performance, it is smaller than the bag filter, so if it is used for collecting exhaust gas from incinerators, the dust collector itself can be made compact, and it can be used at high temperatures, and the exhaust energy can be reduced. Effective utilization can be achieved.

[0024]

Hereinafter, the present invention will be described in more detail with reference to the illustrated embodiments, but the present invention is not limited to these embodiments.

(Example 1) A honeycomb filter having a square end face of 150 mm on a side and a length of 500 mm was prepared by using four honeycomb filters.
Dust collection of incinerator exhaust gas using the provided dust collector,
The state of clogging of the filter and the desalination of the gas to be treated were examined. As shown in FIG. 1 (a), the dust collector used was equipped with a backwashing device and a reactant spray device 3 m upstream of the honeycomb filter. Each of the honeycomb filters used had a cross section of approximately 70 mm having a square shape of 4 mm on a side.
It had zero cells and the filtration area / volume ratio was 400. Also, a honeycomb filter that can withstand high temperature conditions up to 900 ° C. was used. The filtration flow rate of the incinerator exhaust gas sent from the incinerator to the dust collector was set at 1 m / min, and the backwash was performed at 30 minute intervals. Powdered slaked lime was used as the reactant, and the spraying conditions were 2 g / m ³ .

The condition of clogging of the filter was examined by pressure loss. That is, the incinerator gas was introduced into the honeycomb filter at a constant filtration flow rate, the backwashing conditions were adjusted, continuous operation was performed, and the pressure loss before and after the filter was measured. Based on the measurement results, the degree of clogging was evaluated based on the following criteria. The pressure loss recovered before and after backwashing, and the pressure loss was stable for a long period of time. ○ ○ The pressure loss did not recover before and after backwashing, and the pressure loss increased.

The desalting property of the gas to be treated was measured by measuring the HCl concentration after the honeycomb filter and evaluated according to the following criteria. The HCl concentration after the honeycomb filter is less than 50 ppm ... ○ The HCl concentration after the honeycomb filter is 50 ppm or more ... ×

Table 1 shows the results and various characteristic values of the used dust collector. Table 1 also shows the size, filtration area / volume ratio, and heat resistance of a general bag filter used in a dust collector for incinerator exhaust gas (Reference Examples 1 and 2).

(Examples 2 and 3) In Example 2, the filtration area / volume ratio of the filter was set to 200 by using a honeycomb filter having approximately 300 cells each having a square cross section of 6 mm on a side. Except for the point, in Example 3, a filter having a filtration area / volume ratio of 100 was used by using a honeycomb filter having approximately 100 cells having a square cross section of 10 mm on a side. ,
The incinerator exhaust gas was collected under the same conditions as in Example 1,
Check the condition of filter clogging and the desalination of the gas to be treated.
Investigation was performed in the same manner as in Example 1.

Table 1 shows the results and various characteristic values of the used dust collector.

Comparative Examples 1 and 2 In Comparative Example 1, a filter having a filtration area / volume ratio of 2000 was used by using a honeycomb filter having about 10,000 cells having a square cross section of 1 mm on a side and having about 10,000 cells. Except for the point, in Comparative Example 2, by using a honeycomb filter having about 2000 cells having a square cross section of 2 mm on a side,
Exhaust gas from the incinerator was collected under the same conditions as in Example 1 except that the filtration area / volume ratio of the filter was set to 1000, and the state of clogging of the filter and the desalination of the gas to be treated were determined. And in the same manner as in Example 1.

Table 1 shows the results and various characteristic values of the used dust collector.

[0033]

[Table 1]

(Example 4) A honeycomb filter having a square end face of 150 mm on a side and a length of 500 mm was used.
Dust collection of incinerator exhaust gas using the provided dust collector,
The state of clogging of the filter and the desalination of the gas to be treated were examined. As shown in FIG. 1, the dust collector used was equipped with a backwashing device and a reactant spray device arranged 3 m upstream from the honeycomb filter. Each of the honeycomb filters used had approximately 300 cells having a square cross section of 6 mm on a side, and the filtration area / volume ratio was 200. Also, a honeycomb filter that can withstand high temperature conditions up to 900 ° C. was used. The flow rate of the incinerator exhaust gas sent from the incinerator to the dust collector was set at 1 m / min, and the backwash was performed at intervals of 30 minutes. Also, powdered slaked lime is used as the reactant,
The spray condition was 2 g / m ³ . The clogging state of the filter and the desalting property of the gas to be treated were examined in the same manner as in Example 1. Table 2 shows the results and various characteristic values of the used dust collector.

Examples 5 to 10 The same conditions as in Example 4 except that the backwashing time interval and the degree to which the reactant spray device is arranged upstream of the filter were appropriately changed. The incinerator exhaust gas was collected at, and the state of clogging of the filter and the desalting property of the gas to be treated were examined in the same manner as in Example 1. Table 2 shows the results and various characteristic values of the used dust collector.

Example 11 Exhaust gas from an incinerator was collected under the same conditions as in Example 1 except that a slurry prepared by mixing slaked lime powder with water was used as a reactant. The state of clogging of the filter and the desalting property of the gas to be treated were examined in the same manner as in Example 1. Table 2 shows the results and various characteristic values of the used dust collector.

(Example 12) As shown in FIG. 1 (b), except that a collected dust recirculation device was installed, and dust collected by a backwashing device was introduced upstream of a ceramic filter. Then, dust from the incinerator exhaust gas was collected under the same conditions as in Example 1, and the state of clogging of the filter and the desalting property of the gas to be treated were examined in the same manner as in Example 1.
In addition, the condition of the recycle of the collected dust was 1 g / m ³ . Table 2 shows the results and various characteristic values of the used dust collector.

(Comparative Examples 3 to 6) The same conditions as in Example 4 were adopted except that the values of the time interval for backwashing and the degree to which the reactant spray device was arranged upstream of the filter were appropriately changed. The incinerator exhaust gas was collected at, and the state of clogging of the filter and the desalting property of the gas to be treated were examined in the same manner as in Example 1. Table 2 shows the results and various characteristic values of the used dust collector.

[0039]

[Table 2]

From Table 1, it can be seen that the dust collector of the embodiment having a filtration area / volume ratio of 400 or less does not cause clogging of partition walls or blockage of cells, while the comparative example having a filtration area / volume ratio of more than 400. It can be seen that in the dust collector of the above, clogging of the partition wall and blockage of the cell occur, leading to an increase in pressure loss.

Further, from Table 2, in the dust collector of the embodiment in which the backwashing interval is 360 minutes or less, the clogging of the partition walls and the blockage of the cell do not occur, whereas the backwashing interval is 360 minutes. It can be seen that in the dust collectors of Comparative Examples 4 and 5, in which the partition walls are clogged and the cells are blocked, which leads to an increase in pressure loss.

In addition, the reactant spraying device is moved from the filter to 1.
In the dust collector of the embodiment which is arranged 5 m or more upstream and the backwashing interval is 30 minutes or more, while the desalting property is good,
It can be seen that the dust collector of Comparative Example 1 in which the backwashing interval is less than 30 minutes and the dust collector of Comparative Example 6 in which the position of the reactant spraying device is less than 1.5 m from the filter is poor in desalination. .

Further, in the dust collecting apparatus of Example 11 in which the slurry-like reactant was sprayed and in the dust collecting apparatus of Example 12 in which the collected dust was recirculated, the dust collecting apparatus of Example 4 in which other conditions were the same. The desalting property was better than the apparatus.

[0044]

[Effects of the Invention] By collecting dust from an incinerator exhaust gas by the dust collecting apparatus or the dust collecting method of the present invention, the dust collecting performance is almost the same as that of the bag filter without increasing the pressure loss by using a ceramic filter. And toxic substance removal performance can be achieved. In addition, the ceramic filter has heat resistance, and in the case of the same filtration performance, it is smaller than the bag filter, so if used for dust collection of incinerator exhaust gas,
The dust collecting device itself can be made compact, and can be used at high temperatures, so that the exhaust energy can be effectively used.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram showing (a) an example and (b) another example of an incinerator exhaust gas dust collecting apparatus of the present invention.

FIG. 2A is a perspective view illustrating an example of a multilayer filter,
(B) is a front view and (c) is a side view.

FIG. 3 is a schematic diagram illustrating an example of a honeycomb filter.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Cell, 2 ... Partition, 3 ... Honeycomb filter, 4 ... Ceramic filter, 5 ... Dust collector, 6 ... Hole.

 ──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Yasushi Kondo 2-56, Suda-cho, Mizuho-ku, Nagoya-shi, Aichi Japan F Co., Ltd. F term (reference) 4D058 JA32 JB06 MA15 QA01 QA30 SA20 TA01

Claims (14)

[Claims] 1. A dust collector for incinerator exhaust gas comprising a ceramic filter having a plurality of cells, comprising: a backwashing device for backwashing the ceramic filter; and a reactant upstream of the ceramic filter. A spray device, wherein the filtration area / volume ratio of the ceramic filter is 100 to 4;
A dust collector for incinerator exhaust gas, wherein the exhaust gas is 00. 2. The dust collector for incinerator exhaust gas according to claim 1, wherein the reactant spraying device is installed at least 1.5 m upstream from the ceramic filter. 3. The backwashing of the ceramic filter is performed for 30 to 3 times.
The dust collector for incinerator exhaust gas according to claim 1 or 2, wherein the dust collection is performed at intervals of 60 minutes. 4. The dust collection device for incinerator exhaust gas according to claim 1, further comprising a collected dust recirculation device for feeding dust collected by the backwashing device upstream of the ceramic filter. 5. The method according to claim 1, wherein the reactant is one or more agents selected from the group consisting of a desalinating agent, a denitrifying agent, a desulfurizing agent, a dedioxinous agent and a heavy metal agent. 4
2. A dust collector for incinerator exhaust gas according to claim 1. 6. The dust collector for incinerator exhaust gas according to claim 1, wherein the reactant spraying device sprays a slurry-like reactant. 7. The dust collector for incinerator exhaust gas according to claim 1, wherein the ceramic filter is a honeycomb filter. 8. A method for collecting exhaust gas from an incinerator using a ceramic filter having a plurality of cells, wherein the filtration area / volume ratio of the ceramic filter is 100 to 4%.
00. A method for collecting exhaust gas from incinerator exhaust gas, comprising removing harmful substances from the exhaust gas by spraying a reactant upstream of the ceramic filter, and performing back washing of the ceramic filter. 9. The method for collecting exhaust gas from an incinerator according to claim 8, wherein the spraying of the reactant is performed at least 1.5 m upstream from the ceramic filter. 10. The backwashing of the ceramic filter is performed for 30 to 30 minutes.
The method for collecting exhaust gas from an incinerator according to claim 8, wherein the method is performed at intervals of 360 minutes. 11. The method for collecting exhaust gas from an incinerator according to claim 8, 9 or 10, wherein the dust collected by the backwashing device is introduced upstream of the ceramic filter and recirculated. 12. The method for collecting exhaust gas from an incinerator according to claim 8, wherein the slurry-type reactant is sprayed. 13. The method according to claim 13, wherein the reactant is a desalinating agent, a denitrifying agent, a desulfurizing agent,
10. The method according to claim 8, wherein the agent is one or more agents selected from the group consisting of a de-dioxin agent and a de-heavy metal agent.
13. The method for collecting exhaust gas from an incinerator according to 11 or 12. 14. The method for collecting exhaust gas from an incinerator according to claim 8, wherein the ceramic filter is a honeycomb filter.