JP3491124B2 - Filtration type dust collector - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a filter type dust collecting apparatus for removing harmful substances in exhaust gas from an municipal waste incineration facility, and more particularly to an urban incinerator facility, a combustible waste treatment facility and other combustion facilities. This is a device that detoxifies the exhaust gas discharged from the equipment and the harmful substances in the exhaust gas discharged from the metal refining factories during the heating process.Organic halogens such as dioxins in the exhaust gas using a powder adsorbent. The present invention relates to a filtration dust collector for removing compounds.

[0002]

2. Description of the Related Art In recent years, atmospheric emission of highly toxic dioxins generated from municipal waste incineration facilities has become a social problem. In Japan, we have set guidelines for prevention of dioxins generation, etc. to suppress the generation of dioxins contained in exhaust gas discharged from refuse incinerators, etc., and there is a tendency to further tighten regulations from the danger.

Exhaust gas discharged during the process of incinerating municipal solid waste or industrial waste, or when preheating and melting a scrub containing flammable deposits in a metal smelting plant, etc., contains acid such as soot and hydrogen chloride. It contains various harmful substances such as gases, nitrogen oxides, heavy metals such as mercury, and organic halogen compounds such as dioxins and their precursors.

Among these harmful substances, a method of removing dust and acid gas by a filter type dust collecting apparatus such as a bag filter by spraying a basic absorbent such as slaked lime has been widely used in recent years. FIG. 3 shows a conventional bug filter, and a method of removing the bug filter will be described. A neutralizing agent supply flue 26 is provided in the upstream flue 24 of the bag filter main body 21, and slaked lime is sprayed from the neutralizing agent supply flue 26 into the upstream flue 24 to provide the bag filter filter cloth 2
On the surface of No. 2, a deposit layer with dust and slaked lime is formed. Then, in a process in which the exhaust gas passes through the filter cloth 22, an acidic component in the exhaust gas is removed by a neutralization reaction, and at the same time, dust and dirt in the exhaust gas are collected and removed. In the figure, 23 is a dust discharge hopper, 25 is an exhaust gas inlet, and 27 is an exhaust gas discharge duct.

On the other hand, as a method for reducing the organic halogen compounds such as dioxins in the exhaust gas, the following method can be mentioned. Explaining one of them with reference to FIG. 4, the exhaust gas from the incinerator is introduced into the filtration dust collector 13 through the boiler 11 that recovers heat and the temperature reducing tower 12 that cools the exhaust gas, The soot and dust are removed by the filter type dust collector 13, and the exhaust gas that has passed through the catalyst tower 14 is discharged from the chimney 15. In this way, the dioxin in the exhaust gas is removed by installing the catalyst tower 14 filled with the dioxin oxidation catalyst in the latter stage of the filtration dust collector 13. It should be noted that an induction fan for guiding the exhaust gas, a slaked lime supply device for removing the acid gas, and the like are omitted for simplicity.

The other is the method disclosed in Japanese Unexamined Patent Publication No. 5-131323, and as shown in FIG. 5, a powdery activated carbon spraying section 16 and a base are provided between the boiler 11 and the filtration collecting apparatus 13. Is a method of removing the dioxins in the exhaust gas by providing the absorbent absorbent spraying section 17 and blowing a powder adsorbent such as powdered activated carbon into the flue upstream of the dust collector.
Specifically, as shown in FIG. 6, the temperature reducing tower 12
From the powder adsorbent supply device 19 to the dehumidifying inlet side flue or the dehumidifying output side flue of the adsorbent conveying tubes 18a, 18b.
It is a method for removing harmful substances by supplying an adsorbent such as powdered activated carbon from any of the above.

[0007]

However, in the exhaust gas incineration processing flow of FIG. 4, the catalyst is often expensive, for example, the dioxin oxidation catalyst in the catalyst tower 14 is a titania-based catalyst supporting a noble metal. That
Even if the cost is low, it is necessary to newly install the catalyst tower 14 at the subsequent stage of the dust collector 13, which has a disadvantage of increasing the equipment cost.

Further, in the exhaust gas incineration processing flow of FIG.
The adsorbent is sprayed on the flue upstream of the dust collector 13. For example, as shown in FIG. 6, when the adsorbent is blown from the adsorbent transport tube 18a to the inlet of the temperature reducing tower, the gas flow velocity in the temperature reducing tower 12 is greatly reduced, and the adsorbent drops due to its own weight. However, there is a drawback that the proportion of the adsorbent, which is unreacted and discharged to the outside of the system, is wasted without contributing to the removal of dioxins.

When the adsorbent is blown into the exhaust gas introduction duct at the entrance of the dust collector from the adsorbent transport tube 18b without blowing the adsorbent into the inlet duct of the temperature reducing tower 12, one of the blown adsorbents Due to the low gas flow rate in the dust collector, the part falls into the dust discharge hopper by its own weight without being collected by the filter cloth, and the adsorbent remains unreacted without affecting the removal of dioxins. It has the drawback that it is discharged outside and is wasted.

In other words, lowering the adsorbent collection rate on the filter cloth means lowering the efficiency of removing organic halogen compounds such as dioxins due to the adsorption reaction. Further, in order to secure a certain level of detoxification rate, it is necessary to increase the amount of adsorbent blown in, which has a drawback of increasing the cost of detoxification treatment of exhaust gas.

The present invention has been made in view of the above problems, and it is possible to efficiently and efficiently perform organic halogen compounds such as dioxins without newly installing a removing device such as a catalyst tower for removing dioxins in exhaust gas. The present invention provides a filter-type dust collector capable of removing the above.

[0012]

SUMMARY OF THE INVENTION The present invention has achieved the above object by focusing on the following points. The present inventors have found that about 10 to 30% of the weight of the adsorbent blown into the conventional filter-type dust collector shown in FIG. 5 (FIG. 6) is not collected by the filter cloth but is discharged by its own weight. We examined the problem of falling into the hopper. As a result, filtration dust collector 1
When the exhaust gas is introduced into the dust collection chamber through the exhaust gas inlet provided on the side wall of the main body of No. 3, the exhaust gas flow velocity rapidly decreases (usually decreases to about 1/10 to 1/30),
The powder adsorbent has a particle size distribution, and it is difficult for powder adsorbent with a large particle size to be carried along the gas flow.In the vicinity of the dust discharge hopper below the dust collection chamber, there is an extremely small gas flow area or a stagnation flow area. The powder passing through this area is difficult to be carried by the gas flow due to the particle size,
Was confirmed by an experiment. Due to such an event, it was concluded that about 10 to 30% of the weight of the adsorbent falls to the dust discharge hopper under the dust collector due to gravity before reaching the filter cloth. As the adsorbent, powdered activated carbon was used.

First, the invention of claim 1 is a filtration type dust collecting apparatus for removing an organic halogen compound in exhaust gas by spraying a powder adsorbent on the exhaust gas discharged by combustion or heating. The dust collecting chamber of the main body of the filter type dust collector has a cylindrical shape, an exhaust gas inlet is provided in the lower part of the main body of the filter type dust collecting device, and a clean exhaust gas duct is installed in the upper part of the dust collecting chamber.
Is, the adsorbent blowing opening for blowing the adsorbent into the dust collecting chamber, from the exhaust gas inlet of the filtration-type dust collector body
Also filtration type dust collector, characterized in that installed in a position lower than the cleaning exhaust gas duct above.

According to the present invention, the dust collecting chamber in the main body of the filtration type dust collecting device has a cylindrical shape, and an extremely small region or stagnation region of the gas flow generated near the corner portion of the conventional rectangular parallelepiped type dust collecting chamber (this is There is no low velocity region of the exhaust gas flow).
For this reason, the adsorbent blown into the dust collection chamber is efficiently transported along the gas flow, so that the adsorbent is less likely to drop into the dust discharge hopper located at the lower part of the dust collection chamber, and the adsorbent on the filter cloth is prevented. The adsorbent collection rate increases. Next, since the low flow velocity region of the exhaust gas flow does not exist, the temperature distribution in the dust collection chamber is made sufficiently uniform, and the low temperature region generated near the corner of the conventional rectangular parallelepiped dust collection chamber does not exist. Therefore, oxidative corrosion of the side wall near the corners of the dust collection chamber does not occur when there is a low temperature region, and dust in the exhaust gas may aggregate or accumulate due to low temperature and low flow rate. can avoid.

Further, the adsorbent inlet and the exhaust gas inlet are installed separately, and the adsorbent inlet is connected to the main body of the filter type dust collector.
Than the cleaning exhaust gas duct in the above the gas inlet port
Since the adsorbent is also placed below , the retention time in the dust collection chamber from when the adsorbent is blown into the dust collection chamber until it falls into the dust discharge hopper increases, increasing the chances of being collected on the filter cloth. The adsorbent is efficiently collected on the surface of the filter cloth. In addition, when the residence time of the adsorbent increases, the exhaust gas flow from the exhaust gas inlet installed below the adsorbent inlet (usually,
The clean exhaust gas after passing through the filter cloth is collected in the clean exhaust gas duct installed in the upper part of the dust collection chamber. For this reason, the exhaust gas flow in the dust collection chamber becomes an upward flow), so that upward energy is given to the adsorbent, and the adsorbent is dispersed over a wider area and spreads over the filter cloth in the entire dust collector. To be collected. In this way, since the adsorbent is efficiently collected on the filter cloth, when the exhaust gas passes through the dust accumulation layer on the surface of the filter cloth,
Organic halogen compounds such as dioxins in exhaust gas are
Efficiently removed by adsorption. In other words, if an equivalent detoxification rate is sought, the effect of reducing the amount of adsorbent blown can be obtained.

A second aspect of the present invention is the filtration type dust collecting apparatus according to the first aspect, wherein a plurality of the adsorbent blowing ports are provided. According to the present invention, when two or more adsorbent inlets are installed, the effect of dispersing the adsorbent on the filter cloth in the dust collecting chamber is more effectively achieved, and the adsorbent is more uniformly collected over a wide area. Collected on the filter cloth in the entire costume,
Organic halogen compounds such as dioxins in exhaust gas can be adsorbed and removed more efficiently.

Further, the invention of claim 3 is characterized in that the blowing direction of the powder adsorbent blown from the adsorbent blowing port is substantially parallel to the tangential direction of the inner wall circumference of the dust collecting chamber. It is the filtration dust collector according to 1 or 2. According to the present invention, when the adsorbent is blown together with the carrier air from the adsorbent blowing duct that is installed substantially parallel to the tangential direction of the circumference of the inner wall of the dust collecting chamber, the carrier air flow containing the adsorbent is generated. A swirling flow is formed by swirling along. Swirl flow
Initially, it circulates around the inner wall of the dust collection chamber, but since the exhaust gas is sucked through the filter cloth, the swirling flow disappears toward the center of the dust collection chamber. That is, the adsorbent conveyed to the swirling Ryu is first collected on the filter cloth outside the dust collection chamber, but since the swirling flow is directed toward the center of the dust collection chamber, the adsorbent collects dust in this process. The filter cloth located in the center of the chamber spreads, and as a result, the adsorbent is collected on the filter cloth in the entire dust collection chamber. Further, when a swirl flow occurs, the adsorbent transported by the swirl flow passes near many filter cloths, and therefore the adsorbent that passes near the filter cloth is affected by the exhaust gas suction effect of the filter cloth. It is separated from the swirling flow, has less drop loss, and is more effectively collected on the filter cloth. In this way, the adsorbent is efficiently and uniformly collected on the filter cloth, so that the effect described in the first aspect of the invention can be obtained to the same or better level.

Further, in the invention of claim 4, the amount of carrier air for blowing the powder adsorbent into the dust collecting chamber is set to 1/100 to 1/5 of the total amount of exhaust gas treated, and the blowing and discharging speed is 10.
It is set to -30 m / s, It is a filtration type dust collector of Claim 1, 2 or 3. In this invention,
A swirl flow was generated by the adsorbent carrier air, but if the swirl flow is too strong, that is, if the swirl flow rate and discharge speed are too high, it accumulates on the filter cloth located near the adsorbent inlet. The dust accumulation layer is blown away by a strong swirling flow and destroyed, or the adsorbent is separated from the swirling flow due to inertial force and collides with the dust collection chamber inner wall and falls or accumulates on the inner wall without reaching the filter cloth. Alternatively, the swirling flow of normal-temperature air cools the filter cloth, and the reaction products in the dust accumulation layer cause deliquescent, which increases the risk of clogging the filter cloth. In order to avoid this danger, it is necessary to specify the strength of the swirling flow. That is, the amount of carrier air for blowing the adsorbent is set to 1 of the total exhaust gas treatment amount.
/ 100 to ⅕, and blow discharge speed 10 to 30 m / s
By setting the above, it is possible to give a swirling flow of appropriate strength. The amount of carrier air for blowing the adsorbent, that is, the amount of air that causes a swirling flow is 1/1 of the exhaust gas treatment amount.
When it is set to be 0 to 1/5 and the blowing discharge speed is 10 m / s or less, the swirling flow becomes weak, and the effect of efficiently dispersing the adsorbent by the swirling flow becomes very small, and the advantage of generating the swirling flow is obtained. It is not preferable because it disappears.

Further, the carrying air amount is 1/5 or more, or
If the blowing and discharging speed is 30 m / s or more, there is a risk of blowing away the dust accumulation layer accumulated on the filter cloth, a risk that the adsorbent will be separated from the swirling flow due to inertial force, and will not be collected on the filter cloth. It is not preferable because there is a risk of deliquescent generation of the dust accumulation layer. Therefore, if the amount of carrier air and the blow-in / discharge speed of carrier air are set within the range described in the invention of claim 4, the adsorbent contained in the general-purpose air (swirl flow) will be filtered out near the inner wall of the dust collection chamber. From the cloth to the filter cloth in the center of the dust collection chamber, it is evenly distributed over a wider area, and the effect of being collected on the filter cloth in the entire dust collection chamber can be more reliably obtained. In this way, since the adsorbent is efficiently and uniformly collected on the filter cloth,
The function of adsorbing and removing an organic halogen compound such as dioxins can be reliably obtained by the above invention.

The invention of claim 5 is characterized in that a carbon-based porous powder having a specific surface area of 100 m ² / g or more is used as the powder adsorbent. The filtration type dust collector described in 1. In the present invention, carbon-based porous powder such as activated carbon powder is used as the adsorbent. Carbon-based porous powders such as powdered charcoal have a large specific surface area and generally have a large adsorption effect. And since it is carbon-based, it is particularly effective in adsorbing organic halogen compounds and mercury such as the highly toxic dioxins contained in the exhaust gas, so by blowing it into the filter dust collector, the dioxin contained in the exhaust gas It is possible to efficiently remove the organic halogen compounds such as the compounds and mercury. When this adsorbent has a specific surface area of 100 m ² / g or less when adsorbing and removing organic halogen compounds such as dioxins, a sufficient detoxification rate cannot be obtained because the adsorption performance is small. In other words, in order to achieve a predetermined detoxification rate, the adsorbent is consumed more than necessary, resulting in a problem that the cost increases and a problem that causes an increase in the pressure loss of the filter cloth. Therefore, the specific surface area of the adsorbent is 1
It is preferably 00 m ² / g or more.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of a filtration type dust collecting apparatus according to the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing an embodiment of a filtration type dust collecting apparatus of the present invention. The figure (a) is the perspective view, and the figure (b) is the principal part sectional drawing. In the figure (a), 1 is a filter type dust collector main body, 2 is a filter cloth, 3 is a dust discharge hopper, 4 is an exhaust gas introduction duct, 5 is an exhaust gas introduction slot, 6 is an adsorbent blowing duct, 7 is an adsorbent blowing B, 8 is an exhaust gas discharge duct, 9
Is a dust discharging device. It should be noted that the dust removing device and the like attached to the filtration type dust collecting device are not shown. The arrangement of the filter cloth 2 is shown in FIG.

The filter-type dust collector main body 1 has a cylindrical inner peripheral surface, an exhaust gas introduction port 5 is provided at the lower part of the side wall of the filter-type dust collector main body 1, and an adsorbent blowing port 7 is provided above it. It is provided. The exhaust gas introducing duct 4 and the adsorbent blowing duct 6 are connected to the exhaust gas introducing rod 5 and the adsorbent blowing port 7, respectively, and communicate with the inside of the main body (dust collecting chamber) of the filter type dust collecting apparatus.
On the upstream side of the exhaust gas introduction duct 4, for example, as shown in FIG. 4 of the related art, a boiler 11 for recovering heat,
A temperature reducing tower 12 for adjusting the temperature of the exhaust gas is arranged, and the exhaust gas containing an organic halogen compound such as dioxins discharged from the incinerator or the like is filtered through the exhaust gas introduction duct 4 after passing through these devices. Introduced to the dust collector. A slender cylindrical filter cloth 2 is suspended in the filtration type dust collector main body 1 in a regularly arranged manner from the uppermost part of the dust collecting chamber. Two adsorbent inlets 7 are provided, and the adsorbent blowing duct 6 is connected to each of them.

As the adsorbent, powdered activated carbon or the like is used, which is conveyed by air from an adsorbent supply device (not shown) and blown into the filter type dust collecting device through the adsorbent blowing duct 6 and the adsorbent blowing port 7. . The blown adsorbent is introduced into the dust collection chamber inside the filter-type dust collector main body 1, reaches the surface of the filter cloth 2, and is accumulated and maintained on the surface of the filter cloth 2 until it is removed.

The exhaust gas flowing into the filter type smoke collector is
The organic halogen compounds such as dioxins in the exhaust gas are removed from the exhaust gas by the adsorbing action of the adsorbent in the process of passing through the deposited layer containing the adsorbent on the surface of the filter cloth 2 and filtering and collecting dust. On the other hand, dust such as dust and adsorbent accumulated on the surface of the filter cloth by the filter dust collecting action of the filter cloth 2 is removed at an appropriate dust removal interval, and the dust is discharged by the dust discharge device 9 via the dust discharge hopper 3. It is discharged outside the system. Filter cloth 2
The clean exhaust gas that has passed through is discharged to the atmosphere from the exhaust gas discharge duct 8.

On the other hand, two adsorbent introduction ducts 6 are connected to the upper portion of the side wall (simply referred to as the side wall of the apparatus) of the cylindrical filter type dust collecting apparatus main body 1 at a substantially right angle toward the center of the dust collecting chamber. There is. On the upstream side of the adsorbent blowing duct 6, an adsorbent supply device (not shown) including a silo that stores the adsorbent, a device that cuts out the adsorbent, and a device that conveys the adsorbent by a blower is provided, The adsorbent is carried by the carrier air and is blown into the dust collecting chamber from the adsorbent blowing roller 7. The position of the adsorbent blowing roller 7 is preferably a position above the exhaust gas introducing roller 5, and is most preferably installed at a position close to the top of the dust collecting chamber. When the filter cloth 2 is installed above as described above, the amount of the adsorbent collected on the filter cloth 2 increases, and the proportion of the unreacted material that falls and is discharged decreases.

If two or more adsorbent inlets are installed, the effect of dispersing the adsorbent on the filter cloth in the collecting chamber is more effectively exerted, and the adsorbent is more uniformly spread over a wide area. Collected on the entire filter cloth in the dust collector. Specifically, the number of adsorbent blowing ports may be set in consideration of the scale of the filtration type dust collector set from the treated exhaust gas amount. For example, when the treated exhaust gas amount exceeds 20,000 Nm ² / h. About 4 is good for.

At the position of the exhaust gas inlet 4, the amount of dust collected on the filter cloth 2 having a relatively large particle size, which should be directly collected without being collected by the filter cloth 2 and should be collected, is reduced. Therefore, in order not to increase the pressure loss of the filter cloth 2, it is desirable that the position is lower than the center of the filter cloth 2 in the longitudinal direction, but the installation position of the exhaust gas inlet is not particularly limited. The cone-shaped dust discharging hopper 3 may have an inclination angle satisfying a repose angle peculiar to the dust to be collected, and an auxiliary discharging means such as a vibrator may be installed if necessary. The dust discharging device 8 may be any device that can discharge the dust temporarily accumulated in the conical dust discharging hopper, and for example, a double flap damper or a rotary valve is used.

Next, another embodiment of the present invention will be described with reference to FIG. FIG. 3A is a cross-sectional view of a main part, and shows a filtration type dust collecting device in which the direction of the adsorbent blown from the adsorbent blower 7 is made parallel to the tangential direction of the circumference of the dust collecting chamber inner wall. . FIG. 2B is a side view of the filtration type dust collector. In the embodiment shown in the figure, two adsorbent blowing ports are generally placed.

As shown in FIG. 3A, the adsorbent blowing duct 6 is installed parallel to the tangential direction of the circumference of the inner wall of the dust collecting chamber. Is blown into the dust collection chamber. Therefore, the carrier air flow containing the adsorbent swirls along the circumference of the inner wall of the dust collecting chamber to form a swirling flow. The swirl flow first swirls the inner wall of the dust collection chamber, but since the exhaust gas is sucked through the filter cloth, the swirl flow disappears toward the center of the dust collection chamber. That is,
The adsorbent conveyed in the swirl flow is first collected by the filter cloth outside the dust collection chamber, but since the swirl flow moves toward the center of the dust collection chamber, the adsorbent is collected in the dust collection chamber center in this process. As a result, the adsorbent is collected on the filter cloth in the entire dust collecting chamber. Further, when a swirl flow is generated, the adsorbent conveyed by the swirl flow passes through many filter cloths 2 in the vicinity, and therefore, the adsorbent that passes in the vicinity of the filter cloth 2 is absorbed by the exhaust gas of the filter cloth. Due to the effect, it is separated from the swirling flow, is less likely to fall, and is more effectively collected on the filter cloth.

Here, it is desirable that the swirling flow has an appropriate strength. That is, the amount of carrier air for blowing the adsorbent is 1/100 to 1/5 of the total exhaust gas treatment amount.
By setting the blowing and discharging speed to 10 to 30 m / s, a swirling flow having an appropriate strength can be given. If the amount of carrier air for blowing the adsorbent, that is, the amount of air that produces the swirling flow is 1/100 or less of the exhaust gas-treated star, or if the blowing discharge speed is 10 m / s or less, the swirling flow becomes weak and the swirling flow As a result, the effect of efficiently dispersing the adsorbent becomes extremely small, and the advantage of generating the swirling flow disappears, which is not preferable. When the amount of carrier air is 1/5 or more, or the blowing and discharging speed is 30 m / s or more,
There is a risk of blowing away the dust accumulation layer accumulated on the filter cloth, a risk that the adsorbent is separated from the swirling flow due to inertial force and not collected on the filter cloth, and a risk of deliquescent generation of the dust accumulation layer due to room temperature air. It is not preferable because it occurs. Therefore,
By setting the amount of carrier air and the blowing and discharging speed of carrier air within the above range, the adsorbent contained in carrier air (swirl flow)
From the filter cloth in the vicinity of the dust collection chamber wall to the filter cloth in the center of the dust collection chamber, the particles are evenly distributed over a wider area, and the action of being collected by the filter cloth in the entire dust collection chamber can be more reliably obtained. .

The means for setting the swirling strength of the swirling flow varies depending on the scale of the filtering and dust collecting apparatus and the amount of air to be conveyed, but when the blowing and discharging speed is low, even if the tip of the adsorbent blowing roller 7 is made thin. You may install a guide vane etc. If the amount of carrier air for generating the swirl flow is small, the amount of carrier air may be increased by increasing the capacity of the blower or the compressor. However, if the swirling flow is too strong, as described above, the dust accumulation layer accumulated on the filter cloth is blown away and destroyed, resulting in a problem that an effective adsorption reaction does not occur on the surface of the filter cloth. Therefore, it is also necessary to prevent the swirling flow from becoming extremely strong. Therefore, the adsorbent blowing duct 6 is arranged so that the air carrying the adsorbent swirls along the inner wall of the dust collecting chamber to reduce the speed and uniformly disperse the adsorbent.

Next, the embodiment of the present invention will be described in more detail.
explain. The adsorbent used in the present invention includes dioxins and the like.
With the ability to adsorb the organic halogen compounds of
Any drug may be used as long as it is available. Desirable
Is a carbon-based porous powder, and further, powder
It is more preferable to use the activated charcoal of. Powder packing
If carbon-based porous powder such as carbon is used,
Not only organic halogen compounds such as mercury, but also mercury
Heavy metals can also be removed by adsorption. Powder activated carbon has a specific surface area
Is 1000m²Since it is as large as / g, it has an excellent adsorption effect,
Even if it is peat-based, perilla shell-based, or charcoal-based, the effect is almost the same.
It is the same. If it is a carbon-based porous powder, the specific surface area is
Not as expensive as charcoal, but 100m²/ G or more specific surface area
If so, there is a sufficient adsorption effect, and particle size etc.
Absent. However, the specific surface area is 100m ²/ G or less
Also, due to its low adsorption performance, organic substances such as dioxins
Sufficient detoxification rate of halogen compounds cannot be obtained. Paraphrase
If you want to achieve the specified detoxification rate,
Excessive consumption of adhesive agent, resulting in high cost
And problems that cause increased pressure loss in the filter cloth
Cause Therefore, the specific surface area of the adsorbent is 100 m²/ G
The above is preferable. Also, adsorbent silo storage
Considering safety such as avoiding dust explosion in
Manufactured in the process of fully volatilizing volatiles
It is preferable that the ignition point is sufficiently high.

As a method of blowing the adsorbent into the filtration type dust collecting apparatus through the adsorbent introducing duct 6, the powder is cut out by using a quantitative feeder capable of quantitatively supplying the adsorbent, and the powder is blown by a blower or a compressor. The method of carrying by air is common. Desirably, it is possible to easily control the amount of powder cut out without changing the number of revolutions of the rotating body of the powder supply portion, and to quantitatively supply the powder. This is preferable because the adsorbent is uniformly dispersed in the type dust collector (dust collecting chamber) and the adsorption effect is enhanced. Further, when the adsorbent is conveyed by air, a basic absorbent such as slaked lime powder for removing acidic components in the exhaust gas is mixed into the adsorbent conveying duct 6 and conveyed into the filtration dust collector. May be. By doing so, the slaked lime powder is also efficiently collected by the filter cloth 2 in the filter type dust collector similarly to the adsorbent, and the effect of further promoting the neutralization reaction of the acid gas and slaked lime is obtained,
In addition, organic halogen compounds such as dioxins are adsorbed and removed.

When the adsorbent is conveyed by air with a blower or a compressor, the amount of air conveyed is often very small compared to the amount of treated exhaust gas. Therefore, the air conveyed at room temperature produces and adheres to the surface of the filter cloth. There is almost no possibility of cooling the existing sodium chloride (an example of a neutralization reaction product) to a deliquescing temperature of 110 ° C or lower. However, when the amount of carrier air is large, for example, 1/10 or more of the amount of exhaust gas,
When the filter cloth 2 is disposed in close proximity to the adsorbent blowing port, the carrier air at room temperature collides with the filter cloth 2 at a high flow rate, and the filter cloth 2 is rapidly cooled to produce the neutralization reaction product. Deliquescence,
The filter cloth 2 may be clogged. This problem causes a swirl flow as shown in FIG. 2 to prevent air from directly impinging on the filter cloth. This can be solved by using air that has been heated to 100 ° C. or higher by heat exchange or the like as carrier air.

In the above-described embodiment, as a device for removing dust such as dust accumulated on the filter cloth (backwashing device), a conventionally known means such as a pulse jet type or a back pressure type is applied. The effect is the same regardless of which method is used, as long as the filter cloth is of a type that is suspended in the dust collection chamber and the blowing flow of the adsorbent reaches the filter cloth directly.

Although the filtration dust collector of the present invention has been described as a device attached to a waste incineration facility, it is an industrial waste product in which organic halogen compounds such as dioxins are generated in the exhaust gas discharged by combustion or heating. Even if the exhaust gas is exhausted from combustible waste such as waste or other combustors in general, or the exhaust gas is exhausted when preheating and melting scrap in a metal refining industry such as an electric furnace, the filtration type collection of the present invention It can be treated with a dust device and the same effect can be obtained.

In the present invention, the organohalogen compound which is removed from the exhaust gas by the adsorbent is referred to as a dioxin and a dioxin precursor or a related substance whose guideline is designated by the Ministry of Health and Welfare as a toxicity conversion value. Chlorobenzene, chlorophenol, P
CB is a general term for these chemical substances partially substituted with halogen elements other than chlorine. Furthermore, dioxins are a general term and a general term for polydibenzoparadioxin and polydibenzofuran, and are often evaluated by their toxic equivalent concentrations.

[0038]

EXAMPLES In order to confirm the effect of the present invention, the comparison results of the exhaust gas treatment test conducted by the filtration type lotus collecting apparatus of the present invention and the conventional example will be described below with reference to Table 1. Table 1
Shows comparative results of Examples 1 and 2 according to the filter type dust collector of the present invention and a conventional filter type dust collector. As the harmful substances, soot, dust, HCl, mercury, chlorophenol (CP), and five types of dioxins are represented, and the removal effects are compared. Of these, the latter two are organic halogen compounds.

Example 1 shows the results of carrying out the filtration type dust collector of FIG. 1 in a refuse incineration treatment facility, and other exhaust gas treatment facilities were tested in the arrangement shown in the exhaust gas treatment flow of FIG. The operating conditions are as follows: boiler outlet exhaust gas temperature 250 ° C,
The inlet temperature of the filtration dust collector, that is, the treatment temperature of 180 ° C., the treatment exhaust gas amount of 40,000 Nm ³ / h, and the powdered activated carbon was used as the adsorbent. Example 2 shows the results of implementing the filter dust collector of FIG. 2 in a refuse incineration facility, and the configuration and operating conditions of the other exhaust gas treatment facilities were the same as in Example 1. In addition, the comparative example is the conventional filtration type dust collector of FIG. 3 and shows the results of the implementation in the refuse incineration treatment facility. The configurations and continuous rotation conditions of the other exhaust gas treatment facilities are the same as those in the two examples. did. In addition, the slaked lime powder sprayed to remove acidic gas such as HCl and SOx is the same as in Example 1,
In both 2 and the comparative example, spraying was performed on the outlet duct of the temperature reducing tower, and the spray amount was the same in both the example and the comparative example.

[0040]

[Table 1]

As is clear from the results shown in Table 1, the soot and dust, and the acidic gas typified by HCl, were subjected to the dust collecting action and the acid gas removing action of the filtration type dust collecting apparatus in Example 1,
2 and Comparative Examples show that the removal was possible at a high level. Further, it was shown that mercury, chlorophenol, and dioxins were obtained in a higher level of removal in the example using the filtration dust collector of the present invention than in the comparative example using the conventional filtration dust collector. ing. That is, the filtration type dust collecting apparatus of the present invention is a rectangular parallelepiped type in which the conventional apparatus blows the adsorbent into the exhaust gas introducing duct, while the adsorbent blowing port is installed at a position above the exhaust gas introducing port, and Since the main body of the device is of a cylindrical type, the collection rate of the adsorbent blown into the filter cloth is high, which indicates that organic halogen compounds such as dioxins can be efficiently removed.

In the present invention, since activated carbon powder, which is a carbon-based porous powder, is used as the adsorbent, not only organic halogen compounds such as chlorophenol and dioxins but also mercury can be efficiently removed. Shows.
Furthermore, in Example 2, since the adsorbent blowing port was installed so that a swirl flow was generated in the dust collection chamber, the collection rate of the adsorbent on the filter cloth was higher than that in Example 1, and dioxins such as dioxins could be collected. It shows that the organic halogen compound can be removed more efficiently. Next, as a result of continuous operation for one week, in the comparative example, dust was slightly accumulated on the four corners of the dust discharge hopper of the filtration type dust collector, but in Example 2 accumulation of dust was observed. Nakatsuta. That is, since it is a cylindrical type, the exhaust gas low flow velocity region in the dust collection chamber is hardly formed, and dust is not accumulated, and stable dust discharge operation can be performed.

[0043]

As described above, according to the filter-type dust collector of the present invention, the body of the dust-collector is of a cylindrical type, and the inlet of the adsorbent such as powdered activated carbon is provided in the body of the filter-type dust collector. Exhaust gas
By installing at least one above the inlet , the sprayed adsorbent can be efficiently collected on the filter cloth, so organic halogen compounds such as dioxins in exhaust gas can be efficiently adsorbed and removed by the adsorbent. Has the effect that can.

Furthermore, according to the present invention, by setting the adsorbent to be blown out in the tangential direction of the inner peripheral surface from the adsorbent inlet, a swirl flow is generated in the dust collecting chamber, and the adsorbent is filled more uniformly. There is an advantage that the above-mentioned effects are more remarkably obtained because the adsorbent is evenly dispersed in the filter cloth and the adsorbent is uniformly attached to the filter cloth.

Further, according to the present invention, there is provided a simple filter-type dust collector which does not require a new apparatus for removing an organic halogen compound such as a dioxin oxidation catalyst tower, and has a high level of organic halogen compounds such as dioxins. It is possible to provide an excellent filter-type dust collecting apparatus that has a high removal ability and that is capable of performing stable continuous rotation without dust being unduly accumulated in the dust collecting chamber.

[Brief description of drawings]

FIG. 1A is a perspective view showing an embodiment of a filtration type dust collecting apparatus of the present invention, and FIG. 1B is a cross-sectional view of a main part thereof.

FIG. 2 (a) is a cross-sectional view of essential parts showing another embodiment of the filtration dust collector of the present invention, and FIG. 2 (b) is a side view.

FIG. 3 is a perspective view showing an example of a conventional filtration dust collector.

FIG. 4 is a diagram showing an example of a conventional exhaust gas treatment flow.

FIG. 5 is a diagram showing another example of a conventional exhaust gas treatment flow.

FIG. 6 is a diagram further illustrating FIG. 5;

[Explanation of symbols]

1 Filter type dust collector 2 filter cloth 3 Dust discharge hopper 4 Exhaust gas introduction duct 5 Exhaust gas inlet 6 Adsorbent blowing duct 7 Adsorbent blowing 8 Exhaust gas exhaust duct 9 Dust discharging device

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor ▲ Ayu ▼ Masaru Kawai 1-2-1, Marunouchi, Chiyoda-ku, Tokyo Nihonkokankan Co., Ltd. (56) Reference JP-A-4-45827 (JP, A) Kaihei 9-225236 (JP, A) Actual Kaihei 7-25917 (JP, U) JP 54-35713 (JP, B1) JP 47-24340 (JP, Y1) (58) Fields investigated (58) Int.Cl. ⁷ , DB name) B01D 53/34-53/83 B01D 46 / 02,53 / 10

Claims (5)

(57) [Claims] 1. A filter-type dust collector for spraying a powder adsorbent onto exhaust gas discharged along with combustion or heating to remove organic halogen compounds in the exhaust gas, wherein the filter-type dust collector body is a collector. The dust chamber has a cylindrical shape, an exhaust gas introduction port is provided in the lower part of the filtration type dust collector main body, and the dust chamber is provided in the upper part.
A clean exhaust gas duct is installed, and an adsorbent injection port for injecting an adsorbent into the dust collection chamber is provided with the filter-type dust collector.
It said than the exhaust gas inlet of the body above the clean exhaust Gasudaku
A filtration dust collector that is installed at a position lower than the 2. The filtration type dust collecting apparatus according to claim 1, wherein a plurality of the adsorbent blowing ports are provided. 3. The filtration according to claim 1 or 2, wherein the blowing direction of the powder adsorbent blown from the adsorbent blowing port is substantially parallel to the tangential direction of the inner wall circumference of the dust collecting chamber. Type dust collector. 4. The amount of carrier air for blowing the powder adsorbent into the dust collection chamber is 1/100 to 1 of the total exhaust gas treatment amount.
5. The filtration type dust collecting apparatus according to claim 1, wherein the blowing and discharging speed is 10 to 30 m / s. 5. The powder adsorbent has a specific surface area of 100 m.
The filtration dust collector according to claim 1, 2, 3, or 4, wherein a carbon-based porous powder having a weight of ² / g or more is used.