JP2021084086A - Bag filter, method for regenerating impregnated active carbon fiber unit and exhaust gas treatment system - Google Patents

Abstract

To provide a bag filter which can reliably adsorb and remove mercury contained in an incineration furnace waste gas without securing additional power and installation space, and further, does not carry out mercury to a final disposal site, a method for regenerating the bag filter and an exhaust gas treatment system.SOLUTION: This bag filter 4 has an introduction port 4a and an exhaust port 4b for exhaust gas discharged from a refuse incinerator 1, and a casing 43. The bag filter 4 comprises: a filter cloth 41 which captures ash dusts and harmful components which are contained in exhaust gas introduced from the introduction port 4a; and impregnated active carbon fibers 42 which are provided on a downstream side of the filter cloth 41 in an exhaust gas flow direction in the casing 43, and carries an impregnated matter having mercury adsorption ability.SELECTED DRAWING: Figure 2

Description

The present invention relates to a bug filter, a method for regenerating a bug filter, and an exhaust gas treatment system, and more particularly to a technique for reliably adsorbing and removing mercury contained in exhaust gas generated when waste is incinerated.

Conventionally, when treating exhaust gas discharged from a waste incinerator, the temperature is first lowered to 200 ° C. or lower, and then acidic components such as soot, hydrogen chloride and sulfur oxides contained in the exhaust gas, and dioxins. And after removing harmful substances such as mercury, it is released into the atmosphere from the chimney.

As a technique for removing mercury contained in exhaust gas, a technique for adding activated carbon functioning as a mercury adsorbent into exhaust gas containing mercury as shown in Patent Document 1 is known (Patent Document 1). 1). In addition, purification is performed using a technique for removing mercury using a normal activated carbon layer without deposits and an adsorption tower with a built-in bonded activated carbon layer (Patent Document 2), and a filter in which both sides of activated carbon fibers are sandwiched between organic fibers. (Patent Document 3) has been proposed.

Japanese Unexamined Patent Publication No. 2014-213308 Japanese Unexamined Patent Publication No. 2016-185510 JP-A-2002-102652

According to the technique disclosed in Patent Document 1, activated carbon that functions as an adsorbent is put into exhaust gas containing mercury, and the activated carbon that has adsorbed mercury is collected by a filtration type dust collector such as a bag filter. Mercury contained in the exhaust gas can be removed. At this time, the amount of activated carbon consumed can be reduced by providing a mercury concentration detector on the downstream side of the filtration type dust collector and adding activated carbon into the exhaust gas only when the mercury concentration exceeds a predetermined value. it can. However, since the mercury concentration is detected on the downstream side of the filtration type dust collector and the activated carbon is charged on the upstream side of the filtration type dust collector based on the detection result, the concentration is detected and the activated carbon is charged. There was a problem that a time delay occurred during the period and it was not possible to cope with the sudden rise in mercury concentration. In addition, even if the mercury concentration temporarily rises, activated carbon is supplied, which causes wasteful introduction of activated carbon. Further, since the activated carbon adsorbing mercury is discharged as dust collecting ash, there is a problem that the activated carbon containing mercury is carried out to the final disposal site.

On the other hand, according to the technique disclosed in Patent Document 2, since the gas is passed through the packed layer of activated carbon, it is not necessary to control the amount of activated carbon, and the impregnated activated carbon fiber capable of adsorbing mercury and the exhaust gas are sufficiently contacted. Therefore, mercury can be reliably removed. However, since the pressure loss when the exhaust gas passes through the packed layer of activated carbon is large, a large amount of power is required to attract the exhaust gas. Further, the technique disclosed in Patent Document 2 is a technique relating to an adsorption tower for adsorbing mercury and the like, and it is necessary to install an adsorption tower filled with activated carbon in addition to ordinary equipment, and the installation space is secured. I needed it. In addition, there is a risk that activated carbon finely pulverized during handling or deterioration may be scattered in the exhaust gas and discharged from the chimney.

Further, according to the technique disclosed in Patent Document 3, by passing the exhaust gas through the activated carbon fibers sandwiched between the organic fibers, it is possible to adsorb and remove gaseous harmful substances such as dioxin, but the ability to adsorb mercury. Was low, and it was difficult to reliably remove mercury.

The present invention has been made in view of such a problem, and mercury contained in incinerator exhaust gas can be reliably adsorbed and removed without securing additional power or installation space, and mercury can be removed. It is an object of the present invention to provide a bug filter, a method for regenerating the bug filter, and an exhaust gas treatment system that do not carry out the waste to the final disposal site.

The present invention provides the following solutions.

The invention according to the first feature is a bag filter having an intake port, an exhaust port, and a casing for exhaust gas discharged from a waste incinerator, and removes soot and harmful components contained in the exhaust gas introduced from the introduction port. It includes a filter cloth to be captured and an adsorbed activated carbon fiber disposed on the downstream side of the filter cloth in the direction of exhaust gas flow in the casing and carrying an adsorbent having a mercury adsorbing ability.

According to the invention according to the first feature, in addition to being able to capture soot and harmful components by the filter cloth, a new installation space is provided by providing the adhering activated carbon fiber on the downstream side of the filter cloth in the casing. Activated carbon fibers capable of adsorbing mercury can be arranged without preparation. Moreover, by supporting an adsorbent having a mercury adsorbing ability on the activated carbon fiber, the ability to adsorb mercury can be enhanced, and it is possible to reliably remove mercury in a small installation space, which is a contradictory effect. Can be obtained.

The invention according to the second feature is an invention according to the first feature, and uses a compound of iodine or sulfur as an adjunct.

According to the invention according to the second feature, the effect of selectively adsorbing mercury can be enhanced by using a compound of iodine or sulfur as an adsorbent.

The invention according to the third feature is the invention according to the first or second feature, which is an activated carbon blowing means for blowing activated carbon into the exhaust gas on the upstream side of the bag filter, or an activated carbon for adhering activated carbon to a filter cloth. Provided with an attachment means.

According to the invention according to the third feature, mercury can be primarily removed in the preceding stage of the impregnated activated carbon fiber by blowing activated carbon into the exhaust gas or adhering the activated carbon to the filter cloth. Therefore, even if the amount of mercury contained in the exhaust gas is large, mercury can be reliably adsorbed and removed by using the activated carbon in the exhaust gas or the activated carbon adhering to the filter cloth and the impregnated activated carbon fiber.

The invention according to the fourth feature is an invention according to any one of the first to third features, which comprises a substantially the same shape of the impregnated activated carbon fiber unit in which the impregnated activated carbon fiber is unitized, and exhaust gas flow. A plurality of attached activated carbon fiber units were detachably arranged substantially perpendicular to the direction.

According to the invention according to the fourth feature, by unitizing the attached activated carbon fibers, it becomes easy to install the attached activated carbon fibers according to the size of the casing, and it corresponds to a bug filter of various sizes. Can be done. In addition, compatibility between the attached activated carbon units is ensured, costs can be reduced, and delivery time can be shortened by inventory management.

Further, since the attached activated carbon fiber unit can be attached and detached, it can be easily replaced when the adsorptive capacity deteriorates due to long-term use.

The invention according to the fifth feature is the invention according to the fourth feature, in which the impregnated activated carbon fiber units are arranged in a plurality of stages in the exhaust gas flow direction.

According to the invention according to the fifth feature, the mercury adsorption ability can be enhanced by arranging a plurality of stages of impregnated activated carbon fiber units in the exhaust gas flow direction. That is, even if the amount of mercury that cannot be treated by the single stage is contained, it can be reliably adsorbed and removed by using the multi-stage impregnated activated carbon fiber unit.

The invention according to the sixth feature is the invention according to the fifth feature, in which the number of stages to be arranged is increased or decreased according to the amount of mercury contained in the exhaust gas.

According to the invention according to the sixth feature, the adsorptive capacity can be flexibly increased or decreased according to the mercury content, and the minimum necessary amount of the impregnated activated carbon fiber can be used, so that the mercury adsorptive capacity is deteriorated. It is possible to provide a bug filter capable of reliably adsorbing and removing while suppressing.

The invention according to the seventh feature is the invention according to the fifth or sixth feature, in which a carbon fiber unit that selectively adsorbs a harmful substance different from mercury is arranged separately from the impregnated activated carbon fiber unit. did.

According to the invention according to the seventh feature, by disposing a carbon fiber unit that selectively adsorbs harmful substances different from mercury, the adsorption ability of not only mercury but also other harmful substances is enhanced, and various kinds of harmful substances are adsorbed. It is possible to construct an advanced exhaust gas treatment system capable of adsorbing and removing harmful substances.

The invention according to the eighth feature is a method for regenerating the bag filter of the invention according to any one of the fourth to seventh features, in which the removed impregnated activated carbon fiber unit is brought to 600 to 800 ° C. in a reducing atmosphere. It has a step of heating and a step of supporting the attached material on the heated attached activated carbon fiber unit.

According to the invention according to the eighth feature, by heating the activated carbon fiber unit in a reducing atmosphere, only the adhering material and mercury can be desorbed without burning the activated carbon fibers.

Further, after desorbing the adhering material and mercury, the mercury adsorbing ability can be regenerated by supporting the adhering material. Since the mercury adsorbing ability can be regenerated in this way, mercury is not carried out to the final disposal site. In addition, since it is possible to regenerate the mercury adsorption capacity by attaching and detaching each of the attached activated carbon fiber units, if the flow of exhaust gas is biased, only the unit whose adsorption capacity declines significantly should be removed and regenerated. This makes it possible to suppress the occurrence of unnecessary work and enable efficient operation.

The invention according to the ninth feature is the bag filter of the invention according to any one of the first to seventh features, and is arranged on the upstream side of the bug filter to neutralize the acidic component contained in the exhaust gas. It is an exhaust gas treatment system including a chemical supply device for supplying chemicals and mercury adsorbents in exhaust gas and to a bug filter.

According to the invention according to the ninth feature, since the chemical supply device is provided on the upstream side of the bug filter, it is possible to perform advanced exhaust gas treatment capable of removing soot and neutralizing acidic components and adsorbing mercury with one bug filter. It is possible to construct an exhaust gas treatment system.

According to the present invention, mercury contained in incinerator exhaust gas can be reliably adsorbed and removed without securing additional power or installation space, and mercury is not carried out to the final disposal site. A filter, a method for regenerating a bug filter, and an exhaust gas treatment device can be provided.

FIG. 1 is a schematic view showing an exhaust gas treatment system according to the present embodiment. FIG. 2 is a diagram showing an internal configuration of the bug filter according to the present embodiment, showing a state in which the flow path switching valve is open. FIG. 3 is a diagram showing an internal configuration of the bug filter according to the present embodiment, and shows a state in which the flow path switching valve is closed. FIG. 4 is a diagram showing a flowchart for explaining a method of reproducing the bug filter according to the present embodiment. FIG. 5 is a diagram showing an internal configuration of a bug filter according to a modified example. FIG. 6 is a diagram showing an internal configuration of a bug filter according to a modified example, and shows a state in which one of a plurality of flow path switching valves is open.

Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. It should be noted that this is only an example, and the technical scope of the present invention is not limited to this.

[Structure of exhaust gas treatment system]
The configuration of the exhaust gas treatment system according to the present embodiment will be described with reference to FIG.

As shown in FIG. 1, the exhaust gas treatment system of the present embodiment includes a waste incinerator 1, a heat recovery device 2 composed of an exhaust heat recovery boiler and an economizer, a gas cooling device 3, a bag filter 4, and an induction ventilator. It is composed of 5, a chimney 6, a drug supply device 7, a mercury concentration detection device 8 provided on the downstream side of the bag filter 4, and a control device 9.

The waste incinerator 1 incinerates irregularly shaped general waste, industrial waste, infectious medical waste in a package having a predetermined shape, and the like, and is a stoker type and fluidized type. Any type of incinerator, such as layered or vertical, is used.

The heat recovery device 2 recovers heat from the high-temperature exhaust gas generated when waste is incinerated in the waste incinerator 1, and is, for example, an exhaust heat recovery boiler equipped with an evaporator or an exhaust heat recovery boiler. It is composed of an economizer that heats the boiler water supply upstream.

The gas cooling device 3 is capable of supplying the temperature of the exhaust gas discharged from the waste incinerator 1 and the heat recovery device 2 to the bag filter 4, and is described in the "Guidelines for Prevention of Dioxins Generation Related to Waste Disposal". The temperature is reduced to about 200 ° C or less, and the type does not matter.

The bag filter 4 removes soot and harmful components contained in the exhaust gas by filtering the exhaust gas whose temperature has been reduced by the gas cooling device 3, and as shown in FIGS. 2 and 3, the soot and dust and the like are removed. The filter cloth 41 for filtering harmful components, the adsorbed activated carbon fiber 42 in which an adsorbent having a function of adsorbing mercury is supported on the activated carbon fiber, the filter cloth 41 and the casing 43 containing the adhering activated carbon fiber 42 are included. The details of the bug filter 4 will be described later.

The attractive ventilator 5 is a ventilator arranged downstream of the bug filter 4 and is for sucking the exhaust gas purified by the bug filter 4 and releasing the exhaust gas from the chimney 6 to the atmosphere.

The chemical supply device 7 provides an alkaline chemical for neutralizing acidic components such as hydrogen chloride and sulfur oxides contained in the exhaust gas, and an adsorbent for adsorbing harmful substances such as mercury contained in the exhaust gas. It is supplied in the exhaust gas and to the bag filter 4, and is arranged on the upstream side of the bag filter 4, preferably in the flue between the gas cooling device 3 and the bag filter 4.

In this embodiment, slaked lime is used as the alkaline agent and activated carbon is used as the adsorbent. In particular, by using activated carbon as the mercury adsorbent, it becomes possible to effectively treat mercury using a relatively easily available adsorbent. The types of chemicals and mercury adsorbents used are not limited to this.

Then, in the present embodiment, the alkaline drug and the adsorbent are supplied from the drug supply device 7 into the bag filter 4 via the flue gas stack for a predetermined time, so that the surface of the filter cloth 41 of the bag filter 4 has a predetermined thickness. A precoat treatment is performed to form a precoat layer of the chemical and the adsorbent.

In this way, the drug supply device 7 functions as the activated carbon blowing means and the activated carbon adhering means in the present invention.

The mercury concentration detecting device 8 is installed on the downstream side of the bag filter 4 and is configured to continuously detect the mercury concentration after being adsorbed by the adsorbent and the adsorbed activated carbon fiber 42.

The control device 9 controls the switching of the flow path switching means 45, which will be described later, and the supply of the alkaline drug and the adsorbent from the drug supply device 7 based on the mercury concentration detected by the mercury concentration detection device 8.

In the present embodiment, the mercury concentration detecting device 8 is installed on the downstream side of the bug filter 4, but the mercury concentration detecting device 8 may be installed on the upstream side of the bug filter 4.

[Bug filter 4]
Next, the bug filter 4 in the present embodiment will be described with reference to FIGS. 2 and 3. FIG. 2 is a diagram showing the internal configuration of the bug filter 4 according to the present embodiment, showing a state in which the flow path switching means 45 described later is open, and FIG. 3 shows the flow path switching means 45 closed. It shows the state of the bug.

The bag filter 4 purifies the exhaust gas cooled by the cooling device 3, and includes an exhaust gas introduction port 4a provided below, a filter cloth 41 for filtering soot and harmful components contained in the exhaust gas, and the like. It is composed of an attached activated carbon fiber 42 that further adsorbs harmful components from the exhaust gas after flowing through the filter cloth 41, a casing 43 that houses the filter cloth 41 and the attached activated carbon fiber 42, and an exhaust gas discharge port 4b provided above. ..

In the casing 43, a partition wall 43c is installed that partitions the internal space of the casing 43 into an upper space 43a in which the adhering activated carbon fibers 42 are arranged and a lower space 43b in which the filter cloth 41 is arranged. ..

The filter cloth 41 captures soot and harmful components contained in the exhaust gas introduced into the lower space 43b of the casing 43, and is made of woven cloth or non-woven fabric and has one end opened and the other end closed. Is formed as an aggregate of. Each tubular body is arranged so that an end portion having an opening penetrates a plurality of openings formed in the partition wall 43c.

In the present embodiment, the tubular body having the lower end closed and the upper end opened is arranged in a plurality of openings provided in the width direction and the depth direction of the partition wall 43c, so that the exhaust gas flowing in from below It forms a filter cloth 41 capable of catching soot and dust.

That is, the exhaust gas introduced into the lower space 43b of the casing 43 and flowing from the lower side to the upper side passes through the filter cloth 41 whose lower end is closed and flows into the upper space 43a through the opening at the upper end. Then, when passing through the filter cloth 41, soot and dust contained in the exhaust gas are removed, and the exhaust gas becomes purified and flows into the upper space 43a.

As described above, the surface of the filter cloth 41 of the bag filter 4 according to the present embodiment is precoated with an alkaline agent and an adsorbent, so that in addition to the filtering effect of soot and dust, hydrogen chloride, sulfur oxides, etc. And harmful components such as mercury can be effectively purified and adsorbed.

In the upper space 43a, a pulse jet pipe (not shown) is arranged at a position facing the plurality of openings formed in the partition wall 43c, and the pulse jet pipe is directed toward the opening of the partition wall 43c. By periodically ejecting compressed air or the like, soot and dust adhering to the filter cloth 41 are periodically blown off.

As the adsorbed activated carbon fiber 42 that adsorbs mercury, activated carbon fiber or activated carbon fiber in which an adsorbent that adsorbs harmful components is carried on the surface of activated carbon fiber (ACF) is used. ACF has an excellent function of adsorbing and removing harmful components such as nitrogen oxides, dioxins, polychlorinated biphenyls (PCBs), mercury and odors contained in exhaust gas.

In the present embodiment, an adsorbent effective for mercury adsorption, particularly a compound of iodine or sulfur, is adsorbed on the surface of the adsorbed activated carbon fiber 42 in order to enhance the ability to adsorb mercury, and the contact area is small. Even if it exists, it can effectively adsorb harmful substances such as mercury.

The impregnated activated carbon fiber 42 is installed in the upper space 43a of the casing 43 so as to partition the upper space 43a from the upstream side and the downstream side in the exhaust gas distribution direction.

That is, in the attached activated carbon fibers 42 of the bag filter 4 according to the present embodiment, a plurality of the attached activated carbon fiber units having substantially the same shape are placed substantially perpendicular to the exhaust gas flow direction, that is, substantially on the same plane. It is configured to be detachably arranged side by side, and the upper space 43a is divided into a portion located above and a portion located below by the attached activated carbon fiber 42. At that time, each of the attached activated carbon fiber units constituting the attached activated carbon fiber 42 is arranged side by side in the width direction and the depth direction on the support frame 42s arranged at a predetermined height.

The exhaust gas discharge flow path 44 is connected to the upper space 43a of the casing, and the discharge flow path 44 is located above by the partition plate 44c arranged at a predetermined height, and the impregnated activated carbon fiber 42 is attached. It is divided into a short-circuit flow path 44a through which the exhaust gas after flowing through flows, and a bypass flow path 44b located below and discharging the exhaust gas without passing through the impregnated activated carbon fiber 42.

That is, as described above, the upper space 43a of the casing is divided into the upstream side and the downstream side in the exhaust gas flow direction by the cohesive activated carbon fiber 42, but the short-circuit flow path 44a communicates with the space on the downstream side of the cohesive activated carbon fiber 42. The detour flow path 44b communicates with the space on the upstream side of the impregnated activated carbon fiber 42.

In the discharge flow path 44, a short-circuit flow path 44a through which the exhaust gas after passing through the cohesive activated carbon fiber 42 flows and a detour flow path 44b through which the exhaust gas that does not pass through the cohesive activated carbon fiber 42 flows are selectively distributed. The flow path switching means 45 is provided.

In the present embodiment, the flow path switching means 45 is composed of a flow path on-off valve installed in the bypass flow path 44b, and the bypass flow path 44b is powered by a motor (not shown) in accordance with a command from the control device 9. It is configured so that it can be switched between open and closed.

That is, as shown in FIG. 3, when the bypass flow path 44b is closed by operating the flow path switching means 45, the exhaust gas flowing into the upper space 43a is purified by flowing through the impregnated activated carbon fiber 42. , Is discharged from the exhaust gas discharge port 4b via the short-circuit flow path 44a.

On the other hand, as shown in FIG. 2, when the bypass flow path 44b is opened by operating the flow path switching means 45, the ventilation resistance of the attached activated carbon fiber 42 causes the flow path switching means 45 and the bypass flow path 44b to be ventilated. Since it is larger than the resistance, the exhaust gas flowing into the upper space 43a bypasses the impregnated activated carbon fiber 42, passes through the flow path switching means 45 and the bypass flow path 44b, and is discharged from the exhaust gas discharge port 4b.

In the present embodiment, the support frame 42s on which the impregnated activated carbon fiber 42 is installed and the partition plate 44c are arranged on substantially the same plane as separate members, but the support frame 42s and the partition plate 44c are the same. It may be configured as a member.

The bag filter 4 according to the present embodiment configured as described above can capture soot and harmful components by the filter cloth 41, and in addition, the activated carbon fibers 42 adsorbed on the downstream side of the filter cloth 41 in the casing 43. By providing the above, it is possible to dispose of activated carbon fibers capable of adsorbing mercury without preparing a new installation space. Moreover, by supporting an adsorbent having a mercury adsorbing ability on the activated carbon fiber, the ability to adsorb mercury can be enhanced, and it is possible to reliably remove mercury in a small installation space, which is a contradictory effect. Can be obtained. Further, even if an adhering material is impregnated on the activated carbon fiber, the pressure loss is small, so that the operation can be performed without adding power consumption.

Further, by using a compound of iodine or sulfur as an adsorbent, the effect of selectively adsorbing mercury can be enhanced.

Further, by blowing activated carbon into the exhaust gas or adhering activated carbon to the filter cloth 41, mercury can be primarily removed in the preceding stage of the impregnated activated carbon fiber 42. Therefore, even if the amount of mercury contained in the exhaust gas is large, mercury can be reliably adsorbed and removed by using the activated carbon in the exhaust gas or the activated carbon adhering to the filter cloth 41 and the impregnated activated carbon fiber 42. Further, since the load on the attached activated carbon fiber 42 is reduced by first removing mercury in the preceding stage of the attached activated carbon fiber 42, the life of the attached activated carbon fiber 42 can be extended.

Further, by configuring the attached activated carbon fibers 42 by using the attached activated carbon fiber units having substantially the same shape, it becomes easy to install the attached activated carbon fibers 42 according to the size of the casing 43, and bugs of various sizes can be easily installed. It can correspond to the filter 4.

Further, since the attached activated carbon fiber unit having substantially the same shape can be attached and detached, it becomes easy to replace the attached activated carbon fiber 42 when the adsorption ability of the attached activated carbon fiber 42 deteriorates due to long-term use.

Further, not only mercury but also dioxins can be adsorbed, and since it is fibrous, it has a soundproofing effect that it can absorb the pulse sound when the filter cloth 41 is wiped off.

[Regeneration of Adhered Activated Carbon Fiber 42]
Next, the regeneration of the impregnated activated carbon fiber 42 will be described with reference to FIG.

With the long-term use of the impregnated activated carbon fiber 42, mercury adsorbed from the exhaust gas accumulates on the surface, so that the function of the adsorbed material deteriorates. If this state is left unattended, mercury cannot be completely adsorbed by the bug filter 4 and is taken out downstream, which is not preferable. Therefore, the function is restored by replacing the impregnated activated carbon fiber unit whose function has deteriorated. The procedure for functional recovery will be described below.

[Step S100: Removal of unit]
First, when the mercury concentration detection device 8 detects a decrease in the mercury adsorption capacity, that is, when an increase in the detection value in the mercury concentration detection device 8 provided downstream of the bag filter 4 is detected, the operation of the waste incinerator 1 is stopped. Then, the operation of removing the impregnated activated carbon fiber unit having a reduced function from the adsorbed activated carbon fibers 42 is performed (step S100).

When removing the attached activated carbon fiber unit, since each attached activated carbon fiber unit is individually and detachably installed, only the impregnated activated carbon fiber unit with reduced function can be removed.

When removing the impregnated activated carbon fiber unit, it is not always necessary to perform it while the operation of the waste incinerator 1 is stopped. The activated carbon fiber unit may be replaced.

Alternatively, during periodic inspections and the like, it may be possible to visually confirm the functional deterioration of the individual impregnated activated carbon fiber units and remove only the impregnated activated carbon fiber units having the deteriorated functions.

[Step S110: Heating in a reducing atmosphere]
Next, the activated carbon fiber unit removed in step S100 is heated to 600 to 800 ° C. in a reducing atmosphere to desorb mercury (step S110).

The activated carbon fibers are burnt by simply heating to a high temperature, but in the present embodiment, since the heating is performed in a reducing atmosphere, only the adhering material and mercury are removed without burning the activated carbon fibers. Can be separated.

[Step S120: Reattachment of attachment]
In step S110, the adhering material is re-adhered to the adhering activated carbon fiber unit heated in the reducing atmosphere (step S120).

In step S110, heating is performed in a reducing atmosphere, and the adsorbent is attached to the activated carbon fiber in a state where the adsorbent and mercury are desorbed. Therefore, the ability to adsorb mercury is regenerated without leaving impurities. Can be done.

As described above, according to the method for regenerating the adhering activated carbon fibers according to the present embodiment, by heating the removed impregnated activated carbon fibers in a reducing atmosphere, only the adhering material and mercury are used without burning the activated carbon fibers. Can be attached and detached.

Then, after desorbing the adhering material and mercury, the mercury adsorbing ability can be regenerated by supporting the adhering material again. Since the mercury adsorbing ability can be regenerated in this way, mercury is not carried out to the final disposal site. In addition, since it is possible to regenerate the mercury adsorption capacity by attaching and detaching each of the attached activated carbon fiber units, if the flow of exhaust gas is biased, only the unit whose adsorption capacity declines significantly should be removed and regenerated. This makes it possible to suppress the occurrence of unnecessary work and enable efficient operation.

In addition, by mounting the adsorbed activated carbon fiber unit having the ability to adsorb mercury by supporting the adhering material at the place where the adsorbed activated carbon fiber unit was removed in step S100, there is no gap and sufficient mercury adsorbing ability is obtained. The adsorbed activated carbon fiber 42 can be regenerated in the bag filter 4.

[Modification example]
As shown in FIG. 5, the impregnated activated carbon fibers 42 can be arranged in a plurality of stages.

That is, the length of the impregnated activated carbon fiber unit in the exhaust gas flow direction in the present invention is about 100 mm, and mercury in the exhaust gas is adsorbed when the exhaust gas flows through the impregnated activated carbon fiber unit. If the amount of mercury is excessive, it may not be completely adsorbed.

Therefore, when the amount of mercury in the waste is larger than usual, the mercury adsorbing ability can be enhanced and mercury can be reliably adsorbed by using a plurality of layers of the impregnated activated carbon fibers 42. ..

Further, the number of stages can be increased or decreased according to the amount of mercury contained in the exhaust gas. By doing so, it is possible to construct a system that can flexibly respond by increasing or decreasing the adsorption capacity according to the mercury content.

Specifically, as shown in FIG. 6, a plurality of stages of adhered activated carbon fibers 42a, 42b, 42c, ... Are arranged in the upper space 43a of the bag filter 4 at intervals in the vertical direction, respectively. On-off valves 45a, 45b, 45c, 45d, ... Are arranged in the flow path formed between the attached activated carbon fibers 42a, 42b, 42c, .... Note that FIG. 6 describes the case where the three-stage bonded activated carbon fibers 42a, 42b, and 42c are used, but this is just an example, and the number of stages of the bonded activated carbon fibers 42 used is limited to this. is not it.

The control device 9 controls the plurality of on-off valves 45a, 45b, 45c, 45d, ... Arranged in this manner based on the mercury concentration detected by the mercury concentration detecting means 8. The flow path is selectively opened and closed to determine the number of stages of the impregnated activated carbon fiber 42 to be used. In the example shown in FIG. 6, only one of the plurality of flow path switching valves 45a, 45b, 45c, 45d is opened, and the other flow path switching valves 45a, 45b, 45d are closed. The state in which the exhaust gas is circulated through the two-stage impregnated activated carbon fibers 42a and 42b is shown.

By doing so, the adsorption capacity can be flexibly increased or decreased according to the mercury content, and the minimum necessary amount of the impregnated activated carbon fiber can be used, so that the deterioration of the mercury adsorption capacity can be suppressed. However, it is possible to provide a bug filter capable of reliable adsorption removal.

Further, when arranging the multi-stage filter including the impregnated activated carbon fiber 42, the carbon fiber unit that selectively adsorbs a harmful substance different from mercury can be arranged.

By doing so, we provide a bug filter that enhances the adsorption capacity of not only mercury but also other harmful substances and makes it possible to construct an advanced exhaust gas treatment system capable of adsorbing and removing various harmful substances. it can.

Although the embodiments of the present invention have been described above, the present invention is not limited to these embodiments described above. In addition, the effects described in the embodiments of the present invention merely list the most preferable effects arising from the present invention, and the effects according to the present invention are limited to those described in the embodiments of the present invention. is not it.

Further, the above-described embodiment has been described in detail in order to explain the present invention in an easy-to-understand manner, and is not necessarily limited to the one including all the described configurations. Further, it is possible to replace a part of the configuration of one embodiment with the configuration of another embodiment, and it is also possible to add the configuration of another embodiment to the configuration of one embodiment. .. In addition, other configurations may be added, deleted, or replaced with respect to a part of the configurations of each embodiment.

The bag filter, the method for regenerating the bag filter, and the exhaust gas treatment system of the present invention can be applied to all mercury-containing exhaust gas, including industrial waste incineration equipment that may treat mercury-containing waste. it can.

1 Garbage incinerator 2 Heat recovery device 3 Gas cooling device 4 Bug filter 4a Exhaust gas introduction port 4b Exhaust gas discharge port 41 Filter cloth 42 Adhered activated carbon fiber 43 Casing 43a Upper space 43b Lower space 43c Partition wall 44 Discharge flow path 44a Short circuit flow path 44b Bypass flow path 44c Partition plate 45 Flow path switching means 5 Induction blower 6 Chimney 7 Chemical supply device 8 Mercury concentration detection device 9 Control device

The present invention has been made in view of such a problem, and mercury contained in the incinerator exhaust gas can be reliably adsorbed and removed without securing additional power or installation space, and moreover, it is adsorbed. It is an object of the present invention to provide a bag filter, a method for regenerating the bag filter, and an exhaust gas treatment system capable of reducing the amount of mercury carried out to the final disposal site by recycling the produced mercury.

According to the invention according to the third feature, mercury can be primarily removed in the preceding stage of the impregnated activated carbon fiber by blowing activated carbon into the exhaust gas or adhering the activated carbon to the filter cloth. Therefore, even if the amount of mercury contained in the exhaust gas is large , mercury can be reliably adsorbed and removed by using the activated carbon blown into the exhaust gas or the activated carbon attached to the filter cloth and the impregnated activated carbon fibers.

According to the invention according to the fourth feature, by unitizing the attached activated carbon fibers, it becomes easy to install the attached activated carbon fibers according to the size of the casing, and it corresponds to a bug filter of various sizes. Can be done. In addition, compatibility between the attached activated carbon fiber units is ensured, costs can be reduced, and delivery time can be shortened by inventory management.

Further, after desorbing the adhering material and mercury, the mercury adsorbing ability can be regenerated by supporting the adhering material. Since the mercury adsorbing ability can be regenerated in this way, it is possible to reduce the amount of mercury carried out to the final disposal site by desorbing and recycling the adsorbed mercury. In addition, since it is possible to regenerate the mercury adsorption capacity by attaching and detaching each of the attached activated carbon fiber units, if the flow of exhaust gas is biased, only the unit whose adsorption capacity declines significantly should be removed and regenerated. This makes it possible to suppress the occurrence of unnecessary work and enable efficient operation.

As the adsorbed activated carbon fiber 42 that adsorbs mercury, activated carbon fiber or activated carbon fiber in which an adsorbent that adsorbs harmful components is carried on the surface of activated carbon fiber (ACF) is used. ACF is nitrogen oxides contained in the exhaust gas, dioxin, polychlorinated biphenyl (PCB), and has excellent ability to remove adsorbed harmful components such as odor.

Then, after desorbing the adhering material and mercury, the mercury adsorbing ability can be regenerated by supporting the adhering material again. Since the mercury adsorbing ability can be regenerated in this way, it is possible to reduce the amount of mercury carried out to the final disposal site by desorbing and recycling the adsorbed mercury. In addition, since it is possible to regenerate the mercury adsorption capacity by attaching and detaching each of the attached activated carbon fiber units, if the flow of exhaust gas is biased, only the unit whose adsorption capacity declines significantly should be removed and regenerated. This makes it possible to suppress the occurrence of unnecessary work and enable efficient operation.

The present invention relates to a bag filter, a method for regenerating an impregnated activated carbon fiber unit , and an exhaust gas treatment system, and more particularly to a technique for reliably adsorbing and removing mercury contained in exhaust gas generated when waste is incinerated.

The present invention has been made in view of such a problem, and mercury contained in the incinerator exhaust gas can be reliably adsorbed and removed without securing additional power or installation space, and mercury can be removed. It is an object of the present invention to provide a bag filter, a method for regenerating an impregnated activated carbon fiber unit , and an exhaust gas treatment system that do not carry out the waste to the final disposal site.

The invention according to the first feature is a bag filter having an inlet and an outlet for exhaust gas discharged from a waste incinerator, and captures soot and harmful components contained in the exhaust gas introduced from the inlet. It is provided with a filter cloth and an adhering activated carbon fiber unit arranged on the downstream side of the filter cloth in the exhaust gas flow direction and carrying an adhering material having a mercury adsorbing ability, and a plurality of adhering substantially perpendicular to the exhaust gas flow direction. The activated carbon fiber unit is detachably arranged, and the removed attached activated carbon fiber unit is heated to 600 to 800 ° C. in a reducing atmosphere to desorb mercury and the attached material, and the heated attached activated carbon fiber unit is removed. It has the function of supporting and regenerating the adhering material .

According to the invention according to the first feature, in addition to being able to capture soot and harmful components by the filter cloth, a new installation space is prepared by providing the adsorbed activated carbon fiber on the downstream side of the filter cloth. It is possible to dispose of activated carbon fibers capable of adsorbing mercury. Moreover, by supporting an adsorbent having a mercury adsorbing ability on the activated carbon fiber, the ability to adsorb mercury can be enhanced, and it is possible to reliably remove mercury in a small installation space, which is a contradictory effect. Can be obtained.

Further, by unitizing the attached activated carbon fibers, it becomes easy to install the attached activated carbon fibers according to the size of the casing, and it is possible to correspond to bug filters of various sizes. In addition, compatibility between the attached activated carbon units is ensured, costs can be reduced, and delivery time can be shortened by inventory management. Further, since the attached activated carbon fiber unit can be attached and detached, it can be easily replaced when the adsorptive capacity deteriorates due to long-term use.

Further, by heating the activated carbon fiber unit in a reducing atmosphere, only the adhering material and mercury can be desorbed without burning the activated carbon fibers.

Then, after desorbing the adhering material and mercury, the mercury adsorbing ability can be regenerated by supporting the adhering material. Since the mercury adsorbing ability can be regenerated in this way, mercury is not carried out to the final disposal site. In addition, since it is possible to regenerate the mercury adsorption capacity by attaching and detaching each of the attached activated carbon fiber units, if the flow of exhaust gas is biased, only the unit whose adsorption capacity declines significantly should be removed and regenerated. This makes it possible to suppress the occurrence of unnecessary work and enable efficient operation.

The invention according to the second feature is an invention according to the first feature, and uses a compound of iodine or sulfur as an adjunct.

According to the invention according to the second feature, the effect of selectively adsorbing mercury can be enhanced by using a compound of iodine or sulfur as an adsorbent.

The invention according to the third feature is the invention according to the first or second feature, which is an activated carbon blowing means for blowing activated carbon into the exhaust gas on the upstream side of the bag filter, or an activated carbon for adhering activated carbon to a filter cloth. Provided with an attachment means.

According to the invention according to the third feature, mercury can be primarily removed in the preceding stage of the impregnated activated carbon fiber by blowing activated carbon into the exhaust gas or adhering the activated carbon to the filter cloth. Therefore, even if the amount of mercury contained in the exhaust gas is large, mercury can be reliably adsorbed and removed by using the activated carbon in the exhaust gas or the activated carbon adhering to the filter cloth and the impregnated activated carbon fiber.

The invention according to the fourth feature is the invention according to any one of the first to third features, in which the impregnated activated carbon fiber units are arranged in a plurality of stages in the exhaust gas flow direction.

According to the invention according to the fourth feature, the mercury adsorption ability can be enhanced by arranging a plurality of stages of impregnated activated carbon fiber units in the exhaust gas flow direction. That is, even if the amount of mercury that cannot be treated by the single stage is contained, it can be reliably adsorbed and removed by using the multi-stage impregnated activated carbon fiber unit.

The invention according to the fifth feature is the invention according to the fourth feature, in which the number of stages in which the impregnated activated carbon fiber unit is arranged is increased or decreased according to the amount of mercury contained in the exhaust gas.

According to the invention according to the fifth feature, the adsorptive capacity can be flexibly increased or decreased according to the mercury content, and the minimum necessary amount of the impregnated activated carbon fiber can be used. It is possible to provide a bug filter capable of reliably adsorbing and removing while suppressing.

The invention according to the sixth feature is the invention according to the fourth or fifth feature, in which a carbon fiber unit that selectively adsorbs a harmful substance different from mercury is arranged separately from the impregnated activated carbon fiber unit. did.

According to the invention according to the sixth feature, by disposing a carbon fiber unit that selectively adsorbs harmful substances different from mercury, the adsorption ability of not only mercury but also other harmful substances is enhanced, and various kinds of harmful substances are adsorbed. It is possible to construct an advanced exhaust gas treatment system capable of adsorbing and removing harmful substances.

The invention according to the seventh feature is a method for regenerating the impregnated activated carbon fiber unit of the invention according to any one of the first to sixth features, wherein the removed impregnated activated carbon fiber unit is 600 to 800 in a reducing atmosphere. It has a step of heating to ° C. and a step of supporting the adhering material on the heated adhering activated carbon fiber unit.

According to the invention according to the seventh feature, by heating the activated carbon fiber unit in a reducing atmosphere, only the adhering material and mercury can be desorbed without burning the activated carbon fibers.

The invention according to the eighth feature is the bag filter of the invention according to any one of the first to sixth features, and is arranged on the upstream side of the bug filter to neutralize the acidic component contained in the exhaust gas. It is an exhaust gas treatment system including a chemical supply device for supplying chemicals and mercury adsorbents in exhaust gas and to a bug filter.

According to the invention according to the eighth feature, since the chemical supply device is provided on the upstream side of the bag filter, it is possible to perform advanced exhaust gas treatment capable of removing soot and neutralizing acidic components and adsorbing mercury with one bag filter. It is possible to construct an exhaust gas treatment system.

The bag filter of the present invention, the method for regenerating the impregnated activated carbon fiber unit , and the exhaust gas treatment system are applied to all types of exhaust gas containing mercury, including industrial waste incinerators that may treat mercury-containing waste. can do.

Claims (9)

It is a bug filter that has an intake port and an exhaust port for the exhaust gas discharged from the waste incinerator.
A filter cloth that captures soot and harmful components contained in the exhaust gas introduced from the introduction port, and
An impregnated activated carbon fiber disposed on the downstream side of the filter cloth in the exhaust gas flow direction and carrying an adsorbent having a mercury adsorbing ability.
Bug filter with. The bug filter according to claim 1, wherein a compound of iodine or sulfur is used as the adhering substance. The bug filter according to claim 1 or 2, further comprising an activated carbon blowing means for blowing activated carbon into the exhaust gas on the upstream side of the bag filter, or an activated carbon adhering means for adhering the activated carbon to the filter cloth. The present invention, wherein the attached activated carbon fiber unit having substantially the same shape as a unit of the attached activated carbon fiber is provided, and a plurality of the attached activated carbon fiber units are detachably arranged substantially perpendicular to the exhaust gas flow direction. The bug filter described in any of 1-3. The bug filter according to claim 4, wherein the impregnated activated carbon fiber units are arranged in a plurality of stages in the exhaust gas flow direction. The bug filter according to claim 5, wherein the number of stages to be arranged is increased or decreased according to the amount of mercury contained in the exhaust gas. The bug filter according to claim 5 or 6, wherein a carbon fiber unit that selectively adsorbs a harmful substance different from mercury is arranged separately from the attached activated carbon fiber unit. A step of heating the removed attached activated carbon fiber unit to 600 to 800 ° C. in a reducing atmosphere.
A step of supporting an adhering material on the heated adhering activated carbon fiber unit,
The method for reproducing the bug filter according to any one of claims 4 to 7. The bug filter according to claims 1 to 7 and
A drug supply device disposed on the upstream side of the bag filter and supplying a drug and a mercury adsorbent for neutralizing an acidic component contained in the exhaust gas to the exhaust gas and the bag filter.
Exhaust gas treatment system equipped with.

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