CN113477047B

CN113477047B - Exhaust gas treatment device and incineration equipment

Info

Publication number: CN113477047B
Application number: CN202110805815.7A
Authority: CN
Inventors: 古林通孝; 前田优佑; 加藤睦史
Original assignee: Hitachi Zosen Corp
Current assignee: Hitachi Zosen Corp
Priority date: 2016-12-02
Filing date: 2017-11-14
Publication date: 2023-05-16
Anticipated expiration: 2037-11-14
Also published as: JP2022031277A; CN113477047A; CN110036240A; PH12019501185A1; JPWO2018101029A1; CN110036240B; MY201579A; JP6980693B2; WO2018101029A1; JP7146049B2

Abstract

The invention provides an exhaust gas treatment device and an incineration apparatus. The exhaust gas treatment device (4) comprises: a dust collector (43) provided in a flue (3) through which exhaust gas flows; a chemical supply unit (42) for supplying an exhaust gas treatment chemical to a chemical supply position (P1) between the combustion chamber (2) and the dust collector (43) in the flue (3); a collected dust conveying unit (44) that conveys, by means of a conveyor, collected dust collected by the dust collector (43) along an auxiliary path (441) different from the flue (3) to a collected dust supply position (P2) between the combustion chamber (2) in the flue (3) and the dust collector (43); and a collected ash heating part provided in the auxiliary path (441) for heating the collected ash. Thereby, adhesion of the collected ash in the auxiliary path (441) can be suppressed, the conveyor comprising a housing, the pressure inside the housing being higher than the pressure inside the flue, the exhaust gas being prevented from flowing into the housing.

Description

Exhaust gas treatment device and incineration equipment

The present application is a divisional application of patent application 201780074551.4, which has a filing date of 2017, 11, 14 and is entitled "exhaust gas treatment apparatus and incineration plant".

Technical Field

The present invention relates to an exhaust gas treatment device and an incineration apparatus.

Background

Conventionally, general waste such as municipal waste is incinerated by a waste incineration facility. The exhaust gas generated by the incineration treatment contains harmful substances such as coal dust, hydrogen chloride (HCl), sulfur oxides (SOx), nitrogen oxides (NOx), heavy metals (Pb, hg, etc.). Therefore, the exhaust gas treatment device performs the treatment of removing the above-mentioned harmful substances from the exhaust gas, and discharges the treated exhaust gas to the atmosphere.

For example, japanese patent laid-open publication No. Sho 59-150525 (document 1) discloses the following method: in the step of removing harmful acid gas components such as hydrogen chloride by blowing slaked lime powder into the exhaust gas, a part of the collected ash collected by the dust collector is crushed and sent into the flue by the air blower, whereby a part of the collected ash is reused for acid gas removal. Further, japanese patent laid-open publication No. 2014-24052 (document 2) discloses the following method: and taking part of the treated waste gas as carrier gas, and returning part of the collected dust collected by the dust collector to the flue at the inlet side of the dust collector.

However, in the methods of the

documents

1 and 2, in the pipe for returning the collected ash to the flue, the collected ash is cooled by the carrier gas, and the collected ash (particularly, calcium chloride or the like) absorbs moisture in the carrier gas and becomes liquid (i.e., deliquesces). Thereby, the collected ash adheres to the inner surface of the pipe. In general, the diameter of the piping is not too large, and therefore, adhesion of the collected ash may cause the collected ash to be not properly returned to the flue.

Disclosure of Invention

The invention relates to an exhaust gas treatment device, which aims to inhibit adhesion of collected dust in a path for returning the collected dust to a flue.

The exhaust gas treatment device of the present invention comprises: the dust collector is arranged on the flue for circulating the waste gas; a chemical supply unit configured to supply an exhaust gas treatment chemical to a chemical supply position between the dust collector and the source of exhaust gas generated in the flue; a collected dust conveying unit that conveys collected dust collected by the dust collector to a collected dust supply position between the generation source and the dust collector in the flue along an auxiliary path different from the flue by a conveyor; and a collected dust heating unit provided in the auxiliary path for heating the collected dust, wherein the conveyor includes a housing, the pressure in the housing is higher than the pressure in the flue, the exhaust gas is prevented from flowing into the housing, the conveyor has a plurality of holding units provided along the auxiliary path and holding the collected dust in a block state in the housing, and the conveyor conveys the plurality of holding units along the auxiliary path.

According to the present invention, adhesion of the collected ash in the auxiliary path for returning the collected ash to the flue can be suppressed.

In a preferred embodiment of the present invention, the exhaust gas treatment agent contains a calcium-based agent.

In another preferred aspect of the present invention, the collected ash conveying section includes a conveyor having a plurality of holding sections provided along the auxiliary path, and the conveyor conveys the plurality of holding sections accommodating the collected ash along the auxiliary path.

In this case, the collected ash conveying section preferably further includes a chute section for dropping the collected ash accommodated in each holding section.

Further preferably, the collected ash conveying section further includes a crushing section that crushes the collected ash by colliding with the thrown-in collected ash in the chute section.

In another preferred aspect of the present invention, the collected dust transporting section includes a collected dust storing section provided in the auxiliary path and storing the collected dust, and the collected dust heating section heats the collected dust in the collected dust storing section.

In this case, it is preferable that the exhaust gas treatment device further includes a collected ash vibrating portion that vibrates a vicinity of a portion of the collected ash storage portion heated by the collected ash heating portion.

The invention also relates to an incineration plant. The incineration apparatus of the present invention includes: a combustion chamber for burning waste; a flue that discharges exhaust gas generated in the combustion chamber from the combustion chamber; and the exhaust gas treatment device is arranged on the flue.

The above objects and other objects, features, aspects and advantages of the present invention will become apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings.

Drawings

Fig. 1 is a diagram showing a structure of an incinerator.

Fig. 2 is a diagram showing a structure of the exhaust gas treatment device.

Fig. 3 is a view showing a lower portion of the collected ash storage section.

Fig. 4 is a cross-sectional view showing the feed conveyor.

FIG. 5 is a graph showing deliquescence conditions of calcium chloride.

Fig. 6 is a view showing another example of the exhaust gas treatment device.

Description of the reference numerals

1. Incineration plant

2. Combustion chamber

3. Flue duct

4. 4a waste gas treatment device

42. Medicine supply unit

43. Dust collector

44. Dust collecting and conveying part

46. 46a feed conveyor

47. Heating part for collecting dust

48. Vibration part for collecting dust

441. Auxiliary path

442. Dust collecting and storing part

444. Chute part

445. Crushing part

465. Holding part

P1 medicine supply position

P2, P2a dust collecting ash supply position

Detailed Description

Fig. 1 is a diagram showing a structure of an incineration facility 1 according to an embodiment of the present invention. The incineration facility 1 is a facility for incinerating waste such as municipal waste. The incineration plant 1 is provided with a combustion chamber 2, a flue 3, an exhaust gas treatment device 4, a guiding ventilator 51 and a chimney 52. The combustion of the refuse is performed in the combustion chamber 2, and the combustion of the combustible gas generated from the refuse is performed. The flue 3 connects the combustion chamber 2 with a stack 52. The exhaust gas treatment device 4 and the guide ventilator 51 are provided in the flue 3. The guide ventilator 51 discharges the exhaust gas (combustion gas) generated in the combustion chamber 2 to the flue 3, and guides the exhaust gas to the stack 52 by the exhaust gas treatment device 4. That is, the exhaust gas having the combustion chamber 2 as a generation source flows from the combustion chamber 2 toward the chimney 52 in the flue 3, and the exhaust gas is subjected to a predetermined treatment by the exhaust gas treatment device 4. The stack 52 releases the exhaust gases to the atmosphere. The flue 3 is shown in fig. 1 by a thick solid line.

Fig. 2 is a diagram showing the structure of the exhaust gas treatment device 4. The exhaust gas treatment device 4 includes a cooling tower 41, a chemical supply unit 42, a dust collector 43, and a collected ash conveying unit 44. In the flue 3, a cooling tower 41, a chemical supply portion 42, and a dust collector 43 are provided in this order from the combustion chamber 2 toward the stack 52, that is, from the upstream side toward the downstream side in the flow direction of the exhaust gas. In practice, a denitration device or the like may be provided between the dust collector 43 and the chimney 52.

The cooling tower 41 sprays water into the exhaust gas flowing from the combustion chamber 2 to lower the temperature of the exhaust gas. The temperature of the exhaust gas discharged from the cooling tower 41 is, for example, about 170 ℃. The chemical supply unit 42 includes a slaked lime storage unit 421, a special auxiliary agent storage unit 422, a chemical pressure-feed unit 423, a chemical supply line 424, and

dosing units

425 and 426. One end of the chemical supply line 424 is connected to the chemical pressing unit 423, and the other end is connected to a position P1 (hereinafter referred to as "chemical supply position P1") between the cooling tower 41 and the dust collector 43 in the flue 3. The chemical presser 423 is a blower, and sends air to the stack 3 in the chemical supply line 424. The slaked lime storage 421 stores powdered slaked lime (calcium hydroxide (Ca (OH)) ₂ ) As a calcium (Ca) based agent. Slaked lime is a reagent for dechlorination and desulfurization. In slaked lime storageA dosing portion 425 is mounted on the lower part of the portion 421. The quantitative supply unit 425 is, for example, a table feeder, and takes out (separates) a predetermined amount of slaked lime from the slaked lime storage unit 421 per unit time. The dosing section 425 is connected to the chemical supply line 424, and supplies the slaked lime taken out from the slaked lime storage section 421 into the chemical supply line 424.

The special auxiliary agent storage unit 422 stores a powdery medicine (e.g., a reinforcing device (Bag-Ace) (registered trademark) and/or activated carbon, hereinafter referred to as "special auxiliary agent") manufactured by hitachi Kagaku corporation. A constant-volume supply unit 426 is attached to the lower part of the special auxiliary agent storage unit 422, and a predetermined amount of special auxiliary agent is taken out of the special auxiliary agent storage unit 422 per unit time. The quantitative supply unit 426 is connected to the medicine supply line 424, and supplies the special auxiliary agent taken out from the special auxiliary agent storage unit 422 into the medicine supply line 424. With the chemical supply unit 42 having such a structure, slaked lime and a special auxiliary agent (hereinafter, collectively referred to as "exhaust gas treatment chemical") are supplied (blown) into the flue 3 at the chemical supply position P1. The exhaust gas treatment agent may also contain dolomite hydroxide [ Ca (OH) ₂ ·Mg(OH) ₂ ]Other calcium-based agents (calcium-containing agents) instead of slaked lime, or containing slaked lime and dolomite hydroxide [ Ca (OH) ₂ ·Mg(OH) ₂ ]Other calcium-based agents (calcium-containing agents).

The dust collector 43 is, for example, a filter type, and removes fly ash contained in the exhaust gas by a filter cloth. The dust container 43 is also called a bag filter. The exhaust gas treatment agent supplied from the agent supply unit 42 is deposited on the filter cloth. In the dust collector 43, when the exhaust gas passes through the filter cloth, the harmful substances contained in the exhaust gas react with the exhaust gas treatment chemical to remove the harmful substances. The reaction of the exhaust gas with the exhaust gas treatment agent also occurs in the flue 3. The harmful substances removed by the exhaust gas treatment agent are, for example, hydrogen chloride, sulfur oxides, dioxins, mercury compounds, and the like. In the dust collector 43, fly ash and an exhaust gas treatment chemical (including a reaction product with a hazardous substance) deposited on the filter cloth are scraped off by back washing with compressed air at predetermined intervals. In the following description, fly ash and an exhaust gas treatment agent scraped off from the filter cloth are collectively referred to as "collected ash".The collected ash is a trap in the dust collector 43. Sodium bicarbonate (NaHCO) may be supplied to the medicine supply portion 42 ₃ ) Other types of chemicals such as activated carbon, and in this case, the other types of chemicals are also contained in the collected dust.

The collected ash conveying section 44 includes an auxiliary path 441, a collected ash distributing section 45, a collected ash storing section 442, a quantitative supply section 443, a supply conveyor 46, and a chute section 444. The auxiliary passage 441 connects the lower portion of the dust collector 43 to a position between the cooling tower 41 and the dust collector 43 in the flue 3 (hereinafter referred to as "collected ash supply position P2"). The auxiliary path 441 is shown in fig. 2 by a thin solid line. The auxiliary path 441 is a path different from the flue 3. In the auxiliary path 441, a collected ash distributing portion 45, a collected ash storing portion 442, a constant-volume supply portion 443, a supply conveyor 46, and a chute portion 444 are provided in this order from the dust collector 43 toward the collected ash supply position P2.

The collected ash distributing section 45 distributes and supplies the collected ash scraped off from the filter cloth in the dust collector 43 to the collected ash storing section 442 and the collected ash processing section 49. Specifically, the collected ash distributing section 45 includes a conveyor 451 and a shutter 452. The conveyor 451 is, for example, a scraper conveyor, and has the same structure as the supply conveyor 46 described later. The shutter 452 is provided on a conveying path for conveying the collected ash by the conveyor 451. When the stored amount of the collected dust obtained by a level meter (not shown) in the collected dust storage portion 442 is smaller than a predetermined amount, the shutter 452 is opened to supply the collected dust to the collected dust storage portion 442. When the stored amount of the collected dust in the collected dust storage portion 442 is equal to or greater than a predetermined amount, the shutter 452 is closed, and the collected dust is supplied to the collected dust processing portion 49. In this way, in the collected dust distributing section 45, the collected dust from the dust collector 43 is distributed to the collected dust storing section 442 and the collected dust processing section 49 by opening and closing the shutter 452 so that the stored amount of the collected dust in the collected dust storing section 442 is substantially constant. The collected dust supplied to the dust treatment section 49 is treated with, for example, a chelating agent (heavy metal stabilizer). Other conveyors and the like may be provided between the shutter 452 and the collected ash storage section 442.

Fig. 3 is a view showing a lower portion of the collected ash storage section 442. The exhaust gas treatment device 4 further includes a collected ash heating section 47 and a collected ash vibrating section 48. The collected ash heating section 47 has a plurality of heaters 471, and the plurality of heaters 471 are mounted on the outer side surface of the lower portion of the collected ash storage section 442. Each heater 471 heats the outer surface of the collected ash storage portion 442 by electricity. In this example, the collected ash stored in the collected ash storage section 442 is heated to 60 ℃ or higher, for example, by the collected ash heating section 47. The heating temperature of the collected ash is preferably 70℃or higher, more preferably 120℃or higher. Typically, the heating temperature of the collected ash is below the temperature of the exhaust gas in the dust collector 43 (e.g., 170 ℃). In the collected ash heating section 47, the collected ash may be heated by steam or the like from a boiler provided above the combustion chamber 2.

The collected ash vibrating portion 48 is mounted on the lower portion of the collected ash storage portion 442, as in the collected ash heating portion 47. The collected ash vibrating section 48 intermittently or continuously vibrates the vicinity of the portion of the collected ash storage section 442 heated by the collected ash heating section 47. This allows the collected ash located near the inner side surface of the lower part of the collected ash storage section 442 to be replaced, and the collected ash in the collected ash storage section 442 to be efficiently heated.

As shown in fig. 2, a quantitative supply portion 443 is attached to the lower portion of the collected ash storage portion 442. The quantitative supply unit 443 is, for example, a table feeder, and takes out a predetermined amount of collected ash from the collected ash storage unit 442 per unit time. The quantitative supply portion 443 is connected to the supply conveyor 46, and the collected ash taken out from the collected ash storage portion 442 is supplied into the supply conveyor 46.

Fig. 4 is a cross-sectional view showing the supply conveyor 46. The supply conveyor 46 is, for example, a scraper conveyor (also referred to as a scraper conveyor), and conveys the collected dust along a conveyor conveyance path from below the collected dust storage portion 442 to above the collected dust supply position P2 in the flue 3. The conveyor conveying path is part of the auxiliary path 441 described above. The supply conveyor 46 includes a housing 461, a pair of endless chains 462, a plurality of scrapers (scrapers) 463, and a plurality of sprockets 464 (see fig. 2). The housing 461 is disposed along the conveyor conveying path. The pair of endless chains 462 are arranged to be separated from each other by a predetermined distance in a direction perpendicular to the paper surface of fig. 4 (hereinafter referred to as "width direction"). Each endless chain 462 is engaged with a sprocket 464 disposed below the collected ash storage section 442 and a sprocket 464 disposed near the upper side of the collected ash supply position P2 in the housing 461. The pair of endless chains 462 continuously rotate (circulate) in the housing 461 by rotation of the sprocket 464 driven by a driving portion (not shown). In practice, sprockets are also provided at positions where the direction of the conveyor transport path changes.

A plurality of blades 463 are fixed to a pair of endless chains 462 at predetermined intervals. Each scraper 463 is a substantially rectangular plate member, and is fixed to a pair of endless chains 462 at both ends along one side in the width direction. In the forward passage from below the collected ash storage portion 442 toward above the collected ash supply position P2, the tip end (the side opposite to the fixed portion fixed to the endless chain 462) of each scraper 463 slides on the bottom surface portion of the housing 461. Further, the remaining two sides of the blade 463 are close to both side face portions (side face portions perpendicular to the width direction) of the case 461. Therefore, in the supply conveyor 46, a space between two blades 463 adjacent to each other along the conveyor conveying path becomes a holding portion 465 capable of accommodating the collected ash. In this way, the supply conveyor 46 has a plurality of holding portions 465 provided along the auxiliary path 441.

An inlet opening is provided in a position facing the quantitative supply portion 443 in the upper surface portion of the housing 461, and the collected ash falling from the quantitative supply portion 443 is supplied into the supply conveyor 46 through the inlet opening. The collected ash is stored in the holding portion 465 in the form of a block 9, and is transported to above the collected ash supply position P2 in the flue 3. An outlet opening is provided in a bottom surface portion of the housing 461 at a position opposed to the collected ash supply position P2, through which the collected ash is discharged to the outside of the supply conveyor 46. The chute portion 444 is provided above the collected ash supply position P2 in the flue 3 and connected to the outlet opening. Thereby, the collected ash stored in each holding portion 465 is thrown down to the chute portion 444, and the chute portion 444 extends vertically downward from the outlet opening.

As shown in fig. 2, a shutter 446 and a pulverizing portion 445 are preferably provided in the chute portion 444. The pulverizing unit 445 is, for example, a metal mesh or a metal member provided in a lattice shape, and pulverizes the collected ash by colliding with the collected ash thrown from the supply conveyor 46. The chute portion 444 is opened at a collected ash supply position P2 of the flue 3, and pulverized collected ash is dispersed into the exhaust gas flowing through the flue 3 at the collected ash supply position P2. During the transport of the collected ash along the auxiliary path 441, the shutter 446 is in principle in an open state. The pressure in the housing 461 is higher than the pressure in the flue 3, preventing exhaust gas from flowing into the housing 461. In addition, the shutter 446 may be closed when the conveyance of the collected ash is stopped or the like.

In the collected ash conveying section 44, the quantitative supply section 443 connected to the lower portion of the collected ash storage section 442 is formed to have a surrounding structure. The connection portion connecting the dosing portion 443 to the inlet opening of the housing 461 is also surrounded by the periphery. The housing 461 is sealed except for the inlet opening and the outlet opening, and the chute portion 444 connecting the outlet opening of the housing 461 to the flue 3 is also formed in a surrounding structure. As described above, in the auxiliary passage 441, the portion between the collected ash storage portion 442 and the flue 3 is a closed space in which the outside air hardly enters.

The connection portion connecting the collected dust storage portion 442 and the collected dust distribution portion 45 is formed to be surrounded by the periphery, and the collected dust distribution portion 45 connected to the lower portion of the dust collector 43 is also formed to be surrounded by the periphery. Therefore, in the auxiliary passage 441, a portion between the dust collector 43 and the dust storage portion 442 also becomes a closed space in which the outside air hardly enters. In addition, according to the configuration of the collected ash conveying section 44, the pressure in the collected ash storage section 442 to which collected ash is sequentially supplied becomes positive pressure higher than the atmospheric pressure. In this case, a mechanism may be provided for discharging the gas in the collected ash storage section 442 to the outside through a predetermined filter. In this case, since the inside of the collected ash storage portion 442 is positive pressure, the outside air does not enter the collected ash storage portion 442.

Here, the collected ash contains calcium chloride, which is a reaction product of hydrogen chloride in the exhaust gas and slaked lime contained in the exhaust gas treatment agent. When the exhaust gas treatment chemical contains other calcium-based chemicals such as dolomite hydroxide, the collected ash also contains calcium chloride. Fig. 5 is a graph showing deliquescence conditions of calcium chloride in exhaust gas. In fig. 5, the region above the line L1 is a dry region where no deliquescence occurs, the region between the two lines L1 and L2 is a partial deliquescence region where partial deliquescence occurs, and the region below the line L2 is a deliquescence region where substantially all deliquescence occurs. As can be seen from fig. 5, deliquescence of calcium chloride is likely to occur as the temperature becomes lower.

Next, an exhaust gas treatment device of a comparative example in which collected ash is returned to the flue 3 by using external air or treated exhaust gas will be described. In the exhaust gas treatment device of the comparative example, the collected ash is cooled by the carrier gas, which is external air or treated exhaust gas, and calcium chloride contained in the collected ash deliquesces. Thereby, the collected ash adheres to the inner surface of the pipe for returning the collected ash to the flue 3. As a result, when the diameter of the pipe is small, the collected ash cannot be properly returned to the flue 3.

In contrast, in the exhaust gas treatment device 4 of fig. 2, the auxiliary passage 441 for returning the collected ash to the flue 3 is provided with a collected ash conveying portion 44 and a collected ash heating portion 47. The collected dust collected by the dust collector 43 can be conveyed to the collected dust supply position P2 in the flue 3 along the auxiliary path 441 without using outside air, treated exhaust gas, or the like by the collected dust conveying section 44. In addition, the collected dust is heated in the auxiliary path 441 by the collected dust heating portion 47. This can suppress deliquescence of calcium chloride contained in the collected ash, and can suppress adhesion of the collected ash in the auxiliary path 441. In the exhaust gas treatment device of the comparative example, a blower or the like for the carrier gas may be omitted. Since the blower is expensive, the blower can be omitted, and thus the manufacturing cost of the exhaust gas treatment device 4 can be reduced. In the incineration equipment 1 with the exhaust gas treatment device 4, the operation cost can be reduced by reusing the exhaust gas treatment agent contained in the collected ash, and stable operation can be realized.

The supply conveyor 46 of the collected dust conveying unit 44 conveys the plurality of holding units 465 for holding the collected dust along the auxiliary path 441, thereby supplying the collected dust to the collected dust supply position P2. In the supply conveyor 46 that accommodates the collected dust in the holding portion 465, a temperature drop of the collected dust during conveyance can be suppressed as compared with a screw conveyor or the like that conveys the collected dust while stirring. As a result, adhesion of the collected ash in the auxiliary path 441 can be further suppressed. In the collected dust conveying section 44, the auxiliary passage 441 is a passage having a structure in which outside air does not enter, so that the temperature of the collected dust during conveyance can be further suppressed from decreasing, the moisture concentration of the surrounding gas can be prevented from increasing, and the adhesion of the collected dust in the auxiliary passage 441 can be further suppressed. In the collected ash conveying section 44, another kind of conveyor that does not stir the collected ash may be used as the supply conveyor 46. Further, a screw conveyor or the like for stirring the collected ash may be used as the supply conveyor 46 depending on the heating temperature of the collected ash heating section 47 or the like.

The collected ash is thrown from the supply conveyor 46 to the chute portion 444, and the collected ash is easily dispersed in the flue 3 by providing the pulverizing portion 445 that collides with the collected ash to pulverize the collected ash in the chute portion 444. Thus, the exhaust gas treatment performance can be improved.

The collected ash heating section 47 heats the collected ash storage section 442 in which the collected ash is stored, thereby efficiently heating the collected ash. In addition, by vibrating the vicinity of the portion of the collected ash storage portion 442 heated by the collected ash heating portion 47 by the collected ash vibrating portion 48, not only adhesion of the collected ash in the collected ash storage portion 442 is suppressed, but also a wide range of the collected ash in the collected ash storage portion 442 can be efficiently heated. Depending on the design of the exhaust gas treatment device 4, the collected ash heating section 47 may be provided in a position other than the collected ash storage section 442 in the auxiliary passage 441.

Fig. 6 is a view showing another example of the exhaust gas treatment device. In the exhaust gas treatment device 4a of fig. 6, another supply conveyor 46a is added to the exhaust gas treatment device 4 of fig. 2, so that the collected ash can be supplied to a position P2a (hereinafter referred to as a "second collected ash supply position P2 a") between the combustion chamber 2 and the cooling tower 41 in the flue 3. The supply conveyor 46a has the same structure as the supply conveyor 46. Other structures are the same as in fig. 2, and the same reference numerals are given to the same structures.

In the exhaust gas treatment device 4a, a second outlet opening is provided in the bottom surface portion of the housing 461 at the middle of the conveyance path extending in the horizontal direction in the supply conveyor 46. The second outlet opening is provided with a connection portion including a shutter 469, and the collected dust in the holding portion 465 (see fig. 4) is discharged to the outside of the supply conveyor 46 via the connection portion in a state where the shutter 469 is opened. An inlet opening is provided in an upper surface portion of the housing 461 of the supply conveyor 46a at a position opposed to the connecting portion, and the collected dust discharged from the supply conveyor 46 is supplied into the supply conveyor 46a through the inlet opening.

The collected ash is conveyed upward above the second collected ash supply position P2a in the flue 3 in a state of being accommodated in the holding portion 465 (see fig. 4) of the supply conveyor 46 a. An outlet opening is provided in a bottom surface portion of the housing 461 at a position opposed to the second collected ash supply position P2a, and collected ash is discharged to the outside of the supply conveyor 46a through the outlet opening. The chute portion 444 extending vertically downward is connected to the outlet opening, and the collected ash is supplied to the second collected ash supply position P2a in the flue 3 via the chute portion 444.

As described above, in the exhaust gas treatment device 4a, the collected ash is supplied to the second collected ash supply position P2a in addition to the collected ash supplied to the collected ash supply position P2. Here, the solubility of the reaction product formed on the surface of the slaked lime with hydrogen chloride in water is large, and when the slaked lime is supplied into the cooling tower 41, the reaction product is dissolved in the water sprayed into the cooling tower 41 and washed away, that is, the reaction product is removed from the surface of the slaked lime. This makes unreacted slaked lime exposed to the surface, and suppresses a decrease in reaction rate due to reaction products of slaked lime. Therefore, in the exhaust gas treatment device 4a that supplies the collected ash to the position (the second collected ash supply position P2 a) between the combustion chamber 2 and the cooling tower 41 in the flue 3, the efficiency of the dechlorination reaction can be improved. The same applies to the case where the exhaust gas treatment chemical contains another calcium-based chemical such as dolomite hydroxide, and the reaction product with hydrogen chloride formed on the surface of the other calcium-based chemical is removed by water sprayed into the cooling tower 41, thereby suppressing a decrease in the reaction rate of the other calcium-based chemical. In the exhaust gas treatment device 4 of fig. 2, the same applies to the case where the collected ash supply position P2 is set at a position between the combustion chamber 2 and the cooling tower 41 in the flue 3.

The incineration plant 1 and the exhaust gas treatment devices 4, 4a described above may be subjected to various variants.

In the exhaust gas treatment devices 4 and 4a, the supply of the exhaust gas treatment chemical at the chemical supply position P1 and the supply of the collected ash at the collected ash supply positions P2 and P2a are not always required, and one of them may be temporarily stopped.

The medicine supply position P1 may be set between the combustion chamber 2 and the cooling tower 41, for example. That is, the medicine supply position P1 may be set between the combustion chamber 2 and the dust collector 43 in the flue 3.

The exhaust gas treatment devices 4, 4a may be applied to equipment other than the incineration equipment 1.

The configurations of the above-described embodiment and the modifications can be appropriately combined without contradiction.

The invention has been described and illustrated in detail, but the foregoing description is intended to be illustrative and not limiting. Accordingly, various modifications and arrangements may be made without departing from the scope of the invention.

Claims

1. An exhaust gas treatment device, comprising:

the dust collector is arranged on the flue for circulating the waste gas;

a chemical supply unit configured to supply an exhaust gas treatment chemical to a chemical supply position between the dust collector and the source of exhaust gas generated in the flue;

a collected dust conveying unit that conveys collected dust collected by the dust collector to a collected dust supply position between the generation source and the dust collector in the flue along an auxiliary path different from the flue by a conveyor; and

a dust collection heating part arranged on the auxiliary path for heating the dust collection,

the conveyor may comprise a housing that includes a plurality of conveyor belts,

the pressure in the housing is higher than the pressure in the flue, preventing the exhaust gas from flowing into the housing,

the conveyor has a plurality of holding portions provided along the auxiliary path and accommodating the collected ash in a block state in the housing, and conveys the plurality of holding portions along the auxiliary path.

2. The exhaust gas treatment device according to claim 1, wherein,

the housing has an inlet opening and an outlet opening,

the collected ash is fed into the conveyor via the inlet opening, the outlet opening being opposite to the collected ash feed position, the housing being closed except for the inlet opening and the outlet opening.

3. The exhaust gas treatment device according to claim 1, wherein the exhaust gas treatment agent comprises a calcium-based agent.

4. The exhaust gas treatment device according to claim 1, wherein,

the collected ash conveying part comprises a chute part,

the housing has an outlet opening opposite the collected ash feed location,

the chute portion is connected with the outlet opening of the housing and opens into the flue,

the collected dust accommodated in each holding portion is thrown down to the chute portion.

5. The exhaust gas treatment device according to claim 4, wherein,

the collected ash conveying part further includes:

a crushing unit configured to crush the collected ash by colliding with the thrown-in collected ash in the chute unit; and

a shutter which can be opened and closed and is arranged in the chute part,

during the transport of the collected ash along the auxiliary path, the shutter is in an open state, and the pressure in the housing is higher than the pressure in the flue, preventing the exhaust gas from flowing into the housing.

6. The exhaust gas treatment device according to any one of claims 1 to 5, wherein,

the dust collecting ash conveying part comprises a dust collecting ash storing part which is arranged on the auxiliary path and stores the dust collecting ash,

the collected dust heating part heats the collected dust in the collected dust storing part,

the quantitative supply part takes out the set quantity of the collected dust from the collected dust storage part every unit time and supplies the collected dust into the conveyor.

7. The exhaust gas treatment device according to claim 6, further comprising a collected ash vibrating portion that vibrates a vicinity of a portion of the collected ash storage portion heated by the collected ash heating portion.

8. An incineration apparatus, characterized by comprising:

a combustion chamber for burning waste;

a flue that discharges exhaust gas generated in the combustion chamber from the combustion chamber; and

the exhaust gas treatment device according to any one of claims 1 to 7, provided in the flue.