JP3759154B1 - Exhaust gas denitration device, integrated filtration dust collector equipped with the device, and exhaust gas treatment facility - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an exhaust gas denitration device and an integrated filtration dust collecting device having a simple device configuration, capable of reducing the size and space of the device, and maintaining high denitration performance without causing problems such as liquid dripping or blocking of an ammonia supply hole. Providing equipment and exhaust gas treatment equipment that can reduce running costs by reducing chemical usage.
SOLUTION: In an integrated filter dust collector 20 that simultaneously removes dust, nitrogen oxides, and organic halogen compounds, a filter cloth 24 and a catalyst layer 16 are sequentially disposed in the apparatus main body 21, and the filter cloth and the catalyst layer are arranged. The ammonia supply unit 12 is provided between the ammonia supply unit 13 and the ammonia supply unit 13. The ammonia supply unit 13 supplies the ammonia solution 30 and the heat transfer area for vaporizing the ammonia solution supplied from the supply tube by sensible heat of the exhaust gas. A baffle plate 15 is provided between the ammonia supply unit 12 and the catalyst layer 16 to disperse the ammonia gas evaporated from the tray 14 in the exhaust gas.
[Selection] Figure 2

Description

The present invention, waste incinerators, gasification furnace, relates exhaust gas denitration apparatus for removing nitrogen compounds of the NO _x or the like contained in the exhaust gas discharged from the combustion apparatus of the melting furnace or the like, further dust with nitrogen compounds, acidic The present invention relates to an integrated filter dust collector capable of simultaneously removing gases and harmful substances such as organic halogen compounds, and an exhaust gas treatment facility equipped with these devices.

Waste incinerators, gasification furnace, the flue gas discharged from the combustion apparatus of the melting furnace or the like, high concentrations of dust, acidic gases such as SO _x and HCl, nitrogen oxides such as NO _x, and polyhalogenated There are many harmful substances such as dibenzoins such as dibenzodioxin, polyhalogenated dibenzofuran, polyhalogenated biphenyl, and organic halogen compounds such as halogenated benzene, halogenated phenol, and halogenated toluene that are precursors of dioxins. . Conventionally, in order to detoxify and stabilize these harmful substances, the exhaust gas treatment facility is provided with a plurality of treatment apparatuses corresponding to the respective harmful substances.

Among these processing units, as denitration process for removing nitrogen oxides in the exhaust gas, after the catalyst by SO _x remaining after dust collection was reheated exhaust gas to a temperature not poisoned, the exhaust gas catalyst tower A method of introducing and denitrating is generally used. At this time, ammonia is injected into the exhaust gas within or a pre-stage catalyst column, by passing the exhaust gas to the catalyst in an ammonia coexist, the NO _x in the exhaust gas were decomposed into nitrogen and water.
Conventional ammonia supply methods include (1) a method in which ammonia liquid is directly sprayed on exhaust gas, (2) a method in which gaseous ammonia previously vaporized is sprayed, and (3) a gaseous state by vaporizing ammonia liquid in an exhaust gas duct. A method of spraying ammonia can be mentioned.

(1) In the method of spraying ammonia liquid directly on exhaust gas, the ammonia liquid is sprayed directly from a nozzle provided in the duct. However, this method requires an evaporation space in the duct, which may increase the size of the apparatus, and causes problems of non-evaporation and performance deterioration due to gas nonuniformity. Furthermore, dripping due to unevaporated ammonia occurs, and the equipment is corroded. Furthermore, there is a possibility that the nozzle is clogged by soot and acidic ammonium sulfate produced by the reaction with SO _x in the exhaust gas.

  (2) As a method of spraying gaseous ammonia previously vaporized by an external heating device, the ammonia liquid is vaporized by an electric heater in advance and then sprayed from a nozzle (Patent Document 1). A method of spraying ammonia liquid into a duct from a nozzle after heating and vaporization (Patent Document 2), A method of spraying ammonia liquid into a duct from a nozzle after vaporizing in advance (Patent Document 3), and operation using a steam ejector There is a method of spraying gaseous ammonia while vaporizing ammonia liquid using water vapor as a fluid, or spraying in a gas-liquid mixed phase flow (Patent Document 4).

As described above, in the method of spraying gaseous ammonia that has been vaporized in advance, mixing and uniformity with the exhaust gas is good, but in order to sufficiently vaporize the ammonia liquid that is normally handled in advance, a separate ammonia vaporization facility is installed. This necessitates an increase in equipment installation space.
Further, when heating using an electric heater as in Patent Document 1, there is a problem that running cost increases because it is necessary to use electric power separately.
When exhaust gas is partially extracted and used for vaporization as in Patent Document 2, there is a concern about clogging of the nozzle due to the formation of acidic ammonium sulfate when vaporizing the ammonia liquid, and responsiveness to changes in the evaporation amount is expected. There was a problem of being slow.
Further, when vaporizing by steam heating as in Patent Document 3, since steam recovered from the combustion apparatus is used, there is a problem that the amount of steam that can be used for power generation is reduced and the amount of power generation is reduced. .
Further, when a steam ejector is used as in Patent Document 4, an ammonia vaporization facility is not required. However, since the amount of power generation is reduced due to the use of water vapor, ammonia is sprayed as an ammonia liquid without being completely vaporized. Liquid dripping from the supply hole may cause problems such as equipment corrosion. When there is a dust collector in the lower part due to the integration of the dust collector, there is a possibility that the filtration unit is blocked. Further, when ammonia reaches the catalyst in the form of droplets, there is a problem that ammonia mixing in the exhaust gas is insufficient and the denitration performance is lowered.

  (3) As a method of vaporizing the ammonia liquid in the duct, the ammonia liquid supplied into the duct is vaporized through a tube, and then sprayed from a nozzle (Patent Document 5). A method of spraying ammonia liquid by using ammonia heat pipes and connecting pipes connecting them, vaporizing ammonia liquid using waste heat of some exhaust gas, and a porous ceramic tube in the duct There is a method (Patent Document 7) of supplying ammonia liquid to the gas and evaporating it in a duct.

However, in the method of vaporizing in the tube as in Patent Document 5, when the exhaust gas temperature is lowered due to the start and stop of the combustion device or due to fluctuations, droplet dropping from the ammonia supply nozzle occurs, causing corrosion of the equipment and catalyst May cause problems such as elution.
Further, in the method of partially vaporizing with exhaust gas as in Patent Document 6, the structure is complicated because a vaporizer, ammonia injection means, and a connecting pipe are installed in the duct, and the gas flow upstream side of the ammonia injection means Space is required, and the entire device cannot be made compact.
Further, in the method using a porous ceramic tube as in Patent Document 7, the nozzle is blocked due to the production of acidic ammonium sulfate.

On the other hand, in a general process in an exhaust gas treatment facility equipped with such a denitration device, first, high-temperature exhaust gas discharged from a combustion device is cooled to a predetermined temperature by water spraying in a temperature reducing tower, and then by slaked lime spraying. After removing acidic gases such as HCl and SOx, the dust in the exhaust gas is collected by a bag filter, an electrostatic precipitator, etc., and then the temperature of the exhaust gas is raised by a reheater. In this way, denitration and dioxin were decomposed and removed.
However, in such an exhaust gas treatment facility, there is a problem that a new installation space is required for the installation of the reheater and the catalyst tower, and the heat energy required for the reheating is lost and a great cost is required. .

Therefore, Patent Document 8 proposes an apparatus configuration in which a dust collector and a catalyst tower are integrated. In this dust collector, an exhaust gas to which an auxiliary agent, an absorbent and a reducing agent are added is introduced into the dust collector, firstly collected by a bag filter in the device, and then exhausted by a denitration catalyst layer provided thereabove. Denitration is performed.
However, when ammonia is introduced as a reducing agent upstream of the bag filter, ammonia is adsorbed on the dust layer on the surface of the bag filter, causing a loss in denitration, and the collected dust gives off an ammonia odor. Was. Furthermore, as in Non-Patent Document 1, if ammonia is supplied immediately before the catalyst integrated with the dust collector, the residence time is short, so the ammonia concentration distribution becomes non-uniform and the denitration performance deteriorates. It becomes. In particular, when ammonia is supplied as a liquid, it will not vaporize sufficiently and will reach the catalyst as droplets, causing extreme performance degradation. In some cases, there is a possibility of clogging the filtration part.

Another problem with the exhaust gas treatment equipment is that in the acid gas removal process, acid gas removal with slaked lime has low removal performance, so it is necessary to put in a large amount, and the chemical cost is high and the amount of fly ash treatment is large, ash treatment There was a problem of high costs. Furthermore, in order to prevent the poisoning deterioration of the catalyst due to the remaining SO _x, it is necessary to install a temperature raising device in front of the catalyst, the entire system becomes huge, the device installation space increases, the equipment cost increases and the running cost also increases. It was expensive.
Therefore, Patent Document 9 uses a Na-based acid gas remover that has high acid gas removal performance and can reduce chemical costs and ash treatment costs. Sodium hydroxide, which is a typical Na-based acid gas remover, is used. In sodium bicarbonate or sodium hydrogen carbonate, reactive products and unreacted substances become very fine particles after spraying, causing clogging in the bag filter, which is a dust collector, and having deliquescence. Pressure loss increased, the service life was shortened, and bag filter protective agents (diatomaceous earth, etc.) had to be sprayed in large quantities.
Further, when spraying the Na-based acid gas removal agent and hydrated lime, can not follow the SO _x concentration change in the exhaust gas, the residual SO _x concentration is increased, or accelerated deterioration of the subsequent catalyst, excess conversely Na-based acid removal agent and slaked lime were supplied, and there was a concern that the drug cost would increase.

JP 2000-146147 A JP-A-7-16431 JP 2001-286735 A Japanese Utility Model Publication No. 4-9630 JP-A-7-265660 JP 2004-261762 A Japanese Utility Model Publication No. 3-86030 JP-A-5-217 Japanese Patent Laid-Open No. 2004-866 Proceedings of the 8th Annual Meeting of Japan Society of Waste Management. 1997.10; 569-571

Therefore, in view of the above-mentioned problems of the prior art, the present invention can reduce the size and space of the device with a simple device configuration, corrode the equipment due to ammonia dripping, and the ammonia supply hole due to dust and ammonium sulfate. Exhaust gas denitration equipment that can maintain high denitration performance without causing problems such as clogging, and this equipment, and simultaneously remove harmful substances such as dust, acid gas, and organic halogen compounds together with denitration An object of the present invention is to provide an integrated filtration dust collecting apparatus capable of
Furthermore, while achieving the above-mentioned object, the amount of the acid gas remover and filter cloth protective agent can be reduced, the running cost can be reduced, and the harmful substances in the exhaust gas can be efficiently removed. An object of the present invention is to provide an exhaust gas treatment facility capable of extending the life of a catalyst without using a catalyst.

Therefore, in order to solve the problem, the present invention provides an exhaust gas denitration apparatus including a catalyst unit that removes nitrogen compounds in exhaust gas, and an ammonia supply unit that is disposed in a gas flow channel upstream of the catalyst unit. In
The ammonia supply unit is disposed below the ammonia liquid supply pipe and an ammonia liquid supply pipe for supplying the ammonia liquid into the gas flow path, and the ammonia liquid supplied from the ammonia liquid supply pipe is exposed to the exhaust gas. Ammonia liquid vaporizing section, which is composed of a saucer formed so as to be vaporized by heat, and extends and arranged in the transverse cross-sectional direction perpendicular to the gas flow,
An exhaust gas dispersion part for dispersing ammonia gas vaporized from the ammonia liquid vaporization part in the exhaust gas;
The ammonia vaporization part and the exhaust gas dispersion part are arranged in the apparatus main body along the flow direction of the gas flow from the bottom to the top,
The tray that forms the ammonia liquid vaporizing section is arranged to extend in the transverse cross-sectional direction in the tank perpendicular to the gas flow.
In this case, the exhaust gas denitration apparatus according to claim 1, wherein nitrogen compounds contained in the exhaust gas discharged from the waste incinerator, gasification furnace or melting furnace are removed together with dioxin.
The shape of the catalyst used for the catalyst part is preferably a pellet.
In addition, an exhaust gas dispersion unit that disperses the ammonia gas evaporated from the ammonia liquid tray in the exhaust gas may be provided in a gas flow path between the ammonia supply unit and the catalyst unit.
Furthermore, it is preferable that the exhaust gas dispersion part is formed of a baffle plate having an exhaust gas ventilation part.
Furthermore, the exhaust gas dispersion part has a structure in which a baffle plate having an exhaust gas ventilation part is laminated in a plurality of stages at intervals along the flow direction of the gas flow from below to above,
The first baffle plate located on the lower side of the gas flow upstream is formed with the exhaust gas vent so that the exhaust gas is mixed, and the second baffle plate located on the downstream side of the gas flow is It is preferable that an exhaust gas ventilation part is formed so as to cover the exhaust gas ventilation part of the first baffle so that the exhaust gas is rectified.

In the present invention, ammonia liquid is not vaporized in advance or a vapor ejector or the like is used, and is supplied as it is to an ammonia liquid vaporizing section consisting of an ammonia receiving tray in a gas flow path by a pump or the like, and the receiving tray is used by utilizing sensible heat of exhaust gas. The ammonia liquid is vaporized to form ammonia gas.
In contrast to the case where the ammonia liquid is supplied after being vaporized, it is not necessary to separately install an ammonia vaporization facility outside, so that the apparatus can be simplified and the apparatus can be reduced in size and space. Further, since an external heat source such as an electric heater is not required, the running cost can be reduced, and since steam is not used, steam generated in the combustion facility can be sent to power generation. Furthermore, since no dripping occurs, problems such as corrosion of equipment can be avoided, and the ammonia liquid supply hole is not easily blocked, so that stable denitration processing can be performed. Furthermore, since the baffle plate is provided, the ammonia gas and the exhaust gas are sufficiently mixed, so that the denitration performance can be improved.

Further, in the exhaust gas denitration apparatus, the ammonia liquid vaporizing section is a dish-shaped receiving tray,
The tray extends in the cross-sectional direction in the tank perpendicular to the gas flow, and the area ratio of the gas channel cross section of the ammonia liquid tray to the cross sectional area of the gas flow channel is 2 to 2 It is made to be in the range of 80%, and preferably the area ratio is in the range of 2 to 50%.
This is because if the area ratio is 2% or less, the minimum heat transfer area required for vaporization of the ammonia liquid cannot be secured, and if the area ratio is 80% or more, This is because an excessive increase in pressure loss exceeding the pressure loss occurs, preventing smooth operation of the denitration apparatus. Further, when the area ratio is in the range of 2 to 50%, the superficial velocity is set to an appropriate value, which is preferable.

Further, the ammonia liquid receiving tray is disposed so as to be inclined with a side away from the ammonia liquid supply hole of the ammonia liquid supply pipe facing downward.
As a result, the ammonia liquid dripped from the ammonia supply hole can quickly flow over the entire surface of the tray, and the ammonia liquid can be uniformly vaporized from the entire surface of the tray, improving the dispersibility of the ammonia gas in the exhaust gas. It becomes possible.

In addition, as the inventions that put to the integrated filtration dust collector,
An integrated filtration dust collector equipped with an exhaust gas denitration device in the device body,
In the apparatus main body, a dust collecting part is provided below the ammonia liquid vaporizing part. And

  As described above, according to the present invention, the dust collector and the denitration device are integrated to reduce the size and space of the device, and since the baffle plate is provided, the ammonia concentration distribution in the exhaust gas is made uniform. Thus, it is possible to improve the NOx removal performance and eliminate the odor of ammonia from the dust collected by the dust collector.

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Furthermore, it is an exhaust gas treatment facility provided with the integrated filtration dust collector of the invention according to claim 6 ,
An acidic gas removing agent introducing means for introducing a deliquescent acidic gas removing agent into the exhaust gas and a slaked lime introducing means for introducing slaked lime into the exhaust gas are provided on the upstream side of the integrated filtration dust collector in the exhaust gas flow direction. ,
The slaked lime is introduced as a powder or a slurry.
Here, the acid gas removing agent is, for example, sodium chemicals such as sodium hydroxide (NaOH), sodium bicarbonate (NaHCO ₃ ), sodium carbonate (Na ₂ CO ₃ ), potassium hydroxide (KOH), potassium hydrogen carbonate ( KHCO ₃ ) and potassium carbonate (K ₂ CO ₃ ).

According to the present invention, by introducing an acid gas removing agent having deliquescence and slaked lime into exhaust gas, the amount of chemicals used can be reduced, and the amount of fly ash collected by the subsequent dust collector can be greatly reduced. Drug costs and ash treatment costs can be reduced. Further, the need to place the reheater necessary suppressing deterioration of the catalyst can be reduced SO _x concentration is poisoning substance of the catalyst is eliminated, acidic ammonium sulfate also in the ammonia supply unit according to a porous material such as No clogging due to precipitation.
This is because an acid gas removing agent having high deliquescence properties with high reaction efficiency with acid gas is added to the case where only slaked lime that requires several times the amount (molar ratio) of acid gas is used as the acid gas removing agent. As a result, a high acid gas removal performance can be obtained in addition to a reduction in the total amount of medicine used.
In addition, the deliquescent acid gas removal agent is a substance that has deliquescence and the reaction product and unreacted substances after spraying become very fine particles. However, in the present invention, the slaked lime contributes to the acid gas removal performance by spraying slaked lime, although a large amount of auxiliary agent as a filter cloth protective agent (diatomaceous earth, etc.) had to be sprayed. However, since it plays a role as a filter cloth protective agent, the amount of the auxiliary spray for protecting the filter cloth can be remarkably reduced or it becomes unnecessary to spray, so that the acid gas can be efficiently removed at low cost.

As a method of supplying the deliquescent acid gas removing agent and slaked lime, after supplying the deliquescent acid gas removing agent, the slaked lime may be supplied in the subsequent stage, or after supplying the slaked lime, the deliquescent acid gas A removing agent may be supplied, or further, these may be supplied simultaneously. In the case of supplying slaked lime at a later stage after supplying an acid gas removing agent having deliquescence, an acidic gas effective by providing a process in which the acid gas removing agent having high acid gas removal performance absorbs acid gas is provided. Removal is possible.
On the other hand, when supplying an acid gas remover having deliquescence after supplying slaked lime, especially when the acid gas concentration is high, the removal performance is low, but after removing the acid gas with cheap slaked lime, the neutralization efficiency is high and removed. By spraying a small amount of acid gas removal agent having excellent deliquescence with excellent performance and removing it to a predetermined concentration, it is possible to suppress an increase in drug cost and to remove acid gas economically and efficiently as a whole.

Moreover, when supplying simultaneously, the acid gas removal agent or slaked lime which has the deliquescent property supplied to the front | former stage can eliminate the process which absorbs acidic gas, and an apparatus arrangement becomes simple and an apparatus number reduces, and it becomes a compact installation.
In any case, the supply of slaked lime can be supplied as powder or slurry.
In this way, the supply of the acid gas removing agent having deliquescence and slaked lime improves the acid gas removal performance and suppresses the poisoning deterioration of the catalyst, so that it is not necessary to reheat the exhaust gas in the previous stage of the catalyst part. Therefore, a filtration dust collector in which the catalyst part is integrated with the dust collecting part can be suitably adopted, the initial cost can be reduced, and the reheating energy can be saved, so that the running cost can also be reduced.

  Furthermore, the acid gas removing agent introducing means is attached to a temperature reducing tower disposed upstream of the integrated filter dust collector, and the liquid acid gas removing agent and water are supplied to the exhaust gas in the temperature reducing tower. It is characterized by being sprayed on.

Here, the liquid acid gas removing agent and the water for temperature reduction may be sprayed from separate supply ports in the temperature reducing tower, or may be premixed and sprayed from one supply port. When spraying from separate supply ports, especially when the acid gas removal agent supply port becomes unusable due to troubles such as clogging, only water for reducing the temperature can be sprayed. Combustion devices such as a furnace, a gasification furnace, and a melting furnace can be continuously operated. Moreover, when premixed and sprayed from one supply port, the equipment is simplified, and the material load on the alkali is reduced by dilution, thereby reducing the cost. Furthermore, since the ratio of the water | moisture content with respect to an acidic gas removal agent increases by dilution, the state of the droplet after spraying is maintained for a long time, absorption of acidic gas is accelerated | stimulated, and acidic gas removal performance improves.
In this way, by spraying the acid gas removal agent having deliquescent properties in the temperature reducing tower, neutralization reaction with the acid gas is achieved without installing a new drug supply space or supply seat and with water intervening. Speed is further enhanced, drug usage is reduced, and costs are reduced.

Further, the exhaust gas flow direction downstream side of said integrated filtering dust collector, the continuously detected to detect means at least one of the SO _x concentration or the concentration of HCl in exhaust gas is provided, SO _x detected by the detecting means It is preferable to control at least one introduction amount of the acidic gas removing agent or the slaked lime based on at least one of the concentration and the HCl concentration. A SO ₂ concentration may be used as the SO _x concentration.
Thus, continuous monitoring of SO _x concentration or HCl concentration at a location downstream of the dust collector, acid gas removal agent having such deliquescent equal to or less than the predetermined SO _x concentration or HCl concentration and / or slaked lime spray amount By optimizing, there is no wasteful drug supply and the running cost can be reduced. Moreover, by monitoring either or simultaneously directly SO _x concentration or HCl concentration is correlated to the SO _x concentration after acid gas removal after acid gas removal, poisoning deterioration of the catalyst due to SO _x can be suppressed.

As described above, according to the exhaust gas denitration apparatus of the present invention, it is not necessary to install an ammonia vaporization facility outside, so that the apparatus can be simplified, and the apparatus can be reduced in size and saved in space. Moreover, since an external heat source is not required, a running cost can be reduced. Furthermore, since no dripping occurs, problems such as corrosion of equipment can be avoided, and the ammonia liquid supply hole is not easily blocked, so that stable denitration processing can be performed. Furthermore, since the baffle plate is provided, the ammonia gas and the exhaust gas are sufficiently mixed, and the denitration performance can be improved.
Further, in the exhaust gas denitration apparatus, the ammonia liquid is adjusted so that an area ratio of a cross section of the gas flow passage to the gas flow passage section of the ammonia liquid tray is within a range of 2 to 80%. As a result, a minimum heat transfer area required for vaporization of the catalyst can be secured, an excessive pressure loss increase exceeding the pressure loss of the catalyst portion can be prevented, and the apparatus can be stably operated.

In addition, by arranging the ammonia liquid tray in an inclined manner, the ammonia liquid can quickly flow over the entire surface of the tray, and the ammonia liquid can be vaporized uniformly from the entire surface of the tray.
Furthermore, according to the integrated filtration dust collector in which the denitration device is integrated with the filter medium, the device can be reduced in size and space-saving, and the baffle plate is provided, so that the ammonia concentration distribution in the exhaust gas can be made uniform. This makes it possible to improve the NOx removal performance and eliminate the odor of ammonia from the dust collected by the dust collector.
Furthermore, according to the integrated filter dust collector in which the ammonia supply part composed of a porous ammonia supply body and the filter medium are integrated, ammonia gas can be uniformly vaporized from the entire surface of the ammonia supply body, A uniform dispersion effect of ammonia is enhanced.

In addition, according to the exhaust gas treatment facility of the present invention, the addition of an auxiliary agent is unnecessary or significantly reduced, the introduction amount of the chemical that neutralizes the acidic gas in the exhaust gas is reduced, the chemical cost is reduced, and the dust collector As a result, it is possible to significantly reduce the amount of fly ash collected in the process, and to provide an exhaust gas treatment facility capable of reducing the ash treatment cost.
Furthermore, acidic reduces replacement or regeneration costs by prolonging the life of the catalyst to decrease SO _x concentration becomes catalyst poisoning by improving the gas removal performance can be a low-cost exhaust gas treatment system in total.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the components described in this embodiment are not intended to limit the scope of the present invention unless otherwise specified, but are merely illustrative examples. Not too much.
1 to 7 are diagrams relating to an exhaust gas denitration apparatus according to Embodiment 1 of the present invention, FIG. 8 is a view relating to an integrated filtration dust collector according to Embodiment 2 of the present invention, and FIGS. FIG. 12 and FIG. 13 are diagrams regarding an exhaust gas treatment facility according to Example 3 of the present invention, and FIG. 14 is an exhaust gas treatment according to Example 4 of the present invention. It is a figure regarding equipment.

Note that the exhaust gas to be treated in this example is exhaust gas discharged from a combustion facility equipped with a combustion furnace such as a waste incinerator, gasification furnace, melting furnace, etc., such as soot dust, SO _x and HCl acid gas, sulfur oxides such as NO _x, and polyhalogenated dibenzodioxins, polyhalogenated dibenzofurans, precursor comprising halogenated benzene of dioxins and dioxins such as polyhalogenated biphenyls, halogenated phenols, halogenated toluene The exhaust gas containing harmful substances such as organic halogen compounds such as organic halogen compounds is suitably treated.

FIG. 1 is a schematic sectional view of an exhaust gas denitration apparatus according to Embodiment 1 of the present invention. As shown in FIG. 1, the exhaust gas denitration apparatus 10 of the first embodiment includes an ammonia supply unit 12 including an ammonia liquid supply pipe 13 and an ammonia liquid tray 14 in the duct 11 from the upstream to the downstream of the exhaust gas flow. And a catalyst layer 16, and a baffle plate 15 is provided between the ammonia supply unit 12 and the catalyst layer 16.
In this embodiment, as shown in the figure, the apparatus is a vertical type, and the exhaust gas 31 flows from below to above, but the gas flow is formed from above to below. It is also possible to have a lateral flow configuration in which the gas flow is parallel to the ammonia liquid tray 14.

The ammonia supply unit 12 includes an ammonia supply pipe 13 that supplies an ammonia liquid 30 into the duct 11, and an ammonia liquid tray 14 that is provided below the ammonia supply pipe 14 and receives the ammonia supplied from the ammonia supply pipe 13. The
One or a plurality of the ammonia supply pipes 13 are provided, and the ammonia supply pipe 13 is provided with one or a plurality of ammonia supply holes.
The ammonia liquid tray 14 is formed such that at least a heat transfer area necessary for vaporizing the ammonia liquid stored on the tray is secured.

  FIG. 2 shows an example of the ammonia supply unit. 2A is composed of one ammonia supply pipe 13 having one ammonia supply hole and one ammonia liquid receiving tray 14 having a square shape, and FIG. 2B is one ammonia supply pipe having one ammonia supply hole. 13 and a comb-shaped ammonia liquid tray 14 having one end branched into a plurality, and (c) is one ammonia supply pipe 13 having one ammonia supply hole and a rectangular ammonia liquid tray having a plurality of openings. (D) is composed of a plurality of ammonia supply pipes 13 having one ammonia supply hole and a square ammonia liquid receiving tray 14, and (e) is a single ammonia supply having a plurality of ammonia supply holes. (F) is a plurality of ammonia supply pipes 13 each having one ammonia supply hole, and corresponding to this. (G) includes a plurality of ammonia supply pipes 13 each having one ammonia supply hole, a plurality of ammonia supply pipes 13 disposed opposite thereto, and a plurality of ammonia supply pipes 13 corresponding thereto. It consists of an ammonia liquid receiver 14.

FIG. 3 shows an example of the ammonia liquid receiving tray 14. FIG. 3 (a) has a flat plate shape whose side surface is expanded in the upward direction, (b) is a circular saucer whose side surface is expanded in the upward direction, and (c) has a cylindrical shape, (D) has a flat plate shape whose side surface is reduced in diameter upward, (e) has a rectangular parallelepiped shape with a high side surface, (f) has a rectangular parallelepiped shape with a low side surface, and (g) has a side surface shape. And (h) has a cylindrical shape whose side surface is high and whose diameter is increased upward. In both cases, the upper part is an opening, and vaporized ammonia is released from here.
The present embodiment is not limited to the shape and configuration shown in FIGS. 2 and 3 and can be applied to any shape and configuration that can achieve the same purpose.

In addition, the ammonia liquid tray 14 has an area ratio that occupies a gas flow path cross section of the tray 14 within a range of 2 to 80% with respect to a gas flow path cross-sectional area in the duct 11, preferably The area ratio is in the range of 2 to 50%.
This is because if the area ratio is 2% or less, the minimum heat transfer area required for vaporization of the ammonia 30 cannot be secured, and if the area ratio is 80% or more, the catalyst layer 16 This is because an excessive pressure loss rise exceeding the pressure loss occurs, and smooth operation of the denitration apparatus 10 is hindered. Further, when the area ratio is in the range of 2 to 50%, the superficial velocity is set to an appropriate value, which is preferable.
Further, the tray 14 may have a structure in which fins are attached to the surface in contact with the lower exhaust gas 31 so that heat transfer with the exhaust gas 31 is promoted, and the surface in contact with the upper ammonia solution 30 has a fin shape. A structure may be used in which heat transfer between the exhaust gas 31 and the ammonia liquid 30 is promoted.

The exhaust gas baffle plate 15 has a structure in which an exhaust gas ventilation part is provided on a flat plate, a corrugated plate, or a curved plate, and one or a plurality thereof are laminated. Here, with reference to FIG.4 and FIG.5, the specific example of the waste gas baffle plate 15 applied to integrated filtration dust collector 10 'provided with the waste gas denitration apparatus 10 which concerns on a present Example as an example is demonstrated. To do.
As shown in FIG. 4, the exhaust gas denitration device 10 is provided above the integrated filter dust collector 10 ′, and a plurality of filter cloths 24 are provided below it. One or a plurality of baffle plates 15 provided between the ammonia supply pipe 13 and the catalyst layer 16 in the duct 11 of the exhaust gas denitration apparatus 10 are installed and have exhaust gas vents through which the exhaust gas 31 flows. . When a plurality of the baffle plates 15 are stacked, the baffle plate 15A on the exhaust gas upstream side is formed with an exhaust gas vent so that the exhaust gas 31 is mixed, and the baffle plate 15B located on the downstream side of the gas flow is The exhaust gas ventilation part is preferably formed so that the exhaust gas 31 is rectified.
These baffle plates 15A and 15B are provided with a flat plate, a corrugated plate, or a curved plate, and have a structure in which an exhaust gas passage hole is formed as the exhaust gas ventilation section, or exhaust gas in a groove shape or a slit shape. It has a ventilation part or a cross-shaped structure and has an exhaust gas ventilation part in the gap. Further, the baffle plates 15A and 15B themselves may have fine through holes. A baffle plate is preferably installed so that the ratio of the exhaust gas ventilation section is 1 to 50% in the empty tower cross section, and preferably 3 to 20%. These baffle plates 15A and 15B play a role of mixing the ammonia water 30 supplied into the exhaust gas from the ammonia supply pipe 13 so as to have a uniform concentration in the exhaust gas. As the ratio is reduced, the mixing effect increases, but the pressure loss also increases. Therefore, the pressure loss in the exhaust gas dispersion portion needs to be 50 mmAq or less, preferably 20 mmAq or less, and thus the above range is determined.

FIG. 5 shows a cross-sectional view and an arrangement example of the baffle plate 15A (or 15B). (i) is a flat plate, (ii) is a corrugated plate, (iii) is a flat plate with an inclination, (iv) is a flat plate with a square shape, and (v) is a baffle plate made of a flat plate. Sectional drawing of what laminated | stacked the 2nd step | paragraph so that the exhaust gas ventilation part of eyes may be covered is shown. In (v), the mixing effect is high and the homogenization of ammonia is promoted. Further, (a) is a structure in which rectangular exhaust gas vents 15a are formed at both ends of the baffle plate 15A (or 15B). Since the exhaust gas containing ammonia is once concentrated on the exhaust gas ventilation part 15a and then dispersed, the ammonia and the exhaust gas are sufficiently mixed, and the ammonia concentration distribution can be made uniform. Similarly, (b) is a structure in which rectangular exhaust gas vents 15b are formed at both ends and the center of the baffle plate 15A (or 15B), and (c) is a rectangular shape on the baffle plate 15A (or 15B). (D) is a slit structure in which a plurality of groove-like exhaust gas vents 15d are drilled in parallel on the baffle plate 15A (or 15B), and (e). Is a porous structure in which the baffle plate 15A (or 15B) is punched to form a plurality of minute exhaust gas vents 15e, and (f) is an exhaust gas vent 15h on the outer periphery of the baffle plate 15A (or 15B). And the baffle plate 15 is supported by a baffle plate support rod 15i. In these structures, the exhaust gas vents 15a to 15e are formed so that the exhaust gas flow has a low pressure loss. In any structure, the ammonia concentration distribution in the exhaust gas can be made uniform, and the denitration efficiency in the catalyst layer 16 at the subsequent stage can be improved.
Note that the structure of the baffle plate 15A (or 15B) is not limited to the above-described structure, and may be any structure as long as the ammonia concentration distribution in the exhaust gas is made uniform.

The shape of the catalyst used for the catalyst layer 16 may be any of a pellet shape, a honeycomb shape, a fiber shape, a sheet shape, and the like, but a pellet shape catalyst is particularly preferable. This is because in the decomposition of harmful substances with a large molecular weight such as dioxins, the membrane resistance in the vicinity of the catalyst surface can be lowered by making the catalyst into pellets, fibers, or sheets, and the decomposition performance is remarkably improved. Although it can be improved, it is a pellet catalyst that is relatively easy to manufacture and inexpensive. Moreover, it is because the exhaust gas denitration apparatus 10 can be reduced in size from the shape and it has the stirring effect of the exhaust gas which passes the catalyst layer 16. As the catalyst layer 16, for example, a vanadium oxide-based, tungsten oxide-based, molybdenum oxide-based, titanium oxide-based, or silicon oxide-based metal catalyst can be suitably used.
In the catalyst layer 16, a catalytic reaction occurs when the exhaust gas comes into contact with the catalyst in the presence of ammonia injected at the upstream side, and nitrogen oxide (NO _x ) in the exhaust gas is converted into nitrogen gas (N ₂ ). And water (H ₂ O). A plurality of the catalyst layers 16 may be stacked.

The operation of the exhaust gas denitration apparatus 10 having the above configuration will be described. The ammonia liquid 30 dropped from the ammonia supply pipe 13 is stored in the ammonia liquid tray 14, and the sensible heat of the exhaust gas 31 is generated in the tray 14. It vaporizes using it and is mixed in the exhaust gas 31 as ammonia gas. The exhaust gas 31 mixed with the ammonia gas is stirred by the baffle plate 15 and introduced into the catalyst layer 16 in a state where the ammonia gas is dispersed substantially uniformly in the exhaust gas. Then, decompose NO _x in exhaust gas to nitrogen and water by catalytic reaction in the exhaust gas 31 which passed through the catalyst layer 16 under the ammonia coexist.

As described above, in this embodiment, the ammonia supply unit 12 is configured by only the ammonia supply pipe 13 and the ammonia liquid receiving tray 14, so that the apparatus can be simplified, and the apparatus can be reduced in size and saved in space. Further, since it is not necessary to use an external heat source for vaporizing the ammonia liquid 30, the running cost can be reduced, and since water vapor or the like is not used, water vapor generated in the combustion facility can be sent to power generation. Furthermore, since there is no dripping, it is possible to avoid problems such as equipment corrosion and catalyst elution defects, and the ammonia liquid supply hole is difficult to block, so that stable denitration processing can be performed. Become. Furthermore, since the baffle plate 15 is provided, the ammonia gas and the exhaust gas 31 are sufficiently mixed, so that the denitration performance can be improved.
This embodiment is particularly effective when the residence time until reaching the catalyst after ammonia spraying is short. Further, in this embodiment, the duct cross-sectional area is small due to the gas flow in the vertical direction, and when the area necessary for vaporization cannot be secured in the ammonia liquid tray or in the gas flow in the horizontal direction, the ammonia liquid is effectively vaporized and uniform. Can be mixed.

  Further, in this embodiment, the ammonia liquid tray 14 is arranged horizontally, but as shown in FIG. 7, the ammonia liquid tray 14 is inclined so that the side away from the ammonia supply hole is downward. Anyway. As a result, the ammonia liquid dripped from the ammonia supply hole can quickly flow over the entire surface of the tray 14, the ammonia liquid can be uniformly vaporized from the entire surface of the tray, and the dispersibility of the ammonia gas in the exhaust gas can be improved. Is possible.

Here, it is considered that the ammonia tray 14 has a heat transfer area necessary for vaporizing the ammonia liquid when the following conditions are satisfied.
As described above, the ammonia liquid tray 14 has an area ratio in which the ammonia liquid tray 14 occupies the gas flow path cross section is in a range of 2 to 80% with respect to the gas flow path cross sectional area in the duct. The area ratio is preferably in the range of 2 to 50%.
As a specific example, when a flat bottom (thickness 2 mm) tray 14 as shown in FIG. 6 is assumed, the bottom surface area of the tray required to vaporize the ammonia liquid 30 is examined, and the duct cross-sectional area is determined. The result estimated about the ratio of a saucer bottom surface area is shown.
As an object to be treated, exhaust gas discharged from a waste incinerator was used. This exhaust gas has a gas amount of 50,000 Nm ³ / h, a temperature of 200 ° C., a NO _x concentration of 100 to 150 ppm, an ammonia equivalent ratio of 0.7 to 1.0, and a flow rate in the duct of 0.5 to 10 m / s.

In the examination, it is assumed that the ammonia liquid 30 existing in the tray 14 evaporates by heat transfer from the bottom of the tray and convective heat transfer from the upper liquid level in the duct where the exhaust gas flow is, and the supplied ammonia liquid 30 is The bottom surface area of the tray required for vaporization was estimated, and the ratio to the duct cross-sectional area was derived.
As a case where the ammonia liquid tray 14 is minimized, the amount of treated NO _x is small (NO _x concentration 100 ppm, assuming a NOx removal rate of about 70%, NH ₂ equivalent ratio 0.7), and the superficial velocity is as fast as 10 m / s, saucer bottom area duct cross section area to 2.4 m ² is 0.063 ^2, the area ratio of the pan becomes 2.6%. The results under other conditions in which the ammonia liquid tray 14 becomes larger are shown in Table 1 below.

In addition, the ammonia liquid pan is maximized in anticipation of a safety factor against exhaust gas drift in the duct, heat transfer failure due to dirt such as dust on the pan 14 and corrosion, and NH ₃ supply increase due to response delay in NH ₃ control. As a case, the area ratio of the saucer is 80%. This value is an appropriate value that does not cause an excessive pressure increase.
Accordingly, the ratio of the NH ₃ liquid receiver bottom surface area to the duct cross-sectional area is in the range of 2 to 80%, preferably 2 to 50%, and within this range, the ammonia receiver 14 is sufficient to vaporize the ammonia liquid. It was confirmed to have a heat transfer area.
This is assumed for a flat-bottom saucer, and this is not the case when the wall of the saucer is high and heat transfer from the side can be considered. In the case of such a saucer, the shape of the ammonia liquid saucer can be determined by considering the sum of the areas of the contact surface with the ammonia liquid as the above-mentioned saucer bottom surface area among the bottom surface and the side surface.

FIG. 8 is a schematic cross-sectional view of an integrated filter dust collector according to Embodiment 2 of the present invention. The integrated filtration dust collector 20 according to the second embodiment includes the exhaust gas denitration device 10 described in the first embodiment. The detailed description of the same configuration as that of the first embodiment is omitted.
As shown in the figure, this integrated filter dust collector 20 includes a main body 21 having a cylindrical filter cloth attached to the upper part and a lower part formed in a hopper shape, and an exhaust gas inlet 22 provided at the lower part of the main body. And an exhaust gas outlet 23 provided in the upper part of the main body, and the exhaust gas 31 passes upward from the exhaust gas inlet 22 to the exhaust gas outlet 23.
In the main body 21, a dust collecting portion in which a plurality of cylindrical filter cloths 24 are arranged, a catalyst layer 16 disposed in the vicinity of the exhaust gas outlet 23 above, a filter cloth 24 and the catalyst layer. The ammonia supply unit 12 disposed between the ammonia supply unit 12 and the baffle plate 15 disposed between the ammonia supply unit 12 and the catalyst layer 16 are accommodated.

A plurality of filter cloths 24 are suspended from the filter cloth fixing part provided at the upper part of the main body, and the dust collecting part is arranged in parallel along the gas flow. In the dust collecting part, soot dust contained in the exhaust gas 31 and chemicals such as slaked lime sprayed on the upstream side of the dust collecting device 20 adhere to and accumulate on the filter cloth surface to form a dust layer. On the other hand, the acid gas contained in the exhaust gas reaches the surface of the deposited dust layer while causing a neutralization reaction with the entrained chemicals, but the acid gas remaining when passing through here is Further neutralization reaction occurs with the unreacted chemical in the dust layer, and most of the acid gas is removed here.
The filter cloth 24 is preferably washed periodically. For washing, a backwash nozzle (not shown) is arranged above the filter cloth 24, air is sent to the backwash nozzle, high pressure air is sprayed on the filter cloth 24 using the venturi effect, and it adheres to the filter cloth. Remove the dust layer. The dust containing the fly ash that has been removed is discharged from the hopper below the main body 21.

In the integrated filtration dust collector 20 according to the present embodiment, the exhaust gas 31 introduced into the apparatus main body 21 from the exhaust gas inlet 22 first passes through the filter cloth 24 to remove dust and the like, and then supplies the ammonia. The ammonia gas is mixed with the ammonia gas supplied at the section 12 and stirred and mixed when passing through the baffle plate 15, and the ammonia gas is dispersed and introduced into the catalyst layer 16. In the catalyst layer 16, NO _x in the exhaust gas is decomposed into nitrogen and water by a catalytic reaction in the presence of ammonia.

  As described above, in the dust collector 20 according to the present embodiment, the dust collector and the denitration layer 16 are integrated to reduce the size of the device, and the exhaust gas baffle plate 15 is provided. The ammonia concentration distribution can be made uniform, so that the denitration performance can be improved, and the ammonia odor can be eliminated from the dust collected by the dust collector 20.

Comparative example

FIG. 9 shows a schematic cross-sectional view of an integrated filtration dust collector according to a comparative example of the present invention. In the integrated filter dust collector 20 ′ according to this comparative example, the detailed description of the same configuration as that of the second embodiment is omitted.
As shown in the figure, the integrated filter dust collector 20 ′ includes a main body 21 having a filter cloth 24 attached to the upper part and a lower part formed in a hopper shape, an exhaust gas inlet 22 provided in the lower part of the main body, An exhaust gas outlet 23 provided at the upper part of the main body, and the exhaust gas 31 passes upward from the exhaust gas inlet 22 to the exhaust gas outlet 23.
In the main body 21, a dust collecting portion in which a plurality of cylindrical filter cloths 24 are arranged, a catalyst layer 16 disposed in the vicinity of the exhaust gas outlet 23 above, a filter cloth 24 and the catalyst layer. The ammonia supply unit 12 disposed between the ammonia supply unit 12 and the baffle plate 15 disposed between the ammonia supply unit 12 and the catalyst layer 16 are accommodated.

Next, as a characteristic configuration of this comparative example, the configuration of the ammonia supply unit 12 will be described with reference to FIGS. 10 and 11. In this comparative example, the ammonia supply unit 12 includes a passage 17b into which the ammonia liquid 30 is supplied and a porous body 17a having a plurality of fine holes through which the ammonia liquid 30 permeates on the outer periphery of the passage 17b. It is comprised by the ammonia supply body 17 which becomes.
The ammonia supplier 17 may be cylindrical as shown in FIG. 10 (a), may be rectangular as shown in FIG. 10 (b), and the surface has irregularities. The shape is not limited. As the porous body 17a, a metal porous body, a ceramic porous body, a heat-resistant polymer porous body, or the like is preferably used.
Further, as shown in FIGS. 11A and 11B, the ammonia supplier 17 may have a two-dimensionally coupled shape on a plane, or a gas as shown in FIG. They may be combined so as to form an exhaust gas flow path in the flow direction, or may be combined three-dimensionally at random.
Further, one or a plurality of the ammonia supply bodies 17 can be arranged.

According to this comparative example, the ammonia liquid 30 supplied to the ammonia supply body 17 permeates the surface of the supply body from the porous body 17a and in the middle of permeating the contact surface with the exhaust gas 31 or micropores. It is vaporized by sensible heat and ammonia gas is mixed in the exhaust gas.
Thus, by supplying the ammonia liquid 30 as it is into the exhaust gas duct and vaporizing it uniformly from the entire surface of the ammonia supply body 17, the effect of uniformly dispersing ammonia gas is enhanced.

12 and 13 show an exhaust gas treatment facility according to Embodiment 3 of the present invention. The exhaust gas treatment facility according to the third embodiment is configured to include the integrated filtration dust collector 20 described in the second embodiment.
As shown in FIG. 12, the exhaust gas treatment facility includes an acidic gas removal agent introduction means for introducing an acidic gas removal agent 41 having deliquescence to the exhaust gas 31 discharged from the combustion facility 40, and the introduction of the acidic gas removal agent. means in the subsequent stage or at the same time, includes a hydrated lime introducing means for introducing slaked lime 42, and the integrated filtering dust collector 2 0, and a chimney 43 for the process gas 32 atmospheric discharge from the dust collecting device 20, the.

Examples of the deliquescent acidic gas removing agent 41 include sodium hydroxide (NaOH), sodium bicarbonate (NaHCO ₃ ), sodium carbonate, sodium carbonate such as (Na ₂ CO ₃ ), potassium hydroxide (KOH), A potassium-based agent such as potassium hydrogen carbonate (KHCO ₃ ) or potassium carbonate (K ₂ CO ₃ ) can be used. These chemicals are preferably used in liquid or slurry form, and a disk-like rotary atomizer or the like can be used for spraying. In addition, when spraying the liquid chemical, it may be introduced into an existing temperature-decreasing tower and sprayed, whereby the temperature reduction effect of exhaust gas can be obtained at the same time.
On the other hand, the slaked lime 42 is preferably in powder form, but may be in slurry form.
In addition, as for the introduction amount of these chemical | medical agents, it is good that the equivalent ratio of the said acidic gas removal agent 41 is 2.0 or less, and the equivalent ratio of the said slaked lime 42 is 2.0 or less.
Since the acid gas removing agent has deliquescence, if it is excessively added, the unreacted acid gas auxiliary agent becomes sticky and the filter cloth is clogged. Moreover, chemical | medical agent cost will increase when many acid gas removal agents and slaked lime are used. For this reason, the equivalence ratio is preferably 2.0 or less.
Furthermore, preferably, the equivalent ratio of the acid gas removing agent is 0.5 to 1.5, and the equivalent ratio of the slaked lime 42 is 0.1 to 1.6.
The acid gas removing agent is particularly reactive with strong alkaline substances such as sodium hydroxide (NaOH), and the introduced agent contributes to almost the entire reaction, so that the equivalent ratio of the combined effect with slaked lime is 0.00. If it is 5 or more, it is preferably 1.5 or less, which does not cause clogging of the filter cloth. In addition, slaked lime is also preferably set to an equivalent ratio of 0.1 or more that serves as a minimum filter cloth protective agent, and 1.6 or less, which can sufficiently remove the remaining acidic gas with the acidic gas removing agent.

In the exhaust gas treatment apparatus, first, the exhaust gas 31 from the combustion facility 40 is reduced in temperature to about 200 ° C. with a boiler and a temperature reducing tower (not shown), and then the acidic gas removing agent 41 is sprayed on the exhaust gas to produce HCl, SO _x. After neutralizing and removing the acidic gas such as slaked lime 42 is sprayed after or simultaneously with the acid gas removal agent 21 in the exhaust gas duct and the dust layer on the dust collecting surface of the dust collector 20. The remaining acid gas is neutralized and removed. Then, the dust collector 20 removes dust and removes organic halogen compounds such as dioxins, and in the presence of ammonia gas released from the ammonia supply unit 12, denitration and gaseous dioxins are performed in the catalyst layer 16. The processing gas 32 from which the organic halogen compound is decomposed and these harmful substances are removed is discharged from the chimney 43 to the atmosphere.

According to the present embodiment, in addition to the slaked lime 42, the combined use of the acidic gas removing agent 41 having high acid gas neutralization efficiency and excellent removal performance reduces the amount of chemicals used and reduces the amount of chemical used in the filtration dust collector 10. Since the amount of fly ash collected is also reduced, the chemical cost and the ash treatment cost are reduced.
Further, by using a highly deliquescent agent such as the acidic gas removing agent 41, water is interposed in the vicinity of the slaked lime particles, the neutralization reaction between the slaked lime and the acidic gas is promoted, and the reaction efficiency of the slaked lime 42 is increased. The removal efficiency is further increased.

Further, in the acid gas removing agent 41, since the reactive organisms and unreacted substances after spraying become very fine fine particles and have deliquescence, conventionally, the filter cloth 24 is clogged and its life is shortened. An auxiliary agent (such as diatomaceous earth) for protecting the filter cloth 24 had to be sprayed in large quantities, but in this embodiment, the slaked lime 42 contributes to the acid gas removal performance by spraying the slaked lime 42 in the subsequent stage. However, since it plays a role as a filter cloth protecting agent, the amount of the auxiliary spray for protecting the filter cloth is remarkably reduced or it becomes unnecessary to spray, so that the acid gas can be efficiently removed at low cost.
Further, by spraying the acid gas removing agent 41 in the temperature reducing tower, the neutralization reaction rate with the acid gas is further promoted without installing a new medicine supply space or supply seat and by interposing water. Costs are reduced by reducing the amount of drug used.
In this manner, the supply of the acid gas removing agent 41 and the slaked lime 42 improves the acid gas removal performance and suppresses the poisoning deterioration of the catalyst, so that it is not necessary to reheat the exhaust gas in the previous stage of the catalyst layer. Therefore, the integrated filter dust collectors 20 and 20 ′ shown in the second and third embodiments in which the catalyst layer 16 is integrated with the dust collecting unit can be suitably used, leading to a reduction in initial cost and saving reheating energy. The running cost can also be reduced.

FIG. 13 shows another example of the exhaust gas treatment apparatus shown in FIG. In the exhaust gas treatment facility, a temperature reduction tower 44 that sprays and cools the exhaust gas 31 discharged from the combustion equipment 40 and cools, and an acid gas removal agent that sprays a liquid acid gas removal agent 41 in the temperature reduction tower 44. An introduction means, a slaked lime introduction means for introducing the slaked lime 42 into the exhaust gas after the acidic gas removing agent introduction means, the integrated filtration dust collector 20, and the processing gas 32 from the dust collector 20 are released into the atmosphere. And a chimney 43.
Further, the converging a SOx concentration contained in the process gas 32 at a location downstream of the filtration apparatus 20 continuously detects, as the detected SO _x concentration was is equal to or less than a predetermined of the SO _x concentration, acid gases A control device 45 that controls at least one of the removal agent introduction amount and the slaked lime introduction amount is provided. For example, when the detected SO _x concentration is equal to or higher than a predetermined reference value, the control device 45 may control to increase the acid gas removal agent 41 or to increase the amount of slaked lime 42. Further, the ratio of the introduction amount of the acidic gas removing agent 41 and the slaked lime 42 may be controlled.
Further, the HCl concentration or the SO _x concentration and the HCl concentration contained in the processing gas 32 are continuously detected at the downstream side of the dust collector 20, and the detected HCl concentration or SO _x concentration is respectively predetermined. The concentration may be controlled to be equal to or less than the HCl concentration or the SO _x concentration.

Thus, the SO _x concentration continuously monitored at a location downstream of the dust collecting device 20, by optimizing the amount of spray agent gas removing agent and slaked lime so as to be less than a predetermined SO _x concentration levels, wasteful drug delivery And the running cost is reduced, and the poisoning deterioration of the catalyst due to SO _x can be suppressed.

FIG. 14 illustrates an exhaust gas treatment facility according to the fourth embodiment. The detailed description of the same configuration as that of the third embodiment is omitted.
As shown in the figure, this exhaust gas treatment facility includes slaked lime introducing means for introducing slaked lime 42 into the exhaust gas 31 discharged from the combustion facility 40, and an acid gas removing agent having deliquescence at the subsequent stage of the slaked lime introducing means. 41, an acid gas removing agent introducing means for introducing 41, the integrated filtration dust collector 20, and a chimney 43 for releasing the processing gas from the dust collector 20 to the atmosphere.
In the exhaust gas treatment apparatus, the exhaust gas 31 from the combustion facility 40 is first cooled to about 130 to 250 ° C., preferably about 150 to 210 ° C. with a boiler and a temperature reducing tower (not shown), and then slaked lime 42 is added to the exhaust gas. After spraying and roughing off acidic gases such as HCl and SO _x , a deliquescent acidic gas removing agent 41 is sprayed in the subsequent stage to form a dust layer in the exhaust gas duct and on the surface of the dust collector of the dust collector 20. , The acidic gas removing agent 41 is not completely removed and the remaining acidic gas is neutralized and removed.
In this way, in the treatment when the acid gas concentration is particularly high, after removing the acid gas with low-cost slaked lime, although the removal performance is low, an acid gas removing agent having high deconcentration efficiency and excellent deliquescence is obtained. By spraying a small amount and removing it to a predetermined concentration, it is possible to suppress an increase in drug cost and to remove acid gas economically and efficiently as a total. In this case as well, since unreacted slaked lime is present, it plays a role as a filter cloth protective agent.

1 is a schematic cross-sectional view of an exhaust gas denitration apparatus according to Embodiment 1 of the present invention. It is a schematic plan view which shows the example of the ammonia supply part of FIG. It is a schematic perspective view which shows the example of the ammonia liquid receiving tray of FIG. It is a perspective view of an integrated filtration dust collector provided with the exhaust gas denitration device of FIG. It is a top view which shows the example of the baffle plate which concerns on this Example 1. FIG. 2 is a diagram illustrating a specific device configuration according to the first embodiment. It is a schematic sectional drawing of the denitration apparatus which shows the other structure of Example 1 of this invention. It is a schematic sectional drawing of the integrated filtration dust collector which concerns on Example 2 of this invention. It is a schematic sectional drawing of the integrated filtration dust collector which concerns on the comparative example of this invention. It is a schematic perspective view which shows the example of the ammonia liquid supply body of FIG. It is a schematic plan view which shows the example of the ammonia supply part of FIG. It is a figure which shows the waste gas processing equipment which concerns on Example 3 of this invention. It is a figure which shows the waste gas processing equipment which comprised the chemical | medical agent introduction amount control apparatus in addition to FIG. It is a figure which shows the waste gas processing equipment which concerns on Example 4 of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Exhaust gas denitration apparatus 11 Duct 12 Ammonia supply part 13 Ammonia liquid supply pipe 14 Ammonia liquid tray 15 Baffle plate 16 Catalyst layer 17 Ammonia liquid supply body 20 and 20 'Integrated filtration dust collector 24 Filter cloth 30 Ammonia liquid 31 Exhaust gas 32 Treatment Gas 41 Acidic gas remover with deliquescence 42 Slaked lime 45 Controller

Claims (9)

In an exhaust gas denitration apparatus comprising: a catalyst unit that removes nitrogen compounds in exhaust gas; and an ammonia supply unit that is disposed in a gas flow channel upstream of the catalyst unit.
The ammonia supply unit is disposed below the ammonia liquid supply pipe and an ammonia liquid supply pipe for supplying the ammonia liquid into the gas flow path, and the ammonia liquid supplied from the ammonia liquid supply pipe is exposed to the exhaust gas. Ammonia liquid vaporizing section, which is composed of a saucer formed so as to be vaporized by heat, and extends and arranged in the transverse cross-sectional direction perpendicular to the gas flow,
An exhaust gas dispersion part for dispersing ammonia gas vaporized from the ammonia liquid vaporization part in the exhaust gas;
The ammonia vaporization part and the exhaust gas dispersion part are arranged in the apparatus main body along the flow direction of the gas flow from the bottom to the top,
An exhaust gas denitration apparatus, wherein a tray that forms the ammonia liquid vaporizing portion is disposed so as to extend in a transverse cross-sectional direction in the tank perpendicular to the gas flow. The exhaust gas denitration apparatus according to claim 1, wherein the nitrogen compound contained in the exhaust gas discharged from the waste incinerator, gasification furnace or melting furnace is removed together with dioxin.
An exhaust gas denitration apparatus, wherein the catalyst used in the catalyst section is in the form of pellets. The exhaust gas dispersion part is a structure in which baffle plates having an exhaust gas ventilation part are stacked in a plurality of stages at intervals along the flow direction of the gas flow from the bottom to the top,
The first baffle plate located on the lower side of the gas flow upstream is formed with the exhaust gas vent so that the exhaust gas is mixed, and the second baffle plate located on the gas flow downstream side above the first baffle plate, The exhaust gas denitration apparatus according to claim 1, wherein an exhaust gas ventilation part is formed so as to cover the exhaust gas ventilation part of the first baffle so that the exhaust gas is rectified. The saucer, the exhaust gas denitration apparatus according to claim 1, wherein the side away from the ammonia liquid supply hole of the ammonia solution supply pipe is inclined downward, characterized in that it is arranged. 5. The exhaust gas denitration apparatus according to claim 4 , wherein the ammonia liquid vaporizing section is a dish-shaped receiving tray, wherein an area ratio of the gas passage cross section of the ammonia liquid receiving tray is 2 to 80 with respect to a sectional area of the gas passage. % Exhaust gas denitration equipment characterized by being in the range of%. An integrated filtration dust collector comprising the exhaust gas denitration device according to any one of claims 1 to 5 in an apparatus body,
In the apparatus main body, a dust collecting part is provided below the ammonia liquid vaporizing part, in which a filtering material for removing harmful substances including nitrogen compounds, dust, and organic halogen compounds in exhaust gas is disposed. Integrated filter dust collector. An exhaust gas treatment facility comprising the integrated filter dust collector according to claim 6,
An acidic gas removing agent introducing means for introducing a deliquescent acidic gas removing agent into the exhaust gas and a slaked lime introducing means for introducing slaked lime into the exhaust gas are provided on the upstream side of the integrated filtration dust collector in the exhaust gas flow direction. ,
An exhaust gas treatment facility, wherein the slaked lime is introduced as a powder or a slurry.   The acid gas removing agent introduction means is attached to a temperature reducing tower disposed upstream of the integrated filtration dust collector in the exhaust gas flow direction, and the liquid acid gas removing agent and water are supplied to the exhaust gas in the temperature reducing tower. The exhaust gas treatment facility according to claim 7, wherein the exhaust gas treatment facility is sprayed on the exhaust gas.   Detection means for continuously detecting at least one of SOx concentration or HCl concentration in the exhaust gas is provided on the downstream side in the exhaust gas flow direction of the integrated filtration dust collector, and the SOx concentration or HCl concentration detected by the detection means is provided. 9. The exhaust gas treatment facility according to claim 8, wherein at least one of the acidic gas removing agent and the slaked lime is introduced based on at least one of the above.

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