JP4015496B2 - Exhaust gas treatment equipment - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an exhaust gas treatment apparatus included in an incineration system for, for example, municipal waste or incineration sludge.
[0002]
[Prior art]
FIG. 5 is a schematic diagram of an exhaust gas treatment device included in an incineration system in the prior art. As shown in FIG. 5, municipal waste or sewage sludge is incinerated in an incinerator 110 (not shown) of the incineration system. The exhaust gas generated thereby passes through the boiler 111 or the like (not shown) and then is supplied to the temperature reducing tower 120 through the duct 180. Since the temperature reducing tower 120 is connected to the water source 122, the exhaust gas is cooled to, for example, 150 ° C. by the water supplied into the temperature reducing tower 120 by the pump 121. Next, the exhaust gas passes through the bag filter 130 from the temperature reducing tower 120 through the duct 181, and dust and the like are collected in the bag filter 130 and then discharged from the chimney (not shown) through the duct 182.
[0003]
Since the exhaust gas generated in the incinerator 110 contains acid gases such as SOx and HCl, it is necessary to discharge the exhaust gas after neutralizing the acid gas in the exhaust gas. In the prior art as shown in FIG. 5, a slaked lime nozzle 160 is provided in the exhaust gas treatment apparatus 100. The slaked lime nozzle 160 is connected to a slaked lime feeder 155 installed in the slaked lime silo 150. When the exhaust gas treatment apparatus 100 is used, the slaked lime in the slaked lime silo 150 is supplied from the slaked lime nozzle 160 to the duct 181 by the blower 156, thereby neutralizing the acidic gas in the duct 181. Since the neutralization reaction of acid gas by slaked lime is effectively performed when water is present, the slaked lime nozzle 160 is installed between the temperature reducing tower 120 and the bag filter 130. That is, the slaked lime is supplied to the exhaust gas after water is supplied in the temperature reducing tower 120.
[0004]
[Problems to be solved by the invention]
However, the temperature of the exhaust gas entering the bag filter 130 is relatively high, for example, 150 ° C. Therefore, there is a possibility that the water supplied in the temperature reducing tower 120 has already evaporated when passing through the slaked lime nozzle 160. In such a case, slaked lime and liquid water do not coexist, and the neutralizing action of the acid gas in the exhaust gas is reduced.
[0005]
FIG. 6 is a schematic diagram of an exhaust gas treatment apparatus included in another incineration system, for example, an incineration system as disclosed in JP-A-8-131775. This exhaust gas treatment apparatus 101 supplies a high-viscosity slaked lime slurry formed by previously mixing water and slaked lime to the reaction evaporation tower 121 in order to allow the liquid water and slaked lime to coexist before being evaporated. . In this case, since the atmosphere in which slaked lime and liquid water coexist is formed in advance, the acid gas can be neutralized more efficiently than the prior art exhaust gas treatment apparatus shown in FIG.
[0006]
However, in this case, a slurry tank 190 having a stirring function is separately required to form the slaked lime slurry, and a relatively powerful pump is used to supply the high-viscosity slaked lime slurry into the reaction evaporation tower 121. The initial cost increases because it is required. Moreover, since a stirring action is required to form slaked lime slurry, the running cost will also increase. Furthermore, since the slaked lime slurry has a high viscosity, the slaked lime slurry may adhere to the inner wall of the slaked lime slurry supply duct 191 and the nozzle 129 may be clogged by the slaked lime slurry. In such a case, in order to remove slaked lime slurry adhering or clogged, it is necessary to stop the exhaust gas treatment apparatus 101 in order to prevent the outflow of acid gas, and the slaked lime slurry removal operation itself is relatively complicated. is there.
[0007]
This invention is made | formed in view of such a situation, and provides the low-cost waste gas processing apparatus which can remove an acidic gas easily by forming the atmosphere where slaked lime and the water of a liquid state coexist. Objective.
[0008]
[Means for Solving the Problems]
In order to achieve the above-described object, according to the first aspect of the present invention, there is provided an exhaust gas duct through which exhaust gas flows, a temperature reducing tower provided in the exhaust gas duct through which the exhaust gas passes, and a water source. the flue gas duct in the lower stream of the reduced cooling tower and water nozzles installed in the reduced temperature within the column, the flow of the exhaust gas for supplying slaked lime from hydrated lime source to supply water There is provided an exhaust gas treatment apparatus comprising: a slaked lime nozzle installed on the exhaust gas; and a water sprayer installed in the exhaust gas duct further downstream of the slaked lime nozzle.
[0013]
That is, according to the first aspect of the present invention, since water is sprayed downstream of the slaked lime supply position, an atmosphere in which slaked lime and liquid water coexist can be formed, and therefore acid gas is easily removed. A possible exhaust gas treatment apparatus can be provided. In the case of the invention described in claim 1 , since the exhaust gas treatment device can be formed without changing the position of the nozzle for slaked lime, the manufacturing cost can be reduced and the slaked lime slurry is not used because the slaked lime slurry is not used. The possibility of clogging based on use can be eliminated.
[0014]
In addition, according to the invention described in claim 1, the inner diameter of the portion of the exhaust gas duct where the water sprayer is installed is larger than the inner diameter of the other portion, and the tip of the water sprayer is an inner diameter of a large part amount than the inner diameter of the other portions, and to be substantially flush against an inner wall of said another portion of the flue gas duct.
That is, according to the first aspect of the present invention, an atmosphere in which slaked lime and liquid water coexist is formed over a relatively wide range, whereby the acid gas can be more easily neutralized, and the Of slaked lime is prevented from adhering to the water sprayer.
[0015]
According to invention of Claim 2 , the said water sprayer is an ultrasonic water sprayer.
That is, according to the second aspect of the invention, uniform water particles having a small diameter can be sprayed, so that the acidic gas can be neutralized more easily.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the accompanying drawings. In the following drawings, the same members are denoted by the same reference numerals. In order to facilitate understanding, the scales of these drawings are appropriately changed.
FIG. 1 is a schematic diagram of an exhaust gas treatment apparatus according to a first embodiment of the present invention. As shown in FIG. 1, an exhaust gas treatment device 10 included in an incineration system (not shown) includes a temperature reducing tower 20 for reducing the temperature of exhaust gas by water cooling. A duct 80 is connected to the temperature reducing tower 20, and an acid gas, for example, a gas containing HCl or SOx flows through the duct 80. The temperature reducing tower 20 is connected by a duct 80 to, for example, a boiler (not shown) adjacent to an incinerator (not shown) of the incineration system. Therefore, exhaust gas generated in, for example, an incinerator flows in the duct 80. The bag filter 30 is disposed via the duct 81 downstream of the temperature reducing tower 20 with respect to the flow of exhaust gas in the duct 80. Further, a chimney (not shown) is disposed downstream of the bag filter 30 via a duct 82.
[0017]
As described above, the exhaust gas generated in the incinerator (not shown) passes through the boiler, and then is supplied to the lower part of the temperature reducing tower 20 through the duct 80. Next, the exhaust gas is cooled while rising in the temperature reducing tower 20, and enters the bag filter 30 from the upper part of the temperature reducing tower 20 through the duct 81. The dust in the exhaust gas is collected by the bag filter 30 and then discharged from the chimney (not shown) through the duct 82.
[0018]
As shown in FIG. 1, a water nozzle 28 connected to the water source 22 and the compressor 25 is provided in the temperature reducing tower 20. When the exhaust gas treatment apparatus 10 is used, the water in the water source 22 is supplied into the temperature reducing tower 20 through the control valve 23 and the water nozzle 28 by the pump 21. Similarly, air is supplied into the temperature reducing tower 20 through the control valve and the water nozzle 28 by the compressor 25. As a result, the temperature of the exhaust gas passing through the temperature reducing tower 20 is reduced to about 150 ° C. In FIG. 1, a two-fluid nozzle using water and air is used, but a one-fluid nozzle using only water may be used. The use of a rotating disk type nozzle is also included in the scope of the present invention.
[0019]
The exhaust gas treatment apparatus 10 according to the present invention includes a slaked lime silo 50, and slaked lime (Ca (OH) ₂ ) is introduced into the slaked lime silo 50. As shown in FIG. 1, a slaked lime feeder 55 is disposed below the slaked lime silo 50. Slaked lime is supplied into the exhaust gas treatment apparatus 10 by a blower 56. Thereby, the acidic gas contained in the exhaust gas flowing through the exhaust gas treatment device 10, such as HCl and SOx, can be neutralized.
[0020]
In the first embodiment of the present invention, the slaked lime nozzle 60 for supplying slaked lime to the exhaust gas treatment device 10 is installed in a duct 80 located upstream of the temperature reducing tower 20 with respect to the flow of exhaust gas. . When the exhaust gas treatment apparatus 10 is used, slaked lime is supplied from the slaked lime nozzle 60 into the duct 80 by the blower 56. Therefore, the exhaust gas flowing through the duct 80 contains slaked lime. Next, the exhaust gas enters the temperature reducing tower 20 from the duct 80. In the temperature reducing tower 20, the water from the water nozzle 28 is supplied to the exhaust gas containing slaked lime. That is, in the first embodiment of the present invention, since water is supplied to the exhaust gas that contains slaked lime, an atmosphere in which slaked lime and liquid water coexist can be formed. Since the neutralization reaction of acidic gas by slaked lime is effectively performed when liquid water is present, the acidic gas in the exhaust gas can be easily neutralized by the first embodiment of the present invention. Become. That is, according to the present embodiment, it is possible to obtain an acid gas removing effect equivalent to that when slaked lime slurry is supplied. The acid gas in the exhaust gas is neutralized in the temperature reducing tower 20 and the duct 81. Next, the exhaust gas cooled in the temperature reducing tower 20 enters the bag filter 30 through the duct 81. The temperature of the exhaust gas flowing out of the temperature reducing tower 20 is higher than the acid dew point of the acidic gas (HCl, SOx) in the exhaust gas, for example, 150 ° C. After dust and excess slaked lime in the exhaust gas are collected in the bag filter 30, the exhaust gas is discharged from a chimney (not shown) through the duct 82 later. Furthermore, since the exhaust gas treatment apparatus 10 of the present embodiment can be formed by simply changing the position of the slaked lime nozzle 160 of the prior art exhaust gas treatment apparatus 100 as shown in FIG. 5, the manufacturing cost can be reduced.
[0021]
In the present embodiment, the size of the temperature reducing tower 20 is preferably larger than that of the above-described prior art temperature reducing tower 120, thereby preventing slaked lime from adhering to the inner wall of the temperature reducing tower 20. Further, in order to prevent clogging of the water nozzle 28, it is preferable to increase the capacity of a purge fan (not shown) installed below the water nozzle 28 and the compressor 25 and the pump 21. Further, in order to prevent slaked lime from adhering to the inside of the duct 80, the slaked lime nozzle 60 is preferably installed adjacent to the temperature reducing tower 20 upstream of the temperature reducing tower 20.
[0022]
FIG. 2 is a schematic view of an exhaust gas treatment apparatus according to the second embodiment of the present invention. As shown in FIG. 2, the slaked lime nozzle 60 in this embodiment is installed downstream of the water flow at the outlet 29 of the water nozzle 28. In particular, the slaked lime nozzle is preferably installed adjacent to the air outlet 29 downstream of the water nozzle 28. In the present embodiment, slaked lime is supplied from the slaked lime nozzle 60 before the water from the water nozzle 28 evaporates in the temperature reducing tower 20. Therefore, also in this embodiment, an atmosphere in which slaked lime and liquid water coexist can be formed. As described above, the neutralization reaction of the acid gas by slaked lime is effectively performed when liquid water is present, so that the acid gas in the exhaust gas can be easily neutralized by the second embodiment of the present invention. Will be able to. That is, according to the present embodiment, it is possible to obtain an acid gas removing effect equivalent to that when slaked lime slurry is supplied. Furthermore, since the exhaust gas treatment apparatus 10 of the present embodiment can be formed by simply changing the position of the slaked lime nozzle 160 of the prior art exhaust gas treatment apparatus 100 as shown in FIG. 5, the manufacturing cost can be reduced. Further, in the present embodiment, the size of the temperature reducing tower 20 is preferably larger than that of the above-described prior art temperature reducing tower 120, thereby preventing slaked lime from adhering to the inner wall of the temperature reducing tower 20. .
[0023]
FIG. 3 is a schematic view of an exhaust gas treatment apparatus according to the third embodiment of the present invention. In this embodiment, the position of the slaked lime nozzle 60 is substantially equal to the position of the conventional slaked lime nozzle 160 shown in FIG. 5, and a sprayer 90 for spraying water is provided downstream of the slaked lime nozzle 60. . As shown in FIG. 3, the sprayer 90 is connected to the water source 22 described above via a control valve 93 and a pump 27.
[0024]
In the present embodiment, since slaked lime is supplied into the exhaust gas of the duct 81 by the slaked lime nozzle 60 and then water is sprayed by the sprayer 90, an atmosphere in which slaked lime and liquid water coexist can be formed. . As described above, the neutralization reaction of acidic gas by slaked lime is effectively performed when liquid water is present, so that the acidic gas in the exhaust gas can be easily neutralized by the third embodiment of the present invention. Will be able to. Furthermore, in this embodiment, since the exhaust gas treatment device can be formed by simply installing the water sprayer without changing the position of the slaked lime nozzle, the manufacturing cost can be reduced.
[0025]
FIG. 4 is a partially enlarged view showing the vicinity of the nebulizer of the exhaust gas treatment apparatus based on the third embodiment of the present invention. In FIG. 4, the flow of the exhaust gas is indicated by arrows. As shown in FIG. 4, a buffer 85 formed by enlarging a part of the duct 81 in the radial direction is provided in the duct 81. A pair of sprayers 90 are installed to face the buffer 85 of the duct 81, and these sprayers 90 are connected to the water source 22 as described above. In such a case, the presence of the buffer 85 makes it possible to form an atmosphere in which slaked lime and liquid water coexist over a relatively wide range, so that the acidic gas can be neutralized more easily.
[0026]
In particular, as shown in FIG. 4, it is preferable that the tip of the sprayer 90 is substantially flush with the inner wall of the duct 81, thereby preventing slaked lime from the slaked lime nozzle 60 from adhering to the sprayer 90. In addition, an atmosphere in which slaked lime and liquid water coexist can be formed in a wider range. The atomizer 90 shown in FIGS. 3 and 4 is preferably an ultrasonic atomizer, which can spray uniform water particles with a small diameter, so that the acidic gas can be more easily neutralized. Further, it is preferable to supply purge air around the sprayer, and in this case, it is possible to further prevent slaked lime or the like from adhering to the sprayer.
[0027]
Further, as shown in FIG. 3, in this embodiment, it is preferable to install a thermometer 91 for measuring the temperature of the exhaust gas entering the bag filter 30. In this embodiment, after the exhaust gas temperature is lowered by supplying water in the temperature reducing tower 20, water is further supplied by the sprayer 90. Accordingly, the bag filter 30 inlet temperature is prevented from being lowered by adjusting the amount of water supplied from the water nozzle 28 by the control valve 23 in accordance with the bag filter 30 inlet temperature measured by the thermometer 91. Can do.
[0028]
Further, as shown in FIG. 3, in the present embodiment, it is preferable to provide an HCl concentration meter 92 for measuring the concentration of acid gas, for example, HCl, in the exhaust gas flowing out from the bag filter 30. In this case, the amount of slaked lime supplied from the slaked lime nozzle 60 and the amount of water supplied from the sprayer 90 can be adjusted according to the HCl concentration at the bag filter 30 outlet.
[0029]
Of course, any combination of some of these embodiments is within the scope of the present invention. Furthermore, you may make it supply a special reaction agent (special reaction adjuvant) and activated carbon with slaked lime. It is obvious that the exhaust gas treatment apparatus of the present invention can be applied to exhaust gas other than exhaust gas from an ash melting furnace or exhaust gas from an incinerator.
[0030]
【The invention's effect】
According to the invention described in each claim, a common effect is that it is possible to provide a low-cost exhaust gas treatment apparatus that can easily remove acid gas by forming an atmosphere in which slaked lime and liquid water coexist. Can be played.
[0031]
Further, attaching atmosphere and water consumption lime and liquid state coexist by forming over a relatively wide range, Rutotomoni can be more easily neutralize acidic gases, the slaked lime water sprayer from slaked lime nozzle It can provide an advantage that Ru is prevented from.
In addition , according to the invention described in claim 2 , since uniform water particles having a small diameter can be sprayed, the effect of neutralizing the acidic gas more easily can be achieved.
[Brief description of the drawings]
FIG. 1 is a schematic view of an exhaust gas treatment apparatus according to a first embodiment of the present invention.
FIG. 2 is a schematic view of an exhaust gas treatment apparatus according to a second embodiment of the present invention.
FIG. 3 is a schematic view of an exhaust gas treatment device according to a third embodiment of the present invention.
FIG. 4 is a partially enlarged view showing the vicinity of a nebulizer of an exhaust gas treatment apparatus according to a third embodiment of the present invention.
FIG. 5 is a schematic view of an exhaust gas treatment device included in an incineration system as shown in the prior art.
FIG. 6 is a schematic view of an exhaust gas treatment device included in an incineration system as shown in another prior art.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 ... Exhaust gas treatment apparatus 20 ... Temperature reduction tower 21 ... Pump 22 ... Water source 23 ... Control valve 25 ... Compressor 27 ... Pump 28 ... Water nozzle 29 ... Outlet 30 ... Bag filter 50 ... Slaked lime silo 55 ... Slaked lime feeder 56 ... Blow 60 ... Slaked lime nozzle 80 ... Duct 81 ... Duct 82 ... Duct 85 ... Buffer 90 ... Sprayer 91 ... Thermometer 92 ... Densitometer 93 ... Control valve

Claims (2)

An exhaust gas duct through which exhaust gas flows;
A temperature reducing tower provided in the exhaust gas duct and through which the exhaust gas passes;
A water nozzle installed in the cooling tower to supply water from a water source;
A slaked lime nozzle installed in the exhaust gas duct downstream of the temperature reducing tower with respect to the exhaust gas flow to supply slaked lime from a slaked lime source;
A water sprayer installed in the exhaust gas duct further downstream of the slaked lime nozzle,
The inner diameter of the water portion of the sprayer is installed in the exhaust duct is larger than the inner diameter of the other portions, and the tip of the water sprayer, a large part amount than the inner diameter of the inner diameter on the other element, the exhaust gas An exhaust gas treatment apparatus configured to be substantially flush with the inner wall of the other portion of the duct.   The exhaust gas treatment apparatus according to claim 1, wherein the water sprayer is an ultrasonic water sprayer.

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