KR20170125968A - Heavy metal removal support device for electric dust collector - Google Patents

Heavy metal removal support device for electric dust collector Download PDF

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KR20170125968A
KR20170125968A KR1020177029313A KR20177029313A KR20170125968A KR 20170125968 A KR20170125968 A KR 20170125968A KR 1020177029313 A KR1020177029313 A KR 1020177029313A KR 20177029313 A KR20177029313 A KR 20177029313A KR 20170125968 A KR20170125968 A KR 20170125968A
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heavy metal
exhaust gas
reagent
electrostatic precipitator
dust collecting
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KR1020177029313A
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Korean (ko)
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츠토무 세키카와
다케하루 아베
마사히로 오가사와라
하루오 시바야마
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스미토모 킨조쿠 코잔 엔지니어링 가부시키가이샤
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
    • B01D53/34—Chemical or biological purification of waste gases
    • B01D53/46—Removing components of defined structure
    • B01D53/64—Heavy metals or compounds thereof, e.g. mercury
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
    • B01D53/34—Chemical or biological purification of waste gases
    • B01D53/74—General processes for purification of waste gases; Apparatus or devices specially adapted therefor
    • B01D53/77—Liquid phase processes
    • B01D53/79—Injecting reactants
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B03—SEPARATION OF SOLID MATERIALS USING LIQUIDS OR USING PNEUMATIC TABLES OR JIGS; MAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
    • B03C—MAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
    • B03C3/00—Separating dispersed particles from gases or vapour, e.g. air, by electrostatic effect
    • B03C3/01—Pretreatment of the gases prior to electrostatic precipitation
    • B03C3/013—Conditioning by chemical additives, e.g. with SO3
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B03—SEPARATION OF SOLID MATERIALS USING LIQUIDS OR USING PNEUMATIC TABLES OR JIGS; MAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
    • B03C—MAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
    • B03C3/00—Separating dispersed particles from gases or vapour, e.g. air, by electrostatic effect
    • B03C3/02—Plant or installations having external electricity supply
    • B03C3/16—Plant or installations having external electricity supply wet type

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • General Chemical & Material Sciences (AREA)
  • Environmental & Geological Engineering (AREA)
  • Health & Medical Sciences (AREA)
  • Biomedical Technology (AREA)
  • Analytical Chemistry (AREA)
  • Oil, Petroleum & Natural Gas (AREA)
  • Treating Waste Gases (AREA)
  • Electrostatic Separation (AREA)
  • Gas Separation By Absorption (AREA)

Abstract

An object of the present invention is to realize heavy metal removal using a wet electrostatic precipitator.
The wet electrostatic precipitator (14) is a wet electrostatic precipitator (14), which is composed of a discharge electrode to which a high DC voltage is applied and a secondary corona discharge generated between the discharge electrode based on a DC high voltage, And a dust collecting electrode for collecting dust. The heavy metal removal supporting apparatus 13 is provided at the front end of the wet electrostatic precipitator 14 and supplies a reagent having a property of changing the heavy metal containing mercury to a form of increasing the dust collection rate compared with that before spraying, A spray nozzle 23 is provided as a spray part for spraying the spray nozzle.

Description

Heavy metal removal support device for electric dust collector

The present invention relates to a heavy metal removal supporting apparatus for an electric dust collector.

In Japan, the Minamata Treaty was adopted in October 2013 to strengthen regulations on mercury emissions. As a result, in various fields, there is a possibility that mercury emission reduction to the atmosphere by BAT (best available technology) may be imposed in the future.

For example, in the field of nonferrous smelting, there is a possibility that mercury emission reduction is imposed.

Even in the present situation, there is an example of the installation of a refining tower or an adsorption tower for discharging mercury at the front end of a sulfuric acid production line facility. However, large-scale investment and installation space are required for the installation of the purification tower and the adsorption column.

In addition, there is a possibility that mercury emission reduction to the stack may be imposed, for example, in fields other than non-ferrous smelting, such as coal firing power, industrial waste incineration, and steel-related facilities.

Conventionally, wet electrostatic precipitators (for example, see Patent Documents 1 to 3) are often provided in the field where such mercury emission reduction may be imposed.

The wet electrostatic precipitator is used for collecting harmful dust or mist from the waste gas generated in the waste incineration process as well as the sulfuric acid mist treatment or the aluminum refining exhaust gas treatment in the mining industry. As described above, the wet electrostatic precipitator is widely used as a useful device in terms of prevention of air pollution and environmental preservation.

Patent Document 1: Japanese Patent Application Laid-Open No. 2007-196159 Patent Document 2: Japanese Patent Application Laid-Open No. 2002-119889 Patent Document 3: Japanese Patent Publication No. 6-91965

For this reason, when the wet electrostatic precipitator can realize the mercury removal, it is not necessary to make a large-scale investment and installation space only for mercury removal.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object of the present invention is to realize mercury removal using a wet electrostatic precipitator.

According to an aspect of the present invention, there is provided a heavy metal removal supporting apparatus for an electric dust collector,

A discharge electrode to which a DC high voltage is applied,

And a dust collecting electrode for collecting mercury-containing heavy metal contained in the exhaust gas discharged from the discharge gas generating source by a negative corona discharge generated between the discharge electrodes based on the direct current high voltage.

And removing the heavy metal from the heavy metal,

Wherein the electric dust collecting apparatus further comprises:

And a spraying portion for spraying the reagent having the property of changing the heavy metal containing mercury to a form in which the dusting rate in the dust collecting electrode is increased as compared with that before spraying.

In addition,

It is possible to spray a reagent having a property of changing volatile harmful chloride, gaseous harmful substances, rare metals and noble metals into a form in which the dust collection rate in the dust collecting electrode is increased.

In addition,

A reagent having a property of changing the zero-valued gaseous mercury into bivalent mercury can be sprayed onto the exhaust gas.

Here, when SO 2 is contained in the exhaust gas, the reagent may be Na 2 S, NaClO, or H 2 O 2 .

In addition, the reagent may be a sulfide which forms a stable complex.

According to the present invention, mercury removal using a wet electrostatic precipitator can be realized.

1 is a view showing a configuration example of a dust collecting system according to an embodiment of the present invention.
2 is a perspective view showing a schematic structure of an outer appearance of a coupling conduit to which four spray nozzles are attached, out of the heavy metal removal supporting apparatuses in the dust collecting system according to the embodiment of the present invention.
3 is a cross-sectional view showing a schematic configuration of a wet electrostatic precipitator in a dust collecting system according to an embodiment of the present invention.
Fig. 4 is a perspective view showing a schematic structure of the inside of the housing of the wet type electrostatic precipitator of Fig. 3;

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[Configuration of dust collection system]

1 is a view showing a configuration example of an embodiment of a dust collection system to which the present invention is applied.

The dust collecting system 1 shown in Fig. 1 is provided in, for example, a non-ferrous smelter sulfuric acid factory and includes a wet electrostatic precipitator 11 as a sulfuric acid MC, an exhaust gas introducing duct 12, Respectively.

In the example of Fig. 1, the exhaust gas is a smelting exhaust gas containing sulfur dioxide which is discharged by non-ferrous smelting and passed through a cleaning tower (not shown).

The exhaust gas introduced into the exhaust gas introducing duct 12 contains mercury (hereinafter referred to as " Hg "). More specifically, the Hg contained in the exhaust gas is a gas phase Hg (hereinafter referred to as " Hg (0) ") having a valence of zero and a particulate Hg Quot;). Here, the particulate phase is a phase including both solid phase and liquid phase.

Hg (2+) is removed at an efficiency of about 98 to 99% in the wet electrostatic precipitator 11 described later. On the other hand, Hg (0) can hardly be removed by the wet electrostatic precipitator 11 described later.

Therefore, in the dust collecting system 1 of the present embodiment, the heavy metal removal supporting apparatus 13 is connected to the wet electrostatic precipitator 11 in order to change Hg (0) contained in the exhaust gas to Hg (2+) Respectively.

The heavy metal removal supporting apparatus 13 includes a reagent reservoir 21, a pump 22, and a spray nozzle 23.

The reagent reservoir 21 stores a reagent having a property of changing Hg (0) contained in the exhaust gas to Hg (2+).

That is, as a method for changing Hg (0) to Hg (2+), there are a first method using an oxidizing agent and a second method using a commonly used reducing agent to immobilize Hg.

When the first method is employed, an oxidizing agent is employed as a reagent. In this case, when SO 2 is contained in the exhaust gas as in the present embodiment, a general oxidizing agent such as KMnO 4 is unsuitable as a reagent for oxidizing SO 2 . That is, when SO 2 is contained in the exhaust gas as in the present embodiment, it is preferable to employ an oxidizing agent for selectively oxidizing Hg as a reagent.

On the other hand, when the second method is employed, a reducing agent is employed as a reagent. For example, when NaSH (sodium hydrosulfide) is employed as a reagent, Hg is fixed as a sulfide, whereby Hg (0) changes to Hg (2+).

Further details of the reagents will be described later.

The reagent stored in the reagent reservoir 21 is injected into the exhaust gas introducing duct 12 by the spray nozzle 23 through the pump 22.

2 is a perspective view showing a schematic configuration of the appearance of the exhaust gas introducing duct 12 to which the four spray nozzles 23 are attached.

In the present embodiment, as shown in Fig. 2, four spray nozzles 23-1 to 23-4 are attached at regular intervals in the inner periphery of the exhaust gas introducing duct 12. As a result, since the reagent is sprayed to every corner of the exhaust gas flowing through the exhaust gas introducing duct 12, Hg (0) can be efficiently changed to Hg (2+).

1, when the Hg (0) contained in the exhaust gas is changed to Hg (2+) in the heavy metal removal supporting apparatus 13 in this way, the exhaust gas is supplied to the wet electrostatic precipitator 11 .

That is, the exhaust gas introduced into the wet electrostatic precipitator 11 contains almost only Hg (2+). As a result, the wet electrostatic precipitator 11 can efficiently remove Hg from the exhaust gas.

[Configuration of wet electrostatic precipitator]

Next, the configuration of the wet electrostatic precipitator 11 will be described with reference to Fig.

3 is a cross-sectional view showing a schematic configuration of the wet electrostatic precipitator 11.

3 (a) and 3 (b) are cross-sectional views showing the schematic structure of the external appearance of the wet type electrostatic precipitator 11, and are cross-sectional views viewed from directions substantially perpendicular to each other.

The wet electrostatic precipitator 11 is provided with an upper casing 111, a dust collecting pole 122 serving also as a side casing, a lower casing 113, and furniture (frame 114).

The housing of the wet electrostatic precipitator 11 is constituted by combining the upper casing 111, the dust collecting pole 122 and the lower casing 113 in this order from above. The housing of the wet electrostatic precipitator 11 is fixed to the furniture 114 by a predetermined distance away from the ground. As the material of the housing of the wet electrostatic precipitator 11, conductive FRP (Fiber Reinforced Plastics) is employed in the present embodiment.

4 is a perspective view showing a schematic structure inside the housing of the wet electrostatic precipitator 11;

4, an upper grid 121, the above-described dust collecting pole 122, a lower grid 123, an electrode rod 124, and a room (not shown) are housed in the housing of the wet electrostatic precipitator 11, An electric wire 125, a weight 126, an upward spray nozzle 127, and a cleaning pipe 128 are provided.

As shown in Fig. 4, the upper grid 121, the dust collecting pole 122, and the lower grid 123 are arranged so as to be substantially parallel to each other in the horizontal direction, .

As shown in Fig. 4, the dust collecting electrode 122 is formed by arranging a plurality of "yarns" repeatedly and continuously by using a square unit as a unit (hereinafter, this unit is called "a room") .

More specifically, one direction in the substantially horizontal direction is referred to as " longitudinal direction ", and a direction perpendicular to the longitudinal direction is referred to as " lateral direction ". In this case, the dust collecting electrode 122 is formed by repeatedly arranging the N units in the longitudinal direction and arranging the M units in the transverse direction repeatedly and continuously (hereinafter referred to as "N × M").

Here, N and M are independent arbitrary integer values. In this embodiment, as shown in Fig. 4, the number of "yarns" of the dust collecting electrode 122 is N × M = 9 × 9.

In addition, the yarn of the present embodiment is a square bar made of sides having a length of 30 to 50 cm.

In addition, as the material of the dust collecting electrode 122, a conductive FRP is employed in the present embodiment.

The discharge electrode for this dust collecting electrode 122 is constituted by the electrode rod 124 and the discharge wire 125 in the present embodiment.

4, the electrode rod 124 is disposed so as to pass through the center of a predetermined " room " of the dust collecting electrode 122 in a substantially vertical direction, has an upper end fixed to the upper grid 121, Is fixed to the lower grid 123.

As shown in Fig. 4, the discharge wire 125 is suspended from the upper grid 121, and is disposed so as to pass through the center of the predetermined "yarn" of the dust collecting electrode 122 in a substantially vertical direction. The discharge wire 125 is also connected to a weight 126 provided on the upper portion of the lower grid 123 so as to have a tensile force not to be loosened.

To the electrode rod 124, a DC high voltage (charge voltage) of a negative electrode supplied from a power supply device (not shown) is directly applied. On the other hand, a DC high voltage of the negative electrode is applied to the discharge wire 125 through the upper grid 121.

The upward spray nozzles 127 are arranged above the four corners of the respective chambers of the dust collecting poles 122 so that the washing water circulating in the washing pipe 128 can flow as a fine mist . As a result, it becomes possible to clean and remove fine particles such as mist and dust attached to the dust collecting electrode 122.

In the wet electrostatic precipitator 11 of the present embodiment, the washing water is sprayed from the upward spray nozzle 127 in a substantially vertical upward direction as a fine mist. Thus, since the washing water is well dispersed, the quantity of the washing water used can be made smaller than the quantity of washing water used conventionally.

The upward spray nozzle 127 is a component contributing to the rise of the direct current high voltage of the negative electrode applied to the electrode rod 124 and the discharge wire 125.

[Operation of wet electrostatic precipitator]

As described above, a high voltage is charged between the discharge electrode (the electrode rod 124 and the discharge wire 125) and the grounded dust collecting electrode 122.

As a result, a strong current electric field is formed between the discharge electrode and the dust collecting electrode 122, and a corona discharge is vigorously generated from the discharge electrode in accordance with the increase of the voltage, so that the dust collecting space between the discharge electrode and the dust collecting electrode 122 It is filled by.

When the exhaust gas (the exhaust gas G1 in the example of FIG. 3) is introduced into the dust collecting space, the dust or mist in the exhaust gas is negatively charged and moves toward the dust collecting pole by the Coulomb force with electrostatic cohesion , And is attached to the dust collecting electrode (122). The attached dust or mist loses negative charge at the dust collecting electrode 122 and falls off from the dust collecting electrode 122 due to the washing water and the magnetic weight supplied to the dust collecting electrode 122 to be dropped by the wet electric dust collector 11).

Here, since Hg (2+) is a compound containing divalent mercury and is in the form of a solid dust or an aqueous solution mist, Hg (2+) is attached to the dust collecting electrode 122 on the same principle as dust or mist other than the above- .

In this manner, the wet electrostatic precipitator 11 can collect dusts of various kinds, including Hg (2+), with high dust collecting efficiency up to fine particles such as solid and liquid fine particles.

The exhaust gas (G2 in the example of FIG. 3) discharged to the outside of the wet electrostatic precipitator 11 is supplied to the drying tower or the like (not shown) through the exhaust gas discharge duct 12 of FIG. . That is, the exhaust gas introduced into the drying tower or the like contains almost no Hg.

[Review of suitable reagents]

Next, a specific example of a reagent for changing Hg (0) contained in the exhaust gas to Hg (2+) will be described.

The present inventors selected a suitable reagent, conducted a laboratory test using a simulated exhaust gas to obtain basic data, and conducted an actual instrument test using actual exhaust gas.

First, a laboratory test using a simulated exhaust gas will be described.

The present inventors prepared simulated exhaust gas by adding metal mercury as Hg to the cleaning bottle and ventilating the air, and adding about 15 vol% of SO 2 to air containing Hg vapor.

As a measuring apparatus for Hg, a measurement apparatus using a reduced vaporization atomic absorption method was employed. Also, the measurement in this case is only Hg (0). Thus, the generation (change) of Hg (2+) was determined as a decrease of Hg (0).

As described above, as a method for changing Hg (0) to Hg (2+) as described above, there are a first method using an oxidizing agent and a second method using a commonly used reducing agent to immobilize Hg. Here, the second method is employed, and candidates for the reagents employ KMnO 4 , NaHS, Na 2 S, HNO 3 , (NH 4 ) 2 S 2 O 8 , NaClO and H 2 O 2 .

First, as a laboratory test for the simulated gas in the first step, a test was conducted in which a reagent and a simulated gas were brought into contact with each other in a gas cleaning bottle to confirm the effect. Both SO 2 -free and SO 2 -free are used as the simulated gas.

The test results are shown in the following results (1) and (2).

Results (1): In the case of simulated gas of SO 2

Effective: KMnO 4 , NaClO

No effect: NaHS, Na 2 S, HNO 3 , (NH 4 ) 2 S 2 O 8 , H 2 O 2

Result (2): In case of simulated gas of SO 2

Effective: H 2 O 2 , Na 2 S, NaClO

No effect: KMnO 4, NaHS, (NH 4) 2 S 2 O 8, HNO 3

If more than clean, in the laboratory testing of a simulated gas of the second stage (gas washing bottle), KMnO 4, in the conditions of free SO 2 was shown a favorable effect, SO 2 was no significant conditions in effect.

In contrast, Na 2 S and H 2 0 2, the effect was not in the condition of free SO 2, SO 2 in the noted conditions are shown a good effect.

Next, as a laboratory test on the simulated gas in the second step, a test was conducted to confirm the effect by bringing the reagent into contact with the simulated gas by spraying the reagent. SO 2 oil was employed as the simulated gas.

As a result, H 2 O 2 , Na 2 S and NaClO were effective in the case of simulated SO 2 gas as in the first stage (gas scrubbing bottle). In addition, the degree of effect was higher in the second stage (spray spray) than in the first stage (gas scrubbing bottle). For this reason, in the above embodiment, a heavy metal removal supporting device 13 for spraying a reagent is employed.

In addition, KMnO 4 , NaHS, (NH 4 ) 2 S 2 O 8 , and HNO 3 were not effective in the case of simulated gas of SO 2 , as in the first stage (gas scrubbing bottle).

Next, in the dust collecting system 1 of Fig. 1, a test using an actual instrument was performed.

Specifically, in the dust collecting system 1 of FIG. 1, it is assumed that SO 2 is contained in the exhaust gas, so that H 2 O 2 , Na 2 S , and NaClO, which were effective in the above-mentioned laboratory test, .

1, the measurement point IN1 of the front end of the heavy metal removal support apparatus 13, the measurement point IN2 of the rear end of the heavy metal removal support apparatus 13 (inlet of the wet electrostatic precipitator 11) At the measurement point OUT of the outlet of the dust collector 11, the concentration of Hg (0) was measured.

As a result, the concentration of Hg (0) at the measurement point (OUT) was reduced by about -30% depending on the conditions, for H 2 O 2 , Na 2 S and NaClO.

From the above, H 2 O 2 , Na 2 S and NaClO are suitable as the reagent when SO 2 is contained in the exhaust gas.

[Effect of wet electrostatic precipitator of the present embodiment]

In summary, the dust collecting system 1 of the present embodiment can bring about the advantageous effects (1) and (2) as compared with the conventional dust collecting system.

(1) As described above, the heavy metal removal supporting device 13 is provided at the front end where the exhaust gas is introduced into the wet electrostatic precipitator 11. The heavy metal removal supporting apparatus 13 has a spray nozzle 23 for spraying a reagent having a property of changing Hg (0) to Hg (2+) against the exhaust gas.

Thereby, Hg (0) contained in the exhaust gas is converted into Hg (2+), and the exhaust gas is introduced into the wet electrostatic precipitator 11. Here, as described above, the wet electrostatic precipitator 11 has a function of removing Hg (2+). Therefore, in the wet electrostatic precipitator 11, Hg contained in the exhaust gas is removed.

Thus, mercury removal using the wet type wet electric dust collector 11 is realized.

(2) The exhaust gas of this embodiment contains SO 2 . In this case, by employing H 2 O 2 , Na 2 S, or NaClO as a reagent, mercury removal can be accurately performed as described above.

The present invention is not limited to the above-described embodiments, and variations, modifications, and the like within the scope of achieving the object of the present invention are included in the present invention.

For example, an inline mixer or baffle plate may be attached to the exhaust gas duct 12 downstream of the spray 23 to more efficiently promote the mixing (reaction) of the reagent and the exhaust gas sprayed by the spray 23 It is possible.

Further, for example, the wet electrostatic precipitator is not particularly limited to the wet electrostatic precipitator 11 described above, but it suffices that it has the following constitution, and various various embodiments can be adopted.

That is, the wet electrostatic precipitator installed at the rear end of the heavy metal removal supporting apparatus to which the present invention is applied,

A discharge electrode to which a DC high voltage is applied,

And the secondary corona discharge generated between the discharge electrodes based on the direct current high voltage causes the particulate contained in the exhaust gas discharged from the exhaust gas generating source and the dust collecting electrode

Is sufficient.

In addition, the dust collecting apparatus installed at the rear end of the heavy metal removal supporting apparatus to which the present invention is applied is not particularly required to be a wet type electric dust collecting apparatus, and various various embodiments can be adopted.

Further, for example, the heavy metal removal supporting apparatus to which the present invention is applied is not particularly limited to the heavy metal removal supporting apparatus 13 described above, and it suffices to have the following configuration, and various various embodiments can be adopted.

That is, the heavy metal removal supporting apparatus to which the present invention is applied includes:

The electric dust collecting apparatus having a configuration described in the preceding paragraph,

It suffices that the reagent having a property of changing the mercury of zero valence to divalent mercury has a spray portion for spraying the discharge gas.

In addition, the heavy metal removal supporting apparatus to which the present invention is applied diffuses the mercury in the gas phase into particulates by spraying a reagent having a property of changing the above-described zero-valent mercury into divalent mercury, (Nickel carbonate, cobalt carbonyl in nonferrous smelting), rare metals and noble metals are changed into particulate matter in addition to volatile harmful chloride and chloride in the gas phase, It can be collected by a dust collecting device.

That is, AsCl 3 (phosphorus trichloride arsenic), SnCl 4 [chloride, tin (IV)], S 2 Cl 2 ( dichloride disulfide), SiCl 4 (silicon tetrachloride, tetrachlorosilane), PCl 3 (phosphorus trichloride), and the like and non-ferrous Even at relatively low temperatures of about 50 degrees Celsius, which is the exhaust gas temperature used in the smelting off-gas treatment process, the vapor pressure is very high, i.e. volatile, and these harmful chlorides are present as gases in the offgas. Further, in the case where the exhaust gas temperature is near 100 degrees Celsius, the presence of gaseous harmful substances such as SbCl 3 (antimony trichloride), SeCl 4 (selenium tetrachloride), and PCl 5 (contaminated phosphorus) can not be ignored.

In addition, even in the presence of other than chloride, gaseous harmful substances such as nickel carbonyl (Ni (CO) 4 ) and cobalt carbonyl (Co (CO) 4 ) exist and these substances are removed by electrostatic precipitator Because it can not be captured), it was inevitable to give up removal.

However, by using the heavy metal removal supporting apparatus to which the present invention is applied, these harmful substances can be changed into particulate matter and collected by the dust collecting apparatus at the subsequent stage.

In addition to the above-mentioned point of view for removing harmful substances, rare metals or precious metals P, S, V, Cr, Zn, As, Se, Mo, Cd, Sn, Sb, A metal element selected from the group consisting of Te, W, Re, Os, Hg, Tl, Pb, Bi (phosphorus, sulfur, vanadium, chromium, zinc, arsenic, selenium, molybdenum, cadmium, tin, antimony, tellurium, tungsten, rhenium, , Lead, and bismuth) in a particulate state by oxidizing a gaseous metal and a gaseous chloride of the gaseous metal and the gaseous chloride in a particulate state by using a heavy metal removal supporting apparatus to which the present invention is applied, The rare metals and the noble metals can be reliably and efficiently recovered as oxides by the dust collecting device at the downstream end.

Specifically, for example, the reaction formula when AsCl 3 is oxidized by using NaClO, that is, ClO 2 - as an oxidizing agent, is as follows.

2 AsCl 3 + 5ClO - - > As 2 O 5 + 11Cl - (1)

Further, for example, as an oxidizing agent that is NaClO scheme in the case of oxidizing the SbCl 3 using hypochlorite ClO _ it is as follows.

2SbCl 3 + 5ClO - ? Sb 2 O 5 + 11Cl - (2)

The reaction formula when nickel carbonate (Ni (CO) 4 ) is oxidized using, for example, ClO - hypochlorous acid is as follows.

Ni (CO) 4 + 5ClO - → NiO + 4CO 2 + 5Cl - ··· (3)

Further, the reaction formula in the case of using nickel chloride (Ni (CO) 4 ) as a nickel chloride by using, for example, ClO 2 - hypochlorous acid is as follows.

Ni (CO) 4 + 4ClO - ? NiCl 2 + 4CO 2 + 2Cl - ????? (4)

In addition, both the equations (3) and (4) can be employed.

In the above example, the use of ClO < - > - hypochlorous acid as an oxidizing agent is mentioned, but it is not limited thereto. As the oxidizing agent to be used, an oxidizing agent selected from a chlorine-based material (ClO 2), an oxygen-based material (O 3 ozone-containing water, radical oxygen H 2 O 2 ) and a metal-based material (Mn, etc.) may be employed.

In addition, the oxidizing agent, as well as materials of sulfide to form a stable complex, e.g., the same effect using a PbS, ZnS, CuS, SnS, NiS, FeS, NaHS, Na 2 S, such as (change in the gaseous harmful substances in particle form Effect) can be obtained.

The method of removing harmful substances by contacting the liquid reagent with the exhaust gas as described above can be applied to a general gas cleaning tower (gas absorption tower, gas filled tower, wetted-wall tower, spray tower, foam bell tower, etc.) It can be carried out by a wet gas cleaning apparatus. However, as is well known, the pressure loss proportional to the power consumption of the wet scrubbing column is usually increased proportionally to the damping performance. That is, in order to obtain a high dust collection efficiency, it is necessary to apply a high pressure loss, and as a result, the operation cost becomes high.

For example, a particle having a particle diameter of less than 5 占 퐉 can not sufficiently remove a harmful substance in a spray column or the like having a relatively low energy consumption, and therefore, it has been necessary to use a Venturi scrubber apparatus that makes gas-liquid contact accompanied by a large pressure loss.

However, by combining a heavy metal removal supporting apparatus to which the present invention is applied and a wet electrostatic precipitator capable of removing particulate matter changed into particulate matter in the exhaust gas duct with a high efficiency of 99%, a wet cleaning apparatus such as a gas absorption tower, It is possible to efficiently realize the recovery of detoxification, vibration suppression, rare metals, and the like, which can be consumed in a large amount of electric power, with low consumption electric power consumption.

Here, in order to increase the gas-liquid contact efficiency, the smaller the particle diameter of the spray spraying reagent, the better. That is, since a spray with a particle diameter of about 400 to 1000 mu m (reagent droplet) having an average particle size of about 400 to 1000 mu m, which is used for producing a " wet wall " of a liquid spray in a spray tower or a wet electrostatic precipitator, The gas-liquid contact becomes insufficient.

Therefore, spray nozzles for spraying reagents used in the heavy metal removal supporting apparatus to which the present invention is applied preferably have an average particle diameter of 300 mu m or less (preferably 100 mu m or less).

1 ... dust collection system
11 ··· Sulfuric acid primary MC
12 ··· Exhaust gas introduction duct
13 · · Heavy metal removal support device
14 ... wet electrostatic precipitator
15 ... exhaust gas discharge duct
16 ... fan
21 ... reagent reservoir
22 ... fan
23 ... spray nozzle
24 ... coupling conduit
111 ... upper casing
113 ... lower casing
114 ... furniture
121 ... upper grid
122 ... dust collecting pole
123 ... lower grid
124 Electrode rod
125 ... the discharge wire
126 ... weight
127 ... Upward spray nozzle

Claims (5)

A discharge electrode to which a DC high voltage is applied,
And a dust collecting electrode for collecting mercury-containing heavy metal contained in the exhaust gas discharged from the discharge gas generating source by a negative corona discharge generated between the discharge electrodes based on the direct current high voltage.
And removing the heavy metal from the heavy metal,
Wherein the electric dust collecting apparatus further comprises:
A heavy metal removal supporting apparatus for an electric dust collector, comprising a spray portion for spraying a reagent having a property of changing heavy metal containing mercury into a form of increasing the dust collection rate at the dust collector compared to that before spraying, . 2. The apparatus of claim 1,
Wherein a reagent having a property of changing volatile harmful chloride, gaseous harmful substances, rare metals, and noble metals into a form of increasing the dust collection rate at the dust collector is sprayed to the exhaust gas. 2. The apparatus of claim 1,
Wherein a reagent having a property of changing the zero-valued gaseous mercury into bivalent mercury is sprayed onto the exhaust gas. 4. The method according to any one of claims 1 to 3,
Said exhaust gas comprising SO 2 ,
Wherein the reagent is Na 2 S, NaClO or H 2 O 2 . 4. The method according to any one of claims 1 to 3,
Wherein the reagent is a sulfide forming a stable complex.
KR1020177029313A 2015-03-26 2016-03-25 Heavy metal removal support device for electric dust collector KR20170125968A (en)

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CN113351370B (en) * 2021-06-30 2023-04-07 上海电力大学 Composite electrostatic dust collection device for removing arsenic, selenium and lead in flue gas
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JPS62286562A (en) * 1986-06-04 1987-12-12 Sumitomo Metal Mining Co Ltd Removal of mercury in exhaust gas
JPH0889757A (en) * 1994-09-26 1996-04-09 Babcock Hitachi Kk Treatment of waste gas from refuse incineration furnace
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CN1219580C (en) * 2003-07-30 2005-09-21 浙江大学 Coal-fired mercury discharge control method based on semi-dry process
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