KR101974008B1 - Wet type electrostatic precipitator combined with calcium carbonate manufacturing equipment and fine dust removal method using the same - Google Patents

Abstract

The present invention relates to a wet electrostatic precipitator to which a calcium carbonate production apparatus is combined and a method for removing fine dust using the same. More particularly, the present invention relates to a wet electrostatic precipitator using a fly ash and carbon dioxide discharged from a thermal power plant, The present invention relates to a wet electrostatic precipitator and a fine dust removing method using the same, which are combined with a calcium carbonate production apparatus capable of effectively removing fine dust. To this end, a wet electrostatic precipitator incorporating a calcium carbonate manufacturing apparatus includes a calcium ion extracting unit for extracting calcium ions contained in fly ash by mixing fly ash and water; A carbonation reaction unit for supplying a calcium ion extraction aqueous solution from the calcium ion extraction unit and mixing it with carbon dioxide to produce calcium carbonate; And a wet electrostatic precipitator provided on the upper part of the calcium ion extracting part, for receiving the calcium ion extraction aqueous solution from the calcium ion extracting part, and spraying the calcium ion extracting aqueous solution to remove fine dust therefrom.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wet electrostatic precipitator and a fine dust removing method using the wet electrostatic precipitator. 2. Description of the Related Art [0002]

The present invention relates to a wet electrostatic precipitator to which a calcium carbonate production apparatus is combined and a method for removing fine dust using the same. More particularly, the present invention relates to a wet electrostatic precipitator using a fly ash and carbon dioxide discharged from a thermal power plant, The present invention relates to a wet electrostatic precipitator and a fine dust removing method using the same, which are combined with a calcium carbonate production apparatus capable of effectively removing fine dust.

Nuclear power generation has been spotlighted over the past decade as part of the power generation to cope with global warming caused by carbon dioxide. However, due to frequent natural disasters, safety has become a problem, and countries are reserving or canceling new construction. Therefore, dependence on thermal power generation is expected to increase for a long time in the absence of an alternative energy source. However, power generation by thermal power generation also has various problems related to environmental pollution. As a typical problem, there is a problem of discharging NO _x gas, SO _x gas, dust and the like. In recent years, there is introduced a wide variety of facilities in order to solve such a problem, for example, by installing a SCR (selective catalystic reduction) device to remove the NO _x gas, and installing the FGD (flue gas desulfurization) unit the SO _x gas And the dust is removed using a dry electrostatic precipitator. However, one of the major problems that remains unresolved is the massive emission of carbon dioxide.

Meanwhile, 'fly ash' is generated in a large amount during the combustion and incineration of the fuel. Fly ash contains various components such as calcium and silica depending on the burned material, and the composition ratio is also very various. However, since fly ash has little value in its use and is alkaline, it is being loaded around combustion and incineration facilities, which is another big problem due to thermal power generation.

In addition, recently, people from China are directly experiencing the seriousness of fine dust (especially, PM 2.5 or less), and removal of fine dust by thermal power generation is also a serious problem to be solved.

In order to solve these problems, various solutions have been sought, and a wet electrostatic precipitator has been introduced into a thermal power plant to remove fine dust. However, the above problems are not solved in a complex manner, Fly ash, and technology to effectively remove fine dust are required to be developed.

Korean Patent Publication No. 10-2013-0017453

SUMMARY OF THE INVENTION It is an object of the present invention to provide a wet electrostatic precipitator incorporating a calcium carbonate production device capable of effectively removing fly ash, carbon dioxide, fine dust, And to provide a method for removing fine dust.

These and other objects and advantages of the present invention will become apparent from the following description of a preferred embodiment.

The above object can be accomplished by a calcium ion extraction unit for extracting calcium ions contained in fly ash by mixing fly ash and water; A carbonation reaction unit for supplying a calcium ion extraction aqueous solution from the calcium ion extraction unit and mixing it with carbon dioxide to produce calcium carbonate; And a wet electrostatic precipitator installed at an upper portion of the calcium ion extracting portion and supplied with a calcium ion extraction aqueous solution from the calcium ion extracting portion and spraying the calcium ion extracted aqueous solution to remove fine dust therefrom, Lt; / RTI >

Preferably, the calcium ion extraction unit may include an exhaust gas supply unit for supplying an exhaust gas containing carbon dioxide, and a pH control unit for supplying the acidic substance to adjust the pH of the calcium ion extraction aqueous solution. with an acidic material, nitric acid (HNO _3), hydrochloric acid (HCl), sulfuric acid (H ₂ SO _4), hydrogen bromide (HBr), iodine hydrogen (HI), perchloric acid (HClO ₄₎ and phosphoric acid (H ₃ PO ₄₎ And the like.

The calcium ion extraction unit may include a ligand supply unit for supplying a ligand for separating the extracted calcium ions, wherein the ligand is selected from the group consisting of acetic acid (CH ₃ COOH), carboxyglutamic acid (C ₆ H ₉ NO ₆ ) , Nitrobenzene (C ₆ H ₅ NO ₂ ), iminodiacetic acid (HN (CH ₂ CO ₂ H) ₂ ), citrate, glutamate and oxalic acid (C ₂ H ₂ O ₄ ) And the like.

The calcium ion extraction unit may include a pump for supplying the calcium ion extraction aqueous solution to the wet electrostatic precipitator located at the upper portion of the calcium ion extraction unit and may include a stirring device for stirring the fly ash and water .

Preferably, the carbonation reaction unit may include a filter for removing impurities in the calcium ion extraction aqueous solution supplied from the calcium ion extraction unit, a pH controller for supplying a basic substance to adjust the pH of the aqueous calcium extraction solution; It can include, and, at this time, the basic substance, may be at least one selected from the group consisting of sodium hydroxide (NaOH), calcium hydroxide (KOH) and ammonium hydroxide (NH ₄ OH).

The carbonation reaction unit may include a stirring device for stirring the calcium ion extraction aqueous solution and a calcium carbonate discharging unit for separating and discharging the produced calcium carbonate in the lower part. And a gas discharge port for discharging the gas.

Preferably, the wet electrostatic precipitator further comprises: a discharge electrode for charging an exhaust gas containing fine dust; And a dust collecting electrode collecting the charged fine dust.

In addition, the wet electrostatic precipitator may include a jetting section including a jetting nozzle for jetting a calcium ion extraction aqueous solution, and preferably includes two jetting sections arranged vertically, and the jetting section disposed on the upper side includes a discharge electrode The jetting portion disposed on the lower side of the dust collecting electrode may be positioned below the discharge electrode and the dust collecting electrode.

The wet electrostatic precipitator may further include a gas outlet for discharging the purified gas to the upper portion.

The above object can also be achieved by a method for producing a calcium ion, comprising: a calcium ion extraction step of mixing fly ash and water to extract calcium ions contained in fly ash; A carbonation step of supplying calcium ion extraction aqueous solution produced by the calcium ion extraction step and mixing calcium carbonate with carbon dioxide to produce calcium carbonate; And a wet electrostatic precipitating step of spraying a calcium ion extraction aqueous solution produced by the calcium ion extraction step to remove fine dust.

In this case, the calcium ion extraction step may include an exhaust gas supplying step of supplying an exhaust gas containing carbon dioxide, and a pH controlling step of supplying an acidic substance to adjust the pH of the aqueous calcium extraction solution. And a ligand supplying step of supplying a ligand for separating the extracted calcium ions, and a stirring step of stirring the fly ash and water.

The carbonation step may include a filtration step of removing impurities in the calcium ion extraction aqueous solution when the calcium ion extraction aqueous solution produced by the calcium ion extraction step is supplied, And a pH controlling step of adjusting the pH of the aqueous solution, wherein the calcium carbonate extracting step may include a stirring step for stirring the calcium ion extract aqueous solution, and a calcium carbonate discharging step for separating and discharging the calcium carbonate produced And a gas discharging step for discharging the purified gas.

In addition, the wet electrostatic precipitating step may include a discharging step of charging the exhaust gas containing the fine dust; And a dust collecting step of collecting the charged fine dust, and a gas discharging step of discharging the purified gas.

According to the present invention, a calcium carbonate production apparatus and a wet electrostatic precipitator are integrally formed, so that calcium carbonate can be produced using carbon dioxide and fly ash discharged from a thermal power plant, and the fine dust can be effectively removed .

Specifically, calcium ions are extracted from fly ash, mixed with carbon dioxide to produce calcium carbonate, and at the same time, a calcium ion extraction aqueous solution is supplied to a wet electrostatic precipitator and sprayed to remove fine dust.

However, the effects of the present invention are not limited to the above-mentioned effects, and other effects not mentioned can be clearly understood by those skilled in the art from the following description.

1 is a schematic view of a thermal power generation apparatus according to an example.
2 is a schematic view of a wet electrostatic precipitator incorporating an apparatus for producing calcium carbonate according to an embodiment of the present invention.

Hereinafter, the present invention will be described in detail with reference to embodiments and drawings of the present invention. It will be apparent to those skilled in the art that these embodiments are provided by way of illustration only for the purpose of more particularly illustrating the present invention and that the scope of the present invention is not limited by these embodiments .

Also, unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains and, where contradictory, Will be given priority.

In order to clearly illustrate the claimed invention, parts not related to the description are omitted, and like reference numerals are used for like parts throughout the specification. And, when a section is referred to as " including " an element, it does not exclude other elements unless specifically stated to the contrary. In addition, " part " described in the specification means one unit or block performing a specific function.

In each step, the identification code (first, second, etc.) is used for convenience of explanation, the identification code does not describe the order of each step, and each step does not explicitly list a specific order in the context May be performed differently from the above-described sequence. That is, each of the steps may be performed in the same order as described, or may be performed substantially concurrently or in the reverse order.

1 is a schematic view of a thermal power generation apparatus according to an example including a boiler 100, an SCR apparatus 200, an ESP apparatus 300, an FGD apparatus 400, and a stack 500, 1 is a schematic view of a wet electrostatic precipitator incorporating an apparatus for producing calcium carbonate according to an embodiment of the present invention; 1 and 2, a wet electrostatic precipitator incorporating an apparatus for producing calcium carbonate according to an embodiment of the present invention mixes fly ash and water to form a calcium ion for extracting calcium ions contained in fly ash An extracting unit 10; A carbonation reaction unit 20 for supplying a calcium ion extraction aqueous solution from the calcium ion extraction unit 10 and mixing it with carbon dioxide to produce calcium carbonate; And a wet electrostatic precipitator (30) installed on the upper part of the calcium ion extracting part (10), for receiving the calcium ion extraction aqueous solution from the calcium ion extracting part (10) and spraying it to remove fine dust. The present invention can be applied to the thermal power generation apparatus shown in FIG. 1, in which a calcium carbonate production apparatus and a wet type electrostatic precipitator 30 are integrally formed, and calcium carbonate is produced using carbon dioxide and fly ash discharged from a thermal power plant In addition, fine dust discharged from the thermal power plant can be effectively removed by supplying the aqueous solution extracted with the calcium ions generated by the calcium ion extraction unit 10 to the wet electrostatic precipitator 30 and spraying the same.

In one embodiment, the calcium ion extraction unit 10 receives the fly ash from the fly ash supply unit 11, receives water from the water supply unit 12, and mixes the water, thereby extracting the calcium ions contained in the fly ash. Aqueous solution of calcium ion extraction. The fly ash supplying unit 11 is connected to the dry type ESP apparatus 300 installed in the thermal power plant and supplies the fly ash contained in the exhaust gas from which dust has been removed by the ESP apparatus 300 to the calcium ion extracting unit 10 .

At this time, the calcium ion extraction unit 10 may include an exhaust gas supply unit 13. The exhaust gas supply unit 13 can supply the exhaust gas containing carbon dioxide to the calcium ion extraction unit 10. Generally, the flue gas passed through the FGD device 400 contains about 15% or less of carbon dioxide. If the flue gas is directly discharged into the air, it may cause environmental pollution such as global warming. Accordingly, the present invention utilizes the carbon dioxide-containing exhaust gas as a means for lowering the acidity by guiding the exhaust gas into the calcium ion extraction unit 10. That is, the exhaust gas supply unit 13 may be formed on one side of the calcium ion extraction unit 10, and connected to a flue gas desulfurization (FGD) apparatus installed in the thermal power plant to remove the SO _x gas, Can be supplied to the calcium ion extracting section (10).

In one embodiment, the calcium ion extraction unit 10 may include a pH control unit 14. The pH controller 14 can adjust the pH of the calcium ion extraction aqueous solution to 4 to 6.5 by using carbon dioxide or the like supplied to the calcium ion extracting unit 10.

In addition, the pH control unit 14 may adjust the pH of the calcium ion extraction aqueous solution to 2 to 6 by supplying an acidic substance to the calcium ion extraction unit 10 in order to effectively extract calcium ions from the fly ash, if necessary. At this time, the acidic substance for controlling the acidity is acidic substance such as nitric acid (HNO ₃ ), hydrochloric acid (HCl), sulfuric acid (H ₂ SO ₄ ), hydrogen bromide (HBr), hydrogen iodide (HI), perchloric acid (HClO ₄ ) H ₃ PO ₄ ), but the present invention is not limited thereto.

In one embodiment, the calcium ion extraction unit 10 may include a ligand supply unit 15. The ligand supply unit 15 is connected to the water supply unit 12 and can supply the ligand together when water is supplied to the calcium ion extraction unit 10. A ligand is a molecule or ion coordinating to a central metal ion in a complex, and is characterized in that it has a pair of unshared electrons in order to coordinate with a metal ion. Since the ligand can selectively bind to the metal ion, the ligand can selectively bind to the extracted calcium ion, so that the extracted calcium ion can be effectively separated from other extracted metal ions except for the calcium ion. In this case, the ligand is acetic acid (CH ₃ COOH), carboxyethyl-glutamic acid _{(C 6 H 9 NO 6)} , nitrobenzene _{(C 6 H 5 NO 2)} , iminodiacetic acid _{(HN (CH 2 CO 2 H} ) 2), citrate At least one selected from the group consisting of citrate, glutamate and oxalic acid (C ₂ H ₂ O ₄ ) can be used, but not limited thereto, and any ligands capable of selectively binding to calcium ions can be used .

In one embodiment, the calcium ion extraction section 10 may include a pump 16. The pump 16 serves to supply a calcium ion extraction aqueous solution to the wet electrostatic precipitator 30 to be described later. The pump 16 is used to effectively supply the calcium ion extraction aqueous solution to the wet electrostatic precipitator 30 located above the calcium ion extractor, and various known pumps 16 may be used.

In one embodiment, the calcium ion extraction section 10 may include an agitation device 17. The stirring device 17 may be an agitator having a plurality of rotating blades for effectively increasing the extraction efficiency of calcium ions by effectively stirring fly ash and water. However, the stirring device 17 is not limited to this, have.

In one embodiment, the calcium ion extraction unit 10 may include a residue collection unit at the bottom. The residue collecting part collects residues encompassing all the particles other than calcium ions such as metal ions other than calcium ions or fine dust, and may include various filtration devices. By using the filtration device, the residue can be effectively recovered and separated can do.

In one embodiment, the carbonation reaction unit 20 can produce calcium carbonate by supplying a calcium ion extraction aqueous solution from the calcium ion extraction unit 10 and mixing it with carbon dioxide. The carbon dioxide can be supplied from the carbon dioxide supply unit 21 connected to the stack 500. That is, the carbon dioxide supply unit 21 is not removed during the process, but the carbon dioxide discharged to the outside through the stack 500 is recovered from the stack 500 and supplied to the carbonation reaction unit 20, It is possible to prevent environmental pollution.

In one embodiment, the carbonation reaction unit 20 may include a filter 22 for removing impurities in the calcium ion extraction aqueous solution at a portion connected to the calcium ion extractor. The filter 22 may be any of various known filtration membranes capable of selectively passing calcium ions.

In one embodiment, the carbonation reaction section 20 may include a pH control section 23. The pH controller 23 controls the pH of the aqueous solution of calcium ion extraction to be basic by supplying a basic substance to the carbonation reaction unit 20, and in order to produce calcium carbonate, it is important to make a solution containing calcium ions into a basic condition , And it is preferable to adjust the pH to 8 to 12. Basic materials for making basic conditions include sodium hydroxide (NaOH), calcium hydroxide (KOH), ammonium hydroxide (NH ₄ OH), and the like, but not limited thereto, and various known basic materials can be used.

In one embodiment, the carbonation reaction section 20 may include an agitation device 24. The stirrer 24 is for producing calcium carbonate by effectively stirring calcium ion extraction aqueous solution and carbon dioxide, and may be a Taylor vortex reactor. However, it is not limited to this, and it is possible to effectively mix calcium ions and carbon dioxide gas Can be used.

In one embodiment, the carbonation reaction section 20 may include a calcium carbonate discharge section at the bottom. When calcium ions and carbon dioxide are stirred in the carbonation reaction unit 20, calcium carbonate in a slurry form is produced. The calcium carbonate discharge unit can effectively separate and discharge calcium carbonate using various filtration apparatuses. Generally, since the size of the carbonate exceeds 40 mu m, it is preferable to use a filter apparatus including a plurality of pores having a diameter of 30 to 40 mu m.

In one embodiment, the carbonation reactor 20 may include a gas outlet 25 at the top. The gas exhaust port 25 is connected to the stack 500 and removes carbon dioxide, fine dust, and the like, so that the purified gas is discharged to the stack 500 and finally discharged to the outside through the stack 500. Here, the purified gas means a relatively clean gas from which carbon dioxide, fine dust, and the like are removed as compared with the exhaust gas supplied to the first calcium ion extraction unit 10.

In one embodiment, the wet electrostatic precipitator 30 is installed on the upper part of the calcium ion extraction unit 10, and receives the calcium ion extraction aqueous solution from the calcium ion extraction unit 10, And is characterized in that a calcium ion extraction aqueous solution produced in the calcium ion extraction section 10 is used. Specifically, the wet electrostatic precipitator 30 is installed on the upper part of the calcium ion extracting unit 10 and injects the calcium ion extracted aqueous solution supplied from the calcium ion extracting unit 10 downward to the calcium ion extracting unit 10 When the supplied exhaust gas rises, fine dust contained in the exhaust gas can be removed. The removed fine dust is finally removed by the residue collecting part.

In one embodiment, the wet electrostatic precipitator (30) includes a discharge electrode (31) for charging an exhaust gas (dust) including fine dust particles; And a dust collecting electrode 32 for collecting the charged fine dust. At this time, a plurality of the discharge electrodes 31 and the dust collecting electrodes 32 may be provided. The discharge electrode 31 functions as a negative electrode by applying a high voltage of negative (-) and generates a corona discharge to charge particles in the exhaust gas, and a product made of Corten steel can be used. (+) High voltage is applied to the dust collecting electrode 32 to function as a positive electrode, and the charged particles (fine dust) can be collected by the Coulomb force.

In one embodiment, the wet electrostatic precipitator 30 may include a jetting portion 33. The jetting section 33 is for jetting the calcium ion extraction aqueous solution supplied from the calcium ion extracting section 10 downward and may include the jetting nozzle 34. A plurality of injection nozzles 34 may be provided. In addition, the wet electrostatic precipitator 30 may include a plurality of jetting portions 33, and preferably includes at least two jetting portions 33 arranged at the top and bottom. At this time, the jetting section 33 disposed on the upper side is located above the discharge electrode 31 and the dust collecting electrode 32, and the jetting section 33 disposed on the lower side is located below the discharge electrode 31 and the dust collecting electrode 32 .

The wet electrostatic precipitator 30 may include a jetting section control section for controlling the jetting operation of the jetting section 33. The jetting section control section controls the operation of one or a plurality of jetting sections 33 and includes two jetting sections 33 arranged on the upper and lower parts of the discharge electrode 31 and the collecting electrode 32, By controlling the jetting section 33 disposed on the upper side to jet intermittently (for example, one minute), the fine dust collected on the dust collecting electrode 32 is washed away and the jetting section 33 ) Is continuously sprayed to directly remove fine dust inside the flue gas (dust) coming up. The removed fine dust returns to the calcium ion extracting section 10 and can finally be removed by the residue collecting section.

In one embodiment, the wet electrostatic precipitator 30 may include a gas outlet 35 at the top. The gas discharge port 35 is connected to the stack 500 and discharges the cleaned gas to the stack 500 after the fine dust or the like is removed and finally discharged to the outside through the stack 500. Here, the purified gas refers to a gas that is relatively clean when carbon dioxide or the like is removed as compared with the exhaust gas supplied to the first calcium ion extraction unit 10.

Next, the fine dust removing method will be described. For convenience of explanation, the wet electrostatic precipitator incorporating the above-described apparatus for producing calcium carbonate will be described as an example, but the present invention is not limited thereto. In the following description, duplicated description will be omitted.

A method for removing fine dust according to an embodiment of the present invention includes: a calcium ion extraction step of extracting calcium ions contained in fly ash by mixing fly ash and water; A carbonation step of supplying calcium ion extraction aqueous solution produced by the calcium ion extraction step and mixing calcium carbonate with carbon dioxide to produce calcium carbonate; And a wet electrostatic precipitating step of spraying a calcium ion extraction aqueous solution produced by the calcium ion extraction step to remove fine dust. The present invention can not only produce carbon dioxide from carbon dioxide and fly ash generated in a thermal power generation apparatus, but also can effectively remove fine dust by using a calcium ion extraction aqueous solution produced in the process of producing calcium carbonate.

In one embodiment, the calcium ion extraction step may be performed by supplying fly ash from the fly ash supply unit 11, supplying water from the water supply unit 12, and mixing the calcium ions to the calcium ion extracted calcium ions contained in the fly ash An extraction aqueous solution can be produced.

At this time, the calcium ion extraction step may include an exhaust gas supply step. The exhaust gas supplying step may supply the exhaust gas containing carbon dioxide to the calcium ion extracting section 10. Generally, the flue gas passed through the FGD device 400 contains about 15% or less of carbon dioxide. If the flue gas is directly discharged into the air, it may cause environmental pollution such as global warming. Accordingly, the present invention utilizes the carbon dioxide-containing exhaust gas as a means for lowering the acidity by guiding the exhaust gas into the calcium ion extraction unit 10.

In one embodiment, the calcium ion extraction step may comprise a pH control step. In the pH control step, the pH of the calcium ion extraction aqueous solution can be adjusted to 4 to 6.5 by using carbon dioxide or the like supplied to the calcium ion extraction unit 10.

In the pH control step, the pH of the calcium ion extraction aqueous solution may be adjusted to 2 to 6 by supplying an acidic substance to the calcium ion extraction unit 10 to effectively extract calcium ions from the fly ash, if necessary. At this time, the acidic substance for controlling the acidity is acidic substance such as nitric acid (HNO ₃ ), hydrochloric acid (HCl), sulfuric acid (H ₂ SO ₄ ), hydrogen bromide (HBr), hydrogen iodide (HI), perchloric acid (HClO ₄ ) H ₃ PO ₄ ), but the present invention is not limited thereto.

In one embodiment, the calcium ion extraction step may comprise a ligand feed step. The ligand supplying step may supply the ligand together when water is supplied to the calcium ion extracting unit 10. [ A ligand is a molecule or ion coordinating to a central metal ion in a complex, and is characterized in that it has a pair of unshared electrons in order to coordinate with a metal ion. Since the ligand can selectively bind to the metal ion, the ligand can selectively bind to the extracted calcium ion, so that the extracted calcium ion can be effectively separated from other extracted metal ions except for the calcium ion. In this case, the ligand is acetic acid (CH ₃ COOH), carboxyethyl-glutamic acid _{(C 6 H 9 NO 6)} , nitrobenzene _{(C 6 H 5 NO 2)} , iminodiacetic acid _{(HN (CH 2 CO 2 H} ) 2), citrate At least one selected from the group consisting of citrate, glutamate and oxalic acid (C ₂ H ₂ O ₄ ) can be used, but not limited thereto, and any ligands capable of selectively binding to calcium ions can be used .

In one embodiment, the calcium ion extraction step may comprise a stirring step. The stirring step is a step for effectively stirring the fly ash and the water to improve the extraction efficiency of calcium ions. The stirrer having a plurality of rotating blades may be used, but not limited thereto, and various known stirrers may be used.

In one embodiment, the calcium ion extraction step may comprise a residue recovery step. The residue recovering step is a step of recovering residues including all of the metal ions other than calcium ions and particles other than calcium ions such as fine dusts, and it is possible to effectively collect and separate the residues using various filtration apparatuses.

In one embodiment, the carbonation step may be performed by mixing the calcium ion extraction aqueous solution produced by the calcium ion extraction step with carbon dioxide. The carbon dioxide can be supplied from the carbon dioxide supply unit 21 connected to the stack 500. Further, the carbonation step may include a filtration step of removing impurities in the calcium ion extraction aqueous solution when the calcium ion extraction aqueous solution produced by the calcium ion extraction step is supplied. As the filtration step, various known filtration membranes capable of selectively passing calcium ions can be used.

In one embodiment, the carbonation step may comprise a pH control step. The pH control step is a step of adjusting the pH of the aqueous solution of calcium ion extraction to a basic level by supplying a basic substance. In order to prepare calcium carbonate, it is important to make a solution containing calcium ions in a basic condition, . Basic materials for making basic conditions include sodium hydroxide (NaOH), calcium hydroxide (KOH), ammonium hydroxide (NH ₄ OH), and the like, but not limited thereto, and various known basic materials can be used.

In one embodiment, the carbonation step may comprise an agitation step. The stirring step is a step for producing calcium carbonate by effectively stirring calcium ion extraction aqueous solution and carbon dioxide. The Taylor vortex reactor may be used, but the present invention is not limited to this, and it is possible to use a known variety of calcium ions A stirrer can be used.

In one embodiment, the carbonation step may include a calcium carbonate discharge step. When calcium ions and carbon dioxide are stirred in the carbonation step, calcium carbonate in the form of slurry is produced. In the step of discharging calcium carbonate, calcium carbonate can be effectively separated and discharged using various filtration apparatuses. Generally, since the size of the carbonate exceeds 40 mu m, it is preferable to use a filter apparatus including a plurality of pores having a diameter of 30 to 40 mu m.

In one embodiment, the carbonation step may comprise a step of venting gas. The gas exhausting step removes carbon dioxide, fine dust, and the like, so that the purified gas is discharged to the stack 500 and finally discharged to the outside through the stack 500. Here, the purified gas means a relatively clean gas from which carbon dioxide, fine dust, and the like are removed as compared with the exhaust gas supplied to the first calcium ion extraction unit 10.

In one embodiment, the wet electrostatic precipitating step is a step of spraying a calcium ion extraction aqueous solution produced by the calcium ion extraction step to remove fine dust, and the fine electrostatic precipitating step may be performed by using a calcium ion extraction aqueous solution produced by the calcium ion extraction step Thereby removing dust. Specifically, in the wet electrostatic precipitating step, the calcium ion extraction aqueous solution is supplied from the calcium ion extraction unit 10 to the wet electrostatic precipitator 30, and then sprayed in the downward direction, whereby the exhaust gas supplied to the calcium ion extraction unit 10 rises It is possible to remove fine dust and the like contained in the exhaust gas. The removed fine dust is finally removed at the residue recovery step.

In one embodiment, the wet electrostatic precipitator comprises a discharging step of charging an exhaust gas (dust) containing fine dust; And a dust collecting step of collecting the charged fine dust. The wet electrostatic precipitating step may also include a gas evacuation step. In the gas discharging step, the cleaned gas is removed from the stack 500 by removing fine dust or the like, and finally discharged to the outside through the stack 500. Here, the purified gas refers to a gas that is relatively clean when carbon dioxide or the like is removed as compared with the exhaust gas supplied to the first calcium ion extraction unit 10.

It is to be understood that the present invention is not limited to the above embodiments and various changes and modifications may be made by those skilled in the art without departing from the spirit and scope of the invention.

100: boiler 200: SCR device
300: ESP device 400: FGD device
500: stack
10: Calcium ion extraction unit 11: Fly ash supply unit
12: Water supply part 13: Flue gas supply part
14: pH control unit 15: ligand supply unit
16: pump 17: stirring device
20: carbonation reaction part 21: carbon dioxide supply part
22: filter 23: pH controller
24: stirrer 25: gas outlet
30: wet electrostatic precipitator 31: discharge electrode
32: dust collecting electrode 33:
34: injection nozzle 35: gas outlet

Claims (30)

A calcium ion extracting unit for extracting calcium ions contained in fly ash by mixing fly ash and water;
A carbonation reaction unit for supplying a calcium ion extraction aqueous solution from the calcium ion extraction unit and mixing it with carbon dioxide to produce calcium carbonate; And
And a wet electrostatic precipitator installed at an upper portion of the calcium ion extracting portion to receive a calcium ion extraction aqueous solution from the calcium ion extracting portion and spray the same to remove fine dust,
The calcium ion extraction unit includes a pH control unit for supplying an acidic substance to adjust the pH of the calcium ion extraction aqueous solution to 2 to 6,
Wherein the carbonation reaction unit comprises a pH control unit for supplying a basic substance to adjust the pH of the calcium ion extraction aqueous solution to 8 to 12. The wet electrostatic precipitator according to claim 1, The calcium ion extraction device according to claim 1,
And an exhaust gas supply unit for supplying an exhaust gas containing carbon dioxide. delete The method of claim 1,
Nitric acid (HNO _3), hydrochloric acid (HCl), sulfuric acid (H ₂ SO _4), hydrogen bromide (HBr), iodine hydrogen (HI), perchloric acid (HClO ₄₎ and phosphoric acid (H ₃ PO _4), selected from the group consisting of Wherein the calcium carbonate production device is at least one of the calcium carbonate production device and the calcium carbonate production device. The calcium ion extraction device according to claim 1,
And a ligand supply unit for supplying a ligand for separating the extracted calcium ions. ≪ Desc / Clms Page number 20 > 6. The method of claim 5,
Acetic acid (CH ₃ COOH), carboxyethyl-glutamic acid _{(C 6 H 9 NO 6)} , nitrobenzene _{(C 6 H 5 NO 2)} , iminodiacetic acid _{(HN (CH 2 CO 2 H} ) 2), citrate (Citrate), Wherein the calcium carbonate production apparatus is at least one selected from the group consisting of glutamate and oxalic acid (C ₂ H ₂ O ₄ ). The calcium ion extraction device according to claim 1,
And a pump for supplying a calcium ion extraction aqueous solution to a wet electrostatic precipitator located above the calcium ion extraction unit. The calcium ion extraction device according to claim 1,
And a stirring device for stirring the fly ash and the water. The method according to claim 1,
And a filter for removing impurities in the calcium ion extraction aqueous solution supplied from the calcium ion extraction unit. delete The method according to claim 1,
Sodium hydroxide (NaOH), calcium hydroxide (KOH) and ammonium hydroxide (NH ₄ OH) to at least any one of to, characterized in that the combined wet electrostatic precipitator calcium carbonate producing apparatus device selected from the group consisting of. The method according to claim 1,
And a stirring device for stirring the calcium ion extraction aqueous solution. ≪ Desc / Clms Page number 20 > The method according to claim 1,
And a calcium carbonate discharging unit for separating and discharging the calcium carbonate produced in the lower part of the wet electrostatic precipitator. The method according to claim 1,
And a gas outlet for discharging the purified gas to the upper portion of the wet electrostatic precipitator. The wet electrostatic precipitator according to claim 1,
A discharge electrode for charging an exhaust gas containing fine dust; And
And a dust collecting electrode for collecting the charged fine dust. 16. The wet electrostatic precipitator of claim 15,
And a jetting unit including a jet nozzle for jetting a calcium ion extraction aqueous solution. 17. The wet electrostatic precipitator of claim 16,
And two jetting portions arranged in the vertical direction,
Wherein the jetting portion disposed on the upper side is located above the discharge electrode and the dust collecting electrode and the jetting portion disposed on the lower side is located below the discharge electrode and the dust collecting electrode. The wet electrostatic precipitator according to claim 1,
And a gas outlet for discharging the purified gas to the upper portion of the wet electrostatic precipitator. A method for removing fine dust using a wet electrostatic precipitator combined with the apparatus for producing calcium carbonate according to claim 1,
A calcium ion extraction step of extracting calcium ions contained in fly ash by mixing fly ash and water;
A carbonation step of supplying calcium ion extraction aqueous solution produced by the calcium ion extraction step and mixing calcium carbonate with carbon dioxide to produce calcium carbonate; And
And a wet electrostatic precipitator step of spraying a calcium ion extraction aqueous solution produced by the calcium ion extraction step to remove fine dust. 20. The method of claim 19,
And a flue gas supplying step of supplying flue gas containing carbon dioxide. 20. The method of claim 19,
And a pH control step of supplying an acidic substance to adjust the pH of the calcium ion extraction aqueous solution. 20. The method of claim 19,
And a ligand supplying step of supplying a ligand for separating the extracted calcium ions. 20. The method of claim 19,
And a stirring step of stirring the fly ash and the water. 20. The method of claim 19,
And a filtration step of removing impurities in the calcium ion extraction aqueous solution when the calcium ion extraction aqueous solution produced by the calcium ion extraction step is supplied. 20. The method of claim 19,
And a pH control step of supplying a basic substance to adjust the pH of the calcium ion extraction aqueous solution. 20. The method of claim 19,
And a stirring step for stirring the calcium ion extraction aqueous solution. 20. The method of claim 19,
And a calcium carbonate discharging step of separating and discharging the manufactured calcium carbonate. 20. The method of claim 19,
And a gas discharging step of discharging the purified gas. 20. The method of claim 19,
A discharging step of charging an exhaust gas containing fine dust; And
And a dust collecting step of collecting the charged fine dust. 20. The method of claim 19,
And a gas discharging step of discharging the purified gas.

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