WO2023003104A1 - Exhaust gas processing system comprising desulfurization and denitrification - Google Patents

Exhaust gas processing system comprising desulfurization and denitrification Download PDF

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Publication number
WO2023003104A1
WO2023003104A1 PCT/KR2021/018865 KR2021018865W WO2023003104A1 WO 2023003104 A1 WO2023003104 A1 WO 2023003104A1 KR 2021018865 W KR2021018865 W KR 2021018865W WO 2023003104 A1 WO2023003104 A1 WO 2023003104A1
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Prior art keywords
aqueous solution
exhaust gas
desulfurization
denitrification
storage tank
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PCT/KR2021/018865
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French (fr)
Korean (ko)
Inventor
김학준
이예완
김용진
한방우
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Korea Institute of Machinery and Materials KIMM
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Korea Institute of Machinery and Materials KIMM
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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
    • B01D53/60—Simultaneously removing sulfur oxides and nitrogen oxides
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D47/00—Separating dispersed particles from gases, air or vapours by liquid as separating agent
    • B01D47/06—Spray cleaning
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D47/00—Separating dispersed particles from gases, air or vapours by liquid as separating agent
    • B01D47/06—Spray cleaning
    • B01D47/063—Spray cleaning with two or more jets impinging against each other
    • 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
    • B01D53/78—Liquid phase processes with gas-liquid contact
    • 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
    • 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
    • B01D53/86—Catalytic processes
    • 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
    • B01D53/86—Catalytic processes
    • B01D53/8637—Simultaneously removing sulfur oxides and nitrogen oxides
    • 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
    • B01D53/92—Chemical or biological purification of waste gases of engine exhaust gases
    • B01D53/94—Chemical or biological purification of waste gases of engine exhaust gases by catalytic processes
    • 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
    • B01D53/92—Chemical or biological purification of waste gases of engine exhaust gases
    • B01D53/94—Chemical or biological purification of waste gases of engine exhaust gases by catalytic processes
    • B01D53/9404—Removing only nitrogen compounds
    • B01D53/9409—Nitrogen oxides
    • B01D53/9413—Processes characterised by a specific catalyst
    • B01D53/9418—Processes characterised by a specific catalyst for removing nitrogen oxides by selective catalytic reduction [SCR] using a reducing agent in a lean exhaust gas
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL-COMBUSTION ENGINES
    • F01N3/00—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
    • F01N3/08—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous
    • F01N3/10—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust
    • F01N3/18—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust characterised by methods of operation; Control
    • F01N3/20—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust characterised by methods of operation; Control specially adapted for catalytic conversion
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL-COMBUSTION ENGINES
    • F01N3/00—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
    • F01N3/08—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous
    • F01N3/10—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust
    • F01N3/18—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust characterised by methods of operation; Control
    • F01N3/20—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust characterised by methods of operation; Control specially adapted for catalytic conversion
    • F01N3/206—Adding periodically or continuously substances to exhaust gases for promoting purification, e.g. catalytic material in liquid form, NOx reducing agents
    • F01N3/2066—Selective catalytic reduction [SCR]
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2251/00—Reactants
    • B01D2251/10—Oxidants
    • B01D2251/104—Ozone
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2251/00—Reactants
    • B01D2251/20—Reductants

Definitions

  • the present invention relates to an exhaust gas treatment system including desulfurization and denitrification, and more particularly, to treat nitrogen oxides (NOx) and sulfur oxides (SOx) contained in exhaust gas discharged from large-scale combustion facilities such as thermal power plants. It relates to an exhaust gas treatment system including possible desulfurization and denitrification.
  • NOx nitrogen oxides
  • SOx sulfur oxides
  • Exhaust gas emitted from large-scale combustion facilities such as thermal power plants contains nitrogen oxides (NOx) and sulfur oxides (SOx), which are harmful substances, and a large exhaust gas treatment device is used to treat them to prevent air pollution.
  • NOx nitrogen oxides
  • SOx sulfur oxides
  • Ca-based reducing agents have been used in conventional desulfurization devices for power plants.
  • CaSO 4 which is a raw material for cement, is generated during the desulfurization process, and there is an economic effect by recycling.
  • an object of the present invention is to solve such conventional problems, and to achieve desulfurization and denitrification that can treat NOx and SOx contained in exhaust gas with high efficiency by spraying an aqueous solution containing Ca-based desulfurization agent and KI. It is to provide an exhaust gas treatment system that includes.
  • the cooling unit for lowering the temperature of the exhaust gas containing NOx and SOx; an ozone supply unit formed at a rear end of the cooling unit and supplying ozone (O 3 ) to oxidize NOx included in the cooled exhaust gas; and a scrubber formed at a rear end of the ozone supply unit and including a nozzle for injecting an aqueous solution containing Ca-based desulfurization agent and KI into the chamber.
  • the ozone supply unit supplies ozone at a concentration 1.7 times higher than that of NOx contained in the exhaust gas flowing from the cooling unit.
  • the scrubber further includes an aqueous solution storage tank for storing the aqueous solution, and the aqueous solution injected through the nozzle is recovered in the aqueous solution storage tank, and the Ca-based desulfurization agent is intermittently injected into the aqueous solution storage tank.
  • a pH sensor for measuring the pH concentration of the aqueous solution stored in the aqueous solution storage tank may be further included.
  • the pH of the aqueous solution becomes acidic, it is preferable to introduce the Ca-based desulfurization agent into the aqueous solution storage tank.
  • a desulfurization agent storage tank for storing the Ca-based desulfurization agent; and a control unit receiving a value measured by the pH sensor and controlling a timing of supplying the Ca-based desulfurization agent stored in the desulfurization agent storage tank to the aqueous solution storage tank based on the pH of the aqueous solution.
  • the Ca-based desulfurization agent may include CaCO 3 .
  • the Ca-based desulfurization agent is CaCO 3
  • the concentration of the KI is preferably 0.2M to 0.3M.
  • a selective catalytic reduction (SCR) device disposed at a front end of the cooling unit and reducing NOx included in exhaust gas may be further included.
  • the low-temperature process has the advantage of being able to reduce NOx along with SOx without high-temperature environmental conditions like existing SCRs.
  • FIG. 1 is a diagram schematically showing an exhaust gas treatment system including desulfurization and denitrification according to an embodiment of the present invention.
  • Figure 2 shows the results of experiments on the oxidation rate of NO according to the ratio of O 3 to NO.
  • FIG. 3 is a diagram showing the concept of material change in desulfurization and denitrification processes when an aqueous solution containing a Ca-based reducing agent and KI is used as a treatment liquid for desulfurization and denitrification according to the present invention.
  • FIG. 6 is an experiment result of NOx removal efficiency according to the concentration change of KI under the condition of intermittent addition of CaCO 3 .
  • FIG. 1 is a diagram schematically showing an exhaust gas treatment system including desulfurization and denitrification according to an embodiment of the present invention
  • FIG. 2 shows the result of an experiment on the oxidation rate of NO according to the ratio of O3 to NO.
  • An exhaust gas treatment system including desulfurization and denitrification may include a cooling unit 300 , an ozone supply unit 400 and a scrubber 100 .
  • a selective catalytic reduction (SCR) 200 may be further included.
  • the cooling unit 300 cools exhaust gas discharged from large-scale combustion facilities such as thermal power plants at the front end of the ozone supply unit 400 .
  • ozone (O 3 ) is supplied to the exhaust gas to react with non-aqueous NO to produce water-soluble NO 2 . Since ozone is decomposed at high temperatures and the reactivity with ozone is reduced, the cooling unit In step 300, the temperature of the exhaust gas can be lowered to a predetermined temperature or less.
  • a selective catalytic reduction device 200 may be disposed in front of the cooling unit 300 . Since NOx contained in the exhaust gas is reduced by the selective catalytic reduction device 200 and can be discharged in a high temperature state when discharged, there is a cooling unit on the pipe between the selective catalytic reduction device 200 and the ozone supply unit 400 ( 300) is preferably disposed.
  • the selective catalytic reduction device 200 since NOx reduced in the selective catalytic reduction device 200 is reduced together with SOx in the subsequent scrubber 100, the selective catalytic reduction device 200 does not necessarily need to be disposed. That is, the exhaust gas treatment system of the present invention may be configured to simultaneously reduce SOx and NOx in the scrubber 100 without the selective catalytic reduction device 200.
  • the cooling unit 300 may be configured to lower the temperature of the exhaust gas by heat exchange by passing cooling water on a pipe through which the exhaust gas flows. A portion of the cooling water used in the cooling unit 300 may be supplied to the aqueous solution storage tank 140 of the scrubber 100 to be described later through the cooling water pipe 310 .
  • the ozone supply unit 400 is formed in front of the inlet 112 through which the exhaust gas flows into the scrubber 100.
  • the ozone supply unit 400 supplies ozone to the exhaust gas flowing toward the scrubber 100 to react with the non-aqueous NO contained in the exhaust gas as shown in Scheme 1 to generate water-soluble NO 2 .
  • a sensor (not shown) may be disposed at the front end of the ozone supply unit 400 to measure the concentration of NO contained in the exhaust gas flowing toward the ozone supply unit 400, and the ozone supply unit 400 is It is preferable to input the value and accordingly supply the amount of ozone supplied to the exhaust gas at 1.7 times or more of the NO concentration.
  • the scrubber 100 is formed at the rear end of the ozone supply unit 400 and sprays an aqueous solution containing a Ca-based desulfurizer and KI to simultaneously reduce NOx and SOx contained in exhaust gas.
  • the scrubber 100 may include a chamber 110, an aqueous solution storage tank 140, a nozzle 120, and a desulfurization agent storage tank 160.
  • the chamber 110 provides a space in which the exhaust gas is processed, and an inlet 112 through which the exhaust gas flows is formed on the lower outer wall, and an outlet 114 through which NOx and SOx are reduced and finally treated exhaust gas is discharged at the upper side. ) can be formed.
  • the inlet 112 is formed on the lower side and the outlet 114 is formed on the upper side, the exhaust gas flowing into the chamber 110 flows from the lower side to the upper side within the chamber 110 .
  • the nozzle 120 is disposed inside the chamber 110 and sprays an aqueous solution for simultaneously reducing NOx and SOx.
  • a plurality of nozzles 120 are spaced apart in the horizontal direction inside the chamber 110 to spray the aqueous solution downward. Details of the aqueous solution will be described later.
  • a packing part 130 may be formed under the nozzle 120, and the packing part 130 is provided in a spherical shape and is stacked and arranged to contact each other to form a gap therebetween.
  • the packing part 130 can improve treatment efficiency by increasing the area and time for gas-liquid reaction between the exhaust gas flowing from the bottom to the top and the aqueous solution sprayed from top to bottom.
  • the nozzles 120 are formed in the upper and middle parts of the chamber 110, respectively, and the packing part 130 is formed under each nozzle 120 to form a two-stage wet scrubber 100 type. It can, but is not necessarily limited thereto.
  • An aqueous solution storage tank 140 for storing the aqueous solution may be formed at the lower end of the chamber 110 .
  • the aqueous solution stored in the aqueous solution storage tank 140 is supplied to the nozzle 120 by the pump 145 and sprayed into the chamber 110, and the injected aqueous solution is stored in the aqueous solution storage tank 140 together with the reactants.
  • aqueous solution which is a composition for simultaneously performing desulfurization and denitrification, will be described.
  • the composition may be composed of an aqueous solution containing a Ca-based desulfurization agent and potassium iodide (KI).
  • KI potassium iodide
  • FIG. 3 is a diagram showing the concept of material change in desulfurization and denitrification processes when an aqueous solution containing a Ca-based reducing agent and KI is used as a treatment liquid for desulfurization and denitrification according to the present invention.
  • the Ca-based desulfurization agent is a conventionally used desulfurization material containing Ca, and may be, for example, CaCO 3 or CaO.
  • CaCO 3 is used as a desulfurization agent.
  • reaction process of KI contained in the aqueous solution with NOx can be represented by Reaction Schemes 2 to 3.
  • I - is a catalyst, and the reaction proceeds by repeating the production from I - to I 2 and from I 2 to I - .
  • the pH can be kept constant at 7.5 by the acidification reaction Scheme 4 and the basification reaction Scheme 7.
  • the reaction with NOx proceeds as in Scheme 4, so the aqueous solution is acidified and the pH can be lowered as the reaction proceeds.
  • an aqueous solution containing a Ca-based desulfurization agent and potassium iodide (KI) as a catalyst is used, but a small amount of the Ca-based desulfurization agent is intermittently dispersed and injected.
  • Figure 4 shows the NOx removal efficiency when an aqueous solution containing a Ca-based reducing agent and KI is used as a treatment liquid for desulfurization and denitrification according to the present invention, but CaCO 3 1M is initially introduced once.
  • Fig. 2 the SOx removal efficiency, NOx removal efficiency, and concentration change of the aqueous solution are shown together when an aqueous solution containing Ca-based reducing agent and KI is used as a treatment solution for desulfurization and denitrification, but CaCO 3 0.02M is intermittently injected.
  • the residence time of the exhaust gas in the scrubber 100 was set to 2 seconds.
  • the concentration of NOx and SOx contained in the exhaust gas flowing into the scrubber 100, the liquid-to-liquid ratio of the aqueous solution injected from the nozzle 120 and the exhaust gas in the chamber 110 are similar to the actual conditions of use. This is the result of the experiment with the value shown in 1.
  • the scrubber 100 has a desulfurization agent storage tank 160 for storing Ca-based desulfurization agent and a pH sensor 170 for measuring the pH concentration of the aqueous solution stored in the aqueous solution storage tank 140 and a pH sensor 170 It may further include a control unit 180 that intermittently operates the pump 165 according to the value measured by the control unit 180 to supply a small amount of Ca-based desulfurization agent stored in the desulfurization agent storage tank 160 to the aqueous solution storage tank 140.
  • FIG. 6 is an experiment result of NOx removal efficiency according to the concentration change of KI under the condition of intermittent addition of CaCO 3 .
  • the KI concentration is preferably set to a value of 0.2M to 0.3M.

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Abstract

The present invention relates to an exhaust gas processing system which simultaneously performs desulfurization and denitrification, and the exhaust gas processing system which simultaneously performs desulfurization and denitrification, according to the present invention, comprises: a cooling part for lowering the temperature of an exhaust gas comprising NOx and SOx; an ozone supply part formed at the rear end of the cooling part, for supplying ozone (O3) to oxidize NOx included in the cooled exhaust gas; and a nozzle formed at the rear end of the ozone supply part, for spraying, in a chamber, an aqueous solution comprising a Ca-based desulfurization agent and KI.

Description

탈황 및 탈질을 포함하는 배기가스 처리 시스템Exhaust gas treatment system including desulfurization and denitrification

본 발명은 탈황 및 탈질을 포함하는 배기가스 처리 시스템에 관한 것으로서, 보다 상세하게는 화력 발전소와 같이 대규모 연소설비에서 배출되는 배기가스에 포함된 질소산화물(NOx)과 황산화물(SOx)을 처리할 수 있는 탈황 및 탈질을 포함하는 배기가스 처리 시스템에 관한 것이다.The present invention relates to an exhaust gas treatment system including desulfurization and denitrification, and more particularly, to treat nitrogen oxides (NOx) and sulfur oxides (SOx) contained in exhaust gas discharged from large-scale combustion facilities such as thermal power plants. It relates to an exhaust gas treatment system including possible desulfurization and denitrification.

화력 발전소와 같이 대규모 연소설비에서 방출되는 배기가스에는 유해물질인 질소산화물(NOx)과 황산화물(SOx)이 포함되어 있어서, 대기오염 방지를 위해 이를 처리하는 대형의 배기가스 처리장치가 사용된다. Exhaust gas emitted from large-scale combustion facilities such as thermal power plants contains nitrogen oxides (NOx) and sulfur oxides (SOx), which are harmful substances, and a large exhaust gas treatment device is used to treat them to prevent air pollution.

종래, NOx와 SOx를 동시에 저감시키기 위해 Na2S와 NaSO3와 같이 Na 계열의 환원제를 사용하는 것이 시도되었다. 하지만, 이 경우 H2S와 같은 2차 오염물질이 배출되고 약품사용량이 많기 때문에 폐수처리를 위한 수처리 비용이 많이 들어서, 발전소와 같이 대량의 배기가스를 배출하는 경우에 적용하기에는 한계가 있다. Conventionally, attempts have been made to use Na-based reducing agents such as Na 2 S and NaSO 3 to simultaneously reduce NOx and SOx. However, in this case, secondary pollutants such as H 2 S are discharged and the amount of chemicals used is high, so the water treatment cost for wastewater treatment is high, so there is a limit to application to a power plant that emits a large amount of exhaust gas.

또한, 종래 발전소용 탈황장치에 Ca 계열의 환원제가 사용되어왔다. Ca 계열의 환원제를 사용하는 경우 탈황과정에서 시멘트의 원료가 되는 CaSO4가 생성되어 리사이클링에 의한 경제적 효과가 있기 때문에, 본 발명에서는 Ca 계열의 환원제를 사용하며 탈황과 탈질 효율을 극대화할 수 있는 배기가스 처리 시스템을 제안하고자 한다. In addition, Ca-based reducing agents have been used in conventional desulfurization devices for power plants. In the case of using a Ca-based reducing agent, CaSO 4 , which is a raw material for cement, is generated during the desulfurization process, and there is an economic effect by recycling. We would like to propose a gas treatment system.

따라서, 본 발명의 목적은 이와 같은 종래의 문제점을 해결하기 위한 것으로서, Ca계열의 탈황제 및 KI를 포함하는 수용액을 분사하여 배기가스에 포함된 NOx와 SOx를 고효율로 처리할 수 있는 탈황 및 탈질을 포함하는 배기가스 처리 시스템을 제공함에 있다.Accordingly, an object of the present invention is to solve such conventional problems, and to achieve desulfurization and denitrification that can treat NOx and SOx contained in exhaust gas with high efficiency by spraying an aqueous solution containing Ca-based desulfurization agent and KI. It is to provide an exhaust gas treatment system that includes.

본 발명이 해결하고자 하는 과제들은 이상에서 언급한 과제들로 제한되지 않으며, 언급되지 않은 또 다른 과제들은 아래의 기재로부터 당업자에게 명확하게 이해될 수 있을 것이다.The problems to be solved by the present invention are not limited to the above-mentioned problems, and other problems not mentioned will be clearly understood by those skilled in the art from the following description.

상기 목적은, 본 발명에 따라, NOx 및 SOx를 포함하는 배기가스의 온도를 낮추는 냉각부; 상기 냉각부 후단에 형성되어 냉각된 배기가스에 포함된 NOx를 산화시키기 위해 오존(O3)을 공급하는 오존 공급부; 및 상기 오존 공급부 후단에 형성되어 챔버 내에 Ca계열의 탈황제 및 KI를 포함하는 수용액을 분사하는 노즐을 포함하는 스크러버를 포함하는 탈황 및 탈질을 동시에 수행하는 배기가스 처리 시스템에 의해 달성될 수 있다. The above object, according to the present invention, the cooling unit for lowering the temperature of the exhaust gas containing NOx and SOx; an ozone supply unit formed at a rear end of the cooling unit and supplying ozone (O 3 ) to oxidize NOx included in the cooled exhaust gas; and a scrubber formed at a rear end of the ozone supply unit and including a nozzle for injecting an aqueous solution containing Ca-based desulfurization agent and KI into the chamber.

여기서, 상기 오존 공급부는 냉각부로부터 유입되는 배기가스에 포함된 NOx의 농도 대비 1.7배 이상의 농도의 오존을 공급하는 것이 바람직하다. Here, it is preferable that the ozone supply unit supplies ozone at a concentration 1.7 times higher than that of NOx contained in the exhaust gas flowing from the cooling unit.

여기서, 상기 스크러버는 상기 수용액을 저장하는 수용액 저장조를 더 포함하고, 상기 노즐을 통해 분사된 수용액은 상기 수용액 저장조에 회수되는데, 상기 수용액 저장조에 상기 Ca계열의 탈황제를 간헐적으로 투입시키는 것이 바람직하다. Here, the scrubber further includes an aqueous solution storage tank for storing the aqueous solution, and the aqueous solution injected through the nozzle is recovered in the aqueous solution storage tank, and the Ca-based desulfurization agent is intermittently injected into the aqueous solution storage tank.

여기서, 상기 수용액 저장조에 저장된 수용액의 pH 농도를 측정하는 pH 센서를 더 포함할 수 있다. Here, a pH sensor for measuring the pH concentration of the aqueous solution stored in the aqueous solution storage tank may be further included.

여기서, 상기 수용액의 pH가 떨어져 산성이 될 때, 상기 수용액 저장조에 상기 Ca계열의 탈황제를 투입시키는 것이 바람직하다. Here, when the pH of the aqueous solution becomes acidic, it is preferable to introduce the Ca-based desulfurization agent into the aqueous solution storage tank.

여기서, 상기 수용액의 pH가 4 이하로 떨어질 때, 상기 수용액 저장조에 상기 Ca계열의 탈황제를 투입시키는 것이 바람직하다. Here, when the pH of the aqueous solution drops below 4, it is preferable to introduce the Ca-based desulfurization agent into the aqueous solution storage tank.

여기서, 상기 Ca계열의 탈황제를 저장하는 탈황제 저장조; 및 상기 pH 센서에서 측정된 값을 수신하여 상기 수용액의 pH를 기초로 상기 탈황제 저장조에 저장된 Ca 계열의 탈황제를 상기 수용액 저장탱크로 공급하는 시기를 제어하는 제어부를 포함할 수 있다. Here, a desulfurization agent storage tank for storing the Ca-based desulfurization agent; and a control unit receiving a value measured by the pH sensor and controlling a timing of supplying the Ca-based desulfurization agent stored in the desulfurization agent storage tank to the aqueous solution storage tank based on the pH of the aqueous solution.

여기서, 상기 Ca 계열의 탈황제는 CaCO3를 포함할 수 있다. Here, the Ca-based desulfurization agent may include CaCO 3 .

여기서, 상기 Ca 계열의 탈황제는 CaCO3이고, 상기 KI의 농도는 0.2M 내지 0.3M인 것이 바람직하다. Here, the Ca-based desulfurization agent is CaCO 3 , and the concentration of the KI is preferably 0.2M to 0.3M.

여기서, 상기 냉각부의 전단부에 배치되며 배기가스에 포함된 NOx를 저감하는 선택적 촉매환원장치(Selective Catalytic Reduction: SCR)를 더 포함할 수 있다. Here, a selective catalytic reduction (SCR) device disposed at a front end of the cooling unit and reducing NOx included in exhaust gas may be further included.

상기한 바와 같은 본 발명의 탈황 및 탈질을 포함하는 배기가스 처리 시스템에 따르면 기존 발전소에 사용되는 Ca계열의 환원제를 그대로 사용하여 시멘트 원료를 재사용하여 경제적이며 고효율로 NOx와 SOx를 동시에 저감시킬 수 있다는 장점이 있다. According to the exhaust gas treatment system including desulfurization and denitrification of the present invention as described above, it is economical and highly efficient to reduce NOx and SOx at the same time by reusing cement raw materials using Ca-based reducing agents used in existing power plants. There are advantages.

또한, 저온의 공정으로 기존 SCR와 같이 고온 환경 조건 없이 SOx와 함께 NOx도 저감시킬 수 있다는 장점도 있다. In addition, the low-temperature process has the advantage of being able to reduce NOx along with SOx without high-temperature environmental conditions like existing SCRs.

또한, 저농도의 NOx도 고효율로 저감시킬 수 있다는 장점도 있다. In addition, there is also an advantage that low concentration NOx can be reduced with high efficiency.

도 1은 본 발명의 일 실시예에 따른 탈황 및 탈질을 포함하는 배기가스 처리 시스템을 개략적으로 도시하는 도면이다. 1 is a diagram schematically showing an exhaust gas treatment system including desulfurization and denitrification according to an embodiment of the present invention.

도 2는 NO 대비 O3의 비율에 따른 NO의 산화율을 실험한 결과를 도시한다. Figure 2 shows the results of experiments on the oxidation rate of NO according to the ratio of O 3 to NO.

도 3은 본 발명에 따라 Ca 계열의 환원제 및 KI를 포함하는 수용액을 탈황탈질의 처리액으로 사용하는 경우 탈황 및 탈질 과정에서의 물질 변화 개념을 도시하는 도면이다. FIG. 3 is a diagram showing the concept of material change in desulfurization and denitrification processes when an aqueous solution containing a Ca-based reducing agent and KI is used as a treatment liquid for desulfurization and denitrification according to the present invention.

도 4는 본 발명에 따라 Ca 계열의 환원제 및 KI를 포함하는 수용액을 탈황탈질의 처리액으로 사용하되 CaCO3 1M을 초기에 1회 투입한 경우의 NOx 제거 효율을 도시한다. 4 shows the NOx removal efficiency when an aqueous solution containing a Ca-based reducing agent and KI is used as a treatment solution for desulfurization and denitrification according to the present invention, but CaCO 3 1M is initially introduced once.

도 5는 본 발명에 따라 Ca 계열의 환원제 및 KI를 포함하는 수용액을 탈황탈질의 처리액으로 사용하되 CaCO3 0.02M을 간헐적으로 투입한 경우의 SOx 제거 효율, NOx 제거 효율 및 수용액의 농도 변화를 함께 도시한다.5 shows the SOx removal efficiency, NOx removal efficiency, and concentration change of the aqueous solution when an aqueous solution containing a Ca-based reducing agent and KI is used as a treatment solution for desulfurization and denitrification according to the present invention, but CaCO 3 0.02M is intermittently injected. show together

도 6은 CaCO3의 간헐적 투입 조건에서 KI의 농도 변화에 따른 NOx 제거 효율을 실험한 결과이다.FIG. 6 is an experiment result of NOx removal efficiency according to the concentration change of KI under the condition of intermittent addition of CaCO 3 .

실시예들의 구체적인 사항들은 상세한 설명 및 도면들에 포함되어 있다.The specific details of the embodiments are included in the detailed description and drawings.

본 발명의 이점 및 특징, 그리고 그것들을 달성하는 방법은 첨부되는 도면과 함께 상세하게 후술되어 있는 실시예들을 참조하면 명확해질 것이다. 그러나 본 발명은 이하에서 개시되는 실시예들에 한정되는 것이 아니라 서로 다른 다양한 형태로 구현될 수 있으며, 단지 본 실시예들은 본 발명의 개시가 완전하도록 하고, 본 발명이 속하는 기술분야에서 통상의 지식을 가진 자에게 발명의 범주를 완전하게 알려주기 위해 제공되는 것이며, 본 발명은 청구항의 범주에 의해 정의될 뿐이다. 명세서 전체에 걸쳐 동일 참조 부호는 동일 구성 요소를 지칭한다 Advantages and features of the present invention, and methods of achieving them, will become clear with reference to the embodiments described below in detail in conjunction with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below and may be implemented in various different forms, only the present embodiments make the disclosure of the present invention complete, and common knowledge in the art to which the present invention belongs. It is provided to completely inform the person who has the scope of the invention, and the present invention is only defined by the scope of the claims. Like reference numbers designate like elements throughout the specification.

이하, 본 발명의 실시예들에 의하여 탈황 및 탈질을 포함하는 배기가스 처리 시스템을 설명하기 위한 도면들을 참고하여 본 발명에 대해 설명하도록 한다.Hereinafter, the present invention will be described with reference to drawings for explaining an exhaust gas treatment system including desulfurization and denitrification according to embodiments of the present invention.

도 1은 본 발명의 일 실시예에 따른 탈황 및 탈질을 포함하는 배기가스 처리 시스템을 개략적으로 도시하는 도면이고, 도 2는 NO 대비 O3의 비율에 따른 NO의 산화율을 실험한 결과를 도시한다.FIG. 1 is a diagram schematically showing an exhaust gas treatment system including desulfurization and denitrification according to an embodiment of the present invention, and FIG. 2 shows the result of an experiment on the oxidation rate of NO according to the ratio of O3 to NO.

본 발명의 일 실시예에 따른 탈황 및 탈질을 포함하는 배기가스 처리 시스템은 냉각부(300), 오존 공급부(400) 및 스크러버(100)를 포함하여 구성될 수 있다. 또한, 선택적 촉매환원장치(Selective Catalytic Reduction: SCR)(200)를 더 포함할 수 있다.An exhaust gas treatment system including desulfurization and denitrification according to an embodiment of the present invention may include a cooling unit 300 , an ozone supply unit 400 and a scrubber 100 . In addition, a selective catalytic reduction (SCR) 200 may be further included.

냉각부(300)는 오존 공급부(400)의 전단에서 화력 발전소 등의 대형 연소설비에서 배출되는 배기가스를 냉각시킨다. The cooling unit 300 cools exhaust gas discharged from large-scale combustion facilities such as thermal power plants at the front end of the ozone supply unit 400 .

스크러버(100)의 전단에는 배기가스에 오존(O3)을 공급하여 비수용성의 NO와 반응시켜 수용성의 NO2를 생성시키는데, 고온에서는 오존이 분해되어 오존에 의한 반응성이 떨어지기 때문에, 냉각부(300)에 의해 배기가스의 온도를 소정의 온도 이하로 낮출 수가 있다. At the front end of the scrubber 100, ozone (O 3 ) is supplied to the exhaust gas to react with non-aqueous NO to produce water-soluble NO 2 . Since ozone is decomposed at high temperatures and the reactivity with ozone is reduced, the cooling unit In step 300, the temperature of the exhaust gas can be lowered to a predetermined temperature or less.

냉각부(300)의 전단에는 선택적 촉매환원장치(200)가 배치될 수 있다. 선택적 촉매환원장치(200)에 의해 배기가스에 포함된 NOx가 저감되어 배출될 때 고온의 상태로 배출될 수 있으므로, 선택적 촉매환원장치(200)와 오존 공급부(400) 사이의 배관 상에는 냉각부(300)가 배치되는 것이 바람직하다. A selective catalytic reduction device 200 may be disposed in front of the cooling unit 300 . Since NOx contained in the exhaust gas is reduced by the selective catalytic reduction device 200 and can be discharged in a high temperature state when discharged, there is a cooling unit on the pipe between the selective catalytic reduction device 200 and the ozone supply unit 400 ( 300) is preferably disposed.

후술하는 바와 같이 상기 선택적 촉매환원장치(200)에서 저감된 NOx는 후단의 스크러버(100)에서 SOx와 함께 다시 저감되므로, 선택적 촉매환원장치(200)는 반드시 배치될 필요는 없다. 즉, 본 발명의 배기가스 처리 시스템은 선택적 촉매환원장치(200) 없이 스크러버(100)에서 SOx와 NOx를 동시에 저감시키도록 구성될 수도 있다. As will be described later, since NOx reduced in the selective catalytic reduction device 200 is reduced together with SOx in the subsequent scrubber 100, the selective catalytic reduction device 200 does not necessarily need to be disposed. That is, the exhaust gas treatment system of the present invention may be configured to simultaneously reduce SOx and NOx in the scrubber 100 without the selective catalytic reduction device 200.

본 실시예에서 냉각부(300)는 배기가스가 유동하는 배관 상에 냉각수를 통과시켜 열교환에 의해 배기가스의 온도를 낮추도록 구성될 수 있다. 냉각부(300)에 사용되는 냉각수의 일부는 냉각수 배관(310)을 통해 후술하는 스크러버(100)의 수용액 저장조(140)에 공급될 수 있다. In this embodiment, the cooling unit 300 may be configured to lower the temperature of the exhaust gas by heat exchange by passing cooling water on a pipe through which the exhaust gas flows. A portion of the cooling water used in the cooling unit 300 may be supplied to the aqueous solution storage tank 140 of the scrubber 100 to be described later through the cooling water pipe 310 .

오존 공급부(400)는 스크러버(100) 내부로 배기가스가 유입되는 유입구(112) 전단 형성된다. 오존 공급부(400)는 스크러버(100)를 향하여 유동하는 배기가스에 오존을 공급하여 반응식 1과 같이 배기가스에 포함된 비수용성의 NO와 반응시켜 수용성의 NO2가 생성되도록 한다. The ozone supply unit 400 is formed in front of the inlet 112 through which the exhaust gas flows into the scrubber 100. The ozone supply unit 400 supplies ozone to the exhaust gas flowing toward the scrubber 100 to react with the non-aqueous NO contained in the exhaust gas as shown in Scheme 1 to generate water-soluble NO 2 .

NO+O3 -> NO2+O2 <반응식 1>NO+O 3 -> NO 2 +O 2 <Scheme 1>

도 2에서는 NO 대비 오존의 비율에 따른 NO의 산화율을 실험한 결과를 보여준다. 실험 결과에 따르면 NO의 (몰)농도 대비 오존의 (몰)농도가 1.7배가될 때 산화율이 대략 77%로 포화됨을 확인할 수 있다. 2 shows the results of experiments on the oxidation rate of NO according to the ratio of ozone to NO. According to the experimental results, it can be confirmed that the oxidation rate is saturated at approximately 77% when the (molar) concentration of ozone is 1.7 times greater than the (molar) concentration of NO.

따라서, 오존 공급부(400)의 전단에는 오존 공급부(400)를 향하여 유동하는 배기가스에 포함된 NO의 농도를 측정하는 센서(미도시)가 배치될 수 있고, 오존 공급부(400)는 상기 센서의 값을 입력 받아 이에 따라 배기가스에 공급되는 오존의 양을 NO 농도의 1.7배 이상으로 공급시키는 것이 바람직하다. Therefore, a sensor (not shown) may be disposed at the front end of the ozone supply unit 400 to measure the concentration of NO contained in the exhaust gas flowing toward the ozone supply unit 400, and the ozone supply unit 400 is It is preferable to input the value and accordingly supply the amount of ozone supplied to the exhaust gas at 1.7 times or more of the NO concentration.

스크러버(100)는 오존 공급부(400) 후단에 형성되어 Ca계열의 탈황제 및 KI를 포함하는 수용액을 분사시켜 배기가스에 포함된 NOx와 SOx를 동시에 저감시킨다. The scrubber 100 is formed at the rear end of the ozone supply unit 400 and sprays an aqueous solution containing a Ca-based desulfurizer and KI to simultaneously reduce NOx and SOx contained in exhaust gas.

스크러버(100)는 챔버(110), 수용액 저장조(140), 노즐(120), 탈황제 저장조(160)를 포함하여 구성될 수 있다. The scrubber 100 may include a chamber 110, an aqueous solution storage tank 140, a nozzle 120, and a desulfurization agent storage tank 160.

챔버(110)는 배기가스가 처리되는 공간을 제공하며, 하측 외벽에는 배기가스가 유입되는 유입구(112)가 형성되며, 상측에는 NOx와 SOx가 저감되어 최종 처리된 배기가스가 배출되는 배출구(114)가 형성될 수 있다. The chamber 110 provides a space in which the exhaust gas is processed, and an inlet 112 through which the exhaust gas flows is formed on the lower outer wall, and an outlet 114 through which NOx and SOx are reduced and finally treated exhaust gas is discharged at the upper side. ) can be formed.

하측에 유입구(112)가 형성되고 상측에 배출구(114)가 형성되므로 챔버(110) 내부로 유입되는 배기가스는 챔버(110) 내 하측에서 상측 방향으로 유동한다. Since the inlet 112 is formed on the lower side and the outlet 114 is formed on the upper side, the exhaust gas flowing into the chamber 110 flows from the lower side to the upper side within the chamber 110 .

노즐(120)은 챔버(110) 내부에 배치되어 NOx 및 SOx를 동시에 저감시키기 위한 수용액을 분사한다. 노즐(120)은 챔버(110) 내부에 수평 방향으로 복수 개 이격 배치되어 아래를 향하여 수용액을 분사할 수 있다. 상기 수용액에 관한 상세 내용은 후술하기로 한다. The nozzle 120 is disposed inside the chamber 110 and sprays an aqueous solution for simultaneously reducing NOx and SOx. A plurality of nozzles 120 are spaced apart in the horizontal direction inside the chamber 110 to spray the aqueous solution downward. Details of the aqueous solution will be described later.

노즐(120) 아래에는 패킹부(130)가 형성될 수 있는데, 패킹부(130)는 구 형태 등으로 마련되어 서로 맞닿아 적층 배열됨으로써 사이에 공극을 형성한다. 상기 패킹부(130)는 아래에서 위로 유동하는 배기가스와 위에서 아래로 분사되는 수용액과의 기액 반응을 위한 면적 및 시간을 늘려 처리 효율을 향상시킬 수 있다. A packing part 130 may be formed under the nozzle 120, and the packing part 130 is provided in a spherical shape and is stacked and arranged to contact each other to form a gap therebetween. The packing part 130 can improve treatment efficiency by increasing the area and time for gas-liquid reaction between the exhaust gas flowing from the bottom to the top and the aqueous solution sprayed from top to bottom.

본 발명에서 노즐(120)은 챔버(110)의 상단부 및 중간부에 각각 형성되고, 각 노즐(120) 아래에는 패킹부(130)가 형성되는 2단 구조의 습식 스크러버(100) 타입으로 형성될 수 있으나, 반드시 이에 한정되는 것은 아니다. In the present invention, the nozzles 120 are formed in the upper and middle parts of the chamber 110, respectively, and the packing part 130 is formed under each nozzle 120 to form a two-stage wet scrubber 100 type. It can, but is not necessarily limited thereto.

챔버(110) 하단부에는 상기 수용액이 저장되는 수용액 저장조(140)가 형성될 수 있다. 수용액 저장조(140)에 저장된 수용액은 펌프(145)에 의해 노즐(120)로 공급되어 챔버(110) 내부로 분사되고, 분사된 수용액은 반응물과 함께 다시 수용액 저장조(140)에 저장될 수 있다. An aqueous solution storage tank 140 for storing the aqueous solution may be formed at the lower end of the chamber 110 . The aqueous solution stored in the aqueous solution storage tank 140 is supplied to the nozzle 120 by the pump 145 and sprayed into the chamber 110, and the injected aqueous solution is stored in the aqueous solution storage tank 140 together with the reactants.

이하, 탈황 및 탈질을 동시에 수행하기 위한 조성물인 상기 수용액에 대하여 설명하기로 한다. Hereinafter, the aqueous solution, which is a composition for simultaneously performing desulfurization and denitrification, will be described.

상기 조성물은 Ca 계열의 탈황제 및 요오드화 칼륨(KI)이 포함된 수용액으로 구성될 수 있다. The composition may be composed of an aqueous solution containing a Ca-based desulfurization agent and potassium iodide (KI).

참고로, 도 3은 본 발명에 따라 Ca 계열의 환원제 및 KI를 포함하는 수용액을 탈황탈질의 처리액으로 사용하는 경우 탈황 및 탈질 과정에서의 물질 변화 개념을 도시하는 도면이다. For reference, FIG. 3 is a diagram showing the concept of material change in desulfurization and denitrification processes when an aqueous solution containing a Ca-based reducing agent and KI is used as a treatment liquid for desulfurization and denitrification according to the present invention.

Ca 계열의 탈황제는 Ca를 포함하는 종래 사용되어 왔던 탈황 물질로서, 예를 들어 CaCO3, CaO일 수 있다. 이하, 설명에서는 탈황제로 CaCO3가 사용되는 경우를 예를 들어 설명하기로 한다. The Ca-based desulfurization agent is a conventionally used desulfurization material containing Ca, and may be, for example, CaCO 3 or CaO. Hereinafter, a case in which CaCO 3 is used as a desulfurization agent will be described as an example.

상기 수용액에 포함되는 KI에 의한 NOx와의 반응 과정은 반응식 2 내지 반응식 3으로 나타낼 수 있다. The reaction process of KI contained in the aqueous solution with NOx can be represented by Reaction Schemes 2 to 3.

2NO2+2KI -> 2KNO2+I2 <반응식 2>2NO 2 +2KI -> 2KNO 2 +I 2 <Scheme 2>

I2+SO2+2H2O -> H2SO4+2HI <반응식 3>I 2 +SO 2 +2H 2 O -> H 2 SO 4 +2HI <Scheme 3>

반응식 2에서 KI가 물에 녹아 I-를 생성하게 되고, I-가 촉매로 작용하여 NO2가스가 물에 녹아 NO2 - 및 I2를 생성하게 된다. 또한, 반응식 3에서 배기가스에 포함된 SO2는 물에 녹아 SO3 2-를 생성하게 되고, SO3 2-는 반응식 2에서 생성된 I2 와 반응하여 SO4 2- 와 I-을 생성하게 된다(반응식 3). In Scheme 2, KI dissolves in water to generate I − , and I − acts as a catalyst and NO 2 gas dissolves in water to produce NO 2 − and I 2 . In addition, in Reaction Equation 3, SO 2 contained in exhaust gas dissolves in water to produce SO 3 2- , and SO 3 2- reacts with I 2 generated in Reaction Equation 2 to produce SO 4 2- and I - . (Scheme 3).

따라서, 상기 반응식 2 및 반응식 3에서 I-은 촉매로서 I- 에서 I2로 I2에서 I-로 생성을 순환 반복하여 반응을 진행하게 된다. Therefore, in Reaction Scheme 2 and Reaction Scheme 3, I - is a catalyst, and the reaction proceeds by repeating the production from I - to I 2 and from I 2 to I - .

다음, CaCO3에 의한 탈황 과정은 다음의 반응식 4 내지 7로 나타낼 수 있다. Next, the desulfurization process by CaCO 3 can be represented by the following Schemes 4 to 7.

SO2(g)+H2O -> 2H++SO3 2- <반응식 4>SO 2 (g)+H 2 O -> 2H + +SO 3 2- <Scheme 4>

CaCO3 -> Ca2 + + CO3 2- <반응식 5>CaCO 3 -> Ca 2 + + CO 3 2- <Scheme 5>

Ca2 ++SO3 2- -> CaSO3 <반응식 6>Ca 2 + +SO 3 2- -> CaSO 3 <Scheme 6>

CO3 2- +2H+ -> CO2+H2O <반응식 7>CO 3 2- +2H + -> CO 2 +H 2 O <Scheme 7>

촉매 반응을 위한 KI 성분이 없이 CaCO3 수용액에 의해 탈황 반응만 일어난다면 산성화 반응인 반응식 4와 염기화 반응인 반응식 7에 의해 pH가 7.5로 일정하게 유지될 수 있다. 하지만, 본 발명에서 촉매로 KI가 투입되므로, NOx와의 반응 과정(반응식 3의 중간 반응 과정)에서도 반응식 4와 같은 반응이 진행되므로 반응이 진행됨에 따라서 수용액은 산성화되어 pH가 낮아질 수가 있다. If only the desulfurization reaction occurs by the CaCO 3 aqueous solution without the KI component for the catalytic reaction, the pH can be kept constant at 7.5 by the acidification reaction Scheme 4 and the basification reaction Scheme 7. However, since KI is introduced as a catalyst in the present invention, the reaction with NOx (intermediate reaction process of Scheme 3) proceeds as in Scheme 4, so the aqueous solution is acidified and the pH can be lowered as the reaction proceeds.

이때, NOx 처리 반응인 반응식 2 내지 3에 필요한 SO3 2-가 SOx 처리 반응 중 반응식 6에서 Ca2 +에 의해 소모되므로, CaCO3가 과량일 때 NOx의 저감 효율이 떨어질 수가 있다. At this time, since SO 3 2- required in Reaction Schemes 2 to 3, which are NOx treatment reactions, is consumed by Ca 2+ in Reaction Scheme 6 during the SOx treatment reaction, NOx reduction efficiency may decrease when CaCO 3 is excessive.

이에, 본 발명에서는 탈황 및 탈질을 동시에 수행하기 위한 조성물로 Ca 계열의 탈황제 및 촉매로 요오드화 칼륨(KI)이 포함된 수용액을 사용하되, Ca 계열의 탈황제는 간헐적으로 소량 분산 투입하는 것이 바람직하다. Therefore, in the present invention, as a composition for simultaneously performing desulfurization and denitrification, an aqueous solution containing a Ca-based desulfurization agent and potassium iodide (KI) as a catalyst is used, but a small amount of the Ca-based desulfurization agent is intermittently dispersed and injected.

도 4는 본 발명에 따라 Ca 계열의 환원제 및 KI를 포함하는 수용액을 탈황탈질의 처리액으로 사용하되 CaCO3 1M을 초기에 1회 투입한 경우의 NOx 제거 효율을 도시하고, 도 5는 본 발명에 따라 Ca 계열의 환원제 및 KI를 포함하는 수용액을 탈황탈질의 처리액으로 사용하되 CaCO3 0.02M을 간헐적으로 투입한 경우의 SOx 제거 효율, NOx 제거 효율 및 수용액의 농도 변화를 함께 도시한다. Figure 4 shows the NOx removal efficiency when an aqueous solution containing a Ca-based reducing agent and KI is used as a treatment liquid for desulfurization and denitrification according to the present invention, but CaCO 3 1M is initially introduced once. According to Fig. 2, the SOx removal efficiency, NOx removal efficiency, and concentration change of the aqueous solution are shown together when an aqueous solution containing Ca-based reducing agent and KI is used as a treatment solution for desulfurization and denitrification, but CaCO 3 0.02M is intermittently injected.

참고로, 도 4 및 도 5의 실험에서 실제 탈황 조건과 유사하게 스크러버(100) 내에 배기가스의 체류시간은 2초로 설정하였다. 또한, 스크러버(100) 내에 유입되는 배기가스에 포함된 NOx의 농도 및 SOx의 농도, 노즐(120)로부터 분사되는 수용액의 챔버(110) 내 배기가스와의 액기비는 실제 사용 조건과 유사하게 도 1에 표시된 값으로 실험한 결과이다. For reference, similar to the actual desulfurization conditions in the experiments of FIGS. 4 and 5, the residence time of the exhaust gas in the scrubber 100 was set to 2 seconds. In addition, the concentration of NOx and SOx contained in the exhaust gas flowing into the scrubber 100, the liquid-to-liquid ratio of the aqueous solution injected from the nozzle 120 and the exhaust gas in the chamber 110 are similar to the actual conditions of use. This is the result of the experiment with the value shown in 1.

도 4에 도시되어 있는 것과 같이 CaCO3를 초기에 과량으로 투입한 경우에는 NO2 제거 효율이 평균 54%이고, 도 5에 도시되어 있는 것과 같이 CaCO3를 소량으로 간헐적으로 투입한 경우에는 NO2 제거 효율이 평균 74%로 상대적으로 높다는 것을 확인할 수 있다. As shown in FIG. 4, when an excessive amount of CaCO 3 was initially introduced, the NO 2 removal efficiency was 54% on average, and as shown in FIG. 5, when a small amount of CaCO 3 was intermittently introduced, NO 2 It can be seen that the removal efficiency is relatively high with an average of 74%.

이때, 도 5에서 pH 가 4 이하일 때 SO2 제거 효율이 떨어짐을 확인할 수 있고, 수용액의 pH 4가 4 이하일 때 CaCO3를 소량으로 투입하면 pH가 상승을 하고 SO2 제거 효율이 다시 상승함을 확인할 수 있다. 따라서, 탈황 탈질을 위한 상기 수용액에 CaCO3를 소량으로 투입하되 수용액의 pH가 산성으로 떨어질 때, 보다 바람직하게는 수용액의 pH가 4이하로 떨어질 때마다 간헐적으로 투입하는 것이 바람직하다. CaCO3를 투입시켜 pH값이 회복되면 SO2 제거 효율이 다시 회복됨을 확인할 수 있다. At this time, it can be seen in FIG. 5 that the SO 2 removal efficiency decreases when the pH is 4 or less, and when the pH 4 of the aqueous solution is 4 or less, when a small amount of CaCO 3 is added, the pH rises and the SO 2 removal efficiency rises again. You can check. Therefore, it is preferable to add a small amount of CaCO 3 to the aqueous solution for desulfurization and denitrification, but intermittently add CaCO 3 whenever the pH of the aqueous solution drops to acidic, more preferably whenever the pH of the aqueous solution drops below 4. It can be seen that when the pH value is restored by adding CaCO 3 , the SO 2 removal efficiency is restored again.

상기와 같은 특징에 따라서 상기 스크러버(100)는 Ca 계열의 탈황제를 저장하는 탈황제 저장조(160) 및 수용액 저장조(140)에 저장된 수용액의 pH 농도를 측정하는 pH 센서(170) 및 pH 센서(170)에 의해 측정된 값에 따라서 펌프(165)를 간헐적으로 동작시켜 탈황제 저장조(160)에 저장된 Ca 계열의 탈황제를 수용액 저장조(140)로 소량 공급하도록 제어하는 제어부(180)를 더 포함할 수 있다. According to the above characteristics, the scrubber 100 has a desulfurization agent storage tank 160 for storing Ca-based desulfurization agent and a pH sensor 170 for measuring the pH concentration of the aqueous solution stored in the aqueous solution storage tank 140 and a pH sensor 170 It may further include a control unit 180 that intermittently operates the pump 165 according to the value measured by the control unit 180 to supply a small amount of Ca-based desulfurization agent stored in the desulfurization agent storage tank 160 to the aqueous solution storage tank 140.

CaCO3를 초기에 과량으로 투입한 경우보다 수용액의 농도 변화에 따라 CaCO3를 소량으로 간헐적으로 투입한 경우에 NO2 제거 효율이 높다는 것을 상기 실험 결과를 통해 확인할 수 있고, CaCO3이 간헐적 투입 조건에서 다른 조건 변화에 따른 NO2 제거 효율을 실험한 결과를 도 6에 도시한다. It can be confirmed through the above experimental results that NO 2 removal efficiency is higher when CaCO 3 is added intermittently in a small amount according to the concentration change of the aqueous solution than when CaCO 3 is initially added in excess, and CaCO 3 is added intermittently Figure 6 shows the results of testing the NO 2 removal efficiency under different conditions.

도 6은 CaCO3의 간헐적 투입 조건에서 KI의 농도 변화에 따른 NOx 제거 효율을 실험한 결과이다.FIG. 6 is an experiment result of NOx removal efficiency according to the concentration change of KI under the condition of intermittent addition of CaCO 3 .

도 6은 배기가스에 포함된 NO의 농도를 20ppm으로 고정시킨 상태에서 CaCO3를 소량으로 간헐적 투입시키되 수용액 내 KI의 농도를 바꾸어가며 NOx 제거 효율을 실험한 결과이다. KI의 농도가 0.2M이 될 때까지는 대체로 KI의 농도가 증가함에 따라 NOx 제거 효율이 선형적으로 증가함을 확인할 수 있다. 또한, KI의 농도가 0.2M 내지 0.3M에서는 선형적 증가 추세가 꺾이고, 0.3M 이상의 값에서는 증가 추세가 거의 없는 것을 확인할 수 있다. 따라서, KI의 소비량 및 NOx 제거 효율을 고려하였을 때, KI의 농도는 0.2M 내지 0.3M의 값을 가지도록 하는 것이 바람직하다. 6 is a result of testing the NOx removal efficiency while changing the concentration of KI in an aqueous solution while intermittently introducing a small amount of CaCO 3 in a state in which the concentration of NO included in the exhaust gas is fixed at 20 ppm. It can be seen that the NOx removal efficiency increases linearly as the concentration of KI increases until the concentration of KI reaches 0.2 M. In addition, it can be seen that the linear increase trend is broken when the concentration of KI is 0.2M to 0.3M, and there is almost no increase trend at a value of 0.3M or more. Therefore, considering the KI consumption and NOx removal efficiency, the KI concentration is preferably set to a value of 0.2M to 0.3M.

본 발명의 권리범위는 상술한 실시예에 한정되는 것이 아니라 첨부된 특허청구범위 내에서 다양한 형태의 실시예로 구현될 수 있다. 특허청구범위에서 청구하는 본 발명의 요지를 벗어남이 없이 당해 발명이 속하는 기술 분야에서 통상의 지식을 가진 자라면 누구든지 변형 가능한 다양한 범위까지 본 발명의 청구범위 기재의 범위 내에 있는 것으로 본다.The scope of the present invention is not limited to the above-described embodiments, but may be implemented in various forms of embodiments within the scope of the appended claims. Anyone with ordinary knowledge in the art to which the invention pertains without departing from the subject matter of the invention claimed in the claims is considered to be within the scope of the claims of the present invention to various extents that can be modified.

100: 스크러버100: scrubber

110: 챔버110: chamber

112: 유입구112: inlet

114: 배출구114: outlet

120: 노즐120: nozzle

130: 패킹부130: packing part

140: 수용액 저장조140: aqueous solution reservoir

145: 펌프145: pump

160: 탈황제 저장조160: desulfurization agent storage tank

165: 펌프165: pump

170: pH 센서170: pH sensor

180: 제어부180: control unit

200: 선택적 촉매환원장치200: selective catalytic reduction device

300: 냉각부300: cooling unit

310: 냉각수 배관310: cooling water piping

400: 오존 공급부400: ozone supply unit

Claims (10)

NOx 및 SOx를 포함하는 배기가스의 온도를 낮추는 냉각부;A cooling unit that lowers the temperature of exhaust gas containing NOx and SOx; 상기 냉각부 후단에 형성되어 냉각된 배기가스에 포함된 NOx를 산화시키기 위해 오존(O3)을 공급하는 오존 공급부; 및an ozone supply unit formed at a rear end of the cooling unit and supplying ozone (O 3 ) to oxidize NOx included in the cooled exhaust gas; and 상기 오존 공급부 후단에 형성되어 챔버 내에 Ca계열의 탈황제 및 KI를 포함하는 수용액을 분사하는 노즐을 포함하는 스크러버를 포함하는 탈황 및 탈질을 동시에 수행하는 배기가스 처리 시스템.An exhaust gas treatment system that simultaneously performs desulfurization and denitrification including a scrubber including a nozzle formed at a rear end of the ozone supply unit and spraying an aqueous solution containing Ca-based desulfurization agent and KI into the chamber. 제 1 항에 있어서,According to claim 1, 상기 오존 공급부는 냉각부로부터 유입되는 배기가스에 포함된 NOx의 농도 대비 1.7배 이상의 농도의 오존을 공급하는 탈황 및 탈질을 동시에 수행하는 배기가스 처리 시스템.The ozone supply unit simultaneously performs desulfurization and denitrification to supply ozone at a concentration of 1.7 times or more compared to the concentration of NOx contained in the exhaust gas flowing from the cooling unit. 제 1 항에 있어서,According to claim 1, 상기 스크러버는 상기 수용액을 저장하는 수용액 저장조를 더 포함하고, The scrubber further comprises an aqueous solution storage tank for storing the aqueous solution, 상기 노즐을 통해 분사된 수용액은 상기 수용액 저장조에 회수되는데, 상기 수용액 저장조에 상기 Ca계열의 탈황제를 간헐적으로 투입시키는 탈황 및 탈질을 동시에 수행하는 배기가스 처리 시스템.The aqueous solution sprayed through the nozzle is recovered in the aqueous solution storage tank, and the exhaust gas treatment system simultaneously performs desulfurization and denitrification by intermittently injecting the Ca-based desulfurization agent into the aqueous solution storage tank. 제 3 항에 있어서,According to claim 3, 상기 수용액 저장조에 저장된 수용액의 pH 농도를 측정하는 pH 센서를 더 포함하는 탈황 및 탈질을 동시에 수행하는 배기가스 처리 시스템.An exhaust gas treatment system that simultaneously performs desulfurization and denitrification further comprising a pH sensor for measuring the pH concentration of the aqueous solution stored in the aqueous solution storage tank. 제 4 항에 있어서,According to claim 4, 상기 수용액의 pH가 떨어져 산성이 될 때, 상기 수용액 저장조에 상기 Ca계열의 탈황제를 투입시키는 탈황 및 탈질을 동시에 수행하는 배기가스 처리 시스템.When the pH of the aqueous solution decreases and becomes acidic, the exhaust gas treatment system simultaneously performs desulfurization and denitrification by introducing the Ca-based desulfurization agent into the aqueous solution storage tank. 제 5 항에 있어서,According to claim 5, 상기 수용액의 pH가 4 이하로 떨어질 때, 상기 수용액 저장조에 상기 Ca계열의 탈황제를 투입시키는 탈황 및 탈질을 동시에 수행하는 배기가스 처리 시스템.When the pH of the aqueous solution falls below 4, the exhaust gas treatment system simultaneously performs desulfurization and denitrification by introducing the Ca-based desulfurization agent into the aqueous solution storage tank. 제 4 항에 있어서,According to claim 4, 상기 Ca계열의 탈황제를 저장하는 탈황제 저장조; 및 a desulfurization agent storage tank for storing the Ca-based desulfurization agent; and 상기 pH 센서에서 측정된 값을 수신하여 상기 수용액의 pH를 기초로 상기 탈황제 저장조에 저장된 Ca 계열의 탈황제를 상기 수용액 저장탱크로 공급하는 시기를 제어하는 제어부를 포함하는 탈황 및 탈질을 동시에 수행하는 배기가스 처리 시스템.Exhaust that simultaneously performs desulfurization and denitrification including a control unit receiving the value measured by the pH sensor and controlling the supply timing of the Ca-based desulfurization agent stored in the desulfurization agent storage tank to the aqueous solution storage tank based on the pH of the aqueous solution gas handling system. 제 1 항에 있어서,According to claim 1, 상기 Ca 계열의 탈황제는 CaCO3를 포함하는 탈황 및 탈질을 동시에 수행하는 배기가스 처리 시스템.The Ca-based desulfurization agent simultaneously performs desulfurization and denitrification including CaCO 3 . 제 3 항에 있어서,According to claim 3, 상기 Ca 계열의 탈황제는 CaCO3이고, The Ca-based desulfurization agent is CaCO 3 , 상기 KI의 농도는 0.2M 내지 0.3M인 탈황 및 탈질을 동시에 수행하는 배기가스 처리 시스템.The concentration of the KI is 0.2M to 0.3M exhaust gas treatment system that simultaneously performs desulfurization and denitrification. 제 3 항에 있어서,According to claim 3, 상기 냉각부의 전단부에 배치되며 배기가스에 포함된 NOx를 저감하는 선택적 촉매환원장치(Selective Catalytic Reduction: SCR)를 더 포함하는 탈황 및 탈질을 동시에 수행하는 배기가스 처리 시스템.An exhaust gas treatment system that simultaneously performs desulfurization and denitrification, further comprising a selective catalytic reduction (SCR) disposed at a front end of the cooling unit and reducing NOx contained in exhaust gas.
PCT/KR2021/018865 2021-07-20 2021-12-13 Exhaust gas processing system comprising desulfurization and denitrification Ceased WO2023003104A1 (en)

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