HK1233999B - System for treating exhaust gas - Google Patents

Description

Systems for treating exhaust gases

Technical Field

The present invention relates to a system for treating exhaust gas, and more particularly, to a system for treating exhaust gas, whereby the exhaust gas can be treated by using acid and alkali generated in an electrodialysis unit and an oxidant generated in an electrolysis unit.

Background Art

In recent years, various air pollutants such as exhaust gases generated in the process of burning fossil fuels, harmful gases generated in various chemical processes, and waste gases generated in the process of treating wastewater have been increasing due to industrial development.

A typical method for treating such air pollutants is to use a wet scrubber to absorb or oxidize the air pollutants. A method for treating various air pollutants using a wet scrubber has been disclosed in Korean Patent Application Publication No. 10-2010-0106267 (entitled "Control Method of Immersed Scrubber").

This disclosed technology is configured to precipitate substances in exhaust gas by spraying liquid through nozzles in the purifier, but this physical form has limitations in treating air pollutants.

Considering this problem, technologies using oxidants such as NaOCl or NaClO ₂ or chemicals such as NaOH have been intensively studied and developed in recent years to increase the absorption or oxidation efficiency of wet scrubbers.

Figure 1 shows a system for treating exhaust gas, as disclosed in Korean Patent Application No. 10-2012-0090030, which uses an oxidant generated in an electrolytic cell to treat exhaust gas that has passed through a purifier (reaction/absorption tower). Specifically, the system electrolyzes seawater in the electrolytic cell to produce NaOH and HOCl, which are then supplied to the reaction/absorption tower as a reaction liquid (absorbent) to treat the exhaust gas.

However, in the system for treating exhaust gas, the main purpose of the primary reaction/absorption tower is to oxidize nitrate gas in a form that can be easily absorbed using [ _Cl2 /HOCl/OCl] etc., a chlorinated oxidant produced by electrolysis of chlorine in an acidic region, and the secondary reaction/absorption tower is configured to treat exhaust gas by providing a reaction liquid (absorbent) in an alkaline region that easily absorbs _NOx , _CO2 , _SOx , etc.

In the prior art, anode electrolyzed water (chlorinated oxidant in the acidic region) and cathode electrolyzed water (caustic soda in the alkaline region) are provided, which are produced by electrolytic reactions of primary and secondary reaction liquids (absorbent) at the anode and cathode in a diaphragm electrolytic cell. However, although the concentration can be slightly adjusted based on the DC power supply supplied to one electrolytic cell and the flow rate of the inlet water when producing the reaction liquid (absorbent), it is difficult to produce the primary and secondary reaction liquids (absorbent) with optimized compositions for treating exhaust gas.

In particular, according to the prior art, chloride ions and hydrogen ions are generated by competing reactions at the anode, and hydroxyl ions are also generated by an independent reaction in the electrolysis reaction, making it more difficult to adjust the balance of substances.

Prior art literature

Patent Literature

Korean Patent Application No. 10-2012-0090030 (Purification system having a device for automatically generating an oxidizing-absorbent)

Summary of the Invention

Technical issues

The present invention was made in view of the above problems. An object of the present invention is to provide a system for treating exhaust gas, whereby the production of reaction liquid (absorbent) capable of treating exhaust gas is increased by using an electrodialysis device and an electrolysis device, and the reaction liquid is manufactured into a substance with an optimized composition in the main and secondary reaction/absorption towers, so that the exhaust gas can be treated more efficiently.

Technical Solution

To achieve the objectives of the present invention, a system for treating exhaust gas includes: an electrodialysis unit that uses electromotive force to generate alkali and acid from a raw material including seawater or brine; an electrolysis unit that generates a chlorinated oxidant by electrolyzing chloride ions in the raw material; a main reaction/absorption tower that uses the chlorinated oxidant in the acidic region generated by the electrodialysis unit and the electrolysis unit to mainly treat the exhaust gas flowing into the interior through an exhaust gas inlet; and a primary reaction/absorption tower that is connected to the main reaction/absorption tower and uses the alkaline solution generated by the electrodialysis unit to treat the exhaust gas to be mainly treated.

The system may further include: an alkali supply line that provides the alkaline solution produced in the electrodialysis device to the secondary reaction/absorption tower; an acid supply line that provides the acidic solution produced in the electrodialysis device; and an oxidant supply line that provides the main reaction liquid (absorbent) to the main reaction/absorption tower, wherein the main reaction liquid (absorbent) is produced by providing the acidic solution to either the front end or the rear end of the electrolysis device via the acid supply line and then mixing it with the oxidant produced in the electrolysis device.

The system may further include: a circulation line for conveying some of the reaction liquid discharged after being used in the primary reaction/absorption tower and the secondary reaction/absorption tower to the electrodialysis unit or the electrolysis unit.

The system may further include: a first circulation line for transporting some of the primary reaction liquid discharged after use in the primary reaction/absorption tower to an oxidant supply line; and a second circulation line for transporting some of the secondary reaction liquid discharged after use in the secondary reaction/absorption tower to an alkali supply line.

The system may further include: a raw water supplement line for supplementing raw water to the alkali supply line and the oxidant supply line, so that the diluted raw water is provided to the primary reaction/absorption tower or the secondary reaction/absorption tower.

The system may further include: a third reaction/absorption tower, which is disposed on the upstream side of the main reaction/absorption tower or the downstream side of the secondary reaction/absorption tower and purifies the raw water.

An acid supply line may be connected to the electrolysis device to supply the acidic solution generated in the electrodialysis device to a front end of the electrolysis device.

The system may further include: a raw water supply line providing raw water to the acid supply line.

The acid supply line may connect the electrodialysis unit and the oxidant supply line to each other, and the oxidant supply line may connect the electrolysis unit and the main reaction/absorption tower to each other to supply the oxidant generated after electrolysis in the electrolysis unit to the main reaction/absorption tower.

The system further includes: a raw water supply line that provides a raw material including seawater or brine as influent to the electrolysis device; and an electrolyzed water discharge line that is connected to the electrolysis device to discharge electrolyzed water produced by electrolysis of the raw water provided to the electrolysis device, wherein the electrolyzed water supply line can be connected to the acid supply line so that the oxidant supply line supplies the produced oxidant to the main reaction/absorption tower.

The electrolysis device can be a diaphragm electrolysis cell, wherein the cathode chamber and the anode chamber are separated by a diaphragm, and the inflow lines of the anode chamber and the cathode chamber can be connected to one or more raw water supply lines and acid supply lines to provide the acid solution produced in the electrodialysis device, raw water, or a mixture of the acid solution and raw water as the inflow water of the cathode chamber and the anode chamber.

The system may further include: a first electrolyzed water discharge line for discharging the electrolyzed water in the cathode chamber; and a second electrolyzed water discharge line for discharging the electrolyzed water in the anode chamber, wherein the second electrolyzed water discharge line may be connected to the oxidant supply line.

The first electrolyzed water discharge line may be connected to supply the electrolyzed water in the cathode chamber of the diaphragm electrolyzer to the anode chamber of the diaphragm electrolyzer.

The first electrolyzed water discharge line may be connected to an alkali supply line connected to the secondary reaction/absorption tower.

The first electrolyzed water discharge line may be connected to the electrodialysis device for circulation.

The second electrolyzed water discharge line can be connected to the acid supply line of the electrodialysis unit to provide the main reaction liquid (absorbent) to the oxidant supply line, which is produced by mixing the acidic solution produced in the electrodialysis unit with the oxidant produced in the electrolysis unit.

The electrodialysis device may have a three-chamber (acid-generating chamber, alkali-generating chamber, and desalination chamber) structure, including: a cation exchange membrane, an anion exchange membrane, and a bipolar ion membrane.

The electrodialysis unit may have two compartments (an acid-generating compartment and an alkali-generating compartment), including: a bipolar ion membrane and a cation exchange membrane, or a bipolar ion membrane and an anion exchange membrane.

Beneficial effects

According to the system for treating exhaust gas of the present invention, since it includes an electrodialysis device and an electrolysis device, NaOH can be produced in the electrodialysis device and the alkaline solution can be provided to the secondary reaction/absorption tower, and the acidic solution produced in the electrodialysis device and the oxidant produced in the electrolysis device can be provided to the main reaction/absorption tower.

Therefore, the reaction liquid for the main and secondary reaction/absorption towers can be sufficiently produced and provided. Therefore, the reaction liquid having the optimal composition for treating the exhaust gas can be produced, thereby improving the speed of treating the exhaust gas.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is a diagram schematically showing the configuration of a system for processing exhaust gas in the prior art;

2 is a schematic diagram showing the configuration of a system for processing exhaust gas according to a first embodiment of the present invention;

FIG3 is a schematic diagram showing the electrodialysis device shown in FIG2 ;

FIG4 is a schematic diagram illustrating another example of the electrodialysis device shown in FIG3 ;

5 is a schematic diagram illustrating the configuration of a system for processing exhaust gas according to a second embodiment of the present invention;

6 is a schematic diagram illustrating the configuration of a system for processing exhaust gas in a third embodiment according to the present invention;

7 is a schematic diagram illustrating the configuration of a system for processing exhaust gas according to a fourth embodiment of the present invention;

8 is a schematic diagram illustrating the configuration of a system for processing exhaust gas according to a fifth embodiment of the present invention;

9 is a schematic diagram illustrating the configuration of a system for processing exhaust gas according to a sixth embodiment of the present invention;

10 is a schematic diagram illustrating the configuration of a system for processing exhaust gas in a seventh embodiment according to the present invention;

FIG. 11 is a schematic diagram illustrating another embodiment of the system for treating exhaust gas shown in FIG. 2 , in which a third reaction/absorption tower is added.

DETAILED DESCRIPTION

The system for processing exhaust gas according to an embodiment of the present invention will be described in detail below with reference to the accompanying drawings.

2 , a system 100 for treating exhaust gas according to a first embodiment of the present invention includes an electrodialysis unit 110 , an electrolysis unit 120 , a main reaction/absorption tower 130 , and a primary absorption tower 140 .

Electrodialysis device 110 is provided to use seawater (brine) to produce acidic and alkaline liquids, and its unit module is schematically shown in Figures 3 and 4. With reference to Figure 3, electrodialysis device 110 is a three-chamber electrodialysis box, in which cathode 10 and anode 20 are provided, cation exchange membrane 31, bipolar membrane 33 and anion exchange membrane 32 are alternately arranged between cathode and anode, and form a channel (chamber) through which fluid can flow in membrane and electrode. The area between cation exchange membrane 31 and anion exchange membrane 32 is a desalination chamber, the area between cation exchange membrane 31 and the anion exchange layer 33a of bipolar membrane 33 is a base production chamber, and the area between anion exchange membrane 32 and the cation exchange layer 33b of bipolar membrane 33 is an acid production chamber. In addition, the area between electrode and membrane is an electrode chamber, wherein electrode solution is separately provided to the electrode chamber.

In the electrodialysis device 110, a sodium chloride aqueous solution (NaCl), such as seawater (brine), is supplied to the desalination chamber, and water ( _H2O ) (or seawater) is supplied to the acid and alkali generating chambers. Various ionically conductive electrolyte solutions can be used as the electrode solutions supplied to the electrode chambers. Preferably, electrolytes that do not contain chloride ions ( ^Cl- ), such as caustic soda (NaOH) and sodium _sulfate ( _Na2SO4 ), can be used. The reason for using an electrolyte that does not contain chloride ions ( ^Cl- ) is that chloride ions ( ^Cl- ) are converted to chlorine gas ( _Cl2 ) or hypochlorous acid ( ^OCl- ) at the anode by the electromotive force provided by electrodialysis, which can reduce the life of the membrane, corrode the equipment, and deteriorate operator safety.

When a solution (brine and water) is injected and a DC power source is applied to both ends of the electrodes 10 and 20, sodium ions (Na ⁺ ) in a sodium chloride (NaCl) solution provided in the desalination chamber between the cation exchange membrane 31 and the anion exchange membrane 32 move toward the cathode and flow into the alkali generating chamber through the cation exchange membrane 31, while chloride ions (Cl ⁻ ) move toward the anode and flow into the acid generating chamber through the anion exchange membrane 32.

Furthermore, as water decomposes around bipolar membrane 33, hydroxyl ions (OH ⁻ ) exit anion exchange layer 33a in the alkali-generating chamber in contact with cation exchange membrane 31 and bond to sodium ions (Na ⁺ ), thereby producing caustic soda (NaOH) as an alkaline solution. In the acid-generating chamber in contact with anion exchange membrane 32, hydrogen ions (H ⁺ ) exit cation exchange layer 33b and bond to chloride ions (Cl ⁻ ), thereby producing hydrochloric acid (HCl) as an acidic solution. Through this process, electrodialysis 110, which includes a bipolar membrane, can generate both acid (HCl) and base (NaOH) using an alkaline solution (NaCl).

According to the embodiment shown in Figure 4, the electrodialysis device 110' is a two-chamber electrodialysis box, in which a cathode 10 and an anode 20 are provided, and a cation exchange membrane 31 and a bipolar membrane 33 are alternately arranged between the electrodes 10 and 20 (see Figure 4 (a)), or an anion exchange membrane 32 and a bipolar membrane 33 are alternately arranged between the electrodes (see Figure 4 (b)), and a channel (chamber) through which the solution can flow is defined in the membrane and the electrodes. In the two-chamber electrodialysis box including the cation exchange membrane 31 and the bipolar membrane 33, the area between the cation exchange membrane 31 and the cation exchange layer 33b of the bipolar membrane 33 is an acid-generating chamber, and the area between the cation exchange membrane 31 and the anion exchange layer 33a of the bipolar membrane 33 is an alkali-generating chamber. Similar to the three-chamber electrodialysis box, the space between the electrodes and the membrane is the electrode chamber, wherein in the two-chamber electrodialysis box, the electrode solution is provided to the electrode chamber.

In the electrodialysis unit 110', an aqueous sodium chloride solution (NaCl), such as seawater (brine), is supplied to the acid-generating chamber, and water ( _H2O ) (or seawater) is supplied to the alkali-generating chamber. When the solutions are supplied to the chambers and a DC power source is applied across electrodes 10 and 20, sodium ions (Na ⁺ ) from the sodium chloride solution (NaCl) move through the cation exchange membrane 31 to the alkali-generating chamber, while chloride ions ( ^Cl- ) are unable to pass through the cation exchange membrane 31 and remain in the acid-generating chamber.

Water decomposition occurs in the bipolar membrane 33, so hydrogen ions (H ⁺ ) come out of the cation exchange layer 33 b in contact with the acid generating chamber and bond to chloride ions (Cl ⁻ ) that are unable to move from the acid generating chamber to the alkali generating chamber and are retained, thereby producing hydrochloric acid (HCl). Hydroxyl ions (OH ⁻ ) come out of the anion exchange layer 33 a of the bipolar membrane 33 and bond to sodium ions (Na + ) that pass through the cation exchange membrane 31 and enter the alkali generating chamber, thereby producing caustic soda (NaOH).

Regarding the electrodialysis device including the anion exchange membrane 32 and the bipolar membrane 33, which is another two-chamber electrodialysis device 110", it has the same configuration except that the anion exchange membrane 32 is used instead of the cation exchange membrane 31. However, the two-chamber electrodialysis device 110" is different in that a sodium chloride solution (NaCl) such as seawater (brine) is supplied to the alkali-generating chamber, water ( _H2O ) (or seawater) is supplied to the acid-generating chamber, chloride ions ( ^Cl- ) move from the alkali-generating chamber to the acid-generating chamber through the anion exchange membrane 32, and sodium ions (Na ⁺ ) remain in the alkali-generating chamber.

Through this process, electrodialysis 110, which includes a bipolar membrane, can generate acid (HCl) and base (NaOH) using an alkaline solution (NaCl). Because the chlorinated oxidant is generated by electrolyzing chloride ions (Cl ^- ) using electrolysis device 120, which is a post-treatment, a two-chamber electrodialysis device including cation exchange membrane 31 and bipolar membrane 33 in two-chamber electrodialysis device 110 can be considered as a preferred configuration of the present invention.

The acid (HCl) generated in the electrodialysis device 110 is supplied to the front end or rear end of the electrolysis device 120 through the acid supply line 111. In addition, the alkali (NaOH) generated in the electrodialysis device 110 is supplied to the secondary reaction/absorption tower 140 through the alkali supply line 113.

Electrolysis device 120 electrolyzes seawater (brine) to generate a chlorinated oxidant by electrolyzing chloride ions (Cl ⁻ ) in the seawater (brine). The chlorinated oxidant is then mixed with acid (HCl) generated in electrodialysis device 110 at the rear end of electrolysis device 120 to generate the chlorinated oxidant in an acidic region. Alternatively, an acidic (HCl) solution generated and provided by electrodialysis device 110 is provided at the front end of electrolysis device 120 and electrolyzed to generate the chlorinated oxidant in an acidic region. The chlorinated oxidant generated in this manner generates an oxidant such as an oxidant (Cl ₂ /HOCl/OCl ⁻ ) in an acidic region having a pH of 6 or less. This oxidant is supplied to main reaction/absorption tower 130 via oxidant supply line 121. Electrolysis device 120 can have various structures, for example, it can include: a non-diaphragm electrolytic cell in which an anode and a cathode are arranged to correspond to each other in electrolysis device 120; or a diaphragm electrolytic cell having a diaphragm between the anode and the cathode.

Main reaction/absorption tower 130 includes an exhaust gas inlet 131 formed at the bottom to receive exhaust gas, and an oxidant inlet 132 formed at the top to receive oxidant from electrolysis unit 120. A nozzle 133 and a packing 134 for injecting the oxidant may be provided in main reaction/absorption tower 130. Nozzle 133 and packing 134 may be configured in any manner as long as the exhaust gas and oxidant can properly contact each other and chemical reaction and absorption can smoothly occur, and thus the configuration and structure are not limited.

The primary reaction occurring in primary reaction/absorption tower 130 is the oxidation and removal of _NOx in the exhaust gas by the oxidant. Specifically, the exhaust gas contains _CO2 , _NOx , and _SOx , among which NO is oxidized to _NO2 through the primary process, which can be easily absorbed in primary reaction/absorption tower 130. The oxidized _NO2 is then transferred to and absorbed in secondary reaction/absorption tower 140.

The secondary reaction/absorption tower 140 is connected to the main reaction/absorption tower 130 through a connecting channel 135, and receives harmful gases at the lower part of the main reaction/absorption tower 130. The connecting channel 135 connects the upper part of the main reaction/absorption tower 130 and the lower part of the secondary reaction/absorption tower 140 to each other. Although in an embodiment of the present invention, the main reaction/absorption tower 130 and the secondary reaction/absorption tower 140 are connected as an integrated reaction/absorption tower through the connecting channel 135, the present invention is not limited thereto, and the main reaction/absorption tower and the secondary reaction/absorption tower can be separate reaction/absorption towers connected by connecting components such as pipes, or can be formed as a multi-stage reaction/absorption tower that provides main and secondary reaction liquids (absorbents) in several steps.

The secondary reaction/absorption tower 140 may include: an alkaline solution inlet 141, to which the alkali supply line 113 is connected; a nozzle 142 for spraying the acidic solution (NaOH) supplied through the alkaline solution inlet 141 within the tower; and a filler 143 disposed therein. This configuration and structure are not limited and are similar to those of the primary reaction/absorption tower. A treated gas outlet 144 for discharging treated gas is formed at the top. In the secondary reaction/absorption tower 140, the _NO2 treated by the primary reaction/absorption tower 130 and the untreated _CO2 and SOx provided are absorbed and treated by the alkaline solution (NaOH), and the discharged gas is treated through other chemical reactions.

The outlet for discharging the wastewater after the treatment of the primary and secondary reaction liquids (absorbents) is formed at the lower portion of the primary and secondary reaction/absorption towers 130 and 140, and the wastewater from one outlet meets the wastewater from the other outlet at the junction of the discharge lines 137 and 145, and then the remaining neutralized acidic solution and alkaline solution are discharged. In addition, a specific neutralization/precipitation tank 150 can be additionally provided at a predetermined position of the discharge line. Condensation and precipitation are performed in the neutralization/precipitation tank 150, and the wastewater passing through the neutralization/precipitation tank 150 is discharged through the discharge line 115 connected to the wastewater discharge line 114. A specific filter can be provided after the neutralization/precipitation tank 150 to filter the wastewater discharged after condensation and precipitation.

Some of the reaction liquid discharged through the discharge lines 137 and 145 after being used in the main reaction/absorption tower and the secondary reaction/absorption tower can be returned to the front end of any one or more of the electrodialysis unit 110 and the electrolysis unit 120 to be reused by further installing circulation lines 136 and 146 separated from the discharge lines 137 and 145.

According to another method, the main reaction liquid discharged from the reaction/absorption tower 130 through the discharge line 137 and the secondary reaction liquid discharged from the secondary reaction/absorption tower 140 through the discharge line 145 can be reused by configuring the circulation lines 136 and 146 to transport the main reaction liquid and the secondary reaction liquid to the oxidant supply line 121 and the alkali supply line 113, respectively.

In addition, a raw water replenishment line 160 may be further provided for supplying seawater or salt water (NaCl) to the oxidant supply line 121 and the alkali supply line 113. Since seawater or salt water (NaCl) is replenished to the primary and secondary reaction/absorption towers 130 and 140 through the raw water replenishment line 160, the pH of the absorbent (reaction liquid) and the concentration of the oxidant can be appropriately adjusted.

In addition, a third reaction/absorption tower for purifying raw water can be additionally provided on the upstream side of the main reaction/absorption tower or on the downstream side of the secondary reaction/absorption tower. Figure 11 shows an example in which the third reaction/absorption tower 140' is provided on the upstream side of the main reaction/absorption tower 130. The third reaction/absorption tower 140' can have a structure and shape similar to those of the main and secondary reaction/absorption towers 130 and 140. In the third reaction/absorption tower 140', the main purpose is to remove dirt, dust and oil generated by the engine and present in the inflowing exhaust gas, and in addition to discharging unreacted substances and the main and secondary reaction liquids in the form of fine particles as a final treatment.

As described above, according to an embodiment of the present invention, since acid and alkali are generated by the electrodialysis device 110 and the generated acidic solution (NaOH: absorbent) is directly provided to the secondary reaction/absorption tower 140, optimal conditions of the absorbent (reaction liquid) for secondary treatment of exhaust gas can be achieved.

Furthermore, by providing an oxidant in the acidic region generated by mixing the acidic solution generated in the electrodialysis unit 110 with the oxidant generated by electrolysis in the electrolysis unit 120, NO contained in the exhaust gas can be oxidized into easily absorbable NO ₂ , thereby enabling NO _x , SO _x , and CO ₂ to be effectively absorbed and removed using an absorbent (NaOH) in the secondary treatment. That is, in addition to CO ₂ , even NO _x and SO _x can be effectively removed.

Therefore, the speed of processing exhaust gas can be improved, and the reliability of exhaust gas processing can be improved by producing the reaction/absorbent to have a composition most suitable for primary and secondary reactions and absorption.

FIG5 is a schematic diagram illustrating a unique configuration of a system 100′ for treating exhaust gas according to a second embodiment of the present invention. Referring to FIG5 , an electrodialysis unit 110 uses seawater (brine) to produce an acidic solution (HCl) and an alkaline solution (NaOH). The acidic solution (HCl) produced by the electrodialysis unit 110 is supplied to the electrolysis unit 120 via an acid supply line 111, thereby generating an oxidant in the acidic region. The oxidant produced by the electrolysis unit 120 is supplied to the primary reaction/absorption tower 130 via an oxidant supply line 121, and the alkaline solution (NaOH) produced by the electrodialysis unit 110 is supplied to the secondary reaction/absorption tower 140 via an alkali supply line 113, thereby treating the exhaust gas flowing into the primary and secondary reaction/absorption towers 130 and 140. A raw water supply line 171 for supplying raw water can be additionally connected to the acid supply line 111. According to this configuration, an oxidant having a predetermined factor suitable for the primary reaction/absorption tower 140 can be generated by additionally supplying seawater (brine).

6 is a schematic diagram illustrating a unique configuration of a system 110″ for treating exhaust gas according to a third embodiment of the present invention. Referring to FIG6 , in the system 100″ for treating exhaust gas according to the third embodiment of the present invention, the electrodialysis unit 110 generates an acidic solution (HCl) and an alkaline solution (NaOH) using raw water (seawater or brine), and the electrolysis unit 120 generates electrolyzed water as a chlorination oxidant by electrolyzing the raw water (seawater or brine) directly provided via the raw water supply line 172. The electrolyzed water has a pH exceeding the neutral region, and the acidic solution (HCl) generated by the electrodialysis unit 110 is supplied via the acid supply line 111′ to manufacture the electrolyzed water into an oxidant in an appropriate acidic region in the reaction liquid (absorbent) used in the main reaction/absorption tower. The oxidant in the acidic region is supplied to the main reaction/absorption tower 130 via the oxidant supply line 121′. In addition, the acidic solution (NaOH) generated by the electrodialysis unit 110 is supplied to the secondary first reaction/absorption tower 140 via the alkali supply line 113, thereby generating exhaust gas.

FIG7 is a schematic diagram illustrating a unique configuration of a system 200 for treating exhaust gas according to a fourth embodiment of the present invention. Referring to FIG7 , the system 200 for treating exhaust gas according to the fourth embodiment of the present invention features a diaphragm electrolyzer, wherein a diaphragm 120c is disposed between a cathode 120a and an anode 120b, defining a cathode chamber A and an anode chamber B within an electrolysis unit 120'. In this case, an acidic solution (HCl) generated by an electrodialysis unit 110 is supplied to the cathode chamber A of the electrolyzer via an acid supply line 111 and electrolyzed therein. Electrolyzed water generated at the cathode is supplied to the anode chamber B of the electrolyzer via a first electrolyzed water discharge line 123 and electrolyzed therein, thereby generating an oxidant in the acidic region. The oxidant is supplied to a primary reaction/absorption tower via an oxidant supply line 121. Furthermore, an acidic solution (NaOH) generated by the electrodialysis unit 110 is supplied to a secondary first reaction/absorption tower via an alkali supply line 113, thereby treating the exhaust gas. Raw water supply lines 173 and 174 for additionally supplying raw water (seawater or brine) may be additionally connected to the acid supply line 111 or the first electrolyzed water discharge line 123 to generate an oxidant suitable for the main reaction/absorption tower.

When seawater is used as raw water in this configuration, scale generation at the cathode 120 a can be prevented due to the scale inducer in the seawater, and thus the oxidant can be stably generated and the durability of the electrolysis device 130 can be improved.

FIG8 is a schematic diagram illustrating a unique configuration of a system 200′ for treating exhaust gas according to a fifth embodiment of the present invention. Referring to FIG8 , the system 200′ for treating exhaust gas according to the fifth embodiment has a configuration in which raw water (seawater or brine) supplied via raw water supply line 175 is simultaneously supplied to cathode chamber A and anode chamber B, and the raw water is electrolyzed using the diaphragm electrolytic cells of electrolysis device 120′. Furthermore, the electrolyzed water produced in cathode chamber A of electrolysis device 120′ is supplied to secondary reaction/absorption tower 140 via first electrolyzed water discharge line 124 and alkali supply line 113. In addition, a second electrolyzed water discharge line 125 for discharging electrolyzed water generated in the anode chamber B of the electrolysis device 120′ is connected to the acid supply line 111″ to supply acid (HCl) generated in the electrodialysis device 110. The oxidant in the acidic region formed by connecting the second electrolyzed water discharge line 125 and the acid supply line 111 is supplied to the main reaction/absorption tower 130 through the oxidant supply line 121, thereby treating the exhaust gas.

9 is a schematic diagram illustrating a unique configuration of a system 200″ for treating exhaust gas according to a sixth embodiment of the present invention. Referring to FIG9 , the system 200′ for treating exhaust gas according to the sixth embodiment of the present invention is configured so that the acidic solution (HCl) produced in the electrodialysis unit 110 is supplied to the cathode chamber A of the diaphragm electrolysis unit 120′, and raw water (seawater or brine) is supplied to the anode chamber B through a raw water supply line 176. When the raw water is supplied and electrolyzed, the pH of the acidic solution (HCl) in the cathode chamber A increases, and an oxidant in the acidic region is produced by electrolysis in the anode chamber B. Electrolyzed water, that is, the oxidant produced by electrolysis in the anode chamber B is supplied to the main reaction/absorption tower 130 through an oxidant supply line 121′. In addition, a first electrolyzed water circulation line 124′ may connect the cathode chamber A and the acid generating chamber of the electrodialysis unit 110 so that the electrolyzed water produced in the cathode chamber A is transported to the acid generating chamber of the electrodialysis unit 110.

FIG10 is a schematic diagram illustrating a unique configuration of a system 300 for treating exhaust gas according to a seventh embodiment of the present invention. Referring to FIG10 , the system 300 for treating exhaust gas according to the seventh embodiment of the present invention is modified from the embodiment shown in FIG9 , and is characterized in that the acid (HCl) generated in the electrodialysis unit 110 and the raw water (seawater or brine) are simultaneously supplied to the cathode chamber A and the anode chamber B of the diaphragm electrolyzer of the electrolysis unit 120 ′. To this end, the acid supply line 111 has first and second branch lines 111 a and 111 b to separately supply the acid to the cathode chamber A and the anode chamber B. Furthermore, a raw material supplier 176 ′ is connected to the acid supply line 111 so that the raw material can be separately supplied to the cathode chamber A and the anode chamber B of the electrolysis cell.

According to the exhaust gas treatment system of various embodiments described above, the electrodialysis device and a membrane or non-membrane electrolyzer can efficiently generate and provide the reaction liquids required for exhaust gas treatment in the primary and secondary reaction/absorption towers 130 and 140, namely, the oxidant in the acidic region and the alkaline solution used in this configuration. Furthermore, the appropriate amount and concentration of reaction liquids in the primary and secondary reaction/absorption towers can be achieved and provided, thereby improving exhaust gas treatment efficiency.

<Description of Reference Numerals in the Drawings>

100, 100’, 100”, 200, 200’, 200”, 300 Exhaust gas treatment systems

110 Electrodialysis Unit

120, 120' electrolysis device

130 Main reaction/absorption tower

140 reactions/absorption towers

140’ third reaction/absorption tower

150 Neutralization/Sedimentation Tank

Claims (18)

1. A system for treating exhaust gases, characterized in that it comprises: An electrodialysis device that uses electromotive force to produce alkali and acid from raw materials including seawater or brine; An electrolysis device that generates a chlorinating oxidant by electrolyzing chloride ions in raw materials; A main reaction/absorption tower, using a chlorinating oxidant generated in the acidic zone by the electrodialysis and electrolysis units, primarily treats the exhaust gases flowing into the tower through the exhaust gas inlet; and A primary reaction/absorption tower is connected to the main reaction/absorption tower and uses an alkaline solution generated by an electrodialysis unit to treat the exhaust gas that is primarily being treated. 2. The system as claimed in claim 1, further comprising: An alkali supply line will supply the alkaline solution generated in the electrodialysis unit to the secondary reaction/absorption tower; An acid supply line provides the acidic solution generated in the electrodialysis unit; and An oxidant supply line supplies the main reaction liquid to the main reaction/absorption tower, which is produced by mixing an acidic solution supplied via an acid supply line to either the front or back end of the electrolysis unit with the oxidant generated in the electrolysis unit. 3. The system as claimed in claim 2, further comprising: a circulation pipeline for conveying some of the reaction liquid discharged after use in the main reaction/absorption tower and the secondary reaction/absorption tower to the electrodialysis unit or the electrolysis unit. 4. The system as claimed in claim 2, further comprising: A first circulation line will transport some of the main reaction liquid discharged after use in the main reaction/absorption tower to the oxidant supply line; and A second circulation pipeline will transport some of the secondary reaction liquid discharged after use in the secondary reaction/absorption tower to the alkali supply line. 5. The system as claimed in claim 2, further comprising: a raw water replenishment line for replenishing raw water to the alkali supply line and the oxidant supply line, so as to provide diluted raw water to the main reaction/absorption tower or the secondary reaction/absorption tower. 6. The system according to any one of claims 1 to 5, characterized in that it further comprises: a third reaction/absorption tower, disposed upstream of the main reaction/absorption tower or downstream of the secondary reaction/absorption tower, for purifying the raw water. 7. The system according to any one of claims 2 to 5, characterized in that the acid supply line is connected to the electrolysis device to provide the acidic solution generated in the electrodialysis device to the front end of the electrolysis device. 8. The system as claimed in claim 7, further comprising: a raw water supply line for supplying raw water to the acid supply line. 9. The system according to any one of claims 2 to 5, characterized in that the acid supply line connects the electrodialysis unit and the oxidant supply line to each other, and the oxidant supply line connects the electrolysis unit and the main reaction/absorption tower to each other, so as to provide the oxidant generated after electrolysis in the electrolysis unit to the main reaction/absorption tower. 10. The system according to any one of claims 2 to 5, characterized in that it further comprises: A raw water supply line provides seawater or brine as feed water to the electrolysis unit; and An electrolyzed water discharge line is connected to the electrolysis unit to discharge the electrolyzed water produced from the raw water supplied to the electrolysis unit through electrolysis. The electrolyzed water supply line is connected to the acid supply line so that the oxidant supply line can supply the generated oxidant to the main reaction/absorption tower. 11. The system according to any one of claims 2 to 5, characterized in that the electrolysis device is a diaphragm electrolyzer, wherein the cathode chamber and the anode chamber are separated by a diaphragm, and the inflow lines of the anode chamber and the cathode chamber are connected to one or more raw water supply lines and acid supply lines to provide acidic solution, raw water, or a mixture of acidic solution and raw water generated in the electrodialysis device as feed water to the cathode chamber and the anode chamber. 12. The system of claim 11, further comprising: A first electrolyzed water discharge pipeline discharges the electrolyzed water from the cathode chamber; and A second electrolyzed water discharge pipeline discharges the electrolyzed water from the anode chamber; The second electrolyzed water discharge pipeline is connected to the oxidant supply line. 13. The system of claim 12, wherein a first electrolyzed water discharge line is connected to supply electrolyzed water from the cathode chamber of the diaphragm electrolyzer to the anode chamber of the diaphragm electrolyzer. 14. The system as claimed in claim 12, wherein the first electrolyzed water discharge line is connected to the alkali supply line connected to the secondary reaction/absorption tower. 15. The system as claimed in claim 12, wherein the first electrolyzed water discharge line is connected to the electrodialysis device for circulation. 16. The system of claim 12, wherein the second electrolyzed water discharge line is connected to the acid supply line of the electrodialysis unit to supply the main reaction liquid to the oxidant supply line, the main reaction liquid being generated by mixing an acidic solution generated in the electrodialysis unit with an oxidant generated in the electrolysis unit. 17. The system according to any one of claims 1 to 5, characterized in that the electrodialysis device has a three-chamber structure, comprising: a cation exchange membrane, an anion exchange membrane, and a bipolar ion exchange membrane. 18. The system according to any one of claims 1 to 5, characterized in that the electrodialysis device has a two-chamber structure, comprising: a bipolar ion exchange membrane and a cation exchange membrane, or a bipolar ion exchange membrane and an anion exchange membrane.