KR20220013219A - Apparatus for reducing air pollutant - Google Patents

Abstract

According to one embodiment of the present invention, provided is a device for reducing exhausted contaminants. According to one embodiment of the present invention, the device for reducing exhausted contaminants comprises: an exhaust pipe discharging exhaust gas from a combustion engine; a carbon dioxide reduction unit connected on the exhaust pipe and oxidizing and condensing carbon dioxide contained in the exhaust gas to reduce carbon dioxide concentration of the exhaust gas; a selective catalytic reduction reactor connected to the exhaust pipe of a rear end of the carbon dioxide reduction unit to reduce nitrogen oxide contained in the exhaust gas; and a heat recovery unit recovering heat generated from the carbon dioxide reduction unit to provide the heat to at least one between the selective catalytic reduction reactor and a boiler.

Description

Apparatus for reducing air pollutant

The present invention relates to an exhaust pollutant reduction device, and more particularly, to an exhaust pollutant reduction device capable of increasing device efficiency by utilizing heat generated when reducing carbon dioxide contained in exhaust gas where necessary.

In general, various engines installed in ships generate power by burning fuel, and exhaust gas generated in the process of burning fuel contains nitrogen oxides, sulfur oxides, carbon dioxide, and the like. As air pollution increases, regulations on various harmful substances included in exhaust gas are becoming stricter, and not only nitrogen oxides and sulfur oxides, but also carbon dioxide are subject to emission regulations from the International Maritime Organization (IMO), the United Nations oxidation agency. are receiving In fact, the International Maritime Organization limits the sulfur content of fuel to 0.5% in the global area as well as in the Emission Control Area (ECA) from 2020, and reduces the carbon dioxide emission from 2008 to 2030. It is in the process of reducing it by 40% and reducing it by 70% by 2050.

On the other hand, in the case of sulfur oxides, a method of removing them using a wet scrubber is common, but the performance and price of the scrubber are improved compared to the initial stage, so there is no great difficulty in satisfying the regulations related to the sulfur content of the fuel. However, it is difficult to satisfy the regulations related to the emission of carbon dioxide using the existing fuel efficiency reduction technology unless a low-carbon or de-carbonized fuel is used.

Accordingly, there is a need for a device that can reduce carbon dioxide contained in exhaust gas while maximizing the conventional structure, utilize heat generated when reducing carbon dioxide, and neutralize acidified washing water used in a scrubber became

Republic of Korea Patent Registration No. 10-2031210 (2019. 10. 04.)

An object of the present invention is to provide an exhaust pollutant reduction device capable of increasing device efficiency by utilizing heat generated when reducing carbon dioxide contained in exhaust gas where necessary.

The technical problems of the present invention are not limited to the technical problems mentioned above, and other technical problems not mentioned will be clearly understood by those skilled in the art from the following description.

Exhaust pollutant reduction apparatus according to an embodiment of the present invention for achieving the above technical problem, an exhaust pipe for discharging exhaust gas from a combustion engine, is connected to the exhaust pipe, and oxidizes and aggregates carbon dioxide contained in the exhaust gas a carbon dioxide reduction unit for reducing the carbon dioxide concentration of the exhaust gas, a selective catalytic reduction reactor connected to the exhaust pipe at the rear end of the carbon dioxide reduction unit to reduce nitrogen oxides contained in the exhaust gas, and the carbon dioxide reduction unit generated from and a heat recovery unit that recovers heat and provides it to at least one of the selective catalytic reduction reactor and the boiler.

The carbon dioxide reduction unit includes an oxidation unit that oxidizes the carbon dioxide by reacting the exhaust gas with the oxidizing agent, and is disposed at the rear end of the oxidation unit, and injects a coagulant into the exhaust gas to agglomerate the carbon dioxide oxide generated in the oxidation unit and a coagulation unit, wherein the heat recovery unit may recover heat by exchanging heat with at least one of the oxidation unit and the coagulation unit.

The oxidation unit uses sodium hydroxide (NaoH) solution as the oxidizing agent, the flocculation unit uses calcium hydroxide (Ca(OH) ₂ ) as the flocculation agent, and the heat recovery unit is the heat generated during the flocculation reaction in the flocculation unit. can be recovered

The exhaust pollutant reducing device is connected to a scrubber that is connected to the exhaust pipe at the rear end of the coagulation unit to inject washing water into the exhaust gas, and a washing water discharge pipe for discharging the washing water inside the scrubber, and the washing It may further include a neutralization unit for neutralizing the acidified washing water by injecting a neutralizing agent into water, wherein the sodium hydroxide generated in the aggregation unit is provided to the oxidation unit as the oxidizing agent or to the neutralization unit. .

The heat recovery unit includes at least one first heat exchange tube in which the high-temperature heat medium that has passed through the carbon dioxide reduction unit circulates, and is disposed at one side of the first heat exchange tube, and heats the heat transfer fluid heated by heat exchange with the heat medium. It may include a second heat exchange tube circulating to the selective catalytic reduction reactor to transfer heat to at least one of the urea water and the exhaust gas supplied to the selective catalytic reduction reactor.

The heat recovery unit may further include a third heat exchange tube for transferring heat between the first heat exchange tube and the boiler, wherein the first heat exchange tube first exchanges heat with the second heat exchange tube and then heat exchanges with the third heat exchange tube can do.

According to the present invention, it is possible to effectively reduce carbon dioxide as well as sulfur oxides and nitrogen oxides contained in exhaust gas, so that it is possible to easily satisfy the strengthened regulations of the International Maritime Organization. In particular, since the heat generated when reducing carbon dioxide is recovered and provided to at least one of the selective catalytic reduction reactor and the boiler, it is possible to save fuel as well as increase the device efficiency.

In addition, sodium hydroxide is used as an oxidizing agent for oxidizing carbon dioxide contained in exhaust gas and as a neutralizing agent for neutralizing the acidified washing water by gas-liquid contact with the exhaust gas in the scrubber. Of course, the device configuration is simplified, and the space utilization in a narrow vessel can be increased.

1 is a diagram schematically illustrating an exhaust pollutant reduction device according to an embodiment of the present invention.
FIG. 2 is an enlarged view of the carbon dioxide reduction unit of FIG. 1 .
3 is an exemplary view for explaining the connection between the carbon dioxide reduction unit and the heat recovery unit.
4 is an operation diagram for explaining the operation of the exhaust pollutant reducing device.

Advantages and features of the present invention and methods of achieving them will become apparent 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, but may be implemented in various different forms, and only these embodiments allow the disclosure of the present invention to be complete, and common knowledge in the art to which the present invention pertains It is provided to fully inform those who have the scope of the invention, and the present invention is only defined by the scope of the claims. Like reference numerals refer to like elements throughout.

Hereinafter, an apparatus for reducing exhaust pollutants according to an embodiment of the present invention will be described in detail with reference to FIGS. 1 to 4 .

Exhaust pollutant reduction device according to an embodiment of the present invention is to reduce the concentration of sulfur oxides, nitrogen oxides, and carbon dioxide contained in exhaust gas and to treat the washing water used to reduce the pollutant concentration in the exhaust gas, for example, , it can be installed on ships and used to treat exhaust gas and washing water generated in shipbuilding and offshore fields.

The exhaust pollutant reduction device can effectively reduce carbon dioxide as well as sulfur oxides and nitrogen oxides contained in exhaust gas, and thus can easily satisfy the strengthened regulations of the International Maritime Organization. In particular, since the heat generated when reducing carbon dioxide is recovered and provided to at least one of the selective catalytic reduction reactor and the boiler, it is possible to save fuel as well as increase the device efficiency. In addition, sodium hydroxide is used as an oxidizing agent for oxidizing carbon dioxide contained in exhaust gas and as a neutralizing agent for neutralizing the acidified washing water by gas-liquid contact with the exhaust gas in the scrubber. Of course, there is a feature that the use of space in a narrow vessel can be increased by simplifying the device configuration.

Hereinafter, the exhaust pollutant reducing device 1 will be described in detail with reference to FIGS. 1 to 3 .

1 is a view schematically showing an exhaust pollutant reduction device according to an embodiment of the present invention, FIG. 2 is an enlarged view of the carbon dioxide reduction unit of FIG. 1, and FIG. 3 is a carbon dioxide reduction unit and a heat recovery unit It is an example diagram for explaining the connection state of .

The exhaust pollutant reduction device 1 according to the present invention includes an exhaust pipe 10 , a carbon dioxide reduction unit 20 , a selective catalytic reduction reactor 30 , and a heat recovery unit 40 .

The exhaust pipe 10 is a pipe for discharging exhaust gas from the combustion engine 100 installed in the hull, and one end is connected to the combustion engine 100 and the other end is extended into the atmosphere. Here, the combustion engine 100 refers to a device for generating power required for a ship by burning fuel, and may be, for example, a main engine or a generator engine. The combustion engine 100 generally generates power by burning fossil fuel, and thus generates exhaust gas according to combustion of the fossil fuel. The generated exhaust gas contains a large amount of sulfur oxides, nitrogen oxides, organic materials, fine dust, etc., and is discharged through the exhaust pipe 10 connected to one side of the combustion engine 100 . A carbon dioxide reduction unit 20 is connected on the exhaust pipe 10 .

The carbon dioxide reduction unit 20 oxidizes and aggregates carbon dioxide contained in the exhaust gas to reduce the carbon dioxide concentration of the exhaust gas, and includes an oxidation unit 21 and an aggregation unit 22 .

The oxidation unit 21 oxidizes carbon dioxide contained in the exhaust gas by reacting the exhaust gas with the oxidizing agent, and may be formed in the form of a wet scrubber, for example. The oxidation unit 21 uses a sodium hydroxide (NaOH) solution as an oxidizing agent, and carbon dioxide (CO ₂ ) contained in the exhaust gas reacts with a sodium hydroxide (NaOH) solution and is oxidized according to the following reaction equation.

<reaction formula>

2NaOH + CO ₂ → Na ₂ CO ₃ + H ₂ O

Carbon dioxide (CO ₂ ) is oxidized to become carbon dioxide oxide (Na ₂ CO ₃ ), and the exhaust gas moves to the aggregation unit 22 in a state including carbon dioxide oxide (Na ₂ CO ₃ ). The agglomeration unit 22 aggregates carbon dioxide oxide (Na ₂ CO ₃ ) generated in the oxidation unit 21 by injecting a coagulant into the exhaust gas, and is connected to the exhaust pipe 10 at the rear end of the oxidation unit 21 . The aggregation unit 22 uses powder or ring-shaped calcium hydroxide (Ca(OH) ₂ ) as a coagulant, and carbon dioxide oxide (Na ₂ CO ₃ ) reacts with calcium hydroxide (Ca(OH) ₂ ) to form the following Aggregates according to the reaction equation.

<reaction formula>

Na ₂ CO ₃ + Ca(OH) ₂ → 2NaOH + CaCO ₃

When carbon dioxide oxide (Na ₂ CO ₃ ) causes an aggregation reaction, sodium hydroxide (NaOH) and calcium carbonate (CaCO ₃ ) are produced as by-products. As carbon dioxide (CO ₂ ) is oxidized to carbon dioxide oxide (Na ₂ CO ₃ ), and carbon dioxide oxide (Na ₂ CO ₃ ) is agglomerated into calcium carbonate (CaCO ₃ ), carbon dioxide contained in exhaust gas can be removed, thereby Therefore, it is possible to satisfy the regulations related to carbon dioxide. Since the agglomeration unit 22 is formed as a three-phase separator that separates liquid, solid, and gas, respectively, sodium hydroxide (NaOH) in liquid state, calcium carbonate in a solid state (CaCO ₃ ), and gas produced as a by-product of the agglomeration reaction It is possible to separate the exhaust gas in the state. Calcium carbonate (CaCO ₃ ) can be stored in a separate tank and then transferred to the shore when the ship is anchored in the port and treated as waste.

The exhaust gas from which sodium hydroxide (NaOH) in a liquid state and calcium carbonate (CaCO ₃ ) in a solid state are separated moves to the scrubber 50 connected to the exhaust pipe 10 at the rear end of the aggregation unit 22 . The scrubber 50 removes sulfur oxides (SOx) by spraying washing water to the exhaust gas that has passed through the aggregation unit 22, and the washing water may be at least one of seawater or fresh water or mixed water of seawater and fresh water. . As the washing water is injected into the exhaust gas, pollutants such as sulfur oxides and fine dust included in the exhaust gas may be removed, and thus, regulations related to sulfur oxides may also be satisfied. The exhaust gas passing through the scrubber 50 moves to the selective catalytic reduction reactor 30 .

The selective catalytic reduction reactor 30 reduces nitrogen oxides contained in exhaust gas, and is connected to the exhaust pipe 10 at the rear end of the carbon dioxide reduction unit 20, more specifically, the exhaust pipe 10 at the rear end of the scrubber 50. . The selective catalytic reduction reactor 30 injects the urea water supplied from the urea water storage tank (not shown) to the exhaust gas supplied from the combustion engine 100, whereby the urea water is thermally decomposed by the heat of the exhaust gas to ammonia can be converted to The converted ammonia may pass through a catalyst layer installed inside the reactor together with the exhaust gas to reduce nitrogen oxides contained in the exhaust gas to nitrogen and water. The exhaust gas from which nitrogen oxides have been removed may be discharged into the atmosphere through the exhaust pipe 10 . That is, the exhaust gas from which carbon dioxide, sulfur oxides, fine dust, and nitrogen oxides have been removed by passing through the oxidation unit 21, the aggregation unit 22, the scrubber 50, and the selective catalytic reduction reactor 30 meets the emission standards Therefore, it can be emitted directly into the atmosphere. When the exhaust gas discharged from the combustion engine 100 is at a high temperature of 280°C or higher, as described above, it is possible to thermally decompose the urea water with the heat of the exhaust gas by directly injecting urea water into the exhaust gas, but when the exhaust gas is 280°C In the case of a lower temperature, the urea water cannot be thermally decomposed by the heat of the exhaust gas. Accordingly, heat may be supplied from the heat recovery unit 40 to the selective catalytic reduction reactor 30 in order to purify the low-temperature exhaust gas.

The heat recovery unit 40 recovers heat generated from the carbon dioxide reduction unit 20 and provides it to at least one of the selective catalytic reduction reactor 30 and the boiler 200, and among the oxidation unit 21 and the aggregation unit 22 Heat may be recovered by heat exchange with at least one. More specifically, when carbon dioxide oxide (Na ₂ CO ₃ ) causes an agglomeration reaction in the aggregation unit 22 , sodium hydroxide (NaOH) and calcium carbonate (CaCO ₃ ) are generated as by-products and heat is generated. ) may be provided to at least one of the selective catalytic reduction reactor 30 and the boiler 200 by recovering the heat generated during the coagulation reaction. The heat recovery unit 40 recovers heat and provides it to at least one of the selective catalytic reduction reactor 30 and the boiler 200, thereby reducing fuel consumed in the selective catalytic reduction reactor 30 and the boiler 200. Of course, waste heat can be utilized to improve device efficiency. The heat recovery unit 40 may include at least one first heat exchange tube 41 , a second heat exchange tube 42 , and a third heat exchange tube 43 .

The first heat exchange tube 41 is a tube through which the high-temperature heat medium that has passed through the carbon dioxide reduction unit 20 circulates, for example, as shown in FIG. have. When the first heat exchange tube 41 is formed as one and passes through the aggregation unit 22 , the second heat exchange tube 42 and the third heat exchange tube 43 are respectively formed on one side and the other side of the first heat exchange tube 41 . ) is disposed so that the first heat exchange tube 41 first exchanges heat with the second heat exchange tube 42 , and then heat exchanges with the third heat exchange tube 43 .

The second heat exchange tube 42 is a tube that circulates the heat transfer fluid heated by exchanging heat with the heating medium to the selective catalytic reduction reactor 30, and heats at least one of urea water and exhaust gas supplied to the selective catalytic reduction reactor 30. can convey When the heat transfer fluid flowing through the second heat exchange tube 42 transfers heat to the urea water supplied to the selective catalytic reduction reactor 30, the urea water may be thermally decomposed and converted into ammonia, whereby the exhaust gas is 280 ° C. Even at a lower temperature, there is no need to operate a separate heater to thermally decompose the urea water, thereby saving fuel. When the heat transfer fluid flowing through the second heat exchange tube 42 transfers heat to the exhaust gas supplied to the selective catalytic reduction reactor 30, the reaction temperature may increase to increase the catalytic reaction in the catalyst layer. Although the drawing shows that the second heat exchange tube 42 directly passes through the selective catalytic reduction reactor 30, it is not limited thereto. For example, the second heat exchange tube 42 is the selective catalytic reduction reactor 30. It may pass through the exhaust pipe 10 of the previous stage and pass through the selective catalytic reduction reactor 30 indirectly.

The third heat exchange tube 43 is a tube that transfers heat between the first heat exchange tube 41 and the boiler 200, and circulates a heat transfer fluid heated by exchanging heat with a heat medium to the boiler 200 or heat medium and water. Steam generated by heat exchange may be supplied to the boiler 200 . When the heated heat transfer fluid is circulated to the boiler 200 through the third heat exchange tube 43, a combustion reaction occurs more easily when burning fuel to generate steam in the boiler 200, thereby saving energy. , when steam is supplied to the boiler 200 , it is not necessary to burn fuel to generate steam in the boiler 200 , thereby saving fuel.

In order to thermally decompose urea water in the selective catalytic reduction reactor 30, heat of about 200 to 300° C. is required, and in order to generate steam to be supplied to the boiler 200 or to generate steam directly from the boiler 200, about 100 to 200 Since heat of ℃ is required, as described above, when the first heat exchange tube 41 first exchanges heat with the second heat exchange tube 42 and then exchanges heat with the third heat exchange tube 43, heat while minimizing the device configuration can be effectively conveyed.

However, the first heat exchange tube 41 is not limited to being formed as one and passes through the aggregation unit 22 , and the number and arrangement of the first heat exchange tube 41 may be variously modified. For example, as shown in (a) of FIG. 3, the first heat exchange tube 41 may be formed in two and pass through the aggregation unit 22, as shown in FIG. , may be formed in two and pass through the aggregation unit 22 and the oxidation unit 21, respectively. In addition, although not shown, the first heat exchange tube 41 may be formed as one, and only the oxidation unit 21 may pass therethrough. As shown in (a) of Figure 3, when the first heat exchange tube 41 is formed in two and passes through the aggregation unit 22, any one of the first heat exchange tube ( 41) A second heat exchange tube 42 may be disposed on one side, and a third heat exchange tube 43 may be disposed on one side of the other first heat exchange tube 41 through which a relatively low temperature heat medium flows. In addition, as shown in (b) of FIG. 3, when the first heat exchange tube 41 is formed in two and passes through the aggregation unit 22 and the oxidation unit 21, respectively, it passes through the aggregation unit 22 Thus, the second heat exchange tube 42 is disposed on one side of the first heat exchange tube 41 through which a relatively high temperature heating medium flows, and the first heat exchange in which a relatively low temperature heating medium flows through the oxidation unit 21 . A third heat exchange tube 43 may be disposed on one side of the tube 41 .

Meanwhile, the washing water inside the scrubber 50 is discharged through the washing water discharge pipe 51 , and the neutralization unit 60 and the separation unit (not shown) are connected on the washing water discharge pipe 51 .

The neutralization unit 60 injects a neutralizing agent into the washing water to neutralize the acidified washing water by contacting the exhaust gas with gas-liquid, and uses a sodium hydroxide (NaOH) solution as the neutralizing agent. As the sodium hydroxide solution is injected into the washing water, the hydrogen ion concentration index of the washing water is circulated to the scrubber 50 to be reused or neutralized to a state suitable for discharging to the sea, for example, about pH 6-7. The neutralized washing water may be recycled to the scrubber 50 after the solid materials with large particles are removed in the separation unit and reused or discharged to the sea.

Sodium hydroxide (NaOH) generated as a by-product of the aggregation reaction in the aggregation unit 22 described above may be provided as an oxidizing agent to the oxidation unit 21 or as a neutralizing agent to the neutralization unit 60 . For this, a first supply pipe 22a and a second supply pipe 22b are connected to the aggregation unit 22, and sodium hydroxide (NaOH) is supplied to the oxidation unit 21 through the first supply pipe 22a or the second It may be supplied to the neutralization unit 60 through the supply pipe (22b). As sodium hydroxide (NaOH) generated in the coagulation unit 22 is used as an oxidizing agent or neutralizing agent, the amount of an oxidizing agent and a neutralizing agent required for the exhaust pollutant reduction process can be reduced, thereby reducing costs, and the device The configuration is also simplified, so space utilization in a narrow vessel can be increased. In the drawings, the first supply pipe 22a is illustrated as branching from the second supply pipe 22b, but the present invention is not limited thereto, and the first supply pipe 22a and the second supply pipe 22b are respectively connected to the aggregation unit 22 may be connected. When the first supply pipe 22a is branched from the second supply pipe 22b, a three-way valve is installed at the branching point of the first supply pipe 22a, so that the flow and the first supply pipe 22a side flow and The two supply pipe (22b) side flow can be controlled at the same time.

Hereinafter, with reference to FIG. 4 , the operation of the exhaust pollutant reducing device 1 will be described in more detail.

4 is an operation diagram for explaining the operation of the exhaust pollutant reducing device.

The exhaust pollutant reduction device 1 according to the present invention can effectively reduce carbon dioxide as well as sulfur oxides and nitrogen oxides contained in exhaust gas, so that it is possible to easily satisfy the strengthened regulations of the International Maritime Organization. In particular, since the heat generated when reducing carbon dioxide is recovered and provided to at least one of the selective catalytic reduction reactor 30 and the boiler 200, it is possible to save fuel as well as increase the device efficiency. In addition, since sodium hydroxide is used as an oxidizing agent for oxidizing carbon dioxide contained in the exhaust gas and as a neutralizing agent for neutralizing the acidified washing water by gas-liquid contact with the exhaust gas in the scrubber 50, the function as an oxidizing agent and the function as a neutralizing agent, respectively As well as being able to perform effectively, the device configuration is simplified, and the space utilization in a narrow vessel can be increased.

The exhaust gas discharged from the combustion engine 100 moves to the oxidation unit 21 along the exhaust pipe 10, and the oxidation unit 21 reacts the oxidizing agent with the exhaust gas to generate carbon dioxide (CO ₂ ) contained in the exhaust gas. oxidize In the initial state, an oxidizing agent may be injected into the oxidation unit 21 from the outside, and carbon dioxide (CO ₂ ) contained in the exhaust gas reacts with sodium hydroxide solution (NaOH) as an oxidizing agent to form a liquid carbon dioxide oxide (Na ₂ CO ₃ ) ) becomes The exhaust gas moves to the agglomeration unit 22 along the exhaust pipe 10 in a state containing carbon dioxide oxide (Na ₂ CO ₃ ), and the agglomeration unit 22 injects a coagulant into the exhaust gas to thereby inject carbon dioxide oxide (Na ₂ CO). ₃ ) to agglomerate. Carbon dioxide oxide (Na ₂ CO ₃ ) reacts with calcium hydroxide (Ca(OH) ₂ ), which is a coagulant, and causes a coagulation reaction. At this time, sodium hydroxide (NaOH) and calcium carbonate (CaCO ₃ ) are generated as by-products, and heat is generated. do. The generated heat is recovered through the first heat exchange tube 41 of the heat recovery unit 40 and transferred to the second heat exchange tube 42 and the third heat exchange tube 43 , respectively. The heat transferred to the second heat exchange tube 42 is used to thermally decompose urea water or increase the reaction temperature of exhaust gas, and the heat transferred to the third heat exchange tube 43 is used to increase the combustion temperature of fuel or steam used to create After carbon dioxide (CO ₂ ) is oxidized to carbon dioxide oxide (Na ₂ CO ₃ ) and aggregated into calcium carbonate (CaCO ₃ ), carbon dioxide contained in exhaust gas is removed, thereby satisfying regulations related to carbon dioxide. Since the aggregation unit 22 is formed as a three-phase separator, sodium hydroxide (NaOH) in a liquid state, calcium carbonate (CaCO ₃ ) in a solid state, and exhaust gas in a gaseous state are separated. The sodium hydroxide (NaOH) separated in the aggregation unit 22 is supplied to the oxidation unit 21 through the first supply pipe 22a or is supplied to the neutralization unit 60 through the second supply pipe 22b, and calcium carbonate ( CaCO ₃ ) can be stored in a separate tank.

The exhaust gas from which sodium hydroxide (NaOH) and calcium carbonate (CaCO ₃ ) are separated moves to the scrubber 50 along the exhaust pipe 10, and the scrubber 50 sprays washing water to the exhaust gas to obtain sulfur oxide (SOx) to remove As pollutants such as sulfur oxides and fine dust contained in exhaust gas are removed, regulations related to sulfur oxides can also be satisfied. The washing water acidified by dissolving sulfur oxides in the scrubber 50 moves to the neutralization unit 60 along the washing water discharge pipe 51 . The neutralization unit 60 neutralizes the washing water by injecting the neutralizing agent supplied through the second supply pipe 22b into the washing water supplied through the washing water discharge pipe 51, and the washing water neutralized to an appropriate pH is transferred to the washing water discharge pipe It may be circulated to the scrubber 50 along 51 or discharged to the sea.

The exhaust gas from which carbon dioxide, sulfur oxides, fine dust, etc. have been removed moves to the selective catalytic reduction reactor 30 along the exhaust pipe 10, and in the selective catalytic reduction reactor 30, urea water is thermally decomposed to form a catalyst layer with ammonia generated. The nitrogen oxides are reduced to nitrogen and water. Exhaust gas from which carbon dioxide, sulfur oxides, and nitrogen oxides have been removed through the above-described series of processes is discharged into the atmosphere through the exhaust pipe 10 .

Although embodiments of the present invention have been described above with reference to the accompanying drawings, those of ordinary skill in the art to which the present invention pertains can realize that the present invention can be embodied in other specific forms without changing its technical spirit or essential features. you will be able to understand Therefore, it should be understood that the embodiments described above are illustrative in all respects and not restrictive.

1: Exhaust pollutant reduction device
10: exhaust pipe 20: carbon dioxide reduction unit
21: oxidation unit 22: aggregation unit
22a: first supply pipe 22b: second supply pipe
30: selective catalytic reduction reactor 40: heat recovery unit
41: first heat exchange tube 42: second heat exchange tube
43: third heat exchange tube 50: scrubber
51: washing water discharge pipe 60: neutralization unit
100: combustion engine 200: boiler

Claims (6)

an exhaust pipe for discharging exhaust gas from the combustion engine;
a carbon dioxide reduction unit connected to the exhaust pipe and oxidizing and coagulating carbon dioxide contained in the exhaust gas to reduce the carbon dioxide concentration of the exhaust gas;
A selective catalytic reduction reactor connected to the exhaust pipe at the rear end of the carbon dioxide reduction unit to reduce nitrogen oxides contained in the exhaust gas, and
and a heat recovery unit that recovers heat generated from the carbon dioxide reduction unit and provides it to at least one of the selective catalytic reduction reactor and the boiler. According to claim 1, wherein the carbon dioxide reduction unit,
an oxidation unit for oxidizing the carbon dioxide by reacting the exhaust gas with an oxidizing agent;
and a coagulation unit disposed at the rear end of the oxidation unit and configured to aggregate the carbon dioxide oxide generated in the oxidation unit by injecting a coagulant into the exhaust gas,
The heat recovery unit is an exhaust pollutant reduction device for recovering heat by exchanging heat with at least one of the oxidation unit and the aggregation unit. 3. The method of claim 2,
The oxidation unit uses a sodium hydroxide (NaoH) solution as the oxidizing agent,
The coagulation unit uses calcium hydroxide (Ca(OH) ₂ ) as the coagulant,
The heat recovery unit is an exhaust pollutant reduction device for recovering heat generated during a coagulation reaction in the agglomeration unit. 3. The method of claim 2,
a scrubber connected to the exhaust pipe at the rear end of the coagulation unit and spraying washing water into the exhaust gas, and
Further comprising a neutralization unit connected to the washing water discharge pipe for discharging the washing water inside the scrubber and neutralizing the acidified washing water by injecting a neutralizing agent into the washing water,
An exhaust pollutant reduction device for providing sodium hydroxide generated in the coagulation unit as the oxidizing agent to the oxidation unit or as the neutralizing agent to the neutralization unit. According to claim 1, wherein the heat recovery unit,
At least one first heat exchange tube through which the high-temperature heat medium that has passed through the carbon dioxide reduction unit circulates;
It is disposed on one side of the first heat exchange tube and circulates a heat transfer fluid heated by heat exchange with the heating medium to the selective catalytic reduction reactor to heat at least one of the urea water and the exhaust gas supplied to the selective catalytic reduction reactor. Exhaust pollutant reduction device including a second heat exchange tube for transferring. The method of claim 5, wherein the heat recovery unit,
Further comprising a third heat exchange tube for transferring heat between the first heat exchange tube and the boiler,
The exhaust pollutant reduction device for the first heat exchange tube to exchange heat with the second heat exchange tube first and then with the third heat exchange tube.

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