KR20230047838A - Exhaust gas treatment apparatus - Google Patents

Abstract

According to one embodiment of the present invention, an exhaust gas treatment device is provided. According to one embodiment of the present invention, the exhaust gas treatment device comprises: an exhaust pipe discharging exhaust gas generated by a combustion engine; a carbon dioxide collection unit installed on the exhaust pipe to remove carbon dioxide contained in the exhaust gas; and a carbon dioxide liquefaction unit liquefying the carbon dioxide separated from the carbon dioxide collection unit. At least a portion of the liquefied carbon dioxide generated by the carbon dioxide liquefaction unit can be supplied to a suction pipe of the combustion engine.

Description

Exhaust gas treatment apparatus {Exhaust gas treatment apparatus}

The present invention relates to an exhaust gas treatment device, and more particularly, to an exhaust gas treatment device having a structure capable of efficiently utilizing carbon dioxide separated from exhaust gas.

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, unburned methane, and the like. As air pollution increases, regulations on various harmful substances included in exhaust gas are becoming stricter. Not only nitrogen oxides and sulfur oxides, but also carbon dioxide are subject to emission regulations from the International Maritime Organization (IMO), an organization affiliated with the United Nations. are receiving In fact, the International Maritime Organization is promoting a reduction of carbon dioxide emissions by 40% by 2030 and 70% by 2050 based on 2008.

Methods for capturing carbon dioxide contained in exhaust gas include a wet collection method using an absorbent and a dry collection method using a membrane, and the wet collection method is generally used. In the wet capture method, exhaust gas is passed through an absorption tower in which an absorbent is present, carbon dioxide contained in the exhaust gas is absorbed into the absorbent, and carbon dioxide and the absorbent are separated by passing the absorbent that has absorbed the carbon dioxide through a regeneration tower. In the prior art, carbon dioxide separated from a regeneration tower was simply compressed and stored, but was not efficiently utilized. Therefore, an exhaust gas treatment device having a structure that more efficiently utilizes the separated carbon dioxide has been required.

Republic of Korea Patent No. 10-1834488 (2018. 02. 26.)

A technical problem to be achieved by the present invention is to provide an exhaust gas treatment device having a structure capable of efficiently utilizing carbon dioxide separated from exhaust gas.

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.

An exhaust gas treatment device according to an embodiment of the present invention for achieving the above technical problem is an exhaust pipe through which exhaust gas generated in a combustion engine is discharged, and carbon dioxide installed on the exhaust pipe to remove carbon dioxide contained in the exhaust gas. A collection unit and a carbon dioxide liquefaction unit for liquefying the carbon dioxide separated from the carbon dioxide capture unit, wherein at least a portion of the liquefied carbon dioxide generated in the carbon dioxide liquefaction unit is supplied to the intake pipe of the combustion engine.

The liquefied carbon dioxide may be vaporized before being supplied to the intake pipe, and gaseous carbon dioxide may be supplied to the combustion engine.

The carbon dioxide collecting unit includes an absorption unit for injecting an absorbent into the exhaust gas, a regeneration unit receiving the absorbent in which carbon dioxide is absorbed from the absorption unit and separating carbon dioxide from the absorbent, and circulating from the regeneration unit to the absorption unit. and an intercooler for cooling the absorbent from which carbon dioxide is separated by heat exchange with the liquefied carbon dioxide supplied to the intake pipe.

The carbon dioxide capturing unit further includes a circulation pipe in which a refrigerant exchanging heat with the absorbent circulates through the intercooler in a closed loop independent cycle, and an auxiliary intercooler for exchanging heat between the refrigerant and the liquefied carbon dioxide. The liquefied carbon dioxide passing through the intercooler may be vaporized and supplied to the combustion engine.

The exhaust gas treatment device further includes a storage tank installed at a rear end of the carbon dioxide liquefaction unit to store the liquefied carbon dioxide, wherein at least one of the liquefied carbon dioxide stored in the storage tank and the carbon dioxide vaporized from the liquefied carbon dioxide is stored in the liquefied carbon dioxide. It can be supplied as an auxiliary intercooler.

According to the present invention, since the carbon dioxide separated from the exhaust gas is supplied to the intake pipe of the combustion engine, the methane number of the fuel is controlled and the combustion temperature is lowered, thereby reducing the amount of nitrogen oxides contained in the exhaust gas. Accordingly, facilities such as a selective catalytic reduction reactor and a urea water tank may be omitted, and thus, maintenance costs may be reduced and utilization of space in a ship may be increased.

In addition, since the absorbent is cooled using the cooling heat of liquefied carbon dioxide, energy consumed for cooling the absorbent can be reduced, enabling efficient operation of the device.

1 is a diagram schematically showing an exhaust gas treatment device according to an embodiment of the present invention.
2 is an operation diagram for explaining the operation of the exhaust gas treatment device.

Advantages and features of the present invention, and methods of achieving them, will become clear with reference to the detailed description of the following embodiments taken 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 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.

Hereinafter, with reference to FIGS. 1 and 2, an exhaust gas treatment device according to an embodiment of the present invention will be described in detail.

An exhaust gas treatment device according to an embodiment of the present invention is a device that reduces the concentration of carbon dioxide contained in exhaust gas generated by combustion of fuel in a combustion engine, and is installed on a ship to treat exhaust gas generated in shipbuilding and marine fields. can be used to

Since the exhaust gas treatment device supplies carbon dioxide separated from the exhaust gas to the intake pipe of the combustion engine, the methane number of the fuel is adjusted and the combustion temperature is lowered, thereby reducing the amount of nitrogen oxides included in the exhaust gas. Accordingly, facilities such as a selective catalytic reduction reactor and a urea water tank may be omitted, and thus, maintenance costs may be reduced and utilization of space in a ship may be increased. In addition, since the absorbent is cooled using the cooling heat of liquefied carbon dioxide, energy consumed for cooling the absorbent can be reduced, thereby enabling efficient operation of the apparatus.

Hereinafter, with reference to FIG. 1 , the exhaust gas treatment device 1 will be described in detail.

1 is a diagram schematically showing an exhaust gas treatment device according to an embodiment of the present invention.

An exhaust gas treatment device 1 according to the present invention includes an exhaust pipe 10, a carbon dioxide capture unit 20, and a carbon dioxide liquefaction unit 30.

The exhaust pipe 10 is a pipe through which exhaust gas generated in the combustion engine 100 is discharged, and one end is connected to the combustion engine 100 and the other end is connected to a communication (not shown). Since the combustion engine 100 generates power by burning fuel, exhaust gas is generated according to the combustion of the fuel, and the generated exhaust gas is discharged through the exhaust pipe 10 . A carbon dioxide collecting unit 20 is installed on the exhaust pipe 10 .

The carbon dioxide collecting unit 20 removes carbon dioxide contained in exhaust gas, and includes an absorption unit 21, a regeneration unit 22, and an intercooler 23.

The absorption unit 21 atomizes or atomizes an absorbent for absorbing carbon dioxide into the exhaust gas supplied through the exhaust pipe 10 and sprays it. Here, the absorbent refers to absorbing carbon dioxide. It may be a solution having the property of reducing, for example, an amine compound or an aqueous solution of ammonia. The absorption unit 21 may be formed as a gas contact type absorption tower to easily cope with ship rocking, but is not limited thereto, and various methods may be applied. The exhaust gas is supplied to the lower part of the absorbing part 21 and contacts the absorbent sprayed from the upper part of the absorbing part 21. As a result, carbon dioxide contained in the exhaust gas is absorbed by the absorbent and can be removed from the exhaust gas. Exhaust gas from which carbon dioxide has been removed is discharged to the outside through the upper part of the absorbing part 21. Since an exothermic reaction occurs when carbon dioxide is absorbed into the absorbent, it can be discharged after a separate cooling process at the upper part of the absorbing part 21. there is. For example, the exhaust gas may be cooled in gas-liquid contact with a cooling medium such as fresh water sprayed from the top of the absorber 21 and then discharged, and the cooling medium in contact with the exhaust gas is collected and discharged outside the absorber 21. After being discharged, it may be circulated back to the absorption unit 21 through pressurization and cooling processes. The absorbent that has absorbed carbon dioxide in the absorption unit 21 is supplied to the regeneration unit 22 along the supply line 21a.

The supply line 21a has one end connected to the lower part of the absorbing part 21 and the other end connected to the upper part of the regenerating part 22, so that the absorbent absorbing the carbon dioxide discharged from the absorbing part 21 is transferred to the upper part of the regenerating part 22. can supply A pump 21b for pressurizing an absorbent for absorbing carbon dioxide and a heat exchanger 21c for exchanging heat between the supply line 21a and a second circulation line 22b to be described below may be installed on the supply line 21a. The heat exchanger 21c heats the absorbent that has absorbed the carbon dioxide at about 40 to 50° C. discharged from the absorption unit 21 with the absorbent from which the carbon dioxide at about 80 to 150° C. discharged from the regeneration unit 22 is separated and heat exchanged. do. That is, the heat exchanger 21c includes the absorbent supplied from the absorption unit 21 to the regeneration unit 22 through the supply line 21a, and the absorption unit from the regeneration unit 22 through the second circulation line 22b. The absorbent circulated to 21) is heat-exchanged to increase the temperature of the absorbent supplied to the regeneration unit 22 and lower the temperature of the absorbent circulated to the absorption unit 21. Accordingly, carbon dioxide can be easily absorbed into the absorbent in the absorption section 21, and carbon dioxide can be easily separated from the absorbent in the regeneration section 22. The absorbent absorbing the carbon dioxide heated in the heat exchanger 21c may be introduced into the upper part of the regeneration unit 22 .

The regeneration unit 22 receives the absorbent in which carbon dioxide is absorbed from the absorption unit 21 and separates carbon dioxide from the absorbent. More specifically, the absorbent absorbing the carbon dioxide supplied to the top of the regeneration unit 22 after being heated in the heat exchanger 21c flows from the top to the bottom of the regeneration unit 22, and carbon dioxide is separated by thermal energy. At this time, some of the absorbent in the regenerator 22 flows into the reboiler 26 through the first circulation line 22a and is heated, and carbon dioxide and steam generated from the absorbent by heating the reboiler 26 It is supplied to the regeneration unit 22 through the first circulation line 22a to provide additional thermal energy while increasing the efficiency of carbon dioxide separation. As described above, since the absorbent supplied to the regeneration unit 22 is heated in the heat exchanger 21c and the carbon dioxide and steam generated from the absorbent heated in the reboiler 26 additionally provide thermal energy, carbon dioxide can be easily separated from the absorbent. The high-concentration carbon dioxide separated from the absorbent is discharged to the upper part of the regeneration unit 22 and passes through the condenser 22c and the reflux drum 22d in order to remove moisture, and the water separated from the carbon dioxide is pressurized and returned to the regeneration unit 22 can be cycled through

The above-described second circulation line 22b circulates the absorbent discharged from the regeneration unit 22 to the absorption unit 21, and the above-described heat exchanger 21c and the pump 221 are installed on the second circulation line 22b. , and the intercooler 23 may be installed. The absorbent from which carbon dioxide at about 80 to 150 ° C. is separated from the carbon dioxide discharged from the regeneration unit 22 and flowing through the second circulation line 22b exchanges heat with the absorbent flowing through the supply line 21a in the heat exchanger 21c to be first It is cooled, and after being pressurized by the pump 221, it is secondarily cooled by the intercooler 23 and supplied to the absorption unit 21 at about 30 to 50 °C. The intercooler 23 will be described later in more detail.

On the other hand, the carbon dioxide discharged from the reflux drum 22d is supplied to the carbon dioxide liquefaction unit 30 and liquefied, and at least some of the liquefied carbon dioxide generated in the carbon dioxide liquefaction unit 30 is supplied to the intake pipe 110 of the combustion engine 100 supplied with At this time, the liquefied carbon dioxide may be vaporized before being supplied to the intake pipe 110, and thus gaseous carbon dioxide may be supplied to the combustion engine 100. As the liquefied carbon dioxide generated in the carbon dioxide liquefaction unit 30 is vaporized and supplied to the intake pipe 110, the methane number of the fuel is adjusted and the combustion temperature is lowered, thereby reducing the amount of nitrogen oxides included in the exhaust gas. As the amount of nitrogen oxides contained in the exhaust gas is reduced, equipment such as a selective catalytic reduction reactor and a urea water tank can be omitted, thereby reducing maintenance costs and increasing the utilization of space in the ship. there is.

The liquefied carbon dioxide generated in the carbon dioxide liquefaction unit 30 is stored in the storage tank 40 installed at the rear end of the carbon dioxide liquefaction unit 30, and at least one of the liquefied carbon dioxide stored in the storage tank 40 and the carbon dioxide vaporized from the liquefied carbon dioxide If necessary, cold heat may be transferred to the intercooler 23 and then supplied to the intake pipe 110 . Since at least one of liquefied carbon dioxide and carbon dioxide vaporized from liquefied carbon dioxide transfers cold heat to the intercooler 23, energy consumed for cooling the absorbent can be reduced, thereby increasing device efficiency. More specifically, the intercooler 23 may cool the absorbent from which carbon dioxide circulated from the regeneration unit 22 to the absorption unit 21 is separated by heat exchange with liquefied carbon dioxide supplied to the intake pipe 110, directly or indirectly. there is. Hereinafter, a structure in which the intercooler 23 indirectly exchanges heat between the absorbent and the liquefied carbon dioxide will be more intensively described. A circulation pipe 24 passes through the intercooler 23, and the circulation pipe 24 configures a closed loop independent cycle so that a refrigerant exchanging heat with an absorbent can circulate. That is, the intercooler 23 cools the absorbent by exchanging heat between the absorbent from which carbon dioxide is separated flowing through the second circulation line 22b and the refrigerant flowing through the circulation pipe 24. The circulation pipe 24 passes through the auxiliary intercooler 25, and the auxiliary intercooler 25 exchanges heat with at least one of liquefied carbon dioxide or vaporized carbon dioxide supplied from the storage tank 40 and the refrigerant, so that heat is exchanged with the absorbent and heated The refrigerant can be cooled again. When the liquefied carbon dioxide and the refrigerant exchange heat in the auxiliary intercooler 25, the liquefied carbon dioxide may lose cold heat and be vaporized, and when the vaporized carbon dioxide and the refrigerant exchange heat, the temperature of the carbon dioxide may rise. The liquefied carbon dioxide stored in the storage tank 40 flows along the first flow pipe 41, and the carbon dioxide vaporized from the liquefied carbon dioxide stored in the storage tank 40 flows along the second flow pipe 42, and the first flow pipe ( 41) and the second flow pipe 42 may join the joining pipe 43. Since the confluence pipe 43 passes through the auxiliary intercooler 25 and is connected to the intake pipe 110 , the liquefied carbon dioxide passing through the auxiliary intercooler 25 may be vaporized and supplied to the combustion engine 100 .

Hereinafter, with reference to FIG. 2, the operation of the exhaust gas treatment device 1 will be described in more detail.

2 is an operation diagram for explaining the operation of the exhaust gas treatment device.

Since the exhaust gas treatment device 1 according to the present invention supplies carbon dioxide separated from exhaust gas to the intake pipe 110 of the combustion engine 100, the methane number of the fuel is adjusted and the combustion temperature is lowered, thereby reducing nitrogen contained in the exhaust gas. The amount of oxide can be reduced. Accordingly, facilities such as a selective catalytic reduction reactor and a urea water tank may be omitted, and thus, maintenance costs may be reduced and utilization of space in a ship may be increased. In addition, since the absorbent is cooled using the cooling heat of liquefied carbon dioxide, energy consumed for cooling the absorbent can be reduced, enabling efficient operation of the device.

The exhaust gas generated in the combustion engine 100 is supplied to the absorbing part 21 of the carbon dioxide collecting unit 20 through the exhaust pipe 10 and comes into gas-liquid contact with the absorbent, whereby the carbon dioxide contained in the exhaust gas is absorbed into the absorbent. Absorbed. The exhaust gas from which carbon dioxide is removed is discharged to the outside after a separate cooling process at the top of the absorption unit 21, and the absorbent absorbing carbon dioxide is discharged through the supply line 21a. The absorbent absorbing the carbon dioxide discharged through the supply line 21a is pressurized by the pump 21b and then heated by exchanging heat with the absorbent circulated to the absorber 21 through the second circulation line 22b in the heat exchanger 21c. After being supplied to the regeneration unit (22). The absorbent that absorbs the carbon dioxide supplied to the regeneration unit 22 is separated from carbon dioxide by thermal energy flowing from the top to the bottom of the regeneration unit 22, and some of the absorbent from which the carbon dioxide is separated passes through the first circulation line 22a. After being introduced into the reboiler 26 and heated, it is supplied to the regeneration unit 22 again. The remaining part of the absorbent from which carbon dioxide is separated passes through the heat exchanger 21c through the second circulation line 22b, is cooled in multiple stages through the intercooler 23, and then supplied to the absorption unit 21.

On the other hand, the high-concentration carbon dioxide separated from the absorbent is discharged to the upper part of the regeneration unit 22, and after moisture is removed, it moves to the carbon dioxide liquefaction unit 30 and is liquefied. The liquefied carbon dioxide generated in the carbon dioxide liquefaction unit 30 is stored in the storage tank 40, and the liquefied carbon dioxide or vaporized carbon dioxide stored in the storage tank 40 is stored in the first flow pipe 41 or the second flow pipe 42 when necessary. Flows through the confluence pipe 43 and is supplied to the auxiliary intercooler 25. The auxiliary intercooler 25 exchanges heat between liquefied carbon dioxide or vaporized carbon dioxide flowing through the confluence pipe 43 and the refrigerant flowing through the circulation pipe 24, and the refrigerant cooled in the intercooler 23 passes through the circulation pipe 24. It moves to the intercooler 23 along the way and transfers cold heat to the absorbent. The liquefied carbon dioxide or vaporized carbon dioxide that has exchanged heat with the refrigerant in the intercooler 23 moves along the confluence pipe 43 in a vaporized or elevated temperature state and is supplied to the intake pipe 110 . Outside air and carbon dioxide supplied to the combustion engine 100 serve to control the methane number of the fuel and lower the combustion temperature, and as a result, the amount of nitrogen oxides contained in the exhaust gas can be reduced.

Although the embodiments of the present invention have been described with reference to the accompanying drawings, those skilled in the art to which the present invention pertains can be implemented in other specific forms without changing the technical spirit or essential features of the present invention. you will be able to understand Therefore, the embodiments described above should be understood as illustrative in all respects and not limiting.

1: Exhaust gas treatment device
10: exhaust pipe 20: carbon dioxide collecting unit
21: absorption unit 22: regeneration unit
23: intercooler 24: circulation pipe
25: auxiliary intercooler 26: reboiler
30: carbon dioxide liquefaction unit 40: storage tank
41: first flow pipe 42: second flow pipe
43: confluence pipe
100: combustion engine 110: intake pipe

Claims (5)

Exhaust pipe through which the exhaust gas generated in the combustion engine is discharged;
A carbon dioxide collecting unit installed on the exhaust pipe to remove carbon dioxide contained in the exhaust gas, and
Including a carbon dioxide liquefaction unit for liquefying the carbon dioxide separated from the carbon dioxide capturing unit,
At least a part of the liquefied carbon dioxide generated in the carbon dioxide liquefaction unit is supplied to the intake pipe of the combustion engine. According to claim 1,
The liquefied carbon dioxide is vaporized before being supplied to the intake pipe, and gaseous carbon dioxide is supplied to the combustion engine. The method of claim 2, wherein the carbon dioxide collecting unit,
an absorption unit for injecting an absorbent into the exhaust gas;
A regeneration unit receiving the absorbent in which carbon dioxide is absorbed from the absorber and separating carbon dioxide from the absorbent; and
and an intercooler configured to cool the absorbent from which carbon dioxide circulated from the regeneration unit to the absorption unit is separated by exchanging heat with the liquefied carbon dioxide supplied to the intake pipe. According to claim 3,
A circulation pipe through which a refrigerant that exchanges heat with the absorber circulates through the intercooler by configuring a closed loop independent cycle, and
Further comprising an auxiliary intercooler for exchanging heat between the refrigerant and the liquefied carbon dioxide,
An exhaust gas treatment device in which the liquefied carbon dioxide passing through the auxiliary intercooler is vaporized and supplied to the combustion engine. According to claim 4,
Further comprising a storage tank installed at the rear end of the carbon dioxide liquefaction unit to store the liquefied carbon dioxide,
At least one of the liquefied carbon dioxide stored in the storage tank and the carbon dioxide vaporized from the liquefied carbon dioxide is supplied to the auxiliary intercooler.

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