Carbon dioxide separation and collection system

Abstract

The present invention relates to a carbon dioxide separation and collection system. The carbon dioxide separation and collection system according to an embodiment of the present invention comprises: a compression unit that is supplied with exhaust gas and compresses same; a first cooling unit, connected to the compression unit, for pre-cooling the compressed gas compressed by the compression unit; a second cooling unit, connected to the first cooling unit, for re-cooling the pre-cooled compressed gas pre-cooled in the first cooling unit; a phase change induction unit, connected to the second cooling unit, for isentropically expanding the re-cooled compressed gas re-cooled in the second cooling unit, thereby inducing the carbon dioxide in a gaseous state contained in the re-cooled compressed gas to undergo a phase change to a solid state; a separation unit, connected to the phase change induction unit, for separating solid carbon dioxide and the remaining gases from the expansion gas isentropically expanded in the phase change induction unit; and a third cooling unit that is connected to the separation unit, is supplied with the remaining gases from the separation unit, cools the remaining gases, and supplies the cooled gases to the second cooling unit.

Description

Carbon dioxide separation and capture system

[0001] The present invention relates to a carbon dioxide separation and capture system.

[0002] As global warming accelerates, problems such as abnormal temperatures and rising sea levels are occurring worldwide. The primary cause of this worsening global warming is the increase in greenhouse gas emissions, with carbon dioxide accounting for the largest proportion of all greenhouse gases. Consequently, the need to reduce carbon dioxide emissions is growing.

[0003] However, given that industrial energy efficiency is currently at its peak, excessive reductions in carbon dioxide emissions could weaken industrial competitiveness. Therefore, in addition to efforts to reduce carbon dioxide emissions, direct reductions through carbon capture, utilization, and storage (CCUS, hereinafter referred to as "CCUS") are increasingly sought as a technological alternative.

[0004] Carbon dioxide capture / storage / utilization technology includes technologies for capturing carbon dioxide generated from industrial facilities, storing the captured carbon dioxide underground, and converting carbon dioxide into useful resources with high added value.

[0005] Among these, carbon dioxide capture technology is broadly divided into post-combustion technology, pre-combustion technology, and oxy-fuel combustion technology.

[0006] Specifically, post-combustion capture technology is a method of separating carbon dioxide from exhaust gases emitted when burning fossil fuels with air, pre-combustion capture technology is a method of separating carbon dioxide in the process of producing hydrogen from fossil fuels, converting the synthesis gas generated after gasifying fossil fuels into carbon dioxide and hydrogen through the water gas shift reaction, and then separating only carbon dioxide, and oxy-combustion technology is a method of separating only carbon dioxide after combustion by separating oxygen in the air instead of air and combusting fossil fuels.

[0007] Among these, post-combustion capture technologies are classified into wet absorption methods using amine-based wet absorbents, dry absorption methods using solid absorbents, membrane separation methods using membranes, and phase separation methods using phase change.

[0008] However, in the case of the wet absorption method, there is a problem that the compression work required to liquefy the carbon dioxide separated from the wet absorbent after separating carbon dioxide from the wet absorbent is large, and a high energy is required to regenerate the wet absorbent to its initial state. The dry absorption method also has a problem that the compression work required to liquefy the carbon dioxide separated from the solid absorbent after separating carbon dioxide from the solid absorbent is large, and a high energy is required to regenerate the solid absorbent to its initial state. In addition, in the case of the membrane separation method, there is a problem that it is difficult to increase the capacity, and the durability is weak due to deterioration of the separation membrane. In addition, in the case of the phase separation method, there is a disadvantage that it shows low energy efficiency because a pressure higher than the triple point is required to separate carbon dioxide from the exhaust gas into a liquid.

[0009] Meanwhile, to improve these issues, cryogenic carbon capture processes have been proposed. Cryogenic carbon capture processes can be categorized into direct cooling, which freezes carbon dioxide in exhaust gas through a process of compressing, cooling, and expanding the exhaust gas, and indirect cooling, which freezes carbon dioxide in the exhaust gas using the cold energy of liquefied natural gas or a refrigerator.

[0010] However, in the case of conventional direct cooling methods, the compressed / cooled exhaust gas is expanded using a Joule-Thomson valve or an expander. However, in the case of a Joule-Thomson valve, since the temperature reduction according to the expansion ratio is not large, a high compression ratio is required, which causes a problem in that a relatively large amount of energy is consumed. In addition, in the case of an expander, there is a problem that the technical implementation is difficult because the separated carbon dioxide in a solid form impacts the high-speed rotating impeller.

[0011] In addition, in the case of conventional indirect cooling methods, cold energy is essential, and if external cold energy is not supplied stably, a refrigerator must be used, which causes a problem of rapid increase in energy consumption.

[0012] Therefore, there is a need for the development of a technology that can efficiently freeze carbon dioxide contained in exhaust gas by isentropically expanding compressed / cooled exhaust gas and reuse the cold energy of the frozen carbon dioxide in the carbon dioxide separation and capture process, thereby minimizing energy consumption and increasing energy efficiency.

[0013] Embodiments of the present invention have been devised to solve the above-described conventional problems, and to provide a carbon dioxide separation and capture system capable of efficiently freezing carbon dioxide contained in exhaust gas by isentropically expanding compressed / cooled exhaust gas, and reusing the cold energy of the frozen carbon dioxide in the carbon dioxide separation and capture process, thereby minimizing energy consumption and increasing energy efficiency.

[0014] According to one aspect of the present invention, a carbon dioxide separation and capture system may be provided, including: a compression unit that receives exhaust gas and compresses it; a first cooling unit connected to the compression unit and precools the compressed gas compressed in the compression unit; a second cooling unit connected to the first cooling unit and recools the precooled compressed gas precooled in the first cooling unit; a phase change inducing unit connected to the second cooling unit and isentropically expanding the recooled compressed gas recooled in the second cooling unit to induce a phase change of gaseous carbon dioxide contained in the recooled compressed gas into a solid state; a separation unit connected to the phase change inducing unit and separating the expanded gas isentropically expanded in the phase change inducing unit into solid carbon dioxide and a remaining gas; and a third cooling unit connected to the separation unit and receiving the remaining gas from the separation unit, cooling the remaining gas, and supplying it to the second cooling unit.

[0015] In addition, the first cooling unit includes a tank connected to the separation unit and containing the solid carbon dioxide supplied from the separation unit therein; and a pipe connecting between the compression unit and the second cooling unit, at least a portion of which is disposed on either the inside or the outside of the tank, and the compressed gas flowing through the pipe disposed on either the inside or the outside of the tank can receive the cooling heat of the solid carbon dioxide contained in the tank.

[0016] In addition, the pipe may include an inlet part connected to the compression part and into which the compressed gas is introduced; a discharge part connected to the second cooling part and into which the pre-cooled compressed gas is discharged; and a heat exchange part connecting between the inlet part and the discharge part and disposed either inside or outside the tank.

[0017] Additionally, the third cooling unit may include an expander connected to the separation unit to expand and cool the remaining gas separated by the separation unit.

[0018] In addition, the second cooling unit includes a pre-cooled compressed gas path that provides a flow path of the pre-cooled compressed gas pre-cooled in the first cooling unit; and a cooled residual gas path that provides a flow path of the cooled residual gas expanded and cooled in the expander, and the pre-cooled compressed gas flowing in the pre-cooled compressed gas path can be cooled by receiving cooling heat from the cooled residual gas flowing in the cooled residual gas path and then supplied to the phase change induction unit.

[0019] In addition, the second cooling unit further includes a liquefied natural gas path that provides a flow path for liquefied natural gas supplied from a liquefied natural gas supply source, and the liquefied natural gas flowing in the liquefied natural gas path can be vaporized by receiving heat from the remaining cooled gas flowing in the remaining cooled gas path.

[0020] In addition, the third cooling unit includes a compander expander connected to the separation unit, which receives the remaining gas from the separation unit and expands and cools the remaining gas; and a compander compressor connected axially to the compander expander, wherein the compander compressor can compress the recooled compressed gas discharged from the second cooling unit using energy recovered from the compander expander and supply the compressed recooled compressed gas to the phase change induction unit.

[0021] In addition, the system further includes a vaporization unit provided between the separation unit and the third cooling unit, and the vaporization unit can receive the remaining gas discharged from the separation unit and supply the heat of the remaining gas to the liquefied natural gas to induce vaporization of the liquefied natural gas.

[0022] In addition, the first cooled remaining gas cooled by transferring heat to the liquefied natural gas through the vaporization unit may be supplied to the third cooling unit and cooled, and the second cooled remaining gas cooled in the third cooling unit may be supplied to the second cooling unit.

[0023] In addition, the present invention further includes a pre-cooling compressed gas compressor provided between the first cooling unit and the second cooling unit, and the pre-cooling compressed gas compressor can compress the pre-cooling compressed gas by receiving power generated from the expander.

[0024] In addition, the system further includes a vaporization unit that is provided between the separation unit and the expander and induces vaporization of the liquefied natural gas by using the heat of the remaining gas discharged from the separation unit, and the cooled remaining gas that is cooled by transferring heat to the liquefied natural gas through the vaporization unit can be supplied to the expander and expanded, thereby being cooled again.

[0025] According to embodiments of the present invention, carbon dioxide contained in the exhaust gas can be efficiently frozen by isentropically expanding the compressed / cooled exhaust gas, and the cold heat of the frozen carbon dioxide can be reused in the carbon dioxide separation and capture process, thereby minimizing energy consumption and increasing energy efficiency.

[0026] FIG. 1 is a block diagram illustrating a carbon dioxide separation and capture system according to one embodiment of the present invention.

[0027] Figure 2 is a process diagram illustrating the carbon dioxide separation and capture system of Figure 1.

[0028] Figure 3 is a conceptual diagram illustrating an example of the first cooling unit of the carbon dioxide separation and capture system of Figure 1.

[0029] Figure 4 is a conceptual diagram illustrating a modified example of the first cooling unit of the carbon dioxide separation and capture system of Figure 1.

[0030] Figure 5 is a process diagram illustrating a carbon dioxide separation and capture system according to another embodiment of the present invention.

[0031] Figure 6 is a process diagram illustrating a carbon dioxide separation and capture system according to another embodiment of the present invention.

[0032] Figure 7 is a process diagram illustrating a carbon dioxide separation and capture system according to another embodiment of the present invention.

[0033] FIG. 8 is a block diagram illustrating a carbon dioxide separation and capture system according to another embodiment of the present invention.

[0034] Figure 9 is a process diagram illustrating the carbon dioxide separation and capture system of Figure 8.

[0035] Figure 10 is a process diagram illustrating a carbon dioxide separation and capture system according to another embodiment of the present invention.

[0036] Figure 11 is a process diagram illustrating a carbon dioxide separation and capture system according to another embodiment of the present invention.

[0037] Figure 12 is a process diagram illustrating a carbon dioxide separation and capture system according to another embodiment of the present invention.

[0038] Figure 13 is a process diagram illustrating a carbon dioxide separation and capture system according to another embodiment of the present invention.

[0039] Hereinafter, specific embodiments for implementing the idea of ​​the present invention will be described in detail with reference to the drawings.

[0040] In addition, when explaining the present invention, if it is determined that a detailed description of a related known configuration or function may obscure the gist of the present invention, the detailed description is omitted.

[0041] Additionally, when it is said that a component is 'coupled' or 'connected' to another component, it should be understood that it may be directly coupled or connected to that other component, but there may also be other components present in between.

[0042] The terminology used herein is intended solely to describe specific embodiments and is not intended to limit the invention. Singular expressions include plural expressions unless the context clearly dictates otherwise.

[0043] Furthermore, the expressions "one side," "the other side," "upper side," and "lower side" in this specification are based on the drawings and may be expressed differently if the orientation of the object changes. For the same reason, some components in the attached drawings are exaggerated, omitted, or schematically depicted, and the size of each component does not fully reflect the actual size.

[0044] Additionally, terms that include ordinal numbers, such as "first," "second," etc., may be used to describe various components, but these components are not limited by such terms. These terms are used solely to distinguish one component from another.

[0045] The term "comprising" as used in the specification means specifying a particular characteristic, region, integer, step, operation, element and / or component, but does not exclude the presence or addition of other particular characteristics, regions, integers, steps, operations, elements, components and / or groups.

[0046] Hereinafter, a specific configuration of a carbon dioxide separation and capture system according to one embodiment of the present invention will be described with reference to the drawings.

[0047] Referring to FIGS. 1 to 4, a carbon dioxide separation and capture system (1) according to one embodiment of the present invention may include a compression unit (10), a first cooling unit (20), a second cooling unit (30), a phase change induction unit (40), a separation unit (50), and a third cooling unit (60).

[0048] The compression unit (10) can receive exhaust gas from an exhaust gas supply source (2) and compress it. For example, the exhaust gas may be flue gas composed of nitrogen, oxygen, carbon dioxide, and water vapor discharged from an exhaust gas supply source (2), such as an engine. However, this is merely an example for convenience of explanation, and the composition of the exhaust gas may vary to various compositions containing at least carbon dioxide.

[0049] The compression unit (10) can compress the pre-processed gas to separate and remove combustion products contained in the exhaust gas to a predetermined pressure, for example, about 3.5 bar to about 6 bar, and the gas compressed in the compression unit (10) (hereinafter referred to as “compressed gas”) can be post-processed and then supplied to the first cooling unit (20). Here, post-processing means removing moisture contained in the compressed gas.

[0050] The first cooling unit (20) can precool the compressed gas compressed in the compression unit (10). To this end, the first cooling unit (20) can be connected to the rear end of the compression unit (10), and can precool the compressed gas by heat-exchanging the compressed gas discharged from the compression unit (10) with the solid carbon dioxide discharged from the separation unit (50). Hereinafter, for the convenience of explanation, the compressed gas precooled through the first cooling unit (20) will be referred to as precooled compressed gas.

[0051] The first cooling unit (20) is connected to the separation unit (50), and may include a tank (21) in which solid carbon dioxide supplied from the separation unit (50) is contained, and a pipe (22) connecting between the compression unit (10) and the second cooling unit (30), at least a portion of which is disposed on either the inside or the outside of the tank (21).

[0052] The tank (21) may have a dual structure consisting of an outer tank (211) and an inner tank (212). The inner tank (212) is a portion where the solid carbon dioxide separated from the separation unit (50) is actually received, and may be provided with a receiving space (2123) in which the solid carbon dioxide can be received. Solid carbon dioxide can be introduced through the inner tank inlet (2121) of the inner tank (212), and liquid carbon dioxide can be discharged through the inner tank outlet (2122) of the inner tank (212). This will be described later.

[0053] The outer shell (211) can be arranged on the outside of the inner shell (212) to protect the inner shell (212). For example, the inner surface of the outer shell (211) can be arranged to be spaced apart from the outer surface of the inner shell (212), thereby forming a predetermined space (2113) between the inner surface of the outer shell (211) and the outer surface of the inner shell (212).

[0054] The pipe (22) can provide a flow path of compressed gas provided from the compression unit (10), and can be divided into an inlet part (221), a heat exchange part (222), and a discharge part (223).

[0055] The inlet part (221) is connected to the compression part (10) and is a part through which compressed gas is introduced from the compression part (10). It can be arranged to pass through the outer inlet port (2111) of the outer tank (211), and the end of the inlet part (221) connected to the heat exchange part (222) can be arranged in the receiving space (2123) of the inner tank (212) by penetrating the inner tank (212).

[0056] The discharge part (223) is a part where the pre-cooled compressed gas that has been pre-cooled by heat exchange with solid carbon dioxide in the heat exchange part (222) is discharged, and the end of the discharge part (223) connected to the heat exchange part (222) can be arranged to pass through the inner tank (212) and the outer tank discharge port (2112) of the outer tank (211).

[0057] The heat exchange part (222) can be placed in the receiving space (2123) of the inner tank (212) to connect the inlet part (221) and the discharge part (223). In other words, the compressed gas introduced into the inlet part (221) is precooled while passing through the heat exchange part (222), and the precooled compressed gas can be discharged through the discharge part (223).

[0058] To this end, the heat exchange part (222) can connect the inlet part (221) and the discharge part (223) with multiple paths for heat exchange efficiency between the compressed gas and the solid carbon dioxide. In other words, multiple heat exchange parts (222) can be provided between the inlet part (221) and the discharge part (223). Accordingly, the compressed gas flowing inside the multiple heat exchange parts (222) exchanges heat with the cold heat of the solid carbon dioxide outside the multiple heat exchange parts (222), so that the compressed gas and the solid carbon dioxide can exchange heat with each other without direct contact.

[0059] The pre-cooled compressed gas that has been cooled by receiving the cold heat of the solid carbon dioxide can be supplied to the second cooling unit (30), and the solid carbon dioxide that has transferred the cold heat to the compressed gas can be liquefied. The liquefied solid carbon dioxide (hereinafter referred to as “liquid carbon dioxide”) can be transported to and stored in a liquid carbon dioxide storage tank (25).

[0060] The second cooling unit (30) can re-cool the pre-cooled compressed gas pre-cooled in the first cooling unit (20). For convenience of explanation, the compressed gas re-cooled through the second cooling unit (30) is referred to as re-cooled compressed gas in the following description.

[0061] To this end, the second cooling unit (30) may be connected to the compression unit (10) and may include a pre-cooled compressed gas passage (31) that provides a flow path of the pre-cooled compressed gas pre-cooled in the first cooling unit (20) and a cooled residual gas passage (32) that provides a flow path of the cooled residual gas expanded and cooled in the expander (61) of the third cooling unit (60) to be described later.

[0062] The pre-cooled compressed gas flowing in the pre-cooled compressed gas path (31) can be cooled by receiving the cooling heat of the cooled remaining gas flowing in the cooled remaining gas path (32) and then supplied to the phase change induction unit (40).

[0063] The phase change induction unit (40) can induce the re-cooled compressed gas re-cooled in the second cooling unit (30) to undergo isentropic expansion, thereby inducing the gaseous carbon dioxide contained in the re-cooled compressed gas to undergo a phase change into a solid state. For convenience of explanation, the re-cooled compressed gas isentropically expanded by the phase change induction unit (40) will be referred to as expanded gas in the following description.

[0064] To this end, the phase change inducing unit (40) may include an isentropic nozzle (41) connected to the second cooling unit (30). The isentropic nozzle (41) can induce the phase change of the gaseous carbon dioxide contained in the recooled compressed gas into a solid state and be separated by converting the flow of the recooled compressed gas into an isentropic flow and causing the recooled compressed gas to expand isentropically. Although not illustrated, the isentropic nozzle (41) can be divided into a reducing portion, an expanding portion, and a throat portion. The reducing portion can be formed so that the flow cross-sectional area of ​​the recooled compressed gas can be gradually reduced, and the expanding portion can be formed so that the flow cross-sectional area of ​​the recooled compressed gas can be gradually increased. The reducing portion and the expanding portion can be connected by a throat portion, and the degree of isentropic expansion of the fluid can be controlled depending on the area ratio of the expanding portion and the throat portion.

[0065] Meanwhile, according to the law of conservation of energy in the flow of the isentropic nozzle (41), potential energy, heat loss, and work do not occur under adiabatic conditions, and the internal energy, that is, the sum of heat energy and kinetic energy, can always be constant. In an isolated system, internal energy and kinetic energy can be expressed as enthalpy, and the pressure and temperature can be extremely low through the isentropic nozzle (41) that can isentropically expand the fluid. Accordingly, the recooled compressed gas that has been isentropically expanded while passing through the isentropic nozzle (41) can exceed supersonic speeds, and the temperature can be lowered to -110 to -160 degrees, which is an amount that allows the gaseous carbon dioxide concentrated in the recooled compressed gas to undergo a phase change into a solid state. The carbon dioxide that has begun to solidify can undergo an exothermic reaction that releases heat to the surroundings, and releases heat within the system. On the other hand, gaseous nitrogen / oxygen, excluding carbon dioxide within the recooled compressed gas, do not undergo a phase change during the expansion process and their temperatures decrease, so that the exothermic reaction of the carbon dioxide and thermal equilibrium can be achieved.

[0066] The isentropic nozzle (41) receives the recooled compressed gas from the second cooling unit (30) and discharges it, but can induce the recooled compressed gas to be discharged at an increased speed by decreasing the pressure thereof compared to that of the recooled compressed gas. The recooled compressed gas expands inside the isentropic nozzle (41), and during the expansion process of the recooled compressed gas, the gaseous carbon dioxide contained in the recooled compressed gas may undergo a phase change into a solid state. In summary, during the process in which the recooled compressed gas passes through the isentropic nozzle (41), the carbon dioxide contained in the recooled compressed gas undergoes a phase change into a solid state, and other gases in the recooled compressed gas, for example, nitrogen / oxygen, expand into a gaseous state. When the recooled compressed gas expands in this way, the internal energy, that is, the thermal energy, is converted into kinetic energy, so that the expanded gas is cooled, and the gaseous carbon dioxide contained in the expanded gas may be frozen. Here, the expanded gas isentropically expanded in the isentropic nozzle (41) may be a mixture in which solid carbon dioxide and gaseous nitrogen / oxygen coexist. These gases can be supplied to a separation unit (50) and separated into solid carbon dioxide and the remaining gases.

[0067] The separation unit (50) can separate the isentropically expanded expanded gas from the phase change induction unit (40) into solid carbon dioxide and the remaining gas. To this end, the separation unit (50) can be connected to the isentropic nozzle (41) of the phase change induction unit (40) and can be provided as a solid-gas separator, for example.

[0068] The solid carbon dioxide separated in the separation unit (50) can be transferred to the tank (21) of the first cooling unit (20) and stored. The solid carbon dioxide transferred to the tank (21) and stored can be used as a cold source for pre-cooling the compressed gas compressed through the compression unit (10).

[0069] The remaining gas separated in the separation unit (50) corresponds to the gas in which solid carbon dioxide has been separated from the isentropically expanded expanded gas, and thus may be a gas in which the concentration of carbon dioxide is reduced compared to the isentropically expanded expanded gas. This remaining gas may be supplied to the expander (61) of the third cooling unit (60) described later and cooled.

[0070] The third cooling unit (60) can cool the remaining gas supplied from the separation unit (50) and supply it to the second cooling unit (30).

[0071] To this end, the third cooling unit (60) may include an expander (61) connected to the separation unit (50) to expand and cool the remaining gas separated by the separation unit (50).

[0072] The remaining gas (hereinafter referred to as the cooled remaining gas) expanded through the expander (61) and lowered in temperature can be supplied to the second cooling unit (30) and can be heat-exchanged with the compressed gas in the second cooling unit (30). In other words, since the cooled remaining gas corresponds to a cold heat source for cooling the compressed gas, the expander (61) can cool the remaining gas for heat exchange with the compressed gas in the second cooling unit (30).

[0073] The carbon dioxide separation and capture system (1) having the configuration described above can efficiently freeze carbon dioxide contained in the exhaust gas by isentropically expanding the compressed / cooled exhaust gas, and can minimize energy consumption and increase energy efficiency by reusing the cold heat of the frozen carbon dioxide in the carbon dioxide separation and capture process.

[0074] Meanwhile, in this embodiment, a case in which the pipe (22) includes a heat exchange part (222) arranged in the receiving space (2123) of the inner tank (212) has been described as an example, but this is merely an example and the spirit of the present invention is not limited thereby. Hereinafter, a modified example of the pipe (22') illustrated in FIG. 4 will be described.

[0075] As illustrated in FIG. 4, the pipe (22') may include an inlet part (221), a heat exchange part (222'), and a discharge part (223). The inlet part (221) and the discharge part (223) are substantially the same as the inlet part (221) and the discharge part (223) of the pipe (22) described with reference to FIGS. 1 to 3, so that redundant descriptions are omitted, and the heat exchange part (222') corresponding to the difference will be described below.

[0076] The heat exchange part (222') is arranged on the outer surface of the inner tank (212) and can connect the inlet part (221) and the discharge part (223). In other words, the compressed gas introduced into the inlet part (221) is pre-cooled while passing through the heat exchange part (222'), and the pre-cooled compressed gas can be discharged through the discharge part (223).

[0077] To this end, the heat exchange part (222') can connect the inlet part (221) and the discharge part (223) with multiple paths for heat exchange efficiency between the compressed gas and the solid carbon dioxide. In other words, multiple heat exchange parts (222') can be provided between the inlet part (221) and the discharge part (223). Accordingly, the compressed gas flowing inside the multiple heat exchange parts (222') exchanges heat with the cold heat of the solid carbon dioxide conducted to the inner tank (212) outside the multiple heat exchange parts (222'), so that the compressed gas and the solid carbon dioxide can exchange heat with each other without direct contact.

[0078] The pre-cooled compressed gas that has been cooled by receiving the cold heat of the solid carbon dioxide can be supplied to the second cooling unit (30), and the solid carbon dioxide that has transferred the cold heat to the compressed gas can be liquefied. The liquefied solid carbon dioxide (hereinafter referred to as “liquid carbon dioxide”) can be transported to and stored in a liquid carbon dioxide storage tank (25).

[0079] Hereinafter, a carbon dioxide separation and capture system according to another embodiment of the present invention will be described with reference to FIG. 5.

[0080] Referring to FIG. 5, a carbon dioxide separation and capture system (1a) according to another embodiment of the present invention may include a compression unit (10), a first cooling unit (20), a second cooling unit (30'), a phase change induction unit (40), a separation unit (50), and a third cooling unit (60). However, since the carbon dioxide separation and capture system (1a) illustrated in FIG. 5 is substantially the same as the carbon dioxide separation and capture system (1) described with reference to FIGS. 1 to 3 except for the second cooling unit (30'), the second cooling unit (30'), which is the difference, will be described below.

[0081] The second cooling unit (30') may include a pre-cooled compressed gas passage (31) that provides a flow path of the pre-cooled compressed gas pre-cooled in the first cooling unit (20), a cooled residual gas passage (32) that provides a flow path of the cooled residual gas expanded and cooled in the expander (61) of the third cooling unit (60), and a liquefied natural gas passage (33) that provides a flow path of the liquefied natural gas supplied from the liquefied natural gas supply source (3).

[0082] At this time, the liquefied natural gas flowing in the liquefied natural gas path (33) can be vaporized by receiving heat from the cooled residual gas flowing in the cooled residual gas path (32). The vaporized liquefied natural gas, for example, natural gas, can be supplied to the fuel supply device (4) and can be supplied to the exhaust gas supply source (2).

[0083] Hereinafter, a carbon dioxide separation and capture system according to another embodiment of the present invention will be described with reference to FIG. 6.

[0084] Referring to FIG. 6, a carbon dioxide separation and capture system (1b) according to another embodiment of the present invention may include a compression unit (10), a first cooling unit (20), a second cooling unit (30), a phase change induction unit (40), a separation unit (50), and a third cooling unit (60'). However, since the carbon dioxide separation and capture system (1a) illustrated in FIG. 6 is substantially the same as the carbon dioxide separation and capture system (1) described with reference to FIGS. 1 to 3 except for the third cooling unit (60'), the third cooling unit (60'), which is the difference, will be described below.

[0085] The third cooling unit (60') may include a compander expander (62) and a compander compressor (63).

[0086] The compander expander (62) is connected to the separator (50) to receive the remaining gas from the separator (50) and can expand and cool the remaining gas. The cooled remaining gas discharged from the compander expander (62) can be supplied to the cooled remaining gas path (32) of the second cooling unit (30) and can recool the precooled compressed gas flowing in the precooled compressed gas path (31).

[0087] The compander compressor (63) can be connected to the compander expander (62) by a shaft, and can compress the recooled compressed gas discharged from the second cooling unit (30) using the energy recovered from the compander expander (62). The recooled compressed gas compressed in the compander compressor (63) can be supplied to the phase change induction unit (40).

[0088] Meanwhile, when the re-cooled compressed gas is compressed through the compander compressor (63), compressed air with a higher pressure than before can be secured. Furthermore, the performance of the isentropic nozzle (41) of the phase change induction unit (40) can be maximized due to the compressed air with a higher pressure than before.

[0089] Hereinafter, a carbon dioxide separation and capture system according to another embodiment of the present invention will be described with reference to FIG. 7.

[0090] Referring to FIG. 7, a carbon dioxide separation and capture system (1c) according to another embodiment of the present invention may include a compression unit (10), a first cooling unit (20), a second cooling unit (30'), a phase change induction unit (40), a separation unit (50), and a third cooling unit (60'). However, since the carbon dioxide separation and capture system (1a) illustrated in FIG. 7 is substantially the same as the carbon dioxide separation and capture system (1a) described with reference to FIG. 5 except for the third cooling unit (60'), the third cooling unit (60'), which is the difference, will be described below.

[0091] The third cooling unit (60') may include a compander expander (62) and a compander compressor (63).

[0092] The compander expander (62) is connected to the separator (50) to receive the remaining gas from the separator (50) and expand the remaining gas to cool it.

[0093] At this time, the remaining cooled gas discharged from the compander expander (62) can be supplied to the remaining cooled gas path (32) of the second cooling unit (30), and the pre-cooled compressed gas flowing in the pre-cooled compressed gas path (31) can be re-cooled.

[0094] Meanwhile, the cooled residual gas supplied from the compander expander (62) to the cooled residual gas path (32) can vaporize the liquefied natural gas flowing in the liquefied natural gas path (33) of the second cooling unit (30). For example, the liquefied natural gas flowing in the liquefied natural gas path (33) can be vaporized by receiving heat from the cooled residual gas supplied from the compander expander (62) to the cooled residual gas path (32).

[0095] The compander compressor (63) can be connected to the compander expander (62) by a shaft, and can compress the re-cooled compressed gas discharged from the second cooling unit (30) using the energy recovered from the compander expander (62).

[0096] The compander compressor (63) can receive and compress the pre-cooled compressed gas discharged from the pre-cooled compressed gas path (31) of the second cooling unit (30). The re-cooled compressed gas compressed in the compander compressor (63) can be supplied to the phase change induction unit (40).

[0097] Hereinafter, a carbon dioxide separation and capture system according to another embodiment of the present invention will be described with reference to FIGS. 8 and 9.

[0098] Referring to FIGS. 8 and 9, a carbon dioxide separation and capture system (1d) according to another embodiment of the present invention may include a compression unit (10), a first cooling unit (20), a second cooling unit (30), a phase change induction unit (40), a separation unit (50), a third cooling unit (60), and a vaporization unit (70). However, since the carbon dioxide separation and capture system (1d) illustrated in FIGS. 8 and 9 is substantially the same as the carbon dioxide separation and capture system (1) described with reference to FIGS. 1 to 3 except for the vaporization unit (70), the vaporization unit (70) corresponding to the difference will be described below.

[0099] The vaporization unit (70) can receive the remaining gas discharged from the separation unit (50) and supply the heat of the remaining gas to the liquefied natural gas to induce vaporization of the liquefied natural gas. To this end, the vaporization unit (70) can be provided between the separation unit (50) and the third cooling unit (60).

[0100] At this time, the vaporization unit (70) may include a path through which the liquefied natural gas supplied from the liquefied natural gas supply source (3) flows and a path through which the remaining gas supplied from the separation unit (50) flows.

[0101] The liquefied natural gas supplied to the vaporization unit (70) and the remaining gas can exchange heat with each other. For example, the liquefied natural gas supplied to the vaporization unit (70) can be discharged from the vaporization unit (70) in a vaporized state as natural gas through heat exchange with the remaining gas. Accordingly, even without a separate vaporizer as in the past, the liquefied natural gas can be vaporized into natural gas, and this can be circulated to the fuel supply device (4) for use.

[0102] Meanwhile, the remaining gas that has exchanged heat with the liquefied natural gas is supplied to the expander (61) and expanded, so that it can be supplied to the cooled remaining gas path (32) of the second cooling unit (30) in a cooled state again.

[0103] Hereinafter, a carbon dioxide separation and capture system according to another embodiment of the present invention will be described with reference to FIG. 10.

[0104] Referring to FIG. 10, a carbon dioxide separation and capture system (1e) according to another embodiment of the present invention may include a compression unit (10), a first cooling unit (20), a second cooling unit (30), a phase change induction unit (40), a separation unit (50), a third cooling unit (60'), and a vaporization unit (70). However, the carbon dioxide separation and capture system (1e) illustrated in FIG. 10 is substantially the same as the carbon dioxide separation and capture system (1d) described with reference to FIGS. 8 and 9 except for the third cooling unit (60'), and therefore, the third cooling unit (60'), which is the difference, will be described below.

[0105] The third cooling unit (60') may include a compander expander (62) and a compander compressor (63).

[0106] The compander expander (62) can receive the remaining cooled gas discharged from the vaporizer (70) and expand it to cool it. Hereinafter, the gas discharged from the vaporizer (70) and introduced into the compander expander (62) is referred to as the first remaining cooled gas, and the gas discharged from the compander expander (62) is referred to as the second remaining cooled gas.

[0107] Meanwhile, the first cooled residual gas that has exchanged heat with the liquefied natural gas is supplied to the compander expander (62) and expanded, so that it can be supplied to the cooled residual gas path (32) of the second cooling unit (30) in a cooled state again. The cold heat of the second cooled residual gas supplied to the cooled residual gas path (32) in this way can be transferred to the pre-cooled compressed gas flowing in the pre-cooled compressed gas path (31), thereby re-cooling the compressed gas.

[0108] Hereinafter, a carbon dioxide separation and capture system according to another embodiment of the present invention will be described with reference to FIG. 11.

[0109] Referring to FIG. 11, a carbon dioxide separation and capture system (1f) according to another embodiment of the present invention may include a compression unit (10), a first cooling unit (20), a second cooling unit (30), a phase change induction unit (40), a separation unit (50), a third cooling unit (60), and a pre-cooled compressed gas compressor (80). However, since the carbon dioxide separation and capture system (1f) illustrated in FIG. 11 is substantially the same as the carbon dioxide separation and capture system (1) described with reference to FIG. 2 except for the pre-cooled compressed gas compressor (80), the pre-cooled compressed gas compressor (80), which corresponds to the difference, will be described below.

[0110] The pre-cooled compressed gas compressor (80) can compress the pre-cooled compressed gas by receiving power generated from the expander (61). To this end, the pre-cooled compressed gas compressor (80) can be provided between the first cooling unit (20) and the second cooling unit (30).

[0111] At this time, the expander (61) can receive and expand the remaining gas discharged from the separation unit (50), and the power generated in this process can be supplied to the pre-cooled compressed gas compressor (80). When the pre-cooled compressed gas compressor (80) is driven by this power, the pre-cooled compressed gas is compressed in the pre-cooled compressed gas compressor (80), and the pre-cooled compressed gas compressed in the pre-cooled compressed gas compressor (80) can be supplied to the pre-cooled compressed gas passage (31) of the second cooling unit (30).

[0112] Hereinafter, a carbon dioxide separation and capture system according to another embodiment of the present invention will be described with reference to FIG. 12.

[0113] Referring to FIG. 12, a carbon dioxide separation and capture system (1g) according to another embodiment of the present invention may include a compression unit (10), a first cooling unit (20), a second cooling unit (30), a phase change induction unit (40), a separation unit (50), a third cooling unit (60), a vaporization unit (70), and a pre-cooled compressed gas compressor (80). However, since the carbon dioxide separation and capture system (1g) illustrated in FIG. 12 is substantially the same as the carbon dioxide separation and capture system (1d) described with reference to FIG. 9 except for the pre-cooled compressed gas compressor (80), the pre-cooled compressed gas compressor (80), which corresponds to the difference, will be described below.

[0114] The pre-cooled compressed gas compressor (80) can compress the pre-cooled compressed gas by receiving power generated from the expander (61). To this end, the pre-cooled compressed gas compressor (80) can be provided between the first cooling unit (20) and the second cooling unit (30).

[0115] At this time, the expander (61) can receive and expand the remaining gas discharged from the vaporizer (70), for example, the remaining gas after transferring heat to the liquefied natural gas for vaporization of the liquefied natural gas, so that the remaining gas after cooling can be cooled again in the expander (61).

[0116] Meanwhile, the power generated in this process can be supplied to the pre-cooled compressed gas compressor (80). When the pre-cooled compressed gas compressor (80) is driven by the power generated in the expander (61), the pre-cooled compressed gas is compressed in the pre-cooled compressed gas compressor (80), and the pre-cooled compressed gas compressed in the pre-cooled compressed gas compressor (80) can be supplied to the pre-cooled compressed gas path (31) of the second cooling unit (30).

[0117] Hereinafter, a carbon dioxide separation and capture system according to another embodiment of the present invention will be described with reference to FIG. 13.

[0118] Referring to FIG. 13, a carbon dioxide separation and capture system (1h) according to another embodiment of the present invention may include a compression unit (10), a first cooling unit (20), a second cooling unit (30'), a phase change induction unit (40), a separation unit (50), a third cooling unit (60), and a pre-cooled compressed gas compressor (80). However, since the carbon dioxide separation and capture system (1h) illustrated in FIG. 13 is substantially the same as the carbon dioxide separation and capture system (1a) described with reference to FIG. 5 except for the pre-cooled compressed gas compressor (80), the pre-cooled compressed gas compressor (80) corresponding to the difference will be described below.

[0119] The pre-cooled compressed gas compressor (80) can compress the pre-cooled compressed gas by receiving power generated from the expander (61). To this end, the pre-cooled compressed gas compressor (80) can be provided between the first cooling unit (20) and the second cooling unit (30').

[0120] At this time, the expander (61) can receive and expand the remaining gas discharged from the separation unit (50), and the power generated in this process can be supplied to the pre-cooled compressed gas compressor (80).

[0121] Meanwhile, when the pre-cooled compressed gas compressor (80) is driven by this power, the pre-cooled compressed gas is compressed in the pre-cooled compressed gas compressor (80), and the pre-cooled compressed gas compressed in the pre-cooled compressed gas compressor (80) can be supplied to the pre-cooled compressed gas path (31) of the second cooling unit (30'). Although the embodiments of the present invention have been described above as specific embodiments, these are merely examples, and the present invention is not limited thereto, but should be construed as having the broadest scope according to the basic idea disclosed in the present specification. Those skilled in the art can implement a pattern of a shape not specified by combining / substituting the disclosed embodiments, but this also does not depart from the scope of the present invention. In addition, those skilled in the art can easily change or modify the disclosed embodiments based on the present specification, and it is obvious that such changes or modifications also fall within the scope of the present invention.

Claims

1. A compression unit that receives exhaust gas and compresses it; A first cooling unit connected to the compression unit and precooling compressed gas compressed in the compression unit; A second cooling unit connected to the first cooling unit and re-cooling the pre-cooled compressed gas pre-cooled in the first cooling unit; A phase change inducing unit connected to the second cooling unit and causing the re-cooled compressed gas re-cooled in the second cooling unit to expand isentropically to induce a phase change of gaseous carbon dioxide contained in the re-cooled compressed gas into a solid state; A separation unit connected to the phase change induction unit and separating the isentropically expanded expanded gas in the phase change induction unit into solid carbon dioxide and the remaining gas; and A third cooling unit connected to the separation unit, receiving the remaining gas from the separation unit, and cooling the remaining gas to supply it to the second cooling unit. Carbon dioxide separation and capture system.

2. In paragraph 1, The above first cooling unit, A tank connected to the above separation unit and containing the solid carbon dioxide supplied from the above separation unit; and A pipe connecting the compression unit and the second cooling unit, wherein at least a portion of the pipe is disposed either inside or outside the tank, The compressed gas flowing through the pipe arranged either inside or outside the tank receives the cold heat of the solid carbon dioxide contained in the tank. Carbon dioxide separation and capture system.

3. In paragraph 2, The above pipe is, An inlet part connected to the compression unit and into which the compressed gas flows; A discharge part connected to the second cooling unit and through which the pre-cooled compressed gas is discharged; and A heat exchange part connecting the inlet part and the outlet part and disposed either inside or outside the tank, Carbon dioxide separation and capture system.

4. In paragraph 1, The third cooling unit is, An expander connected to the separating unit and configured to expand and cool the remaining gas separated by the separating unit, Carbon dioxide separation and capture system.

5. In paragraph 4, The above second cooling unit, A pre-cooled compressed gas path that provides a flow path of the pre-cooled compressed gas pre-cooled in the first cooling unit; and Includes a cooled residual gas path that provides a flow path for cooled residual gas expanded and cooled in the above expander, The pre-cooled compressed gas flowing in the pre-cooled compressed gas path is cooled by receiving the cooling heat of the cooled remaining gas flowing in the cooled remaining gas path and then supplied to the phase change induction unit. Carbon dioxide separation and capture system.

6. In paragraph 5, The above second cooling unit, Further comprising a liquefied natural gas flow path that provides a flow path for liquefied natural gas supplied from a liquefied natural gas supply source, The liquefied natural gas flowing in the above liquefied natural gas path is vaporized by receiving heat from the remaining cooled gas flowing in the remaining cooled gas path. Carbon dioxide separation and capture system.

7. In paragraph 1, The third cooling unit is, A compander expander connected to the separating unit, receiving the remaining gas from the separating unit, and expanding and cooling the remaining gas; and It includes a compander compressor connected to the above compander expander by a shaft, The above compander compressor, Compressing the re-cooled compressed gas discharged from the second cooling unit using the energy recovered from the compander expander, and supplying the compressed re-cooled compressed gas to the phase change induction unit. Carbon dioxide separation and capture system.

8. In paragraph 4 or paragraph 7, Further comprising a vaporization unit provided between the above separation unit and the third cooling unit, The above vaporizer, The remaining gas discharged from the above separation unit is supplied, and the heat of the remaining gas is supplied to the liquefied natural gas to induce vaporization of the liquefied natural gas. Carbon dioxide separation and capture system.

9. In paragraph 8, The first cooling remaining gas cooled by transferring heat to the liquefied natural gas through the above vaporization unit is supplied to the third cooling unit and cooled, The second cooling remaining gas cooled in the third cooling unit is supplied to the second cooling unit. Carbon dioxide separation and capture system.

10. In paragraph 4, Further comprising a pre-cooling compressed gas compressor provided between the first cooling unit and the second cooling unit, The above pre-cooled compressed gas compressor, Compressing the pre-cooled compressed gas by receiving power generated from the above expander, Carbon dioxide separation and capture system.

11. In paragraph 10, It further includes a vaporization unit provided between the separator and the expander, and inducing vaporization of the liquefied natural gas by using the heat of the remaining gas discharged from the separator. The remaining cooled gas is cooled by transferring heat to the liquefied natural gas through the vaporizer and is supplied to the expander to be expanded and cooled again. Carbon dioxide separation and capture system.

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