KR102740614B1 - Equipment for wet type carbon dioxide capturing with absorbant recirculation - Google Patents

Abstract

The present invention relates to a wet carbon dioxide capture facility with recirculating absorbent, comprising: a pretreatment facility for removing sulfur compounds contained in the exhaust gas; an inlet pipe through which the exhaust gas from which sulfur compounds have been removed in the pretreatment facility moves; an absorption tower through which the exhaust gas is introduced through the inlet pipe and through which the carbon dioxide contained in the exhaust gas reacts with an absorbent; a first pipe through which a carbon dioxide-rich absorbent, which has reacted the carbon dioxide with the absorbent, moves; a heat exchanger provided in the first pipe and through which heat exchange with the carbon dioxide-rich absorbent is performed; a stripping tower through which the carbon dioxide-rich absorbent is introduced and through which carbon dioxide is separated from the carbon dioxide-rich absorbent; a second pipe connecting the stripping tower and the absorption tower and through which a carbon dioxide-lean absorbent from which the carbon dioxide has been separated moves; a recirculation pipe branching from the first pipe and connected to the absorption tower; and characterized in that the carbon dioxide-rich absorbent moving into the first pipe through the recirculation pipe is re-introduced into the absorption tower.

Description

{Equipment for wet type carbon dioxide capturing with absorbant recirculation}

The present invention relates to a wet carbon dioxide capture facility with recirculating absorbent, and more specifically, to a wet carbon dioxide capture facility with recirculating absorbent, which can re-inject a portion of the circulated absorbent into an absorption tower to increase the amount of carbon dioxide absorbed in the absorption tower.

Recently, as the seriousness of the global warming phenomenon has begun to be recognized, countries around the world are struggling to come up with countermeasures for greenhouse gases, and one of the biggest factors in this global warming is carbon dioxide. Therefore, research is actively being conducted on technologies that efficiently capture carbon dioxide, the most important greenhouse gas, and reduce carbon dioxide in exhaust gas.

CCS (Carbon Capture & Storage) is a general term for technologies related to capturing, compressing, transporting, and storing carbon dioxide. Among these, the wet amine process is being evaluated as a feasible commercialization technology as a technology that separates carbon dioxide from exhaust gas emitted from thermal power plants through a chemical absorption process.

In general, liquid amine compounds or liquid ammonia have the property of absorbing carbon dioxide, so they can be used in processes for removing sulfur components in petroleum refining processes or for separating carbon dioxide from exhaust gas emitted from thermal power plants.

Figure 1 illustrates a carbon dioxide capture facility using a conventional wet amine process. Referring to Figure 1, a wet carbon dioxide capture facility using amine includes an absorption tower (20) for contacting an amine-based absorbent with exhaust gas, a stripping tower (50) for stripping the absorbed carbon dioxide, and a pretreatment facility for exhaust gas (10).

A representative absorbent for wet carbon dioxide capture facilities using amines is MEA (Monoethanol Amine), and improved absorbents for wet carbon dioxide capture facilities can be used to save renewable energy and prevent deterioration.

When a wet carbon dioxide capture facility is applied to a coal-fired power plant, the exhaust gas flowing into the carbon dioxide capture facility passes through a pretreatment facility (10) equipped with a desulfurization (FGD: Flue Gas Desulfurization) facility, a denitrification (SCR: Selective Catalytic Reduction) facility, and a dust collection facility, and then flows into an absorption tower (20) through an inlet pipe (12).

The carbon dioxide content in the exhaust gas varies depending on the fuel being burned and the operating conditions, but the carbon dioxide content in the exhaust gas of a coal-fired power plant is typically around 15 vol.%, and in a combined cycle power plant, the concentration of carbon dioxide in the exhaust gas can be around 3 to 4 vol.%. A portion of the exhaust gas is transported to a carbon dioxide capture facility by a supply fan (11). The introduced exhaust gas is introduced into a separate quenching tower (16). When the exhaust gas of a coal-fired power plant is introduced, the sulfur oxides remaining in the exhaust gas are further removed, and the exhaust gas temperature is lowered to around 40°C.

When the exhaust gas of a combined cycle power plant is introduced, the purpose is to lower the temperature of the exhaust gas to approximately 40℃ rather than to further remove the remaining sulfur oxides since there is almost no sulfur oxide in the exhaust gas. In both coal-fired power plants and combined cycle power plants, moisture in the exhaust gas is removed as condensate in the quenching tower, and after the quenching tower, it flows into the absorption tower at the saturated vapor pressure of the corresponding temperature (approximately 40℃).

In this way, the exhaust gas that has passed through the exhaust gas pretreatment facility (10) flows into the lower part of the absorption tower (20), and when a liquid absorbent is injected from the upper part of the absorption tower (20), gas-liquid contact occurs while they flow countercurrently within the absorption tower (20), and carbon dioxide is absorbed by the liquid absorbent.

The exhaust gas from which carbon dioxide has been removed is discharged from the upper part of the absorption tower (20), and the carbon dioxide rich absorbent (rich solution) that has absorbed carbon dioxide is discharged from the lower part of the absorption tower (20). The carbon dioxide rich absorbent that has absorbed carbon dioxide contains carbon dioxide and has a temperature of about 40 to 50°C. The temperature of the exhaust gas from which carbon dioxide has been removed is lowered to about 40°C due to the water spray at the upper part of the absorption tower (20), and the exhaust gas is discharged again through the main chimney or a separate chimney.

The carbon dioxide rich absorbent is moved through the first pipe (30) and can be introduced into the heat exchanger (40) through the rich solution pump (31) provided in the first pipe (30). The carbon dioxide rich absorbent that has passed through the heat exchanger (40) is introduced into the upper part of the stripping tower (50) while recovering sensible heat and being heated to a temperature of 90 to 100°C.

The carbon dioxide rich absorbent flows from the top to the bottom of the stripping tower (50) and is heated by heat energy, so that the absorbent and carbon dioxide are separated, and the separated carbon dioxide is discharged from the top of the stripping tower (50). The temperature of the high-concentration carbon dioxide discharged from the top of the stripping tower (50) is approximately 80 to 90°C, which is almost the same as the temperature at the top of the stripping tower (50), and since it contains moisture corresponding to the saturated vapor pressure, the moisture can be removed through the condenser (70) and the reflux drum (71).

The moisture removed from the condenser (70) and the reflux drum (71) is returned to the stripping tower (50) as condensate. The carbon dioxide from which moisture has been removed is supplied to a compression facility for transport, storage, or reuse.

A carbon dioxide lean absorbent (lean solution) is discharged from the bottom of the stripping tower (50). The temperature of the carbon dioxide lean absorbent is approximately 105 to 120°C, and it is introduced into the heat exchanger (40) through the second pipe (60) to transfer sensible heat to the carbon dioxide rich absorbent. The carbon dioxide lean absorbent that has lost sensible heat is introduced into the upper part of the absorption tower (20) through the lean solution pump (61) provided in the second pipe (60), and comes into contact with the exhaust gas pretreated in the quenching tower (16).

In this way, the carbon dioxide lean absorbent from which carbon dioxide has been separated is discharged from the bottom of the stripping tower (50), and some of the absorbent in the stripping tower (50) in which carbon dioxide is being separated may be introduced into the reheater (80).

Steam of about 2 bar.g or more is introduced into the reheater (80), and the absorbent introduced into the reheater (80) is heated by the steam. Carbon dioxide and steam are generated from the absorbent inside the reheater (80), and this mixed gas is introduced into the stripping tower (50) to provide heat energy for separating carbon dioxide from the carbon dioxide-rich absorbent.

Carbon dioxide rich absorbents are diverse, but most of them have a boiling point higher than that of water, and the degassing temperature of carbon dioxide in the carbon dioxide rich absorbent is also higher than that of water. Therefore, the substance that boils and vaporizes first in the reheater (80) may be water. Most of the substance heated in the reheater (80) is water, and the water is heated and converted into vapor and then flows into the stripping tower (50). Accordingly, the substance that heats the carbon dioxide rich absorbent that flows into the upper portion of the stripping tower (50) may be vapor from evaporated water.

The absorbent from which carbon dioxide has been separated in the reheater (80) is fed back into the stripping tower (50). The steam fed into the reheater (80) transfers latent heat and is fed into and collected in the form of condensate in the condensate tank (81) and then returned to the steam production process.

The amount of steam flowing into the reheater (80) varies depending on the circulation speed of the absorbent by the rich solution pump (31) and the lean solution pump (61). When the flow rate of the two pumps is increased, the circulation amount of the absorbent increases. When the circulation amount of the absorbent increases, the liquid-gas ratio (L/G) in the absorption tower (20) increases, and the absorption amount of carbon dioxide in the absorption tower (20) increases.

Of course, even if the gas-liquid ratio increases, the carbon dioxide absorption rate (the ratio of the weight of carbon dioxide absorbed per unit weight of absorbent) does not increase. Rather, if the gas-liquid ratio increases, there may be absorbents that cannot absorb carbon dioxide in the absorption tower, so the carbon dioxide absorption rate of the absorbent may decrease.

Conversely, if the circulation amount of the absorbent decreases, the gas-liquid ratio decreases, so that the absorption tower (20) may not sufficiently absorb carbon dioxide, and thus the desired carbon dioxide removal rate may not be achieved. The optimal gas-liquid ratio in the absorption tower (20) varies depending on the absorbent, and is derived experimentally. In theory, it is desirable for the carbon dioxide-rich absorbent at the bottom of the absorption tower (20) to capture all carbon dioxide.

In order to sufficiently strip the carbon dioxide-rich absorbent that has absorbed carbon dioxide in the stripping tower (50), sufficient residence time and sufficient steam must be supplied in the stripping tower (50). Otherwise, the absorbent liquid in the stripping tower (50) is not sufficiently regenerated, so that the carbon dioxide that has not been degassed is contained in the carbon dioxide-lean absorbent, and thus carbon dioxide may not be sufficiently absorbed in the absorption tower (20). In other words, the absorbent liquid that has absorbed carbon dioxide continues to circulate in a certain amount within the carbon dioxide capture facility, making the system inefficient.

The carbon dioxide rich absorbent is fed into the stripping tower (50), but regardless of the amount of carbon dioxide absorbed by the absorbent, the water component of the absorbent must be vaporized in the stripping tower, so the amount of carbon dioxide stripped must be less than the amount of steam being injected. Therefore, the circulation amount of the absorbent must be experimentally optimized for operation.

Combined cycle power plants have a large load fluctuation of gas turbines. Depending on the power supply command, DSS (Daily Start and Stop) operation is performed, and even during one-day operation, the maximum load and partial load operation may change frequently. The flow rate and composition of the exhaust gas generated vary depending on the operating load of the gas turbine. In particular, the CO2 concentration is about 3.5 vol.% at 35% partial load, but increases to about 4.8 vol.% at rated load.

A portion of the exhaust gas generated from a power plant is extracted and fed into a wet carbon dioxide capture facility, and the exhaust gas flow rate is maintained constant. While the exhaust gas flow rate fed into the wet carbon dioxide capture facility is constant, if the concentration of carbon dioxide changes depending on the load of the gas turbine, not only does the carbon dioxide absorption rate in the absorption tower (20) change, but the carbon dioxide flow rate produced in the stripping tower (50) also changes.

After the desorption tower (50), a compression facility is installed to utilize or store carbon dioxide. However, if there is a change in the flow rate flowing into the compression facility, stable operation is difficult. Therefore, in order to operate the compression facility stably, it is desirable to keep the flow rate of carbon dioxide produced in the desorption tower (50) as constant as possible.

Therefore, wet carbon dioxide capture facilities for capturing carbon dioxide from exhaust gas generated from combined cycle power plant gas turbines must be able to actively respond to load fluctuations in the gas turbine. However, conventional wet carbon dioxide capture facilities are generally operated under conditions where a constant flow rate and constant carbon dioxide concentration are introduced, so there is a problem in that there is no countermeasure for conditions where the inflow conditions change.

The present invention is intended to solve the above-described problems, and more specifically, relates to a wet carbon dioxide capture facility in which an absorbent is recycled, in which a portion of the circulated absorbent can be reintroduced into the absorption tower to increase the amount of carbon dioxide absorbed in the absorption tower for absorbing carbon dioxide.

In order to solve the above-described problems, the wet carbon dioxide capture facility with recirculating absorbent of the present invention is a carbon dioxide capture facility for capturing carbon dioxide contained in exhaust gas, comprising: a pretreatment facility for removing sulfur compounds contained in the exhaust gas or lowering the temperature of the exhaust gas; an inlet pipe through which the exhaust gas treated in the pretreatment facility moves; an absorption tower through which the exhaust gas flows in through the inlet pipe and which reacts the carbon dioxide contained in the exhaust gas with an absorbent; a first pipe through which a carbon dioxide-rich absorbent, which has reacted the carbon dioxide and the absorbent, flows; a heat exchanger provided in the first pipe and through which heat exchange with the carbon dioxide-rich absorbent is performed; a stripping tower through which the carbon dioxide-rich absorbent flows in and which separates carbon dioxide from the carbon dioxide-rich absorbent; a second pipe connecting the stripping tower and the absorption tower and through which a carbon dioxide-lean absorbent from which the carbon dioxide is separated flows; It includes a recirculation pipe branched from the first pipe and connected to the absorption tower; and is characterized in that the carbon dioxide rich absorbent moving to the first pipe through the recirculation pipe is re-introduced into the absorption tower.

In order to solve the above-described problem, the pretreatment facility of the wet carbon dioxide capture facility with recirculating absorbent of the present invention may include a flow rate control valve for controlling the flow rate of the exhaust gas flowing into the absorption tower.

In order to solve the above-described problem, the pretreatment facility of the wet carbon dioxide capture facility with recirculating absorbent of the present invention includes a flow meter capable of measuring the flow rate of the exhaust gas, and the flow rate control valve can be opened and closed according to the flow rate measured by the flow meter.

In order to solve the above-described problem, the pretreatment facility of the wet carbon dioxide capture facility with recirculating absorbent of the present invention includes a supply fan for moving exhaust gas, and the flow rate control valve can be installed in a return pipe connecting the front and rear ends of the supply fan.

In order to solve the above-described problem, the pretreatment facility of the wet carbon dioxide capture facility with recirculating absorbent of the present invention may include a carbon dioxide analyzer that measures the concentration of carbon dioxide contained in the exhaust gas.

In order to solve the above-described problem, the first pipe of the wet carbon dioxide capture facility with recirculating absorbent of the present invention is provided with a first rich solution pump that provides power to move the carbon dioxide rich absorbent, and the recirculation pipe can be connected to the absorption tower while branching from the first pipe connecting between the absorption tower and the first rich solution pump.

In order to solve the above-described problem, the recirculation pipe of the wet carbon dioxide capture facility in which the absorbent of the present invention recirculates may be equipped with a second rich solution pump that provides power to move the carbon dioxide rich absorbent to the absorption tower.

In order to solve the above-described problems, the wet carbon dioxide capture facility with recirculating absorbent of the present invention further includes a rich analyzer capable of measuring at least one of pH, viscosity, and specific gravity of the carbon dioxide rich absorbent collected at the bottom of the absorption tower, and a control unit that controls the operation of the first rich solution pump and the second rich solution pump, wherein the control unit can control the operation of the first rich solution pump and the second rich solution pump according to the measured value of the rich analyzer.

In order to solve the above-described problem, the first pipe of the wet carbon dioxide capture facility with recirculating absorbent of the present invention is provided with a first rich solution pump that provides power to move the carbon dioxide rich absorbent, and the recirculation pipe can be connected to the absorption tower while branching from the first pipe connecting the first rich solution pump and the heat exchanger.

In order to solve the above-described problem, the recirculation pipe of the wet carbon dioxide capture facility in which the absorbent of the present invention recirculates may be provided with a first control valve for opening and closing the recirculation pipe.

In order to solve the above-described problem, the first pipe connecting the first rich solution pump and the heat exchanger of the wet carbon dioxide capture facility with recirculating absorbent of the present invention may be provided with a second control valve for opening and closing the first pipe.

In order to solve the above-described problem, the wet carbon dioxide capture facility with recirculating absorbent of the present invention further includes a rich analyzer capable of measuring at least one of pH, viscosity, and specific gravity of the carbon dioxide rich absorbent collected at the bottom of the absorption tower, and a control unit that controls the operation of the first control valve and the second control valve, wherein the control unit can control the operation of the first control valve and the second control valve according to the measured value of the rich analyzer.

In order to solve the above-described problem, the point at which the recirculation pipe is connected in the absorption tower of the wet carbon dioxide capture facility with recirculating absorbent of the present invention may be a point lower than the point at which the second pipe is connected to the absorption tower.

The present invention relates to a wet carbon dioxide capture facility in which an absorbent is recycled. The facility has an advantage in that the flow rate of carbon dioxide produced in a stripping tower can be maintained constant even if the concentration and flow rate of carbon dioxide flowing into the wet carbon dioxide capture facility change by reintroducing a portion of the circulated absorbent into the absorption tower to increase the amount of carbon dioxide absorbed in the absorption tower.

The present invention has an advantage in that it can stably operate a compression facility system operated with carbon dioxide discharged from a stripping tower by maintaining the flow rate of carbon dioxide produced from a stripping tower constant even when the concentration and flow rate of carbon dioxide flowing into a wet carbon dioxide capture facility change.

In addition, the present invention has an advantage in that it can maximize the carbon dioxide absorption rate of the carbon dioxide-rich absorbent by recycling a portion of the carbon dioxide-rich absorbent that has absorbed carbon dioxide in the absorption tower to increase the liquid-gas ratio (L/G) in the absorption tower, thereby reducing the amount of heat energy or steam required for carbon dioxide separation in the stripping tower.

In addition, the present invention has an advantage in that the flow rate of exhaust gas flowing into a carbon dioxide capture facility can be controlled according to the concentration of carbon dioxide through a carbon dioxide analyzer capable of measuring the carbon dioxide concentration of exhaust gas in real time and a flow rate control valve capable of controlling the flow rate of exhaust gas.

Figure 1 is a drawing showing a conventional wet carbon dioxide capture facility.
FIG. 2 is a drawing showing a wet carbon dioxide capture facility according to an embodiment of the present invention.
FIG. 3 is a drawing showing a wet carbon dioxide capture facility according to another embodiment of the present invention.
FIG. 4 is a drawing showing the control of the operation of the first rich solution pump and the second rich solution pump and the first regulating valve and the second regulating valve through a rich analyzer and a control unit according to an embodiment of the present invention.

This specification clarifies the scope of the present invention and explains the principles of the present invention and discloses embodiments so that a person having ordinary skill in the art to which the present invention pertains can practice the present invention. The disclosed embodiments can be implemented in various forms.

Expressions such as "includes" or "may include", which may be used in various embodiments of the present invention, indicate the presence of the disclosed corresponding function, operation or component, etc., and do not limit one or more additional functions, operations or components, etc. In addition, it should be understood that in various embodiments of the present invention, terms such as "includes" or "has" are intended to specify the presence of a feature, number, step, operation, component, part or a combination thereof described in the specification, but do not exclude in advance the possibility of the presence or addition of one or more other features, numbers, steps, operations, components, parts or combinations thereof.

When it is said that a component is "connected, coupled" to another component, it should be understood that said component may be directly connected or coupled to said other component, but that there may also be other new components between said component and said other component. On the other hand, when it is said that a component is "directly connected" or "directly coupled" to another component, it should be understood that no other new components exist between said component and said other component.

The terms first, second, etc. used in this specification may be used to describe various components, but the components should not be limited by the terms. The terms are used only for the purpose of distinguishing one component from another.

The present invention relates to a wet carbon dioxide capture facility with recirculating absorbent, and more particularly, to a wet carbon dioxide capture facility with recirculating absorbent, in which a portion of the circulated absorbent can be reintroduced into the absorption tower to increase the amount of carbon dioxide absorbed in the absorption tower for absorbing carbon dioxide.

A wet carbon dioxide capture facility with recirculating absorbent according to an embodiment of the present invention increases the amount of carbon dioxide absorbed by recycling the carbon dioxide-rich absorbent that has absorbed carbon dioxide in the absorption tower to the absorption tower in order to keep the flow rate of carbon dioxide produced in the stripping tower constant even when the concentration and flow rate of carbon dioxide flowing into the wet carbon dioxide capture facility vary. Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the attached drawings.

Referring to FIG. 2, a wet carbon dioxide capture facility with recirculating absorbent according to an embodiment of the present invention includes a pretreatment facility (110), an inlet pipe (112), an absorption tower (120), a first pipe (130), a heat exchanger (140), a stripping tower (150), a second pipe (160), and a recirculation pipe (210).

The above pretreatment facility (110) may further remove sulfur compounds contained in the exhaust gas or lower the temperature of the exhaust gas, and the inlet pipe (112) may be a pipe through which the exhaust gas treated in the pretreatment facility (110) moves. The inlet pipe (112) may be a pipe connecting the pretreatment facility (110) and the absorption tower (120).

The above pretreatment facility (110) is equipped with a desulfurization (FGD: Flue Gas Desulfurization) facility, a denitrification (SCR: Selective Catalytic Reduction) facility, and a dust collection facility, and the exhaust gas passing through the above pretreatment facility (10) can be introduced into the absorption tower (120) through the inlet pipe (112).

The above pretreatment facility (110) includes a supply fan (111) for moving exhaust gas and a quenching tower (116), and the exhaust gas can be moved through the supply fan (111). The quenching tower (116) can additionally remove sulfur oxides remaining in the exhaust gas, and as the exhaust gas passes through the quenching tower (116), the remaining sulfur oxides are further removed, and after the temperature is lowered to about 40° C., it can be moved to the absorption tower (120).

The above absorption tower (120) receives the exhaust gas of the pretreatment facility (110) through the inflow pipe (112), and the carbon dioxide contained in the exhaust gas can react with the absorbent in the absorption tower (120). The above absorption tower (110) can adopt the configuration of a conventional absorption tower as it is.

According to an embodiment of the present invention, exhaust gas containing carbon dioxide is introduced into the lower part of the absorption tower (120) through the inlet pipe (112). When a liquid absorbent is introduced into the upper part of the absorption tower (120), the exhaust gas and the liquid absorbent flow countercurrently with each other inside the absorption tower (120) and come into gas-liquid contact, so that carbon dioxide is absorbed into the liquid absorbent, thereby forming a carbon dioxide-rich absorbent (CO2-rich absorbent, rich solution).

The first pipe (130) is a pipe through which the carbon dioxide rich absorbent, which has reacted with the carbon dioxide and the absorbent, moves, and extends from the lower part of the absorption tower (120). The temperature of the carbon dioxide rich absorbent can be maintained at approximately 40° C. to 50° C.

The above heat exchanger (140) is provided on the first pipe (130) and is where heat exchange of the carbon dioxide rich absorbent is performed. Specifically, the carbon dioxide rich absorbent exchanges heat with the carbon dioxide lean absorbent (CO2-Lean Solution; Lean Solution) derived from the stripping tower (150) described below, and the heat exchanger (140) is where the carbon dioxide rich absorbent and the carbon dioxide lean absorbent exchange heat while crossing each other.

The above-mentioned stripping tower (150) is a place where the carbon dioxide rich absorbent is introduced and carbon dioxide can be separated from the carbon dioxide rich absorbent. The carbon dioxide rich absorbent discharged from the absorption tower (120) can be moved to the upper part of the stripping tower (150) through the first pipe (130). The stripping tower (150), like the absorption tower (120), can adopt the configuration of a conventional stripping tower as it is.

Specifically, in the stripping tower (150), the carbon dioxide-rich absorbent is heated by heat energy to separate carbon dioxide from the amine absorbent, and the separated carbon dioxide is discharged to the upper part of the stripping tower (150). The carbon dioxide-lean absorbent (CO2-Lean Solution, Lean Solution) from which carbon dioxide is separated is discharged to the lower part of the stripping tower (150) and flows to the heat exchanger (140).

The second pipe (160) above is a pipe connecting the stripping tower (150) and the absorption tower (120), and may be a pipe through which the carbon dioxide lean absorbent, in which carbon dioxide is separated from the carbon dioxide rich absorbent, moves. The second pipe (160) may connect the stripping tower (150) and the absorption tower (120), and the heat exchanger (140) may be provided on the second pipe (160).

The second pipe (160) extends from the lower part of the stripping tower (150). The carbon dioxide lean absorbent discharged from the lower part of the stripping tower (150) has a temperature of approximately 105° C. to 115° C., flows to the heat exchanger (140), exchanges heat with the carbon dioxide rich absorbent within the heat exchanger (140), and then flows into the upper part of the absorption tower (120).

According to an embodiment of the present invention, the first pipe (130) may be equipped with a first rich solution pump (131) that provides power to move a carbon dioxide rich absorbent, and the second pipe (160) may be equipped with a lean solution pump (161) that provides power to move a carbon dioxide lean absorbent.

The first rich solution pump (131) may be provided between the absorption tower (120) and the heat exchanger (140), and the carbon dioxide rich absorbent may be moved to the heat exchanger (140) through the first rich solution pump (131).

The above lean solution pump (161) may be provided between the heat exchanger (140) and the absorption tower (120), and the carbon dioxide lean absorbent may be moved from the heat exchanger (140) to the absorption tower (120) through the lean solution pump (161).

A wet carbon dioxide capture facility with recirculating absorbent according to an embodiment of the present invention may further include a condenser (170), a reflux drum (171), a reheater (180), and a condensate tank (181).

The above condenser (170), the reflux drum (171), the reheater (180), and the condensate tank (181) may be the same as the conventional condenser (70), reflux drum (71), reheater (80), and condensate tank (81) described above in the background art, and therefore, a detailed description thereof will be omitted.

According to an embodiment of the present invention, when the load of a gas turbine in a power plant generating exhaust gas changes, the concentration of carbon dioxide in the exhaust gas may change. The wet carbon dioxide capture facility with recirculating absorbent according to an embodiment of the present invention can maintain the production amount of carbon dioxide produced in the stripping tower (120) constant, so that even if the concentration of carbon dioxide in the exhaust gas changes, the production amount of carbon dioxide produced in the stripping tower (120) can be maintained constant if the total amount of carbon dioxide flowing into the absorption tower (120) is maintained.

To this end, the pretreatment facility (110) according to an embodiment of the present invention may include a flow control valve (113), a flow meter (114), and a carbon dioxide analyzer (115).

The above flow control valve (113) can control the flow rate of exhaust gas flowing into the absorption tower (120). The flow meter (114) can measure the flow rate of the exhaust gas, and the carbon dioxide analyzer (115) can measure the concentration of carbon dioxide contained in the exhaust gas.

The above flow control valve (113) can be opened and closed according to the flow rate measured by the flow meter (114), thereby controlling the flow rate of exhaust gas flowing into the absorption tower (120).

According to an embodiment of the present invention, the flow rate control valve (113) can control the flow rate of exhaust gas flowing into the absorption tower (120) according to the concentration of carbon dioxide contained in the exhaust gas measured by the carbon dioxide analyzer (115).

Specifically, when the load of the gas turbine of the power plant increases and the concentration of carbon dioxide contained in the exhaust gas increases, the flow rate of the exhaust gas flowing into the absorption tower (120) can be reduced through the flow rate control valve (113). In addition, when the load of the gas turbine of the power plant decreases and the concentration of carbon dioxide contained in the exhaust gas decreases, the flow rate of the exhaust gas flowing into the absorption tower (120) can be increased through the flow rate control valve (113).

The pretreatment facility (110) according to an embodiment of the present invention includes a supply fan (111) that moves exhaust gas, and the flow rate control valve (113) can be installed in a return pipe (117) connecting the front and rear ends of the supply fan (111).

The above return pipe (117) branches off from the rear end of the supply fan (111) and is connected to the front end of the supply fan (111). The exhaust gas that has passed through the supply fan (111) through the return pipe (117) can move back to the front end of the supply fan (111). Here, the rear end of the supply fan (111) may be in the direction toward the absorption tower (120), and the front end of the supply fan (111) may be in the direction toward the power plant.

The above flow rate control valve (113) may be installed at the rear end of the supply fan (110) to control the flow rate of the exhaust gas. However, if the flow rate of the exhaust gas flowing into the absorption tower (120) is large, it may be difficult to install the flow rate control valve (113) because the pipe diameter is large.

Therefore, the flow rate control valve (113) according to the embodiment of the present invention can be installed in the return pipe (117) connecting the front and rear ends of the supply fan (111). By installing the flow rate control valve (113) in the return pipe (117), the supply fan (111) can be operated at a constant flow rate and constant discharge pressure, thereby enabling stable operation of the equipment.

Specifically, the exhaust gas moved to the rear end of the supply fan (111) through the flow control valve (113) and the return pipe (117) can be returned to the front end of the supply fan (111), thereby controlling the flow rate of the exhaust gas flowing into the absorption tower (120).

If the opening rate of the above flow control valve (113) is increased, the flow rate of the return pipe (117) increases, and the flow rate of the exhaust gas flowing into the absorption tower (120) may decrease. Conversely, if the opening rate of the above flow control valve (113) is decreased, the flow rate of the return pipe (117) decreases, and the flow rate of the exhaust gas flowing into the absorption tower (120) may increase.

Here, the opening rate of the flow control valve (113) can be adjusted so that the total amount of carbon dioxide calculated from the concentration of carbon dioxide contained in the exhaust gas measured by the carbon dioxide analyzer (115) and the flow rate of the exhaust gas measured by the flow meter (114) is kept constant.

According to an embodiment of the present invention, in order to maintain the production amount of carbon dioxide produced in the stripping tower (120) constant, the liquid-gas ratio (L/G) of the absorption tower (120) must be adjusted as the exhaust gas flow rate and carbon dioxide concentration change even if the total amount of carbon dioxide flowing into the absorption tower (120) is constant.

If the liquid-gas ratio (L/G) of the absorption tower (120) is not controlled, the carbon dioxide removal rate in the absorption tower (120) fluctuates, and the absorption rate of carbon dioxide for the absorbent also changes, so the flow rate of steam flowing into the reheater (180) must also be controlled. Due to such fluctuations, the flow rate of carbon dioxide produced in the stripping tower (150) may fluctuate until the control of the equipment is stabilized.

Therefore, in order to maintain the production amount of carbon dioxide produced in the above-mentioned stripping tower (150) constant, the liquid-gas ratio (L/G) of the absorption tower (120) must be adjusted as the exhaust gas flow rate and carbon dioxide concentration change even if the total amount of carbon dioxide flowing into the absorption tower (120) is constant.

To this end, the wet carbon dioxide capture facility with recirculating absorbent according to an embodiment of the present invention can re-introduce the carbon dioxide rich absorbent into the absorption tower (120) through the recirculation pipe (210).

The above recirculation pipe (210) branches off from the first pipe (130) and is connected to the absorption tower (120), so that the carbon dioxide rich absorbent moving through the first pipe (130) through the recirculation pipe (210) can be re-introduced into the absorption tower (120).

When the exhaust gas flow rate and carbon dioxide concentration in the above pretreatment facility (110) change and the exhaust gas flows into the absorption tower (120), the liquid-gas ratio (L/G) of the absorption tower (120) changes, so carbon dioxide may not be sufficiently absorbed by the absorbent.

In this case, as the carbon dioxide rich absorbent moving through the first pipe (130) through the recirculation pipe (210) is re-introduced into the absorption tower (120), the liquid-gas ratio (L/G) of the absorption tower (120) is increased, so that carbon dioxide can be absorbed even in the carbon dioxide rich absorbent that has not fully absorbed carbon dioxide.

Referring to FIG. 2, the recirculation pipe (210) according to one embodiment of the present invention may be connected to the absorption tower (120) by branching from the first pipe (130) connecting the absorption tower (120) and the first rich solution pump (131). That is, the recirculation pipe (210) may be connected to the absorption tower (120) by branching from the front end of the first rich solution pump (131).

According to an embodiment of the present invention, the recirculation pipe (210) may be equipped with a second rich solution pump (211) that provides power to move the carbon dioxide rich absorbent to the absorption tower (120).

The second rich solution pump (211) can provide power to the carbon dioxide rich absorbent that flows into the absorption tower (120) through the recirculation pipe (210), and a portion of the carbon dioxide rich absorbent that is transported to the first rich solution pump (131) can be re-introduced into the absorption tower (120) through the second rich solution pump (211).

A wet carbon dioxide capture facility with recirculating absorbent according to an embodiment of the present invention may further include a rich analyzer (220) capable of measuring at least one of pH, viscosity, and specific gravity of the carbon dioxide rich absorbent collected at the bottom of the absorption tower (120), and a control unit (230) that controls the operation of the first rich solution pump (131) and the second rich solution pump (211).

Referring to FIGS. 2 and 4, the rich analyzer (220) can measure at least one of pH, viscosity, and specific gravity of the carbon dioxide rich absorbent collected at the bottom of the absorption tower (120). The rich analyzer (220) can be installed at various locations as long as it can measure at least one of pH, viscosity, and specific gravity of the carbon dioxide rich absorbent collected at the bottom of the absorption tower (120).

When the exhaust gas flow rate and carbon dioxide concentration in the above pretreatment facility (110) change and the exhaust gas flows into the absorption tower (120), the exhaust gas is absorbed by the carbon dioxide lean absorbent and collected at the bottom of the absorption tower (120). Here, the carbon dioxide lean absorbent absorbs carbon dioxide and becomes a carbon dioxide rich absorbent and is collected at the bottom of the absorption tower (120).

Since the exhaust gas conditions flowing into the absorption tower (120) change while the load of the gas turbine changes, the carbon dioxide absorption rate of the carbon dioxide rich absorbent accumulated at the bottom of the absorption tower (120) also changes.

At this time, since it is difficult to directly check the carbon dioxide absorption rate in real time, the carbon dioxide absorption rate can be measured through the rich analyzer (220) capable of measuring at least one of the pH, viscosity, and specific gravity of the carbon dioxide rich absorbent.

If carbon dioxide is not sufficiently absorbed into the carbon dioxide rich absorbent, the pH, viscosity, or specific gravity of the carbon dioxide rich absorbent may fall below a certain level. The rich analyzer (220) can measure this, and the absorption rate of carbon dioxide can be indirectly measured through the rich analyzer (220).

Referring to FIG. 4, the control unit (230) controls the operation of the first rich solution pump (131) and the second rich solution pump (211) according to the measurement value of the rich analyzer (220).

The above control unit (230) can control the operation of the first rich solution pump (131) and the second rich solution pump (211) according to the measurement value of the rich analyzer (220) to control the amount of carbon dioxide rich absorbent re-introduced into the absorption tower (120).

By controlling the amount of carbon dioxide rich absorbent re-introduced into the absorption tower (120) through the control unit (230), the liquid-gas ratio (L/G) of the absorption tower (120) is increased, so that carbon dioxide can be absorbed even in the carbon dioxide rich absorbent that has not fully absorbed the carbon dioxide.

According to an embodiment of the present invention, it is preferable to apply a format in which the capacity of the first rich solution pump (131) and the second rich solution pump (211) can be varied by applying an inverter.

Referring to FIG. 3, the recirculation pipe (210) according to another embodiment of the present invention may be connected to the absorption tower (120) by branching from the first pipe (130) connecting the first rich solution pump (131) and the heat exchanger (140). That is, the recirculation pipe (210) may be connected to the absorption tower (120) by branching from the rear end of the first rich solution pump (131).

According to an embodiment of the present invention, the recirculation pipe (210) may be provided with a first control valve (212) that controls the flow rate by opening and closing the recirculation pipe. In addition, the first pipe (130) connecting the first rich solution pump (131) and the heat exchanger (140) may be provided with a second control valve (132) that controls the flow rate by opening and closing the first pipe (130).

A portion of the carbon dioxide rich absorbent transferred to the first rich solution pump (131) can be re-introduced into the absorption tower (120) by the operation of the first control valve (212) and the second control valve (132).

A wet carbon dioxide capture facility with recirculating absorbent according to an embodiment of the present invention may further include a rich analyzer (220) capable of measuring at least one of pH, viscosity, and specific gravity of the carbon dioxide rich absorbent collected at the bottom of the absorption tower (120), and a control unit (230) that controls the operation of the first control valve (212) and the second control valve (132).

Referring to FIGS. 2 and 4, the rich analyzer (220) can measure at least one of pH, viscosity, and specific gravity of the carbon dioxide rich absorbent collected at the bottom of the absorption tower (120). The rich analyzer (220) can be installed at various locations as long as it can measure at least one of pH, viscosity, and specific gravity of the carbon dioxide rich absorbent collected at the bottom of the absorption tower (120).

When the exhaust gas flow rate and carbon dioxide concentration in the above pretreatment facility (110) change and the exhaust gas flows into the absorption tower (120), the exhaust gas is absorbed by the carbon dioxide lean absorbent and collected at the bottom of the absorption tower (120). Here, the carbon dioxide lean absorbent absorbs carbon dioxide and becomes a carbon dioxide rich absorbent and is collected at the bottom of the absorption tower (120).

Since the exhaust gas conditions flowing into the absorption tower (120) change while the load of the gas turbine changes, the carbon dioxide absorption rate of the carbon dioxide rich absorbent accumulated at the bottom of the absorption tower (120) also changes.

At this time, since it is difficult to directly check the carbon dioxide absorption rate in real time, the carbon dioxide absorption rate can be measured through the rich analyzer (220) capable of measuring at least one of the pH, viscosity, and specific gravity of the carbon dioxide rich absorbent.

If carbon dioxide is not sufficiently absorbed into the carbon dioxide rich absorbent, the pH, viscosity, or specific gravity of the carbon dioxide rich absorbent may fall below a certain level. The rich analyzer (220) can measure this, and the absorption rate of carbon dioxide can be indirectly measured through the rich analyzer (220).

Referring to FIG. 4, the control unit (230) controls the operation of the first control valve (212) and the second control valve (132) according to the measurement value of the rich analyzer (220).

The above control unit (230) can control the operation of the first control valve (212) and the second control valve (132) according to the measurement value of the rich analyzer (220) to control the amount of carbon dioxide rich absorbent re-introduced into the absorption tower (120).

By controlling the amount of carbon dioxide rich absorbent re-introduced into the absorption tower (120) through the control unit (230), the liquid-gas ratio (L/G) of the absorption tower (120) is increased, so that carbon dioxide can be absorbed even in the carbon dioxide rich absorbent that has not fully absorbed the carbon dioxide.

When the carbon dioxide rich absorbent is reintroduced into the absorption tower (120) by the operation of the first control valve (212) and the second control valve (132) according to an embodiment of the present invention, it is preferable that the first rich solution pump (131) has a larger capacity than a conventional rich solution pump (31).

In addition, when the carbon dioxide rich absorbent is reintroduced into the absorption tower (120) according to the operation of the first control valve (212) and the second control valve (132) according to an embodiment of the present invention, the control unit (230) can control the amount of the carbon dioxide rich absorbent reintroduced into the absorption tower (120) by controlling the opening rate of the first control valve (212) and the second control valve (132).

According to an embodiment of the present invention, the control unit (230) can also control the amount of steam that supplies heat to the reheater (180). The control unit (230) can control the amount of steam that supplies heat to the reheater (180) according to the measured value of the rich analyzer (220), thereby making it possible to maintain the production amount of carbon dioxide produced in the stripping tower (150) at a constant level.

According to an embodiment of the present invention, the point at which the recirculation pipe (210) is connected in the absorption tower (120) may be lower than the point at which the second pipe (160) is connected to the absorption tower (120).

Specifically, it is preferable that the injection position where the carbon dioxide rich absorbent is reintroduced into the absorption tower (120) through the recirculation pipe (210) be lower than the injection position where the carbon dioxide lean absorbent is injected into the absorption tower (120) through the second pipe (160).

Since the reaction in the above absorption tower (120) is a countercurrent contact, it is desirable for the exhaust gas to come into contact with a carbon dioxide lean absorbent that absorbs as little carbon dioxide as possible before being discharged from the absorption tower (120).

Therefore, it is preferable that the carbon dioxide rich absorbent reintroduced into the absorption tower (120) through the recirculation pipe (210) be reintroduced from below the carbon dioxide lean absorbent reintroduced into the absorption tower (120) through the second pipe (160).

The wet carbon dioxide capture facility with recirculating absorbent according to the embodiment of the present invention described above has the following effects.

A wet carbon dioxide capture facility with recirculating absorbent according to an embodiment of the present invention has an advantage in that the flow rate of carbon dioxide produced in a stripping tower can be maintained constant even if the concentration and flow rate of carbon dioxide flowing into the wet carbon dioxide capture facility fluctuate by reintroducing a portion of the circulated absorbent into the absorption tower to increase the amount of carbon dioxide absorbed in the absorption tower.

The wet carbon dioxide capture facility with recirculating absorbent according to an embodiment of the present invention has an advantage in that it can stably operate a compression facility system operated with carbon dioxide discharged from a stripping tower by maintaining the flow rate of carbon dioxide produced in a stripping tower constant even when the concentration and flow rate of carbon dioxide flowing into the wet carbon dioxide capture facility change.

In addition, the wet carbon dioxide capture facility with recirculating absorbent according to an embodiment of the present invention has an advantage in that it can maximize the carbon dioxide absorption rate of the carbon dioxide-rich absorbent by recycling a portion of the carbon dioxide-rich absorbent that has absorbed carbon dioxide in the absorption tower to increase the liquid-gas ratio (L/G) in the absorption tower, thereby reducing the amount of heat energy or steam required for carbon dioxide separation in the stripping tower.

In addition, the wet carbon dioxide capture facility with recirculating absorbent according to an embodiment of the present invention has the advantage of being able to control the flow rate of exhaust gas flowing into the carbon dioxide capture facility according to the concentration of carbon dioxide through a carbon dioxide analyzer capable of measuring the carbon dioxide concentration of exhaust gas in real time and a flow rate control valve capable of controlling the flow rate of exhaust gas.

Although the present invention has been described with reference to one embodiment shown in the drawings, this is merely exemplary, and those skilled in the art will understand that various modifications and variations of embodiments are possible from this. Therefore, the true technical protection scope of the present invention should be determined by the technical idea of the appended patent claims.

110...Pretreatment equipment 111...Suction fan
112...Supply piping 113...Flow control valve
114...Flowmeter 115...Carbon dioxide analyzer
116...??Ching Tower 117...Return Pipe
120...Absorption tower 130...1st pipe
131...1st rich solution pump 132...2nd regulating valve
140...Heat exchanger 150...Removal tower
160...2nd pipe 161...Lin solution pump
170...Condenser 171...Reflux drum
180...Reheater 181...Condensate Tank
210...Recirculation pipe 211...Second rich solution pump
212...First control valve 220...Rich analyzer
230...Control Unit

Claims (13)

In a carbon dioxide capture facility for capturing carbon dioxide contained in exhaust gas,
Pretreatment equipment for removing sulfur compounds contained in the exhaust gas or lowering the temperature of the exhaust gas;
An inlet pipe through which the exhaust gas treated in the above pretreatment facility moves;
An absorption tower in which the exhaust gas is introduced through the inlet pipe and the carbon dioxide contained in the exhaust gas is reacted with an absorbent;
A first pipe through which the carbon dioxide rich absorbent, which has reacted with the carbon dioxide and the absorbent, moves;
A heat exchanger provided in the first pipe and in which heat exchange of the carbon dioxide rich absorbent is performed;
A stripping tower into which the carbon dioxide rich absorbent is introduced and carbon dioxide is separated from the carbon dioxide rich absorbent;
A second pipe connecting the above-mentioned stripping tower and the above-mentioned absorption tower, through which the carbon dioxide lean absorbent from which the carbon dioxide is separated moves;
A recirculation pipe branched from the first pipe and connected to the absorption tower;
The carbon dioxide rich absorbent moving through the recirculation pipe to the first pipe is re-introduced into the absorption tower,
The above pretreatment facility is,
It includes a flow control valve that controls the flow rate of the exhaust gas flowing into the absorption tower.
The above pretreatment facility includes a supply fan that moves exhaust gas,
The above flow control valve is installed in the return pipe connecting the front and rear ends of the supply fan.
The first pipe is provided with a first rich solution pump that provides power to move the carbon dioxide rich absorbent.
The above recirculation pipe is connected to the absorption tower by branching from the first pipe connecting the first rich solution pump and the heat exchanger,
The above recirculation pipe is provided with a first control valve for opening and closing the above recirculation pipe.
A wet carbon dioxide capture facility with recirculating absorbent, characterized in that the first pipe connecting the first rich solution pump and the heat exchanger is provided with a second control valve for opening and closing the first pipe. delete In the first paragraph,
The above pretreatment facility is,
Includes a flow meter capable of measuring the flow rate of the above exhaust gas,
A wet carbon dioxide capture facility with recirculating absorbent, characterized in that the above flow control valve is opened and closed according to the flow rate measured by the above flow meter. delete In the third paragraph,
The above pretreatment facility is,
A wet carbon dioxide capture facility with recirculating absorbent, characterized in that it includes a carbon dioxide analyzer for measuring the concentration of carbon dioxide contained in the exhaust gas. In the first paragraph,
The first pipe is provided with a first rich solution pump that provides power to move the carbon dioxide rich absorbent.
A wet carbon dioxide capture facility with recirculating absorbent, characterized in that the recirculation pipe is connected to the absorption tower while branching from the first pipe connecting between the absorption tower and the first rich solution pump. In Article 6,
In the above recirculation pipe,
A wet carbon dioxide capture plant with recirculating absorbent, characterized in that it is provided with a second rich solution pump that provides power to move the carbon dioxide rich absorbent to the absorption tower. In Article 7,
A rich analyzer capable of measuring at least one of pH, viscosity, and specific gravity of the carbon dioxide rich absorbent collected at the bottom of the above absorption tower,
It further includes a control unit that controls the operation of the first rich solution pump and the second rich solution pump,
A wet carbon dioxide capture facility with recirculating absorbent, characterized in that the control unit controls the operation of the first rich solution pump and the second rich solution pump according to the measurement value of the rich analyzer. delete delete delete In the first paragraph,
A rich analyzer capable of measuring at least one of pH, viscosity, and specific gravity of the carbon dioxide rich absorbent collected at the bottom of the above absorption tower,
It further includes a control unit that controls the operation of the first control valve and the second control valve,
A wet carbon dioxide capture facility with recirculating absorbent, characterized in that the control unit controls the operation of the first control valve and the second control valve according to the measurement value of the rich analyzer. In the first paragraph,
The point where the recirculation pipe is connected in the above absorption tower is,
A wet carbon dioxide capture facility with recirculating absorbent, characterized in that the second pipe is at a lower point than the point at which it is connected to the absorption tower.

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