System for carbon dioxide capture during steelmaking process

Abstract

The present invention provides a system capable of recovering, for utilization in carbon dioxide capture, intermediate-temperature off-gas included in off-gas generated during a steelmaking process, and achieving high electricity productivity against the same input gas by supplying high-temperature and high-pressure off-gas to a TRP.

Description

Steelmaking process carbon dioxide capture system

[0001] The present invention relates to a carbon dioxide capture system for a steelmaking process that can maximize power generation and minimize energy consumption by utilizing off-gas generated during the steelmaking process, while simultaneously improving the efficiency of carbon dioxide capture during the steelmaking process and minimizing heat loss during the carbon dioxide capture process.

[0002]

[0003] Pressure Swing Adsorption (PSA) is primarily used to remove CO2 in order to improve the energy efficiency of the steelmaking process and the utilization rate of reducing gases (carbon monoxide, hydrogen) in byproduct gases.

[0004] The above PSA (80) process is a method that utilizes the adsorption pressure difference of a gas using an adsorbent, and has the advantage of low energy consumption and easy operation.

[0005] Accordingly, in the existing steelmaking process, some of the off-gas generated in the fluidized bed furnace (10) is compressed by a compressor (70) before being introduced into the PSA (80) process, and then introduced into the PSA (80) process.

[0006] Currently, some of the off-gas generated in the steelmaking process is supplied to a TRP (Top Gas Recovery Plant) to produce electricity before being supplied as fuel to a power plant, and the rest is processed by removing carbon dioxide through a PSA (80) process and then re-supplying it to a fluidized bed (10).

[0007] However, it has been consistently pointed out that the above off-gas contains not only carbon dioxide but also a large amount of other gases such as carbon monoxide and hydrogen, and that the compressor (70) compresses unnecessary gases before supplying the off-gas to the PSA (80) process, causing an overload.

[0008] In addition, it is pointed out as a problem that in the current off-gas treatment process, the off-gas must be distributed to the TRP (60) and PSA (80) processes, so as the amount of gas distributed to the PSA (80) process increases, the amount of electricity produced in the TRP (60) decreases.

[0009] In addition, the above off-gas is generated at a high temperature and contains many impurities, so a dry dust collector (40) or a wet dust collector (50) is used to remove them. However, in the case of the wet dust collector (50), the phenomenon in which the off-gas is cooled during the filtration process, resulting in the waste of sensible heat, is also pointed out as one of the challenges that must be overcome.

[0010] In addition, a method is currently used to obtain high-temperature steam by heat-exchanging the high-temperature off-gas generated in the above-mentioned fluid flow path (10) with the first heat exchanger (30), but it is pointed out as a problem that even after going through the above process, the off-gas maintains a high temperature of 200 °C or higher, so the wasted heat cannot be fully utilized in terms of thermal energy utilization.

[0011] As another problem, if the off-gas is lowered to a low temperature as described above, the volume of the off-gas to drive the TRP (60) is also reduced relative to the same mass of off-gas, which may result in a decrease in power generation.

[0012] In addition, carbon dioxide captured through the existing PSA (80) method is difficult to satisfy the minimum carbon dioxide concentration (95% or more) required to be linked to CCS (Carbon Capture and Storage), and in order to satisfy the above conditions, additional equipment such as additional PSA (80) processes is required, so the problem of overall production efficiency being reduced may occur.

[0013] Prior art 1 (Registered Patent 10-135395) disclosed prior to the present application is also based on a method for removing carbon dioxide using the above PSA (80) method, and therefore cannot solve the problem described above.

[0014] Similarly, prior art 2 (registered patent 10-1948991) disclosed prior to the present application is also based on the same configuration as prior art 1 and therefore fails to provide a solution.

[0015] Therefore, it is absolutely necessary to develop a new technology that can replace the existing PSA (80) method used to remove carbon dioxide generated in the steelmaking process and minimize the energy required for carbon dioxide capture efficiency.

[0016]

[0017] The present invention has been devised to solve the aforementioned problems and provides a method for utilizing the heat of medium-temperature off-gas for carbon dioxide capture, in addition to the heat used to produce high-temperature steam among the high-temperature off-gas generated in the steelmaking process.

[0018] In addition, it provides a method to secure a higher power production rate compared to the existing flow rate and the same gas weight by supplying a large amount of off-gas to the TRP at a higher temperature and high pressure than the current process.

[0019] Additionally, a method is provided to reduce unnecessary energy consumed by the compressor (70) by reducing the flow rate of the off-gas compressed before being supplied to the PSA (80).

[0020] In addition, it provides a method to improve the carbon dioxide removal rate by capturing carbon dioxide in the off-gas produced in the fluidized bed, which was previously supplied directly to the power plant.

[0021] In addition, it provides a method to minimize maintenance costs by simplifying the existing process of capturing and concentrating carbon dioxide contained in off-gas.

[0022]

[0023] The objects of the present invention are not limited to those mentioned above, and other unmentioned objects and advantages of the present invention may be understood from the following description and will be more clearly understood by the embodiments of the present invention. Furthermore, it will be readily apparent that the objects and advantages of the present invention can be realized by the means and combinations thereof set forth in the claims.

[0024]

[0025] To solve the above-mentioned problem, the present invention comprises, in a steelmaking process using a fluidized bed furnace (10) and a melting furnace (20), a first pipe (L1) for delivering a first gas generated during the operation of the fluidized bed furnace (10) to a power plant (1); a first heat exchanger (30), a dry dust collector (40), a second heat exchanger (35), a wet dust collector (50), and a TRP (60) sequentially interposed in the first pipe (L1); a second pipe (L2) branched from the first pipe (L1) between the wet dust collector (50) and the TRP (60) and connected to the fluidized bed furnace (10); a carbon dioxide collector (100) interposed in the second pipe (L2) for capturing carbon dioxide; and a third pipe (L3) for delivering medium-temperature steam produced in the second heat exchanger (35) to the carbon dioxide collector (100). It may include a fourth pipe (L4) that delivers carbon dioxide collected from the carbon dioxide collector (100) to a carbon dioxide storage tank (200); and a first compressor (70) that is interposed in the second pipe (L2) at the rear end of the carbon dioxide collector (100) to compress the second gas from which carbon dioxide has been removed from the first gas and supply it to the flow path (10).

[0026] In one embodiment of the present invention, the carbon dioxide capturer (100) may be characterized by being composed of an absorber (110) that absorbs carbon dioxide from the first gas into an ammonia solution and a regenerator (120) that is connected to the third pipe (L3) and separates carbon dioxide from the ammonia solution containing carbon dioxide using medium-temperature steam.

[0027] In one embodiment of the present invention, the second heat exchanger (35) and the wet dust collector (50) may be characterized by being interposed in a second pipe (L2) located upstream of the carbon dioxide collector (100).

[0028] In one embodiment of the present invention, the wet dust collector (50) may be characterized by being interposed in a second pipe (L2) located upstream of the carbon dioxide collector (100).

[0029] In one embodiment of the present invention, a fifth pipe (L5) is installed to transfer a third high-temperature gas generated during the operation of the melting furnace (20) to the carbon dioxide collector (100), and a high-temperature dust collector (90) and a wet dust collector (50) are sequentially interposed in the fifth pipe (L5).

[0030] In one embodiment of the present invention, the second compressor (130) may be interposed in the fourth pipe (L4).

[0031] In one embodiment of the present invention, the fourth pipe (L4) may be characterized as being connected to a carbon dioxide storage tank.

[0032] In one embodiment of the present invention, the carbon dioxide capture device (100) may be characterized by separating carbon dioxide from the first gas using at least one of an amine or an inorganic salt.

[0033] To solve the above-mentioned problem, the present invention comprises, in a steelmaking process using a fluidized bed furnace (10) and a melting furnace (20), a first step of passing a first high-temperature gas generated during the operation of the fluidized bed furnace (10) through a second heat exchanger (35) to obtain medium-temperature steam and cooling it to a second temperature; a second step of filtering impurities contained in the first gas that has passed through the first step using a wet dust collector (50) and raising it to a third temperature; a third step of guiding a portion of the first gas that has passed through the second step to a carbon dioxide collector (100); a fourth step of supplying the medium-temperature steam produced in the first step to the carbon dioxide collector (100); and a fifth step of capturing carbon dioxide contained in the first gas with an ammonia solution in the carbon dioxide collector (100) and separating the carbon dioxide with the medium-temperature steam. The method may include a sixth step of supplying the second gas, from which carbon dioxide has been removed from the first gas in the fifth step, to the flow path (10).

[0034] In one embodiment of the present invention, the first gas that was not supplied to the carbon dioxide capture device (100) in the third step may be supplied to the TRP (60) to produce electricity.

[0035] In one embodiment of the present invention, the carbon dioxide captured in the fifth step may be supplied to a power plant (1) or supplied to a carbon dioxide storage facility.

[0036] In one embodiment of the present invention, the first gas in the first step passes through a first heat exchanger (30) to obtain high-temperature steam and is cooled to a first temperature, and the first gas passes through a dry dust collector (40) and then passes through a second heat exchanger (35).

[0037] In one embodiment of the present invention, the method may be characterized by including a step of guiding a third gas of high temperature generated during the operation of the melting furnace (20) to the carbon dioxide capture device (100).

[0038] In one embodiment of the present invention, the third gas may be characterized by passing through a high-temperature dust collector (90) to filter out impurities first, and then passing through a wet dust collector (50) to filter out impurities second and simultaneously raise the temperature to a third temperature, and then being guided to the carbon dioxide collector (100).

[0039] In one embodiment of the present invention, the carbon dioxide capturer (100) may be characterized by capturing carbon dioxide through the steps of adsorbing carbon dioxide from the first gas onto an ammonia solution and exposing the medium-temperature steam to the ammonia solution to extract carbon dioxide.

[0040] In one embodiment of the present invention, the ammonia solution may be replaced with either an amine or an inorganic salt.

[0041] In one embodiment of the present invention, the first gas supplied to the TRP (60) may be characterized by being supplied through a wet dust collector (50).

[0042] To solve the above-mentioned problem, the present invention comprises, in a steelmaking process using a fluidized bed furnace (10) and a melting furnace (20), a first step of passing a first high-temperature gas generated during the operation of the fluidized bed furnace (10) through a first heat exchanger (30) to obtain high-temperature steam and raise it to a first temperature; a second step of filtering impurities contained in the first gas that has passed through the first step using a dry dust collector (40); a third step of passing a portion of the first gas at the first temperature that has passed through the second step through a second heat exchanger (35) to obtain medium-temperature steam and raise it to a second temperature; a fourth step of filtering impurities contained in the first gas at the second temperature that has passed through the third step using a wet dust collector (50) to raise it to a third temperature; and a fifth step of guiding the first gas that has passed through the fourth step to a carbon dioxide collector (100). The method may include a sixth step of supplying the medium-temperature steam produced in the third step to the carbon dioxide capturer (100); a seventh step of capturing carbon dioxide contained in the first gas with an ammonia solution in the carbon dioxide capturer (100) and separating the carbon dioxide with the medium-temperature steam; and an eighth step of supplying the second gas, from which carbon dioxide has been removed from the first gas in the seventh step, to the flow path (10).

[0043] In one embodiment of the present invention, the step of producing electricity by supplying the first gas that was not supplied to the carbon dioxide capture device (100) in the third step to the TRP (60) may be included.

[0044] In one embodiment of the present invention, the method may be characterized by including a step of guiding a third gas generated during the operation of the melting furnace (20) to the carbon dioxide capture device (100).

[0045] In one embodiment of the present invention, the third gas may be characterized by passing through a high-temperature dust collector (90) to filter out impurities contained in the third gas before being guided to the carbon dioxide collector (100), and passing through a wet dust collector (50) to filter out impurities remaining in the third gas and to raise it to a third temperature.

[0046] To solve the above-mentioned problem, the present invention comprises: a first step of passing a first high-temperature gas generated during the operation of the fluid flow path (10) through a first heat exchanger (30) to obtain high-temperature steam and raise it to a first temperature; a second step of filtering impurities contained in the first gas that has passed through the first step using a dry dust collector (40); a third step of passing the first gas that has passed through the second step through a second heat exchanger (35) to obtain medium-temperature steam and raise it to a second temperature; a fourth step of guiding a portion of the first gas that has passed through the third step to a carbon dioxide collector (100); a fifth step of supplying the medium-temperature steam produced in the third step to the carbon dioxide collector (100); and a sixth step of capturing carbon dioxide contained in the first gas with an ammonia solution in the carbon dioxide collector (100) and separating the carbon dioxide with the medium-temperature steam. The method may include a seventh step of supplying the second gas, from which carbon dioxide has been removed from the first gas in the sixth step, to the flow path (10).

[0047] In one embodiment of the present invention, the step of supplying the first gas that was not supplied to the carbon dioxide capture device (100) in the fourth step to the TRP (60) to produce electricity may be included.

[0048] In one embodiment of the present invention, the method may be characterized by including a step of guiding a third gas of high temperature generated during the operation of the melting furnace (20) to the carbon dioxide capture device (100).

[0049] In one embodiment of the present invention, the third gas may be characterized by passing through a high-temperature dust collector (90) to filter out impurities first, and then passing through a wet dust collector (50) to filter out impurities second and simultaneously raise the temperature to a third temperature, and then being guided to the carbon dioxide collector (100).

[0050] In one embodiment of the present invention, the first temperature may be higher than the second temperature, and the second temperature may be higher than the third temperature.

[0051]

[0052] According to various embodiments of the present invention, economic efficiency can be improved by recovering the heat contained in medium-temperature off-gases discarded in the steelmaking process and utilizing it for carbon dioxide capture.

[0053] According to various embodiments of the present invention, high-temperature, high-pressure off-gas is supplied to the TRP, thereby enabling high electrical productivity compared to the same input gas.

[0054] According to various embodiments of the present invention, the overall steelmaking process cost can be made more efficient by minimizing the compression energy used to remove carbon dioxide contained in the off-gas.

[0055] According to various embodiments of the present invention, carbon dioxide contained in off-gas can be removed more completely than conventional methods, thereby contributing to the global goal of carbon neutrality.

[0056] According to various embodiments of the present invention, connectivity with CCUS can be enhanced by collecting carbon dioxide contained in off-gas at a high concentration.

[0057] According to various embodiments of the present invention, the positions of the components can be freely changed according to user purposes, such as increasing power production, producing concentrated carbon dioxide, or securing steam energy, to carry out a carbon dioxide removal process from off-gas generated during the steelmaking process.

[0058]

[0059] Figure 1 is a schematic diagram showing a system for removing carbon dioxide from off-gas generated in a fluidized bed furnace or melting furnace in a conventional steelmaking process.

[0060] FIG. 2 is a schematic diagram showing a system for removing carbon dioxide in off-gas using medium-temperature steam according to a first embodiment of the present invention.

[0061] FIG. 3 is a schematic diagram showing a system for removing carbon dioxide in off-gas using medium-temperature steam according to a second embodiment of the present invention.

[0062] FIG. 4 is a schematic diagram showing a system for removing carbon dioxide in off-gas using medium-temperature steam according to a third embodiment of the present invention.

[0063] FIG. 5 is a schematic diagram showing a system for removing carbon dioxide in off-gas using medium-temperature steam according to the fourth embodiment of the present invention.

[0064] FIG. 6 is a schematic diagram showing a system for removing carbon dioxide in off-gas using medium-temperature steam according to the fifth embodiment of the present invention.

[0065] FIG. 7 is a system diagram showing the configuration of a carbon dioxide capture device according to an embodiment of the present invention.

[0066]

[0067] The advantages and features of the present invention and the methods for achieving them will become clear by referring to the embodiments described below in detail together with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below but may be implemented in various different forms. These embodiments are provided merely to ensure that the disclosure of the present invention is complete and to fully inform those skilled in the art of the scope of the invention, and the present invention is defined only by the scope of the claims. Throughout the specification, the same reference numerals refer to the same components.

[0068] Although terms such as "first," "second," etc., are used to describe various components, it goes without saying that these components are not limited by these terms. These terms are used merely to distinguish one component from another, and unless specifically stated otherwise, the first component may also be the second component.

[0069] Throughout the specification, unless specifically stated otherwise, each component may be singular or plural.

[0070] In the following, the statement that any configuration is placed on the "upper (or lower)" of a component or on the "upper (or lower)" of a component may mean not only that any configuration is placed in contact with the upper (or lower) surface of said component, but also that another configuration may be interposed between said component and any configuration placed on (or below) said component.

[0071] In addition, where it is stated that one component is "connected," "combined," or "connected" to another component, it should be understood that while the components may be directly connected or connected to each other, another component may be "interposed" between each component, or each component may be "connected," "combined," or "connected" through another component.

[0072] Singular expressions used in this specification include plural expressions unless the context clearly indicates otherwise. In this application, terms such as "composed of" or "comprising" should not be interpreted as necessarily including all of the various components or steps described in the specification, and should be interpreted as meaning that some of the components or steps may be omitted or additional components or steps may be included.

[0073] Throughout the specification, "A and / or B" means A, B, or A and B unless specifically stated otherwise, and "C to D" means C or more and D or less unless specifically stated otherwise.

[0074]

[0075] Hereinafter, a carbon dioxide capture system in a steelmaking process according to various embodiments will be described with reference to the attached drawings.

[0076]

[0077] FIG. 1 illustrates a system configuration used to remove carbon dioxide in off-gas generated during operation in a fluidized bed furnace (10) and a melting furnace (20) in a conventional steelmaking process.

[0078] The above existing steelmaking processes can be broadly classified into blast furnace methods, electric furnace methods, and FINEX methods.

[0079] The carbon dioxide removal system of the present invention can be used in all of the above-mentioned steelmaking processes, but below it can be preferably applied to the FINEX steelmaking process, where low-grade iron ore and low-grade general iron ore are used and the amount of carbon dioxide generated may be excessive depending on the management conditions.

[0080] However, it is obvious that the scope of the present invention is not limited to the FINEX steelmaking process for carbon dioxide capture methods.

[0081] The existing carbon dioxide capture method using PSA (80) always required supplying off-gas at a pressure of at least a certain level (about 5 bar), but while the above method has the advantage of being relatively simple in terms of equipment, it has the disadvantage that the amount of power that can be produced decreases as the flow rate of off-gas supplied to the PSA (80) increases while the flow rate of off-gas flowing into the TRP (60) decreases.

[0082] In addition, there was also a disadvantage that the temperature of the off-gas discharged from the above flow path (10), which is about 400 degrees or higher, had to be lowered to about 30 degrees considering the lifespan of the above compressor (70), and thus the heat energy loss resulting therefrom was enormous.

[0083] In addition, the limitations of existing carbon dioxide removal processes are as described above.

[0084]

[0085] [First Example]

[0086] FIGS. 2 and 6 illustrate the configurations required for a first embodiment for removing carbon dioxide in off-gas generated during operation in a fluidized bed furnace (10) and a melting furnace (20) in a steelmaking process proposed in the present invention.

[0087] In the first embodiment, the off-gas produced in the flow path (10) in the process can be transported to the power plant (1) along the first pipe (L1).

[0088] The off-gas generated during the operation of the above-mentioned fluid path (10) contains carbon dioxide (CO2), nitrogen (N2), carbon monoxide (CO), hydrogen (H2), dust, and naphthalene (C 10 It includes H8, etc., and since the ratio of its components may vary depending on the composition of the supplied raw iron or coal, it is referred to as the first gas in this application.

[0089] Also, for the same reason, the off-gas generated during the operation of the melting furnace (20) is named the third gas.

[0090] The above power plant (1) can produce electricity by burning carbon monoxide (CO) and hydrogen (H2), etc., among the above first gases.

[0091] A first heat exchanger (30) may be interposed in the first pipe (L1) above.

[0092] The first heat exchanger (30) can perform the function of obtaining high-temperature steam from high-temperature off-gas (about 400 degrees or higher) produced in the fluid flow path (10) and cooling the off-gas to a first temperature.

[0093] The above high-temperature steam can be utilized as energy to drive equipment required during the steelmaking process.

[0094] The first gas cooled to the first temperature can be filtered by passing through a dry dust collector (40) interposed in the first pipe (L1) to remove fine dust or impurities inside.

[0095] The above dry dust collector (40) can be a commercial bag filter, etc.

[0096] A second heat exchanger (35) may be interposed on the first pipe (L1), and the first gas passing through the dry dust collector (40) produces medium-temperature steam while passing through the second heat exchanger (35), and in the process, the first gas may be cooled to a second temperature.

[0097] The first gas cooled to the second temperature can also be passed through a wet dust collector (50) interposed in the first pipe (L1) to remove tar and naphthalene components contained therein.

[0098] At this time, the above wet dust collector (50) may be a wet dust collector, and at least one of a water-flow type, a pressurized water type, or a rotary type may be used.

[0099] As the first gas passes through the wet dust collector (50), heat exchange with the cooling water inevitably occurs, so it can be cooled back to the third temperature.

[0100] Since the above-described first temperature, second temperature, and third temperature may vary depending on the scale or usage environment of the steelmaking process, in this application, the first temperature is lower than the high-temperature off-gas produced in the fluidized bed furnace (10) or melting furnace (20), the second temperature is lower than the first temperature, and the third temperature is lower than the second temperature, having a relative meaning.

[0101] The first gas that passes through the above wet dust collector (50) is delivered to the TRP (60) along the above first pipe (L1) and can generate electricity by rotating the installed turbine.

[0102] A second pipe (L2) can be branched from the first pipe (L1) between the wet dust collector (50) and the TRP (60) and connected to the flow path (10).

[0103] Accordingly, some of the first gas that has passed through the wet dust collector (50) can flow along the second pipe (L2).

[0104] A carbon dioxide collector (100) may be interposed in the second pipe (L2) above.

[0105] The carbon dioxide collector (100) removes carbon dioxide from the first gas to produce a second gas, and then sends it to the flow path (10) through the second pipe (L2), and the carbon dioxide collected from the first gas by the carbon dioxide collector (100) can be transferred to the carbon dioxide storage (200) through the fourth pipe (L4).

[0106] The above carbon dioxide storage facility may be a gas tank, a ship, underground, or the seabed.

[0107] The above carbon dioxide capture device (100) may be composed of an absorber (110) and a regenerator (120).

[0108] The absorber (110) is a device that absorbs carbon dioxide contained in the first gas flowing into the second pipe (L2) into an ammonia solution, and depending on the process environment, at least one of an amine or an inorganic salt may be used for the ammonia.

[0109] The second gas, from which carbon dioxide in the first gas has been removed by passing through the absorber (110), can be supplied to the flow path (10) along the second pipe (L2).

[0110] The above ammonia solution containing carbon dioxide may be transferred to the regenerator (120).

[0111] One side of the regenerator (120) is connected to the second heat exchanger (35) and the third pipe (L3), so that the second heat exchanger (35) can transfer medium-temperature steam obtained from the first gas to the regenerator (120).

[0112] The carbon dioxide dissolved in the ammonia solution inside the regenerator (120) can be separated into carbon dioxide and ammonia solution by being exposed to medium-temperature steam delivered to the third pipe (L3).

[0113] The carbon dioxide capture method using the above ammonia, amine, or inorganic salt has the advantage of being able to stably capture more than 90% regardless of the carbon dioxide concentration or specific gravity in the first gas compared to the method using the existing PSA (80).

[0114] However, the above method has limitations in that it requires a separate heat source to separate carbon dioxide from the solution in which carbon dioxide is dissolved, so it has not been used. But when the carbon dioxide extraction system proposed in this application is applied, the remaining heat of the first gas that was previously wasted is converted into medium-temperature steam through the second heat exchanger (35) and extracted and used, thereby overcoming these limitations.

[0115] As illustrated in FIG. 7, the fourth pipe (L4) may be installed on one side of the regenerator (120), and a second compressor (130) may be interposed in the fourth pipe (L4) downstream of the regenerator (120).

[0116] The second compressor (130) provides power to transport the extracted carbon dioxide to the carbon dioxide storage (200) located at a distance.

[0117] For the same reason, a first compressor (70) may be interposed in the second pipe (L2) downstream of the absorber (110) of the carbon dioxide collector (100).

[0118] Since the first compressor (70) and the second compressor (130) above perform the function of increasing pressure to suit the purpose of gas transport and gas utilization, rather than providing the pressure required for carbon dioxide extraction from the existing PSA (80), it is acceptable to use one with a smaller capacity than the existing one.

[0119] This allows for a significant reduction in energy consumption compared to conventional compressors.

[0120]

[0121] [2nd Example]

[0122] FIG. 3 shows a configuration diagram of a second embodiment of the present invention.

[0123] In the case of the first embodiment above, the process of cooling the temperature of the first gas to a third temperature through the wet dust collector (50) before the TRP (60) is included.

[0124] In this case, as the actual volume of the first gas delivered to the same TRP (60) decreases due to cooling, the amount of electricity produced by the TRP (60) is naturally bound to decrease.

[0125] This second embodiment is proposed to overcome this, and the main structural difference from the first embodiment is that the second heat exchanger (35) and the wet dust collector (50), which were located on the first pipe (L1) in the first embodiment, are interposed on the second pipe (L2).

[0126] That is, the system can be configured such that the second pipe (L2) branches off from the first pipe (L1), the second heat exchanger (35) and the wet dust collector (50) are interposed in succession, and then the carbon dioxide collector (100) is located thereafter.

[0127] As in the first embodiment above, the second heat exchanger (35) can obtain medium-temperature steam from the first gas flowing into the second pipe (L2) and supply it to the regenerator (120) of the carbon dioxide collector (100) through the third pipe (L3).

[0128] The above second embodiment corresponds to a method that can maximize the electricity production of the TRP (60).

[0129] That is, since the first gas delivered to the TRP (60) has a first temperature, it has a larger volume relative to the same mass, so the turbine rotation speed can be increased.

[0130] In the first embodiment above, the first gas delivered to the TRP (60) had a third temperature, so the actual flow rate of the first gas for producing electricity was inevitably lower compared to the second embodiment.

[0131] Instead, the second heat exchanger must obtain medium-temperature steam by exchanging heat with a portion of the first gas branched into the second pipe (L2) rather than by exchanging heat with the first gas produced in the fluidized bed (10) to obtain medium-temperature steam, so the amount of carbon dioxide dissolved in the ammonia solution in the regenerator (120) of the carbon dioxide collector (100) that can be extracted may be insufficient compared to the first embodiment.

[0132] However, since the above wet dust collector (50) also filters some of the first gas branched off to the above second pipe (L2), it also has the advantage of reducing the energy used to drive the above wet dust collector (50).

[0133] Since the above first and second embodiments have contrasting advantages and disadvantages, the user may choose between them depending on the usage environment and the amount of first gas guided to the first pipe (L1) and the second pipe (L2).

[0134] The amount of first gas introduced into the first pipe (L1) and the second pipe (L2) can be controlled by the difference in cross-sectional area of ​​the pipes or by operating a valve installed at the branching point of the first pipe (L1) and the second pipe (L2).

[0135] In order to carry out the second embodiment above, there may also be a constraint that the dry dust collector (40) must filter out as much as possible the impurities in the first gas delivered to the TRP (60).

[0136]

[0137] [3rd Example]

[0138] FIG. 4 illustrates a configuration diagram of a third embodiment of the present invention.

[0139] The above third embodiment corresponds to a compromise embodiment regarding the advantages and disadvantages of the above first and second embodiments.

[0140] In this embodiment, a first heat exchanger (30), a dry dust collector (40), and a second heat exchanger (35) may be interposed in the first pipe (L1) upstream of the TRP (60).

[0141] In addition, a wet dust collector (50) may be interposed in front of the carbon dioxide collector (100) in the second pipe (L2).

[0142] Accordingly, the carbon dioxide capturer (100) receives medium-temperature steam obtained by the second heat exchanger (35) performing heat exchange on all first gases produced in the fluid flow path (10) as in the first embodiment through the third pipe (L3), so that carbon dioxide can be separated more efficiently from the ammonia solution in which carbon dioxide is dissolved in the regenerator (120).

[0143] Additionally, the first gas cooled to a second temperature through the second heat exchanger (35) is supplied to the TRP (60), so that the turbine can be driven more efficiently than when the first gas at a third temperature is supplied as in the first embodiment, thereby increasing the amount of electricity produced; however, compared to the second embodiment in which the first gas at the first temperature is supplied, the volume of the first gas is smaller relative to the same mass, so the amount of electricity produced may be smaller.

[0144] In this embodiment as well, since the first gas delivered to the TRP (60) is filtered only by the dry dust collector (40) as in the second embodiment, there is also a disadvantage that the TRP (60) turbine may be damaged if the first gas contains tar or naphthalene.

[0145] This embodiment corresponds to a compromise embodiment between the first embodiment and the second embodiment as described above.

[0146] For example, if the first embodiment above focuses on separating carbon dioxide from the first gas, the second embodiment can be described as an embodiment focused on rotating the TRP (60) turbine with the first gas generated in the fluid flow path (10) to produce maximum electricity.

[0147] Since carbon dioxide extraction and electricity production are both requirements for carbon neutrality, one of the above embodiments may be selected depending on the user's usage environment and priority field.

[0148]

[0149] [Fourth Example]

[0150] FIG. 5 illustrates a configuration diagram of the fourth embodiment of the present invention.

[0151] While the first to third embodiments above concern capturing carbon dioxide contained in the first gas generated in the fluidized bed (10), the present embodiment concerns capturing carbon dioxide from the off-gas, i.e., the third gas, generated during the operation of the melting bed (20), which is one of the essential components of the steelmaking process.

[0152] Therefore, the method for capturing carbon dioxide from the first gas produced in the above-mentioned fluid flow path (10) follows the first to third embodiments, so the explanation is omitted.

[0153] The third gas generated during the operation of the above melting furnace (20) can be transferred to the above power plant (1) through the sixth pipe (L6).

[0154] A high-temperature dust collector (90) and a wet dust collector (50) may be sequentially interposed in the above 6th pipe (L6).

[0155] Fine dust or impurities contained in the high-temperature third gas generated in the melting furnace (20) can be filtered through the high-temperature dust collector (90).

[0156] In addition, through the wet dust collector (50), the tar or naphthalene inside the third gas can be filtered, and at the same time, the third gas can be cooled to a third temperature.

[0157] In the conventional case, the third gas generated in the melting furnace (20) was transferred to the power plant (1) without a carbon dioxide capture process, but in this case, the reduction rate of carbon dioxide emissions in the entire steelmaking process is bound to be limited.

[0158] Accordingly, in this embodiment, in order to transfer the third gas to the carbon dioxide collector (100), the fifth pipe (L5) connected to the carbon dioxide collector (100) can be branched from the sixth pipe (L6) between the wet dust collector (50) and the power plant (1).

[0159] If the third gas is not cooled to the third temperature through the above wet dust collector (50), a plurality of heat exchangers can be installed in the sixth pipe (L6) between the melting furnace (20) and the high-temperature dust collector (90) to obtain high-temperature and medium-temperature steam.

[0160] The above high-temperature steam can be used in equipment used in the steelmaking process as described above, and the medium-temperature steam can be delivered to the regenerator (120) of the carbon dioxide capturer (100) and utilized to separate carbon dioxide from the ammonia solution in which the carbon dioxide is dissolved.

[0161] Alternatively, the third gas can be transferred through the fifth pipe (L5) to the first heat exchanger (30) or second heat exchanger (35) located in the first pipe (L1) or second pipe (L2), or transferred to the wet dust collector (50) to convert the third gas to a third temperature.

[0162]

[0163] [5th ​​Example]

[0164] FIG. 6 illustrates a configuration diagram of the fifth embodiment of the present invention.

[0165] Since this embodiment adopts the configuration of the fourth embodiment above, a description of common details is omitted.

[0166] The third gas generated during the operation of the above melting furnace (20) can be transferred to the above power plant (1) through the sixth pipe (L6).

[0167] A third heat exchanger (37) may be interposed between the high-temperature dust collector (90) and the wet dust collector (50) in the above-mentioned sixth pipe (L6).

[0168] The third heat exchanger (37) can obtain medium-temperature steam from the third gas flowing into the sixth pipe (L6) and supply it to the regenerator (120) of the carbon dioxide collector (100) through the seventh pipe (L7).

[0169] In addition, it is obvious that throughout all embodiments of the present invention described above, the carbon dioxide captured in the carbon dioxide capturer (100) can be directly supplied to the carbon dioxide storage (200) through a separate pipe.

[0170]

[0171] Although the present invention has been described above with reference to the illustrated drawings, the present invention is not limited by the embodiments and drawings disclosed in this specification, and it is obvious that various modifications can be made by a person skilled in the art within the scope of the technical concept of the present invention. Furthermore, even if the effects of the configuration of the present invention were not explicitly described while describing the embodiments of the present invention above, it is natural to acknowledge that the effects predictable by said configuration should also be recognized.

Claims

1. In a steelmaking process using a fluidized bed furnace (10) and a melting furnace (20), A first pipe (L1) that delivers the first gas generated during the operation of the above flow path (10) to the power plant (1); A first heat exchanger (30), a dry dust collector (40), a second heat exchanger (35), a wet dust collector (50), and a TRP (60) sequentially interposed in the first pipe (L1); A second pipe (L2) branched from the first pipe (L1) between the wet dust collector (50) and the TRP (60) and connected to the flow path (10); A carbon dioxide collector (100) that captures carbon dioxide and is interposed in the second pipe (L2); A third pipe (L3) that transfers medium-temperature steam produced in the second heat exchanger (35) to the carbon dioxide capture device (100); A fourth pipe (L4) that transfers the carbon dioxide captured in the carbon dioxide capturer (100) to a carbon dioxide storage tank (200); A carbon dioxide capture system for a steelmaking process comprising: a first compressor (70) interposed in the second pipe (L2) downstream of the carbon dioxide capture device (100) to compress the second gas from which carbon dioxide has been removed from the first gas and supply it to the fluidized bed (10).

2. In Claim 1, The above carbon dioxide capture system for a steelmaking process is characterized by comprising an absorber (110) that absorbs carbon dioxide from the first gas into an ammonia solution and a regenerator (120) that is connected to the third pipe (L3) and separates carbon dioxide from the ammonia solution containing carbon dioxide using medium-temperature steam.

3. In Claim 1, A carbon dioxide capture system for a steelmaking process, characterized in that the second heat exchanger (35) and the wet dust collector (50) are interposed in the second pipe (L2) located upstream of the carbon dioxide capture device (100).

4. In Claim 1, A carbon dioxide capture system for a steelmaking process characterized in that the above wet dust collector (50) is interposed in a second pipe (L2) located upstream of the carbon dioxide capture device (100).

5. In Claim 1, A carbon dioxide capture system for a steelmaking process, characterized in that a fifth pipe (L5) is installed to transfer a third high-temperature gas generated during the operation of the melting furnace (20) to the carbon dioxide capture device (100), and a high-temperature dust collector (90) and a wet dust collector (50) are sequentially interposed in the fifth pipe (L5).

6. In Claim 2, A carbon dioxide capture system for a steelmaking process characterized by having a second compressor (130) interposed in the fourth pipe (L4) above.

7. In Claim 1, A carbon dioxide capture system for a steelmaking process characterized in that the above-mentioned fourth pipe (L4) is connected to a carbon dioxide storage tank.

8. In Claim 2, In one embodiment of the present invention, the carbon dioxide capture system for a steelmaking process is characterized in that the carbon dioxide capturer (100) separates carbon dioxide from the first gas using at least one of an amine or an inorganic salt.

9. In a steelmaking process using a fluidized bed furnace (10) and a melting furnace (20), A first step in which a high-temperature first gas generated during the operation of the above-mentioned flow path (10) is passed through a second heat exchanger (35) to obtain medium-temperature steam and cooled to a second temperature; A second step of filtering impurities contained in the first gas that has undergone the first step using a wet dust collector (50) and raising it to a third temperature; A third step of guiding a portion of the first gas that has passed through the second step to a carbon dioxide capture device (100); A fourth step of supplying the medium-temperature steam produced in the first step above to the carbon dioxide capture device (100); A fifth step of capturing carbon dioxide contained in the first gas with an ammonia solution in the carbon dioxide capturer (100) and separating the carbon dioxide with medium-temperature steam; A method for capturing carbon dioxide in a steelmaking process comprising a sixth step of supplying the second gas, from which carbon dioxide has been removed from the first gas in the fifth step above, to the fluidized bed (10).

10. In Claim 9, A method for capturing carbon dioxide in a steelmaking process, characterized by including a step in which the first gas that was not supplied to the carbon dioxide capturer (100) in the third step is supplied to the TRP (60) to produce electricity.

11. In Claim 9, A method for capturing carbon dioxide in a steelmaking process, characterized in that the carbon dioxide captured in the above 5th step is supplied to a carbon dioxide storage tank.

12. In Claim 9, A method for capturing carbon dioxide in a steelmaking process, characterized in that in the first step, the first gas passes through a first heat exchanger (30) to obtain high-temperature steam and is cooled to a first temperature, and the first gas passes through a dry dust collector (40) and then passes through a second heat exchanger (35).

13. In Claim 9, A method for capturing carbon dioxide in a steelmaking process, characterized by including the step of guiding a third high-temperature gas generated during the operation of the melting furnace (20) to the carbon dioxide capture device (100).

14. In Claim 13, A method for capturing carbon dioxide in a steelmaking process, characterized in that the third gas passes through a high-temperature dust collector (90) to filter out impurities first, and then passes through a wet dust collector (50) to filter out impurities second and simultaneously undergoes a step of raising it to a third temperature, thereby being guided to the carbon dioxide capture device (100).

15. In Claim 9, A method for capturing carbon dioxide in a steelmaking process, characterized in that the carbon dioxide capturer (100) captures carbon dioxide through the steps of adsorbing carbon dioxide from the first gas onto an ammonia solution and exposing the medium-temperature steam to the ammonia solution to extract carbon dioxide.

16. In either Claim 9 or Claim 15, A method for capturing carbon dioxide in a steelmaking process characterized by using either an amine or an inorganic salt instead of the above ammonia solution.

17. In Claim 10, A method for capturing carbon dioxide in a steelmaking process, characterized in that the first gas supplied to the TRP (60) is supplied through a wet dust collector (50).

18. In a steelmaking process using a fluidized bed furnace (10) and a melting furnace (20), A first step of passing a first high-temperature gas generated during the operation of the above fluid flow path (10) through a first heat exchanger (30) to obtain high-temperature steam and raise it to a first temperature; A second step of filtering impurities contained in the first gas that has undergone the first step using a dry dust collector (40); A third step of passing a portion of the first gas at the first temperature that has passed through the second step above through a second heat exchanger (35) to obtain medium-temperature steam and make it at the second temperature; A fourth step of filtering impurities contained in the first gas at the second temperature that has undergone the third step above using a wet dust collector (50) to make it at the third temperature; A fifth step of guiding the first gas that has passed through the above fourth step to a carbon dioxide capture device (100); Step 6, supplying the medium-temperature steam produced in Step 3 above to the carbon dioxide capture device (100); Step 7, capturing carbon dioxide contained in the first gas with an ammonia solution in the carbon dioxide capturer (100) and separating the carbon dioxide with medium-temperature steam; A method for capturing carbon dioxide in a steelmaking process comprising the eighth step of supplying the second gas, from which carbon dioxide has been removed from the first gas in the seventh step above, to the fluidized bed (10).

19. In Claim 18, A method for capturing carbon dioxide in a steelmaking process, characterized by including a step of supplying the first gas that was not supplied to the carbon dioxide capturer (100) in the third step to the TRP (60) to produce electricity.

20. In Claim 18, A method for capturing carbon dioxide in a steelmaking process, characterized by including a step of guiding a third gas generated during the operation of the melting furnace (20) to the carbon dioxide capture device (100).

21. In claim 20, A method for capturing carbon dioxide in a steelmaking process, characterized by passing the third gas through a high-temperature dust collector (90) to filter out impurities contained in the third gas before it is guided to the carbon dioxide capturer (100), and passing it through a wet dust collector (50) to filter out impurities remaining in the third gas and raise it to a third temperature.

22. In a steelmaking process using a fluidized bed furnace (10) and a melting furnace (20), A first step of passing a first high-temperature gas generated during the operation of the above fluid flow path (10) through a first heat exchanger (30) to obtain high-temperature steam and raise it to a first temperature; A second step of filtering impurities contained in the first gas that has undergone the first step using a dry dust collector (40); A third step in which the first gas that has passed through the second step above passes through a second heat exchanger (35) to obtain medium-temperature steam and raise it to a second temperature; A fourth step of guiding a portion of the first gas that has passed through the third step above to a carbon dioxide capture device (100); A fifth step of supplying the medium-temperature steam produced in the third step above to the carbon dioxide capture device (100); Step 6, capturing carbon dioxide contained in the first gas with an ammonia solution in the carbon dioxide capturer (100) and separating the carbon dioxide with medium-temperature steam; A method for capturing carbon dioxide in a steelmaking process comprising a seventh step of supplying the second gas, from which carbon dioxide has been removed from the first gas in the sixth step above, to the fluidized bed (10).

23. In Claim 22, A method for capturing carbon dioxide in a steelmaking process, characterized by including a step of supplying the first gas that was not supplied to the carbon dioxide capturer (100) in the above fourth step to the TRP (60) to produce electricity.

24. In Claim 22, A method for capturing carbon dioxide in a steelmaking process, characterized by including the step of guiding a third high-temperature gas generated during the operation of the melting furnace (20) to the carbon dioxide capture device (100).

25. In Claim 24, A method for capturing carbon dioxide in a steelmaking process, characterized in that the third gas passes through a high-temperature dust collector (90) to filter out impurities first, and then passes through a wet dust collector (50) to filter out impurities second and simultaneously undergoes a step of raising it to a third temperature, thereby being guided to the carbon dioxide capture device (100).

26. In any one of claims 9 to 25, A method for capturing carbon dioxide in a steelmaking process, characterized in that the first temperature is higher than the second temperature and the second temperature is higher than the third temperature.

Images