System for controlling realtime carbonation rate of recycled wash water, and operation method for the same

Abstract

A real-time carbonation control system for recycled concrete water and a method of operation are provided, which allow for the setting of an optimal CO2 injection flow rate, prevention of excessive heat generation and inefficient reactions, quantitative determination of the point of complete carbonation of the recycled concrete water, prevention of wear caused by solids in the recycled concrete water and stable operation over a long period, and management of solids by monitoring the solid content ratio that changes over time, thereby enabling easy management of ready-mix concrete quality even when using recycled water. This is achieved by evaluating the reaction characteristics of the recycled concrete water, in which carbonation reaction proceeds by injecting carbon dioxide (CO2), through an integrated analysis of multiple physical properties such as density, temperature, and pH in real time.

Description

Technology Field

[0001] The present invention relates to a system for controlling the carbonation degree of recovered water, and more specifically, to a system for controlling the real-time carbonation degree (or carbonation rate) of recovered water and a method for operating the same, which enables the real-time carbonation degree (or carbonation rate) of recovered water to be controlled by controlling the injection flow rate and the density of the recovered water within a recovered water storage tank (reactor) for the recycling of recovered water in concrete. Background Technology

[0002] In line with global greenhouse gas reduction targets, domestic industries are also implementing carbon neutrality policies to meet these goals. The construction industry is also currently developing carbon neutrality R&D technologies to respond to this situation.

[0003] Since the construction industry accounts for about 10% of total global greenhouse gas emissions, it is necessary to secure greenhouse gas reduction technologies, and various technologies are being developed to reduce carbon dioxide (CO2) using concrete, which is the most widely used construction material.

[0004] Recently, Carbon Capture, Utilization and Storage (CCUS) technology has been regarded as an important means of reducing greenhouse gases, particularly in the United States and Europe, as a post-emission reduction method that stores already emitted carbon dioxide or reuses it as a resource; consequently, technologies utilizing concrete for such CO2 utilization (CCU) are emerging.

[0005] Meanwhile, as prior art related to carbonation, Korean registered patent No. 10-1863671 discloses an invention titled "Carbonation curing equipment, method for manufacturing carbonated concrete and method for carbon dioxide fixation," which will be explained with reference to FIG. 1.

[0006] Figure 1 is a diagram showing the configuration of a carbonation curing facility according to conventional technology.

[0007] Referring to FIG. 1, a carbonation curing facility (20) according to the prior art comprises: a carbonation curing tank (21) having an interior that is a shielded space; an exhaust gas circulation device (22) for supplying and circulating exhaust gas discharged from a thermal power plant (11) into the carbonation curing tank (21); and a temperature and humidity control device (23) for adjusting the temperature and humidity of the exhaust gas inside the carbonation curing tank (21).

[0008] Here, the concrete (or cementitious body) to be carbonated and cured is contained in the carbonation curing tank (21) such that the surface requiring carbonation is exposed to the gas atmosphere within the shielded space or is in a demolded state.

[0009] Additionally, an exhaust gas supply pipe is branched in the middle of a flue (13) connecting the exhaust gas outlet of a thermal power plant (11) and a chimney (12), and at this time, exhaust gas discharged from the thermal power plant (11) is constantly supplied into a carbonation curing tank (21) through an exhaust gas circulation device (22) via an exhaust gas blower (14) installed in the exhaust gas supply pipe during the carbonation curing period.

[0010] In addition, by providing a water contact device (24), that is, a device for contacting exhaust gas with water or steam, between the exhaust gas supply pipe's air blower (14) and the exhaust gas circulation device (22), the exhaust gas discharged from the thermal power plant (11) can be contacted with water or steam before being supplied into the carbonation curing tank (21), thereby improving carbonation efficiency.

[0011] According to a carbonation curing facility based on conventional technology, by using a thermal power plant as a carbon dioxide supply source, high-concentration carbon dioxide can be supplied into the carbonation curing tank in a stable and large quantity.

[0012] In addition, by encapsulating carbon dioxide (greenhouse gas) contained in the exhaust gas emitted from a thermal power plant into concrete, the carbon dioxide is physically and chemically immobilized within the concrete. Accordingly, it is possible to significantly reduce the emission of carbon dioxide from the thermal power plant and simultaneously provide a new method for carbon dioxide immobilization.

[0013] Meanwhile, as prior art related to carbon dioxide curing, Korean published patent number 2022-94688 discloses an invention titled "Carbon dioxide curing apparatus and curing method for mortar and concrete," which will be explained with reference to FIG. 2.

[0014] FIG. 2 is a perspective view illustrating a carbon dioxide curing device for mortar and concrete according to conventional technology.

[0015] Referring to FIG. 2, a carbon dioxide curing device for mortar and concrete according to the prior art includes a chamber (41), an air compressor (42), a carbon dioxide supply device (43), an air pressure gauge (44), and a gas concentration gauge (45). Additionally, the chamber (41) is configured to include an air discharge section (41a), a gas injection section (41b), a measuring section, a partition plate, a door section, and a control section.

[0016] The chamber (41) is a space where the curing of the microbiome (30) takes place, and can maintain the interior in a sealed state or form a vacuum state, and can maintain the carbon dioxide concentration, temperature, and humidity inside at a constant level while the curing of the microbiome (30) takes place.

[0017] A receiving space is formed inside the chamber (41) so as to accommodate a plurality of microbiota (30). For example, the receiving space may be a polyhedral or cylindrical space.

[0018] A gas injection section (41b) is formed on one side of the chamber (41) and injects carbon dioxide into the chamber (41).

[0019] The air discharge section (41a) is configured to draw in air from the chamber (41) to increase the carbon dioxide concentration within the chamber (41) and to discharge the air from the chamber (41), and is formed on one side of the chamber (41) so as to be spaced apart from the gas injection section (41b).

[0020] The air pressure measuring device (44) is connected to the upper part of the chamber (41) and measures the air pressure inside the chamber (41).

[0021] A gas concentration meter (45) is connected to the upper part of the chamber (41) and measures the carbon dioxide concentration inside the chamber (41).

[0022] The control unit controls the gas injection unit (41b) and the air exhaust unit (41a) so that the carbon dioxide concentration inside the chamber (41) becomes 99.9%.

[0023] In other words, a carbon dioxide curing device for mortar and concrete according to conventional technology controls an air discharge unit so that the air pressure inside the chamber becomes lower than atmospheric pressure by discharging air inside the chamber, and is configured to control a gas injection unit so that carbon dioxide is supplied into the chamber when the air pressure inside the chamber is lowered to a preset pressure.

[0024] According to a carbon dioxide curing device for mortar and concrete based on conventional technology, it is possible to provide an environment with a carbon dioxide concentration of 99.9% or higher for curing cementitious secondary products such as mortar and concrete.

[0025] In addition, by controlling air discharge and carbon dioxide injection based on chamber air pressure and carbon dioxide concentration data through the control unit, the carbon dioxide concentration inside the chamber can be easily set and maintained at 99.9%.

[0026] Meanwhile, Figure 3 is a diagram showing the components of the recovered water.

[0027] As shown in Fig. 3, the recovered water consists of supernatant, sludge water, and sludge solids. At this time, the supernatant and sludge water of the recovered water are recycled as mixing water for concrete, and the sludge solids that are not treated as mixing water are disposed of as construction waste through dewatering and natural drying processes. In addition, when the recovered water is used as mixing water for concrete, the amount of solids is limited.

[0028] Meanwhile, as prior art related to a method for fixing carbon dioxide (CO2) using recycled ready-mix concrete water, Korean registered patent No. 10-2632870 discloses an invention titled "Method for fixing CO2 using recycled ready-mix concrete water using a rapid carbonation reaction by supercritical CO2," which will be explained with reference to FIG. 4.

[0029] Figure 4 is a schematic diagram of a supercritical carbon dioxide reactor according to conventional technology.

[0030] Referring to FIG. 4, a supercritical carbon dioxide reactor according to the prior art is configured to supply supercritical carbon dioxide (CO2) to a reactor (61) through a gas booster (64).

[0031] A heating plate (51) for temperature control and a stirrer (62) for mixing ready-mix concrete recovery water and supercritical carbon dioxide (CO2) are installed in the reactor (61). The stirrer (62) is configured such that a plurality of stirring blades (62a) are spaced apart and connected to a longitudinal shaft installed in the center of the reactor (61), and the shaft is rotated by a motor.

[0032] The interior of the reactor (61) is configured so that the temperature and pressure are measured through a thermocouple (52) and a pressure gauge (53). At this time, the reactor (61) can be constructed as a pressure vessel and configured to be sealed by the connection of a cover (55), and the water generated together with calcium carbonate (CaCO3) by the rapid carbonation reaction of calcium hydroxide (Ca(OH)2) in the ready-mix concrete recovery water is discharged through the drain (54), and the unreacted carbon dioxide (CO2) can be collected again after being exhausted.

[0033] The gas booster (64) is a device for pressurizing carbon dioxide (CO2) gas stored in a carbon dioxide cylinder (63) to a high pressure and injecting it into a reactor (61) in a supercritical state, and an air compressor (65) is additionally connected to the gas booster (64) to stably maintain the supercritical state of carbon dioxide (CO2).

[0034] In addition, the method of fixing carbon dioxide (CO2) in ready-mix concrete recovery water according to the conventional technology using a supercritical carbon dioxide reactor illustrated in Fig. 4 is a method of injecting captured carbon dioxide (CO2) into ready-mix concrete recovery water in a supercritical state so that calcium carbonate (CaCO3) is produced by the rapid carbonation reaction of calcium hydroxide (Ca(OH)2) in ready-mix concrete recovery water by supercritical carbon dioxide (CO2).

[0035] At this time, the recycled ready-mix concrete has a solid content of 5 to 25 wt%, and the solid content contains 30 wt% or more of calcium oxide (CaO) when analyzed by XRF.

[0036] In addition, supercritical carbon dioxide (CO2) is injected into a sealed reactor containing recycled concrete water, and while the temperature inside the reactor is maintained at 35–80°C and the pressure at 75–160 bar, the recycled concrete water and supercritical carbon dioxide (CO2) are stirred by driving a stirrer rotating at 100–400 rpm in the center of the reactor for 5–30 minutes, and complete carbonation of the solids in the recycled concrete water is achieved through a rapid carbonation reaction.

[0037] According to a supercritical carbon dioxide reactor based on conventional technology, by utilizing recycled ready-mix concrete waste, which is a highly alkaline construction waste, as a fixative source for large amounts of carbon dioxide (CO2) discharged and captured from various industrial facilities, it is possible to reduce carbon dioxide (CO2) emissions, alleviate the burden of treating recycled ready-mix concrete waste, and generate calcium carbonate (CaCO3), which has various industrial uses.

[0038] Meanwhile, as prior art related to a method for fixing carbon dioxide using recycled concrete water, Korean registered patent No. 10-2811970 discloses an invention titled "Method for fixing carbon dioxide using recycled concrete water, concrete admixture manufactured using the method, and pressurized carbonation reaction device for solids in recycled concrete water," which will be explained with reference to FIGS. 5a and 5b.

[0039] FIG. 5a is a schematic diagram of a pressurized carbonation reaction device for solids in concrete recovery water according to conventional technology, and FIG. 5b is an operation flowchart showing a carbon dioxide fixation method using concrete recovery water according to conventional technology.

[0040] As shown in FIG. 5a, a pressurized carbonation reaction device for solids in concrete recovery water according to the prior art comprises a reactor, a spray nozzle, a pressure gauge, a gas booster, a pressure reducing valve, an EGR (Exhaust Gas Recirculation), a stirrer, a heating device, a temperature sensor, and a solid-liquid separation device.

[0041] The reactor receives concrete recovery water and carbon dioxide (CO2) to cause a carbonation reaction between cement hydration products existing as solids in the concrete recovery water and unhydrated cement particles.

[0042] The spray nozzle supplies carbon dioxide (CO2) gas in the form of microbubbles to the concrete recovery water inside the reactor, and the pressure gauge measures the internal pressure of the reactor.

[0043] The control unit controls the supply of carbon dioxide (CO2) gas through the injection nozzle so that even after the carbon dioxide (CO2) in the concrete recovery water of the reactor becomes supersaturated, the internal pressure of the reactor reaches a set pressure in the range of 3 to 20 bar.

[0044] The gas booster converts carbon dioxide (CO2) gas stored in a liquid state in a carbon dioxide (CO2) cylinder into a gaseous state and supplies it to the injection nozzle. At this time, the injection pressure of the carbon dioxide (CO2) microbubbles is formed to be 3 bar or higher.

[0045] The pressure reducing valve serves to lower the internal pressure of the reactor by releasing carbon dioxide (CO2) gas after the carbonation reaction of the solid is completed.

[0046] The EGR supplies carbon dioxide (CO2) gas emitted through the pressure reducing valve to the carbon dioxide (CO2) cylinder.

[0047] A stirrer is installed in the reactor to stir the concrete recovery water, and the stirrer consists of a rotating rod that rotates on an axis by a magnet drive motor and a pitched blade coupled to the rotating rod.

[0048] The heating device heats the reactor, and the temperature sensor measures the internal temperature of the reactor.

[0049] The solid-liquid separation device separates the concrete recovery water discharged from the reactor into supernatant and carbonate after the complete carbonation of the solids.

[0050] Specifically, referring to FIGS. 5a and 5b, a carbon dioxide fixation method using concrete recovery water according to the prior art is characterized by supplying captured carbon dioxide (CO2) gas in a microbubble state into concrete recovery water contained in a reactor (S11~S14), and continuing to supply carbon dioxide (CO2) gas until the internal pressure of the reactor reaches a set pressure even after the carbon dioxide (CO2) in the concrete recovery water of the reactor is supersaturated (S15~S17), thereby causing carbonation of cement hydration products and unhydrated cement particles existing as solids in the concrete recovery water, so as to produce carbonates containing calcium carbonate (CaCO3) components (S18~S20).

[0051] Specifically, a carbon dioxide fixation method using concrete recovery water according to conventional technology can be explained by dividing it into the following steps: supplying concrete recovery water to a reactor → injecting carbon dioxide (CO2) gas into the concrete recovery water as microbubbles → increasing the internal pressure of the reactor by continuously supplying carbon dioxide (CO2) gas and completely carbonating the solids in the concrete recovery water.

[0052] At this time, before supplying the concrete recovery water to the reactor, pretreatment processes such as aggregate removal and solid content adjustment may be performed, and before supplying the concrete recovery water to the reactor and injecting carbon dioxide (CO2) gas in the form of microbubbles, the temperature of the concrete recovery water can be adjusted to a range of 10 to 40°C by heating the inside of the reactor.

[0053] In addition, during the step of completely carbonating the solids in the concrete recovery water, the process of stirring the concrete recovery water can be performed in parallel, and after the carbonation reaction is completed, the internal pressure of the reactor can be reduced and the carbon dioxide (CO2) dissociation gas can be discharged and circulated to a carbon dioxide (CO2) gas cylinder for recycling.

[0054] In addition, concrete recovery water can be discharged from the reactor and the supernatant and carbonates can be separated using a solid-liquid separation device. Subsequently, the supernatant can be reused as mixing water for concrete, and the carbonates can be reused as concrete admixtures or various industrial raw materials.

[0055] According to a carbon dioxide fixation method using recycled concrete water based on conventional technology, carbon dioxide (CO2) can be directly fixed by completely carbonating the solid components of recycled concrete water, which contains a large amount of calcium oxide (CaO), under commercial pressurized conditions (3 to 20 bar), thereby directly contributing to the reduction of carbon dioxide (CO2) emissions while ensuring economic efficiency and safety.

[0056] In addition, carbon dioxide (CO2) gas generated from various industrial facilities, including cement production facilities, can be captured and utilized as a source of CO2 to carbonate the solids in the concrete recovery water.

[0057] In addition, after complete carbonation of the solids in the concrete recovery water, solid-liquid separation (i.e., separation of supernatant and carbonate) can be performed, allowing the supernatant to be used as concrete mixing water and the carbonate to be used as a concrete admixture.

[0058] Meanwhile, U.S. Patent No. 11,958,212 discloses an invention titled "Method and composition for treating concrete wash water with carbon dioxide," which discloses a method and composition for treating wash water generated during the concrete production process with carbon dioxide (CO2) and reusing it as mixing water for a new concrete batch.

[0059] According to a method for treating concrete wash water with carbon dioxide based on conventional technology, recycled water can be used for the production of new concrete by recycling recycled water, which is equipment wash water generated in ready-mix concrete plants, and reacting it with carbon dioxide (CO2). In addition,

[0060] In addition, the injected carbon dioxide (CO2) reacts with cement particles in the recovered water to convert them into carbonate minerals, and in this process, the recovered water can be stabilized, thereby increasing its reusability.

[0061] Accordingly, production costs can be reduced by decreasing the use of new cement and fresh water, and in addition, by injecting carbon dioxide (CO2) during ready-mix concrete production, not only can the amount of stored carbon dioxide (CO2) be increased, but the strength of the concrete can also be improved.

[0062] However, in the case of a method for treating concrete wash water with carbon dioxide according to conventional technology, a separate reactor is not provided, and the aspect of controlling the solid content in the recovered water is not disclosed.

[0063] Meanwhile, the field of concrete utilizing carbon dioxide (CO2) presents examples of use such as the use of mineral carbonate materials (e.g., calcium carbonate (CaCO3), magnesium carbonate (MgCO3), etc.) obtained through the conversion of carbon dioxide (CO2) captured in CCUS technology as aggregates and fillers, the application of carbon dioxide (CO2) curing to secondary concrete products, and the injection of carbon dioxide (CO2) during the concrete production process.

[0064] In addition, there is a recovered water mineral carbonation technology as one of the technologies for injecting carbon dioxide (CO2) during the concrete production process.

[0065] Concrete recovery water generated during the washing and recovery process of concrete remaining in ready-mix trucks contains cementitious products (CSH, Ca(OH)2, Ettringite, etc.), unreacted cement particles, and sand. Recently, a technology that recycles mineralized recovery water into concrete mixing water by injecting CO2, utilizing the high reactivity between calcium ions present in the water and carbon dioxide (CO2), has been gaining attention.

[0066] However, since the carbonation reaction of such recovered water varies non-linearly due to various factors such as the reaction rate with carbon dioxide (CO2), temperature, solid content, and the flow rate of injected carbon dioxide (CO2), there is a limitation in that it is difficult to precisely track the progress of the reaction using existing pH-based carbonation evaluation methods.

[0067] The most accurate existing method for evaluating carbonation is thermogravimetric analysis, but it has the disadvantage of being cumbersome and taking a long time to analyze because it requires completely removing moisture from the concrete recovery water and then analyzing the remaining solids.

[0068] Therefore, in order to apply mineral carbonation technology for recovered water to on-site facilities, a system and method capable of evaluating the carbonation rate of recovered concrete water in real time are required.

[0069] In addition, conventional pH measurements have a limitation in that while they can distinguish between the beginning and end of carbonation (initial and final stages) because a rapid acidification (pH drop) occurs when carbonation is nearly complete, it is difficult to track the intermediate reaction process in real time.

[0070] Ultimately, for recovered water mineral carbonation technology to be used in industrial settings, there is a need for a method to evaluate the degree of carbonation—the progress rate of the carbon dioxide (CO2) reaction—in real-time and quantitatively. Prior art literature

[0071] Korean Registered Patent No. 10-2811970 (Registration Date: May 20, 2025), Title of Invention: "Method for fixing carbon dioxide using recycled concrete water, concrete admixture manufactured using the method, and pressurized carbonation reaction device for solids in recycled concrete water" Korean Registered Patent No. 10-2755968 (Registration Date: January 13, 2025), Title of Invention: "Equipment for manufacturing a concrete forming composition" Korean Registered Patent No. 10-2668326 (Registration Date: May 17, 2024), Title of Invention: "Concrete recycled water recycling system" Korean Registered Patent No. 10-2632870 (Registration Date: January 30, 2024), Title of Invention: "Method for fixing CO2 using recycled ready-mix concrete water using a rapid carbonation reaction by supercritical CO2" Korean Published Patent No. Korean Patent No. 2022-0094688 (Publication Date: July 6, 2022), Title of Invention: "CO2 Curing Apparatus and Curing Method for Mortar and Concrete" Korean Patent No. 2013-0137190 (Publication Date: December 16, 2013), Title of Invention: "Carbonation Curing Equipment, Method for Manufacturing Carbonated Concrete, and Method for Immobilizing Carbon Dioxide" U.S. Patent No. 11,958,212 (Registration Date: April 16, 2024), Title of Invention: "Method and Composition for Treating Concrete Wash Water with Carbon Dioxide" The problem to be solved

[0072] The technical objective of the present invention, which aims to solve the aforementioned problems, is to provide a real-time carbonation degree control system for concrete recovery water and a method of operating the same, which can set an optimal carbon dioxide (CO2) injection flow rate by integrally analyzing multiple physical properties, such as density, temperature, and pH, and evaluating the reaction characteristics of concrete recovery water in which a carbonation reaction proceeds by injecting carbon dioxide (CO2) in real time.

[0073] Another technical objective of the present invention is to provide a real-time carbonation degree control system for recycled concrete water and a method for operating the same, which can prevent excessive heat generation and inefficient reactions and quantitatively determine the point of complete carbonation of the recycled concrete water.

[0074] Another technical objective of the present invention is to provide a real-time carbonation degree control system for concrete recovery water and a method of operating the same, which prevents wear caused by solids in the concrete recovery water and enables stable operation for a long period of time. means of solving the problem

[0075] As a means to achieve the aforementioned technical challenge, the real-time carbonation degree control system for concrete recovery water according to the present invention comprises: a recovery water storage tank into which carbon dioxide (CO2) is injected to recycle the concrete recovery water, wherein the recovery water is a reactor for storing and processing the concrete recovery water; a temperature sensor installed within the recovery water storage tank to measure the temperature of the concrete recovery water in real time; an impeller pump that supplies the concrete recovery water stored within the recovery water storage tank to an inline densimeter and an inline pH meter through piping; an inline pH meter that measures the pH of the concrete recovery water transferred through the impeller pump in real time; an inline densimeter that measures the density of the concrete recovery water transferred through the impeller pump in real time; and a control panel that is a data collection and analysis module embedded with a carbonation degree calculation algorithm, which evaluates the reaction characteristics of the concrete recovery water in which the carbonation reaction proceeds by injecting carbon dioxide (CO2) by integrating multiple physical property values ​​of density, pH, and temperature in real time, and sets the optimal carbon dioxide (CO2) injection flow rate.and includes a carbon dioxide injection flow rate control device (170) that injects carbon dioxide (CO2) supplied to the recovery water storage tank under the control of the control panel, wherein the control panel primarily determines that the maximum carbonation level has been reached when the density value measured by the inline densimeter reaches the maximum density value, and additionally determines that the maximum carbonation level has been reached when it is confirmed that no further rise in temperature occurs and the measured pH drops below the field correction threshold (pH), and calculates the carbonation level based on the density value, and the control panel monitors the rate of change of the density value measured by the inline densimeter in real time and compares the carbonation level predicted by the reference model with the real-time carbonation level, and if it is determined that the expected time to reach the target carbonation level is delayed, increases the carbon dioxide (CO2) injection flow rate, and if it is determined that the expected time to reach the target carbonation level is advanced, decreases the carbon dioxide (CO2) injection flow rate, and if the internal temperature of the recovery water storage tank measured by the temperature sensor rises above the limit temperature, carbon dioxide (CO2) The injection flow rate is reduced or temporarily blocked, and the limiting temperature is set to a range of 35 to 40℃.

[0076] Meanwhile, as another means for achieving the aforementioned technical problem, the method of operating a real-time carbonation degree control system for concrete recovered water according to the present invention comprises: a) a step of measuring the solid content and volume of concrete recovered water in a recovery water storage tank before injecting carbon dioxide (CO2); b) a step in which a control panel sets a target reaction time for reaching a target carbonation degree of concrete recovered water in the recovery water storage tank; c) a step in which the control panel determines the carbon dioxide (CO2) injection flow rate to be injected into the recovery water storage tank; d) a step in which the control panel predicts the carbonation degree and temperature of the concrete recovered water based on a reference model, which is reference experimental data; e) a step in which the control panel initiates a concrete recovered water treatment operation according to the set conditions of the target reaction time, carbon dioxide (CO2) injection flow rate, and limiting temperature; f) a step of measuring density, pH, and temperature in real time in response to the concrete recovered water treatment operation; g) a step in which the control panel compares the predicted carbonation degree with the real-time carbonation degree. h) a step in which the control panel controls the carbon dioxide (CO2) flow rate according to the carbonation degree and limiting temperature; and i) a step in which the control panel determines that the carbonation of the concrete recovery water is complete when the target carbonation degree is reached. Effects of the invention

[0077] According to the present invention, the reaction characteristics of concrete recovery water in which carbonation reaction proceeds by injecting carbon dioxide (CO2) are evaluated in real time by integrally analyzing multiple physical properties such as density, temperature, and pH, thereby allowing the optimal carbon dioxide (CO2) injection flow rate to be set.

[0078] According to the present invention, excessive heat generation and inefficient reactions can be prevented, and the point at which concrete recovery water is completely carbonated can be quantitatively determined.

[0079] According to the present invention, wear caused by solids in the concrete recovery water is prevented, and stable operation for a long time is possible.

[0080] According to the present invention, since solid content can be managed by monitoring the solid content ratio that changes over time, the quality of ready-mix concrete can be easily managed even when using recycled water. Brief explanation of the drawing

[0081] Figure 1 is a diagram showing the configuration of a carbonation curing facility according to conventional technology. FIG. 2 is a perspective view illustrating a carbon dioxide curing device for mortar and concrete according to conventional technology. Figure 3 is a diagram showing the components of the recovered water. Figure 4 is a schematic diagram of a supercritical carbon dioxide reactor according to conventional technology. FIG. 5a is a schematic diagram of a pressurized carbonation reaction device for solids in concrete recovery water according to conventional technology, and FIG. 5b is an operation flowchart showing a carbon dioxide fixation method using concrete recovery water according to conventional technology. FIG. 6 is a configuration diagram of a real-time carbonation degree control system for concrete recovery water according to an embodiment of the present invention. FIG. 7 is a detailed configuration diagram of a control panel in a real-time carbonation degree control system for concrete recovery water according to an embodiment of the present invention. FIG. 8a is a drawing showing a general shape of an impeller pump, and FIG. 8b is a drawing showing an impeller pump applied to a real-time carbonation degree control system for concrete recovery water according to an embodiment of the present invention. FIG. 9 is a flowchart illustrating the operation method of a real-time carbonation degree control system for concrete recovery water according to an embodiment of the present invention. FIG. 10 is a diagram illustrating a carbonation reference model according to the carbon dioxide injection flow rate of a recovered water with a solid content of 6% in a method of operating a real-time carbonation control system for recovered concrete water according to an embodiment of the present invention. FIG. 11 is a diagram illustrating the control of carbon dioxide injection flow rate when a difference occurs from the expected carbonation completion time in the operation method of a real-time carbonation degree control system for concrete recovery water according to an embodiment of the present invention. FIG. 12 is a diagram illustrating the control of carbon dioxide injection flow rate when the recovered water approaches the limiting temperature in the operation method of a real-time carbonation degree control system for recovered concrete water according to an embodiment of the present invention. Specific details for implementing the invention

[0082] Embodiments of the present invention are described below with reference to the attached drawings so that those skilled in the art can easily implement the invention. However, the present invention may be embodied in various different forms and is not limited to the embodiments described herein. Furthermore, in order to clearly explain the present invention in the drawings, parts unrelated to the explanation have been omitted, and similar parts throughout the specification are denoted by similar reference numerals.

[0083] Throughout the specification, when a part is described as "comprising" a certain component, this means that, unless specifically stated otherwise, it does not exclude other components but may include additional components. Furthermore, terms such as "…part" as used in the specification refer to a unit that processes at least one function or operation, and this may be implemented in hardware, software, or a combination of hardware and software.

[0084] [Real-time carbonation control system for concrete recovery water (100)]

[0085] FIG. 6 is a configuration diagram of a real-time carbonation degree control system for concrete recovery water according to an embodiment of the present invention.

[0086] Referring to FIG. 6, a real-time carbonation degree control system (100) for concrete recovery water according to an embodiment of the present invention comprises a recovery water storage tank (110), a temperature sensor (120), an impeller pump (130), an inline pH meter (140), an inline densimeter (150), a control panel (160), and a carbon dioxide injection flow rate control device (170).

[0087] The recovery water storage tank (110) is a reactor that stores and processes concrete recovery water, and carbon dioxide (CO2) is injected to recycle the concrete recovery water. The recovery water storage tank (110) has a recovery water inlet through which concrete recovery water flows in and a treated water outlet through which treated water collected from the recovery water storage tank (110) is discharged.

[0088] Additionally, the above-mentioned recovery water storage tank (110) has a first pipe formed to introduce concrete recovery water into the impeller pump (130), and a second pipe formed to return concrete recovery water flowing out from the inline density meter (150).

[0089] A temperature sensor (120) is installed in the recovery water storage tank (110) to measure the temperature of the concrete recovery water in real time. At this time, it is preferable that the temperature sensor (120) is a temperature sensor that includes a data logging function.

[0090] The impeller pump (130) supplies the concrete recovery water stored in the recovery water storage tank (110) through the piping to the inline density meter (150) and the inline pH meter (140).

[0091] The inline pH meter (140) measures the pH of the concrete recovery water transferred through the impeller pump (130) in real time.

[0092] The inline density meter (150) measures the density of the concrete recovery water transferred through the impeller pump (130) in real time. At this time, the other end of the inline density meter (150) is connected to the recovery water storage tank (110) so that the concrete recovery water can be returned.

[0093] The control panel (160) is a data collection and analysis module with a carbonation degree calculation algorithm embedded therein, and evaluates in real time the reaction characteristics of concrete recovery water in which carbonation reaction proceeds by injecting carbon dioxide (CO2) by integrating multiple physical properties such as density, temperature, and pH, and sets the optimal carbon dioxide (CO2) injection flow rate.

[0094] The carbon dioxide (CO2) injection flow rate control device (Mass Flow Controller) (170) injects carbon dioxide (CO2) supplied to the recovery water storage tank (110) under the control of the control panel (160).

[0095] Specifically, in the case of the real-time carbonation degree control system (100) for concrete recovery water according to an embodiment of the present invention, in order to evaluate the carbonation degree based on real-time density measurement, the density of the recovery water undergoing the carbonation reaction is continuously measured to track the degree of carbonation progress in real time.

[0096] Here, the carbonation rate is the ratio of carbon dioxide (CO2) fixed within a sample (carbonation rate), a value primarily measured in concrete or industrial byproducts.

[0097] In the real-time carbonation degree control system for concrete recovery water according to an embodiment of the present invention, the carbonation degree is analyzed as a percentage of the amount of carbon dioxide (CO2), and the value and density value of the amount of carbon dioxide (CO2) released through thermogravimetric analysis (TG) are calculated quantitatively.

[0098] Here, the carbon dioxide (CO2) fixation rate is a value expressed as a percentage (%) of the mass ratio of fixed carbon dioxide (CO2) to the total dry weight of the sample, and is an indicator for quantitatively evaluating how much carbon dioxide (CO2) the sample has absorbed and fixed, and is given as [Equation 1] below.

[0099]

[0100] In addition, the degree of carbonation is a value indicating the proportion of carbon dioxide (CO2) fixation of the sample obtained in the current reaction tank that has reached the maximum carbon dioxide (CO2) fixation obtained by completely reacting with carbon dioxide (CO2) when the solid content in the recovered water is 100% cement according to laboratory standards. That is, as an indicator for relatively evaluating the degree of carbonation progress of the current reaction sample, it is given as [Equation 2] below.

[0101]

[0102] Here, the amount of carbon dioxide (CO2) fixed in the current sample is presented through real-time density.

[0103] In particular, in the case of concrete, this refers to the phenomenon where carbon dioxide (CO2) in the atmosphere reacts with calcium hydroxide (Ca(OH)2) to lose alkalinity, and is measured using methods such as Differential Thermal Gravimetric Analysis.

[0104] Since a higher degree of carbonation leads to higher carbon dioxide (CO2) fixation efficiency, it is utilized as an important indicator in carbon capture and storage (CCS) technology and is closely linked to structural effects such as concrete durability and rebar corrosion.

[0105] In other words, carbonation is the ratio of carbon dioxide (CO2) fixation within a sample, and it is a key figure for CO2 capture, storage, and concrete durability evaluation.

[0106] Meanwhile, since the concrete recovery water contains solids, it is difficult to supply a stable and constant flow rate to the inline density meter (150) with a general pump, and accordingly, it is difficult to obtain stable density meter data.

[0107] Accordingly, a sample of the recovered concrete water is transferred from the recovered water storage tank (110) to an inline density meter (150) through piping using an impeller pump (130). At this time, the impeller pump (130) is designed with a sealed structure in which the impeller does not come into contact with the casing, as shown in FIG. 8b described later. Accordingly, wear caused by solids in the recovered concrete water is prevented, and stable operation for a long time is possible. When the maximum carbonation value obtained through repeated experiments is reached, the reaction is determined to be terminated.

[0108] Specifically, as the carbonation of the concrete recovery water progresses, the injected carbon dioxide (CO2) gas reacts with calcium hydroxide (Ca(OH)2) to form calcium carbonate (CaCO3) within the concrete recovery water. At this time, since the injected carbon dioxide (CO2) is fixed in the concrete recovery water in the form of chemically stable calcium carbonate (CaCO3) through the carbonation reaction, the density of the recovery water increases.

[0109] Accordingly, by measuring the increase in density caused by carbon dioxide (CO2) fixation, the amount of carbon dioxide (CO2) fixed among the injected carbon dioxide (CO2) can be estimated.

[0110] In other words, the amount of carbon dioxide (CO2) fixed can be estimated using densimeter measurements obtained through the following [Equation 3] to [Equation 8]. First, the solid fraction ( ) is given as in the following [Equation 3].

[0111]

[0112] Here, represents the weight of the solids, represents the weight of water.

[0113] Also, slurry weight ( ) is given as in the following mathematical formula 4, and the slurry volume ( ) is given as in the following mathematical formula 5.

[0114]

[0115]

[0116] Here, represents the solid content density, represents water density.

[0117] Also, slurry density ( ) is given as in the following mathematical formula 6, and accordingly, the solid fraction ( ) can be obtained as shown in the following [Equation 7] and [Equation 8].

[0118]

[0119]

[0120]

[0121] In other words, the carbon dioxide (CO2) fixation rate of the conventional thermogravimetric analysis method can be compared with the evaluation method according to the embodiment of the present invention as shown in [Table 1], indicating that the evaluation method according to the embodiment of the present invention is effective.

[0122]

[0123] Meanwhile, in the case of the real-time carbonation degree control system (100) of concrete recovery water according to an embodiment of the present invention, the carbon dioxide (CO2) injection flow rate is optimized control is performed, and the carbon dioxide (CO2) injection flow rate is controlled according to the volume and solid content of the concrete recovery water.

[0124] For example, if the CO2 injection flow rate is insufficient, the reaction time increases excessively, and the amount of CO2 consumed to achieve the same degree of carbonation also increases unnecessarily. Furthermore, if CO2 is injected excessively and the pH drops below 6, the slurry may become acidified, leading to the redissolution of already formed carbonates. In this case, the CO2 may dissociate and be released into the air. Additionally, if the CO2 injection flow rate is excessive, the temperature rises due to the rapid reaction, making it difficult to use as mixing water.

[0125] Therefore, by optimizing the carbon dioxide (CO2) injection flow rate, the stability and efficiency of the carbonation reaction can be simultaneously secured.

[0126] In addition, in the case of the real-time carbonation degree control system (100) for concrete recovery water according to an embodiment of the present invention, the density change rate is monitored in real time, and if it is predicted that the time to reach the expected carbonation degree will be delayed, the carbon dioxide (CO2) injection flow rate is increased, and conversely, if it is predicted that the time to reach the expected carbonation degree will be brought forward, the carbon dioxide (CO2) injection flow rate is decreased. Through this, the carbon dioxide (CO2) injection flow rate can be automatically controlled in real time.

[0127] Accordingly, these rates of density change are monitored in real time, and carbon dioxide (CO2) If the density does not rise for more than 5 minutes during injection, that is, if it remains below the rate of increase threshold for more than 5 minutes, it is determined that carbonation is complete.

[0128] Meanwhile, under the same carbon dioxide (CO2) injection flow rate conditions, the higher the solid content, the more uneven the reaction rate and the more intense the exothermic reaction may become.

[0129] In the case of the real-time carbonation degree control system (100) for concrete recovery water according to an embodiment of the present invention, as a solid content limiting condition, for example, by controlling the solid content within a set range of 12% or less, a uniform reaction can be maintained.

[0130] For this solid content control method, it is preferable to measure the density of the recovered water with a densimeter and estimate the solid content according to the aforementioned [Equation 3] to [Equation 8], and if it exceeds the set range, to inject additional clean water (ordinary water) into the recovered water storage tank (110), which is the reactor, to control the amount of solid content.

[0131] In addition, in the case of the real-time carbonation degree control system (100) for concrete recovery water according to an embodiment of the present invention, the carbonation degree is evaluated comprehensively by monitoring the following three items in real time, namely, density change, pH change, and temperature change, as criteria for determining the carbonation degree and complete carbonation.

[0132] Specifically, regarding density change, if the expected maximum density value is reached during carbon dioxide (CO2) injection, it is determined that the carbonation reaction is complete. That is, if there is no further increase for 5 minutes or more after the density has increased to a certain level during carbon dioxide (CO2) injection, it is determined that the carbonation reaction is complete.

[0133] Here, the above-mentioned maximum density value is a density value obtained by calculating the above-mentioned [Equation 3] to [Equation 8] in reverse order from the maximum degree of carbonation obtained through repetitive experiments in the laboratory, and is derived through the conventional thermogravimetric analysis method.

[0134] Next, regarding pH changes, since a sharp drop in pH occurs in the later stages of the reaction compared to the beginning, it can be used as an indicator of whether the maximum carbonation has been reached; however, it is difficult to estimate the real-time carbonation level during the intermediate reaction process.

[0135] The pH of the concrete recovery water is measured in real time using an inline pH meter (140). While the carbonation reaction is in progress, the concrete recovery water generally maintains a high alkalinity of pH 9 to 11, but when it reaches the maximum degree of carbonation, the pH drops rapidly to 7 or lower, so continuous real-time measurement is essential to capture these pH changes.

[0136] At this time, the inline method can immediately detect changes in pH without time delay even in the flow state within the reactor, which is the recovery water storage tank (110), so the time at which the maximum carbonation is reached can be clearly determined.

[0137] Through this, the end point of the carbonation reaction can be quantitatively determined, and the degree of carbonation can be comprehensively evaluated together with density and temperature data.

[0138] Next, regarding temperature change, the rate of temperature change can be used to determine the termination of the reaction when the temperature converges to a certain level after the reaction heat has risen; however, it is used as a supplementary means of judgment compared to the rates of pH change and density change.

[0139] At this time, in order to measure the accurate temperature, the temperature of the recovered water inside the recovered water storage tank (110), where carbon dioxide (CO2) is injected and a reaction takes place, must be measured directly. On the other hand, the temperature value measured in real time by the inline density meter (150) or inline pH meter (140) may be measured lower than the actual temperature of the recovered water storage tank (110).

[0140] Therefore, since the concrete recovery water transferred from the recovery water storage tank (110) to the inline density meter (150) is affected by external cooling, it is desirable to utilize the real-time value of the temperature sensor (120) inside the recovery water storage tank (110) for accurate reaction heat measurement.

[0141] In other words, in the case of the real-time carbonation degree control system (100) for concrete recovery water according to an embodiment of the present invention, when the density value reaches the maximum density value, it is primarily determined that the maximum carbonation degree has been reached, and additionally, when it is confirmed that the temperature no longer rises and the measured pH drops below the field correction threshold (pH), it is finally determined that the maximum carbonation degree has been reached. The carbonation degree is calculated based on the density value at this time.

[0142] Ultimately, the real-time carbonation degree control system (100) for concrete recovery water according to an embodiment of the present invention considers the carbonation reaction of the concrete recovery water to have ended when all three items—density change, pH change, and temperature change—converge or remain unchanged, and can calculate the carbonation degree based on the density value at that time.

[0143] Meanwhile, FIG. 7 is a detailed configuration diagram of a control panel in a real-time carbonation degree control system for concrete recovery water according to an embodiment of the present invention.

[0144] Referring to FIG. 7, in a real-time carbonation degree control system for concrete recovery water according to an embodiment of the present invention, the control panel (160) comprises a recovery water solid content and volume measurement analysis unit (161), a reaction time setting unit (162), a carbon dioxide injection flow rate determination unit (163), a carbonation degree and temperature prediction unit (164), an operation start unit (165), a real-time temperature, pH and density measurement value analysis unit (166), a prediction and real-time carbonation degree comparison unit (167), a carbon dioxide injection flow rate control unit (168), and a target carbonation degree determination unit (169).

[0145] The analysis unit (161) for measuring the solid content and volume of the recovered water analyzes the solid content and volume of the recovered concrete water measured in the recovered water storage tank (110) before injecting carbon dioxide (CO2).

[0146] Specifically, the above-mentioned analysis unit (161) for measuring the amount and volume of solids in the recovered water analyzes the amount of solids and the total volume contained in the concrete recovered water measured before the carbonation reaction begins, wherein the amount of solids is measured by density or the drying method, and the volume of solids is measured by the water level gauge or weight of the recovered water storage tank (110).

[0147] The reaction time setting unit (162) sets a target reaction time to reach the target carbonation level of the concrete recovery water in the recovery water storage tank (110).

[0148] Specifically, the carbon dioxide injection flow rate determining unit (163) sets the carbon dioxide (CO2) injection rate within an experimentally obtained optimal flow rate range to determine the carbon dioxide (CO2) injection flow rate suitable for the set target carbonation degree and target reaction time.

[0149] The carbon dioxide injection flow rate determining unit (163) determines the carbon dioxide (CO2) injection flow rate injected into the recovery water storage tank (110).

[0150] Specifically, in the real-time temperature, pH, and density measurement control unit (166), the real-time density is continuously measured by an inline density meter (150) of the recovered water circulated through the impeller pump (130), and the carbonation progress is determined by analyzing the density increase trend; the real-time pH is continuously measured in real-time using an inline pH meter (140) to immediately capture pH changes; and the real-time temperature is directly measured by a temperature sensor (120) of the recovered water inside the recovered water storage tank (110), which is a reactor in which carbon dioxide (CO2) is injected and a reaction takes place.

[0151] The carbonation degree and temperature prediction unit (164) predicts the carbonation degree and temperature of the concrete recovery water based on a reference model, which is reference experimental data, by the control panel (160).

[0152] Specifically, the carbonation degree and temperature prediction unit (164) uses the measured solid content, volume, and carbon dioxide (CO2) injection flow rate as input values ​​to predict changes in carbonation degree and temperature over time based on a reference model, which is experimental data built in advance, and tracks and corrects the progress of the actual reaction by synchronizing the reference data of the reference model with the real-time measurement data.

[0153] The operation initiation unit (165) starts the concrete recovery water treatment operation according to the set conditions of the target reaction time, carbon dioxide (CO2) injection flow rate, and limit temperature.

[0154] The real-time temperature, pH, and density measurement analysis unit (166) analyzes the density, pH, and temperature measured in real time in response to the concrete recovery water treatment operation.

[0155] The prediction and real-time carbonation comparison unit (167) compares the predicted carbonation level with the real-time carbonation level.

[0156] Specifically, the prediction and real-time carbonation degree comparison unit (167) evaluates the progress of the reaction by comparing the carbonation degree measured in real-time based on the density, pH, and temperature with the predicted value by the reference model, and automatically corrects the reaction path to maintain a stable carbonation degree through this comparison process.

[0157] The carbon dioxide injection flow rate control unit (168) controls the carbon dioxide (CO2) flow rate according to the degree of carbonation and the limit temperature.

[0158] Here, the carbon dioxide injection flow rate control unit (168) is a control item for simultaneously ensuring reaction efficiency and ready-mix concrete quality, and the limiting temperature is set to a range of 35 to 40°C.

[0159] The target carbonation level determination unit (169) determines that the carbonation of the concrete recovery water is complete when the target carbonation level is reached.

[0160] Specifically, the target carbonation degree determination unit (169) determines whether the expected maximum density value is reached or the density increase remains stagnant for more than 5 minutes during carbon dioxide (CO2) injection, based on three conditions of density change, pH change, and temperature change, determines whether the measured pH drops below the field correction threshold (pH), for example, pH 7 or lower, and determines whether the internal temperature of the recovered water storage tank (110) converges within a certain range after rising, and if all three conditions are satisfied, determines that the carbonation of the recovered concrete water is complete.

[0161] Meanwhile, FIG. 8a is a drawing showing a general-shaped impeller pump, and FIG. 8b is a drawing showing an impeller pump applied to a real-time carbonation degree control system for concrete recovery water according to an embodiment of the present invention.

[0162] As shown in Fig. 8a, in the case of a pump with a general shape, it is desirable to limit its use because there is a risk of wear due to the impeller blades coming into contact with the casing.

[0163] That is, in the case of the impeller pump applied to the real-time carbonation level control system of concrete recovery water according to an embodiment of the present invention, as shown in FIG. 8b, the casing and the blades of the impeller do not come into contact, and accordingly, the risk of wear is low.

[0164] Meanwhile, in the past, a certain amount of recycled water was mixed with fresh water and used in ready-mix concrete production. The KS F 4009 standard stipulates that recycled water may be used within a range where the solid content contained in the recycled water does not exceed 3% of the weight of the binder (cement + fly ash + slag, etc.).

[0165] However, since it is difficult to measure the solid content of the recovered water in real time at the site, the initially measured solid content value is continuously used or the solid content of the recovered water is managed based on the experience of the quality manager.

[0166] At this time, the amount of solids in the recovered water varies significantly, ranging from as little as 6% to as much as 30%. Therefore, if recovered water is used in ready-mix concrete production according to conventional methods, it is very difficult to maintain consistent physical properties of the concrete (e.g., fluidity, compressive strength, etc.), and consequently, there are difficulties in quality control of the ready-mix concrete.

[0167] Accordingly, according to the real-time carbonation degree control system for concrete recycled water according to the embodiment of the present invention, solid content can be managed by monitoring the solid content that changes over time, so the quality of ready-mix concrete can be easily managed even when using recycled water.

[0168] Ultimately, according to an embodiment of the present invention, the limitations of pH measurement alone can be compensated for, and the entire process of the reaction can be evaluated through a combined analysis of density, temperature, and pH.

[0169] In addition, it can maximize the efficiency of carbon dioxide (CO2) injection and prevent overheating and incomplete reactions.

[0170] In addition, the carbonation system can be optimized through real-time data-based process control, and quality consistency can be improved during the manufacture of recycled concrete by automatically determining the complete carbonation status of the recovered water.

[0171] In addition, it can quantify the carbon dioxide (CO2) reduction effect and contribute to the demonstration and standardization of CCU construction material processes.

[0172] [Operation Method of Real-time Carbonation Control System for Recovered Concrete Water]

[0173] FIG. 9 is a flowchart illustrating the operation method of a real-time carbonation degree control system for concrete recovery water according to an embodiment of the present invention.

[0174] Referring to FIG. 9, the method of operating a real-time carbonation degree control system for concrete recovery water according to an embodiment of the present invention first measures the solid content and volume of concrete recovery water in a recovery water storage tank (110) before injecting carbon dioxide (CO2) (S110).

[0175] Specifically, before starting the carbonation reaction, the content and total volume of solids, such as cement fine particles, contained in the concrete recovery water are measured. At this time, the solid content is measured by density or the drying method, and the volume of solids can be measured by the water level gauge or weight of the recovery water storage tank (110). These measured values ​​serve as basic data for calculating the reaction amount, injection flow rate, and reaction time required for carbon dioxide (CO2) injection. For example, as the solid content increases, the reaction heat increases and the reaction rate slows down, so it is used as a standard for carbon dioxide (CO2) injection conditions and reaction control in subsequent processes.

[0176] Next, a target reaction time is set to reach the target carbonation level of the concrete recovery water in the recovery water storage tank (110) (S120).

[0177] Specifically, the manager sets the desired target carbonation level and target reaction time. For example, the target reaction time is set as "achieving 100% carbonation level in 40 minutes."

[0178] Here, 100% carbonation is defined based on the maximum CO2 fixation amount obtained by analyzing a sample injected with carbon dioxide (CO2) by thermogravimetric analysis (TG) through multiple experiments until carbonation no longer proceeds.

[0179] These reference values ​​are used as reference values ​​for setting the target carbonation level during actual operation, and the real-time carbonation level control system (100) for concrete recovery water according to an embodiment of the present invention performs injection time and flow rate control based on them. The target carbonation level and target reaction time set at this stage serve as reference points for time-based control, and subsequently determine the carbon dioxide (CO2) injection flow rate and are used as criteria for a real-time control algorithm.

[0180] Next, the amount of carbon dioxide (CO2) injected into the above-mentioned recovery water storage tank (110) is determined (S130).

[0181] Specifically, based on the solid content and volume of the concrete recovery water measured in the aforementioned step S110, a carbon dioxide (CO2) injection flow rate suitable for the target carbonation degree and target reaction time set in step S120 is determined.

[0182] In this case, if the carbon dioxide (CO2) injection flow rate is too low, the reaction time increases excessively, and the consumption of carbon dioxide (CO2) increases unnecessarily to achieve the same degree of carbonation. On the other hand, if the carbon dioxide (CO2) injection flow rate is too high, excessive exothermic reaction and reaction non-uniformity occur due to the rapid reaction. Furthermore, the carbon dioxide (CO2) injection rate has inverse effects on the degree of carbonation and the final amount of carbon dioxide (CO2) fixed.

[0183] In addition, if the carbon dioxide (CO2) injection rate is fast, the carbonation reaction proceeds rapidly, but because the carbonation reaction occurs rapidly at the surface layer of the recovered water storage tank (110), an unreacted area remains inside the recovered water storage tank (110), so complete carbonation may not be achieved.

[0184] On the other hand, if the carbon dioxide (CO2) injection rate is slow, the carbonation reaction proceeds slowly, but the carbon dioxide (CO2) penetrates into the solids, enabling complete carbonation. However, the reaction time and the total amount of carbon dioxide (CO2) injected may increase.

[0185] Accordingly, the real-time carbonation degree control system (100) for concrete recovery water according to an embodiment of the present invention must set an optimal injection speed by considering both the operating efficiency and the final fixed amount. Ultimately, it is desirable to set the carbon dioxide (CO2) injection speed within the optimal flow rate range obtained experimentally, and this injection speed value is subsequently used as a reference value for the real-time control step.

[0186] Next, the carbonation degree and temperature of the concrete recovery water are predicted based on a reference model, which is standard experimental data (S140).

[0187] Specifically, using the solid content, volume, and carbon dioxide (CO2) injection flow rate measured as described above as input values, the change in carbonation degree and temperature over time is predicted based on a reference model, which is experimental data constructed in advance.

[0188] Here, the experimental data of the above reference model was obtained through repeated experiments using standard recovered water composed of 100% cement, and is reference data that quantitatively identifies reaction characteristics and carbonation rate.

[0189] Meanwhile, since it is difficult to analyze the accurate composition in real time because impurities such as fine aggregate or fine particles are mixed into the concrete recovery water during actual operation, the real-time carbonation degree control system (100) according to the embodiment of the present invention tracks and corrects the progress of the actual reaction by synchronizing the reference data of the reference model with real-time measurement data (density, pH, and temperature).

[0190] This carbonation degree and temperature prediction step is a key procedure for stably managing carbon dioxide (CO2) reaction efficiency as a synchronized control process connecting the reference reaction system and the actual reaction system.

[0191] Next, concrete recovery water treatment operation is started according to the set conditions, such as the target reaction time, carbon dioxide (CO2) injection flow rate, and limit temperature (S150).

[0192] Next, density, pH, and temperature are measured in real time in response to the concrete recovery water treatment operation (S160).

[0193] Specifically, during concrete recovery water treatment operation, the following three items are measured in real time. For example, real-time density is continuously measured by an inline density meter (150) of the recovery water circulated through the impeller pump (130), and the degree of carbonation progress can be determined by analyzing the density increase trend.

[0194] In addition, real-time pH is measured in real time using an inline pH meter (140). At this time, since the concrete recovery water maintains a high alkalinity of pH 11 or higher while carbonation is in progress, and the pH drops rapidly to 7 or lower at the time carbonation is complete, real-time continuous measurement is essential to immediately capture this pH change.

[0195] In addition, the real-time temperature is directly measured by a temperature sensor (120) using the temperature of the recovered water inside the recovered water storage tank (110), which is a reactor in which carbon dioxide (CO2) is injected and a reaction takes place. At this time, since the concrete recovered water sample that is sampled and transferred to the inline density meter (150) is affected by external cooling, it is preferable to use the measurement value of the temperature sensor (120) installed inside the recovered water storage tank (110), which is the reactor, rather than using the temperature value inside the inline density meter (150).

[0196] Next, the predicted carbonation level and the real-time carbonation level are compared (170).

[0197] Specifically, the real-time carbonation degree control system (100) for concrete recovery water according to an embodiment of the present invention evaluates the progress of the reaction by comparing the real-time carbonation degree measured based on density, pH, and temperature with the predicted value by the reference model of step S140 described above.

[0198] If the reaction rate is slower than the predicted value, the carbon dioxide (CO2) injection flow rate is increased, and if the reaction rate is faster than the predicted value, the carbon dioxide (CO2) injection flow rate is decreased to prevent overheating or low carbonation. Through this comparison process, the real-time carbonation degree control system (100) of concrete recovery water according to the embodiment of the present invention can maintain a stable carbonation degree by automatically correcting the reaction path.

[0199] Next, the carbon dioxide (CO2) flow rate is controlled according to the degree of carbonation and the limit temperature (S180).

[0200] Specifically, the carbon dioxide (CO2) injection flow rate is automatically adjusted based on the difference between real-time data and predicted values. In this process, the temperature limit is a key control factor designed to simultaneously guarantee reaction efficiency and ready-mix concrete quality.

[0201] In addition, the carbonation reaction between carbon dioxide (CO2) and solids in the recovered water has the characteristic that the lower the temperature, the higher the efficiency, and the reaction rate and efficiency decrease as the temperature increases. Also, if the reaction temperature rises excessively, it negatively affects the physical properties of the recovered water, such as slump reduction and abnormal solidification, when the recovered water is used as mixing water for ready-mix concrete; therefore, the limiting temperature is generally set in the range of 35 to 40°C.

[0202] Accordingly, in the case of the real-time carbonation degree control system (100) for concrete recovery water according to an embodiment of the present invention, if the temperature rises above a limiting temperature, the carbon dioxide (CO2) injection flow rate is reduced or temporarily blocked. Conversely, if the reaction stagnates or the temperature is excessively low, the carbon dioxide (CO2) injection flow rate is temporarily increased.

[0203] In the case of the real-time carbonation degree control system (100) for concrete recovery water according to an embodiment of the present invention, the carbonation reaction efficiency can be optimized through such temperature-based control, and the recovery water can be maintained at a stable quality that allows it to be recycled as mixing water for concrete.

[0204] Next, when the target carbonation level is reached, it is determined that the carbonation of the concrete recovery water is complete (S190).

[0205] Specifically, it is determined that the carbonation of the concrete recovery water is complete when all three conditions regarding the aforementioned density change, pH change, and temperature change are satisfied. That is, it is determined whether the expected maximum density value is reached or whether the density increase remains stagnant for more than 5 minutes during the injection of carbon dioxide (CO2), and also whether the measured pH drops below the field correction threshold (pH), for example, to 7 or lower, and whether the internal temperature of the recovery water storage tank (110), which is the reactor, converges within a certain range after rising.

[0206] When all three of these conditions are satisfied, it is determined that the carbonation reaction of the concrete recovery water has ended, and the data at this point is automatically stored in the real-time carbonation degree control system (100) of the concrete recovery water according to an embodiment of the present invention and can be used as model correction data (Feedback Reference) during the next operation.

[0207] Meanwhile, FIG. 10 is a diagram illustrating a carbonation reference model according to the carbon dioxide (CO2) injection flow rate of recovered water with a solid content of 6% in a method of operating a real-time carbonation control system for recovered concrete water according to an embodiment of the present invention.

[0208] In addition, in the operation method of the real-time carbonation degree control system for concrete recovery water according to an embodiment of the present invention, when the carbon dioxide (CO2) injection flow rate is 15 L / min for 30 L of recovery water with a solid content of 6%, the real-time carbonation degree model can be exemplarily represented as shown in [Table 2].

[0209]

[0210] Meanwhile, FIG. 11 is a diagram illustrating the control of carbon dioxide (CO2) injection flow rate when a difference occurs from the expected carbonation completion time in the operation method of a real-time carbonation degree control system for concrete recovery water according to an embodiment of the present invention.

[0211] FIG. 12 is a diagram illustrating the control of carbon dioxide (CO2) injection flow rate when the recovered water approaches a limiting temperature in the operation method of a real-time carbonation degree control system for recovered concrete water according to an embodiment of the present invention.

[0212] Ultimately, according to an embodiment of the present invention, it can be utilized by connecting it to existing ready-mix concrete facilities and water recovery facilities, and can be input into a PLC (programmable logic controller) that implements a real-time carbonation degree control system for concrete water recovery, thereby being utilized as an automated production technology for mineral carbonated water recovery.

[0213] In other words, the recycling of concrete wastewater is currently restricted due to the difficulty of managing solid content. Although KS standards (KS F 4009) allow for the use of up to 3% of sludge solids in the cement binder, due to practical issues, an appropriate amount of wastewater is used in the mixing water. That is, it is difficult to measure the solid content ratio, which changes every hour, in real time.

[0214] In addition, the solid content of the recovered water varies significantly depending on various variables such as the production volume of concrete and the number of ready-mix concrete cycles, and when this is used as mixing water for concrete, the physical properties of the concrete change significantly. This is due to unhydrated cement particles in the recovered water, which have a significant impact on the setting time and slump flow.

[0215] Accordingly, according to an embodiment of the present invention, by managing the solid content of the concrete recovery water and reacting unhydrated cement particles with carbon dioxide (CO2), the quality of the concrete recovery water can be stabilized, thereby enabling active recycling.

[0216] In addition, by reacting carbon dioxide (CO2) with the recovered water sludge to induce a permanent mineralization reaction, using it as concrete mixing water enables the storage of carbon dioxide (CO2) within the concrete, thereby contributing to carbon reduction.

[0217] In addition, when carbon dioxide (CO2) mineral carbonation recovered water is used as mixing water for concrete, an equivalent level of compressive strength can be achieved even if cement is reduced by the amount of solid content of the recovered water, thereby reducing the amount of cement used in concrete production and simultaneously increasing the recycling rate of sludge.

[0218] In addition, ready-mix concrete companies can reduce costs by decreasing cement usage. For example, the future domestic ready-mix concrete market (annual 140 million m³) 3 If this technology is applied to ), the carbon dioxide (CO2) storage capacity (2 kg / m³) 3 Reduction in cement due to ) and increase in compressive strength (10kg / m 3 Since it can bring about the effects of ), the annual carbon dioxide (CO2) due to direct and indirect effects The reduction is expected to be 1.68 million tons, which accounts for approximately 16.8% of the 10 million ton target for the CCUS sector within the domestic 2030 greenhouse gas reduction target.

[0219] The foregoing description of the present invention is for illustrative purposes only, and those skilled in the art will understand that other specific forms can be easily modified without altering the technical spirit or essential features of the present invention. Therefore, the embodiments described above should be understood as illustrative in all respects and not restrictive. For example, each component described as a single unit may be implemented in a distributed manner, and components described as distributed may likewise be implemented in a combined form.

[0220] The scope of the present invention is defined by the claims set forth below rather than by the detailed description above, and all modifications or variations derived from the meaning and scope of the claims and equivalent concepts thereof should be interpreted as being included within the scope of the present invention. Explanation of the symbols

[0221] 100: Carbonation Control System 110: Recovered water storage tank (reactor) 120: Temperature sensor 130: Impeller pump 140: Inline pH meter 150: Inline Densitometer 160: Control Panel 161: Analysis Unit for Measurement of Solid Content and Volume of Recovered Water 162: Response time setting section 163: Carbon dioxide injection flow rate determining unit 164: Carbonation Degree and Temperature Prediction Section 165: Operation start section 166: Real-time temperature, pH, and density measurement analysis unit 167: Prediction and Real-time Carbonation Comparison Section 168: Carbon dioxide injection flow rate control unit 169: Target Carbonation Determination Unit 170: Carbon Dioxide Injection Flow Control System (MFC)

Claims

Claim 1 A reactor for storing and processing concrete recovery water, comprising: a recovery water storage tank (110) into which carbon dioxide (CO2) is injected to recycle the concrete recovery water; a temperature sensor (120) installed in the recovery water storage tank (110) to measure the temperature of the concrete recovery water in real time; an impeller pump (130) that supplies the concrete recovery water stored in the recovery water storage tank (110) to an inline densimeter (150) and an inline pH meter (140) through a pipe; an inline pH meter (140) that measures the pH of the concrete recovery water transferred through the impeller pump (130) in real time; an inline densimeter (150) that measures the density of the concrete recovery water transferred through the impeller pump (130) in real time; and a control panel (160) which is a data collection and analysis module with a carbonation degree calculation algorithm embedded therein, which evaluates the reaction characteristics of the concrete recovery water in which carbonation reaction proceeds by injecting carbon dioxide (CO2) by integrating multiple physical property values ​​of density, pH, and temperature to evaluate in real time and sets the optimal carbon dioxide (CO2) injection flow rate.The apparatus includes a carbon dioxide injection flow rate control device (170) that injects carbon dioxide (CO2) supplied to the recovery water storage tank (110) under the control of the control panel (160), wherein the control panel (160) primarily determines that the maximum carbonation level has been reached when the density value measured by the inline densimeter (150) reaches the maximum density value, and additionally determines that the maximum carbonation level has been reached when it is confirmed that the temperature no longer rises and the measured pH drops below the field correction threshold (pH), and calculates the carbonation level based on the density value, and the control panel (160) monitors the rate of change of the density value measured by the inline densimeter (150) in real time and compares the carbonation level predicted by the reference model with the real-time carbonation level, and if it is determined that the expected time to reach the target carbonation level is delayed, it increases the carbon dioxide (CO2) injection flow rate, and if it is determined that the expected time to reach the target carbonation level is advanced, the carbon dioxide (CO2) A real-time carbonation degree control system for concrete recovery water that reduces the injection flow rate, and if the internal temperature of the recovery water storage tank (110) measured by the temperature sensor (120) rises above a limit temperature, reduces or temporarily blocks the carbon dioxide (CO2) injection flow rate, and the limit temperature is set to a range of 35 to 40℃. Claim 2 In claim 1, the control panel (160) comprises: a solid content and volume measurement analysis unit (161) that analyzes the solid content and volume of concrete recovery water measured in the recovery water storage tank (110) before carbon dioxide (CO2) injection; a reaction time setting unit (162) that sets a target reaction time to reach the target carbonation level of the concrete recovery water in the recovery water storage tank (110); a carbon dioxide injection flow rate determination unit (163) that determines the carbon dioxide (CO2) injection flow rate injected into the recovery water storage tank (110); a carbonation level and temperature prediction unit (164) in which the control panel (160) predicts the carbonation level and temperature of the concrete recovery water based on a reference model, which is reference experimental data; an operation initiation unit (165) that starts the concrete recovery water treatment operation according to the set conditions of the target reaction time, carbon dioxide (CO2) injection flow rate, and limit temperature; a real-time temperature, pH, and density measurement analysis unit (166) that analyzes the density, pH, and temperature measured in real-time in response to the concrete recovery water treatment operation; and a prediction unit. A real-time carbonation level control system for concrete recovery water, comprising: a prediction and real-time carbonation level comparison unit (167) that compares the carbonation level with the real-time carbonation level; a carbon dioxide injection flow rate control unit (168) that controls the carbon dioxide (CO2) flow rate according to the carbonation level and limit temperature; and a target carbonation level determination unit (169) that determines that the carbonation of the concrete recovery water is complete when the target carbonation level is reached. Claim 3 In paragraph 2, the solid content and volume measurement analysis unit (161) of the concrete recovery water analyzes the solid content and total volume contained in the concrete recovery water measured before the carbonation reaction begins, wherein the solid content is measured by density or drying method, and the solid volume is measured by a water level gauge or a weight gauge (weight measurement) of the concrete recovery water storage tank (110), characterized by a real-time carbonation degree control system for concrete recovery water. Claim 4 In paragraph 2, the carbon dioxide injection flow rate determining unit (163) is characterized by setting the carbon dioxide (CO2) injection rate within an optimal flow rate range experimentally obtained to determine the carbon dioxide (CO2) injection flow rate suitable for the set target carbonation degree and target reaction time, in a real-time carbonation degree control system for concrete recovery water. Claim 5 In paragraph 2, the carbonation degree and temperature prediction unit (164) predicts changes in carbonation degree and temperature over time based on a reference model, which is experimental data established in advance, using the measured solid content, volume, and carbon dioxide (CO2) injection flow rate as input values, and tracks and corrects the progress of the actual reaction by synchronizing the reference data of the reference model with the real-time measurement data, thereby forming a real-time carbonation degree control system for concrete recovery water. Claim 6 In the second paragraph, the real-time temperature, pH, and density measurement control unit (166) is characterized by continuously measuring the real-time density of the recovered water circulated through the impeller pump (130) using an inline density meter (150) and determining the degree of carbonation progress by analyzing the density increase trend, continuously measuring the real-time pH using an inline pH meter (140) to immediately capture changes in pH, and directly measuring the temperature of the recovered water inside the recovered water storage tank (110), which is a reactor in which carbon dioxide (CO2) is injected and a reaction takes place, using a temperature sensor (120). Claim 7 delete Claim 8 delete Claim 9 In paragraph 2, the target carbonation degree determination unit (169) determines, based on three conditions according to density change, pH change, and temperature change, whether the expected maximum density value is reached or the density increase remains stagnant for more than 5 minutes during carbon dioxide (CO2) injection, whether the measured pH falls below the field correction threshold (pH), and whether the internal temperature of the recovered water storage tank (110) converges within a certain range after rising, and if all three conditions are satisfied, determines that the carbonation of the recovered concrete water is complete. Claim 10 delete Claim 11 In a method of operating a real-time carbonation degree control system for concrete recovery water using the real-time carbonation degree control system for concrete recovery water according to claim 1, a) a step of measuring the solid content and volume of concrete recovery water in a recovery water storage tank (110) before injecting carbon dioxide (CO2); b) a step in which the control panel (160) sets a target reaction time to reach the target carbonation level of the concrete recovery water in the recovery water storage tank (110); c) a step in which the control panel (160) determines the carbon dioxide (CO2) injection flow rate to be injected into the recovery water storage tank (110); d) a step in which the control panel (160) predicts the carbonation level and temperature of the concrete recovery water based on a reference model, which is reference experimental data; e) a step in which the control panel (160) starts a concrete recovery water treatment operation according to the set conditions of the target reaction time, carbon dioxide (CO2) injection flow rate, and limit temperature; f) a step in which the density, pH, and temperature are measured in real time in response to the concrete recovery water treatment operation; g) a step in which the control panel (160) compares the predicted carbonation level with the real-time carbonation level; h) a step in which the control panel (160) controls the carbon dioxide (CO2) flow rate according to the carbonation level and limit temperature. and i) a method of operating a real-time carbonation level control system for concrete recovery water, comprising the step of determining that the carbonation of the concrete recovery water is complete when the control panel (160) reaches a target carbonation level. Claim 12 delete Claim 13 A method of operating a real-time carbonation degree control system for concrete recovery water, characterized in that, in step a) above, before starting the carbonation reaction, the content of solids contained in the concrete recovery water and the total volume are measured, wherein the content of solids is measured by density or the drying method, and the volume of solids is measured by the water level gauge or weight of the recovery water storage tank (110). Claim 14 A method of operating a real-time carbonation degree control system for recovered concrete water, characterized in that, in step b) above, the 100% carbonation degree is defined based on the Maximum CO2 Fixation Amount obtained by analyzing a sample injected with carbon dioxide (CO2) by thermogravimetric analysis (TG) through multiple experiments until carbonation no longer proceeds. Claim 15 A method of operating a real-time carbonation degree control system for concrete recovery water, characterized in that, in step c) above, the carbon dioxide (CO2) injection rate is set within an experimentally obtained optimal flow rate range to determine the carbon dioxide (CO2) injection rate suitable for the set target carbonation degree and target reaction time. Claim 16 A method of operating a real-time carbonation degree control system for recovered concrete water, characterized in that, in step d) above, the measured solid content, volume, and carbon dioxide (CO2) injection flow rate are used as input values ​​to predict changes in carbonation degree and temperature over time based on a reference model, which is experimental data established in advance, and the actual progress of the reaction is tracked and corrected by synchronizing the reference data of the reference model with the real-time measurement data. Claim 17 A method of operating a real-time carbonation degree control system for concrete recovery water, characterized in that, in step f) above, real-time density is continuously measured using an inline density meter (150) for the recovery water circulated through an impeller pump (130), and the degree of carbonation is determined by analyzing the density increase trend, real-time pH is continuously measured in real-time using an inline pH meter (140) to immediately capture pH changes, and real-time temperature is directly measured using a temperature sensor (120) for the temperature of the recovery water inside a recovery water storage tank (110), which is a reactor in which carbon dioxide (CO2) is injected and a reaction takes place. Claim 18 delete Claim 19 delete Claim 20 A method of operating a real-time carbonation degree control system for concrete recovery water according to claim 11, characterized in that, in step i), three conditions regarding density change, pH change, and temperature change are determined by determining whether the expected maximum density value is reached or the density increase remains stagnant for more than 5 minutes during carbon dioxide (CO2) injection, determining whether the pH drops to 7 or lower, and determining whether the internal temperature of the recovery water storage tank (110) converges within a certain range after rising, and determining that the carbonation of the concrete recovery water is completed when all three conditions are satisfied.

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