Apparatus and method for recovering boric acid from radioactive boric acid waste

Abstract

The present invention relates to an apparatus and method for recovering boric acid from radioactive boric acid waste, the apparatus and method recovering boric acid from radioactive boric acid waste by using a liquid-phase hydration reaction of CaCl2 in a boric acid esterification reaction. In addition, the present invention can effectively remove water generated by the boric acid esterification reaction and more efficiently separate boric acid contained in radioactive boric acid waste by comprising: an esterification reactor in which a boric acid esterification process and an evaporation process sequentially take place, the evaporation process evaporating and discharging a reaction product generated by a boric acid esterification reaction; a boric acid recovery reactor in which the reaction product discharged from the esterification reactor is accommodated, and a boric acid recovery process for recovering boric acid from the accommodated reaction product and discharging ethanol takes place; and an ethanol purification reactor in which ethanol discharged from the boric acid recovery reactor is accommodated, and an ethanol recovery process for purifying and recovering the accommodated ethanol takes place.

Description

Apparatus and method for recovering boric acid from radioactive boric acid waste

[0001] The present invention relates to an apparatus and method for recovering boric acid from radioactive boric acid waste by utilizing a liquid phase hydration reaction of CaCl2 in a boric acid esterification reaction process.

[0002] Generally, a large amount of liquid radioactive waste is generated during operation at nuclear power plants, and among this is radioactive boric acid waste containing boric acid (H3BO3).

[0003] In addition, at nuclear power plants, radioactive boric acid waste is pulverized using evaporators and concentrated wastewater drying equipment, and the pulverized radioactive boric acid waste is stored for a long time in sealed containers because there is no special treatment method.

[0004] Domestic nuclear power plants have mainly processed radioactive boric acid waste using a cement-based solidification method, but cement-based solidification processing is being discontinued due to problems such as the volume of the cement-based solidified waste increasing by more than 10 times compared to the disposal amount, the generation of free water, and reduced safety of disposal of the solidified waste.

[0005] In response to this, paraffin solidification technology was applied as an alternative; however, paraffin solidified bodies are flammable substances that are unsuitable for disposal facility acceptance conditions, and due to their low leaching resistance, they are assessed as unable to meet the acceptance criteria for solidified body disposal.

[0006] Therefore, the use of high-integrity containers is being proposed as a method to dispose of radioactive boric acid waste currently being stored for a long time. However, there is a problem in that when the radioactive boric acid waste comes into contact with groundwater after the lifespan of the high-integrity containers is exhausted, it dissolves in the water to produce boric acid, which can contaminate the groundwater.

[0007] In addition, when using high-integrity containers, the amount of radioactive boric acid waste processed increases significantly, which leads to a problem of lower utilization of disposal sites and a significant increase in disposal costs.

[0008] Consequently, new technologies and devices are required to fundamentally prevent the possibility of future environmental contamination around radioactive waste disposal sites, enhance utilization efficiency, and simultaneously reduce disposal costs.

[0009] Meanwhile, the technology forming the background of the present invention is disclosed in Korean Published Patent Application No. 10-2000-0053644 (published August 25, 2000), Korean Registered Patent Application No. 10-1722546 (registered March 28, 2017), and Korean Published Patent Application No. 10-2023-0030986 (published March 7, 2023).

[0010] The present invention was devised in consideration of the above-mentioned problems, and aims to provide a boric acid recovery apparatus and method for radioactive boric acid waste that can increase the separation efficiency of boric acid by removing water generated during the boric acid esterification reaction process when treating radioactive boric acid waste.

[0011] The objectives of the present invention are not limited to those mentioned above, and other unmentioned objectives will be clearly understood by those skilled in the art from the description below.

[0012] The present invention, for achieving the above-mentioned purpose, provides a boric acid recovery apparatus for radioactive boric acid waste comprising: an esterification reactor in which a boric acid esterification process for removing boric acid contained in radioactive boric acid waste by inducing a boric acid esterification reaction and an evaporation process for evaporating and discharging a reaction product generated by the boric acid esterification reaction are sequentially performed; a boric acid recovery reactor in which a boric acid recovery process is performed to receive the reaction product discharged from the esterification reactor, recover boric acid from the received reaction product, and discharge ethanol; and an ethanol purification reactor in which an ethanol recovery process is performed to receive the ethanol discharged from the boric acid recovery reactor and purify and recover the received ethanol.

[0013] In a preferred embodiment, the system further includes a pressure transfer unit connecting the esterification reactor and the boric acid recovery reactor; wherein the pressure transfer unit reduces the pressure inside the esterification reactor during the evaporation process so that the reaction product is evaporated under reduced pressure, and converts the reaction product evaporated under reduced pressure in a gaseous state into a liquid state and transfers it to the boric acid recovery reactor.

[0014] In a preferred embodiment, the apparatus further includes an ethanol transfer unit connecting the boric acid recovery reactor and the ethanol purification reactor; wherein the ethanol transfer unit reduces the pressure inside the boric acid recovery reactor during the boric acid recovery process so that ethanol is evaporated under reduced pressure, and converts the ethanol evaporated under reduced pressure in a gaseous state into a liquid state and transfers it to the ethanol purification reactor.

[0015] In a preferred embodiment, the system further comprises an exhaust gas treatment unit that cools the exhaust gas discharged from the esterification reactor, filters particulate radioactive material contained in the cooled exhaust gas, and discharges the filtered exhaust gas to the outside while monitoring the radiation concentration of the filtered exhaust gas; and the esterification reactor further performs an exhaust process in which, after the evaporation process, the reaction residue remaining after the reaction product is discharged is heated and discharged as exhaust gas containing water and ethanol.

[0016]

[0017] In addition, the present invention relates to a method for recovering boric acid from radioactive boric acid waste, performed in a boric acid recovery apparatus for radioactive boric acid waste, comprising: (a) a step of supplying hot water to a radioactive boric acid waste solution in an esterification reactor to perform a solution treatment when the radioactive boric acid waste is introduced; (b) a step of supplying hydrochloric acid to a radioactive boric acid waste solution in the esterification reactor to induce boric oxidation treatment of metaboric acid and borate compounds and a neutralization reaction with respect to Na ions; (c) a step of drying the radioactive boric acid waste solution in which the boric oxidation treatment and neutralization reaction are completed in the esterification reactor to form boric acid powder; and (d) a step of supplying ethanol to the boric acid powder in the esterification reactor to induce a boric acid esterification reaction, and when the boric acid esterification reaction reaches equilibrium, supplying a hygroscopic agent to accelerate the boric acid esterification reaction. (e) a step of evaporating and discharging the reaction product generated by the boric acid esterification reaction in the esterification reactor, and heating the reaction residue remaining after the reaction product is discharged and discharging it as exhaust gas containing water and ethanol; and (f) a step of heating the reaction product in the boric acid recovery reactor to recover boric acid and discharge ethanol, and purifying and recovering the discharged ethanol in the ethanol purification reactor; the present invention provides a method for recovering boric acid from radioactive boric acid waste.

[0018] By means of the aforementioned problem-solving means, the present invention can effectively remove water generated by the boric acid esterification reaction using calcium chloride (CaCl2) as a hygroscopic agent, and thereby has the effect of increasing the separation efficiency of boric acid contained in radioactive boric acid waste.

[0019] In addition, the present invention can not only enhance the safety of radioactive waste disposal sites by completely removing boron components that are groundwater contaminants, but also has the effect of increasing the decontamination effect by eliminating the possibility of high-temperature volatilization of radioactive materials such as cesium through a low-temperature (300℃) regeneration process of calcium chloride adducts generated by water absorption and ethanol absorption.

[0020] In addition, the present invention has the effect of significantly increasing the volume reduction ratio of radioactive boric acid waste by recycling the absorbent, while simultaneously reducing waste disposal costs.

[0021] In addition, the present invention can maximize the recovery rate of boric acid by converting a borate component containing Na ions into boric acid using hydrochloric acid, and this has the effect of being easily applicable to the boric acid conversion process of metaboric acid or tetraboric acid generated during the drying process of radioactive boric acid waste.

[0022] In addition, the present invention has the effect of increasing economic efficiency by obtaining pure boric acid water from radioactive boric acid waste and making it reusable in nuclear power plants, etc.

[0023] FIG. 1 is a drawing of a boric acid recovery device for radioactive boric acid waste according to the present invention.

[0024] FIG. 2 is a diagram of a method for recovering boric acid from radioactive boric acid waste according to the present invention.

[0025] In the following description, specific details of the invention are provided to provide an overall understanding of the invention, but it will be obvious to those skilled in the art that the invention can be easily practiced without these specific details and by variations thereof.

[0026] Hereinafter, a preferred embodiment according to the present invention will be described in detail with reference to the attached FIGS. 1 and 2, focusing on the parts necessary to understand the operation and function according to the present invention.

[0027]

[0028] FIG. 1 is a drawing of a boric acid recovery device for radioactive boric acid waste according to the present invention.

[0029] Referring to FIG. 1, a boric acid recovery device (10) for radioactive boric acid waste according to one embodiment of the present invention may be configured to include an esterification reactor (100), a pressure reduction transfer unit (200), a boric acid recovery reactor (300), an ethanol transfer unit (400), an ethanol purification reactor (500), and an exhaust gas treatment unit (600).

[0030] The boric acid recovery device (10) for radioactive boric acid waste according to one embodiment of the present invention is used for processing radioactive boric acid waste, and the aforementioned radioactive boric acid waste may include a liquid form of radioactive boric acid waste containing boric acid (H3BO3) and a solid form of radioactive dry waste containing boric acid and metaboric acid, etc.

[0031] The above esterification reactor (100) is provided to perform various processes for the treatment of radioactive boric acid waste, and may be provided in a cylindrical structure with one side open and an internal space formed to accommodate radioactive boric acid waste, but is not limited thereto.

[0032] Additionally, in the esterification reactor (100), a solution process in which hot water is supplied to radioactive boric acid waste to perform solution treatment, a boric oxidation process in which hydrochloric acid is supplied to induce a neutralization reaction with Na ions while boric oxidation treatment of metaboric acid and borate compounds, and a drying process in which boric acid powder is formed through drying can be performed sequentially.

[0033] After that, in the esterification reactor (100), a boric acid esterification process can be performed to remove boric acid contained in radioactive boric acid waste by inducing a boric acid esterification reaction, an evaporation process to evaporate and discharge the reaction product generated by the boric acid esterification reaction, and an exhaust process to heat the reaction residue remaining after the reaction product is discharged and discharge it as exhaust gas containing water and ethanol.

[0034] In addition to the aforementioned internal space, such an esterification reactor (100) may be equipped with a heating section (110), an opening / closing section (120), a stirring section (130), a liquid injection port (140), and a calcium chloride injection port (150).

[0035] The heating unit (110) is for heating the internal space of the esterification reactor (100) and may be formed integrally with the esterification reactor (100) or may be formed in a form coupled to the outside or outer surface of the esterification reactor (100).

[0036] The heating unit (110) may be configured to include an electric heating device and a control device, but is not limited thereto.

[0037] The above opening / closing part (120) is formed on one side of the open side of the esterification reactor (100) and is provided to be opened and closed to open or close the internal space of the esterification reactor (100).

[0038] The opening / closing part (120) is opened when radioactive boric acid waste is introduced, is closed while various processes are being performed, and is opened after the evaporation process or exhaust process is completed to allow for the treatment of residues remaining in the esterification reactor (100).

[0039] The above stirring section (130) is formed in a shape that extends into the internal space of the esterification reactor (100) by passing through the opening / closing section (120), and mixes radioactive dry waste, etc. contained in the internal space of the esterification reactor (100) in various processes, thereby allowing processes or reactions to proceed smoothly.

[0040] The stirring part (130) may be formed with a structure including a blade and a motor, but is not limited thereto.

[0041] The above liquid injection port (140) is provided in the opening / closing part (120) or in a predetermined location of the esterification reactor (100), and functions as a passage capable of supplying a liquid containing hot water and ethanol to the internal space of the esterification reactor (100).

[0042] The calcium chloride injection port (150) may also be provided at a predetermined location of the opening / closing part (120) or the esterification reactor (100), and functions as a passage for supplying calcium chloride (CaCl2) used as a hygroscopic agent.

[0043] The above-described pressure transfer unit (200) connects the esterification reactor (100) and the boric acid recovery reactor (300), and during the evaporation treatment process, the inside of the esterification reactor (100) is reduced to pressure so that the reaction product is evaporated under reduced pressure, and the reaction product evaporated under reduced pressure in a gaseous state is converted into a liquid state and transferred to the boric acid recovery reactor (300). Here, the aforementioned reaction product may include triethyl borate and ethanol produced by the boric acid esterification reaction.

[0044] The pressure reduction transfer unit (200) may be configured to include a pressure reduction transfer pipe (210), a pressure reduction pump (220), a reaction product cooling unit (230), and a cooling water supply pump (240).

[0045] The above-mentioned pressure transfer pipe (210) may be a pipe connecting the esterification reactor (100) and the boric acid recovery reactor (300).

[0046] The above-mentioned pressure reduction pump (220) is connected to one side of the pressure reduction transfer pipe (210) and can be positioned adjacent to the boric acid recovery reactor (300), and can reduce the pressure of the internal space of the esterification reactor (100) by sucking in air through the pressure reduction transfer pipe (210), and can be equipped with a blower device such as a vacuum pump, a blower, and a fan.

[0047] The above reaction product cooling section (230) is formed on the outer surface of the pressure transfer pipe (210) and is formed with a structure in which cooling water flows inside, thereby lowering the temperature of the pressure transfer pipe (210) so that the reaction product being transferred in a gaseous state along the pressure transfer pipe (210) can be converted into a liquid state.

[0048] Such a reaction product cooling unit (230) may be a cooling device that uses cooling water.

[0049] The above cooling water supply pump (240) supplies cooling water at a constant temperature to the reaction product cooling section (230), thereby enabling the cooling water to circulate in the reaction product cooling section (230).

[0050] The above boric acid recovery reactor (300) is provided to perform a boric acid recovery process and may be provided in a cylindrical structure with an internal space formed therein, may receive a reaction product discharged from an esterification reactor (100), and may perform a boric acid recovery process in which boric acid is recovered from the received reaction product and ethanol is discharged.

[0051] In addition to the aforementioned internal space, the boric acid recovery reactor (300) may be equipped with a boric acid water outlet (310), a reactor heating section (320), a demineralized water supply valve (330), and a demineralized water tank (340).

[0052] The above boric acid water discharge port (310) is connected to the outside of the boric acid recovery reactor (300), allowing the boric acid water generated by the boric acid recovery process to be discharged to the outside of the boric acid recovery reactor (300).

[0053] The above reactor heating unit (320) is for heating the internal space of the boric acid recovery reactor (300), and may be formed integrally with the boric acid recovery reactor (300), or may be formed in a form coupled to the outer side or outer surface of the boric acid recovery reactor (300), and may be configured to include an electric heating device and a control device.

[0054] The above demineralized water supply valve (330) is formed between the demineralized water tank (340) and the boric acid recovery reactor (300) and is formed to be openable and closable so as to supply demineralized water stored in the demineralized water tank (340) to the boric acid recovery reactor (300) or to cut off the supply.

[0055] The above deionized water tank (340) stores deionized water and is connected to a boric acid recovery reactor (300), and can supply deionized water to the boric acid recovery reactor (300) for the boric acid recovery process.

[0056] The above ethanol transfer unit (400) connects the boric acid recovery reactor (300) and the ethanol purification reactor (500), and during the boric acid recovery process, the inside of the boric acid recovery reactor (300) is depressurized so that ethanol is depressurized and evaporated, and the ethanol that is depressurized and evaporated in a gaseous state is converted into a liquid state and transferred to the ethanol purification reactor (500).

[0057] The ethanol transfer unit (400) may be configured to include an ethanol transfer pipe (410), an ethanol pressure reduction pump (420), an ethanol cooling unit (430), an ethanol cooling pump (440), and a flow meter (450).

[0058] The above ethanol transfer pipe (410) may be a pipe connecting the boric acid recovery reactor (300) and the ethanol purification reactor (500).

[0059] The above ethanol pressure reduction pump (420) is connected to one side of the ethanol transfer pipe (410) and can be positioned adjacent to the ethanol purification reactor (500), and can reduce the pressure of the internal space of the boric acid recovery reactor (300) by sucking in air through the ethanol transfer pipe (410), and can be equipped with a blower device such as a vacuum pump, a blower, and a fan.

[0060] The above ethanol cooling unit (430) is formed on the outer surface of the ethanol transfer pipe (410) and is formed with a structure in which cooling water flows inside, and may be a cooling device that lowers the temperature of the ethanol transfer pipe (410), and may convert ethanol transferred in a gaseous state along the ethanol transfer pipe (410) into a liquid state.

[0061] The above ethanol cooling pump (440) supplies cooling water at a constant temperature to the ethanol cooling section (430), allowing the cooling water to circulate in the ethanol cooling section (430).

[0062] The above flow meter (450) measures the flow rate of ethanol evaporated from the boric acid recovery reactor (300).

[0063] Based on the measurement results from the flow meter (450), the degree of reaction taking place in the boric acid recovery reactor (300) can be evaluated, and by controlling the degree of opening and closing of the aforementioned demineralized water supply valve (330) in conjunction with the flow meter (450), the decomposition reaction of triethyl borate can be controlled.

[0064] The above ethanol purification reactor (500) can receive ethanol discharged from the boric acid recovery reactor (300), and an ethanol recovery process can be performed to purify and recover the received ethanol.

[0065] Such an ethanol purification reactor (500) may be a reactor that purifies ethanol through a purification process using reduced pressure evaporation or concentrated sulfuric acid, but is not limited thereto.

[0066] In addition, the ethanol purification reactor (500) may be equipped with a purified ethanol tank (510) in addition to the aforementioned internal space.

[0067] The above purified ethanol tank (510) is for storing purified ethanol and is connected to an ethanol purification reactor (500). When the ethanol purification process is completed, the purified ethanol is received from the ethanol purification reactor (500) and stored.

[0068] The exhaust gas treatment unit (600) cools the exhaust gas discharged from the esterification reactor (100), filters particulate radioactive material contained in the cooled exhaust gas, and discharges it to the outside while monitoring the radiation concentration of the filtered exhaust gas.

[0069] Such an exhaust gas treatment unit (600) can be installed by connecting it to the upper part or opening / closing part (120) of the esterification reactor (100) with a screw or clamp.

[0070] Additionally, the exhaust gas treatment unit (600) may be configured to include an exhaust gas cooling unit (610), a high-temperature HEPA filter (620), a radiation monitor (630), and an exhaust gas discharge pump (640).

[0071] The exhaust gas cooling unit (610) cools the exhaust gas containing water and ethanol discharged from the esterification reactor (100) to about 150°C and supplies the cooled exhaust gas to a high-temperature HEPA filter (620).

[0072] The high-temperature HEPA filter (620) filters particulate radioactive material contained in the cooled exhaust gas.

[0073] The radiation monitor (630) measures the radiation concentration of the filtered exhaust gas, and if the radiation concentration exceeds a standard value, it can output a notification or stop the operation of the exhaust gas discharge pump (640).

[0074] The exhaust gas discharge pump (640) above sucks in the exhaust gas of the esterification reactor (100) and allows it to pass sequentially through the exhaust gas cooling unit (610), the high temperature HEPA filter (620), and the radiation monitor (630), and may be equipped with a blower device such as a vacuum pump, a blower, and a fan.

[0075] Meanwhile, in the case of steam generated during the drying process after neutralizing metaboric acid and borates, it may be heated to about 150°C using a separate heating device and then introduced into a high-temperature HEPA filter (620).

[0076] Hereinafter, a method for recovering boric acid from radioactive boric acid waste performed in a boric acid recovery device (10) for radioactive boric acid waste according to one embodiment of the present invention will be described.

[0077]

[0078] FIG. 2 is a diagram of a method for recovering boric acid from radioactive boric acid waste according to the present invention.

[0079] Referring to FIG. 2, the boric acid recovery device (10) for radioactive boric acid waste according to one embodiment of the present invention first supplies hot water to the esterification reactor (100) when radioactive boric acid waste is introduced to perform solution treatment (S110).

[0080] In step S110, the amount of radioactive boric acid waste to be introduced can be determined according to the internal space volume of the esterification reactor (100), and the radioactive boric acid waste can be introduced by opening the opening / closing part (120) of the esterification reactor (100), and the stirring part (130) can be operated from the moment the opening / closing part (120) is closed after introduction to facilitate the solution treatment of the radioactive boric acid waste.

[0081] Meanwhile, if radioactive boric acid waste is introduced as a liquid radioactive boric acid waste solution, the performance of the aforementioned S110 step may be omitted.

[0082] Next, hydrochloric acid is supplied to the radioactive boric acid waste solution in the esterification reactor (100) to induce boric oxidation treatment of metaboric acid and borate compounds and neutralization reaction with Na ions (S120).

[0083] In step S120, the boric acid and borate compounds are boricated by hydrochloric acid introduced into the radioactive boric acid waste solution, and at the same time, a neutralization reaction is carried out to neutralize the bases forming Na ions in the radioactive boric acid waste and convert them into sodium chloride (NaCl).

[0084] Next, the radioactive boric acid waste solution, in which boric oxidation treatment and neutralization reaction are completed in the esterification reactor (100), is dried to form boric acid powder (S130).

[0085] Step S130 can be performed by operating the heating unit (110) of the esterification reactor (100) to heat the internal temperature of the esterification reactor (100) to a specific temperature of 100°C or lower, and at this time, it is preferable to perform the drying treatment at a low temperature to minimize the conversion of the boric acid waste treated with boric acid into metaboric acid or borate.

[0086] Next, ethanol is supplied to boric acid powder in an esterification reactor (100) to induce a boric acid esterification reaction (S210), and when the boric acid esterification reaction reaches equilibrium, a hygroscopic agent is supplied to accelerate the boric acid esterification reaction (S220).

[0087] Step S210 involves supplying ethanol to an esterification reactor (100) containing boric acid powder to bring the boric acid esterification reaction to equilibrium, wherein the amount of ethanol supplied can be 2.5 to 2.6 times greater than the chemical equivalent required for the boric acid esterification reaction.

[0088] Step S210 may supply ethanol stored separately, or it may supply and use purified ethanol stored in the purified ethanol tank (510) by the ethanol purification reactor (500).

[0089] Step S220 can accelerate the boric acid esterification reaction by supplying calcium chloride (CaCl2) as a hygroscopic agent to the esterification reactor (100), thereby minimizing the formation of CaCl2·4C2H5OH and allowing the water produced by the boric acid esterification reaction to be rapidly absorbed.

[0090] Meanwhile, the aforementioned steps S210 and S220 may be performed sequentially or simultaneously.

[0091] In addition, as ethanol and calcium chloride are supplied to the esterification reactor (100), the boric acid and calcium chloride contained in the radioactive boric acid waste are dissolved in ethanol, and the dispersion esterification reaction is continuously carried out in the liquid phase. As a result, more than 80% of the boric acid contained in the radioactive boric acid waste forms triethyl borate, and the calcium chloride reacts with water and ethanol as a hygroscopic agent to produce a mixture of anhydrous calcium chloride and hydrate (CaCl2nH2O) or CaCl2·4C2H5OH, which remains in the esterification reactor (100).

[0092] Next, the reaction product containing triethyl borate and ethanol produced by the boric acid esterification reaction in the esterification reactor (100) is evaporated and discharged (S310), and the reaction residue remaining after the reaction product is discharged is heated and discharged as exhaust gas containing water and ethanol (S320).

[0093] Step S310 can heat the internal space of the esterification reactor (100) to a temperature higher than the evaporation temperature of ethanol and lower than the evaporation temperature of triethyl borate, for example, 100°C to 110°C by operating the heating unit (110) of the esterification reactor (100).

[0094] However, in step S310, the internal space of the esterification reactor (100) can be reduced in pressure by operating the reduced pressure transfer unit (200), so that the triethyl borate can be reduced in pressure evaporated together with ethanol.

[0095] Step S320 can be performed by heating the internal space of the esterification reactor (100) to about 300°C, and the aforementioned reaction residue may include calcium chloride, calcium chloride hydrate and a mixture of CaCl2·4C2H5OH.

[0096] In addition, the exhaust gas discharged in the S320 stage is drawn into the exhaust gas treatment unit (600), cooled to 150°C, and discharged with particulate radioactive material removed in the high-temperature HEPA filter (620).

[0097] In addition, step S320 can recover residual waste, such as a hygroscopic agent, remaining in the esterification reactor (100) after cooling the esterification reactor (100) and recycle it in the next radioactive boric acid waste treatment process.

[0098] The recycling of such absorbents can be repeated until the performance of the absorbent decreases as the amount of residual waste accumulates and boric acid waste treatment becomes impossible, after which it can be recovered and placed in a high-integrity radioactive waste treatment container or solidified using a suitable solidifying agent.

[0099] Next, the reaction product is heated in the boric acid recovery reactor (300) to recover boric acid and discharge ethanol (S410), and the discharged ethanol is purified and recovered in the ethanol purification reactor (500) (S510).

[0100] Step S410 involves recovering ethanol by slowly heating the internal space of the boric acid recovery reactor (300) at a temperature of about 60°C, and once the ethanol recovery is complete, supplying water (deionized water) to the remaining triethyl borate to decompose it into boric acid and ethanol, and then evaporating the ethanol produced during the decomposition process to recover it.

[0101] In addition, step S410 involves, when the ethanol recovery is completely finished, boric acid remains in the internal space of the boric acid recovery reactor (300), where an excess amount of water is introduced to form boric acid water, and the boric acid (boric acid water) can be recovered through the boric acid water outlet (310).

[0102] Step S510 can be performed through a purification process using reduced pressure evaporation or concentrated sulfuric acid in an ethanol purification reactor (500), and once the ethanol purification process is completed, the purified ethanol from the ethanol purification reactor (500) can be stored in a purified ethanol tank (510).

[0103] Although preferred embodiments of the present invention have been described illustratively above, the scope of the present invention is not limited to such specific embodiments and can be appropriately modified within the scope described in the claims.

[0104] It can be used to treat radioactive boric acid waste generated at nuclear power plants.

Claims

1. An esterification reactor in which a boric acid esterification process for removing boric acid contained in radioactive boric acid waste by inducing a boric acid esterification reaction and an evaporation process for evaporating and discharging the reaction product generated by the boric acid esterification reaction are performed sequentially; A boric acid recovery reactor in which a reaction product discharged from the above esterification reactor is received, and a boric acid recovery process is carried out to recover boric acid from the received reaction product and discharge ethanol; and A boric acid recovery device for radioactive boric acid waste comprising: an ethanol purification reactor in which ethanol discharged from the above boric acid recovery reactor is received and an ethanol recovery process is performed to purify and recover the received ethanol.

2. In Paragraph 1, It further includes a pressure reduction transfer unit connecting the esterification reactor and the boric acid recovery reactor, and A boric acid recovery device for radioactive boric acid waste, characterized in that the above-decreased pressure transfer unit reduces the pressure inside the esterification reactor during the evaporation treatment process to cause the reaction product to evaporate under reduced pressure, converts the reaction product evaporated under reduced pressure in a gaseous state into a liquid state, and transfers it to the boric acid recovery reactor.

3. In Paragraph 1, It further includes an ethanol transfer unit connecting the boric acid recovery reactor and the ethanol purification reactor; A boric acid recovery device for radioactive boric acid waste, characterized in that the ethanol transfer unit reduces the pressure inside the boric acid recovery reactor during the boric acid recovery process to cause ethanol to evaporate under reduced pressure, converts the ethanol evaporated under reduced pressure in a gaseous state into a liquid state, and transfers it to the ethanol purification reactor.

4. In Paragraph 1, The system further includes an exhaust gas treatment unit that cools the exhaust gas discharged from the esterification reactor, filters particulate radioactive materials contained in the cooled exhaust gas, and discharges the filtered exhaust gas to the outside while monitoring the radiation concentration of the filtered exhaust gas. A boric acid recovery device for radioactive boric acid waste, characterized in that the above esterification reactor further performs an exhaust process in which, after the evaporation process, the reaction product is discharged and the remaining reaction residue is heated and discharged as exhaust gas containing water and ethanol.

5. A method for recovering boric acid from radioactive boric acid waste performed in a boric acid recovery device for radioactive boric acid waste, wherein (a) A step of supplying hot water to perform solution treatment when radioactive boric acid waste is introduced into an esterification reactor; (b) a step of supplying hydrochloric acid to the radioactive boric acid waste solution in the above esterification reactor to induce boric oxidation treatment of metaboric acid and borate compounds and neutralization reaction with respect to Na ions; (c) A step of drying the radioactive boric acid waste solution, in which the boric oxidation treatment and neutralization reaction are completed in the esterification reactor above, to form boric acid powder; (d) a step of supplying ethanol to boric acid powder in the esterification reactor to induce a boric acid esterification reaction, and supplying a hygroscopic agent to accelerate the boric acid esterification reaction when the boric acid esterification reaction reaches equilibrium; (e) a step of evaporating and discharging the reaction product generated by the boric acid esterification reaction in the esterification reactor, and heating the reaction residue remaining after the reaction product is discharged and discharging it as exhaust gas containing water and ethanol; and (f) a step of heating the reaction product in a boric acid recovery reactor to recover boric acid and discharge ethanol, and purifying and recovering the discharged ethanol in an ethanol purification reactor; comprising a method for recovering boric acid from radioactive boric acid waste.

Images