Nitric acid removal device in high discharge liquid

Abstract

The invention discloses a device for removing nitric acid from high-release liquid. The device for removing nitric acid from high-release liquid includes an extraction evaporation mechanism and a fractionation mechanism, the extraction evaporation mechanism includes an evaporation chamber, a liquid tank, a capillary evaporation component, a circulation component, a condenser, and a liquid tank auxiliary heater, the liquid tank is provided with a liquid inlet and a liquid outlet communicated with its liquid cavity, the capillary evaporation component is arranged in the liquid cavity of the liquid tank, the evaporation chamber is connected to the liquid tank, and the evaporation cavity of the evaporation chamber is communicated with the liquid cavity of the liquid tank, the liquid tank auxiliary heater is connected to the liquid tank, the circulation component, the evaporation chamber, and the condenser are connected in series in sequence; the fractionation mechanism includes a fractionation tower, an electrolytic cell, and a rectifying tower, the fractionation tower is connected to the condenser, and the fractionation tower, the electrolytic cell, and the rectifying tower are connected in series in sequence. The device for removing nitric acid from high-release liquid can effectively remove nitric acid from high-release liquid, does not introduce new reagents into the liquid, does not pollute the liquid, and does not increase additional radioactive waste emissions.

Description

Technical Field

[0001] The invention relates to the field of chemical industry, in particular to a device for removing nitric acid from high-discharge liquid. Background Art

[0002] In the field of nuclear fuel reprocessing, high-release liquid is often stored in a concentrated manner, resulting in a high acidity of the high-release liquid. During reprocessing, the acidity needs to be reduced due to the requirements of the process treatment technology. Among the traditional methods of reducing acidity, one is to add chemical reagents to react and remove acid, such as adding alkali to the high-release liquid to reduce the acidity of the high-release liquid through acid-base neutralization reaction, but this will increase the salt content of the liquid, increase the difficulty of the reprocessing process and the amount of final waste disposal. Another method is to add non-salting reagents such as formaldehyde or formic acid to the high-release liquid, and reduce nitric acid through a microwave chemical process to generate water, nitrogen oxides and carbon dioxide. This treatment method will not increase the salt content of the liquid, but chemical reagents are still added to the liquid. The final products of these chemical reagents need to be treated or disposed of in the form of radioactive waste, which increases additional radioactive waste emissions. Summary of the invention

[0003] Based on this, it is necessary to provide a device for removing nitric acid from high discharge liquid. The device for removing nitric acid from high discharge liquid of the present invention can effectively remove nitric acid from high discharge liquid without introducing new reagents into the liquid, polluting the liquid, or increasing additional radioactive waste discharge.

[0004] A device for removing nitric acid from high-discharge liquid, comprising:

[0005] An extraction evaporation mechanism, the extraction evaporation mechanism comprising an evaporation chamber, a liquid tank, a capillary evaporation component, a circulation component, a condenser and a liquid tank auxiliary heater, the liquid tank is provided with a liquid inlet and a liquid outlet communicated with its liquid cavity, the capillary evaporation component is arranged in the liquid cavity of the liquid tank, the evaporation chamber is connected to the liquid tank and the evaporation cavity of the evaporation chamber is communicated with the liquid cavity of the liquid tank, the liquid tank auxiliary heater is connected to the liquid tank for auxiliary heating of the liquid tank, the circulation component, the evaporation chamber, and the condenser are connected in series in sequence; and

[0006] A fractionation mechanism, the fractionation mechanism comprises a fractionation tower, an electrolytic cell and a rectification tower, the fractionation tower is connected to the condenser, and the fractionation tower, the electrolytic cell and the rectification tower are connected in series in sequence.

[0007] In some embodiments, the capillary evaporation component includes a capillary mesh, one side of the capillary evaporation component is located in the liquid chamber of the liquid tank, and the other side thereof extends into the evaporation chamber of the evaporation chamber.

[0008] In some embodiments, the capillary evaporation component includes a plurality of the capillary meshes, and the plurality of the capillary meshes are stacked and have gaps between adjacent capillary meshes.

[0009] In some of the embodiments, the extraction evaporation mechanism further includes a liquid tank auxiliary heater, and the liquid tank auxiliary heater is connected to the liquid tank for auxiliary heating of the liquid tank.

[0010] In some of the embodiments, the fractionation mechanism further comprises a concentrated nitric acid tank, which is connected to the distillation tower for collecting concentrated nitric acid from the distillation tower.

[0011] In some embodiments, the fractionation mechanism further includes a hydrogen-oxygen combustion chamber, which is connected to the electrolytic cell and is used to collect hydrogen and oxygen from the electrolytic cell and perform a combustion reaction.

[0012] In some embodiments, the hydrogen-oxygen combustion chamber is also connected to the fractionation tower, and the water generated in the hydrogen-oxygen combustion chamber flows back into the fractionation tower.

[0013] In some embodiments, the hydrogen-oxygen combustion chamber contains a condenser;

[0014] And / or, the hydrogen-oxygen combustion chamber contains an air buffer tank;

[0015] And / or, an electric spark igniter is installed in the hydrogen-oxygen combustion chamber.

[0016] In some of the embodiments, the circulation component is a centrifugal fan, and a pressure reducing valve is installed on the circulation component.

[0017] In some embodiments, the rectification tower is further connected to the fractionation tower via a gas phase outlet at the top thereof.

[0018] In some embodiments, the fractionation tower is connected to the circulation component via a gas phase outlet at the top thereof.

[0019] In some of the embodiments, the liquid tank auxiliary heater is a steam heater and / or an electric heater.

[0020] In some embodiments, the electrolytic cell is an electrolytic electrodialysis cell.

[0021] In some embodiments, the number of the extraction and evaporation mechanisms is several, and the plurality of the extraction and evaporation mechanisms are connected in series or in parallel to the fractionation mechanism.

[0022] The above-mentioned nitric acid removal device in high-release liquid can effectively remove nitric acid in high-release liquid, without introducing new reagents into the liquid, without polluting the liquid, and without increasing the emission of additional radioactive waste. The nitric acid removal device in high-release liquid of the present invention removes acid by a purely physical method, does not pollute the liquid, and the acid removal process is gentle, does not cause changes in the reagent composition of the liquid, and minimizes the emission of radioactive waste; there are no moving parts in the high-release area, which is conducive to equipment maintenance; the use method is flexible, and the extraction evaporation mechanism can be used as a batch device or a continuous device, can be used in parallel or in series, and multiple can share one fractionation mechanism. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present application, and those skilled in the art can obtain other drawings based on these drawings without creative work.

[0024] In order to more completely understand the present application and its beneficial effects, the following description will be given in conjunction with the accompanying drawings. In the following description, the same reference numerals represent the same parts.

[0025] Figure 1 It is a schematic diagram of a device for removing nitric acid from high-discharge liquid according to one embodiment of the present invention.

[0026] Description of Reference Numerals

[0027] 10. Device for removing nitric acid from high-release liquid; 100. evaporation chamber; 200. liquid tank; 200a. auxiliary heater for liquid tank; 300. capillary evaporation assembly; 400. circulation assembly; 500. condenser; 600. fractionation tower; 700. electrolytic cell; 800. distillation tower; 900. concentrated nitric acid tank; 1000. hydrogen-oxygen combustion chamber; 1101. first pipeline; 1102. second pipeline; 1103. third pipeline; 1104. fourth pipeline; 1105. fifth pipeline; 1106. sixth pipeline; 1107. seventh pipeline; 1108. eighth pipeline; 1109. ninth pipeline; 1110. oxygen pipeline; 1111. hydrogen pipeline. DETAILED DESCRIPTION

[0028] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific embodiments of the present invention are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present invention, so the present invention is not limited by the specific embodiments disclosed below.

[0029] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0030] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0031] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0032] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0033] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it may be directly on the other element or there may be a central element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. The terms "vertical", "horizontal", "upper", "lower", "left", "right" and similar expressions used herein are for illustrative purposes only and are not intended to be the only implementation method.

[0034] In the description of the present invention, "several" means more than one, "many" means more than two, "greater than", "less than", "exceed", etc. are understood to exclude the number itself, and "above", "below", "within", etc. are understood to include the number itself. If there is a description of "first" or "second", it is only used for the purpose of distinguishing the technical features, and cannot be understood as indicating or implying the relative importance or implicitly indicating the number of the indicated technical features or implicitly indicating the order of the indicated technical features.

[0035] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those generally understood by those skilled in the art of the present invention. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more related listed items.

[0036] The embodiment of the present application provides a device 10 for removing nitric acid from high-discharge liquid to solve the problem that the conventional method for reducing acidity leads to increased salinity in the liquid, increased difficulty in the post-processing process and the amount of final waste disposal, and increased additional radioactive waste discharge. The following will be described in conjunction with the accompanying drawings.

[0037] The device 10 for removing nitric acid from high-discharge liquid provided in the embodiment of the present application is exemplary, see Figure 1 As shown, Figure 1 The schematic diagram of the structure of the device 10 for removing nitric acid from high-discharge liquid provided in the embodiment of the present application is as follows. The device 10 for removing nitric acid from high-discharge liquid of the present application can be used for removing nitric acid from high-discharge liquid.

[0038] In order to more clearly illustrate the structure of the device for removing nitric acid from high-pressure liquid 10, the device for removing nitric acid from high-pressure liquid 10 will be introduced below with reference to the accompanying drawings.

[0039] For example, see Figure 1 As shown, a device 10 for removing nitric acid from high-discharge liquid includes an extraction evaporation mechanism and a fractionation mechanism.

[0040] The extraction evaporation mechanism includes an evaporation chamber 100, a liquid tank 200, a capillary evaporation component 300, a circulation component 400 and a condenser 500. The liquid tank 200 is provided with a liquid inlet and a liquid outlet communicated with its liquid cavity. The capillary evaporation component 300 is arranged in the liquid cavity of the liquid tank 200. The evaporation chamber 100 is connected to the liquid tank 200 and the evaporation cavity of the evaporation chamber 100 is communicated with the liquid cavity of the liquid tank 200. The circulation component 400, the evaporation chamber 100 and the condenser 500 are connected in series in sequence.

[0041] The fractionation mechanism includes a fractionation tower 600, an electrolytic cell 700 and a rectification tower 800. The fractionation tower 600 is connected to the condenser 500, and the fractionation tower 600, the electrolytic cell 700 and the rectification tower 800 are sequentially connected in series.

[0042] In the above-mentioned device 10 for removing nitric acid from high-release liquid, in the evaporation chamber 100, the circulation component 400 inhales saturated water vapor and blows it toward the capillary evaporation component 300 in the evaporation chamber 100. The liquid in the liquid tank 200 is adsorbed onto the capillary evaporation component 300 due to capillary action and evaporates under the action of the saturated water vapor blown in. Since the partial pressure of nitric acid vapor in the saturated water vapor is close to zero, and the partial pressure of water vapor is in a saturated state, the water content of the liquid cannot evaporate, but the nitric acid will evaporate, thereby achieving the purpose of reducing the acidity in the liquid.

[0043] In some embodiments, the evaporation chamber 100, the liquid tank 200 and the condenser 500 can be made of stainless steel. The fractionation tower 600 and the rectification tower 800 are customized glass-filled rectification columns. The electrolytic cell 700 is a purchased sealed quartz H-type replaceable ion membrane electrolytic cell 700.

[0044] In some embodiments, the extraction evaporation mechanism further includes a liquid tank auxiliary heater 200a. The liquid tank auxiliary heater 200a is connected to the liquid tank 200 to assist in heating the liquid tank 200. The liquid tank auxiliary heater 200a appropriately heats the liquid, increases the liquid volatilization rate, replenishes the heat taken away by the liquid evaporation, accelerates the liquid convection diffusion, and avoids local scaling of the capillary evaporation component 300. Figure 1 As shown, the liquid tank auxiliary heater 200a is connected to the bottom of the liquid tank 200.

[0045] In some of the embodiments, the liquid inlet on the liquid tank 200 is located at the upper part of the liquid tank 200 , and the liquid outlet on the liquid tank 200 is located at the lower part of the liquid tank 200 .

[0046] In some embodiments, the extraction evaporation mechanism further includes a first pipe 1101, a second pipe 1102, and a third pipe 1103. Specifically, one end of the first pipe 1101 is connected to the inlet of the evaporation chamber 100, and the other end of the first pipe 1101 is connected to the outlet of the circulation component 400. One end of the second pipe 1102 is connected to the outlet of the evaporation chamber 100, and the other end of the second pipe 1102 is connected to the inlet of the condenser 500. One end of the third pipe 1103 is connected to the outlet of the condenser 500, and the other end of the third pipe 1103 is connected to the first liquid inlet of the fractionation tower 600, wherein the first liquid inlet of the fractionation tower 600 is located at its lower position.

[0047] In some embodiments, the capillary evaporation component 300 includes a capillary mesh. One side of the capillary evaporation component 300 is located in the liquid chamber of the liquid tank 200 , and the other side thereof extends into the evaporation chamber of the evaporation chamber 100 .

[0048] In some embodiments, the capillary mesh may be a stainless steel sintered mesh made of stainless steel. In the present invention, the capillary mesh is a stainless steel sintered mesh, which is conducive to capillary action and can effectively absorb the feed liquid from the feed liquid tank 200.

[0049] In some embodiments, the capillary evaporation component 300 includes a plurality of capillary meshes. The plurality of capillary meshes are stacked and arranged with gaps between adjacent capillary meshes. The plane where the frame of each layer of the capillary mesh is located is aligned with the flow direction of the gas in the evaporation chamber 100 (refer to Figure 1 The capillary evaporation component 300 is a multi-layer capillary mesh stacking structure, which increases the evaporation area. The plane of each capillary mesh layer is parallel to the flow direction of the gas in the evaporation chamber 100. The gaps between adjacent capillary mesh layers are conducive to the passage of gas, reducing the gas flow resistance.

[0050] Because the radioactive liquid contains 14 C. 3 H. 18 O and other radioactive nuclides diffuse into all liquids due to isotope exchange during the liquid treatment process, and it is not economical to separate these nuclides isotopically. Therefore, the newly added elements such as C, H, and O for the treatment of nitric acid can only be treated as radioactive waste. Therefore, the treatment process should minimize the introduction of elements, that is, consider the atomic economy of the treatment of nitric acid.

[0051] Taking the atom economy of formaldehyde deacidification as the comparison object, the chemical reaction equation is:

[0052] HCHO+4HNO3=CO2↑+4NO2↑+3H2O;

[0053] Atom economy is that to process 1 mol of nitric acid, an additional 0.5 mol of hydrogen atoms, 0.25 mol of oxygen atoms and 0.25 mol of carbon atoms are required.

[0054] For some of these examples, see Figure 1 As shown, the fractionation mechanism also includes a concentrated nitric acid tank 900. The concentrated nitric acid tank 900 can be customized with stainless steel. The concentrated nitric acid tank 900 is connected to the distillation tower 800 to collect concentrated nitric acid from the distillation tower 800. The concentrated nitric acid in the concentrated nitric acid tank 900 can be used as a product for the spent fuel dissolution process at the head end of the post-processing, and has good atomic economy. If the concentrated nitric acid in the concentrated nitric acid tank 900 is treated as waste, it can be reduced with carbon powder, and its chemical reaction formula is:

[0055] C+4HNO3=CO2↑+4NO2↑+2H2O;

[0056] The atomic economy of the whole process in the concentrated nitric acid tank 900 is: to treat 1 mol of nitric acid, 0.142 mol of hydrogen atoms, 0.071 mol of oxygen atoms and 0.25 mol of carbon atoms need to be additionally introduced. Compared with formaldehyde denitration, the present invention has good atomic economy.

[0057] For some of these examples, see Figure 1 As shown, the fractionation mechanism further includes a hydrogen-oxygen combustion chamber 1000. The hydrogen-oxygen combustion chamber 1000 is connected to the electrolytic cell 700, and is used to collect hydrogen and oxygen from the electrolytic cell 700 and perform a combustion reaction. The hydrogen-oxygen combustion chamber 1000 can be customized with stainless steel.

[0058] For some of these examples, see Figure 1 As shown, the hydrogen-oxygen combustion chamber 1000 is also connected to the fractionation tower 600. The water generated in the hydrogen-oxygen combustion chamber 1000 flows back into the fractionation tower 600.

[0059] In some of the embodiments, the circulation component 400 is a centrifugal fan. A pressure reducing valve is installed on the circulation component 400. One advantage of the circulation component 400 using a centrifugal fan is that the air volume and air pressure of the centrifugal fan are relatively large, and the air volume and air pressure can be conveniently adjusted in conjunction with the pressure reducing valve, and the pressure of the outlet water vapor can be adjusted so that it is in a saturated state and condenses as little as possible. Another advantage of the centrifugal fan is that it is easy to seal, which is beneficial for the fractionation mechanism to maintain negative pressure operation. For example, in one of the specific examples, the centrifugal fan is a small outer rotor stainless steel fan.

[0060] For some of these examples, see Figure 1 As shown, the rectification tower 800 is also connected to the fractionation tower 600 via a gas phase outlet at the top thereof.

[0061] For some of these examples, see Figure 1 As shown, the fractionation tower 600 is connected to the circulation component 400 via a gas phase outlet at the top thereof.

[0062] In some embodiments, the liquid tank auxiliary heater 200a is a steam heater and / or an electric heater. The use of a steam heater or an electric heater can improve the radiation resistance and is easy to adjust.

[0063] In some embodiments, the electrolytic cell 700 is an electrolytic electrodialysis cell. The electrolytic cell 700 is an electrolytic electrodialysis cell, which can enrich hydrogen ions and hydroxide ions in concentrated nitric acid to the vicinity of electrodes through the electrodialysis process, thereby improving electrolysis efficiency.

[0064] In some embodiments, the oxyhydrogen combustion chamber 1000 includes a condenser 500. The oxyhydrogen combustion chamber 1000 includes a condenser 500 to enable water to flow back in liquid form, thereby separating from the gas in the oxyhydrogen combustion chamber 1000, thereby achieving the purpose of preventing the gas in the oxyhydrogen combustion chamber 1000 from leaking.

[0065] In some embodiments, the hydrogen-oxygen combustion chamber 1000 includes an air buffer tank. The hydrogen-oxygen combustion chamber 1000 includes an air buffer tank, which can ensure that the hydrogen combustion in the combustion chamber is always in an oxygen excess state, so that the hydrogen combustion is sufficient and complete. Since the hydrogen-oxygen combustion is a fixed chemical ratio, and hydrogen and oxygen are also fed in accordance with the chemical ratio of the hydrogen-oxygen combustion, the total amount of oxygen in the air buffer tank will not be reduced due to chemical reactions, and since the gas in the hydrogen-oxygen combustion chamber 1000 will not leak, the air in the hydrogen-oxygen combustion chamber 1000 does not need to be supplemented.

[0066] In some embodiments, an electric spark igniter is installed in the hydrogen-oxygen combustion chamber 1000. The electric spark igniter is simple, reliable and easy to operate.

[0067] For some of these examples, see Figure 1 As shown, the fractionation mechanism further includes a fourth pipeline 1104 , a fifth pipeline 1105 , a sixth pipeline 1106 , a seventh pipeline 1107 , an eighth pipeline 1108 , a ninth pipeline 1109 , an oxygen pipeline 1110 and a hydrogen pipeline 1111 .

[0068] Specifically, one end of the fourth pipeline 1104 is connected to the liquid phase outlet of the fractionation tower 600, and the other end is connected to the acid liquid inlet of the electrolytic cell 700, wherein the liquid phase outlet of the fractionation tower 600 is located at its lower position. One end of the fifth pipeline 1105 is connected to the acid liquid outlet of the electrolytic cell 700, and the other end is connected to the liquid phase inlet of the distillation tower 800, wherein the liquid phase inlet of the distillation tower 800 is located at its lower position. One end of the sixth pipeline 1106 is connected to the liquid phase outlet of the distillation tower 800, and the other end is connected to the inlet of the concentrated nitric acid tank 900, wherein the liquid phase outlet of the distillation tower 800 is located at its lower position. One end of the seventh pipeline 1107 is connected to the water collection outlet of the hydrogen-oxygen combustion chamber 1000, and the other end is connected to the second liquid inlet of the fractionation tower 600, wherein the second liquid inlet of the fractionation tower 600 is located at its lower position. One end of the eighth pipeline 1108 is connected to the gas phase outlet at the top of the rectifying tower 800, and the other end is connected to the third liquid inlet of the fractionating tower 600, wherein the third liquid inlet of the fractionating tower 600 is located at its lower position. One end of the ninth pipeline 1109 is connected to the gas phase outlet at the top of the fractionating tower 600, and the other end is connected to the inlet of the circulation component 400. One end of the oxygen pipeline 1110 is connected to the electrolytic cell 700, and the other end is connected to the oxygen inlet of the hydrogen-oxygen combustion chamber 1000. One end of the hydrogen pipeline 1111 is connected to the electrolytic cell 700, and the other end is connected to the hydrogen inlet of the hydrogen-oxygen combustion chamber 1000.

[0069] In some of the embodiments, the number of extraction evaporation mechanisms is several. Multiple extraction evaporation mechanisms are connected in series, or in parallel to the fractionation mechanism. The extraction evaporation mechanisms can be connected in parallel to expand the nitric acid processing capacity, or they can be connected in series to gradually reduce the acidity of the feed liquid and improve the total mass transfer driving force for acid removal. Since the connection relationship (pipeline, interface) between the extraction evaporation mechanism and the fractionation mechanism is clear, there are only two logistics, that is, the fractionation mechanism transports water vapor to the extraction evaporation mechanism and the extraction evaporation mechanism transports dilute nitric acid to the fractionation mechanism, without excessive logistics coupling. Therefore, the two units of the extraction evaporation mechanism and the fractionation mechanism can be modularly divided, and the extraction evaporation mechanism and the fractionation mechanism can be composed of a device with a quantity ratio of 1:1, or a plurality of extraction evaporation mechanisms can be connected to one fractionation mechanism.

[0070] When the above-mentioned high-release nitric acid removal device 10 is installed, the components in the high-release environment are the evaporation chamber 100, the capillary evaporation component 300, the liquid tank 200, the liquid tank auxiliary heater 200a and the corresponding pipelines, and the above-mentioned components are all immovable components. The circulation component 400, the fractionation tower 600, the rectification tower 800 and the concentrated nitric acid tank 900 are all in a low-release environment. The above-mentioned high-release nitric acid removal device 10 has high installation reliability, is easy to maintain, and has high safety in use.

[0071] The working principle of the nitric acid removal device 10 in the high-release liquid is as follows: the distillation mechanism distills the dilute nitric acid into concentrated nitric acid and water vapor. The distillation mechanism works in a low-release environment, and the operation process is a conventional process, but it should be noted that since nitric acid and water can form an azeotrope, simple distillation cannot increase the nitric acid concentration to more than 68%. If the concentration in the concentrated nitric acid tank 900 is only concentrated to 68%, it is not conducive to minimizing radioactive waste. Therefore, it is necessary to increase the concentration of concentrated nitric acid and further concentrate the nitric acid concentration to more than 95%. The present invention uses an electrolytic cell 700 to electrolyze water in nitric acid, so that the nitric acid aqueous solution is separated from the azeotropic composition, and then distills to obtain concentrated nitric acid and water. The electrolysis method does not introduce new atoms and has the best atomic economy. The hydrogen and oxygen after electrolysis are burned into water in the combustion chamber and then refluxed to the distillation tower 600, so that the radioactive isotopes of hydrogen and oxygen operate in a closed loop. When the concentration of concentrated nitric acid waste liquid in the concentrated nitric acid tank 900 reaches 98%, the ratio of the amount of water and nitric acid is about 0.071:1, that is, relative to the treatment of 1 mol of nitric acid, it is necessary to additionally introduce 0.071 mol of water, that is, 0.142 mol of hydrogen atoms and 0.071 mol of oxygen atoms. Compared with formaldehyde denitrification, it has good atomic economy and achieves the minimization of radioactive waste.

[0072] When the above-mentioned nitric acid removal device 10 in high-release liquid is in use, the extraction evaporation mechanism can be used as a batch device. Specifically, the high-release liquid flows into the liquid inlet of the liquid tank 200 and is sealed, and then evaporated until the liquid is qualified, and then the extraction evaporation mechanism is closed, and the liquid outlet of the liquid tank 200 is opened to discharge the liquid to the designated device. It should be noted that when the extraction evaporation mechanism is used as a batch device for a single time, the capillary net of the capillary evaporation component 300 needs to be washed multiple times after the liquid tank 200 is discharged and the washing liquid is combined to eliminate the influence of the residual liquid in the capillary net. When the extraction evaporation mechanism is used multiple times as a batch device, due to the subsequent cleaning and merging of the liquid, additional washing is not required. The extraction evaporation mechanism can also be used as a continuous device: the liquid flows continuously from the liquid inlet of the liquid tank 200, evaporates continuously in the extraction evaporation unit, and flows continuously out from the liquid outlet of the liquid tank 200 to the designated device.

[0073] For example, in one of the specific examples, the specific operation steps of the above-mentioned high-level radioactive waste liquid removal device 10 are as follows: 20L of power reactor high-level radioactive waste liquid simulation liquid flows into the liquid inlet of the liquid tank 200, and the acidity of the high-level radioactive waste liquid simulation liquid is 3mol / L nitric acid, the liquid inlet of the liquid tank 200 is closed, and the extraction and evaporation mechanism is sealed; the circulation component 400, the condenser 500 and the fractionation mechanism are started, and the liquid tank auxiliary heater 200a heats the liquid in the liquid tank 200 to 45°C and keeps it warm, and the temperature of the condenser 500 is maintained at 10°C, and the liquid is extracted and evaporated; after 5 hours, the circulation component 400, the condenser 500, the liquid tank auxiliary heater 200a and the fractionation mechanism are stopped. The extraction and evaporation mechanism is a batch device for single operation and needs to be washed. The concentration of nitric acid in the liquid tank 200 is detected, and the liquid in the liquid tank 200 flows out to the distillation kettle of the fractionation tower 600. The distillation kettle distills the liquid flowing out, and the dilute nitric acid vapor distilled out is condensed and rinses the liquid tank 200 and the capillary mesh of the capillary evaporation component 300. The rinse liquid flows out and merges into the bottom liquid of the distillation kettle. The distillation, rinsing and merging are repeated five times, and the composition of the final liquid in the distillation kettle is weighed and analyzed; the final acidity of the liquid is 1.1 mol / L nitric acid, and except for nitric acid, the quality of other components in the liquid does not suffer obvious loss. It can be seen that the nitric acid removal device 10 in the high-release liquid of the present invention can effectively remove nitric acid in the high-release liquid.

[0074] The above-mentioned nitric acid removal device 10 in high-release liquid can effectively remove nitric acid in high-release liquid, without introducing new reagents into the liquid, without polluting the liquid, and without increasing the emission of additional radioactive waste. The nitric acid removal device 10 in high-release liquid of the present invention is a purely physical method for acid removal, does not pollute the liquid, and the acid removal process is gentle, does not cause changes in the reagent composition of the liquid, and minimizes the emission of radioactive waste; there are no moving parts in the high-release area, which is conducive to equipment maintenance; the use method is flexible, and the extraction evaporation mechanism can be used as a batch device or a continuous device, can be used in parallel or in series, and multiple can share one fractionation mechanism.

[0075] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0076] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0077] The above-mentioned embodiments only express several implementation methods of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the scope of the patent of the present invention. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A device for removing nitric acid from high discharge liquid, characterized in that: include: An extraction evaporation mechanism, the extraction evaporation mechanism comprising an evaporation chamber, a liquid tank, a capillary evaporation component, a circulation component and a condenser, the liquid tank being provided with a liquid inlet and a liquid outlet communicating with its liquid cavity, the capillary evaporation component being arranged in the liquid cavity of the liquid tank, the evaporation chamber being connected to the liquid tank and the evaporation cavity of the evaporation chamber being communicated with the liquid cavity of the liquid tank, the circulation component, the evaporation chamber and the condenser being connected in series in sequence; and A fractionation mechanism, the fractionation mechanism comprises a fractionation tower, an electrolytic cell and a rectification tower, the fractionation tower is connected to the condenser, and the fractionation tower, the electrolytic cell and the rectification tower are connected in series in sequence.

2. The device for removing nitric acid from high discharge liquid according to claim 1, characterized in that: The capillary evaporation component comprises a capillary net, one side of the capillary evaporation component is located in the liquid cavity of the liquid tank, and the other side thereof extends into the evaporation cavity of the evaporation chamber.

3. The device for removing nitric acid from high discharge liquid according to claim 2, characterized in that: The capillary evaporation component comprises a plurality of capillary nets, and the plurality of capillary nets are stacked and arranged with gaps between adjacent capillary nets.

4. The device for removing nitric acid from high discharge liquid according to any one of claims 1 to 3, characterized in that: The extraction evaporation mechanism further includes a liquid tank auxiliary heater, which is connected to the liquid tank for auxiliary heating of the liquid tank.

5. The device for removing nitric acid from high discharge liquid according to any one of claims 1 to 3, characterized in that: The fractionation mechanism further comprises a concentrated nitric acid tank, which is connected to the distillation tower for collecting concentrated nitric acid from the distillation tower.

6. The device for removing nitric acid from high discharge liquid according to any one of claims 1 to 3, characterized in that: The fractionation mechanism further includes a hydrogen-oxygen combustion chamber, which is connected to the electrolytic cell and is used to collect hydrogen and oxygen from the electrolytic cell and perform a combustion reaction.

7. The device for removing nitric acid from high discharge liquid according to claim 6, characterized in that: The hydrogen-oxygen combustion chamber is also connected to the fractionation tower, and the water generated in the hydrogen-oxygen combustion chamber flows back into the fractionation tower.

8. The device for removing nitric acid from high discharge liquid according to claim 6, characterized in that: The hydrogen-oxygen combustion chamber contains a condenser; And / or, the hydrogen-oxygen combustion chamber contains an air buffer tank; And / or, an electric spark igniter is installed in the hydrogen-oxygen combustion chamber.

9. The device for removing nitric acid from high discharge liquid according to any one of claims 1-3, 7-8, characterized in that: The circulation component is a centrifugal fan, and a pressure reducing valve is installed on the circulation component.

10. The device for removing nitric acid from high discharge liquid according to any one of claims 1-3, 7-8, characterized in that: The rectifying tower is also connected to the fractionating tower via a gas phase outlet at the top thereof.

11. The device for removing nitric acid from high discharge liquid according to any one of claims 1-3, 7-8, characterized in that: The fractionating tower is connected to the circulation component via a gas phase outlet at the top thereof.

12. The device for removing nitric acid from high discharge liquid according to claim 4, characterized in that: The auxiliary heater of the liquid tank is a steam heater and / or an electric heater.

13. The device for removing nitric acid from high discharge liquid according to any one of claims 1-3, 7-8, characterized in that: The electrolytic cell is an electrolytic electrodialysis cell.

14. The device for removing nitric acid from high discharge liquid according to any one of claims 1-3, 7-8, characterized in that: The number of the extraction and evaporation mechanisms is several, and the plurality of extraction and evaporation mechanisms are connected in series or in parallel to the fractionation mechanism.

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