An apparatus and method for preparing dissolved oxygen and dissolved hydrogen by electro-deionization.

Abstract

This invention discloses an apparatus and method for preparing dissolved oxygen and dissolved hydrogen by electrodeionization, comprising an adjustable power supply, a HO-EDI component, a first EDI component, and a second EDI component; the first outlet of the HO-EDI component is connected to the inlet of the first EDI component, the second outlet of the HO-EDI component is connected to the inlet of the second EDI component, and the adjustable power supply is connected to the HO-EDI component. This apparatus and method can produce dissolved oxygen and dissolved hydrogen, and the amount of oxygen and hydrogen added is adjustable.

Description

Technical Field

[0001] This invention belongs to the field of gas preparation and relates to an apparatus and method for preparing dissolved oxygen and dissolved hydrogen by electrodeionization. Background Technology

[0002] Power plant thermal systems often use dissolved oxygen and dissolved hydrogen to control the working fluid to meet relevant water and steam quality standards. Thermal power plants frequently use oxygenated treatment (OT) to treat feedwater and inhibit metal corrosion. This involves using a certain concentration of oxygen in pure water to form a protective film of Fe2O3 + magnetic Fe3O4 on the carbon steel surface, which offers better protection than magnetic Fe3O4. Under oxygenated feedwater conditions, the carbon steel surface film has a double-layer structure. Furthermore, the solubility of Fe2O3 is much lower than that of Fe3O4, resulting in a denser and more stable protective film that can withstand accelerated corrosion from flowing water, thereby reducing the iron concentration in the feedwater. Oxygenation is typically achieved by adding oxygen, air, or water containing oxygen.

[0003] Pressurized water reactor (VVER) nuclear power plants typically add ammonia to the primary coolant. The ammonia decomposes under irradiation to produce hydrogen, and maintaining the ammonia concentration ensures a stable dissolved hydrogen concentration in the coolant. Therefore, VVER units do not have a hydrogen addition system. During normal operation, the ammonia concentration is required to be greater than or equal to 3 mg / L. In actual control, the ammonia concentration generally does not exceed 20 mg / L, and the concentration at full power is approximately 3-10 mg / L. When operating at or above 40% of rated power, the ammonia concentration must be adjusted to ensure the dissolved hydrogen concentration is within the range of 2.2-4.5 mg / L. Controlling the lower limit of dissolved hydrogen concentration is to inhibit water decomposition under irradiation and control the dissolved oxygen concentration; while controlling the upper limit is to prevent hydrogen embrittlement caused by excessive hydrogen concentration potentially leading to hydrogen absorption by the zirconium cladding. Additionally, ammonia in the primary coolant has a certain buffering effect on pH, which is beneficial for pH stability. Especially during reactor cooling, because ammonia has a high degree of ionization at low temperatures, it can maintain the coolant's pH with good buffering performance, keeping the water quality within a reasonable pH range and reducing the corrosion rate of materials. The drawback of this water chemistry process is that water quality control and adjustment are relatively difficult, and the ammonia addition operation and ammonia control must be strictly controlled. The ammonia-potassium saturation of the resin in the coolant purification system is in dynamic equilibrium. During ammonia-potassium saturation and water quality adjustment, excessively high ammonia concentrations or too rapid ammonia addition can easily wash away corrosive ions such as chloride ions from the resin, causing water quality deterioration or even exceeding standards. The ammonia and potassium concentrations in the coolant influence each other, making it difficult to adjust hydrogen and potassium concentrations. Changes in hydrogen concentration lag behind ammonia concentrations, and the time when changes in ammonia in the purification system resin cause potassium release usually lags by more than 8 hours. Careless operation can easily lead to deviations in water quality.

[0004] It is evident that the devices used to achieve the aforementioned oxygen or hydrogen addition are typically quite complex and pose certain safety hazards. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the prior art and provide an apparatus and method for preparing dissolved oxygen and dissolved hydrogen by electrodeionization. The apparatus and method are capable of producing dissolved oxygen and dissolved hydrogen, and the amount of oxygen and hydrogen added is adjustable.

[0006] To achieve the above objectives, the apparatus for preparing dissolved oxygen and dissolved hydrogen by electro-deionization according to the present invention includes an adjustable power supply, an HO-EDI component, a first EDI component, and a second EDI component.

[0007] The first outlet of the HO-EDI component is connected to the inlet of the first EDI component, the second outlet of the HO-EDI component is connected to the inlet of the second EDI component, and the adjustable power supply is connected to the HO-EDI component.

[0008] A further improvement of the apparatus for preparing dissolved oxygen and dissolved hydrogen by electro-deionization according to the present invention is as follows:

[0009] Furthermore, the HO-EDI component includes an anode, a cation exchange membrane, an anion exchange membrane, and a cathode arranged sequentially. An adjustable power supply is connected to the anode and the cathode. An O cavity is formed between the anode and the cation exchange membrane, an M cavity is formed between the cation exchange membrane and the anion exchange membrane, and an H cavity is formed between the anion exchange membrane and the cathode. A first water inlet pipe is connected to the first EDI component via the O cavity, and a second water inlet pipe is connected to the second EDI component via the H cavity.

[0010] Furthermore, the O cavity is filled with cation exchange resin.

[0011] Furthermore, the M cavity is filled with a mixed ion exchange resin.

[0012] Furthermore, the H cavity is filled with anion exchange resin.

[0013] Furthermore, pure water containing alkaline substances is sequentially passed through the O chamber and the first EDI component to generate oxygenated pure water.

[0014] Furthermore, pure water containing alkaline substances is sequentially passed through the H-chamber and the second EDI component to generate hydrogen-containing pure water.

[0015] Furthermore, the alkaline substance is NaOH, KOH, or NH4OH.

[0016] Furthermore, by adjusting the current of the adjustable power supply, the oxygen concentration in the oxygen-containing purified water and the hydrogen concentration in the hydrogen-containing purified water can be adjusted.

[0017] The method for preparing dissolved oxygen and dissolved hydrogen by electro-deionization according to the present invention includes the following steps:

[0018] Pure water with added alkaline substances enters chamber 0 and chamber H respectively. In chamber O, the alkaline water undergoes an oxygen evolution reaction, and most of the original cations in the water pass through the cation exchange membrane into chamber M. The generated oxygen and the remaining anions and cations flow into the first EDI component. In the first EDI component, the remaining anions and cations are further removed, so that the effluent contains only oxygen.

[0019] The alkaline water in the H cavity undergoes electrolysis. Hydrogen ions gain electrons at the cathode and undergo hydrogen evolution. The OH- produced by water electrolysis... - Most of the water passes through the anion exchange membrane and enters the M chamber. The generated hydrogen gas and the remaining anions and cations flow into the second EDI module with the water flow. In the second EDI module, the remaining anions and cations are further removed, and the effluent contains only hydrogen gas.

[0020] In the M cavity, cations from the O cavity mix with anions from the H cavity to form concentrated alkaline water.

[0021] The present invention has the following beneficial effects:

[0022] In the specific operation of the apparatus and method for preparing dissolved oxygen and dissolved hydrogen by electro-deionization described in this invention, pure water with added alkaline substances sequentially enters the O chamber and the first EDI component to generate oxygen-containing pure water; pure water with added alkaline substances sequentially enters the H chamber and the second EDI component to generate hydrogen-containing pure water. The concentrations of oxygen and hydrogen in the water are obtained by adjusting the current of the adjustable power supply, achieving adjustable oxygen and hydrogen addition. Furthermore, during operation, in the second EDI component, remaining anions and cations are further removed, leaving only hydrogen in the effluent; in the first EDI component, remaining anions and cations are further removed, leaving only oxygen in the effluent, thus producing dissolved oxygen and dissolved hydrogen with high purity and strong practicality. Attached Figure Description

[0023] The accompanying drawings, which form part of this specification, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0024] Figure 1 This is a structural diagram of the present invention;

[0025] Figure 2 This is a structural diagram of HO-EDI component 2.

[0026] Among them, 1 is an adjustable power supply, 2 is an HO-EDI component, 3 is a first EDI component, 4 is a second EDI component, 21 is an anode, 22 is a cathode, 23 is a cation exchange membrane, 24 is an anion exchange membrane, 25 is a cation exchange resin, 26 is a mixed ion exchange resin, and 27 is an anion exchange resin. Detailed Implementation

[0027] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0028] In the description of this invention, it should be understood that the terms "comprising" and "including" indicate the presence of the described features, integrals, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or collections thereof.

[0029] It should also be understood that the terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the invention. As used in this specification and the appended claims, the singular forms “a,” “an,” and “the” are intended to include the plural forms unless the context clearly indicates otherwise.

[0030] It should also be further understood that the term "and / or" as used in this specification and the appended claims refers to any combination and all possible combinations of one or more of the associated listed items, and includes such combinations. For example, A and / or B can represent three cases: A alone, A and B simultaneously, and B alone. Additionally, the character " / " in this invention generally indicates that the preceding and following objects have an "or" relationship.

[0031] It should be understood that although terms such as first, second, third, etc., may be used in the embodiments of the present invention to describe the preset range, these preset ranges should not be limited to these terms. These terms are only used to distinguish the preset ranges from one another. For example, without departing from the scope of the embodiments of the present invention, the first preset range may also be referred to as the second preset range, and similarly, the second preset range may also be referred to as the first preset range.

[0032] Depending on the context, the word "if" as used here can be interpreted as "when," "when," "in response to determination," or "in response to detection." Similarly, depending on the context, the phrase "if determination" or "if detection (of the stated condition or event)" can be interpreted as "when determination," "in response to determination," "when detection (of the stated condition or event)," or "in response to detection (of the stated condition or event)."

[0033] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0034] The accompanying drawings illustrate various structural schematic diagrams according to embodiments disclosed in this invention. These drawings are not to scale, and some details have been enlarged for clarity, and some details may have been omitted. The shapes of the various regions and layers shown in the drawings, as well as their relative sizes and positional relationships, are merely exemplary and may deviate from reality due to manufacturing tolerances or technical limitations. Furthermore, those skilled in the art can design regions / layers with different shapes, sizes, and relative positions as needed.

[0035] Example 1

[0036] refer to Figure 1 and Figure 2 The apparatus for preparing dissolved oxygen and dissolved hydrogen by electro-deionization according to the present invention includes an adjustable power supply 1, an HO-EDI component 2, a first EDI component 3 and a second EDI component 4;

[0037] The first outlet of the HO-EDI component 2 is connected to the inlet of the first EDI component 3, and the second outlet of the HO-EDI component 2 is connected to the inlet of the second EDI component 4. The HO-EDI component 2 includes an anode 21, a cation exchange membrane 23, an anion exchange membrane 24, and a cathode 22 arranged in sequence. The adjustable power supply 1 is connected to the anode 21 and the cathode 22. An O cavity is formed between the anode 21 and the cation exchange membrane 23, an M cavity is formed between the cation exchange membrane 23 and the anion exchange membrane 24, and an H cavity is formed between the anion exchange membrane 24 and the cathode 22. The first water inlet pipe is connected to the first EDI component 3 through the O cavity, and the second water inlet pipe is connected to the second EDI component 4 through the H cavity.

[0038] In one embodiment of the present invention, the O cavity is filled with cation exchange resin 25.

[0039] In one embodiment of the present invention, the M cavity is filled with mixed ion exchange resin 26.

[0040] In one embodiment of the present invention, the H cavity is filled with anion exchange resin 27.

[0041] In one embodiment of the present invention, pure water containing alkaline substances is sequentially passed through the O chamber and the first EDI component 3 to generate oxygenated pure water.

[0042] In one embodiment of the present invention, pure water containing alkaline substances is sequentially passed through the H chamber and the second EDI component 4 to generate hydrogen-containing pure water.

[0043] In one embodiment of the present invention, the oxygen concentration in oxygen-containing purified water and the hydrogen concentration in hydrogen-containing purified water are adjusted by adjusting the current of the adjustable power supply 1.

[0044] In one embodiment of the present invention, the alkaline substance is NaOH, KOH or NH4OH.

[0045] It should be noted that this invention significantly simplifies the oxygen or hydrogen addition device of the thermal system, providing a simpler method for controlling the concentration of dissolved oxygen or dissolved hydrogen in the system, and eliminating the safety hazards of deviation from the control index during conventional oxygen or hydrogen addition; since this invention uses the method of adjusting the amount of electricity to control the concentration of dissolved oxygen or dissolved hydrogen in the water, the adjustment process is not only easy to implement, but also allows for more precise dosage.

[0046] Example 2

[0047] refer to Figure 1 and Figure 2This embodiment discloses a method for preparing dissolved oxygen and dissolved hydrogen by electro-deionization. The method is based on a system for preparing dissolved oxygen and dissolved hydrogen by electro-deionization. This system includes a first inlet pipe, a second inlet pipe, an adjustable power supply 1, a HO-EDI component 2, a first EDI component 3, and a second EDI component 4. The first outlet of the HO-EDI component 2 is connected to the inlet of the first EDI component 3, and the second outlet of the HO-EDI component 2 is connected to the inlet of the second EDI component 4. Source 1 is connected to HO-EDI component 2; in this embodiment, HO-EDI component 2 includes an anode 21, a cation exchange membrane 23, an anion exchange membrane 24 and a cathode 22 arranged in sequence. The adjustable power supply 1 is connected to the anode 21 and the cathode 22. An O cavity is formed between the anode 21 and the cation exchange membrane 23, an M cavity is formed between the cation exchange membrane 23 and the anion exchange membrane 24, and an H cavity is formed between the anion exchange membrane 24 and the cathode 22. The first water inlet pipe is connected to the first EDI component 3 through the O cavity, and the second water inlet pipe is connected to the second EDI component 4 through the H cavity.

[0048] Specifically, the method for preparing dissolved oxygen and dissolved hydrogen by electro-deionization includes the following steps:

[0049] Pure water containing an alkaline substance is introduced into chambers O and H, respectively. In chamber O, the alkaline water undergoes an oxygen evolution reaction, and 40H... - -4e→2H2O+O 2 The original cations in the water (Na) + K + or NH4 + Most of the water passes through the cation exchange membrane 23 and enters the M chamber. The generated oxygen and the remaining anions and cations flow into the first EDI component 3 with the water flow. In the first EDI component 3, the remaining anions and cations are further removed, so that only oxygen is in the effluent.

[0050] The alkaline water in the H cavity undergoes electrolysis: 2H₂O → 2OH⁻ - +2H + Hydrogen ions gain electrons at cathode 22 and undergo hydrogen evolution reaction, 2H+ + +2e- = H2O, OH- is generated by water electrolysis. - Most of the water passes through the anion exchange membrane 24 and enters the M chamber. The generated hydrogen gas and the remaining anions and cations flow into the second EDI component 4 with the water flow. In the second EDI component 4, the remaining anions and cations are further removed, and the effluent contains only hydrogen gas.

[0051] In cavity M, cations (Na) from cavity O... + K + or NH4 +) and anions (OH) from the H cavity - The mixture forms concentrated alkaline water, which is then discharged and reused.

[0052] In one embodiment of the present invention, the O cavity is filled with cation exchange resin 25.

[0053] In one embodiment of the present invention, the M cavity is filled with mixed ion exchange resin 26.

[0054] In one embodiment of the present invention, the H cavity is filled with anion exchange resin 27.

[0055] In one embodiment of the present invention, the oxygen concentration in oxygen-containing purified water and the hydrogen concentration in hydrogen-containing purified water are adjusted by adjusting the current of the adjustable power supply 1.

[0056] In one embodiment of the present invention, the alkaline substance is NaOH, KOH or NH4OH.

[0057] It should be noted that this invention utilizes the reaction between the anode and cathode by changing the order of the ion exchange membranes between the original EDI plates and the type of resin used to prepare oxygen and hydrogen in an adjustable manner.

[0058] Example 3

[0059] Taking oxygenation in thermal power plants as an example, conventional oxygenation processes using gaseous oxygen cannot stably control the oxygen dosage. On the one hand, the oxidation reaction cannot proceed continuously and stably, resulting in poor corrosion prevention. On the other hand, excessive residual oxygen on the steam side often leads to excessive dissolved oxygen levels, potentially accelerating oxide scale shedding. Furthermore, due to significant fluctuations in oxygen levels when the unit load changes, it is impossible to ensure both sufficient and complete oxidation on the boiler water side while avoiding excessive oxygenation that could adversely affect the boiler steam side. In contrast to gaseous oxygenation, liquid oxygenation technology has been developed, significantly improving the accuracy of oxygenation. It ensures high-precision automatic operation of the oxygenation process under any conditions, automatically controlling the oxygen dosage within ±3 μg / L of the set value. Liquid oxygenation typically requires oxygen cylinders and dissolved oxygen tanks to saturate the water with oxygen.

[0060] The present invention differs from the above in that it uses an electrochemical method to prepare dissolved oxygen water, which can replace the oxygen cylinder, dissolved oxygen tank, and metering pump in the above system. The invention will be illustrated using water containing added NH4OH as an example. A 5%-10% NH4OH solution is introduced into the three chambers of the HO-EDI component 2. An oxygen evolution reaction occurs in the alkaline water in the O chamber, and after 40 hours… - -4e→2H2O+O 2 The cation NH4 in the water +Most of the oxygen passes through the cation exchange membrane 23 and enters the M chamber. The generated oxygen and the remaining anions and cations flow into the water purification chamber of the first EDI component 3. In the first EDI component 3, the remaining NH4OH anions and cations are further removed, so that only oxygen is in the effluent of the first EDI component 3. The effluent is then pumped into the water and steam system of the thermal power plant to achieve the purpose of regulating dissolved oxygen.

[0061] Example 4

[0062] Pressurized water reactor nuclear power plants typically do not have a hydrogen addition system. Instead, hydrogen concentration in their systems is generated by adjusting the ammonia concentration in the primary coolant and then decomposing the ammonia through irradiation. Changes in hydrogen concentration lag behind ammonia concentration changes, and the release of potassium from changes in ammonia in the purification system resin usually lags by more than 8 hours. Improper operation can easily lead to deviations in water quality.

[0063] This invention can supplement hydrogen concentration control in pressurized water reactor nuclear power plants. Taking water containing added NH4OH as an example, the invention is illustrated. A solution with an NH4OH concentration of 5%-10% is introduced into the three chambers of HO-EDI assembly 2. In chamber H, alkaline water undergoes electrolysis: 2H2O → 2OH-. - +2H + Hydrogen ions gain electrons at cathode 22 and undergo hydrogen evolution reaction, 2H+ + +2e- = H2O, OH- is generated by water electrolysis. - Most of the water passes through the anion exchange membrane 24 and enters the M chamber. The generated hydrogen gas and the remaining NH4OH anions and cations flow into the water purification chamber of the second EDI module 4. In the second EDI module 4, the remaining anions and cations are further removed, and the effluent contains only hydrogen gas. The effluent is then pumped into the primary loop of the nuclear power plant to achieve the purpose of regulating the dissolved hydrogen concentration.

[0064] Other embodiments of the invention will readily occur to those skilled in the art upon consideration of the specification and disclosure of the invention. This application is intended to cover any variations, uses, or adaptations of the invention that follow the general principles of the invention and include common knowledge or customary techniques in the art not disclosed herein. The specification and examples are to be considered exemplary only, and the true scope and spirit of the invention are indicated by the following claims.

[0065] It should be understood that the present invention is not limited to the precise structure described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of the invention is limited only by the appended claims.

[0066] The above description is merely a preferred embodiment of the present invention and does not constitute any limitation on the present invention. Any simple modifications, alterations, or equivalent structural changes made to the above embodiments based on the technical essence of the present invention shall still fall within the protection scope of the present invention.

Claims

1. An apparatus for producing dissolved oxygen and dissolved hydrogen by electrodialysis, characterized by comprising: The device comprises an adjustable power supply (1), a HO-EDI assembly (2), a first EDI assembly (3) and a second EDI assembly (4). The first outlet of the HO-EDI assembly (2) is connected with the inlet of the first EDI assembly (3), the second outlet of the HO-EDI assembly (2) is connected with the inlet of the second EDI assembly (4), and the adjustable power supply (1) is connected with the HO-EDI assembly (2). The device further comprises a first water inlet pipeline and a second water inlet pipeline, and the HO-EDI assembly (2) comprises an anode (21), a cation exchange membrane (23), an anion exchange membrane (24) and a cathode (22) arranged in sequence, wherein the adjustable power supply (1) is connected with the anode (21) and the cathode (22), the O cavity is formed between the anode (21) and the cation exchange membrane (23), the M cavity is formed between the cation exchange membrane (23) and the anion exchange membrane (24), the H cavity is formed between the anion exchange membrane (24) and the cathode (22), the first water inlet pipeline is connected with the first EDI assembly (3) through the O cavity, and the second water inlet pipeline is connected with the second EDI assembly (4) through the H cavity. The O cavity is filled with cation exchange resin (25). The M cavity is filled with mixed ion exchange resin (26). The H cavity is filled with anion exchange resin (27). Pure water added with an alkaline substance generates oxygen-containing pure water through the O cavity and the first EDI assembly (3) in sequence. Pure water added with an alkaline substance generates hydrogen-containing pure water through the H cavity and the second EDI assembly (4) in sequence.

2. The device for preparation of dissolved oxygen and dissolved hydrogen by electrodeionization according to claim 1, characterized in that, The alkaline substance is NaOH, KOH or NH4OH.

3. The device for preparation of dissolved oxygen and dissolved hydrogen by electrodeionization according to claim 1, characterized in that, The oxygen concentration in the oxygen-containing pure water and the hydrogen concentration in the hydrogen-containing pure water are adjusted by adjusting the current of the adjustable power supply (1).

4. A method for producing dissolved oxygen and dissolved hydrogen by electrodeionization, characterized by, The device for preparing dissolved oxygen and dissolved hydrogen by electro-deionization according to claim 1 comprises the following steps: The pure water added with an alkaline substance enters the O cavity and the H cavity respectively, wherein the alkaline water in the O cavity generates an oxygen evolution reaction, most of the original cations in the water pass through the cation exchange membrane (23) and enter the M cavity, the generated oxygen and the remaining anions and cations flow into the first EDI assembly (3) with the water, and the remaining anions and cations are further removed in the first EDI assembly (3), so that the effluent only contains oxygen; H chamber, hydrogen ions get electrons on the cathode (22) to generate hydrogen evolution reaction, OH - Most of them pass through the anion exchange membrane (24) into the M chamber, the generated hydrogen and the remaining anions and cations flow into the second EDI component (4) with water, and in the second EDI component (4), the remaining anions and cations are further removed, and the water only contains hydrogen. In the M cavity, the cations from the O cavity and the anions from the H cavity are mixed to form concentrated alkaline water.

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