A composition for promoting continuous production of vanadium electrolyte and application thereof

Abstract

The application relates to the technical field of a vanadium redox flow battery, and specifically discloses a composition for promoting continuous production of vanadium electrolyte and application of the composition. The composition for promoting continuous production of vanadium electrolyte is characterized in that the composition specifically comprises the following components in parts by weight: concentrated sulfuric acid 32-42 parts, a sulfonic acid compound 0.8-1.2 parts, sodium sulfate 0.05-0.15 parts, and water 60-66 parts; the sulfonic acid compound is selected from any one or more of methyl sulfonic acid, ethyl sulfonic acid, benzene sulfonic acid, amino sulfonic acid and p-toluene sulfonic acid. The composition provided by the application is used in continuous production of vanadium electrolyte, can effectively activate vanadium pentoxide and accelerate the reaction rate while reducing the use amount of concentrated sulfuric acid, and the produced vanadium electrolyte has excellent electrochemical performance.

Description

Technical Field

[0001] This application relates to the technical field of vanadium redox flow batteries, and more specifically to a composition that facilitates the continuous production of vanadium electrolyte and its application. Background Technology

[0002] In vanadium redox flow batteries, vanadium electrolyte is a core component, and its performance and quality directly determine the overall performance, cycle life, and operational stability of the battery. Currently, a common method in the production process of vanadium sulfate electrolyte is to react high-purity vanadium pentoxide with an organic reducing agent under acidic conditions. In this reaction system, high-purity vanadium pentoxide serves as the vanadium source, the organic reducing agent provides the reducing environment, and the acidic conditions facilitate the reaction and product stability. By precisely controlling reaction conditions, such as reaction temperature, reaction time, acidity, and the amount of reducing agent, pentavalent vanadium in vanadium pentoxide can be reduced to tetravalent vanadium, thus producing a tetravalent vanadium electrolyte. Subsequently, the tetravalent vanadium electrolyte is further processed by electrolysis. By adjusting electrolysis parameters, such as electrolysis voltage, current density, and electrolysis time, the conversion of tetravalent vanadium to 3.5 valence is achieved, ultimately yielding an initial 3.5 valence electrolyte.

[0003] The above methods can meet the production needs of vanadium electrolyte to a certain extent. However, in actual continuous production processes, when using only trivalent vanadium electrolyte to reduce pentavalent vanadium (existing in the form of high-purity vanadium powder) electrolyte, a large amount of undissolved, viscous tetravalent vanadium intermediates will be generated during continuous production. Specifically, in the reaction system, trivalent vanadium and pentavalent vanadium undergo a redox reaction, which should theoretically directly produce vanadium compounds with a valence of 3.5. However, due to reaction kinetics, uneven mixing of reactants, and insufficient precision in controlling reaction conditions, some pentavalent vanadium is not completely reduced to 3.5, instead generating tetravalent vanadium intermediates. These tetravalent vanadium intermediates gradually accumulate in the reaction system, exhibiting a viscous state due to their special chemical properties and physical state.

[0004] This viscous vanadium tetroxide intermediate has a serious negative impact on continuous production. Filtration is a crucial step in the production process, used to separate solid impurities and unreacted raw materials from the reaction products to ensure the high purity of the final vanadium electrolyte. However, the viscous vanadium tetroxide intermediate easily adheres to the filter screen surface and pores, causing filter blockage. Once the filter is blocked, the flow of materials in the reaction system is hindered, preventing reactants from smoothly entering the reaction zone and products from being discharged in a timely manner, thus disrupting the rhythm and balance of the entire production process. This not only reduces the overall output of the production line and increases production costs but may also affect product quality and stability, and in severe cases, even lead to production interruption, causing huge economic losses to the company.

[0005] In summary, the existing technology has inconveniences and defects in the practical application of continuous production of vanadium sulfate electrolyte, so it is necessary to improve it. Summary of the Invention

[0006] To address the aforementioned technical problems, this application provides a composition that promotes continuous production of vanadium electrolyte and its application.

[0007] In a first aspect, this application provides a composition for promoting the continuous production of vanadium electrolyte, specifically comprising the following components in parts by weight: 32-42 parts concentrated sulfuric acid, 0.8-1.2 parts sulfonic acid compound, 0.005-0.015 parts sodium sulfate, and 60-66 parts water;

[0008] The sulfonic acid compound is selected from any one or more of methanesulfonic acid, ethanesulfonic acid, benzenesulfonic acid, aminosulfonic acid, and p-toluenesulfonic acid.

[0009] The purpose of this application is to provide a composition that promotes the continuous production of vanadium electrolyte, and to solve the problem that viscous vanadium tetroxide is generated during the continuous production of vanadium sulfate electrolyte, causing filter blockage and reducing the output of the entire production line.

[0010] The composition provided in this application utilizes concentrated sulfuric acid to provide strong acidic conditions that facilitate the dissolution of vanadium pentoxide, ensuring smooth reaction and product stability. The sulfonic acid groups provided by the sulfonic acid compound effectively activate vanadium pentoxide, increasing the solubility of vanadium ions. Sodium sulfate promotes the dissociation of vanadium oxide through ion exchange. The synergistic effect of these three components accelerates the dissolution and reaction process of vanadium pentoxide. Furthermore, the composition system introduces fewer impurities, effectively ensuring that the vanadium electrolyte produced has excellent electrochemical performance.

[0011] Preferably, the composition for promoting continuous production of vanadium electrolyte specifically comprises the following components in parts by weight: 34-40 parts concentrated sulfuric acid, 0.9-1.1 parts sulfonic acid compound, 0.007-0.012 parts sodium sulfate, and 62-64 parts water.

[0012] In one specific embodiment, the composition for promoting continuous production of vanadium electrolyte specifically comprises the following components in parts by weight: 36 parts concentrated sulfuric acid, 1 part sulfonic acid compound, 0.1 parts sodium sulfate, and 63 parts water.

[0013] Preferably, the sulfonic acid compound is composed of a mixture of methanesulfonic acid and benzenesulfonic acid in a weight ratio of 10-20:1-5.

[0014] Preferably, the sulfonic acid compound is composed of a mixture of methanesulfonic acid and benzenesulfonic acid in a weight ratio of 13-17:2-4.

[0015] In one specific embodiment, the weight ratio of methanesulfonic acid to benzenesulfonic acid in the sulfonic acid compound can be 10:1, 10:2, 10:3, 10:4, 10:5, 13:1, 13:2, 13:3, 13:4, 13:5, 15:1, 15:2, 15:3, 15:4, 15:5, 17:1, 17:2, 17:3, 17:4, 17:5, 20:1, 20:3, or 20:5.

[0016] Experimental analysis shows that the combination of methanesulfonic acid and benzenesulfonic acid in the above weight ratio to form a sulfonic acid compound helps to improve reaction efficiency and electrochemical activity of the finished vanadium electrolyte, and can further improve the application effect of the composition in the continuous production of vanadium electrolyte.

[0017] Secondly, this application provides the application of the above-mentioned composition for promoting continuous production of vanadium electrolyte in the continuous production of vanadium electrolyte.

[0018] Thirdly, this application provides a method for continuous production of vanadium electrolyte, using the aforementioned composition; specifically, it includes the following steps performed sequentially:

[0019] On a continuous production line, trivalent vanadium electrolyte, vanadium pentoxide, and a composite material are fed into the reactor at a constant feeding rate; after being stirred evenly, the mixture is pumped into an aging tank by a slurry pump for aging reaction; the temperature of the aging reaction is 70±5℃.

[0020] After the aging reaction is completed, the reaction solution is cooled and filtered. The filtrate is mixed with an equal amount of trivalent vanadium electrolyte to obtain a vanadium electrolyte with a 3.5 valence.

[0021] Preferably, the feeding rate of the trivalent vanadium electrolyte is 9-11 m / s. 3 The feeding rate of vanadium pentoxide is 900-1000 kg / h, and the feeding rate of the composition is 9000-11000 kg / h; the trivalent vanadium electrolyte contains 1.5-1.9 mol / L V. 3+ 4.1-4.5 mol / L SO4 2- The electrolyte.

[0022] In the continuous production method of vanadium electrolyte, by controlling the feeding rate of trivalent vanadium electrolyte and vanadium pentoxide composition, a finished vanadium electrolyte with a concentration that can be precisely controlled is obtained.

[0023] Preferably, the aging reaction temperature is 70±2℃.

[0024] Preferably, the stirring speed of the aging reaction is 100-200 rpm, and the reaction time is 2-4 h.

[0025] Preferably, the filtration accuracy is 0.1µm.

[0026] In summary, the technical solution of this application has the following effects:

[0027] This application selects specific amounts of concentrated sulfuric acid, sulfonic acid compounds, sodium sulfate, and water as the composition for preparing vanadium electrolyte. Through conventional aging reaction, a vanadium electrolyte with a valence of 3.5 is obtained, which facilitates large-scale continuous production and manufacturing.

[0028] The composition provided in this application is used in the continuous production of vanadium electrolyte, which reduces the amount of concentrated sulfuric acid used and saves production costs; it can effectively activate vanadium pentoxide, accelerate the reaction rate, and shorten the preparation time; and the vanadium electrolyte produced has excellent electrochemical performance, making the quality of the product easy to control. Detailed Implementation

[0029] The present application will be further described in detail below with reference to embodiments, comparative examples and performance test results. These embodiments should not be construed as limiting the scope of protection claimed in this application.

[0030] Example

[0031] Example 1

[0032] Example 1 provides a composition for promoting continuous production of vanadium electrolyte and a method for continuous production of vanadium electrolyte.

[0033] The composition in Example 1 was prepared by adding 3690 kg of concentrated sulfuric acid (H2SO4, 98% concentration), 100 kg of a sulfonic acid compound (composed of methanesulfonic acid and benzenesulfonic acid in a weight ratio of 13:4), and 1 kg of sodium sulfate to 6300 kg of water and mixing thoroughly. That is, the composition consists of the following components in parts by weight: 36.9 parts concentrated sulfuric acid, 1 part sulfonic acid compound, 0.01 parts sodium sulfate, and 63 parts water (each part represents 100 kg).

[0034] The method for continuous production of vanadium electrolyte in the above embodiments is as follows:

[0035] Process conditions: On a continuous production line, 10m³ of material is fed into the reactor at a constant feed rate. 3 / h trivalent vanadium electrolyte (from the cathode circulation tank in the electrolytic cell, the trivalent vanadium electrolyte contains 1.7 mol / L) 3+ 4.3 mol / L SO4 2-The electrolyte, 965 kg / h vanadium pentoxide (V2O5, purity ≥99.5%), and 10000 kg / h composition were mixed evenly and then pumped into an aging tank by a slurry pump for aging reaction. The aging reaction temperature was 70±5℃ and the stirring speed was 150 rpm until the reaction was completed to obtain tetravalent vanadium reaction solution.

[0036] Results and Observations: Under the above conditions, the reaction system was a stable deep blue solution, indicating that pentavalent vanadium was fully reduced to tetravalent vanadium. Online monitoring and sampling analysis, through tracking changes in the solid content within the reactor, determined that the complete dissolution and aging time of vanadium pentoxide solid was 2.5 h. The reaction process was stable and thorough, without violent exothermic reactions or foaming, making it easy to control industrially. The resulting reaction solution had a tetravalent vanadium concentration of 1.70 mol / L and a total sulfate concentration of 4.3 mol / L.

[0037] After the aging reaction is complete, the reaction solution is cooled to below 50°C. The solution is then pumped into a precision filter (0.1µm) at the bottom of the aging tank via a slurry pump. After filtration, the solution is discharged at a concentration of 15m... 3 A flow rate of / h enters the intermediate tank; a portion enters at 12.5m³ / h. 3 Feed is introduced into the cathode circulation tank of the electrolytic cell at a flow rate of / h, with a portion flowing at 2.5m³ / h. 3 The feed rate is / h and it is fed into the finished product mixing tank at a feeding speed of 2.5m. 3 An equimolar amount of trivalent vanadium electrolyte (from the cathode circulation tank in the electrolytic cell, the trivalent vanadium electrolyte contains 1.7 mol / L) per hour. 3+ 4.3 mol / L SO4 2- The electrolyte is mixed to obtain a vanadium electrolyte with a valence of 3.5.

[0038] Examples 2-5

[0039] Examples 2-5 respectively provide a composition for promoting continuous production of vanadium electrolyte and a method for continuous production of vanadium electrolyte.

[0040] The difference in the above embodiments is that the amount of each raw material component in the composition is different, as shown below.

[0041] In Example 2: 3690 kg of concentrated sulfuric acid, 80 kg of sulfonic acid compound, and 1 kg of sodium sulfate were added to 6320 kg of water.

[0042] In Example 3: 3690 kg of concentrated sulfuric acid, 120 kg of sulfonic acid compound, and 1 kg of sodium sulfate were added to 6280 kg of water.

[0043] In Example 4: 3690 kg of concentrated sulfuric acid, 100 kg of sulfonic acid compound, and 0.5 kg of sodium sulfate were added to 6305 kg of water.

[0044] In Example 5: 3690 kg of concentrated sulfuric acid, 100 kg of sulfonic acid compound, and 1.5 kg of sodium sulfate were added to 6295 kg of water.

[0045] All other process parameters in the above embodiments are the same as those in Embodiment 1.

[0046] Examples 6-10

[0047] Examples 6-10 respectively provide a composition for promoting continuous production of vanadium electrolyte and a method for continuous production of vanadium electrolyte.

[0048] The difference between the above embodiments and Embodiment 1 is that the types of sulfonic acid compounds are different, as shown below.

[0049] In Example 6: The sulfonic acid compound is composed of methanesulfonic acid and aminosulfonic acid in a weight ratio of 13:4.

[0050] In Example 7: The sulfonic acid compound is composed of a mixture of ethanesulfonic acid and benzenesulfonic acid in a weight ratio of 13:4.

[0051] In Example 8: the sulfonic acid compound is composed of methanesulfonic acid and benzenesulfonic acid in a weight ratio of 4:13.

[0052] In Example 9: The sulfonic acid compound is composed of a mixture of methanesulfonic acid and benzenesulfonic acid in a weight ratio of 20:1.

[0053] In Example 10: the sulfonic acid compound is composed of a mixture of methanesulfonic acid and benzenesulfonic acid in a weight ratio of 17:2.

[0054] All other process parameters in the above embodiments are the same as those in Embodiment 1.

[0055] Comparative Example

[0056] Comparative Examples 1-4

[0057] Comparative Examples 1-4 respectively provide a composition and a method for continuous production of vanadium electrolyte.

[0058] The difference between the above comparative examples and Example 1 is that the composition of the compositions is different, as shown below.

[0059] In Comparative Example 1: In the composition, an equal amount of magnesium sulfate was used instead of sodium sulfate.

[0060] In Comparative Example 2: Sodium sulfate was replaced with an equal amount of water in the composition.

[0061] In Comparative Example 3, 3690 kg of concentrated sulfuric acid, 100 kg of sulfonic acid compound, and 0.1 kg of sodium sulfate were added to 6308 kg of water.

[0062] In Comparative Example 4, 3690 kg of concentrated sulfuric acid, 130 kg of sulfonic acid compounds, and 1 kg of sodium sulfate were added to 6270 kg of water, respectively.

[0063] All other process parameters in the above comparative examples are the same as those in Example 1.

[0064] Performance testing

[0065] Reaction efficiency: The complete dissolution of vanadium pentoxide solid and the aging reaction time were observed using the methods provided in the examples and comparative examples.

[0066] Electrochemical performance of vanadium electrolyte: Charge-discharge tests were conducted on the vanadium electrolytes with a valence of 3.5 prepared in the examples and comparative examples. Charge-discharge curves were recorded, and energy efficiency, capacity retention (based on a current density of 160 Ω and 100 effective cycles), and cycle life performance indicators were calculated.

[0067] Test results are shown in Table 1.

[0068] Table 1 Performance test results in the examples and comparative examples

[0069]

[0070] As can be seen from the test results in Table 1 above, the composition is suitable for continuous production of vanadium electrolyte using the technical solution provided in this application. It can effectively activate vanadium pentoxide and accelerate the reaction rate while reducing the amount of concentrated sulfuric acid used. Moreover, the vanadium electrolyte produced has excellent electrochemical performance.

[0071] By comparing the test results of Examples 1, 4-5, and Comparative Examples 1-3, it can be seen that in Comparative Example 1, an equal amount of magnesium sulfate was used instead of sodium sulfate in the composition; in Comparative Example 2, an equal amount of water was used instead of sodium sulfate in the composition. This resulted in a longer complete dissolution time for vanadium pentoxide solid, a slower reaction rate, and poorer electrochemical performance of the vanadium electrolyte. In Comparative Example 3, the amount of sodium sulfate used was relatively small, leading to a longer complete dissolution time for vanadium pentoxide solid and a slower reaction rate. In contrast, this application uses a specific amount of sodium sulfate as a raw material for the composition, effectively improving the reaction efficiency, and the resulting vanadium electrolyte exhibits excellent electrochemical performance.

[0072] By comparing the test results of Examples 1-3 and Comparative Example 4, it can be seen that Comparative Example 4 uses a larger amount of sulfonic acid compounds, which increases the economic cost and results in a vanadium electrolyte with poor electrochemical performance. In contrast, this application uses a specific amount of sulfonic acid compounds as raw materials for the composition, which improves the reaction efficiency and results in a vanadium electrolyte with excellent electrochemical performance.

[0073] Comparing the test results of Examples 1 and 6-10, it can be seen that in Example 6, the sulfonic acid compound was composed of a mixture of methanesulfonic acid and aminosulfonic acid in a weight ratio of 13:4. The electrolyte product was found to contain ammonium ion impurities, which interact with vanadium ions, resulting in a slower reaction rate and reduced electrochemical performance of the final vanadium electrolyte. In Example 7, the sulfonic acid compound was composed of a mixture of ethanesulfonic acid and benzenesulfonic acid in a weight ratio of 13:4, and the reaction rate increased slowly. In Example 8, the sulfonic acid compound was composed of a mixture of methanesulfonic acid and benzenesulfonic acid in a weight ratio of 4:13, and the reaction rate increased slowly. In contrast, this application uses a mixture of methanesulfonic acid and benzenesulfonic acid in a weight ratio of 10-20:1-5 to form the sulfonic acid compound, which does not introduce impurities affecting electrochemical activity, thus helping to improve electrochemical activity and further enhancing the application effect of the composition in the continuous production of vanadium electrolyte.

[0074] Although the present invention has been described in detail above with general descriptions and specific embodiments, modifications or improvements can be made to it, which will be obvious to those skilled in the art. Therefore, all such modifications or improvements made without departing from the spirit of the present invention fall within the scope of protection claimed by the present invention.

Claims

1. A composition for promoting continuous production of vanadium electrolyte, characterized in that, Specifically, it includes the following components by weight: 32-42 parts concentrated sulfuric acid, 0.8-1.2 parts sulfonic acid compounds, 0.005-0.015 parts sodium sulfate, and 60-66 parts water; The sulfonic acid compound is composed of a mixture of methanesulfonic acid and benzenesulfonic acid in a weight ratio of 10-20:1-5; In a method to promote continuous production of vanadium electrolyte, by controlling the feeding rate of trivalent vanadium electrolyte and vanadium pentoxide composition, a finished vanadium electrolyte with controllable concentration of 3.5 valence can be obtained.

2. The composition for promoting continuous production of vanadium electrolyte according to claim 1, characterized in that, Specifically, it includes the following components by weight: 34-40 parts concentrated sulfuric acid, 0.9-1.1 parts sulfonic acid compounds, 0.007-0.012 parts sodium sulfate, and 62-64 parts water.

3. The composition for promoting continuous production of vanadium electrolyte according to claim 1, characterized in that, The sulfonic acid compound is composed of a mixture of methanesulfonic acid and benzenesulfonic acid in a weight ratio of 13-17:2-4.

4. The use of the composition for promoting continuous production of vanadium electrolyte as described in any one of claims 1-3 in the continuous production of vanadium electrolyte.

5. A method for continuous production of vanadium electrolyte, characterized in that, Production is carried out using the composition according to any one of claims 1-3; specifically, it includes performing the following steps in sequence: On a continuous production line, trivalent vanadium electrolyte, vanadium pentoxide, and a composite material are fed into a reactor at a constant feeding rate. After being stirred evenly, the mixture is pumped into an aging tank by a slurry pump for aging reaction. The feeding rate ratio of vanadium pentoxide to the composite material is 1:8-12. The temperature of the aging reaction is 70±5℃. After the aging reaction is completed, the reaction solution is cooled and filtered. The filtrate is mixed with an equal amount of trivalent vanadium electrolyte to obtain a vanadium electrolyte with a 3.5 valence.

6. The method for continuous production of vanadium electrolyte according to claim 5, characterized in that, The feeding rate of the trivalent vanadium electrolyte is 9-11 m / s. 3 The feeding rate of vanadium pentoxide is 900-1000 kg / h, and the feeding rate of the composition is 9000-11000 kg / h; the trivalent vanadium electrolyte contains 1.5-1.9 mol / L V. 3+ 4.1-4.5 mol / L SO4 2- The electrolyte.

7. The method for continuous production of vanadium electrolyte according to claim 5, characterized in that, The aging reaction was carried out at a temperature of 70±2℃.

8. The method for continuous production of vanadium electrolyte according to claim 5, characterized in that, The stirring speed for the aging reaction is 100-200 rpm, and the reaction time is 2-4 hours.

9. The method for continuous production of vanadium electrolyte according to claim 5, characterized in that, The filtration accuracy is 0.1 μm.

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