System and method for preparing high-activity and high-purity vanadium electrolyte with specific valence state

Abstract

The invention belongs to the field of chemical industry and energy and provides a system and method for preparing a high-activity and high-purity vanadium electrolyte with a specific valence state. The method comprises the steps of transforming industrial vanadium oxide into vanadium trichloride oxide by using fluidzed chlorination and obtaining crude vanadium trichloride oxide through dedusting and leaching; obtaining high-purity and low-valence vanadium oxide through rectification, catalytic oxidation and precise control reduction, wherein the average valence state of vanadium can be any value from 3.0 to 4.0; and adding pure water and a pure sulfuric acid solution for low-temperature dissolution under the action of an activation device to obtain the high-activity and high-purity vanadium electrolyte with the specific valence state, wherein the high-activity and high-purity vanadium electrolyte can be directly applied to an all-vanadium redox flow battery. According to the system andthe method, the reaction efficiency is improved through arranging an internal component in a catalytic oxidation fluidized bed; the reductive degree is regulated through arranging a vertical baffle plate and discharge openings of different heights in a reduced fluidized bed; and the activity of the vanadium electrolyte is improved through activating treatment. The system and the method have the advantages of being high in raw material adaptability, free of pollution, low in production energy consumption and operation cost, stable in product quality and suitable for large-scale industrial production.

Description

technical field [0001] The invention belongs to the fields of chemical industry and energy, and in particular relates to a system and method for preparing high-activity and high-purity specific valence-state vanadium electrolyte. Background technique [0002] Traditional fossil fuels have always been the main source of energy. Due to long-term mining and extensive use, they are facing the problem of resource depletion, and also bring serious environmental pollution. The development and utilization of clean and renewable energy such as wind energy, water energy, solar energy, and tidal energy has gradually attracted the attention of human society. However, renewable energy is inherently intermittent, and existing energy management systems are difficult to use effectively. [0003] Energy storage technology is one of the ways to solve such problems. Among various energy storage systems, vanadium redox flow battery (VRB) is an attractive energy storage device. The biggest ad...

AI Technical Summary

Problems solved by technology

When the impurity concentration in the electrolyte is high, it will bring the following problems: (1) There is a competitive reaction between impurity ions and vanadium ions, reducing battery efficiency

(2) In the positive electrode chamber, impurity ions are deposited on the graphite felt electrode, which blocks the gaps of the graphite felt and reduces the specific surface area of ​​the graphite felt, thereby affecting the charge and discharge efficiency

(3) In the negative electrode chamber, impurity ions will affect the hydrogen evolution overpotential, and gas production will affect the pressure balance inside the battery

(4) Impurity ions reduce the life of the proton exchange membrane

(5) Impurity ions affect the stability of vanadium ions, resulting in premature aging of the electrolyte

The main problem that this patent exists is: no specific reduction process is given, reducing V in hydrogen 2 o 5 Preparation V 2 o 4 Powder, it is easy to have the situation of over-reduction or under-reduction, which needs precise control to realize, and the measures for precise control of reduction are not listed in the patent; the purity is low; CN101880059A and CN102557134A disclose a fluid state for producing high-purity vanadium trioxide The reduction furnace and reduction method, through adding heat transfer internal components in the fluidized bed, to achieve enhanced heat transfer; using cyclone preheating to improve energy utilization, to achieve V 2 o 3 Efficient preparation of

This patent has the following deficiencies: (1) Similar to the aforementioned Iowa State University research, this patent actually only provides the principle process of chlorination and lacks specific operable solutions. For example, the chlorination method includes boiling chlorine chlorination, including molten salt chlorination, and molten salt chlorination and boiling chlorination are completely different chlorination methods; for another example, it is proposed to use "rotary kiln, fluidized furnace, fluidized furnace, shaft furnace, "Multi-hearth furnace" and other reactors actually cover almost all commonly used mainstream reactors in the field of metallurgical industry, but different reactors have very different requirements for raw materials. The shaft furnace can only handle "coarse" particles larger than 8mm. "Fine particles" require pelletizing and pre-sintering treatment, and boiling chlorination is generally suitable for processing fine particles, so for a specific vanadium raw material, it cannot be directly applied to rotary kilns, fluidized furnaces, fluidized fluidized furnaces, shaft furnaces, multi- Hearth furnace and other reactors; besides, "fluidized furnace" and "fluidized fluidized furnace" are essentially the same, but they are called differently; it can be seen that because the operation methods and conditions of these reactors are very different, only the principle process is given. (2) vanadium oxychloride is passed into ultrapure aqueous solution and hydrolyzed, because vanadium pentoxide is very easy to dissolve in hydrochloric acid solution, the precipitation recovery rate of vanadium is too low; When HCl concentration is greater than 6.0mol / L In the hydrochloric acid solution, when vanadium pentoxide dissolves, it will be reduced to VOCl 2 , release chlorine gas simultaneously, and this will further reduce the precipitation recovery rate of vanadium; Precipitation and washing process will certainly produce a large amount of vanadium-containing hydrochloric acid solution, be difficult to realize comprehensive treatment effectively; (3) vanadium oxychloride is directly passed into ammoniacal solution Ammonium salt precipitation is carried out in the precipitation washing process, and there is also a large amount of ammonia nitrogen wastewater generated during the precipitation washing process, which is difficult to deal with and easily causes environmental pollution.

[0010] In addition, for large-scale industrial applications, the existing high-activity and high-purity specific valence-state vanadium electrolyte preparation technology still has the following four problems: (1) In the process of high-purity vanadium pentoxide preparation technology, the chlorination of vanadium raw materials belongs to In a strong exothermic process, the heat generated by the chlorination reaction can satisfy the preheating of the solid and gas reaction materials, but there is still a large amount of surplus, which will lead to local overheating of the vanadium material, affecting the fluidization state and the selectivity of chlorination. It is necessary to find an effective The method removes heat from the fluidized bed; (2) in the preparation process of high-purity vanadium pentoxide, the preparation of vanadium pentoxide by vanadium oxychloride still does not have an efficient preparation method that is beneficial to large-scale operation

Vanadium oxychloride is directly fed into pure water or ammonia water process, the recovery rate is low, the environmental pollution is big, and it is difficult to realize large-scale industrialization; (3) vanadium-containing ammonium salt and vanadium pentoxide lack mature precise control reduction technology; (4) There is no effective preparation technology for preparing vanadium electrolyte by dissolving low-valent vanadium oxide at room temperature

Images