KR20230081090A - Reactor for manufacturing vanadium electrolyte - Google Patents

Abstract

The present invention relates to a reactor for producing a vanadium electrolyte and a method for producing a vanadium electrolyte. The method of the present invention requires no catalyst support. The method of the present invention has no loss of a catalyst. The method of the present invention has a fast production rate. The present invention includes: a discharge unit for discharging a mixture; and a filtration unit positioned on the side of the discharge unit and including a plurality of pores to separate a solid catalyst.

Description

Reactor for manufacturing vanadium electrolyte {Reactor for manufacturing vanadium electrolyte}

The present invention relates to a reactor for preparing a vanadium electrolyte. The reactor has a shape different from the conventional ones.

The present invention relates to a method for preparing a vanadium electrolyte solution. Specifically, the method for preparing a vanadium electrolyte of the present invention uses the reactor for preparing the vanadium electrolyte.

The present invention relates to a method for preparing an electrolyte solution for a vanadium ion battery.

As the electric vehicle market is growing rapidly, the battery market is also growing rapidly. Currently, the batteries that make up the majority of the market are lithium-ion batteries. However, lithium ion batteries have a risk of fire. Therefore, it is necessary to eliminate this risk of fire or to introduce a different type of battery that can replace lithium ion batteries.

Recently, vanadium ion batteries have been developed to replace lithium ion batteries. A vanadium ion battery has a structure different from that of a conventional vanadium redox flow battery (VRFB). A study was conducted on an electrolyte solution applied to a vanadium ion battery. An electrolyte solution applied to a vanadium ion battery is an electrolyte solution containing a tetravalent vanadium compound (V(IV)) using vanadium pentoxide (V ₂ O ₅ ) as a starting material. When the corresponding electrolyte is used in a vanadium battery, the positive electrode where the oxidation reaction of V(IV) to V(V) occurs during charging and the reduction reaction of V(IV) to V(II) (V(IV) to V(III) After reduction to V(III) to V(II), the amount of electrolyte required for each cathode where the reduction of V(III) to V(II) occurs varies. Therefore, in order to match the ratio of the electrolyte required for both electrodes, the vanadium electrolyte is converted into V (III/IV) form and distributed. Here, V(III/IV) is a solution in which a trivalent vanadium compound (V(III)) and a tetravalent vanadium compound (V(IV)) are mixed in a volume ratio of about 1:1. Electrolytes distributed in the form of V(III/IV) are usually called vanadium electrolytes. As a method for preparing the vanadium electrolyte, three methods are known.

The first method is an electrochemical method (see FIG. 1). In the electrochemical method, while using tetravalent vanadium as the positive and negative electrolytes of the flow battery, the SOC (State Of Charge) of the flow battery is set to about 50%, and approximately half of the tetravalent vanadium is reduced in the negative electrolyte. It is a method of obtaining a vanadium electrolyte. The electrochemical method requires a process of recycling the vanadium electrolyte obtained from the anode electrolyte, and it is difficult to precisely match the volume ratio of V(III) and V(IV).

The second method is the reducing agent method. The reducing agent method is a relatively simple method in which vanadium trioxide (V ₂ O ₃ ) acts as a reducing agent for vanadium pentoxide to obtain a vanadium electrolyte. The reducing agent method is easier than the electrochemical method. However, the reducing agent method must strictly control the exact purity and reaction rate of raw materials, and vanadium trioxide used as a reducing agent is expensive.

The third method is a catalytic reaction method. In the catalytic reaction method, a portion of tetravalent vanadium is reacted with a reducing agent such as formic acid in the presence of a catalyst to obtain a vanadium electrolyte. Since the catalytic reaction method can configure a very simple process, there is an advantage in that the investment cost for process equipment can be greatly reduced. Recently, research on a method of obtaining a vanadium electrolyte using a catalytic reaction method is in the spotlight.

Both Patent Document 1 and Non-Patent Document 1 introduce a catalytic reaction process for obtaining a vanadium electrolyte using a platinum catalyst (Pt/C) supported on a carbon support. In the case of applying such a catalyst, the catalyst component may be separated from the carbon support when the electrolyte solution flows towards the carbon support. As a result, the catalyst may be lost in the reaction process, and thus the quality of the product may be deteriorated. In addition, both Patent Literature 1 and Non-Patent Literature 1 only use a previously known catalyst reactor for producing a vanadium electrolyte, and the production rate of the vanadium electrolyte is not fast (about 60 L/hr).

Publication No. 10-2019-0102532

Catalytic production of impurity-free V3.5+ electrolyte for vanadium redox flow batteries, Nature Communications

An object of the present invention is to provide a reactor for preparing a vanadium electrolyte that does not require a catalyst support.

The present invention is to provide a reactor for preparing a vanadium electrolyte without loss of catalyst.

An object of the present invention is to provide a reactor for preparing a vanadium electrolyte capable of rapidly producing a vanadium electrolyte.

The object of the present invention is not limited to the above.

In order to solve the above problems, the reactor for preparing a vanadium electrolyte of the present invention includes a discharge unit for discharging a mixture including a reaction product of a tetravalent vanadium compound and a reducing agent and a solid catalyst; and a filtration unit located at a side of the discharge unit and including a plurality of pores to separate the solid catalyst.

The reactor for producing a vanadium electrolyte of the present invention does not require a catalyst support.

The reactor for producing a vanadium electrolyte of the present invention does not lose a catalyst.

The reactor for preparing a vanadium electrolyte of the present invention has a high vanadium production rate.

1 is a schematic diagram of a process for obtaining a vanadium electrolyte according to the prior art.
2 is a schematic diagram of a process for obtaining a vanadium electrolyte solution according to the present invention.

Hereinafter, the contents of the present application will be described in more detail.

The present invention relates to a reactor for preparing a vanadium electrolyte. That is, the present invention relates to a reactor, and is particularly suitable when applied to the production of a vanadium electrolyte. Here, the vanadium electrolyte solution includes a trivalent vanadium compound (V(III)) and a tetravalent vanadium compound (V(IV)), and a trivalent vanadium compound (V(III)) and a tetravalent vanadium compound (V(IV) )) is a mixed solution in a volume ratio of about 1:1. However, the above mixing ratio may be appropriately expanded in consideration of errors and the like. For example, the volume ratio (V(IV):V(III)) of the tetravalent vanadium compound (V(IV)) and the trivalent vanadium compound (V(III)) in the vanadium electrolyte is 4:6 to It can be within the 6:4 range. In other examples, the ratio may be in the range of 4.5:5.5 to 5.5:4.5, 4.9:5.1 to 5.1:4.9, or 4.99:5.01 to 5.01:4.99.

The reactor generally includes a raw material supply unit for supplying raw materials, a reaction unit for reacting reactants in the raw materials, and a discharge unit for discharging reaction products.

A reaction to which the reactor of the present invention is applied is a reaction that proceeds in the presence of a catalyst. Thus, the present invention is characterized in that, unlike the usual reactors, it comprises in particular an outlet and an additional part.

The reactor for preparing a vanadium electrolyte according to the present invention is characterized in that it includes a discharge unit and a filtering unit. 2 shows a schematic diagram of a vanadium electrolyte manufacturing process using the reactor of the present invention. The part shown in Figure 2 is the reactor of the present invention.

The discharge unit discharges a mixture including a reaction product of a tetravalent vanadium compound and a reducing agent and a solid catalyst. The filtration unit is located on the side of the discharge unit and includes a plurality of pores to separate the solid catalyst. As a result, the catalyst included in the mixture is filtered through the filtering unit, and only materials other than the catalyst, for example, a vanadium electrolyte, may flow out of the reactor.

A reaction product of the tetravalent vanadium compound and the reducing agent may correspond to the above-described vanadium electrolyte.

“Filtration unit” is a functional expression such as a sieve or filter that passes through a heterogeneous mixture, for example, a solid-liquid mixture, only permeates liquid substances and filters solid substances. The present invention applies to a reactor in which the filtration unit is located on the side of the discharge unit. Accordingly, when the material to be discharged is a heterogeneous mixture, the solid material may remain inside the reactor, and only the liquid or gaseous material may be discharged out of the reactor. Through this, it is possible to prevent the catalyst used in the reaction from leaking out to the outside. In addition, in this case, the catalyst support required to prevent aggregation of the catalyst is also unnecessary. Furthermore, since the reactor of the present invention can continuously use the catalyst (replacement process is unnecessary), the vanadium electrolyte as a product can be quickly obtained.

In this way, in the case of a reactor equipped with a discharge unit and a filtration unit, a catalyst support is unnecessary, catalyst loss can be eliminated, and products can be rapidly produced.

In one embodiment, the filtration unit may be present inside the reactor. Specifically, the filtration unit may be present inside the reactor so that the mixture including the reaction product and the catalyst may contact or contact pores of the filtration unit. That is, the reactor may be designed such that, in a reaction using the reactor of the present invention, a product of the reaction must pass through the filter before being discharged from the reactor. As a result, the catalyst separated from the filtration unit remains inside the reactor.

In addition, the filtration unit includes a plurality of pores, and these pores also function to separate the catalyst particles so that aggregation does not occur. Therefore, as the filtering unit is provided, the reaction catalyst using the reactor of the present invention does not require a structure functioning to prevent its aggregation. That is, the catalyst of the reaction using the reactor of the present invention may not require a catalyst support applied to prevent its aggregation or increase its specific surface area. If a normal catalyst includes a metal component that functions as such and a catalyst support supporting the metal component, the catalyst used in the present invention may not have the catalyst support. That is, the catalyst may be composed only of metal components.

In one embodiment, the catalyst may include a metal component as a component to have its function. The metal component may be a single metal, an intermetallic compound or an alloy. Platinum (Pt/C) supported on carbon is usually applied to the reduction reaction of the vanadium compound, but in the present invention, such a platinum-based component may be included as an active component of the catalyst.

In one embodiment, the catalyst may include an intermetallic compound of platinum and other metals (eg, transition metals). In FIG. 2, the corresponding catalyst is indicated as IMCC, and IMCC is an abbreviation of “Inter-Mettallic Compound Catalyst”. Here, the intermetallic compound means having a structure in which heterogeneous metal elements are arranged according to a predetermined rule, unlike an alloy. Whether or not the catalyst contains an intermetallic compound can be confirmed through crystal structure analysis (eg XRD) of the metal. In one embodiment, the catalyst may include FePt, FePt ₃ , CoPt, CoPt ₃ or a combination thereof.

As the catalyst, one having an appropriate size may be selected. In one embodiment, the size of the catalyst may be in the range of 5 μm to 50 μm. In another embodiment, the lower limit of the size of the catalyst may be 10 μm, 15 μm, 20 μm, 25 μm or 30 μm. In another embodiment, the upper limit of the catalyst size may be 45 μm or 40 μm. The size of the catalyst can be measured, for example, by a line scan function of EDS built into a high-resolution TEM.

As mentioned above, the filtration portion of the reactor includes a plurality of pores. In addition, since the catalyst should not pass through the filter, the size of the pores is smaller than that of the catalyst. In one embodiment, the average size of the pores may be in the range of 0.5 μm to 5 μm.

In another example, the average size of the pores may be 0.75 μm or more or 1 μm or more, and may be 4 μm or less, 3 μm or less, 2 μm or less, or 1 μm or less.

As described above, in the method of the present invention, since the reaction using the catalyst continuously occurs in one reactor and there is a filtration unit inside the reactor in which the reaction proceeds, once the catalyst is supplied, it is supplied in another reactor until the operation of the reactor is stopped. No additional supply is required unless there is a reason. That is, if the reactor of the present invention is used, the catalyst may be supplied only once.

In addition to the above elements, the reactor of the present invention may include other known essential components required for preparing a vanadium electrolyte, and even if a detailed description thereof is omitted, those skilled in the art will easily understand the reactor of the present invention.

The present invention, in another example, relates to a method for preparing a vanadium electrolyte solution. The method utilizes the reactor of the present invention.

In the present invention, a vanadium electrolyte is prepared using a reaction involving a catalyst. That is, the chemical reaction mainly used in the present invention is a reduction reaction in the presence of a catalyst of a tetravalent vanadium compound. Therefore, in the present invention, a reaction raw material is prepared, the raw material is supplied to the catalyst reactor, the supplied raw material is reacted in the reactor, and then the reaction product is discharged from the reactor (see FIG. 2).

The present invention at least, the raw material manufacturing step; raw material supply step; catalyst supply step; reaction step; and a product outflow step. Hereinafter, each step is described in more detail.

The present invention at least, the raw material manufacturing step; reaction step; and a product outflow step. Hereinafter, each step is described in more detail.

In the present invention, in the raw material preparation step, a raw material containing a tetravalent vanadium compound and a reducing agent for the tetravalent vanadium compound is prepared. Here, the reducing agent for a tetravalent vanadium compound, as the term implies, means a substance capable of reducing a tetravalent vanadium compound while oxidizing itself. Here, the raw material may mean a dissolved salt of the tetravalent vanadium compound.

In one embodiment, the reducing agent of the tetravalent vanadium compound may be at least one of formic acid, formaldehyde, methanol, oxalic acid and ammonium hydroxide. Preferably, the reducing agent for the tetravalent vanadium compound may be at least one of formic acid and oxalic acid. More preferably, the reducing agent for the tetravalent vanadium compound may be formic acid. Here, oxalic acid may be used as a reducing agent for vanadium pentoxide, which is a precursor of the tetravalent vanadium compound.

A method of obtaining the raw material is not particularly limited. In one embodiment, the raw material may be obtained by mixing a salt of the tetravalent vanadium compound, a reducing agent of the tetravalent vanadium compound, and an appropriate solvent.

In another embodiment, the raw material may be a reaction product of another mixture. That is, the raw material may be obtained by reacting another mixture. Specifically, the raw material is a reaction of a precursor mixture including vanadium pentoxide (V ₂ O ₅ ), a reducing agent (oxalic acid, C ₂ H ₂ O ₄ in FIG. 2 ), and an aqueous sulfuric acid solution (FIG. 2, Aq. H ₂ SO ₄ ). may be a product. That is, the step of preparing the raw material may be to obtain a reaction product of a precursor mixture including vanadium pentoxide, a reducing agent of vanadium pentoxide, and an aqueous solution of sulfuric acid.

Here, the reducing agent may be a reducing agent for a pentavalent vanadium compound generated when the vanadium pentoxide is dissolved. Also, the reducing agent may be the same as the reducing agent for the tetravalent vanadium compound, or may be different. Since the reaction products of the precursor mixture correspond to the raw materials but all react during the preparation process, the reducing agent may be different from the reducing agent of the tetravalent vanadium compound.

As described above, the present invention proceeds as a main reaction for the reduction of a tetravalent vanadium compound. Here, the tetravalent vanadium compound can also be obtained through another reaction, for example, a reduction reaction of the aforementioned pentavalent vanadium compound.

In one example, the reaction of obtaining the raw material, that is, the reaction of the precursor mixture including the pentavalent vanadium compound may be performed in a reactor different from a reactor in which the reaction of the raw material occurs. As will be described later, this is because the reaction of the raw materials proceeds in the presence of a catalyst. That is, after the precursor mixture is reacted in one reactor, its product may be supplied to another reactor where the reaction of the raw material takes place. In FIG. 2, the reactor in which the reaction of the precursor mixture takes place is indicated as “ Mixing ”. In FIG. 2, the reactor in which the raw material reaction occurs is indicated as “ Filtering ” (the reactor corresponds to the reactor of the present invention). A reaction for obtaining the raw material and a reaction for obtaining a target product by reacting the raw material may be performed in the same reactor. However, in this case, since the unreacted pentavalent vanadium compound precursor (eg, vanadium pentoxide) may interact with the catalyst in the reactor, the reaction to obtain the raw material proceeds in the absence of a catalyst, and then the reaction to react the raw material is restarted. Since the process is required, it is effective to proceed each reaction in a different reactor.

The method of the present invention includes a reaction step of preparing the raw material and then reacting it in a reactor. Specifically, in the method of the present invention, the raw material is reacted in the reactor in the presence of a catalyst to obtain a tetravalent vanadium compound (V(IV)) and the A product in which the volume ratio (V(IV):V(III)) of the trivalent vanadium compound (V(III)) is in the range of 4:6 to 6:4 is obtained. In the reaction step, specifically, a mixture containing a trivalent vanadium compound and a tetravalent vanadium compound is prepared by reacting a portion of the tetravalent vanadium compound with a reducing agent.

After being supplied to the reactor, the catalyst accelerates the reaction of the raw material in the reactor. At this time, the supply amount of the catalyst can also be appropriately adjusted. In one embodiment, the supply amount of the catalyst may be within the range of 1 mg to 10 mg per 1 mL of the raw material. If the catalyst content is high, the reaction rate is increased and the reaction time may be shortened, but too much catalyst is not economical. Therefore, it is good to appropriately adjust the supply amount of the catalyst in consideration of the reaction rate and process economy. In another embodiment, the lower limit of the catalyst feed amount may be 2 mg, 3 mg, 4 mg, 5 mg or 6 mg. In another embodiment, the upper limit of the catalyst feed amount may be 9 mg, 8 mg, 7 mg or 6 mg.

As described above, in the method of the present invention, since the reaction using the catalyst continuously occurs in one reactor and there is a filtration unit inside the reactor in which the reaction proceeds, once the catalyst is supplied, it is supplied in another reactor until the operation of the reactor is stopped. No additional supply is required unless there is a reason. That is, in one embodiment, the supply of the catalyst may be performed once.

In the present invention, in the product discharge step, the product is discharged from the reactor. In the step of discharging the product, the product passes through a filter inside the reactor. As a result, the product is filtered through the filtering unit included in the product, and only materials other than this, for example, a vanadium electrolyte, may flow out of the reactor.

In one embodiment, as the product discharge step proceeds so that the product passes through the filtration unit inside the reactor, the catalyst in the product may remain in the filtration unit inside the reactor. That is, the step of discharging the product may proceed so that the catalyst of the product remains in the filtration unit inside the reactor.

When the process described above is performed in the vanadium electrolyte preparation process, the catalytic reaction can proceed without a separate catalyst support, the catalyst does not disappear even after the reaction is completed, and the reaction can proceed quickly.

Hereinafter, the content of the present invention will be described with examples, but the following examples do not limit the content of the present invention. In addition, the process of the embodiment can be easily understood by referring to FIG. 2 .

[Example 1]

Vanadium pentoxide, a reducing agent (oxalic acid), and an aqueous sulfuric acid solution were supplied to a 1 L reactor in a weight ratio of 11:8:81 (vanadium pentoxide:reducing agent:sulfuric acid aqueous solution). The reactor was a Glass Reactor. The temperature of the reactor was maintained at 80° C. for 3 hours to prepare a tetravalent vanadium electrolyte.

Thereafter, a reactor having a volume of about 1 L, an inner wall of which is glass-lined, and a 1 μm PP Woven Filter manufactured by Sefar was installed therein was prepared. The filter is installed in a direction in which the fluid flowing through the reactor comes into contact with the filter.

10 mL of the above-prepared tetravalent vanadium electrolyte, 0.186 mL of formic acid, and 0.06 g of FePt without a catalyst support were added to the reactor.

The reaction in the reactor proceeded while maintaining the temperature of the reactor at about 80°C. The time at which the conversion rate of the tetravalent vanadium compound (%, the volume of the produced trivalent vanadium compound/the volume of the introduced tetravalent vanadium compound) reached 100% was measured. At about 1 minute after the start of the reaction, the conversion rate of the tetravalent vanadium compound reached 100%, and no catalyst was detected in the final product.

[Example 2]

The same procedure as in Example 1 was performed except that FePt ₃ without a catalyst support was used as a catalyst. At about 1 minute after the start of the reaction, the conversion rate of the tetravalent vanadium compound reached 100%, and no catalyst was detected in the final product.

[Example 3]

The same procedure as in Example 1 was performed except that CoPt without a catalyst support was used as a catalyst. At about 3 minutes after the start of the reaction, the conversion rate of the tetravalent vanadium compound reached 100%, and no catalyst was detected in the final product.

[Example 4]

The same procedure as in Example 1 was performed except that CoPt ₃ without a catalyst support was used as a catalyst. At about 3 minutes after the start of the reaction, the conversion rate of the tetravalent vanadium compound reached 100%, and no catalyst was detected in the final product.

Through this, it can be confirmed that when the vanadium electrolyte is prepared by the method of the present invention, a catalyst support is not required, the catalyst is not lost, and the vanadium electrolyte can be rapidly prepared.

Claims (5)

a discharge unit for discharging a mixture including a reaction product of a tetravalent vanadium compound and a reducing agent and a solid catalyst; and
A filtration unit located on the side of the discharge unit and including a plurality of pores to separate the solid catalyst;
A reactor for producing vanadium electrolyte. According to claim 1,
The catalyst separated from the filtration unit remains inside the reactor,
A reactor for producing vanadium electrolyte. According to claim 1,
The catalyst is without a catalyst support,
A reactor for producing vanadium electrolyte. According to claim 1,
The catalyst comprises FePt, FePt ₃ , CoPt, CoPt ₃ or a combination thereof,
A reactor for producing vanadium electrolyte. According to claim 1,
The average size of the pores is in the range of 0.5 μm to 5 μm,
A reactor for producing vanadium electrolyte.

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