Device for recovering electrolyte capacity of iron-chromium flow battery

Abstract

The utility model belongs to the technical field of flow batteries, and discloses a device for recovering the electrolyte capacity of an iron-chromium flow battery, which comprises two stages of reaction towers and a filter, the liquid outlet of the first stage of reaction tower is communicated with the liquid inlet of the second stage of reaction tower, and the liquid outlet of the second stage of reaction tower is communicated with the liquid inlet of the filter; a gas inlet of the second-stage reaction tower is used for inputting reducing gas, a gas outlet of the filter is sequentially communicated with a gas outlet of the second-stage reaction tower and a gas inlet of the first-stage reaction tower, and a gas outlet of the first-stage reaction tower is used for discharging waste gas outwards; or, the gas inlet of the first-stage reaction tower is used for inputting the reducing gas, the gas outlet of the first-stage reaction tower is communicated with the gas inlet of the second-stage reaction tower, the gas outlet of the filter is communicated with the liquid inlet of the first-stage reaction tower, and the gas outlet of the second-stage reaction tower is used for discharging the waste gas outwards. According to the utility model, the offline capacity recovery technology is adopted, the capacity recovery time can be shortened, and the operation of an energy storage system user is reduced.

Description

TECHNICAL FIELD

[0001] The utility model belongs to the technical field of liquid flow battery, especially relates to a device for recovering electrolyte capacity of iron-chromium liquid flow battery. BACKGROUND

[0002] In the operation of the iron-chromium liquid flow battery, the positive electrode is the oxidation-reduction process of iron ions in 2 / 3 valence, and the negative electrode is the oxidation-reduction reaction of chromium ions in 2 / 3 valence, and the standard potential of the negative electrode reaction is relatively low, which is -0.41 V. In this way, hydrogen gas will be precipitated at the negative electrode under the condition of charging and large overpotential. Since hydrogen evolution is an irreversible reaction, the trivalent iron ions at the positive electrode cannot be completely reduced to divalent iron ions during discharging, resulting in the accumulation of trivalent iron ions at the positive electrode and the inability of the trivalent iron ions to participate in the discharge. During the long-term operation of the battery, the chargeable divalent iron ions in the positive electrolyte gradually decrease, and the state of charge of the positive electrolyte and the negative electrolyte is not matched, which cannot discharge the charge, causing the phenomenon of battery capacity attenuation.

[0003] The existing battery capacity recovery technology is to jointly construct a rebalancing system and a main system, and to adopt a synchronous capacity recovery process route. However, the technical route has the following problems:

[0004] The project site is limited, and the current commonly used energy storage systems are mostly power stations and other power sites. The site environment and land are not chemical land, so the capacity recovery technology mostly adopts an electrochemical method such as electrolysis. This method needs to select a suitable reducing agent and a supporting process system for the electrolysis process. The electrolysis process consumes a large amount of electricity, which greatly interferes with the energy storage system and is unknown. UTILITY MODEL CONTENTS

[0005] In view of the above problems, the utility model provides a device for recovering electrolyte capacity of an iron-chromium liquid flow battery, which adopts the following technical scheme:

[0006] The device for recovering electrolyte capacity of the iron-chromium liquid flow battery comprises two-stage reaction towers and a filter. The liquid inlet of the first-stage reaction tower is used to input the electrolyte to be recovered. The liquid outlet of the first-stage reaction tower is in communication with the liquid inlet of the second-stage reaction tower. The liquid outlet of the second-stage reaction tower is in communication with the liquid inlet of the filter. The gas inlet of the filter is used to input inert gas.

[0007] The gas inlet of the second-stage reaction tower is used to input reducing gas. The gas outlet of the filter is in communication with the gas outlet of the second-stage reaction tower and the gas inlet of the first-stage reaction tower in sequence. The gas outlet of the first-stage reaction tower is used to discharge waste gas outward. Alternatively, the gas inlet of the first-stage reaction tower is used to input reducing gas. The gas outlet of the first-stage reaction tower is in communication with the gas inlet of the second-stage reaction tower. The gas outlet of the filter is in communication with the liquid inlet of the first-stage reaction tower. The gas outlet of the second-stage reaction tower is used to discharge waste gas outward.

[0008] Further, the two-stage reaction tower comprises a first-stage bubble tower and a second-stage bubble tower;

[0009] The bottom of the first-stage bubble tower and the second-stage bubble tower is provided with a liquid inlet, the top of the first-stage bubble tower and the second-stage bubble tower is provided with a gas outlet, the side of the first-stage bubble tower and the second-stage bubble tower above the liquid inlet is provided with a gas inlet, and the other side of the first-stage bubble tower and the second-stage bubble tower along the height direction is provided with a first liquid outlet and a second liquid outlet.

[0010] Further, the two-stage reaction tower comprises a first-stage bubble tower and a second-stage bubble tower;

[0011] The gas inlet of the second-stage bubble tower inputs a reducing gas, the first liquid outlet and the second liquid outlet of the first-stage bubble tower are communicated with the inlet of the first electrolyte pump, the outlet of the first electrolyte pump is communicated with the liquid inlet of the second-stage bubble tower, the first liquid outlet and the second liquid outlet of the second-stage bubble tower are communicated with the inlet of the second electrolyte pump, and the outlet of the second electrolyte pump is communicated with the liquid inlet of the filter.

[0012] Further, the first-stage bubble tower further comprises a first-stage gas distributor, and the second-stage bubble tower further comprises a second-stage gas distributor;

[0013] One end of the first-stage gas distributor is communicated with the gas outlet of the filter and the gas outlet of the second-stage bubble tower and located outside the first-stage bubble tower, the other end of the first-stage gas distributor penetrates the gas inlet of the first-stage bubble tower and extends to the inside of the first-stage bubble tower, one end of the second-stage gas distributor is located outside the second-stage bubble tower for inputting the reducing gas, and the other end of the second-stage gas distributor penetrates the gas inlet of the second-stage bubble tower and extends to the inside of the second-stage bubble tower.

[0014] Further, the outside of the first-stage bubble tower and the second-stage bubble tower is covered with a first heating and heat preservation layer, and the inside of the first-stage bubble tower and the second-stage bubble tower is provided with a first distribution partition plate at the middle position.

[0015] Further, the two-stage reaction tower comprises a first-stage bubble tower and a second-stage bubble tower;

[0016] The bottom of the first-stage bubble tower and the second-stage bubble tower is provided with a liquid inlet, the top of the first-stage bubble tower and the second-stage bubble tower is provided with a gas outlet, the side of the first-stage bubble tower and the second-stage bubble tower above the liquid inlet is provided with a gas inlet, and the other side of the first-stage bubble tower and the second-stage bubble tower along the height direction is provided with a first liquid outlet and a second liquid outlet.

[0017] Furthermore, it also includes a third electrolyte pump, a fourth electrolyte pump, and a fifth electrolyte pump;

[0018] The primary spray tower has an air inlet for inputting reducing gas, a third electrolyte pump has an inlet for inputting electrolyte to be restored, an outlet of the third electrolyte pump is connected to the inlet of the primary spray tower, an inlet of the fourth electrolyte pump is connected to the outlet of the primary spray tower, an outlet of the fourth electrolyte pump is connected to the inlet of the secondary spray tower, an inlet of the fifth electrolyte pump is connected to the outlet of the secondary spray tower, and an outlet of the fifth electrolyte pump is connected to the inlet of the filter.

[0019] Furthermore, both the primary spray tower and the secondary spray tower are covered with a second heating and insulation layer, and both the primary spray tower and the secondary spray tower are provided with a second distribution baffle in the middle position inside.

[0020] Furthermore, both the primary spray tower and the secondary spray tower are equipped with nozzles at the liquid inlet. The nozzles are conical, and their outer diameter gradually increases along the direction of electrolyte flow.

[0021] Furthermore, the outer diameter of the filter gradually increases along the height direction, the bottom of the filter is arc-shaped, the top of the filter is flat, the top of the filter is provided with an air inlet, an air outlet and a liquid inlet, the bottom of the filter is provided with a liquid outlet, and a filter membrane is provided inside the filter near the liquid outlet.

[0022] The beneficial effects of this utility model are:

[0023] 1. The device for restoring the electrolyte capacity of an iron-chromium redox flow battery of this invention can rapidly reduce the Fe in the electrolyte at room temperature through a two-stage reaction tower and filter. 3+ H is generated at the same time + The generated H + The amount and H caused by hydrogen evolution during charging and discharging + The loss amount is consistent; therefore, using hydrogen sulfide can effectively remove Fe. 3+ It reduces free acid in the electrolyte to its original concentration, effectively replenishing the H+ lost through hydrogen evolution. + This ensures the service life and charge / discharge efficiency of the electrolyte. Through exhaust gas emission, no new impurities are introduced into the entire electrolyte system, nor is the loss of active substances in the original electrolyte caused. It can completely restore the various components in the electrolyte to their original concentrations. It consumes some water and requires a high reaction temperature. After cooling the electrolyte, it can be directly replenished with ultrapure water through multiple cycles such as two-stage reaction towers, and the solution can be mixed evenly without chemical difficulties.

[0024] 2. The device for recovering the electrolyte capacity of the iron-chromium liquid flow battery has the offline capacity recovery technology, can shorten the capacity recovery time, reduces the operation of the energy storage system user, and reduces the risk of chemical accidents caused by the lack of chemical technology experience of the energy storage system user.

[0025] Other features and advantages of the present application will be set forth in the following description of the application, and in part will become apparent to those skilled in the art upon examination of the following or can be learned by practice of the application. The objects and other advantages of the application can be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings. BRIEF DESCRIPTION OF DRAWINGS

[0026] In order to more clearly illustrate the technical solutions of the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiment or prior art description. Obviously, the drawings in the following description are some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained without creative labor on the basis of these drawings.

[0027] Figure 1 A device structure diagram for recovering the electrolyte capacity of the iron-chromium liquid flow battery according to the first embodiment of the present application is shown.

[0028] Figure 2 A device structure diagram for recovering the electrolyte capacity of the iron-chromium liquid flow battery according to the second embodiment of the present application is shown.

[0029] In the figure: 1, two-stage reaction tower; 2, filter; 3, gas pipeline; 4, first electrolyte pump; 5, second electrolyte pump; 6, first-stage bubble tower; 7, second-stage bubble tower; 8, first gas distributor; 9, second gas distributor; 10, first heating insulation layer; 11, first distribution partition; 12, first pressure control valve; 13, second pressure control valve; 14, first check valve; 15, third electrolyte pump; 16, fourth electrolyte pump; 17, fifth electrolyte pump; 18, first-stage spray tower; 19, second-stage spray tower; 20, second heating insulation layer; 21, second distribution partition; 22, spray head; 23, third pressure control valve; 24, fourth pressure control valve; 25, second check valve; 26, electric control valve; 27, filter membrane. DETAILED DESCRIPTION

[0030] In order to make the purpose, technical scheme and advantages of the embodiments of the utility model clearer, the technical scheme in the embodiments of the utility model will be clearly and completely explained in combination with the drawings in the embodiments of the utility model below. Obviously, the described embodiments are part of the embodiments of the utility model, rather than all the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by those skilled in the art without creative labor belong to the protection scope of the utility model.

[0031] It should be noted that the terms "first", "second" and the like in the present application are used to distinguish similar objects, and do not necessarily have to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged under appropriate circumstances, so that the embodiments of the application described herein. In the present application, the terms "up", "down", "left", "right", "front", "back", "top", "bottom", "in", "out", "middle", "vertical", "horizontal", "lateral", "longitudinal" and the like indicate the orientation or positional relationship shown in the drawings.

[0032] The utility model provides a kind of device for recovering iron-chromium liquid flow battery electrolyte capacity, the capacity of iron-based liquid flow battery is recovered using reducing gas, the device of the utility model adopts offline capacity recovery technology, can shorten capacity recovery time, reduce the operation of energy storage system user, reduce the risk of chemical accident caused by energy storage system user without chemical engineering technical experience, provide convenience for owner and guarantee system safety.

[0033] As shown in Figure 1 A kind of device for recovering iron-chromium liquid flow battery electrolyte capacity, including two-stage reaction tower 1 and filter 2, wherein, the liquid inlet of first-stage reaction tower is used to input electrolyte to be recovered, the liquid outlet of first-stage reaction tower is communicated with the liquid inlet of second-stage reaction tower, the liquid outlet of second-stage reaction tower is communicated with the liquid inlet of filter 2, the gas inlet of filter 2 is used to input inert gas, the liquid outlet of filter 2 is used to discharge filtered electrolyte outward.

[0034] The gas inlet of second-stage reaction tower is used to input reducing gas, the gas outlet of filter 2 is communicated with the gas outlet of second-stage reaction tower, the gas inlet of first-stage reaction tower in sequence by gas pipeline 3, the gas outlet of first-stage reaction tower is used to discharge waste gas outward.

[0035] Or, as shown in Figure 2 The gas inlet of first-stage reaction tower is used to input reducing gas, the gas outlet of first-stage reaction tower is communicated with the gas inlet of second-stage reaction tower, the liquid inlet of filter 2 is communicated with the gas outlet of first-stage reaction tower by gas pipeline 3, the gas outlet of second-stage reaction tower is used to discharge waste gas outward.

[0036] For example, the device for recovering the electrolyte capacity of the iron-chromium flow battery further comprises a first electrolyte pump 4 and a second electrolyte pump 5, and the two-stage reaction tower 1 comprises a first-stage bubble column 6 and a second-stage bubble column 7.

[0037] The bottom of the first-stage bubble column 6 and the second-stage bubble column 7 is provided with a liquid inlet, and the top of the first-stage bubble column 6 and the second-stage bubble column 7 is provided with a gas outlet. The side of the first-stage bubble column 6 and the second-stage bubble column 7 above the liquid inlet is provided with a gas inlet, and the other side of the first-stage bubble column 6 and the second-stage bubble column 7 is provided with a first liquid outlet and a second liquid outlet along the height direction.

[0038] The liquid inlet of the first-stage bubble column 6 is used for inputting the electrolyte to be recovered, and the gas inlet of the second-stage bubble column 7 is used for inputting the reducing gas. The first liquid outlet and the second liquid outlet of the first-stage bubble column 6 are communicated with the inlet of the first electrolyte pump 4 through a pipeline, the outlet of the first electrolyte pump 4 is communicated with the liquid inlet of the second-stage bubble column 7, the first liquid outlet and the second liquid outlet of the second-stage bubble column 7 are communicated with the inlet of the second electrolyte pump 5 through a pipeline, and the outlet of the second electrolyte pump 5 is communicated with the liquid inlet of the filter 2.

[0039] For example, the first-stage bubble column 6 further comprises a first-stage gas distributor 8, and the second-stage bubble column 7 further comprises a second-stage gas distributor 9. One end of the first-stage gas distributor 8 is communicated with the gas outlet of the filter 2 and the gas outlet of the second-stage bubble column 7 and is located outside the first-stage bubble column 6, the other end of the first-stage gas distributor 8 penetrates the gas inlet of the first-stage bubble column 6 and extends to the inside of the first-stage bubble column 6, one end of the second-stage gas distributor 9 is located outside the second-stage bubble column 7 and is used for inputting the reducing gas, and the other end of the second-stage gas distributor 9 penetrates the gas inlet of the second-stage bubble column 7 and extends to the inside of the second-stage bubble column 7.

[0040] For example, the outside of the first-stage bubble column 6 and the second-stage bubble column 7 is covered with a first heating and heat preservation layer 10, and the electrolyte in the first-stage bubble column 6 and the second-stage bubble column 7 is heated and preserved by the first heating and heat preservation layer 10.

[0041] For example, a first distribution partition plate 11 is arranged at the middle position inside the first-stage bubble column 6 and the second-stage bubble column 7, so as to increase the gas-liquid contact area, reduce the back mixing, and improve the efficiency and performance of the reactor.

[0042] For example, the gas outlet of the first-stage bubble column 6 is provided with a first pressure control valve 12, the gas outlet of the second-stage bubble column 7 and the gas conveying pipeline 3 are provided with a second pressure control valve 13, and the gas conveying pipeline 3 is provided with a first check valve 14 between the second pressure control valve 13 and the gas outlet of the filter 2.

[0043] The process and principle of reducing the electrolyte by the first-stage bubble column 6 and the second-stage bubble column 7 of the device are as follows:

[0044] As shown in Figure 1 The electrolyte to be recovered first enters the first bubbling tower 6, and then enters the second bubbling tower 7 through the first electrolyte pump 4. The reducing gas enters the second bubbling tower 7 through the second gas distributor 9. After the reaction is completed, the reducing gas flows through the gas conveying pipeline 3 through the second pressure control valve 13, and then reacts with the electrolyte in the first bubbling tower 6 again through the first gas distributor 8.

[0045] The electrolyte in the second bubbling tower 7 is pumped into the filter 2 by the first electrolyte pump 4, and inert gas is also pumped in to purge and replace the reducing gas in the liquid. The gas is conveyed to the first bubbling tower 6 through the gas conveying pipeline, and the residual electrolyte is reduced again, and the reducing gas is also absorbed again. Finally, the residual gas is discharged as waste gas through the first pressure control valve 12, and the tail gas is treated.

[0046] In the first bubbling tower 6, the electrolyte is in an excess state, and more Fe 3+ can fully absorb the reducing gas, reducing the content of waste gas. When the electrolyte enters the second bubbling tower 7, the concentration of Fe 3+ is reduced. In this way, in the second bubbling tower 7, the reducing gas is in an excess state, and the excess reducing gas can fully reduce the residual Fe 3+ . The reduced electrolyte is filtered, and inert gas is used to replace the residual reducing gas in the electrolyte to avoid interference with the use of the electrolyte caused by residual hydrogen sulfide in the electrolyte.

[0047] The device of the embodiment has the following advantages: The two-stage bubbling tower reaction can reduce the electrolyte more deeply, and the hydrogen sulfide content in the tail gas is low because the hydrogen sulfide is fully absorbed as much as possible through the two-stage gas absorption. The filter 2 uses inert gas to promote the filtration of the electrolyte and disperse the residual hydrogen sulfide in the electrolyte. The trace amount of hydrogen sulfide in the residual gas is again absorbed by the electrolyte in the second bubbling tower 7 to achieve tail gas treatment and electrolyte reduction. The electrolyte first enters the first bubbling tower 6 and then enters the second bubbling tower 7, and the reducing gas first enters the second bubbling tower 7 and then enters the first bubbling tower 6, which can promote the reaction and improve the reaction efficiency, and reduce the residual of toxic gas in the tail gas.

[0048] For example, the device for recovering the electrolyte capacity of the iron-chromium liquid flow battery further includes a third electrolyte pump 15, a fourth electrolyte pump 16, and a fifth electrolyte pump 17. The two-stage reaction tower 1 includes a first spraying tower 18 and a second spraying tower 19.

[0049] The bottom of the first spray tower 18 and the second spray tower 19 is provided with an air inlet, the top of the first spray tower 18 and the second spray tower 19 is provided with a liquid inlet, one side of the first spray tower 18 and the second spray tower 19 below the liquid inlet is provided with an air outlet, and the other side of the first spray tower 18 and the second spray tower 19 above the air inlet is provided with a liquid outlet.

[0050] The air inlet of the first spray tower 18 is used for inputting the reducing gas, the inlet of the third electrolyte pump 15 is used for inputting the electrolyte to be recovered, the outlet of the third electrolyte pump 15 is communicated with the liquid inlet of the first spray tower 18, the inlet of the fourth electrolyte pump 16 is communicated with the liquid outlet of the first spray tower 18, the outlet of the fourth electrolyte pump 16 is communicated with the liquid inlet of the second spray tower 19, the inlet of the fifth electrolyte pump 17 is communicated with the liquid outlet of the second spray tower 19, and the outlet of the fifth electrolyte pump 17 is communicated with the liquid inlet of the filter 2.

[0051] For example, the first spray tower 18 and the second spray tower 19 are both coated with a second heating and heat preservation layer 20, and the electrolyte in the first spray tower 18 and the second spray tower 19 is heated and preserved by the second heating and heat preservation layer 20.

[0052] For example, the first spray tower 18 and the second spray tower 19 are both provided with a second distribution partition plate 21 at a middle position inside, so as to increase the gas-liquid contact area, reduce back mixing, and improve the efficiency and performance of the reactor.

[0053] For example, the first spray tower 18 and the second spray tower 19 are both provided with a spray head 22 at the liquid inlet inside, the spray head 22 is conical, and the outer diameter of the spray head 22 gradually increases along the electrolyte flow direction.

[0054] For example, the liquid inlet of the first spray tower 18 is provided with a third pressure control valve 23, and the liquid inlet of the second spray tower 19 is provided with a fourth pressure control valve 24.

[0055] For example, the gas conveying pipeline 3 is provided with a second check valve 25 between the liquid inlet of the first spray tower 18 and the air outlet of the filter 2, and an electric control valve 26 is arranged between the air outlet of the first spray tower 18 and the air inlet of the second spray tower 19.

[0056] The process and principle of reducing the electrolyte by the first spray tower 18 and the second spray tower 19 of the device are as follows:

[0057] As shown in Figure 2 The reducing gas enters the first spray tower 18, the electrolyte to be recovered is first introduced into the first spray tower 18 by the third electrolyte pump 15 to react with the reducing gas, and the residual gas in the first spray tower 18 is extruded and discharged into the second spray tower 19 by the liquid.

[0058] The electrolyte continues to enter the secondary spray tower 19 by the fourth electrolyte pump 16 to react with the remaining reducing gas. While the remaining gas in the tower reacts fully, it is squeezed and returned to the primary spray tower 18 for the next use.

[0059] Electrolyte is pumped into filter 2 by the fifth electrolyte pump 17, and inert gas is simultaneously introduced to purge the reducing gas in the liquid and replace the reducing gas in the liquid. At the same time, the gas is returned to the first-stage spray tower 18 for the next use, and the waste gas is discharged from the exhaust port of the second-stage spray tower 19.

[0060] The advantages of this device are: the two-stage spray tower reaction allows for a deeper reduction of the electrolyte; the two-stage gas absorption allows for the full absorption of reducing gases, resulting in less toxic exhaust gas; the use of inert gas in filter 2 promotes electrolyte filtration and disperses residual reducing gases in the electrolyte, allowing trace amounts of residual gas to pass through the spray tower again for use in the next electrolyte reduction absorption, thus achieving exhaust gas treatment and electrolyte reduction; the electrolyte first enters the first-stage spray tower 18 and then the second-stage spray tower 19, while the reducing gases first enter the first-stage spray tower 18 and then the second-stage spray tower 19, before returning to the first-stage spray tower, which promotes the reaction, improves reaction efficiency, and reduces the residue of toxic gases in the exhaust gas.

[0061] The aforementioned gases include, but are not limited to: hydrogen sulfide, carbon monoxide, hydrogen, methane, etc.

[0062] For example, the outer diameter of filter 2 gradually increases along the height direction, the bottom of filter 2 is arc-shaped, the top of filter 2 is flat, the top of filter 2 is provided with an air inlet, an air outlet and a liquid inlet, the bottom of filter 2 is provided with a liquid outlet, and a filter membrane 27 is provided inside filter 2 near the liquid outlet.

[0063] This invention relates to a device for restoring the capacity of the electrolyte in an iron-chromium redox flow battery, which can rapidly reduce the Fe content in the electrolyte at room temperature. 3+ H is generated at the same time + The generated H + The amount and H caused by hydrogen evolution during charging and discharging + The loss amount is consistent; therefore, using hydrogen sulfide can effectively remove Fe. 3+ It reduces free acid in the electrolyte to its original concentration, effectively replenishing the H+ lost through hydrogen evolution. + This ensures the service life and charge / discharge efficiency of the electrolyte. Through exhaust gas emission, no new impurities are introduced into the entire electrolyte system, nor is the loss of active substances in the original electrolyte caused. It can completely restore the various components in the electrolyte to their original concentrations. It consumes some water and requires a high reaction temperature. After cooling the electrolyte, ultrapure water can be directly added during multiple cycles through bubble towers or spray towers, and the solution can be mixed evenly without any chemical difficulties.

[0064] Although the utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that the technical solutions recorded in the foregoing embodiments can still be modified, or some technical features therein can be replaced equivalently, and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the utility model.

Claims

1. An apparatus for recovering capacity of an iron-chromium flow battery electrolyte, the apparatus comprising: The two-stage reaction tower (1) and the filter (2) are included, wherein the liquid inlet of the first-stage reaction tower is used for inputting the electrolyte to be recovered, the liquid outlet of the first-stage reaction tower is communicated with the liquid inlet of the second-stage reaction tower, the liquid outlet of the second-stage reaction tower is communicated with the liquid inlet of the filter (2), and the gas inlet of the filter (2) is used for inputting the inert gas; The gas inlet of the second-stage reaction tower is used for inputting the reducing gas, the gas outlet of the filter (2) is sequentially communicated with the gas outlet of the second-stage reaction tower and the gas inlet of the first-stage reaction tower, the gas outlet of the first-stage reaction tower is used for discharging the waste gas, or the gas inlet of the first-stage reaction tower is used for inputting the reducing gas, the gas outlet of the first-stage reaction tower is communicated with the gas inlet of the second-stage reaction tower, the gas outlet of the filter (2) is communicated with the liquid inlet of the first-stage reaction tower, and the gas outlet of the second-stage reaction tower is used for discharging the waste gas.

2. The apparatus for recovering electrolyte capacity of an iron-chromium flow battery of claim 1, wherein, The two-stage reaction tower (1) includes a first-stage bubble tower (6) and a second-stage bubble tower (7); The bottom of the first-stage bubble tower (6) and the second-stage bubble tower (7) is provided with a liquid inlet, the top of the first-stage bubble tower (6) and the second-stage bubble tower (7) is provided with a gas outlet, one side of the first-stage bubble tower (6) and the second-stage bubble tower (7) is provided with a gas inlet above the liquid inlet, and the other side of the first-stage bubble tower (6) and the second-stage bubble tower (7) is provided with a first liquid outlet and a second liquid outlet along the height direction.

3. The apparatus for recovering iron-chromium flow battery electrolyte capacity of claim 2, wherein, The first electrolyte pump (4) and the second electrolyte pump (5) are further included; The gas inlet of the second-stage bubble tower (7) inputs the reducing gas, the first liquid outlet and the second liquid outlet of the first-stage bubble tower (6) are communicated with the inlet of the first electrolyte pump (4), the outlet of the first electrolyte pump (4) is communicated with the liquid inlet of the second-stage bubble tower (7), the first liquid outlet and the second liquid outlet of the second-stage bubble tower (7) are communicated with the inlet of the second electrolyte pump (5), and the outlet of the second electrolyte pump (5) is communicated with the liquid inlet of the filter (2).

4. The apparatus for recovering the electrolyte capacity of an iron-chromium flow battery of claim 2, wherein, The first-stage bubble tower (6) further includes a first-stage gas distributor (8), and the second-stage bubble tower (7) further includes a second-stage gas distributor (9); One end of the first-stage gas distributor (8) is communicated with the gas outlet of the filter (2) and the gas outlet of the second-stage bubble tower (7) and is located outside the first-stage bubble tower (6), the other end of the first-stage gas distributor (8) penetrates the gas inlet of the first-stage bubble tower (6) and extends to the inside of the first-stage bubble tower (6), one end of the second-stage gas distributor (9) is located outside the second-stage bubble tower (7) and is used for inputting the reducing gas, and the other end of the second-stage gas distributor (9) penetrates the gas inlet of the second-stage bubble tower (7) and extends to the inside of the second-stage bubble tower (7).

5. The apparatus for recovering electrolyte capacity of an iron-chromium flow battery of any of claims 2-4, wherein, The outer part of the first-stage bubble column (6) and the second-stage bubble column (7) is covered with a first heating and heat-insulating layer (10), and a first distribution baffle (11) is arranged at the middle part of the interior of the first-stage bubble column (6) and the second-stage bubble column (7).

6. The apparatus for recovering iron-chromium flow battery electrolyte capacity of claim 1, wherein, The two-stage reaction tower (1) comprises a first-stage spray tower (18) and a second-stage spray tower (19); The bottom of the first-stage spray tower (18) and the second-stage spray tower (19) is provided with an air inlet, the top of the first-stage spray tower (18) and the second-stage spray tower (19) is provided with a liquid inlet, one side of the first-stage spray tower (18) and the second-stage spray tower (19) below the liquid inlet is provided with an air outlet, and the other side of the first-stage spray tower (18) and the second-stage spray tower (19) above the air inlet is provided with a liquid outlet.

7. The apparatus for recovering iron-chromium flow battery electrolyte capacity of claim 6, wherein, The two-stage reaction tower (1) further comprises a third electrolyte pump (15), a fourth electrolyte pump (16) and a fifth electrolyte pump (17). The air inlet of the first-stage spray tower (18) is used for inputting a reducing gas, the inlet of the third electrolyte pump (15) is used for inputting electrolyte to be recovered, the outlet of the third electrolyte pump (15) is communicated with the liquid inlet of the first-stage spray tower (18), the inlet of the fourth electrolyte pump (16) is communicated with the liquid outlet of the first-stage spray tower (18), the outlet of the fourth electrolyte pump (16) is communicated with the liquid inlet of the second-stage spray tower (19), the inlet of the fifth electrolyte pump (17) is communicated with the liquid outlet of the second-stage spray tower (19), and the outlet of the fifth electrolyte pump (17) is communicated with the liquid inlet of the filter (2).

8. The apparatus for recovering the electrolyte capacity of an iron-chromium flow battery of claim 6, wherein, The outer part of the first-stage spray tower (18) and the second-stage spray tower (19) is covered with a second heating and heat-insulating layer (20), and a second distribution baffle (21) is arranged at the middle part of the interior of the first-stage spray tower (18) and the second-stage spray tower (19).

9. The apparatus for recovering electrolyte capacity of an iron-chromium flow battery of any of claims 6-8, wherein, The interior of the first-stage spray tower (18) and the second-stage spray tower (19) is provided with a spray head (22) at the liquid inlet, the spray head (22) is conical, and the outer diameter of the spray head (22) gradually increases along the flow direction of the electrolyte.

10. The apparatus for recovering electrolyte capacity of an iron-chromium flow battery of claim 1 or 6, wherein, The filter (2) gradually increases in outer diameter along the height direction, the bottom of the filter (2) is arc-shaped, the top of the filter (2) is planar, the top of the filter (2) is provided with an air inlet, an air outlet and a liquid inlet, the bottom of the filter (2) is provided with a liquid outlet, and a filter membrane (27) is arranged at the liquid outlet in the interior of the filter (2).

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