Hydroiodic acid production apparatus and method

Abstract

The application relates to a hydriodic acid preparation device and method, and relates to the new energy technical field.The hydriodic acid preparation device comprises a first phosphoric acid circulating device, a second phosphoric acid circulating device, a hydriodic acid circulating device, a deiodine ion device and a membrane group, the membrane group comprises a first phosphoric acid chamber, a second phosphoric acid chamber and a hydriodic acid chamber which are sequentially arranged and are in fluid communication.The second phosphoric acid chamber is communicated with the deiodine ion device, so that even if a small amount of iodine ions enter the second phosphoric acid chamber, the iodine ions can enter the deiodine ion device for deiodine treatment along with the circulation of the liquid, and the liquid after the deiodine treatment is returned to the membrane group again for circulation, at this time, the iodine ions contained in the circulating liquid do not exceed the standard, and the migration of the iodine ions from the second phosphoric acid chamber to the first phosphoric acid chamber is avoided, so that the damage of the anode membrane caused by the migration of the iodine ions is avoided, and therefore the service life and the production efficiency of the membrane group can be greatly improved.

Description

Technical Field

[0001] This invention relates to the field of new energy technology, and particularly to an apparatus and method for preparing hydroiodic acid, especially an apparatus and method for preparing iodine battery raw materials. Background Technology

[0002] Hydroiodic acid is a widely used raw material in industry, especially an important raw material for iodine batteries. Existing equipment for producing hydroiodic acid, such as a two-chamber membrane module, uses a single cation exchange membrane for both the anode and cathode chambers. Hydroiodic acid is obtained by oxidation and reduction reactions occurring in the anode and cathode chambers, respectively. However, in actual production, it has been found that the cation exchange membrane's lifespan is far shorter than expected, requiring frequent production interruptions to replace it, resulting in a significant drop in production capacity and high production costs. Summary of the Invention

[0003] The present invention provides an apparatus and method for preparing hydroiodic acid, which is used to solve at least one of the above-mentioned technical problems.

[0004] According to a first aspect of the present invention, the present invention provides a hydroiodic acid preparation apparatus, comprising: a first phosphoric acid circulation device, a second phosphoric acid circulation device, a hydroiodic acid circulation device, an iodine removal device, and a membrane assembly, wherein the membrane assembly comprises a first phosphoric acid chamber, a second phosphoric acid chamber, and a hydroiodic acid chamber arranged sequentially and in fluid communication.

[0005] The first phosphoric acid chamber is connected to the first phosphoric acid circulation device to form a circulation system, so that the liquid circulates between the first phosphoric acid chamber and the first phosphoric acid circulation device.

[0006] The second phosphoric acid chamber is connected to the deiodination ionization device, and the liquid in the deiodination ionization device flows into the second phosphoric acid circulation device after deiodination;

[0007] The hydroiodic acid chamber is connected to the hydroiodic acid circulation device, so that the liquid circulates between the hydroiodic acid chamber and the hydroiodic acid circulation device.

[0008] In one embodiment, the membrane assembly includes an anode membrane and a cation membrane, the space between the anode membrane and the cation membrane defining a second phosphate chamber, wherein the concentration of iodide ions permeating from the hydroiodic acid chamber through the cation membrane in the liquid within the second phosphate chamber is less than 0.05%.

[0009] In one embodiment, a second phosphate chamber partition is disposed between the anode membrane and the cation membrane. The second phosphate chamber partition has a plurality of second phosphate chamber partition channels. Liquid in the second phosphate chamber can flow into the deiodination ion device through the plurality of second phosphate chamber partition channels respectively, and liquid in the second phosphate circulation device can flow into the second phosphate chamber through the second phosphate chamber partition channels.

[0010] In one embodiment, the membrane assembly further includes an anode plate, an anode plate, and an anode chamber partition, each having an anode end plate flow channel, arranged sequentially. The anode end plate is located on the side of the anode membrane away from the cation exchange membrane, and the anode end plate is located on the side of the anode plate away from the anode chamber partition. The space between the anode end plate, the anode plate, the anode chamber partition, and the anode membrane defines a first phosphoric acid chamber, in which the reaction is: O 2- -2e = O2, 2H2O = 2OH- - +2H + =O2 + 2H + .

[0011] In one embodiment, the membrane assembly further includes a cathode plate and a cathode plate having cathode end plate channels, the cathode plate being located on the side of the cation membrane away from the anolyte membrane, and the cathode end plate being located on the side of the cathode plate away from the cation membrane. The space between the cation membrane, the cathode plate, and the cathode end plate defines the hydroiodic acid chamber, in which the reaction is: I + e = I - I - +H + =HI.

[0012] In one embodiment, an anion chamber partition is disposed between the cation membrane and the cathode plate, and the membrane assembly further includes gaskets located between the anode end plate and the anode plate, between the anode plate and the anode membrane, between the anode membrane and the second phosphate chamber partition, between the second phosphate chamber partition and the cation membrane, between the cation membrane and the anion chamber partition, between the anion chamber partition and the cathode plate, and between the cathode plate and the cathode end plate.

[0013] In one embodiment, the anode plate is provided with a plurality of anode plate side flow channels, a plurality of anode plate upper flow channels and a plurality of anode plate lower flow channels, the anode plate is provided with a plurality of anode plate flow channels, and the anode chamber partition is provided with a plurality of anode chamber partition flow channels.

[0014] The anode end plate, the anode plate, the anode chamber partition, and the second phosphate chamber partition are fluidly connected through flow channels thereon, so that the liquid in the second phosphate chamber can flow into the deiodination ion device through multiple anode chamber partition flow channels, multiple second phosphate chamber partition flow channels, multiple anode plate flow channels, and multiple upper anode end plate flow channels respectively. Furthermore, the liquid after deiodination by the deiodination ion device can flow into the second phosphate chamber through multiple lower anode end plate flow channels, multiple anode plate flow channels, multiple anode chamber partition flow channels, and multiple second phosphate chamber partition flow channels.

[0015] In one embodiment, the deiodination ionization device includes:

[0016] An iodine removal circulation tank, the inlet of which is connected to the second phosphate chamber;

[0017] A ceramic membrane iodine separation device, wherein the inlet of the ceramic membrane iodine separation device is connected to the outlet of the iodine removal circulation tank, and the outlet of the ceramic membrane iodine separation device is connected to the inlet of the second phosphoric acid circulation device, the ceramic membrane iodine separation device being used to separate elemental iodine from the liquid and input the liquid after solid-liquid separation into the second phosphoric acid circulation device; and

[0018] A dosing device is connected to the pipeline between the inlet of the ceramic membrane iodine separation device and the outlet of the iodine removal circulation tank.

[0019] In one embodiment, the dosing device includes a metering tank and a metering pump connected to the metering tank. The metering tank contains hydrogen peroxide, and the metering pump is capable of adding the hydrogen peroxide from the metering tank to the ceramic membrane iodine separation device.

[0020] This invention also provides a method for preparing hydroiodic acid, comprising the following steps:

[0021] A cation exchange membrane is placed between the anode membrane and the cathode plate of the membrane module;

[0022] The second phosphoric acid chamber defined between the anode membrane and the cation membrane is connected to the deiodide ionization device, so that the liquid in the second phosphoric acid chamber flows into the deiodide ionization device;

[0023] The liquid in the deiodination ionization device undergoes solid-liquid separation to remove elemental iodine from the liquid, and the deiodinated liquid flows into the second phosphoric acid circulation device.

[0024] The liquid in the hydroiodic acid chamber of the membrane module circulates between the hydroiodic acid chamber and the hydroiodic acid circulation device.

[0025] Compared with the prior art, the advantages of the present invention are as follows: the second phosphoric acid chamber is connected to the deiodination ion device, so even if a small amount of iodide ions enter the second phosphoric acid chamber, they will enter the deiodination ion device for deiodination treatment along with the liquid circulation. The deiodinated liquid is then returned to the membrane module for recycling. At this time, the iodide ion content in the circulating liquid will not exceed the standard, and will not cause iodide ions in the second phosphoric acid chamber to migrate to the first phosphoric acid chamber. This ensures that the anode membrane will not be damaged due to the migration of iodide ions, thus greatly improving the service life of the membrane module.

[0026] Furthermore, experiments have shown that when the concentration of iodide ions in the liquid of the second phosphate chamber is less than 0.05%, the transfer of iodide ions from the liquid of the second phosphate chamber to the cation chamber will not occur. This avoids damage to the anolyte caused by the oxidization of iodide ions on the side of the anolyte near the cation chamber during the transfer of iodide ions to the first phosphate chamber (i.e., the cation chamber). Attached Figure Description

[0027] The invention will now be described in more detail with reference to embodiments and the accompanying drawings.

[0028] Figure 1 This is a schematic diagram of the hydroiodic acid preparation apparatus in an embodiment of the present invention;

[0029] Figure 2 This is a schematic diagram of the membrane module in an embodiment of the present invention;

[0030] Figure 3 This is a schematic diagram of the membrane module structure in an embodiment of the present invention, in which the gasket, cation chamber partition, second phosphate chamber partition, and anion chamber partition are not shown.

[0031] Figure 4 , Figure 5 and Figure 6 These are, respectively, the front view, side view, and top view of the anode plate in an embodiment of the present invention;

[0032] Figure 7 This is a schematic diagram of the anode plate structure in an embodiment of the present invention;

[0033] Figure 8 This is a schematic diagram of the cathode plate structure in an embodiment of the present invention;

[0034] Figure 9 This is a schematic diagram of the structure of the second phosphate chamber partition in an embodiment of the present invention;

[0035] Figure 10a This is a schematic diagram of the anode membrane structure in an embodiment of the present invention;

[0036] Figure 10b This is a schematic diagram of the structure of the septum partition in an embodiment of the present invention;

[0037] Figure 11 This is a schematic diagram of the structure of the vaginal diaphragm in an embodiment of the present invention;

[0038] Figure 12 and Figure 13 These are the front view and side view of the cathode end plate in an embodiment of the present invention.

[0039] Figure label:

[0040] 1. First phosphoric acid cycle unit; 2. Second phosphoric acid cycle unit; 3. Hydroiodic acid cycle unit; 4. Iodide removal unit; 5. Membrane module; 6. Power supply;

[0041] 11. First phosphoric acid circulation tank; 12. First phosphoric acid circulation pump;

[0042] 21. Second phosphoric acid circulation tank; 22. Second phosphoric acid circulation pump;

[0043] 31. Hydroiodic acid circulation tank; 32. Hydroiodic acid circulation pump;

[0044] 41. Ceramic membrane iodine separation device; 42. Iodine removal circulation tank; 43. Dosing device; 44. Iodine removal circulation pump;

[0045] 431. Metering box; 432. Metering pump;

[0046] 501. Primary phosphate chamber; 502. Secondary phosphate chamber; 503. Hydroiodic acid chamber;

[0047] 51. Anode end plate; 511. Side flow channel of anode end plate; 512. Upper flow channel of anode end plate; 513. Lower flow channel of anode end plate;

[0048] 52. Anode plate; 521. Anode plate connecting lug; 522. Anode plate flow channel;

[0049] 50. Cavity partition; 5001. Cavity partition flow channel;

[0050] 53. Anode membrane; 531. Anode membrane flow channel;

[0051] 54. Second phosphate chamber partition; 541. Second phosphate chamber partition flow channel;

[0052] 55. Cation membrane; 56. Anion chamber partition;

[0053] 57. Cathode plate; 571. Cathode plate connecting lug;

[0054] 58. Cathode end plate; 581. Cathode end plate flow channel;

[0055] 59. Gasket. Detailed Implementation

[0056] The invention will now be further described with reference to the accompanying drawings.

[0057] In the production of hydroiodic acid, an important raw material for iodine batteries, the existing one-membrane-two-chamber membrane module structure has a cation membrane whose service life is far from the expected life. Production needs to be interrupted many times to replace the cation membrane, resulting in a serious drop in production capacity and high production costs.

[0058] To address this phenomenon, this invention creatively discovers that the anode and cathode chambers share a single cation exchange membrane. Since the cation exchange membrane allows cations to pass through while blocking anions, theoretically, iodide ions should not migrate from the cathode chamber to the anode chamber through the cation exchange membrane. However, in practice, it has been found that when the concentration of iodide ions in the liquid is high, for example, when the concentration of iodide ions in the hydroiodic acid in the membrane assembly reaches 10% or higher, a small amount of iodide ions (I...) will be present. - Iodine ions migrate from the cathode chamber through the cation membrane to the anode chamber (the higher the concentration, the higher the migration rate of iodine ions). During this migration, some iodine ions enter the cation membrane and reach the side of the membrane closest to the anode chamber. Due to the oxidizing effect of the anode chamber on this area, some of the iodine ions that did not have time to pass through the cation membrane are oxidized. The oxidized iodine ions form elemental iodine. Since elemental iodine is an oxidizing solid, its accumulation inside the cation membrane can cause problems such as blistering and bulging, which seriously affects the lifespan of the cation membrane. Furthermore, the iodine ions that pass through the cation membrane and enter the anode chamber are oxidized to form elemental iodine. Most of the elemental iodine adheres to the surface of the cation membrane, causing a decrease in the conductivity of the cation membrane, affecting production efficiency, and also greatly affecting the lifespan of the cation membrane.

[0059] In other words, based on the phenomenon that the lifespan of the cation membrane in actual production is far from the expected value, this invention creatively discovered the technical problem that causes this phenomenon: a small number of anions can enter the interior of the cation membrane and / or penetrate the cation membrane and be oxidized into elemental solids. The accumulation of these elemental solids inside the cation membrane leads to problems such as blistering and bulging, thereby reducing the lifespan of the cation membrane.

[0060] Furthermore, in order to solve the technical problem of reduced lifespan of the cation membrane due to blistering and bulging during the production of raw materials for iodine batteries, the present invention provides a hydroiodic acid preparation apparatus.

[0061] like Figures 1-13 As shown, a hydroiodic acid preparation apparatus of the present invention includes a first phosphoric acid circulation device 1, a second phosphoric acid circulation device 2, a hydroiodic acid circulation device 3, an iodine removal device 4, and a membrane assembly 5. The membrane assembly 5 includes a first phosphoric acid chamber 501, a second phosphoric acid chamber 502, and a hydroiodic acid chamber 503 arranged in sequence and in fluid communication.

[0062] The electrolyte in the hydroiodic acid preparation apparatus of this invention is phosphoric acid, specifically, the liquid circulating between the first phosphoric acid chamber 501 and the second phosphoric acid chamber 502 is phosphoric acid. Phosphoric acid is used as the electrolyte because when other acids, such as sulfuric acid, are used, the sulfate ions are easily reduced to elemental sulfur after the sulfuric acid passes through the cation exchange membrane into the anion chamber. If elemental sulfur volatilizes into the system during the subsequent hydroiodic acid purification and concentration process, it will affect the evaporation, concentration, and product purity. Therefore, this invention uses phosphoric acid as the electrolyte. Although some hydroiodic acid may still pass through the cation exchange membrane into the anion chamber, the phosphate ions are generally not reduced, thus avoiding the problem of elemental sulfur contamination in the hydroiodic acid. Furthermore, even if phosphate ions are reduced to phosphorous acid, it can be used to prevent oxidation during the subsequent hydroiodic acid concentration and purification process; therefore, phosphorous acid will not affect the subsequent hydroiodic acid concentration and purification.

[0063] like Figure 1 As shown, the first phosphoric acid circulation device 1 includes a first phosphoric acid circulation tank 11 and a first phosphoric acid circulation pump 12. The liquid outlet of the first phosphoric acid chamber 501 is connected to the inlet of the first phosphoric acid circulation tank 11. The outlet of the first phosphoric acid circulation tank 11 is connected to the first phosphoric acid chamber 501 through the first phosphoric acid circulation pump 12, so that the liquid (phosphoric acid) circulates between the first phosphoric acid chamber 501 and the first phosphoric acid circulation device 1.

[0064] In addition, the first phosphoric acid circulation tank 11 is also equipped with a liquid filling port, through which phosphoric acid can be added to the first phosphoric acid circulation tank 11.

[0065] The second phosphoric acid chamber 502 is connected to the deiodination ion device 4, so that the liquid in the second phosphoric acid chamber 502 flows into the deiodination ion device 4; the deiodination ion device 4 is connected to the second phosphoric acid circulation device 2, so that the liquid in the deiodination ion device 4 flows into the second phosphoric acid circulation device 2 after deiodination.

[0066] The deiodine ion removal device 4 includes a deiodine circulation tank 42, a ceramic membrane iodine separation device 41, and a dosing device 43. The inlet of the deiodine circulation tank 42 is connected to the second phosphoric acid chamber 502, so that the liquid in the second phosphoric acid chamber 502 flows into the deiodine circulation tank 42.

[0067] The inlet of the ceramic membrane iodine separation device 41 is connected to the outlet of the deiodine circulation tank 42 via the deiodine circulation pump 44. The outlet of the ceramic membrane iodine separation device 41 is connected to the inlet of the second phosphoric acid circulation device 2. The ceramic membrane iodine separation device 41 is used to separate elemental iodine from the liquid and input the liquid after solid-liquid separation into the second phosphoric acid circulation device 2.

[0068] The second phosphoric acid circulation device 2 includes a second phosphoric acid circulation tank 21 and a second phosphoric acid circulation pump 22. The outlet of the ceramic membrane iodine separation device 41 is connected to the liquid inlet of the second phosphoric acid circulation tank 21. Therefore, the ceramic membrane iodine separation device 41 inputs the liquid after solid-liquid separation into the second phosphoric acid circulation tank 21. The liquid outlet of the second phosphoric acid circulation tank 21 is connected to the second phosphoric acid chamber 502 through the second phosphoric acid circulation pump 22. The second phosphoric acid circulation pump 22 can transport the liquid in the second phosphoric acid circulation tank 21 that does not contain elemental iodine (solid) to the second phosphoric acid chamber 502.

[0069] The dosing device 43 is connected to the pipeline between the inlet of the ceramic membrane iodine separation device 41 and the outlet of the deiodination circulation tank 42. The dosing device 43 includes a metering tank 431 and a metering pump 432 connected to the metering tank 431. The metering tank 431 contains hydrogen peroxide, and the metering pump 432 adds the hydrogen peroxide from the metering tank 431 to the ceramic membrane iodine separation device 41. Since the liquid in the deiodination circulation tank 42 originates from the second phosphoric acid chamber 502 and contains elemental iodine (solid), adding hydrogen peroxide to the ceramic membrane iodine separation device 41 through the metering tank 431 oxidizes iodide ions to elemental iodine under acidic conditions, thereby achieving solid-liquid separation. The separated liquid is free of elemental iodine and can be returned to the second phosphoric acid circulation device 2.

[0070] Ceramic membranes can be, for example, acid- and alkali-resistant and oxidation-resistant separation membranes.

[0071] The hydroiodic acid chamber 503 is cyclically connected to the hydroiodic acid circulation device 3, so that the liquid circulates between the hydroiodic acid chamber 503 and the hydroiodic acid circulation device 3.

[0072] Membrane module 5 includes an anolyte 53 and a cation exchange membrane 55, with the space between the anolyte 53 and the cation exchange membrane 55 defining a second phosphate chamber 502. Since the anolyte 53 is located in the first phosphate chamber 501, which is the cation chamber where the oxidation reaction occurs, the anolyte 53 is configured to have higher antioxidant properties than the cation exchange membrane 55.

[0073] Furthermore, a second phosphoric acid chamber partition 54 with flow channels is disposed between the anolyte 53 and the cation exchange 55, such as... Figure 9 As shown, the second phosphoric acid chamber partition 54 with flow channels is provided with multiple second phosphoric acid chamber partition flow channels 541. The liquid in the second phosphoric acid chamber 502 can flow into the deiodide ion device 4 through the multiple second phosphoric acid chamber partition flow channels 541 respectively, and the liquid in the second phosphoric acid circulation device 2 can flow into the second phosphoric acid chamber 502 through the second phosphoric acid chamber partition flow channels 541.

[0074] like Figure 4 , Figure 5 and Figure 6As shown, the membrane assembly 5 also includes an anode plate 51, an anode plate 52, and an anode chamber partition 50, which are arranged sequentially with anode end plate channels. The anode chamber partition 50 is located on the side of the anode membrane 53 away from the cation membrane 55, and the anode plate 51 is located on the side of the anode plate 52 away from the anode chamber partition 50. The space between the anode plate 51, the anode plate 52, the anode chamber partition 50, and the anode membrane 53 defines a first phosphoric acid chamber 501. The reaction formula in the first phosphoric acid chamber 501 is: O 2- -2e = O2, 2H2O = 2OH- - +2H + =O2 + 2H + .

[0075] like Figure 12 and Figure 13 As shown, the membrane module 5 also includes a cathode plate 58 with a cathode end plate flow channel 581 and a cathode plate 57. The cathode plate 57 is located on the side of the cation membrane 55 away from the anode membrane 53, and the cathode end plate 58 is located on the side of the cathode plate 57 away from the cation membrane 55. An anion chamber partition 56 is disposed between the cation membrane 55 and the cathode plate 57. The space between the cation membrane 55, the anion chamber partition 56, the cathode plate 57, and the cathode end plate 58 defines a hydroiodic acid chamber 503. The reaction formula in the hydroiodic acid chamber 503 is: I + e = I - I - +H + =HI.

[0076] Preferably, the cathode plate 57 is made of the same material as the anode plate 52, such as titanium coated with precious metals such as ruthenium and iridium. The cathode plate 57 with this design can suppress the generation of hydrogen gas, thereby ensuring that iodine is reduced to iodide ions first and avoiding the generation of hydrogen gas.

[0077] An anion chamber partition 56 is disposed between the cation membrane 55 and the cathode plate 57. The membrane assembly 5 also includes a gasket 59, which is located between the anode end plate 51 and the anode plate 52, between the anode plate 52 and the anode membrane 53, between the anode membrane 53 and the second phosphate chamber partition 54, between the second phosphate chamber partition 54 and the cation membrane 55, between the cation membrane 55 and the anion chamber partition 56, between the anion chamber partition 56 and the cathode plate 57, and between the cathode plate 57 and the cathode end plate 58.

[0078] like Figure 2 and Figure 3As shown, the membrane assembly 5 generally includes an anode end plate 51, an anode plate 52, an anode chamber partition 50, an anode membrane 53, a second phosphate chamber partition 54, a cation membrane 55, an anion chamber partition 56, a cathode plate 57, and a cathode end plate 58 arranged sequentially. A gasket 59 is provided between each of the above adjacent structures. For example, gaskets 59 are provided between the anode end plate 51 and the anode plate 52, between the anode plate 52 and the anode chamber partition 50, between the anode chamber partition 50 and the anode membrane 53, between the anode membrane 53 and the second phosphate chamber partition 54, between the second phosphate chamber partition 54 and the cation membrane 55, between the cation membrane 55 and the anion chamber partition 56, between the anion chamber partition 56 and the cathode plate 57, and between the cathode plate 57 and the cathode end plate 58. In addition, holes (through holes in the thickness direction) are provided at corresponding positions on these gaskets 59, that is, the gaskets 59 are constructed as perforated gaskets, and the holes on them can be used to form fluid communication channels with the structures adjacent to them on the left and right sides.

[0079] The space between the anode plate 51, the anode plate 52, and the anode membrane 53 defines the first phosphoric acid chamber 501, which is the anode chamber where the reaction is an oxidation reaction. The first phosphoric acid chamber 501 plays a role in generating hydrogen ions during the electrochemical reaction that occurs in the membrane assembly 5.

[0080] The space between the anolyte 53 and the cation exchange 55 defines a second phosphoric acid chamber 502, which is a proton chamber where the liquid does not participate in the reaction but only transfers hydrogen ions (protons). The space between the cation exchange 55, the cathode plate 57, and the cathode end plate 58 defines a hydroiodic acid chamber 503, which is an anion chamber where the reaction is a reduction reaction.

[0081] Because the present invention defines a second phosphoric acid chamber 502 that does not participate in the reaction, the concentration of iodide ions permeating from the hydroiodic acid chamber 503 through the cation exchange membrane 55 in the liquid of the second phosphoric acid chamber 502 must be maintained at less than 0.05% (this can be ensured by a deiodination device). Under this concentration condition, iodide ions in the second phosphoric acid chamber 502 will not migrate to the first phosphoric acid chamber 501, thereby ensuring that the anode membrane 53 will not be damaged due to the migration of iodide ions.

[0082] As described above, a small amount of iodide ions may penetrate the cation membrane 55 and enter the second phosphoric acid chamber 502. The second phosphoric acid chamber 502 is connected to the deiodide ion removal device 4, so that the liquid in the second phosphoric acid chamber 502 flows into the deiodide ion removal device 4 for deiodination treatment, thereby removing the iodide ions in the original liquid. The liquid after the iodide ions are removed returns to the second phosphoric acid chamber 502 to continue the cycle.

[0083] Therefore, by adding a second phosphoric acid chamber 502 (proton chamber) and a deiodination device 4 between the anode membrane 53 and the cation membrane 55, even if iodide ions can pass through the cation membrane 55 into the second phosphoric acid chamber 502, the iodide ion concentration in the second phosphoric acid chamber 502 is reduced to less than 0.05% through the deiodination process. Under this concentration condition, no iodide ions will pass through the anode membrane 53 into the first phosphoric acid chamber 501 (cation chamber), thereby improving the service life of the cation membrane 55 and ensuring the production efficiency of the membrane module.

[0084] like Figure 4 As shown, the anode plate 51 has a flow channel, which includes multiple side flow channels 511, multiple upper flow channels 512, and multiple lower flow channels 513. These flow channels are independent of each other. Figure 4 and Figure 6 As shown, multiple flow channels 512 at the upper end of the anode end plate are arranged side by side, and their extension direction is perpendicular to the extension direction of the flow channel 511 on the side of the anode end plate.

[0085] like Figure 5 As shown, the flow channel 511 on the side of the anode plate can be, for example, a hole opened on the left and right sides of the anode plate 51. The upper flow channel 512 and the lower flow channel 513 of the anode plate can be holes opened on the upper surface of the anode plate 51 near its upper end and near its lower end, respectively. The upper flow channel 512 and the lower flow channel 513 of the anode plate are symmetrically arranged about the anode plate 51.

[0086] Multiple anode end plate side channels 511 can be connected to the first phosphoric acid circulation tank 11 respectively, so that the liquid can circulate between the first phosphoric acid circulation tank 11 and the first phosphoric acid chamber 501; multiple anode end plate upper channel channels 512 can be connected to the second phosphoric acid circulation tank 21 and the deiodination circulation tank 42 respectively, and multiple anode end plate lower channel channels 513 can be connected to the second phosphoric acid circulation tank 21 and the deiodination circulation tank 42 respectively, so that the liquid can circulate between the second phosphoric acid circulation tank 21 and the deiodination circulation tank 42.

[0087] like Figure 7 As shown, the anode plate 52 is provided with a plurality of anode plate flow channels 522. The anode plate flow channels 522 are constructed as holes that penetrate the thickness direction of the anode plate 52 (for example, 6 holes are provided, or more holes can be provided). The holes on the anode plate 52 used to form the anode plate flow channels 522 correspond one-to-one with the holes on the anode end plate 51 used to form the upper end flow channel 512 and the lower end flow channel 513 of the anode end plate. Therefore, after the anode plate 52 and the anode end plate 51 are pressed together, the holes on the two are aligned with each other, thereby forming a flow channel for liquid to flow.

[0088] like Figure 9As shown, the second phosphate chamber partition 54 is provided with a plurality of second phosphate chamber partition channels 541, which are constructed as holes (e.g., 6 holes, or more holes) penetrating the thickness direction of the second phosphate chamber partition and grooves communicating with the corresponding holes. The holes on the second phosphate chamber partition 54 for forming the second phosphate chamber partition channels 541, the holes on the anode plate 52 for forming the anode plate channels 522, and the holes on the anode end plate 51 for forming the upper end channel 512 and the lower end channel 513 of the anode end plate are one-to-one corresponding. Therefore, after the second phosphate chamber partition 54, the anode plate 52 and the anode end plate 51 are pressed together, the holes on them are aligned with each other, thereby forming a flow channel for liquid to flow.

[0089] like Figure 10b As shown, the anode chamber partition 50 is provided with multiple anode chamber partition channels 5001. The anode chamber partition channels 5001 are constructed as holes that penetrate the thickness direction of the anode chamber partition 50 (for example, 6 holes are provided, or more holes can be provided). The holes on the second phosphate chamber partition 54 for forming the second phosphate chamber partition channel 541, the holes on the anode plate 52 for forming the anode plate channel 522, and the holes on the anode end plate 51 for forming the upper end channel 512 and the lower end channel 513 of the anode end plate are one-to-one corresponding. Therefore, after the second phosphate chamber partition 54, the anode chamber partition 50, the anode plate 52 and the anode end plate 51 are pressed together, the holes on them are aligned with each other, thereby forming a flow channel for liquid to flow.

[0090] Similarly, as Figure 10a As shown, the anode membrane 53 is provided with multiple anode membrane channels 531. The anode membrane channels 531 are constructed as holes that penetrate the thickness direction of the anode membrane 53 (for example, 6 holes are provided, or more holes can be provided). The holes on the anode membrane 53 for forming the anode membrane channels 531, the holes on the anode chamber partition 50 for forming the anode chamber partition channel 5001, the holes on the second phosphate chamber partition 54 for forming the second phosphate chamber partition channel 541, and the holes on the anode plate 52 for forming the anode plate channel 522 correspond one-to-one with the holes on the anode end plate 51 for forming the upper end channel 512 and the lower end channel 513 of the anode end plate. Therefore, after the anode chamber partition 50, the anode membrane 53, the second phosphate chamber partition 54, the anode plate 52 and the anode end plate 51 are pressed together, the holes on them are aligned with each other, thereby forming a flow channel for liquid to flow.

[0091] like Figure 12 As shown, the cathode end plate 58 has a cathode end plate flow channel 581, which can be one type or multiple, for communicating with the hydroiodic acid circulation device 3, so that the liquid can circulate between the hydroiodic acid chamber 503 and the hydroiodic acid circulation device 3. The cathode end plate flow channel 581 can be a hole formed on the side of the cathode end plate 58.

[0092] Understandably, the holes on the gasket 59 correspond one-to-one with the holes on the anode end plate 51, anode plate 52, anode chamber partition 50, anode membrane 53, and second phosphate chamber partition 54 used to form flow channels (i.e., the number of holes and the spacing between adjacent holes are the same). After pressing it between the anode end plate 51 and anode plate 52, and between the anode membrane 53 and second phosphate chamber partition 54, a flow channel for liquid to flow can be formed.

[0093] Similarly, the cathode end plate 58, cathode plate 57, and cathode chamber partition 56, as well as the gasket therebetween, are fluidly connected through perforated channels, allowing liquid to enter the hydroiodic acid circulation device 3 from the hydroiodic acid chamber 503 through these perforated channels, and from the hydroiodic acid circulation device 3 to the hydroiodic acid chamber 503 through these perforated channels.

[0094] like Figure 7 and Figure 8 As shown, the anode plate 52 is also provided with multiple anode plate connecting ears 521, and the cathode plate 57 is also provided with multiple cathode plate connecting ears 571. Figure 1 As shown, membrane module 5 is connected to power supply 6, which is a DC power supply. Its positive terminal is electrically connected to anode plate connecting lug 521, and its negative terminal is electrically connected to cathode plate connecting lug 571, thereby supplying power to membrane module 5.

[0095] The raw material for preparing hydroiodic acid is elemental iodine. Elemental iodine is dissolved in hydroiodic acid (e.g., at a concentration of 20%) to prepare hydrogen triiodide, which is stored in a hydrogen triiodide storage tank. A metering feed pump is connected to the storage tank, and this pump is connected to the outlet of the hydroiodic acid circulation pump. Hydrogen triiodide is metered into the inlet of the hydroiodic acid chamber 503 by the metering pump and enters membrane module 5 to undergo a reduction reaction, reducing hydrogen triiodide to hydroiodic acid. A finished product outlet is located at the outlet of the hydroiodic acid chamber 503 of membrane module 5. This outlet is controlled by two or more regulating valves, adjusting the output to match the metering pump's input. The output hydroiodic acid product then enters the hydroiodic acid storage tank. The hydroiodic acid product can be further purified into a 57% qualified hydroiodic acid product through an evaporation and concentration system.

[0096] In addition, the present invention also provides a method for preparing hydroiodic acid, comprising the following steps:

[0097] The first step is to place a cation exchange membrane 55 between the anode membrane 53 and the cathode plate 57 in membrane module 5. This invention differs from existing membrane module structures with one membrane and two chambers. By setting two cation exchange membranes, namely the anode membrane 53 and the cation exchange membrane 55, this invention can improve the service life of the membranes and ensure the production efficiency of the membrane module.

[0098] In the second step, the space between the anode membrane 53 and the cation membrane 55 defines the second phosphoric acid chamber 502 of the membrane assembly 5. The second phosphoric acid chamber 502 is connected to the deiodination ion device 4, so that the liquid in the second phosphoric acid chamber 502 flows into the deiodination ion device 4.

[0099] In the third step, the liquid in the deiodination ion device 4 undergoes solid-liquid separation to remove elemental iodine from the liquid, and the deiodinated liquid flows into the second phosphoric acid recycling device 2.

[0100] In the fourth step, an oxidation reaction occurs in the first phosphate chamber 501.

[0101] In the fifth step, the liquid in the hydroiodic acid chamber 503 of the membrane module 5 circulates between the hydroiodic acid chamber 503 and the hydroiodic acid circulation device 3. A reduction reaction occurs in the hydroiodic acid chamber 503 to reduce hydrogen triiodide to hydroiodic acid.

[0102] Therefore, it can be seen that in the process of obtaining hydroiodic acid in the above-mentioned cycle, by performing deiodination treatment on the liquid in the second phosphoric acid chamber 502, even if a small amount of iodide ions can penetrate the cation membrane 55 and enter the second phosphoric acid chamber 502, they will enter the deiodination ion device 4 for deiodination treatment along with the liquid circulation. The deiodinated liquid is then returned to the second phosphoric acid chamber 502 in the membrane group 5 for recycling. At this time, the circulating liquid is the liquid from which iodide ions have been removed, thereby preventing the iodide ions in the second phosphoric acid chamber 502 from transferring to the anode membrane 53 and accumulating there, and oxidizing into elemental iodine, which would damage the anode membrane 53. This can greatly improve the service life of the anode membrane 53 and the production efficiency of the membrane group.

[0103] Although the invention has been described with reference to preferred embodiments, various modifications can be made and components can be replaced with equivalents without departing from the scope of the invention. In particular, the technical features mentioned in the various embodiments can be combined in any manner as long as there is no structural conflict. The invention is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. An apparatus for preparing hydroiodic acid, characterized in that, include: The device comprises a first phosphoric acid circulation unit, a second phosphoric acid circulation unit, a hydroiodic acid circulation unit, an iodine removal ion unit, and a membrane module, wherein the membrane module includes a first phosphoric acid chamber, a second phosphoric acid chamber, and a hydroiodic acid chamber arranged in sequence and in fluid communication. The first phosphoric acid chamber is connected to the first phosphoric acid circulation device to form a circulation system, so that the liquid circulates between the first phosphoric acid chamber and the first phosphoric acid circulation device. The second phosphoric acid chamber is connected to the deiodination ionization device, and the liquid in the deiodination ionization device flows into the second phosphoric acid circulation device after deiodination; The hydroiodic acid chamber is connected to the hydroiodic acid circulation device, so that the liquid circulates between the hydroiodic acid chamber and the hydroiodic acid circulation device; The membrane assembly comprises, in sequence, an anode end plate, an anode plate, an anode chamber partition, an anode membrane, a second phosphate chamber partition, a cation membrane, an anion chamber partition, a cathode plate, and an anion end plate; The space between the anode end plate, the anode plate and the anode membrane defines a first phosphoric acid chamber, which is an anode chamber; The space between the anode membrane and the cation membrane defines a second phosphate chamber, which is a proton chamber in which the liquid only transfers hydrogen ions; The space between the cation membrane, the cathode plate, and the cathode end plate defines a hydroiodic acid chamber, which is an anion chamber.

2. The hydroiodic acid preparation apparatus according to claim 1, characterized in that, The concentration of iodide ions permeating from the hydroiodic acid chamber through the cation membrane in the liquid of the second phosphoric acid chamber is less than 0.05%.

3. The hydroiodic acid preparation apparatus according to claim 1, characterized in that, The second phosphoric acid chamber partition is provided with multiple second phosphoric acid chamber partition channels. The liquid in the second phosphoric acid chamber can flow into the deiodination ion device through the multiple second phosphoric acid chamber partition channels respectively, and the liquid in the second phosphoric acid circulation device can flow into the second phosphoric acid chamber through the second phosphoric acid chamber partition channels.

4. The hydroiodic acid preparation apparatus according to claim 1, characterized in that, The cathode end plate has a cathode end plate flow channel.

5. The hydroiodic acid preparation apparatus according to claim 4, characterized in that, The membrane assembly further includes gaskets located between the anode end plate and the anode plate, between the anode plate and the anode membrane, between the anode membrane and the second phosphate chamber partition, between the second phosphate chamber partition and the cation membrane, between the cation membrane and the anion chamber partition, between the anion chamber partition and the cathode plate, and between the cathode plate and the cathode end plate.

6. The hydroiodic acid preparation apparatus according to claim 1 or 2, characterized in that, The deiodide ionization device includes: An iodine removal circulation tank, the inlet of which is connected to the second phosphate chamber; A ceramic membrane iodine separation device, wherein the inlet of the ceramic membrane iodine separation device is connected to the outlet of the iodine removal circulation tank, and the outlet of the ceramic membrane iodine separation device is connected to the inlet of the second phosphoric acid circulation device, the ceramic membrane iodine separation device being used to separate elemental iodine from the liquid and input the liquid after solid-liquid separation into the second phosphoric acid circulation device; and A dosing device is connected to the pipeline between the inlet of the ceramic membrane iodine separation device and the outlet of the iodine removal circulation tank.

7. The hydroiodic acid preparation apparatus according to claim 6, characterized in that, The dosing device includes a metering tank and a metering pump connected to the metering tank. The metering tank contains hydrogen peroxide, and the metering pump can add the hydrogen peroxide in the metering tank to the ceramic membrane iodine separation device.

8. A method for preparing hydroiodic acid using the apparatus for preparing hydroiodic acid according to any one of claims 1-7, characterized in that, Includes the following steps: A cation exchange membrane is placed between the anode membrane and the cathode plate of the membrane module; The second phosphoric acid chamber defined between the anode membrane and the cation membrane is connected to the deiodide ionization device, so that the liquid in the second phosphoric acid chamber flows into the deiodide ionization device; The liquid in the iodine removal ionization device undergoes solid-liquid separation to remove elemental iodine. The iodine-removed liquid then flows into the second phosphoric acid recycling unit. The liquid in the hydroiodic acid chamber of the membrane module circulates between the hydroiodic acid chamber and the hydroiodic acid circulation device.

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