JP2007314408A - Hydrogen production apparatus and hydrogen production method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hydrogen production apparatus in which hydrogen production efficiency is improved by effectively applying a water permselective membrane to concentrate a hydrogen iodide aqueous solution. <P>SOLUTION: The hydrogen production apparatus is provided with a Bunsen reaction apparatus for producing a sulfuric acid aqueous solution and the hydrogen iodide aqueous solution from iodine, sulfur dioxide and water, a hydrogen iodide concentrating and decomposing apparatus for decomposing hydrogen iodide after concentrating the hydrogen iodide aqueous solution to obtain hydrogen and iodine to be supplied to the Bunsen reaction apparatus and a sulfuric acid concentrating and decomposing apparatus for decomposing sulfuric acid after concentrating the sulfuric acid aqueous solution, wherein a water membrane separation apparatus 6 for membrane-separating water by passing the hydrogen iodide aqueous solution through the water permselective membrane is provided in the hydrogen iodide concentrating and decomposing apparatus. The water membrane separation apparatus 6 is provided with a heat supply instrument 26 for supplying heat to keep the temperature of the hydrogen iodide aqueous solution to be treated by the water permselective membrane to equal to or higher than a temperature at which iodine is precipitated. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a hydrogen production apparatus and a hydrogen production method for producing hydrogen by thermally decomposing water using iodine and sulfur dioxide.

An IS (Iodine Sulfur) method is known as a method for producing hydrogen by thermally decomposing water (see Patent Document 1). The IS method is composed of the following three steps.
I Bunsen reaction process An aqueous sulfuric acid solution and aqueous hydrogen iodide solution are produced from iodine, sulfur dioxide and water.
II Hydrogen iodide concentration and decomposition step After concentrating the hydrogen iodide aqueous solution obtained by the Bunsen reaction step, hydrogen iodide is decomposed to obtain hydrogen as a product and iodine to be supplied to the Bunsen reaction step.
III Sulfuric acid concentration and decomposition step After the sulfuric acid aqueous solution obtained by the Bunsen reactor is concentrated, sulfuric acid is decomposed to obtain oxygen and sulfur dioxide to be supplied to the Bunsen reaction step. The sulfur dioxide obtained in this step can be obtained by further decomposing sulfur trioxide produced by the decomposition of sulfuric acid by the sulfur trioxide decomposition step.
The three steps I to III are connected to each other to form a closed cycle.

  The Bunsen reaction is an exothermic reaction, but the decomposition reaction of hydrogen iodide in the hydrogen iodide concentration and decomposition process, the decomposition reaction of sulfuric acid in the concentration and decomposition process of sulfuric acid, and the decomposition reaction of sulfur trioxide produced by the decomposition of sulfuric acid are considered endothermic reactions. The Therefore, when realizing the IS method, it is necessary to supply thermal energy to the hydrogen iodide concentration and decomposition step and the sulfuric acid concentration and decomposition step.

When the hydrogen iodide aqueous solution is concentrated in the hydrogen iodide concentration and decomposition step, since hydrogen iodide and water azeotrope, it is difficult to concentrate hydrogen iodide beyond the azeotropic point by a simple distillation method. Therefore, a method of concentrating under an azeotropic condition by circulating a hydrogen iodide aqueous solution is performed. However, if the circulation operation is performed, extra heat energy is required as compared with the case where the circulation operation is not performed, and as a result, the input energy cannot be reduced.
In order to solve such a problem of the distillation method, Patent Document 1 discloses that in a hydrogen iodide concentration step, a hydrogen iodide aqueous solution is permeabilized with a water selective permeable membrane and the permeated water is evaporated at room temperature. A technique for reducing the amount of high-temperature heat energy used has been proposed. In other words, a technology has been proposed in which hydrogen iodide aqueous solution is dehydrated and concentrated using low-temperature thermal energy supplied from the surrounding environment for the energy required for permeation treatment, and the resulting concentrated aqueous solution is subjected to thermochemical decomposition to obtain hydrogen. ing.
JP 2004-107115 A (FIG. 1)

  However, since the technique described in Patent Document 1 uses a water selective permeable membrane at room temperature, there is a problem that the water membrane separation efficiency is lowered. This is because when concentration is performed at room temperature, iodine solidifies and precipitates, and the water selective permeable membrane is blocked by the precipitated iodine, so that the water membrane separation efficiency is lowered. Moreover, since it is impossible to raise the temperature lowered by the latent heat of vaporization to about 100 ° C., which is the hydrogen production process temperature, with a room temperature heat source, a large amount of heat energy is input.

  The present invention has been made in view of such circumstances, and effectively applies a water selective permeable membrane to concentrate an aqueous hydrogen iodide solution to improve hydrogen production efficiency and a hydrogen production method. The purpose is to provide.

In order to solve the above problems, the hydrogen production apparatus and the hydrogen production method of the present invention employ the following means.
That is, the hydrogen production apparatus according to the present invention includes a Bunsen reactor that generates a sulfuric acid aqueous solution and a hydrogen iodide aqueous solution from iodine, sulfur dioxide, and water, and a hydrogen iodide aqueous solution obtained by concentrating the hydrogen iodide aqueous solution obtained by the Bunsen reactor. Hydrogen iodide concentrating and decomposing apparatus for decomposing hydrogen iodide to obtain hydrogen as a product and iodine to be supplied to the Bunsen reactor, and concentrating the sulfuric acid aqueous solution obtained by the Bunsen reactor, decomposing sulfuric acid, and oxygen And a sulfuric acid concentration and decomposition apparatus for obtaining sulfur dioxide to be supplied to the Bunsen reactor, and the hydrogen iodide concentration and decomposition apparatus includes a water membrane separation apparatus for separating a hydrogen iodide aqueous solution through a water selective permeable membrane. In the hydrogen production apparatus, the water membrane separator is provided with hydrogen iodide water treated by the water selective permeable membrane. With respect to the liquid, characterized in that the heat supply heat for maintaining a higher temperature which iodine precipitates feeder is provided.

Since the hydrogen iodide aqueous solution is concentrated by membrane separation of the water in the hydrogen iodide aqueous solution by the moisture membrane separator, the progress of concentration is hindered by the azeotropic conditions of water and hydrogen iodide. There is no. Therefore, extra heat energy is not required as compared with the case of concentrating under the azeotropic condition by the distillation method.
Further, when operated at room temperature, there is a possibility that iodine in the hydrogen iodide aqueous solution is precipitated due to a decrease in temperature due to latent heat of evaporation in which water becomes water vapor. If it does so, the deposited iodine will block a water selective permeable membrane, and the water membrane separation efficiency of hydrogen iodide aqueous solution will fall. Therefore, by supplying heat to the moisture membrane separation device with the heat supply device so as to maintain a temperature equal to or higher than the temperature at which iodine precipitates, the precipitation can be prevented and the concentration can proceed.

  Furthermore, the hydrogen production apparatus uses exhaust heat in the hydrogen production apparatus as a heat source of the heat supply device.

Since the exhaust heat in the hydrogen production apparatus is used as the heat source of the heat supply device, it is not necessary to provide a separate heat source. Therefore, it is possible to reduce the thermal energy input to the moisture membrane separator. Thereby, compared with the case where it concentrates under azeotropic conditions by the distillation method, the thermal energy put into a hydrogen iodide concentration process can be reduced significantly.
As the exhaust heat used, for example, exhaust heat in a sulfuric acid concentration decomposition apparatus or a hydrogen iodide concentration decomposition apparatus is used.

  In addition, the hydrogen production apparatus of the present invention includes a Bunsen reactor that generates an aqueous sulfuric acid solution and an aqueous hydrogen iodide solution from iodine, sulfur dioxide, and water, and an iodination after concentrating the aqueous hydrogen iodide solution obtained by the Bunsen reactor. Hydrogen iodide concentration and decomposition apparatus that decomposes hydrogen to obtain hydrogen as a product and iodine to be supplied to the Bunsen reactor; and after concentrating the sulfuric acid aqueous solution obtained by the Bunsen reactor, the sulfuric acid is decomposed and oxygen and A sulfuric acid concentration and decomposition device for obtaining sulfur dioxide to be supplied to the Bunsen reactor, and the hydrogen iodide concentration and decomposition device includes a water membrane separation device for separating a hydrogen iodide aqueous solution by a water selective permeable membrane. In the hydrogen production apparatus provided, an iodine removal apparatus for depositing and removing iodine is provided upstream of the moisture membrane separation apparatus. Wherein the water membrane separation apparatus for hydrogen iodide solution to be processed by the water permselective membrane, characterized in that the heat supply for supplying the vaporization latent heat of the heat is provided.

Iodine removal device lowers the temperature of the hydrogen iodide aqueous solution before water membrane separation by the water selective permeable membrane, so that iodine is precipitated and removed in advance. Even if it falls, iodine does not precipitate. Therefore, the progress of water membrane separation by the water selective membrane permeable membrane is not hindered. As a result, the concentration can be performed at room temperature without reducing the water membrane separation efficiency of the aqueous hydrogen iodide solution.
Further, since the concentration can proceed at room temperature, it is possible to reduce the thermal energy input to the moisture membrane separator.

  In addition, the hydrogen production apparatus of the present invention includes a Bunsen reactor that generates an aqueous sulfuric acid solution and an aqueous hydrogen iodide solution from iodine, sulfur dioxide, and water, and an iodination after concentrating the aqueous hydrogen iodide solution obtained by the Bunsen reactor. Hydrogen iodide concentration and decomposition apparatus that decomposes hydrogen to obtain hydrogen as a product and iodine to be supplied to the Bunsen reactor; and after concentrating the sulfuric acid aqueous solution obtained by the Bunsen reactor, the sulfuric acid is decomposed and oxygen and A sulfuric acid concentration and decomposition device for obtaining sulfur dioxide to be supplied to the Bunsen reactor, and the hydrogen iodide concentration and decomposition device includes a water membrane separation device for separating a hydrogen iodide aqueous solution by a water selective permeable membrane. In the hydrogen production apparatus provided, the hydrogen iodide aqueous solution is concentrated on the upstream side of the moisture membrane separator, and the hydrogen iodide An electrodialyzer for removing iodine in the solution is provided, and the water membrane separator is a heat supply device that supplies heat for the latent heat of evaporation to the hydrogen iodide aqueous solution treated by the water selective permeable membrane. Is provided.

According to such a configuration, the hydrogen iodide aqueous solution before the water membrane separation by the water selective permeable membrane is concentrated by the electrodialyzer provided on the upstream side of the water membrane separator, Iodine is removed. Therefore, the concentration can be further advanced in the water membrane separator. Further, since iodine in the hydrogen iodide aqueous solution has been removed, even if the solution temperature is lowered to room temperature at the stage of moisture membrane separation, iodine does not precipitate. Therefore, the progress of water membrane separation by the water selective membrane permeable membrane is not hindered. Thereby, it can concentrate at room temperature, without reducing the water membrane separation efficiency of hydrogen iodide aqueous solution. As a result, it is possible to reduce the thermal energy input to the moisture membrane separator.
Moreover, since iodine is produced | generated in a liquid state by the effect | action of an electrodialyzer, the removed iodine can be used as a recycle solution with a liquid state. Thus, since the solidified iodine does not exist in the recycle solution, the recycle solution can be easily used.

  Furthermore, the hydrogen production apparatus uses seawater as a heat source of the heat supply unit.

  Since seawater is used as the heat source of the heat supply device, there is no need to provide a new heat source. Therefore, it is possible to greatly reduce the heat energy input to the moisture membrane separation device.

  Each of the hydrogen production apparatuses is characterized in that an electrodialyzer for concentrating the hydrogen iodide aqueous solution exceeding the azeotropic concentration of the hydrogen iodide aqueous solution is provided on the downstream side of the moisture membrane separator. To do.

  Since an electrodialyzer is installed on the downstream side of the moisture membrane separator, even if the concentration of the aqueous solution of hydrogen iodide does not rise only by the moisture membrane separation, the aqueous solution of hydrogen iodide exceeds the azeotropic concentration. It can be concentrated.

  Each of the hydrogen production apparatuses is characterized in that a distillation column for further concentrating a hydrogen iodide aqueous solution having a concentration exceeding the azeotropic concentration is provided on the downstream side of the moisture membrane separation apparatus.

  The water membrane separator, or the water membrane separator and the electrodialyzer are used to exceed the azeotropic point of the hydrogen iodide aqueous solution, and then the hydrogen iodide aqueous solution having a concentration exceeding the azeotropic composition is further concentrated using the distillation column. Therefore, no extra heat energy is required as compared with the case of concentration by distillation under azeotropic conditions. That is, the heat energy input to the hydrogen iodide concentration step can be reduced as much as possible.

  Furthermore, the hydrogen production apparatus uses exhaust heat in the hydrogen production apparatus as a heat source of the distillation column.

Since the exhaust heat in the hydrogen production apparatus is used as the heat source for the distillation column, there is no need to provide a separate heat source. Therefore, it is possible to reduce the heat energy input to the distillation column. Thereby, compared with the case where it concentrates under azeotropic conditions by a distillation method, input heat energy can be reduced significantly.
As the exhaust heat used, for example, exhaust heat in a sulfuric acid concentration decomposition apparatus or a hydrogen iodide concentration decomposition apparatus is used.

  Further, the hydrogen production method of the present invention includes a Bunsen reaction step for producing a sulfuric acid aqueous solution and a hydrogen iodide aqueous solution from iodine, sulfur dioxide, and water, and an iodination after concentrating the hydrogen iodide aqueous solution obtained by the Bunsen reaction step. Hydrogen iodide concentration and decomposition step for decomposing hydrogen to obtain hydrogen as a product and iodine to be supplied to the Bunsen reaction step; after concentrating the sulfuric acid aqueous solution obtained by the Bunsen reaction step, the sulfuric acid is decomposed and oxygen and A sulfuric acid concentration and decomposition step for obtaining sulfur dioxide to be supplied to the Bunsen reaction step, wherein the hydrogen iodide concentration and decomposition step includes a water membrane separation step of separating a hydrogen iodide aqueous solution with a water selective permeable membrane. In the hydrogen production method provided, in the water membrane separation step, a hydrogen iodide aqueous solution treated by the water selective permeable membrane is used. Characterized in that the heat supply step of supplying heat to maintain the higher temperature which iodine precipitates is provided.

Since the hydrogen iodide aqueous solution was concentrated by separating the water in the hydrogen iodide aqueous solution through the water membrane separation step, the progress of concentration was hindered by the azeotropic conditions of water and hydrogen iodide. There is no. Therefore, extra heat energy is not required as compared with the case of concentrating under the azeotropic condition by the distillation method.
Further, when operated at room temperature, there is a possibility that iodine in the hydrogen iodide aqueous solution is precipitated due to a decrease in temperature due to latent heat of evaporation in which water becomes water vapor. If it does so, the deposited iodine will block a water selective permeable membrane, and the water membrane separation efficiency of hydrogen iodide aqueous solution will fall. Thus, by supplying heat to the moisture membrane separation step in the heat supply step so as to maintain a temperature equal to or higher than the temperature at which iodine precipitates, the iodine can be prevented from being precipitated and the concentration can proceed.

  Further, the hydrogen production method of the present invention includes a Bunsen reaction step for producing a sulfuric acid aqueous solution and a hydrogen iodide aqueous solution from iodine, sulfur dioxide, and water, and an iodination after concentrating the hydrogen iodide aqueous solution obtained by the Bunsen reaction step. Hydrogen iodide concentration and decomposition step for decomposing hydrogen to obtain hydrogen as a product and iodine to be supplied to the Bunsen reaction step; after concentrating the sulfuric acid aqueous solution obtained by the Bunsen reaction step, the sulfuric acid is decomposed and oxygen and A sulfuric acid concentration and decomposition step for obtaining sulfur dioxide to be supplied to the Bunsen reaction step, wherein the hydrogen iodide concentration and decomposition step includes a water membrane separation step of separating a hydrogen iodide aqueous solution with a water selective permeable membrane. In the provided hydrogen production method, an iodine removal step for depositing and removing iodine is provided upstream of the moisture membrane separation step. Wherein the water membrane separation step, to the aqueous solution of hydrogen iodide to be processed by the water permselective membrane, characterized in that the heat supply step of supplying a vaporization latent heat of the heat is provided.

In the iodine removal step, the temperature of the hydrogen iodide aqueous solution before the water membrane separation by the water membrane separation step was lowered, so that iodine was precipitated and removed in advance. Even if it falls, iodine does not precipitate. Therefore, the progress of moisture membrane separation by the water selective membrane permeable membrane is not hindered. As a result, the concentration can be performed at room temperature without reducing the water membrane separation efficiency of the aqueous hydrogen iodide solution.
Further, since the concentration can proceed at room temperature, the thermal energy input to the moisture membrane separation process can be reduced.

  Further, the hydrogen production method of the present invention includes a Bunsen reaction step for producing a sulfuric acid aqueous solution and a hydrogen iodide aqueous solution from iodine, sulfur dioxide, and water, and an iodination after concentrating the hydrogen iodide aqueous solution obtained by the Bunsen reaction step. Hydrogen iodide concentration and decomposition step for decomposing hydrogen to obtain hydrogen as a product and iodine to be supplied to the Bunsen reaction step; after concentrating the sulfuric acid aqueous solution obtained by the Bunsen reaction step, the sulfuric acid is decomposed and oxygen and A sulfuric acid concentration and decomposition step for obtaining sulfur dioxide to be supplied to the Bunsen reaction step, wherein the hydrogen iodide concentration and decomposition step includes a water membrane separation step of separating a hydrogen iodide aqueous solution with a water selective permeable membrane. In the hydrogen production method provided, the upstream side of the water membrane separation step includes a step of concentrating a hydrogen iodide aqueous solution and the iodination. A step of removing iodine in the aqueous solution is provided, and the water membrane separation step includes a heat supply step of supplying heat for the latent heat of evaporation to the hydrogen iodide aqueous solution treated by the water selective permeable membrane. It is provided.

According to such a configuration, on the upstream side of the moisture membrane separation step, the aqueous hydrogen iodide solution before the moisture membrane separation is concentrated by the water selective permeable membrane, and iodine in the aqueous hydrogen iodide solution is removed. Therefore, concentration can be further advanced in the moisture membrane separation step. Further, since iodine in the hydrogen iodide aqueous solution has been removed, even if the solution temperature is lowered to room temperature at the stage of moisture membrane separation, iodine does not precipitate. Therefore, the progress of water membrane separation by the water selective membrane permeable membrane is not hindered. Thereby, it can concentrate at room temperature, without reducing the water membrane separation efficiency of hydrogen iodide aqueous solution. As a result, it is possible to reduce the thermal energy input to the moisture membrane separation process.
Moreover, since iodine is produced | generated in a liquid state in an electrodialysis process, the removed iodine can be used as a recycle solution with a liquid state. Thus, since the solidified iodine does not exist in the recycle solution, the recycle solution can be easily used.

According to the present invention, the heat supply device supplies heat for maintaining the temperature above the temperature at which iodine is deposited to the moisture membrane separation device to prevent iodine precipitation. The efficiency can be improved and the aqueous hydrogen iodide solution can be concentrated.
In addition, iodine is removed in advance by an iodine removal device, and when water selective permeable membrane is applied at room temperature, it is decided to avoid precipitation of iodine. can do.

Embodiments according to the present invention will be described below with reference to the drawings.
[First embodiment]
Hereinafter, a first embodiment of the present invention will be described with reference to FIGS.
FIG. 1 shows a schematic configuration of the hydrogen production apparatus 1.
The hydrogen production apparatus 1 produces water (and oxygen) as a product by decomposing water as a raw material by thermal decomposition. The hydrogen production apparatus 1 employs an IS (Iodine Sulfur) method, and includes a Bunsen reaction apparatus 2, a hydrogen iodide concentration and decomposition apparatus 3, and a sulfuric acid concentration and decomposition apparatus 4.

As a heat source supplied to the hydrogen iodide concentrating / decomposing apparatus 3 and the sulfuric acid concentrating / decomposing apparatus 4, nuclear heat of a high temperature gas furnace (not shown) is used. That is, the sensible heat of the secondary helium gas obtained through the intermediate heat exchanger 10 is used.
The intermediate heat exchanger 10 performs heat exchange between the primary helium gas heated to the high temperature by the nuclear heat of the high temperature gas furnace and the secondary helium gas that gives heat to the hydrogen production apparatus 1 side. The intermediate heat exchanger 10 is connected to a primary side pipe 10a through which primary helium gas flows and a secondary side pipe 10b through which secondary helium gas flows. The secondary helium gas flowing through the secondary side pipe 10b is heated to about 880 ° C. in the intermediate heat exchanger 10, and the pressure thereof is about 4 MPa.
The secondary helium gas heated in the intermediate heat exchanger 10 exchanges heat with the sulfur trioxide decomposer 17, the sulfuric acid decomposer 15, and the hydrogen iodide decomposer 11, which will be described later.

The Bunsen reactor 2 includes a Bunsen reactor 5 and a two-phase separator 7.
In the Bunsen reactor 5, water (H ₂ O) as a raw material, iodine (I ₂ ) supplied from the hydrogen iodide concentration and decomposition device 3, and sulfur dioxide (SO ₂ ) supplied from the sulfuric acid concentration and decomposition device 4. ) Is supplied. In the Bunsen reactor 5, for example, a Bunsen reaction according to the following equation is performed under conditions of 0.1 MPa (gauge pressure) and 100 ° C. to generate an aqueous hydrogen iodide solution and an aqueous sulfuric acid solution. Since the Bunsen reaction is an exothermic reaction, no energy is input from the outside.
SO ₂ (g) + I ₂ (L) + 2H ₂ O → H ₂ SO ₄ (aq) + 2HI (aq) (1)
In the two-phase separator 7, the aqueous sulfuric acid solution and the aqueous hydrogen iodide solution obtained in the Bunsen reactor 5 are separated. The inside of the two-phase separator 7 is set to conditions of 0.1 MPa (gauge pressure) and 100 ° C., for example. The hydrogen iodide aqueous solution and the sulfuric acid aqueous solution separated in the two-phase separator 7 are led to the hydrogen iodide concentration and decomposition device 3 and the sulfuric acid concentration and decomposition device 4, respectively.

The hydrogen iodide concentrating and decomposing apparatus 3 includes a hydrogen iodide refining and concentrating device 9 and a hydrogen iodide decomposing device 11.
The hydrogen iodide refining concentrator 9 purifies the hydrogen iodide aqueous solution and concentrates the hydrogen iodide aqueous solution, for example, under conditions of 1 MPa (gauge pressure) and 100 to 234 ° C. Hydrogen iodide is vaporized in the hydrogen iodide refining concentrator 9 and guided to the hydrogen iodide decomposer 11. The hydrogen iodide refining concentrator 9 is charged with heat energy necessary for the refining and concentrating process.

The hydrogen iodide decomposer 11 performs the decomposition of hydrogen iodide according to the following equation under the conditions of 1 MPa (gauge pressure) and 450 ° C., for example.
2HI (g) → H ₂ (g) + I ₂ (g) (2)
The hydrogen iodide decomposition reaction is an endothermic reaction, and therefore heat energy is input. That is, the hydrogen iodide decomposition reaction of formula (2) proceeds by heat exchange with the gas pipe 13 through which the secondary helium gas heated in the intermediate heat exchanger 10 flows.
Hydrogen decomposed in the hydrogen iodide decomposer 11 is taken out as a product. The iodine decomposed in the hydrogen iodide decomposer 11 is led to the Bunsen reactor 5. Unreacted hydrogen iodide is returned to the hydrogen iodide refining concentrator 9.

The sulfuric acid concentration and decomposition apparatus 4 includes a sulfuric acid purification and concentration device 14, a sulfuric acid decomposition device 15, and a sulfur trioxide decomposition device 17.
The sulfuric acid purification concentrator 14 purifies the sulfuric acid and concentrates the sulfuric acid aqueous solution, for example, under conditions of 0.1 MPa (gauge pressure) and 100 to 391 ° C. The sulfuric acid refining concentrator 14 is charged with heat energy necessary for the refining and concentration process. The water separated from the sulfuric acid aqueous solution in the sulfuric acid purification concentrator 14 is sent to the Bunsen reactor 5. The sulfuric acid (liquid) purified and concentrated in the sulfuric acid purification concentrator 14 is guided to the sulfuric acid decomposer 15.

The sulfuric acid decomposer 15 decomposes sulfuric acid according to the following equation under conditions of 2 MPa (gauge pressure) and 391 to 527 ° C., for example.
H ₂ SO ₄ (L) → H ₂ 0 (g) + SO ₃ (g) (3)
The sulfuric acid decomposition reaction is an endothermic reaction, and therefore heat energy is input. That is, the sulfuric acid decomposition reaction of formula (3) proceeds by heat exchange with the gas pipe 19 through which the secondary helium gas heated in the intermediate heat exchanger 10 flows.
The sulfur trioxide and water vapor decomposed in the sulfuric acid decomposer 15 are guided to the sulfur trioxide decomposer 17.

The sulfur trioxide decomposer 17 decomposes sulfur trioxide according to the following equation, for example, under conditions of 2 MPa (gauge pressure) and 527 to 850 ° C.
SO ₃ (g) → SO ₂ (g) + 1 / 2O ₂ (g) (4)
The sulfur trioxide decomposition reaction is an endothermic reaction, and therefore heat energy is input. That is, the sulfur trioxide decomposition reaction of formula (4) proceeds by heat exchange with the gas pipe 20 through which the secondary helium gas heated in the intermediate heat exchanger 10 flows. As shown in FIG. 1, in order to introduce the highest temperature to the sulfur trioxide decomposer 17, the secondary helium gas heated in the intermediate heat exchanger 10 is first introduced to the sulfur trioxide decomposer 17. It has come to be. The secondary helium gas that has finished heat exchange in the sulfur trioxide decomposer 17 performs heat exchange in the sulfuric acid decomposer 15 and the hydrogen iodide decomposer 11.
Oxygen generated in the sulfur trioxide decomposer 17 is taken out of the system as a product. The sulfur dioxide generated in the sulfur trioxide decomposer 17 is led to the Bunsen reactor 5 together with a small amount of water vapor.

  Thus, according to the hydrogen production apparatus 1 according to the present embodiment, by supplying water as a raw material to the Bunsen reactor 2, hydrogen as a product is concentrated from the hydrogen iodide concentration and decomposition apparatus 3, and oxygen is concentrated and decomposed in sulfuric acid It can be obtained from the device 4.

FIG. 2 shows a hydrogen iodide refining and concentrating device 9 of the hydrogen iodide concentrating / decomposing apparatus 3.
The hydrogen iodide purification concentrator 9 includes a water membrane separator 6 that concentrates the aqueous hydrogen iodide solution supplied from the Bunsen reactor 2 by water membrane separation, and a heat supplier 26 that supplies heat to the water membrane separator 6. And a distillation column 24 arranged on the downstream side of the moisture membrane separation device 6.

The water membrane separator 6 separates the water in the hydrogen iodide aqueous solution supplied from the Bunsen reactor 2 and concentrates the hydrogen iodide aqueous solution by passing dry gas through the permeate and removing it as a wet gas. .
At this time, the heat supply device 26 supplies heat to the moisture membrane separation device 6 to maintain a temperature equal to or higher than the temperature at which iodine is deposited. As a heat source of the heat supply device 26, for example, IS process exhaust heat such as a hydrogen iodide concentrating device 3 or a sulfuric acid concentrating / decomposing device 4 is used.
The aqueous hydrogen iodide solution supplied from the Bunsen reactor ₂ also contains iodine (I ₂ ) that has not been reacted in the Bunsen reactor 2.

The hydrogen iodide aqueous solution concentrated to a concentration exceeding the azeotropic concentration of about 16 mol% (HI-H ₂ 0) (for example, 19 mol% (HI-H ₂ 0)) by the water membrane separator 6 is distilled into the distillation column 24. Sent to. The aqueous hydrogen iodide solution sent to the distillation column 24 is further concentrated by a distillation method, and is sent to the hydrogen iodide decomposer 11 (see FIG. 1) as a hydrogen iodide concentrate (or gas). At this time, since the aqueous hydrogen iodide solution exceeds the azeotropic concentration, the progress of concentration by the distillation method is not hindered by the azeotropic conditions of water and hydrogen iodide. Moreover, the water produced by the distillation method is sent to the Bunsen reactor 5 (see FIG. 1) as a recycle solution and reused as raw material water. As the heat source of the distillation column 24, for example, IS process exhaust heat such as a hydrogen iodide concentrating device 3 or a sulfuric acid concentrating / decomposing device 4 is used.
When the hydrogen iodide aqueous solution is sufficiently concentrated by the water membrane separation by the water membrane separator 6, the distillation column 24 may be omitted and the hydrogen iodide solution may be sent directly to the hydrogen iodide decomposer 11.

FIG. 3 shows details of the above-described moisture membrane separation device 6.
The moisture membrane separation device 6 is partitioned into a hydrogen iodide aqueous solution supply chamber 21 and a permeation chamber 23 by a water selective permeable membrane 8.
In this embodiment, a Nafion membrane (“Nafion” is a registered trademark of DuPont), which is a solid polymer ion exchange membrane, is used as the water selective permeable membrane 8. The Nafion membrane has the property of easily absorbing water from the vapor or liquid phase, and mainly transmits water and hardly transmits hydrogen iodide.
The hydrogen iodide aqueous solution supplied from the Bunsen reactor 2 is supplied to the hydrogen iodide aqueous solution supply chamber 21 of the moisture membrane separator 6 and is subjected to moisture membrane separation by the water selective permeable membrane 8. The water that has permeated through the water selective permeable membrane 8 is evaporated by passing a dry gas through the permeation chamber 23 and exhausted as a wet gas. As a result, the hydrogen iodide aqueous solution is concentrated, and is sent to the distillation tower 24 as a hydrogen iodide concentrate (or gas).

4, the solubility of _{I 2} in hydrogen iodide solutions of _{I 2 (HI-I 2)} is shown.
From the figure, it can be seen that when the temperature of the hydrogen iodide solution is lowered, the solubility of I ₂ is lowered and iodine is further precipitated. For example, in the case of a hydrogen iodide solution having a concentration of I ₂ of 80 wt%, iodine precipitates at around 95 ° C.
In the case of the present embodiment, since the aqueous solution is 11 wt% HI, 81 wt% I ₂ , and 8 wt% H ₂ 0, iodine is precipitated when the temperature is lowered to about 90 ° C., for example. That is, when the water membrane separation operation is performed at room temperature as in Patent Document 1, the temperature of the hydrogen iodide aqueous solution is lowered by the latent heat of vaporization that turns water into water vapor, so that iodine in the hydrogen iodide aqueous solution is precipitated.
Therefore, in this embodiment, heat (for example, about 110 ° C.) for maintaining the temperature above the temperature at which iodine is deposited is supplied to the moisture membrane separation device 6.

Thus, according to the present embodiment, the following operational effects are obtained.
Since the heat supply device 26 supplies heat to the moisture membrane separation device 6 so as to maintain a temperature equal to or higher than the temperature at which iodine is precipitated, the concentration can proceed while preventing the precipitation of iodine.
Furthermore, since the IS process exhaust heat is used as the heat used in the heat supply device 26, the heat energy can be reduced.

  In addition, since the water selective permeable membrane 8 in the moisture membrane separation device 6 is applied and the water in the hydrogen iodide aqueous solution is subjected to membrane separation to concentrate the hydrogen iodide aqueous solution, water and hydrogen iodide. The progress of concentration is not hindered by the azeotropic conditions. Therefore, extra heat energy is not required as compared with the case of concentrating under the azeotropic condition by the distillation method.

Furthermore, by concentrating to a concentration exceeding the azeotropic concentration of about 16 mol% (HI-H ₂ 0) by the water membrane separation device 6, the azeotropic distillation is performed in the distillation column 24 using the IS process exhaust heat as a heat source thereafter. It can be further concentrated without obstructing the progress by the conditions. Therefore, compared with the case where the same concentration range is concentrated by the moisture membrane separator 6, the thermal energy input to the moisture membrane separator 6 can be reduced. Moreover, compared with the case where the same concentration range is concentrated by distillation under an azeotropic condition, the heat energy to be input can be greatly reduced. That is, the thermal energy input to the hydrogen iodide concentration step can be reduced as much as possible, and as a result, the hydrogen production efficiency can be improved.

[Second Embodiment]
Next, a second embodiment of the present invention will be described with reference to FIG.
In addition, this embodiment differs in the structure of the surroundings of the water membrane separator 6 with respect to 1st embodiment. Therefore, only different points from the first embodiment will be described, and the other points are the same as those of the first embodiment, and thus the description thereof will be omitted.
As shown in FIG. 5, an iodine removing device 28 is disposed on the upstream side of the moisture membrane separation device 6.
The iodine removing device 28 is divided into a front chamber 27 and a rear chamber 29 by a wall body 25 standing upward from the bottom surface of the container.
The aqueous hydrogen iodide solution supplied from the Bunsen reactor 2 is supplied to the front chamber 27 of the iodine removing device 28. By cooling the aqueous hydrogen iodide solution to about room temperature with cooling water, the iodine in the aqueous solution is solidified and deposited in the front chamber 27. The cooling water is injected from above in the figure of the iodine removing device 28 as shown by broken line arrows in FIG. 5, and is taken out from below in the figure through a flow path different from the recycle solution.

The precipitated iodine settles downward, and only the supernatant moves over the wall body 25 and moves to the rear chamber 29. Therefore, the aqueous solution in the rear chamber 29 is a hydrogen iodide aqueous solution from which the precipitated iodine is removed. The aqueous hydrogen iodide solution in the rear chamber 29 is sent to the moisture membrane separation device 6. The precipitated iodine is taken out together with a part of the aqueous solution from the lower part of the front chamber 27, sent to the Bunsen reactor 5 (see FIG. 1) by a pump (not shown), and reused as raw water and iodine.
In addition, when seawater can be deposited using seawater as a heat source of the iodine removing device 28, seawater is used as cooling water.

  In the moisture membrane separation device 6, the hydrogen iodide aqueous solution from which the precipitated iodine has been removed in advance is concentrated by moisture membrane separation. For example, an aqueous solution obtained by removing iodine precipitated by cooling an aqueous hydrogen iodide solution to about room temperature does not precipitate iodine even when water membrane separation is performed at room temperature, so that concentration can proceed at room temperature. .

  However, there is a risk that the aqueous hydrogen iodide solution may be cooled to room temperature or lower due to latent heat of evaporation in which water becomes water vapor during moisture membrane separation. Therefore, in order to maintain the temperature of the hydrogen iodide aqueous solution at about room temperature, the heat energy for the latent heat of vaporization is supplied by the heat supplier 26. In the case of the present embodiment, it is sufficient to supply heat energy corresponding to the latent heat of evaporation, so seawater is used as the heat source of the heat supplier 26.

Thus, according to the present embodiment, the following operational effects are obtained.
Since the iodine in the hydrogen iodide aqueous solution is previously removed by the iodine removing device 28, the concentration can proceed at room temperature without precipitation of iodine at the stage of water film separation.
In addition, since the heat of evaporation latent heat that turns water into water vapor is supplied using the heat source of seawater, the heat energy used in the heat supply device 26 can be reduced.
Thereby, compared with the case where it concentrates under azeotropic conditions by the distillation method, the thermal energy supplied can be reduced significantly. That is, the thermal energy input to the hydrogen iodide concentration step can be reduced as much as possible, and as a result, the hydrogen production efficiency can be improved.

The first embodiment and the second embodiment described above can be modified as follows. That is, as shown in FIG. 6, the electrodialyzer 22 is disposed between the water membrane separator 6 and the distillation column 24.
If the concentration of the aqueous hydrogen iodide solution cannot be increased by simply performing the water membrane separation with the water membrane separator 6, the aqueous hydrogen iodide solution is concentrated beyond the azeotropic concentration by using the electrodialyzer 22 as an auxiliary. To do. The hydrogen iodide aqueous solution concentrated to a concentration exceeding the azeotropic concentration is then sent to the distillation column 24 to be further concentrated.
When the hydrogen iodide aqueous solution is sufficiently concentrated by the electrodialyzer 22, the distillation column 24 may be omitted and the hydrogen iodide solution may be sent directly to the hydrogen iodide decomposer 11.

Thus, even when the concentration of the hydrogen iodide aqueous solution does not increase to a concentration exceeding the azeotropic concentration of about 16 mol% (HI-H ₂ 0) with the water membrane separator 6 alone, the electrodialyzer 22 It can be concentrated beyond the azeotropic concentration and then further concentrated in the distillation column 24 using the waste heat of the IS process as a heat source without being hindered by the azeotropic conditions.
Thereby, compared with the case where the same concentration range is concentrated by the water membrane separator 6, the thermal energy input to the water membrane separator 6 can be greatly reduced. That is, the thermal energy input to the hydrogen iodide concentration step can be reduced as much as possible, and as a result, the hydrogen production efficiency can be improved.

[Third embodiment]
Next, a hydrogen production apparatus 30 according to a third embodiment of the present invention will be described with reference to FIGS.
As shown in FIG. 7, in the hydrogen production apparatus 30 according to the present embodiment, the hydrogen iodide purifying and concentrating device 9 is electrically connected to the upstream side of the moisture membrane separation apparatus 6 instead of the iodine removal apparatus 28 of the second embodiment. The second embodiment is different from the second embodiment in that a dialyzer 32 is provided.
In the following, parts having the same configuration as those of the hydrogen production apparatus according to the second embodiment are denoted by the same reference numerals and description thereof is omitted.

The electrodialyzer 32 concentrates the aqueous hydrogen iodide solution supplied from the Bunsen reactor 2 and removes iodine from the aqueous hydrogen iodide solution.
Specifically, the electrodialyzer 32 will be described in detail with reference to FIG.
The electrodialyzer 32 includes a cation exchange membrane 34 that partitions the anode chamber A and the cathode chamber B, an anode 36 installed in the anode chamber A, and a cathode 38 installed in the cathode chamber B.
The electrodialyzer 32 is configured to electrolyze the aqueous hydrogen iodide solution by applying a voltage between the anode 36 and the cathode 38.

The cation exchange membrane 34 selectively transmits cations on the anode chamber A side to the cathode chamber B side.
The anode 36 undergoes an oxidation reaction during electrolysis, and the cathode 38 undergoes a reduction reaction during electrolysis.
As described in the first embodiment, the hydrogen iodide aqueous solution supplied from the Bunsen reactor ₂ also contains iodine (I ₂ ) that has not been reacted in the Bunsen reactor 2. 8, the hydrogen iodide aqueous solution supplied to the electrodialyzer 32 is a HI-I ₂ -H ₂ O mixed solution.

The HI-I ₂ -H ₂ O mixed solution is supplied to the anode chamber A and the cathode chamber B, respectively. When a voltage is applied between the anode 36 and the cathode 38, the HI-I ₂ -H ₂ O mixed solution is electrolyzed and separated by the cation exchange membrane 34. At the anode 36, I ⁻ of ionized HI is oxidized to I ₂ , and at the cathode 38, I ₂ is reduced to I ⁻ . At this time, H ⁺ of ionized HI in the solution in the anode chamber A (hereinafter simply referred to as “anolyte”) permeates through the cation exchange membrane 34, and the solution in the cathode chamber B (hereinafter simply referred to as “cathode”). Move to "Liquid"). This H ⁺ becomes HI by combining with I ⁻ in the catholyte. As a result, in the anolyte, the HI component is diluted and the I ₂ component is concentrated. On the other hand, in the catholyte, the HI component is concentrated and the I ₂ component is diluted.

That is, in the cathode chamber B, the concentration of hydrogen iodide in the hydrogen iodide aqueous solution can be increased, and iodine is removed. This hydrogen iodide aqueous solution is sent to the moisture membrane separator 6.
In the anode chamber A, iodine is generated in a liquid state. This iodine is taken out in a liquid state together with a part of the aqueous solution, and sent to the Bunsen reactor 5 (see FIG. 1) by a pump (not shown).

Returning to FIG. 7, the water membrane separator 6 further concentrates the hydrogen iodide aqueous solution concentrated in the electrodialyzer 32 by water membrane separation. The hydrogen iodide aqueous solution concentrated by the moisture membrane separation device 6 is then sent to the distillation column 24 and further concentrated.
In this case, the hydrogen iodide aqueous solution sent to the distillation column 24 should just be concentrated exceeding azeotropic concentration. For example, the hydrogen iodide aqueous solution may be concentrated to a concentration exceeding the azeotropic concentration by the electrodialyzer 32, or the hydrogen iodide aqueous solution is concentrated to a concentration exceeding the azeotropic concentration by the water membrane separator 6. It is good as well.

The operation of the hydrogen production apparatus 30 according to this embodiment configured as described above will be described.
The aqueous hydrogen iodide solution sent from the Bunsen reactor 2 is first supplied to the electrodialyzer 32. In the electrodialyzer 32, the aqueous hydrogen iodide solution is concentrated and iodine is removed in the cathode chamber B shown in FIG. This aqueous hydrogen iodide solution is taken out from the electrodialyzer 32 and sent to the water membrane separator 6. On the other hand, in the anode chamber A, iodine in a liquid state is generated. This iodine is taken out together with a part of the aqueous solution, sent to a Bunsen reactor 5 (see FIG. 1) as a recycle solution by a pump (not shown), and reused as raw water and iodine. In this case, since the recycling solution contains iodine in a liquid state, solidified iodine does not exist in the recycling solution. Therefore, the recycling solution can be easily used.

  The aqueous hydrogen iodide solution sent from the electrodialyzer 32 to the moisture membrane separation device 6 is further concentrated by moisture membrane separation. Since this aqueous hydrogen iodide solution is concentrated and iodine is removed, iodine does not precipitate even when water membrane separation is performed at room temperature. Therefore, concentration can be further advanced at room temperature.

The concentrated hydrogen iodide aqueous solution is sent to the distillation column 24 by the moisture membrane separator 6.
Since this aqueous hydrogen iodide solution passes through the electrodialyzer 32 and the water membrane separator 6 and is concentrated beyond the azeotropic concentration, the distillation tower 24 does not interfere with the progress due to the azeotropic conditions. Can be further concentrated.
In addition, when the hydrogen iodide aqueous solution sent from the water membrane separator 6 to the distillation column 24 is sufficiently concentrated, a known gas-liquid separator or the like may be used instead of the distillation column 24. Good.

As described above, according to the iodine production apparatus 30 according to the present embodiment, since iodine does not precipitate at the stage of the water membrane separation by the water membrane separator 6, the operating temperature of the water membrane separator 6 can be lowered. it can. Therefore, the thermal energy input to the hydrogen iodide concentration step can be reduced as much as possible, and as a result, the hydrogen production efficiency can be improved.
Furthermore, since the iodine removed from the hydrogen iodide aqueous solution can be used as a recycled solution in a liquid state by the action of the electrodialyzer 32, the recycled solution can be easily used.

In addition, in each embodiment mentioned above, although conditions of pressure and temperature were shown concretely, these are an example to the last, and this invention is not limited to these numerical values.
Further, the number of distillation columns 24 installed on the downstream side of the water membrane separator 6 is not limited to one as in this embodiment, and may be two or more.

It is the schematic block diagram which showed the hydrogen production apparatus concerning 1st embodiment of this invention. It is the schematic which showed the moisture membrane separator periphery of the hydrogen production apparatus concerning 1st embodiment of this invention. It is the schematic of a moisture membrane separator. The solubility of I ₂ of hydrogen iodide solution is a graph showing the relationship of concentration and temperature. It is the schematic which showed the water membrane separation apparatus periphery of the hydrogen production apparatus concerning 2nd embodiment of this invention. It is the schematic which showed the surroundings of the water | moisture-content membrane separator about the modification of each said embodiment of this invention. It is this schematic which shows the hydrogen iodide refinement | concentration concentrator of the hydrogen production apparatus concerning 3rd Embodiment of this invention. It is a figure which shows the electrodialyzer of the hydrogen iodide refinement | purification concentrator of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Hydrogen production device 2 Bunsen reactor 3 Hydrogen iodide concentration cracking device 4 Sulfuric acid concentration cracking device 6 Water membrane separation device 8 Water selective permeable membrane 22 Electrodialyzer 24 Distillation tower 26 Heat supply device 28 Iodine removal device

Claims (11)

A Bunsen reactor for producing an aqueous sulfuric acid solution and an aqueous hydrogen iodide solution from iodine, sulfur dioxide and water;
A hydrogen iodide concentrating and decomposing apparatus for decomposing hydrogen iodide after concentrating the hydrogen iodide aqueous solution obtained by the Bunsen reactor and obtaining hydrogen as a product and iodine to be supplied to the Bunsen reactor;
A sulfuric acid concentration and decomposition apparatus that decomposes sulfuric acid after concentrating the sulfuric acid aqueous solution obtained by the Bunsen reactor, and obtains oxygen and sulfur dioxide to be supplied to the Bunsen reactor.
In the hydrogen production apparatus, the hydrogen iodide concentration and decomposition apparatus is provided with a moisture membrane separation device for separating a hydrogen iodide aqueous solution by a water selective permeable membrane.
The moisture membrane separation device is provided with a heat supply device for supplying heat for maintaining a temperature higher than a temperature at which iodine is precipitated with respect to an aqueous hydrogen iodide solution treated by the water selective permeable membrane. Characteristic hydrogen production equipment.   The hydrogen production apparatus according to claim 1, wherein exhaust heat in the hydrogen production apparatus is used as a heat source of the heat supply unit. A Bunsen reactor for producing an aqueous sulfuric acid solution and an aqueous hydrogen iodide solution from iodine, sulfur dioxide and water;
A hydrogen iodide concentrating and decomposing apparatus for decomposing hydrogen iodide after concentrating the hydrogen iodide aqueous solution obtained by the Bunsen reactor and obtaining hydrogen as a product and iodine to be supplied to the Bunsen reactor;
A sulfuric acid concentration and decomposition apparatus that decomposes sulfuric acid after concentrating the sulfuric acid aqueous solution obtained by the Bunsen reactor, and obtains oxygen and sulfur dioxide to be supplied to the Bunsen reactor.
In the hydrogen production apparatus, the hydrogen iodide concentration and decomposition apparatus is provided with a moisture membrane separation device for separating a hydrogen iodide aqueous solution by a water selective permeable membrane.
On the upstream side of the moisture membrane separator, an iodine removing device for depositing and removing iodine is provided,
2. The hydrogen production apparatus according to claim 1, wherein the moisture membrane separation device is provided with a heat supply device for supplying heat corresponding to latent heat of evaporation to the hydrogen iodide aqueous solution treated by the water selective permeable membrane. A Bunsen reactor for producing an aqueous sulfuric acid solution and an aqueous hydrogen iodide solution from iodine, sulfur dioxide and water;
A hydrogen iodide concentrating and decomposing apparatus for decomposing hydrogen iodide after concentrating the hydrogen iodide aqueous solution obtained by the Bunsen reactor and obtaining hydrogen as a product and iodine to be supplied to the Bunsen reactor;
A sulfuric acid concentration and decomposition apparatus that decomposes sulfuric acid after concentrating the sulfuric acid aqueous solution obtained by the Bunsen reactor, and obtains oxygen and sulfur dioxide to be supplied to the Bunsen reactor.
In the hydrogen production apparatus, the hydrogen iodide concentration and decomposition apparatus is provided with a moisture membrane separation device for separating a hydrogen iodide aqueous solution by a water selective permeable membrane.
An upstream side of the moisture membrane separator is provided with an electrodialyzer for concentrating the hydrogen iodide aqueous solution and removing iodine in the hydrogen iodide aqueous solution,
2. The hydrogen production apparatus according to claim 1, wherein the moisture membrane separation device is provided with a heat supply device for supplying heat corresponding to latent heat of evaporation to the hydrogen iodide aqueous solution treated by the water selective permeable membrane.   The hydrogen production apparatus according to claim 3 or 4, wherein seawater is used as a heat source of the heat supply unit.   The electrodialyzer for concentrating the hydrogen iodide aqueous solution exceeding the azeotropic concentration of the hydrogen iodide aqueous solution is provided on the downstream side of the moisture membrane separation device. The hydrogen production apparatus described in 1.   The distillation column which further concentrates the hydrogen iodide aqueous solution of the density | concentration exceeding the azeotropic density | concentration is provided in the downstream of the said water | moisture-content membrane separator, The Claim 1 characterized by the above-mentioned. Hydrogen production equipment.   The hydrogen production apparatus according to claim 7, wherein exhaust heat in the hydrogen production apparatus is used as a heat source of the distillation column. A Bunsen reaction step for producing an aqueous sulfuric acid solution and an aqueous hydrogen iodide solution from iodine, sulfur dioxide and water;
Hydrogen iodide concentration and decomposition step of decomposing hydrogen iodide after concentrating the hydrogen iodide aqueous solution obtained by the Bunsen reaction step to obtain hydrogen as a product and iodine to be supplied to the Bunsen reaction step;
A sulfuric acid concentration and decomposition step for decomposing sulfuric acid after concentrating the aqueous sulfuric acid solution obtained by the Bunsen reaction step to obtain oxygen and sulfur dioxide to be supplied to the Bunsen reaction step,
In the hydrogen production method, wherein the hydrogen iodide concentration and decomposition step includes a moisture membrane separation step of separating a hydrogen iodide aqueous solution by a moisture selective permeable membrane.
The moisture membrane separation step is provided with a heat supply step for supplying heat for maintaining a temperature equal to or higher than the temperature at which iodine is precipitated, to the hydrogen iodide aqueous solution treated by the water permselective membrane. A hydrogen production method characterized. A Bunsen reaction step for producing an aqueous sulfuric acid solution and an aqueous hydrogen iodide solution from iodine, sulfur dioxide and water;
Hydrogen iodide concentration and decomposition step of decomposing hydrogen iodide after concentrating the hydrogen iodide aqueous solution obtained by the Bunsen reaction step to obtain hydrogen as a product and iodine to be supplied to the Bunsen reaction step;
A sulfuric acid concentration and decomposition step for decomposing sulfuric acid after concentrating the aqueous sulfuric acid solution obtained by the Bunsen reaction step to obtain oxygen and sulfur dioxide to be supplied to the Bunsen reaction step,
In the hydrogen production method, wherein the hydrogen iodide concentration and decomposition step includes a moisture membrane separation step of separating a hydrogen iodide aqueous solution by a moisture selective permeable membrane.
On the upstream side of the moisture membrane separation step, an iodine removal step for depositing and removing iodine is provided,
The method for producing hydrogen according to claim 1, wherein the moisture membrane separation step includes a heat supply step for supplying heat corresponding to latent heat of evaporation to the hydrogen iodide aqueous solution treated by the water selective permeable membrane. A Bunsen reaction step for producing an aqueous sulfuric acid solution and an aqueous hydrogen iodide solution from iodine, sulfur dioxide and water;
Hydrogen iodide concentration and decomposition step of decomposing hydrogen iodide after concentrating the hydrogen iodide aqueous solution obtained by the Bunsen reaction step to obtain hydrogen as a product and iodine to be supplied to the Bunsen reaction step;
A sulfuric acid concentration and decomposition step for decomposing sulfuric acid after concentrating the aqueous sulfuric acid solution obtained by the Bunsen reaction step to obtain oxygen and sulfur dioxide to be supplied to the Bunsen reaction step,
In the hydrogen production method, wherein the hydrogen iodide concentration and decomposition step includes a moisture membrane separation step of separating a hydrogen iodide aqueous solution by a moisture selective permeable membrane.
An upstream side of the moisture membrane separation step is provided with a step of concentrating a hydrogen iodide aqueous solution and a step of removing iodine in the hydrogen iodide aqueous solution,
The method for producing hydrogen according to claim 1, wherein the moisture membrane separation step includes a heat supply step for supplying heat corresponding to latent heat of evaporation to the hydrogen iodide aqueous solution treated by the water selective permeable membrane.

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