JP2006232561A - Apparatus and method for producing hydrogen - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a high purity hydrogen by utilizing a decomposition reaction of hydrogen iodide that is produced by Bunsen reaction to produce hydrogen in a closed cycle, wherein hydrogen iodide in the hydrogen is easily and simply removed without using a large amount of water and without producing a very low temperature condition. <P>SOLUTION: The apparatus for continuously producing hydrogen comprises a hydrogen iodide distillation means (A), a hydrogen iodide decomposition means (B) for decomposing hydrogen iodide obtained through the distillation into hydrogen and iodine, an iodine removal means (C) for obtaining a hydrogen mixture containing hydrogen and residual hydrogen iodide, a hydrogen iodide removal means (D) for separating and obtaining hydrogen and for removing hydrogen iodide in the hydrogen mixture by dissolving the hydrogen iodide into the raw aqueous solution of hydrogen iodide by contacting the hydrogen mixture with the raw aqueous solution of hydrogen iodide, and a hydrogen washing means (E) for washing the separated and obtained hydrogen with water. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an apparatus for continuously producing hydrogen using a decomposition reaction of hydrogen iodide and a method for producing hydrogen.

As a method for producing hydrogen, a method using a decomposition reaction of hydrogen iodide produced by the Bunsen reaction is widely known. This method is a method of obtaining hydrogen by thermally decomposing water in terms of balance, but is composed of the following three reactions.
(Reaction 1) A reaction in which sulfur dioxide gas is absorbed in a mixture of water and iodine to obtain hydrogen iodide and sulfuric acid at a temperature of about 100 ° C. (Bunsen reaction).
(Reaction 2) A reaction in which hydrogen iodide is heated to 400 to 500 ° C. and thermally decomposed to obtain hydrogen and iodine.
(Reaction 3) Reaction in which sulfuric acid is heated to about 850 ° C. and thermally decomposed to obtain water, sulfur dioxide and oxygen.

  In this method, sulfur and iodine compounds (circulating materials) other than water are repeatedly used in the process, and all the reactants can be handled in a gaseous or liquid state. Therefore, there has been proposed a process for producing hydrogen in a closed cycle by using this method while minimizing the wear of the circulating material.

  A schematic diagram of a hydrogen production apparatus applied to such a process is shown in FIG. 31 is a hydrogen iodide distillation tower, 32 is a hydrogen iodide decomposer, 33 is a cooling tower, 34 is a hydrogen washing tower, and 35 is a hydrogen iodide recovery tower.

  In the hydrogen iodide distillation column 31, sulfuric acid is removed from the Bunsen reaction product, and a hydrogen iodide raw material aqueous solution concentrated with hydrogen iodide is distilled by a method such as electrodialysis, so that hydrogen iodide is substantially free of water. Get. The hydrogen iodide aqueous solution of the distillation residue is returned to the hydrogen iodide distillation column 31 again after adjusting the components. The obtained hydrogen iodide substantially free of water is led to the hydrogen iodide decomposer 32 and undergoes thermal decomposition. The thermal decomposition product discharged from the hydrogen iodide decomposer 32 is a mixture of hydrogen, iodine and unreacted hydrogen iodide. Next, this mixture is sent to the cooling tower 33 to be cooled. Then, iodine can be removed and recovered in a state dissolved in hydrogen iodide, while hydrogen is obtained. The recovered iodine hydrogen iodide solution is put into a hydrogen iodide recovery tower 35 to recover hydrogen iodide and iodine. The recovered hydrogen iodide is put into the hydrogen iodide decomposer 32. The recovered iodine is used for the Bunsen reaction. Since hydrogen iodide is mixed in the hydrogen obtained in the cooling tower 33, it is then sent to the hydrogen washing tower 34, and considering the hydrogen iodide removal efficiency, it is about 4 times mol or more of hydrogen iodide. Hydrogen iodide is removed by washing with water, whereby high purity hydrogen is obtained.

  However, in the apparatus shown in FIG. 3, about 53 mol% of hydrogen iodide is mixed in the hydrogen separated in the cooling tower 33, a large amount of washing water must be supplied to the hydrogen washing tower 34. However, if this large amount of water is returned to the hydrogen iodide distillation column 31, there is a problem that the hydrogen iodide concentration of the hydrogen iodide raw material aqueous solution decreases and the load on the distillation column increases.

  For reference, FIG. 4 shows the characteristics of the hydrogen cleaning tower 34 (relationship between the amount of hydrogen iodide loss with respect to the cooling temperature and the amount of cleaning water). In FIG. 4, the amount of HI loss is the amount of hydrogen iodide that could not be recovered with respect to 190.7 kg / h of hydrogen iodide that entered the hydrogen washing tower 34 per hour. FIG. 4 shows that at 40 ° C., hydrogen iodide can hardly be recovered with a washing water amount of 40 kg / h. When the temperature is lowered, the amount of loss is reduced, but not completely removed. It can be seen that at a temperature of 0 to 40 ° C., it is necessary to use a washing water amount of at least 100 to 110 kg / h. However, if this amount of washing water is used, the hydrogen iodide concentration of the hydrogen iodide raw material aqueous solution supplied to the hydrogen iodide distillation column 31 is lowered, and the efficiency of the entire process is deteriorated.

  For this reason, in order not to use washing water to remove hydrogen iodide from hydrogen, the hydrogen washing tower 34 in FIG. 3 is replaced with a new cooling tower 36 (see FIG. 5) that does not use water. Has been tried. The cooling tower 36 can be cooled to a temperature lower than that of the preceding cooling stage 33. FIG. 6 shows the hydrogen iodide condensation and separation characteristics of such a cooling tower. This shows that hydrogen iodide cannot be removed at 20 ° C. or higher. Therefore, in order to sufficiently condense and remove hydrogen iodide, it is necessary to cool to 0 ° C. or lower, but even at −40 ° C., hydrogen iodide cannot be completely removed. Further, when iodine slips from the cooling tower 33 in the previous stage to the cooling tower 36 under such a cryogenic condition, the iodine solidifies in the cooling tower 36 and the cooling tower 36 may be blocked.

Japanese Unexamined Patent Publication No. 2004-232031

  The present invention utilizes the decomposition reaction of hydrogen iodide produced by the Bunsen reaction to minimize the loss of circulating materials, and in the process of producing hydrogen in a closed cycle, without using a large amount of water or at cryogenic conditions. An object is to easily and easily remove hydrogen iodide in hydrogen with less energy without making it, thereby obtaining high-purity hydrogen.

  The inventor should cool the hydrogen iodide decomposition product to remove iodine as a hydrogen iodide solution, and then add the hydrogen mixture of hydrogen and the remaining hydrogen iodide to the hydrogen iodide distillation column. It was found that by washing with a hydrogen iodide raw material aqueous solution, hydrogen iodide in the hydrogen mixture can be dissolved and removed in the hydrogen iodide raw material aqueous solution, whereby the amount of water required for hydrogen cleaning can be greatly reduced. Was completed.

That is, the present invention provides the following steps (1) to (5) in a method for producing hydrogen using a decomposition reaction of hydrogen iodide:
(1) A hydrogen iodide distillation step of distilling a hydrogen iodide raw material aqueous solution containing iodine, hydrogen iodide, and water to separate and obtain hydrogen iodide;
(2) Decomposition composition containing the hydrogen iodide separated in the step (1) [hydrogen iodide distillation step (1)] into hydrogen and iodine, and containing hydrogen, iodine and undecomposed hydrogen iodide Hydrogen iodide decomposition step to obtain a product;
(3) Step (2) The decomposition composition obtained in [hydrogen iodide decomposition step (2)] is cooled, and iodine and hydrogen iodide are removed from the decomposition composition as an iodine-hydrogen iodide solution. And an iodine removal step to obtain a hydrogen mixture containing hydrogen and residual hydrogen iodide;
(4) The hydrogen mixture obtained in step (3) [iodine removal step (3)] should be put into step (1) [hydrogen iodide distillation step (1)], iodine, hydrogen iodide and water. And hydrogen iodide in the hydrogen mixture is dissolved in the hydrogen iodide raw material aqueous solution and removed from the hydrogen mixture, thereby increasing the hydrogen iodide concentration. A hydrogen iodide removing step of obtaining a hydrogen iodide raw material aqueous solution and separating and acquiring hydrogen; and (5) washing the hydrogen separated in step (4) [hydrogen iodide removing step (4)] with water; Provided is a production method having a hydrogen washing step for obtaining purified hydrogen.

Further, the present invention is an apparatus for producing hydrogen using a decomposition reaction of hydrogen iodide, and the following means (A) to (E):
(A) Hydrogen iodide distillation means for separating and obtaining hydrogen iodide by subjecting a hydrogen iodide raw material aqueous solution containing iodine, hydrogen iodide and water to distillation treatment;
(B) Decomposition composition comprising hydrogen iodide supplied from means (A) [hydrogen iodide distillation means (A)] decomposed into hydrogen and iodine, and containing hydrogen, iodine and undecomposed hydrogen iodide Hydrogen iodide decomposition means for obtaining a product;
(C) The decomposition composition obtained by the means (B) [hydrogen iodide decomposition means (B)] is cooled, and the hydrogen iodide and iodine in the decomposition composition are used as an iodine-hydrogen iodide solution. Means for removing iodine from the cracking composition and for obtaining a hydrogen mixture containing hydrogen and residual hydrogen iodide;
(D) Means (C) [iodine removal means (C)] The hydrogen mixture obtained in the means (A) [hydrogen iodide distillation means (A)] should be put into iodine, hydrogen iodide and water And hydrogen iodide in the hydrogen mixture is dissolved in the hydrogen iodide raw material aqueous solution and removed from the hydrogen mixture, thereby increasing the hydrogen iodide concentration. Hydrogen iodide removing means for obtaining a hydrogen iodide raw material aqueous solution and separating and obtaining hydrogen; and (E) Hydrogen obtained by means (D) [hydrogen iodide removing means (D)] is washed with water. And a production apparatus having a hydrogen cleaning means for obtaining purified hydrogen.

  According to the present invention, the hydrogen iodide mixed solution is brought into contact with the hydrogen iodide raw material aqueous solution to be introduced into the hydrogen iodide distillation column, so that an impurity component in hydrogen can be produced without creating a cryogenic condition. The hydrogen iodide can be removed by dissolving it in a hydrogen iodide raw material aqueous solution. Accordingly, the amount of water required for hydrogen cleaning can be drastically reduced, and high-purity hydrogen can be produced continuously.

  As shown in FIG. 1, the apparatus for continuously producing hydrogen according to the present invention comprises hydrogen iodide distillation means (A), hydrogen iodide decomposition means (B), iodine removal means (C), hydrogen iodide. It has removal means (D) and hydrogen cleaning means (E). Furthermore, it is preferable to have a hydrogen iodide recovery means (F). Moreover, it is preferable to have a Bunsen reaction means and a raw material preparation means. These means will be described in detail below.

  In the present invention, the hydrogen iodide distillation means (A) is an apparatus for distilling a hydrogen iodide raw material aqueous solution containing iodine, hydrogen iodide and water, and separating and obtaining hydrogen iodide. Distillation towers can be used. The hydrogen iodide obtained by this means (A) contains substantially no water. Moreover, the mixture containing hydrogen iodide, iodine, and water is obtained as a distillation residue. In addition, in this hydrogen iodide distillation means (A), the hydrogen iodide distillation process (1) mentioned later is implemented. Here, hydrogen iodide substantially free of water means 95 mol% or more of hydrogen iodide.

  The hydrogen iodide decomposition means (B) decomposes hydrogen iodide supplied from the hydrogen iodide distillation means (A) into hydrogen and iodine, and contains hydrogen, iodine and undecomposed hydrogen iodide. It is an apparatus for obtaining the decomposition composition which can be used, A well-known thermal decomposer can be used. In addition, in this hydrogen iodide decomposition | disassembly means (B), the hydrogen iodide decomposition | disassembly process (2) mentioned later is implemented.

  The iodine removal means (C) cools the decomposition composition obtained by the hydrogen iodide decomposition means (B), and decomposes the hydrogen iodide and iodine in the decomposition composition as an iodine-hydrogen iodide solution. It is an apparatus for removing hydrogen from the composition and obtaining a hydrogen mixture containing hydrogen and residual hydrogen iodide, and a known cooler can be used. In this iodine removal means (C), an iodine removal step (3) described later is performed. Moreover, the hydrogen iodide concentration in the hydrogen mixture is preferably as low as possible.

  The hydrogen iodide removing means (D) contains iodine, hydrogen iodide and water to be added to the hydrogen iodide distillation means (A) with the hydrogen mixture obtained by the iodine removing means (C). Hydrogen iodide in the hydrogen mixture is dissolved in the hydrogen iodide source aqueous solution and removed from the hydrogen mixture by contacting with the hydrogen iodide source aqueous solution, whereby hydrogen iodide concentration is increased. This is an apparatus for obtaining a raw material aqueous solution and separating and acquiring hydrogen, and a known gas-liquid contact apparatus can be used. Here, the hydrogen iodide raw material aqueous solution with an increased hydrogen iodide concentration obtained by the hydrogen iodide removing means (D) is introduced into the hydrogen iodide distillation means (A) for circulation use. It is preferable to use a simple apparatus configuration. The means is not particularly limited. In this hydrogen iodide removing means (D), a hydrogen iodide removing step (4) described later is performed.

  The hydrogen washing means (E) is an apparatus for washing the hydrogen obtained by the hydrogen iodide removing means (D) with water to obtain purified hydrogen, and a known hydrogen washing apparatus can be used. In this hydrogen cleaning means (E), a hydrogen cleaning step (5) described later is performed.

  The hydrogen iodide recovery means (F) is an apparatus for recovering iodine as a residue while distilling and recovering hydrogen iodide from the iodine-hydrogen iodide solution obtained by the iodine removal means (C). Here, the hydrogen iodide distilled and recovered by the hydrogen iodide recovery means (F) is used together with the water-free hydrogen iodide separated by the hydrogen iodide distillation means (A) for recycle use. It is preferable to adopt an apparatus configuration that is put into the disassembling means (B). The means is not particularly limited. In this hydrogen iodide recovery means (F), a hydrogen iodide recovery step (6) described later is performed.

  The hydrogen production apparatus of the present invention is a known Bunsen reaction means for reacting iodine recovered by the hydrogen iodide recovery means (F) together with sulfur dioxide and water, such as a bubble column reactor or a stirred tank reactor. And removing the sulfuric acid from the Bunsen reaction product obtained by the Bunsen reaction means, and preparing a hydrogen iodide raw material composition for introduction into the hydrogen iodide removal means (D) from the remaining Bunsen reaction product It is preferable to have a known raw material preparation means such as an electrodialyzer or a membrane separator.

  Next, the manufacturing method of the invention including the following steps (1) to (5) using the manufacturing apparatus of FIG. 1 will be described in detail with reference to FIG.

Hydrogen iodide distillation process (1)
In this step, a hydrogen iodide raw material aqueous solution containing iodine, hydrogen iodide and water is put into the hydrogen iodide distillation means (A) and subjected to distillation treatment, and water-free iodination substantially free of water. Separated into hydrogen and a distillation residue containing hydrogen iodide, iodine and water. That is, the bottom of the distillation column is an azeotrope of hydrogen iodide containing iodine and water, and excess hydrogen iodide is separated from the azeotropic composition. Here, the reason for removing water of hydrogen iodide is that thermal decomposition of hydrogen iodide becomes insufficient if water is present in the decomposition reaction of hydrogen iodide. The hydrogen iodide aqueous solution, which is a distillation residue having a reduced hydrogen iodide concentration, is adjusted to the components and then charged into a hydrogen iodide removal step (4) described later.

  The preferable composition of the hydrogen iodide raw material aqueous solution used in this hydrogen iodide distillation step (1) is 0 to 25 mol% iodine, 15 to 50 mol% hydrogen iodide, and 25 to 85 mol% water. The distillation conditions are preferably a temperature of 40 to 300 ° C. and a pressure of 1 to 3 MPa.

Hydrogen iodide decomposition process (2)
Next, the water-free hydrogen iodide separated in the hydrogen iodide distillation step (1) is sent to the hydrogen iodide decomposition means (B), decomposed into hydrogen and iodine, and the hydrogen, iodine and undecomposed A decomposition composition containing hydrogen iodide is obtained. As the thermal decomposition conditions for hydrogen iodide, known conditions can be adopted, but it is preferable to decompose hydrogen iodide at a pressure of 1 MPa or more, which can be recovered as a liquid with ordinary cooling water (about 40 ° C.). .

Iodine removal step (3)
Next, the decomposition composition obtained in the hydrogen iodide decomposition step (2) is sent to the iodine removing means (C), cooled, and unreacted hydrogen iodide and iodine of the decomposition composition are converted into iodine-iodine. Remove from the decomposition composition as a hydrogen fluoride solution. Thereby, a hydrogen mixture comprising hydrogen and the remaining hydrogen iodide is obtained. Here, the concentration of hydrogen iodide in the hydrogen mixture is preferably as low as possible. The cooling temperature is preferably 20 to 40 ° C., and the pressure is 1 to 3 MPa.

Hydrogen iodide removal step (4)
Next, the hydrogen mixture obtained in the iodine removal step (3) is added to the hydrogen iodide raw material aqueous solution containing iodine, hydrogen iodide and water to be added to the hydrogen iodide distillation step (1). Contact is made in the removing means (D). Thereby, most hydrogen iodide in the hydrogen mixture can be dissolved in the hydrogen iodide raw material aqueous solution and removed. In this case, as shown in FIG. 2 (characteristic diagram of hydrogen iodide removing means (hydrogen iodide absorption tower)), the temperature is preferably 60 ° C. or less, more preferably 40 which can be maintained with normal cooling water. It is preferable to set to about ° C. The pressure is preferably 1 to 3 MPa.

  When hydrogen iodide is absorbed in an aqueous solution, it quickly binds to iodine and water, so that it has a high absorption capacity and dissociates in the solution, resulting in a very low vapor pressure. Therefore, a hydrogen iodide raw material aqueous solution having an increased hydrogen iodide concentration can be obtained, and hydrogen having a significantly reduced hydrogen iodide concentration can be obtained.

  It is preferable to add the hydrogen iodide raw material aqueous solution with an increased hydrogen iodide concentration obtained in this step to the hydrogen iodide distillation step (1) for circulation.

Hydrogen cleaning process (5)
Next, the hydrogen obtained in the hydrogen iodide removing step (4) is introduced into the hydrogen washing means (E) and washed with water. Since the amount of hydrogen iodide is significantly reduced, the amount of water used in this process is significantly less than in the past. The water used for washing is recovered, and highly purified hydrogen separated from the water used for washing is obtained.

  The water recovered in this step is preferably mixed with the distillation residue recovered in the hydrogen iodide distillation step (1).

  In the production method of the present invention, it is preferable to provide the following step (6) [hydrogen iodide recovery step (6)] for circulation use.

Hydrogen iodide recovery process (6)
In this step, the iodine-hydrogen iodide solution obtained in the iodine removal step (3) is guided to a hydrogen iodide recovery means (6), and hydrogen iodide is recovered by distillation and iodine is recovered as a residue.

  The hydrogen iodide distilled and recovered in this step is sent to the hydrogen iodide decomposition means (B) together with the water-free hydrogen iodide separated in the hydrogen iodide distillation step (1), and hydrogen iodide for circulation use. It is preferable to put into the decomposition step (2).

  The iodine recovered in the hydrogen iodide recovery step (6) is subjected to a Bunsen reaction with sulfur dioxide and water, and the resulting Bunsen reaction product is left to stand to remove sulfuric acid in the upper layer, and the remaining lower Bunsen. The reaction product (a ternary mixture of water, iodine and hydrogen iodide, which is in an azeotropic composition with water. The molar ratio of water / hydrogen iodide is about 5.3, iodine / iodine The molar ratio of hydrogen fluoride is about 3.8.) Is preferably concentrated to an azeotropic composition or higher by an appropriate concentration method (for example, electrodialysis). After concentration, it is preferable to add to the hydrogen iodide removing step (4).

  In addition, Table 1 below shows an example of the material balance when the manufacturing method of the present invention is carried out with the manufacturing apparatus of FIG.

  From the results of Table 1, it can be seen that according to the present invention, hydrogen can be washed with a very small amount of water (see stream symbol 112), and the purity of hydrogen is high (see stream symbol 113).

  According to the present invention, a hydrogen iodide raw material aqueous solution to be supplied to a hydrogen iodide distillation column is a hydrogen mixture composed of hydrogen obtained by removing iodine and hydrogen iodide from a hydrogen iodide decomposition reaction product and a small amount of hydrogen iodide. Since hydrogen iodide in hydrogen can be recovered in the hydrogen iodide raw material aqueous solution by bringing it into contact with hydrogen iodide, the amount of hydrogen gas washing water can be significantly reduced, and the load on the hydrogen iodide distillation column that returns the recovered water can be reduced. Can do. Further, since the temperature at the time of recovery of hydrogen iodide is 60 ° C. or less, preferably about 40 ° C., it can be operated by cooling with ordinary cooling water. Furthermore, since the hydrogen iodide concentration of the hydrogen iodide raw material aqueous solution can be increased, it is possible to reduce the load of the hydrogen iodide distillation column to be charged. Therefore, the hydrogen production apparatus and production method of the present invention are very useful for continuous industrial production of hydrogen.

It is the schematic of the manufacturing apparatus of hydrogen of this invention. Characteristic diagram of hydrogen iodide removing means (hydrogen iodide absorption tower) in the present invention It is the schematic of the conventional hydrogen production apparatus. It is a characteristic view of a hydrogen washing tower. It is the schematic of the conventional hydrogen production apparatus. It is a hydrogen iodide condensation-separation characteristic figure of a cooling tower.

Explanation of symbols

A Hydrogen iodide distillation means B Hydrogen iodide decomposition means C Iodine removal means D Hydrogen iodide removal means E Hydrogen cleaning means F Hydrogen iodide recovery means

Claims (10)

In the method for producing hydrogen using the decomposition reaction of hydrogen iodide, the following steps (1) to (5):
(1) A hydrogen iodide distillation step of distilling a hydrogen iodide raw material aqueous solution containing iodine, hydrogen iodide, and water to separate and obtain hydrogen iodide;
(2) The hydrogen iodide decomposition step of decomposing the hydrogen iodide separated in step (1) into hydrogen and iodine to obtain a decomposition composition containing hydrogen, iodine and undecomposed hydrogen iodide;
(3) The decomposition composition obtained in the step (2) is cooled, and iodine and hydrogen iodide are removed from the decomposition composition as an iodine-hydrogen iodide solution, and hydrogen and residual hydrogen iodide are removed. An iodine removal step to obtain a hydrogen mixture containing;
(4) The hydrogen mixture obtained in step (3) is brought into contact with a hydrogen iodide raw material aqueous solution containing iodine, hydrogen iodide and water, which is to be introduced into step (1). Hydrogen iodide is dissolved in the hydrogen iodide raw material aqueous solution and removed from the hydrogen mixture, thereby obtaining a hydrogen iodide raw material aqueous solution having an increased hydrogen iodide concentration, and separating and obtaining hydrogen. And (5) A production method comprising a hydrogen washing step in which the hydrogen separated in step (4) is washed with water to obtain purified hydrogen.   The manufacturing method according to claim 1, wherein the hydrogen iodide raw material aqueous solution with an increased hydrogen iodide concentration obtained in the step (4) is added to the step (1). The following step (6):
(6) The method according to claim 1 or 2, further comprising a step of distilling and recovering hydrogen iodide from the iodine-hydrogen iodide solution obtained in step (3), and further recovering iodine as a residue.   The production method according to claim 3, wherein the hydrogen iodide distilled and recovered in the step (6) is added to the step (2) together with the hydrogen iodide separated in the step (1).   The iodine recovered in step (6) is subjected to a Bunsen reaction with sulfur dioxide and water, sulfuric acid is removed from the resulting Bunsen reaction product, and the remaining Bunsen reaction product is adjusted for components, and then introduced into step (4). The manufacturing method of Claim 1 used as a hydrogen iodide raw material composition. An apparatus for producing hydrogen using a decomposition reaction of hydrogen iodide, comprising the following means (A) to (E):
(A) Hydrogen iodide distillation means for separating and obtaining hydrogen iodide by subjecting a hydrogen iodide raw material aqueous solution containing iodine, hydrogen iodide and water to distillation treatment;
(B) Hydrogen iodide decomposition means for decomposing hydrogen iodide supplied from means (A) into hydrogen and iodine to obtain a decomposition composition containing hydrogen, iodine and undecomposed hydrogen iodide ;
(C) The decomposition composition obtained in the means (B) is cooled, and hydrogen iodide and iodine in the decomposition composition are removed from the decomposition composition as an iodine-hydrogen iodide solution. Means for removing iodine to obtain a hydrogen mixture containing residual hydrogen iodide;
(D) The hydrogen mixture obtained by the means (C) is brought into contact with an aqueous hydrogen iodide raw material solution containing iodine, hydrogen iodide and water to be added to the means (A). The hydrogen iodide contained therein is dissolved in the hydrogen iodide raw material aqueous solution and removed from the hydrogen mixture, thereby obtaining a hydrogen iodide raw material aqueous solution having an increased hydrogen iodide concentration, and an iodine for separating and obtaining hydrogen. And (E) a production apparatus having a hydrogen washing means for washing the hydrogen obtained by the means (D) with water to obtain purified hydrogen.   The manufacturing apparatus according to claim 6, wherein the hydrogen iodide raw material aqueous solution having a high hydrogen iodide concentration obtained by the means (D) is introduced into the means (A). The following means (F):
(F) The hydrogen iodide recovery means for recovering iodine as a residue while distilling and recovering hydrogen iodide from the iodine-hydrogen iodide solution obtained by the means (C). Manufacturing equipment.   9. The production according to claim 8, wherein the hydrogen iodide distilled and recovered by the means (F) is added to the means (B) together with the water-free hydrogen iodide separated by the means (A). apparatus. Bunsen reaction means for reacting iodine recovered by means (F) together with sulfur dioxide and water, sulfuric acid is removed from the Bunsen reaction product obtained by the Bunsen reaction means, and from the remaining Bunsen reaction product, The manufacturing apparatus according to any one of claims 6 to 9, further comprising a raw material preparation means for preparing a hydrogen iodide raw material composition to be charged into the means (D).

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