JP2008297141A - Hydrogen manufacturing apparatus and method using thermochemical method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hydrogen manufacturing apparatus using a thermochemical method and a method of using the same, in which a hydrogen yield can be increased, while maintaining nearly the same level of the scale of apparatus and heat efficiency required during hydrogen iodide decomposition. <P>SOLUTION: The hydrogen manufacturing apparatus using a thermochemical method includes: a hydrogen iodide generation vessel 3 which generates hydrogen iodide and sulfuric acid 25 by thermochemically decomposing iodine 23, sulfur dioxide 21 and water 22; a hydrogen iodide distillation vessel 4 which separates water 22 from the hydrogen iodide introduced from the vessel 3 where the hydrogen iodide 24 is generated and separated; a hydrogen iodide decomposition vessel 5 which decomposes separated the hydrogen iodide by a chemical reaction with germanium into hydrogen 26 and iodine 23; a hydrogen iodide-iodine recovering vessel 6 which recovers the decomposed iodine 23 and the undecomposed hydrogen iodine 24, a hydrogen purification vessel 7 which purifies the separated hydrogen 26; a sulfuric acid distillation vessel 1 which separates water 22 from sulfuric acid 25 introduced from the vessel 3 where the sulfuric acid 25 is generated and separated; and a sulfuric acid decomposition vessel 2 which decomposes the separated sulfuric acid 25 into sulfuric acid 21 and oxygen 27. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a thermochemical hydrogen production apparatus and method for efficiently decomposing hydrogen iodide generated when thermochemically producing hydrogen.

  As one vision of the future society, the realization of a hydrogen energy society using hydrogen as an energy medium is attracting attention, and several promising hydrogen production methods are known.

  Among several hydrogen production methods, the IS method (Iodine-Sulfur method: a method for producing hydrogen by thermochemically decomposing water while internally circulating iodine and sulfuric acid, SI method) Is known).

  In this IS method, internal circulation through three main processes (Bunsen reaction process, hydrogen iodide concentration and decomposition process, and sulfuric acid concentration and decomposition process) is performed by supplying heat of about 900 ° C obtained from water and power plants. The water is converted into hydrogen and oxygen via In this IS method, a high temperature gas furnace or the like is used as a heat source.

In the Bunsen reaction step, water, iodine and sulfur dioxide are converted into hydrogen iodide (HI) and sulfuric acid (H ₂ SO ₄ ) via a thermochemical process. Next, in the hydrogen iodide concentration and decomposition step, the hydrogen iodide produced in the previous step is decomposed into hydrogen and iodine by heating. The decomposed iodine is circulated to the Bunsen reaction step, and the undecomposed product is recycled to hydrogen iodide concentration or the like. Hydrogen is removed as a product.

  Next, in the sulfuric acid concentration decomposition step, one sulfuric acid produced in the Bunsen reaction step is decomposed into oxygen, water, and sulfur dioxide by heating. The decomposed sulfur dioxide is circulated to the Bunsen reaction step, and the undecomposed product is recycled to the sulfuric acid concentration step. Oxygen is extracted as a product.

  However, in this IS method, since the equilibrium decomposition rate of hydrogen iodide in the hydrogen iodide decomposition step is small, it is difficult to obtain a high hydrogen production rate. For this reason, it is necessary to increase the final decomposition rate by increasing the number of stages of the hydrogen iodide decomposition apparatus, recycling the undecomposed hydrogen iodide, etc., and thus the thermal efficiency is poor. In addition to this method, hydrogen generated by decomposition of hydrogen iodide is removed from the system using a hydrogen permeable membrane, and the decomposition equilibrium is shifted to increase the hydrogen iodide decomposition rate (for example, Non-patent document 1).

In this hydrogen iodide decomposition apparatus, hydrogen iodide gas is brought to a high temperature (about 500 ° C.) and decomposed into iodine and hydrogen in the presence of a catalyst. When iodine or hydrogen which is a decomposition product is removed from the outside of the system, more hydrogen iodide is decomposed and a decomposition product is generated by the law of thermodynamic equilibrium.
Gab-Jin Hwang and Kaoru Onuki, J. et al. Membrane Science, 194 (2001) 207-215

  In the conventional hydrogen iodide decomposer and its decomposition method for the conventional thermochemical hydrogen production described above, the hydrogen decomposition rate is low in the thermal decomposition using a platinum catalyst because the equilibrium decomposition rate of hydrogen iodide is low. For this reason, attempts have been made to increase the final decomposition rate of hydrogen iodide by increasing the number of stages of the decomposition apparatus or recirculating undecomposed hydrogen iodide.

  However, when the decomposition apparatus is multistaged, there are problems that the scale of the apparatus becomes large, the thermal efficiency decreases, the hydrogen production cost increases, and it is difficult to achieve economically.

  Further, the catalyst is poisoned by hydrogen iodide, and there is a problem that it is difficult to obtain a stable performance in the long term.

  Furthermore, in a hydrogen iodide decomposing apparatus using a hydrogen permeable membrane that transfers hydrogen produced by decomposition of hydrogen iodide to the outside of the system, it is necessary to increase the durability of the membrane and high pressure for hydrogen to permeate the membrane. There were problems such as that there was a decrease in the pressure of hydrogen and the product.

  The present invention has been made to solve the above-mentioned problems, and thermochemical hydrogen production that can operate at low pressure and improve the hydrogen production rate while maintaining the same equipment scale and thermal efficiency during decomposition of hydrogen iodide. An object is to provide an apparatus and a method thereof.

  In order to achieve the above object, in the thermochemical hydrogen production apparatus of the present invention, a hydrogen iodide production vessel in which iodine, sulfur dioxide and water are thermochemically decomposed to produce hydrogen iodide and sulfuric acid, and this A hydrogen iodide distillation vessel in which hydrogen iodide produced and separated in a hydrogen iodide production vessel is introduced and water is separated from the hydrogen iodide, and hydrogen iodide separated in the hydrogen iodide distillation vessel is introduced. A hydrogen iodide decomposition vessel that is chemically reacted with germanium filled with hydrogen iodide and decomposed into hydrogen and iodine, and iodine and undecomposed hydrogen iodide decomposed in the hydrogen iodide decomposition vessel are recovered. A hydrogen iodide / iodine recovery vessel, a hydrogen purification vessel for purifying hydrogen decomposed in the hydrogen iodide decomposition vessel, and sulfuric acid produced and separated in the hydrogen iodide production vessel are Sulfuric acid distillation vessel water is separated, the sulfuric acid the separated sulfuric acid distillation vessel is characterized in that it has a sulfuric acid decomposition vessel is decomposed into sulfur dioxide and oxygen.

  In order to achieve the above object, in the thermochemical hydrogen production method of the present invention, a Bunsen reaction step in which iodine, sulfur dioxide and water are decomposed thermochemically to produce hydrogen iodide and sulfuric acid, and this A hydrogen iodide distillation step in which hydrogen iodide produced and separated is introduced and water is separated from the hydrogen iodide, and hydrogen iodide from which the water is separated and charged germanium are chemically reacted to form hydrogen and A hydrogen iodide decomposition step that decomposes into iodine, a hydrogen iodide / iodine recovery step that recovers the decomposed iodine and undecomposed hydrogen iodide, a hydrogen purification step that purifies the separated hydrogen, A sulfuric acid distillation step in which the generated and separated sulfuric acid is introduced and water is separated from the sulfuric acid; and a sulfuric acid decomposition step in which the separated sulfuric acid is decomposed into sulfur dioxide and oxygen. It is an.

  According to the hydrogen iodide decomposer and method of the present invention, hydrogen iodide and germanium are chemically reacted to operate at a low pressure while maintaining the same scale and thermal efficiency of hydrogen iodide decomposition. The hydrogen production rate can be improved.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of a hydrogen iodide decomposer and a decomposition method thereof according to the present invention will be described with reference to the drawings. Here, the same or similar parts are denoted by common reference numerals, and redundant description is omitted.

  FIG. 1 is a configuration diagram showing a thermochemical hydrogen production apparatus according to a first embodiment of the present invention.

  First, the basic configuration of a thermochemical hydrogen production apparatus will be described with reference to FIG.

  As shown in this figure, the thermochemical hydrogen production method by the IS method mainly comprises three steps, namely, a Bunsen reaction step 18, a hydrogen iodide (HI) concentration cracking step 19, and a sulfuric acid concentration cracking step 20. The In each of the above steps, there are these main reactions and reactions that assist them.

First, the Bunsen reaction step 18 will be described. Iodine (I ₂ ) 23 is supplied to the hydrogen iodide production vessel 3 via the iodine supply line 2 c. Similarly, sulfur dioxide (SO ₂ ) 21 is supplied to the hydrogen iodide production vessel 3 via the sulfur dioxide supply line 2a, and water (H ₂ O) 22 is supplied via the water supply line 2b. This hydrogen iodide production vessel 3 is also called a Bunsen reactor.

  In this hydrogen iodide production vessel 3, hydrogen iodide 24 and sulfuric acid 25 are produced from the introduced sulfur dioxide 21, water 22 and iodine 23 by the Bunsen reaction. In this Bunsen reaction step, a reaction represented by the following formula (1) is performed.

SO ₂ + 2H ₂ O + I ₂ → 2HI + H ₂ SO ₄ (1)
Here, by adding an excess of iodine 23, it is separated into a phase mainly composed of sulfuric acid 25 and a phase mainly composed of hydrogen iodide 24 and iodine 23. The hydrogen iodide 24 and iodine 23 in the separated phase containing hydrogen iodide 24 as a main component are introduced into the hydrogen iodide distillation vessel 4 via the hydrogen iodide transfer line 8.

  Next, the HI concentration decomposition step 19 will be described. The hydrogen iodide 24 separated in the Bunsen reaction step 18 is sent to the hydrogen iodide (HI) distillation vessel 4 through the hydrogen iodide transfer line 8 together with the water 22. In the hydrogen iodide distillation vessel 4, water is distilled and separated into hydrogen iodide 24 and iodine 23. The separated hydrogen iodide 24 or the hydrogen iodide 24 containing water vapor is introduced into a hydrogen iodide (HI) decomposition vessel 5.

  The separated iodine 23 is recirculated to the hydrogen iodide production vessel 3 via the distiller-concentrated iodine transfer line 12. The separated hydrogen iodide 24 is introduced into the hydrogen iodide decomposition vessel 5. In the hydrogen iodide decomposition vessel 5, the hydrogen iodide 24 is heated and decomposed into hydrogen 26 and iodine 23. This heating is performed by, for example, a heat source led from a power plant.

  The iodine 23 decomposed in the hydrogen iodide decomposition vessel 5 and the undecomposed hydrogen iodide 24 are introduced into the hydrogen iodide / iodine collection vessel 6 and recovered. The recovered undecomposed hydrogen iodide 24 and the like are returned to the hydrogen iodide distillation vessel 4 through the iodine circulation line 10 and reused for hydrogen production.

  Hydrogen 26 decomposed in the hydrogen iodide decomposition vessel 5 is introduced into the hydrogen purification vessel 7 and purified. The purified hydrogen 26 is recovered as a product via the purified hydrogen outlet line 9. Further, the remaining iodine 23 is circulated to the hydrogen iodide production vessel 3 via the residue circulation line 11 and is reused for hydrogen production.

  Next, the sulfuric acid concentration decomposition step 20 will be described. The upper phase sulfuric acid 25 separated in the Bunsen reaction step 18 is sent into the sulfuric acid evaporation vessel 1 together with the water 22. In the sulfuric acid evaporation container 1, the water 22 is distilled to be concentrated sulfuric acid 25. The sulfuric acid 25 evaporated in the sulfuric acid evaporation container 1 is sent to the sulfuric acid decomposition container 2 to generate sulfur dioxide 21. The sulfur dioxide 21 is sent to the hydrogen iodide production vessel 3 via the sulfur dioxide supply line 2a. Further, water 22 is introduced into the hydrogen iodide production vessel 3 through the water supply line 2b and iodine 23 through the iodine supply line 2c.

  In the embodiment of the present embodiment configured as described above, by supplying heat of about 900 ° C. obtained from water, a power plant or the like, the Bunsen reaction step 18 which is mainly three steps, hydrogen iodide concentration decomposition Hydrogen 26 can be produced from hydrogen iodide 24 through internal circulation by step 19 and sulfuric acid concentration decomposition step 20.

  Next, the hydrogen iodide decomposition vessel 5 will be described with reference to FIG.

  FIG. 2 is a schematic longitudinal sectional view showing the configuration of the hydrogen iodide decomposition vessel 5.

As shown in this figure, the germanium filling portion 5a, which is a hydrogen production means at the lower part of the hydrogen iodide decomposition vessel 5, is filled with germanium (Ge) 28, and the temperature is controlled to 400 ° C. The introduced hydrogen iodide 24 and germanium (Ge) 28 react to generate hydrogen 26 and germanium iodide (GeI ₄ ) 29 as shown by the following equation (2).

Ge + 4HI → 2H ₂ + GeI ₄ (2)
The generated germanium iodide 29 is mainly gas and is transferred together with hydrogen 26 from the germanium filling portion 5a to the germanium iodide holding portion 5b which is germanium iodide holding means on the downstream side. In the germanium iodide holding part 5b, the temperature of the germanium iodide 29 is controlled to be 146 ° C. or lower. Through this germanium iodide holding portion 5 b, germanium iodide 29 becomes solid and is separated from hydrogen 26.

  The separated hydrogen 26, unreacted hydrogen iodide 24 and water 22 are supplied to the hydrogen iodide / iodine recovery vessel 6 shown in FIG. By controlling the temperature of the hydrogen iodide / iodine recovery container 6 to a melting point of 113.6 ° C. or less of the iodine 23, the hydrogen 26 and iodine 23 can be separated. Since the boiling point of the hydrogen iodide 24 is 127 ° C., the hydrogen iodide 24 can also be separated here. The separated and recovered iodine 23 and hydrogen iodide 24 are returned to the hydrogen iodide distillation vessel 4 via the iodine circulation line 10. The separated hydrogen 26 and water 22 are introduced into the hydrogen purification vessel 7. The hydrogen 26 can be purified by lowering the temperature of the hydrogen purification vessel 7. This temperature is desirably a temperature of −42 ° C. or higher at which hydrogen iodide 24 does not become solid.

  Here, regeneration of germanium iodide 29 produced by reacting with hydrogen iodide 24 will be described with reference to FIG.

  FIG. 3 is a schematic longitudinal sectional view for explaining the regeneration reaction of germanium iodide 29 in the hydrogen iodide decomposition vessel 5.

  Regeneration of germanium iodide 29 produced by reacting with hydrogen iodide 24 is performed by the following steps. First, the supply of hydrogen iodide 24 to the hydrogen iodide decomposition vessel 5 is stopped. Next, the temperature of the germanium iodide holding part 5b in the hydrogen iodide decomposition vessel 5 is set to 440 ° C. or higher. The germanium iodide 29 is thermally decomposed and separated into iodine 23 and germanium 28 as shown in the following formula (3). That is, the germanium iodide holding portion 5b functions as germanium iodide holding means and also functions as thermal decomposition means for thermally decomposing germanium iodide 29 into germanium 28 and iodine 23.

GeI ₄ → Ge + 2H ₂ (3)
Further, an inert gas or nitrogen gas 30 is supplied from the regeneration gas supply line 13. The pyrolyzed iodine 23 is returned to the hydrogen iodide production vessel 3 from the regeneration gas outlet line 14 shown in FIG. Thus, germanium iodide 29 is thermally decomposed and germanium 28 and iodine 23 can be reused.

  Next, the relationship between the hydrogen production rate and temperature using germanium 28 according to the embodiment of the present invention will be described with reference to FIG.

  FIG. 4 is a graph showing the relationship between the hydrogen production rate and the temperature using germanium 28 according to the embodiment of the present invention.

  A quartz tube was filled with about 3 to 6 mm of granular or small piece of germanium 28, hydrogen iodide 24 was passed through the quartz tube at a predetermined flow rate, and the hydrogen production rate was obtained as shown in the following equation (4).

Hydrogen production rate (%) = Hydrogen production (NL) / (Supplied hydrogen iodide (NL) / 2)
× 100 (4)
Undecomposed hydrogen iodide 24 and produced iodine 23 were removed by bubbling into a sodium hydroxide solution, and the amount of hydrogen produced was measured with an integrating flow meter. The measurement results are shown in FIG. In addition, SV in a figure has shown the superficial velocity (h <^-1> ), as the following (5) Formula shows.

Superficial velocity (h ⁻¹ ) = hydrogen iodide flow rate (m ³ / hr) / germanium packed body
Product (m ³ ) (5)
As is clear from this figure, at a temperature of 350 ° C., the hydrogen production rate at SV1060 (marked by □) is 10%, the hydrogen production rate at SV1590 (Δ mark) is 15%, and SV530 (◇ The hydrogen production rate at () is 20%. Further, at a temperature of 400 ° C., the hydrogen production rate at SV530 (（mark) is about 60%. From this, it can be seen that the hydrogen production rate is preferably in the range of 350 ° C. or higher, more preferably in the range of 350 to 400 ° C.

Further, at a temperature of 300 ° C., the hydrogen production rate at SV530 (（mark) is 5%. Further, at a temperature of 350 ° C., the hydrogen production rate at SV1060 (□ mark) is 10%, the hydrogen production rate at SV530 (Δ mark) is 15%, and the hydrogen production rate at SV530 (◇ mark). The production rate is 20%. Therefore, superficial velocity, 1000h ^-1 more preferably in the range, it can be seen that 530h ^-1 the range is more preferable.

  The hydrogen production rate was about 21% at 400 ° C. when using a platinum catalyst (thermodynamic equilibrium value), but a hydrogen production rate of 60% was obtained in this embodiment.

  According to the embodiment of the present invention, the hydrogen iodide 24 and the germanium 28 are efficiently reacted to operate at a low pressure while maintaining the same device scale and thermal efficiency when the hydrogen iodide 24 is decomposed. The hydrogen generation rate can be improved.

  FIG. 5 is a schematic longitudinal sectional view for explaining a hydrogen generation reaction and a germanium regeneration reaction in the hydrogen iodide decomposition vessel according to the second embodiment of the present invention.

  In this embodiment, in addition to the first embodiment, an iodine holding unit 5c is provided in the hydrogen iodide decomposition vessel 5, and the same or similar parts as those in FIG. Therefore, redundant explanation is omitted.

As shown in the figure, a germanium filling portion 5 a is provided at the lower part of the hydrogen iodide decomposition vessel 5. The germanium filling portion 5 a is maintained at a temperature of 350 to 400 ° C. at which the hydrogen iodide 24 and the germanium 28 react. The introduced hydrogen iodide 24 and germanium (Ge) 28 react to generate hydrogen 26 and germanium iodide (GeI ₄ ) 29.

  A germanium iodide holding portion 5b is provided on the downstream side of the germanium filling portion 5a. The germanium iodide holding portion 5b is maintained at a temperature of 440 to 500 ° C. at which the germanium iodide 29 is decomposed. Moreover, the iodine holding | maintenance part 5c is provided in the downstream of the germanium iodide holding | maintenance part 5b. This iodine holding part 5c is maintained at a temperature of 114 ° C. to 127 ° C. at which the iodine 23 becomes liquid or solid.

  In the embodiment of the present embodiment configured as described above, the hydrogen iodide decomposition vessel 5 uses a decomposition vessel having three types of temperature regions, that is, a germanium filling portion 5a, a germanium iodide holding portion 5b, and an iodine holding portion 5c. The decomposition of hydrogen iodide 24 is performed. Thereby, hydrogen production by a chemical reaction between hydrogen iodide 24 and germanium 28 and decomposition reaction of the generated germanium iodide 29 can be performed in equilibrium.

  According to the embodiment of the present invention, the hydrogen iodide 24 and the germanium 28 are added while maintaining the balance between the hydrogen production by the chemical reaction of the iodine iodide 24 and the germanium 28 and the decomposition reaction of the generated germanium iodide 29. By efficiently reacting, the hydrogen generation rate can be improved.

  Further, a member having a low reactivity with hydrogen iodide or iodine formed of metal mesh, foamed or fibrous metal, quartz or the like may be installed in the hydrogen iodide decomposition vessel 5. By installing these members in the hydrogen iodide decomposition vessel 5, germanium iodide 29 or iodine 23 can be easily held, and the reaction efficiency can be improved by increasing the temperature uniformity and reaction area. .

  Here, the experimental value of the hydrogen generation amount of the present embodiment will be described with reference to FIG.

  FIG. 6 is a graph showing a comparison between an experimental value and a calculated value of the hydrogen generation amount according to the second embodiment of the present invention.

  In the experiment of the hydrogen production amount of the present embodiment, the test was performed by the same method as that shown in the first embodiment of the present invention in FIG. A comparison between the amount of hydrogen calculated from the change in weight of germanium 28 and the amount of hydrogen actually measured is shown. As is clear from this figure, the hydrogen production amount 1 calculated from the theoretical chemical amount is 1.07, and the hydrogen production amount obtained by the experiment of the present embodiment is 1.07. The This indicates that the produced germanium iodide 29 is decomposed and reused.

  According to the embodiment of the present invention, the hydrogen iodide 24 and the germanium 28 are added while maintaining the balance between the hydrogen production by the chemical reaction of the hydrogen iodide 24 and the germanium 28 and the decomposition reaction of the generated germanium iodide 29. By efficiently reacting, the hydrogen generation rate can be improved.

  FIG. 7 is a block diagram showing a thermochemical hydrogen production apparatus according to the third embodiment of the present invention.

  This figure is provided with two hydrogen iodide decomposition vessels 5 in the thermochemical hydrogen production apparatus of FIG. 1, and the same or similar parts as in FIG. Omitted.

  As shown in this figure, in the thermochemical hydrogen production apparatus shown in FIG. 1, in addition to the hydrogen iodide decomposition vessel 5, as an example, a hydrogen iodide decomposition vessel 5B is arranged in parallel. A regeneration gas supply line 13a and a regeneration gas outlet line 14a are connected to the hydrogen iodide decomposition vessel 5B.

  In the embodiment of the present embodiment configured as described above, germanium 28 filled in the hydrogen iodide decomposition vessel 5 reacts with the hydrogen iodide 24 to produce germanium iodide 29, so that the reacting germanium 28 is reduced. The hydrogen production rate is reduced.

  When the hydrogen production rate of the hydrogen iodide decomposition vessel 5 decreases, the supply of the hydrogen iodide 24 is changed from the hydrogen iodide decomposition vessel 5 to the hydrogen iodide decomposition vessel 5B. An inert gas or nitrogen gas 30 is supplied to the hydrogen iodide decomposition vessel 5 from the regeneration gas supply line 13, and the inside of the vessel is set to a regeneration temperature of 440 ° C. or higher.

  By heating to a regeneration temperature of 440 ° C. or higher, germanium iodide 29 is decomposed into germanium 28 and iodine 23. The decomposed germanium 28 and iodine 23 can be reused. Similarly, when the hydrogen production rate in the hydrogen iodide decomposition vessel 5B decreases, the supply of hydrogen iodide 24 is switched to the hydrogen iodide decomposition vessel 5 in which the regeneration of germanium 28 has been completed.

  According to the embodiment of the present invention, the production of hydrogen 26 and the decomposition of germanium iodide 29 are alternately repeated to continuously decompose hydrogen iodide 24 as a whole, thereby providing hydrogen iodide 24 and germanium. By efficiently reacting 28, the hydrogen production rate can be improved.

  The embodiments of the present invention have been described above. However, the present invention is not limited to the embodiments described above, and departs from the gist of the present invention by combining the configurations of the embodiments. Various modifications can be made without departing from the scope.

The block diagram which shows the thermochemical-method hydrogen production apparatus of the 1st Embodiment of this invention. The schematic longitudinal cross-sectional view which shows the structure of a hydrogen iodide decomposition | disassembly container. The schematic longitudinal cross-sectional view explaining the regeneration reaction of the germanium iodide in a hydrogen iodide decomposition | disassembly container. The graph which shows the relationship between the hydrogen production rate using the germanium of the 1st Embodiment of this invention, and temperature. The schematic longitudinal cross-sectional view explaining the hydrogen-producing reaction in the hydrogen iodide decomposition | disassembly container of the 2nd Embodiment of this invention, and the regeneration reaction of germanium. The graph which shows the comparison with the experimental value and calculated value of the amount of hydrogen production of the 2nd Embodiment of this invention. The block diagram which shows the thermochemical-method hydrogen production apparatus of the 3rd Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Sulfuric acid evaporation container, 2 ... Sulfuric acid decomposition container, 2a ... Sulfur dioxide supply line, 2b ... Water supply line, 2c ... Iodine supply line, 3 ... Hydrogen iodide production | generation container, 4 ... Hydrogen iodide (HI) distillation container, 5, 5B ... Hydrogen iodide (HI) decomposition vessel, 5a ... Germanium filling portion, 5b ... Germanium iodide holding portion, 5c ... Iodine holding portion, 6 ... Hydrogen iodide / iodine recovery vessel, 7 ... Hydrogen purification vessel, 8 ... Hydrogen iodide transfer line, 9 ... Purified hydrogen outlet line, 10 ... Iodine circulation line, 11 ... Residue circulation line, 12 ... Distiller concentrated iodine transfer line, 13, 13a ... Regeneration gas supply line, 14, 14a ... Regeneration gas outlet line, 18 ... Bunsen reaction step, 19 ... hydrogen iodide (HI) concentration decomposition step, 20 ... sulfate concentration decomposition step, 21 ... sulfur dioxide _(SO 2), 22 ... water _(H 2 O), 23 ... iodine _(I 2), 24 ... hydrogen iodide (HI), 25 ... sulfuric _{(H 2 SO 4), 26} ... hydrogen _(H 2), 27 ... oxygen _(O 2), 28 ... germanium (Ge), 29 ... iodide germanium _(GeI 4), 30 ... nitrogen _(N 2).

Claims (9)

A hydrogen iodide production vessel in which iodine, sulfur dioxide and water are thermochemically decomposed to produce hydrogen iodide and sulfuric acid;
A hydrogen iodide distillation vessel in which hydrogen iodide produced and separated in the hydrogen iodide production vessel is introduced and water is separated from the hydrogen iodide;
A hydrogen iodide decomposition vessel in which hydrogen iodide separated in the hydrogen iodide distillation vessel is introduced and reacted with germanium charged with hydrogen iodide to be decomposed into hydrogen and iodine;
A hydrogen iodide / iodine recovery container for recovering iodine decomposed in this hydrogen iodide decomposition container and undecomposed hydrogen iodide;
A hydrogen purification vessel in which hydrogen decomposed in the hydrogen iodide decomposition vessel is purified;
A sulfuric acid distillation vessel in which sulfuric acid produced and separated in the hydrogen iodide production vessel is introduced and water is separated from the sulfuric acid;
A sulfuric acid decomposition vessel in which sulfuric acid separated in the sulfuric acid distillation vessel is decomposed into sulfur dioxide and oxygen;
A thermochemical hydrogen production apparatus characterized by comprising:   2. The hydrogen iodide decomposition vessel comprises a thermal decomposition means for thermally decomposing germanium iodide produced by chemically reacting the germanium and hydrogen iodide into germanium and iodine. The thermochemical hydrogen production apparatus described.   The hydrogen iodide decomposition vessel comprises hydrogen production means for producing hydrogen by a chemical reaction between the hydrogen iodide and germanium, and thermal decomposition means for thermally decomposing the germanium iodide into germanium and iodine. The thermochemical hydrogen production apparatus according to claim 1.   2. The thermochemistry according to claim 1, wherein the hydrogen iodide decomposition vessel comprises germanium iodide holding means for holding germanium iodide produced by a chemical reaction between the germanium and hydrogen iodide. Process hydrogen production equipment.   The thermochemical hydrogen production apparatus according to any one of claims 1 to 4, wherein the hydrogen iodide decomposition vessel is provided with a plurality of reaction vessels for chemically reacting the germanium and hydrogen iodide. . A Bunsen reaction step in which iodine, sulfur dioxide and water are decomposed thermochemically to produce hydrogen iodide and sulfuric acid;
A hydrogen iodide distillation step in which the produced and separated hydrogen iodide is introduced and water is separated from the hydrogen iodide;
A hydrogen iodide decomposition step in which hydrogen iodide from which water is separated and germanium charged are chemically reacted to be decomposed into hydrogen and iodine;
A hydrogen iodide / iodine recovery step for recovering the decomposed iodine and undecomposed hydrogen iodide;
A hydrogen purification step in which the separated hydrogen is purified;
A sulfuric acid distillation step in which the generated and separated sulfuric acid is introduced and water is separated from the sulfuric acid;
A sulfuric acid decomposition step in which the separated sulfuric acid is decomposed into sulfur dioxide and oxygen;
A thermochemical method for producing hydrogen, comprising:   The thermochemical hydrogen production method according to claim 6, wherein in the hydrogen iodide decomposition step, a chemical reaction between the germanium and the hydrogen iodide is performed at a temperature of 350 ° C. or higher. The thermochemical hydrogen production method according to claim 6, wherein in the hydrogen iodide decomposition step, a chemical reaction between the germanium and the hydrogen iodide is performed at a superficial velocity of 1000 h ⁻¹ or less.   In the hydrogen iodide decomposition step, a plurality of reaction vessels for chemically reacting the germanium and hydrogen iodide are provided, and hydrogen production by a chemical reaction of the hydrogen iodide and germanium and a decomposition reaction of the generated germanium iodide are performed. The thermochemical hydrogen production method according to claim 6, wherein hydrogen is produced by carrying out in parallel.

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