JP2007290889A - Apparatus and method for producing hydrogen by thermochemical process - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an apparatus and method for producing hydrogen in which reaction control is performed at each step related to hydrogen production by a thermochemical process. <P>SOLUTION: The apparatus for producing hydrogen by the thermochemical process comprises: a Bunsen reactor 1 in which iodine 14, sulfur dioxide 15 and water 11 are thermochemically decomposed to form hydrogen iodide 16 and sulfuric acid 17; a two phase separator for separating the formed hydrogen iodide 16 and sulfuric acid 17; a hydrogen iodide decomposer for decomposing the separated hydrogen iodide 16 into hydrogen and iodine 14; a sulfuric acid decomposer for decomposing the separated sulfuric acid into sulfur dioxide 15, oxygen and water 11; and a reaction control means to control the reaction in at least one device selected from the Bunsen reactor 1, the two phase separator, a hydrogen iodide purifier, a hydrogen iodide concentrator, a hydrogen iodide/iodine distiller, the hydrogen iodide decomposer, a hydrogen iodide/iodine recovery device, a sulfuric acid purifier, a sulfuric acid concentrator, the sulfuric acid decomposer and a sulfuric acid recovery device (e.g., a Bunsen circulation/agitation system 29). <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a thermochemical hydrogen production apparatus and method for controlling a reaction in each step related to hydrogen production by a thermochemical method.

  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, and the SI method) Is known) (see, for example, Patent Document 1).

  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 above Bunsen reaction step, water, iodine, and sulfur dioxide are changed to hydrogen iodide (HI) and sulfuric acid 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 taken out as a product.

Next, in the sulfuric acid concentration decomposition step, one sulfuric acid produced in the Bunsen reaction step is also 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 sulfuric acid concentration or the like. Oxygen is extracted as a product.
JP 2005-41764 A

  In hydrogen production by the conventional thermochemical method described above, there are mainly three main reaction steps (Bunsen reaction step, hydrogen iodide decomposition step, sulfuric acid decomposition step) and up to 10 auxiliary reaction steps (two-phase separation step, Hydrogen iodide purification process, hydrogen iodide concentration process, hydrogen iodide / iodine distillation process, undecomposed hydrogen iodide treatment process, water washing process, sulfuric acid purification process, sulfuric acid concentration process, undecomposed sulfuric acid treatment process, oxygen washing process) It is comprised from the system which combined.

  Since the hydrogen production by the thermochemical method is configured by combining various chemical reactions, in order to generate hydrogen and oxygen, not only the control in each process but also the exchange with other processes, each process There was a problem that it was necessary to reliably control the auxiliary machine.

  Next, the operation state of each process is considered individually. First, in the Bunsen reaction, the reaction is performed as shown in the following formula (1).

SO ₂ + I ₂ + 2H ₂ O → 2HI + H ₂ SO ₄ (1)
Here, sulfur dioxide, iodine and water are reacted to produce hydrogen iodide and sulfuric acid. Sulfur dioxide obtained from the decomposition of sulfuric acid, iodine obtained from the decomposition of hydrogen iodide, and water as fuel are injected while being quantitatively determined. The most important thing in this reaction is that sulfur dioxide and iodine react in equimolar amounts and water in double moles. At this time, sulfur dioxide is a gas, and water and iodine react with a liquid or solid. In order to react sulfur dioxide which is a gas without leaking out of the system, it is necessary to continuously contact iodine of sulfur dioxide or more and water of 2 times or more in a molar ratio.

  Iodine is an indispensable reactant but difficult to handle. This is because iodine has a melting point of 158 ° C. and a boiling point of 185 ° C., and if it is above the boiling point, it is forced to be treated as a gas. If the temperature is raised above the melting point and handled as a liquid, transfer and the like are relatively easy, but if a portion below the melting point occurs, it is very easy to adhere and immediately solidifies. Moreover, it hardly dissolves in water. Moreover, in a solid state, a difficulty arises in transfer. Further, iodine in the liquid gradually vaporizes even in the normal temperature region, and may adhere to and solidify in the pipe, causing an event such as blockage. There was a problem that it was necessary to assemble a Bunsen reaction system in consideration of these matters.

  Moreover, when the produced hydrogen iodide and sulfuric acid exceed a certain concentration, they are separated into two phases due to the difference in specific gravity of both. At this time, there was a difficulty in injecting each medicine (iodine, sulfur dioxide, water) appropriately.

  Next, of the two-phase liquid obtained by the Bunsen reaction, the composition of a solution mainly composed of hydrogen iodide having a heavy specific gravity is mainly composed of hydrogen iodide / iodine and water, and sulfuric acid is mixed as an impurity. The sulfuric acid that becomes an impurity is removed, and the removed sulfuric acid is also reused.

  As the reaction for removing sulfuric acid as an impurity, as shown in the following formula (2), a reaction reverse to the Bunsen reaction or a reaction utilizing a difference in vapor pressure can be considered.

2HI + H ₂ SO ₄ → SO ₂ + I ₂ + 2H ₂ O (2)
Here, it is important to smoothly transfer the subsequent reaction by controlling sulfuric acid as an impurity. Therefore, there has been a problem that it is necessary to constantly monitor the concentration of sulfuric acid in the hydrogen iodide / iodine solution, and to consider the treatment of removed impurities or a countermeasure when a problem occurs.

  The purified hydrogen iodide / iodine is distilled to separate it into hydrogen iodide and iodine. The iodine mixed in the hydrogen iodide or the hydrogen iodide mixed in the iodine not only lowers the operation efficiency but also causes various problems such as solidification of the iodine. For this reason, there has been a problem that it is necessary to take measures against impurity treatment assuming monitoring of the above-mentioned impurity concentration and measures to be taken when impurities are mixed.

  Further, the separated iodine is supplied again to the Bunsen reaction, and one of the undecomposed hydrogen iodide is introduced into a decomposer and decomposed into hydrogen and iodine as products. As described above, the decomposed iodine changes its composition considerably depending on the temperature. For this reason, there is a problem that not only the temperature and pressure are monitored, but also the entire system is affected if a measure such as a response to an abnormality is neglected. Further, the decomposition of hydrogen iodide has problems such as a catalyst for promoting a decomposition reaction, monitoring and processing of decomposition products, extraction and management of generated hydrogen, and handling in the event of a malfunction.

  Further, after hydrogen iodide decomposition, although various compositions change depending on the decomposition efficiency, most of the decomposition products are hydrogen, iodine, undecomposed hydrogen iodide and water. From those obtained with these compositions, hydrogen is washed out and taken out as a product, and others are reused. In this hydrogen cleaning, cleaning with water alone requires special cleaning because the accompanying iodine causes an adverse effect of iodine adhesion. As described above, there is a problem that it is desirable to select a use place according to the concentration ratio of hydrogen iodide, iodine or water.

  Next, of the two-phase liquid obtained by the Bunsen reaction, the solution in which the specific gravity is mainly sulfuric acid is mainly composed of sulfuric acid and water, and hydrogen iodide / iodine is mixed as an impurity. . This impurity hydrogen iodide / iodine is removed, and the removed hydrogen iodide / iodine is also reused.

  As the reaction for removing sulfuric acid as an impurity, as shown in the above formula (2), a reaction opposite to the Bunsen reaction or a reaction utilizing a difference in vapor pressure can be considered.

  Here, it is important to smoothly shift the reaction after the next stage by managing hydrogen iodide / iodine as impurities. As described above, there has been a problem that it is necessary to constantly monitor the concentration of sulfuric acid in the hydrogen iodide / iodine solution, and to take measures for the treatment of the removed impurities or a problem.

  Moreover, since the refined sulfuric acid is dilute sulfuric acid or sulfuric acid containing a large amount of water, a concentration operation is performed to obtain a concentrated sulfuric acid having a high concentration. At this time, sulfuric acid may be decomposed into sulfur trioxide and water depending on the concentration temperature along with water removal. For this purpose, it is necessary to take measures not only to monitor temperature and pressure, but also to monitor the decomposition of sulfur trioxide, and to take measures and processing when it is generated.

  Further, the decomposition of concentrated sulfuric acid has problems such as a catalyst for promoting a decomposition reaction, monitoring and processing of decomposition products, extraction and management of generated hydrogen, and handling in case of malfunction.

  Further, after the sulfuric acid decomposition, various compositions change depending on the decomposition efficiency, but most of the decomposition products are sulfur dioxide and oxygen, undecomposed sulfuric acid and sulfur trioxide, and water. Among those obtained with these compositions, undecomposed sulfuric acid, sulfur trioxide and water are cooled and returned to sulfuric acid, but the separation of sulfur dioxide and oxygen is difficult because they are gases. was there.

  As described above, it is difficult to generate hydrogen and oxygen unless the control in each process, as well as the exchange with other processes and the control of the auxiliary equipment in each process, are performed reliably.

  The present invention has been made in order to solve the above-mentioned problems. In addition to control in each process related to hydrogen production by a thermochemical method, exchange with other processes or control of auxiliary equipment in each process is reliably performed. Accordingly, it is an object of the present invention to provide a hydrogen production apparatus by a thermochemical method and a method thereof capable of efficiently reacting sulfur dioxide which is a gas and iodine which is a liquid or solid substance which is difficult to handle.

  In order to achieve the above object, in the hydrogen production apparatus according to the thermochemical method of the present invention, a Bunsen reactor for thermochemically decomposing iodine, sulfur dioxide and water to produce hydrogen iodide and sulfuric acid, A two-phase separator for separating hydrogen iodide and sulfuric acid, a hydrogen iodide purifier for removing sulfuric acid as an impurity from the separated hydrogen iodide, and hydrogen iodide for concentrating the purified hydrogen iodide A concentrator, a hydrogen iodide / iodine distiller that separates iodine from the concentrated hydrogen iodide, a hydrogen iodide decomposer that decomposes the hydrogen iodide from which iodine has been separated into hydrogen and iodine, and the decomposition A hydrogen iodide / iodine recovery device for recovering the iodine and undecomposed hydrogen iodide, a sulfuric acid purification device for removing hydrogen iodide / iodine as impurities from the separated sulfuric acid, and the purified sulfur A sulfuric acid concentrator that concentrates the concentrated sulfuric acid, a sulfuric acid decomposer that decomposes the concentrated sulfuric acid into sulfur dioxide, oxygen, and water, a sulfuric acid collector that recovers the decomposed sulfur dioxide and undecomposed sulfuric acid, and the Bunsen reaction Vessel, two-phase separator, hydrogen iodide purifier, hydrogen iodide concentrator, hydrogen iodide / iodine distiller, hydrogen iodide decomposer, hydrogen iodide / iodine collector, sulfuric acid purifier, sulfuric acid concentrator, sulfuric acid Reaction control means for controlling the reaction in at least one apparatus selected from a cracker and a sulfuric acid recovery unit.

  In order to achieve the above object, in the hydrogen production method by the thermochemical method of the present invention, a Bunsen reaction step of thermochemically decomposing iodine, sulfuric acid dioxide and water to produce hydrogen iodide and sulfuric acid, A two-phase separation step for separating the produced hydrogen iodide and sulfuric acid, a hydrogen iodide purification step for removing sulfuric acid as an impurity from the separated hydrogen iodide, and an iodine for concentrating the purified hydrogen iodide. A hydrogen iodide concentration step, a hydrogen iodide / iodine distillation step that separates iodine from the concentrated hydrogen iodide, a hydrogen iodide decomposition step that decomposes the hydrogen iodide from which the iodine has been separated into hydrogen and iodine, A hydrogen iodide / iodine recovery step for recovering the decomposed iodine and undecomposed hydrogen iodide, and a sulfuric acid refining process for removing hydrogen iodide / iodine as impurities from the separated sulfuric acid. A sulfuric acid concentration step for concentrating the purified sulfuric acid, a sulfuric acid decomposition step for decomposing the concentrated sulfuric acid into sulfur dioxide, oxygen and water, and a sulfuric acid for recovering the decomposed sulfur dioxide and undecomposed sulfuric acid. Recovery process, Bunsen reaction process, two-phase separation process, hydrogen iodide purification process, hydrogen iodide concentration process, hydrogen iodide / iodine distillation process, hydrogen iodide decomposition process, hydrogen iodide / iodine recovery process, sulfuric acid purification And a reaction control step for controlling a reaction in at least one step selected from a step, a sulfuric acid concentration step, a sulfuric acid decomposition step, and a sulfuric acid recovery step.

  According to the hydrogen production apparatus and method therefor according to the thermochemical method of the present invention, it is difficult to handle gaseous sulfur dioxide and liquid or solid by reliably performing reaction control in each step relating to hydrogen production by the thermochemical method. It is possible to efficiently react with iodine, which is a new substance.

  Embodiments of a hydrogen production apparatus by a thermochemical method and a method thereof according to the present invention will be described below 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 schematic configuration of a Bunsen reaction step in hydrogen production by a thermochemical method according to an embodiment of the present invention, and FIG. 2 shows basic steps of a hydrogen production method by a thermochemical method of the present invention. FIG.

  First, the basic steps of the hydrogen production method 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 ) 14, sulfur dioxide (SO ₂ ) 15, and water 11 are supplied to the Bunsen reactor 1. In the Bunsen reactor 1, a thermochemical reaction called a Bunsen reaction is generated to generate hydrogen iodide (HI) 16 and sulfuric acid 17.

  The produced hydrogen iodide 16 and sulfuric acid 17 are introduced into the two-phase separator 2. In the two-phase separator 2, hydrogen iodide 16 and sulfuric acid 17 are separated due to the difference in specific gravity. The separated hydrogen iodide 16 and sulfuric acid 17 are sent to the HI concentration decomposition step 19 and the sulfuric acid concentration decomposition step 20, respectively. Unreacted iodine 14, sulfur dioxide 15 and water 11 are separated by the generator in the two-phase separator 2 and returned to the original Bunsen reaction vessel 1.

  Next, the HI concentration decomposition step 19 will be described. The hydrogen iodide 16 separated in the Bunsen reaction step 18 is sent to the HI concentrator 4 through the HI purifier 3 together with the water 11. The sulfuric acid 17 which is an impurity separated by the HI purifier 3 is recycled to the Bunsen reactor 1.

  In the HI concentrator 4, the concentration of the hydrogen iodide 16 is increased by heating. This heating is performed by, for example, a heater 21 using a heat source led from a power plant. The water 11 distilled here is recycled to the Bunsen reaction step 18.

The hydrogen iodide 16 concentrated by the heating is sent to the HI decomposer 6 via the HI / I ₂ still 5. In the HI / I ₂ still 5, hydrogen iodide 16 and iodine 14 are separated. The separated iodine 14 is recycled to the Bunsen reactor 1, and hydrogen iodide 16 is introduced into the HI decomposer 6. In the HI decomposer 6, the hydrogen iodide 16 is decomposed into hydrogen 12 and iodine 14 by being heated. This heating is performed by, for example, a heater 21 using a heat source led from a power plant. However, the rate of decomposition of the hydrogen iodide 16 is about 20% of the hydrogen iodide 16 introduced by the equilibrium of the decomposition product. Therefore, undecomposed hydrogen iodide 16 and water 11 are accompanied by hydrogen 12 and iodine 14 from the outlet of the HI decomposer 6.

  The decomposed hydrogen 12 and iodine 14 are fed into the HI and iodine collector 10 together with undecomposed hydrogen iodide 16. In the HI and iodine recovery unit 10, the hydrogen 12 is recovered by being cooled by the cooler 46. The recovered iodine 14 is recycled to the Bunsen reactor 1.

  The recovered hydrogen 12 is introduced into a hydrogen cleaner 24 and cleaned. Thus, the washed hydrogen 12 is removed as a product.

  Next, the sulfuric acid concentration decomposition step 20 will be described. The sulfuric acid 17 separated by the two-phase separator 2 is sent together with the water 11 to the sulfuric acid concentrator 8 via the sulfuric acid purifier 7. Hydrogen iodide 16 and iodine 14 which are impurities separated by the sulfuric acid purifier 7 are recycled to the Bunsen reactor 1.

  In the sulfuric acid concentrator 8, the concentration of the sulfuric acid 17 is increased by heating. This heating is performed by, for example, a heater 21 using a heat source led from a power plant. The water 11 distilled here is recycled to the Bunsen reactor 1.

  The heated and concentrated sulfuric acid 17 is sent to the sulfuric acid decomposer 23. In the sulfuric acid decomposer 23, the sulfuric acid 17 is heated and decomposed to generate sulfur dioxide 15 and oxygen 13. Alternatively, the sulfuric acid 17 is decomposed by heating to produce sulfur trioxide 22 and water 11. The generated sulfur trioxide 22 is further heated to generate sulfur dioxide 15 and oxygen 13. Although this decomposition depends on the reaction temperature, it is about 80% of the introduced sulfuric acid. Therefore, undecomposed sulfuric acid 17 and water 11 accompany the sulfur dioxide 15 and oxygen 13 from the outlet of the sulfuric acid decomposer 23. .

  The sulfur dioxide 15, sulfur trioxide 22, oxygen 13 and water 11 generated as described above are sent to the sulfuric acid collector 9. In the sulfuric acid recovery unit 9, the sulfur dioxide 15 is recovered and returned to the original Bunsen reactor 1. Unreacted sulfuric acid 17 is recycled to the sulfuric acid decomposer 23. However, in the recovery of the oxygen 13, since it is not easy to separate the gases simultaneously with the sulfur dioxide 15 which is a gas, the oxygen 13 is taken out after being recirculated to the Bunsen reaction step 18 and reacting only the sulfur dioxide 15. It becomes. The recovered oxygen 13 is introduced into an oxygen scrubber 25 and cleaned.

  The configuration of the thermochemical hydrogen production apparatus based on the IS method is a basic configuration for realizing the present embodiment, and in some cases, each apparatus may be divided into two stages to configure the reaction process. .

  For example, the sulfuric acid decomposer 23 does not directly generate the sulfur dioxide 15 from the sulfuric acid 17, but decomposes the sulfuric acid 17 to generate water 11 and sulfur trioxide 22. Thereafter, the sulfur trioxide 22 may be decomposed to form a device in two stages in which sulfur dioxide 15 and oxygen 13 are generated. However, since these reaction steps are generally performed in the sulfuric acid decomposer 23, it can be considered as an equipment configuration having the same function.

  Here, the reaction control in the Bunsen reaction step 18 will be described.

  In the Bunsen reactor 1 described above, sulfur dioxide 15 obtained from the decomposition of water 11 and sulfuric acid 17 as fuel is used as a gas, and iodine 14 obtained from the decomposition of hydrogen iodide 16 is used as a liquid. Thus, in the Bunsen reaction, the reaction between gas and liquid must be controlled.

  For this reason, in the Bunsen reaction step 18, the gas-liquid reaction is carried out 100%. Therefore, not only temperature control including heating of each liquid feeding and reaction vessel 21 by the heater 21 and cooling by the cooler 46 is performed. The reaction is promoted by installing and pressure control. Here, since the sulfur dioxide 15 is a gas, when 100% does not react in the Bunsen reaction step 18, there is a possibility that the sulfur dioxide 15 will be scattered in the same manner as the oxygen 13.

  As a countermeasure, as shown in FIG. 1, a Bunsen circulation / stirring system 29 is provided at the bottom of the Bunsen reactor 1. This Bunsen circulation / stirring system 29 is provided with a circulation pump 28 and a stirrer 30 in the bypass pipe disposed in the Bunsen reactor 1 and circulates to perform stirring.

  In the present embodiment, the sulfur dioxide 15 can be efficiently reacted by ventilating the sulfur dioxide 15 introduced from the sulfuric acid concentration and decomposition step 20 through the gate valve 33 into the Bunsen circulation / stirring system 29. Become. Thus, the thermochemical reaction between a gas and a liquid that are difficult to react in the Bunsen reaction step is promoted, and hydrogen iodide (HI) 16 and sulfuric acid 17 are efficiently generated.

  Further, when the Bunsen reaction in the Bunsen reaction step 18 proceeds, hydrogen iodide 16 and sulfuric acid 17 are produced and separated into two phases in the two-phase separator 2 shown in FIG.

  As described above, by providing the Bunsen circulation / stirring system 29 in the lower part of the Bunsen reactor 1, the Bunsen circulation / stirring is mainly composed of a solution of hydrogen iodide and iodine having a large specific gravity even in a state where two phases are separated. Since it circulates in the system | strain 29, it becomes possible to make the sulfur dioxide 15 react more efficiently.

  In addition, a sulfuric acid / iodine / hydrogen iodide measuring system 40 can be installed in the Bunsen circulation / stirring system 29 via a gate valve 33. In this sulfuric acid / iodine / hydrogen iodide measuring system 40, the raw materials and products in the Bunsen reaction step 18 can be confirmed by ion chromatography or the like.

  Further, the operating temperature of the Bunsen reactor 1 is measured using a thermometer 32. Further, the concentration of hydrogen iodide 16 and iodine 14 is measured in the sulfuric acid / iodine / hydrogen iodide measuring system 40. Based on these measured values, the optimum injection amounts of water 11 and iodine 14 injected into the Bunsen reactor 1 can be controlled.

  In the Bunsen reaction step 18, the sulfur dioxide 15, iodine 14 and water 11 react at a molar ratio of 1: 1: 2 as described above. Among these, since sulfur dioxide 15 is a gas, it is desirable to react a large amount of iodine 14 and water 11 from the viewpoint of preventing the sulfur dioxide from being released out of the system.

  Further, iodine 14 changes the amount of dissolution depending on the concentration of hydrogen iodide 16 present in the solution and the reaction temperature. For example, when the temperature is room temperature, 2 mol of iodine 14 is dissolved per 1 mol of hydrogen iodide 16. When this temperature is about 80 ° C., 3 mol or more of iodine 14 is dissolved with respect to 1 mol of hydrogen iodide 16. When iodine 14 is injected more than this, it may solidify at a temperature equal to or lower than the melting point of iodine 14 to cause clogging of the piping or the like. As described above, it is possible to determine the injection amount of iodine 14 and the injection amount of water 11 filled in the Bunsen reactor 1 from the reaction temperature and the concentrations of hydrogen iodide 16 and iodine 14.

  Further, in the Bunsen reactor 1, the liquid level described later is continuously performed, thereby quantifying the amount of the solution and applying the stirring effect of a stirrer or the like in an optimum state. However, in a state where the two-phase separation is not reached in the middle of the reaction process, it is necessary to cope with an increase in volume due to the injection of the reactive agent. In such a case, the solution is monitored to stop the liquid feeding to the subsequent stage. In other words, the reaction can be reliably controlled by transferring the solution to the Bunsen reaction auxiliary device 57.

  In addition, the gas after the reaction in the Bunsen reactor 1 is transferred to the iodine scrubber 26 at the top. To the iodine cleaner 26, the iodine 14 sublimated together with the heated oxygen 13 is transferred. The iodine 14 having a low temperature adheres and solidifies in the iodine cleaning device 26.

  An iodine cleaning circulator 27 is provided in order to clean the iodine 14 adhered and solidified via the circulation pump 28. The iodine cleaning circulator 27 stores a dilute hydrogen iodide 38 that circulates closed to clean the iodine 14.

  Further, an iodine cleaning container diluted hydrogen iodide storage 37 is provided in the iodine cleaning device 26 in order to store the circulating diluted hydrogen iodide 38. Thus, by providing the iodine cleaning container diluted hydrogen iodide reservoir 37, the sublimated iodine 14 can be efficiently cleaned.

  Furthermore, the hydrogen iodide 16 from the outlet of the circulation pump 28 and the water 11 as the fuel are injected into the iodine scrubber 26, thereby adjusting the concentration of the hydrogen iodide 16 and replenishing the water 11 as the fuel at the same time. Making it possible.

  The iodine scrubber 26 is provided with a sulfur dioxide measuring system 35 via a gate valve 33. By providing this sulfur dioxide measuring system 35, unreacted sulfur dioxide 15 can be monitored. When the sulfur dioxide 15 flows out, the gate valve 33a is closed, and the sulfur dioxide remover 36 is processed in the sulfur dioxide remover 36 through the gate valve 33b.

  In the present embodiment, the oxygen 13 obtained by treating the sulfur dioxide 15 in the sulfur dioxide remover 36 is led out to the oxygen scrubber 25 via the gate valve 33c and the gas transfer pump 58. Thus, it is possible to reduce the emission of harmful sulfur dioxide 15.

  In the present embodiment configured as described above, when the unreacted sulfur dioxide is detected in the sulfur dioxide measuring system 35, the pressure in the Bunsen reactor 1, the iodine scrubber 26, etc. is controlled by the pressure regulating valve 34. It is possible to control.

  According to the present embodiment, this pressure control greatly affects the Bunsen reaction step 18. The Bunsen reaction step 18 is a reaction of sulfur dioxide 15, iodine 14 and water 11. When this reaction is considered as an elementary reaction, the sulfur dioxide 15 reacts with water 11 to form sulfur trioxide water containing sulfur trioxide 22 and then reacts with iodine 14. In this reaction, it was confirmed experimentally that the reaction between the sulfur dioxide 15 and the water 11 is sensitive to the pressure and reacts quantitatively according to the pressure. This indicates that the treatment for the unreacted sulfur dioxide 15 can be ensured by controlling the pressure.

  According to the present embodiment, it is possible to efficiently control sulfur dioxide as a gas and iodine as a difficult-to-handle substance that is liquid or solid by reliably performing control in the Bunsen reaction step related to hydrogen production by a thermochemical method. Can be reacted. Thus, hydrogen can be efficiently generated by reliably performing control in the Bunsen reaction process related to hydrogen production by a thermochemical method.

  FIG. 3 is a configuration diagram showing a schematic configuration of a two-phase separation step in hydrogen production by a thermochemical method according to an embodiment of the present invention. In this figure, a two-phase separator 2 is provided on the upstream side of the Bunsen reactor 1 in FIG. 1, and the same or similar parts as in FIG. .

  As shown in this figure, the two-phase separation liquid produced in the Bunsen reactor 1 can be once transferred to another container and then separated, but here, the Bunsen reactor 1 is separated. It shows about the process of using and isolate | separating a two-phase liquid. The Bunsen reactor 1 is provided with a liquid level / interface detector 41. The liquid level / interface detector 41 monitors the interface of the two-phase liquid in the reaction liquid, solidified iodine in the solution, and the liquid level of the entire solution by ultrasonic waves or the like. Further, the two-phase separation is started without stopping the Bunsen reaction step 18 of FIG. 2 from the time when the interface of the two-phase liquid is detected by the liquid surface / interface detector 41.

  In the Bunsen circulation / stirring system 29, a solution of hydrogen iodide 16 / iodine 14, which is a two-phase liquid, is circulated through a sampling port provided at the bottom of the Bunsen reactor 1, whereby sulfur dioxide 15 And reacts efficiently.

  Moreover, by injecting iodine 14 from the upper part of the Bunsen reactor 1, it is reacted with sulfur dioxide 15 which may remain in the two-phase light liquid. Moreover, when this iodine 14 is inject | poured as a solution from the property, what was hold | maintained at the temperature of 150 degreeC or more is inject | poured. This two-phase light liquid is transferred from the pipe above the two-phase interface of the Bunsen reactor 1 through a gate valve 33d to the two-phase separated light liquid container 2b using a gravity drop or a dedicated transfer pump (not shown). Do it.

  Also, the two-phase heavy liquid is transferred from the piping at the bottom of the Bunsen reactor 1 to the two-phase separated heavy liquid container 2a by a gate valve 33e using a gravity drop or a dedicated transfer pump (not shown). At this time, the liquid level / interface detector 41 monitors the liquid level / interface, measures the temperature with the thermometer 32, and measures the pressure with the pressure gauge 31, so that even if an abnormality occurs, it can be quickly performed. It becomes possible to deal with it.

  Further, a Bunsen reaction auxiliary device 57 is provided via a gate valve 33 f and a liquid transfer pump 44 interposed in the solution transfer pipe disposed at the two-phase interface of the Bunsen reactor 1. In this Bunsen reaction auxiliary device 57, the optimal reaction state can be maintained by performing the liquid level control based on the information monitored by the liquid level / interface detector 41.

  According to the present embodiment, by efficiently performing control in the two-phase separation process for hydrogen production by a thermochemical method, sulfur dioxide that is a gas and iodine that is a liquid or solid material that is difficult to handle are efficiently produced. Can be reacted. Thus, hydrogen can be efficiently generated by reliably performing reaction control in the two-phase separation process related to hydrogen production by a thermochemical method.

  FIG. 4 is a configuration diagram showing a schematic configuration of a hydrogen iodide purification step in hydrogen production by a thermochemical method according to the embodiment of the present invention. In this figure, a hydrogen iodide (HI) purification vessel 3 is provided on the upstream side of the Bunsen reactor 1 in FIG. 1, and the same or similar parts as in FIG. Description is omitted.

  As shown in this figure, sulfuric acid 17 is mixed as an impurity in the heavy liquid mainly composed of hydrogen iodide 16 / iodine 14 in the two-phase layer separation liquid obtained in the Bunsen reactor 1. In order to remove the sulfuric acid 17 as an impurity, a hydrogen iodide purifier 3 is installed.

  As this impurity removal method, there are a reverse Bunsen method and a vapor pressure separation method. This impurity removal method will be described below.

  Of the two-phase separated liquid, a heavy liquid mainly composed of hydrogen iodide 16 / iodine 14 is stored in the two-phase separated heavy liquid container 2a. The heavy liquid mainly composed of hydrogen iodide 16 / iodine 14 stored in the two-phase separated heavy liquid container 2a is introduced into the hydrogen iodide purifier 3. In the hydrogen iodide purifier 3, the purified aqueous solution of hydrogen iodide 16 / iodine 14 is led out to the hydrogen iodide concentrator 4, and the sulfuric acid 17 which is an impurity is led out to the purified impurity container 42.

  In this hydrogen iodide purifier 3, control of the inflow rate of the purified solution, speed control of the purifying carrier gas 43 from the purifying carrier gas container 43a, temperature measurement based on the thermometer 32 of the hydrogen iodide purifier 3, and Pressure adjustment is performed by the pressure adjustment valves 34a and 34b. Purification is possible by controlling the discharged solution and gas velocity using the pressure adjusted in this way.

  The temperature control in the hydrogen iodide refining vessel 3 is preferably two-stage heating control in which the upper / lower individual heating is performed or three-stage heating control in which the upper / middle / lower individual heating is performed.

  In the present embodiment configured as described above, a part of the hydrogen iodide purification solution led out to the hydrogen iodide concentrator 4 is led out to the sulfuric acid / iodine / hydrogen iodide measuring system 40 via the gate valve 33. Is done. By performing composition analysis in the sulfuric acid / iodine / hydrogen iodide measuring system 40, the sulfuric acid 17 flowing as impurities is monitored.

  According to the present embodiment, when the mixing of the sulfuric acid 17 is recognized, the purification solution inflow speed described above is reduced, and the exhaust gas is adjusted by adjusting the speed of the purification carrier gas 43 and the pressure by the pressure regulating valve 34b. By increasing the speed, sulfuric acid 17 as an impurity can be efficiently removed.

  On the other hand, gaseous sulfuric acid 17 or sulfur dioxide 15 that is emitted as impurities in the hydrogen iodide purifier 3 is cooled in the purified impurity container 42. The sulfuric acid 17 containing a large amount of moisture is led out to the Bunsen reaction vessel 1 by the solution transfer pump 44 as a solution.

  In the purified impurity container 42, a sulfur dioxide measuring system 35 is connected via a gate valve 33g to monitor the sulfur dioxide 15 in the purified impurities. When this sulfur dioxide 15 is detected, the gate valve 33h is opened and discharged to the sulfur dioxide injection system in the Bunsen reaction vessel 1 via the gas recovery unit 45. By providing this step, it is possible to reuse the sulfur dioxide 15 obtained by the reverse Bunsen reaction without wasting it.

  According to the present embodiment, it is possible to reliably control gaseous sulfur dioxide and liquid or solid iodine that is difficult to handle by reliably performing control in the hydrogen iodide purification process related to hydrogen production by a thermochemical method. It can be made to react efficiently. Thus, hydrogen can be efficiently generated by reliably performing reaction control in the hydrogen iodide purification process related to hydrogen production by a thermochemical method.

  FIG. 5 is a configuration diagram showing a schematic configuration of a hydrogen iodide concentration step in hydrogen production by a thermochemical method according to an embodiment of the present invention. In this figure, a hydrogen iodide (HI) concentrator 4 is provided on the upstream side of the hydrogen iodide (HI) purifier 3 of FIG. 4, and the same or similar parts as in FIG. A duplicate description will be omitted.

As shown in the figure, the hydrogen iodide 16 / iodine 14 and the water 11 from which impurities have been removed by the hydrogen iodide purifier 3 are led to the hydrogen iodide concentrator 4. In the hydrogen iodide concentrator 4, the introduced hydrogen iodide 16 / iodine 14 and water 11 are concentrated mainly for removing water. Examples of the concentration method include concentration by heating, electrodialysis, and membrane separation. The hydrogen iodide 16 / iodine 14 concentrated by these concentration methods is sent to the hydrogen iodide (HI) / iodine (I ₂ ) distillation vessel 5 by the solution transfer pump 44.

  On the other hand, the water vapor 11 discharged from the hydrogen iodide concentrator 4 is led to the water recovery container 47. In the water recovery container 47, the introduced water vapor 11 is cooled and then led out to the Bunsen reactor 1 through the solution transfer pump 44 and reused.

  In this embodiment configured as described above, the water recovery container 47 is connected to the sulfuric acid / iodine / hydrogen iodide measuring system 40 via the gate valve 33i. The sulfuric acid / iodine / hydrogen iodide measuring system 40 monitors impurities in water. When impurities are detected, the gate valve 33j is closed. At the same time, the gate valve 33k is opened and returned to the hydrogen iodide purification vessel 3 via the solution transfer pump 44, and the purification operation is performed again. When sulfuric acid 17 is detected as an impurity other than moisture, the sulfuric acid 17 is led to a purified impurity container 42 shown in FIG. This configuration enables efficient operation.

  According to the present embodiment, by performing control in the hydrogen iodide concentration step related to hydrogen production by a thermochemical method, sulfur dioxide that is a gas and iodine that is a liquid or solid material that is difficult to handle are obtained. The reaction can be ensured. Thus, hydrogen can be generated efficiently by reliably performing reaction control in the hydrogen iodide concentration step related to hydrogen production by a thermochemical method.

  FIG. 6 is a configuration diagram showing a schematic configuration of a hydrogen iodide / iodine distillation step in hydrogen production by a thermochemical method according to an embodiment of the present invention. In this figure, a hydrogen iodide / iodine distiller 5 is provided on the upstream side of the hydrogen iodide (HI) concentration vessel 4 in FIG. 5, and the same or similar parts as in FIG. Therefore, the duplicate description is omitted.

  As shown in the figure, the hydrogen iodide 16 / iodine 14 concentrated by the hydrogen iodide concentrator 4 is introduced into the hydrogen iodide / iodine distiller 5. This hydrogen iodide 16 / iodine 14 forms polyhydroiodic acid (HIx x = 2 to 10 or more) and is in a form in which hydrogen iodide 16 and iodine 14 coexist, and is separated by distillation. This separation method utilizes the difference in boiling point between hydrogen iodide 16 / iodine 14. For this reason, the temperature control in the hydrogen iodide / iodine distiller 5 is preferably two-stage heating control in which the upper / lower individual heating is performed, or three-stage heating control in which the upper / middle / lower individual heating is performed.

  The temperature of the upper or middle portion of the hydrogen iodide / iodine distiller 5 is controlled to be not less than the boiling point of hydrogen iodide 16 and not more than the boiling point of iodine 14. The lower part of the hydrogen iodide / iodine distiller 5 has a temperature higher than that of the upper / middle part and performs temperature control immediately before the iodine 14 is vaporized. By controlling the temperature in this way, the hydrogen iodide 16 having a low boiling point in the hydrogen iodide / iodine distillation vessel 5 is transferred to the hydrogen iodide decomposition vessel 6 through the gate valve 33l.

  On the other hand, iodine 14 having a high boiling point is introduced into iodine collector 10 through gate valve 33m. The iodine 14 stored in the iodine collector 10 is transferred to the iodine reboiler container 49 by the solution transfer pump 44a. In the iodine reboiler container 49, a small amount of hydrogen iodide 16 that may be contained in the solution is led out to the hydrogen iodide / iodine distiller 5 through the gate valve 33. The iodine 14 is transferred to the Bunsen reactor 1 by the solution pump 44a.

  As described above, the amount of iodine 14 injected into the Bunsen reactor 1 needs to be reliably controlled. For this reason, the iodine 14 obtained as a surplus is returned to the iodine collector 10 by the solution transfer pump 44b. By providing this process, the supply of iodine 14 to the Bunsen reactor 1 can be ensured.

  According to the present embodiment, it is possible to reliably control sulfur dioxide as a gas and iodine as a liquid or solid substance that is difficult to handle by reliably performing control in a hydrogen iodide / iodine distillation process related to hydrogen production by a thermochemical method. Can be reacted reliably. Thus, hydrogen can be efficiently generated by reliably performing reaction control in the hydrogen iodide / iodine distillation step related to hydrogen production by a thermochemical method.

  FIG. 7 is a configuration diagram showing a schematic configuration of a hydrogen iodide decomposition step in hydrogen production by a thermochemical method according to an embodiment of the present invention. In this figure, a hydrogen iodide decomposer 6 is provided on the upstream side of the hydrogen iodide / iodine distiller 5 in FIG. 6, and the same or similar parts as in FIG. Duplicate explanation is omitted.

  As shown in this figure, the hydrogen iodide 16 obtained by the hydrogen iodide / iodine distiller 5 is introduced into the hydrogen iodide decomposer 6. In this hydrogen iodide decomposer 6, hydrogen iodide 16 is decomposed into iodine 14 and hydrogen 12 by the filled catalyst. By using a platinum catalyst as a catalyst used for the decomposition of hydrogen iodide 16, it was experimentally confirmed that the decomposition was performed at a temperature of 400 ° C. with an efficiency of 21%.

  The container structure in the hydrogen iodide decomposer 6 is such that the catalyst is charged to about 1/2 to 2/3 of the container amount on the outlet side of the decomposition container. In order to evaporate the hydrogen iodide 16 on the inlet side or to prevent condensation, a hollow heating section is provided. In order to increase the thermal efficiency in this heating section, it is also effective to fill with a filler (glass or quartz) that does not react with the hydrogen iodide 16 at all.

  Further, the temperature control in the hydrogen iodide decomposition vessel 6 is desirably two-stage heating control for individually heating the upper / lower part or three-stage heating control for individually heating the upper / middle / lower part. The temperature of the inlet side of the hydrogen iodide decomposer 6 is set to about the intermediate temperature between the hydrogen iodide decomposition temperature and the hydrogen iodide boiling point temperature, and the hydrogen iodide 16 is evaporated. In the catalyst filling portion, the temperature of the hydrogen iodide 16 can be efficiently decomposed by controlling the temperature with the decomposition temperature. The gas at 400 ° C. after decomposition is decomposed hydrogen 12, iodine 14 and undecomposed hydrogen iodide 16.

  The decomposed gas at 400 ° C. is introduced into the undecomposed hydrogen iodide recovery device 50. In this undecomposed hydrogen iodide recovery device 50, it is cooled to about 120 ° C. and separated into a gas and a liquid. A cooler 46 is connected to the undecomposed hydrogen iodide recovery device 50 via a gate valve 33n. The solution cooled to room temperature from the cooler 46 is introduced into the sulfuric acid / iodine / hydrogen iodide measuring system 40. In the sulfuric acid / iodine / hydrogen iodide measuring system 40, the concentrations of hydrogen iodide 16 and iodine 14 in the solution are measured. From this measured value, the decomposition efficiency of the catalyst in the decomposition portion of the hydrogen iodide 16 can be obtained, and compared with the hydrogen iodide decomposition efficiency with respect to the temperature obtained experimentally, it is possible to obtain a criterion for determining the catalyst life.

  According to the present embodiment, by performing control in the hydrogen iodide decomposition step related to hydrogen production by a thermochemical method, sulfur dioxide that is a gas and iodine that is a liquid or solid material that is difficult to handle are obtained. The reaction can be ensured. Thus, hydrogen can be efficiently generated by reliably performing reaction control in the hydrogen iodide decomposition step related to hydrogen production by a thermochemical method.

  FIG. 8 is a configuration diagram showing a schematic configuration of a hydrogen recovery and utilization process in hydrogen production by a thermochemical method according to an embodiment of the present invention. In this figure, an undecomposed hydrogen iodide recovery unit 50 is provided on the upstream side of the hydrogen iodide decomposer 6 in FIG. 7, and the same or similar parts as in FIG. Duplicate explanation is omitted.

  As shown in this figure, the gas at 400 ° C. after being decomposed in the hydrogen iodide decomposer 6 is decomposed hydrogen 12, iodine 14, and undecomposed hydrogen iodide 16. The 400 ° C. gas after decomposition in the hydrogen iodide decomposer 6 is introduced into the undecomposed hydrogen iodide recovery device 50 through the gate valve 33p.

  This undecomposed hydrogen iodide 16 is led to the hydrogen iodide / iodine distiller 5 via the solution transfer pump 44. In the hydrogen iodide / iodine distiller 5, the hydrogen iodide 16 is returned to the distillation step and reused. A part of the hydrogen iodide 16 is used as a diluted hydrogen iodide 38 as a cleaning solution of the iodine cleaning device 26 disposed on the upper part of the Bunsen reactor 1 shown in FIG.

  For this purpose, the temperature of the undecomposed hydrogen iodide recovery device 50 is controlled to 120 ° C. Most of the undecomposed hydrogen iodide 16 and the decomposition product iodine 14 are returned as a reflux liquid for distillation in the hydrogen iodide / iodine distillation vessel 5 via the gate valve 33q and the solution transfer pump 44.

  Further, since the control temperature of the undecomposed hydrogen iodide recovery unit 50 is 120 ° C., the hydrogen iodide 16 having a water and solution concentration of about 10% is led to the hydrogen scrubber 24 as a gas. In the hydrogen scrubber 24, the water 11 containing about 10% hydrogen iodide 16 cooled to room temperature passes through the gate valve 33 and the solution transfer pump 44 to the iodine scrubber 27 shown in FIG. Derived. In the iodine cleaning circulator 27, the iodine cleaning diluted hydrogen iodide 38 is used for iodine cleaning.

  Further, the hydrogen 12 recovered as a gas in the undecomposed hydrogen iodide recovery unit 50 is led out to the hydrogen scrubber 24 through the gate valve 33s. The washed hydrogen 12 is metered and managed by the hydrogen flow meter 60, and then is led out to the hydrogen recovery container 51 and delivered as a product.

  According to the present embodiment, sulfur dioxide as a gas and iodine that is a liquid or solid substance that is difficult to handle by reliably performing control in an undecomposed hydrogen iodide recovery step related to hydrogen production by a thermochemical method. Can be reacted reliably. Thus, hydrogen can be efficiently generated by reliably performing reaction control in the undecomposed hydrogen iodide recovery step for hydrogen production by a thermochemical method.

  FIG. 9 is a configuration diagram showing a schematic configuration of a sulfuric acid purification step in hydrogen production by a thermochemical method according to the embodiment of the present invention. In this figure, a sulfuric acid purifier 7 is provided on the upstream side of the Bunsen reactor 1 in FIG. 1, and the same or similar parts as in FIG.

  As shown in the figure, hydrogen iodide 16 / iodine 14 is mixed as an impurity in a light liquid mainly composed of sulfuric acid 17 in the two-phase separation liquid obtained in the Bunsen reactor 1. In order to remove hydrogen iodide 16 / iodine 14 as impurities, a sulfuric acid purifier 7 is installed.

  As this impurity removal method, there are a reverse Bunsen method and a vapor pressure separation method. This impurity removal method will be described below.

  Of the two-phase separated liquid, the light liquid mainly composed of sulfuric acid 17 is stored in the two-phase separated light liquid container 2b. A light liquid mainly composed of sulfuric acid 17 stored in the two-phase separated heavy liquid container 2 b is introduced into the sulfuric acid purification container 7. In this sulfuric acid purification vessel 7, the aqueous solution of sulfuric acid 17 is led out to the sulfuric acid concentration vessel 8, and the impurities hydrogen iodide 16 / iodine 14 are led out to the purification impurity vessel 54.

  At this time, in the sulfuric acid purifier 7, the pressure adjustment is performed while measuring the flow rate of the purified solution, the speed of the purifying carrier gas 53 from the purifying carrier gas container 53 a, and the temperature by the thermometer 32 in the sulfuric acid purifier 7. The pressure is adjusted by the valve 34c. Purification is made possible by controlling the discharged solution and the gas velocity using this adjusted pressure.

  The temperature control in the sulfuric acid purifier 7 is preferably two-stage heating control for individually heating the upper / lower part, or three-stage heating control for individually heating the upper / middle / lower part.

  The purified sulfuric acid purification solution 17 is introduced into the sulfuric acid concentrator 8. A part of the derived sulfuric acid purification solution 17 is sent to the sulfuric acid / iodine / hydrogen iodide measuring system 40. By performing composition analysis in this sulfuric acid / iodine / hydrogen iodide measuring system 40, the hydrogen iodide 16 / iodine 14 introduced as impurities is monitored. At this time, when mixing of hydrogen iodide 16 / iodine 14 is recognized, the purification solution inflow rate is decreased, and the pressure is adjusted by the speed of the purification carrier gas 53 and the pressure regulating valve 34d. It has been experimentally confirmed that hydrogen iodide 16 / iodine 14 as impurities can be removed by reducing the exhaust gas velocity using this adjusted pressure.

  On the other hand, gaseous sulfur dioxide 15 generated as an impurity in the sulfuric acid purifier 7 is led to the purified impurity container 54. In the purified impurity container 54, the hydrogen iodide 16 / iodine 14 which is cooled by the cooler 46 and contains a large amount of water is led out as a solution to the Bunsen reaction container 1 via the solution transfer pump 44.

  In the purified impurity container 54, a sulfur dioxide measuring system 35 is connected via a gate valve 33. In the sulfur dioxide measuring system 35, the sulfur dioxide 15 in the purified impurities is monitored. When the sulfur dioxide 15 is detected, the gate valve 33e is opened and introduced into the gas recovery unit 45. The sulfur dioxide 15 stored in the recovery unit 45 is discharged to a sulfur dioxide injection system in the Bunsen reactor 1 through a gas transfer pump 58.

  According to the present embodiment, it is possible to efficiently control sulfur dioxide as a gas and iodine as a difficult-to-handle substance that is a liquid or solid by reliably performing control in a sulfuric acid purification process related to hydrogen production by a thermochemical method. Can be reacted. Thus, hydrogen can be efficiently generated by reliably performing reaction control in the sulfuric acid purification step related to hydrogen production by a thermochemical method.

  Further, in the sulfuric acid purification step, it is possible to efficiently reuse the sulfur dioxide 15 obtained by the reverse Bunsen reaction.

  FIG. 10 is a configuration diagram showing a schematic configuration of a sulfuric acid concentration step in hydrogen production by a thermochemical method according to an embodiment of the present invention. In this figure, a sulfuric acid concentrator 8 is provided on the upstream side of the sulfuric acid purifier 7 of FIG. 9, and the same or similar parts as in FIG.

  As shown in the figure, the sulfuric acid 17 from which impurities have been removed by the sulfuric acid purifier 7 is sent to the sulfuric acid concentrator 8. In the sulfuric acid concentrator 8, concentration mainly for removing water is performed. In this concentration method, concentration by heating is generally performed. The temperature control in the sulfuric acid concentrator 8 is preferably two-stage heating control in which the upper / lower individual heating is performed, or three-stage heating control in which the upper / middle / lower individual heating is performed. The concentration of sulfuric acid 17 is concentrated to 98% or more by controlling the temperature on the inlet side of the sulfuric acid concentrator 8 between the boiling point of sulfuric acid and the temperature of the solution and controlling it at about 340 ° C. above the boiling point of sulfuric acid at the concentration outlet. Is possible. The concentrated sulfuric acid 17 is led to the sulfuric acid decomposer 23 via the solution transfer pump 44.

  On the other hand, the water discharged from the sulfuric acid concentration vessel 8 is introduced into the concentration impurity vessel 54. The discharged water cooled in the concentrated impurity container 54 is led to the Bunsen reactor 1 through the solution transfer pump 44 and reused. In the concentrated impurity container 54, a sulfuric acid / iodine / hydrogen iodide measuring system 40 is connected via a gate valve 33. The sulfuric acid / iodine / hydrogen iodide measuring system 40 monitors impurities in the water. When this impurity is detected, the gate valve 33f is closed and returned to the sulfuric acid purifier 7 via the gate valve 33g via the solution transfer pump 44 and the purification operation is performed again.

  According to the present embodiment, by efficiently performing control in the sulfuric acid concentration step related to hydrogen production by a thermochemical method, sulfur dioxide that is a gas and iodine that is a liquid or solid material that is difficult to handle are efficiently produced. Can be reacted. Thus, efficient operation is enabled by reliably performing control in the sulfuric acid concentration step related to hydrogen production by the thermochemical method.

  FIG. 11 is a configuration diagram showing a schematic configuration of a sulfuric acid decomposition step in hydrogen production by a thermochemical method according to an embodiment of the present invention. In this figure, a sulfuric acid decomposer 23 is provided on the upstream side of the sulfuric acid concentrator 8 of FIG. 10, and the same or similar parts as in FIG.

  As shown in the figure, the concentrated sulfuric acid 17 obtained by the sulfuric acid concentrator 8 is introduced into the sulfuric acid decomposer 23. The introduced concentrated sulfuric acid 17 is decomposed into oxygen 13 and sulfur dioxide 15 by the catalyst charged in the sulfuric acid decomposer 23. It has been experimentally confirmed that by using a platinum catalyst as a catalyst used for this sulfuric acid decomposition, concentrated sulfuric acid 17 can be decomposed at an efficiency of 80% or higher at a temperature of 900 ° C. or higher.

  The container structure in the sulfuric acid decomposer 23 will be described. The catalyst on the outlet side of the sulfuric acid decomposer 23 is filled with about 1/2 to 2/3 of the total amount of the container. In order to evaporate the sulfuric acid 17 or prevent condensation on the inlet side of the sulfuric acid decomposer 23, a hollow heating unit is provided. In order to increase the thermal efficiency in this heating section, it is also effective to fill with a filler (glass or quartz) that does not react with sulfuric acid 17 at all.

  The temperature control in the sulfuric acid decomposer 23 is preferably two-stage heating control for individually heating the upper / lower parts or three-stage heating control for individually heating the upper / middle / lower parts. The temperature on the inlet side of the sulfuric acid decomposer 23 is controlled to be equal to or higher than the sulfuric acid evaporation temperature, and the temperature of the catalyst packed portion is controlled at the decomposition temperature, thereby enabling efficient decomposition of the sulfuric acid 17.

  The 900 ° C. gas after the decomposition of the sulfuric acid 17 is composed of decomposed oxygen 13, sulfur dioxide 15 and undecomposed sulfuric acid 17. This gas is introduced into the sulfuric acid recovery device 9, cooled to room temperature, and separated into a gas and a liquid.

  In the sulfuric acid recovery device 9, a sulfuric acid / iodine / hydrogen iodide measuring system 40 is connected via a gate valve 33. This sulfuric acid / iodine / hydrogen iodide measuring system 40 measures the concentration of undecomposed sulfuric acid 17 in the solution. From the concentration measurement result of the sulfuric acid 17 and the sulfuric acid speed by the solution transfer pump 44, the decomposition efficiency of the catalyst in the sulfuric acid decomposer 23 is calculated, and compared with the sulfuric acid decomposition efficiency with respect to the temperature obtained experimentally, the catalyst life is judged. It is possible to calculate the standard.

  Note that sulfur dioxide 15 and oxygen 13 as gases in the sulfuric acid recovery unit 9 are vented to the Bunsen circulation / stirring system 29 shown in FIG. The sulfur dioxide 15 and oxygen 13 are supplied to the Bunsen reactor 1 through the Bunsen circulation / stirring system 29. The oxygen 13 is metered and managed by the oxygen flow meter 62 via the oxygen scrubber 25 and then stored as a product in the oxygen recovery container 63.

  According to the present embodiment, it is possible to reliably control sulfur dioxide as a gas and iodine as a difficult-to-handle substance that is a liquid or a solid by reliably performing control in a sulfuric acid decomposition process related to hydrogen production by a thermochemical method. Can be reacted. Thus, hydrogen can be efficiently generated by reliably performing reaction control in the sulfuric acid decomposition step related to hydrogen production by a thermochemical method.

  Furthermore, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention by combining the embodiments of the present invention. it can.

The block diagram which shows schematic structure of the Bunsen reaction process in the hydrogen production by the thermochemical method of embodiment of this invention. The block diagram which shows the fundamental process of the hydrogen production by the thermochemical method of this invention. The block diagram which shows schematic structure of the two-phase separation process in the hydrogen production by the thermochemical method of embodiment of this invention. The block diagram which shows schematic structure of the hydrogen iodide refinement | purification process in the hydrogen production by the thermochemical method of embodiment of this invention. The block diagram which shows schematic structure of the hydrogen iodide concentration process in the hydrogen production by the thermochemical method of embodiment of this invention. The block diagram which shows schematic structure of the hydrogen iodide / iodine distillation process in the hydrogen production by the thermochemical method of embodiment of this invention. The block diagram which shows schematic structure of the hydrogen iodide decomposition | disassembly process in the hydrogen production by the thermochemical method of embodiment of this invention. The block diagram which shows schematic structure of the hydrogen collection | recovery utilization process in the hydrogen production by the thermochemical method of embodiment of this invention. The block diagram which shows schematic structure of the sulfuric acid refinement | purification process in the hydrogen production by the thermochemical method of embodiment of this invention. The block diagram which shows schematic structure of the sulfuric acid concentration process in the hydrogen production by the thermochemical method of embodiment of this invention. The block diagram which shows schematic structure of the sulfuric acid decomposition | disassembly process in the hydrogen production by the thermochemical method of embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Bunsen reactor, 2 ... Two phase separator, 2a ... Two phase separation heavy liquid container, 2b ... Two phase separation light liquid container, 3 ... Hydrogen iodide (HI) refiner, 4 ... Hydrogen iodide (HI) Concentrator, 5 ... HI / I ₂ still, 6 ... Hydrogen iodide (HI) decomposer, 7 ... Sulfuric acid refiner, 8 ... Sulfuric acid concentrator, 9 ... Sulfuric acid collector, 10 ... HI and iodine collector, 11 ... water, 12 ... hydrogen, 13 ... oxygen, 14 ... iodine _(I 2), 15 ... sulfur dioxide _(SO 2), 16 ... hydrogen iodide (HI), 17 ... sulfate, 18 ... Bunsen reaction step, 19 ... iodide Hydrogen HI concentration and decomposition step, 20 ... sulfuric acid concentration and decomposition step, 21 ... heater, 22 ... sulfur trioxide, 23 ... sulfuric acid decomposer, 24 ... hydrogen cleaner, 25 ... oxygen cleaner, 26 ... iodine cleaner, 27 ... iodine circulator, 28 ... circulation pump, 29 ... Bunsen circulation / stirring system, 30 ... Stirrer, 31 ... pressure gauge, 32 ... thermometer, 33 ... gate valve, 34 ... pressure regulating valve, 35 ... sulfur dioxide measuring system, 40 ... sulfuric acid / iodine / hydrogen iodide measuring system, 41 ... liquid level / interface detection , 42 ... Purified impurity container, 43 ... Hydrogen iodide purification carrier gas, 43a ... Hydrogen iodide purification carrier gas container, 44 ... Solution transfer pump, 45 ... Gas recovery device, 46 ... Cooler, 47 ... Water recovery Container: 50 ... Undecomposed hydrogen iodide collector, 51 ... Hydrogen recovery container, 53 ... Carrier gas for purifying sulfuric acid, 54 ... Purified impurity container, 55 ... Carrier gas for sulfuric acid concentration, 56 ... Carrier gas for sulfuric acid decomposition, 57 ... Bunsen reaction auxiliary, 58 ... gas transfer pump, 59 ... carrier gas for distillation, 60 ... hydrogen flow meter, 62 ... oxygen flow meter, 63 ... oxygen recovery container.

Claims (12)

A Bunsen reactor that thermochemically decomposes iodine, sulfur dioxide and water to produce hydrogen iodide and sulfuric acid;
A two-phase separator for separating the produced hydrogen iodide and sulfuric acid;
A hydrogen iodide purifier for removing sulfuric acid as an impurity from the separated hydrogen iodide;
A hydrogen iodide concentrator for concentrating the purified hydrogen iodide;
A hydrogen iodide / iodine distiller to separate iodine from the concentrated hydrogen iodide;
A hydrogen iodide decomposer that decomposes hydrogen iodide from which iodine has been separated into hydrogen and iodine;
A hydrogen iodide / iodine collector for recovering the decomposed iodine and undecomposed hydrogen iodide;
A sulfuric acid purifier for removing hydrogen iodide / iodine as impurities from the separated sulfuric acid;
A sulfuric acid concentrator for concentrating the purified sulfuric acid;
A sulfuric acid decomposer that decomposes the concentrated sulfuric acid into sulfur dioxide, oxygen, and water;
A sulfuric acid recovery unit for recovering the decomposed sulfur dioxide and undecomposed sulfuric acid;
Bunsen reactor, two-phase separator, hydrogen iodide purifier, hydrogen iodide concentrator, hydrogen iodide / iodine distiller, hydrogen iodide decomposer, hydrogen iodide / iodine collector, sulfuric acid purifier, sulfuric acid concentration Reaction control means for controlling the reaction in at least one device selected from a reactor, a sulfuric acid decomposer, and a sulfuric acid recovery device;
A thermochemical hydrogen production apparatus comprising:   The reaction control means in the Bunsen reactor comprises a Bunsen circulation / stirring system provided in the Bunsen reactor via a bypass pipe for circulating and stirring the iodine, sulfuric acid dioxide and water. 1. The thermochemical hydrogen production apparatus according to 1.   The reaction control means in the two-phase separator is a two-phase separation heavy liquid container for storing a hydrogen iodide / iodine solution, which is a heavy liquid of the two-phase liquid, provided in the two-phase separator via a gate valve. And a two-phase separation light liquid container for storing a sulfuric acid solution which is a light liquid of the two-phase liquid.   The reaction control means in the hydrogen iodide purifier comprises a purified impurity container that is provided in the hydrogen iodide purifier via a gate valve and stores sulfuric acid that is the removed impurity. Item 2. The thermochemical hydrogen production apparatus according to item 1.   The thermochemical hydrogen production apparatus according to claim 1, wherein the reaction control means in the hydrogen iodide concentrator comprises a water recovery container for storing water vapor discharged from the hydrogen iodide concentration container.   The reaction control means in the hydrogen iodide / iodine distiller comprises an iodine recovery container that is provided in the hydrogen iodide / iodine distiller via a gate valve and stores iodine separated by distillation. The thermochemical hydrogen production apparatus according to claim 1.   The reaction control means in the hydrogen iodide decomposer includes an undecomposed hydrogen iodide recovery device that is provided in the hydrogen iodide decomposer via a gate valve and stores the decomposed hydrogen, iodine, and undecomposed hydrogen iodide. The thermochemical hydrogen production apparatus according to claim 1, comprising:   2. The thermochemical hydrogen production apparatus according to claim 1, wherein the reaction control means in the hydrogen iodide / iodine recovery unit comprises a hydrogen cleaning unit for cleaning the decomposed hydrogen.   The reaction control means in the sulfuric acid purifier comprises a purified impurity container provided in the sulfuric acid purifier via a gate valve for storing hydrogen iodide / iodine as the removed impurities. Item 2. The thermochemical hydrogen production apparatus according to item 1.   The thermochemical hydrogen production apparatus according to claim 1, wherein the reaction control means in the sulfuric acid concentrator comprises a concentrated impurity container for storing water discharged from the sulfuric acid concentration container.   2. The thermochemical hydrogen production apparatus according to claim 1, wherein the reaction control means in the sulfuric acid decomposing unit comprises a sulfuric acid cleaning unit for cleaning the decomposed oxygen. A Bunsen reaction step in which iodine, sulfur dioxide and water are decomposed thermochemically to produce hydrogen iodide and sulfuric acid;
A two-phase separation step for separating the produced hydrogen iodide and sulfuric acid;
A hydrogen iodide purification step for removing sulfuric acid, which is an impurity, from the separated hydrogen iodide;
A hydrogen iodide concentration step for concentrating the purified hydrogen iodide;
A hydrogen iodide / iodine distillation step to separate iodine from the concentrated hydrogen iodide;
A hydrogen iodide decomposition step of decomposing hydrogen iodide from which iodine is separated into hydrogen and iodine;
A hydrogen iodide / iodine recovery step for recovering the decomposed iodine and undecomposed hydrogen iodide;
A sulfuric acid purification step for removing hydrogen iodide / iodine as impurities from the separated sulfuric acid;
A sulfuric acid concentration step of concentrating the purified sulfuric acid;
A sulfuric acid decomposition step of decomposing the concentrated sulfuric acid into sulfur dioxide, oxygen and water;
A sulfuric acid recovery step for recovering the decomposed sulfur dioxide and undecomposed sulfuric acid;
Bunsen reaction step, two-phase separation step, hydrogen iodide purification step, hydrogen iodide concentration step, hydrogen iodide / iodine distillation step, hydrogen iodide decomposition step, hydrogen iodide / iodine recovery step, sulfuric acid purification step, sulfuric acid concentration A reaction control step for controlling a reaction in at least one step selected from a step, a sulfuric acid decomposition step and a sulfuric acid recovery step;
A thermochemical hydrogen production method characterized by comprising:

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