KR20130048585A - Hybrid hi decomposer for nuclear hydrogen production and the continuous sepatation process using the same - Google Patents

Abstract

PURPOSE: A hybrid-type hydrogen iodide decomposition device for atomic power hydrogen production and a method thereof are provided to increase hydrogen production efficiency in whole process by increasing degradability of unreacted hydrogen iodide. CONSTITUTION: A hybrid-type hydrogen iodide decomposition device for atomic power hydrogen production comprises a Bunsen reactor (1); a flash vaporizer (1'); a primary catalytic cracker (2); n-number of temperature changeable multi-batch type secondary catalytic crackers (4,5); a hydrogen storage container (8); n orientation fluid path selection valve (3); and three-way fluid path selection valves (6,7). The Bunsen reactor produces hydrogen iodide and sulfuric acid. The flash vaporizer concentrates the produced hydrogen iodide mixture. The primary catalytic cracker decomposes the concentrated hydrogen iodide into hydrogen and iodide under the presence of catalyst. The secondary catalytic cracker absorbs, decomposes, and attaches and detaches the hydrogen iodide which may not be decomposed in the primary catalytic cracker under the presence of an absorber including the catalyst by temperature control.

Description

Hybrid HI decomposer for Nuclear Hydrogen Production and the continuous sepatation process using the same}

The present invention relates to a hybrid type hydrogen iodide cracking apparatus for nuclear hydrogen production and a continuous hydrogen decomposition method using the same.

As the problem of depletion of energy resources is gradually revealed around the world, interest in next generation energy is increasing. Among them, hydrogen energy is in the spotlight as secondary energy to be used for transportation fields and remote areas where it is difficult to supply electricity directly at the present time when the petroleum price is expected to continuously increase and the fossil resources are depleted. In particular, as the Kyoto Protocol came into force in February 2005 to prevent global warming, the reduction of carbon dioxide has emerged as an important topic, and interest in hydrogen energy as an alternative energy source is increasing.

In order to obtain hydrogen, hydrogen present in the form of a compound must be separated. The most common example is a method of separating water (H ₂ O) into hydrogen (H ₂ ) and oxygen (O). Currently, the most widely used methods include steam reforming, electrolysis, and thermochemical decomposition of methane contained in natural gas.

Steam reforming is produced by reacting methane in natural gas with a high temperature steam in a nickel catalyst to decompose hydrogen and carbon monoxide. Currently, we are researching for commercialization technology, which accounts for 48% of the 42 million tons produced annually in the world, or miniaturization and lightening, which are required for the use of fuel cell power generation.

Electrolysis is a method in which a current of more than 1.75 volts flows into water to produce oxygen at the anode and hydrogen at the cathode. Electrolysis is the simplest, most reliable and has the advantage of obtaining high purity hydrogen. On the other hand, the high temperature is required for decomposition and hydrogen and oxygen are generated at the same time, so it is difficult to be commercialized because it is not easy to separate.

Thermal chemical decomposition is a method of decomposing water into hydrogen and oxygen through several chemical processes at a high temperature of 800 ℃ using nuclear or solar heat as a heat source. In particular, hydrogen production from water using thermal energy of 950 ° C. or higher in a VHTR is considered to be one of the most effective large-capacity hydrogen production methods among thermal chemical decomposition methods for producing hydrogen using nuclear power as a heat source.

Representative processes for producing hydrogen using thermochemical decomposition include the Sulfur-Iodine Thermochemical Cycle Process (SI process), calcium bromide (CaBr ₂ ) and bromination using sulfuric acid and hydrogen iodide. Laboratory scale demonstrations such as the UT-3 cycle using iron (FeBr ₂ ) have been studied, but the SI process using liquid is evaluated as the most advanced step in the mass continuous process.

The basic concept of the SI process was first presented by General Atomic (GA) of the United States in the early 1980's, and it was largely the Bunsen reaction process (Scheme 1), sulfuric acid (H ₂ SO ₄ ) decomposition process (Scheme 2), and iodide. Consisting of the hydrogen (HI) decomposition process (Scheme 3) and the SI process represented by the chemical reaction formula consists of the final chemical reaction as shown below.

<Reaction Scheme 1>

2H ₂ O + I ₂ + SO ₂ = 2HI + H ₂ SO ₄ (bunsen reaction, about 100 ℃, exothermic reaction)

<Reaction Scheme 2>

2HI = H ₂ + I ₂ (200 ~ 500 ℃, endothermic reaction)

<Reaction Scheme 3>

H ₂ SO ₄ = H ₂ O + SO ₂ + 0.5 O ₂ (about 850 ℃, endothermic reaction)

Scheme 1, named Bunsen reaction, is an exothermic reaction, and hydrogen iodide in <Scheme 2> proceeds as a solid catalytic reaction in a gaseous state or a homogeneous catalysis in a liquid state.

The sulfuric acid decomposition reaction of <Scheme 3> is firstly decomposed into water and sulfur trioxide at 400 to 500 ° C., and the decomposed sulfur trioxide (SO ₃ ) is secondly decomposed into sulfur dioxide and oxygen by a solid catalytic reaction at about 800 ° C. or more.

The reaction is described in detail as follows.

<Scheme 1> is a process of producing sulfuric acid (H ₂ SO ₄ ) and hydrogen iodide (HI) by the reaction of water (H ₂ O), sulfur dioxide (SO ₂ ), iodine (I ₂ ). This process not only promotes forward progress of Reaction 1 by appropriately adding excessive amount of iodine, but also causes immiscibility so that the sulfuric acid phase and the hydrogen iodide phase can be separated from each other. This reaction is a little exothermic and the reaction temperature is about 100 ° C. The resulting sulfuric acid and hydrogen iodide are spontaneous liquid-liquid phase separation, and the relatively heavy hydrogen iodide phase is positioned at the bottom and the sulfuric acid phase is at the top, and each separated phase is moved to the next process to be used as a reactant in each process.

In the hydrogen iodide decomposition process of Scheme 2, the hydrogen iodide solution is heated to thermally decompose or catalytically dissolve hydrogen iodide molecules into hydrogen (H ₂ ) and iodide (I ₂ ), and the hydrogen produced through this is separated into a final product. Water and iodine recovered during the concentration and decomposition process are recycled to the Bunsen reaction process.

In the sulfuric acid decomposition process of <Scheme 3>, when sulfuric acid solution is heated to about 850 ° C, it is easily and quickly decomposed into water (H ₂ O) and sulfur trioxide (SO ₃ ), and the produced sulfur trioxide (SO ₃ ) is a high temperature thermal energy from the reactor. It is decomposed into oxygen (O ₂ ) and sulfur dioxide (SO ₂ ). In the cracked product, oxygen is separated into the final product, and the water and sulfur dioxide recovered during sulfuric acid concentration and decomposition are recycled to the Bunsen reaction process by lowering the temperature.

In order for the iodine-sulfur decomposition reaction to proceed smoothly, the entire process must be organically connected.However, the hydrogen iodide decomposition reaction of <Scheme 2> is a factor limiting the efficiency of the entire hydrogen production plant due to the low thermodynamic decomposition rate and reaction rate. It is working.

In order to overcome this problem, Korean Patent Publication No. 2007-0058243 discloses that the hydrogen iodide mixed solution obtained as a result of the Bunsen reaction is concentrated in an electrodialysis apparatus and a multistage distillation apparatus and decomposed in a multistage cracking reactor, and then the unreacted hydrogen iodide mixed gas is electrodialyzed. An apparatus for increasing the decomposition rate of hydrogen iodide by re-introducing into an oxidation reaction chamber of the apparatus is described.

The hydrogen iodide decomposing method according to the inventors concentrated / decomposed hydrogen iodide for nuclear hydrogen production is concentrated by distillation after moving the molar fraction of hydrogen iodide above the azeotropic point using an electrodialysis apparatus, so that energy can be optimized. In addition, there is an advantage that the efficiency of nuclear hydrogen production can be improved by using a membrane decomposition reaction device that selectively separates hydrogen during decomposition of hydrogen iodide.

On the other hand, when using an electrodialysis device, there are disadvantages in overcoming the thermodynamic yield for cost, development of a membrane having excellent selectivity for a particular ion, and an increase in cell resistance as the number of membranes increases. .

In addition, Japanese Patent Laid-Open No. 2005-289733 describes a device for overcoming a reaction equilibrium by increasing a hydrogen iodide decomposition rate by connecting a device containing a hydrogen iodide pyrolysis device and an iodine fixative. This is based on the principle that the iodine content of the iodine fixative, which is mainly composed of metals, depends on the temperature. The iodine generated at a lower temperature is trapped to lower the proportion of the product in the cracker so that further reaction can occur. After the reaction, the temperature is raised to remove the fixed iodine to restore the fixative.

If this method is used, it is possible to obtain a decomposition rate exceeding the thermodynamic yield even at a low temperature.However, unlike conventional catalytic crackers, the decomposition capacity is determined. There is a lack of persistence and stability.

The present inventors have completed the present invention by developing a device for increasing the decomposition rate of hydrogen iodide by connecting a multi-batch second catalytic cracker including a temperature conversion process in parallel.

SUMMARY OF THE INVENTION An object of the present invention is to provide a hybrid type hydrogen iodide cracking apparatus for nuclear hydrogen production.

Still another object of the present invention relates to a method of continuously decomposing hydrogen using a hybrid type hydrogen iodide decomposing device for nuclear hydrogen production.

The present invention for achieving the above object

A Bunsen reactor for producing hydrogen iodide and sulfuric acid;

A flash distillation unit for concentrating the hydrogen iodide mixture produced from the bunsen reactor;

A first catalytic cracker for decomposing concentrated hydrogen iodide into hydrogen and iodine in the presence of a catalyst;

N temperature-converted multi-batch second catalytic crackers for performing adsorption, decomposition, and desorption of hydrogen iodide not decomposed in the first catalytic cracker through temperature control in the presence of an adsorbent including a catalyst;

A hydrogen storage container for storing hydrogen generated from the first catalytic cracker and the temperature-converted multiple batch second catalytic cracker;

An n-way flow path selection valve provided on a flow path connecting the first catalytic cracker and the n multiple batch second catalytic crackers; And

It provides a hybrid-type hydrogen iodide decomposition apparatus for nuclear hydrogen production comprising a three-way flow path selection valve provided on the flow path connecting the multi-batch second catalytic cracker, the hydrogen storage vessel and the Bunsen reactor.

In addition, the present invention comprises the steps of preparing hydrogen iodide and sulfuric acid by reacting iodine, water and sulfur dioxide in a Bunsen reactor (step 1);

Concentrating the hydrogen iodide mixture produced in step 1 in a flash still (step 2);

Decomposing the hydrogen iodide produced in step 2 into hydrogen and iodine in the presence of a catalyst in a first catalytic cracker (step 3);

Obtaining additional hydrogen by performing adsorption, decomposition and desorption through temperature control in a temperature-converted multi-batch second catalytic cracker including an adsorbent including a catalyst for the unreacted hydrogen iodide in step 3 (step 4);

Continuous hydrogen decomposition method using a hybrid type hydrogen iodide cracker for nuclear hydrogen production, comprising: collecting the hydrogen gas produced in step 4, recovering the remaining iodine and reusing it in the Bunsen reaction (step 5); Provided are hydrogen decomposition methods.

According to the present invention, the decomposition rate of unreacted hydrogen iodide is decomposed by the decomposition of unreacted hydrogen iodide in a first catalytic cracker of hydrogen iodide through a temperature conversion multiple batch second catalyst cracker further provided after the first catalytic cracker. It is possible to increase the hydrogen production efficiency in the whole process.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a schematic diagram showing a hybrid type hydrogen iodide cracking apparatus having a temperature conversion type multi-batch second catalytic cracker according to an embodiment of the present invention.
Figure 2 is a schematic diagram showing a hydrogen iodide decomposition apparatus performed in Experimental Example 1, Experimental Example 2 of the present invention.
Figure 3 is a graph of the thermogravimetric analysis of the alumina-based nickel catalyst for hydrogen iodide.
Figure 4 is a graph of the thermogravimetric analysis of the alumina-based nickel catalyst for iodine.
FIG. 5 is a graph showing the cumulative amount of hydrogen gas produced using 1 mL of hydrogen iodide and 3 g of catalyst at 250 ° C.
6 shows adsorption and decomposition using 1 mL of hydrogen iodide and 3 g of alumina-based nickel catalyst at 250 ° C., and desorption for 1 hour at 400 ° C., followed by repeated seven times. It is a graph showing the cumulative production of.
7 is adsorbed and decomposed using 1 mL of hydrogen iodide and 3 g of alumina-based nickel catalyst at 250 ° C., and desorption reaction at 450 ° C. for 1 hour, followed by two iterations of hydrogen gas. It is a graph showing the cumulative production of.
8 is a photograph taken at 500 times and 200,000 times magnification using a scanning electron microscope with respect to the surface of the adsorbent in which the desorption reaction does not occur.
FIG. 9 is a photograph taken at a magnification of 500 times and 200,000 times using a scanning electron microscope with respect to the surface of the adsorbent having desorption at 550 ° C. FIG.
Description of the Related Art
1: Bunsen reactor
1 ': flash distiller
2: first catalytic cracker
3: n-way flow path control valve of unreacted hydrogen iodide
4, 5: Temperature-Converted Multi-Batch Second Catalytic Cracker
6, 7: 3-way flow selector control valve of generated hydrogen, desorbed hydrogen iodide and iodine
8: Hydrogen Storage Container
9: Highly concentrated hydrogen iodide transfer tube
10: unreacted hydrogen iodide outlet pipe
11, 12: unreacted hydrogen iodide inlet pipe
13, 14: generated hydrogen; Or desorbed hydrogen iodide and iodine outlet tubes
15, 18: hydrogen gas inlet pipe
16, 17, 19: hydrogen iodide and iodine gas recovery pipe

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings in order to facilitate a person skilled in the art to easily carry out the technical idea of the present invention. . In the drawings, the same reference numerals are used to designate the same or similar components throughout the drawings. In the following description of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear.

The present invention provides a hybrid type hydrogen iodide cracking device for nuclear hydrogen production. As shown in FIG. 1, the present invention is a schematic diagram showing a hybrid type hydrogen iodide decomposition apparatus in which a first catalytic cracker 2 and a temperature-converted multiple batch second catalytic cracker 4 and 5 are provided in series.

Hereinafter, the present invention will be described in detail with reference to FIG. 1.

Hybrid type hydrogen iodide decomposition device for nuclear hydrogen production according to the present invention

A Bunsen reactor (1) for producing hydrogen iodide and sulfuric acid;

A flash still (1 ') for concentrating the hydrogen iodide mixture produced from the bunsen reactor (1);

A first catalytic cracker (2) for decomposing the concentrated hydrogen iodide from the flash still (1 ') into hydrogen and iodine in the presence of a catalyst;

N temperature-converted multi-batch second catalytic crackers (4, 5) for performing adsorption, decomposition and desorption on the first catalyst cracker (2) through temperature control of hydrogen iodide not decomposed in the presence of an adsorbent including a catalyst;

A hydrogen storage container (8) for storing hydrogen generated from the first catalytic cracker (2) and the temperature-converted multiple batch second catalytic cracker (4, 5);

An n-directional flow path selection control valve (3) provided on a flow path connecting the first catalytic cracker (2) and the n multiple batch-type second catalytic crackers (4, 5); And

It comprises a three-way flow path selection control valve (6, 7) provided on the flow path connecting the multi-batch second catalytic cracker (4, 5), hydrogen storage container (8) and Bunsen reactor (1).

Hereinafter, the individual devices constituting the hybrid type hydrogen iodide cracking apparatus for producing nuclear hydrogen according to the present invention and the operation principle thereof will be described in detail.

First, in the hybrid type hydrogen iodide decomposition device for nuclear hydrogen production according to the present invention, the Bunsen reactor 1 generates hydrogen iodide and sulfuric acid from iodine, sulfur dioxide and water through the Bunsen reaction shown in <Reaction Scheme 1>. Device.

The Bunsen reactor (1) is provided with a flash distillator (1 ') for concentrating the hydrogen iodide produced through the Bunsen reaction in one or a separate type, the first catalytic cracker (2) and the second catalytic cracker ( Hydrogen iodide and iodine gas recovery pipes (16, 17, 19) generated in 4, 5) is composed of a connection.

<Reaction Scheme 1>

2H ₂ O + I ₂ + SO ₂ = 2HI + H ₂ SO ₄ (bunsen reaction, about 100 ℃, exothermic reaction)

Next, in the hybrid type hydrogen iodide decomposing apparatus for nuclear hydrogen production according to the present invention, the Bunsen reactor 1 is assisted to produce high purity hydrogen iodide provided integrally or separately through the flash distillation unit 1 '. do.

The flash still 1 'serves to concentrate the hydrogen iodide mixture obtained through the bunsen reactor 1. Specifically, in order to increase the hydrogen production efficiency, the hydrogen iodide mixture is increased above the azeotropic concentration and concentrated using a pressure difference.

Since a high concentration of hydrogen iodide gas can be obtained through the flash distiller 1 ′, economic efficiency can be improved by reducing energy consumption of the process and simplifying the process, and there is an effect of increasing hydrogen production efficiency.

Next, in the hybrid type hydrogen iodide cracking apparatus for nuclear hydrogen production according to the present invention, the first catalytic cracker 2 is connected to the end of the flash distiller 1 'via a hydrogen iodide moving tube 9. The first catalytic cracker 2 is a straight reactor that decomposes hydrogen iodide into hydrogen and iodine at a high temperature of 650 ° C. or higher in the presence of an alumina nickel catalyst. At this time, the equilibrium decomposition rate of hydrogen iodide in the first catalytic cracker 2 is about 30% and the unreacted hydrogen iodide reaches 70% or more. The hydrogen gas generated through the first catalytic cracker 2 is supplied to the temperature conversion type multi-batch second catalytic cracker 4 together with the unreacted hydrogen iodide through the flow path selector valve 3. However, since hydrogen is not adsorbed to the adsorbent including the catalyst, the hydrogen gas passes through the second catalyst cracker 4 as it is, and then through the hydrogen gas outlet pipes 13 and 14, the three-way flow path selector valves 6 and 7. Is stored in the hydrogen storage container (8).

Next, in the hybrid type hydrogen iodide cracker for nuclear hydrogen production according to the present invention, the temperature conversion type multi-batch second catalytic cracker (4) is the first catalytic cracker (2) to increase the decomposition rate of unreacted hydrogen iodide It is further provided at the end. The temperature-converted multi-batch second catalytic cracker 4 adjusts the temperature below the desorption temperature, thereby adsorbing unreacted hydrogen iodide that is not decomposed from the first catalytic cracker 2 to the adsorbent including the catalyst, and undergoes a decomposition reaction. To produce hydrogen. Since the generated hydrogen may not be adsorbed by the adsorbent and may be immediately exported to the hydrogen storage device 8, the decomposition rate may be obtained by causing chemical non-equilibrium to exceed the equilibrium decomposition rate.

A pellet-type alumina nickel catalyst may be used as an adsorbent including a catalyst in the hydrogen iodide decomposition process performed in the second catalytic cracker 4, but is not limited thereto. Decomposition of hydrogen iodide that failed to react in the first catalytic cracker (2) by desorption by heating the iodine adsorbed on the adsorbent including the catalyst and the iodine adsorbed on the adsorbent above the desorption temperature, thereby desorption The reaction can proceed and additional hydrogen can be produced through adsorption and decomposition reactions. In the second catalytic cracker 4, the adsorbent including the hydrogen iodide and the iodine desorbed catalyst can be reused until the end of the life as the adsorbent.

After the adsorption of hydrogen iodide and iodine to the adsorption capacity, the second catalytic cracker 4 is heated to a high temperature in order to perform the desorption reaction in the temperature-converted multi-batch second catalytic cracker 4. The adsorbent having completed the desorption reaction can be reused.

Next, in the hybrid type hydrogen iodide cracking apparatus for nuclear hydrogen production according to the present invention, the second catalytic cracker 4 is provided so that the second catalytic cracker 5 having the same structure is connected in parallel. In the case of using a single second catalytic cracker, it may be limited to additionally introduce hydrogen iodide and perform adsorption and decomposition reactions during a high temperature desorption reaction. Accordingly, at least n second catalytic crackers capable of temperature conversion may be connected in parallel so as to perform the adsorption and decomposition process of the low temperature process and the desorption process of the high temperature process without stopping the process with mutual time difference. N is 2 or more, and may be provided in an appropriate number in consideration of the amount of hydrogen iodide to be decomposed and the efficiency of the entire process.

Next, in the hybrid type hydrogen iodide cracker for producing nuclear hydrogen according to the present invention, an n-way flow path control valve (1) is disposed between the first catalytic cracker (2) and the temperature-converted multi-batch second catalytic cracker (4, 5). 3) is provided.

Hydrogen iodide flows into the second catalytic cracker (4, 5) in which the adsorption and decomposition process is in progress, rather than the second catalytic cracker (4, 5) in which the hydrogen iodide is desorbed. It can be adjusted. Here, the direction number of the flow path selection control valve 3 is correlated with the number of second catalytic crackers connected in parallel.

Next, in the hybrid type hydrogen iodide decomposing apparatus for nuclear hydrogen production according to the present invention, a flow path connecting the temperature conversion type multi-batch second catalytic cracker (4, 5), hydrogen storage container (8) and Bunsen reactor (1) Three-way flow path control valves 6 and 7 are provided on the phase.

The three-way flow path control valves 6 and 7 are directionally controlled so that hydrogen generated through the low temperature adsorption and decomposition reactions in the second catalytic cracker 4 and 5 can be moved to the hydrogen storage container 8. In addition, the three-way flow path control valves 6 and 7 may recover the hydrogen iodide and iodine generated through the low-temperature adsorption and decomposition reaction in the second catalytic cracker 4 and 5 to the Bunsen reactor 1 and reuse them. Direction is adjusted.

The temperature range of the low temperature decomposition reaction and the high temperature desorption reaction occurring in the temperature-converted multi-batch second catalyst reactor 4 and 5 is determined by thermogravimetric analysis of hydrogen iodide adsorbed according to the type of adsorbent used.

Further, according to the present invention,

Reacting iodine, water and sulfur dioxide in a Bunsen reactor to produce hydrogen iodide and sulfuric acid (step 1);

Concentrating the hydrogen iodide mixture produced in step 1 in a flash still (step 2);

Decomposing the hydrogen iodide produced in step 2 into hydrogen and iodine in the presence of a catalyst in a first catalytic cracker (step 3);

Obtaining additional hydrogen by performing adsorption, decomposition and desorption through temperature control in a temperature-converted multi-batch second catalytic cracker including an adsorbent including a catalyst for the unreacted hydrogen iodide in step 3 (step 4);

It provides a continuous hydrogen decomposition method using a hybrid-type hydrogen iodide cracker for nuclear hydrogen production, including the step of collecting the hydrogen gas generated in step 4, recovering the remaining iodine and reusing it in the Bunsen reaction (step 5). do.

Hereinafter, a continuous hydrogen decomposition method using a hybrid type hydrogen iodide decomposition apparatus for nuclear hydrogen production according to the present invention will be described in more detail.

First, step 1 is a step of performing a Bunsen reaction by supplying iodine, water and sulfur dioxide to the Bunsen reactor as shown in Scheme 1. Hydrogen iodide and sulfur dioxide produced from the Bunsen reaction of step 1 are present in the Bunsen reactor in a mixture state.

Next, step 2 is a step of increasing the hydrogen iodide mixture above the azeotropy concentration and concentrating through a pressure difference. By effectively separating the hydrogen iodide and sulfur dioxide present in the mixture state through the concentration of the flash distillation to obtain a high concentration of hydrogen iodide gas, it is possible to improve the economic efficiency by reducing the energy consumption of the process and simplify the process, hydrogen The production efficiency can be improved.

Next, step 3 is a step of decomposing hydrogen iodide into hydrogen and iodine in the presence of an alumina nickel catalyst at a high temperature of 650 ℃ or more. In the decomposition reaction of hydrogen iodide, the equilibrium decomposition rate of hydrogen iodide reaches about 30%, and the undecomposed hydrogen iodide reaches 70% or more. Hydrogen generated from the decomposition reaction of hydrogen iodide is trapped in the hydrogen storage device because it is not adsorbed to the adsorbent in the second catalytic cracker.

Next, in step 4, hydrogen iodide that is not decomposed from the first catalytic cracker is adjusted to a temperature at which the adsorbent including the catalyst is adsorbed to adsorb the hydrogen iodide that is not decomposed in step 3, and the decomposition reaction is further performed. Decomposing hydrogen and iodine The adsorption reaction proceeds by adsorbing hydrogen iodide corresponding to the maximum adsorption capacity to the adsorbent.

Next, step 5 is hydrogen iodide adsorbed on the adsorbent, and decomposed by heating the iodine adsorbed by the adsorbent to a temperature above the desorption temperature. The time point of performing the desorption reaction of step 5 is to desorb by heating to a high temperature when the hydrogen iodide corresponding to the maximum adsorption capacity is adsorbed and decomposed to the adsorbent. In addition, the step 4 and step 5 are the adsorption and decomposition process with a time difference; And the temperature can be adjusted to perform the desorption process.

Hydrogen generated in the desorption reaction of step 5 is collected in a hydrogen storage device, and iodine is sent to the Bunsen reactor for reuse.

Experimental Example 1 Determination of Adsorption and Decomposition Temperature of Hydrogen Iodide

In the hybrid type hydrogen iodide cracking apparatus for nuclear hydrogen production according to the present invention, the following experiment was performed using the apparatus as shown in FIG. 2 to determine the optimum adsorption temperature for the adsorbent of hydrogen iodide in the second catalytic cracker.

As a reactant, 1 mL of an azeotropic hydrogen iodide solution (manufacturer: Yakuri, concentration: 57 wt%) was injected into the upper portion of the quartz tube 1 inch in diameter using a syringe. Inside the quartz tube, 3 g of powdered alumina-based nickel catalyst (manufacturer: Sigma-Aldrich, surface area: 190 m ² / g) is used as an adsorbent containing a catalyst for the decomposition of hydrogen iodide. The fibers were sandwiched. The quartz tube was mounted inside the electric furnace, and the adsorption and decomposition reaction temperatures were set at 250 ° C. and 350 ° C., and the adsorption and decomposition reactions were performed at respective temperatures. As a carrier gas, a mixed gas of 80% argon and 20% hydrogen was used and placed at the tip of an electric heating furnace to transfer reactants and products. The flow rate of the carrier gas was 20 mL / min, and the adsorption and decomposition reaction proceeded while supplying the electric heating furnace. In addition, when unreacted hydrogen iodide is injected into the gas chromatograph, pipe corrosion may occur, so that sodium thiosulfate solution is placed at the tip of the gas chromatograph to block the supply of unreacted hydrogen iodide.

Hydrogen iodide was adsorbed directly to the catalyst while passing through the catalyst column, and then proceeded with the decomposition reaction. Hydrogen and iodine produced showed different adsorption and decomposition characteristics, and iodine tended to be easily adsorbed at low temperatures, while hydrogen was not absorbed on the surface.

The adsorption reaction proceeded until the surfaces of all the adsorbents were filled with hydrogen iodide and iodine.

Hydrogen gas generated during the adsorption and decomposition reaction of hydrogen iodide proceeds to a hydrogen storage vessel, resulting in an imbalance in the reaction, and can lead to an additional reaction according to the LeChatlier principle to cause a continuous hydrogen iodide decomposition reaction. there was.

The thermogravimetric analysis was carried out to find the optimum adsorption and decomposition temperature of hydrogen iodide by measuring the change in the amount of substance before and after the reaction of the alumina-based nickel catalyst reacted with the adsorption and decomposition reaction temperatures set at 250 ° C and 350 ° C respectively. Model name: TG 209 F3) was performed and the results are shown in FIGS. 3 and 4.

As shown in Figure 3, most of the hydrogen iodide transition occurred mainly at 250 ℃ to 350 ℃. This means that hydrogen iodide was adsorbed up to 250 ° C. in an alumina-based nickel catalyst and desorption started above that temperature.

The thermogravimetric analysis of iodine of FIG. 4 also showed a similar tendency to the graph of hydrogen iodide at 250 ° C. to 400 ° C., but there was a temporary increase in iodine in the graph because of the formation of NiI ₂ molecules. .

In addition, the hydrogen gas moved along the carrier gas was fed into a gas chromatograph (manufacturer: DS Science, model name: DS 6200) for analysis and could be used to calculate the conversion rate of hydrogen iodide. The rate of decomposition was calculated by the hydrogen production. When 1 mL of hydrogen iodide is completely decomposed into hydrogen and iodine, 92 mL of hydrogen gas is produced. The decomposition rate of hydrogen was calculated by the following <formula 1>.

<Calculation Formula 1>

The amount of hydrogen gas produced was calculated by calculation based on the flow rate of the carrier gas.

Based on the above reaction, the total decomposition rate at 250 ° C. was calculated by the above <Calculation Equation 1>. As a result, the decomposition rate was hardly achieved in the experiment at 350 ° C., as shown in FIG. 5. This is because hydrogen iodide and iodine were hardly adsorbed at 350 ° C.

Through these experimental results, it was found that the optimal adsorption and decomposition reaction of hydrogen iodide can be performed at 250 ℃.

Experimental Example 2 Determination of Desorption Temperature of Hydrogen Iodide

In the hybrid type hydrogen iodide cracking apparatus for nuclear hydrogen production according to the present invention, the following experiment was performed using the apparatus as shown in FIG. 2 to determine the optimum desorption temperature for the adsorbent of hydrogen iodide in the second catalytic cracker.

As a reactant, 1 mL of an azeotropic hydrogen iodide solution (manufacturer: Yakuri, concentration: 57 wt%) was injected into the upper portion of the quartz tube 1 inch in diameter using a syringe. Inside the quartz tube, 3 g of powdered alumina-based nickel catalyst (manufacturer: Sigma-Aldrich, surface area: 190 m ² / g) is used as an adsorbent containing a catalyst for the decomposition of hydrogen iodide. The fibers were sandwiched. The quartz tube was mounted inside the electric furnace, and the adsorption and decomposition reaction temperature was set at 250 ° C. according to the result of Experimental Example 1, and the desorption temperature was set at 350 ° C., 400 ° C., 450 ° C., 500 ° C. and 550 ° C. The amount of material analysis and the decomposition rate before and after the reaction of the adsorbent according to the desorption temperature were measured. As a carrier gas, a mixed gas of 80% argon and 20% hydrogen was used and placed at the tip of an electric heating furnace to transfer reactants and products. The flow rate of the carrier gas was 20 mL / min, and the desorption reaction was performed for 1 hour while feeding the electric furnace. In addition, when unreacted hydrogen iodide is injected into the gas chromatograph, pipe corrosion may occur, so that sodium thiosulfate solution is placed at the tip of the gas chromatograph to block the supply of unreacted hydrogen iodide.

The optimum desorption reaction was determined based on the decomposition rate of the alumina nickel catalyst before and after the desorption reaction and the scanning electron microscope (manufacturer: FEI company, model name: Magellan 400) according to the set desorption temperature.

As a result of observing the reaction, it was found that the desorption reaction was hardly performed at 350 ° C. This is because the temperature was not high enough to desorb hydrogen iodide and iodine from the adsorbent surface at 350 ° C.

In the desorption reaction at 400 ° C., as shown in FIG. 6, the total decomposition rate was measured at 40%. As a result, the degradation rate was not observed as a result of repeating the desorption reaction 7 times.

On the other hand, the desorption reaction at 450 ° C. was similar to the desorption reaction at 400 ° C., but the total decomposition rate was measured to be 40%. However, when the adsorbent was used once and twice, the degradation rate rapidly decreased as shown in FIG. 7. there was.

In addition, at 550 ° C., hydrogen and iodine were effectively desorbed, but it was confirmed that the adsorbent was damaged based on the color of the adsorbent surface and the scanning electron micrograph of FIG. 9. First, when comparing the color of the surface of the adsorbent, the color of the adsorbent adsorbed and decomposed at 250 ℃ was black, but after desorption at 550 ℃, the surface of the adsorbent was identified as gray.

In addition, when comparing the scanning electron micrographs shown in Figures 8 to 9, all pictures taken at 500 times magnification shows a similar aspect, but in the case of pictures taken at 200,000 times magnification, it can be seen that different shapes depending on the desorption temperature. there was. As shown in FIG. 8, the surface of the adsorbent in which the desorption reaction did not occur was observed to have a loose structure with small pores.

On the other hand, as can be seen in Figure 9, the catalyst surface subjected to the desorption reaction showed a dense structure covered with nanometer-sized pores. This structure caused physical degradation such as a reduction in surface area, reducing the chance of hydrogen iodide and iodine contacting the adsorbent.

Through these experimental results, the optimum temperature for the desorption reaction could be determined as 400 ℃.

Claims (15)

A Bunsen reactor for producing hydrogen iodide and sulfuric acid;
A flash distillation unit for concentrating the hydrogen iodide mixture produced from the bunsen reactor;
A first catalytic cracker for decomposing concentrated hydrogen iodide into hydrogen and iodine in the presence of a catalyst;
N temperature-converted multi-batch second catalytic crackers for performing adsorption, decomposition, and desorption of hydrogen iodide not decomposed in the first catalytic cracker through temperature control in the presence of an adsorbent including a catalyst;
A hydrogen storage container for storing hydrogen generated from the first catalytic cracker and the temperature-converted multiple batch second catalytic cracker;
An n-way flow path selection valve provided on a flow path connecting the first catalytic cracker and the n multiple batch second catalytic crackers; And
And a three-way flow path selection valve provided on a flow path connecting the multi-batch second catalytic cracker, a hydrogen storage container, and a Bunsen reactor to produce a hybrid type hydrogen iodide decomposition device for nuclear hydrogen production.
According to claim 1, wherein the Bunsen reactor is hybrid type hydrogen iodide decomposition apparatus for nuclear hydrogen production, characterized in that for generating hydrogen iodide and sulfuric acid from iodine, sulfur dioxide and water.
2. The hybrid type hydrogen iodide cracker for nuclear hydrogen production according to claim 1, wherein the flash distillator increases the hydrogen iodide mixture to an azeotropic concentration or higher and concentrates the pressure difference to increase hydrogen production efficiency.
The hybrid type hydrogen iodide decomposition apparatus for nuclear hydrogen production according to claim 1, wherein the first catalytic cracker decomposes hydrogen iodide into hydrogen and iodine in the presence of an alumina nickel catalyst.
The method of claim 1, wherein the temperature conversion multi-batch second catalytic cracker is adjusted to a temperature below the desorption temperature, thereby adsorbing hydrogen iodide not decomposed from the first catalytic cracker to the adsorbent including the catalyst, hydrogen through a decomposition reaction Hybrid type hydrogen iodide cracking device for nuclear hydrogen production, characterized in that to produce a.
2. The nuclear hydrogen reactor according to claim 1, wherein the temperature-converted multi-batch second catalytic cracker is decomposed by hydrogen iodide adsorbed on the adsorbent and decomposition reaction by heating the iodine adsorbed on the adsorbent above the desorption temperature. Hybrid type hydrogen iodide digester for production.
The hybrid type hydrogen iodide cracker for nuclear hydrogen production according to claim 5, wherein the adsorbent comprising hydrogen iodide and a catalyst desorbed iodine is reused.
The method of claim 1, wherein the high temperature heating of the second catalytic cracker for the desorption reaction in the temperature conversion multi-batch second catalytic cracker is carried out at the time when the adsorbent capacity of hydrogen iodide is adsorbed to regenerate the adsorbent. Hybrid type hydrogen iodide cracker for nuclear hydrogen production.
[Claim 2] The hybrid type hydrogen iodide cracker for nuclear hydrogen production according to claim 1, wherein the temperature-converted multi-batch second catalytic cracker has n catalytic crackers connected in parallel.
10. The hybrid type hydrogen iodide cracker for nuclear hydrogen production according to claim 9, wherein the temperature of the n catalytic crackers is controlled to perform adsorption, decomposition and desorption processes with time difference.
According to claim 1, wherein the n-way flow path selection valve provided between the first catalytic cracker and the n multi-batch second catalytic cracker is the adsorption and decomposition process is not a second catalyst cracker in the desorption process of hydrogen iodide supplied Hybrid type hydrogen iodide cracking device for nuclear hydrogen production, characterized in that it is adjusted to be introduced into the ongoing second catalytic cracker.
According to claim 1, wherein the three-way flow path selection valve provided on the flow path connecting the temperature conversion multi-batch second catalytic cracker, hydrogen storage vessel and Bunsen reactor is generated by the low temperature adsorption and decomposition reaction in the second catalytic cracker Hybrid type hydrogen iodide decomposing device for nuclear hydrogen production, characterized in that the hydrogen is controlled to be moved to the hydrogen storage vessel.
According to claim 1, wherein the three-way flow path selection valve provided on the flow path connecting the temperature conversion multi-batch second catalytic reactor, hydrogen storage vessel and Bunsen reactor is generated by the low temperature adsorption and decomposition reaction in the second catalytic cracker A hybrid type hydrogen iodide cracker for nuclear hydrogen production, characterized in that the hydrogen iodide and iodine are introduced into the Bunsen reactor to be reused.
The temperature range of the low temperature decomposition reaction and the high temperature desorption reaction in the temperature-converted multi-batch second catalytic reactor is determined by thermogravimetric analysis of hydrogen iodide adsorbed according to the type of adsorbent used. Hybrid type hydrogen iodide cracker for nuclear hydrogen production.
Reacting iodine, water and sulfur dioxide in a Bunsen reactor to produce hydrogen iodide and sulfuric acid (step 1);
Concentrating the hydrogen iodide mixture produced in step 1 in a flash still (step 2);
Decomposing the hydrogen iodide produced in step 2 into hydrogen and iodine in the presence of a catalyst in a first catalytic cracker (step 3);
Obtaining additional hydrogen by performing adsorption, decomposition and desorption through temperature control in a temperature-converted multi-batch second catalytic cracker including an adsorbent including a catalyst for the unreacted hydrogen iodide in step 3 (step 4);
Collecting the hydrogen gas produced in step 4, recovering the remaining iodine and reusing in the Bunsen reaction (step 5); continuous hydrogen decomposition method using a hybrid-type hydrogen iodide cracker for nuclear hydrogen production comprising

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