Kinetics and modeling of hydrogen iodide decomposition for a bench-scale sulfur–iodine cycle

Nguyen, Trung Dac; Gho, Yun-Ki; Cho, Won Chul; Kang, Kiyoon; Jeong, Soon‐Yong; Kim, Chang Hee; Park, Chu-Sik; Bae, Ki Kwang

doi:10.1016/j.apenergy.2013.09.041

Cited by 29 publications

(19 citation statements)

References 20 publications

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“…The influence of operating temperature on the electrolytic performance was analyzed in two opposite aspects. First, increase in temperature enhances the activity of species in the solution and increases the reaction kinetic rate because of the endothermic characteristic of HI decomposition . On contrary, the rising temperature reduces the local current density according to Equation .…”

Section: Resultsmentioning

confidence: 99%

Modeling and experimental assessment of the novel HI‐I ₂ ‐H ₂ O electrolysis for hydrogen generation in the sulfur‐iodine cycle

et al. 2020

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Summary To improve the sulfur‐iodine (SI or IS) cycle for renewable hydrogen production, direct electrolysis of HIx solution (HI‐I2‐H2O) from Bunsen reaction has been recently proposed. This work concerns the detailed microscopic physical performance and electrolytic processes of HIx electrolysis through theoretical simulation and experimental exploration. A two‐dimensional mathematical model of the electrolytic cell for HIx electrolysis was developed, and was verified by the relevance between the simulated and experimental hydrogen production. The concentration, electric and flow field distributions were characterized. The decrease of anodic HI and increase of cathodic H2 were found along the flow direction. The local potential distribution declined from anode to cathode region. Higher pressure drop from the inlet to outlet of channel as well as the pumping power were required for anolyte than catholyte. More detailed electrolytic processes along the flow channel at different operating conditions were analyzed. Increasing temperature from 303 K to 343 K improved the H2 production rate. A low anode flow rate of 0.2 m/s was favorable for achieving high conversion rate of reactants and low consumed pumping power. The developed models and the clarified characteristics of HIx electrolysis will be further applied to the improved SI cycle.

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Section: Resultsmentioning

confidence: 99%

Modeling and experimental assessment of the novel HI‐I ₂ ‐H ₂ O electrolysis for hydrogen generation in the sulfur‐iodine cycle

et al. 2020

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“…Secondly, by changing t and flow rate of helium gas respectively, two other modified reac length will be designed. uniformly filled in the tube, and the particle diameter is dp The helium tion mixture temperature, total pressure, and molar flow rate ca e ( ), ( ), ( ) H T z T z P z and k ( ) F z , respectively, where z represents the a fixed bed reactor with given parameters, the axial back mixing in th nored, and the plug flow model is applicable [15]. Figure 2 shows the of the tubular plug flow reactor model.…”

Section: The System Description 21 Reactor Modelmentioning

confidence: 99%

“…where q represents heat flux passing the tube wall, q = U(T He − T) when the process obeys Newton's law of cooling, U, which is the overall heat transfer coefficient, can be approximated as a constant value 170 W/(m 2 • K) [15]. ρ c and A c are the catalyst particle density and crosssectional area of the reaction tube respectively, ε is the void fraction of catalyst bed, and r HI is the HI decomposition reaction rate, which is strongly dependent on the temperature.…”

Section: Conservation Equationsmentioning

confidence: 99%

“…where the values of the coefficients A k , B k , C k , D k and E k in the formula are listed in Table 2. The heat released by the high-temperature helium is used to heat the reactor, so the axial temperature distribution of helium gas along the tube can be expressed as [15]: It means that the helium is heated in a counter-current way, so the temperature of helium gas gradually increases along the positive axis. C p,He is the molar heat capacity of helium, and the value is 20.786 J/(mol • K).…”

Section: Conservation Equationsmentioning

confidence: 99%

“…There are three main chemical reactions in the thermochemical S-I cycle, wh the Bunsen reaction, sulfuric acid decomposition and HI decomposition reactions 1 shows the schematic diagram of the S-I cycle. For the HI decomposition proces prehensive researches have been implemented including catalyst performance eva [10,11], reaction kinetics analysis [12][13][14][15] and reactor numerical simulation [16-1 conversion rate of HI decomposition reaction is low, which restricts the hydroge and thermal efficiency of the S-I cycle system, and the choice of decomposition te ture must take into account the heat resistance of the material and the thermal ef of the device. The HI decomposition process is considered to be one of the most steps in hydrogen production process using S-I cycle.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Minimization of Entropy Generation Rate in Hydrogen Iodide Decomposition Reactor Heated by High-Temperature Helium

Kong

Chen

Xia

et al. 2021

Entropy

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The thermochemical sulfur-iodine cycle is a potential method for hydrogen production, and the hydrogen iodide (HI) decomposition is the key step to determine the efficiency of hydrogen production in the cycle. To further reduce the irreversibility of various transmission processes in the HI decomposition reaction, a one-dimensional plug flow model of HI decomposition tubular reactor is established, and performance optimization with entropy generate rate minimization (EGRM) in the decomposition reaction system as an optimization goal based on finite-time thermodynamics is carried out. The reference reactor is heated counter-currently by high-temperature helium gas, the optimal reactor and the modified reactor are designed based on the reference reactor design parameters. With the EGRM as the optimization goal, the optimal control method is used to solve the optimal configuration of the reactor under the condition that both the reactant inlet state and hydrogen production rate are fixed, and the optimal value of total EGR in the reactor is reduced by 13.3% compared with the reference value. The reference reactor is improved on the basis of the total EGR in the optimal reactor, two modified reactors with increased length are designed under the condition of changing the helium inlet state. The total EGR of the two modified reactors are the same as that of the optimal reactor, which are realized by decreasing the helium inlet temperature and helium inlet flow rate, respectively. The results show that the EGR of heat transfer accounts for a large proportion, and the decrease of total EGR is mainly caused by reducing heat transfer irreversibility. The local total EGR of the optimal reactor distribution is more uniform, which approximately confirms the principle of equipartition of entropy production. The EGR distributions of the modified reactors are similar to that of the reference reactor, but the reactor length increases significantly, bringing a relatively large pressure drop. The research results have certain guiding significance to the optimum design of HI decomposition reactors.

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Clean hydrogen generation and storage strategies via CO ₂ utilization into chemicals and fuels: A review

et al. 2019

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Summary Hydrogen becomes one of the most clean energy sources. The major issues on hydrogen are lack of practical clean and high‐temperature processes and possible practical storage of clean hydrogen. An energy intensive of clean hydrogen storage via chemical and liquid fuel production route is the current demand. This article reviewed the most recent research for hydrogen (H2) production by using several methods, such as thermochemical process, thermal decomposition, biological approaches, electrolysis, and photocatalytic method. H2 storage types, including physical and chemical approaches, were also reviewed. The produced H2 was stored as valuable chemicals and fuels via CO2 hydrogenation reaction. Reactor designs are the illustrated number of design ranging from the fixed bed to the continuous stirred tank reactor. Catalyst type, catalytic system, and the related mechanism of CO2 hydrogenation reaction to form alcohol, alkanes, and carboxylic acid were also discussed in detail.

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Kinetics and modeling of hydrogen iodide decomposition for a bench-scale sulfur–iodine cycle

Cited by 29 publications

References 20 publications

Modeling and experimental assessment of the novel HI‐I ₂ ‐H ₂ O electrolysis for hydrogen generation in the sulfur‐iodine cycle

Modeling and experimental assessment of the novel HI‐I ₂ ‐H ₂ O electrolysis for hydrogen generation in the sulfur‐iodine cycle

Minimization of Entropy Generation Rate in Hydrogen Iodide Decomposition Reactor Heated by High-Temperature Helium

Clean hydrogen generation and storage strategies via CO ₂ utilization into chemicals and fuels: A review

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Kinetics and modeling of hydrogen iodide decomposition for a bench-scale sulfur–iodine cycle

Cited by 29 publications

References 20 publications

Modeling and experimental assessment of the novel HI‐I 2 ‐H 2 O electrolysis for hydrogen generation in the sulfur‐iodine cycle

Modeling and experimental assessment of the novel HI‐I 2 ‐H 2 O electrolysis for hydrogen generation in the sulfur‐iodine cycle

Minimization of Entropy Generation Rate in Hydrogen Iodide Decomposition Reactor Heated by High-Temperature Helium

Clean hydrogen generation and storage strategies via CO 2 utilization into chemicals and fuels: A review

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Modeling and experimental assessment of the novel HI‐I ₂ ‐H ₂ O electrolysis for hydrogen generation in the sulfur‐iodine cycle

Modeling and experimental assessment of the novel HI‐I ₂ ‐H ₂ O electrolysis for hydrogen generation in the sulfur‐iodine cycle

Clean hydrogen generation and storage strategies via CO ₂ utilization into chemicals and fuels: A review