• Title/Summary/Keyword: IS (iodine-Sulfur) process

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Effect of Iodine Input in the Liquid-Liquid Separation Properties on Bunsen Reaction Process (분젠반응공정에서 요오드 투입에 따른 2액상 분리 특성)

  • Jeong, Heondo;Kim, In-Hwan;Kim, Tae-Hwan;Choo, Ko-Yeon;Bae, Gi-Gwang
    • Korean Chemical Engineering Research
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    • v.46 no.3
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    • pp.633-638
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    • 2008
  • The bunsen reaction, part of IS(Iodine-sulfur) cycle that one of the hydrogen production by the thermochemical water splitting, was investigated. It was observed that $H_2SO_4$ was uniformly generated and generation of $H_2SO_4$ was independent of iodine input. However, generation of HI was decreased with increasing iodine input. It was thought that HI and unreacted iodine were formed complex compound such as $HI_3$ $HI_5$ or $HI_7$. The complex compound accelerated liquid-liquid separation properties in the product. It was also revealed that reaction kinetics was increased with increasing iodine input. Liquid-liquid separation properties were improved with increasing iodine input and reaction temperature. Moreover, no side reaction was occurred at all reaction conditions.

NUMERICAL ANALYSIS OF A SO3 PACKED COLUMN DECOMPOSITION REACTOR WITH ALLOY RA 330 STRUCTURAL MATERIAL FOR NUCLEAR HYDROGEN PRODUCTION USING THE SULFUR- IODINE PROCESS

  • Choi, Jae-Hyuk;Tak, Nam-Il;Shin, Young-Joon;Kim, Chan-Soo;Lee, Ki-Young
    • Nuclear Engineering and Technology
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    • v.41 no.10
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    • pp.1275-1284
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    • 2009
  • A directly heated $SO_3$ decomposer for the sulfur-iodine and hybrid-sulfur processes has been introduced and analyzed using the computational fluid dynamics (CFD) code CFX 11. The use of a directly heated decomposition reactor in conjunction with a very high temperature reactor (VHTR) allows for higher decomposition reactor operating temperatures. However, the high temperatures and strongly corrosive operating conditions associated with $SO_3$ decomposition present challenges for the structural materials of decomposition reactors. In order to resolve these problems, we have designed a directly heated $SO_3$ decomposer using RA330 alloy as a structural material and have performed a CFD analysis of the design based on the finite rate chemistry model. The CFD results show the maximum temperature of the structural material could be maintained sufficiently below 1073 K, which is considered the target temperature for RA 330. The CFD simulations also indicated good performance in terms of $SO_3$ decomposition for the design parameters of the present study.

Numerical Study on Heat Transfer Characteristics in a directly Heated $SO_3$ Decomposer for the Sulfur-Iodine process (황-요오드 공정용 직접접촉 삼산화황 분해반응기내 열전달 특성에 관한 수치적 연구)

  • Choi, Jae-Hyuk;Shin, Young-Joon;Tak, Nam-Il;Lee, Ki-Young;Chang, Jong-Wha;Chung, Suk-Ho
    • Proceedings of the KSME Conference
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    • 2007.05b
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    • pp.2244-2249
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    • 2007
  • A directly heated $SO_3$ decomposer for the sulfur-iodine and hybrid-sulfur processes has been introduced and analyzed by using a computational fluid dynamics code(CFD) with the CFX 5.7.1. The use of a directly heated decomposition reactor in conjunction with a VHTR allows higher decomposition reactor operating temperature. However, the thermochemical and hybrid hydrogen production processes accompanied with the high temperature and strongly corrosive operating conditions basically have material problems. In order to resolve these problems, we carried out the development of a structural material and equipment design technologies. The results show that the maximum temperature of the structural material (RA330) could be maintained at 800$^{\circ}C$ or less. Also, it can be seen that the mean temperature of the reaction region packed with catalysts in the $SO_3$ decomposition reactor could satisfy the temperature condition of around 850 $^{\circ}C$ which is the target temperature in this study.

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Design and Optimization of Pilot-Scale Bunsen Process in Sulfur-Iodine (SI) Cycle for Hydrogen Production (수소 생산을 위한 Sulfur-Iodine Cycle 분젠반응의 Pilot-Scale 공정 모델 개발 및 공정 최적화)

  • Park, Junkyu;Nam, KiJeon;Heo, SungKu;Lee, Jonggyu;Lee, In-Beum;Yoo, ChangKyoo
    • Korean Chemical Engineering Research
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    • v.58 no.2
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    • pp.235-247
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    • 2020
  • Simulation study and validation on 50 L/hr pilot-scale Bunsen process was carried out in order to investigate thermodynamics parameters, suitable reactor type, separator configuration, and the optimal conditions of reactors and separation. Sulfur-Iodine is thermochemical process using iodine and sulfur compounds for producing hydrogen from decomposition of water as net reaction. Understanding in phase separation and reaction of Bunsen Process is crucial since Bunsen Process acts as an intermediate process among three reactions. Electrolyte Non-Random Two-Liquid model is implemented in simulation as thermodynamic model. The simulation results are validated with the thermodynamic parameters and the 50 L/hr pilot-scale experimental data. The SO2 conversions of PFR and CSTR were compared as varying the temperature and reactor volume in order to investigate suitable type of reactor. Impurities in H2SO4 phase and HIX phase were investigated for 3-phase separator (vapor-liquid-liquid) and two 2-phase separators (vapor-liquid & liquid-liquid) in order to select separation configuration with better performance. The process optimization on reactor and phase separator is carried out to find the operating conditions and feed conditions that can reach the maximum SO2 conversion and the minimum H2SO4 impurities in HIX phase. For reactor optimization, the maximum 98% SO2 conversion was obtained with fixed iodine and water inlet flow rate when the diameter and length of PFR reactor are 0.20 m and 7.6m. Inlet water and iodine flow rate is reduced by 17% and 22% to reach the maximum 10% SO2 conversion with fixed temperature and PFR size (diameter: 3/8", length:3 m). When temperature (121℃) and PFR size (diameter: 0.2, length:7.6 m) are applied to the feed composition optimization, inlet water and iodine flow rate is reduced by 17% and 22% to reach the maximum 10% SO2 conversion.

Current Status of Nuclear Hydrogen Development (원자력을 이용한 수소생산기술 개발 동향)

  • Chang Jong-Hwa
    • Journal of Energy Engineering
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    • v.15 no.2 s.46
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    • pp.127-137
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    • 2006
  • To resolve the environmental and economics problems of fossil fuel energy, a hydrogen economy is promoted in many developed countries. Massive production of hydrogen using a nuclear power is a practical way to feed fuel required for the hydrogen economy. The author introduces a very high temperature reactor and its development status. He also reviews recent achievements and directions of research in hydrogen production process, such as sulfur-iodine thermochemical cycle, sulfur hybrid cycle, and high temperature electrolysis.

A Study on Initiating Events Identification of the IS Process

  • Cho, Nam-Chul;Jae, Moo-Sung;Eon, Yang-Joon
    • International Journal of Safety
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    • v.5 no.1
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    • pp.29-32
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    • 2006
  • There has been an increasing need for substitute energy development due to the dry up of the fossil fuel and environmental problems. Among the substitute energy under consideration, producing hydrogen from water without the accompanying release of carbon has become a promising technology. Also, Iodine-Sulfur (IS) thermochemical water decomposition is one of the promising processes that can produce hydrogen efficiently using the high temperature gas-cooled reactor (HTGR) as an energy source capable of supplying heat at over 1000. In this study, to effect an initiating events identification of the IS process, Master Logic Diagram (MLD) was used and 9 initiating events that cause a leakage of the chemical material were identified.

High Temperature Phase Separation of $H_2SO_4-HI-H_2O-I_2$ System In Iodine-Sulfur Hydrogen Production Process (Iodine-Sulfur 수소 제조 공정에서 $H_2SO_4-HI-H_2O-I_2$ 계의 고온 상 분리)

  • Lee, Dong-Hee;Lee, Kwang-Jin;Kang, Young-Han;Kim, Young-Ho;Park, Chu-Sik;Hwang, Gab-Jin;Bae, Ki-Kwang
    • Journal of Hydrogen and New Energy
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    • v.17 no.4
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    • pp.395-402
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    • 2006
  • Iodine-sulfur(IS) hydrogenation production process consists of three sections, which are so called a Bunsen reaction section, a HI decomposition section and a $H_2SO_4$ decomposition section as a closed cycle. For highly efficient operation of a Bunsen reaction section, we investigated the phase separation characteristics of $H_2SO_4-HI-H_2O-I_2$ system into two liquid phases($H_2SO_4$-rich phase and $HI_x$-rich phase) in the high temperature ranges, mainly from 353 to 393 K, and in the $H_2SO_4/HI/H_2O/I_2$ molar ratio of $1/2/14{\sim}30/0.3{\sim}13.50$. The desired results for the minimization of impurities in each phase were obtained in conditions with the higher temperature and the higher $I_2$ molar composition. On the basis of the distribution of $H_2O$ to each phase, it is appeared that the affinity between $HI_x$ and $H_2O$ was more superior to that between $H_2SO_4$ and $H_2O$.

Crystal Sinking Modeling for Designing Iodine Crystallizer in Thermochemical Sulfur-Iodine Hydrogen Production Process (열화학 황-요오드 수소 생산 공정의 요오드 결정화기 설계를 위한 결정 침강 모델링)

  • Park, Byung Heung;Jeong, Seong-Uk;Kang, Jeong Won
    • Korean Chemical Engineering Research
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    • v.52 no.6
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    • pp.768-774
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    • 2014
  • SI process is a thermochemical process producing hydrogen by decomposing water while recycling sulfur and iodine. Various technologies have been developed to improve the efficiency on Section III of SI process, where iodine is separated and recycled. EED(electro-electrodialysis) could increase the efficiency of Section III without additional chemical compounds but a substantial amount of $I_2$ from a process stream is loaded on EED. In order to reduce the load, a crystallization technology prior to EED is considered as an $I_2$ removal process. In this work, $I_2$ particle sinking behavior was modeled to secure basic data for designing an $I_2$ crystallizer applied to $I_2$-saturated $HI_x$ solutions. The composition of $HI_x$ solution was determined by thermodynamic UVa model and correlation equations and pure properties were used to evaluate the solution properties. A multiphysics computational tool was utilized to calculate particle sinking velocity changes with respect to $I_2$ particle radius and temperature. The terminal velocity of an $I_2$ particle was estimated around 0.5 m/s under considered radius (1.0 to 2.5 mm) and temperature (10 to $50^{\circ}C$) ranges and it was analyzed that the velocity is more dependent on the solution density than the solution viscosity.

Safety Assessments for the IS(Iodine Sulfur) Process in a Hydrogen Production Facility (수소생산시설에서의 요오드-황 공정에 대한 안전성 평가연구)

  • Lee, Hyon-Woo;Jae, Moo-Sung;Cho, Nam-Chul;Yang, Jon-Eon;Lee, Won-Jae
    • Journal of the Korean Society of Safety
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    • v.24 no.3
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    • pp.54-58
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    • 2009
  • A substitute energy development has been required due to the exhaust of the fossil fuel and an environmental problem. Consequently, possible technologies producing hydrogen from water that does not release carbon is a very promising technology. Also, Iodine-Sulfur(IS) thermochemical water decomposition is one of the promising processes that are used to produce hydrogen efficiently using the high temperature gas-cooled reactor(HTGR) as an energy source that is possible to supply heat over 900$^{\circ}C$. In this study, to make a initiating events identification for the IS process, Master Logic Diagram(MLD) is used and 9 initiating events that cause a leakage of the chemical material are identified. Also, 6 events are identified among 9 initiating events above and are quantified using event tree.

A DYNAMIC SIMULATION OF THE SULFURIC ACID DECOMPOSITION PROCESS IN A SULFUR-IODINE NUCLEAR HYDROGEN PRODUCTION PLANT

  • Shin, Young-Joon;Chang, Ji-Woon;Kim, Ji-Hwan;Park, Byung-Heung;Lee, Ki-Young;Lee, Won-Jae;Chang, Jong-Hwa
    • Nuclear Engineering and Technology
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    • v.41 no.6
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    • pp.831-840
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    • 2009
  • In order to evaluate the start-up behavior and to identify, through abnormal operation occurrences, the transient behaviors of the Sulfur Iodine(SI) process, which is a nuclear hydrogen process that is coupled to a Very High Temperature Gas Cooled Reactor (VHTR) through an Intermediate Heat Exchanger (IHX), a dynamic simulation of the process is necessary. Perturbation of the flow rate or temperature in the inlet streams may result in various transient states. An understanding of the dynamic behavior due to these factors is able to support the conceptual design of the secondary helium loop system associated with a hydrogen production plant. Based on the mass and energy balance sheets of an electrodialysis-embedded SI process equivalent to a 200 $MW_{th}$ VHTR and a considerable thermal pathway between the SI process and the VHTR system, a dynamic simulation of the SI process was carried out for a sulfuric acid decomposition process (Second Section) that is composed of a sulfuric acid vaporizer, a sulfuric acid decomposer, and a sulfur trioxide decomposer. The dynamic behaviors of these integrated reactors according to several anticipated scenarios are evaluated and the dominant and mild factors are observed. As for the results of the simulation, all the reactors in the sulfuric acid decomposition process approach a steady state at the same time. Temperature control of the inlet helium is strictly required rather than the flow rate control of the inlet helium to keep the steady state condition in the Second Section. On the other hand, it was revealed that the changes of the inlet helium operation conditions make a great impact on the performances of $SO_3$ and $H_2SO_4$ decomposers, but no effect on the performance of the $H_2SO_4$ vaporizer.