• Title/Summary/Keyword: Thermochemical conversion process

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Biomass to Energy: Renewable Fuel Production Processes for Clean Combustion (바이오매스 에너지화: 청정 연소를 위한 신재생 연료 생산 공정)

  • Jeong, Jaeyong;Kim, Youngdoo;Yang, Won;Lee, Uendo;Jeong, Suhwa;Bang, Byungryul;Moon, Jihong;Hwang, Jeongho;Chang, Wonsuk
    • 한국연소학회:학술대회논문집
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    • 2015.12a
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    • pp.285-285
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    • 2015
  • Utilization of biomass as a substitute fuel for conventional energy systems have been grown larger everyday in the world. In particular, co-firing of biomass in a large coal power plant are common in Korea after the introduction of RPS since 2012, and the application of biomass-derived fuel is now spreading to district heating and power, industrial energy supply, and transportation sectors. For biomass to energy, appropriate conversion process is needed to satisfy the fuel requirements of a specific energy system. In this study, various kinds of thermochemical conversion technologies will be presented for renewable fuel productions from biomass.

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Uranium thermochemical cycle used for hydrogen production

  • Chen, Aimei;Liu, Chunxia;Liu, Yuxia;Zhang, Lan
    • Nuclear Engineering and Technology
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    • v.51 no.1
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    • pp.214-220
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    • 2019
  • Thermochemical cycles have been predominantly used for energy transformation from heat to stored chemical free energy in the form of hydrogen. The thermochemical cycle based on uranium (UTC), proposed by Oak Ridge National Laboratory, has been considered as a better alternative compared to other thermochemical cycles mainly due to its safety and high efficiency. UTC process includes three steps, in which only the first step is unique. Hydrogen production apparatus with hectogram reactants was designed in this study. The results showed that high yield hydrogen was obtained, which was determined by drainage method. The results also indicated that the chemical conversion rate of hydrogen production was in direct proportion to the mass of $Na_2CO_3$, while the solid product was $Na_2UO_4$, instead of $Na_2U_2O_7$. Nevertheless the thermochemical cycle used for hydrogen generation can be closed, and chemical compounds used in these processes can also be recycled. So the cycle with $Na_2UO_4$ as its first reaction product has an advantage over the proposed UTC process, attributed to the fast reaction rate and high hydrogen yield in the first reaction step.

Studying Thermochemical Conversion of Sm2O3 to SmCl3 using AlCl3 in LiCl-KCl Eutectic Melt

  • Samanta, Nibedita;Chandra, Manish;Maji, S.;Venkatesh, P.;Annapoorani, S.;Jain, Ashish
    • Journal of Electrochemical Science and Technology
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    • v.13 no.2
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    • pp.279-291
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    • 2022
  • In this report the thermochemical conversion of Sm2O3 to SmCl3 using AlCl3 in LiCl-KCl melt at 773 K is discussed. The final product was a mixture of SmCl3, Al2O3, unreacted Sm2O3 and AlCl3 in the chloride melt. The electrochemical attributes of the mixture was analyzed with cyclic voltammetry (CV) and square wave voltammetry (SWV). The crystallographic phases of the mixture were studied with X-ray diffraction (XRD) technique. The major chemical conversion was optimized by varying the effective parameters, such as concentrations of AlCl3, duration of reaction and the amount of LiCl-KCl salt. The extent of conversion and qualitative assessment of efficiency of the present protocol were evaluated with fluorescence spectroscopy, UV-Vis spectrophotometry and inductively coupled plasma atomic emission spectroscopy (ICP-AES) studies of the mixture. Thus, a critical assessment of the thermochemical conversion efficiency was accomplished by analysing the amount of SmCl3 in LiCl-KCl melt. In the process, a conversion efficiency of 95% was achieved by doubling the stoichiometric requirement of AlCl3 in 50 g of LiCl-KCl salt. The conversion reaction was found to be very fast as the reaction reached equilibrium in 15 min.

Thermodynamic Analysis of Thermochemical Process for Water Splitting (고온열 이용 공정의 열역학적 해석)

  • Kim, Jong-Won;Son, Hyun-Myung;Lee, Sana-Ho;Sim, Kyu-Sung;Jung, Kwang-Deog
    • Journal of Hydrogen and New Energy
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    • v.13 no.3
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    • pp.204-213
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    • 2002
  • In this work, hydrogen production by a 2-step water-spritting thermochemical cycle based on metal oxides redox pairs was investigated on the bases of the thermodynamics and technical feasibility. Also, a 2nd-law analysis performed on the closed cyclic process indicates a maximum exergy conversion efficiency of 7.1% when using a solar cavity-receiver operated at 2300K and air/Fe3O4 molar ratio = 10.

Improvement of the Thermochemical water-splitting IS Process Using the Membrane Technology (분리막 기술을 이용한 열화학적 수소제조 IS[요오드-황] 프로세스의 개선)

  • Hwang, Gab-Jin;Kim, Jong-Won;Sim, Kyu-Sung
    • Journal of Hydrogen and New Energy
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    • v.13 no.3
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    • pp.249-258
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    • 2002
  • Thermochemical water-splitting IS(Iodine-Sulfur) process has been investigating for large-scale hydrogen production. For the construction of an efficient process scheme, two kinds of membrane technologies are under investigating to improve the hydrogen producing HI decomposition step. One is a concentration of HI in quasi-azeotropic HIx ($HI-H_2O-I_2$) solution by elecro-electrodialysis. It was confirmed that HI concentrated from the $HI-H_2O-I_2$ solution with a molar ratio of 1:5:1 at $80^{\circ}C$. The other is a membrane reactor to enhance the one-pass conversion of thermal decomposition reaction of gaseous hydrogen iodide (HI). It was found from the simulation study that the conversion of over 0.9 would be attainable using the membrane reactor using the gas permeation properties of the prepared silica hydrogen permselective membrane by chemical vapor deposition (CVD). Design criterion of the membrane reactor was also discussed.

The Preparation Characteristics of Hydrogen Permselective Membrane in IS Process of Nuclear Hydrogen Production (원자력 수소제조 IS 공정의 수소분리막 제조 특성)

  • Son, Hyo-Seok;Choe, Ho-Sang;Kim, Jeong-Min;Hwang, Gap-Jin;Park, Ju-Sik;Bae, Gi-Gwang
    • Proceedings of the Membrane Society of Korea Conference
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    • 2005.11a
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    • pp.119-123
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    • 2005
  • The thermochemical splitting of water has been proposed as a clean method for hydrogen production. The IS process is one of the thermochemical water splitting processes using iodine and sulfur as reaction agents. HI decomposition procedure to obtain hydrogen is one of the key operations in the process, because equilibrium conversion of HI is low (22% at $450^{\circ}C$). The silica membranes prepared by CVD. method were applied to the decomposition reaction of HI vapor. The permeation characteristics of hydrogen and nitrogen belong to the Knudsen flow pattern.

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Performance Analysis of Adiabatic Reactor in Thermochemical Carbon Dioxide Methanation Process for Carbon Neutral Methane Production (탄소중립 메탄 생산을 위한 열화학적 이산화탄소 메탄화 공정의 단열 반응기 성능 분석)

  • JINWOO KIM;YOUNGDON YOO;MINHYE SEO;JONGMIN BAEK;SUHYUN KIM
    • Journal of Hydrogen and New Energy
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    • v.34 no.3
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    • pp.316-326
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    • 2023
  • Development of carbon-neutral fuel production technologies to solve climate change issues is progressing worldwide. Among them, methane can be produced through the synthesis of hydrogen produced by renewable energy and carbon dioxide captured through a CO2 methanation reaction, and the fuel produced in this way is called synthetic methane or e-methane. The CO2 methanation reaction can be conducted via biological or thermochemical methods. In this study, a 30 Nm3/h thermochemical CO2 methanation process consisting of an isothermal reactor and an adiabatic reactor was used. The CO2 conversion rate and methane concentration according to the temperature measurement results at the center and outside of the adiabatic reactor were analyzed. The gas flow into the adiabatic reactor was found to reach equilibrium after about 1.10 seconds or more by evaluating the residence time. Furthermore, experimental and analysis results were compared to evaluate performance of the reactor.

Thermochemical Conversion of Oil sand Bitumen in Delayed Coking Reactor (코킹 공정(工程)을 이용한 오일샌드 역청(瀝靑)의 열화학(熱化學)적 전환(轉換))

  • Lee, See-Hoon;Yoon, Sang-Jun;Lee, Jae-Goo;Kim, Jae-Ho
    • Resources Recycling
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    • v.17 no.3
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    • pp.35-41
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    • 2008
  • The study of coking technology to upgrade oil sand bitumen which is considered as alternative fuel was performed by using thermogravity analyzer and delayed coking reactor(600ml). To analyzed and compared coking characteristics of oil sand bitumen, the reactivities of oil sand bitumen were measured in the TGA. At the temperature conditions of $400{\sim}550^{\circ}C$ and the temperature rising velocity of $50^{\circ}C/min$. the termination time of coking reaction and conversion efficiencies increased with an increase of bed temperature. However the increase rate decreased over $450^{\circ}C$. So the coking reaction with oil sand bitumen might be over $450^{\circ}C$. Also the termination time decreased with increasing the temperature rising velocity. But the content of coke increased with increasing temperature rising velocity. At the experiments in the delayed coker, the temperature condition at maximum oil yield was $475^{\circ}C$ and the fuel properties of oil from coking reaction was almost equal with conventional diesel. It was verified that the coking process might be useful process to upgrade the oil sand bitumem by using API and SIMDAS.

2-Step Thermochemical Water Splitting on a Active Material Washcoated Monolith Using a Solar Simulator as Heat Source (인공태양을 이용한 모노리스 적용 반응기에서 2단계 열화학적 물분해 연구)

  • Kang, Kyoung-Soo;Kim, Chang-Hee;Park, Chu-Sik
    • Journal of Hydrogen and New Energy
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    • v.18 no.2
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    • pp.109-115
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    • 2007
  • Solar energy conversion to hydrogen was carried out via a two-step thermochemical water splitting using metal oxide redox pair. To simulate the solar radiation, a 7 kW short arc Xe-lamp was used. Partially reduced iron oxide and cerium oxide have the water splitting ability, respectively. So, $Fe_3O_4$ supported on $CeO_2$ was selected as the active material. $Fe_3O_4/CeO_2$(20 wt/80 wt%) was prepared by impregnation method, then the active material was washcoated on the ceramic honeycomb monolith made of mullite and cordierite. Oxygen was released at the reduction step($1673{\sim}1823\;K$) and hydrogen was produced from water at lower temperature($873{\sim}1273\;K$). The result demonstrate the possibility of the 2-step thermochemical water splitting hydrogen production by the active material washcoated monolith. And hydrogen and oxygen was produced separately without any separation process in a monolith installed reactor. But the SEM and EDX analysis results revealed that the support used in this experiment is not suitable due to the thermal instability and coating material migration.

Recent Development of Thermo-chemical Conversion Processes with Fluidized Bed Technologies (유동층 공정을 이용한 열화학적 전환 공정의 최신 개발 동향)

  • Hyun Jun Park;Seung Seok Oh;Olusola Nafiu Olanrewaju;Jester Lih Jie Ling;Chul Seung Jeong;Han Saem Park;See Hoon Lee
    • Korean Chemical Engineering Research
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    • v.61 no.1
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    • pp.8-18
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    • 2023
  • Increasing of energy demand due to the rapid growth of global population and the development of world economy has inevitably resulted in the continuously increase of fossil fuel usage in the world. However, highly dependence on fossil fuels has necessarily brought about critical environmental issues and challenges such as severe air pollutions and rapid global warming. In order to settle these environmental and energy problems, clean energy generations in the conventional combustion processes have widely adapted in the world. In particular, novel thermochemical conversion processes such as pyrolysis and gasification have rapidly been applied for generating clean energy. Fluidized bed technologies having advantages such as various fuel use, easy continuous operation, high heat and material transfer, isothermal operation, and lower operation temperature are widely adopted and used because they are suitable for thermochemical energy conversion. The latest research trends and important findings in the thermo-chemical conversion process with fluidized bed technologies are summarized in this review. Also, the need for research such as layered materials and substances to reduce fine dust (biomass, natural resource waste, etc.) was suggested. Through this, it is intended to increase interest and understanding in fluidized bed technology and to present directions for solving future challenges in fluidized bed process technology development.