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Journal of Energy Chemistry 2019年第2期28卷 50-57页

作者： Fei Huang Ming Tian Yanyan Zhu Xiaodong Wang Aiqin Wang Lin Li Jian Lin Junhu Wang Fujian Normal University State Key Laboratory of Catalysis Dalian Institute of Chemical PhysicsChinese Academy of Sciences College of Chemical Engineering Northwest University

While Fe-based oxygen carriers(OC) are regarded to be promising for chemical Looping combustion(CLC),the decrease of CO_2 selectivity during deep reduction process and the severe agglomeration of Fe_2O_3 often occur after multiple redox cycles due to the low oxygen mobility.Herein,Fe-substituted Bahexaaluminates(Ba Fe_xAl_(12)– xO_(19),denoted as BF_xA-H,x = 1 and 2) prepared by a modified two-step method exhibited not only higher amount of converted oxygen(Ot) and CH_4 conversion(77% and 81% vs.17%and 75%) than those prepared by the traditional co-precipitation method(BF_xA-C,x = 1 and 2) but also high CO_2 selectivity above 92% during the nearly whole reduction from Fe^(3+) to Fe^(2+).Furthermore,the BFxA-H exhibited the excellent recyclability during 50 cycles.The better performance was ascribed to the markedly enhanced oxygen mobility which resulted from dominant occupancy of Fe cations in Al(5) sites(Fe^5: 71% and 70% vs.49% and 41%) in mirror planes of hexaaluminate leading to larger amount of lattice oxygen coordinated with Fe^5(O–Fe^5)(0.45 and 0.85 mmol/g vs.0.31 and 0.50 mmol/g).The improvement of oxygen mobility also favored the preservation of chemical state of Fe cations in hexaaluminate structure in the re-oxidation step,resulting in the excellent recyclability of BF_xA-H.

关键词： CO2 capture Chemical Looping CH4 conversion Oxygen mobility Fe-based hexaaluminate

Solar chemical Looping reforming of methane combined with isothermal H2O/CO2 splitting using ceria oxygen carrier for syngas production

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Journal of Energy Chemistry 2020年第2期29卷 60-72页

作者： Srirat Chuayboon Stéphane Abanades Sylvain Rodat Processes Materials and Solar Energy LaboratoryPROMES-CNRSFont-Romeu 66120France Department of Mechanical Engineering King Mongkut's Institute of Technology LadkrabangPrince of Chumphon CampusChumphon 86160Thailand Universite Grenoble Alpes Le-Bourget-du-Lac F-73375France CEA-LJTEN Laboratoire des Systemes Solaires Haute Temperature(LSHT) Grenoble F-38054France

The chemical Looping reforming of methane through the nonstoichiometric ceria redox cycle(CeO2/CeO2-δ) has been experimentally investigated in a directly irradiated solar reactor to convert both solar energy and methane to syngas in the temperature range 900–1050 °C. Experiments were carried out with different ceria shapes via two-step redox cycling composed of endothermic partial reduction of ceria with methane and complete exothermic re-oxidation of reduced ceria with H2 O/CO2 at the same operating temperature, thereby demonstrating the capability to operate the cycle isothermally. A parametric study considering different ceria macrostructure variants(ceria packed powder, ceria packed powder mixed with inert Al2 O3 particles, and ceria reticulated porous foam) and operating parameters(methane flow-rate, reduction temperature, or sintering temperature) was conducted in order to unravel their impact on the bed-averaged oxygen non-stoichiometry(δ), syngas yield, methane conversion, and solar reactor performance. The ceria cycling stability was also experimentally investigated to demonstrate repeatable syngas production by alternating the flow between CH4 and H2 O(or CO2). A decrease in sintering temperature of the ceria foam was beneficial for increasing syngas selectivity, methane conversion,and reactor performance. Increasing both CH4 concentration and reduction temperature enhanced δ with the maximum value up to 0.41 but concomitantly favored CH4 cracking reaction. The ceria reticulated porous foam showed better performance in terms of effective heat transfer, due to volumetric absorption of concentrated solar radiation and uniform heating with lower solar power consumption, thereby promoting the solar-to-fuel energy conversion efficiency that reached up to 5.60%. The energy upgrade factor achieved during cycle was up to 1.19. Stable patterns in the δ and syngas yield for consecutive cycles with the ceria foam validated material performance stability.

关键词： Chemical Looping Methane reforming Ceria structure Concentrated solar power Syngas production H2O/CO2 splitting

CaSO_4载氧体-煤化学链气化过程气化剂的影响（英文）

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Chinese Journal of Chemical Engineering 2014年第Z1期22卷 1208-1214页

作者：刘永卓贾伟华郭庆杰 Hojung Ryu College of Chemical Engineering Qingdao University of Science & TechnologyKey Laboratory of Clean Chemical Processing Engineering of Shandong Province Climate Change Technology Research Division Korea Institute of Energy Research

The chemical Looping gasification uses an oxygen carrier for solid fuel gasification by supplying insufficient lattice oxygen. The effect of gasifying medium on the coal chemical Looping gasification with Ca SO4 as oxygen carrier is investigated in this paper. The thermodynamical analysis indicates that the addition of steam and CO2 into the system can reduce the reaction temperature, at which the concentration of syngas reaches its maximum value.Experimental result in thermogravimetric analyzer and a fixed-bed reactor shows that the mixture sample goes through three stages, drying stage, pyrolysis stage and chemical Looping gasification stage, with the temperature for three different gaseous media. The peak fitting and isoconversional methods are used to determine the reaction mechanism of the complex reactions in the chemical Looping gasification process. It demonstrates that the gasifying medium(steam or CO2) boosts the chemical Looping process by reducing the activation energy in the overall reaction and gasification reactions of coal char. However, the mechanism using steam as the gasifying medium differs from that using CO2. With steam as the gasifying medium, parallel reactions occur in the beginning stage, followed by a limiting stage shifting from a kinetic to a diffusion regime. It is opposite to the reaction mechanism with CO2 as the gasifying medium.

关键词： Chemical Looping gasification Ca SO4 oxygen carrier Reaction mechanism Syngas generation

Impact of Looping on premalignant polyp detection during colonoscopy

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World Journal of Gastrointestinal Endoscopy 2022年第11期14卷 694-703页

作者： Osamu Toyoshima Toshihiro Nishizawa Shuntaro Yoshida Tatsuya Matsuno Toru Arano Ryo Kondo Kazunori Kinoshita Yuki Yasumi Yosuke Tsuji Mitsuhiro Fujishiro Department of Gastroenterology Toyoshima Endoscopy ClinicTokyo 157-0066Japan Department of Gastroenterology and Hepatology International University of Health and WelfareNarita HospitalNarita 286-8520Japan Department of Obstetrics and Gynecology Seijo Kinoshita HospitalTokyo 157-0066Japan Department of Internal Medicine Yasumi HospitalMorioka 028-4125Japan Department of Gastroenterology Graduate School of MedicineThe University of TokyoTokyo 113-8655Japan

BACKGROUND The presence of premalignant polyps on colonoscopy is an indicator of metachronous colorectal cancer.Looping during colonoscopy is associated with old age,female sex,and colonoscopy insertion time.However,the clinical significance of Looping is not fully understood.We aimed to clarify the effect of Looping on colorectal premalignant polyp detection.AIM To assess the effects of Looping on premalignant polyp detection using logistic regression analyses.METHODS We retrospectively investigated patients who underwent colonoscopy at Toyoshima Endoscopy Clinic between May,2017 and October,2020.From the clinic’s endoscopy database,we extracted data on patient age,sex,endoscopist-assessed Looping,colonoscopy duration,endoscopist experience,detection rate,and number of premalignant polyps.RESULTS We assessed 12259 patients(mean age,53.6 years;men,50.7%).Looping occurred in 54.3%of the patients.Mild and severe Looping were noted in 4399 and 2253 patients,respectively.The detection rates of adenomas,advanced adenomas,high-risk adenomas,clinically significant serrated polyps(CSSPs),and sessile serrated lesions(SSLs)were 44.7%,2.0%,9.9%,8.9%and 3.5%,respectively.The mean numbers of adenomas and SSLs were 0.82 and 0.04,respectively.The detection rates of adenomas,high-risk adenomas,and CSSPs increased with Looping severity(all PLooping severity(PLooping(PLooping severity was independently associated with high detection rates of premalignant polyps.Therefore,Looping may predict the risk of metachronous colorectal cancer.Endoscopists should carefully examine the colorectum of patients with Looping.

关键词： Looping Colorectal polyp Colonoscopy Adenoma Serrated polyp Colorectal neoplasm

Hydrogen Production by Chemical Looping Gasification of Corn Stalk Driven by a tert-Butanol Solution

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Chemical Research in Chinese Universities 2019年第6期35卷 1012-1017页

作者： QIN Wu CHEN Shubo ZHU Jinqi ZHANG Maodong XIAO Xianbin National Engineering Laboratory for Biomass Power Generation Equipment North China Electric Power UniversityBeijing 102206P.R.China

The purpose of this work is to convert organic wastewater into oxidants(H2O and CO2)to promote biomass gasification during the chemical Looping process to achieve high-H2/CO-ratio syngas.A tert-butanol solution was selected as the model organic wastewater to generate enough H2O and CO2 to promote corn stalk chemical Looping gasification(CLG).A series of CLG experiments was conducted at 850℃ under various degrees of oxygen excess(Ω).AnΩof approximately 0.9 led to the highest hydrogen yield and fixed carbon conversion compared with the other cases.Chemometrics and thermodynamic analysis further validated the possibility of corn stalk CLG using a tert-butanol solution.The results show that CLG of biomass-organic wastewater can both treat organic waste and promote chemical Looping processes.

关键词： Chemical Looping gasification Hydrogen energy Biomass Wastewater,Oxygen carrier

Chemical Looping combustion of coal in interconnected fluidized beds

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Science China(Technological Sciences) 2007年第2期50卷 230-240页

作者： SHEN LaiHong ZHENG Min XIAO Jun ZHANG Hui XIAO Rui Key Laboratory of Clean Coal Power Generation and Combustion Technology of Ministry of Education Southeast UniversityNanjing 210096China

Chemical Looping combustion is the indirect combustion by use of oxygen carrier. It can be used for CO2 capture in power generating processes. In this paper, chemical Looping combustion of coal in interconnected fluidized beds with inherent separation of CO2 is proposed. It consists of a high velocity fluidized bed as an air reactor in which oxygen carrier is oxidized, a cyclone, and a bubbling fluidized bed as a fuel reactor in which oxygen carrier is reduced by direct and indirect reactions with coal. The air reactor is connected to the fuel reactor through the cyclone. To raise the high carbon conversion efficiency and separate oxygen carrier particle from ash, coal slurry instead of coal particle is introduced into the bottom of the bubbling fluidized bed. Coal gasification and the reduction of oxygen carrier with the water gas take place simultaneously in the fuel reactor. The flue gas from the fuel reactor is CO2 and water. Almost pure CO2 could be obtained after the con- densation of water. The reduced oxygen carrier is then returned back to the air reactor, where it is oxidized with air. Thermodyanmics analysis indicates that NiO/Ni oxygen carrier is the optimal one for chemical Looping combustion of coal. Simulation of the processes for chemical Looping combustion of coal, including coal gasification and reduction of oxygen carrier, is carried out with Aspen Plus software. The effects of air reactor temperature, fuel reactor temperature, and ratio of water to coal on the composition of fuel gas, recirculation of oxygen carrier par- ticles, etc., are discussed. Some useful results are achieved. The suitable tem- perature of air reactor should be between 1050―1150℃and the optimal temperature of the fuel reactor be between 900―950℃.

关键词： chemical Looping combustion coal interconnected fluidized beds CO2 separation

Symbolic Computation and Graphic Presentation of Magneto-Static Field and Its Associated Vector Potential for a Steady Looping Current

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Journal of Electromagnetic Analysis and Applications 2011年第5期3卷 172-177页

作者： Haiduke Sarafian University College The Pennsylvania State University

With the advent of Computer Algebra System (CAS) such as Mathematica [1], challenging symbolic longhand calcula-tions can effectively be performed free of error and at ease. Mathematica’s integrated features allow the investigator to combine the needed symbolic, numeric and graphic modules all in one interactive environment. This assists the author to focus on interpreting the output rather than exerting the efforts of relating the scattered separate modules. In this note the author, utilizing these three features, explores the magneto-static field and its associated vector potential of a steady Looping current. In particular by deploying the numeric features of Mathematica the exact value of the vector potential of the Looping current conducive to its 3D graph is presented.

关键词： Magneto-Static Field of a Looping Current Vector Potential Symbolic Computation Mathematica

Recent progress towards mild-condition ammonia synthesis

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Journal of Energy Chemistry 2019年第9期28卷 25-36页

作者： Qianru Wang Jianping Guo Ping Chen Dalian National Laboratory for Clean Energy Dalian Institute of Chemical Physics Chinese Academy of Sciences Dalian 116023 Liaoning China University of Chinese Academy of Sciences Beijing 100049 China Collaborative Innovation Center of Chemistry for Energy Materials Dalian 116023 Liaoning China

Ammonia is essential for food and energy.Industrial ammonia synthesis via Haber–Bosch process is energy-intensive and releases large amount of CO2.Increasing research efforts are devoted to "green"ammonia synthesis.The present article reviews the recent progress in the fields of thermocatalytic, electrocatalytic, photocatalytic and chemical Looping processes for dinitrogen reduction towards ammonia formation and discusses the challenges borne for mild-condition synthesis.

关键词： Ammonia synthesis Thermocatalytic process Electrocatalytic process Photocatalytic process Chemical Looping process

Thermodynamic Analysis and Synthesis Gas Generation by Chemical-Looping Gasification of Biomass with Nature Hematite as Oxygen Carriers

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Journal of Sustainable Bioenergy Systems 2013年第1期3卷 33-39页

作者： Zhen Huang Fang He Anqing Zheng Kun Zhao Sheng Chang Xinai Li Haibin Li Zengli Zhao Key Laboratory of Renewable Energy and Gas Hydrate of Chinese Academy of Sciences Guangzhou Institute of Energy Conversion Chinese Academy of Sciences Guangzhou China

Thermodynamic parameters of chemical reactions in the system were carried out through thermodynamic analysis. According to the Gibbs free energy minimization principle of the system, equilibrium composition of the reactions of chemical-Looping gasification (CLG) of biomass with natural hematite (Fe2O3) as oxygen carrier were analyzed using commercial software of HSC Chemistry 5.1. The feasibility of the CLG of biomass with hematite was experimental verified in a lab-scale bubbling fluidized bed reactor using argon as fluidizing gas. It was indicated the experimental results were consistent with the theoretical analysis. The presence of oxygen carrier gave a significant effect on the biomass conversion and improved the synthesis gas yield obviously. It was observed that the gas content of CO and H2 was over 70% in CLG of biomass. The reduced hematite particles mainly existed in form of FeO. It was showed that the reduction of natural hematite with biomass proceeds in a stepwise manner from Fe2O3 →Fe3O4→ FeO. Reduction product of natural hematite can be restored the lattice oxygen by oxidation with air.

关键词： Thermodynamics Synthesis Gas Natural Hematite Oxygen Carriers Biomass Chemical Looping Gasification

Regulation of MYC gene expression by aberrant Wnt/β-catenin signaling in colorectal cancer

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World Journal of Biological Chemistry 2015年第4期6卷 290-300页

作者： Sherri Rennoll Gregory Yochum Department of Biochemistry and Molecular Biology the Pennsylvania State University College of Medicine

The Wnt/β-catenin signaling pathway controls intestinal homeostasis and mutations in components of this pathway are prevalent in human colorectal cancers(CRCs).These mutations lead to inappropriate expression of genes controlled by Wnt responsive DNA elements(WREs). T-cell factor/Lymphoid enhancer factor transcription factors bind WREs and recruit the β-catenin transcriptional co-activator to activate target gene expression. Deregulated expression of the c-MYC proto-oncogene(MYC) by aberrant Wnt/β-catenin signaling drives colorectal carcinogenesis. In this review,we discuss the current literature pertaining to the identification and characterization of WREs that control oncogenic MYC expression in CRCs. A common theme has emerged whereby these WREs often map distally to the MYC genomic locus and control MYC gene expression through long-range chromatin loops with the MYC proximal promoter. We propose that by determining which of these WREs is critical for CRC pathogenesis,novel strategies can be developed to treat individuals suffering from this disease.

关键词： Wnt β-catenin Chromatin Looping Wnt responsive DNA