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Nano-structured hemoglobin-based oxygen carriers: from properties, methemoglobin suppression to long circulation in blood
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作者 YUAN Yuan ZHANG Xiao-lan +4 位作者 LIU Chang-sheng ZHAO Jian SHENG Yan SHAN Xiao-qian XU Feng 《东南大学学报(医学版)》 CAS 2011年第1期72-82,共11页
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Thermogravimetric characteristics of corn straw and bituminous coal copyrolysis based the ilmenite oxygen carriers
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作者 Pengxing Yuan Xiude Hu +2 位作者 Jingjing Ma Tuo Guo Qingjie Guo 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2024年第4期8-15,共8页
Herein,the co-pyrolysis reaction characteristics of corn straw(CS)and bituminous coal in the presence of ilmenite oxygen carriers(OCs)are investigated via thermogravimetry coupled with mass spectrometry.The results re... Herein,the co-pyrolysis reaction characteristics of corn straw(CS)and bituminous coal in the presence of ilmenite oxygen carriers(OCs)are investigated via thermogravimetry coupled with mass spectrometry.The results reveal that the participation of OCs weakens the devolatilization intensity of co-pyrolysis.When the CS blending ratio is<50%,the mixed fuel exhibits positive synergistic effects.The fitting results according to the Coats-Redfern integral method show that the solid-solid interaction between OCs and coke changes the reaction kinetics,enhancing the co-pyrolysis reactivity at the high-temperature zone(750-950C).The synergistic effect is most prominent at a 30%CS blending ratio,with copyrolysis activation energy in the range of 26.35-40.57 kJ·mol^(-1). 展开更多
关键词 oxygen carrier CO-PYROLYSIS BIOMASS COAL
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Ethane Chemical Looping Oxidative Dehydrogenation to Ethylene over Co_(2)O_(3)(Fe_(2)O_(3),NiO)/LaCoO_(3) Oxygen Carriers
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作者 Liang Hao Meng Jinhong +1 位作者 Sun Jie Wei Dongkai 《China Petroleum Processing & Petrochemical Technology》 SCIE CAS CSCD 2024年第3期33-41,共9页
Ethane chemical looping oxidative dehydrogenation(CL-ODH)to ethylene is a new technology for converting ethane to ethylene.In the current study MeO/LaCoO_(3)(MeO=Fe_(2)O_(3),NiO or Co_(2)O_(3))composite metal oxides w... Ethane chemical looping oxidative dehydrogenation(CL-ODH)to ethylene is a new technology for converting ethane to ethylene.In the current study MeO/LaCoO_(3)(MeO=Fe_(2)O_(3),NiO or Co_(2)O_(3))composite metal oxides were prepared via citrate gel and impregnation methods,and used as oxygen carriers for CL-ODH.X-ray diffraction results indicated that all oxygen carriers had a perovskite structure even after eight redox cycles.Under a reaction temperature of 650°C,a reaction pressure of 0.1 MPa,and a weight hourly space velocity(WHSV)of 7500 mL/(g·h),ethane conversion over Co_(2)O_(3)/LaCoO_(3) reached 100%and ethylene selectivity reached 60%,both of which were better than corresponding values attained over Fe_(2)O_(3)/LaCoO_(3) and NiO/LaCoO_(3).Ethylene selectivity remained stable for 80 cycles over Co_(2)O_(3)/LaCoO_(3),then decreased gradually after 80 cycles.X-ray photoelectron spectroscopy results and evaluation results indicated that lattice oxygen and O_(2)2-had a direct relationship with ethane conversion and ethylene selectivity.Co_(2)O_(3)/LaCoO_(3) exhibited a strong capacity to release and absorb oxygen,mainly due to interaction between Co_(2)O_(3) and LaCoO_(3). 展开更多
关键词 chemical looping oxidative dehydrogenation ETHANE ETHYLENE oxygen carrier PEROVSKITE
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Advancements in biomass gasification research utilizing iron-based oxygen carriers in chemical looping:A review
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作者 Yonghong Niu Zhengyang Chi Ming Li 《Materials Reports(Energy)》 EI 2024年第3期35-48,共14页
Biomass,recognized as renewable green coal,is pivotal for energy conservation,emission reduction,and dualcarbon objectives.Chemical looping gasification,an innovative technology,aims to enhance biomass utilization eff... Biomass,recognized as renewable green coal,is pivotal for energy conservation,emission reduction,and dualcarbon objectives.Chemical looping gasification,an innovative technology,aims to enhance biomass utilization efficiency.Using metal oxides as oxygen carriers regulates the oxygen-to-fuel ratio to optimize synthesis product yields.This review examines various oxygen carriers and their roles in chemical looping biomass gasification,including natural iron ore types,industrial by-products,cerium oxide-based carriers,and core-shell structures.The catalytic,kinetic,and phase transfer properties of iron-based oxygen carriers are analyzed,and their catalytic cracking capabilities are explored.Molecular interactions are elucidated and system performance is optimized by providing insights into chemical looping reaction mechanisms and strategies to improve carrier efficiency,along with discussing advanced techniques such as density functional theory(DFT)and reactive force field(ReaxFF)molecular dynamics(MD).This paper serves as a roadmap for advancing chemical looping gasification towards sustainable energy goals. 展开更多
关键词 Chemical looping gasification Iron based oxygen carrier Preparation of oxygen carrier system
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Optimizing the sulfur-resistance and activity of perovskite oxygen carrier for chemical looping dry reforming of methane
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作者 Yuelun Li Dong Tian +6 位作者 Lei jiang Huicong Zuo LiNan Huang Mingyi Chen Jianchun Zuo Hua Wang Kongzhai Li 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2024年第9期259-271,共13页
Perovskite oxides has been attracted much attention as high-performance oxygen carriers for chemical looping reforming of methane,but they are easily inactivated by the presence of trace H_(2)S.Here,we propose to modu... Perovskite oxides has been attracted much attention as high-performance oxygen carriers for chemical looping reforming of methane,but they are easily inactivated by the presence of trace H_(2)S.Here,we propose to modulate both the activity and resistance to sulfur poisoning by dual substitution of Mo and Ni ions with the Fe-sites of LaFeO_(3)perovskite.It is found that partial substitution of Ni for Fe substantially improves the activity of LaFeO_(3)perovskite,while Ni particles prefer to grow and react with H_(2)S during the long-term successive redox process,resulting in the deactivation of oxygen carriers.With the presence of Mo in LaNi_(0.05)Fe_(0.95)O_(3−σ)perovskite,H_(2)S preferentially reacts with Mo to generate MoS_(2),and then the CO_(2)oxidation can regenerate Mo via removing sulfur.In addition,Mo can inhibit the accumulation and growth of Ni,which helps to improve the redox stability of oxygen carriers.The LaNi_(0.05)Mo_(0.07)Fe_(0.88)O_(3−σ)oxygen carrier exhibits stable and excellent performance,with the CH_(4)conversion higher than 90%during the 50 redox cycles in the presence of 50 ppm H_(2)S at 800℃.This work highlights a synergistic effect in the perovskite oxides induced by dual substitution of different cations for the development of high-performance oxygen carriers with excellent sulfur tolerance. 展开更多
关键词 Perovskite oxygen carriers Chemical looping reforming Sulfur-resistance Dual substitution SYNGAS
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CO_(2)capture costs of chemical looping combustion of biomass:A comparison of natural and synthetic oxygen carrier
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作者 Benjamin Fleiß Juraj Priscak +3 位作者 Martin Hammerschmid Josef Fuchs Stefan Müller Hermann Hofbauer 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2024年第5期296-310,共15页
Chemical looping combustion has the potential to be an efficient and low-cost technology capable of contributing to the reduction of the atmospheric concentration of CO_(2) in order to reach the 1.5/2°C goal and ... Chemical looping combustion has the potential to be an efficient and low-cost technology capable of contributing to the reduction of the atmospheric concentration of CO_(2) in order to reach the 1.5/2°C goal and mitigate climate change.In this process,a metal oxide is used as oxygen carrier in a dual fluidized bed to generate clean CO_(2) via combustion of biomass.Most commonly,natural ores or synthetic materials are used as oxygen carrier whereas both must meet special requirements for the conversion of solid fuels.Synthetic oxygen carriers are characterized by higher reactivity at the expense of higher costs versus the lower-cost natural ores.To determine the viability of both possibilities,a techno-economic comparison of a synthetic material based on manganese,iron,and copper to the natural ore ilmenite was conducted.The synthetic oxygen carrier was characterized and tested in a pilot plant,where high combustion efficiencies up to 98.4%and carbon capture rates up to 98.5%were reached.The techno-economic assessment resulted in CO_(2) capture costs of 75 and 40€/tCO_(2) for the synthetic and natural ore route respectively,whereas a sensitivity analysis showed the high impact of production costs and attrition rates of the synthetic material.The synthetic oxygen carrier could break even with the natural ore in case of lower production costs and attrition rates,which could be reached by adapting the production process and recycling material.By comparison to state-of-the-art technologies,it is demonstrated that both routes are viable and the capture cost of CO_(2) could be reduced by implementing the chemical looping combustion technology. 展开更多
关键词 Chemical looping combustion BECCS Techno-economic assessment CO_(2)capture costs oxygen carrier development Synthetic materials ILMENITE
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Chemical looping oxidative propane dehydrogenation controlled by oxygen bulk diffusion over FeVO_(4)oxygen carrier pellets 被引量:1
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作者 Hongbo Song Wei Wang +5 位作者 Jiachen Sun Xianhui Wang Xianhua Zhang Sai Chen Chunlei Pei Zhi-Jian Zhao 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2023年第1期409-420,共12页
The oxygen distribution and evolution within the oxygen carrier exert significant influence on chemical looping processes.This paper describes the influence of oxygen bulk diffusion within FeVO4 oxygen carrier pellets... The oxygen distribution and evolution within the oxygen carrier exert significant influence on chemical looping processes.This paper describes the influence of oxygen bulk diffusion within FeVO4 oxygen carrier pellets on the chemical looping oxidative propane dehydrogenation(CL-ODH).During CL-ODH,the oxygen concentration at the pellet surface initially decreased and then maintained stable before the final decrease.At the stage with the stable surface oxygen concentration,the reaction showed a stable C3H6 formation rate and high C3H6 selectivity.Therefore,based on Fick’s second law,the oxygen distribution and evolution in the oxygen carrier at this stage were further analyzed.It was found that main reactions of selective oxidation and over-oxidation were controlled by the oxygen bulk diffusion.C3H8 conversion rate kept decreasing during this stage due to the decrease of the oxygen flux caused by the decline of oxygen gradient within the oxygen carrier,while C3H6 selectivity increased due to the decrease of overoxidation.In addition,reaction rates could increase with the propane partial pressure due to the increase of the oxygen gradient within the oxygen carrier until the bulk transfer reached its limit at higher propane partial pressure.This study provides fundamental insights for the diffusion-controlled chemical looping reactions. 展开更多
关键词 Chemical looping DIFFUSION Reaction kinetics oxygen carriers OXIDATION
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Chemical looping catalytic gasification of biomass over active LaNixFe1-xO_(3)perovskites as functional oxygen carriers 被引量:4
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作者 Jingchun Yan Weidong Liu +3 位作者 Rong Sun Shouxi Jiang Shen Wang Laihong Shen 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2021年第8期146-156,共11页
Oxygen carriers(OCs)with perovskite structure are attracting increasing interests due to their redox tunability by introducing various dopants in the structure.In this study,LaNixFe1-xO3(x=0,0.1,0.3,0.5,0.7,1.0)perovs... Oxygen carriers(OCs)with perovskite structure are attracting increasing interests due to their redox tunability by introducing various dopants in the structure.In this study,LaNixFe1-xO3(x=0,0.1,0.3,0.5,0.7,1.0)perovskite OCs have been prepared by a citric acid–nitrate sol–gel method,characterized by means of X-ray diffraction(XRD)analysis and tested for algae chemical looping gasification in a fixed bed reactor.The effects of perovskite types,OC/biomass mass ratio(O/B),gasification temperature and water injection rate on the gasification performance were investigated.Lower Ni-doped(0≤x≤0.5)perovskites crystalized in the rhombohedra system which was isostructural with LaNiO3,while those with composition 0.5≤x≤1 crystalized in the orthorhombic system.Despite the high reactivity for LaNiO_(3),LaNi_(0.5)Fe_(0.5)O_(3)(LN5F5)was found to be more stable at a high temperature and give almost as good results as LaNiO_(3)in the formation of syngas.The relatively higher syngas yield of 0.833 m^(3)·kg^(-1) biomass was obtained under the O/B of 0.4,water injection rate of 0.3 ml·min^(-1) and gasification temperature at 850C.Continuous high yield of syngas was achieved during the first 5 redox cycles,while a slight decrease in the reactivity for LN5F5 after 5 cycles was observed due to the adhesion of small grains occurring on the surface of OCs.However,an obvious improvement in the gasification performance was attained for LN5F5 compared to raw biomass direct gasification,indicating that LN5F5 is a promising functional OC for chemical looping catalytic gasification of biomass. 展开更多
关键词 BIOMASS Chemical looping gasification oxygen carrier La-Ni-Fe perovskite CATALYSIS
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Layered Mg-Al spinel supported Ce-Fe-Zr-O oxygen carriers for chemical looping reforming 被引量:3
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作者 Jiangyong Yuan Yannan Zhao +4 位作者 Haiwen Xu Chunqiang Lu Kun Yang Xing Zhu Kongzhai Li 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2020年第10期2668-2676,共9页
A series of layered Mg-Al spinel supported Ce-Fe-Zr-O oxygen carriers were prepared for co-production of syngas and pure hydrogen via chemical looping steam reforming(CLSR).The presence of magnesium-aluminum layered d... A series of layered Mg-Al spinel supported Ce-Fe-Zr-O oxygen carriers were prepared for co-production of syngas and pure hydrogen via chemical looping steam reforming(CLSR).The presence of magnesium-aluminum layered double oxides(Mg Al-LDO)significantly increases the specific surface area of the mixed oxides,reduces the particle size of CeO2-based solid solution and promotes the dispersion of free Fe2O3.When reacting with methane,Mg Al-LDO supported oxygen carrier shows much lower temperature for methane oxidation than the pure CeFe-Zr-O sample,indicating enhanced low-temperature reactivity.Among different Ce-Fe-Zr-O(x)/Mg Al-LDO samples,the Ce-Fe-Zr-O(40 wt%)/Mg Al-LDO sample shows the best performance for the selective oxidation of methane to syngas and the H2 production by water splitting.After a long period of high temperature redox experiment,the Ce-Fe-Zr-O(40 wt%)/Mg Al-LDO oxygen carrier still shows high activity for syngas generation.The comparison on the morphology of the fresh and cycled oxygen carriers indicates that the Mg-Al spinel support still forms a stable skeleton structure with high dispersion of active components on the surface after the long-term cycling,which contributes to excellent redox stability of the Ce-Fe-Zr-O(40 wt%)/Mg Al-LDO oxygen carrier. 展开更多
关键词 Chemical looping reforming SYNGAS Hydrogen Ce-Fe-Zr-O(x)/MgAl-LDO oxygen carrier
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Thermodynamic Analysis and Synthesis Gas Generation by Chemical-Looping Gasification of Biomass with Nature Hematite as Oxygen Carriers 被引量:2
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作者 Zhen Huang Fang He +5 位作者 Anqing Zheng Kun Zhao Sheng Chang Xinai Li Haibin Li Zengli Zhao 《Journal of Sustainable Bioenergy Systems》 2013年第1期33-39,共7页
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 rea... 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. 展开更多
关键词 THERMODYNAMICS Synthesis Gas Natural HEMATITE oxygen carriers BIOMASS Chemical LOOPING GASIFICATION
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Syngas production from chemical looping reforming of ethanol over iron-based oxygen carriers: Theoretical analysis and experimental investigation 被引量:1
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作者 Atif Abdalazeez Wenju Wang Siddig Abuelgasim 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2021年第10期123-131,共9页
Chemical looping reforming(CLR)is a recent trend for syngas production,which has several merits compared to the conventional manner.One of the most important issues for CLR is to find low-cost material as oxygen carri... Chemical looping reforming(CLR)is a recent trend for syngas production,which has several merits compared to the conventional manner.One of the most important issues for CLR is to find low-cost material as oxygen carriers,so iron is a promising candidate.This paper contributes to testing the thermodynamic ability of iron-based oxygen carrier for chemical looping reforming of ethanol(CLRE).Iron thermodynamically investigated in temperature 100–1300℃and excess oxygen number(φ)0–4.It was found that the temperature andφhave an apparent effect on the gaseous composition produced from the process.Increases in temperature within the range of 100–1300℃enhanced syngas generated and reduced coke formation and CH4.Whereas,increasedφ,particularly at higher temperatures,had also enhanced syngas production as well as reduced coke formation.However,increasingφfor values beyond one had decreased syngas and not significantly reduced coke deposition.Moreover,an experimental investigation was carried out in a fixed bed reactor for more in-depth verification of iron ability as an oxygen carrier through using magnetite ore(mainly Fe3O4).It found that the effect of temperature on syngas production was consistent with that calculated thermodynamically,as syngas increased with raising the temperature through the CLRE. 展开更多
关键词 SYNGAS Chemical looping reforming Iron oxygen carrier ETHANOL Coke formation Thermodynamic analysis
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Performance of Ni-based, Fe-based and Co-based Oxygen Carriers in Chemical-Looping Hydrogen Generation 被引量:1
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作者 Liang Hao Zhang Xiwen +1 位作者 Fang Xiangchen Yuan Honggang 《China Petroleum Processing & Petrochemical Technology》 SCIE CAS 2013年第2期53-58,共6页
Ni-based, Fe-based and Co-based oxygen carriers with perovskite oxides used as the supports were prepared by citric acid complexation method, The oxygen carriers were characterized by thermal analysis, H2-temperature-... Ni-based, Fe-based and Co-based oxygen carriers with perovskite oxides used as the supports were prepared by citric acid complexation method, The oxygen carriers were characterized by thermal analysis, H2-temperature-programmed reduction and X-ray diffraction methods. Performance tests were evaluated through Chemical-Looping Hydrogen Genera- tion in a fixed-bed reactor operating at atmospheric pressure. The characterization results showed that all samples were composed of metal oxides and perovskite oxides. Performance results indicated that CH4 conversion over the oxygen car- riers decreased in the lbllowing order: NiO/LaNiO3〉Co203/LaCoO3〉Fe203/LaFeO3. The ability of NiO/LaNiO3 and F%O3/ LaFeO3 to decompose water was stronger than that of Co203/LaCoO3 as evidenced by our experiments. H2 amounting to 80 mL upon reacting on methane in every cycle could be completely oxidized by NiO/LaNiO3 at 900℃ in the period from the third cycle to the eighth cycle. 展开更多
关键词 Chemical-Looping Hydrogen Generation oxygen carrier perovskite oxide METHANE
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Copper-based oxygen carriers supported with alumina/lime for the chemical looping conversion of gaseous fuels
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作者 Syed K Haider María Erans +4 位作者 Felix Donat Lunbo Duan Stuart A Scott Vasilije Manovic Edward J Anthony 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2017年第5期891-901,共11页
Copper(Ⅱ) oxide in varying ratios was combined with either an alumina-based cement(Al300), or CaO derived from limestone as support material in a mechanical pelletiser. This production method was used to investig... Copper(Ⅱ) oxide in varying ratios was combined with either an alumina-based cement(Al300), or CaO derived from limestone as support material in a mechanical pelletiser. This production method was used to investigate its influence on possible mechanical and chemical improvements for oxygen carriers in chemical looping processes. These materials were tested in a lab-scale fluidised bed with CO or CH;as a reducing gas at 950 °C. As expected, the oxygen carriers containing a greater ratio of support material exhibited an enhanced crushing strength. Oxygen carriers comprised of a 1:3 ratio of support material to active CuO exhibited increased crushing strength by a minimum of 280% compared to pure CuO pellets.All oxygen carriers exhibited a high CO conversion yield and were fully reducible from CuO to Cu. For the initial redox cycle, Al300-supported oxygen carriers showed the highest fuel and oxygen carrier conversion. The general trend observed was a decline in conversion with an increasing number of redox cycles.In the case of CaO-supported oxygen carriers, all but one of the oxygen carriers suffered agglomeration.The agglomeration was more severe in carriers with higher ratios of CuO. Oxygen carrier Cu25Al75(75 wt% aluminate cement and 25 wt% CuO), which did not suffer from agglomeration, showed the highest attrition with a loss of approximately 8% of its initial mass over 25 redox cycles. The reducibility of the oxygen carriers was limited with CH;in comparison to CO. CH;conversion were 15%-25% and 50% for Cu25Ca75(25 wt% CuO and 75 wt% CaO) and Cu25Al75, respectively. Cu25Ca75 demonstrated improved conversion, whereas Cu25Al75 exhibited a trending decrease in conversion with increasing redox cycles. 展开更多
关键词 Chemical-looping oxygen carrier COPPER Carbon capture
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Insights into the intrinsic interaction between series of C1 molecules and surface of NiO oxygen carriers involved in chemical looping processes
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作者 Jinpeng Zhang Hongfeng Gao +4 位作者 Nini Yuan QiangWang YuhuaWu Yanli Sun Hongcun Bai 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2020年第11期2771-2777,共7页
Understanding and modulating the interaction between various reactive molecules and oxygen carriers are the key issue to achieve process intensification of chemical looping technology.C1 chemical molecules play an imp... Understanding and modulating the interaction between various reactive molecules and oxygen carriers are the key issue to achieve process intensification of chemical looping technology.C1 chemical molecules play an important role in many reactions involved with chemical looping processes.However,up to now,there is still a lack of systematic and in-depth understanding of the adsorption mechanism of C1 molecules on the surface of oxygen carriers(OCs).In this work,the intrinsic interaction between a series of C1 molecules composed of CH4,CO,CO2,CH3OH,HCHO and HCOOH and surface of Ni O OCs in the chemical looping process have been studied using density functional theory calculations.Various adsorption configurations of C1 molecules and also different adsorption sites of Ni O have been considered.The structural features of stable configuration of C1 molecules on the surface of NiO OCs have been obtained.Further,the interacted sites,types and strengths of C1 molecules on the surface of NiO have been directly pictured by the independent gradient model methods.Also,the nature of the interaction between C1 molecule and Ni O surface has been investigated with the aid of energy decomposition analysis from a quantitative view. 展开更多
关键词 oxygen carrier Chemical looping C1 chemistry Adsorption Molecular modeling DFT
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Selective oxidation of methane to syngas using Pr_(0.7)Zr_(0.3)O_(2-δ): Stability of oxygen carrier
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作者 杜云鹏 祝星 +2 位作者 王华 魏永刚 李孔斋 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2015年第4期1248-1253,共6页
Pr0.7Zr0.3O2-δ solid solution was prepared by co-precipitation method and used as an oxygen carrier in the selective oxidation of methane to syngas(methane/air redox process). The evolution on the physicochemical pro... Pr0.7Zr0.3O2-δ solid solution was prepared by co-precipitation method and used as an oxygen carrier in the selective oxidation of methane to syngas(methane/air redox process). The evolution on the physicochemical properties of Pr0.7Zr0.3O2-δ during the redox process was studied by means of X-ray diffraction(XRD), H2 temperature-programmed reduction(H2-TPR), O2temperature-programmed desorption(O2-TPD), Brunauer-Emmett-Teller(BET) surface area measurement and X-ray photoelectron spectroscopy(XPS) technologies. The results indicated that Pr0.7Zr0.3O2-δ solid solution showed the high activity for the methane conversion to syngas with a high CO selectivity in the range of 83.5%-88.1%. Though Pr-Zr solid solution possessed high thermal stability, lattice oxygen was obviously reduced for the recycled sample due to decreased surface oxygen which promoted oxygen vacancies. The increased oxygen vacancies seemed to enhance the oxygen transfer ability in the redox process and provided sufficient oxygen for the methane selective oxidation, resulting in a satisfactory activity. The problem of hot pot was avoided by comparing fresh, aged and recycle sample in the reaction. 展开更多
关键词 METHANE selective oxidation oxygen carrier Pr-Zr solid solution SYNGAS STABILITY
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Application of Fe_2O_3/Al_2O_3 Composite Particles as Oxygen Carrier of Chemical Looping Combustion 被引量:11
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作者 Fang He Hua Wang Yongnian Dai 《Journal of Natural Gas Chemistry》 EI CAS CSCD 2007年第2期155-161,共7页
Chemical looping combustion (CLC) of carbonaceous compounds has been proposed, in the past decade, as an efficient method for CO2 capture without cost of extra energy penalties. The technique involves the use of a m... Chemical looping combustion (CLC) of carbonaceous compounds has been proposed, in the past decade, as an efficient method for CO2 capture without cost of extra energy penalties. The technique involves the use of a metal oxide as an oxygen carrier that transfers oxygen from combustion air to fuels. The combustion is carried out in a two-step process: in the fuel reactor, the fuel is oxidized by a metal oxide, and in the air reactor, the reduced metal is oxidized back to the original phase. The use of iron oxide as an oxygen carrier has been investigated in this article. Particles composed of 80 wt% Fe2O3, together with Al2O3 as binder, have been prepared by impregnation methods. X-ray diffraction (XRD) analysis reveals that Fe2O3 does not interact with the Al2O3 binder after multi-cycles. The reactivity of the oxygen carrier particles has been studied in twenty-cycle reduction-oxidation tests in a thermal gravimetrical analysis (TGA) reactor. The components in the outlet gas have been analyzed. It has been observed that about 85% of CH4 converted to CO2 and H2O during most of the reduction periods. The oxygen carrier has kept quite a high reactivity in the twenty-cycle reactions. In the first twenty reaction cycles, the reaction rates became slightly higher with the number of cyclic reactions increasing, which was confirmed by the scanning electron microscopy (SEM) test results. The SEM analysis revealed that the pore size inside the particle had been enlarged by the thermal stress during the reaction, which was favorable for diffusion of the gaseous reactants into the particles. The experimental results suggested that the Fe2O3/Al2O3 oxygen carrier was a promising candidate for a CLC system. 展开更多
关键词 chemical looping combustion iron oxide oxygen carrier CO2 capture
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New approach for particle size and shape analysis of iron-based oxygen carriers at multiple oxidation states
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作者 Victor Purnomo Marcelo Dal Belo Takehara +2 位作者 Robin Faust Lidiya Abdisa Ejjeta Henrik Leion 《Particuology》 SCIE EI CAS CSCD 2024年第7期493-503,共11页
One of the crucial issues in the chemical looping technology lies in its bed material:the oxygen carrier.Particle size analysis of an oxygen carrier is important since in a fluidized bed the material can only work wel... One of the crucial issues in the chemical looping technology lies in its bed material:the oxygen carrier.Particle size analysis of an oxygen carrier is important since in a fluidized bed the material can only work well within a specific size range.While the favorable size ranges for oxygen carrier materials have already been reported,none of the published studies has analyzed the particle size and shape of oxygen carriers in detail.Furthermore,the effect of oxygen carriers'oxidation degree on such properties has not been considered either.This study aimed to report the particle size and shape analysis of five iron-based oxygen carriers,one natural ore,one synthetic material,and three residue products,at different oxidation degrees using dynamic image analysis(DIA).The oxygen carriers were prepared at different mass conversion degrees in a fluidized bed batch reactor.The size distribution,sphericity,and aspect ratio of the oxygen carrier particles were examined experimentally using a Camsizer instrument.Our results show that the DIA method was successfully able to analyze the particle size and shape of our oxygen carriers with satisfying accuracy for comparison.The oxidation state of the investigated materials seems to only affect the particle size and shape of oxygen carriers to a minor extent.However,exposures to redox cycles in a fluidized bed reactor may alter the particle size and shape of most oxygen carriers. 展开更多
关键词 oxygen carrier Size and shape analysis Dynamic image analysis Oxidation state Fluidized bed Chemical looping
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Comparison of LaFeO_3,La_(0.8)Sr_(0.2)FeO_3,and La_(0.8)Sr_(0.2)Fe_(0.9)CO_(0.1)O_3 perovskite oxides as oxygen carrier for partial oxidation of methane 被引量:4
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作者 Xiaoping Dai Changchun Yu Qiong Wu 《Journal of Natural Gas Chemistry》 EI CAS CSCD 2008年第4期415-418,共4页
Comparison of LaFeO3, La0.8Sr0.2FeO3, and La0.8Sr0.2Fe0.9CO0.1O3 perovskite oxides as oxygen carrier for partial oxidation of methane in the absence of gaseous oxygen was investigated by continuous flow reaction and s... Comparison of LaFeO3, La0.8Sr0.2FeO3, and La0.8Sr0.2Fe0.9CO0.1O3 perovskite oxides as oxygen carrier for partial oxidation of methane in the absence of gaseous oxygen was investigated by continuous flow reaction and sequential redox reaction, Methane was oxidized to syngas with high selectivity by oxygen species of perovskite oxides in the absence of gaseous oxygen. The sequential redox reaction revealed that the structural stability and continuous oxygen supply in redox reaction decreased over La0.8Sr0.2Fe0.9Co0. 1O3 oxide, while LaFeO3 and La0.8Sr0.2FeO3 exhibited excellent structural stability and continuous oxygen supply. 展开更多
关键词 perovskite oxides oxygen carrier METHANE synthesis gas continuous flow reaction sequential redox reaction
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Effect of Gasifying Medium on the Coal Chemical Looping Gasification with CaSO_4 as Oxygen Carrier 被引量:2
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作者 刘永卓 贾伟华 +1 位作者 郭庆杰 Hojung Ryu 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2014年第Z1期1208-1214,共7页
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 ox... 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. 展开更多
关键词 Chemical LOOPING GASIFICATION Ca SO4 oxygen carrier Reaction mechanism SYNGAS generation
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Chemical looping gasification of sewage sludge using copper slag modified by NiO as an oxygen carrier 被引量:3
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作者 Nanhang Dong Ruiqiang Huo +5 位作者 Ming Liu Lisheng Deng Zhengbing Deng Guozhang Chang Zhen Huang Hongyu Huang 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2021年第1期335-343,共9页
Chemical looping gasification(CLG) provides a novel approach to dispose the sewage sludge.In order to improve the reactivity of the calcined copper slag,NiO modification is considered as one of the good solutions.The ... Chemical looping gasification(CLG) provides a novel approach to dispose the sewage sludge.In order to improve the reactivity of the calcined copper slag,NiO modification is considered as one of the good solutions.The copper slag calcined at 1100℃ doped with 20 wt% NiO(Ni20-CS) was used as an oxygen carrier(OC) in sludge CLG in the work.The modification of NiO can evidently enhance the reactivity of copper slag to promote the sludge conversion,especially for sludge char conversion.The carbon conversion and valid gas yield(V_(g)) increase from 67.02% and 0.23 m^(3)·kg^(-1) using the original OC to 78.34% and 0.29 m^(3)·kg^(-1) using the Ni20-CS OC, respectively.The increase of equivalent coefficient(Ω) facilitates the sludge conversion and a suitable Ω value is determined at 0.47 to obtain the highest valid gas yield(0.29 m^(3)·kg^(-1)).A suitable steam content is assigned at 27.22% to obtain the maximum carbon conversion of 87.09%,where an acceptable LHV of 12.63 MJ·m^(-3) and Vg of 0.39 m^(3)·kg^(-1)are obtained.Although the reactivity of Ni20-CS OC gradually decreases with the increase in cycle numbers because of the generation of NiFe_(2) O_(4-δ) species,the deposition of sludge ash containing many metallic elements is beneficial to the sludge conversion.As a result,the carbon conversion shows a slight uptrend with the increase of cycle numbers in sludge CLG.It indicates that the Ni20-CS sample is a good OC for sludge CLG. 展开更多
关键词 Chemical looping gasification(CLG) Copper slag NIO SLUDGE oxygen carrier(OC)
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