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Chemical looping oxidative propane dehydrogenation controlled by oxygen bulk diffusion over FeVO_(4)oxygen carrier pellets

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Chinese Journal of Chemical Engineering 2023年第1期53卷 409-420页

作者： Hongbo Song Wei Wang Jiachen Sun Xianhui Wang Xianhua Zhang Sai Chen Chunlei Pei Zhi-Jian Zhao Key Laboratory for Green Chemical Technology of Ministry of Education School of Chemical Engineering and TechnologyTianjin UniversityTianjin 300072China Collaborative Innovation Center of Chemical Science and Engineering Tianjin 300072China Haihe Laboratory of Sustainable Chemical Transformations Tianjin 300192China Zhejiang Institute of Tianjin University Ningbo 315201China Joint School of National University of Singapore and Tianjin University International Campus of Tianjin UniversityBinhai New CityFuzhou 350207China Department of Chemistry National University of Singapore3 Science Drive 3117543Singapore

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.

关键词： Chemical looping Diffusion Reaction kinetics oxygen carriers Oxidation

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Boosting chemical looping combustion performances of red mud with transition metal oxides

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Carbon Resources Conversion 2022年第2期5卷 119-130页

作者： Jingchong Yan Li Zhang Jing He Muxin Liu Zhiping Lei Zhanku Li Zhicai Wang Shibiao Ren Hengfu Shui School of Chemistry&Chemical Engineering Anhui Province Key Laboratory of Coal Clean Conversion and High Valued UtilizationAnhui University of TechnologyMaanshan 243002China School of Computer Science and Technology Anhui University of TechnologyMaanshan 243002China School of Materials and Chemical Engineering Bengbu UniversityBengbuAnhui Province 233030China

Red mud(RM)is industrial solid waste that severely threatens environmental safety,and its resource utilization is significant both economically and ecologically.The presence of ferric oxides(Fe_(2)O_(3))makes RM potential oxygen carriers(OC)for chemical looping combustion(CLC),which is a promising,novel and low-carbon combustion technology.This work examined the CLC performance of two kinds of RM using gaseous and solid fuels.Both Fe_(2)O_(3) and alkali and alkaline-earth metals(AAEM)species within RM enhance carbon conversion during CLC.Nevertheless,the reactivity of original RM is unsatisfactory due to its low oxygen transporting capacity(R_(0),lower than 0.1),carbon conversion(X_(C),less than 0.8),CO_(2) selectivity(Y_(CO_(2)),less than 0.9)and instable performance.Transition metal oxides including CuO and NiO were used to modify the RM through wet impregnation.Both oxides notably improve RM performances,i.e.,X_(C) and Y_(CO_(2)) are notably increased.Still,deteriorations during redox cycles are observed because of particle agglomeration and sintering,especially for the RM modified with NiO.Considering the cost,potential environmental risk and efficacy,CuO is superior to NiO thanks to the enhanced performances of the modified RM-based OC including higher X_(C)(about 0.9),Y_(CO_(2))(approximately 1)and stronger sintering resistance.

关键词： Red mud Chemical looping combustion oxygen carriers Reactivity Agglomeration

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Efficient hydrogen production through the chemical looping redox cycle of YSZ supported iron oxides

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Green Energy & Environment 2021年第6期6卷 875-883页

作者： Li Ma Yu Qiu Min Li Dongxu Cui Shuai Zhang Dewang Zeng Rui Xiao Key Laboratory of Energy Thermal Conversion and Control of Ministry of Education School of Energy and EnvironmentSoutheast UniversityNanjing210096China

The chemical looping process,where an oxygen carrier is reduced and oxidized in a cyclic manner,offers a promising option for hydrogen production through splitting water because of the much higher water splitting efficiency than solar electrocatalytic and photocatalytic process.A typical oxygen carrier has to comprise a significant amount of inert support,to maintain stability in multiple redox cycles,thereby resulting in a trade-off between the reaction reactivity and stability.Herein,we proposed the use of ion-conductive yttria-stabilized zirconia(YSZ)support Fe_(2)O_(3)to prepare oxygen carriers materials.The obtained Fe_(2)O_(3)/YSZ composites showed high reactivity and stability.Particularly,Fe_(2)O_(3)/YSZ-20(oxygen storage capacity,24.13%)exhibited high hydrogen yield of~10.30 mmol g^(-1) and hydrogen production rate of~0.66 mmol g^(-1) min^(-1) which was twice as high as that of Fe_(2)O_(3)/Al_(2)O_(3).Further,the transient pulse test indicated that active oxygen diffusion was the ratelimiting step during the redox process.The electrochemical impedance spectroscopy(EIS)measurement revealed that the YSZ support addition facilitated oxygen diffusion of materials,which contributed to the improved hydrogen production performance.The support effect obtained in this work provides a potentially efficient route for the modification of oxygen carrier materials.

关键词： Hydrogen production Chemical looping oxygen carriers Support effect

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Preparation and characterization of Ce-Fe-Zr-O(x)/MgO complex oxides for selective oxidation of methane to synthesize gas

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Journal of Rare Earths 2010年第S1期28卷 316-321页

作者：程显名王华魏永刚李孔斋祝星 Faculty of Chemical Engineering Kunming University of Science and Technology Faculty of Metallurgy and Energy Engineering Kunming University of Science and Technology

A series of Ce-Fe-Zr-O(x)/MgO(x denotes the mass fraction of Ce-Fe-Zr-O,x=10%,15%,20%,25%,30%) complex oxide oxygen carriers for selective oxidation of methane to synthesis gas were prepared by the co-precipitation method.The catalysts were characterized by means of X-ray diffraction and H2-TPR.The XRD measurements showed that MgFeO4 particles were formed and Fe2O3 particles well dispersed on the oxygen carriers.The reactions between methane diluted by argon(10% CH4) and oxygen carriers were investigated.Suitable content of CeO2/Fe2O3/ZrO2 mixed oxides could promote the reaction between methane and oxygen carriers.There are mainly two kinds of oxygen of carriers:surface lattice oxygen which had higher activity but lower selectivity,and bulk lattice oxygen which had lower activity but higher selectivity.Among all the catalysts,Ce-Fe-Zr-O(20%)/MgO exhibited the best catalytic performance.The conversion of the methane was above 56%,and the selectivity of the H2 and CO were both above 93%,the ratio of H2/CO was stable and approached to 2 for a long time.

关键词： oxygen carriers lattice oxygen H2/CO selectivity activity rare earths

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Reduction kinetics of bimetallic copper-based oxygen carries for chemical looping combustion

Reduction kinetics of bimetallic copper-based oxygen carries...

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第四届能源转化化学与技术研讨会

作者： Jingchong Yan Xiaogang Chu Zhiping Lei Zhanku Li Zhicai Wang Shibiao Ren Hengfu Shui School of Chemistry & Chemical Engineering Anhui Province Key Laboratory of Coal Clean Conversion and High Valued Utilization Anhui University of Technology

Research and development of cheap but efficient oxygen carriers(OC) are crutial for the implementation of chemical looping technology.In this work,four kinds of copper-based OC, 80 Cu20 Mn,60 Cu40 Co,60 Cu40 Ni and 40 Cu60 Fe,were prepared by the sol-gel method.The reduction reaction characteristics with CO at different temperatures were studied by thermogravimetric,and the reduction reaction mechanism,activation energies and preexponential factors were examined obtained through analysis.During the reduction reaction,the reduction processes of 80 Cu20 Mn and 60 Cu40 Co and CO gas follow the shrinking nucleus model,and the integral function is G(X)=1-(1-x).The reduction of 40 Cu60 Fe proceeds through two steps.The reduction in the first step follows the shrinking geometry(cylindrical symmetry)model with the integral function is G(X)=1-(1-x).The activation energies of 80 Cu20 Mn,60 Cu40 Co and 40 Cu60 Fe are 10.01 kJ/mol, 22.91 kJ/mol and 11.38 kJ/mol,respectively.Due to sintering of the 60 Cu40 Ni,its reaction mechanism varies with the rising temperatures,and they cannot be described by the single and simplied model.

关键词： CLOU CLC oxygen carriers kinetics activation energy

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