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Minimizing carbon deposition in plasma-induced methane coupling with structured hydrogenation catalysts

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Journal of Energy Chemistry 2021年第7期30卷 271-279页

作者： Nuria García-Moncada Toine Cents Gerard van Rooij Leon Lefferts Catalytic Processes and Materials(CPM) TNW FacultyUniversity of TwenteP.O.Box 2177500 AE EnschedeThe Netherlands Sasol Holding Netherlands B.V. 7544 GG EnschedeThe Netherlands nonequilibrium fuel conversion DIFFER5612 AJ EindhovenThe Netherlands

The effect of temperature and hydrogen addition on undesired carbonaceous deposit formation during methane coupling was studied in DBD-plasma catalytic-wall reactors with Pd/Al2 O3, using electrical power to drive the *** with thin catalyst layers allowed comparison of the performance of empty reactors and catalytic wall reactors without significantly influencing the plasma *** product distribution varies strongly in the temperature window between 25 and 200℃Minimal formation of deposits is found at an optimal temperature around 75℃ in the catalytic-wall *** selectivity to deposits was c.a.10% with only 9 mg of catalyst loading instead of 45% in the blank reactor,while decreasing methane conversion only ***-feeding H2 to an empty reactor causes a similar decrease in selectivity to deposits,but in this case methane conversion also decreased *** of deposits formation in the catalytic-wall reactor at 75℃ is due to catalytic hydrogenation of mainly acetylene to *** the empty reactor,H2 co-feed decreases conversion but does not change the product *** catalytic-wall reactors can be regenerated with H2-plasma at room temperature,which produces more added-value hydrocarbons.

关键词： Dielectric barrier discharge(DBD)plasma-catalysis Structured reactor Methane coupling H_(2)co-feed Temperature optimization Carbon deposits

A simple method for determining Hf in Zr and Zr alloys by ICP-AES

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Nuclear Science and Techniques 2009年第6期20卷 340-343页

作者： NABI Mehdi SHAHBAZI Pouyan fuel Manufacturing Plan (FMP) Isfahan Iran Uranium conversion Facilities (UCF) Isfahan Iran

This paper describes a rapid, accurate and precise method for determination of trace hafnium (Hf) in zirconium and zirconium alloys by inductively coupled plasma atomic emission spectrometry (ICP-AES). It was found that using a mixture of sulfuric acid (H2SO4) and ammonium sulfate (NH4)2SO4, the total sample dissolution time was 15 min. Experimental works revealed that a high Zr concentration would result in a significant decrease in the peak height of the analyte lines, which was corrected by standard addition method. The performance of the developed method was evaluated by calculating the recovery percent and using standard reference material analysis. The recoveries were in the range of 97.6%-99.5% and the relative standard deviations were within 0.8%-3.0%. The detection limit (3σ) of Hf was found to be 0.01 μg·g-1, respectively. The proposed technique, with high precision and accuracy, was applied to the analysis of trace Hf in zirconium-niobium ingots and tubes for the first time in Iran.

关键词：锆合金 ICP AES 电感耦合等离子体原子发射光谱法测定铪 H2SO4 标准加入法

Study on the growth of platinum nanowires as cathode catalysts in proton exchange membrane fuel cells

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Frontiers of Chemical Science and Engineering 2022年第3期16卷 364-375页

作者： Ruiqing Wang Xiaolan Cao Sheng Sui Bing Li Qingfeng Li Institute of fuel Cells Shanghai Jiao Tong UniversityShanghai200240China School of Mechanical and Power Engineering East China University of Science and TechnologyShanghai200237China Department of Energy conversion and Storage Technical University of Denmark2800LyngbyCopenhagenDenmark

The platinum nanowires have been verified to be a promising catalyst to promote the performance of proton exchange membrane fuel *** this paper,accurately controlled growth of nanowires in a carbon matrix is achieved for reducing Pt *** effects of formic acid concentration and reaction temperature on the morphology and size of the Pt nanowires,as well as their electrochemical performances in a single cell,are *** results showed that the increase in the formic acid concentration results in a volcano trend with the length of Pt *** increasing reduction temperature,the diameter of Pt nanowires increases while Pt particles evolve from one-dimensional to zero-dimensional up to 40°C.A mechanism of the Pt nanowires growth is *** optimized Pt nanowires electrode exhibits a power density(based on electrochemical active surface area)79%higher than conventional Pt/C *** control strategy obtained contributes to the design and control of novel nanostructures in nano-synthesis and catalyst applications.

关键词： Pt nanowires morphology structure control in situ growth mechanism proton exchange membrane fuel cells

Recent progress in the structure optimization and development of proton-conducting electrolyte materials for low-temperature solid oxide cells

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International Journal of Minerals,Metallurgy and Materials 2022年第4期29卷 848-869页

作者： Jia Song Yuvraj Y.Birdja Deepak Pant Zhiyuan Chen Jan Vaes Separation and conversion Technology Flemish Institute for Technological Research(VITO)Mol 2400Belgium

This work reviews technologies that can be used to develop low-temperature solid oxide cells(LT-SOCs)and can be applied in fuel cells and electrolyzers operating at temperatures below 500℃,thus providing a more cost-effective alternative than conventional high-temperature *** routes showing potential to reduce the operating temperature of SOCs to below 500℃ are *** first route is the principal way to enhance cell performance,namely,structure *** technique includes the reduction of electrolyte thickness to the nanometer scale and the exploration of electrode structure with low polarization *** other route is the development of novel protonconducting electrolyte materials,which is in the frontier of SOCs *** fundamentals of proton conduction and the design principles of commonly used electrolyte materials are briefly *** most widely studied electrolyte materials for LT-SOCs,namely,perovskitetype BaCeO_(3) -and BaZrO_(3) -based oxides,and the effect of doping on the physical-chemical properties of these oxide materials are summarized.

关键词： low-temperature solid oxide cells perovskite doping thin-film

The study of methanol aromatization on transition metal modified ZSM-5 catalyst

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Chinese Journal of Chemical Engineering 2018年第9期26卷 1949-1953页

作者： Keming Ji Jiayao Xun Ping Liu Qingwen Song Junhua Gao Kan Zhang Jingyuan Li State Key Laboratory of Coal conversion Institute of Coal Chemistry Chinese Academy of Sciences

In this article, transition metals of Cu, La and Zn were used as adjuvant to prepare modified HZSM-5 by impregnation method. The catalysts were characterized by XRD, BET, NH_3-TPD and Py-IR to reveal the microstructure and acid property. The catalysis performances of methanol aromatization of catalysts were investigated in a fixed-bed reactor. The results show that the strength and distribution of acid center of these catalysts are significantly influenced by the species of transition metal. There are more mediate strong Lewis acid center in Zn modified HZSM-5 catalyst and therefore exhibits higher selectivity to aromatic, benzene, toluene and xylenes in the MTA reaction..

关键词： Aromatization ZSM-5 Metal modified

Effect of baffles on bubble behavior in a bubbling fluidized bed for chemical looping processes

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Particuology 2020年第6期18卷 154-167页

作者： Xiao Zhu Xuan Feng Yuanyuan Zou Laihong Shen Key Laboratory of Energy Thermal conversion and Control of Ministry of Education Southeast UniversityNanjing 210096China

A bubbling fluidized bed is generally used as the fuel reactor in chemical looping ***,in sufficient gas-solid contact remains a steadfast *** such,we propose the use of in ternal baffles to split bubbles at a high gas velocity and to restrict the movement of large-scale solids in the fluidized *** investigated the effect of baffle arrangement on the bubble size and energy,pressure gradient,particle distribution,and particle velocity in a fluidized bed using a computational particle fluid dynamics simulation based on our experimental *** discuss the main influenci ng factors,which in elude presence of caps,number of baffles,and the baffle opening *** baffle structure with caps efficiently broke the large bubbles without creating jet *** baffles were deemed suitable in the bed owing to the small bubble size and uniform gas-solid distribution in each *** selected a baffle opening ratio of 20.5%,which improved the flow pattern without causing a significant increase in the pressure gradient and particle velocity through the *** also discussed the potential for sea ling up this baffled fluidized bed for industrial applications.

关键词： Baffle Bubble behavior Fluidized bed Chemical looping CPFD simulations

Study on the emission characteristics of nitrogen oxides with coal combustion in pressurized fluidized bed

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Chinese Journal of Chemical Engineering 2019年第5期27卷 1177-1183页

作者： Zheng Gong Yingjuan Shao Lei Pang Wenqi Zhong Chao Chen Key Laboratory of Energy Thermal conversion and Control of Ministry of Education School of Energy and Environment Southeast University

Nitrogen oxides are one of the most significant pollution sources during coal combustion. This experimental study was conducted in a 15 kWth lab-scale pressurized fluidized bed (inner diameter = 81-100 mm, H = 2100 mm) firing with bituminous coals. The effects of operating parameters, including bed temperature (800℃-900℃), operating pressure (0.1-0.4 MPa), excess air level (16%-30%) and flow pattern on NOX and N2O emissions were systematically studied during the tests. During each test the interaction effects of all the operating parameters were properly controlled. The results show that most operating parameters have an opposite effect on NOX and N2O emissions, and the N2O emissions mainly depend on the bed temperature. Increasing the operating pressure can significantly suppress the fuel-N conversion to NOX but enhance its conversion to N2O. With the rise of the excess air level and fluidization number, NOX emissions grow distinctly while N2O emissions remain almost unchanged. Total nitrogen oxide emissions increase with the bed temperature while decrease with the operating pressure.

关键词： Pressurized fluidized bed coal combustion Operating parameter NOX N2O

Chemical-looping gasification of biomass in a 10 kW_(th) interconnected fluidized bed reactor using Fe_2O_3/Al_2O_3 oxygen carrier

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燃料化学学报 2014年第8期42卷 922-931页

作者： HUSEYIN Sozen WEI Guo-qiang LI Hai-bin HE Fang HUANG Zhen CAS Key Laboratory of Renewable Energy Guangzhou Institute of Energy ConversionChinese Academy of Sciences (CAS)

Abstract:The aim of this research is to design and operate a 10 kW hot chemical-looping gasification(CLG)unit using Fe2O3/Al2O3as an oxygen carrier and saw dust as a *** effect of the operation temperature on gas composition in the air reactor and the fuel reactor,and the carbon conversion of biomass to CO2and CO in the fuel reactor have been experimentally studied.A total60 h run has been obtained with the same batch of oxygen carrier of iron oxide supported with *** results show that CO and H2concentrations are increased with increasing temperature in the fuel *** is also found that with increasing fuel reactor temperature,both the amount of residual char in the fuel reactor and CO2concentration of the exit gas from the air reactor are *** conversion rate and gasification efficiency are increased by increasing temperature and H2production at 870℃reaches the highest *** electron microscopy(SEM),X-ray diffraction(XRD)and BET-surface area tests have been used to characterize fresh and reacted oxygen carrier *** results display that the oxygen carrier activity is not declined and the specific surface area of the oxygen carrier particles is not decreased significantly.

关键词： chemical-looping gasification hot model biomass Fe2O3/Al2O3 dual circulating fluidized bed

Synthesis, characterization and electrocatalytic studies of palladium–manganese oxyhydroxide nanocomposite towards direct ethylene glycol fuel cell

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Chinese Science Bulletin 2014年第27期59卷 3413-3419页

作者： Ramanujam Kannan Ae Rhan Kim Dong Jin Yoo R&D Education Center for Specialized Graduate School of Hydrogen and fuel Cells Engineering Chonbuk National University Chonju Joellabuk-do 561-756 Korea Department of Energy Storage/conversion Engineering Hydrogen and Fuel Cell Research Center Graduate SchoolChonbuk National University Chonju Joellabuk-do 561-756Korea Department of Chemistry Chonbuk National UniversityChonju Joellabuk-do 561-756 Korea

The palladium nanoparticle grafted manganese oxyhydroxide nanorod(MON) electrocatalyst has been synthesized and tested for the electrooxidation of ethylene glycol(EG) in an alkaline medium. The MON was prepared using the hydrothermal method and the Pd nanoparticles were coated on the MON using an in situ reduction method. The nanocatalyst thus prepared was characterized by powder X-ray diffraction, scanning electron microscopy, high resolution transmission electron microscopy, energy dispersive X-ray spectroscopy and electrochemical methods. The microscopic studies confirm the formation of MON and reveal that the Pd nanoparticles were grafted uniformly on the MON. In the voltammetric studies, the Pd/MON catalyst exhibited a six-fold improved peak current for ethylene glycol electrooxidation compared with the C/Pd. The EG electrooxidation reaction performances of the Pd/MON nanocatalyst in the alkaline solutions containing different quantities of EG were tested through cyclic voltammetry. The catalytic removal of the poisonous intermediates formed during electrooxidation of EG was explained. The present study shows that MON can act as an active support for the Pd nanocatalyst.

关键词：钯纳米粒子氢氧化锰乙二醇化学研究燃料电池纳米复合合成高分辨透射电子显微镜