Numerical simulation of coupled thermo-electrical field for 20 kA new rare earth reduction cell

To solve the problems of high energy consumption,low efficiency and short service life of conventional rare earth reduction cells,a 20 kA new rare earth reduction cell(NRERC)was presented.The effects of the anode-cathode distance(ACD)and electrolyte height(EH)on the thermo-electrical behavior of the NRERC were studied by ANSYS.The results illustrate that the cell voltage drop(CVD)and the temperature will rise with a similar tendency when the ACD increases.Also,the temperature rises gradually with EH,but the CVD decreases.Ultimately,when the ACD is 115 mm and the EH is 380 mm,the CVD is 4.61 V and the temperature is 1109.8℃.Under these conditions,the thermal field distribution is more reasonable and the CVD is lower,which is beneficial to the long service life and low energy consumption of the NRERC.

Low Temperature Preparation of Ceria Solid Solutions Doubly Doped with Rare-Earth and Alkali-Earth and Their Properties as Solid Oxide Fuel Cells

A series of solid electrolytes, (Ce 0.8 Ln 0.2 ) 1- x M x O 2-δ (Ln= La, Nd, Sm, Gd, M:Alkali earth), were prepared by amorphous citrate gel method. XRD patterns indicate that a pure fluorite phase is formed at 800 ℃. The electrical conductivity and the AC impedance spectra were measured. XPS spectra show that the oxygen vacancies increase owing to the MO doping, which results in the increase of the oxygen ionic transport number and conductivity. The performance of ceria based solid electrolyte is improved. The effects of rare earth and alkali earth ions on the electricity were discussed. The open circuit voltages and maximum power density of planar solid oxide fuel cell using (Ce 0.8 Sm 0.2 ) 1-0.05 Ca 0.05 O 2- δ as electrolyte are 0.86 V and 33 mW·cm -2 , respectively.

Study of Bi_2O_3-based Rare Earth Solid Electrolyte Used in Fuel Cell

Solid ceramic electrolyte materials (Bi_2O_3)_(0.75)(Y_2O_3)_(0.25) and(Bi_2O_3)_(0.65)(Gd_2O_3 )_(0.35)were synthesized.Their crystal structure, XPS spectra and the change of ionic conductivity versus temperature were measured.A Bi_2O_3-based rare earth solid electrolyte fuel cell with ZrO_2-Y_2O_3 protection film was made.

Simulation of Flow Field of Molten Salt in Neodymium Metal Electrolytic Cell Using Vortex-Flow Function Method

With the applications of Nd-Fe-B material extending in recent years, the materials of neodymium metal and other rare earth metal alloy confront the increased demand and the high quality request at the same time.These factors stimulated greatly to perfect the producing craft of RE metals and improve the equipments.The rare earth electrolysis cell is developing towards large-scale way.Notwithstanding the present electrolysis cell of Nd metal, include 6 kA and 10 kA cell, exists some insurmountable problems during operation and these problems lead to lower electric efficiency and higher operating costs.So it is significant to study the physical fields of rare earth electrolysis cell.In this paper,a numerical flow mode is established using vortex- flowing function method and the fluid flow field of 3000A Nd electrolysis cell is computed using MATLAB.The results of the study will be important reference in theory for improving and enlarging rare earth fluoride system cell.

Effect of samarium doped ceria nanoparticles impregnation on the performance of anode supported SOFC with(Pr_(0.7)Ca_(0.3))_(0.9)MnO_(3-δ) cathode

Solid oxide fuel cell(SOFC) electrodes,after a high temperature sintering,may be impregnated to deposit nanoparticles within their pores to enhance the catalytic function.Samarium doped CeO2(SDC) nanoparticles were infiltrated into(Pr0.7Ca0.3)0.9MnO3-δ(PCM) cathode of anode supported SOFC cells.The cell with 2.6 mg/cm2 SDC impregnated in cathode showed the maximum power density of 580 mW/cm2 compared with 310 mW/cm2 of the cell without impregnation at 850 °C.The cells were also characterized with the impeda...

Preparation and Characterization of La_(0.8)Sr_(0.2)MnO_(3-δ) Cathode for SOFCs Fabricated Using Azeotropic Distillation Method

Strontium doped lanthanum manganite (LSM) powders were synthesized by three different routes: azeotropie distillation, sol-gel and solid state reaction respectively. The LSM samples, made by azeotropic distillation and sol-gel methods were prepared by firing at 1000℃for 6 h, and the LSM sample, made by solid state reaction method was produced by sintering at 1400℃for 18 h. The samples were characterized by XRD, TEC, SEM, EIS and polarization performance analysis. The results show that all the samples made by different methods have pure orthorhombic LSM phase, however exhibit different micro structure and electrochemical characterization, which relates to the different synthesis methods. The solid state reaction method produces the samples with larger particle size compared with azeotropic distillation and sol-gel methods. The powders made by azeotropic distillation method have less agglomerated particles compared with that made by sol-gel method because the precursor in the former is dispersed in n-butanol before sintering. The polarization current density of powder made by azeotropic distillation method was twice of that made by sol-gel method and four times of that made by solid state reaction method. The values of polarization resistance (Rp) are 0.35Ω·cm for the cathode synthesized by azeotropic distillation route, which is much lower than sol-gel (1.5Ω·cm2) and solid state reaction (2.3Ω·cm2) at 800℃.

Synthesis and Electrical Properties of La_(0.6)M_(0.4)FeO_(3-δ)(M=Ca, Sr, Ba) as Cathodes for SOFCs

A series samples of La0.6M0.4FeO3-δ （M = Ca, Sr, process （GNP）. FTIR, TG-DSC, XRD and TEM techniques Ba） perovskite-type oxides were prepared by glycine nitrate were used to characterize the chemical constitution, thermal stability and phase structure. The electrical conductivity of the samples was investigated by four-probe technique. With the increase of substituted-ionic radius, the temperature of phase formation increases, and the solid solubility decreases gradually, respectively. The La0.6Ca0.4FeO3-δ（LCF）powder is pure cubic perovskite-type crystalline after fired at 850℃ for 2 h. The XRD patterns of La0.6Sr0.4FeO3-δ（LSF） powder shows a small quantity of SrO peaks sintered at 1050℃ for 2 h. The electrical conductivity of LCF and LSF at 500 - 800℃ is over 100 S·cm^ - 1, and the value of LCF is 1170 S·cm^ - 1 at 800℃, which indicate that LCF and LSF may be used as a profitable cathode for IT-SOFCs. The characteristic of La0.6 Ba0.4FeO3-δ（LBF） is poor, and the electrical conductivity at intermediate temperatures is 1/20 less than that of LSF.

Electrical Properties of La_(0.8)Sr_(0.2)Co_(1-y)Fe_yO_(3-δ) for SOFC Cathodes

La0.8Sr0.2Co1-yFeyO3-δ (y=0.2, 0.4, 0.6, 0.8) powders were synthesized by ethylenediamine tetraacetic acid (EDTA) complexing sol-gel process. The powders were characterized via X-ray diffraction (XRD) and scanning electron microscope and energy dispersive X-ray spectroscopy (SEM-EDS). The results showed that single-phased perovskite-type oxide powders with small particle size were obtained by the process, and the compositions of the productions agreed with the designed molar ratio. The electronic conductivity and ionic conductivity of La0.8Sr0.2Co1-yFeyO3-δ were investigated by DC four-terminal method and AC impedance spectroscopy, respectively. The electronic conductivity of La0.8Sr0.2Co1-yFeyO3-δ is approximately 2～4 orders of magnitude higher than the ionic conductivity. It was confirmed that the conductivities of the materials were strongly influenced by the composition anions, temperature and sample preparing process.

通电方式对稀土熔盐电解影响的数值模拟及分析

在稀土熔盐的电解过程中,不同的通电方式对槽内各物理场影响也不同,进而会对电解槽的电解效率产生一定的影响。本文以某企业8 kA稀土电解槽为原型,通过Comsol的热电耦合模块研究通电铜板单侧与多侧分布的通电方式及通电铜板的不同位置分布下的电解槽电解时内部各物理场的变化情况,通过对比电流密度、电势差、电解温度的大小寻找最合适的通电方式。结果表明:只考虑电解效率时,导电板四侧中位通电最优分布方式,此时电解槽内电流密度最大,电能损耗最低,电解效果最好。若考虑制造成本以及可操作性,导电板单侧中位分布是最优解,这种设计的电解槽电解效率较高,同时也留出较大操作空间。其余几种分布均存在弊端,需要进一步完善。该研究旨在为稀土电解槽的结构优化提供参考意见。

稀土金属制备用石墨阳极特性分析

为探究影响稀土金属制备用石墨阳极使用寿命的主要因素,采用数码显微镜、光学显微镜、扫描电子显微镜、X射线衍射仪、同步热分析仪、四探针测试仪对不同使用寿命石墨阳极的宏观和微观形貌、晶体结构、石墨化度、热学性能、电阻率进行了比较和综合评估。结果表明,石墨阳极电阻率、内部裂纹及孔隙度是造成石墨阳极使用寿命差异的主要因素。研究结果可为稀土金属制备用石墨阳极的筛选提供参考,为企业降本增效提供技术支持。

稀土电解槽数值模拟研究现状及发展趋势

稀土电解槽是熔盐电解法制备稀土金属的核心设备,优化槽型结构对制备稀土的电解工艺向着高效化、大型化方向发展具有重要意义。为了全面深入了解现有稀土电解槽流场、电场、温度场等研究现状,从上插式稀土电解槽流场、上插式稀土电解槽电热耦合场、大型稀土电解槽和底部阴极式稀土电解槽的仿真现状四个方面进行概述。总结基于数值模拟方法对稀土电解槽开发设计及结构优化,提出仍需改进或补充的仿真工作,并展望稀土电解槽未来的发展方向。

Applications and recent advances of rare earth in solid oxide fuel cells

Solid oxide fuel cells(SOFCs)are an all-solid energy conversion device from the chemical energy of fuels to electric energy at intermediate and high temperatures.Up to now,massive efforts have been made in developing different components of solid oxide fuel cells,including electrolyte,anode,cathode and interconnect materials.Rare earth elements play an indispensable role in different components of SOFCs which have been extensively studied in the recent decades.In this review,we concentrate upon the rare earth application and recent advances in SOFCs and related materials.Materials structure involves perovskites,Ruddlesden-Popper,fluorite,spinel,pyrochlore,apatite and so on.Moreover,the effects of rare earth based oxides as matrix or dopants in different components are also discussed.Structures and properties of the materials are related to the element type,valence,coordination and ion radius.This article will provide a comprehensive research direction towards SOFCs components for their composition,structural design and mechanisms research.

10kA底部阴极稀土熔盐电解槽热平衡计算

对10kA底部阴极结构稀土熔盐电解槽进行了热平衡计算,并对计算结果进行了分析和讨论,为槽型的改进和电解过程的节能降耗提供合理有效的建议。

全封闭底部液态阴极结构稀土电解槽的模拟与设计

利用ANSYS10.0软件对20kA底部液态阴极结构的电解槽进行温度场、电场的模拟计算,并结合计算结果设计出一种极距为10cm、半径为92cm的20kA全封闭底部液态阴极结构电解槽。该电解槽采用阳极切分方式来减轻阳极质量,且不会对电解槽的电场造成影响,同时设计钢爪+石墨的阳极固定方式,以降低阳极残极消耗。槽盖的设计可提高电解槽的电流效率,降低能耗;N2进气口的设计可防止石墨阳极侧面被氧化消耗。

6kA方型稀土电解槽电场的研究

研究了阴极阳极变化对于6 kA方型稀土电解槽电场的影响,并在此基础上分析阴极半径的范围,为电解槽设计改造提供了参考依据。

复合电解质材料的电性能及应用

利用固相法制备了不同粒度的Ce0.8Sm0.2O1.9(SDC)与(ZrO2)0.92(Y2O3)0.08(YSZ)的复合材料(SDC与YSZ的质量比分别为1∶9,3∶7,5∶5),以其为电解质制备成片状燃料电池,X射线衍射结果表明,材料呈双相复合结构,阻抗谱和电池性能的测量结果表明,电解质在低温和掺杂量较低时电导率比纯YSZ高,在电池工作温区(700～850℃)内电导率都较低.以它为电解质的氢氧燃料电池开路电压很低,并且随SDC掺杂量的升高下降的非常明显.

8kA稀土电解槽阴极对电场影响的数值模拟

针对电解过程中稀土电解槽的电能消耗大以及电极腐蚀严重等问题,利用商业软件ANSYS对8kA稀土电解槽不同阴极直径和和不同插入坩埚内的深度的电场进行数值模拟,发现当阴极直径增大时电解槽内收集器附近电压随之降低而阴极表面的电流密度随之增大,随着阴极插入坩埚深度的增加阴极表面的电流密度分布更加均匀,结合实际生产经验,阴极直径控制在70mm左右阴极插入深度控制在410mm左右对降低电能消耗提高生产效率最为有利。根据研究结论能够帮助确定8kA稀土电解槽合理的阴极直径尺寸和位置,为该型电解槽结构优化提供参考依据。

氟氧化钕耐火材料的研制与应用

为给大型稀土金属电解槽提供一种抗氟盐侵蚀和高温抗氧化性好 ,且对稀土金属产品无污染的内衬材料 ,以氧化钕、氟化钕及钕电解槽炉底的结瘤物为主要原料 ,将氧化钕和氟化钕或炉底料按一定比例混合、压制成块和烧成来制备熟料 ,再将熟料破粉碎 ,配料成型 ,最后烧成 ,制备了以氟氧化钕为主要组成的新型耐火材料。通过实际应用表明 ,该材料具有一定的抗氟盐侵蚀能力和高温下的抗氧化能力 ,应用于大型稀土氟化物熔盐电解槽 。

稀土熔盐电解槽电场的仿真模拟

利用有限元软件ANSYS具有的多重单元、多重属性的特点,建立了稀土电解槽的电极及熔体整体电场数学模型。对电解槽的电极插入不同深度及不同极间距的电场进行了仿真模拟,得出了槽电压及电位分布与电极插入不同深度及不同极间距的关系。

不同阴阳极圆心距下稀土电解槽的电解特性分析

为了研究稀土熔盐电解槽的电解效率与温度场分布的关系,以15kA大电流稀土电解槽为研究对象,利用COMSOL多物理场耦合软件,计算了不同的阴阳极圆心距的稀土电解槽的温度场分布和电场等参数.得出了电解槽温度场分布随阴阳极圆心距位置变化关系图,并分析了电解槽内温度场分布对整个电解反应过程的影响,为电解槽的结构优化和安装提供了参考依据.