熔融碳酸盐燃料电池的研究和发展

本文广泛地总结了熔融碳酸盐燃料电池在世界范围内所取得的进展：阐明了电池的工作原理和电池结构上最新发展，最终强调了进一步研究的一些问题。     

三聚氰胺工艺中熔盐的再生及更换

提出2种熔盐再生方案,采用1种特殊方法将高温熔盐从储槽中取出,实现了熔盐的安全更换。     

熔盐电解法渗硼工艺的优化

采用熔盐脉冲电解法对20钢进行渗硼实验,利用正交试验考察了电流密度、占空比、渗硼温度、时间及硼砂物质的量等因素对渗硼层厚度的影响。结果表明,各因素对20钢渗硼层厚度影响的主次顺序为,渗硼温度电流密度硼砂物质的量占空比渗硼时间。最优工艺参数电流密度为12 A/dm2、占空比20%、渗硼θ为850℃、t为90 min、熔盐摩尔配比n(Na Cl)∶n(KCl)∶n(Na F)∶n(Na2B4O7)=1∶1∶3∶0.04。按最优工艺进行电解渗硼,得到的渗层较厚,渗层组织较细致紧密。     

Studies on the Development of a Flow-Sheet for AHWR Spent Fuel Reprocessing Using TBP

The present paper describes the results of solvent extraction studies carried out in batch mode to collect data on distribution of uranium, plutonium, and thorium using 5% TBP in n-dodecane. Extraction studies are carried out from feed solutions having bulk thorium containing aluminum and fluoride ions in ～3.00–4.00 M nitric acid at concentration levels anticipated in feed solutions during Advanced Heavy Water Reactor (AHWR) spent fuel reprocessing. Studies are carried out under varied experimental conditions. Parameters such as organic to aqueous phase ratio during extraction, concentration of nitric acid for scrubbing co-extracted thorium from loaded organic phase etc., are studied in detail. Hydroxylamine nitrate is selected for reductive stripping of plutonium in preliminary studies. Reagent mixture containing 0.30 M HAN + 0.60 M HNO₃ and 0.20 M N₂H₄ is found to be optimum for plutonium partitioning. This paper also describes the extraction and stripping of uranium and plutonium in co-current mode. The extraction behavior of relevant fission products is studied from a simulated feed solution. A preliminary study on a few commercially available reducing agents is also included. These data are useful in developing a flow-scheme for the recovery of uranium and plutonium from spent fuel originating from AHWR.     

MCFC动态性能数值模拟

A three dimension of dynamic mathematical model of the molten carbonate fuel cell is established,in which the heat generation, mass transfer and electrochemical characteristics are described. The performance of the fuel cell including the distributions of the temperature and the velocity is predicted numerically. Then the experimental data including the output performance of the fuel cell generation system and the temperature distributions are compared. The numerical results are in agreement with the experiment results.     

Experimental studies and model validation for the optimization of electrodes configuration in a molten salt electrorefiner

Molten salt electrorefining is a high-temperature electrochemical process for treating the spent metallic fuel from fast reactors and is aimed at the separation of U and Pu from fission products. Potential and current distribution analysis was carried out by experimental studies as well as modelling using COMSOL Multiphysics for various electrode configurations. A 2D/2D axisymmetric geometry model was used to evaluate the potential and current distributions. The effect of the following parameters was evaluated: (1) configuration having two pairs of electrodes in parallel/staggered arrangement; (2) centre-to-centre distance between the electrodes; (3) solid cathode with and without insulation at the bottom; (4) Cd cathode and (5) cathode surface area. The resistance of the electrorefiner was calculated using COMSOL model for various electrode configurations and compared with that obtained experimentally. There was very good agreement between the experimental values and the simulation results. The computed cell resistance was also validated with published data. A sensitivity analysis was also performed to determine the parameter that more significantly influences the cell resistance. The two parameters that were varied were the electrolyte conductivity and the cell voltage. It is observed that of the two parameters the cell resistance is most sensitive to the electrolyte conductivity and there is no change in cell resistance with cell voltage.     

Na2CO3-K2CO3熔盐法同时制取合成气和金属锌

针对传统的甲烷转化制合成气及金属锌制备技术的缺陷,提出了一种新型的熔融盐反应体系,在熔融盐反应器中以熔融盐(质量比为1:1的Na2CO3/K2CO3)为反应介质对CH4与ZnO反应同时生成金属锌和合成气作了实验研究,利用气相色谱对气体组分进行了分析. 结果表明,反应尾气组分主要是H2, CO和CH4,未检测到CO2,其中合成气的量及H2/CO比例随反应温度的升高而增加,在1198 K左右获得了H2/CO比为2的合成气. 合成气和金属锌分别从气相和熔融盐中获得. 用XRD, SEM及EDS对金属锌产品和熔融盐进行了表征,发现反应后的熔融盐含有少量Na2O和NaOH,来自于CH4与熔融盐之间的微弱反应,由此推断熔融盐还具有消碳功能.     

Electrolytic Reduction of Spent Nuclear Oxide Fuel as Part of an Integral Process to Separate and Recover Actinides from Fission Products

Abstract

Bench‐scale tests were performed to study an electrolytic reduction process that converts metal oxides in spent nuclear fuel to metal. Crushed spent oxide fuel was loaded into a permeable stainless steel basket and submerged in a molten salt electrolyte of LiCl–1 wt% Li₂O at 650°C. An electrical current was passed through the fuel basket and a submerged platinum wire, effecting the reduction of metal oxides in the fuel and the formation of oxygen gas on the platinum wire surface. Salt and fuel samples were analyzed, and the extent of fission product separation and metal oxide reduction was determined.     

The Possibility of Reprocessing of Spent Nuclear Fuel Using Supercritical Fluids

For the first time, the possibility of dissolution of spent nuclear fuel from a nuclear power plant in liquid and supercritical carbon dioxide was demonstrated. As shown by the example of spent nuclear fuel, the dissolution and the extraction of actinides and fission products by solutions of tributyl phosphate and nitric acid adducts TBP(HNO₃)_1.8 in carbon dioxide can be used as one of the stages of spent nuclear fuel reprocessing.     

熔融盐膜法脱除航天舱中CO2传质模型

基于电化学理论、膜分离与传质理论，采用非平衡态热力学，建立了熔融盐(43．5％ Li2CO2 25％K2CO3 31.5?Na2CO3)(mol.?膜法脱除C02数学模型。首先，根据熔盐体系离子的Hittorf迁移数、比电导、扩散系数等独立实验参数，计算得到体系的Onsager系数和模型参数，然后用计算机求得该模型的数值解。解的结果表明：影响CO2传质通量的因素主要有电流密度及C02在膜两侧的浓度差。在低电流密度下，浓差推动力起主导作用：在较高电流密度下，膜两侧浓差推动力对C02传质影响甚微，电流密度对C02的传质则起着决定性作用。为了进一步验证数学模型，在823K及常压条件下，模拟航天舱中的气体成分，进行了熔融盐膜法脱除CO2的实验研究。实验结果与模型理论解吻合较好。     

Selective Separation of Cs and Sr from LiCl-Based Salt for Electrochemical Processing of Oxide Spent Nuclear Fuel

Abstract

Electrochemical processing technology is currently being used for the treatment of metallic spent fuel from the Experimental Breeder Reactor-II at Idaho National Laboratory. The treatment of oxide-based spent nuclear fuel via electrochemical processing is possible provided there is a front-end oxide reduction step. During this reduction process, certain fission products, including Cs and Sr, partition into the salt phase and form chlorides. Both solid state and molten LiCl-zeolite-A ion exchange tests were conducted for selectively removing Cs and Sr from LiCl-based salt. The solid-state tests produced in excess of 99% removal of Cs and Sr. The molten state tests failed due to phase transformation of the zeolite structure when in contact with the molten LiCl salt.     

离子交换法制硫卤玻璃光波导用铯熔盐的研究

研究了自合成的单元 Cs Ac,二元 Cs Ac- Cs NO3 和三元 Cs Ac- Cs NO3 - KAc系统的熔点及凝固点的变化趋势 ,并初步进行了模拟离子交换的实验。实验结果表明 ,二元及三元系统的熔点较单元系统可下降 30℃和 40℃ ,最低可达 1 45℃ ,而凝固点则降至 1 2 6℃ ,满足硫卤玻璃进行离子交换时对熔盐熔点的特殊要求。     

Computer Modeling System of the Industrial Diesel Fuel Catalytic Dewaxing Process

An unsteady mathematical model and a computer modeling system of the diesel fuel catalytic dewaxing process (mild hydrocracking) were developed. The modeling system allows for calculating the optimal technological mode to produce low‐freezing diesel fuel with the required cold filter plugging point taking into account the feedstock composition and catalyst activity. The modeling system consists of the main blocks: database, knowledge base, unsteady mathematical model of the diesel fuel catalytic dewaxing process, and application program package. Using the developed computer modeling system, the influence of the feedstock composition and flow rate as well as of the catalyst activity on the cold filter plugging point and the yield of diesel fuel is demonstrated.     

水冲压发动机用金属燃料的研究进展

介绍了用于超高速鱼雷的巡航动力推进系统——水冲压发动机的基本原理,阐述了水反应金属燃料的组成及特点,以金属镁与水在不同状态下的反应机理为例对水反应金属燃料的工作原理进行了分析。并提出燃料的组织形式、点火技术和燃烧性能调节技术等是水反应金属燃料研究中的关键技术。通过总结国内外水冲压发动机及水反应金属燃料的研究进展,指出国内相关领域研究的不足和发展方向。附参考文献22篇。     

苯丙酮酸钠反应结晶过程的数学模拟

建立了苯丙酮酸钠反应结晶过程的数学模型,研究了在苯丙酮酸醚萃取液中滴加稀碱溶液的反应结晶过程;对该过程涉及的湍流扩散宏观返混及界面化学反应进行分析,提出了一种简化、有效的混合模型;并考虑了结晶的团聚和破碎作用;运用离散化的粒数平衡方程可求解得到ＣＳＤ（晶体粒度分布）。该模型得到了实验数据的支持,为进一步的过程优化提供了依据。     

硫磷双辛基碱性锌盐生产工艺的改进

选用氨水溶液代替醋酸作为新型催化剂用于硫磷双辛基碱性锌盐(T203)的皂化反应。在其它反应条件不变的情况下,反应产物的过滤速度提高约1倍,并且产品的其它性能指标仍能达到有关的标准和产品规格要求。     

铁水连续预处理涡流反应器内液固两相流动特征的数值模拟

铁水预处理技术中反应器的设计至关重要. 采用k-e湍流模型与颗粒随机轨道模型相结合的两相流动模型,数值模拟了涡流反应器内铁水、反应剂的两相流动特征. 计算结果表明,选取本研究所用的反应器几何参数和运行参数,反应剂颗粒能有效地加入铁水中,与铁水较好混合,可达到设想的加料、混合、进而进行化学反应的效果.     

常温下以甲烷为燃料的质子交换膜燃料电池发电可行性研究

尝试了常温下以甲烷为燃料的质子交换膜燃料电池发电的可能性，研究了温度和阳极催化剂对其燃料电池开路电压和放电性能的影响。结果表明，甲烷在常温下能够进行电化学氧化，随着电池工作温度的升高，燃料电池的开路电压和功率密度逐渐增加。阳极催化剂的铂含量和催化剂的组成对甲烷的电化学氧化具有非常大的影响。90℃下使用Pt（40wt．％）-Ru（20wt．％）／C为阳极催化剂（催化剂担载量：（2mg Pt＋1 mg Ru）·cm^-2），在以甲烷为燃料时，质子交换膜燃料电池功率密度达到了5．4mW·cm^-2。     

玉米芯稀酸预处理和分步糖化与发酵工艺生产燃料乙醇的中试研究

利用正交试验在中试水平考察了玉米芯的稀硫酸预处理和分步糖化与水解生产乙醇的工艺。结果:最佳预处理工艺为稀硫酸浓度1.1%,温度120℃,固液比1∶8,时间3 h;酶解糖化最佳工艺为:起始底物浓度180 g/L,滤纸酶活:纤维二糖酶活=20 IU/g底物:7 IU/g底物,pH=5.0,48 h;利用运动发酵单胞菌发酵酶解液,35℃,48 h,发酵液中乙醇浓度最高67.8 g/L。     

酯化反应蒸馏过程的模型化及模拟研究

In this paper,a generalized model of the reactive distillation processes was developed via rate-based approach. The homotopy-continuation method was employed to solve the complicated nonlinear model equations efficiently. The simulation on the reactive distillation processes was carried out with the profiles of stage temperature,composition and flow rate for both vapor and liquid phases obtained. Based on careful analysis of the simulation results, the pitfalls in experimental design were detected. Finally, a software package for the simulation of reactive distillation processes was developed.