摘要
利用水电解技术将可再生能源转化为氢能是一条理想的绿色制氢途径。在常规水电解中,膜在电解装置的成本中占有较大比例并带来较高的电阻,而膜的降解往往是影响电解系统寿命的关键。无膜水电解技术可以有效避免膜带来的成本、寿命和电阻,具有重大的研究意义。建立了穿流电极无膜水电解的二维数值模拟模型,综合考虑了质量传递、动量传递、电化学反应过程以及电荷传递过程及其耦合关系。分析考察了由于电极活化、气泡覆盖活性面积以及欧姆阻抗导致的过电位在总电压中的占比,着重研究了电解液的流速以及电极间隙厚度对整个系统电压降的影响。结果表明,在总电压中气泡覆盖活性面积以及欧姆阻抗导致的过电位占据主要地位,这两者可以通过增加电解液流速和减小电极间隙厚度来降低。为了保证系统的电解效率的同时降低间隙内的气体含量,需要对电解液流速、电流密度大小以及电极间隙厚度进行匹配调整,从而达到最适的运行工况。
It is an ideal way to produce hydrogen by converting renewable energy into hydrogen energy using hydroelectricity.At conventional electrolysis,membrane occupies a large proportion in the cost of electrolytic device and brings high resistance,and the degradation of membrane is a short board that affects the life of electrolytic system.Membrane-less water electrolysis technology can effectively avoid the cost,life and resistance brought by membrane,which has great research significance.A two-dimensional numerical simulation model of membrane-less electrolysis with flow-through electrode was developed in this study firstly,taking the mass transport,momentum transport,electrochemical reaction,charge transport and their coupling relationship into comprehensive consideration.The ratio of overpotential in the total voltage caused by electrode activation,active area covered by bubbles and ohmic impedance was analyzed,and the influence of electrolyte flow rate and electrode gap thickness on the voltage drop of the whole system was emphatically studied.The results show that the active area covered by bubbles and the overpotential caused by ohmic impedance play a major role in the total voltage,both of which can be reduced by increasing electrolyte flow rate and decreasing electrode gap thickness.In order to ensure the electrolytic efficiency of the system and reduce the gas content in the gap,it is necessary to coordinate the electrolyte flow rate,current density and electrode gap thickness,so as to achieve the optimal performance.
作者
沈岑
刘伯伦
闵洛夫
许卫
王宇新
SHEN Cen;LIU Bolun;MIN Luofu;XU Wei;WANG Yuxin(School of Chemical Engineering and Technology,State Key Laboratory of Chemical Engineering,Tianjin Key Laboratory of Membrane Science and Desalination Technology,Tianjin University,Tianjin 300350,China;Tianjin Mainland Hydrogen Equipment Co.,Ltd.,Tianjin 301609,China)
出处
《化学工业与工程》
CSCD
北大核心
2024年第5期61-72,共12页
Chemical Industry and Engineering
基金
化学工程国家重点实验室课题(SKL-CHE-21T01)
关键词
碱性水电解
无膜
数值模拟
优化设计
alkaline water electrolysis
membrane-less
numerical simulation
optimization design
