面向海上风电的碱性电解水制氢系统热力学分析与优化设计

Thermodynamic analysis and optimization design of alkaline water electrolysis hydrogen production system for offshore wind power

[目的]为了最大化利用电能与海水资源,针对海上风电的碱性电解水(AWE)制氢系统进行热力学分析和优化设计,研究工作压力、工作温度、碱液流量等对系统运行特性的影响。[方法]基于热力学、电化学及质量平衡模型,通过Aspen Plus软件建立碱性电解水制氢的热力学平衡模型,并与实验结果进行对比验证。[结果]结果表明,此方案碱性电解水制氢系统最佳工作压力和工作温度分别为9 bar和70℃,最佳碱液流量为1600 t/h。系统能量损失和㶲损随输入电流密度的增加而增加。碱性电解输入电流密度为3000 A/m^(2)时,系统能量效率和㶲效率分别为63.58%和57.27%,系统能量损失占总能量投入的26%,其中电解槽㶲损最高,占系统总㶲损的93.39%。[结论]通过该参数优化方法,可以得到合适的工作参数范围,能够为海上风电制氢参数选择提供参考。

[Objectives]In order to fully leverage electricity and seawater resources,this paper carries out the thermodynamic analysis and optimization design of an alkaline water electrolysis(AWE)hydrogen production system for offshore wind power.The focus comprises the impacts of operating pressure,temperature and lye flow rate on the operational characteristics of the system.[Methods]Thermodynamic,kinetic and flux balance analyses are carried out to develop a thermodynamic equilibrium model for hydrogen production by alkaline water electrolysis using Aspen Plus software,which is then validated in comparison with the experimental results.[Results]The optimum working pressure and temperature of the alkaline water electrolysis hydrogen production system are 9 bar and 70℃respectively,and the optimum lye flow rate is 1600 t/h.The system energy loss and exergy loss increase with the increase of input current density.When the alkaline water electrolysis input current density reaches 3000 A/m^(2),the system energy efficiency and exergetic efficiency are 63.58%and 57.27%respectively,and the system energy loss accounts for 26%of the total energy input,of which the exergy loss of the electrolyzer is the highest,accounting for 93.39%of the total exergy loss of the system.[Conclusions]Through this parametric optimization method,a suitable range of operating parameters can be obtained,providing useful references for the selection of offshore wind power hydrogen production parameters.