基于热力学平衡的高温固体氧化物电解水制氢模拟

SIMULATION OF HIGH TEMPERATURE SOLID OXIDE WATER ELECTROLYSIS FOR HYDROGEN PRODUCTION BASED ON THERMODYNAMIC EQUILIBRIUM

通过热力学、动力学及通量平衡分析,采用Aspen Plus软件建立固体氧化物电解(SOEC)制氢的热力学平衡模型,并与实验结果进行对比验证。分析运行温度、压力、阴极水蒸气摩尔分数和阳极空气流量对系统运行特性的影响,并建立考虑余热利用的SOEC制氢系统模型,研究余热利用对制氢效率的影响。当电流密度为1.0 A/cm^(2)时,不同操作条件下的系统可利用热量占总输入能量的比例在26.53%~46.63%之间;在采用余热利用时,余热利用率可达52.27%以上,系统制氢效率可提高14.43%~26.54%。在1223.15 K、0.1 MPa下,阴极通入50 mol/h含水量为50%的氢气、阳极通入10 mol/h空气,电流密度约为0.78 A/cm^(2)时,制氢效率达到最大值90.56%,与不采用余热利用条件下相比提高约25.89%。

The thermodynamics,kinetics,and flux balance of water electrolysis by solid oxide electrolysis cell(SOEC)were analyzed,and a thermodynamic equilibrium model was established using Aspen Plus.The predicted results were first compared with experimental data published in literature,and a good consistency was found.The effect of operating temperature,pressure,steam mole fraction of the cathode inlet gas,and air flow rate in the anode channel on the SOEC performance were then investigated.Finally,the influence of thermal energy reutilization on system efficiency was emphasized.The results indicated that the amount of thermal energy available for reutilization accounts for 26.53%-46.63% of the total input energy when the current intensity is 1.0 A/cm^(2).If the SOEC system were properly configured,the waste heat utilization rate would be>52.27% when the current intensity is 1.0 A/cm^(2).Compared with the case without heat reutilization,the system efficiency increases by 14.43%-26.54%.When operating at 0.1 MPa,1223.15 K,50% H_(2)O in the cathode channel and 10 mol/h air in the anode channel,the system efficiency reaches a maximum of 90.56% at a current intensity of 0.78 A/cm^(2),25.89% higher than that without heat reutilization.