高差压质子交换膜水电解制氢系统设计及性能实验

Design and Performance Test of High Differential Pressure PEM Water Electrolysis System

研制了制氢量为0.3 Nm^(3)/h,输出压力为3.0 MPa的差压PEM(质子交换膜)水电解制氢装备,并测试分析了装置的电化学、气体纯度和水电解过程中质子膜内水分迁移等方面的性能。结果表明:装置在压力3.0 MPa、温度45℃、电流密度1 A/cm^(2)工况下,小室平均电压为1.843 V,氧中氢体积分数浓度为14 500×10^(-6),排水与氢气物质的量之比为4左右。结论:电池堆电化学特性及氢气安全性均满足设计要求,提升电堆极板的表面状况和导电性能将提高电堆整体能效。阴极出水低压释氢以及原位催化除氢,是降低氧中氢浓度、保障安全的有效途径。差压下水分传输系数与电流密度成正比关系,而等压下成反比关系,且差压下的值小于等压的值。

In this paper,a facility of PEM(proton exchange membrane),with 0~0.3 Nm^(3)/h of hydrogen flow rate and 0~3.0 MPa of pressure,has been developed.Performances of electrochemistry,concentration of hydrogen in oxygen and wa-ter transportation in proton exchange membrane were tested and analysed.Results:at the condition of 3.0 MPa of cath-ode pressure,45℃of operational temperature and 1 A/cm^(2),the facility have 1.843 V of average of cell voltage,80%of direct-current efficiency for electrolyser,14500×10^(-6) of hydrogen concentration in oxygen,and 4 of the ratio of cathode water transportation rate to hydrogen flow rate in terms of mole,of which all meet designed requirements.Conclusions:Electrolyzer in term of electrochemistry performance and safety satisfy requirements of design.The energy efficiency of electrolyzer will increase with improving surface condition and conductive performance.The hydrogen dissolution from water in lower pressure condition and eliminating hydrogen in situ catalysis are effective methods for decreasing of hydro-gen concentration in oxygen and safe operation.Transformation coefficient of water in differential pressure is proportion-al to current density,while inverse in the same pressure between cathode and anode,more over the value in the differen-tial pressure is higher than the one in the same pressure.