金属有机架构物(MOFs)吸附储氢系统强化传热措施分析

Analysis of Heat Conducting Enhancement Measures for Hydrogen Storage Systems by Adsorption on Typical Kinds of MOFs

选择MIL-101(Cr)并由溶剂热法合成,通过氢吸附平衡测试、在内容积为0.5 L储罐内进行充放氢试验和数值模拟,比较储罐内吸附床在添加膨胀石墨(ENG)和布置蜂巢状传热装置(HHED)下的储放氢性能。研究发现,在77.15~87.15 K、0~6 MPa范围,Toth方程预测氢在MIL-101(Cr)及其与ENG复合试样上吸附平衡数据的平均相对误差小于3.2%,氢在试样上的平均等量吸附热均为2.88 kJ/mol。77.15 K、0~3.5 MPa时,在与船舶燃料电池电力推进系统典型载荷适配的氢流率下,建立的二维数学模型对充气过程的数值模拟结果与测试值之间的平均相对偏差小于2%;与添加10 wt%的ENG相比,布置HHED的有效放气时间缩短14.3%、累计放气量增多15.5%、脱附率(DR)提高2.2%,在3.5 MPa时的可利用容积比率(UCR)提高10.6%。船用金属有机架构物(MOFs)储氢系统可选择布置HHED以缓解充放氢过程的热效应。

MIL-101(Cr)was selected and synthesized by an isothermal method.The measuring of adsorption equilibrium of hydrogen on the prepared sample was conducted,a storage vessel having a net volume about 0.5 L was designed and performed charge/discharge tests together with numerical simulation of hydrogen to comparatively evaluate the effect of adding expanded natural graphite(ENG)and equipping honeycomb heat exchanging device(HHED)on the performance of hydrogen storage on the vessel.Within the temperaturepressure ranges of 77.15-87.15 K and 0-6 MPa,the mean relative error between the experimental data and those predicted by Toth equation was less than 3.2%,and the mean value of the isosteric heat of hydrogen adsorption on both samples was about 2.88 kJ/mol.At 77.15 K and within the pressure range 0-3.5 MPa,while charging the vessel under a flow rate which was in correspondence with the fuel consumption of an onboard electrical propulsion system powered by fuel cell,the mean relative error between the results from two dimensional model based numerical simulations and those from experiments was less than 2%.In comparing with where 10 wt%ENG was added,equipping the HHED shortened the effective duration of charge about 14.3%by respectively increased the accumulated amount of discharge 15.5%.Desorption ratio(DR)of the adsorbent bed increased 2.2%,and the usable capacity ratio(UCR)improved 10.6%under 3.5 MPa.Equipping a HHED within an onboard hydrogen storage system by adsorption on MOFs is a better solution to mitigating the thermal effect on the charge and discharge processes.