Optimization of Oxygen Permeable Membrane by Applying to Hydrogen Production System Based on Partial Oxidation of Methane

将基于氧化铈的透氧膜安装在不锈钢分离器上作为模块，并在实现用于氢气生产的高系统效率的背景下优化其混合电导率。对于2006财年，1）氧气渗透膜组件的制造及其甲烷重整性能，以及2）膜的混合氧离子和电子电导率进行了研究。通过在780至950℃左右操作模块获得预期的氢气量。通过Hebb-Wagner极化技术分离混合的离子和电子电导率;在900℃下，发现通过降低空气的压力，在10^ bar的氧分压下，主要载流子从氧化物离子转换为电子<-7>。在2007年度，对1）透氧膜组件的热平衡和2）基于固体氧化物电解质的氢电联产系统的火用分析进行了检查。在780℃、甲烷输入量为150 sccm的条件下，膜组件的发热量为8.4W。作为固体氧化物燃料电池系统，分别采用20mol%Sm掺杂CeO_2、Ba_<0.5>Sr_<0.5>Co_<0.8>Sr_<0.2>O_&lt;3-δ&gt;、（Ce_<0.8>Sm_<0.2>）O_2-50vol%NiO作为电解质、阴极和阳极。以Ar-10%CH4为燃料，在700℃，电流密度为288 mA/cm^2时，获得了最高的功率密度131 mW/cm^2。在此基础上绘制了火用罗盘图，在最佳工况下，火用效率达到46.7%。另一方面，在对应于氧渗透膜的短路模式下，效率为22.8%。

A ceria-based oxygen permeable membrane was mounted on a stainless-steel separator to be a module and to optimize its mixed conductivity in the context of achieving high system efficiency for hydrogen production. For FY2006, 1) fabrication of the oxygen permeable membrane module and their methane reforming properties, and 2) mixed oxide-ion and electronic conductivity of the membrane were investigated. Expected amount of hydrogen was obtained by operating the module at around 780 to 950℃. The mixed ionic and electronic conductivities were separated by means of the Hebb-Wagner polarization technique; at 900℃, major carrier was found to be switched from oxide-ion to electron at an oxygen partial pressure of 10^<-7> bar by reducing the pressure from air. For FY2007, 1) heat balance of the oxygen permeable membrane module, and 2) exergy analysis of co-production system of hydrogen and electricity based on solid-oxide electrolytes were examined. Based on the mixed conductivity mentioned above, under an operating condition at 780℃ and a rate of 150 sccm methane input, the membrane module was found to emit a heat of 8.4 W. As a solid-oxide fuel cell system, 20mol%Sm-doped CeO_2, Ba_<0.5>Sr_<0.5>Co_<0.8>Sr_<0.2>O_<3-δ>, (Ce_<0.8>Sm_<0.2>)O_2-50vol%NiO were used as an electrolyte, cathode and anode, respectively. By supplying Ar-10%CH_4 as a fuel, the highest power density of 131 mW/cm^2 was attained at a current density of 288 mA/cm^2 at 700℃. Based on these value, an exergy compass diagram was constructed; under the optimum condition, an exergy efficiency reached to 46.7%. On the other hand, under short-circuited mode, which corresponds to an oxygen permeable membrane, the efficiency was 22.8%.