Development of the Pure Hydrogen Production Process from Reductive Gas by Using the Solid Oxide Electrolysis Cells

Our research and development aims to develop an efficient process technology for high-purity hydrogen production with simple system component by using various reductive gases especially by using low calorie gases such as biogas. This process is a high temperature steam electrolysis process using solid oxide electrolysis cells with reductive gas supplied into the anode of the cells. For developing the high performance electrolysis cells, tubular electrolysis cells with thin electrolyte of yttria stabilized zirconia(YSZ) were fabricated. The performance of the electrolysis cell was evaluated by an electrolysis test for single cell using a simulated gas, determining that electrolysis could be achieved at lower voltage than 0.4V with a current density of 320mA/cm2 at 730 degree C. Then, a cell stack of 7 tubular electrolysis cells connected in series was fabricated and the low voltage electrolysis with the cell stack and the hydrogen production from the biogas were successfully demonstrated.