Cylindrical high temperature steam electrolytic electrolysis cell

摘要

PURPOSE: To reduce the thermal stress generated in operation and to prevent the deterioration and breakage of each layer of the cell by equalizing the thermal expansion coefficient of the insulating base pipe of the cylindrical high-temp. steam electrolytic cell formed by successively laminating a porous inner electrode, dense electrolyte and porous electrolyzing electrode on the periphery of the insulating base pipe practically with the thermal expansion coefficient of the electrode material. ;CONSTITUTION: The thickness of the insulating base pipe as the cell layer is controlled to about 2mm and those of the electrolyte and electrode to about 0.1mm, a film is formed at ≥1000°C, and the cell is operated at about 1000°C. Accordingly, the cell is deformed in operation due to the difference in thermal expansion coefficient among the layers and easily broken because of the residual stress after cooling. Consequently, the insulating base pipe is formed by firing a mixture of MgO and MgAl₂O₄ to make the thermal expansion coefficient almost equal to that of the electrode material. The weight ratio of the MgO to Al₂O₄ is preferably controlled to 65/35 to 83/17 and the thermal expansion coefficient to 1.1 to 1.2×10⁵ to reduce the tensile residual stree acting on the electrode layer to ≤1/10 of the conventional one.;COPYRIGHT: (C)1996,JPO