Doo-Won Seo

Hydrogen Production by High Temperature Electrolysis Using Solid Oxide Electrolyzer Cells

Introduction High temperature electrolysis (HTE) is a promising technology to produce hydrogen with clean and massive manner. Higher temperature operation yield better performance due to the decrease in electrical energy demands for electrolysis and electrode overpotentials [2]. The operating mechanism of solid oxide electrolyzer cells (SOECs) are based on the inverse reaction of solid oxide fuel cells (SOFCs). However, operating conditions of SOECs are more sensitive in terms of mass (hydrogen + water vapor) distributions and electrical overpotentials. In this works, we evaluated the performance of NiO-YSZ supported SOECs with YSZ electrolytes and LSM electrodes.

Fabrication and Properties of the SiC Candle Filter by Vacuum Extrusion and Ramming Process

Porous SiC candle filter preforms were fabricated by extrusion and ramming process. To fabricate SiC candle filter preform, commercially available 85 -SiC powder and 44 mullite, CaC powder were used as the starting materials. The candle type preforms were fabricated by vacuum extrusion and ramming process, and sintered at 2 h in air atmosphere. The effect of forming method on porosity, density, strength (flexural and compressive strength) and microstructure was investigated. Also, corrosion test of the sintered candle filter specimens as forming method was performed at in IGCC syngas atmosphere. The sintered SiC filter which was formed by ramming process has more higher density and exhibit higher strength than extruded filter. Its maximum density and 3-point bending strength were 2.00 g/ and 45 MPa, respectively.

Effects of Carbon Fiber Arrangement on Properties of LSI C f -Si-SiC Composites

Carbon fiber fabric-silicon carbide composites were fabricated by liquid silicon infiltration (LSI) process. The porous twodimensional carbon fiber fabric performs were prepared by 13 plies of 2D-plain-weave fabric in a three laminating method, [0/90], [±45], [0/90/±45] lay-up, respectively. Before laminating, a thin pyrolytic carbon (PyC) layer deposited on the surface of 2D-plain weave fabric sheets as interfacial layer with C₃H? and N₂ gas at 900℃. A densification of the preforms for Cf-Si-SiC matrix composite was achieved according to the LSI process at 1650℃ for 30 min. in vacuum atmosphere. The bending strength of the each composite were measured and the microstructural consideration was performed by a FE-SEM.