Materials Science and Chemistry

Biography

Biography: Jeong-Hoon Kim

Abstract

Huge amount of by-product gas mixtures (H₂, CH₄, CO, CO₂, N_2, etc.) has been produced from steel industry in Korea and worldwide. Among the by-product gases, CH₄ and H₂ are included in coke oven gas (COG). CO₂ and CO is included in blast furnace gas (BFG) and Linz Donawitz gas (LDG) in steel industry. If they can be efficiently separated at high purity and recovery, they can be used valuably for carbon capture and utilization (CCU) producing chemical products such as methanol, ethanol, ethylene, acetic acid, etc. and therefore, contributing to reduction of global warming. There are typical separation technologies: cryogenic, adsorption, absorption and membrane. Membrane technology can be a promising new separation technology owing to cheap plant construction, easy operation, environmental friendliness etc. The economy and energy efficiency of membrane process depends mainly upon gas selectivity and gas permeability of membrane materials. This study shows the preliminary result for the gas separation properties of soluble polyimides as membrane materials - CO₂/N₂ (or CO₂/CO) and H₂/CH₄ (or CO₂/CH₄) selectivities and CO₂ and H₂ permeabilities. We have developed an alicyclic dianhydride-5-(2,5-dioxotetrahydrofuryl)-3-methyl-3-cyclohexene-1,2 dicarboxylic anhydride (DOCDA) based homo- and co-polyimides with various dianhydrides and diamines using m-cresol as a solvent, respectively. Thin dense membranes were prepared from the copolyimides to check their gas permeation properties with a time-lag apparatus. All homo- and copolyimides showed good solubility for organic solvents and excellent thermal stability. The synthesized polyimides showed excellent CO₂/N₂ (or CO₂/CO) and H₂/CH₄ (or CO₂/CH₄) selectivities, and high CO₂ and H₂ permeabilities. These results confirmed these polyimides could be used as membrane materials for the separation of CO_2, CH₄, H₂ and from by-product gases in steel industry.