(345d) Double layer structured amine-impregnated adsorbent using modified polyethyleneimine for CO2 capture

CO₂ emissions from fossil fuel combustion have been considered as a serious problem causing greenhouse effect in the international community. In order to reduce CO₂ emissions from large stationary sources including fossil fuel power plant, extensive researches have been carried out. Among various technologies for CO₂ capture, adsorption technologies using silica-supported amine sorbents have been shown high CO₂ adsorption capacity and amine efficiency. Also, for practical CO₂ capture, temperature swing adsorption (TSA) processes including high temperature regeneration with CO₂ or steam stripping have been proposed. Lots of researches have been conducted to improve CO₂ adsorption capacity but could not sufficient confirm physical and chemical stability of silica-supported amine sorbents for TSA cycle. Impregnated amines have physical stability problems (leaching out from the support at steam stripping) and chemical stability problems (irreversible formation of urea at high temperature and CO₂ condition in regeneration step). The lack of stability can cause the decrease of working capacity for long-term operation, so the physical and chemical stabilities of silica-supported amine sorbents are very important. This work investigated the stabilities of double layer structured adsorbent using modified polyethyleneimine (PEI). Epoxy modified PEI and diepoxide crosslinked PEI were impregnated in the first and second layers, respectively. The double layer structured adsorbent showed excellent physical and chemical stability by suppressing amine leaching and urea formation because of crosslinked PEI in the second layer.