(105d) Effect of Preparation Parameters On Mixed Amine Functionalized Silica Sorbents for CO2 Capture

Effect of preparation parameters on mixed amine functionalized silica sorbents for CO₂ capture

Adefemi Egbebi^{1, 2}, Sonia Hammache^{1, 2}, and McMahan L. Gray¹

¹US DOE-National Energy Technology Laboratory, Pittsburgh, PA

²URS, Pittsburgh, PA

Global climate change has been linked to growing atmospheric concentrations of carbon dioxide. Therefore the development of practical methods to remove, reduce or prevent the release of anthropogenic CO₂ is prudent to slow this increase.  The most mature technology for the separation of CO₂ from flue gas streams from power plants is via liquid amine scrubbing which is considered expensive and energy-intensive. The potential therefore exists for the development of alternative CO₂ removal technologies, including the use of solid amine-based sorbents among others, capable of less energy-intensive CO₂separation.

Previous work in our laboratory investigated co-impregnated mixed amine (Polyethyleneimine (PEI) + 3-aminopropyltriethoxysilane (APTES) / Silica) solid sorbents with the goal of improving sorbent performance in terms of its CO₂ uptake capacity, thermal and hydrolytic stability as well as the kinetics during sorption and regeneration cycles. Results showed improved CO₂capture capacity and stable performance of the mixed amine sorbent relative to a single amine (PEI) sorbent.

Current work investigates the effects of synthesis parameters/variables such as bath temperature, solvent type and impregnation sequence on sorbent performance. Modified Pressure Swing Adsorption (PSA) tests were conducted with a thermogravimetric analyzer (TGA) on two sorbents with same composition of 15 wt. % PEI: 15% APTES: 70 % SiO₂ but with different solvents used during their syntheses - methanol for one and methanol-hexane mixture for the other. Adsorption was performed using dry 10% CO₂ /N₂ feed gas and desorption was conducted with 100% N₂ feed gas while temperature was kept the same at 100°C. Preliminary results show negligible differences between the sorbents in terms of CO₂uptake capacity and thermal stability.

The effect of various preparation parameters will be elucidated from the results of TGA, fixed bed reactor and other characterization experiments on sorbents and will be presented.