AMINOSILICA ADSORBENTS FOR POST-COMBUSTION CO2 CAPTURE: EFFECT OF STEAM AND OXYGEN ON LONG-TERM STABILITY

摘要

Aminosilica adsorbents are considered extremely promising candidates for post-combustion CO2 capture due to their high equilibrium CO2 adsorption capacities and favorable CO2/N2 selectivities. There is however, a lack of understanding about their stability under practical operating conditions. Typical flue gas exhaust contains 10-15% CO2, 5-10% O2, 4-5% water vapor, 2000 ppm SO2 (before flue gas desulfurization), 1500 ppm NO_x (before selective catalytic reduction) and the balance N2. Stability of amine adsorbents in the presence of oxygen and ppm levels of SO_x and NO_x are critical in determining the economic viability of an adsorbent. In addition, scalable, economically attractive regeneration methods have rarely been suggested, although use of low-pressure steam3 from waste heat sources in the power plant is one option under consideration4. Understanding steam-aminosilica interactions is thus important to enabling the design of adsorbents that can be regenerated using steam. In this study, we investigated the stability of various amine adsorbents in the presence of steam (referred to as steam stripping tests) as well as oxygen (referred to as oxidative stability tests) and identify important issues that will determine if supported amiosilica materials may one day be commercially viable adsorbents for post-combustion CO2 capture.