(122h) Novel High Temperature Co2 Acceptor Using Zirconium-Based Alkali Mixed Oxides

The use of solid acceptors for CO2 sequestration has been widely used in many new applications. Recent developments in the field are based in the use of synthetic CO2 acceptors for high-temperature applications (400?700ºC), which include compounds such as lithium zirconate (Li2ZrO3) and lithium orthosilicate (Li4SiO4). Sodium-based oxides have been used in the past either as low-temperature (<250ºC) CO2 acceptors or as promoters for lithium-based acceptors. Recently Li2ZrO3 [1] and Na2ZrO3 [2] have been reported to present high thermal stability during CO2 capture at high temperatures. In this study we report the use of mixtures of Na2ZrO3/Li2ZrO3 base acceptors at high temperatures as an alternative for calcium based CO2 acceptors with the use of thermogravimetric (TGA), and X-ray diffraction (XRD) analysis. Na2ZrO3/Li2ZrO3-based acceptors were prepared by the solid-state and impregnated suspension methods. The effect of in situ and separate mixing precursors during synthesis is studied. Optimal Na2ZrO3/Li2ZrO3 molar ratio is examined by TGA as a function of carbonation/calcination performance at 600ºC/850ºC, respectively. Preliminary results indicate that Na2ZrO3/Li2ZrO3 mixture sorbent capacity is superior with respect to Na2ZrO3 or Li2ZrO3 alone. This mixture presents significantly greater carbonation kinetics than Li2ZrO3 and faster regeneration kinetics than Na2ZrO3, particularly towards the end of regeneration. The thermal stability, fast carbonation/calcination kinetics and improved sorbent capacity of Na2ZrO3/Li2ZrO3 mixture make this material ideal for applications where CO2 absorption play an essential role in order to make possible emerging energy-efficient power generation technologies (sorption enhanced hydrogen production, flue gas capture, etc)

[1] Jun-ichi, Ida; Rentian Xiong; Lin, Y.S., Sep. Purif. Technol. 2004, 1 (36), 41?51. [2] A. López-Ortiz, N. G. Pérez Rivera, A. Reyes Rojas and D. Lardizabal Gutiérrez, Sep. Sci. Technol. (39) 2004, 3563?3579