TY - JOUR
T1 - Influence of the concentration of CO 2 and SO 2 on the absorption of CO 2 by a lithium orthosilicate-based absorbent
AU - Pacciani, R.
AU - Torres, J.
AU - Solsona, P.
AU - Coe, C.
AU - Quinn, R.
AU - Hufton, J.
AU - Golden, T.
AU - Vega, L. F.
PY - 2011/8/15
Y1 - 2011/8/15
N2 - A novel, high temperature solid absorbent based on lithium orthosilicate (Li 4SiO 4) has shown promise for postcombustion CO 2 capture. Previous studies utilizing a clean, synthetic flue gas have shown that the absorbent has a high CO 2 capacity, >25 wt %, along with high absorption rates, lower heat of absorption and lower regeneration temperature than other solids such as calcium oxide. The current effort was aimed at evaluating the Li 4SiO 4 based absorbent in the presence of contaminants found in typical flue gas, specifically SO 2, by cyclic exposure to gas mixtures containing CO 2, H 2O (up to 25 vol. %), and SO 2 (up to 0.95 vol. %). In the absence of SO 2, a stable CO 2 capacity of ∼25 wt % over 25 cycles at 550 °C was achieved. The presence of SO 2, even at concentrations as low as 0.002 vol. %, resulted in an irreversible reaction with the absorbent and a decrease in CO 2 capacity. Analysis of SO 2-exposed samples revealed that the absorbent reacted chemically and irreversibly with SO 2 at 550 °C forming Li 2SO 4. Thus, industrial application would require desulfurization of flue gas prior to contacting the absorbent. Reactivity with SO 2 is not unique to the lithium orthosilicate material, so similar steps would be required for other absorbents that chemically react with SO 2.
AB - A novel, high temperature solid absorbent based on lithium orthosilicate (Li 4SiO 4) has shown promise for postcombustion CO 2 capture. Previous studies utilizing a clean, synthetic flue gas have shown that the absorbent has a high CO 2 capacity, >25 wt %, along with high absorption rates, lower heat of absorption and lower regeneration temperature than other solids such as calcium oxide. The current effort was aimed at evaluating the Li 4SiO 4 based absorbent in the presence of contaminants found in typical flue gas, specifically SO 2, by cyclic exposure to gas mixtures containing CO 2, H 2O (up to 25 vol. %), and SO 2 (up to 0.95 vol. %). In the absence of SO 2, a stable CO 2 capacity of ∼25 wt % over 25 cycles at 550 °C was achieved. The presence of SO 2, even at concentrations as low as 0.002 vol. %, resulted in an irreversible reaction with the absorbent and a decrease in CO 2 capacity. Analysis of SO 2-exposed samples revealed that the absorbent reacted chemically and irreversibly with SO 2 at 550 °C forming Li 2SO 4. Thus, industrial application would require desulfurization of flue gas prior to contacting the absorbent. Reactivity with SO 2 is not unique to the lithium orthosilicate material, so similar steps would be required for other absorbents that chemically react with SO 2.
UR - http://www.scopus.com/inward/record.url?scp=80051771507&partnerID=8YFLogxK
U2 - 10.1021/es201269j
DO - 10.1021/es201269j
M3 - Article
C2 - 21756001
AN - SCOPUS:80051771507
SN - 0013-936X
VL - 45
SP - 7083
EP - 7088
JO - Environmental Science and Technology
JF - Environmental Science and Technology
IS - 16
ER -
