Structure Effects of Potassium-Based TiO2 Sorbents on the CO2 Capture Capacity

Abstract

The CO 2 absorption properties of potassiumbased TiO 2 sorbents prepared by calcining at various temperatures from 300 to 700°C under N 2 and air were investigated in a fixed bed reactor at 60°C. The CO 2 capture capacity of the sorbent was changed dramatically depending on the structure of the sorbent, which was affected by calcination atmosphere, as well as calcination temperature.

Low-temperature solid carbon dioxide carriers

“…For K 2 CO 3 /AC, K 2 CO 3 /TiO 2 , and K 2 CO 3 /ZrO 2 , the CO 2 desorption peak was consistent with the production of KHCO 3 as the only product for these sorbents (Lee et al, 2009;Lee & Kim, 2007). The calcination temperature of K 2 CO 3 /TiO 2 must be lower than 300 C (Lee et al, 2010) because it was found that its carbonation reaction capacity rapidly decreased when the calcination temperature increased from 300 to 700 C, and some byproducts such as K 2 Ti 2 O 5 , K 2 Ti 6 O 13 , and K 2 Ti 4 O 9 were also formed from K 2 CO 3 and TiO 2 . The TPD results for K 2 CO 3 /MgO (Lee, Chae, et al, 2008;Lee & Kim, 2007;Xiao et al, 2011) show three CO 2 peaks, one occurs at 130 C (as expected for KHCO 3 production), another occurs at around 300 C (which suggests the presence of Mg(OH) 2 ), and the last is seen at a temperature above 340 C (attributed to K 2 Mg(CO 3 ) 2 and K 2 Mg(CO 3 ) 2 $4(H 2 O)).…”

“…The energy consumption for the CO 2 recovery was evaluated in multiple tests on CO 2 sorption and release. Further research on CO 2 capture using dry potassium-based sorbents was conducted by Kyungpook National University (Lee, Chae, et al, 2008;Lee et al, 2009Lee et al, , 2010Lee & Kim, 2007), KEPRI (Lee, Eom, et al, 2011), and the Korea Institute of Energy Research (KIER) Seo et al, 2005Seo et al, , 2009. Kyungpook National University has been attempting to develop various sorbent formulations as well as to carry out the basic research.…”

“…After loading these active components on supports, the difference in reaction processes apparently disappears for potassium carbonate obtained from different sources, indicating that the reaction paths for the sorbents depend mainly on the supports. KHCO 3 is the only product observed for the carbonation of sorbents such as K 2 CO 3 /AC (Hayashi et al, 1998;Hirano et al, 1995;Lee & Kim, 2007;Shigemoto et al, 2006), K 2 CO 3 /TiO 2 Lee et al, 2010), and K 2 CO 3 /ZrO 2 (Lee et al, 2009). KAl(CO 3 ) 2 (OH) 2 is formed in the carbonation process of K 2 CO 3 / Al 2 O 3 Lee & Kim, 2007;Lee, Kwon, et al, 2011).…”

“…Sorbents such as K 2 CO 3 /AC (Hayashi et al, 1998;Hirano et al, 1995;Lee et al, 2009Lee et al, , 2010Lee, Chae, et al, 2008;Lee & Kim, 2007;Shigemoto et al, 2006), K 2 CO 3 /TiO 2 Lee et al, 2010;Lee & Kim, 2007), K 2 CO 3 /ZrO 2 (Lee et al, 2009;Lee & Kim, 2007), and K 2 CO 3 /Al 2 O 3 (Lee et al, 2009;Lee, Chae, et al, 2008;Lee & Kim, 2007) show excellent CO 2 capture capacities, except for some sorbents Lee & Kim, 2007) such as K 2 CO 3 /SiO 2 , K 2 CO 3 / USY (ultra-stable Y zeolite), K 2 CO 3 /CsNaX (prepared by the ion-exchanged method with NaX zeolite and cesium acetate), and K 2 CO 3 /CaO. The K 2 CO 3 /MgO sorbent (Lee, Chae, et al, 2008;Lee & Kim, 2007) achieves a higher carbonation reaction capacity than the theoretical value.…”

“…, , Green, Turk, Portzer, et al (2002a), Green, Turk, Portzer, et al (2002b), and Green et al (2003aGreen et al ( , 2003c 51e85 Fluidized bed 101.2e170.9 120 Green, Turk, Gupta, Harrison, and Liang (2001) 60 Entrained bed 1.14 144e170 and Nelson, Green, et al (2009) 60 Fixed bed 146.5e163.8 120 Green et al (2003b) Calcined trona 60e80 Fluidized bed 45.6e78.3 120 and Green, Turk, Portzer, et al (2002a) 60 Entrained bed 1.18 144e170 and Nelson, Green, et al (2009) RTI's Na-based sorbents 60 Fluidized bed 7.1e8.8 120e150 and 60 Entrained bed 6.1e9.2 144e170 and Nelson, Green, et al (2009) 60 Downflow reactor 4.5e12 e Nelson, Green, et al (2009) and Green, Nelson, Turk, Box, Li, et al (2005) Na 2 CO 3 /Al 2 O 3 60 Fixed bed 7 150 Lee et al (2004) and Na 2 CO 3 /AC 60 Fixed bed 18 150 Lee et al (2004) and Sorb NX35 Lee et al (2004), Lee and Kim (2007), , Lee et al (2009Lee et al ( , 2010, Lee, Chae, et al (2008), Hayashi et al (1998), Hirano, Shigemoto, Yamaha, and Hayashi (1995), and Shigemoto, Yanagihara, Sugiyama, and Hayashi (2006) 60 Fluidized bed 66.4e94.6 200 Zhao, Chen, and Zhao (2009a) and Zhao, Chen, and Zhao (2011) K 2 CO 3 /Al 2 O 3 60 Fixed bed 38e89.0 350 Lee and Kim (2007), , and Lee et al (2009) 60 Fluidized bed 40.9e106.6 350 Zhao et al (2009aZhao et al ( , 2011Zhao et al ( , 2010a, and Zhoa, Chen, Zhao, Wu, and Dong (2012) K 2 CO 3 /MgO ...…”