Effects of alkali-metal carbonates and nitrates on the CO2 sorption and regeneration of MgO-based sorbents at intermediate temperatures

• Published in: The Korean journal of chemical engineering 2016, 33(12), 201, pp.3448-3455
• Main Authors: Lee, Soo Chool, Cha, Su Ho, Kwon, Yong Mok, Park, Myung Gon, Hwang, Byung Wook, Park, Yong Ki, Seo, Hwi Min, Kim, Jae Chang
• Format: Article
• Language: English
• Subjects: Alkali metals; Biotechnology; Carbon dioxide; Carbon sequestration; Carbonates; Catalysis; Chemistry; Chemistry and Materials Science; Eutectic reactions; Impregnation; Industrial Chemistry/Chemical Engineering; Magnesium oxide; Materials Science; Metal nitrates; Nitrates; Regeneration; Reproducibility; Separation Technology; Sorbents; Sorption; Thermodynamics; 화학공학
• ISSN: 0256-1115; 1975-7220
• DOI: 10.1007/s11814-016-0185-4

The effects of alkali-metal carbonates and nitrates on the CO 2 sorption and regeneration of MgO-based sorbents were investigated in the presence of 10 vol% CO 2 and 10 vol% H 2 O in an intermediate temperature range, 300 to 450 °C. The CO 2 capture capacities of the MgO-based sorbents promoted with Na 2 CO 3 and K 2 CO 3 were 9.7 and 45.0 mg CO 2 /g sorbent, respectively. On the other hand, a MgO-based sorbent promoted with both Na 2 CO 3 and NaNO 3 exhibited the highest CO 2 capture capacity of 97.4mg CO 2 /g sorbent at 200 °C in 10 vol% CO 2 , which was almost ten-times greater than that of the MgO-based sorbent promoted with Na 2 CO 3 . The CO 2 sorption rate of these sorbents was higher than that of the MgO-based sorbents promoted with alkali-metal nitrates due to the formation of Na 2 Mg(CO 3 ) 2 or K 2 Mg(CO 3 ) 2 by the alkali-metal carbonate and the eutectic reaction of the alkali-metal nitrates. In addition, the reproducibility problem of double-salt sorbents obtained by the precipitation method was completely resolved by impregnating MgO with alkali-metal carbonates and nitrates. Furthermore, we found that their desorption temperatures are lower than those of the MgO-based sorbents promoted with alkali-metal carbonates due to the eutectic reaction during the regeneration process.