암모니아수를 이용한 이산화탄소 흡수분리공정에서 흡수액의 재생조건(온도, 압력)이 이산화탄소 흡수성능에 미치는 영향을 조사하였다. 실험에 사용된 흡수액은 탄산암모늄((NH4)2CO3)을 물에 용해시키어 CO2 로딩(mol CO2/mol NH3)이 0.5, 용액 내의 암모니아수 농도가 14, 20, 26 및 32 wt%로 되도록 제조하였고, 이산화탄소의 흡수에 앞서 재생압력(6~18 bar)을 조절하면서 120~160 ℃의 온도범위로 제조된 흡수액을 가열하여 재생하였다. 재생된 흡수액을 기포 반응기에 넣고 12 vol%의 CO2를 함유한 기체를 주입하여 흡수반응을 수행하였다. 실험결과 26 wt%의 암모니아수가 대체적으로 CO2 흡수량이 높았으며, 특히 재생온도가 150 ℃, 재생압력이 14 bar일 때의 CO2 흡수량은 본 연구의 실험조건에서 45 ml CO2/g solution으로 가장 높은 값을 보였다. 적정을 통해 재생된 용액을 분석한 결과 재생압력이_x000D_ 높아질수록 암모니아 손실량은 감소하고, 재생온도가 높아질수록 암모니아 손실량이 증가하였다. 또한 암모니아 농도증가에 따라 암모니아 손실량이 비례적으로 증가하였다. Electrolyte NRTL 모델을 사용하여 Aspen Plus에 적용한 결과 실험 데이터와 거의 일치함을 보였다.

In the field of the CO2 absorption process using aqueous ammonia, the effects of regeneration pressure and temperature on CO2 absorption performances of the aqueous ammonia were investigated. The absorbents were prepared by dissolving ammonium carbonate solid in water to grant the resulted solution 0.5 CO2 loading (mol CO2/mol NH3) and various ammonia concentration (14, 20, 26 and 32 wt%). As-prepared absorbents were regenerated at high pressure and temperature (over 120 ℃ and 6 bar) before the absorption test. The absorption test was carried out by injecting the simulated gas that contains 12 vol% of CO2 into a bubbling reactor. The introduction of 26 wt% of the ammonia concentration for CO2 absorption test resulted in the higher absorption capacities than other experimental conditions. In particular, when the absorbents with 26 wt% of the ammonia were regenerated at 150 ℃ and 14 bar, the highest absorption capacity, 45 ml CO2/g, was obtained. According to the analysis of absorbents using acid-base titration, the ammonia loss during the regeneration of the absorbents with a fixed ammonia concentration decreased as the regeneration pressure increased, while it increased as the regeneration temperature increased. In the condition of fixed regeneration pressure and temperature, as expected, the ammonia loss increased as the ammonia concentration increased. The measured CO2 loadings and ammonia concentrations of absorbents were compared to the values calculated by Electrolyte NRTL model in Aspen Plus.

Aqueous Ammonia Carbon Dioxide Absorption Regeneration Simulation

Fernando H, Venezia J, Rigdon C, Verma R, “Capturing King Coal, Deploying Carbon Capture and Storage Systems in the U.S. at Scale,” ISBN 978-1-56973-684-5.
Park HS, You JK, Hong WH, Kim JN, Korean Chem. Eng. Res., 47(2), 185 (2009)
You JK, Park HS, Hong WH, Park J, Kim JN, Korean Chem. Eng. Res., 45(3), 258 (2007)
You JK, Park H, Yang SH, Hong WH, Shin W, Kang JK, Yi KB, Kim JN, J. Phys. Chem. B, 112(14), 4323 (2008)
Kim YJ, You JK, Hong WH, Yi KB, Ko CH, Kim JN, Sep. Sci. Technol., 43(4), 766 (2008)
Diao YF, Zheng XY, He BS, Chen CH, Xu XC, Energy Conv. Manag., 45(13-14), 2283 (2004)
Wolsky AM, Daniels EJ, Jody BJ, Environ Prog., 13, 214 (1994)
Bai HL, Yeh AC, Ind. Eng. Chem. Res., 36(6), 2490 (1997)
Edwards TJ, Maurer G, Newman J, Prausnitz JM, AIChE J., 24, 996 (1978)
Yeh JT, Resnik KP, Rygle K, Pennline HW, Fuel Process. Technol., 86(14-15), 1533 (2005)
Yeh AC, Bai H, Sc. Total Environ., 228, 121 (1999)
Darde V, Thomsen K, Well W, Stenby E, Energy Procedia., 1, 1035 (2008)
Puxty G, Rowland R, Attalla M, Chem. Eng. Sci., 65, 915 (2010)