알칼리금속염으로 처리된 활성탄에 대한 CO2의 흡착특성

유동관; 김성현

Journal of the Korean Industrial and Engineering Chemistry, Vol.9, No.2, 286-293, April, 1998

Export Citation

알칼리금속염으로 처리된 활성탄에 대한 CO2의 흡착특성

Adsorption Characteristics of CO₂ on Activated Carbons Treated with Alkali-metal Salts

유동관, 김성현

초록

연소배가스로부터 CO₂를 선택적으로 분리하기 위한 활성탄 흡착공정 사용시 흡착능 향상을 위하여 CO₂와 친화력이 있는 화합물을 함침시키는 방법과 KOH를 함침시킨 후 고온에서 열처리하므로서 활성화시키는 방법이 사용되었다. 알칼리금속, 알칼리토금속, 또는 전이금속의 염화물을 함침시킨 활성탄에 대한 CO₂의 흡착량을 측정한 결과 함침 전의 활성탕의 흡착량보다 적었다. 이것은 함침되는 물질이 CO₂에 대한 친화력이 없이 단지 활성탕의 미세기공만 막는 결과임을 알 수 있었다. 알칼리금속수산화물 중 KOH를 함침시킨 활성탄에 대한 CO₂의 파과실험 결과 유입되는 기체에 수분이 있을 경우 흡착량이 증가했는데 이것은 KOH가 CO₂를 흡수하는 성질 때문이었다. 그러나 이 흡착제에 함친된 KOH가 CO₂와 반응하여 K₂CO₃로 변함에 따라 재현성이 없음을 알 수 있었다. KOH를 함침시킨 후 800℃에서 열처리하여 활성화시킨 활성탄의 경우 함침된 KOH의 양이 증가할수록 CO₂의 흡착량이 증가했으며, KOH와 활성탄의 무게비(KOH/Activated-Carbon)가 4일 때 최대였다. 이 흡착제에 대해 온도별로 측정된 CO₂의 흡착량으로부터 Clausius-Clapeyron식을 이용하여 등량흡착열을 구했다. 그리고 고정층 파과실험을 통해 CO₂농도와 유속에 따른 파과특성을 살펴보았다.

Two methods were used to enhance the adsorption capacity of activated carbons. One is to impregnate activated carbons with chemical compounds which have a good affinity for CO₂. The other is to activate by heat-treating after impregnation with KOH on activated carbons(AC). The chemical compounds impregnated on AC were alkali metal, alkaline earth metal, and transition metal chlorides. The adsorption capacity of CO₂ on AC impregnated with these metals was less than that of pure AC. These compounds have not the chemical affinity for CO₂ and obstruct the micropore of AC. The experiment of breakthrough for CO₂ on AC impregnated with KOH showed the increase of the adsorbed amount of CO₂ in influent gases containing water vapor. This means that KOH adsorbes CO₂ gas. However, the adsorbents impregnated with KOH had not the reproducibility because of the production of K₂CO₃ by the reaction of KOH with CO₂. The amount of CO₂ adsorbed on the heat-treated AC at 800℃ increased with the amount of impregnation. The adsorption capacity of CO₂ was the largest when the ratio of weight of KOH to AC equal to 4. The isosteric heat of adsorption was calculated by the equation of Clausius-Clapeyron form adsorption capacity data of CO₂ for the temperature change. In addition, the characteristics of CO₂ breakthrough curve were surveyed for the change of flow rate and concentration.

[References]

Yang RT, "Gas Separation by Adsorption Process," Butter-worth Publishers, Boston, U.S.A. (1987)
Otowa T, Yamada M, Tanibata R, Kawagami M, Vansant EF, Dewolfs R, Elsevier, 263, New York, NY (1990)
Kim JY, Lee JG, Hong I, Lee SS, HWAHAK KONGHAK, 34(5), 668 (1996)
Min BM, Shon HS, Kim SH, Yoo KP, HWAHAK KONGHAK, 31(6), 693 (1993)
Marsh H, Murdie N, Edward I, "Chemistry and Physics of Carbon," ed. P.L. Walker, and P.A. Thrower, Dekker, 20, 213, New York, NY (1987)
한국에너지기술연구소, "CO2 흡착분리공정 개발 연구"에 관한 최종 보고서 (1996)
Whaley TP, "Comprehensive Inorganic Chemistry," 1st ed., ed. A.F. Trotman-Dickenson, 454, Pergamon Press, Oxford (1976)
Ross S, Olivier JP, "On Physical Adsorption," Interscience, New York (1964)
Loughlin KF, Hansanain MA, Abdul-Rehman HB, Ind. Eng. Chem. Res., 29, 1535 (1990)

[Referenced By]

[1] Yang RT, "Gas Separation by Adsorption Process," Butter-worth Publishers, Boston, U.S.A. (1987)

[2] Otowa T, Yamada M, Tanibata R, Kawagami M, Vansant EF, Dewolfs R, Elsevier, 263, New York, NY (1990)

[3] Kim JY, Lee JG, Hong I, Lee SS, HWAHAK KONGHAK, 34(5), 668 (1996)

[4] Min BM, Shon HS, Kim SH, Yoo KP, HWAHAK KONGHAK, 31(6), 693 (1993)

[5] Marsh H, Murdie N, Edward I, "Chemistry and Physics of Carbon," ed. P.L. Walker, and P.A. Thrower, Dekker, 20, 213, New York, NY (1987)

[6] 한국에너지기술연구소, "CO2 흡착분리공정 개발 연구"에 관한 최종 보고서 (1996)

[7] Whaley TP, "Comprehensive Inorganic Chemistry," 1st ed., ed. A.F. Trotman-Dickenson, 454, Pergamon Press, Oxford (1976)

[8] Ross S, Olivier JP, "On Physical Adsorption," Interscience, New York (1964)

[9] Loughlin KF, Hansanain MA, Abdul-Rehman HB, Ind. Eng. Chem. Res., 29, 1535 (1990)