고농도의 수소를 제조하기 위해, 흡착부과반응기를 이용한 스팀-메탄 개질 반응을 수행하였다. Cahn balance를 이용하여 흡착부과반응기에 사용되는 고온용 CO2 흡착제의 CO2 흡착량을 측정하였는데, K2CO3/hydrotalcite가 고온용 CO2 흡착제로서 적당하였다. K2CO3/hydrotalcite는 K2CO3 함침에 의한 염기성 증가와 기공 구조의 변형으로 450 ℃와 0.3 atm의 CO2 압력에서 0.575 mmol/g의 높은 CO2 흡착량을 보였다. 상업적 촉매, Ni/Al2O3 만을 이용한 500 ℃에서의 스팀-메탄 개질 반응은 스팀과 메탄의 반응물 비가 6:1에서는 과량의 스팀에 의해 촉매의 비활성화가 나타났지만, 3:1의 반응물 조건에서는 40.9% H2, 48.4% CH4, 10.7% CO2, 0.35% CO의 적절한 촉매 활성이 나타났다. 촉매와 CO2 흡착제가 동시에 충전된 흡착부과반응기를 이용한 스팀-메탄 개질 반응은 흡착제에 의한 CO2 흡착으로 평형 농도 이상의 고농도 수소를 얻을 수 있었는데, 반응물 공간 속도 5.81 mmol/gcat.-h에서 얻어지는 최대 수소 농도는 84.8%이었으며, 부생성물인 CO2가 파과되기 전까지 얻어진 H2 수율은 67.1%이었다.

To produce high concentration of hydrogen, steam-methane reforming reaction was carried out by using sorption enhanced reaction process. Cahn balance was used to check CO2 adsorption capacities of the CO2 adsorbents which could be applicable to the sorption enhanced reaction process at high temperature, and K2CO3/hydrotacite was selected as the most suitable CO2 adsorbent at the high temperature. The K2CO3/hydrotalcite showed a high CO2 adsorption capacity as much as 0.575 mmol/g at 450 ℃ and 0.3 atm of CO2 pressure because of its increased basicity and pore structure modification by K2CO3 impregnation. In the steam-methane reforming reaction using Ni/Al2O3 catalyst without CO2 adsorbent at 500 ℃, there was catalyst deactivation due to excess amount of steam in case of 6:1 steam and methane ratio, but there was a suitable catalyst activity such as 40.9% H2, 48.4% CH4, 10.7% CO2, and 0.35% CO of product composition for 3:1 reactants ratio. In the sorption enhanced reaction process using a reactor packed with the catalyst and the CO2 adsorbent simultaneously, high concentration of hydrogen above the equilibrium was generated via CO2 adsorption by the adsorbent, and the maximum concentration of hydrogen was 84.8% and the hydrogen yield was 67.1% until by-product CO2 broke-through.

Sorption Enhaced Reaction Process Hydrogen K2CO3/Hydrotalcite Steam-Methane Reforming

Office of Power Delivery, Hydrogen R&D Program, August, 7 (http://www.eren.doe.gov/hydrogen/pdfs/bk28424.pdf) (1999)
Anand M, Hufton J, Mayorga S, Nataraj S, Sircar S, Gaffney T, "Sorption Enhanced Reaction Process (SERP) for Production of Hydrogen," Proceedings of the 1996 U.S. DOE Hydrogen Program Review 1, 537-552 (1996)
Hufton J, Mayorga S, Gaffney T, Nataraj S, Rao M, Sircar S, "Sorption Enhanced Reaction Process (SERP) for the Production of Hydrogen," Proceedings of the 1998 U.S. DOE Hydrogen Program Review, 693-705 (1998)
Ding Y, Alpay E, Chem. Eng. Sci., 55(17), 3461 (2000) 
Ding Y, Alpay E, Chem. Eng. Sci., 55(18), 3929 (2000) 
Hufton J, Weigel S, Waldron W, Nataraj S, Rao M, Sircar S, "Sorption Enhanced Reaction Process (SERP) for the Production of Hydrogen," Proceedings of the 1999 U.S. DOE Hydrogen Program Review, 1-16 (1999)
Hufton J, Waldron W, Weigel S, Rao M, Nataraj S, Sircar S, "Sorption Enhanced Reaction Process (SERP) for the Production of Hydrogen," Proceedings of the 2000 U.S. DOE Hydrogen Program Review, 1-12 (2000)
Yang JI, Jung MH, Park JH, Kim JN, Theor. Appl. Chem. Eng., 6(2), 3109 (2000)
Twigg MV, Catalyst Handbook, 2nd ed., Wolfe, England, 230 (1989)
Numaguchi T, Shoji K, Yoshida S, Appl. Catal. A: Gen., 133(2), 241 (1995)