매체순환식 가스연소기 산소공여입자로 NiO 계열 산소공여입자를 사용할 경우 고온 조건(>900 ℃)에서 온도가 증가함에 따라 환원반응 배출기체 중 CO 농도가 증가하게 되며, 이에 의해 연료전환율과 CO2 선택도가 감소하게 된다. 이러한 고온 환원반응성 저하를 개선하기 위한 방법으로 매체순환 가스연소기에 적용 가능한 금속산화물들에 대해 온도변화에 따른 평형 CO 농도를 계산 및 비교하여 반응성 개선이 가능한 금속산화물을 선정하였다. 선정된 금속산화물을 NiO 계열 산소공여입자와 물리적으로 혼합하는 방법을 적용하여 고온 환원반응성 개선이 가능한지를 회분식 유동층 실험장치를 이용하여 측정 및 해석하였다. 900~1000 ℃ 범위에서 기존 NiO 계열 입자(OCN706-1100) 만을 사용한 경우에 비해 Co3O4 계열 입자(Co3O4/CoAl2O4)를 10% 혼합한 경우가 연료전환율 및 CO2 선택도가 높게 나타났으며 환원반응 배출기체 중 CO의 농도가 감소하는 경향을 나타내어 Co3O4 계열 산소공여입자를 함께 사용하는 방법으로 고온 환원반응성 개선이 가능함을 확인할 수 있었다.

When we use NiO based particle as an oxygen carrier in a chemical looping combustion system, the fuel conversion and the CO2 selectivity decreased with increasing reaction temperature within high temperature range (>900 ℃) due to the increment of exhaust CO concentration from reduction reactor. To improve reduction reactivity at high temperature, the applicable metal oxide component was selected by calculation of the equilibrium CO concentration of metal oxide components. After that, feasibility of reduction reactivity improvement at high temperature was_x000D_ checked by using solid mixture of the selected metal oxide particle and NiO based oxygen carrier. The reactivity was measured and investigated using batch type fluidized bed. The solid mixture of Co3O4/CoAl2O4(10%) and OCN706-1100(90%) showed higher fuel conversion, higher CO2 selectivity and lower CO concentration than OCN706-1100 (100%) cases. Consequently, we could conclude that improvement of reduction reactivity at high temperature range by adding some Co3O4 based oxygen carrier was feasible.

Chemical-Looping Combustion Oxygen Carrier Syngas Solid Mixture Reduction Reactivity Improvement

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