기포유동층과 고속유동층의 2탑 연결 가압순환유동층으로 조업되는 매체순환식 가스연소기의 설계와 조업조건 선정을 위해 산소공여입자의 최소유동화속도와 고속유동층으로의 전이유속을 측정 및 고찰하였다. 층물질로 매체순환식 가스연소기의 산소공여입자인 NiO/bentonite (평균입경: 0.181 mm, 입자밀도: 4,080 kg/m³)를 사용하여 가압 기포유동층(내경 0.052 m, 높이 1.66 m)에서 층압력강하를 측정하여 온도(25-1,000 ℃)와 압력(1-6 atm)의 변화에 따른 최소유동화속도의 변화를 측정 및 고찰하였고 고온순환유동층(내경 0.02 m, 높이 2.0 m)에서 emptying time method에 의해 고속유동층으로의 전이유속(U_tr)에 대한 온도(25-600 ℃)의 영향을 측정 및 고찰하였다. 측정된 최소유동화속도는 온도와 압력이 증가함에 따라 감소하였으며, 고속유동층으로의 전이유속은 온도가 증가함에 따라 증가하였다. 최소유동화속도와 고속유동층으로의 전이유속에 대한 본 실험의 측정값을 기존의 상관식과 비교하였으며 기존 상관식을 바탕으로 수정된 상관식을 제시하였다.

In order to design and select appropriate operating conditions for the practical operation of chemical-looping combustor, which consists of two interconnected fluidized beds (bubbling fluidized bed and fast fluidized bed), minimum fluidization velocity and transition velocity to fast fluidization were measured and investigated. Oxygen carrier particle of NiO/bentonite particle (specific surface mean diameter: 0.181 mm, particle density: 4,080 kg/m³) was used as a bed material. The minimum fluidization velocity was determined by measuring the bed pressure drop in the pressurized fluidized bed (0.052 m i.d. and 1.66 m high) with variations of temperature (25-1,000 ℃) and pressure (1-6 atm). The transition velocity from bubbling to fast fluidization was determined by means of emptying time method in the high temperature circulating fluidized bed (0.02 m i.d. and 2.0 m high) with variation of temperature (25-600 ℃). The measured minimum fluidization velocity was increased with increasing temperature and pressure. The measured transition velocity to fast fluidization was increased with increasing temperature. The previous correlations on the minimum fluidization velocity and transition velocity to fast fluidization were compared with the present measured values to develop new correlation.

Chemical-Looping Combustion Transition Velocity Oxygen Carrier Particle Circulating Fluidized Bed Pressurized Fluidized Bed

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