Search / Korean Journal of Chemical Engineering
HWAHAK KONGHAK,
Vol.36, No.5, 797-803, 1998
고속유동층에서의 기체혼합특성
Gas Mixing Characteristics in a Fast Fluidized Bed
고속유동층 반응기(직경 0.1m, 높이 5.3m)에서 층물질로 silica sand 입자를 사용하여 기상유속과 고체순환속도가 기체의 반경방향혼합 및 기체역혼합특성에 미치는 영향을 연구하였다. 반경방향의 기체분산계수(Dr)는 고체체류량이 증가할수록 증가하였다. 반경방향의 분산계수(Dr)에 대한 상관식을 Froude number와 무차원군을 사용하여 제시하였다. 벽면 근처에서는 입자의 하강흐름으로 인하여 상당한 양의 기체역혼합이 관찰되었지만, 중심영역에서는 기-고의 높은 상승흐름으로 인하여 기체의역혼합은 크게 감소하였다. Peclet number의 항으로 기체역혼합계수에 대한 상관식을 무차원군을 사용하여 제시하였다
The effects of gas velocity and solid circulation rate on the radial gas mixing and backmixing characteristics have been determined in a fast fluidized bed(0.1m- I.D.X5.3m-high). Radial gas mixing coefficient(Dr) increases with increasing solid holdup. Radial gas mixing coefficient has been correlated with the Froude number and the pertinent dimensionless groups. The considerable amount of backmixed tracer gas near the wall region is observed due to the downflow of solids. However, at the center region of the bed, gas backmixing is negligibly small due to high upward flow of gas-solid mixture. Gas backmixing coefficient in terms of Peclet number has been correlated with the dimensionless groups.
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