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Downer 반응기에서의 축방향 압력 및 고체체류량 분포

Axial Pressure and Solid Holdup Profiles in a Downer Reactor

방진환 김용전 김상돈^†

Jin-Hwan Bang Yong-Jeon Kim Sang-Done Kim^†

한국과학기술원 화학공학과 및 에너지&환경연구센터, 대전

Dept. of Chem. Eng. & Energy and Environment Research Center, KAIST, Taejon, Korea

kimsd@kaist.ac.kr

HWAHAK KONGHAK, August 2000, 38(4), 503-509(7), NONE

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Abstract

Downer 반응기(0.1 m-I.D.×3.5 m-high)에서 축방향 압력과 고체체류량분포에 대한 기체유속, 고체순환속도, 입자크기의 영향을 고찰하였다. 축방향의 압력구배는 고체순환속도에 비례하고 기체유속에 반비례하였다. 주어진 기체유속과 고체순환속도에서 입자크기는 축방향 압력 구배와 고체체류량에 큰 영향이 없었다. 완전 발달흐름영역(H>2.0 m)에서는 기체 유속이 낮을 때 (<3.0 m/s)단일 입자의 속도로부터 예측된 압력 구배가 실험결과보다 높은 값을 보였으나 높은 유속에서는 시험결과와 유사한 값을 보였다. 이는 입자의 뭉침(cluster의 형성)때문으로 slip velocity와 단일입자의 종말속도의 차이로 확인하였다.

The effects of gas velocity, solid circulation rate, and particle size on the axial pressure profiles and solid holdup in the downer reactor have been determined. The axial gradients increase with increasing solid circulation rate but decrease with increasing gas velocity. However, the effect of particle size on the pressure gradients and solid holdup is insignificant at the given gas velocties and solid circulation rates. In the fully developed flow region(H>2.0m), pressure gradients calculated from a single particle motion are higher than the experimental values at lower gas velocities(<3.0 m/s),whereas they are similar to the experimental values at higher gas velocities(>3.0 m/s),due to the particle agglomeration or cluster formation that was confirmed by the comparison of slip and terminal velocities of a single and cluster particles.

Keywords

Downer Circulating Fluidzed Bed Pressure Gradient Slid Holdup

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